Nonwoven Fabrics, Spunbonded

Abstract

AbstractSpunbonded fabrics are distinguished from other nonwovens by the integration of fiber spinning, web formation, and bonding during manufacture. Spunbonding is an especially efficient method of manufacturing lightweight fabrics, although the sophisticated manufacturing equipment requires significant capital investment. The thermoplastic polymers, polypropylene, polyester, and polyethylene, provide the material base for most of the fabrics produced. Spinning is accomplished by extruding fibers from either multiple spinnetette banks or a wide rectilinear spinnerette onto a rapidly moving porous belt. Fibers deposited onto the belt form an unbonded web that then passes through a bonder, typically thermal in nature. This process bonds some of the fibers to neighboring fibers, thus providing integrity to the sheet structure. Spunbonded fabrics are produced at widths of 3 m or more in order to facilitate productivity. The high speed manufacture of wide‐width, lightweight fabrics of uniform appearance and properties presents many technical problems. The loss of fiber output from just one of the spinnerettes can cause defects which reduce the usable width of the fabrics. The directionality of the fibers within the fabrics can be controlled during the web‐forming process. This action permits specific physical properties to be engineered into the fabric, although the majority of spunbonded fabrics are, by design, quite isotropic in character. Spunbonded fabrics are used in many applications, including diaper coverstock, interlinings, wipes, furniture construction, geotextiles, carpet backing, mailing envelopes, and filtration. Spunbonded fabrics are routinely used as components in complex structures that utilize their unique physical properties. The enormous growth of spunbonded fabric sales since the 1960s is indicative of their usefulness.