Process for extracting metal residue from poly(ether ketone ketones)
CA 2010840 C · Owner: E. I. Du Pont De Nemours And Company · Inventors: Brugel, Edward G.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Metal residues are extracted from poly(ether ketone ketones) with aliphatic alpha-hydroxycarboxylic acids or aromatic ortho-hydroxycaxboxylic acids in a liquid phase, either neat or in an aqueous or a nonaqueous solution. Extraction of metal residues which usually derive from the catalysts used in the preparation of poly(ether ketone ketones) improves, both the color and the thermal stability of these polymers.
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 February 23, 1990 and granted May 16, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 23, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 23, 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.