Removal of vinylpyrrolidone from vinylpyrrolidone polymers
CA 1287946 C · Owner: Basf Aktiengesellschaft · Inventors: Urban, Dieter; Sanner, Axel; Nuber, Adolf
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Vinylpyrrolidone is removed from its polymers by a process in which an aqueous or alcoholic solution of the polymer is treated with an adsorbent, the adsorbents used preferably being active carbon, zeolites and especially acidic ion exchangers.
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
- Granted August 20, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 20, 2008.
- 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.