JPH10231365A - Purification of polysilanes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently purify polysilanes by certainly removing components insoluble to organic solvent, through dissolving the polysilanes in an organic solvent as good solvent followed by addition as a poor solvent, and then conducting a filtration treatment. SOLUTION: Components, which are insoluble in organic solvent, and microgel both of which exist in component A as impurities are coagulated, and the coagulum thus formed is filtered off, by dissolving (A) polysilanes in (B) an organic solvent as good solvent followed by adding (C) a poor solvent for the component A to the system to effect deposition of trace amounts of high- molecular-weight polysilanes. The component A is obtained b reacting at least one kind of polyvalent halosilanes of formulas I-III [R<1> and R<2> are each (non) substituted monovalent hydrocarbon group; R<3> -R<6> are each H, OH, a halogen, or the like; Q is a (non)substituted divalent hydrocarbon group or the like; 1<=(a)<=2, 0<=(b)<=1, 1<=(a+b)<=2; 0<=(c)<=2, 0<=(d)<=1, 0<=(c+d)<=2; 0<=(p)<=1, 0<=(q)<=1, 0<=(p+q)<=2], with an alkali metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying polysilanes capable of efficiently purifying polysilanes by satisfactorily removing components and microgels insoluble in organic solvents present in the polysilanes.

[0002]

2. Description of the Related Art The most common method for synthesizing polysilanes is a method utilizing a polycondensation reaction of polyvalent halosilanes with an alkali metal or the like. The substance may include a component insoluble in an organic solvent or a microgel as an impurity. In particular, when a trifunctional or higher-functional halosilane is used as a raw material, a large amount of insolubles is generated. Furthermore, the obtained polysilanes may further generate insolubilized substances during long-term storage.

[0003] In the production process of polysilanes, it is necessary to wash with water in order to remove alkali halide as a by-product. However, the presence of the insoluble components as described above makes it difficult to separate the aqueous layer. This causes a reduction in yield and a reduction in production efficiency.

On the other hand, when polysilanes are applied to photoresists, photoreceptors, organic elements, etc., it is desired to form a uniform and smooth film from a polymer solution. For this reason, from the viewpoint of improving the yield, production efficiency and film formability,
It is necessary to remove insoluble components and microgels present in the reaction product.

Hitherto, as a method for removing the insoluble components, a method has been adopted in which polysilanes are dissolved in a good solvent organic solvent, and the obtained solution is subjected to centrifugation or filtration using a filter paper or the like. Was.

[0006] However, it is difficult to completely remove insoluble matter by the centrifugal separation method, so that it is difficult to obtain a smooth film.
It is not suitable for application to photoresists and the like. In addition, with respect to a filtration method using a filter paper or a filter plate, large insolubles of particles can be removed, but fine insolubles (microgel) cannot be removed, and the polymer solution becomes slightly turbid. State. Furthermore, it is conceivable to use a filter aid or the like in combination, but it is impossible to remove the microgel by this method. For this reason, films of polysilanes made from such turbid solutions have low transparency,
It has several problems such as poor surface smoothness.

When a membrane filter is used, insoluble components and microgels are swollen by a solvent and cause clogging, so that filtration and separation are extremely difficult or practically impossible. In this case, improvement can be seen by using a filter aid in combination, but it is still not a practical method because a very long filtration time is required.

Therefore, it is desired to develop a more efficient method for purifying polysilanes without the above-mentioned problems.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a polysilane which can surely remove components and microgels insoluble in an organic solvent present in the polysilane and can purify the polysilane efficiently. It is intended to provide a purification method.

[0010]

Means for Solving the Problems and Embodiments of the Invention As a result of intensive studies to achieve the above object, the present inventors have found that polysilanes containing insolubles (components insoluble in organic solvents, microgels) are obtained. Dissolves in good solvent organic solvent,
To the obtained polysilanes solution, a solvent having poor solvent for the polysilanes is added, and a small amount of a high molecular weight polysilane is precipitated to aggregate insoluble components and microgels present in the system, and then subjected to a filtration treatment. The inventors have found that by separating and removing the aggregates, insoluble components and microgels present in the polysilanes can be surely removed and the polysilanes can be efficiently purified, and the present invention has been accomplished.

According to the method for purifying polysilanes of the present invention, the insoluble components and microgels present in the polysilanes are precipitated as agglomerates, so that a simple filtration such as filtration with a filter paper is performed, whereby the polysilanes are separated in a short time. Thus, a high-purity polysilane polymer solution from which insoluble components and microgels are completely removed can be easily obtained. Further, the purification method of the present invention is also effective for removing insolubles generated during long-term storage.

