Heat sealing aluminum foil is a type of metal packaging material that achieves a sealing function through a heat sealing process. It is usually composed of aluminum foil combined with a heat-sealable coating, and is widely used in the food, pharmaceutical, and daily chemical industries.
Heat sealing aluminum foil perfectly combines the ultimate barrier properties of metal aluminum foil with the heat-sealable characteristics of high polymer materials. Through a simple heating and pressing process, it produces packaging materials with high strength and high sealing performance. Selecting the appropriate structure, thickness, and type of heat-sealing adhesive, and strictly controlling the production process, is key to ensuring its performance.
Heat sealing aluminum foil is a composite material made by coating one or both sides of ordinary aluminum foil with a special polymer (heat-sealing adhesive). This heat-sealing layer melts under a certain temperature, pressure, and time, then bonds to another surface (usually the same coated surface or another compatible plastic surface). After cooling, it forms a strong and airtight seal.
- Substrate: Aluminum foil – provides excellent barrier properties (light blocking, oxygen barrier, moisture resistance, aroma preservation).
- Functional layer: Heat-sealing adhesive – provides heat-sealable properties.
What is Heat Sealing?
Heat sealing involves applying heat and pressure to the edges of aluminum foil to melt and fuse the material, thereby forming a strong barrier against moisture, oxygen, and contaminants. This process is typically combined with specialized coatings or resins to enhance adhesion and sealing strength. For example, polymers such as polypropylene (PP) or polyethylene (PE) are used as heat-activated layers to improve bonding with the substrate.
Specifications of Heat Seal Aluminum Foil
| Parameter | Description |
| Common Alloys | 8011, 1235, 8079 |
| Thickness | 10 to 50 microns (µm), depending on the application and required durability |
| Heat Seal Coating | With heat-activated adhesives or polymer coatings to promote bonding during the sealing process |
| Seal Temperature | 180°C to 250°C, with temperature ranges varying based on the coating formulation and required sealing strength |
| Seal Strength | 2 to 5 pounds per inch (10 to 25 N/15mm), ensuring the integrity of the product during handling and transportation |
Heat Seal Aluminum Foil Material Selection
The material mainly uses aluminum alloys such as 8011 and 8079, with thickness usually between 70-180 microns, combining excellent barrier properties (moisture-proof, light-proof, oxidation resistance) and mechanical strength. The outer layer can be laminated with reinforcing materials such as PET, NY (nylon), while the inner layer is coated with a heat-sealing layer (such as PE, CPP, or special resins), forming a multilayer structure (e.g., PET/AL/PE, PET/NY/AL/CPP) to meet different application needs.
Functional upgrades of heat sealing aluminum foil through nano-coating technology (e.g., SiOx), plasma treatment, and other processes can further enhance barrier performance (oxygen transmission rate ≤0.3 cm³/(m²・24h・0.1MPa)), high-temperature resistance (above 121℃), and puncture resistance (graphene-enhanced products increase strength by 40%).
Heat Sealing Aluminium Foil Structure and Composition
A typical heat sealing aluminum foil structure (single-side heat sealing example) is as follows:
Protective/Outer layer: Usually the aluminum foil itself, or the other side of the aluminum foil may be printed or coated with a protective varnish.
Aluminum foil layer: Core layer, thickness usually between 7μm and 50μm, selected according to packaging requirements. For example, 20μm-25μm is commonly used for pharmaceutical blisters, while food packaging may use thicker foil.
Heat-sealing coating: Polymer coated on the inner layer of aluminum foil, commonly including:
- Polypropylene (PP)
- Polyethylene (PE)
- Ethylene-acrylic acid copolymer (EAA)
- Other special formulations of polyester, modified polyolefins, etc.
The composition of the heat-sealing adhesive determines its sealing temperature, strength, and resistance to media (acid, oil, etc.).
