Spandex-coated yarn is an elastic thread with spandex as the core, which is made of filament or staple fiber spirally wrapped with stretched spandex. So, what is the main process of spandex covered yarn?
What is the main process of spandex covered yarn?
1. In the spinning process, spandex elasticity is an important process parameter, which affects the elasticity of the core and fabric, as well as the strength, uniformity and creep of the core. The pre-draft ratio of spandex is too small to give full play to the advantages of elastic fabrics. When the pre-draft is too high, spinning is difficult, it is easy to cause breakage, and the product quality will decrease accordingly. In addition, the percentage of spandex also affects the elasticity of the covering, the higher the content, the better the elasticity. When the size of the spandex yarn is constant, the percentage of the spandex yarn decreases with the increase of the draft ratio, that is, the pre-draft ratio of the spandex yarn is inversely proportional to the percentage of the spandex yarn.
2. The elongation of the air coating increases with the increase of the pre-draft ratio of the spandex. After the draft reaches a certain value, the stretchability of the spandex makes the coating curl. Properly increasing the wholesale Nylon Spandex Swimwear Fabrics Material suppliers pre-draft ratio can reduce the percentage of spandex and improve the wrapping curl. However, when the draft is too large, the deformation amplitude of spandex is close to the critical value of deformation, which can reduce the strength and elongation of the coating, but it is beneficial to the evenness of the coating.
3. Under the action of constant drawing force, the phenomenon that the shape changes with time is called creep. When the spandex is pre-stretched by 3.5 times, the creep resistance of the conventional coating is better. It is necessary to adjust the style of the downstream fabric according to the application.
4. In addition to the requirement of the draft ratio of spandex for air coating, another important process parameter of mechanical coating is twist, which affects the quality, elongation and evenness of the thread. The cohesion force between the covering and the spandex wire can be improved, so that the strength of the covering wire can be improved. The twist is too low, the coating is loose, the coating effect is affected, and the core wire is exposed. So the mechanical coating is higher. Too high, the fabric feels hard, and the drape is poor. Generally, it should be adjusted according to the change of thread denier and the different requirements of fabric style. For example, the N40D 20D package is around 600, while the N70D 40D or T150D 40D package is around 480. The elongation of the bag is also mainly determined by the properties of the spandex core. If it is too large, the outer coating is too tight, the elastic effect of spandex cannot be fully exerted, and the elongation rate decreases. As the twist increases, the uniformity of the yarn increases. Too small and the coating is loose. During the spinning process, due to friction and other reasons, it can move slightly along the axial direction of the thread, so the evenness of the evenness can be deteriorated. Spandex covered yarn is an elastic yarn formed by using spandex yarn as the core and covering the stretched spandex yarn with filament or short fiber yarn in a spiral manner.
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