Surface-treated magnetic iron oxide particles and the surface-treated black paint using magnetic iron oxide particles, a rubber-resin composition

摘要

PROBLEM TO BE SOLVED: To provide a surface-treated magnetic iron oxide particle powder having a small agglomerated particle and good dispersibility in toluene and suitable for a black coating material and a rubber-resin composition.;SOLUTION: The surface-treated magnetic iron oxide particle powder whose surface is coated with a specific silane coupling agent of 4-16 μmol/m² and having 0.05-0.70 μm average particle diameter, 0.25-1.80 μm dispersed particle diameter d50 in toluene and 0.65-3.50 μm dispersed particle diameter d90 in the toluene is obtained by subjecting the magnetic iron oxide particle becoming a nucleus to a hydrophobic treatment in an aqueous medium, then subjecting to a fluidized bed drying and heat treating, or subjecting the particle to the hydrophobic treatment with a wheel type kneading machine or a grinder, then simultaneously performing a heat treating and grinding with a dryer having an oscillating mechanism wherein a medium such as a ball is charged.;COPYRIGHT: (C)2010,JPO&INPIT