Thermoplastic norbornene resin based optical film

An optical film comprising at least one resin-layer comprising a thermoplastic norbomene resin formed of a polymer comprising:

• a structural unit a represented by a general formula (1) shown below,
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• wherein,
• n represents either one of 0 and 1,
• m represents either one of 0, and an integer of at least 1;
• X represents either one of a group represented by a formula —CH═CH— and a group represented by a formula —CH2CH2—;
• R1, R2, R3, and R4 each represent, independently, any one of a hydrogen atom, a halogen atom, a substituted or unsubstituted hydrocarbon group of 1 to 30, carbon atoms which may contain a linkage group incorporating an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom, and a polar group;
• or R1 and R2, or R3 and R4, or R2 and R3 may be bonded to each other to form a hydrocarbon ring or a heterocyclic ring (wherein said hydrocarbon ring or said heterocyclic ring may be either one of a separate stand-alone structure, or a polycyclic structure formed through condensation with another ring, and said formed hydrocarbon ring or said heterocyclic ring may be an aromatic ring or a non-aromatic ring),
• wherein within at least a portion of said structural units a incorporated within said polymer, either at least one of said groups R1 to R4 has a group represented by a general formula (2) shown below, or said groups R2 and R3 are bonded to each other to form at least one group selected from general formulas (3) and (4) shown below:
• —(CH2)p—O—C(O)—R5 (2)
• [wherein, p represents an integer of 1 to 5, and R5 represents any one of a biphenylyl group, a naphthyl group (α or β), an anthracenyl group, and one of these groups in which a hydrogen atom has been substituted with a halogen atom or a hydrocarbon group of 1 to 10 carbon atoms],
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• [wherein, R1 and R4 represent identical meanings as defined above in relation to said general formula (1), and R6 to R11 each represent, independently, any one of a hydrogen atom;
• a halogen atom;
• a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms which may contain a linkage group incorporating an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom;
• and a monovalent polar group], and
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• [wherein, R1 and R4 represent identical meanings as defined above, and R12 to R15 each represent, independently, any one of a hydrogen atom;
• a halogen atom;
• a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms which may contain a linkage group incorporating an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom;
• and a monovalent polar group, V and W each represent, independently, either one of a single bond, and a bivalent group selected from a group consisting of —O—, —CO—, —NR16—, —(CR17R18)q— (wherein q=1 to 5), —COO— and —OCO—, and R16 to R18 each represent, independently, any one of a hydrogen atom, a halogen atom, and an aliphatic hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group of 1 to 10 carbon atoms],
• a plurality of X's present in a molecule of said copolymer being the same or different.