Patent ID: 6872765

Claim:
A sol-gel coating material comprising (A) an acrylate copolymer solution comprising a reaction product of: a1) at least one (meth)acrylic ester that is substantially free of acid groups, a2) at least one ethylenically unsaturated monomer that carries at least one hydroxyl group per molecule and is substantially free of acid groups, and a3) at least one ethylenically unsaturated monomer that carries per molecule at least one acid group that can be converted into a corresponding acid anion group; (B) a stock varnish comprising a hydrolysis and condensation product of at least one hydrolyzable silane of the general formula I SiR 4 (I), in which the variable R has the following definition: R=hydrolyzable groups, hydroxy groups, and nonhydrolyzable groups, with the proviso that at least one hydrolyzable group is present; and (C) an additive solution comprising c1) at least one ethylenically unsaturated compound containing at least one epoxide group, c2) at least one silane having at least one nonhydrolyzable group R that contains at least one epoxide group, and c3) at least one adduct of the at least one silane having at least one nonhydrolyzable group R that contains at least one amino group and at least one cyclic ethylenically unsaturated dicarboxylic anhydride.