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Expired Canadian patentCanada

Process for preparation of water absorptive composite

CA 1302181 C · Owner: Shibano, Takeshi · Inventors: Shibano, Takeshi; Itoh, Kiichi

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Abstract From the Canadian patent

A process for preparing a water absorptive composite consisting of a highly water absorptive polymer and a prefabricated fibrous substrate, which comprises applying an aqueous solution containing (a) a polymerizable monomer comprising as a main component acrylic acid of, which 20% or more of the carboxyl groups have been neutralized to its alkali metal salt or ammonium salt (b) 2-vinylpyridine or(and) 4-vinylpyridine or(and) their salts, (c) a crosslinking agent and (d) an oxidative radical polymerization initiator to a prefabricated fibrous substrate, and then carrying out polymerization with addition of a reducing agent.

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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 2, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 2, 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.
FiledMay 26, 1988
GrantedJune 2, 1992
Term endedJune 2, 2009
Patent numberCA 1302181 C
Classification (IPC)D06M14/04 +2 more

Timeline

Timeline From CIPO dates

1989199219951998200120042007Application filedMay 26, 1988Patent grantedJune 2, 1992Term endedJune 2, 2009

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