The Effect of Aftertreatments on the Fixation Ratio and Total Extent of a Reaction of a Difluorochloropyrimidine Dye on Wool

The difference between fixation ratio and extent of reaction in reactive dyeing of wool is explained. Methods of Aftertreatment of deep colours have been examined as a means of improving these values. Increases in the extent of reaction in reactive are favoured by high levels of exhaustion as well as by prolonging the time at the dyeing pH. The fixation ratio is improved by desorbing the unfixed dye, and this has been done by raising the pH at the end of the dyeing. The pH at the temperature of the aftertreatment was found to have a critical effect on thev effeciency of the process, the best results being obtained with buffer treatments, whereas with the usual ammonia aftertreatment, in which the pH was found to decrease with time, the results were much less effective. On Hercosett 57-treated wool the effect was bigger than on untreated wool