Spandex, scientifically called as polyurethane fiber, is a kind of special fiber with high elasticity and elasticity recovery rate. It is also called as polyurethane elastic fiber. Bayer Corporation of Germany developed Polyurethane fiber first. Dupont Corporation of America was the first to industrialized this fiber in 1959, and commercially, its name is Lycra. Nowadays, there are dozens of spandex manufacturers in more than ten countries, and its yearly output adds up to 325 thousand tons. According to the statistics of UK PCI, so far, the biggest five manufacturers of spandex are in turn INVISTA U.S.A., Hyosung Korea, Taekwang Korea, Yantai spandex China and Tongkook Korea. Spandex polymer belongs to a linear block copolymer, and its molecular structure contains two kinds of segments. One is soft segment to provide excellent retractive power, and the other is hard segment to ensure tensile tenacity of fiber. Due to its special molecular structure, spandex possesses excellent stretchability and retractive power. Spandex can be stretched 5-8 times as long as itself, and its elasticity recovery rate can get 98%. Compared with any other fibers, the elasticity of spandex is the best. Besides, spandex has many good properties, such as fine denier, high tenacity, low density, good dyeability and dye fastness etc, so it is a new type of textile material with superior comprehensive performances.