Furthermore, in the polysilane production method in which an alkali metal is reacted with a polyvalent halosilane, when the above-mentioned purification step is carried out prior to the step of washing and removing by-product alkali halide, insoluble components and microgels are completely removed. By doing so, the water washing step becomes very easy, which can contribute to shortening of the process time and improvement of the yield.

Since the polysilanes obtained by the purification method of the present invention do not contain insoluble components and microgels, a film having high transparency can be prepared and a film having excellent surface smoothness can be obtained. Yes, it can be applied to various uses.

Accordingly, the present invention provides a method for dissolving polysilanes in a good solvent organic solvent, adding a poor solvent to the polysilanes solution to the obtained polysilanes solution, and depositing a trace amount of high molecular weight polysilanes. And then agglomerating the insoluble components and microgels present as impurities in the polysilanes, separating the aggregates by filtration, and removing the aggregates. Provided is a method for purifying polysilanes, wherein the above purification method is carried out prior to a step of washing and removing alkali halide by-produced in a method for producing polysilane in which halosilane is reacted.

Now, the present invention will be described in further detail. The polysilanes used in the method for purifying polysilanes of the present invention are not particularly limited. And those obtained by the reaction of polyhydric halosilanes.

In this case, one or more of the compounds represented by the following general formulas (1), (2) and (3) are used as the polyvalent halosilanes.

[0017]

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In the above formula (1), each of R ¹ and R ² is a substituted or unsubstituted alkyl group, aryl group or aralkyl group having preferably 1 to 12 carbon atoms, particularly 1 to 6 carbon atoms. Ethyl group, propyl group, butyl group, hexyl group, cyclohexyl group, phenyl group, tolyl group, naphthyl group, benzyl group and the like, and part or all of hydrogen atoms of these unsubstituted hydrocarbon groups, alkoxy group, amino And those substituted with a substituent such as an alkylamino group or a trialkylsilyl group.

R ³ , R ⁴ , R ⁵ and R ⁶ are each a hydrogen atom,
Hydroxyl group, a halogen atom such as chlorine or fluorine, an alkoxy group, an amino group, a substituted or unsubstituted monovalent hydrocarbon group, and as the alkoxy group, a methoxy group, an ethoxy group,
1 carbon atoms such as propoxy, butoxy, phenoxy, etc.
To 6 are mentioned. Examples of the substituted or unsubstituted monovalent hydrocarbon group include the same as the alkyl group, aryl group and aralkyl group having 1 to 12 carbon atoms, particularly 1 to 6 as described for R ¹ and R ² above.

Q is a substituted or unsubstituted divalent hydrocarbon group, or the following groups.

[0021]

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The divalent hydrocarbon group is preferably an alkylene group having 1 to 12 carbon atoms, especially 1 to 6 carbon atoms, an arylene group, or a group in which an alkylene group and an arylene group are bonded. , Propylene group,
Examples thereof include a butylene group, a hexylene group, a cyclohexylene group, a phenylene group, a tolylene group, a naphthylene group, and the following groups.

[0023]

Embedded image

A substituted divalent hydrocarbon group in which part or all of the hydrogen atoms of the unsubstituted divalent hydrocarbon group is substituted with a substituent such as an alkoxy group, an amino group, an alkylamino group or a trialkylsilyl group. It may be.

Z is a group represented by S, O or NR ⁷ , wherein R ⁷ is a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, particularly 1 to 6 carbon atoms, Can be exemplified.

A, b, c, d, p, and q are numbers satisfying the above expression, but preferably 1 ≦ a + b ≦ 2, 0 ≦ c +
d ≦ 2 and 0 ≦ p + q ≦ 2.

The degree of polymerization of the polysilanes is 10 or more. In the case of the polysilanes obtained by using the polyvalent halosilane of the above formula (3), -Si-Q-Si- units (polycarbosilane units) ) Is preferably not more than 50 mol%.

Specifically, the polysilanes include those represented by the following general formula (4).

[0029]

Embedded image (Where n ≧ 1, m ≧ 0, k ≧ 0, n + m + k> 10, preferably n ≧ 1, m ≧ 1, k ≧ 0. Also, n + m + k> 10, but preferably n + m + k
≧ 20, more preferably n + m + k ≧ 50, and the upper limit is not particularly limited. Preferably k / (n + m +
k) ≦ 0.5. Note that R ¹ , R ² , R ³ , R ⁴ ,
R ⁵ , R ⁶ , Q, a, b, c, d, p, and q have the same meaning as described above. )

When purifying the above polysilanes,
The polysilane may be immediately after synthesis or after long-term storage.

