No, I always feel that the buttocks of the jeans I have only worn a few times recently are fluffy. I think I should be greedy for cheap. I bought a product with poor wear resistance, which is probably pilling. I washed these trousers two days ago, and took a closer look at the fabric of the buttocks while drying them. There were a lot of white hairs on them, which did not look like simple fluffing and pilling, so I pulled the white hairs with my hands. It turned out that the spandex yarn in the fabric was broken, and the broken spandex yarn shrank after washing, so the broken end was exposed.
After the spandex yarn in clothing is broken, it will elastically shrink under the action of daily friction, and the spandex yarn will expose the yarn. It will loosen and bulge out, and the clothes will not be able to wear. In the past, I also encountered the problem of broken spandex from customers at work. At that time, most people thought that the spandex was broken because of the improper selection of needles when sewing clothes. Of course I have to carefully analyze the cause of this problem.
We know that the reason why fabrics are elastic is because of the use of elastic yarns for weaving. Therefore, the reason for the breakage of spandex filaments in fabrics must first be found in the spinning process. More than 20 years ago, in order to develop elastic fabrics, I was fortunate to participate in the development of elastic yarns, so I have a good understanding of the production of elastic yarns. There are three production processes of elastic yarn, one is the core-spun process, the other is the wrapping process, and the other is the simple twisting process.
Another important process parameter to consider in the processing of elastic yarn is the fineness and draft ratio of spandex. When the spandex is wrapped into the yarn, it is not twisted into the yarn in a natural state, but is twisted into the yarn under a certain elongation state, otherwise the spandex yarn cannot be elastic. The thicker the spandex and the greater the draft ratio during spinning, the higher the elasticity of the spun yarn, but the greater the draft ratio, the greater the tension of the spandex yarn in the yarn, and the greater the tension in the subsequent processing. It is easy to fatigue and break, so it is necessary to design a reasonable spandex fineness and draft ratio when spinning. The spandex fineness generally depends on the fineness of the yarn being spun. The thicker the yarn, the thicker the spandex that needs to be used. 30D Spandex yarn is widely used in yarns of conventional fineness, and the draft ratio of spandex is generally about 250%-300%, which is more suitable. In order to reduce costs, some enterprises use thinner spandex yarns with a larger draft ratio to spin, so that the amount of spandex yarns is reduced, and the elasticity of the spun yarn is also good, but this The yarn cannot withstand tossing, and it is easy to break in the back.
Elastic fabrics should also pay attention to the protection of spandex yarns during the weaving and dyeing and finishing processes. In the weaving process, in order to ensure that the yarn is straight and not bowed, sufficient tension must be applied to the weft yarn during weft insertion to keep the weft yarn straight, but if the weft insertion tension is too large, it is easy to break the spandex yarn in the yarn. Especially when weaving with an air-jet or water-jet loom, if the pressure of the nozzle is too high, the outer fiber in the yarn will be blown away and the core of the spandex filament will be exposed, which will easily cause the spandex filament to break. When dyeing and finishing elastic fabrics, we must be careful in the selection of additives used. We know that spandex is a polyurethane substance, which is easy to dissolve in organic solvents, and some of the various additives used in the dyeing and finishing process contain organic solvents. If Using such additives containing organic solvents to treat elastic fabrics will easily cause spandex to break due to dissolution.
Also in the process of clothing processing will cause spandex yarn breakage. First of all, in the sewing process, if the sewing needle is unreasonably selected, the spandex yarn in the yarn core will be cut off. Therefore, if the needle bar is strong enough, the needle size should be small, and the needle should use a round needle. Secondly, for the garments to be washed and finished, like the dyeing and finishing process, the washing auxiliaries should also pay attention to the problem of organic solvents; spandex is sensitive to halogen chemicals and is easy to cause degradation, so do not use chlorine for products that need to be rinsed. Bleaching; spandex is also sensitive to PH value, too strong acidity is easy to be brittle and broken, too strong alkalinity is easy to degrade and break, so the pH value adjustment must be appropriate when clothing is washed; spandex is not resistant to high temperature, too high temperature will lose Elasticity, and the temperature should be lowered gently when washing. If the temperature is too fast, the spandex will be brittle and broken.
- Spandex
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