Study On The Technology And Properties Of The Rotor Spun Composite Yarn

In the last ten years of the 20th century, the technology of blending spinning and composite spinning had been made a great progress, mainly using the methods of ring spinning, Sirospun and Sirofil Spinning. The rotor spinning has become one of the most quickly developed spinning methods through 30 years' development. In recent years, the study of rotor spun composite yarn began in our country.First, the conventional rotor-spinning machine is modified by using a rotor with a hollow shaft and a filament guide tube and by adding a filament take-off device in order to produce a filament/staple fiber composite yarn. It is expected that the modification be feasible not only in laboratory but also in batch manufacture.Secondly, the effects of the twist multiplier and the draw ratio of the filament on the yarn properties are studied respectively. Comparing with the yarn produced by a conventional method, it is found that the tenacity and the breaking elongation of the composite yarn are higher and the CV value becomes lower. The final experiment data indicate that the independent change of twist multiplier and the draw ratio of the filament affects the properties of rotor-spinning composite yarn, such as the tenacity, breaking elongation, CV value and hairy index.Thirdly, the processing parameters for producing the rotor spun composite yarn are optimized by using the uniform design theory. The optimum technical parameters are 460 ~ 480 for the twist multiplier and 3.5 ~ 4.5 for the draw ratio of the filament.Finally, the mechanism of rotor spinning for producing the composite yarn is investigated primarily. By analyzing the longitudinalstructure of the composite yarn and the location of the filament and the staple yarn in it, it is thought that the yarn structure depends on the discrepancy between the filament tension and the staple yarn tension and the discrepancy controls the location and the path length of the two components in the composite yarn. Comparing with the conventional rotor spun yarn, the composite yarn is not directly made from the staple fibers and the filament yarn, but rather produced by combining the staple yarn and the filament yarn. In rotor composite yarn spinning, there are two yarn formation points for the staple yarn and the composite yarn. The formation point of the staple yarn is not stationary and moves around inside the rotor during yarn production.