JP3131216B2 - Organopolysiloxane and method for producing the same - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel organopolysiloxane, and more particularly, to a novel organopolysiloxane having a star-shaped chemical structure and having a functional group at a molecular chain terminal. The present invention relates to a siloxane and a method for producing the siloxane.

[Prior Art] Conventionally, an organopolysiloxane having a chemical structure controlled in a star shape and having a functional group at a molecular chain terminal has been reported by Dickstein (William. H. Dickstein) et al. Macromolecules
22 (1989) 3886]. In this method, a living anionic polymerization reaction of hexamethylcyclotrisiloxane is performed using a silylated organolithium compound having an amino group as a polymerization catalyst, and the polymerization reaction is stopped by silicon tetrachloride.
Thereafter, desilylation of the amino group is performed. This production method is represented by a chemical reaction formula. In the formula, Me represents a methyl group, and n represents a positive integer.

[Problems to be Solved by the Invention] However, the organopolysiloxane obtained by the above-mentioned production method has a formula in which a functional group at a molecular chain terminal is derived from the production method. However, an organopolysiloxane having a star-shaped chemical structure having various functional groups at the molecular chain terminals could not be obtained. In addition, in order to prepare an organolithium compound as a polymerization catalyst, a large amount of s-butyllithium, which is difficult to handle, must be used, and the above production method is not suitable for mass synthesis.

The present inventors have made intensive studies to solve the above problems, and have reached the present invention.

That is, an object of the present invention is to provide a novel organopolysiloxane having a chemical structure controlled in a star shape and having a functional group at a molecular chain terminal, and a method for producing the same.

[Means for Solving the Problems and Actions] The object of the present invention is to provide a compound represented by the following general formula (Wherein, R ¹ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, R ² is an alkylene group having 2 or more carbon atoms, and R ³ is the same or different monovalent hydrocarbon group) A is a hydrogen atom, dimethylsilyl group, dimethylvinylsilyl group, dimethyl (γ-acryloxypropyl) silyl group, dimethyl (γ-glycidoxypropyl)
Silyl group or dimethyl (γ-mercaptopropyl)
A is a silyl group, a is 0 or 1, and m is an integer of 3 or more. ) An organopolysiloxane represented by the formula: Is achieved.

Hereinafter, the organopolysiloxane of the present invention will be described.

The organopolysiloxane of the present invention has the general formula: Indicated by In the above formula, R ¹ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, specifically,
Alkyl groups such as methyl group, ethyl group and propyl group; aryl groups such as phenyl group and tolyl group; aralkyl groups such as benzyl group and phenethyl group; and methyl group and phenyl group from the production of organopolysiloxane. preferable. R ² is an alkylene group having 2 or more carbon atoms, and specific examples include a methylmethylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, and a hexylene group. R ³ is the same or different monovalent hydrocarbon group,
Specifically, alkyl groups such as methyl group, ethyl group and propyl group; alkenyl groups such as vinyl group, allyl group, butenyl group, hexenyl group and decenyl group; aryl groups such as phenyl group, tolyl group and xylyl group; And aralkyl groups such as benzyl group and phenethyl group. A is a hydrogen atom, a dimethylsilyl group, a dimethylvinylsilyl group, a dimethyl (γ-acryloxypropyl) silyl group, a dimethyl (γ
-Glycidoxypropyl) silyl group or dimethyl (γ-mercaptopropyl) silyl group. a is 0 or 1, and when a is 0, the organopolysiloxane of the present invention has a four-branched star chemical structure;
Is 1 and has a star-shaped chemical structure branched in three directions. M is an integer of 3 or more. Such an organopolysiloxane of the present invention has a star-shaped chemical structure, and has a functional group at a molecular chain terminal. Therefore, the organopolysiloxane is also used as a modifier for various organic resins, as a curable organopolysiloxane composition. Expected as a crosslinker or plasticizer.

