06790929 is referenced by 27 patents and cites 6 patents.

This invention relates to an extrusion method preparing polycarbonates from a solution of an oligomeric polycarbonate. A mixture of bis(methyl salicyl)carbonate (BMSC), BPA and a transesterification catalyst are first equilibrated at moderate temperatures to provide a solution of polycarbonate oligomer in methyl salicylate. The solution is then fed to a devolatilizing extruder, where the polymerization reaction is completed and the methyl salicylate solvent is removed. The solution comprising the oligomeric polycarbonate can also be pre-heated under pressure to a temperature above the boiling point of methyl salicylate and subsequently fed to a devolatilizing extruder equipped for rapid flashing off the solvent. The method provides polycarbonate with greater efficiency than the corresponding process in which unreacted monomers are fed to the extruder. Additionally, the method of the invention does not require the isolation of a precursor polycarbonate comprising ester-substituted phenoxy terminal groups.

Title
Method for making an aromatic polycarbonate
Application Number
10/389009
Publication Number
6790929 (B2)
Application Date
March 17, 2003
Publication Date
September 14, 2004
Inventor
Paul Russell Wilson
Latham
NY, US
Paul Michael Smigelski Jr
Schenectady
NY, US
Narayan Ramesh
Niskayuna
NY, US
James Day
Scotia
NY, US
Alberto Nisoli
Niskayuna
NY, US
Patrick Joseph McCloskey
Watervliet
NY, US
Mark Howard Giammattei
Selkirk
NY, US
Norberto Silvi
Clifton Park
NY, US
Agent
Patrick K Patnode
US
Andrew J Caruso
US
Assignee
General Electric Company
NY, US
IPC
C08G 64/00
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