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Expired Canadian patentCanada

Two stage process for the production of molded articles

CA 1328946 C · Owner: Bayer Aktiengesellschaft · Inventors: Uerdingen, Walter; Muller, Hanns Peter; Heine, Heinrich

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Abstract From the Canadian patent

Molded articles are produced in a two-stage process. In the first stage, an organic polyisocyanate is reacted with an organic compound containing at least two epoxide groups (NCO: epoxide equivalent ratio of 1.2:1 to 500:1) in the presence of a tertiary amine catalyst. This reaction is stopped when no more than 65% of the isocyanate groups have reacted by adding an alkylating sulfonic acid alkyl ester of methyl iodide and/or of dimethyl sulfate in an amount equivalent to the amount of tertiary amine catalyst present. A latent catalyst capable of being activated by heat is subsequently added to the intermediate product and the resultant mixture is heated in a mold to complete the …

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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 April 26, 1994. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 26, 2011.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 8, 1987
GrantedApril 26, 1994
Term endedApril 26, 2011
Patent numberCA 1328946 C
Classification (IPC)C08G18/00 +2 more

Timeline

Timeline From CIPO dates

19881991199419972000200320062009Application filedDec 8, 1987Patent grantedApril 26, 1994Term endedApril 26, 2011

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