Acidic aqueous cleaning compositions
CA 2107939 C · Owner: Kong, Stephen B. · Inventors: Kong, Stephen B.; Blum, Robert L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A thickened, buffered aqueous acidic cleaning composition suitable for removing mineral deposits is provided. In one embodiment the composition comprises a weak acid and its conjugate base wherein the weak acid has a pK a of approximately 2 to 3.5 and where the composition has a pH of approximately 2 to 3.5. Organic acids such as citric acid, are particularly suited. The addition of a thickening system comprising cetyl trimethyl ammonium chloride and sodium xylene sulfonate or alkyl diphenylether sulfonate produces a viscoelastic composition in which the viscosity can be controlled by the level and/or ratio of the surfactant/counterion. Suitable stable adjuncts including fragrances dyes, …
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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 October 7, 1993 and granted January 30, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 7, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 7, 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.