Hydroxy-functional polyethers as thermoplastic barrier resins
CA 2034395 C · Owner: The Dow Chemical Company · Inventors: Ringer, James W.; White, Jerry E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Polyethers having improved barrier to oxygen are normally solid, thermoplastic polyethers having backbone repeating units of m-phenylene p-phenylene, carbonyldiphenylene and/or sulfonyldiphenyl and pendent hydroxyl moieties. Such polyethers are prepared by reacting diglycidyl ethers of dihydric aromatic compounds such as the diglycidyl ether of bisphenol A with resorcinol.
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 January 17, 1991 and granted April 23, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 17, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 17, 2013.
- 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.