| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyurethane having excellent heat resistance allowing various kinds of functional layers to be formed at high temperature, and also having both of excellent optical characteristics and mechanical characteristics enabling a film to be formed; and to provide an optical film comprising the polyurethane. SOLUTION: The polyurethane has a repeating unit represented by general formula (1) (wherein, ringβand ringγare each a monocyclic or polycyclic ring; two ringsγare the same or different, and each linked to one quaternary carbon on the ringβ; L is a divalent linking group; and R<SP>1</SP>and R<SP>2</SP>are each a substituent and may form a ring by bonding to each other). COPYRIGHT: (C)2006,JPO&NCIPI
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