Such an organopolysiloxane of the present invention has the following general formula (A): In the formula, R ¹ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, R ² is an alkylene group having 2 or more carbon atoms, and B is an alkali metal or hydrogen atom ( However, at least one of B is an alkali metal.)
And a is 0 or 1, and n is an integer of 0 or more. Using an alkali metal salt of an organopolysiloxane represented by 重合 as a polymerization catalyst, (B) a general formula: (Wherein, R ¹ is a same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, R ² is an alkylene group having 2 or more carbon atoms, a is 0 or 1, n is an integer of 0 or more.) In the presence or absence of an organopolysiloxane represented by the following formula (C): (Wherein, R ³ is the same or different monovalent hydrocarbon group.) After the polymerization reaction of the organocyclosiloxane represented by the following formula (D), acid, dimethylchlorosilane, dimethylphenylchlorosilane, or dimethylvinylchlorosilane is used. It can be easily produced by stopping the polymerization reaction.

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

The alkali metal salt of the organopolysiloxane of the component (A) functions as a polymerization catalyst, and the alkali metal salt of such an organopolysiloxane has a general formula: Indicated by In the above formula, R ¹ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, and includes the same organic groups as described above. R ² is an alkylene group having 2 or more carbon atoms, and examples thereof include the same organic groups as described above. B is an alkali metal or hydrogen atom, and specifically includes sodium, potassium, and lithium, and lithium is particularly preferable because the polymerization reaction is non-equilibrium. Here, (A)
In the components, at least one of B must be an alkali metal. a is 0 or 1, and n is an integer of 0 or more. Such an alkali metal salt of an organopolysiloxane is obtained by subjecting tetrakis (diorganosiloxy) silane and diorganoalkenylchlorosilane to a hydrosilylation reaction in the presence of a platinum-based catalyst, and subjecting the resulting product to a basic dilute aqueous solution. It is easily obtained by hydrolyzing and then reacting the organopolysiloxane having a silanol group obtained by the hydrolysis with an alkali metal compound. Further, instead of diorganoalkenylchlorosilane, one end of the molecular chain is a silicon-bonded alkenyl group, and the other end of the molecular chain is obtained similarly using an organopolysiloxane having a silicon-bonded chlorine atom. . In the hydrosilylation, it is preferable to use a silane having an alkenyl group or an organopolysiloxane in a slight excess of the stoichiometric amount with respect to tetrakis (diorganosiloxy) silane. Further, when the organopolysiloxane having a silanol group is reacted with an alkali metal compound, n-butyllithium is most preferable as the alkali metal compound from the viewpoint of economy and reactivity. The amount of the alkali metal salt of the organopolysiloxane as the component (A) is not particularly limited as long as it is sufficient to carry out the polymerization reaction in the production method of the present invention.

The organopolysiloxane of the component (B) functions as a molecular weight regulator, and the silanol group in the component (B) causes an exchange reaction with the alkali metal silanolate in the component (A) at a very high rate. work. The organopolysiloxane of the component (B) has a general formula: Indicated by In the above formula, R ¹ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, and includes the same organic groups as described above. R ² is an alkylene group having 2 or more carbon atoms, and examples thereof include the same organic groups as described above. a is 0 or 1, and n is an integer of 0 or more. The organopolysiloxane of the component (B) can be easily prepared by subjecting tetrakis (diorganosiloxy) silane and diorganoalkenylchlorosilane to a hydrosilylation reaction in the presence of a platinum-based catalyst, and hydrolyzing this in a basic dilute aqueous solution. Is obtained. Alternatively, instead of diorganoalkenylchlorosilane, an organopolysiloxane having a silicon-bonded alkenyl group at one end of the molecular chain and a silicon-bonded chlorine atom at the other end of the molecular chain can be obtained in the same manner.

In the production method of the present invention, it is not necessary to separately prepare the component (A) and the component (B), and when producing the alkali metal salt of the organopolysiloxane of the component (A), the silanol in the starting organopolysiloxane is used. By reacting with a smaller number of moles of the lithium metal compound than the number of moles of the group, the mixture can be prepared as a mixture of the component (A) and the component (B). The blending amount of the component (B)
The ratio of the number of moles of the alkali metal in the component (A) to the number of moles of the silanol group in the component (B) is preferably in the range of 100: 0 to 0.1: 100, and 0.5: 99.5 to 100: 0. Within this range, a favorable polymerization reaction rate can be obtained, and the expensive polymerization catalyst of the component (A) can be saved, which is preferable.

