Studies On The Dyeing Behavior Of Poly (Trimetylene Terephthalate) Fiber

Poly(trimetylene terephthalate) (PTT) fiberr as one of new polyester fibers which has good extensibility, high elastic resilience, soft handle, good dyeability, resistance to soiling, is widely used as new textile material with prospect. The research on its dyeing performance and mechanism provide both a theoretical basis for its development and application and a guideline for its dyeing and finishing process. At present, the literature on the dyeing performance and mechanism of PTT fiber is few. In this paper, The influence of heat set and dyeing on the structure of PTT fiber was investigated by FT-IR, DSC, critical dissolution time (CDT). The influence of heat set on the dyeability of PTT fiber was discussed, too. Meanwhile, many experiments on the dyeing performance of PET fiber were carried out. The effect of different dyeing temperature on the uptake and visual color depth value and dyeing characteristics of different dyes with temperature increasing were discussed, and the influence of temperature on the dyeing depth were also evaluated when dyeing for PTT and PET fiber in the same dye bath condition. Especially the kinetics and thermodynamics of dyeing with disperse dyes were mainly studied. Through these investigations, the results showed:The heat set increases the cystallinity of PTT fiber. The dyeability of PTT fiber first increases and then decreases with an increase in the heat set temperature, that of the sample heatset under 170℃ is lowest. The disperse azo dyes with high molecular weight are very sensitive to the difference of fine structure of fiber induced by heatset treatment. Different disperse dyes exhibit different influence styles and degrees on the structure of PTT fiber. During the dyeing , the disperse anthraquinone dyes with low molecular weight promote the decrystallization of PTT fiber, decrease the crystallinity, And moreover, the higher the concentrations of dyes are, the greater the influence on the fine structure is.PTT fiber has the better dyeability than PET under low temperature and its dyeing temperature is lower 20℃ than that of PET. The dyeing behaviors of disperse dyes on PTT fiber are related to the dyes structure and fiber types. Its critical dyeing temperaturewere lower 15-20°C than those of PET. For low energy dyes with the smaller molecular structure and the better solubility at low temperature, their dyeing conversion temperature are lower 20°C than those of high energy dyes with large molecular sizes. The migrating behavior of disperse dyes on PTT fiber at 110°C is worse than that on PET fiber at 130°C. On the other hand, the relation between dye structure and building-up behavior is different from the PET. The heterocyclic disperse dyes have worse building-up behavior. The dyeing at high temperature with low energy level dyes is favorable to attain the solid shade effect for PTT/PET blends.The dyeing rate constant of pure dyes (C.I. Disperse Blue 56 and Orange 30) for PTT, increasing with increasing dyeing temperature, is higher than that of PET and has shorter half-dyeing time. The isotherm of pure disperse dyes on PTT fiber belong to the Nernst model and the partition coefficients decreased with increasing dyeing temperature. PTT fiber dyed with C.I. Disperse Blue 56 (low energy level) and C.I. Disperse Orange 30 (high energy level) at 110°C, still don't achieve the saturation even at the 12% owf dye concentration, while PET fiber could achieve saturation at the 10-12% owf dyes with the same dyes.