JPH01272633A - Production of polysiloxane - Google Patents

Abstract

PURPOSE:To obtain the subject straight-chain polymer containing silanol groups at both terminals and having narrow molecular weight distribution and easily controllable molecular weight, by carrying out anionic polymerization of a cyclic polysiloxane in the presence of a specific amount of a Li-based catalyst using water as a polymerization initiator. CONSTITUTION:The objective polymer of formula II (n is 3-400) can be produced by the anionic polymerization of a cyclic polysiloxane of formula I [R<1> is methyl or phenyl; R<2> is methyl or CmH2m+1C2H4 (m is 1-10); p is 3, 4] (preferably hexamethylcyclotrisiloxane) in a polar solvent free from active hydrogen (preferably THF) in the presence of 0.1-10mol% (based on polymerization initiator) of a lithium-based catalyst (e.g., metallic lithium) using water as a polymerization initiator. The above reaction is preferably carried out by using a dried anhydrous raw materials in dried atmosphere at 15-25 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel method for producing a linear polysiloxane having silanol groups at both ends, whose molecular weight can be easily controlled and whose molecular weight distribution is small.

[Conventional technology]

Conventionally, in producing a linear polysiloxane having silanol groups at both ends, it has generally been synthesized by hydrolysis of organic dichlorosilane or an equilibration reaction between a cyclic polysiloxane and water. (Tokuko Sho 58-5928
(No. Publication) [Problems to be Solved by the Invention] However, polysiloxanes having silanol groups at both ends obtained by conventional production methods undergo an equilibration reaction under heating at 50 to 200°C, so they produce by-products. It contains more than ten percent of cyclic siloxane as a substance, and
It was difficult to control the molecular weight and the degree of dispersion was large. Therefore, when incorporated into synthetic resins for use in fields such as surface modification, it has been difficult to control the surface structure because the polysiloxane composition is non-uniform.

The object of the present invention is to provide a method for producing a polysiloxane compound having silanol groups at both ends, which has a low degree of dispersion and does not contain a cyclic oligomer, which is particularly excellent in overcoming all the problems of the conventional art as described above. This is what we provide.

[Means to solve problems]

In order to achieve the above object, the present inventors investigated the amount of steel and found that cyclic polysiloxane was anionically polymerized using water as an initiator in the presence of a lithium-based catalyst in an amount of 0.1 to 10 mol% based on the initiator. By this, it is possible to obtain a linear polysiloxane having silanol groups at both ends;
Moreover, the present invention was completed based on the knowledge that the molecular weight of the resulting linear polysiloxane is controllable and has a small degree of dispersion, which is equivalent to the conventional living polymerization method.

That is, in the present invention, water is used as an initiator, and 0.1
In the presence of ~10 mol% lithium-based catalyst, general formula (A)
By anionically polymerizing a cyclic polysiloxane represented by the general formula (B
) is a method for producing polysiloxane represented by

(However, R1 is a methyl group or phenyl group, R2 is a methyl group, phenyl group, or CrnF2m+tCtH4,X: (
m = 1 to 10), p is 3 or 4, and n is 3 to 400
It is. ] In the present invention, the cyclic polysoloxane represented by the general formula (A) (hereinafter abbreviated as "cyclic body") is hexamethylcyclotrisiloxane (hereinafter referred to as "D").
It is abbreviated as ), octamethylcyclotetrasiloxane (hereinafter abbreviated as "D4"), hexaphenylcyclotrisiloxane, octamethylcyclotetrasiloxane, tris(trifluoropropyl)trimethylcyclotrisiloxane and tetrakis(trifluoropropyl)tetra Methylcyclotetrasiloxane and the like can be mentioned, but among these, D4 is preferable, and among them, Mori is particularly preferable.

As the lithium-based catalyst, metal lithium, lithium hydride, buterlinium, lithium hydroxide, or a mixture of two or more of these can also be used.

Materials other than these lithium-based catalysts, such as other alkali metal-based compounds, cannot be used as catalysts because the yield of the desired polysiloxane of the general formula CB) is low.

The amount of the above lithium-based catalyst used is preferably 0.1 to 10 mol%, more preferably 0.1 to 2.0 mol%, based on water as a polymerization initiator. A range of 0.5 to 1.0 mol% is particularly preferred. Lower limit value 0
．． If it is less than 1 mol%, the weighting speed will be slow and the upper limit of 1
Even better results can be obtained even if more than 0 mol% of 5-w is used.

