Evaluation of Containment Force Variability between Different Grades of Stretch Film

Abstract

Containment force is a measurement often used to qualify stretch films when they are applied to a unit load of packaged product. This measurement records the amount of resistance force a stretch film delivers when being displaced a specified distance. It has been the industry perception there are quality differences between commodity and high-performance grade stretch films. These perceived quality differences are believed to affect the variability between different grades when being examined in a laboratory. In order to evaluate this theory, two different grades of stretch film from two different manufacturers were applied to an instrumented test pallet and the containment force was measured. Results from this study showed there were no statistical differences between the variability of containment forces of different grades of stretch film between the same manufacturers. While the study was limited to only two manufacturers, the results indicated there is less variability between commodity and high-performance grade stretch films than was originally theorized. Additionally, it was observed that a predetermined containment force measurement of 25 lbs. could be obtained through a variety of different stretch wrapping parameters and equipment settings. Many of the developed patterns and settings used would have resulted in load shifting and/or load failures during actual transport. As a result of these observations, it was recommended to use containment force measurements as part of a quality assurance program and not a predictor of success during transportation.