JPH1045914A - Production of spherical polyorganosilsesquioxane powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a spherical polyorganosilsesquioxane powder having a relatively large mean particle diameter at good efficiency with respect to time and the volume of an apparatus by hydrolyzing a specified organotrialkoxysilane under specified conditions and polycondensing the hydrolyzate. SOLUTION: An organotrialkoxysilane represented by the formula: R<1> Si(OR<2> )3 [wherein R<1> is CH3 or a phenyl; and R<2> is a (substituted) alkyl] is hydrolyzed under acidic conditions including the use of desirably an organic acid (e.g. acetic acid) to form a water/alcohol solution of an organosilanetriol represented by the formula: R<1> Si(OH)3 and/or its partial hydrolyzate. After adding an aqueous alkali solution desirably ammonia water to the solution, it is uniformly mixed at once. Next, this system is left in a quiescent state to polycondense the organosilanetriol or its partial condensate. In this way, a spherical polyorganosilsesquioxane powder having a mean particle diameter of 1-15μm is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a spherical polyorganosilsesquioxane powder, and more particularly, to a method for efficiently producing such a powder, particularly a powder having an average particle diameter of 1 to 15 .mu.m.

[0002]

2. Description of the Related Art Conventionally, as a method for obtaining a polyorganosilsesquioxane powder, there has been known a method of reacting a trifunctional organosilane such as organotrichlorosilane and organotrialkoxysilane in an alkaline aqueous solution.

For example, Belgian Patent No. 572,412
The publication discloses a method for obtaining solid polymethylsilsesquioxane by hydrolyzing methyltrichlorosilane in spray water or by dropping into a large amount of water while stirring to hydrolyze. However, in this method, the amount of heat generated during the hydrolysis reaction is large, and a large amount of hydrogen chloride is by-produced, so that the apparatus is corroded, and in addition to the generated polymethylsilsesquioxane powder, by-products are generated. Since hydrogen chloride and unreacted methyltrichlorosilane remain in the system, there is a problem that a relatively large amount of chlorine atoms remains.

As a method for solving the above problem, Japanese Patent Application Laid-Open No. 54-72300 discloses a method in which the amount of chlorine is 0.1 to 5.0.
A method of hydrolyzing and condensing 0% by weight of methyltrialkoxysilane and / or a partial hydrolyzate thereof in an aqueous solution containing an alkaline earth metal hydroxide or an alkali metal carbonate is disclosed. However, in this method, there is a problem that moisture is easily absorbed because an alkaline earth metal or an alkali metal remains in a relatively large amount together with the generated polymethylsilsesquioxane powder. In this method, the chlorine content of the raw material methyltrialkoxysilane and / or its partial hydrolyzate is
There is also a problem that it must be adjusted to 0.1 to 0.5% by weight in advance.

[0005] As a method for solving the above problems, Japanese Patent Application Laid-Open No. 60-13813 discloses that methyltrialkoxysilane and / or its partial hydrolyzate can be prepared by converting the methyltrialkoxysilane and / or its partial hydrolyzate. Excellent free-flowing properties by hydrolysis and condensation in an aqueous solution of ammonia or amine in an amount sufficient to neutralize the chlorine atoms present in the product, plus an effective amount as a catalyst A method for obtaining a polyorganosilsesquioxane powder is disclosed. However, this method eliminates unreacted substances and impurities remaining in the system, but it is difficult to obtain spherical polyorganosilsesquioxane powder.

As a method for solving the above problems, Japanese Patent Application Laid-Open No. 63-77940 discloses methyltrialkoxysilane and / or its partial hydrolyzate, or methyltrialkoxysilane and / or its hydrolyzate. The mixed solution with the organic solvent is the upper layer, the mixed solution of the ammonia and / or the amine and the organic solvent is the lower layer, and methyltrialkoxysilane and / or its partial hydrolyzate is hydrolyzed and condensed at the interface between them. A method is disclosed for obtaining a polyorganosilsesquioxane powder in which the shape of each particle is an independent true sphere and the particle size distribution is in the range of ± 30% of the average particle diameter. The polyorganosilsesquioxane powder obtained by such a method has the characteristics that the shape of the particles is spherical, the particle size is small, the hydrophobicity is high, the cohesiveness is small, the specific gravity is small, and the particles are small. There is an advantage that a powder having a uniform diameter can be obtained.

