JP4485710B2 - Process for producing branched organopolysiloxane - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a branched organopolysiloxane.
[0002]
[Prior art]
Branched organopolysiloxane is useful as a base polymer for addition curable silicone compositions, and addition curable silicone compositions cure to form silicone gels and silicone rubbers with excellent electrical properties, cold resistance, etc. It is used as a sealant, filler or coating agent for an electrical / electronic component, a semiconductor element, and a protective agent for an optical semiconductor insulation coating.
[0003]
As a general method for producing a branched organopolysiloxane, JP-A-58-7452 discloses (CH ₃ ) ₂ SiO _2/2 units, CH ₃ SiO _3/2 units, (CH ₃ ) ₃ SiO ₁ A method for preparing an organopolysiloxane mixture containing hydrates of organopolysiloxanes containing _{/ 2} units by using alkali equilibration is disclosed (a hydrate is a chlorosilane composed of each unit). A co-hydrolyzed condensate of
[0004]
However, the organopolysiloxane that is this branching raw material has a large amount of (CH ₃ ) ₃ SiO _1/2 units that are molecular end sources, and attempts to change the amount of branching in the target polymer. In this case, the amount of the molecular end source was changed accordingly, and it was very difficult to adjust the molar ratio (viscosity) of the siloxane units constituting the branched organopolysiloxane. JP-A-2-269771 and JP-A-4-25529 disclose a branched organopolysiloxane from a branched raw material consisting of only (CH ₃ ) ₂ SiO _2/2 units and CH ₃ SiO _3/2 units. The resulting preparation is disclosed. However, there are problems that the branched raw material itself is unstable and that synthesis is not easy, and that a large amount of branched raw material is required in the production of branched organopolysiloxane.
[0005]
[Problems to be solved by the invention]
Then, an object of this invention is to provide the manufacturing method of the branched organopolysiloxane which can control molecular composition easily as desired.
[0006]
[Means for Solving the Problems]
When the present inventors use an organohydrogenpolysiloxane having a CH ₃ (H) SiO _2/2 unit as a part of the starting organopolysiloxane and perform an equilibration reaction using an alkali catalyst in the presence of water. , CH ₃ (H) SiO _2/2 units in the polymerization process, CH ₃ SiO ₃ which is converted to CH ₃ (HO) SiO _2/2 units with an alkaline catalyst and water, and further polycondensation bring branched in the polymer We paid attention to the production of branched organopolysiloxane using the production of _{/ 2} units. According to this method, it has been found that the molecular composition of the target branched organopolysiloxane can be controlled so as to be hardly affected by the amount of terminal groups contained in the starting organopolysiloxane. The present invention has been reached.
[0007]
That is, the present invention equilibrates an organopolysiloxane mixture containing an organohydrogenpolysiloxane containing at least one CH ₃ (H) SiO _2/2 unit in one molecule using an alkali catalyst in the presence of water. Provided is a method for producing a branched organopolysiloxane having at least one CH ₃ SiO _3/2 unit in a molecule, characterized by being subjected to a reaction. Moreover, the branched organopolysiloxane manufactured by this manufacturing method is provided.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
[0009]
[material]
The organohydrogenpolysiloxane used as a raw material (branched raw material) in the present invention generally has the following average composition formula (I):
R ¹ _a H _b SiO _{(4-ab) / 2} (I)
[Wherein, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group not containing an aliphatic unsaturated group, and a and b are 0 <a ≦ 3, 0 <b ≦ 2, and 0 < A positive number where a + b <4. And is an organohydrogenpolysiloxane having at least one hydrogen atom directly bonded to a silicon atom, that is, a CH ₃ (H) SiO _2/2 unit.
