Wet spun primary fibers are in swelling state due to a large amount of liquid. Macromolecules have great activity and low orientation. Their morphology and structure are closely related to spinning conditions. By selecting and controlling the spinning conditions, the fibers with different cross section shape or special pore structure and special properties can be made There are different forms of wet spinning and different structures of spinning machines. For example, there are single bath method or double bath method, deep bath method or shallow bath method, funnel forming or tube forming, etc.
The winding device of the wet filament spinning machine is centrifugal can type or bobbin type. In short fiber spinning, the post-treatment machine is usually used. The primary fibers formed at each spinning part are assembled into bundles and processed continuously.
Wet spinning requires not only a wide range of raw solution preparation and pre spinning preparation equipment, but also coagulation bath, circulation and recovery equipment. The process flow is complex, the investment cost of plant building and equipment is large, and the spinning speed is low, so the cost is high. Tens of thousands of holes of spinneret or cartridge spinneret can be used to improve the production capacity. Generally, only synthetic fibers that cannot be spun by melt, such as polyacrylonitrile and polyvinyl alcohol fibers, are suitable for wet spinning with polymer solution to produce segmented fibers and long tow.