PURPOSE: To obtain a polycarbonate having excellent thermal stability and hydrolyzing properties by bringing a prepared polycarbonate into contact with an organic solvent or a mixed solvent of the organic solvent and water and efficiently removing a transesterification catalyst and an organic low-molecular weight component.
CONSTITUTION: (B) A carbonic acid diester and (B) a hydroxyaryl compound are subjected to melting polycondensation in the presence of (A) a transesterification catalyst to give a polycarbonate, which is brought into contact with (D) an organic solvent (preferably acetone) or a mixed solvent of the component D/water (preferably a mixed solvent of acetone/water) in the blending ratio of (99.1/0.1)-(10/90), thus the objective polycarbonate is separated. The amount of the component D or the mixed solvent of the component D/water used is preferably 0.1-20 times as much as the polycarbonate by weight.
HAYASHI KATSUSHIGE
IURA KATSUHIRO
KAWAKAMI TSUTOMU
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