Heat Seal Aluminum Foil Advantages
| Advantages | Description |
| Extended Shelf Life | Heat Seal Aluminum Foil effectively seals out air, moisture, and oxidizing agents, thus prolonging the shelf life of products. This makes it an ideal choice for perishable foods and pharmaceuticals, effectively inhibiting microbial growth and maintaining product freshness and potency, ensuring consumers receive the best possible experience. |
| Tamper-Evident | Heat Seal Aluminum Foil features a significant sealing performance that clearly ruptures the seal once opened. This makes it especially suitable for applications in industries such as pharmaceuticals, where safety is a high priority, preventing tampering and ensuring product integrity and consumer safety. |
| Versatility | Heat Seal Aluminum Foil is highly adaptable and can be widely used in various packaging forms, including bags, trays, and blister packs. It is not only used extensively in the food industry but also in cosmetics, electronics, and many other sectors, providing a diverse range of packaging solutions. |
| Sustainability | Heat Seal Aluminum Foil is made of aluminum, which is 100% recyclable. With the growing trend towards eco-friendly packaging, this material has become an ideal choice. Its sustainability not only meets environmental protection needs but also helps reduce resource waste and improves the environmental footprint of the entire supply chain. |
| Heat Resistance | Heat Seal Aluminum Foil has excellent heat resistance, capable of withstanding high-temperature environments and suitable for sterilization processes at temperatures like 121°C. It is widely used in autoclave sterilization and bagged cooking applications, ensuring stable performance even under extreme conditions, protecting the contents of the package from damage. |
Chemical Compositon of Hot Sealing Aluminum Foil
| Grade | Si | Fe | Cu | Mn | Mg | Cr | Ni | Zn | Al |
| 1235 | Si+Fe: 0.65 | 0.05 | 0.05 | 0.05 | - | 0.1 | 0.06 | 99.35 | |
| 8011 | 0.5-0.9 | 0.6-1.0 | 0.1 | 0.2 | 0.05 | 0.05 | - | 0.1 | remains |
Hot sealing aluminum foil mechanical properties
| Mechanical Properties | ||||
| Alloy | Temper | Tensile strength Rm/MPa | Elongation A50mm(%)≥ | Elongation A100mm(%)≥ |
| 8011 8079 | O | 50-120 | 13-15 | 0.5-4 |
| H22 | 90-150 | 5-6 | 1.0-2.0 | |
| H24 | 120-170 | 2-5 | - | |
| H26 | 140-190 | 1-2 | - | |
| 1235 | H14 H24 | 110-160 | 4-6 | 2-3 |
| H16 H26 | 125-180 | 2 | 1 | |
Working Principle of Heat Sealing Aluminium Foil
- Induction sealing: This non-contact method uses an electromagnetic field to heat the aluminum foil layer placed under the bottle cap (usually aluminum). The heat melts the polymer layer on the foil, which then bonds to the container edge, forming an airtight seal.
- Direct heat sealing: In this method, a heat sealer directly applies heat to the aluminum foil and substrate (such as plastic or metal surface). The heat melts the heat-sealing layer of the foil and bonds it to the substrate.
The choice of method depends on the application, the materials involved, and the required sealing characteristics.
Popular Sizes of Haomei Heat Seal Aluminum Foil
- Silver heat seal foil - 115 mm rolls
- Transparent Seal Perforation - 115 mm Roll
- Heat Seal Foil - 78 mm rolls
- Red heat seal foil - 115 mm rolls
- Pierce Seal Foil - 115 mm Roll
- Peel Seal Aluminium Foil - 78 mm Roll
- 38 µm Pierceable and Peelable Aluminium (Blue) Heat Seal Foil
- Pierce Seal Foil - 78 mm Roll
- 70 µm Peelable AVE Aluminium (Red) Heat Seal Foil
- Transparent Seal Peel - 78mm Sterile Roll
- 25 µm Easy Pierce (Green) Heat Seal Foil
- Transparent Seal Peel - 78 mm Roll
- 85 µm Aluminium (Black) Heat Seal Foil
- Heat Seal Foil - 115 mm Roll
- Gold heat seal foil - 115 mm rolls
- Silver heat seal foil - 78 mm rolls
- Transparent Seal Perforation - 78 mm Roll
- Peel Seal Aluminium Foil - 115 mm Roll
- Transparent Seal Peel - 115 mm Roll
- Green heat seal foil - 78 mm rolls
- Red heat seal foil - 78 mm rolls
- Transparent Seal Perforation - 115 mm Roll
- Transparent Seal Perforation - 78 mm Roll
- 20 µm Easy Pierce (Green) Heat Seal Foil
- Green heat seal foil - 115 mm rolls
- Gold heat seal foil - 78 mm rolls
Applications of Hot Sealing Aluminum Foil
Food Packaging
- Chocolate, candy: twist wrapping or flat folding packaging.
- Dairy products: butter, cheese slice packaging.
- Beverages: bottle mouth sealing films (e.g., yogurt lids).
- Convenience foods: sauce packets, powder packets.
- Steaming/boiling bags: used for high-temperature sterilized foods.
Pharmaceutical Packaging
The most common application is pharmaceutical blister packaging, sealing tablets or capsules between aluminum foil and plastic sheets (such as PVC, PVDC).
- Granules, powder bags: for packaging Chinese medicine granules, antibiotic powders, etc.
- Lid material: used for sealing bottles, tubes, and cups.
New Energy Field
In the new energy and electronics field, heat sealing aluminum foil is a key base material for manufacturing soft-pack battery core packaging materials and electromagnetic shielding components for electronic devices.
- Soft-pack materials for lithium batteries
- Aluminum-plastic films for lithium batteries
- 5G device electromagnetic shielding materials
Daily Chemical and Industrial Products
Products such as cosmetics and household goods often use heat sealing aluminum foil for packaging to protect contents and present a high-end appearance.
- Cosmetic mask bags, skincare samples.
