Abstract: A process for introducing additives into a polymer melt comprising dispersing at least one additive in an at least partially volatile liquid vehicle with a dispersant and a stabilizer for the dispersion; feeding the resulting dispersion to a vented extruder which is extruding a polymer; and removing the fed volatiles through the extruder vent to achieve a substantially homogeneous system containing the polymer and at least one additive is disclosed.

Abstract: Dyestuff compositions are provided which incorporate, as the grinding aid and/or dispersant therefor, amine modified lignin admixed with sulfonated lignin. The disclosed dyestuff compositions exhibit improved heat stability and, as a result of the higher activity of the dispersant mixture of amine modified lignin blended with sulfonated lignin, less dispersant is present in the exhaust liquor and waste treatment demands are thereby reduced. The improved package dyeing grinding aid/dispersant of the invention is prepared by mixing an amine modified lignin with a sulfonated lignin.

Abstract: Dyestuff compositions are provided which incorporate amine modified sulfonated lignins. The disclosed dyestuff compositions exhibit improved heat stability and, as a result of the higher activity of the amine modified sulfonated lignin, less dispersant is present in the exhaust liquor and waste treatment demands are thereby reduced. The presence of tertiary amine groups in sulfonated kraft, sulfomethylated kraft, and sulfite lignins provide dispersants with package dyeing heat stabilities significantly better than those of the unmodified lignins. The improved package dyeing grinding aid/dispersant of the invention is prepared by reacting sulfonate lignin with a secondary amine using formaldehyde and alkaline conditions.

Abstract: The invention relates to a process for dyeing synthetic or natural polyamide fibers with anionic dyestuffs, comprising (i) bringing the polyamide fibers into contact with an aqueous dyeing liquor which contains in addition to one or more dyestuffs a cationic dyeing assistant having affinity for anionic polyamide dyestuffs, and dyeing the polyamide fibers at a temperature of from 60.degree. to 105.degree. C., and (ii) adding an anionic dyeing assistant to the dyeing liquor 15 to 60 minutes after reaching the dyeing temperature, to complete the dye exhaustion. Surface and fibre level dyeings with a good dye penetration are thus obtained.