Method For Preparing Spherical Silica Powder Filler, And Resulting Spherical Silica Powder Filler And Application Thereof

Abstract

The present invention relates to a method for preparing a spherical silica powder filler, comprising the following steps: performing hydrolytic condensation on an organic silicon compound to obtain polysiloxane precipitate, wherein the organic silicon compound comprises silane having the chemical formula of (R.sub.1).sub.a(R.sub.2).sub.b(R.sub.3).sub.cSi(X).sub.d, wherein R.sub.1, R.sub.2, and R.sub.3 are independently selected C1-18 hydrocarbyl groups or hydrogen atoms; X is a hydrolysable functional group; a, b, and c are 0, 1, 2, or 3; d is 1, 2, 3, or 4; and a+b+c+d=4; smashing and drying the polysiloxane precipitate to obtain siloxane angular powder; and melting and spherifying the siloxane angular powder into the spherical silica powder filler. The present invention also provides a spherical silica powder filler obtained by the method and an application thereof. The present invention takes the organic silicon compound as the starting material, and the resulting spherical silica powder filler does not contain radioactive elements such as uranium and thorium, and therefore, the requirement of low radioactivity is satisfied.

Claims

1. A method for preparing a spherical silica powder filler, comprising the following steps: S1, performing hydrolytic condensation on an organic silicon compound to obtain polysiloxane precipitate, wherein the organic silicon compound comprises silane having the chemical formula of (R.sub.1).sub.a(R.sub.2).sub.b(R.sub.3).sub.cSi(X).sub.d, wherein R.sub.1, R.sub.2, and R.sub.3 are independently selected C1-18 hydrocarhyl groups or hydrogen atoms; X is a hydrolysable functional group; a, h, and c are 0, 1, 2, or 3; d is 1, 2, 3, or 4; and a+b+c+d=4; S2, smashing and drying the polysiloxane precipitate to obtain siloxane angular powder; and S3, melting and spherifying the siloxane angular powder into the spherical silica powder filler.

2. The method according to claim 1, wherein the organic silicon compound further comprises silica with a uranium content of not more than 1 ppb.

3. The method according to claim 1, wherein the polysiloxane precipitate is smashed with a high-speed shearer to obtain a slurry of polysiloxane powder, and the slurry is filtered, washed with deionized water to neutrality, and then dried to obtain the siloxane angular powder.

4. The method according to claim 1, wherein the siloxane angular powder is melted and spheroidized after removing of organic component in polysiloxane.

5. The method according to claim 4, wherein the temperature for removing of organic component in polysiloxane is 400° C.-600° C.

6. The method according to claim 1, wherein the siloxane angular powder is thrown into a burner with a flame temperature of 2000 degrees or more to perform melt and spheroidization.

7. The method according to claim 1, wherein coarse oversize particles above 1, 3, 5, 10, 20, 45, 55 or 75 microns in the spherical silica powder filler are removed by a dry or wet sieving or inertial classification.

8. The method according to claim 1, wherein the spherical silica powder filler has a uranium content of not more than 1 ppb.

9. The method according to claim 1, wherein the spherical silica powder filler has an average particle size of 0.1-70 microns.

10. The method according to claim 9, wherein the spherical silica powder filler of different particle sizes is tightly packed and graded in resin to form a composite material.

11. The method according to claim 10, wherein the composite material is suitable for semiconductor packaging materials, circuit boards and intermediate semi-finished products thereof.

Description

DESCRIPTION OF THE ENABLING EMBODIMENT

[0018] The preferred embodiments of the present invention are given below and described in detail.

[0019] The detection methods involved in the following embodiments include:

[0020] The average particle size was measured by a laser particle size distribution instrument HORIBA LA-700, and the solvent was isopropanol.

[0021] The content of uranium was measured by Agilent 7700X ICP-MS. The sample was prepared by total dissolution in hydrofluoric acid after burning at 800 degrees.

[0022] Embodiment 1

[0023] 100 parts by weight of methyltrichlorosilane was added dropwise to 1000 parts by weight of deionized water while stirring to obtain a white precipitated methylsiloxane polymer. The precipitate was smashed with a high-speed shearer to obtain a slurry of methylsiloxane polymer powder with an average particle size of 5 microns. The slurry was filtered, washed with deionized water to neutrality, and then dried at 120 degrees for 3 hours to obtain a methylsiloxane angular powder with an average particle size of 5 microns. The powder was heated to remove of organic component in polysiloxane under different temperature and time conditions, and then sent into a burner with a flame temperature of 2000 degrees or more to perform melt and spheroidization. All the powders were collected with a dust bag to obtain a spherical silica powder sample. The analysis results of the samples were listed in Table 1. The spherical silica of Example 1 without removing of organic component in polysiloxane was brown, and the ones with removing of organic component in polysiloxane were all white spherical silica.

TABLE-US-00001 TABLE 1 Average Temperature Time for Average Uranium Particle for Removing Removing Particle Content Size of of organic of organic Size of of Polysiloxane component in component in Spherical Spherical Powder polysiloxane polysiloxane Silica Silica μm ° C. hours μm ppb Example 5 without  6* <0.3 1 removing of organic component in polysiloxane Example 5 400 24 6 <0.3 2 Example 5 450 6 6 <0.3 3 Example 5 500 4 6 <0.3 4 Example 5 600 4 6 <0.3 5 *The color of the powder is brown.

