| 摘要 |
PROBLEM TO BE SOLVED: To obtain a copolymer polycarbonate having excellent impact resistance, color tone and heat resistance, having good balance between refractive index, and also dispersion characteristics, and also having a low photoelectric constant by making the copolymer polycarbonate include specific two kinds of constitutive unit. SOLUTION: This polycarbonate is obtained by including, as constitutive units, unit of formula I [X is a group of formula II (R3 is a 3-10C alkylene), O, S or the like; R1 and R2 are each H, a 1-10C alkyl or halogen; (m) and (n) are each the number of substituents, being 0-4] and unit of formula III pref. in the molar ratio of (90:10) to (10:90). Specifically, this polycarbonate is obtained by subjecting (A) an aromatic dihydroxy compound of formula IV [e.g. 1,1-bis(hydroxyphenyl)cyclohexane], (B) a tricyclo(5.2.1.02.6) decanedimethanol and (C) a carbonic diester having a chlorine content of <=20 ppm (e.g. diphenyl carbonate) to polycondensation in a molten state under heating.
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