Ammonium lignosulfonates
US4642336A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 10, 1984 |
| Grant date | Feb 10, 1987 |
| Priority date | — |
| Expiry date | Dec 10, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08H6/00
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A method of producing ammonium salts of sulfomethylated lignins suited for use as dyestuff and coal-water slurry additives comprising of the steps of ionizing the phenol component of a lignin material by-product of the black liquor of 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 liquid medium. The washed, purified methylolated lignin material is preferably sulfonated at an acid pH level to minimize the production of electrolytes when the lignin is to be used for dyeing at low pH. Lignin products produced by the method, as well as dye and coal-water slurry compositions containing such products are also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.