Synthetic fiber with high elongation at break (above 400%), low modulus and high elastic recovery rate. China trade name of multiblock polyurethane fiber. Also called elastic fiber.
Spandex has high elongation (500% ~ 700%), low elastic modulus (200% elongation, 0.04 ~ 0. 12g/ denier) and high elastic recovery (200% elongation, 95% ~ 99%). In addition to high strength, other physical and mechanical properties are very similar to those of natural latex yarn. It is more resistant to chemical degradation than latex wire, with moderate thermal stability and softening temperature above 200℃. Most dyes and finishing agents used for synthetic fibers and natural fibers are also suitable for dyeing and finishing spandex. Spandex is sweat-resistant, seawater-resistant, resistant to all kinds of dry cleaners and most sunscreen oils. Long-term sun exposure or chlorine bleach will also fade, but the degree of fading varies with the type of spandex.
Generally, spandex is not used alone, but a small amount is mixed into the fabric. This kind of fiber has both rubber properties and fiber properties, and is easy to spin yarns with different thicknesses of 25-2500 denier, so it is widely used to make elastic woven fabrics, such as socks, furniture covers, ski clothes, sportswear, medical fabrics, belts, military equipment, elastic parts of spacesuits, etc. As people put forward new requirements for fabrics, such as lightness, comfort and softness, the proportion of low denier spandex fabrics in synthetic fiber fabrics is also increasing.
Spandex spandex fiber (also known as spandex fiber) is a highly elastic synthetic fiber that has developed rapidly in recent years. Underwear made of spandex can stretch freely and is known as "second skin", which is widely used in swimsuits, sportswear, underwear, socks, coats, medical bandages and so on. Spandex was first developed by Bayer Company of Germany in 1930s, and the industrialized production was first realized by DuPont Company of the United States in 1959, and then some European countries and Japan began to produce it one after another. The main producers of spandex in the world are DuPont, Universal Pictures, Bayer, Guang Tai Industrial Company, Toray and Toyo Textile Company. The production capacity of these manufacturers accounts for about 70% of the total production capacity of spandex in the world. In 2000, the world spandex production capacity reached 204,300 tons/year, and in 2000, the output reached113,800 tons/year. It is estimated that the output will reach 2,000 tons in 2000.
Since spandex joined WTO, the world's largest spandex elastic fiber market will be China. The demand for spandex in Chinese mainland has soared, and the apparent consumption of 200/kloc-0 is 35,000 tons. After the implementation of the free trade system in 2005, this market will become even bigger. In the next five years, the average annual growth rate of spandex in China is about 15%. China's huge potential consumer market has always been favored by overseas enterprises. It is estimated that the global spandex production capacity under construction and planned in the near future is about 92,000 tons/year, and the production facilities are mainly distributed in China, Taiwan Province Province of China, China, South Korea and Singapore, and the number of overseas enterprises that seize the spandex market in China is also increasing rapidly.