There are many reasons for the formation of white spots during dyeing, such as the water point of the dyeing primer machine and the water point of the reduction steamer. If the water point in these places is whiter, it is produced in the front position and lighter, it is produced in the back position. The water point is relatively round or sprayed up where the height difference of the cloth route is small, and the water point long type is generated where the height difference of the cloth route is large.

Some white spots such as mercerizing mill rolling woven bag strip caused by white spots when dyeing here, if mercerizing mill rolling cotton wool caused by dark spots when dyeing here. Other causes of white spots are wax spots, alkali mud, rotten cotton spots and so on.

Fabric quality treatment

If the quality of the grey cloth is good in production, the dyeing rate is high, the dyeing depth is good, and the cloth surface is smooth and uniform. If the quality of grey cloth is poor, the dyed white star and the stripe of cloth are serious. Therefore, when encountering grey cloth containing dead cotton, it is necessary to strengthen the pre-treatment process, and at the same time ensure the safety and reliability of production, clean the cotton impurities as much as possible, cook the dead cotton thoroughly, and improve the dyeing rate and the quality of dyed cloth products.

Cold pile pretreatment fabric due to energy saving, so now there are many enterprises in the application, but the cold pile removal cotton impurities and slurry effect is poor, the cloth is relatively compact, so it is easy to wrinkle when dyeing, and the guide cloth stick is easy to stain dirty spots, so the dyeing production should add less viscous additives, such as: anti-migration agent, whitening agent NT-2.

Polyester woolen fabric, cotton and other thick fabric treatment

When producing poly-cotton wool fabrics or pure cotton and other thick fabrics, if the cleaning effect of bleaching production is poor, the cotton wool is not clean, some fine cotton wool will stick to the cloth, and it is more difficult to remove after rolling, and white spots will be formed in dyeing. Some white spots dyeing bottom machine is not obvious, but if you rub the cloth backwards by hand, cotton wool will fall down and see a lot of white spots. There are also small cotton wool stuck on the cloth is very difficult to remove, dyeing continuous off the machine is difficult to find, but when the need to add anti-wrinkle, anti-rain agent, crosslinking agent and other viscous additives when the cotton wool glued down and exposed white spots.

Therefore, the white spot caused by cotton can not be underestimated, in the production of wool products, should pay attention to clean the wool at the air duct, exhaust fan, brush roller, to prevent adhesion on the cloth surface through the cloth rolling roller is difficult to wash down. If the wool is still not washed after cleaning on both sides, you can brush it again with the brush roller on the grinding machine, and then the dyed wool will be processed clean.

Poor quality fabric treatment

For fabrics with more cotton impurities and dead cotton, increasing alkali concentration (220g/L) during mercerization can effectively improve the quality of color cloth and reduce white stars and stripes.

The ground fabric must pay attention to the aurora print in the production process after the ground, because once there is an aurora print, white spots will be formed when dyeing, so the rolling car and guide cloth rod can not stick to hard things when the mercerizing alkali washing after the ground, to tour inspection, dyeing found that there are aurora print white spots should be treated first and then dyed.

Polyester cotton wool fabric dyeing (disperse/reactive dye two-bath method) has been encountered, the production of disperse dyeing found that there are white spots did not pay enough attention, until the activity of the dye found that the white spots are very heavy before the idea of treatment. To deal with the abrasive cloth aurora print can only be at the cost of the abrasive cloth effect, the use of higher alkali concentration and mercerization, so that the aurora print outside the cloth hair feel the same as the aurora print, so that the aurora print caused by dyeing white spots no longer appear.