WO2020133158A1

WO2020133158A1 - Method for preparing spherical silicone powder or agglomerates thereof, and spherical silicone powder or agglomerates thereof prepared thereby

Info

Publication number: WO2020133158A1
Application number: PCT/CN2018/124685
Authority: WO
Inventors: 陈树真; 李锐
Original assignee: 湖州五爻硅基材料研究院有限公司
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2020-07-02
Also published as: CN111868142B; CN111801369B; CN111868142A; WO2020134004A1; CN111801369A

Abstract

The present invention provides a method for preparing spherical silicone powder or agglomerates thereof, comprising the steps of: S1: providing an aqueous solution of an alkali metal salt of hydroxyl silicate; S2: adding acid or alkali, and finally regulating the PH of the aqueous solution to 7-13, so that the hydroxyl of silicic acid is condensed to obtain the spherical silicone powder or agglomerates thereof. The present invention also provides spherical silicone powder or agglomerates thereof obtained by the preparation method. According to the present invention, the problem of complex process or strict control in the prior art is avoided by preparing the spherical silicone powder or agglomerates thereof with the alkali metal salt of hydroxyl silicate. Specifically, according to the preparation method, the aqueous solution of the alkali metal salt of hydroxyl silicate itself is stable, and can be mixed with alkaline substances or tiny particles into composite particles, and thus has significant advantages.

Description

Method for preparing spherical silicone resin powder or its connecting body, and spherical silicone resin powder or its connecting body obtained thereby

Technical field

The present invention relates to silicone resin, and more particularly to a method for preparing spherical silicone resin powder or its connecting body and the spherical silicone resin powder or its connecting body obtained thereby.

Background technique

It is known that spherical silicone resin powder can be produced using methyltrimethoxysilane as a raw material. The synthesis method for preparing spherical silicone resin micropowder using methyltrimethoxysilane as raw material can refer to: "Spherical Silicone Micropowder", Huang Wenrun, Silicone Materials, 2007, 21(5)294-299; Japanese Patent P2001-192452A, P2002-322282A, JP-A 6-49209, JP-A 6-279589, P2000-345044A. Specifically, methyltrimethoxysilane is added on the aqueous phase containing ammonia water, and spherical silicone resin powder can be generated in the aqueous phase through the interface. But this synthesis method needs to control the oil-water interface, and the process is complicated. Another method of synthesizing spherical silicone resin powder is to first dissolve methyltrimethoxysilane in water under acidic conditions, and then add an alkaline substance to adjust the pH to alkaline to obtain spherical silicone resin powder. Since this synthesis method first dissolves methyltrimethoxysilane in acidic water, methylsilicic acid will condense under acidic conditions, and the molecular weight changes with time. Therefore, the time and temperature under acidic conditions must be strictly controlled to obtain Stable product. Moreover, since the existing synthesis method requires strict control of the interface, time, and temperature, it is impossible to compound the silicone resin powder with other organic or inorganic powders.

Summary of the invention

In order to solve the above-mentioned problems in the prior art, such as complicated process or strict control and inability to form composite particles, the present invention aims to provide a method for preparing spherical silicone resin powder or its connecting body and the spherical silicone resin powder obtained thereby Or its group.

The preparation method of the spherical silicone resin powder or its connecting group according to the present invention includes the steps of: S1, providing an aqueous solution of an alkali metal salt of a hydrocarbyl silicate; adding an acid or alkali to finally adjust the pH of the aqueous solution to 7-13 , So that the hydroxyl groups of silicic acid are condensed to obtain spherical silicone powder or its connecting group.

It should be understood that the bonding group here refers to an agglomerate formed by joining together at least two spherical silicone powders. For example, when two spherical silicone powders are joined together to form a peanut-shaped junction group, and three spherical silicone powders are joined together to form a zigzag junction...

The step S2 is to add acid to directly adjust the pH of the aqueous solution to 7-13, or add acid to adjust the pH of the aqueous solution to <7 (for example, adjust the pH to 5), and then add alkali to adjust the pH of the aqueous solution to 7-13. , So that the hydroxyl groups of silicic acid are condensed to obtain spherical silicone powder or its connecting group. Experiments show that, compared with the direct adjustment of the pH to 7-13, by adjusting the pH to <7 and then adjusting the pH to 7-13, the obtained spherical silicone resin powder or its connecting group has a larger diameter. For example, directly adjust the pH to 7-13, and the average particle size of the final spherical silicone powder is 1.6 microns, and adjust the pH to <7, and then adjust the pH to 7-13, the average particle size of the final spherical silicone powder. The diameter is 3.5 microns.

