EPA 430/K94/024
      MONTREAL PROTOCOL
ON  SUBSTANCES  THAT  DEPLETE
         THE OZONE LAYER
          UNEP
             1994 Report of the
      Solvents, Coatings and Adhesives
        Technical Options Committee
              1995 Assessment

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                        UNEP
     . • '  -  1994 Report of the
Solvents, Coatings and Adhesives
   Technical Options Committee

               1995  Assessment

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Montreal Protocol
On Substances that Deplete the Ozone Layer

UNEP
1994  Report of the
Solvents, Coatings and Adhesives
Technical Options Committee

1995  Assessment
The text of this report is composed in Courier.
Composition and co-ordination:     Stephen 0. Andersen (Chair TOC)
Layout:                         Stephen 0. Andersen
                                J. Clayton French
Reprinting:                      UNEP Nairobi, Ozone Secretariat
Date:                           30 November 1994
No copyright involved.
Printed in Kenya; 1994.
ISBN 92-807-1456-2

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         1994 Report of the
   Solvents, Coatings and Adhesives
     Technical Options Committee

              for the
           1995  Assessment
               of the
         U  N-E-.P
     MONTREAL PROTOCOL
ON SUBSTANCES THAT DEPLETE
       THE OZONE LAYER
             pursuant to
             Article 6
        of the Montreal Protocol;
         Decision IV/13 (1993)
    by the Parties to the Montreal Protocol

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                                       Disclaimer
                                                *
The  United  Nations  Environment Programme  (UNEP),  the  Technology  and  Economics
Assessment Panel  co-chairs and members, the Technical  and Economics Options Committees
chairs and members and the companies and organisations that employ them do not endorse the
performance,  worker  safety, or environmental  acceptability of any  of the  technical options
discussed. Every industrial  operation requires consideration of worker safety and proper disposal
of contaminants and waste products. Moreover, as work continues  -including additional toxicity
testing  and  evaluation-   more information  on  health, environmental and  safety effects  of
alternatives and  replacements  will  become available  for  use  in selecting among the options
discussed in this document.

UNEP,  the Technology and Economics  Assessment Panel co-chairs  and members,  and  the
Technical and Economics Options Committees  chairs and members, in furnishing or distributing
this information, do not make  any  warranty or  representation,  either  express or implied, with
respect  to the accuracy, completeness or utility; nor do they assume  any liability of  any kind
whatsoever resulting from  the  use  or  reliance upon, any information,  material,  or procedure
contained herein, including but  not limited to any claims regarding health, safety, environmental
effects or fate, efficacy, or performance, made by  the source of information.

Mention of any company, association, or product in  this document is for  information  purposes
only and does not constitute a  recommendation of any such company, association, or product,
either express or implied.by UNEP, the Technology and Economics Assessment Panel  co-chairs
and members, and  the Technical and Economics  Options Committees chairs and members or the
companies or organisations that employ them.
                                  Acknowledgement

The UNEP Solvents, Coatings and Adhesives Technical Options Committee acknowledges with
thanks, the outstanding contributions from all of the individuals and organisations who provided
technical support to committee members.

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  1994 UNEP SOLVENTS, COATINGS, AND  ADHESIVES
                  TECHNICAL OPTIONS REPORT
              UNEP SOLVENTS, COATINGS, AND ADHESIVES
                     TECHNICAL OPTIONS COMMITTEE
Committee member
                i
Dr. Husamuddin Ahmadzai
Mr. Lorenzo Alvarez
Dr. Stephen O. Andersen
Dr. David Andrews
Mr. Jay Baker
Mr. Bryan H. Baxter
Mr. Charles Carpenter
Mr. Pakasit  Chanvinij
Mr. Mike Clark
Mr. Jorge Corona
Mr. Brian Ellis
Mr. Stephen Evanoff
Mr. Joe R. Felty
Dr. John Fisher
Mr. Art FitzGerald
Ms. Pamela  Foster
Mr. Yuichi Fujimoto
Ing. G. Gabelmann
Dr. Leslie Guth
Mr. Don Hunt
Mr. Yoshiyuki Ishii
Mr. Peter Johnson
Dr. William Kenyon
Mr. Sudhakar Kesavan
Mr. Hiroshi Kurita
Dr. Steve Lai

Mr. Leo-Lambert
Mr. Milton Lubraico
Dr. Mohinder Malik
Mr. Shigeo Matsui  .
Ms. Annie Maurel-Groleau
Mr. James A. Mertens
Mr. Hank Osterman
Mr. Fritz Powolny
Ms. Cynthia Pruett
Affiliation

Statens Naturvardsverk
SAEO South America Electronics Operation
U.S. EPA
GEC-Marconi Hirst Research Centre
Ford Electronics Technical Center
British Aerospace (Dynamics) Ltd.
Waste Policy Institute
Thai Airways International
Sketchley PLC
Mexican Chamber of Industries
Protonique S.A.
Lockheed Environmental
Texas Instruments Inc.
AT&T Bell Laboratories
IFC
Friends of the Earth
JEMA
ITT Teves GmbH
AT&T Bell Laboratories
U.S. Air Force
Hitachi Ltd.
European Chlorinated Solvents Association
Global Centre for Process Change
ICF Inc.
Japan Assoc. for Hygiene of Chlorinated Solvents
Singapore Institute of Standards and
  Industrial Research
Digital Equipment Corp.
Ford Motor Company
Lufthansa German Airlines
Japan Audit and Certification Organisation Ltd.
TELEMECANIQUE
Dow Chemical - Advanced Cleaning Systems
Allied Signal, Inc.
OXITENO
Consultant
Country

Sweden
Brazil
USA (Chairman)
UK
USA
UK
USA
Thailand
UK
Mexico (Vice Chairman)
Switzerland
USA
USA
USA-
Canada
Canada
Japan
Germany
USA
USA
Japan
Belgium
USA
USA
Japan
Singapore

USA
Brazil
Germany
Japan
France
USA
USA
Brazil
USA '
                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

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               UNEP SOLVENTS, COATINGS, AND ADHESIVES
                TECHNICAL OPTIONS COMMITTEE (continued)
Committee member      Affiliation                              Country

Mr. Patrice Rollet           Promosol                                 France
Mr. Wolf-Eberhard Schiegl     Siemens AG                               Germany
Mr. Hussein Shafa'amri       Ministry of Planning                         Jordan
Lt. Col. John Shirtz          U.S. Air Force                             USA
Mr. Darrel Staley            Boeing Company                           USA
Dr. John Stemniski           Charles Stark Draper Laboratory               USA
Lt. Col. Doug van Mullem     U.S. Air Force                             USA
Mr. John Wilkinson          Vulcan Chemicals                           USA
Dr. Masaaki Yamabe         Asahi Glass Co., Ltd.                        Japan
Mr. X'Avier Hk Yoong       National Semiconductor                      Malaysia
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

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                               TABLE OP CONTENTS


        UNEP SOLVENTS,  COATINGS, AND ADHESIVES TECHNICAL OPTIONS REPORT
GLOSSARY	•.   xvi

EXECUTIVE  SUMMARY	  .  ES-1

1.    INTRODUCTION	.'....	1-1

      1.1   BACKGROUND'  .  .  .  .-	,	1-1.

     .1.2   TERMS OF REFERENCE  FOR THE  COMMITTEE	   1-4

      1.3   BASIS FOR COMMITTEE RECOMMENDATIONS TO  UNEP  AND 'COMMITTEE
            POSITION ON  CFC-113,' 1,1,1-TRICHLOROETHANE AND PARTIALLY
            HALO"GENATED  FLUOROCARBONS	  .   1-9

2.    ELECTRONICS INDUSTRY APPLICATIONS	  .'	2-1

      2.1   BACKGROUND   .[	'.	'....',.   2-1

      2.2   PRINTED CIRCUIT  DESIGN FOR  EFFICIENT  SOLDERING AND 'CLEANING  .   2-4

            2.2.1  Low-Solids "No-Clean" Flux Wave  Soldering   ......   2-4
            2.2.2  Controlled Atmosphere Soldering	:  .  .  .   2-5
            2.2.3  "Traditional" Flux Soldering and Cleaning	   2-7
            2.2.4  "Glue-Spots" and Cleaning Quality  :	  2-10
            2.2.5  "No-^Clean" Paste Reflow Soldering	2-10
            2.2.6  "Traditional" Paste  Reflow Soldering  and Cleaning  .  .  2-10

      2.3   CFC-113-USE  IN ELECTRONICS ASSEMBLIES  .  .  .  .	  .2-10

            2.3.1  Major Assembly Processes	2--10
            2.3.2  Flux  Types	2-11

      2.4   PRODUCTION PROCESSES	'	2-13

            2.4.1  "No-Clean" Processes	2-13

                  2.4.1.1  Low-Solids "No-Clean"  Processes	  .  2-15
                  2.4.1.2  High-Solids  "No-Clean" Processes 	  2-15
                  2.4.1.3  Controlled Atmosphere  Soldering	'.  .2-16

            2.4.2  Water Soluble Processes	  .  2-16

                  2.4.2.1  Traditional Water Soluble Process   	  2-17
                  2.4.2.2  "Glycol-Free" Water Soluble Process  	  2-18
                    '• 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

                                      - i-

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      2.4.3  Saponification Processes  .  .  .'	2-18
      2.4.4  Hydrocarbon-Surfactant  (HCS or  HC/S. Processes   ....  2-19

            2.4.4.1  Seperable HCS Processes  	  .....  2-20
            2.4.4.2  Miscible Processes  	  2-21

      2.4.5  HC and Derivative Processes	2-21

            2.4.5.1  Light HC Solvent  Processes  	  2-21
            2.4.5.2  Heavy HC Solvent  Processes  	  2-22

      2.4.6  Permitted Halocarbon Processes  ............  2-22

            2.4.6.1  Non-Ozone-Depleting Chlorinated  Processes   .  .  2-23
            2.4.6.2  HCFC Solvent Processes	•.  ..2-23

2.5   MACHINERY FOR ENVIRONMENTALLY  RESPONSIBLE  SOLDERING
      AND CLEANING	2-24

      2.5.1  Conventional Wave Soldering   	  2-24
      2.5.2  Controlled Atmosphere Wave Soldering	  2-25
      2.5.3  Infra-Red Etc. Solder Paste Reflow  .	2-25
      2.5.4  Vapour.-Phase Solder Paste Reflow	2-26
      2.5.5  Hot Liquid Immersion Solder Paste Reflow 	  2-26
      2.5.6  Aqueous Cleaning (Conventional  Water-Soluble Fluxes)  .  2-27
      2.5.7  Aqueous Cleaning (Glycol-Free Water-Soluble Fluxes)   .  2-27
      2.5.8  Saponifier Cleaning	' .  .  2-28
      2.5.9  HCS Solvents :	 .  .  2-28
      2.5.10 HC Solvents and Derivatives   	  2-29
      2.5.11.Permitted Halocarbon Solvents   	  2-30

2.6   PRODUCTION MACHINERY AND MATERIALS	  .  .  .'.  2-30x

      2.. 6.1  Conventional Wave Soldering Machines  .  .	2-31
      2.6.2  Controlled Atmosphere Wave Soldering Machines   .  .  .  .2-34
      2.6.3  Vapour Phase Reflow "...	  2-36
      2.6.4  Infra-Red Reflow Machines	  2-36
      2.6.5  Other Reflow Methods	•..'..	2-37'

2.7   CLEANING MACHINERY  	  2-38

      2.7.1  "Dishwasher" Types	2-38
      2.7.2  "High-Throughput" Types   	  2-38
      2.7.3  "Tank-Line" Batch Types   	  2-39
      2.7.4' Totally Enclosed Types  	  2-39
      2.7.5  Conveyorised "In-Line" Machines	•	  .  2-40
      2.7.6  Vapour Phase Solvent Machines   	  2-41

2.8   MACHINE AGITATION	2-41

      2.8.1  Sprays for Cleaning	2-41
      2.8.2  Sprays for Rinsing	2-42
      2.8.3  "Under-Surface" Spraying  	  2-43
      2.8.4 -Ultrasonic Agitation 		  2-43
              * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                               - ii-

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      2.9   DRYING	-...!•..  2-45

            2.9.1  Mechanical Drying	2-45
            2.9.2  Evaporative Drying	  2-46
            2.9.3  Vapour Phase Drying	2-47

      '2.10  CONTAMINATION AND QUALITY CONTROL.'	•	2-48

            2.10.1 Soldei-ability Testers   .	2-49
            2.10.2.Ionic Contamination Testing   	'....'...'..  2-49
            2.10.3 Surface Insulation Resistance  and  ElectromigratioiT
                   Testing	.'	2-50

      2.11  PHOTORESIST DEVELOPMENT	  2-50

      2.12  SUMMARY	.2-51

3.  '   PRECISION CLEANING APPLICATIONS	.3-1

      3.1   BACKGROUND	•	   3-1

      3.2   CFC-113 AND 1,1,1-TRICHLOROETHANE USE IN  PRECISION
            CLEANING APPLICATIONS	  .  .	3-3

            3.2.1  Precision Cleaning Processes and Equipment  ......   3-3
            3.-2.2  Precis'ion Cleaning Applications	3~6,

                  3.2.2.1  Cleaning Precision Instruments During
                              Manufacture, Assembly,  and Testing   ....   3-6
                  3.2.2.2  Specialised Manufacturing  Techniques  .  .  '.  .  .3-11
                  3.2.2.3  Maintenance Cleaning and Repair   .  .  .  .•.  .  .3-12

      3.3   ALTERNATIVES- FOR REDUCING OR REPLACING CFC-113 AND
            1,1,1-TRICHLOROETHANE IN PRECISION CLEANING  . 	3-13

            3.3.1  Conservation and Recovery Practices   	  3-13
            3.3.2  Aqueous Cleaning		3-13
            3.3.3  Semi-Aqueous Cleaning   .	3-19
            3.3.4  HCFCs  .  . .  '.	3-23
            3.3.5  Alcohols and Ketones	3-28
            3.3.6  Perfluorocarbons	   	  3-30
            3.3.7  Alcohol Cleaning with Perfluorocarbons 	  3-32
            3.3.8  Aliphatic Hydrocarbons	.	3-34
            3.3.9  Chlorinated and Other Miscellaneous Organic
                        Solvents	3-37
            3.3.10 Pressurized Gases  	  .  	  3-37
   '         3.3.11 Supercritical Fluids 	  3-42
            3.3.12 Plasma Cleaning  ,.	3-47
            3.3.13-Ultraviolet Light/Ozone Cleaning Method   	  3-50

      3.4   ENVIRONMENTAL AND ENERGY CONSIDERATION	''-:3-51

      3.5   POTENTIAL GLOBAL REDUCTION OF CFC-113 AND
   /  '      1,1,1-TRICHLOROETHANE .IN PRECISION CLEANING APPLICATIONS   .  .  3-52
                     1994 UNEP SOLVENTS,  COATINGS. AND ADHESIVES REPORT '••
                                     -iii-

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4.-    METAL CLEANING APPLICATIONS	4-1

      4.1   BACKGROUND	4-1

      4.2   CFC-113 AND 1,1,1-TRICHLOROETHANE USE IN METAL CLEANING
            APPLICATIONS		  4-3

            4.2.1  Metal Cleaning Applications  	  4-3
            4.2.2  Metal Cleaning Solvents  	  4-3
            4.2.3  Metal Cleaning Processes 	  4-4

                  4.2.3.1 Cold Immersion Cleaning 	  4-4
                  4.2.3.2 Vapour/Hot Liquid Cleaning   	  .  4-4
                  4.2.3.3 Conveyorized Cleaning	-	4-7
                  4.2.3.4 Manual Cleaning  . .  	  4-7
                  4.2.3.5 Spraying and Flushing Techniques   	  4-7

      4.3   ALTERNATIVES FOR REDUCING OR REPLACING CFC-113 AND 1,1,1-
            TRICHLOROETHANE USE IN METAL CLEANING APPLICATIONS   	  4-8

            4.3.1  Conservation and Recovery Practices   	  4-8
            4.3.2  Alternative Chlorinated Solvents 	  4-8
            4.3.3  Alternative Solvent Blends 	  .... 4-10

                  4.3.3.1 Vapour Degreasing	'. .   .  .''...  .4-10
                  4.3.3.2 Manual Cleaning	  . 4-10
                  4.3.3.3 Cold Immersion Cleaning 	 4-11

            4.3.4  Aqueous  Cleaners 	 4-11

                  4.3.4.1 Cleaner Formulations  	 4-11
                  4.3.4.2 Aqueous Cleaning Processes   	 4-13

                        4.3.4.2.1  Immersion Cleaning •.  .	4-13
                        4.3.4.2.2'  Ultrasonic Cleaning   	 4-15
                        4.3.4.2.3  Spray Cleaning 	   ..... 4-16

            4.3.5  Hydrocarbon/Surfactant  ("Semi-aqueous" and
                        "Emulsion")  Cleaners  	 4-18
            4.3.6  Mechanical Cleaning  	 4-19
            4.3.7  Thermal-Vacuum De-oiling 	 4-21
            4.3.8  No-Clean Alternatives	 4-21
            4.3.9  CFC-113  and 1,1,1-Trichloroethane Processes
                   for Which Alternatives are Not Available  	 4-22

      4.4   COST OF ALTERNATIVES	4-22

      4.5   ENVIRONMENTAL,  HEALTH,  AND SAFETY CONSIDERATIONS   ...... 4-23

      4.6   POTENTIAL GLOBAL REDUCTION OF CFC-113 AND
            1,1,1-TRICHLOROETHANE IN METAL CLEANING APPLICATIONS   .... 4-23

      4.7   SUITABILITY OF  ALTERNATIVES FOR DEVELOPING COUNTRIES
            AND SMALL QUANTITY USERS  	...'.'	  .  .  . 4-24
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     - IV-

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5.     DRY CLEANING INDUSTRY	   5-1

      5.1   BACKGROUND	5-1

      5.2   CFC-113 AND  1,1,1-TRICHLOROETHANE USE  IN  THE  DRY CLEANING
            INDUSTRY   .  . .  :	  .   5-1'

            5.2.1 Dry Cleaning Machines	5-2

      5.3   ALTERNATIVES FOR REDUCING OR REPLACING CFC-113  AND  1,1,1-
            TRTCHLOROETHANE  USE	   5-5

            5.3.1  Conservation  and Recovery Practices   ., 	   5-5
            5.3.2  Alternative Solvents..  	   5-7

                  5.3.2.1 Perchloroethylene	   5-7

                  5.3.2.2 Petroleum Solvents (White Spirit,  Stqddard
                          Solvent, Etc.)	   5-9'
                  5.3.2.3 Hydrofluorocarbons (HCFCs)   	  	   5-9
                  5.3.2.4 Other  Alternative Solvents   .....  	   5-9
                  5.3.2.5 Centralized Processing Facilities  	  5-10,

      5.4   COST OF ALTERNATIVES   ........./	5-10

      5.5   ENVIRONMENTAL AND ENERGY CONSIDERATIONS 	  5-10

      5.6   POTENTIAL GLOBAL REDUCTION OF.  CFC-113  USE IN  THE
            DRYCLEANING  INDUSTRY	:  .  .  .  5-12

6.     ADHESIVE APPLICATIONS	-. •  6-1

      6..1   BACKGROUND	6-1

      6.2   1,1,1-TRICHLOROETHANE USE IN ADHESIVE? APPLICATIONS  .....   6-1

      6.3   ALTERNATIVES FOR REDUCING OR REPLACING
            1,1,1-TRICHLOROETHANE USE	6-4

            6.3.1 Other 'Solvent-Based Adhesives	   6-4
            6.3.2 Water-Based Adhesives  	   6-6
            6.3.3 Hot Melt Adhesives  .  .  .	6-7
            6.3.4 Radiation  Cured-Adhesives	   6-8
            6.3.5 High Solids Adhesives,.	'	6-8
            6.3.6 Powders	   6-9
            6.3.7 Non-Volatile Solids and  Liquids  arid Reactive Liquids   . '  6-9

      6.4   COSTS OF ALTERNATIVES	  .  6-10

      6.5   ENVIRONMENTAL AND ENERGY CONSIDERATIONS	  6-10

      6.6   POTENTIAL GLOBAL REDUCTION OF  1,1,1-TRICHLOROETHANE
            USE IN THE ADHESIVES INDUSTRY  .  .'	  6-11-
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      -V-

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      6.7   SUITABILITY OF ALTERNATIVES  FOR DEVELOPING COUNTRIES AND
            SMALL QUANTITY USERS	  6-12

7.    COATINGS AND INKS APPLICATIONS	7-1

      7.1   BACKGROUND	'	   7-1

      7.2   CFC-113 AND 1,1;1-YRICHLOROETHANE  USE  IN  COATINGS  AND INKS
            APPLICATIONS	'	'.  .   7-1

      7.3   ALTERNATIVES FOR REDUCING  OR REPLACING CFC-113  AND L.,1,1-'
            TRICHLOROETHANE USE  .  .  .	7-2

            7.3.1 Water-based Coatings and  Inks	  .   7-2
            7.3.2 High-Solid Coatings	  :	7-2
            7.3.3 Powder Coatings	  .  ,	7-3
            7.3.4 UV/EB-Cured Coatings and  Inks	7-3

      7.4'  ENVIRONMENTAL AND ENERGY CONSIDERATIONS	'..'...   7-3

8.    AEROSOLS APPLICATIONS .• .  ,	•	8-1

      8.1   BACKGROUND	   8-1

      8.2   CFC-113 AND 1,1,1-TRICHLOROETHANE  USE  IN  AEROSOL PRODUCT
            APPLICATIONS  .	.••.-•'	8-l

      8.3   ALTERNATIVES FOR REDUCING  OR REPLACING CFC-113  AND
            1,1,1-TRICHLOROETHANE USE  IN AEROSOL PRODUCTS	'.  .   8-2

          .  8.3.1 Reformulation Using  Petroleum Distillates 	   8-4
            8.3.2 Reformulation to Water-based Systems   	  ....   8-4
            8.3.3 Reformulation Using  Organic  Solvents   	   8-4
            8.3.4 Reformulation Using  Nonozone-Depleting Chlorinated
                  Solvents	,8-5
            8.3.5 Reformulation Without  a Solvent  	   8-5
            8.3.6 Reformulation Using  HGFCs	•	   8-5
            8.3.7 Alternative Delivery Systems  	   8-6

      8.4   COSTS OF ALTERNATIVES	-	   8-6

9.    OTHER SOLVENT USES OF CFC-113 AND  1,1,1-TRICHLOROETHANE  	   9-1

      9.1   BACKGROUND  	-	9-1

      9.2   BEARER MEDIA FOR COATING AND IMPREGNATION :  	   9-1

      9.3   VAPOUR SOLDERING TECHNOLOGY	'.	• :  .  .   9-2

      9.4   COMPONENT DRYING	,	9-5

            9.4.1 Semiconductors   .	 •	9-5
            9.4.2. Printed Circuit Boards  ...'........:....   9-5
            9.4.3 Mechanical Assemblies  .'......-...  i  -.•..-....   9-7
            9.4.4 Metal Surfaces	..'.-.......•.....   9-7

                   * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     -vi-

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      9.5   RIVETING AND MACHINING	9-7

      9.6   AIRPLANE HYDRAULIC  SYSTEM  TESTING	, •  •  •   9-8

      9.7   FABRIC PROTECTION AND COATING	9-9

      9.8   SEMICONDUCTOR MANUFACTURING  	  9-10

            9.8.1 Plasma Etch Processing   	.'.9-10
            9.8.2 Oxide Growth  processing  .  .  '. '	9-11
            9.8.3 Semiconductor Degreasing  	  9-11
            9.8.4 Photolithographic  Prcocessing  	  :  	  9-14


      9.9   MISCELLANEOUS TESTING	•	9-14

            9.9.1 Leak Testing	9-14
            9.9.2 Laboratory Testing	  .  9-14

      9.10  MOULD RELEASE AGENTS	  ,	9-14

      9.11  FILM CLEANING ....'.....	9-1*5

      9.12  COMPONENT COOLING ........'	  9-16

      9.13  MANUFACTURE OF SOLID ROCKET MOTORS	.  .  9-17

      .9.14  OXYGEN SYSTEMS CLEANING	• .  .	9-20
                                  "\
      9.15  CORRECTION FLUIDS 	  .9-23

      9.16  FABRIC SPOT REMOVER	 9-23

      9.17  PROCESS SOLVENTS	9-23

10.    ALTERNATIVES TO OZONE-DEPLETING  SOLVENTS IN  DEVELOPING,
      COUNTRIES ..."	'	10-1

      10.1  INTRODUCTION	10-1

      10 ..2  SUBSTITUTES AND ALTERNATIVES	10-1

           10.2.1  No-Clean Electronics	  10-2
           10.2.2  No-Clean Metal Finishing/Fabrication/Assembly   .  .  .  .  1.0-2
           10.2.3  Aqueous Cleaning	 .'	10-3
           10.2.4  Semi-Aqueous Cleaning   .  . •	  .  10-4
           10.2.5  Organic Solvent Cleaning  (alcohols, aliphatics,
                   ketones,  aldehydes, 'and blends  or C1-C20,
                   hydrocarbons and  derivatives	  .  10-5
           10.2..6  Chlorinated  Aliphatic Solvent Cleaning
                   (trichloroethylene, perchloroethylene or
                   dichlorome thane)	,	.•  •  •  10-5
           10.2.7  Chlorinated  Aromatic Solvent Cleaning
                   (monochlorotoluene/benzotrifluorides)   	  10-6
           10.2.8  Hydrofluorocarbons  (HCFC-123, HCFC-141b,  HCFC-225)  .  .  10-6


                    '• 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     -vii-

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           10.2.9  Perfluorocarbons  	  10-7
           10.2.10 Hydrofluorocarbons  (HFCs)	;	10-8
           10.2.11 Dibromethane	'	10-8
           10.2.12 Volatile Methyl Siloxanes' (VMSs)  .	-.  .  .  10-9
           10.2.13 Supercritical Fluid Cleaning  	 ....  10-9
           10.2.14 Carbon^Dioxide Snow Cleaning.	10-10
           10.2.15 Plasma Cleaning	10-10
           10.2.16 Ultraviolet/Ozone Cleaning  	   10-10

      10.3  TECHNOLOGIES FOR DEVELOPING COUNTRIES  .  .  .  ....  .  •.  .  .  .   10-12

           10.3.1  No-Clean	  .   10-13
           10:3.2  Aqueous/Semi-Aqueous Cleaning	   10-13
           10.3.3  Organic Solvent Cleaning  	   10-13
           10.3.4  Non-Ozone-Depleting Halogenated Solvents  	   10-14
           10.3.5  HCFC-123, HCFC-225, HCFC-141b, and  PFCs	   10-14

      10.4  RETROFITS	:  .   10-14
11.    CASE STUDIES OF PHASEOUT ACTIVITIES	11-1

            ALLIED SIGNAL - An Evaluation of Aqueous Technologies  .  .  .  . 11-4

            AT&T BELL LABORATORIES - Eliminating Ozone-Depleting
                •  Substances at AT&T  .  .   .	11-6

            BECK ELECTRONICS - Semi-Aqueous Equipment Conversion at
                  Beck Electronics	s	'	11-10

            FORD MOTOR COMPANY - CFG Solvent Elimination in
                  Electronics Soldering at Ford Motor Company  	  11-13

            HITACHI - Reduction and Elimination of Ozone-Depleting
                  Solvents at Hitachi	10-17

            HONEYWELL - Replacement of Ozone-Depleting Substances
                  in Honeywell Space and Aviation Control Products   ...  11-20

         :   IBM CORPORATION - ODS Elimination at IBM Austin, Texas   .  .  11-23

            THE JAPAN INDUSTRIAL CONFERENCE ON CLEANING .........  11-26

            LOCKHEED SANDERS COMPANY - The Elimination of .
                  1,1,1-Trichloroethane in Electronics Cleaning at
                  Lockheed Sanders Company	•	 11-29

            MILJOMINISTERIET - Hydrocarbon Dry Cleaning at
                  Miljoministeriet	:  .  11-33

            MINEBEA COMPANY - Phasing Out of Ozone-Depleting Substances
                  by the Minebea Co. Through the Use of a Water-Based
                  Cleaning System 	  11-35
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                    -viii-

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             NATIONAL SEMICONDUCTOR - Non-ODS Alternatives in the
                   Cleaning of Integrated Circuits at National
                   Semiconductor - Malaysia  	  11-37

             NAVAL AVIATION DEPOT - Implementation of ODS Alternatives
                   at Naval Aviation Depot Cherry Point	  11-39

             NORTHERN TELECOM -  CFC-113 Elimination at Northern
                   Telecom	11-43

             ROBERT BOSCH CORPORATION - Replacing Solvent Cleaning
                   with Aqueous  Cleaning at Robert Bosch Corporation .   .  11-47

             ROCKWELL INTERNATIONAL - Use of a Low Residue Flux in a
                 . .Military Electronics Program	'.  .  .   .  11-52

             SEIKO  EPSON CORPORATION -  The Cleaning Center System  of
                   Seiko Epson Corporation 	  11-57

             SINGAPORE INSTITUTE OF STANDARDS AND INDUSTRIAL RESEARCH -
                   The ODS-Free  Verification Scheme for Singapore
                   Industry		  11-62

             SWEDISH EPA - Eliminating  the Use  of ODSs in Sweden  ....  11-66

             TOSHIBA CORPORATION -  Non-ODS Substitutes for Wax
                   Elimination at Toshiba Corporation	 .  .  .  11-68

             U.S. AIR FORCE AEROSPACE GUIDANCE  AND METROLOGY CENTER -
                   Using New Technologies, to Solve Unique Precision'
                   Cleaning Operations:  The Elimination of Ozone -
                   Depleting Solvents From the  Aerospace and Metrology
           •  .      Center Newark Air Force Base,  Ohio	11-71

             VIBRO-METER SA -  Case  Study:  Vibro-Meter SA,  Villars-sur-
                   Glane,  Switzerland	-	11-75
REFERENCES	'	R-l
APPENDIX A: Members of the UNEP  Solvents, .Coatings  and Adhesvies
            Technical Options Committee  for  Technical Assessment
            for Technical Assessment Under Article  6 of  the  Montreal
            Protocol   	_• . •	A-l

APPENDIX B: Expert Advisors  to UNEP Solvents,  Coatings and
            Adhesives Technical  Options  Committee	• .' .  .  .   B-l

APPENDIX C: Recommended Guidelines and Control Achievable with  Best
            Available Technology (BAT) for Volatile Organic
            Compound  (VOC) Solvent-Based Cleaning	   C-l

APPENDIX D: CFC-113 and 1,1,1-Trichloroethane  Chemical,  Trade,  and
'.  . •        Company Names	.......'....	, .   D-l


                    *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES. REPORT ••
                                     -ix-

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APPENDIX E: Site Visits	•  E-l

APPENDIX F: German  Solvent Use Regulations   	  .  F-l

APPENDIX G: Summary of Testing Programs for Alternatives  in the
            Electronics  Industry in Sweden,.United Kingdom,  and the
            United  States •....:•	'.  .  :	G-l

APPENDIX H: Analysis of  Current and Future Production  of  Carbon
            Tetrachloride	  .H-l

APPENDIX I: Total Equivalent Warming Impact  (TEWI) of  Solvent
            Alternatives  	.1-1
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       -X-

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                                 LIST  OF FIGURES
                                                                          Page

 Figure 1-1.        1,1,1-Trichloroethane Reduction Schedule
                   (User Survey Results for Western Europe, North
                   America, and Japan)	1-7

 Figure 1-2        Relative Total Ozone Depleting Potential of Selected
                   Halogenated Solvents	   .   . 1-15

 Figure II-l.       Methods of Replacing Ozone-Depleting Solvents in the
                   Electronics Industry  	  2-3

 Figure II-2.       Hypothetical Example of SMD Circuit Designed for
                   "No-Clean" Wave Soldering Showing Correct Orientation
                   of Components	.....2-6

 Figure II-3.       Layout Criteria for Effective Cleaning a) Orientation
                   and .Position	 .   . . 2-8

 Figure II-4.       Layout Criteria for Effective Cleaning b) Maximum
                   Ingress of Cleaning Fluids  	 ......  2-9

 Figure III-l.      Size  Comparison of Computer Disk Drive Head
                   Clearance with Various Contaminants ..-....'....  3-2

 Figure III-2. •    ' Metal Cleaning and Precision Cleaning 	  3-4

 Figure III-3.      Configuration of a Typical Aqueous Cleaning Process .   . 3-16

 Figure III-4.      Semi-Aqueous Process for Immiscible Hydrocarbon
                   Solvent	  .- . , ,  .'	3-21

 Figure III-5.      Advanced Design Degreaser for Use With Low Boiling
                   Point Solvents	 3-27'

 Figure III-6.      Basic Model Design for Carbon Dioxide Supercritical
                   Cleaning System .  .  .  .  :	 .   . 3-46

 Figure IV-1.       Basic Vapour Degreaser-Batch Cleaning ... •...;.:  4-5

 Figure IV-2.       Degreasing Performance of HCFC-225	   . 4-12

 Figure IV-3.       Configuration of Aqueous Cleaning Process  . .  .  '.  . .   .4-14

.Figure IV-4.       Semi-Aqueous Process for Immiscible Hydrocarbon
                   Solvent	4-20

 Figure V-l.  '   .   Basic Drycleaning Machine Principles  	  5-3
                     ••• 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT '•
                                      -xi-

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Figure V-2.        Typical Layout of Basic Components   	   5-4

Figure XI-1.       Annual Use of CFC-113 and 1,1,1-Trichloroethane  at
                   Honeywell Space and Aviation Control Operattions  .  .   11-.22

Figure XI-2.       Lockheed Sanders Company Stencil Cleaning  Process  .  .   11-30

Figure XI-3.       Lockheed Sanders Company Cicuit Card Cleaning
                   Process	11-31

Figure XI-4.       Minebea Company's Water-Based Cleaning  System  ....   11-36

"Figure XI-5.       Seiko  Epson Cleaning Center System   	  ....   11-58

Figure XI-6.       Cleaning Center Layout  ... 	   11-60

Figure C-l.        Solvent Lost in a Typical Plant	C-2
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     -xii-

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                                 LIST OF'TABLES
Table  I-{L.

Table  1-2.

Table  1-3.


Table  1-4.


Table  1-5.


Table  1-6.



Table  1-7.



Table  II-l.

Table  III-l.

Table  III-2.

Table  III-3.

Table  III-4.

Table  III-5.


Table  III-6.


Table  III-7.

Table  III-8.

Table  III-9.

Table  III-10,

Table  III-ll.
                                                        Page

Parties  to  the Montreal  Protocol	   1-2

Substances  Controlled By the Montreal  Protocol   ....   1-3

Summary  of  Copenhagen Amendments  to  the
Montreal Protocol  .  .  .	-.	1-5

Comparison  of Worldwide  Consumption  of Controlled
CFCs and Ozone Depleting Potential  (OOP)   	   1-6

Member Countries of  the  UNEP Solvents, Coatings  and
Adhesives Technical  Options Committee	•  .  ,  .  .1-10

Organizations Whose  Employees Serve  on the UNEP
Solvents, Coatings,  and  Adhesives Technical
Options Committee	'	1-11

Corporate and Government Presentations in Meetings
Held By  the UNEP Solvents, Coatings, and Adhesives
Technical Options  Committee . .............  1-12

Typical Circuit Board Assembly Contaminants  	  2-14

Aqueous Cleaning	'.......  3-15

Aqueous Cleaning Process  Equipment   .  .  .	  3-17

Physical Properties  of HCFCs and Other Solvents  .  .  .  .3-24

Properties  of Alcohols   	  ........  3-29

Properties  of Perfluorocarbon Solvents Available
in 1994	. .	_.  .  .  3-31

Perfluorocarbon (PFC) Compatibility with Various
Materials	  3-33

Properties  of Aliphatic  Solvents	•.  ...  3-36

Properties  of Halogenated Chlorinated  Solvents  ,	3-38
                                          y
Properties  of Ketones	' .  .  3-39

Supercritical Carbon Dioxide Applications  	  3-43

Supercritical Carbon Dioxide Applications  	  3-45
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     -xiii-

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Table IV-1.


Table V-l.


Table V-2.


Table VI-1.

Table VI-2.

Table VI-3.


Table VIII-1.


Table VIII-2.


Table IX-1.


Table IX-2.

Table IX-3.

Table IX-4.


Table IX-5.

Table XI-1.

Table XI-2.

Table C-.l.


Table C-2.

Table C-3.

Table C-4.


Table C-5.


Table C-6.


Table D-l.
Viable Alternatives to Existing Metal Cleaning
Process Solvents   	  4-9

General Sources of Solvent Losses From Drycleaning
Machines   .	5-6
Chemical Characteristics of Selected Drycleaning
Solvents	
5-8
Physical Properties of Common Adhesive Solvents  ....   6-3

Uses of 1,1,1-Trichloroethane	6-5

Estimated U.S. and European Adhesive Demand By
Segments - 1988	6-13

Summary of Substitute Solvents for
1,1,1-Trichloroethane in Aerosols	   8-3
Costs of Controls for 1,1,1-Trichloroethane  in
Aerosols   	  	
 1-7
Comparison of CFC-113 and a Substitute
Perfluorocarbon as a Secondary Vapour Blanket  .....   9-4

Comparison of Drying Techniques  	   9-6

Halocarbon Plasma Etchants	•	9-12

Possible Mixtures for CFC Replacement in Dry
Etching  .	9-12

CFC Alternative Etching Compounds  .  . '.	9-13

Successful ODS Elimination in Singapore  .  	   11-65

Compositions of Vinyl-Copolymer-Type Masking Agents  .   11-69

Comparison of Recoverability Between CFC-113
Solvent Grades	C-3
Classification of VOCs	,

Comparison of Solvent Recovery Systems
C-4

C-7
A Summary of Available VOG Control Techniques, Their
Efficiencies, and Costs  	  C-8

Typical Emissions From an Optimized Solvents
Cleaning Equipment	•.  .  .  . .C-ll

Values of Specific Emissions Occurring During
Solvent Degreasing Process (ECE Task Force VOC)  .... C-12

CFC Trade Names	D-3
                    " 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     -xiv-

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Table D-2..        CFC-113 Content of Selected Products  	   D-4

Table D-3.         Trade Names for 1,1,1-Trichloroethane 	   D-7

Table D-4.         1,1,1-Trichloroethane  Content of Selected Products   .  .   D-8

Table F-l.         Comparison of US, UK,  and  TRE Internordic
                   Cleaning Options Evaluation Programmes  	  .  .  .   F-2
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      -XV-

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                                    GLOSSARY
Acute toxicity
Adsorption
Aerosol Spray
Alcohols
Aqueous cleaning


Azeotrope
Biodegradable
BOD
Carbon.tetrachloride
CFC

CFC-112

CFC-113
 The  short-term toxicity  of a product in a single dose.
 Can  be  divided into  oral,  cutaneous,  and respiratory
 toxicities.

 Not  to  be  confused with  absorption.   Adsorption is a
 surface phenomenon of  some substances that can form a
 physicochemical bond with  specific  materials.

 A means of  atomizing liquids by  propelling them from a
 pressurized container  through a  suitable valve by
 either  a liquified or  pressurized gas.

•A series of hydrocarbon  derivatives  with at least one
 hydrogen atom  replaced by  an -OH group.   The simplest
 alcohols (methanol,  ethanol,  n-propanol,  and
 isopropanol) are  good  solvents for  some  organic soils,
 notably rosin,  but are flammable and can form
 explosive mixtures with  air.   The use of flammable
 solvents requires  caution  and well-designed equipment.

 Cleaning with  water  to which suitable detergents,
 saponifiers, or other  additives  may  be  added.

 A mixture of chemicals is  an azeotrope  if the  vapour
 composition is identical to  that of-the  liquid phase.
 This means  that the  distillate of an azeotrope is
 theoretically  identical  to the solvents  from which it
 is distilled..  In  practice,  the  presence of
 contaminants in the  solvent  may  upset the azeotropy.

 Products are classified  as biodegradable if they can
 be easily broken  down  or digested by living organisms.

 An abbreviation for  biochemical  oxygen  demand,  a
 measure of  the biodegradability  of wastewater.

 A chlorocarbon solvent with  an ODP  of approximately
 1.1.  It is  also  considered  toxic and a  probable human
 carcinogen  (classified as  a  B2 carcinogen by US EPA).
 Its  use is  strictly  regulated in most countries and it
 is used primarily  as a feedstock material for  the
 production  of  other  chemicals.

 An abbreviation for  chlorofluorocarbon.

 1,1,2,2-tetrachloro-l,2-difluoroethane.

 1,1,2-trichloro-1,2,2-trifluoroethane.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                     -xvi-

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CFC-113a
Chelation
Chlorocarbon


Chlorofluorocarbon



Chronic toxicity



COD

Conformal coating


Controlled
atmosphere soldering



Defluxing



Detergent



Dichloromethane


Dry cleaning-


Dry film


Fatty acids
An isomer of CFC-113; l,l,l-trichloro-2,2,2-
trifluoroethane.

Chelation is the solubilisation of a metal salt by
forming a chemical complex or sequestering.  One way
of doing this is with ethylenediaminetetraacetic acid
(EDTA) salts which have a multidentate spiral  ligand
form that can surround metallic and other ions.

An organic substance composed of chlorine and  carbon,
e.g., carbon tetrachloride.

An organic substance composed of chlorine, fluorine,
and carbon atoms,  usually characterised by high
stability contributing to a high OOP.

The, long-term toxicity of a product in small,  repeated
doses.  Chronic toxicity can often take many years  to
determine'.

An abbreviation for chemical oxygen demand.

A-protective material applied in a thin, uniform layer
to surfaces of an electronic assembly.

A soldering process done in a relatively oxygen-free
atmosphere.  The process greatly reduces oxidation  of
the solder, so .that less flux is required, thereby
reducing or eliminating the need for cleaning.

The removal of flux residues after a soldering
operation.  Defluxing is a part of most high-
reliability electronics production.

A product designed to render -soils (e.g., oils and
greases) soluble in water, usually made from synthetic
surfactants.

A chlorocarbon solvent used extensively for metal
cleaning.  Also known as methylene chloride.

A common term for cleaning garments in organic
solvents, as opposed to water.

A photoresist or photoimageable solder mask applied to
printed circuits by lamination.

The principal part of many vegetable and animal oils
and greases.  Also known as carboxylic acids, which
embrace a wider definition.  These are common
contaminants which use solvents for their removal.
They are also used to activate fluxes.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                     -xvii-

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 Flux
 Greenhouse effect
 Halocarbon
 Halons


•HCFC

 HCS

 HFC

 Hybrid circuits'
 Hydrocarbon
 Hydrocarbon derivative
 Hydrocarbon/surfactant
 solvents
 Hydrochlorocarbon
A chemical employed in the soldering process  to'
facilitate the production of a solder joint.   It  is
usually a liquid or solid material, frequently based
on rosin <(colophony).

A thermodynamic effect whereby, energy absorbed at the
earth's surface and normally radiated back out to
space in the form of long-wave infrared radiation, is
retained due to gases in the atmosphere, causing  a
rise in global temperature.  CFCs that cause  ozone
depletion' are "greenhouse gases," with a single CFC-
113 molecule having the same estimated global  warming
effect as 14,000 carbon dioxide molecules.
                                    /
Any organic substance where at least one hydrogen atom
in the hydrocarbon molecule has been replaced  by  a
halogen atom (fluorine, chlorine, bromine, iodine, or
astatine).

Substances used as fire-extinguishing agents  and
having high ODPs.

An abbreviation for hydrochlorofluorocarbon.

An abbreviation for hydrocarbon/surfactant (intra).

Ah abbreviation for hydrofluorocarbbn.
                   /
Electronic circuits, with or without integral  passive
components, which are formed by the application of
conductive'and resistive patterns to a vitrous or
ceramic substrate.

An organic substance composed only of hydrogen and
carbon.  Gaseous or volatilized hydrocarbons  are
flammable.

A hydrocarbon whose molecule has been modified by
adding atoms other.than hydrogen and carbon,  e.g.,
alcohols.

A mixture of low-volatility hydrocarbon solvents  with
surfactants, allowing the use of a two-phase  cleaning
process.  The first phase is solvent cleaning in  the
blend and the second phase is water washing and
rinsing to remove the residues of the blend and any
.other water-soluble soils.  The surfactant ensures the
water-solubility of the otherwise insoluble
hydrocarbon.  Sometimes called semi-aqueous solvents.

An organic Substance composed of hydrogen, chlorine,
and carbon, e.g., trichloro.ethylene.
                     '• 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                                     -xviii-

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Hydrochloro-
fluorocarbon
IARC
Infra-red soldering
Isopropanol

Leadless surface
mount component


Lifetime
Low-solids flux



MEA         •  '

Metal cleaning



Methyl chloroform

Monoethanolamine



No-clean flux
OOP
 An organic  substance composed of hydrogen,  chlorine,
 fluorine, and carbon atoms.   These chemicals are less
 stable  than CFCs,  thereby having generally  lower ODPs,
 usually abbreviated as  HCFC.

 An abbreviation for International.Agency for Research
.on Cancer.

 A  method of reflow soldering  where the solder and the
 parts being joined are  heated by the incidence of
 infra-red radiation in  air,  in an inert gas, or in a
 reactive atmosphere.

 See alcohols.

 A  surface mount component (SMC)  whose exterior
 consists of metallized  terminations that are an
 integral part of  the component body.

 The folded-e lifetime is  the  time required  for the
 quantity of a substance in the atmosphere to be
 reduced to  1/e (0.368)  of its original quantity.   The
 folded-e lifetime  of CFC-113,  for example,  is about 80
 years.

 A  flux  which contains little  solid matter,  thereby
 reducing or eliminating the need for cleaning.   See
 no-clean flux.

 An abbreviation for monoethanolamine.

 General cleaning  or degreasing of metallic  surfaces or
 assemblies  generally with unspecified cleanliness
 requirements.

 See 1,1,1-trichloroethane.

 A  saponifier capable of reacting with rosin fluxes and
 fatty acids.   The  reaction products are essentially
 water-soluble.  Usually abbreviated as MEA.

 A  flux  whose residues do  not  have to be removed from
 an electronics assembly;  therefore,  no cleaning is
 necessary.   This  type of  flux is often characterized
 by low  quantities  of residues.

 An abbreviation for ozone depletion potential.
Organic acid (OA) flux  See water-soluble  flux.
Ozone
A gas  formed when  oxygen  is  ionised.   Ozone partially
filters  certain wavelengths .of UV light from the
earth.   Ozone  is a desirable  gas  in the stratosphere,
but  it is  toxic to living organisms at ground level
(see volatile  organic  compound).
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                     -xix-

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Ozone depletion
Ozone depletion
potential
Ozone layer
PCB

Pentafluoropropanol

Perchloroethylene
                  \

Perhalogenation
Photoresist
Precision cleaning
Accelerated chemical destruction of the stratospheric
ozone layer.  Chlorine and bromine free radicals
liberated from relatively stable chlorinated,
f luorinated,. and brominated products by ultraviolet
radiation in the ozone layer are the most depleting
species.

A relative index of the ability of a substance to
cause ozone depletion.  The reference level of 1 is
assigned as an index to CFC-11 and CFC-12.  If a
product has an ozone-depletion potential of 0.5, a
given weight of the product in the atmosphere would,
in time, deplete .half the ozone that the same weight
of CFC-11 or CFC-12-would deplete.  Ozone-depletion
potentials are calculated from mathematical models
which take into account factors such as the stability
of the product, the rate of diffusion, the quantity of
depleting atoms per molecule, and the effect of
ultraviolet light and other radiation on the
molecules.

A layer in the stratosphere, at an altitude of
approximately 10-50km, where a relatively .high
concentration of ozone filters harmful ultraviolet
radiation from the earth.        .      .    -
                      \
An abbreviation for printed .circuit board.

A fluorinated alcohol.

A perhalogenated chlorocarbon solvent used extensively
in industrial degreasing and dry cleaning.

An organic molecule is perhalogenated if all of the
parent hydrogen atoms in a hydrocarbon are replaced
with halogen atoms (astatine, bromine, chlorine,
fluorine, or, iodine).  For example, carbon
tetrachloride (CC14)  is  perchlorinated methane (CH^) .
Chloroform (CHC13)' is an example of a simple
chlorinated methane,  where only three of the hydrogen
atoms have been replaced.

A photomechanical product, in the form of a liquid or
a laminated dry film, used in the manufacture o.f
printed circuits.  Certain types of these products use
large quantities of ozone-depleting1 hydrochlorocarbon
solvents, usually 1,1,1-trichloroethane.
Dichloromethane is used for stripping some types.

Cleaning of high.-precision mechanical parts and
electronic sensory devices, as opposed to general
metal cleaning.  This is usually done in "clean-
rooms," with low particulate contamination, to
specific -standards.
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      -XX-    .

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POTW

Printed circuit
PWA

Reflow soldering
Rosin
Rosin flux
SA Flux

Saponifier
Semi-aqueous solvents
SMC

Solder mask (resist)



Solvent



Solvent containment
Publicly Owned Treatment Works.

A printed circuit is a component  for  interconnecting
other components.  It usually consists  of  a  metallic
conductor pattern on an organic insulating substrate.
After fabrication, it is known as a printed  circuit
board (PCB).; after assembly with  components .it  is
known as a printed wiring assembly (PWA).
[Terminology different in Europe  and  USA.]

An abbreviation for printed wiring assembly.

A method of electronics soldering commonly used with
surfac'e mount technology, whereby typically7  a paste
formed of solder powder and flux  suspended in an
organic vehicle is melted by the  application of heat.

A solid resin obtained from pine  trees.  It  is
frequently used as a flux, usually with additives.

A flux whose main constituent is  rosin.  There  are
several categories of rosin flux, often designated by
the codes R (pure rosin), RMA (rosin, mild
activation), RA (rosin,  activated usually  with  free
chloride ions), RSA (rosin, super activated).

Synthetic activated fluxes.

A chemical designed to react with organic  fatty acids,
such as rosin, some oils and greases, etc.,  to  form
water-soluble soaps.   This is a method for defluxing
and degreasing.  Saponifiers are usually alkaline and
may be mineral based (sodium hydroxide or  potassium
hydroxide) or organic based (water solutions or
monoethanolamine) .           •'

Another name for hydrcarbon/surfactant  (HCS) solvents.
The UNEP Committee recommends hydrocarbon/surfactant
(HCS) solvents as the more descriptive and accurate
nomenclature.

An abbreviation for surface mount component.

A polymeric coating applied to bare printed  circuits
which leaves only the pads or leads,  designed to be
subsequently soldered, as bare metal.

An aqueous or organic product designed to  clean a
component or assembly by dissolving and/or' displacing
the contaminants present on its surface.

Means of reducing the emission of solvents (e.g.,
CFCs) into the environment.  This technique  usually
involves improving the design and operation  of  the
equipment in which the solvent is used.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                     -xxi-

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Surface mount
component  (SMC)
Surface mount
technology  (SMT)

Surfactant
Terpene
1,1,1-trichloroethane
Ultrasonic cleaning
Vapour-phase cleaning
Vapour-phase  (conden-
sation) soldering  .
Volatile organic
compound (VOC)
Water-soluble flux
Wave soldering
A component capable of 'being attached to a PCS using
surface mount technology.'  The component may be  either
leaded or leadless.    ' .

A technique for assembling SMCs on the surface of  PCBs
and PWAs,  as opposed to inserting leads through  holes.

A chemical to reduce the surface tension of water.
Also referred to as surface-active agents.  Detergents
are made primarily from surfactants.

Any of many homocyclic hydrocarbons with the empirical
formula C10H16.   Turpentine is mainly a mixture 'of
terpenes.   See hydrocarbon/surfactant solvents.

A hydrochlorocarbon solvent with an estimated ODP  of
0.1.  Also known as methyl chloroform.

Immersion cleaning where mechanical energy formed  by
cavitational implosions close to the.surfaces being
cleaned significantly aids the cleaning operation.

A cleaning process, usually with.CFC-113 solvent or
hydrochlorocarbon solvents, where the final rinse  is
achieved by condensing solvent vapours on the parts
being cleaned.

A method of reflow soldering where the solder and  the
parts being joined are heated in the vapour of a •
perfluorinated substance whose boiling point is  <
usually in the range of 215-260°C.   In some types  of
equipment designed for this process, a less expensive
secondary vapour blanket of CFC-113 is used.

These are constituents tha-t will evaporate at their
temperature of use and which, by a photochemical
reaction under favourable climatic conditions, will
cause atmospheric oxygen to be converted into
potentially smog-promoting tropospheric ozone.*

A flux whose post-soldering residues may be removed by
a water wash.   Such fluxes are usually very active, so
adequate defluxing is an essential part of their use.
They are. also known as Organic Acid (OA) fluxes  or
inorganic acid fluxes. '

Also known as flow soldering, a method of mass
soldering electronics assemblies by passing them,   i
after fluxing,  through a wave of molten solder.
       Legally, some countries classify all organic  substances which  evaporate
at  ambient  temperatures  as  VOCs,   irrespective   of   their  ozone-promoting
properties.                       •             .
                    '•' 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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           EXECUTIVE SUMMARY:  SOLVENTS. COATINGS. AND ADHESIVES TOG


Developed Country  Progress  in Eliminating  Ozone-Depleting Solvents

      Most developed country suppliers  and consumers  of  ozone  depleting
solvents are halting 'production  and  use earlier  than  mandated  or  expected.   A
few enterprises have made unwise first  choices of alternatives and  substitutes
and are changing to better  options.

      However, significant  problems  exist  in  the  European Union (EU), where
many companies began their  investments  too late  and may  not be able  to  halt
their use prior to the  1 January 1995 EU phaseout of  production.  Furthermore,
some large companies in developed countries may have  been over-confident  that
their uses would qualify as essential and  consequently may not have  allowed
enough time for a  smooth transition.  Varying sizes of enterprises,  but
especially small-  and medium-sized ones, are  identified  in many developed
countries as possibly being unaware, unprepared,  and  financially unable to
make necessary investments  ih time to avoid chemical  shortages and price
increases that could jeopardize  their businesses.

      Procrastination in implementing alternatives and substitutes could  lead
to significant price increases .for stockpiled and recycled ODSs manufactured
prior to the phaseout.  Dramatic  price  increases  could stimulate illegal
markets in imported solvents.  In the immediate future,  shortages of ozone-
depleting substances (ODSs)  for  solvent  applications  could cause companies to
switch  to chlorinated  solvents  and/or HCFCs,> if  allowed,  because these
solvents can often be used  in existing  equipment.

Military Progress                 .

    •  In January 1994 the North Atlantic Treaty Organization (NATO) held  its
2nd international conference  on  "The Role  of  the  Military  in Protecting the
Ozone Layer".  Participants  from  Algeria,  Belarus, 'Belgium, Brazil, Canada,
Denmark,  France, Germany, Hungary,, India,  Italy,  Japan,  Kenya,  Latvia,
Lithuania,  Norway, Pakistan,  Poland, Portugal, Romania,  Russia, Spain,
Slovakia,  Sweden, Taiwan, Thailand, Netherlands,  Turkey, Ukraine, United
Kingdom,  United States,,and Uruguay attended  the  meeting.  NATO members
reported that they are  meeting or exceeding the production phaseout goals of
the Montreal Protocol and EU  members reported that they  are meeting their more
stringent goals.  Part  of the  reason for- this progress has been the leadership
of policy makers in some ministries of defence who realized that.global
environmental protection is part  of national  security'and  also  recognized that
they cannot continue to depend on chemicals that  will be unavailable or
increasingly expensive.

      Germany, Norway,  and  Sweden reported that they have  virtually eliminated
the use of ozone-depleting  solvents  in military applications.
                                                           \
      German, Swedish,  UK,  and US  participants reported  comparable progress  in
identifying and documenting alternatives and  substitutes  for civilian aircraft
maintenance including options  that provide equal  or improved cleaning,  surface
preparation,  and bonding.   The International  Cooperative  for Ozone Layer
Protection (ICOLP) announced  plans to invite  U.S. .Environmental Protection


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 Agency (EPA)  and the National Aeronautics and Space Administration (NASA) to
 join their global project to phase out ODSs in aerospace operations.   NASA and
 U.S. EPA are  considering the proposal.

       The meeting resulted in several recommendations being made to NATO:

       •      Share information on critical uses (e.g. gaseous and liquid oxygen
             systems, guidance systems, rocket motors) via electronic data-
            bases, publications, workshops and informal working groups.
       •      Foster and support streamlined universal qualification processes
             and procedures.
       •     Revise the existing military documentation.
       •      Further investigation, certification,  and publication of
             alternatives and substitutes for unresolved applications including
             critical adhesive bonds in rocket motor manufacturing, cleaning
             and verification of gaseous and liquid oxygen systems, and other
             specific precision cleaning such as gyroscope bearings in space
             systems that must operate for many years without maintenance.
       •      Speed awareness  and introduction of proven technologies by
            utilizing "tiger teams" of experienced engineers and scientists to
            help implement these technologies in military applications.
 Developing Country Progress:

       In some cases,  technology cooperation with developing countries has
 already been highly successful or has prepared countries to take prompt action
 once incentives and financing are in place.  Examples include Mexico,
 Thailand,  Turkey,  and Malaysia. .An important conclusion from investigations
 of solvent use in developing countries is that enterprises must be motivated
 and prepared to accept new technology.  This motivation can result from
 government regulation, a clearly articulated industry phaseout strategy,  price
 increases, product shortages,  or supply uncertainty for ozone-depleting
 substances.   Some technology cooperation efforts have been prematurely
 attempted in countries where enterprises and national governments were not
 prepared,  and as a consequence little actual investment progress has been
 made.                                            :

       Some regional and national conferences and workshop's have not been as
 successful as they could have been because the preconditions for change had
 not been met.   The Committee recommends that conference planners more
 completely involve local industry, industry associations,  and chambers.of
 commerce in the planning and that they determine whether the preconditions for
 change are in place.   If it is determined that a conference is useful,
•conferences  should be organized and announced far in advance.  It has. been the
 experience of the Committee in developed and developing countries that
 representatives of small- and medium-sized solvent-using enterprises do not
 travel long-distances for meetings based on general presentations.  They are
 short  of funds and their manufacturing engineers are very busy.  This makes
 ensuring the presence of a motivational framework all the more important.

       One  problem common to all countries, but especially'developing
 countries,  is that domestic small- and medium-sized enterprises that use ODSs
 are difficult to identify,  may not welcome government officials, and may not
 be easy to convince that a change is necessary.  .It is likely that many of


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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such users will only make changes when the price increases, when shortages
develop, when domestic regulations are in place, or when multinational
companies require suppliers to phaseout.

Concerns of unannounced changes in speciality products:

      The Committee cautions that manufacturers may eliminate ODSs from
products without notifying customers.  There is the possibility that  the
manufacturer may not appreciate that their product is used in a particular
application where the ODSs provided a necessary performance characteristic
that is not duplicated by the reformulated product.  Use of such reformulated
materials and products under these circumstances could be costly or dangerous
to life and health.  The solution is for manufacturers of speciality  products
to better communicate to end-users, changes in product ingredients and to
cooperate with end-users on performance testing of the new products.

      Some Parties may have interpreted process agent use of controlled
substances as subject to phaseout.  Other Parties may have interpreted such
use as feedstock not subject to the phaseout.  In 1994 the Committee  was
unable . to recommend exemptions for process agent use under the Essenti'al Use
Criteria.                                       .        •

      At the October 6-7, 1994 Meeting of the Parties to the Protocol, it was
decided:

      "...for an interim period of 1996 only, (Parties may) treat chemical
      process agents in a manner similar to feedstock, as recommended by the
      Technology and Economic Assessment Panel, and take a final decision on
      such treatment-at their. Seventh Meeting;"(Decision VI/10)

The Parties requested the .Technology and Economic Assessment Panel (TEAP)-:

      To identify uses of controlled substances as chemical process agents, to
      estimate emissions and ultimate fate, and to evaluate control
      technologies;


      To evaluate alternative process agents or technologies or products
      available to replace controlled substances in such uses; and to

      To report findings not later than March 1995.  The Panel has asked the
      government of Sweden to organize and finance a special working  group to
      complete this work.
1994 Nominations for Essential Uses

      The Committee reviewed nominations from Austria, Belgium, Canada,
Denmark, European Commission (EC)', Finland, France, Germany, Greece,  Ireland,
Italy, Japan, Netherlands, Norway, Sweden, Switzerland, United Kingdom,  and
the United States.  In all but laboratory and analytical uses and  Space
Shuttle rocket motor manufacturing the Committee was unable  to recommend the
nominations because there are technically and economically feasible
alternatives arid substitutes and/or because controlled substances  are
available in sufficient quantity and quality from'existing sources.   The


                    * 199A UNEP SOLVENTS. COATINGS, AND ADHESIVES REPORT *
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 Committee  also  found  that many  requests  were  insufficiently supported with
 technical  data.

 HCFC

      Few  large scale current uses  of HCFCs have been reported for solvents,
 coatings,  or adhesives.  In  the near term HCFCs may be necessary as transition
 substances  in some  limited and unique applications including:

      •     cleaning  delicate materials  such  as cultural  heritage and archival
            property
      •     cleaning  assemblies or  components with sensitive materials or
            particular  soils
      «     cleaning  certain oxygen systems
      «     cleaning where explosive or  flammable conditions are possible
      «     as a carrier of oil in  precision  applications.

      In6countries where HCFCs are  prohibited, enterprises  may,  in certain
 specific cases, select  perfluorinated carbons (PFCs)  as an  adjunct to
 specialized cleaning systems.  PFCs have extremely long atmospheric lifetimes
 and have potent global  warming potentials (GWPs) and  should therefore be
 avoided where ppssible.

      The  Committee does not recommend the use of HCFC-141b to replace 1,1,1-
 trichloroethane as a solvent.  A recommendation is not possible  because HCFC-
 141b has an ozone-depletion potential (ODP) comparable to 1,1,1-
 trichloroethane and is  not technically suitable for many  cleaning
 applications.                        ...

      It is estimated that HCFC-lAlb and HCFC-225 together  will  not replace
 more than  1 percent of  global.CFC-113 uses unless HCFC-225  becomes a
 substitute for CFC-113  in dry cleaning,  which could increase use  to
 approximately 5 percent.  In some countries with active HCFC sales efforts,
 approximately 5 percent of CFC-113  solv.ent use (excluding dry-cleaning which
 may increase use) may be replaced with HCFC-141b.  It  is  estimated that HCFCs
 may replace 1-5 percent of 1986 CFC-113  and 1,1,1-trichloroethane use as•
 transitional substances and where no alternatives or  substitutes  are currently
 available.

      The Committee cautions that there  may be essential  uses  of  very small
 quantities of ozone-depleting solvents that are not yet identified by the
 Committee, national governments, product distributors, and  possibly the
manufacturers themselves.  However, it is expected that these  uses will be
 identified as the accelerated phaseout in the EU is implemented  and as
production is halted.   Stockpiled and recycled sources may  be  adequate to
 supply these uses.

 PRICE INCREASES AND SHORTAGES OF OZONE-DEPLETING SOLVENTS

      CFC-113 is produced primarily as a solvent with  certain amounts sold as
a feedstock for production of HFC-134a and some plastics.   When  CFC-113 sales
 in solvent uses are halted in the EU in  1995, and in  all  developed countries
by 1996, the market may not be sufficient for developed country  manufacturers-
 to supply developing country markets.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      CFC-113  is  currently  manufactured in two  developing countries  --  China
and India  -- and  production facilities  in South Korea  and Taiwan are believed
to be currently inactive.

      Since 1,1,1-trichloroethane  is  produced as a  feedstock for HCFC-141b  and
HCFC-142b, it  will be more  readily available  than CFC-113 after  1996 for
export to  developing countries  for their domestic needs,  subject to  Protocol
restrictions.

      It is the consensus of the Solvent,  Coatings  and Adhesives Technical
Options Committee that  quality  grades of CFC-113 and •!,1,1-trichloroethane
will be in uncertain supply after  1996  and that it  will be prudent for
enterprises in developing countries to  move quickly to reduce  and eliminate
dependence on  these chemical substances when  cost-effective options  are
available.  European, Japanese, and U.S.  chemical manufacturers,  distributors,
and customers  may have  residual chemical supplies produced under national
Protocol quotas or under Basic  Domestic Needs quotas that may  be marketed to
developing countries if sales are  less  than expected in their  developed
country markets.  This  oversupply  is  less  likely in the United States where
taxes on stored ozone-depleting substances discourage  oversupply.

      A variety of alternative  substances  and technologies are currently in
use or under development to facilitate .the phaseout of CFC-113 and 1,1,1-
trichloroethane.  These alternatives  include no-clean  technologies,  aqueous
and semi-aqueous  cleaning,  other hydrocarbon solvents, non-ozone-depleting
chlorinated solvents, HCFCs, perfluorocarbons,  and  a growing number  of non-
solvent cleaning  processes.-

      No-clean technologies represent the  optimum alternative  and have been
applied in an  increasingly  large number of electronics manufacturing
applications in recent  years.   Nevertheless, research  and testing of no-clean
manufacturing  processes is  ongoing in the  hope  of making  them  viable
alternatives in a wider variety of uses.   Second to no-clean with respect to
environmental  protection is aqueous or  semi-aqueous cleaning.  The major
drawbacks  of these alternatives may be  high energy  consumption and wastewater
treatment  costs,  depending  on the  process, requirements,  and legislation.

      HCFCs, though their use is transitional,  are  important alternatives to
CFC-113 and 1,1,1-trichloroethane  solvent  use in applications  for which no
other viable alternative exists.   Because  of their  lower  ozone-depletion
potential  (ODP),  HCFCs  with a short lifetime are  preferred tp  those  with
longer lifetimes.  The.ODP  of all  HCFCs is lower  than  the  ODP  of CFC-113.
However,  HCFCs should be used as substitutes for  1,1,1-trichloroethane only  if
the ODP of.the HCFC substitute  is  lower than 0.10 and  if  their emissions are
controlled using  the best available technology.   In addition,  the 1992.
Copenhagen Amendments to the Montreal Protocol  require that .production and
consumption of HCFCs, as defined in the Protocol  (Annex III  G. Article 2F of
UNEP/OzL.   Pro. 4/15), must  be reduced by 99.5%  by 2020 and completely phased
out by 2030.   Thus, HCFCs are a valid alternative in certain limited
applications while other, long  term alternatives  are being developed.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                                SECTOR PROGRESS

Electronics Cleaning

      The electronics industry, which was heavily dependent  on  ozone-depleting
solvents until recently, is fortunate to have  the widest  range  of  substitute
materials and processes available.  There is no technical reason why  any
company, large or small, in a developed or developing nation, should  not be
able to move away from such solvents immediately.  Economic  considerations,
reported in previous editions (UNEP 1989, 1991), have shown  that most
substitute processes for this industry are less costly  to run and, most often,
give improved technical quality.  On the other hand, relatively large
investment capital is sometimes required to obtain the  required results and
this could be an obstacle, especially for small companies manufacturing "hi-
tech" electronics.

      To substitute for CFC-113 in defluxing,  there  is  a  large  choice of
processes, equipment, and materials commercially available for  production
units of all sizes.  Where there are no technical specifications that require
post-solder cleaning, "no-clean" techniques are often the most  economical.
This technique is recommended where the reliability  criteria can be met.
Where cleaning is a requirement, the use of water-soluble chemistry has
generally proved to be preferable to most other processes, although it is not
a universal solution.  There is an adequate choice of other  techniques where
neither of these can be applied.

      The Solvents, Coating and Adhesives Technical  Options  Committee do not
recommend the following processes in electronics manufacture for funding under
the provisions of the Montreal Protocol Multilateral Fund:

•     HCFC-141b for defluxing printed circuits
•     Vapour-phase reflow soldering
•     Vapour-phase drying of heavy organic solvents  using PFCs
•     Vapour-phase drying of water using MFCs or PFCs.
Precision Cleaning

      Precision cleaning applications are characterized by the high level of
cleanliness required to maintain low-clearance or high-reliability components
in working order.  They are used in a variety of manufacturing industries,
such as in aerospace, microelectronics, automotive, and medical.  Several
factors define' the applications where a precision cleaning process is
required.   Some of these factors are:

      •     high standards for the removal of particulates or organic residue
      •     components constructed of chemically-sensitive materials
      •     components with physical limitations, such as geometry or
            porosity, which limit the ability to remove entrapped fluids like
            water
      •     high-cost components or components requiring high-reliability
                  »
      CFC-113 and 1,1,1 -trichloroe.thane have evolved as the preferred solvent
cleaning method in precision cleaning because of their chemical  inertness,  low
toxicity,  non-flammability, low surface tension, and low water solubility.


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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However, to eliminate CFC-113 and 1,1,1-trichloroethane use, a number of
companies have tested and implemented alternative cleaning methods.  Possible
alternatives include solvent and non-solvent options.  Solvent options  include
other organic solvents  (such as alcohols and aliphatic hydrocarbons),
perfluorocarbons, HCFCs and their blends, and aqueous and semi-aqueous
cleaners.  Non-solvent  options include supercritical ^luid cleaning, UV/Ozone
cleaning, pressurized gases, and plasma cleaning.  Solvent ,use may also be
reduced by controlled planning of repetitive or multiple cleaning operations.

Metal Cleaning

      Metal cleaning is a surface preparation process that removes organic
compounds such as oils  and greases, particulate matter, and inorganic soils
from metal surfaces.  Metal cleaning prepares parts for subsequent operations
such as further machining and fabrication, electroplating, painting, coating,.
inspection, assembly, or packaging.  Parts may be cleaned multiple times
during the manufacturing process.

      The control approaches available for metal cleaning operations include
solvent conservation and recovery practices and the use of.alternative
cleaning such as solvent blends, aqueous cleaners, emulsion cleaners,
mechanical cleaning, thermal vacuum de-oiling, and no-clean alternatives.
Alternatives to CFC-113 and 1,1,1-trichloroethane must be selected and
optimized for each application given the varying substrate materials, soils,
cleanliness requirements, process specifications, and end uses encountered in
metal cleaning.

Dry Cleaning

      Dry cleaning enables the cleansing and reuse of fabrics that.cannot be
cleaned by alternative methods.  The inherent environmental friendliness of
restoring freshness to  soiled articles and garments is matched by extreme
efficiency in terms of  solvent and energy use in the dry cleaning process
itself.  Organic solvents are used to clean fabrics because, unlike water,
they do hot distort some'natural and synthetic fibres.  Water cleaning of many
materials can affect the stability of fabric, lining, and interlining and may
cause stretching or shrinkage.

      A number of solvents can be used as alternatives to CFC-113 and 1,1,1-
trichloroethane in dry  cleaning operations.  Perchloroethylene,  the most
widely used dry cleaning splvent, has been used in this application for over
30 years, during which,  time the systems for its safe use have become highly
developed.   The flammability of petroleum solvents effectively precludes their
use in shops, although with proper precautions, they can be a substitute for
CFC-113 on many fabrics.  Petroleum solvents include white spirit, Stoddard
solvent, hydrocarbon solvents, isoparaffins, n-paraffin, etc.  A number of
HCFCs and HCFC blends are currently available commercially  for use in solvent
applications.  These include HCFC-123, HCFC-141b, and HCFC-225.   These HCFCs
have good stability, appropriate solvency, and non-flammability and some HCFCs
are suitable for cleaning those delicate fabrics that currently depend on CFC-
113.  It should be noted, however, that HCFCs are transitional alternatives
subject to a phaseout under the'Montreal Protocol by the year 2030.  Other
classes of chemicals such as isoparaffins, solvents derived from sugar cane,
and hydrocarbon/surfactant blends'are theoretically possible alternative dry
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     ES-7

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 cleaning  solvents.  More  research, however,  is  necessary to determine their
 feasibility  for  dry cleaning.

 Adhesives

       1,1,1-Trichloroethane  is  used  as  an adhesive  solvent because it is non-
 flammable, dries  rapidly,  does  not contribute to  local  air pollution,  and
 performs  well  in many  applications,  particularly  foam bonding.   The rubber
 binders used in  1,1,1-trichloroethane adhesives are soluble in  other solvents,
 such as acetone,  ethyl acetate, heptane,  and toluene.   Although there has been
 a general trend  in the U.S.  and Western European  adhesives industries to
 replace organic  solvent-based adhesives with solvent-free types,  one
 alternative  is to return  to  earlier  solvent  formulations.

       Some adhesives use  water, in lieu of organic  solvents,  as the primary
 solvent.   Recent  literature  on  water-based adhesives suggests that there is
 still  much debate about the  overall  effectiveness of water-based adhesives for
 many end  uses.

       The Committee D-14  of  the American Society  for Testing and Materials
 (ASTM) defines a  hot melt adhesive as one that  is applied in a  molten state
 and forms a  bond upon  cooling to  a solid state.   Hot melt Pressure-Sensitive
 Adhesives (PSAs)  now compete with water-based acrylics  in outdoor
 applications.  They have  been used on paper  labels  for  indoor applications
 since  1978.

       Radiation  curing is a  production  technique  for drying and curing
 adhesives through the  use of radiant energy  such  as ultraviolet (UV),  infrared
 (IR),  electron beam (EB),  gamma,  and x-rays.  Radiation cured adhesives  are
 especially well  adapted for  pressure sensitive  tapes.   One drawback is that
 adhesive  curing  is only possible  in  the "line of  sight" of the  radiant energy.

       One way to  lower volatile organic compound  (VOC)  emissions  when using
 solvent-based adhesives is to increase  the percent  solids in .the  formulation.
 High solids  adhesives  have good performance  characteristics,  including initial
 bond strength comparable  to  that  of  30  percent  solids adhesives in medium and
 high demand  applications  and can  be  applied  using existing equipment at  normal
 line speeds  with  minor modifications.   In other application areas,  such  as
 bonding rubber assemblies, high solids  adhesives  have not been  as successful.

       One-part epoxies, urethanes, and  natural  resins are often supplied as
 powders that require heat to cure.   Powders  are only used for non-pressure-
 sensitive applications.   One advantage  of the powder form is  that no mixing or
 metering  is  necessary.  However,  powders  must be  refrigerated to  maximise
 shelf  life.

      Moisture cure adhesives and reactive liquids  can  be applied as -100
 percent non-volatile solid and  liquid systems.  These adhesives are composed
 entirely  of binding substances, modifiers, and  fillers  (i.e., they have  no
 carrier or solvent).   Moisture  cure  adhesives cure  upon exposure  to the
humidity  in  the ambient air; this type  of adhesive  requires application  in a
humid environment and  might  not work well in dry  climates.   Some  two-component
 adhesives use reactive solvents which form part of  the  cured mass and thus do
not depend on evaporation.   In  use,  one solution  consisting of  an elastomer
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     ES-8

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colloidally dispersed  in a monomer  is  cured by  a  second  solution  through  a
free radical chemical  polymerisation,  thereby creating the bond  .

Coatings and Inks

      1,1,1-Trichloroethane  is used by manufacturers, printers, and users of
protective and decorative coatings  and inks.  CFC-113 use in  the  production  of
coatings or inks is negligible.   In coatings, 1,1,1-trichloroethane is used
alone or combined with other solvents  to solubilize  the  binding substance
which is usually composed of resin  systems such as alkyd, acrylic, vinyl,
polyurethane, silicone, and  nitrocellulose resin.  Inks  are used  to print
items ranging from wallpaper to dog food bags to  beverage bottles and.cartons.
Many of these uses involve the application of coloured ink to a film  (or
laminate) in the flexible packaging industry.

      Some coatings contain  water rather than organic solvents.   Recent
advances in water-based coating technology have improved the  dry-time,
durability, stability, adhesion,  and application  of  water-based coatings.
Primary uses of these  coatings include furniture,  electronics in  automobiles,
aluminum siding, hardboard,  metal containers,. appliances, structured  steel,
and heavy equipment.   Water-based inks for flexographic  and rotogravure
laminates have been successfully  developed and  have  overcome  technical hurdles
such as substrate wetting, adhesion, colour stability, and productivity.

      Although high-solid coatings  resemble conventional solvent  coatings in
appearance and use, high-solid coatings contain less solvent and  a greater
percentage of resin.   High-solid  coatings are currently  used  for  appliances,
metal furniture, and'a variety of construction  equipment.  The finish of  high-
solid coatings is often superior  to that of solvent-based coatings, despite
the fact that high-solid coatings require much  less  solvent than  dp solvent-
based coatings.                              -

      Powder coatings  contain the resin only in powder form and thus  have no
solvent.  While powder coatings were first used only for electrical
transformer covers, they are now  used  in a large  number  of applications,
including underground  pipes, appliances, and automobiles.

      Ultraviolet light/Electron  beam  (UV/EB)-cured  coatings and  inks have
been used in very limited applications over the last 20  years, but their  use
has seen a dramatic increase in recent years.   Several of the markets in  which
UV/EB-cured coatings and .inks have  been used 'more  frequently  in recent years
are flexographic inks  and coatings, wood furniture and cabinets,  and
automotive applications.  One major limitation  to  the use of UV/EB-cured
coatings and inks is outdoor durability.  This  is  an especially important
consideration in automotive  applications.

Aerosols Solvent Products

      1,1,1-Trichloroethane  functions  as either an active ingredient  (e.g.,
degreaser or cleaner)  or as  a solvent  in aerosol  product formulations.  Though
most of the aerosol applications  traditionally  used  1,1,1-trichloroethane as
their solvent, there are a small  number of products  which made use of CFC-113  .
as well.  Most aerosol products currently employing  CFC-113. and.1,1,1-
trichloroethane can be reformulated with alternative compounds.   Except for
water, some HGFCs, and non-ozone-depleting chlorinated solvents (e.g.,


                    * 1994 UNEP  SOLVENTS,  COATINGS, AND ADHESIVES REPORT *,
                       .           ,   ES-9

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trichloroethylene, perchloroethylene,.methylene  chloride),  all  of the
substitute solvents currently available  are more flammable  than 1,1,1-
trichloroethane.  The  flammability  is  also a  function  of  the  propellant;
butane and propane being more flammable  than  carbon  dioxide,  nitrous oxide  or
the traditional CFC-ll/CFC-12 mixture.

      Alternative solvents'currently exist for virtually  all  aerosol solvent
applications of CFC-113 and  1,1,1-trichloroethane.   However,  while some  of
these alternatives are functional,  they  are considered to be  less than optimal
for a variety of reasons.  For example,  in applications where a strong solvent
is required, but the use of  a flammable  solvent  would  pose  serious safety
risks, substitutes may include only HFCs, HCFCs,  and chlorinated solvents.
While these solvents would be functional, HCFCs  contribute  to ozone-depletion,
and chlorinated solvents are toxic  and may pose  health risks  to workers  and
users of a product.

      CFC-113 and 1,1,1-trichloroethane  use in aerosols can also be reduced if
alternative means of delivering  the product are  developed.  Two examples of
these alternative methods are:   (1) a  manual  "wet-brush"  (recirculating
liquid) system, as a substitute  for aerosol brake cleaners  used in repair
shops, and (2) increased use of  professional  dry cleaning services as a
substitute for the use of aerosol spot removers.

Other Solvent Uses of  CFC-113, 1,1,1-Trichloroethane,  and Carbon Tetrachloride

      Some amount, in most cases relatively small quantities, of CFC-113,
1,1,1-trichloroethane, .and carbon tetrachloride  are  employed  in a number of
industry and laboratory applications.  The application areas  include drying of
components, film cleaning, fabric protection, manufacture of  solid rockets,
laboratory testing and analyses, process solvents, semiconductor
manufacturing, and others.

      The Committee 'consensus is that  by 1996, in-accordance  with the Montreal
Protocol, most of the CFC-113, 1,1,1-trichloroethane,  and carbon tetrachloride
used for these applications  can  be  replaced by the alternatives.

      In the applications of laboratory  analyses and in the manufacture  of  a
specific large scale solid rocket motor, the  Parties have granted an exemption
for continued use of specified ozone-depleting solvents for.1996 and 1997.
The exemptions are subject to review and1alternatives  are being investigated.

      In the case of use of  ozone-depleting substances as process chemicals,
there are also a number of alternatives  identified in  this  report.  In
addition, an in-depth review of  alternatives  is  planned for completion and
presentation by the Technical and Economic Assessment  Panel' to  the Parties  by
early 1995.

PROGRESS IN ELIMINATING ODS  FROM ROCKET MOTORS

      Ozone Depleting Substances (ODSs) have  been routinely used globally for
decades in the manufacture of space launch vehicle solid  ropket motors (SRMs).
The primarily ozone-depleting solvents used are  1,1,, 1-trichloroethane (TCA  or
methyl chloroform) and CFC-113.  These substances are  used.because of their
excellent cleaning properties, low  toxicity,  chemical  stability and non-
flammability.


                   * 1994 UNEP  SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                                     ES-10

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       In the United States, large solid rocket motors (SRMs) are used to
 launch into space communication, navigational and scientific satellites and
 the manned Space Shuttle orbiters.  Large SRMs include the existing Titan IV
 SRM as well as its upgraded version calle^d the SRMU and the Space Shuttle f
 redesigned solid rocket motor (RSRM).
                                   /                               __        ,
       Despite these technical safety and reliability challenges, the SRM
 industry has successfully tested, approved,  and implemented significant ODS
 elimination.  Since 1989, the four US  manufacturers of large SRMs have
 eliminated over 1.6 million pounds of  ODS use per year.   Current (1994) ODS
 usage is less than 48 percent of the use in 1989.  Usage in 1995 is estimated
 to be less than 22 percent of 1989,  and manufacturers have committed to
 complete elimination of ODSs within the next few years.  •

 Update on the Essential Use Applications

       NASA/Thiokol was granted an essential  use production exemption for 1996
 and 1997.   NASA/Thiokol have proceeded with  their phaseout and are ahead of  '
 schedule for eliminating non-essential uses  and investigating additional
 alternatives and substitutes.   However, at this time NASA/Thiokol has not
 identified any acceptable substitutes  that would reduce  their essential use
 below the previously calculated amounts..

       The Solvents,  Coatings,  and Adhesives  TOC reported in the March 1994
 Report that it was likely that all manufacturers of solid rocket motors use
 ODSs.   The Committee has confirmed that other U.S.  and European solid rocket
 motors use these substances and that these organizations are expected to
 nominate additional" essential uses by  January 1,  1995 for decision in 1995.

       The U.S.  Titan program is working to completely eliminate the use of
 ODSs and has invested substantial resources  in successfully developing
'alternatives to ODS use.  The prime contractor and the major manufacturers of
 Titan IV vehicle components will reduce all  ODS -use by 99 percent, -from 1.33
 million kg in 1989 to 9,200 kg in 1996.  Four small-quantity ODS .uses are
 critical to the success of the Titan SRMU.  These are-(1) surface preparation
 to ensure effective bonding of the internal  insulator-to the composite case,
 (2)  surface preparation to ensure effective  attachment of breather cloth to
 the  insulator to permit uniform curing, (3)  surface preparation to ensure
 effective bonding of the propellant to the insulator, and (4) dispersing
 propellant cure catalyst during propellant mixing.   The  quantity of ODS
 necessary to complete SRMU.manufacture for the final nine flight sets is 3,660
 kg per year or less for 1996 through to 1999.

     °  Both CFC-113 and TCA are used in the European Ariane Espace Programme.
 Efforts to find substitutes for these  programmes concern CRYOSPACE for liquid
 rocket engines and Societe Europeenne  de Propulsion (S.E.P.) for solid motors.

       The Japanese space rocket industry currently uses  CFC-113 and TCA but
 expects to phase out the uses by the end of  1995.  Latest achievements include
 the  solid rocket booster (SRB) for the H-II  launch vehicle which is capable of
 launching a.2 Ton satellite to Geosynchronous orbit.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      ES-11

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 Cleaning of Oxygen Systems

       In January 1994 NATO identified the cleaning of oxygen systems as one of
 the  most difficult challenge facing military and aerospace applications.   In
 Fall 1994,  the  International Cooperative for Ozone Layer Protection (ICOLP),
 Aerospace Industry Association (AIA),  U.S.  EPA,  'National Aeronautical and
 Space Administration (NASA)  and the U.S.  Air Force convened a special workshop
 on cleaning of  oxygen systems without ozone-depleting solvents.

       Oxygen systems include:  life support systems such as diving,  totally
 encapsulated suits,  emergency breathing devices, fire & rescue backpacks,
 submarine,  aircraft,  manned spacecraft,  and medical applications;  propulsion
 systems  such as liquid rocket motors;  industrial systems such as chemical
 production;  and other unique systems and customer products such as welding
 equipment.

       Oxygen systems must be kept clean because  organic compound
 contamination,  such as hydrocarbon oil,  can ignite easily and provide a
 kindling chain  to ignite surrounding materials.   Contamination can also
 consist  of particles that could ignite or cause  ignition when impacting other
 parts of the system.   Risk is increased by the  typical proximity of oxygen
 systems  to very large quantities of fuel materials,  and the common necessity
 of locating oxygen systems in confined spaces with difficult or impossible
 access and egress (e.g-.  space ships, submarines, aircraft, .and. surf ace ships).
    .   Examples  of  the  challenges  presented by these applications  include the
 cleaning  of the space  shuttle  external fuel tank,  cleaning of aircraft carrier
 liquid oxygen plants,  cleaning of installed submarine and transport aircraft
 high  pressure oxygen systems,  and the  gauges and instrumentation  associated
 with  each.   Examples of devices typically cleaned in these systems  include
 tubing, gauges,  regulators,  valves,  and metering devices.   It is  usually most
 effective to clean oxygen equipment  at the piece part level in a  proper
 facility.   It is more  difficult to clean oxygen equipment in aircraft and ship
 equipment in place with difficult accessibility and temperature extremes.
 Additional  challenges  occur  in many  other industrial oxygen systems such as
 those used  in production' and transfer  of both gaseous and liquid  oxygen,  in
 medical applications,  and in welding.   Cleaning of equipment used in the
 oxygen production  industry involves  unique challenges such as compatibility
 with  aluminum heat exchangers.

       Solvents  such as  non-ozone  depleting chlorinated solvents and
.hydrocarbons often clean satisfactorily,  but all have -environmental or
 toxicity  concerns,  and  some  have  flammability concerns.

       Aqueous cleaning  options have  been successfully developed and   .  •
 implemented for many oxygen  system cleaning situations.   For example-,  Lockheed
 uses  aqueous processes  in the  manufacturing and maintenance of aircraft and
 missile oxygen  systems,  the  Air Force  uses aqueous cleaning for some aircraft
 oxygen system maintenance, NASA/Kennedy Space Center uses aqueous solutions
 for cleaning oxygen bulk storage  and transfer systems for rocket  motors,  and
.the U.S.  Navy uses aqueous cleaning  processes for cleaning the tubing in
 oxygen systems  on  ships and  submarines.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     ES-12

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      Isopropyl alcohol  (IPA) is being used by Lufthansa German Airlines  to
clean the oxygen systems in their commercial aircraft fleet.  Sweden has
reported using a solvent blend for oxygen system cleaning consisting of 95%
ethanol.     ,                                        '

      Some parts of oxygen systems can be changed to simplify or avoid the
necessity of cleaning or they can be adapted to' allow aqueous-cleaning.

      Some, oxygen system components still depend on  CFC or chlorinated solvent
cleaning because current alternatives and substitutes are not technically
suitable.  In other cases, rigid specifications and  requirements may need to
be changed from prescriptive to performance standards to allow technically
feasible solutions to be used.              '

      This Report includes case studies of successful elimination of ozone -
depleting solvents which discuss the evaluation and  implementation.of
materials, alternative technologies, and processes.  The following are
included in Chapter 11:  Allied Signal (evaluation of aqueous saponifie.rs) , .
AT&T Bell Labs (non-ODS -alternatives including no-clean soldering), Beck
Electronics (alternative solvents and design of cleaning equipment), Ford
Motor Company (no-clean soldering), Hitachi (non-ODS alternatives), Honeywell
.(non-ODS alternatives), IBM Corporation (no^clean soldering), Japan Industrial
Conference on Cleaning (information dissemination),  Lockheed Sanders Company
(company phaseout efforts), Miljoministeriet (hydrocarbon dry cleaning),
Minebea Company (aqueous cleaning of ball bearings), National Semiconductor
(company phaseout efforts), Naval Aviation Depot. Cherry Point (hand-wipe
cleaning). Northern Telecom (company phaseout efforts), Robert Bosch
Corporation (aqueous cleaning), Rockwell International (low-residue flux),
Seiko Epson Corporation  (alternatives to ODSs), Singapore Institute of
Standards and Industrial Research (ODS-free certification of businesses),
Swedish EPA (country-wide phaseout efforts), Toshiba Corporation (vinyl-
copolymer masking agent), U.S. Air Force Aerospace Ciuidance and Metrology
Center  (aqueous & non-aqueous alternatives), Vibro-Meter, SA  (water-based
cleaning).                   '                      • . .      .

Total Equivalent Warming Impact (TEWI)

      Total Equivalent Warming Impact • (TEWI) provides an important tool in the
selection procedure for alternative cleaning and drying technologies.
However, TEWI must not be the only criterion when selecting the cleaning.
drying,  or other technology for a manufacturing process.  The Alternative
Fluorocarbons Environmental Acceptability Study (AFEAS) has provided a
methodology to calculate. TEWI for wide range of available systems.

      The selection of the. best technology to displace CFC-113 or 1.1,1-
trichloroethane (methyl chloroform) must be specific to the intended
applications and will represent a trade-off or balancing of several key
parameters:   worker safety (toxicity or flammability concerns), investment,
operating costs,  energy efficiency and reliability.  It must also consider a
series of environmental issues (discharges to water  or landfill, local.
environmental air quality (smog) and global impact).

      This report has evaluated one of the selection parameters. TEWI. for a
number of systems.  A summary of the key findings follows.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     ES-13

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•     Solvent losses  from  the  cleaning  equipment  are  potentially lower than
      assumed in the  1991  study.,  resulting  in  lower calculated contributions
      to TEWI.  This  reduction in emissions  is  possible  through the adoption
      of enhanced vapor recovery  and  improved/novel approaches to materials
      handling  (e.g.,  freeboard dwell).   In  some  cases,  the  above technologies
      can be retrofitted to very  modern existing  equipment,  with results
      almost comparable to new equipment.  However, such equipment will
      require careful  operation and maintenance to sustain low emission rates.

      The no-clean systems used for the  manufacture of printed wire assemblies
      have the potential for the  lowest  TEWI.   For metal cleaning,
      chlorocarbon-based systems  (e.g.,  PCE, TCE) have the potentially lowest
      TEWI.  However,  these chlorinated  solvent systems  may  be subject to
      various national, regional  and/or  local regulations or emission limits
      that may severely limit  the use of these  chemicals for cleaning
      applications.

     • The PFC system  studied has  the highest TEWI.

•     While they use more energy  per unit of work (throughput),  aqueous,  semi-
      aqueous and alcohol systems  generally have been shown  to have a lower
      TEWI than HCFC and HFC-based systems because emissions from aqueous,
      semi - aqueous, and alcohol systems  do not  contribute to global warming.

      In .the case of HCFC/HFC/PFC-based  systems,  the  direct  effect  caused by
      emission of the  chemical, represents from 40 percent to over  90 percent
      of the calculated contribution to  potential global warming.

      Future study should assess,  the effects of variations in equipment and
practices'on TEWI and  estimate- implementation time for alternative  systems  in
developing countries.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     ES-14

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                                   CHAPTER 1

                                  INTRODUCTION
1.1   BACKGROUND

      In response  to  the  growing  scientific  consensus  that  chlorofluorocarbons
(CFCs) and halons  would ultimately  deplete the  ozone layer,  the  United  Nations
Environment Programme  (UNEP)  in 1981 began negotiations  to  develop
multilateral policies  for protecting the  ozone  layer.  These  negotiations
resulted' in the Vienna Convention for  the Protection of  the  Ozone Layer in
March -1985.  The convention provided a framework  for international  cooperation
in research, systematic observation, and  information exchange.   In  September
1987, 24 nations including the United  States, Japan, the  Soviet  Union,  and
members of the European Community signed  the Montreal  Protocol on Substances
That Deplete the Ozone Layer  (hereafter referred  to as "the  protocol").  As of
February 1994, 132 nations and the  European  Community  had ratified  the
Protocol (see Table 1-1).  These  countries represent virtually all  of the
world's consumption1 of CFCs and halons.  The Protocol, which entered into
force on January 1, 1989, limited consumption of  specified  CFCs  to  50 percent
of 1986 levels by.the  year 1998 and called for  a  production  freeze  of
specified halons at 1986  levels starting  in  1992.  Table  1-2  lists  CFCs,
halons,"and other  substances  controlled under the Protocol.

      Shortly after the 1987  Protocol  was negotiated,  new scientific evidence
conclusively linked CFCs  to depletion  of  the ozone layer  and  indicated  that
depletion had already  occurred.   Consequently,  many countries called for
further actions to protect the ozone layer by expanding and  strengthening the
control measures of the 1987 Montreal  Protocol.   In June  1990, the  Parties to
the Montreal Protocol  met in London and agreed  to Protocol adjustments
requiring more stringent  control  measures on the  CFCs  and halons than those
listed in the original agreement.   Amendments'placed further  control measures
on other ozone-depleting  substances including carbon tetrachloride  and  1,1,1-
trichloroethane.   In April 1991 the National Aeronautics  and  Space
Administration (NASA)  concluded that depletion  of the  ozone  layer over  the
past decade has occurred  at a rate  faster than  previously estimated.  The four
to five percent depletion over populated northern latitudes  since 1978  led
many countries, to propose' more stringent phase-out schedules  than those
proposed at the London meeting of the  Parties to  the Protocol.   As  a result,
the Parties to the Protocol met in  Copenhagen in  November 1992 and  agreed to
further amendments and adjustments  requiring even more stringent control
measures on all controlled substances.  In addition, the  Parties added  methyl
bromide to the list of controlled substances and  agreed to  freeze production
of methyl bromide at 1991 levels  by January  1,  1995.   The reduction schedules
     •1  .Consumption is equal to production plus imports minus exports.

                    * 1994 UNEP SOLVENTS, COATINGS,' AND ADHESIVES REPORT *

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                 Table.I-1.  PARTIES TO THE MONTREAL  PROTOCOL
Algeria
Antigua and Barbuda
Argentina
Australia
Austria
Bahamas
Bahrain
Bangladesh
Barbados
Belarus
Belgium
Benin
Bosnia/Herzegovina
Botswana
Brazil
Brunei Darussalam
Bulgaria
Burkina Faso
Cameroon
Canada
Central African
  Republic
Chile
China
Colombia
Congo
Costa Rica
Cote d'Ivoire
Croatia
Cuba
Cyprus
Czech Republic
Denmark
Dominica
Ecuador
Egypt
El Salvador
EEC
Fiji
Finland
France
Gambia
Germany
Ghana
Greece
Grenada

Date:  February 1994
Guatemala
Guinea
Guyana
Honduras
Hungary
Iceland
India
Indonesia
Iran
Ireland
Israel
Italy
Jamaica
Japan
Jordan
Kenya
Kiribati-
Kuwait
Lebanon
Libyan Arab
  Jamahiriya
Liechtenstein
Luxembourg
Malawi
Malaysia
Maldives
Malta
Marshall Islands
Mauritius
Mexico
Monaco
Morocco
Myanmar        '
Namibia
Netherlands
New Zealand
Nicaragua
Niger
Nigeria
Norway
Pakistan
Panama
Papua New Guinea
Paraguay
Peru
 Philippines
 Poland
 Portugal
 Romania
 Republic of Korea
 Russian Federation
 St.  Kitts and Nevis
 St.  Lucia -
 Samoa
 Saudi Arabia
 Senegal
 Seychelles
 Singapore
 Slovakia
 Slovenia
 Solomon Islands
 South Africa
 Spain
 Sri Lanka
 Sudan
 Swaziland
 Sweden    -
 Switzerland
 Syrian Arab Republic
 Tanzania
 Thailand
 Togo
 Trinidad & Tobago
 Tunisia
 Turkey
• Turkmenistan
 Tuvalu
 Uganda
 Ukraine
 United Arab
   Emirates
 United Kingdom
 United 'States
 Uruguay
 Uzbekistan
 Venezuela
 Viet Nam  •
 Yugoslavia
 Zambia
 Zimbabwe
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT.
                                      1-2

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           Table 1-2.   SUBSTANCES CONTROLLED BY THE MONTREAL PROTOCOL
                                                             ODP Relative
                                                              to CFC-11
 Group  I:
 CFC-11
 CFC-12
 CFC-113
 CFC-114
 CFC-115

 Group  II:
 Halon-1211
 Halon-1301
 Halon-2402
                 ANNEXE A

Trichlorofluoromethane
Dichlorodifluoromethane
1,1,2-Trichloro-1,2,2-trifluoroethane
1,2-Dichlorotetrafluoroethane
Chloropentafluoroethane.
Bromochlorodifluoromethane
Bromotrifluoromethane
Dibromotetrafluoroethane
 0.8
 1.0
 0.6
 3.0
10.0
 6.0
 Group  I:
 CFC-13
 CFC-111
 CFC-112
.CFC-211
 CFC-212
•CFC-213
 CFC-214
 CFC-215
 CFC-216
 CFC-217

 Group  II:
 CC14

 Group  III:
 1,1,1-Trichloro-
 ethane
                 ANNEXE B

Chlorotrifluoromethane                         1.0
Pentachlorofluoroethane                        1.0
Tetrachlorodifluoroethane                      1.0
Heptachlorofluoropropane    .    .               1.0
Hexachlorodifluoropropane          .            1.0
Pentachlorotrifluoropropane                    1.0
Tetrachlorotetfafluoropropane        '          1.0
Trichloropentafluoropropane                    1.0
Dichlorohexafluoropropane                '      1.0
Chloroheptafluoropropane                 ,      1.0
Carbon Tetrachloride (tetrachlofomethane)      -1.1
Methyl Chloroform (1,1,1-Trichloroethane)      0.1
                                    ANNEXE C

Partially  halogenated fluorocarbons (including HCFC-22, HCFC-123, HCFC-141,
and HCFC-225),  are defined as transitional substances by the Montreal Protocol
under Annexe  C.

                                    ANNEXE E
Group  I:
CH3Br
Methyl Bromide
 0..7
 Source:   Montreal Protocol on Substances that Deplete the Ozone Layer
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                       1-3

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 set  out  in the Montreal Protocol Copenhagen Amendments of 1992 are shown in
 Table  1-3.

       Table 1-4  compares worldwide  consumption and ozone-depletion potentials
 .of CFG-11,  CFG-12,  CFG-113,  CFG-114,  and CFG-115.   Worldwide consumption of
 1,1,1-trichloroethane  in 1988  and 1990 was  679,000 MT,' and 726,000 MT,
 respectively (Midgeley  1991).  The  1988 consumption of 1,1,1-trichloroethane
 in the U.S,  Western Europe,  and  Japan was estimated at 582,000 MT (Chem
 Systems  1989).   It  has  been  estimated that  of this amount,  approximately
 100,000  MT of 1,1,1-trichloroethane were used outside W.  Europe,  Japan,  and
 the  U.S.  (Chem Systems  1989).  Figure 1-1 presents.the breakdown of 1,1,1,-
 trichloroethane  consumption  in these  three  regions.


 1.2  TERMS OF REFERENCE FOR  THE  COMMITTEE2

     The June 1990  London Meeting of  Parties to  the  Montreal Protocol
 reconvened the 1989 UNEP assessment'panels.   The 1989 UNEP  assessment panels
 consisted of the scientific  assessment,  the  environmental effects assessment,
 the  technology assessment, and the  economics assessment panels.   The technical
 and  economics panels were combined  for the  1991  Assessment.   The  three
 international assessment panels  were  requested to  report on:

     •    the science of stratospheric ozone-depletion
                           v
     •    the environmental  and  public health effects of stratospheric  ozone -
           depletion

    . •    the technical feasibility, and earliest possible date, -in each  of the
           major  use sectors, for phasing out production of  ozone-depleting
           substances and the related  anticipated economic concerns.  The 1991
           Technical and Economic Assessment  Panel  is divided into six
           Committees:                                 .    •  .

       •  '  --   UNEP Aerosols,  Sterilants, Miscellaneous Uses  and  Carbon
               Tetrachloride Technical Options Committee
               UNEP Economic Options  Committee
               UNEP Halons Technical  Options Committee
               UNEP Refrigeration Options Committee
               UNEP Solvents,  Coatings and Adhesives Technical Options
               Committee.
               UNEP Technical  Options Committee  for  Foams

     The  third meeting  of the  Parties to the Protocol in Nairobi  in June 1991
requested  the assessment  panels,  particularly the  Technology  Assessment  Panels
to:
     2 This section addresses Decision 11-13 Assessment Panels of the Second
Meeting of the Parties to the Montreal Protocol, Decision  111-12 Assessment
Panels and Decision III-8 Trade Names of Controlled  Substances of the Third
Meeting of the Parties to the Protocol (Kurita  1991b), and Decisions IV-13 and
IV-23 of the Fourth Meeting of the Parties  to the  Protocol.

                    * 1994 UNEP SOLVENTS, COATINGS. AND ADHESIVES REPORT  *
                                      1-4

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Table 1-3:  SUMMARY OF COPENHAGEN AMENDMENTS TO THE MONTREAL  PROTOCOL
Chlorofluorocarbons (Group I -  Annexe A: CFC-11,  CFC-12, CPC-113, CFC-
114,  CFC-115)              :              '

•     Freeze  at  1986 levels by July 1989
•     75  percent reduction from  1986 levels by January 1994
•     100 percent reduction from 1986 levels by January 1996

Other fully  halogenated CFCs (Group I - Annexe B: CFC-13,  CFC-lli, CFC-
112,  CFC-211, CFC-212,  CFC-213,  CFC-214, CFC-215, CFC-216, CFC-217)

•     20  percent .reduction from  1989 levels by January 1993
•     75  percent reduction from  1989 levels by January 1994
•     100 percent reduction from 1989 levels by January 1996

Halons (Group II -  Annexe A: Halon-1211, Ha Ion 1301,. Halon-2402)

•     Freeze  at  1986 levels by January 1992
•     100 percent reduction from 1986 levels by January 1994

1,1,1-Trichloroethane  (Group III - Annexe B)

•     Freeze  at  1989 levels by January 1993'
.•     50  percent reduction from  1989 levels by January 1994
•     100 percent reduction from 1989 levels by January 1996

Carbon Tetrachloride (Group II  - Annexe B)

•     85  percent reduction from  1989 levels by January 1995
•     100 percent reduction from 1989 levels by January 1996

Partially Halogenated  Fluorocarbons (Group I - Annexe C)

•     Freeze  at  specified level  by January 1996 (specified  level is equal
      to  3.1% of 1989 consumption of Group I Annexe A controlled
      substances plus 100% of 1989 consumption of  Group I Annexe C
      controlled substances)
      35  percent reduction from  level of freeze by January  2004
      65  percent reduction from  level of freeze by January  2010
      90  percent reduction from  level of freeze by January  2015
      99.5 percent reduction from level of freeze  by January 2020
      100 percent reduction from level of freeze by January 2030

Methyl Bromide  (Group  I - Annexe E)

•     Freeze  at  1991 levels by January 1995
               * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                 1-5

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     Table  1-4.   COMPARISON  OF WORLDWIDE CONSUMPTION OF CONTROLLED  CFCS
                      AND OZONE-DEPLETING  POTENTIAL (OOP)
1986 Worldwide
Consumption Percent of Relative Percent ODP
(kilotonnes) , Basket Total ODP of Basket
CFC-11 370 35.0 1.00 36i4 '
CFC-12 480 . ' . 45.4 1.00 47.2 '
CFC-113 178 16.8 0.80 14.0
CFC-114 15 1.4 1.00 • 1.5
CFC-115 15 . 1.4 0.60 0.9
Atmospheric
Lifetime
(years)
75
• 111
90
-
-
Source:  Montreal Protocol on  Substances that Deplete the Ozone Layer
                   * 199* UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      1-6

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                                             Figure 1-1

         BREAKDOWN OF 1,1,1-TRICHLOROETHANE CONSUMPTION IN THE U.S.,
                               WESTERN EUROPE, AND JAPAN
  Metal Cleaning
     55%
Adhesives
  9%
                Metal Cleaning
                   75%
                            Other
                            12%
       Aerosols
         9%
Electronics
   8%
         Coating
          7%
              USA
         280,000 metric tons
             Metal Cleaning
                 76%
           Other
           6%

         Electronics
         5%
       Aerosols
       4%
Adhesives
10%
                       Western Europe
                       15.1,000 metric tons
Adhesives
   5%

  Japan
                                                                                         Other
                                                                                         5%
              Electronics
              13%
Aerosols
  1%
                    151,000 metric tons
  Source; Chem Systems 1989
                       * 1994 UNEP SOLVENTS. COATINGS. AND ADHESIVES REPORT

                                    1-7

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      •     "evaluate, without prejudice  to Article  5  of  the Montreal
            Protocol, the implications, in particular  for developing
            countries, of the possibilities and  difficulties of  an earlier
            phase-out of the controlled substances,  for example  of the
            implications of a 1997 phase-out."

      •     "take into account the London Resolution on transitional
            Substances (Annexe VII ''to the report of  the Second Meeting  of the
            Parties to the Montreal Protocol), to  identify the specific areas
            where transitional substances are required to facilitate the
            earliest possible phase-out of controlled  substances,  taking into
            account environmental, technological,  and  economic factors,  where
            no other more environmentally suitable alternatives  are  available.
            The quantities likely to be needed for those  areas and for  those
            areas of application currently served by transitional  substances
            shall both be assessed."

      •     "request the assessment panels to identify the transitional
            substances with the lowest potential for ozone-depletion required
            for those areas and suggest,  if possible,  a technically  and
            economically feasible timetable,  indicating associated costs, for
            the elimination of transitional substances."

      •     "	submit... reports in time for their consideration by the
            Open-Ended Working Group with a view to  their submission for
            consideration by the Fourth Meeting  of the Parties."

      Most recently, the fourth meeting of the Parties to the Protocol,  held
in Copenhagen in November 1992, requested the following activities of the
assessment panels:

      •     "request the Technology and Economic Assessment Panel  and its
            Technical and Economic Options Committees  to'  report  annually to
            the Open-Ended Working Group  of the  Parties to Montreal  Protocol
            the technical progress in reducing the use and emissions of
            controlled .substances and assess  the use of alternatives,
            particularly their direct and indirect global-warming  effects'."

      •.     "request the three assessment panels to  update their reports and
            submit them to the Secretariat by 30 November 1994 .  .  .  These
            assessments should cover all  major facets  discussed  in the  1991
            assessments with enhanced emphasis on methyl  bromide.  The
            scientific assessment should  also include  an  evaluation  of  the
            impact of sub-sonic aircraft  on ozone."

      •     "encourage the panels to meet once a year  ..."

      To assure the widest possible international participation  in the  review
and the subsequent report, the 1994 Assessment Panels  consist of some members
of the 1989 and 1991 UNEP Assessment Panels and  additional new experts
nominated by Governments.  Not only were  experts from  industry,  government,
academic institutions, and nongovernmental organizations  invited to  prepare a
comprehensive and technically specific "Control  Options Report"  for  each
sector,  but the chairpersons of the.UNEP  Technical and Economics Panel  and
each of the Technical and Economics Option Committee also contacted  countries

                    * 199H UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      1-8

-------
to encourage their active participation  in  this  review process.   By contacting
producers, manufacturers, and  trade  associations and by  arranging for
additional technical  input,  the chairpersons of  the Technical  and Economic
Option Committee  further insured widespread participation  in preparing  the
Technical Options Report on  Solvents, Coatings,  and Adhesives.  As with the
1989 and 1991 reports,  the 1994 report has  undergone extensive peer review and
will be distributed internationally  by UNEP.

