JP2627769B2 - Method for producing chain polyorganosiloxane - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing a linear polyorganosiloxane having a uniform molecular weight, and more particularly, to a specific lithium-containing organosilicon reaction initiator and an alicyclic tertiary compound. The present invention relates to a method for producing a bifunctional linear polyorganosiloxane, wherein living anion ring-opening polymerization of a cyclic polydiorganosiloxane is carried out in the presence of an amine.

Further, the present invention relates to a method for producing a chain polyorganosiloxane having various terminal groups, characterized by reacting a halosilane compound with the bifunctional chain polyorganosiloxane obtained in this manner.

[Technical background of the invention and its problems]

A chain polydiorganosiloxane having reactivity at the terminal and having a uniform molecular weight can be reacted with an organic monomer or polymer to obtain a block copolymer or a graft copolymer having a uniform siloxane chain length. And, as a result, a polymer material having a controlled microdomain structure is obtained, and its unique properties, such as blood compatibility, physiological properties such as affinity for a selected range of cells, and adhesion to adhesive substances are obtained. Surface properties such as releasability can be utilized for various applications.

As a method for obtaining such a linear polysiloxane having a uniform molecular weight, living anionic polymerization of hexamethylcyclotrisiloxane using a monolithium compound such as butyllithium as a reaction initiator is known (H. Kazam
a, Y.Tezuka, K.Imai; Polymer Journal, Vol.19, No.9,10
91-1100 ((1987)).

However, when such a monolithium compound is used, one end of the polysiloxane chain is blocked with a nonfunctional hydrocarbon group such as a butyl group, so that the resulting polyorganosiloxane is monofunctional. Limited.

Diphenylsilanediol dilithium salt is known as a reaction initiator to obtain a linear polyorganosiloxane having functionalities at both ends (EEBostick; ACS Polymer)
Preprint, Vol. 10, No. 2, pp. 877 ((1969)). But,
This reaction initiator, even using a solvent such as tetrahydrofuran, hexamethylphosphoric triamide, amines,
Poor solubility in hexaalkylcyclotrisiloxanes such as hexamethylcyclotrisiloxane. Therefore, it is difficult to quickly initiate the reaction, and the molecular weight distribution of the obtained chain polyorganosiloxane is not sufficiently satisfactory.

Another method for obtaining a polysiloxane having both ends functionalized with a uniform molecular weight is the presence of a biscatechol organosiliconate or lithium compound having water as a reaction initiator and having a quaternary ammonium structure in an organic group bonded to a silicon atom. A method of ring-opening polymerization of hexamethylcyclotrisiloxane is known below (CLLee et al .; Journal of P.
olymer Science, Polymer Chemistry, Vol. 14, No. 3, No. 729
-742 (1976) and 743-758 (1976).

However, in such a method, a polysiloxane having silanol groups at both ends is obtained, and when the polymer is reacted with dimethylchlorosilane to introduce a Si-H bond into the polymer end, hydrogen chloride is by-produced. , The catalytic action of which hydrolyzes the Si-H bond to produce Si
Polysiloxane having -H bond cannot be obtained.

Further, by performing ring-opening polymerization of hexamethylcyclotrisiloxane using an acetal-type lithium compound as a reaction initiator, a polysiloxane having a lithiumoxy group at one end having a uniform molecular weight and a functional group at the other end is obtained. A method is also known in which this is coupled with dimethyldichlorosilane to obtain a polysiloxane having functional groups at both ends and having a uniform molecular weight (P.
M. Lefebvre et al .; Macromolecules, Vol. 10, No. 4, 871-8
72 (1977)).

However, in this method, the reaction steps are complicated, and
The disadvantage is that the terminal functional groups are limited to hydroxy hydrocarbon groups or groups derived therefrom.

The present inventors have previously carried out ring-opening polymerization of hexaalkylcyclotrisiloxane using a dilithium salt of bis (hydroxydialkylsilylphenyl) ether as a reaction initiator, thereby having functionalities at both ends, and Having a bis (silphenylene) ether bond in the molecular chain,
It has been found that chain polyorganosiloxanes having a uniform siloxane chain length can be obtained (Japanese Patent Application No. 63-63100).

