Method for preparing low electrolyte sodium lignosulfonates
US4740590A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 17, 1986 |
| Grant date | Apr 26, 1988 |
| Priority date | — |
| Expiry date | Jan 17, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09D17/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
An improved method of producing sodium salts of low electrolyte-containing lignosulfonates suited for use as dye and print paste additives, comprising the steps of (1) methylolating a sodium salt of a lignin compound in an alkaline aqueous medium by the addition of a suitable methylolating component, such as formaldehyde, (2) adding sulfur dioxide to the methylolated lignin in aqueous medium to lower the pH of the lignin to a pH of between about 6.1 to 6.3, (3) heating the resultant aqueous composition containing the methylolated lignin to sulfonate the same by reaction with a sulfur-containing compounds present therein. Resultant sodium salt lignosulfonate products suitable as additives in dyestuffs and dyestuff compositions containing such additives are disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.