Patent ID: 8202502

Claim:
A method of preparing hydrophobic silica particles comprising: (a) providing a stable acidic aqueous colloidal dispersion of silica particles, wherein the content of free alkali metal cation in the aqueous dispersion is 0.05 wt. % or less, (b) combining the dispersion with an alkoxysilane compound to provide a reaction mixture in aqueous dispersion form, wherein the reaction mixture comprises no more than 40 wt. % of organic solvent, and (c) drying the reaction mixture of step (b) to provide hydrophobic silica particles having a ratio T2:T3 of about 0.4 or more, wherein T2 is the intensity of a peak having a chemical shift in the CP/MAS 29 Si NMR spectrum centered within the range of −56 ppm to −59 ppm, and wherein T3 is the intensity of a peak having a chemical shift in the CP/MAS 29 Si NMR spectrum centered within the range of −65 ppm to −69 ppm.