Ammonia-ketone pulping process
CA 1075409 A · Owner: Weyerhaeuser Company · Inventors: De Haas, Gerrit G.; Lang, Charles J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract of the Disclosure A method of employing the combination of ammonia and ketones as the cooking chemicals in a digester of a pulping process. This method results in a pulp which has a higher yield than the kraft process yet is characterized by kraft's high strength and fair bleachability. The spent liquor extracts are primarily lignin and contain little cellulose and hemi-cellulose.
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
- Granted April 15, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 15, 1997.
- 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.