1. Physical properties of short fibers
Different short fiber spinning technologies have different effects on the physical properties of yarns The impact on the appearance and appearance is different, and even the characteristics of the final product are also different.
(1) Different spinning methods have different effects on yarn structure. The structure of short fiber yarn is different from that of filament yarn. The first is the arrangement of the outer and inner fibers of the yarn. External structure includes the appearance and surface texture of the yarn. Such as: the arrangement of fibers on the surface of the yarn; the hairiness of the yarn; the friction coefficient of the yarn; the characteristics of the yarn; the wear resistance of the yarn and other surface characteristics.
(2) The internal structure of the yarn is mainly the entire cross-section of the yarn body and the longitudinal arrangement of the yarn, fiber directionality, elongation, displacement and twist The internal structure includes: the strength of the yarn; the degree of fiber mixing; the bending strength; the compressibility; and the resilience (tendency to kink).
The above explanation of structural implications is not necessarily complete, but it provides a sense of the complexity of yarn properties.
2. Spinning technology
In order to obtain the influence of spinning technology on yarn structure The concept uses 3dtex and 38 mm viscose staple fiber to conduct trial spinning in 5 different spinning process systems.
A\Traditional ring spinning technology; B\Compact spinning ring spinning technology; C\Double nozzle (MTS) false wrap spinning Technology; D\vortex spinning (MVS) spinning; E\rotor spinning.
(1) The external structure of the yarn mentioned above can be seen on a scanning electron microscope camera. Applied microelectronic photography photos: including rotor spinning, air-jet spinning, vortex spinning, ordinary ring spinning and compact ring spinning. From the photos, you can see the external fiber orientation of the yarn produced by the five processes, among which the tight ring spinning More information on the external structure of the spindle yarn Multi-fiber yarn is formed, and almost all fibers are formed in the yarn body. The short fiber yarn is improved. The twist structure of the yarn is clearly seen, and one end of the fiber is twisted into the yarn body along the length of the yarn, and the orientation of the tightly ring-spun yarn is Good sex.
(2) Traditional ring spinning, under the same twist conditions, the surface of traditional ring spinning is disordered, a large number of fiber tail ends are not twisted into the yarn body, and single fibers extend outside the yarn body. This may be due to the ring/traveller or yarn guide.
(3) Vortex spinning is similar to ring spinning. The fibers are well arranged in the yarn body. When the spinning speed is 350/min, the wrapped fibers are in a fine spiral shape. The twist is basically the same as ring spinning. Same, the actual twist of the yarn is the same as the calculated twist base The ratio of the wrapped fibers to the untwisted core fibers is very high, and almost all of the yarn core fibers are covered. Therefore, the appearance of the vortex yarn is basically similar to that of the ring yarn, and the outer wrapped fibers are similar to those of the untwisted ones. The yarn cores come together to form a true twist.
(4) Double-nozzle false-twisted yarn, double-nozzle false-twisted yarn, is essentially different from vortex yarn. The wrapped fibers of double-nozzle air-jet yarn only account for all the fibers. About 90% of the 6%-8% fibers are stretched and untwisted. It can be clearly seen that the wrapped fibers wrap the yarn core more tightly than the vortex yarn.
(5) Rotor spinning, regardless of whether the rotor yarn belongs to the true twist category, the fiber arrangement on the rotor yarn is disordered. The fibers in the middle of the yarn show no clear spiral shape in the Z and S directions, and the fibers are straight. . It can be clearly seen that the wrapped yarn is not tangled, which is the advantage of rotor yarn and the basis of its characteristics.
3. Hairiness
The fly and hairiness caused by spinning are a very troublesome problem. Hairiness has many negative effects during downstream processing. Textile feel and final product properties are affected by hairiness. Application of zweigle hairiness test Classify hairiness of 1 mm-2 mm and separate harmful hairiness of more than 3 mm. If the hairiness of ring spun yarn is 100%, then compact ring yarn, vortex yarn and rotor yarn 1. The mm-2mm hairiness is less than that of ring-spun yarn. The double-nozzle false-twisted wrapped yarn has poor wrapping conditions and more hairiness. The SO-Called detector can be used to detect the formation of yarn due to friction during post-processing. of flying flowers, the friction should be controlled by the rubber ring. Measurement. Compact yarn has better friction resistance than non-traditional yarn. The hairiness of rotor yarn is less, especially viscose fiber. The fibers on the yarn will not break, but many hairs are entangled in the wrapping fiber. On the yarn body, the rotor yarn has less hairiness.
4. Volume of yarn
Yarn volume is an important indicator that reflects the coverage ability of the yarn. When compact-spun ring-spun yarn and ordinary ring-spun yarn have the same twist, the latter’s final product coverage ability is lower. Compact-spun ring-spun yarn maintains the same Power strip The twist can be appropriately reduced to increase the yarn volume, and the covering capacity of ordinary ring-spun yarn can be obtained, and the twist can be reduced by 5% to 10%. Denkenolorf yarn structure tester providesMeasured yarn volume with a yarn length of 0.3mm. The detection of yarn volume includes double-nozzle MJS air-jet yarn with the same yarn count. Since the air-jet yarn is a wrapped yarn and false twist, the volume of the same yarn count is larger than that of the ring-spun yarn. The graphics taken with microelectronic scanning photography technology show that , a small amount of wrapped fiber is wrapped on the yarn core, and the length is very short, so that many parts of the yarn are basically untwisted.
