RAW FILM FOR RETARDATION FILM, RETARDATION FILM, AND LIQUID-CRYSTAL DISPLAY

摘要

A film comprising a propylene-based random or block copolymer. It is useful as a raw film for obtaining retardation films through stretching. The copolymer constituting the film has crystals comprising smectic crystals, the proportion of the smectic crystals to all crystals in the copolymer being 90% or higher. This film has an in-plane retardation of 50 nm or less and a thickness of 30-200μm. The copolymer is one forming a film which, when stretched at a pulling rate of 100 mm/min at such a temperature as to result in a stress at 200% strain of 0.8±0.1 MPa, gives a stress-strain curve in which the parameter (A) calculated with the equation (1) is in the range of 0.0007-0.1. (A) = (B-B)/400 equation (1).(In the equation, Band Brepresent stresses (MPa) at strains of 600% and 200%, respectively.)