| 摘要 |
A method for producing a tube (3), with a wall containing over 60 vol % of a plastic material, from an essentially cylindrical tubular blank (4) with inner and outer surfaces made of one or more polymeric plastic materials, said tube (3) having a body (40) and a necked head (7). The method comprises necking an end portion (5) of the blank (4) by bringing together inner (1) and outer (2) tool assemblies to produce crumple folds (13) on said portion (5). The method is charactized in that a) before the necking step said blank (4) is heated so that said portion (5) is, at the time of necking, at a temperature no lower than the melting point of each of said polymeric plastic materials forming the inner and outer surfaces of the wall of said blank (4), said materials being in a viscous molten state at the time of necking; and b) said crumple folds (13) are produced during the necking step simply by bringing together said tool assemblies (1 and 2) to squeeze the folds (13) therebetween and seal them together to give said necked head (7) with at least one resulting shaped shoulder (8). The resulting tubes, which keep the flavour of packaged materials, and an improved dispensing arrangement, the tube shoulders being squeezable sideways, are also provided. |
