GB728232A - Improvements in or relating to processes of and apparatus for melting melt-spinnablesubstances - Google Patents

Abstract

<PICT:0728232/IV (a)/1> Solid particles of a melt-spinnable substance, particularly a high polymer such as a polyamide, are continuously fed to a melting chamber; a portion of these particles is melted by contact with solid heating surfaces located in the melting chamber; that portion which has not been so melted is retained within the melting chamber and melted by heat exchange with a stream of the same substance in the molten state, this stream comprising the liquid obtained from the particles which are melted by contact with the solid heating surfaces; and all of the molten substance is allowed to collect in a reservoir located in the lowermost portion of the melting chamber. The stream of molten substance used for melting that portion of the solid particles which is not melted by the solid heating surfaces may be augmented by molten substance drawn from the reservoir. As shown in Fig. 1, granules, chips or like particles of solid polymer 10 are fed from a supply-vessel 11 to a melting apparatus 12. This apparatus comprises a funnel 14 which is heated by electric resistances 15 or by other means so that particles of solid polymer coming into contact with the walls of the funnel melt and the resulting liquid penetrates into the lower part of the apparatus. The central mass of the solid polymer descends by gravity concurrently with the liquid, leaves funnel 14 and falls into an unheated basket 16 where it is washed by the liquid polymer and heated thereby so that it melts. The undissolved mass of particles in the basket acts as a filter bed for the liquid. Molten polymer drips from the basket and is collected in sump 17. Inert gas may be circulated through the apparatus 12 by way of inlets 19 and outlets 20. The temperature of the whole apparatus may be maintained at a desired value by means of fluid circulation in one or more jackets 21. From sump 17, the liquid polymer passes to a pump 22 and spinneret 23. According to the shape of the orifices, filaments, ribbons, rods, sheets or other articles may be obtained. Preferably the conditions of operation are adjusted so that part of the basket 16 and the solid polymer therein are immersed in the liquid collected in the sump. The rate of melting of the solid so immersed is less than if it were above the liquid level. The melting thus becomes self-adjusting according to the consumption, since the liquid level rises if the rate of consumption decreases. The heating devices may be thermostatically controlled. If desired, the melting apparatus may be provided with a pump and conduits for removing some of the liquid from the sump and returning it to the basket 16 so that it descends through the mass of solid polymer therein and assists in the melting of the solid polymer. Heating devices may be provided along the pipe line through which passes the recirculating liquid from the sump. Specification 728,233 is referred to.