Patent ID: 8632888

Claim:
A coating solution consisting of: a first solvent selected from the group consisting of water, methyl alcohol, ethyl alcohol, isopropyl alcohol and mixtures thereof; 0. 1 to 30 parts by weight of a polycarboxylic acid-based polymer relative to 100 parts by weight of the solvent, wherein the polycarboxylic acid-based polymer is a (co)polymer of α,β-monoethylenically unsaturated carboxylic acids; 0.01 to 0.35 chemical equivalent of a hydroxide of an alkali metal relative to an amount of carboxyl group in the polycarboxylic acid-based polymer; a multivalent metal compound selected from the group consisting of calcium hydroxide of 0.05 to 0.75 chemical equivalent relative to the amount of the carboxyl group and zinc oxide of 0.05 to 0.50 chemical equivalent relative to the amount of the carboxyl group; an optional additional polymer; and an optional inorganic layered compound, wherein a number average molecular weight of the polycarboxylic acid-based polymer is in a range of 40,000 to 10,000,000.