Published 1997 · Materials Science
As stated in the previous chapter, melt-spinning is the simplest method of fibre manufacture, mainly because it does not involve problems associated with the use of solvents. It is therefore the preferred method, provided the polymer gives a stable melt. When polymer granules or chips form the starting material for melt-spinning, they are first dried and then melted in the extruder. The homogenized and filtered melt is squirted through narrow channels into a quench chamber where solidification of the fluid filament bundles is achieved (Fig. 4.1). Finally, spin finish is applied before the filament bundles are wound on tube rolls. In larger modern plants, polyester and nylon are produced in continuous polymerization units in which the melt is directly transported from the final polymerizer to the melt-spinning unit. In the case of polypropylene, since polymerization leads to a solid product, it is separate from the spinning process.