      The member  countries of  the  Committee included representatives from
North American, Latin American, European, African, and Asian governments and
companies (see Table  1-5).   Affiliations  of the  committee  members are listed
in Table 1-6.  In addition,  the Committee had  the benefit  of advice from a
distinguished panel of  worldwide experts  which included  representatives of
government agencies,  chemical  producers,  and industry associations (see Table
I--7) .  Committee meetings during the preparation of the  1991 report were held
in Germany, Japan, Mexico, Sweden, Switzerland,  Thailand,  United  Kingdom,, and
the United States to  facilitate participation  by interested organizations.
These meetings enabled  Committee members  to gather information first hand on
the potential for substitution of  CFC-113 and  1,1,1-trichloroethane and on the
progress made to date.  The  Committee met with a number  of companies, trade
associations, and government agencies to  understand their  position on this
issue.
1.3   BASIS FOR COMMITTEE RECOMMENDATIONS TO UNEP AND COMMITTEE POSITION ON
      CFC-113. 1.1.1-TRICHLOROETHANE AND PARTIALLY HALOGENATED FLUOROCARBONS

      The Committee's recommendations to the UNEP are the consensus of  the
Committee.  New scientific information suggests that ozone depletion  is
occurring at a rapid rate!  The levels of future chlorine and bromine
concentrations in the upper atmosphere will depend primarily on future
emissions of CFCs, 1,1,1-trichloroethane, halons, HCFCs, halothanes.  and other
ozone-depleting substances.           '

      In August 1988, the U.S. Environmental Protection Agency (EPA)  issued a
study entitled "Future Concentrations of Stratospheric Chlorine arid Bromine"3
which looked at chlorine and bromine levels after the implementation  of the
restrictions in the Montreal Protocol.  The U.S. EPA predicted that,  based on
their growth scenarios, levels of chlorine' in the stratosphere would  increase
from 2.7 to 8 parts per billion '(ppb) by 2075, even with the reductions in CFC
production called for in the Protocol. 'This increase would be caused not only'
by the allowed use of CFCs and. halons under the P.rotocol, but also by CFC use
in countries that are not members of the Protocol and by the growth in  the
production and use of chemicals such as 1,1,1-trichloroethane and carbon .
tetrachloride.  While reduction efforts under the Protocol, coupled-with the
greatly increased number of signatories, is likely to result in increases in
stratospheric chlorine levels  closer to the low end of this range, such
increases are still of concern.  '

      The second and third meetings of Parties to the Protocol in London and
Nairobi called for an examination by the Committee of the technical
     3 Clx Report, U.S. EPA. Office of Air and Radiation, 400/1-88/005, August'
1988.          '                                       '   •   (       .

                    >•• '1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      1-9

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          Table  1-5.   MEMBER COUNTRIES OF THE UNEP
SOLVENTS, COATINGS AND ADHESIVES TECHNICAL OPTIONS  COMMITTEE
                       Member Countries
                       Belgium
                       Brazil
                       Canada
                       France
                       Germany
                       Japan
                       Jordan
                       Germany
                       Malaysia
                       Mexico
                       Singapore
                       Sweden
                       Switzerland
                       Thailand
                       United Kingdom
                       United States
          * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

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      Table 1-6.  ORGANIZATIONS WHOSE  EMPLOYEES  SERVE  ON THE
UNEP SOLVENTS, COATINGS, AND ADHESIVES TECHNICAL OPTIONS COMMITTEE
                       Member Organizations
         Allied Signal Incorporated
         Asahi Glass Company Ltd.
         AT&T Bell Laboratories
         Boeing Company
         British Aerospace (Dynamics) Ltd.
         Charles Stark Draper Laboratory
         Digital Equipment Corporation
         Dow Chemical - Advanced Gleaning Systems
         European Chlorinated.Solvents Association
         Ford Motor Company                          •
         Friends of the Earth
         GEC -'Marconi
         Global Centre for Process Change
         Hitachi Ltd!
         ICF Incorporated
         IFC                               .    .
         ITT Teves GmbH
         Japan Association for Hygiene of Chlorinated Solvents
         Japan Audit and Certification Organisation Ltd.
         JEMA
         Lockheed
         Lufthansa German Airlines
         Mexican Chamber of Industries
         Ministry of Planning - Jordan
         National Semiconductor
         OXITENO
         Promosol         •           • •        .
         Protonique S.A.
         SAEO South America Electronics Operation
         Siemens AG
         Singapore Institute of Standards and Industrial Research
         Sketchley PLG
         Swedish Environmental Protection Agency
         TELEMECANIQUE
         Texas Instruments Incorporated
         Thai Airways International
         U.S. Air Force
         U.S. Environmental Protection .Agency
         Vulcan Chemicals
         Waste Policy Institute
             * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                               1-11

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  Table 1-7.  CORPORATE AND GOVERNMENT PRESENTATIONS  IN  MEETINGS  HELD BY THE
      UNEP SOLVENTS, COATINGS, AND ADHESIVES TECHNICAL OPTIONS  COMMITTEE


1Allied Signal,Inc.,  U.S.A.
2A11 Japan Laundry and Dry Cleaning Association, Japan
2Alpha Metals, Hong Kong
2Arakawa Chemical Industries, Ltd., Japan
3Asahi Glass Company, Ltd., Japan
2Asea Brown Boveri (ABB)
2Atsugi Unisia Corporation, Japan
2AT&T-Telecommunications Products (Thai) Ltd., Thailand
2Balzers A.G., Principality of Liechtenstein
2Berghof GmbH & Co.,  Germany
3Boeing Company, U.S.
3British Aerospace (Dynamics) Ltd., U.K.
3Brulin Corporation
2Canon, Inc., Japan
2Chemical Technology Research Co., Ltd., Japan
2Columbia Cement, Co.,  Inc.
2ConSolve, A.S., Norway
3Daikin Industries, Japan
2Dan Science Co'. , Ltd. ,  Japan
2Data General, Thailand"
3Deft Corporation
Department of Industrial Works - Ministry of Industry, Thailand
2Digital Equipment Corporation, Singapore
2Dow Chemical, Germany,  Switzerland
2Du Pont Electronics, U.K.
3Du Pont,  Japan, U.K.,  and U.S.A.
2Durr GmbH,'Germany
1Ensambles Magneticos,  S.A., Mexico
2Ericsson Electronics,  Sweden
3Exxon Chemicals, Canada
2Fujitsu Ltd., Japan
2FFV Aerotech, Sweden
2GEC Research, U.K.
2General Dynamics, U.S.A.
1Halogenated Solvents Industry Alliance, U.S.A.
2Hitachi Chemical Techno-Plant Co., Ltd., Japan
2Hitachi,  Ltd.,  Japan
2Hitachi Construction Machinery Co.,  Ltd., Japan
2IBM,  Sweden
3ICI PLC Chemicals and Polymers Ltd., U.K.
International Institute for Energy Conservation, Asia Office, Thailand
2ITT Teves Gmbh, Germany
2Japan Alcohol Association, Japan
2Japan Electrical Manufacturers' Assn., Japan  .
2Karl Roll GmbH, Germany                                    •
2Koki Company, Ltd.,  Japan
2Kolb GmbH & Co., Germany
2Leica Heerbrugg, Switzerland
3LPS Laboratories, U.S.
2Matsushita Refrigeration Co.,  Japan
2Micropolis Corporation,  Thailand
2Minebea Group,  Thailand
1Ministry  of International Trade and Industry, Japan
Mitsubishi Electric  Corp., Japan

                            (continued on next page)


                   * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     1-12

-------
  Table 1-7.  CORPORATE AND GOVERNMENT PRESENTATIONS  IN MEETINGS  HELD  BY THE
      UNEP SOLVENTS, COATINGS, AND ADHESIVES TECHNICAL OPTIONS  COMMITTEE
                                  (Continued)


33M Corporation
2National Semiconductor, Thailand
2National Research Institute for Pollution and Resources, MITI,  Japan
^EC,  Japan
2Nippondenso Company, Ltd.,  Japan
2Nissan Motor Co., Ltd., Japan
2Nissin Electric,  Japan
1Northern Telecom, U.S.A.  and Canada
2NTN Corporation,  Japan          -           .               .'
1Plamex S.A.,  Mexico
2SAAB Scania,  Sweden
4SAGEM, France
^EHO, Germany                       .                      •
1 Seiko-Epson,  Japan
2Semiconductor Ventures International,  Thailand
2Senju Metal Industry Co., Ltd, Japan
Reparation Technologists, U.S.A.
1 Sharp Corporation, Japan
2Siam Compressor Industry Co.,  Ltd.,  Thailand
3Siemens,  Germany
2Siemens-Ele'ma,  Sweden                                     .
1Sigma Industries, U.S.A.
2Swedish Institute for Production Engineering Research, Sweden
2Tinker Air Force Base, U.S.A.
3Toshiba Corporation, Japan
2Toshiba Display Devices (Thailand)  Co.,  Ltd., Thailand
4Thiokol Corporation, U.S.A.                                       .         .
2ULVAC Ltd.,  Japan
1United States Air Force Engineering Services Center, Tyndall Air Force  Base,
   U.S.A.                                                                  •
2VCI,  Germany
2VOLVO Aero Support
3W.R.  Grace,  U.S.
2ZVEI, Germany


1  1989 Presentation.                         ,                  .
2  1991 Presentation.
3  1989 and 1991 Presentations.                                   .
4  1994 Presentations.
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                      1-13

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 feasibility  of using only  alternatives  which do not deplete the ozone layer.
 In the  short-term some  might use other  low OOP alternatives.   Figure 1-2
 compares  the ODP  of  CFC-113  and 1,1,1-trichloroethane with that of the new
 HCFCs and HFCs currently In  use or under development.  The Committee believes
 that there are a  wide variety of alternatives that can completely replace CFC-
 113 and 1,1,1-trichloroethane use.

      A variety of alternative substances and technologies are currently under
 development  to facilitate  the phaseout  of CFC-113  and 1,1,1-trichloroethane.
 These alternatives include aqueous and  semi-aqueous cleaning,  alcohol
 mixtures, other hydrocarbon  solvents, HCFCs,  perfluorocarbons,  no-clean
 technologies,  and a  growing  number of non-solvent  cleaning processes.

      No-clean technologies  represent the optimum  alternative  and have been
 applied in an increasingly large number of electronics manufacturing
 applications in recent  years.   Nevertheless,  research and testing of no-clean
 manufacturing processes is ongoing in hopes of making it a viable alternative
 in a wider variety of uses.   Second to  no-clean with respect  to ozone layer
 protection is aqueous or semi-aqueous cleaning.  The major drawbacks of these
 alternatives may  be  high energy consumption and wastewater treatment costs.

      HCFCs,  though  their  use is transitional,  are important  alternatives to
 CFC-113 and  1,1,1-trichloroethane solvent use in applications  for which no
 other viable alternative exists.   Because of their lower ozone-depletion
 potential, HCFCs  with a short lifetime  (below 10 years)  are preferred to those
 with longer  lifetimes (over  15 years).   However, HCFCs should  only be used as
 substitutes  for 1,1,1-trichloroethane if their ODP is lower than 0.10 and if
 their emissions are  controlled using the best available  technology.   As a
 result  of the 1992 Copenhagen Amendments to the  Montreal Protocol,  HCFC use is
 only a  temporary  alternative.   The  amendments state that consumption of HCFCs
 must be reduced by 99.5% by  202.0 and completely  phased out by  2030.   In the
 interim, the  Protocol recommends that HCFCs only be used in conjunction with
 emission control  recovery  and recycling systems.   Thus,  HCFCs  are a valid
 alternative  in certain  limited applications while  other,  long-term
 alternatives  are  being  developed (Yamabe 1991).4
     4 Low ODP alternatives, coupled with recovery systems, could be effective
in protecting the ozone layer.  The recovery system would  be  effective  in
•reducing the consumption of ozone-depleting chemicals  in small  factories,
where more than 50 percent of the consumption of  these chemicals  takes  place
(Yamabe 1991).

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT  *
                                     1-14

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   0.
   a
   O
                                  Figure 1-2.

     RELATIVE TOTAL OZONE DEPLETING POTENTIAL OF

            SELECTED HALOGENATED SOLVENTS*
                                                             0.80
                               0.15
                       0.00  0.00
                                                0.10
                                   0.06
        0.00  0.00
                                                        0.04
                                                    0.01
                       125  134a
 T

141b  142b



 Solvents
143a  152a  1.1.1  225ca 225cb CFC-113
' Relative to CFC-11 which Is set at a value of 1.
                                                                       llf>077 1
            * 1994 UNEP SOLVENTS, COATINGS. AND ADHESIVES REPORT *


                         1-15

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                                   CHAPTER 2

                       ELECTRONICS INDUSTRY APPLICATIONS
2.1   BACKGROUND

      Since  the publication of the  1991  Solvents,  Coatings  and Adhesives
Technical Option  Committee  (TOC)  report,  considerable  practical,  commercial,
'and technical  developments  have occurred.   Several nations,  including Germany,
Sweden and Switzerland,  already have  legislation in force  to phaseout ozone -
depleting solvents.  Many other countries,  as  well as  individual  users, have
achieved spectacular reductions.  ,

      Unfortunately, some electronics  companies  in some  nations are  unpreparedi
for the 1 January 1996 phaseout.  This situation is difficult to  understand,
as the electronics  industry has found  reasonable solutions'for practically all
the problems that have arisen.

      This chapter  has been rewritten, not  merely updated,  in an  attempt  to
keep it a manageable size and  due to  the  significant progress that has
occurred in  the electronics industry.

    •  The principal use  of  CFC-113  and 1,1,1-trichloroethane (methyl
chloroform)  solvents in  the electronics  industry is for  defluxing, that is,
the removal  of residues  from assemblies  after  soldering..  The flux or solder
paste residues1 are characterised as a mixture of:

      •      raw flux                .               .
      •      thermally modified flux
      •      flux  decomposition products
      •      reaction products  between  the flux components and metal  oxides
             from  the printed circuit boards, the component  leads, and the
             molten  solder
      •      residues - modified or  otherwise - from contaminants  previously
             left  on the  boards and  components
      •    .  residues from soldering oils
      •      paste modifiers.

      A further use for  1,1,1-trichloroethane  is in printed circuit
fabrication  as a  developer  for photosensitive  coatings,  mainly dry film
photoresists and  dry film solder  masks.

      The dissemination  of  information to small  production  units  on
substitutes  for ozone-depleting solvents  is a  problem  in many nations.  This
may be due to  difficulty in assessing  substitutes and  because companies are
often too small or  too remotely located  to  use consultants  effectively.
1   In this chapter, the word flux may be considered as  including  solder  paste,
except where there  is a significant  distinction specified.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
              .    •                    2-1

-------
Language may also play a  significant  role.,  as  most  of the  information is
published in English.  This has been  discussed in the 1994 TEAP report (UNEP
1994).

      One other factor which has  retarded  the  phase,-.out  of CFC-113  in the
electronics industry has  been  specifications which  discouraged using
substitute cleaning processes  for military and similar applications.   Much
ordinary electronics production,  particularly  in  the  smaller  firms,  was
cleaned to military approved requirements  using CFC-113  arid 1,1,1-
trichloroethane, even though it'was not" strictly  necessary.   To avoid
duplication of processes  and equipment,  the military  standards were  used  for
non-military work, which  resulted in  unnecessarily  large CFC  emissions.   In
February 1991, the U.S. military  adopted MIL-STD-,2000 /  Revision A  (DoD,
1991).  This standard conditionally permits the use of non-rosin  fluxes and
non-ozone depleting solvents and  cleaning  processes for  most  electronics
assembly and retroactively for existing contracts.  MIL- STD.- 2000  (Rev A)  also
recommends that CFC solvents "be  phased out".   This revision  to -US  military.
standards has already had a far-reaching and global effect.   Nevertheless,
there is little room for  complacency,  as was shown  by the  report  to  a recent
conference concentrating  on these problems  (NATO  1994).

      In the electronics  industry, there are six  primary methods  that are
suitable for replacing ozone-depleting substances (ODSs) (Figure  II-l), each
with a number of important variants.   The  following list,  although .not
exhaustive, is a general  review of these as they  apply to  fluxes  and solder
pastes.

      •     "No-Clean" methods, including  controlled  atmosphere soldering
      •     Water soluble fluxes  and  water  cleaning
      •     Rosin fluxes  + saponifier + water  cleaning
      •     Rosin & SA fluxes  + hydrocarbon/surfactant + water cleaning
      •     Rosin & SA -fluxes  + hydrocarbon and derivative (Including alcohol)
            solvent cleaning             •         '  •
      •     Rosin & SA fluxes  + permitted  halocarbon  solvent  cleaning.

      Due to the numerous financial and environmental considerations,  the.
Solvents TOC recommends that the.  substitute process be fully  tested,
qualified,  and found satisfactory under full production  conditions before any
capital investment is made.  In addition,  the  process and  its  supporting
infrastructure should include  approval  by  all  the appropriate  fire,  health,
safety, and environmental authorities.

      The following list  of questions  can help.users  decide whether  or not to
clean:

      •     is human life, "at stake?*
      •     is the assembly working at  high frequency or high  impedance?*
      •     are analogue  signal levels  low?*
2  This standard details requirements for the materials and processes which
may be used in making soldered connections  in electronic  assemblies.  The
soldered connections which must meet this standard's  specifications  include:
lead and wires inserted in holes, surface-mounted  components,  and  components
attached to terminals.

                    * 1994 UNEP  SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                                      2-2

-------
Replacement of OD solvents in the military electronics industry
j     |  OK for all military applications



I       OK for some military applications  ~ with controls


•  • "  Specifically tested and
.  . .  approved to DEF-STAN 00-10/3
                Permitted halocarbon
                cleaning????
               ^^^ &^_M                _         I

           I Inert atmosphere  | (Reactive atmosphere •  -j
/     I Low-residue flux
Controlled atmosphere
soldering
t3
•S
Q>
a
             No-clean" processes
                                                                  ("jra3iB6nai wafer" '
                                                                   ;spluble flux.    •••''•
                            rbon-surfactant
                                                j; cleaning;* water^
             Prozone is a registered Trade Mark of British Petroleum Chemicals Limited.
            Figure  II-l.  Methods of  replacing ozone-depleting
            solvents in  the electronics industry.  .   • •
                      * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *.
                                           2-3

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      •     is reliability  important?*
      •     are assemblies  likely  to be  subject  to high .temperatures3, high
            humidity or rapidly  changing atmospheric  conditions?*
      •     are assemblies  to be conformally  coated?*
      •     does the customer specify high.reliability standards?*
      •     does the customer exact a long  guaranteed lifetime?*
      •     is cost subordinate  to other factors?
      •     Is the aspect of the circuit important?
      •     is automatic testing to be done?
      •     is burn-in of the finished assembly  done?

The questions with an asterisk  (*) are more important in  the  decision process.

      Where cleaning is necessary, there are  problems of  scale.   With CFC-113
vapour defluxing, the equipment  price is roughly proportional to the
throughput capacity; this,  however, is not  always the case  with  substitute
methods.  To achieve a change which produces  a satisfactory quality,  small
manufacturers in both developing and developed nations may  have  to pay
disproportionately more for the  equipment.  In many instances, these "capital
costs may be offset by lower operating costs.

      Finally, before assembly  is  done,  the design of the printed circuit is
an all-important factor which is frequently ignored.   Successful use  of  "No-
Clean" fluxes, particularly with wave-soldered SM components,  is dependent on
correct PCB design.  Similarly,  if cleaning is to be  carried  out,  the criteria
are very different and other design factors are  required.   Often a circuit
which gives excellent results with one process gives  very'poor results with
another.  Section (2.2) is  a new section which addresses  this problem.
2.2   PRINTED CIRCUIT DESIGN FOR  EFFICIENT  SOLDERING AND  CLEANING

      The use of certain soldering and cleaning processes can be optimised .
only if the PCB is designed correctly for that process  (Ellis 1994).   The, use
of anything other-than-optimised  may seriously compromise the. efficiency.of
the chosen process.  This section gives  the .designer an introduction  to  the
subject.  A designer must be informed as to which  soldering  and cleaning
processes are to be used in production before starting  work.  -It is assumed
that the designer uses a quality  electronics CAD system,  without it being .
specific to one type.  Users of manual draughting,  low-cost  CAD systems  or
those adapted from mechanical. CAD packages  may have to  make  some modifications
and make many manual retouches to comply with the  following  recommendations.

      2.2.1 Low-Solids "No-Clean" flux wave soldering

      the use of Low-Solids "No-Clean" fluxes presents  the biggest challenge
to the PCB designer, particularly for the SMD circuit.  The  PCB design is
critical to exploit the operating window, which can b'e  quite small.'

      Traditional High-Residue fluxes for SMD soldering present a severe
disadvantage when soldering SMD components with a  conventional wave soldering
machine.  The components themselves create  "shadows." which prevent, correct
3  Rosin fluxes start to soften at about 70°C.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      2-4

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 soldering  from taking place.   This was  circumvented by using "double-wave"
 soldering  machines:  the  first wave was  very turbulent to ensure the solder
 penetrated into the  "shadows",  but left uncontrolled amounts of solder on the
 joints  and between conductors.   The second wave was a smooth,  streamline wave
 whose function was to remove  the excess- solder and to leave sufficient to form
 a perfect  meniscus at each joint.         .   -

      Without  extensive  engineering it  is  generally not possible to use'the
 "double-wave"  technique  with  Low-Solids "No-Clean"  fluxes because the
 turbulent  wave offers sufficient agitation so  that  the quasi-totality  of the
 flux activator is  removed.  The second  wave has to  operate practically without
 activator  present  and the  solder joint  which results is usually defective. "A
 few Low-Solids "No-Clean"  fluxes are  designed  to permit double-wave soldering
 but these  may  present other disadvantages.   It is therefore necessary  to
 ensure, by careful layout,  minimum shadowing by the components,  so  that a
 single  wave may be used.

      Design for Low-Solids "No-Clean"  flux soldering of SMD circuits  implies
 that no solder joint  be  placed  on  the last side of  the component to '"see" the
 solder  wave.   With components  that have connections along .two  sides, such as
 passive 'Chip components  and SMSO ICs, these should  present themselves  so  that
 all the solder lands  be  on  either  side  of  the  device as "seen"  by the  wave.   A
 problem obviously  presents  itself  with  components which have soldering lands
 along all  four sides,  such  as gull-wing, J-lead PLCCs,  or LCCCs.   Shadowing
 may be minimised by placing this type of device at  45  degrees  to the wave
 angle.  This generally works with  the better fluxes.   Some of  the less
versatile  CAD  systems  do not permit turning components through  45 de,grees or,
 if they do, they may  not allow  the connecting  tracks to come out in a  very
 logical way.   This would imply  that the component actually be  designed
 specifically in the library at  the required angle,  thereby using up four
 custom pad  (land)  sizes, instead of .one.   The  best  method uses  a rectangular
pad design with the actual  connection offset to the outer edge,  if  the design
 rules' do not allow the connection  to be forced at the  designed  angle.   Some
manual retouching  may  be needed after autorouting.  .As cleaning  will,not  be
carried out, the pad width  may  be  as wide  as is necessary to ensure that
bridging does  not  occur and that the minimum gap width be respected.   Via
holes should be  spaced away from the pad by an intermediate  connection between
them and the hole  of  a minimum  of  1 mm,  even if they are  tented,  filled or
otherwise rendered unsolderable.   The major axis of the interconnecting tracks
should be parallel to  the axis  of  the soldering machine, .even  if they  are
covered with a  solder  resis-t or mask, in order to ensure  minimum solder
                                         t
balling.  For  double-sided  boards  with  wave-soldered SM components  on  both
sides,  this implies that the boards be  soldered in  different directions for
eacti side,  as most CAD systems  force the major routing at 90 degrees;  in  any
case,  this uses  the "real'estate"  most  efficiently.  With multilayer circuits,
the problem is  not the same as  both the outer  layers may  be  forced  in  the same
direction,  according  to the flexibility of .the design  rules  of  the  system.

      Figure II-2  illustrates an example of a  hypothetical design for  Low-
Solids "No-Clean"  soldering.           .

      2.2.2 Controlled Atmosphere  Soldering

     . This presents exactly similar problems to that of .the  Low-Solids "No-
Clean" flux case and  the same criteria  apply,  as in the preceding section.


                   *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      2-5

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  Direction of passage over solder wave
   •  •   I   I •  •   I   I •  •   I   I  •  •   I
  llllill   MIMIM  I   IIIMIM I   I MM »M I


  if. FV?  ... •[• Tf1   • LL« i  T:  •  ii. r :₯
 -iTiTTiT I   rrnTrn     rrlrnn    mrniT
  •   •ii    *  • i  i   •   •ii    *  *  i i


  iliiiii I   liiiiiii  I   Imiiii I   ILUJJII I

 TT^lF!  ' i   i  I;*1   'I'T'iip  ":"j JJF

  11. riy  -if. T-y-.."iL_T-₯  .11. i  ₯
  iliiiii    ntmTi     iTrrmi    nriirrr
  •   •  ii    •  •ii   «   » i i    •  •  i i
Figure II-2. Hypothetical  example of SMD circuit


designed for "No-Clean"  wave  soldering showing correct


orientation of components.
         1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

                         2-6

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       2.2.3 "Traditional" flux soldering and cleaning

       "Traditional" fluxes may be considered as activated rosin (RMA, RA or F-
 SW32 halide free) or water soluble types.  The design criteria for soldering
 with these fluxes are far less critical and therefore the accent is best
 placed on cleaning.  For through-hole circuitry, no change is required to the
 design rules.   The problems arise when cleaning SMDs.

       In reality, cleaning with CFC-113 is, in most cases, just as difficult
 as with any of the substitute processes, if not more so.  This section
 therefore applies to all cleaning methods.

       The cleaning solvent, be it aqueous or organic,  must penetrate as freely
 as possible under the components and, having penetrated, must circulate.
 Young's law indicates that pure water, with a high surface tension, will
 penetrate better, by capillary action, into close spaces than would an organic
 solvent or a less pure water, with a lower surface tension.  If free
 circulation is to take place, then the spaces must be as wide as possible and
 the obstructions be minimised.  It is therefore important to choose those
 components which have the largest stand-off from the printed circuit board.
 With plastic moulded components, .it is quite usual to place small stand-off
 "blips" in the corners..  Ideally, these "blips" should also have the smallest
 surface area,  although this criterion is secondary to the height.   Smaller
 components, such .as 1206 passive chips, have relatively little difficulty, as
 far as cleaning is concerned, because of the small area to stand-off ratio.

       The placement of wave-soldered SM circuits is therefore the most
 critical factor and should, as ideally as possible, be done as a function of
 the component height.  Some .CAD systems will permit autoplacement where
 component height can be a function by limiting tall components to specific ,
 parts of the boards, while retaining coupled components (e.g. decoupling
 capacitors).  The space round tall components should also be greater than
 round low ones.  This can be done by using a larger rectangular silk profile
 than that of the component itself and replacing it after the layout is
 completed by an autolibrary function, if there is no .other way possible to
 ensure the best conditions within the framework of the CAD system.   When
 considering component spacing, it must be assumed that worst-case positional
 tolerancing will occur: it is therefore a mistake to' force components too
 closely together: in fact, the ideal situation is to use the "real estate" of
 the PCB to best advantage to maximise component spacing.  Orientation is also
 critical.   This should be arranged to allow the .maximum ingress of cleaning
 fluid,  so the design is also a function of the way the finished circuit will
 pass through the cleaning machine and of the way that the machine operates.
 In-line conveyorised spray machines with the jets normal to the surface of the
 board are generally less efficient than batch machines where the jets may
 attack the boards at an angle as small as 15 degrees.   On the other hand, the
 former are perhaps much less prone to shadowing problems as the liquid can
 penetrate the inter-component space more readily, even if it tends to "puddle"
 and stagnate there, rather than circulate.

       Figures II-3 and II-4 show a few ideas as to the best,principled to
 adopt when designing the placement of boards to be cleaned.  Pad width becomes
 very critical,  in this case, as having a broad solder meniscus' on four-sided
 connection components will reduce the ingress of cleaning fluids by as much as
'50 percent, especially if the solvent loses kinetic energy by striking the


                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       2-7

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            Layout criteria for effective cleaning
                                Orientation of SOICs and chips: left OK, right poor
               § Taking into account
               jl positional tolerances
                ! and the component
               3 height, make sure
                 there is adequate space
                ' between them to allow
                i
                | cleaning fluid to circulate

Fig-2
                                                          Do not put large
                                                          components in the
                                                          line of spray to smaller
                                                          ones
            Figure 11-3. Layout  criteria for effective  cleaning
            a) orientation and position -
                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                        2-8

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           Layout criteria for effective cleaning
Components placed at an
angle: Solder joints brake the
energetic ingress of cleaning
products.
Minimal sized soldering
lands: maximum ingress
of cleaning products.
Solder lands too wide:
ingress of cleaning
products reduced
by 50%.
Fie.3
            •Figure II-4.  Layout Criteria for Effective  Cleaning
             b) Maximum ingress, of cleaning fluids
                   * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      2-9

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 board surface before being deviated under the components.  It is therefore
 important,  in all cases,  to use a pad width which is as narrow as possible,
.but consistent with good soldering quality.  Such components must never be
 placed at 45 degrees to the axis of the cleaning machine, as the angle will
 reduce the "window" between solder joints by 30%: the component must always be
 axial.

       2.2.4 "Glue-spots"  and cleaning quality

       The position of the Glue-spots on boards which are not cleaned is not
 very critical,  within normal parameters.   On the other hand, they may be
 critical for boards which must be cleaned,  as they can restrict the flow of
 cleaning fluids.   With small components,  the Glue-spot is generally placed
 centrally.   With  heavier  components, two or more Glue-spots may be required.
 If two are used,  then the ideal configuration is they should form an axis
 which is not in line with the"cleaning machine (as well as being of minimum
 size).  Either 45 or 90 degrees is generally satisfactory.  With three or more
 spots, care should' be taken to-avoid shadowing of the space between them.
 Most good CAD systems can automatically incorporate the Glue-spot positions in
 the component libraries,  according to the operator's wishes.

       2.2.5 "No-Clean" Paste Reflow soldering

       Most "No-Clean" pastes have considerably higher residue levels than many
 other "No-Clean"  soldering processes as the chemistry must contain sufficient
 product to ensure the correct viscosity and .rheological characteristics.   As
 the paste is reflowed homogeneously by infra-red radiation or by vapour phase
 PFC heating,  there are few 'orientational problems.   As such, there are few
 critical design parameters other than those imposed by the'soldering process
 itself.   Soldering land width and spacing may be critical and the CAD design
 rules may need some fine  tuning.   During component placement,  the distance
 between components must be sufficient to permit the heating medium to pass.
 One of the  main difficulties which is sometimes encountered is that of solder
 balls.   These may cause electrical and/or mechanical problems but they are not
 so  much a design  problem  as one of the soldering conditions  themselves and the
 paste quality and age.  Even more important than with wave soldering,  via
 holes must  be well separated from the soldering pads or lands,  otherwise the
 molten solder may be drained from where i,t is necessary.
                                                          f
       2.2.6 "Traditional"  Paste Reflow Soldering and cleaning

       The design  rules for rosin or water-soluble paste are  similar to those
 for "No-Clean"  pastes.  The components should be selected with maximum stand-
 off heights and with other characteristics suitable for re.flow and wave
 soldering.
 2.3   CFC-113 USE  IN  ELECTRONICS  ASSEMBLIES

      2.3.1 Mai or.Assembly  Processes

      Electronic compo'nents are fluxed and soldered to electronic assemblies
 and then  cleaned to remove  flux residue and  other contaminants introduced in
 the production•process.   The electronic components are attached by either
 through-hole assembly technology  or by surface-mounted assembly technology or


                    *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      2-10

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a combination  of  the  two.   The  actual  techniques  are only secondary to the
problems  of  cleaning,  so  they will  not be discussed here.   For further
details,  please consult  the 1989  and 1991 Solvents  TOC reports (UNEP 1989,
1991) or  other literature  (Ellis  1986).

      Boards are  soldered  in one.of two general ways:  (1)  a molten Bolder is
used to solder and  secure  the components onto  the board or (2) a solid solder
(normally in the  form of wire solder or small  solder spheres in a flux paste
matrix) is deposited  on  the board and  later heated.   Wave,  dip,  and drag
soldering are  examples of  the former;  manual,  infra-red,  condensation reflow,
or hot gas soldering  are examples of the latter.  Wave soldering is commonly
used in high-throughput  electronic  assembly operations.   Wave-soldered boards
are fluxed and passed over a wave of solder that  flows up  from the solder
bath.  The solder forms  an intermetallic bond  with  the surfaces  of the
component leads and tracks and  with the  plated through-holes of the printed
wiring boards.                                          .

      Flux is  removed from electronics  assemblies to:

      •     remove  corrosive flux ingredients
      •     improve adhesion of conformal -coatings
      •     enable  easier  visual  inspection
      •     facilitate automatic  testing
      •     minimise  leakage currents  •       "•
      •     enhance product appearance        . .
      •     to. conform to  customer  specifications

      The need for  post-solder  flux-residue cleaning varies  widely and depends
on the final electronics application.   For  example,.most printed circuit
boards that are. used  in toys and  home  appliances  are cleaned perfunctorily, if
at all.   In contrast, boards that are  manufactured  for automotive,  military,
space,  medical and  other critical applications require high  levels of
cleanliness.   Frequently,  boards  require cleaning for  automatic  testing rather
than for  reliability  (IPC  1986).  However,  in  applications where assemblies
are exposed to elevated temperature and  humidity, flux residues  can corrode
metallic  tracks on-, electronics  assemblies and  component leads  and also create
deleterious effects on the  electrical  characteristics  of  the insulation (see
Section 2..1) .                                  ''       ,   .

    .  2.3.2 Flux  Types

      "No-Clean", rosin/resin,  synthetically activated, and  water-soluble
(also frequently  referred  to as organic  acid)  are the  major  flux types.

      There are several variations  in  so-called "No-Clean"  flux  types,
containing quantities of resins (some  with  wood rosin)  ranging from zero•up to
about 5% w/w.  They all have high degrees of activation, compared to  more
traditional rosin or  resin fluxes.   In extreme cases,  the  solid  matter may be
entirely  activators.  The  activators are most  frequently based on non-
halogenated linear  carboxylic acids, although  some  types also  use cyclic acids
or organic hydrohalide compounds  either  alone  or  in combination.   They are
also referred  to  as "Low-Solids"  fluxes.  The  terminology,  in either  .case, is
not necessarily precise as,some fluxes  with a  low solids  content may  possibly
lend -themselves to  cleaning and some fluxes .with  a  higher  solids content may
be perfectly adapted  to not being cleaned (DIN-Normen).  As  a general rule,


                    *  1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
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 the operating  "window" when  soldering with  "No-Clean"  fluxes  is  narrower  than
 with many other flux  types and  they  are  often more  prone  to  cause  solder-
 balling  (solder balls are.small metallic spheroid particles  of typical
 diameters within  the  range of 0..05 to 0.5 mm  and  which tend  to adhere  to  the
 printed  circuit substrate.)

      When properly prepared, traditional rosin fluxes meet  U.S. military
 specifications  (MIL-F-14256),*  have  a history of  successful use, and do not
 always need to be  removed after soldering.  Rosin is a complex mixture  of
 isomeric acids and rosin fluxes are  classified by the  amount  of  activator
 present.  Activators, generally halides  or  carboxylic  acids  or a combination
 of both, increase  the wetting ability of the  solder by reducing  oxides  present
 on the surfaces to be soldered.  While they are the least corrosive  and
 conductive fluxes, rosin fluxes have limited  wetting abilities.

      The small amounts of post-soldering board residue can  minimise cleaning
 problems or eliminate the need  for cleaning.  Toubin (1989)  found  that  Low-
 Solids fluxes  can  be  both efficient  and  cost  effective when  run  under  tight   '
 process  control.   A later report (Toubin 1991) has  indicated  that  many  of
 these fluxes may  cause corrosion, and SIR problems.  These and other problems
 have been corroborated by a  small number of users who  have reverted  to
 cleaning after many months of using  "No-Clean" techniques for medium-
 reliability applications.

      Synthetic activated (SA)  fluxes (more active  than rosin fluxes, but  less
 active, than many water-soluble  fluxes) were initially  designed to  be removed
 specifically with  CFC:113.   Compared to  rosin fluxes,  synthetic  activated
 fluxes, because of their activity, improve  the wetting by the solder.   SA flux
 residues must be  removed immediately after,  soldering.   SA fluxes have never
 held more than a  small share of the  market  and, since  the reduction  of  use- of
 CFC-113  and 1,1,1-trichloroethane solvents, this  share has been  reduced even
 further.  This loss of market share  is because SA flux has little  specific
 advantage except when used.with ozone-depleting solvents.

      There are a  variety of formulations for water-soluble  fluxes which
 usually contain relatively large percentages  of activators (compared with
 rosin fluxes), such as organic  acids, hydrochlorides,  hydrobromides  and amines
 dissolved in water or, more usually, alcohol  solvents.  Water-soluble  fluxes,
 in general, allow  faster soldering rates with fewer rejected  boards  due to
 solder defects and do not.require a  saponifier when cleaned with aqueous
 cleaning systems.  Water-soluble fluxes,  as currently  formulated,  are usually
 more corrosive than othe.r fluxes.  Subsequent board and component  damage  can
 only.be prevented  by  thorough and immediate controlled cleaning.   It may  be
 necessary not only to use purified water in aqueous cleaning  processes, but
 also to treat waste water.

      Although aqueous cleaning is used  in  a  number of electronics industry
 applications,  it 'is not approved for all applications.  In the past, U.S.
 military electronic assembly specifications did not allow water-soluble.
4  This specification consists of a list .of fluxes, rosin-based liquids, and
pastes-which have been approved for military use.   Specifically,  they  are
intended for use in the assembly of electronic  circuitry  and  electrical
equipment using tin-lead solders'.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 fluxes,  but such flux types were acceptable for British military-applications
 (DEF-STAN 00/10-3, Baxter 1989).  The latest revision to the U.S.  military
 Tri-Services soldering and assembly standard, MIL-STD-2000,5 Revision A
 (issued 14 February 1991), however, allows the use of non-rosin fluxes
 provided specific test and quality criteria are met.  Some specialised boards
 contain materials, such as polyimides and certain glazes in hybrid circuits,
 that are incompatible with aqueous cleaning that employs saponifiers.   Also,
 some water-soluble fluxes with certain polyglycol derivative constituents may
 be deleterious to the resin substrate of printed circuit boards particularly
 where the base material is of poor quality or has been incorrectly
 polymerised.  In this case, cleaning leaves a porous surface with flux
 residues absorbed into the surface of the printed circuit board.  These
 hygroscopic residues may cause
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                            Table II-1.  TYPICAL CIRCUIT  BOARD  ASSEMBLY CONTAMINANTS3
    Category  1
  Category 2
  Category 3
  Resin and  Fibreglass  Debris
  from Drilling  and/or 'Punching
  Operations
  Metal and  Plastic  Chips  from
  Machining  and/or Trimming
  Operations
  Dust
  Handling Soils
  Lint
  Insulation
  Hair/Skin
Flux Activators
Activator Residues
Soldering Salts
Handling Soils (Sodium and
Potassium Chlorides)
Residual Plating Salts
Neutralisers
Ethanolamines
Surfactants (ionic)
Flux Resin
Flux Rosin
Oils
Grease
Waxes
Synthetic Polymers
Soldering Oils
Metal Oxides
Handling Soils
Polyglycol Degradation
Byproduct
Hand Creams
Lubricants
Silicones
Surfactants  (non-ionic)
3 Contaminants may exhibit characteristics of more than one" category.
*
 Category 1 -Particulate                   '                .
 Category 2 -- Polar, ionic,.or  inorganic
 Category 3 -- Nonpolar, non-ionic, or organic
 Source:. ANSI/IPC-SC-.60 1987.
                       * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
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       2.4.1.1     . Low-Solids  "No-Clean"  processes

       These processes  use  fluxes  which may operate  according to a number of
different principles.   The original  types  were  simply variants of traditional
fluxes of the  DIN 8511 F-SW32 (halide-free rosin),  which were diluted to
typically one-half to  one-third the  solids content.   The ratio of activator to
rosin  was generally much higher.   These  early fluxes  were difficult-to-use.
These  were followed by a number of fluxes  with  greatly reduced rosin or
synthetic resin  content and an even  higher activator  content.-  These ones had
a slightly wider operating window.   Typical activators were adipic and
succinic acids which were  fairly  stable  at soldering  temperatures.   The next
generation used  flux systems  which sublimated at soldering temperatures.   This
allowed higher solids  content to  be  used for a  reduced volume of residues,
making for considerably easier soldering.

Advantages:

       •     Economical soldering
       •     No cleaning machine or space required'
       •     Environmentally easy  to  control
     .  •     Residues may be cosmetically acceptable      ^
Disadvantages:

       •     Restricted operating  window
       •     Reliability of assembly  needs  to be determined
       •     Higher-than-average retouch  rate
       •     Some types not suitable  for  conformal coating                  •
      •     Many types unsuitable for  high-reliability applications
      •     Solder-balling may be a  problem (not with hand-soldering)
      •     Cleaning not possible with many types
      •  ,   Double-wave soldering very difficult
      •     Residues may cause corrosion
      •     Residues may deteriorate electrical characteristics

      2.4.1.2     High-solids "No-Clean" processes
                  —i-*————_^^——_—_        (

      These use  traditional rosin-based  fluxes  to R,  RMA or RA specifications
or to DIN 8511 F-SW32  standards.
Advantages:
            Economical soldering
            No cleaning machine or  space  required
            Environmentally  easy  to control
            Easy soldering
            Cleaning usually possible,  if necessary
Disadvantages:
            Reliability of assembly needs  to be  determined
            .Generally unsuitable  for  conformal coating
            Many types unsuitable  for high-reliability  applications
            Automatic testing usually not  possible
            'Residues unsightly  and frequently sticky
            Pastes may tend  to  solder ball    .                     :
                    *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      2-15

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      •     Residues may cause corrosion
      •     Residues may deteriorate electrical characteristics        •'

      2.4.1.3     Controlled atmosphere soldering

      Controlled atmosphere soldering can be divided  into  two  types:   reducing
and inert atmosphere.  Technically, reducing atmospheres are difficult to
maintain and operate at ordinary soldering  temperatures but may  reduce the
needs of fluxes to extremely small levels,  leaving very little flux-related
contamination6.  Inert-atmosphere soldering is usually done under pure •
nitrogen with  strictly-controlled oxygen levels.  Inert atmosphere wave
soldering uses a flux which is sometimes called a preparation  fluid.   Early
types were based on a simple dilute adipic  acid solution in isopropanol.  The
latest generation sublime' on the solder wave so that  the small quantity  of
flux almost completely vaporise:  the relatively high vapour content may
recondense in  a polymerised form on the cooling circuit 'as the PCB leaves the
machine.  This leaves a microscopically thin protective coating.  Solder
pastes for controlled atmosphere reflow must be formulated to  have the right
ratio for the  correct rheological characteristics.  This makes them  leave
residues which are more visible than with wave soldering.
Advantages:
      •     Little dross formation on solder waves
      •     Lowest "No-Clean" residues
      •     Environmentally easy to control
      •     Residues may be cosmetically acceptable
      •     If required, aqueous cleaning is usually easy
      •     Minimum heavy metal salt formation

Disadvantages:

      •     Restricted operating window
      •     Reliability of assembly needs to be determined
      •     Higher-than-average retouch rate
      •     Of doubtful value for conformal coating
      •     Many types unsuitable for high-reliability applications
      •     Solder-balling may be a problem
      •     Residues may cause corrosion
      •     Residues may deteriorate electrical characteristics
      •,     High capital costs
      •     High costs of nitrogen

      2.4.2 Water soluble processes

      The use of water soluble fluxes and pastes represent  the most  economical
manner of soldering and cleaning.  Many major users have been using  them
continuously since the early 1960s.  Up to recently, most of the  fluxes used
at least some organic hydrochlorides as activators, with some form of  glycol
6  It has been stated on a few occasions that it is possible to solder in an
inert atmosphere without any flux, at all. This may be  theoretically  true
under ideal conditions: in practice, some way of reducing oxides  on component
leads and the PCBs must be present.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 derivative  as  a vehicle.   For about fifteen years, .it has been known that a
 few of the  glycol compounds have caused a deleterious effect on the insulating
 characteristics of some organic substrates.   This  effect has been studied but
 little major work was  done to characterise the phenomena and to avoid it.
 Recently, a number of  glycol-free products have appeared on the market,
 frequently  also halide and VOC-free (or nearly so),.   These have generally
 shown  themselves to be somewhat more difficult to  use,  but may be useful where
 a maximum Surface Insulation Resistance (SIR)  is essential.

       The aqueous method has proved to  be highly popular where the conversion
 away from a CFC-113 process has already been made  and a cleaning operation has
 been deemed essential.

       As with  all processes,  these do require  careful quality management.
 Less-than-perfect cleaning may produce  catastrophic  results.   Post-soldering
 cleaning may be done with just a simple water  wash followed by a succession of
 water  rinses.   For best results,  at the price  of a slightly higher
 manufacturing  cost,, the final rinses may be  achieved with deionised water, .
 particularly for high-reliability work  or where the  tap water quality is poor.
 Better results may be  obtained by using a chelating  solution for the first
 wash,  to ensure perfect solubilisation  of the  heavy-metal salts resulting from
 the  soldering  process,  again indicated  for high-reliability pro.cesses.
 Several advantages can also result from the  addition of a few percent of
 isopropanol to the last rinse water (Protonique 1993).

       2.4.2.1      Traditional water soluble  process

       This  process consists of soldering with  the help  of a water soluble flux
 using  organic  hydrohalide activators, containing little or no water  in the
 solvent base.   The high flux activity, makes  this process  easy-to-master  with
 extremely low  retouch  rates.   The cleaning process is easy and the overall
 results are suitable for  most applications.

       One problem common  to all  pure water processes is that of retouches and
 hand soldering.   Water  soluble flux cored solder wire of  all  types is
 available from many manufacturers,  but  are not  popular  because of the fumes
 they produce.   Good air extraction from the  soldering zone is highly
 recommended, so  that the  same cleaning  process  may be used for mass-soldered
 and 'for retouched boards.
Advantages
            Lowest cost of all soldering/cleaning processes
            Easy soldering
            Low retouch rate
            Very good residual cleanliness, even under SMDs
            Water treatment easy and cheap
            Wide range of machines available
            30 years of track record
7  All organic fluxes of all families contain volatile organic compounds
(VOCs). Although the solvent system is usually quoted as the main source of
VOCs,- the .activators, surfactants and vehicles also are the sources of
emissions of VOCs at soldering temperatures.

                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHES1VES REPORT *
                                     2-17

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Disadvantages

      •     Good cleaning quality essential  - no half measures
      •     Possibility of slightly poorer SIR
      •     Users are afraid to try it                           \

      2.4.2.2     "Glycol-free" water soluble process

      This relatively new substitute process has raised some  interest  in
military circles.  The prototype fluxes of this type were developed about
twenty years ago.  One German manufacturer marketed a flux using citric acid
as activator, a triol as vehicle, a small amount of a non-ionic surfactant and
alcohol, with a small quantity of added water, as a solvent.  Over fifteen
years later, an American company developed a flux consisting  of citric acid, a
small amount of non-ionic surfactant and water.  This latter  development
dispensed with the triol and the alcohol to reduce the VOC content, an added
advantage in regions with rigorous VOC legislation, but-at the cost of
narrowing the soldering "windpw".  Another multinational flux manufacturer
announced in 1989 another type of polyglycol-free flux  in both low VOC and
"normal" versions, employing completely different vehicle and activator
chemistries.  Some of the fluxes in this range may be employed as "No-Clean"
products or for water cleaning, according to the individual circuits being
soldered.
Advantages
      •     Low cost soldering/cleaning processes'
      •     Very good residual cleanliness, even under SMDs
      •     Water treatment easy and cheap
      •     Wide range of machines available
      •     No SIR deterioration
     ••     Some products low VOC

Disadvantages

      •     Good cleaning quality essential - no half measures
      •     Some potential users "afraid" of trying it
      •     Reduced operating "window" of soldering operation

      2.4.3 Saponification processes           •

      Saponification is a chemical reaction which modifies insoluble rosin
into a water-soluble rosin soap which can then be removed in a similar washing
process (2.4.2) as used for water soluble processes.  As it is a chemical
process, it is necessary to use reactive products, generally highly alkaline
mixtures based on monoethanolamine. .These aggressive products require careful
handling.   For this reason, this process has not been as popular as the
excellent results may suggest.  Cleaning quality has been shown to be
outstanding (Grossmanh 1993) ,  but this process works best with thin residue
layers.  Although slightly more expensive than water soluble flux processes,
the overall cost is acceptable.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     2-18

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 Advantages
       •      Reasonably low cost soldering/cleaning processes
       •      Very good residual cleanliness, even under SMDs
       •      Water treatment reasonably easy and cheap
       •      Wide range of machines available
       •      No need to change flux type in many cases
       •      Over 25 years of good track record

 Disadvantages

       • •     Good cleaning quality 'essential - no half measures
       •      Users are reluctant to try it
       •      Health and Safety concerns
       •      Thick rosin residues may require long cycle times
       •      Potential incompatibilities with amphoteric metals and polyimide
             substrates •
       •.     Selection of most suitable saponifier may require much work

       2^4.4 Hydrocarbon-Surfactant (HCS or HC/S) Processes.

       Also - incorrectly - known as "semi-aqueous" processes, HCS methods have
 not seen the commercial success originally forecast.   This is due to high
 drag-out losses, up to 4 g.dm   with  densely  populated  SMD circuits  (Scolari
 1993) ,  high equipment cost, VOC concerns, combustibility,  difficult recovery
 and water treatment etc.  Nonetheless, there, remain many niche applications
 where  HCS processes may be suitable and economical.

       The basic principle is simple and effective.  Rosin flux based soldering
 residues  are solubilised in an.organic solvent whose  vapour pressure is fairly
 low.   The contaminated solvent is then removed by a full water wash, usually
 very similar as is required for cleaning off water soluble fluxes (2.4.2).
 This immediately shows that the cleaning equipment must therefore be designed"
 with both the. solvent and aqueous phases in mind. • Chemically, the solvents
.may either be natural derivatives, such as terpene'-based substances, or
 synthetic hydrocarbons and derivatives.  There is no  specific advantage in
 using  the natural products - even though some may be  derived from citrus
 fruits,  for example - from the points of view of health, safety and', the
 environment.  In fact, many (but not all) synthetic products are considerably
 less toxic than those made from citrus fruits.

       There are two basic methods used in HCS processes and the equipment for
 each is  completely or partially incompatible with the other.  These can be
 considered as ".separable" and "miscible" types.  Separable types are based on
 light  hydrocarbon derivatives with a specific gravity of less than about 0.9
 and which do not mix with water.  In order to solubilise it in water, it is
 blended with a surfactant which allows an unstable emulsion to form.  The
 water  emulsion,  if allowed to remain still, will separate  out so that the
 solvent will float on the surface of the water/surfactant  mixture.  It can
 thus be  easily recovered for a partial recycling, but the  composition of the
 separated product is different from the original solvent.   Retaining a' steady
 process may therefore be problematic.

       The miscible HCS solvents may be subdivided.into those which are blended
 with hydrocarbon solvents and more stable surfactants,  producing a permanent


                     * 1994 UNEP SOLVENTS, COATINGS, AND AOHESIVES  REPORT  *
                                      2-19   .

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 emulsion,  and  those which  are  hydrocarbons  or derivatives which have,  within
 themselves,  a  surfactant property,  often forming a non-micellar solution.

      The  cleaning part of the process  is the same with both categories of HCS
 products.  The main difference is with  the  waste water treatment and recycling
 processes.

      The  cleaning quality or  both  types of process may be very good,  but
 tests have shown  that both water soluble flux and saponification processes are
 even better  (Grossmann 1993).   It may be possible that the miscible types  are
 marginally better, although the difference  would likely be small.

      With separable processes, the initial waste water treatment and/or
 recycling  is done by the separation.  The water  then has to be  treated to
 remove  the surfactant, the heavy metal  salts and residual solvents.   This  is
 done initially with membrane separation (different membranes -may be required
 for each solvent  type), followed by active  carbon and deionising resin
 polishing.   The water quality  is high enough for recycling up to about 80% of
 the total water requirements,  but the process is expensive and  it does not
 include  the  treatment of the pollutants.  The problem is even more difficult
 with the miscible types, where the.pollutants are almost impossible to remove
 economically from the waste water.   A recent development (Treacher 19.93)
 attempts to  use evaporative separation,  but it is a very energy-intensive
 method  and the recovered solvent has a  considerably different composition
 compared to  the virgin material.  It should be stated that most miscible
 solvents produce a waste water with high BOD5s,  which  may'not always meet
 water quality  standards.

      It is possible that  some of the less  popular types may simply disappear
 from the market within the next two or  three years.   Persons considering these
 processes would be well-advised to  ensure that back-up products exist  should
 their original choice be withdrawn  from the market (one major manufacturer and
 one major distributor have both already dropped  the commercialisation  of such
 products).

      2.4.4.1     Separable HCS processes

 Separable HCS  processes are possibly easier to manage  as an overall  system
 with recycling of the water and the solvent itself.   To achieve this
 separation requires equipment  which is  very costly to  install,  run,  and
 maintain.  As  such, this process is easier  to amortise f.or very large
 production rates where' the equipment is  expected to work at near-maximum
 capacity 24 hours per day  and  7 days per week.   Smaller installations  without
 integral recycling may also be used, but may present other problems, outlined
 earlier.
Advantages:
            Good cleaning quality
            Slightly more forgiving of poor cleaning  than many  other  types
Disadvantages:
            Heavy consumption without recycling
            High capital costs with  recycling
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                      2-20

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      •     High  maintenance  costs
      •     Combustible!  .
      •     Separation  may  be at  temperatures  above  the  flash point
      •     Health  and  Safety concerns
      •     VOC concerns

      2.4,4.2     Miscible  processes

      Other than  for  industrial cleaning,  there  is an important  niche  market
for this  type  of  process: field and service, cleaning.  One  multinational
soldering product manufacturer offers a  cleaning kit consisting  of such a
solvent packed in a non-aerosol spray bottle with an adjustable  nozzle capable
of a jet  or fine  sprays.  For low. volume industrial  cleaning,  this type of,
process may be suitable without water treatment,  but only on  condition of
prior approval of the water authorities:   In view of. the high quasi -
irrecoverable  drag-but  losses, this process  is very  costly  for high-volume
production.
Advantages:
      •     Good  cleaning  quality
      • •    Slightly more  forgiving of poor  cleaning  than many  other  types
      •     Very  adaptable  to  low-volume  cleaning
      •     Some  products  practically non-toxic

Disadvantages:

      •     Heavy consumption  without recycling with  water pollution
      •     High  capital costs with recycling
      •     High  maintenance costs
      •     Combustible
      •     VOC concerns

      2.4.5 HC and derivative  processes.

      Straight HC solvent  cleaning use flammable or combustible solvents.  The
processes can be  divided between those using volatile and flammable solvents
such as light alcohols, and heavier, combustible, substances.  Light  alcohols,
by themselves, effectively  remove rosin residues but  many other contaminants,
such as heavy metal salts,  may not be correctly eliminated.  Some proprietary
blends of heavier solvents  are remarkably effective cleaners when correctly
used but their low volatility  render them extremely difficult to'dry  off.
Drag out losses are very high.  As for HCS processes, these may reach as much
as 4 g.dnf2  on densely populated SM circuits, even with.air-knife  excess
solvent removal.  Energy consumption for  drying may be very high with solvents
whose boiling points exceeding about 135°C.

      2.4.5.1     Light HC  solvent processes

      This is occasionally  used for very  small scale  cleaning (i.e. circuits),
using open trays  and brushes.  They represent distinct fire and toxici.ty
hazards.  For full production  scale cleaning, machines with, appropriate.
flameproofing, including nitrogen purging, are available.  For correct
cleaning quality, many light solvents, including alcohols, saturate at
extremely low levels of heavy  metals, particularly lead salts.  This  means


                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                                     2-21

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 that  heavy-duty reflux distilling of the solvent is necessary to ensure enough
 pure  material  is present for the last rinse.   This is a very costly process.
 Advantages:
       •      Low-cost  solvents
       •      Generic solvents readily and universally available .
       •      Easy-to-repurify by reflux distillation

Disadvantages:

       •      High  capital  cost  for  machinery
             High  energy requirements
       «      Good  cleaning quality  difficult to ensure consistently
       •      Anti-fire/explosion precautions costly
       •      Solvents  are  VOCs

       2.4.5.2      Heavy HC solvent processes

       These  are arbitrarily separated from light solvent processes when the
boiling point of  the  solvent exceeds about 120°C and the flash point is higher
than about 50°C.

       Those  based on  ethylene  diglycol type derivatives  (also  usable as
miscible HCS solvents) are very effective cleaners without  much evaporative.
loss.  However, they  have an extremely low vapour pressure,  with flash points
often  in excess of 100°C.   This renders them very difficult to dry off.  Tests
with one type have shown  that  such solvents may require  time and energy
requirements greatly  exceeding those of water under the  same -conditions by a
factor of five or more (Scolari 19.93) .   Drying temperature  should be limited
to at  least  20°C  under the flash point.   The drying process may be aided by a
final 'perfluorocarbon vapour phase stage (2.4.6)  but this is not recommended
due to the emissions  of global warming gases.   The process,  may consume high
quantities of solvent by  drag-out  losses.
Advantages:
      •     Good cleaning quality possible
      •     Low fire hazard
      •     Low toxicity (some products)       '                               .
      •     Easy to handle and use
      •     High rosin loading possible

Disadvantages:

      •     Expensive solvents
      •     Difficult and expensive drying
            VOCs
      •     Difficult to repurify and recycle  the  solvents

      2.4.6 Permitted halocarbbn processes

      There are three halocarbon processes which may  be  mentioned,  using non-
ozone depleting chlorinated solvents, HCFC and HFC blends and PFC  drying
processes.


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     2-22

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      All  three  of  these  processes  demonstrate  grave  environmental and other
disadvantages.   Practical experience  in many locations  have shown that there
are very few  cases  where  the  use  of these  environmentally disadvantaged.
products present a  real benefit over  more  benign processes for the electronics
industry,  either economically, or  technically.

      At best, they can,offer only  a  temporary,  technically doubtful  and
costly alleviation  of  the problem.  Most of  those companies in the electronics
industry that have  adopted them have  chosen  HCFCs and they are generally  aware.
that this  process is temporary and  may  not be either  entirely suitable or
economically viable.   However, it may offer  them the  time necessary to choose
a more suitable  process.

      2.4.6.1     Non-ozone-depleting .chlorinated processes

      Theoretically, all  chlorinated  solvents are ozone-depleting,  although  a
number of.them have negligible ozone-depleting  potentials.   These  include
perchloroethylene (tetrachloroethylene)  and  trichloroethylene.   Solvent blends
containing perchloroethylene  have been  proposed  as  "cold  flux removers".   To
date, there is no evidence  that these offer  any  real  technical  advantage  over
other processes.  On the  other hand,  they  are known to  cause  problems  with
many synthetic compounds  such as  a  number  of plastics and even  printed circuit
substrates.  As  a result,  their use is  relatively limited.   They have
occasionally been employed  with "kiss"  cleaning  machines  (bottom-surface.
brushing machines)  to  remove  sufficient  flux to  allow automatic  test machine
probes to  contact the  metallic surfaces, without  truly  cleaning  the
assemblies, but  this is a niche market,  possibly  better resolved by using
certain qualities of "No-Clean" flux.
Advantages:
      •     Easily obtained, low-cost solvents
            Zero-to-low OOP                                           •   '  .
      • '.   Traditional method

Disadvantages:

      •     Health and safety concerns
      •     Some blends may be VOCs and/or have high GWP
      •     Cleaning quality often mediocre
      •     Plastics and PCB substrates often sensitive to solvent
      •     "Cold" cleaning produces high drag-out losses
      •     "Cold" cleaning blends non-azeotropic
      •     High boi'ling points preclude vapour defluxing in some cases

      2.4.6.2     HCFC Solvent processes

      Except for the very rare application, HCFC solvents should 'never be  used
for cleaning an electronics assembly.

      All HCFCs deplete the ozone layer.  They are regulated under  the  .
Montreal Protocol and those controls may become more stringent  until  a total
phaseout is achieved.  Two HCFC solvents are otherwise.suitable for  '
electronics cleaning.  ,HCFC-141b has a high ODP  (comparable with  that- of
1,1,1-trichloroethane) and may be' subjected to ..more severe restrictions  in the


                    * 1994 UNEP SOLVENTS, COATJNGS, AND ADHESIVES REPORT *
                                     2-23

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short term.  It also attacks many plastics materials  and has  a  low boiling
point with a high volatility.  This  is  the least  recommended  of HCFC  solvents
for this work.  HCFC-225  is a blend  of  isomers  and has  characteristics  quite
similar to CFC-113 except for a  lower ODP and a higher  cost.  It is the
nearest solvent we have to a "drop-in"  replacement of CFC-113,  even to  the
extent of blends with similar characteristics.

      The equipment, when using  HCFCs,  must  always be suitable  to minimise
emissions.  This is not only to  prevent unnecessary ozone  depletion,  but also
from a purely economic standpoint as the cost of  these  solvents is high.   Any
unnecessary losses therefore compromise their economic  viability.   Above all,
they should never be used, in an  open-top vapour degreaser,  particularly if the
model is more than two years old.

Advantages:                    •

      •     Process similar to the familiar  CFC-113 vapour defluxing

Disadvantages:   '             '

      •     Ozone depleting
      •  -  Some blends may be VOCs  and/or have a high  GWP
      •     Requires expensive near-zero emission machinery
      •     Forbidden in  some nations
      •     Future legislation uncertain in  some  others
      •     Some solvents expensive
      •     Doubtful economic viability
      •     Cleaning quality doubtful  (according, to solvent)
      •     Attacks some  plastics (according to solvent)
      •     Transitional  substances  only


2.5   MACHINERY FOR ENVII   "NTALLY  RESPONSIBLE SOLDERING  AND CLEANING

      All electronics solu-^ing  and  cleaning is detrimental to  the
environment.  It is important that those selecting equipment  choose types
suitable to do the required work, yet cause  a minimum amount  of environmental
harm.  This section will  give a  brief review of some  of the risks that  occur
with different process types.

      2.5.1 Conventional wave soldering

      While wave soldering is generally not  a very polluting  process,  it is
not entirely benign either.  The worst  pollutants are those derived from the
flux during the preheating and soldering stages.  The fluxes  generally  contain
organic solvents, usually light  alcohols.  These  are  evaporated,  mostly during
the preheat stage, but residual  amounts during  the actual  soldering.  There is
little decomposition of these compounds which are usually  almost 100  percent
emitted.   They are not very dangerous to the environment,  due to their
hydrophilic nature which gives them  a very short  atmospheric  lifetime.
However,  a few nations or regions do consider them as VOCs.   The cheapest way
of reducing their emissions is to use cold water, in  a  small.scrubbing  tower,
between the machine exhaust and  the  outside  air.  The resultant water/alcohol
xixture may then be treated tr. separate the  components  and thus recover the
• ilcohol (this is not necessarily an  economical  recovery)..


                   * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES  REPORT *
                                     2-24

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       Also from the flux, activators and vehicles are often volatilised,
 sometimes unaltered, sometimes decomposed, as well as the solvent  system.
 These may be hydrohalide acid gases, amines and amino acids,  linear or cyclic
 carboxylic acids, oxygenated hydrocarbons or derivates of these substances.
 Rosin, for example, may partially decompose into toxic aldehydes.  In
 particular, Low-Solids "No-Clean" fluxes are often designed to deliberately
 volatilise or sublime so as to minimise the quantity of post-soldering
 residues.  All these products, with the exception of hydrohalide acid gases,
 must be considered as VOCs.   The quantities emitted per machine may not be
 very large, but the global emissions must amount to thousands of tonnes per
 year.  Some products may even be considered as toxic or otherwise  dangerous to
 the environment.   Again,  a water scrubber will reduce 'effectively  the quantity
 of pollutants emitted,  followed, if necessary, with an active carbon filter.

       A third class of pollutants derived from wave soldering are metal oxides
 and salts.   Tin and lead in the solder wave oxidise on the surface.  This film
 of oxides falls into the solder bath,  breaking up as it does so.   Turbulence
 at the. surface causes a small quantity of these oxides to be projected as an
 aerosol- dust into the air.   If there are flux activators in the air,  as well,,
 these oxides may be reduced into metal salts,  some of which,  finely divided,
 may be particularly toxic,  even if the quantities are almost infinitesimal.
 Again, a water scrubber will remove most of this kind of particle,  but the
 water may require more  rigorous treatment.

       Metallic particles,  often termed microspheres or microballs,  are
 frequently produced in  relatively,large quantities and may adhere to  the
 surface of the board.   These are mostly removed in subsequent cleaning and may
 cause problems in the cleaning product ifxnot carefully mechanically  filtered.

       2.5.2 Controlled  atmosphere wave soldering

       The pollution produced from controlled atmosphere wave  soldering is
 "generally very similar  to that from conventional soldering,  except  that the
 oxidation of the  solder is  much reduced.   There is therefore  relatively little
 metallic salt formation.   The quantity is not reduced to zero, because of the
 oxides present on the board  and component leads before the soldering  process
 commences.   These are not completely reduced to salts before  the  passage into
 the wave,  so a finite amount of dross  is always present.   Microballs  are also
 more frequently produced  with this process  but,  as the boards are rarely
 cleaned,  they do  not Represent a major hazard in the cleaning process,  even  if
 they may cause electrical problems.  A newly .developed-controlled atmosphere
 soldering process uses  a  reducing gas  plasma in place of fluxing.   It is not
 yet sure, to what  extent this can reduce organic contaminants  on the components
 without attacking the organic substrate.
       2.5.3  Infra-red etc,  solder paste reflow
       This  section also includes most other types of reflow,  with the
 exception of vapour phase and liquid immersion types.   The pollutants produced
 are  generally similar to those produced by wave soldering.  In addition,
 chemical  agents  in the pastes to establish the right rheplogical
 characteristics  add to the spectrum of evaporated chemicals.   These may take
•numerous  forms but all such emissions must be considered as VOCs.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      2-25   •     ;

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      2.5.4 Vapour-phase solder paste reflow

      This is possibly one of the worst pollution  generators  in the
electronics industry, after CFC-113  cleaning.  There  are  several conceptions
of the process, but none are better  than  the  others.   Fortunately;  it is
losing popularity and few new equipments  are  being put into service.

      The main problem with this process  is analogous to  that of CFC-113
cleaners.  A heavy vapour is used to allow the parts  to reach the soldering
temperature.  This vapour is not easily contained  and the methods used to
contain it often acerbate the problem.  The vapour is a perfluorocarbon (PFC)
compound with a boiling point in the range of 215°-260°C.  As far as  is known,
PFCs have no effect on the ozone layer but -they  are among the worst
"greenhouse gases".  Furthermore, they have atmospheric lifetimes of  500  to
10,000 years.  The breakdown mechanisms are unknown and there is a finite  risk
that they may cause unforeseen problems within a few  centuries if allowed  to
accumulate in the atmosphere.  For this reason alone,  this process  is not
recommended.

      There are three major methods  used  to reduce emissions  of the expensive
PFC reflow medium, none of which are completely  effective,•as the medium  is
often entrapped under the components on the assembly.   These  are the
mechanical machine design, the use of a CFC-113  secondary vapour blanket  and
the use of a more volatile, less expensive, PFC  secondary vapour blanket.   The
latter has only an economical effect, as  the  PFC used for the blanket is  as
bad a "greenhouse gas" as the primary vapour.  CFC-113 is, of course,  not
acceptable because it is a regulated substance under  the  Montreal Protocol.
No economical machine design can reduce the emissions of  the  PFC to an
effective level.
      2.5.5 Hot liquid  immersion  solder paste  reflow.
      This method uses a glycol derivative heated  to  the  fusion  temperature -as
the heating medium.  It has a number of advantages, especially for  thick film
circuits.  A good proportion of the paste residues  actually  dissolve  in the
medium, so that the cleaning process, using  a  simple  water wash,  becomes easy.

      The medium starts to decompose fairly  rapidly,  evidenced by a visible
carbonisation, but this does not become serious until the end of the  useful
life, of the product, typically 30-40 hours at  the  reflow  temperature.   Even
though the vapour pressure of the medium is  so low  at room temperature  that  it
may not even be considered a.VOC, the evaporation  at  fusing  temperature is
quite high.  This will contribute to tropospheric  ozone and  smog under  the
right weather conditions. The process is quite dirty_as a sticky polymer tends
to condense all around the machine.  This makes a  good extraction system
essential, designed to minimise cooling at the liquid-air interface.  The
extracted air can b'e water-scrubbed: mechanical filters are  useless as  they
.log very rapidly.  The water in the scrubber  tower may be contaminated to a
heavy degree but may be used as the first wash water  for  the reflowed
assemblies.  The contaminated water will have  a high  BODc and some  authorities
•say not permit its discharge into sewage.  The heavy  metal content  may  be
  •ceptable as much of the metal salts will remain  in  the  fluid.   This would  • .
'•'quire analysis .before allowing it to discharge.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     2-26

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       The spent fusion fluid must be considered as a hazardous waste and be
 disposed of correctly.  Apart from the heavy metals, the product-will have
 become heavily decomposed and polymerised.  It will be largely non-
 biodegradable, either in water or soil.  It cannot be effectively used as a
 fuel unless the metal content is removed and the residues crac.ked to lighter
 hydrocarbons.  This can be a severe limitation to its use.

       The paste type used in this process is usually water-soluble. Rosin will
 dissolve reasonably well in most of the commercial fluids, but an accumulation
 of rosin residues will reduce the useful life of the product and make it even •
 more difficult to eliminate.

       2.5.6 Aqueous cleaning (conventional water-soluble fluxes)

       The first wash water of straight water washing will contain heavy
 metals, usually to prohibitive levels.  Its pH may also be lower than is
 permitted by many authorities.  It will also contain glycols and surfactants
 which will both increase .the BOD5,  but generally not to severe levels with the
 levels commonly formed.   The water may be treated by any conventional method
 to remove the metal content and neutralised with a basic solution.  This would
 allow the waste water to be discharged, assuming the biodegradability was
 acceptable.                                   '

       Complete recycling of the waste water is nearly impossible:  the maximum
 is probably about 75 to 80 percent, in most cases. ,  The remaining 20 to 25
 percent represents drag-out losses, evaporative losses, membrane concentrate
 solute, diverse filter replacement losses, deionising column regenerating
 solution and rinse waters and other water usage.  Any water treatment using
 membrane or deionising techniques to remove heavy metals does not really help
 the situation: at the best, it displaces the problem to another level, as the
 metals are still present either in the concentrated waste water and in the
 resins.- On. regenerating the latter, the metal is removed and re-enters into
 an aqueous solution.  If the resins are mixed bed, this is usually done off-
 site and the regenerating station must be warned that heavy metals are
.present.  The one advantage in concentrating the heavy metal salts in waste
 water is that they become easier to treat than in a highly diluted form.

       2.5.7 Aqueous cleaning (glycol-free water-soluble fluxes)

       The environmental problems with so-called glycol-free fluxes are
 identical to those of conventional, water .soluble fluxes.  Despite the term
 "glycol-free" some fluxes of this type do contain certain benign glycol
 derivates, even if they do not contain the polyglycols suspected of/causing a
 reduction of surface insulation.resistance of some substrates.  Some of the
 surfactants used to allow such fluxes to foam or to improve the wetting of the
 flux are very closely.related to some .of the polyglycol derivates.

       Some of these fluxes also contain tribasic carboxylic acid activators,
 such as citric acid.  These are known to have a chelating action on heavy
 metal salts.   As a result, the latter, may be more difficult to remove until
 such time as the acids start to biodegrade, which may take a considerable
 amount of time.
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
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      As  a  general  rule,  these  fluxes  are  no  better environmentally than their
 conventional  counterparts,  as far  as the cleaning process  is  concerned,  and
 may present greater difficulties.

      2.5.8 Saponifier  cleaning

      Saponifiers based on  monoethanolamine operate normally  at around 55°C.
 At this temperature,  there  is a certain amount  of evaporation of the amine  and
 the co-solvents.  The latter are usually VOCs,  but the  amines,  being basic,
 tend to react rapidly with  acid gases, such as  carbon dioxide,  especially in
 the presence of humidity.   Because of  this, their atmospheric lifetime usually
 is. very short.  The reaction products  are  generally without effect,  being also
 very hydrophilic with a very short folded-e lifetime.   They may form nuclei
 for mist  formation  if the atmospheric  humidity  approaches  saturation.  This
 must not  be confused with ozone and smog formation due  to  the' photochemical
 reaction  between nitrogen oxides and VOCs.

      2.5.9 HCS solvents    .

      HCS solvents  may  be among the most polluting methods  of cleaning.
 Practically all the solvents are classed as VOCs  at normal  operating^
 temperatures.  Most of  the  emitted vapours can  be collected from all parts  of
 the machine (including  the  wash and rinse  sections' and  the  separator,  if so
 equipped) and economically  reduced by  a water scrubber.

      The most polluting, aspect of the HCS processes is  the quality  of the
 wash and  rinse waters.  Even if gravitational and/or membrane separation
 techniques  are used,  a  considerable quantity  of solvent  remains either in the
 water when  the machine  is drained  and  the  concentrate contains  considerable
 proportions of water.   Many commercial machines, .including  some quite  large
 and expensive ones,  are equipped with no means  of separation,  meaning  that
 most of the large quantity  of dragged-out  solvent ends up  in  the waste water.
 This is especially  critical with solvents  that  actually  form  a  stable  mixture
 with water, where no  economical form of separation can possibly work,  except
 for the very largest  installations.  One commercial machine,  designed  for use
with a high-boiling point solvent,  developed  in Great Britain,  concentrates
 the mixture by evaporating  off  the water.  However,  this is inefficient and
 energy-intensive:   as some  of the  components  of the solvents,  themselves
 zeotropic,  form an  azeotrope with  water, the  resultant residue  contains  water
 and has a composition wildly different from that  of the  original solvent.   It
 is likely that the  recovered solvent is not extensively  re-usable and  that
 considerable quantities of  some of the components are emitted.

      Solvent drag-out  losses can  be very high, of the order  of 100-500 g/m2
 of printed  circuit  assembly depending essentially on the type and density of
 the electronics components.  Many'machines are  equipped with  air knives  on
exiting from the solvent phase  of  the cleaning  process.  This is insufficient
 to significantly reduce the problem: if the energy is sufficient to  eliminate
more than a few percent of  the  solvent residues,  most of the  solvent will be
atomised or vaporised,  thus .displacing the problem from water to ai'r.   In
practice,  with a machine which  air-knives  the PCBs without  causing undue
losses,  only the superficial solvent, representing typically  about 50-100
g/m2,  will be recovered.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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       The solvent in the wash water is usually claimed by the manufacturers  to
 be "biodegradable".  In reality, many HCS solvents have ,a very high BOD5 and
 or COD, sometimes exceeding national limits or recommendations even in small
 proportions.  This aspect should be carefully examined before choosing such  a
 process or,  at least,' a given solvent.

       Even if gravitational separation is employed, practically all the
 surfactants  -- often up to 10% of the solvent volume.-- and dissolved heavy
 metals remain in the water.  The only way to improve separation is by active
 carbon filtration to handle.the large quantities of surfactant followed by
 traditional  methods of deionisation or precipitation to remove the metals.
 Membrane techniques may not be able to separate the two pollutants from' each
 other

       The most difficult problem is the disposal of the used solvents.  These
 contain, as  well as the original components,  heavy metals, rosin residues,
 activators and other contaminants resulting from the assembly being cleaned.
 They are therefore considered toxic waste.   Since about one-third of such
 waste is composed of contaminants from the assemblies being cleaned, the
 composition  is completely unknown and the heavy metal content is-likely to be
 quite high.   The only safe way to dispose of .these products is to incinerate
 them in a kiln designated for the disposal of combustible chemical waste.
 There exist  a handful.of special purpose-built kilns.for this throughout the '
 world,  but their use is expensive.   More usual is to mix the solvent into
 cement kiln  fuel with approved installations.   Most of the incombustible
 residues (heavy metal salts)  are incorporated in minute proportions into the
 cement.   They do not alter the cement properties and they eventually become
 encapsulated in a mass of solid cement or concrete where they are harmless.
 The  remainder of the salts are collected by the fly ash electrostatic
.precipitator whose contents are usually added to the limestone feeding the
 kiln.   Any acids or other volatiles from decomposition of the activators are
 collected in a water scrubber mounted in the  flue.

       Some manufacturers of HCS solvents try to make light, of the disposal
 problem of the used product.   For example,  it has. been suggested that the
 spent solvent may be added to heating fuel  oil.   The problems that could
 result from  such advice may be:

       •      clogging of the burner nozzles by burnt rosin, causing poorly
             controlled combustion
       •      acid vapours could attack burner parts, boilers and flue linings
             if they are of unsuitable materials
       •      all the heavy metal  salts would be emitted into the atmosphere
       •      the optimum fuel:air ratio will be upset producing excessive
             emissions of NO^ gases  and soot
       •      in summer,  when~the fuel consumption drops, the problem tends, to
             become acerbated by excessive quantities of solvents

 This  prac'tice,  where it is not expressly forbidden by law,, should be
 discouraged.

       2.5.10      HC solvents  and derivatives

       As a general rule,  all  straight solvents are VOCs and their disposal
 must  be  done according to the criteria of common sense.  Both these subjects


                    * 1994 UNEP SOLVENTS, COATINGS,  AND ADHESIVES REPORT *
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form part of the last section  (2.5.9) and their treatment  is more-or-less
identical.  They normally engender no water pollution problems, by  definition.

      The only exception to this is with the use of  light  solvents,  such as
the lower alcohols.  The vapours from these form a distinct fire  and explosion
hazard, as well as being VOCs.  Appropriate action should  be taken,  in
conjunction with the local fire protection agency and insurance company, to
prevent any emissions from creating an unforeseen hazard.  The best method is
to ensure that the emissions are as low as is humanly possible.

      2.5.11      Permitted halocarbon solvents

      Wo matter their composition, all halocarbon solvents are dangerous to
the environment, being any combination of ozone-depleting, global-warming,
toxic, VOCs and generally undesirable.  It is the responsibility  of the user
to reduce their emissions to virtually zero at all times by suitable machine
design and housekeeping practices.  There is really  no reason why they should
be used for any purpose within the electronics industry, with the possible
exception of a very few minor applications, representing perhaps  the
production of one establishment in tens of thousands.

      Unfortunately, this is unrealistic.  There has been  economic  pressure to
use HCFC-141b in place of CFC-113.  Some vendors claimed that it  could be used
in existing machinery without modification of the equipment or the  working
practices.  The result was that emissions into the atmosphere increased
significantly.  Although this solvent has only about one-fifth the  ODP of CFC-
113, the net result would be the unnecessary emission of an ozone-depleting
substance.  As HCFC-141b mixtures are poor defluxers and can attack some
electronics components,, .there is no reason why it should be used  for this
application.  If, for any reason, an HCFC solvent must be  used for  defluxing,
then an HCFC-225 mixture would be more suitable.  Also, since it  is more
expensive, users will have the incentive to minimise emissions.

      The Solvents, Coatings and Adhesives Technical Options-Committee does
not recommend HCFC-141b for defluxing in. the electronics industry under
Multilateral Funding-.             •

      The measures to be taken to minimise emissions of .HCFC-225  and other
halocarbon solvents are described adequately in past editions of  these reports
(UNEP 1989,  1991).
2.6   PRODUCTION MACHINERY AND MATERIALS

      The choice of machines for assembling and soldering printed  circuit
boards is too large to catalogue all that are available.  Instead,  discussion
8  HCFC-141b has a high ozone depletion potential (ODP) of 0.11 which is
equivalent to the 1,1,1-trichloroethane ODP of 0.12 and it is  controlled under
the Montreal Protocol.  Future changes may further restrict its use  or advance
its phase out dates.. HCFC-141b should therefore 'only be considered  as a
replacement for .CFC-113 in specialised application where no  other substitute
or alternative exists.

                   * 1994 UNEP  SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 will focus on the impact they may have on the overall process when
 substituting new methods for traditional ones.

       2.6.1 Conventional wave soldering machines

       When choosing a new wave soldering machine or adapting an existing one,
 it is important to look at the means for fluxing.  Traditional rosin fluxes
 usually foamed very well, so that foam application was the choice of,
 predilection.   This was simple,  effective, and inexpensive.  Originally, air
 was pumped in through a porous,  cylindrically shaped stone.  To obtain more
 uniform results, this was replaced by synthetic sintered stones.  Some of
 these were slowly attacked by some fluxes and sintered plastic'"stones" are
 now the rule,  being cheap and long-lasting.   They are,'available in different
 pore sizes and the choice may become critical according to the flux
 characteristics with modern fluxes.

       As a general rule, "No-Clean" Low-Solids fluxes do not foam very well
 and are sometimes difficult to use in a foam fluxer.   If problems are
 experienced, one should try different stone porosities.  Having determined the'
 best one,  if the foam head is still inadequate, it may be necessary to modify
 the chimney geometry with either a new chimney or polypropylene .inserts,
 fashioned to suit.  These should restrict the form to as narrow a chimney as
 possible,  6-10 mm internal width at the top and 2-3 mm more than the stone
 diameter at the bottom being ideal.

       Another approach is to replace a foam fluxer with a fine plastic mesh
 drum which turns with the bottom third in the liquid flux.   At the top, an
 air-knife blows the flux held by capillary action as fine droplets onto the
 board.   This is possibly more reliable than foam fluxing in difficult cases.

       In both of the previous methods, there are considerable changes in the
 flux composition with time, as the air used exaggerates the evaporation of
 solvents and may add humidity, to the flux.  The solvents have to be replaced
 to maintain the correct flux characteristics.  With conventional fluxes, this
 replacement can be calculated and checked easily by simple gravimetric means.
 With Low-Solids fluxes, this is  not possible as the difference in density
 between the flux and the solvent is small and the results can be easily
 misinterpreted by the presence of humidity absorbed from the .atmosphere or the
 air used in the fluxer.  The only reliable low-cost method is by titration and
 some flux manufacturers provide  simple titration kits for Use with their
 fluxes  for maintenance.

       Another fluxingtmethod is  to spray the flux evenly over 'the board using
 oscillating or multiple spray heads.  These must produce a fine, uniform
 deposit without undue quantities of mist which would not only be wasteful but
 also present, an explosion hazard.  Ultrasonic spraying, for example, is
 considered as  an excellent means f^or this method.  This has the additional
 advantage  that the flux that is  sprayed is always exactly of the "as-
 delivered" composition and no maintenance is required.

       Fluxer materials must be compatible with the flux being used.  In
 Europe,  the traditional fluxer material is stainless steel.  This has proved
 to be inadequate for use with some water-soluble fluxes, which can attack it,
 especially along, the welds, over a period of time.  Early US fluxers were
.frequently made from fabricated  PVC sheet.  This material resists most fluxes


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHES1VES REPORT *
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 very well,.with the exception of those containing esters in their solvent
 system.   Perhaps polypropylene,  which is also cheap and easy to fabricate,
 presents  the best compromise.

       The machine should be fitted with an air-knife immediately after the
 fluxer.   This serves three purposes:

       •      it removes  excess  flux and pushes it back into the flux reservoir
             or a catch  tank
       •      it ensures  a more  even flux distribution
       •      it helps flash off the excess solvents, easing the load on the
             preheater.

       Preheating is the next critical point.   Some European machines are
 inadequate in their preheat temperatures.   The preheating is often thought of
 as  simply to evaporate  the solvents in the flux,  although this is not true.
 It  has to bring all the parts  of the  board and components to be soldered to  a
 temperature  at which the flux  can reduce any  oxides present before contacting
 the wave,  so that the molten metal can immediately start forming intermetallic
 compounds.   This temperature may depend on the flux type and the nature and
 quantity  of  the activators.  As  .an approximate rule,  this critical preheat
 temperature  is generally in the  range of 90°C to 115°C.   As it is expected
 that the  solder should  rise in plated-through holes,  this should be measured
 on  the top side of the  assembly  being soldered at the instant immediately
 before entering the wave.   Temperature  profile recorders are."ideal for
 determining  this.   These are small devices with a number of thermocouples on
 flying leads attached at appropriate  points to the assembly.   The whole device
 is  passed through the machine  and afterwards  the results, held in memory, are
 analysed  and printed out.   There are  excellent devices  of this nature
 manufactured in Europe  and the USA.

       The  method of preheating employed is often unique  to particular
 machines,  ranging from  convected air  to forced hot air  and from low-
 temperature  hot plates  to  electric light bulbs,  or combinations thereof.
 There  is  no  ideal method,  provided that the required'temperature can be
 achieved  in  the minute  or  so of  preheating.   However, particularly when using
 Low-Solids fluxes the infra-red  absorption characteristics of an assembly can
 vary widely  according to the peak wavelength  of an infra-red generator.   Metal
 is  heated  much less efficiently  as the  wavelength increases so,  if the desired
 temperature  is reached  on  the  top side  of the circuit from a very brightly
 incandescent source,  there is  a  very  real risk that the  substrate will become
 too hot,  causing discoloration,  chemical decomposition  or an unusual 'set' due
 to  the glass transition' temperature (T  ) being exceeded  for too  long a time.
 Experience has shown that  the  most usual method employing metallic (Inconel)
 Infra-red heaters  at temperatures within the  range of 400°C to 700°C in a
 polished reflector  or some hot air types give the best  results.

       Energy consumption is  also a factor where,  ideally,  all  the heat
 generated  should be converted  into a  rise of  temperature of the PCB.  More
 important  than the  actual  conversion  efficiency is the  conservation of energy
 in  stand-by  periods.  With incandescent and hot-air preheaters,  they can be
 switched on  as and  when needed and switched off when there are no boards being
 processed.   With metallic  or ceramic  infra-red heaters,  these  should be as
 thin as possible to minimise thermal  inertia.   They can  then be switched on
.for  all the  time there  is  a  board present as  from the entry of the machine (to


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ensure they are at full working  temperature by  the  time  the  board reaches  the
preheat zone) and switched  off again  a  few seconds  before  the  last board quits
the preheat zone.  To .achieve this ultimate performance, sophisticated
temperature controllers using proportional techniques with differentiation and
integration are required, with a sensor wire  in the heater itself.   These
apply full power to  the heater during warm-up to  reach the working temperature
very rapidly.  About 5°C before  reaching  the  preset heater temperature, the
power is progressively diminished until it reaches  optimum at  which
temperature the whole system is  in perfect equilibrium with  no overshoot.   The
moment the temperature varies from optimum, the power is adjusted accordingly
to reestablish the perfect  conditions.  The controller can even anticipate in
advance the conditions needed to perfect  the  temperature control without any
overshoot or excessive damping.

      As well.as "No-Clean" fluxes, low VOC -fluxes  are particularly critical
in terms of preheating.  They usually .contain a considerable percentage of
water which requires much more energy to  evaporate  before  the  board can be
brought.up to the full preheat temperature.

      The design of  the wave is  also  particular to  many manufacturers  and
should be of little  consequence  in the  final  results.

      One exception  to this is that of  double waves. , -This technique is
designed to ease soldering  of "glue-spotted"  surface mount devices.  It
consists of having two separate  waves or  a single ,wave divided into'two zones.
The first wave is purposely highly turbulent, designed to  project the  molten
solder into the shadows created  by the  components,  allowing  initial wetting in
these zones.  The second wave is smooth and is  designed to ensure that the
wetted areas form a bright, even and  smooth meniscus.  There is  a hie  with
this technique.  For it to  be successful, there must be sufficient  flux
available to reduce oxidation at the  second wave.   With conventional fluxes,
this is no problem.  With Low-Solids  "No-Clean" fluxes, there  is sometimes
insufficient flux remaining after the passage over  the first wave to ensure
correct smoothing in the second  wave.   This implies 'that,  at least, medium
solids (about 8-10 percent) fluxes should be  used although some  engineering
changes ma}' help considerably with lower  solids materials.   This is not always
compatible with all  the "No-Clean" criteria.

      Because soldering with modern fluxes is often more critical,  with
narrower operating windows, than with conventional  fluxes, everything .should
be done to ensure ease of soldering.  This means  tightening  of operating
tolerances.   In previous operations,  solder alloys  with tin  contents as low as
40% were successfully used.  Only binary  or ternary eutectic alloys, such  as
63%Sn/37%Pb or 62%Sn/36%Pb'/2%Ag  should  be considered with  Low-Solids "No-
Clean" fluxes.  The soldering temperature is  also more critical  with these
fluxes and should be chosen within the  range  230°C  to 250°C  after practical
trials.                                   _    •  "                   .

      'Optimisation of the soldering process is  tricky, as  there  are many input.
and output parameters.  Some form of  scientific evaluation is  usually
necessary, especially with  "No-Clean" techniques, to bring the trial
procedures within reasonable bounds.  One of  the  easiest ways  of doing this i.s
with the Taguchi method whereby  eight input variables and  any  number of output
variables can be analysed with only twelve experiments,  followed by a
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 thirteenth  confirmatory  experiment after the analysis.   For example,  the input
 variables could be:

       1      Percent  flux solids  (2-6%)
       2      Flux wet weight:area ratio  (0.3-0.7  g.dnf2)
       3      Conveyor speed  (0.9-1.5 m.min"1)
       4      Preheat  air  temperature (180<>C-2200C)
       5      Radiant  heater  temperature  (400°C-500°C).
       6      Solder temperature  (230°C-250«C)
       7      Solder resist (dry  film or  wet film)
       8      PCB metal  treatment  (HAL or IRR)

 The output  variables could  be:

       1      Defective  solder joints
       2      Bridges  between joints
       3      Other bridging
       4      Insufficient rise in PTHs
       5      Skipped  pads
       6      Aesthetically unacceptable  or uninspectable joints
       7      Solder webbing
       8      Visible  residues
       9      Residues causing AT  probe problems
       10     Surface  insulation  resistance etc.
       11     Number of  less-than-minimal menisci
       12     Number of  more-than-maximal menisci

 Each of these output variables  can be weighted  in  terms of their individual
 importance  or the list lengthened or shortened  at  will,  without changing the
 number of experiments, inasmuch  as boards evaluated for one criterion are
 suitable for evaluating  all the  o'ther criteria.

     .  Commercial software is available  for helping in.Taguchi optimisation.

       2.6.2  Controlled atmosphere wave  soldering machines

       These  are essentially the  same as the machines discussed in section
 2.6.1  (q.v.)                                           .                        •

       In reality, only inert gas  is used in commercial  systems,  the gas being
 generally nitrogen.  Reactive gases have been tried, as  well as mixtures of
 inert  and reducing gases.   Soft  soldering .does not reach temperatures where
 reducing gases, such as  hydrogen,  are really effective.   For this reason the
 reactive gas technique is not common.

      There  are three  basic techniques  used to  ensure  the  soldering zone is
 inerted:

      •      a tunnel adaptation  of conventional machines         ,  ' •
      •      purpose-built tunnel  machines
      •      purpose-built hermetic machines.

      The first is cheap  to install and reasonably effective.   However,  it is
more difficult to. ensure  the complete purging of air around the soldering and
preheating zones, an essential element  of the technique.   Practical tests
                                                               \

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 indicate that best results are obtained when the oxygen content is reduced to
 6-10 ppm,  but satisfactory results have been obtained at higher levels of
 oxygen.   To achieve this under these conditions is very difficult and requires
 heavy nitrogen consumption, making it an expensive option in terms of
 operating costs.

       Purpose built tunnel machines use clever gas.curtaining and other
 techniques to reduce the admixture of air into the soldering and preheating
 zones without excessive gas consumption.  Notwithstanding, the consumption
 still remains quite high.

       Purpose-built hermetic machines avoid any risk of contamination of the
 .nitrogen by air.  The assemblies, being processed pass through airlocks at each
 end of the machine.  The air in them is evacuated twice and replaced by
 nitrogen before they are opened to the interior of the machine.   This is much
 more economical to run, but slightly higher in capital costs.

       These machines are typically designed around the use of special fluxes,
 sometimes commercially named preparation fluids.   Early Inert-atmosphere
 fluxes were simply dilute solutions of adipic acid in isopropanol.  New Inert-
 atmosphere fluxes are appearing on the market which are claimed to have more
 benign and/or lesser quantities of residues.  One is claimed to leave even a
 completely inert polymeric coating over both surfaces, giving additional
 protection.  When the quantity of residues diminishes, the metal .salts
 produced by reaction between the flux activators  and oxides present on the
 components are more exposed to the effect of atmospheric conditions in
 service.  Their effect on the reliability of the  assembly is still
 undetermined.

       Some inert-atmosphere machines provide the  option of injecting a formic
 acid mist in the soldering zone, which may be dangerous.  Theoretically,
 formic acid volatilises at about the same temperature as water and decomposes
 into carbon monoxide (the reducing agent) and water at soldering temperature.
 For it to be innocuous, it.would be necessary to  ensure complete removal of
 the acid from, the assembly.  This implies that the whole assembly would need
 to be taken to soldering temperature, including the upper surface of the
 components, to ensure that any formic.acid was totally, decomposed and that all
 parts of it remained at over 100°C during the whole sojourn in the soldering
 zone to  prevent formic acid from condensing back  onto it.   Neither of these
 conditions can be guaranteed and independent tests with and without formic
 acid injection have shown that the residual ionic contamination may be up to
 three to four times higher with the .injection than without it.

       Various contradictory statements have been  published as to whether
 Inert-atmosphere soldering is economically viable, compared with traditional
 wave soldering.   This is not surprising, as individual conditions are so
 variable.   Unless a machine is used to near-full  production capacity,
.preferably 24 hours per day,  then it is possible  that the cost of amortisation
 and keeping it idling (nitrogen consumption) may  become prohibitive.   The
 savings  due to lower dross formation are often very small and are offset by
 the nitrogen consumption necessary to achieve it.  A recent communication even
 suggests that hidden costs involved in inert-atmosphere "No-Clean" soldering
 may actually make it uneconomical.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      Inert-atmosphere wave soldering has  a very narrow  operating window  and
is very difficult to master during  initial set-up.   It may  require  the  use  of
selected solderable components.  Once the  process has been  optimised, the
retouch rate should not be much higher  than that from other processes.  The
switch from a traditional machine to an inert-atmosphere machine can be a
lengthy process.  An overlap period with both machines in service in parallel
of at least 4-8 weeks is generally  necessary.  Again, Taguchi  optimisation  can
be a quick and reliable help to putting such a machine into service.

      2.6.3 Vapour phase reflow

      Vapour phase reflow will not  be discussed due  to the  decrease in  its
use.  This method also results in the emission of "greenhouse"  or other highly
polluting gases including, in some  cases,  ozone-depleting blanket gases.

      There are no known applications whereby some other means  of reflow  would
not give equal or better results, usually  at lower cost.  One  critical
application is for reflowing components on certain complex  flexible circuits.
The non-directionality of vapour phase  reflowing made it technically
attractive for this.  Careful jig design is usually  sufficient  to allow hot
air or infra-red reflow to be equally successful.

      The Solvents, Coatings and Adhesives Technical Options Committee-  does
not recommend vapour phase reflow in the electronics industry,  under the  terms
of Multilateral Funding-.

      2.6.4 Infra-red reflow machines

      There is a wide choice of machines available,  from simple "simmerstated"
Infra-red heaters over a moving conveyor to very complex multi-zone machines
with individual inert gas purging of each  zone, mixed heating methods and .
sophisticated process control.  It  is therefore impossible  in a few brief
paragraphs to give more than an outline of the process.

      The most common process is to stencil or screen solder paste onto the
PCB to be processed, force the components  onto the wet paste and then reflow
the paste to achieve good soldered  joints.

      The paste itself is (usually) an  intimate and  fairly  homogeneous  mixture
of minute spheroids of solder, alloy in  a chemical mixture.  The spheroids are
carefully size-graded and the most  popular grades approximate around 50 ^m
diameter.   Special purpose pastes may have smaller or larger particles.   It is
important to note that smaller particles would appear to approach the ideal,
but they do have more surface area  per  unit weight of metal, hence any
oxidation becomes greater in proportion to the metal mass and the paste
becomes more difficult to use with  a shorter lifetime.  The metal to chemical
ratio is typically in the•range of  85-95 percent of  the  total weight, but the
ratio is about only 50 percent by volume.  It is important  to realise this, as
the quantity of chemicals is much greater with reflow than  with wave or hand
soldering (solder wire usually contains only 1-3% flux by weight) and the
9  All.vapour phase reflow processes emit PFC vapours. These may be the
subject in the future to restrictive legislation designed  to curtail  emissions
of "global warming gases" which may be a cause of climate  change.  .

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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quantity  to  remove  thereafter  is  also  much greater.   The  chemicals  themselves
are a  small  quantity  of flux and,  proportionally,  much larger quantities of
thixotropic  gels  and  other  rheological agents,  heavy molecular weight solvents
etc.   This mixture  of chemicals  is very complex and  the role  that each
component plays during screening/stencilling, holding,  component  placement,
holding again, preheating,  reflowing,  holding a third time  and cleaning (if
done)  must be studied during the  formulation.   The ideal  paste would be a
completely inert  mixture  that  could be screened perfectly without any slump,
with an indefinite  open time on  the screen, have an  indefinite hold time,
would  cause  instant and perfect  adhesion of placed components,  could be held
indefinitely without  humidity  absorption,  could be preheated  and  reflowed
without fault over  a  wide range  of temperature  profiles,  wetting  oxidised
components,  and maintaining perfect adhesion of them during the. process,  and
then leave no chemical residues  or solder  balls whatsoever.   This fiction does
illustrate that the preheat/reflow process is only a small  part of  the total
process and  cannot be taken in isolation.

       The main problem with Infra.-red  reflow of pastes  that are destined to be
cleaned is the importance of ensuring  a perfectly  controlled  thermal reflow
profile.  A  recorder  of the type mentioned under wave-soldering machines  is a
certain asset in  ensuring this.  The various components of  the  chemicals  used
inter-react  with  each other as well as  with what it  contacts  on the  components
and boards.  The  result is  a mixture whose composition  is difficult  to
determine.   Even  a slight change of fusion temperature  and/or time  may render
the.residues totally  impossible to be  removed.   This  is more  important with
pastes that  leave thick deposits,  such  as  common,  general-purpose RMA and  RA
pastes.  Careful  control of the fusion process  is  therefore very  important
when ref lowing this kind of paste.,  and sophisticated equipment  must  be used.

      Modern "No-Clean" pastes rely on  the volatility of  their  major
components at fusing  temperature to minimise the quantity of  visible residues.
It is  important that  at least  a thin film  of flvix  remains until the  solder
solidifies,  to ensure  acceptable menisci.   Some  require the use of  a
controlled atmosphere,  either  ine.rt or  active.   For  best  results,
manufacturer's recommendations should  always be  closely followed.

      As the major part of  "No-Clean"  pastes does  volatilise,  the user should
be aware that a large  facility could emit  significant quantities  of  VOCs
unless precautions are  taken to capture  them.   This  is not  commonly  realised
and many plants violate VOC emissions  laws.  The same holds true  for some wave
soldering 'fluxes,  even  low-VOC types, but  the quantities  of activators  which
evaporate involved are  relatively  small.   The term "low-VOC"  means  that most
of the solvents have  been replaced with  water and  does not .refer  to  the
activators which are  always VOCs at soldering temperature.  With  pastes, up to
90% of the chemicals,  representing typically 45% of  the volume  of the  bought-
in paste,  are. organic  chemicals which,  sooner or later, volatilise  during
processing.

      2.6.5 Other reflow methods

      There are a number of alternative  methods  of reflow used.   These include
thermode,  hot gas or  air, laser, npn-coherent focused flash radiation,  hot
belt (mainly ceramic  substrates),  liquid immersion,,  and the old soldering
iron.   These-will not  be discussed here,  as they are  of limited interest and
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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their advantages and disadvantages related to cleaning  are  logical  extensions
of the previous sections.
2.7   CLEANING MACHINERY

      There are many different types  of  cleaning machinery  and features  within
specific types.  The following summaries  are  therefore  broad and the  user is
warned that they are not comprehensive.   Auxiliary  features,  such as  waste
water treatment, are not considered in these  lists.   The  term "drag-through"
is used here to describe liquid that  remains  in a machine from one operation
to the next, as opposed to drag-out which is  liquid that  remains on the  work-
pieces from one operation to the next.

      2.7.1 "Dishwasher" types

      "Dishwasher" types of batch machinery are available for use with some
solvents (including some HCS solvents),  some  emulsion cleaning and most- forms
of aqueous cleaning.  It is important to  note that  unmodified domestic or
industrial dishwashers are unsuitable for cleaning  electronics assemblies for
many reasons.
Advantages
      •     Low capital cost
      •     Small floor space  "footprint"
      •     Cleaning quality may be  excellent
      •     Some may be purged for flammable/combustible  solvents

Disadvantages

      •     High energy and pure water  requirements  per unit  area
      •     Very low throughput capacity  (typically  1  nr.h"1)
      •     Drying quality may not be perfect
      •     Optimisation of wash and rinse  cycles  difficult
      •     Machine drag-through high
      •     Saponification may be difficult
      •     Handling of heavy  baskets at  a  low  level

      2.7.2 "High-Throughput:"'  types

      "High-Throughput" types  of batch  machinery are available  for use with
some solvents (including some  HCS solvents), some  emulsion cleaning and most
forms of aqueous cleaning.  They are characterised by  separate  machines or
compartments for cleaning and  drying, separate  optimised  wash and  rins.e
circuits for cleaning and rotary high-speed hot-air  knives for  drying.
Advantages
            Will accept output of most  soldering  machines  (20  m2.h"1)
            Very efficient cleaning
            Very efficient drying
            Low pure water and energy requirements
            Moderate capital cost
            Simple to automatise
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       •     No  lifting of heavy baskets
       •     Virtually no machine drag-through

Disadvantages                        -    .

       •     Unless  automated,  requires  some manpower
       •     "Footprint" relatively large (up to 6 m2)
       •     Peak  power consumption high (average low)
       •     Combustible solvents need module with different concept
       •     Flammable solvents excluded

       2.7.3 "Tank-line" batch  types

       "Tank-line" types of batch machinery, are  available for use with some
solvents,  (including  some HCS  solvents),  some emulsion cleaning and most forms
of aqueous cleaning.   They are characterised by separate tanks,  usually
agitated  immersion, for each operation,  in line.   The  baskets are usually
handled by automatic  transfer  mechanisms ("hoists")  which are designed to •
perform both the  lifting and linear movements.
Advantages
      •      Some will  accept  output  of  soldering machine  (5-15  m2^"1)
      •      Low pure water  requirements          .                  ~ • '
      •      Simple  to  automatise
      •      No lifting of heavy baskets
      •      Virtually  no machine  drag-through
      •    '  Highly  flexible modular  conception             .                   .
      •      Combustible solvent-compatible

Disadvantages

      •      Unless  automated,  requires  some  manpower
             "Footprint" large  (up to 12 m2)       '-.'••
      •      Cleaning not always as good as may be required
      •      Drying  not always  as  good as may be required
      •      Energy  consumption may be high                        -
      •      High capital cost
      •      Flammable  solvents excluded

      2.7.4  Totally enclosed  types.

      Totally enclosed' types  of batch machinery are available for use with all
solvents, emulsion  cleaning and all  forms of aqueous  cleaning.   They are
characterised by a  sealed cleaning chamber and tanks  containing the  various
liquids which;.can be pumped in and out  the chamber.
Advantages
            Lends itself  to rotary  agitation
            Lends itself  centrifugal  drying
            Good cleaning quality possible
            Good drying quality possible
            Small footprint possible
            Excellent flexibility
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       •      Vacuum drying after centrifugation
       •      Easy inert atmosphere purging
       •      Combustible/flammable solvent-compatible

 Disadvantages

       •      Assembly size and weight may be limited  .
       «      Very small throughput (typ.  1-2 m2.h"1)
       •      High capital  cost
       •      Long cycle times
      ••      High machine  drag-through
                                                    /
       2.7.5  Conveyorised  "in-line"  machines

       Conveyorised "in-line"  types  of machinery are available for use with all
 solvents,  emulsion cleaning and all forms of aqueous cleaning.   They are
 characterised by the form of  a tunnel divided into compartments for each
 function and through which an open  mesh  conveyor belt transports the
 assemblies for  cleaning.   Warni'ng:  there are some smaller Conveyorised
 machines available which  do not comply with all the criteria listed below and
 which  are  often inefficient in terms of  cleaning and/or drying quality.
Advantages
             Can be matched  to  any  machine(s)  for throughput capacity
             Virtually  no  manual  production operations
             Modular  types flexible
             Easy handling of combustible  solvents
             Inert gas  purging  possible  for flammable solvents
Disadvantages
            High  to very high  capital  cost
            Large to very  large  footprint
            High production  rates  impose very  long  machines' (>15  m)
            High energy and  pure solvent water demands
            Generally poorer cleaning  quality  than  batch  machines10
            Generally poorer, drying  quality  than some batch machines10
            High drag-out  on horizontal assemblies
            Angle of spray attack  usually less than ideal
10   These generalisations should be qualified by the statement that a few,
costly, state-of-the-art machines may give  excellent cleaning  and drying
results. They are based on the fact that  if a  conveyor moves at  1.5 m.min"1
and a cleaning, rinsing or drying phase of  the process requires,  say,  2-3
minutes to achieve good results, the compartment for that  phase  should be 3-
4.5 m long and be equipped with the appropriate treatment  for  the whole of
that length. Few machines offer this possibility.  Slowing  down the conveyor
may dramatically improve this situation but at the cost  of perhaps not being
able to use the other machinery to full capacity.

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      2.7.6 Vapour phase  solvent machines

      These can be used only with  solvents whose boiling  point  is  sufficiently
low so that the parts being cleaned  are  able  to support the  temperature  and
whose vapour is much denser than air.  The components must also be compatible
with the solvents and.their vapours  (please consult  the manufacturers'
literature).  Halocarbon  solvents  were most often used with  this technique.

      As awareness of environmental  problems  increased, such machines became
more sophisticated with features to  reduce emissions.  Nevertheless, few of
the open-top batch machines are able to  reduce emissions  to  acceptable levels
when using CFCs, HCFCs, MFCs or PFCs.  On the other  hand, some  of  the fully
enclosed, entirely automatic ones  may be acceptable.  'Their  use with less
polluting solvents is not so critical but it  is still a wise economical  and
environmental precaution  not to permit any emission  that  is  not strictly
necessary.  For this reason alone, .open-top vapour phase  solvent machines are
undesirable for use with  any solvent used for defluxing or drying  printed
circuit assemblies.

      There is a problem  when using  any  solvent in.vapour phase in conjunction
with PCB assemblies, especially for  tightly packed surface-mounted ones,
regardless of the machine's design.'  Vapour becomes  trapped  under  the
components and, as the'assemblies  are removed from the vapour zone, it takes
considerable time, for the trapped  vapour to,fall back into the  machine, .often
counted over several minutes.  The machine design and programming  must take
this factor into account.
2.8   MACHINE AGITATION

      The efficiency of a cleaning operation is often a critical function of
the method and total energy used  in agitating the solvent with respect to .the
parts being cleaned.  This reaches a peak when cleaning under large surface-
mount devices with small stand-offs from the printed circuit.  This section
gives a brief discussion of the most usual types encountered.

      2.8.1 Sprays for cleaning

      Spray cleaning, correctly applied, is the most efficient way to remove
soils.  The function is to ensure a maximum high-energy penetration of the
fluid into all the crevices, over the required time.  Many cleaning processes
may require several minutes to. ensure dissolution of the soils, even with
high-energy spraying.             .

      The form of the sprays should be solid,, coherent jets or linear curtains
applied to the parts at an acute  angle.  This angle should be as small as
possible to ensure minimum loss of kinetic energy by the fluid "puddling" on
the substrate, but should not be  so small that severe shadowing occurs.
Empirical tests reveal that the best compromise, depending on the machine
design, is usually 15° to 45° with respect to the substrate surface.  Batch
machines-are generally better than conveyorised machines in this respect. • The
geometry of the spraying should be such that all parts of the board are
subjected to direct jet action at least over a part of the cleaning cycle.
This implies that there should generally be relative movement between the
nozzles and the assembly in both  axes.


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      The efficiency of spray cleaning  is dependent on  the kinetic  energy with
which the cleaning fluid  is sprayed onto the  assembly.  This  is  a function  of
the spray pressure, the spray volume, the fluid velocity, the nozzle  design,
the distance between the  nozzles and  the assembly  and some minor factors.   It
is perhaps important to note that a given energy may be imparted equally by a
high pressure, low volume or by a low pressure, high volume flow, but the
nozzle design would be different in each case.  The energy is given by the
pump and if a pump consumes a given power at  the same efficiency, the results
will be similar, no matter what the pressure  and volume,  assuming correct jet
design.  As a rule of thumb, for reasonably efficient cleaning of electronics
assemblies, the minimum practical energy level of  a jet bar is approximately
represented by 2 kW (2HP) of pump motor consumption per total metre length  of
bar.
                                                              v

      The high energy levels produced by efficient spray  cleaning are
partially dissipated when the jets or curtains hit the  assemblies.  As a rule,
the higher -the velocity,  the more is  the energy lost by the rebounding of the
solvent from the topography of a typical assembly.  This  often produces a fine
mist.  Even with combustible liquids  with a flash  point of 100°C or more, this
mist can be easily ignitable and, if  the proportions are  right,  even
explosive.   It is therefore essential to correctly inert-gas  purge  any
machines where spraying of flammable  or combustible fluids occurs and to use
flame-proof and/or inherently safe.electrics  and electronics  in  appropriate
premises.

