Method of making organo-silicon polymers having mono- and tetra-functional siloxane units

There is disclosed a method for making organo-silicon polymers from alkyldisiloxanes and alkylsilicates wherein the alkyl groups of the disiloxanes have two or more carbons. Gelling of the organo-silicon polymers is avoided by; first mixing the disiloxane with the alkylsilicate and adding thereto a strong protic acid; and, after reaction has occurred in the aforementioned mixture, adding thereto, in a drop-wise manner, a solution of hydrochloric acid.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to a method of making 
organo-silicon polymers and more specifically to a method of making such 
polymers having both mono- and tetra-functional siloxane units. 
2. Description of the Prior Art 
Organo-silicon polymers having both mono- and tetra-functional siloxane 
units are well known in the art. In the past, such polymers have generally 
been prepared by cohydrolysis of a hydrolyzable silane or disiloxane 
(which are used as the feed material for mono-functional siloxane units) 
and a silicate salt or an alkyl silicate (which are used as the feed 
material of the tetra-functional siloxane units.) 
When a disiloxane is used as the feed material for the mono-functional 
siloxane units, the average molecular weight can be controlled, so that 
the organo-silicon polymer which forms can have a relatively narrow 
distribution of the average molecular weight. 
In Japanese Kokai Patent Application No. Sho 61[1986]-195129 there is 
proposed such a method wherein tetraethoxysilane or another alkyl silicate 
is added drop-wise to a mixture of hexamethyldisiloxane or other 
alkyldisiloxane, concentrated hydrochloric acid, water and ethanol. The 
drawback of the method, however, is that when a disiloxane having C.sub.2 
or higher monovalent hydrocarbon radicals is used as the feed material, 
the products formed therein have a tendency to gel during reaction. The 
gel so-formed is resistant to dissolution, even with the addition of more 
solvent. 
In accordance with the method of the present invention, the tendency of the 
reaction products to gel during formation has been overcome, even when a 
mixture of disiloxane having C.sub.2 or higher monovalent hydrocarbon 
radical and alkyl silicate is used as the feed material in making the 
aforementioned organo-silicon polymer. 
SUMMARY OF THE INVENTION 
In accordance with the present invention there is provided a method for 
making an organo-silicon polymer of the general formula: 
EQU (Me.sub.2 RSiO.sub.1/2).sub.m (SiO.sub.4/2).sub.n 
wherein: 
Me is a methyl radical; 
R is a substituted or unsubstituted monovalent hydrocarbon radical having 
two or more carbon atoms; and 
the ratio of m/n is between 0.2 and 4; 
the method comprising the steps of: 
mixing components 
(A) a disiloxane of the general formula (Me.sub.2 RSiO).sub.2 (wherein Me 
and R are as defined above) and 
(B) an alkyl silicate; 
said components (A) and (B) being present in a molar ratio of substantially 
1/2 m/n; 
adding between 0.005 parts and 50 parts by weight of a strong protic acid 
to 100 parts by weight of the above mixture of components (A) and (B) and 
allowing the same to react; and 
adding an aqueous solution of hydrochloric acid to the above reaction 
mixture in a drop-wise manner. 
As used herein in connection with the description of component (B), the 
term "alkyl silicate" is meant to include partial hydrolysis products of 
alkyl silicates. 
Also as used herein to describe the addition of certain reactants or 
catalysts, the term "drop-wise" means that the reactant or catalyst is 
being added at a relatively slow rate. In the case of an experiment being 
carried out on a laboratory scale, such additions are made at a rate that 
is literally drop-wise. Those skilled in the art, however, will recognize 
that for the same reaction being carried out on a manufacturing or pilot 
plant scale, the use of the term "drop-wise" will not mean that the 
addition is literally being made drop-wise, but that the rate of addition 
is relatively slow.

DETAILED DESCRIPTION OF THE INVENTION 
In accordance with the method of the invention, a mixture of a disiloxane 
and an alkyl silicate is first made. A strong protic acid is then added to 
the mixture and reaction is allowed to proceed. Thereafter, an aqueous 
solution of hydrochloric acid is added to the reaction mixture in a 
drop-wise manner, which results in the production of the organo-silicon 
polymer. 
