JP3155547B2 - Diphenylsiloxane / dimethylsiloxane copolymer and method for producing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel diphenylsiloxane / dimethylsiloxane copolymer, and more particularly to diphenylsiloxane / dimethyl having a silicon-bonded hydrogen atom at only one end of a molecular chain. The present invention relates to a siloxane copolymer and a method for producing the same.

[Prior art] Diphenylsiloxane / dimethylsiloxane copolymers are superior to dimethylpolysiloxane in physical properties such as radiation resistance, heat resistance, flame retardancy and low-temperature flexibility. It's being used. Such a diphenylsiloxane / dimethylsiloxane copolymer is
It can be easily produced by performing a polymerization reaction of cyclic diphenylsiloxane and cyclic dimethylsiloxane in the presence of an alkali metal catalyst such as potassium hydroxide or lithium siliconate.

However, since the above-mentioned polymerization reaction is an equilibrium reaction, a large amount of low-molecular-weight cyclic siloxane is by-produced in the equilibrium state, and the yield of the target diphenylsiloxane-dimethylsiloxane copolymer is low. The molecular weight distribution of the union was calculated by dividing the weight average molecular weight (Mw) by the number average molecular weight (M
This is the value divided by n). ｝ Had the drawback of becoming wider.

The present inventor has previously disclosed in Japanese Patent Application No. 2-114177, diphenylsiloxane with a high yield and a narrow molecular weight distribution.
A method for producing dimethylsiloxane copolymer was proposed.

[Problems to be Solved by the Invention] However, the production method proposed in Japanese Patent Application No. 2-114177 produces a diphenylsiloxane-dimethylsiloxane copolymer having a silicon-bonded hydrogen atom only at one end of a molecular chain. I couldn't.

The inventor of the present invention has intensively studied to solve the above problems, and as a result, has reached the present invention.

An object of the present invention is to provide a novel diphenylsiloxane / dimethylsiloxane copolymer having a silicon-bonded hydrogen atom only at one end of a molecular chain and a method for producing the same.

[Means for Solving the Problem and Action Thereof] An object of the present invention is to provide a compound represented by the following general formula: R (R ₂ SiO) l (Ph ₂ SiO) m (Me ₂ SiO) nA A monovalent hydrocarbon group,
Ph is a phenyl group, Me is a methyl group, A is a diorganohydrogensilyl group or an alkylphenylhydrogengensilyl group, l is an integer of 0 or more, and m is an integer of 3 or more. , N is an integer of 3 or more. A diphenylsiloxane / dimethylsiloxane copolymer represented by the formula: Is achieved.

Hereinafter, the diphenylsiloxane / dimethylsiloxane copolymer of the present invention will be described in detail.

Diphenylsiloxane-dimethylsiloxane copolymer of the present invention have the general _{formula: R (R 2 SiO) l} (Ph 2 SiO) represented by the m (Me ₂ SiO) nA. In the above formula, R is the same or different monovalent hydrocarbon group, specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group; a vinyl group, an allyl group,
An alkenyl group such as a hexenyl group; an aryl group such as a phenyl group, a tolyl group and a xylyl group; and an aralkyl group such as a benzyl group and a phenethyl group. R is preferably a methyl group, a butyl group, a vinyl group or a phenyl group from the viewpoint of ease of production and economy of the diphenylsiloxane / dimethylsiloxane copolymer of the present invention. Also, Ph
Is a phenyl group, Me is a methyl group, and A is a diorganohydrogensilyl group, specifically, dimethylhydrogensilyl, methylphenylhydrogensilyl, diphenylhydrogensilyl and the like. An organohydrogensilyl group is exemplified. l
Is an integer of 0 or more, m is an integer of 3 or more, and n is an integer of 3 or more.