     • The removal of~HCS  solvents by  water is a cleaning  operation  and not  a
rinsing one: it must be followed by a rinsing operation.

      2.8.2 Sprays for rinsing

      The whole function  of rinsing is different from cleaning and  efficient
rinsing is best achieved by low-energy spraying.   It should be remembered that
at least the last rinse or rinses should be done with pure uncontaminated
solvent or water, so the volume consumed should also be minimised.  The
function of rinsing is to replace the contaminated solvent or water by
successive amounts of a cleaner product of the ,same nature.   In  other words,
it is a series of successive dilutions until  the residual contamination level
is acceptable.

      The best spray form is a coarse mist with a  mean  droplet size smaller
than the smallest interstice, so that there is direct penetration with
displacement of the contaminated fluid before much mixing occurs.   It is
therefore inefficient to use energy levels which are too high.   A typical pump
energy level for_good operation is 200-500 W.m"1  of spray  bar  and the  nozzle
design should be such that the spray,  velocity is low with a droplet size of
typically 20-100 ^m.   This may be achieved most efficiently with pressures  of
about 3 bars.

      Again,  the angle of attack should be acute at the moment of impact.
This may imply almost horizontal nozzles on conveyorised machines,  if the
velocity is fairly low,  as recommended above.  Batch machines, with the
assemblies  held in baskets in a near-vertical position, offer the best and
most economical rinse conditions, but the nozzle design may require to be
different for the top and bottom spray bars,  due to the effect of gravity.
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       Machines which use the same spray bars for cleaning and rinsing are
 essentially a compromise in that neither operation can be done under optimum
 conditions.   This may be partially compensated for by adjusting the cleaning
 and rinsing times and the number of rinses.   One severe disadvantage of such
 machines is the "drag-through" caused by contaminated liquid from the previous
 operation remaining in the pipe-work,  so that clean rinse liquid is
 contaminated even before it reaches the assemblies being cleaned.   This can
 severely compromise the throughput and liquid consumption of such machines by
 increasing the number of rinses before adequate cleaning quality is achieved.

       2.8.3 "Under-surface" spraying

       "Under-surface" spraying is not newj  but it has regained popularity as a
 means  of mechanically agitating combustible  solvents without forming an
 ignitable'mist.   It consists of high-energy  jet spraying of the parts being
 cleaned with the said parts actually immersed in the liquid.   The
 hydrodynamics of the'spraying is complex 'and the kinetic energy loss is high
 over relatively short .distances.   As the boards are usually held vertically in
.a  basket or jig (batch machine's)  or at a 30°-45° angle on conveyorised
 machines,  the jets are most frequently applied edge-on or close thereto.   To
 calculate the required pump size,  count on  at least 5 HP for each  square metre
 of area being agitated,  plus an.extra 10% for each 10 cm of the distance over
 which  the jets should remain effective (rule of thumb).   In this -case,  in
 order  to keep the jets as coherent as  possible over a distance,  it is
 essential that the pressure be,high (>20- bars) and the volume low.

       The high kinetic energy is dissipated  thermally within the solvent.   It
 is.possible  that the temperature rise  may reach bounds where it approaches the
 fluid  flash  point.   In this case,  water cooling will be necessary.   The
 working temperature should always  be maintained at 20°C under the  flash point
 with additional  safety devices to  shut the machine -down completely 'at 15°C
 under  the flash  point.

       There  is no advantage to using this technique over 'conventional spraying
 with non-flammable substances and its  poor  energy efficiency is marked.

       2.8.4  Ultrasonic agitation

       The use of ultrasonics on electronics  assemblies is the least  understood
 and  most controversial cleaning technology.

       •The  main classes' of components reported as being potentially damaged by
 ultrasonic  agitation are non-moulded semiconductors (metal,  glass  and ceramic
 cases),  thermionic devices,  large  multilayer ceramic chip capacitors,  liquid
 crystal  displays and components wound with unencapsulated fine wires.   This
 list is  probably not exhaustive and it certainly does not mean that  all
 components  of the mentioned types  will fail  after ultrasonic cleaning.   It
 means  that  particular prudence is  required when judging whether assemblies
 with any of  these components on may be cleaned or hot.

       Most  experience with ultrasonic  cleaning was with CFC-113.   It is of
 first  importance to note that data obtained  with one solvent type  should never
 be  considered as necessarily valid with a different solvent type.   The
 compressibility  and cavitational characteristics of any liquid is  unique to
 that-liquid  alone..


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      The first essential  criterion  to  effective  ultrasonic  cleaning is for
cavitation to occur on  the  surface to be  cleaned.   This  condition can be
achieved only if there  are  no  dissolved gases  and no  particles  between the
transducers and the parts,  otherwise all  the ultrasonic  energy  will  be
dissipated away from the cleaning zone, where  it  will serve  no  useful purpose.
To achieve adequate cavitation in water or  aqueous solutions, for example,
they must be degassed two  or three times  a  day and continually  filtered down
to 1 fzm particle size.  Degassing is usually done by  subjecting the  solution
under mechanical agitation  to.  a moderately  high vacuum (<1 mb)  at 30-50°C.
Some organic solvents can never be degassed sufficiently to  achieve  good
cavitation.  The quality of emulsions can also vary by the application of
ultrasound.

      Frequency is another  cause of  misunderstanding.   Ultrasonic energy is
created by the instantaneous implosion  of cavities and the consequent
adiabatic compression of vapour therein.  This .causes an astronomic  rise of
temperature to thousands of degrees  over  an extremely short  time,  measured in
nanoseconds, in turn causing a mechanical shock wave  to  form in the  virtually
incompressible fluid.   This shock wave  does the work.   It is typically
amortised within a millimetre  of the point  of  cavitation, hence the  importance
of cavitation on the part being cleaned,  preferably on' the contaminant itself.
Cavities do not form at the frequency of  the ultrasonic  energy  but build up
slowly over tens or even hundreds of cycles.   This slow  rise is a means of
storing energy which is released at  the instant of implosion.   The high-energy
shock wave is therefore completely aperiodic and  cannot  be the  cause of a
sustained resonance.  On the other hand,  if there are undamped  or poorly
damped mechanically resonant parts,  such  as-unsupported  wires or quartz
crystals, these may be  set  to  oscillate instantaneously  at their own natural
frequency, no matter what  this is.   Repeated oscillation may cause,  in the
long term, fatigue which could lead  to  a  loss  of  reliability.   For the
ultrasonic energy to cause  direct damage  by resonance to a part would seem
highly improbable.  The following conditions would have  to be united:

      •     the resonant part  would  have  to- have  a natural frequency exactly
            equal to the excitation  frequency
      •     the resonant part .would  have  to have  a high  Q to obtain  sufficient
            amplitude to cause fatigue
      •     the excitation  frequency would  have to be stable, which  is rarely
            the case
      •     the excitation  would have to  be unmodulated  to maintain  continuous
            oscillation, which is rarely  the case
      •     the direction of excitation would  have to be such that the
            amplitude of oscillation was  maximised.

It is unlikely that all these  conditions  would apply.  Frequency seems,
therefore, not to play  a direct role.   On the  other hand, it' can play an
indirect role in"that lower frequencies may produce larger but  fewer cavities,
so-that the implosion energy per cavity may be greater.   Some systems use
sweeping frequencies.   Over narrow bands  (up to one octave),  this  technique
would not bring about any significant difference.   Another new  technique,
developed in Japan, is  to use  simultaneously three frequencies,  such as 35
kHz,  70 kHz and 200 kHz.  It is claimed that this  is  particularly effective,
with correct dosing of  each of the three  amplitudes,  when using degassed water
or aqueous solutions.
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      No matter what  system  is  employed,  successful  use  of  ultrasonic, cleaning
depends on:                .                                 .

      •     cavitation  occurring  in  close proximity  to the  contaminants
      •     cavitation  of  sufficient .amplitude/frequency characteristics  to
            ensure adequate  acceleration  of  the  cleaning process
      •     thoroughly  degassed solvents  or  solutions
      •     very  tight  process  control
      •     provably, no deterioration  of components
      •     provably, a significant  improvement  in the residual contamination
            levels

If any one of  these criteria cannot  be  met,  ultrasonic cleaning should not be
used.  In the  last condition, "significant"  means that if the  levels  are  not
at least 30-50% lower than without ultrasonic cleaning,  under  otherwise
identical conditions, then the  process  is not optimised.


2.9   DRYING        '  •

      Drying is an important part of the  cleaning process and  can  contribute
to the overall success  or  otherwise  of  the operation.  The  most common methods
of drying organic solvents and  wa'ter fall into three categories, mechanical
drying, evaporative drying and  vapour phase  drying.  Each of these has a
number of sub-categories.

      Whether an  organic solvent  or  water (or a  mixture  in  some cases) is used
as the final rinse,, it  must  be  realised that drying  does  involve thermal
considerations by all three  categories  enumerated above.

      2.9.1 Mechanical  drying

      The two main subcategories  of  mechanical drying are' effective air-
knifing and centrifugation.   In both cases,  they are accompanied,  to  a certain
extent, by a small proportion 'of  evaporation.  This  absorbs sufficient heat
from the ambience to provide the.  required latent heat of evaporation.  The
result is a drop  in temperature.  With  some  organic  solvents,  this may be
sufficient under  some conditions  to  .take  it  below the dew point, causing
condensation'Of atmospheric  humidity onto the assemblies'and subsequent
further difficulties.   The latent heat  of condensation of this water  will
supply some of the heat required  to  evaporate the solvent and  an equilibrium
will be reached (assuming  the solvent is  not water soluble).   It is sufficient
to ensure that the air  in  the knife  or  in the centrifuge, along with  the
assemblies,  is a  few degrees higher  than  the ambient temperature to avoid
this.  In any case, the compression  of  the air in the air-.knife system should
be sufficient to  ensure an adequate  heat  input.

      Mechanical  drying is,  by  far,  the most effective means of gross drying.
Ninety.to ninety-five percent of  residual water  can  be eliminated  from even
tightly packed surface-mounted  assemblies in a matter of thirty seconds.  This
will require less than  10  percent of the  energy  needed to evaporate an
equivalent mass of water.  High-boiling point solvents,  e.g. diglycol ethers_
with boiling points in  excess of  200°C, are  much more recalcitrant to
mechanical removal.  This  is because their evaporation rate is insignificant
below 100°C but,  above  all,  they  wet the  substrate and components  better  in


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 the  interstices, making  them  more  difficult  to  shift.   In some recorded
 experiments using hot  air-knives at  80°C,  on circuits  with a medium-high   •
 density of SM components, water was  retained at an average of 4.2  g.dm"2 after
 immersion in water  followed by ordinary handling.   Dipping into a  solvent  with
 a boiling point of  210°C, the average weight of retained solvent was  3.9 g.dm"
 2.   After 20 seconds air-knifing at'  80°C,  the figures.were  respectively 0.5
 and  1.8 g.dm"2.   After five minutes,  the residues were <0.01  (the limit  of
 measurement, approximating to total  dryness)  and 0.55  g.dm"2  respectively.
 Even after 30 minutes, the solvent-wetted  boards were  not dry,  even with, the
 combination of high-velocity  air and moderately high temperature.   Repeating
 the  experiment with water to  which 5% of isopropanol was added changed the
 mean zero and 20 second  weights to 4.05 and  0.35 g.dm"2  respectively,  a
 distinct improvement over, water alone.  (These  figures were derived from
 experiments conducted  in 1993 by a Swiss company which requested anonymity.)

      The supreme advantage of mechanical  drying is that most of the  water or
 solvent is eliminated  in discrete  droplets,  typically  100 /jm -  1 mm diameter.
 As seen earlier, rinsing is a process of successive dilutions.   There dre
 therefore always some  contaminants in the  residual  liquid and these are
 eliminated along with  the droplets.  This  method therefore  produces a
 significant improvement  of cleaning  quality  over other methods  of  drying.

      There is no evidence of an increase  of fire  risk when hot-air knifing
 combustible solvents.  The droplet size is large and the air velocity is high,
 so that the concentration cannot reach dangerous levels,  provided  that the air
 temperature is kept well below the flash point  (at'least 20°C less).

      It may perhaps be  useful to  define air-knifing in this context  as some
 machine manufacturers  mistakenly call forced-air circulation air-knifing.
 With an air-knife,  there are  two criteria: the  air  is  forced through  a linear
 orifice, usually a  few millimetres wide, and impinges  directly onto the parts
 to be dried.  The air  velocity is  generally  about  50 m.sec"1  or more.    In  in-
 line machines, two  or  three air-knives on  each  side provide the action.

      2.9.2 Evaporative  drying

      This consists of either letting the  residual  liquid evaporate to dryness
 or to force it dry  by  increasing the temperature and/or reducing the  pressure.
 The usual means for this are  heating by convection, forced air,  Infra-red
 radiation in ovens  or  tunnels or vacuum ovens.

      The chief disadvantage  of evaporative  drying  is  that,  as  drying
 progresses,  the volume of liquid diminishes.  The  remaining liquid  tends to
 move to where the capillary spaces are smallest,  as the contaminants  become
 gradually more concentrated in it.   These  spaces are mainly round  the solder
joints.   Eventually, these contaminants will become dry at  the  places where
 they are deposited, often where they can cause  the  most electrical  or- chemical
harm.  It is for this  reason  that  it is stated  above that mechanical  drying is
preferable for the  gross liquid removal.   Evaporative  drying is used  for the
 remaining 5  or 10 percent that mechanical  drying will  not remove.

      One of the important aspects of evaporative drying is the large amount
 of power required to supply the latent heat  of  evaporation  of the  liquid being'
 removed.  In the case  of water, for  example, about  6.5 kWh  is required to  dry
 off each litre of water  at 80°C, assuming  a  10% heat transfer efficiency


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     2-46

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 (typical for a forced air oven, convection ovens being even less efficient).
 This is typically ten times higher than is required for mechanical removal.
 This is another major reason why the latter is preferable for gross drying.
 Vacuum drying does not escape this rule, even though it is achieved faster and
 at a lower temperature.  Any power gained by not heating the solvent to such a
 high temperature to obtain a suitable rate of evaporation is more than
 compensated for by the power consumed by the vacuum pump itself.  The latent
 heat of evaporation remains substantially constant over a wide temperature
 range and this represents the major part of the power requirements.
                x
       Vacuum ovens must be fitted with effective vapour traps to prevent water
 or solvent vapours from entering the pump, causing a deterioration of the
 lubrication and thus damage and to prevent lubricating oil vapours from
 refluxing into the oven,  where it could condense in the oven and onto the
 workpieces.

       Infra-red drying efficiency depends on the absorption characteristics at
 the wavelength of the radiation s.ource.   Black and other dark components tend
 to become hotter than the relatively light ones and the substrate.   This
 temperature differential may become relatively great in some cases.

       Forced air drying is the means for the most uniform heating of wet.
 assemblies.

       2.9.3 Vapour phase drying

       This is the familiar way of drying after solvent cleaning using CFC-113
 or 1,1.1-trichloroethane.   There are three variants, all based on the same
 basic idea.   These are drying off a solvent in its own vapour,  drying off a
 solvent in the vapour of another solvent miscible with it and drying, off a
 solvent with another one which is not directly miscible with it.

       It is important to understand the operating mode of a typical straight
 vapour phase cleaning operation.  The parts to be cleaned are immersed in the
 boiling solvent for gross cleaning.  They are then transferred to a clean,
 cold solvent bath for rinsing.  They should stay there until,  at least,  the
 whole assemblies cool to the solvent temperature.  They are then lifted out of
-the liquid into the solvent vapour.  Solvent condenses on the parts and gives
 a  final rinse of relatively clean solvent.  The latent heat of condensation
 released causes the parts to heat up rapidly and condensation ceases when .they
 reach the same temperature as the vapour itself.  The parts can then be slowly
 withdrawn slowly out of the machine in such a way as to prevent any vapour
 from being drawn out with them.  This technique is not generally recommended •
 for defluxing because there are many substitute processes which are less
 polluting and .give better results.              / .

       It is  also possible to dry miscible solvents and recover the drag-out by
 using vapour phase drying.  This is theoretically possible using any solvent
 which mixes  with the cleaning solvent and satisfies the criteria in the
 previous sections.  This is perhaps amongst the most efficient ways to dry off
 high boiling point solvents (typically BP >170°C and flash point >85°C).   This
 can be done  with many solvent families but with all the disadvantages of
 vapour phase cleaning.  In effect,  the vapour phase solvent cleans off the
 contaminated cleaning solvent.  In recent years, it has been proposed to use
 HFCs and PFCs,• which are greenhouse gases, for this application.  As the


                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      2-47

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 emissions of  the polluting vapour  phase  solvents  are  always  more than finite
 and  there are  other ways  to  achieve  similar  or  better results for electronics
 cleaning and  drying,  it is not  a recommended process.

      The Solvents, Coatings and Adhesive.s Technical , Opt ions Committee does
.not  recommend  vapour  phase drying  of heavier solvents using  HFCs and PFCs in
 the  electronics industry, under the  terms of Multilateral  Funding—.

      The use  of vapour phase drying of  non-miscible  solvents is most commonly
 applied to water.  It is  exactly the same as the  previous  case except that
 there is one  intermediate step  between the cleaning and drying operations.
 This involves  wetting with some form of  third solvent which  is miscible or can
 be made miscible with both the  cleaning  and  drying solvents  or displaces the
 cleaning solvent.  One way of doing  this, with  water  as the  cleaning solvent,
 is.to use an  oxygenated hydrocarbon  solvent  such  as a light,  alcohol or a
 heavier diglycol ether.   This will dissolve  the residual water and the
 resultant mixture  can be  dissolved in the drying  solvent.  Another method is
 to use an intermediate bath  of  the same  solvent as the drying solvent to which
 some surfactant is added:  To'displace, water from,a part,  a  light aromatic
 hydrocarbon may be used,  such as toluene (with  flammability  and toxicity
 problems to be overcome).  Drying  water  using vapour  phase techniques is
 neither useful nor viable for ordinary electronics, assemblies,  although it may
 have applications  for some complex optical parts.   As it is  as polluting as
 the  last process,  it  is equally not  recommended in this context.

      The Solvents, Coatings and Adhesives Technical  Options Committee does
 not  recommend  vapour  phase drying  of water using  HFCs and  PFCs in the
 electronics industry,  under  the terms of Multilateral Funding—.
2.10  CONTAMINATION AND QUALITY CONTROL

      There are three  factors which must be  analysed  to  ensure  sufficient
quality in relation to the job to which the .soldered  and possibly  cleaned
assemblies will be put and to the expected lifetime.   These  include  the
following:

      •     Is the soldering quality  sufficient  that  the rate of retouching is
            small and  that the risk of  breakdowns  due to faulty soldering is
            negligible?                 ~ •
      •     Is there any likelihood of  electrical  failures due  to  the  presence
            of contaminants causing corrosion  or leakage during the  expected
            •lifetime of the assembly  under the expected  worst conditions  of
            service?
11   All vapour phase drying processes emit CFG, HCFC,  HFC or PFC Vapours.
Where these are not already restricted,  they may be the  subject  in the  future
to restrictive legislation designed  to  curtail  emissions  of  "global warming
gases" which may be a cause of climate  change.

12   All vapour phase drying processes emit .CFC, HCFC,  HFC'or PFC vapours.
Where these are not .already restricted,  they may be the  subject  in the  future
to restrictive Legislation designed  to  Curtail  emission's  of  "global warming
gases'" • which may be a cause of climate'change.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     2-48

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       •     Is the total process arranged so  that  the production, quality'can
             be constantly monitored and, if necessary,  corrected and  is  it
             likely to introduce by itself problems which  can upset  later
             quality controls as well as in service?

 The first two of these questions relate directly to . the reliability of the
 product.  The third one is an internal production problem which  is not always
 evident.  One simple example is that if a "No-Clean"'soldering flux with  a
 high level of residues is used, automatic testing may be  upset by contact
 problems.                                                 .

       As a general rule, the third question is answered by a series of
 empirical trials.  These trials are usually on-going until the whole
 production line runs smoothly.  The first two questions are answered by three
 forms of instrumentation.

       2.10.1      Solderability testers

       There are several types of solderability tester available  on the market.
 The. most usual one uses the "wetting balance method".   There are two variants,
 using a solder bath and a globule.   The first-named is most generally useful
 for printed circuit boards and wired components whereas the latter type is
 certainly indicated for surface-mount chip components,  but can also be used on
 some other component types.   Some instruments have interchangeable solder
 sources.  All incoming components, .including .PCBs,  should be tested to ensure
 good solderabil.ity and this is especially important with  "No-Clean" processes
 where operating windows are often so narrow that a small reduction of
 solderability will create catastrophic problems.

       2.10.2 .     Ionic contamination testing

      • Ionic contaminants are those  that are most likely to cause electrical
 problems in an assembly.   With "No-Clean"  processes,  there is a deliberate
 introduction of ionic contaminants  that is hopefully- controlled by the process
 parameters and thus rendered more-or-less  relatively harmless.   Ionic
.contamination testing after such a  soldering process is meaningless.   On the
 other hand,  it is very important to  test incoming components and PCBs with an
 adequate instrument because any contaminants will pass  through the process and
 produce  any one or more of three effects:
       •      they may upset the soldering process
       •      they may up-set the careful balance of the flux residues, causing
             poorer electrical quality and corrosion
       •      they may be the cause of a definitely shorter lifetime of the
             assembly under service conditions.

 This  is  therefore an essential element' of "No-Clean" techniques relating to
 quality.

       Where  cleaning is carried out, testing of incoming components may.be
 often dispensed with because the soldering processes are usually more tolerant
 of .minor  solderability problems and any incoming contaminants should be at
 least partially removed during the cleaning process.
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      2-49

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      When CFC-113 azeotropes were used for cleaning, the process was
relatively "fail-safe".  This meant that inadequate cleaning often resulted  in
a slight drop in quality.  This is not the case with most substitute methods.
Ionic contamination testing is the preferred QC aid to ensure that the quality
is maintained at an acceptable level and is a "must" for most users.  Low-cost
process-control instrumentation is therefore becoming available as well as the
very sophisticated testers, which have been available for many years.

      2.10.3      Surface insulation resistance and electromigration testing.

      SIR testing has been largely ignored as a means of quality control until
recently but is often used as a qualification procedure for methods.  New
variants have contributed to its being adopted as a production test with
accelerated test times of about 8 hours'.  This is aided by the relatively
recent introduction of new automated test instruments -which take the
difficulties out of the practical measurement.

      Such SIR test techniques are an extremely good complement to ionic
contamination testing, but it is emphasised that each gives part of a total
picture with almost no overlap.  On occasion, either may indicate dangerous
conditions of residual contamination that the other could never even detect.

      They are usable after all types of cleaning process and after "No-Clean"
soldering.  They are especially useful after aqueous cleaning methods.


2.. 11  PHOTORESIST DEVELOPMENT

      In the. 1991 Solvents TOC Report (UNEP 1991), a detailed section was
published on the problems of developing dry film resists used for etch,
electroplating and solder masks with 1,1,1-trichloroethane.  This is a niche
application in the printed circuit manufacturing industry.

      Dry film resists were introduced in the late 1960s and they quickly.
found a ready and wide market for some applications.  They were initially all
1,1,1-trichloroethane-developed.  They supplanted wet resists for most PCB
manufacturing applications.  The process caused both considerable OD solvent
emissions, as the solvent was sprayed, and water pollution, as there was
solvent drag-;out into a final water rinse.

      By the mid-1970s, aqueous-developed dry-film resists became available.
These were slow to become popular as the process was initially more difficult
to master and the reject rate was higher.  These early problems were overcome
and,  by 1980, probably over half of the dry film resist .used, of all types,
was aqueous-developed, with an ever-increasing proportion.

      By the mid-1980s, aqueous methods were used for over 90% of etch and
plating mask applications and 75% for solder resist applications.  The
remaining solvent-developed operations were generally, reserved for state-of-
the-art applications, where the fine-line qualities of aqueous methods were
perhaps at the limit of the technique.

      Today, there are substitutes available for 1,1., 1-trichloroethane- .
developed dry-film photoresists for all applications:
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     2-50

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a. Etch and plating resists:
      •     aqueous-developed dry film photoimaging  resists
      •     aromatic solvent-developed wet-film photoimaging  resists
      •     aqueous-developed wet-film photoimaging  resists
      •     fine-line silk-screening UV-curing resists
      •     fine-line silk-screening thermal-curing  resists •

b. Solder resists:   >        •      •

      •     aqueous--dev. dry-film photoimaging (not  universal)
      •     curtain-coated HC-developed wet-film photoimaging
      •     curtain-coated aqueous-developed wet-film photoimaging
      •     screen-coated HC-developed wet-film photoimaging
      •     screen-coated aqueous-developed wet-film photoimaging
      •     fine-line silk-screening UV-curing resists
      •     fine-line silk-screening thermal-curing  resists

      For further details and a more technical discussion on  this matter,
please refer to the 1991 Solvents TOG Report (UNEP,  1991). .

      There is no technical nor economic reason why  1,1,1-trichloroethane-
developed dry-film photoimageable resists of any nature should continue  to be
used:' there is a wide choice of substitutes suitable for all  applications. '
2.12  SUMMARY

      The electronics industry,, which was heavily dependent on ozone-depleting
solvents until recently, is fortunate to have a wide range of substitute
materials and processes available,  there is no technical reason why any
company, large or small, in a developed or developing nation, should not be
able to move away from such solvents immediately.  Economical considerations,
reported in previous editions of  the Solvents TOC Report  (UNEP 1989, 1991),.
have shown that most substitute processes for this industry are'less costly,  to
run and, most often, give improved technical quality.  On the other hand, a
relatively large capital investment is sometimes required to obtain the
required results.  This could be  an obstacle, especially for small.companies
manufacturing "hi-tech" electronics.  However, even with heavy amortisation
costs, most of these processes can be economically and technically viable.

      A number of secondary problems have arisen.  One of the most important
is the fact that most information has been published only in English.  English
is the most common language in the electronics industry, although it may be
poorly understood, especially in  developing nations.  This .is a severe
difficulty which can be overcome  only by close cooperation between English and
non-English speaking experts.  "Hands-on" experience is 'also essential.  It
may be useful to publish a series of simple pamphlets (say, up to'16 pages)  on
single subjects written in English by experienced engineers.  These could be
distributed to developing nations where local engineers could translate them
into the local language.  Then they could be published and distributee! free-
6f-charge throughout the local industry.  The total cost of this could be less
than that of a single mistake in  equipment or process selection.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                     2-51

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      To  substitute  for  CFC-113  in defluxing,  there  is.a large choice of
processes,  equipment and materials commercially  available for production units
of all sizes.   Considerations  of economic  and  technical viabilities under
individual  conditions may  limit  the choices.   Where  there, are no  technical
specifications  that  require post-solder  cleaning,  "no-clean"  techniques  are
often the'most  economical.  This technique is  recommended where the
reliability criteria can be met.   Where  cleaning is  a requirement,  the use of
water-soluble chemistry  has generally proved to  be preferable to  most of the
other processes,  although  it is  not a universal  solution.   There  is an
adequate  choice of other techniques where  neither  of these can be applied.

      The choice  of  substitute methods should  be subordinate  to environmental
considerations.   Due to  their harmful environmental  effects,  the  following
processes should  not be  selected for electronics manufacturing without a very
imperative  reason, especially as there are usually^ more benign processes
available that will  do the same  job.  The  Solvents,  Coating and Adhesives
Technical Options Committee does not recommend the following  processes in
electronics manufacture  for funding under  the  provisions of the Montreal
Protocol Multilateral Fund:

      •     HCFO-141b for  defluxing printed circuits
      •     Vapour-phase reflow  soldering
      •     Vapour-phase drying  of heavy organic solvents  using PFCs
      •     Vapour-phase drying  of water using MFCs  or  PFCs.

      Another factor which has become evident  only, in recent  years  is  that the
"operating window" of some substitute processes, including "No-Glean"  ones, is
considerably narrower than that  of traditional ones.  If the  process  is  not
perfectly mastered,  this^ may result in very significantly  increased operating
costs for rework.  One of  the parameters which can greatly influence  the width
of the "operating window"  is the design  of the assembly being processed.   The
design itself should be  optimised for the  process which will  be used  in  the
subsequent manufacture.  Changing from one process to another may require a'
re-design.  Fortunately, some of the better CAD  systems  permit, this switch
very rapidly by simple word processing in  text library  definitions  of  the
component "footprints" and in the rules  file.

      Finally, there are no technical obstacles  for  a complete  and  rapid
phaseout of ozone-depleting solvents in  the electronics  industry  in developing
nations,  as well  as  developed ones.  In  almost every case  it  is possible to
find substitutive processes that result  in significant  production cost
savings,  although they may require  a considerable capital  expenditure.
Amortisation of a correctly-chosen investment  is typically one  to three  years
but may require longer periods in exceptional  cases.  In a few cases,  there
may be increased  energy  requirements, but  the  cost of this  will be  more  than
offset by other production cost  savings.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     2-52

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                                   CHAPTER 3

                        PRECISION CLEANING APPLICATIONS
3.1.  BACKGROUND

      Precision cleaning applications are characterized by the high level of
cleanliness required to maintain low-clearance or high-reliability components
in working order.  They are used in.a variety of manufacturing industries,
such as in aerospace, microelectronics, automotive, and medical.  The primary
factor that defines the applications where a precision cleaning process is
required is high standards for the removal of particulates or organic residue.

      There are many types of contaminants that might be required to be
removed in a precision cleaning process.  These contaminants are generally
divided into either particulate contamination or npnparticulate contamination.
Particulate contamination is the type of contamination usually resulting from
a preceding manufacturing process,: such as cutting, drilling, grinding, or
buffing of component parts.  Nonparticulate contamination is usually composed
of organic residue, such as machining oils, waxes, finger print oil, and so
forth.

      As the term suggests, precision cleaning involves the cleaning of
components to a high standard of cleanliness.  One example of the cleanliness
required for a precision-cleaned component is provided in Figure III-l, which
shows the dimensional clearance on a computer disk drive.relative to the size
b,f various contaminants.  Tight dimensional clearances require the removal of
small particles that become lodged between the two surfaces.

      The factor that made CFC-113 the precision cleaning solvent of choice is
its remarkable chemical stability (manifested directly in its compatibility to
structural materials), its low toxicity, and zero flammabil'ity.  This has
allowed closed, superclean, white-room assembly areas to be operated safely
and effectively.  Probably the most essential example of solvent compatibility
is provided by CFC-113 in cleaning beryllium, particularly in the inertial
sensor industry.  As the performance requirements of gyros .increased for both
defence and aerospace applications, the need for a structural material that
combined low density with high dimensional stability also increased.  Hot
pressed beryllium has provided that material with a range of properties unique
among materials.  It has one distinct disadvantage -v- chemical reactivity,
especially with ionic chlorine.  The viability of CFC-113 as a pure, stable
solvent has allowed beryllium to be widely used as a structural material.  It
should be noted, however, that mixtures of CFC-113 with methanol will attack
beryllium very vigorously.
                                               \^
      1,1,1-Trichloroethane is the solvent of choice in some precision
cleaning applications.  Several of its physical properties --  higher
solvency, moderate evaporation rate, and higher boiling point -- make it a
unique product for cleaning some soils, such as heavy grease.
                    * 1994 UNEP SOLVENTS, COATINGS, AND'ADHESIVES REPORT *
                                      3-1

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                              Figure IU-1
    SIZE COMPARISON OF COMPUTER DISK DRIVE HEAD

        CLEARANCE WITH VARIOUS CONTAMINANTS
JJJJJJJJJJJJJJJJJJJJ
J-1-JJJJJJJJJJJJJUJJJJ
JJJJJJJJJJJJJJJJJJJJ
JJJ-J-IJJJJJJJJ-IJJJJJJ
J-l-iJJJJJJJJJJJJJJJJJ
  i- -; j-i J-l-i j j J JJJ J_i_l _l J,
   EDGE OF FLYING HEAD
       FLYING HEAD
       HEIGHT = 15-45
              MICRO IN
HUMAN HAIR
.003 IN. DIA.
                                   L1MT AND DUST
                      SMOKE PARTICLE
                      950 MICRO IN. DIA.
                                 FINGER
                                 PRINT
                                 SMUDGE
  OXIDE COATING (200 MICRO IN.)
  ALUMINUM SUBSTRATE SURFACE
                                                                 S1I02S-1
Source: Digital Equipment Corporation
 S18028-1
                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

                                   3-2

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      A number of companies have successfully tested and are currently using
CFC-113 and 1,1,1-trichloroethane alternatives to clean precision  instruments.
Companies also are implementing conservation and recovery practices  to reduce
solvent use in the short-term.  Possible alternatives include solvent and •
nonsolvent options.  Solvent options include aqueous and semi-aqueous,
alcohols, perfluorocarbons, synthetic aliphatic hydrocarbons,
hydrofluorocarbons (HCFCs) and their blends, and other miscellaneous solvents.
Nonsolvent options include supercritical fluid cleaning, UV/Ozone  cleaning,
pressurized gases, and plasma cleaning.  Although much testing still needs  to
be done for specific applications,1 the Committee consensus is that
alternatives will be substituted for CFC-113 and 1,1,.1-trichloroethane in
virtually all precision cleaning applications by the year 2000.


3.2   CFC-113 AND 1.1.1-TRICHLOROETHANE USE IN PRECISION CLEANING  APPLICATIONS

      3.2.1 Precision Cleaning Processes and Equipment

      To describe "precision cleaning", in a simple succinct way,is difficult.
To overcome this difficulty an integrated manufacturing system is  described in
which the differences in "metal cleaning" and "precision cleaning" become
apparent by the nature of the components and the cleaning process.

      Figure III-2 shows a diagram containing both metal cleaning  (parts
manufacturing) and precision cleaning (clean room assembly) processes.  In the
parts manufacturing segment, parts are manufactured, deburred, gauged, cleaned
using 1,1,1 trichloroethane, and stored.  In the eleanroom assembly areas,
parts and components are passed through a preliminary "goods inwards" cleaning
process using CFC-113 and then into final assembly and test.  In the final
assembly stages, mostly manual, multiple operations are carried out on a given
item and the parts are repeatedly cleaned using CFC-113, during and after each
assembly stage.  When complete the finished item is passed through
"acceptance" testing and inspection and then delivered either to detailed
functional testing or directly to the customer.  Functional rejects, occurring
during acceptance testing are often torn-down, recleaned, and returned, to the
assembly process.

      In the first stage, parts manufacturing, single' parts will be formed by
machining, stamping,  pressing, etc.  The cleaning requirements include the
removal of burrs and other mechanical residues as well as the removal of gross
residues of machining oils or other processing residues.  In this  stage,
vapour degreasing with 1,1,1-trichloroethane was a common practice.

      Within the clean room assembly area, CFC-113 cleaning would  normally
follow.  Its particular properties .of nonflammability, low toxicity, and low
odour allow it to be used in small cleaners within laminar flow cabinets or in
bench top units close to the operator's working position.  Typical'devices
made in such areas usually contain a wide range of materials.  In  addition,
many items are fixed using synthetic resins, local soldering operations on
custom-built hybrid devices are required, and many solvent sensitive polymers
     1  Testing heeds to be done not only to determine -cleaning effectiveness
but cost and environmental effects as well.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      3-3

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    Parts Manufacture
                  Figure ut-z

  Metal Cleaning and Precision Cleaning

                       Clean Room Assembly
          Machine
           Room
         Degrease
           Store
ource: Chem Systems 1989
 Currept
1,1,1 TCA
 future
 Semi-
Aqueous
                                                                                     Deliver
                       Current
                      CFC-113
                       Future
                Alcohol or Hydrocarbon
                                       BRITISH AEROSPACE
                                              DEFENCE
 SI8028-I
                       * 1994 UNEF SOLVENTS, COATINGS, AND ADHESIVES REPORT *

                                     3-4    .

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such as polycarbonate and polyether sulphones can be used.  The availability
of CFC-113 has obviously been vital in such an operation.

      Replacement of currently used solvents is relatively easy in the
"general cleaning" stage of manufacture.  Because the basic components are
usually one part-items, they can be cleaned very effectively using
alternatives such as aqueous and semi-aqueous systems.  If this system is
incompatible with the parts, due to corrosion sensitivity or shape
limitations, then solvents such as alcohols, HCFCs, and hydrocarbons can be
used, particularly with closed-type cleaning equipment now available to
minimise solvent emissions.

       Introducing alternative cleaning materials or processes is particularly
difficult in the final assembly precision cleaning area.  This is not due to
the nature of the soils involved, but due to the wide range of materials used
in the manufacture of the assemblies and the small clearances and complexity
found in such devices.

      Thus precision cleaning applications might include:

      •     Assembled units with complex shapes and small clearances
      •     A wide range of metallic and nonmetallic components, including
            many elastomeric materials
      •     Blind holes with capillary gaps which make evaporation of low
            vapour pressure fluids such as water impossible.

      Such work pieces are not always small; complete auxiliary power
generators and military aircraft generators can be immersion cleaned using
CFC-113 during maintenance operations, thus avoiding costly and risky
disassembly and reassembly of the units.  Alternative cleaning materials or
processes, therefore, are required to have low surface tension, low viscosity,
and relatively high vapour pressure.  Alternative processes must be designed
with new cleaning and drying technologies to be used with aqueous and semi-
aqueous cleaning systems.

      In the past, standard vapour degreasing equipment•was used in precision
cleaning processes.  The equipment is usually comprised of a boiling sump,
cooling coils, and a clean rinse stage with ultrasonic generators.  These
units were often fitted with mechanical handling equipment and installed at
the incoming location adjacent to clean areas so that parts, sub-assemblies,
and proprietary components could be cleaned and rapidly sealed in bags prior
to transfer to the clean room assembly area.  Within clean room assembly
areas, smaller CFC-113 and 1,1,1-trichloroethane vapour degreasers with
ultrasonic generators were often installed close to inspection and assembly
areas so that local batch cleaning could be performed.

      Bench-top ultrasonic cleaners are used in clean rooms and are often
installed within laminar flow boxes.  These ultrasonic units are cold cleaners
in which water is used as the energy coupling medium.  Clean glassware
containing a small volume of CFC-113, 1,1,1 trichloroethane, or other
nonflammable solvent is placed in the water such that ultrasonic energy can
agitate and clean the individual components when they are placed in the
solvent.  This type of cleaning has a high loss to evaporation; 100 percent of
the evaporated solvent is lost to the atmosphere because there are no cooling
coils -or other- forms of vapour containment or collection.  Often this


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      3-5  '

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technique is combined with particle counting in which all of the solvent is
microfiltered after cleaning so that the contaminant particles may be counted
under a microscope.     ,  .

      Gyroscope flushing tools are dedicated systems designed specifically for
a particular gyroscope.  Coupling fixtures attach these tools to the gyroscope
shell.  Clean .CFC-113 is forced through the gyroscope via ultra-filters under
pressure in an open-ended process to remove flotation fluid during rework or
to clean an assembly before filling it with oil.

      Hydraulic system flush and spray booths are similar to gyroscope
flushing tools but are larger.  The flush mechanism pumps CFC-113 through the
hydraulic systems to remove hydraulic fluid.  These cleaning machines often
have hand-held spray cleaners for manual cleaning of valve seats.  Many are
100 percent evaporative systems in which the solvent evaporates and is removed
from the work areas by extraction fans.  Similar techniques are used in the
refrigeration industry to flush out systems before filling.

      3.2.2 Precision Cleaning Applications
                     *
      Precision cleaning is discussed in this report in terms of the following
engineering applications:  cleaning precision instruments during
manufacturing, testing or assembly; cleaning during specialised manufacturing
techniques; and maintenance and repair cleaning.

      3.2.2.1     Cleaning Precision Instruments During Manufacture, Assembly.
                  and Testing      -

      Precision cleaning is used to remove contaminants from delicate and
complex instruments such as computer disk drives, inertial guidance systems
(gyroscopes), hydraulic control systems, optical components, and micro-
switches.  Traditionally, CFC-113 has been effective in precision cleaning the
following delicate instruments.                   '

      Disk Drives.  Disk drives are magnetic storage devices that store
information in computer systems.  Disk drives have a very small tolerance for
contamination during assembly.  Normally, the record/read head is spaced from
0.813 to 1.143 microns above the recording media surface of the disk
substrate.  To place this distance in perspective, smoke particles typically
are on the order of 6.3 microns in diameter. Contaminants must be controlled
at the submicrometer level for the drives to work effectively (Felty 1991).
Possible cleaning alternatives for disk drives include ultrapure water, semi-
aqueous processes, and organic solvents.

      Gyroscopes.   Precision cleaning is used to clean the mechanical
components of inertial systems, including gyroscopes and accelerometers.2
Parts are repeatedly cleaned at all stages of component assembly to remove
handling contamination and particulate material.  Repeated cleaning is
     2 Inertial guidance systems or gyroscopes, include rate gyroscopes,
displacement gyroscopes, and rate-integrating gyroscopes. .Displacement
gyroscopes typically are used in autopilots.  Rate-integrating  gyroscopes  are
used in precise inertial navigation systems  in missiles,  satellite  controls,
commercial aircraft, and underwater systems.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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important in gyroscope gimbal assemblies because suspension bearings
lubricated with solid film are sensitive to solid particulate contamination.
Cleanliness helps to assure torque values of a few microgram (mg) centimetres.
To reduce precessional drift, components have often been cleaned in small
ultrasonic cleaners using CFC-113.

      In rate-integrating gyroscopes, the flotation fluid surrounding the
inner gimbal is a poly (trifluorochloro) ethylene.  When the viscosity of the
fluid must be changed, secondary fluoropolymers are added.  Typically this
fluid is poly (l.l-difluoro)ethene.  Other fluorinated, high density
materials, such as perfluorotrialkylamines, are also used in the assembly and
testing stages.  A related advantage of CFC-113 is its solubility of these
high density polychlororofluoroethylene and polychlorobromoethylene compounds.
These compounds are not soluble in common solvents.

      Although the floated gyroscope' technology is being superseded by solid
state, optical systems, commercial and military gyroscope equipment will
remain in service for many years.  Because these gyroscopes need to be
serviced and maintained, there is a  long-term requirement.for compatible
solvents for manufacturing spare sensors and gyroscopes arid for cleaning
existing units.

      Possible cleaning alternatives for gyroscopes include nonozone-depleting
chlorinated solvents, organic solvents, hydrofluorocarbons (HFCs),
hydrochlorofluorocarbons (HCFCs), aqueous processes, supercritical fluids, and
perfluorocarbons (PFCs).

      Hydraulic Control Systems.  Hydraulic military vehicle control systems
have control valves with extremely small diameter bores as well as parts such
as 0-ring seals and gaskets made of  elastomers.  These systems are flushed to
remove the working fluid and to remove all particulate contamination during
assembly, after functional testing,  and during field maintenance.  CFC-113 has
traditionally been the solvent of choice because of its chemical stability and
noncorrosive properties.  Smaller tactical weapon systems often use a gas
control system in which a source of  high pressure gas, either chemically
generated (e.g., extruded double-based propellent) or a "cold" compressed gas
such as nitrogen at 3.56 x 107 N/M2,  controls the  actuator systems'  valves.
Gas controls require extreme cleanliness as  they are sensitive to particulate
contamination.  Gas control systems  are pressure tested, and water often is
used as the test fluid.  Many hot'gas control units have long blind holes from
which it is difficult to remove water by oven evaporation.  Water-displacing
mixtures based on CFC-113 effectively dry these systems.

      Possible alternatives for hydraulic control system cleaning include
alcohols, supercritical fluids, and  gas plasma.

      Optical Components.  CFC-113 solvent and alcohol azeotrope or surfactant
solvents along with 1,1,1-trichloroethane are widely used in cleaning and
fixturing processes during grinding  and polishing operations and prior to
applying vapour deposition coatings  in optics fabrication.  The surface
cleanliness of glass and metal optical elements are critical to ensure     '
adequate adhesion of optical coatings and freedom of movement in low torque
pivots with small clearances.
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      Solvent cleaning has been an integral part of the manufacturing cycle
for optical components.  Solvents used  included 1,1,1-trichloroethane,
trichloroethylene, CFC-113, CFC-113 with  the azeotropes of methylene chloride,
acetone, methanol, ethanol and CFC-113  dispersions with water and surfactants
as well as individual solvents as methylene chloride,, acetone and methyl,
ethyl, and isopropyl alcohols.  Historically solvents have been  the preferred
method due to their speed of soil removal, known material compatibility, lack
of residual contamination, ease of use, and low cost.  Regulatory changes  in
purchase and disposal of these materials  is dictating a change to alternative
cl'eaning techniques.  These changes will  not be without their associated
problems.

      Typical part holding (blocking) techniques are used during precision
optical grinding and polishing operations utilizing rosin and paraffin-based
waxes, pitches, and some cyanoacrylate  adhesives.  In particular, the waxes
and pitches are used for their ability  to conform  and hold to a  variety of
irregular shapes and surface textures.  The blocking technique involves
heating the part and tooling, applying  a  layer of wax to the tool surface,
installing the part, and then allowing  the tool to cool before subsequent
processing.  The waxes and pitches are  also nonreactiye with water-based
coolants and slurries used during the grinding and polishing of  optical
elements.  Cyanoacrylate adhesives are  used during a limited number of
operations where precision tolerances.are required, but are limited by their
ability to withstand the dynamic loading  and shocks encountered  during some of
the manufacturing procedures.

      After processing, part removal  is similar to the blocking  technique.
The tool is heated, the blocking wax  or pitch softens or melts,  the part is
removed and both part and tool are cleaned.  The use of a solvent vapour
degreaser allows streamlining of the  cleaning sequence since all operations
can be performed in a single machine.   When the parts/tools are  removed from
the degreasing operation, they are clean  and ready for additional processing
steps such as vapour deposition of specialized coatings.

      The use of cyanoacrylates as blocking agents requires some form of
solvent cleaning to remove all residues prior to additional processing.  Much
of this cleaning is performed in soak hoods where  the contaminated optical
element is immersed in solvent or where direct manual cleaning is employed
using acetone.  Other processing techniques that are dependent on the use  of
solvent cleaning are the application  of protective coatings used during
fabrication operations to protect finished surfaces.  The current selection of
coatings used are solvent based and are resistant  to water, again a
requirement due to the use of water-based coolant  and processing fluids.

      Some water-based cleaning is currently in use for rough cleaning
operations prior to final, fine cleaning  operations.  Problems have been noted
with residues left after using water-based cleaners prior to vapour deposition
thin film coating operations.  The negative impact of these residues on the
adhesive strength of thin film coatings deposited after such operations has
prevented their use in final, fine, or  finish cleaning procedures.  The    .
reduced adhesion and increased propensity for peeling of the coating is
particularly noticeable when completed  optical elements are exposed to
elevated temperature and humidity conditions.                        •
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       Water-based cleaners also suffer from material compatibility problems.
 There  are  well  over 100 types of visible glass and infrared materials
 (germanium metal,  etc.) used in precision optical elements.   The need for
 precise  process control,  minimization of staining on optics,  difficulties with
 rinsing  and drying (formerly used chlorofluorocarbons (CFCs)),  and equipment
 reliability problems associated with utilization 'of aqueous cleaners have
 forced manufacturing in'many instances to return to manual final
 cleaning/drying operations utilizing acetone and alcohol solvents to replace
 CFCs.

       The  change from solvent cleaning' to alternative methods  will require
 significant process changes in the future to completely remove CFCs and 1,1,1-
 trichloroethane from the precision optics manufacturing process.  Blocking
 materials,  protective coatings, and techniques for final cleaning before
 coating  will require change.   Material compatibility, cleanliness,  and process
 stability  will  be critical considerations for any replacement  cleaning
 solvent.            .                                .
                        /

       HCFCs may provide an alternative for final cleaning operations after wax
 and other  blocking and grinding/polishing residues have been removed.   Testing
 (Schaefer  and Scott 1991) has indicated that the three-carbon HCFC-225 solvent
 is  equivalent to CFC-113 in its ability to provide final cleaning before and
 after  vapour deposition coating operations without introducing stains due to
 solvent  evaporation.  Cleaning equipment used for CFC-113 can also be used for
 HCFC-225 because the boiling point is slightly, higher than'CFC-113.   It is
 important  to'operate the equipment,  however, with a recovery system to
 minimize solvent emissions (Yamabe 1991).3  Newly designed,  closed-type
 equipment  is also available to reduce solvent emissions.  Initial testing has
 shown  the  HCFC-225 to exhibit very poor solubility with the typical blocking
 waxes  and  pitches used in the optics manufacturing operation;  solvent blends
 and new  soluble blocking 'materials are being developed to overcome this
"difficulty.   In order to use HCFCs throughout the fabrication cycle, new
 compatible (soluble) blocking materials will have,to be developed.

       Recently,  manufacturers of .glass-based optical elements  have shifted
 away from  CFC-113 cleaning solvents..  The use of chemically inert CFC-113
 solvents is critical for metal-based optical elements such as  highly polished
 or  diamond turned (machined)  aluminum reflective elements.  The highly
 sensitive  metal surfaces are extremely reactive in a fresh,  nonoxidised state,
 and cleaning with substitute chlorinated' solvents would detrimentally affect
 the metal.  HCFC-225 has also been evaluated as,replacement for CFC-113 (in
 part due to similar boiling points)  in this operation and found to be
 compatible with the freshly machined surface and capable pf final'cleaning of
 such surfaces without generating stains during solvent flash-off.

       Other alternatives, known as hydrofluorocarbons (HFCs)  and
 perfluorocarbons (PFCs),  have been developed for use in the precision cleaning
 of  optics  as well.  PFCs are currently commercially available.,  and HFCs are
 expected to be  available commercially in the next one to two years.   Both HFCs
 and PFCs exhibit low reactivity, vapour pressures similar to that of CFC-113,
 and relative nonflammability.   PFCs. have been used for many years as
      3 HCFC-225ca and  cb have been  registered  in  EINECS,  Toxic  Substances
 Control  Act  (USA)  and  in Japan.

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 insulating and drying fluids,  although the use of PFCs in emissive         l
 applications such as solvent cleaning is limited.   Both HFCs and PFCs, which
 do not contribute to stratospheric ozone depletion or to the formation of
 tropospheric ozone (smog),  have been identified as global warming compounds..
 PFCs are more potent global warmers than HFCs because their atmospheric
 lifetimes are significantly longer than those for HFCs.  Newly designed
 equipment is available to aid potential users of either PFCs or HFCs. .The new
 equipment is vapour-tight and usually includes options for solvent filtration
 and recycling within the unit.

       Gas plasma cleaning has  become more popular in the mid-1990's for
 general precision cleaning of organic contaminants based on the use of the
 technology developed in the electronics industry in the 1980's.  Gas plasma
 cleaning requires the use of oxygen, carbon tetrafluoride/oxygen, or other
 gases,  to remove trace amounts of organic material.   The gas plasma is created
 when normal gases are excited above their normal energy levels.  The
 excitation of the gases results in the creation of excited oxygen molecules,
 which then react and oxidize organic molecules to form carbon dioxide and
 water vapour.  Gas plasma cleaning will damage all amorphous carbon-based
 materials and therefore .should not be used with components containing
.plastics.  This type of cleaning finds its way into all of the cracks and
 crevices of a particular component and is ultimately removed by creating a
 vacuum on the cleaning chamber.  Waste disposal is generally not a concern
 with gas plasma cleaning as the waste components are only the small amounts of
 contamination or dirt collected in the gas plasma air filter.

       Pressurised CFC-113 is also used for cleaning dust and particles from
 high definition cathode ray tube shadow works and electron guns.  CFC-113
 solvent is very efficient as the high specific gravity allows nonmetallic
 particles to be floated off precision parts (Nemoto 1989).

       In the past, CFC-113 was used in many drying operations to prevent
 streaking and water spot deposition on pre- and post-coat'ed optical element
 surfaces.  Many of these applications, however, have been replaced with high
 vapour pressure organic solvents. In such applications, since these materials
 are considered volatile organic compounds (VOCs),  vapour retention is critical
 to prevent the emission of solvent vapours to the atmosphere 1

       Possible alternatives for optical component cleaning include
 supercritical fluids, high-purity alcohols, HCFCs, and PFCs.

       Electrical Contacts.   Micro-switches used for critical switching
 functions require extremely clean contacting surfaces.  CFC-113 often is used
 to clean these surfaces.  The switches also can be cleaned using CFC-113 after
 assembly to remove particles or oily.material deposited during assembly.

       Most electrical contacts in connectors, slip-rings, potentiometers,
 microswitches,  and relays have precious metal contacts such as gold, gold
 alloys,  and platinum metals.  Precious metal contacts are used in the defence
 industry where "single shot" devices require a^long storage life  (up to 15
 years)  and must operate .with greater than 99 percent reliability.  High
 surface contact resistance is a problem as many of these devices are closed
 "cold"  (i.e., without an applied voltage) because of safety requirements.  In
 the past these specifications were met by CFC-113 cleaning.  CFC-113 also was
 used to clean sliding contacts such as slip rings and potentiometers.


                     * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT, *
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      Possible alternatives for electrical contact cleaning include
supercritical fluids, gas plasma, HCFCs, high purity organics, and nonozone-
depleting chlorinated solvents.

      Medical Equipment Applications.  The small blind holes  increasingly
found on complex surgical equipment have made it difficult to remove the water
from this equipment.4  A majority of surgical instruments were first dried
using CFC-113 water-displacing materials and then were sterilised.
Orthopaedic prostheses such as hip joints and knee joints are cleaned and
dried using a similar process.  CFC-113 was also used to clean pipe-runs,
bedside control systems, and main control panel equipment after installation
and during maintenance cleaning of hospital piped-oxygen systems.  HCFCs and  t
PFCs can now be used to clean and sterilize these systems.  The high
volatility and nonflammability of CFC-113/ HCFCs, and PFCs allows the flushing
solvent to be blown through the oxygen system without risk of explosion.
Vacuum drying can be used to' eliminate any risks of leaving trace amounts of
solvent.  The chemical stability of CFC-113, HCFCs, and PFCs and the absence
of stabiliser chemicals helps ensure that organic contaminants can be removed
from the metal parts of the oxygen systems without risk of corrosion.
 V       .                            '
      Possible alternatives for the cleaning of medical equipment include
supercritical fluids, gas plasma, high-purity alcohols, HCFCs, PFCs, organic
solvents, and vacuum drying.                  '  '    .

      Plastic Assemblies.  CFC-113 was'used to remove mould release agents
from a variety of plastic mouldings such as ABS electronic cabinet mouldings,
domestic white goods accessories, medical parts, syringes, spoons, bottles,
and sample vials.  The advantage of using CFC-113 in this application is that
there is no risk of surface attack or "crazing," which could occur if other
solvents are used without considering material compatibility issues.

      Possible alternatives in this applications include nonozone-depleting
chlorinated solvents and organic solvents where compatible.

      3.2.2.2     Specialised Manufacturing Techniques

      Precision cleaning also is a component of specialised manufacturing
techniques such as auto-rivetting of commercial aircraft wings and precision
application of special lubricants.  .These options are also discussed in
further detail in Chapter 9: Other Uses of CFC-113 and 1,1,1-trichloroethane.

      Auto-Rivetting.  Commercial aircraft wings often are used as fuel tanks.
These wings, therefore, must be of minimum weight and maximum strength, have a
long corrosion-free life, and be fuel tight.  Auto-rive'tting is used to meet
these requirements.5  Traditionally, major aircraft companies have used CFC-
113 for auto-rivetting because the stock being drilled for commercial aircraft
     4 In the past, surgical instruments were dried after washing and then
sterilized in hot  air ovens.                                          •

     5 In this process,  the wing skins are clamped to the stringers, a double
counter sunk hole  is drilled through both components, and an appropriate rivet
slug-is placed, into the bore and the head machined flush with the outer wing
surface.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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wings is much thicker than that on the wings of fighter aircraft.  A
proprietary CFC-113 solvent blend is sprayed on the drill  tool  during  cutting
and on the rivet slug as it is placed into the bore.  Although  the rivet  slug
is anodised, the freshly drilled bore surface is not protected.  The solvent
spray protects the assembly as it is formed and frees the  joint of entrapped
moisture or acidic components that might encourage corrosion.   The solvent
rapidly evaporates and helps cool the form.

      A possible alternative for this application is the use of rivets with
dry film lubricants.

      Application of Special Lubricants.  The surface of miniature precision
bearings is coated with a thin oil film.  T9 ensure that the film remains
stable over many years of storage life, a lubricant such as a CFC-113  solvent
solution is sometimes applied to the bearings.  The low surface tension of
CFC-113 solvent allows the solution, to  "wet" the bearing almost instantly.
The rapid solvent evaporation leaves a  film of oil on the  bearing surface.
Perfluoroether and cyclopentane-based lubricants, which are used in some  space-
applications due to their extremely low vapour pressure and flat temperature -
'viscosity curve, use CFC-113 as a carrier for thin film application and to
clean bearings as these lubricants are  only soluble in a select few organic
solvents.

      3.2.2.3     Maintenance Cleaning  and Repair

      Maintenance precision cleaning applications include  avionics equipment,
glove boxes in the nuclear industry, electronic sensors associated with
offshore oil rigs such as remote cameras and well loggers, and  reticles used
to manufacture semiconductors.

      In the past, large commercial airline workshops used large amounts  of
CFC-113 solvents to clean avionics equipment.6  In the nuclear  power
industry, pieces of ancillary equipment that become contaminated with
radioactive dusts are removed in glove boxes using remote  handling systems.
With continued use, the boxes themselves become contaminated.   Glove boxes  can
be decontaminated by spraying with CFC-113 to remove radioactive dusts.   The
low surface tension and high volatility of CFC-113 provide good wetting and
penetration for particle removal.  The  low flammability and low toxicity  of
CFC-113 were the main reasons for using CFC-113 on offshore oil rigs where
CFC-113~was used to clean sensors such  as remote cameras,  drill head attitude
indicators, and well loggers.  Pressurised CFC-113 was used for cleaning  dust
and particles from reticles used during the manufacture of semiconductors.
The reticle is a patterned glass plate  through which light is directed on
wafers to create circuitry.  CFC-113 solvent is very efficient  as the  high
specific gravity allpws nonmetallic particles to be floated off reticles
(Nemoto 1989).
 .  '  6 Larger aircraft components are cleaned using other chlorinated solvents
such as trichloroethylene and perchloroethylene  in vapour degreasers  and
1,1,1-trichloroethane in cold cleaning  and vapour degreasing.

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 3.3   ALTERNATIVES FOR REDUCING OR REPLACING CFG-113 AND 1.1.1-TRICHLOROETHANE
       IN PRECISION CLEANING

       CFC-113 and 1,1,1-trichloroethane have evolved as the preferred solvent
 cleaning method in precision cleaning because of their chemical inertness; low
 toxicity, nonflammability,  low surface tension, and low .water solubility.
 However, to eliminate CFC-113 and 1,1,1-trichloroethane use, a number of
 companies have tested and implemented alternative cleaning methods.  Possible
 alternatives include solvent and nonsolvent options.  Solvent options include
 other organic solvents (such as alcohols and aliphatic hydrocarbons),
 perfluorocarbons,  HCFCs and their blends,  and aqueous and semi-aqueous
 cleaners.  Nonsolvent options include supercritical fluid cleaning, UV/Ozone
 cleaning, pressurized gases, and plasma cleaning.  Solvent use may also be
 reduced by controlled planning of repetitive or multiple cleaning operations.
 These alternatives are discussed later in this chapter.     ,

       Generally, the selection of the most appropriate alternative to either
 CFC-113 or 1,1,1 trichloroethane should be made based on a number of factors,
 including technical feasibility, environmental, health, and safety impacts,
 and cost.  Technical feasibility can be predicted by the use of solubility
 parameter technology, such as Hildebrand parameters.  This process is very
 simple and has proven to be accurate in many cases.  The basic process
'requires the identification of the solute,^.or contamination, that is to be
 removed from a particular surface.  Next,  the solubility parameter of the
 solute is determined and matched to the solubility parameters of hundreds of
 common industrial solvents.  Several common solvents are selected and the
 properties of each should be closely reviewed.  Finally, one or two solvents
 can be selected for testing on actual hardware.  This is a scientific process
 on how best to narrow the selection of alternative solvents.  For more
 information on this process, con'sult "Handbook of Solubility Parameters and
 Other Cohesion Parameters",- Allan F.M. Barton, CRC Press.

       3.3.1 Conservation and Recovery Practices

       Solvent losses are often large in conventional or poorly maintained
 plants.  In a poorly maintained plant, 20 percent or less of ,the purchased
 solvent is generally recovered.

       Depending on what measures have already been adopted at a plant,
 applications of the guidelines summarized in Appendix C can enable total
 emissions to be reduced by up to 90 percent.  Solvent losses can be reduced
 from 2-5 kg/h-m2 of bath area with conventional practice to 0.2 -  0.5  kg/h-m2
 of bath area.  For certain alcohol and partially aqueous systems,  the overall
 base rate of annual loss is around 0.03 -  0.05 kg/h-m2 of bath area.

       The recommendations summarized in Appendix C can be implemented to
 reduce solvent use in cold cleaning,  vapour degreasing, and continuous in-line
 cleaning.

       3.3.2 Aqueous Cleaning

       Aqueous cleaners use water as the primary solvent.  Synthetic detergents
 and surfactants are combined with special additives such as builders,  pH
 buffers, inhibitors,  saponifiers, emulsifiers, deflocculants, -complexing
 agents, antifoaming agents, and others.  They provide .multiple options in


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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formulation blending, such as the use of corrosion inhibitors and pH buffers.
Table III-l summarizes the advantages and disadvantages of aqueous cleaning.

      The key stages of an aqueous cleaning process are washing, rinsing,
drying, water treatment, and waste recycling/disposal.  Although each of these
steps in Figure III-3 is an important and integral part of the aqueous
cleaning system, rinsing and drying may not be necessary in all circumstances
and wastewater disposal may also be integrated into the other steps by
recycling bath contents and the overall water use.

Process Equipment

      Aqueous cleaning equipment can be characterized as:

      •     In-line equipment used for high throughput cleaning requirements

      •     Batch equipment used for low throughput such as for maintenance
            applications or smaller production processes.  The in-line and
            batch equipment can be further subdivided into immersion, spray,
            and ultrasonic type equipment.  Table III-2 summarizes the
            advantages and disadvantages of each of these three types of
            equipment.

      Product design can have a significant influence on cleanability.   Choice
of materials and configuration should be reviewed if possible for
opportunities to make changes that can have a major influence on the success
of aqueous cleaning. Care should be exercised to prevent trapping cleaning
fluid in holes and capillary spaces.  Low surface tension cleaning solvent
might penetrate spaces and not be easily displaced by the higher surface
tension pure water rinse.  Penetration into small spaces is a function of
surface tension, viscosity, and capillary forces.

      Water-based cleaning is a more complex process than CFC-113 and 1,1,1-
trichloroethane cleaning.  Good engineering and process control are much more
critical to prevent problems.  Useful parameters for process control include
bath temperatures, pH,  agitation, rinse water quality, and cleaning bath
quality.

      Drying presents one of the major challenges to aqueous cleaning for
complex parts and may require considerable engineering and experimentation.
However, there are some aqueous cleaning systems in operation today in
precision cleaning applications that produce spot-free drying.  There have
been significant changes in the area of spot-free drying over the last several
years, and there are commercially available systems that will spot-free dry
almost any component.

      Aqueous cleaning requires careful consideration of drying.
Thermodynamic or evaporative removal of bulk water is usually not practical
from the perspective of an energy or process time.  Mechanical removal of the
water (90 percent or more) can be accomplished in some cases using compact
turbine blowers with filtered output.  Design options include variation of
pressure, angle, velocity, and volume.  Other sources of air include dedicated
compressors or plant air, but care must be taken to remove oil, particles, and
moisture to the level desired.  Economics and.noise reduction are other
considerations in using such options.  (Depending on the equipment and plant,


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                                                   Table 7/7-7
                                       AQUEOUS CLEANING
  ADVANTAGES
DISADVANTAGES
  Aqueous cleaning has several advantages over organic
  solvent cleaning.

  •    Safety —' Aqueous systems have few problems with
      worker safety compared to many solvents. They
      are not  flammable or explosive. Toxicity is low for
      most formulations, requiring only simple
      precautions in handling any chemical.  It is
      important, however, to consult the material safety
      data sheets for information on health, safety, and
      environment regulation.

  •    Cleaning -- Aqueous systems can be readily
      designed to clean particles and films better than
      solvents.               '

  •    Multiple Process Options  -- Aqueous systems have
      multiple process options in process design
      formulation arid concentration.  This enables
      aqueous processes to provide superior  cleaning for
      a wider variety of contamination.

  •    Inorganic or Polar Soils — Aqueous cleaning is
      particularly good for cleaning inorganic or polar
      materials. For environmental and other reasons.
      many machine shops are using or convening to
      water-based lubricants and coolants versus oil-
      based. These are ideally suited to aqueous
      chemistry.

  •    Oil and Grease Removal - Organic films, oils,
      and greases can be removed very effectively by
      aqueous chemistry.

  •    Multiple Cleaning Mechanism - Aqueous cleaning
      functions by several mechanisms rather than just
      one (solvency), including saponificatioh (chemical
      reaction), displacement, emulsification, dispersion,
      and others. Particles are effectively removed  by
      surface activity coupled with'the applicatipn-t>f
      energy.

  •    Ultrasonics Applicability - Ultrasonics are much
      more effective in water-based solvents  than in
      CFC-113 solvents.

  •    Chemical Cost - Low consumption and
      inexpensive.
Depending upon the specific cleaning application, however,
there are also some disadvantages.

•  Cleaning Difficulty -- Pans with blind holes and small
   crevices may be difficult to clean and may require
   addition of a vacuum dryer.

•  Process Control - Aqueous processes require careful
   engineering and control.

•  Rinsing --Some aqueous cleaner residues can be
   difficult to rinse from surfaces.  Nonionic surfactants
   are especially difficult to rinse. Trace residues  may not
   be appropriate for some applications and materials.
   Special precautions should be applied for parts
   requiring subsequent vacuum deposition, liquid oxygen
   contact, etc.  Rinsing can be improved using deionized
   water or alcohol rinse.

•  Floor Space -  In most  instances, aqueous cleaning will
   require more floor space..

•  Drying - For certain part geometries with crevices and
   blind holes, drying may be difficult to accomplish. An
   additional drying section may be required.

•  Material Compatibility  —• Corrosion of metals or
   delayed environmental stress cracking of certain
   polymers may occur.

•  Water.-- In some applications high purity water is
   needed.  Depending on purity and volume, high purity
   water can be expensive.

•  Energy Consumption -- Energy consumption may be
   higher than solvent cleaning in applications  that require
   heated rinse and drying stages.

•  Wastewater Disposal ~ In most  instances use of
   aqueous cleaning will require wastewater treatment
   prior to discharge.

•  Water Recycling  - Wastewater may be recycled.  Cost
   of equipment and maintenance can be moderately
   expensive.
Source:  Adapted from ICOLP.
                               1994 UNEP  SOLVENTS, COATINGS, AND ADHESIVES  REPORT
                                                       3-15

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                              Figure 111-3

       CONFIGURATION OF A TYPICAL AQUEOUS
                      CLEANING PROCESS
       Parts from
      Manufacturing
        Process
        Solution
     Racirculation:
 Filtering, Skimming
                   Wash
                   Stage:
                Heated Detergent
                Solution: Spray.
                Immersion
                Ultrasonics, etc.
   Rinse
   Stage:
   Water:
Spray. Immersion
  Dryer:

Room Temp Air
Heated Air.
or Vacuum
                     Periodic Removal
Cleaned
Parts Ready
for Continued
Production
                  Waste Treatment
                                                                    HMB-2
Source: EPA1989a
              * 1994 UNEP SOLVENTS, COATINGS. AND ADHESIVES REPORT *
                               3-16

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                                   Table 7/7-2

             AQUEOUS CLEANING  PROCESS EQUIPMENT
  IMMERSION WITH
    ULTRASONIC
     AGITATION
     IMMERSION
 WITH MECHANICAL
     AGITATION
   SPRAY WASHER
ADVANTAGES
Highest level of
cleaning; cleans complex
parts/configurations

Can be automated

Parts can be welded

Usable with parts on
trays

Low maintenance
Usable with parts on
trays

Will flush out chips

Simple to operate

Cleans complex parts
and configurations

Might use existing
vapour degreasing
equipment with simple
engineering  changes
High level of cleanliness

Inexpensive

Will flush out chips

Simple to operate

High volume

Portable

Short lead time
DISADVANTAGES
Highest cost .

Requires rinse water for
some applications

Requires new basket
design

Long lead time

Cannot handle heavy
oils

Limits part size and tank
volumes

Separate dryer may be
required
Requires rinse water for
some applications

Harder to automate

Requires proper part
orientation and/or
changes while in solution

Separate dryer may be
required
Requires rinse water for
some applications to
prevent film residues

Not effective in cleaning
complex parts

Separate dryer may be
required
                  * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                    3-17

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humidity  and air-conditioning  control  as well as  associated economics may be
an  issue.)  Centrifugal drying is  another useful  option  for the  mechanical
removal of water  from  complex,  robust  parts. Evaporative drying  following
mechanical removal  can be  accomplished using infrared, clean dry air-heated or
ambient temperature, or vacuum-heated  drying.   Dryers can be designed in-line
or  batch.  Drying design should always be confirmed with experimentation.

      A very effective means of completely  removing water from,  or  drying,
objects with either simple or  complex  geometries  is the  use of a vacuum oven.
The amount of vacuum and the temperature together with the  length of time an
object is left within  the  vacuum oven  are variables.  They  should be matched
to  the complexity of the object and  the nature  of its construction  (Baxter
1991).

      Wastewater  minimization  and  treatment is  an important consideration and
is  discussed in detail later in this report.

      Successful  cleaning  of both  disk-drive parts and gyroscope components
using aqueous detergent processes  has  been  reported.  One major  company has
switched  from a CFC-113 disk drying  process to  a  hot water/air drying system
for some  applications  (Wolf 1988).   Aqueous ultrasonic cleaning  also has been
successfully used to clean inertial  guidance and  navigation systems and
components that are used in some missiles and aircraft in the U.S.  Department
of  Defense inventory (Patterson 1989).

      Alternatives  to  CFC-113  cleaning of inertial systems,  gyroscopes,
accelerometers, and related gaskets, bearings,  and housings include
biodegradable aqueous-based systems  and nonchlorinated/halogenated
hydrocarbons such as alcohols,  ketones (acetone), hydrocarbon/surfactant
blends, and petroleum  distillates.   The alternatives may be a combination of
systems using ultrasonics,  high pressure sprays,  surfactants, and ancillary
equipment.  The following  contaminants have been  successfully removed using
aqueous detergents  and ultrasonics:

            A highly fluorinated,  long chain polymer lubricant
            Polychlorotrifluoroethylene, a  viscous heat  transfer
            fluid with a low coefficient of expansion  •
            Long  chain hydrocarbon oils/grease
            Finger  prints
            Inorganic  particulate  matter
            Rust  and other oxides
            Some  carbonaceous  char.

      The cleaning  equipment used  was  a self-contained system that  cleans
with detergents and water  in a cylindrical  cleaning tank agitated by
ultrasonics.  This  aqueous system  not  only  has  offset use of CFC-113 and
1,1,1-trichloroethane, but has reduced process  time as well.  For example,
while manual cleaning  of gimbal rings  takes approximately 15 minutes per ring,
an  aqueous ultrasonic  system can clean 24 rings in 25 minutes.

      The cleaner provided better  cleaning  results than  those achieved  with a
solvent-based system.  The self-contained system  is a promising  spray booth
.media for cleaning  parts which cannot  be subjected to ultrasonics and also  for
bench use where spot cleaning  is done  as part of  the repair process.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      3-18

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       Nuclear  decontamination  may  be  effectively achieved  by  an aqueous-based
system  and high pressure  sand  blasting.  Also,  A1203  and/or  glass  beads  of *
0.1  mm  have been used  successfully.    In this process,  the  water evaporates and
the  residue is cast for disposal  (Arvensen 1989).

       3.3.3 Semi-Aqueous  Cleaning      v

       Hydrocarbon/surfactant cleaners,  one type of emulsion cleaner that  can
substitute for CFC-113 and 1,1,1-trichloroethane in precision cleaning
applications,  have been included  in a number of different  cleaners formulated
for  different  purposes.   Hydrocarbon/surfactants are used  in  cleaning
processes  in two ways:   They are  either emulsified in  water solutions and
applied in a manner similar to standard aqueous cleaners or they  are  applied
in  concentrated form and  then  rinsed  with  water.   Because  both methods use
water in the cleaning  process,  the hydrocarbon/surfactant  process  is  commonly
known as a semi-aqueous process.7
        Under certain circumstances,  it may be possible to modify an existing single or multi-stage vapour,
degreaser for use with an alternative  solvent.  For alternative cold dip cleaners such as hydrocarbons, the
vapour degreaser will be used primarily as a containment vessel and the ancillary features such as heaters,
etc., are not required.  It may also be possible to adapt a multi-stage degreaser for use with the newly
emerging semi-aqueous cleaning processes.  The details of the conversion procedure will depend on the type
of process being'Considered but the following guidelines illustrate the principles.

A.      Semi-Aqueous  Processes

        Halbgenated solvent degreasers are usually fitted with heaters, some form  of condensing coils  water
cooled or refrigerated, safety cut-out devices and in some cases,  ultrasonic agitation and/or pumping and
spraying equipment.

        As halogenated solvents are non-flammable, the equipment designed for'their use will have electrical
equipment that will not be certified for use in flammable areas.  The semi-aqueous processes use flammable
fluids.  Though the fluids are normally used below the flash point, consideration should be given to a
situation where the flash point may be exceeded.   In this situation, equipment may have to be modified so
that it shuts down  in a safe controlled manner.

        Process.   Semi-aqueous processes consist  of one or  two immersion stages in the proprietary
hydrocarbon formulation followed by rinsing in one or two stages of water.   Drying is usually required.

        The degreaser should  have sufficient compartments to accommodate'the chosen semi-aqueous process
commensurate with the level of cleanliness required.

        Cleaning Stage.  The  proprietary semi-aqueous cleaner  is contained in the  first stage(s).  Should
heating be required then it will need  to be determined whether there is sufficient heat input with the
existing heating arrangements.  Temperatures of 30-50°C are  typical, however terpene-based solutions can be
used unheated.  -It may be necessary to include some form of  cooling in the event that introduced parts are
warm or to counteract excessive heat.input from pumps, ultrasonics, etc.

        A control  system will need to  be installed to control  the temperature to 20°C below  the flash  point
of the semi-aqueous material.  .The existing safety cut-out may form part of this system.  In addition, a
back up system should be fitted which  would shut the system  down and sound an alarm should the temperature
reach 10°C below the flash point of the cleaner.

        Rinse Stage.  Water can be circulated or  agitated with ultrasonics in the  remaining  stages of  the
cleaning equipment.   It may be necessary to heat the water using the existing heaters to achieve good
rinsing and to assist in dry off.  There may be significant  drag out of the wash liquid"into the rinse
stages. . Water may be re-circulated or passed to drain depending on the process  requirements.  If the water
is to be re-circulated, then appropriate ion exchange or membrane technology may need to be  installed to
keep the water clean.  Similarly, this may be required prior to disposal.

        The advice of both the manufacturer of the semi-aqueous cleaning fluid and the degreasing equipment
should be sought before attempting such a conversion (Johnson 1991).

B.      Alcohol Process                                        •   .       '

        Conversion of standard halogenated solvent degreasing  equipment  for use with alcohols  inerted with
perfludrocarbons is not practicable (Johnson 1991).  However, some companies have successfully modified

                        *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                           •    3-19

-------
      The  benefits of semi-aqueous cleaning processes  include the following:

      •     Good cleaning ability (especially  for  heavy grease,  tar, waxes,
             and hard to remove soils)
      •     Compatibility with most metals and plastics
      •     Suppressed vapour pressure  (especially if  used in emulsified form)
      •     Nonalkalinity of process prevents  etching  of metals,  thus helping
             to keep metals out of wastestrearns
      •     Reduced evaporative loss
      •     Potential decrease in solvent consumption  which may lower overall
             cost
      •     Ability of some formulas to decant easily  from water.
      •     Lower water consumption as compared  to aqueous cleaning

The drawbacks  include:

      •     Recycling or disposal cost of wastewater could make the process
             less economically viable
      •     Flammability concerns if concentrated  cleaner is used in spray
             cleaners; however, the flammability  issue  can be solved with
             improved equipment design
             Objectionable odours with some cleaners such as terpenes
             VOCs make up some cleaners
             Drying equipment will be required  in most  applications
             Gelling of some cleaners at low water  solutions
             Difficulty in reducing surfactants used in cleaners
             Toxicity considerations not yet established
             Auto-oxidization of some cleaners.   For example,  d-limonene (a
             type of terpene) can auto-oxidize.   The terpene suffers auto-
             oxidation naturally from contact with  air.   This can in some
             instances be reduced using antioxidant additive
      •     Semi-aqueous cleaning systems may  require  more floor space in some
             instances
      •     Energy consumption may be higher than  that of solvent cleaning
             systems in applications that require heated rinse and drying
             stages
      •     In some applications, high purity  water which is expensive may be
             needed.                                                        •

      The  steps  in a typical semi-aqueous cleaning process resemble those in
aqueous applications.  Most equipment designed for use with semi-aqueous
processes  are  also similar to aqueous cleaning equipment designs.  Figure
III-4 shows  the  schematic for a typical semi-aqueous cleaning process.

      The  four major steps used in the cleaning  process are washing (with a
hydrocarbon/surfactant),  rinsing (with water), drying,  and wastewater
disposal.  In  cases where extreme cleanliness  is required,  the
hydrocarbon/surfactant cleaning can be followed  by a fully aqueous wash step
with an alkaline detergent and a deionized water rinse.   As in aqueous
cleaning,  it is  important to note that both the  wash and the rinse stage are
recirculating;  these solutions are not continuously discharged.
their vapour degreasers for cold cleaning with isopropanol.  The refrigeration system of the units remain
connected but the heaters are disconnected. This maintains the solvent at more than 20°F below its
flashpoint.  The equipment is also electrically grounded.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      3-20

-------
                    Figure 111-4

      SEMI-AQUEOUS PROCESS FOR
  IMMISCIBLE HYDROCARBON SOLVENT
Hydrocarbon/
 Surfactant
 Wash Stage
Emulsion
 Rinse
Rinse
  Dryer
Forced Hot Air
                                               Cleaned
                                               Part:'
Hydrocarbon/
 Surfactant

  Reuse
 Dispose or
 Recycle
                   Decanter
                               (T) Qeaed Loop Water
                                 Treatment

                               0 Site Water
                                 Treatment or

                               (T) Direct to Drain
                                                    tlMM-11
     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                    3-21

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      In the wash step,  the hydrocarbon/surfactant cleaner is applied to the
part being cleaned with some form of mechanical energy.  As a result of the
hydrocarbon/surfactant cleaner's high solvency and low flash points, the
solvent bath is generally not heated; however, some are slightly warmed when
the cleaner is used in a diluted form.  Such cleaners are ignitable and should
not be used in vapour or spray cleaning without inert atmosphere or other
protective equipment.  Some semi-aqueous cleaners have flash points above
93°C and can be used hot.  Application methods that avoid misting such as
spray-under immersion, spin-under immersion, or ultrasonics should be used.

      The dilute hydrocarbon emulsion cleaners formulated with water may be
heated.  Less mechanical energy is needed when using a hydrocarbon/surfactant
solution as compared to an aqueous solution because of the high solvency of
hydrocarbon/surfactant cleaners.

      The clean water rinse step removes the residues left by the wash step.
When concentrated hydrocarbon/surfactant cleaners are used, the rinse step is
necessary because these cleaners have a low volatility which prevents them
from evaporating from the parts cleaned in the wash stage.  The rinse step may
not be necessary when dilute hydrocarbon/surfactant emulsion is used if the
level of cleanliness does not require removal of the residue from the wash
stage.  In some instances alcohol is used as a final rinse step.  The rinse
step may also serve as a finishing process and in some instances is used to
apply rust inhibitors to the parts.

      The drying step serves the same function-as it does in aqueous cleaning.
Water is removed from the part to prepare it for further processing or to
prevent rusting.  Heated air and high velocity room temperature air are the
principal drying agents.  The drying step may not be needed if the parts are
rust inhibited and can air dry.

      The wastewater disposal step is always an important part of the cleaning
process.  Most of the contaminants in the wastewater are removed by decanters
and filters as the solution is recirculated in the' tank.

      Because some hydrocarbon/surfactant cleaners can easily be separated by
decantation from the rinse water.  The rinse water may be recycled or reused,
and the waste hydrocarbon/surfactant can be burned as fuel.  In such cases,
contaminants like oil and grease, removed from the part being cleaned, are
retained in the hydrocarbon/surfactant phase, thereby greatly reducing the
contaminate loading in the water .effluent.

      Equipment for use specifically with concentrated hydrocarbon/surfactants
is available.  As with aqueous cleaning, this equipment can be classified as
immersion or spray equipment, and further as batch or In-line equipment.
Although there is a temptation to use existing aqueous equipment for the
hydrocarbon wash unit, this application is potentially dangerous because of
flammability.

      Immersion equipment, the simplest design used in hydrocarbon/surfactant
cleaning, works with, but is not limited to, dilute emulsion solutions which
do not present the combustion (flammability) danger of the concentrated
hydrocarbon/surfactants.  It can also be used with concentrated
hydrocarbon/surfactant cleaners.  This equipment may operate in batch or in-
line configurations.  Some old solvent vapour degreasers can be retrofitted to


                    * 1994 UNE'P SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     3-22

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immerse the parts into the bath of emulsion cleaner. The parts are simply cold
dipped into the bath, which may or may not be heated.  Because of the solvency
of the hydrocarbon/surfactants, very little mechanical energy needs to be
added to achieve adequate cleanliness.  Higher cleanliness can be achieved by
adding agitation to the process, either mechanically with ultrasonics or by
heating the wash solution.
                                                                              \
      As with aqueous cleaning, the mechanical spray action improves the
cleaning performance of the solution.  When using concentrated hydrocarbon/.
surfactants, the atomized solution is prone to combustion and special care
must be taken to prevent it.  Nitrogen blanketing is used to remove oxygen
from the spray chamber and the chamber, both of which are enclosed to prevent
sparks from entering.

      In some instances, "spray-under immersion" can be performed.  In this.
equipment, high pressure spray nozzles are placed below the surface of liquid.
This prevents the formation of atomized solution and eliminates flammability.

      As in any cleaning application, keep in mind that the best process can
be ineffective when used ,on poorly designed parts.  Any process can be
improved by a design that reduces the cleaning challenge.  This is an
important factor, both economically and functionally, and can often be done
with low cost during product design.

      3.3.4 HCFCs

      HCFCs are transitional alternatives since their ozone depletion
potential (ODP) values, though small, are not zero.  Because of their ODP,
HCFCs were recently added to the list of controlled substances under the
Montreal Protocol.  As a result, they are subject to a phaseout by the year
2030, with a 99.5% reduction by the year 2020.  Nevertheless, they have the
excellent physical properties of CFCs, such as low surface tension and
nonflammability.  It is expected, therefore, that some of them can be used in
certain applications with minimal or no process.changes.

      Several HCFCs (e.g., HCFC-225ca/cb, HCFC-141b, and HCFC-123) have been
proposed as possible CFC-113 and 1,1,1-trichlorqethane substitutes.  Table
III-3 shows the physical properties of some of these chemicals and compares
them with CFC-113 and 1,1,1-trichloroethane.  (Note that HCFC-225 is a mixture
of two isomers, ca and cb, hereafter referenced as HCFC-225.)  A typical
composition of HCFC-225 commercially available is a 45/55 percent mixture of
the ca/cb isomers.  ODP and toxicity of several of these HCFCs will most
likely greatly limit or completely eliminate their potential for replacing
CFC-113 and 1,1,1-trichloroethane in solvent cleaning applications.  Two major
manufacturers have limited or cancelled their production, of HCFC-123:  DuPont
will not offer HCFC-123 for cleaning operations, and Allied-Signal has
withdrawn all HCFC-123 formulations from the market.  In addition, DuPont has
said that they will not offer any products containing HCFC-141b.

      The advantages of HCFCs in the precision cleaning include the following:

      •     they exhibit moderate to good cleaning performance
      •     the CFC-113 cleaning equipment can be used with minor or no
            modification
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      3-23

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                                      Table III-3

                    PHYSICAL PROPERTIES OF HCFCs
              AND OTHER OZONE-DEPLETING SOLVENTS
                   CFC-113
              1,1,1-
              Trichloro-
              ethane
              HCFC-225ca    HCFC-225cb    HCFC-141b
Chemical Formula

Ozone-Depleting
Potential

Boiling Point (°C)

Viscosity (cps)
@25°C

Surface Tension
@ 25° C (dyne/cm)

Kauri-Butanol
Value

Flash Point °C

Toxicity
CCI2FCCIF2
0.8


47.6

0.68


17.3


31


None

Very Low
. CH3CCI3
 0.1


 73.9

 0.79


 25.56


 124


. None

 Low
CF3CF2CHCI2    CCIF2CF2CHCIF   CH3CFCI2
-0.01


51.1

0.58.


15.5


34


None

Moderate
 -0.04


 56.1

 0.60


 16.6


 30


. None

 Low
0.11


32.0

0.43


18.4


76


None

Low
                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                        3-24

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       •     any assembled units  with complex shapes  and very small clearances
             can be  cleaned well
       •     the energy consumption of HCFC cleaning  systems may be relatively
             small as  compared with those of aqueous  and semi-aqueous systems
       •     they are  compatible  with most metals and plastics
       •     HCFC cleaning requires less floor space  relative to aqueous and
             semi-aqueous  cleaning
       •     drying  is .easy and the, assembled units leave no cleaning stains
             since no  water is used during the cleaning process •.

       The  disadvantages of HCFCs include:

       • •    they are  a transitional solution;  the Montreal Protocol has urged
             parties to phase-out HCFCs in the period 2020-2040;  HCFC-141b has
             an'ODP  slightly higher than that of 1,1,1-trichloroethane
       •     they are  volatile and expensive;  therefore they usually require
             retrofitting  of the  existing equipment or new cleaning equipment;
             a recovery system will be necessary to minimize the solvent
             emissions
       •     they may  not  be useful in some applications where 1,1,1-
             trichloroethane is used                ;
       •     they are  incompatible with acrylic resins
       •     toxicological testing for HCFC-123,  HCFC-141b,  and HCFC-225
             resulted  in moderate controls being recommended for these
             solvents.

       HCFC-225 is characterized by the equivalence of CFC-11-3 in physical
properties with'ODP values one twentieth that of CFC-113 (Table III-3).  It is
expected,  therefore,  that HCFC-225 can be used in most applications where CFC-
113  is used without any changes  of equipments and processes.  Equipment
changes would be required, however,  to reduce emissions of HCFCs from the
equipment.   Applications  where HCFC-225 might be used include precision
cleaning of disk drives,  gyroscopes, hydraulic control systems,,  optical
components,  electric  contacts, plastic assemblies, and applications of special
lubricants.   Evaluations  of HCFC-225 in all these applications are currently
in progress.

       As mentioned  in section 3.2.2.1, recent testing (Schaefer and Scott
1991)  has  indicated that  HCFC-225 is equivalent to CFC-113.in the ability to
provide final cleaning before and after vapour deposition coating operations
without introducing stains due to solvent evaporation.  Successful cleaning of
both hard  disk drive  and  hard disk using HCFC-225 has also been reported.
Some companies are  intending to  switch from CFC-113  to HCFC-225 in those
applications without  a process change.  So far;  HCFC-225 has received good
evaluations as a substitute, for CFC-113 in various applications of precision
.cleaning.   There are  certain applications in precision cleaning where aqueous
and  semi-aqueous systems  cannot  be applied, and HCFC-225 is emerging as a
promising  substitute  in those applications.
       It-has  also been reported that HCFC-225 exhibits poor solvency in some
applications.   For example,  initial testing has shown the HCFC-225 to exhibit
poor  solubility with the typical blocking waxes and .pitches used in the optics
manufacturing operation.   HCFC-225 is compatible with most metals and plastics
but may damage acrylic resins.   It cannot, therefore, be applied for cleaning


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES  REPORT *.           .
                                      3-25  '

-------
assembled units where acrylic resins are used as the essential material.
Compatibility of HCFC-225 with materials which are used in the assembled units
to be cleaned should be tested carefully.  It has been confirmed that  recovery
systems for CFC-113 can also be applied for HCFC-225.  Also, the recovery
system for HCFC-225 has been developed with a 95 percent recovery rate (Yamabe
1991).

      The high volatility of some HCFC cleaning solutions require special
equipment design criteria.  In addition, the economic and environmentally  safe
use of HCFCs may require special emission control features for vapour
degreasers (see Figure III-5).  These include:

            Automated work transport facilities
            Hoods and/or automated covers oh top entry machines
            Facilities for work handling that minimize solvent entrapment
            Facilities for superheated vapour drying
            Freeboard depth to width ratios of 1.2 to 2.0
            A main condenser operating at 7.2° to 12.8°C
            A secondary condenser operating at -34° to -29°C
            A dehumidification condenser operating at -34° to -29°C  (optional)
            Seals and gaskets of chemically compatible materials
            Stainless steel construction
           •Welded piping containing a minimum of flanged joints
            A refrigerated desiccant -dryer for methanol blends
            A cool room to work in
            Carefully controlled exhaust from the refrigeration unit to
            prevent excessive heat from reaching the separator chambers.

      Retrofitting or purchasing a new piece of.equipment for use with HCFCs
is recommended in many applications.  Material compatibility is another
important consideration.  HCFC-141b requires compatibility testing with
magnesium, zinc, and other metals.  In addition,  the HCFCs have shown  some
adverse effects with plastics such as ABS, acrylic, and Hi-Impact Styrene.
Like metals,  plastics need to be tested on an individual basis.

      The use of HCFCs in cleaning equipment may be viewed in terms of two
distinct equipment categories -- new equipment and retrofitted equipment.
Design changes are much easier to implement in new equipment.  For example,
dual sump open top degreasers (batch units) can have the same working  area but
different length and width.  A degreaser with the lesser width will be more
solvent efficient in terms of diffusion losses.  It would be impractical,
obviously, to consider reorienting sumps on an existing machine in order to
take advantage of this design feature.  New batch units have the vapour
generation sump offset from the rest of the machine, again to help minimize
solvent losses.  Other features on new equipment are:  roll-top lids,  gasket-
sealed water separator lids, and a P-trap installed in the water drain of  the
water separator.  These features help economize on the use of solvent.  A heat
exchanger can be used to keep the rinse sump of a batch cleaning unit  lower
than the boiling point of the solvent by about 10 degrees fahrenheit (24°C).

      Some of the features mentioned above (e.g., the roll-top lid, gasket-
sealed water separator lid, and P-trap/water drain of the water separator) are
readily applicable to retrofitted equipment.  In-addition, it is relatively
easy to extend the working freeboard.  Freeboard height is the distance from
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     3-26

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                               Figure 7/7-5

            ADVANCED DESIGN DEGREASER FOR
          USE WITH LOW BOILING POINT SOLVENTS
         Hooded Work Transporter on Open-Top Degreaser
    Hood

      \
                    Work Transporter
                              .Additional
                              Freeboard
                       , Diffusion
                       Control
                       . Coil -20-F
Freeboard
  Depth'
                                                            Dehumldlfler
                                                            Coll
                                                            -20-F
      Source: DuPont
  Main
Condenser
40"-50»F
                                                            Heating
                                                            Coll
                                                               staooeui-n
|05(»>-U
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

                               3-27

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the vapour-air interface line (generally at about the second primary condenser
coil) to the lip of the machine.  The freeboard ratio is the freeboard height
divided by the narrowest dimension of the machine, which is normally the
machine width.  Freeboard ratio is normally expressed as a percentage.

      3.3.5 Alcohols and Ketones

      The most common organic solvents are alcohols such as ethanol,
isopropanol, and several glycol ethers (methyl, n-butyl, and diethyl).'  Most
of these solvents are chosen for their high polarity and for their very
effective solvent power.  The alcohols have a range of flash points and care
must be exercised while using the lower flash point alcohols (see Table
III-4).

      Based on material compatibility, alcohols are viable alternatives for
component cleaning.  Explosion-proof boiling alcohol cleaners using
isopropanol could.be a practical alternative to CFC-113 and 1,1,1-
trichloroethane in many applications.  For bulk cleaning of parts at the
incoming stage, this alternative could be considered; large-scale isopropanol
use may be unacceptable within,clean room areas, however, because of
flammability risks and operator discomfort resulting from alcohol odours as
well as the dehydrating effect of alcohol solvent and vapours on skin
surfaces.

      Isopropanol and acetone operating in conjunction with ultrasonics have
been evaluated as alternatives to CFC-113 in precision cleaning (Mobjork
1989).  Care must be taken when using flammable solvents in ultrasonic baths
due to the potential for solvent ignition and fires.  The following components
and instruments were subjected to overall evaluation in this testing:

            Servo component system
            Hydraulic series ram screw
            Accelerometer cut-out
            Horizon indicator
            Horizon gyroscope
            Gyroscope motor components
            Flight position indicator
            Turn and bank indicator
            Reduction vent valve for oxygen
            Oxygen pressure regulator
            Parachute swivel connector.

      All components and instruments were retrieved from production except  for
the oxygen vent and pressure regulator which were manually contaminated.  Due
to the flammability of isopropanol and acetone, special explosion-proof batch
vapour-phase cleaners were used in this evaluation.8  A number of precision
components were cleaned in isopropanol or acetone.
     8 These ultrasonic vapour-phase cleaners are designed for flammable
liquids.  The 'machines are fire- and explosion-proofed  according  to  the  DIN-
standards and approved by the Federal Republic of Germany's TUV authority.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     3-28

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                                      Table IJI-4
                         PROPERTIES  OF ALCOHOLS
Product
Methanol
Ethanol, Prop. Anhydrous
Ethanol, Spec. Industrial Anhydrous
Isopropanol, Anhydrous
n-Propanol
2-Butanol
Isobutanol
n-Butanol
Amyl alcohol (primary)
Methyl Amyl Alcohol
Cyclohexanol
2-Ethylhexanol
Hexanol
LB/GAL
15.6°C
6.60
6.65
6.65
6.55
6.71
6.73
6.68
6 75
6.79
6.72
7.89
6.94
7.90
SP. GR
20°/20°C
0.792
0.799
0.795
' 0.786
0.806
0.809
0.803
0.811
- 0.815
0.808
0.949
0.834 '
0.950
Boiling
Range °C
64-65
74-80
75-81
82-83
96-98
97-102
107-109
116-118
127-139
130-133
160-163
182-186
244-247
FL PT.
"CTCC
12
9
10
12
23
22
29
. 36
. 49
39
61
73
1202
Evap.Rate1
3.5
1.8
1.8
1.7
1.0 .
0.9
0.6
0.5
0.3
0.3
0.05
0.01
0.002
1  N-Butyl Acetate = 1.'
2 C.O.C.
Note: FL. PT. = Flash Pointed Closed Cup Test; SP.GR. =
Source: Southwest Chemical Company, Solvent Properties
Specific Gravity. .
Reference Manual
                      * 199'f UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                         3-29

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      Cleaned with isopropanol:

      •     Swivel connector parts contaminated with low
            temperature grease
      •     Gyroscope instruments
      •     Reduction vent valve connections in an oxygen system
            contaminated with oils and greases
      •     Oxygen system gas regulators contaminated with soot
            and char.

      Cleaned with acetone:

      •     Servo-gear piston contaminated with anti-corrosion oil
      •     Series servo contaminated with hydraiulic oils, grease,
            and particulates
      •     Accelerometer cut-out contaminated with silicone oil.

      Isopropanol proved to be a viable substitute for CFC-113 and generally
is compatible with nonmetallics.   However, the use of acetone as a viable
alternative needs to be studied carefully since it is highly aggressive  toward
many polymers.

      3.3.6 Perfluorocarbons

      The perfluorocarbons (PFCs) are a group of fluorine-saturated
hydrocarbons (compounds in which all the hydrogen atoms of the hydrocarbon  are
substituted by fluorine).  Because of the extreme electronegativity of the'
fluorine atom,  this saturation results in high chemical stability in all of
the compounds.   Consequently, they are virtually chemically inert, exhibit  low
toxicity, are nonflammable, and have zero ozone-depletion potential.  As a
result of this very low chemical activity, PFCs can be used in medical
applications and are safe in contact with pure oxygen at high pressures.
Their stability, however, makes PFCs extremely potent global warming
compounds.  Due to their high global warming potential (GWP), the use of PFCs
is being restricted in a number of countries.

      Choice of base hydrocarbon provides a wide range of molecular weight  and
molecular structure resulting in a range of boiling points.  Table III-5 shows
some of the basic properties of PFCs that were commercially available in late
1994.

      Besides their GWP, another major disadvantage of PFCs is their high cost
which is a result of the complex synthetic production processes.  A typical
low- to mid-range boiling PFC,  for example, is approximately 326 to $40  US  per
kg (late 1994).   The high -cost of these compounds -should encourage potential
users to use PFCs only in vapour-tight equipment, reouci ig the amount of PFCs
that are lost to the atmosphere.   Another drawback is that PFCs have very low
solvency power for hydrocarbons and are unlikely to be very useful for
removing oils.   They have been shown, however, to be excellent solvents  for,
perfluoropolyethers and other halogenated compound;..

      Where no other substitutes are feasible, PFCs offer possible solutions
to current CFC-113 and 1,1,1-trichloroethane users, particularly in cleaning
parts .for high accuracy gyros.   Some current high density flotation fluids  are
soluble in certain PFCs, which can therefore be used for flushing filled


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     3-30

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Table 7/7-5
Properties of Perfluorocarbon Solvents Available in 1 994
Basic Formula
Ozone Depletion Potential
Global Warming Potential1
Boiling Point, °C
Density, g/ml, 25° C
Viscosity, cP, 25°C
Surface Tension,
dynes/cm, 25°C
Silicone Solubility
Fluorocarbon Solubility
Solubility Parameter, H
Flash Point, °C
Approximate Cost, US$/kg
C5F1lN0
Q
6000
50
1.70
0.68
13.0
Very Low
High
6.3
None
23
Vl4
0
5200
56
1.68
0.67
12.0
Very Low
High
5.6
None
23
C7F16
0
49002
80
1.73
0.95
13.0
Very Low
High
5.7
None
23
C8F18
0
47002
101
1.77
1.4
15
Very Low
High
5.7
None
23
CFC-113
0.8
4500
47.6
1.57
0.68
19.0
High
High
7.3 .'
None
22
1,1,1-
Trichloro-
ethane
0.10
100
73.9
1.33
0.79
25.6
Moderate
High
7.7
None
7
1
  Based on 100-year time horizon.
  Estimated

Source: 3M
                          * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT
                                                 3-31

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 assemblies.   In addition,  high pressure spraying with PFCs appears to be a
 very effective method of particle removal.   The excellent chemical stability
^df these fluids makes them compatible with all gyro construction materials
 including beryllium.  Table III-6 summarizes the compatibility of PFCs with
 various materials.

       Design of equipment for gyroscope or other precision parts cleaning will
 have to.'be specific to each application,   whatever type of equipment is
 designed,  it should be a vapour-tight system to facilitate reclamation and
 recycling.   The chemical stability of PFCs makes them excellent compounds for
 recycling.   Currently, suppliers offer reclamation and recycling programs for
 these compounds,  thus minimizing emissions that could contribute to global
 warming.9   If vapour-tight equipment  is not utilized,  the evaporative loss of
 PFC would be prohibitively expensive  and would make the use of PFCs very
 difficult to rationalize (even considering the high cost and strategic
 importance of the  products).

       3.3.7 Isopropyl Alcohol Cleaning with Perfluorocarbon

       Alcohols such as ethyl and isopropyl have been used extensively for
 cleaning printed circuit boards and precision components.  They are very
 effective in removing rosin and polar activators commonly used in flux.
 Safety is the primary difficulty in using alcohols because of their high
 flammability.  In order for alcohols  to become viable options, both flame and
 explosion proofing are necessary expenditures to prevent- operator injury and
 equipment damage.   Using a perfluorocarbon (PFC) "blanket" in suitable
 equipment renders  the alcohol vapour  nonflammable, and results in a safer
 alcohol vapour degreaser.

       The advantages of using this type of process include:

       •     Isopropyl alcohol, being  extremely polar,  has good solvency and
             allows for the removal of differing types of particulate and
             organic contamination than CFC-113.

       •     PFCs are nonflammable, have low toxicity and reactivity, and have •
             zero ozone-depleting potential. v

       •     The nonflammable nature of the alcohol-PFC vapour allows a safe,
            -continuous distillation at a lower temperature than isopropyl
             alcohol alone with rapid  rinsing to give a dry product.

       •     PFC and isopropyl alcohol are virtually non-immiscible; PFC being
             more dense forms a layer  below the alcohol.  If this lower PFC
             layer  is heated to its boiling point (approximately 50°C),  the
             vapour generated will entrain the alcohol to form a mixed .vapour
             with approximately five percent alcohol at a temperature of 50°C.
             This layer is  nonflammable.
     9 Preliminary studies by one  equipment manufacturer have  demonstrated
emission  reductions  of 90 percent  for PFCs compared to historical emissions of
CFC-113.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT  *
                                      3-32

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                                        Table III-61

                PERFLUOROCARBON (RFC) COMPATIBILITY
                           WITH VARIOUS MATERIALS
        Class of Material
  Rubbers

  Polyethylene, polypropylene

  Nylons

  Polystyrene

  "Perspex" ("Plexiglass")

  FIFE (unfilled)

  PVC (Rigid)

  PVC (Rexible)

  Electronic circuit boards*

  Copper and brass

  Other Common metals

  Silicone and microcircuit chips

  Adhesives
  Adhesive tapes
  Paper
  Enamelled wires
  Insulating tapes
  Paints
  Other surface coatings and sealants
                  Observation
< 1 percent linear swell, _+ 1 percent change in weight

< 1 percent shrinkage, zero change in weight

Negligible change in dimensions or weight

Variable, generally negligible, shrinkage (e.g., 0.2 percent)

<0.2 percent shrinkage, slight loss in weight

2-3 percent linear swell, up to 10 percent increase in weight

Negligible change

Extraction of plasticizer, loss of flexibility (in hot Flutec)

±_ <0.1 percent dimensional change, zero change in weight

Slight tarnishing (from dissolved oxygen)

No effect detectable

No known effect

1

I No adverse effects detected in any samples  tested up to the
\ present time
  * Including:  SRBP, Epoxy, DAP, Silicone, Melamine, Polyester, with filler materials of all common
  types.
Source:  Rhone  Poulenc,  ISC  Chemicals Division.
                       * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES-REPORT *
                                           3-33

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      •   -  Alcohol and PFC are. "clean" agents; i.e., they leave no residue.
            They also evaporate readily at,low temperatures.

      •   •  Additional features of some equipment include a hermetically
            sealed lid, under lid basket operation, and a balancing volume  to
            accommodate volume changes on heat-up and shut-down.   Superheated
            PFC spray can alsc be used to facilitate removal of isopropyl
            alcohol from cleaned parts.

      The disadvantages include:

     . •     A properly designed, dedicated piece of equipment consisting of a
            conventional two-tank vapour degreaser with a boiling  alcohol
            (soiled .solvent) tank and a pure hot alcohol rinse tank is
            required to operate this process.

      •     Safety systems must be designed to automatically cease operations
            should the PFC level drop below the level necessary to prevent
            explosion.

      •     Pure alcohols are not effective at removing nonpolar contaminants
            like grease and flux residue.  However, cleaning effectiveness  can
            be enhanced by combining the alcohol/PFC cleaner with  a precleaner
            unit using hydrocarbons or other solvents.               - ,

      •     PFCs have a high global warming potential and atmospheric
            lifetime.

      •     PFCs are expensive, currently priced from US$26.00/kg.

      3.3.8 Aliphatic Hydrocarbons

      Aliphatic hydrocarbons, which offer tighter control on composition,
odour,  boiling range, evaporation rate, etc., are employed in original
equipment manufacturer (OEM) cleaning processes and will be discussed below.
The advantages of aliphatic hydrocarbon cleaners include.:

            Compatible (non-corrosive) with most rubbers, plastics and metals
            Employs no water, hence can clean water-sensitive parts
            Low odour and low toxicity grades available
            Reduced evaporative loss
            No wastewater stream
            High stability and recovery         "~
            Recyclable by distillation
            Good cleaning ability for wide variety of soils,'especially heavy
            grease, tar,  waxes, and hard to remove soils.  Low surface tension
            allows good penetration.

      The disadvantages include:                   ,

      • •    Flammability concerns (can be solved with proper, equipment design)
      •     Slower drying times than halogenated solvents
      •     VOC control may be required.  However,, equipment,such  as carbon
            adsorption and condensers can recover solvent from effluent air
                    * 199
-------
       •     Low occupational exposure limits are associated with some grades.
       •     Waste products are classified as hazardous waste

       A wide range of aliphatic hydrocarbon solvents are used in precision
 cleaning (see Table III-7)!  Petroleum fractions, commonly known as mineral
 spirits or naptha, are used extensively in maintenance cleaning.  These are
 single stage, open top processes using ambient air drying.  In most cases such
 processes are not suitable for Original Equipment Manufacture (OEM) cleaning.

       The major steps in the hydrocarbon cleaning process are washing (1-3
 stages depending on degree of cleaning needed) with a hydrocarbon cleaner,
 drying using forced air,  VOC recovery from solvent-laden air, and waste -
 solvent recovery or disposal.  The wash steps involve liquid-phase cleaning at
 temperatures sufficiently below the flash point of the fluid.  Ultrasonics or
 other agitation processes such -as immersion spraying, parts rotation,  or fluid
 pump around can be used to augment cleaning action. (However, note that
 ultrasonic equipment manufacturers do not recommended the use of ultrasonics
 with flammable solvents.)  Spraying or mistingvprocesses,  where fine droplets
 are formed, should be employed only in an inert environment or with equipment
 otherwise protected from ignition conditions, because fine- droplets can be
 ignited at temperatures below bulk fluid flash point.

       Fluids with flasTi points near 40°C (104°F)  or below should be used in
 unheated equipment operating at ambient temperatures, although the continued
 use of refrigeration coils is preferred.  For higher flash points, hot
 cleaning can be employed to boost cleaning action.  For systems with good
 temperature control (independent temperature sensors, cutouts, level
 indicators, etc.), a safety margin of 15°C (59°F) between the fluid flashpoint
.and the cleaning temperature, or 90 percent below the lower explosive  limit
 (LEL),  is recommended.  For systems with poorer temperature control, a higher
 margin should be employed.                                    .

       Each wash step should be followed by a drain period, preferably  with'
 parts rotation, to minimize solvent dragout from stage to stage. ,

       In multistage processes, fluid from one bath is periodically transferred
 to the preceding bath as  its soil level builds up.  Fresh solvent is thus
 added only to the final bath to ensure the highest parts cleanliness,  and
 spent solvent is only removed from the first stage.

       The drying step normally uses forced air which may be heated.  Either
 the dryer should operate  at 15°C below the flash point of the fluid, or
 sufficient air flow should be provided so that the effluent air composition is
 well below the.Lower Explosive Limit (LEL) of the system.
                                                                    'i
       The VOC recovery step is an important part of the cleaning process.
 Depending on the solvent  chosen, either carbon adsorption or condensation are,
 the best technologies for recovery of solvent vapours from spent drying air
 and lip vent air.  There  are numerous vendors of such recovery equipment.

       In the waste recovery area, the best reclamation technology for  these
 products is usually filtration and distillation.   One of the advantages of the
.low olefin content and narrow distillation range is that the recovery  in
 distillation is high.  Should some disposal of residual solvent be necessary,
 fuel substitution or incineration are good routes.


