Research On Material Characterization And Dyeing Properties Of Dyeable PU With Acid Dyes

Spandex is a short name for polyurethane, it has high elasticity, high strength,abrasion resistance, excellent dyeing properties, and chemical resistance, etc, and widely used. However, when nylon/spandex, wool/spandex and silk/spandex blends were dyed, nylon can be dyed easily, but the spandex can hardly be dyed, thus produce the phenomenon of white, and affected the added value of fabric. In order to improve the dyeing properties of spandex, we study the chemical or physical modification of spandex, to the preparation of acid dye dyeable spandex, solve the problem of white. Acid dye dyeable spandex in this study was produced using the method of combining chemical modification and physical modification. Chemical modification can add a certain amount of diethylamine in extender chain ammonia material, providing more dyeing sites for acid dyes, this kind of diethylamine contains more N element of the existence of atoms in lone electron, with H+ protons, and with acid dyes; Physical modification will improve the performance of polyurethane fiber dyeing auxiliaries, and developed a dyeable spandex acid dye. And study its dyeing properties on the development of this new type of acid dye dyeable spandex is of great significance.In this thesis, in order to research on the influence of acid dye dyeable modification on the properties of spandex fiber, the modern apparatue test methods were used to analyze the morphology, chemical structure, crystallization properties,thermal properties, physical and mechanical properties of normal and modified spandex fibers. The results showed that the surface profile of dyeable spandex fiber had no difference with that of normal spandex fiber. As for the chemical structure, the amount of free group-NH increased and the hydrogen bonding-NH decreased in the dyeable spandex fiber macromolecule. Crystallinity of the dyeable spandex fiber reduced and the crystal perfection became weak. Glass transition temperature of the dyeable spandex fiber was similar with that of ordinary spandex fiber, but with thethermalproperty lowered slightly. The breaking strength changed slightly, and the breaking elongation rate decreased 50 percent. The dyeing rate is higher than ordinary spandex when used acid dyes, but disperse dye dyeing with almost no change, both as a result, ordinary spandex after modification, good to dyeing, acid dyes so as to achieve the purpose of easy dyeing.By analyzing the property differences of dyeable and normal spandex fibers, the research foundation of modification, dyeing process and dyeing mechanism of spandex was established.Through to the spandex dyeing temperature, dyeing time and dye bath pH and bath ratio and other single factor analysis and orthogonal test with Neutral bordeaux GRL, Neutral swaths of GL and neutral orchid BM 2%(o.w.f.), and the best dyeing process was decided such as: T = 90 ℃, t = 60 min, pH = 4.5 and liquor ratio= 1:30.Under this optimum process, for dyeing dyeable spandex and ordinary spandex quality analysis, the results showed that dyeable spandex color depth,Fastness than ordinary spandex and it is admined by18401-2010 standard. As is portrayed by the increase of the concentration of the dye dyeing K/S value increased with the concentration of dye ascend, from beginning to the magnitude of the larger of the rate,and smaller amplitude gradually, gradually tend to balance. By research on dye permeability, the results showed that the dye permeability of dyeable spandex is higher than ordinary spandex.After the optimal dyeing process, trichromatic acid dyes(neutral bordeaux GRL,neutral swaths of GL and neutral orchid BM) were used to study the dyeing kinetics and thermodynamics of dyeable spandex fiber with acid dyes.In dyeing kinetics aspects: compared with the ordinary spandex, dyeable spandex dyeing with acid dyes,equilibrium adsorption quantity and dyeing rate constant is obvious increased, and on the half dyeing time shortened, and the diffusion coefficient is increased. In dyeing thermodynamics: under the condition of large bath ratio, acid dyes dyeing is easy to dye adsorption isotherm of spandex type and type of adsorption isotherm on ordinary spandex, meet the Langmuir adsorption isotherm + Nernst type. Compared with ordinary spandex, acid dyes dyeing dyeable spandex dyeing affinity, dyeing heat and dyeing entropy increases.