| abstract |
An object of the present invention is to provide a retardation film made of a norbornene-based copolymer having excellent heat resistance, low specific gravity, low birefringence, low photoelasticity, low wavelength dispersion, and high retardation compensation. This invention is a monomer represented by general formula (I), the monomer represented by general formula (II), the monomer represented by general formula (III), the monomer represented by general formula (IV), and general formula (V). Norbor containing 40-60 mol% of repeating units derived from at least 1 sort (s) of norbornene-type monomer chosen from the group which consists of monomers shown, and 60-40 mol% of repeating units derived from an acyclic olefinic monomer. A retardation film composed of a norbornene-based copolymer composition containing a nene-based copolymer, wherein the norbornene-based copolymer composition is stretched twice while heating to a glass transition temperature determined by dynamic viscoelasticity after molding into a film form A film is retardation film characterized by the in-plane birefringence value (DELTA) n defined by the following formula being 0.0033 or more.n n n Δn = nx-nyn n n n Retardation film |