United States EPA-600/R-94-022
Environmental Protection
ABencv February 1994
<&EPA Research and
Development
PROCEEDINGS:
POLLUTION PREVENTION CONFERENCE ON
LOW- AND NO-VOC COATING TECHNOLOGIES
Prepared for
Office of Pollution Prevention and Toxics
Prepared by
Air and Energy Engineering Research
Laboratory
Research Triangle Park NC 27711
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EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the contents necessarily
reflect the views and policy of the Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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POLLUTION PREVENTION CONFERENCE ON
LOW- AND NO-VOC COATING TECHNOLOGIES
May 25 through 27, 1993
San Diego, California
Coleen M. Northeim and Ella J. Darden, Compilers
RESEARCH TRIANGLE INSTITUTE
P.O. BOX 12194
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27709
Sponsored by:
EPA Cooperative Agreement CR819541
EPA Project Officer: Michael Kosusko
AIR AND ENERGY ENGINEERING RESEARCH LABORATORY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
Provided for:
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
WASHINGTON, DC 20460
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POLLUTION PREVENTION CONFERENCE ON
LOW- AND NO-VOC COATING TECHNOLOGIES
Sponsored by:
VS. ENVIRONMENTAL PROTECTION AGENCY
AIR AND ENERGY ENGINEERING RESEARCH LABORATORY
ORGANICS CONTROL BRANCH
RESEARCH TRIANGLE PARK, NC 27711
and
RESEARCH TRIANGLE INSTITUTE
CENTER FOR ENVIRONMENTAL ANALYSIS
POLLUTION PREVENTION PROGRAM
RESEARCH TRIANGLE PARK, NC 27709-2194
and
AMERICAN INSTITUTE FOR POLLUTION PREVENTION
UNIVERSITY OF CINCINNATI
CINCINNATI, OH 45221
11
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TABLE OF CONTENTS
PAGE
INTRODUCTION vi
SESSION 1 OPENING 1
Welcome Address Richard J. Sommerville/San Diego County
Air Pollution Control District 3
Keynote Address Paul J. Eisele/Masco Corporation
A Manufacturing Company's View of Low VOC Coatings 5
Papers Presented:
Coatings Research in the U.S. EPA's Organics Control Branch 13
Using Life Cycle Analytical Techniques to Assess Alternative Coating Systems 25
SESSION 2 TECHNOLOGIES 41
Papers Presented:
Radiation Curing Technology: Ultraviolet (UV)
and Electron Beam (EB) Processing 43
Environmental Compliant Thermoplastic Powder Coating 51
Supercritical Fluid Spray Application of Low-Pollution Coatings
for Plastic Substrates 65
Utilizing Dispersion Resins with Inorganic Solids in a New Formulary Blending
Process to Achieve Synergistic Results of Performance (Expanded Abstract) 77
SESSION 3 POWDER COATINGS : 79
Papers Presented:
Advantages of Powder Coating 81
Aerospace Applications for Powder Coating at Hughes Aircraft Company 89
Fluoropolymer Coatings for Architectural, Automotive
& General Industrial Applications 101
SESSION 4 FEDERAL PROGRAMS 113
Papers Presented:
U.S. Navy Compliance to Shipbuilding and Ship Repair Environmental Regulations 115
Low-VOC Coatings Developed by DOE for
Environmentally Conscious Manufacturers 139
The Precedent-Setting Use of a Pollution Prevention Project in an EPA
Enforcement Settlement: The First Dollar-for-Dollar Penalty Offset 157
Army Pollution Prevention Success Stories 181
SESSION 5 ENCOURAGING POLLUTION PREVENTION 191
Papers Presented:
Pollution Prevention Opportunities in Coatings: Educating Those Who are
Responsible for This Task 193
Economic Incentives to Stimulate the Development and Diffusion of
Low- and No-VOC Coating Technologies 205
Pollution Prevention in the Wood Refinishing Industry 219
The Importance of Product Stewardship and Its Impact
on Pollution Prevention 227
111
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TABLE OF CONTENTS
(Contd)
PAG
SESSION 6 INORGANIC COATINGS 2-
Papers Presented:
Long-Term Corrosion Protection with Single-Coat, High-Ratio Zinc Silicate 2-
Two Surprises from Inorganic Zinc-Rich Silicate Coating
A reactive semiconductor approach to surface protection 24
A New Inorganic Coating for Magnesium Alloys with
Superior Corrosion Resistance 25
Inorganic Chemistry as an Option for Formulating High Solids, Low- and
Zero-VOC Architectural, and Industrial Maintenance Coatings 21
SESSION 7 HIGH SOLIDS AND WATER-BASED COATINGS 28
Papers Presented:
The Development of Practical Zero-VOC Decorative Paints 28
New Environmentally Acceptable Metal Coating Systems 29
Water-Reducible Polyurethane Coatings for Aerospace Applications 31
SESSION 8 APPLICATIONS 1 32
Papers Presented:
Water Based and UV-Cured Coatings for Plastics 32
Water-Borne Lacquers for Aluminum Foil 33
Lower-VOC Coating System Conversion Costs
for the Wood Furniture Industry 34
Development of Ultra-Low VOC Wood Furniture Coatings 35
SESSION 9 AEROSPACE APPLICATIONS 36
Papers Presented:
Replacement of Chromated Epoxy Primers/Wash Primers for
Ground Support Equipment and Space-Related Flight Hardware 36
An Investigation of Flexibility Test Methods for
Low-VOC Aerospace Coatings 37
Waterborne Maskant 35
Low-VOC Organic Coatings for Commercial Aircraft Application 4C
SESSION 10 AUXILIARY SYSTEMS 41
Papers Presented:
Low Volatility Surface Preparation: A Hybrid Approach 41
Transfer Efficiency and VOC Emissions of
Spray Gun and Coating Technologies in Wood Finishing 4;
You Can't Always Judge a Paint Spray Gun Cleaning System by Its Cover 44
IV
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TABLE OF CONTENTS
(Contd)
PAGE
SESSION 11 APPLICATIONS 2 461
Papers Presented:
Priority Manufacturing and Environmental Issues at Military Industrial Facilities 463
Low-VOC Dual-Cure Aerospace Topcoat 467
UV Pollution Prevention Technology in Can Manufacturing 475
Pollution Prevention Opportunities in the Manufacture of Paint and Coatings 489
Appendix A REGISTRANTS A-l
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INTRODUCTION
Surface coating operations release approximately 19 percent of stationary area source
volatile organic compound (VOC) emissions1. Many of these sources cannot be impacted by
add-on controls at a reasonable cost due to their small size and/or the difficulty of capturing
emissions. The reduction of solvent emissions from architectural and other coatings continues
to rely on prevention technologies, such as the replacement of VOC with water or
nonphotochemically reactive solvents, the use of high solids coatings, or improvement of the
efficiency of transfer of the coating to the coated surface. In current practice, reformulation
with nonphotochemically reactive solvents may lead to other environmental problems, such as
increased toxicity, greater stratospheric ozone depletion potential, and worsened multimedia
effects.
A conference tided, "Pollution Prevention Conference on Low- and No-VOC Coating
Technologies," was held on May 25 through 27, 1993 in San Diego, California. The
conference was sponsored by the U.S. Environmental Protection Agency (EPA), Research
Triangle Institute (RTT), and the American Institute for Pollution Prevention (AIPP). The
primary purpose of the conference was to provide a forum for the exchange of technical
information on coating technologies. Specifically, the conference was designed to focus on
improved and emerging technologies that result in fewer VOC and toxic air emissions than
traditional coating systems.
Approximately 230 people attended the conference. Of these attendees, about 50
percent were from industry, 40 percent from government, and 10 percent from consulting
firms and universities. There were nine foreign registrants: three each from Taiwan and the
United Kingdom; and one each from Sri Lanka, Norway, and the Philippines. Conference
registrants are listed in Appendix A.
Technical papers presented at the conference were divided into 11 sessions focusing
on different topical areas including coating technologies, specific coating applications and
case studies, application equipment, and pollution prevention concepts. Several papers
focused on new products and improvements in these areas, such as an electrophoretic urethane
coating from Great Britain, a zero-VOC house paint from Glidden, and developments
involving inorganic polymers such as zinc silicates and silicones. Coatings for substrates,
such as metal (aerospace), wood (furniture), plastic, foil, and concrete, were also discussed.
'U.S. Environmental Protection Agency. 1993. Regional Interim Emission Inventories (1987-1991),
Volumes I and II. EPA-454-R-93-021a and EPA-454-R-93-021b. U.S. Environmental Protection Agency,
Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina. May.
VI
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SESSION 1
OPENING
WELCOME ADDRESS
by
Richard J. Sommerville
Air Pollution Control Officer
San Diego County Air Pollution District
San Diego, California
KEYNOTE
"A Manufacturing Company's View of Low VOC Coatings"
by
Paul Eisele
Director of Health, Safety & Environmental Affairs
Masco Corporation
Taylor, Michigan
PAPERS PRESENTED:
"Coatings Research in the U.S. EPA's Organics Control Branch"
by
Michael Kosusko
U.S. Environmental Protection Agency
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina
'Using Life Cycle Analytical Techniques to Assess Alternative Coating Systems"
by
Keith A. Weitz
John L. Warren (Speaker)
Research Triangle Institute
Center for Economics Research
Research Triangle Park, North Carolina
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WELCOME ADDRESS
by
R. J. Sommerville
As the air pollution control officer for San Diego County, I'm gratified to see an entire
conference devoted to pollution prevention. It's in all of our best interests to eliminate
pollution at the source.
Effective prevention measures can reduce the need for stricter regulations in the future.
We've all heard a lot of talk lately about how the cost of regulations in California are chasing
businesses away. The simple fact is that California is a leader in air pollution regulations—
because it's a leader in producing smog. California is home to 3 of the 10 smoggiest cities in
the country. Environmental regulations are one of the compromises we make in order to
continue living and working in one of the best climates in the world.
But that doesn't mean we can't do things better. At the San Diego Air Pollution Control
District, my staff has literally spent hundreds of hours with business owners and the military
to gather their input on everything from rule development to permit program streamlining.
Fortunately, California has become a pioneer in producing low-volatile organic compound
(VOC) and VOC-free coatings. Also, coating manufacturers are currently marketing products
that exceed regulations in anticipation of stricter rules in the future.
Individual companies are also taking the initiative to reduce or eliminate the use of coatings
that contain VOCs. For example, BASF has developed a new VOC-free, water-based
adhesive bonding primer for the aerospace industry. The company is also developing VOC-
free, air-dried primers which could possibly be used in conventional metal shops. Another
company has begun using powder coatings as a substitute for high-VOC, high-performance
architectural coatings.
Southern California Edison of Irvindale, California has created a Customer Technology
Application Center. The center features a demonstration facility and educates industry about
low-VOC coatings, new spray equipment, and new curing methods including ultraviolet,
radio-frequency, and infrared materials. Its staff works with painters to assist them in
converting to water-based and high-solid coatings.
The center has also made a lot of progress in finding solutions to meet the needs of individual
companies, particularly in the area of water-based wood product coatings. The low-VOC,
water-based coating now produces a more durable finish than standard lacquer. One user
accidentally spilled his coke over a piece of furniture he was working on. The soda was left
on the wood overnight and didn't even make a mark.
3
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Throughout the conference today and tomorrow, you will have the opportunity to leam about
other developments in VOC-free and low-VOC coating technologies and products, as well as
new applications for them. Please keep in mind that your air quality district is there to help
you adapt to these new coating methods. Don't hesitate to use our expertise to help make
your lives easier and your businesses more successful. We're on the same team. Thank you
very much.
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(The woik described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
A MANUFACTURING COMPANY'S VIEW
OF LOW VOC COATINGS
Paul J. Eisele
Director Health, Safety & Environmental Affairs
Masco Corporation
Introduction
Any discussion of low VOC coatings must have a ground work laid to determine the
perspective of the presenter. Masco Corporation and its sister company MascoTech (formerly
Masco Industries) are manufacturers of consumer products and industrial products respectively.
Masco Corporation is the largest manufacturer in the U.S. of furniture and kitchen cabinets, thus
wood products. Masco is also the largest manufacturer of plumbing products, faucets, tubs and
spas. MascoTech is a leading manufacturer of automobile parts and architectural products like
windows and doors. I stress that Masco is a manufacturer concentrating on manufacturing
processes for simple products. Forbes Magazine called Masco "Masters of the Mundane". I
say all this to preface the fact that we focus on making simple products better. Coatings are an
important component of many of our products. Finishing in the Masco "mind" varies from
electroplating of brass, coating metal doors, painting plastic auto parts to finishing wood. Masco
is not a finish supplier but rather a coating user. The Company expects most coating R & D
to be done by its suppliers not in our R & D labs. We do however invest considerable time in
testing application, durability and performance of coatings within the divisions like Delta Faucet
and Drexel Heritage Furniture. The Company does strive to reduce emissions of VOC and air
toxics through a fairly standard mix of pollution prevention, control equipment and coating
application.
Pollution Prevention
The Company has approached pollution prevention as both a cost saver and regulatory
initiative. From a regulatory standpoint the Pollution Prevention Act fit into our existing
programs in media specific regulatory initiatives in the Clean Air Act and CERCLA for example
(Figure 1). In addition the Company was asked by the USEPA to participate in the voluntary
Industrial Toxics Program also known as 33/50. The Program calls for voluntary reductions in
emissions of some seventeen toxic compounds by 33% in 1992 and 50% by 1995. Many of the
target compounds are also VOC's including xylene, toluene, methyl ethyl ketone and methyl
isobutyl ketone which are also common solvents in coatings. Both Masco companies achieved
greater than 33% reductions through 1992 (Figure 2). The greatest reduction in Masco
Corporation was made by the Home Furnishing divisions which include -furniture and fabric
manufacturing (Figure 3). The reductions result from such factors as use of higher transfer
coating application technologies such as high volume low pressure (HVLP) spray guns, limited
use of water borne coatings, and improved manufacturing process resulting in lower rework and
cleaning. The greatest reduction in MascoTech was made by the Architectural Product group
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which include door and window manufacturing (Figure 4). Most of the reductions were
achieved by use of waterborne coatings and glues or powder coating on metal parts, as well as
purchase of precoated steel. The Companies have found greater applicability of waterborne
coatings to metal because the substrate can be made more uniform for water coatings than can
other substrates like wood or plastic.
Low VOC Coatings
Masco generally relies on the marketplace for new coating technologies, that is, we do
not attempt to develop our own coatings. Advances are a result of collaborative efforts between
the Company and finishing suppliers. This is very typical of manufacturers. In some instances
the product may dictate extensive R & D to use lower VOC coatings. One such example is
automotive headlight manufacturing done by MascoTech Coatings. Industry demands for light
weight vehicles without sacrificing safety have led to utilization of composite materials in autos.
The coating demands are great since in some instances they play an important role in the
function. MascoTech uses silicon to coat poly carbonate lenses as well as UV inhibitor to
prevent cracking to give the plastic the properties of glass. The plastic light housing is vacuum
metalized and then conventionally topcoated to give the reflective properties. The resulting head
or tail lamp assembly is much lighter than the old assembly made of glass and metal with no loss
of quality. Vacuum application is very efficient, as low to no VOC materials can be used.
MascoTech coating is now experimenting with a high solids base and top coat applied in the
vacuum chambers. There have been numerous problems in the fouling of the vacuum chambers
to date but when perfected this will drastically reduce VOC emissions.
The use of low VOC materials for wood coating has also been challenging. Lexington
Furniture, a Masco Corporation company began attempting to use waterborne coatings in the late
1980's in production. To date its success has been on particular wood species, and finishes
which do not require smooth, rich finishes, for example wicker, rattan and one oak suite. Since
that time more lower VOC coatings are being used in production but still limited to particular
woods and particular fashion looks. Wood is a difficult substrate because of its porosity, non
uniformity of substrate, swelling when moist, and inability to apply high temperature drying.
Henredon Furniture has had some success with a couple of suites. Universal Furniture is testing
a reverse hybrid system, that is where waterborne stains or color coats are used followed by
coating with traditional nitrocellulose lacquers sealer and topcoats. This means changes to
conventional finishing in that extensive wiping and sanding must be done making it more labor
intensive manufacturing. It does have the advantage of achieving VOC reductions without the
disadvantage of difficult repair or rework. Most waterborne coating approaches had utilized
conventional stains on wood followed by waterborne sealers and topcoats. A major problem has
been rework or repair because waterborne topcoats are not as amenable as conventional
nitrocellulose which is very forgiving and easy to remove or rework with VOC solvents. This
is especially frustrating for a wood furniture piece with extensive value added prior to finishing.
Summary
Masco like many other manufacturers has found it easier to utilize low VOC coatings on
metal products rather than plastic or wood. Both plastic and wood are not uniform substrates
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for finishing materials and are susceptible to damage with high temperature drying or setting.
The Companies, both Masco Corporation and MascoTech, have had far greater success to date
in reducing VOC's by a combination of better solvent management, improved application
technologies and some use of conventional controls rather than by low VOC coatings for non
metal materials. With more research on finishing material chemistry and application, low VOC
coatings will become a bigger share or "piece" of the VOC reduction "pie". Activities like this
workshop are necessary to insure that recent advances are known and understood so that they
can be assimilated into the mainstream of manufacturing. Some of us wish that low VOC
coatings were available and usable for all of products now. The Company and its suppliers are
committed however to continuous improvement in its products and manufacturing processes to
utilize the complete mix of technologies to reduce VOC and toxic emissions, which in the future
will be achieved through greater reliance on low VOC coatings.
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FIGURE 1
CERCLA
INDUSTRIAL
TOXICS
00
RCRA
Pollution
Prevention
CWA
STORM WATER
NPDES
SARA
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MUURE 2
MASCO TOXICS PROGRAM
CO
CO
CO
CD
D)
c8
O
CO
Q
CO
T3
C
D
O
CL
5000
4000
3000
2000
1000 -
0 -
1988
Masco Corporation
• • • • • MascoTech, Inc.
1989
1990
1991
1992
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FIGURE 3
MASCO CORPORATION
TOXICS REDUCTION PROGRAM
CO
T3
C
cd
CO
13
O
3000
b,
Q)
D)
(5
O
CO
b
CO
C
Z3
O
CL
2000 -
1000
Home Furnishings
• • • • • Building Products - Wood
*• ••• • Building Products - Plumbing
1988 1989 1990 1991 1992
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MASCOTECH, INC.
TOXICS REDUCTION PROGRAM
CO
T3
03
CO
ID
0)
E>
03
O
CO
Q
CO
13
O
0.
1500
1000
500
0
Architectural Products
Transportation
Miscellaneous
1988
1989
1990
1991
1992
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12
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COATINGS RESEARCH IN THE U.S. ERA'S
ORGANICS CONTROL BRANCH
Michael Kosusko
U.S. Environmental Protection Agency
Air and Energy Engineering Research Laboratory
Organics Control Branch
Research Triangle Park, North Carolina
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ABSTRACT
This paper provides a brief overview of research and development
projects in the Organics Control Branch of the U.S. Environmental
Protection Agency's Air and Energy Engineering Research Laboratory
that impact on surface coating processes. Projects can be
characterized as: (1) scoping studies, in which an industry or process
is characterized and pollution prevention (P2) opportunities are
identified; (2) technology assessment and development projects, in
which the feasibility of specific coating technologies or P2
techniques is evaluated; (3) demonstration projects, in which methods
of reducing emissions are tested in cooperation with industrial
partners; or (4) technology transfer projects, such as this
conference. Scoping projects are ongoing for paper and other webs
(surface coating) , furniture restoration and repair, printing,
architectural and industrial maintenance coatings, consumer/commercial
adhesives, and roofing. Technology assessment and development
projects are ongoing to evaluate very low-VOC, non-waterborne coatings
and a 2-component epoxy topcoat for wood furniture manufacturing, to
identify technical barriers to the use of radiation-cured and
waterborne coatings, and to assess innovative ink-feed systems for
printing. Demonstration projects are planned for auto body
refinishing, for coated and laminated substrate manufacturing (i.e.,
the use of aqueous adhesives and of alternative equipment cleaning
methods), and for the design of recirculating spray booths
incorporating VOC concentration gradient phenomena.
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(This paper has been reviewed in accordance with the U.S.
Environmental Protection Agency's peer and administrative review
policies and approved for presentation and publication.)
INTRODUCTION
•For more than two decades, the U.S. Environmental Protection
Agency's (EPA) Air and Energy Engineering Research Laboratory (AEERL),
located in Research Triangle Park, North Carolina, has been exploring
control approaches for the pollutants and sources that contribute to
air quality problems. AEERL has successfully developed and
demonstrated cost-effective sulfur dioxide, nitrogen oxides, and
particulate control technologies for fossil fuel combustion sources.
More recently, it has expanded its interest to areas that include
indoor air quality, radon, organic control, stratospheric ozone
depletion, and global warming. The AEERL also develops inventories of
many types of air emissions. Over the past several years, AEERL has
made a substantial effort to expand pollution prevention as the
preferred choice to reduce air emissions. Its goal is to conduct
research that will result in the greatest possible reduction of air
pollution for the lowest cost.'1
The Organics Control Branch (OCB) of AEERL is charged with
developing and assessing pollution prevention (P2) techniques and add-
on control technologies for reducing organic air emissions; i.e.,
organic air toxics (hazardous air pollutants [HAPs]) and volatile
organic compounds (VOCs). OCB's P2 research is focused in three
technical areas: (1) Surface Coating, such as wood furniture
finishing, printing, and the use of adhesives and radiation-cured
coatings; (2) Solvent Cleaning, such as vapor degreasing, process
equipment cleaning, and in-process precision cleaning; and (3)
Consumer/Commercial Products (C/CP), including traditional consumer
products (e.g., hair spray and household cleaners) and non-process
solvent use in commercial operations such as textile manufacturing,
roofing, and furniture refinishing. Each of the industries with which
OCB is working has concerns about emissions from each of OCB's
technical areas. Most of these industries use surface coatings, use
solvents (to prepare surfaces for coating or to clean equipment), and
use a wide variety of prepackaged commercial products in their
facilities. This paper will discuss OCB's projects that impact
surface coating operations. Projects and project contacts are
provided Appendix I.
Generally, projects in the Organics Control Branch can be divided
into four categories:
(1) Scoping Studies characterize an industry or process and its
emissions and identify P2 opportunities to reduce those
emissions. Scoping projects are ongoing for furniture
restoration and repair, paper and other webs coating, printing,
roofing, architectural and industrial maintenance (AIM) coatings,
and consumer/commercial adhesives.
(2) Technology Assessment and Development Projects evaluate the
technical and economic feasibility of specific coating
technologies or P2 techniques. Technology assessment and
development projects are ongoing to evaluate very low-VOC, non-
waterborne coatings and a two-component epoxy topcoat for wood
15
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furniture manufacturing, to identify technical barriers to the
use of radiation-cured and waterborne coatings, and to assess
innovative ink-feed systems for printing.
(3) Demonstration Projects investigate methods of reducing emissions
in cooperation with industrial partners. Demonstration projects
are in the works for coated and laminated substrate
manufacturing, for the design of recirculating spray booths
incorporating VOC concentration gradient phenomena, and for auto
body refinishing.
(4) Technology Transfer Projects: Such as this conference, The
Pollution Prevention Conference on Low- and No-VOC Coating
Technologies, or the development of information manuals or
software evaluating prevention alternatives.
SCOPING STUDIES
Consumer/Commercial Products (C/CP) Report to Congress (RTC) Support
Information on non-process solvent use was evaluated for 15
industrial and commercial source categories to characterize VOC
emissions and identify P2 opportunities. Non-process solvents are^
used by industry, commercial operations, and/or individual consumers;
they are not incorporated into a product or chemically modified as
part of the manufacturing process. Project results will support a
Report to Congress, required by §183 (e) of the Clean Air Act
Amendments of 1990 (CAAA), which addresses emissions of VOCs from
consumer or commercial products. Successful P2 approaches will
support regulatory efforts resulting from the Report to Congress.
As a result of this evaluation, five categories were selected for
further study. These categories are:
1) Textile Manufacturing
2) Furniture Repair and Refinishing
3) Roofing
4) Hold Release Agents, and
5) Heating, Ventilation and Air-Conditioning (HVAC) Coil and
Parts Cleaning.
For each category, a more detailed evaluation of emissions, emission
sources, and P2 opportunities is being completed. Three of these
categories—Furniture Repair and Refinishing; Roofing; and Textile
Manufacturing (e.g., screen printing)—use surface coatings. Reports
detailing emissions and P2 opportunities for the five categories are
expected during Fall 1993.
Assessment of Pollution Prevention (P2) Opportunities in Five
Industries
In this small cooperative project with the South Coast Air
Quality Management District (SCAQMD), emissions and P2 opportunities
have been assessed for five industries, all of which use surface
coatings: (1) Architectural and Industrial Maintenance (AIM) Coatings;
(2) Consumer/Commercial Adhesives; (3) Rotogravure Printing; (4)
Flexographic Printing; and (5) Graphic Arts. The final report for
this project is expected during Fall 1993.
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Source Reduction Review Program (SRRP) Focus Groups
The objective of the Source Reduction Review Program (SRRP) is to
ensure the consideration of P2 options during the development of air
toxic (also known as Maximum Achievable Control Technology [MACT])
regulations for 17 of the many source categories to be regulated under
Title III of the CAAA by the year 2000. The purpose of this project
is to identify P2 opportunities via focus group input for five of
these categories. Of the five, only one is a surface coating category
(i.e., Paper and Other Webs). The other categories are: (1)
Reinforced Plastics (Boat Building); (2) Integrated Iron and Steel
Manufacturing; (3) Plywood/Particle Board Manufacturing; and (4)
Acrylic/Modacrylic Fiber Production. Focus groups will include the
participation of industrial, governmental, and academic experts in
order to get as broad a perspective as possible. The Paper and Other
Webs focus group is scheduled to meet before September 30, 1993, as
are the Reinforced Plastics and Iron and Steel focus groups.
TECHNOLOGY ASSESSMENT AND DEVELOPMENT PROJECTS
Wood Furniture Finishing
Status and Future Developments in Very Lov-VOC Coatings. The
objective of this project is to establish the status of research and
development (R&D) and market development for very low-VOC coatings
used for wood furniture finishing. Information will be gathered
through contacts with resin suppliers, paint manufacturers, wood
furniture manufacturers, and their trade associations. The question,
•What is really available in terms of low-VOC coatings?" will be
addressed as will the status of ongoing development projects. The
technical barriers and concerns of industry about these coatings will
be identified and addressed. Opportunities for demonstrating very
low-VOC coatings for wood furniture finishing will be identified. The
final report for this project should become available during the Fall
of 1993.
Waterborne Two-Component Epoxy Topcoats. Details of this project
will be presented on Wednesday afternoon. May 26, 1993, at this
conference. The paper will be available in the conference proceedings
(pages 357-365) . This project is cooperatively funded with SCAQMD. A
two-component water-based epoxy resin coating system containing less
than 0.08 Ib/gal (10 g/1) VOC has been developed as both clear and
white-pigmented topcoats. These topcoats have met most performance
criteria including: (1) a VOC content of less than 0.08 Ib/gal; (2)
high gloss; (3) dry to touch in 10 minutes or less, dry to handle in
15 minutes or less; and (4) a 2H pencil hardness.
Technical Barriers to the Use of Radiation-Cured and Waterborne
Coatings
This project is part of SRRP and is just underway. The use of
radiation-cured (e.g., ultraviolet [UV]-cured and electron beam [EB]-
cured) or water borne coatings is a P2 option for several SRRP source
categories. However, technical barriers to their broadened usage such
as concerns about toxicity and the difficulty of coating complex parts
using radiation-cured coatings exist. The objective of this project
is to identify and characterize these technical barriers and to
identify and complete critical research to overcome them.
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Innovative Ink Feed Systems
This project is also part of SRRP and is just underway. The
systems (e.g., piping, tanks, and mixers) used to feed ink to printing
presses and their subsequent cleaning requirements are the source of
substantial volatile organic HAP emissions. Substitute infc feed
systems could substantially reduce these emissions.
DEMONSTRATION PROJECTS
Auto Body Refiniehing
This project is being completed cooperatively with SCAQMD. Its
objective is to demonstrate a P2 technique or techniques to reduce
volatile organic emissions from auto body refinishing operations.
Although project details have not yet been finalized, we will probably
work with a university-based paint research center to field- or pilot-
test innovative, low- or no-VOC coatings that have been proven at the
bench-scale. Work is expected to be underway during 1993.
Retrofit of Existing Solvent-based Flexible Substrate Coating
Equipment to Use Water-based Coating Systems
The coated and laminated substrate manufacturing industry makes a
wide variety of pressure sensitive products such as masking, cloth
(duct), and cellophane tapes, tags, labels, and a number of exotic
laminated products. It was selected for study because of significant
air emissions of methyl ethyl ketone (MEK) and toluene reported in the
1990 Toxics Release Inventory System (TRIS)2; i.e., it is the #1 source
for MEK (8,050 tons[7,300 Mg]) and the #3 source for toluene (13,000
tons[11,800 Mg]). A focus group, including members of the Pressure
Sensitive Tape Council (PSTC) and the Tag and Label Manufacturers
Institute (TLMI), and academic and state environmental experts, helped
OCB identify opportunities for significant reductions of organic HAP
emissions in this industry.
The use of solvent-borne coatings (e.g., adhesives) was
identified as the primary source of the industry's toluene and MEK
emissions. The key barriers to the use of waterborne coatings by
small firms in this industry are: (1) The capital cost of purchasing
new equipment which could use waterborne adhesives and (2) The lack of
readily available technical information which would allow the
retrofitting of existing solvent-based equipment to use waterborne
coatings. PSTC representatives from large companies indicated that
they would work with OCB to document successful applications of
retrofit technology so that a descriptive "how to" manual could be
developed for use by small businesses in the industry. Once the use
of waterborne coatings is implemented by small businesses, significant
toluene and MEK emission reductions would be achieved.
A report documenting background issues for retrofitting equipment
to use waterborne coatings should become available during the Fall of
1993. The high level of industry participation through the PSTC will
allow demonstration and documentation efforts to be initiated during
1993.
Partitioned, Recirculating Spray Booth
Recirculation in paint spray booths has been recognized for many
18
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years as a means of increasing the concentration and reducing the
volume of spray booth exhaust. This allows the use of a smaller add-
on control device, hence reducing air pollution control costs. A
partitioned, recirculating paint spray booth is shown in Figure 1.
Partitioning of the spray booth exhaust stream takes advantage of the
VOC concentration gradient that exists vertically across the booth
exit. VOCs stratify in the booth, and their concentration is greatest
closer to the floor. By pulling the booth exhaust stream from the
bottom portion of the booth and the recirculating stream from the top
portion of the booth, the concentration of the exhaust stream can be
enhanced, perhaps reducing the exhaust volume to be controlled below
that of a simple recirculating booth. Preliminary field tests have
shown the feasibility of reducing controlled air volumes by 50-75%
below those of non-recirculating booths.
A demonstration of the stratified recirculation concept is
planned at the U.S. Marine Corps (USMC) Maintenance Depot near
Barstow, California. The demonstration will be completed
cooperatively with the Marine Corps and Penn State University. During
the demonstration, an existing spray booth will be modified to use
both recirculation and partitioning. A movable plenum will be used to
evaluate the optimum height for flow partitioning. An additional
control technology will be evaluated during the demonstration. Spray
booth exhaust will feed to an add-on control device supplied by Terr-
Aqua which uses UV light to destroy organics absorbed on a catalytic
substrate, scrubbing with ozonated water, and a final activated carbon
polishing step.
Paint Application Technology
Evaluation of Ultra Low Volume (ULV) Spray Gun System. The
objective of this project is to evaluate an ULV spray gun system.
Tests have been completed cooperatively with the U.S. Air Force at
Warner-Robins Air Force Base, Georgia. Qualitative results of the
test are promising. A large improvement of paint utilization
efficiency was attributed to the enhanced paint lay down or flow out
provided by the gun. This and the ability to spray high viscosity
paints (which contain fewer solvents) have led to a 50 to 75%
reduction in VOC emissions. The final project report is expected
during Fall 1993.
19
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FRESH MAKEUP
AIR INTAKE
BOOTH INTAKE
DUCT
RECIRCULATION
DUCT
SPLIT Fl
DUC
TO EXHAUST
1. The Partitioned, Recirculating Spray Booth Concept
20
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Spray Qun Cleaning. The purpose of this project is to compare
emissions from two types of paint spray gun cleaning equipment (i.e.,
open and closed systems) to each other and to those from current
cleaning practices. In the open system, cleaning solvent is sprayed
from the gun, with its spray tip removed, into an open container that
is shaped to minimize solvent bounce-back and that has air flow into
the bottom of the container. The closed system consists of spraying
cleaning solvent through the gun while it is enclosed in a capture
device. This project, which should be completed during Fall 1993, is
being done in support of EPA's Control Technology Center (CTC). The
CTC provides technical support to local, state, and EPA Regional
environmental personnel, small businesses, and international clients.
It is co-sponsored by AEERL and EPA's Office of Air Quality Planning
and Standards.
TECHNOLOGY TRANSFER
Technology transfer (T2) is the final and, perhaps, the most
important type of project activity in the Organics Control Branch.
Through T2, the results of OCB's research are provided to the people
who can use it, hopefully in a format that they can easily use. T2
also provides OCB an opportunity to interact with its potential
clients (i.e., through workshops and conferences) to better understand
their needs and the status of technology in many industries. The most
straightforward means of providing information to potential users are
project reports and presentations at large professional conferences.
However, these mechanisms are not necessarily targeted at the user
community. Some of the difficulty of reaching the right audience can
be overcome by providing report copies to local, state, and regional
P2 and small business assistance providers, the Control Technology
Center, and industry trade associations. Information can also be
distributed through P2 data bases and electronic bulletin boards such
as the Pollution Prevention Information Clearinghouse (PPIC) which, as
part of the Pollution Prevention Information Exchange System (PPIES),
is managed by EPA's Office of Environmental Engineering and Technology
Demonstration.
EPA-sponsored workshops and conferences provide an opportunity
for interacting directly with a targeted audience. OCB has completed
two conferences for surface coatings. The Surface-Coating-Free
Materials Workshop was held in July 1991, to explore the potential for
development and use of materials that would not need to be coated
during manufacture or recoated during use. If such materials were to
come into widespread use, VOC and air toxic emissions associated with
surface preparation (cleaning), coating, and paint stripping before
recoating could be avoided. A summary of this workshop is available
from the National Technical Information Service (NTIS)3. This is the
second conference. The Pollution Prevention Conference on Low- and
No-VOC Coating Technologies is being held to provide a forum for
exchanging technical information on innovative coating technology and
to allow EPA to interact with industry, academia, and others
interested in surface coating technology.
A third coatings conference has been proposed for March 1995,
with much the same objective as this conference. It would probably be
held on the East Coast, in the Raleigh-Durham, North Carolina, area.
A series of technology transfer workshops may also be proposed for
completion during 1994 to allow OCB personnel to present the results
of their research to, and to interact with, the user community.
21
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SUMMARY AHP CONCLUSIONS
The Organics Control Branch has a broad program in pollution
prevention which impacts many industries ranging from wood furniture
manufacturing to coated and laminated substrate manufacturing to
printing ajid publishing. Each of these industries has common
concerns. They all use surface coatings; most use solvents for
preparing surfaces for coating or for cleaning equipment; and all use
an abundance of prepackaged commercial products. This paper
summarizes surface coating activities in OCB. Although many of its
initial research products are nearing completion, OCB expects that its
surface coatings program will continue to grow and develop. The input
of a broad spectrum of industry, academic, and other surface coating
experts, such as the attendees at this conference, is needed to
continue to enhance the focus, quality, and content of OCB's current
and future research activities.
REFERENCES
1. Shaver, E.M., "Pollution Prevention for Cleaner Air: EPA's Air and
Energy Engineering Research Laboratory, • Pollution Prevention
Review, Winter 1992-93, pp.41-50.
2. Toxic Chemical Release Inventory, National Library of Medicine
Toxnet System, U.S. Environmental Protection Agency, 1990.
3. Northeim, C.M., M.W. Moore, and J.L. Warren, Surface-Coating-Free
Materials Workshop - Summary Report, EPA-600/R-92-159 (NTIS PB93-
101160), August 1992.
22
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APPENDIX I; SUMMARY OP OCB PROJECTS AND PROJECT CONTACTS
I. SCOPING
A. Consumer/Commercial Products Report to Congress
1. Furniture Repair & Refinishing
2. Roofing
3. Textile Manufacturing
B. Assessment of P2 Opportunities in Five Industries
C. Source Reduction Review Program (SRRP) Focus Groups
n. TECHNOLOGY ASSESSMENT AND DEVELOPMENT
A. Wood Furniture Finishing
1. Status and Future Developments in Very Low-VOC Coatings
2. Waterbome Two-component Epoxy Topcoats
B. Technical Barriers to the Use of Radiation-cured and Waterbome Coatings
C. Innovative Ink-feed Systems
III. DEMONSTRATIONS
A. Auto Body Refinishing
B. Retrofit of Existing Solvent-based Flexible Substrate Coating Equipment
to Use Water-based Coating Systems
C. Partitioned, Recirculating Spray Booth
D. Paint Application Technology
1. Evaluation of Ultra Low Volume (ULV) Spray Gun System
2. Spray Gun Cleaning
W. TECHNOLOGY TRANSFER
A. Surface-coating-free Materials Workshop
B. P2 Conference on Low- and No-VOC Coating Technologies - San Diego
C. P2 Conference on Low- and No-VOC Coating Technologies - East Coast
R. McCrillis
J.Whitfield
M.Kosusko
M.Kosusko
C-Nunez
RMcCrillis
C.Nunez
CJMunez
G. Ramsey
C.Vogel
CDarvin
C.Darvin
M.Kosusko
M.Kosusko
M.Kosusko
TELEPHONE NUMBERS
Chuck Damn
Mike Kosusko
Bob McCrillis
Carlos Nunez
Geddes Ramsey
Chet Vogel
Jamie Whitfield
Control Technology Center HOTLINE
919/541-7633
919/541-2734
919/541-2733
919/541-1156
919/541-7963
919/541-2827
919/541-2509
919/541-0800
23
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24
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
USING LIFE CYCLE ANALYTICAL TECHNIQUES TO ASSESS
ALTERNATIVE COATING SYSTEMS
Keith A. Weitz
John L. Warren
Environmental Management Systems
Center for Economics Research
Research Triangle Institute
Research Triangle Park, NC 27709
INTRODUCTION
Life cycle assessment (LCA) is a holistic approach to assessing the environmental and
human health burdens associated with a given product system. It seeks to reconcile
technology and ecology at each stage of the life cycle of products, processes, and activities
from acquiring raw materials to recycling or disposal by identifying system inputs and
outputs; assessing the potential impacts of those inputs and outputs on the natural
environment, human health, and natural resources; and implementing opportunities for
achieving improvements. Life cycle thinking starts before the cradle (R&D, design) and goes
beyond the grave (recycling, re-use).1
This paper describes the LCA process, which can be used to assess alternative low-
and no-volatile organic compound (VOC) coating systems with the objective of minimizing
potential impacts to the environment and human health. In this context, LCA is useful for
recognizing trade-offs between alternative coating systems that may not have eliminated
environmental and human health impacts but merely transferred them to other life cycle
stages.
Currently, no protocol exists for conducting an LCA. However, LCA generally
consists of the following components:
Goal Definition and Scoping: Identifies the purpose and objectives of the LCA, as
well as study boundaries, data needs, comprehensiveness, users of the results, and
potential applications.
25
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Inventory Analysis: Identifies and quantifies—to the extent possible—resource and
energy inputs, air emissions, waterborne effluents, solid waste, and other inputs and
outputs associated with a product system. This information is compiled into a life
cycle inventory.
Impact Assessment: Identifies, characterizes, and values potential impacts of concern
to the natural environment, human health, and natural resources associated with the
inputs and outputs of a product system.
Improvement Assessment: Identifies, evaluates, and implements opportunities for
environmental and human health improvements. Opportunities for improvements may
be realized at any stage of the LCA process.
LCA is not necessarily a linear or stepwise process. Rather, as suggested by Figure 1,
information from any component can complement information from the other components.
For instance, opportunities for environmental improvements do not necessarily stem from the
life cycle improvement assessment but can be realized at any stage of the LCA process. The
inventory component alone may be used to identify opportunities for reducing inputs from
or outputs to the environment.
Improvement
Assessment
Goa/
Definition
and Scoping
Impact * •—• ' Inventory
Assessment Analysis
Figure 1. LCA Framework
APPLYING LCA TO EVALUATE LOW- AND NO-VOC COATING SYSTEMS
Government legislation, such as the 1977 and 1990 Gean Air Act Amendments, is
the major force behind the conversion from conventional to low- and no-VOC coating
systems. Another motivation for this conversion is to reduce or eliminate environmental and
human health concerns associated with VOCs, such as photochemical smog and human
respiratory damage.
However, switching from conventional to alternative coating systems may be
exchanging one problem for another. For example, an alternative coating system may replace
VOCs with other hazardous materials, or the alternative coating system may require special
26
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drying and curing equipment that significantly increases energy usage. When switching to
alternative coating systems, trade-offs besides reducing VOCs need to be evaluated. LCA
may be an effective approach for assessing such trade-offs. We elaborate on the LCA
process summarized in the introduction of this paper by comparing a conventional coating
system with a no-VOC powder coating system. The characteristics of the two systems are
as follows:
• Conventional coating system: 30 percent solids, 70 percent solvents
• No-VOC powder coating system: 100 percent solids, 0 percent solvents
Table 1 provides a comparison of the basic components of conventional and no-VOC powder
coating systems.
Goal Definition and Scoping
Goal definition and scoping forms the basis of interrelationships between the
inventory, impact, and improvement assessment components. As suggested in Figure 1, goal
definition and scoping are both discrete activities and the basis of the life cycle inventory,
impact, and improvement assessment components.
The goal definition activity clearly identifies and defines the purpose and objectives
of the LCA at the beginning, as well as maintains consistency with the goals and objectives
of the study throughout the LCA process. An example of goal definition, which will also be
used as the guiding goal for purposes of this paper, is to assess alternative coating systems
to choose the coating system that generates minimal environmental and/or human health
impacts.
The breadth and depth of the LCA, or scope, is governed by the defined study
boundaries, comprehensiveness, data needs, impact areas included and excluded,
methodologies employed, users of results, and potential applications of the LCA (e.g., LCA
as a baseline vs. comparative study). The scope of the LCA will undoubtedly be bounded
by resource (i.e., money, time, technical expertise) constraints that limit the practitioner from
gathering and analyzing data for each and every possible component of a system's life cycle.
Thus the primary goal of scoping in this case may be to match the level of detail of the LCA
with available resources while allowing the practitioner to achieve the goal of the LCA.
Because scoping may be both a discrete and integral component in LCA, it may occur
at the beginning of the LCA and may be reevaluated when beginning or during the inventory
analysis and the impact and improvement assessment components. For example, data
required to conduct an impact assessment may be missing from the inventory component or
may be of insufficient quality. In this case, the scope of the impact assessment, and thus the
overall LCA, may have to be constricted.
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TABLE 1. COMPARISON OF BASIC COMPONENTS OF CONVENTIONAL
VERSUS POWDER COATING SYSTEMS23
Component
Conventional Coating
Powder Coating
Basic coating inputs:
Pigment
Binder (resins)
Carrier (solvents)
Materials pretreatment
Application equipment
Drying
Utilization rate
Output waste
Air pollution
Water effluent
Solid waste
Hazardous waste
Overhead costs
Finish quality
10-20%
10-20%
60-80%
Solvent-based primer tank(s), air
dried
Spray booth
400" oven, 40-45 minutes
60-70%
VOCs
Waste water from equipment
cleaning
More packaging materials needed to
protect finish
Liquid overspray
Paint sludge
More labor
More equipment to meet
VOC regulations
More energy costs
40-60%
40-60%
0%
Anodic electrocoat tank,
oven dried (475°, 5
minutes)
Spray booth
400° oven, 10-15
minutes
95-98%
No VOCs
Waste water from
equipment cleaning
Less packaging materials
needed because finish is
more durable
Powder overspray can
be easily
recycled/reused.
Higher gloss
Higher coatage
Higher durability
Higher corrosion
resistance
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Inventory Analysis
Life cycle inventory analysis is a technical, data-based process of quantifying energy and
raw material requirements, atmospheric emissions, waterborne effluents, solid wastes, and
other inputs or outputs throughout the entire life cycle of a system. Life cycle stages include
raw materials acquisition, manufacturing, use/reuse/maintenance, and recycle/waste
management. Figure 2 illustrates a simplified representation of the full product life cycle.
Input*
SyMm Boundary
Raw
Materials
Energy
Materials manufacture
Product fabrication
HtoMrtMckagincyaiatribution
Output*
Atmospheric
Emissions
Waterborne
Wastes
Solid
Wastes
Coproducts
Other
Releases
Syctwn Boundaiy
Figure 2. Simplified Full Product Life Cycle4
Life cycle inventory analysis is a static representation of a dynamic system, as is the
entire LCA process. That is, the life cycle inventory is a "snapshot" of inputs and outputs
of a given product system. In light of this limitation, some general applications of the life
cycle inventory are the following:
• Establish a baseline of information on a system's overall resource and energy
consumption and environmental loadings;
• Identify stages within the life cycle of a product or process where inputs and
outputs might be reduced;
• Compare the system's inputs and outputs associated with alternative products,
processes, or activities;
• Help guide the development of new products, processes, or activities toward a
net reduction of resource and energy requirements and environmental
emissions; and
• Help identify areas to be addressed during life cycle impact assessment.4
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Because its methodology has been evolving over a 20-year period, life cycle
inventory analysis is relatively well developed. We describe the steps involved in
conducting the inventory analysis using the two coating systems—A (conventional) and B
(powder coating)—as an example. EPA developed these eight steps for conducting an
inventory analysis.4
1.) Define the Purpose and Scope of the Life Cycle Inventory Analysis. The
purpose of the life cycle inventory analysis when evaluating two coating systems may be
to provide baseline information for comparing the environmental and human health
impacts of system A (conventional) versus system B (powder coating). The scope of the
inventory analysis should, at a minimum, clearly define the following study components:
• product, process, or activity to be studied;
• reasons for conducting the inventory analysis, including the needs of and
potential applications for pertinent user groups;
• use of the results of the inventory analysis by the practitioner;
• elements of the inventory analysis, such as energy and raw material inputs and
waste or coproduct outputs; and
• elements not addressed hi the inventory analysis, such as socioeconomic and
aesthetic issues, for example.4
2.) Define the System Boundaries. Once the goals and objectives for preparing
the life cycle inventory have been determined and the intended scope identified, the
practitioner can define the system boundaries. Whereas determining the scope of the
inventory analysis defines both the issues and physical system to be addressed,
determining the system boundaries defines the portions of the physical system that will be
included in the inventory analysis. A complete life cycle inventory analysis will establish
boundaries that represent the system broadly, over the entire life cycle as shown in Figure
2.
Some helpful questions for setting and describing specific system boundaries might
include the following:
• Does the system need to cover the entire life cycle?
• What will the product be used for, or is the study intended to compare
systems?
• What ancillary materials or chemicals are used to make or package this
product or run the processes?
• In a comparative analysis, are any extra products required to allow one product
to deliver equivalent or similar performance to another?
Figure 3 shows an example of the basic system boundaries for the two coating systems.
30
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3.) Devise an Inventory Checklist After defining the purpose, scope, and
boundaries of the inventory analysis, the practitioner can prepare a checklist to guide data
collection and to develop an inventory model. The practitioner should address eight
general decision areas on the generic checklist shown in Table 2. This checklist is not
definitive; the practitioner may want to tailor the checklist to meet specific needs.
4.) Institute a Peer Review Process. Because LCA is a fairly new concept and
its methodology is not widely accepted and well-understood, LCA reviewers have
recommended using a peer review process. In the context of LCA, peer review is not just
a post-study activity but an integral component that is implemented early in the LCA
process. In the context of inventory analysis, a peer review process may help to validate
the following components:
• scope and boundary definitions;
• data collection and compilation plan;
• key assumptions and value judgments, if any;
• validity of results; and
• interpretation and communication of results.
Checklists such as the one presented in Table 2 are useful for organizing information on
these components to aid in the peer review process.
5.) Gather Data. Data gathered in the inventory analysis may come from a
number of different sources and may be categorized in different ways. Some example
data categories include the following:
• Individual Process- and Facility-Specific: data gathered from a particular
operation within a given facility
• Composite: data from the same operation or activity combined across
locations
• Aggregated: data combining more than one process operation
• Industry-Average: data derived from a representative sample of locations and
believed to statistically describe the typical operation across technologies
• Generic: data whose representativeness may be unknown but that are
qualitatively descriptive of a process or technology
31
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> 3)
£ *
Sf
n
1
t
*.
i
1
?
I
1
|
\
z
c
^1
^
c
a
EC
It
• ^
!i
RtcycWWi
M*n*g«irM
^5
Figure 3. Basic Life Cycle System Boundaries for Coating Systems
32
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TABLE 2. A TYPICAL CHECKLIST OF CRITERIA WITH WORKSHEET FOR
PERFORMING A LIFE-CYCLE INVENTORY4
LIFE-CYCLE INVENTORY CHECKLIST
INVENTORY OF:
Purpose of Inventory: (check all that apply)
Private Sector Use Public Sector Use
Internal Evaluation and Decision Making Evaluation and Policy Making
Q Comparison of Materials, Products, or Activities D Support Information for Policy and Regulatory Evaluation
D Resource Use and Release Comparison with Other D Information Gap Identification
Manufacturer's Data D Help Evaluate Statements of Reductions In Resource Use
D Personal Training for Product and Process Design and Releases
O Baseline Information for Full LCA Public Education
External Evaluation and Decision Making D Develop Support Materials for Public Education
Q Provide Information on Resource Use and Releases D Assist in Curriculum Design
D Substantiate Statements of Reductions in Resource
Use and Releases
Systems Analyzed
List the product/process systems analyzed in this inventory: ^___^_^____^____^^^_^^__^__^___^_^^_^__
Key Assumptions: (Hst and describe)
Define the Boundaries
For each system analyzed, define the boundaries by life-cycle stage, geographic scope, primary processes, and ancillary inputs included in
the system boundaries.
Postconsumer Solid Waste Management Options: Mark and describe the options analyzed for each system.
D Landfill O Open-loop Recyc*ng_
D Combustion D Closed-loop Recycling
Composting D Other '
Befit for Comparison
D This is not a comparative study. D This Is a comparative study.
State basis for comparison between systems: (Example: 1,000 units, 1,000 uses)
If products or processes are not normally used on a one-to-one basis, state how equivalent function was established.
Computational Model Construction
D System calculations are made using computer spreadsheets that relate each system component to me total system.
Q System calculations are made using another technique. Describe:
Describe how inputs to and outputs from postconsumer solid waste management are handled.
Quality Assurance: (state specific activities and initials of reviewer)
Review performed on:
D Data Gathering Techniques Q Input Data
D Coproduct Allocation D Model Calculations and Formulas_
O Results and Reporting ~
Peer Review: (state specific activities and initials of reviewer)
Review performed on:
D Scope and Boundary D Input Date
D Data Gathering Techniques D Model Calculations and Formulas
D Coproduct Allocation O Results and Reporting
Results Presentation D Report may need more detail for additional use beyond
D Methodology Is fully described. defined purpose.
D Individual pollutants are reported. a Sensitivity analyses are included in the report
D Emissions are reported as aggregated totals only. Ust,
Explain why: D Sensitivity analyses have been performed but are not included
in the report. Ust
in the report. List:
D Report is sufficiently detailed for its defined purpose.
33
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The type of data and level of specificity required is teased on the previously defined goals,
scope, boundary, and intended application of the inventory data.
One method to simplify the data gathering process is to break down the system at
hand into a set of distinct subsystems. A "subsystem" is defined as an individual step or
process that is part of the defined system. Each subsystem will have a distinct set of
inputs and outputs that can be described in the inventory analysis. For example, although
several components make up the life cycle of coating systems, the manufacturing stage of
a particular coating might occur within a single facility. This single facility can be
viewed as a subsystem (see Figure 4), so data can be gathered on all the manufacturing
steps together. This example draws the subsystem boundary around the entire group of
manufacturing steps within a given facility and not around each individual manufacturing
step.
After identifying subsystem boundaries, the practitioner can collect the raw input
and output data. To help manage potentially large amounts of data, the practitioner can
organize the data into a chart or table like Table 3.
Energy
Raw Materials/
Resources
Materials
Subsystem X
Air
Emissions
Water
Effluents
Solid
Waste
Co-products
• Products
Other
Outputs
Figure 4. Generic Subsystem*
6.) Develop Stand-Alone Subsystem Data. To represent the inputs and outputs
of the entire system, the practitioner must aggregate the individual subsystem data. Stand-
alone subsystem data refers to standardized or normalized data that is amenable to
aggregation with other subsystem data. The primary goals of developing stand alone data
are the following:
• To present data for each subsystem consistently by reporting the same product
inputs and outputs from each subsystem.
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TABLE 3. SUBSYSTEM WORKSHEET FOR MANAGING DATA4
LIFE-CYCLE INVENTORY CHECKLIST PART II - SUBSYSTEM WORKSHEET
Inventory of:
Life-Cycle Stage Description:
Date:
Quality
SUBSYSTEM DESCRIPTION:
Data Value*
Type-
Assurance Approve
Data' Age/Scope
:
Quality Measures"
SUBSYSTEM INPUTS
Materials
Process
Other"
Energy
Process
Pre combustion
Water Usage
Process
Fuel-related
SUBSYSTEM OUTPUTS
Product
Coproducts'
Air Emissions
Process
Fuel-related
Water Effluents
Process
Fuel-related
Solid Waste
Process
Fuel-related
Capital Repl.
Transportation
Personnel
• Include units.
• Indicate whether data are ad
a specific manufacturer or ta
Atlanta facility wastewater p«
and indicate the period covet
* Ust measures of data quality
* Include nontraditional Inputs
' If coproduct allocation metho
tual measurements, engineering estimates, or theoretical or published values and whether the numbers are from
Eflity, or whether they represent industry-average values. Ust a specific source If pertinent (e.g., 'obtained from
nmtt monitoring data").
re al available, regulated only, or selected. Designate data as to geographic specificity, e.g., North America.
«d (e.g.. average of monthly for 1991).
available for the data item (e.g., accuracy, precision, representativeness, consistency-checked, other, or none).
[e.g., land use) when appropriate and necessary.
d was applied, indicate basis in quality measures column (e.g.. weight).
35
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• To develop the data in terms of the life cycle of only the product examined in
the inventory analysis.
Two main activities need to be undertaken to achieve these goals. First, the
practitioner must translate the input and output data from each subsystem to the same
unit of production or time, as well as to the same unit of measure (e.g., pounds, tons,
gallons). Second, the practitioner must identify and distinguish inputs and outputs
attributable to the product in question from inputs and outputs attributable to the
production of coproducts. Commonly called coproduct allocation, this process is usually
based on relative weight.
7.) Construct a Computational Model. A computational model is needed that
incorporates the normalized data and material flows into a computational framework using
a computer spreadsheet or other accounting technique. The systems data that result from
the model's computations will yield the total result for the inputs and outputs of the
system in question.
The computational model uses "proportionality factors," which are quantitative
relationships that reflect the relative contributions of the subsystems to the total system.
For example, data gathered for manufacturing conventional coatings may have been based
on 1,000 gallons of solvent. If the total system is based on 1,000 gallons of conventional
coating (which is 70 percent solvents, 30 percent solids), the contribution of solvent to the
total system is 0.70 times 1,000, or 700 gallons.
8.) Present the Results in a Transparent Manner. Transparency in this context
refers to clearly communicating such aspects as the scope, system boundaries, data
sources, methodologies used, limitations, and assumptions of the analysis. A tabular
presentation format may best communicate results; however, the tables' format will vary
between studies. Summary tables such as Tables 2 and 3 may be appropriate for
illustrating results. In any case, the format for communicating life cycle inventory
analysis results should be consistent with both the purpose of the inventory analysis and
the goals and scope of the LCA in general.
Impact Assessment
Life cycle impact assessment is a systematic process, quantitative and/or
qualitative, that identifies and describes potential environmental and human health impacts
associated with the inputs and outputs of a given system. Although life cycle inventory
analysis is well developed, life cycle impact assessment is in its infancy, so methodologies
are either undeveloped or untried. Therefore, we only briefly describe this component.
To date, most LCAs have been strictly life cycle inventory analyses with no
explicit impact assessment. These studies often implicitly interpret life cycle inventory
results in a context that implies impacts. Failing to consider the methods used to evaluate
and weight or rank the life cycle inventory items may convey that all inventory items
have relatively similar impact potentials. Life cycle impact assessment makes explicit the
methods used to assess the potential impacts resulting from a given system.
36
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Life cycle impact assessment is fairly well developed on a conceptual level. A
three-phase conceptual framework, developed by the Society of Environmental Toxicology
and Chemistry (SETAC)5, has been used as a basis for developing life cycle impact
assessment. A variation of these three phases contains the following activities:
• Classification: The process of assigning and initially aggregating life cycle
inventory data to relatively homogeneous groupings of potential impacts of
concern (e.g., photochemical smog, lung disease, fossil fuel depletion)—called
assessment endpoints—within primary impact categories (natural environment,
human health, and natural resources impacts).
• Characterization: Analyzing and possibly estimating the magnitude of
potential impacts—called measurement endpoints—as actual or surrogate
measures of assessment endpoints that were identified in the classification
phase. Characterization involves using specific impact assessment tools known
as conversion models and impact descriptors.
• Valuation: The explicit and collective process of assigning relative values
and/or weights to potential impacts of concern (assessment endpoints) using
formal valuation methods.
Figure 5 provides a conceptual schematic of these three stages. As illustrated in
Figure 5, the sequence from the life cycle inventory to the improvement component is not
necessarily linear, which is consistent with the three-component LCA triangle in Figure 1.
The sequence involves interrelationships and feedback loops among the major
components. For example, opportunities for environmental improvement can be realized
at any phase of the LCA, but unplanned modifications may entail revisiting previously
completed components.
Unlike other forms of impact assessment, life cycle impact assessment does not
necessarily attempt to quantify actual impacts associated with a system. Instead, life cycle
impact assessment attempts to establish a link between the inputs and outputs of a system
and potential impacts. The ability to establish this link depends on the availability and
use of specific impact assessment tools—called conversion models—to estimate the
magnitude of the contribution of specific life cycle inventory items to potential impacts of
concern (assessment endpoints).
37
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Identify Potential
Impacts
Select Assessment
Endpoints
Classify Inventory Items
by Assessment Endpoint
Select Measurement
Endpoints
Apply Conversion Models
Develop Impact Descriptors
CO
CO
UJ
u
Apply Weighting/Ranking
Methods
Life Cycle Improvement
Assessment
Figure 5. Life Cycle Impact Assessment Conceptual Framework
38
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Recent forums (SETAC Life Cycle Impact Analysis Workshop in February 1992
and the SETAC Life Cycle Data Quality Workshop in October 1992) have identified a
five-level tiered hierarchy of conversion models, shown in Figure 6.
ThKS: Site-Specific Exposure/Effects
sment
Models determine the actual impact* of Ma cycle
inventory data based on sle-speclic fate, transport.
and impact Information lor the relevant impact area.
Tier 4: Generic Exposure/Effects Aa*aaamant
Models estimate potential ImpacU on the back of generic
environmental and human health Mormatioa Generic environmental
information may consist at generic lata, transport, and impact data lor
potential individual, population, or ecosystem knpacts.
Her 3: Inherent Chemical Properties Aiienment
Modafc aggregate He cycle invenlory data on the back of inheranl
chemical properties, such as loricity, persistence, and bioaccumulation.
Categories of inherent chemical properties may then be used to
determine relative impact potentials.
Tier 2: Impact Equivalency Assessment
Models use derived equivalency (actors as a basis on which to aggregate We
cycle inventory data. Aggregated equivalency (actors may then be used to
estimate relatively homogeneous measures ol potential impacts.
Tierl: Loading Assessment
Models 1st and possbry group lie cyde inventory data in terms ol potential impacts.
LJe cycle invenlory data may also be aggregated into stressor groups that can be
linked to potential impacts.
Figure 6. Five-Level Tiered Hierarchy of Conversion Models
One major constraint currently limits the applicability of conversion models—the
lack of data on many environmental and human health effects. The general consensus is
that the lack of this data limits practitioners to Tier 1- and Tier 2-type conversion models
where impacts are not measured per se. Tiers 3 to 5 conversion models require more site-
specific data as well as additional computational models. Gathering site-specific data and
developing computational models are long-term goals.
Improvement Assessment
The improvement assessment component of LCA is a systematic process that
identifies, evaluates, and implements opportunities for environmental improvements.
Because the improvement component has not yet been developed or even discussed in a
formal public forum, we do not discuss it in this paper. Preliminary discussions on
improvement assessment have recognized that both quantitative and qualitative evaluations
of improvement options may occur in this component. In assessing the two alternative
coating systems, the improvement assessment component might recognize that the powder
coating system not only eliminates VOC emissions but it also uses less energy and labor
and produces less waste products. On a "less is better" basis, the powder coating system
uses less inputs and generates less outputs; therefore, this system may be considered more
39
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environmentally benign than the conventional coating system. In addition, the
improvement assessment might also identify and implement opportunities to further reduce
input use and output production within the powder coating system.
CONCLUSION
In an era of heightened awareness of environmental and human health effects
resulting from products and processes, LCA represents an emerging tool for incorporating
such concerns into decisionmaking processes. This paper outlines the LCA process,
including goal definition and scoping, inventory analysis, impact assessment, and
improvement assessment. Techniques used in this process could be applied to assess
alternative coating systems to minimize potential impacts to the environment and/or
human health.
Although much of LCA methodology remains to be developed, LCA currently may
be used as both a screening tool for assessing potential environmental and human health
impacts and a tool for making explicit those methods used to evaluate alternative coating
systems that may have relatively similar or largely different components and/or effects.
REFERENCES
1. Henn, Carl L. The New Economics of Life Cycle Thinking. Unpublished paper.
Society of Logistics Engineers, New Brunswick, New Jersey.
2. Pojasek, Robert B. Spray Painting: The Search for the Right Answer. Pollution
Prevention, (Spring):243-248, 1992.
3. Rauch Associates, Inc. The Rauch Guide to the U.S. Paint Industry. Bridgewater,
New Jersey, 1990.
4. U.S. Environmental Protection Agency. Life-Cycle Assessment: Inventory Guidelines
and Principles. EPA/600/R-92/245. Washington, DC, 1993.
5. Fava, James A., Richard Denison, Bruce Jones, Mary Ann Curran, Bruce Vigon,
Susan Selke, and James Barnem. A Technical Framework for Life-Cycle
Assessments. Society of Environmental Toxicology and Chemistry, Pensacola,
Florida, January 1991.
6. Canadian Standards Association. Environmental Life Cycle Assessment. Draft report.
Canadian Standards Association, Ontario (Toronto), Canada, 1992.
40
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SESSION 2
TECHNOLOGIES
PAPERS PRESENTED:
"Radiation Curing Technology: Ultraviolet (UV) and Electron Beam (EB) Processing"
by
Richard W. Stowe
Fusion UV Curing Systems
Rockville, Maryland
"Environmental Compliant Thermoplastic Powder Coating"
by
David F. Ellicks
Department of the Air Force
Air Force Corrosion Program Office
Robins AFB, Georgia
"Supercritical Fluid Spray Application of Low-Pollution Coatings for Plastic Substrates"
by
Wayne Paul Miller
Kenneth A. Nielsen
Union Carbide Corporation
South Charleston, West Virginia
and
Tom Morrison
Red Spot Paint & Varnish Company, Inc.
Evansville, Indiana
'Utilizing Dispersion Resins with Inorganic Solids in a New Formulary Blending Process
to Achieve Synergistic Results of Performance"
(Expanded abstract; paper not available.)
by
Philip W. Coscia
Resources Conservatory International
Gustine, California
41
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
RADIATION CURING TECHNOLOGY
Ultraviolet (UV) and Electron Beam (EB) Processing
Richard W. Stowe
Fusion UV Curing Systems
7600 Standish Place
Rockville, MD 20855
Radiation curing of polymeric materials is an efficient and
relatively low temperature electricity-based technology with many
applications in coating, printing, adhesives, electronics, and
communication material. Radiation curing, which includes
Ultraviolet Curing and Electron Beam technologies, can improve
the overall physical or chemical properties of polymeric
materials and produce superior results in bonding, surface
finish, and durability to those of other technologies. Speed
and controllability in these applications, suggest an increasing
market for this electrotechnology in manufacturing worldwide.
BENEFITS
Both UV or EB Curing are highly desirable for processing,
owing to benefits of productivity as well as advantages of being
"clean" technologies. These radiation processes have a number of
key attributes; they are:
• a solventless process — cure is by polymerization
rather than by evaporation, so VOC emissions are
eliminated;
• a lov temperature process — heat is not required;
• a high speed process — cure is nearly instantaneous;
• an energy-efficient process — energy is invested only in
the curing reaction, not in heating;
• easily controlled — inks and coatings do not "dry," so
do not set up in printing/coating equipment.
APPLICATIONS
Radiation-processing technologies offer several major
advantages over other production methods. These benefits include
rapid curing, low process temperatures, the absence of pollution,
and substantially lower energy costs, as well as high-quality and
specialized products. Typical product lines involve coatings (on
wood, metal, paper, and plastic), inks (for letterpress,
lithographic, gravure, and screen printing), and adhesives (for
film, foil, or paper substrates). The industries using these
technologies are diverse and varied; they include electronics,
fiber optics, flooring, packaging, plastics, and printing.
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MATERIALS
The essential ingredients of a radiation-curable material
are:
(1) Oligomers — 30-90% concentration; completely reacted upon
cure; primarily provide film properties such as flexibility,
hardness, and chemical resistance; (equivalent to "resins"
of conventional coatings) There are a number of choices of
types which provide a variety of features and properties of
the uncured and cured material, such as viscosity, cure
speed, hardness, toughness, flexibility, weathering, etc.
(2) Monomers — 10-70% concentration; completely reacted upon
cure; controls viscosity and polymer chain formation;
(equivalent to "solvent" in conventional materials EXCEPT
that it is completely reacted)
(3) Photoinitiator (UV curing only) — 1-5% concentration; a
photo-active material which responds to (UV) light and
initiates chain formation.
(4) Additives and pigments — conventional materials to alter
stability, adhesion, tack, or appearance.
TECHNOLOGY: UV CURING
UV lamps are generally of two types: (1) Medium pressure
mercury vapor arc lamps (usually called "arc lamps"), or (2)
Medium pressure mercury vapor microwave-powered lamps (called
"microwave powered lamps" or "electrodeless lamps").
The UV energy produced by the lamp bulb is focussed by a
reflector onto a (moving) surface. The UV energy striking the
surface causes the photoinitiator to trigger the polymerization
reaction. The material is usually solidified ("dry") when it
exits the cure zone.
Lamps are characterized by the UV light intensity at the
work surface (irradiance), measured in Watts per square
centimeter (W/cm2). Cure dose is a function of time (or process
speed) and is measured in Joules per square centimeter (J/cm2).
By using multiple lamps, the process width can be extended
without limit.
A light enclosure is required to eliminate stray UV light
and to provide protection to personnel from exposure to UV.
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TECHNOLOGY: BB CURING
Electrons generated by a hot filament and cathode are
accelerated by a high voltage to produce a flood of high energy
electrons which are concentrated into a beam onto a (moving)
surface. The energy of the electrons is a function of the
accelerating voltage. Electron beam accelerators are
characterized by their accelerating voltage: 300 kV or less is
referred to as "low energy." Most curing accelerators are in
this range. Process width is usually 130 inches or less.
Electrons striking and penetrating the uncured material
cause a direct initiation of the cross-linking reaction in the
material, and the material is immediately polymerized.
The dose (D), in megarads, received by a material is
characterized by the electron current (I), the velocity of the
process (S), and a factor (k) which is a function of the
accelerator voltage, geometry, width and distance:
D(Mrad) =
The curing zone is surrounded by an enclosure to contain an
inert (nitrogen) atmosphere. It is necessary to displace oxygen,
which interferes with the curing reaction at the surface of high
speed materials. Electrons striking oxygen molecules would also
produce ozone. The enclosure is also shielded to prevent escape
of radiation produced by the high energy electrons.
PRODUCT APPLICATIONS FOR DV PROCESSING
• Printing and Publishing
Book and magazine covers
Brochures and promotional materials
Compact disc boxes and album covers
- Menus
• Consumer Products
Eyeglass lenses
Trophies and plagues
- Tape measures
• Wide web converting
Silicone release films
Vinyl flooring no-wax finish
Solar reflective films
Vinyl woodgrain laminating films
45
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PRODUCT APPLICATIONS FOR 0V PROCESSING (continued)
• Business Forms
Direct nail
Catalogs
Business forms
Sweepstakes mailings
• Narrow web converting
Labels and tags
Bar code printing
Lottery tickets
Stickers and decals
• Plastics
Headlamp lenses and bodies
Decorative caps and containers
Auto body moldings
• Medical devices
disposable syringes
Transdermal patches
Catheters
• Plastic container decoration
Shampoo and toiletry bottles
Toothpaste tubes
Styrofoam cups and containers
• Wood
Fillers and sealers for plywood and particle board
High gloss finishes on case goods
Wood flooring strips and parquet
• Electronics
Component marking
Conductive inks
Conformal coatings
• Metal Containers
Two piece (aluminum) beer and beverage cans
Three-piece (steel) cans and containers
Metal boxes
• Telecommunications
Optical fiber coatings
Printing on wire and cable insulation
Optical ribbons, cables and fiber coloring
46
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PRODUCT APPLICATIONS 70R ELECTRON BEAM PROCESSING
Curing ("drying"!
• Inks and coatings in offset lithography (e.g., printing
folding cartons and flexible packaging)
• coatings on wood, Masonite or particle board to produce
decorative panels
• Adhesives in laminating operations
• Silicone coatings on controlled- release products
(e.g., label stock) and magnetic coatings on recording
tapes and discs
Crosslinking
• Plastic films for high strength and temperature
packaging materials (e.g., shrink wrap)
• Heat shrink tubing for electronic applications
• Wire/cable insulation to increase chemical resistance
and allowable operating temperature
Sterilization
• Medical products
Electron beam (EB) and Ultraviolet (UV) processing are
sometimes considered to be competitive technologies, but in most
cases, specific manufacturing requirements provide a clear
differentiation between the two approaches, and they tend to be
complementary. In some instances they may both be required.
RECYCLING OF RADIATION-CURED PRINTED MATERIAL
A study recently conducted by the Beloit Corporation,
sponsored by RadTech International, found that all of the (UV/EB)
ink/coating combinations were recyclable into board grades.
Furthermore, the study proved that for recycling into tissue
grades, all materials require a system containing flotation while
most also require centrifugal cleaners.
In addition, UV inks and sheetfed litho inks with water-
based coating also require dispersion, a common component in
today's recycling mills, for recycling into tissue grades.
47
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For recycling into fine paper grades, most ink/coating
combinations require dispersion and additional flotation.
Hence the Beloit study's conclusion: UV/EB printed and
coated paper can be recycled into tissue and/or paper grades
using commercially available equipment. In fact, UV/EB cured
paper is just as recyclable as other materials.
UV and EB MARKETS
U.S. Market for Radiation Curable Coatings^
Inks and Adhesives. by End-user Industry
(Value $mm)
Industry
Electrical / Electronics
Packaging
Graphic Arts
Wood furniture & Construction
Automotive
1991
74
67
31
49
8.4
1996
140
103
49
69
12.7
% Change
90%
54%
58%
41%
51%
Source: Frost and Sullivan, Inc. - 1992
RECENT TREND AND SHARE
Annual Coatings Market Survey
(percent of total volume)
TYPE OF COATING USED
Convent i ona 1
High-solids
Two-component
Powder
Haterborne
Vapor-cure
Radiation-cure
other
1989
47.8
14.9
12.2
11.1
9.1
1.6
1.4
1.9
1990
46.0
16.5
12.9
11.5
11.2
.7
.9
3.3
1991
41.6
16.4
11.6
12.8
11.8
1.4
2.0
2.5
1992
32.5
16.3
11.5
16.7
16.9
1.1
2.3
2.5
Source: Industrial Finishing - January 1992
48
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"Radcure coatings today comprise about 3% ($300 million) of
the U.S. industrial coating market ($10 billion). Indeed, (TV and
EB coatings that cure instantly, rapidly and with minimal VOC
certainly have a bright future. The share could reach 10% ($1
billion) by 2000".
Source: Industrial Finishing - May, 1992
CONCLUSION
Radiation-processing technologies offer several major
advantages over other production methods. These benefits include
rapid curing, low process temperatures, the absence of pollution,
and substantially lower energy costs, as well as high-quality and
specialized products. Typical product lines involve coatings (on
wood, metal, paper, and plastic), inks (for letterpress,
lithographic, gravure, and screen printing), and adhesives (for
film, foil, or paper substrates). The industries using these
technologies are diverse and varied; they include electronics,
fiber optics, flooring, packaging, plastics, and printing. While
still minor manufacturing techniques, their industrial use is
expected to expand greatly, with a continued annual growth of 15
to 20%.
49
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50
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
ENVIRONMENTAL COMPLIANT
THERMOPLASTIC POWDER COATING
David F. Ellicks
USAF
Air Force Corrosion Program Office
WR-ALC/CNC
215 Page Road
Suite 232
Robins AFB.GA 31098-1662
51
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INTRODUCTION
In the early 1970s, inhibited epoxy primer and aliphatic polyurethane
paint systems were applied to a majority of Air Force weapon systems. This
coating effectively reduced the level of corrosion on the exterior surfaces of
aircraft. This resulted from "built-in" corrosion inhibitors and the
coating's capacity to bend without cracking as the surfaces of the aircraft
flexed during flight. The Air Force recognized the 1980's as the decade of
environmental awareness. The 1990's, on the other hand, will introduce the
new technologies required to fully address all the environmental considera-
tions. The current painting operations generate carcinogenic substances
(methylene diisocyanates), air pollution (volatile organic compounds from
solvent-borne coatings), and hazardous wastes (paint waste containing
strontium, barium, or zinc chromates and cadmium) . Historically, the Air
Force has used primers and topcoats because of the excellent corrosion
protection they provide. The Air Force, in general, and Warner Robins Air
Logistics Center, in particular, have been striving toward the elimination of
isocynates, volatile organic compounds, and heavy metals. The goal is for the
paint operation to conform to the increasingly stricter environmental and
health requirements. The painting operation requires very expensive
facilities (explosion proof lighting and fixtures, drainage system, and one
pass heating/cooling ventilation systems), hazardous waste disposal
facilities, air supplied respirator devices, medical examinations, and
extensive training. In addition, special high volume/low pressure paint
spraying equipment and high solids solvent-borne coating systems are being
used to help reduce volatile organic compounds.
In order to reduce the environmental/health hazards and the cost of
disposing of the hazardous waste, the Air Force Corrosion Program Office
continually evaluates potential new coatings and application techniques. One
new and promising coating and application technique is Thermoplastic Powder
Coating (TPC) applied through flame spraying equipment. This paper describes
the Air Force Corrosion Program Office's initial evaluation, economic
analysis, environmental analysis, and the preliminary results from
applications testing done at Warner Robins Air Logistics Center, Robins
Air Force Base, Georgia.
BACKGROUND
There has been a long-term problem at many Air Force bases with the use
of hazardous coatings/coatings removal materials and the lack of adequate
facilities for performing corrosion prevention and control processes on
nonpowered aerospace ground equipment, munitions handling equipment, nonfueled
industrial vehicles, trailers, containers, components, and civil engineering
real property facilities/structures. Standard coatings are not meeting the
durability and maintainability requirements of the units and pose a hazard
both to the health of personnel and the environment. Lack of authorized and
available corrosion facilities in the munitions or aerospace ground support
equipment organizational units for depainting/repainting of the end items and
parts is a problem at many bases. Keeping this in mind, the Air Force
Corrosion Program Office is always looking for new technologies to protect Air
Force assets from corrosion damage. We are also mindful that the life cycle
environmental considerations must be integrated into product/process
engineering design procedures.
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THERMOPLASTIC PONDER COATING AND APPLICATION EQUIPMENT SYSTEM DEFINITION AND
EVALUATION
System Definition
Currently, there are three common techniques for applying powder
coatings: electrostatic deposition, fluidized bed dipping and flame spraying.
Electrostatic deposition is accomplished by immersing an electrically grounded
part in a fog of powder sprayed from an application gun which transfers a
static charge to the powder. The powder is attracted to the part and clings
to the surface. The coated part is then heated (oven or infrared lamps) to
bake and fuse the coating to the part. Fluidized bed coating involves dipping
preheated parts into a column of powder which has been fluidized (agitated) by
passing air up through the column. The heat retained by the part serves to
melt and fuse the coating. In flame spraying, powder is blown through a
flame, melted, and directed onto the material being coated.
The TPC and application equipment system is similar to metal flame
spraying equipment with thermoplastic or thermoset powder replacing the metal
powder. Some of this equipment is expensive and too complicated to use at
field-level bases. The coating process is simple. In general, the bare metal
surface to be coated is first inspected for cleaniness (oils, hydraulic
fluids, etc.) and then preheated to approximately 175 degrees Fahrenheit with
the application flame gun or nozzle to drive off moisture and to ensure that
the applied plastic will flow smoothly. The preheating step is followed by
application of the finely ground, pigmented polymer to the desired thickness
either as solid or molten powder. The final step is the continued heating of
the applied polymer to insure proper flow-out to the optimum coating
temperature range of 320 to 425 degrees Fahrenheit, as monitored by a
hand-held infrared pyrometer. After the coating cools, the painting operation
is complete. For the thermoplastic powders, no chemical reaction or change in
the molecular structure occurs during the coating process. Therefore, these
coatings have the potential for easy repair if damaged by simply reheating or
re-applying additional powder. The coating is soft, one coat, glossy, thick
(10-12 mils), durable, easy to apply, repairable, safe for workers, and
environmentally compliant.
The thermoplastic powder is generated by grinding polymer pellets at
cryogenic temperatures using liquid nitrogen as a refrigerant. Originally,
Envelon powder was supplied directly by Dow Chemical Corporation; however, Dow
has now licensed that process to Morton, International, a major commercial
supplier of industrial powder coating materials. Plastic Flamecoat Systems
(PFS) of Houston, Texas (an alternate TPC equipment manufacturer) grinds
DuPont Nucrel and is currently the only source for this powder. The
Dow/Morton product is a "melt blend" material in which pigments, UV
stabilizers, and other additives are blended with melted polymer before
grinding. The DuPont/PFS powder is "dry blended" by mixing additives with the
powder after grinding. Both powders cost relatively more than the convential
solvent-borne coating systems. Both materials are considered "environmentally
compliant" by current EPA federal and state regulations.
Both the Dow and DuPont powders may be obtained in a range of "melt
index" values. Low melt index polymers are more viscous at any given
53
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temperature than are high melt index polymers. In general, the low melt index
powders yield tougher coatings but are more difficult to apply because they
require higher temperatures to achieve flow-out during application. Both
polymers melt at about 300 degrees Fahrenheit and flow over a substrate that
has been preheated to a temperature of 150 to 175 degrees Fahrenheit. If
coating temperature exceeds 425 degrees Fahrenheit for extended periods of
time (minutes), significant polymer chain cross- linking occurs, and the
coating effectively converts from a thermoplastic to a thermoaet material.
When this happens, field repairability of the coating by reheating is lost.
If coating temperatures exceed 650 degrees Fahrenheit during application, the
polymer is permanently damaged and the coating is destroyed. To avoid
overheating, the coating temperature is carefully monitored by the applicator
with a hand-held infrared pyrometer.
System Evaluation
A TPC application system was selected by the Air Force for a field-level
test program. This system was chosen as the most suitable for evaluating the
current state of flame coating technology and its potential for an alternate
to conventional solvent-borne paint systems. The simplest and most commonly
used TPC flame spray application systems are entirely pneumatic. These
systems require only clean, dry compressed air and fuel (typically liquid
propane) for operation. Powder is stored in a hopper and delivered by hose to
the gun in a stream of compressed air that transports powder from the hopper
with a venturi. Propane is delivered to the gun through a separate hose and
mixed with air at the gun exit where it is ignited. The equipment operator
sets the air, powder, and fuel flow rates with controls located on or near the
gun. The powder/air mixture blows through the flame, melts and flows onto the
surface to be coated.
Dow and DuPont are the two major domestic suppliers of thermoplastic
polymer resins developed for flame spray application. Each manufactures a
similar commercial thermoplastic resin. Dow "Envelon" is an Ethylene Acrylic
Acid (EAA) copolymer. DuPont "Nucrel" is an Ethylene Methacrylic Acid (EMAA)
copolymer. These copolymer formulations were developed to enhance
polyethylene coating adhesion. Dow and DuPont have worked closely with
application equipment manufacturers to develop effective TPC flame spraying
systems. Some equipment suppliers restrict the use of their hardware to
specific polymers. The flame spraying equipment manufactured by American
Thermoplastics, Inc. (AT) of Mesa, Arizona, has been selected for field-level
evaluation at several Air Force bases. AT allows the use of all commercially
available TPC materials; however, the use of Dow Envelon is recommended. Dow
materials were used in this test program.
System Characteristics and Modifications
Of the three flame spraying systems evaluated, the UTP system had the
most sophisticated flame application hardware. UTP uses an electro-pneumatic
system requiring oxygen as well as compressed air and propane. This method
provides a smaller, hotter flame yielding better temperature control and
better flowout of thermoplastic powder. This has lead to the current
development effort focused upon improving flow-out temperature and the spray
pattern. The Air Force is looking at modifying the nozzle to use a premixed
combustion instead of a diffusion flame for better heating control. In
54
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addition, we are seeking modification of the nozzle to change from a circular
to a tapered oval spray pattern to widen the pattern and to improve the
coating uniformity (thickness variations).
Further nozzle development may also be necessary for coating hard-to-reach
areas, e.g., angles, tubing, and grating, found on maintenance stands or other
complex equipment residing in the Air Force inventory.
Thermoplastic powder coatings have notable performance properties that
address the environmental/health problems inherent with standard Air Force
polyurethane coating systems. For example, these coatings exhibit excellent
resistance to various chemicals, solvents, and reagents. This coating should
not be used in contact with chlorinated solvents, fuming or strong oxidizing
acids, aromatic alcohols, or heterocyclic aldehydes. These coatings have
shown excellent abrasion resistance and good barrier qualities to prevent
corrosion, and they are environmentally compliant. These coatings have the
ability to be applied in almost all types of weather in any area, inside or
outside, where it is safe to use a flame. The thermal spray coatings are
proving useful in many Air Force applications. They are not appropriate for
every application. This process does have drawbacks such as incompatibility
with live munitions or combustibles, problems with thin metal and composites,
slow application rate (50 to 100 square feet per hour), high substrate
temperature effecting the heat treatment of alloys, and high material cost.
This information is based on the preliminary laboratory testing using the test
requirements in MIL-C-83286 as a comparison and guide to base our above
conclusions.
Continuing Efforts
Warner Robins Air Logistics Center is pursuing an aggressive program to
test and evaluate thermoplastic powder coating flame spray application methods
with the desire to implement this technology as one of the new alternatives to
solvent-borne coatings. Current efforts involve optimizing the spray nozzle
for better coating applications and developing flameless techniques for
coating with thermoplastic/thermoset powders. The Air Force Corrosion Program
Office will continue to strive to identify a coating system that will provide
corrosion protection while eliminating environmental/health problems
throughout the Air Force.
Conclusions
Thermoplastic powder coating flame spray application methods produce a
simple, highly reliable, safe, environmentally compliant, single coat
capability to augment the standard Air Force epoxy-polyurethane coating
systems. TPC will also eliminate some requirements for several current
maintenance operations, e.g., chemical conversion coatings, long paint drying
times, air supply respirators, and expensive facilities. The need to convert
from standard coating to thermoplastic/thermoset powder coatings is being
driven by the requirement to reduce hazardous wastes, enhance personnel
safety, provide a cleaner environment, and minimize coating facilities.
55
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f AIR FORCE
CORROSION PROGRAM
THERMOPLASTIC
POWDER COATINGS
(TPC)
Briefer:
DAVID F. ELLICKS
Materials/Mechanical Engineer
Air Force Corrosion Program Office
AFCWIe
AFCorr Data Disk 2
Briefing rn: afcorr
-------
FORCE
in
CORROSION PROGRAM
OBJECTIVE
OBJECTIVE
EVALUATE THE FLAME SPRAYED TPC
TECHNOLOGY AS AN ALTERNATIVE
TO STANDARD AIR FORCE EPOXY/
POLYURETHANE COATING SYSTEM
POLYETHYLENE PLASTIC
•ETHYLENE ACRYLIC ACID COPOLYMER (DOW) (MORTON)
-ETHYLENE METHACRYLIC ACID COPOLYMER (DUPONT)
fn: blank
AFCORR Data Disk 2
As Of:
-------
f.AIR FORCE
CORROSION PROGRAM
APPROACH
APPROACH
ENGINEERING STUDY--STARTED 1 OCT 91
CONTRACTOR: SCIENCE APPLICATIONS
INTERNATIONAL CORPORATION (SAIC)
THREE PHASES:
* PHASE I - INDUSTRY SURVEY/SITE VISITS
* PHASE II - EQUIPMENT/COATINGS EVALUATION
* PHASE III - EQUIPMENT/COATINGS FIELD TESTS
tm blonk AfCORR Data Disk 2 As Of
-------
f AR FORCE
APPLICATION
tn
VO
CORROSION PROGRAM
EQUIPMENT APPLICATION
NONPOWERED AEROSPACE GROUND EQUIPMENT
MUNITIONS HANDLING EQUIPMENT
NONFUELED INDUSTRIAL VEHICLES
TRAILERS
COMPONENTS
fn: blank AFCORR 6afa Disk JAs 01:
-------
f AIR FORCE
BENEFITS
CORROSION PROGRAM
POTENTIAL BENEFITS
ONE COAT
NO/LOW VOLATILE ORGANIC COMPOUNDS (VOCs)
NO TOXIC FUMES
NO HAZARDOUS WASTE
FIELD APPLIED/REPAIRABLE COATING
EXTENDED SHELF LIFE
REDUCE VENTILATION/FACILITIES REQUIRED
NO CURE TIME - COOLING TIME
rn7 blank AFCORR Data Bisk 2 As 01:
-------
( AIR FORCE
DRAWBACKS
CORROSION PROGRAM
DRAWBACKS
NO CORROSION INHIBITORS
THICK
ORANGE PEEL APPEARANCE
SLOW COATING RATE
LIMITED USE
HIGH TEMPERATURE DEGRADATION
ROUND SPRAY PATTERN (NOT OVAL)
frn blank AfCORR Data bisk 2 As
-------
f AR FORCE
PROCEDURE
N)
CORROSION PROGRAM
TPC APPLICATION PROCEDURES
PREPARE SURFACE TO BARE METAL
INSPECT FOR CLEANINESS
PREHEAT SURFACE TO 150 - 170 DEGREES F
START APPLYING TPC
INSURE PROPER FLOW-OUT TEMPERTURE (350-400 DEGREES F)
- USING HAND-HELD INFRARED PYROMETER
AFTER COATING COOLS, ITEM READY TO USE
fn: blank AFCOftft Data Disk 2 As Of:
-------
[ AIR FORCE
^ TEST SITES
CORROSION PROGRAM
FIELD EVALUATION SITES
EGLIN AFB FLORIDA
ANDERSEN AFB GUAM
KADENA AFB JAPAN
ELEMENDORF AFB AK
tn: blank AFCORR Data Disk 2As Of:
-------
[ AR FORCE
O
CORROSION PROGRAM
PRESENT STATUS
STATUS
PHASE II MID AUG 93
PHASE III DEC 93
PHASE IV DEC 94
fn: blank AFCOftft Data Disk 2 As Of:
-------
(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
SUPERCRITICAL FLUID SPRAY APPLICATION
OF LOW-POLLUTION COATINGS
FOR PLASTIC SUBSTRATES
Wayne Paul Miller
Kenneth A. Nielsen
Union Carbide Corporation
P.O. Box 8361
South Charleston, WV 25303
Tom Morrison
Red Spot Paint & Varnish Co., Inc.
P.O. Box 418
Evansville, IN 47703
INTRODUCTION
Increasing pressure from groups concerned about the fate of the environment have helped
spawn a new generation of heightened governmental regulation designed to significantly reduce the
amounts of volatile organic compounds (VOC) emitted. The coatings industry has been the target of
many of these regulations. As a result, coatings formulators and applicators have had to develop new
methods or products to remain compliant. Very often the resulting coatings have been dramatically
inferior to their conventional organic solvent-borne precursors in terms of economics, appearance,
performance, and convenience.
Two strategies are prevalent today in reducing the amount of organic solvent emissions from
coatings. The first, removing the organic solvent from the coating prior to the application, is the most
widely practiced. The second, removing the solvent from the air handling system after it has been
released from the coating and prior to release to the outside atmosphere, is less widely practiced
because of the high capital and operating costs involved, and the intimidating level of sophistication. It
is also inappropriate in those states that regulate emissions based on die applied VOC level.
Additionally, with the fuel tax strategy proposed by the current administration, fuel-intensive systems,
such as incinerators, are less attractive.
Removing the solvents prior to the application typically results in viscosity increases in the
coating. The increased viscosity of the coating has dramatically detrimental effects on the
processability, sprayability, and appearance of the coating. To overcome this, formulators have
frequently resorted to reducing the molecular weight of the base resin(s) in the coating in order to keep
the viscosity of the coating low enough to handle. This approach has typically been referred to as high-
solids coatings.
Typically, reactive coatings have suffered less from the high-solids approach than have
conventional lacquer coatings. This has been because the reactive functionality of the base resin
©1993 Union Carbide Corporation
(Reproduced with Permission)
65
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lime required, are costly, and therefore unattractive to many applicators and formulators.
In spite of the many advantages that solvent-borne coatings have, they are typically
characterized by high emissions of volatile organic compounds, and consequently are under increasing
regulatory scrutiny. The development and introduction of the supercritical fluid spray process has not
only allowed this challenge to be overcome, but also allowed for further performance and economical
improvements in solvent-borne coatings for plastics.
SUPERCRITICAL CARBON DIOXIDE AS A COATING SOLVENT
Supercritical fluids are interesting and useful because they have properties that are intermediate
to both gasses and liquids. Because of the high temperatures required to drive normal liquids into the
supercritical regime, compressed gasses are the most widely utilized supercritical fluids. Supercritical
fluids have become increasingly more widely used in a variety of industrial applications within the last
dozen years. Thorough treatments of the properties and uses of supercritical fluids are provided by
Johnston (1) and McHugh and Krukonis (2).
Perhaps the most important property of supercritical fluids is the relationship between density,
and hence solubility, and pressure, and not just temperature. Because supercritical fluids are highly
compressible in nature, significant changes in density (and solubility) can be initiated with relatively
small changes in pressure. Supercritical fluids have lower densities, higher rate of diffusion, lower
viscosities, and higher penetration ability when compared to normal liquid organic solvents. These
properties permit supercritical fluids to penetrate polymer systems and then mix and equilibrate faster
than normal solvents.
Supercritical carbon dioxide is the primary, but not only, supercritical fluid utilized in the
supercritical fluid spray process. Along with the attributes that supercritical carbon dioxide shares with
other supercritical fluids, it has many other significant attributes for use in coatings applications.
1) The critical conditions of carbon dioxide (31 degrees Celsius/88 degrees Fahrenheit,
1070 psi) are easy to obtain. The critical temperature is only slightly above room
temperature, and the critical pressure is well within the designed containment pressure
of typical airless spray equipment.
2) Carbon dioxide is much less toxic than normal organic solvents. It has a high threshold
limit value (TLV) of 5000 parts per million (0.5%). The health effects of carbon
dioxide are slight, when compared to other liquid organic solvents. The concentration
of carbon dioxide observed in the spray booth has been observed to be innocuous in the
range of normal spray operation.
3) Carbon dioxide is non-flammable and mostly inert. Also, the supercritical fluid
compatible coating has a much higher flash point because it has less solvent. This
helps reduce the overall flammability in and around the spray booth and spray line.
Along with the safety benefits of a less flammable area, it can also be less expensive for
insurance purposes.
4) Supercritical carbon dioxide, because of its small molecular size and high solubility,
can easily penetrate most polymer systems to significantly improve the viscosity of
most coating formulations.
68
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S) Carbon dioxide is a low cost commodity chemical that is readily available throughout
the world. It is available in a number of packaging configurations designed to meet the
supply needs of both large- and small-volume coating applicators. Bulk prices of
carbon dioxide are currently less than ten cents per pound in most parts of the country.
6) Carbon dioxide is not considered to be a volatile organic compound by any of the state
or federal regulatory agencies.
REDUCTION OF THE "GREEN HOUSE" EFFECT
The release of carbon dioxide from coatings formulated for spraying with supercritical fluids,
when considered by itself, has little or no effect on local or global environments. For example, an
automotive plant that sprays a top coat on 250,000 automobiles per year would emit less carbon dioxide
than is emitted by soft drinks in the United States in just eight hours. In fact, utilizing carbon dioxide
as a coating solvent actually reduces the amount of "green house* carbon dioxide that is generated
during coating operations.
1) The supercritical fluid spray process uses carbon dioxide created as a byproduct from
natural gas wells, fermentation plants, ammonia plants, and other industrial
applications, which would be released anyway. Therefore, no nevy carbon dioxide is
created by the process.
2) In general, one pound of carbon dioxide is used to replace one pound (or more) of
normal organic solvents in the supercritical fluid spray process. When that one pound
of normal organic solvent is emitted to the atmosphere, it eventually oxidizes to
produce 2.3 to 3.3 pounds of new. carbon dioxide. The one pound of byproduct carbon
dioxide from the supercritical fluid compatible coating system can not further oxidize to
produce any additional carbon dioxide.
3) The high volumes of air from the booths produce a low solvent concentration in the
conventional application. Therefore, thermal oxidation abatement requires the burning
of substantial amounts of fuel. In one automotive paint operation studied, thermal
oxidation abatement produces 18 pounds of new carbon dioxide per pound of organic
solvent.
The amount of recycled carbon dioxide, if used to apply coatings, would certainly be dwarfed
by emissions from other sources. In fact, the total amount of recycled carbon dioxide utilized
industrially in the United States is less than one-third of one percent of the carbon dioxide generated
from coal burning for power plants; oil and natural gas for home heating; automotive fuels; and from
the food industry.
SPRAY GENERATION AND CONDITIONS
The supercritical fluid spray process uses commercial spray equipment specifically designed
and manufactured by the Nordson Corporation, of Amherst, OH, to be compatible with the coating
materials and the properties of supercritical fluids. The supercritical pressures are well within the
69
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standard regime of airless spray, allowing the use of airless spray guns, spray nozzles, hoses, and
pumps. The supercritical temperatures are well within the regime of conventional heated paint
systems. Because there is not a need for any exotic spray equipment, a wide selection of previously
developed accessories for other paint systems can be utilized.
