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Expired Canadian patentCanada

Cathodic active material composition for dry cells, method for preparing the same, and alkaline battery

CA 2120269 C · Owner: Hanawa, Kenzo · Inventors: Taenaka, Sakiko; Hanawa, Kenzo; Hanzawa, Noriko

CIPO record

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Abstract From the Canadian patent

A cathodic active material comprises a mixture of graphite particles and electrolytic manganese dioxide particles which are composed of needle-like crystals having an aspect ratio ranging from about 2 to about 20 and an alkaline manganese dioxide cell is provided with a cathode prepared from the cathodic active material. The cathodic active material for dry cells can be prepared by mixing, in advance, carbon powder with manganese dioxide powder in a weight ratio ranging from about 1:100 to about 15:100 and then pulverizing the resulting mixture. The novel cathodic active material for dry cells permits substantial improvement of the resulting dry cell in the high load-discharge quality.

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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 March 30, 1994 and granted December 8, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 30, 2014.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 30, 2016.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMarch 30, 1994
GrantedDecember 8, 1998
Term endedMarch 30, 2014
Patent numberCA 2120269 C
Classification (IPC)H01M4/08 +1 more

Timeline

Timeline From CIPO dates

1995199719992001200320052007200920112013Application filedMarch 30, 1994Patent grantedDec 8, 1998Term endedMarch 30, 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.