As an improvement of this technique, Japanese Patent Application Laid-Open No. Sho 63-29
No. 5637 discloses that the amount of methyltrialkoxysilane and / or its partial hydrolyzate used is
/ 10 or less, particularly by setting the concentration of ammonia and / or amine to 0.01 to 5% by weight.
It is disclosed that a spherical polymethylsilsesquioxane fine powder having an average particle diameter of 0.05 to 0.8 μm and a narrow particle diameter distribution can be obtained.

[0008] The polymethylsilsesquioxane fine powder obtained by such a method has the characteristics of spherical particles, small particle diameter, high hydrophobicity, low cohesiveness and low specific gravity. Another advantage is that particles having a uniform particle diameter can be obtained. Therefore, it is also used as a modifying additive for paints, plastics, rubber, cosmetics, paper and the like.

[0009] However, such a method for producing a spherical polyorganosilsesquioxane fine powder requires maintenance of a reaction interface for hydrolyzing and condensing organoalkoxysilane and / or a partial hydrolyzate thereof, which is complicated. There is a problem that the production efficiency with respect to the device volume is low.

Further, Japanese Patent Application Laid-Open No. 1-217039 discloses that an organosilanetriol obtained by hydrolyzing an organotrialkoxysilane in the presence of an organic acid or a partial condensate thereof is treated with an aqueous alkali solution or an aqueous solution of an alkali. Various organic groups can be introduced by performing a polycondensation reaction in a mixed solution with a solvent, and a technique for obtaining a spherical polyorganosilsesquioxane fine powder having a very small particle diameter and a uniform particle diameter can be introduced. Have been. However, this method is a method in which an organosilanetriol or a partial condensate thereof is added to an aqueous alkali solution and a polycondensation reaction is sequentially performed, and there is a problem that a powder having a relatively large particle diameter is difficult to obtain.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to prevent by-products and unreacted alkoxy groups from remaining in a powder or on the surface of a powder during a hydrolysis or polycondensation reaction. An object of the present invention is to provide a method for producing a spherical polyorganosilsesquioxane powder efficiently with respect to an apparatus volume. In particular, the present invention has an average particle diameter of 1 to 15
It is an object of the present invention to be applicable to the production of spherical polyorganosilsesquioxane powder of μm.

[0012]

Means for Solving the Problems The present inventor has conducted various studies to achieve the above object, and as a result, has found that organosilanetriols obtained by hydrolyzing organotrialkoxysilanes and / or partial condensates thereof are obtained. The inventors have found that the above object can be achieved by adding an alkaline aqueous solution to a water / alcohol solution, mixing, and then allowing the mixture to stand, thereby completing the present invention.

[0013] Namely, the present invention is, (A) the general formula: _{^{R 1 Si (OR 2) 3}} (I) ( wherein, R ¹ represents a methyl group or a phenyl group, R ²
Is a substituted or unsubstituted alkyl group), and hydrolyzes an organotrialkoxysilane represented by the general formula: R ¹ Si (OH) ₃ (II) wherein R ¹ is Obtaining a water / alcohol solution of the organosilanetriol and / or a partial condensate thereof; and (B) obtaining a water / alcohol solution of the organosilanetriol and / or a partial condensate thereof.
Adding an alkaline aqueous solution to the alcohol solution, mixing and further standing still, and polycondensing the organosilanetriol or a partial condensate thereof to form a spherical polyorganosilsesquioxane powder. The present invention relates to a method for producing a spherical polyorganosilsesquioxane powder.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the production process of the present invention, the first step (A) comprises the step of hydrolyzing an organotrialkoxysilane represented by the above general formula (I) in the presence of an acid to obtain a compound of the above general formula (I) This is a step of obtaining an organosilanetriol and / or a partial condensate thereof shown in II).

In the organotrialkoxysilane used, R ¹ is a methyl group or a phenyl group, and both may be used in combination. A methyl group is preferred because of good reactivity and good yield. R ² is an alkyl group such as methyl, ethyl, propyl, butyl;
Alkoxy-substituted hydrocarbon groups such as methoxyethyl and 2-ethoxyethyl are exemplified, and methyl, ethyl and 2-methoxyethyl groups are preferred because of high hydrolysis rate. Examples of such organotrialkoxysilanes include methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, methyltriisopropoxysilane, methyltris (2-methoxyethoxy) silane, phenyltrimethoxysilane and phenyltriethoxysilane. A silane is exemplified, and one kind may be used, or two or more kinds may be mixed and used in combination.

