| 摘要 |
PURPOSE: To provide a method for producing a polycarbonate resin, capable of reducing stamper stains generated on the molding of optical disks, compact disks, etc., and capable of preventing the generation of white spots on molded products under the environments of high temperature and high humidity. CONSTITUTION: A method for producing a polycarbonate resin comprises reacting the mixted solution of an aqueous alkali-solution of a dihydric phenol with an organic solvent with phosgene. Therein, (1) the mixted solution of an aqueous alkali-solution of the dihydric phenol with the organic solvent is reacted with the phosgene, while maintaining an oil-in-water type dispersion state, and the reacted mixed solution is left standing and subjected to the separation of the phases to remove the amount corresponding to 20-85vol.% of the whole aqueous phase. (2) an aqueous solution of an alkali is added to the residual solution, and again stirred to convert the water-in-oil dispersion into an emulsion and promote the polymerization. The obtained polycarbonate resin is useful as a raw material for optical disks and compact disks which require high qualities, because of minified low mol.wt. oligomers. |
