Tokuyama Corporation

Osamu Tanaka

Hiroaki Taira

Hiromasa Fujioka

Masao Ariyuki

Mari Aoki

Toshiaki Ootani

Kazuhiro Fukunaga

Naoki Mikami

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

Amorphous silica-titania composite oxide powder is powder untreated with a surface treatment agent and consisting of amorphous silica-titania composite oxide particles, wherein: a refractive index at a measurement wavelength of 589 nm is not less than 1.46; a volume-based cumulative 50% diameter is 0.1 μm to 2.0 μm; and a content of particles having a particle size of not less than 5.0 μm is not more than 10 ppm, and wherein, in a case where the powder is dried in an atmospheric air at 110° C. for 12 hours, and powder thus dried is stored for 24 hours at a temperature of 25° C. and a relative humidity of 85% so as to absorb moisture, a water absorption rate is not more than 0.8% by mass as calculated from a mass X before moisture absorption and a mass Y after the moisture absorption in accordance with the formula: (Y−X)/X×100.

Amorphous silica-titania composite oxide powder, resin composition, liquid dispersion, and method for producing silica-coated silica-titania composite oxide powder

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.

Composite oxide powder and method for production thereof

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Shunan, Japan

Osamu Tanaka