In order for the carbon dioxide, which is a gas under normal conditions, to be mixed with the
coating formulation, it is necessary to pressurize the mixture to maintain the supercritical conditions
necessary to achieve the optimum benefits.
The amount of dissolved supercritical carbon dioxide used to spray any given coating
formulation is a complex function of the solids level, solubility, viscosity characteristics, pigment
loading, and the desired spray pressures and temperatures. Another unique feature of the supercritical
fluid spray process is that the carbon dioxide level in the coating can be used to regulate the film build,
and, to some extent, the dry time of a coating. When spraying at constant pressure through any given
nozzle of fixed flow, as the amount of carbon dioxide increases, the amount of coating material
decreases. Thus, increasing the concentration of carbon dioxide reduces the deposited film thickness.
As the film thickness decreases, so does its dry time. When the film thickness is held constant, usually
by reducing the application rate (traverse speed), the dry time is also decreased somewhat from the
increased loss of solvent in the spray fan. The typical application range is from 10 to SO weight
percent carbon dioxide, and the mixture of carbon dioxide and coating material is usually sprayed as a
single-phase solution.
In order to make the carbon dioxide supercritical, and offset the cooling that occurs as the
carbon dioxide diffuses from the solution and expands as a free gas in the spray, the solution is heated.
Because carbon dioxide solubility is inversely proportional to temperature, and viscosity is directly
proportional to temperature, an optimum spray temperature can exist. The typical range is from 40 to
70 degrees Celsius (100 to 160 degrees Fahrenheit).
The dissolved carbon dioxide usually reduces the spray viscosity to less than SO centipoise.
The coating material usually has a formulated viscosity of from 500 to 3000 centipoise, but materials
with much higher viscosities have been successfully sprayed. The amount of viscosity reduction is a
function of the polymer system, carbon dioxide concentration, temperature, pressure, and solubility.
The viscosity reduction is important because it allows the spray solution to be readily atomized into a
series of fine droplets necessary to deposit a high quality, uniform, film of coating material.
SPRAY CHARACTERISTICS
Supercritical carbon dioxide functions both as a viscosity reducer and a generator of vigorous
atomization. This vigorous atomization is produced by a new mechanism that remedies the defects of
airless spraying and produces a high quality, uniform, film.
Conventional airless spray techniques are often characterized by coarse atomization and
defective spray fans that limit their usefulness to the application of low-quality films. The atomization
mechanism employs a high pressure drop across the spray orifice to generate a high velocity liquid
film. The film typically becomes unstable when the induced shear generated from the high velocity
differential from the film to the surrounding air exceeds the surface tension and cohesive forces in the
film. When the shear is high enough, the film disintegrates in a series of filaments and droplets.
Because the surface tension and cohesive forces in the film are not completely overcome, the resulting
spray consists of non-uniform size droplets and filaments. The spray fans resulting from this
70
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mechanism of atomization tend to contain jets that limit the ability to deposit a high quality, uniform
film.
Supercritical fluid sprays using carbon dioxide have a significantly different atomization
mechanism. The resulting spray is airless in nature, but has all of the desirable traits of the air spray.
but without the high air volumes. A feathered spray, with the spatial uniformity of fine droplet sizes
necessary for obtaining high quality films and high transfer efficiencies, is produced from the vigorous
decompressive atomization provided by the supercritical carbon dioxide.
The vigorous decompressive atomization is believed to be produced when the dissolved
supercritical carbon dioxide in the spray solution suddenly becomes exceedingly supersaturated as the
spray exits the nozzle and undergoes a rapid and large pressure drop. The dissolved carbon dioxide is
driven forcefully to the gaseous state. The rapid gasification of the carbon dioxide overwhelms the
surface tension and cohesive forces of the spray solution before an extensive liquid film can form at the
nozzle. By disrupting the formation of the liquid film, the defects of the airless film are avoided.
Because the fan is no longer constrained by the surface tension and cohesive forces of the airless fan, a
wider fan can be generated at the nozzle exit. This permits the formation of a rounded parabolic-
shaped spray fan with high uniformity of droplet sizes. The fan is characterized by tapered edges
similar to those of conventional air spray fans. The tapered edges permit the coating material to be
deposited uniformly in a wide central region, with progressively less coating deposited towards the
edges of the fan. This is particularly desirable when there is a need to overlap adjacent layers of
sprayed coating to produce a uniform film thickness. Fan widths of the spray are regulated by nozzle
selection, as is done with conventional airless spray.
Laser light scattering analysis has shown that the typical supercritical fluid spray fan has
atomized droplets that range in size from 20 to SO microns. This is dramatically smaller than the
coarser atomization (70 to ISO microns) measured for normal airless spray fans.
Additionally, the decompressively atomized droplets decelerate rapidly after exiting the spray
nozzle to provide a soft spray with low deposition velocities. The shear induced by the decompressive
atomization, which causes the droplets to leave the nozzle at wide angles to make the parabolic fan,
creates a large braking force to the droplet. Additionally, much of the droplets momentum is dissipated
by the diffusion of carbon dioxide. One acrylic coating was measured to have a superficial spray
velocity of 82 meters per second (266 feet per second) at the nozzle. At typical spray distances of 30
to 40 centimeters (11.75 to 1S.7S inches), the average velocity had dropped to seven meters per second
(23 feet per second). The maximum droplet velocity is only 10 meters per second (33 feet per second).
Additional evidence of the rapid release of the carbon dioxide can be found by observing the
rapid cooling of the heated spray that occurs at very short distances from the spray nozzle. The
cooling of the decompressively atomized spray occurs much faster than the cooling of conventional
heated sprays. A conventional airless spray, heated to 60 degree Celsius (140 degrees Fahrenheit),
does not cool back to ambient temperature until it is almost eight inches from the nozzle. The
decompressively atomized spray, heated to the same temperature, reaches ambient temperature within
less than one inch of the nozzle. This rapid cooling is important because it reduces the amount of
solvent that evaporates from the spray, permits more efficient solvent use, and reduces exposure of
workers in the spray area to solvent vapors.
71
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TRANSFER EFFICIENCY
In order for the full benefits of VOC reduction to be realized, it is also necessary to achieve
high transfer efficiencies. Because transfer efficiency depends on a large number of variables relevant
to the application for which it is measured, it is not possible to compare the efficiencies of one
application to those of another. In order to obtain meaningful values, it is necessary to measure
efficiencies in situ. It is also easy to be mislead if maximum values of one application method are
compared to those of another if the quality of the applied film on the pan is disregarded. For example,
larger droplet sizes are easier to deposit than smaller droplet sizes, but typically provide a lower quality
film.
Both independent laboratory testing and commercial production performance measurements
have demonstrated that the supercritical fluid spray process can provide improved coating appearance
and performance without sacrificing material utilization, which has been the traditional trait of previous
spray processes designed to reduce volatile emission.
One of the major spray equipment companies made a thorough examination of the transfer
efficiencies of the supercritical fluid spray process. The test procedure that they utilized involved
spraying spaced panel targets on a conveyor line. The results showed that the supercritical spray
process provided significantly superior transfer efficiency when compared to air spray systems. The
transfer efficiencies of the air-assisted airless spray system and the supercritical fluid spray process, at
spray pressures of 1200 to 1500 psi, were not dramatically different. In another test, the transfer
efficiency of the decompressive spray was measured by foiling an entire automobile body and spraying
it using the supercritical fluid spray process. The overall transfer efficiency measured in the test was
eighty percent.
In addition to measuring transfer efficiencies, it is useful to consider the amount of coating
solids used per part sprayed. In another study, the supercritical fluid spray process was compared to a
high-volume, low pressure (HVLP) spray system. The conventional formulation was sprayed at
nineteen weight percent solids. The coating formulated for use with the supercritical fluid spray
process contained forty-two weight percent solids, which yielded a sixty-seven percent solvent
reduction from the conventional formulation. Transfer efficiencies were measured by spraying a series
of flat parts 20 x 16 inches in size. The transfer efficiency of the supercritical fluid spray process was
measured to be five to eight percentage points lower than for the HVLP spray because of the smaller
droplet size. However, comparison of the production sprays showed that the parts sprayed with the
supercritical fluid spray process demonstrated an improved coating appearance with thinner film builds.
This resulted in an overall twenty-seven percent reduction in coating solids usage, and a realized
solvent usage reduction of seventy-six percent when compared to the HVLP spray system.
At one commercial installation of the supercritical fluid spray process, the amount of solvent
used per part sprayed is sixty percent less than was experienced prior to conversion of the spray line
from the air-assisted airless spray process. This solvent reduction is only slightly less than the solvent
reduction in the reformulated coating. However, the parts sprayed by the supercritical fluid spray
process have a superior appearance to those sprayed by air-assisted airless spray. Additionally, higher
film builds, without runs or sags, are possible on vertical surfaces using the supercritical fluid spray
process. The higher achievable film builds contribute to the improved appearance in this application,
and, combined with the improved appearance, permit a reduction in number of production steps
necessary.
72
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At another commercial installation of the supercritical fluid spray process, the reformulated
coating has sixty-seven percent less solvent than the conventional formulation applied by air-assisted
airless spray guns. In this application, the supercritical fluid spray process enables the same coating
appearance to be achieved at lower film builds. Overall coating solids usage has been reduced by forty
percent, allowing an overall solvent usage reduction of eighty percent.
COMPARATIVE VOC, COVERAGE, AND COST DATA FOR PLASTIC COATING
Red Spot Paint, a licensee of the supercritical fluid spray process, has developed several
coatings for use with the process. In doing so, it was important for them, and ultimately their
customers, to understand both the technical and economic aspects of the technology. Extensive
comparative data, in terms of VOC, coverage, and cost, has been generated and compiled.
In comparing a conventional automotive-quality exterior acrylic lacquer to the version of the
coating reformulated for use in the supercritical fluid spray process, it was immediately apparent that a
VOC reduction, to the compliant level, was achieved. Michigan Rule 632, the applicable regulation
determining compliance, requires that the coating be applied at less than 5.0 pounds per gallon of
VOC. In addition to the VOC reduction obtained, all of the air toxics, as regulated by the Clean Air
Act, were eliminated from supercritical fluid spray coating formulation.
WEIGHT SOLIDS (supplied)
WEIGHT per GALLON (coating)
VOC (supplied)
SOLVENT REDUCTION
WEIGHT per GALLON (reducer)
VOC (applied)
MI Rule 632 COMPLIANT?
CONVENTIONAL
FORMULATION
25%
7. SO pounds
5.62 Ib/gal
100%
6.68 Ib/gal
6.24 Ib/gal
NO
SUPERCRITICAL FLUID
FORMULATION
36%
7.77 pounds
4.97 Ib/gal
NONE
NONE
4.97 Ib/gal
YES
Initial comparison of the VOC data does not make the supercritical fluid spray formulation
seem too impressive. Relatively, speaking, 4.97 pounds per gallon of VOC does not seem to be a large
improvement over 6.24 pounds per gallon of VOC. However, when the coverages (calculated for 1.0
mil dry film thickness with 100% transfer efficiency) of the two coating formulations are compared, the
advantages of the supercritical fluid spray formulation become much more dramatic.
~~-
VOLUME SOLIDS (supplied)
Theoretical COVERAGE (supplied)
SOLVENT REDUCTION
VOLUME SOLIDS (applied)
Theoretical COVERAGE (applied)
CONVENTIONAL
FORMULATION
18.9%
303 ft2/gal
100%
9.45%
152 ft2/gal
SUPERCRITICAL FLUID
FORMULATION
28.0%
449 ft2/gal
NONE
28.0%
449 ft2/gal
73
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The parameter that stands out the most in the above data is the theoretical coverage data of the
conventional solvent-reduced coating. The applied coverage of the supercritical fluid formulation is
almost three times that of the conventional formulation. The seemingly small difference in the VOC
belies the fact that there is actually a huge difference in the coverages of the two formulations.
While improvements in VOC and coverage are important, it has long been understood that the
best way to improve a paint is to reduce its cost. Without a financial payback, many applicators are
unwilling to implement VOC reducing technologies unless forced to by federal, state, or local,
regulations.
PRICE PER GALLON (coating)
PRICE PER GALLON (reducer)
SOLVENT REDUCTION
'PRICE PER GALLON (CO2)
PRICE PER GALLON (applied)
Theoretical COVERAGE (applied)
COST/FT2 (® 100% Transfer efficiency)
COST/FT2 (9 30% Transfer Efficiency)
CONVENTIONAL
FORMULATION
$18.23
$4.28
100%
NONE
$11.26
152 ft2/gal
$0.074
$0.247
SUPERCRITICAL FLUID
FORMULATION
$26.63
$0.00
NONE
$0.58
$17.21
449 ft2/gal
$0.061
$0.183
* - PRICE PER GALLON (C02) is based on a 30 weight percent reduction of the coating with CO2
with the cost of $0.25/pound of
The significance of the comparative data can be better understood with the realization that the
supercritical fluid spray process has repeated demonstrated superior transfer efficiencies to the air spray
process for which the conventional coating was formulated. It is not unreasonable to expect, in light of
the transfer efficiency studies done, efficiencies in the range of at 50% for the supercritical fluid spray
process. Given that, the economics are even more dramatic.
VOC (applied)
Theoretical COVERAGE (applied)
TRANSFER EFFICIENCY (probable)
COST/FT2
CONVENTIONAL
FORMULATION
6.24 Ib/gal
152 ft2/gal
30%
$0.247 .
SUPERCRITICAL FLUID
FORMULATION
4.97 Ib/gal
449 ft2/gal
50%
$0 122
The data shows that for this particular coating, a mere twenty percent reduction in VOC
realized by utilizing the supercritical fluid spray process translates to a fifty percent reduction in cost
per square foot of coverage for the applied coating. Applying the aforementioned principle regarding
cost reduction and coating improvement - it is clear that the supercritical fluid spray coating is twice as
good as its conventional precursor.
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COATING SYSTEMS
The supercritical fluid spray technology has been used to apply a variety of high-quality clear,
pigmented. and metallic coatings using thermosetting, thermoplastic, air-dry, and two-pack polymer
systems. Polymers that have been successfully demonstrated include acrylics, polyesters, air-dry
alkyds, urethanes, melamines, phenolics, vinyls, epoxies, ureas, nitrocellulose, and cellulose acetate
butyrate. A wide variety of pigments and filler materials have been used, including many colored
organic and inorganic pigments, titanium dioxide, carbon black, aluminum flake, calcium carbonate.
silica, and clay. Most polymers and pigments used in conventional solvent-borne coating systems are
believed to be applicable to the supercritical fluid spray process. For many applications, little or no
adjustment will be needed in the polymer system; only the solvent-blend will need reformulated.
CONCLUSION
Commercial production experience has clearly demonstrated that significant reductions of VOC
emissions can be made in coatings using the supercritical fluid spray process. Contrary to conventional
wisdom, the results also clearly show that, when using the supercritical fluid spray process, these
reductions in pollutant emissions are also characterized by significant improvement in the quality of the
coating and dramatic material and operating cost savings to the coating applicator.
The supercritical fluid spray technology has been shown to be an effective pollution prevention
technology that is applicable to most types of solvent-borne coating systems. Volatile organic
emissions have been reduced up to eighty percent and air toxic solvent emissions have been eliminated
in most coatings reformulated for use with the technology. It is expected that solvent emissions will
continue to be reduced as new coating systems are developed that have improved carbon dioxide
solubility. Eventually, the technology is expected to become the liquid analog to powder coatings but
to have better coating performance and significant application advantages.
Commercial use is expected to continue to expand because the process can be an effective
replacement for conventional high-solids coating applications that use air, HVLP, air-assisted airless,
airless, and rotary spray systems. Besides plastic coating applications, the technology is currently in
place in the market areas of wood furniture, automotive topcoats and components, general industrial,
adhesives, and release coatings. Continued expansion in the existing market segments, and penetration
into the areas of aircraft, metal office furniture, marine, drum, appliance, and specialty applications, is
expected in the near future.
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REFERENCES
1. Johnston, K. Supercritical Fluids. Kirk-Othmcr Encyclopedia of Chemical Technology.
3rd Edition. Supplemental Volume. Wiley-Interscience, New York. 1984.
2. McHugh, M. A. and Krukonis, V. Supercritical Fluid Spray Extraction. Butterworths,
Boston. 1986.
3. Nielsen, K . A. et al. Supercritical Fluid Spray application Technology: A Pollution Prevention
Technology for the Future. Journal of Oil & Color Chemists Association 74(10): 362-368
(October 1991).
4. Nielsen, K. A. et al. Advances in Supercritical Fluid Spray Application of Low-Pollution
Coatings. Presented at the Air & Waste Management Association 84th Annual Meeting &
Exposition. Publication 91-104.5. Vancouver, British Columbia (June. 1991).
5. Anonymous. First Carbon Dioxide Solvent Production System. Industrial Finishing 67(11):
34-36(1991).
6. Nielsen, K. A. et al. A New Atomization Mechanism for Airless Spraying: The Supercritical
Fluid Spray Process. Pages 367-374 in Semerjian, H. G. Editor. Proceedings of the Fifth
International Conference on Liquid Atomization and Spray Systems. NIST Publication 813,
Gaithersburg, Maryland (July 1991).
7. Anonymous. Pennsylvania House Expands UNICARB Use. Industrial Finishing 92(11):
46-49(1991).
8. Nielsen, K. A. et al. Spray Application of Low-VOC Coatings Using Supercritical Fluids.
SAE 1991 Transactions, Journal of Materials & Manufacturing, Sec. 5, Vol. 100: 9-16 (1992).
9. Nielsen, K. A. et al. Supercritical Fluid Spray Coating: Technical Development of a New
Pollution Prevention Technology. Presented at the 20th Water-Borne & Higher-Solids,
and Powder Coating Symposium. New Orleans (February, 1993).
ACKNOWLEDGEMENTS
We acknowledge the valuable contributions of J. N. Argyropolous. R.H. Bailey, D. C. Busby,
R. S. Cesaretti. R. C. Clark, L. J. Craft, D. J. Dickson, R. A. Engleman, C. W. Clancy, J. D. Goad,
B. L. Hilker, K. L. Hoy, A. C. Kuo, J. J. Lear, C. Lee, M. A. Lutterbach, K. M. Perry. M. A.
Perry, N. R. Ramsey, D. C. Ross, G. C. Ross. P. D. Samuel. S. P. Seiler, J. D. Wines, and P. R.
Zitzelsberger. We thank Professor M. D. Donahue of Johns Hopkins University and J. D. Colwell and
Professor D. W. Senser of Purdue University for their assistance.
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(The work described in this abstract was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
(Expanded Abstract; Paper Not Available)
UTILIZING DISPERSION RESINS WITH INORGANIC SOLIDS IN A
NEW FORMULARY BLENDING PROCESS TO ACHIEVE
SYNERGISTIC RESULTS OF PERFORMANCE
Philip W. Coscia
881 Ash Avenue
Gustine, CA 95322
In attempting to assess the dispersion performance of water-borne acrylic, urethane, and vinyl
resins, certain liquid compounds and graded solids regarded commonly as pigments and fillers
were employed. Dispersing these materials without adding to the volatile content, various
surfactant/detergents were used. Microscopic investigation yielded what we considered
unsatisfactory results. As a comparative standard, we then employed textbook formulae in
conjunction with these materials. Investigation of dispersion effectiveness was less complete
than what had been done prior without the use of added volatiles. Because of experience in
other areas of study, it was decided to utilize a blending technique as a developmental
endeavor. It is this method which will be discussed. We have come to realize the far
reaching effect this can have for the asset protection market; complete blending adds to the
life of an applied coating exponentially. There is much to yet be done in this field as the
extensive patentability is still underway and as is the perusal of the technical aspects for the
explanation of the forces at work.
As conventional blending requires the use of additional compounds, which are undesirable as
impactors to the quality of life as air and water contaminators, a blending sequence was
laboratory instituted which demonstrated that highly effective mixing could be achieved in
much less time than required conventionally. Not only was it found that particle size was
reduced without the need for grinding, but compounds could be alloyed that expressed no
affinity for one another. Moreover, minimum amounts of active materials suffice for
performance when functionally dispersed.
Through a hydraulic extrusion in excess of 12,000 psi, a polyether dispersion, in conjunction
with calcium, was driven across an orifice of novel design. This orifice was housed at the
front of a tube which acted as a pressure reducing respository. The construction of the tube
allowed calibration of a harmonic resonance. We found that resonances are particularly
unique to each compound. It was not until explanations for the especially fine compounds
produced defied logic that it was deduced that synergism between the shear at the orifice and
the staged resonance was acting molecularly to set the ingredients at proper limits to their
ionic charges. The visible effects of dispersion and the reduction of particle size achieved a
finished material with exceptional layout and physical performance properties. The time
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savings to produce the finished article appears to be in the range of 60 to 80 percent
Exotherming, common to paint manufacturing and which limits the total blending
completeness of finish, is no longer an issue.
Further calculation relative to orifice/resonance configurations achieved dramatic conclusions.
It was at this time that various compounds, which we knew to be immiscible, were applied to
the process. Alloys were achieved which performed in extended form as their concentrated
counterpart did.
We reviewed the findings of our results and formed conclusions pertinent to physical and
social qualifications:
• Conventional blending by shear blades in open tanks can be replaced by closed
tanks moving materials by centrifugal pump across a shear orifice, reducing
manufacturing air and personnel impact
• Logistics of manufacturing efficiency can be further improved by the
introduction of fluidized ingredients immediately downstream of the orifice.
• A superior finished product with the reudction of undersirable chemicals can be
produced in less time with less energy and manpower.
• Alloys of dissimilar materials known to have no affinity can be produced
which achieve superior performance of asset protection with economy and ease
of application (i.e., hand-rubbed, true perfluorinated wax).
• The where-with-all to realistically bring these findings of fruition for scale
production will require concentrated effort and assets.
• Product yielded by this sequence achieves a balance of components which has
yet to be explained from a molecular standpoint After the initial protections
are in place to allow a request for funds from standard sources, we plan to
develop our discovery further.
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SESSION 3
POWDER COATINGS
PAPERS PRESENTED:
"Advantages of Powder Coating"
by
Albert Holder
Naval Surface Warfare Center
Annapolis, Maryland
"Aerospace Applications for Powder Coating at Hughes Aircraft Company"
by
Larry W. Brown
Hughes Missile Systems Company
Tucson, Arizona
"Fluoropolymer Coatings for Architectural, Automotive & General Industrial Applications"
by
David M. Grafflin
Market Manager - Coatings
Evodex Powder Coatings
Dexter Automotive Materials Division
Birmingham, Alabama
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
ADVANTAGES OF POWDER COATING
ALBERT HOLDER
NAVAL SURFACE WARFARE CENTER
ANNAPOLIS, MARYLAND
ABSTRACT
Powder coating, a curiosity only a short while ago, has
turned, into a 17% per annum growth item in the United States.
How did this happen? The equipment manufacturers improved the
efficiency and equipment was custom made on request, the powder
manufacturers themselves invested in significant research and
development, but it would be fair to say that the EPA
(Environmental Protection Agency) inadvertently did the most to
advance this technology by reducing allowable volatile organic
compound (VOC).
The Federal Government, while slow to change, has invested
substantial time and money, and is using the products. For
example, the Navy coating maintenance facilities on the east and
west coasts are increasing their usage. Why this sudden
interest? One hundred percent solids, no waste on over spray,
dry film thickness from 0.8 mil to 300+ mils, pencil hardness of
6H, are good enough reasons. But most of all, when we recognize
that near zero VOC is definately coming. A survey of the options
indicates that for those components where fusion of the coating
is feasible, powder coating is a good way to go.
INTRODUCTION
Thermoplastic powder coating has been commercially available
since the 50's, but not in a refined form. Particle sizes were
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never consistent, the equipment was adapted to powder coating or
was very expensive. Re-tooling of paint shops was never required
in the budget.
Then in the 60's, thermoset powder coatings came into the
market with better control of particle size. The finished
product looked like liquid paint and in most instances, their
properties were superior.
Still progress was extremely slow in introducing the
technology into paint shops, because of the initial high expense.
There was no necessity to change, as liquid paints were being
made to their specifications or custom made for the old
equipment.
Then came environmental regulations, as administered through
the EPA. The agency's primary function is to control, monitor,
advise and even fine if necessary, any organization or person
violating the federal laws on exceeding the limits for pollution
of the air and water. In our coating industry VOC, toxic
chemicals, and pigments are of concern. As important is the
disposal of waste created during manufacture and application.
Disposal sites are diminishing in numbers, therefore supply and
demand is inflating the cost of disposal. Waste created is the
responsibility of its creator to the very end. With this in mind
management was making an effort to adjust or shutdown. Paints
and coatings with lower VOC's like high solids, waterbased
coatings, and powders were all potential replacements. High
solids and waterbased coatings still produced overspray and
higher loss than powder coating, which has a 96-99% transfer
efficiency. Waste and pollutants are minute in comparison to
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conventional paints.
Equipment manufacturers have done their homework and
introduced new spray guns, spray booths, extruders, mixers, etc.,
by improving efficiency and custom-building of units. Many paint
shops are required at this point in time to replace old
equipment, and those who went with powder are very encouraged.
ECONOMIC ASPECTS
Powder coating is a proven compliance technology, with
negligible overspray loss, no waste, because it can be recycled.
Is it difficult to formulate? No! Liquid coatings can be
much more time consuming, with a great variety of ingredients.
The composition of powder coating versus conventional
paints are compared below:
POWDER COATING LIQUID COATING
PIGMENT(S) PIGMENT(S)
POLYMER(S) POLYMER(S)
CATALYST(S) CATALYST(S)
ADDITIVE(S) ADDITIVES
SOLVENTS
For powder coatings the polymer and catalyst can be
purchased as one resin. Liquid coatings for baking generally
contain more than one polymer, two or more solvents and usually
more than one additive.
MANUFACTURE
POWDER COATING LIQUID COATING
COLLECT INGREDIENTS COLLECT INGREDIENTS
PREMIX DISPERSE
EXTRUDER LET DOWN
CHIPPING ADJUST VISCOSITY
GRINDING PACKAGE
PACKAGE
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Without a doubt, raw material collection for manufacture of
liquid paints or coatings is more labor intensive due to the
greater number of ingredients and the fact that additions can
only be made at certain intervals during manufacture.
APPLICATION
There are two common methods:
FLUIDIZE BED
ELECTROSTATIC SPRAY
TYPES OF RESINS
THERMOPLASTIC
THERMOSET
The thermoset resins or polymers in the future will be used
in place of non-compliance VOC coatings such as epoxy polyamides.
REACTION OF POLYMER TO HEAT
THERMOPLASTIC THERMOSET
MELT MELT
FLOW FLOW
GEL GEL
CURE (NO REMELT)
COMMON THERMOPLASTIC AND THERMOSET POLYMERS
POLYPROPYLENE EPOXY
POLYETHYLENE POLYURETHANE
NYLON ACRYLIC
PVC POLYESTER (LOW MOLECULAR
POLYESTER (HIGH MOLECULAR WEIGHT)
WEIGHT)
Liquid coatings have alkyd resins as the workhorse, powder
coatings have epoxy resins. Epoxies can give thin or thick
films and therefore, can be used for decorative or functional
purposes. They are chemical resistant and FDA approved.
Polyester polymer modified with epoxy resin, polyurethane,
or triglycidyl isocyanurate gives properties not achievable by
the individual polymers.
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Acrylic resins are usually used in combination with blocked
urethanes and have excellent gloss, thin film appearance, and
hardness with only fair impact resistance.
PROPERTIES OF THERMO SET POWDER COATINGS
POLYMER HARDNESS IMPACT SALT-FOG EXTERIOR CUR I
*EPOXY
PENCIL
HB-5H
HB-2H
HB-3H
HB-3H
riNCH-LB)
60-160
60-160
60-160
60-160
( HOURS)
1000
1000
1000
1000
DURABILITY
POOR
FAIR
POOR
GOOD
VERY GOOD
GOOD
GOOD
(DEGREES F7MINS)
450/3
250/30
450/3
325/25
400/7
310/20
400/10
360/25
HYBRID
POLYESTER
ACRYLIC
*Re-bar epoxies are cured 450/25 seconds.
THE ADVANTAGES OF POWDER COATING ARE CONVINCING.
Powder coating shows both technical and economic
advantages in comparison to other processes, while lowering
coating costs, quite considerably, reducing production risks and
are
—economical—thanks to powder recovery
—harmless to the environment—no solvents
—more durable against mechanical influences
—cleaner to work with—no solvents
—easily automated thanks to wrap around
—high build films—achieved in one operation
WHAT ARE THE PROCESS REQUIREMENTS FOR POWDER COATING?
1. Suspension of blank parts
2. Pre-treatment (i.e. de-greasing, phosphating, chromating)
3. Drying
4. Powder coating
5. Baking 275-450 F
6. Removal of cured parts
MARKET SECTORS
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TRANSPORT
-AUTOMOTIVE
-TRUCK & BUS
DOMESTIC
APPLIANCE
BUILDING
ELECTRICAL
GENERAL
INDUSTRIAL
PUBLIC
SERVICE
HEAVY
DUTY
-WHITE GOODS
-HEATING
-FIRES
-LIGHTNING
-ALUMINUM EXTRUSIONS
-CONSTRUCTION PARTS
-STRUCTURAL STEEL/ALUMINUM
-LIGHT/ELECTRONICS
-SWITCHGEAR
-TRADE COATERS
-OFFICE FURNITURE
-BUSINESS MACHINES
-SHELVING AND RACKING
-GARDEN FURNITURE
-STREET LIGHTNING
-FURNITURE
-REBAR
-GENERAL HEAVY DUTY
-PIPELINES
NAVY AND POWDER COATINGS
The Navy has Naval shipyards and Shore Intermediate
Maintenance Activities at various locations on the east and west
coasts that apply powder coatings. In these activities, shops
are set aside for corrosion control and it is here that powder
coatings are being used or seriously considered for production
purposes.
Parts and components are received daily from ships and are
immediately:
—Logged
—Tagged for identification
—Degreased with trisodium phosphate
—Blasted with abrasive, usually aluminum oxide, to near
white metal
—Preheated
—Powder coated 10(+ or - 2) mils thick
—Post heated
B6
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Surface profiles for steel and aluminum are two to three
mils and one to two mils respectively.
Epoxy powder coatings have proved very efficient for Navy
use. The Naval Sea Systems Command (NAVSEA) has designated
powder coatings for shipboard corrosion prevention and control
and is currently conducting testing and evaluation on the
feasibility of using powder coating as sealer and top coating for
thermal spray aluminum. With the longer service life of the
coatings, Naval personnel will have more time for the ship
essentials like training and vital operations.
Powder coatings are less permeable, which is very important
in our case, have short baking times and produce almost no pollutants or
hazards, since no solvents are involved.
Five years of use in corrosion control application has
proved substantially positive. Some of the areas now employing
powder coatings are:
—Vent Screens
—Telephone Boxes
—Electrical Boxes
—Light Fixtures
—Lockers
—Bunk Beds
—Search Light Fixtures
—New Construction
—Battle Helmets
—Or Any Portable Housing
—Valve Bodies
The Navy sees a substantial increase in the use of these
coatings in the never ending battle to prevent or retard
corrosion.
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88
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(The workdescribed in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
AEROSPACE APPLICATIONS for POWDER COATING
at HUGHES AIRCRAFT COMPANY
Larry W. Brown
Hughes Missile Systems Company
P O Box 11337 801 N18
Tucson, AZ. 85734
INTRODUCTION
Regulations restricting Volatile Organic Compound (VOC) emission and hazardous waste
generation and disposal are beginning to seriously impact the painting of aerospace hardware.
Continued use of many of the traditional aerospace paint systems such as the Mil-P-23377 Epoxy
Primer / Mil-C-83286 Urethane Topcoat has been prohibited in many areas of the country since
they exceed 420 gm/liter VOC content Some users of the new compliant paint systems have
experienced significant paint related cost increases due to additional rework, more stringent
record keeping, and increasing hazardous waste disposal costs
Hughes Missile Systems Company (formally the Missile Systems Group of Hughes
Aircraft Company) began working with powder painting in 1983 while searching for improved
painting processes Since the powder painting process produces essentially no VOC's and reduces
hazardous waste generation, it offers significant environmental advantages over competing paint
systems including compliant systems that reduce the level of emissions The Navy approved
powder paint for use on the interior of the Phoenix missile fuselage in 1986 and these have been
successfully powder coated since that date. Additional development work has led to several
more powder paint applications and successful implementations on both the Phoenix and
Maverick missile programs
Organic coatings (paints) serve a wide variety of functions in the missile industry
Exterior surfaces as well as some interior areas of missiles normally receive some type of organic
finish The customer specifies the required finish system based on the requirements of each
service branch or application. The primary function of an organic finish system is for protection
from environmental influences Other associated .functions include visibility characteristics and
missile identification for tactical or training purposes Thus an organic finish system is an
important aspect of missile manufacturing
Conventional liquid paints use solvents to transport the pigments and resins over the
surface to be painted. After the volatiles evaporate, only the pigments and resins that form the
final painted surface remain. Since these volatiles comprise a significant portion (30% to 80%) of
the applied paint film, only a fraction of the applied material forms the dry paint film.
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Powder paint, by comparison, consists of blended resins and pigments ground into a very
fine powder During application this powder is fluidized and usually electro-statically sprayed on
the part being painted The cure process uses an oven at temperatures ranging from 250°F to 400
°F to fuse the paint particles to each other and bond them to the substrate Since there are
essentially no volatile components (significantly less than 1%), all of the applied paint material
becomes pan of the dry paint film
Since the early 1980's powder painting has experienced tremendous growth averaging
almost 20% growth per year in terms of quantities of powder sold1 Powder painting is used in
many commercial applications including appliances, automobiles, office furniture, architectural
applications and sporting equipment. The paint performance requirements for many of these
applications are similar in many respects to the performance required of aerospace coating
systems.
POWDER PAINT MATERIALS
There are two major classifications of powder paint, thermosetting and thermoplastic
Thermosetting powder paints cross-link chemically to produce higher molecular weight materials
during the thermal cure process2 As the material cures, it chemically cross-links and will not
reflow upon re-heating A thermoplastic powder however will melt and flow upon application of
heat, but is chemically unchanged, thus when reheated it will re-flow
Thermoplastic Powder Coatings
Thermoplastic coating materials include polyethylene, polypropylene, nylon,
polyvinylchloride, and thermoplastic polyester Thermoplastic powders are generally used for
special applications requiring thick films and they do not normally compete for the same
applications as liquid paints. The high molecular weight resins used in thermoplastic powder
paints are difficult to grind to the small panicle size necessary for the spray application and fusing
of thin (less than 5 mils) films These coatings are selected for their chemical resistance,
electrical insulation, weather ability, abrasion resistance, or low coefficient of friction
Thermosetting Powder Coatings
Since thermosetting powder paints chemically cross-link during the curing process to form
higher molecular weight products, the cured coating has a different structure and properties than the
basic resin Thermosetting powders can be ground into fine particle (25 - 40 microns average) and
can form thin paint coatings in the 1 to 3 mil range. These powder paints compete for the same
market with available liquid paints since they produce surface coatings with properties equivalent
and sometimes superior to the coatings produced by the liquid compliant technologies A
technological expansion has occurred in the area of thermosetting powder paints in the last few
years The major types of thermosetting powder paints are: epoxy, epoxy polyester hybrid,
urethane polyester, and acrylics
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Epoxy Resin Powders
Epoxy resins are utilized by most thermosetting powder paints in use today. This class
of powders offers excellent chemical resistance, toughness, flexibility, adhesion, and corrosion
characteristics Advances in epoxy formulations have enabled epoxy based powders to be tailored
to a wide range of desired film characteristics Additionally, epoxy powders can be formulated to
cure over a wide range of bake temperatures some with cure temperatures as low as 250° F
Epoxy powders cost less than other available powder formulations
Unfortunately, epoxy powder paints share liquid epoxy paint's limited ultra-violet ( UV )
resistance and thus chalking of the paint surface is the result of extended exterior exposure. An
epoxy powder paint will chalk within a few months of exterior exposure. This chalking does not
significantly affect the paints excellent physical, chemical resistance, or corrosion protection
properties Chalking is a surface phenomena and inhibits further degradation. Cleaning will
restore much of the original paint finish but will allow additional chalking to occur Chalking is
most noticeable on high gloss dark colored paints, while it is least noticeable on light colored low
gloss paints In addition to having equivalent or superior properties, epoxy powders generally
cost less and can be formulated to cure at lower temperatures than other powder materials.
Epoxy Polyester Hybrid Powders
These hybrid coatings were developed in Europe as an attempt to improve the weather
ability of epoxy powders They are closely related to epoxy powders and have similar properties
Hybrid powders have improved over-bake and weather ability characteristics. They still chalk but
the rate of chalking is slower and results in less discoloration than standard epoxy powders
Hybrid powders provide corrosion protection similar to epoxy powders, although they have softer
films and generally demonstrate a reduced resistance to solvents and alkali. These powders have
excellent electrostatic spray characteristics and demonstrate improved penetration into corners
and recesses relative to other powder coatings
Urethnne Polyester Powders
Urethane polyester powders are comparable chemically to the exterior quality urethane
paints which have been used on aircraft, buses, and other vehicles for a number of years. These
films combine toughness with excellent weathering characteristics. These coatings must be
applied in thin films (less than 2 mils) or the mechanical properties, such as impact resistance and
flexibility, tend to be degraded These coatings are good candidates where exterior durability is
required.
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Acrylic Powders
The final group of thermosetting powder coatings is the acrylics, which exhibit excellent
exterior durability. The acrylics generally exhibit excellent hardness and good impact resistance
along with excellent alkali resistance. However, acrylics generally exhibit inferior adhesion
characteristics as compared to other powders Acrylic powders are usually more expensive than
other powder coating formulations
APPLICATION CONSIDERATIONS
Unlike liquid painting technologies, powder painting may not be applicable to every pan
or assembly. Since powder paint is usually applied by electrostatic spraying, the surface being
coated needs to be conductive or have a conductive layer a few mils under the surface. This
conductive layer is grounded during the application process and the charged paint panicles are
electro-statically attracted. A conductive wash may be applied to non-conductive pans, such as
composite materials, to provide a temporary conductive layer sufficient to provide electrostatic
attraction of the paint panicles After the paint particles have been electro-statically applied, the
ground may be removed and the powder panicles will maintain adhesion during normal handling
Powder painted pans or assemblies must be capable of being baked at the powder paint's
cure temperature. Cure temperatures range from about 250°F for a low temperature epoxy
powder paint to over 400°F for some other powder formulations. Although powder cure times
are shon, 5 minutes to approximately 45 minutes, they are at peak temperature, therefore a
massive pan must also be allowed the time necessary to reach temperature in addition to the cure
time. Required cure duration is generally inversely proportional to cure temperature Since
powder paints usually have excellent abrasion resistance, powder painted parts usually require
little or no touch-up after typical assembly processes. These abrasion characteristics allov
components to be powder painted prior to assembly, thus avoiding thermal damage to sensitive
components or assemblies
The pan geometry should also be evaluated to identify areas which may be difficult to
paint due to Faraday cage effect3 These areas can usually be painted successfully, but some
experimenting with application process parameters ( atomizing pressure, powder flow rate,
voltage, etc. ) and spray application geometry may be necessary Some substrate materials or
surface treatments may also require experimentation to insure acceptable paint film characteristics.
Due to the chemical resistance of some powder coatings, they usually cannot be effectively
removed using solvents or paint removers. Removal usually requires some form of media blast to
eliminate the paint economically. Media blast must be carefully evaluated before using it in
applications where non-destructive testing techniques are used, since it may obscure cracks,
corrosion or signs of metal fatigue.
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ECONOMIC CONSIDERATIONS
Powder painting offers several potential economic advantages when compared to liquid
painting technologies4. Savings can be realized in the areas of labor, energy, material, hazardous
waste disposal, and safety. The savings in several of these areas are sometimes difficult to
quantify; however, when analyzed and added together, the powder system usually offers a
significant cost advantage over liquid coating systems. Table 1 summarizes the approximate
costs per square foot for a traditional manual liquid painting operation and a manual powder
painting facility. These costs are very sensitive to part complexity, painted area and lot size and
the data in Table 1 assumes a complex geometry totaling a few square feet of painted area flowing
through the painting operation in lot sizes of approximately 10.
1
I
3 COAT LIQUID
SYSTEMS
LABOR
MATERIAL
ENERGY
WASTE DISPOSAL
TOTAL COST
S/SQUARE
FOOT
2.00
.30
.05
.15
2.50
/
POWDER PAINT
LABOR
MATERIAL
ENERGY
WASTE
DISPOSAL
TOTAL COST
SQUARE FOOT
.50
.15
.05
.05
.75
7
f
Table 1. Cost Comparison - 3 Coat Liquid Paint System vs Powder Paint
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Labor Savings
Labor savings associated with powder painting result from several factors. First, powder
paints are delivered ready to use and require no mixing with solvents or catalysts This eliminates
an entire operation usually associated with liquid coatings Additionally, monitoring and
maintaining many process parameters associated with liquid painting ( viscosity, pH, solvent
content, percent solids, etc. ) is unnecessary. Powder painting is usually a one coat application,
and significant labor savings result from eliminating the application of primer and multiple top
coat applications Powder painting requires less operator skill and training than normally
required for liquid painting Since the powder particles can be removed from the part with
compressed air prior to baking, it is very easy to rework parts prior to cure. After the parts are
cured, any required touch-up can be performed using a compatible liquid paint. Clean-up of the
paint gun and booth is much easier with powder paints and require only a broom and compressed
air, and vacuum cleaner instead of the solvents and wipe cloths required to clean-up after solvent
based liquid painting In some applications powder painting may eliminate up to 75% of the labor
required for liquid painting
Energy
Significant energy savings can be realized from the implementation of powder painting
Since the quantity of volatiles in powder paints are minimal and no room temperature volatiles are
present, the makeup air requirements can be dramatically reduced. No makeup air is required for
the powder paint booth and only small amounts are required to vent the ovens used for curing.
This translates into a significant savings in air conditioning or heating. While the oven
temperatures required for powder painting are significantly higher than normally used to cure
liquid coatings, the cure time is significantly shorter Thus there is usually an energy savings
resulting from implementing powder coating
Material Costs
The increased material utilization advantages possible using powder coatings usually result
in material cost savings when compared to liquid coating systems An electro-statically applied
powder paint will achieve approximately 70 percent first pass material utilization The over-
sprayed powder particles can be collected, screened and then mixed with virgin powder for reuse
Since less than 1 percent of the applied material" is volatile, powders easily achieve material
utilization rates of about 95 percent Liquid systems usually achieve overall material utilization
rates of between 20 to 60 percent since the over-spray cannot be recycled and the sprayed
material contains large quantities of volatiles
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There are fewer materials to store since powder coatings usually replace both the primer
and topcoat Most powder paints can be stored in room temperature environments (65° to 85°
F, < 50% Relative Humidity) however low temperature cure powders (< 300 ° F) may require
refrigerated conditions Shelf life for properly stored material may vary from 6 to 12 months for
low temperature powders to several years for other formulations
Since drips and runs are almost nonexistent with powder painting, the reject rate typically
declines, resulting in higher yields. The cured powder paint film usually has better abrasion
characteristics than liquid paints. This enables powder painted pans to withstand handling and
assembly with less paint damage, thus resulting in reduced rework. Additionally, cleanup of spray
guns and paint booths used for powder painting requires no solvents and is therefore safer,
cheaper and easier.
Environmental Costs
Significant quantities of flammable hazardous materials, including cleaning solvents, mixed
paint, catalysts, etc., are associated with liquid painting systems These require special handling,
storage, and disposal. The need for these solvents and other flammable hazardous materials is
eliminated when using powder coatings. The quantity and type of hazardous waste generated
from a powder coating operation is dependent on the type of powder, resin formulation and
pigmentation (metallic) constituents Powder paint formulation sources indicate that modern
powder paints should pass the Toxicity Characteristic Leaching Procedure (TCLP) testing and
alternatives to disposal as hazardous waste of excess or used powder may be available depending
on local regulations. Therefore, to ensure proper disposal, the waste classification or listing
should be determined on a case by case basis. Powders have several environmental advantages
when compared to solvent based liquid coating systems. These advantages, including greatly
reduced solvent use, lower fire hazard, and greater operator safety, provide a cost advantage
when comparing powder painting to other painting systems. The cost and liability associated with
waste generated from a powder coating process may be considerably less than a solvent base
painting system.
In many areas, the use of certain liquid coatings is either prohibited or requires the
installation and operation of expensive adsorption devices to remove VOCs from paint booth and
oven exhausts The lack of volatiles in powder paints eliminates this problem and may
significantly reduce the fire risk Powder paints also result in a much cleaner environment for
paint shop employees, and may lower labor costs by reducing the overhead associated with safety
equipment and allowing a lower job class employee to perform the task.
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HUGHES MISSILE SYSTEMS COMPANY (IIMSQ
The standard liquid paint system used at the HMSC Tucson plant site is the Mil-P-23377
epoxy primer and the Mil-C-83286 Urethane topcoat. A Mil-C-8514 wash primer is also used
on some alloys including inconnel. Prior to 1986 ail production hardware was painted using
these or similar high-solvent liquid paints. HMSC began evaluating powder paint in 1983 and
implemented several epoxy powder painting applications on both the Phoenix and Maverick
missile systems between 1986 and January 1991. These powder paint applications accounted for
approximately 60% of the facilities production painting volume after January 1991.
The typical conventional wet paint process flow chart is presented in Figure 1 with all
VOC emission points and hazardous material generation points are identified. On substrates
where a wash primer is required several additional operations are required which add additional
VOC emission points and hazardous waste generation points to the flow chart. Thus our
conventional painting process consists of at least thirteen operations, twelve of which produce
VOC emissions and eight of which produce hazardous waste.
F.I THIRTEEN STEPS
| | TWELVE VCX; EMISSION ACTIVITIES
HI EIGHT HAZMAT (PAINT, PAINT COMPONENTS. AND SOLVENTS) GENERATION ACTIVITIES
Figure 1: Typical Liquid Paint System Process Flow
Figure 2 shows the epoxy powder painting process which has been used to replace
conventional wet painting on several applications at the HMSC Tucson facility. This process
consists of only six operations with only one VOC emission point, one hazardous material
generation operation and two possible hazardous material (HAZMAT) generation operations.
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f~%
HAZMAT?
SIX STEPS
1 VOC EMISSION ACTIVITY
1 HAZMAT GENERATION ACTIVITY
2 POSSIBLE HAZMAT GENERATION ACTIVITIES
Figure 2: Powder Paint Process Flow
The Toxicity Characteristic Leaching Procedure (TCLP) test data for the powder we use
indicates that it can be disposed of as ordinary waste instead of hazardous waste however this
needs to be evaluated for each powder paint and regulatory environment. Thus the only VOC and
HAZMAT generation point is the cleaning operation prior to painting. By implementing a high
pressure aqueous cleaning system this VOC and HAZMAT generation point was eliminated for
the powder painting of the Maverick airframe resulting in a paint process with no VOC emissions
or hazardous material generation points.
Comprehensive testing has been required to qualify powder paint for all current
applications since no Military Specifications cover the application or material performance of
powder paint on airborne systems. A portion of the many tests procedures included salt fog,
humidity, dry and wet tape adhesion, abrasion resistance, impact, and resistance to various
solvents. The selected epoxy powder paint system was typically equivalent or superior to the Mil-
P-23377 / Mil-C-83286 paint system which was used as the benchmark. Since no appropriate
powder paint Mil-Specs exist, internal specification control drawings are developed and
engineering changes specifying powder painting are processed and evaluated on a case by case
basis. Although this is a lengthy process, environmental and cost benefits following
implementation make the effort worthwhile.
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POWDER COATING INDUSTRY
Powder painting systems suitable for most applications are currently available from several
suppliers. Most low and medium volume applications can be handled using booths with manual
electrostatic powder application guns and no powder re-claim capability5 For most applications
these systems would use existing batch ovens for curing and could be integrated into existing
paint shops Systems for high volume applications is considerably more expensive since they
usually incorporate capability for quick color change, powder re-claim, and monorail conveyor
systems feeding the pre-treatment equipment, powder paint booth, and cure oven.
There are over ten major powder paint manufacturers supplying the US market While
most of these have worked with the aerospace industry they primarily supply powders for the
automotive, appliance, and industrial markets. AJ1 of these manufacturers have powder
development laboratories and can formulate small quantities of custom powders for testing.
Minimum lot size for custom formulations may range from about 250 to 1500 pounds
Purchasing small quantities of custom powders for low rate applications can be challenging
although the situation seems to be improving and one powder manufacturer is specifically
targeting aerospace applications. Another powder manufacturer has recently added the capability
to supply from stock the full range of Fed Std 595a colors in a polyester powder formulation.
Powder Paint Specifications
The only Military Specification for powder painting is Mil-C-24712 "Coatings, Powdered
Epoxy" issued by the Naval Sea Systems Command in February 1989. This specification was
intended for interior steel and aluminum equipment, furniture, electrical box surfaces and exterior
steel and aluminum surfaces exposed to marine environments. The first revision of this
specification is scheduled to be issued in the near future and will add polyester powder paints for
improved exterior UV resistance Paints meeting Mil-C-24712 are available from several sources.
Other specifications such as WS 22351 for the Mark 48 torpedo cover powder painting
for specific weapon systems This particular specification was issued by the Naval Underwater
Systems Center and covers the powder materials, application processes and test requirements for
the ADCAP torpedo.
CONCLUSIONS
Experience at the HMSC Tucson plant site has demonstrated that powder painting
consistently reduces the cost associated with painting while essentially eliminating paint related
VOC emissions and HAZMAT generation. Although powder painting is not currently suitable
for all aerospace applications it is both cost effective and appropriate for many applications
Increasingly stringent environmental regulations tend to favor the long term development and
implementation of powder painting since it eliminates both VOC emissions and hazardous waste
generation
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The cost savings and quality improvements associated with powder painting has enabled
HMSC to be proactive in developing and implementing this environmentally friendly process even
in today's competitive environment Efforts to implement new powder paint applications at
HMSC are expected to continue especially since previous powder painting applications have
demonstrated cost reductions, quality improvements in addition to eliminating paint related VOC
emissions and hazardous waste generation
REFERENCES
1 Bocchi, G J Powder Coatings A World Market Overview, Conference Proceedings,
Powder Coating'88, Sponsored by the Powder Coating Institute. Nov 1-3, 1988 p 1-3
2 Hester, Charles I , Nicholson, Rebecca L. "Powder Coatings Technology Update",
Environmetnal Protection Agency, Control Technology Center, EPA-450/3-89-33,
October 1989, p 5-10.
3 Lehr, William D Powder Coating Systems, McGraw-Hill, Inc 1991, p 104-106
4 Miller, Emery ed. User's Guide to Powder Coating, 2nd edition, SME, 1987, p. 21-28.
5 Serio, Earl, Powder Coating Application Equipment for the Small End User, Conference
Proceedings, Powder Coating '92. Sponsored by the Powder Coating Institute,
Oct 6-8, 1992, p 207-220
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100
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
FLUOROPOLYMER COATINGS FOR
ARCHITECTURAL, AUTOMOTIVE & GENERAL
INDUSTRIAL APPLICATIONS
David M. Grafflin
Market Manager - Coatings
Dexter Automotive Materials Division
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The primary focus of this paper is an exciting, environmentally-compliant
full-strength fluoropolymer powder coatings technology which combines all of the
traditional performance of the low solids solvent-borne PVDF (polyvinylidene
difluoride) coatings used primarily in exterior architectural applications and
specialty automotive critical fluids tubing requirements in a 100% solids powder
coating system. The development of a commercially viable PVDF powder coating for
these applications is the direct result of successfully addressing the somewhat
unique issues relating to the efficient processing of the raw materials, rather
than a modification of the basic chemistry which has been utilized in a liquid,
solvent-borne format since the mid-1960's. The high level of performance which
this chemistry has demonstrated in terms of the recognized aggressive architec-
tural specifications and its resistance to ultraviolet light degradation,
chemical and mechanical attack and automotive fluid resistance requirements, was
initially evaluated with great care to determine the percentage of the weight
solids of the formulation which needed to be composed of the PVDF component. In
an evaluation array which spanned PVDF composition at everything from ten percent
(by weight solids) to ninety percent of the formulation, with a variety of co-
polymer chemistries as the associated vehicle, it was convincingly demonstrated
that the PVDF material (effectively dispersed in a solvent vehicle) at a fifty
percent level, began to have a positive impact on the performance of the applied
film, and that at a seventy percent level, the optimum balance of performance and
ease of application was accomplished, and this quickly became the standard of the
industry.
At the time that this technology was commercially introduced in its liquid
form (through a series of coatings companies who were licensed to utilize the
PVDF resin in this marketplace), the fact that this chemistry was self-limited
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to a maximum of 35% volume solids, by virtue of the difficulties in dispersing
the resin, was a non-issue, as the entire discussion of VOCs and their
environmental impact had not surfaced. During the decade of the 1970's and into
the early 1980's, the effectiveness of this solvent-borne liquid chemistry
continued and flourished, and there were very few efforts directed at moving
toward a compliant vehicle. The work which was done was directed initially at
a water-borne dispersion of the resin, which proved extremely difficult and
ineffective in sprayable formulations, resulting in films which demonstrated
inconsistent performance, and which were more difficult to apply due to a
tendency of the resin to agglomerate within the coating itself. At the same
time, in those applications which were being performed on conventional coil
coating lines (the high volume users of this chemistry), the installation of
incinerators during the early energy crisis to capture the relatively high
solvent levels in these formulations in order to recover the fuel potential in
these low volume solids formulations further reduced the interest in a move to
compliant chemistries. The remaining segment of the market which was going to
have to address this problem was in the spray application end, typically handled
by entrepreneurial independent applicators who were, at least at that time, not
getting extensive attention from the regulatory agencies.
Against this backdrop of a protected channel of distribution and the
limited scope of enforcement activity, there was no driving compulsion for the
primary resin suppliers to develop a compliant material. In the automotive
tubing market, virtually all of the initial applications for this technology were
developed and utilized in Japan with no associated environmental pressure to
bring these materials into compliance. The applications were primarily via dip
application and were able to coat relatively large quantities of tubing with
fairly small quantities of coating which further reduced the visibility of the
process as a source of potential environmental liabilities.
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In the American architectural metals marketplace, essentially none of the
applicators were involved in or particularly aware of powder coatings as a
technology, nor were they equipped to apply the material. In Europe, however,
the situation was functionally quite different. The architectural marketplace
was successfully being supplied with polyester powder coatings, both due to the
lower levels of UV exposure present in their environment, and the significantly
different infra-structure which had never fostered the growth of a viable PVDF
liquid coatings market. The applicators and the coatings manufacturers supplying
this market were very comfortable with powder coatings as a technology, and with
the somewhat different cosmetic appearance which powder coatings provide (the
slight "orange peel" evident in the cured film). For them, the question was
whether or not they needed a PVDF powder coating product, as they had never seen
their market significantly impacted by the liquid material, nor were their
customers demanding a significant upgrade in product quality. The marketplace
had grown accustomed to the solid but reduced performance of polyester films when
compared to full-strength PVDF films, and they were already environmentally
compliant by virtue of functioning in a powder system. They certainly had no
desire to make a move to PVDF in any liquid format, either solvent or water
borne, as this would be a complete transition in their coatings lines, and their
potential interest in a PVDF powder coating was driven by the desire to be able
to compete in an increasing global market with a product which met the
requirements of the two most environmentally aggressive and growing markets,
North America and the Pacific Rim.
It is worth noting that the bulk of the European higher quality
requirements were initially being met with TGIC polyester powder coatings. The
TGIC crosslinker (triglyceridyl isocyanurate) has become the subject of much
discussion in the past two years concerning its potential as a mutagen, based on
both inhalation and ingest ion studies in Europe and the United States. After
extensive testing and great public debate which was leading the coating suppliers
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to evaluate and to commercialize non-TGIC polyester systems, a re-evaluation of
the test data has led to a minimization of the concerns, and in fact, in many
markets, the pressure has essentially disappeared concerning the elimination of
this material. The alternative crosslinkers which have been evaluated are
competitive in performance at essentially equivalent cost, but given the lack of
extended exposure and test data with them in formulated coatings, there has been
reluctance to move forward with a wholesale change given the reduced pressure
from a hazardous materials perspective.
Sigma Coatings, B.V., in the Netherlands, who had significant commercial
activity in PVDF liquid coil coatings and polyester powder coatings for the
architectural marketplace, became seriously interested in the potential for a
PVDF powder coating in the early 1980's, and undertook a research project in
their facility in Zeist which quickly arrived at the same functional hurdle which
the preliminary efforts in the USA had identified in similar attempts earlier -
the complexity of this issue was not in its chemistry (the formulas of the two
versions of this technology are identical), but in the efficient processing of
this material, given the thermoplastic nature of the resin, in order to make its
application economical, and competitive to the liquid formulations well-
established in the marketplace.
Traditional thermosetting powder coatings are manufactured in a dry
blending process in which the ingredients are measured, and blended together
prior to being introduced into a modestly heated extruder from which they emerge
in a viscous condition, are rolled out into a ribbon which is cooled and cracked
into chips or flakes, and subsequently introduced into a conventional grinder
which reduces the material to the fine particle size distribution which is
typical of powder coatings. If this same procedure is utilized with PVDF
chemistries, their thermoplastic nature survives in traditional processing up
until the material emerges from the extruder. At that point, the material is
thoroughly incompatible with room temperature grinding as it rapidly melts into
a taffy-like mass which resists further processing.
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The technical approach taken by Sigma Coatings was directed at simplifying
the processing of this material in light of its thermoplasticity, and toward
developing a mechanical sequence which resulted in a high percentage through-put
of a viable material. The first significant change came at the exit of the
extruder, where rather than extruding the blended powder coating out through
chilled rolls in a ribbon-like format, the extrudate is forced through a water-
chilled die so that it resembles uncooked spaghetti strands which can then be
chopped into small semi-rigid pellets for further processing.
After a series of empirical evaluations, it was rapidly determined that
conventional water cooling was not sufficient for effective processing of this
material into a usable product, and work was begun on identifying the most
appropriate cryogenic temperatures at which a workable material could be
manufactured. The results of this work (now well-documented in two US patents
issued in 1986 and 1989) demonstrated that pre-cooling the pellets produced in
the extruder by immersion in liquid nitrogen at approximately -50°C., and
introducing them into a grinder charged with liquid nitrogen at a volume which
maintains the pellets at approximately -125CC. throughout the grinding process,
yielding in excess of ninety-seven percent usable product. The powder which is
produced is predominantly in the 40-55 micron particle size distribution range,
and once applied, demonstrates superior film flow and leveling, resulting in a
cosmetically attractive film which provides all of the performance of the
traditional solvent-borne materials, and reduces their approximately 6.5 pounds
per gallon of VOC's to almost nothing. In addition, by the nature of the
chemistry, the finished PVDF powder coating is extremely compatible with
electrostatic application (either corona or tribo), and applies effectively at
extremely low voltage and air settings on any available powder coating equipment.
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No conversion of technology euch as this happens easily, or with direct
translation of all of the benefits of the former system into the new one. Powder
coatings, by virtue of their composition and format, will never be able to
replicate the blending systems readily available in their liquid counterparts
which make possible the combination of base colors into custom colors in very
small batches. In addition, the liquid clear coats which are produced in liquid
fluoropolymer chemistry as an adjunct coating to the color coats are not possible
in powder, as the exposure to liquid nitrogen hazes the material irreversibly and
imparts a cloudiness to the applied film which is cosmetically and functionally
unacceptable. In addition, it is more difficult to produce brilliant metallic
colors in this technology through the typical powder coating bonding process as
it tends to fuse the thermoplastic material unacceptably, while dry-blended PVDF
metallics are certainly viable. Beyond these few limitations, it is important
to repeat that the color space of PVDF coatings, either powder or liquid, is
EXACTLY the same by virtue of the fact that the pigmentation utilized to deliver
the performance mandated by the architectural specifications which typically call
for this material (American Architectural Manufacturers Association 605.2, etc.)
is identical. These ceramic pigments, which demonstrate tremendous stability in
extended UV exposure, and deliver the high levels of color and gloss retention
demonstrated by PVDF films, are identical in the liquid and powder formulations,
assuring that the colors are the same in the final films. The resin which is the
backbone of these PVDF coatings, traditionally known by the tradename of its
producer (Kynar 500* as produced originally by the Pennwalt Corporation, more
recently acquired by Elf Atochem North America, Inc.), is different in its
particle size depending on whether the vehicle is to be powder or liquid. Kynar
500*, when provided for powder coating use, is provided in a finer particle size
under the tradename Kynar 500PC*. The chemical composition of the resin is un-
changed, as is the performance of the applied film, as measured in all of the
traditional measures of architectural performance.
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The longest term measure of performance, and the single criterion which
most specifically separates full-strength PVDF films from their lesser
counterparts, is the stability of these coatings in extended exterior exposure.
The traditional measurement in the architectural market is color and gloss
retention after five years of exposure in South Florida at a 45° angle. The
first panels of liquid PVDF films went on exposure in early 1964, and there are
literally thousands and thousands of such panels still on exposure, amply
demonstrating the performance properties of this material. The first panels of
powder PVDF films went on similar exposure in April of 1986, and as of this
meeting are now over seven years old, and are demonstrating all of the
performance characteristics of their liquid counterparts in terms of exposure.
In accelerated testing, the powder films meet and exceed all of the physical
testing standards, with the superior performance most associated with the fact
that the powder coatings tend to develop a thicker film than their liquid
counterparts (1.6-1.8 mils total film versus 1.0-1.2 mils total film), with the
advantages seen most often in falling sand resistance, transit abrasion and
handling damage improvement, preferable pencil hardness, and more uniform
deposition on formed radii and shapes.
The thermoplastic systems described in this paper are applied as the last
step of a total finishing process for architectural substrates. From the
pretreatment perspective, the requirements for proper cleaning and either
chromate or chrome-phosphate conversion coatings, remain the same in powder as
they are in liquid. There is a requirement for a traditional primer chemistry,
available in either a liquid flash version or a powder cured vehicle, under the
PVDF powder coatings. The specific gravity of the PVDF powder coatings is
relatively high, typically 1.7, which sees applications efficiencies on line with
proper voltage and air controls, at the level of 60 square feet of coverage per
pound of powder applied or more, with extremely high first pass transfer
efficiency given the electrostatic affinity of this material to which we have
already referred.
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With the demonstration of a viable thermoplastic PVDF powder coating for
monumental architectural applications, the industry now has a full range of
environmentally compliant technologies with which to address the emerging
enforcement of the 1990 Clean Air Act and its amendments. From the conventional
TGIC polyesters on which this market segment was founded in Europe, to the
emergence of the functionally equivalent non-TGIC polyesters which resolve the
potential for any mutagenic concerns during application, to the presence of the
PVDF films, there is now a range of product qualities available which meet and
exceed the requirements for commercial/light industrial/low-rise architectural
specifications (AAHA 603.8 typically), right through monumental architectural
specifications as discussed (AAMA 605.2 typically). It is worth re-stating that
the performance of these materials and the differences between them is the same
in powder as it is in liquid, as the chemistries neither gain nor lose properties
by virtue of their physical state. The greatest differences in gloss and color
retention between polyesters and f luoropolymers relate both to the base resin and
the pigmentation (polyester versus PVDF and organic versus ceramic), and in a
study which spans a wide color space, with both systems formulated to the same
colors at roughly equal low gloss levels, performance in 45° South Florida
exposure is as follows:
RETAINED
ORIGINAL GLOSS
COLOR RESIN SYSTEM GLOSS (3 YEARS) AE
White Polyester 30.0 11.7 1.60
White Kynar 500* PVDF 37.0 44.7 1.09
Yellow Polyester 28.0 9.2 15.43
Yellow Kynar 500* PVDF 15.0 20.7 3.06
Dark Blue Polyester 29.0 2.7 9.48
Dark Blue Kynar 500* PVDF 4.0 5.5 1.20
Black Polyester 32.0 2.8 10.30
Black Kynar 500* PVDF 17.0 16.9 1.26
Dark Brown Polyester 38.0 1.7 11.52
Dark Brown Kynar 500* PVDF 43.0 39.5 1.14
The two systems utilized to perform this study are currently commercial
systems which are in wide distribution for architectural applications of the
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typical variety (everything from window systems to entryways to spandrel panels
to full curtain-wall configurations). rive year exposures in Florida in full
strength fluoropolymer powder and liquid systems are virtually indistinguishable
in their performance against the requirements for color stability, gloss
retention, film integrity and other barometers of performance. In the automotive
marketplace, interest has now expanded from the critical fluids tubing
application to utilizing PVDF cabling compounds for fuel hoses (both in vehicle
and in fuel pumping applications) and to the use of PVDF films for fuel tank
lining applications and for body-color-matched side molding applications where
the exceptionally strong weathering resistance can support the cost of a more
expensive material. There are numerous evaluations underway at the domestic Big
Three and the transplants to expand the use of this technology in its more
compliant forms (film, powder, water-borne, etc.) as well as in the traditional
solvent systems, with the obvious advantages for environmental compliance
favoring the non-solvent borne materials.
Before closing, it is appropriate to review other characteristics of
f luoropolymer powder coatings technologies which must be kept in mind during its
application. As with other powder coatings, this material is melt-processable,
and recommended peak metal temperatures must be reached in order to achieve full
"cure" of the applied film. The recommended time at temperature is the same as
it is for its liquid counterpart (5 minutes above 450°F.). In order to optimize
the flow and leveling of the topcoat, the powder primer must be at least
partially cured prior to application of the topcoat. This preliminary cure also
serves to assure that there will be none of the powder primer which is knocked
down into the reclaim of the topcoat, thereby diminishing its integrity. The
liquid flash primer requires a minimum of 5 minutes of flash time prior to
application of the topcoat to assure that all residual solvents are removed from
the primer film and do not blow through the topcoat during the curing cycle. In
addition, the liquid flash primer is formulated without the traditional strontium
chromate component, making it the most environmentally compliant liquid material
currently available.
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In the other segments of this conference, many other aspect* of the
handling and application of thermoplastic powder coatings have been covered. For
both the automotive and architectural communities which are still coming to grips
with this technology, the opportunity this material presents to set aside all of
the potential environmental complications which the traditional technology
entails (the need to incinerate at considerable expense, and the calculated risk
of chasing federal and local air quality regulations which will be ratcheted down
in increments over the next several years during the enforcement of the Clean Air
Act) is significant. Given the extremely high level of vocs existing in the
traditional formulations (higher on a per unit basis than almost any other
conventional coating), the liquid fluoropolymer coatings will be among the first
to be targeted by the probable increase in regulatory enforcement over the next
few months and years. The availability of a proven technology in a fully
compliant form which exceeds the demands and expectations of the material
specifiers, the regulators, and the architectural and automotive customers is a
tribute to those who had the foresight to tackle the unique processing
characteristics of a performance-capable thermoplastic material, and to develop
the appropriate procedures to make it viable.
David M. Grafflin
Market Manager - Coatings
DEXTER AUTOMOTIVE MATERIALS DIV.
psb/5-6-93
NOTE: Kynar 500* and Kynar 500PC* are registered trademarks of Elf
Atochem North America, Inc. (formerly the Pennwalt
Corporation), for their architectural f luoropolymer resins.
Ill
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BIOGRAPHY
DAVID N. GRAFFLIN
MARKET MANAGER - COATINGS
THE DEXTER CORPORATION
DEXTER AUTOMOTIVE MATERIALS DIVISION
1-7 EAST WATER STREET
WAUKEGAN, IL 60085
Currently serving as Market Manager-Coatings for the Coatings Group of Dexter
Automotive Materials Division, encompassing the activities of EVODEX Powder
Coatings (a joint venture of The Dexter Corporation and Evode Group pic), Mr.
Grafflin has spent the last eight years in domestic and international market
development of a variety of fluoropolymer technologies, with a particular
emphasis in full strength PVDF powder coatings.
Since the commercial introduction of this material in the North American market
in 1991 (when it reached five years Florida exposure), EVODEX has provided a full
spectrum of powder coatings for interior and exterior residential, commercial,
industrial and monumental architectural applications.
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SESSION 4
FEDERAL PROGRAMS
PAPERS PRESENTED:
"U.S. Navy Compliance to Shipbuilding and Ship Repair Environmental Regulations"
by
Alex Kaznoff
Naval Sea Systems Command
Arlington, Virginia
"Low-VOC Coatings Developed by DOE for Environmentally Conscious Manufacturers"
by
Mark D. Smith
Allied Signal, Inc.
Kansas City, Missouri
The Precedent-Setting Use of a Pollution Prevention Project in an EPA
Enforcement Settlement: The First Dollar-for-Dollar Penalty Offset"
by
David Nelson
EnviroSearch International
Salt Lake City, Utah
and
James J. Periconi
Donovan Leisure Newton & Irvine
New York, New York
"Array Pollution Prevention Success Stories"
by
Jack Hurd
Army Acquisition Pollution Prevention Support Office
Alexandria, Virginia
and
Mark W. Ingle
Ocean City Research Corporation
Arlington, Virginia
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be Inferred.)
US NAVY COMPLIANCE TO SHIPBUILDING AND SHIP REPAIR
ENVIRONMENTAL REGULATIONS
NAVAL SEA SYSTEMS COMMAND
CODE05M
ALEXKAZNOFF
-------
OVERVIEW
O CLEAN AIR ACT AMENDMENT (CAAA)
O CONTROL TECHNIQUES GUIDELINES (CTG)
O NATIONAL EMISSION STANDARD FOR HAZARDOUS AIR POLLUTANTS
(NESHAP)
O CALIFORNIA REGULATIONS
O CURRENT DoD COMPLIANCE EFFORTS
i
O DoD TR1-SERVICE RAD COATINGS PROGRAMS
DUMB
-------
CLEAN AIR ACT AMENDMENT
-------
CAAA TTTUES 1 & 3
O MAAQS (TITUE 1)
o OZONE: ESTABLISH AND ISSUE COMT1ROL TECHNIQUES GUIDEUNES
(CTGs) TO REDUCE AGGREGATE EMISSIONS OF VOLATILE
ORGANIC COMPOUNDS (VOCs)
> > VOCs: MANY SOLVENTS USED IN PAINTS CHEMICALLY REACT
WITH NQx AND SUNLIGHT IN THE ATMOSPHERE TO
FORM OZONE
o PM-10: ESTABLISH AND ISSUE CONTROL TECHNIQUES GUIDELINES
« (CTGs) TO REDUCE AGGREGATE EMISSIONS OF PM-10
» PM-10; PART1CULATE MATTER WITH A DIAMETER OF LESS
THAN OR EQUAL TO TEN MICRONS
O HAPs(TITLE3)
o HAPs: ESTABLISH AND ISSUE NATIONAL EMISSION STANDARD FOR
HAZARDOUS AIR POLLUTANTS (NESHAP)
> > HAPs: HAZARDOUS AIR POLUJTANTS WHICH POSE ADVERSE
ENVIRONMENTAL AND/OR HUMAN HEALTH AND SAFETY
EFFECTS (APPROX.189 HAPs)
DM. MB
BIMTM
-------
CONTROL TECHNIQUES GUIDEUNES (CTGs) FOR VOC SOURCES
O FEDERAL OZONE MEASURES (CAAA - TITLE I)
o ISSUE CTGs FOR STATIONARY SOURCES OF VOC EMISSIONS FROM
PAINTING IN THE FOLLOWING INDUSTRIES:
AUTOMOBILE/LJGHT TRUCK - METAL FURNITURE
METAL COO. • LARGE APPLIANCES
FABRICS - PAPER
MAGNETIC WIRE INSULATION - CANS
MISCELLANEOUS METAL PARTS - FLATWOOD PANNELJNG
- AEROSPACE
* SHIPBUILDING OPERATIONS AND SHIP REPAIR COATINGS AND
SOLVENTS- COVERS VOC AND PM-10 EMISSIONS
O HAZARDOUS AIR POLLUTANTS (CAAA - TITLE 3)
o ISSUE NESHAPs FOR ALL STATIONARY SOURCES THAT EMITS HAPs
OR.MEXRUMUV
-------
SHIPBUILDING OPERATIONS AND SHIP REPAIR CTG
FEDERAL REGULATORY DEADLINES
ISSUANCE: BEFORE NOVEMBER 15,1993
EFFEC7TVTTY: TO BE DETERMINED, FED & STATE IMPLEMENTATION
MAY BE DIFFERENT
IMPACTS
o EXISTING SHIPBUILDING AND SHIP REPAIR EMISSIONS SOURCES IN
NONATTAINMENT AREAS
O VOC AND PM-10 EMISSIONS FROM THE APPLICATION AND REMOVAL OF
PAINTS, COATINGS, AND SOLVENTS ABOARD MARINE VESSELS (EXCLUDING
PLEASURE CRAFT)
o VOC AND PM-10 OMISSIONS STANDARDS BASED ON BEST AVAILABLE
CONTROL MEASURES (BACM)
BACM: AN EMISSION LIMITATION THAT WILL ACHIEVE THE LOWEST
ACHIEVEABLE EMISSION RATE FOR THE SOURCE TO WHICH
HT IS APPLIED
CODECOM
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SHIPBUILDING OPERATIONS AND SHIP REPAIR NESHAP
O FEDERAL REGULATORY DEADUNES - NESHAP
ISSUANCE: NOVEMBER 15,1993 (ORG. NOV *94)
EFFECnVfTY: TO BE DETERMINED
O IMPACTS
O NEW AND EXISTING SHIPBUILDING AND SHIP REPAIR FACILITIES
CONSIDERED MAJOR AND AREA EMISSIONS SOURCES (189 HAPs)
MAJOR SOURCE: 10 TONS/YR OR MORE OF ANY HAP OR 25 TONS/YR
OR MORE OF ANY COMBINATION OF HAPs
O PHASE I - DEVELOP HAPs EMISSIONS STANDARDS BASED ON MAXIMUM
ACHIEVEABLE CONTROL TECHNOLOGY (MACT)
MACT: NEW- AS STRINGENT AS THE AVG. ACHIEVED BY THE
BEST CONTROLLED SIMILAR SOURCE
EXISTING - AS STRINGENT AS THE AVG. ACHIEVED BY
THE BEST 12 PERCENT OF EXISTING
SOURCES
o PHASE II - DEVELOP RISK-BASED EMISSION REDUCTIONS
-------
STATE REGULATIONS
O STATES REQUIRED TO DEVELOP •STATE IMPLEMENTATION PLAN' (SIP) WHICH
ADOPTS FEDERALRECHJIREMaiTSASAMINlMUM TO ACHIEVEMENT ATTAINMENT
OFCAA
o CALIFORNIA
14 AIR QUALITY MANAGEMBTT DISTRICTS (AQMDs)
-BAY AREA AQMD
.SOUTH COAST AQMD
-SAN DIEGO APCD
O CALIFORNIA REGULATIONS IMPACTING DoD ACTWITTES
o ARCHITECTURAL & INDUSTRIAL MAINTENANCE (AIM) REGULATIONS
PAINTS APPLIED TO SHOREBASED FACILITY STRUCTURES
o MISCELLANEOUS METAL PARTS AND PRODUCTS
PAINTS APPLIED TO SMALL METAL PARTS (USUAULY LIMITED TO SHOP
APPLICATIONS
•IMYB
-------
U)
CALIFORNIA REGULATIONS IMPACTING DoD ACTIVITIES (cont'd)
o AEROSPACE COATINGS
PAINTS APPLIED TO AIRCRAFT OR EQUIPMENT/ORDNANCE INSTALLED
ON AIRCRAFT
o MARINE COATINGS
PAINTS APPLIED TO MARINE VESSELS OR EQUIPMENT/ORDNANCE
INSTALLED ABOARD MARINE VESSELS
CALIFORNIA REGULATION REQUIREMENTS
o GENERAL LIMITS FOR VOC CONTENT
AIR DRIED COATINGS (CURE AT TEMPERATURES BELOW 194T)
BAKED COATINGS (CURE AT TEMPERATURES ABOVE 194T)
o SPECIALCOAT1NGAPPLICAT1ONIJMITSFORVOCCONTENT(ESSEiniALFOR
CONTINUED MARINE COATINGS OPERATIONS
VOC CONTENT LIMITS BASED ON IN-SERVICE ENVIRONMENT AND
PERFORMANCE REQUIREMENTS
.JUmFOULJNG (AF) PAINTS - NAVY APPLICATION
..CHEMlCALAGEtfTRESISTAffTCOATINGS (CARC) -ARMY APPLICATION
-AIRCRAFT WING COATINGS - AIR FORCE APPLICATION
core O
-------
HAVY RESPONSE TO CALIFORNIA VOC REGULATIONS
O REFORMULATED PAINTS AND COATINGS TO COMPLY WITH MARINE COATINGS
REGULATIONS
o REDUCED SOLVENT (VOC) CONTENT FOR ENVIRONMBiTAL COMPLIANCE
o ENSURE CONTINUED OPB1A11ONAL AND SERVICE LIFE PERFORMANCE
o SUBSTHimON/CANCELLATlON OF PAINTS
M
* O PURSUE NEW TECHNOLOGIES FOR VOC REDUCTION
o HIGH SOLIDS PAINTS AND COATINGS
o WATH1 BASED PAINTS
o POWDER COATINGS (THERMAL PLASTIC)
O CALIFORNIA COMPLIANCE PROGRAM
o THREE YEAR PROGRAM ($3M> TO DEVELOP, TEST, AND QUALIFY
NAVY MARINE COMPLIANT PAINTS
-------
N>
cn
NAVY "CALIFORNIA COMPLIANCE- LESSONS LEARNED
O LEAD TIMES - (BEST & WORST CASE: 24 VS 45 MONTHS)
O TEST & EVALUATION (T&E): TECHNICAL DIFFICULTIES IN R&D IMPACTS
COMPLIANCE SCHEDULE
LABORATORY REFORMULATION
PERFORMANCE VALIDATION
TOXICOLOGICAL/HAZMAT REVIEW-ATMOSPHERIC CONTROL TESTING
SPECIAL APPLICATION TESTING (Lc. FIRE AND/OR HEAT RESISTANCE)
O DOCUMENTATION/SPECIFICATION UPDATE
QUALIFICATION OF VENDOR PRODUCTS
TECHNICAL GUIDANCE FOR END USER (FLEET)
REVISION OF SPECIFICATIONS TO INCLUDE APPROVED PRODUCTS
O IMPLEMENTATION OF COMPLIANT MATERIAL TO FLEET
< < EXPERIENCED SIGNIFICANT LOGISTICS PROBLEMS AND DELAYS > >
NEW PROCUREMENT OF COMPLIANT MATERIAL (CONTRACT BUYS &
NATIONAL STOCK NUMBERS (NSNs)
COMPETITIVE BUYS - SHIPMENT/DISTRIBUTION
STOCKING AND SUPPLY TRANSIT! ON OF COMPLIANT MATERIAL TO THE
SUPPLY SYSTEM
CR.MJEX
-------
NAVY LESSONS LEARNED (coifd)
O INTERIMVARIANCESNEG011ATH>INAIl.TT1REEDISmflIC1S
AND SUPPLY
O NAVY STILL COMPLETING UPDATE TO NAVAL SHIPS TECH MANUAL (NSTM
CHAPTER 631) AND SPECIFICATIONS TO REFLECT CHANGES
S O NAVY NOW Di COMPLIANCE WTTH SEPTEMBER 1991 RULE AND SEPTEMBER 1994
PENDING RULE
O SPECIALTY CATEGORIES MUST BE SPECIFIED TO ENSURE THE CONTINUED USE
OF CURRENT NAVY COATINGS
A'Bt
-------
to
-J
CURRENT NAVY COATINGS PROGRAM EFFORTS
O REFORMULATE SHIPBOARD PAINTS AND COATINGS TO REDUCE VOC CONTENT
LJMTTS TO 1HE LOWEST PRACTICAL LEVELS
o SUPERCRITICAL CO2 TECHNOLOGY
O SHIPBOARD PAINTS AND COATINGS HAZARDOUS MATERIALS DATABASE
o ENVIRONMENTAL ISSUES
IDENTIFY HAPS LEVELS IN ALL NAVY SHIPBOARDS PAINTS AND
COATINGS
_ REFORMULATE PAINTS TO SUBSTITUTE/ELIMINATE HAPs TO
COMPLY WITH STATE AND PENDING EPA LEGISLATION
o HEALTH AND SAFETY ISSUES
IDEN11FY HEAVY METALS CONTENT IN PAINTS IN EXCESS OF
PERMISSIBLE LIMITS
IDENTIFY IMPROVED PAINT REMOVAL EQUIPMENT AND TECHNOLOGY
TO MINIMIZE POTENTIAL HEALTH HAZARDOUS DURING COATING
OPERATIONS
-------
ARMY COATINGS PROGRAM
O REFORMULATED PAINTS AND TOPCOATS TO MEET CALIFORNIA VOC LIMITS
o PRIMERS
o TOPCOATS
o CARC COATINGS
M
« O CURRENT RftD ACTIONS
o REFORMULATION OF LAOUERS
O AMMUNITION ENAMEL
o HEAT RESISTANT COATINGS
O EXPANDING USE OF POWDER COATINGS
O EXPANDING USE OF ELECTROSTATIC COATINGS
DR. Mat!
-------
AIR FORCE COATINGS PROGRAM
O CURRENTLY IN COMPLIANCE WITH CALIFORNIA AEROSPACE COATINGS
REGULATION - PRIMERS AND TOPCOATS
O AIRCRAFT
o WEAPON SYSTEMS
o GROUND SUPPORT EQUIPMENT
O AIR FORCE DEPENDS HEAVILY ON AEROSPACE INDUSTRY FOR R&D OF
AEROSPACE PAINTS AND COATINGS FOR ENVIRONMENTAL COMPLIANCE
O REQUIRES R&D COATINGS DEVELOPMENT
o FUEL TANK COATINGS
o ADHESIVE STRUCTURAL BONDING PRIMER
O NO REPLACEMENT FOR CHROMIUM (VI) FOR USE IN ANT1CORROSIVE PRIMERS
-------
ANALYSIS OF PROPOSED CTG FOR MARINE COATINGS
/
O PROPOSED EPA CTG VASTLY DIFFERENT FROM CALIFORNIA MARINE COATING
REGULATIONS
O ALL MARINE COATINGS APPEAR TO BE GROUPED INTO FOUR CATEGORIES
BASED UPON CHEMISTRY AS OPPOSED TO APPLICATION
ALKYD PAINT SYSTEMS
EPOXY PAINT SYSTEMS
INORGANIC ZINC PAINTS
ANTT-FOUUNG PAINTS
O
"NOTE: THIS MEANS OF CLASSIFICATION DOES NOT CONSIDER MEANS OF
APPLICATION OR INTENDED SERVICE OF THE PAINT WHICH
DICTATES VOC CONTENT AND MAY VARY GREATLY
EPA PROPOSED CTG IS NOT CLEAR AS TO WHAT DISPENSATION WILL BE GIVEN
TO SPECIAL APPLICATION COATINGS (I.e., POLYURETHANES, HIGH SOUDS
ALUMINUM HEAT RESISTANT PAINTS, etc...)
EPA PROPOSED CTG IS LIKELY TO ADOPT CALIFORNIA *94 VOC LIMITS
O GENERAL COATING VOC CONTENT LIMIT - 340g/l (AIR DRIED COATINGS)
an MAY n
-------
ANALYSIS OF PROPOSED NESHAP FOR MARINE COATINGS
EPA NESHAP
o REGULATES 189 HAP* EMITTED DURING SHIPBUILDING OPERATIONS AND
SHIP REPAIR
HAPS LIMITS AND TECHNICAL APPROACH ARE UNKNOWN AT THIS TIME
* NAVY CONCERN THAT EPA WILL REGULATE LOW HAPs AND LOW VOC
WHICH MAY NOT BE TECHNICALLY FEASIBLE FROM AN APPLICATION
AND PERFORMANCE STANDPOINT
CALIFORNIA HAPs REGULATIONS
o AIR TOXICS "HOT SPOTS' INFORMATION AND ASSESSMENT ACT OF 1987
REGULATES APPROXIMATELY 740 HAPs (INCLUDING 189 EPA HAPs)
HAPs ARE GROUPED FOR INVENTORY REPORTING
..QUANTIFY EMISSIONS OF APPROXIMATELY 400 HAPs
..DOCUMENT PRESENCE OF APPROXIMATELY 340 HAPs
OM.MJEX1
-------
DoD TRI-SERVICE R&D COATINGS PROGRAMS
0 TRI-SERVICE ENVIRONMENTAL QUALITY STRATEGIC PLAN PROGRAM (GREEN BOOK)
O DoD PILLAR 3: POLLUTION PREVENTION
RELIANCE SUBAREA: COATINGS APPLICATION AND REMOVAL
REQUIREMENT THRUST 3B: PAINT STRIPPING AND COATINGS
O GOAL:
o PRESERVE THE ENVIRONMENT
o MINIMIZE TOXIC OR HAZARDOUS MATERIALS USED AND/OR GENERATED
o ELIMINATE POTENTIAL FINES
o IMPROVE HUMAN HEALTH AND SAFETY
o REDUCE REGULATORY REPORTING BURDEN
o REDUCE DISPOSAL, EQUIPMENT, AND CONTROL COSTS
O PROVIDES R&D TECHNOLOGIES IN THE AREAS OF:
ALTERNATIVE PAINTING AND STRIPPING METHODS
REFORMULATION OF PAINTS AND STRIPPERS
IMPROVED APPLICATION, CLEANING, AND STRIPPING EQUIPMENT
IMPROVED ABRASIVE BLASTING EQUIPMENT AND
RECOVERY/RECYCUNG/TREATMENT EQUIPMENT
MMM.M
oooceoi
CRMB
-------
U)
UJ
DoD COATINGS RESEARCH PROGRAMS
0 NON-HAZARDOUS CORROSION PROTECTION PAINTS AND COATINGS - NAVY
O NON-HAZARDOUS ANT1FOUUNG/FOUUNG RELEASE HULL COATINGS - NAVY
O ELIMINATE CHROMATE WASTE GENERATION FROM CORROSION PROTECTION
PROCESSES - ARMY, NAVY, AIR FORCE
O REDUCE HAZARDOUS WASTE FROM PAINT CONTAINER DISPOSAL - ARMY, NAVY
O NON-HAZARDOUS CHEMICAL AGENT RESISTANT COATINGS - ARMY
O REUSE/RECYCLE PAINT SLUDGE AND FILTERS - ARMY
O COST-EFFECTIVE NON-POLLUTING PAINT STRIPPING METHODS - ARMY, NAVY, AIR
FORCE
O NON-POLLUTING, LQW-VOC CHEMICAL STRIPPERS - ARMY, NAVY, AIR FORCE
O IMPROVED BLAST GRIT RECYCLJNG TECHNOLOGY - NAVY, AIR FORCE
oi Mat
-------
DoD COATINGS RESEARCH PROGRAMS (conf d)
O REDUCE HAZARDOUS WASTE GENERATION FROM PLASTIC MEDIA BLASTING - AIR
FORCE
O ELIMINATE CHROMATE WASTE GENERATION FORM PAINT STRIPPING PROCESS -
ARMY, AIR FORCE
0 REDUCE HAZARDOUS WASTE GENERATION FROM CHEMICAL PAINT STRIPPING
OPERATIONS - ARMY, AIR FORCE
O DEVELOP ENVIRONMENTALLY SAFE PAINT STRIPPING OPERATION FOR SMALL
PARTS - AIR FORCE
O TECHNOLOGY TO RECYCLE/REUSE PAINT-REMOVAL MEDIA - ARMY, AIR FORCE
O MINIMIZATION OF WASTE FROM LEAD BASED PAINT (LBP) DEBRIS - ARMY, AIR
FORCE
O MODELS/THEORIES FOR IMPROVED CORROSION CONTROL - NAVY, AIR FORCE
on. Met
aurar*
-------
R&D COST AND FUNDING ESTIMATES
O COST ESTIMATES: TECH. BASE TECH. DEMO IMPLEMENTATION TOTAL
$6,670K $40,769K $OK $47,439K
O FUNDING PRORLE:
U)
-------
NAVAL SEA SYSTEMS COMMAND (CODE 05M1) PAINTS
(per NAVAL SHIPS' TECHNICAL MANUAL • CHAPTER 631 OF 11/01/92)
Ul
ON
TT-E-490
MlLrP-24441—
MILrP-15930, F120,
.MIUE-24365
DOD-E-1115C, F30.
DOD-E-18210
DOD-E-1821
JWHL-P-24441C, P150
VTION:
DOD-E-1115C, F30
DOD-C44596 OR NAVY F25A
JDOIMX24596 OR NAVY F25A
X)D-O24596 OR NAVY F25A
DOD-P-15146.
DOD-P-15183.
DOD-024596 OR NAVY F25A
MILr&24635
MIL-E-15090, F111
DOD-C-24596 OR NAVY F25A
JMlLrE-24635
JIIILr&24635
MIL4E-15090, F111-.
MILrB5556.
MIL-E-15090, P111
DOD-C-24596 OR NAVY F25A
IIUE-24635
JX)D-P-24631B
-------
NAVAL SEA SYSTEMS COMMAND (CODE 05M1) PAINTS (cortTd)
(per NAVAL SHIPS' TECHNICAL MANUAL - CHAPTER 631 OF 11/01/92)
DOD-P-23236-.
MILrP-24647.
MILrP-15931.
MILrD-23003.
DOD-P-24648
UJ
TT-B489...
TT-V-51—
DOD-P-15328.
TT-P-1757.
TT-V-119.
.DOD-E-24607B
JDOD-C-24667
.1T-P-28(LOWVOC)
,TT-P-645B
.MlLrP-24647
---- MIL-P-15931
M1L-IV24483
PURCHACE OF
LOW VOC MATERIAL
TT-P-645B, F84 OR
MIL-P-24441C, F150
.TT-P-645B, F84 OR
MILrP-24441C, F150
."n^-645B, F84 OR
MHrP-24441C» F150
.LOCAL PURCHACE OF
LOW VOC MATERIAL
JJOCAL PURCHACE OF
LOW VOC MATERIAL
-------
NAVAL SEA SYSTEMS COMMAND (CODE 05M1) PAINTS (conTd)
(per NAVAL SHIPS9 TECHNICAL MANUAL - CHAPTER 631 OF 11/01/92)
MILC46081
MILrP-24555_.
DOD-C-24596-
.JIHIXM6081
.TT-P-28 (LOW VOC)
MILC-24380.
.JtflLrC-24380
OJ
00
-------
U)
Low-VOC Coatings for ECM
Mark D. Smith
Staff Materials Engineer
AlliedSignal Inc.
Kansas City Division *
(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
* Prepared Under Contract Number DE-AC04-76-DP00613 United States Department of Energy.
All data prepared, analyzed and presented has been developed in the context of work authorized
under the Prime Contract.
IliedSignal
AEROSPACE
-------
AGENDA
PAINTS
• Environmental concerns
• Compliance actions
• Current paint status
• Anticipated future work
• UV coatings
DRY FILM LUBRICANTS
• Environmental concerns
• Replacement actions
^IliedSignal
AEROSPACE
-------
AIR POLLUTION REGULATION
Missouri Air Pollution Rule 10 CSR 10-2.230, Control
of Emissions from Industrial Surface Coating
Operations
Applies to locations emitting more than 6.8
kilograms per day or 2.7 tons per year
KCP regulated under the provisions for painting
"Miscellaneous Metal Parts"
Emission Limit of 3.5 pounds of VOC's per gallon of
coating as applied
Effective date of Compliance; December 31,1982
IliedSignal
AEROSPACE
-------
COMPLIANCE ACTIONS:
N)
Spray painting operations voluntarily halted
Began process of developing "site plan" and
obtaining state and local EPA approval
Started VOC survey of currently used paints and
began search for "compliant" replacement paints
IliedSignal
AEROSPACE
-------
VOC's of Selected High VOC Paints
Urethane Epoxy
Enamel
Acrylic
Alkyd Epoxy Lacquer ZincChr.
Primer Primer
Teflon
Paint Systems
IliedSignal
AEROSPACE
Wash
Primer
-------
COMPLIANCE ACTIONS: (continued)
Started survey of painting industry contacts to
determine possible alternate sources of production
painting
Obtained and installed activated carbon filtering
systems for production painting area
Began obtaining and VOC-testing replacement paints
.AlliedSignal
AEROSPACE
-------
VOC's of Selected Low VOC Paints
UV Cured
Epoxy
Alkyd * Waterborne Zinc Chrm.
Epoxy Primer Primer *
Epoxy
Primer *
Epoxy * Urethane
Paint Systems
^AlliedSignal
AEROSPACE
-------
AREAS OF CONCERN IN SWITCHING
TO REPLACEMENT PAINTS
• Customer requirements for color, corrosion
protection and durability
• Maintaining Military Specifications as basis for
production paints
• Compliant paints using "exempt" chlorinated
5 solvents
• Coatings for which there were no direct
replacements, (lacquers, Teflon® paints, wash
primers, dry film lubricants)
• New paint techniques and equipment that might be
necessary
AEROSPACE
-------
PRESENT PAINTING STATUS
Almost all applications using low VOC paints
Limited use of high VOC materials within special
booth, stack emissions routed through activated
carbon filters until alternates found
Significantly reduced number of routinely used
different paint systems (from 25 down to
approximately 5)
Larger percentage of paints based on Military
Specifications and Federal Standard Color
numbers
Significantly reduced VOC emissions
IliedSignal
AEROSPACE
-------
ANTICIPATED FUTURE PAINT WORK
• Continued emphasis on high-solids, low VOC
polyurethane and alkyd enamel paints
• Reduction or elimination of chlorinated
solvent-based coatings
• Investigation of new lead and chromate-free Military
5 Specification primers
• Elimination of special booth and/or filtration of all
booths
• Evaluation of alternative coating methods
^IliedSignal
AEROSPACE
-------
ALTERNATIVE METHODS
INVESTIGATIONS
A study on powder coating is underway.
New powder coating booth and two new powder
coating guns are installed and operational.
Electrophoretic coatings are being studied. New
equipment is being obtained and set-up.
Alternate cleaning and pretreatment methods are
being studied, (alternate solvents, aqueous cleaning,
dry plasma cleaning, chromate conversion
replacements).
^IliedSignal
AEROSPACE
-------
UV CURABLE COATINGS
» The materials are essentially 100% solids and
therefore have a very low VOC content.
• The materials are very quick curing thus increasing
through-put and decreasing chances for surface
defects.
- Special curing equipment is required; curing of the
material is line-of-sight from the UV lamps.
• Clear or translucent materials work best;
opaque/pigmented materials are limited in curing by
their ability to absorb UV within the bulk of the
coating.
^AlliedSignal
AEROSPACE
-------
DRY FILM LUBRICANTS
i
Under current Missouri regulations regarding
emissions from "surface coating operations", dry
film lubricants are not included
Most of the presently used materials are high VOC,
from 6.42 to 8.12 pounds per gallon applied
Division goal of reducing emissions to "as low as
reasonably attainable" is driving substantial
investigation into low VOC dry film lubricant
technologies
IliedSignal
AEROSPACE
-------
VOC's of Selected E/M Lubricants
EL-9000
Type A EL-620 99-A 4396-S
Dry Film Lubricants
AEROSPACE
4396-BX
-------
AREAS OF CONCERN IN SWITCHING
TO REPLACEMENT DRY FILMS
• Application techniques and equipment will most
likely require substantial changes. (Licensing of
some technologies may be required.)
