| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of producing hydrophobic silica particles having high hydrophobicity and significantly reduced moisture absorptivity. SOLUTION: The method of producing hydrophobic silica particles, the hydrophobic silica particles comprising silica as a base material, is characterized in that: the silica has a content of isolated silanol groups of 0.01 to 0.3 mmol/m<SP>2</SP>, and the ratio of specific surface areas (Ss/Ss<SB>0</SB>) of a specific surface area Ss to a theoretical surface area Ss<SB>0</SB>defined by formula of Ss<SB>0</SB>(m<SP>2</SP>/g)=6/(ρ×d), satisfies not more than 2, whereinρrepresents true specific gravity of silica and d represents an average (μm) of the primary particle diameter of the silica; and an organosilylating agent is made to react with the silica. The silica is preferably produced by a production method including: a step of preparing silica having a controlled content of isolated silanol groups and a specific surface area into respective specified ranges by firing silica particles obtained through a hydrolysis-condensation reaction of alkoxysilane at 650 to 1,180°C; and a step of introducing an organosilyl group to the silica. COPYRIGHT: (C)2011,JPO&INPIT
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