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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a chemical composition. More particularly, this
invention relates to a solution for use in a vapor generating apparatus.
Even more particularly, this invention relates to a chemical composition
which is a mixture of a cleaning or drying solution and a solubilized or
suspended coating compound. 2. Description of the Prior Art
In the present state of the art, vapor generating and recovering
apparatuses are used for cleaning or drying of objects, such as metallic
tools, plastic parts, and the like. In a finishing application (cleaning
or drying) of these objects, a solvent is heated to boiling and the object
to be finished is immersed therein. The solvents used are usually
chlorinated organic compounds having two or less carbon atoms.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a unique chemical composition
for cleaning or drying and coating objects. It is another object of this
invention to provide a chemical solution for use at its boiling
temperature in a vapor generating apparatus. It is even another object of
this invention to provide an improved chemical composition for use in a
vapor generating apparatus for adding a selected coating to an object
during cleaning or drying. Other objects and advantages of this invention
will become apparent upon reading the accompanying disclosure.
The present invention resides in the discovery that a solution for cleaning
or drying objects may include a selected coating therein to enhance
resistance to erosion, corrosion, friction, and the like. In a vapor
cleaning or drying process the selected coating must be compatible with
the cleaning or drying solution and also be capable of withstanding the
boiling temperature of the cleaning solution without changing its chemical
and physical properties. Particularly, coating compounds useful in the
present invention include those compounds which dissolve in a selected
cleaning or drying solution and have vaporizing temperatures greater than
those of the selected cleaning compound. Some examples of coating
compounds useful in this invention include, for example, dimethyl
silicones, organo-silicone compounds, as well as fluorocarbons which are
well known in the art for protecting articles from corrosion, erosion,
friction, and the like. These include low molecular weight dimethyl
silicones which are liquid linear, branched or cyclic dimethyl silicones,
from the dimer through the octamer, of which the linear tetramer is
preferred. Organosilicones suitable as solutes are liquid linear
polyoxyalkylated dimethyl silicones of the formula:
(CH.sub.3).sub.3 SiO(CH.sub.3).sub.2 SiO.sub.m Si(CH.sub.3).sub.2
(CH.sub.2).sub.n O(C.sub.2 H.sub.4 O).sub.x CH.sub.3
wherein m is an integer from 2 to 6, n is an integer from 1 to 3 and x is a
number from 1 to 18, for example:
(CH.sub.3).sub.3 SiO(CH.sub.3).sub.2 SIO.sub.6 Si(CH.sub.3).sub.2
(CH.sub.2).sub.3 O(C.sub.2 H.sub.4 O).sub.11 CH.sub.3
Fluorosilicones suitable as solutes include the fluorosilicones containing
the repeating unit,
CH.sub.3
--SiO--
CH.sub.2 CH.sub.2 CF.sub.3
Suitable volatile liquid perfluoroalkanes and fully fluorinated bromo- and
chloroalkanes for the liquid compositions of the invention are, for
example, perfluoropentane, perfluorohexane, trichlorofluoromethane,
dibromodifluoromethane, tribromofluoromethane,
1,1,2-trichloro-1,2,2-trifluoroethane,
1,2-dibromo-1,1,2,2-tetrafluoroethane,
1,1,2-trichloro-2,2,3,3,3-pentafluoropropane,
1,1,1,3-tetrachloro-2,2,3,3-tetrafluoropropane and
2,2,3-trichloro-1,1,1,3,4,4,4-heptafluorobutane mixtures thereof, and
1,1,2,2-tetrachloro-1,2-difluoroethane. One preferred flourinated
hydrocarbon useful in the present invention is tetrafluoroethylene. Also
silicon containing oil compounds, and beeswax have also been found useful
in the present invention. Vegetable oils, such as soybean oil, peanut oil,
corn oil, sunflower oil, palm oil, linseed oil, and the like as well as
fish oil or animal oils, petrolatums, such as mineral oil, paraffin, and
the like may also be used. However, these coating compounds are merely
exemplary and are not intended to be unduly limitative of the present
invention.