- Chemical products, precision parts moisture-proof packaging.
| Application Area | Description |
| Food Packaging | Heat Seal Aluminum Foil is widely used in food packaging, especially for sealing yogurt cups, milk cartons, cheese packaging, and snack bags. Its excellent sealing performance effectively isolates air and moisture, maintaining product freshness and extending shelf life, preventing oxidation and microbial contamination, thus ensuring consumers enjoy fresh and safe food. |
| Pharmaceutical Packaging | Heat Seal Aluminum Foil plays a crucial role in pharmaceutical packaging. It ensures the integrity of the medication during transportation and storage through blister packs and unit-dose packaging. The material provides strict sterile protection, preventing external contaminants and moisture from entering, thus ensuring the potency and safety of the drugs. |
| Cosmetic Packaging | Heat Seal Aluminum Foil is widely used in cosmetic packaging, particularly for sealing containers of creams, serums, and other cosmetic products. Its effective sealing performance prevents pollutants in the air from entering, maintaining the purity and effectiveness of the cosmetics, while also extending their shelf life, ensuring safety and performance when used by consumers. |
| Industrial Applications | Heat Seal Aluminum Foil is also used in various industrial packaging applications, particularly for packaging chemicals, powders, and other sensitive materials that require secure and stable sealing. Due to its chemical resistance and stability, Heat Seal Aluminum Foil effectively prevents external factors from affecting sensitive substances, ensuring the safety and integrity of products during transportation and storage. |
Heat seal aluminum foil is a key material in modern packaging, providing protection, versatility, and branding opportunities across various industries.
8011 Hot Sealing Aluminum Foil for Yogurt Cup Lids >
For yogurt cup lids, the hot sealing aluminum foil used needs to have good flexibility and plasticity to ensure a reliable seal on the cup's opening. Typically, the 8011 aluminum foil used has a thickness ranging from 0.01 to 0.05 millimeters, with a smooth surface free from scratches, wrinkles, or other defects. This type of foil requires excellent sealing properties, good antibacterial performance, and outstanding puncture resistance to prevent leaks or contamination during use.
1235 Hot Sealing Aluminum Foil for Pharmaceutical Packaging
For pharmaceutical packaging, the 1235 hot sealing aluminum foil must meet pharmaceutical-grade sterility requirements and have a clean and flat surface. Generally, high-purity aluminum materials from the 1000 series, such as the 1235 alloy, are used, with foil thicknesses ranging from 0.015 to 0.2 millimeters. This foil offers good puncture and peel performance, ensuring easy handling and providing effective sealing.
Medical Grade Heat Seal Foil Tape
Medical-grade heat seal aluminum foil tape is an efficient, cost-effective, and reliable sealing solution, widely used to seal microporous plates, holes, and channels in diagnostic equipment. This tape can be used over a wide temperature range, exhibiting peelable, puncture-resistant, and solvent-resistant properties, and can adhere firmly to various substrates to ensure sealing performance.
8011 Hot Sealing Aluminum Foil Bags for Food Packaging
8011 aluminum foil used for food packaging in hot sealing aluminum foil bags is typically laminated with plastic films (such as PE, PET, etc.), with foil thicknesses generally ranging from 0.04 to 0.09 millimeters. These foil bags have excellent air and liquid barrier properties, effectively blocking oxygen and moisture, making them suitable for refrigeration and freezing environments from -30°C to 100°C. The heat-sealed edges of the bags are secure and aesthetically pleasing, free from burrs, ensuring complete isolation from the external environment and preserving the freshness and quality of the food.
Key Parameters of Aluminum Foil Heat Sealing Process
To achieve ideal heat sealing, three core parameters need to be controlled:
- Temperature: Must reach the melting point of the heat-sealing adhesive but should not be too high, or it may cause degradation, burning through, or sticking to the sealing plate.
- Pressure: Provides enough pressure to ensure full contact and fusion of the two molten surfaces.
- Time: Maintain the temperature and pressure for sufficient time to ensure heat transfer and complete fusion.
These three need to be optimized according to the specific heat sealing aluminum foil material and equipment.
Common Problems and Solutions of Heat Sealing Aluminium Foil
| Problem | Cause Analysis | Solution |
| Seal not firm | Temperature too low, insufficient pressure, poor-quality aluminum foil | Increase temperature to melting point ±5℃, increase pressure to 0.3MPa, replace with qualified aluminum foil |
| Seal brittle or burnt through | Time too long or temperature too high | Reduce time to within 1 second, lower temperature by 10-20℃ |
| Heat-sealing layer peeling off | Adhesive not fully cured, poor heat resistance of ink | Extend curing time (more than 72 hours), switch to two-component ink |
| Aluminum foil tearing | Excessive tension or material brittleness | Adjust unwinding tension to 5-10N, choose more ductile 8011 alloy |
| Wrinkles after sealing | Improper tension control or uneven sealing plate | Check aluminum foil quality and sealing environment flatness |
| Aluminum foil delamination (pinholes) | Aluminum foil itself has pinholes, excessive pressure during sealing causes puncture, contents have sharp edges | Inspect aluminum foil quality |