The disiloxanes used in the method of the invention are represented by the 
general formula (Me.sub.2 RSiO).sub.2, wherein R represents a substituted 
or unsubstituted monovalent hydrocarbon radical, such as: an ethyl 
radical, propyl radical, butyl radical, or other alkyl radical; a 
cyclohexyl radical, or other cycloalkyl radical; a vinyl radical, allyl 
radical, hexenyl radical, or other alkenyl radical; a phenyl radical, 
xylyl radical, or other aryl radical; a phenylethyl radical, or other 
aralkyl radical; or 3-chloropropyl radical, 3,3,3-trifluoropropyl radical, 
etc. The various types of disiloxanes may be used either alone or in 
combination. 
Examples of alkyl silicates (which by definition include partial hydrolysis 
products thereof) used in the method of the invention include orthomethyl 
silicate, polymethyl silicate, orthoethyl silicate, polyethyl silicate, 
orthopropyl silicate and polypropyl silicate. 
Strong protic acid catalysts suitable for practicing the method of the 
invention include sulfuric acid, trifluoromethanesulfonic acid, 
chlorosulfonic acid, trichloroacetic acid, trifluoracetic acid, 
p-toluenesulfonic acid, phosphoric acid, nitric acid, etc. 
In the first stage of the method of the invention, a strong protic acid is 
added to a mixture of the disiloxane, component (A), and the alkyl 
silicate, component (B), for reaction therewith. The mixing ratio of 
component (A) to the component (B) should be selected such that the ratio 
of the mono-functional siloxane units to the tetra-functional siloxane 
units of the organo-silicon polymer (i.e. m/n) represented by the general 
formula (Me.sub.2 RSiO.sub.1/2).sub.m (SiO.sub.4/2).sub.n is between 
0.2-4. 
The amount of the strong protic acid catalyst added to 100 parts by weight 
of the sum of components (A) and (B) should be 0.005-50 parts by weight, 
or preferably 0.015-10 parts by weight. 
The first stage of the method of the invention is preferably carried out at 
a temperature between about 0.degree. C. and 180.degree. C., and more 
preferably between room temperature and 100.degree. C. The reaction time 
may depend on the reaction temperature, and is usually 30 minutes to 3 
days. 
More specifically, the reaction time for the first stage is determined by 
tracing the decrease in the amount of disiloxane, component (A), using 
chromatography or other analysis means. In the first stage, a portion of 
component (A) is decomposed to silane represented by the formula 
SiOR'(CH.sub.3).sub.2 R (wherein R has the same meaning as above and R' 
represents the alkyl radical in component (B)), and the other portion is 
taken up into alkyl silicate in units of (CH.sub.3).sub.2 RSiO. 
In carrying out the first stage of the method of the invention, an organic 
solvent not directly related to the reaction may be added as a diluent to 
the mixture of components (A) and (B). Examples of such organic solvents 
include benzene, toluene, xylene and other aromatic hydrocarbons; hexane, 
heptane, and other alkanes; diethyl ether, tetrahydrofuran, and other 
ethers; acetone, methyl isobutyl ketone, and other ketones; 
1,1,2-trichlorotrifluoroethane, 1,1,1,-trichloroethane, dichloromethane, 
.alpha.,.alpha.,.alpha.-trifluorotoluene, hexafluoroxylene, and other 
halogenated hydrocarbons; methanol, ethanol, isopropanol and other 
alcohols; etc. 
In accordance with the method of the invention, a second reaction results 
when hydrochloric acid solution is added drop-wise to the aforementioned 
reaction mixture. It is preferred that an aqueous hydrochloric acid 
solution containing over 5 wt % of hydrogen chloride, or more preferably 
over 10 wt % hydrogen chloride, be used. The amount of the aqueous 
hydrochloric acid solution should be enough to ensure that the amount of 
water contained in the hydrochloric acid solution is enough to perform 
hydrolysis for all of the alkoxy radicals present after the strong protic 
acid has been added to the mixture of components (A) and (B). However, it 
is also acceptable to use more aqueous hydrochloric acid solution. The 
temperature during the drop-wise addition should be 0.degree.-100.degree. 
C. It is nevertheless convenient to use the temperature set for the first 
stage of operation continuously. 
