Stainless steel alkali treatment
CA 2200615 C · Owner: E.R. Squibb & Sons, Inc. · Inventors: Shah, Sadiq; Kirchner, Fred
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention includes a method for cleaning and passivating a stainless steel surface comprising: 1) contacting the surface with 15-45 ml/liter of a composition comprising between about 15 and 50 % alkaline component between , about 1 to 15 % chelant, and between about 35 to 84 % water; 2) maintaining contact to dislodge and remove residue from the surface; 3) continuing contact to complex free iron ions liberated from the surface with the chelant to form an oxide film on the surface; and 4) continuing contact to precipitate the complexed ions into the oxide film. The compositions may further include a surfactant selected from the group consisting of anionic cationic, nonionic , and …
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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 September 22, 1995 and granted November 28, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 22, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 22, 2017.
- 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.