Aqueous organoalkoxysilane/metal oxide sol-gel compositions

Claim 1

A method of making an organoalkoxysilane/metal oxide sol-gel composition in an aqueous medium comprising the steps of: a. adding a less than equivalent quantity of water to an organoalkoxysilane of the general formula R.sub.x Si(OR').sub.4-x wherein R is an organic radical, R' is a low molecular weight alkyl radical, and x is at least one and less than 4; b. partially hydrolyzing said organoalkoxysilane according to the general reaction R.sub.4 Si(OR').sub.4-x +yH.sub.2 O→R.sub.x Si(OR').sub.4-x-y (OH).sub.y +yR'OH wherein y is at least one and less than 4-x, until said quantity of water is essentially completely reacted; c. adding to said essential anhydrous partially hydrolyzed organoalkoxysilane a metal alkoxide of the general formula M(OR") z wherein M is a metal selected from the group consisting of titanium and zirconium, R" is a low molecular weight alkyl radical, and z is the valence of M; d. reacting said metal alkoxide with said partially hydrolyzed organoalkoxysilane according to the following general reaction ##STR5## until substantially all of said metal alkoxide has reacted with said partially hydrolyzed organoalkoxysilane to form an oxide network; and e. adding sufficient water to essentially completely hydrolyze said composition to form an aqueous sol.

Claim 2

A method of making an organoalkoxysilane/metal oxide sol-gel composition in an aqueous medium comprising the steps of: a. adding a less than equivalent quantity of water to an organoalkoxysilane of the general formula R.sub.x Si(OR').sub.4-x wherein R is an organic radical, R' is a low molecular weight alkyl radical, and x is at least one and less than 4; b. partially hydrolyzing said organoalkoxysilane according to the general reaction R.sub.4 Si(OR').sub.4-x +yH.sub.2 O→R.sub.x Si(OR').sub.4-x-y (OH).sub.y +yR'OH wherein y is at least one and less than 4-x, until said quantity of water is essentially completely reacted; c. adding to said essential anhydrous partially hydrolyzed organoalkoxysilane a metal alkoxide of the general formula M(OR") z wherein M is a metal selected from the group consisting of titanium and zirconium, R" is a low molecular weight alkyl radical, and z is the valence of M; d. reacting said metal alkoxide with said partially hydrolyzed organoalkoxysilane according to the following general reaction ##STR5## until substantially all of said metal alkoxide has reacted with said partially hydrolyzed organoalkoxysilane to form an oxide network; and e. adding sufficient water to essentially completely hydrolyze said composition to form an aqueous sol.