JPH06263875A - Production of fine polyorganosililsequioxane particle - Google Patents

Abstract

PURPOSE:To produce at good efficiency fine spherical particles made of a polyorganosilsesquioxane having various organic groups as well as of a polymethylsilsesquioxane which has difficultly been produced by a conventional process and having uniform particle diameters. CONSTITUTION:This production process consists of the steps of: hydrolyzing an organotrialkoxysilane of the general formula: R<1>Si(OR<2>) [wherein R<1> is an (un)substituted monovalent hydrocarbon group; and R is (un)substituted alkyl] in the presence of an organic acid to obtain an organosilanetriol of the general formula: R<1>Si(OH)3 (wherein R<1> is as defined above) or its partial condensate and polycondensing the organosilanetriol or its partial condensate in an aqueous alkali solution or a mixture of this solution with an organic solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polyorganosilsesquioxane fine particles, and more specifically, it has a wide range of organic groups capable of being bonded to silicon atoms, has a very small particle size, and has a particle shape. Relates to a method for producing polyorganosilsesquioxane fine particles having a spherical shape and a uniform particle diameter.

[0002]

2. Description of the Related Art Conventionally, as a method of obtaining a polyorganosilsesquioxane powder, a method of reacting a trifunctional silane such as organotrichlorosilane and organotrialkoxysilane in an aqueous alkali solution is known.
For example, in Belgian Patent No. 572,412,
A method for obtaining solid polymethylsilsesquioxane by hydrolyzing methyltrichlorosilane in spray water or by adding dropwise to a large amount of water while stirring is disclosed.

However, in this method, a large amount of heat is generated during the hydrolysis reaction, and a large amount of hydrogen chloride is by-produced, so that the equipment is corroded, and in addition to the polymethylsilsesquioxane powder produced, it is by-produced. Since hydrogen chloride and unhydrolyzed methyltrichlorosilane remain, there is a problem that a relatively large amount of chlorine atoms remain.

As a method for solving the above-mentioned problems, JP-A-54-72300 discloses that the chlorine content is 0.1-5.
A method of hydrolyzing and condensing 0% by weight of methyltrialkoxysilane and / or its partial hydrolyzate in an aqueous solution containing an alkaline earth metal hydroxide or an alkali metal carbonate is disclosed.

However, in this method, a relatively large amount of alkaline earth metal or alkali metal remains together with the polymethylsilsesquioxane powder produced, so that when used as a filler for various synthetic resins, it tends to absorb moisture. There is a point. Further, this method has a problem that the amount of chlorine of the raw material methyltrialkoxysilane and / or its partial hydrolyzate must be adjusted to 0.1 to 0.5% by weight in advance.

[0006] One of the inventors of the present invention has previously proposed that methyltrialkoxysilane and / or its partially hydrolyzed condensate is sufficient to neutralize chlorine atoms present in the silane and / or its partially hydrolyzed condensate. By hydrolyzing and condensing in an aqueous solution of ammonia or amine in an amount obtained by adding an amount as a catalyst to an arbitrary amount, the above problems are solved, and polymethylsilsesquioxane powder having excellent free-flowing property is obtained. Proposed technology (Japanese Patent Laid-Open No. Sho 60-1381)
(See Japanese Patent Publication No. 3).

Further, one of the inventors of the present invention is to use an upper layer of a liquid mixture of methyltrialkoxysilane and / or a partial hydrolysis-condensation product thereof or methyltrialkoxysilane and / or a partial hydrolysis-condensation product thereof and an organic solvent, and And / or a mixed solution of an amine and an organic solvent is used as a lower layer, and methyltrialkoxysilane and / or its partially hydrolyzed condensate is hydrolyzed at these interfaces.
Condensed, the shape of the particles are each independent spherical shape,
It has been found that a polymethylsilsesquioxane powder having a particle size distribution within the range of ± 30% of the average particle size can be produced (see JP-A-63-77940).

