| 摘要 |
A multi-layer bonded foil 10 which forms the inner wrapper of a cigarette pack is provided with a tear line 14 to facilitate opening a tear flap 15. The tear line is formed by a fixed lower tool 25 having a raised rib 28 flanked by grooves 29, 30 and a reciprocable upper tool 20 having a pointed edge 21 and movable between guide supports 22, 23. The upper tool is heated and forced into the foil to stretch-weaken its upper polyester layer 11 and central aluminum foil layer 12, and to simultaneously heat soften and deform its lower polyethylene layer 13. |
