Spandex, Lycra, or elastane is a synthetic fiber known for its exceptional elasticity. It is a polyether-polyurea copolymer that was invented in 1958 by chemist Joseph Shivers at DuPont.
The name "spandex", which is an anagram of the word "expands", is the preferred name in North America. In continental Europe, it is referred to by variants of "elastane", including élasthanne (France), Elastan (Germany, Sweden), elastano (Spain), elastam (Italy), and elastaan (Netherlands); and in the UK, Ireland, Portugal, Spain, Latin America, Australia, and New Zealand, it is primarily known as "Lycra".
Brand names for spandex include Lycra (made by The Lycra Company, previously a division of DuPont Textiles and Interiors), Elaspan (The Lycra Company), Acepora (Taekwang Group), Creora (Hyosung), INVIYA (Indorama Corporation), ROICA and Dorlastan (Asahi Kasei), Linel (Fillattice), and ESPA (Toyobo).
Unlike many other synthetic fibers, spandex cannot be melt-processed because the polymer degrades upon melting. Spandex fibers are produced by several spinning technologies. Typically, a concentrated solution of the polymer is drawn through spinnerets at temperatures where the solvent evaporates.
Spandex is mainly composed of a polyurea derived from the reaction of a diol and a diisocyanate. Two classes of spandex are defined by the "macrodiols". One class of macrodiols is the oligomer produced from tetrahydrofuran (i.e. polytetrahydrofuran). Another class of diols, the so-called ester diols, are oligomers derived from condensation of adipic acid and glycols. Spandex produced from the ester diols is more resilent photochemically and to chlorinated waters. Almost always, the diisocyanate is methylenebis(phenyl isocyanate). The key linking reaction is formation or the urea (aka urethane):
The polyurea is usually treated with various diamines, which function as chain extenders.
The exceptional elasticity of spandex fibers increases the clothing's pressure comfort, enhancing the ease of body movements.