The Study On Biological Treatment Of The Pigments Drawn From The Colored Cotton And Its Application

The natural colored cotton means the cotton naturally with color during growing up (when the cotton boll naturally open , the cotton fibres already have color). The products made with color cotton never dye with the chemical dyestuffs and auxiliary, which helps for realizing the " zero pollution " from fibre to cloth. At present, it is one of the ecological fabrics which are the easilist to pass green passport " ISO1400 " authentication. In addition it meets the need of people to return to the nature and is a good seller. So the natural colored cotton products have wide market prospects.Through proper investigation, the fabric made with colored cotton (especially green cotton ) has a unstable phenomenon of color when using. Therefore a series of experiments are done to draw the pigment in the organic solvent, and to test the stability of the pigment to the light and heat, which aims to find the varying-principle of the pigment under light and heat condition.There are many intergrowth things in the colored cotton fibre such as pectin, wax, etc. It is necessary to get rid of the impurity to improve its hydroscopic property. During the pretreatment, NaOH and Na2CO₃ are commonly used, but they are alkaline materials and would do harm to the color. Being a ecological fabric, the natural colored cotton cloth should be treated ecologically, and the biological enzyme is the ideal pretreatment agent. It only acts on a kind of single materials and will not influence on other materials. In this pretreatment process the four greatest factors are: temperature, enzyme consumption, pH value and time. Through the result of a experiment, finding out the optimum enzyme pretreatment program the optimum scheme not only guarantees the hygroscopicity of colored cotton but also maximumly avoids the influence on the color.The greatest shortcoming of colored cotton is that the color will fade away in the course of using, and a large number of documents say that dealing the colored cotton with metal salt can obviously develop its shine fastness, sweat stain fastness and rub fastness. But the treatment has the disadvantage of changing its original color. Therefore two kinds of metal salt are mixed to firm the color, and the color fastness ofcolored cotton gets much better after the treatment.In order to confirm the phenomenon of pigment's shift and the efficiency of firming, laboratory simulation washing is adopted. The data prove that not only the acid and alkaline of wash water sour can cause the change of color, but also the macromolecules of pigment are shifting during the washing process. And at the same time this test also makes sure that the efficiency of firming with two metal salt mixed is very remarkable.