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Expired Canadian patentCanada

Process for the preparation of polyester polyols

CA 1059529 A · Owner: Basf Wyandotte Corporation · Inventors: Patton, John T. (Jr.); Vogt, Herwart C.

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

Polyester polyols are prepared by the reaction of a polycarboxylic acid or anhydride with a polyhydric alcohol employing in an initial step a stoichiometric excess of polycarboxylic acid or anhydride, thereafter removing between 90% to 95% of the water of esterification adjusting the, stoichiometry of the reaction by addition of polyhydric alcohol, and continuing the esterification reaction until a polyester polyol having an acid number of less than two is obtained. The process allows for an increase in reactor capacity without equipment modification at the same cycle times and a decrease in side product formation.

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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 July 31, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 31, 1996.
  • 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—
GrantedJuly 31, 1979
Term endedJuly 31, 1996
Patent numberCA 1059529 A
Classification (IPC)C07C69/34 +2 more

Timeline

Timeline From CIPO dates

198019821984198619881990199219941996Patent grantedJuly 31, 1979Term endedJuly 31, 1996

Sources & verification

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