The friction resistance and stress load of warp yarns are simulated indicators using So-Called, which can test the required 15 yarns at the same time. The fiber arrangement of ideal compact ring-spun yarn is shown to be superior to that of ordinary ring-spun yarn. Non-traditional spinning technologies all have shortcomings. This new type of spinning must be processed when making warp yarns. In air-jet spinning technology, compared to true twisted yarns, there are very few fibers on the yarn, and there is a situation of straightening and winding. , therefore, the mechanical and physical properties of the yarn are different, especially during winding (winding). This is the difference between non-traditional spinning and ring-spun yarn.
5. Internal structure of yarn
The formation of fibers inside the yarn and the outside of the yarn Related to the structure, the arrangement of the yarn core inside the yarn and the extension of the fibers along the length of the yarn can be obtained through electronic scanning photography during the drafting process. From the yarn cross section, it can be seen that the fibers are highly parallel and affect the yarn strength and yarn strength. The strength characteristics are related to the clamping length during testing.
Reduce details and the possibility of weak strength loops: Normal yarn strength is tested on a strength machine with a clamping length of 520 mm, and there are also 100 mm and 18mm clamping length. The clamping length is reduced and the yarn breaking strength is increased. This is because the clamping length is short, the probability of strong weak loops and details is reduced, the breaking length is reduced, and the chance of breakage is less. If the fiber distribution is well oriented, the test clamping length is reduced, and the yarn breaking strength is significantly increased, especially for ring-spun yarn and compact ring-spun yarn. The breaking strength of rotor yarn is low. Even if the breaking length is lower than the fiber length, the breaking strength of rotor yarn will not increase even if the breaking length is short due to the hook formed by the fiber. In short, the more yarn fibers are clamped, the better the longitudinal orientation of the fibers, and the yarn breaking strength increases. It can be seen from the electronic photographic scan that the rotor yarn has a winding structure. Even if the clamping length is less than 5mm, 100% The fiber is clamped and the fiber breaks. The clamping length is 0 mm, the fiber breaking length is lower than the fiber length, and the poor orientation of the yarn core fiber results in low breaking strength.
The strength of air-jet yarn is between ring yarn, compact yarn and rotor yarn. It is mainly air-jet yarn. The yarn core is parallel to that of rotor yarn, and it is wrapped There are relatively few fibers and the strength is less and higher than that of rotor yarn.
6. The formation of yarn affects the characteristics of yarn deformation
For example, the bending resistance of yarn is a characteristic affected by the yarn formation process, but the bending resistance of yarn is Detection is difficult. A new method for testing the bending strength of yarns has been developed. Tests have shown that if the bending strength of compact yarn is 100%, then the bending strength of rotor spinning and vortex spinning is 200%, and the double-nozzle air-jet yarn is 300%. These numerical relationships can be obtained from some non-traditional spinning, in woven fabrics and knitted fabrics Compared with ring-spun yarn, the fabric feel of non-traditional spinning yarn is thicker and harder than that of ordinary ring-spun yarn products. There is also a small difference in bending strength between ordinary ring-spun yarn and compact yarn.
Another problem arises. When the yarn is deformed, the yarn becomes flat and deformed after being compressed on the warp and weft cross-section. Detection of yarn thick spots It shows that when the yarn compression force increases, the thick place decreases.
The rotor yarn structure causes fiber distribution. At the fiber wrapping area, the hand feels harder and the deformation force is smaller than that of the yarn without wrapping. Knitted fabrics and woven fabrics produced by rotor yarn often have an uneven, thicker and harder appearance than ring-spun yarn.
For comparison, the yarn slugs were tested under 1OOcN pressure conditions, which showed that the yarn had a good twist structure and the same deformation of MTS double-nozzle air-jet yarn About 95% of the fibers are parallel and untwisted, which is more prone to deformation. According to this test, the rotor yarn feels relatively hard. The yarn deformation can be detected by the tightness of the yarn on the appearance of the loom or knitted fabric.
7. Yarn resilience
Yarn resilience is an important factor in textile processing It is very important, such as the skew deformation of knitted fabrics. Resilience is measured by detecting the knotting force of the yarn. The resilience of truly twisted yarns such as compact ring-spun yarns and ordinary ring-spun yarns is different from that of non-traditional yarns. Rotor yarns with forward twist or reverse twist have even knots. lower.
The resilience of air-jet spinning is low, mainly because of the higher proportion of parallel untwisted fibers. True-twisted yarn has greater resilience than non-traditional yarn, so in the further There is less fabric skew when processed into knitted fabrics.
8. Conclusion
Yarn structure is one of the important characteristics of yarn. The appearance is related to the yarn properties. The internal fiber arrangement of the yarn has a great influence on the yarn properties, especially the further processing of the yarn and the properties of the final product. Poor yarn structure affects post-processingSequential processing is very influential. The applied yarn structure has particularly good functions and is also very useful. The appearance structure of textiles with tightly spun yarns is ideal in terms of adaptability.
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