Method for the production of fiber pulp
CA 1187657 A · Owner: Axelson, Per O. · Inventors: Axelson, Per O.; Simonson, Rune G.W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to a method for the production of fiber pulp from lignocellulosic material containing at least 70% spruce or spruce-like material. The method comprises the steps of lignin softening and defibration/refining, the step of lignin softening being performed prior to the step of defibration/refining and comprising impregnating the starting material with a dilute aqueous solution of a lignin softening agent namely a solution of sulfurous acid, metal bisulfite salts and/or metal sulfite sales in an amount sufficient to provide a defibrated/refined pulp containing an absorbed and bonded amount of sulfonate groups within the range of from 0.06 to 0.75 wt.-%, calculated as …
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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
- Granted May 28, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 28, 2002.
- 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.