Views:176 Author:Site Editor Publish Time: 2019-07-17 Origin:Site
Nylon 6 and Nylon 66, the two kinds of filament be used mostly in recent silk industry. The Nylon filament includes pre-oriented yarn (POY) and fully drawn yarn (FDY), and silk factory almost chooses FDY.
The main difference of POY nylon filament and FDY nylon filament is the different tensile strength. Tensile is the process of gathering and stretching a bunch of filament by twisting and tensiling machine, which will change macromolecular arrangement in the fiber and make molecular array in order, which is named orientation. Fibers with different strength and elongation can be made by changing the drawing ratio. In the manufacture of chemical fibers, a smaller draw ratio is used to make the orientation degree lower. Pre-oriented yarn (POY) is a kind of yarn with insufficient drafting ratio. Its feature is elongation. While FDY filament belongs to drawing filament. Compared with POY nylon filament, FDY filament has lower elongation and higher strength.
An experimental study shows that the elongation of POY nylon filament is much greater than that of FDY filament, and the color absorption is better than FDY filament, but the boiling water shrinkage rate is higher. FDY filaments with different strength and elongation ratios have different color absorption and boiling water shrinkage. Due to the high elongation of POY Nylon Yarn, people are worried that it will cause uneven tension in various weaving processes, resulting in defects such as color difference and color shift of finished products. But in fact, as long as the tension is strictly controlled (generally the tension on the machine is controlled at about 29 cN), there will be no defects such as broken ends and wool due to the uneven tension of monofilament, and the finished products will be dyed fairly evenly.
Because POY system has higher elongation than FDY filament, and the utilization rate of raw materials is also high. The warp length of nylon belly fragrance grade 77.8 DT warp is 540 m after changing to POY 56.dt warp. The former is about 50 m longer than the latter. The warp length of crepe is 920 m, and the length of the machine can reach 905 m or so after changing the warp length of nylon belly fragrance grade 77.8 DT warp into POY 56.dt warp. Therefore, POY Nylon Yarn saves more raw materials than PDY yarn. In actual production, POY Nylon Yarn is used as warp raw material of crepe and Fuxiang grade. It is suitable to control the tension between 15 and 17 cN. Therefore, the shrinkage of POY Nylon Yarn is larger. If the variety is simple, the tension of POY Nylon Yarn can be increased, so the shrinkage can be reduced and the raw material can be saved more.
Through continuous research and trial, we have also improved the quality of materials and increased their functions. As we know, the situation of pre-spinning elongation roller and winch roller often occurs in the production of silk yarn with purchased cotton balls, which seriously affects the output and quality, and also causes waste of raw materials. The main reason is the improper filling of oil to wet and wrapped yarn in the production of cotton balls, which shows that the cotton ball return period is half low and the static electricity is serious in the pre-spinning process. The wetting rate of cotton ball is improved by using wet liquid, and the conductivity, softness and lubricity of the fibers are also increased.
POY nylon filaments are more used in the manufacture of chemical fibers, owing to its excellent function and resource-saving features.