VAPOR PHASE SILOXANE DRY CLEANING PROCESS
TECHNICAL FIELD
The present invention is directed to a dry cleaning process, more
specifically, to a siloxane vapor phase based process, for use in dry cleaning.
BACKGROUND
Current dry cleaning technology uses perchloroethylene ("PERC) or
petroleum-based materials as die cleaning solvent. PERC suffers from
toxicity and odor issues. The petroleum-based products are not as effective as
PERC in cleaning garments.
Cyclic siloxanes have been reported as spot cleaning solutions/ see US
4,685,930/ and as dry cleaning fluids in dry dearungm^hineS/ see US
5,942,007. Other patents disclose the use of silkone soaps in petroleum
solvents, see JP 09299687, and the use of silkone surfactants in super critical
carbon dioxide solutions has been reported, see, for example, US 5,676,705
and Chem. Mark. Rep., 15 Dec 1997,252(24), p. 15. Non-volatile silicone oils
have also been used as the cleaning solvent requiring removal by a second
washing with perfluoroalkane to remove the silicone oil, see JP 06327888.
Numerous other patents have issued in which siloxanes or
organomodified silkones have been present as addenda in PERC or
petroleum based dry cleaning solvents, see, for example, WO 9401510; US
4911853; US 4005231; US 4065258.
There is a continued interest in decreasing the need for large quantities
of solvents used in dry cleaning processes.
SUMMARY OF THE INVENTION
The process of the present invention is directed to a cleaning process,
comprising the use of a volatile cyclic, linear or branched siloxane in the
vapor phase for the cleaning of articles.
Further, the present invention provides for a process for cleaning soiled__
articles of manufacture comprising:
a) contacting the soiled article of manufacture with a vapor phase silicone
compound;
b) allowing the vapor phase silicone compound in contact with the soiled
article of manufacture to condense to the liquid phase becoming thereby a
condensed silicone liquid; and
c) draining the condensed silicone liquid away from the article of
manufacture whereby the soiled article of manufacture is cleaned.
In another embodiment the present invention provides for a process for
cleaning soiled garments comprising:
a) contacting the soiled garment with a vapor phase silicone compound;
b) allowing the vapor phase silicone compound in contact with the soiled
garment to condense to the liquid phase becoming thereby a condensed
silicone liquid; and
c) draining the condensed silicone liquid away from the garment whereby
the soiled garment is cleaned.
DETAILED DESCRIPTION OF THE INVENTION
The compounds useful in the practice of the present invention may be
linear, branched or cyclic volatile siloxane compounds. In general those
siloxanes that are volatile and suitable for use in the practice of the present
invention are those siloxanes that are volatile at room temperature, i.e. about
25 °G Volatility is a quantitative measurement at a given temperature and
thus broadly defined involves a partial pressure or vapor pressure, i.e. a
pressure below 760 mm Hg, at a given temperature. Broadly, volatile
siloxanes are those siloxanes that have a vapor pressure or partial pressure
(as used herein the two terms are interchangeable) above 0.01 mm Hg at a
temperature ot 20 °C
Compounds suitable as the linear or branched, volatile siloxane
solvent of the present invention are those containing a polysiloxane structure
that includes from 2 to 20 silicon atoms. Preferably, the linear or branched,
volatile siloxanes are relatively volatile materials, having, for example, a
boiling of below about 3O0°C point at a pressure of 760 millimeters of
mercury ("mm Hg").
In one embodiment, the linear or branched, volatile siloxane comprises
one or more compounds of the structural formula (I):
M2*y2*DxTyQz (I)
wherein:
M is IPaSiOi/a;
DisRWSiOz/z
T is R4SiO3/2;
and Q is SiO4/2
R1, R2, R3 and R4 are each independently a monovalent hydrocarbon radical
having from one to forty carbon atOms; and
x and y are each integers, wherein 0 £ x ^ 10 and 0 £ y £ 10 and 0 £ z 510.
Suitable monovalent hydrocarbon groups include linear hydrocarbon
radicals, branched hydrocarbon radicals, monovalent alicyclic hydrocarbon
radicals, monovalent and aromatic or fluoro containing hydrocarbon radicals.
Preferred monovalent hydrocarbon radicals are monovalent alkyl radicals,
monovalent aryl radicals and monovalent aralkyl radicals.
As used herein, the term "(Q-QJalkyr means a linear or branched
alkyl group containing from 1 to 6 carbons per group, such as, for example,
methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl,
pentyl, hexyl, preferably methyl.
As used herein, the term "aryl" means a monovalent unsaturated
hydrocarbon ring system containing one or more aromatic or fluoro
containing rings per group, which may optionally be substituted on the one
or more aromatic or fluoro containing rings, preferably with one or more (Ci-
C6)alkyl groups and which, in the case of two or more rings, may be fused
rings, including, for example, phenyl, 2,4,6-trimemylphenyl, 2-
