What is the origin of spandex fiber and its main properties?

There are several forms of spandex elastic fiber yarn?

Spandex elastic fiber and other fibers mixed into elastic yarn, the form of yarn currently has three forms: spandex core-spun yarn, spandex twist-spun yarn and spandex covered yarn. The three forms of yarn have essential differences in processing principle and structural properties. Therefore, its use and weaving performance are also very different. Figure 2-4 shows the structure diagram of the three yarns.

Spandex fiber is a kind of elastic fiber, elastic fiber abroad collectively referred to as Spandex (Spandex), China’s product name is spandex, in fact, spandex is only a large category of elastic fiber. Polyurethane fiber (Polyurethane Fibre) is referred to as PU fiber, there are two varieties, one is made of aromatic bisisocyanate and containing hydroxyl polyester chain segment Mosaic copolymer, referred to as polyester spandex, the other is made of aromatic bisisocyanate and containing hydroxyl polyether chain segment Mosaic copolymer, referred to as polyether spandex. The representative trade name of polyester spandex is Vyrent(Vailen), and the representative trade name of polyether spandex is Lyera (Lecra).

The main properties of spandex fiber are: usually 500% ~ 700% of the elongation, elastic recovery performance is good. Retract 97% at 200% elongation and more than 99% at 50% elongation. The relative density of all kinds of spandex is relatively small, generally 1.20 ~ 1.25, the breaking strength is 4.41 ~ 8.82 cN/tex(0.5 ~ 1.Og/denier), polyester spandex strength is lower, polyether spandex strength is higher. The hygroscopic rate is generally 0.3% to 1.2%, the hygroscopic rate of the compound wire is slightly higher than that of the monofilaments, and the heat resistance is generally not damaged by short-term storage at 95 ~ 150 ° C, and the safe ironing temperature is below 150 ° C. Fibers burn slowly and form a gelatinous residue after burning. Excellent dyeing performance, can dye a variety of colors, strong affinity for dyes. Good acid and alkali resistance, bleaching, no mildew.