However, in this reaction system, when observing the molecular weight distribution of the obtained linear polyorganosiloxane by gel permeation chromatography (GPC), it is still insufficient to obtain a polymer having a highly uniform molecular weight with good reproducibility. Met. The reason is presumed to be that the dispersibility of the reaction initiator in the reaction system is not sufficient. Therefore, when using a chain polyorganosiloxane as a raw material of a copolymer that requires a highly strict microdomain structure, when uniformity of molecular weight is highly required, when starting the reaction, Great care must be taken to quickly disperse the reaction initiator in the reaction system.

[Object of the invention]

An object of the present invention is to obtain a bifunctional linear polyorganosiloxane having functionalities at both ends and having a highly uniform molecular weight with good reproducibility.

Another object of the present invention is to react the thus obtained chain polyorganosiloxane with halosilanes to have any number and kinds of functional groups at both ends or to have no functional groups at all. To obtain a linear polyorganosiloxane having a highly uniform molecular weight.

[Configuration of the invention]

The present inventors have conducted studies to find a suitable initiator system for the above purpose, and as a result, a lithium salt of a bissilanol compound having a bisphenylene ether chain between two silicon atoms was used as an initiator. It has been found that the object of the present invention can be achieved by using it and coexisting with an alicyclic tertiary amine during the polymerization, and the present invention has been completed based on the findings.

 That is, the gist of the present invention is as follows.

(1) General formula: LiO (R ¹ ) ₂ SiC ₆ H ₄ OC ₆ H ₄ Si (R ¹ ) ₂ OLi (wherein R ¹ may be the same or different, and represents an alkyl group). In the presence of a lithium-containing organosilicon compound and an alicyclic tertiary amine represented by the general formula: [(R ² ) ₂ SiO] ₃ , wherein R ² may be the same or different, A process for producing a chain polyorganosiloxane having a bisphenylene ether structure, characterized in that a hexaalkylcyclotrisiloxane represented by the following formula:

(2) General formula: LiO (R ¹ ) ₂ SiC ₆ H ₄ OC ₆ H ₄ Si (R ¹ ) ₂ OLi (wherein R ¹ may be the same or different, and represents an alkyl group). In the presence of a lithium-containing organosilicon compound and an alicyclic tertiary amine represented by the general formula: [(R ² ) ₂ SiO] ₃ , wherein R ² may be the same or different, Ring-opening polymerization of a hexaalkylcyclotrisiloxane represented by the general formula (R ³ ) ₃ SiX
(Wherein, R ³ may be the same or different and each represents a hydrogen atom, a halogen atom, a monovalent substituted or unsubstituted hydrocarbon group, an alkoxy group, an acyloxy group, or a ketoximato group, and X represents a halogen atom A process for producing a chain polyorganosiloxane having a bisphenylene ether structure, characterized by reacting a halosilane compound represented by the following formula:

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

(Lithium-containing organosilicon compound) The lithium-containing organosilicon compound used as a reaction initiator in the present invention has a general formula: LiO (R ¹ ) ₂ SiC ₆ H ₄ OC ₆ H ₄ Si (R ¹ ) OLi (wherein, R ¹ is as described above). Examples of R ¹ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and the like, which may be the same or different from each other, but the raw materials are easily obtained, the synthesis is easy, and A methyl group is preferred because it has excellent solubility in hexaalkylcyclotrisiloxane and gives a linear polyorganosiloxane having a uniform molecular weight distribution. The relative position of the bond between the silicon atom and the oxygen atom of the two phenylene groups can be arbitrarily selected, but the para position is preferred because the synthesis is easy.

Such lithium-containing organosilicon compounds include:
Bis [p- (hydroxydimethylsilyl) phenyl] ether dilithium salt, bis [p- (hydroxydiethylsilyl) phenyl] ether dilithium salt, bis [p- (hydroxydipropylsilyl) phenyl] ether dilithium salt, bis Examples thereof include [p- (hydroxymethylbutylsilyl) phenyl] ether dilithium salt and bis [m-hydroxydimethylsilyl) phenyl] ether dilithium salt.

