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AssigneeStora Enso Oyi
InventorsPaivi Maeaettae, Risto Vesanto, Panu Tanninen, Petri Laakso, Jari Hovikorpi
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The invention relates to a method for manufacturing a board tray (7), to a tray blank feasible for the method, and to a tray obtained by the method. The method comprises moulding a blank of plastic-coated board into the tray (7) comprising a bottom (3), side walls (4), as well as a rim flange (5), the blank being compressed in a direction transverse to the tray's side walls and rim flange. According to the invention, the blank is made thinner on its side opposite to the plastic coating such that, during the moulding process, the plastic coating double-folds at the compressed parts and stabilizes compressions (8) by becoming sealed to itself. Making the blank thinner is most conveniently effected by carving the board layer with a laser beam for having the fiber material predominantly or completely removed from where the cuts are located. As a result of the moulding process, the tray's rim flange (5) develops a smooth plastic surface which enables closing the tray hermetically with a heat-sealed cover.
A method for manufacturing a board tray (7), which method comprises moulding a blank (1) of plastic-coated board (9, 10) into a tray comprising a bottom (3), side walls (4), as well as a rim flange (5), whereby, in the process of moulding, the blank compresses in a direction transverse to the tray's side wall and rim flange, and plastic coating (9) of the board (10) is melted in the compressions (8) for stabilizing the tray so as to retain its shape, characterized in that in the parts to be compressed the blank (1) is made thinner on its side opposite to the plastic coating (9), such that the plastic coating double-folds in the compressions (8) and seals to itself.
A blank (1) of plastic-coated board (9, 10), which is applicable to manufacturing a tray (7) according to any of the preceding claims and which comprises sections for forming a bottom (3), side walls (4), and a rim flange (5) for the tray, characterized in that in portions corresponding to compressions (8), which will be created in the tray (7) and which are transverse relative to the side wall (4) and the rim flange (5) of the tray, the blank (1) has been made thinner on its side opposite to the plastic coating (9) such that, in the process of moulding the blank into a tray, the plastic coating double-folds in the compressed parts and is capable of sealing to itself.
Dependencies are inferred from the claim text.