Product development for air-jet spinning
Product development for air-jet spinning
Air-jet spinning is a new technology in the current spinning field and has many advantages. However, it is uneconomical to use air-jet spinning to produce conventional yarn products. The article introduces the ideas and experience of developing high value-added yarns using air-jet spinning machines.
Air-jet spinning has become a high-tech technology attracting attention in the domestic and foreign textile industries due to its comprehensive technical level and economic advantages such as excellent yarn quality, short process, high output, wide spinning range, low labor usage, and high degree of automation. For this reason, our factory introduced MJS No. from Murata of Japan in early 2001. 802HR.
However, many problems also arise. As a new spinning method. Air-jet spinning does have many advantages, but when the unique yarn structure of air-jet yarn has not been generally accepted, it is inevitably somewhat impractical to use it to produce conventional yarn products (such as T/C type). First of all, the selling price of such products cannot consume high depreciation; secondly, in recent years, the yarn price war caused by the over-expansion of the overall scale of the textile industry has caused the profits of enterprises to shrink day by day. Therefore, from the day the equipment was introduced, it has been a curse restricting the rapid development of our factory. Finding high value-added products that can be produced on this equipment became the primary issue that had to be solved.
1 Yarn structural characteristics of air-jet yarn
The weaving mechanism of air-jet yarn (also called MJS yarn) is to use the high-speed rotating air flow field of a two-stage nozzle to blow and twist the outer fibers of the fiber assembly, so that they cover the inner fibers to form air-jet spinning yarn. That is, the cooked strips enter the nozzle system after being drafted by the four-roller double-apron drafting mechanism. The nozzle system is composed of two second nozzles with opposite airflow directions connected in series. Because the pressure of the second nozzle is greater than that of the nozzle. The core whiskers formed after passing through the nozzle are reversely coated with a layer of wrapping fibers when passing through the second nozzle. It can be seen under a high-power microscope that the air-jet yarn has a composite structure, that is, one part is an untwisted (or very small twist) core yarn, and the other part is a wrapping fiber wrapped around the outer edge of the core yarn. The wrapping fiber exerts a centripetal force on the core yarn. The cohesion between fibers is greatly improved, thereby polymerizing into yarn. Therefore, the structure of air-jet yarn is completely different from that of ring-spun yarn.
2 Ideas for air-jet spinning product development
The original intention of introducing this equipment was to upgrade the product. However, when air-jet yarn actually faced the market, it not only suffered a cold reception, but its own survival situation was also worrying.
In order for the market to accept an unfamiliar product, companies must be mentally prepared to share risks with users. to this end. In the way of promoting new products of air-jet yarn, our factory has chosen some honest partners. He presented them with the newly developed air-jet spinning yarn and patiently introduced the development direction of subsequent products.
The entry point for yarn development is mainly based on the introduction of Mutrata: good anti-pilling and abrasion resistance; easy to wash and quick-drying, good air permeability; good hygroscopicity and color absorption. Features include high color yield. And some functional fibers (such as Coolmax, etc.) are trial-produced on air-jet spinning. As a result, the fabrics made using this yarn are superior in function to those of the same type of ring-spun yarn.
After arduous exploration and repeated efforts. Finally, the feedback from the back-end process greatly increased people’s confidence, which is that the anti-pilling properties of air-jet spinning yarns have indeed had a significant effect on the fabric.
3 misunderstandings about air-jet yarn
During the development and promotion process, we were also troubled by another problem, that is, the air-jet yarn fabric has no weft bias. Since we simply agreed with this point of view at the beginning, this feature was particularly emphasized when promoting air-jet yarn to knitting users. However, in subsequent production practices, this view was completely rejected by many customers. What’s more, when users make certain adjustments to the process in order to improve the strength of air-jet yarns, the weft skew that appears is much more than that of similar ring-spun yarns. to this end. We have repeatedly discussed the yarn formation mechanism of air-jet yarn. After verification in actual equipment, it was finally discovered that the air-jet yarn in the actual production process has twist, and the amount of twist depends on the pressure difference between the two nozzles; this twist causes the air-jet yarn itself to have a certain internal stress. Torsion causes weft bias to appear on the knitted fabric surface: the amount of twist cannot be detected with a conventional ring yarn twist tester and can only be determined through coefficient correction.
Because the crux was found promptly and accurately. It not only avoids the possible misunderstandings of air-jet yarn products, but also provides the correct twist value for subsequent users to balance the torque when the air-jet yarn and other yarns or filaments are combined. The successful development of fabrics provides a guarantee.
4 Product introduction of air-jet yarn
Through in-depth exploration of the spinning process and yarn structure of air-jet yarn. We finally determined the general direction in which air-jet yarn can be promoted, laying the foundation for its successful entry into the market.
In addition, we have conducted a comprehensive test on the anti-pilling performance of air-jet yarn. After obtaining evaluation reports from many foreign testing agencies in Shanghai, such as Intertek (ITS), Japan Textile Inspection (JTI), and Kakon, , air-jet yarn has gradually become favored by users due to its unique anti-pilling properties. As a result, the market for air-jet yarn has finally opened.
Another characteristic of air-jet yarn is that it has a feel similar to ring-spun strongly twisted yarn. For some fiber raw materials without body bones. Such as viscose, bamboo pulp fiber, Modal, Lyocell, etc., after air-jet spinning, the appearance quality and feel of the finished yarn are very good.�Realistic imitation hemp feel.
At present, our factory has successfully developed a series of air-jet spinning products (Table 1).
In the past few years, our factory has achieved gratifying results in the production of Lyocel yarn using air-jet spinning. Backend users are also getting good returns in developing products with these yarns.
Through the development of a variety of air-jet yarns, the fiber spinning suitability of this equipment is becoming more and more understood. Currently, various types of regenerated cellulose fibers are processed on air-jet spinning equipment. At the same time, cotton, linen, silk, and wool are blended with polyester or regenerated cellulose fibers in different proportions to produce air-jet yarn. The development work is progressing smoothly, and the products can generate new ideas, which exactly meets the psychological needs of today’s people pursuing individuality AOLFZkb
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