Strapping material is the last line of defence between your packed load and a rejected delivery. The three options — polypropylene (PP), polyester (PET) and steel — differ enormously in strength, elongation, shock behaviour and cost. Choosing by habit rather than by load is the most common cause of avoidable transit damage.
| Property | PP (polypropylene) | PET (polyester) | Steel |
|---|---|---|---|
| Typical max load | ~200 kg | ~2,000 kg | 5,000 kg+ |
| Common widths | 5–19 mm | 12–19 mm | 13–32 mm |
| Elongation / recovery | High stretch, poor recovery | Elongates & recovers tension | None (rigid) |
| Shock behaviour | Stretches, can loosen | Absorbs impact | Snaps |
| Rust risk | None | None | High |
| Safety | Safe | Safe | Sharp cut edges — hazard |
| Relative cost | Lowest | Mid | Highest (plus seals) |
| Best for | Light cartons, bundling | Heavy & export loads | Very heavy/sharp, niche |
Polypropylene (PP): light loads and bundling
PP is a lightweight, flexible, low-cost plastic strap suited to light cartons and bundling up to around 200kg. It has high elongation but poor tension recovery — it stretches and can loosen — and lower tensile strength than PET or steel. It is the right, economical choice for light unitising, not for heavy pallets.
Polyester (PET): the modern replacement for steel
- Dynamic shock absorption: PET elongates slightly to absorb impact, then recovers tension — staying tight where steel would have snapped.
- Compression retention: as corrugated, textile or agricultural loads settle, steel goes slack but PET continuously recovers tension.
- Zero rust: PET is moisture-proof, protecting pharma, FMCG and automotive export loads from corrosion contamination on sea freight.
- Handles heavy loads up to ~2000kg — covering the vast majority of palletised industrial and export freight.
Steel: highest strength, biggest liabilities
Steel has the highest static breaking strength (5000kg+) and suits very heavy or sharp-edged loads. But it is rigid, so it snaps under the sudden shocks of road and sea transport instead of absorbing them; it rusts and stains cargo on long voyages; it needs crimped metal seals that top out near 60% joint efficiency; and its sharp cut edges are a genuine handling-safety risk. For dynamic transit, those liabilities usually outweigh its static strength.
The habit that costs money
Many Indian exporters still default to steel because "metal is strong". In transit, rigidity is the weakness: steel cannot stretch to absorb shock, so it snaps at the very moment the load needs it most. PET, applied at calibrated tension, holds where steel fails.
Matching material to machine
To get PET’s benefits it must be applied at precise, repeatable tension and sealed without metal clips. The ErgoPack 726X does both — digitally controlled tension from 400N to 2500N and a sealless friction-weld joint up to 90% efficiency on 12–16mm PP or PET strap. The GO and 700 route PP/PET around the pallet and let you finish with your own sealing tool.
Not sure whether your load needs PP or PET? Send us the weight and route.
Get a material recommendationFrequently Asked Questions
- PP vs PET vs steel — which strapping material should I use?
- Use PP for light cartons and bundling up to about 200kg, PET for heavy and export loads up to about 2000kg (it absorbs shock and resists rust), and steel only for very heavy or sharp loads above 5000kg where its rigidity and rust risk are acceptable. For most palletised industrial and export freight, PET is the best choice.
- Is PET strapping stronger than steel strapping?
- In static strength steel is higher, but for transit PET is functionally superior: it elongates to absorb the impacts that snap rigid steel, recovers its tension as loads settle, and does not rust. That makes PET safer and more reliable for dynamic transport loads up to around 2000kg.
- Why is PET better than steel for sea-freight exports?
- Steel rusts during long sea voyages, staining cargo and weakening the joint, and snaps under maritime shock. PET is moisture-proof and absorbs shock, so it keeps export loads secure and contamination-free — which is why it is the preferred export strap.
- Can the ErgoPack 726X run both PP and PET strap?
- Yes. The 726X runs both PP and PET in 12–16mm widths and seals them with a sealless friction weld up to 90% joint efficiency, with digitally controlled tension from 400N to 2500N.
Related guides
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