Preparation of a dye for coloring protein-based fibers and cellulose-based materials from the oxidation products of the manufacture of a triphenylmethane dye
CA 2246032 A1 · Owner: Dimarcello, Belinda J. · Inventors: Ellis, Gary D.; Dimarcello, Belinda J.; Bradshaw, Debra J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process of preparing a dye composition and a resultant dye composition. The process includes preparing a mixture comprising a triphenylmethane dye and oxidation products by reacting methylenedianiline aniline, an oxidation catalyst, and an oxidant; separating the oxidation products from the triphenylmethane dye to produce an aqueous solution of oxidation products; treating the solution of oxidation products with a basic compound; separating unreacted aniline from the solution of oxidation products and forming a mixture of oxidation products; and sulfonating the mixture of oxidation products to form a dye composition.
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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 29, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended September 29, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 29, 2020.
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Timeline
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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.