JPS6377940A - Perfectly spherical polymethylsilsesquioxane powder and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title powder which has excellent uniformity in particle shape and a large quantity of contact charge, by carrying out hydrolysis and condensation of the interface between an upper layer contg. a methyltrialkoxysilane (a condensate of its partial hydrolyzate), etc., and a lower layer contg. as aq. soln. of NH3 or an amine, etc. CONSTITUTION:A mixture (A) of a methyltrialkoxysilane obtd. by alkoxylating methyltrichlorosilane with an alcohol, a condensate of its partial hydrolyzate and optionally an org. solvent and an aq. soln. (B) obtd. by dissolving NH3 or amines as a catalyst in an amount sufficient to neutralize chlorine atoms of the component A in a mixture of water with 0-20wt% org. solvent are put into a container in such a manner that two layers composed of an upper layer consisting of the component A and a lower layer consisting of the component B are formed. They are stirred at a stirring speed of 2-100rpm to carry out gradually hydrolysis and condensation at the interface between the components A and B. The formed spherical particles is allowed to move into the lower layer to obtain the title powder having the shape of an independent, perfectly spherical particle, a narrow particle size distribution such that the average particle size is + or -30% and the quantity of contact charge of -200--2,000muC/g.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a polymethylsilsesquioxane powder and a method for producing the same, and more specifically, the present invention relates to a polymethylsilsesquioxane powder and a method for producing the same. The present invention relates to a large true spherical polymethylsilsesquioxane powder and a method for producing the same.

[Technical background of the invention and its problems] It has been known that polymethylsilsesquioxane 17 can be produced by hydrolyzing and condensing a trifunctional silane such as methyltrichlorosilane. for example,
Belgian Patent No. 572,412 discloses that methyltrichlorosilane is hydrolyzed in a spray or dropped into a large amount of water with stirring to be hydrolyzed to obtain solid polymethylsilsesquioxane. The method is described.

However, this method generates a large amount of heat during the hydrolysis reaction,
In addition to the problem of corrosion of the equipment due to large amounts of hydrogen chloride as a by-product, by-product hydrogen chloride and unhydrolyzed methyltrichlorosilane remain in the polymethylsilsesquioxane produced, and a relatively large amount of chlorine atoms remain. It had the disadvantage of remaining. Furthermore, this method had the disadvantage of low production efficiency because it used a large amount of water.

As a method to eliminate the above drawbacks, JP-A-54-7230
In Publication No. 0, the amount of chlorine is 0.1 to 5.0% by weight,
A method is disclosed in which methyltrialkoxysilane and/or a partial hydrolyzate thereof is hydrolyzed and condensed in an aqueous solution containing an alkaline earth metal hydroxide or an alkali metal carbonate.

However, in this method, relatively large amounts of alkaline earth metals remain in the polymethylsilsesquioxane powder produced, so when used as fillers for various synthetic resins, it tends to absorb moisture. In addition, in this method, the amount of chlorine in the raw material methyl 1-realkoxysilane and/or its partial hydrolyzate was adjusted to 0.1 to 5.0.
There was also a point where adjustments had to be made to a heavy ■%.

The present inventor first prepared a methyl[-realkoxysilane and/or a partially hydrolyzed condensate thereof with a sufficient amount to neutralize the chlorine atoms present in the silane and/or partially hydrolyzed condensate thereof. The above-mentioned problems were solved by hydrolysis and condensation in an aqueous solution of parent ammonia or amine in a catalytic amount, and 1q of polymethylsilsesquioxane with excellent free-flowing properties was obtained. (Japanese Patent Application Laid-open No. Sho GO-13813). Through this method, a new usefulness of polymethylsilsesquioxane as an organic powder was discovered, but it is necessary to impart qualities such as particle shape as an organic powder, and improvements are desired. Ta.

[Objective of the Invention] An object of the present invention is to provide a polymethylsilsesquioxane powder having quality characteristics such as uniformity of particle shape and extremely large amount of contact charge, and a method for producing the same.

[Structure of the Invention] As a result of extensive research in order to obtain polymethylsilsesquioxane with such excellent quality characteristics, the present inventor has discovered that
We have discovered that such polymethylsilsesquioxane powder can be obtained by setting appropriate stirring conditions when performing a hydrolysis/condensation reaction of methyltrialkoxysilane in an aqueous solution of ammonia or amine, and hereby we have developed a polymethylsilsesquioxane powder. He came up with an invention.

