Patent ID: 6090439
Filing Date: 2000-07-18
Classification: C01B,C01P,C09C

Abstract:
A method of preparing treated silica comprising:(a) providing a mixture comprising:(i) at least one silica precursor selected from the group consisting of compounds of the formula R.sub.n SiX.sub.4-n, wherein each R is independently selected from the group consisting of aliphatic hydrocarbon and fluorocarbon radicals of 6 carbon atoms or less and phenyl radicals, each X is independently selected from the group consisting of halogen radicals, and n is an integer from 0 to 2, inclusive,(ii) water,(iii) an acid, and(iv) at least one hydrophobing agent selected from the group consisting of compounds of the formula R.sub.3 SiX, cyclic siloxanes of the general formula (R.sub.2 SiO).sub.y, and linear siloxanes of the general formula R'.sub.3 Si--O--{Si(R).sub.2 --O}.sub.z --SiR'.sub.3, wherein each R' is independently selected from the group consisting of aliphatic hydrocarbon and fluorocarbon radicals of 6 carbon atoms or less, phenyl radicals, and hydroxyl radicals, each R is independently selected from the group consisting of aliphatic hydrocarbon and fluorocarbon radicals of 6 carbon atoms or less and phenyl radicals, each X is independently selected from the group consisting of halogen radicals, and hydroxyl radicals and salts thereof, y is 3 or 4, and z is an integer from 0 to 10, inclusive, wherein substantially the only silica present in said mixture is that generated in situ, and(b) allowing said treated silica to form in said mixture, and(c) recovering said treated silica from said mixture.