A method in ozone bleaching of pulp
CA 2116974 A1 · Owner: Brannland, Rolf Carl August · Inventors: Noreus, Sture Erik Olof; Brannland, Rolf Carl August
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
When closing the process of manufacturing cellulose pulp of high brightness, i.e. including the recovery of essentially all waste liquor, there is an untenable enrichment of certain basic elements, such as sodium and sulphur. The present invention provides a partial solution to this problem and is concerned with a method in bleaching with ozone lignocellulosic material (cellulose pulp) which has been at least partially manufactured chemically in the , presence of water at a degree of acidity expressed as pH, of, 2-5. The method is characterized in that the acidity is maintained during the ozone bleaching process by adding a sulphuric acid solution or an acid sodium sulphate solution …
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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
- Filed September 16, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended September 16, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 16, 2014.
- 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
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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.