Furthermore, the inventors of the present invention set the amount of methyltrialkoxysilane and / or its partial hydrolyzate used in the above reaction to be 1/10 or less of the weight of water, particularly ammonia and / or amine. It has been found that a spherical polymethylsilsesquioxane powder having an average particle diameter of 0.05 to 0.8 μm can be obtained by adjusting the concentration to 0.01 to 5% by weight (JP-A-63-29).
5637).

The polymethylsilsesquioxane powder obtained by such a method is characterized in that the particle shape is spherical, the particle size is small, the hydrophobicity is high, the cohesiveness is small, and the specific gravity is small. In addition, there is an advantage that particles having a uniform particle size can be obtained. Therefore, paint, plastic,
It is also used as an additive for modifying rubber, cosmetics, and paper.

However, in such a production method, the organic group bonded to the silicon atom is limited to the methyl group, and the polyorganosilsesquioxane powder is obtained directly from the organotrialkoxysilane having an organic group other than the methyl group. However, it is not possible to obtain fine particles having a uniform particle size in good yield. Therefore, when trying to obtain a polyorganosilsesquioxane powder having an arbitrary high refractive index such that the transparency is maintained even when it is added to a transparent plastic having a high refractive index, or when it is added to a film, the film surface When trying to obtain a polyorganosilsesquioxane powder whose hardness is adjusted so that it will not be damaged even if it is rubbed,
Attempts to introduce groups other than methyl groups as some or all of the organic groups bonded to silicon atoms in the molecule have not been successful.

[0011]

DISCLOSURE OF THE INVENTION According to the present invention, polyorganosilsesquioxane fine particles in which a wide range of organic groups are bonded to silicon atoms, which are spherical and have a uniform particle size and whose particle size is extremely small. It aims at providing the manufacturing method of.

[0012]

The present invention has the general formula (I)

R ¹ Si (OR ² ) ₃ (I)

(Wherein R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group and R ² represents a substituted or unsubstituted alkyl group) in the presence of an organic acid. Hydrolyzed to give the general formula (II)

R ¹ Si (OH) ₃ (II)

A step of obtaining an organosilanetriol or a partial condensate thereof represented by the formula (wherein R ^{1 has} the meaning as described above), and then the organosilanetriol or a partial condensate thereof is treated with an aqueous alkali solution or an aqueous solution thereof. A method for producing polyorganosilsesquioxane fine particles, which comprises a step of causing a polycondensation reaction in a mixed solution of a solvent and an organic solvent.

The polyorganosilsesquioxane fine particles of the present invention are spherical and have a uniform particle size. The polyorganosilsesquioxane fine particles which can be newly produced by the present invention have an average particle diameter of 0.01 μm or more.

Examples of the group bonded to the silicon atom in the polyorganosilsesquioxane fine particles include a substituted or unsubstituted monovalent hydrocarbon group, and specifically, a methyl group and an ethyl group. An alkyl group such as a propyl group, a butyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group and a dodecyl group; a cycloalkyl group such as a cyclohexyl group; an aralkyl group such as a 2-phenylpropyl group; Aryl group such as phenyl group and tolyl group; Vinyl group, alkenyl group such as allyl group; and chloromethyl group, γ-chloropropyl group, γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3, Like 4-epoxycyclohexylethyl group, γ-mercaptopropyl group, 3,3,3-trifluoropropyl group It can be exemplified substituted hydrocarbon group, which no problem even in combination of two or more be used in one kind.

The manufacturing method of the present invention comprises two steps.

The first step of the production method of the present invention is to hydrolyze the organotrialkoxysilane represented by the general formula (I) in the presence of an organic acid to produce the organosilanetriol represented by the general formula (II). Alternatively, it is a step of obtaining a partial condensate thereof.

The substituted or unsubstituted monovalent hydrocarbon group represented by R ^{1 in} the general formula (I) is the same as the one bonded to the silicon atom of the polyorganosilsesquioxane fine particles as described above. A valent hydrocarbon group can be illustrated.