That is, in the present invention, methyltrialkoxysilane and/or a partially hydrolyzed condensate thereof or a mixture of methyltrialkoxysilane and/or a partially hydrolyzed condensate thereof and an organic solvent is formed as an upper layer, and aqueous solutions of ammonia or amines are used. And/or a mixture of ammonia or amine and an organic solvent is used as the lower layer, and methyltrialkoxysilane and/or its partially hydrolyzed condensate is hydrolyzed and condensed at the interface of these, so that the particle shapes are independent of each other. Almost perfectly spherical, particle size distribution is ±3 of the average particle diameter.
polymethylsilsesquioxane powder which is in the range of 0%! It is characterized by being A-built.

The raw material methyltrialkoxysilane and its partially hydrolyzed condensate in the present invention may be, for example, methyltrichlorosilane alkoxylated with a suitable alcohol by a known method. Depending on the type of alcohol used in the alkoxylation reaction, methyltrimethoxysilane, methyltrialkoxysilane, methyltripropoxysilane, methyltributoxysilane, etc. can be obtained from this methyltrialkoxysilane, and methyltrialkoxysilane can be completely removed. A partially hydrolyzed condensate of methyltrialkoxysilane obtained by the presence of a smaller amount of water than the theoretical amount required for hydrolysis may also be used. Among these methyltrialkoxysilanes, methyltrimethoxysilane is preferably used from the viewpoint of production efficiency.

In the present invention, the chlorine atoms present as by-product hydrogen chloride or unreacted methylchlorosilane in the methyltrialkoxysilane obtained by the alkoxylation reaction or its partially hydrolyzed condensate are not particularly limited. do not have.

Ammonia or amines in the present invention are a neutralizing agent for the chlorine atoms remaining in methyltrialkoxysilane, and a catalyst for the hydrolysis/condensation reaction of methyltrialkoxysilane. Examples of the amines include monomethylamine, dimethylamine, monomethylamine, diethylamine, and ethylenediamine.

As the ammonia or amines used in the present invention, ammonia is advantageous because it has low toxicity, is easy to remove, and is inexpensive, and generally commercially available aqueous ammonia solutions (concentration 28%) can be used.

The amount of ammonia and amines used is a sufficient amount to neutralize the chlorine atoms present in methyltrialkoxysilane or its partially hydrolyzed condensate, plus a catalytic amount, but removal etc. Therefore, it should be kept to the minimum necessary. If the amounts of ammonia and amines used are too small, the hydrolysis of the alkoxysilanes and even the condensation reaction will not proceed, making it impossible to obtain the desired product.

Ammonia or amines are used as an aqueous solution or a mixed solution of water and an organic solvent.

Examples of this organic solvent include alcohols such as methanol, ethanol, propyl alcohol, n-butanol, and 1so-butanol; ketones such as dimethyl ketone, methyl ethyl ketone, and acetone; aliphatic hydrocarbon solvents; Examples include aromatic hydrocarbon solvents. When an aromatic hydrocarbon solvent such as 1 to toluene or xylene is used, it is mixed uniformly with methyltrialkoxysilane and/or its partially hydrolyzed condensate.

The amount of organic solvent added is not particularly limited, but it is preferably 20 parts by weight or less per 100 parts by weight of the total amount of water and organic solvent.

The amount of the aqueous solution of ammonia and amines to be used should be at least twice the theoretical maximum amount necessary to hydrolyze the alkoxy group of methyltrialkoxysilane or its partially hydrolyzed condensate, or the chlorine atom of unreacted chlorosilane. It is sufficient that the amount contains 100% of water. In particular, there is no upper limit to the amount of the aqueous solution of the amines mentioned above.

However, when the amount of the aqueous solution used increases, it is disadvantageous in terms of the reaction process and the reaction time becomes longer. On the other hand, if the usage rate is too low, the hydrolysis reaction will be inhibited by the alcohol by-produced, resulting in a long reaction time, and the object of the present invention having a substantially perfect spherical shape will not be obtained.

The hydrolysis/condensation reaction for producing 1 q of substantially spherical polymethylsilsesquioxane powder in the present invention is carried out as follows.

