JP2001278980A - Method of producing branched polymer containing siloxane linkage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of effectively producing a branched polymer containing a siloxane linkage of highly branched structure having a silanol group or functional group at a molecular chain terminal. SOLUTION: The method of producing the branched polymer containing a siloxane linkage is characterized by ring-opening copolymerizing (B) a cyclic trisiloxane represented by general formula (B) and (C) a cyclic trisiloxane containing a silanol group represented by general formula (C) with (A) lithium silanolate or lithium siloxanolate as porimerization initiator, and thereafter terminating above porimerization with (D) an acid or a halogen atom-containing compound bound with silicon atom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a siloxane bond-containing branched polymer, and more particularly, to a method for efficiently producing a highly branched siloxane bond-containing polymer having a silanol group or a functional group at a molecular chain terminal. About the method.

[0002]

2. Description of the Related Art Various types of hyperbranched polymers typified by starburst dendrimers (dendritic polymers) are known. These hyperbranched polymers have a higher functional group density per molecular unit than linear or ordinary branched polymers, and have a feature that they have more space in their generations, that is, when the degree of polymerization increases, they have a space inside. Have. From these properties, surfactants, gelling agents,
Applications such as missile drugs and polymer absorbents are being considered.

Various methods have been proposed for producing a highly branched polymer having a siloxane bond. For example, JP-A-3-263431 discloses a condensation reaction between a SiCl group and a SiOH group, a hydrolysis reaction of a SiH group. A method of synthesizing a silicon-bonded hydrogen atom-functional polysiloxane dendrimer by repeating a multi-step reaction including a decomposition reaction has been proposed. Also, Organometallic has been proposed.
News, 40-42 (1993) discloses that a polyfunctional chlorosilane is reacted with 1,1,3,3-tetramethyldisiloxane in the presence of hydrochloric acid to convert a chlorine atom of a SiCl group into a dimethylsiloxy group, Methods for synthesizing atom-bonded hydrogen atom functional polysiloxane dendrimers have been proposed. Each of these synthesis methods is a multi-step reaction, and separation and purification are performed at each step, so that there is an advantage that a molecular weight distribution is narrow and a dendrimer with a clear structure is obtained, but a dendrimer of a desired generation is obtained. Must be repeated many times, the overall yield is low,
It was difficult to mass-produce industrially.

On the other hand, a highly branched polysilethylene having a silicon atom-bonded hydrogen atom function or a silicon atom-bonded vinyl group function in one step by an intermolecular hydrosilylation reaction of vinyl tris (dimethylsiloxy) silane or tris (vinyldimethylsiloxy) silane. The method for obtaining siloxane is described in J. I
norg. Organomet. Polym. 4 (1),
61-77 (1994). According to this method, although a molecular weight distribution is narrow and a dendrimer with a clear structure cannot be obtained, a silicon-functional hyperbranched polysilethylenesiloxane can be obtained in one step, and industrial mass production is possible. However, in the hyperbranched polysilethylene siloxane obtained by this method, the ratio of the polysiloxane structure to the ethylene structure is low, and the properties unique to polysiloxane cannot be imparted to the hyperbranched polymer. In addition, a highly branched siloxane bond-containing polymer having a silanol group or various functional organic groups at the molecular chain end could not be efficiently produced.

[0005]

The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention.
That is, an object of the present invention is to provide a method for efficiently producing a siloxane bond-containing branched polymer having a highly branched structure having a silanol group or a functional group at a molecular chain terminal.

