Why is the color fastness of disperse dyes poor?

Disperse dyeing mainly uses high temperature and high pressure when dyeing polyester fibers. Although the disperse dye molecules are small, it cannot guarantee that all the dye molecules enter the fiber during dyeing. Some disperse dyes will adhere to the fiber surface, resulting in poor fastness. It is used to destroy the dye molecules that have not entered the fiber to improve the fastness and improve the color light.

Disperse dye dyeing of polyester fabrics, especially in medium and dark colors, in order to fully remove floating colors and oligomers remaining on the surface of the fabric and improve the fastness of dyeing, it is usually necessary to perform reduction cleaning after dyeing. Blended fabric generally refers to a yarn made of two or more components blended, so this fabric has the advantages of these two components. And by adjusting the component ratio, more characteristics of one of the components can be obtained.

Blending generally refers to staple fiber blending, that is, two fibers of different components are mixed together in the form of staple fibers. For example: polyester-cotton blended fabric, also usually called T/C, CVC.T/R, etc. It is woven with yarn blended with polyester staple fiber and cotton fiber or man-made fiber. Its advantages are: it has the appearance and feel of all-cotton cloth, weakens the chemical fiber luster and chemical fiber feel of polyester cloth, and improves the level.

The color fastness is improved. Because the polyester fabric is colored at high temperature, the color fastness is higher than that of cotton. Therefore, the color fastness of polyester-cotton blended fabric is also improved compared with that of cotton. However, to improve the color fastness of polyester-cotton fabrics, reduction cleaning (the so-called R/C) must be done, and post-treatment after dyeing and dispersion at high temperature. The ideal color fastness can only be achieved after reduction and cleaning.