Thermoplastic resin film, process for production thereof and optical film

摘要

A thermoplastic resin film includes at least a thermoplastic resin A having a glass transition temperature of equal to or higher than 150 DEG C, an enthalpy relaxation temperature from 140 DEG C to 200 DEG C and an enthalpy relaxation magnitude from 0.01 to 2.0 kJ/mol. The film has a thickness equal to or more than 30 mu m, a retardation less than or equal to 20 nm. Such a film can be used as a substrate of a liquid crystal display device.