Purification of n-vinylformamide and poly-n- vinylformamides prepared therefrom
CA 1292719 C · Owner: Hartmann, Heinrich · Inventors: Kroener, Michael; Proll, Theo; Oftring, Alfred
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
N-Vinylformamide is purified by fractional distillation in the presence of formamide in a column under from 0.5 to 30 mbar by a method in which the distillation is controlled so that N-vinylformamide containing from 0.1 to 15% by weight of formamide is obtained as the distillate. Homopolymers having particularly high molecular weights can be prepared from the N-vinylformamide purified in this manner.
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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
- Granted December 3, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 3, 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
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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.