                     * 1994  UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      3-35

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                                     Table III-7
                  PROPERTIES OF ALIPHATIC SOLVENTS
Product
Mineral Spirits
Odourless Mineral Spirits
140 Solvent
Kerosene
C10/C11 Isoparaffin
C13 N-Paraffin
C10 Cycloparaffin
LB/GAL
15.6°C
6.37
6.33
6.54
6.60
6.25
6.35
6.75
SP. GR
15.6/15.6
°C
0.764
0.760
0.786
0.790
0.750
0.760
0.810
Boiling
Range °C
152-202
. 177-202
182-210
166-257
160-171
227-238
166-182
FL. PT.
'CTCC
41
53
60
. 54
42
93
41
KB
32
27
30
30
29
22
54
Evap
Rate1
0.1
0.1
0.1
0.19
0.3
0.1
0.2
1  N-Butyl Acetate = 1.  .
Note: FL PT. = Flash Point Closed Cup Test; KB = Kauri-Butanol Value; SP.GR = Specific Gravity.
Sources:  Southwest Chemical Company, Solvent Properties Reference Manual; Exxon Chemical Company
                      * 1994 UNEF SOLVENTS, COATINGS,  AND ADHESIVES REPORT *
                                         3-36

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       3.3.9  Chlorinated and Other Miscellaneous Organic Solvents

       The  precision cleaning industry has always used a very wide range of
miscellaneous  solvents.   In all applications such solvents are used for manual
operations,  usually by means of camel or sable .hair brushes during assembly or
.rework.  In  addition to those already described, ot'her chlorinated solvents,
ethers,  ketones,  alcohols,  and esters-,  are also candidate replacements for
precision  applications.   Typical uses are local defluxing after solder rework'
operations,  defluxing after special solder operations (e.g., strain gauge lead
attachment), and varnish applications (e.g., small scale in-situ coil
impregnations).

       The  chlorinated solvents that do not destroy the ozone layer —
trichloroethylene,  perchloroethylene, and methylene chloride (dichloro-
methane) — also  are effective cleaners.   Because of their widespread use, they
have  been  scrutinized for their .safety,  health, and environmental impacts.
Many  countries have established exposure levels that are considered safe for
workers.  In addition,  many countries have placed additional controls on
emissions  to the atmosphere from processes using these solvents.  Local
regulations,. Material Safety Data Sheets, and industrial recommendations such
as  those of  the  American Conference of Governmental Industrial .Hygienists
should be  used as guidance in establishing safe handling and usage procedures
for these  solvents.
                                  \
       The  development of extremely low emissions cleaning equipment which
minimizes  worker exposure levels, and emissions to the environment, along with
good  management  practices offers users an alternative that provides for
equivalent or  better cleaning with existing technology.  The combination of
limits being placed on users will require their use.only in applications where
emissions  are  very carefully controlled.  Table III-8 summarizes the
properties of  these other chlorinated solvents.

       The  ketones (see Table III-9) form a group'of very powerful solvents.
In  particular, acetone (dimethyl ketone) and methyl ethyl ketone are very good
solvents for polymers and adhesives.   In addition, acetone is an efficient
dewatering agent.  However, their extreme flamm'ability' (note that acetone has
a flash  point  of -18°C)  and incompatibility with many structural polymers
(e.g., stress-cracking of polyether sulphone, polyether ketone, and
polycarbonate) means that they should only be used with care and in small
.quantities.  Consequently,  large-scale use as CFC-113 or 1,1,1-trichloroethane
alternatives would be unlikely.

       Esters such as dibasic esters have good solvent properties.  Most of
these materials  are readily soluble in alcohols, ketones, ethers, and most
hydrocarbons,  but are only slightly soluble in water and high paraffinic
hydrocarbons.  The materials have high flash points and low vapour pressures.
Dibasic  esters,  however, are so low in vapour pressure that a residual film
will  remain  on a surface after application.  In addition, they have been found
to  be genotoxic  and should therefore be used with caution.

       3.3.10      Pressurized Gases

       Particulate contamination may be removed with pressurized gases, as an
alternative  to cleaning with CFC-113 and 1,1,1-trichloroethane.  However, the
use of these gases will not generally remove ionic or organic contamination


                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
  .              '                      3-37

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                                        Table III-8

           PROPERTIES OF  HALOGENATED CHLORINATED
                                      SOLVENTS
Physical Properties    CFC-113
               1,1,1-
               Trichloro-
               ethane
               Trichloro-
               ethylene
               Perchloro-
               ethylene
               Methylene
               Chloride
Ozone-Depleting
Potential
0.8
Chemical Formula    CCI2FCCIF2

Molecular Weight     187.38

Boiling Point (°C)     47.6

Density (g/cm3)      1.56

Solubility Parameter,  7.7
  Hildebrands
Surface Tension
(dyne/cm)
17.3
Kauri Butanol Value   31

Toxicity              Low

Carcinogenicity       No

Flash Point (°C)       None
0.1
               CH3CCI3
133.5

72-88

1.34

9.2


25.4


124

Low

No

None
0

CHCICCI2

131.4

86-88

1.46

9.3


29.3


130

Medium

See Note8

None
                             CCI2CCI2
165.9

120-122

1.62

9.7


31.3


91

Medium

See Noteb

None
               -0
               CH2CI2
84.9

39.4-40.4

1.33

9.7


N/A


132

Medium .

See Note6

None
a The U.S. EPA has not formally classified trichloroethylene in Category B2 as a "probable human carcinogen,' while the
International Agency for Research on Cancer (IARC) has classified this solvent in Group 3, a substance not classifiable as to
its carcinogenicity in humans.

b The U.S. EPA has not formally classified perchloroethylene in Category B2 as a "probable human carcinogen." IARC has
classified perchloroethylene in Group 2B as a substance considered "possibly carcinogenic to humans.'

c The U.S. EPA has classified methylene chloride in Category 82 as a "probable human carcinogen,1 while IARC has
classified methylene chloride in Group 2B as a substance considered "possibly carcinogenic to humans.'

Source:  UNEP (1989).
                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                                          3-38

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                                 Table 7/7-9
                    PROPERTIES OF KETONES
KETONE
Acetone
Methyl Ethyl Ketone (MEK)
Diethyl Ketone
Methyl n-Propyl Ketone .
Cyclohexanone
Methyl Isobutyl Ketone
(MIBK)
Methyl n-Butyl Ketone
Methyl Cyclohexanone
Acetonyl Acetone
Diisopropyl Ketone
Methyl n-Amyl Ketone
Diacetone
Formula
C2H6CO
C3H8CO
C4H10CO
C4H10CO
C5H10CO
C5H,2CO
C7H12CO
C6H12CO
C,H10(CO)2
C6H14CO
C6HUCO
C6H12CO
Mol. Wt.
58.08
72.10
86.13
86.13
98.14
100.16
100.16
112.17
114.14
114.18
114.18
116.16
Ibs
per gal
6.58
6.71
6.80
6.72
7.88
6.68
6.83
7.67
8.10
6.73
6.81
7.82
B.P.
°C
56-57
79-81
100-104
101-107
130-172
112-118
114-137
114-173
185-195
114-127
147-154
130-180
Flash
Point
°C
open cup
-17
-2.2
12.6
7.2
62
17.6
22.5
47.3
78
23.6
48.4
8.8
Evap Rate
CCI4=100
139
97
-
66
12
47
32'
7
- •
-
15
4
Solubility
Parameter
- H
9.9
9.3
8.8
8.7
9.9
8.4
8.3
9.3
-
8.0
8.5
- -
Surface
Tension
20°C
Dynes/cm
23.7
24.6
24.8
25.2
-
22.7
25.5
-
39.6
-
-
29.8
Source: DuPont, A.F. Barton, Handbook of Solubility Parameters and Other Cohesion Parameters, CRC Press
                * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT.*
                                    3-39

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(see the section on supercritical fluids).  Primary considerations for
choosing pressurized gases depend on the  following properties:

   •  Surface chemistry.  This factor is  ultimately responsible for the nature
      of the electrostatic forces between surfaces.

   •  Porosity.  Porous (and rough) surfaces possess the potential to
      mechanically lock contaminant and substrate and further hinder the
      cleaning process.

   •  Roughness of surface.  Large.particles on a smooth surface may be
      removed more easily than small particles on a rough surface for the  same
      reason.

   •  Size, shape, and homogeneity of the contaminant.  On a microscopic
      level, all surfaces possess ridges  and valleys that make intimate
      contact between surfaces difficult.  Adsorbed contamination on particles
      and other surfaces also hinders contact and prevents relatively short-
      range molecular interactions from occurring.

   •  Sensitivity of the surrounding area to ejected material.  Relatively
      inert gases and mixtures are most often used with specially designed
      equipment to meet the cleanliness requirements of the surrounding area.

      Depending upon which pressurized gas is used in the cleaning
application, the advantages of using pressurized gases versus halogenated
solvent cleaning could include the following:

            Low viscosity
            Low toxicity
            High diffusivity
            Nonf1ammabi1ity
            Low capital cost.

The disadvantages of using pressurized gases could include:

            Low density
            High pressure (rupturing of seal)
            Cleaning of critical components
            Often not effective for microscopic particles
           • Safety considerations.  •

Possible Gases:

      Gases which may be used include.air, rare gases, carbon dioxide,
chlorodifluoromethane (HCFC-22), and nitrogen.  These gases are readily
available in bulk and smaller quantities  and in numerous grades of purity.
These gases may be stored at room temperature.  Dry air is produced from
ordinary air by removing hydrocarbons by  oxidation.  Carbon dioxide is then
removed and the air is compressed and dried.

      Because of its oxygen content, air  reacts with many substances, rare
'earth gases, however, are noted for their extreme chemical inactivity.  These
monatomic gases are helium, neon, argon,  krypton, and xenon and may be
obtained by fractionation of liquid air.  Argon, the most abundant of the  rare


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 earth  gases,  is  commercially available in cylinders ranging from 1,775 to
 6,000  psig at 21.1°C.   Argon is not toxic,  but is an asphyxiant and is heavier
 than air.

       Carbon dioxide,  which is recovered from a number of processes,  is
 colourless,  odourless,  nonflammable,  and slightly acidic.   .The gas is stable
 under  most conditions,  but it will dissociate into carbon dioxide and carbon
 monoxide  in the  presence of free carbon at high temperatures.   For example,  at
 100°C,  the equilibrium ratio of carbon dioxide to carbon monoxide is  0.7
 percent to 99.3  percent.   Above the critical temperature of 31°C,  all solid
 carbon dioxide converts to a gas.   It may be shipped under its own vapour
 pressure  of 830  psig at 21.1°C.   Caution must be taken in dealing with carbon
 dioxide since it acts'as an asphyxiant and cumulative amounts  of the  gas can
 act like  a poison.   Note that the use of carbon dioxide does not contribute to
 global warming because the source of the most carbon dioxide is the air
 itself.                         .                  .

       Colourless and nonflammable, HCFC-22 has an ozone-depletion potential of
 0.05.   At high temperatures, various metals may catalyze decomposition of the
 gas.   Silver, brass,  bronze, aluminum, ,1340 steel, copper,-nickel, 18-8
 stainless steel, and inconel react in descending order, with silver being the
 most reactive.  Magnesium and aluminum alloys with two percent or more
 magnesium are particularly reactive in the presence of water.   Natural rubber
 may also  be swollen and degraded by the solvent.  Continued flooding of
 localized areas  with liquid produces rapid chilling.  This feature may be
 desirable to remove more tenacious contaminants.  It is often shipped as a
 liquified gas under its own pressure of 123 psig at 2.1.1°C.   The gas  is
 available in bulk and small disposable cans.  Direct contact wi-th liquid
.chlorodifluoromethane may cause frostbite.   The gas is considered to be
 nontoxic,  but high concentrations can produce dizziness, narcosis, and nausea.

 Equipment Considerations:    •                           •

       Clean dry  air may be economically produced from pressurized air in-
 house. Specifically designed diaphragm and other noncontaminating pumps are
 available.  High efficiency filters,  drying agents, arid other  equipment can be
 used for  most of these gases.

       A problem  inherent in cleaning with high pressure gases  is the
 development of static charges.  Ionizing guns that can alleviate this problem
 are available from clean room equipment suppliers.

       Typically, clean, dry, inert gas, or air is fed to a pressurized gas gun
 at 689.5  kPa. Many models offer 0.3 to 0.5 micron particle filtration with a
 maximum outlet pressure of ionized gas at 207 kPa.  Different ionizing and
 filtration techniques have been designed for specific needs.  One model is
 reported  to remove 3.0 micron size particles with 99 percent efficiency from
 bare silicon wafers.

       Composition of the contaminant and substrate may determine whether or
 not ejected material produced by pressurized gas will damage surrounding
 surfaces.   Metal dust may be easily removed from an assembly with pressurized
 gas.   However, if an optical component with a sensitive coating is part of the
 assembly,  it could be scratched by impinging particles.  Particles 'With low
 mass may  not present a problem.  Likewise, harder components may be resistant


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                 '      ,               3-41

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 enough to  allow this  process.   Consideration of dislodged particles is not
 limited to resistance of the assembly or part because, clean room requirements,
 as  well as surrounding structure,  may not tolerate increased levels of
 contamination.

       Containment of  ejected debris may be accomplished for small parts by
 operating  the  process in a laminar flow work station equipped with a high
 efficiency particulate air filter  or an ultra-low penetration air filter.
 Vacuum may also be used with pressurized gas on some parts to capture
 dislodged  contamination.

       3.3.11       Supercritical Fluids

       The  use  of supercritical fluids (SCF) ,  especially carbon dioxide, has
 escalated  in the early 1990' s.   SCFs are chemicals that 'are normally liquid or
 gaseous at standard temperature and pressure.   However,  when the pressure and
 temperature are increased to specific levels,  the chemical reaches a
 supercritical  state and exhibits very different solvent properties.  Table
 111-10 lists some of  the data for  typical supercritical solvents.

       In the case of  supercritical carbon dioxide (C02) ,  the  fluid has  been
 used for many  years in the food and flavour  industry.   One example is the use
 of  supercritical C02  to  decaf feinate  coffee.   The  properties  of  the SCFs  are
 such that  at each temperature and  pressure combination within the
 supercritical  region,  the fluid behaves with slightly different  solvency
 powers.  In the coffee -decaf feination example cited above, the coffee beans
 are loaded into a very large,  high pressure  reactor.   The C02 is  injected into
 the reactor and the pressure and temperature are simultaneously  increased.
 The coffee bean flavour — an organic chemical itself — is first  removed from
 the beans  by adjusting the pressure and temperature and then releasing the
 carbon dioxide to a capture chamber,  where the flavour is held.   Then,  the
 reactor is refilled with C02, and  adjusted to  a  different temperature  and
 pressure and the caffeine is removed and captured' into another holding
.chamber.   Finally,  the pressure -and temperature combination of the coffee
 flavour is readjusted and the flavour is added back to the beans.

       The  equipment for a supercritical C02 cleaning  system can  start  at
 between $60,000 to $120,000 for small reactors of approximately  1 cubic foot
 capacity.   The cost of the unit depends on the types of soil  to  be removed and
 the size of the high-pressure reactor.   It is common for the  reactors to be
 operated in the 2000  to 5000 psi range with  temperatures between 40°C to
      Compared  to  liquid solvents  such as  CFC-113  and 1 , 1 , 1-trichloroethane ,
SCFs have a higher diffusivity  and a much  lower  density and viscosity.   This
combination of  characteristics  allows for  rapid  extraction of contaminants and
phase separation.   Other chemicals,  such as  nitrous  oxide,  ethane,  ethylene,
and water, can  be  used  in supercritical cleaning processes,  but C02 has  proven
to be the safest,  the most abundant and economical,  and very effective.
Supercritical fluids display  the following properties:

      •     wide range  of solvent  solubilities
      •     gas -like diffusivity
      •     zero surface tension"
                    * 1994 UHEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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Table 777-70
DATA FOR TYPICAL SUPERCRITICAL SOLVENTS

Solvent
Methane
Ethylene
Chlorotrifluoromethane
Carbon dioxide
Ethane
Nitrous oxide
Sulfur hexafluoride
Propylene
Propane
Ammonia
Trichlorpfluoromethane
n-Hexane
Isopropanol
Ethanol
Toluene
Water
Critical
Temperature
fdee. Q
-83
9
29
31
32
36
45
92
97
132
198
234
235
243
.318
374
Critical
Pressure
fatm)
45.4
49.7
38.7
72.8
48.2
71.5
37.1
45.6
. 41.9
111.3
43.5
29.3
47.0
63.0
40.6
217.7

Density
0.16
0.22
0.58
0.47
0.20
0.45,
- 0.74
0.23
0.22
0.24
0.55
0.23
0.27
0.28
0.29
0.32
1994 UNEP  SOLVENTS, COATINGS,  AND ADHESIVES REPORT *
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      •     short process times
      •     low energy costs
      •     does not generate waste products  (except for  the  contamination
            removed)
      •     gas is completely recoverable

      SCFs exhibit many properties of an ideal process, however  the high  cost
of the equipment and the necessary process development  to fine-tune the
cleaning process will require significant funding.  Some  characteristics  of
the SCF process that should be considered include potential material
compatibility problems and the necessary training for operators  of the high-
pressure equipment.  SCF processes should be  targeted to  industries where
expensive fluids are to be removed from precision hardware, specifically  the
medical, space, and defense industries.

      Test results obtained by one company using SCF cleaning for
developmental tests on precision gyroscopes for high-reliability use  indicate
the following:

      •     effective removal of oils and polyhalogenated fluids
      •     pressures and temperatures required
            -- perfluoropolyether oils  ... 1500 psi, 170  °F
            -- halogenated and other oils  ... 3500 psi, 185 °F
      •     incompatible with hermetically sealed devices
      •     epoxy weight gains detected of greater than 2.5 percent
      •     effective for deep pores (width/diameter of 650 to 10,000)
      •     material compatibilities
            -- metals, ceramics, and glass were good.
            -- thermoset plastics were good
            —thermoplastics were fair to good
            -- elastomers (rubber) were bad,  except for silicones

      Supercritical carbon dioxide has been tested by several users as a
potential replacement for precision cleaning  with CFC-113 and 1,1,1-
trichloroethane.  Table III-11 illustrates the types of applications  that have
been successful.  It is important to confirm  that the cleanliness achieved in
each application matches the precision cleaning requirements.

Process Overview:

      Figure III-6 shows a generic supercritical carbon dioxide  cleaning
process.  Carbon dioxide is pressurized and heated to its supercritical state
and introduced into the 'extraction vessel at  the selected extractor operating
conditions.  In the extractor, the supercritical fluid  selectively extracts
one or more components from the source material. The solute-'rich gas  exits the
extractor and undergoes a temperature and/or  pressure change.  This change
decreases the solubility of the solute in the fluid and,  due  to  the change in
solubility, a solute/fluid separation takes place in the  separator vessel.

      In order to determine whether SCF is a  technically  feasible and
economically viable alternative, it is necessary to evaluate,  phase equilibrium
properties of the fluids.  These include the  number of  phases present, the
composition and density of each phase, and the equilibrium changes associated
with temperature, pressure, and composition.  This is important  because of the
often complex behaviour of fluids in high-pressure phase.  Phase equilibrium


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                           Table III-ll
    SUPERCRITICAL CARBON DIOXIDE APPLICATIONS
Hardware

Spacecraft



Radar



Laser


Gas system


Cleaning aid



Nuclear

Missiles
Materials/Components Cleaned  Contaminants Removed
High voltage cables
Bearings
Rivets

Connectors
Transformers
Cables

Optical benches
O-rings

Seals
Cotton ball/wipers
Cotton tipped applicators
Valves

Gyroscopes
Silicone oils
Lubricants
Flux residues
Dielectric oils.
Machine oils
Plasticizers

Plasticizers
Monomers

Organic extractables
Triglycerides
Adhesive residues

Radioactive Oil

Perfluoropolyethers
             * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                            Figure III-6

        BASIC MODEL DESIGN FOR CARBON DIOXIDE
             SUPERCRITICAL CLEANING SYSTEM
   Pressure Regulator

                   Pumpl
                   Pump 2
            Conditioner
Carbon Dioxide
 Gas Supply
    High Pressure
    Vessel
Gauge
              \
                                                           Exhaust
                                                    Separator
Source: Jackson 1987
                                                             I1M06-S1
              * 1994 UHEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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and mass transport data is used to size equipment, determine utility
requirements, and estimate costs.

      The pressure-dependent dissolving power of C02 is not limited to
polymers and oils of only medium molecular weight and materials of low
polarity.  Very highly polar materials such as alcohols and organic acids  are
soluble, and among polymeric materials, many polymers and high molecular
weight oils, such as silicones and fluoroethers, commonly associated with
gyroscopes are soluble; silicones of several hundred thousand MW dissolve  to
high levels in supercritical C02.   For completeness here,  SC C02 can dissolve
many hydrocarbons, esters, silicones, perfluorinated oils, halocarbon-
substituted triazines, and polychloro- and bromo-tri'fluoroethylene; these
materials can also be fractionated based on molecular weight which has  special
purpose application in lubrication and coating.  While there are polymers  that
are insoluble in CC>2,  some of them — depending on the degree of cross-linking
and crystallinity - may exhibit swelling and/or incompatibility in C02.

      Unfortunately, there are also many confusing claims which continue to be
perpetuated throughout the literature and patents regarding the ability of SC
C02 to dissolve particulates (e.g.,  lint,  dust,  scale,  metal,  and salts,
etc.), fluxes, and other materials.  While it is possible that some dislodging
of particulates can occur due to'velocity forces, they do riot dissolve-in  C02.
Based on extensive investigation with rosin-based fluxes, it can be stated
with certainty that these materials are insoluble in carbon dioxide.  Some of
the confusion may arise because of incompletely understood phenomena.   For
example, abietic acid (the main component of rosin) is soluble in C02 and  it
is interesting that a recent international patent application has stated that
abietic acid must be modified/with methanol to impart any reasonable  v
solubility in C02.  The confusion arises because after exposure t,o high
temperatures required for reflowing solder flux, abietic acid can polymerize
enough to render the flux residue insoluble.  Even many low solids and  water
soluble fluxes are insoluble in C02",  thus SC C02  is  not generally applicable
to circuit board cleaning (although in special cases it may show limited
results.)

      3.3.12    .  Plasma Cleaning                      .

      A plasma is an electrically charged gas containing, ionized atoms,
electrons, highly reactive free radicals, and electrically neutral species.
Plasma, produced by passing an electric current through a process gas,  is
characterized by high reactivity and a specific frequency of electromagnetic
radiation, usually in the UV and visual light bands.  Common examples of
plasma are fluorescent lighting, neon signs, and the solar corona.

      Plasmas can exist in a wide variety of pressure and temperature
conditions, but "cold" plasmas are best for cleaning applications.  These
typically have temperatures under 60°C.  Normal operating pressures are 1-5
mmHg, under an atmospheric pressure of 760 mmHg.  Such operating conditions
are easily produced.
                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
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      The cleaning process consists of six steps:

      •     Evacuating the chamber to base vacuum pressure

      •     Introducing process gases and then stabilizing them at  operational
            pressure

      •     Irradiating the chamber with radio frequency energy to  produce  the
            plasma --a step that causes the process gas to flow  through  the
            chamber removing compounds such as carbon monoxide, carbon
            dioxide, and water vapour

      •     Shutting off radio frequency energy and process gases and
            returning to base pressure

      •     Purging the chamber with a nonreactive gas such as nitrogen to
            remove all traces of volatile compounds

      «     Returning to atmospheric pressure and then venting to atmosphere.

      The third step is the actual cleaning portion of the procedure.  The
ipns and electrons in the plasma are energized by the radio frequency
radiation to energy levels of approximately 1 eV.  The bonds found  in organic
contaminants, C-C,. C-H, and C-0, have energies from 3 to 5 eV.  The high
reactivity of the ions, combined with their kinetic energies, is  sufficient to
break these organic bonds.  The ions then react with the freed atomic
components and form volatile compounds which are then removed by  the flow of
the process gas.

      The advantages of plasma cleaning include:

      ••     Process gases are relatively cheap, nontoxic, and noncaustic.
            Example gases are oxygen,  argon, helium, silicon tetrafluoride,
            and air.

      «     Only small amounts of process gas are required for each cleaning.
            This amount will vary with exposure time and size of  enclosure.

      •     Low operating costs compared to solvent cleaning.  No disposal
            procedures are necessary.

      •     The cleaning time depends greatly on the specific process, but
            generally ranges from a few seconds to a few hours.

      «     Because the plasma is essentially gas-like, all shaped parts  are
            cleaned simultaneously and evenly.  Because the cleaning takes
            place, on the molecular level, all features, regardless of size,
            are cleaned equally well.

      The.disadvantages of plasma cleaning include:

      •     Capital costs are initially high and the equipment is highly
            specialized.  Reactor costs are typically $20,000 to  $130,000.
                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
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      •     For  space  systems  such  as  satellite  optical  components  that must
            be cleaned during  use,  the plasma  gases  must be  provided at launch
            or produced chemically.

      •  .   Contaminant layers are  not cleaned at  an even rate.   It may be
            -difficult-to determine  exactly how long  the  process  should last.
            Outer  layers are stripped  faster,  and  at lower energies,  than
            layers close to the original  surface.  A possible  reason for this
            could be  that the  inner layers are exposed to more UV radiation
            from the plasma itself,  and therefore  cross-polymerize  and form
            stronger bonds with the surface.   For  space  systems,  this
            uncertainty could  lead  to  overuse  of limited process  gas  supplies.

      •     Plasma is  not formed efficiently in  hidden areas of  complex parts
            and  diffusion of plasma into  these areas is  slow.

      •     Using  oxygen as a  process  gas produces a visible film on the
            surface of gold mirrors.   Such a film may be difficult  to remove
            and, if left on the mirror, may increase light scattering.

      •     The  energy of the  process  must be  limited to avoid sputtering,  a
           •- phenomenon that can damage the elements  being cleaned.  .

      •     Because cleaning capacity  is  low,  gross  contamination should be
            removed prior to plasma cleaning.

      •   .  Operator training  will  be  required.

      A plasma cleaning system usually consists  of a reactor,  a  radio-
frequency generator, and a control  system.  The  reactor,  which can  be
cylindrical or planar,  must hold the components  for  cleaning.  The  radio-
frequency generator supplies the energy for creating plasma.   The control
equipment governs  the  composition of the  reagent gas, the flow-rate of the
reagent gas, the radio-frequency power, the reactor.'s operating pressure, and,
the processing time.

      Several gases possess desirable  characteristics for plasma  cleaning.
The specific gas would be determined by the application.   An important point
to concede is that some  surfaces react with some gases directly,  a  reaction
which could actually cause further  contamination.

      A readily  available, process gas  is  necessary.   Producing such gases in
restricted space may be  difficult.  Most current  cleaning technologies are
batch processes.  Further design would be necessary  to make plasma  cleaning a
viable line procedure.   Once-cleaned,  precautions must be taken  to  prevent
recontamination.  Slight exposure to plastics  or other organic substances may
allow thin layers of organic compounds to adhere to  hyperclean surfaces.  This
is an important  consideration  -for precision cleaning operations.  '

      Plasma has been  used in  several  different  applications for  removing (1)
organic contamination  and residue from substrates, (2) residue from plating
baths and washing solutions, (3)  conformal coating to repai'r circuits,  and  (4)
epoxy markings and light oil on automotive bumpers.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      3.3.13      Ultraviolet Light/Ozone Cleaning Method             *

      The UV/ozone cleaning process has been used successfully to remove thin
organic films from a number of different surfaces, including glass, quartz,
mica, sapphire, ceramics, metals, silicon, gallium arsenide, and polyamide
cement.              .

      UV/ozone cleaning is a simple process which is relatively inexpensive to
set up and operate.  Under the proper conditions, the process can produce
clean surfaces in less than one minute, and these will remain clean
indefinitely during storage under UV/ozone.

  '    The basic UV/ozone cleaning process involves the exposure of a
contaminated surface to UV light in the presence of ozone.  The cleaning
occurs as a result of various photosensitized oxidation-processes.
Contaminant molecules are excited and/or dissociated by the absorption of
short-length UV light.  These molecules, and the free radicals produced by
dissociation, react with atomic oxygen to form simpler, volatile molecules
such as carbon dioxide, water vapour, and nitrogen.  This reaction removes the
surface contamination.

      There are several variables in the UV/ozone process that determine the
effectiveness of the cleaning.  These include the following:  contaminants
present, precleaning procedure, UV wavelengths emitted, distance and
atmosphere between the UV source and the surface to be cleaned, contact angle
of the light, and length of time of the exposure..

      Testing must be performed to determine optimal orientations for
different contaminants and surfaces to be cleaned.  Surfaces that have
multiple contaminants, or thick layers of contaminants, require precleaning in
order for the UV/ozone process to work.  UV/ozone will efficiently clean
organic contamination, but particles and inorganic components are more •
difficult to remove with this process.  To maximize the rate of cleaning, the
part being cleaned should be kept as close as practicable to the UV light
source.

      Because the UV/ozone process requires no moving parts, it is easy to
maintain and operate.  However, both the use of UV light and the presence of
excessive ozone can be dangerous to humarjs.  UV light can cause eye injuries
and ozone causes respiratory damage.  The low workplace limits for ozone (0.1
ppm) require special design considerations.

      The UV/ozone process may also cause damage to the surface being  cleaned.
Staining and discoloration of materials can result from improper wavelengths
and exposure times.  Overexposure of materials to UV light can also cause
corrosion.  One positive side effect of the UV/ozone process is the
neutralization of static charges on insulator surfaces.

Possible Applications:

      The UV/ozone cleaning process has numerous applications.  The primary
use is substrate cleaning prior to thin film deposition, such as  is necessary
in the production of quartz crystal resonators.  The process is also used for
cleaning and storage of metal tools, masks, resonator parts, and  storage
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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containers.  UV/ozone can be used in a hermetic sealing process that adheres
to clean surfaces in an ultra-high vacuum.

      Other applications which have been identified include:  photoresist
removal, the cleaning of vacuum chamber walls, photomasks, silicon wafers,
lenses, mirrors, solar panels, complex configured beryllium gyroscope and
accelerometer components, and gallium-arsenide wafers.

      Future developments in UV/ozone .cleaning procedures will come from
further testing and experimentation with specific applications.  Cleaning
techniques need to be refined considerably before this method of cleaning will
receive widespread acceptance.  The technology advances in plasma cleaning and
supercritical fluids may reduce the attention that UV/ozone cleaning will
receive, except for use in special medical applications.
3.4   ENVIRONMENTAL-AND ENERGY CONSIDERATION

      Two major factors in determining the feasibility of any proposed
alternative to CFC-113 or 1,1,1-trichloroethane are the environmental impacts
and the energy requirements of the substitute.  The wide variety of
alternative processes available carry with them an equally wide variety of
environmental and energy considerations.

      Conservation and recovery procedures have proven to be effective in
reducing the environmental impacts of industrial solvent usage.  These
procedures are extremely valuable, not~only in cases where acceptable
alternatives to CFC-113 and 1,1,1-trichloroethane have not yet been found, but
also .where organic solvents used in the system vaporize.  Currently, though
solvent can be recycled, the  recycled solvent is rarely used in precision
cleaning applications due to  its perceived impurities.  The solution to this
problem is the individual recovery and handling of any solvents in use at a
given location.  Careful handling will help prevent the mixing of solvents,
thereby allowing for treatment and potential reuse..  Additionally, companies
may purchase small inexpensive solvent reclamation equipment to,offset the
high costs of solvent disposal.

      Several of the alternatives presented in this chapter require wastewater
treatment.  These alternatives are the aqueous and semi-aqueous cleaning
processes.  In both cases, the treatment of the wastewater can often be
performed in-house so that the water may be recycled.

      The ozone-depletion potential (OOP) associated with alternative
processes is an- extremely important environmental consideration.  HCFC
solvents have small, but significant, ODPs which may limit their use.         ;
Conversely, the ODP of zero associated with alcohols/perfluorocarbons as well
as with perfluoroalkanes make them more attractive alternatives.  It should be-
no ted, however, that while these two alternatives have an ODP of zero, they
both have relatively high greenhouse-warming potential.

      Manufacturers of chemical solvents and their HCFC alternative financed .a
study of the "Total Equivalent Warming Impacts•(TEWI)" of the phase out of
                    •* 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     3-51

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CFC-113.10  TEWI includes the direct effects of emissions of greenhouse gas
solvents plus the  indirect effects  of  energy  required  for  supply,  operation,
and disposal of waste.   The  analysis aims  to  include every direct  and indirect
effect so that alternatives  can be  compared for  environmental  acceptability.
A summary is presented  in Appendix  I.

      Another important consideration  of alternatives  to CFC-113 and 1,1,1-
trichloroethane in precision cleaning  applications  is  the  possible health
effect on workers  and the general population.  Each alternative has
occupational hazards associated  with  its  use.   For example, aliphatic
hydrocarbons are flammable,  UV/ozone emits  harmful  wavelengths of  radiation
and produces noxious gas, some gases are asphyxiants,  and  most chlorinated
solvents are considered potentially carcinogenic.

      While energy considerations are  also  important in  the choice of an
alternative precision cleaning method,  they usually fall behind environmental
impacts in their importance.  One case where  energy is of  major concern is in
the plasma cleaning process.  In this  case, it is a necessity  that the process
energy be limited  to a  given level  so  that  the cleaning  can be properly
performed,

      In many of the other processes,  the  major  energy consideration is the
amount which is consumed in  completing the  cleaning process.  Extremely high
energy utilization will obviously increase  the,operating costs.
3.5   POTENTIAL GLOBAL REDUCTION OF CFC-113 AND  1.1.1-TRICHLOROETHANE  IN
      PRECISION CLEANING APPLICATIONS

      In the first release of this document in 1991,  this section was  written
with the hope that the consortium of academia, industry, and government,  could
work together to develop alternatives  to ozone depleting solvents in precision
cleaning.  .In the 1991 version of this document  all of the alternatives that .
are known in late 1994 were known then.  However,  in  1994 the  industries  that
were large consumers of ODS have reduced their consumption to  approximately
one-third of their 1988 usage.

      Several of the technologies that were relatively new in  1991 have become
more sophisticated in recent years.  Supercritical fluid cleaning now  has  its
own society, the Joint Association for .the Advancement of Supercritical fluid
Technology (JAAST), which is developing and promoting the use  of supercritical
C02 for high reliability-cleaning in various applications in the space and
defense industry.  Semi-aqueous cleaning systems have passed numerous  tests
and were first used on satellites in 1992.  Gas  plasma cleaning applications
have grown significantly.  Organic solvents -have progressed from the highly
     10  AFEAS  member companies include Akzo Chemicals BV (The Netherlands),
Allied-Signal, Inc.  (U.S.), Asahi Glass Co., Ltd.  (Japan), Atochem  (France),
Daikin Industries, Ltd.  (Japan), E.I.  DuPont De Nemours & Co.  (U.S.), Hoechst
(Germany), ICI Chemicals and  Polymers, Ltd.  (U.K.),  Kali-Chemie AG  (Germany),
LaRoche Chemicals, Inc.  (U.S.), Montefluous  S.p.A.  (Italy),  and Rhone Poulenc
Chemicals/ISC Division  (U.K.).  The report, produced by Arthur D. Little, is
titled Comparison of Global Warming Implications of  Cleaning Technologies
Using a Systems Approach.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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volatile single-component aliphatics  (still  preferable in some instances) to
blends that offer multiple properties.   Finally,  the PFCs and continuing
research on hydrofluorocarbons  (HFCs)  is moving forward,  and new equipment has
been manufactured to help reduce  the  environmental impact of these new
solvents.             ,

      Conservation and recovery,  a common theme in 1991,  has become
commonplace in developed countries.   Companies in these countries that are
still using ODS solvents have incorporated sliding covers, turn off their
heaters at night, and train  their workers in proper vapour degreaser
operation.  By January 1, 1996, the majority of companies in the United States
and other industrialised countries, will have met their goal of finding and
implementing more environmentally sound cleaning processes.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                                   CHAPTER 4

                         •  METAL CLEANING APPLICATIONS
4.1    BACKGROUND
                           i
      Metal cleaning applications  include all applications  in which metal
parts are cleaned during manufacturing or maintenance except for  those metal
parts that are included in precision cleaning applications.1

Primary Production                   .    .

      Metal cleaning can be divided conveniently  into 3 main sub-divisions:

      •     Primary production
      •     Periodic maintenance
      •  .   Repair and service                                    .

Some of the processes which precede metal cleaning  include:  guillotining
stock material, numerically controlled machining  from solids, multistage deep
drawing, stamping, forging, casting (of all technologies),  rolling, extruding,
injection moulding, non-destructive testing, welding, and .vacuum  forming from
sheet spinning.  The materials which are cleaned  in primary procedures
include:  ferrous metals and alloys; aluminium, titanium, and other light
metal alloys; zinc based die cast; other nonferrous metals  (e.g., copper and
alloys); moulded polypropylene and other thermoplastic materials; carbon fibre
reinforced epoxy, glass fibre reinforced epoxy, and other composite materials;.
and high alumina ceramics.                .          .    .

      Finally, the following are examples of processes which follow primary
metal cleaning.  These procedures  include electrolytic surface treatment,
painting and application of other  coatings, chemical vapour deposition, radio
frequency coating, fluid bed coating with polymers, applications  of adhesives
prior to bonding, galvanizing, simple surface cleaning prior to rework,
repair,  storage or subsequent assembly, and application of  temporary
protective materials for storage and delivery protection.

Periodic Maintenance

      There are many industrial processes in which  plant and machinery are
routinely and regularly disassembled, cleaned, reassembled, and refitted with
functional materials.  This can occur at the end  of a working interval (end of
     • 1  See Chapter 3.  Delicate and intricate metal parts that, must be cleaned
to a degree of. micrometer fineness are considered precision  cleaning
applications in this report.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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shift for example) or at fixed intervals.  Many of these require the use of
solvents, including CFC-113 and 1,1,1-trichloroethane.  Examples include:

      •     Heating, ventilation and air conditioning systems and equipment
      •     Metal working machinery and equipment
      •     Hydraulic equipment and systems
      •     Adhesive spreading machinery (for impact adhesives, adhesives
            based on polychloroprene), epoxy resins, hot metal systems, etc.
      •     Silk screen stencils for general printing, solder past printing,
            etc.
      •     Instrument pressurized oil filling rigs using Krytox fluorolube
            and silicone oils
      •     Polymer forming equipment -- injection moulding, blow moulding  --
            vacuum moulding, etc.
      •     Conventional hydrocarbon oil-fill rigs -- transformers,
            transmission systems -- engines, etc.
      •     Copiers and laser printing machines
      •     Newsprint printing machines
      •     Offset printing machines
      •     Tooling

Repair and Maintenance

      This is possibly the most widespread and diverse subdivision of metal
cleaning and covers, for the most part, "cold solvent cleaning" in which
1,1,1-trichloroethane has become the most important'cleaning agent in recent
years.                                                '

      To list examples would be to list most mechanical artifacts of the
modern world; however, general areas are:

      •   .  Primary power sources

                  auto engines and power trains      •
                  truck diesel engines and transmission
                  marine diesels, auxiliary deck power sources
            --    locomotive diesels and electric motors
                  aircraft gas turbines and auxiliary power generators

      •     Industrial handling equipment

                  conveyor systems
                  cranes and derricks
                  mobile, overhead hoists
                  fork lift trucks

      •     Metal working machinery -- machine tools, press-tools, forging  --
            deep drawing, etc.

      •     Sport and leisure

                  bicycles
                  boats
            --'    outboard motors
                  cars


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                   cameras
                   video  recorders
                   television and radio

       1,1,1-Trichloroethane  is  used extensively in metal cleaning.   Worldwide
production in  1990 amounted  to  about 726,000 metric tonnes  with 66  percent of
this  total used for metal  and precision cleaning.   CFC-113  use in metal
cleaning is considerably less than 25 percent of that  of 1,1,1-
trichloroethane.   This chapter  describes a number of alternative materials and
processes  that clean metals  effectively,  including solvent  blends,  aqueous
cleaners,  emulsion cleaners,  mechanical cleaning,  thermal vacuum deoiling,
and no-clean alternatives.
4.2    CFC-113  and 1.1.1-TRICHLOROETHANE USE IN METAL CLEANING APPLICATIONS

       4.2.1  Metal Cleaning Applications

       Metal  cleaning is  a surface  preparation process that removes'organic
compounds  such as oils and greases,  particulate matter,  and inorganic  soils
from metal surfaces.  Metal cleaning prepares parts  for  subsequent  operations
.such as  further machining and fabrication,  electroplating,  painting,  coating,
inspection,  assembly,  or packaging.   Parts  may be  cleaned multiple  times
during the manufacturing process..

       Metal  cleaning usually is  done' on flat or formed sheet metal  or  on
milled and machined  metal stock.   Tubing, engine-parts,  motors,  nuts,  bolts,
screws,  honeycomb structures,  and  rivets are other common configurations.
Machined parts tend  to have complex  and curved surfaces  with holes  and pockets
that can trap  both particulate matter and liquids.   In large facilities,  a *
wide spectrum  of metals  and alloys may require cleaning  using the same
cleaning system.   For. example, the U.S.  Air Force  at one location cleans  15
metal  alloys during  aircraft maintenance operations  (Bellar 1988).  Metal
cleaning also  involves the cleaning  and preparation  of moulds used  to  cast
metal  parts, varieties of plastics,  and composite, materials.

       4.2.2  Metal Cleaning Solvents

       Traditionally,  chlorinated solvents such as  trichloroethylene (TCE),
1,1,1-trichloroethane  (TCA),  perchloroethylene (PCE),  and methylene chloride
(MC) were  used for metal degreasing  (ICF 1988).   1,1,1-Trichloroethane began
to be  substituted for  TCE as a metal cleaner in the  1960s;  its use, however,
increased  dramatically because,  of all the  chlorinated solvents,  1,1,1-
trichloroethane has  relatively low toxicity,.high  solvency, low surface
tension, and optimum boiling temperature for vapour  degreasing.   CFC-113  use
for metal  cleaning began in the  1970s as concerns  increased about the  toxicity
and effects  .of long-term,  low-concentration exposure to  some chlorinated
solvents.  In  the United States, the use of CFC-113  as a metal cleaner
doubled  from 1974 to 1983,  from  an estimated 26,000  metric tons to  52,000
metric tons.               '              •
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      4.2.3  Metal Cleaning Processes

      4.2.3.1  Cold Immersion Cleaning

      The most common method of cleaning with ambient temperature solvents  is
immersion cleaning.  Most operations are fairly simple and use halogenated
solvents, organic solvents, or blends near room temperature.  The basic
technique involves immersing or dipping a part by manually, mechanically, or
hydraulically lowering the part into a tank containing solvent.  While the
simplest immersion cleaning method  (application) is  soaking the article  in
solvent most soils even if solvent- soluble, require agitation for adequate
cleaning.  Therefore, immersion/dip cleaning usually is used in conjunction
with other operations such as mechanical agitation or ultrasonic cleaning.
Immersion cleaning also may be used to remove heavy soils prior to manual
cleaning or vapour degreasing.  Solvent use in immersion cleaning is
relatively high because of drag-out and because there is frequently no vapour
level control (condenser, cooling coils) on the equipment.

      Mechanical- agitation allows nonsoluble particles to be stripped away
from the parts, thus producing cleaner parts than a simple dip tank.
Mechanical agitation is produced by moving the solvent within the bath or the
metal part.  The solvent can be agitated mechanically with a motor-driven
propeller or a circulating pump, or can be ultrasonically agita'ted using
transducers and an ultrasonic generator.  Parts can be agitated by placing
them on an agitation platform.  Air-agitated dip tanks also improve cleaning
efficiency by helping to remove nonsoluble soils, but because this process
greatly increases solvent loss by increasing the evaporation losses and might,
where relevant, increase concern about the evaporation rate of volatile
organic compound (VOC) emissions, it is not a viable option for cleaning
enhancement.       ..

      Small containers may be used  for maintenance cleaning of electronic .
parts; large containers may be used for cleaning .lar^e machined parts or  large
volumes of.smaller parts in baskets (ICF 1989).  Even if the immersion tanks
are small, there are often many cleaning stations and the solvent may be
changed frequently - - all of which  provide additional reasons why cold
immersion cleaning uses a relatively large volume of solvent-.  While many
container sizes exist, a typical container (tank) size is about 30 centimetres
by 60 centimetres, containing solvent to a depth of 75 centimetres; the
working volume of solvent ranges from about 50 to 400 litres (ICF 1989).
Tanks are often fitted with recirculation pumps to flush parts.  Particulate
filters and stills are integrated in some units to maintain solvent quality.

      4.2.3.2  Vapour/Hot Liquid Cleaning

      Vapour degreasing is a process that uses the hot vapour of a solvent  to
remove soils, oils, greases, and waxes.  A basic vapour degreaser .unit is an
open-top steel tank with a heat source at the bottom to boil the solvent  and a
cooling zone near the top to condense the solvent vapours.  The vapours
displace the lighter air and form a vapour zone above the boiling solvent.
The hot vapour is condensed when it reaches the cooling zone by condensing
coils or a water jacket, thus maintaining a fixed vapour level.  Figure IV-1
is a schematic of a traditional open top vapour degreaser.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
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                          Figure W-l

 BASIC VAPOUR DEGREASER - BATCH CLEANING
                              SPRAY
                               TUBE
                    VAPOUR THERMOSTAT
                                                    LIP VENT
 CLEAN OUT
   DOOR
                                                     WATER
                                                    SEPARATOR
                                                     WATER OUTLET


                                                   SOLVENT RETURN
          BOILING SUMP

HEATING ELEMENTS
                  SUMP THERMOSTAT
Source: PPG Industries

              * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

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      Parts are cleaned by lowering them into the vapour zone.  The
temperature differential between the hot vapour and the cool part causes the
vapour to condense on the part and dissolve the contaminants.  The condensed
solvent and contaminants then drip into the boiling solvent.  Parts dry
quickly upon withdrawal from the vapour zone because they are heated by the
•solvent vapours and parts remain immersed in the.vapour until thermal
equilibrium is achieved.

      Vapour degreasing is more effective than cold cleaning, where the
solvent bath becomes increasingly contaminated.  In vapour degreasing, the
parts are washed with pure solvent because contaminants removed from the part
usually boil at higher temperatures than the solvent and therefore remain in
the boiling solvent.  Despite the soils contained in the solvent from
previously cleaned parts, the boiling solvent produces essentially pure
solvent vapours provided that the contaminant level in the boiling sump is
kept low.  Heavy contamination will contaminate the vapour by upward
splashing, as a result of the boiling liquid, or by forming an azeotrope with
the solvent.

      Metals can be cleaned using one of several batch degreasing methods.
These methods are:  vapour-only, vapour-spray-vapour, warm liquid-vapour, or
boiling liquid-warm liquid-vapour.  Modifications to the basic vapour
degreaser process are designed to accommodate various cleaning cycles,
requirements, or parts configurations.  These modifications include spraying
or immersing the parts in boiling or cool solvent.  Immersion vapour
degreasing cycles typically include a warm liquid-vapour cycle and a boiling
liquid-warm liquid-vapour cycle.  Immersion vapour degreasing is used to clean
smalL parts packed in baskets, to clean the inside of tubing, or to clean
intricately .patterned parts contaminated with particularly heavy or adherent
soil.          '             .                                 ,    •

      Vapour-Only:  The simplest degreasing system is the straight vapour
method.  With this method, solvent vapour condenses directly on the part,
dissolves the organic contaminant, and removes it and' any particulate residue
from the surface of the part by dripping back into the boiling solvent.  When
the part reaches the vapour temperature, vapour condensation ceases and.
cleaning is complete.  Parts are dry when removed from the tank.  Few
manufacturers currently make vapour-only units because with the simple
addition of a vapour-spray device the effectiveness and applications of the
machine are greatly increased.

      Vapour-Spray-Vapour:  This cleaning method is similar to the vapour-only
cycle with the addition of a pure distillate rinse step.  In this process, the
metal part is lowered into the vapour zone where the condensing solvent cleans
the metal.  After condensation, the part is sprayed with warm solvent.  The
spray pressure forces the solvent liquid into holes: and helps remove insoluble
soils that cannot be removed by vapour alone.2  The warm spray also .lowers
the temperature of the metal part.  After spraying, the cooled metal part
causes further condensation of vapour for the final rinse.  This technique
also can remove solvent-insoluble soils such as buffing compounds if the part
     2. Spray pressures for standard degreasers should range from 6 psi to 8
psi '(UO KP.a to 55 KPa) (ASM 1982).  Excessive pressure disturbs the vapour
zone and causes a high solvent emission rate.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 is  sprayed  immediately upon entering the  vapour  before  the  vapour heat can
 affect  the  compounds  and make  them difficult to  remove.   Vapour-solvent
 spray-vapour  is  the most frequently used  cleaning cycle  (UNEP 1989).

      Warm  Liquid-Vapour Cycle:   During the  warm liquid-vapour cycle,  the  part
 is  held in  the vapour zone  until  condensation stops  and'then lowered  into  the
 warm  liquid.  Alternatively, parts may be directly lowered  into the warm
 liquid.  Mechanical agitation  of  the warm liquid removes  additional soil.   The
 part  is transferred from the warm liquid  to  the  vapour  zone for a final rinse.

      Boiling Liquid-Warm Liquid-Vapour Cycle:   This cycle  cleans small,
 intricate parts  that  are packed closely together in  baskets,  tubing interiors,
 or  parts with heavy or adherent soil.   A  part is first held in the vapour  zone
 and then lowered into the boiling liquid.  In some processes,  the part is
 lowered directly into the boiling liquid.  Once  immersed  in the boiling
 solvent, the  violent  boiling action scrubs off heavy soil deposits, metal
 chips,  and  insolubles.   Prior  to  the final vapour phase cleaning,  the  metal
 surface temperature of the  part is lowered by transferring  the part to warm
 liquid.  This method  requires  large quantities of solvent and is  impractical
.for large parts  because of  the large volumes of  liquid  solvent required for
 immersion.

      4.2.3.3 Conveyorized Cleaning

      Conveyorized cleaning equipment using  1,1,1-trichloroethane or  CFC-113
 is  generally  configured with a spray, cleaning stage,  immersion in one  to three
 boiling liquid sumps  with ultrasonics to  enhance cleaning,  and in some cases  a
 superheated drying zcme.  Small degreasing machines  using 1,1,1-
 trichloroethane  or CFC-113  may also use ultrasonics  to  enhance cleaning of
 small parts and  equipment.   Vibratory Conveyorized machines which move small
 parts in a  screw pattern upward through chlorinated  solvent liquid arid vapour
 are 'still used.

      4.2.,3.4 Manual Cleaning

      Metal surfaces  can be hand-wiped with  a cloth,  brush,  or sponge  that is
 moistened with solvent.   Solvent  containers  can  be distributed and moved
 throughout  the shop as needed  (ICF 1989).  Prior to  final assembly, and again
 before  pairiiting,  aircraft and  automobile  surfaces, for  example,  are hand-wiped
 clean using,solvents.   Although widely used  in assembly plants; manual
 cleaning is an inefficient  method of cleaning parts  and does not  lend  itself
 to  continuous manufacturing operations.   It  is most  appropriate for infrequent
 maintenance cleaning.

      .4.2.3.5 Spraying and Flushing Techniques

      The effectiveness of  spraying and flushing cleaning techniques  depends
 on  the  solubility of  the soil  in  the selected cleaning media.   Spraying and
 flushing equipment usually  consists of a  solvent tank,  feeder hose,, spray  gun,
 overspray containment,  and  baskets to hold the parts during cleaning.   Solvent
 is  usually  supplied by a mechanical pump  or  a compressed  air mechanism.  These
 methods are most efficient  when cleaning  outer, metal surfaces.  Flushing can'
 clean external and internal part  surfaces such as metal castings,  tubing,  heat
 exchangers, and  assemblies  with large cavities.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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4.3   ALTERNATIVES FOR REDUCING OR REPLACING CFC-113 AND 1.1.1-TRICHLOROETHANE
      USE IN METAL CLEANING APPLICATIONS

      The control approaches available for metal cleaning operations include
solvent conservation and recovery practices and the use of alternative
cleaning such as solvent.blends, aqueous cleaners, emulsion cleaners,
mechanical cleaning, thermal vacuum de-oiling, and no-clean alternatives.
Alternatives to CFC-113 and 1,1,1-trichloroethane must be selected and
optimized for each application given the varying substrate materials, soils,
cleanliness requirements, process specifications, end uses encountered in
metal cleaning, and the local environmental, safety, and health requirements.
Table IV-1 lists the alternatives that can be used for each process.

      4.3.1  Conservation and Recovery Practices

      Methods of conserving and recovering CFC-113 and 1,1,1-trichloroethane
solvents range from simple procedures for manually removing large contaminants
prior to degreasing to adding various filtration apparatuses.

      In a poorly maintained plant, only about 20 percent of the purchased
solvent quantity is generally recovered.  Depending on what measures have
already been adopted at a plant, applications of the guidelines summarized  in
Appendix C can enable total emissions to be reduced by 90 percent.  Solvent
losses can be reduced from 2-5 kg/h-m2 of bath area'with conventional practice
to 0.2 - 0.5 kg/h-m2 of bath area.   For certain alcohol and partially aqueous
systems, the overall base rate of annual loss is around 0.03 - 0.05 kg/h-m2 of
bath area.

      The recommendations summarized in Appendix C are concerned with the best
available technology for the following:

      •     cold cleaning
      •     vapour cleaning (including equipment with spray/ultrasound)
      •     continuous "in-line" cleaning..

      4.3.2   Alternative Chlorinated Solvents

       The chlorinated solvents that do not destroy the ozone layer,
trichloroethylene, perchloroethylene, and methylene chloride (dichloro-
methane)--also are effective cleaners.  Because of their widespread use, they
have been extensively scrutinized for their safety, health, and environmental
impacts.  Many countries have established exposure levels that are considered
safe for workers.  In addition, many countries have placed additional controls
on emissions to the atmosphere from processes using these solvents.  Local
regulations, Material-Safety Data Shee.ts, and industrial recommendations such
as those of the American Conference of Governmental Industrial Hygienists
should be used as guidance in establishing safe handling and usage prbcedures
for these solvents.
      There are specific metal cleaning operations in which trichloroethylene,
perchloroethylene, and methylene chloride are perceived to be the only
alternatives to CFC-113 and 1,1,1-trichloroethane.  Lack of alternatives can
result from concerns abput corrosion of the subs.trate metal (e.g. mild steel),
time restrictions between processes (e.g. degreasing as part of a. metal heat
treating operation), and requirements for removing e-xtremely tenacious soils
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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          Table IV-1.
VIABLE ALTERNATIVES TO  EXISTING METAL CLEANING
         PROCESS SOLVENTS
        Substitute
    Cold        Hot    .    Vapour
 Immersion0   Immersion0   Degreasing
  High
Pressure
  Spray     Manual
Alkaline Cleaners            X

Emulsion Cleaners            X

Low Vapour Pressure
Solvent Blends3    .     • •    X

Hydrocarbon/Surfactant
                 X

                 X


                 X
a  Nonhalogenated mixtures.

b  With appropriate flammability protection.

c  Includes agitation  such  as  ultrasonics,  mechanical, etc.

Source:  Evanoff  1989.  .                                  ;
    X

    Xb


    Xb
X
Blends
HCFCs
Naph tha/Hy dr o c arb ons
Naphtha -Terpene Blends
Other Chlorinated Solvents
Steam

Media Blasting
X
X • X ' X
X
X
X ' X. X

X



xb •
xb
X
X

X
X
X

*
X



                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       4-9

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(e.g. asphaltics and waxes) or cleaning intricate parts configurations  (e.g.
tubes, metal honeycomb).  In these special cases, use of trichloroethylene,
perchloroethylene, or methylene chloride with the incorporation of  the
conservation and recovery practices discussed in this report will not only
reduce the use of CFC-113 and 1,1,1-trichloroethane, but will also  keep use
within local regulatory units.

      Other compounds that recently have emerged as immersion and wipe
cleaning solvents include hydrocarbon/surfactant blends, dibasic acid esters,
n-methyl pyrrolidine, volatile methyl siloxanes, and chlorinated aromatics.
These products are each tested for performance, toxicity, exposure  limits,
flammability, carcinogenicity, odour, recyclability, and cost.  The.U.S.
Department of Energy (DOE) and the U.S. Air Force are evaluating these
products for toxicity exposure limits, flammability, carcinogenicity, and
costs.  These products are also being.tested for cleaning performance,
treatability, recyclability, corrosivity, and VOC emissions. These
alternatives may become increasingly available  for  commercial use over  the
next five years.

      4.3.3  Alternative Solvent Blends

      4.3.3.1  Vapour Degreasing

       The hydrofluorocarbon (HCFC) blends have ozone-depletion factors
associated with them, although these factors are lower than those of CFC-113.
HCFC-123 and HCFC-141b have significantly lower boiling points (27-32°C) than
CFC-113 (48°C) or 1,1,1-trichloroethane (73°C).  This raises the possibility
of increased vapour emissions from operating processes, increased fugitive
emissions during material transfer, and increased handling and storage
requirements.  The boiling point of HCFC-225 is 51-56°C, which is equivalent .
to that of CFC-113.  Blends of HCFC-225 therefore could be an alternative to
CFC-113.  HCFCs should be used with a recovery  system in order to prevent •
solvent emissions, which will minimize worker exposure and-protect  the  global
environment  (Yamabe 1991).                               '

      4.3.3.2  Manual Cleaning

      For manual cleaning, a number of commercial solvent blends are
available.  These products are mixtures of aliphatic and oxygenated
hydrocarbon solvents (e.g., ketones, ethers, esters, and alcohols).  All
degreasing solvents and the organic constituents of blends are volatile and
many are flammable.  Such solvents or blends may require control measures in
.accordance with local, regional, or federal regulations or with corporate
policies governing their use.  These control measures address concerns  over
environmental, health, and safety issues.               i

      The newer blends being developed are optimised for maximum soil removal,
minimum flammability and toxicity, and low composite vapour pressure/
evaporation rate.  These blends are viable substitutes for 1,1,1-
trichloroethane and CFC-113 in situations where volatile organic compounds can
be controlled or are not regulated.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      4.3.3.3  Cold Immersion Cleaning

      Solvent blends of aliphatic naphtha and certain terpenes and dibasic
esters are commonly used in immersion cleaning of heavy soils and greases in
industrial maintenance operations.  These blends are viable substitutes for
1,1,1-trichloroethane and CFC-113 where possible hydrocarbon residue from the
high molecular weight fraction of the naphtha does not ,pose problems and
volatile organic compounds can either be controlled or are not regulated.  The
newer blends being marketed have equal cleaning capacity to those that contain
halogenated solvents.  These include high flash aliphatic naphthas, blends of
aliphatic naphthas with terpenes or esters, and hydrocarbon/surfactant blends.

      HCFC-225 is another alternative that has recently become commercially
available for use ,in cold cleaning applications.  Figure IV-2 shows the
degreasing performance of HCFC-225 compared with that of CFC-113 in cold
immersion cleaning.  It appears that the degreasing ability of HCFC-225 is
comparable to that of CFC-113, thereby making it a suitable alternative.

      4.3.4  Aqueous Cleaners

      4.3.4.1  Cleaner Formulations

      Aqueous cleaners are a viable, broad substitute for CFC-113 and 1,1,1-
trichloroethane used in degreasing metals.  It is estimated that at least 60
percent of the ozone-depleting solvent degreasing operations for metals could
be replaced with aqueous cleaners (Kurita, 1991a).  Aqueous cleaners are.
comprised of three major types of components:

      •     builders -- alkaline salts such as sodium tripolyphosphate, sodium
            silicate, or sodium hydroxide which make up the largest fraction
            of the cleaner.

      •     surfactants •-- organic compounds such -as alkyl benzene sulfonates
            or polyethoxylated high molecular weight 'alcohols that serve as
            wetting and emulsifying agents and thus are the principal source
            of the detersive properties of the cleaner...

      •     additives - - organic or inorganic compounds such as the
            ethanolamines or sodium citrate that serve as complexing agents
            for softening water or binding with undesirable metal ions in
            solution.  Corrosion inhibitors are also added to minimise the
            effect of the aqueous cleaners on the metal surface.3  Numerous
            handbooks artd technical references are available and provide a
            comprehensive explanation of aqueous cleaner chemistry and
            performance (Linford 1950, Spring 1974, U.S. EPA 1991a).

      Alkaline cleaners have been applied successfully in detailed bench and
pilot scale testing for metal cleaning applications and,.since 1992, in full-
scale manufacturing of aerospace components at Boeing, Lockheed, McDonnell
     3  Silicate salts are typical corrosion inhibitors.  Other additives
include anti-oxidants, such as borates,  stabilizers, and  small amounts  of
water-miscible solvents, such as  some  glycol ethers.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     4-11

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                     Figure IV-2
   DEGREASING PERFORMANCE OF HCFC-225
           (Drawing Oil (Houghton Oil))
   100
   80
•o
0
   60
O  40
   20
          I   I    I    I   I    III
• HCFC-225

O CFC-113
                            III!
             10      20      30     40
                Cleaning Time (sec)
                  50
         * 199A UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                      4-12

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.Douglas, Northrop,  and other  aerospace  and automobile  manufacturing
facilities(Golden,  et.al.  1988,  Evanoff 1988,  1994,  Suciu 1989).   These
studies and process changes have demonstrated  that  alkaline  cleaners  are
effective  in  situations where a  broad spectrum of soils  are  present and a
variety of substrate materials are  being cleaned.   Hundreds  of alkaline
cleaning formulations are  commercially  available and more are  currently under
development.   These products  should be  screened for specific applications to
ensure that they  meet the  soil removal  requirements, are compatible with
substrate materials,  and do not  leave residues harmful to the  surface or
downstream surface  coating processes.

      As an alternative to 1,1,1-trichloroethane and CFC-113 use,  the U.S. Air
Force is specifying the use of Mil-C-87937 Cleaning Compound.   A  corrosion
preventative  compound is required if the article is not  coated immediately
after cleaning.   The Air Force is using aqueous cleaning solutions for
degreasing of landing gear.

      Acidic  cleaners^  are used  to  remove  .rust  and  scale  which  cannot  be
removed by organic  solvents.   They  are  also used to clean aluminum, a metal
susceptible to etching when cleaned with strong alkaline cleaners.  In
general, acidic cleaners cannot  be  used as substitutes in organic cleaning
applications            .      ' •

      4.3.4.2  Aqueous  Cleaning  Processes

      The principal stages in aqueous cleaning are  washing,  rinsing,  and
drying (See Figure  IV-3).  Soil  removal is influenced  by thermal
(temperature),  chemical (concentration),  and mechanical  (agitation) energies.
These can be  optimised for specific cases.   Mechanical energy  in  washing  and
rinsing can be provided through  ultrasonics, immersion with  agitation of  the
cleaning solution, or of the parts,  and  spraying.  Aqueous cleaning equipment
can be characterized as either in-line  equipment, used for high throughput
cleaning requirements,  or  batch  equipment  used for  low throughput such as
maintenance applications or smaller production processes,  or in areas where
additional, metalworking is required prior  to finishing.   In-line  and  batch
equipment can be  further subdivided into immersion,  spray, and ultrasonic
equipment.  Equipment design  features and  options vary.   Options  include
solution heater.s, dryers,  parts  handling automation equipment,  in-process
solution filtration,  and solution recycle  and  treatment  equipment.  .Immersion
cleaning, ultrasonic cleaning, and  spray cleaning processes  are described
below.

      4.3.4.2.1   Immersion Cleaning

      Aqueous immersion cleaning combines  chemical,  thermal, and  mechanical
energies.  Immersion cleaning consists  of  four major steps:  cleaning,  rinsing,
drying, and wastewater  treatment (recycling or disposal).

      In the  cleaning process, the  parts are immersed  in a solution and some
form of agitation is added to provide the  mechanical energy  needed to
     * Acidic cleaners contain mineral acids  (nitric, sulfuric, phosphoric,
and hydrofluoric), chromic  acid,  or  organic  acids  (acetic  and oxalic)  plus
detergents, chelating  agents,  and small  amounts  of water-miscible  solvents.

                    * 1994 UNEP SOLVENTS, COATINGS, 'AND ADHESIVES REPORT  *

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                               Figure IV-3

 CONFIGURATION OF AQUEOUS CLEANING PROCESS
       Parts from
      Manufacturing
        Process
        Solution
     Racirculation:
 Filtering, Skimming
                   Wash
                   Stage:
                Heated Detergent
                Solution: Spray,
                Immersion
                Ultrasonics, etc.
   Rinse
   Stage:
   Water:
Spray. Immersion
  Dryer:

Room Temp Air
or Healed Air
                     Periodic Removal
Cleaned
Parts Ready
for Continued
Production
                  Waste Treatment
Source: EPA1989a
                                        flMMII

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displace, dissolve, saponify, and emulsify soils.  The cleaned parts  are
rinsed with deionised or relatively pure water.  Additives may be added to
enhance wash solution displacement and decrease the amount of water drag-out
prior to drying.        .       • •             .     •
                                                       /
      Rinsing removes any.remaining contaminants and cleaning solution drag-
out and may serve as a final finishing step.  Rinsing is an essential step  in
most aqueous cleaning applications.  Care should be taken to prevent  cleaning
fluids from being trapped in holes and capillary spaces.  Low surface tension
cleaners sometimes penetrate spaces and are not easily displaced by the higher
surface tension rinse water.  Drying helps prevent surface oxide formation,
eliminates potential corrosion caused by solution penetration between close
tolerance surfaces, and dries parts for further manufacturing activities.5
Drying can be a major challenge in aqueous cleaning.  In the case of  simple
geometric or  flat surfaces, the challenges may be minimal, but for complex
parts, rinsing and drying may require considerable engineering analysis and
experimentation.  A combination of mechanical methods and multiple operations
may be required to displace the cleaning solution from the surfaces of. a
geometrically complex part.  From the perspective of energy or process time,^
evaporative removal of bulk water is usually not practical.  Compact  turbine
blowers with filtered output can mechanically remove 90 percent or more of the
water.  Care must be taken to assure desired air quality by appropriate
filtration of oil, particulates, and moisture.  Noise reduction, humidity, and
air conditioning control are other considerations.  Conventional convective
ovens can be used for drying.  'For certain lower temperature drying
requirements, vacuum dryers can be custom designed and fabricated.

      The simplest aqueous immersion cleaning machine configuration consists
of a single wash tank.  The demands of most cleaning jobs, however, will
likely require more complex equipment configurations.  If a part must be
cleaned to a high degree of cleanliness or if the quality of downstream
process solutions is a great concern, several wash 'and. rinse stages would be
required.

      4.3.4.2.2  Ultrasonic Cleaning

      Ultrasonic cleaning effectively cleans intricate parts and contaminants
such as carbon and buffing compounds that are difficult, to remove (Randall
1988a, Oakite 1988).  Ultrasonic machines are appropriate for cleaning small,
parts.       '        '                            •          .

      Ultrasonic cleaning equipment creates submicron-sized vapour bubbles at
the metal surface by vibrating the cleaning solution at extremely high
frequencies.  As the bubbles form and collapse, xthey create a scrubbing action
that cleans the entire surface of the parts, including blind holes -and very
small cracks and recesses (Unique Industries 1988).  This cavitation  process
creates extremely high temperatures and turbulence on a microscopic scale.
Transducers vibrate the tank (and hence the cleaning solution) at frequencies
from 25kHz to 40kHz (Branson 1988).6.
.  •   5 Some manufacturing processes require dried parts; others such as many
metal finishing process lines  (anodizing or electroplating) do not.

     6 1 kHz equals 1,000 vibrations per second.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

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       Gross contamination of parts may reduce  the  effectiveness  of  ultrasonic
cleaning.  These contaminants are most effectively  removed  in  a heated
immersion tank with agitated cleaning solution  or in  a  spray washer  (Randall
1988b).  Based on research performed by the U.S. Air  Force, it has been
determined that ultrasonic cleaning enhances  the corrosivity of the  solvents.
Process design requires caution  to ensure  that  the  ultrasonics do not  cause
any metal surface corrosion or damage to the  parts.   It also uses relatively
large  amounts of electricity compared to agitation  immersion cleaners  of
similar size (Racquet 1988).  Aqueous ultrasonic cleaning equipment  can be
configured with other cleaning stages featuring parts and/or fluid agitation,
or it  may be used as one  step in a spray machine.   The  ultrasonic/spray
combination is more common for solvent-based  equipment  than for aqueous
equipment.

       As an alternative to 1,1,1-trichloroethane vapour degreasing,  the U.S.
Air Force is recommending the use of dip tank and ultrasonic cleaning
procedures utilizing ah aqueous  cleaner  (Kelly  AFB).

       4.3.4.2.3  Spray Cleaning

       Spray equipment cleans parts with a  solution  sprayed  at  pressures from
as low as 14 kPa to 2758  kPa or  more.  Depending upon the resilience of the
surface to be cleaned, high velocity spray can  be used  to physically displace
soils.  In general, the higher the spray pressure,  the  more mechanical energy
is provided in removing soil from metal surfaces.   Spray cleaners incorporate
low-foaming detergents 'which are not as chemically  energetic as those  used  in
immersion cleaners but are enhanced by the mechanical agitation.  Spray
cleaning is. effective on  flat surfaces and those made up of simple geometric
parts. Certain configurations such as the  interior  of an automobile  tailpipe,
blind  holes in machined parts, and other complex geometries have  soiled areas
that are inaccessible to  the sprayed cleaning solution;  in  these  instances,
immersion cleaners are more> appropriate.

       One difference in  spray cleaning equipment is  the way in which  each
generates mechanical energy to clean parts.   While  the  mechanical action of
spray  cleaning equipment  is spray action,  the mechanical action of an
immersion machine may be  created by ultrasonic  waves, vertical agitation of
parts, or bath turbulence.  A custom spray machine  can  combine spray action
with the mechanical action used  in immersion  equipment.  Where possible,  a
high pressure spray is an effective final  rinse step.  Optimization  of nozzle
design such as spray pattern, drop size and formation,  pressure/velocity, and
volume are very important and have a major impact on  rinse  effectiveness.
Spray  rinsing uses less water and can provide cleaner surfaces than  an
immersion bath, since the final  water which contacts  the part  can be quite
pure.

       The major differences among spray machines, however,  relate to the
manner in which the parts are handled.  Spray washers are of three general
types: batch, conveyor, and rotary.

       Batch Spray Equipment:  Batch spray  cleaning  equipment consists  of a
.tank to hold the cleaning solution and a spray  chamber  with a  door.  Although
batch  spray.machines have a single spray chamber, it  is possible  to  rinse
parts  in the same chamber by using a separate set of  "plumbing" equipment to
spray  water on the parts.  The rinse water is then  channelled  away  from the


                    * 1994 UNEP SOLVENTS, COATINGS, AND'ADHESIVES  REPORT *

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 tank holding the cleaning solution (Kelly 1988).  These chambers can be manual
 or automated.

       Batch spray machines can be used fo-r maintenance or manufacturing
 applications, but generally do not clean as thoroughly as multiple stage
 machines.  Because maintenance applications tend to have lower throughput
 requirements than manufacturing applications, batch spray machines often are
 used for maintenance cleaning.  For precleaning of heavy soils, large cabinet
 wash and rinse chambers with spray nozzles located around the perimeter are
 available and have been designed to accommodate objects as large as electric
 motors and engines of trains.  For removal of heavy greases and tars, high
 pressure steam is an excellent medium for precleaning and, for some equipment
 maintenance activities, will provide acceptable cleanliness.  This approach
 has the advantage that the soil and condensate will rapidly separate into
 water and oil phases, and in most countries neither phase is considered a .
 hazardous waste.  Currently Tinker AFB personnel have incorporated an aqueous,
 biodegradable solvent into their batch spray system to replace 1,1,1-
 trichloroethane solvents.  Results to date have been satisfactory.

       Conveyorised Spray Equipment:  Conveyorised spray cleaning equipment
'consists of a tank to hold the cleaning solution,  a spray chamber, and a
 conveyor to feed parts through the machine.  A more complex Conveyorised
 system includes multiple wash and/or rinse stages along the conveyor, each
 -stage with its own tank.  The rinse water may be recirculated, especially if
 it contains a treatment chemical such as a rust inhibitor.  The rinse water
 may be discharged if throughput is high or if parts drag significant
 quantities of cleaning solution out of the wash stages.

       Conveyorised equipment is usually used in manufacturing applications
 with, high throughput requirements where parts have flat,  even, controlled
 surfaces.  The advantages1of Conveyorised equipment are high throughput and
 automated parts handling.  If parts are processed before cleaning so that they
 may be handled automatically from a process conveyor,  it may be unnecessary to
 manually handle the par.ts during cleaning.  Conveyorised spray washers .can
 clean all sizes of parts from a variety of industries.,' The amount of wash and
 rinse water required per unit surface area of the part can be as low as 10
 percent of that used in batch cleaning.  This approach reduces the amount of
 wastewater generated as compared to immersion'cleaning and rinsing.   For small
 parts with uneven and curved.surfaces that may not be readily cleaned with
 immersion and agitation, dishwasher-type units with rotating parts holders and
 multi-directional spray.nozzles are available.

       Rotary Spray Equipment:'  Rotary spray equipment is very similar to
 Conveyorised spray equipment except-for the manner in which parts are handled..
 A rotary machine employs a steel drum with a partition that spirals, along the
 inner surface of the drum such that when the drum is rotating, parts will be
 transported along the length of the drum.  The drum is. perforated so the spray
 can impinge on the parts to be cleaned.

       Rotary spray washers are designed to clean small parts such as screw
 machine parts (e.g.,  nuts and bolts)  and small metal stampings.  Rotary
 equipment can clean large volumes of parts, but the parts must be able to
 withstand the tumbling action of the rotating drum.  Parts with delicate outer
 diameter threads and polished parts that should not be scratched should be
 cleaned in a different type of machine using a.basket with a locking lid that


                   . " 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      A-1 7

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can hold the parts in place during cleaning (Taylor 1988).  High throughput
can be achieved with these machines, making them good candidates for high
volume manufacturing operations.  One tradeoff, however, is that the rotary
machines.require more energy input than other types,of spray machines.

      4.3.5  Hydrocarbon/surfactant ("Semi-aqueous" and "Emulsion") Cleaners

      Hydrocarbon/surfactant blends are emulsion cleaners that have been
developed, tested extensively and are beginning to be used as substitutes for
CFC-113 and 1,1,1-trichloroethane in metal cleaning applications which
incorporate high viscosity and high molecular weight soils, semi-solid soils,
and corrosion sensitive substrates.  Hydrocarbon/surfactants are included in
many different cleaners and are formulated for different purposes.  Examples
of these families of chemicals are the terpene hydrocarbons and glycol ethers.

      Hydrocarbon/surfactants are used in cleaning processes in two ways.
They are either emulsified/diluted in water and applied in a manner similar to
standard aqueous cleaners or they are applied in a concentrated form and then
rinsed with water.  Because both methods use water in the cleaning process,
the hydrocarbon/surfactant-based process is commonly referred to as a semi-
aqueous process.

      The benefits of semi-aqueous cleaning processes include the following:

      •     Good cleaning ability (especially for heavy grease, tar, waxes,
            and hard to remove soils)
      •     Compatibility with most metals and plastics
      •     Suppressed vapour pressure (especially if used in emulsified form)
      •     Nonalkalinity of process reduces corrosion potential and reduces
            the metal content of wastestreams
      •     Reduced evaporative loss
      •     Potential decrease in solvent consumption which may lower overall
            cost
      •     Ability of some formulas to separate easily from water.        "

The drawbacks include:

      •     Recycling or disposal cost of wastewater could make the process
            less economically viable
      •     Flammability concerns if concentrated cleaner is used in spray
            cleaners
      •     Special equipment designs may be needed to account for
            flammability
            Objectionable odours with some cleaners, such as'terpenes
            VOCs are major components of some cleaners
            Drying equipment will be required in most applications .
            Gelling of some cleaners in low water-content emulsions
            Difficulty in reducing surfactants used in cleaners
            Toxicity considerations not yet defined for all cleaners
            Auto-oxidization of some cleaners.  For. example, .d-limonene  (a
            type of terpene) can auto-oxidize.  The terpene suffers auto-
            oxidation naturally from contact with air.  This can in some
            instances be reduced using antioxidant additive .
            Semi-aqueous cleaning systems may require more floor space in some
            instances                       '


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     4-18

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      •     Energy consumption may be higher than that of solvent cleaning
            systems in applications that require heated rinse and drying
            stages
      •     In some applications, high purity water, which is expensive,, may
            be needed.

      The steps in a typical semi-aqueous cleaning process are analogous to
aqueous cleaning (see Figure IV-4).   Equipment for use with semi-aqueous
processes are modifications of aqueous cleaning equipment design.  In cases
where extreme cleanliness is required, hydrocarbon/surfactant cleaning can be
followed by a fully aqueous wash step with an alkaline detergent and a
deionized water rinse.  Application methods that avoid misting such as spin-
under immersion or ultrasonics should be used.

      Dilute hydrocarbon emulsion cleaners formulated with water may be
heated.  Less mechanical energy is needed when using a hydrocarbon/surfactant
solution than when using an aqueous solution, because of the high solvency of
hydrocarbon/surfactant cleaners.  Rinsing with clean water removes the
residues left by the wash step.

      Equipment for use specifically with concentrated hydrocarbon/surfactants
is available.  As with aqueous cleaning, this can be classified as immersion
or spray equipment'and as either batch or in-line equipment.  Because of the .
solvency of hydrocarbon/surfactants, less mechanical energy is required than
in aqueous cleaning to achieve adequate cleanliness..  Emulsion cleaners also
effectively clean metal parts using ultrasonics.

      4.3.6  Mechanical Cleaning

      Various mechanical cleaning methods have been used for metal surface
preparation and proposed as possible alternatives for CFC-113 and 1,1,1-
trichloroethane.  Brushing, wiping with rags.or sponges, use of sorbent
materials, media blasting, and pressurized gases are being investigated to
various degrees.  These methods, however, are generally best suited for lower
grade cleaning requirements or as a precleaning operation.in the removal of
solid and semi-solid soils.

      Pressurized gas may be used in some cases for particulate contamination
as an alternative to cleaning with 1,1,1-trichloroethane and CFC-113.  Gases
which may be used include air, rare earth gases, carbon dioxide, and nitrogen.
These gases are readily available in bulk and smaller quantities and in
numerous grades of purity.  The advantages of cleaning with pressurized .gases
versus 1,1,1-trichloroethane  include the following: low viscosity, low
toxicity,  high diffusivity, nonflammability, and low capital cost.
Disadvantages of using pressurized gas  include: low density, high pressure,
cleaning of critical components, and often ineffectiveness in cleaning
microscopic particles.

      Specific technologies under development include wheat starch blasting,
sodium bicarbonate blasting, and carbon dioxide (solid) blasting.  These
methods and others being developed will be evaluated by DOE in collaboration
with the U.S. Air Force.  Wheat starch can be dissolved in rinse water for
disposal and is not considered a hazardous waste after the oils and greases
are skimmed off.  The carbon dioxide evaporates after cleaning leaving the oil
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     6-1 Q

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                  Figure IV-4

     SEMI-AQUEOUS PROCESS FOR
IMMISCIBLE HYDROCARBON SOLVENT
Hydrocarbon/
 Surfactant
 Waah Stag*
Emulsion
 Rlnaa
Rlnaa
  Dryar
Foread Hot Air
Hydrocarbon/
 Surfactant

  Rauaa
 DIspOM or
  Racycl*
                                             Ctaanad
                                             Parta
                              0CloMdLoepWatar
                                Site Water
                                TraatmMrt or

                              Ooirad to Drain
                   Dacantar
     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

                    4-20

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and grease contaminates behind, thereby reducing the volume of waste
generated.  Carbon dioxide blasting  is currently being used for paint
stripping but may be too forceful for less problematic cleaning needs  (Kelly
AFB) .

      4.3.7 Thermal Vacuum De-oiling

      Thermal vacuum de-oiling  is a  system that uses a heated vacuum chamber
to remove oil from parts by vapourising the oil.  The vapours are then pumped
through a cold trap where they  are condensed and drained from .the system for
recycle or disposal.  Typical cleaning applications for vacuum de-oiling are
parts of either simple or complex design that are soiled with low- to mid-
viscosity oils.  This technology can be used to.successfully clean parts
following cutting, machining, quenching, and stamping operations.  Vacuum de-
oiling is also used to clean parts in preparation for brazing, coating,
plating, and heat treating operations.

      Advantages of vacuum de-oiling include the following:  elimination of
cleaning solvents., provision of ultraclean parts, simple operation of      •
equipment, reclamation of oils, floor space requirements similar to that of
vapour degreaser equipment, and generally no need for environmental permits.
The primary disadvantage of vacuum cleaning is that the system is very soil
specific.  Vacuum cleaning is only capable of removing oils that can be
volatilized within certain temperature, time, and pressure ranges.  The
equipment settings for these variables depend on the characteristics of the
oil being removed as well as the mass and surface area of the parts being
cleaned.  For these reasons vacuum cleaning systems work best in manufacturing
applications that have consistent part size and soil loading.

      A number of volatile machining oils and forming lubricants are currently
available to produce metallic parts  without vacuum system or cleaning
processes.  For example, a heat exchanger of a domestic air-conditioning unit
has been made by aluminum fins  and copper tubes with many kinds of machining
oils and forming lubricants.  Traditionally, large amounts of 1,1,1-
trichloroethane have been used  for removing these oils (Matsui 1991).

      4.3.8 No-Clean Alternatives

      A number of water-soluble and  emulsifiable machining and metal forming
lubricants are available.  These products are easier to clean using aqueous or
semi-aqueous cleaners and are less of a concern for worker exposure.  Hot
water immersion, spray, or hot  water immersion with ultrasonic may be   . v
sufficient for removing lubricants that contain emulsifiers.  Lubricant spray
applicators which discharge a fine well-controlled mist can decrease lubricant
usage without affecting product quality.  Other alternative lubricants under
development include "dry" lubricants and thin polymer sheeting which can be
peeled from the surface after the metal forming operation, or in the case of
tube forming, "empty tube bending" which accomplishes the forming operation
without the use of a lubricant.  These products and methods are not standard
industrial practices.  They do, however, offer the potential for eliminating
the need for degreasing.

      Material flow through production should also be reassessed to minimise
the number of times that a part is degreased and to consolidate the cleaning
operations into a centralised unit or location.  In many plants, parts are


                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                                     /, 01

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 degreased two  and possibly three times before finishing and assembly.
 Consolidation  of cleaning operations will decrease the amount of solution
 treated and waste generated (Evanoff and Weltman 1988).

       Segregation and precleaning of heavily soiled parts can extend bath
 life.   Heavily soiled parts can also be routed separately through a single
 precleaning system;  this  has the effect of decreasing the amount of
 contaminated cleaner being generated in the main production area cleaning
 systems,  because the amount of soil entering these systems is minimised
 (Evanoff and Weltman 1988).  Sorbent methods (sorbent laden pads or cloths)
 can be used to wipe  clean parts and surfaces after initial fabrication,
 thereby reducing the cleaning requirements.

       4.3.9 CFC-113  and 1.1.1-Trichloroethane Processes "for Which Alternatives
             are Not  Available

       Alternatives are currently available for virtually all metal cleaning
 processes that previously used CFC-113 and 1,1,1-trichloroethane.   Those
 applications for which there is no currently available alternative can be put
 into two groups.  First,  there are those applications for which the Parties to
 'the Montreal Protocol have granted an Essential Use Exemption (EUE).   In
 granting these exemptions, the Parties recognize that there are no feasible
 alternatives to the  use of CFC-113 and 1,1,1-trichloroethane in the short
 term.   The second group is comprised of some applications for which
 stockpiling or recycling of CFC-113 and 1,1,1-trichloroethane is to be used to
 satisfy short  term demand for.these solvents.
 4.4  COST OF ALTERNATIVES  •

       Due to the wide variety of alternatives available to replace CFC-113 and
 1,1,1-trichloroethane in metal cleaning applications, a full discussion of the
 costs of these alternatives is not practical.  However, there are several
 universal cost components that should be considered when evaluating
 alternative cleaners or cleaning technologies.   These cost components can be
 split into two groups --one-time costs and recurring costs.

       One-time costs are those costs that are -incurred only at the beginning
 of  a project and are not repeated throughout the project life.  The most
 significant of these costs is often the capital investment in new equipment or
 in  the retrofit of existing equipment.  Other one-t*Lme costs may include items
.such as laboratory and production testing,  environmental,  health, and safety
 impact studies,  equipment installation, personnel training, documentation
 revisions,  and environmental permitting.

       Recurring costs are primarily operating costs.  These costs are incurred
 throughout the lifetime of the equipment or cleaning process and are often
 calculated on an annual basis and compared to the costs of the CFC-113 or
 1,1,1-trichloroethane cleaning process.  Recurring costs may include costs for
 raw materials (cleaning detergents,  solvents, water), energy usage, waste
.treatment/disposal,  and equipment maintenance.          '
                    * 1994 UNEP SOLVENTS, COATINGS, AND.ADHESIVES REPORT *
                                      4-22

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 4.5   ENVIRONMENTAL.  HEALTH.  AND SAFETY CONSIDERATIONS
                                             '»
       This  document  is not a risk assessment and therefore it contains only a
 general  description  of some of the environmental health and safety issues
 associated  with each alternative-cleaner or cleaning technology.   The health
 and  environmental effects of some of these technical options are  still being
 investigated.   Certain commercial solvents are generally recognised as toxic
 while others are suspected but not confirmed as toxic.   Other cleaners
 including aqueous and emulsion cleaners contain constituents which may be
 hazardous or which can have adverse environmental effects if discharged.  .
 Nonetheless, the use of toxic chemicals is permitted in certain cases by
 governmental authorities but usually require strict workplace controls and
 effective waste treatment and/or disposal.  However, regulations  may vary
 depending on location.  In some circumstances  it may be prudent to select
 cleaning options that do not depend as heavily on workplace controls and waste
 treatment.                    -                   ,

       The environmental, health, and safety impacts of the alternative
 compounds that could be used in cleaning applications must be evaluated prior
'to their use.   These impacts may include:   acute and chronic health effects,
 ozone-depletion potential, flammability., aquatic toxicity, global warming
 potential,  and volatile organic compound (VOC) classification.   Potential
 users of alternative cleaners should be; aware  of the acceptability of a
 particular  alternative in their country, region, and locality.   Users should
 consult  local, regional, and federal regulations governing the use, emission,
 or disposal of any solvent cleaner.  Committee members do not endorse the
 worker safety or environmental acceptability of any of the1 technical options
 discussed.
 4.6   POTENTIAL GLOBAL REDUCTION OF CFC-113 AND 1.1.1-TRICHLOROETHANE IN METAL
       CLEANING APPLICATIONS       ' .                                         .  •

       The Committee consensus is that mos,t CFC-113 and 1,1,1-trichloroethane
 used in metal cleaning applications can be replaced by these alternatives in
 accordance with the Montreal Protocol by the year 1996.   Some countries,
 however,  are achieving this phaseout according to their own accelerated
 schedule.  Approximately seventy-five percent of the short-term reduction of
 CFC-113 and 1,1,1-trichloroethane usage is expected to be achieved through
 aqueous cleaning substitution.

       For general degreasing of metal surfaces and parts,  aqueous immersion
 cleaners  and solvent emulsions can be substituted for most metal cleaning
 applications.  Many of these substitutions have already taken place in the
 developed countries and are underway in developing countries.  The remaining
 complex cleaning applications can be replaced by sophisticated aqueous
 cleaning systems or alternative solvent systems.  These complex cleaning
 applications will require extensive research-and design efforts.  It is
 important to allow for the appropriate development time to be sure that
• inappropriate choices that might have significant health,  safety, or
 environmental impacts, are not made.                        ,

       More than 60 percent of 1,1,1-trichloroethane was used by small
 manufacturing companies.  The technical and economic impacts are critical to
 the survival of such companies.  They often lack the resources and technical
                                                                I
                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT "
                                      4-23

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capabilities of larger firms, and essentially must rely on  the  success  of the
larger companies to transfer to the smaller firms.  This would  most  likely
mean the smaller companies will be about two years behind the larger firms in
their phaseout.  The critical needs for smaller firms to make the  changeovers
are:  qualification of and transition to new processes, floor space
requirements, capital cost, and in many cases water treatment technology.
4.7   SUITABILITY OF ALTERNATIVES FOR DEVELOPING COUNTRIES AND  SMALL QUANTITY
      USERS

      Developing countries should be able to closely follow  the same scenario
as the smaller companies in the developed countries.  They may  have an
additional lag time in their own smaller industries.  Each developing country
will have somewhat different scenarios depending upon their  unique industry
basis.

      Developing countries which maintain joint ventures with developed
countries, or with a strong multinational company-based manufacturing base
will be able to incorporate new technology fairly rapidly.   Most multinational
companies plan to transfer their technology as expediently as possible to
their operations in developing countries.  However, there will  need to be a
significant time lag in this technology transfer process as  well.  It is
expected that most multinational companies, including jointly owned affiliate
companies should be able to transition their developing country operations
within two years of their home operations.

      Potential alternatives discussed in this chapter, as well as emerging
and developing technologies, will be able to substitute for  CFC-113 and 1,1,1-
trichloroethane use in all applications, but especially for  1,1,1-
trichloroethane in metal cleaning applications.  Since'more  than 60 percent  of
annual consumption of 1,1,1-trichlorpethane has been used by sm&ll and medium
enterprises (SMEs),  both technological and economical impacts are essential.
Promotion of technology disclosure and even subsidization could be necessary
for average SMEs.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     4-24

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                                   CHAPTER 5

                             DRY CLEANING INDUSTRY
5,1    .BACKGROUND

       Dry cleaning  enables  the  cleansing  and  reuse  of fabrics  that  cannot  be
cleaned by alternative methods.   The  inherent environmental  friendliness of
restoring freshness to soiled articles  and garments is matched by extreme
efficiency in  terms of solvent  and  energy use in  the dry  cleaning process
itself.  Organic solvents are used  to clean fabrics because, unlike water,
they do not  distort some natural  and  synthetic fibres.  Water  cleaning  of  many
materials can  affect the stability  of fabric,  lining,  and interlining and  may
cause  stretching or shrinkage.

       In addition to the actual machine cycle,  the  term "dry cleaning"
includes a large number of  operations:  customer service,  precleaning stain
treatment/heavy soil release, post-cleaning stain treatment, tailoring,
pressing, and  ironing'.  In  such a labour-intensive  business, where  up to 40
percent of receipts are required  for  wages alone, dry cleaners have had strong
financial incentive to pay  close  attention to other operating  costs, including
solvent cost/selling price  ratio.   Even before the  ozone-depletion
contribution of solvents became widely  known,  dry cleaners,  for purely
commercial reasons, had been frugal solvent users.   This  scenario has had  two
other  effects: low  solvent  use/high energy efficiency has been an important
factor in the  purchase of dry cleaning  machines,  and manufacturers  have
competed to  produce and market  increasingly efficient and environmentally  safe
products.

       For many years, dry cleaning  machines have  been totally  enclosed;
incorporating,filtration, distillation, and refrigerated  recovery systems
allows solvents to  be continuously  recycled.   The technology developed  by  some
European dry cleaning machine manufacturers may have applications in the
manufacture  of metal cleaning machines  which  require high solvent efficiency.


5.2    CFC-113  AND 1.1.1-TRICHLOROETHANE USE IN THE  DRY, CLEANING INDUSTRY

fc       CFC-113  is used as a  dry cleaning solvent not only  because  of its low.
toxicity, stability,  nonflammability, and relatively low  boiling  point, the
latter a factor which minimizes energy  requirements during the drying and
distillation,  but also because of its low solvency  power  (31 Kauri  Butanol
Value).  The low solvency allows  the  cleaning of  fabrics  with  sensitive dyes
and trimmings  which may fade or run if  cleaned with other solvents.  CFC-113
when used in conjunction with leather oils is ideal for cleaning  suede  and
leather garments.   As CFC-113 is  phased out,  however,  fashion  designers and
clothing manufacturers will have  less flexibility in their selection and use
of fabrics and trimmings and in the future must construct garments  that can be
dry cleaned  in other solvents.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      5-1

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      The use of 1,1,1-trichloroethane has been limited as a dry cleaning
solvent for a number of reasons. While its high solvency power  (Kauri Butanol
124) removes soiling, easily and thereby reduces the need for prespotting and
recleaning, the solvent damages plastic trimmings, pigment prints, and some
bonded fabrics.  In addition, the capital cost of the cleaning  equipment is
approximately 60 percent higher than the cost of CFC-113 cleaning equipment.
1,1,1-Trichloroethane not only has a strong odour, but is also  heavily
stabilized and, without regular attentions can break down to produce acid
which corrodes the machine and possibly ancillary equipment.

      Another major factor limiting the use of 1,1,1-trichloroethane in dry
cleaning relates to care labelling.  The solvents to be used for cleaning  are
indicated by the marks specified in International Standards Organisation (ISO)
3758.  Few garments carry the care label A which indicates the  garment may be
safely cleaned in 1,1,1-trichloroethane.  The majority of garments are marked
P (clean in perchloroethylene, CFC-113, or.white spirit) or F  (clean in CFC-
113 or white spirit).  If adhered to, these labels protect the  dry cleaner
from liability if the garment is damaged by the dry cleaning process. .

      While no more than a few hundred machines in the US and Europe use
1,1,1-trichloroethane as a dry cleaning solvent, a late-1980s study in Japan
by Ethane Research Working Group, a group comprised of solvent  producers,
research and trade associations, machinery manufacturers, and detergent
producers, generated interest in machines using 1,1,1-trichloroethane.  As a
result, some 2,300 machines were in operation by the beginning  of the 1990s.
However, this number still represented only 4.3 percent of the  total machine
population.

      5.2.1 Dry Cleaning Machines

      A modern dry cleaning machine is similar to a combined washing
machine/tumbler dryer.  The articles are washed in an organic solvent to which
a liquid detergent is added during the. main wash stage.  Following rinsing arid
spinning, the articles are tumble dried in the.same machine.  They are only
removed after all of the solvent has been recovered.  This system, known as a
totally enclosed machine or dry-to-dry process, prevents the solvent emissions
that previously occurred when clothes were cleaned in one unit  and transferred
to a separate dryer (transfer machines).

      A dry cleaning machine is required to complete three prime functions:

       •    To thoroughly clean a wixie variety of garments and  other articles

       •    To enable complete drying of items before they are  taken out of
            the machine
                                                                           I
       •    To purify the solvent for reuse.

      To perform its prime functions, three distinct circuits relating to
solvent, air, and distillation operate within the machine.  Figure V-l shows
the various flows in a simplified form and Figure V-2 details a typical layout
of basic components.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      5-2

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                                   Figure V-l

        BASIC DRYCLEANING  MACHINE PRINCIPLES
  Fan
     Drum
                                      Solvent
                                      Pump
                    Distilled
                    Solvent Tank
                                                                        Still
                                                                        Condenser
              Solvent Circulation •
              Filler Circuit
Air Circulation •
Drying Circuit
Distillation Circuit
Shown simplified are the three most important stages in drycleaning machine
operation:
 • Solvent circulation - filter circuit (cage, button trap, pump, filter, and back to cage).
 • Air circulation -  drying circuit (cage, fan, recovery condenser, air heater and back to cage).

 • Distillation circuit (still, still condenser, water separator, distilled solvent tank).
                                                                             IIK077-2
                   * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

                                      5-3

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                     Figure V-2

TYPICAL LAYOUT OF BASIC COMPONENTS
    1 Cage-
    2 Button Trap
    3 Lint Filter
    4 Fan
    5 Recovery Condenser
    6 Air Heater
7  Solvent Filter
8  Still
9  Still Condenser
10 Water Separator
11  Distilled Solvent Tank
12 Working Tank
        * 1994 UNEP SOLVENTS. COATINGS. AND ADHESIVES REPORT
                       5-4

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 5.3   ALTERNATIVES FOR REDUCING OR REPLACING CFC-113 AND 1.1.1-TRICHLOROETHANE
       USE

       5.3.1 Conservation and Recovery Practices

       Solvent losses in dry cleaning machines result from poor recovery
 (drying),  leakage, distillation losses,  and incorrect handling during
 refilling and servicing.  Table V-l lists some of the reasons for losses from
 these machines.   Improved operator practices and better engineering and
 controls could conserve much Of the CFC-113 and 1,1,1-trichloroethane solvent
 currently lost.   Recycling and recovery technology is already at an advanced
 stage in which totally enclosed machines feature refrigerated condensation of
 solvent vapour and activated carbon adsorption of any trace emissions of
 vapour.  Operation and maintenance practices can also ensure that CFC-113
 emissions are low.  Such practices include activating the drying fan prior to
 opening maintenance manholes and daily cleaning of the lint filter.

       When a machine has not been operated for a number of hours,  solvent
 vapours will fill the machine space.  By activating the drying fan prior to
 opening maintenance manholes, the vapours can be regenerated.  Machines can be
 equipped with a special timing device that activates the drying fan one to
 two minutes prior to opening the machine door, thereby reducing solvent
 losses.  In general, inspection manholes for the cage (cleaning chamber),
 button trap, and lint filter should always remain closed during operation and
 should be opened for the shortest possible interval during servicing.  In
 machines equipped with a button trap that is separate from the regeneration
 system, special precautions should be taken when,cleaning the trap -- all
 residue from it should be placed .in the lint filter for drying.

       Efficient operation of the refrigeration unit in dry. cleaning machines
 can reduce CFC-113 losses by up to 25 percent.  The large variations in the
 size of loads processed by machines result in varying quantities of
 uncondensed vapours being left in the distillation units or machines.
 Monitoring devices are available to measure the various loads on the
 refrigeration unit or heat pump and to be.tter control temperatures.   All CFC
 machines can be fitted with a low pressure sensor and regulator for the
 cooling coils.   Such a device monitors the optimal condition for coil
 operation and switches off the machine when excessive vapour builds up in the
 expansion vent or when the level of refrigerant is inadequate.  When a low
 pressure device is being installed, the evaporation and condensation
 temperatures for the refrigeration cell can be adjusted.  The suppliers for
 the respective machines can provide the relevant values for optimum drying
 efficiency.              .                ' .

       Filter replacement significantly reduces solvent losses.  A small
 filter, for example, contains approximately 4 to 5 kg of solvent after .
 drainage.   With proper filter replacement techniques, this solvent can be
 recovered in the cleaning drum of machines. : Some machines, however, are
 equipped with one large filter or many small filters that do not fit the
 machine drum.  Machines with more than four filters can be reconstructed so
 that filtration takes place only through two filters.  Those filters not
 operating should be put aside for drainage and subsequent regeneration.
 Machines with a single filter that is too large for the drum can be equipped
 with sealed drainage vessels that are attached to the machine's 'regeneration
• system or stored and transported to a special regeneration facility.


                    . * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       5-5

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 Table V-l.  GENERAL SOURCES  OF SOLVENT LOSSES FROM DRY CLEANING MACHINES


Leakage at the  still door

Leakage at the  button trap  hatch

Leakage at the  lint  filter

Leakage at the  loading door

Leakage at the  lids  for the heating and refrigeration chambers

Leakage at the  main  drive  shaft seals

Leakage at the  pipe  connections

Spillage  during refilling

Clogged air-cooled condensers

Substandard  maintenance of the lint filter

Inadequate cooling water flow

.Solvent in the  condensed water

Cleaning  of  the button trap,  especially during operations

Excessive build-up of lint between the outer and. inner drums

Negligence during filter replacement or improper machine design

Inadequate final distillation

Overloading

Underloading

Incorrect assembly and installation

Humidity  in  the cooling system                           • •

Incorrect choice of  temperatures

Substandard  maintenance
                  * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                     5-6

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      A number of daily operation and maintenance activities also can be
conducted to reduce solvent losses from CFC-113 and 1,1,1-trichloroethane
machines.  Because lower air velocity increases drying time, the lint filter
should be cleaned or replaced daily.  Prior to system start-up, the cooling
water circulation system should be checked as well as the refrigeration
system, refrigerant, and oil levels.  In-addition, all seals and gaskets
should be checked weekly and adjusted if necessary.  The machine should not be
overloaded and should be checked to ensure that each load is dried prior to
opening the machine.

      Other preventive maintenance practices include cleaning the still only
when it is cold, ensuring that the temperature of the refrigeration cell does
not fall below the freezing point of the solvent, and regularly cleaning the
temperature sensors.  In addition, the pressure equalization device should be
checked to ensure that solvent is not allowed to escape, and the activated
carbon filter should be inspected to determine the amount of solvent
recovered.  Finally, condensed water from the water separator should be
collected in a transparent container.  Before emptying the container, liquid
should be checked'for the presence of any free -solvent.  If solvent is
present, it should be separated prior to emptying the container.  The contact
water should be disposed of in accordance with the appropriate federal,
regional, and local regulations.

      5.3.2 Alternative Solvents

      A number of solvents can be used as alternatives to CFC-113 and 1,1,1-
trichloroethane in dry cleaning operations.  Table V-2 lists several chemical
characteristics of the alternatives discussed below.

      5.3.2.1     Perchloroethylene

      Perchloroethylene, the most widely used dry cleaning solvent, has been
used in this application for over 30. years, during which time the systems for
its safe use have become highly developed.  For dry cleaners who are seeking
to replace their CFC-113 or 1,1,1-trichlproethane machines, perchloroethylene
is a logical and practical choice.  Its higher solvency power than CFC-113
means that it is not suitable to clean a minority of the fabrics, trims, etc.,
that can be cleaned in CFC-113  (Clark, 1991b).  It is an adequate replacement
for 1,1,1-trichloroethane.        '

      Some studies have implicated perchloroethylene as a possible carcinogen
although recent toxicological and epidemiological evidence indicates that this
is either not proven (EPA 1989b) or due to species differences not relevant to
humans (Clark, - 1991a).  In addition, it is important to bear in mind that
modern perchloroethylene machines are extremely efficient and usually result
in low solvent emissions.  Nonetheless, the use of perchloroethylene in dry
cleaning may be regulated in some countries, regions, or localities.  For
example, the U.S. EPA set national emissions standards for perchloroethylene
in September, 1993 that apply to both- new and existing perchloroethylene dry
cleaning facilities.  These standards were set in part because
perchloroethylene is listed in the Clean Air Act as a hazardous air pollutant,
and because a recent study in Staten Island, New York and New Jersey .concluded.
that perchloroethylene is "among the toxic air pollutants found at the highest
concentrations in urban air (U.S. EPA, 1993)."
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      5-7

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  Table V-2.   CHEMICAL CHARACTERISTICS OF SELECTED DRY CLEANING SOLVENTS
Solvents
CFC-113
Perchloroethylene
Petroleum- Based
Solvents
1, 1,1-Tirichloroethane
HCFC-141b
HCFC-123
HCFC-225
Flamm-
ability
NFb
NF
Fc
NF
F
NF
NF
Boiling
Point
(°C)
47.6
121.2
150-210
74.1
32.1
27.6
51-56 .
Heat Required
to Boil
One Litre8
(Real)
64
116
N/A
90
68
62
63-66
Kauri
Butanol
Value
31
90
26-45
124
58
60
30-34
a Heat required  to boil one litre of solvent  from 20°C.

b NF - Nonflammable.

c F - Flammable.

Sources:  TSA  1991,  Rodgers 1989, Kirk-Othmer 1983, Basu  1989.
                  * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     5-8

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      5.3.2.2     Petroleum Solvents  (White Spirit. Stoddard Solvent. Etc.)

      The flammabili'ty of petroleum solvents effectively precludes their use
in shops, although with proper precautions, they can be a substitute for CFC-
113 on many fabrics.  In Australia, for example, a fabric labelling convention
has been introduced that designates white spirit as a substitute for CFC-113
in the dry cleaning of specific fabrics (Standards Association of Australia,
1987).

      Petroleum solvents include white spirit, Stoddard solvent, hydrocarbon
solvents, isoparrafins,  n-parrafin, etc.  Depending on the solvent,
characteristics such as flash point,  solvency  (Kauri Butanol value),
distillation temperature, etc. will vary.  White spirit and stoddard solvent
were developed for dry cleaning applications 40-50 years ago, and have been
used to some extent in the U.S., Europe, Japan, and Australia.  However, their
use has been gradually decreasing over time because of substitutions made to
nonflammable solvents and because of  regulations restricting emissions of
volatile organic compounds.  In addition, despite epidemiological studies
there are unresolved issues concerning the toxicity of some petroleum
solvents.

      Recent improvements in dry cleaning equipment to maximize recovery of
cleaning solvents while minimizing emissions has resulted in increases in the
use of flammable solvents.  In addition, new petroleum solvents are being
marketed that have lower odour and toxicity.

      5.3.2.3     Hydrochlorofluorocarbons (HCFCs)
                                                               i

      A number of HCFCs and HCFC 'blends are currently available commercially
for use in solvent applications.  These include HCFC-123, HCFC-141b, and HCFC-
225.  These HCFCs have good stability, excellent solvency, and nonflammability
and some HCFCs are suitable for cleaning those delicate fabrics that currently
depend on CFC-113.  Due to its status as a suspected, carcinogen, HCFC-123 is
not being marketed for use in solvent applications and is therefore not a
possible alternative to CFC-113 and 1,1,1-trichloroethane.  In addition, HCFC-
141b is not a recommended alternative, especially for 1,1,1-trichloroethane,
because it has an ozone depletion potential (ODP) comparable to that of 1,1,1-
trichloroethane.  HCFC-225, which is  a blend of the ca and cb isomers, has a
similar boiling point to CFC-113 and  is proving suitable for cleaning many
sensitive fabrics.  Because of dry cleaners' concerns for the solvent
cost/selling price ratio, the cost of the blend will determine how readily it
is used.  It should be noted, however, that HCFCs are transitional
alternatives subject to a phaseout under the Montreal Protocol by the year
2030.         .                                              .

      5.3.2.4     Other Alternative Solvents

      Other classes of chemicals such as iso-paraffins, solvents derived from
sugar cane, and hydrocarbon/surfactant blends  arev theoretically possible
alternative dry cleaning solvents.  More research, however, is necessary to
determine their feasibility for dry cleaning.

      Recently; a large chemical manufacturer  introduced a synthetic, high-
purity hydrocarbon solvent.  Some of  the properties' which may make it a good
dry cleaning solvent include good cleaning power, low odour, long service


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      5-9

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life, high flash point, and low toxicity.  A relatively high flash point of
64°C  (147°F) provides a greater margin of safety over most other hydrocarbon
solvents, thereby reducing building fire suppression requirements in some
areas.  This solvent is currently in use at dry cleaning facilities and the
following properties have been observed  (Exxon, 1994):

      •     compatible with closed-loop, dry-to-dry machines traditionally
            used with perchloroethylene  (PERC) and petroleum solvents
      •     compatible with common additives
      •     requires virtually no deodorants since it is virtually odourless
      •     cycle time comparable to that of a Stoddard solvent, and slightly
            longer than PERC
      •     little or no plant/building modifications except for the approval
            from the Fire Marshal
      •     releases dirt to carbon/clay filters improving cleanliness and
            prolonging solvent life                                   -

Potential users of this or any other flammable solvent should determine their
acceptability given local fire regulations.

      5.3.2.5     Centralized Processing Facilities

      The establishment of centralized cleaning facilities could augment the
controls on solvent losses that can be achieved at small, individual dry
cleaning establishments.  At centralized facilities, additional investments in
control devices and standardized operation and maintenance practices can lead
to more efficient solvent use.
5.4   COST OF ALTERNATIVES

      A dry cleaning machine is the most expensive single item of capital
expenditure incurred when establishing a dry cleaning operation.  Dry cleaning
machines are usually designed to last for 12 to 15 years.  Most CFC-113 and
1,1,1-trichloroethane machines can only function using the original solvent.
A significant portion of the cost of eliminating CFC-113 or 1,1,1-
trichloroethane use can be attributed to the need to replace an otherwise
satisfactory dry cleaning machine.  The majority of dry cleaning businesses
are small and the high capital cost involved in 'early replacement may result
in the businesses being forced to close.  For certain CFC-113 machines, one of
the HCFCs (e.g., HCFC-225) or HCFC blends discussed in section 5.3.2.3 may
prove to be a "drop-in" alternative, thereby saving the cost of early machine
replacement.  In other CFC-113 machines, extensive and costly (approximately
50 percent of replacement cost) modifications to accommodate an HCFC or HCFC
blend may be possible.  For machines using 1,1,1-trichloroethane, a
modification of the energy balance may allow a change to perchloroethylene.  A
switch to flammable petroleum or hydrocarbon solvents will require-extensive
modifications or the purchase of new equipment to provide adequate safety
precautions needed because of the flammability of the solvents.
5.5   ENVIRONMENTAL AND ENERGY CONSIDERATIONS

      The solvent efficiency of the current generation of hermetically  sealed
perchloroethylene dry cleaning machines not only reduces emissions but  also


                    * 1994 UNEP SOLVENTS, COATINGS. AND ADHESIVES REPORT *
                                     5-10

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enables the solvent  to be continuously  recycled.  The machines  have  introduced
a number of features which reduce  the amount  of  solvent being used and  which
achieve solvent losses of less  than one percent  of  load weight  (equivalent  to
0.2 to 0.5 kg/g-m2 of basket cross-sectional area of dry cleaning).  Such
technology, however, has a significant  impact on machine cost,  although the
initial capital outlay'is offset by savings in perchloroethylene,  energy, and
consumption of cooling water  (Clark, 1991a).

