What to do if white spots appear during dyeing

1. Good quality and bad treatment of fabrics

In production, if the quality of the gray fabric is good, the dyeing rate will be high, the dyeing depth will be good, and the cloth surface will be smooth, uniform and plump; if the quality of the gray fabric is poor, the dyeing white stars and fabric stripes will be serious. Therefore, when encountering gray fabrics containing dead cotton and a lot of impurities, it is necessary to strengthen the pre-treatment process. While ensuring the safety and reliability of production, the cotton impurities should be treated as cleanly as possible, and the dead cotton should be cooked thoroughly to improve the dye uptake rate and the quality of the dyed fabric products.
Many companies are now using cold pile pre-treatment of fabrics because of its energy saving. However, the effect of cold pile on removing cotton impurities and slurry is poor, and the fabric is relatively stiff, so it is easy to wrinkle during dyeing, and the cloth guide roller is easy to get dirty and cause stains. stains, so less viscous additives should be added during dyeing production, such as: anti-migration agent, whitening agent NT-2, etc.
2. Processing of thick fabrics such as polyester brushed fabrics and pure cotton

When producing thick fabrics such as polyester-cotton brushed fabrics or pure cotton, if the rinsing and cleaning effect is poor and the cotton wool is not cleaned properly, some fine cotton wool will stick to the cloth surface, which will be more difficult to remove after rolling and rolling. White spots form. Some dyed white spots are not obvious after using the machine, but if you rub the cloth surface with your hands in reverse, the cotton wool will fall off and many white spots will be exposed. There are also tiny lints stuck to the cloth surface that are very difficult to remove and difficult to detect even after continuous dyeing. However, when it is necessary to add anti-wrinkle, rainproof, cross-linking agents and other viscous additives during tentering, the lint will stick down and be exposed. White spots.
Therefore, the white spots caused by cotton wool should not be underestimated. When producing sanded products, attention should be paid to diligently cleaning the cotton wool in the sanding machine blower, exhaust fan, and bristle roller to prevent it from adhering to the cloth surface and making it difficult to wash off after being rolled by the cloth rolling machine. . If the cotton wool is still not clean after cleaning on both sides, you can brush it again with a bristle roller on the sanding machine, and then the dyed cotton wool will be clean.
3. Treatment of poor quality fabrics

For fabrics with a lot of cotton and dead cotton, increasing the alkali concentration (220g/L) during mercerization can effectively improve the quality of colored fabrics and reduce white stars and fabric flakes. During the production process of sanded fabrics, you must pay attention to aurora marks, because once there are aurora marks, white spots will form during dyeing. Therefore, during mercerization and alkali washing after sanding, hard objects should not be stuck on the pads and cloth guide rollers. Frequent inspections are required. White spots with aurora prints found during dyeing should be treated first and then dyed.