Different short fiber yarn processing technologies have different effects on the physical properties and The appearance is different, and even the characteristics of the final product are different.
1. Different spinning methods 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. The outer structure includes the appearance and surface structure 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. The internal structure of the fiber orientation, elongation, displacement and twist includes: the strength of the yarn; the degree of fiber mixing; resistance Bending strength; compressibility; 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.
3. Hairiness
Flying 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. Apply zweigle hairiness. The test proposes to classify hairiness of 1-2 mm and separate harmful hairiness of more than 3 mm. If the hairiness of ring-spun yarn is 100%, the hairiness of compact ring-spun yarn, vortex yarn and rotor yarn is 1-2 mm higher than that of ring-spun yarn. Hairiness reduction, double nozzle false twist wrapped yarn, Package situationIt is poor and has more hairiness. The So-Called test can be used to detect the flying particles formed by the friction surface during the post-process processing of the yarn. The friction force should be measured with a rubber ring. Compact yarns have better friction resistance than non-traditional yarns. The protruding hairiness of rotor yarn is less, especially viscose fiber. The fibers on the yarn will not break, but many hairs are wrapped around the yarn body by the wrapped fibers, so the hairiness of rotor yarn is less.
4. Volume of yarn
Yarn volume is an important indicator that reflects yarn coverage ability. When compact-spun ring-spun yarn and ordinary ring-spun yarn have the same twist, the latter’s final product has lower coverage ability. Compact-spun ring-spun yarn can appropriately reduce the twist to increase yarn volume while maintaining the same strength. It can obtain a covering capacity equivalent to that of ordinary ring-spun yarn, and the twist can be reduced by 5-10%. The Denkenolorr yarn structure tester provides the measured yarn volume with a yarn length of 0.3 mm. 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 around the core of the yarn, and the length is very short so that many parts of the yarn are essentially untwisted.
The friction resistance and stress load of the warp yarn are Using the So-Called analog indicator, the required 15 yarns can be tested 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 technology has its shortcomings. This new type of spinning must be processed when making warp yarns. In air-jet spinning technology, compared to true twisted yarn, there are very few fibers on the yarn. In the case of straight winding, the mechanical and physical properties of the yarn are different, especially when winding (winding), which is more obvious. This is also the difference between non-traditional spinning and ring-spun yarn.
5. Internal structure of yarn
The formation of fibers inside the yarn is related to the external structure of the yarn, the arrangement of the yarn core inside the yarn, and the fibers along the yarn The lengthwise extension 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. The yarn strength characteristics are related to the clamping length during the test, reducing details and weak strength. Possibility of rings:
Normal yarn strength is at a clamping length of 520 mm Tested on the strength machine, there are also clamping lengths of 100 mm and 18 mm. The clamping length decreases and the yarn breaking strength increases. This is due to the short clamping length and weak strength.The probability of occurrence of rings and details is reduced, the length of breakage 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 length 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 greater the breaking strength of the yarn. It can be seen from the traces after the electronic photography that the rotor yarn has a winding structure. Even if the clamping length is less than 5 mm, 100% of the fibers will be clamped and the fibers will break. When the clamping length is 0 mm, the fiber breakage length will be lower than the fiber length. The length and poor directionality of the yarn core fibers result in low breaking strength.
The strength of air-jet yarn is equal to that of ring-spun yarn. Between compact yarn and rotor yarn, it is mainly air-jet yarn. The yarn core is parallel to that of rotor yarn, with less wrapping fiber and less strength than rotor yarn.
6. The formation of yarn affects yarn deformation Characteristics, such as yarn bending strength, are characteristics affected by the yarn formation process, but the detection of yarn bending strength is difficult. A new method for detecting yarn resistance has been developedA powerful way to bend. 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 deforms This is the situation where the yarn becomes flat and deformed after being compressed on the cross section of the warp and weft yarns. Detection of yarn thick places shows that when the yarn compression force increases, the thick places decrease.
The fiber distribution caused by the rotor yarn structure , where the fibers are wrapped, the hand feels harder, and the deformation force of the yarn 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 100CN pressure conditions, which showed that the yarn has a good twist structure. There are about 95% parallel untwisted fibers in the MTS double-nozzle air-jet yarn with the same deformation. More It is easy to deform. According to this test, the rotor yarn feels relatively hard. The yarn deformation can be detected by the tightness of the yarn on the loom or knitted fabric.
7. Yarn resilience
The rebound of yarn is very important for textile processing, for exampleFor example, knitted fabrics are skewed and deformed. 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 different knots. are lower.
Air-jet spinning has low resilience, mainly Because of the higher proportion of parallel untwisted fibers, true-twisted yarns are more resilient than non-traditional yarns, resulting in less fabric skew when further processed into knitted fabrics.
Yarn structure is one of the important characteristics of yarn First, the appearance of the yarn is related to the properties of the yarn. The arrangement of fibers inside the yarn has a great influence on the properties of the yarn, especially the further processing of the yarn and the properties of the final product. Poor yarn structure has a great impact on post-process processing. Good 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. Currently, there are five practical and highly concerned spinning methods in the field of cotton spinning, namely traditional ring spinning, rotor spinning, air-jet spinning, vortex spinning and improved ring spinning – compact spinning. The ring spinning method has a history of more than a century and a half, and the latter four have been developed in recent decades or even in recent years, collectively referred to as the newtype spinning method. Different spinning methods have their own unique characteristics in terms of output, quality, and yarn structure and characteristics.
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