Stretch wrap is the polyethylene film used to secure unit loads on pallets.
Detailed Definition
Stretch wrap is usually linear low-density polyethylene film that is stretched as it is applied, so its elastic recovery holds cases tight to each other and to the pallet. Film thickness is commonly stated in gauge, where 100 gauge equals 1 mil (0.001 inch). It is applied by hand, with semi-automatic turntable or rotary-arm wrappers, or with fully automatic in-line stretch wrap machines, and machine films are often pre-stretched by powered rollers before reaching the load. Properly applied, stretch wrap keeps the unit load stable through transit.
Containment force matters more than thickness
What holds a load together is containment force: the squeeze the film exerts after it is stretched and applied. It comes from the film type, how far it is stretched, and how many layers are applied. A thinner high-performance film stretched correctly can hold better than a thicker film applied loosely. Many shippers measure containment force with a simple pull gauge to set their wrapper consistently.
Basic wrapping pattern
- Start with wraps around the base that cover the joint between the load and the pallet, tying the load to the pallet.
- Spiral upward with overlap between passes.
- Add extra wraps at the top to lock the top layer.
- Use corner boards on loads with sharp edges or light cartons.
Common mistakes
Wrapping only the product and not the pallet lets the whole load slide off the deck. Overstretching causes tears and loss of holding power, while understretching wastes film and leaves loads loose. Too many wraps add cost and plastic waste without adding much stability. Compare stretch wrap with banding or shrink wrap for heavy or irregular loads.
Authoritative Sources
- Material Handling Institute (MHI): the largest US trade association for material handling, logistics, and supply chain technologies.
Related Glossary Terms
Frequently Asked Questions
What is the difference between cast and blown stretch film?
They are made by different extrusion processes. Cast film is generally clearer, quieter as it unwinds, and has good cling on both sides, which makes it common for machine wrapping. Blown film is generally tougher and more resistant to punctures and tears, which helps on loads with sharp corners, though it is usually less clear and noisier. Many suppliers offer both, so test on your actual loads.
Can I use hand stretch film on a stretch wrap machine?
Usually not well. Hand films and machine films are made for different stretch levels, roll sizes and core sizes. Machine films, especially those used with powered pre-stretch, are designed to stretch much further before application. Hand film on a machine may tear or fail to reach the containment force you need, and machine rolls are typically too heavy to wrap by hand comfortably.