Effects of Guiding Routes and Grain Direction of White-clay-coated Paperboard on Tearing Characteristics of Zipper Pull Tab

Abstract

A zipper pull tab is used to open a flap by tearing the zipper dash lines, which are produced by using a nicked blade. There are various empirical design patterns of the zipper pull tab depending on the geometrical features. In order to arrange and classify these various patterns of the zipper pull tab, the tearing characteristics of the zipper- connecting portion must be clarified, while changing some representative parameters, such as the pitch of nicks and the profile of the entry guide parts. In this work, in order to reveal the effect of the guiding route on the tearing characteristics, several fundamental patterns were chosen and the tearing tensile force response and breaking modes of the connecting portion were experimentally investigated while varying the geometric parameters and the grain direction of paperboard. Appropriate guiding routes embedded in the band zone contributed to the cutoff of connecting portions when the perforation of the zipper band was across the grain direction of the paperboard. The success rate of tearing connecting portions was statistically analyzed with respect to the pattern of the guiding route. It was found that the inhibition of delamination after passing through the torn zone was necessary to successfully cut off the connecting portions.