• Performance requirements of the present materials
are not well defined, therefore proper replacements
will be hard to define.
New low VOC versions of existing dry film lubricants
are relatively unproven in actual use which causes
some trepidation in adopting their use.
Ln
ui
^AlliedSignal
AEROSPACE
-------
LOW VOC DRY FILM ACTIONS
A group is studying dry film lubricants, surveying the
dry film market and attempting to define
performance requirements for their use.
Possible alternatives include: Dicronite®, Microseal®,
sputtering, sputter/ion treatment, electrophoretic
coatings, increased hardness coatings, and E/M's
new low VOC materials
Study will determine objective inspection techniques
for dry films
Several other small short term tests are being made
on individual parts or assemblies
^IliedSignal
tn
AEROSPACE
-------
SUMMARY
Environmental concerns about surface coating
operations prompted an analysis of coatings
materials and other compliance actions.
The painting operations equipment underwent some
modifications within the approved site plan.
The switch to low VOC paints was made as soon and
as completely as possible within certain constraints.
^IliedSignal
AEROSPACE
-------
Ul
SUMMARY (continued)
Changes in the type of dry film lubricants used are
anticipated.
Other low VOC painting techniques such as dry
powder, electrophoresis and UV coatings are being
investigated.
Investigations continue regarding other
environmental concerns such as chlorinated solvent
and hexavalent chrome reduction.
AEROSPACE
-------
(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
The Precedent-Setting Use of a Pollution Prevention Project in an EPA
Enforcement Settlement: The First DoIIar-for-Dollar Penalty Offset
Presented by:
David Nelson
EnviroSearch International
Salt Lake City, Utah
James J. Periconi
Donovan Leisure Newton & Irvine
New York, New York
157
-------
ABSTRACT
Prior to the case described in this paper, the U.S. Environmental Protection
Agency had not allowed an environmental project dollar-for-dollar setoff against a
proposed fine in an enforcement action. Typical penalty offsets were historically in the
range of 15 to 25% at the time of this settlement, although dollar-for-dollar setoffs
were theoretically available. Relatively few projects of this nature had been negotiated
with regulatory agencies, and virtually none in a RCRA enforcement action. This
pollution prevention Supplemental Environmental Project (SEP) is one of five types of
projects allowed by the new EPA policy on the use of SEPs in enforcement actions.
This paper describes the development of the legal and technical strategy utilized by the
authors to aid the client in its settlement approach to Region IX EPA. Finally, the
results of the implementation of the project to the company are discussed and the
conclusion is made that this multi-media pollution prevention project foreshadows a
significant developing state and federal regulatory trend.
DESCRIPTION OF THE FACILITY AND PROCESSES
The described facility, located in an industrialized area of San Leandro,
California, is an office furniture manufacturing company employing 65 full-time
workers in two shifts. As was true in early 1991, when the enforcement inspection
discussed in this paper took place, the business utilizes bulk materials such as sheet and
coil metals which are in turn bent, welded, assembled and painted to specifications.
Primary products are storage cabinets, bookcases, and shelving.
After metal forming occurs, the steel parts are attached to an overhead conveyor
line which runs through a chemical spray rinse system. These rinses remove cutting
oils from the parts as well as coat the semi-finished steel with rust inhibitors. The final
rinse consists of a water bath, the effluent of which is discharged via a permit to a
Publicly Owned Treatment Works (POTW). The parts, still conveyed via the overhead
158
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line, pass through a large drying oven just prior to entry into the Ransburg automatic
spraying mechanism which utilizes an electrostatic application to maximize adherence
of the paint to the steel parts. Overspray is collected in air filters which mostly
surround the circular paint booths. Remaining overspray adheres to walls, floors and
various equipment surrounding the spray system.
While the Ransburg coats a large percentage of the steel parts, they must be
finished via hand-held spray guns, operated only by the night shift. Custom furniture
not handled by the automatic conveyor system is hand painted in dedicated, three-
walled paint booths, the overspray of which is handled via filters. The facility uses
Thermal Setting Resin (TSR) paint which requires that painted parts, unlike evaporative
formulas, be returned to the drying oven for curing at 350 degrees Fahrenheit. Oven
air emissions from the curing process are regulated via a permit.
To understand fully the pollution prevention opportunities this company could
and did realize, it is important to note that the company offers custom colors on its
products to retail customers at no additional charge and with rapid turnaround. This
will be discussed later with regard to its implications in the facility's waste management
practices.
DESCRIPTION OF THE ENFORCEMENT ACTION
The facility had a joint enforcement inspection in 1991 by the California
Department of Health Services (now California Environmental Protection Agency) as
well as by EPA, with the federal government eventually exerting jurisdiction (In Matter
of Harbor Universal. Inc.. Docket No. RCRA-09-92-0001. U.S. Environmental
Protection Agency. Region IX). The EPA found that the facility had baked paint and
solvent wastes in its drying ovens, which, according to EPA, made the facility an
unpermitted Treatment, Storage or Disposal (TSD) facility subject to regulation under
the Resource Conservation and Recovery Act (RCRA). Region IX issued a
159
-------
Compliance Order requiring the facility to submit a RCRA Closure Plan for the oven,
to submit a plan for immediate compliance with all applicable regulations and to pay
penalties of $341,000.
BACKGROUND ON SUPPLEMENTAL ENVIRONMENTAL PROJECTS (SEPS)
The encouragement by EPA to use SEPs in enforcement proceedings is a natural
outgrowth of the overall importance of the pollution prevention emphasis the agency
began to apply in the early 1990's following the enactment of the Pollution Prevention
Act of 1990. See EPA's Pollution Prevention Strategy, 56 Fed. Reg. 7849 (2/25/91).
This new emphasis represented a shift away from "end of the pipe" control strategies
which, in EPA's judgment, merely shifted contaminants from one medium (e.g.,
hazardous waste storage drums on site) to another (e.g., a landfill where the wastes
were disposed, or the atmosphere to which incinerated wastes were discharged).
Much of industry, particularly larger companies, had begun, by the mid-80's, to
realize the limited value of "end of the pipe" control strategies as the costs of hazardous
waste disposal began to skyrocket. Early source reduction strategies in the organic
chemical industry, for example, are described in the prescient 1985 study by INFORM,
a non-profit, New York-based research organization, entitled Cutting Chemical Wastes.
which has recently been updated in a work (Environmental Dividends: Cutting More
Chemical Wastes 1992) that demonstrates that enormous progress has been made in
corporate attitudes to pollution prevention as well as in actual source reduction. Also
fueling this attention and focus was the then new annual rite of Toxic Release Inventory
(TRI) data, which showed in 1988, for example, that reporting facilities released 4.57
billion pounds of contaminants directly into the environment.
Under Carol Browner's leadership, the agency is likely to increase the use of
SEPS, especially pollution prevention-based SEPs. In fact, the Clinton Administration
160
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early on announced its intention to increase their use and although already found in as
many as one in ten negotiated settlements, growth in their use is expected to continue.
In the second of EPA's 1991 Enforcement Policies discussed below, EPA
targeted the reduction of 17 high risk chemicals, choosing those offering the best
opportunities for source reduction (applicability to the referenced facility discussed
later). The overall goal of EPA as of early 1991 was to reduce the total releases of
these chemicals by 33% by the end of 1992. (The authors are unaware as to whether
EPA believes it has met this goal; however, reductions are believed to have been
significant.)
EPA's Regions and program branches are to "investigate flexible, cost-effective
regulatory approaches that avoid prescriptive approaches and that rely on market-based
incentives...", (EPA Pollution Prevention Strategy, pg.10). EPA is also to "ensure
that its enforcement program seeks pollution prevention opportunities as part of
ensuring compliance" with environmental laws. "EPA will encourage the inclusion of
pollution prevention conditions in Agency enforcement settlements." As noted, the
SEPs are, in fact, increasingly employed in negotiated settlements, with pollution
prevention SEPs in the lead. The strategy is to "incorporate prevention into every
aspect of the Agency's operations in program and regional offices/
The enforcement-related side of this policy is developed in two EPA guidances:
1. "EPA's Policy on the Use of Supplemental Environmental Projects
(SEPs) in Enforcement Agreements" (2/12/91) defines those projects, other than those
required to correct the underlying violation, which a defendant or respondent in
administrative proceedings "may undertake in exchange for a reduction in the amount
of the assessed civil penalty". Acceptable projects include:
i. Pollution Prevention Project: one that "substantially reduces or prevents
the generation or creation of pollutants through use reduction (i.e., by changing
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industrial processes, or by substituting different fuels or materials) or through
application of closed-loop processes";
ii. Pollution Reduction Project: one that "goes substantially beyond
compliance with discharge limitations to further reduce the amount of pollution that
would otherwise be discharged into the environment...[e.g.] that reduces the discharge
of pollutants through more effective end-of-pipe or stack removal technologies; through
improved operation and maintenance; or recycling of residuals at the end of the pipe."
iii. Environmental Restoration Project: one that remediates adverse public
health or environmental consequences, "to enhance the environment in the vicinity of
the violating facility."
iv. Environmental Auditing Project: not one "that represents general good
business practices," though it may be considered by EPA "if the defendant/respondent
undertakes additional auditing practices designed to seek corrections to existing
management and/or environmental practices whose deficiencies appear to be
contributing to recurring or potential violations."
v. Public Awareness Project: one that includes publications, broadcasts, or
seminars or "which underscore^] for the regulated community the importance of
complying with environmental laws or disseminate[s] technical information about the
means of complying with environmental laws," including sponsoring industry-wide
seminars. For those considering this SEP option, it is important to note that the project
must be publicly advertised as being part of a consent agreement with the EPA in
satisfaction of an environmental violation.
Importantly, there must also be a "nexus" or relationship between the original
violation and the supplemental project._A vertical nexus exists when the project
reduces pollutant loadings to a given environmental medium to offset earlier excess
loadings of the same pollutant to the same medium. A horizontal nexus is described as
when the project either gives 1) relief for different media at a given facility or 2) relief
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for the same medium at different facilities. All SEPs must significantly reduce the total
risk posed to public health or the environment by violations. Additionally, all SEPs
must be "directly related to addressing compliance problems within the industry within
which the violation took place."
While EPA will not generally allow a SEP to be merely a sound business
practice that a facility should do anyway (e.g. a basic environmental auditing program),
the agency makes an exception in the case of pollution prevention projects alone. The
reason is the pollution prevention projects in particular among SEPs have the
"advantage of potentially providing significant long-term environmental and health
benefits to the public," as well as also being a sound business practice.
Similarly, pollution prevention SEPs can also (unlike other SEPs) include
studies which "will be eligible for a penalty offset when they are pan of an Agency-
approved set of pollution prevention activities at a facility and are designed to correct
the violation..." The goal is to encourage pollution prevention studies needed to
determine appropriate measures. The "size of the penalty offset may include the costs
of the study." Finally, the amount the fine is lowered can reflect the actual dollar
expenditures for SEPs, but by no "more than the after-tax amount the violator spends
on the project." However, new equipment may be depreciated as a business expense.
2. The second importance guidance, issued the same month as the first
guidance and the same day as EPA's Pollution Prevention Strategy, is EPA's "Interim
Policy on the Inclusion of Pollution Prevention and Recycling Provisions in
Enforcement Settlements" (2/25/91). This policy is intended to be used specifically for
those cases where a pollution prevention program will be part of an enforcement
settlement. It is this document that contains the list of 17 chemical wastes which EPA
has targeted for reduction. Additionally, the policy describes "good faith" as a factor
in the settlement: "(t)he willingness of a respondent to correct the violation via a
pollution prevention project can be one of the assessment factors used to adjust the
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'gravity1 component of the penalty." "Voluntary" and "timely" disclosure of the
offense may also be taken into account in the final settlement.
At the time of the agency negotiations regarding this enforcement action, in late
1991, SEPs had been used sparingly, and in fact, EPA's (new at the time) Pollution
Prevention Information Clearinghouse (PPIC), tasked with recording all SEPs from the
various EPA Regional offices, headquarters and states, knew about only four SEP
settlements. Used mostly in TSCA, EPCRA, and FIFRA cases up to that point, the
reduction in fines were on the order of only 10 to 25% of the amount spent on the
pollution prevention project.
Since that time, SEPs have seen widespread use, and are currently estimated by
EPA, as noted earlier, to be used in one in ten enforcement cases and growing. EPA's
1992 National Penalty Report, released in the late spring of 1993, indicates there were
409 SEPs negotiated in all programs during 1992. The agency estimated their dollar
value at $50.1 million (though the figure has met with considerable controversy as
being too high or too low), with EPA Regions reporting 222 SEPs. The mobile
sources air program added 187 SEPs, of which 183 were public awareness projects.
More than half of the regional SEPs were pollution prevention projects with TSCA or
EPCRA cases comprising 40% of the total. The authors believe many of these
settlements arose from "paperwork" reviews such as failures to file Pre-manufacture
Notices (PMNs), or Form Rs, respectively, and not the result of investigation-intensive
inspections (especially RCRA inspections) conducted by state or federal agencies.
According to EPA, programs other than mobile sources, TSCA and EPCRA - e.g.,
RCRA - each generated no more than 5% of such cases.
DEVELOPMENT OF LEGAL/TECHNICAL STRATEGY
The attorney/consultant team was led by the authors, whose backgrounds were
ideally suited for this particular case. Prior to entering private practice, Mr. Periconi
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had been an Assistant Attorney General in the Environmental Protection Bureau of the
New York Attorney General's office for five years in the early to mid-1980's
prosecuting early criminal as well as civil hazardous waste, air, water and wetlands
violations; subsequently, he was Chief of the Hazardous Waste Enforcement Bureau for
the New York State Department of Environmental Conservation. Prior to starting his
consulting firm in 1985, Mr. Nelson was a former multi-program enforcement officer
for several regulatory agencies in the State of Utah and served on several EPA
oversight committees tasked with reviewing the implementation of RCRA and
CERCLA in the early 1980's. While with the agencies, Mr. Nelson was involved with
several high profile enforcement cases.
This background allowed the team to realize immediately the severity of the
enforcement action both on the face of the allegations and in early conversations with
agency personnel, but also the opportunities the company could realize by a substantial
program aimed at not only addressing EPA's immediate concerns, but also going far
beyond the enforcement action. Our ultimate goal was not only to keep penalties low
while satisfying satisfy the agencies, but to help the company turn its overall
environmental management program into a cutting-edge business advantage by reducing
its production costs.
The initial step was to evaluate the operational as well as strictly environmental
aspects of the facility in a broad, unrestricted sense, without emphasizing the
enforcement action. In other words, the team was not focused on the hazardous waste
paint-baking episodes, as the correction of this problem was obvious, namely, stop the
practice and undertake RCRA closure; rather it looked at the facility as a whole, all the
time seeking pollution prevention opportunities that would be incorporated eventually
into the plan as well as the day-today business activities of the facility.
While facility personnel had a basic understanding of the regulations, and was
striving to meet regulatory requirements, it was apparent that the waste handling
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practices were grossly inefficient to the point that it was a clear financial burden,
enforcement and penalty issues aside. Major waste streams consisted of a great deal of
paint overspray over large portions of the painting rooms and surrounding environs,
necessitating the use of large quantities of thinner for cleanup. Additionally, paint and
solvent contaminated rags were overly abundant as were discardable paint filters, often
used well beyond their effective use to the point of over-saturation. To attempt to
control the large amount of paint overspray on the floor, large quantities of cardboard
were placed on the floor, sometimes layers deep, typically well saturated with paint and
therefore quite heavy. This waste material was shipped off to a TSD in pallets, priced
by its weight, as an expensive hazardous waste.
Additionally, large quantities of waste paint thinner were generated from
cleaning of guns, lines and other miscellaneous chores. While much of this was
reclaimed by the company to which the facility sent these wastes, those wastes with a
higher proportion of waste paint to solvent could not be reclaimed. Interestingly, the
facility also generated enormous amounts of thinner waste due to its marketing success
in offering custom colors to clients. The result of this successful marketing effort was,
however, the very frequent changing of colors, including the entire flushing of long
lines thick with paint. This created, of course, an externality not charged to customers
in higher prices for custom lines of products.
Additional potential environmental pollutants, which were reviewed as pan of
the waste minimization audit, were rinse bath chemical additives from the wastewater
stream discharged to the POTW, via permit, as well as the paint solvent emissions in
stack gases from the drying ovens, also regulated by a permit. Both permits were
current for both emissions; however, the team looked at pollution prevention
opportunities with these wastes as well.
Readers familiar with the pioneering work of eminent pollution prevention
researchers Joel Hirschhorn, Ph.D. (Hirschhorn & Assoc., Washington D.C.) and
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Robert Pojasek Ph.D. (GE1 Consultants, Boston, Mass.) know that non-technical
barriers, sometimes called "soft" or behavioral barriers, predominantly exist within a
facility, the result of which is the typical creation of substantial disincentives for
pollution prevention opportunities. In other words, the greatest gains for pollution
prevention opportunities are not necessarily or even typically found in high-tech,
capital-intensive, R&D solutions; rather they exist in recognizing, modifying,
empowering and rewarding facility personnel behavior that precludes the generation of
unnecessary amounts of waste. The employees are closest to the problems, and
therefore, closest to the most cost-effective, low-tech solutions. It often requires,
however, an independent review by outside expert consultants, to identify these
industrially dysfunctional, competetively-disadvantaged behaviors. This facility was no
different than most others we have consulted to and in this regard, we noted the
following during our review:
- Communication barriers were significant between management and workers
and were further hampered to a significant degree by language barriers;
- Employees were not empowered nor rewarded to bring forth solutions to the
facility's daunting environmental problems;
- Plant engineers and senior managers were convinced that they had investigated
every possibility for waste minimization and that no possibilities existed to realize
further benefits;
- The night shift posed the greatest threats to the environmental health and
safety (EHS) programs. This was due to the fact that no programs existed to sensitize,
empower, train and reward (particularly) night shift personnel (nor did they exist to a
large degree for the day shift) in solving these problems. Thus, they festered, and
ironically presented each new day shift with an ever-increasing, downward spiral ing
environmental, health and safety headache. The day shift, almost entirely out of touch
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with the night shift regarding EHS matters, inherited on a daily basis problems
seemingly with no end.
- Pollution prevention opportunities were so apparent and numerous that the
prevailing attitudes by all personnel virtually precluded them from seeing them.
These barriers were by far the biggest hurdle to overcome in developing an
entirely different environmental, health and safety corporate ethic. Once this was
accomplished, with the direct and sincere involvement of the company CEO,
sometimes on a daily basis, the facility began its journey to turning the facilty around.
It is important to note that management was understandably jaded by the
regulatory process insofar as they had received incorrect information from a variety of
sources as to proper management of paint wastes. The company had a plant engineer
trying to "keep up" with changes in regulations on a "part-time" basis in a state known
for its aggressive environmental agenda (California). Thus, he felt he had to rely on
two seemingly credible sources which, in fact, caused problems. The paint salesman,
whose incentive was to sell more paint, indicated that the baking of paint wastes was
the "industry standard" and that it met regulatory restrictions on VOC content. (Of
course, these standards have become ever more stringent in states like California or
New York, so that what was an "industry standard" in one year would no longer be so
a year or two later).
Perhaps more troubling was literature from its main competitor, which we
presented to EPA during the negotiation phase, virtually showcasing its baking of paint
waste in its ovens to reduce volume! The article was professionally produced,
complete with a photograph of the proud facility operator holding a dry bucket of paint
in front of a drying oven almost identical to our client's. Contributing to this problem
was the fact that the competitor is a very large player in the office furniture business,
and our client had to (and continues to have to) compete with far less resources, not the
least of which were, and are, environmental.
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After it completed the environmental and waste minimization audit, the team
exhaustively researched all uses of pollution prevention settlements in administrative
consent agreements. As stated above, only four cases had at the time been registered
with the PPIC, which at the time was just getting underway. Additionally, we checked
numerous state and Regional EPA sources for SEP-like agreements, only to be
dismayed by the lack of a centrally-organized source. Not surprisingly, each Region
had its own "style" or writing and disseminating such orders, resulting in difficulty in
making comparisons and compiling a real profile, based on scant details of the
application of the SEPs policy in many Regions' consent agreements. (The reader is
cautioned that the authors believe EPA still lacks a centrally-organized, easily
retrievable source of detailed SEP information. We attempted to update this paper at
the time of publication only to find that although there are some gross numbers
available regarding SEP settlements, see 17 Chemical Regulation Reporter 545 (BNA)
6/4/93, useful information is not easily obtainable. Neither LEXIS nor Westlaw, in
addition, keep such information in particular or non-adjudicatory administrative
settlements in general on line).
We were well armed when we first met with Region IX and were fluent in what
we believed were the cases negotiated to that date as well as a pollution prevention plan
and a number of reasons why a SEPs approach was appropriate. To our client's delight
and EPA's credit, the agency recognized the effort and relied on us as a source of
expert information.
We presented to EPA a very comprehensive, detailed waste management study
performed at the described facility, which included raw material use, a water "budget"
for all uses and processes, solid as well as hazardous waste outputs, and a
comprehensive materials budgets, among other measures.
Additionally, we proposed nine administrative measures, aimed at correcting,
influencing or empowering employee behavior. These included:
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- Issuing a Pollution Prevention Policy from management to employees;
- Assigning a person or team within the plant to manage and direct the program;
- Having this person or team report progress routinely to the company president;
- Conducting employee training on pollution prevention technologies in the
fabricated metal industries;
- Monitoring of pollutant volumes more closely to observe changes and trends;
- Implementing inventory control in the paint storage room, and recycling of
unused paint after six months or less;
- Minimization of overpurchases of special colors;
- Purchasing frequently-used colors in bulk to minimize empty containers.
We proposed nine operational changes fixed on hands-on solutions to direct
reduction of hazardous waste/material generation. These included:
- Elimination of the unnecessary use of cardboard on the floors;
- The use of collection troughs to reduce overspray falling to the floor;
- The use of metal grating to create a better floor drainage and collection system
in painting and storage areas;
- Improving paint transfer techniques in storage room using dedicated barrel
pumps, funnels, spigots, or other devices;
- Installation of dedicated distribution systems for the most commonly used
paint colors to minimize line flushing;
- Exploration of the possibilities of running lots of one color per week or one
color per night;
- Exploration of the business pros and cons of offering a more limited choice of
colors;
- Reviewing adequacy of equipment maintenance practices;
- Reviewing adequacy of operator training and feedback for process
improvement.
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We made one product reformulation suggestion that the facility manufacture
furniture of pre-coated stock (recognizing that this may be a type of "generator shift" of
hazardous waste generation in that some facility would need to paint the steel).
The nine production process changes were the:
- Investigation of newer spray guns and centrifugal spray systems to reduce
overspray;
- Reduction of open space between parts on the conveyor system (this greatly
reduces amount of overspray);
- Consideration of painting some parts only by the Ransburg or only by the
spray gun rather than by both;
- Measurement of the Ransburg's efficiency and comparison to the design
specifications;
- Reduction of the pressure in the spray guns;
- Installation of a baffle system for the collection of overspray;
- Modification of the filter systems so as to collect less overspray (this allows
more paint to go to the part);
- Review of the efficiency of the cleaning and rinsing system to reduce water
use and load on the POTW.
- Installation of a dedicated in-plant paint thinner recycling system.
Finally, we wanted to study six raw material changes, some of which were
R&D based, in the sense that the realization of immediate benefits were less tangible,
and would require some investment in time and follow-up to investigate. These
changes were:
- Powder coatings;
- Water-based coatings;
- Radiation-curable coatings;
- Dip tank system innovation;
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- Alternative thinners and solvents;
- Alternative cleaning and pre-coating chemicals.
As the facility implemented the Pollution Prevention Plan, we learned that
certain changes worked while others did not, a situation not unexpected. For example,
the total elimination of cardboard to collect overspray on the floor seemed to be a
highly desirable goal because it became quite saturated and heavy and was therefore
very expensive to dispose of as a hazardous waste. Several alternatives to this were
explored; however, the facility returned to its use, but currently uses this procedure
quite sparingly. It is not placed several layers thick, is strategically placed so as to
provide maximum benefit and is removed prior to saturation. Importantly, however,
its use has been curtailed by overall better housekeeping practices, advances in the use
and maintenance of the spray paint systems and other behavioral changes on the pan of
employees, the overall result of which is continued waste minimization. This is
precisely the desired effect of a rigorous pollution prevention plan in that it constantly
provides the facility with feedback of its successes and failures in order to maximize
beneficial alternatives.
It is important to note that the facility had, from time-to-time, investigated
alternative coatings in the past; however, the company had no system or mechanism to
rigorously follow new trends in the coatings industry. Again, the company was in a
sense "trapped" by its small size, and was unable to participate in a program to keep it
on the cutting-edge of coatings technologies which would not only help cuts its
production costs but greatly benefit the environment as well.
While we discussed the SEP policies and this facility's proposed Pollution
Prevention Plan as a SEP at the December 1991 meeting with EPA, we did not think it
prudent to make the case for the Pollution Prevention Plan meriting a dollar-for-dollar
SEP setoff at that initial meeting. Our goal at that point was to get EPA interested in
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how implementation of the Plan would mean long-term compliance and pollution
prevention for this facility. EPA's lawyers and technical staff were cautiously
enthusiastic about the possibilities of the Plan for achieving these long term compliance
and source reduction goals.
At the end of the meeting, we were asked to and did prepare a detailed, written
proposal integrating the Plan into the SEPs policy as applicable to this particular
enforcement action, and to make clear just exactly what kind of a monetary setoff
against the fine we were seeking. In preparing the written proposal, we did so because
we believed in the case for such a setoff, where the proposed fine represented a
substantial penalty for such a small company, where the company was sincere in
eliminating the problem, and EPA staff was thoughtful and sophisticated about the
issues, and seemed eager to participate in a new, developing, and promising pollution
prevention program recently outlined by the Agency.
The agency responded favorably to the detailed proposal, the legal and technical
personnel going out on a limb somewhat in granting what they knew would be the very
first dollar-for-dollar setoff against a proposed penalty. We attached the Pollution
Prevention Plan to the Consent Agreement and Final Order (CAFO) which required
four quarterly reports to be made, with the consultant acting as the "third party" auditor
in order to certify to EPA that the expenses and changes had been made as proposed.
It is important to note that money not actually expended on implementation of the
pollution prevention plan would have to be paid to EPA as an additional penalty; thus
the facility owner had to fully implement the Plan as agreed. The dollar-for-dollar
setoff was for the full $218,000 for implementation of the Pollution Prevention Plan,
and that after other penalty reductions, the company only paid a $93,000 fine.
We believe EPA's policy to allow study and analysis of pollution prevention
projects (unlike other SEPs) to qualify for a penalty offset is a wise one. There is
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typically a series of trials and errors before the right combination of projects can be
determined, and the project here was no exception to this rule.
SUCCESS OF THE STRATEGY
The attorney/consultant team's success in persuading EPA relied substantially
on the fact that we helped EPA understand how full implementation of this facility's
Pollution Prevention Plan would aid the agency's own goals of 1) incorporating such
plans into enforcement settlements with a strong financial incentive to do so and; 2)
reducing pollutant loadings to the environment, thus lowering risk to human health and
the environment in the short and medium runs and; 3) improving overall environmental
compliance in the long run, thus avoiding the need to expend scarce agency
enforcement resources repeatedly on the same "problem" facility. We got EPA very
interested at the December 1991 first enforcement negotiation meeting in having the
facility implement the Plan and, more importantly, take numerous steps to ensure long-
term, overall facility compliance with all environmental regulations.
Additionally, the plan was a success because
1. We supported the legal and policy argument that this case was ideally
suited for a pollution prevention project through a highly technical evaluation of sound,
implementable pollution prevention measures;
2. We found that sophisticated technical and legal staff at EPA understood
that the facility's problems went far beyond the immediate RCRA violations that
resulted from the inspection, and that therefore, the solution had to be comprehensive;
we knew that ultimately these regulators were beyond a "let's hit 'em for everything
they're good for" approach of maximizing the fine, and truly wanted to see the facility
become compliant in an overall sense. Indeed, we found EPA staffers working on this
project eager to be involved with a cutting-edge, comprehensive pollution prevention
plan.
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3. We had full support from senior company management after careful
education about the benefits of pollution prevention projects, and informing them that
enforcement actions could possibly recur unless attitudes genuinely changed and the
level of training and professional assistance were increased; this change began with the
development by the President of the company of a comprehensive policy that we did
not write for him, but which we insisted that he develop based upon our discussions;
based upon these developments, EPA viewed management's active "willingness...to
correct a violation via a pollution prevention project" as "one of the assessment factors
used to adjust the 'gravity' component of the penalty." Interim Policy at p.6.
4. Our plan met both the horizontal and vertical nexus requirements of the
SEPs policy. It met the horizontal nexus test because decreasing the amount of
hazardous wastes generated in the paint spray process would automatically reduce air
pollutants generated, i.e., "relief for different media at a given facility." SEPs Policy at
p.6. It met the vertical nexus test because the project would reduce the amount of
paint waste created by overspray, and reduce spray paint line flushing with solvents, or
entirely eliminate the use of solvents by materials substitution. Thus, this facility's
SEP had a vertical nexus with the violation because the SEP "follow[ed] a violation
back into the manufacturing process to address the root cause of the pollution." SEPs
Policy at p. 6.
5. Three of the 17 targeted chemicals in the SEPs policy for reduction were
used and generated as waste at the facility; these are methyl ethyl ketone, methyl
isobutyl ketone, and xylene. Reduction in their use thus directly met EPA's goals to
reduce the overall pollutant burden on the atmosphere;
6. While it was not our (or the facility's) intention to do so initially, our
plan reflected a true "multi-media" approach, foreshadowing federal and state programs
that were then proposed and are now underway. These initiatives represent EPA's and
the states' desire to undo the historical fragmentation of environmental regulation on a
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program by program basis, and to replace the patchwork system we all currently labor
under with a "holistic" approach that deals with all programs and the systemic problems
in management and operation that lead to environmental violations.
The company's success, on the other hand, began with the reduction in penalties
assessed, of course, the relief that while an enormous amount of money would have to
be expended, $218,000 of what had been a pure penalty would at least go toward
improvement of facility operations. Thus, the company's success and reward was the
longer-lasting one of lower operational costs, less of the heavy, solvent and paint-
saturated cardboard having to be hauled away as hazardous waste, at great expense,
thus contributing to a larger bottom line. In addition, the company benefited as greater
sensitization of management and employees to opportunities for greater corporate
environmental citizenship took hold.
Perhaps the truly satisfying reward, however, were the results of a recent
agency inspection of the facility wherein the findings reported that "all waste
manifesting and profiles were accounted for" and, reflecting the long-term commitment
the company made to its employees, that "training programs were in place for
employees handling hazardous wastes and that training logs were signed by each
employee." Additionally, all waste storage containers were properly covered, stored,
labeled and were in fact detailed as "excellent." The facility is subject to California's
famously rigorous SB 14 waste minimization program, and the inspection found it to be
implemented "with reductions in waste production." Finally, the agency wrote:
"Significant improvements in all areas of hazardous waste management. Positive
attitude of [the facility] has created an environment of reinforcing values for hazardous
waste reduction and management."
LIMITATIONS OF SEPS
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This paper does not discuss in detail the limitations and criticisms to SEPs, yet
it would be incomplete without at least briefly listing them. Some criticisms that have
been leveled are:
1. Pollution Prevention SEPs may provide a disincentive for voluntary
pollution prevention projects.
2. EPA is reluctant to grant additional dollar-for-dollar settlements, and the
agency has been criticized for the generosity of this particular settlement. However,
the authors strongly believe that given the appropriate circumstances, potential violators
should nevertheless attempt to secure a similar settlement.
3. The Government Accounting Office (GAO) has suggested in a July 1992
report that EPA is without authority to "divert" to corporate violators dollars that
should go into the Federal Treasury. EPA intends to continue to use SEPs in settling
enforcement cases until this is worked out.
4. Projects consistent with EPCRA and other federal and state statutes
mandating pollution prevention or source reduction will not qualify for offsets because
they are already required.
5. Once a particular company has effectively been "put on notice" by
agreeing to implement a SEP, particularly a pollution prevention SEP, it will be
difficult for other facilities under the same parent corporation to ignore implementation
of similar programs.
CONCLUSIONS AND RECOMMENDATIONS
Pollution prevention has early on received a high profile under the Clinton
Administration, and is likely to receive ever greater attention. As states turn up their
environmental agendas, they will also increasingly utilize pollution prevention
techniques to abate environmental penalties. Already, several successful citizen groups
are using SEPs in public enforcement actions.
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It is important to note the skyrocketing use of SEPs; however, equally important
is the realization that these are likely used in "paperwork violations" of EPCRA and
TSCA. Opportunities exist, therefore, for creative use of SEPs in more investigation-
intensive enforcement actions such as RCRA violations. Should you embark on such a
venture, it is our hope that you or your clients realize the overall benefits that our client
gained in fully implementing a realistic and rigorous pollution prevention program.
But based on our experience in this case, and in discussing Pollution Prevention
Plans with a number of clients, we believe there are certain changes that can and should
be made in implementation of the SEPs program.
First, EPA must figure out a way to resolve an inherent tension between the
time needed to examine and experiment with numerous possible pollution prevention
projects and restrictions occasioned by certain agency requirements. These are, in
particular, the apparent need to quantify project costs precisely up front in the
administrative settlement, at a time when the facilty in an enforcement action wants to
maximize the amount of penalty settoff, rather than defer any decision to make
substantial capital expenditures pending further study of their utility to the particular
facility. As the INFORM studies of 1985 and 1992 and researchers Hirschhorn and
Pojasek have shown, so many pollution prevention projects do not require large capital
investments so much as changes in facility attitudes and procedures. (This paper
describes this very occurrence with our client). Yet EPA requires in the administrative
order a fixed dollar amount of pollution prevention projects "up to which" amount an
offset will be made. Thus, there is an overemphasis on both sides on selecting big-
ticket items (e.g., large capital expenditures for equipment replacement, which may or
may not contribute to pollution prevention) in costs terms. This is an unfortunate
emphasis.
The second agency requirement that is inconsistent with the trial and error
nature of maximizing pollution prevention opportunities is the insistence that all
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projects be completed within an artificially short time-frame, namely, in our case, only
six months. It may have been a RCRA program requirement or a function of personnel
caseloads and workplans, but our only disagreement with EPA after it had accepted our
basic proposal was its insistence that we compress a one-year program into six months,
for purposes of signing off on the Consent Agreement and Final Order. We were told
informally that if things were going well, technical staff would have the discretion to
extend beyond six months the time in which we had to spend the full $218,000 that was
the maximum setoff allowed in the settlement for implementation of the Plan. It is not
easy to spend $218.000 wisely in six months at a small facility when study of various
alternatives, to determine the right combination of projects, itself could take six or
more months. Why force facilities to spend money (failing which, the unexpended
portion would be added to the penalty amount) before a thoughtful examination of what
a facility needs has been completed? Pollution prevention engineering is increasingly
receiving R&D investments, yet many solutions are just "out of reach" of the
manufacturing sector within perhaps a dictated regulatory time frame. The SEP system
should allow for such cases where a violator who genuinely wishes to participate in the
"cutting-edge" of pollution prevention technology is allowed to make the proper
investment over an agreed-upon time frame.
Our third conclusion and suggestion for improvement is that it is a mistake to
link penalty offsets solely to the dollars expended on the pollution prevention project
rather than on the amount of reduction of pollution produced by the project. Again, if
the low-tech, relatively inexpensive solution results in a significant source reduction or
pollution prevention, why not reward the regulated entity for its ingenuity in finding
inexpensive solutions?
Our final suggestion is that the agency complete and carry out its "two percent
project", between its Office of Enforcement and Compliance Monitoring, the
prerequisite to finalizing the 1991 Interim Policy discussed above. Regions have in
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theory been encouraged to continue to expand the use of pollution prevention
conditions in enforcement settlements, as part of long-term strategic planning for multi-
media enforcement, according to EPA guidances. The authors believe that this
initiative must move forward expeditiously, despite the lag in EPA efforts that we are
now experiencing, typical when there is a change of administrations in Washington.
The concern is that as leading states like New York and California move forward with
their own multi-media and pollution prevention efforts, absent a coherent and "final,"
not "interim" policy on such efforts, they will adopt only those pieces of EPA's
program, if any at all, that seem suitable rather than the entire package. Already
California, for example, has despite the leadership of California EPA Administrator
Jim Strock, the author of the two 1991 U.S. EPA guidances that are the foundation of
SEPs and the use of pollution prevention projects in enforcement actions, adopted a
restrictive form of the SEPs program - one in which most of the elements are in place,
except that the maximum amount of setoff is only 25% of the penalty. Worse, in New
York, which has begun an aggressive multi-media enforcement program, pollution
prevention requirements are essential in settlements, but without any penalty setoff
whatever (except for government entities for certain "environmentally beneficial"
projects). Thus, there is a real potential for the States to adopt the stick without the
carrot (as in New York), or without a very big carrot (as in California). We believe
that restricted State budgets and the need to fund agency budgets has taken precedence
over good public policy - one that recognizes that the benefits to the society at large
from pollution prevention programs are so enormous that industry deserves the
maximum amount of incentive to undertake such programs.
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
ARMY POLLUTION PREVENTION SUCCESS STORIES
Jack Hurd
Army Acquisition Pollution Prevention Support Office
5001 Eisenhower Ave.
Alexandria, VA 22333
Mark W. Ingle
Ocean City Research Corporation
1745 Jefferson Davis Highway, Suite 702
Arlington, VA 22202
INTRODUCTION
The United Stales Array Materiel Command purchases over $95 billion worth of
equipment and supplies every year.1 To ensure that the acquisition programs purchasing these
items address the life-cycle pollution prevention concept, the Army Acquisition Pollution
Prevention Support Office (AAPPSO) was established in 1989. The overall AAPPSO
program goal is to prevent as much pollution as possible by designing environmentally
friendly equipment and support systems from the start and not simply treating whatever toxic
by-products happen to be generated.
Since 1989, the AAPPSO has had a number of pollution prevention successes related
to Volatile Organic Compound (VOC) and hazardous air pollutant reductions. The programs
and the key success areas are listed below:
Program Success
Implementation of Low VOC Verified system performance.
Electrodeposiied Epoxy Implemented new military
Coating on Array equipment specification.
Started reducing VOC
emissions from Army
procurement activities.
Implementation of Non-VOC Verified systems performance.
based Cleaning Compounds Conducted performance tests.
on Army Equipment Implemented use of new products.
Replacement of Ozone Depleting Developed technically valid
Compounds (ODCs) in Array substitution plan.
Equipment Started eliminating ODC based
systems through redesign.
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Program Success
Elimination of Spray Verified elimination process.
Chromate Conversion Conducted site implementation.
Coating Applications.
The technical efforts described above will be discussed in detail. However, these
successes represent only a few of the many AAPPSO project areas. Some of the other
important programs being managed by the AAPPSO include; elimination of chromic acid
plating rinses; development of powder coatings for Army applications, development of a
technically valid, comprehensive plan for eliminating cadmium plating from Army equipment;
training of Army acquisition personnel at all levels regarding the need for effective acquisition
pollution prevention; development and distribution of over 6000 copies of the "Materiel
Developer's Guide for Pollution Prevention;" and generation of the contractual support
documents the Army requires to task contractors to implement pollution prevention.
BACKGROUND
Army industrial manufacturing processes are an essential part of the military
equipment rework/overhaul process. Army manufacturing processes are quite similar to those
in private industry and must comply with the same Federal, state, and local environmental
regulations. Any operating or overhead costs associated with the procurement, use, or
disposal of hazardous materials adversely impacts facility costs and does not contribute to an
improved final product. In the past, expenses related to hazardous materials were considered
a "cost of doing business." Today, through pollution prevention implementation, the Army
does not have to pay for pollutants that do not add value to the product.
In addition to having to fund the normal "cost of doing business" associated with the
use of hazardous materials, excessive pollutant discharges can lead to permit violations.
During the 1991 - 1992, both Red River and Letterkenney Army Depots violated their air
quality permits. These violations were related directly to excessive Volatile Organic
Compound (VOC) emissions from painting and finishing. These permit violations have lead
to significant changes in depot operating procedures.
The most effective means of saving money and preventing permit violations is
pollution prevention. Pollution prevention has also been mandated as Federal and state law.
The Federal Pollution Prevention Act of 1990 established an overall policy that twenty-eight
states have adopted as part of their environmental regulations. Army VOC pollution
prevention programs are designed to ensure compliance with these laws and to simultaneously
improve product quality. Thus, pollution prevention programs help to minimize operating
costs, avoid NOVs, and comply with pertinent environmental regulations.
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DISCUSSION
The following discussion sections highlight the key success stories. Each discussion is
roughly divided into sections describing the program background, technical results, and
conclusions.
Implementation of Low VOC Electrodeposited Epoxy Coatings on Army Equipment
In 1989, the Army Acquisition Pollution Prevention Support Office (AAPPSO),
Armaments Research. Development, and Engineering Command (ARDEC), Tank and
Automotive Command (TACOM), and Belvoir Research Development and Engineering Center
(BRDEC) initiated a program to include the electrodeposisted epoxy (E-coat) coatings used by
the automobile industry in the Army Chemical Agent Resistant Coating (CARC) family of
materials. The program was designed to effectively leverage the existing knowledge within
the automotive industry and thus minimize the required Army investment.
E-coat systems utilize a low Volatile Organic Compound (VOC) epoxy paint emulsion
in a completely recyclable water bath. Vehicle bodies or other complex parts are electrically
charged and lowered into the E-coat bath. The electric current flowing through the bath
causes the epoxy paint to "plate-out" on all conductive surfaces. Because the epoxy coatings
are non-conductive, current densities increase around defects or difficult to coat areas. The
increased current densities cause additional coating deposition. Thus, the coating application
process causes epoxy to be deposited uniformly on virtually all conductive surfaces.2
Ocean City Research Corporation (OCRC) worked with ARDEC and TACOM staff to
evaluate the corrosion control performance of an environmentally acceptable, low-lead, low-
VOC, E-coat formulations. OCRC prepared test panels with the proposed E-coat material and
with conventional spray applied epoxy primers. Simultaneously, TACOM coated tactical
vehicle bodies with the proposed materials. The panels and vehicles were then exposed to the
natural marine environment for a period of one-year. Data were collected tracking the
substrate corrosion allowed by the various corroding systems. Test results indicated that the
proposed E-coat material provided superior substrate corrosion control performance relative to
the currently applied spray epoxy primers.
Upon completion of the technical corrosion control performance evaluations, the
proposed E-coat material was evaluated by BRDEC for compliance with the rigorous CARC
requirements. The CARC system must resist absorption of chemical warfare agents, prevent
substrate corrosion, withstand normal wear, and provide effective camouflage within the
visible light and IR range. BRDEC tests indicated that the proposed E-coat material was an
effective primer that satisfied all CARC performance requirements.
A new military specification, MIL-P-53084, for the electrodeposited epoxy was
generated. This specification allowed Army acquisition activities to "call-out" E-coat in
procurement projects. This new specification has already been invoked on the Family of
Medium Tactical Vehicles (FMTV) program and will reduce VOC emissions, improve product
quality, and cut costs in the near future.
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The major TACOM FMTV procurement project for medium duty trucks was one of
the first to require E-coat Because the E-coat system is inherently low in VOCs and has a
near 100 percent transfer efficiency, primer coating VOC emissions arc minimized. Assuming
that 10,000 trucks will be procured by the Army over the life of the contract, E-coat
implementation could reduce primer VOC emissions by approximately 3900 tons.
In addition to VOC emission reductions. E-coat is a far more effective corrosion
control primer than the older spray primer systems. Data is not yet available regarding how
much corrosion control maintenance can be avoided by using E-coaL However, it has
primarily been the use of cathodic E-coat over a zinc-phosphate prelreatment that has allowed
the commercial automotive industry to give 7-year or 70.000 mile corrosion warranties.2
Finally, E-coat implementation will save the Army an enormous amount of money
over the life-cycle of it's new vehicles. The savings will come from reduced maintenance
costs, reduced coating consumption, and from being able to comply with the latest Clean Air
Act Amendments. Because state air quality regulatory agencies can require Army facilities to
install expensive pollution control equipment if they continue to use the older, higher VOC
materials, the use of E-coat can save money through cost avoidance. At one Army depot
alone, the use of E-coat could save over $3.5 million in one time cost avoidance and over
$196,000/year in subsequent maintenance expenses.
Implementation Low VOC Cleaners at Army Depots.
Corpus Christi Army Depot (CCAD) repairs and reworks Array helicopters. CCAD
had been using a wide range of VOC-based cleaning compounds in the bearing shop and
airframe coating facility. AAPPSO staff worked with CCAD to identify the cleaning process
parameters and develop effective measures of cleanliness for the VOC cleaning operations.
Existing private industry experience was leveraged during the cleaning parameter assessment
The key cleaning parameters were then compared against the performance of currently
available aqueous cleaners. Bases on this analysis, AAPPSO staff identified a non-VOC
based, aqueous cleaner that could satisfy the important cleaning process parameters.
Depot staff developed a performance test program to verify aqueous cleaner system
performance. Two performance test programs were initiated. The first program was designed
to verify that the aqueous cleaning process could be used on high-value bearings without
causing corrosion. The second program was designed to verify that the aqueous cleaner could
remove soils from airframe before final coating application.
Both performance tests program were conducted at the depot using production
personnel. The use of depot personnel and equipment ensured that the aqueous cleaners could
not only satisfy operational requirements, but could also be implemented. Trials were
conducted using the aqueous materials to clean components and airframes. The trials
demonstrated that the aqueous cleaner was an effective substitute for the VOC based
materials.
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The aqueous cleaner based systems have been installed at the depot Although VOC
emission reductions are difficult to quantify, use of the aqueous cleaners has reduced depot
operating costs. Depot personnel estimate that $75,000 is saved every year by avoiding the
costs of purchasing, handling, and treating the hazardous VOC based cleaning materials.
Replacement of Ozone Depleting Compounds
The Army uses a wide range of chlorofluorocarbons (CFCs) in fire suppression,
refrigeration, and solvent cleaning systems. CFCs are considered Ozone Depleting
Compounds (ODCs) because they rise to stratosphere and catalytically destroy ozone
molecules. In 1988, the United States Congress ratified the Montreal Protocol which is
intended to protect the ozone layer by eliminating ODC production. Broadly speaking, the
Montreal Protocol increases taxes on some compounds and eliminates production of all ODCs
in accordance with a fixed time-table. Because the United States, the Department of Defense,
and the Army have accepted the Protocol guidelines, ODCs will have to be removed from
fielded equipment and designed-out of subsequent systems.
Considering that ODCs are mentioned in over 9500 military specifications, reducing or
eliminating the uses for these materials is a technically complex task.1 To manage this task.
AAPPSO consulted with technical experts, industry, and the Chairman of the United Nation's
"Halons Technical Options Committee." Based on these consultations, AAPPSO developed a
"Strategic Plan for Replacing Ozone Depleting Chemicals in U.S. Army Tactical Weapons
Systems." This plan presents solutions for the problems caused by ODCs used as fire fighting
materials, refrigerants, and cleaning solvents.
The ODC plan suggests overall system replacement and existing stock conservation as
the most effective means of addressing the fire fighting issues. Current Array tactical
equipment typically includes hand-held fire extinguishers and an automatic fire suppression
system based on the halon family of chemicals. Hand-held units are used to fight small
electrical or equipment fires. Automatic units are used to extinguish fires caused by
catastrophic accidents or combat damage.
The plan describes a logical process for replacing the halon filled hand-held units with
similar carbon dioxide extinguishers. AAPPSO data reviews and fire analysis calculations
showed that slightly larger capacity, but similar rating, hand-held carbon dioxide filled
extinguishers could effectively fight the same size fires as the current Halon 1301 units. The
AAPPSO intends to remove all Halon 1301 hand-held fire extinguishers from Army tactical
vehicles by the end of 1995 and install the more environmentally friendly carbon dioxide
based units. The Halon 1301 units will then be drained and the fire suppression chemicals
collected in the ODC Reserve.
The Reserve concept is intended to ensure that the Army has enough Halon 1301 to
satisfy its wartime and operational fire suppression requirements. Main battle tanks, armored
personnel carriers, and most other armored vehicles have an automatic Halon 1301 fire
suppression system. These systems trigger automatically when the armor is breached and
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within 250 milliseconds discharge Halon 1301 to extinguish any resulting fires. What makes
these systems Mission Critical is that Halon 1301 is the only material known that can
extinguish the fire and not smother or poison the crew. Israeli data collected during the 1982
invasion of Lebanon showed that their halon system equipped tanks were 50% less likely to
burn after being hit than non-halon equipped vehicles.4 Because fires destroy tanks and kill
crews far more than armor penetrations alone. Halon 1301 systems are considered vital. The
Army plans to stockpile Halon 1301 from hand-held units and from decommissioned systems
to meet operational needs. This Halon 1301 Reserve will only be used during future
conflicts. The stockpile approach minimizes the amount of halon that will have to be
produced and eventually released into the environment while simultaneously providing enough
material to keep these vital systems operational during combat
The strategic plan addresses the refrigeration issue in a similar manner. Refrigeration
systems are used on many modern tactical vehicles to cool electronics, food, medical supplies.
and crews. Because these military cooling requirements are similar to those of the
private/commercial sector, the plan suggests purchasing commercially developed non-ODC
cooling systems in the future. The ODCs from current Array refrigeration systems will be
collected and a one-year operational reserve kept in supply. The reserve materials will then
be used on an as-needed basis to maintain and repair older ODC based cooling systems.
The strategic plan describes the use of alternative technologies to eliminate the need
for ODC based solvent cleaning systems. ODC based cleaning systems are used to remove
soils from delicate parts, flux residues from printed circuit boards, and as "blow-off cleaners
for precision machinery. AAPPSO determined that the ODC applications were not unique
and that there are many currently available alternative cleaning technologies that could be
used to replace ODCs. These cleaning technologies include aqueous washers, supercritical
carbon dioxide systems, sodium bicarbonate blasting, and vacuum degreasing. The AAPPSO
has communicated the need to eliminate ODC based cleaning systems to the Army acquisition
managers. These managers will use AAPPSO supplied contractual documents to prohibit
contractors from using ODC based cleaning systems. In addition, Army depots are
conducting on-site evaluation programs for the new cleaning systems.
Considering that the ODC program is fundamentally administering the recycling of a
material that will no longer be produced, the economic savings (due to the unknown nature of
the future supply/demand interactions for the materials) are difficult to quantify. However.
the plan is not designed to produce economic benefits, it is intended to reduce the threat to
the ozone layer while simultaneously allowing the Array to satisfy vital wartime operational
requirements.
Elimination of Chromate Conversion Coating Applications.
Many of the armored personnel carriers, self propelled howitzers, and transport
systems used by the Army are fabricated from 5000 series aluminum. The Army has been
applying chrornate conversion coatings to this armor grade aluminum as a CARC system
pretreatraem. The chrornate conversion coating uses carcinogenic hexavalent chromium to
produce a pretreatment film that reportedly improves adhesion and reduces underfUm
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corrosion. Red River Army Depot personnel initially thought chromate conversion coatings
could be eliminated from the aluminum armored vehicles they reworked without resulting in
any performance degradation. Depot staff investigated the best commercial practices and the
pretreatmcnt systems used by other services on similar grades of aluminum. This
investigation revealed that commercial industry and the Navy were using more
environmentally acceptable pretreatments - only the Army still required chromates on armor
grade aluminum. Based on this finding, depot staff contacted AAPPSO and requested
assistance with the elimination of this hazardous pretreatment
The AAPPSO tasked OCRC to conduct a detailed technical evaluation of armor grade
aluminum operational performance both with and without the chromate pretreatment. The
technical evaluation was to focus on the "real-world" armored vehicle operating conditions.
The test program included:
1. Long-term natural marine atmosphere exposure testing of CARC coated armor grade
aluminum test panels.
2. Evaluation of both wet and dry coaling adhesion.
3. Examination of how the alternative surface pretreatments affect resistance to Army
alkaline cleaning solutions.
After completing the long-term exposure and laboratory tests, results were summarized
in a final report. The report concluded that the 5000 series aluminum was so inherently
corrosion resistant that the chromate conversion coating did not inhibit underfilm corrosion.
In addition, laboratory testing demonstrated that primer to aluminum adhesion could be
improved by using environmentally acceptable mechanical pretreatments instead of the
chromate materials. Finally, the alkaline cleaner exposure tests indicated that any number of
the alternative pretreatments improved overall system performance relative to the chromated
test panels. These favorable results indicated that chromate conversion coatings could be
eliminated from armor grade aluminum coating processes without degrading in-service
performance.
The favorable technical evaluation program results led to chromate elimination trials at
Red River Army Depot Depot personnel provided a trial vehicle body and assisted with a
non-chromate conversion coating implementation test The on-site implementation test
confirmed that vehicles could be coated by the depot without the chromate material. Figure 1
shows the trial vehicle coated with the standard Army three color camouflage system.
Based on technical data collected during the on-site implementation program, a
specific process control document, tailored to meet the depot's operational needs, was
developed. The document provides the depot staff with the process requirements and quality
control tests that are needed to eliminate the chromate conversion coatings.
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Elimination of chromate conversion coalings from Red River Army Depot will reduce
hazardous waste generation, eliminate a worker health threat, and cut costs. Currently.
chromate conversion coating rinse waters are processed by an industrial waste treatment plant,
generating hazardous sludge wastes. Elimination of the chromate conversion coating will
significantly reduce the waste treatment plant hexavalent chrome burden. The elimination of
chromate conversion coatings from plant operations will alleviate a threat to worker health.
Currently, the chromic acid based material is sprayed by a "moon-suited" worker in a booth.
By eliminating this hazardous pretrcatment, workers in and around the booth will not be
exposed to hexavalent chromium. Finally, eliminating the chromate conversion coatings will
allow the depot to avoid having to upgrade their pollution control equipment This one Army
depot alone could avoid having to spend $4 million on new pollution control equipment and
save an additional $195,000/year in maintenance costs. Upon receipt of Command approval
for the final changes, chromate conversion coatings at Red River Army Depot will be
eliminated. The success of this project would then be exported to other Army production and
maintenance facilities.
CONCLUSIONS
The following conclusions are based on the overall AAPPSO successes:
1. Acquisition pollution prevention programs save money. Total savings and cost
avoidance from the four programs discussed in this paper for the first year are
close to $8,000,000. Additional yearly savings would exceed $500,000.
2. Acquisition pollution prevention programs reduce the need for hazardous
materials and protect the environment
3. Management of essential hazardous materials will prevent pollution and ensure
Army activities continue to have an available supply of these vital materials to
satisfy mission critical needs.
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BIBLIOGRAPHY
1. Headquarters Army Materiel Command. Environmental Office, April 1993.
2. BASF Corporation Technical Presentation, G. Lovell, April 1992.
3. Materiel Developer's Guide for Pollution Prevention. AAPPSO Publication, 1992.
4. The Illustrated History of Tanks, A. Lighlbody, J. Poyer, Publications International,
1989.
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M577 Test Vehicle, Final Coating System
M577 Test Vehicle, Final Coating System
Figure 1 M577 Test Vehicle Without Chromate Conversion Coating
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SESSION 5
ENCOURAGING POLLUTION PREVENTION
PAPERS PRESENTED:
"Pollution Prevention Opportunities in Coatings:
Educating Those Who arc Responsible for This Task"
by
Robert B. Pojasek
GEI Consultants, Inc.
Winchester, Massachusetts
"Economic Incentives to Stimulate the Development and Diffusion of
Low- and No-VOC Coating Technologies"
by
Brian J. Morton
Research Triangle Institute
Center for Economics Research
Research Triangle Park, North Carolina
and
Bruce Madariaga
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina
"Pollution Prevention in the Wood Refinishing Industry"
by
Azita Yazdani
Pollution Prevention International, Inc.
Brea, California
and
Donna Toy-Chen
City of Los Angeles
HTM Office
Los Angeles, California
"The Importance of Product Stewardship and Its Impact on Pollution Prevention"
by
Richard S. Sayad
The Dow Chemical Company
Midland, Michigan
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(The wort: described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
POLLUTION PREVENTION OPPORTUNITIES IN COATINGS:
EDUCATING THOSE WHO ARE RESPONSIBLE FOR THIS TASK
Robert B. Pojasek
GEI Consultants, Inc.
1021 Main Street
Winchester, Massachusetts 01890
INTRODUCTION
Finding substitutes for regulated chemicals is an expensive proposition for the
suppliers. Millions of dollars are spent in researching and development costs to make
compliant chemicals available to customers. On the other side, these chemical users must
spend a large amount of money to qualify the substitute chemical for its intended applica-
tion. It seems that whenever a chemical gets added to yet another regulated list, vendors
and users begin the quest for substitutes. Regulation creates a rather uncertain future
market because it is difficult to predict which chemicals will be added to which lists.
With a new administration in Washington, D.C., there are already new initiatives to
expand the listing of chemicals reportable on the Toxics Release Inventory's Form R.
One way to provide some level of predictability is by the adoption of pollution
prevention practices by a wide range of industrial chemical users. By increasing process
efficiency, users will require lower quantities of chemicals. Perhaps they will be able to
eliminate the use of certain chemicals altogether by finding new materials which do not
need to be cleaned or coated. Chemical companies can then diversify into providing
these new materials to industrial users.
The expeditious move to pollution prevention has started with the formation of the
American Institute for Pollution Prevention. This group, initiated with funding from the
U.S. Environmental Protection Agency (EPA), is an alliance of 27 trade and professional
associations (see Table 1). All the information generated by EPA's pollution prevention
programs is channeled into these associations to reach a broader constituency. The EPA
can also tap the pollution prevention resources of these groups and their membership as
new programs are initiated.
Another means of expediting the adoption of pollution prevention is by making
sure that engineering students have the opportunity to learn about pollution prevention in
a classroom setting. The American Institute for Pollution Prevention has sponsored an
initiative at UCLA to develop a set of pollution prevention homework assignments that
can be utilized in traditional chemical engineering courses. With the assistance of the
American Institute of Chemical Engineers, a member association, these homework assign-
ments were distributed free of charge to any chemical engineering professor who wanted
them. In a related effort, the author has developed a pollution prevention course that can
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be offered at the graduate level in an environmental engineering curriculum. A copy of
the syllabus may be found in the Appendix to this article.
DESCRIPTIVE METHOD FOR POLLUTION PREVENTION
The descriptive method for pollution prevention has evolved over the four years
that this course has been offered. This approach does not use worksheets, questionnaires,
checklists or case histories. These are prescriptive tools. Instead process flow diagrams
are used to map out the means for producing whatever product the facility is responsible
for manufacturing. Process mapping allows the pollution prevention team to determine
the functionality of the operation. It can be seen that one step initiates another which in
turn initiates another until the process has completed its overall function with some type
of product (result). Materials accounting techniques are utilized to track all materials
used and lost from each unit operation. Losses include those to the air, water, solid
wastes, spills/leaks, and accidents (i.e., bad batches, damaged products, fires/explosions,
etc.). Activity-based costing (ABC) is utilized to allocate environmental management
costs to the individual production units from the overhead which is typically spread
evenly across the entire production sequence. In this manner, opportunities occurring in
high ABC units will be explored first. This will help lower the cost of the operation and
the pollution prevention effort will make it more efficient.
Every loss from the production units is an opportunity not to have that loss. In
any manufacturing operation, there will be many opportunities for pollution prevention.
In the prescriptive method, someone must look for opportunities or read about them in
the available case histories or industry-specific studies. However, these approaches are
not self-sustaining because the listing of opportunities is limited. Because the list is large,
it must be screened with a set of criteria specific to the facility under investigation.
Emphasis will be placed on the primary opportunities. Pollution prevention tools such as
cause and effect diagrams, force field analysis, and dendograms are utilized to determine
the root cause of the loss. Brainstorming techniques are used to derive a large number of
alternatives to eliminate the loss. These alternatives are screened using effectiveness,
implementability, and cost criteria derived by the pollution prevention team. If
necessary, a formal feasibility study is performed on the most attractive alternatives.
Some form of financial justification may be necessary to implement the selected
alternative.
The Descriptive Approach is a logical, common-sense method which is nearly
identical to the application of total quality management and just-in-time programs within
the same manufacturing facility. Students with little knowledge of manufacturing tech-
nology can work with an industry to implement such a program after about seven weeks
of the course. They finish the project at the end of the 14 week semester and it counts
for 40 percent of their grade.
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APPLICATION OF APPROACH TO COATINGS
When coatings become highly regulated, the single focus of the firm using them is
to find substitutes. Certainly this is the approach that the chemical companies wish to
pursue themselves, since they make and sell these coatings. Some of the losses of
volatile organics from the application of coatings can be improved by increasing the
transfer efficiency and by other good operating practices surrounding the storage and
handling of the coating medium. Efficiency translates to less coating that can be sold.
Non-VOC coatings are another option but may have other drawbacks such as
poorer drying, use of flammable chemicals (i.e., alcohols), and a variety of other side
effects.
The questions that the Descriptive Approach ask are: Why are you coating in the
first place? Is there a material that can be used that does not need to be coated? Are
there coatings with high transfer efficiencies that use no liquids? The whole idea is to
eliminate the loss from a coating operation, not to substitute one loss for another. More
than likely there are no ready solutions for most coating problems. However, through
continuous improvement, the pollution prevention team should work towards the non-wet
coating or the elimination of the need to coat by changing the base material. Many
manufacturing firms end up reacting to regulations by switching to substitutes at the last
minute. Sometimes these substitutes are more expensive to buy. They are always
expensive to qualify.
If manufacturers practiced pollution prevention, they would be creating a
predictable market for new materials and non-wet coatings. The chemical companies
would diversify to capture this new market in order to cover the decreased demand for
traditional coatings and low-VOC substitute coatings. Manufacturers must train their
engineers to be skilled at pollution prevention techniques. Manufacturers need to see that
new engineers are being trained in pollution prevention technique application. Manufac-
turers must see to it that the chemical suppliers are provided with an incentive to spend
the money that it will take to revolutionize the way we coat materials today. This is an
area where everyone can win.
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TABLE 1 - AIPP MEMBER ASSOCIATIONS
Aerospace Industries Assoc. of America
Air & Waste Management Assoc.
American Petroleum Institute
American Institute of Chemical Engineers
American Academy of Environmental Engineers
American Iron & Steel Institute
American Paper Institute
American Society of Civil Engineers
American Electroplaters & Surface Finishers Society
American Institute of Architects
Chemical Manufacturers Assoc.
Electric Power Research Institute
Health Industries Manufacturers Association
Industrial Designers Society of America
National Agricultural Chemicals Association
National Association of Corrosion Engineers
National Roundtable of State Waste Reduction Programs
Solid Waste Association of North America
U.S. Department of Defense
Water Environmental Federation
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APPENDIX A
POLLUTION PREVENTION SYLLABUS
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Department of Civil/Environmental Engineering
TUFTS UNIVERSITY
CE-194J Pollution Prevention Spring 1993
Instructor: Dr. Robert B. Pojasek
COURSE DESCRIPTION
This course focuses on the interface between manufacturing and the environment.
By manufacturing a product more efficiently, there will be less losses to the environment.
Pollution prevention examines how a manufacturing firm can move away from end-of-the-
pipe pollution controls as the only means of complying with stringent regulations. A
process perspective is necessary to gain an understanding of chemicals use and process
losses. Information presented in the course will provide a basis for developing and
implementing techniques to reduce these losses at the source.
This is a "hands on" course where the student will learn by actually working on a
pollution prevention project. In lieu of a final examination, the student will work in a
small group to evaluate a designated facility which manufacturers paints, adhesives, or
coatings (i.e., the industry classification chosen as the focus for this semester's course).
Together they will prepare process flow diagrams, materials accounting summaries,
description of all of the opportunities for pollution prevention, and a rank ordering of
these opportunities. Each student in the group will then research one of the primary
opportunities, conduct a feasibility study, and make recommendations for implementation.
In order to learn how pollution prevention programs are planned and implemented,
each student will work in another small group to evaluate a designated firm's actual
program. A confidentiality agreement will be negotiated in each case before the work is
commenced. Each program will be evaluated in terms of the culture of that firm and not
by comparing it to other firms' programs. The group will write a report describing the
program and making recommendations to improve it. Each student will prepare an
individual critical review of the program.
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COURSE SCHEDULE
1. January 25, 1993 INTRODUCTION TO POLLUTION PREVENTION
Without dwelling extensively on the terminology and definitional problems that
currently exist in this emerging field, some generic pollution prevention concepts will be
presented. These concepts will include chemical use cycles, the waste management hier-
archy, sustainable development and the theories of loss control. Incentives and dis-
incentives to the use of pollution prevention practices in industry will be examined along
with pressures that have been brought to bear to induce facilities to place these practices
in place. No attempt will be made to examine specific pollution prevention legislation or
regulations.
2. February 1, 1993 MANUFACTURING AND MANAGEMENT
Emphasis in this course is placed on pollution prevention in manufacturing. All
manufacturing categories have commonalities which, when recognized, allow the
pollution prevention practioner to apply the concepts described in the previous section
without regard to the type of firm. Besides examining manufacturing, the manner in
which manufacturing is managed is a key to the successful implementation of pollution
prevention. Analogous management programs (such as total quality management, just-in-
time, and computer integrated manufacturing) will be discussed along with a model for
manufacturing for competitive advantage.
3. February 8, 1993 CORPORATE POLLUTION PREVENTION PROGRAMS
One of the term papers will have the student explore how companies plan, operate,
and sustain pollution prevention programs. An important key to a successful program is
the recognition of the corporate culture. At various levels in the firm, this culture can
vary somewhat depending on whether one looks at die corporate organization, business
units/ divisions, facilities or departments in the facilities. There is also the issue of the
impact of suppliers and customers in formulating a workable program to enhance
competitiveness of the operation. Analogous programs such as total predictive
maintenance will be examined to see how lessons learned will be applicable to pollution
prevention programs.
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4. Feb. 17, 1993 MAPPING A MANUFACTURING PROCESS OR OPERATION
(Wednesday)
Mapping is utilized to help develop a picture of the process or operation being
examined. Resolving the differences between the way different people see the process
and what is actually happening is a valuable activity. A variety of mapping and other
visualization techniques will be evaluated along with analogies to road maps and electrical
schematic diagrams. Using process flow diagrams to help understand process
functionality is at the heart of the descriptive approach to pollution prevention
assessments. A variety of exercises will be utilized to develop suitable map preparation
skills.
5. February 22, 1993 CONDUCTING A FACILITY ASSESSMENT
To conduct a successful pollution prevention assessment one must learn to become
a good EXPLORER. Utilizing prescriptive tools (i.e., checklists, worksheets, and
questionnaires) for conducting assessments have many problems associated with them.
Process flow diagrams and materials accounting must be an important component of the
assessment. The difference between materials accounting and materials balances will be
explained. It is important that the facility assessment identify all the losses from the
operations or process steps. All ancillary and intermittent operations must be identified
and incorporated into the assessment.
6. March 1, 1993 IDEA TOOL BOX
Total quality management and other management programs employ a number of
tools to define and understand the problems as well as to gather information for the
feasibility study. Every loss identified in the assessment is an opportunity not to have the
loss. To describe the opportunity and to qualify which opportunities are most important,
a variety of tools can be utilized. They include: brainstorming, storyboarding, mind
mapping, cause and effect diagrams, Pareto process, root cause analysis and
computerized simulation models. Examples will be utilized from process equipment
cleaning and chemical transfer/mixing operations.
7. March 8, 1993 ANALYZING INFORMATION
An ARTIST takes information gathered from the assessment and draws pictures with
it. Graphical techniques will be utilized to present the data from the above steps. If the
pollution prevention practitioner can utilize the tool box to discover trends and get at the
root cause of the problems, they can begin to derive alternatives for each primary oppor-
tunity and develop the information necessary for screening and evaluation which takes
place in the feasibility study. Above all, one must resist the search for the "right"
answer.
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8. March 15, 1993 THE FEASIBILITY STUDY
Conducting the feasibility study is like being a JUDGE. Considering the specifics
in each case is important. Criteria for screening alternatives will include effectiveness,
implementability and cost. A more detailed analysis of the primary alternatives will
consider engineering, economics and institutional considerations. The need for bench and
pilot testing must be determined at this time. Ail this activity will help establish a
successful implementation program.
-SPRING BREAK
This break provides an opportunity to work on the term papers. Four lectures will be
given over the next two weeks to familiarize the student with the major categories of
alternatives that are often considered in a pollution prevention feasibility study.
9. March 29, 1993 OPERATING PRACTICES/MATERIALS SUBSTITUTION
Good operating practices are often referred to as the "low hanging fruit" of
pollution prevention. These are the easiest alternatives to implement and may often lead
to the largest increments of reduction. Materials substitution is most frequently utilized
by industry to move from listed regulated materials to unlisted materials. There are many
cases where the substitute has either shifted the media into which the loss was transferred
or was later deemed toxic after more detailed tests were conducted. Dematerialization is
another form or materials substitution that will be covered. TERM PAPER ON COMPANY
P2 PROGRAM DUE.
10. April 5, 1993 TECHNOLOGY/RECYCLE-REUSE-RECOVER
Technology can range from equipment modification and process automation to
quantum leaps in the manner in which an item is manufactured. Industrial ecology is a
term used to examine the concept of recycling. There is often an overlap between
recycling and treatment. Each of these considerations occupy a lower status on the waste
management hierarchy covered in die first class. Sham recycling and off-site operations
will be examined along with the practice of waste exchange.
11. April 12, 1993 IMPLEMENTATION
Implementing the primary alternative selected in the feasibility study is often like
being a good WARRIOR. Instead of fighting to get something implemented, teamwork,
program integration and a good feasibility study should help facilitate project and
program implementation.
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12. April 19, 1993 No Class
This break will provide an opportunity to complete the pollution prevention
projects which are DUE at the next class.
13. April 26, 1993 DESIGN FOR X
It is always preferable to design pollution prevention into new processes and
products. The X can stand for the following terms: environment, recyclability,
disassembly, remanufacturability, reliability, durability, waste minimization, etc. These
terms have been in use for a long time and are all related to one another. Life cycle
analysis of products is also an old tool which has taken on new meaning by including
environmental impacts of operations from the extraction of the raw materials to the
ultimate disposition of the final product. This analysis can utilize the descriptive
approach developed in this course and need not be prescriptive. TERM PAPER ON
POLLUTION PREVENTION PROJECTS DUE.
14. May 3, 1993 COURSE WRAP-UP
Each of the important lessons learned about the manufacture of paints, adhesives
and coatings will be utilized to design the coatings manufacturing facility of the future.
COURSE INFORMATION
Textbooks. There are four texts: "A Kick in the Seat of the Pants" by Roger von
Oeck (ISBN 0-06-096024-8 pbk.); "21st Century Manufacturing" by Thomas G. Gunn
(ISBN 0-88730-546-6); "Faculty Pollution Prevention Guide", EPA/600/R-92/088, 1992;
and "Guides to Pollution Prevention-The Paint Manufacturing Industry," EPA/625/7-
90/005, 1990.
Additional reading materials will be handed out each week in class along with the home-
work assignments.
Reserve Reading. There will be materials placed each week in the reserve reading
location of the departmental library. Usually these materials will provide supplementary
information.
Homework. Homework must be completed by the start of each class. All homework
must be TYPED with adequate spacing to make written comments in the class and by the
instructor. It will be discussed in the class and collected with comments written by the
student as a result of the class discussion.
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Grading. Each student will receive a letter grade based on the following components:
1. Pollution Prevention Project-Term Paper =40%
Group Report = 25% of grade
Individual Report = 75% of grade
2. Critical Review of Corporate Program = 30%
Group Report = 33% of grade
Individual Report = 67% of grade
3. Homework: Approx. six assignments = 20%
4. Classroom Participation = 10%
Class Schedule. Each class will begin promptly at 6:30 p.m. on the dates indicated above
and will end at 9 p.m.
Office Hours. Dr. Pojasek will be available one hour before every class, i.e., 5:30 to
6:30 p.m. He is also available by appointment and by telephone during the normal
business day at the following location: GEI Consultants, Inc.; 1021 Main Street;
Winchester, MA 01890 (617) 721-4097 (voice mail). His fax number is (617) 721-4073.
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204
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ECONOMIC INCENTIVES TO STIMULATE THE DEVELOPMENT
AND DIFFUSION OF LOW- AND NO-VOC COATING TECHNOLOGIES
Brian J. Morton
Center for Economics Research
Research Triangle Institute
3040 Comwallts Road
Research Triangle Park, NC 27709
Bruce Madariaga
Cost and Economic Impact Section (MD-13)
Standards Development Branch
Emissions Standards Division
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
INTRODUCTION
In 1970, the year of the first Earth Day, the nation's newspapers carried a powerful image
that symbolized the responsibility of everyone in a mass-consumption society for creating and
solving environmental problems. This icon is the famous Pogo cartoon: "We have met the
enemy and he is us."
With the exception of the regulation of automobiles, national air pollution policy has only
recently addressed the environmental problems that are directly attributable to the use (as distinct
from manufacture) of mass-produced consumer goods. In the Clean Air Act Amendments of
1990, the Congress directed the Environmental Protection Agency to regulate "consumer and
commercial products" to reduce emissions of volatile organic compounds, which are among the
precursors of ground level ozone. Section 183(e)(l)(B) of the Clean Air Act as amended (Clean
Air Act) defines a consumer or commercial product as "any substance, product (including paints,
consumer and commercial products, and solvents), or article (including any container or
packaging) held by any person, the use, consumption, storage, destruction, or decomposition of
which may result in the release of volatile organic compounds." The definition excludes fuels
and fuel additives.
Thus, generally speaking, the environmental purpose of regulation of consumer and
commercial products under the Clean Air Act is to reduce the flow of volatile organic
compounds (VOCs) into the atmosphere from consumption (including storage) and disposal.
Figure 1 shows the dissipative and disposal emissions into the air that would be the target of
Federal regulation, distinguishing them from the production-related emissions that would be
beyond the scope of regulation under Section 183 of the Clean Air Act (as would emissions to
land and water).
Disclaimer This paper was written by Brian J. Morton and Bruce Madariaga in private capacity.
No official support or endorsement by the Environmental Protection Agency is intended or
should be inferred. ___
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Figure 1. Comprehensive Classification of Emissions From Production and Consumption
Source: Adapted from Stigliani, William M. Chemical Emissions from the Processing and Use of Materials: the
Need for an Integrated Emissions Accounting System. Ecological Economics, 2(4):325-341,1990 (Figure 2).
Consumer and commercial products include literally thousands of specific commodities,
including especially paints and other coatings. "Architectural and industrial maintenance
coatings" are one subgroup of these products currently under consideration for regulation by the
Environmental Protection Agency. These coatings are the source of approximately 3% of all
VOC emissions in the nation. A formal negotiation is underway now to develop a Federal rule to
address this important environmental problem. The rule may set a precedent for subsequent
regulations involving consumer and commercial products.
Economic incentives could constitute the regulatory strategy, or one component thereof,
to be promulgated under Section 183(e) of the Clean Air Act "The regulations under this
subsection may include any system or systems of regulation as the Administrator may deem
appropriate, including...economic incentives (including marketable permits and auctions of
emissions rights) concerning the manufacture, processing, distribution, use, consumption, or
disposal of the product" [Section 183(e)(4)]. Regulations developed under Section 183(e) may
be imposed only with respect to manufacturers, processors, wholesale distributors, and importers
but not to retailers and users.
206
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Economic incentives are feasible for regulating VOC emissions from architectural and
industrial maintenance (AIM) coatings. Most important, economic incentives may be the most
desirable type of regulatory strategy because of their potential to achieve emission reductions at
lesser cost than less flexible strategies, and because of their greater potential to promote
environmentally beneficial technological change.
As the nation redoubles its efforts to solve the nearly intractable problem of excessive and
unhealthy levels of ground level ozone, a broad survey of the potential of economic incentives to
reduce VOC emissions from AIM coatings and other coatings is especially timely. This paper
surveys different types of economic incentives and compares them against the following criteria:
environmental effectiveness, promotion of technological progress, economic impacts on coating
manufacturers, and implementation costs.
A conclusion of this paper is that no single economic incentive will always be the best
because the best program depends on policy makers' objectives. Another general conclusion is
that the most helpful definition of the problem of reducing VOC emissions from coatings focuses
not on reducing emissions from existing products but on providing "coating services" with fewer
adverse environmental effects.
SIGNIFICANT CHARACTERISTICS OF VOCS AND OF OZONE
Volatile organic compounds and ozone have specific characteristics that influence the
design of an effective economic incentive. In an airshed, VOCs mix uniformly with nitrogen
oxides to form ozone, one of the main components of urban smog. The characteristic of being
uniformly mixed implies that the concentration of ozone is independent of the location in an
airshed of sources emitting VOCs but dependent on the total amount of VOC emissions in the
airshed. Another significant characteristic of the pollutants is that at current emission rates,
VOCs do not accumulate in the atmosphere from year to year, nor does ozone, and hence injury
to human health and ecosystem health is due not to the historical mass of emissions but from
current emissions. Therefore, cost effective incentives do not need to differentiate among the
locations of sources and receptors in an airshed, and the incentives should target the rate of
current emissions of VOCs.1
BASIC MECHANICS OF ECONOMIC INCENTIVES TO REDUCE VOC EMISSIONS
The basic rationale for using economic incentives to reduce VOC emissions is to bring an
environmental service provided by the troposphere—its capacity to assimilate VOCs—into the
economic system.2 When people release pollutants into the air, they use an environmental
service without, in most cases, paying for the use of this service. While there is no cost, or an
inadequate cost, to the polluter for releasing pollutants, there is a cost to all persons whose health
or well-being is diminished by the resulting decline in air quality. Economic incentives for
pollution control achieve their environmental purpose by increasing the cost of discarding
unwanted byproducts of production or consumption to the environment.
Economic incentives directly or indirectly set the price of the environment's assimilative
capacity. Fee programs may directly set the price: when the fee is charged per unit of emissions,
the fee is the price. Marketable emission permit programs indirectly set the price: the price is
determined by the permit market After obtaining an initial allocation of permits from the
government, permit holders buy and sell permits. These transactions determine the price of a
permit. Because the permit is an entitlement to emit a certain quantity of a pollutant in a given
time period, for example, one ton of SO2 in one year, the permit price is equivalent to the price of
emissions.
207
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We know from observing ordinary markets that an increase in the price of a resource
motivates users of the resource to use less. An increase in the price of gasoline, for example,
motivates some people to reduce driving and others to buy more efficient automobiles. This
example of the effect of a change in price and many similar examples justify the expectation that
an increase in the price of using the environment to dispose of materials will lead polluters to
reduce the emissions for which they are responsible.
Implicit in using the market system for pollution control is another purpose of economic
incentives and another operating principle: by maintaining polluters' flexibility to respond to
regulation, self-interest ensures that the amount of pollution control undertaken by a polluter is
inversely proportional to the costs that the polluter incurs. Polluters will therefore be motivated
to minimize the aggregate expenditure on pollution control.
Figure 2 illustrates the cost-effectiveness of emission fee and transferable emission permit
programs. Two sources initially emit a total of 30 units of pollution. The government intends to
reduce pollution to a total of 15 units. The government may either charge a fee of $500 per unit
of pollutant or allocate 15 permits (one unit of emissions per permit) in some way to the sources.
An emission fee or a permit price of $500 will induce Source 1 to reduce emissions from 15 units
to 5 units. Source 2 reduces emissions from 15 units to 10 units. This allocation of
responsibility for emission reduction minimizes compliance costs. Figure 2 shows that any other
pattern of emission reductions increases total cost. For example, Source 2 would save the
amount indicated by area A if it were to increase emissions by one unit, but Source 1 would
spend A plus B. Theoretically, economic incentives lead to the cost-minimizing pattern of
emission reductions.
Dollars/unit
of emissions
reduced
MC2
MCi
500
Source no. 1
0123456789
15 14 13 12 11 10 9 8 7 6
10 11 12 13 14 15
543210
Source no. 2
Emissions reduced
Figure 2. Cost-Effectiveness of Economic Incentives for Emission Reductions
Source: Adapted from T. H. Tictenberg, Emissions Trading: An Exercise in Reforming Pollution Policy, p. 20.
208
Resources for the Future. Washington, D.C.. 1985.
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REGULATING VOC EMISSIONS VERSUS PROVIDING PRODUCT SERVICES WITH
LESS ENVIRONMENTAL DEGRADATION
The purposes of any regulatory program influence the choice of specific options for the
many elements in the design of a program. A primary purpose of an economic incentive to
reduce VOC emissions from coatings would be to provide incentives for actions leading to the
achievement of a specific reduction in total VOC emissions from the regulated products. It is
important to observe that the achievement of the goal is not a one-time accomplishment but must
be met on a continuous basis, therefore requiring a permanent incentive.
A significant subtlety affecting the objectives for the regulation of VOC emissions from
coatings is the distinction between aiming for reduced emissions from coatings per se and aiming
for reduced emissions from the means used by coating consumers to obtain the services that
coatings provide. This distinction may have important implications for the design of the most
environmentally effective and least expensive regulatory strategy.
The regulation of consumer and commercial products will illustrate. Regulation of
consumer and commercial products under the Clean Air Act shall require "best available
controls" [Section 183(e)(3)(A)J. The Administrator of the EPA, on the basis of "technological
and economic feasibility, health, environmental, and energy impacts," shall determine the desired
degree of emissions reduction that "is achievable through the application of the most effective
equipment, measures, processes, methods, systems or techniques, including chemical
reformulation, product or feedstock substitution, repackaging, and directions for use,
consumption, storage, or disposal" [Section 183(e)( 1)]. Best available controls refer to the
emissions reduction that is determined by following the procedure specified in Section 183(e)(l).
The requirement for best available controls not only establishes the general environmental
goal of regulation, it also establishes a framework for conceptualizing the thrust of regulation.
Specifically, the most important feature of this framework is a focus on each individual type of
consumer and commercial product: interior non-flat paint, exterior non-flat paint, clear wood
preservative, and others.
A liability in the best-available-controls approach is that it encourages a tendency to
overlook the environmental gains that may be available from such indirect means of emission
reduction as substituting surface-coating-free materials for conventional materials. An analogy
to demand-side management in the electricity market is apposite. Electricity itself is not
consumed because it directly provides things that people value but because it is a source of
energy for lighting and heating, which are directly consumed. The distinction between electricity
and the services that electricity provides leads to a recognition that society may be better served
not by imposing high-cost emission control requirements on coal-burning power plants, but by
reducing electricity demand through, for example, policies that increase the efficiency of using
electricity. For similar reasons, the design of regulations to reduce VOC emissions from coatings
should not overlook options for promoting substitute no-VOC technologies.
Obviously, this argument in favor of pollution prevention is a familiar one. Yet the
combination of pollution prevention and economic incentives is a rather unexplored part of the
policy terrain. A survey of economic incentives to reduce VOC emissions and to promote low-
and no-VOC coating technologies will illustrate the pollution prevention opportunities that may
be seized with the use of economic incentives.
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SURVEY AND COMPARISON OF ECONOMIC INCENTIVES TO REDUCE EMISSIONS
AND TO PROMOTE LOWER-VOC COATING TECHNOLOGIES
Economic incentive strategies designed to achieve emission reductions typically work by
directly imposing a cost on the polluter, or the manufacturer of a polluting product, for the
emissions for which he or she is responsible. Policy-makers have many strategies from which to
choose. Further, the choice is complex because multiple criteria are relevant to the choice of
regulatory strategies. The following criteria, although not exhaustive, are among the most
important for economic incentives to reduce VOC emissions from coatings:
• certainty of air emissions reduction,
• probable implementation cost,
• potential for adverse economic impacts on coating manufacturers, and
• potential to promote technological progress.
To facilitate the comparison of regulatory strategies, we use a system of qualitative rankings that
indicates relative performance on a criterion. Therefore, for example, the specific meaning of a
ranking of poor on a criterion may not be indicated precisely, but the difference in performance
between poor and fair is less than the difference between poor and excellent.
A full comparison of regulatory strategies should account for both direct and indirect
effects. Any strategy that serves to increase the cost of employing VOC-containing coatings will
simultaneously stimulate development of lower-VOC technologies such as coating-free surfaces.
For example, coating-free surfaces are substitutes for surfaces that require coating. If the cost of
coatings is increased, the relative coi>i of coating-free surfaces will decrease, and demand and
prices for coating-free surfaces will increase. Higher selling prices for coating-free surfaces will
then stimulate technological developments. Consequently, over time, the indirect effects of VOC
regulation include an increased demand for substitute products and an increased supply of new
substitute products.
The rate of technological innovation is sensitive to the regulatory strategy. Though
command-and-control strategies that increase the cost of producing or consuming high-VOC
coatings will encourage development of low-VOC technologies, economic incentives may be
used to stimulate technological development in a more effective and sustained manner.3
An economic incentive, such as VOC content fees or VOC allowance trading, provides a
continuous incentive for polluters to reduce emissions. Command-and-control strategies, for
example, VOC content limits and mandated technological requirements, provide a one-time
increase in the cost of using high-VOC coatings. After compliance, polluters do not have a
continuing incentive to reduce emissions further. However, polluters who must pay an emission
fee have a continuous incentive to develop technologies to reduce emissions and hence to reduce
fee payments. Similarly, when participating in an emission trading program, polluters have a
continuous incentive to develop emission-reducing technologies in order to sell more or buy
fewer allowances.
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Various fee-based strategies can be employed to increase the private cost of producing or
consuming VOC-containing coatings. Examples of such strategies include:
(1) simple emission fee—constant or variable fee rate per unit of VOC
(2) emission fee with rebates—fee revenues are rebated to manufacturers,
(3) emission fee over VOC threshold—fee is levied only on emissions from products
of which the VOC content exceeds a threshold, and
(4) VOC reduction subsidy—fee paid by government for each unit reduced.
Table 1 summarizes our evaluation of each of the regulatory strategies discussed in this paper.
In the group of strategies labeled as a "simple emission fee," a fee is levied on all
emissions, and, at any point in time, each source faces the same fee rate. A constant fee provides
a diminishing incentive for emission reduction and technological progress if inflation occurs.
Further, as the economy grows and the volume of coating sales increases, emissions will also
increase.
Variable rate fees are essential to forestalling an eventual increase in aggregate emissions
from the regulated products, and even so the level of emissions will be uncertain. A pre-
specified formula can be used to link the fee rate to the level of emissions reduction progress
from some baseline. Although advance notice of the conditions under which the fee will change
does enhance the formation of expectations, one potentially serious disadvantage of this strategy
is planning uncertainty for sources because emissions reduction progress is uncertain and hence
the fee rate will change unpredictably. Planning uncertainty increases the adverse economic
impact on coating manufacturers.
The potential of a simple emission fee to promote technological progress is very goojd,
but the potential for adverse economic impacts on coating manufacturers is high. The certainty
of emissions reduction is fair even with a variable rate fee because of the difficulty of predicting
the short-term responses to a fee, although repeated adjustment of the fee rate will close the gap
between expected and actual reductions. The probable implementation cost is moderate,
reflecting the regulator's need for: product-by-product information on coating sales, VOC
content of each regulated product, laboratory testing of sampled products, and each regulated
source's remittance.
Fee strategies with full or partial rebates are attractive because rebates can reduce
economic impacts on manufacturers. By rebating fee revenues based on market share or any
other criterion unrelated to emissions, incentives to reduce emissions and to develop lower-VOC
technologies can be maintained Incentives for technological diffusion, however, may be
reduced if revenues are rebated A manufacturer that develops a new technology will be more
reluctant to sell an innovation toother manufacturers, because to do so would reduce the latters'
fee payments, resulting in reduced rebates to the manufacturer selling the technology. Because a
manufacturer also could lose its competitive advantage by selling its technology to competitors,
the total incentive for technological diffusion is especially low in a fee program with rebates.
The total incentive for technological change is less in comparison to fee strategies without
rebates. The record-keeping associated with rebates increases the regulator's implementation
costs.
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TABLE 1. RANKING OF REGULATORY STRATEGIES TO REDUCE VOC EMISSIONS FROM SURFACE COATINGS
RELATIVE RANKING
Strategy
Simple Emission Fee
Emission Fee With Rebates
Emission Fee Over VOC Threshold
Emission Reduction Subsidy
^x ' ' ; •• •• " '
•> \"
Allowances
Marketable Allowances
Auctioned Allowances
Cross-Line Averaging
'
Substitute Product Subsidies
Substitute Product Research Grants
Combination Fee or Auction with
Substitute Product Subsidies
Command and Control
(Content Limits or
Technological Requirements)
Potential to
Promote
Technological
Progress
Very Good
Good
Limited
Very Good
Fair
Very Good
Excellent
Fair
Good
Very Good
Best
Poor
Potential for
Adverse Economic
Impacts on Coating
Manufacturers
High
Low
Low to Moderate
None
, ', , ' '
Low to Moderate
Low
High
Low to Moderate
Low
Low
Highest
Moderate to High
Probable
Implementation
Cost
Moderate
Moderate to High
Low to Moderate
Moderate
< '.'. ';.' '' '•/. '<'•;/:;:./ V^l*
Moderate
Moderate to High
High
Moderate
, ^
Moderate
Low
Moderate to High
Low
Certainty of Air
Emissions
Reduction
Fair
Fair
Fair
None
'/ / ' ', ,1
Excellent
Excellent
Excellent
Poor
Fair
Poor
Good or Excellent
Good
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Another strategy to reduce the adverse economic impact on manufacturers from fees
combines an emission fee with a VOC content threshold. A fee would be levied only on
emissions from products of which the VOC content exceeds a specified threshold. Depending on
the threshold, this hybrid strategy is likely to reduce fee payments in comparison to a simple fee
strategy. It may also may reduce administrative costs because only sales and VOC content of
coatings exceeding the VOC threshold need to be monitored. A drawback with this strategy is
that incentives for technological innovation are limited because no incentive would exist for
reducing VOC content below the threshold.
Another pricing strategy that can be employed to reduce emissions from coatings is a per
unit emission reduction subsidy or negative fee. Instead of manufacturers paying a fee for each
unit of VOC emitted, the regulator would pay manufacturers a subsidy for each unit of VOC
reduced below some baseline. This strategy unambiguously benefits manufacturers while
preserving their incentive to reduce emissions. The subsidy would create an opportunity cost of
using VOCs: forgone subsidy receipts. Provided that the rates are equal, an emission reduction
subsidy and an emission fee have the same potential to promote technological progress.
Unfortunately, there are at least two major problems associated with the subsidy
approach. The most obvious problem is one of funding such a program. A less obvious problem
concerns the long run "entry/exit" impacts associated with subsidizing emission reductions.
Subsidies make the subsidized industry more profitable, thus discouraging exit from the industry
and encouraging entry into the industry. Though each manufacturer has an incentive to reduce
emissions, the number of manufacturers could increase. It is entirely possible that aggregate
emissions could increase in the long run (after entry) with an emission reduction subsidy.
Various emission trading strategies can also be employed to increase the private cost of
producing or consuming VOC-con tain ing coatings. Examples of such strategies include:
(5) simple allowances—VOC allowances for each source,
(6) marketable allowances—trading among sources is permitted,
(7) auctioned allowances—the initial allocation of allowances is made via auction, and
(8) cross-line averaging—sales weighted average limits.
As with fee strategies, different emission trading strategies perform differently on the evaluation
criteria. For the group, the cost of implementation is unlikely to be low because the regulator
must keep track of allowance holdings as well as monitor emissions. With the exception of
cross-line averaging, the trading strategies in this list cap aggregate emissions from the regulated
sources. The first three trading strategies offer unmatched certainty of air emissions reduction;
conversely, as explained below, cross-line averaging performs poorly on this criterion.
The simplest trading strategy works by distributing VOC allowances to each source based
on historical emissions, product market share, or some other criterion. Sources choose their own
least cost strategy to reduce VOCs under their "bubble." If the emission constraint implied by
the distribution of allowances is binding, each source will have a fair incentive to develop or
adopt lower-VOC technologies. Lower-VOC technologies generate an internal supply of excess
allowances that may be consumed by new coatings or increased sales of reformulated coatings.
A source's gain from excess allowances is limited because he or she may not sell allowances to
another company. The prohibition on interfirm trading severely limits the incentive for
technological progress.
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Any particular source's incentive for technological innovation and aggregate (industry
wide) control cost savings will be augmented, however, if sources are allowed to exchange (buy
or sell) allowances with other sources. Intcrfirm trading increases flexibility for responding to
the increased private cost of emissions. A source may find that external sources of emission
reductions are cheaper than internal sources. The prospect of selling excess allowances (or
buying fewer allowances) provides a stronger, continuing motivation to invent lower-VOC
technologies. The incentive for technological progress is very good, but not as high as possible
because, as we explain next, the greatest benefit to an innovator occurs when allowances are
auctioned.
The regulator may sell allowances at an auction instead of giving them away.
Theoretically, at an auction, sources immediately obtain the quantity of allowances that allows
them to achieve the cost-minimizing configuration of emission reductions, given current
conditions. Allowances are thus distributed predominantly to sources whose control costs are
high. Auctions avoid the time and transact ion costs associated with trading, and they
immediately establish an obvious market price, which facilitates the evaluation of future
investments in emission reduction.
An auction allowance strategy could also increase the rate of technological progress.
Although the incentive for each individual manufacturer to develop new technologies does not
depend on the method used to distribute allowances, the distribution method does affect the
private gains from diffusion. Under an auctioned allowance strategy, all participants would gain
from the diffusion of low-VOC technologies in order to drive allowance prices down. This gain
from diffusion is absent from allowance strategies in which the regulator gives allowances to
sources. Therefore, the potential of an auction allowance strategy to promote technological
progress is excellent.
A potential problem with an allowance auction is a substantial adverse economic impact
on sources because they must purchase allowances from the regulator. It is possible to devise
revenue-neutral auctions that minimize these impacts.4 In a revenue neutral auction, all
payments for allowances are kept within the industry; in effect, the regulator rebates payments
for allowances. However, these rebates lessen incentives for technological diffusion.
In the context of this paper, cross-line averaging is another emissions trading strategy in
which trades may only occur within a facility or company. ^ A single sales-weighted average
VOC content limit is imposed on each source. Thus each source's total rate of VOC usage or
production is limited. Unlike the emission trading strategies discussed above, cross-line
averaging does not cap aggregate emissions. Each source is given flexibility to use or produce
high-VOC coalings if it compensates with sufficient use or production of low-VOC coatings. If
a source's actual weighted average is binding, the source will have an incentive to develop low-
VOC coatings or employ low-VOC technologies so that high-VOC coatings or technologies can
also be used. Because of the similarity of cross-line averaging and allowances without interfirm
trading, the-potential of averaging strategies to promote technological progress is only fair.
A potentially serious problem with cross-line averaging strategies is that sources may act
opportunistically, defeating the environmental objective of the strategy. For example, sources
may sell inexpensive low-VOC coatings at reduced prices to reduce their sales-weighted average
VOC content. If this were to occur, aggregate emissions could increase. The certainty of
emissions reduction with this strategy is very low.
