In many applications it is necessary to fix a foil or a film in a tight and detachable manner to a base of plastic material which mainly consists of oriented material. In the following, without any restrictive significance, the designation film is used for the foil or film which is to be fixed to the base. The structure of the film varies from occasion to occasion and is constituted in certain applications of a single-layer film, e.g. of plastic material or of metal, and in other applications of a laminated film. In laminated film the layers consist, for example, simply of plastic material when the composition of the material as a rule varies from layer to layer whilst in other applications one or more of the layers consistopening is closed by means of a film, is therefore not acceptable, since on the one hand the film is defored to an extent which makes the container unacceptable to the consumer, whilst on the other hand the film sticks to the edge of the opening so strongly that it cannot be torn off.