[0010]
In the average composition formula (I), as the unsubstituted monovalent hydrocarbon group represented by R ¹ , for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, Usually, alkyl groups such as pentyl group, hexyl group, heptyl group and octyl group, cycloalkyl groups such as cyclohexyl group, aryl groups such as phenyl group and tolyl group, aralkyl groups such as benzyl group and 2-phenylethyl group, etc. Examples are those having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. Examples of the substituted monovalent hydrocarbon group include chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, α, α, α-trifluorotolyl group, chlorobenzyl group, and promopropyl. Examples thereof include a halogenated hydrocarbon group such as a group, and a cyano hydrocarbon group such as a cyanoethyl group and a cyanopropyl group. Generally preferred are a methyl group, a phenyl group, and a 3,3,3-trifluoropropyl group.
[0011]
Specific examples are shown below, but cyclic organohydrogenpolysiloxanes are preferred as branching raw materials because they do not affect the amount of terminal groups. Further, the higher the degree of polymerization of the linear organohydrogenpolysiloxane, the less the influence of the terminal group amount. Furthermore, the organohydrogenpolysiloxane having a dimethylhydrogensiloxy unit at the molecular terminal is converted to a dimethylsiloxane unit in the molecular main chain by hydrolysis of the dimethylhydrogensiloxy unit. Few.
[0012]
[CH ₃ (H) SiO] _n , [CH ₃ (H) SiO] _k [(CH ₃ ) ₂ SiO] _l
(CH ₃ ) ₃ SiO [CH ₃ (H) SiO] _m Si (CH ₃ ) ₃
(CH ₃ ) ₃ SiO [CH ₃ (H) SiO] _p [(CH ₃ ) ₂ SiO] _q Si (CH ₃ ) ₃
H (CH ₃ ) ₂ SiO [CH ₃ (H) SiO] _p [(CH ₃ ) ₂ SiO] _q Si (CH ₃ ) ₂ H
(CH ₃ ) ₃ SiO [CH ₃ (H) SiO] _p [(CH ₃ ) ₂ SiO] _q [(C ₆ H ₅ ) ₂ SiO] _r Si (CH ₃ ) ₃
(Wherein n is 4 or more, k, l, m, p, q, r are positive integers, preferably n is 4 to 20, k + 1 is 4 to 20, m is 1 to 200, and p + q is 2 to 200, p + q + r is an integer of 3 to 200, more preferably, n is 4 to 10, k + 1 is 4 to 10, m is 1 to 100, p + q is 2 to 100, and p + q + r is an integer of 3 to 100 .)
[0013]
In the method of the present invention, the above-mentioned organohydrogenpolysiloxane is subjected to an equilibration reaction together with other organopolysiloxane. The molecular structure of the organopolysiloxane used in combination with the organohydrogenpolysiloxane is determined according to the molecular structure of the target branched organopolysiloxane.
[0014]
Organopolysiloxanes other than the above-mentioned organohydrogenpolysiloxane (branched raw material) are not particularly limited in their meanings. For example, the following general formula (2)
R ² ₃ SiO [R ³ ₂ SiO] _c SiR ⁴ ₃ (2)
(In the formula, R ^{2 to} R ⁴ are substituted or unsubstituted monovalent hydrocarbon groups which may be the same or different, and c is an integer of 0 to 200, preferably 1 to 100.)
The organopolysiloxane represented by these is mentioned.
[0015]
Examples of the substituted or unsubstituted monovalent hydrocarbon group represented by R ^{2 to} R ⁴ in the general formula (2) include the same ones as exemplified for the R ¹ , but the unsubstituted monovalent carbon group can be exemplified. Examples of the hydrogen group include methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, isobutyl groups, tert-butyl groups, pentyl groups, hexyl groups, cyclohexyl groups, octyl groups and other alkyl groups, phenyl groups, and tolyl groups. In addition to aralkyl groups such as aryl groups such as benzyl group and phenylethyl group, fats such as alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, isobutenyl group, hexenyl group and cyclohexenyl group Group unsaturated monovalent hydrocarbon group.
[0016]
Further, as a raw material other than the branched raw material, the following general formula (3)
[R ⁵ ₂ SiO] _d (3)
(In the formula, R ⁵ is a substituted or unsubstituted monovalent hydrocarbon group, and d is an integer of 3 to 10, preferably 4 to 7.)
