Patent ID: 8901264

Claim:
A copolymer having structural units based on the following monomer (a) and structural units based on the following monomer (b), wherein the content of structural units based on the following monomer (a) is from 5 to 95 mass % in the total structural units, 100 mass %, the content of structural units based on the following monomer (b) is from 5 to 60 mass % in the total structural units, 100 mass %, and the sum of the contents of structural units based on the following monomer (a) and structural units based on the following monomer (b) is at least 70 mass % in the total structural units, 100 mass %: monomer (a): a (meth)acrylate having no polyfluoroalkyl group and having a C 20-30 alkyl group; monomer (b): at least one halogenated olefin selected from the group consisting of vinyl chloride, vinylidene chloride, tetrafluoroethylene and vinylidene fluoride.