METHOD OF CRYSTALLIZING LOW-MOLECULAR AROMATIC POLYCARBONATE

摘要

PROBLEM TO BE SOLVED: To provide a method of efficiently crystallizing an uncrystallized low-molecular aromatic polycarbonate while scarcely causing fusion bonding thereof, and a process for producing a polycarbonate resin having a desired intrinsic viscosity by using a polycarbonate crystallized by the method. SOLUTION: An uncrystallized low-molecular aromatic polycarbonate (preferably one produced by melt polycondensation) having an intrinsic viscosity of 0.05 to 0.38 is brought into contact with a mixture of a monohydroxy compound and water at a temperature of 65-110 deg.C to crystallize it. The crystallized material is heated at a temperature lower than the melting point under a reduced pressure or in an inert gas stream under ordinary pressure to give a higher degree of polymerization, thus producing a polycarbonate resin having a desired intrinsic viscosity.