Orientation of Fibers in Needle-Punched Nonwoven Fabrics

This work investigates the influence of fabric and bulk densities of needle-punched nonwovens on the perpendicular orientation of fibers to the fabric surface obtained during needle punching. By using the proposed model with the permeability coefficient and fabric parameters, a coefficient reflecting the number of fibers oriented in the direction of airflow in the nonwoven is calculated. It is established that the coefficient in the model depends on the fabric density, varying among nonwovens having different bulk densities. A model was developed to predict the proportion of fibers oriented in the direction of airflow and, consequently, the permeability coefficient of the nonwovens. It is shown that the model is limited by the fabric and the bulk densities.