PROCESS FOR PRODUCING POLYCARBONATE

摘要

A process for producing polycarbonate by transesterification has at least the following steps: (a) at least one aromatic dihydroxyaryl compound is reacted with a diaryl carbonate in the melt at least in the presence of a catalyst; (b) the melt produced in step (a) is mixed with a foaming agent; (c) the melt from (b) is degassed by introducing the melt into a precipitation container through inlets. The process is characterised in that degassing in step (c) is carried out by foaming, the melt being subdivided by the inlets into partial streams of 0.1 to 20 kg/h, while its temperature when entering the inlets amounts to 250 to 340 ‹C and the pressure in the precipitation container amounts to 0.1 to 20 mbar. ® KIPO & WIPO 2007