POLYCARBONATE COPOLYMER AND OPTICAL DISK

摘要

An aromatic polycarbonate copolymer is useful for a substrate of an optical disk and is composed of 1 to 99 mole percent of the unit of 2,2-bis(4-hydroxy-3-tertiary-butyl-phenyl)propane, 99 to 1 mole percent of the unit of a comonomer selected from the group consisting of (1) 2,2-bis(4-hydroxyphenyl)propane, (2) 4,4'-dihydroxy-2,2,2-triphenylethane, (3) 2,2-bis(4-hydroxy-3-methylphenyl)-propane, (4) 1,1'-bis(4-hydroxyphenyl)-p-diisopropylbenzene, (5) 1,1'-bis(4-hydroxyphenyl)-m-diisopropyl-benzene, (6) 2,2-bis(4-hydroxyphenyl)butane, (7) 2,2-bis(4-hydroxyphenyl)-4-methylpentane, (8) 2,2-bis(4-hydroxyphenyl)octane, (9) 1,1-bis(4-hydroxyphenyl)cyclohexane and (10) 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane and a carbonate group located between the two units.