METHOD FOR CRYSTALLIZING LOW-MOLECULAR WEIGHT POLYCARBONATE AND METHOD FOR POLYMERIZING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a method for crystallizing a low-molecular weight polycarbonate efficiently and a method for manufacturing a polycarbonate resin having a desired intrinsic viscosity by using a polycarbonate crystallized through the above method. SOLUTION: A low-molecular weight polycarbonate (preferably, a low- molecular weight polycarbonate produced by melt polycondensation) is brought into contact with an aromatic monohydroxy compound or a mixture of the compound with water to crystallize it. The resultant crystallized carbonate is heated at a temperature lower than its melting point under a reduced pressure or in an inert gas stream to increase the degree of polymerization of the polycarbonate, and thus a polycarbonate resin having a desired intrinsic viscosity is manufactured.