What is melt spinning?
In the melt spinning method, the polymers are melted to form the viscosity which is suitable for extrusion. The polymers which do not get decomposed or degraded by the temperatures necessary for extrusion use a melt spinning method. Most of the filament yarns are manufactured using a melt spinning method. Since there is no solvent used, hence the purification stage is eliminated.
In this method, at first the polymer is heated until it melts to form liquid solution suitable for spinning. Then the molten polymers are fed to the heated hopper. Through the sieve and filter the molten liquid is purified. Through the spinneret, the molten polymer is extruded at high pressure and constant rate. The filaments are then directly solidified by putting them into a relatively cooler air stream. After solidifying, the filament yarns are wound onto bobbins or treated further to achieve desired characteristics. This process is used for manufacturing filament yarns of polyester, nylon, olefin, saran and glass fibers.
Through melt spinning, the filaments can be extruded into various shapes such as round, trilobal, pentagonal, octagonal, and others. Trilobal shapes are used to provide the fiber with attractive sparkle as they reflect more light. Hollow and pentagonal shaped yarns are used in making carpets as they soil less and create insulation.