The hydrolysis of the organotrialkoxysilane is carried out under acidic conditions. That is, using an acid as a catalyst,
Use in the form of an aqueous solution. As the acid, since the reaction rate is fast and impurities such as ionic substances that limit the use of the polyorganosilsesquioxane powder finally obtained are not left, or the amount is small even if it is left. It is preferable to use an organic acid. Examples of such organic acids include formic acid, acetic acid, propionic acid, monochloroacetic acid, oxalic acid, citric acid, and the like, but the reaction rate of hydrolysis is increased in a small amount, and the generated polyorganosilanetriol is By suppressing the partial condensation reaction,
Formic acid and acetic acid are particularly preferred.

Further, hydrogen chloride or an organochlorosilane such as methyltrichlorosilane which is contained as a trace amount as an impurity of the organotrialkoxysilane can be used as a catalyst or a catalyst precursor.

The amount of the acid used depends on the type of the silane and the acid, but 1 × 1 to 100 parts by weight of water used for hydrolyzing the organotrialkoxysilane.
The amount is preferably from 0 ^-3 to 1 part by weight, more preferably from 5 x 10 ^{-3 to} 0.1 part by weight. When the amount is less than 1 × 10 ⁻³ parts by weight, the reaction does not proceed sufficiently. When the amount exceeds 1 part by weight, not only the concentration remaining as acid groups in the impurities in the system becomes high, but also the product is formed. Organosilanetriol is easily condensed.

The amount of water used in the hydrolysis reaction is preferably from 2 to 60 mol, more preferably from 10 to 50 mol, per mol of the organotrialkoxysilane. The amount of water is 2
If less than the mole, the hydrolysis reaction does not proceed sufficiently,
If it exceeds 60 mol, a partial condensate of organosilanetriol tends to precipitate. To obtain a powder having a larger particle size, it is preferable to use a larger amount of water.

The hydrolysis temperature is not particularly limited, and the hydrolysis may be carried out at room temperature or in a heated state. However, in order to obtain organosilanetriol in good yield, the hydrolysis temperature is preferably 5 to 60 ° C., preferably 2 to 60 ° C.
The reaction is preferably carried out at a temperature of 0 to 55 ° C. for 10 minutes to 5 hours, preferably 40 minutes to 2 hours.

Thus, in the step (A), the organosilanetriol having R ¹ of the organotrialkoxysilane used and / or a partial condensate thereof is reacted with the excess water used for the hydrolysis. In the form of a solution dissolved in a mixture with an alcohol or a substituted alcohol formed by the above method.

The (B) second step of the production method of the present invention comprises:
(A) From a water / alcohol solution (hereinafter referred to as a silanol solution) of an organosilanetriol and / or a partial condensate thereof obtained in the first step or further diluted with water, is subjected to a polycondensation reaction. This is a step of obtaining a spherical polyorganosilsesquioxane powder. The reaction in the second step is carried out by rapidly adding and mixing an alkaline aqueous solution to the silanol solution, and further allowing the uniformly mixed system to stand still.

The alkaline aqueous solution shows basicity and acts as a neutralizer for the organic acid used in the first step and as a catalyst for the polycondensation reaction in the second step. Examples of the alkaline substance of the alkaline aqueous solution include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; ammonia; and organic amines such as monomethylamine and dimethylamine. it can. Among these, ammonia and organic amines are preferable because they do not leave trace amounts of impurities that limit the use of the obtained spherical polyorganosilsesquioxane powder, and ammonia is preferable because of low toxicity and easy removal. Is particularly preferred.

The amount of the alkaline aqueous solution used is such that it neutralizes the acid and effectively acts as a catalyst for the polycondensation reaction. That is, assuming that the amount required for neutralization is exceeded, for example, the concentration is 1 to 50% by weight, preferably 5% by weight.
0.01 to 1.0 part by weight, preferably 0.05 to 0 part by weight, based on 100 parts by weight of the silanol solution obtained in the first step or diluted with water, 0.5 parts by weight.