After the end of the first stage of the method of the invention and before 
drop-wise addition of aqueous hydrochloric acid solution in the second 
stage of the invention, it is acceptable to add hydrolyzable alkyl silane 
represented by the formula R".sub.3 SiX (where R" represents a monovalent 
hydrocarbon radical, X represents halogen atom or alkoxy radical, etc.) as 
the feed material of mono-functional siloxane units. 
As described above, it is possible to manufacture organo-silicon polymers 
represented by the general formula 
EQU (Me.sub.2 RSiO.sub.1/2).sub.m (SiO.sub.4/2).sub.n 
where Me, R, m and n have the same meanings as above. 
After the method of the invention is used to make the aforementioned 
organo-silicon polymer, the organic layer is isolated from the water 
layer; the organic layer is neutralized and washed with water; dehydration 
is carried out in an azeotropic process with the organic solvent. If 
needed, the organic solvent is removed, and the desired organo-silicon 
polymer is isolated. 
The following examples illustrate the method of the invention in greater 
detail. In the examples, Me represents a methyl radical, and Et represents 
an ethyl radical. 
APPLICATION EXAMPLE 1 
11.9 g (0.04 mol) of component (A) represented by the formula (CH.sub.2 
.dbd.CHC.sub.4 H.sub.8 Me.sub.2 Si).sub.2 O, 41.6 g (0.2 mol) of 
tetraethoxysilane, 20 g of toluene, and 0.03 g of trifluoromethanesulfonic 
acid were added to a flask, and reaction was performed at 65.degree. C. 
for 5 hours while the mixture was stirred. 
As the reaction mixture was analyzed using gas chromatography, it was found 
that almost all of component (A) disappeared. Then at 60.degree. C., a 
mixture of 10.1 g of water and 6.8 g of 36% aqueous hydrochloric acid 
solution was added drop-wise over 30 minutes. After the end of the 
drop-wise addition, stirring was continued at 72.degree. C. for 6 hours. 
Then the reaction mixture was cooled and 50 g of toluene were added. The 
organic layer was isolated from the water layer, and was washed with water 
to neutrality. It was then moved to a flask with a water isolating tube 
attached, where dehydration was performed at reflux temperature. After 
cooling, the solvent was removed, and 14.3 g of light-yellowish 
transparent oil-like substance were obtained. 
The analytical results of the oil-like substance are as follows. 
SiNMR .delta.(ppm): 13(0.33Si, br, CH.sub.2 .dbd.CHC.sub.4 H.sub.8 Me.sub.2 
SiO.sub.1/2); Si-100(0.19Si, br, ROSiO.sub.3/2); -110(0.48Si, br, 
SiO.sub.4/2); (R is CH.sub.3 CH.sub.3 CH.sub.2 or H.). 
.sup.13 CNMR .delta.(ppm): 139(1.00C, s, .dbd.CH--); 115(0.94C, s, CH.sub.2 
.dbd.); 59(1.54C, s, --OCH.sub.2 CH.sub.3); 34(1.00C, s, 
Si(CH.sub.2).sub.3 CH.sub.2 --); 33(1.06C, s, Si(CH.sub.2).sub.2 CH.sub.2 
--); 23(0.90C, s, SiCH.sub.2 CH.sub.2 --); 18(2.56C, s, SiCH.sub.2 -- or 
--OCH.sub.2 CH.sub.3); 0(1.12C, s, SiCH.sub.3). 
GPC (gel permeation chromatography): Mw: weight-average molecular 
weight=1.5.times.10.sup.4 ; Mn: number-average molecular 
weight=4.1.times.10.sup.3. 
It was determined that the obtained hexenyl radical-containing silicone 
resin is an organo-silicon polymer with residual hydroxy radicals and 
ethoxy radicals on its terminals and having a chemical configuration 
represented by the average unit formula: 
EQU (CH.sub.2 .dbd.CHC.sub.4 H.sub.8 Me.sub.2 SiO.sub.1/2).sub.0.49 
(SiO.sub.4/2).sub.1.0 
APPLICATION EXAMPLE 2 
14.3 g of toluene were added to 14.3 g of the resin product of Application 
Example 1, followed by addition of 3.2 g (0.02 mol) of (Me.sub.3 Si).sub.2 
NH, and then heating with reflux for 6 hours. After cooling, the reaction 
mixture was washed once by 50 g of water, neutralized by an aqeuous 
hydrochloric acid solution, and then washed with water repeatedly. Then a 
water isolating tube was used to heat the sample with reflux for 
dehydration, and solvent was further distilled off, forming 15.1 g of 
light-yellowish oil-like substance. 