[0006]

The process for producing a siloxane bond-containing branched polymer of the present invention comprises (A) using lithium silanolate or lithium siloxanolate as a polymerization initiator, and (B) a general formula:

Embedded image (Wherein R ¹ is the same or different, substituted or unsubstituted monovalent hydrocarbon group) and (C) a general formula:

Embedded image (Wherein, R ¹ is the same or different, substituted or unsubstituted monovalent hydrocarbon group, R ² is an oxy group, an alkylene group, or an alkyleneoxyalkylene group, and x is 1, 2, or 3 And n is an integer from 0 to 10.
However, when n is 0, R ² is an oxy group. ), The ring-opening copolymerization of the silanol group-containing cyclic trisiloxane, and then terminating the polymerization with (D) an acid or a compound containing a silicon-bonded halogen atom.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a siloxane bond-containing branched polymer of the present invention will be described in detail. The component (A), lithium silanolate or lithium siloxanolate, has a bond represented by Si-O-Li, and is known as a polymerization catalyst for cyclic trisiloxane. Examples of the lithium silanolate of the component (A) include lithium trimethylsilanolate, lithium triethylsilanolate, and lithium phenyldimethylsilanolate.
Illustrative are organopolysiloxanes having lithioxydiorganosiloxy groups blocked at one end of molecular chains and organopolysiloxanes having lithioxydiorganosiloxy groups blocked at both ends of molecular chains. Such a lithium silanolate or lithium siloxanolate is a silanol group-containing silane such as trimethylsilanol, triethylsilanol, or phenyldimethylsilanol, or an organosiloxane having a silanol group at one end of a molecular chain, or an organosiloxane having a silanol group at both ends of a molecular chain. A silanol group-containing siloxane and an alkyl lithium such as n-butyl lithium, methyl lithium, s-butyl lithium, t-butyl lithium,
Alternatively, it can be prepared by reacting a lithium compound such as aryl lithium such as phenyl lithium. In this reaction, when the silanol group-containing silane or silanol group-containing siloxane is used in excess, unreacted silane or siloxane remains,
These silanes or siloxanes act as polymerization degree regulators or polymerization accelerators for the siloxane bond-containing branched polymer in the production method of the present invention. For this reason, the molar ratio of lithium silanolate or lithium siloxanolate to silanol group-containing silane or silanol group-containing siloxane is 100: 0 to 0.01: 1.
00, preferably 0.5: 9
It is preferably in the range of 9.5 to 50:50.

The cyclic trisiloxane of the component (B) has the general formula:

Embedded image Indicated by R ¹ in the formula is the same or different, substituted or unsubstituted monovalent hydrocarbon group, and an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group; a vinyl group, an allyl group Alkenyl groups such as butenyl group; aryl groups such as phenyl group, tolyl group and xylyl group; aralkyl groups such as benzyl group and phenethyl group; halogens such as 3-chloropropyl group, 3,3,3-trifluoropropyl group and the like. An alkyl group is exemplified, preferably an alkyl group or an aryl group, more preferably a methyl group or a phenyl group, and particularly preferably a methyl group. The following compounds are exemplified as such a cyclic trisiloxane.

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The silanol group-containing cyclic trisiloxane (C) has the general formula:

Embedded imageIndicated by R in the formula¹Are the same or different substitutions
Or an unsubstituted monovalent hydrocarbon group,
Is exemplified. Also, R in the formula^TwoIs an oxy group, alkylene
Or an alkyleneoxyalkylene group;^Two
Examples of the alkylene group include an ethylene group, a propylene group,
Butylene and hexylene groups are exemplified;^TwoArchille
Propyleneoxypropyl
A len group is exemplified. Further, x in the formula is 1, 2, or
3. Further, n in the formula is an integer of 0 to 10, and
More preferably, it is an integer of 0 to 3. However, when n is 0,
R^Two Is an oxy group. Such silanol group-containing ring
The following compounds are examples of the linear trisiloxane.
It is.

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As a method for preparing the silanol group-containing cyclic siloxane as the component (C), for example, the alkenyl group-containing cyclic siloxane and the silicon-bonded hydrogen atom-containing hydrolyzable silane are subjected to a hydrosilylation reaction, and then the obtained hydrolyzable siloxane is reacted. A method of preparing by hydrolyzing a decomposable group-containing cyclic siloxane is exemplified.

