Stretch wrapping secures a pallet load by winding elastic polyethylene film around it under tension, so that the film's elastic recovery squeezes the goods into one stable unit. A good wrap is defined by containment force (the squeezing force at any point of the load), by locking the film to the pallet, and, in Europe, by proving load rigidity with the EUMOS 40509 test method, not by how much film is used.
How stretch film works
Stretch film is almost always made from linear low-density polyethylene (LLDPE), a copolymer of ethylene with an alpha-olefin such as butene, hexene or octene. Higher alpha-olefins improve elongation and puncture resistance. Film can typically elongate several hundred percent before breaking but is used at a lower stretch, often in the range of 100–300%, so that it keeps enough elastic memory to pull back on the load.
When film is stretched and wrapped around the load, it tries to return to its original length. That recovery produces wrap force. Each layer adds its own force, so:
Containment force ≈ wrap force per layer × number of layers at that point.
This simple relationship is why two loads that use the same amount of film can be secured very differently: one with a few tight layers, the other with many slack ones.
Film types
| Film type | How it is made | Strengths | Limitations |
|---|---|---|---|
| Cast film | Extruded through a flat slot die onto chilled rollers | Clear, quiet unwinding, consistent gauge, economical | Less cling and puncture resistance than blown film |
| Blown film | Extruded through a ring die and inflated into a bubble, air-cooled | Tough, high cling and puncture resistance | Slower production, more gauge variation, higher cost |
| Pre-stretched film | Stretched at the factory and rewound | Light to apply by hand, low film weight | Little remaining stretch, so limited containment |
| Nano or multilayer film | Many very thin co-extruded layers | High strength at lower thickness | Needs a capable machine to use its stretch potential |
| Vented film | Perforated | Lets produce or warm goods breathe | Lower containment than solid film |
| Coloured or UV film | Pigmented or stabilised | Product concealment, outdoor storage | Higher cost; coloured film can complicate recycling |
Hand film is supplied on narrow rolls light enough to hold; machine film comes on heavier rolls designed for a powered carriage. The film supplier's data sheet states thickness, recommended pre-stretch and maximum elongation.
Hand wrapping vs machine wrapping
Hand wrapping
Hand wrapping needs no investment and suits low volumes, but the operator can only stretch film a little, tension varies from layer to layer, and walking backwards around pallets is a recognized injury risk. Hand-held dispensers with brakes or extended cores improve tension and reduce strain.
Machine wrapping
Machines apply consistent tension and, with powered pre-stretch, stretch the film between two rollers turning at different speeds before it reaches the load. A pre-stretch of 200% means one metre of film becomes three metres on the load, which reduces film consumption and gives consistent wrap force.
| Machine type | How it works | Typical use |
|---|---|---|
| Turntable | Pallet rotates on a turntable; film carriage moves up and down a mast | Most common semi-automatic choice for stable loads |
| Rotary arm | Load stays still; arm carries the film around it | Light, tall or unstable loads; high-speed lines |
| Rotary ring | Horizontal ring rotates around a static load | Very high throughput automated lines |
| Orbital (horizontal) | Film passes through a ring around goods moving horizontally | Long products, profiles, doors, boards |
| Robot (self-propelled) | Small battery vehicle drives around the pallet | Oversized or heavy loads, occasional use |
Best practice for a stable wrap
- Lock the film to the pallet. Start with several revolutions at the base and roll the film edge into a cable or "rope" that grips the pallet blocks or deck. A load that is wrapped only above the pallet can slide off it as one unit.
- Overwrap the top tier. Extend the film slightly above the top layer to hold the upper cartons down, or use a top sheet.
- Target containment force, not film weight. Define a force for each load type, set the machine accordingly and check it regularly with a containment force tool.
- Choose pre-stretch to suit the load. Fragile or crushable goods need lower wrap force; heavy, dense goods need more layers rather than excessive tension.
- Watch corners. Sharp corners puncture film; corner boards protect both product and film.
- Avoid gaps and overhang. Cartons overhanging the pallet edge weaken the wrap and the load. Build the load square to the pallet footprint.
- Inspect the result. Look for tears, loose tails, bulging film and whether the load moves when pushed.
Stretch wrap is containment, not vehicle load securing. On a truck the wrapped unit still needs to be blocked or lashed as described in load securing for palletised cargo, and tall loads must also meet the limits in pallet stacking rules.
Testing load stability: EUMOS 40509
EUMOS, the European Safe Logistics Association, publishes EUMOS 40509, a test method for load unit rigidity (current edition 2020, first edition 2012). A complete wrapped or hooded load unit is subjected to a defined horizontal acceleration on a test rig, and its permanent and elastic deformation is measured against limits. A load unit that passes can be regarded as rigid when calculating cargo securing.
The method matters legally: Directive 2014/47/EU on technical roadside inspection of commercial vehicles lists EUMOS 40509 under transport packaging in its cargo securing annex, alongside EN 12195-1 for lashing calculations. Road inspectors can therefore refer to it when judging whether a palletised load was secure.
A related method, EUMOS 40513, measures the forces exerted by stretch film and stretch hoods at the edges of a load.
Stretch hood and other alternatives
Stretch hooding pulls a tubular film over the load from above and lets it contract, covering five sides and protecting against rain and dust. It suits high-volume, uniform loads such as bagged products, building materials and beverages. Shrink hoods use heat instead of elasticity.
Other options include strapping (for heavy, rigid goods like timber or bricks), adhesive between layers and reusable wrap systems in closed loops. The choice also affects automated warehouses, where loose film tails can trip conveyor photocells.
Cost and sustainability
Film cost is driven by film weight per pallet, which depends on pre-stretch, number of layers and film gauge. Machines with high powered pre-stretch often cut film use substantially compared with hand wrapping, which is why film per pallet (grams) and containment force are the two numbers worth tracking together.
Used stretch film is clean LDPE and is widely recycled when collected separately, while contaminated or coloured film is harder to recover. In the EU, transport packaging is covered by the Packaging and Packaging Waste Regulation, Regulation (EU) 2025/40; see EU PPWR and pallets for the implications for pallet wrapping.
Frequently asked questions
What is containment force in stretch wrapping?
It is the total squeezing force the film exerts on the load at a given point, equal to the wrap force of each layer multiplied by the number of layers. It is the main specification for a secure wrap.
What is the difference between cast and blown stretch film?
Cast film is extruded through a flat die and chilled on rollers, giving a clear, consistent and economical film. Blown film is inflated as a bubble and air-cooled, giving more cling and puncture resistance at a higher cost.
What does pre-stretch mean?
Pre-stretch is stretching the film before it touches the load, either at the factory or by powered rollers on the machine. At 200% pre-stretch, one metre of film covers three metres of load.
Is stretch wrapping enough to secure a load on a truck?
No. Wrapping holds the goods together as a unit, but the unit still has to be secured to the vehicle by blocking, lashing or friction measures that withstand the accelerations required by law.
Sources
- Stretch wrap — Wikipedia
- EUMOS Standards — EUMOS, the European Safe Logistics Association
- Directive 2014/47/EU, Annex III: Cargo securing — legislation.gov.uk (EU directive text)
- Containment Force Tool — Lantech