Aluminum foil is the core barrier material in Tetra Pak aseptic cartons. It is mainly used for liquid foods such as UHT milk, juice, plant-based beverages, cream, and liquid seasonings to enable long-term storage at room temperature.
Common Technical Parameters
| Parameter | Specification |
|---|---|
| Thickness | 6–9 μm |
| Alloy | 8011 / 1235 |
| Temper | O (soft) |
| Pinhole Control | ≤ 100 holes/m² |
| Surface Tension | ≥ 32 dyn |
| Residual Oil | Low |
| Elongation | ≥ 2–3% |
Functions of Aluminum Foil in Tetra Pak Packaging
Although the aluminum foil layer is only 6–9 microns thick, it plays a critical role in the multilayer structure:
☑ Oxygen Barrier
Completely blocks oxygen, preventing fat oxidation and nutrient loss.
☑ Light Barrier
Protects vitamins and flavor compounds from degradation caused by UV and visible light.
☑ Moisture and Aroma Barrier
Prevents external odors from penetrating and preserves the product’s original flavor.
☑ Shelf-Life Extension
Combined with UHT sterilization, it allows products to be stored at room temperature for 6–12 months before opening.
Structure of Tetra Pak Aseptic Carton (6–7 Layers)
01. Polyvinylidene (PVDC)
- Serves as the innermost layer, in direct contact with food.
- Provides excellent oxygen barrier and moisture resistance, preventing contents from oxidation and spoilage.
02. Cellulose (Paperboard)
- The main structural layer, typically high-quality paperboard.
- Provides the rigidity and stiffness required to maintain the carton’s shape, and also acts as the printing substrate for product information.
03. Polyethylene (PE)
- Acts as an intermediate adhesive layer, bonding the paperboard core to the aluminum foil layer.
- Also provides additional moisture protection and sealing properties.
04. Aluminium (Aluminum Foil)
- The core barrier layer, critical for enabling “aseptic” and “ambient” storage.
- Provides 100% protection against light, oxygen, and moisture, effectively preserving the flavor, color, and nutrients of the contents while preventing microbial growth.
05. Polyethylene (PE)
- Serves as an outer adhesive layer, bonding the aluminum foil to the outermost PE film.
06. Polyethylene (PE)
- The outermost protective layer, offering good printability, abrasion resistance, and water resistance.
- Also functions as the heat-seal layer, enabling the carton to be formed and sealed during the packaging process.