Preparation of a polyethylene phthalate or a polyethylene napthalate
CA 2033213 A1 · Owner: James, David E. · Inventors: Packer, Lawrence G.; James, David E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process is disclosed for preparing a polyethylene phthalate or polyethylene naphthalate having a predetermined intrinsic viscosity which involves the direct esterification of a phthalic acid or a naphthalene dicarboxylic acid with ethylene glycol followed by the polycondensation of the esterification product using a polycondensation catalyst system containing cobalt manganese-, and, antimony-containing components.
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
- Filed May 24, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 24, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 24, 2012.
- 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.