Solubilisation of dyes by surfactant micelles. Part 5: Durability of dye fixatives

A number of direct and indirect techniques have been used to explore the durability of dye fixatives on laundering with anionic detergent formulations. The most useful technique for quantifying fixative loss was found to be UV spectroscopy but this is not applicable in every case. Overall, it was found that the fixatives examined were durable to six washes in a typical colour-care detergent formulation at 40degreesC. It is concluded that a major contribution to dye loss from fixed cloth at low temperature is the displacement by anionic, surfactant of dye bound to the fixative. In addition to being more substantive, good quality fixatives may compete more effectively for dye and may physically entrap the dye within the fibre.