| 摘要 |
This invention provides flame-generated fine silica particles having an average particle size of 0.05 to 1 mum, wherein a fractal structure parameter alpha<SUB>1 </SUB>at length scales ranging from 50 nm to 150 nm and a fractal structure parameter alpha<SUB>2 </SUB>at length scales ranging from 150 nm to 353 nm satisfy the following formulas (1) and (2): <?in-line-formulae description="In-line Formulae" end="lead"?>-0.0068S+2.548<=alpha<SUB>1</SUB><=-0.0068S+3.748 ( 1 ) <?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>-0.0011S+1.158<=alpha<SUB>2</SUB><=-0.0011S+2.058 ( 2 ) <?in-line-formulae description="In-line Formulae" end="tail"?> wherein S is a BET specific surface area (m<SUP>2</SUP>/g) of the fine silica particles, in the measurement of small-angle X-ray scattering. When used as a filler for a semiconductor-encapsulation resin or when used as a filler for a polishing agent or for a coating layer for ink jet papers, the fine silica particles are available at high content without substantial enhancement of the viscosity. Besides, when used as a filler for the resin, the fine silica particles improve the strength of the molding compound. Furthermore, when used as a toner additive for electrophotography, the fine silica particles improve the free-flow property of the toner without removal from the toner surfaces.
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