Due to the reduction of cultivated land area and the increasing depletion of natural fibers in petroleum resources, the output of synthetic fibers will be increasingly restricted; while people pay attention to the environmental protection performance of textiles in the consumption process, they have also begun to pay attention to the value of regenerated fibers. Rediscover and rediscover. Today, the application of regenerated fibers has gained unprecedented development opportunities. In order to overcome the complex process, large investment and heavy pollution of regenerated fiber, through continuous research on the representative “Tencel”, the fiber has been developed in large quantities!
The concept of Tencel fiber
“Tencel fiber” is a new type of man-made cellulose fiber. The International Man-made Fibers Bureau named it in 1989 for “LYOCELL”. It comes from cellulose in trees and is completed under physical action by using an organic solvent (NMMO) spinning process. The entire manufacturing process is non-toxic and pollution-free. Therefore, “Tencel” is known as “the green fiber of the 21st century”.
The structure and performance of Tencel fiber
The cross-section of Tencel fiber is circular, with a uniform structure and no obvious core. Structure, fiber surface is smooth.
Performances of Tencel fiber
The crystallinity and orientation of Tencel fiber are higher than ordinary High viscose fiber
Polymerization degree of Tencel fiber
The degree of polymerization indicates the size of the molecules in the polymer. The degree of polymerization of Tencel fiber The degree of polymerization is relatively high, very similar to that of raw pulp, as shown below.
In general, as the degree of polymerization increases, the fiber has the following properties:
The fiber orientation and crystallinity are improved, and the fiber has high strength and low elongation properties. The fiber’s alkali resistance improves the fiber nodule strength and elastic modulus. As the degree of fiber polymerization increases, the adaptability of textile processing, fabric dimensional stability, and washability also increase accordingly, and the adaptability as a clothing fabric also expands.
★Mechanical properties
The breaking strength of Tencel fiber is equivalent to the relative strength of polyester fiber, which is much greater than cotton and viscose fiber. It can Withstands vigorous handling and water treatment without damaging fabric quality. The degree of polymerization is almost twice that of ordinary viscose fiber.
★Initial modulus
The modulus of ordinary fiber in the dry state is about 70cN/ tex, while the initial modulus of Tencel fiber is almost several times that, which is related to the degree of orientation and crystallinity in the fiber. Tencel fiber can still maintain a high modulus value when wet, which is very important in textile processing because it can ensure that the fiber has good shape retention when it is processed under wet or wet conditions.
★Hygroscopic properties
As can be seen from the above table, its lateral swelling rate can reach 40%, and The longitudinal direction is only 0.03%. In the table, Tencel has the largest transverse swelling rate, the smallest longitudinal swelling rate, and the largest anisotropy ratio. Such a high transverse swelling rate will bring some difficulties to the wet processing of the fabric, which is also a difficulty in Tencel fiber processing. However, it has the characteristic of high transverse swelling rate, which can make the fabric during wet processing obtain good softness. At the same time, because Tencel fiber has a higher modulus value, it will also bring greater deformation recovery force, so it will not have the defects of viscose fabrics that are not stiff and easy to wrinkle.
★Dyeability
Because Tencel fiber is still a cellulose fiber, its dyeing performance should be the same as that of cotton fiber and viscose fiber, but In contrast, dyes suitable for viscose fiber should be more suitable for it. Direct dyes, reactive dyes, vat dyes, sulfur dyes and Naftol dyes can all be used. However, considering the aspects of hue, vividness, color fastness and ease of dyeing operation, reactive dyes are more effective.
★Characteristics of original chemical fiber
The main performance of original chemical fiber is that the fiber can peel off finer microfibers layer by layer along the longitudinal direction. This is the original chemical fiber. A structural feature unique to the fiber structure. Tencel fiber has relatively high crystallinity and orientation, and the giant fibrils formed by the direct aggregation of macromolecules into basic fibrils are basically arranged along the longitudinal direction of the fiber. Therefore, it is easier to peel off layer by layer along the longitudinal direction of the fiber, so after this fiber is subjected to external mechanical force, its finer fibers will be peeled off from the fiber. Increasing the mechanical processing force, processing under high temperature and alkaline pH conditions, using low-twist yarns and loose-structured fabric structures, etc., will enhance its original chemical fiber effect.
From a practical effect point of view, fibers that are easy to proliferate into chemical fibers can bring a fluffy effect to the fabric style and improve the feel. From a processing perspectiveIt is very important to even out the tension, and a single yarn tension meter can be used to check and adjust the full-width tension. Use spring pressure to prevent the yarn from coming out from under the tension plate.
2. Small jacquards with unclear openings. Due to the large number of heald frames, it is easy to cause unclear openings and more small skipping patterns. It can be considered to add liquid wax to the refrigerant on the warping beam to further reduce the friction coefficient of the yarn, improve the slipperiness of the yarn, and improve the phenomenon of unclear weaving openings.
3. Use dividing rods to prevent adhesion. For individual varieties with larger warp density, hairiness and hair particles will become more and more due to repeated friction between yarns during the weaving process, and the back shuttle will Mouth tends to stick together. Plain grain dividing rods can be used to prevent adhesion, which is very effective. At the same time, parameters such as opening angle, back beam height, and weaving tension are reasonably configured to ensure green quality.
4. Performance analysis of Tencel fabric Through the analysis of the weaving process of Tencel fabric, we know how to improve the wearing performance of the fabric. Here, some typical cotton-type Tencel fabrics are selected for experimental testing. Through the analysis of test data, the wearing and processing properties of Tencel fabrics are further studied to provide a reference basis for the specification design and production and processing process control of this type of fabrics to meet the needs of consumers. The users have different requirements for Tencel fabrics.
Precautions for using Tencel fabric
Through the test and analysis of the basic properties of Tencel fabric, it can be concluded that when designing and using Tencel fabric for clothing The following issues must be paid attention to:
(1) Tencel fabrics with different specifications and warp and weft combinations have greatly different wearing properties, and great attention should be paid to them during design in order to determine a reasonable production process route and specific details. machine technology.
(2) Tencel fabric has characteristics similar to natural fibers and better comfort. When designing fabrics for clothing, the requirements for clothing shape must be considered, as well as the bending resistance, wrinkle resistance, and shrinkage of the fabric. Performance is analyzed and controlled. For example, the warp and weft bending stiffness of the fabric has a certain influence on the shape of the clothing. When designing varieties and selecting fabrics, the bending stiffness of the fabric must be higher than 5uN·m, and the difference in the bending stiffness in the warp and weft directions cannot be too large.
(3) Tencel fiber has high hygroscopicity, and the thermal moisture shrinkage rate of the fabric is relatively high. Therefore, shrinkage is easy to occur during fabric finishing and garment ironing. In designing the fabric machine process and When using fabrics, you should grasp the relevant specifications and dimensions, and take into account the impact of differences in yarn shrinkage caused by fibers with different shrinkage rates on the finishing and appearance of the fabric. </p
