Stretch film and strapping are bought by the pallet, used by the kilometre and rarely specified properly. A cheaper film that tears on the wrapper, or a strap that looks the same but stretches more, shows up as leaning pallets, crushed cartons and loads that shift in the container. Because the cost per pallet is small, “same as last time” often becomes the specification, and a change of product is noticed only when a load fails.
This guide is for warehouses, factories and exporters buying stretch film and plastic strapping from makers in Vietnam and elsewhere in Asia. It explains what to put in the specification, how the relevant ASTM standards help, how to run a trial on your own equipment, and how to keep reorders consistent.
💬 Buying pallet wrap or strapping for several sites? Send us your wrapping machines, strapping tools, loads and monthly use, and we will look for makers in Asia that fit. Tell us what you wrap.
Know the job before you choose the film
Stretch film and strapping compact a unit load so it moves as one block; they are not, on their own, a means of securing the load in a container.
The IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (CTU Code) treats bundling, strapping and wrapping as an auxiliary measure of securing that should always be combined with direct securing or friction securing. It also warns that securing cargo to pallets by shrink foil wrapping is only sufficient if the foil is strong enough for that purpose, and that on a sea voyage repeated high loads in bad weather may fatigue the foil and reduce its securing capacity.
So the job of film and strap is to hold cartons to the pallet and to each other. How the pallet is then held in the container is covered in our guide to container loading and dunnage.
Before choosing a product, write down:
- Load: weight per pallet, height, carton type, whether the load is square or irregular, whether it has sharp corners.
- Equipment: hand wrapping, semi-automatic turntable, fully automatic line; manual, battery or pneumatic strapping tools, or a strapping machine.
- Route: inside the warehouse only, by truck, by container, cold store or tropical heat.
- Storage: indoors or outdoors, and for how long. ASTM D4649 is written for indoor environments and does not cover outdoor exposure.
Stretch film: what to put in the specification
Specify film by intended equipment, gauge, width, core, cling and the performance you will test, and ask the maker to put the same values on every reel label.
ASTM D4649-20(2025), Standard Guide for Use of Stretch Films and Wrapping Application, covers the selection, specification and use of stretch films for unitising, reinforcing and palletising for indoor environments, including storage and transport in warehouses, closed containers and transfer terminals. ASTM says it may be used between buyer and seller to arrive at purchase specifications. It also notes that the performance of stretch film may be negatively affected by extreme temperatures. It is a guide, not a pass-or-fail specification, so you still need to write your own values.
| Line in the specification | Hand film | Machine film | Why it matters |
|---|---|---|---|
| Use | Hand dispenser or by hand | Named wrapper type, with or without powered pre-stretch | Machine film must suit the pre-stretch system |
| Gauge | Stated in microns (or gauge) with tolerance | Same | Thinner film may tear on corners |
| Width and reel length | Matched to dispenser | Matched to carriage | Wrong width does not fit |
| Core | Inner diameter, wall, extended core for hand use | Inner diameter for the mandrel | Must fit equipment |
| Cling | One-side or two-side | One-side or two-side | Two-side cling can stick pallets together |
| Colour and print | Clear, black, coloured, printed | Same | Opaque film hides goods and labels from view |
| Process | Cast or blown | Cast or blown | Affects clarity, noise, puncture and tear behaviour |
Cast film is made by casting the melt onto chilled rollers; blown film is made by blowing a bubble. Each has its uses, and makers in Asia produce both. Instead of choosing on a label, ask for samples of each and test them on your loads.
Pre-stretch is where machine film saves or wastes money. A powered pre-stretch carriage stretches the film before it reaches the load, so each metre of reel covers more of the pallet. The film must be made to take that level of stretch without necking or breaking. Give the maker your wrapper’s pre-stretch setting and ask which film grade suits it.
Recycled content is another variable. Some films contain post-consumer or post-industrial recycled polymer, which can help with packaging-waste targets but may change performance. If your market sets a recycled-content rule for packaging, ask for a declaration and test the film on your own line.
PP and PET strapping
Choose polypropylene strap for light and medium bundling and polyester (PET) strap where you need higher strength and lower elongation, and specify width, thickness, break strength and the joint method together.
ASTM D3950-23, Standard Specification for Strapping, Nonmetallic (and Joining Methods), covers nonmetallic strapping and joining methods for closing, reinforcing and bundling shipments, unitising, palletising and bracing for car and truck loading. ASTM classifies the strapping into five types according to the material used, and the specification checks properties such as breaking strength and elongation. Like D4649, it uses inch-pound units as the standard values.
| Feature | PP strap | PET strap | Steel band |
|---|---|---|---|
| Typical use | Cartons, light bundles, closing boxes | Heavy unit loads, bricks, timber, metal products | Very heavy, rigid loads |
| Elongation | Usually higher than PET; check test values | Usually lower than PP; check test values | About 0.3 % at MSL (CTU Code) |
| Tension after settling | Check on a trial load | Check on a trial load | Sensitive to losing pre-tension (CTU Code) |
| Joining | Heat or friction weld, or buckles | Friction weld, seals or buckles | Seals and crimps |
| Handling risk | Low | Low | Sharp edges; can whip when cut |
On steel band, the CTU Code gives a useful contrast. It says the low flexibility of steel band, at about 0.3 % elongation when loaded to its maximum securing load, makes it sensitive to losing pre-tension if the cargo shrinks or settles, and that national restrictions on steel band use in road or rail transport should always be considered. For heavy unit loads, compare the maker’s test values for PET strap and steel band and try both on your loads.
