| 摘要 |
817,350. Laminates; seaming non-metallic sheet materials. ST. REGIS PAPER CO. April 26, 1957, No. 13323/57. Classes 42 (1) and 140. [Also in Group XVII] A laminate comprises a flexible sheet of foamed polystyrene, having closed pores and a continuous skin, bonded to a sheet of paper, cloth, metal foil, or plastics material. The laminate may be used for making disposable containers for hot drinks, in which the polystyrene layer forms a heat-insulating and waterproofing inner or outer layer, or may be used for making boxes or other containers, or as a lining for jewel cases or packing between glass or polished metal sheets, in view of the softness and high friction of the polystyrene layer, or, since the layer can be readily printed, for making waterproof labels. As shown, polystyrene containing foaming ingredients is extruded from a heated extruding press 21 through an annular orifice 24 to form a tube 26 which foams on emergence and is inflated with compressed air supplied through an orifice 25. The inflated tube is flattened by rollers 28, 29, compressed between rollers 30, 31, bonded between compression rollers 36, 37 to paper webs 34, 35 coated with poly vinyl acetate or other adhesive at 40, 41, and slit by disc knives 42 on each edge into upper and lower laminated sheets which are cut into pieces of the required size by a guillotine 45. In modifications: (1) the rollers 36, 37 are dispensed with, lamination being effected by the rollers 30, 31; (2) the polystyrene tube is slit into separate webs before lamination, these webs passing around rollers such as 36, 37, which may be embossing rollers, and being laminated to the paper webs either on the inner sides during passage between superposed rollers, or, after passing around such rollers, on their outer sides between further pairs of rollers. The embossing of the polystyrene layer may be superficial only, as in Fig. 5, or such that it adheres to the paper web only at spaced points, as in Fig. 7. In making a drinking cup, Fig. 10, from a strip of the laminate obliquely cut at each end and rolled helically, polystyrene layer inwards, the overlapping edges being secured by adhesive, and one of the edges may be stripped of polystyrene, e.g. abrasively or by an adhesive-coated roller, to produce a paper-to-paper joint, or the foam on this edge may be consolidated by a heated roller or by the application of a solvent and pressure; in either ease any gap between the polystyrene layers, which would expose the paper to hot liquid in the cup, may be filled with adhesive. |
