Hydrophobic polyelectrolytes used in color removal
CA 2100528 A1 · Owner: Nalco Chemical Company · Inventors: Ramesh, Manian; Finck, Martha R.; Shetty, Chandrashekar S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A hydrophobic polyelectrolyte copolymer which is useful in the removal of color in paper mill waste water. The copolymer preferably comprises an acrylamide and a hydrophobic monomer selected from the group consisting of quaternized dimethylaminoethylacrylates and quaternized dimethylaminoethylmethacrylates.
Read the whole patent
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 July 14, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended July 14, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 14, 2015.
- 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.