The cyclic organopolysiloxane represented by these is mentioned.
[0017]
Examples of the substituted or unsubstituted monovalent hydrocarbon group represented by R ⁵ in the general formula (2) include the same ones exemplified as the above R ^{2 to} R ⁴ , but unsubstituted monovalent carbon groups. Examples of the hydrogen group include methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, isobutyl groups, tert-butyl groups, pentyl groups, hexyl groups, cyclohexyl groups, octyl groups and other alkyl groups, phenyl groups, and tolyl groups. In addition to aralkyl groups such as aryl groups such as benzyl group and phenylethyl group, fats such as alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, isobutenyl group, hexenyl group and cyclohexenyl group Group unsaturated monovalent hydrocarbon group.
[0018]
[Equilibration reaction]
The production method of the present invention is known per se in the presence of an alkali catalyst except that the above-mentioned organohydrogenpolysiloxane is used as a branching raw material, and this is mixed with other organopolysiloxane and water. This is carried out by the equilibration reaction. For example, it can be carried out at room temperature to 180 ° C. without using a solvent, and polymerization by an equilibration reaction may be carried out using an appropriate solvent. Examples of the alkali catalyst include alkali metal compounds such as NaOH, KOH, sodium silanolate and potassium silanolate, alkylphosphonium hydroxide such as tetrabutylphosphonium hydroxide (Bu ₄ POH), tetramethylammonium hydroxide (Me ₄ NOH) And alkyl ammonium hydroxide such as 1,8-diazabicyclo (5,4,0) undecene-7 (DBU).
[0019]
In general, when alkylphosphonium hydroxide or alkylammonium hydroxide is used as a catalyst, the equilibration reaction is carried out at a relatively low temperature, for example, 100 to 130 ° C., preferably 110 to 120 ° C. It is used at a ratio of 0.001 to 0.1% by weight, preferably 0.001 to 0.04% by weight, based on the starting organopolysiloxane. Further, when an alkali metal compound is used as a catalyst, an equilibration reaction is performed at a relatively high temperature, for example, 130 to 180 ° C., and this alkali catalyst is composed of silicon atoms and alkali metal atoms ( Expressed as a molar ratio to M), Si / M is used in an amount of 1000 to 100,000.
[0020]
The amount of the organohydrogenpolysiloxane used as the branching raw material depends on the degree of branching of the branched organopolysiloxane to be obtained, and the amount can be determined from the content of hydrogen atoms bonded to silicon atoms in the organohydrogenpolysiloxane. it can. Water is necessary for converting a hydrogen atom bonded to a silicon atom into a silanol group. The amount used is preferably 1/100 to 1 (molar ratio) of CH ₃ (H) SiO _2/2 units constituting the branch because water is regenerated by a condensation reaction between silanol groups or the like.
[0021]
After completion of the reaction, the catalyst is neutralized and filtered, and then the filtrate is subjected to purification such as distillation to obtain the target branched organopolysiloxane.
[0022]
According to the method for producing a branched organopolysiloxane of the present invention, as a typical example, the molecular composition of the branched organopolysiloxane to be produced is 70 to 98 mol% of R ₂ SiO _2/2 units, CH ₃ SiO _{3 /} These siloxanes are composed of 0.1 to 15 mol% of ₂ units and 0.1 to 15.0 mol% of R (CH ₃ ) ₂ SiO _1/2 units (wherein R is a methyl group, a phenyl group or an alkenyl group). A branched organopolysiloxane having such a molecular composition can be obtained by selecting the organopolysiloxane mixture so that the total is 100 mol% in units. Here, among the groups represented by R, examples of the alkenyl group include a vinyl group, an allyl group, an isopropenyl group, a butenyl group, and a hexenyl group, and a vinyl group is particularly preferable. The viscosity of the branched organopolysiloxane is not particularly limited, but the viscosity at 25 ° C. is preferably 10 to 100000 mPa · s.
