Patent ID: 7332559
Filing Date: 2008-02-19
Classification: C08G

Abstract:
1. A method of preparing a polycarbonate resin, the method comprising: transesterifying diarylcarbonate, an aromatic dihydroxy compound, and polysiloxane in the presence of a catalyst to produce a low molecular weight amorphous polycarbonate prepolymer having a weight average molecular weight (Mw) of 1,500 to 20,000 g/mol; condensation polymerizing the low molecular weight amorphous polycarbonate prepolymer to produce a medium molecular weight amorphous polycarbonate having a Mw of 10,000 to 30,000 g/mol; crystallizing the medium molecular weight amorphous polycarbonate to produce a crystallized polycarbonate; and solid state polymerizing the crystallized polycarbonate to produce a high molecular weight polycarbonate having a Mw of 20,000 to 200,000 g/mol.