空气网络包覆弹力纱中氨纶丝实际预牵伸倍数测试

为测试与评价空气网络包覆弹力纱的实际弹性,分析了空气网络包覆弹力纱的结构及其拉伸性能特征,提出了采用"力学拉伸曲线前段解析法"测算氨纶丝实际预牵伸倍数的方法;分析了典型无张力拉伸断裂曲线,给出了氨纶丝实际预牵伸倍数的计算方法,并对不同规格的空气网络包覆弹力纱进行了测试与分析。结果表明:采用无预加张力拉伸试验的方法,可测得氨纶丝预牵伸的伸长量;结合拉伸试验试样长度,可计算出氨纶丝的实际预牵伸倍数;氨纶丝实测预牵伸倍数均小于名义预牵伸倍数,二者差异的大小取决于预牵伸倍数以及氨纶丝的线密度。氨纶丝的预牵伸倍数越大,差异越大;氨纶丝的线密度越大,差异越小。

Test of actual pre-draft ratio of spandex filament in air covered elastic yarn

In order to test and evaluate the actual elasticity of the air covered elastic yarn, structure and tensile properties of air covered elastic yarns were analyzed, and the test method of actual pre-draft ratio of spandex by the analytical method of front section of the mechanical tensile curve was proposed. Typical non-pre-tensioning tensile curve was analyzed, and the calculation method of actual pre-draft multiplication of spandex was given. The testing and analysis of the air covered elastic yarns with different specifications were carried out. The results show that the tensile elongation of spandex filament can be measured by non-pre-tensioning tensile test. Combined with the specimen length of tensile testing, the actual pre-draft ratio of spandex filament can be calculated. The measured pre-draft ratios are always less than the nominal pre-draft ratios, and the difference between them depends on the pre-draft ratio and the linear density of spandex filament. The larger the pre-draft ratio of spandex filament is, the larger the difference. The larger the linear density of spandex filament is, the smaller the difference.