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

Abstract

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 40 °C. 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.

Solubilisation of dyes by surfactant micelles. Part 4: Influence of dye fixatives

“…This shows that the profi le for dye loss ( Figure 8a) and the corresponding pick-up data (Figure 8b) were generally applicable to all the fi xatives studied. Data for two potentially more effective fi xatives, Solfi x E and Indosol CR, followed a similar trend and are given in Part 5 of this series [16]. Indeed, SDS was able to remove dye from dyed cloths containing all these common fi xatives, but with varying degrees of effi ciency.…”

“…The slight darkening, or strengthening, of shade with CTAB results from its complexing with dye; this shifts the absorption maximum and increases the intensity of the band (Figure 9). The effect was much more marked than with Indosol E50 and other commercial fi xatives [16]. A more marked difference was that, unlike Indosol E50 and the other commercial fi xatives, fi xation with CTAB was ineffective when washing as a single wash with anionic surfactant.…”

“…In this case anionic surfactants may operate by displacing dye from the fi xative, an effect which depends on the relative concentrations of dye and surfactant and their relative binding energy with the fi xative. The mechanism of dye loss will be examined in a later paper in this series [16].…”

Formulation of colour‐care and heavy‐duty detergents: a review

“…These can be subdivided into polymers containing an intrinsic positive charge, for example the dimethyldiallylammonium chloride (DMDAAC) type (Alcofi x R, Croscolor F3) and those that acquire a cationic charge under application conditions by protonation, e.g. polyethylene imines (Tinofi x ECO) [19][20][21].…”

“…The detergent formulator also faces constraints due to the fact that colour-care detergents are used at lower temperatures and at low fi xative concentrations. This tends to rule out the use of reactive fi xatives, which require higher temperatures to initiate polymerisation [19]. This is particularly the case with Solfi x E, an otherwise excellent fi xative which also protects against colour loss by abrasion.…”