Chemimechanical pulping process employing sodium carbonate and sodium sulphite
CA 1309562 C · Owner: Valade, Jacques L. · Inventors: Law, Kwei-Nam; Valade, Jacques L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a high yield chemimechanical pulping process for producing pulp from wood chips or sawdust or other lignocellulosic materials which comprises treating said lignocellulosic material with an aqueoussolution of mixture of sodium sulphite and sodium carbonate or sodium bisulphiteand sodium carbonate sulphonating the treated material in a liquid phase or vapour phase cooking, and subsequently subjecting the resulting sulphonated material tomechanical defibration.
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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 November 3, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 3, 2009.
- 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.