Modal fiber is a regenerated cellulose fiber with high breaking strength and high wet modulus. The raw material of the fiber is wood pulp and is processed into fiber by special spinning process. All the raw materials of the product are natural materials, harmless to human body, and can be naturally decomposed and harmless to the environment. Its dry strength is close to that of polyester, and its wet strength is much higher than that of ordinary viscose. Its luster, softness, moisture absorption, dyeing and dyeing fastness are superior to those of pure cotton products. The fabrics made from it show a silk luster with pleasant soft touch, drape and excellent wear resistance.
At present, the main products on the market are LENZING MODAL & mdash; & mdash; & mdash; & Lanjing Modal produced by Austrian LENZING Company; FormOTEX & mdash produced by Taiwan Chemical Fiber Co., Ltd. & mdash; & Taihua Modal. Others are BILRA MADAL produced by THAI RAYON, Thailand, BILRA MADAL MICRO and BILRA MADAL MICRO produced by GRASIM, India. Due to different production processes, the surface characteristics of modal fibers produced by different companies are also slightly different.
Lesser Fiber is the commercial name of regenerated cellulose fibers produced by COUR TAULDS Company in Britain, commonly known as & ldquo; Tencel & rdquo; (Tencel) fibers. Lesel fiber is known as the environmental protection fiber in twenty-first Century. It is mainly coniferous wood pulp, water and solvent oxidized amine mixed heating to complete dissolution, in the dissolution process will not produce any derivatives and chemical effects, through impurity removal and direct spinning, its molecular structure is simple carbohydrates. Its production process does not pollute the environment and does not destroy the ecology.
the way to distinguish
The author has been engaged in fiber identification for a long time, and has accumulated some experience. The characteristics and identification methods of Lanjing Modal, Taihua Modal and Lesser fibers are briefly introduced below.
Microscopical method
Lanjing Modal occupies most of China's market. It is an Austrian company, LENZING, which uses European beech to make wood pulp, and then uses special spinning process to make fibers. Microscopically, the cross section of Lanjing Modal is dumbbell-shaped with no cavity. See Fig. 1. The surface of the longitudinal section is smooth with 1-2 grooves. See Fig. 2.
Taihua Modal is a kind of wood pulp fiber produced by Taiwan Chemical Fiber Co., Ltd. Its cross-section is close to circular and has no cavity. See Figure 3. Its longitudinal section surface is smooth, and some have intermittent and inconspicuous vertical lines, as shown in Figure 4.
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Under the microscope, the cross section of Lesser fibers is irregular and circular, with no cavity. See Fig. 5. The surface of the longitudinal section is smooth, and some of them have intermittent and inconspicuous vertical lines. See Fig. 6.
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To sum up, according to microscope method, we can distinguish Lan Jing modle. The cross-section of modal and Lesel is the closest to the vertical section or the cross section. As can be seen from the longitudinal section pictures, although Taihua Modal is as smooth as Lesser's cylinder when water is used as medium, its diameter is relatively large and it is not as lustrous as Lesser's, and sometimes the intermittent and inconspicuous stripes shown in the picture above can be seen. When nitric acid is used as medium, swelling occurs in both Taihua Modal and Lesser. The longitudinal section of Taihua Modal changes to a flat strip shape, and its luster decreases. Lesel just grew bigger or shiny. Another point is that Lesser is not all smooth cylinders, there will be concave and convex knots as shown above, and sometimes points like vesicles can be observed.
Combustion method
When the Modal and Lesser fibers touch the flame, they are instantly burned, smelling of paper, and the residues are soft flocculent ashes. Normally they can not be distinguished by the smell of burning through the nose.
Cellulosic fibers that burn poorly will have ashes. According to the data and experience, light metal salts present slightly white ash, while heavy metal oxides present black. The raw material of the platform is very broad and mixed, and its ashes will be black and gray. The pulp of Orchin Modal comes from beech trees of about 10 years old in Austria. Lesser is mainly coniferous wood pulp, which contains a lot of minerals. Its ash tends to be slightly black, but the difference is very slight. Moreover, the ash will be affected by the residue of reagent used for finishing, and it is difficult to accurately determine by naked eyes alone.
The raw material of Lesser fibers is wood pulp, which is dissolved in organic solvent of organic amine oxides in the process of manufacture. As a result, the impurity content of Lesser fibers is lower and the combustion is more full than that of Modal fibers. When burning, Mars will continue to fly out, and only a small amount of ashes will be left after burning. This dust flying phenomenon is peculiar to Lesel fibers.
Dissolving method
A small amount of Lanjing Modal, Taihua Modal and Lesser fibers were selected to compare their dissolution, as shown in Table 1.
Table 1 fibrinolysis tables of modal, modal and Lesel
According to the above table, the longer the dissolution time between Modal and Lesser, the more obvious the difference is - mdash; - mdash; Lesser is more insoluble. At room temperature, modal is at 59..5% sulfuric acid and 37% hydrochloric acid reagents have been dissolved after 5min treatment. The same is true at 70 C formic acid / zinc chloride reagent. But Lesel is still jelly, which is relatively hard to dissolve. Therefore, when making quantitative analysis, Lesser blended fabrics should decide whether it is necessary to prolong the dissolution time or raise the temperature according to the actual situation.
conclusion
Through microscopic observation, Lanjing Modal can be distinguished. Taihua Modal and Lesser can make a preliminary judgment by observing whether there is ash flying during combustion, and then observe the diameter and luster of the fibers through microscopy. Then, they can make a final judgment by observing the degree of difficulty of dissolution through dissolution method, so as to qualitatively analyze the three kinds. Fiber. However, due to the similar chemical composition of regenerated cellulose fibers, chemical methods can not be used for quantitative analysis.
