| 摘要 |
PURPOSE: To obtain a copolymer improved in birefringency and moldability without detriment to the excellent transparency and mechanical properties inherent in the constituent aromatic polycarbonate by using specified two or three dihydric phenols. CONSTITUTION: This copolymer is an aromatic polycarbonate (A) comprising repeating units of formula I and repeating units of formula II and having a I/II molar ratio of 80:20 to 1:99 or an aromatic polycarbonate copolymer (B) comprising repeating units I, repeating units II and repeating units III and having a molar ratio (I)/(II+III) of 80:20 to 1:99 and a content of II of 50mol% or above based on the total of II and III. The two dihydric phenols used in the production of copolymer A are 4,4'-(m-phenylenediisopropylidene) diphenol and 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, and to produce copolymer B, 9,9-bis(4-hydroxyphenyl) fluorene is further used. |
