Olefin is a synthetic fiber that was patented in 1954 and was first produced in Italy in 1957 and in 1961 in the U.S. According to the U.S. Federal Trade Commission, olefin is “a manufactured fiber in which the fiber forming substance is any long-chain synthetic polymer composed of at least 85% by weight of ethylene, propylene, or other olefin units.” Textiles made of olefin are polypropylene- or polyethylene-based, with the former by far the more common for clothing use.
Originally used mainly in blends with other fibers, textiles of olefin are now often used for sports and active wear. It is resilient, moisture-wicking, quick-drying and warm yet light in weight.