PROCESS FOR PREPARING POLYCARBONATE AND APPARATUS FOR PREPARING POLYCARBONATE

摘要

A process for preparing an end-capped polycarbonate comprises melt reacting an aromatic dihydroxy compound, a carbonic acid diester, and optionally a catalyst in a prepolymerization vessel 4a/4b to form a polycarbonate product; transferring the polycarbonate product from the prepolymerization vessel 4a/ab; mixing the polycarbonate product with an end-capping agent under hermetic seal at a pressure of at least about 76 mm Hg; and transferring the polycarbonate product and en-capping agent mixture to a postpolymerization vessel 9 to endcap the polycarbonate product. An apparatus for preparing an end-capped polycarbonate comprises a prepolymerization vessel 4a/4b having and inlet and an outlet; a postpolymerization vessel 9 having an inlet and an outlet; a mixer in fluid communication with the outlet of the prepolymerization vessel 4a/4b and the inlet of the postpolymerization vessel 9; and a charging port through which an end-capping agent is charged to the mixer, wherein the mixer is hermetically sealed at greater than or equal to 760 mm Hg.