The clearing of poly(lactic acid) fibres dyed with disperse dyes using ultrasound: Part 3

The effectiveness of an ultrasound-assisted, ECE detergent-based aftertreatment was found to be little improved by the use of temperatures higher than 60 °C, durations longer than 5 min and detergent concentrations greater than 2 g l−1. As little difference was found between the effectiveness of the detergent aftertreatment and that of the traditional reduction clearing process, it appears that, in terms of fastness and colour, the Na2CO3 and Na2S2O4 used in the reduction clearing of disperse dyed PLA fibre can be replaced with a treatment using 2 g l−1 ECE detergent in the presence of ultrasound. This alternative aftertreatment of dyed PLA may offer a reduced risk of hydrolytic damage to the fibre as well as reduced chemical consumption and also generate a more environmentally acceptable effluent than reduction clearing.