| 摘要 |
PROBLEM TO BE SOLVED: To provide hydrophobized dry silica microparticles which exhibit a thickening effect to a hydrophobic resin while having a primary particle diameter of 50 to 150 nm, compared to existing dry silica microparticles having a primary particle size similar to the above size, and which have excellent dispersibility and are suitably used as a filler for a resin and an external additive for a toner.SOLUTION: Hydrophobized dry silica microparticles have a trimethylsilyl group on a surface thereof and have (1) a BET specific surface area of 15 to 50 m/g; (2) a DBP oil absorption amount of 32 to 45 g per 100 g of the hydrophobized dry silica microparticles; (3) a D/Dof 1.00 or more and less than 1.60; (4) a carbon content of 0.24 wt.% or more; and (5) a hydrophobicity degree of 65 vol.% or more by a methanol titration method. |
