Stretch film basics
One-sided vs two-sided cling stretch film
Written by Öncümak Engineering Team2 min read
In short
Cling is what makes the layers of stretch film stick to each other. It can be built into one side of the film, both sides, or both sides at different levels. One-sided cling film keeps neighbouring pallets from sticking together, but the cling side must face the load. You can find the cling side by sticking the film to itself.
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Stretch film basics
- What is stretch film?
- Hand vs machine stretch film: what's the difference?
- What is pre-stretched film?
- What is coreless stretch film?
- PE stretch film vs PVC cling film: what's the difference?
- Is stretch film recyclable?
- Where is slit stretch film used?
- Black and coloured stretch film: what is the colour for?
- Why stretch film tears, breaks or does not cling, and how to fix it
- How to wrap a pallet with stretch film
- How many pallets does a roll of stretch film wrap? Film use and cost per pallet
- Stretch film vs shrink film: what is the difference?
- How to use coreless stretch film: handles, dispensers and wrapping machines
- When is pre-stretched film not the right choice?
- How to measure the pre-stretch on a pallet wrapper
- Stretch hood vs stretch wrap: which one fits your pallets?
- How wrapped pallets are tested: load stability and EUMOS 40509
- Recycled content (PCR) stretch film and plastic packaging taxes
- How to store stretch film: temperature, humidity and shelf life
- One-sided vs two-sided cling stretch film
- UV-resistant stretch film for outdoor storage
- Stretch film for moving house: how to wrap furniture and boxes
- Slit stretch film, strapping or tape: which one for bundling?
- Which width for which product? Slit stretch film rolls and dispensers
Advice & investment
- How to choose a stretch film rewinding machine
- How to calculate stretch film roll length and weight
- Stretch film thickness: what do the microns change?
- How much does a stretch film rewinding machine produce?
- How to start a stretch film rewinding business
- How to choose jumbo rolls for stretch film rewinding
- What determines the price of stretch film?
What cling is
Cling is the "stickiness" of stretch film: how strongly one layer holds on to the layer beneath it. It is what keeps the wraps together without tape or glue. Lantech, a maker of pallet wrappers, describes it as coming from a tackifier, a bonding agent added as a layer to the film during extrusion.
Where cling comes from
- PIB: published research describes polyisobutylene (PIB) as the most widely used cling agent in stretch films. It moves to the film surface after production, so cling builds up over time; one study found that cling forces reached their maximum about two weeks after the film was made.
- Cling polymers: according to a 2015 Plastics Technology article written with a resin maker, the industry moved from PIB, which is a sticky liquid that is hard to dose, to metallocene elastomers and then to propylene-based elastomers in the cling layers, which give comparable cling at lower amounts.
One-sided, two-sided and differential cling
Lantech lists three ways to build cling into a roll:
| Type | What it means |
|---|---|
| One-sided cling | One side clings, the other side slips |
| Two-sided cling | Both sides cling at the same level |
| Differential cling | Both sides cling, one more than the other |
Why one-sided cling exists
When film clings on the outside too, wrapped pallets standing side by side can stick or drag against each other. A 1985 patent for one-sided cling stretch wrap (US4518654A) describes exactly this "serious and expensive problem" in handling and transport. With a slip outer side, wrapped loads can slide past each other without sticking or tearing the film.
One-sided cling is the safer choice when pallets stand close together in trucks or warehouses. Lantech notes that most LLDPE films already have little enough cling on the outside that loads slide over each other; if loads must slide easily, a film with a higher-slip outer side helps.
Which side faces the load?
The cling side must face the load; POLIFILM's application advice says so plainly. On a one-sided roll the cling side usually faces inwards, towards the core, and many producers print arrows on the core to show the operator how to load the roll.
How to check: pull back some film and press one side against itself. If it sticks, that is the cling side.
What it means for rewinding
The cling type comes with the jumbo roll; a rewinding machine does not change it. Know which side of the jumbo roll clings, check the finished rolls with the self-stick test, and mark the cores so that your customers load them correctly. Cling that varies from one jumbo roll to the next makes tension harder to set; see how to choose jumbo rolls.
