The Study On Dye-free Coloration Of Protein Fibers At Low Temperature

With the development of environmental protection consciousness among the entire people, pollution problem which synthetic dyes bring in the process of production and application, has attracted more and more attention in recent years. Under green revolution’s tide, the dyeing and finishing industry tends to develop in the direction of the environmental protection, ecology and low carbon. In view of the current situation, many methods of green ecological dyeing process gradually replace the traditional process, and dye-free coloration technology also arises at the historic moment.According to the theory of the tryptophan reacted with the benzaldehyde derivative, different benzaldehyde derivatives are chemically reacted with the protein fibers under the acid condition in this article, to achieve the coloration purpose. The coloration process is reacted in the protein fiber, it would greatly improve every dyeing fastness. Furthermore, it avoided using the massive dyestuff and reduced the emissions of dyeing waste water. Fenton reagents are used to carry on the pretreated process in this paper to strip off the scales, more advantages for molecules entering fibers, and this would reduce the energy consumption in the finishing process. Different benzaldehyde derivatives (4-hydroxy benzaldehyde and 3,4-dihydroxy benzaldehyde), acids (concentrated nitric acid, hydrobromic acid and hydrochloric acid) and fibers (wool and tussah silk) are chosen as reactant, respectively. They are discussed through a series of experiments that concentration of benzaldehyde derivatives, acid concentration, reacting temperature and reacting time have influence on the coloration of the fiber. Then the treated fibers are carried on the optimized analysis on the color, the breaking strength and the performance.The results show that, along with benzaldehyde derivative and acid changing, the colors of treated fiber are also different, and the concentration play a decisive role on the color depth. In the dye-free coloration technology, the benzaldehyde derivative play the key role on the fabric color finally, the type and position of the groups determine the final show color of fabric. Meanwhile, different acids reacting with the same benzaldehyde derivative, also make the final colors different. In order to further reduce energy consumption, this paper the Fenton reagents are adopted in the pretreatment of wool, to strip off the scales on the surface of wool fibers. It was indicated that, after the pretreatment with Fenton reagent, the wool has little damage, and the molecules have less obstacles to enter the inter of fiber, thus under the same condition it could increase the reaction efficiency of coloration effectively.Compared with the untreated fabrics, the wet rubbing fastness and dry rubbing fastness of the samples after dye-free coloration reaction are increased obviously by 1 level, and other fastness was improved by half level. This illustrated that the surface structure of fiber is not damaged during the treatment, with the breaking strength not being affected. Compared with the traditional dyeing at high temperature, the reacting time of protein fiber with dye-free coloration process is shortened greatly. The dye-free treated fibers have good handle and soft color, showing elegant natural style, which greatly improve performance properties of protein fiber greatly. At the same time, the reaction occurs at low temperature, which helps to reduce the fiber damage, show elegant natural style of wool products and improve the quality of the product. And it has important meaning for saving energy and reducing costs, especially in the energy tense situation, meaning more profoundly.