| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydrophobized silica composition in which a silica fine powder acts effectively as a spacer to a resin powder and that has a high effect to impart the fluidity for a long term without being embedded within the resin when the hydrophobized silica composition is added to the resin powder. SOLUTION: The hydrophobized silica composition is comprised of a hydrophobized mixture of the silica fine powder (A) of which the average particle size is 0.05-1μm and a fumed silica (B), wherein the ratio R% of the fumed silica (B) occupied in the mixture is in a range of following formula (1) and is characterized in that the content of aggregated particles of 710μm or more is 200 ppm or less and especially it is useful as an external additive for toners, provided that 3/(d+0.03)≤R≤40/(d+0.4); (1), wherein d is the average particle size (unit:μm) of the silica fine powder (A). COPYRIGHT: (C)2005,JPO&NCIPI |
