Note: Descriptions are shown in the official language in which they were submitted.
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Descri~tlon
CHLORINATED ~DROCARBO~ PROTECTIVE AND~OR DECORATIV~`
- COATING Sl'RIPPING COMPOSITION AND METHOD
.
Background of the Invention
The invention is concerned with compositions which are
useful for removing or stripping protective and/or decorative
coatings from substrates. The invention is also concerned
with a method for removing said coatings.
In the manufacture of various commercial articles, it is
often the p~actice to provide such articles with a protective
and/or decorative film of a coating composition, such as a
paint film, on the surface of the article. Coating composi-
tions, such as paints, are generally construed in their normal
broad terms to include a variety of film forming compositions
which are applied in a variety of manners, such as spraying
and dipping, and include various means of applica-tion such as
with or without organic carriers, water based substances,
electrostatic sprays, application using various means of
energy for curing, such as heat, electron beam, in rared, W
and the like. In general, the paint or coating composition is
comprised of a varie_y of film forming materials, including
acrylic resins, epoxy resins, vinyl resins, polyester resins
as alkyd resins, urethanes and the like. In addition, the
substrate to which the application of the coating composition
is made generally has a corrosion protective coating applied
thereto, such as an iron phosphate coating composition of the
Bonderite type (trademark of Oxy Metal Industries Corpora-
tion).
In the course of manufacturing the articles, it becomes
desirable to remove the protective coating for a number o~
reasons, such as an inappropriate or inadequate coating, some
defect in the substrate and the like.
Use has been made in the past of chlorinated hydrocarbon
paint stripping compositions. The difficulty with many of the
previous paint stripping compositions are that they may take
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an inordinate amount of time or req~lire components that
are undesirable from the point of view of having a detri-
mental effect on the personnel who would be usin~ -the
stripping compositions.
Canadian Patent: 708,141 teaches a paint stripping com-
position which contain~ a halogenated carboxylic acid an
organic sulfonic acid in an aqueous carrier.
U.S. 3 544 365 teaches the use of methylene chloride
compositions containing triethanol amine lauryl sulfate
anionic oil soluble surfactant plus formic acid as a
composition for removing food residues.
U.S. 3 356 614 teaches a trichloroethylene composi-
tion containing an activator which is a combination of
acetic acid and trichloroacetic acid for film stripping
purposes.
The above and other compositions used in the trade
are not sufficiently efficient in removal of the coating
compositions from the substrate in a sufficient period of
time.
Summary of the Invention
The invention is concerned with a composition capable
of removing protective and/or decorative coatings from a
substrate comprising
a major amount of a chlorinated hydrocarbon of from
one to four carbon atoms;
a minor amount o a carboxylic acid accelerator use-
ful for accelerating the removal of the coating from the
substrate; and
an effecti~e amount of a penetrating amphoteric
nitrogen containing surfactant.
To improve the efficiency of the composition, a sur-
factant emulsifier of the SOX type and a corrosion in-
hibitor of the acetylenic alcohol type may be used.
Description of Preferred Embodiment
The composition of the present invention is capable of
removing a variety of films rom substrates. The substrates
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can be an~ o~ the normal substr~tes encountered ln industry,
such as iron, example steel, such as cold rolled steel or
stainless steel, or light metals, such as al-~inum, titaniuTn,
and most alloys thereof. In general, the su~strate that has
S the protective and/or decorative coating applied thereto which
is to be removed is dipped into a vat containing the coating
stripping composition of the present invention. This i5
normally performed at ambient ~emperature and pressure,
although higher temperatures up to the boiling point of the
composition could be employed. Generally no agitation is
employed, although it is to be appreciated that for increased
efficiency, agitation may be deemed desirable when a
particularly adhesive composition is to be removed from a
substrate.
In addition to the components which have been described
above, other additional components are used in the coating
composition to improve the overall efficiency. Such compo-
nents are a combination of wax and aromatic compounds which
assist in the application of the composition to the substrate
and thereby assist in the removal. The wax and aromatic
compound also retard evaporation of the stripping composition
Materials such as aromatic hydrocarbons~ as xylene, toluene,
and other alkylated aromatics may be employed. A paraffinic
wax may likewise be used.
The acetylenic alcohol that is employed in the present
case is one that inhibits corrosion of the substrate to which
the stripping CompositiGn is to be applied. Suitable acety-
lenic alcohols are hexynol, ethyloctynol, ethynyl cyclohexy-
nol, methylbutynol, methylpentynol and the like.
