| 摘要 |
1,206,667. Production of packages; portable containers. SIDAPLEX S.A. 16 April, 1969 [15 May, 1968], No. 22966/68. Headings B8C and B8D. In a process for the production of a package, e.g. a container 4 for milk and which can be used as a disposable cup, a sheet 6 of biaxially orientated thermoplastic resin such as polystyrene, is heat sealed to the rim of the open container so as to form a lid and a knife 9, extending along an inner edge of the seal, is simultaneously pressed into the heat-softened sheet to a depth less than the thickness of the sheet so that a line of weakness 13, resulting from the pressure of the knife 9 on the inner edge of the seal, facilitates opening of the package when required. A succession of open containers (4), Fig. 1 (not shown), are passed from right to left, between heatable and unheated upper and lower jaws 1, 2 respectively of a heat sealing press, the jaws 1, 2, conforming generally to the rim 3 of a container, being arranged for relative vertical movement so that, when they are brought together, a sheet of biaxially orientated resin 6 is heat sealed to the container rim forming a lid and the knife 9 penetrates, e.g. to one-third of the thickness of the sheet 6, to produce the line of weakness 13. An outer knife 8 on the upper jaw 1 cuts through the sheet 6 so that the unused portion 11 of the sheet 6 can be torn away as it bends upwards over the roller 12. The sheet 6, made, e.g., of polyacrylates, polymethacrylates, polycarbonates; P.V.C.; polyethylene terephthalate; isotactic polypropylene and styrene copolymers, can have a thickness between 0À01 and 0À5 mm., e.g. 0À05 mm., the seal preferably being made as narrow as possible consistent with the production of an effective seal. The depth of the weakness is preferably between one quarter and two-thirds the sheet thickness, also a gap may be provided in the knife so that, after the weakness has been broken the lid remains hinged to the container rim. |