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All of the above emission fee and emission trading strategies work by increasing the cost
of producing or consuming VOC-containing coatings. Another approach to motivating VOC
reductions is to directly decrease the cost of developing or producing no- or low-VOC substitutes
for coatings. Two such strategies are:
(9) substitute product subsidies and
(10) research grants.
For example, subsidies could be employed to promote the development or sale of
substitutes such as coating-free surfaces. Ideally, the level of substitute product subsidies should
be directly related to expected VOC reductions. Indirect product subsidies are also possible
through tax credits. Lump-sum subsidies such as research grants may be easier to administer,
though they provide less certainty regarding emission reductions. Grants could directly promote
technological innovation and may also encourage technological diffusion if they are made
contingent upon early public disclosure of new developments.
Unlike per unit VOC reduction subsidies, subsidies to promote the development or sale of
coating substitutes (or no-VOC as opposed to low-VOC coatings) avoid entry-exit problems that
could result in long-run emission increases. Increased profitability and entry could not result in
increased emissions if the substitute product emitted zero VOCs. However, the problem of
funding such subsidy and grant strategies would still exist.
Substitute product subsidies and research grants have a good to very good potential to
promote technological progress, but the certainty of emissions reduction is very low because any
improvement occurs solely as a result of technological innovation and diffusion. Any adverse
impact on coating manufacturers will occur as a result of the diffusion of products that reduce the
demand for coatings. Implementation costs are likely to be low to moderate; linking subsidies to
expected VOC reductions is likely to require somewhat extensive economic and engineering
modeling.
One way to fund substitute product subsidies and research grants is to obtain revenues
from an emission fee or an auctioned allowance strategy [(1), (3), and (7)]. Therefore, a
combination strategy may be desirable:
(11) combination emission fee or permit auction with no-VOC product subsidies
Such a combination VOC reduction strategy would provide the maximum incentive to develop
lower-VOC technologies. It may also encourage coating manufacturers to jointly develop and
share low-VOC technologies because technological diffusion would result in lower subsidy
payments to no-VOC competitors such as producers of surface-coating free materials.
Depending on whether the incentive is an emission fee or a marketable emission permit, the
certainty of emissions reduction is good or excellent, respectively. The disadvantages of these
strategies are an especially great likelihood of adverse economic impacts on coating
manufacturers and high implementation costs.
Authority for States to implement a combination strategy such as (11) is granted by the
Clean Air Act Amendments of 1990. Section 182(g)(4)(B) explicitly states that revenues
generated by an economic incentive program may be used to provide incentives to achieve
additional emission reductions and, more specifically, may be used to encourage the
development of lower-polluting solvents and surface coatings.
The last strategy that we evaluate is a command-and-control strategy:
(12) VOC content limit or technological requirement
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Almost all the rewards that innovation and diffusion bring to sources under the other strategies
are absent. Because these gains are minimal, a command-and-control strategy performs
especially poorly in terms of the potential to promote technological progress. Another
disadvantage is the moderate to high economic impact on coating manufacturers; the impact is
potentially substantial because sources do not have flexibility to find the least costly means of
reducing emissions. Implementation costs are probably low because the regulator does not
absolutely need to keep track of emissions for purposes of determining compliance. The
emission reductions that this type of strategy can achieve are certain in the near term, but they
will be eroded in a growing economy.
Table 1 illustrates the numerous tradeoffs that need to be considered when selecting a
regulatory strategy to reduce VOC emissions from surface coatings. The rankings are based on
an "all else equal" principle and will obviously not apply in all cases. Other criteria that are
important, such as consumer and taxpayer impacts and political feasibility, were not assessed for
reasons of brevity.
CONCLUSIONS
Overall, economic incentives provide substantial advantages over command-and-control
strategies to reduce VOC emissions from surface coatings. In general, economic incentives are
superior with respect to minimizing aggregate expenditure on pollution control (i.e., cost-
effectiveness) and promoting technological progress. The potential for adverse economic
impacts on coating manufacturers tends to be lower with economic incentives. Allowance-based
economic incentives are unique for their ability to cap emissions.
Nevertheless, command-and-control strategies may still be preferable if monitoring,
record-keeping, and other implementation activities are significantly less expensive than with
economic incentives. Hence the choice between strategies depends greatly on the size of the
additional implementation costs associated with economic incentives.
The "optimal" economic incentive strategy depends on the policy-makers' objectives. If
stimulating technological progress is considered of most importance, a combination incentive
strategy such as (11) may work best, but this strategy could impose severe impacts on coating
manufacturers. All of the economic incentive strategies examined in this paper lead to more
rapid technological progress than would result from command-and-control strategies, but some
provide more stimulus than others. All of the economic incentive strategies lead to more cost-
effective emission controls than would result from command-and-controi strategies, but some
imply fees, allowance prices, or subsidies to competitors that could severely affect coating
manufacturers. If certainty over reducing air emissions is of most importance, then emission
trading strategies are best. It is therefore essential that policy-makers determine objectives and
priorities before selecting a regulatory strategy.
Finally, in keeping with the pollution prevention approach, a full appraisal of the
desirability of economic incentives includes an examination of the potential for unintended
damages. The hypothetical programs examined in this paper have been narrowly focused on
VOC emissions, but the environmental problems in manufacturing and using coatings are
interdependent. Narrowly defined solutions may be counterproductive when imposed on
complex problems. Intermedia transfers of pollutants could occur if reformulated products are
more prone to off-specification manufacture or have a shorter shelf life. Manufacturers may
reduce VOC content by substituting a noxious solvent or propellant, which could increase health
risks to workers and product users. A coating with reduced VOC content may produce a less
durable film than a higher-VOC formulation, potentially leading to increased emissions over the
life of the substrate. VOC content limits appear to be more prone to these problems than
economic incentives because limits are more likely to constrain manufacturers' product design
options. This may be another reason to prefer economic incentives over less flexible strategies.
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REFERENCES
1. Bohm, Peter and Clifford Russell. Comparative Analysis of Alternative Policy Instruments.
In: Handbook of Resource and Energy Economics, vol. 1, pp. 395-460. A. V. Kneesc and J.
L. Sweeney, eds. Elsevier Science Publishers, Amsterdam, 1985.
2. Freeman, A. Myrick III and Robert H. Haveman. Residuals Charges for Pollution Control:
A Policy Evaluation. Science, 177:322-329, 1972.
3. Milliman, Scott R. and Raymond Prince. Firm Incentives to Promote Technological Change
in Pollution Control. Journal of Environmental Economics and Management, 17:247-265,
1989.
4. Hahn, Robert W. Designing Markets in Transferable Property Rights: A Practioner's Guide.
In: Buying a Better Environment: Cost-Effective Regulation Through Permit Trading, pp.
83-97. Erhard F. Joeres and Martin H. David, eds. University of Wisconsin Press, Madison,
Wisconsin, 1983.
5. Carlin, Alan. The United States Experience with Economic Incentives to Control
Environmental Pollution, p. 5-17. EPA-230-R-92-001, U. S. Environmental Protection
Agency, Washington, D.C., 1992.
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
Pollution Prevention in the Wood Refinishing Industry
By:
Azita Yazdani & Donna Toy-Chen
Pollution Prevention International, Inc. HTM Office, City of Los Angeles
471 W. Lambert Road, Suite 105 City Hall, 3rd floor
Brea CA 92621 Los Angeles CA 90012
Introduction
Pollution Prevention International, Inc. (PPI) under contract to the City of
Los Angeles conducted a pollution prevention study of the wood refinishing
industry. PPI reviewed the common coatings processes and hazardous
material management practices utilized by this industry. PPI evaluated
alternative water-based and low VOC coatings utilized at various facilities.
In addition, PPI conducted a workshop for the City of Los Angeles
refinishing industry users to share the information about the alternative
technologies and new coatings systems application.
Industry Overview
The wood refinishing industry in Los Angeles consists of furniture and
cabinet refinishing, reupholster and repair shops. These shops are engaged
in the repair and refinishing of household and office furniture and fixtures
(both metal and wood), kitchen cabinets and particle boards. Approximately
300 shops in this industry sector are licensed within the City. The majority
of these shops are small companies with three to seven employees. In the
City of Los Angeles, only one shop employed about 60 employees and three
shops employed about 15 employees.
The industry is primarily focused in Los Angeles' furniture district, with most
shops engaged in refinishing and restoration of antiques. About ten percent
of the companies were contacted by PPI to set up site visits and review
operation and practices.
The basic refinishing steps that most of these shops followed are as
following:
1. Remove old finish, using chemical stripping or sanding
2. Sand, stain, (and bleach) the surface
3. Fill the pores
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4. Apply sealer
5. Add transparent or colored film coat
A number of different chemicals are used in any of the above processes.
These may include:
Cleaning: petroleum distillates, alcohol
Stripping: methylene chloride, acetone
Staining: mineral spirits, alcohol, pigments
Painting: toluene, glycol ethers, pigments
Finishing: resins, shellacs, toluene, diisocyanates
Equipment Cleaning: petroleum distillates, 1,1,1-trichloroethylene,
alcohols
Regulatory Requirements
There are a number of regulatory requirements that impact this industry
sector. These are primarily hazardous waste and air quality requirements.
The South Coast Air Quality Management District (SCAQMD) is responsible
for controlling air pollution and attaining federal and state air quality
standards in Southern California. The regulations limit the content of
Volatile Organic Content (VOC) of the coating or the solvents used by these
shops. All refinishers are required to have a permit, whether or not they
operate a paint booth. The annual emissions must also be reported by each
facility.
The SCAQMD Rule 1136 and 1171 are the two major rules that impact
refinishing operations. Rule 1136 limits a facility on the use of high VOC
coatings that are used on wood products. A coating can not be applied
which exceeds the limits in Table 1. The amount of coating used at the
facility must be recorded to demonstrate the quantity of emissions from the
facility.
Proper application equipment is required when applying coatings. SCAQMD
allows for the following applications equipment:
• electrostatic
• flow coat
• dip coat
• high volume, low pressure (HVLP) spray
• paint brush
• hand roller
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Rule 1171 regulates solvent cleaning of application equipment. The rule
states that a cleaning solvent shall not have a VOC content greater than
950 grams per liter of material and a VOC composite partial pressure of 35
mm Hg or less at 20C (68F). Common VOCs found in cleaners are methyl
ethyl ketone and acetone. Cleaning processes allowed by Rule 1171
includes systems that totally enclose cleaning equipment used to flush the
part in a controlled manner. Wipe cleaning and spray cleaning with a
maximum container of 16 fluid ounces are also allowed.
The refinishers have to also comply with the various regulatory requirements
applicable to hazardous waste generators. These requirements are not
discussed in this paper. It should be noted that in California there is no
exemption for small quantity generators, thus these facilities have to comply
with the regulations without regard to all the waste generated, such as
clean-up solvents, contaminated rags and waste paint.
Summary of Site Tours
Six facilities were toured during this study to explore the management
practices and assess regulatory compliance status of each plant. Of these,
four plants were actual refinishing plants. The other two were furniture
manufacturers.
Three of the refinishing plants visited were very small facilities. The users
at these facilities were for the most part not in compliance with the various
regulatory requirements in place. One plant utilized a spray booth without a
permit. This plant, an antique furniture refinisher, was not willing to
disclose many of the management practices it utilized. For example, the
plant generated no hazardous wastes although it engaged in stripping and
coating of various wood, iron, and cement parts. Isopropyl alcohol or
methylene chloride were used for stripping purposes. For the most part, the
chemical was applied on the part, then the coating was scraped off after
some time. The rags utilized by the workers were soaked in water after
use. This water is then illegally disposed down the sewer. The rags were
either reused or disposed in trash. This refinisher had started experimenting
with some water based lacquers. He sealed the part with solvent based
material and then sprayed water based top coatings. This plant also did not
utilize the required application equipment, such as HVLP guns.
The next refinisher engaged in refinishing and refurbishing of old pieces. He
has switched to water based coating, primarily because of the look and
texture that the water based materials gave his work. This facility did not
restore pieces that require the high polished lacquer look, therefore there
was no need to utilize these types of coatings. No chemical stripper was
used at this facility, only mechanical (hand) sanding was done. This user.
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had never managed any of his leftover chemicals or rags as hazardous
waste. He used water to clean application equipment. The water was kept
in a bucket then dumped on the floor to dry out. This refinisher complained
about the SCAQMD requirements and how he did not have time to keep
track of the paint usage records and prepare the reports required.
The other small refinisher visited used both water based and acrylic
material. The facility had a permitted spray booth and he used conventional
guns to coat. He coated a mixture of old and new pieces, thus a variety of
coating materials are used at this shop. He did not manage any waste as
hazardous waste although he generated some thinner from gun cleaning and
other cleanup operations.
The last refinisher visited was a large job shop that engages in refinishing,
painting, and upholstery of office and commercial clients. This facility
employs as many as 75 personnel at times, and complies with the
regulations from both air quality and hazardous wastes. This facility had
experimented with water based material but found that the water based
lacquer chips, causing problems for the customers. Also parts coated with
this material can not be touched-up. The facility had two permitted spray
paint booths which utilized HVLP guns, and used gun cleaning stations to
clean application equipment. Lacquer thinner was primarily used for this
purpose, which is sent for disposal at a cement kiln for resources recovery.
The filters in the booths is also disposed as hazardous wastes. The facility
spent as much as $15,000.00 annually to dispose of hazardous wastes.
This facility also used stripping chemicals which was hauled as hazardous
waste when used and wash thinner (TCA-based) was used to clean
equipment or dilute coatings. This material was reused until no longer
useful.
Two finishers were also visited, one small and one large. The large facility
mass produces furniture using 50 tons of coatings per year. The furniture
was put together, sanded, and finished on an assembly line process. The
fastening and sanding was done by hand power tools. The finishing was
completed on the assembly line, in the open air, with air assisted airless
spray guns. Two applications of clear coat solvent-based lacquer were
applied in most cases, within ten minutes of each other. In one hour, the
piece of furniture was boxed and ready to go.
The second finisher visited produces high quality, custom furniture. It
designs and formulates its own coatings. All of the furniture is also
fabricated at the shop. The furniture is put together, sanded, and then
finished. The finish is applied by HVLP spray guns in a spray booth. The
finish is one thick coat application of an opaque solvent based coating. The
coated piece is then cured for several hours in a "clean room". The results
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are high quality flawless rock hard coatings. This facility uses less than 4
tons of coatings per year.
Study Findings
The majority of the facilities visited were small quantity hazardous materials
users and waste generators and were in violation of basic regulatory
requirements for air quality, hazardous waste, and hazardous materials
management.
Most users were not familiar with the regulatory requirements governing
their industry, and did not have the necessary permits to operate their
business. PPI also found that most of the facilities had problems with
record keeping and calculations that needed to be conducted on a daily
basis to comply with the SCAQMD rules and regulations.
The impact of air quality regulations on the industry is most significant. The
SCAQMD rules are primarily written for larger furniture manufacturing and
coating facilities and the regulatory requirements for smaller users is
cumbersome.
All refinishers except the largest refinishing facility did not meet hazardous
waste management requirements , including hazardous waste disposal,
manifesting, and generator requirements.
Pollution Prevention Techniques and Technologies
As mentioned earlier, the majority of the users participated during the study
had major problems with the application and implementation of the
regulatory requirements. However, the various pollution prevention
techniques were reviewed and discussed during facility visits, so users will
become familiar with the requirements. The following is a summary of the
various pollution prevention opportunities that were identified for this
industry sector.
EQUIPMENT MODIFICATIONS
There are a number of new equipment technologies that can be utilized by
the paint and coating users to reduce paint usage and overspray. One type
of technology that has become widely utilized in recent years is the High
Volume Low Pressure paint gun systems. These systems allow the use of
low pressure airstream at high pressure to propel coating at the transfer
efficiency of 65-95 percent. This type of technology has been widely used
in the wood industry in the recent years.
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ALTERNATIVE COATINGS
There are a number of alternative materials and processes that are used
throughout the wood industry. These coatings are reviewed below:
Waterborne Coatings - Waterborne coatings are used in some sectors of the
wood industry with documented success. This type of coating contains low
VOC so is favored by the air regulatory agencies. The slower drying time is
sometimes a concern for users with high volume production. The water
borne material may also raise some wood surfaces, requiring extra sanding
and preparation steps. Some VOC solvents are normally used in these
formulations, however, the low VOC concentrations is still an advantage
over conventional coatings. Commonly, electrostatic application equipment
is recommended for high volume spray application.
High Solids Coatings - These coatings contain as much as 30 percent
solvent and up to 55 percent solids by volume. Although these coatings are
low in VOC, they have high viscosity and applications with spray equipment
is more difficult. The high solids content of these coatings require high
drying time, resulting in shorter pot life. The application equipment must be
routinely maintained. Paint "Orange" peeling and solvent popping are also
some of the problems of these coatings. The use of these types of coatings
in wood industry is limited.
UV and IR Curable Coatings • These coatings are used in less than 5 percent
of the wood refinishing market due to the cost of the equipment and
limitations for uses such as refinishing. The transfer efficiency of these
coatings is 95 to 98 percent, and they contain no solvent. The
conventional spray equipment can not be used for the application of this
technology.
Study Conclusions
PPI and the City of Los Angeles concluded that small facilities engaged in
this industry sector have to comply with regulations that are too complex
and time-consuming for a small facility. The industry will respond to a
regulatory assistance program that does not prevent these small businesses
from running their day-to-day operations and will assist them in complying
with the maze of regulations. The City of Los Angeles has considered
making the following recommendations to the SCAQMD to assist the
refinishing industry to comply with the requirements:
« Exempt this industry sector from all record keeping and reporting
requirements for air quality regulations;
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Increase transfer of information between industry and developers of
technologies; ar\d
Mobilize industry to interface with regulatory agencies and regulators.
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TABLE 1
Current VOC Emissions Limit
Rulell36 (August 1991)
VOC LIMITS
Grams Per Liter of Coating,
Less Water and Less Exempt Compounds
ON AND AFTER
7/1/94
COATING
Clear topcoats
Filler
High-Solid Stains
Non-glaze
Glaze
Inks
Mold-Seal Coating
Multi-Colored Coaling
Pigmented Coating
Sealer
Strippers
Low-Solids Stains
Toner, or Washcoat
(e/L)
550
500
700
700
500
750
685
600
550
350
480
(Ib/gal)
(4.6)
(4.2)
(5.8)
(5.8)
(4.2)
(6.3)
(5.7)
(5.0)
(4.6)
(2.9)
(4.0)
(g'D
275
500
700
700
500
750
275
275
550
350
480
flb/eal)
(2.3)
(4-2)
(5.8)
(5.8)
(4-2)
(6.3)
(2.3)
(2.3)
(4.6)
(2.9)
(4.0)
ON AND AFTER
7/196
(E/L)
275
275
240
240
500
750
275
275
240
350
120
(Ib'Eal)
(2.3)
(23)
(2.0)
(2.0)
(*-2)
(6.3)
(13)
(2.3)
C.Oj
12.9)
(1.0)
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
The Importance of Product Stewardship and
Its Impact on Pollution Prevention
Richard S. Sayad
The Dow Chemical Company
1320 Waldo Road. Suite 342
Midland, MI 43640
Product Stewardship can be an important factor in helping businesses maintain that their products
are being used safely by workers who handle the products, from the time they are shipped to the time they
are disposed. Committing the time and effort now to a Product Stewardship Program is an essential invest-
ment in the future of our industry.
Experience suggests that many organizations haven't had the opportunity to completely explore the
positive impact Product Stewardship — throughout the whole life cycle of the product — could have on its
business as well as its customers. And they haven't had the opportunity to develop programs with and for
customers. The following information will help explain Product Stewardship throughout the life cycle of the
product, how it works, the responsibilities involved and the benefits.
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THE MEANING OF PRODUCT STEWARDSHIP
Product Stewardship is more than just a program. Most programs have a beginning and an end.
Rather, Product Stewardship is an ongoing process — a continuous activity that is used to: (1) obtain the
proper health, environmental and safety data for our products: (2) evaluate uses and (3) take appropriate
steps to protect human health, safety and the environment. This last statement especially, take appropriate
steps to protect human health, safety and the environment is the correlation between Product
Stewardship and pollution prevention. Pollution is one of the causes leading to an unhealthy environment
and environmental concern. Preventing pollution is an element of Product Stewardship — a way to lake
action to keep the earth safe and healthy for future generations.
Basically, Product Stewardship is an investment of resources, time, and capabilities. It's knowing
the full capability of our products and explaining those capabilities to the users. It's conducting the various
safety tests and providing notification through material safety data sheets and proper labeling. Product
Stewardship is more than a commitment to develop data for the safety of our products and our customers.
It's a commitment to help customers understand our products and how to use them. To work with them so
they can help themselves.
THE RESPONSIBILITY AND COMMITMENTTO PRODUCT STEWARDSHIP
You may be thinking to yourself right now. "I wish it were just a program, never-ending sounds
awfully time consuming — and expensive." Well, you may be right in one respect — it is a major commit-
ment. Should you choose to embark on the path to Product Stewardship, it will become a continuous
process. But over time, you are likely to stop thinking of it as a "never-ending program" and begin seeing
it as a belter way of doing business.
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Who Is Responsible?
The responsibility of Product Stewardship is covered throughout the whole product life-cycle as
explained in the "Codes of Management Practices and Product Life Cycle" chart. This chart is part of a
program called Responsible Care® — the CM A (Chemical Manufacturers Association) initiative developed
to respond to the questions and concerns of the public surrounding our industry. The aim of Responsible
Care is to respond to the public through improved performance in health, safety and environmental quality.
It is not a public relations program, but rather a performance-based program that requires constant interac-
tion with the public, the government, employees, and every other person affected by our industry. While
Product Stewardship is a code in the Responsible Care Program, Product Stewardship is apparent in all the
codes of management practices.
You 11 notice in the chart below that Product Stewardship is considered in each area of the product
life cycle, from design to disposal. That means Product Stewardship responsibility lies with each and every
employee along the life cycle of the product
Codes of Management Practices and Product Life Cycle
CODES OF
MANAGEMENT
PRACTICES
f
INCEPTION
Design Develop
PRODUCT LIFE CYCLE
Manufacture Transport Sell
Use
DlS|K>>C
Community Awareness &
Emergency Response
Process Safety
Distribution
Employee Health
and Safety
Pollution Prevention
Product Stewardship
ii
Product Stewardship requires a total team effort Marketing, Research and Development, Manufac-
turing. Quality Assurance and Distribution all must work together to provide the necessary commitment.
support and resources for the Product Stewardship activities of each product For example. Marketing
furnishes customers and distributors with appropriate information to promote proper handling, use and
storage of products. This information allows employees, customers and distributors to determine use
limitations that may involve human or environmental hazards and to work with producers to address these
issues through modifications to products and their uses.
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Research and Development is responsible for conducting needed tests at each stage of product
development to look for potential hazards. They also develop applications that permit the handling, use and
disposal of products without creating an unacceptable level of risk. By providing information to production.
distribution and marketing—employees, distributors and customers can learn proper product usage. R&D
also re-evaluates the need for additional health, environmental and safety information as technology and
regulations change.
Manufacturing reviews product specifications and assures that the work environment is considered
when plants are designed, operating practices developed, processes changed and employees trained. They
also inform employees about the product's physical make-up and consequences of overexposure. Manufac-
turing is also responsible for obtaining health information on products from suppliers. They furnish contrac-
tors with exposure guidelines, proper handling, use and disposal of products. It's also their job to adhere to
pollution control and industrial hygiene standards and respond to local health and environmental concerns.
Quality Assurance is responsible for exactly that — assuring the quality of products and services
and that the products are well documented and labeled in compliance with regulations. They also audit the
performance of systems and processes to monitor conformance of policies and provide technical assistance
in quality improvement programs.
Distribution determines that appropriate steps are taken to protect persons, property and environ-
ment while products are being transported and stored. They select the proper containers for distribution and
the proper carriers, warehouses and terminals to perform distribution functions.
It's crucial to a good Product Stewardship program that each function of the product life cycle work
together. It is a total team effort to pull together — and basically, it's a commitment among those functions to
help develop the needed data and to work with customers to support the safe use of our products.
Let me give you a good example of commitment to Product Stewardship in a Research & Develop-
ment function. Well call the product steward in this example Carl. A major part of his job is Product Steward-
ship for aJK/l chloride and epichlorohydrin. When Carl was introducing Product Stewardship procedures to
his customers, he ran into an awkward situation. A medium-sized chemical company in the Midwest ordered
its first shipment of alryl chloride and Carl insisted on visiting the customer and inspecting^he safety facili-
ties before the shipment was delivered. Upon inspecting the facilities, it was discovered that the company
didn't have safety showers within 25 feet of the delivery area. The customer promised the showers would be
installed at a later date. But for safety's sake, the product steward insisted that the showers be installed
before the delivery or the shipment would be stopped. Naturally, the customer was angry — at first. Then he
realized that the product steward was putting the safety of his customers before the company's profit He saw
Carl in a whole new light
Let me give you another example of commitment to Product Stewardship and customers. A product
steward introduced his customers to a new innovation called a dry disconnect valve designed for the safe
handling of altyl chloride and epichlorohydrin. When using this valve, only a few drops of the chemical
would be lost from the hose during a tank truck unloading — as opposed to losing as much as a gallon with
some conventional unloading systems. Again, customers were skeptical. They didn't think the valve would
make a difference. After the first "dry run" testing of the valve at an unloading site, those skeptics became
believers — very appreciative believers. This is just one example of how Product Stewardship is a means to
prevent pollution.
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THE BENEFITS OF PRODUCT STEWARDSHIP
Product Stewardship Programs can. if properly organized, protect people and the environment
through pollution prevention, waste reduction and safety procedures. If each employee is dedicated to the
Product Stewardship Program for their products, workers will be safer, chances of exposure and accidents
may decrease and emissions may decrease.
Product Stewardship also helps protect products from misuse. As mentioned earlier, pan of the
program includes proper and specific labeling and handling instructions — and sometimes a trip to the
customer's location to review storage, safety and even disposal facilities. Al! of these are good methods for
preventing not only pollution, but misuse of the product. When products are being used accurately and
according to your Product Stewardship program, chances of liability and exposure to adverse publicity are
greatly reduced.
THE PROVISIONS OF PRODUCT STEWARDSHIP
Product Stewardship can help show an increase in product safety and assessment It promotes
proper use of products and provides adequate and dear warnings that customers should be aware of. If your
company currently has a Product Stewardship program, but it's basically internal, perhaps you may want to
extend it to your customers. This means notifying customers of any new hazard findings either from the
environmental, TOX or use standpoint — and giving customers various forms of information to help them
with product disposal problems. In some cases, it may even mean prohibiting the use of your products in
certain applications.
Customer Support
After customers learn what we're trying to accomplish through Product Stewardship and that it
promotes their safety, we've found them to be overwhelmingly supportive. Customers do read and appreci-
ate the safety and handling information. And they're always looking for information about regulatory and
compliance issues. Regulatory information isn't always easy to understand and customers appreciate the
help in addressing its requirements. Understanding of the regulations allows customers to more easily
incorporate changes into their everyday processes — changes that keep them in regulatory compliance,
prevent pollution and control waste.
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PRODUCT STEWARDS
Ideally, every product manufactured should have a product steward to follow the use and distribu-
tion of that product Product stewards are expected to be experts on the chemicals they are responsible for.
Responsibilities
Product Stewards are also expected to:
• teach others about chemicals
• respond to emergencies
• know and interpret material safety data sheets and labels
• review customer facilities
• give technical information
• know the laws and regulations for their chemicals
• help customers address product handling deficiencies
• evaluate customer uses of the product and consider potential risk
• participate in product safety reviews (PSRs), and
• know and work with resource specialists — TOX, environmental, industrial hygiene
Knowledge Required
It's important that product stewards keep up with significant new information and communicate it to
customers. It's also their responsibility to provide health and safety information on their product That may
mean training internal employees or customers about the product Product stewards need to be aware of the
ongoing evaluation of the use. storage and disposal of products: if there will be future stewardship require-
ments or additions placed on that program. They also must communicate changes in brochures, literature or
technical data sheets, help in the evaluation of the regulatory impact and initiate corrective actions.
In addition, product stewards need to know about the chemical physical and biological properties of
the product They must know the mode of distribution into commerce, whether direct or through a distribu-
tor, and whether it's a mixed shipment Customer storage facilities must be adequate. Product stewards
should know of other materials in storage and their location. It's also important that they know how the
product will be used by the customer. Are the customers considered high- or tow-technology companies?
And what will be needed to help mem use your products safely? What about disposal? How much of the
material is unused? Is it localized or general? If they incinerate, which products? Are there any recycling or
reclamation programs in effect? What programs are available for correct disposal? A product steward must
know answers to aO of these questions to better help employees and the customer.
Customer Assistance
The amount of assistance a product steward may give a customer depends on the sophistication of
the customers and the hazard properties of the product Some product stewards will devote 5% of their
stewardship responsibilities, some will give 25% of their time and some will give 100% of their time. It just
depends on the nature of their product the uses, and the customer base they support.
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Product safety reviews should be an active part of your Product Stewardship program. Each product
should go through a product safety review to ensure that appropriate steps are being taken to protect
employees, public health and the environment The product steward would help organize and conduct the
review process, which includes manufacturing, marketing, legal and toxicology. These reviews can be done
in various stages of product development and, certainly, if an unexpected incident arises or if new data
comes along that affects health and the environment.
A Product Stewardship program can offer customer support and assistance in the form of industrial
hygiene surveys; safety training using literature, posters, usage presentations arid videos; and discussions on
material safety data sheets. You can also provide information on loading and unloading of the product, waste
reduction, reclamation, and disposal and regulatory assistance. All of this information will help your custom-
ers learn to use your products safely and effectively.
At Dow, we've had over 20 years to refine our procedures and support programs. Continuous
improvement is a daily occurrence Your Product Stewardship program doesn't have to be this in-depth. It
can and will develop as your needs grow and as your company sees the benefits from Product Stewardship.
HOW TO ENCOURAGE EMPLOYEES TO COMMIT TO A PRODUCT
STEWARDSHIP PROGRAM
As mentioned, some companies may have Product Stewardship programs in different stages of
development. That's great. The point is, everybody should have some type of a Product Stewardship pro-
gram — for the good of your company, your customers and the environment.
Incorporating a program into your company will help prevent pollution, reduce waste, assist in
regulatory compliance and possibly increase business. But how do you get your employees to buy into it?
After all, the success of a Product Stewardship program relies heavily on employee commitment and partici-
pation. One method we used to get employees interested involves a new waste reduction program called
WRAP — which is an acronym for Waste Reduction Always Pays. WRAP has five goals:
1. reduce waste to the environment
2. recognize excellence
3. enhance waste reduction mentality
4. measure and track progress, and
5. reduce long-term cost.
Each of our manufacturing divisions is responsible for the development and implementation of the
WRAP program within its own operations. This allows each division the flexibility to tailor the program to
specific needs. Each division is also responsible to encourage employees to take a proactive role in reducing
waste and committing to continuous improvement through Product Stewardship. Encouragement methods
used include idea-generating contests, utilization of quality performance techniques, plant waste reduction
reviews, recognition/reward programs and even the development and communication of top ten generator
lists for waste and emissions at a division.
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Waste data — which includes emissions — is collected across all media, by process, at a facility. A
ratio of waste versus production is then calculated to account for production variances. The waste ratio or
index can be tracked and evaluated by each facility. The program flow chart lists the steps taken in the
WRAP process to achieve continuous improvement
I* R () (J R A -M F I. O XV CHAR T
Communicate
i Track IVogress
I and Report
Implement
Actions
Inventory Losses
Identify
Sourcrs
CONTINUOUS
IMPROVEMENT /^/ Priori*»
Establish Goals
Allocate Resources
Each plant is asked to develop an inventory of its waste streams that may affect the air, water or
land. Specific waste streams are identified and researched as to how they are produced by the process. They
are then prioritized for further investigation and action based on volume and toxicity concerns. Tracking
progress is fundamental in monitoring the impact of the plant's efforts. It also allows the facility to communi-
cate its performance to employees and the community.
S'nce 1974, our plants in the U.S. have cut air emissions by more than 85 percent And we continue
to strive for further improvements. Although waste reduction sometimes requires capital improvements such
as new equipment and upgraded facilities — many of the waste reduction projects have ended up saving us
money. We've saved money on feedstock costs, waste treatment and on landfill costs. And in many cases,
we've also increased productivity and improved product quality.
Examples of How WRAP Works
Here are a few examples of how successful our WRAP program has been. In one department for
films, a waste reduction team identified ways to improve the manufacture of barrier films through source
reduction and improved quality control The team made equipment modifications including: modification to a
film winder for operation consistency, which reduced the amount of rejected material; new gauging equip-
ment to minimize thickness variation, which further reduced film rejection; new monitoring equipment to
ensure that the resin is not overheated and therefore unusable; and a new roU-and-trim grinding system was
installed to make pellets out of scrap material The recycled product can be sold to recycle customers. The
results yielded a 400,000 pound a year reduction in materials going to landfills, and a cost savings of $100,000
a year. The addition of the roll grinding system reduced landfill material by 100,000 pounds a year, at a
savings of $30,000 a year.
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At one of our plants, a waste reduction team identified an opportunity to reduce CFC emissions from
the manufacturing of membranes. These membranes are used in water purification systems and other
systems that remove water from substances such as cheese. The team implemented a number of changes
and modifications. Distillation equipment was installed to purify and recover unused liquid CFC from the
process and a carbon absorptive system was installed to collect the CFC vapors, which were then sent back
to the distillation equipment In addition, specialized equipment was installed to remove water from the
recovered CFC so it could be reused. Later, neutralizing and collection tanks were installed to reclaim more
CFC for reuse and existing equipment was upgraded to improve process controls.
CFC Emissions
i 15°
1 120-
^ 120"
4> CA
J
86 87 «» 90
Membrane Production
•«} .
1
I'.
"£ A T , , , , ,
m 4
*• I
ST , .1...
:_!_
86 »7 88 89 90
As a result of these waste reduction steps, the plant reduced the amount of CFC emissions by 87
percent since 1986, saving over $1.6 million. Also, membrane production more than tripled over that same
time period.
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CONCLUSION
The examples I've given are part of our WRAP program, which is part of our Product Stewardship
program. We've been working toward improving our operations for years—and that's basically how the
Product Stewardship program evolved. Product Stewardship has also helped us comply with government
and EPA regulations. For example, through our commitment to Product Stewardship, we were anxious to
participate in the EPA's 33/50 program. The 33/50 program is the EPA's voluntary pollution prevention
initiative to reduce national pollution releases and off-site transfers by 50% in 1995. The interim goal was to
reduce releases by 33% in 1992. With a strong Product Stewardship Program in operation, sometimes we're
in compliance before the regulations are even issued. That's just better for everyone.
To dose, I'd like to emphasize the importance of Product Stewardship to your company, to your
customers and to our earth. If we don't commit now to pollution prevention, waste reduction and recycling
— all aspects of Product Stewardship — then we can expect a more expensive and harsh commitment in the
future. Now is the time to make the investments needed to ensure that future generations will continue to
use our products — safely and effectively.
Experience has shown that customers want to do the right thing. They use safely information and
want to comply with regulations. As suppliers of these products, it's our responsibility to help our customers
understand the regulations and how to comply with them. That's Product Stewardship — an investment of
our resources, our time, and our capabilities in the whole product life cycle. It's knowing the full capability
of our products and explaining those capabilities to the users.
Conferences like the Pollution Prevention Conference give us the opportunity to cooperate, learn
from and work with each other as an industry. We have the opportunity to discuss regulations and compli-
ance so we can take a proactive approach to making our businesses as safe as they can be — for our work-
ers, our customers, our communities and our Environment.
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SESSION 6
INORGANIC COATINGS
PAPERS PRESENTED:
"Long-Term Corrosion Protection with Single-Coat, High-Ratio Zinc Silicate"
by
Parke Schaffer, Jr.
Inorganic Coatings, Inc.
Malvern, Pennsylvania
'Two Surprises from Inorganic Zinc-Rich Silicate Coating
A reactive semiconductor approach to surface protection"
by
C. William Anderson
Marine Environmental Research
Morehead City, North Carolina
"A New Inorganic Coating for Magnesium Alloys with Superior Corrosion Resistance"
by
Alex J. Zozulin
Technology Applications Group, Inc.
Grand Forks, North Dakota
and
Duane E. Bartak
University of Northern Iowa
Cedar Falls, Iowa
"Inorganic Chemistry as an Option for Formulating High Solids,
Low- and Zero-VOC Architectural, and Industrial Maintenance Coatings"
by
Christine Stanley
Raymond E. Foscante
Ameron
Protective Coatings Division
Brea, California
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(The work described in this paper was not funded by the U.S. Environmental
Protection Agency. The contents do not necessarily reflect the views of the Agency
and no official endorsement should be inferred.)
Lone Term Corrosion Protection with Single-Coat High-Ratio Zinc Silicate
Parke Schaffer, Jr. (Inorganic Coating, Inc.)
Today I will be talking about water-based zinc silicate, follow its evolution from the early
1940's to the present; the evolution from post-cure and self-cure products to the no-cure high-
ratio, NASA formula that is available today.
Water-base zinc silicates were first developed back in the 1930's, but the first large
commercial application was in 1942 on the Wyalla pipeline — a 250-mile pipeline stretching from
Wyalla to Morgan in Australia. The pipeline runs through the desert, through salt marshes and
along the coast within a few yards of the ocean. After 48 years of exposure, a single 3 mil coat of
water-base zinc silicate is still protecting the pipe with no sign of breakdown.
That first application of zinc silicate in 1942 had a unique curing process. The product was
applied and then baked at about 450°F to cure out the alkali metal that is present in all silicates.
In the early 1950's, the product was brought to this country and a post-cure acid wash was
developed to cure or neutralize the alkali.
(The following slides detail long term applications of post-cure and self-cure zinc silicates.)
In order to understand how any coating could protect steel permanently, it is important to
understand the basic corrosion process on steel.
•
(The following is a discussion with slides, detailing the corrosion process on steel.)
There are three basic ways to stop corrosion:
1. With organic barrier coatings such as epoxy, urethane, acrylic, vinyl, etc. Barrier coatings
adhere by means of a mechanical bond (vs a chemical bond) and because they are
organic, break down over time.
2. By galvanizing or metalizing with pure zinc metal applied to the steel surface. A pure
zinc coating protects by setting up a new anode/cathode relationship with the steel acting
as the cathode and the zinc sacrificing as the anode. In mild environments this sacrificial
method may last 40 years, however, in an extreme acid rain, road salt or marine environ-
ment, the zinc will sacrifice rapidly. When the zinc is depleted, corrosion will begin.
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3. Or a third means of controlling corrosion is by applying a single coat of water-base zinc
silicate. Both the above principles are at work with zinc silicate since it first acts galvani-
cally or sacrifically and finally becomes a permanent barrier coating. Here's how it
works:
Zinc silicate is 90 percent zinc and 10 percent silicate or liquid glass with the active com-
ponant being SiC^ or silicone dioxide. SiC^ has the unique capability to chemically
complex with metal. The 90 percent zinc content initially sets up the same anode/
cathode relationship as in galvanizing but with one major difference. The zinc oxides
formed by the sacrificing zinc continue to react with the SiC^ while filling the pores in
the porous film. Over time, the oxides form an extremely dense hard coating that ulti-
mately seals off to become a permanent barrier coating. Why permanent? Because the
backbone of the coating is ceramic, or glass ,or SK^, that is chemically bonded
to the iron on the surface (over 2000 PS I). It does not break down over time.
(Many slides — graphics and actual cross sections — will be shown to illustrate all of the
above; other slides will illustrate the self-healing properties of zinc silicates.)
So far, we have seen how generic zinc silicates protect steel and while all zinc silicates work
in the same way, there has been a definite evolution in silicate chemistry that has allowed quality
and production advantages.
In order to understand the evolution from low ratio post-cure and self-cure to high-ratio no-
cure, you must understand the basic chemistry of alkali metal silicates. (Slides will aid in the
following discussion.) Water-base zinc silicates are, very simply, silicate and zinc. And silicate
is liquid glass. The question has been asked many times, "How is it possible to make glass into a
liquid since glass is insoluble?" Chemically, SiC^ and water will not react and might be
illustrated by: SK^ II ^0. However, if you will recall, early in this discussion I mentioned that
SiO2 reacts chemically with metal - so if we can identify a metal that holds or reacts with water,
we could bridge the SiC^ and ^O. The alkali metals, sodium (Na) potassium (K) and lithuim
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(Li), do react with water and Si02. So an alkali metal silicate looks like this, SiO^^O^O •-
the potassium is holding the water and reacting with SiO2 to form a stable liquid glass. That is as
long as the ratio of SiO2 to K2O does not go above 3.75:1.
After application of a standard ratio (3.75:1) zinc silicate, it's the alkali that must be cured
out of the zinc silicate film. The solublizing agent must be removed by one of three curing
methods: high temperature or baking, acid wash port-cure, or long term self-cure. It is this
curing requirement that has kept water-base zinc silicates in a small niche market. In the early
1970's, NASA undertook a program to solve the curing problems and take advantage of the
chemistry's permanent protection.
NASA found a way to raise the ratio from 3.75:1 up to 5.3:1 -- in other words, they found a
way to remove the potassium metal before it goes in the pail, while maintaining the stability of
the high-ratio liquid glass. So the curing process for high-ratio zinc silicate is simply evaporation
of the water. As the water evaporates, the high-ratio film becomes insoluble and extremely hard
and adhesive reaching 1000 PSI pull strength in just two hours.
The high-ratio chemistry now allows the easy application of a water-base zinc silicate
without a post-cure or indeterminate, lengthy self-cure. Additional advantages include:
recoatable with itself for additional millage or easy repair,
self-inspecting over organic contamination;
mudcrack and overspray resistant up to 6-8 mils DFT;
topcoat with epoxy, acrylic, etc. in two hours or less;
zero VOC's, no fire hazard, no toxic chemical waste;
unbeatable economics, both short and long term.
(Following will be slides detailing long term and application case histories which illustrate
the permanence and above advantages.)
The high-ratio zinc silicate NASA formula provides permanent protection with just a single
coat. Permanent protection, coupled with the advantages above, offer short and long term
economics that are beyond comparison with any coating chemistry that has come before. High-
ratio zinc silicate chemistry is destined to become the world standard in corrosion protection for
steel.
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
TWO SURPRISES FROM INORGANIC ZINC-RICH SILICATE COATING
A reactive semiconductor approach to surface protection
C. William Anderson
Marine Environmental Research
P.O. Drawer 767
Morehead City, North Carolina 28557
Introduction
Much of the information we are seeing at this symposium revolves around the utility of Zn rich
coatings. Marine Environmental Research (MER) has been examining these coatings as the material
component in a surface protective system applicable to both marine and land based needs. The non-
material component of this system is electrical. The way these two components interact and the
surprising results are addressed in this paper.
Pushing an object through a fluid seems a simple enough system to model. It is simple until an
attempt is made to do so. Recent Americas Cup races have been decided on the basis of who has the best
modeling software. Military and commercial operations spend a great deal of effort approaching this
problem. In general, the resistance to pushing objects through water can be treated as having two
components: static and frictional. Static resistance is predominantly a function of the shape of the vessel
and is most important at higher velocities (surprise). Frictional resistance is determined largely by the
"roughness" of the vessel hull surfaces. How important this can be is shown in figure 1.
These diagrams show that is possible to quickly require increased fuel burning just to keep the
same speed. Since shipping is based on meeting timetables and not consumption tables, biofouling that
results in an increased roughness of vessel surfaces is a major concern of marine traders. Power
requirements rise, vessel ranges drop and the new limitations hinder commerce and defense. Over the
years, methods have been put forth to keep fouling to a minimum.
Efforts at keeping the hulls clean include scraping and antifouling coatings. The antifouling
coatings have included copper, tar/pitch, coatings with toxic components and coatings that are ablative,
hard or slippery(l). Figure 2 shows this schematically. None of the existing systems are suitable for
large scale commercial applications for reasons of cost, environmental concern or longevity.
Body
Since the interface between any surface and ion containing solution (like seawater) has an
inherently electrochemical character, it made sense to examine an antifouling approach that utilized both
electrical and chemical properties of this interface (see figure 3). William J. Riffe began a series of field
and laboratory experiments combining conducting or ionic coatings and impressed electrical signals.
After a decade of constant experimentation, he had found an incredibly effective antifouling system:
inorganic Zn rich paint and pulsed electrical signals.
The MER antifouling system consists of two components: a Zn rich inorganic coating and an
electrical signal. The Zn rich coating is applied to the surface utilizing common application technology.
A coating thickness of a few mils is sufficient and can be conveniently applied in one or two passes by
a single operator with minimal time between coats. The lack of volatile solvents or other transference
agents reduces the occupational and environmental impact of application. Low Zn leach rates both extend
the useful life and lower environmental concerns while the system is in use. Several of the physical
properties of the inorganic Zn coating component of the MER system are those expected of the coating
itself. The color, hardness and surface smoothness of the coating are just what is expected for
comparable inorganic zinc coatings. The behavior of the coating changes substantially under the influence
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of electrical modulation, though.
The electrochemical component of the MER antifouling system is the non-classical approach to
the antifouling problem. Zn rich inorganic coatings have significant conductivity and can be thought of
as a complex and heterogeneous electrode surface. An applied potential of appropriate value is able to
allow the controlled release of Zn2"1" ions into the solution immediately in contact with the coated
substrate. Milliseconds later, reversing the electrochemical perturbation results in the replating of the
Zn2+ ions as Zn° back in the coating where it originated. Replating efficiencies for metal ions stripped
from 7 micron diameter electrodes (the diameter of the average dust particle in our formulation) in
potential pulse experiments can rise over 99.95% This results in virtually no net loss of Zn to the
surrounding solution, yet allows some Zn ions to be present in the solution just at the surface at intervals
sufficiently frequent to deter barnacle larvae and other species from adhering to the underlying substrate.
This represents a major advance in antifouling technology from cost, application, environmental and
longevity standpoints.
When evaluating the electrical/electrochemical component of this system, several questions
became evident. While the first experiments were able to produce a significant antifouling system, it
wasn't clear what the pertinent electrochemical variables were. If you are trying to optimize a process,
it is reasonable to have a clue about what variables you wish to adjust. A series of experiments were
undertaken to determine if current, charge, potential or frequency were the principal electrical parameters.
The initial suspicion was that the charge placed on the surface of the coated surface was the
principal antifouling action factor. The understanding of the solution-electrode interface given by the
Gouy-Chapman-Stern etc. models revolves around the capacitive and faradaic behavior of the interface
(2). Electrons present on the surface of a conductor with insufficient energy to be transferred to orbitals
on solution species will still attract cations in the solution. These cations then form a layer of charge
adjacent to the conductor. These two layers of charge form a capacitor. Counterions extend further into
the solution. This series of charges and ions is called the electrochemical double layer and gives the
electrode-solution interface many of its observed properties.
The first significant event in the process of attachment of biofoulants to a surface involves a
"glue" protein, a charged polymer produced by fouling organisms. Macromolecular charges play a
significant role in their structure, migration and orientation with respect to other substances.Since ionic
interactions can be critical in the establishment of an attachment of biological species to surfaces, it made
sense to attempt to modulate the charged double-layer in hopes of disrupting the "glue" - surface
attraction, thereby creating a deterrent to biofoulants. The first experiments were conducted with a
current path directed between the vessel hull, through the Zn coating to external anodes, cathodes or the
surrounding ocean. Examination of the current-charge transients for potential pulses showed very small
current passage through the coating and a dominance of capacitive over faradaic charge transfer. That
finding had two implications. Any redox processes that resulted in mass transfer between phases were
minor and the capacitive component of the interface was important.
Upon examining the antifouling mechanism, it became clear that the Zn had profound effects on
larval metabolism (especially on the glue production) in barnacles and that the nature of the applied
electrical pulse sequence changed both antifouling characteristics and the current time transients. Surfaces
coated with the inorganic Zn coating and subjected to a pulsed electrical signal remained largely free from
hard fouling and those few barnacles that were able to attach to the surface were so loosely held that they
could be swept off with a wipe by a hand. The inorganic Zn coating appeared to have some "odd"
capacitive behavior, as well.
By coupling the coating (ca 90% Zn,ZnO and 10% silicate binder) with an electrical pulse,
significant antifouling capability is produced that can last for years in service. The current requirement
for antifouling action is minuscule: 100 foot long vessels require only standard car battery sized supplies,
for example. Vessels, even stationary in the docks, remain largely free of hard fouling for years. Those
few barnacles that do manage to stick are held so loosely that a swipe of the hand will dislodge them.
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A Test
These findings were brought together and tested on a system where fouling was becoming a significant
problem: electrical power plants. Zebra mussels and other biofoulants were beginning to clog even the
huge heat exchanger water supply "pipes". Shut down and cleaning the heat exchangers can be incredibly
costly, upwards of $1 million per day, simply on the basis of lost generating capacity. As a part of a
major study of potential antifouling coatings, Drs. Leitch and Puzzuoli at Ontario Hydro examined the
MER inorganic Zn system (3) and thirteen other coatings for their antifouling characteristics against zebra
mussels. When the MER inorganic Zn system was installed on a set of flags (coupons or panels) near
power plant heat exchanger intakes, protection against zebra mussel biofouling was provided. Two years
later, the remaining intact unit continues to provide protection. MER's inorganic zinc coating system
(both physical and electrical) was the only non-silicone coating demonstrated as effective against the zebra
mussel fouling. The MER system showed only a few percent of the fouling present in the control
experiments. Identical units treated in the same manner in the same study suffered the disconnection of
the electrical signal source. Those units are beginning to show signs of fouling: this is in the field
confirmation that both the coating and the electrical signal are required to give the indicated antifouling
character.
Subsequent experiments showed that it was not required to have the bulk of the current flow go
from inside the supporting structure into the surrounding solution. Simply passing a current through the
underlying conductor structure imparted, antifouling protection to the surface. We believe the mechanism
of action is the same in this configuration, only that current leaked across the interface gives the required
Zn ion.
Tests on small stationary vessels, larger commercial tugs and industrial power plant installations
show the MER inorganic zinc - electrical system to provide effective antifouling for years in the rather
extreme marine environment. But that's not what we want to address here.
There are two competing aspects a new technology: performance and theory. As we all develop
new technologies, we gain experience in the models and theories of that technology's operation. That
normally gives us the idea, based on some theoretical grounds that a particular behavior is possible within
a technology. As we approach the development of the new idea, we have some theoretical basis for our
approach. Before others invest any time, effort or money, the following question is asked: "We see that
there is some theoretical evidence for this technology, but does it actually work in the field?" On the
other hand, and less frequently, we find some interesting technology that we actually observe in the field.
This time, when we try to develop the technology, we are asked: "We see that it does actually work in
the field, but is there some theoretical evidence for this technology?" This is the situation MER was in:
we had an observable process, yet not a clear underlying theoretical basis for its operation. Experiments
were conducted to try to correct this situation.
The nature of the specific experiments conducted is not entirely pertinent to this discussion, but
during the course of examining the antifouling mechanism, two critical observations were made:
1) Zn was the active component in the antifouling action and the electrical signal significantly
prolonged the lifetime of the efficacy of the coating.
2) In some installations, the underlying support for the coating showed substantial structural
integrity, far beyond that expected under the circumstances.
A third piece of evidence came in at the same time: Zinc leach test results. Antifouling agents have been
notoriously harsh on the non-fouling biological systems living near places where marine vessels spent any
significant time. In order to assess the localized potential environmental impact, zinc leach rate tests were
245
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conducted (EPA test SW-846) and showed MER's inorganic zinc coating formulation has a sub-ppm
Zn/day/M2 covered surface leach rate. While this is a thousand-fold lower than that found for the zinc
dust alone, the relatively impervious crosslinked silicate binder should effectively shut down much ion
and solvent movement so the lower zinc leach rate is expected. The incredibly low Zn leach rate, the
structural integrity of the underlying steel matrix and the prolonged lifetime of the antifouling (due to Zn)
action suggested that the MER coating .system would have significant effect as an anticorrosive coating
system. Again, The MER system relies on both a material component (the inorganic Zn coating) and an
electrical component (the electrical signal). Antifouling action was significantly enhanced and prolonged
with the application of the electrical component. Since Zn ions are the active agent, the electrical signal
appears to help retain zinc in the coating.
With some simple calculations, it is possible to predict a useful lifetime for MER's coating
system: at a coverage of 60 microns, 0.5 microns of the Zn would leach into solution per year. That
extrapolates to greater than 100 years. The use of this coating system above the sea, on "dry" land would
only serve to reduce the rate of Zn leaching, stabilize the material part of the system and provide longer
than expected lifetime. In fact, we know that the entire underlaying substructure is not protected until
the last bit of inorganic zinc coating is gone. Localized deterioration may occur. Even so, at this point,
there is likelihood that this coating system (both material and electrical) will provide anticorrosion
protection beyond the lifetime of those applying the coating on the structure. Considering leaching solely,
75-125 year effective lifetime is not out of the question at this point.
And now, the hard part: elucidation of a mechanism of action.
Before continuing, it is useful to examine the current model of corrosion and some attacks that
have proven successful in the slowing of corrosion processes. We will begin with considering the
electrochemical cell and then the corrosion process cell analog. Figure 4 shows a standard
electrochemical cell. The chemical half reactions in the left and right portions of the cell transfer
electrons externally to the solution through a conductor. The anode electrode is the corroding substance
of interest. As metal atoms ionize, the ions are either dissolved in the solution or form ionic surface
compounds on the anode. Figure 5 focuses on the local cathodic region of a metal protected by inorganic
Zn coating. An oxidant, usually water or water related, is reduced at the cathode to form gases (like
Hydrogen) and other charged species. Charge is carried between the two electrodes through the solution
by ionic transport mechanisms to complete the electrical circuit.
Virtually all anticorrosion strategies focus on one area of this complete process. Alloying
strategies address either conductivity within the metal or the electron transfer process at the electrode -
solution interface. Prophylactic insulating coatings attempt to interrupt the interfacial electron transfer
by providing a barrier to reactant approach. Simply keeping the surroundings "dry" can impede the
charge transfer between anode region and cathode region through the surroundings, as well as lowering
the concentration of the reactant at the cathode. Cathodic protection by sacrificial anode "short-circuits"
the process by providing a better route for electrons that eventually show up at the cathode. Every
electron (or two) that doesn't come from the original anode means there is one more substrate metal atom
that didn't oxidize.
Since both antifouling and anticorrosion are within areas where Zn has found some use, we
looked first to models of operation that zinc has clearly exhibited in the past. This lead us to amass a
list of what is NOT going on in this system:
First (and perhaps most important) is that the MER system doesn't appear to function utilizing
zinc as a sacrificial anode. The loss of zinc from the surface matrix is minuscule, as shown by the
leaching tests. Field tests also support this position. We will see more about this later.
Secondly, this system isn't operating by cathodic protection. The magnitude of current - potential
- charge that is employed in this system is microscopic compared to the normal values found in cathodic
protection (4). Typically, tens of mA/square meter are used in cathodic protection of galvanized steel.
246
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MER's system operates on tens of microamps per square meter. In fact, it was in the experimentation
related to assessing cathodic protection as a mechanism that we noticed that the capacitance associated
with the solution - coating interface was not even close to that expected. Higher than expected
capacitance jumped out to us as well as a dependence of capacitance on potential. Differential capacitance
is nothing new but we felt that the variation was larger than we expected.
Thirdly, the system doesn't behave as a simple insulating impervious coating. The measured
resistance through the inorganic zinc coating is too small. A typical 200 micron coating of MER's cured
coating shows a resistivity of around 2 x 103 kilohms-cm. This is way too low to behave as an effective
insulative coating, yet not low enough to be a "good" conductor.
One more aspect of the MER inorganic zinc coating not yet mentioned is the rough physical
composition.
As we examine the materials that comprise the coating, the several percent of the coating that is
NOT zinc metal looms large. The few percent of the matrix that is silicate based will have substantial
network silicate structure after the curing and crosslinking of the coating removes carrier and expelled
reaction product water. The remaining crosslinked network will have largely insulator characteristics (5).
The zinc metal, of course is a reasonable conductor or at least a very good p-type semiconductor and has
found use in chip gate manufacture. It is reasonable to imagine Zn as a gate material in these
applications, since it is viewed as a "p-metal". "p-metals" are those having hole mobility larger than
electron mobility, as measured by the Hall effect. Thus, Zn can be thought of as having the character
of a p-semiconductor (6). Finally, we have the few percent of the "zinc" that is actually zinc oxide. Zinc
oxide in these films is at best, a heterogeneous phase, coating the zinc metal particles. During the
application of the coating, some of the coating will undoubtedly be pushed aside and allow direct Zn-Zn
contact between dust particles, but the particles will largely be coated with oxide of variable composition.
The electrical properties of ZnO are interesting and complex. ZnO will act as a semiconductor with
about a 3.2 eV band gap (7). Dopants or other compositional variations significantly alter the
conductivity of ZnO, allowing resistivities of relatively "pure" ZnO from 1015 to 10"^ ohm-cm (8). This
range spans resistivities of insulator and semiconductor materials. Assessing the electrical behavior
of the MER coating system becomes problematic when we look at the incredibly low currents / charge
needed for anticorrosive protection. The standard models for anticorrosion protection don't do well. The
model we wish to present here is based on interruption of the electron transfer between metal substructure
and the surrounding species. We believe the Zn / ZnO / SiOx structure is behaving like a semiconductor
device, and perhaps more specifically, like a Field Effect Transistor (FET). Perhaps more appropriately,
it behaves like many FETs connected ip several arrangements throughout the coating.
The FET structure
If we look at the model for a FET, and we will use a Junction FET (JFET) to illustrate the point,
we can interpret portions of the coating structure in semiconductor terms. In the JFET case (figure 6),
the charge transfer from the source to the drain must pass through a narrow region of semiconductor near
the gate. As an appropriate potential/charge is placed on the gate, the nearby majority charge carriers
in the channel semiconductor are depleted from the region around the gate. As the depletion region
grows, the crossectional area available for majority charge carriers to move from source to drain drops.
The source-drain current is lowered as the depleted region grows. When enough charge is placed on the
gate, the conduction channel is finally "pinched off" and current flow stops. This is the classic way that
JFETs can behave as switches, interrupting the flow of current from source to drain. Typical common-
source forward transconductance (the relationship between gate control voltage and source-drain current)
for a JFET is 10,000 micromhos. Small voltages control large currents. This effect is at the center of
the use of FETs in amplifiers.
If we view the corrosion current as the source-drain current, then we can imagine controlling the
magnitude of that current by the application of a small voltage/charge on the gate. We can model much
247
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of the JFET from the components of MER's inorganic Zn coating matrix (figures 7 and 8). The cathodic
portion of a corrosion cell would represent the source of electron flow. The redox processes provide Vdi.
This voltage comes from a combination of submetal through coating to the surrounding oxidant or simply
within the coating itself as some Zn metal is sacrificed. These electrons pass through the coating. With
ZnO behaving as the n-type semiconductor, it would be analogous to the channel semiconductor in the
above illustration. Since the typical ZnO layer is only a fraction of a micron thick, the interfacial region
between two "Zn" dust particles would be thin enough to pinch off readily, shutting down charge transfer
through the ZnO. The field drives the charge carrier motion and with a thin ZnO layer, the field for
even a small potential drop will be large.
Since the drain would be the interfacial region between ZnO surface and surrounding oxidant,
addressing the charge transfer through the ZnO layer and not the Zn dust. In fact, the electron transfer
between surface and oxidant will necessarily involve electron travel through the ZnO layer.
Typical FET gate control voltages require 3-5 V to deplete the channel region. In the absence
of leak pathways, the structure can remain depleted for a long time. In a typical MER application, there
will be dozens to hundreds of particle-particle interfaces. There will also be particles that have metal-
metal contact with other particles and base metal due to application force scraping away ZnO on impact.
This means that the overall structure would less be modelled as a single FET, but as a series of FETs,
each connected through a network of other FETs. This type of structure will likely be "leaky", requiring
some redepletion in order to maintain the effect. The critical junctions, though, are those at or near the
surroundings / coating interface. Interpreting the coating in terms of its semiconductor properties does
allow us to address some of the observed anticorrosive action of the MER coating system.
1) Small charges/currents/voltages can control corrosion currents.
2) Cathodic protection need not play a role in this mechanism, yet electrical control is required.
-the oxidation of the Zn in the coating can be very slow, as long as the gates pinch off the current
through the ZnO channels.
•**>•
Up to now, we have not addressed the presence of the silicate binder. The silicate binder need
play no role in this model, but in fact it may contribute significantly. For example, if we include the
(post-curing) silicate network insulating structures, a more appropriate model FET may be the Insulated
Gate FET (IGFET) or the Metal Oxide Semiconductor (MOSFET). In these structures, the gates are
electronically insulated from the substructure channel semiconductor. The depletion mechanism is similar
to that for the JFET, in that a pinch off region lowers the charge movement through an underlying
semiconductor channel. By this model, reducing the corrosion current by a factor of only 5 would extend
the life of the coating by a factor of 5. This, would turn a 8-year inorganic Zn coating into a 40-year coat
lifetime, neglecting non-corrosion deterioration.
Utilizing semiconductor technology as a means to control is not new (9,10), yet the principal
approaches have centered on modifying conduction band energies to inhibit electron transfer and not shut
down current through external depletion of charge carriers. Some experimental evidence does support
a semiconductor model approach to the MER coating anticorrosion system. For example, the pn junction
has an inherent capacitance and that capacitance depends on the potential of the signal impressed across
the junction. In addition, the resistance through these coatings is temperature dependent. At the
temperature rises, the resistivity drops by about 1 % per Kelvin over a range of room temperature to
40°C. Metallic conductor charge transport would show an increase in resistance with temperature.
Semiconductor charge transport shows resistance drops as temperature rises. In fact, ionic charge
transport shows resistance-temperature behavior similar to semiconductors in that respect and we are
beginning experiments to discriminate between these potential mechanisms.
248
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Conclusions
Inorganic zinc coatings are noted for their ease of application, low toxicity and wide applicability
to substrates. MER has found two areas where a combination of inorganic zinc coating and impressed
electrical signal results in significant prophylaxes.
Marine and freshwater antifouling protection is afforded by the MER coating system. The
inorganic zinc coating and electrical signal are both required for optimum performance.
In addition, the MER system can provide anticorrosion protection for an extended period of time.
The mode of action appears to involve the semiconductor nature of Zn/ZnO in the coating.
References:
1. Costlow, J. and Tipper, R., "Marine Biodeterioration: an Interdisciplinary Study", Naval Institute
Press, 1984.
2. Bard, A.J. and Faulkner, Chapter 12 in "Electrochemical Methods", Wiley, 1980.
3. Leitch, E. G. and Puzzuoli, F. V., J. Protective Coatings & Linings, 9, no. 7, 2, 1992.
4. Morgan, J., "Cathodic Protection", 2nd ed., NACE, 1993.
5. Munger, C. G., J. Protective Coatings & Linings, 6, no. 6, 187, 1989.
6. Dunlap, W. C., "Introduction to Semiconductors", p.56, Wiley, 1957.
7. Brown, H. E., "Zinc Oxide Properties and Applications", International Lead Zinc Research
Organization, N.Y., 1986.
8. Seitz.M. & Whitmore,D., Phys. Chem. Solids, 29,1033,1968.
9. Jain, F. C., Technical Report to NADC #N62269/83-66-32008, 1985.
10. Frommet, M., "Passivity of Metals and Semiconductors", Elsevier, 1983.
249
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90
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Factors in Total Resistance
Japanese Destroyer Yudachi
Hull
shape]—
10 12 14 16 18 20 22 24 26
Vessel Speed (Knots)
Loss of Speed
Japanese Destroyer Yudachi
(Initial Speed: 20 knots I
\
x:
50 100 150 200 250 300 350 400
Days out of dock
Cost of Fouling
Increase in Shaft HP to Keep 15 Knots
50 100 150 200 250 300 350 400
Days out of Dock
Figure 1. a) contributions of static and frictional resistance to the total resistance, b) loss of
speed for a vessel kept at constant power as a result of increased fouling c) required power
increase to keep a vessel at a constant speed, rising due to effects of fouling.
250
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larvae
ro
ui
larvae
d
Figure 2. Four approaches to antifouling: a) toxic leaching b) ablative coating c) "hard1
coating and d) the MER system.
-------
NJ
J I I
I 'l .»
I 1 '
I,,'Conductor,,,
o
o o o
- o o
o
o
o
Charged foulant "glue"
_ Macromolecule
° 4
o
o o
Solution +
4-
Figurc 3. A primary event in fouling is the approach of the charged "glue" molecule to the
surface to be settled on.
-------
e- —>
M
M
R O
Anode Cathode
b)
Corroding Substrate
A
e- — >
M
R O
Local
Anode
Region
Local
Cathode
Region
Figure 4. The electrochemical cell model for corrosion, a) a standard electrochemical cell
having separated half-cells b) a segment of a corroding substrate showing localized cells, with
nearby anode and cathode on the same piece of metal. The circuit is completed by the
movement of ions back to the region around the anode.
253
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;;1JL1 V^vCLJL : o Ll:Uo LI Ct LV->
N)
Products
Oxidant
Figure 5. A view of only the local cathode region of a substrate covered with a protective
inorganic Zn showing the path of -current from a nearby anode region and out through the
coating to the oxidant in the surroundings.
-------
JFET Operation
V
SD
(O
tn
ui
GS
Source
e-
V
Drain
n-type
semiconductor
material
Gate(s)
depletion
region
Figure 6. A diagram of the common mode of operation for a junction field effect transistor
(JFET). Depleting the channel region of charge carriers reduces the ability of current to flow
between the source and the drain.
-------
Substrate
IVTetal
cn
Zn:85% by mass ZnO:7%by mass
Silicate binder:8% by mass
(ca. 25 micron coat indicated)
Figure 7. If you were 500 microns tall, what would the surface and coating look like? This
shows the coating a bit more to scale, with oxide layers present on the Zn particles and binder
present. This coating would be about 1 mil thick.
-------
Substrate metal
Source
N)
Ul
ZnO
Drain
Product(s) Oxidaht
Figure 8. Focusing on a single pair of the dust particles in contact with the substrate metal, the
analogous structures to a JFGT appear: the source current comes from the reductant at the
anode, the drain is the oxiclant half reaction and the ZnO forms the n-typc semiconductor
channel between the gates. The externally applied signal provides the field to shut off the
source-drain current.
-------
258
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
A New Inorganic Coating for Magnesium Alloys
with Superior Corrosion Resistance
Alex J. Zozulin
Technology Applications Group, Inc.
4957 10th Avenue South, Grand Forks, ND 58201
Duane E. Bartak
University of Northern Iowa, Department of Chemistry
Cedar Falls, IA 50614
INTRODUCTION
Magnesium, the sixth most abundant element in the earth's crust, is the lightest of all
commonly used structural metals. Having a density of only 1.74 g/cm3, it is one and one-
half times lighter than aluminum, approximately four times lighter than zinc or steel and is
comparable in weight to perhalogenated or mica and asbestos filled plastics. Although pure
magnesium is too soft for structural use, the addition of other elements such as aluminum,
zinc, manganese and rare earths have produced alloys with enhanced chemical and physical
properties. Alloys of magnesium have found considerable use in applications where weight
saving is important. The automotive industry has been looking increasingly towards magne-
sium for reducing vehicle weight, thus improving fuel economy, and is currently the major
user of magnesium die cast parts. For example, a weight reduction of 125 Ib. will yield a
fuel economy improvement of 0.2 to 0.5 miles per gallon in the EPA Combined City-
Highway test.1 In a recent perspective of magnesium in automobiles more than forty pro-
duction applications of magnesium alloys on US cars are listed.2 Other industries which
benefit from magnesium's low weight include power tools, computers, recreational equip-
ment and aerospace. In addition to it's low weight other advantageous properties include a
hjgh-strength-to-weight ratio, excellent dimensional stability, high impact resistance, good
creep strength as well as high thermal and electrical conductivity. In addition, magnesium
and its alloys are recyclable and present no toxicity hazard.3
Pure magnesium metal is a reactive metal and thus is easily oxidized. This oxidation
or corrosion, galvanic as well as surface, is often the major obstacle against the use of mag-
nesium in aggressive corrosive environments. However, through the use of high purity
alloys with a low content of iron, nickel and copper, satisfactory performance may be
achieved with respect to surface corrosion.4-5 For example, the corrosion rate in salt spray
(ASTM B117) of high purity AZ91D6 and AM607, both die cast alloys, range from 1-12
mpy and less than 20 mpy, respectively, while two sand cast alloys, AZ91E and WE43,
exhibit similar rates of 5 mpy8 and 8-16 mpy9, respectively. Other commonly used alloys,
such as ZE41 A, demonstrate considerably higher corrosion rates. The corrosion rate of
ZE41A has been reported to be greater than 400 mpy.10 The utilization of these alloys, par-
ticularly in aggressive environments, will require the application of surface treatments to
provide additional protection against surface corrosion. In contrast, alloy composition will
have a limited influence on galvanic corrosion; however, in this case, the service perfor-
mance will depend on the proper design, assembly and surface treatments as well as the
metal purity.11 25g
-------
In terms of aerospace applications, magnesium alloys, including ZE41 A, QE22A
and AZ91E, are currently used to fabricate main transmission housings and other gear boxes
for several helicopters which are used for commercial and military purposes. Other parts,
which are cast using these alloys, include intakes and intermediate casing for aircraft
engines, housing for auxiliary power units, canopy frames and speed brakes. In many cases,
extremely corrosive environments are encountered and, as a result, high performance coat-
ings are required to produce maximum protection against surface and galvanic corrosion
while minimizing maintenance.
The surface treatment processes for magnesium alloys which serve as a paint base
and a barrier towards corrosion can be grouped into two types. The first type is the chemical
conversion coatings which are applied either by immersion, brush on or spray-type process-
es while the second type involves an electrochemical anodic process. Table I provides a b'st
of the more commonly employed surface treatments.12 Though many of the conversion
coatings do produce a surface that provides some corrosion protection and can act as a paint
base, they are limited in applications on the more reactive sand cast alloys. In addition, the
abrasion resistance of these coatings, including the anodic processes, are not particularly
high. It is interesting to note that most of the treatments shown in Table I also utilize chro-
mates in the primary coating or sealing bath. The utilization of chromates plus other materi-
als such as cadmium, zinc, lead, copper and many volatile organic compounds (VOCs) has
resulted in the EPA identifying the metal finishing industry as one of the most significant
contributors to environmental pollution.13 As a result, there is a critical need for new coating
technologies which will reduce or eliminate chromate based systems yet provide adequate
corrosion resistance, abrasion resistance and paint adhesion.
Table I. Common Inorganic Surface Treatments for Magnesium Alloys.
Chemical Treatment
#1
#7
#17
#19
#21
HAE
Indite No. IS
Bonderile 1000
Conversion
Conversion
Anodic
Conversion
Conversion
Anodic
Conversion
Conversion
Solution Constituents
Sodium dichromate, nitric acid
Sodium dichromate. calcium or magnesium fluoride
Ammonium bifluoride, sodium chromaie,
phosphoric acid
Chromic acid, calcium sulfate
Chromic acid, ferric nitrate, potassium fluoride
Potassium hydroxide, potassium fluoride.
aluminum hydroxide, sodium phosphate.
. potassium manganate
Chromic acid, chloride, nitrate solution
Iron phosphate
Recently, a new high performance coating for magnesium alloys has been developed
which exhibits improved corrosion protection and abrasion resistance as well as providing
an excellent paint base. The coating has been given the trademark, TAGNTTE™, and is pro-
duced by an electrochemical process that does not employ chromates. The process and coat-
ing characteristics arc described herein.
260
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products which may be present on the alloys through the use of the mild alkaline etch. This
solution, commonly used to brighten die cast alloys, shows an insignificant metal loss after a
ten minute treatment. The coating process itself consists of two steps. The first step is a
simple chemical process in which the magnesium alloy is immersed into a heated solution
containing the fluoride ion. This solution applies a layer containing a mixture of magnesium
fluoride and oxofluorides and magnesium oxide and serves as a base for the step second.
The second step is an electrochemical process in which the magnesium alloy is made the
anode in an electrolytic cell.
The electrolytic process is accomplished using a relatively high voltage rectifier
which supplies a combination AC/DC signal to the electrochemical cell. As in other
anodization processes, the magnesium alloy is the anode while the stainless coating tank
serves as the cathode. The electrolytic process involves the concurrent anodization or oxida-
tion of the metal substrate and deposition of inorganic species from the silicate containing
electrolyte. As a result of the relatively high voltages, greater than 150V, a spark process
develops during the deposition. The sparking action is the result of the applied voltage being
greater than the dielectric breakdown voltage of the layer produced in the first chemical step
and the developing coating in the electrolytic step and produces temperatures which have
been estimated to be greater than 1000 C. These localized high temperatures result in the
fusion of silicate and oxide species onto the metal surface. Although the heat generated
from the spark is localized on the surface, the resistive heating of the solution requires a
cooling system to maintain the electrolyte temperature between 10-20 C. Figure 2 is a pho-
tograph of a magnesium AZ91D panel during the deposition process with the sparks visible
on the panel surface. The lifetime of these sparks is typically less than a millisecond.
figure 2. A photograph of • 4" x 6" lest panel of magnesium alloy AZ91D during the Tagniie anodic tpaik
deposition process.
Surface and near surface elemental analysis of the coating by ESCA indicates the
261
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EXPERIMENTAL
Evaluation of coating performances was conducted on two magnesium alloys,
AZ91D, a die cast alloy, and ZE41 A, a sand cast alloy. All panels used to evaluate corrosion
resistance were from the same melt so as to eliminate any variation in base corrosion rate for
the bare metal due to variations in alloy composition. All coatings were applied as per speci-
fications either in-house for the Tagnitc coating or by an aerospace approved metal coating
facility. In addition, all panels were entered into the salt spray chamber together to eliminate
variation in chamber conditions.
Coating thicknesses were measured by an eddy current technique using an EMI
International EM-2000E instrument which was calibrated with two plastic sheets of certified
thickness on an alloy base of similar surface roughness as the panel tested. The arithmetic
average roughness height, R,, was measured using a Sheffield type QE profilometer
amplimeter which was calibrated using a precision reference specimen. Five measurements
were made across the surface of each panel using a 0.03" cut off width and 1.5" piloter
stroke length. The five readings were averaged to yield the R, value. Abrasion resistance
testing were conducted using a Taber Model 5130 abraser using two C-17 abrading wheels
with 1000 grams of load (ASTM D4060). The C-17 wheels were refaced before each test
and after every 1000 cycles using a S-l 1 refacing disk. Results are reported as a Taber Wear
Index (TWI) and number of cycles achieved. Corrosion performance testing was performed
using a Singleton Model 20 corrosion test chamber operating as per ASTM B117. Panel
evaluation was conducted as specified in ASTM D1654, method A and B. Scanning elec-
tron photomicrographs were obtained on a Hitachi S-800 scanning electron microscope.
THE COATING PROCESS
The application of the TAGNTTE coating, as is the case with other coating processes,
requires good cleaning practices such as those specified in MEL-M-3171.14 Typically, the
cleaning procedure shown in the process flow diagram of Figure 1 is sufficient to degrease
and clean the surface. In addition, this method is capable of removing minor corrosion
Figure 1. Process Flow Diagram for TAGNTTE Treatment of Magnesium Alloys.
Dcgreaser, aqueous based
40-50eC, 1-15 min., Rinse
Alkaline Etch
70-80°C, 1-10 min.. Rinse
Fluoride Prcireatment
70-95°C. 5-90 min., Rinse
TAGNITE-8200
10-15°C. Rinse
Surface Neutralization
Post-Treatment
50°C. 30-120 seconds. Rinse
262
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major constituents include magnesium, silicon, oxygen and fluorine for the coating on both
the AZ91D and ZE41A alloys with a very minor quantity of potassium. For the ZE41A
alloy, a minor percentage of cerium was detected, a result of the 1% rare earth composition
of the alloy. The measured bonding energies indicate that the silicon atom is present in the
form of silicate, not as silica, and the fluorine atom exists in its ionic form. This presence of
magnesium in the coating indicates the electrolytic process involve the oxidation of the mag-
nesium alloy substrate with the concurrent spark deposition of silicate and oxide species on
the surface of the magnesium alloy. The oxidation and deposition process also results in a
dimensional change for the magnesium alloy part. Cross-sections of panels which were par-
tially masked, then coated and subsequently examined by SEM indicate that a dimensional
increase of approximately 54% of the coating thickness occurs for the AZ91D alloy as com-
pared to 46% for the ZE41 A. These values are similar to those reported for the other two
anodic processes. For example, chemical treatment 17 and HAE show an increase of
approximately 65 to 75% and 50 to 75%, respectively.15
The thickness of the coating can be varied from two to thirty micrometers by control-
ling the current density and the time of the coating process. Typically, the process is per-
formed at a constant current density in the range of 5 to 15 A/ft* with coating times of 10 to
20 minutes for a five to ten micrometer (0.2 to 0.4 mil, type I) thickness and 45 to 75 min-
utes for a 20 to 25 micrometer (0.8 to 1.0 mil, type H) thickness. The final voltage, though
dependent upon the current density and bath composition, typically ranges from 280 to 320
volts for a type I and 320 to 340 volts for a type II with power requirements of approximate-
ly 0.4 and 1.6 kW hr/ft2, respectively.
COATING MORPHOLOGY
The coating produced during the electrochemical process yields a surface with a
finite amount of porosity. The porosity is a result of the evolution of oxygen gas from the
oxidation of water or hydroxide ion with the concurrent generation of sparks at the surface.
Figure 3 A is a scanning electron photomicrograph representing the top view of a 5 microme-
ter thick Tagnite coating on a AZ91D test panel at a magnification of 2000 while Figure 4A
represents a 22 micrometer thick coating on a ZE41A test panel. The maximum size of the
pores is typically in the range of one to five micrometers for a type I thickness and one to ten
micrometers for a type II thickness with the size dependent on the electrolyte composition,
concentration and the time of coating process. The increase in pore size with coating thick-
ness may be attributed to a similar increase in spark size resulting from a greater dielectric
breakdown voltage as the deposition process proceeds. Though the surface is porous, the
surface texture as measured by profilometer indicates the arithmetic average roughness
height (RJ ranges from 25 to 85 microinches for coatings between 2 to 25 micrometers (0.1
to 1.0 mil) thick. The value of Rm is dependent on the time of deposition or the thickness,
only marginally dependent on the current density or the rate of deposition, and is essentially
independent of the substrate alloy. For example, a coating thickness of 12.5 micrometers
produces a surface with a value of R, from 48 to 53 microinches for current densities
between 3 and 15 A/ft?.
Finally, it should be noted that although the coating has a porous microstrucrure,
263
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Figure 3. Scanning electron photomicrographs: A) top view of the Tagnile coating on AZ91D (200xX B) cross-section view of the Tignile coating on
AZ91D(2000bi).
Figure 4. Scanning electron photomicrographs: A) lop view of (he Tagnhe coating on ZE41A (SOOx), B) crou-iectian view of the Ttgraie coating on
ZE41A(1000xX
264
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cross-sectional views of the coating indicate that the pores do not completely transverse the
coating. Figure 3B and 4B are SEM photomicrographs of cross-sections of the TAGNITE
coatings on the same alloys as shown in Figures 3A and 4A, respectively. As can be seen.
the coating interface with the metal is quite good with no passageways occurring between
the exterior and the base metal. Thus, the coating has the effect of preventing an aggressive
environment from contacting the reactive metal substrate which would result in extensive
corrosion.
CORROSION PROTECTION AND PAINT ADHESION
With the advent of high purity magnesium alloys, the corrosion rate for the base
metal has been significantly reduced as compared to pure magnesium metal. In aggressive
environments, however, additional corrosion protection is required and provided by the
application of surface coatings. In addition, these coatings also serve as a base for painting.
To test for corrosion resistance and paint adhesion, accelerated testing is performed using a
salt spray chamber (ASTM B117). Table III illustrates some representative data for salt
spray testing on the AZ91D and ZE41A alloys which have been treated with the Tagnite,
HAE and chemical treatment 17 coatings. As can be seen, the Tagnite coating provides
increased corrosion protection as compared to HAE and chemical treatment 17. For exam-
ple, the Tagnite coating on AZ91D with a thickness of 5 to 10 micrometers (Type I) yields
an ASTM D1654 (procedure B) rating of 8 after 28 days in salt spray while both HAE and
treatment 17 are rated at 5 after just 14 days. It should be noted that the rating is based on
the percentage of the total surface area that has failed due to corrosion pits, blisters or any
other type of failure present. A rating of 8 represents a 2 to 3% failed area and a 5 denotes
11 to 20% of the area has failed. The best rating is a 10 which corresponds to no failures.
The application of a thicker coating provides improved protection as indicated by a rating of
10 for a Type II Tagnite coating after 28 days in salt spray. The ZE41A alloy also benefits
from a Tagnite coating and» as shown in table m, a type II coating typically gives a rating of
9 on panels exposed to salt spray for 14 days while treatment 17 affords only minor protec-
tion with over 75% of the area having failed (a rating of zero) after only 2 days. It should be
noted that the duration of the corrosion test will be less for the ZE41A alloy than the AZ91D
alloy due to the difference in corrosion rates for the base alloys.
Table ID. ASTM D1654 Ratings en AZ91D Panels Subjected to Salt Spray.
Coatinp/Altov
Tagniiel/AZ91D
Tagniie'/AZ91D
Tagniie1/ZE41A
Dow 17/AZ91D
Dow 17/AZ91D
Dow 17/ZE41A
HAE2/AZ91D
Thickness
Typel
TypcH
TypeH
Type I
TypeD
TypeH
Typel
Time
28 days
28 days
14 days
14 days
14 days
2 days
14 days
Unscribed Area (Procedure B^
8
10
9
5
5
0
5
1 Post-treated using sodium dihydrogen phosphate
2 Post-treated using sodium dichromate and ammonium bifluoride
265
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A comparison of the coating morphologies offers a possible explanation for the
greater effectiveness of the Tagnite coating over HAE and treatment 17 towards corrosion.
Cross-sections and surface examination of the coatings by SEM indicate the pores in the
Tagnite coating are smaller and more uniform in size and distribution as compared to the
other two anodic processes. Further, the Tagnite coating shows considerably fewer intercon-
necting pores which completely transverse the coating to the base metal substrate. In con-
trast, the coating from treatment 17 typically produces the deepest pores with a high degree
of interconnectivity. As a result, the Tagnite coating effectively isolates the magnesium
metal substrate from the corrosive environment.
The corrosion resistance of the magnesium alloys may be further improved by seal-
ing the coatings with paints. In this case, test panels of the AZ91D alloy which were coated
with 10 to 25 micrometers of the Tagnite coating were primed with a melamine polyester
primer and then painted with a thermosetting acrylic enamel top coat. The panels after being
scribed were placed into salt spray for 28 days, with an evaluation of each leg of the scribe
being performed every seven days. The data, shown in Table IV, indicate consistently high
ratings with no corrosion migration under the scribe or corrosion in the unscribed areas.- The
lack of corrosion creepage from scribe is indicative of the good paint adhesion characteris-
tics of the coating and may be attributed to its surface morphology.
Table IV. ASTM D1654 Ratings on AZ91D Panels wiih Tagnite, Painted and Scribed.1
Scribed Area (Procedure A> Unscribed Area (Procedure B")
7 day 14 day 2|day. 28 day 28dav
10-22-3 10 10 10 10 10
10-23-3 10 10 10 10 10
10-24-1 9 10 10 10 10
10-25-2 9 10 10 10 10
10-29-6 10 10 10 10 9
1 Testing (ASTM) and evaluation (ASTM D1654) was carried out by R.W. Munay. The Dow Chemical Company,
Technical Service and Development, Lake Jackson Center. Texas.
The effect of primer and top coat on the corrosion resistance and paint adhesion was
also examined on the ZE41 A alloy. When panels of this alloy, treated with the Tagnite and
treatment 17 coatings, are painted with one coat of primer (MIL-M-23377E) and subjected
to salt spray for 28 days, extensive corrosion occurs for the treatment 17 coated panels with
typical ratings of 3 (procedure B). In contrast, the Tagnite coated panels arc rated as 10 (pro-
cedure B). Additionally, panels were also coated with the Tagnite and treatment 17 coatings,
painted with one coat of primer (MIL-M-23377E) and a top coat (MEL-C-46168D). In this
case, the paint adhesion characteristics were tested by scribing the panels before placing
them together in salt spray for 28 days. Due to the higher corrosion rate of this alloy, corro-
sion pits develop on the scribe for both coating systems; however, the extent of corrosion
migration under the scribe or the degree of paint adhesion to the anodic coatings is consider-
ably better with the Tagnite coating than with treatment 17. Ratings (procedure A) of 5 A
and 9A (with a single low value of 7 A) are typically obtained for treatment 17 and Tagnite
coatings, respectively.
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ABRASION RESISTANCE
Abrasion resistance has been determined on Tagnite, treatment 17 and HAE coatings
on AZ91D as well as the Tagnite coating on ZE41 A. Table V illustrates representative data
in the form of the number of cycles and a Taber Wear Index (TWI). As can been seen from
the data, the Tagnite coating on both AZ91D and ZE41A is considerably more wear resistant
than either HAE or treatment 17. Though the abrasion resistance will largely be dependent
Table V. Abrasion Test Results.
Sample TWI-1-
AZ91D. TAGNITE, 0.3 mil 9
AZ91D. TAGNTTE, 0.6 mil 8
AZ91D, TAGNITE. 0.8 mil 7
AZ91D. TAGNITE, 0.9 mil 6
AZ91 D. HAE, Type I (0.2 mil) 142
AZ91D. HAE, Type II (2.6 mil) 142
TEA 1 A, TAGNITE. 02 mil 6
ZE41 A. TAGNITE. 0.5 mil 7
ZE41 A, TAGNITE. 0.6 mil 14
ZE41 A, TAGNITE. 0.8 mil 12
ZE41 A, TAGNTTE, 1.0 mil 14
AZ91 D. TAGNITE, 0.5 mil 14
AZ91 D. Treatment 17.1.0 mil 37
AZ91D.HAE. 1.0 mil 104
Cycle Comments
5000 < 10% metal exposed
7000 < 10% metal exposed
5000 < 10% metal exposed
6000 < 10% metal exposed
75 10% metal exposed, coating gone after 200 cycles
1800 10% metal exposed; coating gone after 3000 cycles
1000 10% metal exposed
5000 10% metal exposed
5000 10% metal exposed
7000 10% metal exposed
9000 10% metal exposed
3000 bare metal starting to show2
1000 coating gone after 500 cycles2
1000 coating gone after 500 cycles2
1 Taber Wear Index (TWI) defined as TWl=(A-B)x 1OOCVC where A is the weight of the test specimen before abrasion in
milligrams, B is the weight of the test specimen after abrasion in milligram and C is the number of cycles of abrasion
recorded.
2 Data provided by R.W. Murray. The Dow Chemical Company, Lake Jackson Research Center, Freeport, Texas.
upon the chemical nature of the coating, the significant increase in resistance may be partial-
ly attributed to the coating process in which the localized high temperature, occurring during
the spark deposition, fuses the silicate and oxide species onto the metal substrate surface.
ENVIRONMENT
Over the last several years, concern has been raised regarding the impact the metal
finishing industry has on the environment. When one considers that the commonly used
materials include chromium, cadmium, zinc, lead, copper, nickel, cyanides and VOCs, it is
not surprising that the EPA has listed the metal finishing industry as a major contributor to
environment pollution.13 Due to the demanding environment in which their products func-
tion, the aerospace industry has become a major user of metal finishing systems, and have
recently expressed concerns regarding VOC emissions, utilization of 1,1,1-trichloroethane,
hexavalent chromium emissions, the land ban and hazardous waste disposal costs, OSHA
267
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compliance and source reduction and recycling. As a result of the increasing inevitable gov-
ernment regulation of hazardous wastes, the industry will be required to become more envi-
ronmentally responsible through the implementation of waste minimization programs and/or
the utilization of less hazardous materials.
Chromates are one of the principal chemicals used in metal finishing industry, partic-
ularly those dealing with magnesium based alloys. The chromate ion is an excellent corro-
sion inhibitor. It is used as a paint pigment, employed in chromate conversion coatings, as
well as in anodizing baths for aluminum based and magnesium based alloys and as a post-
treatment for sealing anodized surfaces. However, chromates are known to be highly toxic
and carcinogenic.16 The oral ingestion of 1-2 grams of chromic acid or 6-8 grams of potassi-
um dichromate is reported to cause kidney failure, liver damage, blood disorders and even
death.17 In addition, exposure of chromates to the skin for prolong periods may cause rash-
es, blisters and ulcers while inhalation may cause lung cancer. Due to these health risks,
OSHA limits insoluble chromates in the air space to lmg/m3 per 8 hour day per 40 hour
week and has specified that chromate containing paints must be labelled with a lung cancer
warning.18
There are several approaches to the chromium issue. One option is to improve the
handling procedures in the work place so as to comply with the allowable chromate expo-
sure limits. Since it is likely that the regulations will only become more restrictive, this alter-
native will serve only as a temporary basis. Another alternative is to reduce or eliminate
chromate containing waste by the application of new technologies. For example, a study by
VanCleave19 has resulted in a significant chromium reduction in which chemical treatment
21 was found to be a suitable replacement for treatment 1, both chromate containing solu-
tions, thus permitting the elimination of a planned 7600 gallon treatment 1 tank in their new
finishing facility.
Though the implementation of chromium reduction programs is clearly needed, the
best alternative is the utilization of chromium free materials. Recently, Hinton20-21 has pre-
sented several alternatives to chromate conversion coatings and paint pigments for alu-
minum based alloys. For magnesium alloy users the elimination of chromate may be more
difficult, partly due to the greater chemical reactivity of magnesium. Many of the commonly
employed conversion coatings are chromate based (see Table I) while the common cleaning
solution for removing corrosion products and old finishes is chromic acid. Further, current
specifications such as MIL-M-3171 require the application of chemical treatment 1 to sand
cast magnesium alloys for corrosion protection during shipment and storage.
As discussed earlier chemical treatment 17 and HAE are routinely applied to magne-
sium alloys when increased corrosion protection is required. Treatment 17 contains approxi-
mately 8% by weight sodium dichromate and, although it is reported that the solution is only
infrequently disposed, thus generating only small volumes of chromium containing waste
water through dragout, the presence of large processing tanks still results in employee expo-
sure and the potential for environmental damage should a spill occur. In addition, even
though disposal is infrequent, chromium is introduced directly into the environment from the
coating itself. Based on the operational parameters for treatment 17 approximately 0.1 to 0.2
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oz of chromium would be introduced into the environment per square foot of metal coated.22
Although HAE is not a chromate containing solution, the coating requires a post-treatment
in ammonium bifluoride and sodium dichromate for all grades except grade 115 and thus uti-
lizes chromium compounds in the overall process.
A significant chromate reduction may be made by first replacing chromate conver-
sion coatings which are used for temporary protection with oil. It has been reported that
magnesium components may be stored from 1 to 5 years if the alloy is oiled and sealed in a
polythene bag containing a desiccant.23 Furthermore, the use of oil instead of the conversion
coatings will allow the metal surface to be cleaned using alkaline cleaners without relying on
chromic acid. Finally, the application of a chromium free coating system such as the Tagnite
coating will eliminate chromates in the anodizing and/or post-treatment baths.
CONCLUSIONS
Reduction and elimination of chromium based systems will be a major endeavor in
the metal finishing industry as the governmental regulation of chromium becomes more and
more restrictive. For magnesium based alloys chromium reduction may be achieved by
replacing the conversion coating used for temporary storage with oil and by the application
of chromium free coating systems such as Tagnite. The Tagnite system provides greater cor-
rosion protection, enhanced paint adhesion and better abrasion resistance than either chemi-
cal treatment 17 or HAE.
ACKNOWLEDGEMENTS
We wish to thank The Dow Chemical Company, Lake Jackson Research Center for
tests conducted on the Tagnite coating as well as Tom VanCleave and Gunter P. Barth of
Lockheed Missiles and Space Company for the ESCA data. We also wish to thank Jim Suda
for performing the SEM work.
REFERENCES
1. Davis, J. The Potential for Vehicle Weight Reduction Using Magnesium, Society of
Automatic Engineers, Paper 910551, 11991. pp. 71-85.
2. Mezoff, J. G. Magnesium in Automobiles, in Perspective, Society of Automotive
Engineers, Paper 800417,1980. pp. 1-14.
3. Murray, R. W., and J. E. Hillis. Magnesium Finishing: Chemical Treatment and
Coating Practices, SAE, Paper 900791,1990. pp. 1-10.
4. Aume, T.K. Minimizing Base Metal Corrosion on Magnesium Products. The Effect
of Element Distribution (Structures) on Corrosion Behavior, Proceedings of the 40th
World Magnesium Conference, Toronto, 1983.
5. Hillis, J.E. The Effects of Heavy Metal Contamination on Magnesium Corrosion
269
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Performance, SAE, Paper 830523,1983. pp. 1-7.
6. Reichek, K.N., KJ. Clark, and I.E. Hillis. Controlling the Salt Water Corrosion
Performance of Magnesium AZ91 Alloy, SAE, Paper 850417,1985.
7. Hillis, J.E. and Reichek, K.N. High Purity Magnesium AM60 Alloy: The Critical
Containment Limits and the Salt Water Corrosion Performance, SAE, Paper 860288,
1986, pp. 1-8.
8. The Dow Chemical Company. Heat Treating Sand and Permanent Mold Magnesium
Castings. No. 141-552-87. Midland, Michigan, 1987. 10pp.
9. Magnesium Elektron, Inc. WE43 A Corrosion Resistant Magnesium Casting Alloy
for Use up to 570°F. No. 467A. Lakehurst, New Jersey, 1991. 4 pp.
10. Stevenson, A. Metals J., 39 (5): 16-19, 1987.
11. Hawke, D.L., J.E. Hillis, and W. Unsworth. Preventive Practices for Controlling the
Galvanic Corrosion of Magnesium Alloys, IMA Technical Committee Report, 1988.
12. The Dow Chemical Company. Magnesium : Operations in Magnesium Finishing.
No. 141-479-86R. Midland. Michigan, 1990. 56pp.
13. Holmes, J. Metal Finishing, 87 (11): 65,1989.
14. Military Specification. MIL-M-3171C. Magnesium Alloy, Processes for
Pretreatment and Prevention of Corrosion on, U.S. Government Printing Office, No.
713-153/4659, March 1974. 44 pp.
15. Military Specification. MIL-M-45202C. Magnesium Alloys, Anodic Treatment of,
U.S. Government Printing Office, No. 703-023/2048, April 1981. 31 pp.
16. McCoy, DJ. Proc. Second AESF/EPA Chromium Colloquium. Miami, Florida,
1990.
17. Toxicological Profile for Chromium, Agency for Toxic Substances. U.S. Public
Health Services. Report No. ATSDR/TP-88/10, July, 1989.
18. Bittner, A. Surface Coatings Australia, 27 (5): 6, 1990.
19. VanCleave, T.E. Evaluation of Dow 21 to Replace Dow 1: Chromium Reduction
Using Process Consolidation. 7th Annual Aerospace Hazardous Waste Minimization
Conference, St. Louis, Missouri, 1992.
