The mechanism and evaluation method of fabric pilling

1. The mechanism of pilling The so-called fabric pilling refers to the formation of hairs from one or several fibers on the surface of the fabric, which are then entangled in a spherical state. When hooked filaments are generated on the surface of the filament fabric, one or several hooked monofilaments are entangled into a ball. These hair balls not only affect the appearance, but also become the reason for the decline in style such as feel. For the phenomenon of pilling, knitted fabrics with a loose structure are most likely to occur. According to research and observation, during the process of taking, the natural fibers of the fabric are first pulled out to form a ring and hairy by external friction. The condition for the hair to be pulled out must be that the external force is greater than the friction of the fiber on the yarn. Therefore, short-fiber fabrics with strong twisted yarns or fibers with a large friction coefficient have greater resistance to fuzzing and are not easy to fuzz. After the fur reaches a certain length, it can be rectified and formed into a ball. Therefore, the length of the fur being pulled out has a great influence on the pilling of the fabric. In addition, the factors of pilling are the bending resistance, strength and wear resistance of the fiber. Fibers that are easy to bend are easily entangled into balls during friction, and the shedding of hair balls depends to a large extent on the strength and wear resistance of the fibers. Some fibers have been frayed or pulled off before forming longer fluffs, leaving only very short fluffs, which is not easy to form balls. If the strength of the fiber's bending resistance and abrasion resistance is weak, the hair balls on the surface of the fabric will soon fall off as the friction continues. As mentioned above, the formation of pilling can generally be divided into three stages; namely, the occurrence of hair, the formation of hair balls and the shedding of hair balls. Since the premise of pilling is the production of hair, in addition to selecting suitable fiber raw materials and yarn processing conditions to make it difficult to extract the fibers from the fabric, the fabric's resin theory can also improve the anti-pilling effect. However, this method will cause a hard feel, so it is an ideal method to make the hair fall off before the hair ball is formed. If the fiber is modified to reduce the fiber strength, it will fall off after being rubbed and will not easily become a ball. 2. Evaluation of fabric pilling For fabrics, it is most reasonable to evaluate the pilling resistance by the pilling density after being subjected to friction, that is, the number of hair balls per unit area. However, because the size and shape of the puck are uncertain, if they are counted equally, the overall impression of the pilling fabric cannot be obtained. Therefore, the main method to measure the degree of pilling of the fabric is to compare the pilled fabric with the standard sample to determine the degree of pilling of the sample. The domestic rating adopts a five-level system. The smaller the number, the more serious the pilling of the fabric. On the contrary, the better the anti-pilling performance. When the sample is graded, there is a half-level one gear between each level as needed. As for the specific assessment, there are two methods: eye rating and instrument rating. The rating method described in L only considers the form of pilling, and does not consider the process after reaching the maximum pilling degree, which is a defect.