The Effect of Stretch Wrap Prestretch on Unitized Load Containment

Abstract

There are three main factors affecting the stability of a palletized load that is unitized by a stretch wrapping mechanism – the type of unitized load, wrapping configuration and shipping method. The wrapping configuration is typically determined on the basis of the type of unitized load and shipping method. For this study, the aforementioned components were referred to as the package, the product and the distribution environment. This study was designed to observe and understand the interactions between each of the components of the stretch wrap system. Prior to stretch wrapping a pallet of product, the film is elongated or prestretched. The elastic nature of the stretch wrap forces the film to conform to the palletized load. It is hypothesized that the containment force that the stretch wrap applies to the palletized load contributes to improved load containment. Hence, the objective of this study was to determine the existence of a correlation between percentage prestretch to change in containment force and load containment. For the study, a range of prestretched unitized loads were subjected to International Safe Transit Association 3E distribution testing. Simultaneously, the containment force was monitored during the period of distribution testing. Subsequent to distribution testing, the load dispersion was quantified. The data obtained from this test suggested that there is no correlation between percentage prestretch and change in containment force or load containment. Copyright © 2014 John Wiley & Sons, Ltd.

Load Securement and Packaging Methods to Reduce Risk of Damage and Personal Injury for Cargo Freight in Truck, Container and Intermodal Shipments

“…Proper use of plastic film stretch wrap is an effective load stabilization method 28,29 . As mentioned earlier it is important for a shipper to understand the weight sizes and types of mixed loads to use appropriate amount of wrap with necessary tension and additives if long term and outside exposure is expected.…”

Measuring the mechanical and climatic conditions encountered by palletized products in handling and transport

“…In [66], the correlation between pre-stretch and stretch film, force containment, and load containment was analysed. As unexpected result, it was noted that, after an initial positive influence, the level of pre-stretch in the film does not provide a significant impact on stability and protection of packaging.…”

Evaluation of Stability of Unit Loads for Tilt and Shock Events During Distribution

“…There are multiple ways of unitizing a load including stretch wrap, stretch hood, stretch net, and strapping or banding [6]. A few recent studies have investigated the specifications for the stretch wrapping operation as related to load stability [7][8][9][10][11][12]. As related to stretch wrapping and its effect on a unit load's stability, it is critical to undertand how packaging, pallets and handling equipment interact.…”

“…Load containment allows a load to be securely held in place so it can arrive undamaged at its desired destination. Proper stretch film application increases load containment [7]. Stretch film is properly applied when the film is stretched, applied under tension, and elastic recovery conforms the film to the load [14].…”