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.

已经研究了具有不同氨纶含量的不同类型的氨纶纬纱对弹力牛仔布的拉伸性能的影响。弹力牛仔面料的穿着舒适度取决于在身体运动产生的较低拉伸水平下产生的拉伸载荷，而面料的耐用性可以通过其极限拉伸性能来评估。三种弹力纱线即棉短纤包芯纱、涤纶短纤包芯纱和以弹力纤维为芯的涤纶复丝气流包覆纱作为纬线生产弹力牛仔布样品。进一步生产的这些纱线具有不同水平的弹性纤维含量。据观察，对于相同水平的氨纶含量，纱线结构和成分的类型对织物的拉伸性能有显着影响。一般而言，随着弹性纤维含量的增加，在较低拉伸水平下产生的拉伸载荷会降低，从而提高弹力牛仔布的穿着舒适度。与以棉短纤包芯氨纶纱为纬线的织物相比，以涤纶短纤包芯纱和涤纶复丝气流包覆氨纶纱为纬线的织物表现出更好的穿着舒适性。随着织物中弹性纤维含量的增加，发现在弹性纤维含量的初始增加期间，穿着舒适性的改善更高。通常，弹力牛仔布的断裂强度随着弹性纤维含量的增加而降低。随着弹性纤维含量的增加，聚酯复丝空气包覆弹性纤维纱线的织物断裂强度没有这种下降。具有不同类型弹性纬纱的所有织物样品的断裂伸长率随着弹性纤维含量的增加而增加。对于相同水平的弹性纤维含量，具有聚酯复丝空气包覆弹性纤维纱的织物的断裂强度和伸长率最高。