The organic solvent having good solvent properties of the polysilane containing the insoluble impurities is not particularly limited as long as it is an organic solvent capable of dissolving the polysilane, and examples thereof include toluene, xylene, tetrahydrofuran, methylene chloride, and chloroform. No. The amount of the organic solvent used is such that the concentration of the polysilane in the polysilane solution is 1 to 30.
%, Especially 5 to 15% by weight.

In the method of the present invention, a poor solvent for the polysilane is added to a solution in which the polysilane containing the insoluble impurities is dissolved in a good solvent organic solvent. In this case, examples of the poor solvent for the polysilanes include poor solvents such as hexane, methanol, ethanol, isopropyl alcohol, and acetone, depending on the substituents and the degree of polymerization of the polysilanes.
The addition amount of the solvent having poor solvent to the polysilane is 10 to 500% by weight, particularly 20% by weight to the polysilane solution.
When the amount is less than 10% by weight, an effective amount of the high molecular weight polysilane is not precipitated, and the component insoluble in the organic solvent present in the system and the microgel may not aggregate.

In the present invention, when a poor solvent is added to the polysilane as described above, a trace amount of a high molecular weight polysilane is precipitated, and at the same time, a component and a microgel insoluble in the organic solvent present in the polysilane are formed. The solution aggregates, and then the solution is filtered to easily separate and remove the aggregate.

Here, the method of the filtration is not particularly limited, and filtration using a filter paper, pressure filtration using a filter plate, or the like can be employed.

After the filtration treatment, by removing the solvent, high-purity polysilanes containing no insoluble impurities or microgel in the organic solvent can be obtained.

The purification method of the present invention is applicable to a method for producing a polysilane in which an alkali metal is reacted with a polyvalent halosilane as described above. In this case, after polycondensation reaction of polyvalent halosilanes using an alkali metal,
After the remaining alkali metal is quenched using alcohol, hydrolysis is performed, a large amount of poor solvent is added, the synthesized polysilanes are precipitated, and the polysilanes containing impurities are separated by filtration, and the alkali by-produced. It is preferable to perform the above-mentioned purification method prior to the step of washing and removing the halide. By performing the above-described purification step prior to the step of washing and removing the by-product alkali halide, the washing step becomes very easy, which can contribute to shortening of the process time and improvement of the yield.

[0037]

According to the method for purifying polysilanes of the present invention, components and microgels insoluble in organic solvents existing in polysilanes can be easily and satisfactorily removed in a short time, resulting in high transparency and high surface smoothness. A high-quality purified polysilane that gives a film excellent in degree can be industrially advantageously obtained.

[0038]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, Me represents a methyl group and Ph represents a phenyl group.

[Example 1]
Of methylphenyldichlorosilane with aluminum
(MePhSi) )_n(Mn 23,000
0, Mw 97000) 10 g dissolved in 90 g toluene
did. The appearance of this polysilane solution is slightly bluish white,
It contained fine insoluble components.

Next, 60 g of hexane was gradually added to the polysilane solution with stirring. When left at room temperature for 30 minutes, a small amount of the polysilane high molecular weight component was precipitated, and aggregated insolubles were precipitated. A filter plate (NA-500, retaining particle diameter 0.5 μm, diameter 47 m)
By performing pressure filtration (pressure 1.5 kg / cm ² ) using Advantech Toyo Co., Ltd., a colorless and transparent (MePhSi) _n toluene solution could be easily obtained. Removal of the solvent gave 9.5 g of (MePhSi) _n (Mn 22,200, Mw 89,0).
00) was recovered.

The 10% toluene solution of the above polymer easily passed through a membrane filter (diameter: 47 mm) having a pore size of 0.2 μm, confirming that fine insoluble components were removed.

Comparative Example 1 10 g of the same polysilane as in Example 1 was dissolved in 90 g of toluene. A filter plate (NA-500, retaining particle size 0.5 μm) is applied to this polysilane solution.
m, diameter 47 mm, manufactured by Advantech Toyo Co., Ltd.), and the resulting solution was pale blue-white and contained fine insoluble components.

