In the textile industry, polyester fiber has become one of the important raw materials widely used due to its excellent physical properties, chemical resistance and good processability. Especially when making polyester yarn, its color performance and color fastness are directly related to the market acceptance and service life of the final product. As the key link to give polyester yarn rich colors, the selection and implementation of the dyeing process have an important influence on color fastness.
Dyeing is the process of combining dyes with the surface or inside of fibers by physical or chemical methods to give fibers or yarns specific colors. For polyester fibers, due to their tight molecular structure and lack of hydrophilic groups, the traditional direct dyeing method has limited effect, so disperse dyes are mostly used for dyeing under high temperature and high pressure conditions. In addition, there are advanced processes such as carrier dyeing, high temperature and high pressure dyeing and supercritical carbon dioxide dyeing. The selection and application of these processes directly affect the dyeing effect and color fastness of polyester yarn.
The influence of dyeing process on color fastness
Dye selection and ratio: The choice of dye is the primary factor affecting color fastness. High-quality disperse dyes have better dye uptake and color fixation, and can form stable chemical bonds inside the fiber, thereby improving color fastness. At the same time, a reasonable dye ratio can also effectively avoid problems such as color flower and color difference, and further improve color uniformity and fastness.
Dyeing temperature and time: The dyeing of polyester fibers needs to be carried out under high temperature conditions to ensure that the dye fully penetrates into the fiber. However, too high a temperature or too long a time may cause excessive decomposition of the dye, which in turn reduces the color fastness. Therefore, precise control of dyeing temperature and time is the key to ensuring color fastness.
Use of auxiliaries: During the dyeing process, adding appropriate amounts of auxiliaries such as dispersants, leveling agents, and color fixers can help improve the dispersibility of dyes, increase dye uptake and color fixation effects, and thus enhance color fastness. However, the selection of auxiliaries and dosage needs to be determined according to the specific process and fiber characteristics, and excessive use may be counterproductive.
Post-treatment process: Post-treatment processes such as washing, soaping, and drying after dyeing also have a significant effect on color fastness. Thorough washing to remove floating colors and unfixed dyes, as well as appropriate drying temperature and time, can effectively improve color fastness.