Flexible packaging aluminium foil refers to aluminium foil used in flexible packaging. It is usually not used alone, but laminated with other materials (such as PET, PE, PP plastics or paper, and sometimes metallized film) to form a multi-layer flexible film. Its characteristics include:
- Flexible and lightweight
- Barrier properties (against gases, moisture, and light)
- Heat-sealable and/or formable into pouches, sachets, or stand-up bags
The thickness of Flexible Packaging Aluminium Foil is usually between 0.006mm and 0.2mm. The common thickness used for packaging is 0.006mm–0.009mm (i.e., 6–9 microns), which is extremely thin and soft.
Flexible packaging aluminium foil is a metallic foil material typically less than 0.2 mm thick, widely used in food, pharmaceutical, and new energy fields. It offers excellent barrier properties, moisture resistance, and high-temperature performance.
Features of Flexible Packaging Aluminium Foil
- Gas Barrier: Aluminum foil effectively blocks oxygen, air, and other gases, preventing the oxidation or deterioration of the packaged contents.
- Water Vapor Barrier: Aluminum foil can block water vapor, keeping the packaged contents dry.
- Light Barrier: Aluminum foil blocks light, preventing damage to the contents caused by exposure to light.
- Mechanical Performance and Structural Rigidity: Aluminum foil provides the necessary mechanical performance and structural rigidity to maintain the shape and stability of the packaging (e.g., maintaining folds).
Specifications of Flexible Packaging Aluminium Foil
- Alloy: Common alloys include 1235, 8011, 8079.
- Temper: Usually "O" (soft annealed), suitable for lamination.
- Thickness: Depending on barrier requirements, the range varies widely — for example, many flexible packaging foils typically have a thickness of 0.006 mm (6 microns) to 0.03 mm (30 microns).
- Width: Coil width ranges from about 200 mm to over 1, 600 mm, depending on application.
- Typical lamination substrates: PET/AL/PE, BOPP/AL/PE, PA/AL/PE, etc.
- Surface finish: One bright side, one matte side; embossed or print-friendly surfaces can be provided if required.
| Commodity | Alloy | Temper | Thickness (mm) | Width (mm) | Coil ID (mm) |
| Aluminum flexible packing foil | 8079 | O | 0.0055-0.009 | 200-1500 | 76/152 |
| 1235 | O | 0.0055-0.009 | 200-1500 | 76/152 |
Laminated Structure of Flexible Packaging Aluminium Foil
Aluminium foil is rarely used alone because it is prone to creasing, potential pinholes (though very low probability), and it cannot be heat-sealed by itself. Therefore, it is usually laminated with plastics (such as PET, PE, PP, NY) or paper.
- Outer layer: Usually PET (polyester) or NY (nylon), providing mechanical strength, abrasion resistance, printability, and stiffness.
- Middle layer: Aluminium foil, providing the core barrier function.
- Inner layer: Usually CPP (cast polypropylene) or PE (polyethylene), providing heat sealability and serving as the sealing layer that directly contacts the contents.
- Food packaging: Aluminium foil is laminated with PE and nylon to form a “plastic–aluminium–plastic” three-layer structure, used for retort pouches and coffee capsules.
- Battery soft pack: Nylon layer – aluminium foil layer – heat-sealing layer (CPP), with aluminium foil serving as the middle barrier layer to prevent electrolyte leakage.
Common examples:
- Pharmaceutical blister packaging: PVC/aluminium foil or PVDC/aluminium foil
- High-temperature retort pouch: PET/aluminium foil/CPP
- Milk powder packaging: Paper/PE/aluminium foil/PE
- Beverage lid material: Paper/PE/aluminium foil/heat sealant
Selection of Aluminium Alloys for Flexible Packaging
Commonly used aluminium alloys for flexible packaging mainly include the 1000 series and 8000 series, designed to meet various application needs. These alloys offer excellent formability and adaptability, fulfilling diverse performance requirements in flexible packaging.
