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Expired Canadian patentCanada

Polymer and its production

CA 1256638 A · Owner: Takeda Chemical Industries, Ltd. · Inventors: Ogawa, Yasuaki; Miyagawa, Tsutomu; Tanaka, Motoaki

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Abstract of the Disclosure A polymer or copolymer of lactic acid and/or glycolic acid which has a weight-average molecular weight of not less than about 5,000 and a dispersity of about 1.5 to 2 is advantageously used as a biodegradable polymer or copolymer for medical preparation.

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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 June 27, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 27, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 28, 1985
GrantedJune 27, 1989
Term endedJune 27, 2006
Patent numberCA 1256638 A
Classification (IPC)C08G63/06 +2 more

Timeline

Timeline From CIPO dates

1986198919921995199820012004Application filedJune 28, 1985Patent grantedJune 27, 1989Term endedJune 27, 2006

Sources & verification

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