Elasthane

Spandex is a chemically produced fiber, which usually consists of polyurethane and polyethylene glycol. Spandex is a block polymer which is formed by polyaddition. These fibers are often blended with cotton fibers in fashion to achieve greater elasticity, stretch and a more comfortable feel. The synthetic fiber is very stretchy, yet offers lasting shape retention. Generally, fabric blends with proportions of elastane are referred to as "stretch".