Polymers and detergent compositions containing them
CA 2031998 C · Owner: Van Kralingen, Cornelis Gerhard · Inventors: Van Kralingen, Cornelis Gerhard; Khoshdel, Ezat
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Certain polymeric polycarboxylic acids and salts containing hydroxyl or hydroxymethyl groups in close proximity to carboxyl groups, especially poly(2-hydroxymethylacrylic) acid and its salts are, effective sequestrants of divalent and polyvalent metal ions and are useful as builders in detergent compositions.
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 December 11, 1990 and granted October 15, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 11, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 11, 2012.
- 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.