Patent ID: 6248858
Filing Date: 2001-06-19
Classification: C08G

Abstract:
A method for preparing an aromatic polycarbonate which comprises:(A) contacting precursor polycarbonate pellets having a diameter in the range of about 1-5 mm with at least one non-solvent therefor, said non-solvent comprising a C.sub.1-20 alkanol in the liquid or vapor state, to produce an enhanced crystallinity precursor polycarbonate; and(B) solid state polymerizing the enhanced precursor polycarbonate in a stream of inert gas, the solid state polymerizing comprising a stage of heating at a constant temperature in the range of about 215-225.degree. C., thereby producing a polycarbonate product having a number average molecular weight, as determined by gel permeation chromatography relative to polystyrene of at least 15,000.