In the present invention, the polymerization degree of the linear polysiloxane having silanol groups at both ends of the general formula CB (hereinafter referred to as "double-terminated silanol-modified polysiloxane") is determined by the molar ratio of the initiator to the cyclic body. The molar ratio of initiator/cyclic body is preferably in the range of 0.01 to 1, although it can be adjusted freely. Even if the molar ratio is outside this range, it is not impossible to produce, and for example, it is not the purpose of the present invention, but if it is desired to obtain a product in which the value of n in the general formula (B) is less than 3, the molar It is possible to set the ratio to a value similar to 1, but in this case, it is difficult to control the molecular weight distribution, and it is difficult to obtain a preferable molecular weight distribution. Further, when the molar ratio 'to is set to less than 01, it becomes difficult to control the molecular weight, but this is presumed to be because the concentration of the catalyst in the reaction system decreases relatively and the polymerization rate slows down.

In addition, as the polar solvent having no active hydrogen used in the polymerization of the present invention, tetrahydrofuran, 1,4-dioxane, ethylene/licol dimethyl ether, diethylene glycol dimethyl ether, dimethyl formamide, and dimethyl sulfoxide are suitable, and these two
Mixtures of more than one species can also be used. Among these, tetrahydrofuran is particularly preferred. A solvent containing active hydrogen will inhibit the polymerization reaction, and a nonpolar solvent will hardly allow the polymerization reaction to occur at an appropriate level.

Next, other conditions related to the polymerization reaction will be explained.

First, it is important that the raw materials used in the reaction be dried to remove any moisture contained therein, and if this condition is not met, it will be difficult to obtain a product containing the desired molecular weight. It is desirable to seal the system with dry nitrogen or dry argon to create a dry atmosphere.

The reaction temperature is preferably in the range of 0 to 30°C, especially 15 to 25°C.
°C is preferred. Below 0°C, the polymerization rate slows down,
30°b The molecular weight distribution of the ranol-modified polysiloxane is wide and easy to increase.

The reaction time varies depending on the reaction temperature, but it is preferable to stop the polymerization reaction when about 95% of the
~20°C, the range is approximately 10-20 hours.

If the polymerization is carried out for a longer time than this, the molecular weight distribution will become broader, which is not preferable.

To completely stop the polymerization reaction, a terminating agent such as acetic acid or carbon dioxide gas is used. The amount of the terminator used is equal to or greater than the amount of the catalyst used above.

The temperature at the time of stopping the reaction may be maintained at the same polymerization temperature, and a reaction time of about 30 minutes to 1 hour is sufficient.

As described above, a polysiloxane modified with silanol at both terminals and having a small molecular weight distribution with a dispersity of 1.1 to 1.2 can be obtained with a desired molecular weight.

By reacting the polysiloxane modified with silanol at both ends obtained in this manner with various chlorosilanes in the presence of an organic base, various functional groups other than silanol groups can be introduced in place of the silanol groups. can. In this case, the organic base is preferably a tertiary amine such as triethylamine or tributylamine, or pyridine, and the amount used is 1.1 to 1.5 in equivalent ratio to the chlorosilane used.
Double molar ratio is preferred. The equivalent ratio of chlorosilane to one molecule of polysiloxane modified with silanol at both ends is 2.1 to 2.
．． The 2x Monope reaction solvent may be hexane, various ethers, or no solvent, as long as the reaction temperature is 20 to 40°C and the reaction time is 3 to 5 hours.

Furthermore, a functional group other than the silanol group can be introduced in place of the silanol group by stopping the combined reaction of polysiloxane modified with silanol at both ends with various chlorosilanes in the presence of an organic base. The reaction conditions at this time may be the same as those for the reaction of the polysiloxane modified with silanol at both ends and the chlorosilane, except that the solvent and reaction temperature are the same as the conditions for anionic polymerization.

It has become possible to easily and inexpensively produce polysiloxanes that have reactive functional groups at both ends and have a low degree of dispersion.

Various linear polysiloxanes having reactive functional groups thus obtained are used as raw materials for block polymers as teleclick polymers. By adding these block polymers to a base polymer, the surface can be modified in various properties such as water repellency and low friction, as a result of the interfacial properties of silicone. Further, functions such as gas permeability and antithrombotic properties can be imparted.

〔Example〕

The present invention will be explained in more detail below with reference to Examples and Reference Examples, but the present invention is not limited to these Examples in any way.

Example 1 Production of a linear polysiloxane having silanol groups at both ends.