The analytical results of the oil-like substance are as follows. 
.sup.29 SiNMR .delta. (ppm): 13(0.41Si, br, R'Me.sub.2 SiO.sub.1/2); 
-100(0.11Si, br, ROSiO.sub.3/2); -110(0.48Si, br, SiO.sub.4/2); (R 
represents CH.sub.3 CH.sub.2 or H, R' represents CH.sub.2 
.dbd.CH(CH.sub.2)CH.sub.4 or Me). 
.sup.13 CNMR .delta. (ppm): 139(1.00C, s, .dbd.CH--); 115(1.00C, s, 
CH.sub.2 .dbd.); 59(0.25C, s, --OCH.sub.2 CH.sub.3); 34(1.06C, s, 
Si(CH.sub.2).sub.3 CH.sub.2 --); 33(1.06C, s, Si(CH.sub.2).sub.2 CH.sub.2 
--); 23(0.94C, s, SiCH.sub.2 CH.sub.2 --); 18(1.28C, s, SiCH.sub.2 -- or 
--OCH.sub.2 CH.sub.3); 0(3.56C, s, SiCH.sub.3). 
GPC (gel permeation chromatography): Mw: weight-average molecular 
weight=8.2.times.10.sup.4 ; Mn: number-average molecular 
weight=4.0.times.10.sup.3. 
It was determined that the obtained hexenyl radical-containing silicone 
resin is an organo-silicon polymer with residual hydroxy radicals and 
ethoxy radicals on its terminals and having a chemical configuration 
represented by the average unit formula: 
EQU (Me.sub.3 SiO.sub.1/2).sub.0.22 (SiO.sub.4/2).sub.1.0 (CH.sub.2 
.dbd.CHC.sub.4 H.sub.8 Me.sub.2 SiO.sub.1/2).sub.0.48 
COMATIVE EXAMPLE 1 
The method described in Japanese Kokai Patent Application No. Sho 
61[1986]-195129 was adopted in a test to synthesize an organo-silicon 
polymer represented by the formula (CH.sub.2 .dbd.CHC.sub.4 H.sub.8 
Me.sub.2 SiO.sub.0.5).sub.0.45 (SiO.sub.2).sub.1 in the following process: 
6.71 g (0.0225 mol) of disiloxane represented by the formula (CH.sub.2 
.dbd.CHC.sub.4 H.sub.8 Me.sub.2 Si).sub.2 0, 4 g of toluene, 2 g of 
ethanol, 2 g of acetone, and 8 g of 12N hydrochloric acid were mixed by 
stirring and heating at 76.degree. C., while 20.8 g (0.1 mol) of ethyl 
silicate were added drop-wise. However, midway through the drop-wise 
addition of ethyl silicate, a gel-like substance was generated. The 
gel-like substance could not be dissolved even after adding an organic 
solvent. 
APPLICATION EXAMPLE 3 
6.52 g (0.02 mol) of disiloxane represented by the formula (CF.sub.3 
CH.sub.2 CH.sub.2 Me.sub.2 Si).sub.2 0 20.8 g (0.1 mol) of 
tetraethoxysilane, 12.0 g of .alpha.,.alpha.,.alpha.-trifluorotoluene as 
the organic solvent and 0.02 g of trifluoromethanesulfonic acid were added 
to a flask, and reaction was performed at 65.degree. C. for 5 hours while 
the mixture was stirred. 
Then at 65.degree. C., a mixture of 10.1 g of water and 6.8 g of 36% 
aqueous hydrochloric acid solution were added drop-wise over 30 minutes. 
After the end of the drop-wise addition, stirring was continued at 
77.degree. C. for 30 minutes. Then the reaction mixture was cooled and the 
organic layer was isolated from the water layer, and was washed with water 
to neutrality. It was then moved to a flask with a water isolating tube 
attached, where dehydration was performed at reflux temperature. After 
cooling, the solvent was removed, and 13.9 g of white solid substance at 
room temperature were obtained. 
