Method of preparing silica composite particles

1. A method of preparing silica composite particles, comprising:

treating silica particles,

wherein the treating is for treating the silica particles with a metal compound in which a metal atom binds to an organic group via an oxygen atom, in supercritical carbon dioxide, and

the metal atom is selected from a group consisting of Ti, Al, Zr, V, and Mg.

2. The method of preparing silica composite particles according to claim 1 ,

wherein the metal atom is Ti or Al.

3. The method of preparing silica composite particles according to claim 1 , further comprising:

treating the surface of the silica particles of which the surface has been treated with the metal compound, with a hydrophobizing agent.

4. The method of preparing silica composite particles according to claim 1 ,

wherein the silica particles are prepared by a sol-gel method.

5. The method of preparing silica composite particles according to claim 1 ,

wherein an amount of the metal compound added is from 0.01% by weight to 10% by weight based on the silica particles.

6. The method of preparing silica composite particles according to claim 1 ,

wherein in the treating, the temperature of the supercritical carbon dioxide is from 80° C. to 300° C.

7. The method of preparing silica composite particles according to claim 1 ,

wherein a volume average particle diameter of the silica particles is from 10 nm to 500 nm.

8. The method of preparing silica composite particles according to claim 1 ,

wherein a circularity of the silica particles is from 0.5 to 0.85.

9. The method of preparing silica composite particles according to claim 1 ,

wherein a density of the supercritical carbon dioxide is in a range of from 0.10 g/ml to 0.80 g/ml.

10. A method of preparing silica composite particles, comprising:

preparing a silica particle dispersion that contains silica particles and a solvent containing alcohol and water;

removing the solvent from the silica particle dispersion by injecting supercritical carbon dioxide;

treating the surface of the silica particles having undergone the solvent removal, in the supercritical carbon dioxide by using a metal compound in which a metal atom selected from a group consisting of Ti, Al, Zr, V, and Mg binds to an organic group via an oxygen atom; and

treating the surface of the silica particles treated with the metal compound, in the supercritical carbon dioxide with a hydrophobizing agent.

11. The method of preparing silica composite particles according to claim 10 ,

wherein the metal atom is Ti or Al.

12. The method of preparing silica composite particles according to claim 10 ,

wherein the silica particles are prepared by a sol-gel method.

13. The method of preparing silica composite particles according to claim 10 ,

wherein an amount of the metal compound added is from 0.01% by weight to 10% by weight based on the silica particles.

14. The method of preparing silica composite particles according to claim 10 ,

wherein in the treating, a temperature of the supercritical carbon dioxide is from 80° C. to 300° C.

15. The method of preparing silica composite particles according to claim 10 ,

wherein a volume average particle diameter of the silica particles is from 10 nm to 500 nm.

16. The method of preparing silica composite particles according to claim 10 ,

wherein a circularity of the silica particles is from 0.5 to 0.85.