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Expired Canadian patentCanada

Bipolar membrane and method for its production

CA 2043583 C · Owner: Ohmura, Nobuhiko · Inventors: Hirayama, Koki; Tanaka, Shinsuke; Hanada, Fumio

CIPO record

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

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Abstract From the Canadian patent

Disclosed is a bipolar membrane comprising a cation-exchange membrane in which a cation-exchange group present at least at its adhered surface has been ion-exchanged with a heavy metal ion, which is adhered closely to an anion-exchange membrane at a peel strength of not less than 0.2 kg f/25 mm, and having a water-splitting current efficiency of not less than 80% and a water-splitting membrane potential of not more than 2.0 V.

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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 May 30, 1991 and granted January 5, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 30, 2011.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 30, 2013.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 30, 1991
GrantedJanuary 5, 1999
Term endedMay 30, 2011
Patent numberCA 2043583 C
Classification (IPC)B01D67/00 +2 more

Timeline

Timeline From CIPO dates

1992199419961998200020022004200620082010Application filedMay 30, 1991Patent grantedJan 5, 1999Term endedMay 30, 2011

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