SILICA POWDER, PROCESS FOR ITS PRODUCTION, AND COMPOSITION EMPLOYING IT

摘要

A SILICA POWDER CONTAINING AN ULTRAFINE POWDER IN AN AMOUNT OF FROM 0.1 TO 20 MASS % AND HAVING AN AVERAGE SPHERICITY OF AT LEAST 0.85, WHEREIN THE ULTRAFINE POWDER HAS, AS THE PARTICLE SIZE MEASURED BY A DYNAMIC LIGHT SCATTERING PARTICLE SIZE DISTRIBUTION MEASURING APPARATUS, AN AVERAGE PARTICLE SIZE OF FROM 150 TO 250 NM, LESS THAN 10 MASS % OF THE ULTRAFINE POWDER HAVING A PARTICLE SIZE OF AT MOST 100 NM BEING LESS THAN 10 MASS % (NOT INCLUDING 0 MASS %) AND FROM 10 TO 50 MASS % OF THE ULTRAFINE POWDER HAVING A PARTICLE SIZE EXCEEDING 100 NM AND NOT EXCEEDING 150 NM. NO