United States
                    Environmental Protection
                    Agency
Water Engineering Research
Laboratory
Cincinnati OH 45268
                    Research and Development
EPA/600/S2-86/063 Sept. 1986
&ERA         Project  Summary
                    Evaluation  of  Alternatives  to
                    Toxic  Organic Paint  Strippers
                    Wilfred J. Hahn and P. O. Werschulz
                      A study was undertaken to survey
                    commercially available paint stripping
                    formulations and identify those whose
                    use would result in lower total toxic or-
                    ganics (TTO) loading in stripping opera-
                    tion wastewaters without decreasing
                    the effectiveness or efficiency of the
                    stripping  operation. Data were gath-
                    ered by means of a  literature review, a
                    survey of potential suppliers, and
                    bench scale tests of alternative strip-
                    ping formulations identified as having
                    potential for reducing the level of re-
                    leased TTO. The chemical composition
                    of an epoxy stripper (MS-111)* used ex-
                    tensively in military installations was
                    compared with commercially available
                    alternatives having the potential to re-
                    duce TTO in  stripping wastewaters.
                    The paint stripping operation at the
                    Sacramento Army Depot (SAAD) was
                    studied to establish a basis for design-
                    ing bench scale tests that would com-
                    pare the performance characteristics.
                      The bench scale tests of SAAD-
                    supplied samples and the selected al-
                    ternative formulations identified three
                    stripping  formulations that met the
                    performance standards experienced by
                    MS-111 and that were expected to sig-
                    nificantly reduce TTO levels in stripping
                    operation wastewaters.
                      This Project Summary was devel-
                    oped by EPA's Water Engineering Re-
                    search Laboratory,  Cincinnati, OH, to
                    announce key findings of the research
                    project that is fully documented in  a
                    separate report of the same  title (see
                    Project Report ordering information at
                    back).
                    •Mention of trade names or commercial products
                    does not constitute endorsement or recommenda-
                    tion ior use.
Introduction

Background
  This study was undertaken to identify
commercially available paint strippers
that would reduce TTO (as defined in 40
CFR Part 413) levels in stripping opera-
tion wastewaters. A review of industry
literature identified alternatives that had
potential for reducing TTO. Bench scale
tests were performed to identify each
alternative's performance characteris-
tics and potential for reducing TTO in
stripping operation wastewaters.

Total Toxic Organics in
Stripping Operations
Wastewaters
  Contributors to TTO enter stripping
operation wastewaters principally
through "dragout," a term applied to
material that adheres to metal parts as
they are removed from the  stripping
tank. This material is deposited in the
rinse water or removed in the hot water/
steam lancing operation and is dis-
charged to the floor drain system. Two
substances present in  most  stripping
formulations contribute to TTO levels:
methylene chloride and phenol.


SAAD Paint Stripping
Operation
  SAAD  refurbishes communication
and other electronic equipment and the
enclosures used to house the  equip-
ment. The majority of the equipment
encountered at SAAD is fabricated from
aluminum, and exposure to hot caustic
liquid would cause severe corrosion.
Accordingly, cold, acidic,  organic,
solvent-based stripping formulations
are used. The primary formulation used

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at SAAD is MS-111, the trade name of
an epoxy stripper produced by Miller-
Stephenson Chemical Company, Inc.
The formulation  contains (by volume)
85% methylene chloride, 10% phenol,
5% formic acid, and less than 1% surfac-
tant. The substance of greatest concern
is methylene chloride, a major contribu-
tor to the TTO found in stripping opera-
tion wastewaters. Of lesser concern is
phenol, which also contributes to TTO
but in far smaller amounts.
  Materials to  be stripped are loaded
into a large wire  mesh basket and low-
ered into the cold strip (MS-111) tank for
approximately 20 minutes. The  exact
submergence time in the stripper  is left
to the operator's judgement, since strip-
ping efficiency is often affected by the
shape of the pieces and the way they
are  packed in the basket. After a  short
drainage period, the basket  is dipped
briefly into a hot (170°F) caustic solution
to neutralize the acidity of the stripping
solution. After draning the caustic solu-
tion, the basket is submerged in a water
rinse tank. Finally, the parts are individ-
ually cleaned with  a high pressure
steam/hot water  lance.

Methods

Identification  of Alternative
Paint Strippers
  Materials safety data sheets (MSDS)
or other literature describing the chemi-
cal  composition  of stripping products
was solicited from 68 potential suppli-
ers. A review of this information yielded
a listing of formulations judged to have
the potential to  meet performance re-
quirements  and  reduce TTO levels in
stripping operation  wastewaters pri-
marily because these formulations con-
tained  less methylene chloride than did
the MS-111. The chemical composition
of the  formulations selected for  study
are presented in  Table 1.