Comparative Example 2 10 g of the same polysilane as in Example 1 was dissolved in 90 g of toluene. This polysilane solution was subjected to pressure filtration using a membrane filter (diameter: 47 mm) having a pore diameter of 0.2 μm (pressure: 1.5 kg / cm).
² ) was carried out for 1 hour, but finally clogging occurred and the amount of the solution passed was 55 g, and it was difficult to completely remove insolubles by this method.

Example 2 A compound was synthesized in the same manner as in Example 1,
(MePhSi) _n (Mn 19,0
(00, Mw 82,000) was dissolved in 90 g of toluene. The appearance of this polysilane solution was slightly yellowish, slightly blue-white, and contained fine insoluble components.

Next, 45 g of isopropyl alcohol was gradually added to this solution with stirring. When left at room temperature for 30 minutes, a small amount of the polysilane high molecular weight component was precipitated, and aggregated insolubles were precipitated. A filter plate (NA-500, retaining particle diameter 0.5 μm, diameter 4
By performing pressure filtration (pressure 1.5 kg / cm ² ) using 7 mm, manufactured by Advantech Toyo Co., Ltd., a colorless and transparent (MePhSi) _n toluene solution could be easily obtained. By removing the solvent, 9.1 g
(MePhSi) _n (Mn 17,800, Mw 76,
000) was recovered.

Since the resulting 10% toluene solution of the above polymer easily passed through a membrane filter (diameter: 47 mm) having a pore diameter of 0.2 μm, it was confirmed that fine insoluble components were removed.

Comparative Example 3 10 g of the same polysilane as in Example 2 was dissolved in 90 g of toluene. A filter plate (NA-500, retaining particle size 0.5 μm) is applied to this polysilane solution.
m, a diameter of 47 mm, and pressure filtration (pressure 1.5 kg / cm ² ) using Advantech Toyo Co., Ltd., the resulting solution was pale bluish white and contained fine insoluble components. .

Comparative Example 4 10 g of the same polysilane as in Example 2 was dissolved in 90 g of toluene. The polysilane solution was subjected to pressure filtration using a membrane filter (diameter: 47 mm) having a pore diameter of 0.2 μm for 1 hour. Clogging finally occurred, and the amount of the solution passed was 25 g. It was difficult to completely remove insolubles by the method.

Example 3 Under a nitrogen stream, 2.88 g (125 mmol) of metallic sodium and 30 g of xylene were placed in a four-necked flask, and heated and stirred at 140 ° C. to form a sodium dispersion. When 9.6 g (50 mmol) of dichlorosilane was added dropwise, the reaction proceeded exothermically, and the solution turned purple. After heating under reflux and stirring for 7 hours, sodium was inactivated using 5 ml of methanol, and hydrolysis was performed using 50 g of water. Since the reaction mixture contained insolubles, the organic layer and the aqueous layer were not separated. Next, 100 g of isopropyl alcohol was added to precipitate a polymer, and suction-filtration using filter paper was performed to obtain a polysilane containing an insoluble matter.

Toluene 6 was added to the obtained polysilane polymer.
0 g was added, followed by the gradual addition of 48 g of hexane.
When left at room temperature for 30 minutes, a small amount of the polysilane high molecular weight component was precipitated, and aggregated insolubles precipitated.
This solution is easily subjected to pressure filtration (pressure 1.5 kg / cm ² ) using a filter plate (NA-500, retaining particle diameter 0.5 μm, diameter 47 mm, manufactured by Advantech Toyo Co., Ltd.), so that the solution can be easily obtained. A toluene solution of colorless and transparent polysilane was obtained.

Next, washing was performed five times to remove ionic impurities. The separation of the organic and aqueous layers is good,
The required time was within one hour. By concentrating the obtained organic layer, a high molecular weight methylphenylpolysilane (Mn 17,500, Mw 60,600) was obtained as a white solid in a yield of 48%.

Comparative Example 5 A polysilane was produced in the same manner as in Example 3, except that insolubles were not removed from the polysilane polymer using hexane. The separation of the organic layer and the aqueous layer was difficult due to the presence of insolubles, and the time required for the water washing step required 5 hours. The yield also dropped to 40%.

Example 4 Under a nitrogen stream, 2.88 g (125 mmol) of metallic sodium and 30 g of xylene were placed in a four-necked flask, and heated and stirred at 140 ° C. to form a sodium dispersion. When 9.6 g (50 mmol) of dichlorosilane and 0.42 g (2 mmol) of phenyltrichlorosilane were added dropwise, the reaction proceeded exothermically, and the solution turned purple. After heating under reflux and stirring for 7 hours, sodium was inactivated using 5 ml of methanol, and hydrolysis was performed using 50 g of water. Since the reaction mixture contained insolubles, the organic layer and the aqueous layer were not separated. Next, 100 g of isopropyl alcohol was added to precipitate a polymer, and suction-filtration using filter paper was performed to obtain a polysilane containing an insoluble matter.

