GB1156205A - Improved Moulding Materials - Google Patents

Abstract

1,156,205. Coating with preformed sheets. REDLAND BRICKS Ltd. 30 June, 1966 [12 July, 1965; 5 April, 1966], Nos. 29470/65 and 15160/66. Heading B6G. [Also in Divisions B5, C3 and D1] A moulding material comprises a homogeneous mixture containing more than 50% wt. finely divided inorganic material, fibrous material and less than 30% wt. of a synthetic resin, in the form of a compacted sheet in which all of the fibres lie in planes parallel to the major surfaces of the sheet. The inorganic material can be sand, granite dust, limestone dust or quartz. Flame-retarding or fire-extinguishing fillers, and pigments can be included in the mixture. The fibrous material can be fibres 0À1-1À5 inch long formed of glass, asbestos, sisal and be used in the amount of 2-15% of the total mixture. The resin can be a polyester, epoxy or acrylic resin and may also contain benzoyl peroxide, aluminium stearate, zinc stearate or t-butyl perbenzoate. The cured moulding can be rigid or have a slight flexibility. The moulding material is made by mixing the constituents and subjecting the mixture to compaction so as to align the fibres. The mixture can be compacted by nip rollers, oscillating pressure plates, extrusion, steel balls or grooved wheels. Before compacting the mixture may be vigorously combed to produce a fluffy mass, by feeding the mixture from a hopper (2) through rollers (3, 4) on to a spiked rotor (5) which tears at the mixture and projects it toward a pair of compacting rollers (7, 8) see the Fig. (not shown). The moulding material can be moulded at temperatures of 60-150‹ C. and pressures up to 250 p.s.i. The moulding material can be decorated with patterns. The moulding can be hollow and so-formed by wrapping the compacted sheet around a removable core and cured. Hollow sections can be filled with stone rubble, liquid cement or fire-resistant materials. The moulding can contain wire mesh, metal grids or conduits. The moulded sheet can be wrapped around a core, e.g. a foamed polyurethane slab, polystyrene foam, woodwool cement slab or compressed straw slab, the sheet shrinking on curing. Pipes may be formed by wrapping the sheet around a removable core and curing under heat and pressure. Two or more of the compacted sheets can be combined before curing, e.g. by cold or hot (90‹ C.) pressing for 5 mins. The layers can be of different composition or colour so as to form, for example, window frames or tubes having different finishes on the inside and outside of the frame or tube. A metal grid reinforcing layer, or a layer of low cost material, can be incorporated between two sheets. Texturing agents, e.g. pigments and pebbles, can be incorporated in the surfaces before curing. Sheets can be joined by edge butting, rolling then curing, e.g. to form a zebra crossing.