In the process of dyeing of high temperature high pressure sample dyeing machine, it is hoped that the dyeing process can be completed in a short period of time and the dye can be fully utilized, and the textile can be dyed evenly without causing deformation or damage of the textile. However, the two tend to be contradictory. In order to obtain satisfactory results in both aspects, it is necessary to control the dyeing process well and adopt appropriate dyeing methods.
Control of initial dyeing rate, transfer dyeing and dyeing rate
The dyeing rate is too slow, and the percentage of dyeing is too low, which will cause economic loss. However, the dyeing rate is too fast and the percentage of dyeing is high, which tends to cause uneven dyeing and impermeability. The dyeing liquid of the high temperature and high pressure dyeing machine is directed from the outer layer of the textile. This is the so-called "transfer" phenomenon.
The time required to transfer a twisted yarn together with a skein of white yarn to a half of the former is called a half leveling time. The dye transfer performance can be measured by the half leveling time. It can be seen from the above that the uneven dyeing due to the initial dyeing rate can be improved or remedied by transfer dyeing. This will extend the dyeing time in the case of dye flow.
The dye transfer performance of dyes in high temperature high pressure sample dyeing machines is related to their adsorption properties. Dyes with good transfer dyeability are easily desorbed. Therefore, if the post-treatment is not carried out, the washing fastness of the dye with high transfer performance is relatively low. The two are contradictory. The diffusion rate of high temperature and high pressure dyeing materials. In most cases, increasing the temperature also reduces the percentage of equilibrium dyeing. Therefore, in order to improve the transfer effect, the dyeing temperature may be increased. For example, from the original 90 ° C to 120 ° C, after a period of transfer, and then gradually reduce the temperature to increase the dye.