The hydrocarbon group is methyl, propyl, vinyl or phenyl.

In the step S1, an aqueous solution of the alkali metal salt of monohydrocarbyl silicate is prepared by using monohydrocarbyl trichlorosilane as a raw material. For example, after the reaction of a hydrocarbyl trichlorosilane and water, washing off hydrochloric acid to obtain a hydrosilicic acid, dissolving a hydrosilicic acid with an alkali metal hydroxide under a heating condition of 90-95 degrees to obtain an aqueous solution of a hydrocarbyl silicate alkali metal salt Solution. Preferably, the alkali metal hydroxide is sodium hydroxide or potassium hydroxide. For another example, monohydrocarbyl trichlorosilane reacts with alcohol at a low temperature to obtain acidic monohydrocarbyl silanol, which is mixed with alkali metal hydroxide, and the mixture is heated at 100-120 degrees to obtain an aqueous solution of monohydrocarbyl silicic acid alkali metal salt . Preferably, the alkali metal hydroxide is sodium hydroxide. For another example, monohydrocarbyl trichlorosilane is added dropwise to an aqueous solution of an alkali metal hydroxide to obtain a monohydrocarbyl silicate alkali metal salt solution. Preferably, the alkali metal hydroxide is sodium hydroxide or potassium hydroxide. Preferably, the mass fraction of the aqueous solution of sodium hydroxide is 5-15%.

In the step S1, an aqueous solution of the alkali metal salt of monohydrocarbyl silicate is prepared using monohydrocarbyl trimethoxysilane as a raw material. For example, monohydrocarbyl trimethoxysilane and sodium hydroxide solution react to obtain monohydrocarbyl sodium silicate. Preferably, the sodium hydroxide solution is a sodium hydroxide aqueous solution with a mass fraction of 5-15%. In a preferred embodiment, the sodium hydroxide solution is an aqueous solution of sodium hydroxide with a mass fraction of 10%.

Preferably, the solid content of the aqueous solution of the alkali metal salt of monohydrocarbyl silicate is 8-15%. In a preferred embodiment, the solids content is 13%. It should be understood that the solid content here refers to the mass percentage of the total amount of the remaining portion of the aqueous solution after drying.

In the step S2, the added acid is an inorganic acid or an organic acid, the base is an inorganic base or an organic base, and finally the pH of the aqueous solution is adjusted to 7.5-12, after stirring evenly, the stirring is stopped and allowed to stand, and then hydrochloric acid is added while stirring , Sulfuric acid, nitric acid, or acetic acid to adjust the pH to neutral and then filtered, washed with water, and dried to obtain spherical silicone resin powder or its connecting group. In a preferred embodiment, hydrochloric acid with a mass fraction of 5% is added to adjust the pH of the aqueous solution to 7.5-12. In a preferred embodiment, dilute hydrochloric acid with a mass fraction of 2-8% is added to adjust the pH to neutral. It should be understood that in step S2, the particle size of the aqueous solution is small when the pH is high, and the particle size is large when the pH value is low, and there is no special requirement for the temperature, and the particle generation rate is fast when the temperature is high. In addition, when the pH of the aqueous solution is adjusted to 7.5-10, especially when the pH is 9, the final result is mainly spherical silicone resin powder, and when the pH of the aqueous solution is adjusted to 10-12, especially when the pH is 12, What is finally obtained is the connecting body of spherical silicone resin powder.

Preferably, the aqueous solution of the alkali metal salt of monohydrocarbyl silicate provided in step S1 includes an organic solvent (such as an alcohol), so that the solubility of the alkali metal salt of monohydrocarbyl silicate is increased by adding alcohol to the aqueous solution. The added amount of alcohol is preferably less than 50% (the mass of alcohol is less than 50% of the mass of the aqueous solution), and too much will hinder the condensation of the hydroxyl group in step S2. Preferably, the amount of alcohol added is preferably less than 10%. In a preferred embodiment, 35 parts of methanol is added to 500 parts of sodium hydroxide aqueous solution. It should be understood that the aqueous solution may also be free of organic solvents and only an aqueous solution.

