Patent ID: 7417104

Claim:
A porous film-forming composition comprising: (A) a polymer obtained by hydrolytic condensation of silicon compounds selected from the group consisting of hydrolyzable silanes having the general formula (1): R 1 n −Si−R 2 4-n (1) wherein R 1 is each independently a monovalent organic group or hydrogen, R 2 is each independently a hydrolyzable group or a hydroxyl group and n is an integer of 0 to 3, a hydrolyzate thereof and a partial condensate thereof, with the proviso that at least one silicon compound having an organic crosslinkable group as R 1 is included, at least one silicon compound is a silane of n=0 in formula (1) and at least one silicon compound is a silane of n=1 in formula (1), wherein R 1 has at least one non-crosslinkable group selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclohexyl, cyclopentyl, octyl, norbornyl, chloromethyl, chloroethyl, 3,3,3-trifluoropropyl, trifluoromethyl, 2-cyanoethyl, nonafluorohexyl, thexyl, piperidinomethyl, morpholinomethyl, morpholinopropyl, 3-(2′3′-dimethoxypropyl)propyl, 3-(2′-methoxypropoxy)propyl, 3-(tetrahydrofurfurylalkoxy)propyl, 5-methylcarboxylate norbornyl, 5-t-butylcarboxylate norbornyl, 5,6-dimethoxycyclohexylethyl, and 3-(2′,3′-dimethoxypropoxy)propyl, the polymer being capable of crosslinking reaction by the organic crosslinkable group, said hydrolytic condensation of a silicon compound being performed in the presence of a hydrolytic catalyst which is a quaternary ammonium hydroxide having the general formula (2): [R 3 4 N] + OH − (2) wherein R 3 is a substituted or unsubstituted monovalent hydrocarbon group of 1 to 4 carbon atoms, (B) an organic solvent, and (C) a crosslinking agent selected from the group consisting of melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, which are substituted with at least one group selected from among methylol, alkoxymethyl, and acyloxymethyl groups, tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triethylolethane triglycidyl ether, and alkenyl ether group-containing compounds.