Stretch film, sometimes called pallet wrap, is engineered with high elongation and elastic recovery so it can be stretched substantially, often 150 to 300 percent of its original length on automated wrapping equipment, while being applied around a palletized load. As the stretched film attempts to relax back toward its original length, it generates a continuous inward clamping force, called containment force, that holds the boxes or items on the pallet tightly together. Most stretch film also incorporates a tacky, cling-promoting surface so that successive wraps stick to each other and stay in place rather than unwinding.
The vast majority of stretch film is built on LLDPE, often blended with small amounts of other polyethylene resins or specialty cling additives, because LLDPE's combination of high elongation, good tensile strength, and puncture resistance makes it well-suited to being stretched dramatically without tearing while still protecting the load underneath. Both cast and blown processes are used to manufacture stretch film, with cast generally favored for higher clarity and tighter gauge control at high line speeds, and blown sometimes favored for higher puncture resistance and load-holding force at a given gauge.
Stretch film is specified by gauge, width, and stretch performance characteristics like ultimate elongation and containment force, and it's typically applied either by hand with a hand-held dispenser for lower-volume operations, or by automated stretch wrapping machines that apply consistent tension and wrap patterns for higher-volume shipping operations.
Glossary
Stretch Film
A highly elastic film, usually LLDPE-based, that is stretched around a load at the point of use and relies on elastic recovery to hold the load tightly together.
Example
A warehouse wrapping pallets of boxed goods before shipping will run machine-grade stretch film through an automated wrapper, relying on the film's elastic recovery and cling to keep the load secure through transit without any heat or adhesive involved.
Nuance
Stretch film performance is sometimes judged only by gauge, with buyers assuming a thicker film is automatically a stronger or more protective wrap, but a well-engineered thinner gauge stretch film, particularly one using higher-performance LLDPE blends, can deliver equal or better containment force than a thicker but less elastic film. Containment force and stretch percentage are better predictors of real-world load-holding performance than gauge alone.