Design and development of fibrous filter media induced by structural characteristics of needle punched nonwoven

This article discussed the structural changes influenced by punching parameters and their impact on the functional properties of needle punched nonwoven. Three punching parameters i.e., punch density, needle penetration depth and stroke frequency were considered as process variables. Three factors three levels Box Behnken experimental design was used for sample preparation. Newly proposed structural indices were used to evaluate the fibre orientation in X and Y direction of fabric using tracer fibre technique. It was found that measured functional properties of fabrics are well correlated with considered structural indices. The fibre coverage area inferred an increase but coefficient of fibre curliness and anisotropy of inclination angle of fibre observed a decrease, with the increase of punch density, needle penetration depth and stroke frequency. Mean flow pore size followed an initial decrease and then, increase, but filtration efficiency and pressure drop followed an initial increase and then, decrease with the increase of punch density, needle penetration depth and stroke frequency. Finally, process parameters were optimized to achieve a filter media with maximum filtration efficiency and minimum pressure drop.