[0023]
The branched organopolysiloxane having such a molecular composition has a characteristic that it does not solidify even at a low temperature of −80 ° C. Therefore, when this branched organopolysiloxane is used as the main agent (base polymer) and derived into an addition reaction curable composition, a silicone rubber and a silicone gel excellent in low temperature characteristics can be obtained. In addition, since the polymer itself is already branched, when this branched organopolysiloxane is derived into an addition reaction curable composition as a main agent (base polymer), very fast curing characteristics can be obtained. It is useful in terms of
[0024]
The branched organopolysiloxane thus obtained contains HO (H) (CH ₃ ) SiO _1/2 units, H (CH ₃ ) ₂ SiO _1/2 units, HO (CH ₃ ) SiO _{2 / One} unit or two or more types of ₂ units and H (CH ₃ ) SiO _2/2 units may be contained.
[0025]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited to these examples. The viscosity is a value at 25 ° C. “Parts” means parts by weight.
[0026]
Example 1
(CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] ₃ Si (CH ₃ ) ₃ 73 g (190 mmol), [(CH ₃ ) ₂ SiO] ₄ 884 g (2986 mmol), (CH ₃ ) ₃ SiO [CH ₃ ( H) SiO] ₃₈ Si (CH ₃ ) ₃ 25.6 g (10.5 mmol) and a siloxane mixture comprising 0.5 g of water (the composition ratio of each siloxane unit in the mixture is (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂ SiO and CH ₃ (H) SiO are 3.0 mol%, 94.0 mol% and 3.0 mol% (total 100 mol%, respectively). Then, a polymerization reaction was performed at 150 ° C. for 8 hours, and then a mixed solution of 0.17 g of (CH ₃ ) ₃ SiCl and 1 g of [(CH ₃ ) ₃ Si] ₂ NH was added to the reaction solution, followed by stirring at 50 ° C. for 2 hours. Neutralized, and then heated to 150-160 ° C for 5 hours under a reduced pressure of 266 Pa (2 mmHg) to distill off the low boiling point, and the product salt was filtered off. The viscosity was 900 mPa · s and it was transparent. An organopolysiloxane was obtained.
[0027]
^{According to 29} Si-NMR measurement, the ratio of each siloxane unit in the obtained polymer was (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂ SiO and CH ₃ SiO _1.5 3 mol%, 94 mol% and 3 mol%, respectively. Mol% (total 100 mol%), which was as set.
[0028]
Example 2
(CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] ₃ Si (CH ₃ ) ₃ 73 g (190 mmol), [(CH ₃ ) ₂ SiO] ₄ 886 g (2986 mmol), [CH ₃ (H) SiO] ₄ 24 g (100 mmol) and a siloxane mixture consisting of 0.5 g of water (the ratio of each siloxane unit in the mixture is (CH ₃ ) ₃ SiO _0.5 mol%, (CH ₃ ) ₂ SiO mol%, and CH ₃ (H) SiO 1% of 3% KOH-dimethylpolysiloxanolate was added to 2.9 mol%, 94.1 mol%, and 3.0 mol%, respectively, and this reaction was carried out at 150 ° C. for 8 hours under a nitrogen stream. A liquid mixture of (CH ₃ ) ₃ SiCl 0.17 g and [(CH ₃ ) ₃ Si] ₂ NH 1 g was added to the liquid, followed by neutralization by stirring at 50 ° C. for 2 hours, and then 266 Pa (2 mmHg). When heated at 150-160 ° C. under reduced pressure for 5 hours to distill off the low-boiling components and the produced salt was filtered off, a transparent organopolysiloxane having a viscosity of 1400 mPa · s was obtained.
[0029]
^{According to 29} Si-NMR measurement, the proportion of each siloxane unit in the organopolysiloxane was (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂ SiO, and CH ₃ SiO _1.5 2.9 mol%, 94.1 mol% and 3 Mol%, which was as set.
