Superabsorbent crosslinked ampholytic ion pair copolymers
CA 2043661 C · Owner: Phillips Petroleum Company · Inventors: Hsieh, Henry L.; Ahmed, Iqbal
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention provides crosslinked ampolytic copolymers that are highly absorbent to aqueous electrolyte solutions. The polymers of the present invention comprise copolymers formed by the copolymerization of an effective amount of each of the following components to produce a polymer which is highly absorbent to aqueous electrolyte solutions:, (a) an ampholytic ion pair monomer comprising (i) the ammonium cation, 3-methacrylamidopropyldimethylammonium and (ii) a sulfonate anion selected from the group consisting of 2-acrylamido-2-methylpropane sulfonate 2-methacryloyloxyethane, sulfonate, vinyl sulfonate styrene sulfonate and combinations of two or more thereof;, (b) at least one …
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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
- Filed May 31, 1991 and granted August 27, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 31, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 31, 2013.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.