 The Federal Trade Commission's official definition of olefin fiber 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”

Polymerization of propylene and ethylene gases, controlled with special catalysts, creates olefin fibers.Dye is added directly to the polymer before melt spinning is applied.Additives, polymer variations and different process conditions can create a range of characteristics.