| 摘要 |
PROBLEM TO BE SOLVED: To obtain a molding material for optical recording medium having low birefringence as well as good moldability by using a copolymerized polycarbonate resin derived from a bisphenol compound having fluorene structure and a specific bisphenol compound. SOLUTION: A polycarbonate to be used as a component of the objective molding material and having an intrinsic viscosity of 0.3-0.5 dL/g can be produced by reacting (A) a compound of formula (R1 to R4 are each H, a 1-5C alkyl, a 6-12C aryl, a 2-5C alkenyl or the like) with (B) 4,4'-[1,3-phenylenebis(1- methylethylidene)]bisphenol, (C) 2,2-bis(4-hydroxyphenyl)propane and (D) a compound capable of forming carbonic acid ester. The component A is preferably 9,9-bis(4-hydroxyphenyl)fluorene and/or 9,9-bis(3-methyl-4-hydroxyphenyl)fluorene. Preferably, the amount of the component A is 15-90 mol% and that of the component B is 5-80 mol% based on the total bisphenol compounds. |
