Patent ID: 7968019
Filing Date: 2011-06-28
Classification: C09K,G02B

Abstract:
1. A method for producing an optical compensation film comprising the steps of: melting a composition containing a cellulose resin having a residual sulfuric acid content of 0.1-50 ppm, a hindered phenol compound in an amount of 0.01-5% by weight and at least one kind of non-phosphate type plasticizers of a polyol ester plasticizer, a polyester plasticizer, a citrate plasticizer, and a phthalate ester plasticizer and containing a phosphate type plasticizer with a content less than 1.0% by weight so as to obtain a melt by heating the composition to a melting temperature A of 200° C. or more and 280° C. or less; casting the melt on a support to form a cellulose resin film; providing a polymer layer on the cellulose resin film; and stretching the cellulose resin film together with the polymer layer under a stretching temperature B, wherein the cellulose resin is a mixed fatty acid ester of cellulose having a total acyl group substitution degree of 2.0 to 2.9, and the hindered phenol compound is a compound represented by the following Formula (20), in the above formula, R1, R2 and R3 each is a substituted or unsubstituted alkyl group, and at least one of R1 and R2 is a t-butyl group, wherein the melting temperature A and the stretching temperature B satisfy the following conditional formula: