Melt spinning is the most convenient and economic method for polymer fiber manufacturing at industrial scales. In melt spinning, the fiber-forming
substance is melted for extrusion through the spinneret and then directly
solidified by cooling. Melt spinning uses the heat to melt the polymer to a
viscosity suitable for the extrusion through the spinneret. As the name indicates
the chips of fibers are melted and extruded through the spinneret to obtain the
fibers. It is used for the polymers that are not decomposed or degraded by
temperatures necessary for extrusion. Polymer chips obtained from previously
reacted chemical combinations are melted and then pumped through a spinneret
in an air chamber. The extruded stream cool and solidify into continuous
filaments and are then drawn out of the chamber twisted and/or processed
further and subsequently wound onto spools. This method of spinning is
suitable in manufacturing the polyester yarns.
Melt spun fibers can be extruded from the spinneret in different cross-sectional
shapes (round, trilobal, pentagonal, octagonal, and others). Trilobal-shaped
fibers reflect more light and give an attractive sparkle to textiles.
Pentagonal-shaped and hollow fibers, when used in carpet, show less soil and
dirt. Octagonal-shaped fibers offer glitter-free effects. Hollow fibers trap air,
creating insulation and provide loft characteristics equal to, or better than,
down.
Steps involved in Melt Spinning
1. Feeding of the polymer to the hopper in the form of chips. The polymer chips
are feed to the extruder via hopper. These polymer chips should be free from
moisture.
2. The chips are feed to the extruder & then forced forward through the barrel
by the rotating screw. As the polymer moves forward it is softened. When it
reaches the end of the screw then the homogenized melt is filtered and guided to
spin pack.
3. Uniform feeding of molten polymers & filtration in spin block.
4. Extrusion of the molten polymer into filament.
5. Solidification of extruded molten filament by cooling media, usually air at
quench Chamber.
6. Application of spin finish.
7 Collection of filament in a suitable package
8. Post spinning operations for end use properties.
Requirements for Melt Spinning:
The polymer should not be volatile
The polymer should not decompose in the molten state and the melting
point.
Polymer should be 30 degree centigrade less than its decomposition temp.
Special Feature of Melt Spinning :
High production ( SPG. Speed 1000-2000 m/min)
Hazard, Non Toxic
No environment pollution.
No solvent required .
Heat of spg high.
Fiber Characterizations:
Different characterization methods were performed to study the resulting
fiber properties, including microstructures, thermal properties, mechanical
properties, rheological properties, molecular orientation and crystallization
behavior.
Fiber Which are Processed by Melt Spinning:
Polyester, Nylon, Olefin, Polypropylene, saran, and sulfar etc. are produced via
melt spinning process.
Advantages of Melt Spinning:
1. Can endure used for both staple together with continuous filament.
2. Direct together with elementary process.
3. No environs pollution.
4. High production speed (2500-3000) ft/min.
5. Low investment cost.
6.
Disadvantage of Melt Spinning:
1. Required to a greater extent than proper maintained of machine.
2. Heat of input is high.
-Rutuja Shinde
