Relationships between birefringence of constituent fibers and properties of thermally bonded nonwovens

Three-dimensional nonwoven fabrics have been produced using a newly developed air-laid web forming and through-air thermal-bonding process directly from commercial PP/polyester (sheath/core) bi-component staple fibers. Following the previous study on the morphology and structure of constituent fibers,, this paper reports the breaking force and abrasion resistance of the fabrics. Results indicate that the relationships between both the breaking strength and abrasion resistance of the samples, and the thermal-bonding process conditions, are similar to each other. The appropriate thermal-bonding temperature and dwell time are critical for achieving fabrics, with high breaking strength and abrasion resistance. Such relationships are inconsistent with those between the tensile, strength of the constituent fiber reflected by the birefringence and the thermal-bonding process conditions. The birefringence of the constituent fiber appears to decrease with increasing thermal-bonding temperature and dwell time. These results provide evidence that both the breaking force and abrasion resistance for the thermally bonded nonwoven fabrics are governed not only by the mechanical properties of constituent fibers, but also by the bonding properties between the fibers. [GRAPHICS] Abrasion mass loss and breaking force of fabric and birefringence of constituent fiber for the thermally bonded nonwoven samples as functions of the dwell time.