GB928994A - Manufacture of plastic sheet materials - Google Patents

Abstract

928,994. Moulding plastics terrazzo sheet flooring. AMERICAN BILTRITE RUBBER CO. Inc. Oct. 30, 1961, No. 38683/61. Class 87(2). Coarse plastics granules are moulded without visual loss of individual identity, into continuous sheet material for plastics flooring of the terrazzo type. Granules in different colours are delivered from a granulator into a lagged storage bin 10, heated by steam or electrically heated coils 74, thence along a transversely extending distribution head 14 by screw conveyer 16 and from which a substantially uniform distribution is achieved along and into a feed hopper 24 by ports 18 having adjustable closures 20. The granules are discharged across conveyer 26 in a controlled uniform layer through individual gates 32 having plates 34 vertically adjustable from bolts 40 and carrying blades 46 angularly adjustable from bolts 48 and are heated, by passing under radiant elements 76, to a softened condition below their melting point before feeding to the press 60, where consolidation to a compact sheet occurs. The press 60 consists of a heated drum 62 partly surrounded by an endless steel tension band 64, adjustable from tension roller 70 horizontally movable by hydraulic means, and through which heat is supplied to the plastics sheet by curved heater 72. Control of the layer of granules is additionally provided by variable speed drives to screw conveyer 16 and belt conveyer 26. In an alternative embodiment, Fig. 3 (not shown), the hopper 24 is recessed for greater convenience of adjustment of gates 32 and discharges on to an intermediate conveyer belt driven by a variable speed unit prior to delivery on to the belt to pass under heaters 76 for delivery to press 60. The plastic granules may comprise plasticised and pigmented vinyl chloride.