An Investigation in Structural Parameters of Needle-Punched Nonwoven Fabrics on Their Thermal Insulation Property

The thermal characteristics of hollow polyester fibers were compared with solid polyester fibers in order to study their processing behavior and performance characteristics. The effects of different processing and structural properties including fiber diameter, bulk density of layer, and surface pressure on layers of needle-punched nonwoven fabrics with hollow fibers on thermal resistance properties were also investigated. The results show that hollow fibers have a higher thermal resistance in comparison with solid ones. This is a consequence of air trapping inside the fibers, higher bulkiness, and higher surface area of hollow fibers. Furthermore, thermal resistance of microfibers is better than those of macrofibers in both hollow and solid fibers. The thermal resistance of nonwoven subjected to this study, have an inverted-U-shaped pattern versus the bulk density of the fabric. The results also showed that thermal resistance of needle-punched nonwoven fabrics can be affected by the range of heater temperature during the test, however considerably can be affected by fabric thickness as a main structural property of nonwoven fabrics.