Spandex—or elastane—is a synthetic fiber known for its exceptional elasticity. It is stronger and more durable than rubber, its major non-synthetic competitor. It was invented in 1959 by DuPont chemist Joseph Shivers. When first introduced, it revolutionized many areas of the clothing industry.

"Spandex" is a generic name and not derived from the chemical name of the fiber, as are most manufactured fibers, but an extension of the word expand.Kadolph, Sara J. Textiles. "Spandex" is the preferred name in North America; elsewhere it is referred to as "elastane".Fact: date=August 2008

The most famous brand name associated with spandex is Lycra, a trademark of Invista (formerly part of DuPont). Such is the prominence of the Lycra brand that it has become a genericised trademark in many parts of the world, used to describe any kind of spandex. Invista discourages such use, protecting its trademark vigorously.

Other spandex trademarks include Elaspan (also Invista's), ROICA & Dorlastan (Asahi Kasei) and Linel (Fillattice).

Spandex fiber production

Spandex fibers are produced in four different ways, including melt extrusion, reaction spinning, solution dry spinning, and solution wet spinning. All of these methods include the initial step of reacting monomers to produce a prepolymer. Once the prepolymer is formed, it is reacted further in various ways and drawn out to produce a long fiber. The solution dry spinning method is used to produce over 90% of the world's spandex fibers."How spandex is made" from How Products Are Made

Solution dry spinning

Step 1: The first step is to produce the prepolymer. This is done by mixing a macroglycol with a diisocyanate monomer. The two compounds are mixed together in a reaction vessel to produce a prepolymer. A typical ratio of glycol to diisocyanate is 1:2.

Step 2: The prepolymer is further reacted with an equal amount of diamine. This reaction is known as chain extension reaction. The resulting solution is diluted with a solvent to produce the spinning solution. The solvent helps make the solution thinner and more easily handled, and then it can be pumped into the fiber production cell.

Step 3: The spinning solution is pumped into a cylindrical spinning cell where it is cured and converted into fibers. In this cell, the polymer solution is forced through a metal plate called a spinneret. This causes the solution to be aligned in strands of liquid polymer. As the strands pass through the cell, they are heated in the presence of a nitrogen and solvent gas. This process causes the liquid polymer to react chemically and form solid strands.

Step 4: As the fibers exit the cell, an amount of solid strands are bundled together to produce the desired thickness. Each fiber of spandex is made up of many smaller individual fibers that adhere to one another due to the natural stickiness of their surface.