摘要 |
The product has a polymeric organic film chemically bonded to the silica wherein the bonding is effected by means of a chlorosilyl group formed by reacting SiCl4 with hydroxyl groups of the silica, the polymeric organic film being constituted by a polyol having an average molecular weight of from 3,000 to 100,000, and the surface of said product being substantially free of chlorosilyl groups. The preferred polyols are polyethylene glycol, polypropylene glycol and polyesters of alkylene diols of 2 to 16 carbon atoms and dicarboxylic acids of 3 to 10 carbon atoms. |