In the manufacturing method of the present invention, first,
The component (A) is used as a polymerization initiator, and the component (B) and the component (C) are subjected to ring-opening copolymerization. In the production method of the present invention, the ratio between component (B) and component (C) is arbitrary,
If the ratio of the components is too large, the obtained siloxane bond-containing branched polymer tends to gel, so it is necessary to appropriately adjust the ratio. In the production method of the present invention, the use of an organic solvent is optional. The organic solvent is not particularly limited as long as it is aprotic, and examples thereof include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane and pentane; ethers such as tetrahydrofuran and diethyl ether; Ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate and butyl acetate; and dimethylformamide, dimethylsulfoxide and hexamethylphosphoric triamide.
In the production method of the present invention, two or more organic solvents may be used as a mixture. For example, when a low-polarity solvent such as toluene is used, the ring-opening of the components (B) and (C) is performed. In order to promote the polymerization, it is preferable to use a highly polar solvent such as dimethylformamide, dimethylsulfoxide, and hexamethylphosphoric triamide in combination.

In the production method of the present invention, the reaction temperature is preferably in the range of 0 to 100 ° C., since the rearrangement reaction of the siloxane bond may occur when the reaction temperature is high. Preferably it is in the range of 70 ° C. In the production method of the present invention, the component (B)
The progress of the ring-opening polymerization with the component (C) can be confirmed by following the amount of the component (B) or the component (C) reduced by gas chromatography or the like. The end point of the polymerization reaction can be a point in time when the reaction rate of the component (B) or the component (C) reaches a certain value. In general, the higher the conversion is, the higher the yield of the obtained siloxane bond-containing branched polymer is, but the possibility of rearrangement reaction of the siloxane bond is large, and the obtained siloxane bond-containing branched polymer is easily gelled. Tend. Therefore,
It is necessary to determine this reaction rate in consideration of the purity and yield of the objective siloxane bond-containing branched polymer. The optimum reaction rate depends on the type of the component (B) or the component (C),
Alternatively, since it depends on the molecular weight of the objective siloxane bond-containing branched polymer, it cannot be said unconditionally.
It is preferably in the range of 0 to 100%, and in particular, 7
Preferably it is in the range of 0-95%. Until this reaction rate is reached, it is necessary to continue the ring-opening polymerization of the components (B) and (C), and the polymerization time depends on the reaction temperature and the component (B).
Depending on the reactivity of the component (C), ring-opening polymerization can be performed at a low temperature in a relatively short time by using a raw material having a high reactivity.

In the production method of the present invention, the ring-opening polymerization of the components (B) and (C) is terminated by the acid (D) or the compound containing a silicon-bonded halogen atom. As the acid of the component (D), mineral acids such as aqueous carbon dioxide, hydrochloric acid, sulfuric acid, etc .;
Organic acids such as propionic acid and carboxylic acid are exemplified.
When an acid is used as the component (D), the acid is preferably a weak acid, since an excess acid may cause rearrangement of siloxane bonds in the obtained siloxane bond-containing branched polymer. , Hydrous carbon dioxide or acetic acid. When an acid is used as the component (D), a siloxane bond-containing branched polymer having a silanol group at a molecular chain terminal can be obtained.

The compound containing a silicon-bonded halogen atom as the component (D) includes diorganohydrogenhalosilanes such as dimethylchlorosilane, diethylchlorosilane, diphenylchlorosilane, and dimethylbromosilane; vinyldimethylchlorosilane, hexenyldimethylchlorosilane, and divinylsilane. Alkenyl group-containing halosilanes such as methylchlorosilane; acryloxy group-containing halosilanes such as acryloxypropyldimethylchlorosilane, acryloxyhexyldimethylchlorosilane, acryloxyethoxypropyldimethylchlorosilane and acryloxypropyldimethylbromosilane; methacryloxypropyldimethylchlorosilane, methacryloxyhexyl Dimethylchlorosilane, methacryloxyethoxypropyldimethylchlorosilane Methacryloxypropyl methacryloxy group-containing halosilane such as dimethyl bromo silane; 4
Halosilanes such as vinylphenyl group-containing halosilanes such as -vinylphenyldimethylchlorosilane, 4-vinylphenyldimethylbromosilane and 2-vinylphenyldimethylchlorosilane;

