| 摘要 |
<p>Nonwoven fabric is formed from a spunbond process by extruding generally ribbon-shaped fibers (126) through slot-shaped orifices (124) of a spinneret (122). The ribbon-shaped fibers are rapidly quenched after extrusion to achieve a substantially uniform molecular orientation throughout a transverse cross section of the fibers, yielding stronger fibers. The rapid quenching results largely from the relatively high aspect ratio (thinness) of the fibers and the relatively large surface area of the fibers, which permits the fibers to quickly cool throughout the transverse cross section. The ribbon-shaped fibers are drawn longitudinally by an aspirator (128) that exerts a generally downward force produced by an air stream that longitudinally stretches and transversely attenuates the ribbon-shaped fibers in such a manner that the transverse cross-sectional shape of the ribbon-shaped fibers enhances the interaction between the air stream and the ribbon-shaped fibers to maximize the downward force. The attenuated ribbon-shaped fibers are deposited onto a web forming surface (134), such as a moving wire screen belt to form a web. The web is then bonded to form the nonwoven fabric.</p> |
