Spandex, also referred to as Lycra or Elastane, is a synthetic material primarily made of polyurethane polymer. Spandex is not the same as latex, and may be used by people who are allergic to latex.
Introduced in 1958, Spandex threads are lightweight and durable, with greater elasticity than conventional elastic, and were first developed as a replacement for rubber. Spandex became popular for certain types of clothing because it does not deteriorate from oxidation and is not damaged by perspiration, body oils, lotions or detergents. Spandex used in clothing always contains a minimum of 85 percent polyurethane polymer. The remaining chemicals are usually TDI, or Toluene-2, 4-diisocyanate and MDI, or Methylene bisphenyl-4, 4-diisocyanate.