Studies On The Manufacturing Technique And Properties Of Compound Yarns

Each kind of fiber has certain merits and shortcomings; the blending and interweaving of different fibers can give play to each merit and overcome their shortcomings, which realize their performance complementary and offer the foundation for developing the functional fabrics. In recent years, Sirospun and Sirofil spinning technology appeared in succession for the methods of spinning composite yarn, they realized among woolens, ramie and cotton spinning systems. Their relatively strong development potentiality offered the solid foundation for satisfying this request This paper proposes a kind of new thought of spinning method on the foundations of the technology. On the modified ring spinning, the two roving which were fed into drafting units in the same speed output in different speed to realize one ply of yarn cover to another.The spinning process is influenced by various kinds of factors and forms a dynamic equilibrium. Under the dynamic tension functions the relative motion of the fiber is not the same because of permutation at random of the fiber. In the spinning process equalization point of the yarn is influenced by twist, spinning tension, roving interval, and overfeed ratio. Certain relationship exists among them. The paper firstly investigated single-factor, including the roving interval, the weight of traveler, the twist of the yarn, the speed of spindle, and the overfeed ratio. We have understood the impacts on performance and style of the yarn of five important factors thoroughly. As a result, the yarn properties, such as breaking force, breaking extension, Usters hairiness, index, evenness, and imperfections, abrasion resistance, have been measured and discussed. The reason how the different spinning factor to influence the yarn performance was analyzed. We also have established the theoretical foundation for the actual producing practices.Secondly, the optimization of the composite yam was researched in order to investigate the influences of the spinning factors on the yarn properties, with a central compound rotatable design under five levels. The roving interval, weight of traveler and overfeed ratio which influence the yarn performance mainly are the research object. The optimum parameters are as followed: roving interval, 8mm; weight of traveler, 0.05 gs; overfeed ratio, 8%.The relationship between structure and performances of yarn were discussed. On the circular cross-sectional shape, the wrap yarn tends to be a flat shape, which makes the cross-section approximately circular. On the longitude direction, the two components are twisted in the shape of spiral. They are not blended and can be easily distinguished. Because of the different output speeds of the two strands, the faster one has a larger radius of gyration and tends to be distributed in the wrap and the other one tends to be distributed in the core, then the core/warp structure is formed. We also find that the more the blending ratio of wrap yarn and the more the overfeeding ratio, the higher the coverage. Because of the tight inside and loose outside structure, the breaking force and breaking extension are higher than that of single yarns.In the twisting process a part of hairiness is winded into the inner side, the hairiness is reduced, so the hairiness index of the composite yarns is lower than that of single yarns. After the junction point the two plies of yarn can also remedy the deficiency each other. The two components grip loose fibers, which lead to a tighter combination and abrasion resistance life of the composite yarn.