Sources(5)
- Seibert, A., Lantech (2026). What is tackifier and why is it in stretch film?
- Patent US4518654A (1985). One-sided cling stretch wrap
- Polifilm. Application advice for stretch films
- Cabrera, G., Pichon, G., Maazouz, A., Lamnawar, K. (2021). Rheology and tribology: investigating the migration of small molecules in recycled agricultural waste multilayer films. ESAFORM 2021.
- Plastics Technology (2015). What You Need to Know to Make World-Class Stretch Film. With contributions from ExxonMobil Chemical, Cloeren and Windmöller & Hölscher.
Related machines
- What is stretch film?Stretch film is a thin, highly elastic plastic film, usually made from LLDPE, that is stretched around goods and holds them together as it tries to return to its original length. It keeps pallets stable, clean and tamper-evident during storage and transport.
- Hand vs machine stretch film: what's the difference?Hand stretch film comes in small, light rolls that people apply by hand; machine stretch film comes in larger, heavier rolls made for pallet wrapping machines. Both are usually LLDPE; the differences are roll size, core, how far the film is stretched and how it is applied.
- What is pre-stretched film?Pre-stretched film is stretch film that has already been stretched, typically by 300–500%, during rewinding, before it reaches the user. It is thinner and lighter, takes far less effort to apply and uses less film per pallet, but it has little stretch left, so it suits standard loads better than very sharp or irregular ones.
- What is coreless stretch film?Coreless stretch film is wound without a paper core, so the whole roll is usable film. It removes the cost and waste of cores, makes rolls lighter to ship and to dispose of, and is usually applied with a simple reusable handle or dispenser.
- PE stretch film vs PVC cling film: what's the difference?PE stretch film is a polyethylene film made to secure pallets and bundles. PVC cling film is a thin, clear film made from polyvinyl chloride, used mainly to wrap food. They are different materials for different jobs, and PVC cling film, as a food-contact material, has to meet food-contact legislation.
- Is stretch film recyclable?Yes. Stretch film is polyethylene, marked with recycling code 4 (LDPE), and can be recycled where used film is collected clean and separately from other materials. New packaging rules in the EU and Türkiye push in the same direction: less packaging, recyclable packaging and responsibility for the packaging you place on the market.
- Where is slit stretch film used?Slit stretch film is ordinary stretch film cut into narrow rolls. Narrow rolls are easier to handle on small, long or round products (profiles, cables, hoses, pipes) and are used for bundling and surface protection, from building-product plants to car workshops.
- Black and coloured stretch film: what is the colour for?Most stretch film is clear, but black, white and coloured films exist for good reasons: hiding and protecting the load, colour-coding pallets or showing a brand. Colour also affects how easily the film can be recycled.
- Why stretch film tears, breaks or does not cling, and how to fix itMost film breaks start at the load (sharp corners and edges), in the roll (nicks, damaged edges, flaws) or in the settings (too much force or pre-stretch). Poor cling usually comes from cold, very fresh or badly stored film. Check the load, the roll and the settings, in that order, before you change the film.
- How to wrap a pallet with stretch filmFasten the film to the pallet, wrap the base several times so the load is locked to the pallet, spiral up with an even overlap and finish with extra wraps at the top. The holding force comes from the film's tension and the number of layers, so the right number of wraps depends on the load. For loads that travel by road, machine wrapping gives far more holding force than wrapping by hand.
- How many pallets does a roll of stretch film wrap? Film use and cost per palletThe fastest way to find out is to weigh: weigh a roll, wrap ten pallets, weigh it again and divide. To estimate before you wrap, multiply the number of wraps by the pallet's perimeter, divide by how far the film is stretched, and convert metres to grams. Compare films by cost per pallet, not by price per roll.
- Stretch film vs shrink film: what is the difference?Stretch film is applied cold: it is stretched around the load and holds it as it tries to contract. Shrink film is applied loose and then heated, so that it shrinks tightly around the product. Stretch film is the usual choice for pallets; shrink film is used for retail packs and for some pallet loads such as bricks, where it is applied as a hood and heated.
