Study On Improving Properties Of Ring Spun Yarn By The Synergistic Effect Between Wetting And Low-twisting Spinning

Ring spinning process holds the leading position in the spinning field due to its wide adaptability of fiber raw materials,large compatibility of yarn counts and good properties of resultant yarn.When spin low-twist yarn on ring spinning frame,the production efficiency is high and the residual torque of yarn is small.The textile structure is fluffy soft and waxy,therefore low-twist yarns are usually used in infant clothing and intimate underwear.However,when spinning cotton low-twist yarn,the dynamic strength of the spinning segment is low,and the yarn is broken frequently.In addition,there are problems of low-twist yarns such as weak strength and excessive hairiness that affect the weaving process.Although the performance of low-twist yarn has been improved by using the false twist device,the yarn hairiness is still not satisfactory.In this study,a non-contact single spindle atomizing wetting device was designed and worked with a false twist spinning device to solve the problem of high hairiness of low twist yarns and improve the performance of low-twist yarns comprehensively.The dynamic twist of the spinning segment was improved and the dynamic twist distribution of the yarn was changed by false twist.And the water mist could moisten the yarn hairiness of spinning segment,so the yarn hairiness was reduced.Moreover,the spinnability and strength of the low-twist yarn were improved by false twist.Firstly,contact wetting device prevents the transport of twist and cannot work simultaneously with the false twist device.Therefore,a non-contact single spindle atomization wetting device was designed for wetting the yarn in the spinning segment,and the influence of the wetting process on the yarn properties was investigated in this study.The water mist was generated by ultrasonic oscillation,which was used to moisten the hairiness and roll them into the yarn body with the help of the compression of the yarn guide hook and the twist change of the yarn.The device was composed of a fixing device,a water-supplying pipe,an external liquid-supplying system,an ultrasonic oscillating plate and a circuit control board.To explore the best direction and amount of humidification,spinning experiments were conducted with different humidification direction and amount parameters,and yarn properties influenced by automatic wetting device were examined,and the changes of yarn hairiness before and after winding were compared.The results showed that the harmful hairiness of the yarn could be effectively reduced by applying the automatic single spindle wetting device.After winding,the hairiness of wetting yarn was still less than that of the ordinary ring yarn.The optimal parameters of the automatic single-spindle wetting device were 40° and 30 ml/h.Secondly,the polyurethane false twist belt was replaced by silicone false twist belt on ring spinning machine to solve the problem of low friction efficiency,and the influence of the false twist process parameters on the yarn performance was investigated in this work.In order to improve the efficiency of the false twisting device,the material and diameter of the friction belt were optimized.High speed camera was used to measure the dynamic twist of spinning section with different false twist belt,and the yarn properties were compared.In addition,the influence of speed ratio on yarn quality between false twist belt was examined,and the hairiness,strength and elongation,evenness of yarn were tested.Under the optimum operating parameters of the false twist device,the twisting range of the low-twist yarn that could be spun by the false twist technology was explored.The results showed that the friction coefficients of different false twist belts were different,and the friction coefficient of the silicone false twist belts was the best.When the speed ratio was increased within a certain range,the yarn quality was improved.When the speed ratio was too high,the false twist efficiency of the yarn was improved slowly.Moreover,the runouts between the yarn and the friction belt were increased,which deteriorated the yarn quality.The optimal diameter of the silicone false twist belt was 6 mm,and the optimal speed ratio between the false twist belt and the yarn was 1.5.Finally,the application results of aligning atomization non-contact single-spindle humidification with friction belt false twisting were evaluated.The wetting low-twist spinning technology was used to increase the dynamic twist of the yarn at the spinning segment and improved the morphology and tension of the spinning triangle.Meanwhile,the low-twist yarn hairiness was wetted by atomization and attached to the low-twist section below the false twist belt,and the yarn hairiness were wound into the yarn body by the compression of the yarn guide hook and the increase of twist.The effects of aligning atomization with false twisting on the tensile property,hairiness and residual torque of low-twist yarn were mainly explored,and the influence of twist coefficient on the performance of low-twist yarn were investigated.The variation law of residual torque of yarn was judged by the degree of coil skew of weft knitted fabric.The results indicated that wetting low-twist spinning could improve the hairiness and strength of low-twist yarn better than normal twist yarn,and reduce the residual torque of normal twist yarn better than low-twist yarn.Under the optimized wetting false twisting parameters,14.6 tex cotton wetting low-twist yarn with twist factor 260 was spun.The results showed that the harmful hairiness was reduced by 44.6%,the breaking strength was increased by 19.1%,the residual torque was decreased by 11.1%,and the fabric skew angle was reduced27.9%.