      These new features include the following systems:

      •     carbon adsorption
      •     disc filtration
      •     heat pump technology
      •     HCFCs.

      Carbon Adsorption

      For many years, carbon adsorption systems  which adsorb solvent vapour
from air prior to discharge into the atmosphere  have been  available.  They
have usually been free standing and used  in connection with the larger
industrial machines.  This technology has now been  modified to  enable
adsorption'units to be built into  smaller,machines.  Air from the  cage  at the
end of the drying cycle is passed  through the adsorption unit prior to  opening
the cage door for unloading.  The  cage  door can  be  interlocked  to  prevent '
opening until solvent concentration has been reduced to a  pre-determined
level.

      Disc Filtration

      This method of removing the  insoluble soil from cleaning  solvent  is
gaining much support.  When a series of fine  (less  than 30 micron  mesh)
polyester disc filters are used, still  residues  are greatly reduced and the
need for filter cartridges is eliminated.  This-method of  filtration,
therefore, reduces the amount and  cost  of waste  disposal,  eliminates solvent
losses associated with the changing of  cartridges,  and saves the cost of
cartridges or other filtration  media such as powder.'  .

      Heat Pump Technology

      With heat pump technology, the heat generated by the warm side of
refrigeration units is used to  reduce the energy levels required for garment
drying and/or to preheat .solvent awaiting distillation.

      HCFCs                                           .

      If proven dry cleaning systems for HCFCs or HCFC blends become
available, the lower boiling points of  these  solvents may  further  reduce
energy use.  Although the ODPs  of  HCFCs are lower than those of
chlorofluorocarbons  (CFCs), they are not  zero, and  special recovery systems
will be needed to minimize solvent emissions.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT * .
                                      5-11

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5.6   POTENTIAL GLOBAL REDUCTION OF CFG-113 AND 1.1.1-TRICHLOROETHANE USE  IN
      THE DRY CLEANING INDUSTRY

      Reductions in CFC-113 and 1,1,1-trichloroethane solvent losses from  dry
cleaning uses are possible to achieve using currently commercially available
equipment and cleaners.    .                     •

      Long-term reductions in 1,1,1-trichloroethane and CFC-113 use will occur
as the capital stock of machines turns over to new machines that  do not use
these solvents.  Perchloroethylene, in most cases, is the logical replacement,
although it is not suitable for cleaning about 5 percent of the fabrics and
trims that now can be cleaned with CFC-113.

      Proven HCFC systems may emerge in which specialized cleaning
requirements can be met.  In addition, as  the concern over the human health
effects of perchloroethylene becomes of greater concern and is addressed by
increasingly stringent emissions reduction requirements, other alternatives
are likely to gain larger market shares in the dry cleaning industry.

      Reductions arising from relocation of 1,1,1-trichloroethane or CFC-113
machines to centralized facilities are unlikely to be significant as it is
difficult to justify the large investment  required for such a move when viewed
against a phaseout schedule.  The solvent  reduction benefits from centralized
facilities may be more fully realized with perchloroethylene or the other
alternatives described as companies replace machines using CFC-113 arid 1,1,1-
trichloroethane.

      The Committee consensus is that no CFC-113 or 1,1,1-trichloroethane
should be necessary in the dry cleaning industry  in developed countries.by the
year 1996.  CFC-113 and 1,1,1-trichloroethane use can be largely  eliminated
through the use of currently available alternative solvents, such as
perchloroethylene.  Furthermore, the Committee warns garment manufacturers
that clothing or other textile products that can only be cleaned  in CFC-113
may, at some future date, no longer be able to be cleaned.  As a precaution,
in the event that HCFC substitutes do not  become available, garment
manufacturers are advised to ensure that fabrics, trimmings, and  interlinings
are suitable for dry cleaning in perchloroethylene.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     5-12

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                                   CHAPTER 6

                            ADHESIVES APPLICATIONS
6.1   BACKGROUND          .                            '

      1,1,1-Trichloroethane is used as an adhesive solvent because it is non-
flammable,  dries rapidly, does not contribute to local air pollution, and
performs well in many applications, particularly foam bonding.  The use of
1,1,1-trichloroethane in these applications has diminished due to the
implementation of the Montreal Protocol.  However, in 1989 40-50 thousand
tonnes of the chemical were used in adhesive applications in  the U.S., Western
Europe, and Japan (Chem Systems, 1989).  As CFC-113 is not used in adhesives
it is not discussed further in this section.

      A partial list of applications where 1,1,1-trichloroethane adhesives are
used includes:

            packaging;
            non-rigid bonding;
            construction;
            .tapes;
            rigid bonding;
            transportation; and
            consumer adhesives.

      This section provides a summary of 1,1,1-trichloroethane use in
adhesives.   Section 6.2 discusses the physical properties of  1,1,1-
trichloroethane that make it attractive for adhesives use and gives examples
of its use.  Section 6.3 discusses a number of alternatives for reducing or
replacing 1,1,1-trichloroethane in adhesives, and Section 6.4 compares the
costs of these alternatives.  Section 6.5 discusses the environmental and
energy considerations of alternatives. Section 6.6 presents potential global
reduction of 1,1,I-trichloroethane in the adhesives industry.  Finally,
Section 6.7 discusses the suitability of alternatives-for developing countries
and small quantity users.
6.2   1.1.1-TRICHLOROETHANE USE IN ADHESIVES APPLICATIONS

      1,1,1-trichloroethane has several physical characteristics that provide
desirable performance properties, for adhesive applications.  It has been used
for many years in contact bond adhesives because it offers similar performance
characteristics to the flammable solvent-based adhesives it replaced and.yet
is not flammable.  In particular, it has found wide use in bonding decorative
laminates to substrates such as particle board and plywood (Dawnkaski 1991).
In general, 1,1,1-trichloroethane has been used when:    •
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

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      •     a solvent-based adhesive  is  desired  for  rapid drying time and high
            film strength, and either flammability is  a consideration or the
            use of volatile organic compounds  (VOCs)  is restricted;  and

      •     bonding certain substrates,  such as  foam,  plastic,  or wood.

      Table VI-1 presents physical properties  of 1,1,1-trichloroethane and
selected conventional solvents used in adhesives.  Of  particular note is that
1,1,1-trichloroethane (and methylene  chloride) has no  flash point.1   The
other conventional solvents listed in the  table  have  low flash  points,  low
explosion limits, and are considered  to  be flammable  solvents.

      1,1,1-trichloroethane also displays  low  water  affinity.   Only  0.05 grams
of  1,1,1-trichloroethane can be dissolved  in 100 grams of- water at 25°C.   It
is, therefore, used as a coalesceht in some water-based adhesive systems.
1,1,1-trichloroethane evaporates faster  than other solvents used in  adhesive
formulations, which allows increased  throughput  in applications where drying
time contributes to the overall process  yield  (e.g.,  in pressure-sensitive
tape manufacturing).  The density of  chlorinated solvents,  such as 1,1,1-
trichloroethane, is greater than that of conventional  solvents  used  in
adhesives, and the solids/viscosity relationship of  adhesives diluted with
chlorinated solvents is different from those diluted with conventional
solvents.  When selecting solvent alternatives,  these  differences are taken
into account with regard to application  cylinders, machine speeds, and so  on.

      1,1,1-trichloroethane has a mid-range solvency when compared to
conventional .adhesive solvents.  .The  chemical  is an  active solvent for alkyl,
acrylic, chlorinated rubbers and many phenolic resins  and a diluent  for
nitrocellulose, vinyl, and epoxy resins  (Dow 1984).  1,1,l-.Trichloroethane can
be mixed with other solvents to adapt its  solubility strength to the needs of
a specific resin system.  This task is usually performed by the adhesive
formulator who customises solvent blends to meet specific solubility needs.

      In the U.S., 1,1,1-trichloroethane is exempt from volatile organic
compound (VOC) regulations in most states,  which provided an incentive for
some adhesive manufacturers and their customers  to use the solvent in place of
VOC solvents (Dawnkaski 1991).  As an example, 1,1,1-trichloroethane has been
used as a replacement for organic solvents in  the following applications (UNEP
1989):

      •     manufacture 'of styrene-butadiene latex adhesives;
      •     formulation of polyurethane-adhesives;
      •     replacing extremely flammable  solvents in  pressure-sensitive tapes
            and labels, and in industrial  and  consumer adhesives;
      •     'Substituting flammable solvents in PVC flooring adhesives;  and
      •     replacing ethyl acetate solvents in  laminating adhesives used  in
            packaging.

      In general, 1,1,1-trichloroethane  is used  as active solvent in solvent-
borne adhesives and as a diluent in water-borne  adhesives.   Solvent  borne
adhesives containing 1,1,1-trichloroethane are primarily contact adhesives and
     1  Flash point temperature is the lowest temperature at which vapours
above a volatile combustible substance  ignite  in air when  exposed  to  flame.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

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         Table  VI-1.   PHYSICAL PROPERTIES OF COMMON  ADHESIVE SOLVENTS
      Solvent
                       Flash Point.
                        Open Cup
Flammable Limit
    in Air
25°C (Volume %)
Upper     Lower
         Water
       Soluble in     Kg/
      lOOg Solvent   Liter
          (g)         20°C
1,1,1-Trichloroethane      NFa

Methylene  Chloride         NF

Toluene                    7.22

n-Hexane                 -27.8

Methyl Ethyl  Ketone      -5.6

Ethyl Acetate            -2.2.
  12.5

  22.0 .

   7.0  .

   6.9

  11.5

  11.0
 7.5

14.0

 1.3

 1.25

 1.81

 2.25
 0.05

 0.17

 0.05

 0.01

11.80

 3.3
1.314

1.316

0.870

0.678

0..804

0.900
a NF = No Flash Point.

Source:  Dow  1984.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *

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spray adhesives used where good "green bond," or initial bond, is desired, as
in the manufacture of foam cushioned furniture or plastic laminated
countertops.   The primary binders in these adhesives are rubbers of various
kinds, including natural rubber, neoprene, chloroprene, and styrene-butadiene
rubber.  Acrylic binders are also used.  Adhesive grades applied by extrusion
or spraying have dry solids contents of less than 15 percent, while other
grades are between 15 and 30 percent.  Table VI-2 shows specific binding
substances (i.e., adhesive type) where 1,1,1-trichloroethane  is used.

      In assembling foam padded furniture, for example, a thin film of
adhesive is applied to the two surfaces being joined.  When the foam padding
is applied to the frame, the adhesive bonds immediately.  The adhesive joint
must then hold without adhesive or solvent migrating into the foam material
and ruining it.  In other words, the tack, or "stickiness", of the adhesive
must decline quickly.  The 'time between application and the last moment for
assembly (when the tack disappears) is called the "open assembly time".  The
solvent-based rubber adhesives'have good properties in these  respects, with
good green bond and a short open assembly time.

      Two paths are available for solvent reduction in adhesives; established
technologies and emerging technologies.  Established technologies include
other solvent-based adhesives, water-based adhesives, hot melt systems, and
solvent recovery systems in continuous operations.  Emerging  technologies
include radiation cured adhesives, "high solids" adhesives, powders, and
reactive liquids.  These technologies are discussed .in further detail below.
6.3   ALTERNATIVES FOR REDUCING OR REPLACING 1.1.1-TRICHLOROETHANE USE

      6.3.1 Other Solvent-Based Adhesives

      The rubber binders used in 1,1,1-trichloroethane adhesives are  soluble
in other solvents, such as acetone, ethyl acetate, -heptane, and toluene.
Although there has been a general trend in the U.S. arid Western European
adhesives industries to replace organic solvent-based adhesives with  solvent-
free types,  one alternative is to return to earlier solvent formulations.
According to one market survey conducted in the U.S., volatile organic
compound (VOC) regulations provided the initial impetus for moving away from
solvent-based technologies.  However, for some industry sectors, such as
tapes, this shift would continue in the absence of regulations because
alternative technologies are more competitive on a cost and performance basis
(Ellerhorst 1982).  The use of solvent-diluted (as opposed to solvent-based)
adhesives has also been declining for economic reasons (Kimel 1988).

      The use of solvent-based adhesives is costly because they require flame
proof equipment and extraction systems (6'Driscoll 1988, Johnson -1991).  The
premises and apparatus must be designed fire-safe in terms of both sparking
and static electricity.  In many cases it is necessary to use robots  in closed
booths,  which means large-scale use is required for cost effectiveness.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                   Table VI-2.   USES OF 1,1,1-TRICHLOROETHANE
      Use Sector
Binding Substance
      As Active  Solvent in Solvent-Borne
      Adhesives
Styrene-Butadiene Rubber  (SBR)
Neoprene
Natural Rubber
Rubber Cement
Other
      As a Diluent  or  Coalescent in Water-
      Bo rne Adhesives3
a No data is currently available  on the specific binding systems that employ
1,1,1-trichloroethane  as  a diluent and or coalescent.

Source:  Based  on  Skeist  1987.
                      1'994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      6.3.2 Water-Based Adhesives

      Some adhesives use water, in lieu of organic solvents, as the primary
solvent.  A water-based adhesive can be a solution, a latex, or an emulsion.
Solutions are made from materials that are soluble in neutral or alkaline
water; most natural adhesives are water solutions.  Latexes are stable
dispersions of solid polymeric material in an essentially aqueous medium
(Landrock 1985),  while emulsions are stable dispersions of immiscible liquids.
Emulsions usually appear milky white in the liquid state but dry to a clear
film.  In industry, the terms latex and emulsion are generally synonymous.
Latex adhesives are more likely to replace solvent-based adhesives than
solution adhesives because their synthetic binders provide more versatility
and higher performance (Landrock 1985).  Latexes, however, require more
extensive formulation because they are produced from polymers not originally
designed for use as adhesives.

      The binding substances that are candidates for water-borne adhesives
include:, natural substances, including natural rubber; synthetic elastomers
such as styrene butadiene rubber, neoprene, and isoprene; vinyl resins such as
polyvinyl acetate (PVAc) and polyvinyl chloride (PVC); acrylics; and epoxies
(Landrock 1985).   Some of these binding substances require additional
formulation and additives like emulsifiers, surfactants, or additional resins.
Water-based binding substances use the traditional methods for adhesive
application.  These include brush, .spray, roll coat, curtain, flow, and knife
coat  (Landrock 1985).

      Recent literature on water-based adhesives suggests that there is still
much debate about the overall effectiveness of water-based, adhesives for many.
end uses.  In general, water-based adhesives show good durability, water
resistance, and adhesion to a wide variety of substrates, especially in the
area of nonporous to porous bonding (Chao and Hernisch 1986).  Problems still
exist in the bonding of non-porous to non-porous substrates because water is
difficult to evaporate from such substrates.  In addition water-based
adhesives are not suitable for non-structural bonding of rubbers and many
plastics.                           •

      Water-based adhesives can bond moist surfaces better than solvent-based
adhesives.  One inherent advantage of water emulsions is that viscosity is
independent of molecular weight of the resin (Fries 1984).  The higher initial
molecular weight polymer provides greater internal cohesive strength to the
freshly made bond.  This initial, green bond is important to avoid uneven bond
stress and blisters in laminating applications (Fries 1981 and Fries 1984).
Poor initial bond strength has been a criticism of low molecular weight water-
borne adhesives.   Unlike solvent-borne and hot melt adhesives, there are no
restrictions on the initial molecular weight of the resin for water emulsions'.

      The direct replacement of solvents.by water is not feasible in all
sectors.  Selecting water as the vehicle in adhesives demands totally new
concepts in raw materials and formulation as discussed above.  Water-based
adhesives often require special handling in manufacturing, storage, and
application.  They must be kept from freezing during shipment and storage
(Landrock 1985, Dawnkaski 1991).  Problems with corrosion require that all
storage and transfer pipes be corrosion-resistant.  Some manufacturers,
however, maintain that corrosion is-not a factor if additives which prevent
corrosion are included in the formulation, and one set of laboratory tests


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                                      6-6

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found water-borne adhesives not to be more prone to corrosion than solvent-
borne adhesives (Manino 1981).  The problem has not been resolved
conclusively; more research and development is needed in this area (Johnson
1991).  Another problem with  storing water-based adhesives is that agitation
is needed to maintain consistency of the dispersed materials in the adhesive
solution.  Yet.agitation can  cause foaming, and anti-foaming agents compromise
adhesive bond performance.

      Water-based adhesives reportedly have other performance disadvantages
when compared with solvent-based adhesives.  During application, water-based
adhesives do not "wet" surfaces as well as their solvent-based counterparts
due to water's inherent polarity and high surface tension (Dawnkaski 1991).
Minor contamination of the surface (e.g., oil, mould release, fingerprints)
can lead to bonding problems.2  Water-based adhesives do not have the
versatility of application provided by solvent-based adhesives (Johnson 1991).
Although polar substrates, such as natural rubber, bond well with water-borne
adhesives, nonpolar elastomer substrates, such as ethylene propylene
copolymers, are difficult to'bond (Manino 1981).  Silicones and
fluoroelastomers provide a greater challenge, and water-borne adhesives still
cannot compete with solvent-borne systems in these areas (Manino 1981).
Finally, spray application of water-based adhesives can be especially
difficult due to the ease with which water- carried adhesives are atomized.
Spray application results in  a fine mist that can travel to all areas of a
shop, coating persons and objects with a thin coating of adhesive (Dawnkaski
1991).                .   .

      6.3.3 Hot Melt Adhesives

      The Committee D-14 of the American Society for Testing and Materials
(ASTM) defines a hot melt adhesive as one that is applied in a molten state
and forms a bond upon cooling to a solid state (Fullhart and Mottershead
1980).  Hot melts are primarily 100 percent solids thermoplastic bonding
materials that achieve a solid state and resultant strength upon cooling.  The
major applications of hot melt adhesives are bookbinding, packaging, textiles,
and product assembly, including construction glazing and automotive door panel
and carpet installation (Fullhart and Mottershead 1980).  Application methods
include melt-reservoir and pressure-feed systems (Landrock 1985).  The binding
substances that provide the foundation for hot melt adhesives are ethylene
vinyl acetate  (EVAc) and other polyolefin resins; polyamide (or nylon) and
polyester resins; polyester/amide resin alloys; and thermoplastic elastomers
(Landrock 1985).  Foamable hot melts (e.g., polyethylene) form a superior bond
with metals, plastics and paper (Landrock 1985).

      Although earlier hot melt pressure sensitive adhesives (PSAs) had
unacceptable colour retention and UV resistance, present hot melt PSAs are
clear and UV resistant (Maletsky and Villa 1984).  Hot melt PSAs now compete
with water-based acrylics in  outdoor applications (Maletsky and Villa 1984).
They have been used on 'paper  labels for indoor applications since 1978.
     2  A solvent-based primer can boost performance by ensuring a clean
substrate for the water-based adhesive.  A primer uses less than half as much
solvent as solvent-borne adhesives.   1,1,1-Trichloroethane has been used as a
primer to degrease many substrates  (Landrock  1985).

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES'REPORT *
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      Hot melts are, however, limited  in several key performance
characteristics.  They have poor specific adhesion  to a number  of  substrates,
creep under load over time and at high temperatures, have  limited  strength,
and limited heat resistance (Landrock  1985).  A specific hot melt  acrylic used
for pressure-sensitive applications has poor  tack for many applications
(Lipiec 1982). . Room temperature shear resistance and elevated  temperature
shear resistance are also, deficient in hot melt acrylic PSAs  (Lipiec  1982).

      6.3.4  Radiation Cured Adhesives
            /                 (                                            N
      Radiation curing is a production technique for drying and curing
adhesives through the use of radiant energy such as ultraviolet (UV), infrared
(IR), electron beam (EB), gamma, arid x-rays.  In essence,  radiant  energy
becomes chemical energy  in the forming of the adhesive bond.  The  binding
agents that can be cured with radiant  energy  are acrylics, epoxies, urethanes,
anaerobic adhesives, and polyester resins (Adhesives Age 1988).  Pressure-
sensitive or 100 percent non-volatile  formulations  of adhesives are applied by
conventional techniques  betwe'en one or two plastic  films and then  cured by
exposure to radiant energy (Chemical Week 1987).  Application areas include
electronics, communications, consumer  products, transportation, packaging, and
medical and dental uses  (Bluestein 1982).  Radiation cured adhesives  are
especially well adapted  for pressure sensitive tapes.  One drawback is that
adhesive curing is only  possible in the "line of sight" of the  radiant energy.
Pressure-sensitive tapes are another major application of  radiation cured
adhesives.  High growth  is anticipated for UV and EB cured adhesives.  It is
not evident whether UV methods are particularly suited to  bonding  opaque
substrates.

      ,6.3.5 High Solids  Adhesives

      One way to lower volatile organic compound (VOC) emissions when using
solvent-based adhesives  is to increase the percent  solids  in the formulation.
In the specific example  of polyester urethane laminating adhesives, high
solids/low solvent adhesives are an alternative to'  solvent-borne adhesive
systems.  Using the existing technology for polyesters and polyester  urethane
systems, high solids have been very successful in laminating uses  (Bentley
1983.).  One manufacturer supplies a 68.5 percent solids polyester  urethane
laminating adhesive which meets VOC regulations by  lowering the amount of
solvent used (Wood 1984).  High solids adhesives have good performance
characteristics, including initial bond strength, comparable to that  of 30
percent solids adhesives in medium and high demand  applications and can be
applied using existing equipment at normal line speeds with minor
modifications.(Wood 1984).

      In other application areas, such as bonding rubber assemblies,  high
solids adhesives have not been as successful.  For bonding rubber  assemblies,
high solids adhesive films are too thick, which results in limited versatility
and generally poor performance (Manino 1981).  In general, high solids
adhesives cost more per  pound since they do not contain the nonreactive
solvent as a diluent.  However, advanced products consisting of a  100 percent
solid adhesive and a liquid primer are now commonly used in critical
structural bonding applications, such  as aircraft wings.   The 100  percent
solids structural adhesives generally  require refrigeration, shelf life
control, and training or practice in application.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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       6.3.6 Powders

       One-part epoxies,  urethanes,  and natural resins are often supplied as
 powders that require heat to cure (Frisch and Xiao 1988).   Powders are only
-used for non-pressure-sensitive applications.  They are generally applied in
 three ways:,  by sifting the powder onto pre-heated substrates, by dipping a
 preheated substrate into the powder,  and by melting the powder into a paste or
 liquid and applying it by conventional means (Landrock 1985).   One advantage
 of the powder form is that no mixing or metering is necessary.  However,
 powders must be refrigerated to maximise shelf life (Landrock 1985).   No data
 are currently available comparing performance and cost with solvent-borne
 adhesives.

       6.3.7 Non-Volatile Solids and Liquids and Reactive Liquids .

       Moisture cure adhesives and reactive liquids can be  applied as  100
 percent non-volatile solid and liquid systems.   These adhesives are composed
 entirely of binding substances, modifiers, and fillers (i.e.,  they have no  .
 carrier or solvent).   Moisture cure adhesives cure upon exposure to the
 humidity in the ambient air; this type of adhesive requires application in a
 humid environment and might not work well in dry climates.   Moisture  cure
 adhesives are available in 100 percent non-volatile liquids and solids,  hot'
 melts,  solvent-borne formulations,  and other technologies  (Frisch and Xiao
 1988) .   Moisture-cured silicone-based adhesives include at least two  specific
 types,  methoxy-cured and acetoxy-cured.   These systems use water in the
 atmosphere to react in the adhesive reaction.  The by-products are  small
 quantities of either methanol or acetic acid.

       The 100 percent non-volatile  moisture cure systems are of interest
 because they offer another alternative to the solvent-based systems;   The two
 primary binding substances used in moisture cure adhesives are isocyanates and
 polyurethanes (D'Autilio 1983). They are available as single and multiple
 component adhesives.   The two-part system physically separates the  binding
 agent from the curing agent during storage.  Although the  adhesive  requires
 metering and mixing to cure, the two-part system has a longer  shelf life.  The
 two-component system also achieves  higher performance.   A  two-component
 solvent-free" isocyanate adhesive that does not require moisture to  cure nor
 precise metering has appeared on the market.  A thin coat  of one component is .
 applied to one part and a thin coat of the other to the second part.   The two
 are brought together and form a rapid and strong bond in a few seconds.   As
 the bond does not require oxygen.to form (i.e., is anaerobic), isocyanate
 adhesives are useful.for joining metallic and other non-porous parts.   Tests
 have shown,  however, .that the electrical properties of the adhesive exclude it
 from electronics applications,  such as bonding surface mounted components to
 substrates  prior to wave soldering.

       Some two-component adhesives  use reactive solvents which form part of
.the cured mass and thus do not depend on evaporation.   In  use, one  solution
 consisting of an elastomer colloidally dispersed in a monomer  is cured by a
 second solution through a free radical chemical polymerisation, thereby
 creating the bond (Prane 1980).  The binding substances for reactive  liquid
 adhesive systems include epoxies, urethanes, polyesters, silicones,
 polysulphides,  acrylics, modified phenolics,' and resin compounds (Prane 1980).
 Reactive liquids are used for high performance structural  applications.
 Application methods are similar to those used in contact adhesives, namely,


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       6-9    •

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brush, roller, or spray  (Prane 1980).  No  information  is  currently  available
on the relative performance attributes of  this emerging technology.
6.4   COSTS OF ALTERNATIVES

      Substitution costs for the established alternative  technologies  are  in
most cases driven by the raw material  costs and  capital investments  required
to implement these technologies.  Research and development  resources are also
required to develop, and test alternative  technologies  - 'water-based  adhesives,
hot melt adhesives, and solvent recovery  - for specific adhesive  systems.   The
cost of switching to an alternative  solvent is highly  dependent on whether or
not the solvent  is a VOC since VOC emission and  worker safety  regulations  may
•require installing expensive ventilation  and vapour  recovery equipment.

      Converting to water-based solvents  allows  adhesives users to reduce
their inventory  of solvents.  Water-based adhesives  require stainless  steel
application equipment, hoses, stirrers, etc., and  there may be significant
conversion costs.  Water-based adhesives  clean easily  during application,  but
the rinse water  should be properly disposed of or  recycled.

      Although hot melt adhesives are  more expensive per  unit  of  formulated
weight, in many  applications their use leads to  reduced overall costs.  The
conversion to a  hot melt system requires  installing  new,  moderately  expensive
equipment.  The  capital costs of conversions are offset by  saving space and
energy from the  use of automated equipment, lowered  raw material  costs, and
increased productivity (Lipiec 1982).   Hot melts can be applied faster and
more efficiently than .water-based adhesives because  there is no delay  for
evaporation (Kimel 1988).  Since hot melt formulations contain 100 percent
solids, they can be slightly more expensive when shipment in refrigerated
trucks is required.

      Prior to curing, radiation cured adhesives have  a longer shelf life  than
most adhesives (Bluestein 1982).  Their use leads  to production of a more
reliable product, lower rejection rates and labour costs, and  reduced  cleanup
and inspection times (Moreau 1988).  Radiation cured adhesives are an  option
for new production facilities due to the  simpler,  .space-'saving equipment
(Bluestein 1982).  Among the radiation curable technologies, UV and  EB curing
have separate applications.  UV curing is more cost  effective  for smaller
applications, whereas EB curing is better adapted  for  large scale operations.

      Radiation  cured adhesives have some disadvantages.  Existing equipment
cannot be used for this type of adhesive  without the addition  of  a cure unit
(Bluestein 1982)..  In addition, the  applications are limited to "line  of
sight" for radiation cured adhesives.

      As mentioned above, high solids  adhesives  typically cost more  but
outperform their solvent-borne counterparts at lower solids levels.  This
technology development is ongoing.              .
6.5   ENVIRONMENTAL AND ENERGY  CONSIDERATIONS

      There are a number of environmental  and  energy  implications  to  replacing
1,1,1-trichloroethane-based adhesives with alternatives.   Returning to the  use


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT  *
                                     6-10

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of other solvent-based adhesives will affect local air pollution and worker
safety unless precautions are taken.  VOC solvents contribute  to the formation
of tropospheric ozone and their use  is restricted in many  localities;  their
flammability requires the installation of special equipment  to minimize  the
danger from fire or explosion.  These concerns were the  incentive  to move  to
the use of 1,1,1-trichloroethane initially.

      Water-based adhesives have a number of characteristics that  make them
attractive substitutes.  As they contain no volatile organic solvents, water-
based adhesives do not. contribute to local smog problems and are nonflammable.
They can, however, emit small quantities of hydrocarbons,  ammonia, and
emulsion-stabilising substances.  In ideal situations, these pollutants  can be
removed to some extent using, for example, wet scrubbers.

      From the energy perspective, drying ovens used for solvent-based systems
generally are adequate to handle water-based adhesives.  Increased air flow
rates and longer oven bake cycle times are required to evaporate water,
however, so process flow can be affected and energy usage  may  increase.

      Hot melt adhesives also have several environmental and energy
advantages.  As no solvents are used in hot melts, they  do not contribute  to
smog formation.  In part because no  drying oven is needed, hot melt pressure
sensitive adhesives require far less energy to process than most other
adhesive types (Maletsky and Villa 1981).  The percent solids  in the
formulation directly influences the  amount of energy saved;  this percentage
varies depending on the application.  One drawback .of hot  melts is that  the
presence of hot equipment may be a danger to workers (Fullhart and Mottershead
1980).

      The advantages of radiation cured adhesives are low  energy costs and
reduced emission of waste effluents  and polluting gases  and  liquids.

      Both moisture cure adhesives and reactive liquids  achieve compliance
with VOC regulations because they contain no solvents.   Moisture cure  systems
also need no driers, and thus save energy (D'Autilio 1983).  The application
equipment is more compact than that  of solvent-based systems,  but  moisture
cure adhesives cannot use existing solvent application equipment (Morphy et
al. 1987).  Moisture-cured adhesives and sealants, especially  silicones,
evolve small amounts of methanol, acetic acid, or other  products of the
moisture reaction.  There is some concern that the catalysts used  with
reactive liquid systems are,, in some cases, hazardous or toxic substances
(Dawnkaski 1991).      .       '
6.6   POTENTIAL  GLOBAL REDUCTION  OF 1.1.1-TRICHLOROETHANE-USE IN THE  ADHESIVES
      INDUSTRY

      There  is limited data, on the  worldwide  market  for  adhesives;  however,
information  is available  on the U.S.,  European,  and  Japanese  markets.   The
1983 adhesive demand in the U.S.  and Europe was  4,900 million dry formulated
pounds and it grew  at an  annual rate of  3.9 percent  to approximately  5,900
.million pounds in 1988 (Broxterman  1988).  The U.S.  portion of this demand  is
significantly larger than the  European portion,  representing  about 4,600
million pounds,  or  75 to  80 percent of the estimated demand in 1988.   The
Japanese market  is  considered  roughly equivalent to  the  European market,


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      6-11

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together consuming 1,300 million dry pounds  of  adhesives  in 1987 (O'Driscoll
1988).  Approximately 40-50 thousand tonnes  of  1,1,1-trichloroethane was used
in adhesives in these countries in 1985  (ICF 1989).   Table  VI-3 shows the U.S.
and European adhesive demand by segment.       •     ~

      As mentioned above, there has been a worldwide  trend  away from the use
of solvent-based adhesives.  The cost  savings associated  with water-borne and
hot melt systems are such that this trend would continue  even in the absence
of the Montreal Protocol's provisions.
6.7   SUITABILITY OF ALTERNATIVES FOR DEVELOPING  COUNTRIES  AND SMALL QUANTITY
      USERS

      Most established alternatives  to  1,1,1-trichloroethane  solvent adhesives
can be used in developing countries  and by  small  quantity users.   Some
systems, hot melts for example, require a larger  capital  investment for
equipment, although the cost per application  compares  favourably.   The cost of
converting to an alternative adhesive system  may  be  a  hurdle  in some
situations.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      6-12

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Table VI-3.  ESTIMATED U.S.  AND EUROPEAN ADHESIVE DEMAND BY SEGMENTS  -- 1988
Market Segment
Packaging
Non-Rigid Bonding
Construction
Tapes
Rigid Bonding
Transportation
Consumer
TOTAL
Estimated 1988
U.S. and Western
Millions of
Dry Formulated Pounds
2,500
1,100
1,000
500
400
300
•" IPO
5,900
Demand
Europe
Percent
42.4%
18,6 .
16.9
8.5
i '
6.8
5.1
1.7
100.0
Source:   Based on Broxterman 1985.
                     * 1994 UNEP SOLVENTS', COATINGS, AND ADHESIVES REPORT *
                                        6-13

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                                   CHAPTER 7

                         COATINGS  AND INKS APPLICATIONS
7.1   BACKGROUND

      It  is estimated  that  48  percent  of  the  U.S.  coatings  market  in 1986  was
based on  solvent-based formulations.   This  represents  solvent  use  in coatings
in 1989 of 1.7 million metric  tons,  of which  only  1.2  percent  or 21,800  tonnes
(for Europe, North America,  and Japan  in  1989)  (ECSA,  HSIA,  JAHCS)  was 1,1,1-
trichloroethane (Chem  Systems, 1989).   Water-based coatings  accounted for  12
percent of the market;  high solids,  11.5  percent;  two  part-systems,  12
percent;  emulsions,  10 percent; powder coatings, 6 percent;  and ultraviolet
light/electron beam  (UV/EB)  cured  coatings, 1.5 percent  of  the market.   In
addition, there are  solvent-recovery and  low-emissions coating application
methods,  such as dipping, flow, and  curtain coating that are alternatives  to
the use of spray coating.           .     ,                            .      >   '
7.2   CFC-113 .AND 1.1.1-TRICHLOROETHANE USE  IN  COATINGS AND  INKS APPLICATIONS

      1,1,1-Trichloroethane  is used by manufacturers, printers, and  users  of
protective and decorative coatings and inks.  CFC-113 use  in the production of
coatings or inks is  negligible. • Therefore,  this  chapter will focus,  on  the use
of 1,1,1-trichloroethane in  coatings and  inks applications.   In coatings,
1,1,1-trichloroethane  is used alone or combined with other solvents  to
solubilize the binding substance which is usually composed of resin  systems
such as alkyd, acrylic, vinyl, polyurethane, silicone, and nitrocellulose
resin.  In addition  to its good solvency, 1,1,1 -trich'loroethane is also used
because of its nonflammability and fast evaporation rate,.   These properties
also make 1,1,1-trichloroethane a suitable thinner for spray coating
applications as well as an excellent solvent for  ink applications.   Inks are
used to print items  ranging  from wallpaper to dog food bags  to beverage
bottles and cartons.   Many of these uses  involve  the application of  coloured
ink to a film (or laminate)  in the flexible  packaging industry.

      Although the overall market for coatings  and inks in the U.S.  showed
relatively slow growth in the 1980s (approximately 1 percent according  to  U.S.
Industrial Outlook 1989) , the trend in the late 1980s to replace volatile
organic compound (VOC) solvents in coatings  and inks formulations with  1,1,1-
trichloroethane resulted in  a significant increase in 1,1,1-trichloroethane
demand.   However, this growth in usage of 1,1,1-trichloroethane has  reversed
in recent years because of the addition of 1,1,1-trichloroethane to  the list
of substances controlled under the Montreal  Protocol.
     1   In the .U.S. 1,1,1-trichloroethane is also -used frequently because of
its non-volatile-organic compound  (VOC)  status.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 7.3   ALTERNATIVES FOR REDUCING OR REPLACING CFC-113 AND  1.1.1-TRICHLOROETHANE
      USE

      The use of 1,1,1-trichloroethane  in the production  of coatings  and  inks
 has been reduced in  the early 1990s through more extensive  use  of  several o.f
 the aforementioned formulations, specifically water-based coatings and  inks,
 high-solids coatings, and powder coatings.  Because these alternative
 formulations function as well as 1,1,1-trichloroethane-based  formulations in
 most applications, the use of these alternative coatings  and  inks  results only
 in a difference in handling procedures.  These differences  should  manifest
 themselves predominantly in storage and distribution as many  of these
 alternatives will be more flammable than their 1,1,1-trichloroethane-based
 counterparts (SNV 1990a).

      7.3.1 Water-based Coatings and Inks

      Some coatings  contain water rather than conventional  solvents.  They can
 be applied using a variety of methods,  including:  dipping, flow coating,
 conventional air and airless atomizing, air and airless electrostatic
 spraying, rotating disks and bells, rolling, continuous coating, centrifugal
 coating, and tumbling.  Recent advances in water-based coating  technology have
 improved the dry-time, durability, stability, adhesion, and application of
 water-based coatings.  Primary uses of  these coatings include furniture,
 electronics in automobiles, aluminum siding, hardboard, metal containers,
 appliances, structured steel, and heavy equipment.  In some water-based
 coatings, standard solvents are added for ease of application,  but even these
 contain much less solvent than conventional coatings and  meet VOC  limits  since
 the primary solvent  is water.  A typical formulation blending water with
 conventional solvents might contain 80  parts water to 20  parts  solvent  by
 volume (UNEP 1992).

       Water-based inks for flexographic and rotogravure  laminates have been
 successfully developed and have overcome technical hurdles  such as substrate
 wetting, adhesion,  colour stability, and-productivity.  Solvent-based inks
 have good wetting properties because of the low surface tension of most
 solvents.  However, water has a relatively high surface tension as compared
 with most solvents and it requires the  use of co-solvents to  lower the  surface
 tension to enable the wetting of treated surfaces.  A mixture that is 80  parts
 water and 20 parts alcohol and ethyl acetate by volume will achieve an
 effective surface tension.  The ability of the. water-based  ink  to  adhere  to
 the film can be enhanced by treating the film by means of accepted methods
 such as use of primers or heat.  About  55 percent of the  flexographic inks and
 15 percent of the gravure inks used in  the U.S. in 1987 were water-based.
 Continued growth of aqueous inks has been projected by various  industry
 sources.

      7.3.2 High-Solid Coatings

      Although high-solid coatings resemble conventional  solvent coatings in
 appearance and use, high-solid coatings contain less solvent and a greater
percentage of resin.  They are applied u'sing methods similar  to those used for
water-based coatings.  High-solid coatings are currently  used for  appliances,
metal furniture,  and a variety of construction equipment.   The  finish of  high-
 solid coatings is often superior to that of solvent-based coatings, despite
                    " 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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the fact  that high-solid  coatings  require  much less  solvent than do solvent-
based coatings.

      7.3.3 Powder  Coatings

      Powder coatings  contain  the  resin  only  in powder  form and thus have  no
solvent.  They are  applied using fluidized beds,  electrostatic  spray,  and
electrostatic fluidized beds.   The object  to  be coated  is  heated above the.
powder's  melting point, so that when  the object is removed from the presence
of heat,  the resin  fuses  into  a continuous film.  The resin then hardens to
form a finish that  has excellent durability and corrosion  resistance.   While
powder coatings were first used only  for electrical  transformer covers, they
are now used in a large number of  applications,  including:

            underground pipes;                       •
            electrical components;
            concrete reinforcing bars;
           . appliances;
            automobiles;     '
            farm and lawn equipment;
            lighting fixtures;
            aluminum extrusions;
            steel shelving; and,
            some furniture.             .

      7.3.4 UV/EB-Cured Coatings and  Inks.  .

      UV/EB-cured coatings arid inks have been used in very limited
applications over the  last 20  years,  but their use has  seen a dramatic
increase  in recent  years.  Several of the  markets in which UV/EB-cured
coatings  and inks have been used more frequently  in  recent years  are
flexographic inks and  coatings, wood  furniture and cabinets, and automotive
applications.  It is estimated that the  usage of UV/EB-cured products  has
grown by  11 percent annually in North America between the  years  1988 and 1993,
and this  growth is  expected to continue  for another  five years.   Annual growth
in Europe is estimated at 5-6  percent.   Although  this growth is  expected to
slow in the future, UV/EB-curing is likely to remain popular in  niche
applications (MFC 1994b).  One business  manager for  a supplier  of these
coatings  has estimated that UV/EB  coatings' share of the worldwide  paint and
coatings  market will double over the  next  5 to 7 years  (MFC 1994a).

      There are several factors which contribute  to  the growing  popularity of
UV/EB-cured coatings and  inks.  These include:  high quality, rapid cure
times,  low energy use, small space requirements,  elimination of  some handling
problems, and reduction in emissions  of  ozone-depleting substances  and VOCs..
One major limitation to the use of UV/EB-cured coatings and inks  is outdoor
durability (MFC 1994b).   This  is an especially important consideration in
automotive applications.
7.4   ENVIRONMENTAL AND ENERGY CONSIDERATIONS

      Goods are printed or coated with solvent-based coatings and  inks  in  a
continuous process.  Once the coating or ink has been applied,  the product
passes through a drying step where the solvent is emitted  through  evaporation.


                    '• 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      7-3                  '

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Solvent recovery syr.tems  such as  carbon adsorption can be used to capture
these solvent emissions.  As  discussed earlier,  technological innovation is
overcoming the stabilization  problems which sometimes occur.

      The types of coatings and inks  described in this chapter as alternatives
to formulations containing 1,1 ,"l-trichloroethane reduce solvent emissions by
reducing or eliminating the use of conventional solvents.  Therefore,  the
environmental impacts associated with such solvent emissions are also  reduced.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      7-4

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                                   CHAPTER 8

                             AEROSOLS APPLICATIONS
8.1     BACKGROUND

      Aerosol packaging  is a popular method  for storing and dispensing
consumer and industrial  products ranging  from  insecticides to hair sprays.   In
1986, the worldwide aerosol industry produced  an estimated 6.8 billion units.
Western Europe was the largest producer,  followed by  the United  States and
Asia.  1,1,1-Trichloroethane consumption  in  aerosol applications in  the U.S.
was approximately 18,590 metric tonnes  (ICF  1989a).   It is estimated that
Western Europe and Japan consumed 12,425  and 10,790 metric tonnes of 1,1,1-
trichloroethane in 1984, respectively  (ICF 1989a).  The Aerosol  Industry of
Japan estimates that consumption of 1,1,1-trichloroethane in the Japanese
aerosol industry had dropped to 5,000 metric tonnes in 1990 (Kurita  1991b).
No data are available for the rest of  the world.  No  information is  currently
available on current chlorinated solvent  consumption  trends in Western Europe,
Japan, and the rest of the world, therefore, the discussion that follows
focuses on the U.S. market for aerosols.  The  major aerosol product  end-uses
where 1,1,1-trichloroethane is used includes automotive and industrial
products, pesticides, and household products (ICF 1989a).
8.2'  CFC-113 AND 1.1.1-TRICHLOROETHANE USE IN AEROSOL PRODUCT APPLICATIONS

      In an aerosol package, the contents are stored under pressure  in a metal
container and dispensed in a controlled manner by activating a valve.  The
continued effect of the type of propellent used, the shape of the  opening from
which the contents are expelled from the can, and the composition  of the
product determine the form in which the product  is delivered.  This  form can
range from a fine mist (the most common) to a liquid stream to a foamy lather.
In general, the components of an aerosol are the'active  ingredient,  the
solvent or carrier, and the propellant.  The active ingredient is  responsible
for the effectiveness of the product (i.e., the  ingredient that allows a
cleaner to clean); the solvent or carrier solubilizes all ingredients in the
formulation to allow for uniform dispensing of the product; and the  propellant
expels the contents from the can.

      1,1,1-Trichloroethane functions as either  an active ingredient (e.g.,
degreaser or cleaner) or as a solvent in aerosol product formulations.  1,1,•!-
Trichloroethane's high density adds to container weight  while its  high
stability translates to a long shelf li-fe.  Other properties that  make 1,1,1-
trichloroethane especially well-suited for aerosol applications are  its
nonflammability, excellent solvent properties, high evaporation rate, and
ability to generate a spray of small particle size.  Quick evaporation allows
1,1,1-trichloroethane to deliver .the active ingredient efficiently and a small
particle size results in a good spray pattern.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      Though most of the aerosol applications traditionally used 1,1,1-
trichloroethane as their solvent, there are a small number of products which
made use of CFC-113 as well.  Probably a few tens of tonnes per year of CFC-
113 were used annually in the late 1980s.  The application where CFC-113 was
most often used as a solvent is in the removal of flux from electronic
components such as printed circuit boards  (PCBs).  In these products, CFC-113
was often mixed with another chemical such as isopropyl or ethyl alcohol.
These product mixtures were often used due to the fact that they act as both
degreasers and cleaners, and leave very little residue on evaporation.

      Conformal coatings also make use of CFC-113.  These products are sprayed
on printed circuit boards and other electronic components to serve as a
sealant.  Over a wide range of temperatures, these coatings protect equipment
from environmental conditions which would normally damage the equipment.
Depending on the resin used in the coating, 1,1,1-trichloroethane is sometimes
included as well.

      Finally, CFC-113 is often used in aerosol application for contact
cleaners.  The cleaners are used as part of the routine maintenance of
electrical equipment in order to prevent malfunctions which might occur from
everyday pollutants.  Because this equipment is often cleaned while energized,
it is important that the aerosol cleaner be nonflammable, thus making CFC-113
an attractive ingredient.  Use of these cleaners helps to maintain continuity
within electrical circuits  (Chemtronics 1989).
8.3.  ALTERNATIVES FOR REDUCING OR REPLACING CFC-113 AND 1.1.1-TRICHLOROETHANE
      USE IN AEROSOL PRODUCTS

      Most aerosol products currently employing CFC-113 and 1,1,1-
trichloroethane can be reformulated with alternative compounds.  Table VIII-1
lists substitute solvents and the major product application areas.   From a-
number of properties determining product performance,  two performance factors
are considered of most importance:  flammabili.ty and density.  These factors
are also listed across the top of the table.  Except for water,  some
hydrochlorofluorocarbons (HCFCs), and non-ozone-depleting chlorinated solvents
(e.g., trichloroethylene, perchloroethylene, methylene chloride), all of the
substitute solvents currently available are more flammable  than  1,1,1-
trichloroethane.  The flammability is also a function  of the propellant;
butane and propane being more flammable than carbon dioxide,  nitrous oxide  or
the traditional CFC-ll/CFC-12 mixture.

      Alternative solvents currently exist for virtually all aerosol solvent
applications of CFC-113 and 1,1,1-trichloroethane.  However,  while  some  of
these alternatives are functional, they are considered to be"less than optimal
for a variety of reasons.  For example, in applications where a  strong solvent
is required, but the use of a flammable solvent would  pose  serious  safety
risks, substitutes may include only hydrofluorocarbons (HFCs), HCFCs and
chlorinated solvents.  While these .solvents would be functional, HCFCs
contribute to ozone-depletion, and chlorinated solvents are toxic and may pose
health risks to workers and users of a product.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      8-2

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               Table VIII-1.  SUMMARY OF SUBSTITUTE  SOLVENTS  FOR
                 1,1,1-TRICHLOROETHANE AND CFC-113 IN AEROSOLS
                          Major Product Applications      Performance Factors

1

, 1 , 1-Trichloroethane
CFC-113
A&I Pest HH
* * *
*
Flammability
None
None
Density
1.32
1.57
Substitute  Solvents:

  Petroleum Distillates

  Aromatic  Hydrocarbons

  Alcohols

  Ketones

  Water Systems

  Dimethyl  Ether

  Chlorinated  Solvents


  HCFCs
High
High
High
High
Low to None
High
None
0.75
0.87
0.80
0.81
1.00
0.66
1.31-
1.62
                             None
1-1.21
* Denotes that  the  substitute solvent can be used in the product application
 indicated.
A&I
Pest
HH
Automotive and Industrial Products.
Pesticides.
Household Products.
Source:  Based  on  ICF 1989a.
                    * 199* UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       8-3

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      8.3,1  Reformulation Using Petroleum Distillates

      One alternative for the replacement of CFC-113 and 1,1,1-trichloroethane
in aerosol products is reformulation using petroleum distillates.  Due  to  the
high flammability of the petroleum products, reformulation from CFC-113  and
1,1,1-trichloroethane to petroleum distillates can only be performed  in  select
applications and with proper explosion proof equipment.  Commercially
available products reformulated with petroleum distillates and other
hydrocarbon solvents exist for various automotive products such as tire
cleaners, lubricants, spray undercoatings, and in household products  such  as
water repellents/shoe waterproofers, glass frostings, and insecticides.
Extreme care must be exercised in both the manufacture and use of these
products to reduce the risk of explosion.

      8.3.2  Reformulation to Water-based Systems

      Reformulation from 1,1', 1-trichloroethane or CFC-113 to water-based
systems can be performed in a number of applications, including shoe  polishes,
foggers  (partial or total release insecticides used to control infested
rooms), mould release agents, and fabric protectants.  The major
disadvantage/concern of reformulation of 1,1,1-trichloroethane or CFC-113  to
water-based systems is the effectiveness of the final product.  These concerns
arise from several fundamental differences in the systems.  For example, it is
generally agreed that water-based foggers are less effective because  they  do
not disperse well and they result in large particle sizes (Ortho 1989,
McLaughlin Gormley King Company 1989, Sprayon 1989).  These factors make the
foggers less effective than foggers which utilize 1,1,1-trichloroethane  since
the water tends to be ineffective at penetrating the exoskeleton of insects.
Tests are currently underway to produce water-based solvent mixtures  which
will be able to overcome this problem.

      Other drawbacks associated with water-based aerosol products include
long drying time and inability to sufficiently wet 'the surface being  sprayed.
The relatively slow evaporation rate of water .as compared to that of  CFC-113
or 1,1,1-trichloroethane results in a slow drying time.  While the drying  time
can be accelerated with the application of heat, it is still likely to be
significantly longer than the drying times associated with CFC-113 and 1,1,1-
trichloroethane.  Also of concern in some applications is the reduced
wettability of a formulation that has been reformulated to use water  as  the
primary solvent.  The high surface tension of water often results in  less
efficient wetting of surfaces being sprayed.  This is an especially important
consideration in applications such as mould release agents (UNEP 1994b).

      Despite these drawbacks, water-based aerosol formulations are becoming
more common in a wide variety of industries, especially among those wanting to
avoid the use of flammable solvents, HCFCs, and chlorinated solvents.

      8.3.3  Reformulation Using Organic Solvents

      There are a number of alternative organic solvents that can be  used  to
replace CFC-113 or 1,1,1-trichloroethane in many aerosol applications.   These
alternative solvents include petroleum distillates, alcohols, ketones,  and
terpenes. . These solvents are capable of removing a wide variety of
contaminants, and all are currently used in commercially available aerosol
products.  This strong cleaning power, coupled with the ability to solubilize


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      8-4

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other active ingredients, makes these alternative solvents attractive
substitutes for CFC-113 and, 1, 1',1-trichloroethane.

      There are two primary drawbacks associated with the reformulation of
aerosol products using organic solvents -- flammability and environmental
impact.  All of the aforementioned organic solvents are flammable and must
therefore be used with extreme caution to reduce the risk of explosion and
fire.  While many users are able to safely implement flammable formulations
with only minor process and handling changes, others may not be able to
overcome the risks associated with the flammability qf the solvents.  For
example, flammable solvents are not a viable alternative for the in-situ
cleaning of energized equipment.  The major environmental concern associated
with these organic solvents is their impact on the formation of smog and other
ground-level pollution.  In the United States, virtually all of these-solvents
are classification as volatile organic compounds (VOCs) and their use is
severely restricted in some geographic areas.  Nonetheless, where flammable
solvents are acceptable, reformulation using organic solvents is an attractive
option.

      8.3.4  Reformulation Using Nonozone-Depleting Chlorinated Solvents

      Reformulating aerosol products to use nonozone-depleting chlorinated
solvents in place of'CFC-113 or 1,1,1-trichloroethane is an option in limited
applications.  The chlorinated solvents that might be used are
trichloroethylene,  perchloroethylene, and methylene chloride.  The primary
benefit associated with these alternatives is their nonflammability.  This
property makes them"one of the few viable alternatives for aerosol cleaners
used on energized equipment.

      Potential formulators and users of aerosols containing these solvents
must be aware of their associated human health risks.  All three of these.
alternatives are potentially carcinogenic to humans and have accordingly low
occupational exposure limits (UNEP 1994a).

      8.3.5  Reformulation Without a Solvent

      In some cases where CFC-113 or 1,1,1-trichloroethane is used only -as a
solvent or carrier, and not as an active ingredient, it may be possible to
reformulate the aerosol product to function without the use of a solvent.  In
these nonsolvent systems', the active ingredient of the product is dispersed
solely by the force of the propellant.  Such a formulation is currently being
marketed by several manufacturers of aerosol .mould release agents, who have
observed increased performance in some applications because there is no longer
any possibility of the solvent attacking plastics or metals with which it
comes into contact.  However, it is also possible to obtain inferior
performance, primarily because of the uneven dispersion of the active
ingredient which may occur in the absence of a solvent carrier (UNEP 1994b).

      8.3.6  Reformulation Using HCFCs

      Another-alternative for replacing CFC-113 and 1,1,1-trichloroethane in
limited aerosol applications is reformulation with HCFCs.  At the present
time, • HCFC-141b is the only commercially available alternative, although it is
expected that HCFC-225 will become available for aerosol applications in the
near future.  HCFC solvents have much the same properties as CFC-113 and


                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT* *
                                      8-5

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1,1,1-trichloroethane, making them ideal replacements from a  technical
standpoint.  However, HCFCs are ozone-depleting substances and will  therefore
add further to depletion of the ozone layer.  HCFC-141b has an ozone-depletion
potential  (ODP) comparable to that of 1,1,1-trichloroethane,  and  should
therefore not be used as a substitute for 1,1,1-trichloroethane.   It is
important to note that HCFCs are a transitional substitute at best because
they are scheduled for a complete phaseout under the Montreal Protocol by the
year 2030.  In addition, certain countries have restricted the use of HCFCs  in
some applications.  Given these considerations, HCFCs should  only be
considered in applications where a nonflammable formulation must  be  used, and
even then, when no other alternative is satisfactory.

      8.3.7  Alternative Delivery Systems

      CFC-113 and 1,1,1-trichloroethane use in aerosols can also  be  reduced  if
alternative means of delivering the product are developed.  Two examples of
these alternative methods .are: . (1) a manual  "wet-brush"  (recirculating
liquid) system, as a substitute for aerosol brake cleaners used in repair
shops, and (2) increased use of professional  dry cleaning, services as a
substitute for the use of aerosol spot removers.  Although more examples of
alternative non-aerosol methods can be found  for the other aerosol products
that currently use CFC-113 and 1,1,1-trichloroethane, the cost data  presented
in this chapter uses these two applications as examples.
8.4   COSTS OF ALTERNATIVES

      Table VIII-2 presents the costs for the two groups of control
technologies for reducing 1,1,1-trichloroethane use  in aerosol products:  (1)
the reformulation of aerosol products, and .(2) a switch to an alternative
method to deliver the product other than by means of an aerosol.  The
methodology used to estimate the costs associated-with the reformulation of
aerosol products currently using l.l.l-'trichlbroethane is based on a previous
analysis (ICF 1989b) and includes the/estimation of  reformulation costs per
plant (i.e., R&D, marketing, and capital costs), the number of aerosol plants
that would incur these costs (based/on the production volume of an average
"model" plant), and the calculation of total annualized cost.

      Using reformulation with petroleum distillates as an example, it is easy
to see the effects of such a change on the production cost of aerosol
products.  Looking first at the cost of the product  itself, the use of this
new solvent will most likely increase the cost of the container in which  it  is
distributed.  Due to the fact that the petroleum-based solvents have a density
of about 0.75, as compared to 1.32 for 1,1,1-trichloroethane, a larger
container will be needed in order to hold a similar  weight of the product.
This is a significant consideration since the cost of the packaging accounts
for almost 36 percent of the product cost to the manufacturer (ICF 1989).

      For the case of petroleum distillates, the change from 1,1,1-
trichloroethane use will necessitate expenditures in research and development,
labelling,  and public education.  Due to the flammable nature the new solvent,
a public education program might be needed to inform potential users of the
proper precautions which should be taken when using  the product.  In addition,
increased research and development will be needed to search for ways by which
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      8-6

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    TABLE VIII-2.  COSTS  OF  CONTROLS  FOR 1,1,1-TRICHLOROETHANE IN AEROSOLS
     Control Option
Alternate Delivery Systems

     Occupational Uses

     Consumer Uses
 Incremental Costs? (thousand dollars)
   1                           Total
             R&D and       Annualized
Capital     Marketing6       Costsc
Reformulation to:
Petroleum Distillate
Water-based Systems

5 , 594
92.3 . ~ 2,244

. 622.7
260.2
170,700d
19,000.0
a  Raw material costs are not considered in this analysis primarily because
the replacement chemicals in both,  the  reformulated products and the  alternate
delivery systems are as  expensive  as  1,1,1-trichloroethane '.

b  Includes R&D and marketing costs associated with  the  reformulation of
various automotive and industrial  products, household products,  and aerosol
pesticides currently using methyl  chloroform.

c  Costs are discounted at the social rate of discount  (2 percent) over  the
equipment lifetime (10 years).

d  These costs represent the capital  investment required if  all  users of
1,1,1-trichloroethane-based brake  cleaners purchased alternative equipment.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                    •8-7

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the reformulated solvent might be made safer and more efficient.  Finally,
retrofitting of assembly line equipment will most likely be needed in order to
provide adequate measures for fire-prevention as well as firefighting (ICF
1989a).

      The example just presented is perhaps the most extreme case.  Though the
cost impacts of other alternative solvents may not be as extensive as those
for petroletun distillates, they may be significant.

      The costs of the two options considered in the alternative delivery
system category include the costs incurred by the current users of aerosol
products (e.g., brake shop owners and consumers) and do not include costs to
the aerosol industry.  It is estimated that aerosol manufacturing facilities
could either reformulate these products or produce other, aerosol products
without incurring major financial losses.

      An example of an alternative to consumer use of 1,1,1-trichloroethane-
based spot-removing aerosols is the use of professional cleaning services.
Aerosol spot removers are designed to reduce consumers' dry-cleaning costs by
providing consumers an easy way'to remove spots from dry-cleanable garments.
Most of the industry for aerosol spot removers has reformulated products to
use HCFCs in place of 1,1,1-trichloroethane.  In the event that aerosol spot
removers were no longer available, consumers would be forced to resort to
additional dry cleaning services.  These costs are based on the increase in
the number of times that consumers will have dry-cleaners remove spots from
garments that the consumer could have treated him or herself with aerosol spot
removers (ICF 1989b).

      The data used in this analysis includes experimental data on the number
of spot treatments obtainable from a can of aerosol spot removers, the likely
interval between dry cleaning events, the size of the spot remover market, and
current dry cleaning fees.  Spot removers used 1.1 million kilograms of 1,1,1-.
trichloroethane in. 1987.   The results of this analysis  indicate that
additional dry cleaning costs to consumers are approximately $20 per kilogram
of 1,1,1-trichloroethane used.  These are upperbound costs, because a portion
of current users of aerosol spot removers might decide  to "live with the spot"
a little longer, taking the garment to a dry cleaning service only when it
became time for general cleaning of the garment.  In this case, additional dry
cleaning expense would be avoided.  Even in this case, however, costs would
probably be higher, compared to other 1,1,1-trichloroethane controls, since
consumers pay more to have a spot treated by a professional dry cleaning
service than they do if they use aerosol spot removers.

      Aerosol brake cleaners are used by brake mechanics to-(l) remove oil,
grease and brake fluid from the brake drum system, (2)  remove the excess .dust
accumulated inside the brake housings, and_(3) remove glaze from brake pad
surfaces.  To remove oil, grease, and brake.fluid, the best alternative to an
aerosol is to degrease manually, using a petroleum-naphtha-based solvent and
an ordinary scrub brush.   To remove excess dust and glaze,  there are several
alternatives, to cleaner application by aerosol, including vacuum enclosures,
recirculating liquid systems, and wet brush systems.  The liquid applied
generally contains water and a surfactant (PEI 1983).   The wet-brush is the
lowest-cost option.  It is estimated that there are 297,416 brake repair shops
that employ aerosol brake cleaners (PEI 1983).  The cost of substituting with
the wet-brush system is $574 per shop, so the investment for all shops would


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT * .
                                        88
                                       - O

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amount to  $170.7  million.  Operating costs  are  assumed to be approximately the
same as the  current costs of aerosol brake  cleaners;  thus, the cost of the
equipment  is believed to be indicative of the additional costs incurred.
Using 10-year  and 2 percent discount rates,  annual  costs amount to
approximately  $19 million.
                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       8-9

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                                   CHAPTER' 9

       OTHER SOLVENT USES OF OZONE DEPLETING SUBSTANCES (CFC-113, 1,1,1-
                   TRICHLOROETHANE AND CARBON TETRACHLORIDE)
9.1  BACKGROUND                                        '

      Some amount,  in most  cases  relatively  small  quantities,  of CFC-113,
1,1,1-trichloroethane,  and  carbon tetrachloride  are  employed in a number  of
industry and  laboratory applications.  These include:

            bearer  media for  coating  and  impregnation
            vapour  soldering  technology
            component drying
            riveting and machining                             ,  •
            airplane hydraulic  system testing
            fabric  protection and coating
            semiconductor manufacturing
            miscellaneous testing (including leak  detection)
            mould release agents
            film cleaning
            component cooling
            manufacture of  solid  .rocket motors
            oxygen  systems  cleaning
            correction  fluids
            fabric  spot remover
            process solvents

      The Committee consensus is  that by  1996, in  accordance with the Montreal
Protocol, most of the CFC-113,  1,1,1-trichloroethane,  and  carbon tetrachloride
used for these applications .could be  replaced by the alternatives discussed in
this chapter.

      In the  applications of  laboratory analyses and in  the  manufacture of  a
specific large scale solid  rocket motor,  the Parties have  granted an exemptio,n
for continued use of specified  ozone-depleting solvents  for  1996  and 1997.
The exemptions are  subject  to review  and  alternatives  are  being investigated.

      In the  case of use of ozone-depleting  substances as  process chemicals,
there are also a number of  alternatives identified in  this report.  In
addition, an,  in-depth review  of alternatives is  planned  for  completion and
presentation by the Technical and Economic Assessment  Panel  to the Parties  by
early 1995.              .               ^


9.2  BEARER MEDIA FOR COATING AND IMPREGNATION

      In some applications, CFC-113 is used  as a carrier of  lubricants that
reduce frictional damage.   In a typical process, gold-plated contacts .are


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT  *
                                       9-1

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dipped into a bath of CFC-113 containing two percent of a lubricant such as
perfluorinated polyether.  The CFC-113 acts both as a cleaner and a lubricant
bearer.  The following alternatives have been identified for this application
(Nordin 1988, Owens 1990):

      •     Use of mechanical methods, such as spraying or rolling, to
            dispense the lubricant.   (The problem of excessive application of
            the lubricant must be solved as the lubricant must not exceed four
            micrograms per contact.

      •     Application of the lubricant via emulsions.  (These should be
            water-based emulsions if  possible.)

      •     Use of an alternative non-halogenated solvent compatible with
            fluorinated lubricants.

      •     Use of an alternative lubricant.  (The lubricants should be
            compatible with the materials in use.)

      •     Use of a perfluorinated solvent has been demonstrated with
            perfluoropolyether lubricants and is in commercial use in several
            countries.  However, because of the high global warming potential
            of perfluorinated solvent's, they should only.be used in
           • applications where emissions.can be kept at or near zero.

      •     Hydrochlorofluorocarbons  (HCFCs) might be considered despite their
            small contributions to ozone-depletion.  It is important that
            HCFCs only be used where  other alternatives are considered
            unacceptable, and that recovery systems be used in conjunction
            with HCFCs!

      •     HFCs might be considered  despite their contributions to global-
            warming.  It is important that HFCs only be used where other
            alternatives are considered unacceptable, and that recovery
            systems be used in conjunction with HFCs.
                     i

9.3  VAPOUR SOLDERING TECHNOLOGY           ^

      Vapour-phase soldering, also known as condensation soldering, is a
reflow method that involves boiling a liquid and putting the cool electronic
assembly along with unmelted solder into the hot vapour.  The vapour raises
the temperature of the cool electronic assembly and the solder until the
solder melts.  Because of its all-around heat application, vapour-phase
soldering is one of a limited number  of soldering processes that, in
principle, enables both sides of a substrate to be soldered simultaneously!
It cannot, however, be used as the only soldering process in mixed assemblies
because the process can damage temperature-sensitive bodies on some leaded
components (Pawling 1987).

    .  The primary liquids used in vapour-phase soldering -- nonflammable
perfluorinated organic compounds -- are nonozone-depleting but costly.  In
addition, they have a'very high global warming potential.  To minimise, primary
vapour losses, a less expensive secondary, vapour blanket .using a chemical with
a lower boiling point, such as CFC-113 (boiling point 47.6°C), is often used.


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      9-2

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With standard top loading batch equipment, this cuts losses of the primary
vapour by a factor of ten (Seidinger 1989).  CFC-113 also serves as a conduit
for the release of toxic hydrofluoric acid and perfluoroisobutylene (PFIB)
that may be generated if the primary vapour overheats.  To minimise vapour
losses and reduce emissions of toxic compounds, the blanket should be operated
at a low temperature.  The interface of the two vapours forms a zone where the
secondary vapour can also break down, releasing hydrochloric and hydrofluoric
acids, phosgene, and carbonyl fluoride.  Treating the condensate will not only
eliminate most of these dangerous by-products but will also reduce corrosion
of the machine itself.

      Two possible alternatives to using CFC-113 to form a secondary vapour
blanket in reflow soldering include:

      •     Eliminating the use of a secondary vapour blanket.  Although joint
            quality would not suffer, eliminating the secondary blanket could
            increase production costs for the reflow soldering operation by a
            factor of 10.  A primary vapour recovery unit that claims to
            recover up to 80 percent of any primary vapour entering the
            extraction system is now available.  With this-unit, net fluid
            costs could be reduced from approximately U.S. $10-14/hour to U.S.
            $3-4/hour.

      •     Using a secondary vapour blanket that does not deplete the ozone
            layer.  Recently a perfluorocarbon liquid has been introduced as a
            possible substitute for the secondary blanket.  The compound has a
            half life of approximately 1,000 years and does not contain
            chlorine, bromine, or hydrogen atoms.  (Niemi 1991)  However, the
            extremely long atmospheric^lifetime of perfluorocarbons give them
            high global-warming potentials.  Therefore, they should only be
            used in equipment that is specially designed to minimise
            emissions.  To replace perfluorocarbons in this and other
            applications, an alternative known as hydroflubrocarbons (HFCs)
            are currently being developed.         •

      Where specifications and throughput allow, IR spidering is also an
alternative process.  Table IX-1 summarises a recent evaluation comparing the.
use of CFC-113 and,a perfluorocarbon as the secondary blanket in vapour-phase
soldering equipment.  The results of this test show:

      •     CFC-113 and the perfluorocarbon are consumed in similar
            quantities.

      •     The rate of corrosion is somewhat lower for the perfluorocarbon,
            as measured by the copper wire method.

      •     An equivalent amount of PFIB is generated for both
            chemicals.                               '

      •     The amount of total hydrohalic acids generated is much lower for
            the perfluorocarbon.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                      9-3

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      Table IX-1.  COMPARISON  OF  CFC-113 AND A SUBSTITUTE
         PERFLUOROCARBON AS A  SECONDARY VAPOUR BLANKET
       Characteristic             CFC-113         Perfluorocarbon
Rate of Consumption (m3/hr)     1.14-1.51 x 1CT4    1.14-1.51 x 10'4

Vapour Temperature  (°C)
      Secondary  vapour            55-60              58-61
      Primary vapour             216-218             217-218

Rate of Corrosion (mm/yr)         5.59 x 10'2          2.03 x 10'2

Perfluoroisobutylene Generation
      (Mgm/m3/hr)                 <0.227              <0..227

Hydrofluoric Acid Generation
      (/igm/m'/hr)
         150°C                      682  (8 HC1)       1140
         215°C                    9,090 (240 HC1)      4420
Source: Seidinger  1989
            *  1994 UHEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                               9-4

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 9.4  COMPONENT  DRYING

      Many precision devices,  such as  electrical  and electronic parts,
 mechanical assemblies,  optical equipment,  and delicate instruments,  come into
 contact with water  during  manufacturing and assembly.   Such parts  must  be
 dried promptly  after cleaning  to  prevent rusting,  water staining,  and general
 deterioration in  quality that  can lower product reliability.   A dedicated
 drying or dewatering process is often  used to remove moisture.   Typical
 techniques include:

      •     centrifugal  processing followed by hot air drying
      •     absorbent drying using alcohols,  such as ethanol,  isopropanol,  and
            acetone
      •     vapour  drying  with non-CFC solvents,  such as  chlorocarbon
      •     displacement or solubilisation drying using CFC-113-based drying
            formulations (Johnson 1991).

 The trade-offs  among these drying techniques  are  compared in Table IX-2.

      Process recovery and conservation methods for CFC-113  in drying are
 similar to those  in  typical solvent cleaning  systems.   The use  of  CFC-113, for
 drying represents, perhaps, less  than  10 percent  o.f the CFC-113 used for
 cleaning, but many of the  applications are critical (Johnson 1991).

      9.4.1  Semiconductors1
                                              \
  .  '  Integrated  circuits, the major product  of the semiconductor  industry,
 are a combination of electronic devices  including transistors,  diodes,
 resistors, and  capacitors  which are placed in a-single, semiconductor crystal.
 During the fabrication of  integrated circuits, CFC-113 is  used  for'
 displacement drying  of semiconductor materials, such as wafers.  Depending  on
 the integrated  circuit being made (e.g.,  metal oxide semiconductors  (MOS) or
bipolar), different  process steps,  which can  include wafer preparation,
 oxidation, doping, and layering,  are repeated so  that  drying  may occur  many
 times during the  fabrication process.

      9.4.2  Printed Circuit Boards     .               .

      Of the four processes commonly used for critical drying of printed
circuit boards  during manufacturing, two processes  use CFC-113.  These
processes involve:                .

      •     Dipping  the  wet boards  in  a .circulating bath  of pure CFC-113.   The
            water is displaced, floats on the solvent  surface,  and is pumped
            off the  surface into  a  separator  so that the boards  are  not re-
            wetted when  removed.   Following this  bath,  the board is  usually
            passed through a vapour degreaser containing  a CFC-113/ethanol
            azeotrope to remove residual water traces.       .
     1   Semiconductors are materials having an electrical conductivity between
that of a conductor and an insulator.  They are either discrete devices  such
as transistors or thyristors, or integrated circuits that contain  two  or more
devices in a single semiconductor crystal.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      9-5v.

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               Table IX-2.  COMPARISON OF DRYING TECHNIQUES
Dewatering
Technique
         Advantages
     Disadvantages
Centrifugal
processing and
hot air drying
Low equipment cost,
handling.
Can be used for simple
shape products.  High
energy costs, spots.
Absorbent
drying using
alcohols
Drying at room temperature.
Large solvent
consumption.  Needs
fire protection
measures.
Displacement
drying with
PFCs and HCFCs
Satisfactory drying at 50°C
or below.
High cost of solvents.
Bear in mind OOP and
GWP.
Displacement
drying with
chlorinated
solvents
Displacement
drying using
CFC-113
Proven, available, possible
to retrofit equipment
Energy efficient, rapid
drying.
Possible compatibility
with materials.
Requires careful
management and
handling.

Higher equipment costs.
Increasing operating
costs.  May leave a
residual film.
Depletes stratospheric
ozone layer.
Source:  Johnson 1991.
                  * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                    9-6

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      •     Dipping the wet boards  into  a  surfactant/CFC-113 mixture  to
            emulsify the water,  then using a vapour degreaser  to  remove  the
            surfactant.

The other two critical drying processes,  use alternative  solvents.   The
circuits can "be dried by:

      •     Dipping the wet boards  into  two successive isopropanol  tanks
            fitted with dryers

      •     Dipping the wet boards  into  a  water-displacement product  based on
            toluol.  The water drains  through a grid  in  the bottom  of the
            tank.

CFC-113 use could be eliminated  by  switching to these two  alternative drying
processes.

      Another method for eliminating CFC-113 in this  application  is to
eliminate the use of water in the manufacturing process, thereby  eliminating
the need for drying.  Alternatives  to  the  use of water-based processes are
discussed in detail in the chapter  on  Electronics Cleaning.  For  manufacturers
using small quantities or operating in developing countries, alcohols and
alcohol/perfluorocarbon mixtures are suitable alternatives to  CFC-113 and
1,1,1-trichloroethane, for unlike aqueous  and semi-aqueous processes, water
treatment systems are not required  (Matsui 1991).

      9.4.3  Mechanical Assemblies

      For further information, refer to  the chapter on Precision  Cleaning.

      9.4.4  Metal Surfaces

      For further information, refer to  the chapter on Precision  Cleaning.


9.5   RIVETING AND MACHINING

      CFC-113 is used as a 'lubricant and coolant in certain drilling  and
riveting operations during the manufacture of aircraft frames, particularly
wing assemblies.  In this operation, an  automatic drill/riveting  machine
clamps the aircraft skin and stringer  together, drills -and countersinks  a
close tolerance hole through the two pieces, inserts  and compresses a rivet,
and shaves the rivet flush to provide  an aerodynamically smooth surface.   The
entire operation takes approximately seven seconds.   CFC-113 is used  primarily
to carry away heat generated during the  drilling and  shaving processes,  which
extends the bit life of the dr.ill and  improves the finish  of the  hole.  .For
one company, CFC-113 also lubricates the rivet as it  is  inserted  and  prevents
corrosion in the riveted area after assembly.  For some  applications,
lubrication of the rivet is critical to  ensure that the  rivet  completely
expands into the drilled hole.   Incomplete "fill" leads  to fatigue  stress  and
the possibility of leakage from  fuel tanks located in the  wings of  the
aircraft.

      Manufacturers agree that non-evaporative lubricants  are  adequate for
holes less than two or three hole diameters in depth.  For deeper holes,


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT  *
                                      9-7       .'

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 lubricants combined with cold  air  is  considered more promising.   Possible
 substitutes  for CFG-113 in  shallow holes  include  long  chain fatty alcohols  and
 emulsified water/oil mixtures.  Manufacturers  agree that  the ideal substitute
 must:

       •      have appropriate coolant/lubricity characteristics
       •      be nontoxic and nonflammable  for worker safety
       •      leave no residue that  could prevent good bonding of  paints  and
             sealants
       •      be noncorrosive

       Additional research is needed to determine  whether  non-CFC alternatives
 will meet these requirements.   In  recent  years, the International Cooperative
 for Ozone Layer Protection  (ICOLP) has promoted intercompany research between
 McDonnell-Douglas, Boeing,  and British Aerospace  on alternative  methods of
 riveting (British Aerospace 1990;  Grumman Aircraft 1990).
9.6   AIRPLANE HYDRAULIC SYSTEM TESTING

      New airplane hydraulic systems are  routinely  tested  for  leaks by  adding
hydraulic fluid through existing airplane ground  service connections,
pressurizing a portion of  the  system, and then visually inspecting for  leaks.
Discovered leaks are stopped and spilled  hydraulic  fluid is  cleaned up.   This
process is repeated at higher  pressures for each  portion until the entire
hydraulic system is pressurized to  3000 psi (210  kg/cm2) without leaks.
CFG-113 is used to clean up the spilled hydraulic fluid.   This solvent  is
necessary because it can be used inside the airplane  fuselage  without
flammability or toxicity problems.  Also,  because CFC-113  is more dense than
hydraulic fluid and completely evaporates, it is  possible  to flush
inaccessible areas without concern  for corrosion.

      A new process that significantly reduces the  use of  CFC-113 has recently
been used for hydraulic systems testing.   The .process uses inert gas and audio
inspection.  Pressurized nitrogen is introduced into  the hydraulic system
through a hydraulic pump filter module.   As the gas enters the system,  it
bypasses component valves  that are  designed to operate under hydraulic  fluid
pressure.  Bypassing these valves allows  the entire system to  be filled at
once, including the fluid  reservoir which has a 75  psi  (5.3  km/cm2) relief
valve.  Although this relief valve  limits the maximum pressure that can be
applied to the system, it  is still  great  enough to  force gas through system
leaks that would require much  higher pressure if  hydraulic fluid were used.
By using an ultrasonic sound detector tuned to the  frequency of the escaping
gas, a 95% or better leak  detection rate  is achievable.  The new process is
very capable of finding major  leaks that  previously required large quantities
of CFC-113 for clean up after  testing with hydraulic  fluid.  The few leaks
that show up when the system is finally fully charged with hydraulic fluid  are
relatively small and require much smaller quantities of CFC-11'3 for clean up.
However, an alternative is still being sought for this reduced, but necessary
solvent use.

      The new gas leak detection system has reduced CFC-113  consumption for
hydraulic spill .clean up,  on average from 25 to 3 gallons  (95  to 11 litres)
per plane (Boeing 1991).
                    * 1994 UHEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                      9-8

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9.7   FABRIC PROTECTION AND  COATING

      1,1,1-Trichloroethane  is used  as  a  solvent  in fabric  protection agents
sold for both industrial  and consumer use.   Like  other  chlorinated solvents,
1,1,1-trichloroethane  "dissolves"  the polymeric fluorinated compounds that
protect the fabric  (teflon,  for  example),  causing them  to swell  so that  a more
homogeneous mixture or dispersion  can be  applied.

      There are  three  general classifications  of  fabric protection products
which use 1,1,1-trichloroethane.   The most common is  the aerosol can  which is
widely used by consumers  to  treat  fabrics, in their home.  The  second  is  for
Retailer Applied Fabric Treatment  (RAFT),  where a retailer  provides the
application of a fabric treatment, usually for soil or  stain protection,  as an
after sale service.  The  third application method is  mill application.   Mill
application has  a long history and is either done at  the mill, where  the
fabric is manufactured, or by a  special contractor who  performs  the
application either  for the manufacturer or for a  user of the fabric (Mertens
1991a).                                                   ,

      The aerosol application is perhaps  the largest  and most  diversified
segment as there are many formulators and packagers of  aerosol fabric
protection products.  They are usually  based on a fluorocarbon or a silicone
resin and use a  solvent carrier.   The solvent  most commonly used is 1,1,1-
trichloroethane, primarily due to  its excellent solvency, fast evaporation
rate, low flammability, low  toxicity, and nonphotochemical  reactivity (Mertens
1991a).        .       •

      The Retailer Applied Fabric  Treatment is usually  found in  the retail
furniture business and in automotive dealerships.   The  seller  of a piece of
upholstered furniture or  a fabric  automobile interior often offers the
application of soil and stain preventative spray  after  the  sale  of the product
itself.  This application uses predominately fluorocarbon resin  with  some
silicone.  The fluorocarbon  resins are  often formulated with 1,1,1-
trichloroethane.  There is a wide  variation in the quality  of  the application
methods in this'  area.  Some  of the retailers have large warehouse operations
where they can install ventilation booths and  have well trained  operators
performing the application.   Others  are small  operations and may spray on the
fabric protection at the  loading dock door.  Because  of these  varied
application procedures, the  properties  of 1,1,1-trichl'oroethane  are well
suited to this application (Mertens  1991a).

      There is also an-extension of  the RAFT application where fabric
protectants are  applied in the home.  In  this  application,  a service  company
comes to the consumer's home and applies  fabric protection  to  furniture,
drapes, and/or carpeting.  The toxicity,  flammability,  and  odour are  major
factors in the choice of  solvents  used  in these applications.  The consumer  '
does not want any lingering  odours in the home after  the application,  of  the
fabric protector, and  the applicator needs to  be  concerned  about the
flammability and toxicity of the product  during the. application  (Mertens
1991a).  •

      Mill application of fabric protectors is usually  performed on an      :
automatic processing machine custom  designed for  the  operation.   The
advantages of mill application are the  ability to cover the cloth completely
with the fabric  protector and to automate the  process.  These  systems usually


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      9-9

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incorporate some form of vapour recovery, and because of this, 1,1,1-
trichloroethane has not been the solvent of choice for the larger mill
treatment operations.   Trichloroethylene has often been used where vapour
recovery is incorporated into the process (Mertens 1991a).

      Replacement of !,!•, 1-trichloroethane in fabric protection applications
will vary significantly in each of these applications.  For example,  3M has
developed a hydrocarbon solvent version of its Scotchguard™ fabric protection
products.  This product is flammable and contains volatile organic compounds
(VOCs), and therefore may contribute to the formation of tropospheric ozone
(smog).  In many areas there are stringent regulations controlling the use of
VOCs in aerosol cans,  and the use of these alternatives may be restricted in
those areas that have high tropospheric ozone levels.  In addition,  there will
be a need for consumer education to illustrate the risks associated  with the
flammability of such replacement products (Mertens 1991a).

      Replacement in RAFT applications will be difficult for those areas that
have tropospheric ozone problems.  The most likely replacement solvent for
this application will be mineral spirits or hydrocarbon solvents.  With both
types of solvents, the dry time will be extended and the flammability may be
of concern to users.  Additional capital expense may be required to  handle and
use these solvents safely (Mertens 1991a).

      DuPont has just introduced a water-based fluorocarbon resin system which
will- replace solvent-based fluorocarbon products that are currently  used in
this application.  The system will require the purchase of special equipment
for the application of. the water-based product.

      Mill applications appear to have the greatest opportunity to change to
alternative systems as they can substitute solvents and use add-on controls to
minimize emissions of solvents that are VOCs, Hazardous Air"Pollutants, toxic,
or otherwise pose a threat.  Trichloroethylene with carbon adsorption has been
successfully used in this application for many years, and can easily be
extended to replace any use of 1,1,1-trichloroethane (Mertens 1991a).

      Although it is possible to obtain solutions or dispersions of  polymeric
fluorinated compounds using other solvents such as hydrocarbons and  esters,
there is still some loss of the solvent effect.  In addition to its  "swelling"
capacity, 1,1,1-trichloroethane also possesses an unusually high density
(nearly twice that of other solvents) --a characteristic which reduces the
tendency of the solids to settle.  Alternative formulations will require more
frequent and thorough agitation to keep the solids suspended.
9.8   SEMICONDUCTOR MANUFACTURING

      9.8.1  Plasma Etch Processing
                          •x
      As shown in Table IX-3  (Mocella 1991), several CFC and  fluorocarbon
compounds are used in plasma  etching of silicon wafers.  Of these materials,
FC-14 (CF^),  CHF3 and  C2F6 do not contain chlorine or bromine  and are not
ozone -depleters,  but some (e.g. C2F6)  have high'global-warming potentials.
The remaining materials deplete ozone and will be phased out  by the year  1996
in developed countries under  the Montreal Protocol. ' Several  alternatives are
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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now available while others require further testing and development  (Felty
1991).

      Mixtures of various fluorocarbons  (PCs) and hydrofluorocarbons  (MFCs)
with nonozone-depleting chlorine sources may be an alternative used in the
etching process  (see Table IX-4).  Some of these (e.g., SF6, CF4,  C2F6, HFCs)
may have high global-warming potentials.  Many of these alternatives  are in
the development  stages and transition to high volume production with  data on
cost and impact  on production yields have not yet been determined.  Adopting
any of the other alternatives will require modifying processes to account for
variances in reaction kinetics and materials and insuring equipment
compatibility.  Another factor limiting the attractiveness  of these
alternatives (Felty 1991) is conversion costs or loss in yields.

      One possible option is the use of chlorofluorocarbon  (CFC) alternative
compounds.  Several of the fluorocarbon compounds listed in Table IX-5 are
potential replacements for existing CFCs.  Many of these compounds  have been
evaluated as etchants, with some reported success (Mocella  1991).   Like the
substitutes, some of the materials have no ozone-depleting  potential  while
others, primarily the HCFCs, have low ozone-depletion potentials and  may, for
a limited time,  find uses in critical applications.  However, potential users
of HCFCs should  be aware that these chemicals were recently added to  the list
of substances controlled under the Montreal Protocol and are currently
scheduled to be  completely phased out by the year 2030, with a 99.5%  reduction
required by the year 2020.

            9.8.2  Oxide Growth Processing

      1,1,1-Trichloroethane is used for silicone oxidation  in diffusion
furnaces during  semiconductor wafer fabrication processing.  1,1,1-
Trichloroethane  is delivered through a leak tested system to the silicon
oxidation furnaces where the following reaction takes place:

            CH3CC13  +  2  02 -- 2 C02 + 3 HC1
            4 HC1 + 02 -- 2 C12 + 2  H20

It should be noted, however, that none of the 1,1,1-trichloroethane is emitted
to the atmosphere.  This use is a transformation process and should be treated
in the same way  as feedstock applications.  The combustion  reaction is
quantitative, whenever sufficient oxygen is present.  Even  in an oxygen
deficient environment, 1,1,1-trichloroethane quantitatively decomposes at the
furnace temperature forming carbon, carbon monoxide and HC1.  The chlorine
species produced as by-products of the diffusion reactions,•chlorine  and
hydrogen chloride gases, are scrubbed to prevent emission to the troposphere.

      9.8.3  Semiconductor Degreasing           .

      CFC-113 and 1,1,1-trichloroethane are used in the electronics industry
to degrease semiconductors as part of the silicon wafer fabrication process.
In.the late 1980s, two companies jointly announced the introduction of a new
technology for cleaning semiconductor wafers.  The technology, called "water-
ice cleaning," does not require CFC-113 or 1,1,1-trichloroethane.   It relies
instead on a spray of ice particles 30 to 300 microns in diameter.  The
particles, are delivered at close to the speed of sound and,at temperatures
below -50°C.  The hardness and size of the particles as well as the pressure


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     Oil'

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                  Table IX-3.  HALOCARBON PLASMA ETCHANTS
Designation
CFG -11
CFC-12
CFG -13
CFC-13Br
FC-14
HFC-23
CFC-li5
FC-116
Carbon Tetrachloride
Formula
CFC13
CF2C12
CF3C1
CF3Br
CF4
CHF3
C2F5C1
C2F6
CC14
OOP
1.0
1.0
1.0
10.0
0.0
0.0
0.6
0.0
1.1
      Source:   Adapted from Mocella  1991.
     Table IX-4.  POSSIBLE MIXTURES FOR CFG REPLACEMENT IN PRY ETCHING
Alternative 1 : Fluorocarbon +
CF4
C2F6
CHF.3
Alternative 2 : . Fluorine Source +
• NF3
SF6
SiF4
Chlorine Source
C12
HC1
SiCl4
BC13
Chlorocarbon
CCl4a
CHC13
8  CC14 is an ozone-depleting substance  (ODS)  and scheduled for  a  phaseoUt
under the Montreal Protocol.

Source:  Mocella 1991
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             Table  IX-5.  CFC  ALTERNATIVE ETCHING COMPOUNDS
Designation
HCFC-22
HCFC-123
HCFC-124
HFC-125
HFC-134a
HCFC-141b
HCFC-142b
HFC-152a
Formula
CHF2C1
. CF3CHC12
CF3CHFC1
C2HF5
CF3CH2F
CFC12CH31 . 5
CF2C1CH3
CH3CHF2
- , ODP
0.055
0.02-0,
0.02-0.
0.0
0.0
0.11
0.065
0.0


.06
.04





Source:   Adapted  from Lerner,  Mocella 1991.
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 and angle of the spray can be controlled as needed.   This process is designed
 for use in place of the vapour degreasing stage of wafer processing (Nikkei
 Sangyo Shinbun 1989,  Denpa Shinbun 1989).

       9.8.4  Photolithographic Processing

       The photolithographic process for semiconductor wafer fabrication uses
 CFCs in various cleaning and drying processes.   In semiconductor
 manufacturing, processes and equipment are designed around various solvents
 and specific application needs (e.g.,  chlorine  source for etching silicone as
 part of the photoresist process).   The use of lasers and dry photoresist
 methods or the implementation of aqueous chemistry photoresists can reduce
 solvent dependency (Karash 1991).
 9.9   MISCELLANEOUS TESTING                                               /

     •  9.9.1 Leak Testing

       Both helium and CFC-113 are being used as an alternative to detect leaks
 in aircraft fuel tanks.   Any solvent compatible with tank materials can be
 used as a substitute for CFC-113.  Helium is being used successfully for leak
 detection.  In detecting leaks in metal gyro housings,  for example; CFC-113 is
 also used as a medium.  The integrity of the seal in certain metal gyro
 housings containing an inert gas atmosphere is tested during repair operations
 by immersing the housing which contains pressurized gas into a bath of CFC-
 113.  This method quickly locates any "gross" leaks that may exist.  Possible
 alternatives for gyros include replacing the CFC-113 with a blend of cyclic
 fluorocarbon ether and aliphatic fluorocarbon or with a solution made from
 pure water and a surfactant.  There are also systems available which detect  ,
 leaks of this type using infrared techniques (Hunt 1991).   Perfluorocarbons
 (PFCs) have associated global warming issues.
                                                           \                 .
       9.9.2 Laboratory Testing                      •

       CFC-113, 1,1,1-trichloroethane,  and carbon tetrachloride are also used
 for analyses in laboratories or investigations (e.g., quality testing and
 analyzing oils and greases).  Use of ozone-depleting solvents in laboratory
 applications has been granted a global exemption to the phaseout by the
 Parties to the Protocol for a period of two years beginning in 1996.   Refer to
 the global exemption and ongoing activity in this area for more information.
 9.10  MOULD RELEASE AGENTS

       In order to prevent adhesion, release agents form a barrier between a
 moulding compound and the mould.  Sometimes release agents also function as a
 lubricant and are used in the moulding of graphite epoxy thermoplastic,
 thermosetting plastic, and rubber parts.

       The active component in a release agent may be.mixed with the moulding
 compound (an internal release agent) or sprayed onto the mould prior to
 moulding (an external release agent).  Only,external release agents contain
.solvents.  Waxes, fatty acids, silicone oils, or fluoropolymers are normally
 used as the active component in external release agents.  To insure an even


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application of the release agent, the active component is diluted with solvent
to produce a formulation of one to five percent active ingredient and the
remainder a mixture of solvents.

       Commonly used in the solvent mixture to control both the flashpoint of
the release agent and the evaporation rate of the main solvent, 1,1,1-
trichloroethane's high density prevents sedimentation of the active
ingredients.  It is rarely used for its solvent capabilities.  Other
components of solvent mixtures include xylene, mineral spirits, methyl ethyl
ketone, .and ethanol.  With fluorinated polymer release agents, 1,1,1-
trichloroethane swells the fluoropolymer and makes it "fluffy," which
counteracts sedimentation and improves the agent's release properties.  In
release agents with other active ingredients, 1,1,1-trichloroethane does not
serve the same function and reformulation should prove simpler.

      The recent trend in industry is toward the use of internal release
agents or water-based external release agents.  Internal release agents,
however, are not good for foamed products since the structure of the foam is
partially controlled by surface-active foam stabilizers whose function is
disturbed by the internal release agent.  The plastic foam- industry,
therefore, is pushing the development of water-based external release agents.
The general'objection to water-based release agents is that they evaporate too
slowly and reduce the temperature of the .mould (which then lowers the
production rate).  Internal release agents are a possible alternative for
moulded rubber products.

      Several manufacturers of aerosol mould release agents have developed
"nonsolvent" formulations in which the active ingredient is dispensed without
the aid of a solvent.  This type of formulation has proven effective in some
applications.  A potential problem with nonsolvent mould releases is the
uneven dispersion and wetting that can occur because the active ingredient is
not- solubilized.
9.11  FILM CLEANING

      Prior to the introduction of the Lipsner Smith Motion Picture Film
Cleaning Machine, film was most often hand-cleaned.  A typical cleaning  .
operation would include a solvent-wetted wiping cloth and a set of rewinds.
The solvent of choice was carbon tetrachloride (Mertens 1991a, Tisch 1991).

      When Lipsner Smith designed the first automatic film cleaning machine,
carbon tetrachloride's excellent solvent action, its rapid rate of
evaporation, non-flammability, and its lack of any softening action on the
film were recognized.  Because of known toxic effects, Lipsner Smith
investigated alternative solvents and liquids that would provide the same
characteristics without the toxicity problem.  Some of the solvents evaluated
included cyclohexane, hexane, methylene chloride, perchloroethylene, 1,1,2-
trichloroethylene, 1,1,2-trichloro-1,2,2-trifluoroethane, and 1,1,1-
trichloroethane (Mertens 1991a, Tisch 1991).

      1,1,1-Trichloroethane, because of its desirable solvent characteristics,
its low cost and low toxicity, was chosen to be used with the mechanized
Lipsner Smith system.  From that point on, 1,1,1-trichloroethane has been  the
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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world's most commonly used film cleaning solvent and  is used  exclusively with
Lipsner Smith machines  (Mertens 1991a, Tisch  1991).

      With the exception of limited competition in France  and Japan,  Lipsner
Smith machines dominate the world's market  for film cleaning.  There  are
approximately 600 users worldwide who use approximately 1,500 units.   These
users make up an estimated 90 percent of the  total units used in  the  world for
film cleaning.  The typical L_psner Smith user is a film laboratory or film-
to-videotape transfer facility which operates two units with  an annual solvent
usage of about 15 drums (55 U.S. gallons/drum) (Mertens 1991a, Tisch  1991).

      The film cleaning industry is now rather steady as the  film-to-videotape
revolution of the 1970s and 1980s appears to have run its  course.  As a
result, the need for film cleaning will continue for  the next several years as
its only foreseeable replacement technology is coming from high-definition
video as an origination medium and/or as a  theatrical distribution medium.
However, this technology is unlikely to have any significant  impact for at
least ten years (Mertens 1991a, Tisch 1991).

      Since the addition of 1,1,1-trichloroethane to  the Montreal  Protocol,
Lipsner Smith has reviewed their needs and  the choice of 1,1,1-trichloroethane
as the cleaning solvent.  They have tested  several alternative cleaning
solvents with varying levels of success.

      Perchloroethylene is a viable substitute for 1,1,1-trichloroethane in
virtually all film cleaning applications.   As a result specially designed
cleaning equipment has been developed that  limits emissions of
perchloroethylene during the cleaning process.  This  special  equipment helps
to reduce the risks to workers associated with the toxicity of this
substitute.  Besides the health risks associated with the  use of
perchloroethylene, users must consider the  slower drying time as compared  to
1,1', 1-trichloroethane.  However, while perchloroethylene's lower volatility
increases drying time, it decreases solvent consumption because less  solvent
is lost through evaporation.   .                     .       .

      Another alternative that has proven effective in select applications is
water-based film cleaning.  These systems clean film  using a  spray system  and
a water/surfactant cleaner formulation.  The major concerns with water-based
spray cleaning are the potential for damage to the film caused by  the spray
and the need for a special drying stage in  the process.

      Two other alternative solvents are currently being evaluated for use in
the film cleaning industry -- perfluorocarbons (PFCs) and  hydrofluorocarbons
(HFCs).  Lipsner-Smith has been testing HFC 43-10 and hopes that  it can be
marketed in the film cleaning sector as a replacement for  1,1,1-
trichloroethane in the next one to'two years.  PFCs and HFCs  have  global-
warming issues which should be taken into consideration during evaluation.
9.12  COMPONENT COOLING                .

      CFC-11 and CFC-12 in aerosol cans are used  to cool, or  thermally  shock,
electrical components during certain diagnostic procedures  in the  fault
isolation of defective circuits and circuit components on printed  circuit
boards.  HCFC-22 is an alternative with a much lower  ozone-depletion potential


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 (ODP)  which provides essentially the same degree of cooling.  Howeyer, because
 HCFC-22 still contributes to ozone-depletion,  other alternatives have recently
 been developed.   These include HFC-134a or liquid, nitrogen in aerosol cans, as
 well as mechanical cooling devices using a vortex principle and compressed air
 (Hunt  1991).                                     •

       There are  other uses of CFC-113 and 1,1,1-trichloroethane such as pre-
 surgical skin cleaning and as a cooling media  in controlled fusion experiments
 (Stemniski, 1991a).   The Committee believes that the quantity used in such
 uses is small.   These uses were not discussed  in detail by the Committee.


 9.13  MANUFACTURE OF SOLID ROCKET MOTORS'

       Ozone Depleting Substances (ODSs) have, been routinely used globally  for
 decades in the manufacture of space launch vehicle solid rocket motors (SRMs).
 The  primary ODS  solvents used are 1,1,1-trichloroethane (TCA or methyl
 chloroform) and  CFC-113..  These substances are  used because^ of their excellent
 cleaning properties,' low toxicity,  chemical stability and non-flammability.
 Non-flammability is  of critical importance to  the safety of operations
 involving highly energetic propellant materials.

       In the  United  States,  large solid rocket  motors (SRMs)  are used to
 launch into space .communication,  navigational  and scientific satellites and
 the  manned Space Shuttle orbiters.   Large SRMs  include the existing Titan  IV
 SRM  as well as its upgraded version called the  SRMU and the Space Shuttli
 redesigned solid rocket motor (RSRM).                                   ^

       a.   The SRM manufacturing industry is unique in that there is no method
 to test the performance of an individual SRM prior to use.   The only way an
 SRM  can be tested is for it to be static fired.  In this way,  it is consumed
 and  cannot be used again (although various components may be re-used,  as is
 done in the Shuttle  program.)  Accordingly, SRM success can only be assured
 through rigorous manufacturing including detailed material specifications  and
 continuous quality control.

       b.   SRM manufacturing is also unique in  that the physics and chemistry
 of SRM functioning is currently only partially  understood.   For example,
 burning of SRM propellant has not been completely physically modeled or
.described due to the extremely hi-gh temperatures and gas velocities involved.
 Therefore,  the knowledge .of rocket manufacturing gained in the past is
 critically important to safety and reliability.  SRM manufacturers can change
 current methods  of manufacturing only after long-term testing and extensive
 evaluation.   Even after such evaluations,  it is not certain that the change in
 methodology will be  successful on the SRM.  Accordingly, the end users
 (customers)  of SRMs  require SRM manufacturers  to follow a rigorous system  of
 change control whose objective is to ensure that no changes in the SRM
'manufacturing process be made without explicit  advance approval based upon the
 results of the extensive testing.  Such testing and evaluation can involve
 numerous  steps up to and including full scale  ground-level static firing of an
 SRM.
                                                                 .  -•
       c.   Despite these technical safety and reliability challenges, the SRM
 industry has  successfully tested, approved, arid implemented significant ODS
 elimination.  Since  1989,  the four US manufacturers of large SRMs. have


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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eliminated over 1.6 million pounds of ODS use per year.  Current  (1994) ODS
usage is less than 48 percent of the use in 1989.  Usage in 1995  is estimated
to be less than 22 percent of 1989, and manufacturers have committed to
complete elimination of ODSs within the next few years.

Update on the NASA/Thiokol Applications

      The National Aeronautics and Space Administration (NASA) and Thiokol was
granted an essential use production exemption for 1996 and 1997.  NASA/Thiokol
have proceeded with their phaseout and are ahead of schedule for  eliminating
non-essential uses and investigating additional alternatives and  substitutes.
However, at this time NASA/Thiokol has not identified any acceptable
substitutes that would reduce their essential use below the previously
calculated amounts.  It is expected that they will request the government of
the United States to nominate an extension of essential use for the years
1998, 1999, 2000, and 2001.

Other U.S. Rocket Applications

      The Solvents, Coatings, and Adhesives Technical Options Committee (TOC)
reported in the March 1994 Report that it was likely that all manufacturers of
solid rocket motors use ODSs.  The Committee has confirmed that other U.S. and
European solid rocket motors use these substances and that these  organizations
are expected to nominate additional essential uses by January 1,  1995 for
decision in 1995.

      a.  The U.S. Air Force Titan Program may prepare an Essential Use
Exemption request for Continued Use of TCA for Critical Titan SRMU
Manufacture.  A nomination by January 1, 1995 could be considered for Decision
by the Parties in November 1995.

      b.  The Titan launch system offers assured access to space  for payloads
requiring heavy-lift capabilities.  Titan payloads have historically been
among the most important .and valuable in space exploration, e.g., the Gemini
manned space program, Helios solar observers, Viking Mars landers, and Voyager
deep space probes.  In the near future, Titan will launch Cassini, a fully
integrated international exploration spacecraft.  Communications,
environmental, scientific, and international security satellites  are expected
to be among the payloads carried into space on Titan in the next  decade.

      c.  The U.S. Titan program is working to completely eliminate the use of
ODSs and has invested substantial resources in successfully developing
alternatives to ODS use.  The original production schedule of the Titan solid
rocket motor upgrade (SRMU) required completion of hardware delivery in 1995.
At the same time that the amendments to the Montreal Protocol accelerated ODS
phase-out requirements, the Titan Program slowed down production  to complete
hardware delivery in 1999.  The combined effect of these two events has made
it impossible for the Titan Program to qualify alternatives for all ODS uses
by the ODS projection ban of 1 January 1996.  It is therefore necessary that
small-quantity critical uses of 1,1,1-trichloroethane continue, to allow
completion of the currently authorized compliment of Titan SRMUs.  These uses
cannot be modified without full qualification testing, which would disrupt the
launch schedule for years, cost hundreds of millions of dollars,  and
effectively halt the contributions of the Titan program to global access to
space.


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      d.  The Titan manufacturing team has undertaken an  intensive program  to
identify and evaluate alternatives  to ODS throughout the  rocket motor
production process.  The program includes eliminating non-critical uses  and
minimizing the quantities of ODS in essential uses.  The  prime contractor and
the major manufacturers of Titan IV vehicle components will  reduce all ODS  use
by 99 percent, from 1.33 million kg in 1989 to 9,200 kg in 1996.  Four small-
quantity ODS uses are critical to the success of  the Titan SRMU.  These  are
(1) surface preparation to ensure effective bonding of the internal  insulator
to the composite case, (2) surface  preparation to ensure  effective attachment
of breather cloth to the insulator  to permit uniform curing,  (3)  surface
preparation to ensure effective bonding of the propellant to  the  insulator,
and (4) dispersing propellant cure  catalyst during propellant mixing.  The
quantity of ODS necessary to complete SRMU manufacture for the final nine
flight sets is 3,660 kg per year or less for 1996 through to  .1999.

      e.  As in the case of the Shuttle Program,  substitutes  for  certain
critical uses with severe safety and reliability  concerns have not yet been
identified or have not yet been qualified.  Given this critical need for
safety and reliability, the Request for Exemption for continued TCA production
to support these essential needs may be submitted.  The request,  if submitted,
will need to contain detailed discussions of the  critical needs for continued
use, search for alternatives, and future plans to minimize the TCA quantities
needed.                               . '        '

European Rocket Applications

      The TOC has learned that ODS  are currently used in  European liquid and
solid rocket motors.

      a.  .Both CFC-113 and TCA are  used in the European Ariane Espace Program.
Efforts to find substitutes for these programs concern CRYOSPACE  for liquid
rocket engines and Societe Europeenne de Propulsion (S.E.P.)  for  solid motors.

      b.  CRYOSPACE will not apply  for an essential'use exemption this year.
Stockpiling and substitution are expected to address their present concerns.
S.E.P. is expected to apply for an  exemption before 1 January 1995.  The
processes involved might be slightly different from those of  the  Shuttle or
Titan IV Programs but are also similar because the Ariane rockets carry
comparable large payloads.  However, given the similar need  for safety and
reliability it is likely that their exemption will also contain detailed
discussions of the critical needs,  search for alternatives,  and future plans
to minimize the OD.S quantities needed.

Japanese Rocket Applications

      The TOC has learned that ODSS are currently used in Japanese solid
rocket motprs but an essential use  exemption is not expected.

      a.  Development of Japanese SRM technologies began  in  1953.  Over  40
years of research as well as trial  and'error resulted in  the  development and
manufacture of vehicles ranging from sounding rockets and satellite  launch
vehicles to defense related systems.  The Japanese space  rocket industry
Currently uses CFC-1-13 and TCA but  expects to phase out the  uses  by  the  end of
1995.  Latest achievements include  the solid rocket booster  (SRB).for the H-II
launch -vehicle, which is capable of  launching a 2  Ton satellite to


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Geosynchronous orbit.  The SRB is 1.8 meter in diameter, 23 meters long and
weighs 70 Tons.  Two SRfis are attached to the first stage of  the  two  stage H-
II vehicle which is 50 meters long and weighs 260 tons.

      b.  The three stage MV rocket with a 2.5 meter diameter SRM is  on
schedule in design and construction.  The Japanese scientists independently
developed specialized materials and manufacturing processes utilizing both
metallic and nonmetallic materials.  These materials require  surface
activation of each layer by an advanced shot blasting  technique rather that
the use of JCA.  Phase out of TCA is on schedule for the end  of 1995.

      c.  It is recognized that the Space Shuttle and  the Titan IV are
significantly larger vehicles relying on previously qualified technologies.
Due to their size, design and operational differences  and unique  performance
requirements, the Shuttle and Titan programs have critical uses not required
on Japanese launch vehicles.  Japanese industry has recommended that  Space
Shuttle and Titan programs continue to use TCA for critical uses  until the
schedule allows complete testing of alternatives.
9.14  OXYGEN SYSTEMS CLEANING

      In January 199,4 NATO identified the cleaning of oxygen systems as one of
the most difficult challenges facing military and aerospace applications.  In
Fall 1994, the International Cooperative for Ozone Layer Protection  (ICOLP),
Aerospace Industry Association  (AIA), U.S. Environmental Protection Agency,
National Aeronautical and Space Administration  (NASA) and the U.S. Air Force
convened a special workshop on  cleaning of oxygen systems without ozone -
depleting solvents.  This section of this report is based on their conclusions
and recommendations.                                          .

      Oxygen systems include:-   life support systems such as diving, totally
encapsulated suits, emergency breathing devices, fire & rescue backpacks,
submarine, aircraft, manned spacecraft, and medical applications; propulsion
systems such as liquid rocket motors; industrial systems such as chemical
production; and other unique,systems and customer products such as welding
equipment.

      Oxygen itself is chemically stable, is not shock-sensitive, will not
decompose, and is not.flammable.  However, use  of oxygen involves a degree of
risk because oxygen is a strong oxidizer that vigorously supports combustion.
Oxygen is reactive at ambient conditions and its reactivity increases with
pressure, temperature,  and concentration.  Most materials, both metals and
nonmetals, are flammable in high-pressure oxygen..  Therefore, systems must be
designed to reduce or eliminate ignition hazards.

      The successful design, development, and operation of oxygen systems
requires special knowledge and understanding of material properties, design
practices, ignition mechanisms, test data, and manufacturing and operational
techniques.  Oxygen systems must be kept clean because .organic compound
contamination, such as hydrocarbon oil, can ignite easily and provide a
kindling chain to ignite surrounding materials.  Contamination can also
consist of particles that could ignite or .cause ignition when impacting other
parts of the system.  Risk is increased by the.  typical proximity of oxygen
systems to very large quantities of fuel materials, and the common necessity


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     9-20

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of locating oxygen  systems  in confined spaces with  difficult  or  impossible
access and egress (e.g.  space ships,  submarines,  aircraft,  and surface  ships).
Despite safety engineering  efforts,  formal  safety requirements and procedures,
and cleaning with CFC  solvents--CFCs  are not the  only  solvents used--;  serious
accidents have occurred.  These  accidents have  resulted  from  a variety  of
situations including human  error, poor design and material  selection,
hydrocarbon and particulate. contamination,  and  unanticipated  circumstances
including collisions and acts,of war.

