| abstract |
A resin composition having excellent heat resistance and dynamic characteristic and having excellent characteristics as a composition for optical films exhibiting negative birefringence, an optical film exhibiting negative birefringence comprising the resin composition, and a process of producing the optical film are provided. The resin composition comprises (a) 30-95% by weight of a copolymer containing an α-olefin residual group unit and an N-phenyl-substituted maleimide residual group unit and having a weight average molecular weight, as reduced into standard polystyrene, of 5×10 3 to 5×10 6 ; and (b) 70-5% by weight of an acrylonitrile-styrene based copolymer, a weight ratio of an acrylonitrile residual group unit to a styrene residual group unit being 20/80 to 35/65, and having a weight average molecular weight, as reduced into standard polystyrene, of 5×10 3 to 5×10 6 . |