| abstract |
Disclosed is a copolymer which is capable of providing an article surface with sufficient dynamic water repellency, water repellency after air-drying and friction durability, while having little burden on the environment. Also disclosed are a method for producing the copolymer, a water repellent composition, and an article having excellent dynamic water repellency, water repellency after air-drying and friction durability. The copolymer has a structural unit derived from the monomer (a) described below and a structural unit derived from the monomer (b) described below, with the ratio of the structural unit derived from the monomer (a) being 5-95% by mass and the ratio of the structural unit derived from the monomer (b) being 5-60% by mass relative to the total structural units (100% by mass). In the copolymer, the total ratio of the structural unit derived from the monomer (a) and the structural unit derived from the monomer (b) is not less than 65% by mass. Monomer (a): a (meth)acrylate not containing a polyfluoroalkyl group but having an alkyl group with 20-30 carbon atoms Monomer (b): a halogenated olefin |