Production of polycarbonates
CA 1300799 C · Owner: Bp Chemicals Limited · Inventors: Hudson, Barry
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Case 6616(2), ABSTRACT OF THE DISCLOSURE PRODUCTION OF POLYCARBONATES, This invention relates to an integrated process for producing polycarbonates by transesterification of a dialkyl carbonate with a bisphenol diester to form a carbonate oligomer and an alkyl ester followed by polymerisation of the oligomer to a polycarbonate. The feature of the invention lies in the carbonylation of the alkyl ester by-product formed during the transesterification step to an anhydride which is used to esterify bisphenol to the diester.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted May 12, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 12, 2009.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.