Light fastness of bi-functional reactive dyes with pad-batch and pad-dry cure methods on cellulosic substrate

Two bifunctional reactive dyes containing two different reactive groups (sulphatoethylsulphone and monochlorotriazine) have been applied on cellulosic substrate with pad-batch and pad-dry cure methods and their light fastness was examined on Mercury Blended Tungsten Filament lamp at different time intervals. It was observed that the light fastness results obtained with pad-batch process were better than with pad-dry cure method. The colorimetric data clearly shows the extent to which the dyeing methods affect the light fastness in terms of fading of color from the original dyeings. Further, it was concluded that the addition of urea at a concentration of 100-120 g/1 exhibited pronounced effect on light fastness of the dyed fabric with pad-dry cure method.