20. Hinton, B.R.W. Metal Finishing, 89 (9): 55,1991.
270
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21. Hinton, B.R.W. Metal Finishing, 89 (10): 15, 1991.
22. Treatment 17 typically requires revivification after 20 fWgal have been treated with
the recommended concentration of 6.7 to 16 oz/gal of sodium dichromate (the pre-
ferred concentration being 13.3 oz/gal). If one assumes the bath contains 6.7 oz/gal
of sodium dichromate after 20 frugal have been processed and that all the loss chro-
mate occurs in the coating, then 6.6 oz/gal of sodium dichromate will be needed to
return the solution to the preferred concentration or 0.1 oz of chromium per square
foot of metal treated would be loss to the coating.
23. Magnesium Elektron Ltd. Surface Treatments for Magnesium Alloys in Aerospace
and Defence. Twickenham, England. 14pp.
271
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272
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
Inorganic Chemistry as an Option for Formulating
High Solids, Low and Zero - VOC Architectural and
Industrial Maintenance Coatings
Christine Stanley
Ameron Protective Coatings Division
201 North Berry Street, Brea, CA 92622
Raymond E. Foscante
Ameron Protective Coatings Division
201 North Berry Street, Brea, CA 92622
INTRODUCTION
Architectural and Industrial Maintenance (AIM) Coatings are required to protect a wide range of
substrates from degradation by a very wide range of environments. Coating systems presently used rely
almost entirely on organic polymers. These chemistries are well established and give proven protection
to stationary structures in many environments. Inorganic polymers have also been used in the form of
inorganic zincs coatings, but these products have limitations in that they are used only on ferrous sub-
strates, have poor aesthetic properties, are not very compatible with organic topcoats and do not give
performance in acidic and caustic immersion service. However, their performance in these limited appli-
cations exceed their organic counterparts. Further, the performance properties of silicone and silicate
resin in baked coatings is well documented and they provide superior properties in heat, UV and chemi-
cal resistance. Silicone resins have also been used to improve the performance of organic polymer coat-
ings. They can improve such characteristics as heat and sunlight UV resistance. Until recently, with the
exception of inorganic zincs and some organic/inorganic copolymers, inorganic polymers were not feasi-
ble for stationary structures because they required baking. A breakthrough in curing technologies has
led to polymers that will film form under ambient conditions to give inorganic backbones. Further, these
coatings can be formulated to very low VOC's either in solvent, 100% solids or water based options. The
performance of these products, in general, exceeds those of organic based coatings.
DISCUSSION
Terminology
For clarity. Table 1 gives definitions of the chemical terminology used in the following discussion. In
coating compositions, the typical resins using the silicon-oxygen bond as the repeating unit in the back-
bone are silicones and silicates. The term polysiloxane can include silicones, but it is used herein in its
broadest sense, that is, any polymeric structure that contains repeating silicon-oxygen groups in the
backbone, side chains, segments or cross links regardless of substitution on the silicon atom. The pres-
ence of certain organic groups bonded to the silicon atom in silicones and polysiloxanes moderates phys-
ical, mechanical and chemical properties, typically in an advantageous fashion1. Oxysilane refers to a sili-
con based structure in which the silicon is bonded to up to four alkoxide or hydroxyl groups thereby ren-
dering that structure reactive to certain condensation reactions; the oxysilane may be monomeric, poly-
meric or a pendant group of a larger molecule.
Comparison of Inorganic and Organic Binders
To understand the performance difference of organic and inorganic products, we must first comment
on comparative chemical properties of the binders (See Table 2). The high bond strength of the Si-O
bond compared to a typical GC bond gives the inorganic structure strength making them more durable
in comparison to carbon based structures. Further, this structure is more inherently heat stable leading
to heat resistance up to 2000°F. By comparison, epoxies and polyurethanes are limited to the 200-300°F
273
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range. Inorganic silicone-oxygen bonds are unaffected by sunlight and ultraviolet attack. By compari-
son, organic binders such as epoxies and alkyds typically show early chalking and fading and
polyurethanes and acrylics will show fading and gloss loss in a 3-5 year period. Since Si-O is already oxi-
dized, polymers based on such a backbone are not affected by atmosphere oxygen and most oxidizing
chemicals. In contrast, organic polymers will eventually oxidize and degrade. An inorganic structure is
not combustible, organic polymers will burn and generate smoke and toxic fumes.
Inorganic Binder Chemistry
Traditional silicone and oxysilane curing involves a process called hydrolytic polycondensation in
which an alkoxide silane is first hydrolyzed and the resulting silanols are condensed to a polymer net-
work (See Figure 1). The innovations being described involve catalysis of this process or direct conden-
sation and the selection of appropriate silicone and oxysilane precursors to produce binders of use in
AIM coatings (See Table 3).
Coating Formulation: Silicones
Silicone copolymers (containing either alkyd, acrylic or polyester coresins) are well known. The
amount of silicone resin incorporated in the copolymer determines the properties of the coating. The
binders are manufactured by condensation at high temperatures. The AIM coatings curing and drying
properties are dominated by those properties of the organic component. Their solids and VOC content
are also dominated by the organic component'.
Coating Formulation: Poiysiloxane
The chemistry described above has been successfully applied to create pure polysiloxane network
binders. These binders have been formulated into pure polysiloxane AIM coatings having maximized
thermal, chemical and UV resistance9. Further, polysiloxane/organic "hybrids" AIM coatings have been
formulated that significantly enhance the properties of the selected traditional organic resin based coat-
ing. As well as high performance properties, these formulations offer advantages in VOC content. This
chemistry increases molecular weight of the binder during the curing of the film to produce solid poly-
mer networks. The silicone and oxysilane precursors used are selected not only for performance but for
their very low viscosity allowing for low VOC content formulations. Pure solvent based polysiloxane
formulas have been produced with volume solids contents of 80-95%. These precursors in hybrid sys-
tems are also selected for their compatibility and diluting effect on the organic components giving coat-
ings a volume solids content of 80-100%. Water borne inorganic binders have also been formulated into
coatings. The pure inorganic versions use silane and silicates as precursors and these systems require no
cosolvents and have 0 VOC. Water borne organic hybrids can also be formulated at low VOC, however,
these do require some oo sol vent to form a film with acceptable performance.
EXAMPLES
The following examples are offered to demonstrate the unique properties provided by utilization of
polysiloxane chemistry in AIM coatings.
Polysiloxane Topcoats
Topcoats have been formulated with both pure polysiloxane and polysiloxane/organic hybrid
binders. Table 4 describes the formulations that exploit the ultraviolet resistance of the siloxane bond.
These formulas have similar appearance to polyurelhanes. Table 5 outlines the formulas' characteristics.
The UV resistance of both these formulas has proved during accelerated weathering tests to be more
resistant than traditional organic based topcoats (See Figure 2). Another interesting property of these
polysiloxane coatings is their inherent compatibility with inorganic zinc silicate (IOZ) primers. As dis-
274
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cussed previously, IO2 primers have superior corrosion performance properties, but limited compatibili-
ty with organic topcoats. Traditionally, a 3 coat system utilizing an 1OZ primer has been used as a high
performance system in the protection of steel in aggressive industrial atmospheres (See Table 6). The
epoxy midcoat is used to tie the IOZ primer to weatherable topcoats that cannot be applied directly to
this primer. The compatibility of the polysiloxane topcoats with the IOZ primers allows a 2 coat system
with obvious advantages (See Table 7).
Water Based System
The above system describes solvent borne topcoats. An alternative to the 2 coat system above is a 0
VOC water based system. IOZ primers are available for both systems that contain 0 VOC This technolo-
gy has been used to formulate a 0 VOC pure polysiloxane, water based topcoat. As with the previous
system, the topcoat is very compatible with the IOZ primer. This system will provide corrosion protec-
tion equivalent to the organic and solvent based polysiloxane system. The finish of this topcoat is flat
and so is not usable where a gloss finish is requested. However, this product will maintain its finish and
not chalk or discolor much longer than organic finishes. Table 8 shows the coating characteristics of this
product.
Heat resistant Polysiloxane Coating
Compositions that contain pure polysiloxane binder networks have been formulated that provide
maximum heat and/or chemical resistance Heat resistance in excess of 1100°C (2000°F) can be achieved.
Typical formulations will contain micaceous iron oxide (MiOx) as the major filler component; the most
successful formulations have the binder to filler ratio as near as possible to the CPVC Table 9 gives a
description of this type of formulation. Figure 3 shows thermogravimetric anaylsis for this type of formu-
lation and Table 10 gives the coatings' characteristics. The weight loss over the temperature range is
around 10%; this accounts for the loss of the organic substituent groups, absorbed water and residual sol-
vent. The remaining film maintains mechanical integrity and continues functioning as a barrier coat
even after high temperature exposure. Table 11 is a summary of representative properties of this type of
formulation*. Typical applications would include stacks, the exterior of reactors and on piping under
insulation. There are no equivalent organic coatings with this level of performance. The closest heat
resistant ambient cure products are silicone alkyds. Their temperature resistance can be as high as
1000°F but their VOC content is generally above 400 grams/liter.
Chemically Resistant Polysiloxane Coating
The same binder system can be used with an optimized pigment package to achieve chemical resis-
tance of a scope not given by organic systems (See Table 11). Indeed, because this type of formulation is
essentially inorganic, it behaves like a zinc silicate without the acid exposure and chemical reactivity lim-
itations. Table 12 describes the coatings characteristics. Polysiloxane tanklining prototypes are resistant
to virtually all solvents, organic acids and mineral acids in certain concentration ranges. However, pure
polysiloxanes are not resistant to alkali. Table 13 is a summary of the representative chemical resistance
of this type of formulation. Tank linings based on organic binders are available. Ambient temperature
cured organic systems generally have good alkali resistance, but only moderate to poor resistance to sol-
vents and acids. These products are available in low VOC content formulations, however, to approach
the resistance of the polysiloxane to solvents and acids, force cure of bake systems are necessary. These
systems are generally higher in VOC content and often include aromatic amine hardners that present
toxiciry problems during application.
In ongoing formulation work, epoxy/polysiloxane hybrids have been developed that cure at room
temperature and combine the resistance of polysiloxane to acids and solvents with epoxies resistance to
alkali. These coatings have shown the best combination of chemical resistance.
275
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CONCLUSIONS
In summary, it should be emphasized that a new formulation chemistry has been described. The
products used as examples typify the first generation of oxysilane and polysiloxane based systems. This
chemistry offers the opportunity for quantum improvements in such performance areas as heat, chemi-
cal, ultraviolet resistance and durability. This chemistry allows the retention of desirable properties in
existing systems while enhancing those areas needing improvement. The use of this chemistry is consis-
tent with the need for developing high performance AIM coating systems that offer reduced environ-
mental, health and safety hazards.
REFERENCES
1. Brown, L.H.; 'Treatise on Coatings"; Myers, R.R.; Long, J.S., Ed.; Marcel Dekker, Inc.: New York,
1972; Vol. I, Part III. Chapter 13.
2. Finzel, W. A.; "Properties of High Temperature Silicone Coatings." Journal of Protective Coatings and
Linings, 1987,4,38-43.
3 Law, G.H.; Gysegem, A.P.; US Patent 4113665,1978.
4 Gasmena, R.L.; Brea, Calif., Oct 1991, Ameron Technical Report 99/91.
276
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TABLE 1
Terminology
Silicon The element (Si)
Silane Substituted silicon compounds
Oxysilane Silicon compounds with at least one substituent an alkoxide, hydroxide or aryloxide
Silicate Metal salt of silicon-oxygen anion
Silica Sand; silicon-oxygen compound
Siloxane Compounds with 2 or 4 oxygens bonded to silicon
Polysiloxane Polymer with silicon-oxygen backbone
Silicone Polysiloxane with organic substiruents on each silicon, typically 2
Organic Carbon based compounds; polymers with carbon-carbon units with backbone
TABLE 2
Comparative Properties
Inorganic and Organic Binders
1. Binder Backbone
\ /
-C-C- 83Kcal/mole
/ \
\
-Si-O- 106Kcal/mole
/
2. Si-O is UV resistant
3. Si-O is already oxidized
4. Si-O is not combustible
277
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TABLES
Advances in Siloxane
Coating Chemistry
• Low/Ambient Temperature Curing
* Silicone Intermediates
* Oxysilane Prepolymers
* Formulation Technique
* Inorganic/Organic "Hybrids"
TABLE 4
Pure Polysiloxane Coating
Topcoat Formula
Description
1. Binder Pure Polysiloxane Backbone
Silicon Substiruents Selected /Balanced for UV Resistance and Film Properties
Cross Link Density Balanced for Film Properties
2. Pigment Selected for Appearance
Full Gloss Range
High, Semi, Flat
3. Curing Ambient Conditions
Single Package
Catalyzed Hydrolytic Polycondensation
Hybrid Polysiloxane Coating
Topcoat Formula
Description
1. Binder Mixed Polysiloxane - Acrylic Backbone
Silicon Substituents Selected /Balanced for UV Resistance and Film Properties
Acrylic Selected for Appearance, Physical, Mechanical Properties
Cross Link Density Balanced for Film Properties
2. Pigment Selected for Appearance
Full Gloss Range
Full, Semi, Flat
3. Curing Ambient Conditions
Catalyzed Polycondensation
278
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TABLES
Characteristic
Pure Polysiloxane
Topcoat
Hybrid Polysiloxane
Topcoat
Number of Components
Volume Solids, %
VOC, grams/liter
Dry to Touch, hrs at 70°F
Dry Through, hrs at 70°F
Application
1
86
129
2
6
Spray, Brush
and Roller
1
85
122
2
8
Spray, Brush
and Roller
TABLE 6
A. Inorganic Zinc
Silicate Primer
Corrosion
Control
Epoxy
Midcoat
Adhesion
Promoter;
Tie coat
Polyurethane
Topcoat
Appearance
Weatherability
Three coats required to make the organic coatings, notably polyurethane, compatible with IOZ
B. Inorganic Zinc
Silicate Primer
Corrosion Control
Polysiloxane
Topcoat
Barrier
Appearance
Weatherability
• Two coats because polysiloxane is inherently compatible with IOZ
• No need for epoxy midcoat to make system compatible
• Epoxy film not needed for corrosion control; IOZ is sufficient
279
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TABLE?
lOZ/Polysiloxane System Advantages
Better weatherability
Same corrosion resistance as three coat
Less manufacturing touch-up/repair
Faster manufacturing turn-around
Lower VOC emissions
Reduced waste generation/disposal
TABLE 8
Coating Characteristics of Pure Polysiloxane
Water Based Topcoat
Components 1
Volume Solids, % 43
VOC, grams/liter 0
Dry to Touch, hrs at 70°F 0.25
Dry Through, hrs at 70°F 12
Application Spray
280
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TABLE 9
Polysiloxane Coatings
Heat and Chemically Resistant Example
Description
1. Binder Pure Polysiloxane Background
Phenyl and Mathyl Substituents to Balance Properties
Oxysilane Cross Linking to Maximize Heat and Chemical Resistance
2. Pigment Micaceous from Oxice
Level to Maximize Heat Resistance
or
Silica/filler Blend to Maximize Chemical Reistance
3. Curing Ambient Conditions
No Baking
Hydrolytic Polycondensation
TABLE 10
Coating Characteristics
for Heat Resistant Polysiloxane
Characteristic
Components 2
Volume Solids, % 90
VOC, grams/liter 96
Pot Life, hrs 6
Dry to Touch, hrs at 70°F 1
Dry Through, hrs at 70*F 24
Application Spray
281
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TABLE 11
Polysiloxane Coatings
Heat Resistant Formula
1. Salt Spray
5000 Mrs
Blistering (ASTM D714)
Corrosion (ASTM D1654)
Scribe (ASTM D1654)
Adhesion
2. Heat Resistance
TGA - Total Weight Loss, to 1000°C
10%
Torch - 1510°C, Discoloration
3. Condensing Humidity
4500+Hrs
Blistering
Corrosion
Adhesion
4. Atlas Cell (Salt and Deionized Water)
1000 Hrs
Vapor Phase
Liquid Phase
5. Chemical Resistance (Representative)
Immersion at 25°C, (Test time, hrs.)
Acetic Acid
50% Sulfunc Acid
19% Hydrochloric Acid
Acetone
Mathylene Chloride
JP-4
Xylene
10
9
10
Excellent
10
9
Excellent
Pass, No Blisters
Pass, No Blisters
(4000)
(4000)
(3000*)
(8000)
(8700)
(1200+)
(8700)
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TABLE 12
Coating Characteristics for
Chemically Resistant Polysiloxane
Characteristic
Components 2
Volume Solids, % 80
VOC, grams/liter 99
Pot Life, hrs 6
Dry to Touch, hrs at 70°F 1
Dry Through, hrs at 70°F 24
Application Spray
TABLE 13
Polysiloxane Coating
Immersion Formula
Representative Chemical Resistance
Acetone
Ketones
Methanol
Alcohols
Xylene
Aromatics
Methylene Chloride
Chlorinated Hydrocarbons
Fatty Acids
Acetic Acids
Organic Acids
Triethanol Amine
50% Sulfuric Acid
83% Phosphoric Acid
10% Nitric Acid
10% Hydrochloric Acid
Not Resistant to Alkali
283
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\
-Si-OH + ROH
\
2 -Si -OH
Figure 1. Hydrolytic Polycondensation of Oxysilane
284
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§§82811 8§f §
Time (Hours)
•ipolysiloxane
*SiliconeAlkyd
^Epoxy
2 Acrylic Polysiloxane
5 SG Acrylic Latex
« Acrylic Polyurethane
Z Alkyd
Figure 2. Comparison of the accelerated ultraviolet
resistance (QUV) of various generic classes of coatings
285
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101.0
100.0
T1 19.7
T2 983.4
Y1 100.0 Wt. %
Y2 912 Wt %
AY -e.8 Wt %
ti.o
0.0 ttO.0 tOOjO MOJO 400.0 900.0 tOO.O 700.0 tOO* §00.0 10OO.O
Temperature (°C)
Figure 3. Thermogravimetric analysis of heat resistant Polysiloxane
286
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SESSION 7
HIGH SOOBS AND WATER-BASED COATINGS
PAPERS PRESENTED:
"The Development of Practical Zero-VOC Decorative Paints"
by
Richard Tuckerman
David W. Maurer
The Glidden Company
Cleveland, Ohio
"New Environmentally Acceptable Metal Coating Systems"
by
Peter C. Ryder
Technical Director
Hawking International Limited
United Kingdom
and
Peter L Hope
Technical Director
LVH Coatings Limited
United Kingdom
"Water-Reducible Polyurethane Coatings for Aerospace Applications"
by
Patricia B. Jacobs
David C. McCiurg (Speaker)
Miles, Inc.
Pittsburgh, Pennsylvania
287
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
THE DEVELOPMENT OF PRACTICAL ZERO VOC DECORATIVE PAINTS
Richard Tuckerman and David W. Naurer
THE GLIDDEN COMPANY
925 Euclid Ave.
Cleveland, OH 44115
The objective of this paper is to paint a picture of some of
the technical challenges associated with the development of a
zero VOC decorative paint. The development of practical, zero
VOC decorative paints presented The Glidden Company with a unique
opportunity to combine the resources of many groups toward a
common goal. These included our internal technical teams working
with external supplier technical groups; Glidden's corporate
marketing, manufacturing, and product regulatory and safety
teams; as well as the regulatory and environmental communities
as a whole.
The paint industry has been in the legislative and
environmental spotlight for several decades now; Even a brief
review of the regulatory climate would include the following
legislation:
The Clean Air Act
The Clean Water Act (CWA)
The Toxic Substance Control Act (TSCA)
The Resource Conservation and Recovery Act (RCRA)
The Emergency Planning and Community Right to Know Act
(RCRA)
Solid Waste Disposal Regulations
State Implementation Plans (SIP)
State VOC Regulations
"Regulatory-Negotiation" Process (Reg/Neg)
The paint industry, as a whole, has been extremely
responsive and responsible in relation to these requirements.
Often, and more importantly, the paint industry has been pro-
active over an even longer time frame in introducing products
that are better, safer, and more convenient for the end user.
The introduction of latex paints, electrocoats, powder coatings
and waterborne can liners are just a few examples.
The trend towards waterborne paints over the past three or
four decades has lead to the present split of 75% waterborne, 25%
solventborne in the decorative paints market. In some segments
of the decorative paints market, ie. wall paints, the percentage
for waterborne paints is even higher, at least 90%.
A typical solventborne decorative coating contains about 45%
solvent, while its latex counterpart contains approximately 7%.
However, when weighted by the proportion of total decorative
products made up of waterborne paints (at least 75%), we see that
the contribution of solvents by waterborne paints is still
significant. We estimate that 20% of VOC emissions from
decorative paints are given off by conventional latex paints.
289
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It was from this perspective that The Glidden Company viewed
the opportunities afforded by a joint project with a major latex
supplier as an opportunity to take action on a significant
contributor to VOC's. This would be a first step, placing
Glidden firmly in the lead in the inevitable drive to remove
petroleum based solvents from decorative paints.
The initial challenges of this project did not deal with
technical issues, but with conceptual ones - the fundamental
goals and definitions which describe both the project and the
product. Working together, Glidden's technical, marketing,
product safety group, along with the latex supplier developed a
primary goal that met the recognized needs for real
accomplishment and commercial success in the marketplace.
Our stated project goal was nto develop a practical,
commercially viable zero VOC decorative paint with all of the
positive attributes of current solvent containing latex paints."
The resultant product target became a high quality latex
semi-gloss wall and trim paint with wet adhesion, block
resistance and durability. We believed that these specific
qualities were essential elements and would present the most
rigorous challenge in formulating without solvents.
To insure a true "break through" technology, the Glidden
team also established rigorous criteria for solvent elimination.
Not only must the product be free of functional solvents,
containing none of the coalescing aids or glycols used in current
latex paint technology, but it roust contain no incidental
solvents which could be carried into the end product (usually in
small amounts) via other paint components.
The technical challenge could now be clearly established
from the goals and definitions reviewed above. To summarize this
challenge the target product a high quality latex semi-gloss,
must contain no solvents, incidental or functional, and roust have
applied characteristics - e.g. film build and open time, flow and
leveling, low temperature film formation, adhesion to hard glossy
surfaces, "block resistance," scrubbability and final appearance
of high quality products based on standard latex technology.
The following is a discussion of paint properties directly
affected by the two major types of functional solvents -
coalescents and glycols.
In standard latex paints, a relatively hard polymer is used
to impart film toughness, durability and lack of thermal tack to
the applied paint film. This polymer, however, may form only a
marginally performing film at normal application temperatures (75
degrees F) and none at all at lower temperatures (40 to 60
degrees F) . A coalescing solvent, which can partially solvate or
soften the outer portion of the discreet latex particles, is
added so that when those particles come into intimate contact
during the drying of the paint film they will deform and
290
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coalesce, forming a continuous film. These solvents leave the
film during the drying process, thereby imparting no permanent
softening to the film.
Glycols, such as ethylene glycol and propylene glycol are
added to latex paints to modify the free liquid phase. Their
primary function is to moderate the rate of dry of a paint film
and thereby impart several useful properties to the paint. These
properties are better application through increased open or
working time, better flow and leveling (both through slowed
evaporation and modification of surface tension) , and improved
gloss. They can also decrease a paint's susceptibility to
freeze/thaw instability during Winter transport and storage.
The key to formulation without these components begins with
the use of a novel latex that can form a film at low temperatures
without solvents yet can be hard enough to promote toughness and
prevent thermal tack. Having established that the neat latex
could form a film at low temperatures without the use of
solvents, an initial paint could be made.
The positive properties of this initial paint formulation
mirrored closely many of the performance characteristics outlined
above. It exhibited low temperature film formation, acceptable
gloss, acceptable open time, adhesion, block resistance, and
durability (scrub) . This was not an unexpected result, as these
properties are dependant in large measure on the quality of the
latex designed.
The goal, however, was to produce a practical semi-gloss
wall and trim enamel and several properties were still
substandard. Chief among these were flow and leveling and
application characteristics, specifically film build (thickness)
and feel under the paint roller.
Beyond these "superficial1* but critical attributes were a
host of other paint properties, hopefully taken for granted by
the end user, but of major importance to the paint formula tor.
These include in-can stability (viscosity changes), control of
syneresis (separation in-can), opacity efficiency (TI02
utilization), foam control, and in-can resistance to
bacteriological contamination. Each of these additional
properties were judged to be marginal or deficient in the initial
paint, and it was here that the technical challenge was most
tested against the zero VOC definition established for the
project.
The properties mentioned above are controlled by the
coatings formulator through the use of additives. These
additives make-up approximately 5% of the final liquid paint. It
is an understatement to say that the formulation of modern,
practical waterborne paints would be impossible without these
materials.
Paint additives which are of primary interest in this
discussion are: rheology control agents including thickeners and
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thixotropes, defoamers, dispersants, surfactants, and in-can
preservatives. This list matches-up well with the list of
deficiencies noted in the initial solvent free paint formulation.
In many instances these additives, common to all latex
paints, contain solvents themselves. These are either carriers
for the active components, part of the active mixture, or merely
residual components from the product synthesis. The key
formulating challenge was to identify specific additives that
were both effective and solvent free. This work was a
cooperative effort with raw material suppliers, who helped
identify or make zero VOC additives and the Glidden technical
teams use of several experimental design techniques, including
full & fractional factorial designs, titration/concentration
studies, and three & four component mixture response surface
designs.
In concluding this section covering the challenges faced in
the development of the initial solvent free paint, we can cite a
specific unexpected consequence of formulating latex products
with no solvent components. During the development work from an
initial paint to the final prototype, the formulating team
discovered a large number of samples that exhibited microcracking
upon drying. This microcracking was followed and observed
throughout the drying process. It began as discreet, pinpoint
discontinuities in the wet film that gradually expanded and often
interconnected, forming the final cracks. This manifestation of
destabilization was evaluated in dozens of samples before a root
cause was found. It was apparent that the removal of all
solvents and solvent containing components from the free liquid
phase of the paint has a profound effect on the paint's ability
to accommodate hydrophobic components. This lack of "bridging
solvents" in the free liquid phase influences stability
properties from short-term storage through to the final
application and dry of the paint film.
The final prototype and its matte sheen companion was
rigorously tested with consumers in "blind trials" comparing the
solvent free paints with their conventional latex counterparts.
Consumers showed a significant preference for the solvent free
paints. An "eggshell" sheen version was created and tested with
professional painters. This product branded, "Lifemaster 2000",
has been aimed at the institutional market - hospitals, schools,
etc...
Beyond achieving the performance milestones which would
assure users of no compromises, these new Glidden products
"Spred 2000 and Lifemaster 2000" bring environmental benefits
leading the way for the decorative paints industry. The absence
of solvent emissions is the technical underpinning for major
reductions in paint odor. Of course, no VOC's are released which
can react with nitrogen oxides in the presence of sunlight to
contribute to urban smog.
These environmental benefits have been recognized by a
variety of organizations including regulatory, scientific
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testing, and environmental groups. Examples include the South
Coast Air Quality Management District 1992 "Clean Air Award",
certification of Spred 2000 as containing "No Smog Producing
Chemicals" by Scientific Certification Systems (Green Cross), and
the National Audubon Society who used Lifemaster 2000 in their
new headquarters building in New York City - a showcase for
environmentally conscious architecture.
In conclusion, The Glidden Company would like to emphasize
that the development of a practical zero VOC decorative paint,
although a technical challenge, was more importantly a multi-
disciplinary challenge requiring innovations of our technical,
marketing, manufacturing and product safety groups, as well as
outside suppliers, coatings specifiers, and end users. It is the
recognition of those challenges and the ability to marshall an
organizations resources to create a viable solution, which is the
ultimate and lasting benefit.
293
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294
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(The work described in this paper was not funded by the U.S. Environmental
Protection Agency. The contents do not necessarily reflect the views of the Agency
and no official endorsement should be inferred.)
NEW ENVIRONMENTALLY ACCEPTABLE
METAL COATING SYSTEMS
By:
Peter C. Ryder - Technical Director
Hawking International Ltd
Peter I. Hope • Technical Director
LVH Coatings Ltd
295
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NEW ENVIRONMENTALLY ACCEPTABLE METAL COATING SYSTEMS
In this paper we are describing a range of decorative and protective polyurethane
coating processes for metals which can replace decorative electroplating, anodizing,
painting and in some cases powder coating. Conventional plating, anodizing and
painting processes all produce environmentally unacceptable effluents which
contaminate local air, water, or both. Although such effluents can be treated in
order to minimise the impact on the environment, new regulations are making
treatment costs prohibitive and even when compliance is achieved there is usually
some form of waste to dispose of.
Our processes marketed under the name of Clearclad and Anoclad are relatively new
to the USA. Marketing only began here about 12 months ago. In spite of this they
are already well tried and proven processes. There are now well over 300
production lines operating throughout the world. A number have now been in
production for over 7 years.
The processes are based on the technology known as Electrophoresis. This process
has been known for well over one hundred years. The first extensive use of the
process was in the 1960's when an anodic coating method for priming car bodies was
developed by Brewer and the Ford Motor Company. All the early processes were
Anodic. This is because the chemistry available at the time favoured the production
of resins suitable for the electrophoretic deposition onto parts forming the anode in
the electrical process. The problem with anodic processes is that, except in the
case of aluminium or very inert metals, making the part to be coated anodic in an
electrolyte causes dissolution and attack pf the metal resulting in discolouration of
the applied coating.. This may be acceptable for undercoats, but is completely
unsatisfactory for one coat decorative systems. These systems only became
practicable with the development of cathodic electrophoretic systems within the last
12 years. The new cathodic materials are based on polyurethanes and will give
clear or opaque coatings on any metal in a variety of colours and effects. They are
quite hard at 3-5H pencil hardness, wear resistant and have excellent exterior
durability.
THE PROCESS
Electrophoresis is the process which occurs when two electrodes are immersed in a
colloidal solution and a voltage is applied across them. Current flows and one of
the electrodes becomes coated with a layer of the material in the disperse phase.
The electrode coated can be either the cathode or the anode depending on the
charge on the dispersed particles. Whilst the process is driven by the applied
voltage, transport and discharge of the dispersed particles is largely influenced by
other processes. Transport of particles is mainly by thermal and mechanical
agitation and the maintenance of a sufficient concentration of the disperse phase in
the colloidal solution. Discharge and coating formation are strongly influenced by
discharge of ions around the electrode,-causing a pH change which destabilizes the
emulsion. The disperse phase particles around the electrode lose their charge,
coagulate and stick to the surface of the electrode. At the same time, the
continuous phase material trapped in the layer is squeezed out by electro-osmosis.
The result is a quite 'dry' electrically insulating layer forming on the electrode.
Once the easily accessible areas are coated, the high resistance of the coating
296
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causes the current to be diverted to uncoated areas until the entire surface of the
electrode is covered. There are, however, limits to this process. The two processes
of electrophoresis and electrolysis are, in some respects, competing. For this
reason, the continuous phase (water in most cases) must have quite a high resistance
or all of the applied voltage will go to drive electrolysis instead of electrophoresis.
This in practice means that the water, which is the continuous phase, must be of
high purity and relatively free from dissolved ions. Because of the high resistance
of the disperse phase, the applied voltage can only.drive the deposition current over
a limited distance. This can be increased by increasing the voltage, but again there
is a limitation. Any coating can only resist a limited voltage. Once this is
exceeded,.the coating breaks down, the current increases, the increased local current
causes local heating of the solution and coating causing film rupture.
Electrophoretic coating materials are carefully formulated to give maximum throwing
power, but this must be consistent with the wet coating having sufficient
conductivity to enable the required film thickness to be built up. The current state
of the art enables thickness of 25 to 40 microns to be coated, whilst giving very
good throwing and covering power; much better than can be achieved with
electroplating.
The two subdivisions of electrophoretic coating are anodic and cathodic processes.
This refers to whether the article to be coated is made the anode or the cathode.
The chemistry involved in one is in effect the mirror image-of the other, but is
easier in the'^case of anodics which accounts for their longer industrial history.
Each process 'has some advantages over the other, the main distinction being that the
anodic version is limited to coating some specific metals, (e.g. Aluminium, Gold
Plate), whereas the cathodic version will coat any metal.
PROCESS MECHANISM
The material is supplied as a resin concentrate at 50-65% solids which contains all
necessary materials to make up a new bath or replenish an existing one. The only
additional materials needed are dyes, pigments, matting agents, etc., designed to
modify the finish.
This concentrate contains:-
The main resin binder modified to render it water dispersable
A water miscible solvent
A blocked cross linker
Catalyst
Water immiscible solvent
Surface active agents, Emulsifiers
A material to provide the counter ion and give the water
phase a limited low level conductivity
When this material is mixed with water it separates into two phases. The
undyed or unpigmented material has a 'milk" like appearance due to the light
scattering properties of the disperse phase.
Our current processes employ blocked isocyanates as cross-linkers. These materials
do not develop isocyanate activity until elevated temperatures are reached and the
blocking agent is split off by the action of heat. We have a range of processes
employing different cross-linker/blocker systems. The unblocking temperatures vary
from 120"C to 147'C. At these temperatures, the activated isocyanates react with
the co-resins to form a polyurethane. The inert nature of the blocked isocyanate at
room temperature ensures long term stability of the concentrated product and the
297
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made up solution. In some cases the systems also employ a catalyst which speeds up
the rate of reaction and this enables good cures to be obtained at quite moderate
temperatures. The coatings cure in the range of 130-160*C, the cure times being
about 15 minutes at metal temperature.
The resin system can be used alone and unmodified to give clear, transparent, almost
invisible coatings which can be used to protect and preserve the underlying metal,
e.g. on polished brass, electroplated silver, etc.
The transparent resins can also be dyed to give a wide range of transparent colours.
These allow the metal to show through but modify its colour. In this way, silvery
white basis metals such as Aluminium, Zinc, Nickel, etc. can be made to look like
gold, brass, copper, pewter, etc. or can be given completely artificial colours e.g.
green, purple, orange etc.
The resin can also be modified by adding opaque pigments to produce a wide range
of solid colours, and black and white. These coatings completely hide the basis
metal. They, and indeed the transparent colours, can in addition be modified to
produce varying degrees of gloss.
The process can be used in many ways. It can be applied after silver plating to
give a clear, invisible coating which prevents tarnishing and resists wear. It means
that drying stain problems are eliminated, and much thinner durable coatings can be
applied. Cost savings are effected by reducing the typical silver thickness over the
bright nickel plate to 0.2 microns. A fully automatic plant using this process has
been in operation for over 7 years.
It can also be applied over polished brass. The coating thicknesses applied have
varied from about 8 microns on items like photoframes to 20 microns on brass door
furniture where it is required to resist wear, weather and sunlight.
A very interesting application is the use of dyed coatings to simulate brass, copper,
bronze and gold. These can be applied directly over polished zinc diecastings
completely eliminating plating operations. This then avoids the use of toxic chemicals
like cyanide, acids, alkalies and metal salts. The problem of spotting out due to
chemicals trapped in pores is also eliminated. The speeding up, simplification, and
reduction in steps in the process is shown in figures It 2 and .3.
Steel can be either coated direct, or where brightening and levelling is required it
can be preplated with a bright levelling acid zinc. This can then be coated with
brass, copper or gold coloured Clearclad to give the required finish. If solid colours
are required, the steel is either coated direct or if maximum corrosion resistance is
required then a phosphate pretreatment is applied. One current application is on
steel outboard motor parts, which in service are partly immersed in sea water.
Coatings carried out on aluminium vary from brass and gold colours to black, white,
brown and bronze colours. 25 micron coatings on aluminium extrusions meet all of
the requirements of British Standards, BS 4842 and the relevant parts of BS 6496.
Environmental Considerations
Our processes described in this paper were designed to be environmentally friendly.
In this respect all of the materials used in the process were reviewed from two main
viewpoints:
1. Do they prevent a hazard to the environment?
2. Are they hazardous to human beings working with them or using the product?
The materials used have been constantly reviewed and already some changes have
been made in formulations .in view of later discoveries about the nature of certain
materials. We can confidently say that the materials currently used are all the
safest available in both respects.
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The second aspect is efficient usage of the materials in the process. This must be
considered in several ways.
1. Losses from the coating evaporation and oven curing:
The coating solution is at least 84% pure water. Of the remaining 16% just over
half is resin solids and other non volatiles which coat out on the work and form the
final coating. Of the other 8% (maximum) 5% is the water miscible solvent which
almost entirely remains in the bath. The remaining 3% is the water immiscible
solvent which largely deposits with the resins onto the part (some passes into the
water phase due to the coupling effect of the water miscible solvent). When all
solvents are extracted from the coating we get a "worst case" measurement of 0.9
Ib/gal which renders the process compliant in all areas of all states. In practice
not all of this material is evolved in oven curing; some remains in the coating. We
are working on improving on even this by using more reactive diluents.
Losses from the bath by evaporation are negligible. The vapour pressure of
materials used is very low - the most volatile material in the bath is water.
Extraction over the bath is not generally necessary.
2. Losses from the coating bath by drag-out
When work exits the coating bath some of the coating solution is dragged out with
it. The amount depends on the shape of the work. The drag-out tank immediately
following the Clearclad tank employs a spray rinse on entry and exit to ensure
efficient removal of the uncoated solids. This material is returned to the coating
tank by ultrafiltration. This is shown schematically in Figs. 4,5 and 6. Ultrafiltration
is a membrane separation process which separates the disperse phase from the
continuous phase. The Clearclad solution is continuously circulated through the
ultrafiltration tube. Water plus water miscible and soluble components permeate
through the membranes. This permeate is fed into the drag-out tank which flows
back into the coating tank thus recovering the dragged out solids. Long term audits
on industrial plants have shown that better than 98% of the material added to the
tank is coated onto the work. The application efficiency of the process is clearly
illustrated by the fact that no rinses running to drain are used after coating.
The ultrafiltration process is also used to continuously purify the coating solution.
Without this water soluble contaminants dragged in by the work, on jigs,
contaminants in the water, dissolution of fallen components etc will raise the
conductivity of the ultra pure water used. This will favour electrolysis over
electrophoresis causing gas production and disrupting the coating. This is prevented
by passing the permeate through a special ion exchange trap which continuosly
removes impurities.
The final rinse in the rinse aid tank which contains a special wetting agent removes
much of the water and prevents dewetting. This final rinse aid bath needs changing
only every few months. Alternatively it can be slowly bled to drain with the
composition maintained by constant top-up.
A standard Ultrafiltration unit suitable for process tanks up to 1200 litres produces
50-60 litres of permeate per hour. To maintain the balance of the bath it is still
necessary to dump a little permeate but this is never normally more than 5% of the
total permeate production.
If all of the permeate were dumped the maximum possible contaminants in it would
be dissolved impurities (anions & cations) 20 ppm, pH 4.2 (mainly due to lactic acid
299
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- a by-product of the anodic reaction), disperse phase solvent 0.4%, continuous phase
solvent 4.0% i.e. total solvents 4.4%. The maximum rate of effluent production will
be 60 L/Hour. In a typical factory doing even minimal finishing operations one
would expect an absolute minimum of 3000/L of water per hour to be continuously
discharged from the plant.
This would give effluent water 'contaminated' with a maximum possible of:-
Total solvents 4.4 X 60 = 2.64L in 3000L of water = 0.88 mls/L :
100
Resin solids :- zero.
Dissolved ions (anions & cations) 20 = 0.33 ppm
60
In normal operations not more than 5% of permeate is dumped. This reduces the
above figures to 0.044 mls/L solvents and 0.016 ppm dissolved ions. The total
dissolved ions figure is. well below all effluent limits we have encountered. The
solvents are all easily biodegradable.
With further improvements we hope to eliminate the dumping of permeate. This will
almost practically eliminate water pollution.
We commissioned a study of EPA VOC Regulations by an Environmental Consultant at
the University of Illinois. This has reviewed the process against regulations in
detail in 10 States (including California and the San Fransisco and L.A. Bubbles).
The study has revealed that "In all cases, in all States investigated, in all areas of
the State, at all levels of production, for new and existing sources, Clearclad was
found to be compliant with all air pollution regulations, with a very comfortable
margin".
In addition to this experience has shown that not only can the process meet effluent
water regulations, but that it can do so without any effluent water treatment.
Applications of Clearclad Coatings
Some advantages of Electrophoretic coating systems are given be tow.
1. No runs, tear drops, sags, or windows in the cured film.
2. Superior adhesion.
3. Precise thickness control.
4. More uniform product therefore more accurate prediction of corrosion
. life of coated components.
5. Excellent coverage with good penetration on to recesses and blind
holes.
6. Low concentration of solvents in a water based application system thus
* No fire hazard
* No need for flame proof equipment
* Low toxicity
* Environmentally friendly
300
-------
7. Low curing temgerature
*Saves on heating costs
* Plated parts can be cured on same jigs without damage to jig
coatings
*No drying is necessary therefore the major problems of drying
stains is eliminated
8. With the ultrafiltration recovery system the ultra high
efficiency of the process means that 97-98% of the material
purchased is coated on to the components.
9. High efficiency means that the process is virtually a closed
loop system and is non polluting.
10. Use of ultrafiltration means that dragged in impurities are
easily removed.
11. Coating baths are extremely stable and have very long life.
CLEARCLAD APPLICATIONS
A list of current Ciearclad Industrial Applications by Industrial Sector, process and function
are as follows:
1.1. L/oor «t winaow furniture i.e. Door & Window
handles, locks, fasteners, hinges, etc.
1.2. Tableware & holloware
1.3. Bathroom fittings
1.4. Car alloy wheel
1.5. Bicycle parts
1.6. Other car parts - exterior - interior underbonnet
1.7. Giftware & fancy goods
1.8. Buttons (mettalic only)
1.9. Trophies (cups.shields, metals etc.)
1.10.Spectacle frames
1.11.Metal parts for leather goods industry (shoe buckles,
comers, etc.)
1.12. Metal furniture & metallic parts for non metal
furniture
1.13. Kitchenware
1.14. Household goods
l.lS.Electrical goods
1.16. Architectural extrusions
1.17. Architectural metal cladding
L18. Display stands
1.19. Costume jewellery
1.20. Toys
2. BY PROCESS
Ciearclad is frequently used over the following plating processes:
2.1. Nickel plating
2.2. Brass plating
301
-------
2.3. Silver platiifg
2.4. Cold plating
2.5. Copper plating
2.6. Bronze plating
2.7. Bright tin plating
2.8. Nickel-chromium plating
2.9. Zinc plating
It is also used directly on the following basis metals which
have been prepared by - polishing, electro or chemical
polishing vibratory or barrel finishing
2.10. Brass
2.11. Silver
2.12. Bronze
2.13. Copper
2.14. Aluminium
2.15. Zinc Diecast (Mazak - Zamac - Etc.)
2.16. Stainless steel
2.17. Some other ferrous alloys
These materials can be forged, extruded, sheet (rolled),
cast etc.
3. BY FUNCTION
Clearclad can be used either clear, coloured or pigmented to
make it opaque. It can be used indoors or outdoors.
* It can be used to produce excellent imitations of more
materials e.g. dyed to simulate gold or brass; clear over
bright tin to simulate silver; flash silver (0.2 micron) to
simulate high quality silver plate or solid silver (no
tarnishing)
* It can be used to produce vivid metallic colours which cannot be
equalled.
* It can be dyed to simulate copper
* It can be dyed or pigmented to simulate black wrought iron. In
all cases it gives excellent wear and corrosion resistance
A Comparison of Brass plated and Lacquered Zinc Die castings with Brass Coloured
Clearclad Coated Zinc Diecastings from an environmental viewpoint
1. Traditional Brass Plate & Lacquer (See Fig. 1)
2. Brass Coloured Clearclad Coating (See Fig. 2)
Life of Product
The life of the product depends very much on the finish and its ability to stand up
302
-------
to its environment. Many factors come into this but two important ones are
corrosion resistance and wear resistance. Realistic accelerated tests for these and
other properties are difficult to devise but two generally accepteo ones are
1. Salt Spray for corrosion resistance ASTM B117
2. Falling Sand for abrasion resistance ASTM D968
The following are comparisons obtained on typical production brass finished zinc
diecast handles:
Brass plated & lacquered Clearclad Coated
Salt Spray ASTM 24 - 96 hours 250 - 500 hours
Abrasion Resistance 2-5 litres 30 - 40 litres
We have customers who are proposing to give 5 and in some cases 10 year
guarantees on Clearclad coated parts. We feel it is very safe to say that the life
expectancy of our coated handles will be at least three times that of brass plated
items. It therefore follows that the requirement to meet market demand is one third
when Clearclad is used. This alone will reduce pollution by two thirds before any
other considerations are made.
Reclamation of Scrap parts
Re-melting plated zinc diecastings results in contaminated zinc alloy due to the
metals with which they have been plated. Re-melting Clearclad coated parts burns
off the organic coating leaving the diecasting alloy uncontaminated.
Some figures from an actual manufacturer
The following are some figures from a manufacturer of zinc diecast hardward
(handles etc). The thickness of Clearclad coated is 20 microns (0.8 mils) plus/minus
2 microns. This thickness was chosen because on most substrates (including zinc
alloy diecastings) the corrosion resistance improves with increasing thickness up to
15 microns (0.6 mils). This thickness is also sufficient to give good enough abrasion
resistance to give a long enough life to most components.
this customer consumes 1900 litres/Kgms (Density=l) per year. At 20 microns (0.8
mils) thickness one litre of concentrate covers 250 square feet of work. A typical
handle is about 0.1 square feet (14.4 sq.inches).
Practical experience over a one year period during which 1900 litres of Clearclad
concentrate were used showed the follow ing:-
Handles coated 4,750,000
Total solvent added to the tank (all water phase, very little of which goes into the
air as VOC) 125 Kgms.
TRAP ion exchange cartridges used 52 (Approx.one per working week).
Cost of solvent added plus trap cartridges used as a proportion of total Clearclad
materials cost 4.6%
303
-------
TOTAL POLLUTION PRODUCED BY THIS PLANT
1. VOC evolved on oven curing : Meets strictest regulations.
2. Evaporation from tank : Negligible
3. Effluent water pollution: Very little - no effluent treatment necessary
4. Scrap components : Very few
5. Disposal of bath material : Not required bath life is indefinite. (In the
event of a catastrophe bath is easily treated for disposal).
6. Remote pollution e.g. as represented by electricity generation is low.
Coating power consumed is very small. Tank heating not necessary.
Oven curing is at lower than usual temperatures.
i.e. Pollution in all respects is LOW!
304
-------
1, Traditional Brass Plate & Lacquer
Polish & Degrease
STEP
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
PROCESS
Soak Clean
Electro Clean*
Running Rinse
.
Acid Dip
Running Rinse
Cyanide Copper Strike*
Running Rinse
Copper Plate*
Running Rinse
Acid Dip
Running Rinse
Nickel Plate*
Nickel Dragout
Running Rinse
Cyanide Dip
Brass Plate*
Running Rinse
Neutralize Dip
Running Rinse
Hot Rinse
Dry
Lacquer
Oven Cure
Total Process Time • 72
Mins.
PROCESS TIME
2.0
1.0
0.5
0.5
0.5
1.0
0.5
10.0
0.5
0.5
0.5
12.0
0.5
0.5
0.5
2.0
0.5
1.0
0.5
1.0
2.0
3.0
20.0
61.0 *
T/T
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
11.0
HEATING^;
60-70*C
60*C
-
-
-
-
-
-
-
-
-
50-60*C
-
-
-
?
-
-
-
70*C
Hot Air
-
POLLUTED AIR
EXTRACTED
Yes
Yes
-
-
'
Yes
-
Yes
-
-
-
Yes
-
-
Yes
. Yes
-
-
-
-
-
Yes
POLLUTED WATER
TO DRAIN (POLLUTANTS
-
Na.Alkali .Silicates, Phosphates,
Wetters!
-
• Zn.SO , F
T
CN'.Cu.Na.Alkalai
-
Cu, CN1 or SO. or Pyrophospha
-
Acid (SO )
"t
-
Ni,S04,Cl,Borates,Brighteners
-
-
Cu, Zn.CN.Na.Cl
-
-
-
-
-
T/T • Transfer Time
* 5 Rectifiers employed all using electric power
There are seven water polluting steps, some alka\lne, some acid. These have to be treated separately. This is expensive, consumes
more power, and produces toxic sludges which have to be disposed of usually in land fills « more remote pollution
-------
2. Brass- Coloured Clearclad Coating
Polish & Degrease as before
STE;P
1.
2.
3.
4.
PROCESS
Clearclad Coat
Dragout Rinse
Rinse Aid Rinse
Oven Core
Total Process Time «
24.5 Minutes
PROCESS
TIME
2.0
0.5
0.5
20.0
23.0
T/T
0.5
0.5
0.5
-
1.5
HEATING
20-25'C (1)
-
40*C (2)
160*C
POLLUTED AIR
EXTRACTED
_
-
-
Yes
POLLUTED WATEI
TO DRAIN
.
-
Absolutely minimal
-
(1) Clearclad Tank may require slight heating or cooling depending upon the ambient temperature.
(2) Optional : Heating is only to speed up drying and preheat for oven.
Note: The plating process require 7 times as many tanks. This equals approximately the same ration of factory floor
space. This in turn reduces requirement for heating or cooling and other associated costs. This also reduces
power consumption and remote pollution.
-------
Fig., JL
EXAMPLES OF SIMPLIFXING SEQUENCE BY USING "CLEAHCL.AD'
Substrate
Zinc Dlecastlng
Zinc Dlecastlng
Steel
Dr aaa
Steel
Aluminium
Aluminium
Surface Finishing
Required
Drass Plating
Antique Draas
brass Plating
Gold Plating
Gold Plating
Dras*a Plating
Gdld Plating
Electroplating
Sequence
Pretreatment - Cyanide Copper -
Acid Copper - Nickel - Grass -
Spray Lacquer
Pretreatment - Cyanide Copper -
Acid Copper - Nickel - Drass -
Black Nickel - Polishing -
Spray Lacquer
Pretreatment - Cyanide Copper -
Acid Copper - Nickel - Brass -
Spray Lacquer
Pretreatment - Cyanldo Copper -
Nickel - Gold
Pretreatment - Cyanide copper -
Acid Copper - Nickel - Gold
Not usually done.
Not usually done.
Tlmo
45 Mln.
45 Mln.
35 Mln.
25 Hln.
30 Mln.
Clearclad Coating
Sequence
Pretreatment - Brass
Colour Clearclad
Pretreatment - Blackening -
Polishing - Drasa Colour
Clearclad
Pretreatment - Zinc - Brass
Colour Clearclad
Pre treatment - Red Colour
Clearclad
Pretreatment - tllckel -
Silver Strlko - Gold Colour
Clearclad
Pretreatment - Brass Colour
Clearcl ad
Pretreatment - Gold Colour
Clearclad
Time
< 6 Hln.
0 Hln.
IS Hln.
6 Mln.
10 Mln.
6 Hln.
6 Mln.
Note : 1. Pretreatment for electroplating la more complicated and time conauming.
2. Stoving time la nob Included In both cases.
-------
Ills, ii
SCHEMATIC DIAGRAM OF CLOSED-LOOP ELECTROPHORETIC SYSTEM INCORPORATING "TRAP"
U)
o
00
1. BATH MATERIAL IS PUMPED THROUGH THE
ULTRAFILTRATION UNIT.
2. THE FILTRATE (PERMEATE) IS PASSED TO:
3. ION EXCHANGE UNIT TO REMOVE METALS AND
OTHER IONS.
A. THE RETENTATE IS RETURNED TO THE BATH.
5. SOME PORTION OF THE TREATED PERMEATE
MAY BE DUMPED.
6. THE MAJORITY OF PERMEATE MAKES UP THE
DRAG-OUT BATH.
7. THE INCOMING PERMEATE DISSOLVES AND
COUNTER-FLOWS DRAGGED-OVER SOLIDS
BACK INTO THE COATING BATH.
In this way the ultrafiltrate and its corresponding retentate are re-combined
in the coating bath. On the way the permeate has been purified of foreign
contaminants and has been used to reclaim dragged-out solids. In this way,
minimal permeate is dumped and the system retains its operating volume. The
combination of Ion Exchange and Ultrafiltration in this closed loop concept
is called TRAP - Total Reclaim And Purification.
-------
Fig. 5.
Concentrate
~). fed Solution
Hollow Fiber principle shall geometry
Exploded ineiv of membrane surface
309
-------
ULTRAFILTRATICN SYSTEM
TRAP CARTRIDGE
CUTLET TO
S==L
DRAXLTT TANK
26.5-C5 CXH U/F TUBE.
0
(LL
i—IN
4
'I
f-
1
1
I
1
1
1
1
1
1
t
-1
—I**
1
1
1
3/1- CONTROL
VALVES.
PUHP TYPE 70/5
INLET.
FRCM CLEARCLAD T/>NK
^ SOLUTION OUTLET.
U/F TO WASTE.
CONTROL YALYE.
310
-------
£!&.*.
COATING SOLIDS/NON-VOLATILE MATTER VS. VOLATILE ORGANIC MATTER
AS SUPPLIED/ItTBATH DEPOSIT
COATING SOLIDS 1000 1000
WATER MISCIBLE SOLVENT 700 10
WATER IMMISCIBLE SOLVENT 300 206
VOC IJAS SUPPLIED"
GM/KG - LB/GAL 500 -.4.16 108-0.9
The residual 690 water miscible + 84 water immiscible solvent
parts remain in the 'bath and are "converted" to COD through
removal by ultrafiltration.
Electrophoretic coating systems differ from conventional spray
and dip paints in that not all of the VOC "as supplied" is
volatilised during application or baking. The deposition
mechanism excludes the majority of the solvent from the applied
coating. This excluded portion of the VOC may be eliminated
by ultrafiltration.
-------
Fig. 8.
TYPICAL BATH CONSTITUENTS OF ELECTROPHORETIC COATING SYSTEMS
U)
M
NJ
"VEHICLE" RESIN
CROSS-LINKER
WATER MISCIBLE SOLVENT
WATER IMMISCIBLE SOLVENT
ADDITIVES/EMULSIFIERS ETC.
PIGMENTS/EXTENDERS/DYES ETC.
WATER
% WEIGHT
5-10
3-6
3-8
2-4
LESS THAN 2
LESS THAN 10
BALANCE
Typical CLEARCLAD bath will contain up to 16% of such
constituents + balance of water. Auto-body primers may
be 30% + balance of water.
-------
(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
Water-Reducible Polyurethane Coatings for
Aerospace Applications
Patricia B. Jacobs and David C. McClurg
Miles Inc.
Mobay Road
Pittsburgh, PA 15205
Solvent-borne polyurethane coatings traditionally have been the high performance coating of
choice for aerospace and military vehicles. State-of-the-art high solids coatings for these
platforms typically have a volatile organic compound content of 420 g/l (3.5 Ibs/gal). (BMS
1060H, MU-C-85285B, MU-C-46168D). The efforts to further reduce VOC have taken
many forms. For polyurethane coatings, two-component water reducible polyurethane
systems make significant reductions in VOC while maintaining the level of performance
expected of traditional polyurethane topcoats.
313
-------
Introduction
The extreme environments aircraft are subjected to dictates the use of high
performance coatings for corrosion protection and camouflage. Aliphatic polyurethane
topcoats have long been the coating of choice for aerospace, because they provide excellent
flexibility, chemical resistance and exterior durability. Traditionally, this high performance
polyurethane coating has been a solvent borne conventional solids system. Aircraft coatings
like all other coatings are being required by new government and local regulations to reduce
vobtiie organic emissions. Raw material manufacturers and coatings suppliers have
developed high solids and waterborne technology to meet these regulations. This paper will
address a new chemistry for low VOC coatings which may have great potential in the
commercial and military aerospace markers in particular.
State-of-the an aircraft coatings for military and commercial aircraft are formulated
at 420 g/1 VOC. These include MU-C-85285B (Type I). TT-P-2756, Mil-C-83286C
(proposed revision) and BMS 1060H. The binder system (which is the largest factor in
determining VOC) for these types of coatings make use of a hydroxyl-functional polyester
polyol crosslinked with a hexamethyiene diisocyanate (HDI) based polyisocyanate to form a
urethane linkage. The polyester polyol is a solid at room temperature, requiring a high level
of organic solvent to reach practical application viscosities, especially when filled with
primary and extender pigments. The polyisocyanate, on the other hand, is a liquid typically
1000 - 4000 cps at 100% solids. It is obvious that modification of the polyol component
will have the greatest impact on the level of organic solvent used in the current coating
system.
Theory of Waterborne Polyurethane Resins
One Component Polyurethane Dispersions
One approach to reduce organic solvent levels in coatings has been to use water as a
carrier. This concept has already been applied in one-component aqueous polyurethane
dispersions. These are binary colloidal systems made from fully reacted, predominately linear
polymers. See Figure 1. Like most organic polymers, polyurethanes are not compatible with
water. In order to disperse them in an aqueous media they are modified ionically and
nonionically with hydrophilic groups.
A coating made from a one-component polyurethane dispersion would contain
pigments, cosolvents and surfactants typically used in waterborne coatings. The VOC of
such systems generally ranges from 240-340 g/1. As water and cosolvent evaporate, a film is
formed via coalescence. For ambient cure systems, however, commercially available, fully
reacted dispersions do not provide the same level of chemical resistance as that of a highly
crosslinked solventborne polyurethane.
Considerable work has been done to crosslink the ionic groups of the dispersion with
polyaziridines and carbodiimides. A Boeing study formulated a series of polyurethane
dispersions and crosslinkers in an attempt to meet the properties of MH-C-83286B1. They
found that this type of crosslinker made a small improvement in the performance of a one
component polyurethane dispersion, but did not meet Mil-C-83286B. Their results showed
acceptable corrosion resistance and flexibility, but failures in chemical resistance and high
gloss.
314
-------
Figure 1.
Preparation of a Polyurethane Dispersion
OCN-R-NCO «• HO-
• OH
0 T O
OCN-R-NHC1© ~~~~- OCNH-R-NCO
CM, O O
I, C CH, OCNH-R-NH
-------
Figure 2.
Hydroxy-functionaJ Dispersion
CH,
2n HO OH » n HOCH,-C-CH,OH * 4n OCN-fl-fCO
COOH
0 0 O CH, 0 O 0
II H II I I II |
OCN-R-NCO OCN-R-NCCCH,-C -CHjOCN-R-NCO—» OCN -R-NCO
H HH * I H H H
COOH
O O O CH, 0 O O
n « « i H u n
OCN-R-NCC—* OCN.R-NCOCH,-C -CHjOCN-R-NCO OCN -R-NCO
H H H I MM H
COO'NHR,'
1.
2. OH-tunettonal Chain T«nnin«tor
Water Dispersible Polyisocyanates
As in the case of polyurethane prepolymers, polyisocya nates are not compatible with
water. Additionally, the concept of mixing a polyisocyanate with water is unconventional
due to its reaction with water. See Figure 3.
Figure 3.
Isocyanate - Water Reaction
R-NCO * HO-H ^ R-NH2 +
Isocyanate Water Amifte Carbon Dioxide
R'—NCO * R-NHj >- U—jj-C-jj-H
Isocyanate Amine H H
Urea
316
-------
These two potential concerns have been resolved through the development of
hydrophillically modified aliphatic polyisocyanates. Depending on the modifying agent, the
water dispersability. functionality, and viscosity of the polyisocyanate can be influenced.
Although less desirable, reducing the polyisocyanate in an appropriate solvent can, in some
cases, improve the dispersion into water.
We know that the uncatalyzed reaction between aliphatic polyisocyanates and water
is very slow2. We theorize that the polyisocyanate reacts preferentially with the hydroxyl
groups of the dispersion over water. Jacobs and Yu3 have monitored the consumption of
isocyanate by "polyol" and water over time, noting a trend for the polyisocyanate to react
preferentially widi the polyol. See Figure 4. As water evaporates from an applied coating,
the polyisocyanare particles coalesce with the hydroxy-functional dispersion. We believe that
after this coalescence takes place, the isocyanate group comes in dose enough proximity widi
the hydroxyl group tp react.
We recognize that some of the polyisocyanate is sacrificed to the water carrier, and as
a consequence, we formulate with a large excess of polyisocyanate to insure complete reaction
of the hydroxyl groups. We have found optimal property development at NCO/OH ratios
of 2.0 and higher. The resultant polymer matrix can be considered a polyurea modified
polyurc thane.
Figure 4.
Isocyanate Consumption vs. Time
c
o
"5
CL.
V)
e
o
u
O
O
£
60-
50-
40-
30-
20-
10-
• OH-ninctional PUD •
• water
9
_
0
w T 1 1 1 1 1 1
01234567
Time Elapsed (hours)
317
-------
Properties
Clear Film Comparisons
To demonstrate the performance range of a two-component water-reducible system,
dear films from a conventional solvent borne polyurethane and conventional one-
component dispersion were compared to films from a two-component waterborne coating
in a common screening test.
Table 1.
Clear Binder Comparisons
MEK2X
Pendulum Hardness (sec)
Reverse Impact (in-lbs)
Tensile Strength(psi)
% Elongation
2K Solventborne1
200+
170
160
4900
<5
2K Solventborne2
200+
23
160
6200
150
2K Waterborne3
200+
134
160
5755
10
IK PUD4
20
70
160
5700
160
'Soventborne HDI polyisocyanate and a highly functional polyester
^Sovcntborne HOI polyisocyanate and a tri-functional polyester
^Reactive two-component waterbome system
4Aqueous polyurethane dispersion
The results from Table I show the increase in chemical resistance (MEK double
rubs) of a reactive two-component water-reducible system over a one-component fully
reacted dispersion. In fact, this screening experiment suggests the two-component water-
reducible polyurethane demonstrates physical and chemical resistance properties of the same
order as conventional solvent borne systems.
Pigmtnted Ccatingi
Camouflage Topcoats
Our development efforts have suggested that this reactive water-reducible technology
would have potential for nearly all high performance topcoat applications. Of particular
interest has been military and commercial aircraft topcoats. Commercially viable coreactants
were formulated in a series of camouflage and gloss coatings, and tested toward the critical
requirements of Mil-C-852858, Type I, MU-C-83286B, and commercial BMS-1060H.
Factors such as NCO:OH ratio, OH-functionality, coreactam molecular weight,
polyisocyanate modifiers, surfactants, and manufacturing procedures were varied in early
formulation development. The results of experimental designs and confirmatory
experiments were used to design formulations for aerospace applications. Responses
measured for these experiments include impact flexibility, low temperature flexibility.
Skydrol resistance, water resistance, adhesion, hydraulic and fuel oil resistance and gloss.
318
-------
Table 2 is a portion of a screening experiment used to determine appropriate NCO/OH
ratios for a camouflage military aircraft topcoats.
Table 2.
Water-reducible Camouflage Coating
NCO/OH
GE Impact
Low Temp Flex1
Mil-L-23699
Skydrol2 Fluid
Resistance
1.5
20
pass
fail
blistered
2.0
20
pass
pass
blistered
2.5
20
pass
pass
3 A pencil
3.0
20
pass
pass
1 A pencil
3.5
10
pass
pass
1 A pencil
* Bend over 1" mandrel at -65°F
* Slcydrol is a registered trademark of Monsanto. A pencil is the drop in pencil hardness after 7 days immersion
in Slcydrol 500B fluid. 2 A pencil with no blistering is considered acceptable.
Several coatings formulations designed to meet the different requirements for Air
Force, Navy and commercial specifications were developed based upon this type of
characterization. The following is an example of a camouflage aircraft topcoat formulation
and test results according to Mil-C-85285B, Type I. Bayhydrol XP-7044 is the OH-
functional polyurethane dispersion and Desmodur XP-7007 is the water dispersible HDI-
based polyisocyanate. An NCO:OH ratio of 3.0 was taken from Table 2 and used in the
following initial formulation because it met the chemical resistance and impact flexibility
requirements for military aircraft. The VOC of the final system is 211 g/1 (1.76 Ibs/gal).
319
-------
Two-Component Waterborne Aircraft Topcoat
f 191 -53
VOLUME
SOLIDS
3.51
0.00
0.28
0.35
0.29
0.60
1.73
3.24
14.49
0.60
RAW MATERIAL
COMPONENT I
WEIGHT
VOLUME
Predispcrsc on Cowles Mixer:
Bayhydrol XP-7044 84.67 9.61
DC ionized Water 162.18 19.47
Byk321
Tinuvin 292
Tinuvin 1130
10% Black Tint Paste
TiO2 R-960
Syloid 234
Letdown:
Bayhydrol XP-7044
FC-430 (20% in H2O)
4.32
2.89
2.89
11.30
57.74
54.06
350.18
28.50
Sand Mill entire Component I ro at
COMPONENT 11
Desmodur XP-7007
Exxate600
Total
111.36
37.12
907.21
0.56
0.35
0.29
1.24
1.73
3.24
39.75
3.34
least 5 Hegman
15.31
_SJfl
100.00
WEIGHT
SOLIDS
33.87
0.00
2.17
2.89
2.89
5.92
57.74
54.06
140.07
5.70
111.36
0.00
416.67
WEIGHT
WATER SUPPLIER
40.64
162.18
0.00
0.00
0.00
5.24
0.00
0.00
168.08
22.80
MILES
Byk-Chemie
Ciba Geigy
Ciba Geigy
DuPont
Grace
MILES
3M
111.36
0.00
416.67
15.31
0.00
40.40
0.00
0.00
398.94
MILES
Exxon
Test Results
Formulation f 191-53
Initial Viscosity #4 Ford 25"
4 Hour Viscosity 33"
VOC 211g/l
60° Gloss 6.0
Scrape Adhesion to Primer 6 kg
7 Day Immersion in:
Mil-H-83282* AE-1.3
MU-L-23699* AE-3.1
GE Impact 20%
Low Temp Flex 1" Pass
1 Year Florida Weathering AE - 0.63
Mil-C-85285B, Type I Control
28"
32"
420 g/1
4.5
5kg
AE-0.7
AE = 2.4
40%
Pass
N/A
*AE is the measure of color change in CIEIAB. Illumunant C color space. It is used as a comparative measure
of fluid resistance.
320
-------
When compared to the solvent borne control at 420 g/l, the two component water
borne system gives comparable performance at less than half the VOC. We are currently
pursuing field trails of this material on operational aircraft.
Gloss Topcoats
One of the drawbacks to some waterborne systems is the ability to achieve high gloss.
A binder system containing Bayhydrol XP-7044 polyurethane dispersion and Desmodur
XP-7007 polyisocyanate performs well in camouflage systems, but it is difficult to achieve a
60° gloss greater than 80. Similar formulations utilizing experimental resins designed for
higher gloss, however, demonstrate encouraging preliminary results for military gloss topcoat
and commercial topcoat applications at VOC's as low as 120 g/l (1.0 Ib/gal).
In the first system, an experimental polyisocyanate (EX-P) has been modified to be
even more water dispersible than Desmodur XP-7007. This new polyisocyanate does not
require reduction in cosolvent for incorporation in water, and when reacted with XP-7044,
films are higher in gloss and more flexible. A third system has made use of a new water
dispersible allcyd (WRA) designed for high gloss. Films made from the WRA/EX-P
demonstrate high gloss, good DOI, and excellent chemical resistance. Initial coatings systems
have been tested for gloss, flexibility and Skydrol fluid resistance as well. See Table 3.
Table 3.
New Resins for Aircraft Topcoats1
VOC
60°/20° Gloss
DOI
7 Day Skydrol Fluid
Resistance2
30 Day Skydrol Fluid
Resistance3
GE Impact4
XP-7044-7007
211
71/33
60
pass
&U
20%
XP-7044/EX-P
128
85/58
82
fail
rail
40%
WRA/EX-P
127
88/78
90
pass
pass
20%
' All coatings tested were pigmented with TiO2 at a pigment to binder ratio of 0.7.
2 Tested over cpoxy primer Mil-P-23377. Failure is defined as a decrease in hardness of greater thane 2 pencils.
' Tested over epory primer BMS 10-79.
4 Tested direct to bare anodized 2024-TO aluminum as in Mil-C-852858.
Summary
Today's aircraft perform very different missions subjecting diem to a wide range of
environments. A military fighter for instance, requires a coating that is very flexible, usually
low gloss, and of moderate chemical resistance. A commercial airliner, on the other hand,
requires a coating which provides excellent chemical resistance to such fluids as Skydrol, high
gloss, and moderate flexibility.
321
-------
The common requirements these types of coatings share are light stability and low VOC.
The performance data described in this paper demonstrate a level of performance of the same
order as traditional aircraft topcoats of all types while reducing VOC by more than 50%.
Products such as the OH-functional polyurethane dispersions demonstrate the excellent
flexibility needed for military aircraft, while we believe the newer generations of modified
polyisocyanates and WRA's provide high gloss and excellent chemical resistance demanded
by commercial aircraft applications.
Our future efforts will be directed at formulating and testing this technology in all markets
including the aircraft industry. Future development will be 1) to continue researching resin
compositions and manufacturing techniques to attain Miles' goal of very low and zero VOC
coatings 2) to more fully characterize weather resistance through accelerated methods and in-
progress outdoor exposures and 3) to pursue field trials of laboratory-proven coatings in
cooperation with coatings manufacturers to ultimately determine coating performance in a
real-life exposure.
322
-------
REFERENCES
1. Swanbcrg, D. Water Reducible Polyurethane Enamel, D180-30690, Boeing 1990,
pp. 49-61.
2. Scnekcr, S.D., and T.A.. Potter, Solvent and Catalyst Effects in the Reaction of
Aliphatic Isocyanates with Alcohols and Water. In: Proceedings of the Water-Borne
& Higher Solids Coatings Symposium, New Orleans, LA, 1989.
3. Jacobs, P.B., Yu, P.C., Two-Component Waterbornc Polyurethane Coatings, In:
Proceedings of the Water-Borne and Higher-Solids, and Powder Coatings
Symposium, New Orleans, LA, 1992.
323
-------
324
-------
SESSION 8
APPOCA11ONS I
PAPERS PRESENTED:
"Water Based and UV-Cured Coatings for Plastics"
by
Edwin C. Laird
Coatings Resource Corporation
Huntington Beach, California
"Water-Borne Lacquers for Aluminum Foil"
by
William F. Marwick
Alcan International Limited
Banbury Laboratories
Banbury, England
"Lower-VOC Coating System Conversion Costs for the Wood Furniture Industry"
by
Mary-Jo L. Caldwell
Midwest Research Institute
Gary, North Carolina
"Development of Ultra-Low VOC Wood Furniture Coatings"
by
Eddy W. Huang
Center for Emissions Research and Analysis
City of Industry, California
and
Larry Watkins
South Coast Air Quality Management District
Diamond Bar, California
and
Robert C. McCrillis
U.S. Environmental Protection Agency
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina
325
-------
(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
Water Based and UV-Cured Coatings for Plastics
By Edwin C. Laird, President - Coatings Resource Corp.
327
-------
I. HISTORY
The evaporation of solvents from coatings has long been
determined to be a cause of smog. The formation of smog has been
directly attributed, in part, to the reaction of organic
hydrocarbons with NOx and sunlight to form ozone in the lower
strata. Solvents were segregated by their photochemical
reactivity. Until recently, these solvents were limited to
allowable prescribed levels in coatings. Recently, regulations
have indicated that all solvents are smog precursors. Thus, all
solvent usage has been regulated, and consequently, their usage
has decreased.
Prior to 1966, coatings for plastics consisted of extremely high
levels of aromatic solvents, branched ketones, and chlorinated
solvents. These solvent rich coatings yielded volatile organic
contents (VOC's) in excess of 700 g/1. As a result of the above
cited regulations, the average VOC levels of most coatings for
plastics have decreased by over 60% to a level of 275 g/1.
It should be noted that although some industries have been able
to reduce VOC levels to this extent, others have not been able to
achieve the same results. To a great extent, due to the lack of
polymer technology advancement, some coatings for plastics, such
as thin film applications used in vacuum metalizing, still emit a
high level of VOC.
The quest for lower VOC emitting coatings has progressed along
two major lines of technology. These two lines are waterbased
systems and ultraviolet radiation cured (UV cured) systems. Both
of these lines of coatings technology, although in their infancy
when compared to the old-style solvent based coatings, have
yielded replacements to the conventional solvent based coatings.
In some instances, these products have not only matched the
solvent based coatings in performance and economics, but have
actually exceeded them.
II. WATERBASED SYSTEMS
The trend to waterbased vehicles constitutes perhaps the single
most important development in the field of plastics finishing
during the last decade. As of 1970, this market had been, with
very few exceptions, almost solely restricted to polymer vehicles
Ed Laird, Coatings Resource Corp.
Waterbased and UV-Cured Coatings for Plastic
328
-------
supplied in solvent. Now, less than two decades later,
waterbased polymers comprise 20% of the vehicles used by the
plastics finishing industry.
Waterbased polymers have developed along three major lines:
styrene-acrylic emulsions, acrylic emulsions, and polyurethane
dispersions. These systems have been shown to be substrate
dependant. A coating that adheres to styrene may not adhere to
ABS. Thus, a careful evaluation of polymer systems is necessary
to determine the optimum performance properties that are desired.
Based upon extensive testing in the plastics industry, the
styrene-acrylic emulsions demonstrate the best overall stability
and adhesion to a multitude of plastics. This is due, in part,
to the styrene component of the polymer. However, if film
clarity and whiteness is of concern, this same styrene component
may be detrimental to the overall finish. When exposed to
ultraviolet light, the styrene component yellows, thereby
detracting from the film clarity. If mar resistance is a desired
characteristic, then styrene-acrylic resins would be a logical
choice due to the hard film produced by the resin.
Acrylic emulsions furnish coatings manufacturers with a broad
array of performance properties including high gloss, color and
gloss retention, and the ability to withstand the degrading
effects of water and harsh industrial chemicals. Best of all,
the coatings manufacturer and user obtains these properties while
avoiding highly toxic and flammable petrochemical solvents.
Polyurethane dispersions provide unique qualities normally
associated with solvent based two component urethanes, while
avoiding highly toxic and flammable petrochemical solvents, much
like acrylic emulsions. Some of the properties associated with
polyurethane dispersions include superior chemical resistance,
light fastness, and adhesion to various plastics. Polyurethane
dispersions are currently used in automotive, aerospace, and
business machine finishes. Although the dry times of the
polyurethane dispersion products rivals those of other polymer
families, the polyurethane dispersion coatings required a little
more time to achieve their properties. In order to accelerate
the attainment of these properties, chemical crosslinkers can be
used.
Each of the above cited systems require coalescing solvent in
order to achieve their optimum performance. As a general rule,
Ed Laird, Coatings Resource Corp.
Waterbased and UV-Cured Coatings for Plastic
329
-------
the harder the polymer, measured by its minimum film forming
temperature (MFFT) and glass transition temperature Tg, the more
coalescent that is needed. Additionally, the evaporation rate of
these coalescing solvents must be slower than that of water.
This is of vital importance in order to mitigate the effects of
humidity. If the relative ambient humidity is high, the
evaporation rate of the water in the coating is retarded. This
creates a condition in which the water is the last volatile to
evaporate from the coating. As a result, improper film formation
is likely to occur. Thus, the coalescing solvent serves a
critical purposes. It softens the polymer matrix so that it
fuses the polymer particles to each other and to the substrate.
The transition from solvent to water systems has not gone without
complications. Most industrial coatings manufacturers and users
learned to work with solvent-borne vehicles and are far more
familiar with them than with waterbased emulsion polymers. The
natural tendency is for the formulator and user to handle and
formulate these polymers in the same manner as solvent-borne
vehicles. This approach may not produce optimal coating on
plastic parts. Consequently, the manufacturer and users were
forced to adapt their processes in order to accommodate the new
technology in coatings. But, as a result of these
accommodations, new coatings have emerged that are
environmentally friendlier and simultaneous yield substitute, if
not superior coatings for the plastics industry.
III. ULTRAVIOLET RADIATION CURED (UV CURED)
Ultraviolet Radiation (UV) cured coatings are comprised of
monomers (a single polymeric unit), oligimers (very short chained
polymers), and photoinitiators. These coatings need to be
exposed to light energy with wavelengths between 240 and 400 nm.
These coatings cure extremely fast at relatively low
temperatures. The entire surface of the part must be exposed to
the light source in order for the reaction to occur. Coatings of
high gloss, high solids, zero VOC, with lower energy costs than
thermal cured systems are readily available.
Monomers are used as reactive diluents since they are inherently
low in viscosity. Their degree of functionality imparts
different properties to the final film. The greater the degree
of functional groups that a monomer has, the more crosslinking
that occurs. This translates to increased hardness and decreased
flexibility. Monofunctional monomers, those with one functional
Ed Laird, Coatings Resource Corp.
Waterbased and UV-Cured Coatings for Plastic
330
-------
group, provide the greatest viscosity reduction.
These materials are the basis for health concerns related to UV
curable materials. Using standard hygienic practices that are
employed when using any coating is sufficient to mitigate any
sensitization that may occur as a result of monomer exposure.
Oligimers are the main polymeric materials used today. They have
a small degree of functionality that allows them to react with
each other and the monomer. Generally, they are difunctional
(two functional groups) low molecular weight polymers with a
backbone comprised of either acrylic, urethane, epoxy, or
polyester. The choice of polymer is dependent on the desired
end-use. All of these resin types impart greater strength,
hardness, solvent resistance, and gloss than their solvent or
waterbased counterparts.
Photoinitiators are, as the name implies, chemicals that initiate
the curing reaction upon absorption of the UV light. The
selection of the photoinitiator is crucial. This minor component
will dictate whether the coating cures and at what wavelength.
The entire UV spectrum can be covered by a variety of
photoinitiators. A curing package is developed by coupling the
wavelength of the light emitted by the UV lamp with the
wavelength absorption characteristics of the photoinitiator.
Pigmented coatings are more complex than clear coatings. This is
due, in part, to the reflection of non-absorbed light. Pigments,
as well as other fillers, absorb radiated light. Each pigment
has its own pattern of UV absorption that needs a photoinitiator
package and lamp designed for it. White UV curable coatings are
extremely difficult to cure, as white is the reflectance of all
light, and the photoinitiators used have a tendency to yellow
with time. UV coatings are intrinsically higher in viscosity
and, in many cases, need to be reduced with solvent in order to
be applied, thus increasing their VOC emissions.
IV. CONCLUSION
Low VOC coatings for plastics have improved exponentially in the
past decade. For many industries, these have proven to be the
Ed Laird, Coatings Resource Corp.
Waterbased and UV-Cured Coatings for Plastic
331
-------
salvation in light of the ever increasing regulatory controls.
Waterbased coatings have become, in roost cases, a direct
replacement for solvent based lacquer systems. Research on new
polymers continues, looking to produce hard durable materials at
even lower VOC levels. Additives are constantly being created to
enhance properties of coatings on exotic substrates such as
polysulphone, PEEK, and high temperature composites. The future
for waterbased coatings indicates that it will experience an
ever-increasing demand, as more and more production processes
substitute waterbased for solvent based coatings.
Ultraviolet curing technology work will continue on the curing of
three dimensional parts, lowering of the expense associated with
the light sources, increasing the power of these light sources,
and developing pigmented coatings. Resin companies have
developed waterbased UV resins that use water, rather than VOC
emitting solvents, to reduce the viscosity of the system. This
necessitates some heat to evaporate the water, but application
becomes much easier. Simultaneously, this would reduce the
amount of monomer that is needed in the system.
Even with these advancements, some coatings for plastics cannot
be reformulated to achieve these same results. In these cases,
the manufacturer must look towards emission control equipment in
order to comply with the current emissions regulations. If this
approach is taken, the capital costs of installation and
operation must be given serious consideration along with
maintenance costs required to keep the equipment in proper
working condition.
In conclusion, it must be noted that although great advances have
been attained in low VOC and zero VOC coatings for plastics, it
is still a technology that is in its infancy. It is hoped that
the tremendous growth in this technology will continue to where
all plastics can and will be coating with low VOC and zero VOC
coatings.
Ed Laird, Coatings Resource Corp.
Waterbased and UV-Cured Coatings for Plastic
332
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Effect of Relative Humidity on the
Evaporation Rate of Water
from Waterbase Coatings
Ol
I
o
o
3
0
100
Time
•• Coatings
A H L > •• II I t V' **
_ ^^ . C <• i |; o i a 111. M
333
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Film Formation of Waterborae
Coatings
w
w
Waterborne coating
on surface
Water evaporation yields
close-packed spheres
with solvent filled voids
Further evaporation and
polymer deformation
yields continuou
Coatings
'
-------
(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
Water-borne Lacquers for Aluminum Foil
William F Marwick
Alcan International Ltd., Banbury Laboratories, Banbury OX16 7SP, England
1. INTRODUCTION
Alcan rolls and converts aluminum foil in many countries worldwide. Facilities are in
Louisville, Kentucky and in Australia, Brazil, Germany, Japan, Scotland and Switzerland.
Particular attention is being paid to VOC emissions from these plants. Low gauges of aluminum
are coated with lacquers, and thus the quantities of organic solvent used are comparatively great
when compared to painting operations carried out on other aluminum semifabricates such as
building siding or extrusions, if the calculation is on the basis of solvent use per tonne of metal.
Water-borne lacquers offer an environmentally beneficial alternative to the use of conventional
solvents, and environmental legislation in several countries (e.g. U.K., Australia) is following
the example of the United States in encouraging the use of water-borne lacquers.
Not all converted foil products can be successfully lacquered with water-borne lacquers.
In particular, food packaging products for which a sterilisation step in required, and where an
interior-lacquered aluminum surface is sterilised after filling with the food contents, need a
combination of chemical resistance and lacquer toughness which is very hard to achieve.
Similarly, packaging products for which the lacquer has to provide both a heat-seal action and
then resist a pasteurisation step, need a combination of properties which are mutually conflicting
for water-borne resins. For these sorts of products, thermosetting vinyls and epoxies will be very
hard to replace.
Some products, however, are relatively easy to lacquer with water-borne lacquers; one of
these is cigarette bundling foil, the interior packaging of cigarettes. Alcan makes this product in
four of the above countries, and this paper discusses technical issues arising in the changeover
to water-borne lacquer for this product, both in terms of the coating formulation and the coating
process.
335
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2. PROPERTY REQUIREMENTS FOR CIGARETTE BUNDLING FOIL
Cigarette bundling foil is a laminate of 22 g/m2 paper and 7 micron aluminum foil,
gummed together with a silicate adhesive. The function of bundling foil is primarily to assist in
the high-speed packaging operation, the cigarettes being first "bundled" in the foil and the carton
being folded and glued around the bundle. The product is particularly suitable for this operation
because of the "dead-fold" characteristic of the foil-paper laminate, and the chief function of the
lacquer is to impart the correct frictional characteristic to the foil surface, to enable the
machinery to handle it properly. There is a minimal requirement for water resistance, and of
course an absolute requirement for an absence of off-taste from the lacquer. Tobacco companies
in the U.K.. mostly use a gold lacquered foil, while in the U.S.A. most lacquer is clear. Color
and gloss are therefore properties which often need to be closely controlled.
3. CONVENTIONAL LACQUER: PRODUCT & PROCESS CONSIDERATIONS
3.1 Product considerations
The conventional lacquer which has been used for many years for cigarette bundling
foil is based on nitrocellulose resin, dissolved in ethanol with some ethyl acetate added, and
containing plasticiser and solvent-soluble dyes.
Gloss and transparency of the nitrocellulose lacquers are very good. Water resistance
is also very good, indeed this property is far higher than the cigarette companies actually need.
Retained odor is potentially a problem for these lacquers, because if there are any high boiling-
point solvents presert, they are difficult to remove completely from the coating. Historically,
this occurs very rarely.
3.2 Process considerations
Gravure-applied lacquers need to have an on-machine viscosity of 20 to 30 seconds
(zahn 2 cup). With a nitrocellulose lacquer this is achieved at about 15% solids in ethyl
acetate/alcohol. The dry coatweight applied is approximately 1 - 1.2 g/m2, so that between
7 and 8 ml/m2 of wet coating need to be applied. This implies a relatively coarse gravure roll,
perhaps 100 lines/inch with 50 micron cell depth. Coating with these parameters is easy from
a production point-of-view; control of color intensity is not difficult, coating machines can run
faster than 400 metres/minute, and coating heads are easy to clean because of the ready
dissolution of the lacquer in solvents. Nitrocellulose lacquers dry readily, but 6 - 7 ml solvent is
given off per square metre of foil.. The high flammability of the solvent mixture means that a
large airflow is needed in the driers; the Lower Explosion Limit for the solvents is 2%, so that
a large amount of air has to pass through and be heated up. Some of Alcan's plants have been
obliged by local legislation to install incinerators to burn these solvent vapors, and this means
both high capital and running costs.
336
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4. WATER-BORNE LACQUER: PROCESS & PRODUCT CONSIDERATIONS
4.1 Product considerations
4.1.1 Resins. Water-borne lacquers can be based on acrylic, sulphonated polyester or
polyurethane resins; there are also some oxidizable alkyds and epoxy-esters for use where alkali
resistance is important. The polyurethanes and sulfonated polyesters both have properties which
make them preferable to acrylics in some applications, but the work reported here focuses
exclusively on acrylics; they will remain the cost-effective choice for many applications.
The essence of formulating a lacquer with water-borne acrylic resins is to build in a mechanism
whereby drying is irreversible. In this way a stable solution or dispersion becomes a water-
resistant film on drying. The mechanisms employed are as follows:
* loss of neutralising ammonia or amine on drying
* coalescence of dispersed droplets.
Acrylic solution resins have enough acid groups to dissolve completely in alkaline water, giving
a clear, viscous solution; they dry only by the first mechanism. Acrylic dispersion resins, which
are polymerised from sub-micron dispersed droplets of monomer, have a higher molecular
weight and only enough acid groups to stabilise the dispersion. They dry by both mechanisms.
These two classes of resin impart both desirable and undesirable properties to the lacquer:
For cigarette bundling foil, the lacquer needs to be coatable at quite high solids, so that the
quantity of water to be dried off is minimised and the coating machine speed is not
compromised. The dried film needs to have some water-resistance. Dispersion resins are thus the
obvious choice for the resin vehicle. However, some degree of redispersibility at the coaler tray
is also important, otherwise the gravure roll cells will fill with coalesced or dried lacquer,
especially if the gravure roll stops momentarily whilst it has lacquer on it. For this reason, a
blend of dispersion resin with some solution resin is best.
SOLUTION RESINS
DESIRABLE
redispersibility at coaler
UNDESIRABLE
high viscosity
slow to dry
poor alcohol & water resistance when dry
DISPERSION RESINS
DESIRABLE
low viscosity
fast drying
water resistant, sometimes alcohol resistant, when dry
UNDESIRABLE
limited redispersibility at coaler
337
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4.1.2 Amine neutraliser. Choice of neutraliser also influences the film-forming process and the
drying rate. Clearly, a volatile base such as ammonia or morpholinc will give the fastest drying
but also the greatest risk of cell-blocking on the gravure roll. An alkanolamine with a lower
volatility reverses this balance. Correct selection depends on machine conditions.
4.1.3 Coloration. Conventional nitrocellulose lacquers for "gold" foil brands predominate in
the U.K. They contain dissolved dyes and are transparent when dry. Replicating these gold
colors with water-borne lacquers is difficult; one can use pigment dispersions designed for
aqueous systems (e.g. Microlith WA series, Ciba-Geigy Pigments Ltd.) but the transparency of
the dried lacquer is reduced, especially if the foil is viewed at a glancing angle. Alternatively, it
is possible to incorporate some dyes (e.g. Savinyl, Sandoz Chemicals Ltd.) in stable dispersions,
and this gives excellent transparent shades. The Savinyl dyes need first to be dissolved in
cosolvents which can then be let down with acrylic solution resins, with water and finally with
emulsion resins; many of the latter are only marginally compatible with the dye-cosolvent
mixtures. Useful cosolvents for the Savinyl dyes include diacetone alcohol, acetylenic alcohols
and isopropanol.
4.1.4 Cosolvent. A small amount of an alcohol or glycol ether cosolvent has a pronounced
effect on the wetting action of water-borne lacquers. Inevitably, the surface tension of these is
higher than for the corresponding alcohol-based nitrocellulose lacquer. This makes water-borne
lacquers more sensitive to the substrate surface. Good coating quality is obtained from an
annealed foil surface. At Alcan, conventional practice is to anneal the coils for 34 hours at
300"C; this removes organic contaminants effectively. Figure 1 shows the effect of some
formulation changes on lacquer surface tension.
Figure 1: Surface Tension of Lacquers
45
Boytiydrait BoytwdroiN
40 • •
O N«aayfl
c 30
•C 25
•> '
20
15
10-
1 10 100
solvent content (%)
338
-------
This was measured on a Cahn Microbalancc using the Wilhelmy plate method; glass slides
of dimensions 24mm x 32mm x 0.15mm were lowered into lacquer samples at 40 microns
per second.
Key to Figure I:
"Bayhydrol I": Bayhydrol LS2884 aqueous polyurethane resin (Bayer AC. D5090 Leverkusen. Germany)
Microlith yellow 2RWA pigment (Ciba-Ceigy Pigments, Manchester, U.K.}
Microlith scarlet RWA pigment (Ciba-Geigy Pigments, Manchester, U.K.)
f Surfynol TG surfactant (Air Products d Chemichemicals , Inc.. Allentown. PA)
042%^ Isopropanol
water
"Bayhydrol //". Bayhydrol LS2884 aqueous polyurethane resin
Microlith yellow 2RWA pigment
Microlith scarlet RWA pigment
0.77% Isopropanol
water
"Neocryl I": Neocryl BT67 acrylic resin emulsion (1CI resins b.v.. Waalnijk, Holland)
Microlith yellow 2RWA pigment
Microlith scarlet RWA pigment
0.77% Isopropanol
water
Neocryl II: as Neocryl I but with more isopropanol.
The general pattern is that, for any water-borne resin system, the addition of a few percent of
solvent improves the wetting. Fair comparisons between one resin and another are difficult,
because some are supplied with small amounts of solvent already present.
4.2 Process Considerations
We have found that efficient coating with water-borne lacquers requires a number of changes to
the process. Firstly, the higher solids content (approx. 30%) of water-borne lacquers at
viscosities suitable for gravure coating (20 - 30 seconds, Zahn 2 cup) makes a lower wet film-
thickness desirable for both economy of lacquer and drying speed. Secondly, the irreversible
film-forming characteristic of the acrylic dispersions makes coating head control very important;
drying of the lacquer in the gravure cells has to be prevented by keeping the roll turning in the
tray even during a machine stop. These and other process considerations relating to water-borne
lacquers have been widely recognised'. Perhaps less well known is the use of fine ceramic
gravure rolls to deposit uniform wet films at very low coatweights. These have been utilised
with very encouraging results. The sequence involved in ensuring that the required dry
coatweight (0.6 g/m2) is applied is shown in figure 2. In this sequence it may be seen that the
desired color shade requires a pigment coatweight of 0.06 g/m2 dry coatweight, which for the
candidate formulation requires 0.6 g/m2 dry coatweight of the complete lacquer. The lacquer
reaches the correct viscosity for coating at 25% solids, and has a specific gravity of 1, so 2.4
ml/m2 wet coatweight needs to be applied. The fine ceramic gravure roll has a transfer factor of
about 40% when coating onto bare aluminum foil; that is to say, the wettability and surface
roughness of the foil in relation to the wettability of the chrome oxide ceramic result in about
40% of the contents of a cell full of lacquer being transferred to the foil.
339
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It is not widely known that the transfer rate of water-borne lacquers from these rolls to
aluminum foil is so low; correct knowledge of this parameter is of course essential if the
correct roll engraving is to be selected.
Thus a gravure roll with a cell volume of 6 cubic centimetres per square metre is
needed; this implies an engraving of the order of 17 microns cell depth and 360 lines/square
inch. This very fine gravure roll gives a welcome benefit in that the spread or lay of the lacquer
coating has been found to be excellent, indeed better than that achieved routinely from the
nitrocellulose lacquer. The laser-engraved ceramic material ("Ucarlox", Praxair Surface
Technologies Ltd., Swindon, U.K.) combines wear resistance with an accurate consistency of cell
dimension across the web; this is of course essential for a colored lacquer, if shade is to be kept
within specification at such a low coatweight.
Figure 2: Gravure roll selection
Lacquer shad* requirement 0.06 tfm2 ptynar*
io 0.1
Dry Coatweight
ttfets contort 25X
wet ooatweigru applied:
eel volume 6 mVm2
enwmlegtf¥unnH,3tOHn9»pfrlneh, 17 mtcnn erf top*
A comparison with the process parameters required for the nitrocellulose lacquers (see 3.2
above) shows that a wet coatweight of 2.4 ml/m2 is applied in the case of these water-borne
lacquers, as opposed to 7 - 8 ml/m2 for the solvent-borne nitrocellulose. This low wet film
thickness overcomes the drying problem, and it also minimises the environmental effect of the
few percent of cosolvent which are included in the formulation to ensure good wetting of the
substrate. Finally, a cost reduction vis-a-vis the standard nitrocellulose lacquer is clearly
obtainable, at least in terms of material costs, since the dry coatweight has been halved and the
two lacquer types are broadly comparable in cost on a dry solid cost basis. Long-term
production experience will be needed before a reliable calculation can be made, which also
includes cost changes arising from the process changes.
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The excellent spread of the water-borne lacquer - referred to above - deserves further analysis; it
relates to the ease with which the dots of lacquer transferred to the foil surface can enlarge and
merge before they become immobilised through loss of solvent. To demonstrate the difference
between the standard nitrocellulose lacquer and a typical water-borne acrylic, the two
formulations were made at a number of higher solids contents than the actual on-machine
formulations, and the viscosities were measured on a Bohlin "Visco 88" viscometer. The results
are expressed in Figure 3 as viscosity against the percentage of solvent lost from the initial
concentration. Expressing the results in this way removes any consideration of relative
evaporation rate, since for any lacquered foil passing through a drying oven, the solvent loss
must progress from 0% to essentially 100% from coating head to coil-up, and this is the time
during which dot-enlargement has to take place. It is clear that the rise in viscosity for the
nitrocellulose lacquer is very sharp; that is why such lacquers can so easily give a mottled
appearance.
Figure 3: Viscosity rise through drying:
nitrocellulose (NC) and aqueous acrylic (aa) lacquers
0.6 . -------------- -
0.5
0 4 • aa
CO
£
2? 0.3
0.2-
0.1
• i
6 8 10 12
solvent tost
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4.2.1 Ultrasonic Cleaning. A process consideration which was mentioned in 3.2 above
was the easy cleanability of the gravure roll when solvent-home lacquer is used. The
water-borne lacquers can give problems in this respect, the drying being much less
reversible than is the case with nitrocellulose lacquers, even when the formulation contains
carefully chosen combinations of resin types, amine and cosolvent. With this in mind, an
on-machine ultrasonic cleaner has been installed. The resonator (Telsonic AG,
Bronschhofen, Switzerland) is in the form of a tube which extends the full length of the
gravure roll, and is located in the lacquer tray underneath the bottom of the roll. The tray
bottom is semicircular in profile, such that ultrasonic waves are reflected upwards onto the
roll surface. The tray can be drained of lacquer and refilled with a mild alkaline cleaner
prior to switching on the ultrasonic resonator. The installation eliminates the need to
remove cylinders from the machine for cleaning; this was felt to be important, because the
brittle nature of the ceramic gravure roll makes it vulnerable to mechanical damage during
handling. Long-term experience of the use of the ultrasonic cleaner has yet to be gained,
but it is certainly effective.