[0024] Embodiment 2

[0025] 100 parts by weight of methyltrichlorosilane was added dropwise to 1000 parts by weight of deionized water while stirring to obtain a white precipitated methylsiloxane polymer. The precipitate was smashed with a high-speed shearer to obtain a slurry of methylsiloxane polymer powder with different average particle sizes. The slurry was filtered, washed with deionized water to neutrality, and then dried at 120 degrees for 3 hours to obtain a methylsiloxane angular powder. The powder was heated to remove of organic component in polysiloxane at 450 degrees for 6 hours, and then sent into a burner with a flame temperature of 2000 degrees or more to perform melt and spheroidization. All the powders were collected with a dust bag to obtain a spherical silica powder sample. The analysis results of the samples were listed in Table 2.

TABLE-US-00002 TABLE 2 Average Temperature Time for Average Uranium Particle for Removing Removing Particle Content Size of of organic of organic Size of of Polysiloxane component in component in Spherical Spherical Powder polysiloxane polysiloxane Silica Silica μm ° C. hours μm ppb Example 0.3 450 6 0.5 <0.3 6 Example 1 450 6 1.8 <0.3 7 Example 10 450 6 10 <0.3 8 Example 30 450 6 29 <0.3 9 Example 70 450 6 67 <0.3 10

[0026] Embodiment 3

[0027] A mixture of 80 parts by weight of methyltrichlorosilane, 10 parts by weight of tetrachlorosilane, 5 parts by weight of dimethyldichlorosilane and 5 parts by weight of trimethylchlorosilane was added dropwise to 1000 parts by weight of deionized water while stirring to obtain a white precipitated methylsiloxane polymer. The precipitate was smashed with a high-speed shearer to obtain a slurry of methylsiloxane polymer powder with an average particle size of 5 microns. The slurry was filtered, washed with deionized water to neutrality, and then dried at 120 degrees for 3 hours to obtain a methylsiloxane angular powder with an average particle size of 5 microns. The powder was heated to remove of organic component in polysiloxane at 450 degrees for 6 hours, and then sent into a burner with a flame temperature of 2000 degrees or more to perform melt and spheroidization. All the powders were collected with a dust bag to obtain a spherical silica powder sample. The analysis results of the sample were listed in Table 3.

TABLE-US-00003 TABLE 3 Average Temperature Time for Average Uranium Particle for Removing Removing Particle Content Size of of organic of organic Size of of Polysiloxane component in component in Spherical Spherical Powder polysiloxane polysiloxane Silica Silica μm ° C. hours μn ppb Example 5 450 6 6 0.5 11

[0028] Embodiment 4

[0029] 100 parts by weight of methyltrichlorosilane containing oligomers was added dropwise to 1000 parts by weight of deionized water while stirring to obtain a white precipitated methylsiloxane polymer. The precipitate was smashed with a high-speed shearer to obtain a slurry of methylsiloxane polymer powder with an average particle size of 5 microns. The slurry was filtered, washed with deionized water to neutrality, and then dried at 120 degrees for 3 hours to obtain a methylsiloxane angular powder with an average particle size of 5 microns. The powder was heated to remove of organic component in polysiloxane at 450 degrees for 6 hours, and then sent into a burner with a flame temperature of 2000 degrees or more to perform melt and spheroidization. All the powders were collected with a dust bag to obtain a spherical silica powder sample. The analysis results of the sample were listed in Table 4.

TABLE-US-00004 TABLE 4 Average Temperature Time for Average Uranium Particle for Removing Removing Particle Content Size of of organic of organic Size of of Polysiloxane component in component in Spherical Spherical Powder polysiloxane polysiloxane Silica Silica μm ° C. hours μm ppb Example 5 450 6 6 0.7 12

[0030] Embodiment 5

[0031] A mixture of 90 parts by weight of methyltrichlorosilane and 10 parts by weight of fumed silica was added dropwise to 1000 parts by weight of deionized water while stirring to obtain a white precipitated methylsiloxane polymer. The precipitate was smashed with a high-speed shearer to obtain a slurry of methylsiloxane polymer powder with an average particle size of 5 microns. The slurry was filtered, washed with deionized water to neutrality, and then dried at 120 degrees for 3 hours to obtain a methylsiloxane angular powder with an average particle size of 5 microns. The powder was heated to remove of organic component in polysiloxane at 450 degrees for 6 hours, and then sent into a burner with a flame temperature of 2000 degrees or more to perform melt and spheroidization. All the powders were collected with a dust bag to obtain a spherical silica powder sample. The analysis results of the sample were listed in Table 5.

TABLE-US-00005 TABLE 5 Average Temperature Time for Average Uranium Particle for Removing Removing Particle Content Size of of organic of organic Size of of Polysiloxane component in component in Spherical Spherical Powder polysiloxane polysiloxane Silica Silica μm ° C. hours μm ppb Example 5 450 6 6 0.9 13

[0032] The foregoing description refers to preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Various changes can be made to the foregoing embodiments of the present invention. That is to say, all simple and equivalent changes and modifications made in accordance with the claims of the present invention and the content of the description fall into the protection scope of the patent of the present invention. What is not described in detail in the present invention is conventional technical content.