That is, an aqueous solution of ammonia or amines or a mixed solution of ammonia or amines in water and an organic solvent (hereinafter referred to as an alkaline solution) is placed in a container equipped with a stirring blade.

) and methyltrialkoxysilane and/or its partially hydrolyzed condensate so as to form a two-layered state with an alkaline solution layer in the lower layer and a methyl 1-alkoxysilane and/or its partially hydrolyzed condensate layer in the upper layer. Prepare. Next, the two-layer solution is stirred at an appropriate stirring speed to gradually carry out a hydrolysis/condensation reaction between the methyltrialkoxysilane and the alkaline solution at the interface. As the reaction progresses, spherical particles are produced and migrate to the lower alkaline solution layer, and the lower layer turns milky white.

The stirring conditions in this reaction vary depending on the shape of the stirring blade, the composition of the alkaline solution, etc., but in order to obtain the target particles that are perfectly spherical and have a narrow particle size distribution, stirring conditions of 2 to 100 r.
It is preferable to carry out the reaction at a speed of about 1.0 m, more preferably at a speed of about 5 to 5 or m. If the stirring speed is too high, the methyltrialkoxysilane and/or its partially hydrolyzed condensate before reaction will be drawn into the alkaline solution, and the hydrolysis/condensation reaction will occur rapidly in the alkaline solution, resulting in particles adhering. Resulting in. Also, if the stirring speed is too low, particles generated by interfacial reaction will
It is difficult to disperse in the alkaline solution in the lower layer, and it settles and aggregates into lumps.

Further, the temperature of this hydrolysis/condensation reaction is not particularly limited, but should be adjusted to be below the boiling point of methyltrialkoxysilane. For example, in the case of methyltrimethoxysilane, it is preferable to carry out the reaction at 50'C or less.

Under the above conditions, the reaction is carried out until the upper methyltrialkoxysilane layer disappears, and stirring is continued.

The time and temperature of this stirring are determined by the r! Although it varies depending on the A-forming mother, etc., about 1 to 10 hours is appropriate, and the temperature may be raised to about 50'C if necessary.

Next, the dispersion is filtered through a wire mesh, dehydrated by centrifugal separation or centrifugal filtration, and the resulting paste is dried by heating at 100 to 220°C, and then decomposed using a jet mill or the like. By crushing, a polymethylsilsesquioxane powder, at least 95% of which is approximately spherical and has a contact charge of -200 to -2000 μC/g, can be obtained.

[Effects of the Invention - Production of the Invention] By the method described above, a truly spherical polymethylsilsesquioxane powder can be obtained for the first time. The true spherical polymethylsilsesquioxane powder referred to as '*''I in the present invention can be used as a filler J) for synthetic resins and as an additive, for example, as an agent for imparting smoothness to synthetic resin films, paper, etc., and as an agent for imparting mold release properties. used as.

In particular, since the particle size division is extremely narrow, the above-mentioned effect can be
It is suitable for applications where the thickness of the thin film of dripping paint is carefully controlled to +Hf.

Furthermore, since the amount of contact charge is large, it is possible to adjust the amount of charge of young bodies of different species by adding a small amount.

[Examples] Examples of the present invention will be described below. Note that all parts in the examples indicate small mother parts.

First, water and an ammonia aqueous solution with a concentration of 28% are stirred in a container at the ratio shown in Table 1, and the ammonia aqueous solutions A1 to A
I got 4. Note that the numbers indicating the blending amounts in the table represent parts. (The same applies hereinafter.) Table 1 Example 1 4000 parts of ammonia aqueous solution A1 was placed in a 4-hour flask equipped with a thermometer, reflux device, and stirrer, and 100 r.
The mixture was stirred for 10 minutes at p and m to form a homogeneous ammonia aqueous solution. In this ammonia aqueous solution, chlorine atom-substituted C1ff1
Add 600 parts of 10 ppm methyltrimethoxysilane to the ammonia aqueous solution while turning the stirrer for 5R, P, and A to avoid mixing. state. Next, the stirring speed of the stirrer was set to 2 Or, p, m to allow the hydrolysis/condensation reaction to proceed at the interface between methyltrimethoxysilane and ammonia aqueous solution while maintaining a two-layer state. As the reaction progressed, the reactants gradually settled to the lower layer, and the lower layer became cloudy due to floating reactants, and the upper methyltrimethoxysilane layer gradually became thinner and disappeared visually in about 3 hours. . Further, the temperature was maintained at 50 to 60°C, and stirring was performed under the same conditions for 3 hours, followed by cooling to 25°C. Then, the precipitated product was
After filtration through a mesh wire mesh, it was dehydrated by centrifugation to form a cake, and this cake layer was dried in a drying dish at 200°C. This was crushed using a lab jet to obtain a white powder.