Such a lithium-containing organosilicon compound is, for example, bis [p- (hydroxydimethylsilyl) phenyl]
Synthesis by dissolving a corresponding disilanol compound such as ether in an organic solvent such as tetrahydrofuran, and reacting with a hydrocarbon lithium compound such as n-butyllithium while cooling with ice in the absence of moisture. Can be. The amount of the lithium hydrocarbon compound is preferably at least equimolar to that of the disilanol compound, and it is preferable that the amount of the hydrocarbon lithium compound be in excess of 10 to 20 mol% in order to promote the reaction. After completion of the reaction, the organic solvent is removed by distillation under reduced pressure to obtain a lithium-containing organosilicon compound as a white solid.

Dilithium salts other than those represented by the above formula, for example, diphenylsilanediol dilithium salt and 1,4-bis (hydroxymethylsilyl) benzene dilithium salt are used in combination with an alicyclic tertiary amine as a reaction initiator. However, it does not give a polymer having a uniform molecular weight.

(Alicyclic Tertiary Amine) The alicyclic tertiary amine used in the present invention reproducibly produces a polymer having a highly uniform molecular weight in cooperation with the reaction initiator comprising the lithium-containing organosilicon compound. Shows effective work to get good. Although the details of the reason are not necessarily clear, it is presumed that the alicyclic tertiary amine increases the dispersion rate of the reaction initiator in the reaction system and facilitates the control of the ring-opening polymerization reaction. You.

Such alicyclic tertiary amines include N-methylpyrrolidine, N-ethylpyrrolidine, N-methylpiperidine and the like.

The amount of the alicyclic tertiary amine to be used is preferably more than 10 times mol, more preferably 15 to 40 times mol, of the lithium-containing organosilicon compound as the reaction initiator.
If the molar ratio is less than 10 times, the reproducibility is somewhat insufficient to obtain a polymer having a highly uniform molecular weight. There is no upper limit to the amount of the alicyclic tertiary amine used, but from the standpoint of isolation, purification and economy of the obtained polymer, it is suitably up to about 40 moles.

(Hexaalkylcyclotrisiloxane) The hexaalkylcyclotrisiloxane used as a polymerization raw material in the present invention has a general formula: [(R ² ) ₂ SiO] ₃ (where R ² is as described above)
Is represented by Examples of R ² include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group and a dodecyl group, which may be the same or different from each other. A methyl group is preferred in view of the ease of polymerization according to the invention and the heat resistance and interfacial properties of the resulting linear polyorganosiloxane.

Examples of such hexaalkylcyclotrisiloxane include hexamethylcyclotrisiloxane, hexaethylcyclotrisiloxane, 1,3,5-trimethyl-1,3,5-
Examples are tripropylcyclotrisiloxane and the like.

(Ring-Opening Polymerization) The ring-opening polymerization reaction is carried out, for example, by adding an alicyclic tertiary amine and a polymerization raw material to a reaction initiator suspended in an anhydrous organic solvent in an inert gas stream in which moisture is blocked. And at a temperature from room temperature to a temperature near the boiling point of the organic solvent.

After the polymerization, if the organic solvent is removed under reduced pressure, a bifunctional linear polyorganosiloxane in which lithiumoxy groups are bonded to silicon atoms at both ends is obtained. Tetrahydrofuran or the like can be used as the organic solvent. n
Hydrocarbon solvents such as -hexane are not preferred because the reaction initiator cannot be sufficiently dispersed.

(Halosilane compound) Further, after the polymerization reaction is completed, the compound represented by the general formula (R ³ ) ₃ SiX
(Wherein R ³ and X are as described above), whereby the terminal functional group can be replaced with any other group. The reaction can be performed by dropping halosilane into the organic solvent solution after the completion of the polymerization reaction. The reaction may be carried out at room temperature or with some heating or cooling.

