Process for the production of high molecular weight polyester resins
CA 2083281 C · Owner: Ghisolfi, Guido · Inventors: Ghisolfi, Guido
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for the solid state upgrading of a polyester resin by polyaddition reaction in which the resin is upgraded in the presence of an upgrading additive which is a compound different from a dianhydride of an aromatic tetracarboxylic acid containing two groups capable of addition reactions with the terminal groups of the polyester, selected for example in the group of the dianhydrides of aliphatic and cycloaliphatic tetracarboxylic acids.
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 March 26, 1992 and granted June 13, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 26, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 26, 2014.
- 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.