GB1253980A - Process and devices for the continuous production of continuous pieces from reactive mixtures - Google Patents

Abstract

1,253,980. Moulding polyurethane strips. PAPIERFABRIK G.m.b.H. 21 Nov., 1968 [28 Nov., 1967; 19 Dec., 1967], No. 55317/68. Heading B5A. Continuous circular plastics sections, which may be solid or tubular, are continuously moulded from a liquid resin reaction mixture of polyisocyanates or polyhydroxyl compounds based on polyester or polyethers, which is continuously introduced into the upper part of a continuous moving cavity defined by at least one moving endless element. Continuous sections such as rods, sealing strips, or elastic cords may be produced and continuous reinforcement or cores may be fed into the cavity when the reaction mixture is advantageously simultaneously introduced therein. Metal tubes or rods may be provided with shock or abrasion resistant coverings, and electrical conductors provided with insulating coverings and a plurality whereof may then be twisted together and similarly covered. In one form of apparatus, Fig. 2, an endless flexible element 14, comprising a longitudinally slit tube, is closed to define a cylindrical cavity on passage through a guide 18 provided with downwardly inclined openings 40 from a guide chamber 36 through which lubricant, e.g. oil, silicone, or air, is fed under pressure from a pump 42 to facilitate passage of the element 14. The guide 18 is also provided with a chamber 44 through which heating fluid, e.g. water, oil, steam or gas, is upwardly circulated. The liquid resin reaction mixture is introduced, preferably on to a cable 62 if incorporated, by a nozzle 22, supplied from a resin component mixer 24 which is adjustably mounted at a hinge 34 on a horizontally adjustable slide 32. The element 14 may be profiled in the cavity defining surface thereof. Opening of the element 14 beneath the guide 18 is assisted by a wedgeshaped element (52), Fig. 1 (not shown). Alternatively, Fig. 13 (not shown), a plurality of parallel cavities (70) may be defined between a pair of co-operating endless flexible belts (66, 68) passing through a similar lubricated and heated guide, the belts aligning at co-operating grooves and recesses. Alternatively, Figs. 11 and 12 (not shown), a plurality of continuous cavities may be defined between two endless chains of pivotably connected mould parts, adjacent parts being provided with co-operable pegs and recesses and co-operable grooves and recesses also being provided on respective chains thereof to ensure alignment when the mould parts are closed on passage between roller tracks. In a further alternative embodiment, Fig. 16, a single endless chain is employed comprising a series of co-operable mould parts which are hingedly connected at 158 and urged to a closed position, against springs 170, by devices at the entry to a guide defined by roller tracks 192 and which devices are reciprocated by doubleacting hydraulic or pneumatic cylinders which are operated by electromagnetic valves actuated by stationary spaced apart switches which are operated by cams on the mould chain. The mould parts may be heated by infra-red, heated air, or by induction. The endless cavity defining element or elements may comprise an antiadhesive material based on silicone, or may be coated with a silicone material.