[0030]
Example 3
(CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] ₃ Si (CH ₃ ) ₃ 174 g (453 mmol), [(CH ₃ ) ₂ SiO] ₄ 680 g (2297 mmol), (CH ₃ ) ₃ SiO [CH ₃ ( H) SiO] ₃₈ Si (CH ₃ ) ₃ 77 g (31.5 mmol), CH ₂ ═CH (CH ₃ ) ₂ SiO [(CH ₃ ) ₂ SiO] ₁₀ Si (CH ₃ ) ₂ CH═CH ₂ 46 g (50.0 mmol ) And 2.5 g of water (the ratio of each siloxane unit in the mixture is (CH ₂ = CH) (CH ₃ ) ₂ SiO _0.5 , (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂ SiO and ( CH ₃ ) (H) SiO is 0.75 mol%, 7.3 mol%, 82.95 mol% and 9.0 mol%, respectively, and 1 g of 3% KOH-dimethylpolysiloxanolate is added at 150 ° C. under a nitrogen stream. After the polymerization reaction for 8 hours, a mixed solution of (CH ₃ ) ₃ SiCl 0.17 g and [(CH ₃ ) ₃ Si] ₂ NH 1 g was added to this reaction solution, and the mixture was neutralized by stirring at 50 ° C. for 2 hours. Then, the mixture was heated to 150-160 ° C. for 5 hours under a reduced pressure of 266 Pa (2 mmHg), the low boiling point was distilled off, and the resulting salt was filtered off to obtain a transparent organopolysiloxane having a viscosity of 2000 mPa · s. Gain It was.
[0031]
The ratio of each siloxane unit set (intended) is CH ₂ ═CH (CH ₃ ) ₂ SiO _0.5 , (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂ SiO and CH ₃ SiO _1.5 0.75 mol%, While the composition of each siloxane unit in the obtained polymer was 7.3 mol%, 82.95 mol%, and 9 mol%, the composition of CH ₂ ═CH (CH ₃ ) ₂ SiO _{0.5 was} determined by ²⁹ Si-NMR measurement. , (CH ₃ ) ₃ SiO _0.5 , H (CH ₃ ) ₂ SiO _0.5 , (CH ₃ ) ₂ SiO and CH ₃ SiO _1.5 are 0.7 mol%, 7 mol%, 0.35 mol%, 82.85 mol% and 9.1 mol%, respectively. Met.
[0032]
100 parts of the organopolysiloxane thus obtained have a content of hydrogen atoms bonded to silicon atoms of about 0.068% by weight, 10 parts of dimethylpolysiloxane having a dimethylhydrogensiloxane unit at the end, chloroplatinic acid A composition in which 0.05 part of a vinylsiloxane complex (platinum content: 1% by weight), 0.0009 part of tetramethylethylenediamine and 0.045 part of 1-ethynyl-1-cyclohexanol were previously mixed was uniformly mixed. The resulting composition was cured by heating at 130 ° C. for 30 minutes to obtain a transparent gel. The penetration of this gel was 20 with a ¼ scale penetration meter.
