Tokuyama Corporation

Kenichi Ishizu

Tadaharu Komatsubara

Hiroshi Kato

Hiroaki Taira

Takayuki Maehara

Yuya Yamano

Makoto Sato

Kenji Fukunaga

Hiroyuki Kono

Yohei Chikashige

Yoshinori Tagashira

Provided are a poly alkylsilsesquioxane fine particle having hydrophobicity and having a small particle diameter, an external additive for toner and a dry toner for electrophotography each using the same, and a method of manufacturing a hydrophobized spherical polyalkylsilsesquioxane fine particle. The hydrophobized spherical poly alkylsilsesquioxane fine particle has a mass-based median diameter in a centrifugal sedimentation method within the range of from 0.05 &#x3bc;m to 0.3 &#x3bc;m. The fine particle is produced through, for example, at least a process involving: mixing a raw material solution prepared using an alkyl trialkoxysilane with an alkaline aqueous medium to obtain a polycondensation reaction liquid; mixing the polycondensation reaction liquid with an aqueous solution to obtain a fine particle dispersion liquid; and blending a hydrophobizing agent in the fine particle dispersion liquid.

Hydrophobized spherical polyalkylsilsesquioxane fine particle, external additive for toner, dry toner for electrophotography, and method of manufacturing hydrophobized spherical polyalkylsilsesquioxane fine particle

The present invention relates to a method for producing inorganic oxide particles, comprising at least the following steps of: The inorganic oxide particles obtained by the method of the present invention have high purity and are excellent in flowability.

Method for producing inorganic oxide particles

Provided is a cationic polymer-modified silica dispersion which comprises silica fine particles having an average particle diameter of less than 200 nm and a cationic polymer and which does not bring about coagulation of the silica particles. The above dispersion which is diluted to a solid concentration of 1.5% by weight is characterized by having a light scattering index (n value) of 2.0 or more. The above dispersion can be produced by oppositely-colliding a mixed solution obtained by mixing silica with a cationic polymer in a polar solvent at a treating pressure of 300 kgf/cm or more or passing it through an orifice under a condition that a pressure difference between the inlet side and the outlet side of the orifice is 300 kgf cm or more.

Cationic polymer-modified silica dispersion and production process for the same

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Shunan, Japan

Kenichi Ishizu