In recent years, regenerated cellulose fibers (such as viscose, modal, Tencel and other fibers) have been emerging continuously, which not only meet people's needs in a timely manner, but also partially alleviate the problems of resource scarcity and natural environment destruction.
Because regenerated cellulose fiber has the advantages of natural cellulose fiber and synthetic fiber, it is widely used in textile with an unprecedented scale of use.
01.Ordinary viscose fiber
Viscose fiber is the full name of viscose fiber. It is a cellulose fiber obtained by extracting and remodeling fiber molecules from natural wood cellulose with "wood" as raw material.
Preparation method: plant cellulose is alkalized to form alkali cellulose, and then reacts with carbon disulfide to form cellulose xanthate. The viscous solution obtained by dissolving in dilute alkaline solution is called viscose. Viscose is formed into viscose fiber after wet spinning and a series of processing procedures
The non-uniformity of the complex molding process of ordinary viscose fiber will make the cross-section of conventional viscose fiber appear waist round or irregular, with holes inside and irregular grooves in the longitudinal direction. Viscose has excellent moisture absorption and dyeability, but its modulus and strength are low, especially its wet strength is low.
Modal fiber is the trade name of high wet modulus viscose fiber. The difference between modal fiber and ordinary viscose fiber is that modal fiber improves the disadvantages of low strength and low modulus of ordinary viscose fiber in wet state, and also has high strength and modulus in wet state, so it is often called high wet modulus viscose fiber.
Similar products of different fiber manufacturers also have different names, such as Lenzing modal TM brand fiber, polynosic fiber, Fuqiang fiber, hukapok and newal brand name of lanzing company in Austria.
Preparation method： The high wet modulus is obtained by the special process of the production process. Different from the general viscose fiber production process:
(1) Cellulose should have a high average degree of polymerization (about 450).
(2) The prepared spinning stock solution has a high concentration.
(3) The appropriate composition of coagulation bath (such as increasing the content of zinc sulfate in it) is prepared, and the temperature of coagulation bath is reduced to delay the forming speed, which is conducive to obtaining fibers with compact structure and high crystallinity. The inner and outer layer structures of the fibers obtained in this way are relatively uniform. The skin core layer structure of the cross-section of the fibers is not as obvious as that of ordinary viscose fibers. The cross-sectional shape tends to be circular or waist circular, and the longitudinal surface is relatively smooth. The fibers have high strength and modulus in the wet state, and excellent hygroscopic properties are also suitable for underwear.
The structure of the inner and outer layers of the fiber is relatively uniform. The structure of the skin core layer of the fiber cross-section is less obvious than that of the ordinary viscose fiber. The cross-sectional shape tends to be round or waist round, and the longitudinal direction is relatively smooth. It has high strength and modulus in wet state and excellent moisture absorption performance.
Lyocell fiber is a kind of artificial cellulose fiber, which is made of natural cellulose polymer. It was invented by the British kautor company and later transferred to the Swiss Lanjing company. The trade name is Tencel, and its homonym "Tiansi" is adopted in China.
Preparation method: Lyocell is a new type of cellulose fiber prepared by directly dissolving cellulose pulp into a spinning solution with n-methylmoline oxide (NMMO) aqueous solution as a solvent, then using wet spinning or dry wet spinning method, using a certain concentration of nmmo-h2o solution as a coagulation bath to form the fiber, and then stretching, washing, oiling and drying the spun primary fiber.
Compared with the conventional viscose fiber production method, the biggest advantage of this spinning method is that NMMO can directly dissolve cellulose pulp, the production process of spinning stock can be greatly simplified, and the recovery rate of NMMO can reach more than 99%, and the production process hardly pollutes the environment.
The morphological structure of Lyocell fiber is completely different from that of ordinary viscose. The cross-sectional structure is uniform, round, and there is no skin core layer. The longitudinal surface is smooth and no groove. It has superior mechanical properties than viscose fiber, good washing dimensional stability (shrinkage rate is only 2%) and high moisture absorption. It has beautiful luster, soft handle, good drapability and good elegance.
The difference between viscose, modal and lessel
(1) Fiber section
(2) Fiber characteristics
• Viscose fiber
• It has good moisture absorption and meets the physiological requirements of human skin. The fabric is soft, smooth, breathable, not prone to static electricity, UV resistant, comfortable to wear, easy to dye, bright color after dyeing, good color fastness, and good spinnability. The wet modulus is low, the shrinkage rate is high and it is easy to deform. The hand feels hard after launching, and the elasticity and wear resistance are poor.
• Modal fiber
• It has soft touch, bright and clean, bright color and good color fastness. The fabric feels especially smooth, the cloth surface is bright and lustrous, and the drapability is better than the existing cotton, polyester and viscose fibers. It has the strength and toughness of synthetic fibers, and has the luster and feel of silk. The fabric has wrinkle resistance and ironing resistance, good water absorption and air permeability, but the fabric is poor.
• Lessel fiber
• It has many excellent properties of natural fiber and synthetic fiber, natural luster, smooth feel, high strength, basically no shrinkage, good moisture permeability and permeability, soft, comfortable, smooth and cool, good drapability, durable and durable.
(3) Scope of application
• Viscose fiber
• Short fibers can be pure spun or blended with other textile fibers, which are suitable for making underwear, outerwear and various decorative articles. The filament fabric is light and thin, and can be used for quilt and decorative fabrics in addition to clothes.
• Modal fiber
• Modale's knitted fabrics are mainly used for making underwear, but also for sportswear, casual wear, shirts, high-end ready-made fabrics, etc. Blending with other fibers can improve the poor straightness of pure modal products
• Lessel fiber
• It covers all fields of textile, whether it is cotton, wool, silk, hemp products, or knitting or weaving, it can produce high-quality and high-end products.
(Article adapted from: fabric course)
Post time: Aug-22-2022