GB954377A - Improvements in or relating to the production of laminated structures - Google Patents

Abstract

954,377. Laminates and laminating. LONZA Ltd. Dec. 14,1960 [Dec. 14, 1959], No. 43031/60. Heading B5N. Rigid, semi-rigid or flexible sheets of foamed plastic material, of the closed-cell type, particularly foamed unplasticized polyvinyl chloride, are continuously bonded on one or both faces to sheets of aluminium or other metal, wood veneer, paper, plastics foils, e.g. hard or soft polyvinyl chloride, or open or close mesh textiles which may be embossed or printed, by coating one or both surfaces to be bonded with adhesive, moving the superimposed layers through a heating and then a cooling zone, and applying an exterior compressive force throughout the whole or parts of the two zones. One or more of the sheets may be preheated. As shown, a sheet 3 of foamed plastics material having superimposed sheets 4, 5 of other material with interposed adhesive layers 6, 7 is enclosed between plates 8, 9, which may be somewhat wider than the sheets and may have side plates such as 50 to confine them. The plates 8, 9 may be of steel, bronze, copper or other metal, of wire netting, or of textile or plastics material with or without metal reinforcement, and may have perforations or embossments to engage the sheets 3, 4, 5 frictionally and impress a design on them. The plates 8, 9 are connected at their forward ends by a plate 26 by which they may be moved through the apparatus by haulage means 27, 28, 29. The sheets 3, 4, 5 are entrained between heating chambers 11, 12 containing electric heating wires 11<SP>1</SP>, 12<SP>1</SP> and between chambers 21, 22 containing cooling means, both pairs of chambers being tapered over part or the whole of their length to apply progressively increasing pressure on the sheets. Flared guides 17, 18 may be provided at the entrance to the heating zone and these may be heated, the first part of the chambers 11, 12 then being unheated. In a modified apparatus a pair of endless belts arranged to taper towards their delivery ends is used to compress a sheet of foamed material enclosed between sheets of flexible material coated with thermoplastic adhesive and delivered from rolls along paths adjacent to infrared heaters used to activate the adhesive. Heating and cooling chambers are located on each side of the operative flights of the belts. Only one cover sheet may be applied, and in that case heating and cooling apparatus is used on one side only. In examples hard polyvinyl chloride sheets are laminated to closed-cell foamed hard polyvinyl chloride with a 75: 25 copolymer of vinyl chloride and acetate as adhesive, and aluminium foil is laminated to one side only of a foamed sheet with the same adhesive containing also maleic acid. The products may be made into insulating, reinforcing or moisture-resisting panels.