One-bath dyeing of polyester/cotton blends with disperse and bis-3-carboxypyridinium-s-triazine reactive dyes.: Part 2:: Application of substantive reactive dyes to cotton at 130°C and neutral pH

An earlier paper reported that the reactive dyes (not the disperse dyes) were responsible for the inability to achieve heavy depths of shade, when dyeing polyester/cotton blends by a one-bath process at 130 degrees C and neutral pH using reactive dyes containing a 3-carboxypyridinium-s-triazinyl group. It was shown that the poor colour yield of the bis-3-carboxypyridinium-s-triazine reactive dyes was because of their low exhaustion level at 130 degrees C and pH of 7.0-7.5. We now report the synthesis and evaluation of some bis-3-carboxypyridinium-s-triazine reactive dye structures, possessing highly substantive chromophores, as a means of obtaining high colour yield, on 100% unmercerised cotton, under the specified dyeing conditions. The technical performance of these dyes under such conditions was compared with that of selected Novacron (Cibacron) LS and Procion H-E dyes, applied under their recommended (atmospheric) dyeing conditions.