| 摘要 |
996,920. Laminates. OLIN MATHIESON CHEMICAL CORPORATION. Aug. 28, 1963 [Sept. 4, 1962], No. 34067/63. Heading B5N. A composite unit, which may be a structural member, is made by uniting two ductile metal sheets around a peripheral area leaving an inlet for the introduction of foamable material to the interior, and introducing such material in sufficient quantity that when it reacts to form a foam it deforms the interior portions of the sheets into a desired spaced relationship. In one embodiment (Figs. 6 and 7), three sheets are pressure-welded by either hot or coldrolling around edge portions and also in strips within the peripheral area, the intermediate unwelded strips 14 between one pair of sheets being staggered in relation to those 15 between the other pair of sheets, welding of these intermediate areas being prevented by the interposition of " stop weld " material. Thus when the outer sheets are deformed outwardly by the foamed material 19 the strips of metal between welded portions of the middle sheet will be pulled across to form stiffening ribs, as shown in Fig. 7. This element is stated to be suitable for wall structures and to provide insulation and sound-damping. The foam may be injected in with sufficient pressure to partially deform the metal sheets to form a chamber, completion of the deformation being by foaming pressure; the shape of the outer walls may be modified by constraining the sheets between platens. The metal may be aluminium alloy and the foam material a polyurethane, which may be mixed before injection or, alternatively, injected as two solutions, e.g. an isocyanate prepolymer and a solution of crosslinking agents such as polyols, a catalyst, and blowing agents such as chlorofluronated hydrocarbons, water or carbon dioxide. Other foam materials which may be used are polyethylene, polystyrene, polyvinyl chloride, copolymers of acrylonitrile, phenolic resins and polyesters. A preferred foaming composition is obtained by combining specified proportions of a prepolymer (representing 4À5 equivalents of toluene diisocyanate, 80 parts of the 2-4 isomer and 20 parts of the 2-6 isomer and 1.0 equivalents of a copropoxylated tetrol mixture of methyl glycoside and pentaerythritol of OH 435) with a similar copropoxylated tetrol mixture of OH 435, a silicone copolymer, fluorocarbon 11 and stannous octate. Specifications 759,804 and 759,831 are referred to. |