The acid accelerator that is useful in the present
application is a carboxylic acid that is liquid at ambient and
containing from one to twelve carbon atoms. A preferred
carboxylic acid is a halogenated carboxylic acid, such as the
chlorinated material. Suitable carboxylic acids are formic,
acetic, proprionic, butyric and the like, while the haloge-
nated acids are chloroacetic, trichloroacetic and the li~e.
It is most preferred that a combination of the acids be
~ ~ _4_
employed, such as the combination of Eormic acid and tri-
chloroacetic acid used in amounts of one part formic acid
to one to ten parts trichloroacetic acid.
~mulsifiers of the organic So~ type may be employed
such as sulfurous, sulfonic and sulfuric acids and the
like, as well as the alkali salts thereof, such as sodium,
potassium and the like. The SOX emulsifiers that are used
are generally long chain substances containing upwards of
twenty-two carbon atoms. Suitable emulsifiers of the SOX
type are petroleum sulfonate, sulfates of alcohol,
sulfates of ethoxylated alcohol, sul~ates and sulfonates
of ethoxylated alkyl phenols, sulfates of fatty esters,
sulfates and sulfonates of oils and fatty acids, sulfon-
ates of alkyl aryls, sulfonates of benzene, toluene and
xylene, sulfonates of condensed naphthalenes, sulfonates
of dodecyl and tridecyl benzene, sulfonates of naphthalene
and alkyl naphthalene and the like.
The penetratin~ amphoteric nitrogen containing sur-
factant is one that is useful for improving the efficiency
of the stripping composition. While one does not wish to
be held to any theory, it is believed that the amphoteric
nitrogen containing surfactant has a tendency to penetrate
the film to be removed, thereby allowing for destruction
and removal of the coating cornposition or film from the
substrate. Suitable amphoteric nitro~en containin~ sur-
factants are materials of the Aromox DMC-W type (trademark
of Armour Industrial Chemical Company for dimethyl coco-
amine oxide), materials such as the Miranol C2M-SF type
(trademark of Miranol Chemical Company for dicarboxylic
coconut amine derivative disodium salt), as well as the
pyridine arnphoteric type and the irnadazoline amphoteric
type. Additional usefu~ amphoteric materials are lauryl
myristyl amido propyl betaine, cocamidopropyl betaine,
cocamidopropyl hydroxy sultaine, cocobetaine, disodium
lauriminopropionate, disodium tallow-iminodipropionate,
tallow-amidopropyl hydroxy sultaine, tallow betaine. By
"amphoteric' is meant the ability to behave as an acid or
a base.
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Listed below is a recitation o~ the components of
the composition of the present invention and a preferred
range of the components:
INDE~ FOR TABLES I--IV
Ancor OW-l is a trademark of Air Products for a
material containing major amounts of hexynol.
Armohib 31 is an acid inhibitor useful in metal
cleaning and pickling which is an aliphatic amine
(trademark of Armour Industrial Chemical Company).
Petronate L is a sodium petroleum sulfonate of the
anionic type (trademark of Witco Chemical Company).
Pyronate 40 is a petroleum sulfonate (trademark of
Witco Chemical Company).
Tergitol 15-S-15 is a polyeth~lene glycol ether of
linear alkyl alcohol of the non-ionic type beiny a paste
(trademark of Union Carbide).
Sulfonic LF-7 is an alkyl polyoxyalkylene ether of
a non-ionic type having an HLB rating of 12 (HLB Index
meaning hydrophylic lipophylic balance ) (trademark of
Jefferson Chemical Company Inc.).
Plurafac D-25 is modified oxyethylated straight
chain alcohol of a non-ionic type with an HLB Index of
11 (trademark of BASF Wyandotte).
Calsoft Las-99 is linear alkyl benzene sulfonic
acid of the anionic type (trademark of Pilot Chemical
Company).
Aromox DCM-W i9 dimethyl cocoamine oxide of the
cationic type being a liquid ~trademark of Armak
Industrial Chemical of Armour Industrial Chemical
Corp~ration).
Morco M-70 which is sodium petroleum sulfonate of
the anionic type (trademark o Marathon Monco Company).
Tergitol TM~-10 is a trimethyl nonyl polyethylene
glycol ether of the non-ionic type, HLB Index of 1
(trademark of Union Carbide).
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TA3LE I ~ PROTECTIVE AND/OR ~ECO~TI~E
COATING Sl'RIPPING COMPOS[TION
Range ~Percent Preferred Prior Art
sv Wei~ht (PBW)] Ranqe (PBW) (PBW)
~ -. _ . .