The organocyclosiloxane of the component (C) is known as a monomer for a non-equilibrium polymerization reaction, and has a general formula: Indicated by In the above formula, R ³ is the same or different monovalent hydrocarbon group, and includes the same organic group as described above. In view of easy availability of the component (C), R ³ is a methyl group, a phenyl group or It is preferably a vinyl group. Here, the polymerization reaction conditions in the production method of the present invention vary depending on the organocyclosiloxane used as the component (C). For example, when hexamethylcyclotrisiloxane is used, the temperature is 0 to 30 ° C. in a solvent. At 1 to 50 hours. In this case, the solvent that can be used may be an aprotic solvent, and specific examples thereof include aromatic solvents such as benzene, toluene, and xylene; ether solvents such as tetrahydrofuran and diethyl ether; hexane;
Examples include aliphatic solvents such as heptane; ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as ethyl acetate and butyl acetate; and dimethylformamide, dimethylsulfoxide and hexamethylphosphoric triamide. The use of a combination of two or more solvents often gives good results. For example, when a low-polarity solvent such as toluene is used, dimethylformamide, dimethylsulfoxide, It is preferable to add a highly polar solvent such as hexamethylphosphoric triamide. Of the polymerization reaction conditions, the reaction temperature and time need to be carefully controlled to minimize the rate of rearrangement reaction,
This means that if the polymerization reaction is not a non-equilibrium polymerization but an equilibrium polymerization by redistribution, not only a polyorganosiloxane having a star-shaped chemical structure with only one branch in the molecular chain but also many branches in the molecular chain. This is because the organopolysiloxane and the straight-chain organopolysiloxane are by-produced. Here, in the polymerization reaction, the conversion of the organocyclosiloxane of the component (C) is usually tracked by an analyzer such as gas chromatography, and when a certain value is reached, the polymerization is carried out by adding the component (D). It is preferred to stop the reaction. The preferred conversion is 95% or less to suppress the side reaction. The conversion is preferably from 70 to 95%, more preferably from 80 to 95%, from the viewpoint of the yield of the obtained organopolysiloxane. On the other hand, the molecular weight of the obtained organopolysiloxane is determined by the ratio of the component (C) that undergoes a polymerization reaction to the total weight of the components (A) and (B).

The acid or the functional group-bonded chlorosilane as the component (D) functions as a neutralizing agent for stopping the polymerization reaction in the production method of the present invention. Such a component (D) may be any component as long as it reacts with an alkali metal silanolate to form a stable alkali metal salt. Mineral acids such as carbonic acid, hydrochloric acid and sulfuric acid; acetic acid, propionic acid and acrylic acid Acids such as carboxylic acids,
Dimethylchlorosilane, dimethylphenylchlorosilane, or dimethylvinylchlorosilane. In the production method of the present invention, when the polymerization reaction is stopped by an acid such as carbonic acid, mineral acid, or carboxylic acid, the molecular chain terminal of the obtained organopolysiloxane becomes silanol, while
When the polymerization reaction is stopped by chlorosilane, the terminal of the molecular chain of the obtained organopolysiloxane becomes a siloxy group obtained by removing a chlorine atom from chlorosilane used. Therefore, the molecular chain terminal of the organopolysiloxane of the present invention can be selected by the component (D). Further, by adding various chlorosilanes to the organopolysiloxane of the present invention having a silanol group at the molecular chain terminal obtained by terminating the polymerization reaction with an acid, the organopolysiloxane of the present invention is obtained by a dehydrochlorination reaction. A functional group can also be introduced at the end of the molecular chain. In this case, it is recommended to use a hydrochloric acid scavenger such as an amine. Further, various functional groups can also be introduced by reacting the silanol-terminated organopolysiloxane with silazanes, silylamides, or alkoxysilanes. Further, in the presence of a platinum-based catalyst, an aliphatic unsaturated hydrocarbon having various functional groups is added to the organopolysiloxane of the present invention having a silicon-bonded hydrogen atom at the molecular chain terminal obtained using dimethylchlorosilane, By performing an addition reaction by a hydrosilylation reaction, organopolysiloxanes having various organic functional groups can be obtained.

According to the production method of the present invention, an organopolysiloxane having a narrow molecular weight distribution of the obtained organopolysiloxane can be obtained.

