CN111320754B

CN111320754B - Preparation method of spherical polysiloxane

Info

Publication number: CN111320754B
Application number: CN202010306019.4A
Authority: CN
Inventors: 陈树真; 李锐; 丁烈平; 唐成; 沈海斌
Original assignee: Zhejiang Sanshi New Material Technology Co Ltd
Current assignee: Zhejiang Sanshi New Material Technology Co., Ltd
Priority date: 2020-04-17
Filing date: 2020-04-17
Publication date: 2021-06-25
Anticipated expiration: 2040-04-17
Also published as: CN111320754A

Abstract

The invention relates to a preparation method of spherical polysiloxane, which comprises the following steps: s1, mixing alkyl trialkoxy silane with water, adding acid to adjust the mixture to be acidic to obtain transparent solution, and mixing alkaline substances with water to obtain alkaline solution; and S2, simultaneously adding the transparent solution and the alkaline solution into a mixing container, stirring and mixing, stopping stirring after mixing, wherein the stirring time is shorter than 0.5 minute, and standing to obtain the spherical polysiloxane with the average particle size of less than 1 micron. According to the preparation method of the spherical polysiloxane, the spherical polysiloxane with narrow particle size distribution is obtained.

Description

Preparation method of spherical polysiloxane

Technical Field

The invention relates to spherical polysiloxane, in particular to a preparation method of spherical polysiloxane.

Background

The spherical polysiloxane can be used as a filler for high-frequency and high-speed circuit boards with low dielectric constant and low dielectric loss requirements, a filler for semiconductor packaging materials, a light diffusion agent, cosmetics, an anti-sticking agent and the like. The spherical polysiloxane can be calcined to obtain the spherical silicon dioxide. The synthetic spherical silicon dioxide has the characteristics of high purity, small specific surface area, narrow particle size distribution, no coarse particles and the like, and can be widely used as high-grade filler for high-speed circuit boards, semiconductor packaging, film opening agents, cosmetics, rubber plastic products and the like.

There are various methods for producing spherical polyorganohydrocarbylsiloxanes, one of which is to hydrolyze a monohydroxytrialkoxysilane (e.g., methyltrimethoxysilane) under acidic conditions with water to give a transparent aqueous solution, then to adjust the pH to alkaline by adding an alkaline substance to the aqueous solution under stirring, and then to stand to obtain spherical polysiloxanes, see JP3970449B 2. The polysiloxane formation mechanism of this method is that the hydrolysis product of the monohydroxytrihydrocarbyloxysilane is condensed under alkaline conditions to form a liquid polysiloxane having a relatively low degree of crosslinking. Since the surface tension liquid polysiloxane forms spherical droplets in the aqueous phase, the spherical droplets collide and combine in the aqueous phase to cause particle size growth. As the degree of crosslinking increases, the particles become solid and spherical polysiloxane particles are finally formed. Therefore, when spherical silicone having an average particle diameter (volume average diameter) of 1 μm or less is produced by this method, it is necessary to increase the pH to accelerate the solidification of the silicone. However, when the production quantity is enlarged, the volume of the aqueous phase to be mixed becomes large, so that polysiloxane is formed in a local region during uniform mixing after the alkali liquor is added, and the particle size distribution of finally formed spherical polysiloxane is wide.

Disclosure of Invention

The invention provides a preparation method of spherical polysiloxane, aiming at solving the problem of preparing spherical polysiloxane with wider particle size distribution by using alkyl trialkoxysilane.

The preparation method of the spherical polysiloxane comprises the following steps: s1, mixing alkyl trialkoxy silane with water, adding acid to adjust the mixture to be acidic to obtain transparent solution, and mixing alkaline substances with water to obtain alkaline solution; and S2, simultaneously adding the transparent solution and the alkaline solution into a mixing container, stirring and mixing, stopping stirring after mixing, wherein the stirring time is shorter than 0.5 minute, and standing to obtain the spherical polysiloxane with the average particle size of less than 1 micron.

Preferably, 99% of the particles of the spherical polysiloxane are within the range of the average particle diameter. + -. 0.2. mu.m.

Preferably, 80% of the particles of the spherical polysiloxane are within the range of the average particle diameter. + -. 0.1. mu.m.

Preferably, the monohydroxytrialkoxysilane is methyltrimethoxysilane and the spherical polysiloxane is spherical polymethylsiloxane.

Preferably, the step of preparing a clear solution comprises: adding methyltrimethoxysilane and acetic acid into deionized water, and stirring until the methyltrimethoxysilane is dissolved to obtain a transparent solution. In a preferred embodiment, 650 weight parts of deionized water are added with 80 weight parts of methyltrimethoxysilane and 1 weight part of 5% acetic acid, and stirred until the methyltrimethoxysilane is dissolved to obtain a transparent solution.