Preferably, the step S1 further includes combining an aqueous solution of a monohydrocarbyl silicate alkali metal salt with at least one silicic acid from an orthosilicic acid alkali metal salt, a dihydrocarbyl silicate alkali metal salt and a trihydrocarbyl silicate alkali metal salt Alkali metal salt mixed. Preferably, the aqueous solution of the alkali metal salt of monohydrocarbyl silicate includes at least one sodium silicate of sodium orthosilicate, dihydrocarbyl sodium silicate and trihydrocarbyl sodium silicate. In this way, by adding an alkali metal silicate salt to the aqueous solution, the properties of the spherical silicone resin powder or its contact group finally obtained are adjusted. Preferably, the amount of alkali metal silicate added is preferably less than 30% (the mass of the alkali metal silicate salt is less than 30% of the mass of the aqueous solution). For example, if too much sodium orthosilicate is added, the dielectric properties of the spherical silicone resin powder or its connecting body will be reduced. If too much sodium dimethyl silicate or trimethyl sodium silicate is added, it will make the spherical silicon The mechanical strength of the resin powder or its contact group decreases. In a preferred embodiment, 3 parts of sodium silicate are added to 500 parts of sodium methylsilicate aqueous solution.

Preferably, the step S1 further comprises mixing an aqueous solution of an alkali metal salt of a hydrocarbyl silicate with inorganic or organic nanoparticles. Preferably, the aqueous solution of the alkali metal salt of monohydrocarbyl silicate is mixed with at least one inorganic particle of nano titanium oxide and nano iron oxide. In this way, by adding the inorganic particles, the performance of the finally obtained composite particles is optimized. For example, the spherical silicon resin powder compounded with nanometer titanium oxide particles and silicone resin or its bonding group has ultraviolet absorption capability; and the spherical silicon resin powder compounded with nanometer iron oxide particles and silicon resin or its bonding group is magnetic. Preferably, a basic nano titanium oxide sol or a basic nano iron oxide sol is added to the aqueous solution of an alkali metal salt of monohydrocarbyl silicate. In a preferred embodiment, 100 parts of a basic nano titanium oxide sol or a basic nano iron oxide sol having a solid content of 20% is added to 500 parts of a sodium methyl silicate aqueous solution with a solid content of 15%. It should be understood that the solid content here refers to the mass percentage of the remaining part of the sol after drying in the total amount. Preferably, an aqueous solution of an alkali metal salt of monohydrocarbyl silicate is mixed with organic nanoparticles such as fumed silica. In this way, the performance of the composite particles finally obtained is optimized by the addition of organic particles. For example, the surface of spherical silica powder compounded with fumed silica and silicone resin has protrusions on the surface, and thus has a higher viscosity. It can be mixed with smooth spherical silicone resin powder or its junction group according to Viscosity compensation is required.

The invention also provides the spherical silicone resin powder obtained by the above-mentioned preparation method or its contact group. The spherical silicone resin powder or its connecting body can be used in the fields of light diffusion, anti-adhesion, lubrication and/or semiconductor packaging.

Preferably, the average particle diameter of the spherical silicone resin powder or its connecting body is 0.1-50 microns. In a preferred embodiment, the average particle diameter of the spherical silicone resin powder is 0.1-7 microns, and the average particle diameter of the spherical silicone resin powder is 10 microns.

According to the preparation method of the present invention, a spherical silicone resin powder or its connecting group is prepared by a monoalkyl silicate alkali metal salt. The aqueous solution of the monohydrocarbyl silicate alkali metal salt formed in step S1 is a stable solution. Silicone powder is easier to operate than traditional methods, and can be mixed with other alkaline substances such as sodium silicate, alkaline titanium oxide sol, alkaline silica sol, alkaline organic polymer emulsion, etc. without adding acid . In particular, according to the preparation method of the present invention, by adjusting the concentration of the aqueous solution of a monoalkyl silicate alkali metal salt, the particle size of the spherical silicone resin powder or its connecting group can be controlled. The higher the concentration of the aqueous solution, the larger the particle size of the obtained spherical silicone resin powder or its connecting body, and vice versa.

detailed description

In the following, preferred embodiments of the present invention will be given in conjunction with the drawings and described in detail.

Example 1

Based on the mass ratio, 35 parts of methanol was added to 500 parts of a 10% sodium hydroxide aqueous solution. While stirring, 55 parts of methyltrichlorosilane was added. After cooling, sodium chloride was removed by filtration to obtain a transparent solution. Hydrochloric acid with a mass fraction of 5% was added to the transparent solution to adjust the pH to 9, after stirring evenly, the stirring was stopped and allowed to stand for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder. The yield was 92%, and the average particle diameter observed by electron microscopy was 0.6 microns.