Among these groups, since it is possible to obtain spherical polyorganosilsesquioxane fine particles having a very small average particle size and a uniform particle size, methyl group, ethyl group and propyl group can be obtained. A group, a butyl group, a pentyl group, a hexyl group, a vinyl group or a phenyl group is preferable. In addition, it is possible to obtain spherical polyorganosilsesquioxane fine particles which are chemically stable and impart unique properties such as polarity due to a carbon functional group to the product, and further have a small particle size and are uniform. Therefore, a substituted propyl group such as γ-chloropropyl group, γ-methacryloxypropyl group, γ-glycidoxypropyl group; and 3,4-epoxycyclohexylethyl group are preferable. Among these groups, an epoxy ring-containing group such as γ-glycidoxypropyl group and 3,4-epoxycyclohexylethyl group is a catalyst for hydrolysis reaction, an organic acid or a polycondensation reaction catalyst. Due to the alkali
Some epoxy rings are opened, especially when ammonia is used as the latter catalyst, the ring-opening reaction produces a nitrogen-containing group, which does not impair the object of the present invention.

Examples of the substituted or unsubstituted alkyl group represented by R ^{2 in} the general formula (I) include an alkyl group such as methyl group, ethyl group, propyl group and butyl group; and methoxyethyl group, ethoxyethyl group, butoxy group. A substituted alkyl group such as an ethyl group can be exemplified. Among these, a methyl group and an ethyl group are preferable from the viewpoint of reaction rate,
A methyl group is particularly preferable.

Examples of the organotrialkoxysilane represented by the above general formula (I) include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltris (methoxyethoxy) silane, ethyltrimethoxysilane and vinyltrimethoxysilane. Methoxysilane, vinyltris (methoxyethoxy) silane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, 3,4-epoxycyclohexylethyltri Examples thereof include methoxysilane and γ-mercaptopropyltrimethoxysilane, and these may be used alone or in combination of two or more.

The hydrolysis reaction in the first step is carried out by bringing the organotrialkoxysilane and the organic acid into contact with each other by stirring, mixing or the like in an aqueous solution in which an organic acid serving as a catalyst is dissolved in excess water. To do.

As described above, using an organic acid as a catalyst has a high reaction rate and does not leave impurities such as ionic substances which limit the use of the finally obtained polyorganosilsesquioxane fine particles. Or, it is excellent because it is a small amount even if left. Examples of such an organic acid include formic acid, acetic acid, propionic acid, monochloroacetic acid, oxalic acid, citric acid, etc., but increase the reaction rate of hydrolysis with a small amount, and partial condensation of the produced polyorganosilanetriol. Formic acid and acetic acid are preferable because they suppress the reaction.

The amount of the organic acid used varies depending on the types of the silane and the organic acid, but it is 1 × 10 ^-3 to 1 part by weight with respect to 100 parts by weight of water used for hydrolyzing the organotrialkoxysilane. Is preferred and 5 × 10 ⁻³ or more
More preferably 0.1 part by weight. When it is less than 1 × 10 ⁻³ parts by weight, the reaction does not proceed sufficiently, and when it exceeds 1 part by weight, not only the concentration of acid groups in the impurities remaining in the system becomes high, but also the formed organo Silanetriol easily condenses.

The amount of water used for the hydrolysis reaction is preferably 2 to 10 mol per 1 mol of organotrialkoxysilane. When the amount of water is less than 2 mol, the hydrolysis reaction does not proceed sufficiently, and when it exceeds 10 mol, a partial condensate of organosilanetriol is precipitated.

The temperature at the time of hydrolysis is not particularly limited, and it may be carried out at room temperature or in a heated state, but in order to obtain the organosilanetriol in good yield, the reaction should be carried out at 5 to 60 ° C. Is preferred.

The second step of the production method of the present invention is a step of obtaining polyorganosilsesquioxane fine particles from the organosilanetriol obtained in the first step or a partial condensate thereof by a polycondensation reaction. The reaction of this second step is
It is carried out in an alkaline aqueous solution or a mixed solution of the alkaline aqueous solution and an organic solvent.

