Method of pretreating lignocellulosic materials prior to alkaline peroxide high yield pulping
CA 2057231 A1 · Owner: Tschirner, Ulrike · Inventors: Wilder, Harry; Tschirner, Ulrike
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention concerns high yield pulping comprising chemical pretreatments using peroxide in combination with mechanical treatment to produce pulp from chips. More particularly this, invention reduces peroxide decomposition associated with the pretreatment of chips with peroxide prior to refining of the chips by impregnating the chips with a chelant prior to peroxide impregnation. With this invention pulp having desired papermaking properties, particularly a combination of high strength and brightness is obtained with reduced chemical and energy consumption.
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 December 6, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 6, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 6, 2013.
- 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.