Methylene Chloride at least 51 70 to ~0 83.0
Xylene 1 to 10 2 to 4 2.5
Wax .1 to 3 .5 to 1 0.5
Calsoft Las-99 1 to 10 4 to 8
Aromox DMC-W .5 to 10 1 to 5
Deionized Water 1 to 20 5 to 15
Armohib 31 5 to 5 1 1.0
Propargyl Alcohol .1 to 10 1 to 3
Petronate L 1 to 10 1 to 3 2.0
Pyronate 40 1 to 10 1 to 3
~ormic Acid 1 to 15 1 to 10 7.0
Trichloroacetic Acid 1 to 20 5 to 15
Tergitol 15-S-1~ 4.0
The composition as used by the consumer generally has a
pH of about 1.
The composition can be prepared in a number of ways.
Generally, however, the first three components are mixed
together and then the LAS-99 is blended thereto. Thereafter,
the remaining components are added in the order they are
listed in Table I.
H~ving described the invention above, listed below are
detalled aspects thereof wherein all parts are parts by weight
and temperatures are in degrees Fahrenheit unless otherwise
indicated.
Examples
In the following working examples, the compositions used
were to remove a cured acrylic resin film. The resins used
were Duracron ~00 (trademark of PPG for acrylic resin) for
examples in Table II and DuPont AP-3 acrylic resin for
examples in Tables III and IV. The reslns were applied onto
35 a test panel of steel having 3Onderite 1000 thereon (trademark
of Oxy ~etal Industries for an iron phosphate conversion
coating). The panels were dipped into the composition at
ambient to detenmine the paint removal efficiency thereof.
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TABLE II
Prior
ExamDles: A B C D E F Art
Methylene Chloride81.0 81.082.081.0 81.0 81.0 83.0
5 Xylene 2.5 2.52.5 2.5 2.52.5 2.5
Wax 0.5 0.50.5 0.5 0.50.5 0.5
Fo~r~ic Acid 7.0 7.07.0 7.0 7.07.0 7.0
Deionized Water 2.0 2.02.0 2.0 2.02.0 ---
Armohib 31 1.0 1.01.0 1.0 1.01.0 1.0
10 Petronate L 2.0
Tergitol 15-S-15 4.0
Surfonic LF-7 6.0
Pl~lrafac D-25 6.0
Calsoft Las-99 5.0
15 Aromox DMC-W 6.0
Morco M-70 6.0
Tergitol T~ l-10 6.0
Percen-t of film N.E. N.E.N.E. 100~100~6100% 109
stripped in time 20 20 20 12 28 17.5 10
20 (min-) min. min.min. min.min.min. min.
TABLE III
Examples: G H
Methylene Chloride76.0 75.5 73.5
Xylene 4.0 2.54.0
25 Wax 1.0 0.51.0
Calsoft Las-99 5.0 4.05.0
Aromox DMC-W 2.0 2.02.0
Deionized Water 2.0 2.02.0
Armohib 31 --- 1.0 ---
30 Propargyl Alcohol 1.0 --- 1.0
Petronate L --- 2.0 ---
Pyconate 40 --- 1.51.5
Formic Acid 9.0 --- 2.0
Tricholoracetic Acid --- 9.0 8.0
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35 Percent of film N.E. 100%10096
stripped in time 1010.75 6~
(min.) rr.in. min. min.
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rABLE IV
E~amples: ~ _K L
Metylene Chloride 73.5 73.0 74.5
Xylene~.0 4.0 2.5
Wax 1.0 1.0 0.5
Armohib 31~ ~ 1.0
Ancor OW~ 1.0 ---
Calsoft Las-995.0 7.0 4.0
Aromox ~C-W2.0 2.0 2.0
10 Pyconate 401.5 ___ 1.5
~eionized Water2.0 2.0 2.0
Formic Acid2.0 2.0 2.0
Trichloroacetic Acid 8.0 8.0 ~.0
Propargyl Alcohol 1.0 --- ---
15 Petronate L_-~~ ~~~ 2.0
Percent of film 100~ 100% 100%
stripped in time 6~ 4~ 9.6
(min.)min. min. min.
N.E. represents "no effect".
The test results reflect time to remove the film of acrylic
resin.
It is perfectly clear that the compositions using the
amphoteric nitrogen containing substance (Aromox type) were
clearly superior in their effeciency of removing the pro-
tective coating. Note that the prior art W2S able to removeonly 10% of the acrylic film in a ten minute period of time.
Note also that improved efficiency was obtained when the
combination of formic acid and trichloroacetic acid was used
in conjunction with the nitrogen containing amphoteric
surfactant.
It should also be noted that improved stripping
efficiency is obtained when the acetylenic alcohol corrosion
inhibitor (Ancor OW-l) is usedO
