Thesis Details

Thesis Title: The effects of fiber blend level, fiber length, and needlepunch density on the physical characteristics of thermally treated needlepunched nonwoven fabric
Thesis Author: Mary Dever
Abstract: In the needlepunched segment of the automotive market, textile producers have recently begun utilizing an additional thermobonding procedure which increases fiber bonding within the web to enhance the physical characteristics of the fabric such as strength, abrasion resistance, and dimensional stability. However, not much is known of the effect certain variables have on these fabric characteristics and what the optimum combination of variables might be for a given fabric specification. This thesis investigated the interaction of selected variables in an attempt to optimize the physical characteristics of the nonwoven fabric formed by the combined needlepunch / thermobond procedure. To determine the effects of polyethylene binder fiber blend level, needlepunch density and polypropylene fiber length, thirty-six fabric conditions, which encompassed all variable combinations, were produced. These fabrics were then subjected to a finisher needling process held constant for all fabric samples. Following this process the fabrics were thermobonded in a through-air oven where the polyethylene binder fiber was activated. Each fabric condition was tested and values for strength, elongation, stiffness, dimensional stability, and abrasion resistance were recorded. These results were analyzed to determine which independent variables had a significant effect on resulting fabric characteristics. Regression equations, relating fabric characteristics to the independent variables, were then constructed. The following general results were noted: 1. As the amount of binder fiber in the blend was increased: Fabric strength increased to a point and then began to decline. Fabric elongation continued to increase. Fabric stiffness showed a significant increase, until a certain level was reached. Beyond that point the increase in stiffness was negligible. Fabric stretch and set characteristics demonstrated a significant improvement as binder fiber was added, to a point. Beyond that optimum level the change in fabric behavior was negligible. Fabric shrinkage was reduced to zero with the addition of binder fiber. Fiber loss due to abrasion was held to a minimum. 2. As needlepunch density was increased: Fabric strength increased at higher levels of needlepunch density. Fabric stretch and set characteristics also displayed improvement at higher levels of needlepunch density. 3. As polypropylene fiber length was increased: Fabric strength continued to increase. Fabric stretch and set characteristics, in general, displayed an improvement. Based on this study it is recommended that further study be performed to detail the effects that needlepunching with forked needles has on fabric properties.