In order to avoid problems such as dye contamination of the spandex component during disperse dye dyeing or reduction in dye fastness (mainly wet fastness) caused by recontamination of the spandex component caused by thermophoresis migration, thermophoresis is chosen. Disperse dyes with less migration and good wet fastness are extremely important. If you choose high-energy type (S, SF type) dyes with good wet fastness, you must pay attention to the harmony with the dyeing conditions.
What should be paid attention to when formulating the process
The mixing rate of the spandex component in polyester/spandex elastic textiles is generally low (within 10%), and the polyester component accounts for the majority. For this reason, disperse dye high-temperature dyeing process is generally used for dyeing processing.
At this time, in order to reduce the impact of the silicone oil agent used during spandex spinning and prevent the physical properties of the spandex fiber from degrading, gentle temperature treatment must be used, and disperse dyes must be prevented from contaminating the spandex. The components cause the phenomenon of reduced fastness. For this reason, special attention must be paid to the setting of dyeing conditions and the selection of dyes and auxiliaries used. When dyeing polyester/spandex elastic textiles, considering the physical properties of the spandex elastic fiber, it must be processed under mild dyeing temperature, tension and other conditions. Of particular note is the need to use devices capable of low tension processing.
During scouring, it is very important to remove the silicone spinning oil used in spandex elastic fiber spinning, but the silicone oil is difficult to remove under ordinary scouring conditions. It is the cause of dyeing defects such as stains, and must be fully refined. It is recommended to use special spandex degreaser additives!
When dyeing, due to the physical conditions of spandex elastic fiber (to prevent it from becoming brittle), it must be dyed at a lower temperature or in a shorter period of time than pure polyester. The standard dyeing conditions for pure polyester are 130℃x 60 min, and the standard dyeing conditions for polyester/spandex elastic textiles are 120℃x 60 min or 125℃x 30 min, 130℃x 15 min. A dispersion leveling agent that has a good effect on preventing disperse dyes from contaminating the spandex component required during dyeing has been developed.
In order to avoid the reduction in dyeing fastness caused by the contamination of the spandex component by the dye during dyeing with disperse dyes or the recontamination of the spandex component caused by thermal migration (mainly wet Fastness) and other issues, it is extremely important to choose disperse dyes with less thermal migration and good wet fastness. If you choose high-energy type (S, SF type) dyes with good wet fastness, you must pay attention to the harmony with the dyeing conditions. According to the type of dye used and the required dyeing depth, the dyeing conditions are set at 130°C for high-energy dyes and 120°C for medium-energy dyes.
[Recommended dyeing conditions]
Temperature x time: 120℃x 60min or 125℃x 30 min or 130℃x 15 min
Auxiliary: Dispersed leveling agent with the effect of preventing spandex components from being stained
pH: Adjust to 5~ 6
After dyeing, in order to remove the disperse dye stained on the spandex component and the unfixed dye on the surface of the polyester, a reduction cleaning process is required. A detergent with good effect in removing disperse dye contamination required for reduction cleaning has been successfully developed.
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