Covered yarn, also known as wrapping the yarn, is an elastic yarn formed by polyurethane elastic fiber as the core and covered with synthetic fiber filament or yarn in a spiral manner. The covered yarn feels stiffer, the yarn is thicker, and the woven fabric is thicker. The strength of the covered yarn is the strength of the outer filament or yarn, so it is stronger than the core-spun yarn of the same specification.
Covered yarn can be divided into single covered yarn and double covered yarn. Single-covered yarn is a layer of filament or yarn wrapped on the outer layer of polyurethane elastic fiber. Due to the small number of covering turns applied to the core yarn, core exposure may sometimes occur on high-elongation elastic fabrics. It is not suitable for dark-colored products and is mainly used for elastic fabrics such as socks and weft-knitted underwear.
Double-covered yarns are covered with two layers of filaments or yarns on the outer layer of polyurethane elastic fiber, and the wrapping directions of the two layers are opposite. Because the outer fibers are symmetrically wrapped with opposite helix angles, the yarn can be achieved without twisting. The balance of yarn elasticity. The processing cost of double-covered yarn is relatively high, and it is mainly used for elastic fabrics such as leg guards, elastic bands, sock mouths, and pantyhose.
Covered yarn is also a stretch yarn formed by using spandex as the core, and non-elastic filament or short fiber yarn wraps the stretched spandex yarn in a spiral manner. One of the most obvious differences between covered yarns and other elastic yarns is the untwisted degree of core yarns. The degree of entanglement between the core yarn and the outer layer is significantly lower than that of the core yarn and the twisted yarn, so its elasticity is higher than the latter two. There is core exposure under tension.
If there is a significant color difference between the dyeing depth of spandex yarn and the outer fiber, under tension, the homochromatic of the textile will be reduced, which is more obvious for dark products. The strength of the covered yarn is mainly the strength of the outer filament or yarn, so the strength is higher.
