Method for production of polyster resin film, and polyester resin film, antireflective film and diffusion film produced by the method

Abstract

One aspect of the present invention provides a method for production of a polyester resin film comprising melt extruding a polyester resin into a sheet shape, cooling and solidifying the polyester resin sheet on a casting drum, then longitudinally stretching the polyester resin sheet in a longitudinal direction, and then passing the longitudinally stretched polyester resin film through a transverse stretching apparatus to transversely stretch the longitudinally stretched polyester resin film in a transverse direction, wherein Xc, Tc, Ts and Te satisfy the formulas of: Tc≦(Ts+Te)/2+2.66Xc≦Tc+60  (1) and 2≦Xc≦30  (2), in which Xc (%) indicates a crystallinity of the film after the longitudinal stretching, Tc (° C.) indicates a crystallization temperature of the film after the longitudinal stretching, Ts (° C.) indicates a film surface temperature at an entrance of a stretching zone of the transverse stretching apparatus, and Te (° C.) indicates a film surface temperature at an exit of the stretching zone of the transverse stretching apparatus.

Dependencies are inferred from the claim text.