(B) In the second step, a silanol solution is charged into a reaction vessel, the above-mentioned alkaline aqueous solution is added to the silanol solution, and the mixture is rapidly and uniformly mixed by any means such as stirring. The method of addition is not particularly limited as long as it can be added effectively during the minimum mixing time, and may be added from above the silanol solution or may be fed into the solution via a nozzle or the like. The mixing time is suitably the minimum time required to dissolve the alkali catalyst in the reaction system, for example, 5 to 30 ° C, preferably 10 to 30 ° C.
0.5 to 3 including the addition time at a temperature of
It is carried out for 0 minutes, preferably for 0.5 to 15 minutes, more preferably for 0.5 to 10 minutes.

After uniform mixing, the system is allowed to stand to complete the polycondensation. In the standing, a particle having a preferable particle size is obtained, and the efficiency with respect to time and volume of the apparatus is excellent. For example, 30 minutes to 24 hours, preferably 30 minutes to 10 hours, more preferably 1 to 30 hours at the above-mentioned mixing temperature. Perform for 6 hours. In order to obtain a powder having a larger particle size, it is preferable to perform the standing at a lower temperature.

By carrying out the polycondensation reaction in the step (B), the spherical polyorganosilsesquioxane powder having R ¹ of the used organosilanetriol and / or its partial condensate is added to a water / alcohol mixture. In the form of a dispersion or a sol. The spherical polyorganosilsesquioxane powder obtained by the present invention can be used in the form of such a dispersion or sol, and if necessary, further subjected to appropriate treatment such as filtration, drying, and crushing. And can be recovered as fine powder.

[0028]

According to the production method of the present invention, it is possible to use a high-concentration alkaline aqueous solution, and the spherical polyorganosilsesquioxane powder, which has been difficult to produce efficiently by the conventional method, can be prepared in a time and an apparatus volume. Can be efficiently manufactured. The production method of the present invention is 1 to 15 μm, which has been more difficult to produce efficiently with the conventional method,
In particular, it is more effective when applied to the production of a spherical polyorganosilsesquioxane powder having a relatively large average particle diameter of 3 to 10 μm.

The polyorganosilsesquioxane powder obtained by the production method of the present invention is insoluble and non-meltable in an organic solvent, has excellent water repellency and lubricity on its surface, and is superior to inorganic powders. While having a small specific gravity, it has the characteristics of being superior in heat resistance to organic powders, less cohesive, and excellent in dispersibility. Therefore, taking advantage of such characteristics, it is useful as a filler for paints, plastics, rubbers, papers, etc., a slipperiness improver, a component of cosmetics, and the like.

[0030]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. In these examples, parts represent parts by weight. The present invention is not limited by these examples.

Example 1 First Step In a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer, 2,700 parts of water and 1 part of acetic acid were charged and stirred to form a uniform solution. When 1,360 parts of methyltrimethoxysilane having a hydrochloric acid content of 1 ppm was added thereto with stirring, the hydrolysis reaction proceeded, and the temperature rose to 53 ° C. in about 5 minutes. After continuing stirring for 50 minutes, the mixture was cooled to 20 ° C. to obtain a silanol solution.

Second Step The first step is carried out in a reaction vessel equipped with a thermometer, a reflux unit and a stirrer.
800 parts of the silanol solution obtained in the process and 1,000 parts of water
The parts were mixed to prepare a reaction solution. The temperature of the reaction solution was adjusted to 20 ° C., and while stirring at 20 rpm, 2 parts of a 25% aqueous ammonia solution was added, and the mixture was stirred for 1 minute.
Let stand for hours. In this step, powder was precipitated about 3 minutes and 30 seconds after the addition of the aqueous ammonia solution, and the entire reaction vessel became cloudy. After standing for 1 hour, the reaction solution was passed through a 200-mesh wire gauze, and then subjected to suction filtration for about 30 minutes using a quantitative filter paper No. 5B manufactured by Advantech Toyo, and dewatered to obtain a wet cake. . This at 200 ° C for 1
After heating and drying for 2 hours, the mixture was pulverized with a jet mill to recover 127 parts of white powder. This corresponds to 96% of the theoretical yield based on the methyltrimethoxysilane used.

