PRODUCTION OF CRYSTALLINE POLYCARBONATE POWDER AND PRODUCTION OF HIGH-MOLECULAR-WEIGHT POLYCARBONATE

摘要

PURPOSE: To obtain a powder which can give a high-quality polycarbonate within a short time by polycondensing 2,2-bis-(4-hydroxyphenyl)propane with diphenyl carbonate in the presence of a specified compound. ;CONSTITUTION: The powder is obtained by polycondensing 1 mol of 2,2-bis(4- hydroxyphenyl)propane with 0.98-1.20mol of diphenyl carbonate in the presence of phenyl phosphate and/or its salt and crystallizing the product by solvent treatment. This powder has a number-average molecular weight of 1000-20000, a crystalline melting point of 180-320°C as determined with a differential scanning calorimeter at a temperature rise rate of 20°C/min and a degree of crystallinity of 5-75%. A polycarbonate obtained by reacting this powder by heating undergoes less thermal deterioration and coloration and the worsening of the properties as compared with a polycarbonate obtained by the conventional melt polymerization process.;COPYRIGHT: (C)1994,JPO&Japio