Tips | How to improve the color light fastness of textiles?
Color fastness is an important criterion for measuring the quality of textiles. The light fastness is one of the color fastnesses. The light fastness refers to the degree of discoloration of colored textiles under the action of sunlight. The higher the degree of fading, the higher the degree of fading. , indicating that the degree of discoloration is lower.
The factors affecting the light fastness mainly include dye structure, fiber type, dye concentration and the influence of external conditions. The light fastness grades of different fibers are different. For example, the light fastness of indigo on wool is very high. Low, the light fastness of Vlamin Blue Salt B on viscose is much higher than that on cotton. Other external factors include the level of air humidity, temperature and so on. But no matter what kind of factor, there are many additives that can effectively improve the light fastness. How to improve the light fastness of textiles as follows:
1. Dye selection (the most important factor)
①High light fastness of yellow color spectrum: reactive dyes take pyrazoline tungsten and naphthalene trisulfonic acid as the parent structure;
②High light fastness of blue spectrum: reactive dyes take anthraquinone, phthalocyanine and methyl ester as the parent structure;
③The light fastness of red chromatographic reactive dyes is generally low, especially for light colors. Only some azo groups have coordinating hydroxyl groups in two adjacent positions, which form stable chelate rings with copper, which can improve the light fastness. Spend;
④When selecting dyes for color combination, it is necessary to make the light fastness level of each component dye selected to be equal, as long as the light fastness of any one of the components, especially the component with the least amount, cannot reach light color dyeing. The light fastness of the final dyed product cannot meet the standard.
2. Other measures
①Influence of dye floating color, incomplete soaping after dyeing, unfixed dyes and hydrolyzed dyes remaining on the cloth will also affect the light fastness of dyed products, and their light fastness is significantly lower than that of fixed reactive dyes. The more thorough the soaping, the better the light fastness;
②The application of cationic low molecular weight or polyamine condensation resin fixing agent and cationic softener to the finishing of the fabric will obviously reduce the light fastness of the dyed product. Therefore, when choosing fixatives and softeners, it is necessary to pay attention to their influence on the light fastness of dyed objects;
③Ultraviolet absorbers are often used in light-colored dyeings to improve light fastness recently, but they must be used in a large amount to have some effect, which not only increases the cost, but also causes fabric yellowing and strong damage, so it is not a good measure.