The Study Of MVS Spinning For Polyester/Viscose Blended Yarn And The Influence Of Paramenters On Yarn Properties And Structure

Air-jet vortex spinning (MVS) is a new kind of spinning method developed from air-jet spinning (MJS), which utilizes high-speed airflow produced by nozzles to finish the twisting and wrapping of yarn. It has prominent advantages such as:fine-quality, short process, high yield and high degree of automation. Air-jet vortex spinning yarn has the structure similar to that of ring yarn, but MVS yarn has less hairiness, good resistance to pilling and better moisture absorption and release. However, many enterprises found that the MVS polyester yarn usually has significant irregularity in twists, and more weak rings, which lead to higher irregularity in strength.On the base of that, following studies were carried out:(1) Properties of polyester and viscose fiber were tested, and it was found that the oil content, friction properties and stiffness of polyester fiber are bigger than those of viscose fiber, which leads to low spinning ability of polyester in MVS spinning, therefore, the yarn quality is poor.(2) The single factor and orthogonal experiments were designed to optimize the spinning parameters of pure polyester yarn. The optimized parameters were 0.6MPa of the nozzle pressure, 0.5mm of the distance from needle to spindle tube, and spinning speed for 170 m/min. Polyester and viscose fibers were used to produce blended vortex spun yarns, and it was found that along with the increase of polyester fiber ratio, the yarn breaking strength increased, unevenness of strength became poor and yarn hairiness was increased. Other experiments were also designed to study the effect of the blend ratio on the vortex yarn properties, and optimized the parameters.(3) The structure of air-jet vortex spinning yarn was tested and analyzed by microscope photographs. It can be derived that along with the increase of the nozzle pressure, the number of wrapped fibers and the angle of wrapping was increased, which lead to strength improved. With the increase of the distance from needle to spindle tube, the number of wrapped fibers and the angle of wrapping were significantly reduced, which cause the decrease of strength.(4) In order to determine the nozzle's important parameters, a lot of theory analysis and experimental exploration were carried out. Guidance needle height, the diameter of the guiding needle, spiral angle of guidance body(y); jet orifices angle, the diameter and number of jet orifices in vortex tube; The inner diameter of the front of cone body; the internal structure of the doffing tube, and jet orifices angle, the diameter and number of jet orifices in doffing tube were all studied in order to make the nozzle realize spinning.