Low electrolyte sodium lignosulfonates

Abstract From the Canadian patent

A method is disclosed of producing sodium salts of low electrolyte-containing sulfonates suitable for use as dye and print paste additives. The method comprises the steps of ionizing the phenol component of a lignin material in an alkaline liquid medium, methylolating the ionized phenol component of the lignin material lowering, the pH of the liquid medium to the acid pH range 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 a sodium salt of a sulphur-oxygen containing compound in a liquid medium. The washed …