Fibers of sulfonated poly(p-phenylene terephthalamide)
CA 2029477 C · Owner: E.I. Du Pont De Nemours And Company · Inventors: Chiou, Minshon J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Fiber made from PPD-T with 0.5 to 3.0% sulfur as bound sulfonic acid or sulfonate groups is, disclosed. The fiber has inherent viscosity greater than 9.5, yarn tenacity greater than 20 grams per denier, heat-aged strength retention of greater than 90%, and dipped cord strength greater than 18 gram per denier. The process for making the fiber includes PPD-T sulfonation by exposure to high concentration sulfuric acid in dope preparation under carefully controlled temperature and time.
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 7, 1990 and granted July 25, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 7, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 7, 2012.
- 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.