SLICA FINE PARTICLES

摘要

Silica fine particles which can be obtained by a reaction in a flame and have an average particle size of 0.05-1 mum, characterized in that a fractal shape parameter alpha1 within an analyzing range of 50 nm-150 nm and a fractal shape parameter alpha2 within an analyzing range of 150 nm-353 nm when measured by a small-angle X-ray scattering satisfy the conditions shown by the following expressions (1) and (2) -0.0068S + 2.548 <= ALPHA1 <= -0.0068S + 3.748 (1) -0.0011S + 1.158 <= ALPHA2 <= -0.0011S + 2.058 (2), where S in the expressions (1) and (2) denotes the BET specific surface area (m<2>/g) of silica fine particles. The silica fine particles can be highly compactly filled without increasing viscosity when they are used as a filling material for semiconductor sealing resin, as well as used as an abrasive and a filling material for an ink jet sheet coat layer or the like, can favorably express strength in an obtained molding when used as a resin filler, and can impart a good fluidity to toner and deliver a good coming-off preventing feature to toner resin particles when used as an electrophotographic toner external additive.