The diphenylsiloxane / dimethylsiloxane copolymer of the present invention comprises: (A) a general formula: R (R ₂ SiO) pLi (where R is the same or different monovalent hydrocarbon group,
p is an integer of 0 or more. (B) General formula: R (R ₂ SiO) rH (where R is the same or different monovalent hydrocarbon group,
r is an integer of 1 or more. A) a polymerization reaction of (C) a mixture of hexaphenylcyclotrisiloxane and hexamethylcyclotrisiloxane in (D) an aprotic organic solvent in the presence or absence of the organosilicon compound represented by (E) can be produced by terminating the polymerization reaction with diorganochlorosilane.

 Hereinafter, the production method of the present invention will be described in detail.

The lithium compound of the component (A) is a polymerization initiator, and is a compound represented by the general formula: R (R ₂ SiO) pLi. In the above formula, R is the same or different monovalent hydrocarbon group, specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group; an alkenyl group such as a vinyl group, an allyl group, and a hexenyl group. Groups; aryl groups such as phenyl, tolyl, and xylyl groups; and monovalent hydrocarbon groups such as aralkyl groups such as benzyl group and phenethyl group. R is a methyl group, a butyl group, or a vinyl group from the viewpoint of economy. Alternatively, it is preferably a phenyl group.
p is an integer of 0 or more. The lithium compound of component (A) wherein p is an integer of 1 or more hydrolyzes triarganochlorosilane or α-chlorodiorganosilopolysiloxane, and this hydrolyzate contains lithium metal, lithium hydroxide or an organic lithium compound. The lithium compound of component (A), in which p is 0, is an organolithium compound, and the organolithium compound itself functions as a polymerization initiator. In the organolithium compound of the component (A) in which p is 0, R is preferably a butyl group. In the production method of the present invention, the addition amount of the component (A) is not particularly limited as long as it is an amount sufficient to carry out the polymerization reaction. Specifically, the number of moles of the component (C), which is a raw material monomer, And (A)
The molar ratio of the components is preferably in the range of 1: 1 to 2000: 1.

The organosilicon compound as the component (B) is a compound represented by the general formula: R (R ₂ SiO) rH, which functions as a molecular weight regulator for the diphenylsiloxane / dimethylsiloxane copolymer of the present invention. In the above formula, R is the same or different monovalent hydrocarbon group, and examples thereof include the same organic groups as described above. r is an integer of 1 or more. The addition amount of the organosilicon compound of the component (B) is arbitrary, but the ratio of the number of moles of the component (A) to the number of moles of the component (B) is preferably in the range of 100: 0 to 0.1: 100. It is particularly preferable that this ratio be in the range of 100: 0 to 0.5: 99.5 because a good polymerization reaction rate can be obtained. Such an organosilicon compound as the component (B) can be easily obtained by hydrolyzing triorganochlorosilane or α-chlorodiorganopolysiloxane. It is not necessary to prepare the organosilicon compound of the component (B) alone. For example, when r is 1 or more, the organosilicon compound of the component (B) has a chemical equivalent or less of lithium metal, lithium hydroxide or an organolithium compound. To prepare a mixture of the lithium compound of the component (A) and the organosilicon compound of the component (B), which can be used in the production method of the present invention.

The mixture of hexaphenylcyclotrisiloxane and hexamethylcyclotrisiloxane as the component (C) is a raw material monomer. In the production method of the present invention, the ratio of the number of moles of hexaphenylcyclotrisiloxane to the number of moles of hexamethylcyclotrisiloxane is not particularly limited,
When the molar ratio of hexaphenylcyclotrisiloxane to the total amount of component (C) is increased, unreacted hexaphenylcyclotrisiloxane and low-molecular-weight cyclic siloxane generated by a side reaction increase, and the desired diphenylsiloxane / dimethylsiloxane is obtained. Since the yield of the copolymer is reduced, the amount of hexaphenylcyclotrisiloxane is preferably 50 mol% or less based on the total amount of the component (C).