[0033]
Example 4
(CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] ₃ Si (CH ₃ ) ₃ 14 g (36.5 mmol), [(CH ₃ ) ₂ SiO] ₄ 590 g (1993 mmol), [(C ₆ H ₅ ) ₂ SiO ] ₄ 36 g (45.5 mmol), (CH ₃ ) ₃ SiO [CH ₃ (H) SiO] ₃₈ Si (CH ₃ ) ₃ 8.7 g (3.56 mmol), CH ₂ = CH (CH ₃ ) ₂ SiO [(CH ₃ ) ₂ SiO] ₁₀ Si (CH ₃ ) ₂ CH═CH _{2 A} siloxane mixture comprising 38.3 g (41.4 mmol) and water 0.5 g (the composition ratio of each siloxane unit in the mixture is (CH ₂ = CH) (CH ₃ ) ₂ SiO _0.5 , (CH ₃ ) ₃ SiO _0.5 , (C ₆ H ₅ ) ₂ SiO, (CH ₃ ) ₂ SiO, and (CH ₃ ) (H) SiO are 0.85 mol%, 0.9 mol%, 1 mol of 3% KOH-dimethylpolysiloxanolate was added to 1 mol%, 2.1 mol%, 94.65 mol%, and 1.5 mol%), and the polymerization reaction was carried out at 150 ° C. for 8 hours in a nitrogen stream. Add a mixture of (CH ₃ ) ₃ SiCl 0.17 g and [(CH ₃ ) ₃ Si] ₂ NH 1 g, stir at 50 ° C for 2 hours to neutralize, then under reduced pressure of 266 Pa (2 mmHg) At 150-160 ° C for 5 hours to distill off the low boiling point and filter the resulting salt by filtration. When the viscosity is transparent organopolysiloxane was obtained in 1000mPa · s.
[0034]
^{According to 29} Si-NMR measurement, the proportion of each siloxane unit in the organopolysiloxane was CH ₂ = CH (CH ₃ ) ₂ SiO _0.5 , (CH ₃ ) ₃ SiO _0.5 , (C ₆ H ₅ ) ₂ SiO _0.5 , And (CH ₃ ) ₂ SiO and CH ₃ SiO _1.5 were 0.85 mol%, 0.9 mol%, 2.1 mol%, 94.65 mol%, and 1.5 mol%, respectively, as set.
[0035]
100 parts of the organopolysiloxane thus obtained were bonded to a silicon atom, 60 parts of an organopolysiloxane having a trimethylsiloxy group at the end and containing 3 mol% of a diphenylsiloxane unit and having a viscosity of 700 mPa · s. 6.9 parts by weight of dimethylpolysiloxane having a hydrogen atom content of about 0.068% by weight and dimethylhydrogensiloxane units at the end, the content of hydrogen atoms bonded to silicon atoms is about 0.04% by weight, and 50% at the end 12 parts of dimethylpolysiloxane having a dimethylhydrogensiloxy unit, 0.1 part of chloroplatinic acid-vinylsiloxane complex (platinum content: 1% by weight), 0.0012 part of tetramethylethylenediamine and 0.06 part of 1-ethynyl-1-cyclohexanol Mixing uniformly gave a composition. The resulting composition was cured by heating at 130 ° C. for 30 minutes to obtain a transparent gel. The penetration of this gel was 115 with a 1/4 scale penetration meter.
[0036]
Comparative Example 1
[(CH ₃ ) ₂ SiO] ₃ [(CH ₃ ) (OH) SiO] was used as a branching raw material to prepare an oil having the same setting composition as in Example 1 with the following composition.
(CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] ₃ Si (CH ₃ ) ₃ 73 g (190 mmol), [(CH ₃ ) ₂ SiO] ₄ 754 g (2547 mmol) and [(CH ₃ ) ₂ SiO] ₃ [ (CH ₃ ) (OH) SiO] A siloxane mixture comprising 113 g (379 mmol) (the constituent ratio of each siloxane unit in the mixture is (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂ SiO, and (CH ₃ ) ( OH) SiO is 3.0 mol%, 94.0 mol%, and 3.0 mol%, respectively), polymerization, neutralization, distilling off the low-boiling components and filtering according to Example 1 to give a viscosity of 750 mPa -Transparent organopolysiloxane was obtained in s, and finished to a low viscosity product as compared with Example 1.
[0037]
The set composition of each siloxane in the target organopolysiloxane is 3 mol%, 94 mol%, and 3 mol% of (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂ SiO, and CH ₃ SiO _1.5 , respectively. In contrast, the proportion of each siloxane in the obtained polymer was determined by ²⁹ Si-NMR measurement to detect HO (CH ₃ ) ₂ SiO _0.5 group as a terminal group, and (CH ₃ ) ₃ SiO _0.5 , HO (CH ₃ ) ₂ SiO _0.5 , (CH ₃ ) ₂ SiO, and CH ₃ SiO _1.5 were 3 mol%, 0.5 mol%, 93.5 mol%, and 3 mol%, respectively.
