The role of auxiliaries in the immersion dyeing of textile fibres: Part 11 residual inorganic electrolyte levels present during the wash-off of commercial grade reactive dyes

When both 2% omf and 5% omf dyeings on cotton were produced using three commercial grade reactive dyes in the complete absence of added inorganic electrolyte, a substantially modified wash-off process could be used in which both the number of wash-off baths and the liquor ratio utilised for each wash-off bath could be reduced. Measurements of the chloride ion concentration of residual dyebath, wash-off bath and final rinse bath liquors revealed that the reason why such a modified wash-off process could be utilised is due to the inherently very low dye-fibre substantivity that exists within the dyed substrate that results from the absence of added NaCl or Na2SO4 in dyeing.