摘要 |
A thermoplastic norbornene resin having a number-average molecular weight (Mn) of 12,000 or more in terms of polyisoprene value measured by gel permeation chromatography and excellent in low birefringence property and resistance to deterioration with greases and oils is obtained by ring-opening polymerizing a polycyclic norbornene monomer containing at least 70% by weight of a norbornene monomer represented by the following formula I (for example, 1,4-methano-1,4,4a,9a-tetrahydrofluorene): <CHEM> (wherein the lower 6-membered ring structure may have a double bond) and hydrogenating the polymer so that the hydrogenation rate of double bond in the main chain is at least 98% and the hydrogenation rate of the 6-membered ring structure is at least 90%. |