5. Spandex: Spandex is a kind of high elastic fiber. It was born in DuPont Company in 1959 and named Lycra (Leica). The elasticity of polyurethane fibers is higher than other fibers. It has large deformation capacity and good elastic recovery. The recovery rate of polyurethane fibers reaches 90% when the elongation is 500%. Spandex can be dyed in various colors. It has smooth handle, low hygroscopicity, lower strength than ordinary fibers and is light and soft. It has good acid resistance, alkali resistance and light resistance. Generally, bare yarn is seldom used directly. It usually takes spandex as core, and imitates core-spun yarn and wrapped yarn with cotton, wool, silk, polyester, nylon, etc. to weave elastic fabric, which makes the fabric soft, comfortable and fit, and stretches freely. It is widely used. As long as the fabric contains a small amount of spandex (3%~5%), it can obviously improve the elastic recovery ability of the fabric.
6. Vinylon: It is less used in clothing and more used in industry. The appearance and handle of the fabric are similar to cotton, and the elasticity of the fabric is not as good as polyester and other synthetic fibers. The fabric is easy to wrinkle and has poor dyeing performance. However, its moisture content is better than other synthetic fibers, its specific gravity and thermal conductivity are smaller, its wear is light and warm, its strength and wear resistance are better, and it has excellent chemical resistance, sunlight resistance, seawater resistance and other properties.