The soaping process is mainly to remove the dyes that are not bonded with the fiber, hydrolyzed dyes and some additives. Cellulose will swell in water and form a double electron layer with the same charge among fiber, water and floating color. Due to the mutual repulsion of the same charge, the floating color will be separated from the fiber and reduce the adsorption. At the same time, it will exist stably in the state of micelles in the soaping solution through the dispersion and emulsification of soaping agent, so as to remove the floating color and improve the soaping fastness. Non ionic surfactants can provide a good spatial barrier to prevent the re contamination of dyes.
By applying mechanical external force, the floating color on the fiber surface is further removed to achieve the effect of removing floating color and anti contamination 628. The soaping process can be expressed by the following formula: fiber floating color + soaping agent, fiber soaping agent + floating color soaping agent.
Fabrics dyed with reactive dyes must be soaped to remove hydrolytic dyes, additives, dirt, etc. Among them, the process of washing hydrolyzed dyes, auxiliaries and dirt can be carried out in two steps: first, because the surface tension of the soaping agent is less than that of the fabric, the soaping solution first penetrates between the fiber and the dye (auxiliaries and other impurities), weakens the adhesion between the fiber and the floating color, and the solvation separates the dirt and floating color from the fiber surface; second, impurities such as dirt and floating color are eluted into the soaping solution, Surfactants in soaping liquid can provide emulsification, dispersion and solubilization, so that floating color and dirt form micellar state 93 and are stably dispersed in soaping liquid.
There is a dynamic balance between the washed floating color and additives and other impurities. Some floating color additives and other impurities will be deposited on the surface of the fabric again to reduce the color fastness. As the name suggests, anti fouling is to prevent floating color and dirt from being stained and deposited in the light or colorless area of the fabric, reduce the color fastness of the fabric and cause fabric defects. There are a series of complex physicochemical effects in the anti fouling process, such as wetting, infiltration, adsorption, solubilization, emulsification, dispersion, desorption and so on. With the help of mechanical action such as external force, floating color and dirt are separated from the fiber surface and stably dispersed in the soaping solution, and will no longer stick to the fabric.
At present, high molecular polymers with special structures are used to achieve the purpose of anti contamination. There are three main forms of anti fouling: (1) high molecular polymers form a protective film on the surface of dyed fabrics, which makes it difficult to elute hydrolyzed dyes and dirt to achieve the purpose of anti fouling. (2) Through the principle that the binding force between different substances is different, the purpose of anti contamination is achieved. Generally, high molecular polymers with stronger affinity for dye molecules and poor affinity for fiber are selected to achieve the purpose of anti contamination. (3) The high molecular polymer forms a protective film on the surface of the colorless fabric, so that the eluted free dye cannot be combined or adsorbed on the colorless fabric to achieve the purpose of anti contamination.
