Process of producing hydrophobic organosilica sol

摘要: A process of producing a hydrophobic organosilica sol which comprises aging reaction mixture at 0 to 100° C. in the state that an alkali present is removed or neutralized with acid equivalent amount more, thereby forming silylation-treated silica having colloidal dispersed therein, comprising: (a) hydrophilic specific surface area 5.5 550 m2 /g SiO2 concentration 5 55% by weight, (b) silylating agent disiloxane compound and/or monoalkoxysilane millimolar ratio 0.03 2 terms Si atom per 100 silica, and (c) medium, as residue thereof, comprising mixed solvent organic solubility water 0.1 12% weight alcohol 1 3 carbon atoms 0.05 20 solvent, 15% less based on medium.