isopropylmethylphenyl, l-pentalenyl, naphthyl, anthryl, preferably phenyl.
As used herein, the term "aralkyl" means an aryl derivative of an alkyl
group, preferably a (C2-C6)alkyl group, wherein the alkyl portion of the aryl
derivative may, optionally, be interrupted by an oxygen atom, such as, for
example, phenylethyl, phenylpropyl, 2-(l-naphthyl)ethyl, preferably
phenylpropyl, phenyoxypropyl, biplKnytoxypropyl.
In another embodiment, the monovalent hydrocarbon radical is a
monovalent (Ci-QJalkyl radical, most preferably, methyl.
In another embodiment, the linear or branched, volatile siloxane
comprises one or more of, hexamethyldisiloxane, octamethyltrisiloxane,
decamethyltetrasiloxane, dodecamethylpentasiloxane,
tetradecamethylhexasiloxane or hexadecamethylheptasiloxane or
methyltris(trimethylsiloxy)s0ane. In a more highly preferred embodiment,
the linear or branched, volatile siloxane of the present invention comprises
octamethyltrisiloxane, decamethyltetrasiloxane, or
dodecamethylpentasiloxane or memyltris(trimemylsiloxy)silane. In a highly
preferred embodiment, the siloxane component of the composition of the
present invention consists essentially of decamethyltetrasiloxane.
Suitable linear or branched volatile siloxanes are made by known
methods, such as, for example, hydrolysis and condensation of one or more of
tetrachlorosilane, methyltrichlorosilane, dimethyldichlorosilane,
trimethylchlorosilane, or by isolation ol the desired fraction of an equilibrate
mixture of hexamethyldisiloxane and octamethylcyclotetrasiloxane or the like
and are commercially available.
Compounds suitable as the cyclic siloxane component of the present
invention are those containing an oligomeric or polysiloxane ring structure
that includes from 2 to 20 silicon atoms in the ring. Preferably, the linear,
branched and cyclic siloxanes are relatively volatile materials, having, for
example, a boiling point of below about 300°C at a pressure of 760 millimeters
of mercury ("mm Hg"). Thus for the purposes of defining a volatile siloxane
compound useful in the practice of the process of the present invention a
volatile siloxane, whether linear branched or cyclic has a vapor pressure
ranging from O.OlJo 760 mm Hg; at a temperature ranging from about 10 °C
to about 300 °C
In another embodiment, the cyclic siloxane comprises one or more
compounds of the structural formula (II):
wherein:
R5, R6, R7 and R* are each independently a monovalent hydrocarbon group
having from one to forty carbon atoms; and
a and b are each integers wherein 0 £ a £ 10 and 0 < b ^ 10, provided that 3 <
(a + b)<10.
In yet another embodiment, the cyclic siloxane comprises one or more
of, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane,
dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane. In a
more highly preferred embodiment, the cyclic siloxane of the present
invention comprises octamethylcyclotetrasiloxane or
decamethylcyclopentasiloxane. In yet another embodiment, the cyclic
siloxane component of the composition of the present invention consists
essentially of decamethylcyclopentasiloxane.
Suitable cyclic siloxanes are made by known methods, such as, for
example, hydrolysis and condensation of alkylhalosilanes, e.g.
dimethyldichlorosilane, and are commercially available.
The process of the invention involves generation of a gas phase silicone
by a combination of heating the silicone in a solvent reservoir and optionally
reducing pressure so as to allow the silicone to vaporize followed by
contacting the silicone vapors with the garment to be cleaned. While the
formula describing compounds useful in the process of the present invention
has already been described, those compounds useful in the practice of the
present invention in one embodiment should have vapor pressures between
about 3.0 mm Hg and about 760 mm Hg at temperatures ranging from about
20 °C to about 100 °C. In a second embodiment those compounds useful in
the practice of the present invention should have vapor pressures between
about 0.01 mm Hg and about 760 mm Hg at temperatures ranging from
about 20 °C to about 270 °C In a third embodiment those compounds
useful in the practice of the present invention should have vapor pressures
. between about 1.0 mm Hg and about 760 mm Hg at temperatures ranging
from about 20 °C to about 134 °C In a fourth embodiment those
compounds useful in the practice of the present invention should have vapor
pressures between about 0.01 mm Hg and about^60jTun Hg at temperatures
ranging from about 20 °C to about 264 °C
Alternatively, other methods known in the art can be employed to
form vapors of silicones including mechanical means.
The vapors of the compounds of the present invention thus formed,
either at atmospheric pressure or at reduced pressure, are allowed to contact
the fabric to be cleaned for a specified time wherein these same vapors
condense in the fabric, dissolving the soiling material or stain and draining
away from the fabric, after which time the articles are removed, cooled as
needed, and dried by various methods known in the art such as air drying,