[0054] Toluene 6 was added to the obtained polysilane polymer.
0 g was added, followed by the gradual addition of 48 g of hexane.
When left at room temperature for 30 minutes, a small amount of the polysilane high molecular weight component was precipitated, and aggregated insolubles precipitated.
This solution is easily subjected to pressure filtration (pressure 1.5 kg / cm ² ) using a filter plate (NA-500, retaining particle diameter 0.5 μm, diameter 47 mm, manufactured by Advantech Toyo Co., Ltd.), so that the solution can be easily obtained. A toluene solution of colorless and transparent polysilane was obtained.

Next, washing was performed five times to remove ionic impurities. The separation of the organic and aqueous layers is good,
The required time was one hour. By concentrating the obtained organic layer, polysilane (Mn18, 140, Mw39,
000) as a white solid in 44% yield.

Comparative Example 6 A polysilane was produced in the same manner as in Example 4 except that insolubles were not removed from the polysilane polymer using hexane. The separation of the organic layer and the aqueous layer was difficult due to the presence of insolubles, and the time required for the water washing step required 5 hours. The yield also dropped to 35%.

Example 5 31.3 g (1.36 mol) of sodium, 96.0 g (0.5 mol) of methylphenyldichlorosilane and 32.9 g of p-bis (dimethylchlorosilyl) benzene were refluxed in a toluene solvent. ((MePhSi) ₄ (Me ₂ Si—C ₆ H ₄ —SiM) obtained by reacting
polysilane represented by e _{2) 1] n} (Mn11,000, Mw41,
600) 10 g was dissolved in 90 g of toluene. This polysilane solution was a slightly turbid solution and contained fine insoluble components.

Next, hexane 5 was added while stirring this solution.
0 g was added slowly. When left at room temperature for 30 minutes, a small amount of a polysilane high molecular weight component was precipitated, and aggregated insolubles were precipitated. The solution was subjected to pressure filtration using a filter plate (NA-500, diameter 47 mm, manufactured by Advantech Toyo Co., Ltd.) (pressure 1.5 kg / c).
m ² ), colorless and transparent [(MeP
A toluene solution of hSi) ₄ (Me ₂ Si—C ₆ H ₄ —SiMe ₂ ) ₁ ] _n was obtained. By removing the solvent, 9.2 g of the polymer (Mn10,500, Mw3
9,900). Since the 10% toluene solution of this polysilane easily passed through a 0.2 μm membrane filter (47 mm in diameter) easily, it was confirmed that fine insoluble components were removed.

Comparative Example 7 10 g of the same polysilane as in Example 5 was dissolved in 90 g of toluene. The polysilane solution was subjected to pressure filtration (pressure 1.5 kg / cm ² ) using a filter plate (NA-500, diameter 47 mm, manufactured by Advantech Toyo Co., Ltd.). And contained fine insoluble components.

Comparative Example 8 10 g of the same polysilane as in Example 5 was dissolved in 90 g of toluene. The polysilane solution was subjected to pressure filtration (pressure 1.5 kg / cm ² ) using a membrane filter (diameter 47 mm) for 1 hour, but finally clogging occurred, and the amount of the solution passed was 80 g. Thus, it was difficult to completely remove insolubles by this method.

Continued on the front page (72) Inventor Kazumi Noda 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Pref. Shin-Etsu Chemical Co., Ltd.

Claims (3)

[Claims] 1. A polysilane obtained by dissolving a polysilane in an organic solvent having a good solvent, adding a solvent having a poor solvent to the polysilane to a solution of the obtained polysilane, and precipitating a trace amount of a high molecular weight polysilane. A method for purifying polysilanes, comprising aggregating insoluble components and microgels present as impurities in a product, followed by filtration to separate and remove the product. 2. The polysilanes represented by the following general formula (1):
The method for purifying polysilanes according to claim 1, which is obtained by reacting one or more polyvalent halosilanes represented by (2) and (3) with an alkali metal. Embedded image 3. A method for purifying polysilanes, wherein the purifying method according to claim 1 or 2 is carried out prior to the step of washing and removing alkali halide by-produced in the method for producing polysilane in which an alkali metal is reacted with polyvalent halosilanes. .