PROCESS FOR THE PREPARATION OF A SOL OF DISPERSED SILICA IN A LOWER ALKANOL AND APPLICATION OF SAID ORGANOSOL, PARTICULARLY FOR THE PREPARATION OF COATING COMPOSITIONS FOR GLASS SURFACES

摘要

Process for obtaining a silica sol dispersed in a C1-C3 alkanol containing by weight less than 1% of water and up to 50% of silica in the form of discrete particles with an average diameter of between 5 and 100 nm, not linked to each other by siloxane bonds, in which an aqueous silica sol containing up to 50% silica is mixed at room temperature in the form of discrete particles with an average diameter of between 5 and 100 nm , not linked to each other by siloxane bonds, with at least a portion by weight relative to the aqueous silica sol of the corresponding C1-C3 alkanal, and then this mixture is subjected to pervaporation at a lower temperature or equal to 80 .degree.C until a dispersion containing by weight less than 1% of water is obtained, silica sol thus obtained and use for obtaining compositions intended for coating organic glasses.