Study On The Pretreatment Processes Of Cotton Fabrics Using Enzymes

The traditional cotton fabric pretreatment is carried out with strong alkalis at a high temperature, which leads to high energy consumption and large pollution emissions, so the traditional pretreatment has seriously hampered the development of finishing and dyeing industry. The environmental-friendly,energy-saving and efficient pretreatment is becoming increasingly important. Enzyme,which is mild, dedicated and efficient, has been concerned in the finishing and dyeing industry for a long time, and the enzyme is widely used in textile pretreatment processing now. But many production practices show that some performances of fabric treated by enzymes are still unsatisfactory when compared with the traditional pretreatment. Therefore, producing more suitable enzymes and optimizing more ideal enzyme pretreatment processes become more and more important.In the thesis, the structure and property of cotton fiber and the working principle of the enzyme are discussed firstly. Then single factor experiments are carried out to explore the results brought by different factors of the enzyme treatment to optimize the processes using desizing enzyme and DM-8654 scouring enzyme respectively.The factors are enzyme concentration, p H, treatment temperature, treatment time, and the types and consumption of salts and surfactants. The desizing process and scouring process are probed and optimized respectively again through the orthogonal method on the base of the investigations aforementioned. Based upon the better optimized enzyme scouring process, the effects of treatment using the mixed enzymes are probed. The stability for all the optimized processes mentioned above is investigated.In the paper, based on the investigations advanced, the one-bath-one-step enzyme treatment process is explored through orthogonal test. The desizing percentage,whiteness, capillary effect, and breaking strength of the fabric treated by six different enzyme treatment processes and conventional treatment processes are discussed to evaluate the merits and demerits of each process synthetically. In order to study the function of the DM-8697 catalase, different cleaning ways are used to clean the bleached fabrics. Four reactive dyes are used to dye the fabric treated by enzymepretreatments and traditional pretreatments respectively to study the influence of different pretreatments at the dyeing properties.The results go as follows : the optimum condition for each enzyme is generally different, and the p H has a large influence. Using different kinds of salt in a certain concentration range has an influence up on the activity of the enzymes, and some can enhance the effect of the enzymes while some can inhibit enzymes; JFC, SDS, SDBS at low concentration can substantially enhance the effect of the enzyme treatment, and the JFC is the most ideal surfactant in these three active agents. Mixing more kinds of enzymes doesn't mean more effective, because the differences in the application conditions of different enzymes will affect the results. The effect can be enhanced when the desizing enzyme and DM-8654 scouring enzyme are applied in the same bath. The enzymes mentioned in all the experiments have a certain stable property, so they can be used in actual production. The two-bath-two-step enzyme pretreatment process performs well, the effect of which is close to the traditional process. When the bleached fabric is treated by using catalase, the consumption of hot water can be reduced significantly, while the whiteness and the dyeing brightness of fabric are improved. When compared with the results of the conventional treatment, the dyeing saturation of the textile treated by the enzymes is inferior, but the levelness property is superior, the strength of the fabric lose lower, and the handle become softer and fluffier.