PREPARATION METHOD FOR SPHERICAL SILICA POWDER FILLER, POWDER FILLER OBTAINED THEREBY AND USE THEREOF

Abstract

A preparation method for a spherical silica powder filler comprises the following steps: S1, providing spherical polysiloxane comprising a T unit by means of a hydrolysis condensation reaction of R.sub.1SiX.sub.3, wherein R.sub.1 is hydrogen atom or an organic group having independently selectable 1 to 18 carbon atoms, X is a hydrolyzable group, and T unit is R.sub.1SiO.sub.3—; and S2, calcining the spherical polysiloxane under the condition of a dry oxidizing gas atmosphere, the calcining temperature being between 850° C. and 1200° C., so as to obtain the spherical silica powder filler which does not contain silica particles of which the diameter is less than 50 nanometers. The spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers, has a low dielectric loss and a low thermal expansion coefficient, and is suitable for high-frequency high-speed circuit boards, prepregs or copper clad laminates, etc.

Claims

1. A preparation method for a spherical silica powder filler, comprising the following steps: S1, providing spherical polysiloxane comprising a T unit by means of a hydrolysis condensation reaction of R.sub.1SiX.sub.3, wherein R.sub.1 is hydrogen atom or an organic group having independently selectable 1 to 18 carbon atoms, X is a hydrolyzable group, and T unit is R.sub.1SiO.sub.3—; and S2, calcining the spherical polysiloxane under a condition of a dry oxidizing gas atmosphere, the calcining temperature being between 850° C. and 1200° C., so as to obtain the spherical silica powder filler which does not contain silica particles of which the diameter is less than 50 nanometers.

2. The preparation method according to claim 1, wherein the hydrolyzable group is an alkoxy group or a halogen atom.

3. The preparation method according to claim 1, wherein a speed of the hydrolysis condensation reaction is controlled to prevent from generating the polysiloxane particles of which the diameter is less than 50 nanometers.

4. The preparation method according to claim 1, wherein the oxidizing gas contains oxygen to oxidize all the organics in the polysiloxane.

5. The preparation method according to claim 1, wherein the calcining temperature is between 850° C. and 1100° C., and the calcining time is between 6 hours and 12 hours.

6. The preparation method according to claim 1, wherein the spherical polysiloxane further comprises a Q unit, a D unit, and/or a M unit, wherein Q unit is SiO.sub.4—, D unit is R.sub.2R.sub.3SiO.sub.2—, M unit is R.sub.4R.sub.5R.sub.6SiO—, wherein each of R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6 is a hydrogen atom or an hydrocarbon group having independently selectable 1 to 18 carbon atoms.

7. The preparation method according to claim 1, wherein the preparation method further comprises adding a treatment agent to perform surface treatment on the spherical silica powder filler, and the treatment agent comprises a silane coupling agent and/or disilazane; the silane coupling agent is (R.sub.7).sub.a(R.sub.8).sub.bSi(M).sub.4-a-b, wherein each of R.sub.7, R.sub.8 is a hydrogen atom, an hydrocarbon group having independently selectable 1 to 18 carbon atoms, or an hydrocarbon group having independently selectable 1 to 18 carbon atoms replaced by a functional group, wherein the functional group is selected from at least one of the following organic functional groups: vinyl, allyl, styryl, epoxy group, aliphatic amino, aromatic amino, methacryloxypropyl, acryloyloxypropyl, ureidopropyl, chloropropyl, mercaptopropyl, polysulfide group, isocyanate propyl; M is an alkoxy group with 1 to 18 carbon atoms or a halogen atom, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, a+b is 1, 2 or 3; and the disilazane is (R.sub.9R.sub.10R.sub.11)SiNHSi(R.sub.12R.sub.13R.sub.14), wherein each of R.sub.9, R.sub.10, R.sub.11, R.sub.12, R.sub.13, R.sub.14 is a hydrogen atom or an hydrocarbon group having independently selectable 1 to 18 carbon atoms.

