Effect of various spinning methods on yarn properties

 1, the physical properties of staple fibers

  Different short fiber spinning technology has different effects on the physical properties and appearance of the spun yarn, and even affects the characteristics of the end product.

  (1) different spinning methods on spinning yarn structure, short fiber yarn structure and filament different, first of all, the yarn's external and internal fiber arrangement, the external structure contains the yarn's appearance and surface structure. Such as: the arrangement of fibers on the surface of the yarn; yarn hairiness; yarn friction coefficient; yarn characteristics; yarn wear and other characteristics of the surface.

  (2) The internal structure of the spun yarn is mainly the entire cross-section of the fiber in the yarn body and the longitudinal arrangement of the yarn, the fiber orientation, elongation, displacement and twist. The internal structure contains: the strength of the yarn; the degree of fiber mixing; bending strength; compressibility; resilience (tendency to bond).

  The above explanation of the meaning of the structure is not certainly complete, but provides the complexity of spinning yarn characteristics.

  2. Spinning process

  In order to obtain the concept of the effect of spinning process on the structure of spinning yarn applied 3dtex, 38 mm viscose staple fiber, in five different spinning process systems for trial spinning.

  A\ conventional ring spinning process; B\ compact spinning ring spinning process; C\ double nozzle (MTS) false idea wrapping spinning process; D\ vortex spinning (MVS) spinning; E\ rotor spinning.

  (1) As mentioned above, the external structure of the spun yarn can be seen on the scanning electron microscope photographer. Application of micro-electron photography photo: contains rotor spinning, air-jet spinning, vortex spinning, general ring spinning and compact ring spinning five, from the photo can see the five processes produced by the external fiber orientation of spinning yarn, which compact ring spinning yarn in the external structure of more fibers to form spinning yarn, almost all fibers formed in the yarn body, improved short fiber yarn, the twist structure of the yarn to see very clearly, and the fiber end along the yarn The twist structure of the yarn is clearly visible and the fiber end is flicked into the yarn body along the length of the yarn.

  (2) traditional ring spinning, twist the same conditions of traditional ring spinning surface disorder, a large number of fibers end not twisted into the yarn body, a single fiber stretched outside the yarn body, may be due to the steel collar / wire ring or yarn guide caused.

  (3) Vortex spinning, close to ring spinning, the fibers are well aligned in the yarn body, spinning speed 350 / min, the wrapped fibers are in a fine spin. The twist is basically the same as that of ring spun yarn, the actual twist of the yarn and the calculated twist are basically the same. The ratio of wrapped fibers to non-twisted core fibers, accounting for a high percentage, almost all the core fibers are covered, so the appearance of the vortex yarn is basically similar to that of ring spun yarn, and the external wrapped fibers form a true twist together with the non-twisted core.

  (4) double nozzle false twist yarn, double nozzle false twist yarn, and vortex yarn is actually different in substance, double nozzle jet yarn wrapped fibers account for only 6%-8% of all fibers about 90% of the fibers are stretched without twist, you can clearly see the wrapped fibers on the core of the yarn wrapping tightness than vortex yarn.

  (5) Rotor spinning, regardless of whether the rotor yarn belongs to the real twist category, but the rotor yarn on the fiber arrangement is disorderly, the fiber in the middle of the yarn shows no clear spiral in the Z direction and S direction, the fiber is straight. This is the advantage of the rotor yarn and is the basis of the characteristics of the rotor yarn.

  3. Feathering

  Hairiness has many negative effects in the downstream finishing process. The feel of the fabric and the nature of the final product are affected by hairiness. If ring spun yarn hairiness is 100%, compact ring spun yarn, vortex yarn and rotor yarn 1 mm-2 mm hairiness is less than ring spun yarn hairiness, double nozzle false twist wrapped yarn, wrapped condition is worse, hairiness is more, application SO-Called detector can measure the flying flowers formed by friction when spun yarn is finishing in the post process, friction force is measured by applying rubber ring. Compact yarns are better than non-traditional yarns in terms of friction resistance. Rotor yarn stretches out less hairiness, especially viscose fiber is more obvious, the fiber on the yarn will not break, but many hairiness are wrapped around the yarn body by the wrapped fiber, so the rotor yarn hairiness is less.

  4、Volume of yarn

  Spinning yarn volume is an important indicator of spinning yarn covering ability, compact spinning ring yarn and general ring yarn in the same twist, the latter end product covering ability is lower. Compact ring spinning yarn in maintaining the same strength conditions can be appropriately reduced twist to increase the volume of spinning yarn, can obtain the equivalent of the general ring spinning yarn covering capacity, twist can be reduced by 5% to 10%. The Denkenolorf spinning yarn structure tester provides the measured spinning yarn volume for a spinning yarn length of 0.3 mm. The spinning line volume test contains the same spinning line count double nozzle MJS jet yarn, because the jet yarn is wrapped yarn, false twist, so the same yarn count than the ring spinning yarn volume, using micro-electron scanning photography technology to take pictures show that a small amount of wrapped fibers on the core, and the length is very short so that many parts of the spinning line fibers are basically untwisted.