The white solid substance obtained was soluble in tetrahydrofuran, acetone, 
methyl isobutyl ketone, .alpha.,.alpha., .alpha.-trifluorotoluene, and 
other organic solvents. The analytical results of the white solid 
substance are as follows. 
.sup.29 SiNMR .delta.(ppm): 13(0.30Si, br, CF.sub.3 CH.sub.2 CH.sub.2 
Me.sub.2 Si.sub.1/2); -100(0.25Si, br, ROSiO.sub.3/2); -110(0.45Si, br, 
SiO.sub.4/2); (R is CH.sub.3 CH.sub.2 or H.). 
.sup.13 CNMR .delta.(ppm): 128(3.81C, q, --CF.sub.3); 59(0.91C, s, 
--OCH.sub.2 CH.sub.3); 28(4.20C, s, --SiCH.sub.2 CH.sub.2 CF.sub.3); 
18(1.00C, s, --OCH.sub.2 CH.sub.3); 10(4.06C, s, SiCH.sub.2 --); 0(8.16C, 
s, S, SiCH.sub.3). 
GPC (gel permeation chromatography): Mw: weight-average molecular 
weight=8.0.times.10.sup.3 ; Mn: number-average molecular 
weight=6.2.times.10.sup.3. 
It was determined that the obtained trifluoropropyl radical-containing 
silicone resin is an organo-silicon polymer with residual hydroxy radicals 
and ethoxy radicals on its terminals and having a chemical configuration 
represented by the average unit formula: (CF.sub.3 C.sub.2 H.sub.4 
Me.sub.2 SiO.sub.1/2).sub.0.43 (SiO.sub.4/2).sub.1.0 
COMATIVE EXAMPLE 2 
The method disclosed in Japanese Kokai Patent Application No. Sho 
61[1986]-195129 was used. 18.6 g (0.1 mol) of disiloxane represented by 
the formula (CH.sub.2 .dbd.CHMe.sub.2 Si).sub.2 O, 30 g of toluene, 6 g of 
acetone, 6 g of ethanol, 12 g of concentrated hydrochloric acid and 17 g 
of water were mixed. While the mixture was stirred at 70.degree. C., 83.3 
g (0.4 mol) of ethyl silicate were added drop-wise. After cooling, 100 ml 
of toluene were added. After isolation from the water layer, the organic 
layer was washed with water to neutrality, and dehydration was carried out 
by azeotropic process with toluene. Then 11.3 g of hexamethyldisilazane 
were added, followed by heating with reflux for 6 hours in toluene 
solvent. The organic layer was then washed with water to neutrality, and 
dehydration was performed with azeotropic process with toluene to further 
remove the low-boiling-point components, forming the organo-silicon 
polymer. This organo-silicon polymer was in solid form at room 
temperature. The organo-silicon polymer was dissolved in toluene with a 
concentration of 10 wt %. It was found that when the solution was filtered 
under a reduced pressure using No. 5A filter paper, clogging occurred, and 
the filtering property was poor. 
APPLICATION EXAMPLE 4 
18.6 g (0.1 mol) of disiloxane represented by the formula (CH.sub.2 
.dbd.CHMe.sub.2 Si).sub.2 O, 83.3 g (0.4 mol) of tetraethoxysilane, 40 g 
of toluene and 4 g of 98% sulfuric acid were blended and heated at 
80.degree. C. for 6 hours. Then a mixture of 12 g of 12N hydrochloric acid 
and 20 g of water was added drop-wise. After the end of the drop-wise 
addition, stirring was continued at 76.degree. C. for 4 hours. 
