【섬유 지식】 염색 중에 나타나는 흰 반점?

There are many reasons for the formation of white spots during dyeing. 예컨대, 염색 기본 기계의 물 얼룩, 되돌림 오븐의 물 얼룩. If the water spots are relatively white, they occur at the front position; if they are relatively light, they occur at the rear position. Water spots that are relatively round are produced at places with a smaller height difference in the fabric passing route or by being sprayed; water spots that are in a long strip shape are produced at places with a larger height difference in the fabric passing route.
Some white spots occur when the weaving bag strips are pressed onto the silk finishing machine, causing discoloration in this area and resulting in white spots. If the silk finishing machine is equipped with cotton and wool, it will form dark spots during the dyeing process. Other causes of white spots include wax spots, alkali deposits, and rotten cotton spots.
Quality control of fabric
During production, if the raw fabric quality is good, the dyeing uptake rate will be high, the dyeing depth will be good, and the fabric surface will be smooth, uniform and full. 그렇지만, if the raw fabric quality is poor, the white spots and fabric thread knots will be very serious during dyeing. 그러므로, when dealing with raw fabrics containing a large amount of dead cotton and impurities, the pre-treatment process should be strengthened. While ensuring the safety and reliability of production, efforts should be made to clean up the impurities thoroughly and fully cook the dead cotton to improve the dye uptake rate and the quality of the dyed fabric.
The pre-treatment of fabrics in cold stacking is energy-saving and is now being adopted by many enterprises. 그렇지만, the cold stacking method has poor effectiveness in removing cotton impurities and sizing materials, resulting in a relatively compact fabric. During dyeing, wrinkles are prone to occur, and the guide rods are easily stained and develop stains and color spots. 그러므로, during the dyeing process, less viscous additives such as anti-swelling agents and NT-2 bleaching agent should be added.
Processing of polyester brushed fabric, pure cotton and other thick fabrics
When producing polyester-cotton brushed fabric or thick cotton fabrics, if the bleaching and rinsing process in the production fails to achieve good cleaning results, causing the cotton fibers and wool to not be thoroughly cleaned, some fine cotton fibers will adhere to the fabric surface. After rolling and pressing, it becomes even more difficult to remove them. During dyeing, white spots will form. Some of these white spots are not obvious when the dyeing process is completed. 그렇지만, if you rub the fabric surface in the opposite direction with your hands, the cotton fibers will fall off, and you will see many white spots exposed. There are also some fine cotton fibers that stick to the fabric surface very stubbornly and are difficult to remove. They are not detectable even during continuous dyeing and finishing processes. But when adding viscous auxiliaries such as anti-wrinkle, rainproof, and cross-linking agents during the finishing process, the cotton fibers will be adhered down and the white spots will be exposed.
그러므로, the white spots caused by cotton fibers should not be underestimated. When producing brushed fabric products, it is necessary to frequently clean the air ducts, exhaust fans, and brush rollers of the brushing machine to prevent the cotton fibers from adhering to the fabric surface and being difficult to wash off after passing through the fabric rolling machine. If the cotton fibers still cannot be washed away after cleaning on both sides, you can brush again with the brush roller on the brushing machine, and then the cotton fibers will be properly treated.
Quality-deficient fabric treatment
For fabrics with a high content of cotton impurities and dead cotton, increasing the alkali concentration (220g/L) during the mercerization process can effectively improve the quality of the colored fabric surface, and reduce white spots and thread knots on the fabric.
When processing woolen fabrics after mercerization, special attention must be paid to the formation of aurora marks. Because once aurora marks appear, white spots will form during dyeing. 그러므로, during the mercerization and silk washing processes, the roller and the guide roller must not be contaminated with any hard objects. Regular inspections should be conducted. If aurora marks and white spots are found during dyeing, they should be dealt with first before dyeing can proceed.
During the dyeing process of cotton-polyester textured fabric (using the two-bath method of disperse/active dyes), we encountered a problem. When conducting the disperse dyeing process, we noticed some white spots but did not pay sufficient attention to it. It was not until the reactive dyeing process that we discovered the white spots were very severe, and then we found a way to deal with it. To handle the ultraviolet printing on the textured fabric, we could only do so at the cost of the textured effect of the fabric. We then used a higher alkaline concentration and carried out a re-some process to make the texture effect on the non-ultraviolet-printed areas the same as that on the ultraviolet-printed areas. As a result, the dyeing white spots caused by the ultraviolet printing no longer appeared.