Study On The Spinning Technology And Mechanism Of Rotor-spun Composite Yarn

In the last 30 years, the rotor spinning has become one of the most developed spinning methods. However, the composite rotor spinning is developing.First, the effect of the twist multiplier and the draw ratio of filament on the properties of rotor spun composite yarn is analyzed. It is found that the relationship between the yarn tenacity and the twist multiplier is quadratic, while the relationship between the yarn tenacity and the draw ratio of filament is linear. As the twist multiplier increases, the breaking elongation increases linearly. The relationship between the breaking elongation and the draw ratio of filament is quadratic. The optimum parameters are obtained by using the uniform design theory. For the 10s+70D composite yarn, the optimized twist multiplier is 460—470 and the draw ratio of filament is 4—4.5. For the 16s+70D composite yarn, the optimized twist multiplier is 510—515 and the draw ratio of filament is 3.75-4.25.Secondly, the forming and twisting mechanism of rotor spun composite yarn are studied. The yarn structure depends on the discrepancy between the staple yarn tension and the filament tension,therefore the structure varies with the change of the draw ratio of the filament. In the experiment, the wrapped yam is produced when the draw ratio of the filament is less than 2.5, the folded yam is produced when the draw ratio of the filament is between 2.5 and 3.3, and the core yam is produced when the draw ratio of the filament is more than 3.3. The twisting of the rotor spun composite yam includes staple yam twisting > composite yam twisting and false twisting or zero twist of the filament.Thirdly, the study of the tenacity and elongation of the rotor composite yam indicates the properties depends not only on the components of the yam but also on the yam structure. The tenacity of the > core yam is the highest and the one of the wrapped yam is the least. However, the wrapped yarn has the highest elongation and the folded yam has the least elongation.Fourthly, the elasticity of the cotton/polyurethane core yam is tested and analyzed. The results indicate that the core yam has an excellent elongation and recover property. Its elasticity increases with the increase of the linear density, the content and the draw ratio of the polyurethane filament. The elasticity is affected predominantly by the filament draw ratio, and is also affected by the twist multiplier.Finally, the properties of rotor spun composite yarn are compared with those of corresponding ring spun composite yam. The result indicates that their discrepancy is similar to the one between theconventional rotor spun yam and the conventional ring spun yam. The rotor composite yarn has less tenacity and elongation than corresponding ring spun composite yam, and smaller CV value and hairy index than ring spun composite yam.Ren Xiuhong (textile engineering) Supervised by Wang Xinhou...