Abstract: The most critical process parameter of the strand production is the twist coefficient, including the single yarn twist coefficient and the strand twist coefficient, which not only directly affects the hand feel, volume density, wear resistance, color absorption, feather and fuzzing and pilling of the strand, but also has a great influence on the strong extension performance of the strand. Understanding the relationship between the strand and the strong extension performance of the yarn plays an important role in ensuring the product quality, developing new varieties and guiding the spinning process.
To reflect the twist coefficient ratio of strand performance, with the polyester coarse yarn and pure cotton coarse yarn as raw materials, we spun 18.5tex polyester single yarn and 29.5tex cotton single yarn by changing the twist coefficient ratio, further spun the single yarn into two strands and three strands of polyester and pure cotton, respectively by reverse twisting, and explored the twist coefficient ratio on the strength and elongation, evenness and fabric property of the corresponding double strands and three strands. 
 In this project, the twist design is opposite to the single yarn. Specifically, Z twist is used for single yarn, with the twist coefficient being 340 twist/10cm, while S twist is adopted for two-strand yarns, with the twist coefficient ratios being the two sides, the middle and the end points of  and 2, namely 0.6,, 1, and 1.5. For three-strand yarns, the twist design opposite to that of single yarn is adopted. Specifically, Z twist is used for single yarn while S twist is adopted for three-strand yarns, with the twist coefficient ratios being the two sides, the middle and the end points of  and , namely 0.7, , 1.2,  and 1.8. The properties of the spun two-strand yarns, three-strand yarns and fabrics thereof are tested and analyzed, which is of great research significance.
The results show that with the increase of the twist coefficient ratio, the two-strand yarn and three-strand yarn of the two materials have two design twist coefficient ratios. The two design twist coefficient ratios of the two-strand yarn are  and , and those of the three-strand yarn are  and . When the twist coefficient ratio of the two-strand yarn and three-strand yarn is  and , respectively, the strength and elongation, yarn unevenness and H value of hairiness are the optimal. Whether it is two-strand yarn or three-strand yarn, the fabric with the second design twist ratio has better tearing and tensile properties than the fabric with the first design twist ratio under the same conditions. We study the effect of changing spinning parameters on yarn properties with different twist ratios, spinning modes and twist coefficients. We then optimize the yarn test results, and then spin the yarn with the last comprehensive performance as the raw material to test the fabric properties, and study the influence of different yarn properties on the fabric properties, which has great research significance for weaving woven fabrics with better performance.

Key words: twist coefficient ratio, double line, tripartite line, strength and elongation, yarn hairiness H-value

摘要： 为综合反映捻系数比对股线及其织物性能的影响，选取涤纶粗纱和纯棉粗纱为原料，采用环锭赛络纺分别纺制18.5 tex涤纶单纱和29.5 tex纯棉单纱，然后对纺制的单纱进行反向加捻，分别纺制涤纶双股线和三股线以及纯棉双股线和三股线，优选纱线进行织造。通过改变捻系数比，在两个最优捻系数比的两边以及中间取值，探究捻系数比对相应的双股线和三股线强伸性、条干及其织物性能影响。结果表明：随着捻系数比的增加，两种原料的双股线和三股线都有两个设计捻系数比。双股线第一第二设计捻系数比分别为、，三股线第一第二设计捻系数比分别为、。两种双股线在捻系数比为时、两种三股线在捻系数比为时，股线的强伸性，条干不匀率，毛羽H值综合性能都很不错。无论是双股线或者三股线，第二设计捻系数比的织物的撕裂性能和强伸性能优于同等条件下第一设计捻系数比的织物。文章解决了三股线与捻度设计的关系，为后面纺纱的过程提供了最佳配置，有利于纺纱效率的提升。

关键词: 捻系数比, 双股线, 三股线, 强伸性, 毛羽H值