Patent ID: 6956070

Claim:
A water-soluble film comprising a modified polyvinyl alcohol which comprises an N-vinylamide monomer unit in an amount of 1 to 10 mole percent, and a carboxyl group and a lactone ring in a total amount of 0.020 to 4.0 mole percent in the molecule, and having a degree of polymerization of 300 to 3000, and a degree of hydrolysis of 75 to 99.5 mole percent wherein said N-vinylamide monomer unit is at least one selected from the group consisting of N-vinyl-2-caprolactam and the monomers represented by formula (I): wherein R 1 denotes a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R 2 denotes a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.