False-twisted elastic yarn takes advantage of the thermoplastic properties of synthetic fibers such as polyester and nylon. When the fiber is twisted and curled, it is heated and set to fix its twisted and curled state to obtain fluffy, elastic and twist-free yarn. Stretch yarn is called false-twisted stretch yarn because the yarn has a slight torque but no twist and has good elasticity.
There are five main types of false twisted elastic yarn
(1) General false-twisted silk
That is, the fiber is twisted to a certain shape and then untwisted. The silk thread maintains the bulkiness of the twisted state, but has no twist. The traditional processing method uses the above three-step method, but currently it is completed in one step on the false twist elastic yarn machine. Its fibers have good torsion and elasticity, so crepe fabrics and elastic fabrics with better crepe effect can be developed.
(2) Really twisted and falsely twisted silk
In order to make the product The fluffy false-twisted elastic yarn not only achieves a comfortable effect, but also has ideal bunching properties, so that the fabric can obtain a good texture effect. People then add a certain degree of twist to the false-twisted elastic yarn machine to form a solid twist. False twisted stretch yarn. At present, real twist and false twist elastic yarn can be completed on the false twist and real twist one-step texturing machine.
(3) Slub yarn
Mixing false twisted elastic yarn with other monofilaments And twisting, due to the gap overfeeding, the surface of the mixed fiber has regular bamboo segments, which are completely covered by leather filaments, while the non-bamboo segments are twisted side by side with leather filaments and core filaments. This is Slub silk developed on the market (Figure 9). There are more than 10 varieties currently developed, such as white polyester FDY (fully drawn yarn) as leather yarn, white polyester FDY as core yarn, knotty yarn that mainly embodies the embossed effect of the bamboo section. Common specifications are 240dtex/60f.
Cationic polyester FDY is leather yarn and white polyester FDY is core yarn. It mainly embodies the cationic color absorption effect of the bamboo section. Common specifications are 222dtex/54f, 226dtex /60f. White polyester FDY is leather yarn and white nylon FDY is core yarn. It mainly reflects the white effect of bamboo segments. Common specifications are 222dtex/56f (200 denier/56f) and 222dtex/60f (200 denier/60f). The length of the bamboo sections of slub silk ranges from 1 to 15cm, and the number of bamboo sections per meter can be adjusted from 3 to 10. The tightness of the bamboo sections can be caused by tight cohesion without slipping, or it can be caused by loose cohesion. slip.
(4) Uneven false twist silk
Using MOY (medium-speed spinning) polyester or POY (pre-oriented yarn, high-speed spinning) polyester as raw materials, it is made by drawing and false twisting on a one-step machine. In the drafting section, the thick details of the yarn are produced due to the difference in stretching. After the deformation of the false twist section, the yarn has both a thick appearance and fluffy performance. The produced textured yarn with thick details is said to be uneven. False twisted silk.
Due to the innovation and improvement of the false twist texturing machine, which allows two kinds of raw materials to be fed and processed through double wire channels at the same time, product varieties have been increased, such as those with long slugs and short details. The raw material formed by the network of uniform polyester yarn as the sheath and FDY (fully drawn yarn) polyester as the core can have 1 to 3 thick spots per meter, and no one has 2 to 6 cm of thick spots.
It is a raw material formed by using uneven polyester yarn with short thick sections and long details as the sheath, FDY polyester as the core, and a network. It is a raw material formed by using cationic polyester with short slubs and long details as the sheath, FDY polyester as the core, and a network. It is a raw material formed by cationic polyester with short slugs and ordinary polyester with short slugs juxtaposed and networked.
(5) Mixed twist and false twist silk
During yarn processing, there are two types of twist, positive and negative, in the twisting and untwisting areas. Therefore, generally speaking, the positive and negative twists cancel each other out and become “no twist”, while in some parts of the yarn, there is positive and negative twist. , reverse twist, thus forming mixed-twisted and false-twisted textured yarn (Figure 10), which has two types: single-strand type and mixed fiber type.
The single-strand type is a single-filament mixed-twisted false-twisted yarn. The twisted section of the silk strip shows a finer twist due to the tight wrapping of the fiber, while the untwisted section The silk body is fluffy and thick, and the length of the twist and thick joints can be adjusted. The mixed fiber type combines two types of single-filament mixed-twisted and false-twisted yarns to form a two-color effect, a different shrinkage effect, and three combinations of random polyester, cationic polyester and colored yarns of the two fibers.
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