Methods for making polymers from n-vinyl acetamide monomer
CA 2234468 A1 · Owner: Chandran, Rama S. · Inventors: Leblanc, Jean-Pierre; Chandran, Rama S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention is directed to precipitation polymerization processes for the manufacture of essentially non-crosslinked polymers prepared from N-vinyl acetamide monomer which exhibit reduced levels of residual non-polymerizable contaminants particularly residual acetamide, the, processes including the steps of contacting the N-vinyl acetamide monomer with a polymerization medium containing a diluent selected from ethyl acetate and acetone and a free-radical initiator under conditions effective to, polymerize the N-vinyl acetamide monomer thereby forming a precipitate of, the polymer in the polymerization medium; and isolating the precipitated polymer from the polymerization medium.
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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 April 8, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 8, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 8, 2020.
- 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.