The alkali is such that its aqueous solution is basic, and acts as a neutralizing agent for the organic acid used in the first step and as a catalyst for the polycondensation reaction in the second step. Examples of such alkali include lithium hydroxide,
Examples thereof include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; ammonia; and organic amines such as monomethylamine and dimethylamine. Among these, ammonia and organic amines are preferable because they do not leave a trace amount of impurities that limit the use of polyorganosilsesquioxane fine particles, and ammonia is particularly preferable because it has low toxicity and is easy to remove. preferable.

Alkali is used as an aqueous solution because it is easy to handle and control the reaction.

The amount of the alkali used is such that it neutralizes the organic acid and effectively acts as a catalyst for the polycondensation reaction. For example, when ammonia is used as the alkali, water or a mixture of water and an organic solvent is used. 0.05 parts by weight or more is used with respect to parts by weight.

In the second step, it is preferable to use an organic solvent together with an aqueous alkali solution in order to obtain fine particles.

The organic solvent is preferably water-soluble, and includes methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, propylene glycol, ethylene glycol monoethyl ether, acetone, diethyl ether, tetrahydrofuran, Examples thereof include diacetone alcohol.

In the polycondensation reaction of the second step, an aqueous alkali solution or a mixed solution of the same and an organic solvent (hereinafter referred to as "alkaline solution") is charged into a reaction vessel, and then the reaction vessel is charged with the first step. An aqueous solution of the obtained organosilanetriol or a partial condensate thereof (hereinafter referred to as “silanol compound”) or a solution obtained by further diluting the aqueous solution of this silanol compound with water or the above organic solvent (hereinafter,
“Silanol solution”) is added and brought into contact with the alkaline solution.

The method of adding the silanol solution is not particularly limited. The addition rate of the silanol solution is not particularly limited,
For example, the optimum addition rate is determined by the type of silanol compound, the presence or absence of an organic solvent in the alkaline solution, and the type. For example, when the silanol solution is added to the alkaline aqueous solution, it is preferable that it takes 5 minutes or more.
More preferably, it takes 240 minutes. Further, when the silanol solution is added to the alkaline solution containing the organic solvent, it is preferable that the addition is performed within 5 minutes.

By carrying out the polycondensation reaction in this manner, the polyorganosilsesquioxane fine particles can be obtained as a dispersion or sol in water or a mixed liquid of water / organic solvent. The polyorganosilsesquioxane fine particles of the present invention can be used in the form of such a dispersion or sol, but if necessary, further subjected to appropriate treatment such as drying and crushing to obtain a fine powder. It can also be used.

The polyorganosilsesquioxane fine particles of the present invention thus obtained have a specific surface area (measured by the BET method) of about 100 to 1,000 m ² / g.

[0040]

According to the production method of the present invention, polyorganosilsesquioxane fine particles containing various organic groups, including those other than polymethylsilsesquioxane, which has been difficult to produce by conventional methods, can be obtained. With the composition according to the material composition ratio, the yield and the device efficiency can be obtained efficiently.

The polyorganosilsesquioxane fine particles obtained by the production method of the present invention are useful as fillers and additives for paints, plastics, rubbers, papers and the like.
In particular, it is suitable as a slipperiness improving agent for plastic films, a filler for transparent plastics, and a reinforcing agent.

Further, according to the present invention, it becomes possible to produce fine particles of polyorganosilsesquioxane in which various carbon-functional organic groups are bonded to silicon atoms. These polyfunctional compounds are produced by utilizing their carbon functionality. Can be used for surface modification treatment of

[0043]

EXAMPLES Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.
This will be described in more detail. In these examples, parts represent parts by weight.

Example 1 First Step Water 1 was added to a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer.
080 parts were charged, and 0.2 part of acetic acid was added to obtain a uniform solution. When this was stirred at 30 ° C. and 1,360 parts of methyltrimethoxysilane was added, the hydrolysis reaction proceeded, the temperature rose to 60 ° C. in 10 minutes, and a transparent reaction liquid was obtained. Then, stirring was continued for 4 hours and then filtration was performed to obtain a silanol solution.