heated drying and the like. In one embodiment, the process of the present
invention may be performed at a constant pressure. In another embodiment
the process of the present invention is performed at a pressure that is varied
among the steps of the process, e.g. initially contacting the garment to be
cleaned with a vapor at a pressure below atmospheric followed by raising the
pressure to atmospheric pressure to condense the vapor in the garment and
allow the cleaning fluids to drain away from the garment
Alternatively, the articles remain in the cleaning vessel and the silicone
or silicone containing solvent is removed by various means and the articles
are dried in the cleaning vessel as is commonly seen in typical dry cleaning
machines.
An article, such as for example/ a textile or leather article, typically, a
garment, is cleaned by contacting the article with the vapors of the
composition of the present invention. In a preferred embodiment the articles
to be cleaned include textiles made from natural fibers, such as for example,
cotton, wool, linen and hemp, from synthetic fibers, such as, for example,
polyester fibers, polyamide fibers, polypropylene fibers and elastomeric
fibers, from blends of natural and synthetic fibers, from natural or synthetic
leather or natural or synthetic fur.
The article and dry cleaning composition are then separated, by, for
example, one or more of draining and centrifugation. In a preferred
embodiment, separation of the article and dry cleaning composition is
followed by the application of heat, preferably, heating to a temperature of
from 15°C to 120°C, preferably from 20*C to 100°C, or reduced pressure,
preferably, a pressure of from 1 mm Hg to 750 mm Hg, or by application of
both heat and reduced pressure, to the article.
Testing for oil soluble stain removal was accomplished using a blue
5iV^^o^poly ^othj»nd .ajrsLsitin. fatafe, The approximately 2 inch
square samples were stained with motor oil, suspended by wires in a large
glass vessel equipped with a thermometer/ and condensing unit capable of
condensing the volatile silicone solvent. The articles were positioned such that
the solvent vapors saturated the article but were not contacted by the
returning, condensed solvent.
The process of the present invention is not limited to the cleaning of
garments or articles of clothing, it may be applied to any article of
manufacture contaminated with a silicone soluble contaminant that may be
subjected to the process of the present invention wherein the contaminant is
dissolved in the silicone compound and drained away, thereby removing the
contaminant from the article of manufacture.
The following examples are to illustrate the invention and are not to be
construed as limiting the claims.
EXAMPLES
Example 1 - Atmospheric pressure, cyclic solvent
Samples of red satin and blue cotton/ poly fabrics were treated with
motor oil which was allowed to stain for 18 hours then attached to a wire
holder and suspended above a reservoir of D5. The solvent was heated to
boiling and the vapors allowed to contact the stained fabrics for 5 minutes.
After this time, the heat was removed, the vessel cooled and the samples
removed and air dried and evaluated. All traces of the oil were removed from
both fabrics. There was some extraction of the red dye from the satin fabric.
Example 2 - Reduced Pressure, cyclic solvent
Samples of red satin and blue cotton/poly fabrics were treated with
motor oil which was allowed to stain for 18 hours then attached to a wire
holder and suspended above a reservoir of D5. The pressure in the system
was reduced to 1-2 nun Hg and the temperature of the solvent reservoir was
raised to 70-80 °C The vapors were allowed to contact the stained fabrics for 5
minutes. After this time, the heat was removed, the vessel cooled and the
samples removed and air dried and evaluated. All traces of the oil were
removed from both fabrics. No extraction of the red dye from the satin fabric
was observed.
Example 3 - Reduced Pressure, linear solvent
Samples of red satin and blue cotton/ poly fabrics were treated with
motor oil which was allowed to stain for 18 hours then attached to a wire
holder and suspended above a reservoir of MD2M. The pressure in the
system was reduced to 1-2 mm Hg and the temperature of tine solvent
reservoir was raised to 70-80 °C The vapors were allowed to contact the
stained febrics for 5 minutes. After mis time, the heat was removed, the vessel
cooled and the samples removed and air dried and evaluated. All traces of the
oil were removed from both fabrics. No extraction of the red dye from the
satin fabric was observed.
Having described the invention, that which is claimed is:
1. A process for cleaning soiled garments comprising:
a) contacting the soiled garment with a vapor phase silicone compound;
b) allowing the vapor phase silicone compound in contact with the soiled
garment to condense to the liquid phase becoming thereby a
condensed silicone liquid; and
c) draining the condensed silicone liquid away from the garment
whereby the soiled garment is cleaned.