Bench Scale Test Program
  The bench scale test program was de-
signed to simulate operation conditions
at SAAD and to provide performance
data on alternative stripping formula-
tions for comparison with MS-111. Test
procedures were  prepared to obtain
data on the efficiency of removal  of the
paint finishes typically encountered in
the SAAD refurbishing operation. Per-
sonnel conducting the  tests were in-
structed to note any abnormal precau-
tions  required in  the handling of
strippers, to record weight loss data on
the coupons tested, and to provide de-
Table 1.   Chemical Composition of Candidate Strippers
Supplier
Nalco Chemical Co.
GAP
Enthone, Inc.
Savogran Co.
Savogran Co.
Trade Name
84TB-227
140641
S-26
Stripeeze
Kutzit
Composition*
Chemical
Cyclic amide
N-methyl-2-pyrrolidone
Methylene chloride
Phenol
Formic acid
Methylene chloride
Toluene
Methanol
Acetone
Paraffin wax
Methylene chloride
Methanol
Toluene
Acetone
Paraffin wax
Percent
100
100
<50
<20
<5
<20
<40
<30
<25
<2
<30
<30
<30
<30
<2
Mitchell-Bradford
Chemical Company

Miller-Stephenson
Chemical Company
Oakite Products
Oakite Products
Quick Strip-8


MS-111




ALM (Ambient)




FHS
Methylene chloride
An acid

Methylene chloride
Phenol
Formic acid
Surfactant

Monoethyl amine
Furfuryl alcohol
Tributyl phosphate
Sodium hydroxide

Butyl cellosolve
Formic acid
Mixed Aromatics
Diisobutyl ketone
Dodecylbemene sulfonic
  acid
Hydrofluoric acid
Oakite Products

Enthone, Inc.
ALM (180°)

S-26 Diluted 1:1 With Water
60
85
10
 5
 10
 10
<5
35
 15
 10
 10
                                                                       <5
*From materials safety data sheets or updated information from suppliers.
tailed comments on the results of a
visual inspection following the stripping
and stream lansing operations.

Results

Test Evaluation Procedures
  Performance  of each candidate for-
mulation  was  evaluated  against  re-
quirements of SAAD for surface prepa-
ration before applying new coatings
and was compared with the perform-
ance of MS-111 on similar paint sam-
ples specifically prepared for the bench
scale tests. Only stripping formulations
demonstrating the capability to remove
all types of SAAD-provided paint sam-
                ples were considered viable alternatives
                to MS-111.

                Summary Comparison of
                Alternative Formulations
                 Comparisons were based primarily
                on  visual examination of the sample
                coupons in accordance with  stripping
                operation  evaluation procedures at
                SAAD; however,  physical data were
                also analyzed. Before and after the strip-
                ping operation, each paint sample cou-
                pon was weighed and its thickness was
                measured. Although these data did not
                provide a precise measurement of strip-
                ping efficiency, they did tend to support

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the conclusion reached through visual
inspection. Stripping efficiency for all of
the formulations tested is summarized
in Table 2.
Overall Evaluation and Ranking
of Alternative Strippers
Viable alternatives to MS-1 1 1 must be
available commercially and must have
demonstrated the capability of remov-
ing all types of paint encountered in re-
furbishing equipment at the SAAD. Can-
didate strippers satisfying these criteria
must next be judged on their potential
for eliminating or reducing the TTO in
the stripping operation wastewaters.
Based on the concentration of
methylene chloride and phenol, as re-
ported in the MSDS or provided by the
supplier, the three acceptable alterna-
tives are ranked as follows:
• Enthone S-26 diluted 1 : 1 with water—
60% reduction in TTO expected;
• Mitchell-Bradford Quick Strip No. 8—
33% reduction in TTO expected and
• Enthone S-26 (undiluted)— 22% re-
duction in TTO expected.

Table 2. Effectiveness of Commercial Paint Strippers
Percent of Top Coat Removed After 20-Minute Submergence
Paint Type


Paint Stripper
MS-111 MC*

MC 100
S-26 MC
/Hi/ 1
\Lfli. /
QS No. 8 MC

ALM (Hot)*

FHS

GAF 140641*
Nalco 84TB227
Stripeeze MC

Kutzit MC
ALM**


Enamel
on Zinc
100

100
100

100

100

100

100
100
100

100
100
Enamel
on Zinc
Chro-
mate
100

100
100

100

100

100

100
100
100

100
100
Enamel
on Zinc
Chro-
mate
100

100
100

99

100

100

50
20
75

50
25

Epoxy
on
Primer
100

100
100

3

0

0

0
0
0

0
0
Poly-
amide
on
Epoxy
100

100
100

100

100

50

0
0
0

0
0
Poly-
amide
on
Water
Reduce
100

100
100

100

100

95

0
0
0

0
0
Poly-
amide
on Zinc
Chro-
mate
100

100
100

100

100

20

0
0
0

0
0
Poly-
amide
on
Epoxy
100


100

100

100

0

0
0
0

0
0
 'Contains methylene chloride.
 +Stripper heated to 82°C (180°F) as recommended by supplier.
 #Pure chemical compound; no commercial formulations available. Also recommended to be
  used hot, although not known  prior to the test.
**Same formulation as "X" tested at room temperature.

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      Wilfred J. Hahn and P. P. Werschulzare with Carltech Associates, Inc. Columbia,
        MD2W45.
      Thomas J. Powers is the EPA Project Officer (see below).
      The complete report, entitled "Evaluation of Alternatives to Toxic Organic Paint
        Strippers," (Order No. PB86-219 177/AS; Cost: $16.95, subject to change) will
        be available only from:
             National Technical Information Service
             5285 Port Royal Road
             Springfield, VA22161
             Telephone: 703-487-4650
      The EPA Project Officer can be contacted at:
             Water Engineering Research Laboratory
             U.S. Environmental Protection Agency
             Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
- - „  L. ,3. C (~ i- X" - ">. •- F-A#v«J
Official Business
Penalty for Private Use $300

EPA/600/S2-86/063
           0000329    PS

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