Concurrent addition process for preparing high purity epoxy resins
CA 2005086 C · Owner: Liao, Zeng-Kun · Inventors: Wang, Chun S.; Liao, Zeng-Kun
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Epoxy resins which are relatively low in total bound halide are prepared by either concurrently and continuously or concurrently and intermittently adding (1) a mixture of an epihalohydrin, a compound containing an average of more than one group reactive with a vicinal epoxide group and a solvent and (2) an aqueous or organic solution of an alkali or alkaline earth metal hydroxide or manganese hydroxide; to (3) a mixture of epihalohydrin and a solvent.
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 December 11, 1989 and granted February 27, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 11, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 11, 2011.
- 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.