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Expired Canadian patentCanada

Synthetic slate

CA 1073141 A · Owner: Kumal Associates (A Partnership) · Inventors: Kuehn, Melvin C.

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

A solid, slate-like product a composition and method of, producing the same comprising a substantially uniform mixture of at least five parts by weight of a finely divided taconite iron ore material containing at least about 1 percent magnetite therein and an amine-formaldehyde resin such as urea-formaldehyde or melamine-formaldehyde. The mixture, heated under pressure forms a dense slate-like material.

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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 4, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 4, 1997.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Filed—
GrantedMarch 4, 1980
Term endedMarch 4, 1997
Patent numberCA 1073141 A
Classification (IPC)C08K3/22 +2 more

Timeline

Timeline From CIPO dates

198119831985198719891991199319951997Patent grantedMarch 4, 1980Term endedMarch 4, 1997

Sources & verification

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