Example 2

Methyltrichlorosilane reacts with water to wash off hydrochloric acid to obtain methylsilicic acid. Sodium hydroxide is dissolved under a heating condition of 90 to 95 degrees to obtain methyl sodium silicate solution.

In terms of mass ratio, 500 parts of sodium methylsilicate aqueous solution with a solid content of 13% was added with 5% hydrochloric acid to adjust the pH to 12, after stirring evenly, the stirring was stopped and allowed to stand for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain a spherical silicone resin powder. The yield was 85%. The electron microscopic observation showed that the particle diameter of the single spherical silicone resin powder was 0.1 micrometer, and the diameter of the connection group was about 10 micrometer.

Example 3

In terms of mass ratio, 500 parts of sodium methylsilicate aqueous solution with a solid content of 13% was added with 5% hydrochloric acid to adjust the pH to 9, after stirring evenly, the stirring was stopped and allowed to stand for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder. The yield was 95%, and the average particle diameter observed by electron microscopy was 1.6 microns.

Example 4

In terms of mass ratio, 500 parts of sodium methylsilicate aqueous solution with a solid content of 13% was added with hydrochloric acid with a mass fraction of 5% to adjust the pH to 7.5. After stirring evenly, the stirring was stopped and allowed to stand for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder. The yield was 80%, and the average particle diameter observed by electron microscopy was 7 microns.

Example 5

In terms of mass ratio, add 3 parts of sodium orthosilicate to 500 parts of sodium methylsilicate aqueous solution with a solid content of 13%, add 5% of hydrochloric acid to adjust the pH to 9, stir evenly and stop stirring Set for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder. The yield was 82%, and the average particle diameter observed by electron microscopy was 0.8 microns.

Example 6

In terms of mass ratio, add 3 parts of sodium dimethylsilicate to 500 parts of sodium methylsilicate aqueous solution with a solid content of 13%, add 5% hydrochloric acid to adjust the pH to 9, stop after stirring evenly Stir for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder. The yield was 80%, and the average particle diameter observed by electron microscopy was 1.2 microns.

Example 7

In terms of mass ratio, 500 parts of sodium methylsilicate aqueous solution with a solid content of 15% were added with 100 parts of basic nano titanium oxide sol with a solid content of 20%, and hydrochloric acid with a mass fraction of 5% was added to adjust the pH to 12 After stirring, stop stirring and let stand for 1 hour. Dilute hydrochloric acid was added while stirring to adjust the pH to neutral, then filtered, washed with water, and dried to obtain spherical silicon resin titanium oxide composite powder. The yield was 90%, and the original particle size was observed to be 0.2 microns by electron microscopy. The particles are spherical, and contain nano titanium oxide. The resulting particles have ultraviolet light absorption capacity.

Example 8

In terms of mass ratio, 500 parts of sodium methylsilicate aqueous solution with a solid content of 15% were added with 100 parts of basic nano iron oxide sol with a solid content of 20%, and hydrochloric acid with a mass fraction of 5% was added to adjust the pH to 12 After stirring, stop stirring and let stand for 1 hour. Dilute hydrochloric acid was added while stirring to adjust the pH to neutral, then filtered, washed with water, and dried to obtain spherical silicon resin titanium oxide composite powder. The yield was 90%, and the original particle size was 0.5 microns as observed by electron microscopy. The particles are spherical, and contain nano-iron oxide. The resulting particles are magnetic.

Example 9

In terms of mass ratio, 500 parts of a sodium methylsilicate aqueous solution with a solid content of 15% was added with 10 parts of specific surface area 200 m ² /g of fumed silica, and then dispersed with a sand mill. Hydrochloric acid with a mass fraction of 5% was added to adjust the pH to 9, after stirring evenly, the stirring was stopped and allowed to stand for 1 hour. Dilute hydrochloric acid was added while stirring to adjust the pH to neutral, then filtered, washed with water and dried to obtain spherical silicon resin titanium oxide composite powder. The yield was 90%, and the average particle diameter was 0.8 microns as observed by electron microscopy. The shape of the particles is slightly spherical, with protrusions on the surface.

Example 10

In terms of mass ratio, add 50 parts of methanol to 500 parts of sodium methylsilicate aqueous solution with a solid content of 15%, add 5% hydrochloric acid to adjust the pH to 5 and then add 5% sodium hydroxide aqueous solution. The pH was adjusted to 9, after stirring, the stirring was stopped and allowed to stand for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder. The yield was 85%, and the average particle diameter observed by electron microscopy was 2 microns.

