Introducing the spinning methods of chemical fibers

Introducing the spinning methods of chemical fibers

According to the different properties of the high-polymer forming fibers, the spinning methods of chemical fibers mainly include two major categories: melt spinning method and solution spinning method. In addition, there are special or unconventional spinning methods. In the production of chemical fibers, most of them adopt the melt spinning method for production, followed by wet spinning production, and only a small number adopt dry spinning or other unconventional spinning methods for production.

Melt spinning method, also known as melt spinning, is abbreviated as melt spinning. After pre-crystallization and drying, the fiber-forming polymer chips are added from the polymer hopper, melted, mixed, metered, and extruded through the screw extruder. After extrusion, they are sent to the melt metering pump through the bend pipe between the spinning boxes. The melt is quantitatively extruded from the small holes of the spinneret through the metering pump located in the spinning box to form melt filaments. The melt filaments enter the spinning process and are cooled and solidified in a low-temperature and cooling air environment, forming primary fibers. The primary fibers are then oiled, networked, and wound into bobbins. After subsequent secondary forming processes such as stretching and heat setting, the finished fibers with applicability are obtained.

Melt spinning method is further divided into direct spinning method and chip spinning method according to the preparation process of the melt. The process of directly feeding the polymer melt after polymerization into a metering pump for metering and extrusion spinning is called the direct spinning method; while the technology of spinning the polymer chips after necessary pre-spinning preparation such as pre-crystallization and drying through a screw extruder is called the chip spinning method.

On a large-scale industrial production, direct spinning technology is often used, which is beneficial for reducing production costs, but it is difficult to produce differentiated fiber varieties, and only slight changes can be made in linear density and fiber cross-sectional shape. The chip spinning method is more flexible, easy to change varieties, and suitable for producing small batches of high-value differentiated fibers.