| 摘要 |
A crystallized aromatic polycarbonate having a weight average molecular weight of from 6,000 to 200,000 and having a terminal hydroxyl group content of not greater than 0.03 % by weight based on the weight of the polycarbonate is effectively produced by first heating a mixture of a dihydroxydiaryl compound comprising at least 85 mole % of a dihydroxydiaryl alkane with a diaryl carbonate to prepare a prepolymer having a weight average molecular weight of from 2,000 to 20,000 and having terminal aryl carbonate groups in an amount of greater than 50 mole %, based on the total number of moles of all the terminal groups of the prepolymer, secondly crystallizing the prepolymer and finally subjecting the crystallized prepolymer to solidstate polymerization. The crystallized aromatic polycarbonate does not contain impurities, is colorless and has excellent properties such as resistance to heat and to boiling water. Therefore, the polycarbonate is advantageously used as engineering plastics. |