Embedded image A chlorosylethylene siloxane represented by the formula:

Embedded image And halosilyl group-containing siloxanes such as chlorosylethylenesiloxane. When a halosilane is used as the component (D), a siloxane bond-containing branched polymer having a functional group such as a silicon-bonded hydrogen atom, an alkenyl group, an acryloxy group, a methacryloxy group, or a vinylphenyl group at a molecular chain terminal is obtained. Can be When a halosilane is used as the component (D), it is preferable to add an organic amine compound, ammonia, or the like in order to capture hydrogen halide generated by hydrolysis of an excess halosilane.

The siloxane bond-containing branched polymer obtained by the production method of the present invention has a general formula:

Embedded image And a siloxane unit represented by the following formula:

Embedded image And a siloxane unit represented by the formula:

Embedded image A siloxane unit represented by the following, or a general formula:

Embedded image It has a silanol group or a functional group at the molecular chain end because it has a branched structure having a siloxane unit represented by, and should be used as a reactive diluent, a reaction accelerator, a modulus control agent, or an intermediate for modifying an organic resin. Can be. R ¹ in the formula is the same or different, substituted or unsubstituted monovalent hydrocarbon group, and the same groups as described above are exemplified. R ³ in the formula is an alkylene group or an alkyleneoxyalkylene group, and examples thereof include the same alkylene group or alkyleneoxyalkylene group as R ² . Further, the siloxane bond-containing branched polymer having a silanol group at the molecular chain terminal obtained by the production method of the present invention may be added to the above-mentioned halosilane or an alkenyl alcohol such as vinyldimethylacetoxysilane, hexenyldimethylacetoxysilane, or divinylmethylacetoxysilane. Siloxysilanes; acryloxyalkyl acyloxysilanes such as acryloxypropyldimethylacetoxysilane, acryloxyhexyldimethylacetoxysilane, acryloxyethoxypropyldimethylacetoxysilane; methacryloxypropyldimethylacetoxysilane, methacryloxyhexyldimethylacetoxysilane, methacryloxy Methacryloxyalkyl acyloxysilanes such as ethoxypropyldimethylacetoxysilane; 4-vinylphenyldimethyl Acetoxysilane, 2
-Vinyl phenyl acyloxy silane such as vinyl phenyl dimethyl acetoxy silane; further, by reacting a cyclic silylamine or the like, a silicon atom-bonded hydrogen atom, an alkenyl group, an acryloxy group, a methacryloxy group, a vinyl phenyl group, a vinyl phenyl group, A siloxane bond-containing branched polymer having a functional group such as a group can be obtained.

[0016]

EXAMPLES The method for producing a siloxane bond-containing branched polymer of the present invention will be described in detail with reference to examples.

Reference Example In a four-necked flask equipped with a stirrer, 15 g (58.1 mmol) of 1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane and 1,3-platinum of platinum were added. Divinyltetramethyldisiloxane complex (platinum metal is 5 ppm by weight based on the total amount of the reaction mixture)
) And heated to 90 ° C. Subsequently, 24.7 g (209.2 mmol) of dimethylacetoxysilane was added dropwise thereto, and the mixture was stirred at 90 to 100 ° C for 4 hours.
When the reaction mixture was analyzed by infrared absorption analysis (hereinafter, IR), it was confirmed that the peak of the vinyl group had almost disappeared. Next, low-boiling substances were distilled off from the reaction mixture by heating under reduced pressure to obtain 35 g of a liquid. This liquid was analyzed by IR and nuclear magnetic resonance analysis (hereinafter, NMR).

Embedded image Was found to be an acetoxy group-containing cyclic siloxane. The yield was 98.7%.

