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Expired Canadian patentCanada

Cement compositions containing set retarders

CA 1234582 A · Owner: The Dow Chemical Company · Inventors: Wilson, David A.; Crump, Druce K.

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

The process of employing as a cement setting retarder a compound which is a derivative of dicyclopentadiene bis(methylamine) wherein at least one amine hydrogen is substituted with a methylenephosphonic acid group or a salt thereof the other groups being selected from a limit set of moieties. 30,727-F

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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 March 29, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 29, 2005.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 29, 1984
GrantedMarch 29, 1988
Term endedMarch 29, 2005
Patent numberCA 1234582 A
Classification (IPC)C04B24/12

Timeline

Timeline From CIPO dates

1985198819911994199720002003Application filedJune 29, 1984Patent grantedMarch 29, 1988Term endedMarch 29, 2005

Sources & verification

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