Then the reaction mixture was cooled and 50 g of toluene were added. After 
the organic layer was isolated from the water layer, it was washed with 
water to neutrality. It was then moved to a flask with a water isolating 
tube attached, where dehydration was performed at reflux temperature. Then 
toluene was removed until the solids content became 50 wt %. After 
cooling, 11.3 g of hexamethyldisilazane were added, followed by 6 hours of 
heating with reflux. After cooling, the organic layer was washed with 
water to neutrality, and dehydration was performed with an azeotropic 
process with toluene to further remove the organic solvent, forming 
organo-silicon polymer. NMR analysis of the organo-silicon polymer 
indicated that it has a chemical configuration represented by the formula 
(CH.sub.2 .dbd.CHMe.sub.2 SiO).sub.0.5 (Me.sub.3 SiO.sub.0.5).sub.0.1 
(SiO.sub.2).sub.1.0, and is in solid form at room temperature. 
The organo-silicon polymer was dissolved in toluene to form a solution with 
a concentration of 10 wt %. When it was filtered using a No. 5A filter 
paper under a reduced pressure, excellent filtration property was 
displayed, and there was no problem. 
APPLICATION EXAMPLE 5 
45.0 g (0.15 mol) of disiloxane represented by formula (CH.sub.2 
.dbd.CHC.sub.4 H.sub.8 SiMe.sub.2).sub.2 O, 624.9 g (3.00 mol) of 
tetraethoxysilane, 360.0 g of toluene, and 240 .mu.L of 
trifluoromethanesulfonic acid were added to a flask, and reaction was 
performed at 65.degree. C. for 5 hours while the mixture was stirred. As 
the reaction mixture was analyzed using gas chromatography, it was found 
that almost all of the disiloxane represented by the formula (CH.sub.2 
.dbd.CHC.sub.4 H.sub.8 Me.sub.2 Si).sub.2 O disappeared. After cooling, 
141.6 g (1.20 mol) of trimethylethoxysilane were added, followed by 
heating and stirring. Then at 60.degree. C., a mixture of 151.2 g of water 
and 102.0 g of 36% aqueous hydrochloric acid solution was added drop-wise 
in 30 min. After the end of the drop-wise addition, stirring was continued 
at 73.degree. C. for 4 hours. Then the reaction mixture was cooled, the 
lower organic layer was taken and 550 g of toluene were added to it. It 
was then moved to a flask with a water isolating tube attached, where 
dehydration was performed at reflux temperature, and toluene was removed 
until the solid concentration became 50 wt %. After cooling, 145.3 g (0.9 
mol) of hexamethyldisilazane were added, followed by 6 hours of heating 
with reflux. After cooling, the organic layer was washed with water to 
neutrality, and dehydration was performed using azeotropic process with 
toluene; the solvent was removed, and 324.8 g of light-yellowish 
transparent solid substance were obtained. 
The analytical results of the solid substance are as follows. 
.sup.29 SiNMR .delta. (ppm): 13(0.41Si, br, R'Me.sub.2 SiO.sub.1/2); 
-100(0.07Si, br, ROSiO.sub.3/2); -110(0.52Si, br, SiO.sub.4/2); (R is 
CH.sub.3 CH.sub.2 or H, R' represents CH.sub.2 .dbd.CH(CH.sub.2).sub.4 or 
Me.). 
.sup.13 CNMR .delta. (ppm): 139(0.82C, s, .dbd.CH--); 115(0.82C, s, 
.dbd.CH.sub.2); 59(1.36C, s, --OCH.sub.2 CH.sub.3); 34(1.00C, s, 
Si(CH.sub.2).sub.3 CH.sub.2 --); 33(1.09C, s, Si(CH.sub.2).sub.2 CH.sub.2 
--); 23(1.00C, s, SiCH.sub.2 CH.sub.2 --); 18(2.45C, s, SiCH.sub.2 -- or 
--OCH.sub.2 CH.sub.3); 0(12.30C, s, SiCH.sub.3). 
GPC (gel permeation chromatography): Mw: weight-average molecular 
weight=6.5.times.10.sup.3 ; Mn: number-average molecular 
weight=3.1.times.10.sup.3. 
It was determined that the obtained hexenyl radical-containing silicone 
resin is an organo-silicon polymer with residual hydroxy radicals and 
ethoxy radicals on its terminals and having a chemical configuration 
represented by the average unit formula: 
EQU (CH.sub.2 .dbd.CHC.sub.4 H.sub.8 Me.sub.2 SiO.sub.1/2).sub.0.14 (Me.sub.3 
SiO.sub.1/2).sub.0.54 (SiO.sub.4/2).sub.1.0