Improved corrosion inhibiting formulations with calcium nitrite
CA 2211408 C · Owner: Shen, Ding Feng · Inventors: Shen, Ding Feng; Berke, Neal Steven; Hicks, Maria Caroline
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An admixture for cement compositions is provided which contributes both anodic and cathodic corrosion inhibition, and the cement compositions containing such additives. The cement additive is a combination of an anodic corrosion inhibitor such as calcium nitrite, and a cathodic corrosion inhibitor such as calcium stearate or other fatty acid. The mixed inhibitors in accordance with the invention provide as good or better corrosion inhibition than does calcium nitrite when used alone.
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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 January 24, 1996 and granted February 18, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 24, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 24, 2018.
- 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.