| 摘要 |
PURPOSE: A polycarbonate copolymer is provided to reduce yellowing generated in molding at a high temperature by restricting the tin content within a copolymer to be less than 0.5 ppm, and to reduce discoloration in a durability test. CONSTITUTION: A polycarbonate copolymer has a repeating unit represented by the following chemical formula I and II. The tin content (as an element) is 0.5 ppm or less. In the chemical formula I and II, R^1 and R^2 are independently C1-6 alkyl group; X is a single bond and represents any one selected from C1-8 alkylene group, C2-8 alkylidene group, C5-15 cycloalkylene group, C5-15 cycloalkylidene group, -S-, -SO-, -SO2-, -O-, -CO- or a bond represented by the following chemical formula III-1 or III-2; R^3 and R^4 are independently C1-3 alkyl group; Y is C2-15 linear or branched alkylene group; a-d are an integer of 0-4; and n is an integer of 2-200.
|
