Introduction to six commonly used spinning methods

The most mature process for making meltblown nonwovens and spunbonded nonwovens is spinning, which is also a common process that most manufacturers of meltblown nonwovens and spunbonded nonwovens will use. Today we Let's talk about the six common methods of spinning process in detail. 1. Gel spinning The spinning solution used is a solution, which is similar to dry spinning, but its concentration is extremely high and the solidification process is mainly cooling, which is similar to melt spinning. Sometimes accompanied by the volatilization of the solvent, the polymer is solidified into fibers, which is between the dry spinning method and the melt spinning method, also known as the semi-melt spinning method. It means that the high-concentration polymer solution or plasticized jelly is extruded from the spinning hole into the high-temperature gas atmosphere, and the filament is cooled. 2. Dry-wet spinning The filaments enter the low-temperature coagulation bath to complete the curing and molding, and the liquid crystal macromolecules are in a highly ordered frozen liquid crystal state, and the finished fiber has high strength and high modulus mechanical properties. First, it passes through a short air interlayer, where the resistance of the filaments is small, and the polymer in the liquid crystal state is beneficial to highly oriented under high stretching conditions. That is, the fiber-forming polymer is dissolved in a certain solvent to prepare a spinning solution with a suitable concentration, and then the spinning solution is spit out from the fine small holes. Dry-wet spinning is particularly suitable for the forming and processing of liquid crystal polymers, so it is often called liquid crystal spinning. It is a type of solution spinning, also known as dry jet wet spinning, which combines the characteristics of wet spinning and dry spinning. 3. Dry spinning Dry spinning requires solvent recovery and reprocessing, which is simpler than wet spinning. The mechanical properties of the fiber obtained are better than that of the wet spinning fiber of the same kind. The polymer filaments are gradually solidified, and the finished fiber can be obtained by post-processing such as stretching, setting, washing and drying. At this time, the spinning solution can be spit out from the tiny holes, into the heated gas, and the solvent in the spinning solution volatilizes. Dry spinning is a kind of solution spinning. If the fiber-forming polymer can find a solvent with low boiling point and good solubility, it can be made into spinning solution. 4. Wet spinning Wet spinning still needs a cyclic process of recovery, treatment and reapplication of the coagulation bath and post-treatment solution. The production process is complicated and the production cost is high. Finished fibers can be obtained through post-processing such as stretching, setting, washing and drying. Once the spinning solution encounters a coagulant, it coagulates and precipitates into a solid thread. It is a kind of solution spinning. The spinning solution is spit out from the tiny holes into a coagulation bath. The coagulation bath is made of high polymer The non-solvent composition of the substance. 5. Solution spinning For some polymers that have decomposed before being melted, this kind of spinning forming technology can only be selected. Solution spinning has wet spinning, dry spinning, and dry-wet spinning. In terms of spinning, obviously, the solution spinning production process is more complicated than melt spinning. After stretching, setting, washing, drying, and waiting for the treatment process, the finished fiber can be obtained, and then the spinning solution is spit out from the tiny holes into the coagulation bath or hot gas, and the polymer is precipitated into a solid thread. Solution spinning is to dissolve the fiber-forming polymer in a certain solvent to prepare a spinning solution with a suitable concentration. 6. Melt spinning Generally, all polymers that have the property of melting without decomposition, mostly use melt spinning. The melt spinning process is simple, and the spun nascent fiber only needs to be heat-set by the drawing machine to obtain the finished fiber. Melt spinning is suitable for the molding process of polymers with higher heat resistance, and the polymers should have the ability to melt and decompose. At the same time, it is stretched and thinned under the action of external force, and cooled and solidified in cold air to form fine fibers. Melt spinning is to melt the fiber-forming polymer at a temperature range above its melting temperature and below its decomposition temperature. Protruding from the tiny holes to form a trickle of melt. The above is the detailed content of the introduction of the six commonly used spinning methods. If you don't understand, you can directly contact the relevant personnel of Fujian Nonwovens Co., Ltd.