Meltblown nonwovens and
spunbond nonwovens making the most mature process is the spinning process, which is the vast majority of meltblown nonwovens and spunbond nonwovens manufacturers will use a common process, today we To talk about the spinning process in detail six common methods.
1. Jelly spinning
The spinning solution used is a solution, which is similar to dry spinning but at a very high concentration and the curing process is mainly cooling and again similar to melt spinning. Sometimes accompanied by solvent evaporation, then the polymer solidified into fibers, bound in the dry spinning method and the melt spinning method, also known as semi-melt spinning method. Refers to the high concentration of polymer solution or plasticized jelly extruded from the spinneret hole into the high temperature gas atmosphere, the wire is cooled.
2. wet and dry spinning
The filaments then enter the coagulation bath at low temperature to complete the curing molding, and the liquid crystal macromolecules are in a highly ordered frozen liquid crystal state. The prepared finished fibers have high strength and high modulus mechanical properties. First, after a short period of air sandwich, where the resistance of the filaments is small, the polymer in the liquid crystal state is advantageous for high orientation under high stretching conditions. The fiber-forming polymer is dissolved in a solvent to prepare a spinning solution having a suitable concentration, and then the spinning solution is discharged from the fine holes.
Wet and dry spinning is particularly suitable for liquid crystal polymer molding process, it is often called liquid crystal spinning. Is a kind of solution spinning, also known as dry jet wet spinning method, which combines wet spinning and dry spinning characteristics.
3. dry spinning
Dry spinning requires solvent recycling and reprocessing cycles that are simpler than the wet spinning process. The obtained fiber has better mechanical properties than similar wet-spun fibers.
Polymer filaments gradually solidified by stretching and setting drying process can be obtained after drying fiber products. In this case, the spinning solution can be discharged from the fine holes into the heated gas and the solvent in the spinning solution is volatilized. Dry spinning is a kind of solution spinning, if the fiber-forming polymer can be found in a lower boiling point, good solubility of the solvent made of spinning solution.
4. wet spinning
Wet spinning still requires coagulation bath and post-treatment solution recovery, processing and re-application of the recycling process, the production process is complex, higher production costs.
After stretching - setting - washing - drying and other post-treatment process can be finished fiber. Once the spinning solution is coagulated, it is coagulated and precipitated into a solid yarn, which is one kind of solution spinning. The spinning solution is spit out from the fine holes into a coagulation bath made of high poly Non-solvent composition of matter.
5. solution spinning
For some polymers that have not been melted and decomposed, we can only choose this kind of spinning and forming technology. There are also wet spinning, dry spinning, wet spinning and wet spinning in solution spinning, Obviously, the solution spinning process is more complicated than melt spinning.
After stretching - setting - washing - drying process can wait to get the finished fiber, and then the spinning solution spit from the tiny holes into the coagulation bath or hot gas, the polymer precipitated into solid filaments . Solution spinning is to dissolve the fiber-forming polymer in a solvent to prepare a spinning solution with suitable concentration.
6. Melt spinning
Generally, any polymer with melting and non-decomposing properties is mostly melt-spun. Melt spinning process is simple, after spinning the nascent fiber only need to stretch machine after heat-setting to obtain the finished fiber. Melt spinning suitable for high heat-resistant polymer molding process, the polymer should have the melting and decomposition performance.
At the same time under the action of external force stretching thinning, and cooling in the cold air curing, the formation of fine fibrous material. Melt spinning is the temperature at which the fiber-forming polymer melt is above its melting temperature and below the decomposition temperature. From the tiny holes protruding to form a melt stream.
The above is our finishing on the six spinning methods introduced in detail, if you want more about nonwovens, please click
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