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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