As we all know, the pursuit of “softness” in products such as quilts and knitted underwear is always a major theme. In order to achieve “softness”, one of the requirements for yarns is to use as small a twist as possible. However, ordinary yarns are too small The twist will cause difficulty in spinning and increase the number of ends broken in weaving. Therefore, in the past, achieving “softness” could only balance spinning and weaving. Select a compromise value for the yarn twist requirements. The emergence of untwisted yarn provides another brand-new solution to achieve “softness” for quilt, knitting and other industries. The outstanding features of untwisted yarn products are their super “softness” and water absorption.
What is twistless yarn?
Twistless processing: A spinning method that uses an adhesive to bond the fibers in the fiber strips to each other into yarn.
After the roving is drawn by the drafting device, the whiskers are sent to the twisting drum, and the thin layer of adhesive from the tank box on the return drum is in contact. The fiber strip is transported forward by several small rotating pressure rollers and the drum. One of the small pressure rollers also makes axial reciprocating motion at the same time, twisting the fiber strip into a circular cross-section, and allowing each fiber to contact evenly. to the adhesive. The round fiber strips are dried by a heater, and the fibers stick to each other to form yarn. The spinning speed can be 2 to 4 times greater than conventional spinning methods, and the yarn produced can be used for weaving. An adhesive is used to bond the fibers in the yarn sliver to each other to form a yarn. There is no twist in the yarn sliver, and the strength is obtained by the mutual adhesion between the fibers. It is a new spinning method.
Uses of untwisted yarn
Home textile products (pajamas, bed blankets, quilts, towels, bath towels, shower caps, high-end uniforms, baby suits, Pillowcases, etc.) are characterized by softness, bulkiness, strong sweat absorption, cotton, warmth, lightness, transparency and thinness.
How is twistless yarn formed?
Yarling principle:
The wrapped yarn is composed of soluble PVA (polyvinyl alcohol) filament or mulberry silk wrapped on the surface of untwisted cotton bundles, which is used to weave towels. It has good wear resistance and can withstand a certain tension. Then after weaving into the finished product, PVA or mulberry silk is dissolved in water to make the loops in the fabric in an untwisted and fluffy state.
Yarn forming method:
1. Adhesive method
Use adhesive to tightly combine fibers with pseudo-adhesive effect together. The adhesion mixing of fibers can be done directly or during drawing. The yarn formed after the fibers are adhered and mixed on the draw frame can be directly supplied to the twistless worsted spinning machine after drying. It eliminates the four processes of traditional spinning process, namely two drawing processes, roving process and spinning process. This twist-free yarn-forming method can increase yarn output 10 times compared to ring spinning. It overcomes the obstacles of high output in ring spinning and rotor spinning. Yarn can be spun directly from slivers, and some can even be spun directly from combs. The output of net-spun untwisted yarn can be as high as 300~400 meters/minute. In addition, the distance between the draft rollers can be adjusted to adapt to the spinning of fibers of different lengths, thereby realizing the spinning of cotton yarn and yarn on the same machine. Wool yarn and other different types of yarn.
2. Soft wrapping method
This method uses parallel spinning to spin the first yarn. The primary yarn is composed of soluble filament fibers and untwisted parallel short fibers. The soluble filament fibers are spirally wound around the untwisted parallel short fibers. The filaments are dissolved during the finishing process, leaving only the core without Twisted short yarn. In this process, the role of the filaments is only to provide the tension required during the weaving process.
2.2.3 Reverse twisting method
Raw materials: water-soluble vinylon thread + cotton yarn Process: doubling → reverse twisting.
Technical points: The reverse twisting process is the most critical process for processing untwisted yarn
The number of reverse twists of the ply yarn should be equal to the spun cotton yarn and PVA yarn The twist degree
Use an appropriate small spindle speed
The height of the balloon should be appropriate
Appropriately increase the indoor humidity, increase the cohesion of vinylon, and reduce breakage
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Adjust the doubling tension and untwisting unwinding tension to solve the braiding phenomenon
Characteristics of untwisted yarn
① Because there is no The yarns in the fabric formed by twisting yarn are in a band-like or flat shape, which increases the coverage coefficient of the fabric. The fabric looks thick and tight, has a good fluffy feel, and the weight of the fabric can be reduced accordingly.
