ULTRAFINE COMPOSITE SILICA POWDER AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide ultrafine composite silica powder having moderate electrical conductivity and excellent reinforcing effect for resins and rubbers and provide a method for easily producing the ultrafine composite silica powder having excellent reinforcing effect in high productivity. SOLUTION: The ultrafine composite silica powder has a silica layer formed on carbon powder and/or silicon carbide powder and has a silanol group number of 3-10/nm2 on the surface of the powder and a specific surface area of 30-300 m2/g. The ultrafine powder is produced by forming an SiO layer on the surface of carbon powder and/or silicon carbide powder and heat-treating in steam atmosphere at 600-900 deg.C to convert the SiO layer into a silica layer and apply silanol groups to the powder.