07-01-1970 дата публикации
Номер: GB1176813A
1,176,813. Moulding foamed articles with integral hinges. ROLINX Ltd. 16 July, 1968 [26 July, 1967; 30 April, 1968], Nos. 34400/67 and 20470/68. Heading B5A. [Also in Division B8] A hinged article comprising two foamed thermoplastic polymeric articles, each with an integral solid skin joined by an integral hinge of non-foamed material is made by injecting a composition containing a thermoplastic polymeric material and (at least in part) a blowing agent into a mould comprising a pair of opposed surfaces and a hinge defining component. The polymer temperature is above the activation temperature of the blowing agent, but the mould surface temperature is below, causing a non-foamed skin to form on the foamed members. Foaming is prevented at the hinge by the small spacing between the hinge defining component and the opposite wall. In the mould shown, the hinge is formed by heated member 5 which is pushed downwards into the position shown, destroying the foam structure. In a second embodiment, a non-foaming mixture is introduced into the mould to form the skin and hinge, the top of the mould 1 excluding the hinge defining member 5 is raised and a foaming polymer is injected into the preformed skin. In another embodiment, a preformed hinge of non-foamed polymer or textile fabric is clamped between the hinge defining member 5 and a projection from the base 2 with its ends extending into the moulding cavities and the foamed members are formed in the cavities and become integrally bonded to the hinge. The polymer may incorporate fillers or pigments such as glass or asbestos fibres or glass or mica plats and the polymer may be polypropylene, a polyamide, a polycarbonate, ABS, a polyacetal, a polyphenylene oxide, a polysulphone, PVC, polyethylene or polymethylmethacrylate. The process may be used to produce blanks for boxes or similar containers, the sides, base and top being foamed sheets with a non-foamed outer layer joined by moulded hinges with optional unfoamed tags ( ...
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