POLYMER FILM, RETARDATION FILM, METHOD FOR PRODUCING RETARDATION FILM AND OPTICAL COMPENSATION POLARIZING PLATE BY USING THE RETARDATION FILM

摘要

PROBLEM TO BE SOLVED: To provide a retardation film having the larger retardation value as the wave length becomes the longer as a single film and also having ≤±4% changing rate of the in-plane directional retardation value (Re) in width direction.;SOLUTION: This polymer film consisting mainly of a cellulose acetate propionate is characterized in that the degree of acetyl substitution (DSac) and the degree of propionyl substitution (DSpr) of the cellulose acetate propionate satisfy formulae: 2.0≤DSac+DSpr3.0, and 1.0≤DSpr3.0, and also the residual amount of a solvent is 0.5 to 5.0 mass%. By stretching the film, it becomes the retardation film having the larger retardation value as the wave length becomes the longer, and also having ≤±4% changing rate of the in-plane directional retardation value (Re) in the width direction.;COPYRIGHT: (C)2007,JPO&INPIT