Three Dimensional Structures from Nonwovens

Abstract

The purpose of this research was to assess molding or thermoforming nonwoven webs into a three-dimensional fiber network without the use of resin or binders via the SpaceNet Formed Fiber System ®. We define this network as a deep-draw structure with projections and/or depressions rising from an initial plane, providing a grid-domed structure. The research is comprised of three experimental components: the first concerned with moldability of nonwovens on the SpaceNet System. The second component comprised an evaluation of the effect process parameters on substrate deformation, and the third concerned with an investigation the effect of mold geometry on compressive properties.

Concerning the moldability of nonwovens, eight-nonwoven webs (six spunbond, two hydroentangled) were processed using the SpaceNet formed fiber system. Nonwovens comprised of a uniform fiber orientation and isotropic mechanical properties were found to process more efficiently in the SpaceNet system. Given this conclusion, spunbond nonwovens were selected for the remainder of the research described herein.

Different mold geometries were used to make three-dimensional structures from spunbond nonwovens and their respective compressive properties were evaluated. It was observed that decreases in pin diameter increased the compressive stress in all samples produced. It was also found that compressive resilience is not necessarily associated with changes in mold geometry but rather inherent fabric properties i.e. stiffness and level of bonding.

The effect of preheating and temperature on formed product dimensions was also evaluated. A split-plot factorial design was used and it was determined that temperature alone influences maximum deformation. Preheating (residence time) was observed to be insignificant including all interactions.