2. The processas claimed in claim 1 wherein the silicone compound has the formula:
M2+y+2zDxTyQi
wherein:
MisRisSiCh/s
D is R2R3SiQ2/2;
TisR^SiOj/a;
and Q is SiO4/2
R1, R2, R3 and R4 are each independently a monovalent hydrocarbon radical
having from one to forty carbon atoms; and x and y are each integers,
whereinO£x£lOandO£y£10and(J£z£lO.

3. The processas claimed in 1 wherein the silicone compound has the formula:
wherein:
R5, R6, R7 and R* are each independently a monovalent hydrocarbon group
having from one to forty carbon atoms; and
a and b are each integers wherein 0 5 a £ 10 and 0 < b < 10, provided that 3 <
(a + b)<10.
as claimed in
4. The proces^&f claim 2 wherein each of the steps a), b) and c) are
independently conducted at a temperature ranging from about 10 °C to abotrt
300°C

5. The process as claimed in claim 3 wherein each of the steps a), b) and c) are
independently conducted at a temperature ranging from-about 10 °C to«bevtt
300 °C.

6. The processas claimed in claim 4 wherein each of the steps a), b) and c) are
independently conducted at a pressure ranging from*feettfc0.01 mm Hg __
about 760 mm Hg.

7. The processas claimed in claim 5 wherein each of the steps a), b) and c) are
independently conducted at a pressure ranging from afo4&¥ 0.01 mm Hg to
about 760 mm Hg.

8. The process as claimed in claim 6 wherein the silicone compound is selected from
the group consisting of hexamethyldisiloxane, octamethyltrisiloxane,
decamethyltetrasiloxane, dodecamethylpentasiloxane,
tetradecamethylhexasiloxane, hexadecamethylheptasiloxane and
methyltris{trimethylsi]oxy)silane.

