Stainless steel acid treatment
CA 2200587 C · Owner: Merck Enterprises, 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 15-48 ml/liter of an acid formulation comprising between about 1 and 60 % acid component about 1-15 % , surfactant, and between about 39 and 98 % water; 2) maintaining contact to dislodge and remove residue from the surface; 3) continuing contact to complex free iron ions liberated from the surface to form an oxide film on the surface; and 4) continuing contact to precipitate the complexed ions into the oxide film.
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 September 22, 1995 and granted February 27, 2001. 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.