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Expired Canadian patentCanada

Amine polymers having dewatering activity

CA 1135446 A · Owner: Pfizer Limited · Inventors: Sysko, Robert J.; Kurowsky, Steven R.; Glowaky, Raymond C.

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Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Amine polymers are used to dewater suspensions of particulate matter in water. The polymers are synthesized by the reaction of a nitrile polymer such as polyacrylonitrile, an aminating agent, and a sulfur activator. The dewatering properties of these amine polymers can be beneficially employed to treat sewage sludge silt laden, water, industrial waste and the like.

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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 November 9, 1982. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 9, 1999.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 3, 1979
GrantedNovember 9, 1982
Term endedNovember 9, 1999
Patent numberCA 1135446 A
Classification (IPC)C08F20/42 +2 more

Timeline

Timeline From CIPO dates

1980198219841986198819901992199419961998Application filedDec 3, 1979Patent grantedNov 9, 1982Term endedNov 9, 1999

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.