Dyeing properties on polyurethane fibres of novel azo disperse dyes prepared from a four-component Ugi reaction

A new group of azo disperse dyes prepared by the Ugi four-component reaction were used to dye polyurethane fibres. It was found that all the new dyes showed excellent fastness properties. One of the new dyes was selected to investigate the adsorption properties on polyurethane fibres, including the dyeing rate, adsorption isotherm, surface adsorption state, colour characteristics and colour fastness. The results were compared with those of CI Disperse Orange 3, which has the same parent structure as the new dye. The results indicated that the new dye has a lower dyeing rate and solubility but a higher affinity and adsorption capacity than the conventional dye due to its larger molecular weight and size. In addition, the aggregation of the new dye on the surface of polyurethane fibres occurred at higher concentrations whereas the conventional dyes aggregated at a lower concentration, resulting in lower colour fastness. This demonstrates that these new dyes derived from the Ugi four-component reaction are worth developing further and are of great application value for polyurethane fibres.