Behaviour of Stretch Denim Fabric under Tensile Load

Abstract

The effect of different types of elastane weft yarn with different levels of elastane content on the tensile properties of the stretch denim fabric has been studied. The wear comfort of stretch denim fabric depends on the tensile load developed at lower extension levels generated by the movement of the body, while the durability of the fabric can be assessed by its ultimate tensile properties. Three types of elastane yarn i.e. cotton staple core spun, polyester staple core spun and polyester multifilament air covered yarn with elastane as core are used as weft to produce the stretch denim fabric samples. These yarns were further produced having different levels of elastane content. It is observed that for the same level of elastane content, the type of yarn structure and composition has a significant effect on the tensile properties of the fabric. In general, the tensile load developed at lower extension level decreases as the elastane content increases thus improving the wear comfort of the stretch denim fabric. The fabric with polyester staple core spun and polyester multifilament air covered elastane yarn as weft showed better wear comfort as compared to the fabric having cotton staple core-spun elastane yarn as weft. As the elastane content in the fabric is increased, it is found that the improvement in wear comfort is higher during the initial increase in elastane level. Generally, the breaking strength of the stretch denim fabrics decreases as the elastane content increases. There is no such drop in breaking strength of the fabric with polyester multifilament air covered elastane yarn with an increasing level of elastane content. The breaking elongation of all the fabric samples with different types of elastane weft yarn increases as the elastane content increases. For the same level of elastane content, breaking strength and elongation of the fabric having polyester multifilament air covered elastane yarn was highest.