When the polymethylsilsesquioxane powder thus obtained was observed with an electron microscope, it was found that the particle size was Xl! 1I
It has an almost perfect spherical shape with a ratio of il to Y axis of 1.0 to 1.2, and an average particle diameter of about 1.9 μm (1.7 to 2.1 μm
). Further, the contact charge amount was measured by a blow-off method using a contact charge measurement device (Toshiba Chemical Co., Ltd. (m'A)), and the result was -1000 μC/g.

Examples 2 to 5 Hydrolysis and condensation reactions of methyltrimethoxysilane were carried out under the same conditions as in Example 1 except for the formulation shown in Table 2 and the stirring speed during the reaction. A lean powder was obtained.

Comparative Examples 1 to 2 For comparison with the present invention, as Comparative Example 1, the stirring speed was increased so that the methyl 1 to rimethoxysilane layer and the ammonia aqueous solution layer were mixed, and methyl Hydrolysis and condensation reactions of trimethoxysilane were carried out. In addition, as Comparative Example 2, the lj2 stirring speed was decreased so that the products in the middle of the reaction settled and accumulated at the bottom of the lower layer, and the second
Hydrolysis and condensation reactions of methyltrimethoxysilane were carried out using the formulations shown in the table. As shown in Table 2, each polymethylsilsesquioxane powder obtained as described above has 3
3 Boil.

(Left below) a! Table 2 Examples 6 to 8 Aqueous ammonia solution and organic solvent of m shown in Table 3 were placed in the flask used in Example 1. 1001·, p, m
After stirring for 10 minutes to make it homogeneous, 600 parts of methyltrimethoxysilane was added in the same manner as in Example 1, and the reaction was carried out under the same conditions as in Example 1 except that the stirring speed was 15 r, I), m, Almost spherical polymethylsilsesquioxane powders not shown in Table 3 were obtained.

Example 9 The reaction was carried out under the same conditions as in Example 6, except that toluene was used as an organic solvent by mixing it with methyltrime-1-hexysilane in advance to obtain almost perfectly spherical polymethylsilsesquioxane powder shown in Table 3. Ta.

(Margin below) Table 3

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of one embodiment of the present invention, and the reference drawing is an enlarged photograph of one embodiment of the present invention. Applicant Toshiba Silicone Co., Ltd. Representative Patent Attorney Satoshi Suyama - Figure 1 Procedure Amendment: l! iF (Fang Shuo 1, Th matter) A Japanese Patent Application No. 1983-221520 2, Title of the invention: True spherical polymethylsilsesquioxane powder and its manufacturing method 3, Person making the amendment Relationship with the case/Patent applicant Toshiba Silicone Co., Ltd. 4, Agent 2-1 Kanda Tamachi, Chiyoda-ku, Tokyo November 25, 1986 (Shipping date) Enlarged photo of an embodiment of the present invention" is deleted. that's all

Claims (4)

[Claims] (1) A polymethylsilsesquioxane powder characterized in that each particle has an independent, almost perfect spherical shape, and a particle size distribution is within ±30% of the average particle diameter. (2) The polymethylsilsesquioxane powder according to claim 1, which has a contact charge amount of -200 to -2000 μC/g. (3) Methyltrialkoxysilane and/or its partially hydrolyzed condensate or a mixture of methyltrialkoxysilane and/or its partially hydrolyzed condensate and an organic solvent as the upper layer, and ammonia or an aqueous solution of amine and/or ammonia Or a true spherical polymethylsilsesquioxane characterized by using a mixture of an amine and an organic solvent as the lower layer, and hydrolyzing and condensing methyltrialkoxysilane and/or its partially hydrolyzed condensate at the interface between these layers. Method of manufacturing powder. (4) The method for producing true spherical polymethylsilsesquioxane powder according to claim 3, wherein the methyltrialkoxysilane is methyltrimethoxysilane.