Patent ID: 6352679
Filing Date: 2002-03-05
Classification: B82Y,C01B,C01P,C09C

Abstract:
An ultrafine particle silicon dioxide comprising:silicon dioxide powders in the range of ultrafine particles having a BET specific surface area in the range of 350 m2/g to 600 m2/g, a CTAB specific surface area greater than 400 m2/g, a ratio of BET/CTAB specific surface areas in the range of 0.6 to 1.1, a number average of primary particle diameters in the range of 1 to 20 nm, a void volume measured with a mercury porosimeter in the range of 0.1 to 1.0 ml/g, and a linseed oil absorption in the range of 350 to 600 ml/100 g, wherein the ultrafine particle silicon dioxide is prepared by the steps of: mixing a volatile silicon compound with a mixed gas including an inflammable gas and oxygen to be a mixture; and decomposing said volatile silicon compound at temperatures between approximately 1000Â° C. to 2100Â° C. under a flame generated by burning said mixture, wherein mole equivalents of oxygen and hydrogen in said mixed gas are controlled to be 2.5 to 3.5 and 1.5 to 3.5 respectively against 1 mole equivalent of said volatile silicon compound wherein the ultrafine particle silicon dioxide comprises silicon dioxide powders in the range of ultrafine particles having a BET specific surface area of 350 m2/g to 600 m2/g, has a CTAB specific surface area of greater than 400 m2/g, and has a ratio of BET/CTAB specific surface areas of 0.6 to 1.1, a number average of primary particle diameters of 1 to 20 nm, void volume measured with a mercury porosimeter of 0.1 to 1.0 ml/g and linseed oil absorption of 350 to 600 ml/100 g.