[Example] The present invention will be described using an example. In the examples, "Me"
Represents a methyl group, and “Vi” represents a vinyl group.

Example 1 In a four-necked flask equipped with a stirrer, 10.89 g of tetrakis (dimethylsiloxy) silane (33.12 mmol, Vi
Me ₂ Si (OSiMe ₂ ) ₃ Cl 50 g (145.72 mmol), toluene 100 ml, complex of platinum and tetramethyldivinyldisiloxane. The amount of platinum metal in the complex is tetrakis (dimethylsiloxy) silane and ViMe ₂ Si (OSiMe ₂ ) 40 ppm based on the total weight of ₃ Cl.投入 was added thereto, and the mixture was heated under reflux at the reflux temperature of toluene for 2 hours, and then the reaction mixture was analyzed by gas chromatography (hereinafter abbreviated as GLC) to find tetrakis (dimethylsiloxy).
The silane was found to be completely consumed. The reaction mixture was analyzed by infrared spectroscopy (hereinafter abbreviated as IR), and it was found that the characteristic absorption of silicon-bonded hydrogen atoms had disappeared. The reaction mixture was heated and excess ViMe ₂ Si (OSiMe ₂ ) ₃ Cl was distilled off under reduced pressure to obtain an organopolysiloxane (I) represented by the following formula.

In a four-necked flask with a stirrer, add 250 g of water and 2 ice
50 grams, 125 milliliters of diethyl ether and 15 grams of sodium bicarbonate were charged, and 53.9 grams of the obtained organopolysiloxane (I) was added while cooling and stirring.
A mixture of 1.68 mmol) and 50 ml of diethyl ether was added dropwise to carry out hydrolysis. After hydrolysis, the ether layer was separated, anhydrous sodium sulfate was added, and the ether layer was dried.The ether was distilled off under reduced pressure at room temperature.
An organopolysiloxane (II) represented by the following formula was obtained.

After a part of the obtained organopolysiloxane (II) was sampled and silylated with tetramethyldisilazane,
The reaction mixture was heated and excess tetramethyldisilazane was distilled off under reduced pressure. The amount of silicon-bonded hydrogen atoms in the product was determined by iodometry to be 0.214% by weight.
(Calculated value: 0.215% by weight).

A four-necked flask equipped with a stirrer, charged with 5 g (3.07 mmol) of organopolysiloxane (II) and 0.12 mmol of n-butyllithium in n-hexane, and a polymerization catalyst in which 4% of all silanol groups were lithiated A mixture was obtained. To this, 17.07 g (76.73 mmol) of hexamethylcyclotrisiloxane and 17.07 g of tetrahydrofuran were added, and a polymerization reaction was carried out for 7 hours under a nitrogen atmosphere. When the conversion was 79% by GLC, 2.24 g (22.10 mmol) of triethylamine and 1.39 g (14.74 mmol) of dimethylchlorosilane were sequentially added to terminate the polymerization reaction. After stirring the reaction mixture at room temperature for 1 hour, filtration was performed, and the filtrate was heated to remove unreacted raw materials under reduced pressure. The obtained product was determined to be an organopolysiloxane represented by the following average formula from the determination of silicon-bonded hydrogen atoms by GPC, nuclear magnetic resonance separation, IR, and iodometry.

The number average molecular weight of the obtained organopolysiloxane was 6335 (calculated value 6269) in terms of polymethylsiloxane, and the degree of dispersion was
1.26, silicon-bonded hydrogen atom 0.062% by weight (calculated value 0.0
64% by weight).

Example 2 In a four-necked flask equipped with a stirrer, 10.87 g (40.48 mmol) of methyltris (dimethylsiloxy) silane, 50 g (145.72 mmol) of ViMe ₂ Si (OSiMe ₂ ) ₃ Cl, 100 ml of toluene, platinum and tetramethyldivinyl Complex with disiloxane: The amount of platinum metal in the complex is methyltris (dimethylsiloxy) silane and ViMe ₂ Si (O
It is 20 ppm based on the total amount of SiMe ₂ ) ₃ Cl. ｝
After heating to the reflux temperature of toluene and heating to reflux for 2 hours, the reaction mixture was analyzed by GLC, and it was found that methyltris (dimethylsiloxy) silane was completely consumed. In addition, IR analysis of the reaction mixture showed that the characteristic absorption of silicon-bonded hydrogen atoms had disappeared.
The reaction mixture is heated and the excess ViMe ₂ Si (OSiMe
_{2) 3} was distilled off to Cl, to give the organopolysiloxane (III) represented by the following formula.

