A structure of zipper band is used for opening a cover or splitting a panel by tearing the zipper dashed lines, which are processed by using a repeatedly nicked (perforation formed) wedge blade. To arrange the geometrical design parameters of the zipper band of a package box, the tearing characteristics of the zipper-connecting portions must be clarified. Herein, to investigate the tearing strength and the success rate of connecting portions (uncut zones) of corrugated board in the fabrication machine direction, the length of connecting portions, the width of zipper band, the phase shift angle between two dashed lines, and the pulling velocity of the cramped end of the zipper band were changed in the tearing test of the zipper band. The experimental results show that the outside (lower side) liner was de-laminated and tore protrusion occurred at the connecting portions in the band area. For the upper critical length of connecting portions, at which the success rate became zero, the upper bound tearing strength was obtained and is related to the Elmendorf-like tearing value by the uniaxial tensile test.

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