In production, it is often encountered that polyester or polyester-containing fabrics are dyed out of the cloth, the color of the cloth is normal, and after the next process, the color does not match, that is, the color is changed or the spots are spotted, the stripes are colored, and the fastness is reduced. Such problems can be repaired if they are re-repaired. However, the re-repairs can hardly meet the requirements, which will bring certain impact and loss to the normal production, delivery, quality and efficiency of the factory. What is the reason for this?
It turned out to be the fault of thermal migration of polyester. What is the thermal migration of polyester?
Thermal mobility is a common property of disperse dyes, which refers to the effect of dry or humid air on the finishing of high-temperature finishing. Part of the dye migrates from the inside of the fiber to the surface of the fiber through the fiber capillary, causing the accumulation of dye on the surface of the fiber. Redistribution, the presence of the additives and their surfactants, including the residue on the cloth, will aggravate its production.
Since this kind of thermal migration is mainly related to the structure of the dye itself, and the disperse dyes of different structures have different thermal migration characteristics, and the differences between them are also large, so especially when using silicone oil, When it is antistatic, it contains a certain amount of surfactant, and when these additives have uneven adsorption on the cloth surface, including uneven PH on the cloth surface, the so-called so-called blooms, color changes, and decreased fastness such as friction will occur. , Washing, staining and other problems, this phenomenon is often manifested as one or more of the coexistence, which brings insurmountable hidden dangers and harm to the quality of dyeing.
Solution:
1. Firstly, it is necessary to choose disperse dyes with small thermal migration and similarity. Because of the large molecular weight of these dye structures and their affinity with polyester fibers, it is difficult to migrate from the inside of the fiber to the surface. Such as the commonly used LXF type, XF type, XF / SF type and MS series on the market have good heat migration fastness.
2.Select the same type or high-temperature type dye as much as possible for the color-matching dyes, because different types of dyes have different thermal migration ratios and different sublimation fastnesses, and high-temperature type sublimation fastnesses are high, The degree of sublimation is not consistent with the sublimation fastness, but high-temperature dyes have less sublimation under higher temperature setting, and the stability of the corresponding shade is also good.
3. Post-finishing adopts a gentler process, the deeper the color, the more the migration amount of the dye, the higher the temperature, the greater the impact on the migration. Under the condition of ensuring the setting effect, depending on the variety, you can choose 150 ℃ or lower The temperature. In order to avoid or reduce the migration of dyes, it is recommended that such varieties can be fixed at a predetermined size using high temperature.
4.Select the finishing softener, try to use hydrophilic silicone oil or self-emulsifying block silicone oil without emulsifier, and this kind of silicone oil has good stability, low color and yellowing, and it can play a better role in dye migration. Good preventive effect.
5.Enhance the reduction cleaning after dyeing, especially the dark color.The floating color must be fully washed to ensure its own fastness.At the same time, the acid cleaning should be used as much as possible. If the alkaline insurance powder process is used, it must be neutralized. Dyes are more sensitive to pH, and some will turn blue to purple after finishing at high temperature when pH> 6, and this color change is irreversible, and even cannot be repaired.
As long as the above measures and reasonable pre-treatment and dyeing processes are used in the production process, it is believed that a series of quality problems such as post-finishing and color setting, color change, and decrease in fastness will definitely be controlled within our requirements.
