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Expired Canadian patentCanada

Block copolymer and method of preparing same

CA 1301974 C · Owner: Willis, Carl L. · Inventors: Willis, Carl L.

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Abstract From the Canadian patent

A modified unsaturated polyester useful in preparing molded products having improved impact resistance and surface characteristics is prepared as a block copolymer comprising at least one polyester block and an elastomeric block. The modified unsaturated polyester is prepared by reacting an elastomeric polymer having at least one terminal functional group selected from the group consisting of carboxyl groups hydroxyl groups and mixtures thereof with either a preformed unsaturated polyester, thereby producing the modified unsaturated polyester directly or with monomer useful in preparing an unsaturated polyester and thereafter growing the unsaturated polyester via condensation of additional …

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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 May 26, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 26, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledSeptember 12, 1988
GrantedMay 26, 1992
Term endedMay 26, 2009
Patent numberCA 1301974 C
Classification (IPC)C08G81/02 +2 more

Timeline

Timeline From CIPO dates

1989199219951998200120042007Application filedSep 12, 1988Patent grantedMay 26, 1992Term endedMay 26, 2009

Sources & verification

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