  Abrasion and stress loads of the warp yarn are applied to the So-Called modelling index, and the required 15 yarns can be tested simultaneously. The fiber arrangement of the ideal compact ring spinning yarn shows superiority over the average ring spinning yarn. Non-traditional spinning technology have shortcomings, this new spinning yarn must be treated when doing warp yarn, in the air-jet spinning technology, compared to the true twist yarn, the spinning line has few fibers, there is a straightening and winding, therefore, the spinning line mechanical and physical properties are not uniform, especially in the winding (winding) is more obvious, or non-traditional spinning yarn and ring yarn difference.

  5, spinning yarn internal structure

  Spinning line internal fiber formation and spinning line external structure related, spinning line internal yarn core arrangement, fiber extension along the length of the spinning line can be obtained after electronic scanning photography in the drafting process, from the spinning line cross-section to see the fiber height parallel and affect the spinning line strength, spinning line strength characteristics and test when the clamping length related.

  Reduction of details and the possibility of weak loops in strength: The normal spun yarn strength was tested on a strength machine with a clamping length of 520 mm, but also with clamping lengths of 100 mm and 18 mm. The reduction of clamping length and the increase of spun yarn breaking strength is due to the short clamping length, the probability of strong weak rings and details is reduced, the breaking length is reduced and the chance of breaking is less. If the fiber distribution is well oriented, the test clamping length is reduced and the spun yarn breaking strength increases significantly, more obvious for ring yarn and compact ring yarn. Rotor yarn breaking strength is lower, even if the breaking length is lower than the fiber length, due to the formation of fiber bending hook, even if the breaking length is short, rotor yarn breaking strength will not increase. In conclusion, the more fibers are clamped in the spinning yarn, the better the longitudinal orientation of the fibers and the increase in the breaking strength of the spinning yarn. From the electronic photographic scan, we can see that the rotor yarn is a winding structure, even if the clamping length is lower than 5 mm, it will make 100% of the fibers are clamping and fiber breakage, the clamping length is 0 mm, the fiber breakage length is lower than the fiber length, the core fiber orientation is poor resulting in low breaking strength.

  The strength of air-jet yarn is between ring yarn, compact yarn and rotor yarn, mainly air-jet yarn, the core is parallel than rotor yarn, the wrapped fiber is less, the strength is less high than rotor yarn.

  6, yarn formation affects the characteristics of spinning yarn deformation

  Such as yarn resistance to bending strength is the spinning yarn formation process influences the characteristics, but the detection of spinning yarn resistance to bending strength is very difficult. A new method has been developed to detect the bending strength of spinning yarn resistance. Tests show that if the tight yarn bending strength of 100%, then the rotor spinning and vortex spinning for 200%, double nozzle jet yarn for 300%, these numerical relationships can be from some non-traditional spinning, in woven and knitted fabrics and ring yarn for comparison, non-traditional spinning fabric feel than the general ring yarn products coarse hard, general ring yarn and tight yarn between the bending strength is also a small difference.

  Other problems arise when the spinning yarn deformation in the warp and weft yarn cross-section of the spinning yarn after the pressure becomes flat deformation situation. The detection of spinning line coarse knot shows that when the compression force of spinning line increases, coarse knot decreases.

  The structure of the rotor spinning yarn causes the fiber distribution condition, at the fiber wrap, the feel is stiffer, than the yarn without the wrap deformation force is smaller. Rotor yarn production of knitted goods and woven fabrics tend to make the appearance than ring spun yarn uneven, coarse and stiff.

  For comparison, the spinning yarn coarse section in 1OOcN pressure conditions test, indicating that the spinning yarn has good twist structure, the same deformation of the MTS double nozzle jet yarn in about 95% parallel untwisted fibers, more simple to produce deformation, according to this test, the spin cup yarn feel harder, in the loom or knitted fabric appearance can be detected by the tightness of the yarn deformation of spinning yarn.

  7, the resilience of spinning yarn

  The resilience of spinning yarn is very important for fabric finishing, such as knitted fabric to produce skewed deformation. Resilience is measured by testing the spinning yarn bonding force, tight ring spinning yarn, general ring spinning yarn and other true twist yarn and non-traditional yarn between the resilience of different, turn cup yarn positive twist or reverse twist of the yarn its bonding are lower.

  Air-jet spun yarn has lower springback force, mainly because of the higher proportion of parallel non-twisted fibers, and the real twisted yarn has higher springback force than the non-traditional yarn, so the fabric is less skewed when further finishing into knitted fabric.

  8. Conclusion

  Spinning yarn structure is one of the important characteristics of spinning yarn, spinning yarn appearance and spinning yarn properties related to the internal fiber arrangement of spinning yarn has a great impact on the spinning yarn properties, especially on the further finishing of spinning yarn and the end product properties more significant impact. Poor spinning yarn structure on the post-process finishing is very influential, the application of good spinning yarn structure has a very good function, the use is also very good, in the adaptable performance of closely spun yarn fabric products, the appearance of the structure is ideal.



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