Spandex is short for polyurethane fiber. It is a kind of synthetic fiber.The product names are Lycra (USA, UK, Netherlands, Canada, Brazil), Neolon (Japan), Dorlastan (Germany), etc.First by the German Bayer company research success in 1937, the United States dupont in 1959 began to industrialized production, already the spandex industry Koch industries, sold to the United States, a total capacity of up to about 100000 tons.At present, the total global production capacity of spandex is about 600,000 tons, while the production capacity of Korean xiaoxing company is nearly 120,000 tons, making it the first in the world.China's first polyurethane enterprise is yantai polyurethane factory, started production in 1989.The Chinese mainland has a production capacity of about 350,000 tons and is the world's largest producer of spandex.
Spandex with a total of two varieties, one kind is by aromatic double isocyanate and Mosaic copolymer containing hydroxyl polyester chain segment (hereinafter referred to as polyester spandex), another kind is by aromatic pair of isocyanate and polyether segment containing hydroxyl Mosaic copolymer (hereinafter referred to as polyether type of polyurethane).Spandex fiber and elastic polyolefin fiber and elastic composite fiber are collectively called elastic fiber.
Synthetic fiber with high breaking elongation (over 400%), low modulus and high elastic recovery rate.The name of the Chinese commodity of multi - block polyurethane fiber.Also called elastic fiber.Spandex has high elongation (500% ~ 700%), low elastic modulus (200% elongation, 0.04 ~ 0.12 g/Dan), and high elastic recovery rate (200% elongation, 95% ~ 99%).In addition to high strength, other physical and mechanical properties are very similar to natural latex silk.It is more resistant than latex silk chemical degradation, with medium heat stability, softening temperature about 200 ℃ or more.Most dyes and finishes used in synthetic fibers and natural fibers are also suitable for dyeing and finishing of spandex.Spandex is resistant to perspiration, sea water and various dry cleaning agents and most sunscreen oils.Long-term exposure to sunlight or in chlorine bleach will also fade, but the degree of decline varies with the type of spandex, a big difference.
With such high elastic spandex fiber so because of its high polymer chain is made up of low melting point, the amorphous "soft" chain segments for maternal and embedded in one of the high melting point and crystallization of "hard" segment.A certain network structure is formed between the molecular chains of the flexible chain segment with a certain crosslink. Due to the small interaction force between the molecular chains, it can freely expand and expand, resulting in large elongation performance.The binding force of rigid chain is large, so the chain will not extend indefinitely, resulting in high resilience.The cross section of the radon filament is mostly dog-bone shaped, and some of the filament has smooth or serrated surface.Fracture strength was the lowest among all textile fibers, only 0.44 ~ 0.88CN/dtex (polyether strength was higher than polyester strength).The hygroscopic range is small, generally 0.3-1.2% (the hygroscopic rate of the filaments is slightly higher than that of single filaments).Differ from that of heat resistance depends on the variety, most of the fiber in 90 ~ 150 ℃ within a short time to deposit, the fiber will not damage, safety pressing temperature is below 150 ℃, can heat disturbance and wet cleaning.Dyeing performance is better, can be dyed various colors, dye affinity of the fibers is strong, can adapt to most of the varieties of dyes, and has good chemical resistance, resistance to most acid, chemicals, organic solvents, laundry detergent and bleach, and resistant to sunlight and wind and snow, but not oxide resistance, easy to reduce fiber turn yellow and powerful.
Generally, spandex is not used alone, but mixed into the fabric in small amounts.This fiber has the performance of rubber and fiber properties, most used in core-spun yarn with spandex core yarn, referred to as elastic core-spun yarn, the main characteristics of this kind of yarn, it is can obtain good handle and appearance, with outside of natural fiber, fiber hygroscopicity good;Second, only 1-10% spandex filament can produce high quality elastic yarn;Third, the control range of elastic percentage is from 10% to 20%. Different elastic values can be selected according to the purpose of the product.In spinning to 25 ~ 2500 denier silk of the different thickness, so widely used to make elastic woven fabrics, such as socks, furniture cover mouth, ski clothes, sportswear, medical fabrics, take classes, military equipment, such as the elastic part of the suit.As people put forward new demands on fabrics, such as light weight, comfortable wearing, soft texture, etc.It can also be used for the combination of polyurethane nude silk and polyurethane with other fibers.