Chemical treatments in bleaching stages which increase pulp brightness
CA 1137256 A · Owner: Nalco Chemical Company · Inventors: Hyde, James A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for increasing the final brightness of pulp contaminated with iron or manganese in a chlorine bleaching process of the type comprising one or more allcaline stages which comprises treating the pulp with at least 0.1 lbs. per ton of a water-soluble chelating agent.
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 December 14, 1982. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 14, 1999.
- 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.