Bisphenol-A polycarbonate prepn. - by melt transesterification of molten bisphenol and diphenyl carbonate

摘要

An aromatic polycarbonate of high mol.wt. is prepd. from diphenyl carbonate and Bisphenol A according to the known melt transesterification process, but using raw matls., which as pure substances have never passed through the solid phase, in proportions by wt. of between 30:70 and 70:30 (pref. 45:55 and 55:45). Previous process using crystalline diphenyl carbonate and Bisphenol A led to difficulties in excluding O2 and consequently poor coloured prodt. Use of molten, never crystallised raw matls. makes O2 exclusion much easier giving prodt. of pale colour.