Expired Canadian patentCanada
Method for preparing n-sulfomethyl acrylamide, acrylic acid terpolymers from polyacrylonitrile
CA 1293583 C · Owner: Fong, Dodd Wing · Inventors: Vallino, Barney, Jr.; Fong, Dodd Wing
Overview
Drawings and full text
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
N-sulfomethyl acrylamide, acrylamide acrylic acid terpolymers are prepared by reacting polyacrylonitrile, water and sodium formaldehyde bisulfite at a temperture of at least 100°C.
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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 24, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 24, 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.
FiledOctober 6, 1987
GrantedDecember 24, 1991
Term endedDecember 24, 2008
Patent numberCA 1293583 C
Classification (IPC)C08F8/34 +2 more
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.