Study On The Effect Of Auxiliary On Stability To Salts And Alkalis And Dyeing Property For Vinylsulfone Reactive Dyes

Vinylsulfone reactive dye, which is a kind of important product of fine chemical industry, holds an important share in reactive dyes'market. Compared with other countries, the dye commercialized technology in our country is just at the start stage. The technology of commercial dyes involved the stability to salts and alkalis, the dyeing property. Therefore it is of vital significance to investigate the effect of auxiliary on stability to salts and alkalis and dyeing property of reactive dyes.The elimination kinetics of C.I. Reactive Blue 19 near neutral conditions and the reaction in alkaline solutions were sutdied using high performance liquid chromatography (HPLC). The results showed that the elimination reaction of C.I. Reactive Blue 19 is a second order reaction, under a certain temperature, the second order rate constant k increases with the increase of ionic strength of the solution because of salt effect. The value of k in the infinitely dilute conditions, only related to temperature, can be expressed as k=8.86×1011exp (-6604/T). The reaction activation energy is approximately 54.91kJ/mol. To avoid hydrolysis reaction and other side reaction, dyeing condition of C.I. Reactive Blue 19 that the temperature does not exceed 60℃and pH value is no higher than 9.84 should be controlled.The effect of auxiliary on stability to salts and alkalis of reactive dyes was discussed in this paper. The results showed that the dispersant can enhance the stability to salts and alkalis of reactive dyes to a certain extent and the order of improving ability is MF>CNF>NNO, MF with lower polymerization degrees can enhance stability to salts and alkalis of reactive dyes better. The stronger ability of dispersant to improve stability to salts and alkalis of reactive dyes, the more content of dispersant in reactive dyes and the smoother dye surface will be. Dispersant has the function of disaggregation for reactive dyes, the ability, which is consistent with improving stability to salts and alkalis of reactive dyes, is ordered as MF>CNF> NNO. The results above showed the reason of improving stability to salts and alkalis of reactive dyes was that dispersant combined with dyes and prevented dyes from aggregating. The study also found that dispersant had a higher critical micell concentration and did not form the micelle with dyes. Study on the leveling agent showed that the leveling agent can slightly enhance stability to salts and alkalis. Leveling agent had adsorbed negatively charged ion of dye and form the micelle resulting in the increase of critical micell concentration, which is different from dispersant.Taking the fixation as evaluating indicator, the effect of dispersant on dyeing property was also studied. The results showed that dispersant MF, NNO, CNF can suppress the hydrolysis of reactive dyes to a certain extent. The fixation increaces under the condition of small dispersant amount and decreases with the increase of dispersant amount, which is in contradiction with stability to salts and alkalis of reactive dyes. Therefore we should choose dispersant that can enhance dyeing property strongestly on the basis of meeting the requirement of the stability to salts and alkalis of reactive dyes.