Method for fractionating poly(ethylene oxide) formed using a metallic cyanide catalyst
CA 2376201 A1 · Owner: Walker, Louis L. · Inventors: Clement, Katherine S.; Walker, Louis L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A poly(ethylene oxide) polymer having low and high molecular weight fractions is fractionated by dissolving the polymer in a solvent for the low molecular weight fraction. A good separation of the low and high molecular weight fractions can be obtained. When the poly(ethylene oxide) polymer contains a metal cyanide catalyst, this process also provides a good separation of the catalyst from the low molecular weight fraction. In this instance the , catalyst remains active and the high molecular weight fraction containing the catalyst can be recycled into subsequent polymerization processes.
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 July 7, 2000. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended July 7, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 7, 2022.
- 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.