Example 11

In terms of mass ratio, add 50 parts of methanol to 500 parts of sodium methylsilicate aqueous solution with a solid content of 8%, add 5% hydrochloric acid to adjust the pH to 5 and then add 5% sodium hydroxide aqueous solution. The pH was adjusted to 9, after stirring, the stirring was stopped and allowed to stand for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder. The yield was 85%, and the average particle diameter observed by electron microscopy was 0.6 microns.

Example 12

In terms of mass ratio, 500 parts of sodium methylsilicate aqueous solution with a solid content of 13% was added with 5% hydrochloric acid to adjust the pH to 5 and then 5% sodium hydroxide aqueous solution was added to adjust the pH to 9. After stirring well, stop stirring and let stand for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder. The yield was 90%, and the average particle diameter was 3.5 microns as observed by electron microscopy.

Example 13

Methyltrimethoxysilane was added to the sodium hydroxide aqueous solution to prepare a sodium methylsilicate aqueous solution with a solid content of 10% of sodium methylsilicate.

In terms of mass ratio, 500 parts of sodium methylsilicate aqueous solution with a solid content of 10% was added with hydrochloric acid with a mass fraction of 5% to adjust the pH to 9, after stirring evenly, the stirring was stopped and allowed to stand for 1 hour. Add dilute hydrochloric acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder. The yield was 96%, and the average particle diameter observed by electron microscopy was 1.2 microns.

The above are only preferred embodiments of the present invention and are not intended to limit the scope of the present invention. The above embodiments of the present invention may also make various changes. That is, any simple, equivalent changes and modifications made according to the claims of the present application and the contents of the description fall within the scope of protection of the claims of the present invention patent. What is not described in detail in the present invention is conventional technical content.

Claims

A preparation method of spherical silicone resin powder or its connecting group, characterized in that the preparation method comprises the steps of:

S1, providing an aqueous solution of an alkali metal salt of a hydrocarbyl silicate;

S2, add acid or alkali, and finally adjust the pH of the aqueous solution to 7-13, so that the hydroxyl groups of the silicic acid are condensed to obtain a spherical silicone resin powder or its connecting group.
The preparation method according to claim 1, characterized in that, in the step S2, an acid is added to directly adjust the pH of the aqueous solution to 7-13, or an acid is added to adjust the pH of the aqueous solution to <7, and then an alkali is added to adjust the aqueous The pH of the solution reaches 7-13, so that the hydroxyl groups of the silicic acid are condensed to obtain spherical silicone resin powder or its connecting group.
The preparation method according to claim 1, wherein the hydrocarbon group is methyl, propyl, vinyl or phenyl.
The preparation method according to claim 1, characterized in that, in the step S1, an aqueous solution of the monohydrocarbyl silicate alkali metal salt is prepared using monohydrocarbyl trichlorosilane as a raw material.
The preparation method according to claim 1, characterized in that, in the step S1, an aqueous solution of the alkali metal salt of monohydrocarbyl silicate is prepared using monohydrocarbyl trimethoxysilane as a raw material.
The preparation method according to claim 1, wherein in the step S2, the added acid is an inorganic acid or an organic acid, the base is an inorganic base or an organic base, and finally the pH of the aqueous solution is adjusted to 7.5-12, After stirring evenly, stop stirring and let stand, then add hydrochloric acid, sulfuric acid, nitric acid, or acetic acid while stirring to adjust the pH to neutral, then filter, wash with water, and dry to obtain spherical silicone resin powder or its connecting group.
The preparation method according to claim 1, wherein the aqueous solution of the alkali metal salt of monohydrocarbylsilicate provided in step S1 further includes an organic solvent.
The preparation method according to claim 1, characterized in that the step S1 further comprises combining an aqueous solution of an alkali metal salt of a hydrocarbyl silicate with an alkali metal salt of orthosilicate, an alkali metal salt of a dihydrocarbyl silicate, and a trihydrocarbyl silicon At least one alkali metal salt of silicate is mixed with the acid alkali metal salt.
The preparation method according to claim 1, wherein the step S1 further comprises mixing an aqueous solution of an alkali metal salt of a hydrocarbyl silicate with inorganic or organic nanoparticles.
A spherical silicone resin powder or its connecting group, characterized in that the spherical silicone resin powder or its connecting group is obtained according to the preparation method according to any one of claims 1-9.
The spherical silicone resin powder or its contact group according to claim 10, wherein the average particle diameter of the spherical silicone resin powder or its contact group is 0.1-50 microns.