The aprotic organic solvent of the component (D) is a solvent used for dissolving the solid component (C) at room temperature.
Examples of the aprotic organic solvent as the component (D) include aromatic solvents such as benzene, toluene, and xylene;
Ether solvents such as tetrahydrofuran and diethyl ether; aliphatic solvents such as hexane and heptane; ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as ethyl acetate and butyl acetate; dimethylformamide, dimethyl sulfoxide and hexamethylphosphoric triamide; Is mentioned. In the production method of the present invention, two or more of the above aprotic organic solvents may be used in combination. For example, when a low-polar aprotic organic solvent such as toluene is used, a polymerization reaction may be performed. It is preferable to use a highly polar aprotic organic solvent such as dimethylformamide, dimethylsulfoxide, and hexamethylphosphoric triamide in combination in order to promote the reaction.

The diorganochlorosilane of the component (E) functions as a neutralizing agent for stopping the polymerization reaction. Such a component (E) may be any substance that reacts with the component (A) to form a stable lithium salt, and examples thereof include diorganochlorosilanes such as dimethylchlorosilane, methylphenylchlorosilane, and diphenylchlorosilane. In the production method of the present invention,
Usually, the conversion of hexamethylcyclotrisiloxane in the component (C) is measured by an analytical means such as gas chromatography, gel permeation chromatography or the like, and the conversion of hexamethylcyclotrisiloxane is 80 to 80%.
When it reaches 100%, more preferably 90-100%,
It is preferable to add the component (E) to stop the polymerization reaction. This is because, when the conversion of hexamethylcyclotrikilocysan reaches 100% and the polymerization reaction is further continued, the molecular weight distribution of the target diphenylsiloxane / dimethylsiloxane copolymer is widened by the rearrangement reaction, and This is because by-products of the molecular weight cyclic siloxane increase.
When diorganochlorosilane is used as the component (E), a diphenylsiloxane / dimethylsiloxane copolymer having a silicon-bonded hydrogen atom at one end of a molecular chain is obtained. (E) A diphenylsiloxane-dimethylsiloxane copolymer having a silicon-bonded hydrogen atom at one end of a molecular chain obtained by using diorganochlorosilane as the component in the presence of an alkene having various organic functional groups and a platinum-based catalyst. By carrying out the hydrosilylation reaction in the above, various organic functional groups can also be introduced into one end of the molecular chain of the diphenylsiloxane / dimethylsiloxane copolymer of the present invention.

Since the diphenylsiloxane / dimethylsiloxane copolymer of the present invention as described above has a silicon-bonded hydrogen atom only at one terminal of a molecular chain, it can be used as a non-crosslinking modifier for a curable organopolysiloxane composition or an organic resin. Available.

[Examples] The present invention will be described with reference to examples. In the examples, "Me" represents a methyl group, and "Ph" represents a phenyl group.
The value of the molecular weight distribution is a value obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn).

Example 1 A four-necked flask was charged with 17.5 g (78.9 mmol) of hexamethylcyclotrisiloxane, 13.4 g (22.5 mmol) of hexaphenylcyclotrisiloxane, and 30 ml of tetrahydrofuran. ℃ or below. Under a dry nitrogen atmosphere, an n-butyllithium n-hexane solution (1.58
8.4 mmol), the reaction solution temperature was set to 40 ° C,
The reaction was allowed to proceed for 3 hours, then the reaction solution temperature was set to 45 ° C., and the reaction was allowed to proceed for 1 hour. The reaction solution was further heated to 50 ° C. for 2 hours. The reaction mixture was subjected to gas chromatography (hereinafter, GL
Abbreviated as C. As a result of the analysis according to the above, when the conversion of hexamethylcyclotrisiloxane became 99%, 0.96 g (10.1 mmol) of dimethylchlorosilane and 0.3 g (3.4 mmol) of triethylamine were added to terminate the polymerization reaction. The reaction mixture was filtered, the filtrate was heated, and the solvent and unreacted raw materials were removed under reduced pressure to obtain a colorless liquid compound. The yield of this compound was 93%. The results of analyzing this compound by ²⁹ Si-nuclear magnetic resonance analysis (hereinafter abbreviated as NMR) and a gel permeation chromatography ｛analyzer: HLC manufactured by Tosoh Corporation
-8020, column: TSK-GEL (GMHX manufactured by Tosoh Corporation)
L), solvent: tetrahydrofuran, detector: UV (254 nm)
Measured using Hereinafter, this is abbreviated as GPC. ｝
The number average molecular weight was 3756 (calculated value 3752) and the value of the molecular weight distribution was 1.29 according to the results of the analysis by (1) and the following method for confirming the molecular chain terminal property. It was found to be a diphenylsiloxane / dimethylsiloxane copolymer represented by the following average formula.

