| 摘要 |
PURPOSE:To obtain a polycarbonate polymer having excellent optical properties and being useful as, e.g., a material for optical instruments, by reacting a specified bisphenol with a carbonic ester-forming compound. CONSTITUTION:A bisphenol of formula I is reacted with a carbonic ester- forming compound to obtain a polycarbonate polymer comprising repeating units of formula II and having a reduced viscosity >=0.2dl/g (as measured in a 0.5g/dl concentration solution in methylene chloride at 20 deg.C). In the formulae, X is a single bond, an ether bond, a thioether bond, -SO2-, a group of formula III (wherein R<1> and R<2> are each H, a 1-5C alkyl or phenyl), a group of formula IV (wherein n is 2-20) or a group of formula V (wherein n' is 4-8). This polymer has a particularly high refractive index and, for example, a polycarbonate obtained from 2,2-bis(3-phenyl-4-hydroxyphenyl)propane has a refractive index of 1.6662 at 20 deg.C.
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