Patent ID: 8552102

Claim:
An aqueous coating solution, comprising a copolymer consisting of a partially hydrolyzed polyvinyl alcohol having an average polymerization degree of 300 to 500 and a polymerizable vinyl monomer in a weight ratio of 6:4 to 9:1, wherein: the polymerizable vinyl monomer consists of acrylic acid and methyl methacrylate combined in a weight ratio of 3:7 to 0.5:9.5 in the copolymer, the weight ratio of the partially hydrolyzed polyvinyl alcohol having an average polymerization degree of 300 to 500, the methyl methacrylate and the acrylic acid is 60 to 90: 7 to 38: 0.5 to 12, and the partially hydrolyzed polyvinyl alcohol excludes a thiol modified polyvinyl alcohol the aqueous coating solution excludes any other polyvinyl alcohol.