Patent GB-1333247-A (GB)
Title: Method and apparatus for plasticizing thermoplastic synthetic resin
IPC: B29C48/06
Filed: 1970-10-16
Abstract: 1333247 Heat plasticizing apparatus MITSUBISHI PETROCHEMICAL CO Ltd 16 Oct 1970 [17 Oct 1969 18 Nov1969 23 Feb 1970 24 Feb 1970] 49204/70 Heading B5A [Also in Division B1] A plasticizing apparatus for thermoplastic synthetic resin comprises a rotatable frustoconical container 14 with means such as a screw 4 for supplying material to the smaller diameter end, a heater 54, a core 44 rotatable with the container and an outlet at the larger diameter end. As shown in Fig. 1, there is a stationary conical discharge funnel 38 with a discharge passage 41 which is rectangular (see Fig. 3, not shown). The apparatus has a doublecone core the apical angle of which is greater than that of the container and which rotates therewith. The material is heated also by friction and the apparatus is rotated at such speed that the centrifugal acceleration of the material is at least 5g. In modifications the container may have three sections of different angle (see Fig. 4, not shown), the core may have protuberances (60, Fig. 7, not shown). It may have only a single core, be hollow, or of parabolic shape (see Figs. 12-14, not shown). There may be inward projections (92, Figs. 15-20, not shown) in the inner wall of the container. The container wall may have a step to accommodate a cylindrical screen (121, Fig. 23, not shown). There may be a conical rotatable core member within the discharge funnel 38; it may have a spigot extension (116, Fig. 22B, not shown) into the discharge passage, or spiral grooves (114, Fig. 27, not shown) on its face. Extrusion.-Fig. 8 shows an arrangement for extruding a tube in which material is fed into a box 61 which it leaves by a port 62. The conical core 64 is axially displaceable to adjust the annular gap 66 which discharges to an annular die 71, which may be replaced by one having apertures of circular, square or arcuate shape for extruding strands, (see Figs. 9-11, not shown). In another arrangement (see Fig. 24, not shown), the tube is formed by passage of the material between a stationary mandrel (131) and an external ring which extend within the core and outside the container respectively to form a rotary seal. In a further arrangement, (Figs. 33-35, not shown), the product is discharged through peripheral apertures (221) in a fixed discharge member (218) at the wider end of the container, having a cutter (225) for forming granules which are blown by a compressed air jet 227 into e.g. a cooling bath.  An apparatus, Fig. 36, vertically arranged and especially suitable for reclaiming wastes has core members or baffles 257, 258 rotating with the container 259, and is discharged by a gear pump 267 to an extrusion device 269 which forms a film which passes to a draw-cooling device 270. In a vertically arranged apparatus for plasticizing while mixing in stabilizers, fillers, reinforcing materials and pigments, Fig. 38, materials fall through aperture 292 in the upper of the two dished discs 290,294 and are mixed and scattered by blades 291, 295. There is a rotatable dome-shaped member 298 defining an annular discharge outlet 301 and an annular opening 307 for extruding a tube. Centrifugal casting.-The container may discharge into a cylindrical rotatable mould 147, Fig. 29, for centrifugally casting tubular bodies from which other shapes can be cut, (see Figs. 30-32, not shown). The mould is transferable on rails 179 from the position shown in broken lines in which it receives material from the plasticizer. to one below the water cooling device 204. In operation it is rotated at a speed such that the centrifugal acceleration of the resin is greater than 2g during filling and preferably greater than 5g during cooling.