8. A spherical silica powder filler obtained according to the preparation method of claim 1, wherein the spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers, and an average particle size of the spherical silica powder filler is between 0.1 μm and 5 μm.

9. A use of the spherical silica powder filler according to claim 8, wherein the spherical silica powder filler of different particle sizes is tightly packed and graded in resin to form a composite material, which is suitable for circuit board material and semiconductor packaging material.

10. The use according to claim 9, wherein coarse particles above 1 μm, 3 μm, 5 μm, 10 μm, or 20 μm in the spherical silica powder filler are removed by a dry or wet sieving or inertial classification.

11. A spherical silica powder filler obtained according to the preparation method of claim 2, wherein the spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers, and an average particle size of the spherical silica powder filler is between 0.1 μm and 5 μm.

12. A spherical silica powder filler obtained according to the preparation method of claim 3, wherein the spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers, and an average particle size of the spherical silica powder filler is between 0.1 μm and 5 μm.

13. A spherical silica powder filler obtained according to the preparation method of claim 4, wherein the spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers, and an average particle size of the spherical silica powder filler is between 0.1 μm and 5 μm.

14. A spherical silica powder filler obtained according to the preparation method of claim 5, wherein the spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers, and an average particle size of the spherical silica powder filler is between 0.1 μm and 5 μm.

15. A spherical silica powder filler obtained according to the preparation method of claim 6, wherein the spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers, and an average particle size of the spherical silica powder filler is between 0.1 μm and 5 μm.

16. A spherical silica powder filler obtained according to the preparation method of claim 7, wherein the spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers, and an average particle size of the spherical silica powder filler is between 0.1 μm and 5 μm.

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 are listed as follows.

[0020] The average particle size is measured with HORIBA's laser particle size distribution analyzer LA-700.

[0021] The presence or absence of silica particles of which the diameter is less than 50 nanometers is directly observed with a field emission scanning electron microscope (FE-SEM). When no spherical silica particle of which the diameter is less than 50 nanometers is substantially observed in random ten photos of 20,000 magnifications, the spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers.

[0022] The dielectric loss test method comprises: mixing different volume fractions of sample powders and paraffin to make test samples, and using a commercially available high-frequency dielectric loss meter to measure the dielectric loss under the condition of 10 GHz. Then the dielectric loss of the sample is obtained from the slope in the coordinate, wherein the ordinate represents the dielectric loss, and the abscissa represents the volume fraction. The dielectric losses of the Examples and Comparative Examples of the present invention at least can be relatively compared although it is generally difficult to obtain the absolute value of the dielectric loss.

[0023] In this text, “degrees” refers to Celsius degrees, i.e., ° C.

[0024] In this text, the average particle size refers to the volume average diameter of the particles.

Embodiment 1

[0025] Deionized water of a certain weight at room temperature was added into a reactor with a stirrer. While stirring, methyltrimethoxysilane of 80 by weight was added and a small amount of acetic acid was added to adjust the pH to about 5. After the methyltrimethoxysilane was dissolved, 5% ammonia water of 25 by weight was added and stirred for 10 seconds, and then the stirring was stopped. After standing for 1 hour, it was filtered and dried to obtain spherical polysiloxane. The polysiloxane powder was put into a muffle furnace and dry air was introduced for calcination. The final calcining temperature was 850 degrees, 1000 degrees or 1100 degrees, and the calcining time was 12 hours. The analysis results of the samples were listed in following Table 1.