When this powder was observed with an electron microscope,
The powder is spherical, with a maximum particle size of 5.5 μm,
The minimum value was 1.0 μm, and the average particle size measured by a particle size distribution analyzer was 2.7 μm.

This powder is placed in a magnetic crucible, and placed in air for 9 hours.
When heated to 00 ° C. for pyrolysis, the remaining amount was 89.0.
%Met. This is a value close to the theoretical amount of 89.6%, in which polymethylsilsesquioxane is oxidized and thermally decomposed into silicon dioxide. Also, as a result of X-ray analysis of this pyrolyzate,
It was confirmed to be amorphous silica. From this,
It was confirmed that the obtained white powder was polymethylsilsesquioxane.

Example 2 First Step The first step was carried out in the same manner as in Example 1 to obtain a silanol solution.

Step 2 A 25% aqueous ammonia solution was added, stirred and allowed to stand as in Example 1, except that the temperature of the reaction solution was changed to 15 ° C.
Approximately 4 minutes and 45 seconds after the addition of the aqueous ammonia solution, powder precipitated, and the entire reaction vessel became cloudy. After standing still, Example 1
And 125 parts of a white powder of polymethylsilsesquioxane were recovered. This corresponds to 95% of the theoretical yield based on the methyltrimethoxysilane used.

When this powder was observed with an electron microscope,
The powder is spherical, with a maximum particle size of 7.5 μm,
The minimum value was 1.5 μm, and the average particle size measured by a particle size distribution analyzer was 3.2 μm.

Example 3 First Step The first step was performed in the same manner as in Example 1 to obtain a silanol solution.

Step 2 A 25% aqueous ammonia solution was added and the mixture was stirred and allowed to stand as in Example 1, except that the temperature of the reaction solution was 10 ° C.
About 6 minutes after the addition of the aqueous ammonia solution, powder precipitated, and the entire reaction vessel became cloudy. After standing, the same treatment as in Example 1 was performed, and 125 parts of a white powder of polymethylsilsesquioxane was recovered. This corresponds to 95% of the theoretical yield based on the methyltrimethoxysilane used.

When this powder was observed with an electron microscope,
The powder has a spherical shape and the maximum particle size is 8.0 μm,
The minimum value was 1.8 μm, and the average particle size measured by a particle size distribution analyzer was 4.5 μm.

Example 4 First Step In a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer, 4,107 parts of water and 1 part of acetic acid were charged and stirred to form a uniform solution. When 680 parts of methyltrimethoxysilane having a hydrochloric acid content of 1 ppm was added thereto with stirring, the hydrolysis reaction proceeded, and the temperature rose to 38 ° C. in about 3 minutes. After continuing stirring for 50 minutes, the mixture was cooled to 20 ° C. to obtain a silanol solution.

Second Step The first vessel is placed in a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer.
Charge 1,590 parts of the silanol solution obtained in the process,
The reaction solution was used. The temperature of the reaction solution was adjusted to 20 ° C., and while stirring at 20 rpm, 2 parts of a 25% aqueous ammonia solution was added. After stirring for 1 minute, the stirring was stopped and allowed to stand for 1 hour. In this step, powder was precipitated about 5 minutes and 40 seconds after the addition of the aqueous ammonia solution, and the entire reaction vessel became cloudy. After standing for 1 hour, the same processing as in Example 1 was performed.
109 parts of white powder of polymethylsilsesquioxane was recovered. This corresponds to 98% of the theoretical yield based on the methyltrimethoxysilane used.

When this powder was observed with an electron microscope,
The powder is spherical, with a maximum particle size of 5.0 μm,
The minimum value was 3.5 μm, and the average particle size measured by a particle size distribution analyzer was 4.3 μm.

Example 5 First Step The first step was carried out in the same manner as in Example 4 to obtain a silanol solution.

Step 2 A 25% aqueous ammonia solution was added, stirred and allowed to stand as in Example 4, except that the temperature of the reaction solution was changed to 15 ° C.
A powder was precipitated about 8 minutes after the addition of the aqueous ammonia solution, and the entire reaction vessel became cloudy. After standing, the same treatment as in Example 1 was performed to recover 108 parts of a white powder of polymethylsilsesquioxane. This corresponds to 97% of the theoretical yield based on the methyltrimethoxysilane used.