      The oxygen system  cleaning challenge  is' directly affected  by the
system's materials, system  geometry,  location and access, operational
parameters, and the type and extent of contamination including cleaning and
verification fluid  residue.   For example, the increased  atmospheric pressure
in deep diving drastically  lowers acceptable human  exposure limits for  solvent
residue.                                        '

      Examples of the  challenges presented  by these applications include  the
cleaning of the space  shuttle -external fuel tank, cleaning  of aircraft  carrier
liquid oxygen plants,,  cleaning of installed submarine  and transport aircraft
high pressure oxygen systems,  and the  gauges and  instrumentation associated
with each.  Examples of  devices  typically cleaned in these  systems include
tubing, gauges, regulators,  valves, and metering  devices.   It is usually  most
effective to clean  oxygen equipment at the  piece  part  level in a proper
facility.  It is more  difficult  to cleari oxygen equipment in  aircraft and ship
equipment in place with  difficult accessibility and temperature  extremes.
Additional challenges  occur in many other industrial oxygen systems such  as
those used in production and transfer  of both gaseous  and liquid oxygen,  in
medical applications,  and in welding.   Cleaning of  equipment  used in the
oxygen production industry  involves unique  challenges  such as  compatibility
with aluminum heat  exchangers.

      For oxygen systems are expressed in mg per  unit  area of total
contamination (measured  as  non-volatile residue).   These standards are
empirically  developed and  operationally justified,  for specific  applications.
They vary from country to country and  application to application.  In the
United States the generally accepted standards  of cleanliness  for military,
aircraft, and hospital applications is 3.0  mg/sq. ft.; for NASA  space
applications the standard is 1.0 mg/sq. ft.; and  for industrial  applications
it is 10-50 mg/sq.ft.  Standards and test methods are  specified  in American
Standard Testing Methods (ASTM-G63 for evaluating nonmetallic  materials,  -G88
for designing systems, and  -G94  for evaluating  metal materials),  Compressed
Gas Association (CGA), Department of Defense (DOD), NASA (SN-C-0005), Society
of Automotive Engineers  (SAE), and other documents.  These standards are
empirically  developed,  operationally  justified for specific  applications.
However, they may be too low or  too high for unique applications with atypical
conditions such as rapid changes in temperature or  pressure or unusual
electrostatic potential.

      Solvents such as non-ozone depleting  chlorinated solvents  and
hydrocarbons often clean satisfactorily, but all  have*  environmental or
toxicity concerns, and some have flammability concerns.  Environmental, worker
safety, and flammability concerns are  addressed when cleaning choices are made
for specific systems.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      Traditional cleaning with CFC-113 and 1,1,1-trichloroethane (scheduled
for production phase-out under the Montreal Protocol) is only sustainable
using stockpiles or new production under terms of the Montreal Protocol's
Essential Use Process.  Historically verified cleaning with chlorinated
solvents is possible in some circumstances where worker exposure can be
mitigated, but not for applications in confined spaces and for certain life
support systems.  New solvents such as HCFCs and HFCs may be appropriate for
some of these situations, but the problem of performance and safety has not
yet been verified for all applications and HCFCs are scheduled for phaseout
after 2000.

      Aqueous cleaning options have been successfully developed and
implemented for many oxygen system cleaning situations.  For example, Lockheed
uses aqueous processes in the manufacturing and maintenance of aircraft and
missile oxygen systems, the Air Force uses aqueous cleaning for some aircraft
oxygen system maintenance, NASA/Kennedy Space Center uses aqueous solutions
for cleaning oxygen bulk storage and transfer systems for rocket motors, and
the U.S. Navy uses aqueous cleaning processes for cleaning the tubing in
oxygen systems on ships and submarines.

      Aqueous cleaning of oxygen systems often requires enhancement for
cleaning efficiency thrpugh means such as ultrasonics, increased temperature,
spray, or aggressive flushing.  The performance of each option must be
verified to the particular application.  It is also important to verify
supplier claims and monitor quality assurance.

      Isopropyl alcohol  (IPA) is being used by Lufthansa German Airlines to
clean the oxygen systems in.their commercial aircraft fleet.  Sweden has
reported using a solvent blend for oxygen system cleaning consisting of 95%
ethanol.                                                   .                 .

      Some parts of oxygen systems can be changed to simplify or avoid the
necessity of cleaning or they can be adapted to allow aqueous cleaning.

      Some oxygen system components still depend on CFC or chlorinated solvent
cleaning because current alternatives and substitutes are not technically
suitable.  In other cases, rigid specifications and requirements may need to
be changed from prescriptive to performance standards to allow technically
feasible solutions to be used.  For example, anodized parts that are dyed for
visual identification may fade with certain aqueous cleaning processes.
Anodized surfaces have also been attacked by heated aqueous solutions.
Components and systems with complex geometries may trap fluid or have voids
and spaces where high surface tension cleaners cannot remove soils.  Thus, a
particular aqueous process will not be appropriate for all situations, but it
is possible to select an aqueous system to clean many oxygen systems and sub-
systems .

      Some parts of oxygen systems can be changed to simplify or avoid the
necessity of cleaning or they can be adapted to allow aqueous cleaning.  For
example:

      Option 1:  By-pass service ports can be added to equipment to allow
      pressure gauges to be calibrated in-place rather than through removal
      .and subsequent calibration which increases the chance of gage
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     9-22

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      contamination and system contamination through opening which  thus  often
      leads to cleaning.

   '   Option 2:  Replace pressure gauges with new gauges at frequent  intervals
      to avoid the current practice of cleaning and calibrating at  fixed
      intervals, thereby eliminating the need for maintenance cleaning.

      Option 3:  Send the gauges to central cleaning facilities that  can use
      alternative cleaning processes.

      Option 4:  Replace the difficult-to-clean blind 'tube bourdon  tube  gauges
      with- transducer or liquid filled, sealed-tube gauges which are  both much
      simpler to clean.  Other changes such as eliminating or changing paint
      and dyes that are incompatible with aqueous cleaning may also help
      facilitate cleaning without CFCs.                              '     .

      The selection of any cleaning process requires careful evaluation  of
toxicity and the possibility of exposure controls, of the new residue that may
be introduced by the cleaning fluids, of the suitability of test procedures
for quantifying-the allowable concentrations of new residues, and of  the new
challenges of a new cleaning process such as rinsing, removing the bulk
chemical or water from the surface of components, and drying.

      Screening of substitutes and alternatives also involves cleaning and
drying performance, ,cost, materials compatibility  of the cleaner and
residues, consideration of worker health and safety, and evaluation of proper
disposal of waste so.ils and cleaners.

      Implementation may require re-qualification in the operational
environment, careful training of cleaning personnel, effective testing for.
quality and continuous vigilance to confirm that suppliers meet strict product
requirements.                                                              '
9.15  CORRECTION FLUIDS               •

      Traditionally, 1,1,1-trichloroethane has been.used as a carrier  for
whitener in correction fluids.  Currently, formulations are available  that use
water or petroleum distillates as an alternative.
9.16  FABRIC SPOT REMOVER  •

      In some areas, ODSs such as  1,1,1-trichloroethane  and  carbon
tetrachloride are used as a spot remover  for  the  treatment of  fabrics.
Alternatives include hydrocarbons  and  perchloroethylene.
9.17  PROCESS SOLVENTS

      Ozone-depleting solvents  such as  1,1,1-trichloroethane  and  carbon
tetrachloride are used  in  the process industries  (e.g., pharmaceutical,
chlorinated rubber, silicone manufacturing,  chlorine  production).   Some
alternatives are available as identified  in Appendix  I.   The  sector,  however.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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requires  further in-depth review which is planned under the  auspices of the
United Nations Environment  Programme (UNEP)  Technical Options  Panel.
                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                    •   9-24

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                                  CHAPTER 10

       ALTERNATIVES TO OZONE-DEPLETING SOLVENTS IN DEVELOPING COUNTRIES
10.1  INTRODUCTION

      Solvents account for approximately 15% of the ozone depletion.potential
of chemicals targeted for phaseout under the Montreal Protocol.  This category
includes CFC-113 (chlorofluorocarbon-113), TCA (1,1,1-trichloroethane; methyl
chloroform), carbon tetrachloride, and some HCFCs (hydrochlorofluorocarbons).
Most of these solvents are used in the manufacture of electronics products;
for precision cleaning; to clean metal .parts before further processing; and  as
carriers for solvating agents,' lubricants, adhesives, and specialty coatings.

      Progress in achieving the phaseout has been excellent in  this sector,
given the widespread use of ozone-depleting solvents and the variety and
complexity of their applications.  Of the various uses, the electronics
industry has progressed furthest towards a complete phaseout.   Full phaseout
for metal cleaning applications is hampered by the large number of small
users, many of whom are undercapitalized.  In precision cleaning applications,
users have been aggressively implementing alternatives.  Yet, in some cases-,
they are still searching for solutions for cleaning precision parts that are
especially vulnerable, to residues or reactivities, or that have, unusually
stringent cleanliness criteria.
10.2 . SUBSTITUTES AND ALTERNATIVES

      Substitutes for CFC-113 and TCA of commercial interest include:

      •     No-clean electronics.
      •     No-clean metal finishing/fabrication/assembly
      •     Aqueous cleaning
      •     Semi-aqueous cleaning
      •     Hydrocarbons and derivatives or oxygenated organic solvents
      •     Trichloroethylene, perchloroethylene, and dichloromethane
            cleaning
      •     Halogenated aromatics (monochlorotoluene/benzotrifluorides)
            Cleaning with hydrochlorofluorocarbons  (HCFC-141b, HCFC-225)
      •     Cleaning with perfluorocarbons (PFCs) or hydrofluorocarbons
            (HFCs)       '            • '
      •     Cleaning with dibromomethane
      •     Cleaning with volatile methyl siloxanes
      •     Supercritical fluid cleaning
      •     Carbon dioxide snow cleaning .
      •     Plasma cleaning
      •     Ultraviolet/ozone cleaning
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     10-1  •

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       10.2.1      No-Clean  Electronics

       Eliminating cleaning  (no-clean)  is.the  preferred choice  of all the
 options  that -are available.   Its  current  use  is  extensive  in electronics
 applications.  Moreover  it  is now becoming  available  in metals preparation -
 better lubricants (e.g.  ones  that can be  re-used and  re-captured;  dry film
 lubricants) and more efficient processes  that permit  elimination of,  or
 reduction  in,  cleaning.

       In electronics manufacturing,  the adoption of no-clean technology often
 requires upstream investment  to ensure cleanliness.   For example,  board
 suppliers  to the assembly house,  whether  captive or contract,  must often
 (depending on  board complexity) improve their pre-packaging  cleanliness and
 packaging  quality in order  to assure that no  packaging particulates are
 dropped  on the surface of the board  during  shipping and handling.   This step
 is necessary because the board will not be  cleaned after unpacking.   Since the
 packaging  material is normally conductive,  contamination on  the boards  from
 conductive particles can be deleterious.

       Often, there is a need  for  the installation of  precise flux  application,
 along  with a need for a  corresponding means to measure and control this part
 of the process.  There exists relatively  low  cost, effective technology for
 this part  of the soldering process, which the International  Cooperative for
 Ozone  Layer Protection (ICOLP) has available  through  Northern  Telecom's fluxer
 and tester design.

 Advantages:    _  This process change eliminates the  need  for  cleaning
                  chemicals - a pollution prevention  approach  that can  lower
                  chemical use and waste  production.   It is  a  very simple
                  process that has particular application  in the manufacture
                  of consumer electronics.  It saves  costs and/or  is  cost
                  competitive.

 Disadvantages:     More sophisticated industrial  and military products may
                  require stricter adherence  to  cleanliness  standards for
                  board fabrication.  Sophisticated products require
                  significant technical expertise.  So far,  it is  mostly used
                  during printed  circuit  board assembly.   In metal working,
                  processing and  handling procedures  can be  improved, which
                  can reduce or eliminate the need for cleaning.   Very  often,
                  however, either the primary or the  secondary soil  to  be
                  removed is particulate  matter.  If  particulates  are one  of
                  the soils, no-clean is  not  an  effective  technology  option.
                  Also, use of the "bare  minimum" to  maximize  effectiveness of
                  vanishing oil causes major  risk to  tool  lifp.  Some tools
                  are very costly.  For example,  connector tools can  run as
                  high as $100,000.  Some vanishing oils may have  associated
                  volatility or Global Warming Potential (GWP)  issues.

      10.2.2      No-Clean Metal  Finishing/Fabrication/Assembly

      Elimination of cleaning steps from  the  finishing fabrication and
assembly areas  is a preferred option if applicable.   There are several
possible opportunities to consider no-clean technologies.  In  some instances
it may be practical to just eliminate one or  mare'of  the cleaning  steps.   This


                   * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 step  is  practical  if a part is  cleaned more than once during manufacture or is
 cleaned  again  after  it is  assembled. '  Another possibility is to utilize
 alternative processing fluids for cutting,  drawing,  or machining metal parts.

      Vanishing  oils are one of these  methods.   A vanishing oil is  a very
 light weight oil,  usually  with  a very  low molecular  weight.  It evaporates from
 the part after the cutting or machining operation and before an operation that
 it might interfere with.   An example of this process would be where a part is
 stamped  out and  then held  in inventory for  several hours  or even days before
 it is used in  the  next operation.   The next operation may even enhance the
 evaporation of the lubricant, such as  annealing ovens,  or other heated
 operation.  Many of  the vanishing oils evaporate quite rapidly (within a few
 hours),  and will therefore not  interfere with subsequent  machining  operations.
 In some  cases, it  might be possible to utilize  a lubricant that is  beneficial
 for the  downstream application,  or one that does not require removal.   Many
 ferrous  metal  working operations clean parts then apply a rust preventative
 material to the  part to inhibit rusting during  storage or transportation.   It
 is very  possible to  eliminate the  cleaning  operation and  use the machining
 lubricant as the corrosion preventative,  or apply the corrosion preventative
 without  cleaning off the lubricant.  Usually the part is  cleaned again when it
 is ready to be used  in the final assembly.   Although cleaning is not always
 completely eliminated,  one or more cleaning operations are eliminated.

 Advantages:        This process  change  can eliminate  the need for cleaning
                   chemicals - a pollution prevention approach that  can lower
                   chemical use  and waste production..  It  is  a very  simple
                   process  that  has particular application in many metal
                   finishing applications.
                   /
 Disadvantages:     There may be  many hidden  costs associated  with the use of
                   no-clean technologies.  Increased  tool  wear often occurs
                   with the use  of  vanishing oils,  as they are not very
                   viscous.   Also,  in many operations,  there  is  a need for
                   clean parts for  quality control measurements.   If a cleaning
                   operation is  eliminated for production,  a  method  of cleaning
                   for  testing needs to be implemented.

                   A  second disadvantage is  that many manufacturers  are
                   required to clean parts to a  specification set by the
                   customer.  The customer will  need  to change the acceptance
                   specifications that .they  are  currently  utilizing.   This can
                   be very  difficult in today's  environment of quality
                   suppliers and just-in-time manufacturing.

      10.2.3       Aqueous  Cleaning

      Aqueous  cleaning uses water  as the primary cleaning medium, but often
detergents (saponifiers) and other chemicals.are added to enhance cleaning
performance.                      .                         •

Advantages:         Aqueous  solvent  and  added chemicals generally have low
                   toxicity and  the cleaning power is good for most  soil's.
                   Chemical costs are low, and there  are lower materials losses
                   compared with other  cleaning  processes.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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Disadvantages:
      10.2.4
 Effluent  treatment or recycling may be necessary,  and drying
 needs  may require new capital intensive equipment and result
 in higher energy costs.   It is not always possible to use
 aqueous cleaning on water sensitive substrates or on complex
 geometries.   Aqueous cleaning solvents are more time
 consuming than other methods.  Moreover aqueous cleaning may
 require-more floor space,  and' it m'ay not be effective on
 high viscosity linear hydrocarbons, asphaltic, micellar or
 carbonaceous oils..  Strongly corrosive (acidic or basic)
 aqueous cleaning chemicals can require the use of protective
 gear to reduce exposure  due to acute toxic potential.or.
 chronic effects.   Also,  water consumption can be high - up
 to 10  gallons per minute (gpm),  unless water is recycled,
 which  can be a factor in limited water supply or
 environmentally sensitive situations.

•Semi-Aqueous Cleaning
      Semi-aqueous cleaning is also a water-based cleaning process that uses
relatively low molecular weight organic chemicals to enhance cleaning
performance.  Semi-aqueous processes include the addition of chemicals such as
terpenes.
Advantages:
Disadvantages:
 Semi-aqueous  solvent cleaners are generally stronger in
 solvency 'than aqueous cleaners because their organic portion
 aids  in dissolving organic contamination.   The chemicals
 used  in semi-aqueous processes have low toxicity,  although
 their toxicity can be higher than that of the chemicals used
 in aqueous  cleaning processes.  Semi-aqueous processes offer
 good  cleaning power for most soils; waste minimization is
 possible through water reuse, and residual concentrated
 wastes can  be used as cement kiln fuel.   Semi-aqueous
 solvents exhibit a low vapour pressure,  so only small
 quantities  are lost to evaporation.

 All degreasing solvents and the organic constituents of
 blends are  volatile, and may require•control measures in
 accordance  with national,  regional, and local regulations,
 as well as  corporate policy.  These control measures address
 concerns over environmental, health, and safety issues.
 Effluent treatment is likely since soluble solvents
 generally have very high biological oxygen demands (BODs),
 requiring solvent disposal.  Flammability and emulsion
 stability may be an issue in some cases.  The drying
 requirement are similar to those of aqueous cleaning,
 possibly requiring new, capital intensive equipment and
 incurring higher energy costs compared with some other
 options. . It  is not always possible to use aqueous or semi-
 aqueous processes on water sensitive substrates or on
 complex geometries.  Moreover this process may require more
 floor space,  as well as high capital expenditure.   Water
 consumption can range up to 2-3 gpm, which, can be a factor
 in limited  water supply or environmentally sensitive
 situations.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
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       10.2.5       Organic  Solvent Cleaning (alcohols,  aliphatics.  ketones.
                   aldehydes, .and blends  or C1-C20.  hydrocarbons and
                   derivatives)

       Organic  solvent  cleaning  provides  another alternative to ozone-depleting
solvents.  Alcohols, aliphatics,  ke'tones,  aldehydes,  and mixtures  of these
chemicals can  be used.  As  with other  options,  they have advantages and
disadvantages.
Advantages:
Disadvantages:
      10.2.6
Organic solvents have good cleaning power  and  are
comparatively simple to use.  Process cleaning times  are
shorter than aqueous or semi-aqueous cleaning.  Most
contaminated solvent can be easily filtered and distilled,
with proper equipment, for reuse.  They are also cost
competitive.

All degreasing solvents and the organic constituents  of
blends are-volatile and may require control measures  in
accordance with national, regional, and local  regulations,
as well as corporate policy.  These control measures  address
concerns over environmental, health, and safety issues.
Most organic solvents are also flammable and/or combustible.'
For these reasons, special equipment and facilities may be
required to ensure protection of worker health and safety.
In these cases, capital intensive expenditures  will arise.
In addition, precautions for waste disposal are necessary.
Some organic solvents are unsuitable for use on plastic
parts, and low-volatility solvents are difficult -to dry,
especially on complex, geometries.

Chlorinated Aliphatic Solvent Cleaning (trichloroethylene.
perchloroethylene or dichloromethane1)
      Trichloroethylene, perchloroethylene,  and  dichloromethane  do  not  deplete
the ozone layer and can be used as alternatives  for  cleaning.
Advantages:
Disadvantages:
These non-ozone-depleting halo'genated solvents have
potentially high cleaning properties for oils, greases and
some other organic soils; they are nonflammable and non-
corrosive to most materials; and they are'simple to use.
They offer low operating costs, and it is sometimes possible
to retrofit existing equipment at low cost.

All'degreasing solvents and the organic constituents of
blends are volatile, and may require control measures in
accordance with national, regional, and local regulations as
well as corporate policy.  These control measures address
concerns over,environmental, health, and safety issues.  In
addition, special materials and waste handling practices are
necessary.  Moreover, good waste management practices should
be implemented in order to prevent accidental releases to
soils and groundwater, which may result in expensive long-
term clean-up costs.  Newer vapour-tight machines or
equipment with vapour-emission controls offer more
assurances of worker safety, but at a significantly higher
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      10-5

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      10.2.7
cost.  Chlorinated solvents may be unsuitable for use on
some plastics.  High boiling point solvents  (e.g.
perchloroethylene) may be uneconomic in vapour degreasing
operations due to energy costs.

Chlorinated Aromatic Solvent Cleaning
(monochlorotoluene/benzotrifluorides)
      Monochlorotoluenes/benzotrifluorides are a new option.  They have good
solvency properties, but they have a low suggested occupational exposure limit
(30 ppm).
Advantages:
Disadvantages:
      10.2.8
Monochlorotoluenes/benzotrifluorides have the advantage of
good cleaning potential.  These chemicals also form miscible
solvent blends,  and some are nonflammable.

All degreasing solvents and the organic constituents of
blends are volatile and may require control measures in
accordance with national, regional, and local regulations,
as well as corporate policy.  These control measures address
concerns over environmental, health, and safety issues.  As
with.the other non-ozone-depleting solvents, there is the
possibility of contamination of soils and groundwater from
spills and accidental discharges which can result in
expensive long-term clean-up costs.  Some products,
especially if contaminated with soils, may emit highly toxic
by-products in the event of accidental fire or incineration.
This group of chemicals is not yet authorized in the United
States for use as replacements for ozone-depleting solvents.

Hvdrochlorofluorocarbons (HCFC-123. HCFC-141b. HCFC-225)
      HCFC-123 and HCFC-141b are now sold in most markets.  HCFC-225,
available in some markets now, will be fully available in 1995, except where
expressly forbidden by ozone layer protection legislation.  These HCFCs are
good cleaners for certain specialized applications and can be blended with
other solvents such as alcohol for suitable cleaning performance.  The U.S.
Environmental Protection Agency (EPA) has banned the use of HCFC-141b as a
solvent in all cases effective January 1, 1996.  Limited exemptions may be
granted for replacement of CFC-113 where no other alternative exists.  In
Sweden all uses of HCFCs in solvent operations were banned as of 1 January
1994.
Advantages:
Disadvantages:
These HCFCs have cleaning power comparable  to CFC-113  and
they are nonflammable  (in most applications).  HCFC-225
shows good compatibility with plastics, elastomers  and
metals, and has a low  ozone-depleting potential'(ODP)
relative to HCFC-141b  (.025-.033 ODP depending on the  blend
of the ca and cb isomers).  HCFC-225 can be used in existing
retrofitted cleaning equipment.  HCFC;141b  also  has a  low
toxicity.

All HCFCs have the disadvantage of being ozone-depleting
substances, albeit with lower ODPs than CFC-113, and thus
are transitional substances in some uses.   HCFC-141b has a
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      10-6

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                   low boiling  point,  a  relatively  high OOP (.11)  and damages
                   plastics  and elastomers.  HCFC-225  is more  expensive  than
                   HCFC-141b.   All  of  the  toxicblogical testings  of HCFC-225ca
                   and HCFC-225cb planned  under the Programme  for Alternative
                   Fluorocarbon Testing  (PAFT)-IV were completed  by early-1994.
                   Based  on  these. PAFT results,  the.acceptable exposure  limit
                   (AEL)  of  the commercially available HCFC-225 blend has  been
                   set at 50 ppm (8hr-Time Weighted Average) by a manufacturer.
                   All degreasing solvents and  organic constituents of blends
                   are volatile, and may require cpntrol measures  in accordance
                   with national, regional, and local  regulations,  as well as
                   corporate policy.   These control measures address concerns
                   over environmental, health,  and  safety issues.   Special low-
                   emissions equipment,  which is now commercially available,  is
                   essential for environmental  protection and  solvent usage
                   cost reasons.  Retrofitting  of existing equipment to  utilize
                   HCFC-225  may require  additional  freeboard,  automated  lid and
                   hoist  emission controls, and replacement of pump seals  to  .
                   prevent excessive emissions.  Because HCFCs are transitional
                   in nature, a second shift from HCFCs to'a non-ODS
                   alternative  wiLl  ultimately  be required.  It may.be more
                   cost effective to move  immediately  to the non-ODS technology
                   to avoid  the costs  of changing the  cleaning process twice,
                   if possible.  Good  management of wastes is  also recommended!

                   Important note:   HCFC-lAlb has a high ozone depletion
                   potential (OOP)  of  0.11, which is equivalent to the TCA OOP
                   of 0.12,  and is  controlled under the Montreal  Protocol.
                   Future changes may  further restrict its use or  advance  its
                   phaseout  dates.   HGFC-141b should therefore only be
                   considered as a  replacement  for  CFC-113 in  specialized
                   applications where  no other  alternative exists.   It should
                   never  be  considered as  a replacement for TCA.

      10.2.9       Perfluorocarbons  (PFCs)           .

      Perfluorocarbons (PFCs)  are  a subject of increased interest over  the
last year, especially for cleaning precision-engineered parts.  An atmospheric
lifetime of greater than 500 years  means  that  PFCs have a significant direct
global.warming potential.   The US  EPA Significant  New Alternatives Program
(SNAP) allows the  use of PFCs  in electronics and precision cleaning
applications only  where  users  can  prove that,  due  to  performance  or safety
requirements, no other technically feasible alternative exists.   Sweden is
reviewing the use  of PFCs,  as  an alternative to ODSs,  to be permitted only
with waivers after January  -1,,  1996.

Advantages:      ,  PFCs are  not ozone-depleting substances and should be
                   allowed for  special precision cleaning applications,  such as
                   oxygen systems,  nuclear triggers, and electromechanical
                   gyroscopes.   PFCs are non-flammable and of  low toxicity.
                   They are  good rinsing and drying agents.  Furthermore,  they
                   are very  stable  molecules and will  not attack  non-fluorine
                   containing substrates.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 Disadvantages:
      10.2.10
On the other hand, PFCs are  a poor  solvent,  thus  they  must
be used with other more effective solvent  cleaners.  All
degreasing solvents and the  organic constituents  of blends
are volatile and may require control measures  in  accordance
with national, regional,•and local  regulations, as well as
corporate policy.  These control measures  address concerns
over environmental, health,  and safety  issues.  PFCs are
expensive to purchase and they have an  extremely  high  global
warming potential.  PFCs should only be used as a
transitional substance in special applications.   The World
Bank may request that project applications using  PFCs
demonstrate adequate emission reduction capabilities in
their equipment.  New equipment will usually be required.

Important note:  PFCs may be controlled internationally or
nationally to protect against climate change.  They are not
recommended for financing under the Montreal Protocol.

Hydrofluorocarbons (HFCs)
      HFC solvents are likely to be commercially available within  two years.
The key environmental characteristic of concern is their long atmospheric
lifetime.
Advantages:
Disadvantages:
      10.2.11
HFC solvents are non-flammable and of low toxicity.  They
are better solvents than PFCs, and their behaviour is
analogous to CFC-113 in a manufacturing setting, due to
similar physical properties.  HFCs are the probable drop-in
replacement for. the use of PFCs.  The availability of HFCs
is limited now, but several companies have plans for
commercial production soon.

HFC solvents are likely to be expensive and toxicity testing
is not complete.  Toxicity of HFCs is expected to vary
depending on their chemical structure.  Due to low solvency,
they may need co-solvents to be used in solvent blends or in
solvent/solvent systems.  These systems are non-ODS, low-
GWP, and of low toxicity.  They have moderately long
atmospheric lifetimes (approximately 20 to 30 years), thus
they have moderately high global warming potentials.  All
degreasing solvents and the organic constituents of blends
are volatile and may require control measures in accordance
with national, regional, and local regulations as well as
corporate policy.  These control measures address concerns
over environmental, health, and safety issues.

Important note:  May be controlled internationally or
nationally to protect against climate change.  Not
recommended for financing under the Montreal Protocol.

Dibromomethane
      Dibromomethane (a component of a proprietary product) is a new
substitute that entered the market in 1993.  Its cleaning power is yet
unproveri.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     10-8

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 Advantages:        Dibromomethane is being offered as a drop-in replacement for
                   CFC-113,  which would be an advantage where expensive
                   cleaning equipment is in place.

 Disadvantages:     Dibromomethane has a relatively high ozone depleting
                   potential (ODP) and its cleaning power is unproven.  It is
                   likely to be more toxic than methylene chloride
                   (dichloromethane),  have a high probability of forming
                   hydrogen bromide and other toxic substances if near a heat
                   source,  and its high boiling point (97°C) renders is an
                   unlikely candidate for use with non-metallic parts.  Also,
                   it contributes to photochemical  smog.   All degreasing
                   solvents  and the organic constituents  of blends are volatile
           (        and may require control measures in accordance with
                   national,  regional,  and local regulations,  as well as
                   corporate policy.  These control measures address concerns
                   over environmental,  health,  and safety issues.   Since
                   dibromomethane is an ODS,  it should not be listed as an
                   alternative.   It is  considered unacceptable by the U.S. EPA.

                   Important note:   Dibromomethane  is not recommended for
                   financing under the  Montreal Protocol.

       10.2.12     Volatile  Methyl Siloxanes  (VMSs)

       This is another new substitute  that entered  the market in 1993.   I.  has
been used  in  the past in cosmetics.   It use  is of  particular interest
especially for  cleaning silicone-based fill  fluids in guidance
.instrumentation.   VMSs should be allowed for special cleaning applications,
however their use  is  expected to be infrequent.

Advantages:        VMSs have  low toxicity.  VMSs  are one  of the few solven-ts
                   that are  chemically  compatible-with silicone fluids.

Disadvantages:     VMSs are  expensive.   Controls  for flammability  may be
                   necessary  and some  formulations  have.low suggested
                   occupational  exposure limits.  All degreasing solvents  and
                   the organic constituents of  blends are  volatile,  and may
                   require control  measures in  accordance  with national,
                   regional,  and local  regulations,  as well as corporate
                   policy.  These control measures  address concerns  over
                   environmental,  health,  and safety issues.  They  have  limited
                   applicability.

                   Important  note:   VMSs are  not  yet -proven suitable for
                   financing  under  the  Montreal Protocol.

       10.2.13      Supercritical Fluid  Cleaning (SCF)

       Supercritical fluids,  especially carbon  dioxide, have been  used for more
than a decade to selectively remove, chemical components  from  processed foods,
coffee, hops, and  tobacco.   Two of the most  common uses  are  to de-caffeinate
coffee beans, and  remove  cholesterol from eggs.            .
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Advantages:       This alternative is environmentally benign.  SCFs have
                  liquid-like densities combined with the beneficial transport
                  properties of gases, such as low viscosity and high
                  diffusivity.  Also, without surface tension limitations,
                  SCFs can penetrate small spaces and are therefore very
                  useful for cleaning complex geometries.  Carbon dioxide  is
                  additionally advantageous because it is non-flammable,
                  environmentally acceptable, inert, non-toxic, recyclable,
                  and low in cost.

Disadvantages:     Only limited applications have been proven so far.  In
                  general, hydrophobic contaminants, such as oils, dissolve
                  well in supercritical C02.   Hydrophillic contaminants, such
                  as inorganic salts, have little solubility.  There are high
                  start-up costs that require extra operator training.
                  Equipment to be used with supercritical fluids is capital
                  intensive because of the high gas pressure required to
                  operate the process.

      10.2.14     Carbon Dioxide Snow Cleaning

     , CO, snow is a relatively new cleaning technique that can be used to
replace CFC-113 and TCA in a variety of cleaning applications.  During
cleaning, C02 snow is directed toward the contaminated surface.   Cleaning
occurs as a result of the momentum transfer between the solid C02 particles
and particulate contamination.  The collisions loosen the particulates from
the surface,  and the gaseous C02 sweeps them away.

Advantages:       Carbon dioxide snow cleaning is an inexpensive method of
                  removing particulates from surfaces.  This is a good
                  replacement for the use of CFC-113 as a dusting agent on
                  optical surfaces.

Disadvantages:     Carbon dioxide at ambient pressure does not exhibit good
                 . solubility properties and it is unlikely that it could be
                  used as a solvent cleaner.  Another disadvantage of carbon
                  dioxide snow is that it is much colder than CFC-113 and may
                  cause moisture to condense from the air onto the part being
                  cleaned.  Carbon dioxide has a global warming potential and
                  its use would be a net contribution to climate change unless
                  it has a source that would otherwise be an immediate
                  emission.  However, most carbon dioxide is scavenged from
                  emissions and thus makes no net contribution to climate
                  change.

      10.2.15     Plasma Cleaning

      Plasma cleaning may have benefits in the metal cleaning industry equal
to the benefits of "no-clean" processes in the electronics industry.  Plasma
cleaning, especially oxygen, has been used for many years in the electronics
industry for the removal of oxides from electronic components prior to
adhesive bonding.  In recent years, larger pieces of equipment have been used
to remove organic contamination from aircraft wings and mechanical devices.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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Advantages:
Disadvantages:
      10.2.16
The low pressure process is environmentally sound because
the waste products are combustion by-products of the organic
contamination, usually of very small quantity.  Since the
plasma acts like a gas, the cleaning ability is independent
of the geometry of the part to be cleaned.  Plasma cleaning
could be the primary method of .cleaning metallic parts in
the future.  Plasma cleaning is more environmentally sound
than the use of aqueous or organic solvents.

Plasma cleaning cannot be used on components that are
plastic, rubber, or contain other carbon-based materials.
Also, it is often used with many potentially harmful gases
and mixtures which could ionize and recombine to form by-
products even more detrimental than the original plasma.

Ultraviolet/Ozone Cleaning:
      The ability of ultraviolet  (UV) light to decompose organic molecules has
been known for a long time, but it is only during the past decade that UV
cleaning of surfaces has been explored for commercial applications.  UV/ozone
cleaning is primarily the result of photosensitized oxidation processes.  The
contaminant molecules.are excited and/or'dissociated by absorption of short-
wavelength UV light.  Atomic oxygen and  ozone are produced simultaneously when
02 is dissociated by the absorption of UV with wavelengths less than 245.4 nm.
Atomic oxygen is also produced when ozone is dissociated by the use of the UV
and longer wavelengths of radiation.  The- excited contaminant molecules, and
the free radicals produced by the dissociation of the contaminant molecules,
react with atomic oxygen to form simpler, volatile molecules such as C02, H20,
and Np.   The UV/ozone cleaning procedure is widely used in cleaning prior to
thin film deposition in the crystal industry.
Advantages:
Disadvantages:
The process is environmentally safe, yielding non-ozone -
depleting products and, of course, not involving any ozone-
depleting substances in the process.  The UV/ozone cleaning
procedure has been shown to be highly effective in removing
a variety of contaminants from surfaces.  Examples of
contaminant effectively removed from surfaces include human
skin oils, cutting oil, rosin mixtures,  lapping compound,
vacuum pump oil, DC-704 and DC-705 silicone diffusion pump
oil, and rosin flux from rosin-core lead-tin solder.

Another advantage is that the process is inexpensive, not
requiring elaborate apparatus construction or waste product
disposal.  Depending on the size of the cleaning
requirement, few safety features need to be considered.
Commercial equipment is available for smaller applications.
The UV/ozone chamber also acts as an excellent storage
facility for cleaned substrates, preventing any subsequent
organic surface contamination.  The procedure produces clean
surfaces at room temperature.

The primary disadvantage to UV/ozone cleaning is that thick
contamination cannot be effectively removed from substrates.
The optimum result is obtained when thin film contamination
is present.  This requires pre-cleaning before final
                    * 1994' UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     10-11

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                   cleaning.  UV/ozone  does  not remove  particles  from surfaces
                   unless  these  particles  are  organic in composition.   The
                   generation of ozone  in  the  procedure may be  a  safety
                   consideration,  and the  apparatus, depending  on size,  needs
                   to be placed  in an exhaust  hood or other similar exhausting
                   system.
 10.3  TECHNOLOGIES FOR DEVELOPING  COUNTRIES   '

     . The alternatives to  ozone-depleting  solvents used by. the  electronics,
 precision cleaning,  and metal  degreasing industries have been ranked in order
 of greatest commercial interest based  on environmental effects  and on the
 possibility of  their use in  developing countries.

      The selection  of the alternative should be based on  five  primary
 factors.  The alternative:   1.  should  not  be an ozone-depleting substance,  2.
 should enable the enterprise to maintain a product reliability  level at lea'st
 equal to the past methods, 3.  should be economical, 4. should not  create
 significant environmental  problems, and 5. should not compromise worker or
 consumer health and  safety.

      Emerging  technologies  such as HFCs and VMSs are not.  recommended for
 implementation  and financing until their toxicity, technical, and  economic
 performances are established.   Super critical fluid cleaning  (SCF),  plasma
 cleaning, and ultraviolet  ozone cleaning are recommended for  use and financing
 under the condition  that they  can be shown to be cost effective, even though
 they have low environmental  impact, because they are mostly used for specialty
 applications, and because  of specialized engineering and training
 requirements.'  Other emerging  technology,  such as dibromomethane solvents,  are
 not recommended for  implementation and financing until they are developed
 further.  Chlorinated solvents  should  only be used where exposure  to workers
 can be controlled within allowed limits.

      In order of preference,  then, the alternatives that  should be  considered
 for developing countries are:

      Tier 1:     No-clean, keep-clean
      Tier 2:    .Aqueous/semi-aqueous cleaning
      Tier 3a:    Organic  solvent cleaning (with solvents  having toxicities
                  less than non-ozone-depleting halogenated.solvents)
      Tier 3b:    Non-.ozone-depleting  halogenated solvents
      Tier 3c:    Organic  solvent cleaning (with solvents  having toxicities
                  greater  than non-ozone-depleting halogenated  solvents)
      Tier 4a:    HCFC-225 and HCFC-123
      Tier 4b:    HCFC-141b
      Tier 5:     PFCs                                             '

      Some comments  on each of  these alternatives should be considered in
 deciding which is more appropriate for each cleaning application.

      All applications to  the Fund that propose the use of aqueous  or semi-
 aqueous cleaning should include funding for recycling, waste  water  treatment,
 and drying equipment.  Applications that involve the use of organic  and
hydrogenated solvents should include containment equipment, adequate


                    * 1994- UNEP  SOLVENTS, COATINGS, AND ADHESIVES REPORT  *
                                     10-12

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 ventilation control,  and/or low emission equipment.   The guidelines should
 include  requirements  for personnel safety,  for example,  the use of eye guards
 by  workers  who  perform the cleaning operation.

       10.3.1      No-Clean

       No-clean  is  the recommended option for the  manufacture of consumer
 electronics,  and it is a preferred option for the manufacture of more
 sophisticated printed wiring assemblies.   To ensure  success however,  no-clean
 processes require  skilled operators,  increased control of incoming part
 quality, and superior machinery due to  narrow operating  windows and time to
 prove  its reliability of hardware produced with the .technology.

       10.3.2      Aqueous/Semi-Aqueous  Cleaning

       Aqueous and  semi-aqueous  cleaning technologies, with proper controls and
 monitoring,  are  generally considered  to have low  environmental  impact due  to
 the  low  toxicity of the constituents.   However, poor  housekeeping practices,
 such as  unnecessary dumping of  the cleaning tanks, can cause these cleaners to
 have worse  effects than would ordinarily be expected.  In addition,  if
 effluent is  untreated,  cleaning solution discharges as well as  any hazardous
 soils  could cause  environmental problems.   In an  area with water  management or
 water  supply problems,  aqueous  cleaners may be  a  poor choice unless  efficient
 water  recycling  is possible.  Aqueous/semi-aqueous formulations should be
 carefully screened to avoid additives that  are  toxic  to  human health  or may
 cause  synergistic.  toxicity in the environment.  The use  of aqueous  or semi-
 aquepus  cleaning should include funding for drying, recycling,  and waste
 treatment equipment.

       10.3.3    .   Organic  Solvent Cleaning
                      	°        i

      Although toxicity can be  a concern for some formulations, the principal
 risk is  derived  from  the high flammability  of the more volatile compounds.
 Such solvents are  not appropriate for use  in settings with sources of ignition
 unless appropriate  precautions  are taken, and proper  ventilation  and
 individual protective equipment is used.  Similarly,  the  possibility  of soil
 or groundwater contamination is of concern  if proper  materials handling
 practices are not  followed.   Caution should be  used when these  solvents  are
 used with sprays,  heaters,  or ultrasonic  equipment.

      10.3.4       Non-Ozone-Depleting' Halogenated Solvents

      Where emission  issues  are of concern,  emission  control  equipment should
be included-to meet domestic  regulations.   Strict adherence to proper
 industrial hygiene practices  is essential where these solvents  are used
because  their worker  exposure limits are  similar  to organic solvents.   These
 chemicals have intrinsic properties that  point  to the possibility of  human
health and environmental impacts.   However,  new equipment,  although expensive,
 is available  that  can control emissions and therefore significantly  lower
risks.   These chemicals  should  generally be avoided if poor attention to
chemical handling  and waste  disposal procedures is predicted, since
 inadvertent spills  can lead to  unacceptable worker exposure and soil  or
 groundwater contamination.   All of these  chemicals are associated with high .
 start-up costs due  to expensive equipment.   On  the other hand,  non-ozone-
 depleting halogenated solvents  may offer  the lowest operating costs  since  they


                    *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     10-13

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 are the least costly chemicals in the group.   However,  there is a high 'risk of
 contaminating soil and/or groundwater in spite of well engineered and
 maintained systems.   The costs of cleaning up contaminated soil and/or
 groundwater can be substantial.   The Implementing Agencies of the Multilateral
 Fund (United Nations Development Programme, United Nations Environment
 Programme,  United Nations Industrial Development Organisation,  World Bank)
 should consider the cost of monitoring these projects and the cost of
 insurance that could pay for cleanup.

       10.3.5      HCFC-123.  HCFC-225.  HCFC-141b. and PFCs

       HCFC-225 is very similar to CFC-113 in physical and chemical properties,
 and can form azeotropes with alcohols.   They exhibit good materials
 compatibility and can therefore be used to replace CFC-113 with few changes in
 the process.  HCFCs-225 has been used in applications where other alternative
 technologies cannot be applied.

       Because of a high ozone depletion potential (OOP),  HCFC-141b is never
 suitable as a substitute for 1,1,1-trichloroethane.   It is suitable as a
 substitute for CFC-113 only when lower OOP alternatives,  including HCFC-225,
 are not feasible.  Because HCFCs are transitional in nature, a second shift to
,a non-ODS alternative will ultimately be required.  It may be more cost
 effective to move immediately to a non-ODS technology to  avoid the costs
 associated.with qualifying and changing the cleaning process twice, if
 possible.

       PFCs should only be used in electronics and precision cleaning
 applications where no other alternative will provide the  needed performance.
 Low loss equipment is available for PFCs and HCFC-141b, and if either must be
 usedj  this equipment should be used,  PFCs are not likely to be an acceptable
 substitute for manufacturing processes used in developing countries.

       Use practices and local environmental considerations, can move a
 particular chemical either up or down in the selection hierarchy.
 10.4  RETROFITS

       Retrofits for solvent, cleaning applications are not as common as for
 refrigeration or for foam-blowing..  Retrofits' should not be allowed except in
 extraordinary circumstances for adapting solvent cleaning equipment to HCFCs.
 HCFCs  are  ozone-depleting substances and should not be recommended for use in
 retrofits,  unless the equipment is very new aiad is designed to have very low
 emissions  through the incorporation of advanced freeboard designs, chiller
 systems, and adsorption/recycle/destruetion systems.  For current users of
 CFC-113  or TCA solvents as cleaners, the most likely retrofits are to:

       Chlorinated Solvents

             Retrofit of existing .cleaning equipment to chlorinated solvents is
             generally low cost.-  The chemical properties are similar to TCA
             and CFC-113 and chemical costs are significantly lower.  Most
             equipment can be modified to use any of the other chlorinated
             solvents and meet U.S. Occupational Safety and Health
             Administration (OSHA)  or other worker exposure requirements.


                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
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            However, it is expensive and more difficult  to meet  the volatile
            organic compound  (VOC) and Air Toxic requirements.   The U.S.
            Maximum Achievable Control Technology  (MACT)  standards will
            require more investment in equipment retrofit than the OSHA
            standards and possible periodic monitoring,  record keeping,  and
            reporting.  The cost of the retrofit should  include  a period of
            monitoring the vapour emissions of the  replacement chemical  from
            the machine, and  take into account the  costs  associated with
            cleaning up contaminated soil and/or groundwater.  In addition,.
            monitoring on a basis which is possible  in industrialized
            countries may be  difficult to put into  practice  in some developing
            countries.
      HCFC-225
            Since the physical arid chemical properties of HCFC-225 are similar
            to CFC-113, it can be used  in a retrofit application, but is
            recommended only for applications where other, more
            environmentally acceptable  alternatives are not  feasible.
            However, low loss equipment, which Is now commercially available,
            is recommended due to the relatively high cost of HCFC-225.

      HCFC-lAlb       .

            Due to a lower boiling point and high ozone depletion potential, a
            retrofit can be expensive.  Significant degreaser modifications
            must be made, such as adding freeboard, chillers, programmable
            hoists, automatic sliding access ports, and molecular sieves, in
            order to reduce emissions.  Moderately high retrofit costs,
            combined with higher chemical costs, make HCFC-141b a poor
            candidate for retrofits.  Retrofit to HCFC-141b  is not recommended
            for investment.

      Retrofits to aqueous and semi-aqueous cleaning is also possible.
Degreaser tanks are sometimes retrofitted for water based cleaners, but this
requires extensive engineering redesign and should not be attempted without
direct consultation with a qualified equipment supplier.  For semi-aqueous
processes, the chemical manufacturer.must also be consulted.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                                  CHAPTER 11

                      CASE STUDIES OF PHASEOUT'ACTIVITIES
      This chapter includes company case studies providing examples of
successful programmes to eliminate the use of ozone-depleting solvents in
industry.  The case studies discuss the evaluation and implementation of
materials, alternative technologies, and processes to eliminate the use of
CFC-113 and 1,1,1-trichloroethane in cleaning operations.  The following 22
case studies are presented in this chapter:

1)    Allied Signal -- "An Evaluation of Aqueous Technologies at Allied Signal
Aerospace Canada (ASAC)" -- A description of the evaluation of various aqueous
saponifiers.                                      .

2)    AT&T Bell Laboratories -- "AT&T and the Elimination of Ozone-Depleting
Substances" -- A description of the alternative cleaning and manufacturing .
technologies, as' well as no-clean techniques.

3)    Beck Electronics -- "Semi-Aqueous Equipment Conversion at Beck
Electronics" -- A description of the evaluation of more than 20 alternative
solvents and the design and construction of custom cleaning equipment.
Obsolete vapour degreasers were converted to use the new terpene-based
solvent.

4)    Ford Motor Company -- "CFC Elimination in Electronics Soldering at Ford
Motor Company" -- A description of the use of no-clean soldering and nitrogen
inertion in electronics manufacturing.                    •      ...

5)    Hitachi -- "Reduction and Elimination of ODS Solvents at Hitachi" --,A
general overview of the different types of alternatives evaluated by Hitachi.

6)    Honeywell -- "Replacement of Ozone-Depleting Substances in Honeywell
Space and Aviation Control Products" -- A description of,the use of various
alternatives to ODSs including supercritical fluid cleaning, C02 snow,
perfluorocarbon sprays, water-based sprays, and the use of semi-aqueous
processes.

7)    IBM Corporation -- "ODS Elimination at IBM Austin, Texas" -- A
description of the aqueous and no-clean processes implemented in the printed
circuit board manufacturing process.                          . <

8)    Japan Industrial Conference on Cleaning (JICC) -- "The Japan Industrial
Conference on Cleaning" -- A description and history of the JICC, an
information clearinghouse formed to assist Japanese industry in identifying
and evaluating non-ODS solvents.                                    .

9)  .  Lockheed Sanders Company -- "The Elimination 6'f 1,1,1-trichloroethane  in
Electronics Cleaning at Lockheed Sanders Company" -- A description of the
alternative cleaning systems employed to replace 1,1,1-trichloroethane use in
electronic component cleaning.
                    * 1994 UNEP SOLVENTS, COATINGS/ AND ADHESIVES REPORT
                                      11-1  .

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10)   Miljoministeriet  --  "Hydrocarbon Dry Cleaning at Miljoministeriet"  -- A
description submitted by the Danish EPA of the use of an  alternative
hydrocarbon dry cleaning system to replace ODS use in dry cleaning.

11)   Minebea Company -- "Phasing Out of Ozone-Depleting  Substances by  the
Minebea Co." -- A description of implementing an aqueous  cleaning  system  for
the cleaning of ball bearings.

12)   National Semiconductor -- "Elimination of ODSs at National
Semiconductor, Malaysia" -- A description of management and  technical process
from team development through implementation.

13)   Naval Aviation Depot  -- "Elimination of Ozone Depleting  Solvents  at
Naval Aviation Depot Cherry Point" -- A general discussion of  the  program
including a special discussion of hand-wipe cleaning.

14)   Northern Telecom  --  "Northern Telecom and CFC-113 Elimination"  -- A
summary of the steps to eliminate CFC-113 from the program's inception  in 1987
and'including a discussion of the company's efforts to assist  developing
countries through cooperation with ICOLP and UNEP.

15)   Robert Bosch Corporation -- "Replacing Solvent Cleaning  with Aqueous
Cleaning" -- A case study prepared by the Centre for Aerosol Technology
detailing elimination of CFC-113 and trichloroethylene at Robert Bosch
Corporation.

16)   Rockwell International -- "Use of a Low-Residue Flux in  a Military
Electronics Program" -- Qualification of a low-residue flux  on the Hellfire
Missile assembly line.

17)   Seiko Epson Corporation -- "The Cleaning Center System of Seiko Epson
Corporation" -- A description of an information clearinghouse  and  a central
cleaning facility to assist small and medium-sized facilities  in identifying
and evaluating alternatives to ODSs.         .

18)   Singapore Institute of Standards and Industrial Research (SISIR)  -- "The
ODS-Free Verification Scheme for Singapore Industry" -- A description of  the
SISIR certification of businesses as "ODS-Free."

19)   Swedish EPA -- "Eliminating the use of ODSs in Sweden" -- A  discussion
of the programmes sponsored by the Swedish EPA (SNV) to phaseout ODSs in
Sweden.

20)   Toshiba Corporation  -- "Non-ODS Substitutes for Wax Elimination at
Toshiba Corporation" -- A description of the qualification and implementation
of a vinyl-copolymer-type masking agent to replace wax masking in  plating
applications at aircraft maintenance facilities.  Unlike  wax,  the  new masking
agent can be removed without the use of solvents.

21)   U.S. Air Force Aerospace Guidance and Metrology Center -- "Using  New
Technologies to Solve Unique Precision Cleaning Operations:  The Elimination
of Ozone-Depleting Solvents at the Aerospace Guidance and Metrology Center at
Newark Air Force Base"  --  A description of the non-aqueous  alternatives  used
to eliminate the use of ODSs in precision cleaning applications.   Alternatives
                     1994 UNEP SOLVENTS, COATINGS. AND ADHESIVES REPORT *
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addressed include  alcohols,  volatile methyl siloxanes,  supercritical fluids,
and perfluorocarbons.

22)   Vibro-Meter  SA  --  "The implementation of Water-Based  Cleaning at Vib.ro-
Meter SA, Switzerland"  --  A description o'f the implementation of a water-based
cleaning system  to remove  flux residues from printed circuit  assemblies used
in vibration detectors.  Includes a brief evaluation of  other  alternatives
considered.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      •11-3

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             ALLIED SIGNAL -  AN EVALUATION OF AQUEOUS TECHNOLOGIES
I.     INTRODUCTION .

      In response to the Allied Signal corporate mandate to eliminate the use
of all Class I ODSs from its cleaning operations,' Allied Signal Aerospace
Canada (ASAC) chose to develop a saponified aqueous replacement process.  The
project was undertaken in conjunction with recommendations made by the
Electronics Defluxing Alternative Team (EDAT), comprised of scientists and
engineers from various Allied Signal Aerospace divisions throughout the United
States and Canada.
II.   EVALUATING METHODS

      A total quality leadership-style  (TQL) approach was used, whereby a team
of manufacturing engineers representing all facilities were responsible for
the evaluation of various alternatives.  The EDAT classified potential
alternatives into three categories:, those available for immediate
incorporation, those not as readily available and those that would not be
considered.  The team evaluated three cleaning technologies for immediate use:
semi - aqueous, saponified aqueous, and fully aqueous.  EDAT used the Index of
Technical Feasibility as an analytical measure ranking all weighted technical
factors against the relative net present value including life cycle costs to
evaluate each alternative.  The final selections were based on tests performed
on 28 cleaner technology/equipment combinations.  Of these combinations, 8
semi-aqueous, 14 saponified, aqueous and six fully aqueous combinations of
batch and in-line equipment were considered.  The controls were CFC-113 and
methyl chloroform solvent baseline'processes.

      A standard and controlled evaluation protocol was developed for all
phases of testing.  The standard test protocol was based on IPC-CP-61.  The
amount of ionic contamination on 331 test specimens was determined in
accordance with IPC-TM-650, Method 2.3.26.1.  In addition to the commonly used
visual and ionic testing, EDAT evaluated numerous samples using high-
performance liquid chromatography (HPLC), surface insulation resistance (SIR)
and ion chromatography tests.  The SIR  test was performed on 306 of the
standard test specimens in accordance with IPC-TM-650, Method 2.6.3.3, Class
III.  A total of 10,710 SIR readings were taken from seven SIR test patterns
on each board, with five readings per pattern.  The specific 'attributes EDAT
required for the SIR tests included:

      •     the -results should be as good as or better than the baseline
            controls
      •     resistance readings not less than 108 ohms
      •     the difference between initial resistance readings and the first
            readings at temperature and humidity should be less than LOG 3.

      The SIR and HPLC tests were used  to identify residual organic residue.
The ion chromatography test measured residual ionic contamination and
classified them as a chloride, bromide, nitrate or a weak organic acid.
Adhesion testing was carried out with acrylic and urethane coatings on 108 of
the test boards.  Extensive wash and rinse water analyses were conducted and
testing was completed for a minimum number of parameters, including lead, BOD


                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                                     11-4

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 (biological oxygen demand) and pH.  The EDAT also completed cost analyses for
 all of the candidate processes.  The cost analyses considered capital outlay,
 installation costs, and operation and maintenance costs.
 III.   EVALUATION RESULTS

\       The evaluation of the test results was performed in three phases.  Phase
 I included candidates available for immediate use, Phase II involved detailed
 tests using various equipment alternatives and the best chemistries identified
 in Phase I, and Phase III addressed additional chemistries using the equipment
 selected in Phase II. , The SIR data was given the most weight in test
 evaluations primarily because EDAT believed that SIR tests were the most
"realistic indicator of long-term reliability.  Final test results revealed .
 that two aqueous saponifiers .best satisfied the test criteria:  an inorganic -
 based aqueous saponifier with a moderate pH and an organic-based monoethanol-
 amine (MEA)/glycol ether-based aqueous saponifier.  The inorganic-based
 aqueous saponifier performed effectively and had human and environmental
 safety advantages. -These advantages were the primary reasons for its
 implementation at the Commercial Avionics System Division.-  Although the
 inorganic-based aqueous saponifier.is used in a 10% concentration versus a 4%
 concentration for the organic-based cleaner, its extended bath life makes it a
 more economical cleaner.  In addition, the inorganic saponifier is less
 aggressive on solder masks than other saponifiers that have a tendency to
 remove dry-film solder masks.  Finally wastewater analysis confirms that the
 use of inorganic-based saponifiers reduces wastewater contamination,  thereby
 reducing water treatment costs.

       Overall, testing of the aqueous saponifiers reveal that both perform
 better than the benchmark used in the EPA/DoD/IPC Ad Hoc Phase II testing.
 IV.    FOR FURTHER INFORMATION, PLEASE CONTACT:

             Michael Weidman
             Sector Programme Coordinator
             Allied Signal Aerospace
             400 N. Rogers Road
             Olathe, KS 66062-1212
             USA
             Tel:  1-913-768-2294
             Fax:  1-913-791-1341  .
                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                ELIMINATING OZONE-DEPLETING SUBSTANCES AT AT&T
I.     SUMMARY

      AT&T became a corporate leader in the research and development of
alternatives to ozone-depleting solvents.  At AT&T, ODSs were used as solvents
in a variety of processes ranging from metal degreasing to circuit board
fabrication, circuit board assembly, multi-chip module assembly, and
semiconductor manufacture.  This product variety made AT&T's ODS elimination
efforts more difficult than at a less vertically-  integrated company.  AT&T
was able to eliminate ODSs by using its research and development strengths and
manufacturing expertise at Bell Laboratories to develop alternative
technologies.  Also critical to the success of the company's efforts were
factory teaming and management support and commitment.

      Since developing its alternative technologies, AT&T has expended
significant effort sharing its technology with other companies.  AT&T,
Northern Telecom, and U.S. EPA formed with six other founding companies to
support these goals, the International Cooperative for Ozone Layer Protection
(ICOLP).
II.   INTRODUCTION

      AT&T began developing and testing water-soluble fluxes  in the early
1980s with good success.  In 1988, the company astounded the  world when they
organized a press conference with U.S. EPA to announce they had co-developed a
.terpene-based solvent to replace CFC-113 in some processes.   Until then, it
was argued that CFC was essential to electronics manufacturing.  The  following
year, AT&T developed a precision spray fluxer for use with low-solids  (no-
clean) fluxes.  The same year AT&T announced its goals for aggressively
eliminating ODSs as part of a comprehensive pollution prevention plan.

      In 1990, AT&T reaffirmed its commitment to the environment by
eliminating the use of CFCs in its packaging materials.  This and prior
actions led to public recognition, including two awards':  The American's
Corporate Conscience Award from the Council on Economic Priorities, and a U.S.
Environmental Protection Agency (EPA) Stratospheric Ozone Protection  Award.
The following year, additional public recognition for the company's
environmental efforts included the-New Jersey Governor's Award for Outstanding
Achievement in Pollution Prevention, the National Association for
Environmental Management's Environmental Excellence Award, a  citation in the
first President's Environment & Conservation Challenge Award, and another EPA
Stratospheric Ozone Protection Award.  AT&T also completed development of a
water-soluble flux suitable for military applications in 1991.

      AT&T has continued to aggressively research and develop alternatives to
ODS from 1992 to present.  Some of the recent developments include:

      •     a technique for manufacturing integrated circuits using a non-
            ozone-depleting solvent;
      •     a water-soluble solder paste comprised of common  food ingredients;
            and
      •     a low-residue soldering iron technology.


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      AT&T eliminated about 1.1 million kg of CFC emissions from its
manufacturing operations worldwide by year-end 1992. This action resulted in
millions of dollars in manufacturing cost savings.  Also during 1992, AT&T was
awarded its third U.S. EPA Stratospheric Ozone Protection Award and shipped
its 100th low-solids spray fluxer.  In 1993, AT&T announced that it had
virtually eliminated ODS emissions from its manufacturing operations.
III.  ODS ALTERNATIVES

      AT&T investigated many types of options to re'place ODS use, including:

      •     alternative cleaning technologies;
      •     no-clean technologies; and
      •     alternative manufacturing technologies.

      The implementation of all of these options was needed in order to
successfully eliminate its use of ODSs because of the great variety of
applications in which ODSs were used.

Alternative cleaning technologies

      AT&T found that it could change the flux or the solvent used and still
obtain acceptable product quality for many of its processes.  Technologies
implemented included water-soluble fluxes and terpene-based solvents.

Water-soluble flux.  AT&T was one of. the first companies to implement water-
soluble fluxes and aqueous cleaning  processes.  First initiated in 1981, AT&T
continues to use this method in.the  manufacture of some circuit boards.  In
1993, AT&T developed a new family of solder pastes using common U.S. Food and
Drug Administration-approved food ingredients to create a water-washable
solder paste that is more benign and easier to use than previous water-soluble
formulations.

Terpene-based solvents.  AT&T worked with Petroferm, Inc. to develop a solvent
to replace CFC-113.for circuit boards that could not be cleaned with water
alone.  The companies completed development and testing of a cleaning solution
called BIOACT(R)-EC7 in early 1988.  Since this solvent was derived from
oranges, it was biodegradable and could be safely handled by a conventional
sanitary waste treatment facility.

No-clean technologies

      AT&T, working cooperatively with ICOLP and other companies, also
investigated the option of using low-residue, low-solids fluxes to eliminate
the need for post-solder cleaning altogether.

Low-solids spray fluxer.  In 1989, AT&T already had implemented its patented
system in its factories, and thus eliminated the need to clean electronics
circuitry after soldering.  This system'controls the application of low-solids
flux coatings on circuit boards through precision spraying.  As a result,
little post-solder flux residue remains and cleaning is unnecessary.  In 1994,
this technology is being used by AT&T and more than 40 other companies
worldwide.         '               .                •
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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Low-residue hand soldering.  AT&T developed a hand soldering iron that greatly
reduces the residue from cored-solder wire.  It then licensed the technology
to Hexacon Electric Company so that others could use this no-clean technique.

Alternative manufacturing technologies

      AT&T investigated whether certain products could be manufactured using a
different process altogether in order to avoid cleaning methods using ODSs.
The company developed alternative manufacturing methods for two of its
products -- printed circuit boards and integrated circuits.

Printed circuit board fabrication.  During the manufacture of printed circuit
boards, a photoresist technique has been used to develop the pattern of
conductors on the board.  This process originally used chlorinated solvents
but now uses an aqueous solution developed .by AT&T, eliminating usage of
millions of kilogrammes of ozone-depleting and non-ozone-depleting chlorinated
solvents.

Integrated circuit fabrication.  In early 1993, AT&T scientists and engineers
announced that they had developed a new technique for the manufacture of
densely packaged integrated circuits .(multi-chip modules).  The new process
used n-butyl butyrate (a common non-toxic chemical) instead of 1,1,1-
trichloroethane.  N-butyl butyrate is a chemical that occurs naturally in
cantaloupes and other fruits.
IV.  . RESULTS

      AT&T applied each of these technologies as early as feasible to achieve
its ODS elimination goals.  AT&T's ODS emissions had been reduced 86 percent
by year-end 1992, with 100 percent elimination at 20 of 44 majority-owned AT&T
plants.  AT&T had virtually eliminated ODS emissions from all manufacturing by
April 1993.  Not only did this have environmental benefits, but it resulted in
cost savings and yield improvements in many manufacturing processes.


V.    TECHNOLOGY SHARING

      AT&T's technologies to replace ODS use are available for use by
electronics manufacturers worldwide.  In addition to developing unique
alternative technologies, AT&T has participated in a number of industry
cooperatives, several of which have successfully formed partnerships with
government to further the dissemination of information on alternative
technologies.

      To help others address the ODS issue, AT&T founded or participated in
the following initiatives:

      •     ICOLP.  A cross-industry organization, the International
            Cooperative for Ozone Layer Protection (ICOLP) is dedicated to
            sharing knowledge about ODS substitutes with manufacturers
            worldwide, especially in developing countries that lack resources
            to research arid  develop their own alternatives.  ICOLP created
            OZONET, a database of technical options to replace ODSs that is
            accessible from more than 750 cities in 35 countries.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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            GEMI.  The Global  Environmental Management Initiative (GEMI)
            fosters environmental  excellence by businesses worldwide.   It
            coordinates  initiatives  with academia,  government,  and non-
            governmental organizations.

            UNEP.  AT&T  scientists have  participated in the first,  second and
            third Solvents,  Coatings,  and Adhesives Technical Options
            Committees for  the United  Nations Environmental Programme  (UNEP).
            The committees  evaluate  the  alternatives to ODSs for cleaning
            applications and forward recommendations to the signatories to. the
            Montreal Protocol.

            Environmental Management Roundtable.  This forum for senior
            environmental officers of  major U.S.  companies meets regularly to
            transfer technologies  and  information.

            Ad Hoc Solvents  Working  Group.   This  group is  a U.S.  EPA,  U.S.
            Department of Defense, and industry partnership to  qualify ODS
            alternatives for military  applications.   AT&T  chaired the  Testing,
            Monitoring and Validation  Committee.
VI.   FOR FURTHER INFORMATION, PLEASE  CONTACT:

            Dr. Leslie Guth
            AT&T Bell Laboratories
            P.O. Box 900
            Princeton, NJ 08542-0900
            USA
            Tel:  1-609-639-3040
            Fax:  1-609-639-2343

            Tricia Geoghegan
            AT&T Public Relations
            Room B1338 ,
            131 Morristown Rd.              /
            Basking Ridge, NJ 07922
            USA
            Tel:  1-908-204-8264
            Fax:  1-908-204-8549
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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             SEMI-AQUEOUS EQUIPMENT CONVERSION AT BECK ELECTRONICS
I.    SUMMARY

      Beck Electronics manufactures electronic products including professional
telecommunications and avionic systems.  Many of its production  lines  shared a
central CFC-113 cleaning facility.  As a result, Beck engineers  sought a
solvent-type technology which would minimize disruption of production.  After
evaluating many types of technologies, Beck decided on terpene-based solvents
in conjunction with water rinsing.  Since terpene-type degreasers were not yet
commercially available, Beck retrofitted two vapour degreasers to use  terpene-
based solvents.
II.   INTRODUCTION

      Beck's product line includes Electro-Magnetic  Interference  (EMI)  filters
for use in Electro-Magnetic Compatibility (EMC) applications, whose  typical
end uses include telecommunications and avionic systems.  Since the  central
CFC-113 degreasing facility serviced over 1,500 different types of products,
Beck preferred to find a technology as close as possible in operation to CFC-
using cleaning equipment in order not to interfere with the many  manufacturing
processes dependent on solvent cleaning.  "No-clean"  technologies were  ruled
out.

      The general-purpose nature of the facility also meant that  the new
solvent had to be compatible with the polymer resins  and lacquers used  in  some
products, yet aggressive enough to clean even "baked-on" flux residues.  Beck
also strove to avoid any new process that would have  a significant
environmental impact, "such as technologies resulting, in the generation  of
wastewater.

      Beck's first step was to test twenty different  alternative  solvents.
Those solvents formulated around citrus- or pine-derived terpenes had the  best
results in terms of both compatibility and effectiveness.  Unfortunately,
equipment specifically built for these solvents was not commercially available
at the time.

      Time was critical due to the impending deadline set by the  Montreal
Protocol.  Beck's solution to this dilemma was to build its own equipment  by
converting old vapour degreasers already in its possession.
III.  DESIGN CRITERIA

      Beck chose to use terpene-based solvents with a water rinse because  of
the large amounts of soil to be removed and the need to remove  ionic
contamination.  However, since terpenes are insoluble in water,  the first
stage of rinsing required emulsification of the solvent to allow rinsing by
successive water stages. . Ultrasonic agitation assisted in forming the
emulsion.  Beck also found that the terpene-based solvents were most  effective
when heated to about 40° C, and that overheating would lead to  early
deterioration of the solvent and would pose a fire hazard.  To  avoid  the
generation of wastewater, Beck also required a method to separate the emulsion


               '   -  * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-10

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so that the soil and spent solvent could be isolated for removal and disposal
or recycling.
IV.   PRACTICAL SOLUTION

      Beck had two older two-stage vapour degreasers, one of which had an
ultrasonic compartment that was ideal for the emulsification process.
However, simply filling the other (sump) side with the terpene-based solvent
was not practical because direct heating meant that the solvent in contact
with the heating element would become too hot.  Beck decided to try an
indirect heating approach.                          «

      To heat the solvent, A stainless steel tank purchased from a local
catering equipment store was suspended in the sump, which also contains
emulsified solvent.  A pump was connected between the sump and the ultrasonic
side of the degreaser so that the hot emulsion could be circulated over the •
weir between them.  In this way, the sump containing the solvent was heated by
contact with the emulsion.

      A stainless steel solvent tank, purchased from a local catering
equipment store was suspended in the sump, which also contains emulsified
solvent.  A pump was connected between the sump and the ultrasonic side of the
degreaser 'so that the hot emulsion could be circulated over the weir between
them.  In this way, the solvent in the new stainless steel tank was heated by
contact with the emulsion.                                             •

      The second vapour degreaser was used to perform the final water rinses.
Initially, tap water was used.  However, Beck soon converted to deionized
water to control ionic contamination.  The deionized (DI) water is circulated
through a carbon filter and resin filter.  A later refinement was to circulate
the solvent and emulsion through particulate filters to prolong their
usefulness.
V.    PROJECT SUMMARY

      •     Solvent:  Terpene-based.

      •     Solvent compartment:  Inner compartment suspended  in
            existing sump tank of vapour degreaser.   Indirectly heated
            to about 35° C.  Circulated through particle  filter.

      •     Emulsion compartment:  Directly heated to about 40° C using
            existing heaters.  Ultrasonic capability  of vapour degreaser
            aids in emulsification.  Emulsion circulated  over  weir,
            around solvent  tank, and returned through particle filter.

      •     Rinsing method:  Deionized (DI) water at  ambient
            temperature.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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VI.   FOR FURTHER INFORMATION, PLEASE CONTACT:

            M.  A.  Hazell
            Beck Electronics Limited
            Main Cross Road South Denes
            Gt  Yarmouth Norfolk
            United Kingdom NR30 3PX
            Tel:   44-493-856282 or 330332
            Fax:   44-493-850169 or 859025
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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    CFC SOLVENT ELIMINATION  IN ELECTRONICS  SOLDERING AT  FORD MOTOR COMPANY
I.    INTRODUCTION

      The strategy to eliminate chlorofluorocarbon  (CFC)  solvent  cleaning  from
Ford Motor Company's electronics printed circuit-board manufacturing processes
was based on the international recognition of CFC environmental concerns.  The
successful implementation of CFC-free soldering technologies was  the result of,
developing and applying innovative manufacturing processes.  Ford Motor
Company became a leader in  inert gas wave soldering and eliminated CFC
cleaning processes ahead of the schedule mandated by the  Montreal Protocol.
With the cooperation of the United States Environmental Protection Agency  and
members of the International Cooperative for Ozone Layer  Protection, worldwide
technology sharing was accomplished to expedite the CFC/ozone depleting
solvent elimination program.  This case study will,highlight the  technical,
environmental, and managerial success Ford achieved as a  result of
accelerating the implementation of .the Montreal Protocol.

                                         /
II.   CLEANING OPTIONS

      The first steps taken to eliminate CFC/ozone depleting solvent cleaning
were to research potential  technologies, develop the most viable  options,  and
test these alternatives for reduction/elimination potential.  The
possibilities were numerous, with each technology providing advantages rnd
disadvantages.  The field was narrowed to five possible solutions:.  No Clean
Flux, Inert Nitrogen Soldering, Aqueous Cleaning, Semi-Aqueous Cleaning, and
Hydrochlorofluorocarbon Solvent Cleaning.  A study was conducted  to identify
key elements of each technology for feasibility to existing Ford  manufacturing
plants worldwide.  This study highlighted each technology for its
effectiveness in eliminating CFC solvent cleaning.  Some  key areas considered
were printed circuit board  cleanliness, product reliability, equipment
reliability, environmental  impact, and cost competitiveness.  The selection
was narrowed to two technologies that rated highest in these categories:   No
Clean Flux and Inert Nitrogen Soldering.  The implementation of these two
technologies provided the best solution for CFC/ozone depleting solvent
elimination, but required significant development and testing.

      The following list highlights the advantages and disadvantages each
technology presented for worldwide implementation:

      No Clean Fluxes
      Pros:
            Uses existing solder systems
            Lowest cost
            Eliminates CFC emissions
            Reduces volatile organic compound emissions
            Eliminates cleaning machines
            Shortest implementation lead time
            Reduces' material usage
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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       Cons:

       •      Requires new application/control equipment
       •      Need to determine solder quality
       •      Need to determine probe test capability
       •      Need to determine conformal coat compatibility
       •      Need to determine product long term reliability
       •      Need to determine component solderability

       Inert  Nitrogen Soldering

       Pros:

       •      Flux with low solids used                 ' •
       •      Best printed circuit board cleanliness
       •      Probe test easily
       •      Conformal coats easily
       •      Eliminates CFC emissions
       •      Reduces volatile organic compound emissions               «
       •      Eliminates cleaning machines
       •      Reasonable implementation lead time
       •      Improves product quality
       •      Reduces material usage - - flux and solder
       •      Requires less floor space

       Cons:

       •      Additional costs for cryogenic nitrogen and equipment
       •      Replace existing solder equipment
       •      New handling procedures for chemicals
       •      Need to determine equipment emissions
       •      Need to determine product long term reliability
       •      Need to determine component solderability
       •      Need to determine.solder quality

       With the completion of extensive field, laboratory,  and manufacturing
 plant testing, the new process merged both technologies with superior results.
 Solder quality was enhanced with cooperation of component suppliers providing
 improved solderable components to meet the new requirements of the lower
 activity fluxes used for inert nitrogen soldering.  Flux formulations were
 developed using low activity organic acid without rosins or resins added.
 Product  long term reliability was proven in fleet vehicles and extensive
'laboratory life tests with 100 percent compliance.  Equipment emissions were
 eliminated for CFCs (100 percent),  and formic acid (100 percent),  and reduced
 for volatile organic compounds (70 percent) and lead (40 percent).   Printed
 circuit  board probe testing without cleaning was tested and implemented.
 Conformal coatings without volatile organic compound content were developed
 with suppliers to eliminate process emissions.  CFC cleaning machines were
 removed  from the production floor,  which resulted in extra floorspace.  Flux
 material usage was reduced to 80 percent with flux-thinner purchases
 completely eliminated.  Flux density test/control equipment was removed from
 the process  with new spray technology and handling procedures.  End-of-line
 ionic contamination equipment was removed from the process with new cleaner
 solder process stability.  New inert wave solder equipment innovations were


                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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developed with suppliers to reduce solder joint defects to less than  10 ppm.
Finally, capital equipment expenditures were recovered and resulted in
additional long term savings in materials consumption, quality products, and
equipment reliability.
III.  BENEFITS

      The elimination of all CFC cleaning on May 1, 1993, for Ford Electronics
facilities, exceeded the timing of the Montreal Protocol.   In addition  to
realizing the benefits of CFC emission elimination programs, Ford Electronics
embarked on a policy of waste minimization for all sources.  This internal
requirement to minimize emissions to the fullest extent technically possible
resulted in lower emissions in areas not covered by the Montreal Protocol.
Volatile organic compound reductions resulted from new equipment developments,
material developments, and process parameters that reduce solvent emissions at
the source.  The ultrasonic fluxer technology eliminated the need to use
containment equipment to capture flux volatiles.  The 100 percent solids
conformal coatings eliminated the emissions of solvents during cure time.  The
use of inert gas in soldering reduced the content of lead .oxides being  formed
as waste in emissions.  Finally, process enhancements eliminated the use of
formic acids in the solder process.
•IV.   CONCLUSION

      Ford has shared the knowledge gained from its successful program.
Ford's involvement with  the International Cooperative for Ozone Layer
Protection has resulted  in supporting and presenting technical papers at
international conferences.  This commitment  increases the technical knowledge
of the electronics industry in CFC elimination strategies.  Ford has supported
government/industry publications that benchmarked prior cleaning effectiveness
and set the path for emerging replacement technologies.  This global
responsibility, with the help of the United  States Environmental Protection
Agency, has produced outstanding results and achievements for Ford Motor
Company and others.                                  .   '

      The success of this program was highlighted by awards presented to
Ford's electronics operations and its employees from various sources.  The
United States Environmental Protection Agency and the International
Cooperative for Ozone Layer Protection recognized Ford's contributions, as did
the State of Pennsylvania.  Various employees have won awards from Ford for
their contributions.
V.    FOR FURTHER INFORMATION, PLEASE CONTACT:

            Jay Baker
            Ford Electronics Technical  Center
            Room C130
            17000 Rotunda Drive
            Dearborn, MI 48121
            USA
            Tel: -1-313-845-3597
   •     .    Fax:  1-313-323-.8295
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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Peter J.  Sinkunas
Ford Electronics Technical  Center
Room C130
17000 Rotunda Drive
Dearborn,  Ml 48121
USA
Tel:  1-313-845-^643
Fax:  1-313-323-8295
        * 1994 UNEP SOLVENTS. COATINGS, AND ADHES1VES REPORT *
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       REDUCTION AND ELIMINATION OF OZONE-DEPLETING SOLVENTS AT HITACHI
I.    INTRODUCTION

      Industries in Japan were requested to switch the usage of
trichloroethylene and tetrachloroethylene to 1,1,l-trichl(oroethane in the  late
1980s.  Hitachi adopted this policy and changed its systems to 1,1,1-
trichloroethane in 1989.  Hitachi began to reduce usage of CFC-113 iti 1988 by
introducing recovery and recycling systems.  The company has been steadily
reducing its consumption of ozone-depleting solvents•since 1989,  Hitachi
completed its phaseout of CFC-113 in 1993, and 1,1,1-trichloroethane will be
phased out in 1994. '

      The company became a member of the International Cooperative for Ozone
Layer Protection (ICOLP) to support this belief.  It also sent experts to many
ODS phaseout strategy meetings and seminars, with a special focus on those
held in developing countries.

      Hitachi produces several kinds of products, including electric power
generators, electricity transmitting equipment, computers and peripherals,
communication equipment, trains, semiconductor devices, and domestic
appliances.  Alternative cleaning technologies considered to replace ODS
solvents for each of these products are described in this case study;
II.   ALTERNATIVE TECHNOLOGIES

      Hitachi was accustomed to using solvents in cleaning applications and
initially focused on solvent-type alternatives, including:

      •     Hydrochlorofluorocarbons (HCFCs);                            '
      •     Perfluorocarbons;                                         .
      •     Alcohols;
      •   .  Aliphatic Hydrocarbons
      •     Ketones;
      • .    Ethers; and                                         ,
      ?     Aromatic Hydrocarbons.

      CFC-113 and 1,1,1-trichloroethane are very effective solvents for which
Hitachi found no equivalent solvent-type replacements to meet its cleanliness
and material compatibility needs.  HCFC-225 was initially considered by
Hitachi to be similar enough to ODS solvents be a drop-in replacement.
However, the Montreal Protocol was amended in 1992 to include the phaseout of
HCFCs by the end of 2030, so Hitachi considered this chemical a temporary
solution at best and did not actively pursue its use.

      Subsequently, many types, of non-solvent cleaning and no-clean
substitutes were investigated in an attempt  to match the cleaning ability of
the ODS solvents.  Hitachi considered the available alternatives including:

      •     No-clean technologies, e.g., evaporating oil, lubricant coated
            steel sheets, thin polymer peeling sheets,, and ultrasonic plastic
            deformation;           '    .   '
      •     Mechanical cleaning, e.g., blasting and pressurized gas;


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      •     Aqueous cleaning, e.g., alkaline cleaners, hydrocarbon/surfactant
            cleaners, and steam distillation under vacuum; and
      •     Miscellaneous options, e.g., ultraviolet  light/ozone cleaning,
            supercritical cleaning.

      Based on its investigation, Hitachi established internal guidelines for
the selection of alternative chemicals and technologies.  These guidelines
are:

      •     No-clean technologies are recommended.
      •     Chlorinated solvents are generally prohibited,' including HCFCs.
            However, HCFC-225 may be appropriate at times, but only for
            transitional use.
      •     Low-boiling point PFCs are restricted.
      •     Energy consumption of alternative technology  is a prime
            consideration.

      The remainder of this case study presents some  of the options considered
which were eventually adopted by Hitachi.

No-Clean Technologies

      Hitachi considered the following no-clean alternatives to reduce its use
of ODS solvents:

      •     lubricant coated steel sheets;
      •     drying press oil; and
      •     ultrasonic plastic deformation in pipe working.

      The use of lubricant-coated steel sheets was one of the no-clean options
considered.  In conventional metal pressing applications, lubricating oil is
applied and the oil is cleaned off after-working the metal.  The drawing
characteristics of lubricant-coated steel sheets are  the  same as non-coated
steel sheets.                                 .         •

      Drying press oil was a second no-clean alternative  evaluated.
Conventional lubricating oil for punch working is not volatile and the oil
must be cleaned off after working the metal.  Recently, volatile lubrication
oil has been developed which generally leaves minimal residual oil film
thicknesses after only one hour drying time at room temperature.  Film
thicknesses can be reduced even faster at higher temperatures, but a drying
furnace is recommended for the fastest drying.  It is important to note that
some of these drying oils contain chlorinated solvents and require that
special attention be paid to occupational health and  safety.

      Ultrasonic plastic deformation in pipe working was  the final no-clean
option considered.  When ultrasonics are used in plastic  deformation
processes, it is known that changes occur, including:
                     %
      •     reduction of deformation resistance
      •     reduction of friction between tool and work piece
   •   •     physical and mechanical property changes  in metal
      •     temperature increase in metal.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-18

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      Since the deformation resistance and friction between  tool  and work  can
be reduced, some pipe working can be accomplished without  lubricating  oil.   In
the case where the thickness of the pipe wall  is not  large,  the pipe wall  will
be bent or expanded without lubricating oil

Blasting technology                              •

      Some types of residue can be cleaned from work  pieces  by blasting  solid
particles at the work surface.  When flammable solid  particles are used,
careful attention must be paid to avoid combustion.

Aqueous cleaning and wastewater treatment

      In aqueous cleaning at Hitachi, typically, work pieces are  cleaned in
the first stage, removed and subjected to two rinse stages,  and then dried.
It is important to monitor the concentration of cleaning agents which  are
dragged from the cleaning tank to the rinse tanks since the  cleanliness  of the
work piece depends on the purity of the final rinse water.

      Each type of cleaning agent may require a different -type of wastewater
treatment for the effluent generated.  It is very important  to investigate the
types and amounts of materials that may be dissolved  in the  wastewater since
some aqueous cleaning agents remove larger amounts of metals, e.g. lead, than
CFC-113 or 1,1,1-trichloroethane.                                      .

Ultraviolet light/ozone cleaning

      By applying large doses of ultraviolet light to the  surface to be
cleaned, ozone is created from the surrounding atmosphere.   Ozone is a very
reactive substance and oxidizes organic compounds to  create  carbon oxides and
hydrogen oxides.  These products are volatile and evaporate  from  the surface
of the part being cleaned.

      This type of cleaning technology is effective in removing organic
residues from the surface of the part, but is  ineffective  on non-organic
residue since the oxides formed are nonvolatile and remain on the surface of
the part.


III.  FOR'FURTHER INFORMATION CONTACT, PLEASE CONTACT:

            Mr. Yoshiyuki Ishii  .
            Senior Engineer
            Environment Policy Office                      ,    :
            Hitachi, Ltd.
            New Marunouchi Building  .
            5-1, Marunouchi 1-chome, Chiyoda-ku
            Tokyo 100
            Japan
            Tel:  81-3-3212-1111 x2722
            Fax:  81-3-3214-3545
                    * 1994 UNEP SOLVENTS. COATINGS, AND^ADHESIVES REPORT *
                                     11-19

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            REPLACEMENT OF OZONE-DEPLETING SUBSTANCES IN HONEYWELL
                      SPACE AND AVIATION CONTROL PRODUCTS
I.    INTRODUCTION                        '

      This case study focuses on the alternatives examined  for  implementation
in Space and Aviation Control products.   Honeywell  Space and Aviation  Control
offers:  systems integration capabilities, automatic flight control  systems,
electronic cockpit displays, flight management systems, precision  components
for strategic missiles, and other control technology for space  and aviation
applications.  The combined usage of CFC-113 and 1,1,1-trichloroethane  in  1988
for these facilities was approx. 590,000 kg.
II.   PRINTED WIRING BOARD CLEANING

      Space and Aviation Control assembles plated  through-hole boards, mixed
technology boards, and surface mount-only boards.  The primary solvent used
for cleaning in this application is Freon-TMS, an  azeotrope  of CFC-113 with
methanol.  The primary challenge for cleaning  is in  surface  mount  technology
applications, which have tight clearances to the board and a high  packing
density of components on the board.  A test board  was designed with  surface
mount technology  and a range of components from 50 mil to 20 mil pitch.
Cleanliness was determined using surface insulation  resistance testing,
ionograph testing, and residual rosin testing.  Material compatibility tests
were also performed on the various materials found in the assembly of printed
wiring boards.

      Semi-aqueous solvents.were selected as an interim step for the
replacement of CFC-113 and 1,1,1-trichloroethane because of  the high
reliability and performance requirements of space  and aviation products and
because of the time-frame required for substitution.  The implementation of
semi-aqueous solvents required .only a change in the  cleaning material and no
change of the flux since the semi-aqueous solvents were formulated to remove
the traditional rosin residue.  Six semi-aqueous solvents were tested and two
were selected for implementation -- a terpene  hydrocarbon and an aliphatic
hydrocarbon.  In-line and batch equipment purchased  and installed  in 1993
worked extremely well at the facilities.  For  .example, a Minneapolis facility
realized a US$400,000 savings in raw material  costs  in a single year because
of the implementation of these alternative solvents.  The semi-aqueous
technology implemented also proved to be a viable  alternative for  high-
reliability applications.
III.  GYROSCOPES AND PRECISION GUIDANCE INSTRUMENTS

      Momentum control gyroscopes and precision guidance  instruments  are used
to control and detect movement in satellites, space probes and platforms,  and
missiles.  Contamination-free- surfaces are required during fabrication  in
order for these devices to operate reliably for extended  periods  of time in
harsh military and space environments.  The cleaning processes used must be
compatible with a variety of materials, including:  metals,  thermoset
polymers, thermoplastics, elastomers, lubricants, -organic and inorganic
coatings, and optical components.  In addition, cleaning  processes must be


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-20

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effective in removing contaminants  such as hydrocarbon,  ester,  and
fluorocarbon lubricants, handling debris, damping  fluids,  and process
residuals.

      For particle removal  in critical cleaning  operations,  C02  "Snow",
perfluorocarbon sprays, and water-based sprays were  selected as  alternatives
to ozone-depleting solvents.  Equipment has also been  specially  designed  to
use perfluorocarbon solvents for the removal of  fluorocarbon oils  and  greases,
while limiting solvent emissions to the atmosphere.  Carbon  dioxide  is also
being used in another cleaning process -- supercritical  fluid cleaning --  for
the removal of a wide variety of oils.  Flammable  and  combustible  solvents
have also been employed for processes that are not compatible with other
alternative cleaning solutions.
IV.   CONCLUSIONS

      The varied nature of the substrates being cleaned and  the  contaminants
present, coupled with the required high reliability of military  and  space
hardware, led to the. development and  implementation of a wide variety  of
cleaning processes and materials that use no ozone-depleting substances.
Figure XI-1 shows the annual use of CFC-113 and 1,1,1-trichloroethane  at the
Honeywell Space and Aviation Control Operations.  In  1988  the combined usage
of these ozone-depleting solvents was 590,000 kg.  By the  end of 1993, the
usage had decreased by 73% to 160,000 kg and the company saved millions of
dollars in raw material costs.  Many of the alternative processes  implemented
are new, while others like aqueous cleaning were already in  use  in cleaning
applications but''required further development and refinement for use on high-
re.liability hardware.  The result of  implementing alternative cleaning
techniques for Honeywell Space and Aviation Control products was not less
dependable equipment, but rather higher quality hardware whose cleaning
processes have been thoroughly evaluated and qualified.
V.    FOR FURTHER INFORMATION, PLEASE CONTACT:

            Mr. Lee Tischler
            Corporate Environment, Health ft Safety
            Honeywell Inc.
            Honeywell Plaza
            P.O. Box 524
            Minneapolis, MN 55440-0524
            USA
            Tel:  1-612-951-2517
            Fax:  1-612-951-2525
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-21

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                   FigureXI-1

      ANNUAL USE OF CFC-113 AND 1,1,1-
TRICHLOROETHANE AT HONEYWELL SPACE AND
       AVIATION CONTROL OPERATIONS
                        73% decrease 1988-1993
         1988  1989   1990   1991   1992   1993
          * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                     11-22

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                     QDS ELIMINATION AT IBM AUSTIN, TEXAS
I.    SUMMARY
      IBM was among the first companies to assess alternative cleaning
technologies in order to take a proactive stance on the CFC Phaseout.  After
ruling out several options for its pilot project, the company successfully
implemented aqueous cleaning.  However, after no-clean technologies were
further developed, the company adapted new, superior alternative.
II.   INTRODUCTION

      ,IBM Austin began a program to eliminate chlorofluorocarbons (CFCs) and
1,1,1-trichloroethane (TCA) from its manufacturing processes prior to the U.S.
ratification of the Montreal Protocol.  In 1987, IBM set goals to drastically
reduce CFCs by 1991 and TCA by 1992.  IBM finalized the company goals in 1990,
setting the date for completion of CFC phaseout at 1993 and TCA phaseout at
1995.

      IBM Austin concluded in 1987 that options that could be implemented
immediately included HCFCs, semi-aqueous cleaning, and aqueous cleaning.
HCFCs were viewed by IBM to be a short-term solution.  No-clean technology was
available but had been neither fully developed nor tested to meet IBM Austin's
rigorous manufacturing requirements.  Semi-aqueous technology, a new
development at the time, required sophisticated fire protection systems to
protect against flammability risks.   Therefore, aqueous cleaning was chosen
in 1987 as the best available solution to eliminate CFC and TCA usage.
Aqueous cleaning would be only ah interim solution until a no-clean technology
that met IBM's manufacturing requirements was fully developed and qualified.

      IBM Austin met its goals and completed the elimination of the use of
CFCs during the first half of 1991 and the use of TCA by year-end 1992.  Over
one year after implementation of water-soluble materials, no-clean had become
the least expensive of all non-ODS cleaning options, reinforcing IBM's
original long-term goal to move to this technology.

      The no-clean process reduces cost in several ways.  First, it eliminates
the cleaning stream as well as the waste stream.  Other important cost-
reducing elements are the elimination of floor space requirements for cleaning
apparatus and the reduction in overall cycle time.  With the elimination of
cleaning operations, the number of required operators on the manufacturing
floor can be reduced.  The low cost of this option, in conjunction with recent
progress made in developing advanced flux materials and the understanding of
the remaining residues has made no-clean a viable alternative.


III.  THE AQUEOUS CLEANING PROCESS

      IBM examine several important elements in implementing the aqueous
cleaning process.  These included:
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-23

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      •     equipment design;     .
      •     process parameter setup; and
      •     process control.

      The cleaner selected was tailored to the needs of IBM's cleaning process
and the type of flux selected.  When specifying the materials of construction,
IBM had to consider the flux activity and the corrosive nature of  the
residues.

      Due to their low vaporization temperatures, typical solvents generally
are dried with forced air only.  Water, on the other hand, does not evaporate
as easily and the design of the drying system for the aqueous cleaning system
required a combination o,f forced air and heat.  The introduction of high-
velocity/high-volume blowers greatly improved the drying of many designs, but
this method was not considered adequate for connectors with openings
perpendicular to the air flow.  Therefore, IBM selected a system with an
optimal heating profile to ensure success.

      Process parameter setup was critical to the successful implementation of
aqueous systems.  Therefore, in order to select an overall set of process
parameters, IBM established a procedure was established to identify and
evaluate the process interactions.

      Process control was another key element in the implementation of aqueous
cleaning processes.  Process control is the ability to produce a product with
consistent quality in mass production.  Good controls ensure that the product
is properly cleaned and that no corrosive residues are present that would have
an adverse effect on the reliability of the final product.  Methods for the
measurement and control of the cleaning process included:

      •    . equipment controls/statistical process control (SPC); and
      •     random temperature,, humidity, and bias stress testing.

      Random temperature, humidity and bias stress testing stimulates the
durability and reliability of a product in the field.
IV.   THE NO-CLEAN PROCESS

      Implementation of no-clean technologies differed significantly from
implementation of aqueous cleaning technologies.  The elements of a program to
implement no-clean materials included:

      •      probe testing/residue thickness;
      »      flux interactions/reliability;
      •      solderability on a copper surface;
      •      ease of manufacturing; and
      •      use of nitrogen as a controlled atmosphere.

      Probe testing was the chief method used to detect assembly-process and
electrical defects on printed circuit boards.  Some no-clean fluxes leave non-
corrosive residues on assemblies which inhibit this form of testing.   In order
to minimize this impact, no-clean methods had to be compatible with probe
testing by leaving little to no residue on the probe surface.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-24

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      Flux interaction with materials  of  construction was  another  critical
factor.  In all cases, whenever  a new  flux  is  to be  implemented, compatibility
with existing materials must be  established.   Although  a rigorous  chemical
composition analysis also might  have been effective, this  was  accomplished
through reliability testing at IBM.

      Initially, it was expected that  solderability  of  the components  and the
carrier would pose a problem to  the implementation of a no-clean process.   It
was thought that hot air solder  level  (HASL) cards would be  required.  Due  to
the added cost of solder levelling and the  adverse effects on  fine pitch
processing, it was decided that  any no-clean implementation  would  use  bare
copper boards with an organic protective  coating.

      The ease of manufacturing  using  solder pastes  and fluxes was another
prerequisite. . IBM's minimum requirement  for no-clean solder pastes was the
ability to screen 0.41 mil pitch components.   In fact,  the robustness  of the
screen printing process was greatly improved as a result of  switching  to no-
clean materials.  Because flux chemistry  turned out  to  be  much more resistant
to.changes.in the temperature and especially the humidity, resulting in better
rheological performance.                                  .

      Another important consideration  during the implementation of no-clean
processes was the use of inert gas.  Nitrogen  is used to control oxidation on
bare copper surfaces, but its use added to  the overall  cost  of soldering.  The
company's ultimate goal was to use nitrogen only over the  wave solder  pot,
where .dross reduction/elimination would provide an additional benefit.

      Solder balls have long been considered a problem  with  the use of no-
clean materials in that the solder balls  are no longer  removed during  a .
subsequent cleaning process.  The formation of solder balls  attached to
discrete chip components was a problem in one  of IBM's  processes.  An  analysis
suggested that the pad size and  dimensions  contributed  significantly to the
problem.  These problems where solved  through  a combination  of design  and
processing controls.

      From 1989 to 1993, IBM Austin eliminated the use  of  CFCs and TCA, and-.
reduced water consumption through the  implementation of no-clean technology
processes:

            approx. 196,000 kg of CFC-113 phased out from  peak 1988
            usage
      •     approx. 140,000 kg of TCA  phased out from peak 1988 usage
      •     Nearly .378.5 litres  per minute  water use eliminated.
V.    FOR FURTHER INFORMATION, PLEASE CONTACT:

  /          John J. Prusak
            IBM Corporation
            11400 Burnet 'Road
            Austin, TX 78758
            USA
            Tel:  1-512-838-6895
        :    Fax:  1-512-838-6953
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-25

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                 THE JAPAN INDUSTRIAL CONFERENCE ON CLEANING
I.    SUMMARY

      In response to the Montreal Protocol, the government of Japan enacted
legislation phasing out the use of ozone-depleting substances, including the
solvents 1,1,1-trichloroethane and CFC-113.  However, users of these chemicals
required assistance, in implementing alternatives to these solvents because of
the great diversity in applications, enterprises, and substitute chemicals and
technologies.  To provide this assistance, a new organization -- the Japan
Industrial Conference on Cleaning (JICC)  -- was formed.  JICC will accomplish
its mission through promoting mutual friendship and cooperation between
members, disseminating and exchanging information, standardizing technologies,
and providing a central point of contact with regulatory authorities.
II.   INTRODUCTION                                        '

      1,1,1-Trichloroethane and CFC-113 are scheduled to be phased out by the
end of 1995 in developed countries.  Total elimination of these substances
entails developing and testing the most appropriate alternative chemicals or
technologies for each application.  To accomplish this task, each of the
.issues listed below must be considered:

      1.     Diversity of application

            Solvent applications are diversified, involving cleaning many
          .different types of'contaminants from a wide variety of parts.  In
            addition, some.applications involve additional processes before
            and after cleaning.  Hence, the individual requirements of each
            process 'must be considered in order to select the most appropriate
            alternative.

      2.     Diversity of enterprises

            Many different sizes of manufacturers have been using ozone-
            depleting solvents, with medium and small enterprises accounting
            for more than 50 percent of total consumption in Japan.  As a
            result of these circumstances, it is important to ensure good
            contact between users of solvents and manufacturers of alternative
            technologies.

      3.     Diversity of alternatives and substitutes

            An investigation of the wide array of alternatives and related
            technologies is essential to selecting the best option' for each
            application.  In addition, users should conduct comprehensive
            testing to ensure the success of the new chemical or technology.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-26

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III.  ESTABLISHMENT OF A NEW INDUSTRIAL ORGANIZATION

      The Japan Industrial Conference on Cleaning was established in April 13,
1994\to assist in phasing out ODS solvents.  Members of JICC are enterprises
involved in supplying equipment and chemicals for various cleaning
technologies, including ultrasonic cleaning, spray cleaning, vacuum cleaning,
and high-pressure cleaning.
IV. "  JICC OBJECTIVES                                              .

      JICC furthers the development of non-ODS cleaning technologies,
contribute to environmental protection, and promote the expansion ,of business
in related fields by working toward a number of objectives.

Mutual friendship and information exchange between members, especially in
different industrial fields.  JICC aims to aid in the exchange of information
to support business activities not only for suppliers of cleaning
technologies, but also for users of such technologies.

Dissemination of information on cleaning technologies through educational
materials and outreach efforts.  JICC facilitates the understanding of new
cleaning technologies.  Educational materials will stress a "total system"
approach, focusing on the strong interdependencies between each segment of
industrial processes and the cleaning process.

Mutual cooperation to further the development of new technologies.  In
particular, JICC will increase and enhance cooperation between different
fields of technologies.

Standardization of related technologies in order to ease the decision process
faced by owners of existing cleaning equipment.  Equipment owners are now
faced with a wide array of options in considering their conversion to
alternative technologies and are in need of some way to reduce their
selections to the best technology for their application.  To meet each user's
requirements, JICC intends to investigate which features can be standardized
on each technology, such as safe'ty and environmental protection features to
meet legal requirements.      •               :

Contact with administrative authorities to deal with special issues which
would be difficult to handle by independent associations.  JICC ,will be become
industry's central point of contact with administrative authorities in the
government and to effectively voice industry's concerns in preparation for'
legislation on present and future global environmental issues.
V.    JICC MEMBERS                                            .  .

      JICC is comprised of four types of members.  Regular members are
enterprises which manufacture cleaning equipment, cleaning agents, and
auxiliary equipment.  Supporting members are enterprises t;hat support JICC's
activities and assist in achieving JICC's objectives.  Group members are
groups that support JICC's activities and assist  in achieving JICC's
objectives.  Finally, special members are groups  that  support JICC's
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                    . 11-27

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activities and assist  in achieving JICC's objectives and are  also endorsed by
JICC's board of directors.
VI.   FOR FURTHER  INFORMATION,  PLEASE CONTACT:

            Secretariat  of JI-3C
            c/o The Japan Society of Industrial
            Machinery Manufacturers (JSIM)
            Kikaishinko  Building, 4F
            3-5-8, Shiba-Koen,  Minato-Ku
            Tokyo, 105
            Japan
            Tel:   81-3-3431-6517
            Fax:   81-3-3431-6518
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      11-28

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       THE ELIMINATION OF 1,1,1-TRICHLOROETHANE IN ELECTRONICS CLEANING
                          AT LOCKHEED SANDERS COMPANY
I.    INTRODUCTION

      An important part of the manufacturing process for printed circuit
boards and other electronic components is the removal of residues during the
post-assembly cleaning process.  In recent years, the Lockheed Sanders Company
used 1,1,1-trichloroethane (TCA) for cleaning electronic components.  However,
in an effort to protect the environment and reduce operating costs, Sanders is
eliminating the use of TCA from its cleaning operations.  This effort has been
implemented through a Sanders Process Action Team.
II.   PROCESS DESCRIPTION
                                    /
      The two standard processes for electronic component cleaning at Sanders
were vapour degreasing and immersion cleaning with TCA.  Due to concern for
ozone layer protection and rising costs associated with TGA-based cleaning as
the production phaseout date approaches, Sanders tested several alternative
cleaning processes.  Sanders chose two spray cleaning systems to replace TCA
for cleaning in surface mount technology (SMT) applications.

Stencil Cleaning

      Sanders selected the EMC Global Technologies Model IPA-30 batch cleaner
for stencil cleaning.  The batch cleaner is a closed-loop, explosion proof
machine incorporating a wash and a dry cycle.  Figure XI-2 shows a simplified
version of the stencil cleaning process.  Isopropyl alcohol (IPA) is sprayed
onto circuit boards via rotating spray arms at high-volume and low-pressure
during the wash cycle.  Excess alcohol evaporates in the dry cycle when air is
pumped through the rotating arms.                     .

Printed Circuit Board (PCB)

      A Hollis/Electrovert HS-332 cleaning machine with Alpha 3555 saponifier
is now used to clean assembled SMT circuit cards.  The cleaning solution is a
concentrated alkaline liquid designed to remove flux residues from soldered
electronic assemblies.  Its characteristic low foaming and high surface
insulation resistance (SIR) satisfy the performance requirements of the
cleaning process.  Figure XI-3 details the cleaning process flow for the
circuit card cleaning system.  In the wash cycle the cleaning solution is
heated and sprayed onto the circuit cards with high volume, high pressure jet
nozzles.  A recirculating pump returns the solution to a holding reservoir for
reuse.  Once the PCBs  have been washed with the cleaning solution they are
spray rinsed with deionized water to remove excess cleaner and residues.  The
parts are dried using "air knives" to remove all moisture that may be trapped
in crevices and are passed through a convection heating station to ensure that
all parts are completely dry.  Finally, the cleaning solution is transferred
to an external ultrafiltration unit where it is recycled and stored for the
next cleaning cycle.  However, due to the build up of dissolved metals and
gradual degradation of the saponifier over time, the cleaning solution must be
changed periodically.  Rinsewaters are being treated using activated carbon
and ion exchange resin beds to form a "closed-loop" rinsewater system.
                     1

                    * 1994 UNEP SOLVENTS, COATINGS, AND AOHESIVES REPORT *
                                     11-29

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                Figure XI-2

LOCKHEED SANDERS COMPANY STENCIL
          CLEANING PROCESS
       * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                  11-30

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                          Figure XI-3

  LOCKHEED SANDERS COMPANY CIRCUIT CARD
                  CLEANING PROCESS
CIRCUIT
CARDS IS
 CONVEYOR
                                     TO ATMOSPHERE
           WASH
           STATION
                             PROCESS ADt
AD)
KMFE
 RJNSE
STATION
                               FILTER
                                  OLTTSIDE
                                   AIR
                                               HEATER  SLOWER
        AD)
        KNIFE.
HOT AOt
DRYING
STATION
                                               CARDS OUT
          AOITIMIS
          C1EANER
                  AIR
                  KMFE
         FILTER
RINSE
WATER '
FILTEIt


fi
>
AW '
KMFE
/ i


DEIOMZEDWATKR
SYSTEM
                   HI/MI-
                                                  HOCUS A«
                                                         FILTER
                                                            OUTSIDE
                                                             AIM
                                                KEATKR  (LOWER
               * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                             11-31

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III.  BENEFITS & LIMITATIONS

      Some of the benefits of using both aqueous and IPA cleaning processes  in
place of TCA cleaning include:

      •     elimination of the use of ozone-depleting chemicals
      •     effective removal of ionic compounds
      •     components cleaned maintain high surface insulation  resistance
            (SIR)
      «     enclosed equipment reduces vapours in the workplace
      «     lower operating costs

      Limitations of the aqueous and IPA cleaning processes  include:

      « _    IPA is flammable and must be used with extreme care
      «     Alpha 3555 is combustible and corrosive
      «     Alpha 3555 is comprised of several constituents  with low  Threshold
            Limit Values .(TLVs) (two constituents each  accounting for 40% of
            the formulation have TLVs of 3 ppm and 50 ppm)
      «     space required for alternative cleaning systems  is typically
            larger than for the TCA system
IV.   PLANNED PROCESS IMPROVEMENTS

      Lockheed Sanders Company is also evaluating a water  soluble  flux  to
further enhance the soldering process and minimize waste generation.  The  flux
under consideration, Alpha WS-360, is a halide-free organic  flux which  leaves
a negligible amount of residue after the soldering process.   Implementation  of
the water soluble flux would eliminate the use of IPA  in stencil cleaning.


V/    FOR FURTHER INFORMATION, PLEASE CONTACT:

            Mr. Stephen Evanoff
            Lockheed
            980 Kelly Johnson Dr.
            Las Vegas, NV 89119
            USA
            Tel:  1-702-897-3228
            Fax:  1-702-897-6645
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-32

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                 HYDROCARBON DRY CLEANING AT MILJOMINISTERIET
I.    INTRODUCTION

      The Center Rens in Helsinge, Denmark has demonstrated that Satec's
reloading hydrocarbon dry cleaning system can replace CFC-113 as a dry
cleaning solvent for cleaning fabrics and leather.  It has also been
determined that a large portion of perchloroethylene cleaning can be replaced
with hydrocarbon cleaning.
II.   PROCESS CHARACTERISTICS

      The higher initial cost .of the Satec hydrocarbon dry cleaning system  is
a significant factor discouraging Danish dry cleaners from investing in  the
new equipment.  However, the price of a comparable perchloroethylene machine
is expected to increase as future European Community regulations restrict the
use of chlorinated solvents.  At Center Rens, the operating costs for
hydrocarbon cleaning systems are the same as for CFC-cleaning systems.
Hydrocarbon cleaning may also be less expensive for dry cleaning
establishments situated in municipalities which impose high taxes for waste
disposal.

      With the implementation of the hydrocarbon dry cleaning process,
cleaning solvent consumption was reduced by approximately 60 percent.  The  use
of hydrocarbons is estimated to be slightly more than one percent per kg of
clothes cleaned.  Other significant characteristics of the hydrocarbon
technology include:

      •     The consumption of energy which might be increased with
            hydrocarbon cleaning, however, energy use has not been compared.
      •     Water consumption is independent of the technology because cooling
            water is recirculated.
      •     The emission of ozone depleting substances will end.
      •     There will be an increase in the emissions of hydrocarbons which
            contribute to the formation of "smog".
      •     Waste quantity (distillation residue, sludge of textile fibres,
            fluid-containing filters) will remain unchanged, but the character
            of the waste will be changed to flammable oil waste, which is more
            economic to dispose.
      •  '   Wastewater consists of water with a very low hydrocarbon content
            (< 20 ppm).  Cooling units without water recovery also produce
            some wastewater .(80 litres per charge).
      •     Hydrocarbon vapours in the dry cleaning room appear in
                  low concentrations (< 5% of the threshold limit value).
      •     Air change requirements will vary between 3 and 10 times per hour
            most of the year, because of the need to keep the shop doors open
            to allow heat from the process to escape.
      •     Risk to unprotected skin is considered low, but the use of
            protective1 gloves is highly recommended.
      •     The Danish EPA does not consider that flammability is a major
            risk.  However, it is recommended that normal precautions for
            handling flammable substances be taken.
                    * 1994 UNEP SOLVENTS. COATINGS, AND ADHESIVES REPORT *
                                     11-33

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III.  CONCLUSIONS

      The Danish EPA  supported the Hydrocarbon Dry Cleaning project where
hydrocarbons replaced CFC-113  and perchloroethylene in dry cleaning
operations.  The project was carried out successfully without increasing risk
for the workers in  the facility.
IV.   FOR FURTHER  INFORMATION,  PLEASE CONTACT:

            Per Henrik  Pedersen
            Danish Environmental Protection Agency
            Strandgade  29
            DK-1401 Copenhagen K
            Denmark
            Tel:   45-32-66-01-00
            Fax:   45-32-66-04-79
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      11-34

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          PHASING OUT OF OZONE-DEPLETING SUBSTANCES BY THE MINEBEA CO.
                THROUGH THE USE OF A WATER-BASED CLEANING SYSTEM
 I.     INTRODUCTION

       The Minebea Co.  in Thailand and Japan has developed and implemented a
 water-based cleaning system to clean miniature ball bearings and other parts.
 The water-based cleaning system eliminates the use of ozone-depleting
 substances such as CFC-113 and 1,1,1-trichloroethane.  The cleaning .system
 utilizes ultrasound arid deoxidized water and reduces the load on wastewater
 treatment systems by eliminating the need for anticorrosive agents in the
 rinsing process.
 II.    OPERATION OF THE WATER-BASED SYSTEM'

      .The water-based cleaning system operates through the use of ultrasonic .
 energy and deionized water.   Ultrasonic energy in water causes the pitting or
 wearing away of debris from metal' surfaces (a process known as cavitation).
 Use  of deoxidized water in this cleaning process acts both to enhance
'cavitation,  and thus cleaning,  and curbs rusting of steel surfaces because the
 rate of rusting is proportional to the concentration of dissolved oxygen in
 the  water.

