Patent ID: 6887968
Filing Date: 2005-05-03
Classification: C08G

Abstract:
1. A process for making a high molecular weight (co)polycarbonate resin comprising (i) obtaining at least one member selected from the group low molecular weight residue (weight average molecular weight 15,000 to 30,000) of aromatic (co)polycarbonate production, waste of (co)polycarbonate production, remainders of (co)polycarbonate production and (co)polycarbonate recyclate (ii) melting said at least one member in a suitable vessel to obtain a melt and (iii) feeding the melt into a suitable reactor operated batch-wise or continuously, optionally along with at least one bisphenol or oligocarbonate having terminal OH groups and further optionally with a transesterification catalyst, and (iv) subjecting the melt to transesterification reaction at a temperature of 250 to 350° C., at a pressure below 5 mbar and residence time of 0.02-4 hours, to obtain high molecular weight (co)polycarbonate resin.