When this powder was observed with an electron microscope,
The powder is spherical, with a maximum particle size of 7.3 μm,
The minimum value was 4.5 μm, and the average particle size measured by a particle size distribution analyzer was 6.1 μm.

Example 6 First Step The first step was carried out in the same manner as in Example 4 to obtain a silanol solution.

Second Step A 25% aqueous ammonia solution was added, stirred and allowed to stand as in Example 4, except that the temperature of the reaction solution was 10 ° C.
Approximately 9 minutes and 40 seconds after the addition of the aqueous ammonia solution, the powder precipitated, and the entire reaction vessel became cloudy. After standing still, Example 1
And 109 parts of a white powder of polymethylsilsesquioxane were recovered. This corresponds to 98% of the theoretical yield based on the methyltrimethoxysilane used.

When this powder was observed with an electron microscope,
The powder has a spherical shape, and the maximum particle size is 9.3 μm.
The minimum value was 5.3 μm, and the average particle size measured by a particle size distribution analyzer was 7.3 μm.

Example 7 First Step A reaction vessel equipped with a thermometer, a reflux condenser and a stirrer was charged with 1,800 parts of water, and stirred with a hydrochloric acid component of 1,800.
Methyltrimethoxysilane 300 containing 000 ppm
When the part was added, the hydrolysis reaction proceeded, and the temperature rose to 30 ° C. in about 20 minutes. After further stirring for 30 minutes, the mixture was cooled to 20 ° C. to obtain a silanol solution.

Second Step The first step is carried out in a reaction vessel equipped with a thermometer, a reflux unit and a stirrer.
Charge 2,100 parts of the silanol solution obtained in the process,
The reaction solution was used. The temperature of the reaction solution was adjusted to 15 ° C., and while stirring at 10 rpm, 7 parts of a 25% aqueous ammonia solution was added. After stirring for 1 minute, the stirring was stopped and allowed to stand for 4 hours. In this step, powder was precipitated about 2 minutes after the addition of the aqueous ammonia solution, and the entire reaction vessel became cloudy.
After standing for 1 hour, the same treatment as in Example 1 was performed except that drying and crushing of the wet cake were performed using a thermjet.
After a filtration time of 142 minutes, 142 parts of a white powder of polymethylsilsesquioxane were recovered. This corresponds to 96% of the theoretical yield based on the methyltrimethoxysilane used.

When this powder was observed with an electron microscope,
The powder has a spherical shape and the maximum particle size is 19.0 μm.
The minimum value was 1.0 μm, and the average particle size measured by a particle size distribution analyzer was 10 μm.

Comparative Example 1 First Step The first step was carried out in the same manner as in Example 7 to obtain a silanol solution.

Second Step After adding a 25% aqueous ammonia solution, polycondensation was carried out in the same manner as in Example 7, except that stirring was continued for 4 hours without standing. As a result, a dispersion containing powder was not obtained, and a hard gel-like cured product was obtained.

Comparative Example 2 First Step The procedure of Example 7 was repeated, except that the amount of water was changed to 360 parts.
A silanol solution was obtained.

Second Step 900 parts of ethanol, 180 parts of water and 9 parts of a 28% aqueous ammonia solution were placed in a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer, and the temperature was set at 25.degree. Then 1
While stirring at 0 rpm, 660 parts of the silanol solution obtained in the first step were added over 10 minutes, and stirring was continued for another 10 minutes. Thereafter, the stirring was stopped, and the system was allowed to stand for 24 hours in a stationary state. As a result, the system was in the form of a translucent gel. This reaction solution was subjected to suction filtration using a quantitative filter paper No. 5B manufactured by Advantech Toyo in the same manner as in Example 7. As a result, clogging occurred due to the fine particle diameter of the generated fine powder. A wet cake was obtained through filtration. Example 7
The wet cake was dried and crushed by using a thermjet in the same manner as in the above to obtain 140 parts of a fine white powder of polymethylsilsesquioxane. This corresponds to 95% of the theoretical yield based on the methyltrimethoxysilane used.

