| 摘要 |
1327280 Heat sealing packages TETRA PAK INTERNATIONAL AB 3 Dec 1970 [10 Dec 1969] 57534/70 Heading B8C [Also in Division B5] Packaging material 6 comprising a layer 1 of metal foil together with a layer 2 of a thermoplastic material in which the layer of thermoplastic material constitutes a sealing layer of a package, is arranged so that the layers of thermoplastic material are held against each other and pressed together and are heat sealed by high frequency electric heating which heats the foil layers to bring about fusion of the thermoplastic sealing layers. As shown in which the packaging material is in the form of a tubular web consisting of a layer of paper, an inner sealing layer of e.g. polythene or polypropylene, a metal foil layer of e.g. aluminium and bonding layer 9, the tube is filled and subsequently divided by transverse sealing zones 7. The zones 7 are formed by sealing jaws 4, 5, one of which is provided with a coil 3 substantially flush with the pressure surfaces thereof and connectable to a high frequency generator, the frequency generated being between 0À5 and 2 MHz. The coil 3 may have a ferrite core. |
