From the flocking point of view, the most commonly used fluff are viscose and nylon fibers. Viscose fiber is made from wood as raw material through certain chemical processing. The crystalline area of the fiber is 30~40%, and the degree of polymerization is about 250~500. Because the crystalline area of viscose fiber is high, the dye is not easy to penetrate. Generally, it is difficult to obtain good blackness when dyeing black, and special dyes and dyeing methods must be used. At the same time, due to its low degree of polymerization, the fiber strength is far less than that of nylon. Generally, the dyes suitable for viscose fibers are direct, reactive, vulcanized, etc. Naphto is also available, but it is rarely used. The viscose does not soften or melt at high temperature, and begins to discolor and decompose at 260~300℃.
Nylon fiber is a polymer material connected by organic diacid and diamine amino acid or acrylamide as raw materials through amide bonds. Nylon fiber has good elasticity, high strength, wear resistance and durability. It is a thermoplastic fiber, commonly used nylon 6 , Nylon 66. Nylon fiber has good elasticity and luster, but nylon 66 turns yellow at 150°C, becomes sticky and softens at 230°C, and melts at 250°C; while nylon 6 softens at 180°C and melts at 215°C. Therefore, in the process of dyeing wool, flocking and printing, it is necessary to first find out what kind of fiber it is, so that the dye and process can be correctly selected according to its performance, so as not to cause unnecessary losses in the processing process.