Tokuyama Corporation

Masahiro Nakamura

Tadaharu Komatsubara

Ryuji Ishimoto

Yuya Yamano

A silicone oil-treated silica particle according to the present invention includes a silica particle body and silicone oil. The silica particle body has a BET specific surface area of 70 m/g to 120 m/g. The silica particle body has been surface-treated with the silicone oil. The amount of free silicone oil liberated from the surface of the silica particle body in the silicone oil accounts for 2.0 mass % to 5.0 mass % with respect to the silica particle body. A surface-treated styrene acrylic resin particle, in which 2 parts by mass of the silicone oil-treated silica particle has been added to 100 parts by mass of a styrene acrylic resin particle having a particle size median of 5 &#x3bc;m to 8 &#x3bc;m, has a degree of agglomeration of 18% or less.

Silicone oil-treated silica particles and toner for electrophotography

To reduce scratches during polishing while ensuring an appropriately high polishing rate, provided are a silica for CMP satisfying the following (A) to (C), an aqueous dispersion using a silica for CMP, and a method of producing a silica for CMP: (A) a BET specific surface area of 40 m/g or more and 180 m/g or less; (B) a particle density measured by a He-gas pycnometer method of 2.24 g/cmor more; and (C) a coefficient of variation in primary particle diameter calculated by TEM/image analysis of 0.40 or less.

Growing community of inventors

Yamaguchi, Japan

Masahiro Nakamura