Siloxane-tin coatings

Claim 1

A method for preparing a precursor having the formula: ##STR20## where m is from about 1 to about 10, where each X is independently selected from the group consisting of alkyl and alkoxyalkyl radicals containing less than about 6 carbon atoms and Y, where each Y in the precursor is independently a trisubstituted tin radical having the formula: ##STR21## where R 1 , R 2 , and R 3 are independently selected from the group consisting of alkyl, cycloalkyl, and aryl radicals, where R 1 , R 2 , and R 3 contain in combination up to 18 carbon atoms, and where the X's are selected so the ratio of tin atoms to silicon atoms in the precursor is from about 1:50 to (2m+2):m; the method comprising the steps of combining a silicate having the formula: ##STR22## where R 4 represents the group consisting of alkyl and alkoxyalkyl radicals containing less than about 6 carbon atoms, with about n/2 moles of water per mole of the silicate and about n/2 moles of bis-trisubstituted tin oxide having the formula Y-O-Y per mole of the silicate, where the ratio of n to m equals the ratio of tin atoms to silicon atoms in the precursor; and maintaining the temperature at which the silicate, tin oxide, and water are combined below the temperature at which the precursor decomposes.

Claim 2

A method for preparing a precursor having the formula: ##STR20## where m is from about 1 to about 10, where each X is independently selected from the group consisting of alkyl and alkoxyalkyl radicals containing less than about 6 carbon atoms and Y, where each Y in the precursor is independently a trisubstituted tin radical having the formula: ##STR21## where R 1 , R 2 , and R 3 are independently selected from the group consisting of alkyl, cycloalkyl, and aryl radicals, where R 1 , R 2 , and R 3 contain in combination up to 18 carbon atoms, and where the X's are selected so the ratio of tin atoms to silicon atoms in the precursor is from about 1:50 to (2m+2):m; the method comprising the steps of combining a silicate having the formula: ##STR22## where R 4 represents the group consisting of alkyl and alkoxyalkyl radicals containing less than about 6 carbon atoms, with about n/2 moles of water per mole of the silicate and about n/2 moles of bis-trisubstituted tin oxide having the formula Y-O-Y per mole of the silicate, where the ratio of n to m equals the ratio of tin atoms to silicon atoms in the precursor; and maintaining the temperature at which the silicate, tin oxide, and water are combined below the temperature at which the precursor decomposes.