Method for preparing optical-grade polycarbonate compositions

摘要

Object: The present invention was conceived in light of the above- described prior art. The object of this invention is to provide a method for preparing optical-grade polycarbonate compositions, which method is able to prepare with good productivity optical-grade polycarbonate compositions that have not only excellent clarity and water resistance, but also excellent retention stability such as heat stability and hue stability when molten and a low content of inclusions and impurities, and that undergo little heat deterioration.PP Constitution: The method for preparing optical-grade polycarbonate compositions according to this invention, which method comprises the melt- polycondensation of an aromatic dihydroxy compound and a diester carbonate in the presence of a catalyst, followed by the addition of additives [B] while the polycarbonate [A] obtained as the reaction product is in a molten state, and mixing.PPIn this invention, it is preferable to prepare the optical-grade polycarbonate composition by filtration with a polymer filter following mixing.