C ₄ H ₉ (Ph ₂ SiO) _8.9 (Me ₂ SiO) _26.4 SiHMe ₂ ○ Confirmation of one end of molecular chain Confirm that the obtained diphenylsiloxane / dimethylsiloxane copolymer has a functional group only at one end of molecular chain. To determine, 5 grams of this copolymer, 0.13 grams (0.66 mmol) of 1,3-divinyltetramethyldisiloxane,
Ten milliliters of tetrahydrofuran and a complex of platinum and 1,3-divinyltetramethyldisiloxane (the amount of platinum metal in the complex was 20 ppm based on the total amount) were added. After heating the reaction mixture for 2 hours and refluxing, a part of the reaction mixture was sampled and subjected to GLC and infrared absorption analysis (hereinafter, I
Abbreviated as R. As a result, no 1,3-divinyltetramethyldisiloxane was confirmed, and no characteristic absorption due to silicon-bonded hydrogen atoms was confirmed.
Analysis of the product after the hydrosilylation reaction by GPC revealed that the product had a number average molecular weight of 6,174 and a molecular weight distribution of 1.30. Here, since the molecular weight of the obtained product is about doubled and the value of the molecular weight distribution is not changed, one end of the molecular chain of the diphenylsiloxane / dimethylsiloxane copolymer is a dimethylsilyl group. It was confirmed that.

[Effect of the Invention] The diphenylsiloxane / dimethylsiloxane copolymer of the present invention is a novel compound having a silicon-bonded hydrogen atom only at one terminal of a molecular chain. It has a feature that a siloxane copolymer can be easily produced.

[Brief description of the drawings]

The gel permeation chromatography chart of the diphenylsiloxane / dimethylmethylsiloxane copolymer obtained in Example 1 is shown by the solid line in FIG. 1, and the diphenylsiloxane / dimethylsiloxane copolymer and 1,3
A gel permeation chromatography chart of the product obtained by the addition reaction with -divinyltetramethylsiloxane is shown by a dotted line. The vertical axis of the gel permeation chromatography chart indicates the intensity of UV and the horizontal axis indicates the retention time.

Claims (2)

(57) [Claims] 1. A general formula: R (R ₂ SiO) ₁ (Ph ₂ SiO) m (Me ₂ SiO) nA, wherein R is the same or different monovalent hydrocarbon group,
Ph is a phenyl group, Me is a methyl group, A is a diorganohydrogensilyl group, l is an integer of 0 or more, m is an integer of 3 or more, and n is an integer of 3 or more. is there. A diphenylsiloxane / dimethylsiloxane copolymer represented by the formula: (A) a general formula: R (R ₂ SiO) pLi (wherein R is the same or different monovalent hydrocarbon group,
p is an integer of 0 or more. (B) General formula: R (R ₂ SiO) rH (where R is the same or different monovalent hydrocarbon group,
r is an integer of 1 or more. A) a polymerization reaction of (C) a mixture of hexaphenylcyclotrisiloxane and hexamethylcyclotrisiloxane in (D) an aprotic organic solvent in the presence or absence of the organosilicon compound represented by (E) The method for producing a diphenylsiloxane / dimethylsiloxane copolymer according to claim 1, wherein the polymerization reaction is terminated by diorganochlorosilane.