| 摘要 |
There is provided a technique for producing an aromatic polycarbonate which undergoes no deterioration in quality in a gear pump, has excellent hue and contains a small amount of foreign materials even when a production plant is scaled up. In producing the aromatic polycarbonate by melt-polycondensation, a molten polycondensate is fed continuously into a shaft seal portion of a self-lubricating gear pump disposed for transporting the polycondensate from a polycondensation vessel such that the following expressions: Q/S>=0.1 (cm/sec) wherein Q is a flow rate (cm3/sec) of the polycondensate, and S is a cross sectional area (cm2) of a passage provided for feeding the polycondensate to the shaft seal portion, and D<=2.9W1/3 wherein D is an internal diameter (cm) of a pipe, and W is a flow rate, are satisfied, thereby operating the gear pump. A polycondensation vessel therefor is also disclosed.
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