In the specification, write:
- material (PP or PET), width and thickness, embossed or smooth;
- breaking strength and elongation at break, with the test method;
- core size, coil length and coil weight, matched to the dispenser or machine;
- joint method and, for seals or buckles, their size and grade;
- colour and any printing.
The joint is usually the weak point. A strap with a high breaking strength joined by a poor weld or the wrong seal will fail at the joint first. Ask the maker for the joint efficiency on the tool or machine you use, or test it yourself.
💬 Comparing strapping from two or three makers? We can collect samples on one specification, arrange break and elongation tests and compare the results with you before you switch. Ask about strapping trials.
Run a trial on your own line
Test film and strap on your own equipment and your own loads before switching supplier, and record the settings that worked.
Data sheets are measured in a laboratory. Your wrapper, your load and your climate may give different results. A simple trial plan:
- Same loads. Wrap or strap a set of identical pallets with the current product and the candidate.
- Same machine settings. Record pre-stretch, number of wraps, top and bottom wraps, tension and strap pattern.
- Measure use. Weigh the film or count the strap used per pallet.
- Check the result. Look for tears, loose tails, necking, film sticking to neighbouring pallets, crushed carton edges and strap slack after a few days.
- Handle and move. Lift, drive, and if possible send a test pallet on a real route.
- Write it down. The approved product, settings and pattern become your specification.
ASTM also publishes a range of test methods for stretch films under the same subcommittee as D4649. If you need a measured comparison, ask a test laboratory which ASTM or ISO methods suit your question.
Reorders and consistency
Keep the approved specification, the sample and the reel or coil label, and quote them on every reorder so the maker cannot change the product without telling you.
- Labels. Ask for a label on each reel or coil showing product code, gauge or size, length, net weight and batch.
- Weight check. Weigh a sample of reels or coils on arrival. A short reel looks the same until it runs out early.
- Storage. Store film and strap indoors, away from heat and sunlight; the ASTM guide notes that extreme temperatures can affect stretch film.
- Inspection. Check labels, weights and appearance against the approved sample before shipment. Our note on pre-shipment inspection and AQL explains sampling.
- Pallets. If the film and strap ship on wooden pallets across a border, those pallets fall under ISPM 15; see our guide to export pallets and ISPM 15.
Consumables are a good candidate for consolidation with other factory supplies. Our guide to consolidating Asian suppliers in one shipment explains how.
Frequently asked questions
1. Is stretch film enough to secure pallets in a container?
No. The CTU Code treats wrapping and strapping as auxiliary measures that should be combined with blocking, lashing or friction securing.
2. Should I buy cast or blown film?
Both are used for pallet wrapping. Ask for samples of each in the gauge you need and test them on your loads and equipment.
3. Is PET strap a replacement for steel band?
It can be, depending on the load. The CTU Code notes that steel band, with very low elongation, can lose pre-tension when cargo settles. Compare test values, try PET on your own load and check local rules for securing.
4. What standard covers plastic strapping?
ASTM D3950-23 is the US specification for nonmetallic strapping and joining methods. It classifies strapping into five types by material. Other markets may use their own standards; ask the maker which one its test values refer to.
5. Can you source a brand we already use?
We can search for the products you name, and for equivalents to your specification, from makers in Vietnam and Asia. We are not an authorised distributor of any brand, and we test equivalents before you switch.
Summary
Specify film and strap against your own equipment and loads, use ASTM D4649 and D3950 as the vocabulary, prove the choice in a line trial and reorder on the approved specification.
Sunsho Trade is a trading company. For stretch film and strapping we look for and vet makers in Vietnam and Asia, collect quotations on one specification, arrange samples and tests, inspect batches, and ship them with your other plant consumables.
💬 Ready to source wrap and strapping? See our industrial packaging and logistics materials service, or send us your current specification. For other plant supplies, start from industrial sourcing.
Sources
Checked on 27 October 2026.
- ASTM D4649-20(2025), Standard Guide for Use of Stretch Films and Wrapping Application: https://store.astm.org/d4649-20r25.html
- ASTM D3950-23, Standard Specification for Strapping, Nonmetallic (and Joining Methods): https://store.astm.org/d3950-23.html
- IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (CTU Code), MSC.1/Circ.1497 (16 December 2014), Annex 7, subsections 2.3.7 and 2.4.16 and section 4.1: https://www.imo.org/en/OurWork/Safety/Pages/CTU-Code.aspx