The cleaning and drying compounds which have been found compatible with the
coating compounds include the non-polar solvents, such as the halogenated
organic compounds with two or less carbon atoms. These include, for
example, trifluoromethane, trichloromonofluoromethane,
trichlorotrifluoroethane, methylene chloride, methyl chloroform,
perchloroethylene, and the like. These non-polar solvents may be mixed
with or used in the absence of water.
The composition within the scope of this invention for cleaning or drying
comprises a solution containing from about 0.1 to 10 percent by weight of
the coating compound in a solution containing at least one organic
compound having two or less carbon atoms. In a preferred embodiment from
about 2 to 5 percent by weight of the coating compound is used in a
solution containing at least one halogenated organic compound. And
preferably, cleaning or drying and coating is carried out at the boiling
temperature of the composition mixture. In some applications compatible
surface active agents may be used.
According to the present invention, objects to be cleaned or dried and
protected from corrosion, erosion, friction, and the like are immersed in,
preferably, a boiling solution of a composition including the coating
compound and an organic compound having two or less carbon atoms. The time
of the immersion is usually relatively short, generally being accomplished
within about 1 minute. Upon removal from the boiling solution, the solvent
vaporizes off leaving the coating on the object which has been cleaned or
dried. Furthermore, spraying or other means for subjecting the object to
be treated in the boiling solution may also be used without departing from
the scope and spirit of this invention.
Since the coating compound is compatible with organic compounds and water,
mixing of the compounds does not require any special technique.
A more comprehensive understanding of the invention can be obtained by
considering the following examples. However, it should be understood that
the examples are not intended to be unduly limitative of the invention.
EXAMPLE I
The following example demonstrates one procedure that is followed in
preparing and using a composition of the present invention for treating
engine parts.
A solution is prepared by adding 10 parts by weight of a mineral oil to 90
parts by weight of trichlorotrifluoroethane in a vapor generating
apparatus. The solution is brought to boiling wherein engine parts are
immersed therein for about 30 seconds.
The engine parts immersed in the solution are cleaned and coated uniformily
with the oil upon removal from the boiling solution.
EXAMPLE II
The following example demonstrates one procedure that is followed in
treating a mold for plastic parts with a composition of the present
invention.
A solution is prepared by adding 2 parts by weight of tetrafluoroethylene
to 98 parts by weight of trichlorotrifluoroethane in a vapor generating
apparatus. The solution is brought to boiling wherein a mold for plastic
parts is immersed therein for removal of water (drying), the immersion
time being about 30 seconds.
The mold immersed in the solution will be clean upon removal from the
boiling solution and coated uniformly with the tetrafluoroethylene.
EXAMPLE III
The following example demonstrates one procedure that is followed in
preparing and using a composition of the present invention for treating a
blood filter to prevent the foaming of blood during filtration.
A solution is prepared by adding 30 parts by weight of a silicon oil to 70
parts by weight of trichloromonofluoromethane in a vapor generating
apparatus. The solution is brought to boiling wherein blood filters are
immersed therein for about 11/2 minutes.
The filters immersed in the solution will be free of foreign materials upon
removal from the boiling solution and uniformly coated with a silicon
protective coating.
EXAMPLE IV
The following example demonstrates one procedure that is followed in
preparing and using a composition of the present invention for treating a
ceramic circuit board.
A solution is prepared by adding 88.5 parts by weight of
trichlorotrifluoroethane, 10 parts by weight of N-methyl pyrrollidone, 1
part by weight of beeswax and 0.5 parts by weight of water in a vapor
generating apparatus. The solution is brought to boiling wherein a ceramic
circuit board is immersed therein for about 30 seconds.
The ceramic circuit board immersed in the solution will be clean upon
removal from the boiling solution and uniformly coated with a protective
coating of beeswax.
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