Next, in a four-necked flask equipped with a stirrer,
15.1 g (180.2 mmol) of sodium bicarbonate and 50 ml of water were added, and then a solution of 32 g (52.3 mmol) of the acetoxy group-containing cyclic siloxane and 50 ml of methyl isobutyl ketone was added thereto. Further, 1.58 g (15.6 mmol) of triethylamine was added, and the mixture was stirred at 30 ° C. for 2 hours. Thereafter, the mixture was allowed to stand and separated, and the lower layer was discarded. The upper layer was washed three times with water, and dried by adding sodium sulfate. Sodium sulfate was removed by filtration, and low-boiling substances were distilled off from the filtrate by heating under reduced pressure to give 23.8 g.
Was obtained as a viscous liquid. When this liquid was analyzed by IR and NMR, the formula:

Embedded image Was found to be a silanol group-containing cyclic siloxane. The yield was 93.7%.

Example 1 In a four-necked flask equipped with a stirrer, 2.27 g of dimethylpolysiloxane having a silanol group at both ends of a molecular chain represented by an average formula: HO {Si (CH ₃ ) ₂ O} _4.3 H ( 6.8
Mmol) and 0.054 mmol of n-butyllithium were added to prepare dimethylpolysiloxane in which a part of silanol groups was replaced by lithium silanolate groups. Then this has the formula:

Embedded image 28.6 g (386.3 mmol) of cyclic siloxane represented by the formula and 36.4 g of toluene were added, and the formula prepared in Reference Example:

Embedded image 5.5 g of a silanol group-containing cyclic siloxane represented by
(1.3 mmol), 8.5 g of acetonitrile and 2 g of dimethylformamide, and the mixture was stirred at 30 ° C. for 4.5 hours to carry out polymerization. Thereafter, the reaction mixture was analyzed by gas chromatography, and it was confirmed that the conversion of hexamethylcyclotrisiloxane was 80%. Next, the polymerization was terminated by adding 0.04 g of acetic acid to the reaction mixture. afterwards,
From the reaction mixture, low-boiling substances were distilled off by heating under reduced pressure, and 29.5 g of a by-produced trace of salts were filtered off.
Was obtained. When this polymer was analyzed by gel permeation chromatography, it was found that the number average molecular weight in terms of standard polystyrene was 1442 and the degree of dispersion was 2.05. Also, this polymer
^{As a} result of analysis by ²⁹ Si-NMR, the signal derived from the cyclotrisiloxane skeleton and the signal derived from the ethylenedimethylsilanol group of the silanol group-containing cyclic siloxane prepared in Reference Example completely disappeared.

Embedded image The signal of the siloxane unit represented by and the formula:

Embedded image The signal of the siloxane unit represented by and the formula:

Embedded image The signal of the siloxane unit represented by and the formula:

Embedded image Since the signal of the siloxane unit represented by was confirmed, it was confirmed that this polymer was a siloxane bond-containing branched polymer having a branched structure and having a molecular chain terminal blocked with a silanol group.

[0020]

The method for producing a siloxane bond-containing branched polymer of the present invention is characterized in that a highly branched siloxane bond-containing polymer having a silanol group or a functional group at a molecular chain terminal can be efficiently produced. There is.

[Brief description of the drawings]

FIG. 1 is a ²⁹ Si-nuclear magnetic resonance spectrum chart of a siloxane bond-containing branched polymer prepared in Example 1.

Claims (1)

[Claims] (1) Lithium silanolate or lithium siloxanolate is used as a polymerization initiator, and (B) a compound represented by the following general formula: (Wherein R ¹ is the same or different, substituted or unsubstituted monovalent hydrocarbon group) and (C) a general formula: (Wherein, R ¹ is the same or different, substituted or unsubstituted monovalent hydrocarbon group, R ² is an oxy group, an alkylene group, or an alkyleneoxyalkylene group, and x is 1, 2, or 3 And n is an integer from 0 to 10.
However, when n is 0, R ² is an oxy group. A) a ring-opening copolymer of a silanol group-containing cyclic trisiloxane represented by the formula (D), followed by terminating the polymerization with (D) an acid or a compound containing a silicon-bonded halogen atom. Manufacturing method.