5. CONCLUSIONS
The change from solvented to water-borne lacquers requires some changes to the
coating process, and does not give a cigarette bundling foil with identical properties to the
original product. However, this development work at Alcan has convinced us that there are
as many positive as negative property changes; in addition there is not only an
environmental benefit but also a potential cost saving. Water-borne lacquers are most
useful where local regulations permit small quantities of cosolvents (alcohols or glycol
ethers) to be included.
REFERENCES
1. Podhajny, R. M. Surface Tension Effects on the Adhesion and Drying of Water-
Based Inks and Coatings. In: Proceedings of Fine Particle Society Symposium on
Surface Phenomena and Fine Particles in Water-based Coatings and Printing
Technology, Boston, Mass., 1989. pp 41-58.
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LOWER-VOC COATING SYSTEM CONVERSION COSTS FOR THE WOOD FURNITURE INDUSTRY
Mary-Jo L. Caldwell
Midwest Research Institute
401 Harrisoo Oaks Blvd
Suite 350
Gary, North Carolina 27513
NOTE: Although the research described in this technical paper has been funded wholly or in part by the U. S.
Environmental Protection Agency contract 68-D1-0115 to Midwest Research Institute, it has not been subject to
the Agency's review and therefore does not necessarily reflect the views of the Agency, and no official
endorsement should be inferred.
BACKGROUND
During the manufacture of furniture, volatile organic compounds (VOCs) are emitted from the coating
operation. These VOCs can contribute to the formation of ozone and exceedances of the National Ambient Air
Quality Standard for ozone. In order to attain the ozone standard in many parts of the nation, emissions of
VOCs must be reduced.
The U.S. Environmental Protection Agency (EPA) is currently developing a control techniques
guideline document (CTG) for VOC emissions from wood furniture coating operations. The CTG will be used
by States to develop wood furniture coating regulations. The EPA is also developing a national emission
standard for hazardous air pollutants (NESHAP) for wood furniture manufacturing. Midwest Research Institute
is helping the EPA develop both the wood furniture CTG and the NESHAP. The use of regulatory negotiation,
a type of consensus-building process, has been initiated for both the wood furniture CFG and the NESHAP.
As part of the CTG project, a cost analysis of VOC reduction alternatives was performed. This paper
describes the analysis used to examine the cost to the wood furniture industry associated with adopting coatings
which release less VOC.
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INTRODUCTION
The purpose of this paper is to demonstrate the methodology that can be used to estimate the costs and
emission reduction associated with using lower-VOC coatings. The costs of switching to lower-VOC coatings
are site-specific, and the costs presented here should be viewed accordingly. This paper discusses the initial
cost analysis that was performed for the wood furniture CTG project. The CTG project and the cost analysis
are described in the draft CTG. The original analysis has since been expanded and revised based on
comments and information received from the industry. These revisions have not been finalized and therefore
are not discussed quantitatively here. Because the CTG is currently the subject of a regulatory negotiation
process, the methodology may change before the CTG is complete.
The cost analysis performed for the CTG evaluated two primary VOC control strategies - the use of
add-on controls (with and without exhaust-flow reduction techniques) and the use of lower-VOC coatings. Only
the lower-VOC coatings cost analysis is discussed in this paper.
The control techniques guideline will define reasonably available control technology (RACT). RACT
applies to existing facilities. Therefore, the cost analysis discussed in this paper evaluated the costs of
retrofitting an existing facility to switch from conventional solventborne coatings to lower-VOC coatings.
The objective of the analysis discussed here was to develop the costs and VOC emission reductions
associated with a variety of VOC control strategies. These costs and emission reductions were then used to
calculate the "cost effectiveness* of the various control strategies, i.e., the cost per unit of VOC reduced (S/ton
VOC reduced). The calculated cost effectiveness data were used in conjunction with other information to
evaluate the various control strategies during development of the draft CTG. This paper focuses only on the
development of the cost effectiveness data.
INDUSTRY AND COATING INFORMATION
The wood furniture industry was characterized, and the feasibility of a variety of lower-VOC coatings
was evaluated. In this section, the finishing process is described, the characterization of the industry by model
plants is discussed, and the lower-VOC coatings evaluated are presented.
Finishing Process
The finishing process varies with the industry segment and the facility. Residential furniture
manufacturers generally assemble their pieces and then finish them. The remainder of the industry also
prefinishes some unassembled pieces. The coatings used in the wood furniture industry include but are not
limited to stains, sealers, and topcoats. Coatings are usually spray-applied, although flatline coating methods
such as curtain coating and rollcoating are used as well. The residential furniture manufacturing industry
generally uses manual spraying, whereas the rest of the industry uses both manual and automatic spraying.
The finishing process may be a single step or multistep operation. The coating may be manually or
automatically spray-applied in the spray booth. The piece then leaves the booth and may be wiped before
entering the flash area, where the faster solvents are allowed to evaporate. Depending on the number of steps
in the finishing sequence, the piece may then enter an oven and, after cooling, may be sanded, after which
subsequent coatings may be applied.
Model Plants
A cost analysis for an individual facility would use facility-specific information that presumably would
be readily available. The cost analysis described here was performed for the entire wood furniture coating
industry. Therefore, "model plants" were developed to represent the wood furniture coating industry. The
model plants were developed based on information supplied by wood furniture manufacturers, coating suppliers,
application equipment suppliers, and industry representatives.
In developing model plants, the industry was broken down into two main groups: residential furniture
manufacturers and "other." Included in the "other" category are cabinet manufacturers, office and institutional
furniture manufacturers, and store fixture manufacturers.
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The "other" category uses « finishing sequence that consists basically of applications of stain, sealer,
and topcoat. Residential furniture manufacturers using a short finishing sequence use essentially the same
sequence, except they also apply a washcoat after the stain, before the sealer. Residential furniture
manufacturers using a long finishing sequence use the same coatings as manufacturer! using a short sequence,
but the coatings are applied more frequently and additional coatings, including filler, wiping stain, and highlight,
may also be used.
For purposes of the analysis, the size of the model plants was based on total annual VOC emissions.
Total VOC emissions of 225 tons per year (tons/yr) corresponds to the medium model plant, and 500 tons/yr
corresponds to the large model plant. The smaller model plants were subdivided into three categories with the
following emission cutoffs: extremely small - 10 tons/yr, very small - 35 tons/yr. and small - SO tons/yr. The
very small model plant cutoff has since been revised from 35 to 25 tons/year.
The subdivision of model plants is shown in Figure 1. For model plant purposes, the residential
furniture manufacturing segment, which primarily uses solventborne nitrocellulose lacquer coatings, was further
segregated by short and long finishing sequence, and then by size. The majority of the "other" category
primarily uses acid-catalyzed solventborne coatings and generally one basic finishing sequence. The "other*
industry segment was broken down by manual and automatic spraying, and then by size. Due to the capital
investment required for an automatic spray application system, it was assumed that small facilities would not use
automatic spraying.
Lower-VOC Coatings Evaluated
The first step of the life cycle analysis involved determining which lower-VOC coatings are technically
feasible for the wood furniture coating industry. A detailed description of the lower-VOC coatings available to
the wood furniture industry is not provided here but can be found in the draft CTG.' Initially three primary
lower-VOC coating types were identified as technically feasible for at least some segments of the wood furniture
coating industry: waterborne, polyester, and polyurethane. (The UNICARB* coating system was evaluated
later and this analysis is discussed under the section titled "Additional Costs Evaluated"). Polyester and
polyurethane coatings are similar in terms of VOC content, solids content, and price. Therefore, in the cost
analysis, polyester and polyurethane coatings were treated as a single category, referred to as
polyester/polyurethane (pe/pu) coatings. Waterborne coatings can be used exclusively or in conjunction with
conventional solventborne coatings. Similarly, pe/pu coatings can be used in conjunction with either
conventional solventborne or waterborne coatings, or some combination thereof.
A total of five lower-VOC coating control strategies were originally evaluated: full waterborne, hybrid
waterborne, pe/pu, hybrid pe/pu, and hybrid waterborne in conjunction with add-on controls. A full waterborne
coating system, consisting of all waterborne coatings, was evaluated. A full waterborne coating system was
considered technically feasible for all the model plants except the residential furniture manufacturers using a
long finishing sequence. A hybrid-waterbome coating system, consisting basically of waterborne sealer and
topcoat in conjunction with other conventional solventborne coatings, was considered technically feasible for all
of the model plants. A pe/pu system, consisting of pe/pu sealer and topcoat, in conjunction with conventional
solventborne coatings, was evaluated. A hybrid pe/pu coating system, basically consisting of pe/pu sealer and
topcoat in conjunction with both waterborne and conventional solventborne coatings, was also evaluated. The
pe/pu and hybrid pe/pu coating systems were considered technically feasible for all of the model plants. The
use of a hybrid waterborne coating system in conjunction with add-on controls controlling VOC emissions from
the solventborne coating steps was evaluated but like the other add-on control analyses, will not be discussed
here.
REDUCTION IN VOC EMISSIONS
The thickness of a coating, once applied, is referred to as the coating "build." The build is a function
of the amount of solids applied. For all of the coating steps except stains, washcoats, and highlights, it was
assumed that the amount of coating used is a function of the final coating thickness the user wants to apply to
the piece. Thus, it was assumed that the total amount of solids applied would be independent of the coating
used. The solids content of lower-VOC coatings is generally higher than that of conventional coatings. For the
coatings for which build is important, this translates into decreased coating usage. The amount of lower-VOC
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Residential
furniture
Small 50 tons/yr
Medium 225 tons/yr
Large 500 tons/yr
Short
sequence
Long
sequence
Small j j Medium] J Large { | Small | {Medium| j Large }
Small] [Medium] [ Large | |Medium| [ Large |
Figure I. Model plants for the wood furniture CTG.
-------
coating required wu calculated by multiplying the amount of convention*! coating required by toe ratio of the
solids content of the lower-VOC coating to that of the conventional coating.
For some very low-solids coatings such as stains, washcoats. and "highlights, * color penetration, rather
than build, is of primary importance. Waterborae stains, washcoats. and highlights are formulated such that the
coverage on a per-gallon basis is the same as their solventbome counterparts. Therefore, it was assumed that
the same quantity of these reformulated materials is required as of their solventborne counterparts.
The VOC content of the reformulated coatings evaluated is generally lower than that of conventional
solventborne coatings. Thus, for every gallon of reformulated coating used, less VOC is emitted. Using the
VOC content and the quantity of conventional coating used and the VOC content and usage of the reformulated
coating, the emission reduction was calculated for each reformulated coating step. The approximate VOC
emission reductions associated with each of the reformulated coating systems that were evaluated are shown in
Table 1. In calculating VOC emissions from all coatings, it was assumed that all of the VOC contained in the
coating is emitted.
TABLE 1. REFORMULATED COATING SYSTEMS, REDUCTIONS IN EMISSIONS BY
INDUSTRY SEGMENT. PERCENT
Model plants
Waterborae system
Hybrid waterborne system
Polyester/polyurethane
system
Hybrid polyester/
polyurethane system
Residential furniture
short finishing
sequence
88
59
55
84
Residential furniture
long finishing
sequence
N/A*
54
50
51
"Other* industry
80
55
50
75
*Not applicable.
COSTS ASSOCIATED WITH LOWER-VOC COATING SYSTEMS
The variety of costs that may be associated with switching from a conventional solventborne coating
system to a lower-VOC coating system are shown in Figure 2. These costs may include incremental coating
costs, the cost of increased material storage requirements, the need for additional drying capability,
modifications to the existing coating supply and application system, and the need for a clean room environment.
The costs that will be incurred when switching from a conventional to a lower-VOC coating system depend on
the existing facility and the type of lower-VOC coating system used. Each of these costs is discussed below,
and the methodology used to estimate the costs is described.
Coating Cost
Lower-VOC coatings are usually more expensive on a per-galion basis than conventional solventborne
coatings. However, as discussed above, fewer gallons of many of the lower-VOC coatings are used, due to the
increased solids content. Therefore, there may be an incremental coating cost or savings associated with using
lower VQC coatings. The cost of using both conventional and lower-VOC coatings is calculated by multiplying
the per-gallon cost by the total number of gallons of coating used. The difference between these costs
represents the incremental coating cost. The incremental coating cost of waterborne and hybrid waterborne
coating systems represents from approximately 65 to 90 percent of the total annualized costs of switching.
Incremental coating costs only represent from 1 to 36 percent of the total annualized costs for pe/pu coating
systems, and from 1 to 60 percent for hybrid pe/pu system*.
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COSTS OF SWITCHING
Coating cost
Material storage
Additional drying capability
Coating circulation/application system
modifications
Clean room
Operating costs
Other costs
Figure 2. Potential costs of switching to lower-VOC coating systems.
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Material Storage
In medium and large wood furniture coating facilities, conventional solventborne sealers and topcoats
are usually stored in large bulk tanks located outside the building. The other coatings are usually stored in
SS-gallon drums or other containers inside the building in heated storage areas. In small plants, all coatings are
usually stored inside in containers in heated storage areas. If a facility were to switch to waterbome or pe/pu
sealers and topcoats, the reformulated sealers and topcoats would have to be stored indoors, so increased indoor
heated storage would be required.
The amount of indoor storage required was calculated assuming all coatings are supplied in 55-gallon
drums. It was assumed that due to land constraints, the coating storage building would be beside the existing
building. Waterbome coatings usually contain some solvent, and pe/pu coatings may contain solvent that
becomes part of the final film. Coatings that contain solvent may have to be stored in a 2-hour fire-rated
building if the building is beside the main facility. Therefore, assuming the new storage area would be right
next to the existing building is a conservative assumption. In calculating the amount of storage space needed,
the reformulated sealer and topcoat coating usage was first calculated. Then using the calculated reformulated
coating usage, the turnover rate was increased from once every 3 months to once per month. The storage space
requirements were calculated based on 20 percent excess capacity to provide for increased production. The
installed capital cost of a 2-hour fire-rated building averaged around $380 per SS-gallon drum stored, based on
4 square feet per drum. It was assumed that the existing bulk material storage tanks would be left in place with
no additional expense.
Additional Drying Capability
Some of the reformulated coating systems may require additional drying capability. How this need is
addressed depends on the existing facility, the configuration and speed of the finishing line, the substrate being
finished, and potentially many other factors. In some facilities, the need for increased drying capability may be
addressed by simply slowing down the line (or increasing the amount of time allowed for drying in a facility
without a finishing line). In other facilities, upgrading existing ovens may be sufficient, whereas in still other
facilities additional ovens may be needed. For purposes of our analysis, it was assumed that the additional
drying capability requirement would be provided by adding high-airflow convection ovens to the existing line.
It was assumed that space for the new ovens was available or could be made available at minimal expense.
The number of ovens needed varies depending on the size of the model plant, the type of reformulated
coating system being used, and the number of existing conventional ovens. For the waterborne coating systems,
it was assumed that a preheater oven is needed before any coatings are applied and that an oven is required after
each waterbome coating is applied. It was assumed that the pe/pu coatings cure via a catalytic reaction with the
curing time reduced by means of an oven. Therefore, an oven is needed after each pe/pu coating is applied.
Based on information provided by oven suppliers, it was conservatively estimated that a new 20-foot
long high-airflow convection oven would cost $48,600 installed. In addition to the cost of the ovens, there are
increased electrical and fuel requirements associated with operating the new ovens. These costs are discussed
later with other additional operating costs associated with the use of lower-VOC coatings.
Coating Circulation/Application System Modification
If a facility switches from conventional solventborne coatings to waterborne coatings, some
modifications to the coating circulation and application system will be required. Modifications may have to be
made to the coating circulation system as well as to the supply lines from the mix room to the spray booths and
the application system. The cost to retrofit a facility with an appropriate paint circulation system so that
waterbome coatings can be used is a function of the location of the central mix room relative to the spray
booths (if a central mix room exists), the number of spray booths, and the number of mix tanks feeding the
spray booths.
It was awumcd that in a small facility there is no central mix room and that the coating materials are
pumped directly from a drum. located at the spray booth, to the spray gun. For small model plants a modular
paint delivery system is used to transfer coatings from the drum to the spray gun. A modular system consists of
a coating storage drum, the drum cover and assembly, fluid regulators, valves, pumps, hoses, and a spray gun.
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If waterbome coatings are used, all components of the modular system would have to be made of tUinlcti steel.
Based on vendor information, a cost of $9,100 per modular spray unit was estimated.
For medium and large facilities, it was assumed that a new stainless steel paint circulation system
would be needed if waterborne coatings were used. Modifications to the material transfer lines would be
needed, as well as changes in the mix room and the spray booths. The replacement stainless steel systems were
assumed to be constantly recirculating systems. The constant circulation of waterborne coatings is necessary to
avoid agglomeration of the coating material in the supply lines. The material transfer lines circulating coatings
between the mix room and the spray booths would have to be made of stainless steel. It was assumed for the
purposes of the analysts that new stainless steel transfer lines would be needed at all facilities. Based on
information supplied by wood furniture industry representatives, 200 feet of coating transfer line is needed for
each spray booth. The 200 feet includes 100 feet from the mix room to the booth plus 100 feet of return line.
Based on vendor information, stainless steel pipe (304 grade or better) suitable for the transfer of coatings costs
$20 per foot of pipe, installed.
For waterborne coatings, changes in the mix room will be required to accommodate coating storage, to
agitate the coating material, and to pump and regulate the coating materials. Based on vendor information, the
installed capital cost of a mix tank was estimated as $25,600. The total installed capital cost of the mix tank
assembly (pumps, agitator, valves, regulator, and hoses) was estimated as $8,800.
Modifications would also be needed at the spray booths in medium and large facilities that switch to
wmterborne coatings. The spray booth equipment would have to be stainless steel capable of handling
waterborne coatings; the required new equipment at each booth would include fluid valves, a regulator, a fluid
hose to the gun, an air hose, a paint heater, a spray gun, and an oil/water separator for the air supply. Based
on vendor information, it was estimated that the equipment described above would cost $1.400, not including
the cost of the paint beater. The paint heater would be supplied separately at a cost of $1,850. The above
equipment would be needed at each spray booth.
Clean Room
According to coating suppliers, polyester and polyurethane coatings are very difficult to repair after
curing. If dirt gets on the coated piece before it is fully cured, it cannot be removed by conventional means
such as rubbing and polishing. Therefore, to minimirr the number of rejects that cannot be repaired, the pe/pu
coatings should not be exposed to dirt and should be applied in a clean room environment. A clean room is
maintained at a positive pressure to prevent dirt from entering, and all air entering the room is filtered. The
entire finishing room may function as a clean room, or the clean room may be a tunnel encompassing the
booth/flash/oven area. For the purposes of this analysis, it was assumed that the clean room would be in the
form of a tunnel encompassing die sealer and topcoat spray booth/flash/oven areas.
The size of a clean room is a function of the dimensions of the finishing line and the total exhaust rate
from the clean room tunnel. The cost of a clean room tunnel is very facility-specific and difficult to assess for
each of the broad model plant categories. Two clean room vendors were contacted, but only one supplied the
estimated cost of installing a clean room in an existing furniture coating facility. An approximate cost of $1
million per clean room was provided by one vendor. It was assumed that if pe/pu coatings are used, one clean
room tunnel would be required for each finishing line within the facility. Due to the facility-specific nature of
clean rooms and the single cost estimate, there is less confidence in this estimate than in those associated with
other costs for switching to lower-VOC coatings.
Additional Costs Evaluated
Estimates of several additional costs have been made since the publication of the draft CTG.
Additional operating costs, the cost of using a UNICARB* coating system, and the costs of a flatline coating
operation switching to lower-VOC coatings were estimated and are described below.
Operating Costs. Additional operating costs associated with switching to lower-VOC coatings include the cost
of fuel and electricity required for the new ovens, the incremental waste coating disposal cost, and taxes,
insurance, and administrative expenses.
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Increased fuel tnd electricity costs associated with the additional ovens are operating costs associated
with the use of some lower-VOC coatings. The fuel provides the heat, and the electricity is needed for the
fans. Based on information obtained from furniture and oven manufacturers, the per-oven natural gas
requirements were estimated to be 700 million British thermal units per year.^'3 Oven manufacturers indicated
that a typical oven used in the wood furniture industry requires about 12 kilowatts of electricity to operate.^4
These fuel and electricity requirements translate into an operating cost of approximately $3.470 per oven
annually.
Based on information supplied by wood furniture manufacturing industry representatives, it was
assumed that the volume of waste coating produced is about 5 percent of total coating use. Because the heating
-value of conventional solventborne coatings is relatively high, the disposal cost is relatively low (about
$0.70/gallon of waste coating) . Because the heating value of waterborne coatings is relatively low, the
disposal cost is relatively high (about $3.50/gallon of waste coating). Therefore, when a facility switches to
waterborne coatings, though the total volume of waste coating is less because fewer gallons of coatings are
used, the overall waste coating disposal cost may increase. It was assumed that there is no incremental waste
coating disposal cost associated with the use of pe/pu coatings.
Indirect annual costs are an operating cost associated with the purchase of any equipment.
Administrative expenses were estimated as 2 percent of the total capital investment, and insurance and property
taxes were both estimated to be 1 percent of the total capital investment.
Cost of the UNICARB* Coating System. When the original cost analysis was performed, the UNICARB*
coating system was not being used in production in any wood furniture manufacturing facility. Because it has
since been used in production in several wood furniture coating operations, the costs and VOC emission
reduction associated with the UNICARB* system have been estimated. The UNICARB* system evaluated
consists of reformulated sealer and topcoat being used with conventional coatings. The UNICARB* system can
also be used in conjunction with waterborne coatings, although this option was not evaluated.
The UNICARB* system uses CC<2 to replace some of the solvent in the coatings. UNICARB* coatings
are formulated only with coalescing solvents, diluent solvents are left out. Coalescing solvents are slow
evaporating, fluent solvents are fast evaporating. The highly viscous coating and supercritical CC*2 are mixed in
a chamber and released as atomized paint through a spray gun. The CC^ evaporates from the paint particles
before they contact the product being coated. The deposited paint containing the coalescing solvents cures in the
conventional way.
There is a reduction of VOC emissions associated with the use of UNICARB* coatings. The reduction
in VOC emissions results from the lower VOC content of the UNICARB* coatings and the higher solids
contents of the coatings, similar to the waterborne coatings. The major costs associated with switching from
conventional solventborne coatings to a UNICARB* coating system include the incremental cost of the coatings,
royalty costs, the need for additional drying capability, the UNICARB* spray system, COj and tank rental, and
CO2 storage. The methodologies used to estimate these costs are described below.
Because acid-catalyzed UNICARB* coatings have not been developed and UNICARB* spray equipment
as presently designed cannot spray two-component coatings, it was assumed that UNICARB* coatings are not
presently feasible for the "other* industry segment using acid-catalyzed coatings. For residential furniture
manufacturers, the UNICARB* coating system consists of UNICARB* sealer and topcoat with conventional
nitrocellulose coatings for the remaining coating steps.
The incremental coating cost associated with using UNICARB* coatings was calculated in the same
way as that for waterborne coatings. Generally less of the UNICARB* coatings are required because of the
higher solids content; however, they are generally more expensive on a dollar-per-gallon basis. Incremental
coating costs represent from 13 to 50 percent of the annualized costs of switching to the UNICARB* system.
The reduction in VOC emissions for UNICARB* coatings was also calculated as it was for the waterborne
coatings, as previously described. The emission reduction associated with the use of UNICARB* coatings
varies from about 35 to 40 percent.
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There is a $2/gallon royalty charged by Union Carbide, the developer of the UNICARB* system. The
user must pay Union Carbide $2 for every gallon of UNICARB* coating sprayed.
In reformulating conventional nitrocellulose coatings to make UNICARB* coatings, the faster solvents
are replaced with supercritical CC^. Although UNICARB* coating manufacturers have attempted to minimize
the drying time required with UNICARB* coalings, additional drying time and/or airflow is still required in
some instances. Therefore, it was assumed that an oven is needed after each UNICARB* coating is applied.
The capital and operating costs associated with the additional ovens were estimated as described previously for
waterbome coatings.
The UNICARB* coatings require a specialized spray application system to apply the coatings. At
present, Nordson Corporation is the only application equipment vendor that is manufacturing the UNICARB*
spray application systems. According to information supplied by Nordson in 1992, a typical 0.4-gallon-per-
minute unit designed for the wood furniture industry costs $35,000. This cost applies to a predesigned unit,
with one spray gun. Each additional gun costs about $625. Installation costs depend on the distance to the
CO2 source and the coating material supply source but typically costs around $4,500.7>8
A single UNICARB* spray application system can supply multiple spray guns. The number of guns is
theoretically limited only by the maximum possible flowrate of the unit; Nordson Corporation has found that
about four guns is the practical limit. Sealer and topcoat cannot be sprayed from the same unit. The furniture
industry often uses multiple sheens of topcoat, and Nordson Corporation has designed and tested a unit that can
spray multiple sheens of topcoat. The additional manifolds and reservoirs needed to spray four different sheens
adds $10,950 to the cost of the unit; each additional sheen costs $2,000.8
In developing the costs for the model plants, it was assumed that regular UNICARB* units are used to
spray sealer, and multisheen units are used to apply topcoat. The number of units required was determined by
the finishing sequence and the number of finishing lines. For each model plant, it was estimated that one
additional multisheen unit would be purchased as backup.
As previously mentioned. CC«2 is required when using UNICARB* coatings. Based on information
provided by the UNICARB* equipment manufacturer, the cost of CQ^ tank rental plus the cost of the CCU was
$1.17/gallon of coating sprayed.' In most instances, the CC^ is stored in bulk storage tanks.7-8 It was
assumed that a storage building would be required for CC^ storage and that the storage building would cost
$15,000.5
Operating costs associated with the purchase and use of a UNICARB* coating system include the cost
of fuel and electricity for the new ovens, and taxes, insurance, and administrative costs. These operating costs
were estimated for the UNICARB* system using the same methodology as that described earlier for the
waterbome and pe/pu coating systems. It was assumed that there is no incremental waste coating disposal cost
associated with UNICARB* coatings.
Flatline Coating Operations. Some percentage of the furniture manufacturing facilities presently use flatline
coating operations to apply some or all of the coatings. Some additional percentage of the industry spray-
finishes flat components and then assembles the components. In many instances, these operations could also use
flatline finishing methods. The methodology that could be used to estimate the costs is presented, but due to the
preliminary nature of the estimates, the results are not presented.
If an existing flatline coating operation were to switch from conventional solventborne coatings to
lower-VOC coatings, the VOC emission reduction would be associated with the decrease in usage associated
with the higher solids content and the lower-VOC content of the lower-VOC coatings. The costs associated
with such a switch would include the incremental cost of the coatings and other operating costs (oven electricity
and fuel requirements, incremental waste disposal costs, and taxes, insurance, and administrative expenses).
If an existing spray operation using conventional solventborne coatings was to become a flatline coating
operation using lower-VOC coatings, the total coating usage would decrease for two reasons: the increased
solids content of the lower-VOC coatings and the increased transfer efficiency associated with flatline
352
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application compared to that of spray application. The costs of such a changeover would include the
incremental coating cost (or savings), the cost of the flatline coaler, the cost of removing the old line, the capital
and operating costs of additional ovens, the incremental cost of waste coating disposal, and taxes, insurance, and
administrative expenses.
OTHER CONSIDERATIONS
There are other factors to consider in converting a facility from a conventional solventborne system to
pe/pu coating system, a waterbome coating system, or a UNICARB* coating system. These factors are
discussed here, but costs associated with these factors have not been assessed in this cost analysis because of
their facility-specific nature.
The first factor regards physical modifications that a plant must undergo to accommodate pe/pu coating
systems. If a facility were to convert some or all of its coating steps to a pe/pu coating system, the facility
would probably remove the existing finishing line (or a portion of it) and replace it with a new line housed in a
clean room environment' This differs from the conversion to a waterbome coating system in which the facility
would most likely retrofit the existing line(s). The cost for a facility to remove an existing finishing line may
be significant but is not incorporated into the total installed cost of $1 million for a clean room runnel. Also, it
was assumed that the pe/pu coatings are two-component catalyzed coatings. *"•'' Catalyzed pe/pu coatings
must be applied using two-pack spray application equipment. The catalyst must be measured (weighed) prior to
mixing and an exact amount of catalyst is required.'2 The cost analysis in this chapter does not account for the
replacement of existing spray equipment with the two-pack spray equipment, neither does it incorporate the cost
of scales for weighing the catalyst and the cost to train workers to perform such a task. Also, the short pot-life
of the pe/pu coatings may result in a cost to the plant in terms of more waste, but this cost is not accounted for
in this analysis.
Another factor to consider in converting from conventional solventborne coatings to a reformulated
coating system is costs associated with downtime. Whenever a new coating system is installed, there is
downtime associated with the installation and training of the workers. These costs have not been assessed. One
final consideration in implementing a pe/pu coating system is the toxicity of the coating materials. Air purifying
respirators and, in some ins^ry^*, supplied air respirators are required when applying pe/pu coatings. The
cost analysis in this chapter does not account for the cost of this equipment, the cost to train workers to operate
while wearing this equipment, or the cost of lost production, if any, due to the decreased mobility of the
worker.
Several potential savings were also not quantified due to their facility-specific nature and the difficulty
of quantifying the monetary value of reduced employee exposure. Savings may result from switching from
solventborne to lower-VOC coatings due to decreased worker exposure. The reduced exposure to solvents may
result in • health benefit to the workers, which could conceivably result in decreased worker absenteeism.
However, it is difficult to accurately quantify the monetary value of decreased worker exposure or any decrease
in absenteeism that may result.
Savings may result from decreased insurance premiums if a facility switches from solventborne
coatings. However, a Factory Mutual representative said that insurance premiums would not automatically
reduce if a facility switched to waterborne coatings. The representative indicated that decisions regarding
premiums are site-specific, and an analysis of an entire facility would be required.
CONCLUSIONS - COMPARISON OF REFORMULATED COATING SYSTEM TOTAL COSTS
Bw-amf the final wood furniture CTG is currently involved in a regulatory negotiation process, and the
model plants and associated costs may change as a result of that process, the individual model plant costs that
were developed as a result of the first cost analysis will not be discussed specifically. Instead, the relative cost
effectiveness of the various lower-VOC-coating alternatives evaluated are discussed.
The cost effectiveness of the five lower-VOC coating systems evaluated is presented in Figure 3.
Generally, the analysis indicated that for the model plants evaluated, hybrid waterborae is the most cost-
effective lower-VOC coating system alternative, with cost effectivenesses ranging from around $l,300/ton to
353
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UNICARB
HYBRID WATERBORNE
u>
Ul
WATERBORNE
PE/PU
PE/PU HYBRID
2,000 4,000 6,000 8,000
COST EFFECTIVENESS ($/TON VOC REDUCED)
Figure 3. Cost effectiveness of lower-VOC coaling systems.
10,000
-------
$2,800/ton of VOC reduced. The UNICARB* coating system's cost effectiveaen ranges from around
$l,200/ton to S4,300/ton of VOC reduced. The cost effectiveness of waterborne coating systems ranged from
about $2,200/too to $3,SOO/ton of VOC reduced. The cost effectiveness of pe/pu and hybrid-pe/pu coating
systems is considerably higher in most instances (up to around $9,600/ton).
Caution should be used in evaluating the cost effectiveness of the pe/pu and hybrid pe/pu systems. The
lower cost effectiveness estimates for these systems correspond to the residential furniture (long finishing
sequence) and "other* (automatic spraying) model plants. Uncertainty in the estimate of clean room costs and
the flowrates associated with automatic spraying operations results in uncertainty in the cost effectiveness
estimates for these model plants. The actual cost effectiveness estimates for these model plants may be higher.
The UNICARB* coating system is presently not feasible for the 'other* category, which generally uses
acid-catalyzed coatings. The cost effectiveness of the other four lower-VOC coating systems evaluated is
generally higher for the 'other* industry than for the residential furniture industry. That is, it is generally more
expensive to reduce a ton of VOCs emitted for the 'other* industry than it is to reduce a ton of VOCs for the
residential furniture industry. The coatings used today by the 'other* industry segment are higher in solids than
those used by the residential furniture industry. Therefore, the decrease in coating usage associated with
switching to a lower-VOC coating is less for the 'other* industry than for the residential furniture industry.
This relatively small decrease in coating usage for the "other* industry translates into a higher cost per ton of
VOC reduced.
The costs and emission reductions presented in this paper were developed based on the best information
available at the time. The purpose of the paper is to demonstrate the methodologies that can be used to estimate
the costs and emission reductions associated with using lower-VOC coatings. As the regulatory negotiation
process progresses, and more information becomes available, the estimated costs may change.
355
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REFERENCES
1. Guideline Series - Control of Volatile Organic Compound Emissions from Wood Furniture Coating
Operations. Draft Chapters 1-5, Appendices A and C. U. S. Environmental Protection Agency, Office of
Air Quality Planning and Standards, Research Triangle Park, North Carolina. October 1991.
2. Telephone Conversation. Christie, S., Midwest Research Institute (MRI). with Miller. D.. George Koch &
Sons, Inc. October 21, 1991. Propeller oven fuel consumption.
3. Telephone Conversation. Caldwell, M., MRI, with Sale, W., Broyhill Furniture Industries. September 17,
1990. Clarification of survey response.
4. Telephone Conversation, Caldwell. M., MRI. with Carl, D., George Koch & Sons. March 11, 1992.
Information regarding turbulator ovens.
S. ENSR Consulting and Engineering. An Evaluation of VOC Emission Control Technologies for the Wood
Furniture and Cabinet Industries. Volume I of D, Technical Feasibility and Costs. Sponsored by the
American Furniture Manufacturers Association, Business and Institutional Furniture Manufacturers
Association, and National Paint and Coatings Association, 1992. 200 pp.
6. Telephone Conversation, Caldwell, M., MRI, with Morgan, R., Union Carbide Chemicals and Plastics
Company, Inc. May 7, 1991. The use of UNICARB* with acid-catalyzed coatings.
7. Telephone Conversation. Caldwell, M., MRI. with West, T.. Union Carbide Chemicals and Plastics
Company. Inc. April 2. 1992. The UNICARB* system.
8. Telephone Conversation. Caldwell, M., MRI, with Daignault, C., Nordson Corporation. April 6. 1992.
The UNICARB* spray system.
9. Miller. S. High Solids Coatings. Products Finishing 1990 Directory, pp. 32-37.
10. Telephone Conversation. Caldwell, M.. MRI. with Riberi, B., Mobay Corporation. August 27, 1990.
Clarification of survey response.
11. Dombey, S. Woodworker's Guide to Conventional Finishes. Furniture Design & Manufacturing.
January 1988. pp. 54-57.
12. Schrantz, J. Regs Could Severely Impact Agricultural/Heavy Construction Equipment Finishes. Industrial
Finishing. May 1991. pp. 21-26.
13. Telephone Conversation. Beall, C., MRI, with O'Block, S., Miles, Inc. January 22, 1992. Toxicity and
safe handling of isocyanatea.
14. Telephone Conversation. Beall. C., MRI. with Febo, F., Allendale Insurance Company. January 2 and 3,
1992. Impact of various control options on insurance premiums for the wood furniture industry.
356
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DEVELOPMENT OF ULTRA-LOW VOC WOOD FURNITURE COATINGS
Prepared By:
Eddy W. Huang
Center for Emissions Research &. Analysis
dry of Industry, California 91748
Larry Watkins
South Coast Air Quality Management District
Diamond Bar, California 91765
Robert C. McCrillis
17.5. Environmental Protection Agency
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
357
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ABSTRACT
It is estimated that the annual U.S. market for wood coatings is approximately 240,000 mj (63
million gallons). On this basis, between 57 and 91 million kilograms (125-200 million
pounds) of volatile organic compounds (VOCs) are emitted into the air each year from the
use of presently used water-borne and solvent-borne systems. The use of "VOC-free"
formulations where possible would reduce such air pollution while providing new markets for
industries.
Adhesive Coatings Company (ADCO), a small firm specializing in low VOC, two-component,
water-based epoxy coatings, holds patents on some of these formulations. Polymer
composition variations of the basic epoxy polymer in combination with each of several curing
agents were prepared. The resulting emulsions were analyzed through laboratory tests to
measure gloss value, drying time, hardness/flexibility, level of solvents, and chemical and
stain resistance.
The new formulations contain < 10 g/1 (0.1 Ib/gal) VOCs which means that these coatings
emit practically no VOCs. The physical properties in the can, as applied, and as the cured
finish are discussed.
DISCLAIMER: The work represented by this document has
been funded in part by the U.S. Environmental
Protection Agency. The document has been subjected to
the Agency's peer and administrative reviews and has
been approved for publication. Mention of trade names
or commercial products does not constitute endorsement
or recommendation for use.
1.0 INTRODUCTION
It is estimated that the annual U.S. market for wood coatings is approximately 240,000 m3 (63
million gallons). On this basis, between 57 and 91 million kilograms (125-200 million
pounds) of volatile organic compounds (VOCs) are emitted into the air each year from the
use of presently used water-borne and solvent-borne systems. The use of "VOC-free"
formulations where possible would reduce such air pollution while providing new markets for
industries.
The South Coast Air Quality Management District (SCAQMD) Rules 1104 and 1136 - Wood
Products Coatings require reduction of VOCs from such sources. It is estimated that
SCAQMD-wide compliance with these rules would reduce VOC emissions by about 18 Mg
(20 tons) per day through a gradual shift from high to low VOC coatings. By phasing in low
VOC coatings, instead of requiring installation of add-on controls, SCAQMD believes that
furniture manufacturers will be able to comply with SCAQMD's rules without increased
costs. To remain competitive in the regulated South Coast Air Basin, coatings formulators
and furniture manufacturers have expressed interest in seeing further developments in low
358
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VOC coatings technology.
Adhesive Coatings Co. (ADCO), a small firm specializing in development and
commercialization of low VOC, two-component, water-based epoxy coatings, is currently
developing coatings which will comply and/or exceed the emissions standards set forth in
Rules 1104 and 1136. ADCO currently holds patents on some of these formulations. It is
estimated that new formulations of these two component water-based epoxy coatings have the
potential to achieve a significant share or complete replacement of the current organic
solvent-based coatings. The new formulations contain < 10 g/1 (0.1 Ib/gal) VOCs which
means that these coatings emit practically no VOCs.
Several large companies that manufacture and supply products used in the wood coatings
industry have been contacted. The product marketing discussions have centered on how best
to commercialize specific ultra-low VOC finished coating applications. Discussions already
are underway with two major corporations, both of which are worldwide suppliers of
industrial products and services to the coatings, adhesives, and polymer industry and
recognized as leaders in providing coatings and ancillary products for the wood industry.
Project Participants:
ORGANIZATION CONTACT PHONE NO.
Center for Emissions Eddy W. Huang (818) 854-5868
Research & Analysis
U.S. Environmental Robert C. McCrillis (919)541-2733
Protection Agency
Adhesive Coatings Co. James Shannon (415) 571-7947
South Coast Air Quality Larry Watkins (909) 396-3246
Management District
2.0 OBJECTIVES
The objective of this project is to develop new low/no VOC wood coatings through
continuing research, formulation adjustments, and application testing. In addition to the basic
development of the coatings, a marketing plan will be developed to get the products of this
project into the public's use.
Efforts are dedicated to conduct joint research into new promising technologies that are
sufficiently mature for demonstration to wood product manufacturers. The high value added
coating products are developed utilizing existing technical know-how, data, and patents
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related to the new technologies.
3.0 PROJECT DESCRIPTION
This new wood coating system consists of an epoxy component (Part A) and an amine curing
component (Part B). The complete absence of organic solvents means that this new coating
system is not only less hazardous to use but emits practically no VOCs and therefore does not
significantly contribute to air pollution. The ultra low VOC content of these new wood
coatings was confirmed by tests at the Center for Emissions Research & Analysis (the Center)
(see Table A). This new two component water-based epoxy wood coating system has the
potential to set a new standard and therefore replace a very significant share of current
organic solvent systems in use.
3.1 Coating Characteristics:
This new ultra-low VOC wood coating system is a high performance, two-pan, chemically
cured, water reducible, fast drying, epoxy product used as a wood coating. It is a hard,
durable primer coating that can be applied to a variety of wood surfaces. The coating system,
as it now stands, has the following performance properties:
(a) Less than 10 g/1 (0.1 Ib/gal) VOCs,
(b) Liquid with rapid initial drying characteristics upon application,
(c) Hardness,
(d) Flexibility,
(e) Chemical resistance,
(0 Effort still required to improve sandability, and
(g) Effort still required to lessen wood discolorization.
3.2 Technical Approach:
The coating development steps are to make the necessary formulation adjustments, continue
with application testing to improve the product characteristics, and overcome the
shortcomings. The goal of the project is to develop a wood coating system that will set new
industry standards for VOC levels.
360
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The results of the research procedures and laboratory tests are documented and written status
reports are prepared detailing the work completed to date along with the identification of
areas that may require further investigation.
The technical approach has centered around the following activities:
1. Work towards reformulating ADCO's patented epoxy polymer in combination with
different curing agents.
2. Identify those compositions that yield the best overall coating performance in terms
of gloss value, drying time, hardness/flexibility, and chemical and stain resistance.
3. Conduct the emission tests required to determine whether the compositions selected
have less than 10 g/1 VOCs.
4. Formulate emulsions with white pigment for those compositions that meet the
performance criteria and emissions limits.
5. Identify those pigmentations that yield the best overall coating performance in terms
of gloss value, drying time, hardness/flexibility, and chemical and stain resistance.
6. Conduct the emission tests required to determine whether the pigmentations selected
have less than 20 g/1 VOCs.
7. Prepare different finished wood panel coupons, both clear and pigmented, to
demonstrate finished coatings that meet the performance criteria and emissions limits.
8. Assess the market acceptance by a written survey and develop two annual marketing
reports to summarize the survey results, manufacturer acceptance, cost benefits, and
any application limitations.
33 Task Description:
The program for making formulation adjustments and undertaking the necessary application
testing to meet the desired product characteristic goals are outlined in the following tasks:
Task 1 - Formulation variations
Polymer composition variations of the basic epoxy polymer in combination with each of
several curing agents were conducted. The resulting emulsion was analyzed through
laboratory tests to measure gloss value, drying time, hardness/flexibility, level of solvents, and
chemical and stain resistance. All test results were documented.
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Product coating characteristic criteria used in this project included but are not limited to:
1. The product will contain VOCs < 20 g/1.
2. The product will have a gloss value in the 90-100 range as measured on an 80
degree gloss meter.
3. The product will "dry to the touch" in 10 minutes or less and "dry to handle" in
IS minutes or less for temperatures in the range of 45 to 60°C with a relative
humidity not to exceed 80%.
4. The product will have a demonstrated pencil hardness of at least 2H.
5. The product will have a demonstrated chemical, water stain, and chip resistance
comparable to other products for the same general use.
Task 2 - Variations in pigmentation
An emulsion was formulated with white pigment for the best epoxy polymer/curing agent
ratios selected in Task 1. Laboratory tests were conducted to measure gloss value, drying
time, hardness/flexibility, level of solvents, and chemical and stain resistance. All test results
were documented.
Task 3 - Preparation of finished coating samples
The existing two-component spray application system developed by Binks Manufacturing Inc.
was modified and the application of the coatings was evaluated to determine if it meets the
production requirements of wood furniture manufacturers. The results are shown in Table B.
Task 4 - Market development
Several wood furniture manufacturers and coating suppliers were contacted to identify wood
coating concerns, current application methods, costs, and critical areas for product
improvements. Marketing information related to the wood coatings market was collected.
The market segments in turn are subsegmented into wood furniture, kitchen cabinets, new
case goods, plywood (hardboard), regenerated wood products, flat stock finishes, and specialty
finishes. This information was reviewed to establish what specific data still need to be
collected and how they should be used in structuring the planned market survey of wood
coating suppliers.
Two market development reports will be prepared to summarize how the new wood coatings
362
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address the concerns of the marketplace, potential cost benefits, and limitations.
4.0 RESULTS AND FUTURE DEVELOPMENT
Work on variations of the patented epoxy polymer in combination with different curing agents
was finalized (see Table C). The synthesis of the resin into a new resin was completed and
was followed by the emulsification of the product in water. Analysis was expended by
selecting those additional curing agents not previously evaluated but were known to be
sufficiently reactive to achieve proper film formation and acceptable properties. Each
resulting film is characterized as to its properties (see Table D).
Various formulations of curing agents in combination with the various epoxy polymers were
evaluated to precisely identify those combinations that yield the best overall coating
performance and meet the desired coating characteristic criteria (see Table D).
Table A. VOC content of wood coatings
SAMPLE DESCRIBED AS:
SOURCE:
ANALYTICAL
Volatile content
3792 (GC), and
ADHESIVE COATINGS CO.
PART B 65-99 (CLEAR)
PART A 76-64 (WHITE)
2755 Campus Drive, Suite 125
San Mateo, CA 94403
WORK PERFORMED, METHOD OF ANALYSIS, AND RESULTS:
by ASTM-D-2369-811, density by ASTM-D- 1475-60, water by ASTM-D-
calculations by ASTM-D-3960-81 Section 8.2.4.
VOCs content2
VOCs, g/1 (of coating) = <10
VOCs, g/I (of material) = <10
The Center will also develop a low/no VOC "sanding sealer" wood coating so that a complete
1 The detection limit for VOCs is 10 g/1.
2 The two products (76-64 and 65-99) were mixed 5 : 1 prior to actual analysis.
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low/no VOC wood coating system will be available for public use. The extra developmental
work will be focused on reformulating wood base coatings, determining performance
characteristics and conducting application and emission testing for a new fast drying, solvent
free wood sanding sealer.
Table B. Physical properties of applied finish
COLOR
Clear or pigmented white
SERVICE
TEMPERATURE LIMITS
-18 to 120° C (0 to 250° F).
May discolor over 60° C (140° F) after a long
period of baking
GLOSS
Clear coating - 90 @ 80° meter
Pigmented coating - 75 @ 80° meter
HARDNESS
Pass 2H pencil
FLEXIBILITY
Pass 3 mm (1/8 in.) mandrel bend on steel
IMPACT RESISTANCE
Direct - Pass 3 m/kg (60 in./lb)
Indirect • Pass 1.5 m/kg (30 injlb)
ADHESION
Pass Crosshatch 100%
STAIN RESISTANCE '
(After 1 hour of exposure)
Coating is resistant to:
Coffee
Grape juice
Mustard
Ketchup
Carbonated cola beverage
100 proof vodka
Shoe polish
Laundry spot cleaner
Detergent
1,1,1 trichloroethane
Acetone
Petroleum solvents
Ethyl alcohol
Cure conditions including curing rate, extended pot-life, and rheology modifications to include
use of thickeners in the formulation for adjusting the flow of coatings will be evaluated.
Both "clear" and "white" finished wet samples for emission testing will be prepared utilizing
a two-component variable ratio spray application gun.
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Table C. Physical properties (in the can)
APPEARANCE
VISCOSITY
PH
TYPE
DENSITY
SOLIDS
FLASH POINT
SHELF LIFE
VOC CONTENT
Milky white, single-phase, creamy liquid
Part A: 0.9 Pa.s (900 centipoise)
Part B: 0.9 Pa.s
5.5 to 7.5
Two components:
Part A - Epoxy emulsion
Pan B - Curing agent
Clear: 1030 g/1 (8.60 Ib/gal)
White: 1500 g/1 (12.5 Ib/gal)
50% by volume
over 150° C (300° F)
> 6 months
< 10.0 g/1 (0.1 Ib/gal)
Table D. Application properties
MIX RATIO
THINNING SOLVENT
CLEANUP
FILM THICKNESS
THEORETICAL COVERAGE
DRYING TIME @ 50° C
RECOATABILITY
Pan A - 5 parts
Pan B - 1 pan
Water
Warm soapy water
75-125 urn (3.0-5.0 mils) wet
40-65 urn (1.5-2.5 mils) dry
9 mVl (360 frVgal) @ 50 pm (2 mils)
To touch: 10 rnin
To recoat: 20 min
Tack free: 15 min
Full cure: 60 min
Very good
365
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366
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SESSION 9
AEROSPACE APPLICATIONS
PAPERS PRESENTED:
"Replacement of Chromated Epoxy Primers/Wash Primers for
Ground Support Equipment and Space-Related Flight Hardware"
by
Mark E. Lindsay
Lockheed Missies & Space Company, Inc.
Sunnyvale, California
'An Investigation of flexibility Test Methods for Low-VOC Aerospace Coatings"
by
Angela M. Brown
Boeing Defense & Space Group
Seattle, Washington
"Waterborne Maskant"
by
Mark D. Jaffari
Malek, Inc.
San Diego, California
"Low-VOC Organic Coatings for Commercial Aircraft Application"
by
T. D. Leland
C. M. Wong
Boeing Commercial Airplane Group
Materials and Processes Engineering
Seattle, Washington
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
Replacement of Chromated Epoxy Primers/Wash Primers for
Ground Support Equipment and Space Related Flight Hardware
Mark E. Lindsay
Lockheed Missiles & Space Company, Inc.
P.O. Box 3504
O/78-30, B/564
Sunnyvale, CA 94089-3504
INTRODUCTION
Hexavalent chromium is listed as a hazardous air pollutant (HAP) under
Section 112 of the Clean Air Acv of 1990. In 1990, Lockheed Missiles and
Space Co. (LMSC) took a proactive approach to eliminate/reduce the use of
chromate containing compounds. Compounds containing hexavalent
chromium are used as corrosion inhibiting pigments in paint primers such as
epoxy primers and wash primers.
LMSC uses several epoxy primers and wash primers that contain up to
50% by weight chromated compounds as pigments. The primers primarily
serve three functions. They (1) increase the compatibility between the substrate
and the topcoat, (2) improve adhesion, and/or (3) improve the corrosion
resistance of the substrate. Wash primers are used as a pretreatment for bare
steel, copper, nickel, titanium, and aluminum surfaces to promote adhesion
prior to priming where an immersion chemical treatment is not feasible. When
this study began, eight chromated epoxy primers/wash primers were identified
in use at LMSC (see Table I).
TABLE I - LMSC CHROMATED PRIMERS
SPECIFICATION
MIL-P-23377
LAC 37-4467
MIL-C-8514
DOD-P-15328
LAC 37-4850
MIL-P-85582
TT-P-1757
LAC 37-4698
DESCRIPTION
Epoxy primer
Chemglaze primer
Wash primer
Wash primer
Zinc chromate primer
Water reducible primer
Zinc chromate primer
Wash primer
CHROMATE CMPD.
Strontium chromate
Zinc chromate
Zinc chromate
Zinc chromate
Tine chromate
Barium/strontium
Zinc chromate
Zinc chromate
USAGE 1989-90
75 gal/year
48 gal/year
8 gal/year
Not used in 1990
Not used in 1990
6 gal/year
2 gal/year
2 gal/year
APPROACH
Epoxy Primers
The approach for replacing epoxy primers is illustrated in Figure I.
Chromate free epoxy primers were evaluated for the two major applications in
LMSC's Space Systems Division (SSD); ground support equipment (GSE) and
space related flight hardware (SRFH). The approach consists of identifying
candidates, screening the candidates and performing additional tests
depending on the application (GSE or SRFH). The requirements for the
screening tests are presented in Table II and the specific requirements for GSE
and SRFH are presented in Tables III and IV, respectively.
369
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Rgurel
Approach to Replace Epoxy Primers
PHASE I
IDENTIFY CHROMATE-FREE
PRIMERS
• VOC <340 g/1
• Chromate-free
• Non-toxic pigment
•Commercially Available
PHASE II
SCREENING PROCESS
TESTS
• See Table II
MATERIALS
• MIL-C-65285 polyurethane
• MIL-C-22750 epoxy topcoat
• TT-L-32 lacquer
I
PHASE HI
APPUCATION TESTS
SUBSTRATES
•2024 Al bare
•2024 Aldad bare
•2024 Al chem filmed
•6061 Al bare
•6061 Al chem filmed
•Cold relied steel bare
GSE Requirements
•See Table III
SRFH Requirements
•See Table IV
GSE = ground support equipment
SRFH = space related flight hardware
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TABLE II - SCREENING TEST REQUIREMENTS AND METHODS
TEST
Viscosity-initial
Viscosity-spray
Outgassing
Dry time
Appearance
Adhesion
Lifting
Knife test
Impact resistance
Water resistance
Salt spray
resistance
Filiform corrosion
resistance
Fluid resistance
Gloss
Volatile organic
content
REQUIREMENTS
Info only
Info only
Collected volatile condensable
material: 0.1% max.
Total mass loss: 1 .0% max.
Tack-free: Info only
Dry hard: Info only
Smooth and uniform. No runs,
sags, orange peel, wrinkling.
bumps, fisheyes, pinholes. craters,
blisters, grit, or seeds.
No lifting, peeling, or coating
separation
No lifting or film irregularity after 5
hours
No flake, chip, or powder
10% min. impact elongation
No softening, wrinkling, or
blistering
No blistering, lifting, or corrosion
0.25" corrosion max. from scribes
lines
Lubricating oil: No softening,
blistering, or adhesion losf
Hydraulic oil: No softening,
blistering, or adhesion loss
30 max.
340 g/I max.
METHODS
#4 Ford cup
#4 Ford cup
ASTM E 595
ASTM E 595
Visual
Visual
Visual
FTMS141,
Method 6301
Visual
FTMS141.
Method 6304
GE Impact tester
4 days in Ol water
at120F
Scribed, 1000 hours
in 5% salt fog
Scribed, 1000 hours
in 80% RH at 40C
Immersed for 24
hours at 250F
Immersed for 24
hours at 150F
60 degree gloss
meter
BAAQMD method
Table III - REQUIREMENTS FOR GSE
Test
5% salt spray resistance
Filiform corrosion resistance
Wet tape adhesion
Intercoat adhesion
(topcoats: MIL-C-85285, Am-E-Pox
Enamel and MIL-C-22750)
Requirement
1000 hours
1000 hours, 0.25 in max.
scribe line
lifting on
No lifting
No separation
371
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Table IV - REQUIREMENTS FOR SRFH
Test
Dry tape adhesion
Intercoat adhesion
(topcoats for flight hardware}
Outgassing
Coefficient of thermal expansion
(CTE)
Requirement
No lifting
No separation
TML:1.0%max.
CVCM:0.1%max.
similar to current primer
(LAC 37-4467 Che mg laze primer)
Wash Primers
Bay Area Air Quality Management District (BAAQMD) regulation changes
for wash primer VOC (780 g/l to 420 g/l) in 1991 prompted LMSC to investigate
replacement wash primers for GSE. A similar approach to the approach
described in Figure 1 for epoxy primers was used to replace wash primers. The
requirements for wash primers are listed in Table V.
TABLE V - WASH PRIMER REQUIREMENTS
Test
Dry time
Appearance
Wet tape adhesion
bare steel and aluminum
Compatibility with
primers (MIL-P-23377,
MIL-P-53030 and MIL-
P85382)
VOC
Requirement
Info only
Smooth, uniform no runs
No lifting, peeling or
separation
No intercoat adhesion
loss
420 g/l max.
Method
Visual
Visual
FTMS 141, Method 6301
Visual
»
BAAQMD Method 22 or
23
RESULTS
Epoxy Primers
Phase I. An industry search and literature review identified six potential
replacement primers which are chromate-free, have VOCs less than 340 g/l,
and are commercially available. The six epoxy primer candidates identified are
listed in Table VI.
TABLE VI - EPOXY PRIMER CANDIDATES
Manufacturer
Deft
DeSoto
Akzo
Lord Chemical
Savannah
Gavlon
Product Identification
44-R-8A/44-W-7 (MIL-P-53030)
PR-330/ACT-330
41407B534
K3803A
D-213 Industrial Red
9815-8509
Description
Water reducible
High solids
Ultra-guard high solids
Urethane, high solids
High solids
High solids
372
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Phase II. During the initial screening tests, it was found that the Lord Chemical
primer (K3803A) only had a pot life of 10 to 15 minutes. This candidate was
eliminated. The screening test results for the remaining 5 candidates are
presented in Table VII.
Phase III. The tests for GSE application were all included in the Phase II
testing, thus no additional tests were needed for this application. The test
results for the SRFH are presented in Table VIII.
TABLE VIII* - MIL-P-53030 PRIMER RESULTS FOR SRFH
Test
Dry tape
adhesion
Intercoat
adhesion
Outgassing
CTE,
um/m°C
•Testl
CTE,
um/m°C
•Test 2
Coating
primer
primer & A276
white PU topcoat
primer & Z306
black PU topcoat
pnmer
primer & A276
white PU topcoat
primer & Z306
black PU topcoat
pnmer
pnmer
Result
Deft primer
(MIL-P-53030)
Pass
Pass
Pass
TML: 2.5 - 2.9%
CVCM:0.15-0.35%
TML: 4.0 - 5.5%
CVCM: 0.01 - 0.08%
TML: 1.4 -4.9%
CVCM: 0.04 - 0.14%
ai = 29.2
«2 = 73.8
ai = 23.8
«2 = 675
9922 primer
(control)
Pass
Pass
Pass
TML: 2.0 -2.1%
CVCM: 0.04 - 0.05%
TML: 3.8 - 4.8%
CVCM: 0.02 - 0.03%
TML: 1.4 -2.7%
CVCM: 0.01 - 0.04%
ai = 40.7
-------
TABLE VII - SCREENING PROCESS TEST RESULTS
TEST
Viscosity-initial
Viscosity-spray
Oulgassing: CVCM
TML
Dry Time: Tack-free
Dryhard
Appearance
Lilting
Knife test
Impact resistance
Water resistance
Salt spray resistance
Filiform corrosion resistance
Fluid Resistance: Lube oil
Hydraulic oil
Gloss
Volatile organic content
Adhesion: (Wet Tape)
2024 A1 with MIL-C-5541, Cl. 1A
2024 Alclad. solvent cleaned
2024 Alclad, with TT-L-32 topcoat
6061 Al, solvent cleaned
6061 Al with MIL-C-5541, Cl. 1A
Steel, solvent cleaned
Steel, sandblasted
Adhesion: (DryTqpe)
2024 Al with MIL-C-5541, Cl. 1A
2024 Alclad, solvent cleaned
2024 Alclad, with TT-L-32 topcoat
6061 Al, solvent cleaned
6061 Al with MIL-C-5541, CM A
DEFT
26 seconds
26 seconds
0.073%
.92%
30 minutes
1.0 hours
Pass
Pass
Pass
30%
Pass
Pass
Pass
Pass
Fails
3 units
2800/1
Pass
Fails
Pass
Fails
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
DE SOTO
25 seconds
25 seconds
0.002%
3.86%
2.5 hours
3.5 hours
Pass
Pass
Fails
4%
Pass
Fails
Fails
Pass
Pass
15 units
339oyi
Fails
Fails
Fails
Fails
Pass
Pass
Pass
Fails
Pass
Pass
Fails
Fails
SAVANNAH
Too thick
19 seconds
0.07%
3.07%
60 minutes
2.5 hours
Pass
Pass
Pass
30%
Pass
Fails
Pass
Pass
Pass
0.9 units
471 g/l
Pass
Fails
Pass
Fails
Pass
Fails
Fails
Pass
Pass
Pass
Pass
Pass
GAVLON
Too thick
18 seconds
0.40%
2.73%
30 minutes
2.0 hours
Pass
Pass
Pass
20%
Pass
Pass
Pass
Pass
Pass
1.5 units
4010/1
Pass
Fails
Fails
Fails
Pass
Fails
Fails
Pass
Pass
Pass
Pass
Pass
AKZO
15 seconds
15 seconds
0.26%
5.10%
14 hours
22 hours
Pass
Pass
Pass
30%
Pass
Pass
Pass
Pass
Pass
29 units
287 o/t
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
-------
TABLE IX - WASH PHIMER WET TAPE ADHESION TEST RESULTS
Coating
Wash Primer
Den 46-W-4
MIL-C-8514
Primer
MIL-P-53030
MIL-P-23377
MIL-P-85582
MIL-P-53030
MIL-P-23377
MIL-P-85582
Topcoat
MIL-R-85285
MIL-R-85285
MIL-R-85285
MIL-R-85285
MIL-R-85285
MIL-R-85285
Substrate
Bare Steel
Pass
Fails
Pass
Pass
Fails
Pass
6061 Al
Pass
Pass
Fail
Fail
Pass
Fail
TABLE X - WASH PRIMER TEST RESULTS
Coating
Deft 46-W-4
Deft 46-W-4
Deft 46-W-4
Deft 46-W-4
MIL-P-53030
MIL-R-85285
Substrate
N/A
N/A
Steel
Steel
Test
Dry time
VOC
Appearance
Adhesion, FTMS
141, Method
6301 w/o cuts
Result
Tack Free: 30 min.
Dry hard: 1 hour
183g/L
Pass
Pass
375
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DISCUSSION
Epoxy Primers
The primary function of epoxy primers is to (1) increase its compatibility
between the substrate and the topcoat, (2) improve adhesion, and/or (3)
improve the corrosion resistance of the substrate. The process screening tests
include tests to verify that the primers will function as required, evaluate the
application characteristics (i.e. dry time, appearance) of the coating, and verify
BAAQMD VOC requirements are met. The process screening tests (see Table
II) were derived from MIL spec requirements for paint primers (i.e. MIL-P-23377
- Primer Coatings: Epoxy, Chemical and Solvent Resistant).
A major concern in using chromate-free primers is the potential toss of
corrosion resistance. Filiform corrosion resistance and salt spray resistance are
two tests that evaluate corrosion resistance. In filiform corrosion resistance,
primed and topcoated panels are "X" scribed, placed in concentrated
hydrochloric acid for an hour, and then placed in a chamber at 104F and 85%
relative humidity for 1000 hours. Filiform corrosion appears as threadlike
filaments initiating from the exposed substrate and spreading underneath the
coating. The test simulates damage to the surface of a piece of hardware and
how well the primer prevents further coating damage. In salt spray resistance,
primed panels are "X" scribed and placed in a 5% salt fog chamber. Salt spray
is intended to reproduce corrosion that occurs in salt spray conditions. MIL-P-
53030, Gavlon, and Akzo all passed both filiform and salt spray corrosion
resistance. Savannah passed filiform but failed salt spray resistance. The
DeSoto primer failed both of the corrosion resistance tests.
MIL-P-53030 had good wet tape adhesion on alodined aluminum and
bare and sandblasted steel. Akzo passed all the wet tape adhesion tests. Both
Savannah and Gavlon passed wet tape adhesion on alodined surfaces but
struggled on bare surfaces and sandblasted steel. DeSoto failed most of the
wet tape adhesions on both bare and alodined aluminum. All but DeSoto
passed all the dry tape adhesion testing.
MIL-P-53030's ease of application and one hour dry time help make it
practical for manufacturing to use. Akzo was also easy to apply but has a long
tack-free time (14 hours) and dry hard time (22 hours) which can be
inconvenient for manufacturing to use. The DeSoto primer was easy to handle
but was brittle, contributing to the aforementioned failures in adhesion. Both
Gavlon and Savannah handled adequately and had acceptable dry times but
both required significant solvent thinning to reach spray viscosity. The Lord
primer had a pot life of 10-15 minutes. Lord indicated that their K3803A primer
was designed for a two-component spray gun. Two feed lines separately pump
the two components together into a constantly agitated pot, and then feed the
mix to the spray gun to be applied to the surface of the part. This application is
not practical for LMSC so testing was halted.
The VOC was tested using BAAQMD Method 22 (Solvent based, less
than 2% by weight water) or Method 23 (Water based). MIL-P-53030. DeSoto,
and Akzo all were VOC compliant at application viscosity. Both the Gavlon and
376
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Savannah primers were designed as high solids but their vendors did not test
their VOC's according to the BAAQMD methods. For example, in Gavton's
case, they used theoretical solids instead of actual in calculating their VOC.
Ground Support Equipment. The MIL-P-53030 primer met all engineering
requirements needed for a GSE paint primer. MIL-P-53030 was compatible
with MiL-C-22750 epoxy topcoat, MIL-C-85285 high solids polyurethane, and
epoxy enamel used on GSE at LMSC. That makes it an excellent choice to
replace MIL-P-23377 high solids chromated paint primer and MIL-P-85582
water reducible chromated paint primer. Further testing of Akzo is warranted
but not a high priority due to its long dry time and the success of finding MIL-P-
53030. It is still being considered as a second chromate-free primer for GSE.
No further study was deemed necessary on Savannah, DeSoto, or Gavion
primers.
Space Related Flight Hardware. In Phase II testing, the MIL-P-53030 primer
results were encouraging, so it was evaluated for possible use on space related
flight hardware (SRFH). MIL-P-53030 was compared to the current high VOC,
chromated primer for SRFH, Chemglaze 9922.
Outgassing is one of the key requirements for a coating used in space
environments. When a coating is exposed to space vacuum environments,
some volatiles can condense on critical surfaces and interfere with performance
of optical or thermal control surfaces. ASTM E 595 is the standard method for
measuring outgassing in a vacuum environment. ASTM E 595 requirements for
Total Mass Loss (TML) and Collectible Volatile Condensable Material (CVCM)
are 1.0% max and 0.1% max, respectively. MIL-P-53030 by itself has CVCMs
ranging from 0.15% to 0.35%. When MIL-P-53030 is topcoated with A276 gloss
white polyurethane or Z306 flat black polyurethane the CVCM of the composite
films is consistently under 0.1% and the TMLs compare favorably with the
current Chemglaze 9922 system (see Table VIII).
Intercoat adhesion with the two different SRFH topcoats, A276 gloss
white polyurethane and Z306 flat black polyurethane, is important and MIL-P-
53030 has been found to be compatible with both.
Substrate adhesion to several different SRFH surfaces is also important.
Only dry tape adhesion is necessary as water and other weather considerations
are non-existent in space environments. MIL-P-53030 has demonstrated good
adhesion to alodined 6061 aluminum, bare 6061 aluminum, Dow 17 coated
magnesium, and abraded epoxy graphite.
The CTE of the two primers were compared in order to identify any gross
differences in thermal characteristics between the two materials. The CTE for
MIL-P-53030 primer compares favorably with that of the Chemglaze 9922
primer.
Further work includes outgassing rate studies and thermal cycling (-250F
to +250F).
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Wash Primers
After comparing the wet tape adhesion of the Deft wash primer and MIL-
C-8514 wash primer with different primers on different substrates (see Table IX),
it was noted that both the control (MIL-C-8514) and the Deft wash primer
performed erratically and did not meet the requirement consistently. Neither
MIL-C-8514 (Metal Pretreatment Coating Compound) nor DOD-P-15328
(Pretreatment Wash Primer - Formula No. 117 for Metals) specifications have
any wet tape adhesion or weathering test requirements. It was decided that the
wet tape adhesion requirement was not necessary.
It should be noted that all the wet tape adhesion failures for both MIL-C-
8514 and Deft were between the wash primer and the substrate. The Deft wash
primer demonstrated acceptable intercoat adhesion with three different primers.
Two of the primers, MIL-P-85582 water reducible, epoxy primer and MIL-P-
23377 high solids, epoxy primer, are chromated and have been replaced in the
SSD GSE paint processes specification by the third primer, MIL-P-53030 epoxy
primer.
The subsequent tests for the Deft wash primer (Table X) indicated that it
is an acceptable chromate-free replacement. The Deft wash primer passed
VOC, appearance, and adhesion tests. This adhesion test was a wet tape
adhesion with no cuts. The Deft wash primer is easy to apply and convenient to
use since a subsequent primer can be applied after an hour. Since it is VOC
compliant and performs very well with the GSE MIL-P-53030 primer, it was
implemented as the GSE wash primer for SSD.
CONCLUSION
Ground Support Equipment
Two epoxy primers, MIL-P-53030 and Akzo, were found that meet GSE
requirements. MIL-P-53030 primer has the advantage of a short dry time which
makes it convenient for manufacturing to use and it has been implemented.
Akzo is still under consideration but due to its long dry time and the success of
finding another successful candidate, there is not urgency to test further at this
time.
Space Related Flight Hardware
MIL-P-53030 has shown much promise as an eventual replacement for
use on SRFH. Further work includes outgassing rate studies, thermal cycling (-
250Fto+250F).
Wash Primers
The Deft wash primer met all the requirements of GSE wash primer.
Since it is VOC compliant and performs very well with the GSE MIL-P-53030
primer, it was implemented as the GSE wash primer for SSD.
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
AN INVESTIGATION OF FLEXIBILITY TEST METHODS
FOR LOW VOC AEROSPACE COATINGS
Angela M. Brown
Boeing Defense & Space Group
P.O. Box 3999 MS 82-32
Seattle, WA 98124
INTRODUCTION
Throughout industry, development work is currently underway to find low volatile organic
compound (VOC) containing alternatives to high performance aerospace coatings. Chemical
resistance and flexibility are two performance characteristics required of aircraft coatings.
Unfortunately, these two requirements trade off with each other - increasing one decreases the
other. Impact and mandrel bend tests are defined for the flexibility requirements in current
aerospace coating specifications. As low VOC alternatives are being formulated and evaluated, the
suitability of these test methods to represent the actual functional requirements of an aircraft in
service has been questioned. The relationship of the results of current flexibility test methods to
each other and to actual functional performance will be studied using a test set-up representative of
service conditions.
379
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ENVIRONMENTAL SIGNIFICANCE
In the course of developing environmentally compliant coatings, chemists and engineers are
forced to look to new binder technologies. Among the more promising new technologies at this
time are water-borne, high solids, ultraviolet (UV) curable and powder coatings. Mechanical test
methods are often used in aerospace specifications to assess coating performance. In this paper, a
mechanical test is a test that measures the performance of a coating, as compared to a test that
measures the physical properties of the material, such as the glass transition temperature.
Adhesion, abrasion resistance, flexibility, and hardness are examples of requirements where
mechanical tests are used. These test methods can be successfully used when measuring relative
performance of similar coating formulations. When used to assess the properties of a new
formulation, these mechanical test methods may not provide definitive results. If these mechanical
tests are used without good judgement, viable candidate formulations may be discarded as
unusable. During the course of developing environmentally compliant coatings, unnecessarily
limiting the number of viable alternatives would be unfortunate. A study of flexibility test methods
and their relationship to functional requirements in aerospace applications will provide data to
support engineering judgement
AEROSPACE REQUIREMENTS
Coatings used in the aerospace industry have a unique set of requirements. They must
withstand a variety of environmental conditions during flight, ground handling, storage, and sortie
and mission situations. They must also withstand extreme combinations of these environmental
conditions, such as high temperature and chemical exposure. Table I summarizes the common
environments and their potential detrimental effects l.
Environmental Condition
High Temperature
Low Temperature
Thermal Shock
Humidity Extremes
Low Pressure
Vibration
Liquids (fuel, water, hydraulic fluid,
solvents, lubricants)
Polluted Atmosphere
Ice, Hail, Snow
Fungi
Ozone
Sand, Dust
Solar Radiation
Effect
expansion of substrate
contraction of substrate,
embrittlement
physical stress
moisture absorption, embrittlement
outgassing
physical stress
chemical attack, softening,
swelling, blistering
degradation
erosion, moisture absorption
degradation
chemical attack, degradation
erosion
physical degradation, embrittlement,
discoloration
Table I - Environmental Conditions for Aerospace Coatings
The typical finish configuration on aluminum aircraft structure is an inorganic surface
treatment, one coat of corrosion inhibiting epoxy primer, and two coats of a polyurethane topcoat.
380
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Flexibility verses Chemical Resistance
In the course of the development of new, environmentally compliant coating materials for
use in the aerospace industry, the issue of flexibility requirements combined with chemical
resistance requirements is mentioned time and time again as a roadblock. Current coating
technology relies on controlling the extent of cross-linking that exists in the coating to achieve the
required flexibility and chemical resistance. However, increasing the cross-link density to enhance
chemical resistance is detrimental to the flexibility of a coating, while decreasing the cross-link
density to improve flexibility compromises the chemical resistance properties.
When the flexibility of a coating is considered independently as a mechanical property, the
actual relevant requirement in aerospace applications is that the coating not crack in service around
fastener heads, and at laps and at gaps in the structure. Flexibility is required to withstand the
relative motion between two separate but continuously coated pieces, such as structure and
fastener, due to vibrational and thermal stresses. One of the primary functions of aerospace
coatings is corrosion protection, and a break in the coating reduces its ability to protect the
substrate on which it is applied. Both requirements are vital to the successful high performance
aerospace coating formulation.
Resistance to a variety of different chemicals is also a fundamental requirement of these
coatings. These chemicals include fuel, hydraulic fluid and solvents.They may be encountered
during the assembly of aerospace hardware as well as in service. In service, coated surfaces will
be literally bathed in these substances. The chemical resistance of a coating can be tested directly
by immersing coated panels, by taping a saturated cloth onto coated hardware, or by rubbing a
saturated cloth back and form across the coating surface.
CURRENT TEST METHODS
Material specifications for coatings used in the aerospace industry typically require one or
more of four different types of tests to evaluate a coatings "flexibility". These four types of
mechanical tests are forward impact resistance, reverse impact resistance, room temperature
mandrel bend and low temperature mandrel bend. Other types, which are used occasionally and
will not be discussed in this paper, include free-film elongation and tensile strength.
Impact Resistance Test
The impact resistance test measures the ability of an applied coating to resist the effects of
an impact that occurs at a rapid rate. The forward impact resistance test places a coated panel into a
fixture. A known weight is dropped from various heights onto a rounded indenter resting on the
surface of the coated face of the test panel A reading of the highest value of inch-pounds (in-lbs)
at which the coating does not crack is obtained. The reverse impact test is similar, except the panel
is placed coating side down.
Mandrel Bend Test
Bend tests measure the size of the radius around which a coated panel can be bent before
cracking. The coated panel is placed into a fixture and is bent with a roller around either a
cylindrical or a conical mandrel. When a cylindrical mandrel is specified, the test
usually has a pass/fail criteria around a given mandrel radius. A conical mandrel has a radius that
goes from approximately two inches to one-eighth inch. In the conical mandrel bend test, a percent
elongation value is obtained by measuring the length of the crack from the small radius end. This
test is also performed at low temperature, typically at -65 °F.
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Problems
These typical test types are used both interchangeably and as measures of the separate
properties of flexibility and impact resistance. How the requirements are defined varies from one
specification to the next. For example, the forward and reverse impact resistance test appears in
various coating specifications under the name impact resistance, impact durability, impact
flexibility, and ambient flexibility, to name a few. This generates confusion as to what property is
actually being measured. The mandrel bend test does not evaluate the coating performance in a
situation similar to service; aerospace coatings in service do not undergo bending around tight
radii.
Mechanical tests that are used in specifications are typically quick, inexpensive and simple
to run. Often these tests are either pass/fall or have qualitative rather than quantitative results.
These mechanical tests are valuable as receiving and inspection, and quality control tools. These
types of tests can be successfully used when comparing, a set of similar materials. However, when
the test is expanded to compare two different types of materials, direct comparisons can no longer
be made.
Qualified coatings must maintain their properties while being subjected to extremes of
temperature and humidity, as well as chemical attack and solar radiation. Typically, the mechanical
tests are performed on freshly applied coatings. When qualifying new materials,however,some
specimens for the various flexibility tests are exposed to either accelerated or natural weathering
prior to testing. Allowing the test specimens to undergo weathering prior to testing is one way to
increase the severity and realism of these tests. However, it does not duplicate service conditions.
The problems with relying on these simple mechanical tests are compounded by the fact that the
material that is being worked with is viscoelastic in nature. That is, the coating's behavior changes
with temperature as well as with the rate of applied stress. All of these factors contribute to the
complexity of understanding how to properly use mechanical test data.
If new coating formulations perform marginally when subjected to these tests and are
compared to established coating technologies, they may be discarded as unusable. If these
formulations have greater stability of physical properties under service conditions, or have better
adhesion, they may in fact be viable for use in aerospace applications. Obtaining data will support
scientific judgement in these areas.
TEST PLAN
Objectives
The dilemma of chemical resistance verses flexibility and the question of proper application
of current test methods has been highlighted during the course of developing new coating
technology in the search for low VOC coatings. This has caused many coatings vendors to
question the requirements and the use of current flexibility test methods. While many of the
problems associated with the use of these test methods are intuitively apparent, no actual data was
found to address the vendors concerns. To begin to address the questions of the proper application
of existing flexibility test methods, a study of these methods was planned. In order to keep the
scope of the study manageable, it was decided that only a small set of variables would be
incorporated. The affects of conditions such as thermal shock or erosion will not be considered.
The following is a list of objectives around which this test was planned:
1) Obtain data comparing each of the four typical test methods to each other, using
rank correlation as the evaluation criteria.
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2) Develop and perform a test method that represents aerospace service conditions,
and compare the results to current test method results.
3) Use a designed experiment in order to minimize expense of test and to obtain
data on impact of components of coating system on test results.
4) Determine if further, detailed study of this issue is warranted.
Development of Representative Service Life Test. Coatings on aircraft are applied in a continuous
layer over an assembly of parts. These coatings must have the flexibility to withstand the relative
motion of these parts due to vibrational and thermal stresses. A test that would simulate this type
of service environment would require a stress be applied to a specimen configured such that there
would be relative motion between two parts. It was determine that a tension-tension fatigue test
performed on a fastened lap joint would provide this test scenario. Table n summarizes the test
set-up. The tension-tension fatigue test is a common test in the aerospace industry for evaluating
the mechanical properties of materials. For the purposes of this study, it provides the relative
motion and repetitive stress environment that is representative of the service conditions faced by
aerospace coatings. The test specimen, which is described in Figure 1, is made of 2024-T3
aluminum sheet fastened with fifteen countersunk-head hex-drive fasteners. The aluminum sheet
was surface treated in accordance with Mil-C-5541 - "Chemical Conversion Coatings for
Aluminum Alloys" - or Mil-C-8625 - "Anodic Coatings for Aluminum and Aluminum Alloys".
The specimens were assembled with fay surface sealant and the fasteners were wet-installed with
the same sealant. One coat of primer and two coats of topcoat were applied after assembly.
Test type
Max load
Max stress
Min stress/Max stress Ratio
Temp ./Humidity
tension-tension fatigue
15,000 and 18,500 Ib
13 and 15.9 ksi
.019
ambient
Table n - Summary of Test Set-up
In this structural fatigue test, each end of the specimen is clamped into the fixture and a load
is applied that places the specimen into tension. As the cycles of the test progress, the samples is
repeatedly placed into more and less tension. The load is never completely removed. Because the
sample is not symmetrical, the outside three rows of fasteners are placed into greater tension than
the center row.
o o o
o o o
o o o
o o o
000
Figure 1 • Representative Service Life Test Specimen Configuration
383
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Detailed Test Plan
The variables chosen for this designed experiment were (1) surface treatment, (2) primer
flexibility, (3) topcoat flexibility, and (4) weathering. Varying these four factors provides
information on the variety of different test configurations that may appear in aerospace coating
specifications. The addition of replicate specimens without primer completes the coverage of
potential specification configurations. While the test was designed around these four variables and
their interactions, the data presented in this paper examines only the first three. An analysis of a
three-factor subset of this test design will not yield information concerning interactions between the
factors. The complete analysis, incorporating data with all four of the variables, will provide
information on all of the possible interactions.
Design of experiments was used to develop the test matrix. The matrix describing the panel
configurations comprising a set is shown in Table III.
Run
1
2
3
4
5
6
7
8
Surface
Treatment
Mil-C-5541
Mil-C-5541
Mil-C-5541
Mil-C-5541
Mil-C-8625
Mil-C-8625
Mil-C-8625
Mil-C-8625
Primer
Flexibih'ty
high
high
low
low
high
high
low
low
Topcoat
Flexibih'ty
low
high
low
high
low
high
low
high
Weathered
no
yes
yes
no
yes
no
no
yes
Table m. Flexibility Requirement Test Matrix
The test begins with an evaluation of the test methods themselves and yields data on how
well the test results for each test method correlate with each other. Seven sets of runs were
performed using 4 x 6 x 0.020 inch aluminum panels, with four replicates of each. These seven
sets include configurations with and without primer. The four flexibility test methods chosen for
this study are forward impact, reverse impact, room temperature conical mandrel bend and low
temperature conical mandrel bend.
The coatings selected for this study of flexibility test methods are shown in Table IV.
Both of the high flexibility choices claim to have sixty percent elongation when tested with a G.E.
impact tester and both of the low flexibility coatings claim twenty percent elongation.
Coating
Primer
Topcoat
High Flexibility
Koroflex
Gloss MIL-C-83286
Low Flexibih'ty
MIL-P-23377 Class 1
Flat MIL-C-83286
Table IV. Coatings Selected for Flexibih'ty Test Study
A tension-tension fatigue test of a fastened lap joint was chosen to represent service
conditions. The finish configurations defined in the test matrix (see Table HI) were applied to this
lap-splice fatigue specimen. The mechanical test resulted in data on the number of cycles to onset
of cracking. The data generated in this study will be analyzed statistically, looking at the finish
configuration as a system as well as at the individual finish components.
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DATA AND RESULTS
Analysis Methods
Based on the use of a designed experiment, the individual contribution of each of the three
factors - surface treatment, primer flexibility and topcoat flexibility - on the performance of the
tested panels can be determined statistically. The results of this analysis can be seen graphically in
figures 2 through 6. Table V provides information about the codes used on the x-axis of these
charts.
Code Letter
A
B
C
D
E
F
Finish Used
Mil-C-5541
Mil-C-8625
Low Flexibility Primer
High Flexibility Primer
Low Flexibility Topcoat
High Flexibility Topcoat
Table V - Explanation of Codes Used in Figures 2 Through 7.
Impact Resistance Test Results
Figures 2 through 5 show the results of a statistical analysis of the results of impact testing.
This analysis shows the contribution of each of the three factors to the results obtained during the
test It does not account for interactions. The analysis of the topcoat used is confounded with the
interaction between the surface treatment and the primer. Once the entire test matrix, as shown in
Table HI, is complete and analyzed, the information about the contribution of all interactions will
be obtained.
The forward impact test results shown in Figure 2 show that either the topcoat or the
surface treatment/primer interaction has the most significant contribution to the test results.
Because the effects of the surface treatment and the primer do not appear to be significant, it may
be assumed that this contribution is in fact attributed to the topcoat The reverse impact test results
shown in Figure 3 show a significant contribution to the test results by both the primer and the
topcoat Therefore, the possibility of a strong surface treatment/primer interaction cannot be
discounted.
Test panel configurations without primer were also tested. Figure 4 shows the results of
the forward impact test Neither the topcoat nor the surface treatment had a significant contribution
to the test results. The results of the reverse impact resistance test on panels without primer is
shown in Figure 5. These results clearly show that the topcoat properties had the more significant
contribution to the test outcome.
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Forward Impact Resistance
Figure 2 - Forward Impact Resistance Tests Results - Factor Effects
(see Table V)
Reverse Impact Resistance
A B
Figure 3 - Reverse Impact Resistance Test Results - Factor Effects
(see Table V)
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Forward Impact Resistance
(without primer)
T 45
A B E F
Figure 4 - Forward Impact Resistance Test Results - Factor Effects WITHOUT
Primer (see Table V)
Reverse Impact Resistance
(without primer)
9> 35
A B
Figure 5 - Reverse Impact Resistance Test Results - Factor Effects WITHOUT
Primer (see Table V)
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Conical Mandrel Bend Test Results
All of the panels tested in the room temperature conical mandrel bend tests passed without
any cracking. Those tested at the low temperature of-65 °F did have some failures, to which a
percent elongation value could be assigned No quantitative values could be assigned to those that
passed. Because of this, the same type of analysis that was done on the impact resistance tests and
the service life test could not be done on the mandrel bend data. Additionally, the two
configurations that experienced failures both had inorganic surface treatments in accordance with
Mil-C-5541 and were primed with the low flexibility primer. In all of the failures, the cracks were
accompanied by significant loss of adhesion of the surrounding coating. The disbond, in every
case, occurred between the conversion coating and the substrate. This may be due to inadequacies
in the applied surface treatment
Representative Service Life Test Results
Two replicates of each of the four configurations were fabricated for fatigue testing in this
study. A steep learning curve was experienced during the testing of the first set of replicates,
which was performed at a maximum load of 18,500 pounds. Because this type of test had not
been performed before, no experience was available concerning when to expect the first cracks.
An estimate was made that the first cracks would appear around one thousand cycles. This was a
poor estimate. Actual first cracks appeared before five hundred cycles. Consequently, inspections
for cracks were not made at the necessary cycle intervals to obtain differentiation in the data on the
first four specimens. Additionally, it was determined that decreasing the load on the parts would
create greater spread in the data. The second set of replicates was run at a lower load of 15,000
pounds and inspections for cracks were taken every ten cycles during the beginning of the test
Data points were taken at the number of cycles when cracks around three fastener heads were
observed. This data is shown in Table VI and Figure 6. This data is based on only one replicate,
so little confidence may be placed on the statistical analysis. Additionally, one of the
configurations performed much better than the other three, so that single data point distorts that
data shown in Figure 6. The data did, however, illustrate a significant difference between the
performance of each of the four different test configurations.
Run
Configuration
(see Table ffl)
1
4
6
7
Cycles to Onset
of Cracking
50
10
500
30
Table VI - Raw Data for Representative Service Life Test
In all cases the cracks began around the tops of the fastener edges in the top row of
fasteners. Once the cracks were initiated at the top of each of the fifteen fastener heads, crack size
did not change significantly over the next several thousand cycles. In some cases, bubbles in the
coating appeared and grew at the edge of the fastener heads. These bubbles were due to loss of
adhesion without a break in the film. In other cases, the fastener rotated significantly in the hole
while cycling, causing a twisting and stretching effect around the edges of the'fastener heads. In
these cases, the coating eventually tore with jagged edges. While testing the specimen with the
configuration of low flexibility topcoat over high flexibility primer, it was observed that only the
topcoat cracked. After ten thousand cycles, all but a few of these cracks continued to show primer,
intact, under the topcoat crack. All of the other test configurations cracked through the topcoat and
primer from the outset
Joo
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Cycles to Onset of Cracking
A B
C D
E F
Figure 6 - Representative Service Life Test Results - Factor Effects
(see Table V)
Comparison of Test Methods
Due to the small number of test configurations, an absolute correlation analysis was not
performed at this time. This type of correlation will be performed after data is obtained for the
entire test matrix (see Table El). Instead, the data has been analyzed by ranking the results of each
test and comparing these rankings. This ranked data is shown in Table VTJ.
Run*
1
4
6
7
RANK
Forward
Impact
With
3
2
1
4
Reverse
Impact
3rimer
3
2
1
4
Forward
Impact
Reverse
Impact
Without Primer
2
4
1
2
4
2
1
4
Low Temp
Bend
3
4
1
1
Service
Life Test
2
4
1
3
Table VII - Ranked Data Comparison Between Test Types
The averaged raw data is shown in Table VTA. Each entry in this table is the arithmetic
mean of four replicates.
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Run*
1
4
6
7
AVERAGED RAW DATA
Forward"
Impact
With!
46 in-lb
54 in-lb
56 in-lb
40 in-lb
Reverse
Impact
^rimer
32 in-lb
40 in-lb
46 in-lb
17 in-lb
Forward
Impact
Reverse
Impact
Without Primer
51 in-lb
50 in-lb
61 in-lb
51 in-lb
28 in-lb
46 in-lb
57 in-lb
28 in-lb
Low Temp
Bend
5% elong
>17%
>17%
4% elong
Service
Life Test
50 cycles
10 cycles
500 cycles
30 cycles
Table Vm - Averaged Raw Data for All Tests
FUTURE WORK
The effort to complete the gathering of data in accordance with the test matrix shown in
Table in is ongoing. Replicates of all of the test configurations for this test plan are currently
undergoing accelerated weathering. The one exception is the lap-splice fatigue specimens. These
specimens are large and bulky and will be difficult to handle in existing accelerated weathering
equipment. Due to lack of available funds, no additional replicates of the tension-tension fatigue
test configurations already tested will be evaluated. Once the entire data set is gathered, a more
rigorous statistical analysis, examining main factor effects as well as interactions, will be
performed. The results of this analysis will provide a more substantial comparison of the results of
the different test methods and will indicate whether additional testing, incorporating more
complexity of variables, is warranted.
DISCUSSION AND RECOMMENDATIONS
Impact Resistance Test
An examination of the averaged raw data in Table Vin shows a greater data spread in the
reverse impact resistance test than in the forward impact resistance test It also demonstrates that
the reverse impact test is a more severe test than the forward impact resistance test This indicates
that the reverse impact resistance test is the better choice when comparing different finish
configurations. This is particularly true when comparing adjustments of the same basic coating
formulation. The possible existence of a strong surface treatment/ primer interaction suggests that
adhesion plays a role in the performance of a coating configuration in the reverse impact resistance
test.
The topcoat flexibility had the most significant impact on the test results obtained in the
forward impact resistance test on the configurations used in this study.
Conical Mandrel Bend Test
The type of failure observed on those configurations that cracked during the low
temperature mandrel bend test suggests adhesion problems resulting from poorly treated
substrates. Each of these panels were treated with a chemical conversion coating. However, all of
the panels that received this treatment did not fail. Those that failed were the ones that were coated
with the low flexibility primer. This suggests both a surface treatrnentfrrimer interaction and
process problems with the chemical conversion coating. Additional replicates of this test will be
run on freshly treated panels in order to further evaluate this finding and ensure that adequately
processed panels have been used. Completion of data gathering for the entire test matrix will also
provide information on the significance of a surface treatment^>rimer interaction.
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The fact that there were so few failures in this test suggests that the conical mandrel bend
test can be successfully used as an indicator of gross problems, but will not provide sound data on
which to base fine comparisons. The low temperature mandrel bend test will be useful when
screening prototype coatings. Performing the mandrel bend test at room temperature does not
appear to be a useful test on the type of coatings that are typical in the aerospace industry.
Representative Service Life Test
Data on the number of tension-tension fatigue cycles to the onset of cracking of the coating
around the fastener heads of a lap-splice specimen can be successfully obtained The results,
shown in Table Vffl, show differentiation in the test results from one test configuration to another.
It is recommended that future tests of this type be run at lower loads in order to further spread that
data. The tests should be stopped and inspections made every ten cycles during the beginning of
the test until greater experience is obtained to predict failure points. Multiple replicates, if they do
not indicate significant variability, will also provide greater statistical confidence in the test results.
A reliability-based analysis, examining the fraction failed as a function of the number of cycles,
may also provide useful information.2
Comparison of Test Methods
The six tests that illustrated a difference between the performance of each of the different
test configurations consistently ranked the same high flexibility primer/high flexibility topcoat
configuration as the highest performer. Unexpectedly, the low temperature mandrel bend test
revealed the low flexibility primer/low flexibility topcoat configuration as a high performer as
well. All of the other five tests ranked this configuration low, with the exception of the forward
impact test without primer, which is discussed below. It appears that adhesion may play a
significant role in the performance of panels during this type of test Completion of the entire test
matrix and the performance of confirmation runs may shed more light on this phenomenon.
It appears that the forward impact resistance test performed on panels without primer yields
data whose ranking is inconsistent with the test on panels with primer. A closer examination of the
averaged raw data shows that three of the configurations actually yielded essentially the same
results. Therefore, there is no inconsistency.
A meaningful comparison of ranked results shown in Table Vm for each of the three
mechanical tests to the results obtained in the representative service life test cannot be made
because the fatigue test data includes no replication. It appears, however, that the test does provide
data that will differentiate between the performance of different coating configurations. Performing
repeats of the test runs will provide a data set that could be statistically analyzed, resulting in more
definitive results.
SUMMARY
Properly utilized, the mechanical test methods discussed in this paper can be valuable when
comparing the performance of similar coating formulations. In the course of developing new
coating technologies for environmental compliance, these tests will be relied upon as well.
Evaluation of mechanical test results, when comparing different coatings, should not be done
literally but should incorporate sound scientific judgement. The data presented in this paper and
that will be obtained during this study will provide additional basis for informed coating selections.
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ACKNOWLEDGEMENTS
The author wishes to acknowledge the valuable contributions of the following persons:
Marie Jorgensen Mark Foster
Kenny Downs Jim Gertis
Mark Parsons Mike Wagoner
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References
1. The Boeing Company. Environments/Environmental Protection. Boeing Design Manual
- 7180 Revision A. Seattle, Washington, 1990. 15 pp.
2. Martin, J.W. Service Life Prediction for Coating Systems. In: Proceedings of Short
Course in Accelerated and Natural Weathering Techniques for Coatings and Polymers, The
Kent State University Chemistry Department and Portage Technical Consultants, Inc.
Kent, Ohio, 1992.
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
WATERBORNE MASKANT
Mark D. Jaffari
Malek, Incorporated
4951 Ruffin Road
San Diego, CA 92123
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INTRODUCTION
Temporary protective coatings or maskants are heavily
utilized in aerospace chemical processing operations. The
purpose of a roaskant is to provide protection to aerospace parts
and assemblies during chemical and mechanical fabrication
operations. Operations such as chemical milling, anodizing,
painting, routing and bonding all reguire use of maskants to
protect either the whole part or selected portions of the part
from the chemical attack or mechanical damage.
These naskants can be of a solid form like tapes or rubber
plugs, but they are more generally applied as liguids (like
paints) which, when dry, conform to the contour of the part and
are manually peelable after the processing is completed.
Traditional maskants have been rubber-based and require the
use of chlorinated or aromatic solvents as the liquid diluent.
Although successful in performance, these traditional
solventborne maskants are highly toxic and have been the major
source of air pollution from aerospace chemical processing
factories. To combat this problem various approaches have been
taken to either put pollution control devices onto the liquid
maskant application equipment or to replace the solventborne
maskants with less toxic and minimally polluting waterborne
alternatives.
This paper discusses the chemical nature and challenges of
successfully developed waterborne maskants. Current products
produced by Malek, Incorporated which are on the approved
specification lists of major aerospace companies are described.
Details of the environmental benefits and manufacturing process
advantages which result from the implementation of waterborne
maskants are given. The economic considerations and pollution
savings are described for two major aerospace processing
factories located in the San Diego area.
ENVIRONMENTAL CONCERNS
Solventborne maskants are formulated in such a way as to
dissolve water insoluble polymers. Solvents such as
perchloroethylene, toluene and 1,1,1 trichloroethane are the most
commonly used for this purpose. Although these solvents do
dissolve the polymers, they must be used in a weight ratio of
solvent to polymer of much greater than 1 to get proper flow
characteristics. Therefore, solventborne maskants contain from
.50 to 80 percent solvent which evaporates upon drying. All of
these solvents are toxic to humans and the ecosystem in terms of
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toxic air contamination, ground/soil poisoning, inhalation and
transdernal absorption.
There are several local and federal regulatory agencies
which control the of use and emission limits from maskant
operations. Local air pollution control districts have rules
which specifically call out the allowable solvent content and/or
emission control efficiencies for aerospace maskant operations.
The Environmental Protection Agency has also classified all of
the above mentioned solvents as Hazardous Air Pollutants (HAPs).
The Occupational Safety and Health Agency has set ever decreasing
exposure limits for workers using these products. Public
awareness of this has increased community concerns over companies
involved with solventborne maskants. Companies may be required to
do assessments of the health effects to the surrounding community
resulting from their use of solventborne maskants. Finally,
federal excise taxes are also being charged to consumers of these
toxic solvents.