9. The proces as claimed in claim 7 wherein the silicone compound is selected from
the group consisting of hexamethyldisiloxane, octamethyltrisiloxane,
decamethyltetrasiloxane, dodecamethylpentasiloxane,
tetradecamethylhexasiloxane, hexadecamethylheptasiloxane and
methyltris(trirnethylsiloxy)silane.
10. A process for cleaning soiled articles of manufacture comprising:
a) contacting the soiled article of manufacture with a vapor phase silicone
compound;
b) allowing the vapor phase silicone compound in contact with the soiled
article of manufacture to condense to the liquid phase becoming
thereby a condensed silicone liquid; and
c) draining the condensed silicone liquid away from the article of
manufacture whereby the soiled article of manufacture is cleaned.
11. A process for cleaning soiled garments consisting essentially of:
a) contacting the soiled garment with a vapor phase silicone compound;
b) allowing the vapor phase silicone compound in contact with the soiled
garment to condense to the liquid phase becoming thereby a
condensed silicone liquid; and
c) draining the condensed silicone liquid away from the garment
whereby the soiled garment is cleaned.

12. The process/of claim 11 wherein the silicone compound has the
formula:
Mafy+2zDxTyQt
wherein:
MisR^iOi/a;
D is R2R3SiO2/a;
TisR«iQ3/2;
and Q is SiO«/2
R1, R2, R3 and R4 are each independently a monovalent hydrocarbon radical
having from one to forty carbon atOms; and x and y are each integers,
wherein0£x<10and0£y£l0and0£z<10.
as yclaimed in
13. The process/of claim 11 wherein the silicone compound has the
formula:
wnerein:
R5, R*, R7 and R* are each independently a monovalent hydrocarbon group
having from one to forty carbon atoms; and
a and b are each integers wherein 0 < a £ 10 and 0 < b £ 10, provided that 3 £
(a + b)£!0.

14. The proces as claimed in 60 claim 12 wherein each of the steps a), b) and c) are
independently conducted at a temperature ranging from abevt 10 °C to abort
300 °C

15. The process as claimed in claim 13 wherein each of the steps a), b) and c) are
independently conducted at a temperature ranging from about 10 °C to-afeoOf
300 °C

16. The process as claimed in claim 14 wherein each of the steps a), b) and c) are

independently conducted at a pressure ranging from admit 0.01 mm Hg to
-abcnrt760mmHg.

17. The process as claimed in claim 15 wherein each of the steps a), b) and c) are
independently conducted at a pressure ranging from-abewt 0.01 mm Hg to
-afeeet 760 mm Hg.

18. The process as claimed in claim 16 wherein the silicone compound is selected
from the group consisting of hexamethyldisiloxane, octamethyltrisiloxane,
decamethyltetrasiloxane, dodecametfiylpentasiloxane,
tetradecamethylhexasiloxane, hexadecamethylheptasiloxane and
methy]tris(trimethylsiloxy)silane.

19. The proces as claimed in claim 17 wherein the silicone compound is selected
from the group consisting of hexamethyldisiloxane, octamethyltrisiloxane,
decamethyltetrasiloxane, dodecamethylpentasiloxane,
tetradecamethylhexasiloxane, hexadecamethylheptasiloxane and
methyltris(trimethylsiloxy)silane.

The process of the present invention is directed to a dry cleaning process,
comprising the use of volatile cyclic, linear or branched siloxanes in the vapor
phase for the cleaning of soiled or stained fabrics. The linear or branched
siloxanes have the formula: M2+y+2zDxTyOZ wherein M is R13SiO1/2; D is
R2R3SiO2/2; T is R4SiO3/2; and Q is SiO4/2; R1,R2 and R4 are each independently a
monovaient hydrocarbon radical having form one to forthly carbon stems; and x
and y are each integers, wherein 0 < x <10 and 0 < y < 10 and 0 < z < 10.
While the cyclic sibxanes have the formula (1) wherein R5, R6, R7 and R8 are
each independently a monovaient hydrocarbon group having from one to forty
carbon atoms; and a and b are each integers wherein 0 < a < 10 and 0 < b <
10, provided that 3 < (a+b) < 10.