Some Observations on the Overdyeing of Nylon with Aggregated Acid Dyes

Dyeing in excess of the amino content of the nylon can be obtained with dyes of the Carbolan type from solutions of pH 45. This is accompanied by some hydrolysis, but insufficient to account for the whole of the dye uptake, and it is suggested that dyeing is to a large extent due to non‐ionic affinity of the dye anions. There is evidence that the dyes form micelles in solution and that this determines the maximum rate of dyeing.