       Figure XI-4 is a diagram of a water-based cleaning system.   The par's
 enter the detergent bath,  followed by the rinse bath where deoxidized water is
 added,  and continue on to  the dryer.   The water from the rinse bath is sent to
 the  waste water treatment  system'.
 III.   CONCLUSIONS                                                         •

       The  water-based cleaning system which uses deoxidized water provides
 several  advantages  over other 'cleaning methods.   Deoxidized water enhances  the
 effect of  ultrasonic energy in washing and curbs rusting of steel.   In
 addition,  the  use of a deoxidized system eliminates the need for anticorrosive
 agents in  rinsing and thereby reduces the load on wastewater treatment
 systems.                                       •

       The  Minebea Co.  believes that a water-based washing system must be
 designed to  realize maximum washing effect with minimum water consumption.
 IV.    FOR  FURTHER INFORMATION,  PLEASE CONTACT:

             Morio Higashino
             Minebea Co.,  Ltd.
             4106,  Miyota,  Miyota-cho
             Kitasuku-gun Nagano-ken
             Japan
             Tel:   81-.(0)267-31-1312
             Fax:   81-(0)267-31-1330
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-35

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               Figure XI-4

 MINEBEA COMPANY'S WATER-BASED
          CLEANING SYSTEM
FILTER  ©PUMP  ©FAN
bath no.
1
2
3
4
solvent
detergent
purified and deoxydized water


others
filtering
filtering
hot air
hot air
        1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                  11-36

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                   NON-ODS ALTERNATIVES IN THE CLEANING OF
           INTEGRATED CIRCUITS AT NATIONAL SEMICONDUCTOR  - MALAYSIA
I.    INTRODUCTION          .                                   ,

      As part of a partnership between the Malaysian Government and industry
to eliminate the use of ozone-depleting solvents in cleaning operations,
National Semiconductor in Penang, Malaysia worked closely with, the government
on efforts to find alternatives to the use of ODS in industry.  This effort
lead National Semiconductor to implement changes in its cleaning operations
for Integrated Circuits (ICs).
II.'  SELECTION OF AN ALTERNATIVE PROCESS

      The ODS elimination efforts at National Semiconductor were a result of
active employee involvement in environmental programs, lead by company
management.  The environmental efforts were coordinated by a Task Force
leader.  The Task Force was comprised of representatives from a number of the
company's divisions, including, Process Engineering, Plant Engineering,
Maintenance, Material- Control, and Purchasing.

      The criteria for selecting ODS alternatives included:

      •     quality and reliability of the finished products
      •     workplace health and safety, and environmental impact,
      •     capital investment/Return on Investment (ROI)
      •     Ozone Depletion Potential (ODP)/Global Warming Potential  (GWP)
      •     process flexibility, including transition to new equipment, and
            worker training.
III.  PROCESS IMPLEMENTATION            .           '       .

      In the implementation stage an alternative cleaning process was
identified based on the criteria described above.  In the new  "Green" process,
pre-solder M-Pyrol cleaning step was replaced with a citric acid wash.   In
addition, wave soldering was replaced with solder plating in the new process.
The ODS cleaning in the old process was replaced with a hot deionized (DI)
water rinse, and ambient air drying was replaced with hot air  drying.

      Overall, the "Green" process resulted  in an increase in  output from
18,300 units/hour to 84,500 units/hour.  The new process resulted in very
consistent product quality, while reducing the chemical cost per unit to 1/3
of the original cost.  In addition, the new process equipment  was easy  to
clean and maintain while the original equipment required significant effort to
clean.
IV.   CONCLUSIONS

      'Implementing  the new  cleaning  system  required  a  total  capital
expenditure of $250,000/as  well  as special  training  for workers  on the  new
equipment.  The new cleaning  system  not  only  resulted  in  improved cleaning at


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-37

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National Semiconductor,  but was also a positive  step towards the elimination
of ODS use  in  all  industry in Malaysia.
V.    FOR FURTHER INFORMATION, PLEASE CONTACT:

            X'avier HK Yoong
            National Semiconductor Sdn Bhd
            Bayan Lepas
            Free  Industrial Zone
            11900 Penang
            Malaysia
            Tel:   60-4-837211
            Fax:   60-4-833894
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      11-38
                                        \

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    IMPLEMENTATION OF ODS ALTERNATIVES AT NAVAL AVIATION DEPOT CHERRY POINT
I.    SUMMARY

      The Naval Aviation Depot  (NADEP) at Cherry  Point, North  Carolina  is
responsible for a variety  of  aircraft maintenance activities that  originally
required extensive use of  ozone-depleting solvents.   Since  that.time, cabinet-
style aqueous parts washers,  aqueous ultrasonic processing, and  non-ODS
methods of cleaning parts  by  hand have all been significant steps  towards
NADEP's goal of eliminating ODS use.  While phaseout  .efforts have  depended
upon equipment procurement and  technology development,  the  attitudes of  the
work force and cooperation between departments within the facility have  been
the most important factors in the success of the  program.
II.   INTRODUCTION

      NADEP performs repair, overhaul, maintenance and engineering support
functions on a variety of weapons systems  including  the C-130 aircraft, the H-
46 helicopter, the AV-8B vertical/short take-off and'landing  (V/STOL), and the
V-22 tilt-rotor aircraft.

      Repair and maintenance requirements  frequently required the use of a
wide variety of hazardous or environmentally harmful materials, including
ODSs.  Cleaning prior to inspection, repair, testing or reassembly all r?.lied
on the performance of these types of materials.  The primary substances used
in these cleaning tasks until 1990 were 1,1,1-trichloroethane and CFC-113.

      Large-batch vapour degreasing with 1,1,1-trichloroethane was the
preferred method of cleaning aircraft and  engine components.  Fourteen
degreasers, were in use in 1990 and accounted for the bulk.of ODS usage in.the
facility.  The two degreasers located in the engine  cleaning shop and plating
facility alone consumed 75 percent of the  1,1,1-trichloroethane used in 1990.

      Cleaning parts by hand in bench-top  applications-was another activity
requiring large amounts of ODSs.

      NADEP identified the largest factor  affecting  its overall consumption of
ODSs as being the non-critical use of ODSs in solvent cleaning.  Seventy five
percent of total ODS consumption was for applications for which alternatives
were already available at the depot.  For  this reason, NADEP decided that its
goal should be ODS elimination, not just reduction.
III.  INITIATING CHANGE

      Once NADEP had finished its survey of ODS consumption  in  its maintenance
procedures, it developed an action plan.  The plan  initially focused  on
training the entire workforce that NADEP's goal was  to  eliminate ODS  use.
First, all of the product support engineers were briefed  on  their new      .
responsibilities --to stop specifying ODSs in new  engineering  directives  and
to review existing directives to identify ODS requirements.   Production
artisans also had to be aware of the new mission since  personnel in the
production shops had to be strong allies during this process.   Depot


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-39

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management also took the initiative to include pollution prevention briefings
during regularly scheduled shop safety meetings, focusing the discussion on
specific materials and processes within that shop that would be affected by
the ODS elimination.

      Engineering personnel targeted the largest critical use for its initial
ODS elimination efforts -- the vapour degreasers in the plating facility and
in the cleaning shop.   They required that engineering and shop personnel
accept responsibility to ensure maximum results from any expended efforts.
Engineering personnel first had to identify all uses of the vapour degreasers,
and then investigate and approve alternative cleaning processes.  They also
had to be available during the implementation phase to troubleshoot any
problems that arose.  Shop personnel had to be willing to try new products or
procedures and also had to be committed to working with engineering personnel
to develop alternative processes.

      Management also recognized that while engineering and shop personnel
carried responsibility for.process changes, individuals from throughout the
facility would need to lend support in order to successfully implement change.
A depot-wide effort was undertaken involving personnel in facilities and
equipment engineering, capital procurement and budgeting, environmental
engineering, safety, and.maintenance.
IV.   EXAMINING ALTERNATIVES

      The first alternative investigated to replace vapour degreasing was
aqueous immersion using alkaline detergent.  A variety of cleaning products
were tested using various temperatures, exposure times, parts orientation, and
agitation methods.  After completion of testing, NADEP concluded that this
option would not satisfactorily replace vapour degreasing for its
applications.

      The second alternative investigated was .a cabinet-style parts washer.
The unit applied a hot solution of aqueous detergent at pressures from 40 to
220 psi.  After the initial engineering evaluation, production personnel
visited the manufacturer of the parts washer to evaluate cleaning performance
on actual parts.  After they witnessed the performance of the parts washer,
they became convinced that this technology would perform adequately for their
needs and subsequently procured three units for initial implementation.

      However, NADEP found during implementation that the parts washers were
not effective on all types of soil, and thus did not totally eliminate the
need for the vapour degreasers.  Other technologies were investigated and
NADEP found that for the removal of carbon, wet sodium bicarbonate blast units
were more effective than the parts washers.  Both open-blast and glovebox wet-
type units were procured for this application'.

      Since the technologies had been so successful at supplanting the vapour
degreasers, a date was set to "lock-out"the vapour degreasers in these shops.
Engineering and shop personnel then worked to have the alternate processes
operational in time to meet this goal.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-40

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      During commissioning of the parts washers, NADEP found that, while shop
personnel were pleased with the performance of the washers, it was difficult
to handle the existing work load without .improving the design of the loading
baskets.  Through trial and error, facility personnel developed round,
covered, compartmentalized baskets that greatly improved the shop's
satisfaction with the production of the new process.

      While struggling to eliminate the largest uses of 1,1,1-trichloroethane,
NADEP was also evaluating the largest uses of CFC-113.  The electric motor
shop was using a large CFC-113 ultrasonic unit that consumed 6,800 kilograms
per year in a relatively inefficient manner.  A new ultrasonic unit, suitable
for use with aqueous cleaning solutions was implemented, which performs
equally well.

      To continue its evaluation, NADEP tried cleaning parts previously
cleaned ultrasonically with CFC-113, in one of the new cabinet style parts
washers.  Test results indicated that these parts were cleaned just as
thoroughly by the new aqueous parts washer but with significantly higher
throughput.  The change resulted in a significant reduction in turnaround time
for the parts originally cleaned with CFC-113.
V.    ALTERNATIVES FOR HAND CLEANING

      Non-ODS substitutes for cleaning parts by hand have proven more
difficult to locate than substitutes for batch processes because of NADEP's
many requirements of solvents used in this application.  These requirements
include:                        '                   .           /

    .  •     good performance at room temperature;
      •     good performance without rinsing;
      •     a flashpoint above 140° F; and
      •     the solvent cannot contain any products from the  EPA's list
            of 17 high-priority toxic substances.

      NADEP found some petroleum/terpene products  and aqueous products meeting
MlL-C-85570 Type II to be suitable for many applications.  However., these two
types of materials did not satisfy the requirements of all the depot's clean-
by-hand applications, especially  some precision cleaning tasks.  Processes and
materials are still being evaluated for these applications.

      NADEP's current philosophy  for clean-by-hand applications has been
summarized on videotape and is being used as a training supplement.  The
depot's philosophy dictates the use of batch cleaning methods whenever
possible, with use of the least objectionable chemicals when  cleaning by hand.
VI.   REMAINING ODS REQUIREMENTS         .                         .    .    ,

      Oxygen system cleaning has proven  to be  the most  difficult  challenge  for
ODS elimination.  NADEP  is working  together with the Naval  Sea  Systems  Command
and others within the Naval Air Systems  Team,  in the evaluation of  alternative
materials and processes  for this application.  NADEP is optimistic  that
alternatives will be identified by  the end of  1994.  At the request of  the


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-41.   ,

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North Atlantic Treaty Organization (NATO),  the U.S.  Air Force and the U.S. EPA
are organizing a global effort  to  solve  these problems.
VII.  SUMMARY

      The ODS elimination  effort  at  NADEP has been largely successful because
of the dedication of personnel  throughout the facility toward meeting this
common goal.  The benefits have also been shared by the entire workforce
through reduced costs, reduced  turnaround time,  and pride in protecting
health, safety and the environment.
VIII.  FOR FURTHER INFORMATION,  PLEASE CONTACT:

            Ms. Mary Beth  Fennell
            Naval Aviation Depot Code  345
            PSC Box 8021
            Cherry Point,  NC  28533
            USA
            Tel:  1-919-466-8142
            Fax:  1-919-466-8108
                    * 1994 UNEP SOLVENTS. COATINGS, AND ADHESIVES REPORT *
                                     11-42

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                    CFC-113 ELIMINATION AT NORTHERN TELECOM
.I.     INTRODUCTION                             .

       Over a period of three years beginning in 1988, Northern Telecom
 invested approximately $1 million in a CFC-113 phaseout program.  The
 immediate payoff from this investment was $4 million.  The savings came first
 from conservation measures that reduced purchases of CFC-113 cleaning
 solvents,  and ultimately from the implementation of an innovative "no clean"
 technology that eliminated the need for cleaning altogether.

       When the project 'started,  Northern Telecom was using 1,000 tons of CFC-
 113 each year.  The corporation succeeded in eliminating CFC-113 use from its
 manufacturing operations worldwide in 1992,  which at that time was nine years
 ahead of the date set by the Montreal Protocol (The Protocol has since been
 revised.).                                                        '

       The business case for CFC elimination was not the initial impetus for
 the project, but instead emerged gradually as the project progressed.  The
 decision to undertake such an aggressive environmental challenge to the
 corporation came from a group, of seventy Northern Telecom engineers, who came
 together at an internal CFC Workshop in 1988 to 'consider the impact of the
 Montreal Protocol on the corporation's activities.

       At the time, Northern Telecom, like other manufacturers in the industry,
 relied heavily on the- use of CFC-113 to remove flux residue from printed
 circuit boards.   CFC-113 was considered the most effective cleaner available
 and was relatively safe to use,  with low toxicity and flammability levels.
 The challenge was to find a safe alternative that would satisfy customer
 requirements for high-quality, reliable products  at an affordable price.
 II.    THE PHASEOUT PROCESS

       The CFC Workshop set the ambitious goal of meeting this challenge within
 three  years,  and a Task Force was set up to accomplish this goal.   Management
 commitment to the project, both from the corporate environment function and
 from the  operational side, played an important role in the project's eventual
 success.   The Task Force had access-to the most senior levels of management in
 the corporation,  as well as close working relationships with contacts in each
 of Northern Telecom's forty-two manufacturing plants.

       In  order to "fast-track" the process, the Task Force was organized into
 three  teams,  each of which took on a different assignment.  One team was
 responsible for finding ways to reduce CFC consumption through conservation.
 Initial results from one test location were impressive, and technological
 changes had succeeded in controlling loss and unnecessary evaporation of the
 solvent into the atmosphere.  An improved CFC-113 distribution system included
 a software package, designed by Northern Telecom engineers, that monitored and
 managed metering devices and leak detectors connected to the piping system.
 Within months,  CFC-113 requirements had been reduced by 50 percent.  The
 addition  of activated charcoal absorption reduced the needs still further.  It
 was'estimated that the savings from the decrease in CFC-113 purchases would
 pay for the new technology in under two years.


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     '11-43

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      A second team was responsible for finding effective and safe cleaning
alternatives.  A number of options were considered, including water and
alcohol cleaning processes, and alternative solvents such as terpenes.  The
feasibility assessment for each option took into account a number of variables
including:  process compatibility, flexibility and performance, capital costs,
operating costs, and safety and environmental issues.  In order to assess the
technical feasibility of each option, the team developed a "difficulty index"
that compared the degree of difficulty of using a non-CFC process with that of
the CFC-113 process.  The economic feasibility was evaluated using the net
present value of the two processes.

      The interest of this group was soon caught by the possibility of
eliminating the need for cleaning altogether.  The long-term solution selected
by the team was the "no clean" process, which involves the controlled
application of a low-solids flux containing only alcohol and 1-3 percent
solids.  If properly managed, the residue remaining on the boards after the
soldering process does not detract from product reliability.  A board duster
can test the cleanliness of the circuit board by applying a fine spray of
powder to the surface of the board and measuring weight gain.  When no weight
gain occurs, the board has met the cleanliness standards.

      The crucial factor in implementing the "no-clean" process was ensuring
that customers had confidence in the new process.  The third Task Force team
had been interacting with outside stakeholders in the project.  They had been
sharing project progress with governments, media,. customers, suppliers,
environmental groups, and the general public.  Northern Telecom manufacturing
plants had been working closely with suppliers who were developing new
chemical formulations and fluxes.  In one project, Northern Telecom engineers
collaborated with chemical producers, flux and equipment manufacturers,
government agencies, industry associations, and the U.S. military on .a project
to set cleanliness standards .for circuit boards used by the military.
Customers were involved in shaping and monitoring the testing of the new
technology, and found that the resulting circuit boards were as clean as those
manufactured using CFC-113 cleaning.  In fact, improvements in quality had
actually been obtained.

      By December 1991, all of the locations originally involved in the
project had met the company's CFC-113 elimination target.  Eight of the
fifteen new plants involved due to Northern Telecom's 1991 acquisition of STC
Pic in the United Kingdom had also become CFC-113 free.  The other seven had
committed to eliminating CFC-113 use by early 1992, complying with Northern
Telecom's policy that any new acquisitions would have up to fifteen months to
meet the corporate standard.
III.  TECHNOLOGY COOPERATION

      Cooperation with outside groups had been a key element in the Northern
Telecom project's success.  In 1989, Northern Telecom joined with o'ne of  its
competitors, AT&T, and with the U.S. Environmental Protection Agency  (U.S..EPA)
to form the Industry Cooperation for Ozone Layer Protection (ICOLP -- now
known as the International Cooperative for Ozone Layer Protection).   ICOLP's
continuing mandate is to promote the worldwide exchange of non-proprietary
information on ozone-depleting solvent alternatives.  It now has 12
multinational member companies, and has, as affiliated members, research  and


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-44

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development institutes, environment ministries, military, and noh-governmental
organizations from Canada, China, France, Japan, Korea, Mexico, Russia,
Sweden, Taiwan, Turkey, United Kingdom and United States.

      ICOLP members provide experts to participate in conferences and
workshops, write technical manuals, undertake special projects, and
participate in technology cooperation projects.  One of Northern Telecom's
contributions to ICOLP was the creation of OZONET, an electronic information
system on ozone-depleting solvent alternatives.  The database, now part of the
United Nations Environmental Programme OzonAction database, is available via
modem from many parts of the world.

      Under the auspices of ICOLP, Northern Telecom participated in a 1991
technology cooperation project, working in partnership with the Government of
Mexico, the Mexican association of industries, and the U.S. EPA.  The project
was designed to help the Mexican electronics industry eliminate the use of
ozone-depleting substances through workshops and on-site technical assistance.
The collective efforts of the partners in the program have achieved
substantial success -- a 70 percent reduction in ozone-depleting solvent use
in Mexico.  The program has also introduced Mexican manufacturers to the
latest and best alternative technologies, thereby improving their competitive
advantage in the global economy.

      In 1993, the World Bank agreed to provide ICOLP with money from the
Multilateral Fund set up under the Montreal Protocol, to help ICOLP launch a
"global solvents" project.  This money has paid for part of the cost of
technology cooperation initiatives that have since been launched in seven
countries.  On each project, one or more ICOLP companies have taken the lead
in managing activities in cooperation with a designated host country agency.
Motorola led an initiative in Malaysia, and IBM took the lead in Korea and
Taiwan.  Other ICOLP companies have partnered with the Japan Electric
Manufacturing Association and the Japanese Ministry of International Trade and
Industry to lead a cooperative effort with industry and the government of
Thailand.  This year, the Ministry of the Electronics Industry in China agreed
to work in partnership with Northern Telecom on a program to help the Chinese
electronics industry eliminate the use of ozone-depleting substances.
Northern Telecom served as project manager for an initiative' in Turkey, will
lead workshops in India, and is starting to plan projects in Brazil and
Vietnam.            .                                   .

      Northern Telecom's leadership in CFC-113 elimination and its willingness
to share its experience have brought it international recognition, including
three prestigious awards:  the U.S. Environmental Protection Agency's
Stratospheric Ozone Protection Award, the United Nations Environment
Programme's North American Leadership Award, and the U.S. President's
Environmental and Conservation Challenge Award for Innovation.
IV.   CONCLUSION                                                   •     •    '

      While the environmental challenge set by the Montreal Protocol was  the
spark for this ambitious project, Northern Telecom has seen direct business
benefits.  These include direct cash savings, a heightened international
reputation for environmental leadership, and  improved relationships with
customers, suppliers, government agencies and other stakeholders.  This


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-45

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experience has created an atmosphere of management support  for  environmental
projects, and opened the  door for new initiatives in such areas as product
life cycle management and environmental management systems.
V.    FOR FURTHER  INFORMATION,  PLEASE CONTACT:

            Elizabeth  H.  Rose
            Northern Telecom
            3 Robert Speck Parkway
            Mississauga,  Ontario L4Z 3C8
            Canada
            Tel:   1-905-566-3270
            Fax:   1-905-566-3348
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      11-46

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             REPLACING SOLVENT CLEANING WITH AQUEOUS  CLEANING AT
                           ROBERT BOSCH CORPORATION
I.    SUMMARY
                            /

      Robert Bosch Corporation's Charleston, South Carolina plant has been
successful in replacing ODS cleaning solvents with non-chlorinated solvents.
The technologies implemented have all cleaned as well or better  than the
original chlorinated solvents and have done so with reduced capital costs and
similar or reduced labour costs.  This result is due in part  to  the fact that
ODS usage has been eliminated at a time when ODS prices have  more than
tripled.  In addition, by using this opportunity to implement more energy
efficient technologies in the phaseout process, the electric  costs for its
cleaning processes have been cut in half.  Bosch is convinced that the time
and resources already spent in converting from chlorinated solvents have been
a good investment, and the company will continue to pursue these activities
until all trichloroethylene (TCE) and hydrocarbon solvents have been replaced.

      To date, Bosch has eliminated all CFC-113 usage and .two thirds of its
trichloroethylene (TCE) usage.  The company's goal is to be completely free of
chlorinated solvent usage by the end of 1995.  These changes  in cleaning
processes have not only responded to the environmental goals  of the Montreal
Protocol and EPA's 33/50 Program, but 'have also resulted in improved cleaning
at significantly reduced costs.
II.   INTRODUCTION

      The Robert Bosch Corporation is a U.S. subsidiary of Robert Bosch GmbH
of Stuttgart, Germany.  Bosch's Charleston plant manufactures automotive
products and is the largest plant in the U.S. subsidiary, with about 1,700-
people working in 600,000 square feet of manufacturing space.  The plant has a
heavy engineering emphasis in support of its assembly and test functions.

      The primary products produced in the plant are gasoline fuel injectors,
anti-lock brake systems, and diesel fuel pumps.  The metal parts manufactured
in the plant were cleaned with CFC-113 and TCE.  The company plans to
eliminate the use of TCE in support of the EPA's 33/50 Program and in response
to the availability of improved cleaning efficiency and product performance
associated with new replacement cleaning technologies.  Eliminating
chlorinated solvents on'the production floor required a large team effort.
Team participants included the plant manager, planners and users of the
solvent replacements, and other support personnel.

      The implementation of non-chlorinated solvents began in early 1990.  By
the end of 1992, all CFC-113 use had been eliminated by'adopting alternative
technologies.  These processes are continually being reevaluated and improved;
certain types of replacement processes described have been superseded by newer
measures, and additional upgrades will continue to be introduced.

      A key decision made early in the process was to replace the Company's
large aging central degreasing stations with a number of small cleaning units,
each designed and dedicated for cleaning just one type-of part at one step in
the product assembly process.  This strategy required reassessment of each


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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cleaning step and the identification of equipment and chemistry for optimizing
each aqueous replacement.

      As a result of this decision, annual use of approx. 247,000 kg of CFC-
113 use has been eliminated at the Charleston plant, along with the approx.
41,000 kg of TCE.  In addition, major cost savings have been realized by
implementing more energy efficient aqueous cleaning technologies.  The
Company's records indicate that the combined costs of chemicals and
electricity have been significantly reduced, reflecting both the elimination
of all CFC solvent cleaning as well as the switch from a few large central
cleaning stations to many small dedicated cleaning units.
III.  DESCRIPTION OF PARTS CLEANED AT THE CHARLESTON PLANT

      Most of the parts cleaned in the plant are for two assemblies: a fuel
injector and an anti-lock brake system.  Some parts are cleaned more than once
during the assembly process, resulting in over 30 separate cleaning
operations.  The parts to be cleaned generally consist of mild steel,
stainless steel, plastic, and rubber, and contamination to be removed
typically incudes metal chips and fibres, grinding coolants, shop dirt,
chemical residues, and fingerprints.

      Cleaning operations at Bosch include both gross cleaning and precision
cleaning.  Gross cleaning is carried out on the open production floor, and
precision cleaning is performed in the Class 10,000 clean room where final
assembly takes place.  Inadequate cleaning can compromise product performance
and may result in failures.  While the cleaning requirements are less than
those of the semiconductor or disk drive industries, part cleanliness at Bosch
means more than simple washing or scrubbing in soap and water.  Particles
larger than about 25 /tm are of concern and are targets for removal by the
cleaning process.
IV.   PREVIOUS SOLVENT CLEANING TECHNOLOGY AT THE CHARLESTON PLANT

      In 1988, all cleaning operations for manufacturing were performed using
either CFC-113 or TCE.  Typically these cleaning steps were carried out in
large centrally located degreasers.  Eight units used TCE and seven used CFC-
113.  These degreasers were off-the-shelf, commercially available units, and
all included some form of solvent recovery.  The units used combinations of
spray and ultrasonic agitation in addition to vapour degreasing to dislodge
the contaminants.

      Both the TCE and the CFC-113 units served as general purpose cleaning
stations for the various cleaning steps required in manufacturing.  Parts
passed through the cleaning station in their order of arrival, and .the
throughput time for baskets containing a total of 27 to 45 kg of parts was
typically about 40 minutes.  In this operating mode, solvent consumption in
1988 was 247,000 kg of CFC-113 and 60,000 kg of TCE.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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V.    OPTIONS FOR REPLACING CHLORINATED SOLVENTS

      Options considered for replacing chlorinated solvents included "no-
clean" ,  other organic solvents, aqueous cleaning, and supercritical carbon
dioxide.  The most desirable option considered was the no-clean option.  In
evaluating no-clean manufacturing, the cleaning step was first examined to
determine if cleaning was absolutely necessary.  Sometimes the cleaning step
can be eliminated with minor or no changes to the rest of the manufacturing
process.  Successful replacement of a chlorinated solvent with a no-clean
process is a relatively rare event, but has large benefits in reduced costs
and cycle time.

      An example of this type of process change at Bosch was the replacement
of solvent cleaning of a part between two machining steps.  In the no-clean
process, the oil-based lubricant is centrifuged off the parts, eliminating the
wash and rinse cycles formerly used to clean the part.  This eliminated a
waste stream and, reduced the cycle time, chemical usage, and floor space
required.  The implementation of this no-clean technology was the result of an
idea originated by shop floor manufacturing personnel.

      For those operations for which no-clean technologies were not feasible,
Bosch chose to bypass interim alternatives such as hydrbchlorofluorocarbon
(HCFC) solvents.  It 'also was decided not to revert to the hydrocarbon
cleaners used in earlier years.  The Company's decision was to immediately
address the long-term environmental issues associated with cleaning and to
develop cleaning methods that would be as permanent as could be conceived
under current knowledge and regulations.

      The next option considered was aqueous cleaning.  Aqueous cleaning with
deionized water has proven very effective, especially when customized for a
specific cleaning step on a specific part.  The costs of deionized water
cleaning become affordable when used in the limited quantities required by
small, dedicated cleaning stations that incorporate reuse of the water before
discharge.  Bosch team members decided that parts cleaning could best be done
with small custom cleaners dedicated to one or a few cleaning steps, which was
a major change from the large central cleaners of 1988.  This change
eliminated any possibility of cross contamination, shdrtened cycle times, and
allowed better matching of each cleaning process to the specific part and
contaminants.  The switch from large central cleaners to small custom units
has improved part cleaning efficiency and reduced solvent losses.  The
introduction of single function washers for critical cleaning tasks was made
easier by the fact that much of the existing cleaning equipment was 10 years
old and in need of replacement.  Particles larger than 500 /im were not being .
removed from parts in some of these units, and the Company felt that
retrofitting or modifying the existing equipment would have been both
expensive and short-sighted.  Selecting new, customized equipment, however,
required careful analysis of many cleaning steps..
                ^                           '              ,
      The team reviewed other options for replacing chlorinated solvents, but
did not select them for testing.  Some, like supercritical carbon dioxide
cleaning, were expensive and not production-ready.  The primary reason for
dismissing other options, however, was that aqueous replacement technology .had
more advantages and fewer potential drawbacks.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
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VI.   CLEANING PROCESS SELECTION

      Bosch uses two tests to evaluate the cleanliness of parts and the
effectiveness of cleaning techniques.  The first is a visual inspection.
Parts are inspected for contaminants including fibres, dust, and machining
debris.  In a second test, lots are periodically audited by a five minute
ultrasonic extraction of one basket of parts from the lot in petroleum
distillate.  The particles released during the extraction are collected on a
filter with a 5 /urn pore rating and weighed to assess cleanliness.  Control
charts plotting reject rates from both the visual inspection and the
extraction test monitor the efficiency of the cleaning process.

      Supporting tests may be carried out in a vendor's facility but vendor
data have generally played a minor role in the replacement team's decisions.
Time lapses between vendor cleaning and evaluation at Bosch hinder the use of
this approach.  New process evaluation at Bosch is typically performed on
production equipment made available for tests during off-peak hours.  Either
an existing production unit is modified or adapted to a new process, or a
prototype production unit is ordered from a vendor.  Modifications and fine
tuning are then carried out on the production scale units before the new
process is incorporated into an ongoing production line.
VII.  HARDWARE SELECTION

      Solvent replacement selection at Bosch has always started with the
selection of the cleaning process and associated hardware, such as
ultrasonics, high-pressure spray, or turbo washing, rather than the selection
of a cleaning solvent or fluid.  .The argument for this approach is that there
are hundreds of chemicals to choose from but only a handful of cleaning
processes.

      To rapidly identify suitable aqueous cleaning hardware, Bosch first
investigated off-the-shelf washing equipment.  If off-the-shelf units proved
ineffective or were not available, Bosch retrofitted existing equipment or
engineered custom units of its own design.  In one application, it converted a
low-pressure spray washer to high pressure; in another, a high pressure unit
was modified to use water instead of CFC-113.  A turbo washer has also proven
successful in aqueous cleaning of certain parts, but no single piece of
hardware has been suitable for all cleaning applications.

      Drying following wash and rinse was a sensitive issue for Bosch.
Functional requirements typically require that all water be removed before the
next operation.  Removal of water by heating the parts often produced
unacceptable spotting.  Centrifuging at,room temperature aftep aqueous
cleaning has now become the drying technique adopted almost universally by
Bosch.  The centrifuges used provided the option of warm air circulation
during the spinning, but this drying assistance has often not been necessary.
VIII.  CHEMISTRY SELECTION

      Compatibility of a chemistry with a part is determined by the Bosch
chemical and metallurgical laboratories.  These tests for chemical
compatibility and absence of part degradation take 24 to 96 hours and are


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conducted before introducing any chemical  into production.   Safety
considerations  (flammability or toxicity)  caused  some  solvents  to be
eliminated from consideration.  The production floor itself  then became  the
laboratory for  final acceptance tests.  Reasons for rejection included poor
cleaning in production and objections  from production  personnel concerning
solvent odour or part appearance after cleaning.

      All but one replacement solution adopted to date has consisted  of
deionized water alone or deionized water with an  alkaline cleaner.  The
specific additives and surfactants used in the cleaning  steps were  selected  to
be compatible with the part being cleaned, the soil being removed,  and the
cleaning equipment used.  These decisions  involved experimenting with various
proprietary products to confirm rust protection and satisfactory soil removal.
For example, oil-based lubricants are  used for machining the parts.   The parts
are cleaned in  aqueous systems with chemistries that allow the  oil  removed to
separate from the water.  Oil is then  removed from the tanks in most
operations by skimming or gravity separation in holding  tanks,  and  is
subsequently shipped off-site in sealed containers for disposal.

      Parts cleaned by an aqueous.replacement method typically  had  a  different
feel and appearance than those cleaned with a chlorinated solvent.  They
appeared dull and often had a different colour and some  visible water spots.
These obvious differences worried production personnel who were slow  to accept
the new cleaning process until they adjusted to the new  acceptance  tests and
received assurances from the Quality Gauging Department  that the new  cleaning
process was adequate.  Only after a transition period, which varied frop part
to part and was as long as six months, did production  personnel accept
ownership of the new cleaning apparatus.   Until this confidence was built, all
breakdowns, equipment, and performance problems were immediately passed back
to the replacement team.  Once transfer of ownership was completed  on one
part, acceptance for other parts developed more easily and quickly.
IX..   FOR FURTHER INFORMATION, PLEASE CONTACT:

            Mr. Charles H. Darvin
            U.S. EPA
            Air & Energy Engineering Research Lab, MD-61
            Research Triangle Park, North Carolina 2771V
            USA
            Tel:  1-919-541-7633
            Fax:  1-919-541-0361
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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         USE  OF A LOW RESIDUE FLUX IN A MILITARY ELECTRONICS PROGRAM
I.     SUMMARY

      Rockwell Tactical Systems Division (TSD) and the U.S. Army Missile
Command collaborated in a fifteen-month long evaluation of low-residue fluxes.
The evaluation was specific to the options for the AGM-114 Hellfire Missile
assembly line, and two of the new fluxes tested were eventually qualified for
use.  In July 1993, 'Hellfire became the first U.S. Army production program to
implement low-residue flux technology.  Today this technology is used in all
of the assembly line's processes:  wave soldering, lead tinning and hand
soldering.
II.   INTRODUCTION

      In developing its ODS elimination program, Rockwell TSD first conducted
an ODS usage survey.  The survey revealed that  its greatest use of ODSs
involved rosin-based flux removal.  1,1,1-Trichloroethane was being used  in
batch degreasers, in-line solvent .cleaners, and for manual brush cleaning,
with consumption levels at 32,000 kg per year.

      The objectives of the program were to:

      •     minimize the number of new chemicals brought into the
            division;                              <
      •     keep capital expenditures for new equipment low;
      •     maintain weapon system performance  and reliability; and
      •     minimize the impact of implementing a new cleaning
            technology on a production line that consistently produced
            defect-free circuit cards (CCAs).

      Rockwell TSD produces several products for the Army and the Air Force,
so in selecting a candidate production line for its first alternative
technology trial, the company had many products to choose from.  Since its
highest volume product was the Hellfire Missile, this choice offered the  most
hardware for testing.  Although all the Hellfire circuit cards are strictly
through-hole (no surface-mount) ,. some contain high density areas of moisture-
sensitive circuitry.  It was felt that Hellfire hardware would provide "worst-
case" 'testing, and data collected during testing could be applicable to the
other programs.

      In formulating the ODS elimination program, a number of strategies  were
considered.  The company first considered solvent-based technologies as a
replacement for 1,1,1-trichloroethane.  However, this proposition had several
problems.  For example, many alternate solvents:

      •     are hazardous to some degree;
      •     are expensive to produce;
      •     require special handling;
      •     require special storage conditions;
      •     require costly disposal techniques;
   .   •     are relatively new with, little usage history;
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      •      are undesirable  for  global  warming,  toxicity,  or other
             reasons;  or
      •      require expensive  equipment for use.

      Rather than  focus  on finding  and  testing solvent replacements  for 1,1,1-
trichloroethane, Rockwell  decided that  a preferable'approach would be simply
to eliminate use of rosin  flux.   Preliminary lab  tests were  performed with
both no-clean (low-residue)  and  water soluble fluxes.   Five  non-rosin no-clean
fluxes and six water-soluble organic acid fluxes  were  selected for the initial
test.  These preliminary tests evaluated:

      •      capability to  solder plated-through-holes;
      •      effectiveness  in tinning aged component  leads;
      •      ionic  cleanliness  following a warm deionized water rinse;
             and
      •      solder mask  effects..

      The soldering performance  for most  of the flux samples was  found to  be
adequate with two  of  the no-clean fluxes  having outstanding  results.   While
not expected to match the  performance of  the organic acid -(water  soluble)
formulations,  the  no-clean fluxes surpassed the RMA-type flux used as  a
control.  With this finding, Rockwell decided to  only  continue testing the top
two no-clean fluxes,  thereby avoiding the problems associated with removing
organic acid residues caused by  their corrosive characteristics.

      One early finding  was  that the no-clean residues  interfered slightly
with the adhesion  of  some  conformal coatings.  This  problem  was resolved by
washing the  residues  off with a  saponified water  cleaner prior to coating.

      Based  oh this favourable preliminary data,  a straw-man qualification
plan was presented to the  Army's Missile  Command, Hellfire Project Office,
and Product  Assurance Directorate.  The Army agreed  to  partner with Rockwell
TSD and co-sponsor the qualification effort.    *  .
III.  FLUX QUALIFICATION

      A solder lab was established exclusively for  the purpose of evaluating
flux performance on coupons and circuit cards, providing  the ability  to
conduct the study without exposing deliverable hardware to non-compliant
chemicals.  This lab was equipped with an Electrovert 400SV wave solder
machine, a Branson precision batch cleaner, and a Zero Ion cleanliness tester.
Manual soldering stations were set up to allow assemblers to try the  new  low
residue cored-wire fluxes in simulated touch-up practices.

      A test scenario was developed  from available  information.  At the time
of this evaluation design, no documentation existed with  definitive DoD flux
qualification requirements (although Bellcore had a TSY document that was
available, and a draft of MIL-STD-2000B offered a test plan).  Criteria was
established and agreed upon by all Army and Rockwell team members.  Following
is a brief description of the tests  that were performed in the qualification
effort.

Surface Insulation Resistance (SIR)  Testing.  Pre-cleaned IPC B-24 Test Boards
were prepared-by fluxing and wave soldering with the comb patterns in the


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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bottom-side and top-side configurations.  Some test boards were cleaned using
a saponified water wash; the rest were not cleaned.  Hand soldering was also
performed on test boards using the equivalent flux formulations in cored
solder wire.  RMA fluxed and soldered test boards were tested along with the
new flux boards.  Pre-cleaned non-soldered test boards were used as controls.

      The test consisted of subjecting the boards to 85°C and 85% relative
humidity conditions for 28 days with a 50-volt DC bias applied.  A reverse
bias of 100 volts was placed across the comb pattern and resistance
measurements taken every 24 hours.  All patterns were continuously monitored
for any resistance breakdown caused by dendritic growth across conductor
patterns.  Boards successfully maintained SIR values well above the IxlO8 ohm
requirement.

Corrosion testing.  This test was performed using the standard copper mirror
method described in IPC-TM-650.  Both fluxes were certified to be halide-free
by their respective manufacturers.

Production hardware testing (CCA).  Hellfire circuit cards with known
sensitivities to moisture were assembled using the new fluxes.  They were then
subjected to the maximum expected.system temperature (63°C) and 85% relative
humidity for seven days, while under the 12 volt potential normally used in
operation.  No  flux related anomalies were observed.

System Qualification Testing.  As a final test for the Hellfire system, all
CCAs were soldered with the new fluxes and assembled into the respective upper
level modules using the no-clean wire'solder.  Modules were powered (18 VDC
and 28 VDC) and subjected to 63°C and 85% relative humidity conditions for
seven days.  Following this treatment all modules were inspected and found to
be functionally sound.


IV.   FACTORY IMPLEMENTATION

      On July 28, 1993, Rockwell converted the Hellfire production line to no-
clean or low-residue flux.  All rosin fluxes and rosin-cored solders were
removed from the work stations.  Several months prior to this activity, a task
group from Operations had generated a comprehensive checklist of all items
that would be affected by the flux change as part of an implementation plan.
Rockwell addressed those processes affected by the flux and processes that
relied on the use of 1,1,1-trichloroethane, which was to be eliminated after
the new flux was introduced.  The company's plan detailed each activity and
listed its priority, the person(s) responsible for the'activity, and a
schedule for completing the activity.

      Examples of items affected by the plan were:

      •     process sheets;
      •     training manuals;
      •     new chemical forecasts;
      •     waste disposal; and
      •     new process control procedures/equipment.

      During the testing phase, it was determined•that spraying was the
optimum method to apply flux.  Therefore, the receipt and installation of a


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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spray fluxer was a major item on the list to be completed.  Because low-
residue flux is contained in a sealed reservoir, no significant evaporation
occurs, reducing the need to monitor flux consistency.  In addition, no flux
need ever be discarded due to contamination or oxidation.  Solder defects on
the evaluation assemblies were .very low  (one. to two defects per card), but
higher than those with the RMA process (normally averaging 0.7 defects per
card, or-99.9% defect free).  Initially, the number of defects using the no-
clean flux averaged around 6 per card.  However, by fine-tuning the process
over a four month period, defect levels were reduced to below the best results
achieved with RMA-type fluxes.

      The fumes from the new flux were found to be irritating to some
employees.  Fume extractors were installed on the soldering irons to rectify
this problem.  Many operators have found that in most cases, the new solder
wire performed better than the RMA-cored wire, with the exception of tinning
stranded wires.  None of the low-residue' fluxes have been found to adequately
tin the inner strands and prevent "birdcaging."
V.    OBSERVATIONS AFTER EIGHT MONTHS            .     .

      The decision to-use low-residue flux has proven to be  the best option
for Rockwell TSD.  Defect levels have generally  remained at  or below those
experienced with RMA fluxes.  It is  important to note the  low-residue  flux is
less "forgiving" than rosin-cored flux.  When, parts were highly solderable,
few problems with the low-residue flux were encountered;   however, when parts
were marginally solderable,  low-residue  flux performance was not  so good.
Problems with solderability  typically have been  traceable  to isolated  lots of
boards or components.               .   '  t

      As mentioned previously, solder-plated stranded wire is very difficult
to tin with the new flux.  The use of higher levels of flux  solids and
ultrasonic solder pots have  failed to solve the  problem..   However, silver- ,
plated stranded wires appear to tin  very well.

      Wave solder processes  established  for the  rosin fluxes tend to evaporate
the low-residue fluxes too quickly,  resulting in a very dry  board and  poor
through-hole wetting.  In addition,  the  low-residue fluxes to increase the
amount of solder dross generated.  Dross reducers are being  used  to alleviate
this problem.  An inert atmosphere may also help, but has  not yet been tested.
The anticipated change in solder joint shape and brightness  did not appear, so
a recalibration of inspectors was not required.  Finally,  since the' fumes were
more irritating than those of the RMA-type flux, ventilation was  increased,
especially around the spray  fluxer areas, and hand solder  work stations.

      In addition to being a technical success,  this  project has  demonstrated
the achievements possible by a cooperative effort between  government agencies
and industry.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
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VI.   FOR FURTHER INFORMATION, PLEASE  CONTACT:

            Ralph Vaughan
            Rockwell International  Corporation
            Tactical Systems Division
            1800 Satellite Boulevard
            Duluth,  GA 30136
            USA
            Tel:   1-404-497-5222
            Fax:   1-404-497-5555
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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             THE CLEANING CENTER SYSTEM OF SEIKO EPSON CORPORATION
I.    SUMMARY

      Almost all manufacturers  share production  responsibilities  with
suppliers.  This allows  them  to "borrow"  individuals with  technical
experience, maximizing the  efficiency  of  their own human resources.  Under
this co-production arrangement,  manufacturers can make high-quality  products
faster and at. lower cost than otherwise possible.  This  arrangement  also  lends
itself to solving shared problems,  including environmental  problems  such  as
ozone depletion.

      Without such cooperation,  small- and medium-sized  companies may have
difficulty in finding ways  to establish alternative technologies  and introduce
new equipment without interfering with production.  In addition,  they may be
hampered by:

      •     poor investment payback;
      •     limited floor space;                           .,   .      '
      •     lack of technical expertise regarding cleaning  machinery and
            solvents, making  them overly  reliant on equipment/solvent
            manufacturers for technical assistance; and
      •     a small labour  pool with few,engineers.

      Given these limitations,  small-  and medium-sized companies  may not  be
able to eliminate use of ODS  on their  own.  Moving to alternative cleaning
processes is not simply  a matter of transferring technology from  larger
companies.  The Cleaning Center System of Seiko  Epson is designed to address
these problems.
II.   INTRODUCTION

      Like many other small- to medium-sized companies, Seiko Epson has opened
a cleaning center equipped with non-ODS cleaning equipment.  Seiko Epson has
invited many of its parts suppliers to share the use and expenses of this
cleaning center.  The center is designed to eliminate ozone-depleting
substances from production processes.                           •   •
III.  THE CLEANING CENTER SYSTEM

      The Cleaning Center is a way to share ODS-free cleaning equipment with
suppliers of Seiko Epson.  The primary benefit  of a common cleaning center  is
an opportunity to share costs while preventing  pollution.  The system  is.
described in. Figure XI-5 using the printed circuit board manufacturing process
as an example.

      First, Seiko Epson supplies the subcontractor (supplier) with printed
circuit board (PCB) parts.  The subcontractor then mounts these parts  oh  PCBs.
Next, the mounted PCBs are transported to Seiko Epson to be cleaned by Seiko
Epson's ODS-free cleaning process.  After the boards have been cleaned, the
subcontractor transports them back to its own plant, inspects them and makes
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT * ,
                                     11-57

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                   FigureXI-5

SEIKO EPSON CLEANING CENTER SYSTEM
             SEIKO EPSON CORP.
          PARTS CONTROL
         MANUFACTURING LINE
           THE CLEANING CENTER
                /  MO\
   MOVEMENT OF
VPARTS TO BE CLEANED/
       MANUAL
       INSERTION
   SOLDERING
INSPECTION/  •

  REPAIR
                  SUPPLIERS
          1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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any necessary repairs.  Finally, the finished products are delivered to Seiko
Epson.               '      ;

      In the present arrangement, the CDS-free cleaning equipment  is used  24
hours a day.  From 8:30 AM to 5:00 PM, products entirely manufactured by Seiko
Epson are cleaned.  The remainder of the day is scheduled for supplier use,
with employees of Seiko Epson running the cleaning operation.  Suppliers can
deliver dirty parts and pick up clean parts 24 hours a day.

      The layout of the cleaning operation is shown in Figure XI-6.  Some
general technical information about the cleaning equipment is given below:

      •     System size:  1.6 m X 5.86 m.
      •     Conveyor speed:  0.8 m/min.
      •     Cleaning capacity:  1.6 to 1.7 million parts/month.
      •    • USQ restricted to glass epoxy circuit boards with maximum
            width of 400 mm constructed using lead wires or  SMT.
      •     Parts can extend up to 80 mm from the surface of the
            conveyor belt.       .                 '        .
      •     Pure water feeding device:  30 litre ion replacement tower.
      •     Pure water control ration resistance value:,  1 us/cm.
      •     Two-tiered float switch used to monitor water levels in each
            bath.              .                                     .     .   -

      The bath configuration is in-line and uses- a conveyor  belt.   It has
showers that simultaneously clean the top and bottom surface of printed
circuit boards.  The system has three zones - saponifica.tion, rinsing, and
drying.  It uses a closed system so wastewater treatment is  not required,  and
the cleaning machine works for more than one specification1of circuit board.
The speed of the cleaning machine can be adjusted such that  only one person is
required for normal operation of the system.
IV.   ISSUES

      Each supplier  is responsible  for  controlling  its produces.  A  cleaning
order is attached to each  lot of products  and all work is  carried out  on  the
basis of the order.

      Some advantages of the system and equipment-sharing  arrangement  include:
      •     high equipment investment efficiency;
      •     better cleaning results than old system;
      •     .consistent cleaning quality;
      •     lower cleaning costs; and
      •     lower expenditures for  energy  and solvents.

      Disadvantages  include longer  lead times and higher transportation costs
since suppliers are  required to transport  their  products to  the  cleaning
center.  Prior to their use of the  Seiko Epson Cleaning Center System,  the
cleaning process was integrated into their own manufacturing system.   The
Cleaning Center was  designed for 24-hour-a-day operation to  help alleviate
these higher costs.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                                   Figure XI-6

                     CLEANING  CENTER LAYOUT
BARKING TERMINAL
  I HADING DUCK
  KIR SUI'Pl.lbRS
  PRODUCTS
                   STOCK AREA FOR

                 CLEANING PRODUCTS
                       Conveyor belt -
                       transporting
                       cleaned products
                              I
Cleaning Machine
                              I.UADINli IXK.K
                              KOR SlilKOKI'SON
                              I'RODl'CTs
                          SEIKO EPSON
                          MANUFACTURING
                          PROCESSES
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      Prior to the Cleaning  Center  opening,  suppliers  picked up Epson-supplied
parts and delivered finished products.  Under  the  common cleaning center
arrangement, however, they were  initially  required to  make an extra trip in
the middle of the production process  to have their products cleaned.   This
factor increased their transportation costs.   To maintain transportation costs
at the previous level,t Seiko Epson  adjusted  its delivery schedules' so that a
truck runs a regular route that  covers all suppliers twice a day.   In the
first round, Seiko Epson delivers cleaned  parts to the suppliers and picks up
finished products.  In the second round, Seiko Epson delivers parts to  be
packaged and picks up boards to  be  cleaned.
V.    CONCLUSION

      Smaller enterprises may sometimes need  the  cooperation  of  larger
companies if they are to achieve a  total phaseout of  ODS before  the January  1,
1996 deadline.  Seiko Epson believes  the common cleaning center  arrangement  is
an effective way to help small- and medium-size companies  eliminate ODS.

      Seiko Epson also believes that  the Cleaning Center System  can be  easily
applied to many industries in many  countries.  The company recommends
retaining technical experts in the  various relevant fields during  the
transition period to efficiently manage any problems  that  may arise.
VI.   FOR FURTHER INFORMATION, PLEASE CONTACT:

            Kaichi Hasegawa
            General Administrative Manager
            Environmental Affairs Manager
            Seiko Epson Corporation
            3-5, Owa 3-Chome, Suwa-Shi
            Nagano-Ken, 392 Japan
            Tel:  81-266-52-3131
            Tel:  81-255-58-0416 (direct)
            Fax:  81-266-58-9584
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-61

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          THE ODS-FREE VERIFICATION SCHEME FOR SINGAPORE INDUSTRY
I.     INTRODUCTION

      The project to develop an ODS-Free Verification Scheme was begun in June
1993 by the Singapore Institute of Standards and Industrial Research  (SISIR)
as a means for companies to demonstrate (via third-party proof) that  they are
not using ozone-depleting substances in their manufacturing processes.  The
Scheme is open to local manufacturers in Singapore and has t le support of the
Singapore Economic Development Board (EDB) and multinational companies (MNC)
through the Local Industry Upgrading Program (LIUP).  MNCs and large  local
companies contribute program managers to LIUP in the planning and
implementation of programs for upgrading the technology and business  of local
vendors.

      The SISIR Scheme provides several services to companies.

      •     It provides public recognition for companies who have phased out
            ODS in their manufacturing processes.
      •     It provides MNCs and international purchasing offices (IPO) in
            Singapore with a source of independent verification and eliminates
            the potential for multiple audits.
      •     It makes it easier for participating companies to export  products
            to countries such as the U.S., since the U.S. Clviau Air Act
            requires the labelling of imports that are manufactured using
            substances which are harmful to the ozone layer.
      •     It provides technical assistance from SISIR to companies  who are
            switching to ODS-free alternatives as well as corr"ltation on the
            means to obtain verification.

      SISIR's Chief Executive, Mr. Khoo Lee Meng, believes that no other
signatory to the Montreal Protocol has a national verification scheme similar
to that established in Singapore.
II.   REASONS FOR THE ODS-FREE VERIFICATION SCHEME

      The industry's need for an independent, third-party verification  scheme
was identified through the LIUP's network of MNC-partners.  The necessity  for
this type of verification scheme arose as a result of the following  issues:

      •     The current worldwide 'green' movement.
      •     The imposition of the ODS phaseout schedule under  the Montreal
            Protocol.
      •     Many of Singapore's trading partners require imports to  be
            ODS- free.
III.  VERIFICATION PROCEDURE

      Companies participating in the verification  scheme  follow  an  established
procedure:
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                     11-62

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      •     The applicant company submits flow charts, discloses the chemicals
            used in th    .aufactu:  _ process  .  nd indi      if th<    .-any
            has obtained or is seeking.ISO 9000 certification.
      •     SISIR conducts audits of the company.  SISIR examines supporting
            documents and doc'nnentation ~-ocedures, -nd tests s—ap^is of
            chemicals employed in manufacturing to verify that .no ODSs are
            being used.
      •     Following initial certification, the company is periodically
            surveyed to ensure compliance with the terms and conditions of  the
            Verification Scheme.

      The verification procedure costs local companies between U.S.$4,000 and
U.S.$8,000.   To help local companies defray the cost of verification, the  EDB
offers financial assistance under the Local Enterprise Technical Assistance
Scheme (LETAS).  Grants of up to-70% of the cost are -Carded to companies who
seek verification before December 1994:  After December 1994, grants of up ^to
50% of the cost will be available to companies.
IV.   SUCCESS OF THE VERIFICATION PROGRAM

      Companies cited a variety of reasons why they participated in the
verification program.  For example, New Electronic Technology joined the
Scheme because several of its customers ship their products to the United
States and these products need to be labelled.  Micro-Team Industries, which
used solvents to chemically coat electronic parts and other objects with
metal, stopped using these solvents in order to protect the health of  their
workers.  SEA Trading Co. said they participated to demonstrate to the public
their belief that environmental protectioti .is important.

      Since the verification program began, more than 40 companies have
expressed interest in seeking verification.  As of March 1994, eight companies
had received verification.  As of August 1994, Leica Instruments, a
multinational company which produces precision optical components, had been
successfully audited.  Another multinational company, SONY Display Device,
which produces colour television tubes, is ready for the pre-award audit.  In
addition, thirty companies are currently in various stages of application for
verification.

      The eight companies which have received certification for having stopped
using ODS in their manufacturing processes are primarily plastics moulding and
electronics components manufacturers.  Six of these eight companies are in the
EDB's LIUP:  .                                                        .

            Hi-P Tool & Die
      •     Next Electronic Technology
      •     Mould Technic
      •     Micro-Team Industries        .
      •     Joetsu Engineering Plastic
      •     Chartered Electronics Co.

      The remaining two companies which received certification are:

     ••     Singapore Asahi Chemical & Solder Industries
    •  •     SEA Trading  Co.                                            '


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-63

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      Table XI-1  presents more detailed  information on each of these eight
businesses.
V.    FOR FURTHER INFORMATION, PLEASE CONTACT:

            Dr.  Stephen Lai
            Singapore Institute of Standards  and Industrial Research.
            1  Science Park Drive
            Singapore,  0511
            Tel:   65-772-9548
            Fax:   65-777-1765
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      11-64

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                               Table XI-1
  SUCCESSFUL ODS ELIMINATION  IN SINGAPORE
    Name of Company
No.  of Employees
    Type  of Business
HI-P Tool & Die Ltd.
       75
Mould design &
fabrication for
injection moulded
plastic parts for
electrical industries.
Next Electronic
Technology Pte Ltd.
      303
Contract manufacturing
of PCBs, flexible
circuits, & ceramic
hybrid modules.
Mould Technic  Pte Ltd.
       56
Design & fabrication of
precision moulds and
plastic injection .
moulded parts  primarily
for medical industry.
Micro-Team Industries
Pte Ltd.
       33
Electrolysis nickel
plating of metals and
plastics,  chemical
conversion of metals, &
passivation of steels.
Jpetsu Engineering
Plastic Pte Ltd.
       15
Mould design and
'fabrication, 'precision
engineering plastic,
injection moulded parts
for audio,  computer,
electrical, &
electronic component
manufacturers.
Chartered ^Electronics
Co. Pte Ltd.
      110
Wire harnessing and
electronic parts
assembly.
Singapore Asahi
Chemical & Solder
Industries Pte Ltd.
       40
Manufacturing solder
paste, bars,  wires,
anodes, soldering
fluxes, and chemicals
for electronics
industry.
SEA Trading Company Pte
Ltd.
       38
Manufacturing
polystyrene disposable
products.
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                  11-65

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                     ELIMINATING THE USE OF ODSs IN SWEDEN
 I.     INTRODUCTION

       In  1988  the Swedish  Government,  after  consultation with industry,
 industrial  and trade  associations,  and concerned agencies,  passed a law
 mandating a complete  phaseout  of  ozone-depleting solvents (ODS)  in all end-
 uses by the end of  1995.   This was  the first complete  phaseout schedule
 proposed  worldwide.

       The task of implementing the  overall phaseout  of ODSs in Sweden was
 delegated to the Government  to the  Swedish EPA  (SNV).   In light  of the global
 nature of the  hazardous  impact of ODSs,  a vital  component of the Swedish
 strategy  was to transfer experiences from the Swedish  phaseout to other
 countries and  thus  strive  for  an  early global phase  out of ODS substances.
II.   EVALUATING ODS USE

      It was believed that although the amount of ODS used and  emitted  in
Sweden was small, and the direct impact on  improvement of the ozone  layer
would also be small, the diversity of the Swedish industrial structure  and
application areas for the CFCs was as complex as any of the larger users of
ODS.  Consequently the experience gained by Sweden from the phaseout would be
valuable to other major users.

      Of the various ODS-use areas, the solvents sector is generally
considered to be among the most sophisticated and complex.  The major users of
ODS-solvents are the electronics, telecommunications, aerospace, defense and
general engineering sub-sectors.  Consequently, ODS solvents were believed to
be difficult to replace. The Swedish Legislation called for the solvent
sector to be addressed first and mandated a 100 percent phaseout by  January 1,
1991 -- four years ahead of the national phaseout.
III.  PHASEOUT PROGRAMMES

      The SNV developed the solvent phaseout implementation programme by
cooperating with the concerned Nordic industries in a number of R&D
programmes.  These programmes called for the assessment of alternatives and
investments in some new technologies.  Two major programmes were the TRE
(Teknik f6s Ren Elektronik) and AMY (Avfetlning av Metallytor) projects.
These projects addressed alternatives and reliability issues.  The US$3.5
million programmes were co-financed by industry (e.g., electronics,
telecommunications, aerospace companies -- Ericsson, ABB, FFV, SAAB,
Electrolux, NFT, Norsk Hydro); governmental authorities (e.g., SNV (Sweden),
The Norwegian State Pollution Control Agency, The 'Danish Ministry of
Environment, The Swedish Defence Procurement Authority); research and
development institutes (IVF (Sweden), YKI (Sweden), MRI (Sweden), EC
(Denmark), VTT (Finland); industry associations (MF (Sweden); and a financial
institution (The Nordic Investment Fund).

      •The programmes were carried out with active participation of all
involved parties and began with a number of awareness workshops and


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-66

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conferences.  A hallmark of the  programmes  was  to  exclude chemical and.
equipment  supplier  financing and rely only  on industrial user and agency
financing.. It' was  the  opinion of industry  that this  approach would maintain
the integrity of  the  programme and its undertaking.

      The  programme was  initiated in 1988 and terminated in 1993.   The
activity helped contribute  in a  significant manner to the Swedish industry's
virtual 100 percent phaseout of  CFC and 1,1,1-trichloroethane use as solvent
as mandated by 1991 and  1995,  respectively.   In the case of Sweden,  only SNV
has had the authority to issue exemptions for the  use of CFC'as  a solvent
after the  phaseout  date.  As .of  January 1,  1991, exemptions had  been granted
for only a few hundred kilogrammes of CFC usage.   These  exemptions have  not
required renewal.   In the case of 1,1,1-trichloroethane,, exemptions  for  a few
hundred kilogrammes have' been submitted to  date and are  under review.  These '
exemptions, if granted are  expected to be valid only  for 1995.


IV.   INFORMATION DISSEMINATION

      A vital component  of  the phaseout strategy was  to  disseminate  the
results of the Swedish phaseout  experience  to outside parties and to work for
a more rapid global phaseout than that agreed upon by the initial Montreal
Protocol.  This effort was  executed by participation  in  the UNEP technical
assessment committees, e.g.,  the  Solvents,  Coatings,  and Adhesives Committee.
The 1989 committee  included industry and government participants from the
Canada, Japan, Sweden, Switzerland,  U.K., and U.S.  The  approach adopted for
the assessment.was  to assess all  alternatives and, on site,  examine  the
alternatives in operations  to assess the feasibility  .of  a complete phaseout
worldwide  by the  year 2000  in the  solvent sector.

      The  second  committee  was convened in  1991 and included representatives
from major chemical companies.  The mandate  for the second committee called
for a close examination  of  the .possibility  of a more  rapid phaseout  despite
the inclusion of  1,1,1-trichloroethane which at one stage was considered as  an
alternative to the  use of CFC as  a solvent.   The replacement of  1,1,1-
trichloroethane was considered especially difficult due  to its large and
diverse use.  The committee examined.alternative operations on site  for  a
variety of applications  and the conclusion  drawn by the  committee  was that,
provided sufficient funds and resources were  available,  a complete phaseout
was possible by the year 1996  with a ten-year grace period for the developing
countries.                             .
V.    FOR FURTHER INFORMATION, PLEASE CONTACT:

            Dr. Husamuddin Ahmadzai
            Naturvardsverket
            Smidesvagen 5
            S-171 85 Solna
            Sweden
            Tel:  46-8-799-11-45
            Fax:  46-8-98-99-02
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-67

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        NON-ODS  SUBSTITUTES FOR WAX  ELIMINATION AT  TOSHIBA  CORPORATION
 I.    SUMMARY

      Manufacturers have  developed vinyl-copolymer  type masking materials  that
 can be removed by hand-wiping with dry  rags  or  rags  dipped  in .organic  solvents
 such as methyl ethyl ketone  (MEK).  The use  of  these materials  can be  a
 practical "and easily-implemented  alternative to the  use of  wax  masking
 materials and ozone-depleting solvents  (ODSs) at aircraft maintenance
 facilities.
II.   INTRODUCTION

      Aircraft parts and electric  equipment parts  are  typically  covered with  a
protective mask prior  to chrome plating  to restrict  electroplating  to  the
unmasked locations on  the parts.  .At Warner Robins Air Logistic  Center's
Plating Shop, microcrystalline beeswax was used  in combination with
electroplating tape to mask parts  prior  to chrome  plating.   Before  converting
to non-ODS technology, Warner Robins removed this  wax  by placing the parts  in
a vapour degreaser after plating.  After several hours, the  heated  1,1,1-
trichloroethane vapour dissolved the wax.  The facility's  two vapour
degreasers were able to dewax approximately 500  chrome-plated parts per month.
During the process, wax would accumulate on the bottom of  the degreasers and
form a thick sludge.   The degreasers required weekly cleaning to maintain
their efficiency and to prevent accumulation of  the  wax sludge.   This  cleaning
used approximately 1,514 litres of 1,1,1-trichloroethane per week to remove
approximately 1,136 litres of sludge that was recycled at  another location  on-
site.  The use of 1,1,1-trichloroethane has been discontinued in this
application and wax is now removed from aircraft parts using steam  cabinets
equipped with numerous high pressure nozzles.
III.  THE ALTERNATIVE SELECTION PROCESS

      Electric companies have been using vinyl-copolymer  type masking
materials for years in the same application as Warner Robins.  This  type  of
material can be removed by hand easily without the use of solvents.  Some
aircraft maintenance engineers previously considered vinyl-copolymer type
materials to be less effective than wax in terms .of productivity and
reliability, especially on narrow areas or complicated surfaces.  However,
vinyl-copolymer type masking agents have been developed recently that
alleviate these concerns.

      Table XI-2 shows an example of the composition of vinyl-copolymer type
masking agents.  Many electrical engineers consider vinyl-copolymer  type
materials to be better than wax in operating characteristics, since  vinyl-
copolymer type materials can be applied with a brush or a spray and  dried at
room temperature.  Narrow areas can be coated carefully and with precision,
whereas parts must be dipped when using wax as a masking  agent.  One problem
involved in using vinyl-copolymer type materials, however, is its lower
adhesive strength.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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                  Table Xl-2
COMPOSITIONS OF VINYL-COPOLYMER-TYPE
             MASKING AGENTS
Compounds
Resin
Softener
Plasticizer
Stabilizer
Colouring Dye
Surface Lubricant
Antifoaming Agent
Solvents
Red
(Precoat: Sticky)
Vinyl chloride/
Vinyl Acetate Copolymer
DOA
(Dioctyl Adipate)
Epoxytriglycerol
Dibutylbis
.(Lauroyloxy)
stannate
Oil Red
Silicone
Silicone Type
Acetone 14-15%
MEK (Methyl Ethyl
Ketone) 30%
Methyl Isobutyl Ketone
17%
Toluene 5% .
Green (Maincoat: Normal)




Phtalocyanine Green






         * 1994 UNEP SOLVENTS. COATINGS, AND ADHESIVES REPORT *
                   11-69

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      Occasionally, vinyl-copolymer  type  films  peel off because of bubbles
generated by electrolysis,  indicating that it may be necessary to reinforce
some areas with electroplating  tape.   Another method to prevent peeling is by
.double-coating the part.  In  this  process,  a sticky precoat containing toluene
as a solvent is applied  first,  and then the main coat is applied.
IV.   CONCLUSION

      Vinyl-copolymer  type materials  should be  a convenient material to use in
masking parts prior  to chrome  plating activities.   The use of these materials
is expected to increase  as more  aircraft maintenance facilities are convinced
that vinyl-copolymer type materials will perform as well as wax in terms of
workpiece productivity and masking reliability.   It is. important to establish
evaluation methods and also  conduct additional  field testing of these masking
agents to determine  their effectiveness.
V.    FOR FURTHER INFORMATION,  PLEASE CONTACT:
/                      •

            Mr. Shigeo Matsui
            Manager  ; '
            Environmental  Protection Group  .-
            Toshiba  Corporation
            Research and Development Center
            1, Komukai Toshiba-Cho,  Saiwai-Ku
            Kawasaki, 210, Japan
            Tel:  81-44-549-2293
            Fax:  81-44-555-2074
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-70

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  USING NEW TECHNOLOGIES TO SOLVE UNIQUE PRECISION CLEANING OPERATIONS:  THE
                    ELIMINATION OF OZONE-DEPLETING SOLVENTS
               FROM THE AEROSPACE GUIDANCE AND METROLOGY CENTER
                          NEWARK AIR FORCE BASE,  OHIO
I.    INTRODUCTION

      The Aerospace Guidance and Metrology Center  (the Center) operates a
major repair facility at Ohio's Newark Air Force Base.  The Center's primary
purpose is to repair inertial guidance and navigation systems used by U.S. Air
Force aircraft and missiles.  These sophisticated  systems contain complex
electromechanical components that are extremely susceptible to contamination.
As a result, the Center operates a variety of general and precision cleaning
systems, all of which are located in strictly controlled environments.

      Prior to 1988, the Center consumed approximately 1,250 metric tons (MT)
of CFC-113 and smaller quantities of 1,1,1-trichloroethane (TCA) annually
during the precision cleaning of various electromechanical components.  Both
ozone-depleting solvents were used, to remove oil,  dirt, fingerprints, and
other contaminants deposited on electromechanical  components during their
operation and repair.
II.   AQUEOUS ALTERNATIVES

      Following the .signing of the Montreal Protocol in 1987, the Center began
its search for CFC-113 and TCA alternatives.  In order to avoid possible
future regulatory constraints, the Center sought the most environmentally
benign solution to its cleaning problem., The Center, which had access to an
inexpensive water supply and a local municipal wastewater treatment plant,
began to investigate aqueous cleaning technologies.  Aqueous detergents were
known to be environmentally friendly and are usually nontoxic or low in
toxicity.  An independent consultant hired by the Center to conduct a study of
the impacts of aqueous cleaning concluded that there would be no need for
wastewater pretreatment if the Center converted to aqueous cleaning processes.
In addition, aqueous products do not contribute to ozone-depletion or global
warming, and are not classified as volatile organic compounds (VOCs).

      Since process development began in 1987, the Center has replaced 43
percent of its ODS-based cleaning with aqueous cleaning technologies, and has
installed 17 aqueous cleaning stations, most of which include a variety of
aqueous cleaning devices.  Many of the cleaning stations contain ultrasonic
equipment, and each has access to a heated water supply and compressed-air
drying system.  To ensure consistent precision cleaning and spot-free drying,
the Center uses only high quality deionized water that is filtered and
recirculated through the deionizing system to prevent the build up of
particulate and biological film.  The water supply can be heated and delivered
to the appropriate cleaning station at.temperatures ranging from .16°C to 68°C.
The compressed air is filtered and delivered through a hand-held blowing
device at a gage pressure of 414 kPa and a flow rate of 0.0084 m3/sec.   This
method of drying parts removes moisture  in a consistent and spot-free manner
at least as rapidly as CFC-113 evaporates from the same.parts when dried in
still air.  Using this system, the Center is confident that at least 95
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 percent  of its  ODS-based cleaning methods  will  be  replaced by aqueous
 technologies  by 1995.

      The  Center scrutinizes  every aspect  of its existing cleaning me'thods to
 ensure that aqueous  alternatives  are  tailored perfectly to the application.
 Because  components repaired and cleaned by the  Center  are constructed from a
 variety  of different materials  including jewels, adhesives,  plastic,  copper,
 iron, beryllium,  and aluminum,  personnel must adjust the parameters of each
 alternative cleaning process  so that  the process satisfactorily cleans the
 specific part without  damage.   Consequently,  the aqueous detergent,  the length
 of  the drying and rinsing cycles,  the temperature  of the water,  and the design
 of  the cleaning machine  are all subject to change  from.one process to the
 next.  For this reason,  the Center develops:,each new cleaning process.
 individually.   Developing an  aqueous  method of  cleaning gyroscope  components,
 for example,  required  testing various water temperatures to ensure that the
 epoxy used to bind the gyroscope  components was not damaged during the
 cleaning process.

      The  Center  will  not convert to  aqueous  alternatives unless it is
 convinced  that  the new process  will provide a final product at least  of a
 quality  equal to  that  of the  ODS-based process  it  replaces.   Remarkably, the
 Center has found that  product quality usually increases  after converting to
 aqueous  cleaning.  Aqueous  methods of cleaning  precision bearings,  for
 example, increased their acceptable product yield  by 25  to 65 percent compared
 to  bearings cleaned  with CFC-113.   Another remarkable  trend that has  occurred
 at  the Center following  conversion to aqueous cleaning methods is  an  overall
 decrease in product  processing  times.   For example, the  total processing time
 required to clean one  of the  gyroscopes,repaired at the  Center was reduced by
 7.1 percent after switching from  CFC-113 to aqueous cleaning,  a reduction
 equivalent to 16  hours of labour.   The Center also found that aqueous cleaning
 processes  are much less  expensive  than equivalent  ODS  cleaning processes.  The
 reduction  in  CFC-113 use that has  occurred at the  Center as  a result  of its
 current  43  percent conversion.to  aqueous cleaning  is equivalent to an annual
 reduction  of  $1.8 million in  operating costs. .The investment cost for a 100
 percent  conversion to  aqueous cleaning is  not expected to exceed $1.5 million.
 Complete conversion  to aqueous  cleaning will  also  reduce' energy consumption
 and hazardous waste  disposal  at the Center.
III.  NONAQUEOUS ALTERNATIVES

      Converting ODS-based cleaning processes,to aqueous-based cleaning
processes has numerous advantages.  Unfortunately, it  is not possible  to use
aqueous processes for certain cleaning applications.   For these processes, .the
Center evaluated and selected nonaqueous alternatives  on the basis of  cleaning
performance, environmental impact, cost effectiveness, and employee health and
safety.  Using these criteria, the Center identified alcohol, volatile methyl
s'iloxanes, perfluorocarbons, and supercritical fluids  as potential nonaqueous
technoloeies that can be used to replace ODS-based cleaning processes.  These
four tec rologies have no ozone-depleting potential (OOP) and are either
nontoxic or have very low toxicity.  Each nonaqueous technology, however, has
one or m re major drawbacks.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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      Alcohol  technologies  can be used by the Center to remove mildly
activated  rosin  flux  residues  (a by-product of soldering)  deposited on fragile
gyroscope  wires.  Aqueous cleaning is  not possible  because the wires are so
fragile  that the surface  tension of water will deform them.   The primary
concern  with using  isopropyl alcohol (IPA)  is its flanunability.   For this
reason,  the Center  has  selected a cleaning system designed with safety
features that  allow its use with pure  IPA in normal production areas without
special  precautions.  IPA,  however,  is a VOC whose  emissions  are subject to
control  in many  localities. .

      The  Center is investigating .the  use of volatile methyl  siloxanes for
removing a variety  of contaminants,  including difficult-to-remove phenylmethyl
silicone which is used  as a damping fluid in some gyroscopes.   Like IPA,
methyl siloxanes are  flammable materials that require special  handling and
disposal.  Unlike IPA,  however,  methyl siloxanes are quite expensive.

      Repairing  inertial navigation systems requires extremely critical
precision  cleaning, and the Center  obtained assistance from the  Small  Business
Innovative Research Program (SBIRP)  to develop solutions to this problem.  •
SBIRP funding  is available  to  the Department of Defense (DqD)  as a means  of
encouraging small U.S.  businesses to apply  their innovative concepts to solve  '
DoD problems.  The  Phasex Corporation  was selected  to assist  in  a project
which involved the  removal  of  a heavy  phenylm'ethyl  silicone oil  from a complex
accelerometer  assembly.  The assembly  must  be cleaned in one piece,  which is
difficult  to achieve  with CFC-113 and  impossible to achieve with an aqueous
proce3s.   Phasex considered both carbon dioxide and ethane as  part of  a
supercritical  fluid (SCF) cleaning  process  to remove silicone  oil from the
assembly.  After,thorough research  and testing, ethane was found to be
superior to carbon  dioxide  as  a supercritical solvent for  removing the oil.
Although ethane  is  flammable,  it, unlike carbon dioxide, has no  global warming
potential.   In general, SCF technology is effective at removing  oil and grease
from components  or  assemblies  whose  parts are not harmed by temperature and
pressure applied during the process.   Phasex,  working with process experts at
the Center, designed  and constructed a SCF  cleaning station which can  operate
with either carbon  dioxide  or  ethane.   The  cleaning delivers a superb  product,
but will not be  used  for applications  which can be  performed with cheaper or
more environmentally  benign technologies.

      A  second SBIRP  project was  aimed at developing a perfluorocarbon
technology for the  removal  of  fluorinated oil and particulate  from inertial
components.  Entropic Systems  was selected  to lead  the project;,  and developed
an ultrasonic  process that  uses  a perfluorocarbon with a fluorinated
surfactant for cleaning.  The  process  removes particulates better than CFC-
113, and has been incorporated into  a  low-emission  cleaning station that  began
operation  in 1994.  Because of the high cost and high global warming potential
of perfluorocarbons,  the Center  plans  to use the new technology  only when
other alternatives  are  not  capable  of  achieving the desired level of
cleanliness.                                       •  •           •
                    * 1994 UNEP SOLVENTS. COATINGS, AND ADHESIVES REPORT *
                                     11-73

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IV.   CONCLUSION

      Through the extensive  research,  development, and implementation of
alternative manufacturing  and cleaning methods,  the Aerospace Guidance and
Metrology Center has dramatically reduced its use of CFC-113 and TCA in the
last five years.  The  Center plans to  continue reducing its use of ozone-
depleting solvents to  achieve a complete phaseout in early 1995.
V.    FOR FURTHER INFORMATION,  PLEASE CONTACT:

            Don E. Hunt
            Chief Scientist
            AGMC/CN
            813 Irving-Wick  Drive.,  W
            Newark Air Force Base
            Newark, OH 43057-Q013
            USA
            Tel:  1-614-522-7712
            Fax:  1-614-522-7449
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-74

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          Case Study: Vibro-Meter SA, Villars-sur-Glgne,  Switzerland
I.    INTRODUCTION       .                                                  .

      Vibro-Meter SA  is  a manufacturer of vibration  detectors  for  gas  turbines
and similar applications, as well as  sensors  for pressure,  flow  etc.   They
also design and manufacture the associated electronics  for  these sensors.
Because its products  are used extensively in  the aerospace  industry, high-
reliability is a requirement for all  finished products.

      The electronics assemblies use  conventional, surface-mount,  and  mixed
technologies with small  physical dimensions and high component densities on
multi-layer boards.   Prior to 1992, wave-soldering was  performed exclusively
with a medium-solids  RA  flux and reflow  soldering used  an RMA  solder-paste.
The cleaning process  used a CFC-113/alcohol azeotrope in an open-top manual
vapour phase degreaser with water-cooling and two solvent tanks.   Initially,
no specific precautions were taken to minimise solvent  vapour  emissions.
Therefore, the solvent consumption per unit area of  cleaned boards was
relatively high, especially considering  that  the production rate was moderate
and inc ons i s tent.

      In early 1992,  it was realised  that the Swiss  Federal Ordinance  on
Substances Dangerous  to  the Environment was legislating a phase  out of the use
of CFC-113 and 1,1,1-trichloroethane  for industrial  purposes by  December 31,
1992. .              •
II.   THE SEARCH FOR A SUBSTITUTE

      A study of substitute processes  (materials.and equipment) was undertaken
and it became apparent that all the technically and economically viable
cleaning methods used water, at least  in the final-phase of cleaning. 'Given
the stringent regulations on heavy metals,  ( 0.1 mg/1 for lead, 1 mg/1 for
copper, and 2 mg/1 for tin ) in water  quality in the Swiss Federal Ordinance
on the Discharge of Waste Waters, the  prospect of using water  in the cleaning
process was not initially attractive.  In addition, the Cantonal (State)
authorities wished to apply Federal recommendations for pH and BOD5 to the
wastewater.  As the production level at the Vibro-Meter facility was fairly
small, a capital-intensive or consumable-intensive wastewater  treatment plant
could not be justified.

      After a quick examination of the possible alternatives,  the list was
narrowed to the following:

      •     "No-clean" soldering                           .        .
      •     Water-soluble flux with aqueous-cleaning
      •     Sappnification-removal of  rosin fluxes, plus aqueous cleaning
      •     Hydrocarbon/surfactant removal of rosin fluxes, plus aqueous
            cleaning

      "No-clean" techniques were rejected because of worries about consistency
in process control and materials..  An  examination of available machinery for
aqueous cleaning revealed that there were three types readily  available:  a
modified 'dishwasher', type which could have limited throughput and relatively


                    * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                                     11-75

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 high water  and energy consumption;  a 'high-throughput'  batch machine;  and a
 number  of conveyorised "in-line"  machines.
 Ill.  AQUEOUS  CLEANING  OF PRINTED CIRCUIT BOARDS .

      One  'high-throughput'  batch machine vendor offered a solution which
 satisfied  all  of  the  company's  requirements  in terms  of capacity,  technical
 feasibility, and  water  and energy consumption.  With  the assistance of
 information  from  the  vendor,  this system was accepted by the  authorities on
 condition  that analyses taken at  the  outfall showed acceptable pollutant
 levels according  to Federal and Cantonal regulations.   The only exception
 allowed by the authorities was  for the  stainless steel machine to  be cleaned
 periodically with a short-chain linear  carboxylic  acid product whose working
 solution could have a pH lower  than the permitted  limit of 6.   This cleaning
 process involved  a maximum of 50  litres of solution once per  month.

      The  system  has  a  "hold tank" after soldering with a water-soluble  flux
 or paste.  All the assemblies coming  out of  the wave-soldering machine or the
 reflow oven  were  immediately placed in  a polyethylene  tank containing a  weak
 aqueous chelating solution.   This room-temperature solution removed most of
 the residues from the warm assembly while they .were still liquid and took them
 into solution.  The slight alkalinity of the solution  (pH about 9)  also,
 prevented  the  highly  acidic flux  residues from attacking the  solder surface,
 ensuring an  easily inspectable  solder joint.   In addition,  the chelating
 action solubilised the  heavy metal salts resulting from the reaction between
 the flux and the  metal  oxides on  the  solder  surface or the component leads.
 Foam reduction was yet  another  advantage of  the process.   The  result of  the
 "hold tank" was that  less  than  5-10%  of the  normal amount of  contaminants were
 present after  the  solution left the tank.  The water  in the "hold  tank"  is
 tested by  a  dye which changes colour  if the  pH drops excessively and by  a
visible precipitation if the heavy metal content exceeds the  chelating power
 of the solution.                                      '

      The  cleaning machine has  a  50 litre tank which  is .initially  filled with
 tap or deionised water.  A high-power pump sprays  the  water onto the
 assemblies, which  are held near-vertically in baskets,  via jets from linearly
 oscillating  spray  bars  held above and below  the parts.  After  the wash cycle,
 the boards are  sprayed  in  open  circuit  with  deionised  water.   This  water may
have 3-5%  isopropanol added.  The rinse  spray bars are separate from the wash
 spray bars.  The oscillation of the spray bars ensures approximately eight  to
 ten separate spray rinses  at  any  given  point on an assembly during  the 30-45
 second rinse period.   The  rinse water is uncontaminated when  it initially
reaches the assemblies.  After  the rinse cycle, the lightly contaminated rinse
water falls  into the wash-water tank  a'nd dilutes the contents.  Wash water  is
normally only.'drained at  the  end  of each week.

      Once rinsed, the  baskets  are transferred into an separate drying
machine.   The  drying machine  utilizes very-high-speed  rotary  air knives  which
mechanically blow  off the  excess  water  and contaminants (approximately 90-95%
of the quantity at the  cleaning machine  exit) within a few seconds.   The
resi'dual moisture  is  then  evaporated, requiring comparatively  little energy.
It is possible  to  clean and dry a basket with 1-2  nr of assemblies every 6-8
minutes.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHES1VES REPORT *
                                     11-76

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      The residues from the new cleaning system have been  shown by
Contaminometer tests to be better than  /s-1/io °f t^e  residue  levels  from the
previously used CFC-113 cleaning system, and well under  the  limits  specified
by military standards.  The only negative aspect that  has  arisen  is the  need
to be more careful about selecting components with  the cleaning process  in
mind.  Although an adaptation period was needed to  achieve optimum
performance, the use of water-soluble chemicals has made the soldering process
marginally better, resulting in a small reduction in the amount of  rework
required.

      No significant problems have arisen as a result  of wastewater
generation.  The contents of the hold-tank are drummed disposed of  as a
special hazardous waste after the tank is emptied periodically.   The  .costs -of
treating a lightly basic aqueous solution with heavy metals  are relatively
small.

      The company has found that the equipment selected  is particularly
economical in terms of both deionised water and energy use with no  overall
cost increase compared to CFC-113.  Typical consumption  is 5 litres and
700 kWh per square metre of assemblies, respectively.
IV.   CONCLUSIONS

      This case study provides an example  of  the  defluxing  of high-reliability
assemblies in a small-to-medium  sized  enterprise,  respecting  all  the
environmental criteria in a.country noted  for severe  restrictions.  The  same
techniques may be applied in both developing  and  developed  nations.   The
capital cost required for the conversion is approximately US$40,000.
V.    FOR FURTHER INFORMATION,  PLEASE  CONTACT:

            Monsieur A. Blanc
            Vibro-Meter S.A,
            route de Moncor
            CH-1701 Fribourg
            Switzerland
            Tel:  41-37-87-11-11
            Fax:  41-37-87-16-59
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     11-77

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                            APPENDIX A

       Members of the UNEP Solvents, Coatings and Adhesives
       Technical Options Committee for Technical. Assessment
             Under Article 6 of the Montreal Protocol
Dr. Husamuddin Ahmadzai
Swedish Environmental
Protection Agency
STATENS NATURVARDSVERK
S-171 85 SOLNA
Sweden
Phone:  46 8  799 1145
Fax:  46 8 989 902

Mr. Lorenzo Alvarez
SAEO South America Electronics
Operation
Av. Orlanda Bergamo, 1000
Bairro Industrial de Cumbica-
Guarulhos •
Sao 'Paulo
Brazil
Phone:  55 11 945 9367
Fax:  55 11 945 9160

Dr. Stephen 0. Andersen
Deputy Director
Stratospheric Protection
Division  .           ,
U.S. Environmental Protection
Agency
Mail Code 6205J
401 M Street, SW       •  • '
Washington, DC 20009
Phone:  1 202 233 9069
Fax:  1 202 233 9576

Dr. David Andrews
GEC-Marconi
Hirst Research Centre
Elstree Way
Borehamwood
Herts WD6^1RX
United Kingdom
Phone:  44 81 953 2030
Fax:  44 81 732 0340
Chapter Committees

Electronics Cleaning;
Precision Cleaning; Metal
Cleaning; Dry Cleaning;
Adhesives; Aerosol Products;
Other Uses
TOC Committee Chair
Precision Cleaning
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                A-l.

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Mr. Jay Baker
Ford Electronics Technical
Center
Room C290
17000 Rotunda Drive
Dearborn, MI 48121
Phone:  1 313 845 3597
Fax:  1. 313 323 8295   .

Mr. Bryan Baxter
#30   '
The Avenue
Hitchin
Hertfordshire SG4 9RJ
United Kingdom
Phone:  44 462 455 379
Fax:  44 462 456 775

Mr. Charles Carpenter
Waste -Policy Institute
PO Box 35399
Brooks AFB, TX 78235-5399
Phone:  1 210 534 8012
Fax:  1 210 536 2069

Mr. Pakasit Chanvinij
Thai Airways International
Ltd.
Bangkok Airport
Don Muang
Thailand
Phone:  662 531 1955 64  ext.
1185
Fax:  662 533 6288

Mr. Mike Clark
Sketchley Dry Cleaners
PO Box 7
Hinckley
Leicestershire LE10 2NE
United Kingdom
Phone: ' 44 455 238 133
Fax:  44 455 619 056

Mr. Jorge Corona
Environmental Commission
Cto. Misioneros G-8, dep. 501
Cd. Satelite
53100, Edo de Mex.
Mexico
Phone:  52 5 393 3649 /  399
9130
Fax:  52 5 572 9346
Electronics Cleaning
Chair - Precision Cleaning;
Other Uses
Metal Cleaning; Adhesives;
Coatings and Inks
Metal Cleaning; Precision
Cleaning
Chair - Dry Cleaning
TOC Committee Vice Chair,
Chair - Aerosol Products
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                A-2  '

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Mr. Brian Ellis
Protonique S.A.
PO Box 78
CH-1032 Romanel-sur-Lausarine
Switzerland
Phone:  41 21  648  2334
Fax: • 41 21  648'  2411

Mr. Stephen  Evanoff
Lockheed Environmental
980. Kelly Johnson  Dr.
Las Vegas, NV  89119
Phone:  1 702  897  3228
Fax:  1 702  897  6645    •  '

Mr. Joe R. Felty
Texas Instruments  Incorporated
MS 8013
2501 W. University
McKinney, TX 75070
Phone:  1 214  952  5318
Fax:  1 214.952  2568

Dr. John Fisher
AT&T Bell Laboratories
PO Box 900
Princeton, NJ  08542-0900
Phone:  1 609  639  2219
Fax:  1 609  639  2835

Mr. Art FitzGerald
IFC
3187 Barwell Rd.
Mississauga, Ontario L5L  3Z6
Canada
Phone:  1 905  569  2733
Fax:  1 905  569  2733
 Chair  -  Electronics Cleaning
 Chair  - Metal  Cleaning;
 Adhesives; ;Coatings  and  Inks
Electronics  Cleaning; ••      .   '
Precision  Cleaning;  Othe.r JJses
Alternate  for Dr.  Leslie  Guth
.Chair  - Coatings  and  Inks
Ms. Pamela Foster
Friends of the Earth
701-251 Laurier Avenue  West
Ottawa, Ontario KIP 5J6
Canada
Phone:  1 613 230  3352
Fax:  1 613 232 4354

Mr. Yuichi Fujimoto
JEMA
4-15, Nagata-cho 2-chome
Chiyoda-Ku
Tokyo 100
Japan
Phone:  81 3 3581  4845
Fax:  81 3 3506 0475
Electronics  Cleaning;
Precision Cleaning;  also
Senior Advisor  TEAP
                  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                                A-3

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 Ing.  G.  Gabelmann
 ITT Teves  GmbH
 Guerickestr.  7
 6000  Frankfurt/M.  90
 Federal  Republic of Germany.
 Phone:   49 69 76 03 2878
 Fax:  49 69  76 10 61

 Dr. Leslie Guth
 AT&T  Bell  Laboratories
 PO Box 900
 Princeton,  NJ .08542-0900
 Phone:   1  609 639 3040
 Fax:  1  609  639 2851

 Mr. Don  E.  Hunt
 United States Air Force
 AGMC/CN
 813,Irvingwick Dr.  West
 Newark AFB,  OH 43057-0013
 Phone:   1  614 522 7712
 Fax:  1  614  522 7449

 Mr. Yoshiyuki Ishii
 Senior Engineer
 Environment  Policy Office
 Hitachi  Ltd.
 New Marunouchi Bldg.
 5 -1,  Marunouchi 1-chome,
 Chiyoda-ku
•Tokyo 100
 Japan
 Phone:   81
 2722
 Fax:  81 3  3214 3545
                        Electronics  Cleaning;
                        Precision Cleaning
                        Electronics  Cleaning
                        Precision  Cleaning
                        Metal Cleaning;  Precision
                        Cleaning
3 3212 llll ext.
Mr. Peter G. Johnson
European Chlorinated Solvent
Assoc.
Avenue E. Van Nieuwenhuyse 4,
box 2
B-1160 Brussels
Belgium
Phone:  32 2 676  72  63
Fax:  32 2 676 72  41

Dr. William'G. Kenyon
Global Centre for  Process
Change
PO Box 553
Montchanin, DE 19710-0553
Phone:  1 302 652  5597
Fax:  1 302 652 5701
                        Metai; Other Uses
                        Electronics  Cleaning;  Metal
                        Cleaning; Other  Uses
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                A-4

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 Mr. Sudhakar Kesavan
 ICF Incorporated
 Suite 1000
 1850 K Street, NW
 Washington, DC 20006        .  -
 Phone:  1 202 862 1140
 Fax:  1 202 862 1144

 Mr. Hiroshi Kurita
 Japan Association for Hygiene
 of Chlorinated Solvents
 (JAHCS)
 Hongoh-wakai Building
 40-17 Hongoh 2-Chome
 Bunkyo-ku, Tokyo 113
 Japan
.Phone:  81 3 3814 3411/3412
 Fax:•  81 3 3814 3413

 Dr. Steve Lai
 Singapore Institute of
 Standards and Industrial
 Research  (SISIR)
 l  Science Park Drive .
 Singapore.0511
 Phone:  65 772 9548
 Fax:  65 777 1765

 Mr. Leo Lambert
 Digital Equipment Corporation
 200 .Forest Street
 Marlboro,  MA 01752
 Phone:  1 508 467 3647
 Fax:  1 508 467 1300

 Mr. Milton E. Lubraico
 Ford Industria e Caomercio
•Av. Orlanda Bergamo, 1000
 Bairro Industrial .de Cumbica -
 Guarulhos
 Sao Paulo
 Brazil 07200
 Phone:  55 11 753 4665
 Fax:  55 11 945 9110 4671

 Dr. Mohinder P. Malik
 Manager, Materials and Process
 Technology
 Lufthansa German Airlines
 Postfach 630300
 D-22313  Hamburg
 Germany
 Phone:  49 40 50 70 2139
 Fax:  49 40 50 70 1397
Chair - Other Uses; Dry
Cleaning; Adhesives; Aerosol
Products
Chair - Laboratory Uses;
Precision Cleaning; Metal
Cleaning
Electronics Cleaning;
Precision Cleaning
Electronics Cleaning
Metal Cleaning; Precision
Cleaning
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                A-5

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Mr. Shigeo Matsui
Manager
Japan Audit and  Certification
Organization Ltd.
Hoshigaoka Building  2F
2-11-2 Nagata-cho  Chiyoda-ku
Tokyo
100 Japan
Phone:  81 3 3503  8021
Fax:  81 3 3506  0475

Ms. Annie Maurel-Groleau
TELEMECANIQUE '
43-45 Boulevard  Franklin
Roosevelt
B.BP. 236
92*504 Rubil-Malmaison
Cedex
France
Phone:  33 1 45  69 22 22
Fax:  33 1 45 69 20  76

Mr. James A. Mertens
Dow Chemical
Advanced Cleaning  Systems
2020 Dow Center
Midland, MI 48674
Phone:  1 517 63€  8325
Fax:  1 517 636  8933

Mr. Hank Osterman
Allied Signal, Inc.
Fluorocarbons                 •
Nichols 5
PO Box 1139
101 Columbia Rd.
Morristown, NJ 07962-1053
Phone:  1 201 455  4551-
Fax:  1 201 455  2745/2615

Mr. Fritz Powolny
OXITENO
Av. Brig Luis Antonio
1343 10 Ampar
Sao Paul SP
Brazil
Phone:  55 11 283  6106/6044
Fax:  55 11 284  2501

Ms. Cynthia Pruett
12592 Daffodil Drive
Mariassas, VA 22111-4644
Phone:  1 703 367  1019
Fax:  1 703 .367  2319
Electronics Cleaning;
Precision Cleaning;  Metal
Cleaning
Electronics Cleaning; Metal
Cleaning; Dry Cleaning;
Adhesives; Aerosol Products,-
Other Uses
Chair - TEWI; Metal Cleaning
Metal Cleaning; Drecision
Cleaning
Electronics Cleaning
                  1994 UNEP SOLVENTS,-COATINGS, AND ADHESIVES REPORT •

                                A-6

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Mr.  Patrice Rollet
Promosol
26,  Avenue  de  Petit  Pare
94683  Vincennes  Cedex
France
Phone: l 33  1 43  98 75 00
Fax:   33  1  43  98 21  51
             /

Ing. Wolf-Eberhard Schiegl
Siemens AG         '
ZPL  r  ZUWS
Otto-Hahn-.Ring 6
8-1730 Munchen
Federal Republic of  Germany
Phone:  49  89  636 40165
Fax:   49  89 636  40162
  *    - v

Mr.  Hussein Shafa'amri
PO Box 555
Amman
Jordan
Phone:  962 66 444 66
Fax:   962 66 493 41
                             »
.Lt.  Col. John  Shirtz
Space  and Missile Systems
Center/SDZ
2435 Vela. Way
Suite  2218
Los Angeles AFB,  CA  90245-5500
Phone:  1 301  363 0010
Fax:   1 301 363  6439

Mr. Barrel  A.  Staley
Boeing Defense & Space Group
MS 89-18
PO Box 3999
Seattle, WA 98124-2499
Phone:. 1 206  773 0046
Fax:   1 206 773  2432

Dr. John R.  Stemniski
Charles Stark  Draper
Laboratory
555 Technology Square
Cambridge,  MA  02139-3563
Phone:  I 617  258 4265
Fax:   1 617 258  1131
 Metal  Cleaning;  Other Uses
 Electronics  Cleaning;
 Precision  Cleaning
.Chair  - Rocket Applications;;
 Precision  Cleaning;  Other  Uses
Metal Cleaning;  Precision
Cleaning
Precision Cleaning; Metal
Cleaning; Adhesives;  Coatings
and Inks           ""
                  1994 UHEP SOLVENTS, COATINGS. AND ADHESIVES REPORT

                                A - 7

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Lt. Col. Doug van  Mullem
United States Air  Force
Space and Missile  Systems
Center/CV
2430 E. El Segundo Blvd.,
Suite 6037
Los Angeles AFB, CA 90245-4689
Phone:  1 310 363  0013 '
Fax:  1 310 363  1256

Mr. John Wilkinson
Vulcan .Materials Co.
Chemicals.Division
1899 L Street, NW
Suite 500
Washington, DC 20036
Phone:  1 202 293  0635
Fax:  1 202 659  3119

Mr. Masaaki Yamabe
Asahi Glass Co., Ltd.
1150 Hazawa-cho, Kanagawa-ku
Yokohama 221
Japan
Phone:  81 45 334  6111
Fax:  81 45 334  6023

Mr. X'Avier Hk Yoong
National Semiconductor  Sdn Bhd
Bayan Lepas Free Trade  Zone
11900 Penang
Malaysia
Phone:  60 483 7211
Fax:  60 483 3894
Alternate for Lt.
Shirtz
Col.  John
Metal Cleaning; Adhesives;
Coatings and 'Inks  >•
Electronics Cleaning;
Precision Cleaning; Metal
Cleaning
                 * 1994 UNEP SOLVENTS, COATINGS. AND ADHESIVES REPORT *
                                A-8

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                            APPENDIX B

  Expert Advisors to the UNEP  Solvents.  Coatings and Adhesives
                   Technical Options  Committee
Mr. Wayne Bishop
MR&D Engineer
Boeing Commercial Airplane Group
PO Box 3707   .
MS:  97-39
Seattle, WA 98124-2207
Tel:  206-237-8168
Mr. Bill Brox
IVF
Molndalsvagen 85, S-412  85
Goteborg, Sweden
Mr. Shigeru Dejima
Deputy Division Manager, Fabricare  Research  Center
All Japan Laundry & Drycleaning Association
472 Akiba-cho, Totsuka-ku, Yokohama-shi
Kanagawa-ken 245
Japan                 ...          .
Tel:  81-45-811-3639
Fax:  81-45-812-5176
Mr. Joseph M. Fletcher
MR&D Engineer     .     ,   -
Boeing Commercial Airplane Group
PO Box 3707
MS:  97-29
Seattle, WA 98124-2207
Tel:  206-237-5992
Fax:  206-237-1465
Mr. Rick Freeman
Chemical Engineer
Boeing Commercial Airplane  Group
PO Box 3707
M.S. 5H-23
Seattle, WA  98124-2207
Tel:  206-931-5098  -
Fax:  206-931-2815
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                B-l

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Dr. Johnny  L.  Golden
Senior Specialist  Engineer
Boeing Defense and Space Group
PO Box 3707
MS:   82-32
Seattle, WA 98124-2207
Tel:  206-773-2055
Fax:  206-773-4946

Mr. Gene Green
MR&D  Factory Support Lead
Boeing Commercial  Airplane Group
PO Box 3707
MS:   99-39
Seattle, WA 98124-2207
Tel:  206-237-3310
Fax:  206-237-4509
Mr. Michael  Hall
Environmental  Unit  IB
Desk  3/043
Department of  Trade and Industry
151 Buckingham Palace Road
London SW1W  9SS
United Kingdom
Dr. Kevin Joback
Molecular Knowledge  Systems
26-452 Kessler  Farm  Dr.
Nashua, NH  03063
Tel:  603-881-9821
Mr. Thomas Jones,
Research Engineer
Boeing Commercial  Airplane Group
PO Box 3707
M.S.  5H-23
Seattle, WA  98124-2207
Tel:  206-931-5914 -.
Fax:  206-931-2815
Dr. Karla Karash
EG&G Dynatrend
21 Cabot Rd.
Woburn, MA 01801
Tel:  617-935-3960
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                B-2

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Mr. Robert A.  Kisch,  P.E.
Specialist Engineer
Boeing Commercial Airplane Group
PO Box 3707
MS:  5H-23
Seattle, WA  98124-2207
Tel:  206-931-2106
Fax:  206-931-2815
Mr. Toshihide  Kita
General Manager,  Technical  Department
Japan Association for Hygiene of  Chlorinated Solvents
40-17, Hongo 2-chome,  Bunkyo-ku
Tokyo 113
Japan
Tel:.  81-3-3814-3412
Fax:  81-3-3814-3413
Mr. Kenroh  Kitamura
Research Center
Asahi Glass Co.,  Ltd.
1150 Hazawa-Cho  Kanagawa-Ku
Yokohama City
221 Japan
Tel:  +81 45 334  6137
Fax:  +81 45 334  6187
Mr. Ronald Kuse
MR&D Engineer
Boeing Commercial Airplane  Group
P.O. Box 3707
M.S. 97-29
Seattle, WA  98124-2207
Tel: 206-237-1505
Fax: 206-237-1465
Mr. Bud Levine
Vice President
Deft, Chemical  Coatings
17451 Von Karman  St.
Irvine, CA  92714
Tel: 714-474-0400
Fax:
Mr. Bjorn Lindstrom
Ericsson Radar  Electronics  AB
Bergfotsgatan 2,  S-431  84
Molndal, Sweden
Tel:.46-31-67-1000
'Fax: 46-31-87-6639
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                B-3

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Mr. Nigel  S.  Lo
Senior  Specialist  Engineer
Boeing  Commercial  Airplane Group
PO Box  3707
MS:  5H-23
Seattle, WA   98124-2207
Tel:  206-931-5090
Fax:  206-931-2815

Dr. Peter  G.  Miasek
Market  Development Account Executive
Performance Products  Group
Exxon Chemical  Canada
P.O. Box 4029,  Station 'A'
Toronto, Ontario   M5W 1K3
Canada
Tel: 416-733-5310
Fax:
Mr. Shinsuke Morikawa
Research Center
Asahi Glass Co.,  Ltd.
1150 Hazawa-Cho  Kanagawa-Ku
Yokohama City
221 Japan
Tel:  +81 45 334  '6137
Fax:  +81 45 334  6187
Mr. Robert H. Norris
Technology Transfer Manager,  Adhesive Systems
3M Industrial Specialties  Division
3M Center Bldg. 209-IN-18
St. Paul, MN  55144-1000
Tel: 612-736-8236
Fax: 612-733-4457
Mr. Michael C. Oborny
Cleaning and Contamination  Control  Division 1834
Sandia National Laboratories
Albuquerque, NM  87185-5800
Tel: 505-845-8040
Fax: 505-844-1543
Mr. Donald Peterson
Lead Engineer Wing Line Support
Boeing Commercial Airplane Group
PO Box 3707
MS:  92-07
Seattle, WA  98124-2207
Tel:  206-237-7015
Fax:  206-237-4604
                 * 1994 UNEP SOLVENTS-, COATINGS, AND ADHESIVES REPORT
                                B-4

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Dr. Hans  K.  Pulker
Director  -  Central Research Laboratory
Balzers Ltd.
FL-9496 Balzers,  Liechtenstein
Tel: 075 .4  41-11/4.4396
Fax: 075  4  27  61
Ms. JoAnn A.  Quitmeyer
Research Associate,  Metalworking Fluids
Dewey and Almy  Chemical  Division
W.R. Grace  &  Co.  -  Conn.
55 Hayden Ave.
Lexington,  MA  02173
Tel: 617-861-6600
Fax:
Mr. Alan Robinson
Lead MR&D Engineer,  Retired
Boeing Commercial Airplane  Group
c/o Mr. Ronald  Kuse
The Boeing Co.
P.O. Box 3707
M.S. 97-29
Seattle, WA  98124-2207
Tel: 206-237^1505
Fax: 206-237-1465
Mr. Joel E; Rodgers
Vice President
Genesolv/Baron-Blakeslee
Allied-Signal,  Inc.
Engineered Solvent Systems
P.O. Box 1139R
101 Columbia Road
Solvay-5
Morristown, NJ   07962
Mr. Dave Smukowski
Senior Manager of Environmental  Operations
The Boeing Co.
P.O. Box 3707
M.S. 7E-EH
Seattle,. WA  98124-2207
Tel: 206-393-4782
Fax: 206-393-4718
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                B-5

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Dr. Donald R.  Theissen
Director
3M Corporate  Product  Responsibility
3M Center Bldg.  225-3N-09
St. Paul, MN   55144-1000
Tel: 612-733-6050
Fax:
Mr. John Vakiner
Optics Process  Engineer
Texas Instruments  Incorporated
Box 660246, M/S 3189
Dallas, TX  75243
Tel: 214-480-4552
Mr. Pei Wang
Semiconductor  Group
Texas Instruments  Incorporated
Box 665012, M/S  944
Dallas, TX  75265
Tel: 214-997-3268
Mr. Raymond Watkins
Functional Test  Electrician
Boeing Commercial Airplane Group
P.O. Box 3707
M.S. 00-56
Seattle, WA  98124-2207
Tel:'  206 342  4839
Dr. Jorg Wullschleger
President, CEO
Leica Heerbrugg  Ltd.
CH-9435
Heerbrugg, Switzerland
Tel: 071 703  857/703 131
Fax: 071 703  018
Mr. Shun-ichi Yamashita
Chiefr Technical Department
Kanto Denka Kogyo  Co., Ltd.
Tokio Kaijo Bldg.  Shinkan llth Floor
1-2-1, Marunouchi,  Chiyoda-ku,  Tokyo 100,
Japan
Tel:  81-3-3216-4562
Fax:  81-3-3216-4581
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                B-6

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Mr. Dennis Zupan
Technical  Supervisor
Brulin  & Company, Inc.
P.O. Box 270-B
2920 Dr. Andrew J. Brown Ave.
Indianapolis,  IN  46206
Tel: Inside Indiana 1-800-423-0962
     Toll  Free 1-800-428-7149
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                 B-7

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                                  APPENDIX C1
              RECOMMENDED GUIDELINES AND  CONTROL ACHIEVABLE WITH
                      BEST AVAILABLE TECHNOLOGY (BAT) FOR
            VOLATILE ORGANIC COMPOUND  (VOC)  SOLVENT-BASED  CLEANING
I.    GENERAL

      Solvent losses are often very  great  in, a  conventional  or  poorly
maintained plant.  In a(poorly maintained  plant,  only  about  20  percent  of the
purchased solvent quantity  is generally  recovered (Figure  C-l).

      Numerous solvent blends are used in  the industry and accordingly,  not
all are equally recoverable.  Table  C-l  compares  some  CFC-113 based solvents
for conventional recovery.

      Depending on what measures have already been adopted at,a facility,
application of the guidelines summarized below  can enable  total emissions to
be reduced by 90 percent.   Solvent losses  can be  reduced from 2-5  kg/h-m2 of
bath area with conventional practice to  0.2  - 0.5 kg/h-m2  of bath  area..   For
certain alcohol based and partially  aqueous  systems, the overall base rate of
annual losses is around 0.03 - 0.05  kg/h,m2 of bath area (Ahmadzai,  1991a).
The guidelines are concerned with the best available technology for the
following:  '                                                               .

      •     cold cleaning
      •.    vapour cleaning (including equipment  with  spray/ultrasound)
      •     continuous  "in-line" cleaning.

      Table C-2 lists several VOCs and classifies them according to their
importance in episodic ozone formation.
II.   DESIGN OF THE CLEANING EQUIPMENT

      1.    Cover

      For processes where:

      •     the solvent has a vapour pressure >  2 kPa  (15 mm  Hg)  at  38°C
            (e.g:, all halogenated  solvents), or

      •     the solvent is heated,  or                         .

      •     the solvent is agitated mechanically, or

      •     where the equipment's opening  is > 1.0 m2,
     1   The information presented in this appendix was provided by Dr.
Husamuddin Ahmadzai.

                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      C-l

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                                     Figure C-l

                     SOLVENT LOST IN A TYPICAL PLANT
Solvent
                                      Evaporative Losses,
                                      Seals, etc.    12%
             Drag Out    Evaporative Losses,
             40%        Seals, etc.   2%
                    Evaporative Losses
                          1%
            Holding
            Tanks
             3%
         Spills, Leaks
  18%
Recycle
  Hand
Cleaning
                                                               15% Evaporative Losses
                    *
                    H
                                             UJ

                                             I'
                                                                                           o
Source: Northern Telecom. 1989 CFC Program.

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                Table C-l.  COMPARISON OF RECOVERABILITY BETWEEN
                             CFC-113 SOLVENT GRADES
            Grade
        Major Use
 Recoverability
In-House (Yield)
.Straight CFC-113
Azeotropes

   CFC-113/alcohols
   CFC-113/acetone
   CFC-113/MC

Non-Azeotropes

   CFC-113/high'bp alcohols
   CFC-113/low bp alcohols
   CFC-113/water emulsions

   CFC-113/displacement
    surfactants
   CFC-113/lubricant
Vapour cleaning of, plastic/         High
metals/glass
Flux removal                        High
Vapour cleaning of plastics         High
Vapour cleaning of metals           High
Flux removal                        High
Flux removal          '              Low
Precision cleaning and              Low
drying
Drying                              High

Metal working  (e.g., riveting)      Zero
 Source:   Adapted from Clementson 1988c.
                     * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       C-3

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                    Table C-2.   CLASSIFICATION OF VOCs
More important

Alkenes
Aromatics
Alkanes
Aldehydes
Biogenics

Less important

Alkanes
Ketones
ketone
Alcohols
Esters

Least important

Alkanes
Alkynes
Aromatics
Aldehydes
Ketones
Alcohols
Esters
Chlorinated hydrocarbons
 > C6 alkanes except 2,3 dimethylpentane
 All aldehydes and benzaldehyde "
 Isoprene
 C3 -  C5 alkanes and 2,3 dimethylpentane
•Methyl ethyl ketone and methyl t-butyl

 Ethanol
 All esters except methyl acetate
 Methane and ethane
 Acetylene
 Benzene
 Benzaldehyde
 Acetone
 Methanol
 Methyl acetate
 Methyl chloroform,
 Methylene chloride,
 Trichloroethylene and tetrachloroethylene
                  * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT.*
                                    C-4

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it should be possible to operate the cover  automatically  or with minimal
effort.  Cover design (e.g., horizontally sliding action)  should permit
operation that does not create turbulence in  the vapour zone  (e.g.,  avoid
flip-open type design).  The equipment  should be designed so  that  the  cover(s)
opens and closes only during charging or discharging of the workload (e.g.,
air lock). •

      2.     Arrangement for Drainage of Cleaned Components

      For solvents with a vapour pressure > 2 kPa (at  30  mm Hg, 38°C),
drainage 'should take place inside the machine with  the cover  closed.