In a four-necked flask with a stirrer, add 250 g of water and 2 ice
50 g, 125 ml of diethyl ether and 13.3 g of sodium bicarbonate were added, and a mixture of 51.5 g (39.68 mmol) of the obtained organopolysiloxane (III) and 50 ml of diethyl ether was added dropwise while cooling and stirring, followed by hydrolysis. Was done. After the hydrolysis, the ether layer was separated, anhydrous sodium sulfate was added, and the ether layer was dried. The ether was distilled off at room temperature under reduced pressure to remove the organopolysiloxane (IV) represented by the following formula. Obtained.

After a part of the organopolysiloxane (IV) was sampled and silylated with tetramethyldisilazane, the reaction mixture was heated and excess tetramethyldisilazane was distilled off under reduced pressure. The silicon-bonded hydrogen atoms of the product were determined by iodometry to be 0.206% by weight (calculated 0.215%).
Wt%).

Into a four-necked flask equipped with a stirrer, 10 g (8.05 mmol) of organopolysiloxane (IV) and 0.32 mmol of an n-hexane solution of n-butyllithium were charged, and polymerization in which 4% of all silanol groups were lithiated. A catalyst mixture was obtained. 33.58 g (150.95 mmol) of hexamethylcyclotrisiloxane and 33.58 g of tetrahydrofuran were added thereto, and the mixture was reacted under a nitrogen atmosphere for 4.5 hours. GLC
When the conversion reached 79.9%, 4.40 g (43.47 mmol) of triethylamine and 2.74 g (28.98 mmol) of dimethylchlorosilane were sequentially added to stop the polymerization reaction. After stirring for 1 hour at room temperature, the reaction mixture was filtered, the filtrate was heated, and unreacted raw materials were distilled off under reduced pressure. The obtained organopolysiloxane was confirmed to be an organopolysiloxane represented by the following average formula from the determination of silicon-bonded hydrogen atoms by GPC, nuclear magnetic resonance analysis, IR, and iodometry.

This organopolysiloxane had a number average molecular weight in terms of polydimethylsiloxane of 5526 (calculated value of 4754) and a dispersity of 1.
23, silicon-bonded hydrogen atoms 0.064% by weight (calculated value 0.064
Wt%).

[Effect of the Invention] The organopolysiloxane of the present invention is novel, and the production method of the present invention is characterized in that such a novel organopolysiloxane can be easily produced.

Claims (2)

(57) [Claims] (1) a general formula: (Wherein, R ¹ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, R ² is an alkylene group having 2 or more carbon atoms, and R ³ is the same or different monovalent hydrocarbon group) A is a hydrogen atom, dimethylsilyl group, dimethylvinylsilyl group, dimethyl (γ-acryloxypropyl) silyl group, dimethyl (γ-glycidoxypropyl)
Silyl group or dimethyl (γ-mercaptopropyl)
A is a silyl group, a is 0 or 1, and m is an integer of 3 or more. ) An organopolysiloxane represented by the formula: (A) General formula: In the formula, R ¹ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, R ² is an alkylene group having 2 or more carbon atoms, and B is an alkali metal or hydrogen atom ( However, at least one of B is an alkali metal.)
And a is 0 or 1, and n is an integer of 0 or more. Using an alkali metal salt of an organopolysiloxane represented by 重合 as a polymerization catalyst, (B) a general formula: (Wherein, R ¹ is a same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, R ² is an alkylene group having 2 or more carbon atoms, a is 0 or 1, n is an integer of 0 or more.) In the presence or absence of an organopolysiloxane represented by the following formula (C): (Wherein, R ³ is the same or different monovalent hydrocarbon group.) After the polymerization reaction of the organocyclosiloxane represented by the following formula (D), acid, dimethylchlorosilane, dimethylphenylchlorosilane, or dimethylvinylchlorosilane is used. The method for producing an organopolysiloxane according to claim 1, wherein the polymerization reaction is stopped.