Filament melt spinning

摘要

In the prodn. of filaments from molten polymers, the cold gas stream flow below the outlets for the molten filaments, at a small gap from the openings, has a speed greater than the molten filament speed. The gas flow gives a constant acceleration to the filaments so that they are drawn and cooled. Also claimed is a melt spinning assembly with an outlet slit below the centre axis of the spinarette opening rows, with a smaller cross section than the side flow cross sections. This gives a constant acceleration in the flow from the arrival of the gas at the filaments to the narrowest section of the slit. Pref. the technique is for melt spinning of molten polymers into filaments such as polyamide, polyester, polystyrene, polyurethane, polypropylene, and the like. The gas, after compression, is fed directly to the spinning station, without heat applied to it or taken from it, with pref. air for the gas flows. The gas is delivered to the filaments, at their setting point, at sonic or ultrasonic speeds. The slit has a converging shape, as a Laval jet structure. The spinarette has a lower thermal insulation, or has additional lower heating, to prevent heating of the gas streams.