[0038]
Comparative Example 2
[(CH ₃ ) ₂ SiO] ₃ [(CH ₃ ) (OH) SiO] was used as a branching raw material to prepare an oil having the same setting composition as in Example 4 with the following composition.
(CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] ₃ Si (CH ₃ ) ₃ 15.4 g (40.1 mmol), [(CH ₃ ) ₂ SiO] ₄ 560 g (1892 mmol), [(C ₆ H ₅ ) ₂ SiO] ₄ 36 g (45.5 mmol), [(CH ₃ ) ₂ SiO] ₃ [(CH ₃ ) (OH) SiO] 40 g (134 mmol), CH ₂ = CH (CH ₃ ) ₂ SiO [(CH ₃ ) ₂ SiO ] ₁₀ Si (CH ₃ ) ₂ CH = CH ₂ 38.3 g (41.4 mmol) of siloxane mixture consisting of 0.5 g of water (the composition ratio of each siloxane unit in the mixture is (CH ₂ = CH) (CH ₃ ) ₂ SiO _0.5 , (CH ₃ ) ₃ SiO _0.5 , (C ₆ H ₅ ) ₂ SiO, (CH ₃ ) ₂ SiO, and (CH ₃ ) (HO) SiO are 0.85 mol%, 0.9 mol%, 2.1 mol%, 94.65 mol% and 1.5 mol%) were used for polymerization, neutralization, distilling off the low-boiling components and filtering to obtain a transparent organopolysiloxane having a viscosity of 400 mPa · s. Compared with Example 4, it finished in a low viscosity product.
[0039]
^{By 29} Si-NMR measurement, HO (CH ₃ ) ₂ SiO _0.5 group was detected as a terminal group in the obtained organopolysiloxane, and the ratio of each siloxane was CH ₂ ═CH (CH ₃ ) ₂ SiO _0.5 , (CH ₃ ) ₃ SiO _0.5 , HO (CH ₃ ) ₂ SiO _0.5 , (C ₆ H ₅ ) ₂ SiO, (CH ₃ ) ₂ SiO, and CH ₃ SiO _1.5 are 0.85 mol%, 0.9 mol%, 0.35 mol%, They were 2.1 mol%, 93.4 mol%, and 1.5 mol%.
[0040]
The organopolysiloxane thus obtained was blended with other materials in the same manner as in Example 4, and the obtained composition was cured by heating at 130 ° C. for 30 minutes. Was obtained, but swollen by foaming. Although the penetration of this gel-like material could not be measured accurately, it was about 70 with a 1/4 scale penetration meter.
[0041]
【The invention's effect】
As described above, according to the production method of the present invention, the molecular composition of the obtained branched organopolysiloxane can be easily controlled as desired. That is, a branched organopolysiloxane having a desired viscosity can be easily obtained because the influence of the amount of terminal groups derived from the starting organopolysiloxane can be greatly suppressed.

Claims (2)

An organopolysiloxane mixture containing an organohydrogenpolysiloxane containing at least one CH ₃ (H) SiO _2/2 unit in one molecule is subjected to an equilibration reaction using an alkali catalyst in the presence of water. A method for producing a branched organopolysiloxane having at least one CH ₃ SiO _3/2 unit in the molecule. The resulting branched organopolysiloxane has a molecular composition of R ₂ SiO _2/2 units of 70 to 98 mol%, CH ₃ SiO _3/2 units of 0.1 to 15 mol%, and R (CH ₃ ) ₂ SiO _1/2 units of 0.1 The organopolysiloxane mixture is selected so that the total amount of these siloxane units is 100 mol%. The branched organopolysiloxane according to claim 1, wherein a branched organopolysiloxane having such a molecular composition is obtained.