Second step Water 2 is added to a reaction vessel equipped with a thermometer, a reflux condenser and a stirrer.
000 parts and 50 parts of 28% aqueous ammonia solution were taken, and the temperature was set to 25 ° C. While stirring this, 488 parts of the silanol solution obtained in the first step was added dropwise over about 10 minutes. After completion of dropping, stirring was continued for 16 hours. During the stirring, polymethylsilsesquioxane fine particles were deposited, and the reaction liquid changed to a milky white dispersion. This is put into a centrifuge to settle the fine particles and then taken out, and the temperature is 200 ° C.
When dried for 24 hours with a dryer of No. 1, 131 parts of white fine particles were obtained. This corresponds to a theoretical yield of 98% based on methyltrimethoxysilane.

When the fine particles were observed with an electron microscope, most of the particles were spherical, the maximum particle size was 0.3 μm, the minimum value was 0.05 μm, and the average particle size was 0.1 μm. there were.

The fine particles were placed in a magnetic crucible and the particles were placed in air for 9 minutes.
When it was heated to 00 ° C and pyrolyzed, the remaining amount was 89.0.
%Met. This is a value close to the theoretical amount of 89.6% when polymethylsilsesquioxane is oxidized and thermally decomposed into silicon dioxide. In addition, as a result of X-ray analysis of this thermal decomposition product,
It was confirmed to be amorphous silica. From this, it was confirmed that the white fine particles obtained were polymethylsilsesquioxane.

Examples 2-5 Using various organotrialkoxysilanes, acetic acid and water shown in Table 1, the reaction temperature was controlled at 30-40 ° C,
The first step was carried out in the same manner as in Example 1 except that the reaction time was 24 hours to obtain a silanol solution. This silanol solution was used in the amounts shown in Table 1, and the amounts of the aqueous ammonia solution and the water and the dropping time were changed as shown in Table 1, in the same manner as in Example 1, except that a methyl group and another hydrocarbon group were added to the silicon atom. Thus, polyorganosilsesquioxane fine particles bonded with were obtained. The yield, shape, particle size, and heating residue of the obtained fine particles are shown in Table 1.

The infrared spectroscopic analysis of the fine particles obtained in Example 3 was carried out by the KBr tablet method. FIG. 1 shows the spectrum. 1,000 to 1,160 cm ^-1 Si-O-Si
Absorption of bond, absorption of CH bond at 2,960 cm ^-1 , 1,
In addition to the absorption of methyl group of 265 cm ^-1 and 775cm ^-1,
3,055cm ^-1, 1,600cm ^-1, absorption is observed attributable to the phenyl group in 1,429Cm ^-1 and 700 cm ^-1.

[0050]

[Table 1]

Examples 6 to 9 In the same manner as in Example 1, polyorganosilsesquioxane fine particles in which a methyl group and a carbon functional group were bonded to a silicon atom were obtained under the conditions shown in Table 2. Table 2 shows each measurement result.

[0052]

[Table 2]

Example 10 900 parts of ethanol, 180 parts of water and 9 parts of 28% ammonia solution were placed in a reaction vessel equipped with a thermometer, a reflux device, a dropping device and a stirrer, and the temperature was set to 25 ° C. Then, 540 parts of the silanol solution obtained in the first step of Example 1 was added with stirring for about 10 seconds, and stirring was continued for another 30 seconds so that the system became uniform. Then, when the stirring was stopped and the system was left standing for 24 hours, the system exhibited a semitransparent gel state. The gel-like substance was taken out and dried to obtain polymethylsilsesquioxane fine particles.

When the particle size of the obtained fine particles was measured by a transmission electron microscope, the maximum value was 0.04 μm and the minimum value was 0.01 μm.

Infrared spectroscopic analysis of the fine particles obtained in Example 10 was carried out by the KBr tablet method. FIG. 2 shows the spectrum. 1,000 to 1,160 cm ^-1 Si-OS
absorption of i-bond, absorption of CH bond at 2,960 cm ⁻¹ ,
Absorption of methyl groups at 1,265 cm ^-1 and 775 cm ^-1 is seen.

An image of the fine particles obtained in Example 10 taken by a transmission electron microscope is shown in FIG.

