Strech Wrap Film Cling Test Fixture
ASTM D5458 describes a test method for testing the peel cling of clear, polyethylene stretch wrap film. Stretch wrap is commonly used in the logistics and packaging industry to secure multiple boxes onto a pallet. Multiple layers of film are commonly used which enhances the overall durability of the entire package. This durability strength is a function of both the tensile strength of the stretch wrap as well as the peel cling resistance.
Peel Cling is also an important metric for thin film manufacturers who may be combining several films together to create a web.
Testing peel cling requires preparing two different types of samples. The first sample is larger and acts as a substrate or backing. The second piece is a smaller strip which is peeled off of the larger sample.
The ASTM D5458 fixture is specially designed for this test. It is about 500mm long by 150mm wide. There is a metal roller camp that is situated towards the back of the grip which is used to secure the larger square-like sample specimen.
The smaller specimen is attached to a clip and is pulled by a string after it has clung to the larger specimen backing. This string is wrapped around a pulley which can be seen in the bottom left of the picture. The pulley redirects the up and down motion of the tensile testing machine.
The main calculation for this test involves taking an average of the entire data set. The user may choose to eliminate specific data points towards the beginning or end of the test. Spikes and valleys should be noted and recorded as well, depending on the exact goals of the test