Study On Microwave Dyeing Of Reactive Dyes

Dyeing and printing industry is a heating process with dyes, chemical auxiliaries and water acting as mediums. In recent years, the new technology with the purposes of water saving, energy saving and consumption reducing has become one of the main researches of clean producing in dyeing and finishing industry and has aroused wide attention. Microwave is an electromagnetic wave of especially short wavelength. It is known that microwave can produce heat and can also promote the chemical reaction. When the microwave acts on the substance, the molecule polarizes, and by absorbing microwave energy, it can change the direction and produce vibration, enhancing collision and rubbing among molecules, so that producing heating effect. To promote reaction by using microwave has many advantages such as short reaction time, high efficiency and less energy and so on.The application of microwave as a high technology in dyeing and finishing industry is less reported at home and abroad. The research on the fixation of cotton pad-dye using microwave heating was once reported in some foreign media. The result shows that some dyes under microwave radiation can fix rapidly on the cotton fabrics. During the printing process of polyester, some researchers try to use microwave to fix dyes in place of drying and steam after printing. By comparison, the uniformity of fixation is better and the depth of color is higher by using microwave and vapor steam together. As reactive dyes combine cotton fiber by covalent bond, and they are famous for their colorfulness, complete chromatogram, easy application, cheap cost and fine color fastness, it is expected that microwave can promote the reaction of reactive dyes.This thesis studies reactive dyeing of cotton fiber with microwave heating and using dip-dye and pad-dye respectively, analyzes the effect of dyeing temperature, processing time, alkali concentration, the dosage of electrolyte, dyes concentration, the dye bath ratio on dye uptake and degree of fixation and compares it with traditional dyeing technology. The result shows that under microwave heating way the best dyeing process of reactive dyeing of cotton fiber is: sodium sulfite 50g/l, sodium carbonate 10g/l the dye bath ratio 1:20, dyeing temperature 60°C and microwave time 20 minutes. During pad-dye process, I analyzed the effect of heating time on dyeing depth and color fastness of cotton fabrics. I can get the conclusion that using microwave heating, microwave could help improve the dyeing process and fixation of color and cotton fabrics have fine color fastness after dyeing.This thesis makes research on the effect of microwave on the graft agent, then the effect of the time of microwave and the concentration of graft agents on the degree of dye-up fixation and surface darkness and tests the color fast properties of the dyed fabric. The results show that with the increasing of the time, the graft effect can be improved and the dye-up take and degree of fixation are enhanced in different degrees. And at the same time, the treated fabric owns excellent color fasten property.This paper also makes research on the heat stabilization and physical performance of fiber through DSC and other methods after it is being dyed by microwave. We get the conclusion that the microwave has improved the tear strength and stretch strength of the fabric, but the flexibility of the fabric and the heat stabilization are not much influenced.