Patent ID: 8502937
Filing Date: 2013-08-06
Classification: G02B

Abstract:
1. A protective film for polarizers, comprising a cellulose acetate resin having a degree of acetyl substitution of from 2.1 to 2.5, which satisfies 25<Re<100 and 50<Rth<300 wherein Re means retardation in the plane of the film and Rth means retardation in the thickness direction of the film, and in which the cellulose acetate resin contributes to optical expression of from 40% to 61% of the Re in the film, wherein the protective film further comprises a polyester of an aromatic dicarboxylic acid selected from the group consisting of phthalic acid, terephthalic acid and isophthalic acid, and an aliphatic diol having 2 to 20 carbon atoms, and wherein the cellulose acetate resin has an acetyl group only as an acyl group of the cellulose acetate resin.