Process and kit for dyeing hair
CA 2136459 C · Owner: Prota, Giuseppe · Inventors: Wenke, Gottfried; Prota, Giuseppe
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for dyeing hair by preparing and applying to the hair an aqueous reaction medium comprising a dopa species a, reactive direct dye and an oxidant, said aqueous reaction medium optionally containing at least one hair dyeing agent selected from the group consisting of primary intermediates and couplers and also containing a buffer to maintain the pH in the range from 6 to during the reaction, and removing said aqueous reaction medium from the hair within about one hour following its preparation.
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 November 23, 1994 and granted May 27, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 23, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 23, 2016.
- 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.