The wash-off of dyeings using interstitial water part 1: Initial studies

The extent to which a novel wash-off process using polyamide beads removed five different types of dye from three different types of fibre was similar to that achieved using conventional aftertreatments. Whilst bead wash-off and the conventional aftertreatments were of similar duration and temperature, conventional aftertreatment employed a 10:1 or 20:1 liquor ratio whereas bead wash-off used a < 1:1 liquor ratio. As vagrant dye was adsorbed onto the bead material during wash-off, the low amount of wastewater generated contained little residual dye, thereby offering the potential of reduced environmental and cost benefits. Bead wash-off did not impair the fastness of two non-metallised acid dyes on nylon 6,6 to washing at 60 °C.