| 摘要 |
PROBLEM TO BE SOLVED: To make the thickness of a ground end part uniform and smooth by jetting a superhigh pressure water from a nozzle toward from the center side to the end part of a laminated packing material to grind the end part to specified thickness and width. SOLUTION: When a superhigh pressure water is jetted from a nozzle N at high speed toward from the central part to the end part of a blank 2 of a laminated packing material which has a paper layer 5 as an intermediate layer, and on both faces of which polyethylene layers 6 are provided, the surface of the end part of the blank can be ground to an optional depth depending on the intensity of the water jet J. In this case, it is desirable that the angleαbetween the water jet J and the end face to be ground falls in the range from 30 deg. to 60 deg.. When the angleαis from 90 deg. to 60 deg., the grinding is similarly effective. When the angleαis 30 deg. or less, the borderline between the ground part and the non-ground part is not clear, and thus the grinding becomes ineffective.
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