Mechanism of crease generation
1. Cotton knitting boiling and dyeing processing is generally carried out in the overflow tank, the whole processing process of the fabric is kept in a rope-like state, the fiber is constantly bent and deformed in the dyeing machine, the original hydrogen bond is constantly destroyed, the new hydrogen bond is constantly formed, sometimes the newly formed hydrogen bond can not be completely recovered, so the surface of the fabric forms chicken paw prints, dead creases.
2. In the single-sided fabric structure, the tension of the two-sided yarn is asymmetrical, and it is difficult for the fabric to recover after a long time of unidirectional wrinkles, so it is more likely to have creases in various structures, especially in the fabric with less or larger gram weight. The crease is also very related to the yarn count and twist, the smaller the yarn count, the higher the twist, the greater the reverse untwisting of the yarn, and the more prone to crease problems.
The main process step in the formation of creases is boiling and bleaching
1. The general dyeing and finishing process is: cloth preparation→ seam head→ falling into the cylinder boiling and bleaching→ dyeing→ soaping→ color fixing→ soft → out of the tank→ dehydration→ shock wave machine or hair dryer dry cloth, generally more people think that the formation of creases is mainly in the dyeing vat, and our engineers have rigorously experimented to demonstrate: in fact, most of the cotton knitting has formed creases in the boiling and bleaching stage, but it is not easy to observe before dyeing.
2. The following types of fabrics and equipment are susceptible to creases during the boiling and bleaching stage:
Fabric reason: single-sided cotton fabrics with less or larger weight (such as < 150g or >300g), especially cotton frame (with spandex) fabrics;
Equipment reasons: Compared with the L-type relief cylinder, the J-type relief cylinder is more prone to creases due to its strong tensile force; The air flow cylinder is less prone to creases, because the fabric is fully blown open by high-pressure gas at the nozzle, and the fibers get "rest" from the tense state, which is conducive to the elimination of internal stress to reduce the crease problem;
Process reasons: fabrics that have not undergone predetermined shapes are more likely to have crease problems; The fabric is shaped at high temperatures, which improves fiber proximity and orientation, and the fiber morphology is fixed, reducing the chance of changes in the dye vat and helping to reduce creases.
