Process for increasing stain-resistance of cationic-dyeable modified polyamide fibers
CA 2255647 C · Owner: E.I. Du Pont De Nemours And Company · Inventors: Sun, Yanhui
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to an improved process for dyeing cationic-dyeable polyamide fibers especially carpet fibers, with an acid dye to provide stain-resistant fibers. The polyamide fibers contain cationically dyeable sulfonate groups along the polymer chain. The improvement involves adding certain water-soluble salts to a dyebath at a concentration of at least 20 % based on the weight of fiber.
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 May 16, 1997 and granted April 9, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 16, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 16, 2019.
- 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.