Lyocell fiber (that is, soluble fiber) was called green fiber in 2 1 century. It is a regenerated cellulose fiber by wet spinning with N- methylmorpholine -N- nutrient (NMMO) as solvent. Waste can be naturally degraded, and 99.5% of amine oxide solvent can be recycled in the production process. "Very low toxicity, no environmental pollution". 1980 was first patented by Akzo-Nobel Company in Germany, and 1989 was officially named by the International Commission on Man-made Fibers and Synthetic Fibers. At present, the global production capacity is about 6.5438+0.2 million tons, which are distributed in the United States, Britain, Austria, Germany, India, South Korea and Taiwan Province Province of China. Lyocell fiber is used in clothing because of its excellent wearability. It can be spun pure or blended with cotton, hemp, silk, wool, synthetic fiber and viscose fiber to improve the performance of other fibers. The fabric woven with its yarn is glossy, soft and smooth, natural in hand feel, good in drape, good in air permeability and comfortable to wear. Pure lyocell fabric has pearl luster, and its inherent fluidity makes it look light and drape well. Through different textile and knitting processes, pure Lyocell fabrics and blended fabrics with different styles can be woven for high-end jeans, ladies' underwear, fashion, men's high-end shirts, casual wear, casual wear and so on. The newly developed fine denier and ultra-fine denier lyocell fibers make it play a better role in the development of high-grade products. At present, Lyocell products are becoming more and more popular in Japan, Western Europe and the United States, and the sales volume is increasing. B In industrial application, Lyocell fiber has high strength, the dry strength is close to polyester fiber, much higher than cotton, and the wet strength is almost 90% of the dry strength, which is incomparable to other cellulose fibers. It has been widely used in nonwovens, industrial filter cloth, industrial silk and special paper. Lyocell fiber can be made into nonwovens with various properties by needling, spunlace, wet-laying, dry-laying and thermal bonding, and its properties are better than viscose fiber products. Several European companies are studying the application of lyocell fiber in sewing thread, work clothes, protective clothing, diapers, medical clothing and so on. Japanese paper mills are also developing the application of lyocell fiber in specialty paper.
Lyocell fiber products will produce obvious fibrillation under the friction of mechanical external force in wet state, which shows that fine fibrils and hairiness are separated longitudinally on the yarn surface. The reason of fibrillation is the high axial orientation of Lyocell fibers and the weak transverse bonding force between microfibers. The high expansion of fibers in wet state further weakens this binding force, which makes the fibers fall off under the friction of themselves or metals, and the remaining cortical fibers crack longitudinally, forming long and uneven fibril fluff. Lyocell's fibrillation characteristics make this fiber fabric have two kinds of finished products, one is to use fibrils.
Fibrillation characteristics, through primary fibrillation, enzyme treatment, secondary fibrillation, peach skin style products are produced, and the other is that after enzyme treatment, objects with smooth surfaces are produced without secondary fibrillation. Lyocell fiber is easy to fibrillate, which brings convenience to the production of non-woven fabrics, filter materials and peach skin style fabrics, but it brings trouble to the production and use of smooth fabrics, such as the control of processing technology, the selection of equipment and additives in production; In the process of use, the fabric is easy to pilling and the color light will also change. In addition, the clothes made of Lyocell fabrics have a strong sense of obsolescence due to the serious fibrillation after repeated daily washing.
Properties of lyocell fiber
Lyocell fiber is mainly composed of cellulose, such as cotton or viscose fiber. Its molecular weight and crystallinity are between cotton and viscose.
Polymerization degree and crystallinity of lyocell fiber, cotton and viscose fiber
Fiber cotton lyocell fiber viscose
Degree of polymerization 10000 500-550 250-300
Crystallinity (%) 70 50 30
References:
1. Fibrillation of Zhang Yongxia Lyocell Fiber Fabric, 2005,3.
/view/509847.htm