摘要 |
Non-sulfonated lignin color reductions of over 90 percent, and in some cases as high as 95 percent, are achieved by a three-step process involving (1) methylolating or crosslinking the lignin, (2) the blocking of phenolic groups on the lignin molecule with blocking agents followed by (3) oxidation with chlorine dioxide. The light colored lignin dispersants produced by the invention process exhibit very low staining and low azo dye reduction, good heat stability, dye grinding efficiency, and dispersion stability. |