Effect of Stopping Time on Time-dependent Release Behavior of Creased White-coated Paperboard and Analysis of Nonlinear Relaxation Characteristic

Abstract

Mechanical experiments have been performed to investigate the dynamic creasing characteristics of coated paperboard mainly used in the food packaging industry. The correlation between the time-dependent relaxation of bending resistance at a specified folded position and the dynamic release behavior of creased paperboard was experimentally investigated for a time period of 0.1-1000s. The transition of in-plane tensile stress relaxation and that of bending moment relaxation were detected in the time period of 10-30s in a specified paperboard, when using a constant deformation rate for creating the initially loaded state. We varied the stopping time of the folded state of a creased part, and analyzed the time-dependent released behavior (unfolded deformation) using the improved relaxation model, which is based on the power rule of relaxation time. The results obtained with this model show a good fit to the experimental results, and the proposed release time of the unfolding process is found to be almost independent of the stopping time.