Dyeing process control of high temperature and high pressure dyeing machine
Dec 27, 2021
When the high-temperature and high-pressure dyeing machine is dyed, fibers, yarns and other fabrics are inevitably subjected to various forces such as stretching, bending, torsion, and compression under the action of the high-temperature and high-pressure dyeing machine. Under humid and hot conditions, some fibers are easily deformed by force. As far as stretching is concerned, under the action of high-temperature and high-pressure dyeing machine, excessive liquid flow pressure will compress the fibers into blocks. The initial tensile modulus of some commonly used synthetic fibers and acetate fibers in the wet state decreases with increasing temperature.
When dyeing, people hope to not only complete the dyeing process and make full use of the dyes in a relatively short time, but also to dye the textile evenly without causing deformation or damage to the textile. But the two are often contradictory. In order to obtain satisfactory results in both aspects, it is necessary to well control the dyeing process and adopt appropriate dyeing methods.
If the dyeing rate is too slow and the dyeing percentage is too low, it will cause economic losses. However, if the dyeing rate is too fast and the dyeing percentage is high, the dyeing will be uneven and impermeable. The dye liquor of the high temperature and high pressure dyeing machine flows from the outer layer of the textile. This is the so-called "migration" phenomenon.
The migration performance of dyes is related to their adsorption performance. Dyes with good migration performance are easy to desorb. Therefore, if no post-treatment is performed, the fastness of dyes with high migration performance to washing will be relatively low. The two are contradictory. The diffusion rate of high temperature and high pressure dyeing machine material. In most cases, increasing the temperature can also reduce the equilibrium dyeing percentage. Therefore, sometimes in order to improve the migration effect, the dyeing temperature can be increased. For example, increase the temperature from the original 90°C to 120°C, after a period of dyeing, gradually lower the temperature to increase the dyeing.
Although the uneven dyeing phenomenon can be remedied to varying degrees by dye transfer, it is more important to try to control the dyeing rate. Through the flow of the dye solution, the fibers in different parts of the textile can be dyed evenly under the same conditions. , Thereby preventing or reducing the occurrence of uneven dyeing.
The dyeing rate varies with the properties of fibers and dyes, and varies with the dyeing process conditions. The dyeing process conditions include dye liquor concentration, temperature, dye liquor flow rate and other dye bath conditions, high temperature and high pressure dyeing machines such as bath ratio, dye liquor pH, salt and other auxiliary agents.