Preferably, the step of preparing the alkaline solution comprises: mixing deionized water and ammonia water to obtain alkaline solution. In a preferred embodiment, 650 parts by weight of deionized water and 100 parts by weight of 5% ammonia water were mixed to obtain an alkaline solution.

Preferably, in step S2, the transparent solution and the alkaline solution are simultaneously added to the mixing container by the metering pump.

Preferably, in step S2, the PH of the mixed solution is greater than 10.

Preferably, in step S2, after standing for 30 minutes or more, the mixture is filtered and dried to obtain spherical polysiloxane powder.

Preferably, in step S2, the transparent solution and the alkaline solution are continuously and simultaneously added into the mixing container to be mixed by stirring, after mixing, the stirring is stopped and the solution is continuously discharged into a storage tank to be left to stand.

According to the preparation method of the spherical polysiloxane, the spherical polysiloxane with narrow particle size distribution is obtained.

Drawings

FIG. 1 is a graph showing a distribution of particle sizes of spherical polymethylsiloxanes obtained in example 1 and comparative example 1.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

650 parts by weight of deionized water were added with 80 parts by weight of methyltrimethoxysilane and 1 part by weight of 5% acetic acid, and stirred until methyltrimethoxysilane was dissolved to obtain a transparent solution.

650 parts by weight of deionized water and 100 parts by weight of 5% aqueous ammonia were mixed to obtain an alkaline solution.

The clear solution and the alkaline solution were added simultaneously to the mixing vessel with the stirrer switched on, mixed with stirring, and the mixing was completed within 0.5 minutes. Standing for more than 30 minutes, filtering and drying to obtain the spherical polymethylsiloxane powder. The slurry with pH value more than 10 before filtration can be directly measured for the particle size distribution, and the result of the powder particle size distribution is shown in figure 1, wherein 99% of the particles are between 0.5 μm and 0.8 μm, particularly 80% of the particles are between 0.65 μm and 0.75 μm, and the particle size distribution is narrow.

Comparative example 1

Adding 80 parts by weight of methyltrimethoxysilane and 1 part by weight of 5% acetic acid into 1300 parts by weight of deionized water, stirring until the methyltrimethoxysilane is dissolved to obtain a transparent solution, then adding 100 parts by weight of 5% ammonia water into the transparent solution while stirring, and completing the mixing within 1 minute. Standing for more than 30 minutes, filtering and drying to obtain the spherical polymethylsiloxane powder. The particle size distribution of the slurry before filtration can be directly measured, and the result of the powder particle size distribution is shown in figure 1, wherein 99% of the particles are between 0.4 μm and 1.8 μm, particularly 80% of the particles are between 0.8 μm and 1 μm, and the particle size distribution is wide.

Example 2

The clear solution and the alkaline solution of example 1 were continuously fed into a mixing vessel by a metering pump, mixed and continuously discharged into a storage tank. Standing for more than 30 minutes, filtering and drying to obtain the spherical polymethylsiloxane powder.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.

Claims

1. A method for preparing spherical polysiloxane, which is characterized by comprising the following steps:

s1, mixing 80 parts by weight of methyltrimethoxysilane and 650 parts by weight of deionized water, adding 1 part by weight of 5% acetic acid to adjust the mixture to be acidic to obtain a transparent solution, and mixing 100 parts by weight of 5% ammonia water and 650 parts by weight of deionized water to obtain an alkaline solution;

and S2, simultaneously adding the transparent solution and the alkaline solution into a mixing container which starts a stirrer, stirring and mixing, stopping stirring after mixing, wherein the stirring time is shorter than 0.5 minute, and after standing, obtaining slurry with the pH value of more than 10, wherein the average particle size of spherical polysiloxane in the slurry is less than 1 micron, 99% of the particles of the spherical polysiloxane are between 0.5 and 0.8 microns, and 80% of the particles are between 0.65 and 0.75 microns.

2. The method according to claim 1, wherein the transparent solution and the alkaline solution are simultaneously added to the mixing vessel by a metering pump in step S2.

3. The production method according to claim 1, wherein in step S2, the polysiloxane powder is obtained by standing for 30 minutes or more, filtering, and drying.

4. The method according to claim 1, wherein in step S2, the transparent solution and the alkaline solution are continuously and simultaneously added into a mixing vessel and mixed by stirring, and after mixing, the stirring is stopped and the solution is continuously discharged into a storage tank and allowed to stand.