OPTICAL FILM

摘要

PURPOSE: An optical film is provided to control optical anisotropy of a cellulose resin by controlling kind and degree of a substituent, thereby capable of controlling retardation without addition of a retardation controller. CONSTITUTION: An optical film comprises a cellulose ester resin in which a part of hydroxy groups in cellulose are substituted by hydrogen as a base resin. The substituent is one or more kinds in an acryl group of chemical formula 1: -CO-R1, and chemical formula 2:-X-R2. The substitution degree of the acyl group is 2-2.9. The total degree of substitution is 0.01-1.0 of the substituent except the acryl group. The weight average molecular weight of the cellulose ester resin is 150,000-400,000. The optical film additionally comprises 5-50 parts by weight of cellulose triacetate resin, and 100.0 parts by weight of cellulose ester resin.