| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a polycarbonate resin having excellent hue, transparency, heat resistance, weatherability and mechanical strength and containing little amount of residual low molecular components.SOLUTION: The method for producing a polycarbonate resin includes a step for evaporating and removing residual low molecular components in a polycarbonate resin, obtained by subjecting dihydroxy compounds containing a dihydroxy compound having a part represented by formula (1), mentioned below, and a diester carbonate to melt polycondensation, by melt-extruding the polycarbonate resin by using a vent-type twin screw extruder 15a. The method for producing the polycarbonate resin satisfies all specific extrusion conditions. In the method, the polycarbonate resin discharged from a final reactor is supplied to the extruder in a molten state without being solidified, and the polycarbonate resin discharged from the extruder is supplied to a filter in a molten state without being solidified to filtrate foreign matters. A phosphorus-based compound is added at an upstream of a vent of the extruder. |
