Polypropylene Spunbond Fibers and Methods for Making Same

摘要

Disclosed herein is a spunbond fiber of visbroken polypropylene having an Mw/Mn of from 3.5 to 7.0, an Mz/Mw of from greater than 2.0 and a melt flow rate (230/2.16) of from 50 to 100 dg/min. Also disclosed is a process for producing spunbond fibers comprising melt blending a polypropylene having a melt flow rate (230/2.16) of from 10 to 30 dg/min with a peroxide visbreaker such that the resulting melt flow rate of the visbroken polypropylene is from 50 to 100 dg/min; melt extruding the visbroken polypropylene through a die block such that filaments of the visbroken polypropylene being produced are exposed to a cabin pressure of from 4500 to 7000 Pa; and forming fibers of from less than 6.0 denier. Nonwoven fabrics and multiple-layer structures can be made from the fibers described herein that are useful for filtering and absorption related articles.