Method for removing coatings from metal substrates prone to corrosion or deterioration
CA 2074545 C · Owner: Brent Chemicals International Plc · Inventors: Whitton, Colin A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a method for removing coatings, in particular, organic coatings from metal substrates which are easily corroded or discoloured: aluminimum, aluminium alloy, zinc or zinc alloy. Previously known compositions for this purpose were based on methylene chloride which is environmentally undesirable. In contrast, this invention uses a composition which comprises strong alkali a polyhydric, alcohol or ether derivative thereof and a pyrollidone and, or a lactone. The preferred pyrollidone is N-methyl pyrollidone.
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 July 23, 1992 and granted October 1, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 23, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 23, 2014.
- 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.