With all of this pressure being brought to bear on the usage
of solventborne maskants, the industry is actively seeking
alternative products.
SOLVENTBORNE AND WATERBORNE CHEMISTRY
The preferred alternative to minimize the many difficulties
associated with the use of solventborne maskants has been to find
low toxic air contaminant alternatives. In order to retain the
good performance characteristics of the solventborne maskants,
waterborne latices have been developed which are lower molecular
weight, water dispersible counterparts of solvent-dilutable
polymers. However, the emergence of these latices being
commercially available only partially solves the problem, leaving
many challenges to formulate a useful maskant.
Chemically, solventborne maskants are simple to understand
and forgiving in nature. Large molecular weight polymers are
used which generally are soluble in a variety of solvents. These
large molecular weight polymers have sufficient chemical
resistance "as is" so no chemical curing is required when the
film dries. This contrasts with waterborne latex polymers which
are of a smaller molecular weight and need to be cured or cross-
linked with heat and/or additional chemical additives to achieve
the desired chemical resistance and strength.
The other challenges have to do with the inherent
differences between solvents and water. Solvents have generally
low surface tension compared with water, therefore more care in
handling must be taken to avoid bubbles or foam in the waterborne
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maskant formulation. If the waterborne maskant formulation is
frozen, it cannot be reconstituted by thawing out as can be done
with solventborne maskants. This is due to the fact that latices
are emulsions and the emulsion will generally not survive the
shock of freezing. Water also supports bacterial growth and
corrosion reactions on metal, so additives must be introduced to
eliminate or control these phenomena.
Successful waterborne maskant formulators must consider
these effects and have them addressed in their products.
MALEK'S WATERBORNE MASKANT LINE
Since 1988, Malek, Incorporated has successfully formulated
waterborne maskants for aerospace chemical processing industries.
An overview of Malek's current products are listed below.
PRODUCT
EMISSIONS* MAIN INDUSTRIAL
CONTENT USE
AEROSPACE
COMPANIES
CAX-100-LA
CAX-177
CAX-200+
MBP-100
70
70
70
20
Electroplating,
Chemical Milling
Boeing, Pratt & Whitney
McDonnell Douglas,
Kelly AFB, Caspian Inc.
Chemical Milling Boeing, Caspian Inc.
Chemical Milling,
Anodizing
Alenia, Italy, McClellan
AFB, Caspian Inc.
Plating, Anodizing General Dynamics Convair
(McDonnell Douglas), Prat
& Whitney, Kelly AFB
*In grams solvent per liter of coating
Malek's waterborne maskants have been used on production
hardware since 1988 by Caspian Inc. in San Diego where they were
pioneered for applications in chemical milling. Inherently low
in solvent content and high in solids content these products all
offer dramatic reductions in air emissions created when compared
with their solventborne counterparts. As an example, the typical
solventborne product contains 1200 grams of solvent per liter of
coating at 20% by weight solids. The CAX products contain 70
grams of solvent per liter at 48% by weight solids. This results
in a 95% reduction in solvent emissions per unit area masked.
Malek's products are also applied in the same manner as with
solventborne maskants, using conventional spraying, dipping and
pre-mask cleaning techniques.
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As you can see, Caspian Inc.'s early success inspired many
other aerospace chemical processing companies to implement this
technology. Although this industry is traditionally very
conservative relative to changing processing chemicals, these
products have proven themselves to be capable of meeting the
strict requirements.
IMPLEMENTATION CASE STUDY: CASPIAN INC.
Caspian Inc. has operated an aluminum, titanium and steel
chemical milling plant for over 25 years in San Diego,
California. As a major subcontractor for the aerospace industry,
Caspian Inc.'s chemical milling processes are approved by over
twenty companies world wide, including Boeing, British Aerospace,
Fokker (Holland), Grumman, Lockheed, Martin Marietta, McDonnell
Douglas, Northrop, Rockwell, SAAB (Sweden), Short Brothers
(Ireland), and Teledyne Ryan, to name a few.
Caspian Inc. recognized early on that the perchloroethylene-
based maskant they were using would have to be replaced or be
retro-fitted with a very expensive solvent capture system to
recover greater than 90% of the emissions.
An economic analysis showed that the solvent capture system
would cost greater than two million dollars to install and carry
with it high operating and maintenance costs. Caspian Inc. also
realized that even with this system, they would still be exposing
the workers to perchloroethylene and the community would still
have the risk of fugitive emissions as well as a potential gross
emission if the recovery equipment were to fail, even
momentarily. By working closely with Malek, Caspian Inc.
examined its chemical milling process and current maskant
application requirements and they successfully replaced their
maskant operations with CAX-100-LA. They maintained all of their
customer approvals and process profitability while reducing their
emissions from maskant operations by over 95%.
The transition from a solventborne maskant process to the
CAX process was remarkably straight forward. The main adjustment
made by Caspian Inc. was to modify their maskant drying and
curing process. Since solvents are much more volatile than
water, it was not previously necessary for Caspian Inc. to use
ovens or forced drying equipment. The new waterborne process
requires that some provisions be made for drying the water.
These provisions involved the purchase of portable heaters, a
refurbishment of their existing oven and a minor adjustment to
the normal process scheduling to allow this drying to occur.
Although these changes cost Caspian Inc. capital and operating
dollars (approximately $30,000 for the heating equipment and 8
KWH of power) they were nearly insignificant when compared with
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over $2,000,000 in capital and at least 210 KWH operating cost
for the solvent capture system.
Additionally, Caspian Inc. has achieved pollution banking
credits of over 106 tons of VOC per year, which were awarded to
Caspian Inc. as they decreased their air emissions well in excess
of their currently permitted amount. These credits are a
tangible financial asset for Caspian Inc. and they are valid as
long as Caspian Inc. remains in business. Caspian Inc.'s
community image is improved and they are receiving a wealth of
positive publicity from environmental groups as well as customers
who prefer that their work be done in the most environmentally
conscious manner.
CASE STUDY: GENERAL DYNAMICS CONVAIR
General Dynamics Convair (GDC) has been in San Diego for
over twenty years performing a wide variety of chemical
processing, design and assembly of aerospace vehicles. In
particular, GDC is a source of a section of fuselage of the
McDonnell Douglas MD-11 aircraft. In the processing of this
fuselage, a large quantity of the parts go through a chemical
anodization process to promote paint adhesion to the interior's
surface. The exterior of these polished aluminum skins are
protected with maskant to prevent anodization of the exterior.
San Diego Air Pollution Control District Rule 67.9 requires that
by July 1, 1993, the maskant in this operation must have a VOC
content of 250 grams per liter (less water and exempt compounds)
or that an emissions control device must be installed to capture
at least 90% of the solvent.
Similar to Caspian Inc.'s situation, GDC had an existing
facility which would have been very expensive and technically
difficult to retro-fit with solvent capture equipment. Their
current spray booth was manually operated with airflow, humidity
and temperature control. They did not normally oven cure their
solventborne maskant, but they normally did allow the parts to
completely dry in the spray booth (taking about one hour after
all the spray coats are applied). Beginning in early 1992, GDC
research personnel began testing of Malek's products for this
process. The key specification factors involved the ability to
resist all process solutions, no damage to the appearance of the
highly polished aluminum, and easy manual peeling of the coating
after anodization. GDC identified MBP-100 as the best waterborne
alternative. Over thirty test pieces were run in GDC's production
tanks to choose the coating and to determine the parameters, such
as; required thickness, fluid viscosity, drying and curing times
for optimum operations. By the middle of 1992, GDC had decided
to go with a waterborne product in their current facility. Their
facility engineers designed a simple oven to dry and cure the
parts. This oven was placed onto existing floor space. No
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modifications to the spray booth or spraying equipment were
required. In late January 1993, the oven was installed and the
first production parts were successfully produced at GDC using
MBP-100.
Since then, GDC has stopped all purchases of solventborne
maskant (1200 g/1 emissions) and is using MBP-100 in its place,
almost six months ahead of the required compliance date.
MBP-100, having only 20 g/1 solvent content, saves over 98%
on the emissions in every day use. Their spraying equipment can
be cleaned with water and they do not need to add pure
perchloroethylene to keep their maskant thinned.
The early reports from GDC are all positive. They have the
performance they require, a competitive flow time, hugh pollution
reductions and the workers are not exposed to highly toxic
perchloroethylene.
CONCLUSION
Waterborne maskants for aerospace chemical processing do
currently exist. These products cover the complete gambit of
maskant utilization requirements. The fact that alternative
technology does indeed exist is further verified by the fact that
the local air pollution control district has recommended Malek's
CAX waterborne maskant as best available control technology.
The option of conducting a solventborne maskant operation
under the umbrella of a tightly-controlled solvent capture system
has many disadvantages. These machines are very expensive to
purchase and operate. They can contaminate the water which is
used in the recovery process and their very intense energy
requirements create increased pollution at the power plant.
Process flexibility is also compromised with a solvent
recovery system in that the parts, when wet with solvent, must
remain inside the device (a large, tightly-controlled building
full of concentrated toxic vapors) until the solvent has
completely evaporated. This requirement severely constrains
part-flow time. All maskant operations must be halted if this
device has any mechanical problems.
Waterborne maskants alleviate all of these problems while
introducing very few negative features, such as drying time,
which can be easily overcome with conventional technology. In
general, aerospace processing companies using maskants have a
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large degree of flexibility as to what products are used in-
house. Maskants do not fly-away with the airplane, and most
tines the individual companies themselves specify which products
are used.
As can be seen by our wide ranging customers and processing
applications list, many key companies which have been faced with
the increasing environmental and health concerns have already
implemented these and other waterborne maskant products. This
number of companies is increasing dramatically, and waterborne
maskants are now available from vendors of solventborne products.
We at Malek, Incorporated truly feel that this can be a case
where the industry acts with commitment and innovation to
economically operate in a less polluting fashion.
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
Low VOC Organic Coatings for Commercial Aircraft Application
Authors:
Address:
T.D. Leiand. C.M. Wong
Materials and Processes Engineering
Boeing Commercial Airplane Group
P.O. Box 3707, MS 73-40
Seattle, WA 98124-2207
ABSTRACT
In response to the implementation of the 1970 Clean Air Act smog reduction
requirements by state and local environmental regulatory agencies, over 300 low
VOC (Volatile Organic Compound) paint formulations have been evaluated since
1985 by Boeing for use on commercial aircraft. These formulations have been
state-of-the-art low VOC coatings based on (1) exempt solvent (methyl
chloroform), (2) high solids, (3) water reducible, (4) powder, and (5)
electrodeposition technologies.
Working closely with aerospace coatings suppliers, Boeing has achieved
significant progress in the development and qualification of low VOC organic
finishes, including corrosion resistant primers and decorative enamels used on the
interior as well as on exterior components of our aircraft. Incorporating these new
paints into our manufacturing processes, and those of our subcontractors is
helping to reduce smog-forming emissions from aerospace facilities. Development
efforts are continuing on low VOC coatings that can be used to replace the current
(1) decorative paint system for interior plastic surfaces, (2) fuel tank primer, (3)
flexible corrosion inhibiting coatings for in-spar areas of the wings, and (4) low
VOC chromate-free primers for non-metallic composites and metallic surfaces.
403
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BACKGROUND
The Clean Air Act of 1970 and implementation of its requirements by local
environmental agencies such as the South Coast Air Quality Management District
(SCAQMD) in the Los Angeles basin has posed a major challenge to both paint
manufacturers and users. The major impact on coating of commercial airplanes
was not felt until SCAQMD Rule 1124 mandated use of 350 g/l max. VOC primers
by January 1, 1988 and 420 g/l max. VOC topcoats by July 1. 1990 for
aerospace manufacturers in its jurisdiction1. This had a very significant affect on
Boeing commercial airplane manufacturing operations since hundreds of Boeing
subcontractors are located in the Los Angeles area.
Similar requirements were also soon adopted by other environmental
agencies such as those located in San Diego, San Francisco, Houston, Philadelphia,
Wichita and Seattle. For the Seattle area, Puget Sound Air Pollution Control
Agency (PSAPCA) Regulation II is requiring use of low VOC primers and topcoats
for coating the interior fuselage areas of airplanes by January 1, 1994.
Significant investment in alternative materials development began in the mid
1980's, motivated by the company's desire to reduce use of VOC's in materials
rather than relying solely on the use of control and capture technology. Use of
control and capture technology requires very high capital investment as well as
significant recurring maintenance costs including the cost of disposal of collected
hazardous materials. Working with coating suppliers to develop, wherever possible,
low VOC coatings that would perform equal to or better than the conventional
primers and topcoats for commercial airplane application was considered to be the
most environmentally sound and cost effective approach.
STATE-OF-THE-ART LOW VOC TECHNOLOGY
Several low VOC coating technologies were potential approaches to achieve
lower VOC coatings. The following is a list of the these technologies including
their advantages and disadvantages.
o 1,1.1 -TCA Exempt Solvent 1,1,1 -Trichloroethane (1,1,1 -TCA, also called
methyl chloroform) is considered to be non-
photochemically reactive and exempt from VOC
consideration by most regulatory districts. Since
it is an organic solvent, 1,1,1-TCA is easier than
water to use as a diluent in formulating coatings.
These coatings have drying and application
characteristics similar to conventional coatings.
However, 1,1,1-TCA has been identified as an
upper atmospheric ozone depleter and will be
phased out of production by 1996.
404
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o High Solids
o Water Reducible
o Waterborne
o Powder
o Electrocoating
Use of lower molecular weight resin is often
necessary in order to maintain proper application
viscosity with large reduction of VOC's in the
coating formulation. Longer dry times, shorter
pot lives and thicker films per coat are usually
observed with high solids formulations.
One successful approach has been based on a
modified polyamine and epoxy resin system which
has been made water reducible with the addition
of a nitroparaffin as solvent2. This type of
dispersion has demonstrated drying and application
characteristics similar to conventional paint.
However, it does require careful and gradual water
reduction after the base and catalyst are mixed to
secure a stable dispersion with proper viscosity.
It has shorter pot life and shelf lives than the
comparable conventional coatings.
These coatings are water based dispersions that
include water in either the base or catalyst or
both and would usually require no further water
additions. This is a relatively new development
and has the potential advantages of increased pot
life and easier mixing compared to water reducible
coatings. Whether they can meet commercial
aircraft performance requirements has yet to be
verified.
These are nearly 100% solids coatings emitting
little or no VOC. The current state-of-
the-art powder technology typically requires a
minimum 250 F bake. Exposing some aluminum
alloys to 250 F may have an adverse effect on
their mechanical properties. In addition, this
technology is applicable only to detail parts and is
more difficult to get smooth aesthetically
acceptable coatings.
This primer technology can offer very low
VOC emissions, uniform film thickness and can
incorporate the coating operation into a tankline
surface preparation process. However, like
powder, these materials typically require a
minimum 250 F bake and are limited to detail parts
applications. To date, corrosion performance has
been lower than the current conventional primers
possibly due to lower levels of chromates.
405
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COMMERCIAL AIRPLANE LOW VOC PAfNT DEVELOPMENT
Boeing has worked with aerospace coating suppliers to identify potential
state-of-the-art low VOC coating technologies that can be used to replace the
conventional high VOC coatings. The most critical criterion is that they provide at
least equivalent service performance. Since 1985, over 300 primer and topcoat
formulations have been evaluated (Table I). As a result of close working
relationship between Boeing and coating manufacturers, low VOC coatings have
been added in several Boeing commercial airplane coating specifications as options
to the conventional coatings. Use of these coatings is making significant
contributions to the overall VOC emissions reduction in commercial airplane
manufacturing and maintenance operations.
A. Corrosion Inhibiting Primer For Interior Fuselage Boeing Material Standard (BMS)
10-11, Type I
From the 1970's to the mid 1980's, little progress was made in low VOC
coatings development throughout the commercial airplane industry. By the mid to
late 1980's, a major effort was undertaken by Boeing and aerospace paint
manufacturers as technology advancements were emerging. Also, technology
driving regulations, such as South Coast Air Quality Management District
(SCAQMD) Rule 1124, were being promulgated establishing future dates for lower
VOC primers. All state-of-the-art low VOC primers such as water based, exempt
solvent (1,1,1-TCA) based and high solids technologies from coating
manufacturers were evaluated. By late 1987, only exempt solvent based primers
could meet the regulatory and stringent performance requirements in film
thickness, drying time, adhesion, humidity, hydraulic fluid and corrosion resistance
required by BMS 10-11. Two exempt solvent based primers were added to the
Qualified Products List (QPL) as BMS10-11 Type I, Class A, Grade B primers.
These exempt solvent based primers, while compliant with Rule 1124, contain
large amounts of non-photochemically reactive methyl chloroform. Methyl
chloroform has been identified as an upper atmosphere ozone depletor and its
production will be phased out prior to 1996 in accordance with the Montreal
Protocol. In light of this, the implementation of the exempt solvent based primers
was regarded as an interim solution. Development work, in conjunction with Deft
Chemical Coatings, continued toward development of a hydraulic fluid resistant
version of its Mil-P-85582 water reducible primer. After 5 years of extensive effort
a product was qualified and added to the QPL as BMS 10-11, Type I, Class A,
Grade E.
Table II shows the major property differences between the BMS10-11, Type
I. Grade A (conventional), Grade B (exempt solvent) and Grade E (water reducible)
primers. Figure I shows the rapid viscosity increase of Grade E primer after 4
hours at 75 F. Use of refrigeration to chill the mixed Grade E primer to below room
temperature (above 50 F) has been demonstated to be a viable way of obtaining
longer pot life. Boeing controls allow for only 9 months shelf life as compared to
24 months for Grade A primer demonstrating that these primers are less stable
dispersions than conventional primers.
406
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TABLE I, LOW VOC PRIMERS AND TOPCOATS EVALUATED SINCE 1985
LOW VOC TECHNOLOGY
1/SPEClfJCATlOM
8MS 10-11,
TYPE I
BUS 10-79
TYPES IltMI
BMS 10-11.
TYPE II
•MS 10-60,
TYPE 1
BMS 10-60.
TYPE II
CHROMATE
FREE
•MS 10-66
IMS 10-83
BMS 10-20
JH_
PRIMER
PR 1 NCR
ENAMEL
ENAMEL
ENAMEL
PRIMER
ENAMEL
ENAMEL
PRIMER
KA
SO
7
1
0
0
2
0
0
0
Ml -SOL
33
19
62
5
40
13
5
6
3
WATER
37
12
1
0
0
4
0
2
4
E-COAT
2
0
0
0
0
0
0
0
0
POWDER
0
0
5
0
0
0
0
0
0
TOTAL
122
38
69
5
40
19
5
8
7
DESCRIPTIONS OF SPECIFICATION DESIGNATIONS
BMS10-11, Type I
BMS10-79, Types 11 I III
BMS10-11, Type II
BMS10-60. Type 1
BMS10-60. Type II
BMS10-86
BMS10-83
•MS10-20
Chemical and solvent resistant epoxy primer
Urethant compatible, corrosion resistant pri«er
Cheaical and solvent resistant epoxy enamel
Exterior protective eneael for general use
Exterior protective enamel possessing a high
degree of flexibility for specific use
Teflon filled coating
Interior decorative urethane paint system
Corrosion resistant finish for integral fuel
tanks
407
-------
Time, Hours
FIGURE 1. DEFT 44GN11 VISCOSITY PROFILE at 75F
408
-------
Table II, Differences Between Low VOC and Conventional Primers for Interior
Fuselage Application
BMS1 0-11, Type I
Primer, Grade
% N.V., Admixed
VOC, g/liter
Viscosity, Sees.
No. 2 Zahn
Dry-to-dust,
Mins.
Pot Life, Hours
(At 75 F)
Shelf Life,
Months
A, (Typical)
38.0
Less than
650
15-17
5
16
24
B, (DeSoto)
39.9
Less than
350
(Excluding
1,1,1-TCA)
14-17
15
6
9
B. (Akzo)
32.7
Less than
350
(Excluding
1,1,1-TCA)
15-17
15
16
9
E, (Deft)
35.0
Less than
350
18-22
10
4
9
One of the characteristics of the Deft water reducible primer is that it
requires consecutive additions of three separate and equal quantities of water to
the base/catalyst mix in order to obtain a proper dispersion. The so-called
"waterborne" primers now being developed by other manufacturers include the
water in either the base or catalyst or both and are mixed similar to the
conventional primer. However, further development of this new waterborne primer
technology will be necessary to meet commercial airplane primer specifications.
In addition to these technologies, efforts in high solids primer development
are continuing. Recent submittals from suppliers have shown significant
improvements in application, dry film thickness, dry time and pot life. Electrocoat
primer candidates from PPG and Sherwin-Williams have also been investigated.
Improvement in corrosion resistance and lower bake temperatures are needed to
make electrocoating a viable option for priming commercial airplane components.
B. Corrosion Inhibitive Primer For Exterior Fuselage And Wing Areas (BMS10-79)
In conjunction with the SCAQMD Rule 1124 requirements, an exempt
solvent based primer was added to the QPL of BMS 10-79 as a Type II & III, Grade
B primer in early 1988. Table III compares the major differences between the
Grade A (conventional) and Grade B primers.
409
-------
Table III. Differences Between BMS10-79 Grade A and B Primers
BMS 10-79, Primer,
Grade
% N.V. Admixed
VOC, g/liter
Viscosity, No. 2 Zahn,
Sees.
Shelf Life, Months
Pot Life, Hours
Hydraulic Fluid, 30 days
Immersion at 75F
A, (Type III Typical)
35.7
Less than 650
15-17
12
8
HB I/
B, (DeSoto)
24.2
Less than 350
(Excluding 1.1.1-TCA)
12-16
9
6
4B I/
I/ pencil hardness of coating following exposure
While evaluation of other potential low VOC BMS 10-79 primers (waterborne
and high solids) is continuing, the only low VOC material currently available is the
Grade B primer.
C. Chemical Resistant Epoxy Enamels For Interior Fuselage (BMS10-11, Type II)
Boeing initiated efforts on both interior (BMS10-11, Type II) and exterior
(BMS 10-60) enamels for commercial airplanes since the mid 1988's. Technology
driving regulations were being established. SCAQMD Rule 1124 established a 420
g/l requirement effectivity of July 1, 1991. Since film thickness and dry time
parameter were not as stringent as with primers, the majority of the coatings from
suppliers were high solids enamels which involved less drastic formulation changes
as compared to other technologies. Two qualified low VOC high solids epoxy (less
than 420 g/l) enamels were added to the QPL of BMS10-11 as Type II, Grade D
enamels. These materials have application characteristics similar to the
conventional Grade A coatings, however, they have shorter pot and shelf lives,
longer dry times, and higher application viscosities as shown in Table IV. The
Grade D enamels require only 15 minutes of induction time compared to the 1 hour
required by the conventional Grade A enamels. This is probably due to the use of
lower molecular weight (liquid) epoxy resins in high solids formulations, which
helps to reduce the time for induction.
Several powder coatings were evaluated for qualification as an option to
conventional BMS 10-11, Type II enamels. Appearance (too much orange peel) and
410
-------
the tight tolerance of 250±.5 F in bake were the main constraints in using these
coatings. Efforts to improve appearance and lower the cure temperature by
suppliers are continuing.
D. Exterior Protective Enamels For Wing And Fuselage Areas (BMS10-60, Type II)
High performance urethane enamels have been used as protective topcoats
for the exterior areas of airplanes such as the fuselage and wing areas because of
their superior weather and chemical resistance for many years. As in the case of
interior enamel (BMS10-11, Type II), essentially all the low VOC submittals from
suppliers were high solids (urethane) coatings (Table I). Two high solids urethane
enamels have passed the qualification tests in specification BMS10-60. Table V
shows these qualified enamels perform similarly to conventional solvent based
DeSoto Series 1000 (BMS10-60, Type II, Grade A) . Both DeSoto and Akzo low
VOC products are listed in BMS 10-60 as Type II, Class B, Grade 0 enamels. Time
and temperature cure cycles for these coatings are similar to those for conventional
coatings. Work is continuing with suppliers on improved application properties for
exterior fuselage applications and on lead-, cadmium-, and chrome-free tint lines
for these low VOC enamels as well as a more hydraulic fluid resistant version
(BMS10-60, Type I) of these topcoats for general use.
E. Teflon Filled, Abrasion Resistant Urethane Enamel For Wing Areas (BMS 10-86)
For protection of the high erosion areas of the wings such as the leading
edge and some of the high rub areas (e.g. flap tracks areas of the wings) of the
commercial airplanes, a teflon filled , abrasion resistant urethane enamel (BMS 10-
86) is generally used. Low VOC (less than 420 grams/liter) teflon filled abrasion
resistant urethane coatings from Crown Metro have been qualified to BMS 10-86
as Type I (sprayable) and Type II (brushable) Grade 0 enamels. These high solids
urethane enamels have improved (significantly shorter) drying times compared to
conventional Grade A coatings. With the high solids enamel, usually two coats will
be sufficient to provide 5 to 10 mils film thickness required by BMS 10-86
whereas, with the conventional Grade A enamel, 3 to 4 coats are required.
F. Additional Low VOC Paint Development Efforts For Commercial Airplanes
During the past several years, Boeing has also been evaluating both
waterborne and high solids candidates for a variety of other coating types as
shown below:
o Corrosion resistant finish for integral fuel tank (BMS 10-20)
o Interior decorative urethane paint system (BMS10-83)
o Nonchromate primer for nonmetallic composites (BMS10-103)
o Flexible corrosion inhibiting coatings for in-spar areas of the wings (BMS10-100)
o Nonchromate primer for metals
411
-------
Table IV, Differences between BMS10-11, Type II, Grade A and 0 Enamels
BMS1O-11, Type
It, Class B, Grade
%N.V.. Admixed
VOC, g/liter
Viscosity, Sees.
Zahn No. 2
Pot Life, Hours
Shelf Life,
Months
Induction Time,
Hours
Dry Time, Hours,
At 75 F
Dust Free
Tack Tree
Dry Through
Dry-to-stack
Appearance
Sag
A, (Typical)
49.6
Less than 600
20-25
16
24
1
1/2
3
6
8
Control
None
D, (Akzo 446-22
Series)
67.7
Less than 420
25
4
9
1/4
2
4
9
9
Slight Orange
Peel
None
D, (Crown Metro
14P21 Series)
61.8
Less than 420
28
4
9
1/4
2
4
6
7
Slight Orange
Peel
Slight
412
-------
Table V, High solids exterior protective urethane enamels
BMS 10-60,
Type II, Class
B, Grade
%N.V.,
Admixed
VOC, g/liter
Viscosity,
sees., Zahn
No. 2
Shelf Life,
Months
A, (DeSoto
.-Series 1000
Control)
54.8
534
16-18
12
D, (DeSoto
Series 420)
65.95
417
17-19
9
D, (Akzo
646-88
Series)
64.71
418
20-24
9
Table VI, Dry time and shelf life for BMS 10-86 Grade D enamels
BMS10-86. Grade
%N.V., Admixed
VOC, g/liter
Dust Free, Hours
Tack Free, Hours
Dry Through, Hours
Shelf Life, Months
A, (Typical)
55.6
500-590
Type 1 2.0
Type II 2.0
Type 1 6.0
Type II 4.0
Type 1 12.0
Type II 6.0
12
D, (Crown Metro 23T3
&24T3 Series)
68.0
Less than 420
Type I 1.5
Type II 0.75
Type I 3.25
Type II 2.0
Type I 5.25
Type II 3.1
9
413
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Several low VOC technologies for BMS10-20, BMS10-83 and BMS10-103
are currently being evaluated. For flexible corrosion inhibiting coatings for in-spar
wing areas (BMS 10-100), high solids vinyl technology may be available from
suppliers in the near future. However, the availability of a low VOC nonchromate
primer for use on aluminum structures will at best, several years away. Current
state-of-the-art nonchromate corrosion inhibitive pigments do not perform as well
as chromate pigments in protecting adjacent scratched or damaged (uncoated)
areas. Corrosion pit depths of 1 to 10 mils have been observed in scribed areas on
2024-T3 bare aluminum panels coated with primers containing nonchromate
inhibitors after 3000 hours salt spray exposure3. This is quite large when
compared to attack observed with conventional chromated primers, which ranges
from 0 to 0.1 mils depth. Boeing is also evaluating potential corrosion inhibitors
using electrochemical polarographic and impedance techniques. If a suitable
inhibitor is identified, cooperative efforts with coating suppliers to develop an
acceptable primer will follow.
CONCLUSION
Significant progress has been made by the joint efforts of the Boeing
Company and its coating suppliers in development of low VOC primers and
enamels for commercial airplane paint operations. Since 1985, over 300 different
state-of-the-art low VOC primer and enamel formulations have been tested. As a
result of this effort, several low VOC coatings have been developed and qualified.
This is allowing Boeing and its subcontractors to significantly reduce VOC.
emissions from painting operations. Based on EPA paint usage and emissions
estimates for commercial aerospace painting operations, it is estimated that use of
the materials developed to date will provide approximately a 40% reduction in
paint emissions by Boeing and its subcontractors.
414
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REFERENCES
1. Rules and Regulations, South Coast Air Quality Management District, Rule
1124 - Aerospace Assembly and Component Coating Operations, Amended
April 3, 1987, 9150 Flair Drive, El Monte, Calif. 91731.
2. Alters, R. A., U.S. Patent 4,352,898, "Water-Reducible Epoxy Coating
Compositions Without Emulsifier", October 5, 1982.
3. "Salt Spray (fog) Testing", Boeing Specification Support Standard 6SS
7249, Aug. 22, 1988.
415
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416
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SESSION 10
AUXILIARY SYSTEMS
PAPERS PRESENTED:
"Low Volatility Surface Preparation: A Hybrid Approach"
by
Joseph A. Lucas
Inland Technology, Inc.
Tacoraa, Washington
'Transfer Efficiency and VOC Emissions of
Spray Gun and Coating Technologies in Wood Finishing"
by
Lesley Snowden-Swan
Pacific Northwest Laboratory
Richland, Washington
and
Pamela Worner
Pacific Northwest Pollution Prevention Research Center
Seattle, Washington
"You Can't Always Judge a Paint Spray Gun Cleaning System by Its Cover"
by
Michael J. Callahan
Project Engineer
John P. Kusz
Manager of Product Development
Safety-Kleen Corporation
Elgin, Illinois
417
-------
(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
LOW VOLATILITY SURFACE PREPARATION:
A HYBRID APPROACH
Joseph A. Lucas
Inland Technology Incorporated
2612 Pacific Highway East
Suite C
Tacoma, WA 98424
©1993
(Reproduced with Permission)
419
-------
In the past, industrial surface preparation practices have generally involved some variant
of the following solvent usages:
1. Manual wiping with MEK, MffiK, Lacquer Thinner, Acetone, 1,1,1 Trichloroethane,
Freon 113, Methylene Chloride, Xylene, Toluene, or Mineral Spirits.
2. Agitated dips or sprays using many of the above compounds.
3. Vapor degreasing using Freon 113, 1,1,1 Trichloroethane, Trichloroethylene or
Perchloroethylene.
These materials and methods have worked well for industry as surface preparation
techniques, primarily because they have grown up with industry during the last 50 or so years. As
a new industrial cleaning need was identified, a selection of these solvents was empirically tested
by the users; and, when one was determined to work effectively, it was adopted into the process.
In fact these traditional solvents were so effective, in terms of cleaning efficiency and
economy, they were nearly "no brainer solvents". In other words one could literally specify
"vapor degrease with 1,1,1 Trichloroethane" without knowing how clean that makes a surface,
knowing how effective it was at removing specific contaminants, or knowing anything about the
follow-on requirements, and still be fairly certain everything would work. They could be certain
that the weld would perform, the paint would adhere, and the adhesives would bond.
Now, with the effects of The Clean Air Act, the Montreal Protocol phase out, the V.O.C.
labeling requirements, and VOC limitations from a variety of sources looming imminent, these
traditional industrial solvents are under major attack; and their continued use in industrial
processes are becoming a major disadvantage for all industrial users.
This has, in the last two years, created a major push to discover and develop alternative
chemistries, and alternative processes, to accomplish the same surface preparation tasks without
incurring the same regulatory pressure and without causing the same risks to the environment and
human health.
Contrary to the "No Brainer" characteristics of the traditional surface preparation techniques,
alternate chemistries and processes are by no means as universally effective. In fact they tend to
be extremely application specific. For example, a major aircraft manufacturer used MEK to prep
prior to painting, sealing, bonding, and welding. It also used MEK to remove adhesive, remove
cured sealant, remove DyChem layout dye to remove part marks, and for cleaning painting
equipment. The low VOC surface preparation that was developed to prep prior to painting,
bonding, sealing or welding works well for those applications but will not remove DyChem dye
part marks, cured sealant or protective wing coatings. A different substitute was developed that
removes DyChem dye, cleans paint equipment, and removes some adhesives, however it will not
prep surfaces, remove cured sealant, or remove protective wing coatings. A third substitute that
will remove cured sealant and adhesives will not prep surfaces or remove protective wing
coatings. Protective wing coatings must be removed by means of yet a fourth material.
420
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To add to this complexity there is very little existing information or data regarding the
cleanliness requirements for any of the typical industrial follow-on processes. This naturally
means that there is no way to effectively compare cleanliness results achieved via a potential
substitute against a known requirement. This lack of data within industry continually raises the
specter of the unknown. Will the weld hold as good, will the paint bond as well, will the circuit
board last 20 years, or will some unobserved or unknown difference in the process put the
company's product and reputation in jeopardy? This lack of good, replicable, comparable test
data is probably the primary impediment to the efficient design and adoption of low VOC
chemistries and processes, a more complete list of impediments is as follows:
1. Research chic
2. Research and design first, find application second
3. Desire for quick fix that behaves like the old stuff
A. We tried that before and it didn't work
5. No involvement of line workers
6. Unwilling to look at process changes and equipment changes
7. Fear of unknown effects of new materials
8. Lack of management courage
9. Lack of real data about processes. Is this chemical really necessary?
10. Failure to look upstream for changes that may make a chemical unnecessary
11. Unwilling to make employees accept the need to change
12. Desire for substitution of a product and/or process that is already validated, reluctance to
do on site testing and adaptation.
13. Establishing substitution criteria that pre-ordains failure. The substitute must:
A. Be non-flammable
B. Be non-toxic
C. Be non-regulated
D. Work with minimal process changes
E. Be cheap/
421
-------
14. Lack of real technical knowledge about the current process
IS. Lack of real technical data about the proposed alternative chemical/process. How clean
does this get and is that good enough?
Some of these impediments can be ameliorated by shifting the attention away from the
seductive tendency to focus on the solvent that is to be eliminated. Currently the cry is "I want a
replacement for 1,1,1 Trichloroethane". This focus is usually of limited productivity because of
the lack of process information. Was 1,1,1 Trichloroethane being used because it alone would
remove the particular contaminants sufficiently for the follow-on process or was it being used
because it worked? Was its use in essence the result of industrial habit?
The most productive focus in designing or trying to identify a substitute is to focus on the
application for which the current solvent is being used. What must be accomplished in order for
the follow-on process to work?
The following is a helpful diagnostic protocol that is designed to aid in deriving the necessary
data from the industrial solvent usage process:
1. What is the solvent being substituted? Why is this particular solvent being used for this
process?
2. What is the motivation for this substitution?
3. What is the process the solvent is being used in? Manual wipe, vapor degreaser, ultra
sound, etc.
4. What is the substrate?
5. What are the contaminants that are being removed? What is their origin?
6. What are the follow-on processes? Do they require this cleaning step?
7. How clean do you need the surface to be for the follow-on process?
8. Are there any centra-indications? (i.e. sulfur with aluminum at high temperatures)
9. Have you tried anything else as a substitute? What was it? What were the reasons for its
non-acceptance?
Over the course of the last several years, we at Inland Technology have not only been
developing data on the performance of our products, but we have been collecting quality data on
the cleaning performance of many of the traditional solvents. Researchers have used a wide
variety of test methodologies and measuring equipment. Much of the test results are not
comparable in any meaningful way between methods, however this information, sketchy though it
may be, should be the beginning of a useful base line of performance data that will enable
industry, by using identical test methodologies, to begin comparing the performance of substitute
chemistries and processes.
-------
The following is test data comparing the performance of traditional solvents with Inland
Technology alternatives:
OSEE TEST
Traditional Solvent 1,1,1 Trichloroethane
Inland Technology Alternative Citra Safe®
Delta cV -135
Delta cV -32.2
On OSEE tests the smaller the Delta cV either positive or negative the cleaner the surface.
NVR TEST
Traditional Solvent 1,1,1 Trichloroethane
Inland Technology Alternative Citra Safe®
MG/Plate8"xl2" 1.0-1.47
1.73
X-RAY FLUORESCENCE
Traditional Solvent Isopropyl Alcohol
Traditional Solvent Freon TE
Inland Technology Alternative Citra Safe®
Inland Technology Alternative Skysol 500
Control Uncleaned Aluminum
4 Counts/Second
ND (non detectable)
2 Counts/Second
ND (non detectable)
301 Counts/Second
OPTICAL SCANNING TEST
Traditional Solvent Freon T.E.
Inland Technology Alternatives
Outperforming Freon T.E.
EP921
X-CALffiER
CITRA SAFE®
Expanding on this small beginning by developing on this base of test data should help take the
development and adoption of alternative surface preparation chemistries and processes out of the
frustrating, risky, labor intensive realm it currently occupies, and through the development and
use of scientific performance data, put this process firmly into the less stressful engineering realm
where it belongs.
To date most of the chemical design work in the low VOC substitute arena has focused on
the following aqueous, semi-aqueous, and hydrocarbon cleaning chemistries. These approaches
have several inherent disadvantages that have impeded their universal adoption.
DISADVANTAGES OF AQUEOUS CLEANING
1. Typically does not lend itself to manual surface cleaning
2. Parts with blind holes and small crevices may be difficult to clean and require expensive
process optimization
423
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3. Less effective on non-polar soils than polar
4. Potential for galvanic corrosion to occur during process
5. Some materials and processes are incompatible with water
6. Higher energy consumption
7. Rinsing difficulties-Some surfactants and other components can be difficult to rinse
8. Sometimes high concentrations of organic coupling compounds contribute to organic
emissions.
9. Process equipment tends to be large and requires considerable space.
DISADVANTAGES OF SEMI-AQUEOUS CLEANING
1. Typically does not lend itself to manual surface cleaning
2. Flammability - especially if sprayed
3. Odors
4. High hydrocarbon content (terpenes etc.) can auto-oxidize in the presence of heat, water,
and air to increase non-volatile residue problems
5. Sometimes the surfactants are difficult to rinse
6. The chemistry of maintaining proper emulsion characteristics during the process can be
difficult
7. Higher organic concentrations can lead to higher organic emissions.
DISADVANTAGES OF STRAIGHT HYDROCARBON CLEANING
1. Flammability Problems
2. Typically 100% VOC
3. The need for low non-volatile residue tends to require the use of lower flash point lighter
fractions that evaporate rapidly and contribute massively to organic emissions
4. Low-volatility hydrocarbons typically leave objectionable residue unless extremely purified
to include only one hydrocarbon chain
5. Typically not effective on all soils
424
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6. Contaminate build-up in the cleaning tank can quickly cause a failure of the follow-on
process
HYBRID CHEMISTRIES
As a result of the difficulty experienced in attempting to replace the Ozone depleting
substances and other traditional highly volatile solvents, with more benign chemistries following
the approaches of aqueous, semi- aqueous, and hydrocarbon technologies, Inland Technology
Incorporated has developed a new hybrid approach, that from preliminary test data, promises to
solve many of the inherent problems associated with the other three approaches (Aqueous, Semi-
Aqueous and Hydrocarbon cleaning systems). This for lack of a better term is being referred to as
"Hybrid Chemistry".
In many respects this Hybrid Chemistry incorporates many of the advantages of Aqueous,
Semi-Aqueous and Hydrocarbon cleaning systems while eliminating or markedly reducing many
of their inherent disadvantages.
These modified hydrocarbon systems provide aggressive removal of a wide range of
contaminants. Components with large differences in inter-molecular forces of non-polar
dispersion, polarity, and hydrogen bonding are combined together to optimize contaminant
solubility. On the molecular level this means that components with the greatest affinity to the
contaminant tend to dominate the surface interface between the liquid and the contaminant; that
component is also most likely to solubilize the contaminant. As a result, one blend might provide
the characteristics necessary to remove several very different contaminants. Hydrophobic
contaminants are attracted by the high dispersion, low polarity, and low hydrogen bonding
components of the system. Various "modified" hydrocarbons - oxygenated, nitrogenated, but not
halogenated - are used to attack polar, and hydrogen bound contaminants. Coupling agents are
present to facilitate rinsing and solubilizing of all the materials including the contaminant.
ADVANTAGES OF HYBRID CHEMISTRIES
• Can be designed to be nearly or essentially non-volatile.
Even though they may be non-volatile, hybrids can be designed to be extremely free
rinsing.
Hybrids can have extremely high flash points.
Hybrids can contain design components that exhibit strong polarity, strong dispersion
forces and strong hydrogen bonding characteristics to enable one cleaning agent to be
effective on a wide variety of contaminants.
Hybrids exhibit a high capacity for contaminant loading while maintaining specified
cleaning requirements.
Hybrid chemistry is capable of delivering the exquisitely clean surfaces mandated by the
most demanding of precision cleaning requirements.
425
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Several such hybrid systems have been designed by Inland. Most of the components of our
hybrid systems originated from usage in industries such as the food industry and cosmetics
industry. All have relatively high flash points, extremely low vapor pressures, and provide a major
improvement in human and environmental safety. Three of the products are CITREX, X-
CALIBER,andEP921.
X-CALIBER
This product is designed to replace TCA, TCE and Methylene Chloride as a surface prep and
stripper. It is used as an in-tank solution substitute for vapor degreasing with TCA, TCE or
Freon. It is also used for paint and coating stripping as a substitute for Methylene Chloride. X-
CALIBER has the ability to aggressively remove and suspend both polar and non-polar
contaminants.
Highly polar at the same time with strong London forces of dispersion, X-CALIBER attacks
a wide variety of contaminants. Its hybrid nature tends to keep contaminants mobilized thereby
reducing the effects of contaminant build-up in the tank. This characteristic is a major technical
improvement over most straight hydrocarbon or aqueous/semi-aqueous cleaning chemistries.
CITREX
CITREX has many of the same characteristics as X-Caliber, but it is less aggressive and has a
lower surface tension. It is another in-tank substitute for vapor degreasing and also stripping
procedures. It is slightly less aggressive than X-Caliber, but it does have a higher flash point (142
°F), CITREX wets most surfaces better than X-Caliber and is more easily rinsed with water.
EP921
EP-921 is a design effort to tame the hybrids sufficiently to allow for their use as hand
applied wipes for surface preparation prior to painting and other follow-on processes. Like all of
the hybrids, a follow-up rinse or wipe is required as a standard process to achieve the low N. V.
R., of which they are capable. In the case of EP-921, a simple rewiping of the surface with a rag
dampened with water has proven sufficient for most follow-on processes.
While X-CALIBER and CITREX more nearly substitute for TCA & TCE, EP-921 was
designed chemically to more nearly mimic the behaviors and characteristics of Methyl Ethyl
Ketone.
This led to the discovery of a new application for this extremely low volatility solvent
substitute. Although 25 - 30% of solvent emissions in coating related activities come from
surface preparation, another, nearly equal, 25% is related to paint equipment clean up.
EP-921 is a low volatility substitute for MEK and is effective at thinning and mobilizing
most of the paints and coatings it has been tested against. Guns, pots, etc. clean up with the same
effort, the same equipment, and the same techniques as with using MEK.
426
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The major advantages are: a vapor pressure of <. 1 M M H G instead of 75 M M H G.
This makes EP-921 750 times less volatile than M.E.K.
EP-921 has a flash point of 146 °F - rather than the 20 °F flash point of M.E.K. and has a
much more benign toxicology for worker safety.
427
-------
12-T-
104-
A Hybrid Cleaning System's (X-CALIBER)
Effectiveness Compared to the Cleaning
Effectiveness of 1,1,1 Trichloroethane (TCA)
Non Volatile Residue Measured by EUipsometry
to
00
S 8
I TCA
I X-CALIBER
10
20 30 40
Time (days)
Plot of Elipsonteter Data For Solvents Tested
-------
SOLVENT SUBSTITUTION
CASE STUDY
CLIENT:
The Boeing Company
PROJECT:
Eliminate or severely reduce the use of the Methyl Ethyl Ketone used for
cleaning paint guns & painting equipment used in aerospace coating
applications. A successful substitute must be less hazardous than MEK and
must fit within the VOC regulations promulgated by PSAPCA and
SCAQMD.
CONCERNS:
The project raised three major areas of concern:
1. VOC regulations demand near non-volatility in paint gun cleaning materials.
This lack of volatility raised possible contamination issues with regards to
painting subsequent to cleaning with substitutes.
2. Most paint equipment is designed to be resistant to MEK. There will be very
little data available regarding component resistance to any substitutes.
3. There are a great variety of coating systems in use today. The goal of the
project was to create a substitute with the near universal applicability of
MEK.
SUBSTITUTION PROCESS:
1. Try to create on a macro scale a material that mimics some of the electro
chemical characteristics of MEK.
429
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2. Keep the vapor pressure below .5 mmHg & the volatile content below 200
grams per liter.
3. Test candidates on as many paint & coating systems as possible.
4. Devise & test purging techniques to eliminate paint contamination questions.
METHODOLOGY:
The final candidate was a cleaning formulation identified as EP921. This
material was constructed from mutually antagonistic materials that as a
whole mimic, on a macro scale, the solubility parameters & the solubility
vector enjoyed by Methyl Ethyl Ketone.
Its near non-volatility would allow it to compete effectively, in terms of
emissions, with MEK coupled with a vapor capture system of 99.7%
efficiency.
Cleaning effectiveness equal to MEK on 1011 Epoxy Primer, 1060 Series
Topcoat, iron, alkyd enamels, varnish, polyeurothanes, & silicone coatings.
Residue concerns have been eliminated by the successful use of a warm
water final rinse of the paint gun. This is then followed by an air blast to
dry the gun prior to use.
Testing on paint gun components to date has not resulted in identifying any
material adverse effects.
RESULTS:
The client is continuing testing & initiating Boeing Material Technology
materials testing prior to developing specifications for use. Northrop
Aviation has also conducted tests & has received preliminary approval from
SCAQMD and PSAPCA. Evaluation regarding Aerospace VOC regulations
430
-------
is in process. The original client is experimenting with other applications
for this mimic of MEK.
To date, good preliminary results have been obtained in the following
traditional MEK applications:
• Felt marker remover
• Removal of glues & adhesives
• Mild paint remover
• Grease & oil remover
• Machinists blue dye removal
431
-------
«<
!w • *ji5*n«<**t- ^Tf«s»s^&fcv» v*** I*.:-- j; *f*
InlaDdfTechnpl^pIncorporateJ
Inland Technology Incorporated, is * privately owned corporation that is dedicated
to the development and production of advanced solvents that are critical to all
industries having to respond to the environmental challenges of the 1990s. Inland,
operating from their facilities in Tacoma, Washington, is committed to customer
satisfaction through quality - Total Quality Management (TQM) is an essential
component of Inland's corporate commitments. During the past eight years, Inland
has become a preeminent company in the advancement of environmentally
responsive solvents:
• Inland is a member of the Joint Association for the Advancement of
Supercritical Technology (JAAST). Inland was invited to participate as a full
member amongst other technology giants such as Los Alamos National
Laboratories, Battelle Northwest Laboratories, IBM, Boeing, Hughes and
Autoclave Engineering.
• Inland is an invited member of International Air Transport Association and
participated in their subcommittee for non chlorinated paint stripping
alternatives.
• Inland is active in the ASTM G-4 subcommittee searching for new technologies
for cleaning LOX lines.
• Inland is active in the SAEG-9 subcommittee on advanced methods for sealant
applications
• Inland is an invited participant on U.S. Environmental Protection Agency's "Use
Cluster" committees for development of printing and aerospace industry
regulations.
Inland actively supports many of the largest companies in the United States, as well
as federal government agencies, including: Westinghouse, Weyerhaeuser, Kodak,
McDonnell Douglas, Grumman, Northrop, Boeing, Los Alamos National
Laboratories, Lawrence Livermore National Laboratory, U.S. Navy, and the U.S.
Air Force.
432
-------
TO DATE, THE SCIENTISTS AND ENGINEERS AT INLAND TECHNOLOGY INC.
HAVE DEVELOPED SUCCESSFUL SUBSTITUTES FOR THE FOLLOWING PROBLEM SOLVENTS:
•Hi
fei^i^
Methylene
Chloride
1,M
Trichloroethane
Methyl Ethyl
Ketone (MEK)
Toluene / Xylene
Acetone
Stoddard Solvent /
Mineral Spirits
Trichloroethylene
Perchloroethylene
Methyl Ethyl
Ketone (MEK)
Freon 113
1,1,1
Trichloroethane
tiiiMHttsliBHlSnHalHn fflBIBBjP
lilt
Paint stripping; cold
tank soak; resin
removal
Electronic & electrical
cleaning. Also, metal
preparation
Surface preparation for
painting or welding
Surface preparation for
painting or welding
Cleaning of fiberglass
&. epoxy resins
Parts washing &. paint
cleanup
Degreasing & resin
removal
Degreasing
Paint Gun Cleanup
Vapor Degreasing;
Precision Cleaning
Vapor Degreasing;
Precision Cleaning
CITREX
X-CALffiER
CITRA SAFE®
TEKSOL EP
SAFETY PREP
CITRA SAFE
TEKSOL EP
SAFETY PREP
CITRA SAFE
TEKSOL EP
Z-STRJQ?
CITREX
CITRA SAFE
TEKSOL EP
BREAKTHROUGH
CITREX
TEKSOL EP
CITRA SAFE
CITRA SAFE
ISO-PREP
BREAKTHROUGH
EP921
CITRA SAFE OR
SKYSOL
WITH ULTRA
FILTRATION
CITRA SAFE OR
SKYSOL
WITH ULTRA
FILTRATION
Both products are biodegradable. CITREX is
not regulated by RCRA or SARA, Title III.
Both are low VOC.
CITRA SAFE is biodegradable; TEKSOL EP is
not regulated by SARA, Title III. Both are low
VOC and non chlorinated
SAFETY PREP. CITRA SAFE and TEKSOL
EP are biodegradable; all arelowVOCs
Same as above
Low VOCs & toxicity; High flash point;
CITREX is biodegradable
Low VOCs; CITRA SAFE is biodegradable.
BREAKTHROUGH is free from most
regulations TEKSOL EP is low toxicity
CITREX and CITRA SAFE are biodegradable,
low VOC. TEKSOL EP is non chlorinated with
low toxicity
Non-halogenated
Low VOCs, easier disposal; Low Toxicity
Biodegradable, High Flash Point, Low VOC.
not regulated by RCRA or SARA Title IB
CITRA SAFE biodegradable; SKYSOL is not
regulated by RCRA or SARA Title ID, Section
3 13. both are low VOCs
CITRA SAFE is biodegradable; SKYSOL is not
regulated by RCRA or SARA Title ITJ, Section
3 13, Both are low VOCs
It should be noted that performance needs vary from application to application and that none of these substitutes
should be expected to be 100% cross over for all applications.
Also, the chemical behaviors of these substitutes (vapor pressures, dry time, etc.) may differ from solvents being
replaced which may require changes in work practices in order for substitutes to be successful
Inland Technology, Inc.
1990 (Reproduced with Permission)
433
-------
434
-------
(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
TRANSFER EFFICIENCY AND VOC EMISSIONS
OF SPRAY GUN AND COATING TECHNOLOGIES
IN WOOD FINISHING
Lesley Snowden-Swan
Pacific Northwest Laboratory
Battelle Boulevard, P8-48
Richland,WA 99352
Pamela Womer
Pacific Northwest Pollution Prevention Research Center
1326 Fifth, Suite 650
Seattle, WA 98101
SUMMARY
This study was designed to determine which factors most strongly influence net volatile
organic compound (VOC) emissions and transfer efficiency (TE) of a spray coating operation in
a "real-life" wood finishing environment. Factors tested included spray equipment types and
coating types, as well as painter skill level and target size and shape. Transfer efficiency and
coating usage were measured to rate the overall system performance (coating type plus
application method) in an operating wood finishing shop. The equipment was designed to be
representative of small- to medium-sized businesses in the wood finishing industry.
The study was not designed to determine the maximum achievable transfer efficiency for
the various spray guns, but rather to provide a non-biased test of "off-the-shelf" equipment not
optimized with variable tips. Spray time was included in the data in order to aid in the analysis
of possible effects of the variables on production rate. The study showed that a painting
operation must be viewed as a system, with gun type, coating composition, and especially
painter skill all affecting environmental performance. The results also indicated that
water-borne coatings may hold significant long-term potential for VOC reductions in wood
finishing, and that painter skill level also exerts a strong influence on both transfer efficiency
and VOC emissions.
INTRODUCTION
Improving transfer efficiency (TE) in spray coating operations would reduce
coating waste and VOC emissions, cut hazardous waste disposal fees and coating costs, and
lessen worker exposure to potentially hazardous materials. Changing from 30 percent
transfer-efficient equipment to 65 percent transfer-efficient equipment would reduce materials
usage by approximately 50 percent1. Many factors affect achievable TE, including spray
equipment type, size and geometry of the target, coating type, skill level of the spray operator,
air velocity, atomizing air pressure, fluid flow rate, and fan size.
435
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In this study, the impact of several factors which can affect achievable TE were
investigated, including spray equipment type, size and geometry of the target, solids content of
the coating, and skill level of the operator. Transfer efficiency and VOC emissions were
calculated for each of these factors. Other factors which may affect TE, such as air velocity,
atomizing air pressure, and fluid flow were monitored and kept as stable as possible for the
duration of the spraying procedures. Environmental impact is clearly shown by the data on net
VOC emissions, expressed in pounds of VOC per pound of solid applied, since those figures
reflect both transfer efficiency and VOC content of the coating.
METHODOLOGY
Testing Environment
Spraying was conducted inside a concrete dry filter spray booth of dimensions 14* x 43
x 94' at a wood finishing facility in the Puget Sound area. Fresh dry filters were installed in
the booth prior to testing. The average temperature, percent humidity and air velocity in the
booth for the duration of testing were 70F, 65 percent, and 180 ft/rain, respectively.
Operator Skill Level
To determine the importance of the human application factor on spray efficiency, the
tests were performed with both a very experienced painter (over ten years spray painting
experience) and a painter with limited experience (less than one year). The experienced sprayer
had substantial experience with all of the spray guns tested. The novice sprayer had used all of
the guns at least once; however, the bulk of his experience was with the HVLP air-assisted and
HVLP equipment.
Target Size and Geometry
To investigate the effects of target configuration on transfer efficiency, two types of
targets (door panels and cabinet face frames) were sprayed for each set of equipment and
coating type used. The door panels provided a large flat target surface, while the frames
offered a more complex shape. The door panels used were standard sized mahogany doors
(dimensions 28" x 80", with a thickness of 1 3/8"). The simulated cabinet face frames were
approximately 18" by 30", constructed from 2 1/4" x 1/2" hemlock door casings.
Coating Type
The physical properties of each coating type are listed in Appendix A, Table A. 1. Each
coating type consisted of a stain, a sealer, and a topcoat. A single brand of stain was used for
all tests. Stain usage was measured for the initial tests. However, because the weight of stain
used was negligible compared to the weight of the sealer and topcoat, stain usage was found to
have no measurable effect on the calculated TE of the total coating system. Therefore,
although stain was applied in the remainder of the tests, stain usage was not included in the
transfer efficiency determination.
The 25 percent solids and 30 percent solids alkyd modified nitrocellulose lacquer are
solvent-based coatings which are cured through the normal evaporative process to remove the
436
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solvent. This type of coating is generally not available in a low-VOC material2. Spraying was
also conducted with the 30 percent solids sealer combined with a 40 percent solids aikyd/urea
conversion varnish for the topcoat. This latter material contains a catalyst which promotes
curing through a polymer crosslinking process. Though this type of coating is generally
available in high solids (low VOC) content, the shelf life of the final mixed material (catalyst
plus varnish) is less than one day, and thus good planning and management is required to avoid
wasting material.
The third type of coating investigated is a self-seal acrylic emulsion water-borne lacquer
(32 percent solids). While the use of water-borne coatings substantially reduces VOC
emissions, these coatings generally require longer drying times compared to solvent-reducible
materials, and generally require a heated environment, such as a curing oven. Despite these
difficulties, water-borne coatings can be applicable to the wood finishing industry with some
procedural modifications.
Spray Equipment Type
The spraying procedure used was modeled after regular production procedures used in
the shop. Complete equipment specifications for the technologies chosen for testing is provided
in Appendix A, Table A-2. The equipment tested was selected by spray gun and coating
manufacturers' representatives participating in the study and are considered to be representative
of technology available to small- to mid-sized wood finishing businesses.
The actual guns used in the study were newly purchased. In addition, the guns were
used with the tips which were packaged with them, and no attempt to optimize gun performance
by using variable tips was made. The guns were intentionally used in this manner to provide a
flat comparison of "off-the-shelf1 equipment.
Volume and Mass Measurement
Several measurements were necessary for the calculation of TE (see Appendix B,
Equation B-l), including volume of coating used, mass of solids deposited on the target, weight
percent solids, and density of the coating. The latter two measurements were also necessary for
calculation of VOC content (see Appendix B, Equation B-4). The volume of coating material
sprayed was measured using a fluid flow meter in conjunction with a pro-pulse receiver
module. The mass of solids deposited on each target was determined by weighing the target
before and after the coating system was applied using a Toledo SM30000 precision platform
scale (+/-0.1 gram).
Physical Properties Measurement
Coating samples were taken at the time of spraying and stored in sealed cans for later
analysis in the laboratory. Percent solids, density, and viscosity were measured in a coatings
laboratory. Weight percent solids was determined by weighing a designated quantity of coating
specimen into an aluminum foil dish and heating at 200 degrees F to constant weight
(approximately two hours). Density and viscosity measurements were made at the coating
temperatures used for spraying using a weight-per-gallon cup and a Zahn #2 cup, respectively.
437
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RESULTS
Transfer Efficiency
The transfer efficiency results vary widely. The maximum TE achieved in any of the
tests approached 70 percent for the experienced sprayer and 60 percent for the novice sprayer,
achieved both in spraying doors with the HVLP air-assisted gun and 30 percent solids coating
system, and in spraying doors with the HVLP gun and water-borne system configurations (see
Figure 1). The minimum TE achieved was 23 percent for the experienced sprayer when
spraying frames with the conventional gun and 30 percent solids system, and 18 percent for the
novice spraying frames with the HVLP-1 gun and 25% solids system. Due to the number of
tests performed, it is difficult to determine immediately from these results the influence of
individual factors such as gun type or coating on TE. It is most useful to consider each factor
separately, as follows.
There is much concern and controversy within industry and the regulatory community
regarding which spray gun technology gives the highest transfer efficiency. The EPA assumes
a TE of 25 percent for conventional airspray, 40 percent for air-assisted airless, and 40 percent
for airless spray (for the coating of metal parts). Although there is no universal TE assigned to
HVLP, EPA region IX (San Francisco) assumes TE for HVLP to be greater than 65 percent
(equivalent to electrostatic spray). Results from this study do not indicate a direct correlation
between TE and spray gun type. Although individual guns did vary in TE, no one gun
consistently outperformed another with all of the coatings used. In addition, the TE achieved
by one gun varied by as much as 50 percent depending on the specific test configuration.
Again, it should be noted that the spray equipment was not set up to give the optimum TE (i.e.,
with variable fluid tips and air caps), but rather were used off-the-shelf as received from the
manufacturer. Pressures of fluid and air were, however, adjusted at the start of each test to
ensure the best performance possible with the existing equipment.
Although transfer efficiency does appear to be affected by coating type, there is no clear
trend regarding the relationship between percent solids and TE. Perhaps the most consistent
factor seen to exert an influence on transfer efficiency is painter skill level. In 90 percent of
the combinations tested, the expert sprayer achieved higher transfer efficiency than the novice.
In fact, the differences in transfer efficiency due to painter skill level with a single gun type
were often larger than differences between gun types. It is evident from these results that
painter training and experience is a crucial factor in achieving optimal TE performance for
spray coating operations.
Volatile Organic Compound (VOC) Emissions
A useful parameter for incorporating both the TE and VOC content of a coating
application system is emissions (E). Emissions were calculated in this study as Ib VOC/lb
solids applied to the target (see Appendix B, Equation B.4). It is important to first notice the
inverse relationship between TE and VOC emissions, i.e., with an increase in TE comes a
decrease in VOC emissions. For example, spraying frames results in higher VOC emissions
and lower TE, and the experienced sprayer consistently achieved lower emissions and higher
TE than the novice.
438
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The most significant influence on emissions, however, appears to be the actual VOC
content of the coating material. Emissions appear to consistently decrease from the lower solids
solvent-borne material to the higher solids material. In addition, tests run with water-borne
coating show significantly lower emissions than all of the solvent-borne coatings.
Measurements of the amount of material of each coating type used to perform the spray
operation were also taken. The results of these measurements demonstrate that, for each
equipment configuration, the amount of water-borne coating material used was consistently
lower than the solvent-based coating types. Obviously, reducing the amount of material used
reduces the environmental impact of that material.
Spray Time
Although TE and VOC releases are perhaps the most important factors determining
environmental performance of a spray painting system, an equally important consideration from
an economics standpoint is production rate. If, for example, a particular spray gun technology
offers high TE but decreases production, material cost benefits due to increased TE may suffer.
In order to provide insight into the possible effects of gun type on production rate, spray
times were measured for each combination of spray gun and coating system. The average
results of these times are shown in Figure 3. With regard to gun performance, airless
application proved to be the quickest application method, while HVLP was the most time
consuming. Once again, differences between the experienced and novice spray times clearly
show the advantages of using a trained painter.
CONCLUSIONS
Strong conclusions regarding the effects of gun type on transfer efficiency or VOC
emissions are difficult to draw from the data. However, a few important points regarding
environmental effects in wood finishing operations are clear:
Painter skill level has a strong influence on achievable TE, VOC emissions, and spray
time. This element of the system is a direct and simple measure for improving environmental
performance. Training, both introductory and on-going, should include spray techniques,
coating content, equipment set-up, and optimization.
Several factors work as a system to affect environmental performance. These include
painter skill level, spray equipment type, and coating type, as well as uncontrollable factors,
such as the geometry and size of the target. Solutions should be situation-specific, and all of
the factors discussed above should be adjusted to optimize performance.
Waterborne coatings hold significant long-term potential for VOC reductions in wood
finishing. As this study demonstrates, water-borne coatings provide significantly less VOC
emissions as well as reduced materials usage, irrespective of spray equipment used. Operators
are urged to request information on the latest in water-based materials from their vendors.
439
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Figure 1. Transfer efficiency for all equipment types and coating systems
(using data from expert painter spraying doors).
Airless
HVLP air-assisted
Air-assisted airless
• 32% Solids Water-Bome
• 40% Solids Conv Var
D 30% Solids Nitrocel.
DID 25% Solids Nitrocel.
Conventional
10 20 30 40 SO
Transfer Efficiency (%)
60
70
440
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Figure 2. VOC emissions for all equipment configurations and coating
types (using data from expert painter spraying doors).
Airless
HVLP air-assisted
Air-assisted airless
HVLP-2
HVLP-1
Conventional
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lllllHlllllimiiiiiiiiiiimmiiimiiiiiimmiiiimiimiiiiimiiiiiimimiMiiiiim
iiiiiiiiiiiiiiiiiiiniiiiiiniiiiMiiiiiiiiiiiiiiiiiiiiiiiiM iniiiiiiiiiiiiiiiiNiiiiiiiiiiiiiiiiiiiniiiiiiii
• 32% Solids Water-Borne
• 40% Solids Conv. Var.
D 30% Solids Nitrocel.
OH 25% Solids Nitrocel.
2468
VOC Emissions (Ib VOC/lb solids applied)
10
441
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Figure 3. Spray time for expert and novice painters, with all equipment
types (using average data from all coating systems, spraying doors).
Airless
HVLP air-assisted
Air-assisted airless
HVLP-2
HVLP-1
Conventional
2345
Spray Time (minutes)
442
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REFERENCES
1. Lee, Abigail C. "Compliance Guidance for Autobody Repair and Refmishing Industry
Spray Coating Operations," Puget Sound Air Pollution Control Agency, 1991.
2. Joseph, Ron. "Getting into Compliance with Environmental Regulations for Paints,
Coatings, and Printing Facilities," International Coating Seminars, October, 1991,
Session 3-180, p.4.
BIBLIOGRAPHY
Allison, Melissa, Teresa Summers, and Cathy Troutman. Final Report for High Volume/Low
pressure Spray Gun Evaluation. Thomson Crown Wood Products, Mocksville, North
Carolina, 1992.
Baker Environmental, Inc. Current Potential Future Industrial Practices for Reducing and
Controlling Volatile Organic Compounds. American Institute of Chemical Engineers, Center
for Waste Reduction Technologies, New York, New York, 1992.
Dambek, Paul J., Kevin D. Kelly, Joshua M. Heltzer, Maria L'Annunziata, and Thomas M.
Smith. A Guide to Pollution Prevention for Wood Furniture Finishing. Prepared for U.S.
EPA Region 1, Capstone Project, Tufts University, Medford, Massachusetts, 1992.
EPA Guides to Pollution Prevention: The Paint Manufacturing Industry. EPA/625/7-90/005
(NTIS PB90-256405). U.S. EPA Risk Reduction Engineering Laboratory, Center for
Environmental Research Information, Cincinnati, Ohio, June 1990. 67 pp.
Hackney & Sons, Inc. Evaluation of High Volume/Low Pressure Spray Coating Equipment
Washington, North Carolina, 1990.
Kennedy, K.C. Transfer Efficiency of Improperly Maintained or Operated Spray Painting
Equipment, Sensitivity Studies. U.S. EPA Air and Energy Engineering Research Laboratory,
EPA-600/2-85-107 (NTIS PB86-108271). Research Triangle Park, North Carolina, September
1985.
Randall, Paul M. Pollution prevention methods in the surface coating industry. Journal of
Hazardous Materials, 29 (1992): 275-295, 1992.
443
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Appendix A
Material and Equipment Specifications
Table A. 1. Physical Properties of Coatings
Coating
Sealer (25%
solids)
Topcoat (25%
solids)
Sealer (30%
solids)
Topcoat (30%
solids)
Conv. Varnish
(40% solids)
Water-Bome
(32% solids)
Weight
(% solids)
26.07
29.72
25.81
28.07
35.79
30.86
VOC
(Ib/gaJ)
5.73
5.36
5.67
5.52
5.17
1.76
Density
(ib/gaJJ
7.74
7.62
7.62
7.67
8.06
8.24
Viscosity
(Zahn, #2)
33
45
37
28
33
30
Table A.2. Spray Equipment Specifications
Gun Type
Manufacturer
Model No.
Serial No.
Air Cap
Fluid Tip
Needle
Conventional
Airspray
Binks
2001
63PB
63B
563A
HVLP-1
Devilbiss
JGHV-530
*28
0.0425 inch
JGA402FX
HVLP-2
Accuspray
#10
3610155
fll
0.051 inch
0.051 inch
Air-Assisted
Airless
Grace
AA2000
(standard)
215/417*
(standard)
HVLP
Air-Assisted
Graco
AA2000
222608
215/417*
(standard)
Airless
Grace
Silver
415/417*
(standard)
• First number represents fluid Up used for spraying face frames; second Dumber is the tip used for doors
In addition to the spray guns and coatings described above, other equipment was needed to perform the tests. Pumps were
used with the air-assisted airless and airless configurations (Graco, Model 10:1 Monark with 1/4 inch fluid and 3/8 inch
air hoses and Model 30:1 president with 1/4 inch fluid hose, respectively). The fluid flow meter (Graco, CS A AFMapproved;
Class 1. Division 1, Model 224-222, Series F91 A, Serial #C148) was used with a 200 mAmp power generator and a pro-
pulse receiver module. The fluid pressure pot (5 gallon ASME) included 1.4 inch fluid line and a 5/16 inch air line. Fluid
temperature was measured with a thermometer (VWR Scientific Inc.. 61014-020).
444
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Appendix B
Calculations
Transfer Efficiency Transfer efficiency was determined on a mass basis using guidelines from ASTM
Method D5009-89:
Equation B.I TE = (100 x P) x 100 / (F x d x S)
where
TE = transfer efficiency (%)
P = mass of coating solids deposited on target (g)
F = volume of fluid delivered (ml)
d = density of coating (g/mi)
S = wt% solids of coating
Volatile Organic Compound (VOC) Content. VOC content was calculated using guidelines from ASTM
Method D3 960-90:
For solvent-borne coatings,
Equation B. 2: V = (100 - (S + X)) x d x 10
where
V§ = total VOC content (g/1) (organic volatiles)
S = wt% solids of coating
X = wt% exempt solvent of coating
d = density of coating (g/ml)
For water-borne coatings,
Equation B.3: VM =(V. x 100 x dj / (100 - (d x W))
where
Vw = total VOC content (g/l), based on coating excluding water
Vw = total VOC content (g/l), determined from calculation B.2
dw = 0.997 g/ml (density of water at 25°C)
d = density of coating (g/ml)
W = wt% \vater of coating
Coating density (d) and percent solids (S) were determined in the laboratory (see Appendix A, Table A. 1).
while water content (W) was taken from manufacturers' coating specifications.
VOC Emissiors. Emissions for each sealer + topcoat system were calculated with variables used in the above
equations (assumes 100% of VOC content in coating material is dispersed into air):
Equation B 4: E = [(V. x VOL.) + (V, x VOL,)] / P
where
E = VOC emissions for sealer + topcoat (g VOC/g solids applied)
V_ = VOC content of sealer (g/l)
VB = VOC content of topcoat (g/l)
VOL, = total volume of sealer used to finish target (1)
VOL, = total volume of topcoat used to finish target (!)
P = mass of coating solids deposited on target (g)
445
-------
446
-------
(The work described in this paper was not funded by the U.S. Environmental
Protection Agency. The contents do not necessarily reflect the views of the Agency
and no official endorsement should be inferred.)
YOU CANT ALWAYS JUDGE A PAINT SPRAY GUN
CLEANING SYSTEM BY ITS COVER
Michael J. Callahan
Project Engineer
Safety-Kleen Corporation
777 Big Timber Road
Elgin, IL 60123
and
John P. Kusz
Manager of Product Development
Safety-Kleen Corporation
777 Big Timber Road
Elgin, IL 60123
447
-------
ACKNOWLEDGEMENTS
The authors would like to gratefully acknowledge Ronald G. Draftz of
IITRI for his guidance, encouragement, and insight during this study.
448
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TABLE OF CONTENTS
Page
Introduction 450
Background 450
Test Plan 451
Test Equipment 453
Measuring Equipment 454
Active Test Procedures 455
Passive Test Procedure 457
Results 457
Conclusion 459
References 460
449
-------
INTRODUCTION
The reduction of VOC enissions from surface coating not only applies to
surface preparation and application, but to application equipaent clean-up as
well. Specifically, most paint spray gun cleaning systems use VOC's for
cleaning and, therefore, are another emission source which must be evaluated.
Many paint spray gun cleaning systems are currently in use throughout
industry, each with individual emission characteristics. The challenge
becomes selecting a system which cleans well, yet minimizes VOC emissions. A
simple approach to emission reduction might be to make sure the system uses a
low vapor pressure solvent and is closed during operation. However
intuitive, this approach may not always yield the desired results.
This paper -rill discuss a comparative study of VOC emissions between
two paint spray gun cleaning systems. One of the systems was defined as
'closed' (i.e. had a cover which remained closed during operation); the other
system was "open" (i.e. had no cover). A comparison was also made using
cleaning solvents with different vapor pressures to determine
solvent/cleaning system interaction regarding emissions.
BACKGROUND
This comparative study was sponsored by Safety-Kleen Corporation,
Elgin, Illinois, and conducted by IIT Research Institute (IITRI), Chicago,
Illinois, during June 1992. Safety-Kleen Corporation provides parts cleaning
services with associated recycling to the automotive aftermarket industry.
IITRI is a nationally recognized research and test institute which provides
advanced research and testing to government and industry covering a diverse
group of topics including environmental issues.
The comparative study was performed to demonstrate equivalent
compliance with California South Coast Air Quality Management District
(SCAQMD) Rule 11711, effective July 1, 1992. This rule requires that spray
paint gun cleaners limit emissions of volatile organic compounds (VOC's) that
are 'stratospheric ozone depleting or global-warming compounds.' The rule
provides specific guidelines for the use and disposal of solvents used for
spray paint gun cleaning systems (systems are defined as the cleaning unit
and its solvent).
The principal aspects of the rule which deemed the study include:
1. The-cleaning equipment must be 'closed' during operation except when
depositing and removing objects to be cleaned, and is closed during
nonoperation with the exception of maintenance and repair to the
cleaning equipment itself.*
2. The solvent shall have a VOC content of '950 grams or less of VOC per
liter of material and a VOC composite partial pressure of 35 mmHg or
less at 20»C (68'F).'3
3. Manufacturers, owners and operators may demonstrate equivalency (i.e.
equivalent compliance) for a spray paint gun cleaning system in lieu of
complying with these rules.*
450
-------
Specifically, the Safety-Kleen Model 1107 Spray Paint Gun and Equipment
Cleaner is considered by SCAQMD to be an open unit (i.e., does not have a
cover); therefore, it does not comply with the specific provision of Rule
1171. Additionally, the solvent currently used with Model 1107 in California
has a composite partial pressure of 96 mmHg, which exceeds the "35 mmHg or
lower" requirement of Rule 1171.
However, the "equivalency provision" of Rule 1171 allows for a
temporary exemption if it can be demonstrated that a "non-compliant" system
does not lose more solvent than a currently accepted system.
This study performed by IITRI was designed to determine whether the
Safety-Kleen Model 1107 had solvent losses comparable or less than hose of
closed systems using a low (less than 35 mmHg) vapor pressure solvent. A
Herkules GWR spray paint gun cleaner with a low vapor pressure solvent was
selected for this comparative compliance study.
TEST PLAN
A Safety-Kleen Model 1107 and a Herkules Model GWR were tested for both
active and passive solvent losses. Active solvent losses were those which
occurred from cleaning a spray paint gun according to the manufacturer' s
recommended cleaning procedure for each system. Passive solvent losses were
those which occurred as each unit would normally be stored between active
cleaning cycles.
Solvent losses for active and passive tests were determined separately
to permit total loss computation for any combination of active uses per day
with the corresponding times between use.
Solvent losses were determined by precise weight difference
measurements of each unit with its solvent. A highly sensitive precision
platform scale was utilized for all weighing. The test procedures used
standard weights to verify accuracy and sensitivity of the scale throughout
the testing.
Active test weighing were made immediately prior to the start of an
active test and at the completion of a cleaning cycle. The active cleaning
cycle for each unit will be discussed in detail under "Active Test
Procedures." Ten successive cleaning cycles comprised a single active test.
Passive test weighing were made daily for each unit. A single passive
test lasted for five contiguous days at ambient laboratory conditions.
Environmental conditions in the laboratory were not controlled;
however, temperatures, relative humidities and air velocities were
periodically recorded during testing. Each series of tests were conducted
virtually simultaneously in the same laboratory to minimize variations
resulting from ambient environmental variations.
Two primary solvents were tested: Safety-Kleen 5820 West5 (vapor
pressure - 95 mmHg) and Grow 4231 P.N.C^ (vapor pressure - 32 mmHg). Both
451
-------
solvents vere cross-tested in both units to verify representativeness and to
preclude test bias.
A third solvent, SK-East5, produced by Safety-Kleen, was also used for
cross-testing. SK-East has a vapor pressure of approximately 75 maHg.
A fourth solvent, cyclohexane (vapor pressure - 78 mnHg), was used in
one series of active tests in the Safety-Kleen Model 1107 unit as a control
solvent. Cyclohexane was used to establish active losses for possible future
product developments. This solvent is available from a number of sources as
a high-purity organic of known vapor pressure. Since this solvent is a
single organic chemical with no isomers, it provides a valuable link between
test results from this study and future experiments. It may also allow for
future comparative losses from multicomponent solvents by simply comparing
vapor pressures.
All testing was performed solely by IITRI staff at its principal
laboratories in Chicago, Illinois. All units were operated in strict
accordance with manufacturer's instruction manuals.^-^ In addition, all
active tests were conducted by a single operator to avoid inter-operator
performance differences.
The active test plan consisted of three test series (A through C) .
(See Table 1 below.) Series "A" compared the Safety-Kleen and Herkules units
using S-K East and Grow 4213 solvents, directly. Series "B" and "C" provide
similar cross comparison, but also permit comparison within a manufacturer's
unit.
TABLE I9
ACTIVE TEST MATRIX
Series Test
Cleaner Unit
Cycles
Test Function
Solvent
A
A
A
A
A
A
B
B
B
B
B
C
C
C
C
C
G
1
1A
2
3
4
5
6
7
8
9
10
11
12
13
14
15
26
Safety-Kleen(SKl)
Safety-Kleen(SKl)
Safety-Kleen(SK2)
Safety-Kleen(SK3)
Herkules (HI)
Herkules (2)
Safety-Kleen(SKl)
Safety-Kleen(SK2)
Safety-Kleen(SK3)
Herkules (HI)
Herkules (H2)
Safety-Kleen(SKl)
Safety-Kleen(SK2)
Safety-Kleen(SK3)
Herkules (HI)
Herkules (H2)
Safety-Kleen
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
Standard Clean
Repeat of Test 1
Standard Clean
Standard Clean
Standard Clean
Standard Clean
Replicate of Test 1
Compare to Tests 3&4
Compare to Tests 2&11
Compare to Tests 5&15
Compare to Tests 4&14
Compare to Tests 268
Compare to Tests 1&6
Replicate of Test 3
Replicate of Test 4
Replicate of Test 5
Control
SK-East
SK-East
5820 Vest
Grow
Grow
SK-East
SK-East
Grow
5820 Vest
SK-East
Grow
5820 Vest
SK-East
Grow
Grow
SK-East
Cyclohexane
Note: Test 1A repeated to correct procedural error.
452
-------
The passive test plan consisted of two test series, "D" and "E* (See
Table 2 below.)
TABLE 29
PASSIVE TEST MATRIX
Series
D
D
D
D
D
E
E
E
E
E
Test
16
17
18
19
20
21
22
23
24
25
Cleaner Unit
Safety-Kleen(SKl)
Safety-Kleen(SK2)
Safety-Kleen(SK3)
Herkules(Hl)
Herkules(H2)
Safety-Kleen(SKl)
Safety-Kleen(SK2)
Safety-Kleen(SK3)
Herkules(Hl)
Herkules(H2)
Days
5
5
5
5
5
5
5
5
5
5
Test Function
Standard Passive
Standard Passive
Standard Passive
Standard Passive
Standard Passive
Compare to Test 17
Compare to Test 18
Compare to Test 16
Compare to Test 20
Compare to Test 19
Solvent
SK-East
5820 Vest
Grow
Grow
SK-East
5820 Vest
Grow
SK-East
SK-East
Grow
TEST EQUIPMENT
Safety-Kleen Model 1107
Three identical new units, identified as SK-1, SK-2. and SK-3 were
utilized in the study. The Safety-Kleen unit is an air-powered, dual-remote
reservoir system consisting of a hemispherical cleaning/drain area with vapor
collection collar and vacuum operated final rinse purge. The dual remote
closed reservoirs, one for spent solvent and one for clean final rinse,
provide for quick return of solvent to separate containers, minimizing
potential for evaporation. The two air-driven solvent transfer pumps are
centrifugal type to minimize solvent vapor evolution. Solvent vapors in the
hemispherical cleaning drain area are removed through a perimeter collar
venturi system and ducted where deemed appropriate by the user. This collar
creates a slight negative pressure, keeping vapors contained and away from
the user. In addition, the collar vapor collector is interlocked with the
solvent pumps to preclude solvent pumping in the event of collar vapor
collector malfunction. A vacuum canister is also provided to capture solvent
during the final rinse purge stage. This canister is fitted with a
coalescing media that gathers the solvent vapor, condenses it and returns it
to the remote reservoir.
Herkules Model GVR
Two virtually identical, new units identified as H-l and H-2 were
utilized in the study. The Herkules unit is an air-powered, non-remote
reservoir system consisting of a rectangular solvent storage tank with
integral cleaning/drain area and a closable lid. The rectangular solvent
storage tank is nominally filled with five gallons of solvent. The tank is
also equipped with an external ball valve for draining during solvent change-
453
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out. The unit is equipped vith four equipment cleaning nozzles to
accommodate the cleaning of two spray paint guns vith paint cups
simultaneously. The solvent transfer pump is a positive displacement type
interlocked with the lid opening/closure.
Spray Paint Gun
Five identical, new paint spray guns were used for the study. One
paint spray gun was dedicated to each cleaner unit. The paint spray gun was
manufactured by Sinks, Model 98-1130. This particular paint spray gun was
selected because of its wide use throughout industry.
MEASURING EQUIPMENT
Platform Scale
A new, high precision Sartorius scale (Model F150) with a capacity of
150 Kg was utilized for all solvent weighing. The published scale
sensitivity was one gram over the full range of 0 to 150 Kg. The scale was
set up and calibrated by a factory-trained technician at IITRI prior to
testing. The sensitivity was verified subsequent to set-up and calibration.
Sensitivity and accuracy tests at load were performed using Class S-l
weights traceable to the National Institute of Standards and Technology and
six, 11.3 Kg barbell weights to provide loads slightly greater than the paint
spray gun cleaner weights. Additional standard (Class F) calibration weights
borrowed from the factory technician were used to produce loads over the full
range of the scale.
Weights were added to the scale ranging from one gram to 150 Kg noting
the values. A one-gram weight was added at each load to verify that the
scale could detect the one gram. The scale responded precisely to the one-
gram addition at all loads.
Scale Accuracy Verification
Throughout active and passive testing, the accuracy of the platform
scale was verified prior to and immediately after each cleaning unit weight
measurement. This was accomplished by placing the six 11.3 Kg weights in the
marked "footprint" and recording the value. Then a 50 g weight was added and
the value verified to become +50 g. Finally, all weights were removed; and
the scale was checked for "zero tare."
Auxiliary Scale Platform
The original platform of the Sartorius scale was too small to
accommodate the Safety-Kleen cleaning system. Therefore, a larger, aluminum,
auxiliary platform was placed over the existing platform and remained for the
duration of the testing.
The scale was sensitive to gross misplacement of the load, which may
have led to erroneous readings. Therefore, prior to testing, the auxiliary
platform was marked with the "footprint" of each cleaner and the barbell
454
-------
weights. The loads throughout testing were placed in the marked location
each time to preclude error.
ACTIVE TEST PROCEDURES
The following is a synopsis of the steps used to determine active
solvent losses for each unit.
Safety-Kleen Model 1107
1. Weigh the cleaner and components. Record value and time.
2. Don gloves and safety goggles. Disassemble the unused, clean spray gun
if it is not already apart, and place the parts in the cleaner bowl.
Turn unit on.
3. Fill the paint cup from the used solvent port for 7 seconds by counting
7 beats starting when the solvent begins flowing into the cup. Do not
start counting when the pump actuator switch is depressed, because
there is a delay of several seconds before the solvent flows. There
will be a solvent afterflow of several seconds when the foot actuator
switches released.
4. Brush the spray gun cup for 30 seconds as follows: a) Brush the inside
walls for eight seconds using a sweeping rotary motion; b) Continue
brushing the inside walls using a vertical stroke while rotating the
cup; c) Brush the lip and outer, upper collar using rotary strokes for
10 seconds. Keep track of time using the metronome beats.
5. Place the brush in the cleaner bowl and assemble the spray head to the
paint cup.
6. Shake the assembled spray gun containing the solvent for 15 seconds
using a pendulum motion.
7. Place the spray tip against the suction canister spout and squeeze the
trigger while pushing the suction canister up.
8. Maintain suction for 7 seconds.
9. Disassembly the spray gun. Place the spray head in the bowl and pour
the remaining solvent into the bowl.
10. Add clean solvent to the paint cup for 7 seconds.
11. Rotate the paint cup on its side 1 and 1/2 times slowly for
approximately 10 seconds to wet the inside paint cup surface,
simulating the entrainment of residual pigments/resins.
12. Pour the solvent into the bowl.
13. Place the paint cup into the bowl upside down to promote drainage.
455
-------
14. Invert the spray head and place its tube against the clean solvent
delivery tube of the cleaner. Squeeze the trigger while the solvent
flows for 7 seconds.
IS. Turn the spray head upright and flush clean solvent from the cleaner
onto the spray tip for 3 seconds while rubbing the tip with a gloved
finger.
16. Place the spray head into the bowl.
17. Remove and drape the gloves onto the bowl ledge and turn the unit off.
18. Disconnect the grounding clips and attach them to the cleaner so they
are part of the system weight.
19. Remove the exhaust hose from the hood and place it so the hood end
rests in the bowl.
20. Weigh the cleaner and components at exactly 4 minutes after the unit
was turned off. (This 4-minute wait period is included to permit time
for solvent evaporation from the bowl and components.) Record the
time.
21. Repeat steps 1-20 nine additional times.
22. Record system operating pressure, room temperature, relative humidity
and air speed on the data form during the tenth cycle.
23. Remove the cleaner and solvent cans after the tenth cycle of active
cleaning. Record the tare weight.
Herkules Model GWR
1. Weigh the cleaner and components. Record value and time.
2. Don respirator, gloves and safety goggles. Disassemble the unused,
clean spray gun, if it is not already apart.
3. Open the lid and invert the spray gun cup over the short nozzle.
4. Remove the trigger lock from the cleaner chamber and attach it so the
trigger remains in an open position.
5. Place the tube of the spray head onto a cleaner nozzle and close the
lid.
6. Turn the cleaner on for 60 seconds, timing the operation with a
stopwatch.
7. Adjust the solvent pumping rate to 2 cycles/second by matching the pump
beat to the metronome.
8. Turn off the cleaner and wait 5 seconds.
456
-------
9. Open the lid and remove the trigger lock, returning it to the
reservoir.
10. Shake excess solvent from the spray head into the reservoir. Hang the
spray head on the metal rod at the front of the cleaner.
11. Shake excess solvent from paint cup into the unit.
12. Close the lid, placing the paint cup upright on top of the lid.
13. Remove gloves and place them on top of the lid, and immediately start
timing a 4-minute wait period (to permit solvent evaporation from the
components outside the reservoir).
14. Disconnect the air compressor supply.
15. Weigh the cleaner and components in-place after exactly 4 minutes using
a stopwatch for time.
16. Repeat steps 1-15 nine more times.
17. Record system operating pressure, room temperature, relative humidity
and air speed on the data form during the 4-minute wait period of the
tenth cycle.
18. Remove the cleaner after the tenth cycle of active cleaning. Record
the tare weight.
19. Repeat standard weighing to verify scale precision and accuracy. This
completes a single active test consisting of ten data points for
solvent loss per cycle.
PASSIVE TEST PROCEDURE
The following is a summary of the steps used to determine the passive
solvent losses for each unit. This procedure was the same for both units and
consisted of the following steps:
1. Connect "fresh" solvent cans to the Safety-Kleen unit. Add five
gallons of test solvent to the Herkules unit.
2. Perform daily scale calibration verifications.
3. Weigh and record each cleaner. Record time of weighing.
4. Repeat measurements at approximately 24-hour intervals for five
additional days.
RESULTS
Active
The comparative tests show that the "closed* Herkules Model GWR with
Grow 4213 (33 mmHg vapor pressure solvent) lost an average of
457
-------
18.2 g/cycle during active cleaning. The Safety-Kleen Model 1107
"open" unit with 5820 West solvent (95 mnHg vapor pressure) lost an
average of 12.7 g/cycle during active cleaning. The Herkules unit with
Grow.solvent (32 mnHg vapor pressure) lost 1.4 times more solvent than
the Safety-Kleen unit during active test. (See Table 3 below.)
TABLE 39
ACTIVE LOSS RESULTS
Test
2
8
11
Test
4
10
14
Unit
SK-2
SK-3
SK-1
Unit
H-l
H-2
H-l
Solvent
5820 West
5820 West
5820 West
Average of
Solvent
Grow
Grow
Grow
Date
6-4-92
6-5-92
6-7-92
Safety-Kleen
Date
6-4-92
6-5-92
6-7-92
Average of Herkules
Cycles Total Loss.G
10
10
10
Units with
127
132
123
5820 Vest
Cycles Total Loss.G
10
10
10
Gun Units
202
162
182
with Grow
G-Loss/Cycle
12.7 +/-1-5
13.2 V-2.1
12.3 +/-1.1
12.7
G-Loss/Cycle
20.2 +/-1-9
16.2 V-0.9
18.2 +/-1-4
16.2
Passive
The tests showed that the Herkules unit lost an average of 1.82 g/hour during
the passive (non-cleaning) mode. The Safety-Kleen unit lost an average of
0.32 g/hr during the passive test period. The Herkules unit lost 5.7 times
more solvent than the Safety-Kleen unit during the passive period. (See
Table 4 below.)
TABLE 49
PASSIVE LOSS RESULTS
Test
17
21
19
25
Unit
SK-2
SK-1
H-l
H-2
Solvent Period Total Wt Loss
5820 West 9-14 Jun 92 32
5820 West 14-19 Jun 92 42
Average of Safety-Kleen Gun Cleaner Units
Grow 9-14 June 92 189
Grow 14-19 June 92 238
Average of Herkules Gun Cleaner Units
AVR G-Loss/Hr
0.27
0.37
0.32
1.57
2.07
1.82
458
-------
CONCLUSION
All of us recognize the importance of miniaizing VOC and toxic air
emissions in the coating industry -- not Just in the application of coatings
or surface preparation, but in cleanup operations as well. The methods for
potential reductions are as diverse as the processes themselves. For this
reason, simple rules and guidelines appear to be the most effective means of
reducing emissions. However well intentioned, the desired result --
significant emission reduction -- may not always be achieved.
As evidenced by the aforementioned comparative study results,
appropriate emissions reduction controls may already be in place, but
misunderstood. Just like a good book --a paint gun cleaner can't always be
Judged by its cover.
459
-------
REFERENCES
1. South Coast Air Quality Management District (California), Rule 1171,
"Solvent Cleaning Operations," adopted August 2, 1991.
2. Ibid, subparagraph (C)(2)(C), page 1171-8.
3. Ibid, subparagraph (C)(1)(C), page 1171-6.
4. Ibid, paragraph (c)(7), page 1171-10.
5. Safety-Kleen Material Safety Data Sheet No. 82343.
6. Grow 4213 Material Safety Data Sheet.
7. Safety-Kleen Model 1107 Instruction Manual.
8. Herkules Model GVR Instruction Manual.
9. Illinois Institute of Technology Research Institute (IITRI) "Final
Report--Compliance Study of the Safety-Kleen Model 1107 Spray Paint Gun
Cleaner," dated 6-29-92.
460
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SESSION 11
APPLICATIONS 2
PAPERS PRESENTED:
"Priority Manufacturing and Environmental Issues at Military Industrial Facilities"
by
John W. Adams
Richard S. Goldman
Jerry R. Hudson
National Defense Center for Environmental Excellence
Concurrent Technologies Corporation
Johnstown, Pennsylvania
"Low-V(X: Dual-Cure Aerospace Topcoat*'
by
Kevin E. Kinzer (Speaker)
Steven J. Keipert
3M Company
Corporate Research Laboratories
Si. Paul, Minnesota
"UV Pollution Prevention Technology in Can Manufacturing"
by
Erik T. Donhowe
Coors Brewing Company
Can Manufacturing
Golden, Colorado
"Pollution Prevention Opportunities in the Manufacture of Paint and Coatings"
by
Paul M. Randall
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, Ohio
461
-------
(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
PRIORITY MANUFACTURING AND ENVIRONMENTAL ISSUES
AT MILITARY INDUSTRIAL FACILITIES
John W. Adams. Richard S. Goldman, Jerry R. Hudson
National Defense Center for Environmental Excellence
Concurrent Technologies Corporation
1450 Scalp Avenue
Johnstown. PA 15904
1-800-CTC-4392
INTRODUCTION
Concurrent Technologies Corporation (CTQ, a not-for-profit company, operates the
Department of Defense's (DoD) National Defense Center for Environmental Excellence
(NDCEE) which is located in Johnstown, PA. The NDCEE provides a means of testing.
evaluating, and applying new and "stale of the market" environmentally acceptable technologies
in a low-risk industrial setting.
In 1990, Congress passed legislation that created the NDCEE. Sponsored by DoD's
Office of the Deputy Assistant Secretary (Environment) and managed by the U. S. Army
Material Command, the NDCEE was given the broad charter to systematically address industrial
challenges and identify and implement environmentally acceptable solutions.
The broad scope of our mission gives us the flexibility to lead government and industry
conversion to environmentally acceptable manufacturing technologies and to serve as a national
resource for environment-related technical and analytical support. As the Center's infrastructure
is put in place, it will gradually address:
• waste minimization.
• hazardous waste management,
• management of RCRA-type wastes,
• municipal-type solid waste and incineration issues,
• air pollution management,
• medical waste management,
• contaminated site remediation,
• demilitarization,
• recycling and recovery,
• water pollution management,
• nuclear waste management, and
• mixed waste management.
However, the initial thrust of the NDCEE will be that of Pollution Prevention —
specifically, demonstrating and exporting environmentally acceptable technologies to the DoD
and defense-related industries.
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HIGH PRIORITY ENVIRONMENTAL IMPACT REPORT
To ensure that the NDCEE focuses its attention on the nation's most significant
manufacturing and environmental problems first, the NDCEE has prepared a High Priority
Environmental Impact Report. For this report, industrial manufacturing technologies were
analyzed and ranked according to their potential for adverse environmental impact and relevance
to DoD- and defense-related industrial operations.
There is little information available that describes environmental discharges from DoD
manufacturing facilities. Consequently, the NDCEE used the Toxic Release Inventory (TRI)
industrial database, provided by the U. S. Environmental Protection Agency (EPA), for the
analysis of potential adverse environmental impact. The TRI is the most comprehensive
database available for industrial toxic air. water and solid waste discharges.
From the TRI listing of more than 300 chemical and chemical compounds, the NDCEE
defined "high priority chemicals" as those which are:
currently regulated by EPA,
• proposed to be regulated by EPA,
• identified as ozone depleting substances, or
• identified as potential, probable or known human carcinogens.
There were 68 chemicals in the TRI that met the criteria listed above. These chemicals
represent 71.4 percent of the total TRI-reported discharges in 1989. Industries that discharge
these "high priority chemicals" were classified according to three digit Standard Industrial
Classification (SIC) codes and were ranked according to the total discharge of the chemicals.
From the ranked listing of industries, those with operations similar or identical to manufacturing
processes at DoD industrial facilities (e.g., electroplating) were selected as high priority.
The five selected SIC Codes with their total TRI discharge are: 347 - Coaling, Engraving
and Allied Products; 367 - Electronic Components and Accessories; 371 - Motor Vehicles and
Motor Vehicle Equipment; 372 - Aircraft and Parts; and 373 - Ship and Boat Building and
Repairing. The total TRI discharges and "high priority chemical" discharges from these
industries are listed below. These industries will receive initial consideration by the NDCEE for
environmentally acceptable replacement technology demonstrations.