- How to use coreless stretch film: handles, dispensers and wrapping machinesA coreless roll has a hole where the core would be. By hand, it is used with a reusable handle or dispenser that fits into that hole, so the roll is easy to hold and its last metres can be used too. On pallet wrapping machines, a reusable adapter takes the place of the core. Match the handle or adapter to the roll's inner diameter and the whole roll can be used.
- When is pre-stretched film not the right choice?Pre-stretched film saves film and effort when pallets are wrapped by hand or on simple wrappers. It is not the right tool for holding heavy or unstable loads together by hand, and it is not meant for wrappers with powered pre-stretch, which stretch conventional machine film themselves. Choose by the load, the wrapping method and the cost per pallet.
- How to measure the pre-stretch on a pallet wrapperPre-stretch is given as the percentage by which the film gets longer: at 250%, one metre of film from the roll becomes 3.5 metres. To check it, draw two marks 10 cm apart on the film before it is stretched and measure them again afterwards. Measure whenever you change the film or the settings: the stretch decides how much film each pallet uses.
- Stretch hood vs stretch wrap: which one fits your pallets?A stretch hood is a film sleeve, smaller than the load, that a machine stretches and pulls over the pallet; stretch wrap is film wound around the load in layers. Hoods are fast, fully automatic and protect well against the weather, but each load size needs its own hood. Stretch wrap adapts to almost any load, by machine or by hand.
- How wrapped pallets are tested: load stability and EUMOS 40509A wrapped pallet is tested by pushing it sideways with a known force, usually 0.5 g, and measuring how far it deforms. The European guidelines describe a tilt test and two acceleration tests; the pallet-level acceleration test follows EUMOS 40509. A pallet passes if it springs back within set limits and nothing is damaged.
- Recycled content (PCR) stretch film and plastic packaging taxesStretch film counts as plastic packaging, so plastic packaging taxes and recycled-content rules apply to it. The UK taxes plastic packaging with less than 30% recycled content, Spain taxes the non-recycled plastic in single-use packaging, Türkiye charges a recovery contribution per kilogram, and from 2030 the EU will require 35% post-consumer recycled content in most plastic packaging. Check the details for your country with an advisor.
- How to store stretch film: temperature, humidity and shelf lifeStore stretch film indoors, away from sunlight and moisture, at about 10–30 °C and 25–60% relative humidity, and use it within a year. Let it adapt to the room where it will be used for at least 24 hours. Cold film is stiffer and stretches less, and very fresh film may not cling fully yet.
- UV-resistant stretch film for outdoor storageStandard stretch film is not UV-resistant: in sunlight it yellows, weakens and loses its cling and stretch. UV-stabilised film contains an additive that slows this down, and producers state protection for about 9 to 12 months outdoors. Clear UV film protects the film itself; to protect sun-sensitive goods too, use an opaque UV film.
- Stretch film for moving house: how to wrap furniture and boxesStretch film is one of the handiest materials for a move: it keeps drawers and doors shut, bundles loose parts and protects surfaces from dust and scratches. Clean and dry everything first, and never wrap wood, antiques, leather or upholstery directly: put blankets or paper underneath so that moisture is not trapped.
- Slit stretch film, strapping or tape: which one for bundling?For light bundling, a narrow roll of stretch film is often the simplest choice: it clings to itself, covers and protects the surface and leaves no adhesive residue. Straps are cheap and very good at stopping loads from tilting, but they need corner protection and plastic straps lose tension over time. Tape closes boxes but can leave residue on the goods. Heavy loads often need film and straps together.
- Which width for which product? Slit stretch film rolls and dispensersSlit rolls are cut from a jumbo roll into equal widths: a 50 cm jumbo roll gives 25, 16.6, 12.5 or 10 cm rolls and so on down to 5 cm. As a rule, the thinner and rounder the item, the narrower the roll. A handle or dispenser that fits the roll's core makes narrow film faster and easier to apply.