Views: 1000 Author: Site Editor Publish Time: 2021-03-03 Origin: Site
The pre-treatment of cotton fabrics usually needs to be treated with a higher concentration of alkali to remove fabric impurities (especially with a larger amount of mercerizing alkali). It is not easy to wash the alkali into the fiber. When dyeing (reactive vat dyes), alkali should also be added. The cloth surface may be alkaline during finishing.
On fabrics containing short fibers (cotton cloth, T/R cloth, velvet), it is inevitable that some short fibers will fall off during the processing. Silicone oil produces cohesion, and as the finishing liquid goes up to the rollers, it bonds with the silicone oil that has been squeezed and demulsified to form sticky rollers or silicon spots.
Most of the dyes and brighteners used in cotton are anionic, while the whitening of cotton is basically done on the setting machine. In addition, when the color of the dyed fabric is not correct, the color needs to be fine-tuned. The color correction is usually added with a small amount of dye or paint when applying the soft finishing agent. The factory generally uses ordinary silicone oil (weak cation) to cause anion and cation charge attraction reaction, causing agglomeration and sticking to the roller. , And the softness of the anionic silicone oil does not meet the requirements, causing confusion in the factory. The charge uniformity must be considered during processing.
The cloth dyed by the long cotton car must be dried in a drying cylinder, and then packed in a large package or stacked in a cloth box. If it is not sufficiently cooled, especially the cloth in a large package, the surface temperature of the fabric may be higher when it is soft. This causes the temperature of the working fluid in the rolling groove to rise (especially in summer), sometimes reaching above 60°C, and when the heat resistance of ordinary silicone oil is not good, it can also cause sticking of the roll.
It is better that the temperature in the rolling groove does not exceed 40 ℃.
When the factory is making some thin fabrics, the speed of shaping is very fast, sometimes reaching a speed of 60 m/min. Due to the poor permeability of ordinary silicone oil, the silicone oil flows back on the roller, which causes the roller to stick. Pay attention to changing the working fluid in the rolling trough and rub the roll frequently.
In many factories, when dipping and softening, ordinary silicone oil will stick to the cylinder wall. Over time, some black oil spots will form on the cylinder wall, which will form silicone oil spots on the cloth surface.
A long time of shutdown during operation causes the fabric to stay yellow and the amino hydrogen of the amino silicone oil is easily oxidized by air to form a chromophore, which turns yellow.