A polarizing plate protective film, a method of manufacturing the same, a polarizing plate and a liquid crystal display device

An object of the present invention, high water resistance, a heat resistance and toughness, the occurrence of display unevenness of the liquid crystal display device (Bendomura) inhibit, and can suppress the thermal shrinkage variation after coating the functional layer a polarizing plate protective film, a method of manufacturing the same, is to provide a polarizing plate and a liquid crystal display device. Protective film for polarizing plate of the present invention, as a main component of the thermoplastic resin, a copolymer obtained by polymerizing an aromatic vinyl monomer and an unsaturated nitrile monomer (A) and the copolymer having a lactone ring structure (B ) and a mass ratio a: B = 95: 5~50: characterized in that it contains in the range of 50.