Process for bleaching chemical pulps with low organic halogen compounds content
CA 2372069 C · Owner: Pasquali, Silvia Maria · Inventors: Tedeschi De Araujo, Guilherme Antonio; Pasquali, Silvia Maria
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention refers to a process for bleaching chemical pulps comprising a step of adding chlorine dioxide in a pH in the range of about 4.5 to 5.5 as the first bleaching stage. The process of the present invention provides for obtaining contents of organic halogen compounds in the final pulp product lower than 30 ppm and for a reduction in the H2O2 needed for the subsequent stages.
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 April 27, 2000 and granted June 21, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 27, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 27, 2022.
- 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.