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Expired Canadian patentCanada

Tertiary aralkyl urethanes and isocyanates derived therefrom

CA 1213897 A · Owner: American Cyanamid Company · Inventors: Chang, Laurence W.; Singh, Balwant; Forgione, Peter S.

CIPO record

Overview

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Abstract From the Canadian patent

Production of tertiary aralkyl isocyanates such, as tetramethyl xylylene diisocyanates by thermal cracking, of corresponding olefins and carbamic acid esters at moderate temperatures and in the presence of acid catalyst.

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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 November 12, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 12, 2003.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJuly 21, 1983
GrantedNovember 12, 1986
Term endedNovember 12, 2003
Patent numberCA 1213897 A
Classification (IPC)C08G18/76

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedJuly 21, 1983Patent grantedNov 12, 1986Term endedNov 12, 2003

Sources & verification

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