TABLE-US-00001 TABLE 1 Silica Average Final Particle of Deionized Particle Calcining Diameter Dielectric Water by Size Temperature less than Loss Weight (μm) (° C.) 50 nm (10 GHz) Example 1 1500 0.8 1000 None 0.00005 Example 2 1100 1.2 1100 None 0.00003 Example 3 800 3.0 850 None 0.00008 Example 4 600 4.5 1100 None 0.00002

Embodiment 2

[0026] Deionized water of 1100 by weight at room temperature was added into a reactor with a stirrer. While stirring, propyltrimethoxysilane of 80 by weight was added and a small amount of acetic acid was added to adjust the pH to about 5. After the propyltrimethoxysilane was dissolved, 5% ammonia water of 25 by weight was added and stirred for 10 seconds, and then the stirring was stopped. After standing for 1 hour, it was filtered and dried to obtain spherical polysiloxane. The polysiloxane powder was put into a muffle furnace and dry air was introduced for calcination. The final calcining temperature was 950 degrees, and the calcining time was 6 hours. The analysis result of the sample was listed in following Table 2.

TABLE-US-00002 TABLE 2 Average Final Calcining Silica Particle Dielectric Particle Temperature of Diameter less Loss Size (μm) (° C.) than 50 nm (10 GHz) Example 5 0.6 950 None 0.00006

Embodiment 3

[0027] Deionized water of 2500 by weight at 40° C. was added into a reactor with a stirrer. While stirring, methyltrimethoxysilane of 80 by weight was added and a small amount of acetic acid was added to adjust the pH to about 5. After the methyltrimethoxysilane was dissolved, 5% ammonia water of 60 by weight was added and stirred for 10 seconds, and then the stirring was stopped. After standing for 1 hour, it was filtered and dried to obtain spherical polysiloxane. The polysiloxane powder was put into a muffle furnace and dry air was introduced for calcination. The final calcining temperature was 1000 degrees, and the calcining time was 12 hours. The analysis result of the sample was listed in following Table 3.

TABLE-US-00003 TABLE 3 Average Final Calcining Silica Particle Dielectric Particle Temperature of Diameter less Loss Size (μm) (° C.) than 50 nm (10 GHz) Example 6 0.15 1000 None 0.00009

Embodiment 4

[0028] Deionized water of 5000 by weight at 70° C. was added into a reactor with a stirrer. While stirring, methyltrimethoxysilane of 80 by weight was added and a small amount of acetic acid was added to adjust the pH to about 5. After the methyltrimethoxysilane was dissolved, 5% ammonia water of 200 by weight was added and stirred for 1 hour. It was filtered and dried to obtain spherical polysiloxane. The polysiloxane powder was put into a muffle furnace and dry air was introduced for calcination. The final calcining temperature was 1000 degrees, and the calcining time was 12 hours. The analysis result of the sample was listed in following Table 4.

TABLE-US-00004 TABLE 4 Average Final Calcining Silica Particle Dielectric Particle Temperature of Diameter less Loss Size (μm) (° C.) than 50 nm (10 GHz) Comparative 0.30 1000 Exist 0.00025 Example 1

Embodiment 5

[0029] The crushed silica with an average particle size of 2 μm was sent to a spheroidizing furnace with a flame temperature of 2500 degrees for melting and spheroidizing. All the spheroidized powders were collected as sample of Comparative Example 2. The analysis result of the sample was listed in following Table 5.

TABLE-US-00005 TABLE 5 Average Silica Particle Dielectric Particle of Diameter less Loss Size (μm) than 50 nm (10 GHz) Comparative 3.0 Exist 0.001 Example 2

[0030] It should be understood that the samples obtained in the Examples 1-6 may be surface-treated. Specifically, vinyl silane coupling agent, epoxy silane coupling, disilazane, etc. can be used to treat the samples as required. Also, at least two treatment agents can be used to treat the samples as required.

[0031] It should be understood that coarse particles above 1 μm, 3 μm, 5 μm, 10 μm, or 20 μm in the spherical silica powder filler are removed by a dry or wet sieving or inertial classification.

[0032] It should be understood that the spherical silica powder filler of different particle sizes is tightly packed and graded in resin to form a composite material.

[0033] 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.