Modeling of spunbond formation process of polymer nonwovens

Abstract

Spunbond process used in nonwoven manufacturing employs the system which combines fiber-forming and bonding together. A high molecular weight polymer, e.g., PP (polypropylene), can be used as a raw material resulting in fibers of 15–35 μm in diameter formed by the spunbond process. The present work aims at simulations of the spunbond process before the bonding stage with a goal of predicting the resulting nonwoven laydown and its three-dimensional architecture, and potentially in future, the corresponding laydown properties. The quasi-one-dimensional equations of fiber dynamics are used as a key element of the multi-fiber modeling. The air flow field is comprised of a section with one-dimensional flow used for stretching and a subsequent section with three-dimensional axisymmetric flow used for fiber deposition. The fiber motion in air flux shaped by the surrounding attenuator is simulated accounting for polymer melt quenching and solidification. The laydown properties, such as the 3-D structure of the web, mass distribution, elevation distribution and fabric cross-sectional structure, are also predicted using post-processing of the numerical results.