Examples 11 to 14 Organic solvents were used in the same manner as in Example 10 except that the silanol solutions obtained in the first step of Examples 1, 3 and 7 were used, and the blending amounts shown in Table 3 were used. Polyorganosilsesquioxane fine particles were obtained by the combined use method. The particle size of the obtained fine particles was as shown in Table 3.

[0058]

[Table 3]

Examples 15 to 18 In the first step, the organic groups shown in Table 4 were used instead of acetic acid (Examples 15 to 17), or methyltris (methoxyethoxy) silane was used instead of methyltrimethoxysilane ( Example 18) Polymethylsilsesquioxane fine particles were obtained in the same manner as in Example 1 except for the above. The yield, shape, particle size, and heating residue of the obtained fine particles are shown in Table 4.

[0060]

[Table 4]

Comparative Example 1 Polyorgano was prepared in the same manner as in the second step of Example 2 except that a silanol solution was not prepared and a mixture of 68 parts of methyltrimethoxysilane and 99 parts of phenyltrimethoxysilane was added dropwise instead. Silsesquioxane fine particles were produced. In this case, when the alkoxysilane mixture was added dropwise and stirring was continued, it was observed that the system became milky white after about 10 minutes and particles were formed.
On the other hand, an oily substance settled at the bottom of the reaction vessel. When this oily substance was separated and analyzed, it was confirmed that most of it was unreacted phenyltrimethoxysilane.
As a result of infrared spectroscopic analysis, the produced white particles were polymethylphenylsilsesquioxane in which phenyl groups bonded to silicon atoms were slightly present. Further, the precipitated phenyltrimethoxysilane formed a gel-like mass due to the progress of the subsequent hydrolysis reaction and condensation reaction.

Comparative Example 2 Instead of the silanol solution obtained in the first step of Example 5, a mixture of 303 parts of methyltrimethoxysilane, 20.5 parts of hexyltrimethoxysilane and 40 parts of phenyltrimethoxysilane was used. Other than that, the polycondensation reaction was performed in the same manner as in the second step of Example 5. In this case, the entire amount of the alkoxysilane mixture was rapidly added, and the mixture was slowly stirred so as to maintain the two-layer state of the upper layer of the alkoxysilane layer and the lower layer of the aqueous ammonia solution layer. About 1 after addition
Phenyltrimethoxysilane was precipitated at the bottom of the reaction vessel in about 0 minutes, and an oily substance was confirmed on the wall surface of the reaction vessel. When this oily substance was taken out and analyzed, it was confirmed to be hexyltrimethoxysilane and its partial hydrolyzate. The precipitated phenyltrimethoxysilane became a gel-like mass due to the progress of the hydrolysis reaction and the condensation reaction over time, and the oily substance on the wall surface of the reaction vessel changed to an elastic gel-like substance.

[Brief description of drawings]

FIG. 1 is an IR spectrum of polyorganosilsesquioxane fine particles obtained in Example 3.

2 is an IR spectrum of polyorganosilsesquioxane fine particles obtained in Example 10. FIG.

FIG. 3 is a transmission electron micrograph showing a particle structure of polyorganosilsesquioxane fine particles obtained in Example 10.

Claims (2)

[Claims] 1. General formula (I) R ¹ Si (OR ² ) ₃ (I) (In the formula, R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group, and R ² represents a substituted or unsubstituted monovalent hydrocarbon group. An organotrialkoxysilane represented by (an alkyl group) is hydrolyzed in the presence of an organic acid to give a compound represented by the general formula (II) R ¹ Si (OH) ₃ (II) (wherein R ¹ has the above-mentioned meaning. To obtain an organosilanetriol or a partial condensate thereof represented by the following), and then subjecting the organosilanetriol or a partial condensate thereof to a polycondensation reaction in an aqueous alkali solution or a mixed solution of the aqueous solution and an organic solvent. A method for producing polyorganosilsesquioxane fine particles, comprising: 2. The method for producing polyorganosilsesquioxane fine particles according to claim 1, wherein R ¹ is an alkyl group having 6 or less carbon atoms, a vinyl group, a phenyl group, a substituted propyl group or a substituted cyclohexylethyl group.