Study on the Dyeing Properties of a Novel Reactive Dye with One Vinylsulfone Reactive Group, on Cotton Substrates, Before and After Its Ultrafiltration Treatment

Reactive dyes are widely used in the textile industry due to their versatility of shades, high wash fastness properties, and the ease of application. Dyeing properties such as exhaustion, substantivity, fixation, time to half dyeing, migration index and effect of metal salts were studied for a novel reactive dye (named RR Na ) synthesized with one vinylsulfone as reactive group. The aim of this study is to figure out the influence of the ultrafiltration process this dye went through on its aforementioned properties. It was found that the ultrafiltrated reactive dye shows higher exhaustion, substantivity, dye uptake than the original dye, which is attributed to the purification performed by the ultrafiltration process. The migration index is slightly lower for the ultrafiltrated dye which indicates that its mobility is lower, due to the possible formation of more covalent bonds between the dye and the substrate. The effect of metals (Fe, Co, Cu) was also studied and the color strength of the dyeings in the presence of sulfate salts was compared with the control sample. It was found that Co 2+ and Cu 2+ have a detrimental effect on the shade obtained, whereas Fe 3+ reduces color strength to a lower extent.