Olefin Fibers

Olefin fibers, also called polyolefin fibers, are defined as manufactured fibers in which the fiber-forming substance is a synthetic polymer of at least 85 wt% ethylene, propylene, or other olefin units (1). Several olefin polymers are capable of forming fibers, but only polypropylene [9003-07-0] (PP) and, to a much lesser extent, polyethylene [9002-88-4] (PE) are of practical importance. Olefin polymers are hydrophobic and resistant tomost solvents. These properties impart resistance to staining but cause the polymers to be essentially undyeable in an unmodified form. The first commercial application of olefin fibers was for automobile seat covers in the late 1940s. These fibers, made from low density polyethylene (LDPE) by melt extrusion, were not very successful. They lacked dimensional stability, abrasion resistance, resilience, and light stability. The success of olefin fibers began when high density polyethylene (HDPE) was introduced in the late 1950s (see ETHYLENE POLYMERS, HDPE). Yarns made from this highly crystalline, linear polyethylene have higher tenacity than yarns made from the less crystalline, branched form (LDPE) (see ETHYLENE POLYMERS, LDPE). Markets were developed for HDPE fiber in marine rope where water resistance and buoyancy are important. However, the fibers also possess a low melting point, lack resilience, and have poor light stability. These traits caused the polyethylene fibers to have limited applications. Isotactic polypropylene, based on the stereospecific polymerization catalysts discovered byZiegler andNatta,was introduced commercially in theUnitedStates in 1957. Commercial polypropylene fibers followed in 1961. The first market of significance, contract carpet, was based on a three-ply, crimper-textured yarn. It competed favorably against wool and rayon–wool blends because of its lighter