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Barrier Layers in Laminated Film: PET, Aluminum, VMPET and PE Explained
2025-10-27
A laminated film is a stack of layers, each doing one job: carrying print, blocking moisture, oxygen or light, or sealing. Choosing a structure means deciding which layer takes each role.
The three roles
- Print layer: carries artwork and adds stiffness. Usually PET or BOPP.
- Barrier layer: blocks light, moisture and oxygen. Aluminum foil, VMPET or VMCPP.
- Heat seal layer: forms the seal to itself or to a lidding. Usually PE or CPP.
Reference densities
| Material | Role | Density |
|---|---|---|
| PET | Print layer | 1.40 g/cm³ |
| BOPP | Print layer | 0.90 - 0.93 g/cm³ |
| Aluminum foil | Barrier layer | 2.70 g/cm³ |
| VMPET | Barrier layer | 1.40 g/cm³ |
| VMCPP | Barrier and seal | 0.90 g/cm³ |
| PE | Heat seal layer | 0.92 g/cm³ |
| CPP | Heat seal layer | 0.90 - 0.91 g/cm³ |
Designing a structure
Start from the product. A hygroscopic powder needs an aluminum or metallized barrier, a light-sensitive formulation needs an opaque or metallized layer, and a single-serve sachet needs a low-temperature seal that runs at line speed.
Next steps
We convert structures such as PET/AL/PE, PET/VMPET/PE and BOPP/VMCPP in a D-class cleanroom. See Composite Laminated Film or request a quote.
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