GB1469540A - Hardened moulded bodies having cavities extending therethrough - Google Patents

Abstract

1469540 Moulding panels having bores extending therethrough SEMPERIT AG 2 July 1974 [2 July 1973] 29223/74 Heading B5A Apparatus for producing panels, having bores extending therethrough, from a composition containing particulate material bonded by a heat-hardenable resin, comprises a mould cavity defined by a closure member 4, support structure, and sides 6, and at least two inflatable core devices 7 adapted to be inserted into the mould cavity, the cores being inflatable by a heating fluid so that the material being moulded may be more effectively heated from within the bores formed by the inflated cores. As shown in Fig. 3, each core device 7 comprises a membrane 10 supported by a perforated tube 9, heating fluid being fed, as shown by the arrow A, into the tube 9 and through perforations 13 to inflate the membrane 10. The heating fluid is vented from the membrane through an annular passage 18 defined by a flange 12 and the tube 9. A metal tip 14 which is either screwed into, or integral with, the tube 9 facilitates insertion of the device 7 into the moulding material. In use, the mould is filled with the moulding composition, and the devices 7 inserted and inflated, heating being effected either simultaneously with the bore forming or subsequently thereto. If desired, preformed reinforcing strips of polyester may be positioned at the edge regions of the mould before filling with the remainder of the moulding material. Alternatively, these edge regions may be filled with a strengthened moulding material, e.g. a concrete/synthetic resin mix. Reinforcing elements, e.g. of steel, may also be positioned in the mould before filling. A suitable composition for moulding comprises (a) 5-60% of a first porous inorganic material, bulk density <0À25 g./cm.<SP>3</SP>, granule size <10 mm., (b) 15-80% of a second porous inorganic material, bulk density >0À25 g./cm<SP>3</SP>, and/or 0À5-10% of a synthetic resin foam, volumetric density 8-100 g./l., (c) up to 40% rubber granular and (d) synthetic resin binder. The first inorganic material may be perlite, the second metallurgical slag, expanded clay, or foamed cement droplets. The synthetic resin foam may be polyurethane or polystyrene. The binding agent is preferably used in 8-50% by weight, and may be urea formaldehyde resin. Reinforcing fibres may also be incorporated. A layered panel may be produced by feeding the material into the mould in discrete layers of a different composition. A panel comprising expanded clay may have a central layer with clay of granule size 15-20 mm. and outer layers of granule size <7 mm. Alternatively, a weather-resistant resin such as melamine, polyester, polyurethane, epoxy or acrylic may be used for the outer layers.