Flexible Packaging Aluminium Foil 8011
- Features: 8011 aluminium foil has excellent formability, toughness, and barrier properties. Its strength and stability make it suitable for a wide range of flexible packaging applications, including food and beverage packaging. 8011 aluminium foil is especially suited for packaging that requires good moisture, gas, and light barrier properties.
- Applications: Commonly used in food packaging, pharmaceutical packaging, and other flexible packaging fields that require high barrier properties.
Flexible Packaging Aluminium Foil 8079
- Features: 8079 aluminium foil has excellent ductility and tear resistance while maintaining good barrier properties. It is particularly suitable for flexible packaging applications that require higher mechanical performance.
- Applications: Widely used in pharmaceutical packaging, food packaging, cigarette packaging, and other areas that demand high strength and good barrier properties.
Flexible Packaging Aluminium Foil 1235
- Features: 1235 aluminium foil offers exceptional flexibility and formability, making it suitable for applications requiring high printing performance. Its barrier properties are slightly less than those of 8011 and 8079, but it still effectively blocks moisture and air.
- Applications: Mainly used in food packaging, candy packaging, and some flexible packaging fields that require high-quality printing.
8011 aluminium foil is ideal for high barrier requirements, 8079 aluminium foil for high mechanical strength needs, and 1235 aluminium foil for applications requiring excellent printing performance.
Flexible Packaging Aluminium Foil Chemical Composition
| Elements | Composition /% | ||
| 1235 | 8011 | 8079 | |
| Si | 0-0.65 | 0.50-0.90 | 0.05-0.30 |
| Fe | 0-0.65 | 0.60-1 | 0.70-1.30 |
| Cu | 0-0.05 | 0-0.10 | 0-0.05 |
| Mn | 0-0.05 | 0-0.20 | - |
| Mg | 0-0.05 | 0-0.05 | - |
| Cr | - | 0.05 | - |
| Zn | 0-0.1 | 0-0.10 | 0-0.10 |
| Ti | 0-0.06 | 0-0.08 | - |
| V | 0-0.05 | - | - |
| Al | Rem | Rem | Rem |
Mechanical Properties of Flexible Packaging Aluminium Foil
| Alloy | Temper | Thickness /mm | Tensile strength /MPa | elongation after break /%, (not less than) | |
| A50mm | A100mm | ||||
| 1235 | O | 0.0060 - 0.0090 | 45-95 | 0.5 | |
| 8011 8079 | 50-105 | 1.0 | |||
Advantages of Flexible Packaging Aluminium Foil
- Barrier against gas, moisture, light, and aroma: Since aluminium is a metal foil, it provides significantly higher barrier properties compared to most plastics.
- Mechanical/structural function: Although aluminium foil is thin, it provides certain structural rigidity and dead-fold properties, ideal for packaging and complex shapes.
- Heat resistance/thermal performance: The thermal conductivity and reflectivity of aluminium make it advantageous in certain packaging applications (e.g., heat-sealable bags, cook-in or retort pouches).
- Printability/appearance: Aluminium foil supports high-quality printing and can undergo surface treatment to achieve a premium packaging appearance.
- Lightweight: As a thin foil layer, it provides strong barrier protection while remaining very light in weight.
Applications of Flexible Packaging Aluminium Foil
Food and Beverage Packaging
Food packaging aluminium foil typically ranges from 0.006–0.012mm thick to ensure pinhole-free performance and low water vapor transmission rate. It is commonly used for yogurt lids, snacks, confectionery, dairy products, coffee, and tea — helping preserve freshness, aroma, and protection against light and oxygen damage.
Food Packaging
Use: Packaging for foods such as chocolate and cheese.
Advantages: Preserves freshness and flavor, blocking air and moisture.
Candy Packaging
Use: Packaging for various candies.
Advantages: Maintains the freshness of the candy and prevents spoilage.
Butter Packaging
Use: Packaging for butter.
Advantages: Moisture and light resistance, preserving the quality and taste of butter.
Household Aluminium Foil
Use: Multipurpose aluminium foil for household kitchens.
