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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to paint removers and strippers. More
specifically, it relates to a composition and method for removing paint
from a substrate. Even more specifically, it relates to a method and
composition for removing paint or the like from various substrates,
wherein the composition consists of a mixture of isopropyl alcohol and
ethylene glycol monobutyl ether.
2. Description of the Prior Art
Miniature models of various real world articles are popular pastimes both
for the satisfaction that comes from assembling them and from the display
and, in some cases, the motorized animation of the finished products.
Hobbyists can become very detail oriented in the decoration of the
objects, poring through old publications to deduce, for instance, the
exact paint scheme of various historical vehicles. One of the most popular
versions of this pastime with people of all ages is the assembly and
display of model railroads. There are various standard scales used by the
industry but in recent times the most common material used in the
manufacture of railroad models and other types of such objects is a
synthetic plastic material. This material produces durable plastic
articles which are inexpensive to manufacture and shape. One of the most
challenging aspects of the assembly process is the painting of the object.
Because of the small size of the pieces involved and the fineness of the
brushes used, mistakes can be made which, if not immediately caught, can
be difficult to correct. Paint removers that are commonly available on the
open market are not suitable in this usage because they would mar or
fatally weaken the plastic while removing the decorative paint or enamel.
Paint removers have been the subject of various patents.
In U.S. Pat. No. 1,499,101 issued on Jun. 24, 1924 to Carleton Ellis there
is disclosed a paint and varnish remover having a high flashpoint and low
degree of inflammability. The remover is basically made up of a mixture of
trichlorethylene, ethyl acetate, monochlorbenzol, and hard paraffin wax.
Another patent of interest is U.S. Pat. No. 2,705,207 issued on Mar. 29,
1955 to Ralph E. Stevens. In this patent, a two stage method for removing
paint and varnish is disclosed. In the first stage, a coating that
includes a halogen containing alkane is applied. After this has dried, a
second coating is applied that contains a normally liquid hydrocarbon, an
alcohol, an ester of an aliphatic carboxylic acid, and an alcohol whose
ester contains 3 to 5 carbon atoms, and then stripping the resulting film
from the substrate.
Next is U.S. Pat. No. 3,410,805 issued on Nov. 12, 1968 to Henry A.
Goldsmith et al. This patent described a paint stripping composition
wherein an N-substituted sulfonamide and a glycol additive are used to
improve the paint removing efficiency of an alkali metal hydroxide
solution.
The U.K. Patent specification published on Mar. 3, 1976 for Robert H.
Shoemaker et al. relates to an alkali metal hydroxide paint stripping
compositions and method.
In U.S. Pat. No. 4,973,420 issued on Nov. 27, 1990 to Micheal R. Van De
Mark there is disclosed a stripper composition for the removal of
protective coatings. The composition includes trioxane and an aromatic
hydrocarbon and an aliphatic alcohol can be added to improve the
solubility parameters.
Lastly, U.S. Pat. No. 5,049,314 issued on Sept. 17, 1991 to Sidney M. Short
discloses a paint stripping composition that consists of a five membered
ring lactone and an oxygenated aliphatic solvent.
None of the above inventions and patents, taken either singly or in
combination, is seen to describe the instant invention as claimed.
SUMMARY OF THE INVENTION
The present invention pertains to a paint stripping composition comprising
a mixture of the monobutyl ether of ethylene glycol and isopropanol and a
method of using the same. This combination of components allows for the
removal of paint from various substrates and is particularly effective in
removing paint from a plastic surface, such as those that make up scale
models without degrading or weakening the plastic.
Accordingly, it is a principal object of the invention to provide a
stripping composition that allows the user to easily and safely remove the
paint from various surfaces.
It is another object of the invention to provide a stripping composition
that allows the paint to be stripped from a plastic substrate without
marring or structurally weakening the plastic being treated.
It is a further object of the invention to provide a stripping composition
where the residue of paint and the stripper itself can be easily rinsed
off with water.
