Production of lignosulfonate additives.

摘要

A method of producing a lignin dispersant composition comprising the steps of methylolating a lignin compound by reaction of less than about 2 moles formaldehyde 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 DEG 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 dey compositions and carbon black compositions with lower viscosity and extended shelf-life storage of the composition.