A process for making a high molecular weight (co)polycarbonate resin is disclosed.
The process entails (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 the
said member in a suitable vessel to obtain a melt and (iii) feeding the melt into
a reactor 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.
