Determination of aqueous fluid surfactant concentration
CA 2229446 C · Owner: Ernst, Joseph M. · Inventors: Ernst, Joseph M.; Noble, Harold J. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A single-phase method for quantitatively measuring the anionic surfacatant content of an aqueous machining fluid is provided. The method is carried out at a pH value of from about 1.5 to about 3.0 and from about 9.5 to about 10.6 and involves the addition of an excess of a standardized aqueous solution of 1,3-didecyl-2-methylimidazolium chloride to the sample of aqueous machining fluid and then back titrating the excess 1,3-didecyl-2-methylimidazolium chloride with a standardized aqueous solution of polyvinylsulfuric acid potassium salt in the presence of toluidine blue indicator. Values of the amount of 1,3-didecyl-2-methylimidazolium chloride amount corresponding to anionic …
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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 August 4, 1997 and granted December 3, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 4, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 4, 2019.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.