Production of lignosulfonate additives
US4892588A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 1988 |
| Grant date | Jan 9, 1990 |
| Priority date | — |
| Expiry date | Oct 24, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B67/0086
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A method of producing a lignin dispersant composition comprising the steps of methylolating a lignin compound by reaction of less than about 2 moles formuladehyde per 1,000 grams of the lignin, and sulfonating the methylolated lignin by reaction from about 2.5 to 3.5 moles of the sulfite or bisulfite compound per 1,000 grams of lignin at an initial reaction pH of below about 6.6 and at a temperature of at least about 170.degree. C., while allowing the pH of the reaction mixture to rise to a final pH of greater than 7.5 to sequentially sulfomethylate the aromatic nucleus and sulfonate the side chain of the lignin. The products of the method find particular use as dispersants in dye compositions and carbon black compositions with lower viscosity and extended shelf-life storage of the composition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.