While not specifically limited, the type of organic solvent in which colloidal silica is dispersed will be, for example, such lower aliphatic alcohols as methanol, ethanol, isopropyl alcohol, n-butanol, isobutanol and the like; such ethylene glycol derivatives as ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate and the like; such diethylene glycol derivativ