Ammonium lignosulfonates
CA 1256428 A · Owner: Westvaco Corporation · Inventors: Dilling, Peter
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method is disclosed for producing ammonium salts of sulfomethylated lignins suitable for use as dyestuff and coal-water slurry additives. The method comprises the steps of ionizing the phenol component of a lignin material by-product of black liquor from a kraft paper-making process in an alkaline liquid medium methylolating the lignin material, lowering the pH of the liquid medium to an acid pH to precipitate the methylolated lignin material, washing the precipitated lignin material with water to remove inorganic salts and residual reactants therefrom, and sulfonating the washed purified methylolated lignin material with an ammonium salt of a sulphur-oxygen containing compound in a …
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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 June 27, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 27, 2006.
- 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.