Tokuyama Corporation

Hiromasa Fujioka

Hiroaki Taira

Osamu Tanaka

Naoki Mikami

Toshiaki Ootani

This surface-treated sol-gel silica is characterized by containing sol-gel silica having an average particle size of 0.05 μm or more and 2.0 μm or less as measured by laser diffraction scattering and a surface treatment agent on the surface of the sol-gel silica. In a dispersion produced by dispersing 5 mass % of the sol-gel silica in ethanol by emitting ultrasonic waves at 40W for 10 minutes, the content of particles with particle sizes of 5 μm or more is 10 ppm or less in a particle number size distribution obtained by a Coulter counter method.

Surface-treated sol-gel silica and method for producing same

Composite oxide fine particles are produced by sol-gel method under conditions in which coarse particles and aggregated particles are unlikely to be generated, and the composite oxide fine particles are further wet-filtered using a filter to remove the coarse particles and the aggregated particles. Then, a salt is added to a dispersion of the composite oxide fine particles to produce weak aggregates of the composite oxide fine particles in the dispersion. A solid content is separated from the dispersion of the composite oxide fine particles containing the aggregates, and then dried. The solid content is easily made finer because no firm aggregates are generated during the drying. That is, composite oxide fine particles containing no coarse particles and aggregated particles are obtained. Use of a known cracking means can further reduce the amount of coarse particles.

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Shunan, Japan

Hiromasa Fujioka