COPOLYMER FOR OPTICAL COMPENSATION FILM

摘要

A copolymer for optical compensation film showing a negative orientation birefringence, having excellent transparency, heat resistance, film strength, and optical properties, and is capable of obtaining a beautiful film suitable for an optical compensation film is provided. A copolymer for optical compensation film, containing: 45 to 80 mass% of an aromatic vinyl monomer unit; 5 to 45 mass% of a (meth) acrylic acid ester monomer unit; and 5 to 20 mass% of an unsaturated dicarboxylic acid anhydride monomer unit; wherein the copolymer has an average number molecular weight (Mn) of 5.5 x 10 4 to 9 x 10 4 and a weight average molecular weight (Mw) of 14 x 10 4 to 20 x 10 4 ; and the copolymer has a haze of 1% or less, the haze being measured with a 2 mm thick sample in accordance with ASTM D1003, is provided.