| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a retardation film which shows a negative intrinsic birefringence value and ensures large wavelength dispersion of in-plane retardation, and a copolymer from which such a retardation film is obtained. <P>SOLUTION: The copolymer includes a specific acrylate-based repeating unit, a specific vinyl-based repeating unit and a specific acrylonitrile-based repeating unit, wherein the content ratio of the acrylate-based repeating unit is 1-30 mol% relative to the total amount of repeating units constituting the copolymer, the content ratio of the acrylonitrile-based repeating unit is 10-35 mol% relative to the total amount of the repeating units constituting the copolymer, and the total content ratio of the acrylate-based repeating unit, the vinyl-based repeating unit and the acrylonitrile-based repeating unit is ≥70 mol% relative to the total amount of the repeating units constituting the copolymer. <P>COPYRIGHT: (C)2009,JPO&INPIT |
