| 摘要 |
There is disclosed a method of producing gas-tight and liquid-tight containers, especially collapsible tubes wherein a strip of plastic coated carrier foil is bent or wound into the shape of a substantially cylindrical tube, the longitudinal edges of the strip being arranged in overlapping relationship. These longitudinal edges are then heat-sealed and the tube is coated with a sheath of plastic for covering the overlapping seams and providing a smooth continuous outer surface capable of receiving an imprint. Further, according to the invention the amount of plastic material and application thereof to the surface of the tube is controlled such that the outside surface of such tube when covered with the plastic sheathing possesses a shape and dimension substantially corresponding to the internal receiving wall of a mold cavity for heading the tube. The tube, typically after having been cut into finite tube sections, is then inserted at one end into a mold cavity, the outside surface of such tube section snugly fitting in good sealing relationship against the internal receiving wall of the mold cavity. The inner wall of the tube section, at least at the end region thereof received in the mold cavity is freely exposed, so that when moldable material is introduced into the mold cavity it contacts such exposed inner wall, thereby producing a substantially radially directed force applied outwardly against the inner exposed wall of the tube, urging the outer wall thereof into extreme sealing contact with the internal receiving wall of the mold cavity so that an extremely effective seal appears at the location where the tube section has been inserted into the molding cavity.
|
