Patent ID: 7582339

Claim:
A biaxial-optical polynorbornene-based film composed of an addition-type polynorbornene-based polymer, wherein, when nx is a refractive index in a slow axis direction (x-direction) in-plane of film, ny is a refractive index in a y-direction which is perpendicular to the x-direction in-plane of film, and Nz=(nx−nz)/(nx−ny), the film satisfies the two requirements of nx>ny>nz and 1<Nz≦10, wherein the polynorbornene-based polymer is a copolymer obtained by addition-polymerizing two or more norbornene-based monomers composed of a monomer represented by formula (1) wherein m is an integer of 0-4; and each of R 1 , R 2 , R 3 , and R 4 can be the same or different and is a hydrogen atom, a halogen atom, a linear or branched alkyl, alkenyl, or vinyl having 1-20 carbon atoms, a hydrocarbon-substituted or unsubstituted cycloalkyl having 5-12 carbon atoms, a hydrocarbon-substituted or unsubstituted aryl having 6-40 carbon atoms, a hydrocarbon-substituted or unsubstituted aralkyl having 7-15 carbon atoms, an alkynyl having 3-20 carbon atoms, a linear or branched haloalkyl, haloalkenyl, or halovinyl having 1-20 carbon atoms, a hydrocarbon-substituted or unsubstituted halocycloalkyl having 5-12 carbon atoms, a hydrocarbon-substituted or unsubstituted haloaryl having 6-40 carbon atoms, a hydrocarbon-substituted or unsubstituted haloaralkyl having 7-15 carbon atoms, a haloalkynyl having 3-20 carbon atoms, or a polar group consisting of —C(═O)OR 6 , —R 5 C(═O)OR 6 , —OR 6 , —R 5 OR 6 , —OC(O)OR 6 , —R 5 OC(═O)OR 6 , —C(═O)R 6 , —R 5 C(O)R 6 , —OC(═O)R 6 , —R 5 OC(═O)R 6 , —(R 5 O)p-OR 6 , —(OR 5 )p-OR 6 , —C(═O)—O—C(O)R 6 and —R 5 C(═O)—O—C(═O)R 6 , wherein R 5 is a linear or branched alkyl, haloalkyl, alkenyl, haloalkenyl, or halovinyl having 1-20 carbon atoms, a hydrocarbon-substituted or unsubstituted cycloalkyl or halocycloalkyl having 4-12 carbon atoms, a hydrocarbon-substituted or unsubstituted aryl or haloaryl having 6-40 carbon atoms, a hydrocarbon-substituted or unsubstituted aralkyl or haloaralkyl having 7-15 carbon atoms, or an alkynyl or haloalkynyl having 3-20 carbon atoms; R 6 is a hydrogen atom, a halogen atom, a linear or branched alkyl, haloalkyl, alkenyl, haloalkenyl, halovinyl, alkoxy, haloalkoxy, carbonyloxy, or halocarbonyloxy having 1-20 carbon atoms, a hydrocarbon-substituted or unsubstituted cycloalkyl or halocycloalkyl having 4-12 carbon atoms, a hydrocarbon-substituted or unsubstituted aryl, haloaryl, aryloxy, or haloaryloxy having 6-40 carbon atoms, a hydrocarbon-substituted or unsubstituted aralkyl or haloaralkyl having 7-15 carbon atoms, or an alkynyl or haloalkynyl having 3-20 carbon atoms; and p is an integer of 1-10; provided at least one of R 1 , R 2 , R 3 and R 4 is a polar group consisting of —C(═O)OR 6 , —R 5 C(═O)OR 6 , —OR 6 , —R 5 OR 6 , —OC(O)OR 6 , —R 5 OC(═O)OR 6 , —C(═O)R 6 , —R 5 C(O)R 6 , —OC(═O)R 6 , —R 5 OC(═O)R 6 , —(R 5 O)p-OR 6 , —(OR 5 )p-OR 6 , —C(═O)—O—C(O)R 6 and —R 5 C(═O)—O—C(═O)R 6 .