METHOD FOR PREPARING FINE SPHERICAL POLYCARBONATE POWDERS AND METHOD FOR PREPARING HIGH MOLECULAR WEIGHT POLYCARBONATE RESIN USING SAME

摘要

The present invention relates to a method for preparing fine spherical polycarbonate powders and a method for preparing a high molecular weight polycarbonate resin using the same. The method for preparing the fine spherical polycarbonate powders comprises the steps of: (A) polymerizing non-phosgene polycarbonate; (B) extruding amorphous fine spherical polycarbonate powders; (C) surface-crystallizing the amorphous fine spherical polycarbonate powders under the presence of a solvent and a dispersion medium; and (D) drying the surface-crystallized amorphous fine spherical polycarbonate powders. The method for preparing the high molecular weight polycarbonate resin enables preparation of polycarbonates with a wide range of molecular weights from low to high through solid state polymerization by continuously using fine spherical polycarbonate powders obtained from the previous step. The present invention provides a continuous and economically efficient process for commercial production by remarkably simplifying the polycarbonate crystallization step and surpasses the preparation limit of the high molecular weight polycarbonate, which is the biggest problem of conventional non-phosgene molten polymerization processes.