SIC TRI Total Discharge "High Priority Chemical" Discharge
347 69.4 million pounds 52.2 million pounds
367 74.1 million pounds 57.5 million pounds
371 161.7 million pounds 151.4 million pounds
372 56.0 million pounds 50.6 million pounds
373 30.1 million pounds 29.7 million pounds
The NDCEE also conducted telephone interviews with companies in each of the five
selected industries. Through these interviews, we were able to identify the top manufacturing-
464
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related environmental issues, the associated manufacturing processes, technologies being
considered to solve the environmental problems, and areas where the NDCEE could help.
CROSS INDUSTRY ISSUES
"High priority chemicals" discharges, which are common to three or more of the five
selected industry segments, represent over 99.7 percent of the "high priority chemical"
discharges. This indicates a high level of similarity in manufacturing operations among the five
selected discrete parts manufacturing industries. Based upon the "high priority chemical"
discharges of these industries, the following discrete parts manufacturing process activities can
be inferred for the five selected industry segments:
• painting • metal plating
• paint stripping • metal cleaning
The sheer volume and breadth of the TRI discharge data gives the impression of
fragmented and diffuse manufacturing-related environmental problems. The findings of this
report suggest otherwise, since many industries face the same problems. In this High Priority
Environmental Impact Report, the NDCEE has been able to distill these problems into the
following seven cross-industry manufacturing related environmental needs for the five selected
industries:
• demonstrate acceptable alternatives for paint removal chemicals,
• demonstrate acceptable alternatives for chlorinated and volatile organic
compounds used as metal cleaners and paint solvents.
• demonstrate pollution prevention strategies and technologies to reduce heavy
metal wastes.
• demonstrate acceptable alternatives to solvent based paint systems,
• implement a broader, more diligent effort for technology transitioning,
• provide worker training on pollution prevention practices and manufacturing
technologies, and. finally,
• leverage scarce financial and human resources to solve common problems.
RECOMMENDATIONS
Based upon the NDCEE's findings, eight preliminary recommendations are offered.
These recommendations are intended to stimulate discussion, upon reviewing this work effort,
among members of the NDCEE's Senior Board of Advisors and Executive Advisory Council, as
well as other interested individuals and organizations. Conclusions and further
recommendations from those discussions will be incorporated into future considerations of the
NDCEE.
The eight recommendations are specifically focused to action items for DoD and related
industrial facilities which, if taken, would enhance the overall quality standard of these industrial
facilities, as well as the overall environmental quality associated with the facilities and their
products. The key features of these recommendations are:
465
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1. Compile environmental discharge data from industrial facilities in a manner
which relates those discharges to the processes used at the industrial facility.
2. Demonstrate alternative technologies which can resolve environmental discharge
problems.
3. Conduct training programs on pollution prevention and alternative manufacturing
technologies.
4. Link product and process specification requirements to environmental problems.
5. Implement standard for environmental costs; such as disposal and treatment, as
well as "hidden" environmental costs; such as compliance, reporting, and
monitoring.
6. Establish cost standards for "hidden" environmental costs; such as compliance,
reporting, and monitoring.
7. Establish financial incentive programs to encourage pollution prevention
practices.
8. Enhance the awareness of, and benefits from, pollution prevention alternatives
through effective technology transitioning.
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
LOW VOC DUAL-CURE AEROSPACE TOPCOAT1
Kevin E. Kinzer
and
Steven J. Keipert
Corporate Research Laboratories
3M Company
3M Center 201-2N-19
St Paul, MN 55144
INTRODUCTION
The U.S. Environmental Protection Agency, as well as state
and local regulatory agencies are in the process of implementing
increasingly stringent controls on the emission of volatile
organic compounds (VOCs). These emissions are the primary cause
of photochemical smog and ozone pollution. Approximately seven
billion pounds per year of VOCs are currently released to the
atmosphere. A significant portion of this total is the result of
industrial painting and coating operations. Mandated reductions
in VOC emissions have led to the development of low or no VOC
coating formulations by the coatings industry. Unfortunately,
the reduced VOC content in these new formulations has often
required a sacrifice in performance, appearance, or ease of
application.
This paper describes development of the 3M dual-cure process
for photocured high-performance coatings. Dual-cure involves the
simultaneous polymerization of two monomer types to produce a
material consisting of two independent but interpenetrating
polymer networks (IPNs) . The properties of these IPNs are often
superior to either component separately. This novel cure
technology may allow significant reductions in VOC content while
maintaining the current performance characteristics of the cured
coatings. Demonstration of the commercial feasibility of this
technology is in progress in our laboratory with the support of
the U.S. Department of Energy Office of Industrial Technologies
under a cost-share contract. Performance testing is being done
in collaboration with the Boeing Defense & Space Group.
Aerospace topcoats have been selected for initial development
efforts. These protective coatings have very high requirements
for performance, appearance and durability. The materials
currently in use are two-part polyurethanes which are spray
applied. High resin viscosity requires the addition of a large
xThis paper was prepared for the U.S. Department of Energy,
Assistant Secretary for Conservation and Renewable Energy, under
DOE field office, Albuquerque, Contract No. DE-AC04-88ID12692.
467
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amount of solvent to reach sprayable viscosity. The aerospace
industry is under increasing regulatory pressure to find low-VOC
alternatives for these coatings. To achieve substantial VOC
reductions without a performance sacrifice has proven
challenging. A dual-cure system consisting of a two-part
polyurethane (polyol + isocyanate), combined with monomeric
acrylates is being evaluated as a possible low-VOC replacement
for urethane topcoats. The low viscosity acrylate component
reduces the solvent required, while enhancing the performance of
the cured film. Our goal is to produce a sprayable coating which
meets the high-VOC performance specifications, but at a VOC
content substantially lower than currently available
alternatives.
California has established upper limits for VOC emissions by
aerospace topcoats at 420 grams/liter ( SCAQMD rule 1124 ) .
Previous to these regulations, high performance polyurethane
topcoats typically had VOC levels of 650 grams/liter. It is
likely that the regulations currently in force in California will
eventually be adopted nationwide. To date, VOC compliant
aerospace coatings have required some relaxation of the
performance specifications established by the 650 g/1 materials.
Low-VOC coatings often have poorer appearance, are more difficult
to apply and cure more slowly, and lack the chemical resistance
of their high-VOC predecessors. Current low-VOC coatings are
also at or near the maximum VOC levels allowed by current
regulations. Traditional high-solids solventborne coatings
technologies are unlikely to allow reduction much below current
levels without an unacceptable decrease in performance.
DESCRIPTION OF THE 3M DUAL-CURE PROCESS
The basis of the 3M dual-cure process is a novel
photocatalyst system which allows light activated curing of a
variety of reactive monomers, including acrylates as well as
polyols and isocyanates to give urethanes. The catalyst is an
iron complex which can be decomposed to release catalytically
active iron species upon exposure to visible or ultraviolet
light. The photocatalyst structure and photodecomposition
mechanism are illustrated in Figure 1.
Dual-cure catalysts are unique in their ability to
photopolymerize polyols and isocyanates to produce polyurethane
resins. Previously, all of the known polyurethane catalysts have
been thermally activated. Light activation allows a degree of
control of the polymerization process not possible using thermal
catalysts. This characteristic can be utilized to provide a
practical method for the preparation of IPN polymers.
468
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Fe+
Fe*
Fc1
FIGURE 1.
Chemical structure of the dual-cure photocatalyst
and photo-decomposition mechanism.
An interpenetrating polymer network is formed when two
polymerization reactions, both which produce crosslinked
networks, occur within the same space, but there is no chemical
interaction between the two polymerization reactions. This
produces two enmeshed polymer networks, both continuous
throughout the entire solid, but with neither network connected
to the other by any chemical bonds. For example, in the system
chosen for aerospace applications, the two polymer systems are a
polyurethane and a polyacrylate. The polyurethane is formed by
an addition mechanism, while the polyacrylate is formed by a
radical mechanism. The two polymerizations occur simultaneously,
but independently of each other. The result is a solid composed
of two interpenetrating networks, both continuous throughout the
entire solid, but with no interconnections between the
polyurethane and polyacrylate networks.
Materials having IPN morphologies often exhibit unusual
mechanical properties. We have found in the polyurethane /
polyacrylate IPN system that these materials exhibit the best
properties of their constituent parts. For example, the tensile
property data shown in Figure 2 is for an IPN composed of a
strong but brittle polyacrylate, combined with a soft urethane
with good elongation properties. The tensile properties of each
component alone are shown for comparison. It can be seen that
the tensile strength of the IPN approaches that of the pure
acrylate, while at the same time maintaining most of the
elongation of the pure urethane. The combined effect produces a
material which is much tougher than either individual component.
This is shown in the chart for energy to break, which is the
integrated area under the stress / strain curve.
469
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Elongation at Break
£ i5o
• 100
}50
i o
u
Urclhane
Urclhan*/
AcrylaU
Composition
Acrylat*
Ultimate Tensile Strength
Ursthsne
Ursthans/
Acrylals
Composition
AcrylaU
2.5
? 2
j':
" 0.5
0
Energy to Break
Uralhano/AcrylaU
Composition
Acrylal*
FIGURE 2.
Tensile properties (elongation at break, strength
at break, and energy at break) of a polyurethane /
polyacrylate IPN material.
DEVELOPMENT OF DUAL-CURE AEROSPACE TOPCOATS
This enhancement of tensile properties led to consideration
of polyurethane / polyacrylate IPNs for aerospace applications
which have very demanding requirements for durability under a
wide range of conditions. Several other criteria were
established relating to requirements in the curing process. Cure
of the coatings must be activated with visible light exposure.
Ultraviolet lamps were not an option because of the strong UV
absorption exhibited by many common pigments. Fortunately, the
dual-cure catalysts absorb weakly in the blue portion of the
spectrum, which allows good cure of fairly thick pigmented films.
Cure must also occur in air at ambient temperatures. Nitrogen
inerting something as large as an airliner is not practical, and
the number of potential users having heated hangers is limited.
Normally, acrylate monomers do not cure well in air due to
inhibition of radical cure by oxygen. In an IPN system, however,
we have found that once the urethane cure has progressed
sufficiently, oxygen permeability is reduced to the point that
acrylate cure can occur. Cure has been demonstrated at
470
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temperatures as low as 60°F, with no detrimental effects. As in
conventional polyurethane coatings, complete cure is determined
by the slow cure of the polyurethane, and development of final
physical properties is obtained in approximately one week. Due
to rapid acrylate cure, and the ability to use catalyst levels
that would give unacceptably short potlife with conventional 2-
part urethanes, very short tack-free times are possible. Current
formulations require a 15 to 30 minute flash time for solvent
evaporation, followed by a 10 to 15 minute light exposure, at
which point the cured coatings are generally dry to touch.
A series of aerospace topcoat screening tests were selected
with the assistance of Boeing personnel. These were taken from
the Boeing commercial specification BMS 10-60, as well as
military specification MIL-C-83286. Tests were chosen which were
most critical to performance, and most difficult to meet
simultaneously. These included VOC content, reverse impact,
hydraulic fluid resistance (7 & 30 day), 60 degree gloss, low
temperature flexibility, water resistance, salt spray corrosion
resistance and pencil hardness. Accelerated weathering (500 hr.
Xenon Weatherometer) was later added due to questions about the
weatherability of non-urethane components.
This test series was used for the routine screening of
experimental formulations. Formulations were tested over a VOC
compliant water-reduced chromated primer (350 g/1 VOC), on
appropriately prepared aluminum substrates as detailed in the
specifications. All initial screening was performed on samples
containing titanium dioxide pigment at levels sufficient to
achieve good hiding power. Cure has also been demonstrated with
a variety of other colors. Reds appear to be the most difficult
to cure due to competitive light absorption at catalyst
absorption wavelengths, and cure speeds are slowed somewhat.
Initial samples were knife coated and cured with 15 minutes light
exposure. Testing was performed after allowing the samples to
age for 7 days at room temperature.
The optimum formulation at this point consists primarily of
polyurethane precursors, with a lesser amount of acrylate
monomers. The acrylate present appears to improve low
temperature and impact performance, as well as reducing the
viscosity of the formulation. Current performance and
specification requirements in the screening tests of several
formulations are shown in the table on the following page.
471
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Pencil Hardness
7 day Skydrol
30 day Skydrol
Reverse Impact
60° Gloss
500 hr weathering
Pot-life
Dry -time
Reference
Specification
BMS 10-60
MIL-C-83286
BMS 10-60
BMS 10-60
BMS 10-60
BMS 10-60
BMS 10-60
MIL-C-83286
Criterion
>2B
<2 pencil loss
>2B
80 in.-lb.
>90%
>70%
>4 hours
<2 hours
Dual -Cure
Performance
H
H{-0)
HB(-2)
45 in.-lb.
89%
77%
>4 hours
<1 hour
During optimization of the dual-cure formulation, the most
serious problems encountered were in achieving high initial
gloss, and satisfactory weathering performance. Low initial
gloss was found to result from incomplete acrylate cure at the
surface of the coating due to inhibition by oxygen. Stained
transmission electron micrographs of film cross-sections showed
depleted acrylate to a depth of several microns. This resulted
in post-cure film shrinkage, and surface roughening if pigment
was present. This problem was solved through the addition of co-
catalysts which improved surface cure of the acrylate.
Weathering improvements were achieved through reformulation of
the urethane components to more weatherable types, and the
addition of U.V. absorbers and light stabilizers. This improved
weathering performance at the expense of impact flexibility,
which fell to below specified levels. We are currently
investigating methods to improve coating flexibility without
sacrificing other performance properties.
Estimated VOC levels for initial dual-cure topcoat
formulations are in the 300 gram per liter range. We are in the
process of optimizing solvent composition and flow control
additives for spray application with high-volume, low-pressure
(HVLP) spray equipment. Final formulations will be evaluated in
a full set of qualification tests at a Boeing facility.
CONCLUSIONS
The dual-cure process shows promise for protective coating
applications requiring high levels of performance. . The IPN
polymer structure which is formed can provide enhanced
performance, often exhibiting the best properties of each
component. VOC levels substantially below those obtainable with
472
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conventional high-solids technologies appear possible.
Performance levels are approaching those required for aerospace
applications, and further optimization of formulations is in
progress.
RELATED PUBLICATIONS
M.C. Palazzotto, et al. , "Dual Cure Photocatalyst Systems", ACS
1990 National Meeting, Washington DC, High Solids Symposium, Paper
No. 206, August 30, 1990.
M.C. Palazzotto, et al., "Dual Curable Compositions for High Solids
Coatings", First North American Research Conference on Organic
Coating Science and Technology, Hilton Head, South Carolina,
December 3-7, 1990.
S.J. Keipert, "Dual Cure Photocatalyst Systems for Solventless
Coating", First Annual International Workshop on Solvent
Substitution, Phoenix, Arizona, December 4-9, 1990.
S.J. Keipert, et al., "Dual Cure Solventless Coating Process, Phase
I Final Report", Contract No. DE-AC04-88ID12692, Report No.
DOE/ID/12692-1 (DE92013677), February, 1992.
S.J. Keipert, et al., "Dual Cure Solventless Coating Process, Phase
II Final Report", Contract No. DE-AC04-88ID12692, Report No.
DOE/ID/12692-2 (DE93001351), October, 1992.
D.W. Osten, "Dual Cure Solventless Coating Process, Phase III
Semiannual Technical Progress Report", Contract No. DE-AC04-
88ID12692, Report No. DOE/ID/12692-3 (DE98001352), October, 1992.
S.J. Keipert, "Low VOC Photocurable Topcoat for the Aerospace
Industry", Third Annual International Workshop on Solvent
Substitution, Phoenix, Arizona, December 8-11, 1992.
R.J. DeVoe, D.C. Lynch, "Energy Curable Polyurethane Precursors",
U.S. Patent 4,740,577, 1988.
473
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474
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(The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency and no official
endorsement should be inferred.)
UV Pollution Prevention Technology in Can Manufacturing
Erik T. Donhowe
Coors Brewing Company
Can Manufacturing
17755 W. 32nd Avenue
Golden, CO 80401
INTRODUCTION
Conventional printing operations, including those in metal decorative printing, utilize solvent
based, or solvent-containing, ink and varnishes. As a result, conventional printing technologies
produce significant VOC (volatile organic compound) and HAP (hazardous air pollutant)
emissions. One newer technology, ultraviolet (UV) light initiated curing of coatings, has the
potential to provide significantly lower air emissions. The Coors Brewing Company Can
Manufacturing Plant has been utilizing this technology in full scale aluminum can production since
1975. This report details the significant pollution prevention provided by this technology, and
additional associated significant benefits in cost savings, energy conservation and practical
operation.
HISTORY
The Coors Brewing Company developed the country's first aluminum beverage can, a two-
piece aluminum can, in 1959, and was instrumental in the transfer of aluminum can production
technology throughout the beverage can industry. The Coors Can Manufacturing Plant, located in
Golden, Colorado, is the largest aluminum can manufacturing plant in the world, producing
approximately 4 billion cans a year. The plant currently produces aluminum cans exclusively for
the beer beverage market.
Coors Can Manufacturing worked in partnerships with several companies in developing the
UV curing technology for decorating aluminum cans. The initial push to convert to UV operation
was motivated by a desire to increase can printing speeds and to reduce energy consumption, in
addition to a desire to lower air emissions. In 1974, Fusions Systems Corporation and Coors
developed UV oven equipment which could rapidly cure UV inks. These UV ovens were installed
in full scale can production in 1975. Coors has worked with several chemical companies over the
years in developing practical UV inks and over varnishes. These chemical vendors have included
Borden, General Printing Ink, Akzo and Martinez Ink Company. The Coors plant is currently the
only plant in the country using the UV technology.
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TECHNOLOGY
The UV curing technology is used to apply the decorative exterior label on aluminum beverage
cans. The printing process is a "wet on wet" application, in which a clear protective over varnish
is directly applied on top of colored inks prior to UV curing. The UV chemicals are approximately
100% solids in content, with essentially zero solvent contents.
In the can printing process (Figure 1), colored UV inks are applied to printing plates; one plate
for each image color. A rubberized blanket wheel rotates, contacting the printing plates, picking
up each color in sequence. The end result is a complete color image on the blanket wheel Formed
"silver bullet" aluminum cans are carried on mandrels, rotate over the blanket wheel, and are
coated with the color image. The cans are then immediately carried over an over varnish wheel,
where the clear protective over varnish is applied over the ink. The cans are then carried on chains
to vacuum belts, where they are transported to the UV oven. The vacuum belt supports the cans
in proper geometry for curing through the UV oven. The entire process is very rapid: printing
speeds are approximately 1600 to 1800 cans per minute, and the UV oven cures the coatings in
approximately 0.7 seconds.
mandrel wheel
can faad
transfer unit
blanket
segment
Ink plate
overcoat unit
- o/o application roBar
FIGURE 1. UV Can Printer
476
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The alternative, conventional, technology used in other can manufacturing plants utilizes
thermal curing of inks and over varnishes. The thermal curing ovens are natural gas fired,
operating at 350 F or higher in order to achieve the ink and over varnish curing. Thermal ovens
are approximately 60 to 80 feet long, 8 feet wide and 25 feet high A long pin chain,
approximately 400 feet long, is used the transport the cans through the oven. The large
dimensions of the thermal oven, and the long transport chain, are required to provide the thermal
contact time and still achieve production rates of 1500 cans per minute or higher (1).
The UV ovens, in comparison, are approximately 9 feet long, 5 feet wide and 5 feet high. The
ovens operate at about 110 F, warmed slightly above ambient temperature due to the heat
evolution from the UV lamps. Cans are transported to and through the oven on a vacuum belt.
The UV oven contains between six and eight 10 inch, 300 watt/inch, microwave energized
mercury lamps. The lamps are positioned with parabolic reflectors in a geometry to focus
maximum illumination on the exterior surface of the aluminum cans. After an approximately 0.7
second exposure time, the cans leave the UV oven dry.
The print quality of the UV technology process is an important consideration. All cans
produced at the Coors Can Manufacturing Plant are now made with the UV process, and print
quality is comparable to that obtained with thermal curing. Similarly, color and gloss quality is
equivalent to that obtained from the thermal process. The over varnish is applied in order to
provide a protective coating over the decorative label, currently the abrasion resistance of the
over varnish is dependent on the film thickness of the over varnish. For a fully commercial can
market, with markets including all beverage categories in addition to the beer beverage, more
technical development is needed to formulate a higher abrasion resistance. This should be
achievable with newer formulations of UV over varnish (2).
The Coors Can Manufacturing Plant has in the past utilized a thermal technology can line side
by side with the main UV technology can lines. As a result, production operators have had the
opportunity to evaluate practical operations of the UV technology in comparison to the
conventional technology. The UV ovens can be started up much faster that thermal ovens (only a
5 minute start up time is required). The controls for the UV ovens are simpler. The newer UV
ovens utilize vacuum can conveyance belts, which are simpler, more reliable, and easier to
maintain than the long 400 foot pin chains which transport cans through hot thermal ovens. The
low operating temperature of the UV oven is also beneficial for front line production operation
and maintenance. Maintenance and parts costs for UV technology have been estimated to be
significantly lower than requirements for thermal technology (Table 1).
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TABLE 1. OPERATIONAL EFFICIENCY
Oven Size
Downtime
Maintenance
Parts
Process Control
Energy Use
10% of Thermal
Significantly Less
22% of Thermal
28% of Thermal
Simpler
55% of Thermal
In conjunction with the higher operational efficiency of the UV process, there are associated
financial savings. An estimated cost analysis has been performed for chemical usage, power
consumption, natural gas usage and equipment maintenance costs (Table 2). Chemical costs are
currently approximately 5% higher for UV inks and over varnishes. Natural gas is not required
for UV ovens, therefore the UV technology provides an estimated savings of $50,000 per billion
cans produced. As previously mentioned, thermal ovens require more maintenance. Therefore, an
estimated $90,000 per billion cans savings is provided with UV technology.
TABLE 2. OPERATING COSTS
(S1000/BILLION CANS)
CHEMICALS
ELECTRICAL
NATURAL GAS
MAINTENANCE
UV
1,076
60
40
THERMAL
1,025
57
50
130
478
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The total energy consumption requirements have been compared for the UV and thermal
technologies (Table 3). Estimates in units of millions of BTUs per billion cans are provided. The
estimates include both BTU values obtained directly from natural gas (thermal ovens) and BTU
values for the electrical power consumption Since no natural gas is used with UV ovens,
approximately 15,400 million BTUs are saved per billion cans. Both types of ovens require similar
levels of electrical power. Electrical power consumption is slightly higher for UV than for
thermal, due to the energy demands of the UV lamps, however the thermal ovens also require
comparable electrical power to run blowers and can chain conveyors.The net energy savings with
UV technology is estimated to be 14,880 million BTUs per billion cans produced.
TABLES. ENERGY SAVINGS
(MMBTU/BILLION CANS)
UVOVEN
THERMAL ENERGY
OVEN REDUCTION
NATURAL GAS
ELECTRICAL
10.500
15,400
9.960
15.400
-520
TOTAL
14.MO
ENVIRONMENTAL IMPACT
Over the past two years, a series of procedures have been conducted at the Can Manufacturing
Plant to estimate the environmental impact of the UV printing technology. The procedures ranged
from the laboratory analysis of ink and over varnish VOC contents to full EPA protocol stack
testing This analysis has provided a comparison of the UV to the thermal conventional
technology.
An initial estimate was made utilizing ASTM method 24 testing of the thermal and UV inks
and over varnishes. Method 24 is the approved method for determining VOC content in paints
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and other surface coatings. The method was modified to add UV curing prior to the gravimetric
analysis in the procedure, in order to accurately reflect the UV initiated cross-linking of the inks
and overcoats. Results were expressed in tons of VOCs per billion cans. The data (Table 4)
indicates that the current generation of UV coating, UV acrylate, contains 1.68 tons of VOC per
billion cans, which is substantially lower in VOC content that the current water based thermal
coating, which contains 28.9 tons per billion cans. A newer UV coating product with potential
production application contains an even lower VOC content of 0.22 tons per billion cans.
TABLE 4. COATING VOC CONTENT
(MODIFIED METHOD 24)
TONS/BILLION CANS
WATERS ASED
W ACRYLATE
UVEFOXY
An initial estimate of actual stack emissions was conducted on the UV oven exhaust from a can
line running at full production rates. The method used was EPA Method 18, a general method
allowing the use of various procedures for sampling and instrumental analysis. The conditions
chosen were charcoal tube absorption followed by solvent desorption and GC/MS analysis. Based
on the UV chemical formulations, specific target compounds were selected. The results of this
screening test (Table 5) indicated that target compounds were not detectable to the detection
limits of I ppb (w/v). Corresponding emission calculations in tons/year of VOCs indicated that
emissions were less than 0.3 tons/year for each target, and a total less that 1.5 tons/year.
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TABLE 5. VOC EMISSIONS ESTIMATE
(EPA METHOD 18 SCREEN)
COMPOUND ug/L TONS/YR
n-butanol
ethoxyethanol
o-xylene
ethoxy ethoxyethanol
benzophenone
< 5
< 5
< 5
< 5
< 5
TOTAL =
< 0.3
< 0.3
< 0.3
< 0.3
< 0.3
< 1.5
Additional estimates of VOC emissions were obtained from Material Safety Data Sheet
(MSDS) data for the VOC content of each coating product (Table 6). Comparisons were made
for the over varnish (overcoat), ink and bottom varnish (bottom coat) applications. The
application of a varnish on the bottom of the cans was estimated for the UV process as a
conservative comparison, even though bottom coat is not applied currently in the UV process.
Very significant differences are evident between the thermal and UV processes with this estimate.
The VOC emissions are again based on a tons/billion cans basis, as this is the index generally used
for regulatory control. A total of 28.5 tons of VOCs are estimated to be released as VOCs with
the thermal process in comparison to a conservative maximum emission of 1.6 tons/billion cans
for the UV process.
A similar comparison (Table 7) was made for hazardous air pollutants (HAPs). Almost half of
the VOC content in current thermal coatings are glycol ethers, which are listed hazardous air
pollutants in the new Clean Air Act regulations. It is pertinent, therefore, that, with upcoming
higher scrutiny and tighter controls for HAPs, a technology with lower HAP emissions will be
highly preferred. Estimated HAP emissions from the thermal technology are 14.3 tons/billion
cans, and estimates from MSDS data indicate that there are no HAP emissions at all for the UV
technology.
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TABLE 6. ESTIMATED VOC EMISSIONS
(MSDS DATA - TONS/BILLION CANS)
THERMAL UV
OVERCOAT
INK
BOTTOM COAT
TOTAL
26.5
0.8
1.3
28.5
1.3
0.2
0.1
1.6
TABLE 7. ESTIMATED HAP EMISSIONS
(MSDS DATA-TONS/BILLION CANS)
THERMAL UV
OVERCOAT
INK
BOTTOM COAT
TOTAL
13.2
0.4
0.7
14.3
0.0
0.0
0.0
0.0
482
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Proposed HAP regulations at the federal regulatory level, and current HAP regulations at the
state regulatory level, require emissions reporting at very low reporting thresholds. Current
OSHA standards stipulate MSDS reporting thresholds for chemicals at 1% and 0.1%
concentrations. This data was judged to be too inaccurate for appropriate HAP regulatory
reporting needs. Therefore, protocol testing was conducted on the UV process at the Coors Can
Manufacturing Plant. This detailed stack testing was conducted in order to fully comply with our
current state HAP reporting thresholds at SO and 100 pound/year levels The data from the
protocol stack testing (Table 8) indicated that extremely small levels of HAPs are emitted The
compounds detected were suspected to be present in the UV chemicals as trace constituents. It is
important to note that only 360 pounds are emitted for the entire facility per year. The UV
technology is therefore essentially a zero HAP process.
TABLES. HAP EMISSIONS
(PROTOCOL TESTING)
HAPS
MEK
XYLENES
METHANOL
TOLUENE
FORMALDEHYDE
TOTAL
LB/YR*
67.3
429
72.1
124.7
53.4
360.4
" Enbre F«c*»y
The Coors Can Manufacturing Plant implemented the UV printing technology in 1975, and the
plant is the only can manufacturing plant using this technology. If the conversion had not taken
place in 1975, significant emissions of VOCs and HAPs would have occurred. The
implementation of the UV operation has thus had a very significant pollution prevention effect.
The magnitude of this is depicted in Figure 1. The upper part of the chart is the potential
emissions from a thermal process; the small lower area of the chart depicts the worst case
estimate for UV technology emissions.
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Approximately 80 to 100 tons of VOCs would have been emitted each year since 1975. The
sum of these savings in potential emissions is 1,640 tons of VOCs. This comparison is
conservative, since it is based on VOC contents of current UV and current thermal coatings, and
earlier thermal coatings were much higher in solvent content.
FIGURE 2. CUMULATIVE VOC REDUCTIONS
VOC* (TONS)
140
120
100
W
60
40
20
0
1975
1977
1979 1961 1963 1965 1967 1969 1991
IUV 0 THERMAL
In addition to VOC and HAP emissions, CO2 emission estimates were compared for the two
technologies. The CO2 estimates are calculated from EPA conversion factors for natural gas
combustion, and also for CO2 emission factors for electrical power production. The CO2
estimates for the UV technology therefore include the CO2 emissions which occur at the power
plant generating the electrical power used for the UV process. The annual emissions savings at the
Coors Can Manufacturing Plant due to the UV technology are currently estimated to be 107.6
tons of VOCs, 57.0 tons of HAPs, and 4,216 tons of CO2
If the UV technology were transferred nationally, there would be subsequent notable pollution
prevention impacts. Estimates for a national technology impact have been calculated by
comparing the annual production of approximately 4 billion cans/year at the Coors Can
Manufacturing Plant to the national production rate. The national production of aluminum
beverage cans is approximately 100 billion cans/year (3).
Pollution prevention estimates (Table 10) are 2,690 tons/year of VOCs, 1,425 tons/year of
HAPs, and 105,400 tons/year of CO2 emissions. These impacts are even more substantial taking
into account the regional clustering of can manufacturing plants in several states. The
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implementation of UV technology could therefore have a significant regional pollution prevention
impact.
TABLE 9. EMISSIONS SUMMARY
ENTIRE FACILITY - TONS/YR
VOC
HAP
CO2
ANNUAL
ACTUAL (UV> THERMAL REDUCTIONS
6.4
0.2
4200
114.0
57.2
8416
107.1
17.0
4210
TABLE 10. EMISSIONS SUMMARY
NATIONAL POTENTIAL • TONS/YR
ANNUAL
ACTUAL (UV> THERMAL REDUCTIONS
VOC
HAP
CO2
160
105,000
2850
1430
210.000
1426
106,400
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SUMMARY
The UV curing technology in use at the Coors Can Manufacturing Plant has been a proven
technology for the past 18 years. Very substantial benefits are evident with this technology in very
low, or zero, VOC and HAP emissions, and much lower CC>2 emissions as compared to the
alternative thermal curing technology. Estimates also indicate that the UV technology consumes
less energy than the thermal technology, and that the UV technology is operationally more cost
effective than the alternative technology. The UV technology at the Coors plant is currently
dedicated to a beer beverage market, and can product quality is fully acceptable for this market. A
higher abrasion resistance can coating is currently desired for other beverage markets. Therefore
newer generation UV over varnishes with higher abrasion resistance ratings may have to be
investigated or implemented in order to fully convert this technology. In light of the significant
pollution prevention effects from this technology, and more stringent upcoming air regulations, it
would seem to be desirable to overcome these remaining minor obstacles.
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REFERENCES
1. Crabtrce, T.A. RadTech '88 North America, pp. 231-239. 1988.
2. Milton-Thompson, A. RadTech Report Vol 7 (2). pp. 18-23 1993.
3. Beverage World's Periscope. Vol 112(1538). p. 17. 1993
487
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488
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POLLUTION PREVENTION OPPORTUNITIES
IN THE
MANUFACTURE OF PAINT AND COATINGS
BY
Paul M. Randall
US. Environmental Protection Agency
Office of Research & Development
Risk Reduction Engineering Laboratory
Pollution Prevention Research Branch
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
(513) 569-7673
FAX: (513) 569-7549
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Abstract
The paints and coatings industry is rapidly changing to meet environmental and
economic pressures. Some of the changes include new coating formulations, higher
performance finishes with improved properties, continued development of new technologies,
and new application methods with improved transfer efficiencies. In order to control costs,
improve productivity and quality, and protect the environment, more paint companies are
turning to pollution prevention as the cornerstone of their waste management programs. Paint
pollution prevention has been incorporated into many corporate total quality management
(TQM) strategies.
There are many pollution prevention methods for the paint manufacturing industry
which vary from very simple, inexpensive measures to new, expensive plant/equipment. The
methods, techniques or programs can generally be classified as either recycling or source
reduction and may involve material substitution, process or equipment modification, revised
operating practices, operating procedures (such as waste stream segregation), personnel
practices (such as operator training), loss prevention practices, or accounting practices. This
paper will provide an overview of these practices in-place at particular manufacturing
facilities to reduce wastes and associated costs, to be a more competitive industry that must
still maintain quality and performance of its products.
The information in this article has not been subjected to Agency review. Therefore, it
does not necessarily reflect the views of the Agency.
Introduction
The role of the paint and coatings industry in the U.S. economy is pervasive. Paint
and coatings are essential not only for the decoration and protection of the surfaces of many
new industrial products but also for the maintenance of existing structures and products, such
as homes, vehicles, machinery and equipment, buildings and factories. Without these paint
and coatings, many of our durable and non-durable goods would have a decreased life-span.
The manufacture of paints and coatings is big business with shipments exceeding
$115 billion (1989) in the U.S. alone. Americans consume approximately 1 billion gallons
annually, of which, approximately 50 percent is represented by architectural coatings. The
annual growth rate for the industry is expected to be 1 percent (1991-1995). The product
coatings area accounts for about 36% of (1991) shipments and special purpose coatings with
16% of 1991 shipments. The nine industries that are major consumers of paint and coatings
include: (1) automotive; (2) trucks/buses; (3) metal cans; (4) farm machinery/equipment; (5)
construction machinery; (6) coil coating; (7) wood furniture/fixtures; (8) metal
furniture/fixtures and; (9) household appliances.
The driving forces behind the changes in paints and coatings continue to be product
performance improvements and environmental regulations associated with new materials.
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Paint and coating formulators as well as upstream raw material and resin suppliers are
evaluating the components in their products and processes, changing the constituents to
achieve desired performance of their coatings while also meeting new environmental rules.
Paint producers undertake their own product research and development but also look to
technological leaders to meet reformulation needs.
In addition to addressing product reformulation impacts, paint and coatings
manufacturers are also examining their production methods to look for ways to control costs.
To achieve improved productivity and quality, as well as protect the environment, more paint
companies are turning to pollution prevention as the cornerstone of their waste management
programs. Pollution prevention methods generally involve material substitution, process or
equipment modification, modified operating practices and procedures (such as waste stream
segregation), personnel practices (such as operator training), loss prevention practices or
accounting practices. This paper will provide an overview of the paint industry's efforts to
reduce wastes and reduce costs, while at the same time provide quality paint and coatings
products which meet the performance requirements of a diverse customer base.
Review of Raw Materials
The primary raw materials used by the paint and coatings industry include resins,
pigments, solvents and additives. In the production of liquid paints (latex and solvent-based),
production methods are primarily physical, that is, there are no chemical reactions or
conversions of raw materials to other products and byproducts. Paint is typically a dispersion
of a finely divided pigment in a liquid composed of a resin or binder and a liquid vehicle.
There is a wide variety of synthetic resins used in coatings (i.e. acrylic, alkyd, vinyl,
epoxy, polyester, urethane, etc). The synthetic resins are long chain polymers that may be
linear, branched, or cross-linked or some combination of these forms depending on the
functionality and reactivity of the monomers from thick they are formed. Resins are selected
based on many factors but primarily on application and performance.
The liquid portion varies depending on whether the paint is solvent based or water-
based. Typical organic solvents include methyl ethyl ketone, methyl isobutyl ketone, toluene,
and xylene. Water based, water dispersed, or water soluble coating systems substitute water
for some or all of the volatile organic solvent.
Manufacturing Process Wastes
In the manufacture of paint and coatings, paint manufacturing facilities generate
different waste streams. Typical wastes include:
e Raw material packages, bags, containers from unloading materials into mixing vessels.
o Pigment dusts from unloading of pigments into mixing vessels
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o Solvent emissions from storage tanks, leaks, and open process equipment
o Off-spec paints
o Spills
« Rinse water from equipment cleaning using water or caustic solutions
o Paint sludge from equipment cleaning operations
o Filter cartridges with uhdispersed pigment, paint and/or resins.
Paint industries handle this waste by either on-site recycling, off-site recycling or
treatment/disposal. On-site recycling involves the selected reuse of raw materials or wash
materials in new batches of paints and coatings. Recycling of usable materials within the
plant reduces the amount of new virgin raw materials needed per batch, resulting in
significant reductions in operating aw well as waste management costs. On-site recycling of
solvents may include distillations. Many companies send their wastes to an off-site recycler,
though more and more of these companies are recycling their own wastes to reduce costs and
improve operating efficiencies. Treatment/disposal operations available to paint
manufacturers include incineration or land disposal. Typically, many paint manufacturers
send solvent-containing wastes off-site to a cement kiln for inclusion in a fuels-blending
program (for thermal destruction).
Of the wastes generated in a typical paint manufacturing facility, equipment cleaning
wastes are by far the largest in volume, collectively accounting for some 80% of the
industry's wastes. Process equipment and tanks are routinely cleaned to prevent product
contamination and/or restore operation efficiency. Equipment that may need cleaning include
high speed dispersion mixers, sand mills, colloid mills, rotary batch mixers and blenders,
drum mixers and roller, grinding equipment, mixing vessels, pumps & motors, filters and
strainers, filling and capping equipment and packaging equipment. Many paint manufacturers
are rinding pollution prevention provides significant opportunities for reducing wastes.
Pollution Prevention Methods for the Paint Manufacturing Industry
Pollution prevention, or the method of preventing polluting through source reduction
and recycling, is becoming a cornerstone of most progressive waste management programs.
Reducing wastes to remain competitive has been an important ingredient for successful
business in the past and it will be absolutely essential in the future. So controlling and
optimizing all parts of the manufacturing process is critical to reduce costs, improve processes
and continue to be competitive and profitable.
Pollution prevention approaches can be broken down into the following categories:
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o Source reduction • Good manufacturing practices, production process changes,
and input material changes.
o Recycling - use and reuse of wastes, reclamation (on-site, off-site recovery).
Good manufacturing practices generally means better procedural or institutional
policies and practices and can include waste segregation, personnel/employee practices,
procedural measures, loss prevention practices, and accounting practices. Personnel practices
can include upper management initiatives, employee training, and/or employee incentives.
Careful attention to production and maintenance operations is important to reduce spills and
minimize off-spec products. Making employees more aware of the impact of waste on the
company's costs as well as the impact on the environment.
Procedural measures can include better documentation, better material and handling
storage, material tracking and inventory control and better production scheduling techniques.
For example, since thousands of different paint formulations require special production runs,
more effective planning and production scheduling may be needed. Paint production,
although a vital phase, must intermesh smoothly with purchasing, formulation sales,
accounting, inventory, personnel management etc. to make it profitable. Production planning
and scheduling may consist of a scheduling board listing the batches to be run on each piece
of equipment and the expected starting and finishing times. It aids maintaining adequate
inventory of active raw materials without overstocking and permits attainment of delivery of
commitments to customers. Also, if practiced effectively, it helps level peaks and slumps in
production during surges of short delivery orders or establish "downtime" of each piece of
equipment while keeping check of overall efficiency and ensuring maximum equipment
utilization.
In loss prevention practices, better awareness of spill prevention and in house
preventive maintenance programs may be required. Accounting practices should incorporated
better apportionment of waste management costs to the departments that generate wastes.
Most off-spec paint is generated by small shops that produce specialty paints. Since
the production costs for specialty paints are typically high, most off-spec paints are reworked
into marketable products. However, the cost of reworking off-spec paints are avoided if
better trained and supervised operators as well as quality control are reinforced so that
generation of off-spec paints are avoided.
Obsolete paint products and customer returns can be blended into new batches of
paint. Obsolete products result from changes in customer demands, new superior products,
and expired shelf life. Careful production planning and inventory control can reduce
obsolescence resulting from expired shelf life. Also marketing policies such as discounting
older paints can help reduce the amount of obsolete products.
There are many other ways of applying good manufacturing and operating practices.
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For example, soliciting employee suggestions may uncover methods to make changes
especially since the operators understand the process operations. Quality improvement teams
make significant improvements to the quality of the product, optimize the process, improve
efficiency and productivity, and reduce the wastes in the process. Furthermore, incentives,
rewards, and bonuses can be used to support pollution prevention programs and reduce
wastes.
Improving the efficiency of a process can significantly reduce waste generation.
Available techniques range from eliminating leaks from process equipment to installing state
of the art production equipment. This pollution prevention category includes improved
operation and maintenance, procedural changes, and equipment modifications.
Equipment cleaning wastes represents the largest source of waste in a typcial paint
plant. A method that reduces the need or frequency of tank cleaning or allow for reuse of the
cleaning solutions is the most effective way to reduce wastes.
The use of mechanical techniques, such as rubber wipers, reduces the amount of paint
left on the tank walls of a mix tank. Wipers are used to scrape the sides of a cylindrical mix
tank (flat or conical). Equipment cleaning is usually a manual operation so this process may
be justified based on rescued labor costs as well as reduced usage of cleaning solution
(another savings). High pressure spray heads and limiting wash/rinse time systems can be
used in place of regular hoses to clean water-based paint tanks. Studies show that high
pressure wash systems can reduce water use by as much as 80 to 90 percent.
Teflon line tanks are sometimes used to reduce wall adhesion and improve drainage.
This method is usually applicable to small batch tanks. A plastic or foam "pig" is used to
clean pipes. This pig device is forced through the pipe from the mixing tanks to the filling
locations, using nitrogen or some other inert gas to propel the pig.
Manufacturing procedures may be improved. For example, a paint facility's wash
solvent from each solvent-based paint batch may-be separately collected and stored. When
the same type of paint is to be made, waste solvent from the previous batch is recycled and
used in place of virgin solvent.
Countercurrent rinsing processes can be applied to those plants with sufficient tanks
space. This technique is used to recycle "dirty" solution initially to clean tanks and then is
followed by a "clean" solution to complete the rinse cycle. The level of contamination builds
up more slowly with the clean solution than the dirty reused solution thus extending cleaning
solution life.
Spills due to accidental or inadvertent discharges usually occur during transfer
operations or as a result of equipment failure. For example, during a loading operation, a
spill may occur from a leaking fill hose or fill line connection or leaking valves, piping, and
pumps. Sometimes spills occur from overfilling of tanks or due to improper or
494
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malfunctioning overflow alarms. Improving regular equipment inspections and training
programs prevent these spills from occurring as well as improved instrumentation and
automation and efficient cleanup methods if spills do occur.
Small amount of dry materials used in paint may remain in bags. Capturing the
pigments for reuse through vapor traps helps reduce waste problems. The availability of
these materials in slurry or paste form eliminate problems of disposing of waste bags or
packages. Empty containers of liquid raw materials that contain hazardous compounds are
typically cleaned or recycled back to the original raw materials manufacturers or to a local
drum recycler. This avoids the costs of disposing of the containers.
There are two major types of air emissions in paint manufacturing plants: VOCs and
particuiates. VOCs may be emitted from the conservation vents on top of the bulk storage
tanks of resins and solvents and from the use of open processing equipment such as mix
tanks. Since most process equipment is of open design, reducing VOCs from equipment
could require substantial capital expenditure in retrofit costs. Closed vessels with overhead
refrigerated condensers will require considerable capital requirements which most paint
manufacturers cannot afford. In fixed roof design, maintained conservation vents, conversion
to floating roof, use of nitrogen blanketing to suppress emissions or the use of refrigerated
condensers. Implementing these options can result in cost savings to the paint and reduced
raw material losses.
Dusts generated during handling, grinding, and mixing of pigments may be hazardous
and therefore dust collection equipment such as hoods, exhaust fans, and bag houses are used.
Use of pigments in paste form instead of dry will reduce or eliminate dust generated from
pigments. The drums can be recycled.
i
Also, a major advance in paint manufacturing is the growing use of electronic control
devices and batch automation. The intent is to avoid operational accidents, improve quality,
and production efficiency, and the overall accuracy of the batch. The effect should be less
waste generated. Computer use is increasingly being used for materials allocation and
inventory control as well as preventive maintenance scheduling. As the costs associated with
plant automation equipment decreases, the use of automation in paint manufacturing facilities
will increase.
Case Studies
Four companies that have received special recognition for their pollution prevention
programs by industry are Moline Paint Manufacturing co. in Moline, IL, Vanex Color, Inc. in
Mt. Vernon, IL, Red Spot Paint & Varnish Co. in Evansville, IN, and Jamestown Paint
Company in Jamestown, PA. Moline reported a 50% reduction of hazardous wastes in less
than five years and reported savings of over $140,000/yr in disposal and raw materials costs.
Moline's program included on site recovery for reuse, process modifications, statistical
process control techniques of waste generation, improved housekeeping, employee
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participation, and reuse of hazardous wastes off-site in a waste-to-energy recovery program.
Vanex Co. used source reduction and recycling methods. Ethylene glycol, a free-
thaw stabilizer in latex paints, has been replaced with propylene glycol which exhibits less
health concerns. Wash solvents generated from the production of solvent-based paints is
recycled, when possible, into subsequent solvent-based paint batches. Unusable wash solvent
was sent to a cement kiln. Approximately 80% of all wash solvent was recycled in-house
resulting in savings of $15,000/yr.
Red Spot Paint & Varnish Co. initiated a full waste-tracking system to identify the
exact point of origin of each unit process waste, which was then sampled and analyzed to
determine its potential for recycling and reuse. The program concentrated on motivating
employees to become more waste conscious and to train them in waste reduction methods and
procedures. Through their program, the company saved more than $1 million by incorporating
a number of seemingly insignificant equipment additions and a few equipment and tool
modifications, which represented over 60% savings.
Jamestown Paint Company incorporated pollution prevention into their total quality
management (TQM) program by focusing on waste minimization, quality control, customer
satisfaction and increased profitability. Employees drawn from various operational and
administrative areas formed process improvement teams, and each team was given specific
objectives and charged with clearly defined improvement goals. Results a year after
implementation of the program showed a reduction in hazardous waste by more than 75% and
savings in excess of $100,000.
Pollution Prevention Techniques Applicable to Paint Manufacturing
The following summarizes some of the pollution prevention techniques paint
manufacturers are using:
Source Reduction
o Schedule compatible solvents in sequence to reduce truck loading and drum flushing
need.
o Schedule like colors through equipment.
o Install dedicated lines where feasible to reduce flushing.
0 Segregate line and pump flushings to produce low-grade thinners suitable for cleaning
purposes.
0 Equip bulk storage tanks with vapor return lines.
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0 Install collector to remove pigment dust from manufacturing area.
« Increase drum inventories of high volume products to reduce changing of products in
the drumming line.
o Replace wastewater treatment lagoons with new system incorporating concrete cells
covered by fiberglass dome, equipped with venting of off-gases to destruction by
burning.
° Eliminate dry bags by converting to titanium dioxide slurry system pumped directly to
mixer.
° Install closed filtration systems to reduce VOC emissions (losses); also closed filter
systems can eliminate residues once left in filter bags.
0 Install odor/vapor capture systems on bulk solvent storage tanks, resin tanks and
manufacturing tanks.
o Eliminate all obsolete materials for possible rework.
Reuse/Recycling in manufacturing process
o Recycle wash solvent whenever possible; to facilitate recycling, setup holding tanks
for recovered washwater and wash solvent, segregate by color and/or product line;
reuse wash solvents from one batch in the grind state of the next batch of the same
formula.
« Collect pigment dust and recycle into batches.
o Reuse in batch production solvents used for cleaning sand mills, manufacturing tanks,
and tankwagons.
« Reuse obsolete materials in present production.
o Use virgin solvent for tankwagon cleaning and reuse in subsequent production.
o Pass vapors generated during filling and manufacturing through filters to remove as
much VOCs as possible; collect solvent that would otherwise have gone to atmosphere
and use as wash solvent
o Where possible, mix obsolete colors and sell as undercoat or primer.
o Accumulate all skids not usable at plant and give to skid vendor.
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e Recycle used motor oil from company vehicles.
o Reuse cardboard shipping cartons and plastic pails; return corner boards on can
shipments to supplier.
o Unrecyclable wash solvents can be used as supplemental fuel in cement kilns for
energy recovery; establish contracts with cement kilns for recycling of unusable wastes
with high BTU value.
o Inspect, repair, and reuse shipping pallets received with the purchase of raw materials
or return to vendor.
o Rinse and crush metal containers and ship to scrap metal recycler.
° Recondition and recycle drums and five-gallon pails for use.
Conclusions
The paints and coatings industry will continue to seek Dew technologies to meet the
growing needs and demands of our society. While there has been significant progress in the
industry to reduce or eliminate waste, manufacturers of all coatings recognize that new
environmental regulations may seek to significantly reduce their wastes even further. As a
result, paint manufacturers will increasingly turn to pollution prevention techniques and
methods to eliminate waste generation. Already, pollution prevention methods are making
significant contributions to reduce paint wastes/sludges through source reduction,
process/production techniques, good manufacturing practices, and material substitutions. The
coatings industry's efforts will be important towards improving environmental quality. Many
of the pollution prevention techniques developed by the paint industry are relatively simple
and inexpensive and may only require a conscious change in operating procedures. Some
changes such as new plant/equipment require greater monetary expenditures up front, but in
the long run, may provide the company with significant cost savings and improved
environmental quality.
Conclusions in this article are those of the author. No official support for these
conclusions by the U.S. EPA is intended or should be inferred.
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For Further information
There are many pollution prevention methods which have been published in various
literature or can be obtained through industry contacts. For further information, please
contact:
o Paul Randall
U.S. Environmental Protection Agency
Office of Research & Development
Risk Reduction Engineering Laboratory
26 W. Martin Luther King Drive
Cincinnati, Ohio 45268
Ph. No. 513/569-7673
FAX 513/569-7549
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APPENDIX A
REGISTRANTS
POLLUTION PREVENTION CONFERENCE ON
LOW- AND NO-VOC COATING TECHNOLOGIES
May 25 - 27, 1993 San Diego, California
Kamal Abdelmissih
Chemist
Lockheed Advanced Development
Company
1011 Lockheed Way
Palmdale, CA 93599-3731
(805)572-4351
Fax (805) 572-4315
Carl Adams
Logistics Management Specialist
U.S. Navy
Joint Depot Maintenance Analysis Group
1080 Hamilton Street
Dayton, OH 45444-5370
(513) 296-8295
Fax (513) 296-8257
Lorenzo Alejandria
Associate Air Pollution Control Engineer
San Diego Air Pollution Control
District
9150 Chesapeake Drive
San Diego, CA 92123
(619) 694-3335
Fax (619) 694-2730
Rick Almen
Chemical Tech
Coors Brewing Company
17555 West 32nd Avenue (CC290)
Golden, CO 80401
(303) 277-5024
Fax (303) 277-6670
Diane Altsman
Environmental Scientist
U.S. Environmental Protection Agency
345 Courtland Street
Atlanta, GA 30365
(404) 347-2864
Fax (404) 347-2130
Dr. Padmini de Alwis
Director
National Aquatic Resources Agency
NARA, Crow Island, Colombo 15.
Sri Lanka
09 94 522009
Fax 09 94 1 522699
Dr. C. William Anderson
Director of Research
Marine Environmental Research
P. O. Box 2013
105 North 10th Street
Morehead City, NC 28557
(919) 726-4544
Fax (919) 726-9998
William F. Anspach
Materials Engineer
Wright Laboratory/Materials
Directorate
WL/MLBT
Building 654
2941 P Street
Suite 1
Wright-Patterson AFB, OH 45433-7750
(513)255-9035
Fax (513) 255-9019
Anne Arnold
Environmental Engineer
U.S. Environmental Protection Agency
JFK Federal Building
Boston, MA 02203
(617) 565-3254
Fax (617) 565-4939 .
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Jacqueline Ayer
Manager, Engineering Operations
Acurex Environmental Corporation
Southwest Regional Offices
4883 East La Palma
Suite 505
Anaheim, CA 92807
(714) 970-5290
Fax (714) 970-5396
Brent A. Backus
Air Quality Specialist
Ventura County Air Pollution Control
District
702 County Square Drive
Ventura, CA 93003
(805)645-1428
Fax (805) 645-1444
Richard A. Benson (MS F643)
Program Manager
Los Alamos National Laboratory
P. O. Box 1663
Los Alamos, NM 87545
(505) 665-3847
Fax (505) 667-8873
Dr. Elizabeth S. Herman
Principal Paint Chemist
Naval Aviation Depot/Aimed a CA
Code 0542
Building 7
Port Hueneme, CA 94501
(510) 263-7179
Fax (510) 263-7180
Kathie J. Beverly
Environmental Engineer
Naval Aviation Depot
Code 672
Naval Air Station
North Island
San Diego, CA 92135-5112
(619) 545-4405
Fax Not Given
Julia A. Billington
Air Pollution Specialist
California Air Resources Board
2020 L Street
Sacramento, C A 95814
(916) 327-0650
Fax (916) 327-7212
Tad Bixler
Air Quality Engineer
Santa Barbara County Air Pollution
Control District
26 Castilian Drive, #B-23
Goleta, CA 93117
(805) 961-8800
Fax (805) 961-8801
Dennis Bollenbach
Group Business Manager - Coatings
SC Johnson Polymer
1525 Howe Street
Racine, WI 53403-5011
(414) 631-4751
Fax (414) 631-4079
Gene Bossie
SUPSHIP San Diego
1385 Caliente Loop
Chula Vista, CA 91910
(619) 556-3367
Fax not given
Larry Breeding
Manager, Environmental Affairs
The Walt Disney Company
500 South Buena Vista Street
Burbank, CA 91521
(818) 549-2330
Fax (818) 549-2399
Louis J. Brothers
Product Manager
Quaker Chemical Corporation
Elm and Lee Streets
Conshohcken, PA 19428
(215) 832-4223
Fax (215) 832-4497
A-2
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Angela M. Brown (MS 82-32)
Boeing Defense & Space Group
P. O. Box 3999
Seattle, WA 98124
(206) 773-2647
Fax (206) 773-4946
Larry W. Brown
Staff Engineer
Hughes Missile Systems Company
P.O. Box 11337
Building 801-18
Tucson, AZ 85734
(602) 794-7554
Fax (602) 794-7850
Richard H. Buchi
U.S. Air Force
Ogden Air Logistics Center
Science Engineering Laboratory
00-ALC/TIELM
7278 4th Street
HillAFB, UT 84056-5205
(801) 775-2992
Fax (801) 775-2628
Alan Buckley
Environmental Engineer
Massachusetts Office of Technical
Assistance
100 Cambridge Street
Room 2109
Boston, MA 02202
(612) 727-3260, Ext 662
Fax (617) 727-2754
Dan Buell
Environmental Engineer
National Steel & Shipbuilding Company
P. O. Box 85278
San Diego, CA 92186-5278
(619) 544-8764
Fax (619) 544-3542
Tom J. Burke
Manager, Paints and Coating Technology
FMC, Corporate Technology Center
1205 Coleman Avenue
Santa Clara, CA 95052
(408) 289-3820
Fax (408) 289-4429
Dr. Colin Butler
Alcan International Limited
Southam Road, Banbury
Oxon, England OX 167SP
Telephone (0295) 272626
Telex: 837601
Fax (0295) 274216
Mary-Jo Caldwell
Midwest Research Institute
401 Harrison Oaks Boulevard
Suite 350
Gary, NC 27513
(919)677-0249, Ext 5141
Fax (919) 677-0065
Michael J. Callahan
Project Engineer
Safety-Kleen Corporation
777 Big Timber Road
Elgin, IL 60123
(708) 697-8460
Fax (708) 697-4295
Gerald Ceasor
Research Associate
BP Research
4440 Warrensville Road
Cleveland, OH 44128
(216)581-5311
Fax (216) 581-5406
Carole Cenci
Permit Engineer
Minnesota Pollution Control Agency
520 Lafayette Road
StPaul, MN 55155
(612) 296-7554
Fax (612) 297-7709
A-3
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Paul Chad
Associate Engineer
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3606
Fax (619) 694-2730
David Chen, Project Engineer
Berlin Company, Ltd.
43 Ta -Yen South Road
Koahctung, Taiwan
886-7-871-1101
Fax 886-7-871-6583
Wen Yuan Chen
Project Engineer
Berlin Company, Ltd.
43 Ta -Yeh South Road
Koahctung, Taiwan
886-7-871-1101
Fax 886-7-871-6583
Frank W. Childs
Senior Program Specialist
EG & G Idaho, Inc.
P. O. Box 1625
Idaho Falls, ID 83415
(208) 526-9512
Fax (208) 526-8883
James A. Claar
Senior Research Associate
PPG Industries Research Center
P. O. Box 9
Rosanna Drive
Allison Park, PA 15101
(412) 492-5310
Fax (412) 492-5522
Robert H. Colby, Director
Chattanooga-Hamilton County
Air Pollution Control Bureau
3511 Rossville Boulevard
Chattanooga, TN 37407
(615) 867-4321
Fax (615) 867-4348
Gabriel A. Constantino
Senior Environmental Specialist II
Department of Environment & Natural
Resources, National Capital Region
100 EL-AL Building
Quezon Avenue
Quezon City, Philippines
632-96-12-89 or 632-731-7731
Fax 632-922-6991 or 632-731-7346
Kevin Contreras
Air Quality Inspector III
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 495-5515
Fax (619) 694-2730
John E. Cooper
Customer Technology Representative
Southern California Edison
403 East 4th Street
Perns, CA 92570
(909) 940-8539
Fax (909) 940-8527
E. Rick Copeland, Market Manager
Union Carbide Corporation
Unicarb Group®
3200-3300 Kanawha TPK
Building 740, Room 5126
Charleston, WV 25303
(304) 747-5296
Fax (304) 747-4886
Philip Coscia
RCI
881 Ash Avenue
Gustine, CA 95322
Phone/Fax (209) 854-6352
Laura Costello
Product Manager
Porter International
400 South 13th Street
Louisville, KY 40203
(502)588-9714
Fax (502) 588-9698
A-4
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Stan Cowen .
Air Pollution Control Engineer
Ventura County Air Pollution Control
District
702 County Square Drive
Ventura, CA 93003
(805) 645-1408
Fax (805) 645-1444
Kim Cresencia, Associate Engineer
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3990
Fax (619) 694-2730
Ella J. Darden
Technical Staff Assistant
Research Triangle Institute
3040 Comwallis Road
P. O. Box 12194
Research Triangle Park, NC 27709-2194
(919) 541-7026
Fax (919) 541-7155
Somnath Dasgupta
Waste Reduction Specialist
Iowa Waste Reduction Center
75 Biology Research Complex
Cedar Falls, IA 50613
(319) 273-2079
Fax (319) 273-2893
Paul S. Delaney
Engineering Supervisor
CTAC- SCE
6090 Irwindale
Irwindale, CA 91702
(818) 812-7549
Fax (818) 812-7381
Kevin Dick (MS 032)
Manager, Business Environmental Program
University of Nevada, Reno
Small Business Development Center
Reno, NV 89557-0100
(702) 784-1917
Fax (702) 784-4337
Erik Donhowc (MS CC284)
Environmental & Safety Services Manager
Coors Brewing Company
17755 West 32nd Avenue
Golden, CO 80401
(303) 277-3366
Fax (303) 277-6573
Peter Doty
Dow Chemical
Midland, Michigan
Small Business Development Center
MS 032
Reno, NV 89557-0100
(702)784-1917
Fax (702) 784-4337
Mark Dutcher
Sales and Market Development
Courtaulds Aerospace
409 Windjammer
Azle, TX 76020
None Given
Frank M. Ead
Materials and Processes Engineer
Lockheed Aeronautical Systems
Company
86 South Cobb Drive, #D173-B4
Marietta, GA 30062
(404)494-2818
Fax (404) 494-1610
Dr. Paul Eisele, Director
Health, Safety & Environmental Affairs
Masco Corporation
21001 Van Born
Taylor, MI 48180
(313) 374-6031
Fax (313) 374-6935
A-5
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Ensan El-ayoubi
Environmental Engineer
Missouri Department of Natural
Resources Air Pollution Control
Program
P. O. Box 176
Jefferson City, MO 65102
(314) 751-4817
Fax (314) 751-2706
David F. Ellicks
Department of the Air Force
Air Force Corrosion Program Office
WR-ALC/CNC
215 Page Road
Suite 232
Robins AFB, GA 31098-1662
(912) 926-3284
Fax (912) 926-6619
Doug Elliott
Air Pollution Compliance Specialist
State of Vermont Air Pollution Control
Division
103 South Main Street
Building 3 South
Waterbury, VT 05671-0402
(802) 244-8731
Fax (802) 241-2590
Bill Elmquist
Manager of Sales & Marketing
Technology Applications Group, Inc.
4957 10th Avenue South
Grand Forks, ND 58201
(701)746-1818
Fax (701) 746-1910
Dave Esc am ilia
Paint Manager
Aerotest, Inc.
16880 Laidlaw Street
Building 210
Mojave,CA 93501
(805) 824-9331
Fax (805) 824-2208
Caroline Espejel-Schutt
Permit Supervisor
Minnesota Pollution Control Agency
520 Lafayette Road
St. Paul, MN 55155
(612)296-7711
Fax (612) 297-7709
John C. Evans
Environmental Engineer
North Carolina - Air Quality Section
P. O. Box 29535
Raleigh, NC 27626-0535
(919) 733-3340
Fax (919) 733-5317
Al Fabiano
Industrial Engineer
U.S. Air Force
SM-ALC/LAPH
4342 Dudley Boulevard, Suite 1
McClellan AFB, CA 95652-1407
(916)643-1842
Fax (916) 643-0428
Terrel Ferreira
Stationary Source Division
Air Resources Board
P.O. Box 2815
Sacramento, CA 95812
None Given
James Folck
U.S. Air Force
Wright Patterson AFB, OH 45433-7750
None Given
Kristen Franklin (MS 032)
Pollution Prevention Technical Specialist
University of Nevada, Reno
Small Business Development Center
Reno, NY 89557-0100
(702)784-1917
Fax (702) 784-4337
A-6
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Pamela Franklin
Engineer
Acurex Environmental Corporation
555 Clyde Avenue
P. O. Box 7044
Mountain View, CA 94039
(415) 961-5700 Ext. 3399
Fax (415) 964-6523
Kevin Fulmer
Environmental Engineer I
State of Alabama
Department of Environmental
Management Air Division
1751 Cong. W. L. Dickinson Drive
Montgomery, AL 36130
(205) 271-7861
Fax (205) 271-7950
Ranji George
Program Supervisor
South Coast Air Quality Management
District
21865 East Copley Drive
Diamond Bar, CA 91765
(909) 396-3255
Fax (909) 396-3252
Mark T. Gholson
Vice President
Environment System International, Inc.
8564 Katy Freeway
Suite 132
Houston, TX 77024
(713) 984-9500
Fax (713) 984-8815
Michael Girosky (MS S302A)
Materials Engineer
Sikorsky Aircraft
Division of U.T.C.
Main Street
Stratford, CT 06601
(203)386-4708
Fax (203) 386-7523
Richard S. Goldman
Technical Manager
Concurrent Technologies Corporation
National Defense Center for
Environmental Excellence
1450 Scalp Avenue
Johnstown, PA 15904
(814) 269-2482
Fax (814) 269-2798
Marjorie Goldsmith
Quality Engineer
Aerojet Electronic Systems Division
1100 West Holly vale Street
Azusa,CA 91702
(818) 812-1787
Fax (818) 812-8077
David M. Grafflin
Evodex Powder Coatings
90 Carson Road
Birmingham, AL 35215
(205) 854-5486
Fax (205) 854-2566
Robert Grant
CA Air Resources Board
P.O. Box 2815
1100 W. Hollyvale Street
Sacramento, CA 95812
(916) 323-5774
Dr. Dan Grosse (MS 114)
Technology Development Manager
S. C. Johnson Polymer
1525 Howe Street
Racine, WI 53403-5011
(414) 631-2414
Fax (414) 631-3954
Madeline M. Grulich
Pacific Northwest Pollution Prevention
Research Center
1326 Fifth, Suite 650
Seattle, WA 98101
(206)223-1151
Fax (206) 223-1165
A-7
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Gary Gulka
Director
Vermont Agency of Natural Resources
Pollution Prevention Division
103 South Main Street
Waterbury, VT 05614-0404
(802) 244-8702
Fax (802)244-5141
Michael J. Halliwell
Material Research Engineer
U.S. Air Force
WL/MLBT
Building 653
2941 P Street
Suite 1
Wright-Patterson AFB, 45433-7750
(513) 255-3877
Fax (513) 476-4728
Steven A. Hamay
Chemist
PPG Industries, Inc.
4325 Roseanna Drive
Allison Park, PA 15101
(412) 492-5454
Fax (412) 492-5509. Oper. 492-5200
Don Hammock
Safety Manager
Varco International
P.O. Box 6626
Orange, CA 02613-6626
(714) 978-1900
Fax (714) 937-5029
Ole Jorgen Hanssen
Research Manager
Center for Applied Research
Box 276, N-1600
Fristad, Norway
4769 34 19 00
Fax 4769 34 24 94
Lisa M. Harris (TS-779)
Economist
U.S. Environmental Protection Agency
Office of Pollution Prevention &. Toxics
401 M Street, S.W.
Washington, DC 20460
(202)260-1687
Fax (202)260-0981
Scott P. Harris
Associate Hazardous Materials Specialist
California Environmental Protection
Agency
Department of Toxic Substances Control
1011 North Grand view Avenue
Glendale, CA 91201
(818)551-2831
Fax (818) 551-2874
Gary Hartnett
Air Quality Inspector II
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego. CA 92123-1095
(619) 694-3340
Fax (619) 694-2730
Henry Heck
Development Associate
Protective Coatings & Civil Engineering
DOW USA
2301 Brazosport Boulevard, #B1603
FreeporuTX 77541
(409) 238-1965
Fax (409) 238-4530
Paula Henry
• Senior Development Engineer
British Airways - N210 TEA (S429)
P. O. Box 10 - Heathrow Airport
Hounslow - Middlesex TW6 2JA U.K.
44 81 562-3104
Fax 4481 562-5403
A-8
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Dave Hodges
Environmental Scientist
U.S. Environmental Protection Agency
75 Hawthorne Street
San Francisco, CA 94610
(415)744-1197
Fax (415) 747-1076
Albert Holder (Code 2841)
Naval Surface Warfare Center
Annapolis, MD 21402-5067
(410) 267-3659
Fax (410) 267-2840
Sandra Horn
Senior Air Quality Chemist
South Coast Air Quality Management
District
21865 East Copley Drive
Diamond Bar, CA 91765-4182
(909) 396-2169
Fax (909) 396-2175
Laurence L. Hornich
Chemical Engineer
U.S. Army/Letterkenny Army Depot
Letterkenny Army Depot
Chambersburg, PA 17201-4150
(717) 267-9506
Fax (717) 267-9299
Ricke Hood
Air Pollution Control Engineer I
Pennsylvania Environmental Resources
Air Quality Control
P. O. Box 8468 - 400
Market Street - 12th Floor
Harrisburg, PA 17105-8468
(717)787-4310
Fax (717) 772-2303
Peter Hope, Technical Director
LVH Coatings/Hawking Intl Ltd. U.K.
1650 Union Avenue
Chicago Heights, IL 60411
(708) 754-0001
Fax (708) 754-0093
Paul Hoth (MS 350)
Engineer Environmental Services
Thiokol Corporation
P. O. Box 689
Brigham City, UT 84302-0689
(801) 863-8163
Fax (801) 863-5492
Glenn M. Howarth, Staff Engineer
GM Environmental and Energy Staff
30500 Mound Road, REB
P. O. Box 9055
Warren, MI 48090-9055
(313) 947-2408
Fax (313) 947-1422
Eddy W. Huang, Project Manager
The Center for Emissions Research &
Analysis
18559 East Gale Avenue
City of Industry, CA 91748
(818) 854-5868
Fax (818) 854-5869
Gene A. Huber
President
G. A. Huber Company
6407 El Pato Court
Carlsbad, CA 92009
(619) 438-1903
Fax (619) 438-4329
Martin W. Huszar
Military Sales Manager
Pro-Line Paint Company
2646 Main Street
San Diego, CA 92113
(619) 231-2813
Fax (619) 236-9681
Mark W. Ingle
Ocean City Research Corporation
1745 Jefferson Davis Highway
Suite 702
Arlington, VA 22202
(703) 212-9006
Fax (703) 212-9007
A-9
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Cindy Ivey
Environmental Coordinator
Gieiger International
7005 Fulton Industrial Boulevard
Atlanta, GA 30336
(404)344-1100
Fax (404) 346-5203
Munter T. Jabbur
Environmental Engineer
National Guard Bureau
NGB/DEV
Bldg. 3500, Stop 18
AndrewsAFB.MD 20331-6008
None Given
Kirk Jackson
Engineering Supervisor
Kyowa America Corporation
385 Clinton Street
Costa Mesa, CA 92626
(714)641-0411
Fax (714) 540-5849
Mark Jaffari
Environmental Manager
Malek, Inc.
4951 Ruffin Road
San Diego, CA 92123-1698
(619) 279-0277 (Linda Collins)
Fax (619) 279-9618
Paul Jarman
Air Quality Inspector II
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3340
Fax (619) 694-2730
David H. Johnson (MS CC284)
Senior Quality Systems Applications
Scientist
Coors Brewing Company
17755 West 32nd Avenue
Golden, CO 80401
(303) 277-5935
Fax (303) 277-6573
E. Dean Johnston
Process Engineer Senior
Hughes Aircraft Company
1901 West Malvern Avenue
Fullerton,CA 92634
(714) 732-8286
Fax (714) 732-6727
Dr. Alex Kaznoff
Naval Sea Systems Command
2531 Jefferson Davis Highway
Arlington, VA 22242-5160
(703) 602-0135
Fax (703) 602-0247
Dr. Martin W. Kendig
Member of Technical Staff
Rockwell International Science Center
1049 Camino dos Rios
Thousand Oaks, CA 91360
(805) 373-4241
Fax (805) 373-4383
Daniel N. King
Solvents and Functional Fluids Application
Support Manager
Exxon Chemical Company
5200 Bayway Drive
Baytown,TX 77522-5200
(713) 425-2462
Fax (713) 425-5890
Kevin Kinzer,
Research Specialist
3M
3M Center 201-2N-19
SL Paul, MN 55144-1000
(612) 733-6575
Fax (612) 737-2590
Doug Kirkpatrick (MS 2-3-1)
Research Scientist
SAIC
1710 Goodridge Drive
McLean, VA 22102
(703) 821-4587
Fax (703) 821-1134
A-10
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Marti Klein (Mail Code AE81)
Environmental Engineering Specialist
Rockwell International Space Systems
Division
12214 Lakewood Boulevard
Downey, CA 90241
(310)922-2116
Fax (310) 922-2844
Gig Korver
Technical Support Manager
Hexcel • Structural Products Group
5794 West Las Positas Boulevard
Pleasanton, CA 94588
(510) 847-9500, Ext. 4301
Fax (510) 734-9042
Michael Kosusko (MD 61)
Senior Project Engineer
U.S. Environmental Protection Agency
Air and Energy Engineering Research
Laboratory
Research Triangle Park, NC 27711
(919) 541-2734
Fax (919) 541-2157
Jack Kowal
Chemical Project Manager
Coors Brewing Company
17555 West 32nd Avenue
Golden, CO 80401
(303) 277-2038
Fax (303) 277-6670
Russ Krinker
Customer Technology Specialist
Southern California Edison
P. O. Box 4349
42060 10th Street, West
Lancaster, CA 93539
(805) 945-7463
Fax (805) 945-7469
John P. Kusz
Manager, Product Development
Safety-Kleen Corporation
777 Big Timber Road
Elgin, IL 60123
(708) 468-2514
Fax (708) 697-8593
Edwin Laird
Coatings Resource Corporation
15541 Commerce Lane
Huntington Beach, CA 92649
(714) 894-5252
Fax (714) 893-2322
William R. LaMarr, Program Manager
Southern California Edison Company
300 North Lone Hill
San Dimas, CA 91773
(909) 394-8859
Fax (909) 394-8922
Mark Lawless
Air Quality Inspector II
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3340
Fax (619) 694-2730
Clayton Legrand
Environmental Engineer
Naval Aviation Depot
NAS, NADEP, Box 16
Jacksonville, FL 32212-0016
(904) 772-2200
Fax (904) 772-2229
Terry D. Leland (MS 73-40)
Manager
Boeing Commercial Airplane Group
Organic Finishes and Environmental
Technology
P. O. Box 3707
Seattle, WA 98124-2207
(206) 234-3952
Fax (206) 237-0052
A-ll
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Bud Levine
Vice President
Deft Chemical Coatings
17451 Von Karman Avenue
Irvine, CA 92714
(714) 474-0400
Fax (714) 474-7269
Karen Lewis
Air Quality Inspector I
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3340
Fax (619) 694-2730
Mark E. Lindsay
Lockheed Missiles & Space Company,
Inc.
Materials & Processes Engineering
Space Systems Division
1111 Lockheed Way
Sunnyvale, CA 94989-3504
(408)742-1115
Fax (408) 742-7511
Holly K. Lippert
Hardware Engineer/Finishes
Digital Equipment Corporation
30 Forbes Road
Northboro, MA 01532
(508) 493-0491
Fax (508) 351-5018
Robert Little
Head of Materials R&D Section
Defense Research Laboratory
Building El7, Royal Arsenal East
Woolwich, London SE186TD, England
44 81-854-2044 ExL 4062
Fax 4481-854-2937
Ron Little, President
R. W. Little Coatings Company
3923 Pacific Highway
San Diego, CA 92110
(619) 297-3705
Fax (619) 692-0418
Joseph Lucas, President
Inland Technology Incorporated
2612 Pacific Highway East
Suite C
Tacoraa,WA 98424
1-800-552-3100 or (206) 922-8932
Fax (206) 926-0577
Joan Lum (EQ/E1/F157)
Senior Staff Engineer
Hughes Aircraft Company
2000 East El Segundo Boulevard
ElSegundo, CA 90245
(310) 616-1087
Fax (310) 616-0106
John Maclntyre (MS 521)
Finish Shop Manager
Dallas Manufacturing
Texas Instruments Defense
Goopd Lemroon Avenue
P. O. Box 660246
Dallas, TX 75266
(214) 956-6256
Fax Not Given
Alexander Mart
Project Manager
Southern California Edison
6070 North Irwindale Avenue, Suite I
Irwindale, California
(818) 812-7691
Fax (818) 812 7646
William Manvick
Alcan International Limited
Southaro Road, Banbury
Oxon, England OX167SP
44 295 272626
Fax 44 295 274216
David W. Maurer
Manager, Product Planning
The Gildden Paint Company
925 Euclid Avenue
Cleveland, OH 44115
(216) 344-8664
Fax (216) 344-8629
A-12
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Christopher A. Mayeux
Environmental Chemical Specialist
Louisiana Department of Environmental
Quality
11720 Airline Highway
Baton Rouge, LA 70817
(504) 295-8945
Fax (504) 295-8573
David C. McClurg
Development Representative
Miles, Inc.
Mobay Road
Pittsburgh, PA 15205-9741
(412) 777-4963
Fax (412) 777-2132
Robert C. McCrillis (MD 61)
Project Manager
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
(919) 541-2733
Fax (919) 541-2157
Jeanette McHaffey
Engineer
U.S. Air Force
SA - ALC/PIESM
450 Quentin Roosevelt Road
Kelly AFB.TX 78241-6416
(210) 925-8745
Fax (210) 925-4916
Jackie Sparrey McHugh, Administrator
Teledyne Ryan Electronics
Health, Safety & Environmental Affairs
8650 Balboa Avenue
San Diego, CA 92123
(619) 560-6400, ext 310
Fax (619) 560-1147
Beth McMinn
Environmental Engineer
TRC Environmental Corporation
100 Europa Drive, Suite 150
Chapel Hill, NC 27514
(919) 968-9900
Fax (919) 968-7557
Nick Melliadis
Eng. Physical Sciences Technician II
Colorado Department of Health/Air
Pollution Control District
4300 Cherry Creek Drive South
Denver, CO 80222
(303) 692-3175
Fax (303) 782-5493
Tony Mercer, Plant Manager
Plastic Dress-Up Company
11077 East Rush Street
South El Monte, CA 91733-9985
(818)443-7711
Fax (818) 443-1814
Wayne Paul Miller
Union Carbide Corporation
P. O. Box 8361
South Charleston, WV 25303
(304) 747-5192
Fax (304) 747-4886
Anthony A. Mitchell
President
Pro-Line Paint Company
2646 Main Street
San Diego, C A 92113
(619) 231-2813
Fax (619) 236-9681
Dan Moe
Hazardous Materials Specialist III
Sacramento County Hazardous
Materials Division
8475 Jackson Road
Suite 230
Sacramento, CA 95826
(916) 386-6170
Fax (916) 386-7040
George Mogan
Advance Systems Technology
7675 Dagget St, Suite 350
San Diego, C A 92111
(619) 974-7667
A-13
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Michael S. Moke (MZ 2852)
Consultant
Lockheed Fort Worth Company
P. O. Box 748
Fort Worth, TX 76101
(817) 777-2145
Fax (817) 777-2115
Brad Montgomery
Pollution Prevention Engineer
Lockheed Environmental Sciences and
Technologies
980 Kelly Johnson Drive
Las Vegas, NV 89119
(702) 897-3440
Fax (702) 897-6645
Mike Moran
Air Quality Inspector I
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3340
Fax (619) 694-2730
Teresa Morris
Chief, Enforcement Division
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3342
Fax (619) 694-2730
Tom Morrison, Assistant Manager
Interior Automotive Department
Red Spot Paint & Varnish Co., Inc.
P. O. Box 418
Evansville, IN 47703-0418
(812)428-9129
Fax (812) 428-9167
Brian Morton
Research Triangle Institute
P. O. Box 12194
Research Triangle Park, NC 27709
(919) 541-7094
Fax (919) 541-5945
Jeffery P. Mouser
Customer Technology Representative
Southern California Edison Energy
Services
25625 West Rye Canyon Road
Valencia, CA 91355
(805) 257-8219
Fax (805) 257-8222
Anne E. Murdoch
Environmental Protection Specialist
Naval Amphibious Base, Coronado
SCE Code 84.1, Building 16
Coronado, CA 92155
(619)437-5114
Fax (619) 437-0970
Elsa Muyco
Material & Process Engineer Senior
Teledyne Ryan Aeronautical
2701 Harbor Drive
P.O. Box 85311
San Diego. CA 92186-5311
(619)291-7311
Fax (619) 260-5400
Tom Naguy
Chemical Engineer
Wright Laboratory
WL/MLSA
2179 12th Street
Suite i
Wright-Patterson AFB, OH 45433-7718
(513)255-5117
Fax (513) 476-4419
Jim Nale
Paint Shop Chief
Municipal of Metropolitan Seattle
Metro Transit
12200 East Marginal Way South
Seattle, WA 98168-2598
(206) 684-2215
Fax (206) 684-2289
A-14
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Joven Nazareno
Air Quality Engineer
San Joaquin Valley Unified Air Pollution
Control District
1999 Tuolumne Street
Suite 200
Fresno, CA 93721
(209)497-1000
Fax (209) 233-2057
Raivo Eerik Neggo
Project Manager
Southern California Edison - Research
P. O. Box 800 601/455
Rosemead, CA 91770
(818) 302-4361
Fax (818) 302-6250
David Nelson
EnviroSearch
844 South 200 East
Salt Lake City, UT 84111
(801) 532-1717
Fax (801) 532-1777
Home (801) 649-5562
Kim K. Nguyen
Air Resources Engineer
California Air Resources Board
2020 L Street
Sacramento, CA 95814
(916)327-1513
Fax (916) 327-7212
Jonezl A. Nixon
President
CCI Inspection Services, Inc.
2203 Tiraberlock Place
Suite 231
The Woodlands, TX 77380
(713) 367-6470
Fax (713) 364-7384
Coleen M. Northeim, Manager
Research Triangle Institute
Pollution Prevention Program
3040 CornwaJlis Road
P. O. Box 12194
Research Triangle Park, NC 27709-2194
(919)541-5816
Fax (919) 541-7155
Carlos M. Nunez (MD 61)
Chemical Engineer
U.S. Environmental Protection Agency
Air and Energy Engineering Research
Laboratory
Research Triangle Park, NC 27711
(919)541-1156
Fax (919) 541-2157
Joe Oliva, Jr.,
U.S. Air Force
Facilities/Equipment Engineering Section
SA/ALC/LAPSD
Kelly AFB.TX 78241-6334
(210) 925-8541
Fax Not Given
Randy Olms
Environmental Engineer
ChemTronics, Inc.
1150 West Bradley Avenue
ElCajon, CA 92020
(619) 258-5062
Fax (619) 258-5239
Sharon Orlando (MZ K3-7160)
Senior Environmental Engineer
General Dynamics
P. O. Box 85990
San Diego, CA 92186-5990
(619) 974-3386
Fax (619) 974-4000
Ron Orrell, Staff Engineer
Martin Marietta Astronautics Group
P. O. Box 179
Denver, CO 80201
(303)971-8606
Fax (303) 971-9768
A-15
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Charles F. Outlaw
Chief of Acquisition Logistics
U.S. Air Force
ASC/EML, Building 17
2060 Third Street
Wright-Patterson AFB, OH 45433-7203
(513)255-5149
Fax (513) 255-9985
Richard Parks
Naval Sea Systems Command
Washington, DC 20362
(703) 602-0213
Susan Petersen
Senior Staff Representative
United Airlines - MOC - SFOSY
Environmental Safety Department
San Francisco International Airport
San Francisco, CA 94128
(415) 634-7209
Fax (415) 634-7385
Robert B. Pojasek, Ph.D.
GEI Consultants, Inc.
1021 Main Street
Winchester, MA 01890
(617) 721-4000
Fax (617)721-4073
Wade H. Ponder (MD 61)
Chief, Organics Control Branch
U.S. Environmental Protection Agency
Air and Energy Engineering Research
Laboratory
Research Triangle Park, NC 27711
(919) 541-2818
Fax (919) 541-2157
Donald Potenza (Code 706)
Supervisor, Electronics Technician
Naval Weapons Station
800 Seal Beach Boulevard
Seal Beach, CA 90740-5000
(310)594-7178
Fax (310) 594-71798
William J. Powell, Manager
Southern California Edison
300 North Lone Hill
San Dimas, CA 91773
(909) 394-8826
Fax (909) 394-8922
Robert Pryor
Research Biologist
TRA
2257 South 1100 East
Salt Lake City, UT 84106
(801) 485-4991
Fax (801) 485-4997
Karen Race
Industrial Safety & Environmental Control
Lockheed Aircraft Service Ontario
Department 1-533, P. O. Box 33
Ontario, CA 91761-0033
(909) 395-2804
Fax (909) 395-2080
Paul Randall
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
(513) 569-7418
Fax (513) 569-7549
Fred Raniere, Manager
Rockwell International
Material Processing & Chemistry
1049 Camino Dos Rios
Thousand Oaks, CA 91360
(805) 373-4619
Fax Not Given
Ron Reece
Environmental Engineer
Utah Division of Air Quality
1950 West North Temple
Salt Lake City, UT 84116
(801) 536-4000
Fax (801) 536-4099
A-16
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Thomas Reeves
Occupational Safety & Health Specialist
U.S. Navy - Port Hueneme
4365 Missile Way
NSWC, PHD, Code 0009
Port Hueneme, CA 93043-4807
(805) 982-8120
Fax (805) 982-6253
James Reimer
-Vice President
Plastic Flamecoat Systems, Inc.
1613 Highway 3
League City, TX 77573
(713) 332-8180
Fax (713) 554-7434
Daniel R. Rhine
Naval Aviation Depot
Code 672
Naval Air Station
North Island
San Diego, CA 92135-5112
(619) 545-4405
Fax Not Given
Nolin C. Rhodehouse
Senior Technician
Babcock & Wilcox Idaho - INEL
P. O. Box 1469
Idaho Falls, ID 83403
(208) 526-6533
Fax (208) 526-6361
William J. Riffe
Marine Environmental Research, Inc.
105 North 10th Street
P. O. Box 2013
Morehead City, NC 28557
(919) 726-4544
Fax (919) 726-9998
Don Robinson
Technical Evaluation Manager
Utah Division of Air Quality
1950 West North Temple
Salt Lake City, UT 84116
(801) 536-4000, Fax (801) 536-4099
Dr. Alexander Ross
Senior Scientist
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, DC 20460
(202) 260-2617
Fax (202) 260-4524
David Ruiz
U.S. Air Force
SM-ALC/LAPRT
3028 Peacekeeper Way
Suite 3
McClellan AFB, CA 95652-1019
(916) 643-4712
Fax Not Given
Larry F. Runyan
Director of Manufacturing Services
American Furniture Manufacturers
Association
P. O. Box HP 7
High Point, NC 27261
(919) 884-5000
Fax (919) 884-5303
Carolyn Rushforth
Project Manager
Acurex Environmental
555 Clyde Avenue
Mountain View, CA 94089
(415) 961-5700, x 3610
Fax (415) 964-6253
Peter C. Ryder
Hawking International Ltd,
Surface Coating Technology
The Stenders
Mitcheldean
Gloucestershire GL17 OZB UK
44 05 94 544325
Fax: 440594543828
A-17
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James Sainsbury, Manager
Product Regulation
The Glidden Company
925 Euclid Avenue
Cleveland, OH 44115
(216) 344-8818
Fax (216) 344-8935
Rosa Salcedo, Associate Engineer
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3324
Fax (619) 694-2730
Chuck Sales
Materials and Processes Engineer
Rohr, Inc.
P. O. Box 878
Chula Vista, CA 9192-0878
(619) 691-6718
Fax (619) 691-2148
Kenneth M. Sanders
Naval Aviation Department
Code 34200
NAS Pensacola, FL 32508-5300
(904) 452-3553
Fax (904) 452-2961
Richard Sayad
Manager
Health, Environmental & Regulatory
DOW Plastics
DOW Chemical Company
1320 Waldo Road
Midland, MI 48642
(517) 636-2867
Fax (517) 638-2446
Bruce Schwemmer
Director Regulatory Affiars
CIBA-Geigy Coporation
CIBA Additives
Seven Skyline Dirve
Hawthorne, NY 10532
(974) 785-4477
Fax (974) 347-7086
Mary Serra
Waste Management Engineer
California Department of Toxic
Substances Control
Office of Pollution Prevention and
Technology Development
301 Capitol Mall, First Floor
P. O. Box 806
Sacramento, CA 95812-0806
(916) 445-0572
Fax (916) 327-4494
Michael Sfirri
Inorganic Coatings, Inc.
500 Lapp Road
Malvern. PA 19355
1-800-345-0531 or (215) 640-2880
Fax (215) 640-1771
Uve Sillat (MS G502)
Head, Environmental Affairs
Hughes Aircraft Company
P. O. Box 92426
Building R-30
Los Angeles, CA 90009
(310) 606-2044
Fax (310) 606-2096
Mark D. Smith
Staff Materials Engineer
Allied Signal, Inc.
Kansas City Division
P. O. Box 419159
Kansas City, MO 64414-1659
(816)997-2561
Fax (816) 997-2049
Randy Smith
Air Quality Inspector III
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 495-5277
Fax (619) 694-2730
A-18
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Richard W. Sokol (SP-14J CCs)
Technical Assistant
U.S. Environmental Protection Agency
77 West Jackson Boulevard
Chicago, IL 60604
(312) 353-4347
Fax (312) 353-4342
Richard J. Sommerville
Air Pollution Control Officer
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1096
(619) 694-2730
Fax (619) 694-3303
Chris Stamos (ATD, A-5-3)
U.S. Environmental Protection Agency
Air and Toxics Division
75 Hawthorne Street
San Francisco, CA 94105
(415)744-1187
Fax (415) 744-1076
Christine Stanley
Ameron/Protective Coatings Division
210 North Berry Street
P. O. Box 1020
Brea, CA 92622-1020
(714) 529-1951
Fax (714) 990-0437
John R. Stone (9FT10)
Chemist
General Services Administration
Paints & Chemical Committee
400 15th Street, SW
Auburn, WA 98001-6599
(206)931-7929
Fax (206) 931-7039
Richard Stowe
Fusion UV Curing Systems
Fusions Systems Corporation
7600 Standish Place
Rockville, MD 20855-2798
(301) 251-0300
Fax (301) 279-0661
Charles E. Studer
Air Quality Engineer
Spokane County Air Pollution Control
Authority
West 1101 College
Spokane, WA 99201
(509) 456-4727 Ext. 107
Fax (509) 459-6828
Adeline Suson, Junior Engineer
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3214
Fax (619) 694-2730
Lucinda Swann
Air Quality Inspector II
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3340
Fax (619) 694-2730
Jim Swartz
Manager, Health & Environment
Northwest Airlines
5101 Northwest Drive, Department C1510
StPaul, MN 55111-3034
(612) 727-4841
Fax (612) 727-4845
Bruce Tabak
Supervisor Paint Finishes
Sikorsky Aircraft
North Main Street
Stratford, CT 06497
(203) 386-6728
Fax (203) 386-7185
Rodger Talbert, Technical Director
Chemical Coaters Association
International
2088 Knapp Street, NE
Grand Rapids, MI 49505
Phone/Fax (616) 365-7602
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Jack C. Taylor, VOC Unit Manager
Georgia Environmental Protection
Division/Air Protection Branch
4244 International Parkway
Atlanta, GA 30354
(404)363-7114
Fax (404) 363-7100
Dennis Thurston
Electrotechnology Specialist
Southern California Edison
1327 South Grand Avenue
Santa Ana, CA 92705
(714)458-4443
Fax (714) 458-4472
John Topalian
Technical Staff Specialist
Aerojet Electronic Systems Division
1100 West Hollyvale Street
P. O. Box 296
Azusa,CA 91702
(818) 812-1729
Fax (818) 812-8077
Larry Triplett (Mail Code 0341126)
McDonnell Douglas
P. O. Box 516
SL Louis, MO 63166
(314)232-2882
Fax (314) 233-8578
Lien Truong, Engineer Senior
Lockheed Fort Worth Company
P.O. Box 748
Fort Worth, TX 76101
(817) 777-0923
Fax (817) 777-3533
Terence D. Turner, Research Engineer
Lockheed Advanced Development
Company
P. O. Box 250
Sunland, CA 91041
(818) 847-6883
Fax (818) 847-0598
Joe Vail, Air Quality Chemist
South Coast Air Quality Management
District
21865 East Copley Drive
Diamond Bar, CA 91765
(909)396-2190
Fax (919)396-2175
Patricia Valazquez
Materials and Processes Engineer
Rohr, Inc.
P. O. Box 878
Chula Vista, CA 91912-0878
(619)691-2780
Fax (619) 691-2148
Chester A. Vogel (MD 61)
Chemical Engineer
U.S. Environmental Protection Agency
Air and Energy Engineering Research
Laboratory
Research Triangle Park, NC 27711
(919)541-2827
Fax (919)541-2157
Wilhelm Wang
Manager Product Safety
CIBA-Geigy Coporation
CIBA Additives
Seven Skyline Drive
Hawthorne, NY 10532
(974)785-4311
Fax (974) 347-7086
Jeannie Warnock
Environmental Engineer
U.S. Air Force
5146 Arnold Avenue
Suite 1
McClellan AFB, CA 95652-1077
(916)643-2190
Fax (916) 643-2193
A-20
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John Warren
Research Triangle Institute
P. O. Box 12194
Research Triangle Park, NC 27709
(919) 541-7308
Fax (919) 541-5945
Sheldon Weinstein
President
AC Products, Inc.
172 East La Jolla Street
Placentia, CA 92670
(714)630-7311
Fax (714) 777-8309
Chen Wen-Huei
Engineer-/Technical Supervisor
China Technical Consultants, Inc.
TFL, 97, Tun HWA S. RD. SEC. 2
Taipei, Taiwan (ROC)
886 2 7022831
Fax 886 2 7098825
Bob Whitfield
Safety Manager
Hearne Machining
325 West 30th Street
National City, CA 91950
(619) 474-6664
Fax (619) 474-1637
Richard Wire (MS 5T-09)
Chemical Engineer
Boeing Commercial Airplane Group
Operations Technology
P. O. Box 3707
Seattle, CA 98124-2207
(206)931-9820
Fax (206) 931-9884
Joe Yager
Senior Engineer
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3324
Fax (619) 694-2730
Laura Yannayon
Assistant Engineer
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123-1095
(619) 694-3326
Fax (619) 694-2730
Azita Yazdani
Pollution Prevention International
471 West Lambert Road
Suite 105
Brea, CA 92621
(714)255-1650
Fax (714) 255-9702
Tom Yee
Senior Vice President
Harbor Universal, Inc.
1900 Marina Boulevard
San Leandro, CA 94577
(510) 352-2100
Fax (510) 357-8704
Victor Young
Supervising Engineer
Waste Reduction Resource Center
3825 Barrett Drive
Suite 300
Raleigh, NC 27609
1-800-476-8686
Fax (919) 571-4135
Natalie Zlotin
Senior Air Pollution Control Engineer
San Diego Air Pollution Control District
9150 Chesapeake Drive
San Diego, CA 92123
(619) 694-3335
Fax (619) 694-2730
Alex Zozulin
Technology Applications Group, Inc.
4957 10th Avenue, South
Grand Forks, ND 58201
(701)746-1818
Fax (701) 746-1910
A-21
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/R-94-022
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Proceedings: Pollution Prevention Conference on Low
and No-VOC Coating Technologies
5. REPORT DATE
February 1994
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Coleen M. Northeim and Ella Darden, Compilers
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Research Triangle Institute
P. C. Box 12194
Research Triangle Park, North Carolina 27709
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
CR819541
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Proceedings: 5-10/93
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES AEERL project officer is Michael Kososko, Mail Drop 61. 919/541-
2734.
16. ABSTRACT
The report documents a conference that provided a forum for the exchange
of technical information on coating technologies. It focused on improved and emer-
ging technologies that result in fewer volatile organic compound (VOC) and toxic air
emissions than traditional coating emissions. Among the new products and improve-
ments focused on were an electrophoretic urethane coating, a zero-VOC house paint,
and developments involving such inorganic polymers as zinc silicates and silicones.
Coatings for such substrates as metal (aerospace), wood (furniture), plastic, foil,
and concrete were also discussed.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution
Coatings
Coating Processes
Emission
Organic Compounds
Volatility
Pollution Prevention
Stationary Sources
Volatile Organic Com-
pounds (VOCs)
13B
11C
13 H
14G
07C
20 M
13. DISTRIBUTION STATEMENT
Release to Public
EPA Form 2220-1 (9-73)
19. SECURITV CLASS (This Report)
Unclassified
21. NO. OF PAGES
528
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
A-22
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