GB586425A - Method and apparatus for producing continuous lengths of shaped structures of synthetic organic thermoplastic material - Google Patents

Abstract

Filaments or like structures of organic thermoplastic material in continuous lengths are produced by feeding the freely exposed end of a supply of the solid thermoplastic material into a short zone of radiant energy in which the thermoplastic is locally melted and, at the same time, exerting a pulling action at one or <PICT:0586425/IV/1> <PICT:0586425/IV/2> more points of the exposed end. As shown in Fig. 1, solid thermoplastic material 10 is fed by means of driving rollers 12 into or near the focus F2 of an ellipsoidal reflector 17 which has, at its other focal point F1, an incandescent wire or lamp 16 which is heated electrically. The filament 18 cast upon the winding drum 19 exerts the pulling action upon the exposed end of the material 29. In a modification of this apparatus, a number of lamps are arranged in a plane at right angles to the exposed end 29 so that the radiant energy is focused at points of the material in that plane. In another form of the apparatus the energy is focused at points of the material in such a way that the material is heated in stages. In yet another form of the apparatus, the thermoplastic is preheated by means of a heating coil surrounding but apart from the thermoplastic material. As shown in Fig. 5, the preshaped solid 40 is tubular. A number of lamps are arranged in the plane AA at right angles to the tube so that the radiant energy is focused at points, such as 51 and 52, from each of which a filament 18 may be drawn. A number of filaments may be similarly drawn from a rod supply of material. The tubular material may be used as a means of introducing an inert gas atmosphere to the heated zone. A tubular structure may be drawn from the closed end of a tubular supply and prevented from collapsing while plastic by the pressure of the inert gas. The thermoplastic material may be polystyrene, a vinyl resin, polymethyl methacrylate, a polyamide, a cellulose derivative or a rubber-like plastic such as polyisobutene. The radiant energy may be heat, light concentrated by a lens system or the electrical energy of a high-frequency electric field.