| 摘要 |
1,158,361. Seaming non-metallic sheet material. TETRA PAK A.B. 13 Feb., 1967 [23 March, 1966], No. 6819/67. Heading B5K. [Also in Division B8] A carton having a plastics coating, of the type closed by folding together its end closure panels and heat-sealing their abutting edge portions, has a thermoplastic sealing layer, of lower melting point than the coating, applied to portions of the closure areas, thus preventing adhesion between portions uncoated with the sealing layer during heat sealing. The invention is described in relation to a peak top carton. A sealing layer, e.g. of low density polythene, is applied to the stippled areas of the blank of Fig. 3, which is made of e.g. stiff paper coated with polypropylene. After filling and heat-sealing, the concertina fold constituted by panels 4, 6 may be pulled out to form a pourer, since no sealing layer was applied to flap 10. |