Observation of this fine powder with an electron microscope revealed that the fine powder had a spherical shape and the maximum particle size was 0.0
The minimum value was 6 μm, the minimum value was 0.01 μm, and the average particle diameter measured by a particle size distribution analyzer was 0.04 μm. As described above, in the method of adding organosilanetriol to the aqueous alkali solution, even when the stationary state after stirring was maintained for a long time, a polyorganosilsesquioxane powder having a particularly large particle size was not obtained.

Example 8 First Step In a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer, 2,700 parts of water and 1 part of acetic acid were charged and stirred to form a uniform solution. When 1,980 parts of phenyltrimethoxysilane having a hydrochloric acid content of 1 ppm was added thereto while stirring, the hydrolysis reaction proceeded, and the temperature rose to 53 ° C. in about 15 minutes. After continuing stirring for 45 minutes, the mixture was cooled to 20 ° C. to obtain a silanol solution.

Second step: The first vessel was placed in a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer.
800 parts of the silanol solution obtained in the process and 1,000 parts of water
The parts were mixed to prepare a reaction solution. The temperature of the reaction solution was adjusted to 20 ° C., while stirring at 20 rpm, 1 part of a 25% aqueous ammonia solution was added, and the mixture was stirred for 1 minute.
Let stand for hours. In this step, powder was precipitated about 2 minutes and 30 seconds after the addition of the aqueous ammonia solution, and the entire reaction vessel became cloudy. After standing for 1 hour, the reaction solution was passed through a 200-mesh wire net, and then filtered and dehydrated in the same manner as in Example 1 to obtain a wet cake. After drying this wet cake at 200 ° C. for 12 hours, it was crushed by a jet mill to recover 202 parts of a white powder. This corresponds to 92% of the theoretical yield based on the phenyltrimethoxysilane used.

When this powder was observed with an electron microscope,
The powder is spherical, with a maximum particle size of 7.5 μm,
The minimum value was 1.0 μm, and the average particle size measured by a particle size distribution analyzer was 3.8 μm.

Example 9 First Step In a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer, 2,700 parts of water and 1 part of acetic acid were charged and stirred to form a uniform solution. When 1,780 parts of methyltriethoxysilane having a hydrochloric acid content of 1 ppm was added thereto while stirring, the hydrolysis reaction proceeded, and the temperature rose to 53 ° C. in about 30 minutes. After further stirring for 60 minutes, the mixture was cooled to 20 ° C. to obtain a silanol solution.

Second Step The first vessel is placed in a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer.
800 parts of the silanol solution obtained in the process and 1,000 parts of water
The parts were mixed to prepare a reaction solution. The temperature of the reaction solution was adjusted to 20 ° C., and while stirring at 20 rpm, 2 parts of a 25% aqueous ammonia solution was added, and the mixture was stirred for 1 minute.
Let stand for hours. In this step, powder was precipitated about 8 minutes and 30 seconds after the addition of the aqueous ammonia solution, and the entire reaction vessel became cloudy. After standing for 1 hour, the reaction solution was passed through a 200-mesh wire net, then filtered and dehydrated to obtain a wet cake. The wet cake was dried by heating at 200 ° C. for 12 hours, and then pulverized with a jet mill to recover 115 parts of a white powder. This corresponds to 96% of the theoretical yield based on the methyltriethoxysilane used.

When this powder was observed with an electron microscope,
The powder is spherical, with a maximum particle size of 9.5 μm,
The minimum value was 2.3 μm, and the average particle size measured by a particle size distribution analyzer was 6.7 μm.

Claims (1)

[Claims] 1. A (A) the general formula: in _{^{R 1 Si (OR 2) 3}} (I) ( wherein, R ¹ represents a methyl group or a phenyl group, R ²
Is a substituted or unsubstituted alkyl group), and hydrolyzes an organotrialkoxysilane represented by the general formula: R ¹ Si (OH) ₃ (II) wherein R ¹ is Obtaining a water / alcohol solution of the organosilanetriol and / or a partial condensate thereof; and (B) obtaining a water / alcohol solution of the organosilanetriol and / or a partial condensate thereof.
To the alcohol solution, add and mix the alkaline aqueous solution,
Further comprising allowing the organosilanetriol or a partial condensate thereof to undergo a polycondensation reaction in a stationary state to form a spherical polyorganosilsesquioxane powder. Sun powder manufacturing method.