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Expired Canadian patentCanada

Stabilization of iron in aqueous systems

CA 1339404 C · Owner: Fivizzani, Kenneth P. · Inventors: Hoots, John E.; Kaplan, Roy I.; Fivizzani, Kenneth P.

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Abstract From the Canadian patent

The present invention is directed to a process for stabilizing iron hydr(oxide) in aqueous systems which comprises adding to an aqueous system in which the water contains or will contain soluble iron a polymer which contains pendant N-substituted amide functionality, including amide substituted with sulfoalkyl wherein the alkyl is of 1 to 3 carbon atoms sulfophenyl, or such groups substituted further with (poly)hydroxy.

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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 September 2, 1997. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 2, 2014.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJanuary 30, 1989
GrantedSeptember 2, 1997
Term endedSeptember 2, 2014
Patent numberCA 1339404 C
Classification (IPC)C02F5/12

Timeline

Timeline From CIPO dates

199019931996199920022005200820112014Application filedJan 30, 1989Patent grantedSep 2, 1997Term endedSep 2, 2014

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