These and other objects of the present invention will become more readily
apparent upon further review of the following detailed description.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a composition consisting essentially of a
mixture of the monobutyl ether of ethylene glycol and isopropyl alcohol.
The present mixture contains about 30% to 70% by weight of ethylene glycol
monobutyl ether and about 70% to 30% by weight of isopropyl alcohol. The
preferred ratio of ethylene glycol monobutyl ether to isopropanol for use
on a painted plastic substrate is 60% to 40%. This mixture allows for
efficient stripping of paint from a plastic substrate. The preferred
mixture of the monobutyl ether of ethylene glycol and isopropyl alcohol
provides for a somewhat viscous liquid. This allows for either immersion
of the piece in question or a brush or spray application. It should be
noted that though plastic is discussed as the principal substrate in this
specification, this composition will remove paint from other various
substrates such as metal in the same manner as herein described.
Various tests of the compositions of the present invention have been
conducted, and the results are reported below. Herein all ratios of
components are set forth as percentages by weight unless stated otherwise.
In the preferred mixture of approximately 60% ethylene glycol monobutyl
ether and 40% isopropyl alcohol, a piece of plastic of the standard type
found in modeling kits was painted with an enamel paint and was allowed to
dry. The painted plastic piece was then completely immersed in the mixture
and was allowed to remain submerged in the composition for five minutes.
When the piece was taken from the present liquid composition, the paint
could be readily removed from the plastic substrate by a light rubbing
motion with a cloth or by hand, and was easily and completely removed from
the piece by rinsing in running water. No structural degradation or
weakening of the plastic substrate was noted and the molded surface
details of the stripped plastic piece were not blurred or distorted in any
way.
When a composition containing 50% ethylene glycol monobutyl ether and 50%
isopropanol was tested in the same manner over the same time period,
weakening of the plastic substrate was observed and the piece was
noticeably more flexible than before immersion.
In another test, a mixture having a proportion of 30% ethylene glycol
monobutyl ether to 70% isopropyl alcohol was employed. While there was no
substrate degradation noted in this particular test, the immersion time
had to be extended to one hour before the paint could be removed.
Reversing the previous proportion of the mixture to 70% ethylene glycol
monobutyl ether and 30% isopropanol, substrate degradation was apparent
and the immersion time needed for removal of the paint was 16 minutes.
In another test, 12 plastic models were obtained. The first was covered
with a coat of spray enamel. The second was covered with two coats of
spray enamel and so on, so that the twelfth model has 12 coats of the
enamel applied to it. All the models were completely dry. At this point
all twelve of the models were completely immersed in the 60% ethylene
glycol monobutyl ether and 40% isopropyl alcohol mixture for a five minute
period. Afterwards, the paint was easily and completely removed from all
of the models.
It has been noticed additionally that a mild temperature elevation, such as
would be obtained by immersing a pan containing the stripper composition
in a hot tap water bath, accelerates the removal of the paint.
As mentioned above, the composition is soluble in water, which makes the
actual removal of the paint from the substrate simple. If a mistake is
made during application of the stripper composition, quickly rinsing the
piece, or the portion of the piece affected, in running water will prevent
the stripper from acting on the area. If deep crevasses or the like were
to be encountered in the workpiece, a small brush, similar to a
toothbrush, could be used to remove paint therefrom.
It should be emphasized that though synthetic plastics make up the
substrates discussed above, the stripper herein described will work
equally well on metal, ceramic, stone, or similar materials. Suitable
synthetic plastics include polystyrene, methacrylates, or polyethylene,
for example, that can be used to produce durable finished articles.
Additionally, applicant has tested various dilutions of the mixture and has
found that a 50% dilution, for example, works very well as a cleaner for
engine parts or similar items. Even weaker dilutions, it has been noted,
can act as a cleaner for other various soiled surfaces.
It is to be understood that the present invention is not limited to the
sole embodiment described above, but encompasses any and all embodiments
within the scope of the following claims.
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