DEVICES FOR ONLINE ASSESSMENT OF NONWOVENS BASIS WEIGHTS AND STRUCTURES

Two devices for quantifying tile basis weight and fiber orientation di stribution function in nonwoven webs have been developed and studied. The basis weight device measures the attenuation of a light beam by th e fabric. The particular device is implemented, calibrated, and tested at speeds up to 400 m/min. By statistical analysis, this device is ac curate enough to use with fabrics that are three or more times less va riable than current commercial nonwovens. The device for quantifying w eb structure measures the orientation distribution function of a stati c sample by light scattering, and it is sensitive enough to detect sub tle differences in spunbonded webs produced with different filament-di spersing hardware. An anisotropy ratio calculated from measured orient ation distribution functions correlates well with fabric tensile prope rties.