Method for the manufacture of aromatic polycarbonate
AssigneeGeneral Electric Company
InventorsKenichi Tominari, Akio Kanezawa, Takeshi Sakashita, Kimiyoshi Miura, Tomoaki Shimoda
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Abstract
Aromatic polycarbonates manufactured by polycondensation of a dihydric compound and a carbonic acid diester using at least two reactors in series have improved color and low impurities content when filtered before the final reactor and again before the final reactor outlet.
Claims3
An improved method for manufacturing an aromatic polycarbonate by melt polycondensation of a dihydric aromatic compound and a carbonic acid diester wherein the polycarbonate melt is formed in at least two reactors in series, one of which is a final reactor, wherein the improvement comprises filtering the melt before the final reactor through a filter having an absolute filtration accuracy above 0.5 .mu.m but below 5 .mu.m and filtering the melt at the final reactor outlet through a filter having an absolute filtration accuracy above 5 .mu.m but below 30 .mu.m whereby the polycarbonate is suitable for optical applications or precision parts.
Dependencies are inferred from the claim text.