D, 150F (0,675 mol), 200 anhydrous tetrahydrofuran, 11 water, 1.89 (0.1 mol) were charged into a flask under a stream of N, and 0.015 y of lithium hydroxide (
6.25×10 mol) and polymerized at 20°C for 17 hours. Next, acetic acid o and osH were added, and the reaction was stopped by stirring for about 30 minutes.

The generated lithium acetate was completely removed by washing with water, and the organic layer was dried using anhydrous sodium sulfate. Next, after removing the solvent using an evaporator, the oligomer is distilled under reduced pressure. The residue was distilled off to obtain the desired linear polysiloxane 143y'i modified with silanol at both ends.

Molecular weight of the obtained polysiloxane (based on gel permeation chromatography).

Polystyrene equivalent molecular weight. ) and OH group analysis results are shown below, and it can be seen that the molecular weight is controlled and the degree of dispersion is small.

Mw: 18 0
0Mn: 1500 (calculated value -1500) Dispersity (Mw/Mn): 1-20H group
: 2.24″M% (calculated value = 2.24) Example 2 Production of a linear polysiloxane having silanol groups at both ends.

D3120y (0.54 mol), anhydrous tetrahydrofuran 200 ml, water 0.054f (0,003 mol)
k into a flask under a Nt gas flow, add 20 μlk of butyllithium hexane solution (1.6 mol/l),
After reacting at 0°C for 15 hours, 71v of acetic acid was added to stop the reaction.

All post-treatments were carried out in the same manner as in Example 1 to obtain linear polysiloxane 114y having silanol groups at both ends.

Molecule about the polysiloxane obtained! - (by gel permeation chromatography.

Polystyrene equivalent molecular weight. ) and OH groups, the results are shown below, indicating that the molecular weight is controlled and the degree of dispersion is small.

MW: 44500Mn
: 41200 (calculated value = 40000) Dispersity (Mw/Mn): 1.10H group
: 0.09% by weight (calculated value -0,085) Reference Example A method for producing polysiloxane having 5t-H groups at both ends.

Both terminal silanol-modified polysiloxane 1001 produced in Example 1 - Dry Tetrahydro7ran 10 (1 g/
14.8 yi of triethylamine was added thereto, and 18.39 f of dimethylchlorosilane was added dropwise over about 10 minutes under a nitrogen stream, followed by stirring for 5 hours to react. Post-treatment was carried out in the same manner as in Example 1 to obtain linear siloxane 102y having 5i-H groups at both ends.

Molecular weight in terms of styrene. ) and H equivalent, the results are as follows:
As shown below, it can be seen that the molecular weight and molecular weight distribution are very well controlled.

Mw: 1750 Mn: 1600 (calculated value = 1600) Partiality (Ivtw/Mn): Ll (equivalent
:870 (f1 mol-H) [Effect] As is clear from the above, according to the present invention, the reaction for producing a polysiloxane modified with silanol groups at both ends can be carried out at room temperature, which is safer and more effective than the conventional equilibration reaction. A polysiloxane modified with silanol groups at both terminals can be produced at low cost.

The second effect is that there are no by-products7). Previously 10'I! /,% cyclic oligomer Kanakuraden 1 and 2.

The third effect is that it is easy to control the molecular weight.

In the conventional method, there is no end point and the molecular weight increases moment by moment, but in the method of the present invention, there is an end point (2, the molecular weight remains at a constant value and does not change over time.

that's all

Claims (4)

[Claims] (1) In a polar solvent without active hydrogen, in the presence of a lithium-based catalyst of 0.1 to 10 mol% based on the initiator, using water as an initiator, a cyclic polysiloxane represented by the general formula (A) is prepared. A method for producing a polysiloxane represented by the general formula [B], which comprises anionically polymerizing one type or a mixture of two or more types. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・[A] ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・[B] [However, R^1 is a methyl group or phenyl group, R ^2 is a methyl group, phenyl group, or C_mF_2_m_+_1C_
2H_4 groups (m = 1 to 10), p is 3 or 4, n
is 3-400. ] (2) Claim (1) characterized in that the lithium-based catalyst is metallic lithium, lithium hydride, butyl lithium, lithium hydroxide, or a mixture of two or more thereof.
The method for producing polysiloxane described in . (3) The amount of lithium-based catalyst used is 0 relative to the water used as an initiator.
．． Claim (1) characterized in that the amount is 1 to 2.0 mol%.
) or the method for producing polysiloxane according to (2). (4) A claim characterized in that tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethyl formamide, dimethyl sulfoxide, or a mixture of two or more thereof is used as the polar solvent having no active hydrogen. The method for producing polysiloxane according to (1), (2) or (3).