High Temperature Stability And Leveling Properties Of High-Strenth Liquid Disperse Dyes

Because disperse dyes exhibit low water solubility, a large quantity of additives and their complexes are added in the commercial processing. However, the dispersant dosage is often as high as two thirds in commercial disperse dyes, which results in relatively high COD values of the dyeing effluents and other environmental problems when the additives are discharged with the dyeing wastewater into the river and seas. Reducing the concentration of these additives (surfactants) is the most effective method to resolve these environmental problems. But this would lead to agglomerate or aggregate during the dyeing process, which results in uneven dyeing, degradation of color fastness, precipitation and so forth. Besides, because of the high temperature & pressure, stain and color point may occur easily in the dyeing of polyester fiber with disperse dyes; thereby they affect the leveling property and dyeing quality of fabrics.In the case of high-temperature stability, this paper compared several traditional anionic dispersants with sodium lignosulfonate on their grinding efficiency and their high-temperature stability to disperse dye. The anion dispersant with excellent application performance was chosen, and then the purity and sulfonation degree of sodium lignosulfonate were analyzed. The solubilization capacity of nonionic surfactants for C.I. Disperse Red 60 was measured by polymer thin-film bag method, and their effect of solubilization capacity on dyeing levelness was also studied. Through analyzing some influencing factors such as the structures of nonionic surfactants, their concentrations and so on, the relevance between the structures of nonionic surfactants and leveling properties was set up. Then high-strength liquid disperse dye was prepared by employing the chosen anion dispersant and nonionic leveling agent, and the application performance of the high-strength liquid disperse dye was further studied, with a view to reduce the environment pollution.The results showed that sodium lignosulfonate had greater effect on the high-temperature stability of dyes, and the high-temperature stability of dyes with different sodium lignosulfonate in the following order:1#>5#>8#>7#>2#>3#>6#>4#. The purity of the eight lignosulfonate was an important factor affecting the high temperature stability, in addition, the higher the sulfonation degree within a certain range as well as the higher the purity of the sodium lignosulfonate, the better the high temperature stability of the dispersion. The solubilization efficiencies of nonionic surfactants used decreased in the following order at 130℃:Tween20>Peregal O>Tween 60> NP 40> PE 6800> F127> MPEG 750> MPEG 2000. The solubilization capacity of nonionic surfactants was an important parameter affecting dyeing behaviour. Both high uptake and good dyeing levelness could be achieved under solubilizing capacity of 20mg/L-50mg/L by using nonionic surfactants. Adding strict amount of nonionic dispersant with purified sodium lignosulfonate, high-strength liquid disperse dye was prepared, then high temperature stability and dyeing property of the dye, the absorbance of the dyeing effluents were compared with commercial dyes. The results indicate that the high-temperature stability of the dye reached the level of commercial dyes. In addition, the high-strength liquid disperse dye bath showed a little greater dyeing depth than commercial dyes on the polyester, and the absorbance of the dyeing effluents was much lower than that of commercial dyes. This research can provide potential method for the existing environmental problem in polyester dyeing industry.