The process of spinning by which fiber or filament is produced from melted polymer chips by extruding through spinneret continuous filament produced here. The number of filament depends on number of holes in spinneret. It is the most critical operation is the production of nylon, polyester, and polyolefin, polypropylene fibers as a number of fibre properties such as uniformity, crystallinity, and orientation are imparted to the yarn during processing. A flowchart of the melt spinning process is given below.
Process Flow Chart of Melt Spinning
Feeding (Polymer chips)
Cooling and solidification by cold air
Spinning process: Melt spinning uses heat to melt the polymer to a viscosity suitable for extrusion. This type of spinning is used for polymers that are not decomposed or degraded by the temperatures necessary for extrusion. This method is used by 70% of the fibers.
Melt spinning is the most economical process of spinning due to the fact that no solvent is recovered or evaporated just like in solution spinning, and the spinning rate is fairly high. It is the preferred method of fabricating polymeric fibers and is used extensively in the textile industry.
Melt spinning, the polymer is heated and it melts to form a liquid spinning solution or dope. Chips of polymers are fed to a hopper which is heated. There is a grid (sieve) at the base which permits only molten liquid to pass through. Then the solution is purified by filter. The molten polymer is extruded at high pressure and constant rate through a spinneret into a relatively cooler air stream that solidifies the filaments. Finally, the filament yarn either is immediately wound onto bobbins or is further treated for certain desired characteristics or end-use.
Example: Melt spinning is used for the production of polyester, nylon, olefin, saran, and other glass fibers.
Advantages: High speed (275 to 1500 yds /min), No solvents, No purification problems.
Disadvantages: Separate drawing step.
Author of this Article: Muhammad Ibrahim Khalilullah Department of Textile Engineering Daffodil International University Email: [email protected]