      3.     Safety Devices

      To prevent solvent evaporation during equipment  stoppages, the following
safety devices should be 'installed:

            •     Monitors and thermostats  to check the flow  of liquid to the
                  condenser and heating element (<  18°C)  and  an equipment shut
                  off'in the event of a circulation stoppage  or overheating.
                                     t
            •   -  Spray monitor that shuts  off the  spray  device, if the vapour
                  level drops 10 cm.

      4.     Operating Instructions Should be  Posed  Visibly and Should
            Summarize All Operating Steps

      5.     Design of -Solvent Spray

      To cpnserve solvent, the spray should be of the  continuous type  (not
atomizing).   The nozzle pressure should be  regulated so it does not  give  rise
to excessive splatter, _and where applicable,  be applied under the vapour
level.

      6.     Design of Work Load Carrier

      Components should be fed in automatically.  The  design  of the  work  load
carrier should facilitate drainage and  not  cause a  "piston effect."  A hook
arrangement is preferable.
                 /
      7.     For solvents with a vapour  pressure > 2 kPa (30 mm Hg. 38°C)  or
            solvents that- work at temperatures > 50°C. the following features
            should be incorporated where technically feasible:

            •     Freeboard zone ratio2 should be 0.75 - 2.00, preferably  >
                  1.0 (ratio B/A in figure  A-2).

            •     Water cover (the solvent  should not  be  water-soluble and
                  should be heavier than water) should be ensured.   Water
     2 The freeboard zone ratio is the ratio between the distance from the
vapour level to the rim of  the  tank  (the  free-board height)  and the  width of
the equipment.

                    * .199* UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      C-5

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                  cover counteracts evaporation of solvent  (to the
                  atmosphere).

            •     Refrigeration coil (mandatory with vapour cleaners)  should
                  have a working temperature of about  -25°C.  A defroster
                  should be included.  The following capacities can be
                  adequate for this purpose:

                  Bath Width (m)          Cooling Capacity  (Watts/m perimeter)

                        <1.0                           190
                        >1.0                    •       290
                        >1.8                           385
                        >2.4                           480
                        >3.0                           580

            •     Adsorption filter shall be rated to  ensure  good function  (at
                  least 95% efficiency), so that outgoing solvent
                  concentrations do not exceed 25 ppm2 toward the end  of an
                  adsorption cycle.  The ventilation air flow should be  15-20
                  m3/minute and m3  bath area.

            •     Other technology (e.g., thermal destruction) that can  ensure
                  a better or more efficient control of emissions than that
                  described above.

      Table C-3 depicts, a comparison of some solvent recovery systems  and
Table C-4 summarizes available VOC control techniques, their  efficiencies,'  and
costs.

      .8.    Design of devices for  transport, filling and emptying of solvent.

      Devices for transport, storage,  and discharge'of volatile solvents
should be built as closed-loop systems.
III.  OPERATION OF THE CLEANING EQUIPMENT

      1.    Prevent solvent losses  from exceeding  10-20 WT percent  of
            purchased quantity.  Spent solvent  should be  transported and.
            stored in closed vessels only.

      2.    Close the cover after each concluded work operation  in  the
            cleaning bath.

      3.    Place the components in a manner  that  permits complete  drainage  of
            solvent.  The speed of  component  feed  should  not  exceed 3 m/min
            vertically, 3-6 m/min horizontally.  A slower feed speed is
            preferable (modern equipment permits horizontal speeds  of 0.5  -
            2.0 m/min and 0.3-0.8 m/min vertically).  Hold in the vapour zone
            for at least 30 seconds or until  condensation on  the components
     3 Concentration in mg/m3 = (molar weight in g>/22.414) (concentration in
ppm).  NOTE:  22.414 = molar volume expressed  in  litres  at 0°C  and 101.3  kPa.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      C-6

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Table  C-3   COMPARISON OF SOLVENT  RECOVERY  SYSTEMS
. TYPE OF SYSTEM
Adsorption or
absorption
Desorption
Liquefaction
Water separation
Gas concentration
Boiler
Blended solvents
Treatment of
wastewater
PRESSURE SWING
ADSORPTION
Activated carbon
granule
Pressure swing
(warm air)
Predemoisture cool
under pressure
Unnecessary
Applicable in a
wide range
Unnecessary
Applicable
Unnecessary
FIXED BED
Activated carbon
granule or
activated carbon
fibre
Temperature swing
(steam)
Cool
Necessary
Applicable in a
wide range
Necessary
Not applicable
Necessary
FLUIDIZED BED
Activated carbon
bead
Temperature swing
(hot. air)
Cool
Necessary in some
cases
LIQUID ABSORBENT
Fluorinated inert
liquid
Temperature swing
(distillation) -
Cool
(Not clear) •
Inadequate for low concentration (needs
preconcentration)
Necessary in some cases
Applicable in some
cases
Unnecessary
(Not clear)
Unnecessary
Source:   Yamabe  1991.
                      * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                          C-7

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               Table  C-4.   A Summary of Available VOC  Control Techniques,  Their Efficiencies and Costs
           Technique
                                  Lower Concentration
                                      in Air Flow
                Efficiency   Cost
                                         Higher Concentration
                                              in Air Flow
            Efficiency  Cost
                                    Application
 Thermal  incineration  **/.

 Catalytic  incineration  **/
 Adsorption  */
 (activated  carbon  filters)

 Absorption
 (waste  gas  washing)

 Condensation */
 Biofiltration
                High

                High


                High
High

Medium

High
High

Medium


Medium


High


Medium
Medium

Medium


.Medium


Medium


Low
                Medium to
                high
Low
Low ***/     Low
Wide, for high concentration flows

More specialized for  lower
concentration flows

Wide for low concentration  flows
                                                                Wide  for high concentration flows
Special cases of high
concentration flows  only

Mainly in low concentration flows,
including odour control
Concentration:  Lower < 3 g/m3 (in many cases < 1 g/m3) ,  Higher > 5 g/m3

Efficiency:     High > 95%
                Medium 80-95%
                Low <  80%
Total cost-:
High > 500 ECU/t VOC abated
Medium 150-500 ECU/t VOC abated
Low < 150 ECU/t VOC abated
  */ These processes can be combined with solvent recovery systems.   Cost  savings  then ensue.

 *•*/ Savings due to energy recovery are not included, these can reduce  the costs considerably.

**•*/ With buffering filters to dampen emission peaks, medium  to high  efficiencies  are  achieved at medium to low
     costs.
                        '• 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                          C-8

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      ceases.  Allow clean components  to drain for at least 15 -
      30  seconds  or  until  they stop  dripping.   During vapour
      cleaning, components should drain until  they are visibly
      dry.

4.    Never  clean porous materials (e.g.,  cloth,  leather,  rope)  or
      absorbent materials  in the  vapour zone.

5.    Keep the horizontal  area of the  workload to one-half the
      bath area.

6.    Maintain between the workload  and the  edges of the opening
      at  entry and exit a  distance of  < 10 cm  or  < 10% of the
      width  of the opening (calculated on the  basis of the
      workload silhouette).

-7.    Do  not allow the vapour level  to drop  more  than 10 cm when
      the workload is introduced  into  the vapour  zone.

8.    Never  spray above the vapour level.  Avoid  spraying with
      cold solvent.

.9.    Check  for leaks regularly throughout the entire system.   The
      system includes cleaning and peripheral  equipment (filters,
      storage, and filling/emptying  devices, etc.).  • In the event
      of  leakage,  the equipment must be shut off  and repaired
      immediately.   A floor sump  should be provided for collection
      of  spillage.

10.   Keep air flow  ventilation below  or at  15-20 m3/min,m2 of
      bath area unless a higher rate is required  to meet mandatory
      work hygiene limits.   Ventilation fans shall not be
      positioned  near the  bath opening.

11.   Check  to ensure that water  is  not visible in the solvent
      leaving the condensate separator (vapour cleaning system).
      Water  forms a  low-boiling azeotrope, increases solvent
      consumption, and causes corrosion damage.   Water content
      should be maintained under  50-100 mg/1.

12.   Shut off the equipment (vapour cleaning) if it is expected-
      to  remain idle for more than 2 hours.

13:   Use a  solvent  filter to extend solvent life and reduce the
      amount of solvent waste.  In general,  solvent should be
      changed when the contamination level reaches about 10
      percent by  volume.'Solvent should be  added via closed-loop
      systems with entry below the liquid surface.

14.   'Check  the acid acceptance of the solvent regularly.,  adjust
      as  necessary.   Typically, if acid acceptance values go below
      0.08 weight percent  as sodium  hydroxide, monitoring should
      be  frequent.   Corrective action  should be taken if the value
      reaches 0.04.
          1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
                          C-9'

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IV.   WASTE TREATMENT AND DISPOSAL

      Waste from degreasing processes are primarily hydrocarbons and solid
residues and, depending on the pretreatment, can contain anywhere from 20 to
70 percent solvent and water condensate.
      In some cases, single-plate distillation can be used to concentrate
soils and recover solvent for reuse.  Distillation combined with product
filtration (e.g., ultra filtration) and desiccation can produce virgin quality
solvent product assuming no other solvent may have been introduced as a
contaminant.   The oil can be concentrated for reuse.    i

      Wastewater can be treated using activated carbon to remove trace solvent
or can be sent to a waste disposal company for treatment.   Still bottoms and
unrecoverable solvent wastes can be disposed of by thermal destruction in
commercial hazardous waste incineration or industrial furnaces equipped with
appropriate scrubbing and particulate control technology.

      Other treatment methods currently being researched are ozonation,
hydrogen peroxide oxidation, carbon adsorption, and resin adsorption.  These
four processes may be used to treat wastewater generated during cleaning and
degreasing operations by removing organics from the wastewater.  Wastewater
having undergone one or more of these processes successfully will have low
enough concentrations of organics so that industrial wastewater treatment
plants (IWTPs) can properly complete the regeneration of such water.  The goal
of using these treatments is to bring the final concentration of organics in
wastewater below the regulatory agency's allowable limits.

      Table C-5 illustrates emissions achievable with optimization of solvent-
cleaning equipment.  In addition, values of specific emissions occurring in
the process of solvent cleaning are depicted in Table C-6.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     C-10

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                 Table C-5

TYPICAL EMISSIONS FROM OPTIMIZED  SOLVENT
            CLEANING EQUIPMENT
Optimization No.
1 2
Version 1 1
Version 2 2
3
4
Version 3' 5
6
7
8
Solvent
3
Chl-s*
Chl-
CFC-
Chl-
Chl-
Chl-
Chl-
s*
113
s*
s*.
s*
s*
Chl-s*
Losses
Stand-by
kg/h-m2
4
0
0
0
.0
' 0
0
0
! 0
.12
.0,2
.01
,03
.02
.02
.02
.01
0% load
kg/h
5
0
0
0.
0
0,
0,
0.
. o.
.3
.05
.02
.08
.05
,05
.05
,03
0
0
0-,
0
0,
0.
0,
P.
100% load
kg/h
6
.7-0.
.35
.15-0
.27-0
.15
.15-0
.1-0.
,06
8

.17
.6
;
.7
3

*Chl-s = Chlorinated solvent
 * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                    C-ll

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                    Table C-6              ^

 VALUES  OF SPECIFIC  EMISSIONS OCCURRING DURING
SOLVENT  DECREASING PROCESS (ECE TASK FORCE VOC)
SUBSTANCE '
Petrol
Kerosene
White spirit
Benzene ' .
Trichloroethylene
Trichloroe thane
CFC-113
AMOUNT
(kg/h-m2)
4.53
1.56
5.80
2.97
3. -94
. 4.20
14.91
t
     * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                       C-12

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                                   APPENDIX D

      CFC-113 AND 1,1,1-TRICHLOROETHANE CHEMICAL, TRADE, AND COMPANY NAMES
       In order to maintain clarity in naming the solvents used in modern
 industry,  chemical manufacturers and consumers have developed an "industry
 code"  for naming chemical compounds.  Compounds such as chlorofluorocarbons
 (CFCs)  are followed by a three number code which identifies the composition of
 the compound.   The code is defined as follows:

                                     CFC-xyz.


 where:       x     is the number of carbon atoms in the compound minus 1 (if
                   x=0, "then it is omitted from the code);

             y     is the number of hydrogen atoms in the compound plus 1;  and,

             z     is the number of fluorine atoms.

       For example, the formula for trichlorotrifluoroethane is CC12FCC1F2.
 Applying the naming convention to the formula, the code becomes:

             X = 2 - 1 = 1           No. of carbon atoms = 2
             Y = 0 + 1 = 1           No. of hydrogen atoms = 0
             Z = 3       •            No. of fluorine atoms <- 3

 Thus,  the code is 113 (this compound is CFC-113).

       There are currently ten manufacturers of CFC-113'in the U.S., Europe and
 Asia,  plus an unknown number of manufacturers in the former Soviet Union,
 People's Republic of China, and Eastern Europe.  As each has a different name
 for their product, Tables D-l and D-2 list the product names, producers, and
 CFC content for CFC-113.           .

       Different suppliers use Trade names in various ways:  all of Id's
 Arklone™ products are  113-based,  the  suffix  referring  to  the  composition,
 Arklone™ P and P-SM are pure  113,  Arklone™ E, L, A, F, etc. are blended with
 other  solvents,  such as methylene chloride, isopropanol, ethanol, etc.
 However, Dupont's Freon™ products  cover  a  wider  range,  including the
 refrigerants (for example Freon™  11 and  Freon™ 12).  The Dupont 113-based
 systems have a prefix T (e.g. Freon™  TF, TMC,  TP,  TE,  etc.).

       1,1,1-Trichloroethane is also known by several other names.  The most
 common of these alternatives is methyl chloroform.  This name is often felt to
.be  unacceptable because it implies that the product contains chloroform, which
 is  not the case.   Another name which is becoming more popular in the U.S.  is
 "trike."'  The usefulness of this name is often discounted as well since this
 name has previously been used for trichloroethylene.  Tables D-3 and D-4 list


                    * 1994 UNEP SOLVENTS, COATINGS,  AND ADHESIVES REPORT *
                                       D-l

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the producers of 1,1,1-trichloroethane,  their Trade names,  and the  1,1,1-
trichloroethane content  of the products.
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                        D-2

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     TABLE D-l.   CFC TRADE NAMES
Company
ICI
Dupont
AtoChem
Hoechst
Kali Chem
ISC Chemicals
Allied
Montefluos
Asahi Glass
Daikin
Central Glass
Showa Denko
Country
UK
US
France
Germany
Germany
UK
US
Italy
Japan
Japan
Japan
Japan •
Trade Name
Arklone
Freon
Flugene
Frigen
Kaltron
Fluorisol
Genesolve
Delifrene
.Fronsolve
Daiflon
CG Triflon
Flon Showa Solvent
1994 UNEP SOLVENTS, COATINGS,  AND ADHESIVES REPORT
                    D-3

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      TABLE D-2.  CFC-113  CONTENT OF SELECTED PRODUCTS
Company

Dupont
Product
% CFC-113
Asahi Glass Co., Ltd.
Central Glass Co.,
Ltd.
Freon TMS
Freon TES
Freon SMT
Freon MCA
Freon TA
Freori TDF
Freon TWD 602
Freon TP35
Freon TE35
Freon TMC
Freon TF
Freon PCA
94.05
95.2
69
62.8
88.9
9,9.9
91.5
65
65
50.5
100
100
Fronsolve           100
Fronsolve AE         96
Fronsolve AP         65
Fronsolve AM         50.5
Fronsolve AES        96
Fronsolve AMS        94
Fronsolve AD-7       99.5
Fronsolve AD-9       99.5
Fronsolve AD-17      83
Fronsolve AD-19      82
Fronsolve UF-1       80
Fronsolve UF-4       86
Fronsolve UF-5       90
Fronsolve AC         87.5
Fronsolve AW         97
Nanofron E  .         96
Nanofron A           75
Nanofron B           65

CG Triflon          100
CG Triflon E  •       96
CG Triflon P         65
CG Triflon M         50.5
CG Triflon ES        95.5
CG Triflon EE        92
CG Triflon E35       65
CG Triflon MES       93.3
CG Triflon Cl        98.7
CG Triflon Dl        99.5
CG Triflon D3        99.4
CG Triflon Wl        91.2
CG Triflon A         87.5
CG Triflon FD       . 78
CG Triflon CP        90
CG Triflon EC        85.5
           * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                             D-4

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       TABLE D-2..  CFC-113  CONTENT OF SELECTED PRODUCTS
                          (Continued)
 Company

'Daikin Industries,
 Ltd.
Du Pont-Mitsui'
Fluorochemicals Co.
Ltd.
ICI PLC
Product

DAIFLON S3
DAIFLON S3-E
DAIFLON S3-P35
DAIFLON S3-MC
DAIFLON S3-ES
DAIFLON S3-W6
DAIFLON S3-EN
DAIFLON S3-HN
DAIFLON S3-A
MAGICDRY MD-E6  .
MAGICDRY MD-E35
MAGICDRY MD 201
MAGICDRY MD 202
MAGICDRY MD 203
% CFC-113
100
 96
 65
 50.
 95.
 91.
 86
 90
 87.
 94
 65
 99.
 99.
                                               99.5
Freon TF
Freon TE
Freon T-P35
Freon TMC
Freon TES.
.Freon T-E6
Freon T-E35
Freon T-DEC
Freon T-DECR
Freon TMS
Freon SMT
Freon T-B1 .
Freon T-DA35
Freon T-DA35X
Freon T-DFC
Freon T-DFCX
Freon T-WD602
Freon TA
Freon MCA
100
95.5
64.7
50.5
95.2
94
65
93.5
64.5
94.0
69.1
. • 98.6
' 99.7
99.6
99.9
99.9
91.5
88.9
63-
ARKLONE
ARKLONE
ARKLONE
ARKLONE
ARKLONE
ARKLONE
ARKLONE
ARKLONE
ARKLONE
P
PSM
L
AS
AM
K
W
EXT
AMD
100
100
97.1
96
94.2
75
91.5
64.7
94.1
           * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                             D-5

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      TABLE D-2,   CFC-113 CONTENT OF SELECTED PRODUCTS
                          (Continued)
Company                   Product             %  CFC-113

Showa Denko K.  K.         Flon Showa FS-3     100
                          Flon Showa FS-3E     96
                          Flon Showa FS-3P     65
                          Flon Showa FS-3M     50.5
                          Flon Showa FS-3ES    96
                          Flon Showa FS-3MS    50.5
                          Flon Showa FS-3D •    99.9
                          Flon Showa FS-3W     91.5
                          Flon Showa FS-3A     87.5
           * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                              D-6

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            TABLE D-3.   TRADE NAMES FOR 1,1,1-TRICHLOROETHANE
      Manufacturer
        Trade Name
      ICI
      Dow
      AtoChem

      Solvay

      PPG

      Vulcan

      Asahi Glass

      Toagosei

      Kanto Denka Kogyo

      Central

      Tosoh
Genklene
Propaklone

Chlorothene* (R) Industrial Solvent
Chlorothene* (R) NU
Chlorothene* (R) SM
Chlorothene* (R) VG
Chlorothene* (R) XL
Chlorothene* (R) SL Solvent
Dowclene (R) EC-CS
Dowclene* (R) LS
1Dowclene* (R)  EC
Prelete* (R) Defluxer Solvent
Proact* (R) Solvent
2Aerothene* (R)  TT Solvent
Aerothene* (R) TA Solvent
Film Cleaning Grade
S.E.M.I. Grade
3Methyl Chloroform,  Low Stabilized - PW
3Methyl Chloroform,  Low Stabilized
3Methyl Chloroform,  Technical

Baltane

Solvethane

Triethane  •

1,1,1, Tri

Asahitriethane

1,1,1, Tri

Kanden Triethane

1,1,1, Tri

Toyoclean
Trademark of The Dow Chemical  Company.
  1  75 percent 1,1,1-Trichloroethane and  25 percent  perchloroethane.

  2   Aerosol Grade.

  3  Non-trademark product names.
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                   D-7

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  TABLE D-4.  1,1,1-TRICHLOROETHANE CONTENT OF SELECTED PRODUCTS
   Manufacturer

Asahi Chemical Industry,
Co., Ltd.
Asahi Glass Co,. , Ltd.
Central Glass Co.,  Ltd.
Trade Name
1,1,1-Trichloroethane
	Content %
ETHANA NU                       94
ETHANA VG                       94
ETHANA AL                       94
ETHANA HT                       94
ETHANA RD                       94
ETHANA IRN                      90
ETHANA FXN                      90
ETHANA SL           '94
ETHANA TS                       94
ETHANA RS                       84
TAFCLEN                         90
    (Dry cleaning solvent)
AQUADRY 50                      94

ASAHITRIETHANE                  96
ASAHITRIETHANE ALS              93
ASAHITRIETHANE UT               96
ASAHITRIETHANE LS               9.6
ASAHITRIETHANE BS               92
ASAHITRIETHANE V5               91
ASAHITRIETHANE EC Grade         96
SUNLOVELY                       95
    (Dry Cleaning Solvent)

CG TRIETHANE N                  97
CG TRIETHANE NN                 96
CG TRIETHANE NNA-               94
CG TRIETHANE F                  97
ICI PLC
GENKLENE LV
GENKLENE N
GENKLENE A
GENKLENE P
PROPAKLONE
GENKLENE LVS
GENKLENE LVX
GENKLENE LVJ
GENKLENE PT
            95.2
            95.4
            96,
            99.
            89,
            95.
            90.
            95
                                                              .5
                                                              ,7
                                                              ,6
                                                              .7
                                                              .7
                                                              ,2
                                                            99.9
Kanto Denka Kogyo Co.,
Ltd.
KANDEN TRIETHANE R
KANDEN TRIETHANE H
KANDEN TRIETHANE HA
KANDEN TRIETHANE HAK
KANDEN TRIETHANE E
KANDEN TRIETHANE EP
KANDEN TRIETHANE HB
KANDEN TRIETHANE HC
KANDEN TRIETHANE HF
            97
            97
            94
            93
            98
            97
            94
            94
            94
              * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                D-8

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  TABLE D-4.   1,1,1-TRICHLOROETHANE CONTENT OF SELECTED PRODUCTS
                            (Continued)
   Manufacturer

Kanto Denka Kogyo  Co.,
Ltd. (continued)
Toagosei Chemical
Industry Co.,  Ltd.
Tosoh Corporation
Trade Name
1,1,1-Triehloroethane'
      Content %
KANDEN TRI ETHANE HG
KANDEN TRIETHANE HS
KANDEN TRIETHANE HT
KANDEN TRIETHANE N
KANDEN TRIETHANE ND
KANDEN TRIETHANE SR
KANDEN TRIETHANE SRA
KANDEN TRIETHANE EL
KANDEN TRIETHANE ELV
94'
99
97
100
97
90 ,
, 91
97
97
Three One-R                     96
Three One-S                     95
Three One-A              •       95
Three One-AH                    95
Three One-S(M)                  95
Three One-F                     95
Three One-TH                    95
Three One-HS   '                 95
Three One-EX                    90
Shine Pearl                     94
  (Dry Cleaning Solvent)

Toyoclean EE                    97
Toyoclean T                     97
Toyoclean SE      ,.   •           84
Toyoclean 0        '            100
Toyoclean HS                    96
Toyoclean 1C                    91
Toyoclean NH                    96
Toyoclean AL                    95
Toyoclean ALS                   91
Toyoclean EM                    96
              * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                 D-9

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                                  APPENDIX E

                                  SITE VISITS
      The following is a summary of  the  site visits  conducted by  committee
members to aid in the preparation of the  1991 United Nations Environment
Programme (UNEP) Solvents, Coatings,  and  Adhesives Technical Options  Report.

Site Visit

      IBM Jarfalla

      The IBM Jarfalla plant was built in 1970 and specializes  in building
printers for all IBM markets.  Control units for  disk  storage and bank
terminal supports are also bviilt at  the plant which  employs about 900 people.

      This facility now has a strict environmental policy  after having been
self-admittedly one of the worst users of chlorofluorocarbons (CFCs)  in
Sweden, using 16 tonnes of CFC in 1986.   They effectively  now use no  CFCs.
They also have a complete.control inventory of all chemicals under very strict
regulation and an environmental policy which began in  1971.

      IBM Jarfalla began an energetic program of  elimination of CFCs  by
altering/changing the final steps of the  initial  sequence  as well as  changing
the cutting oil.  Stage I, which consisted mainly of "housekeeping" measures
resulted in CFC use dropping to 4.7  tonnes in 1988,  a  64%  reduction.   Stage II
involved a CFC phase-out by either a cessation of oil  use  or a  switch to  oils
which are water soluble or which form emulsions.  In Stage III, the drying
process was phased out.  This was replaced by deionized  (DI) .water rinse  with.
and without ultrasonics.  The final  stage is a dip in  an inhibitor.   Finally,
a hot air dry is applied.  All of these processes'occur  with no notable change
in cleaning time.

      The oily water is passed through an ultrafilter  which costs 600.00  SEK.
The total cost for CFC phase-out at  Jarfalla was  300.00  SEK.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-l

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Site Visit

      Siemens-Elema

      Siemens-Eleina specializes in the production  of medical  apparatus.
Specifically, it specializes in medical applications such  as  X-ray technology,
electromechanical devices  (such as pacemakers),  EKG equipment,  and
respirators, as well as dental and hearing aid devices.  The  firm employs
about 2,000 people and is  considered to be an extremely  small CFC user.
1,1,1-Trichloroethane is used primarily to clean the pacemaker circuit boards.
1,1,1-Trichloroethane usage is estimated to be 4.2 Tonnes/year as a cold spray
in an enclosed chamber.

      The alternatives to  CFC and 1,1,1-trichloroethane  .(TCA) cleaning are
described below.                                         '
Alternatives to CFC as Cleaning Agents at Siemens-Elema

Electronic circuits for pacemakers:

Old Method                                Present Method

Serial cleaning with           '82-83      Spray  cleaning with  1,1,1-
Arklone F                                 Trichloroethane*

Vapour zone soldering  .                   IR-soldering
Freon 113 as fluid                '89

Other electronic equipment:           '     ,

Old Method                                Present Method

Semi-manual cleaning with perchloro-      Rinsing with deionized water;  hot
ethylene                          '89      air

* To be changed 92-93
      Plans are to phase out CFCs and TCA with  either  isopropyl  alcohol  (IPA)
or Ethanol sprays preferably by the end of  1991, but no  later  than 1993.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-2

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Site Visit

      BALZERS AG

     . The Balzers Group is a division  of Oerlikon-Buhrle,  the  latter employing
30,000 persons worldwide with sales of almost  $3 billion.   Balzers,  with 3,900
employees and $300 M sales, are world  leaders  in high vacuum and thin film
techniques.  Both Balzers and Oerlikon-Buhrle  are  actively pursuing  a CFC-113
policy, based initially on usage audits.  Most usage within Balzers  has
already been eliminated.   .

      Amongst their strictly defined product lines, Balzers also produces
accessory equipment.  This equipment includes  aqueous cleaning machines for
substrates and lenses prior to vacuum  coating.  A  typical  cleaner may clean
ultraspnically about 500 ophthalmic lenses per hour.  Drying was originally
performed using alcohol followed by CFC-113.   A demonstration  was made of a .
modified machine which successfully dried the  components by partially
recirculating hot air.  This machine will be marketed in the future.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-3

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Site Visit

      Leica Heerbrugg AG

      Leica Heerbrugg AG is a multinational  organization which manufactures
precision optical instruments, often with  complex  components.   Total world
sales reach approximately US$850 M.

      Sensitive optical glasses have to be perfectly  cleaned before coating.
Leica Heerbrugg AG has adopted mixed aqueous/solvent  techniques for cleaning.
Previously, the final stages were  in alcohol followed'by CFC-113.   Their
active corporate environmental policy  dictates  as  rapid a phase-out as
possible and experiments have been made involving  the following processes:

      •     drying in alcohol vapour
      •     drying in warm air
      •     drying by infra-red
      •     drying in warm air followed by evacuation
      •     drying in 'low pressure microwave plasma

None of these processes have shown a distinct lead over the others and all
have considerable disadvantages.   The  Committee suggested that Leica might
want to examine alcohol/perfluorocarbon drying  as  another approach, in the
meantime taking care to limit CFC-113  emissions.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-4

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Site Visit

      FFV Aerotech AB

      FFV Aerotech is a member of the  large  industrial  group  Celsius
Industries.  The Celsius Group employs  13,000 people  internationally  and had
1991 sales projected at 9000 MSEK.  The products manufactured focus on the
marine, aviation, and electronics sectors.   FFV Aerotech AB employs 970 people
and markets maintenance and technical  consultant services  to  the  Swedish
Defense Forces.  It also develops advanced systems  for  the Swedish Air Force
and carries out modification.  The functions performed  using  ozone depleting
solvents include the repair of airborne instruments and the development and
manufacture of modifications.  This FFV plant is one  of the four  industrial
concerns in Sweden to receive an exemption (500 kg  for  1991)  to the phase-out
of CFC-113.  They have evaluated alternatives for their precision cleaning
requirements and have approved a cleaning concept using ethanol and a KLN
Ultraschell GmbH machine.  Three of the machines will be in operation in mid-
August and a fourth is in  the process  of procurement.

      With the fourth machine, they will be  completely  free'of the use of CFC-
113 in their precision cleaning operation.   The exemption  granted them for  the
use of CFC-113 past January 1991, expires in August 1991.  They are satisfied
that the alcohol cleaning  process they are installing will meet all Swedish
requirements for explosion-proof, safe, clean effluent  operation.  One problem
area that remains to be solved is the  identification  of a  satisfactory solvent
for removing a fluorinated grease of the "Krytox" type.' For  low  temperature
testing, the Company has successfully  applied carbon  dioxide  impingement.
                    * 1994 UNEP SOLVENTS,-COATINGS, AND ADHESIVES REPORT *
                                      E-5

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Site Visit

      Plamex S.A.

      Plamex S.A. manufactures  telephone and other communication headsets.  It
is a subsidiary of Plantronics  Inc.,  a company based in California, U.S.A. '
The company uses a CFC-113 blend to  clean printed circuit boards.  The
facility consumes around 36  drums annually (1 drum contains 55 gallons of
solvent).  Of this amount, 6 drums of material is recovered and sent to a
recycling facility.   Each drum  of virgin material costs about US$950.

      After observing the operations,  the committee members offered a number
•of suggestions on ways to reduce solvent use in the facility.  These include
the following:

      •     modification of  vapour degreasers being currently used to replace
            lift lids with roll-back type lids;  increased freeboard height,
            and a recommendation that the spray wand be used sparingly and
            properly;

      •     use of milder flux  for rework to make it easier to clean;

      •     specification of solderability requirements of components before
            acquisition so as to minimize rework;

      •     careful  storage  of  components in inert atmospheres so as to
            minimize any contamination;  and

      •   % rationalize the  use of vapour degreasers in the facility so as to
            reduce the number.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-6

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Site Visit

Ensambles Magneticos. S.A.

      Ensambles Magneticos, S.A.  is a manufacturer  of magnetic recording heads
for rigid disc drives.   It  is a  subsidiary  of  Sunward Technologies  Inc.,  a
firm with headquarters  in California, U.S.A.   The company  uses CFC-113  for
precision cleaning and  defluxing of printed circuit board  assemblies.

      Ensambles engineers implemented a  simple system that .allows workers to
slowly remove parts to  reduce dragout.   The technique uses a fixed  rod  mounted
below the degreaser lid and a basket handle with hooks that  allows  the
operator to raise the basket several inches at a time allowing the  parts to
drain.

      The committee members gave a number of suggestions to  the facility
managers on ways to reduce  the use of ozone-depleting substances (ODSs).
These included the following:             •     • ' •

      •     the use of  an alcohol based  wire cleaning solvent instead of CFC-
            113 based solvent.   This would  involve  investigation of the  type
            of drawing'oils used in the  manufacture of the wire and its
            solubility  with alcohol

      •     change in the method of storing solvent drums  to ensure minimal
            storage and handling loss; the  working  drum should be stored in  a
            cool enclosed space

      •     improvement in  the solvent transfer procedure  from the  drum  to the
            degreaser.   The use  of manual or electric drill  powered pumps to
            pump the material from the drum to the  degreaser was recommended

      •     replacement of  a lift lid with  a roll-back type  lid on  the
            degreaser
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-7

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 Site Visit

       Saab/Scandia

       Saab  Combitech Electronics produces electronics for each of the
 Saab/Scandia business groups and sells contract board assembly services to
 outside  clients.   They had 1990 sales of 1.9 billion with 204 MSEK profit.
 One-third of their solvent using production is for automobiles;  one-third for
 space, automation,  transportation control,  and military;  and one-third for
 contract assembly.

       Their products range from simple,  consumer grade products to
-sophisticated products for high reliability applications  (automobile safety
 systems,  missile  control modules,  space technology).

       In 1986,  one year prior to the Montreal Protocol,  Saab made a corporate
 decision to.reduce dependence on chemicals  that deplete the ozone layer.
 Literally overnight, the electronics division was instructed to cancel plans
 to purchase new CFC vapour degreasers and to freeze annual use of CFC-113.
 This policy change occurred during a period of rapid sales increase.

       Saab  had been using a combination of in-line vapour degreasers, aqueous,
 and had  cleaning  processes.   They used CFC-113 but no other chlorinated
 solvents because  the federal environmental  agency would not grant them a
 chlorinated solvent emission permit.  The sequence of CFC elimination was:

       1986   Corporate.decision to freeze CFC. use
       1987   Vapour-phase CFC processes eliminated
       1988   Carbon adsorption system installed
       1989   Low-solid flux implemented
             Controlled atmosphere soldering machine purchased
       1990   Controlled atmosphere/low solids implemented
       1991   Process simplified; new flux investigations

       Saab  is now manufacturing without the use of CFC-113 or methyl
 chloroform  solvents and is satisfied with the quality of its final products.
 They use Lonco 25 in a SEHO controlled atmosphere wave soldering machine;
 water  soluble flux in an in-line aqueous/saponifier process; and alcohol
 cleaning (90% ethanol,  10% IPA) for rework and for touch-up prior to conformal
 coating  (if used).   Alcohol is also used for final cleaning of products for
 military customers.  Boards are now cleaner than when they were using CFC-113.

       The sequence of changes was more expensive than would be necessary today
 because  the controlled atmosphere machine was an early generation model and
 there  were  difficulties of optimization resulting from oxygen contamination of
 the nitrogen supply and an inaccurate oxygen sensor.  The investment costs are
 being  repaid from savings in operating costs.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT «
                                        EQ
                                       - O

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      Atsugi Unisia Corporation

      Atsugi-Unisia is a manufacturer of a wide range  of  car  components
including hydraulic tappets  (valve lifters), pistons,  clutch  plates,  4-wheel
steering systems, dampers, and air conditioning systems.

      During 1990, their total use of ozone-depleting  materials was:

                  CFC-12                          96  tonnes
                  CFC-113                       126  tonnes
                  1,1,1-Trichloroethane '        864  tonnes

      The CFC-12 was used for air conditioner compression testing.  The  CFC-
113 was used for cleaning parts .after machining and  before heat treatment.
1,1,1-Trichlbroethane was also used for this purpose and.  for  electronics .
cleaning and had a very important use as a cleaner for pistons before the
application of a PTFC/phenolic resin low friction coating.  This  is used as a
long-life, low-friction coating on pistons for high  performance turbo blown
engines.                                                 '       .            i

      Atsugi plans to introduce aqueous alkali cleaning of the hydraulic valve
lifter parts, and the piston precleaning and both aqueous cleaning and burn
off degreasing for pre-heat treatment cleaning.

      Currently aqueous cleaning of pistons is causing some loss  of adhesion
of the low friction coating and some adjustments  to  heat  treatment will  be
required after both aqueous and.burn off degreasing.   The company plans  to be
out of CFC-113 and CFC-12 use by 1993 and out of  1,1,1-trichloroethane by
2000.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-9.

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Site Visit

      Minebea Group

      Minebea Co. Ltd. heads a group of 52 subsidiaries and 14 affiliates with
more than 25,000 employees and a sales turnover of almost Y230 billion.

      The Company originated in 1951 as a maker of miniature ball bearings and
is now the world leader in this field.  The Company has pursued a course of
expansion and diversification action, derived from both internal growth and
strategic acquisitions.  Precision technology and production expertise have
been central to Minebea's development.

      The visit was hosted by Mr. Mizugami, the Japan based Managing Director
of Minebea.  The plant at Bang-Pa-In, north of Bangkok, is the largest
miniature precision bearing plant in the world.

      The Group operation in Thailand comprises:

                  Pelmec Thai Ltd.
                  NMB Hi-Tec Bearings Ltd.
                  NMB Precision Ball's Ltd. at Bang-Pa-In
                  Minebea Thai Ltd.
                  Thai Ferrite Ltd.
                  Taal Products (Thailand) Ltd. at Navanakoru
                  NMB Thai Ltd.
                  Minebea Thai Ltd.  (Ayuthlaya Plant) at Ayuthlaya
                  Minebea Electronics (Thailand) Co. Ltd.
                  Minebea Thai Ltd. Lopburi Plant at Lopburi
                  Minebea Thai Agroindustry Co. Ltd. at Pathumthani

      The company first came to Thailand in 1972 with a small plant
manufacturing finished bearings from parts made in Japan.  Currently they
employ 17,000 people at Bang Pa-In and make 55 million pieces (i.e., finished
bearings) per month.

      Their current use of CFC-113 and 1,1,1-trichloroethane are:

                  CFC-113                        90 tons per month
                  1,1,1-Trichloroethane         260 tons per month

      Bearings are made from 440C  (stainless) and 52100 carbon steel
(corrodible).   They also have a material similar to 440C, known as NMB alloy
DD, which has quieter running characteristics.

      They plan to phase out CFC-113 use by the end of 1995, and 1,1,1-
trichloroethane use by the end of 1997.

      The current method for cleaning bearing parts (rings, balls, retainers
etc.) is:

                  1,1,1-Trichloroethane degrease
                  Detergent water clean
                  Wash in deionised water
                  Dewater in Freon TDFC


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     E-10

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                  Rinse  in Freon TF

      The CFG-113 replacement process will be:

                  Water  detergent clean
                  Water  rinse
                  Dewatering oil

      It should be  emphasized that the cleaning process described above for
bearing parts was demonstrated.   However,  this process cannot be used for
assembled bearings  because there is the possibility of chemical reactions
occurring when dewatering oil is mixed with lubricant oil from bearings.
Therefore, their main concern was to find a method for cleaning assembled
bearings to remove  particulate contamination.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-ll

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 Site  Visit

       ABB Automation

.Circuit  Pack Assembly:

       Chronology
       Pre-1974            TH    Rosin Flux      Perchloroethylene clean
       1974-1985           TH    WSF             Water clean
       1985-1987           TH    WSF             Water clean
                          SM    Rosin           CDC clean*
       1987-1989           TH    WSF             Water clean
                          SM    LSF             Water clean for solder balls**
  * ABB  determined that they could not use WSF for SM due to component
 compatibility issues.

 ** Water  is  used to clean LSF soldered boards only for the purpose of avoiding
 BSD  problems during brushing to remove solder balls.  A dry brushing technique
 is desirable.

 Policy  Deployment:

 •    Local  pressures  from authorities and public.
 •    Required elimination of 1,1,1-trichloroethane and methyl chloride by end
      of  1987  for PCB  fabrication
 •    Permit denial for use of CFC for printed wire assembly (PWA) forced
      changes  to occur
 •    Internal pricing of materials is used to force individual product lines
      to  seek alternatives

 Obstacles:                                     .      •.

 •    Alkaline PC board processing has improved quality, but finer features
      will require improved technology

 •    LSF narrows process window, produces solders balls, causes
      crosses/icicles

 Additional Information:
                                  *
 •    ABB Automation was using a small amount of CFC-113 to clean artwork
      films.   Changed  over to alcohol (IPA) earlier in 1991,

 •    Produces 300,000 boards/yr (15,000-17,000 m2/yr).
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-12

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 Site  Visit

       Siam  Compressor Industry Co.  Ltd.

       This  company is a joint Nippon-Thai venture,  the main owners being
 Mitsubishi  Electric Co.  Ltd.  and the Siam Cement Co.  Ltd.   The product line is
 exclusively small unit air-conditioner rolling piston type rotary compressors
 (approx.  2,250-11,000 kCal/h) which are used in equal parts for the domestic
 and export  markets.  The production capacity is 300,000 compressors per year.

       The only solvent use is for cleaning diverse  castings after machining.
 For this  process.,  trichloroethylene is used in a conveyorized "hanging part"
'machine at  1 m/min.  The key point is that the machine was constructed under
 license in  Thailand to a Japanese custom design.  As  the parts being cleaned
 were  soiled with,  essentially,  non-soluble and soluble cutting oils and
 grinding  grit,  with blind holes and intricate topography,  ultrasonics were
 liberally applied in immersion tanks.

       Internal distillation was sufficient to maintain adequate solvent purity
 as  well as  a vapour phase final rinse.   The machine height-was sufficient to
 ensure that the entry and exit slots were well over the freeboard.

       .Typical trichloroethylene (TCE) losses were very small,  evidenced by the
 fact  that the average measured exposure level is 2  ppm at any place.   The
 average net and consumption must have been small with two 250 kg drums of new
 solvent used per month less the solvent content of  three,to four similar drums
 produced  for solvent reclamation (percentage of solvent unspecified).   Only
 new solvent was used.  The used solvent was sent to a government reclamation
 facility^                                                            •;

       Although not relevant to the solvents committee,  a small quantity of
 HCFC-22 were used for Quality Control/Quality Analysis purposes.  Currently
 this  is all vented, but it is planned to reclaim it..shortly,  budgetary.
 approval  being currently in the process.   Very tight  wastewater control is
 also  applied,  an order of magnitude better than Thai  regulations for suspended
 solids, dissolved metals and biological oxygen demand (BOD).   The wastewater
 is  used for irrigating the factory lawns.  This example is evidence that tight
 environmental control is possible and economical in a developing nation and
 the Solvents,  Coatings and Adhesives Committee and  the Economics Committee
 were  unanimous in congratulating SCI on keeping such  an exemplary "tight
 ship".
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-13

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Site Visit

      Nissan - Japan

      Nissan Motor Co. will phase out  its use  of CFC-113,  -11,  and -12 by the
end of 1994, the fastest schedule for  a motor  company worldwide.   By March,
1991, CFC-12 recovery and recycling  equipment  was installed in 3,000 Nissan
service factories throughout Japan.  By 1994,  HFC-134a will be phased in as an
alternative refrigerant for production models.    CFC-11 blowing agent for foam
has already been replaced with an air  based  foaming system.   CFC-113 will be
replaced with aqueous, semi-aqueous  systems, and other alternatives by March,
1992.

      Nissan Motor Co. cleans plastic  car bumpers with methyl chloroform
before painting.  These uses will be replaced  with an aqueous cleaning
process.
                    * 1994 UHEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-14        ,

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'Site Visit                             -

       AT&T - Thailand
  '                          •

       AT&T has a consumer products factory in Bangkok, Thailand.  It opened in
 Spring,  1990 CFC-free' due' to the upfront planning prior to opening.  This
 factory,  along with several other A&T operations, is furthering AT&T towards
 it's corporate goal to eliminate emissions of CFCs from manufacturing by the
 end of 1994.

       Mr.  Ken Lannin, Managing Director of the factory welcomed the committee
 and made opening remarks.

       Dr.  Stephen Andersen, the committee chairman,  listed AT&T's leadership
 in environmentally-sound manufacturing including:  aqueous cleaning work,
 terpene  technology announcement in 1988,  leadership in Ad Hoc Solvent Work
 Group CFC benchmarking and alternative testing since 1988, UNEP committee
 membership in 1989, International Cooperative for Ozone Layer Protection
 (ICOLP)  inception in 1990,  and United Nations Environment Programme (UNEP)
 committee membership in 1991.  Dr. Andersen asked for AT&T's help in his
 proposed partnership between U.S. Environmental Protection Agency (EPA), Thai
 government, and Japan's Ministry of International Trade and Industry (MITI)
 which will work to eliminate CFC usage in Thailand.

       Mr.  Greg German, Director, Engineering,'gave an overview of the factory
 in preparation for the tour.   There are four assembly lines that make 10-12
 corded telephone products.   Low solids flux applied with AT&T spray fluxers is
 used to  wave solder bare copper circuit boards coated with either a rosin-
 based or imidazole-based solderability preservative.  By carefully selecting
 the right low solids flux and controlling the quantity with the patented AT&T-
 developed fluxer, postrsolder cleaning is not necessary and therefore not
 done.  The first generation AT&T spray fluxers are used in this factory.
 These,  and second generation AT&T spray fluxers, have been, implemented on many
 AT&T lines.  Also, this technology is being offered commercially and has been
 implemented by other companies in the'U.S.

       The Moving Coil Receiver (MCR) line uses a hot-melt glue that does not
 contain  1,1,1-trichloroethane.   Soldering is done manually with a .low solids
 flux cored solder.                   .        '

       Plastic moulding is accomplished using a mould release compound with
 isopropyl alcohol (IPA)., not CFCs.

       Recycling in the factory is performed wherever possible including
 plastic,-wood, paper, and moulding re-grind.

       The director of purchasing and transportation, Visan Palattanavit, has
 started  receiving surveys back from vendors regarding their CFC usage,  fo do
 this,  he obviously has' good knowledge of all suppliers.  He stated that, other
 than IPA,  very few chemicals are used.
 (Guth)
                     * 1994 UNEP SOLVENTS,  COATINGS, AND ADHESIVES REPORT *
                                      E-15

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Site Visit

      Nissin Electric Co.. Ltd.

      .Nissin Electric Company, Ltd. produces electrical substation equipment,
reactive power compensation equipment, control systems, charged particle beam
for semiconductor manufacturing, and engineering services to outside clients.
The company had sales of 80,188 million Yen (US$507 million) in 1990 with a
profit of 2,726 million yen (US$17 million).

      Nissin has reduced its consumption of CFC-113 from 11 tons per year in
1986 to 4 tons in 1990.  Over 40 percent of the 1990 consumption was used for
defluxing of printed wiring assemblies (PWAs) as a result of the electronics .
soldering operation.  The greatest part of the consumption  (46.7 percent), was
used for degreasing of oils from high vacuum equipment and  13.3 percent for
degreasing of oils prior to thin film coating.  The company has a. goal of
eliminating CFC-113 use by the end of 1995.  Alternatives for replacing CFC-
113 include the use of alkali washing processes to clean metal parts and the
use of no-clean fluxes for PWA operations.

      Nissin also consumes significant quantities of 1,1,1-trichloroethane.
Reductions have been made from a 1986 .high of 81 tons per year to 76 tons per
year in 1990.  The greatest use of 1,1,1-trichloroethane (55.8 percent) is in
the degreasing of metal parts after machining operations and prior to chemical
finishing processes.  The next largest consumption of 1,1,1-trichloroethane
(35.2 percent) is for dissolving of epoxy resin during cleaning/maintenance of
equipment which mixes the resins for use in encapsulation processes as
electrical insulating materials.  Finally, 9 percent of the total 1,1,1-
tr.ichloroetharie consumption is used for miscellaneous degreasing of other
products.  Alternatives for replacing 1,1,1-trichloroethane include alkali
cleaning, isopropyl alcohol cleaning and the development of other alternative
cleaning agents currently under development.

      Although the minimization of 1,1,1-trichloroethane has been strongly
pursued, a net decrease of 5 percent has been realized to date.  Nissin feels
that the elimination of 1,1,1-trichloroethane may be more difficult than CFC-
113 because of the difficulty in finding a safe (worker exposure),
nonflammable solvent with the solvency power for mixed epoxy resin that is
provided by methyl chloroform.  Nissin.is also 'requiring their subcontractors
to reduce and eliminate the use of CFC-113 and 1,1,1-trichloroethane on
products supplied to Nissin.
(Felty)
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     E-16

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Site Visit

      Hitachi Construction Machinery  Co..  Ltd.

      Hitachi Construction Machinery  employs  4,500  people and manufactures a
variety of construction machines  including excavators,  crawler cranes,  shield
machines, etc.  Net sales were approximately  US$  1870 million in 1990.

      In 1988, this plant consumed  15 metric  tones  of CFC-113.   The
consumption was reduced to 0.6 metric tonnes  in 1990 by introduction of liquid
petroleum gas (LPG) spray and water based  cleaning:  CFCs will be eliminated
in 1995.

      In 1990, 212 metric tons of 1,1,1-trichloroethane were  consumed at this
location.  1,1,1-Trichloroethane  will be eliminated in  1998.   Recent
developments and observations aiding  in the phaseout of these materials
include the following:

      •     A water based alternative has  already been  introduced for
            components cleaning.                      '

      •     1,1,1-Trichloroethane is used  as  a cleaning agent in the process  .
            of heat treatment.  Alternative technologies  are  now being
            investigated in several kinds  of  agents.  These alternative
            technologies are rather difficult than  those  technologies
       >     currently being used.                 ,

      •     Operating costs, of water-based cleaning is  lower  than previous
            solvent cleaning costs.  But,  operating costs for alternative
            cleaning in heat treatment processes  is estimated to be higher
            than that, of 1,1,1-trichloroethane.

      •     Waste water is separately treated in  three  systems  for different
   .         kinds of wastes.                     •
                      1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-17

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Site Visit

      National Research Institute for Pollution and Resources  - Japan

      National Research Institute for Pollution and Resources  is concerned
with a wide range of research fields related to exploitation,  processing  and
utilization of. mineral resources and energy, mine and industrial safety and
environmental protection.  Research subjects include mineral resources
development and utilization, energy development and utilization, environmental
protection, and mine and industrial safety.

      The visit to NRIPR at Tsukuba focused primarily on the research directed
at the destruction of CFCs.  Presentations were made on catalytic
decomposition, recovery by adsorption, decomposition by thermal plasma, and
thermal decomposition.

      Catalytic decomposition is accomplished  in a reactor  at  relatively  low
reaction temperatures of about 300°C using a fine powder catalyst.  The
catalyst basis is HY-Zeolite with Ti02/ZrQ2.   The  residence time is 1-2
seconds and, at flow rates of 50 I/minute, is  100 percent efficient.  The
apparatus  is laboratory scale.  H-mordenite and Ti02/Zr02 have the  highest
activity and selectivity.                   .

      Recovery by adsorption is based on adsorption on zeolite.  Adsorption is
effected by the zeolite pore size rather than  chemical surface interaction.
The process is based on size exclusion as the  adsorption preference is in the
order of CsY>KY>NaY where  the large cation influences adsorption.  Microwave
radiation  processes can be used for selective  adsorption of CFC in water
vapour.

      CFC  decomposition by thermal plasma reactor was achieved using a JEOL RF
generator.  Inductively coupled, radio frequency, plasma reaction at 10,000°C
using Argon gas were the conditions employed...  The product  distribution in.
CC13F decomposition by R.F. plasma was not encouraging where at least six
different  CFC decomposition products were identified.

      Thermal decomposition of CFCs and industrial chlorinated organics
studies were conducted in  the presence of methane in which  oxygen  was. in
excess.  The examination of thermal decomposition products  revealed that  the
99 percent destruction temperature (760°C) was almost the same with hexane as
methane.  The 99 percent destruction temperature for CFC-12 was 820°C.

      Optimum conditions involving dilution with hydrocarbons  and  sufficiently
high temperatures must be  determined for complete incineration.

      While these procedures operating at laboratory scale  are encouraging in
destruction efficiency and cost, the scale-up  to industrial concentration
destruction requirements needs to be explored  on both an efficiency, and costs
basis.  NRIPR researchers  feel that "commercial" feasibility may take about 1-
2 years and the strong candidate will be incineration.
                    * 199* UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     E-18

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Site Visit

      Digital Equipment Corporation. Republic of Singapore

      Digital Equipment Corporation is one of the world's largest  suppliers  of
networked computer systems, software, and services.  Digital  leads the
industry in open, multi-.vendor systems integration.  An  international company,
Digital does more than half of its business outside  the  United  States,
developing and manufacturing products and providing  customer  services in  the
Americas, Europe and the Pacific Rim.
            f
      The purpose of the visit was-'to observe the surface mount module ,
manufacturing process which utilizes aqueous cleaning 'for removing process
flux chemicals.  The aqueous cleaner being utilized  in Singapore is the High
Performance Aqueous Microdroplet Module Cleaning system  introduced by Digital
Equipment Corp. in Washington, D.C. on April 5, 1990.   ;

      The Singapore plant  converted from being a CFC user for cleaning surface
mount products to an aqueous process during 1991. .The plant  tour  exhibited
how the system was being utilized, including showing its operational
performance with the particular products being manufactured in  the plant.

      Questions by the participants ranged from defining the  total
installation time, understanding the energy usage of the equipment to the
amount of CFC's eliminated by changing to an aqueous cleaning process.  During
the discussions it was mentioned that the advantages outweighed the
disadvantages and the process is successful and is meeting all  the
manufacturing expectations.  It was also demonstrated that aqueous cleaning  is
a viable reliable alternative, capable of successfully replacing CFC's as a
cleaning methodology.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-19

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         UNEP SOLVENTS  COMMITTEE  -- DUSSELDORF, GERMANY  -  2 JULY 1991
      Attending this meeting were  several  speakers  and  guests  representing
different associations and  trade groups.

      Dr. Heinrich Kraus                   Ministry  of the  Environment
                                           (Speaker)
      Dipl.-Ing. Christian  Hering          Duerr  (Speaker)
      Mr. Peter Gunther                    Machining-Association
      Dipl.-Ing. Rupert Rompel             Environmental Affairs  ZVEI  (German
                                           Electric  and'Electronics
                                           Manufacturers Association)
      Dipl.-Ing! Robert Auer von Brunkau   VCI
      Dr. John Place                       European  Chemical  Industry
                                           Federation
      Dr. Hiemke                           Environmental Ministry - Germany
      Prof. Nader            .              VCI      ^
      Mr. G. Gabelmann                     ITT Teves
      Ing.-Dr. W. Schiegl                 -Siemens AG
      Dr. Anne Janssen                     Mannesmann
      Mr. Karl-Heinz Pieper               Ministry  of Finance
      Mr. H. Schwenzer                     IBM Germany

      The meeting was hosted by the German representatives of  the Solvents
Adhesives and Coatings Committee,  Gunter Gabelmann  ITT  - Teves,  and Dr.
Wolf-Eberhard Schiegl, Siemens.

      Dr. Schiegl started the meeting off  with a short  description of  the
German situation, which is  that they are faced with a phase  out  of ozone
depleting solvents by the end of 1992 and  they have a difficult  job ahead  of
them.  The industry was working with the Environmental  ministry  on a proposed
date of 1993 when, at the last minute, the date was moved up to  1992 by the
Burndersrat (Upper House).  This will make things very  difficult for German
industry.  Dr. Schiegl mentioned that it would be especially hard on the small
printed circuit board manufacturers.  Mr:  Schiegl then  introduced Dr.  Kraus  of
the Ministry of Environment.

      Dr. Kraus gave a very detailed review of the  laws which  are affecting
the use of solvents and, in particular, those solvents  that  are  ozone
depleting substances.  There are two different regulations facing Methyl
Chloroform users in Germany; one is a prohibition on ozone depleting
substances which was to go  into effect on  August 1, 1991, and  the other is the
revision of the Emission Control Act (2 BImSch V),  in effect March 1,  1991.

      Article 5 of the CFC  Prohibition Ordinance deals  with  cleaning agents
and solvents.   This covers  the manufacture of products  and formulations
containing ozone depleting  substances to an extent  greater than  1 percent  by
weight.   There are exceptions to this part, such as use as a chemical  cleaning
agent in closed systems under 2 BImSch V,  or to manufacture  other less
hazardous substances.  The  competent local (Laender) authorities may give
temporary exemptions if the use is perceived to be  absolutely  necessary.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     E-20

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      Article  2  of the  Emission Control Ordinance (2 Bimsch V)  limits volatile
halogenated  solvents  for  operating closed cleaning facilities to
perchloroethylene,  trichloroethylene,  and dichloromethane,  in a technical pure
form.

      CFC-113  and  CFC-11  can be used until December 31,  1991 in already
constructed  facilities.   By January 1,,1993,  methyl chloroform  will no longer
be allowed unless  by  exemption.

      2 Bimsch V defines  the competent authority  that may allow for exemptions
as the Laender authorities, as  well as the circumstances  and individual
requirements (such as economic  hardship)  for  obtaining, exemptions.   The local
authorities will have this authority.

      The German regulatory action was thought by the Bundersrat to be -
necessary since  so much TCA is  used, and  its  "long"  lifetime allows it to
easily reach the stratosphere.

      Dr. Anderson summarized Dr.  Kraus'  talk as  follows:

      Phase-out-was reviewed as  technically feasible  by 1994, with  special
needs being met  by exemptions.   The implication is  that Germany can accomplish
this phase-out by  1992 with heroic -efforts and can  do it  economically by  1994.
Germany is a sophisticated, developed  country, and  as such,  should  be able  to
help other less  developed countries, especially those dominated by.  multi-
nationals such as  South Korea and  Singapore.

      Dr. Anderson strongly urged  that the German government and industry
should contribute  their experience to  the  on-going  panel  work and participate
in the coming  working meetings  (August/September).   Dr. Anderson mentioned  the
example of Mexico  and their partnership program with  the  USA; they  are ready
to receive from  the World Bank  Fund and the Multi-Lateral funds .to  start  the
program.

      Discussion of Dr. Kraus'  presentation was as  follows:

      There was  some concern that  German  industry,  with this early  phase-out
date, might make an alternative  choice that appears  to be environmentally
acceptable, then need to  change  again,  thus undergoing the  cost of  the change
twice.

      Mr. Rumple pointed  out that  both the Environmental  Ministry and Industry
had been negotiating for  a 1994 date,  and were surprised  at the last minute
change to 1992.

      Dr. Kraus  is  concerned that  this law was passed too quickly and without
enough deliberation and planning regarding the scope  of its potential impacts.
It would be possible to amend the  law, but this would take  two  years,  which is
beyond the cut-off date.

      Next, Mr.  Gabelmann gave  a description  of the experience  of ITT-Teves.
Teves began to look at alternatives after the 1986  BiMSch laws  were passed.
Mr. Gabelmann  traced the  timeline  for  replacement of methyl chloroform in the
ABS manufacturing  system.  It took from January 1987  until  April 1991 to
evaluate, test,  select, install, start up, and de-bug the alternative system.


                    *' 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     E-21

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The ABS system involves a high priority for safety, multiple substrates and
complex geometry.

      Mr. Gabelmann pointed out the availability of parallel cleaning lines
which allowed them the flexibility to be testing the new line without
interfering with production; a luxury smaller companies .will not have
available.  They estimated the cost to be 1.7 MM DM.  A total of 12 cleaning
lines need to be replaced in this one factory.

      The problem areas they ran into were compatibility with other materials,
adhesion of parts, and compatibility with other process, such as
electroplating.  There were problems with the equipment, such as chain drives,
and electrical control filters.  They also had new quality demands to deal
with, such as new parts and materials to clean, that were not part of the
original plans.

      Small companies have special concerns,  inadequate knowledge of the law,
difficulty getting information, lack of trained employees, production demands
on existing equipment which limits testing opportunity, and the unavailability
of complete alternative systems.

      Other issues that need to be addressed-are the Water Act, and the
requirements on waste water treatment plants.  There is not enough experience
in these areas -to sufficiently handle all the requirements..

      Dr. Schiegl then gave a summary of experiences of Siemens.  He discussed
a comparison of the environmental impacts of  chlorinated solvents and aqueous
cleaning.

      Chlorinated        .                      Aqueous

      - Volume of water is small               - Water waste treatment
      - Safe handling required tech.           - Batch treatment
        knowledge                              - Concentration by ultra
                                                 filtration
      - Sludge handling                        - Sludge handling

    '  He compared the operating costs for the solvent process with those for
the new aqueous process in a printed circuit board operation.

                                               Actual       Normal

      Maintenance                                71           59
      Electrical                                  8           12
      Product                                   205          135
      Waste Disposal                  •          128           46
            Total                               412          252
            DM/sq.m. of PCB                      3.15          2.52

      Mr. Herring of Duerr Equipment Company:

      Mr. Herring summarized the availability of equipment that will use the
solvents that are allowed under the new emission laws with their very tight
limits.   First, he discussed the availability of very tight, degreasers that
will use solvents, allowed under the new emission limits.  He explained how


                    * 1994 UNEP SOLVENTS.  COATINGS, AND ADHESIVES REPORT-*
                                     E-22

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the equipment works and minimizes any emissions to the environment and
protects the worker from exposure to the solvent vapours.  Since 1985, they
have sold 500 degreaser units.

      Mr. Herring also detailed the aqueous equipment which his company makes,
50 of which have been sold since 1988.  Today, 75 percent of the cleaner
machines he makes are aqueous and 25 percent are solvent-based.
                                                     "\
      Mr. Herring said that it was not possible to replace all the equipment
in two years.  He does not think hydrocarbons are ready yet and there is
currently no hydrocarbon equipment.  It takes approximately one year to
deliver the equipment after the,order is received.

      A discussion period followed the presentations.

      Prof. Nader pointed out that the German law did not undergo any
technical review, and was a political action.  German companies will have to
deal with the two laws, the CFC/Halon regulation and the 2 BImSch V
regulation.  Industry will either need to seek local exemptions under these
laws, or use the materials allowed under the BiMSch requirements (i.e., using
other chlorinated solvents with extremely,low emission levels).

      Other alternatives that the German industry can use are to search 'for
and implement alternative materials, although the short time frame will not
allow for much of this.  Importation of products containing or manufactured
with ozone depleting substances is not restricted in any way so that adhesives
and glues can be formulated outside of Germany, then imported for use in
Germany.  Also, manufacturers can have parts shipped out of the country for,
processing such as cleaning and then shipped back for installation.

      Summary comments.

      Steve Anderson - Chairman,Solvents Committee:  Equipment manufacturers
need to work hard to make the changes in Germany.  They should expand
manufacturing capability to meet the short term needs of the German situation,
then be positioned to help the rest of the world.  The German industry should
organize into expert teams and make their expertise available to the rest of
the world after they complete the German phase-out.

      Dr. Schiegl:  A 1994 phase-out would have been hard to meet, but
industry would have pushed hard to meet it.  The 1992 date is out of range
since it will take about five years to make the required changes.  Germany  is.
further ahead than most countries because they have had, for some years,
aggressive regulations on solvents and companies have programs in place to  try
to eliminate their use.
                                                          »
      Mr. Gabelmann:  Four to five years is needed to convert a challenging
and difficult application.  Smaller companies are not sure if they can meet
even that schedule.  German industry may need to send products to foreign
countries and will need to seek exemptions under local regulations.

      Mr. Romple:  A lot of information needs to get out to the smaller
companies.  They need time to think about and react  to the regulations.  What
will happen at this time is unknown.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      E-23

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      EEC laws give standard requirements for the community and member
countries and can be very stringent on environmental matters.  Sweden,
although not a member of the EEC, did not have an equipment shortage  during
their phase, but the product split in Sweden is different to Germany  and  other
European countries.  Trichloroethylene dominates the metal cleaning sector
with 1,1,1-trichloroethane having a very small share, due mainly  to the strong
position of the indigenous trichloroethylene producer.  Ninety percent of
telecommunications allowed for relatively easy substitutions by "no clean"
fluxes.  In Germany, much of the CFC-113 in use is for precision  and
mechanical cleaning which is more difficult to substitute.

      General summary comments of the session:

      •     Adhesives and fine line space circuit boards and other specialized
            uses will be problem areas.

      •     Aggressive German phase out will shift some production to other
            countries and/or lead to exemptions.

      •     Notification of the large numbers of users is critical,
            information on know-how and engineering is needed for smaller
            users.

      •     There may be a shortage of experts to deal with the problems.

      •     There may be a shortage of supply in new equipment.   Dr.  Anderson
            expressed confidence that equipment supplies will be  able to  meet
            the challenge.

      Evening Session:

      A brief special evening meeting was held to accommodate a last  minute
request of the Japan Alcohol Association.  This association has been
conducting tests for the comparison of cleaning with ethanol and.ethanol/water
mixtures as alternatives to CFC cleaning.  The special delegation was
represented by association members, producers, and an equipment supplier.
They presented preliminary data showing effective cleaning using  alcohols,
chiefly ethanol.  The study so far indicates that alcohols and blends are
effective cleaners; one must have the proper equipment and deal with  water
contamination.  They have additional work underway to help further define
their process and applications areas.
                    * 1994 UNEP SOLVENTS, COATINGS. AND ADHESIVES REPORT *
                                     E-24

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                   APPENDIX F

SUMMARY OF TESTING  PROGRAMS FOR ALTERNATIVES
        IN THE ELECTRONICS INDUSTRY IN
SWEDEN, UNITED KINGDOM, AND  THE UNITED  STATES
   * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                      F-l

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TABLE  F-l.   COMPARISON OF US,  UK,  AND TRE INTERNORDIC  CLEANING  OPTIONS
                           EVALUATION  PROGRAMMES


Collaboration
Timescale Monitor


TEST VEHICLE
Substrate


Components

Max I/O
Min Pitch
Min Stand-off
Height
Flux

Soldering
Method
ASSEMBLY

CLEANING
OPTIONS DATA >
CFC
Semi-Aqueous
HCFC
Aqueous
Low Solids Flux
Com. Atmosphere
Alcohol








IPC/DOD/EPA

Voluntary
1988-1992/3
IPC, etc.

FR4


LCC

68
0.050"
0.005" (fixed)

RA

VPS; Wave

Multi-site
Multi-line


(1989) Phase 1
(1991) Phase 2
(1991) Phase 2
(1993) Phase 3
(1993) Phase 3
(1993) Phase 3
i.
\







UK

Contractual
1990-1992
DTI/MOD

SMT:FR4
Mixed Tech : FR4
SMT : Ceramic
PLCC; QFP; SOIC
chip capacitors •
160
0.025"
.
•
RA;RMA;No
clean
IR; Wave

Central
Single Line


1992
1992
1992
1992
1992
1992
1992







, ' .
UK

Contractual
1990-91
NPL

FR4


QFP; PLCC

100
0.025"
0.003"

RMA; Water
soluble
IR; Wave

Multi-site
Single Line


1990
1990
1990
1990
1991
-
1990


. »




TRE
Internordic

Contractual
1988-92
IVF Sweden

FR4


LCC, PLCC, DIL,
SOT,. chip capacitor
68
0.025"
= 0.003"

RMA, No clean,
OA
VPS, IR, Wave

Multi-site



Complete
Complete
-
-
Complete
Complete
Complete
1992: Off-shelf
commercial
products, water
cleaning micro-
emulsion storage,
handling, white
residues
                 * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                     F-2                   ,

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                                   APPENDIX G

                       LIST OF MEMBERS OF ICOLP AND JICOP

              INTERNATIONAL COOPERATIVE FOR OZONE LAYER PROTECTION
                             MEMBERS  LIST OF ICOLP
AT&T

British Aerospace  .

Ford Motor Company

Hitachi Limited

Honeywell

IBM Corporation

Mitsubishi Electric  Corporation

Motorola Corporation

Ontario Hydro

Northern Telecom

Texas Instruments

Toshiba Corporation
                    *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       G-l

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                            MEMBER'S LIST OF JICOP

                   (as of Sept 1994, in alphabetical order)



Aerosol Industry Association of Japan

All Japan Laundry and Drycleaning Association

Association of Methyl Bromide Industry Japan

Association of Polyurethane Foam Industry

Chemicals Inspection & Testing Institute, Japan

Communications Industry Association of Japan

Electronic Industries Association of Japan (EIAJ)

Electronic Materials Manufacturers Association of Japan

Extruded Polystyrene Foam Industry Association

The Federation of Electric Power Companies

Federation of Electroplating Industry Association, Japan

The Federation of Pharmaceutical Manufacturers' Associations of Japan

The Glass Manufacturers Association of Japan

Heat Treatment Trade Association of Japan

High Expanded Polyethylene Foam Industry Association

Industrial Pollution Control Association Japan

Japan Adhesive Industry Association

Japan Air Soft Gun Association               .

Japan Alcohol Association (JAA)

Japan Aluminium Federation

Japan Association for Hygiene of Chlorinated Solvents  (JAHCS)     \

Japan Association of Refrigeration & Air-Conditioning  Contractors

Japan Association of Wholesales for Laundry and Drycleaning

Japan Auto Parts Industries Association  (JAPIA)

Japan Automobile Manufacturers Association, Inc.  (JAMA)
                   *  199* UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      G-2

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Japan Automobile Service Promotion Association  (JASPA)

The Japan Bearing-Industrial Association  (JBIA)

Japan Business Machine Makers Association  (JBMA)

Japan Camera Industry Association
                                              •s '
Japan Chemical Importer's Association  (JCIA)

Japan Chemical Industry Association

Japan Chemical Industry Ecology-Toxicology &  Information Center  (JETOC)

Japan Clock & Watch Association  (JCWA)

Japan Container Association

Japan Cosmetic Industry Association

Japan Dyestuff & Chemical Industry Association

Japan Electric Measuring Instruments Manufacturers' Association  (JEMIMA)

The Japan Electrical Manufacturers' Association  (JEMA)
                                          I
Japan Electronic Industry Development Association  (JEIDA)

The Japan Fire Extinguishing System Manufacturers' Association

Japan Flon Gas Association

Japan Industrial Conference on Cleaning (JICG)

Japan Information Service Industry Association  (JISA)

The Japan Iron and Steel Federation (JISF)

Japan Laundry and Drycleaning Conference  (JLDC)

Japan Metal Sash Institute                    •

Japan Metal Siding Industry Association

Japan Metal Stamping Association

Japan Petrochemical Industry Association  (JPCA)

Japan Prefabricated Freezer and  Refrigerator  Industrial Association

Japan Printed Circuit Association

The Japan Refrigeration and Air  Conditioning  Industry Association  (JRAIA)

Ja'pan Semiconductor Parts Industrial Association


                   *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      G-3

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Japan Soap and Detergent Association

The Japan Society of Industrial Machinery Manufacturers (JSIM)

Japan Surfactant Industry Association

The Japan Valve Manufacturers' Association

Japan Wood Preservers Industry Association (JWPIA)

Japanese Association of Refrigeration

Japanese Consumers' Co-Operative union (JCCU)

The Japanese Electric Wire &  Cable Makers'  Association

National Federation of Petroleum Commercial Association

Research Institute of Innovative Technology for the Earth,  Department

      for the New Generation  Refrigerant  Research

The Society of Japanese Aerospace 'Co.,  Inc.

Ultrasonic Manufacturers Association
                    *  1994 UNEF SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      G-4  .

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                                 APPENDIX H

    ANALYSIS  OF CURRENT AND FUTURE  PRODUCTION OF CARBON TETRACHLORIDE

    (Reproduced from  the  1994 Report of the UNEP Aerosols,  Sterilants,
Miscellaneous Uses,  and Carbon  Tetrachloride Technical Options  Committee)
                * 1994  UNEP SOLVENTS,  COATINGS,  AND ADHESIVES REPORT *
                                  •   H-i

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VI.   CARBON TETRACHLORIDE  (CTC)
6.1    Introduction

Carbon tetrachloride (CTC) is a heavy, colourless liquid at normal temperatures and
pressures (boiling point 77"C).  It is non flammable, miscible with most organic liquids
and is  a powerful solvent.  In the past CTC has been used for charging fire extinguishers,
as grain insecticide fumigants, as an antihelminthic agent (especially for the treatment of
liver fluke in sheep) as a solvent in the rubber industry and most commonly as a dry
cleaning solvent and metal degreasing solvent. It has been almost completely supplanted
in the  developed countries by less toxic and often more effective materials for all these
uses but it is believed to still be used, for example as a grain fumigant in some
developing countries.

CTC is the most toxic of the chloromethanes (10 ppm by volume in air threshold limit as
a maximum safe concentration for daily 8hr exposure [26]).  It is harmful if swallowed,
inhaled or absorbed through the skin and -its vapour decomposes on contact with flame
or very hot surfaces to give off phosgene and other toxic products. CTC vapour or mist
is irritating to the skin, eyes, mucous membranes and upper respiratory tract.  Exposure
can cause stomach pains, vomiting, diarrhoea, nausea, dizziness and headaches, and
damage to the eyes, liver and kidneys.

CTC is produced primarily as a feedstock tor CFC 11/12 production  in which it is
converted to the respective CFC by replacement of either one or two chlorine atoms by
fluorine atoms,  normally in  a process where CTC is reacted with hydrogen fluoride (HF)
in the presence of a catalyst.

There  are a number of other minor feedstock uses of CTC, in which the CTC is entirely
transformed during the process, which are permitted under the Montreal Protocol.
These  feedstock uses include the production of key pharmaceutical and agricultural
chemicals and use as a catalyst promoter in oil refineries.

It is important to distinguish between dispersive and non-dispersive uses of CTC. There
are a number of possible ways of interpreting what is and what is  not a dispersive use of
CTC (and other controlled substances).  For the purposes of this report' the following
definitions have been applied:

   A dispersive  use is any use of CTC in which all or some part of the CTC is emitted to
   the  environment, for example laboratory use (eg. spectroscopy), inert reaction solvent
   (eg. pharmaceutical manufacture).                              ,                .

   A non-dispersive use is any use in which  the CTC takes part in the reaction and is,
   thereby transformed into another chemical, for example CFC manufacture, catalyst
   reforming, reagent use.
                  * 1994 UNEP  SOLVENTS,  COATINGS,  AND  ADHESIVES  REPORT *
                                        H-2

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 There is a grey area where the CTC may react partially in the process.  This is claimed
 to occur during the manufacture of chlorinated rubber.

 A very small percentage of CTC production is used for dispersive uses.  The main
 dispersive use, is as a solvent for materials undergoing chlorination, the majority being
 used in the production of chlorinated rubber and small quantities are used as a process
 solvent in the pharmaceutical industry.  In certain circumstances, it is possible to make
 such uses virtually non-dispersive by the application of modern technology and thermal
 oxidation processes.

 A small but important dispersive use of CTC is the laboratory use of CTC for example, a
 solvent for infra-red analysis  of oil.. Dispersive  uses are described in more detail  below.

 Inadvertent production of CTC  also arises in some important industrial processes.  For
 example,  in the production of chlorinated solvents, chloromethane and vinyl chloride. In
 most cases the CTC is either recycled and destroyed within the production unit or is used
 as a feedstock for production of another chlorinated derivative. For example, CTC
 produced in vinyl chloride monomer plants is often used as a feedstock in the production
 of either  trichloro- or tetrachloroethylene.  Alternatively, CTC may be thermally oxidised
 to produce either hydrogen chloride(HCl) or chlorine which is then recycled for use in
 chlorination or oxychlorination processes.  Small trace levels of CTC will remain in the
 final chlorinated derivative.  It is estimated that these levels  do not exceed 100 ppm and
 are generally  10 ppm. This issue is under review by the United Nations Environment
 Program  (UNEP)  Technology and Economic Assessment Panel.
 6.2       CTC Production and Consumption

 CTC is normally produced by the high temperature chlorination of propylene or
 methanes, usually known as chlorinolysis.  Other starting materials include vinyl chloride
 (VC) by-products, ethylene dichloride, propylene dichloride, chloromethane by-products
 and  propylene oxide by-products.  CTC can also be produced by chlorination of carbon
 disulphide.  Production facilities for CTC usually produce CTC alone or CTC and ^
 perchlorethylene as joint products - these latter facilities can usually be tuned to produce
 either 100% perchlorethylene or 100% CTC by recycling within the plant.

The global production data for CTC has not been reported. It is anticipated the data
 collected  under the Montreal Protocol will  provide information on production for non-
 feedstock uses and consumption in the future. It is possible to estimate total CTC
 production for CFC production by using the following formula:

                CFC  11 produced x 1.14*  = CTC consumed

                CFC  12 produced x 1.30*  = CTC consumed        .

 ( (*): These figures are average values and for guidance only)
                   * 1994 UNEP SOLVENTS,  COATINGS,  AND ADHESIVES  REPORT
                                         H-3

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By using data provided by the Alternative Environmental Acceptability Study (AFEAS)
[Production, Sales and Atmospheric Release of Fluorocarbons through 1992, Alternative
Fluorocarbons Environmental Acceptability Study 1993 [3], it is possible to make the
following estimates (in tonnes).
Year
1990
1991
1992
CFC11
232,916
213,486
186,373
CTC*
265,524
243,374
212,465
CFC 12
230,950
224,805
216,262
CTC*
300,235
292,247
281,141
Total CTC
565,759
535,621
493,606
AFEAS estimate that between 18-31% of 1991 production of CFC 11/12 is unreported in
the above data. Data are not included in the above Table for the following countries,
Argentina (in part), States of the former Commonwealth of Independent States, the
Czech Republic, the Slovak Republic, India, China, Romania and South Korea.

The most comprehensive data worldwide on CTC production and consumption is that
published by the Japanese Association for the Hygiene of Chlorinated Solvents (JAHCS).
These are summarised below.
               Production and Consumption of CTC in Japan (tonnes)
Year
Production
Import
Export
Consumption
CFC
Feedstock
Miscellaneous
1988
60,790
47,996
16
108,770
101,692
X
7,078
1989
57,530
44,219
37
101,712
93,135
8,577
1990
52,039
19,868
516
71,391
63,305
8,086
1991
51,475
17,013
2,200
66,288
58,595
7,693
1992
49,539 ,
2,481
2,648
49,372
44,449
4,239
                    1994  UNEP SOLVENTS,  COATINGS,  AND ADHESIVES REPORT *
                                       H-4

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Miscellaneous uses described in the Table include other feedstock uses of CTC.
Miscellaneous Use of CTC in Japan is estimated to be about 6000 tonnes.  Dispersive
uses in Japan in 1989 was approximately 7600 tonnes.  The largest portion of this volume
was consumed by the chlorination of rubber and poly-olefin which accounted for some
3000 tonnes in  1989.  Producers are still working on a feasible substitute with phase out
of CTC expected by the end of 1994.

Inadvertent CTC production is not reported. This topic is dealt with separately by the
Technology and Economic Assessment Panel. It is anticipated that this material will
continue to be produced.  The majority will be recycled or destroyed with small
quantities being isolated and purified to be used as feedstocks for other chlorinated
hydrocarbon processes or as feedstock for the production of Pharmaceuticals and
agrochemicals, as permitted under the Protocol.
6.3      Non-Dispersive Uses of GTC

The main use of CTC is as a feedstock for CFC 11 and 12 production. It can be
estimated that 95 to 97% of CTC production is used in this manner.  Reported world
wide production [3] of CFC 11 and 12 has declined from 748,511 metric tonnes in 1986
to 402,635 in 1992 with a corresponding decline in CTC production.  This will decline
further as CFC phase out is approached.

It is possible to hydrogenate CTC to chloroform and this may become a way of disposing
of involuntary CTC production. No operating full-scale processes are known.

CTC is also used as a feedstock in the manufacture of a number of important fine
chemicals, agrochemicals and pharmaceuticals.  Products manufactured include the
pesticides chloranthil, DCPA, picloram, permethrin and cypermethrin, the drugs AZT
and dalacin  and the production of the important intermediate trityl chloride.

CTC is used as a 'catalyst sweetener' in the petrochemical industry where its role is to
maintain the presence of chloride ions on the catalyst surface.  The CTC is destroyed
within this process but it is likely that non-ozone depleting substances such as
tetrachloroethylene or ethylene dichloride could be, and are used to provide this a similar
effect.        .                       ;                                              .

Another small volume application is in the stabilisation of liquid sulphur trioxide for
transport and storage.  It is claimed that the CTC reacts with the SO3 in  situ to form the
stabilising agent as shown in the reaction below:

   2SO3  + CC14  	>   COC12 + S2O5C15
                   * 1994 UNEP  SOLVENTS,  COATINGS,  AND ADHESIVES REPORT *
                                        H-5

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 Reagent

 CTC is an important reagent in several reactions. When used as a reagent CTC is
 consumed or chemically altered so this can be considered a non dispersive use.

 Supercritical CTC reacts with metals such as niobium and tantalum to form chloride
 salts. This reaction can be used to purify the valuable metals from their oxides.

 CTC is used in free radical reactions and will add across double bonds to functionalise
 olefins [27].  For example, CTC adds across the double bond in ethyl vinyl ether to give
.the functionalised ether.

 Alcohols can be converted into chlorides using triphenyl phosphine and CTC under mild
 conditions [28].  A similar procedure can be used to open epoxides to give cw-vicinal
 dichlorides [29], and to chlorinate enolisable  ketones and ureas [30].  In general  there
 are many other chlorinating agents for these  purposes but in some cases this reaction
 cannot be substituted.

 Aldehydes, ketones and some esters react with CTC in the presence of
 triphenylphosphine, tris(dimethylamino)phosphine, and other reagents, to give the
 dichloromethylene derivative [31]. CTC is often used as the solvent as well as the
 reagent in this reaction.

 The radical degradative chlorination of carboxylic acids and acid chlorides using CTC
 and  2 - mercaptopyridine - N - oxide has been  used to prepare, otherwise difficult chlorp
 compounds from the  corresponding  carboxylic acids [32].

 Other useful reactions using CTC as a reagent  include its -use as a trichloromethylating
 agent in Friedel-Crafts  type reactions. [33] and as a chlorine source in the palladium
 catalysed  chlorination of trialkylsilanes to give trialkylsilyl chlorides [34].

 In all cases, at the research level, the world consumption of CTC as a reagent is very
 small compared with  other uses.
6.4      Dispersive Uses of CTC

CTC is classified by most regulatory authorities as a 'possible' human carcinogen, and as
such its use in dispersive applications is small in countries with strict occupational health
and safety  legislation.  These regulations require that most applications of CTC are
totally enclosed with recovery and recycling equipment.
                     1994 UNEP SOLVENTS,  COATINGS,  AND ADHESIVES  REPORT
                                         H-6

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 6.4.1     Chlorination Reactions

 The largest use of CTC outside CFC production is as an inert solvent in chlorination
 reactions.  Other non-ozone depleting chlorocarbons are not suitable for this application
 as they are either not  inert  or do not have the required solvency properties.  Indeed, in
 some cases, for example the manufacture of chlorinated rubber, there is evidence that
 CTC plays an essential role as  a reagent in chlorination reactions with a small percentage
 reacting, and thereby being destroyed in the process.  Considerable work is being carried
 out to identify alternatives , and in a number of cases to minimise CTC emissions. In
 general, CTC is recycled and losses are low.  The average recovery efficiency is about
 98%.  In new-plants recovery rates exceeding 99.9% can be realised. With modern
 technology and the incineration of CTC containing process residues, it is possible to
 reduce emissions to a  practicable minimum.  In such circumstances such applications
 could be considered as 'non-dispersive' and with appropriate monitoring could be
 permitted to be continued after the CTC phase-out.

 The major products where CTC is used as a solvent are chlorinated ethylene vinyl
.acetate copolymers, chlorinated polyethylene and chlorinated polypropylene, which are  '
 used principally in marine and  weatherproof paints (EEC use of CTC in chlorinated
 rubber manufacture in 1989 was approximately 2300 tonnes, but is anticipated will have
 reduced significantly since 1989).
 There is a trend away from chlorinated rubber paints with aqueous and other polymer
 based systems becoming available  although for some applications  it is extremely difficult
 to find  alternatives  as  no other paint system offers all the superior  properties which are
 combined in chlorinated rubber.  In many countries, specifications and standards demand
 the use of chlorinated  rubber systems which have been subjected to rigorous and long
 term testing procedures to guarantee  their efficacy in  use.

 In these areas the alternatives will have to be subjected to similar testing regimes prior  to
 their adoption.  By  the end  of 1995, Japanese chlorinated  rubber producers will have
 moved  to alternatives.

 CTC is used as an inert solvent in chlorination reactions for the manufacture of a
 number of pharmaceutical products or intermediates,  such as the  drug, Ibuprofen.  In
 certain  circumstances other  inert solvents such as chlorobenzenes  may be appropriate but
 these will require pharmaceutical approval which  can  take up to 5 years.
                                                         l '
 It is believed that CTC is still used as a cleaning solvent in parts of Eastern Europe,
 India, South East Asia and USSR and this view is supported by measurements of
 atmospheric CTC concentrations.  However, no data on CTC use in this region have
 been obtained.                                            .

 Another application is the use of CTC in the palm oil industry in  South East Asia as an
 extractant.  Consumption data are not available.
                     1994 .UNEP SOLVENTS,  COATINGS,  AND  ADHESIVES REPORT
                                         H-7

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6.4.2     Laboratory Uses

The unique physical and chemical characteristics of CTC have led to its adoption
worldwide as a laboratory solvent for many different applications.  CTC is used for
routine chemical analysis for the operation and environmental control of many chemical
manufacturing plants.  It is also used for the research and development of technologies
and products in most laboratories throughout the developed and developing world. As a
result of its unique characteristics there are few alternatives which are available.

Some examples of CTC laboratory use include:

   •     extraction solvent
   •     reaction solvent
   •     eluent for chromatography
   •     spectroscopy
   •     analysis standard

Current consumption rate worldwide is estimated to be less than  1000 tonnes per annum.
The majority of analytical methods using CTC are documented standards which will
require changing through individual national and international standards organisations.

CTC used for laboratory uses is distributed to laboratories worldwide through  a totally
different route  than the majority of applications discussed in this chapter.

In most circumstances  it is marketed as ultra pure grade or as spectroscopic standards in
containers which vary in volume from a few hundred millilitres to a size of five litres.  In
most analytical techniques only a few millilitres is used per analysis.

Extraction  Solvent

CTC is a powerful non polar solvent for many organic compounds and its use  is specified
in many national and international standard procedures. With the range of solvents
available for extractions, its use for this purpose could cease immediately in the majority
of cases with little disruption to normal laboratory procedure, were it not for these
standards.  Because of the known toxicity of CTC it  is generally used as an extraction
solvent only as  a last resort.

One example of the use of CTC as an- extraction solvent used in an analysis standard  is
the Wijs method for determining the "iodine value",  a common parameter measured in
edible  oils.   The test involves dissolving the oil or fat in CTC, adding standardised  Wijs
solution, then after the reaction is complete adding potassium iodide solution and
titrating the free iodine with sodium  thiosulphaie.  CTC is used as the solvent  because it
is inert to Wijs  solution.  Alternative methods to the Wijs procedure will need to be
developed in order to cease this dispersive use  of CTC.
                     1994 UNEP SOLVENTS,  COATINGS,  AND ADHESIVES  REPORT

                                         H-8

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Inert Reaction Solvent

CTC is used as a inert reaction solvent in several useful chemical procedures.
Regioselective bromination reactions using yV-bromosuccinimide (NBS) and regioselective
chloririations using TV-chlorosuccinimide (NCS), are usually carried out in Ci'C. Although
other solvents have been used for this type of reaction it has been shown that  the
regioselectivity of NBS and NCS reactions can be significantly  altered by changing the
solvent.[35].

CTC and the chlorofluorocarbons (CFCs) are common solvents for fluorination reactions
using molecular fluorine or fluoroxytrifluoromethane (CF^OF). Fluorine is a highly
reactive gas that often breaks carbon chains into smaller units, a side reaction  that
sometimes becomes troublesome  in chlorinations as well.  Substitution of other solvents
in these reactions would be difficult. Carbon tetrafluoride may be too low boiling in
some cases and higher perfluorinated hydrocarbons would probably suffer attack by
molecular fluorine.  Some such reactions can be carried out using nitrogen as solvent at
low temperatures.

Eiuent for Chromatography

CTC has found use as an eluent for gas chromatography because it is relatively volatile
and is a good  solvent.  Again these physical features are found in many  other common
laboratory  solvents  and therefore, CTC use could cease in the  majority of cases for this
purpose. In some cases, its use as a eluent  may be stipulated for analytical procedures
and substitutes will  require regulatory approval.                  :

Spectroscopy

Samples for infra-red (ir) spectroscopy analysis can be prepared  in various ways.
Gaseous samples can be introduced directly into a cell containing ir transparent windows.
Liquid samples are  often run as thin films between two ir transparent plates, of which
sodium chloride and potassium bromide plates are the most common. Spectra of solids
may be obtained by grinding  the solid in a drop of liquid paraffin (Nujol) and  then
pressing the sample between  two plates as for liquids.  Nujol absorbs ir  in the  C-H region
so alternative  methods must be used if this region is important. Solid samples may also
be ground  with potassium bromide and pressed into thin, disks and this method often
gives  the most satisfactory ir spectra for both solids and liquids.

Molecular  interactions of interest may change markedly from the solid state or neat
liquids to those found in solution, and ir  spectra taken in dilute solutions of non polar
solvents are normally .better resolved. For these reasons, ir spectra are  sometimes
recorded in a  sample cell where the analyte is dissolved in a suitable solvent.  Obviously,
the solvent must not significantly absorb  ir radiation in the region of interest.  CTC  is one
of the best solvents for this purpose because it only absorbs ir radiation  in narrow bands
and in areas that  are  usually  of little interest.  Other'solvents which may be used include
alcohol free chloroform and carbon disulfide.          .
                     1994 UNEP SOLVENTS,  COATINGS,  AND ADHESIVES REPORT
                                         H-9

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 CTC is used in certain applications as a transparent spectroscopic medium in ultra-violet
 spectroscopy, which is usually effective for the identification of substances that have an
 absorption band in the ultra-violet range,  for instance, nitrogen or aromatic compounds.

 Trace components which have fluorescence  or substances which have an affinity with
 appropriate fluorescent agents can be identified in low concentrations by fluorescence
 spectroscopy. CTC is used as a non-fluorescent carrier solvent.

 Nuclear magnetic  resonance (n.m.r.) spectroscopy is used extensively for' the
 identification of substances which have complex molecular structures. CTC is used as the
 most appropriate solvent in many cases due to  its solvency characteristics and unique
 chemical structure. In some circumstances deuterochloroform is an effective  substitute.
                                                                  f-
 The quantities of CTC used for  these purposes are  small; usually requiring 1  ml or less
 for each sample. CTC is very useful for this purpose and for specialist applications in
 most cases it would be difficult to substitute.

 Analysis Standard

 Carbon tetrachloride  is-also used as an analysis standard in various analytical procedures
 [36].  One such example is as a component of the Karl Fisher reagent, which is used to
 determine the water content of a variety of substances. In this case a number of
 alternative reagents and techniques are currently under development.

 CTC is  used as a calibration standard for  the monitoring of atmospheric concentrations
 of CTC and similarly  for the monitoring of CTC concentrations in water. There is
 obviously little space for alternatives tovCTC in these  applications.

 6.4.3     Agricultural and Veterinary Uses                 •

 CTC is  known to have been used in two main areas:  as an  insecticide fumigant,
 especially in stored grain and cereal products; and as  a veterinary antihelmintic agent,
 especially for the treatment of liver fluke in  sheep.

There seems to be no documented evidence of either use currently, although there are
 suspicions that CTC is still used  in certain countries because it is cheap.  Amounts are
 likely to be small and declining.

CTC was used as a bulk grain fumigant in Africa up to 10 years ago.  Currently its use
would be very limited at the individual farmer level.

CTC is  possibly still used as an anti-fluke agent in Nepal and Sudan, but generally there
is worldwide distribution of much better drugs that are not expensive.
                     1994  UNEP SOLVENTS,  COATINGS,  AND  ADHESIVES REPORT *
                                        H-10

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6.4.4      Chlorine Production

CTC is used in chlorine production to prevent the build up of potentially explosive
concentrations of nitrogen trichloride
The NC1? is formed by reaction between chlorine and traces of nitrogen in the original
raw material, brine (NaCl), during the electrolytic process which produces chlorine and
caustic soda (NaOH).

A number of companies pass the chlorine which contains the1 trace levels of NCl^ through
CTC which dissolves out the potentially explosive , product. The  CTC is then destroyed. by
incineration. Because of the strict guidelines pertaining to the handling of chlorine this
process is totally enclosed.

There are a number of alternatives which can be adopted to prevent the build up of  .
NC1V These vary depending upon the source of the nitrogen in  the brine and include:

a) Removal of nitrogen from the brine prior to chlorine production

                •     if in the form of ammonia, acidify and strip to  remove
                      if ferrocyanide-based destroy with chlorine
               .•     removal by raising temperature of brine to >100°C.

b) Destroy NC13

          •      use UV-light reactor  to destroy NCl-^.

A number of alternatives exist for the destruction or prevention of formation of NCl^ in
chlorine production that could be adopted over the next few years, although probably not
within the current CTC phase out schedule.  In many circumstances where the CTC
containing residues are incinerated, the use may be considered as non-dispersive.
6.5      Options for Replacement

In some applications, no replacement for CTC will be required because either the
application is being phased out, or the CTC is chemically transformed during the process
or is completely destroyed or recycled. These applications are described in Section 6.3
above.

No general substitute has been identified for CTC, although progress in certain specific
cases has been made.  In its application as an inert solvent  in chlorination  reactions no
substitute has yet been identified.  It should be possible by application of containment
technology to minimize CTC emissions.  It should be noted that where CTC is used as a
inert reaction solvent for chemical production any change may require time for regulatory
approval.  With reduced CTC production  as a result of CFC phase out, there may be
problems in obtaining CTC of sufficient purity for these applications.

                   * 1994 UNEP SOLVENTS,  COATINGS,  AND ADHESIVES  REPORT  *
                                        H-ll

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6.6      Recovery anu Recycling
In tVie majority "f c?ses CTC "seH as an r^rt "eaction "oh'^nt is recrve-~d in the
production process and re-cycled in-house.  When recycling is inappropriate, for example,
when the CTC becomes unsuitable for continued use, it is available for reclamation or
destruction.                                                                 -

Where destruction follows use of CTC in a totally enclosed systems, emissions of CTC to
the environment can be considered as insignificant.
6.7      Emission Minimization

It is essential that all emissions of CTC are minimised during manufacture and use.  To
provide additional guidance to facility operators, a "Code of Good Housekeeping" has
been prepared, based on a similar code prepared by the UNEP Destruction Technical
Advisory Committee.  This code is also intended to provide a framework of practices and
measures that should be adopted at facilities undertaking the use  of CTC.

Not all measure-s will be appropriate to all sifuations and circumstance"  and as with any
Code, nothing specified should be regarded as a barrier to  the adoption of better or s
more effective measures if these can be identified.  The suggested Code of  Good
Housekeeping is described in Appendix 6.
6.8      Developing Country Perspective

Some developing countries have small chlorinated rubber manufacturing facilities. It is
believed that at present, one or two other facilities using outdated technologies are being
re-installed or are in the planning stages.

The  dispersive use of CTC in developing countries is small and is principally for-cleaning
applications.  Alternatives already exist and are widely available as discussed in the
UNEP Solvents, Coatings and Adhesives Technical Options Report.  In those countries
that  continue to produce  CFCs it is likely that CTC will still be used for this and other
applications.
6.9      Summary and Conclusions

World production and consumption of CTC will reduce substantially as manufacture of
CFC 11 and CFC 12 is reduced and phased out.  Some inadvertent production will
continue as a result of other chlorinated processes.  Control technology will keep
emissions of this material to a minimum.
                  * 1994 UNEP  SOLVENTS,  COATINGS,  AND  ADHESIVES  REPORT *
                                       H-12

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A number of important chemical processes will continue to use CTC as a feedstock in
which the CTC is either destroyed or chemically transformed. These processes will
include chemical feedstock for pharmaceutical-and agrochemical production, 'catalyst
sweetening' and sulphur trioxide stabilisation. Total use in.these areas is estimated to be
less than 5000 tonnes per annum.

A number of alternatives, such as other chlorinated or inert solvents, have been identified
for certain uses of CTC as an inert solvent for chlorination reactions. Alternatives can
only be identified on a case by case basis.  In principle, by -the application of containment
technology and the use of thermal oxidation to destroy CTC-containing process residues,
CTC emissions can be virtually eliminated from these applications.  As a result total
usage should reduce  rapidly.

In these circumstances, the CTC use as chemical process agents is effectively non-
dispersive except for insignificant emissions.  A decision will be required by the Parties to
define and consider what control measures are appropriate for these applications.

There has currently been little effort in the development of alternatives to CTC for
analytical and laboratory applications.  Further, many users of CTC are unaware of its
role  in ozone depletion, contributing to the lack of development of alternatives.  A
number of national and international laboratory standards specify the use of CTC as a
solvent,  these will require amendment by the relevant authorities.

At this time the committee supports 'the concept  of a global exemption for laboratory
uses of CTC with appropriate controls as described in the March 1994 report of the
UNEP Technology and Economic Assessment Panel. A decision will be required by the
Parties on whether these analytical and laboratory uses  should be controlled and, if so, by
what mechanism.

REFERENCES
[3]    Grant Thornton Report 1993, Alternative Fluorocarbons Environmental
      Acceptability Study, August 1993.

[26]   Lewis, R. J., Sax's Dangerous Properties  of Industrial Materials, Vol. II, 8th Ed.,
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[27]   Friedlina, R. Kh., Velichko, F. K., Synthesis, 145, 1977.

[28]   Appel, R.,Angew. Chem. Int. Ed. EngL, 14, 801,  1975.

[29]   Isaacs, N.S., Kirkpatrick, D., Tetrahedron Lett., 3869, 1972.

[30]   Appel, R., Warning, K., Ziehn, K. D., Ber Deutsch-Chem. Ges., 107, 698, 1974.
                    1994  UNEP SOLVENTS,  COATINGS,  AND ADHESIVES  REPORT
                                       H-13

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[31]   Rabinowitz, R., Marcus, R., . J Am. Chem Soc., 84, 1312, 1962; Chapleur, Y., J
      Chem. Soc. Chem. Commun.,  7, 449, 1984;  Suda, M., Fukushima, A,. Tetrahedron
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[32]   Barton, D.H. R, Crich, D, iMotherwell, W.B., Tetrahedron Lett., 24, 4979, 1983.

[33]   Newman, M. S., Pinkus, A. G., J. Org Chem., 19, 978,  1954.

[34]   Citron, J. D., Lyons, J.E., Sommer, L.H., / Org Chem., 34, 638, 1969.

[35]   Offerman, ,W. and Vogtle F., Angew Chem. Int. Ed Engi, 19, 464 1980.

[36]   "Annual Book of ASTM standards", American Society for Testing and Materials,
      1991
                  * 1994 UNEP SOLVENTS,  COATINGS,  AND ADHESIVES  REPORT  *
                                    •   H-14

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                                   APPENDIX .1

         TOTAL  EQUIVALENT WARMING  IMPACT (TEWI)  OF SOLVENT ALTERNATIVES
      Total  Equivalent  Warming  Impact  (TEWI)  provides  an important tool in the
selection procedure  for alternative  cleaning  and drying technologies.
However, TEWI must not  be  the only criterion  when selecting the  cleaning,
drying, or other  technology  for a manufacturing proces's.   The  Alternative
Fluorocarbons Environmental  Acceptability  Study (AFEAS)  has provided a
methodology  to  calculate TEWI for wide  range  of available  systems.

      The selection  of  the best technology to displace  CFC-113 or  1,1,1-
trichloroethane (methyl chloroform)  must be specific to  the intended
applications and  will represent a .trade-off or balancing of several  key
parameters:  worker  safety (toxicity or flammability concerns),  investment,
operating costs,  energy efficiency and  reliability.  It  must also  consider a
series of environmental issues  (discharges to water or  landfill, local
environmental air quality  (smog) and global impact).

      This report has evaluated one  of  the selection parameters, TEWI,  for a
number of systems.   A" summary of the key findings  follows.

•     Solvent losses from the cleaning  equipment  are potentially lower than
      assumed in  the 1991 study, resulting in lower calculated contributions
      to TEWI.  This reduction  in emissions is possible  through  the  adoption
      of enhanced vapour recovery and improved/novel approaches  to materials
      handling  (e.g., freeboard dwell).  In some  cases,  the above  technologies
      can be retrofitted to  very modern existing  equipment,  with results
      almost comparable  to new  equipment.   However, such equipment will
      require careful operation.and  maintenance to sustain low emission rates.

•     The no-clean systems used for  the manufacture of printed wire  assemblies
      have the  potential for the lowest TEWI.   For metal cleaning,
      chlorocarbon-based systems (e.-g., perchlorpethylene,  1,1,1-
      trichloroethane)   have the potentially  lowest TEWI.   However,  these
      chlorinated solvent systems may be subject  to various national,  regional
      and/or local regulations  or emission limits  that may severely  limit  the
      use of these chemicals for cleaning  applications.

•     The perfluorocarbon (PFC)  system  studied has the highest TEWI.

•     While.they  use more energy per unit  of  work  (throughput), aqueous, semi-
      aqueous and alcohol systems generally have been shown to have  a  lower
      TEWI than hydrochlorofluorocarbon (HCFC)  and hydrofluorocarbon (HFC)-
      based systems because  emissions from aqueous, semi-aqueous,  and  alcohol-
      systems do  not contribut'e  to global  warming.
                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      1-1

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•     In the case of HCFC/HFC/PFC-based systems, the direct  effect caused by
      emission of the  chemical,  represents from 40 percent to  over 90 percent
      of the calculated  contribution to potential global warming.

      Future study  should assess the effects of variations in  equipment and
practices on TEWI and  estimate implementation time for alternative systems in
developing countries.
                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                       1-2

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                                      R-l

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                                       R-2

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                    *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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Kerr, Margaret G.   1988  (October  20).   "The CFC Challenge:  Conservation and
Elimination."  Speech  given  at the UNEP Conference, Hague,  Netherlands.

Kerr, Margaret G.   1988.   "Industry's  Position:   Another View".   EPA Journal

Kimel, F.   1988.  Adhesives  and Sealants.   Chemical Week.   March 16,  1988.
pp. 28-71.

Kirk-Othmer.  1983.  Encyclopedia of  Chemical Technology.   Published by John
Wiley & Sons, New York, NY.  p. 380.   v.  21.

Kurita, Hiroshi.  1991a.   Comments on the  September 1991 draft UNEP Technical
Options Report.

Kurita, Hiroshi.  1991b.   Comments on the  December 1991 draft UNEP Technical
Options Report.

Lambert, Leo.  1987 (April 17).   ICF  Incorporated interviews with  Leo Lambert
at Digital  Equipment Corporation, Tewksbury, MA.

Lambert, Leo.  1990.   Comments on 1989 UNEP Technical Options Report.

Landrock, A.H.   1985.  Adhesives  Technology Handbook.

Lea, C.  1988b.  A  Scientific  Guide to Surface  Mount  Technology.
Electrochemical  Publications Ltd., Ayr,  Scotland.

Lipiec, J.   1982.   Adhesives Age.  The Three-Pronged  Attack on Pressure-
Sensitives.  March  1982.

Linford, H.B.; Saubestre,  E.B.  1950  (December).   Cleaning and Preparation of
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                               't                                        t
Maletsky, A. and Villa, J.   1981.  Paper,  Film  and Foil Converter.   September
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Maletsky, A. and Villa, •J.   1984.  The Diversification  of  Hot Melt Adhesives.
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Manino.  1981.  Using  Waterborne  Adhesives to Bond Rubber  Assemblies.
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Manko, Howard.  1983 (August).  "New  Packaging  Techniques  Force  and
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Manko, Howard.  1986.  Soldering  Handbook  for Printed Circuits and Surface
Mounting.  Van Nostrand, Reinhold Company,  Inc.,  New  York,  NY.


                    * 1994 UNEP  SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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 Markenstein,  Howard.   1983 (April 1).   "Solder Flux Developments Expand
 Choices."   Electronic Packaging and Production,   pp.  39-42.

 Matisoff,  Bernard S.   1986.   Handbook of Electronics  Manufacturing
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 Matsui,  Shiegeo.   1991 (July).   Comments on the  first draft  1991 UNEP
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 Matsumoto,  T.,  "Degreasing and Cleaning of Vacuum Equipment,"  Ilvac Japan
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 McBryde, W.L.   1985 (June).   "Assembly Process and Equipment Requirements
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 McLaughlin Gormley King 1989.   Comments received from David  Carlson,  Manager,
.Chemical Division ft Environmental Affairs,  McLaughlin Gormley  King Company,  on
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 Mertens, Jim.   1991a  (August).   Comments on the'first draft  1991 UNEP
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 Midgely  1991.    "Worldwide Consumption of Methyl Chloroform" by P.  Midgely
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 Ming, K.   1989.   Comparison of  Freon with Water  Cleaning Processes  for Disk
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 by K. Mittal,  Plenum  Press,  New York,  NY.

 Mobjork, L.  and Olsson,  M.   1989.   FFV Aerotech,  Subcontractor to Swedish
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 Mocella, M.T.   1991 (April). ,  "The CFC-Ozone Issue  in Dry Etch Process
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 Modern Paints  and Coatings (MPC)  - No  author named.   1994a (April).   Radiation
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 Montreal Protocol on  Substances that Deplete the Ozone Layer.   1987.   Revised
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 Moreau, M.   1988.   UV Curing Cuts Time and Costs For  Solenoid  Manufacturer.
 Adhesives Age.  April 1988.  pp.  18-19.

 Morphy, J.S.;  Santosusso,  T.M.;  and Zimmer,  D.J.   1987.   Polymer Emulsion
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                    *  1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
                                      R-9

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Mullen, Jerry.  1984.  How to Use Surface Mount Technology.  Texas  Instrument
Publishing Center.  Dallas, TX.

Nemoto, Y.  1989.  Toshiba.  Presentation to  the UNEP  Solvents  Committee  in
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Niemi, Carol.  1991.  Comments on 1989 UNEP Technical  Options Report.

Nikkei Sarigyo Shinbun.  1989 (June 8).  Summary of article concerning  "ice
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Nikon.  1989 (May 24).  Japan.  Presentation  to the UNEP,Solvents Committee
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Nilsson, S.  1988 (November 3).  Ericsson Telecom AB,  Box 193,  S-641 22
Katrineholm, Sweden.  Letter (in Swedish).  Ref. SX/K  811 to National
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Nordin, N.O.  1988 (November).  Action Plan for a Freon Free Lubrication  of
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Northern Telecom.  1989.  Northern Telecom Limited, Mississauga, Ontario,
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NTP.  1984.  Annual Plan for Fiscal Year 1984.  DHHS.  Public Health Service,
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NUCON International, 1991.  Product Literature.

Oakite Products, Incorporated.  1988.  "Metal Cleaning Fundamentals,
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O'Driscoll, M.   1988.  Minerals in Adhesives  and Sealants:  Solving a  Sticky
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Ortho 1989.  Comments received from William L. Chase,.Jr., Manager,
Registration and Regulatory Affairs, Orhto Chevron Chemical Company, on "Costs
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Owens, J.   1990 (Sept.).  3M Company.  "Alternative Solvent for Fluorocarbon
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Patterson, K. and Hunt, D.  1989.  Newark Air Force Base, Aerospace Guidance
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Pawling, J.A.  1987.  Surface Mounted Assemblies.  Electrochemical
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PEI.   1983.  Pedco-Environmental Inc., Consulting Associates, Cincinnati, OH.
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                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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Phasex Corporation, 360 Merrimack St., Lawrence, MA 01843.

Prane, J.H.  1980.  Reactive Adhesives.  Adhesives Age.  August  1980!  pp.  35-
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Racquet, D.  1988  (September 22).  Phillips Manufacturing Company,  Chicago,
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Radian.  1986a.  Radian Corporation, Durham, NC.  "Evaluation of Potential
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Randall, F.  1988a (November 7).  Ramco Equipment Corporation, Hillside, NJ.
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                                                             v
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SEHO.  1988.  Seitz & Hbhnerlein, Kreuzwertheim, West Germany.   General system
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Skeisf,"Inc.  1987.  Adhesives, V:'  A Multiple Client Study.  October 1987.


                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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SNV 1990a.  Swedish Environmental  Protection Agency,  Solna,  Sweden.
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                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT
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                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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U.S. EPA.  1989c (June).  Communication from James Hemby, Global Change
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                     1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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Wenger, George and Munie, Gregory.   1988  (November).   "Defluxing Using Terpene
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                          \          '             .   .

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                    * 1994 UNEP SOLVENTS, COATINGS, AND ADHESIVES REPORT *
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