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Expired Canadian patentCanada

Thermochromic composition

CA 1265327 C · Owner: Matsui Shikiso Chemical Co. Ltd. · Inventors: Shimizu, Goro; Hayashi, Yoshimi

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

A thermochromic composition comprising (1) an electron-donating chromogenic material (2) a 1,2,3-triazole, compound, (3) a weakly basic sparingly soluble azomethine, or carboxylic acid primary amine salt and (4) an alcohol, amide or ester serving as a solvent.

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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 February 6, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 6, 2007.
  • 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 2, 1985
GrantedFebruary 6, 1990
Term endedFebruary 6, 2007
Patent numberCA 1265327 C
Classification (IPC)G01K11/16

Timeline

Timeline From CIPO dates

19861989199219951998200120042007Application filedJan 2, 1985Patent grantedFeb 6, 1990Term endedFeb 6, 2007

Sources & verification

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