Examples of X in the halosilane compound include a chlorine atom, a bromine atom and an iodine atom, but a chlorine atom is preferred because of easy handling. The R ³ is addition to the aforementioned X; hydrogen atom; a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an alkyl group such as hexyl group; beta-phenylethyl group; an alkenyl group such as vinyl group aralkyl groups such as β-phenylpropyl group; aryl groups such as phenyl group; substituted hydrocarbon groups such as chloromethyl group, chloropropyl group, trifluoropropyl group, and cyanoethyl group; such as methoxy group and ethoxy group Examples are an alkoxy group; an acyloxy group such as an acetoxy group and a benzoyloxy group; and a ketoximato group such as an acetone oximato group and a butanone oximato group, which may be the same or different.

As such halosilane compounds, silicon tetrachloride,
When a tetrafunctional silane such as chlorotrimethoxysilane or chlorotriethoxysilane is used, three functional groups are provided at both ends of the linear polysiloxane.

The use of trifunctional silanes, such as methyltrichlorosilane, phenyltrichlorosilane, methylchlorodimethoxysilane, methylchlorodiethoxysilane, imparts two functionalities to each end of the polysiloxane chain.

When a bifunctional silane such as dimethyldichlorosilane is used, the functional groups at both ends of the polysiloxane become chlorine atoms, and a bifunctional linear polysiloxane is obtained. When dimethylchlorosilane is used, a hydrogen atom is used, and when dimethylvinylchlorosilane is used, a vinyl group becomes a terminal functional group of the chain polysiloxane.

On the other hand, when a monofunctional silane in which three monovalent hydrocarbon groups not containing an aliphatic unsaturated bond are bonded to a silicon atom, such as trimethylchlorosilane and dimethylphenylchlorosilane, is used, a stable, non-functional silane is obtained. A chain polyorganosiloxane having a uniform molecular weight is obtained.

(Chain Polyorganosiloxane) As described above, ring-opening polymerization of hexaalkylcyclotrisiloxane in the presence of an alicyclic tertiary amine using the lithium compound used in the present invention as a reaction initiator is performed. By further reacting with a halosilane compound, a chain polyorganosiloxane having the following characteristics can be obtained easily and with good reproducibility.

(1) The molecular weight distribution is extremely narrow and the molecular weights are uniform.

(2) One or more functional groups are present at both ends. Alternatively, a chemically stable compound having no functional group can be synthesized.

(3) One bis (silphenylene) ether bond exists in the molecule.

〔The invention's effect〕

According to the present invention, having a functional group at both ends of the siloxane chain,
A chain polyorganosiloxane having a uniform molecular weight can be obtained easily and with good reproducibility. By reacting the functional groups at both ends with a halosilane compound, the number and type of the functional groups can be arbitrarily changed or the functional groups can be eliminated altogether.

The chain polyorganosiloxane obtained according to the present invention utilizes a uniform siloxane chain length and the presence of functional groups at both ends to synthesize a copolymer having a uniform siloxane segment length. Useful as a raw material for

The chain polyorganosiloxane obtained by the present invention, which has no functionalities at both terminals, has a uniform molecular weight, does not contain low-boiling substances, and is chemically stable.
In addition, the presence of the bis (silphenylene) ether bond improves the heat resistance and physical properties of the polymer. Therefore, it is suitable as an insulating material for applications in which the presence of low-boiling substances is not preferable, or applications requiring heat resistance and the like.

〔Example〕

Hereinafter, the present invention will be described with reference examples, examples, and comparative examples, but the present invention is not limited to only these examples. In these examples, all parts are by weight unless otherwise specified.

Reference Example 1 20 parts of bis [p- (hydroxydimethylsilyl) phenyl] ether was charged into a water-cooled jacket, a stirrer, a three-way cock and a reaction vessel provided with a dropping port, degassed and dry nitrogen was introduced. 710 parts of dry tetrahydrofuran was added and uniformly dissolved.

While cooling the reaction vessel with water, 68 parts of an n-hexane solution containing 8.9 parts of n-butyllithium was slowly added dropwise to carry out the reaction.
Time went. After completion of the reaction, tetrahydrofuran was distilled off under reduced pressure, the resulting salt was repeatedly decanted with dry n-hexane in a nitrogen stream, and then the solvent was volatilized to obtain bis [p- (hydroxydimethylsilyl) phenyl] as a white solid. 17.6 times of ether dilithium salt was obtained.
The yield was 85% of theory.