② Since the untwisted yarn has no twist and shrinkage, the shrinkage rate of the fabric formed is smaller than that of traditional fabrics, which can save raw materials.
③The fibers in untwisted yarn are exposed to the outside and can fully contact with the dye, so the dye is easy to dye, so the dyeing performance is better.
④The fibers in the fabric made of untwisted yarn have a high degree of parallelism, so they have a better gloss than the fabric made of twisted yarn.
Disadvantages of untwisted yarn
Untwisted towels feel super soft and thick, but during use, no matter how high-end untwisted, there will be some Hair loss is a shortcoming caused by the process that is difficult to eliminate. But we can wash it with warm water before use, which can remove most of the floating hair and improve the hair loss phenomenon.
Does untwisted yarn have twist?
Twistless yarn generally uses the soft wrapping method, which uses conventional spinning methods to spin the first yarn.
The soluble vinylon fiber is then wrapped around the surface of the virgin yarn to form a plied yarn. The customer melts away the water-soluble vinylon fiber during the finishing process, leaving only the virgin yarn on the cloth surface, making the cloth as soft as expected. The effect of��
In this process, the role of water-soluble vinylon fiber is only to provide the tension required in the weaving process to meet customer requirements.
What is the difference between untwisted yarn fabric and twisted yarn fabric?
1. Fiber arrangement
Untwisted yarn fabric because the fibers in the yarns forming the fabric are arranged in parallel, the fibers have a large degree of freedom, so the fibers form ribbons after being squeezed Shape or flat shape, which makes it have different characteristics from fabrics formed by traditional spinning methods.
2. Appearance
Due to the ribbon-like cross-section of the yarns in the fabric, the coverage coefficient of the fabric increases, so the fabric looks thick and tight. , the fluffiness is good, and the fabric quality is relatively light.
3. Processing technology
Since untwisted yarn has no twist shrinkage, the fabric shrinkage is smaller than that of traditional yarn fabrics, which can greatly save money. Saving raw materials; the dyeing performance of untwisted yarn fabrics is good, and a mercerized effect can be obtained. The fibers in untwisted yarn are exposed and can fully contact with the dye, so the dye is easy to be dyed. Twisted yarn often needs to be mercerized to make the fibers arranged more neatly to obtain good luster, while untwisted yarn does not need this One treatment; the fluffy effect of untwisted yarn fabrics can be used to weave lighter, thicker and more comfortable fabrics.
What is the difference between weakly twisted yarn and untwisted yarn?
In terms of durability:
Untwisted yarn: The durability of untwisted yarn is lower than that of weakly twisted yarn;
Weakly twisted yarn: The durability of weakly twisted yarn is The durability is higher than weakly twisted yarn and lower than veil.
In terms of twist:
Untwisted yarn: no twist;
Weakly twisted yarn: weakly twisted yarn does not complete the twist of the cotton yarn when spinning, Generally, only about 70% of the cotton yarn twist is completed.
In terms of advantages and disadvantages:
Untwisted yarn: The fabric of untwisted yarn feels super soft and thick, but there will be some lint loss during use, which is caused by the craftsmanship. The shortcomings that are difficult to eliminate can be washed with warm water before use, which can remove floating hair and improve the shedding phenomenon;
Weakly twisted yarn: it will not change significantly due to repeated exposure to water. Hard, the most important thing is that no additional environmental pollution will be produced during the production process.
1. Untwisted yarn is made by making the center of the fiber hollow. Weakly twisted yarn is a deformed yarn made by a deformation process in which two yarns are twisted together, heat-set, and then wound separately.
2. Weak twist: Cotton fiber and water-soluble vinylon are spun into yarn respectively, plied and twisted into threads. After the dimension is reduced during fabric finishing, the towel fabric can reach a high Softness and high absorbency. Weak twist means there is less twist (rotation) on the 10CM yarn, and no twist means there is no twist. Twisting the yarn is a means to improve the fastness of the yarn, but it will reduce the comfort, water absorption and breathability of the yarn. In terms of comfort, untwisted towels are worse than weakly twisted towels, but their durability is not as good as weakly twisted towels. </p