Advantages: Used for cooking, storing, and wrapping food.
Pharmaceutical Packaging
Pharmaceuticals require high barrier performance. Aluminium foil is commonly used in blister packaging (PTP), as well as unit-dose packaging for tablets and capsules. Pharmaceutical foil bags are used for granules, powders, and sterile barrier packaging for medical devices.
Pharmaceuticals
Use: Packaging and sealing for pharmaceuticals.
Advantages: Protects medicines from moisture, light, and contaminants.
Industrial Applications
New Energy Battery Field (Lithium Battery Packaging)
- Application: Specially designed for soft-pack lithium battery sealing, serving as a core component of pouch-type battery casings.
- Key specification: Commonly uses 8021 alloy aluminium foil.
- Core advantages: Achieves significant weight reduction—up to 30% lighter than traditional steel-shell batteries; provides high safety and improved stability and protection during battery operation.
Cable Industry
- Application: Used in insulation layers and electromagnetic shielding structures of cables and motors.
- Core advantages: Offers excellent dielectric performance ensuring insulation reliability; also provides outstanding electromagnetic shielding to minimize signal interference or external electromagnetic impact on cables/motors.
Capacitor Manufacturing
- Application: Serves as a key material in capacitor production, forming part of the electrode or insulation structure.
- Core advantages: Provides necessary electrical insulation for capacitor operation, maintains long-term performance stability, and extends product lifespan.
Transformer Industry
- Application: Used for internal insulation isolation and external electromagnetic shielding protection in transformers.
- Core advantages: Effectively blocks external electromagnetic interference signals, ensuring stable transformer operation, reliable power supply, and equipment safety.
Construction and Insulation
Insulation and Waterproofing
Use: Insulation and waterproofing treatment for panels, asphalt membranes, rock wool, cork, double glazing, and other materials.
Advantages: Provides excellent insulation and waterproofing properties, enhancing the energy efficiency and durability of buildings.
Other Packaging Applications
Cigarette Foil
Use: Packaging for cigarettes.
Advantages: Moisture and oxidation resistance, maintaining the freshness of cigarettes.
Retort Pouches
Use: Retort pouches for food and pharmaceutical packaging.
Advantages: Resistant to high temperatures and provides barrier properties suitable for high-temperature processing.
Composite Flexible Packaging
Use: Flexible packaging for various composite materials.
Advantages: Combines the benefits of aluminium foil with other materials, enhancing the overall performance of the packaging.
Aluminium foil in these applications is typically combined with materials like plastic and paper to enhance its physical strength and suitability.
Limitations of Flexible Packaging Aluminium Foil
- Higher cost: More expensive than pure plastic packaging.
- Opaque: Consumers cannot directly see the contents.
- Lower flexibility: Repeated bending may cause pinholes or cracks, damaging barrier properties.
- Recycling challenge: Laminated packaging materials are difficult to separate, making recycling more complex than single-material structures.
The aluminium foil layer in composite packaging is extremely thin; if too thin or improperly processed, it may develop pinholes or defects, reducing barrier performance.
Standalone aluminium foil cannot always achieve complete sealing or sufficient flexibility in all applications — hence it is usually laminated with plastic/paper to provide strength, sealability, and puncture resistance.
In complex or highly flexible packaging (requiring extensive folding or bending), aluminium foil may experience cracking or fatigue without support from other layers.
Recycling of multi-layer composite packaging (especially aluminium foil + plastic + paper) can be challenging — although aluminium foil itself is recyclable, the overall composite remains difficult to process.
Cost: Depending on thickness, alloy, and lamination structure, aluminium foil packaging is generally more expensive than simple plastic films.
Precautions for Using Flexible Packaging Aluminium Foil
- Sealing operation: Recommended heat-sealing temperature is 120–180°C, with sealing width ≥5mm, to avoid pinholes.
- Storage conditions: Keep away from light and moisture; reseal after opening.
- Prohibitions: Not suitable for microwave heating; avoid prolonged contact with strong acids or alkalis.