Reference Example 2 20 parts of diphenylsilanediol was charged into a reaction vessel, dried nitrogen gas was introduced, and 44.4 parts of dry tetrahydrofuran was added to uniformly dissolve.

While cooling with water, 93 parts of an n-hexane solution containing 13.1 parts of n-butyllithium was slowly added dropwise. Two hours later, tetrahydrofuran was distilled off under reduced pressure, and a diphenylsilanediol dilithium salt as a white solid was obtained in the same manner as in Reference Example 1.

Reference Example 3 An n-hexane solution containing 17.5 parts of p-bis (hydroxydimethylsilyl) benzene in a reaction vessel and 533 parts of dry tetrahydrofuran and 10.9 parts of n-butylium was used.
A white solid p-bis (hydroxydimethylsilyl) benzene dilithium salt was obtained in the same manner as in Reference Example 2 except that 83 parts were used.

Example 1 After degassing a reaction vessel and purging with nitrogen gas, 62 parts of dry tetrahydrofuran, 76.2 parts of N-methylpyrrolidine,
And the amount of hexamethylcyclotrisiloxane shown in Table 1 was charged and stirred to dissolve uniformly.

Next, the amount of bis [p- (hydroxydimethylsilyl) phenyl] ether dilithium salt synthesized in Reference Example 1 shown in Table 1 was previously dispersed in the amount of dry tetrahydrofuran shown in Table 1 by applying ultrasonic waves. The resulting dispersion was added, and the mixture was stirred while maintaining the temperature at 21 ° C., thereby performing ring-opening polymerization of hexamethylcyclotrisiloxane. After the polymerization was carried out for 3 hours, the amount of dimethylchlorosilane shown in Table 1 was added and the mixture was stirred to stop the polymerization. The remaining portion was repeatedly washed with methanol, dissolved in benzene, and freeze-dried to obtain a colorless, transparent and viscous polymer.

The yield and yield of the obtained polymer were as shown in Table 1.

For these polymers, gel permeation chromatography (GPC) using RI and UV as parameters was measured by monitoring with a differential refractometer and an ultraviolet spectrophotometer using tetrahydrofuran as a carrier. Table 1 shows the number average molecular weight obtained by GPC together with the calculated value obtained from the raw material mixing ratio.

In addition, IR and ¹ H-NMR of the obtained polymer were measured. The assignment of the characteristic spectrum is as shown in Table 2.

FIG. 1 shows an IR chart of the polymer obtained in Example 1.
GPC charts of the polymer obtained in Example 2 by RI and UV are shown in FIGS. 2 and 3, and a chart of ¹ H-NMR is shown in FIG. As is clear from the GPC chart, the molecular weight distribution of the obtained polymer is extremely narrow, and the molecular weights are uniform.

Examples 4 to 6 The amounts of hexamethylcyclotrisiloxane, bis [p- (hydroxydimethylsilyl) phenyl] ether dilithium salt and the dispersing agent tetrahydrofuran are as shown in Table 3, and the amounts of dimethylchlorosilane are shown in Table 3. Ring-opening polymerization of hexamethylcyclotrisiloxane and terminal vinylation were carried out in the same manner as in Examples 1 to 3, except that the indicated amount of dimethylvinylchlorosilane was used, and the reaction temperature was changed to 20 ° C. A coalescence was obtained.

The yield and yield of the obtained polymer were as shown in Table 3.

These polymers were monitored with a differential refractometer and an ultraviolet spectrophotometer using tetrahydrofuran as a carrier, and GPC with RI and UV as parameters.
Was measured. Table 3 shows the number average molecular weight obtained by GPC together with the calculated value obtained from the raw material mixing ratio.

In addition, IR and ¹ H-NMR of the obtained polymer were measured. The assignment of the characteristic spectrum is as shown in Table 4.

FIGS. 5 and 6 show the CPU chart of the polymer obtained in Example 4 by RI and UV.

The IR and ¹ H-NMR charts of the polymer obtained in Example 4 are shown in FIGS. 7 and 8.

