What is washing fastness？

The washing fastness of fabrics includes two aspects: fade fastness and stain fastness. Generally, the worse the fading fastness of textiles, the worse the staining fastness.

When testing the staining fastness of a certain textile, the staining condition of the fiber can be determined by checking the staining condition of the fiber to the six commonly used textile fibers (the six commonly used textile fibers usually include polyester, nylon, cotton , Acetate, Wool or Silk, Acrylic. The color fastness test of the six fibers is generally done by a qualified independent professional inspection company. Such a test is relatively objective and fair.) For cellulose fiber products In other words, the washing fastness of reactive dyes is better than that of direct dyes. The dyeing process of insoluble azo dyes, vat dyes and sulfur dyes is more complicated than reactive dyes and direct dyes, so the washing fastness of the latter three dyes is better. Therefore, to improve the washing fastness of cellulose fiber products, it is not only necessary to choose the correct dye, but also to choose the correct dyeing process. Properly strengthening washing, strengthening fixation and soaping can significantly improve washing fastness.

For the deep color of polyester fiber, as long as it is fully restored and cleaned, the washing fastness of the fabric after dyeing can meet customer requirements. However, because polyester fabrics are mostly softened and finished by padding cationic silicone softeners to improve the feel of the fabric, at the same time, the anionic dispersant in disperse dyes may diffuse on the surface of the fiber due to the heat migration of the dye when the polyester fabric is set at a high temperature. The washing fastness of polyester fabrics with dense color and lustre may be unqualified after setting. This requires that not only the sublimation fastness of disperse dyes, but also the heat migration resistance of disperse dyes should be considered when choosing disperse dyes. There are many ways to test the washing fastness. According to different testing standards, testing the washing fastness of textiles will draw different conclusions.

When foreign customers propose specific washing fastness indicators, if they can propose specific testing standards, it will be conducive to smooth communication between the two parties. Although strengthening washing and post-treatment can improve the washing fastness of fabrics, it will also increase the emission reduction of dyeing plants. Finding some high-efficiency detergents, rationally formulating dyeing and finishing processes, and strengthening short-process process research can not only improve production efficiency, but also contribute to energy conservation and emission reduction.