Synthesis And Dyeing Properties Of Red Reactve Dyes Containing Bifunctional Groups

Reactive dyestuff plays an important role in the dyeing process of cellulose fiber. In its developing process, reactive dyes replace vat dyes, direct dyes and sulfur dyes, due to its distinctive advantages in synthesis, cost and color atlas. As one of the three primary colors, the red reactive dyes are widely used in the textile industry. However, some dyeing properties of reactive dyes, such as low dyeing exhaustion and fixation, bad dyeing fatness and large salt consumption, can lead to serious environmental problems.Thus, in order to solve these problems, high-performance reactive dyes are designed based on its relationship between the molecular structure and dyeing properties performance. All these molecular structures are designed to get an optimum balance in molecular weight, coplanarity and symmetry, etc.In accordance with the relationship between structure and properties of reactive dyes, seven red reactive dyes were designed and synthesized based on H-acid and y-acid intermediates. According to the difference in reactant, the reactive conditions of condensation and diazo coupling were adjusted. The optimized synthetic processes were elaborated in this paper. These dyes and raw materials were characterized by Vis-UV, FT-IR.The dyeing properties of the seven synthesized red reactive dyes for cotton fabrics were investigated. The stabilities of D-1, D-3, D-4and D-7to the changes of electrolyte were discussed. The results show that when sodium sulphate was20g/L, the fixation rates of D-3and D-4were almost equaled to that under the conventional dyeing condition. And the fixation rate of reactive dye without sodium sulphate was just slightly lower than that with the conventional method. So, reactive dyes, D-3and D-4could be used as low-salt dyes or salt-free dyes. The fastness test showed that all the seven red reactive dyes for cotton fabrics could meet the application requirements. The light fastness of D-6was outstanding and reached5-6.Comparison with their dyeing characteristics parameter S, E, R and F, reactive dyes, D-1and D-3were mixed at different proportion, as well as the D-4and D-7. The best proportions were respectively1:2and1:4according to the color depth, color tone and lifting power. Two mixture dyes, named red reactive A and red reactive B, were prepared. The mixture dyes had excellent application for cotton fabrics.