A study of heterobifunctional reactive dyes on nylon fibers: dyeing properties, dye moiety analysis and wash fastness

Heterobifunctional reactive dyes provide great opportunity for efficient dye-fiber reaction due to the mixed double-anchors such as sulphatoethylsulphone and monochlorotriazinyl reactive groups, which may cover a wide range of application temperatures. Four heterobifunctional reactive dyes were applied to nylon fibers using various pH and temperature conditions. The optimized exhaustion (%E) and fixation (%F) were determined. Analysis of dye solutions being adjusted to different pH conditions was carried out to verify the structure of dye moieties. In addition, the acid dyeings having the similar color strength with reactive dyeings were prepared using color matching system to compare wash fastness properties of both the dyed samples. In the case of reactive dyeings, when compared to acid dyeings, the extent of reduction in color strength that occurred during repeated washings was very low and the shade of the dyeings was little changed.