| 摘要 |
PURPOSE:To obtain the titled copolymer, having a high glass transition temperature as well as low photoelastic constant and used as optical information recording disks, by linking specific components of bis(hydroxyphenyl)-m- diisopropylbenzene, etc. CONSTITUTION:A copolymer which is an aromatic polycarbonate copolymer, obtained by linking 3-40mol.% 1,1-bis-(4-hydroxyphenyl)-m-diisopropylbenzene to 30-80mol.% 2,2-bis-(4-hydroxyphenyl)propane and 5-70mol.% 2,2-bis-(4- hydroxy-3-tert-butylphenyl)propane through carbonate bonds so as to provide 100mol.% total amount of the respective components and having >=125 deg.C glass transition temperature thereof as well as <=60Brewsters (10<-12>m<2>/N) photoelastic constant. Furthermore, the viscosity-average molecular weight is preferably 13,000-50,000. |