Comparative Example 1 The same reaction vessel as used in Examples 1 to 3 was degassed and purged with nitrogen gas, and then 444 parts of tetrahydrofuran and 38.
4 parts of N-methylpyrrolidine and 50 parts of hexamethylcyclotrisiloxane were charged and stirred to dissolve uniformly. Then, a dispersion liquid in which 2.6 parts of the diphenylsilanediol / dilithium salt synthesized in Reference Example 2 were dispersed in 19.5 parts of tetrahydrofuran while applying ultrasonic waves in advance was added, and the mixture was stirred at 21 ° C. for 3 hours to obtain hexamethylcyclotriethyl. Ring opening polymerization of siloxane was performed.

After the polymerization, 10.7 parts of dimethylchlorosilane was added to obtain 41.2 parts of a colorless, transparent and viscous polymer in the same manner as in Example 1.

Monitor the obtained polymer with a differential refractometer.
GPC was measured. The GPC chart is shown in FIG. Ninth
As is clear from the figure, the molecular weights of the polymers were extremely irregular.

Comparative Example 2 The same reaction vessel as used in Examples 1 to 3 was degassed and purged with nitrogen gas, and then 311 parts of tetrahydrofuran and 38.
4 parts of N-methylpyrrolidine and 50 parts of hexamethylcyclotrisiloxane were charged and stirred to dissolve uniformly. Then, a dispersion prepared by dispersing 2.6 parts of the p-bis (hydroxydimethylsilyl) benzene dilithirim salt synthesized in Reference Example 3 in 64.8 parts of tetrahydrofuran was added, and the mixture was stirred at 21 ° C. for 3 hours to obtain hexamethylcyclohexane. Ring opening polymerization of trisiloxane was performed.

After the polymerization, 42.7 parts of dimethylchlorosilane was added to obtain 39.8 parts of a colorless, transparent and viscous polymer in the same manner as in Example 1.

Monitor the obtained polymer with a differential refractometer.
GPC was measured. The GPC chart is shown in FIG. Tenth
As is clear from the figure, the molecular weights of the polymers were extremely irregular.

[Brief description of the drawings]

FIG. 1 shows an IR chart of the polymer obtained in Example 1, and FIGS. 2 and 3 show a GPC chart of the polymer obtained in Example 2. FIG. 4 shows an NMR chart of the polymer obtained in Example 2. 5 and 6 show a GPC chart of the polymer obtained in Example 4, FIG. 7 shows an IR chart, and FIG. 8 shows an NMR chart. 9 and 10 show GPC charts of the polymers obtained in Comparative Examples 1 and 2, respectively.

Claims (2)

(57) [Claims] 1. A general formula: LiO (R ¹ ) ₂ SiC ₆ H ₄ OC ₆ H ₄ Si (R ¹ ) ₂ OLi (wherein R ¹ may be the same or different, and represents an alkyl group) ) In the presence of a lithium-containing organosilicon compound and an alicyclic tertiary amine represented by the general formula: [(R ² ) ₂ SiO] ₃ (wherein R ² may be the same or different. Wherein the hexaalkylcyclotrisiloxane represented by the formula (1) represents a ring-opening polymerization of a hexaalkylcyclotrisiloxane having a bisphenylene ether structure. 2. The general formula: LiO (R ¹ ) ₂ SiC ₆ H ₄ OC ₆ H ₄ Si (R ¹ ) ₂ OLi (wherein R ¹ may be the same or different and each represents an alkyl group. ) In the presence of a lithium-containing organosilicon compound and an alicyclic tertiary amine represented by the general formula: [(R ² ) ₂ SiO] ₃ (wherein R ² may be the same or different. , Which represents an alkyl group) after ring-opening polymerization of a hexaalkylcyclotrisiloxane represented by the general formula (R ³ ) ₃ Six
(Wherein, R ³ may be the same or different and each represents a hydrogen atom, a halogen atom, a monovalent substituted or unsubstituted hydrocarbon group, an alkoxy group, an acyloxy group, or a ketoximato group; A method for producing a chain polyorganosiloxane having a bisphenylene ether structure, characterized by reacting a halosilane compound represented by the following formula: