Dyeing properties of monoazo disperse dyes derived from 4-alkylamidosalicylic acids: equilibrium study

The dyeing equilibria of a set of monoazo dyes derived from 4-alkylamidosalicylic acids on nylon 6.6 have been studied. A Nemst distribution has been obtained indicating the prevailing mechanism of solution of the dye in the fibre Equilibrium depends on the length of the alkyl chain of the dye and on the concentration of dispersant. The latter affects the equilibrium differently according to the hydrophobicity of the dye. Linear relationships between the chain length and ΔHd and ΔSd have been found.