What Is Metallized PET Film?
metallized pet film is a thin, flexible film made from biaxially oriented polyethylene terephthalate (BOPET) that has been coated with a microscopic layer of aluminum through a vacuum deposition process. The result is a lightweight material that combines the reflective properties and barrier performance of metal with the durability and flexibility of plastic. It is commonly used in food packaging, labels, insulation materials, electronics, and decorative applications where both aesthetic and functional qualities are required.
1) How Metallized pet film Is Produced
The production process of metallized pet film involves vacuum metallization, a precise coating method that applies an ultra-thin metal layer to the surface of a clear PET base film.
Process Steps:
The PET film is first cleaned and treated (corona or plasma treatment) to enhance surface energy and metal adhesion.
The film is then fed into a vacuum chamber, where aluminum wire is heated and evaporated into vapor.
The aluminum vapor condenses onto the moving PET film, forming a uniform metallic layer that is only 20–80 nanometers thick.
The metallized film is rewound, inspected, and slit into the desired widths for lamination or printing applications.
Typical construction in laminates:
Ink/Print | Adhesive | Metallized PET (OD 1.8–2.6) | Adhesive | Sealant (PE/CPP/BOPE/CPA)
Metallized side is usually placed inside the laminate to protect the fragile metal layer from oxidation and mechanical abrasion.
For heat sealing, metallized PET is laminated to a sealant web such as LDPE, CPP, BOPE, or CPA to provide sealing and product compatibility.
Key specs you’ll see on a datasheet:
Thickness (PET): 8–30 µm (most common 12 µm)
Optical Density (OD): 1.6–2.8 (higher OD = thicker metal = stronger barrier)
Barrier Performance: OTR < 1.0 cc/m²·day; WVTR < 1.0 g/m²·day at 23°C, 50% RH
Surface Energy: ≥ 42 dynes (treated side for adhesive or ink bonding)
Temperature Resistance: up to 120°C continuous use, softening around 150°C
2) Properties and Advantages
A) Excellent Barrier Protection
Metallized PET film acts as an effective barrier against moisture, oxygen, light, and aroma loss. The aluminum layer significantly reduces gas permeability and extends the shelf life of products like snacks, coffee, and powdered foods. It provides near-foil-level barrier performance at a fraction of the cost and weight.
B) Lightweight Yet Strong
The BOPET base offers exceptional mechanical strength, puncture resistance, and dimensional stability, allowing the film to run smoothly on high-speed packaging lines without stretching or tearing. It can withstand both cold and hot filling conditions.
C) Enhanced Visual Appeal
The metallized surface provides a shiny, reflective appearance that creates a premium look for product packaging, labels, and decorative laminations. Reverse printing on the non-metal side adds depth and protection to graphics.
D) Thermal and Chemical Stability
PET offers superior heat resistance and solvent compatibility compared to other base films such as BOPP. This makes metallized PET suitable for demanding laminations, vacuum pouches, and heat-resistant packaging.
E) Cost-Effective and Sustainable
Since the aluminum layer is extremely thin, metallized PET achieves excellent barrier performance while remaining lightweight and cost-efficient. It uses far less metal than foil and can sometimes be processed in recyclable mono-material structures when combined with compatible layers.
3) Applications of Metallized PET Film
1. Flexible Packaging
Used as the barrier layer in pouches, sachets, and snack packaging (e.g., VMPET/PE, VMPET/CPP).
Extends product shelf life by preventing moisture and oxygen ingress.
Common in coffee, tea, spices, nuts, pet food, and powdered milk.
2. Labels and Graphic Films
Metallized PET creates mirror-like effects in labels, tags, and wrapping materials.
Reverse printing protects artwork and maintains high gloss for premium branding.
3. Insulation and Building Materials
Used as a reflective insulation film in buildings, HVAC ducts, and reflective barriers.
The aluminum coating reflects radiant heat and reduces energy loss.
4. Electrical and Industrial Applications
Metallized PET acts as a dielectric film in capacitors and as a shielding layer in electronics to protect against electromagnetic interference (EMI).
Also used for anti-static bags and release liners.
5. Decorative Uses
Common in gift wrapping, ribbons, balloons, and craft materials due to its glossy metallic finish and easy handling.
4) Important Considerations When Using Metallized PET Film
A) Lamination and Adhesive Selection
Choose a compatible adhesive system—typically polyurethane-based (solvent or solventless). Incorrect adhesive type or coat-weight can cause metal pick-off or delamination. The metallized layer should be laminated on the inside to maintain reflectivity and protection.
B) Printing and Surface Treatment
Metallized PET usually requires corona treatment (≥ 40 dynes) for proper ink adhesion. The printable side should always be tested for wetting and smoothness before full-scale production.
C) Flex Crack Resistance
Although PET is strong, the metal layer can develop micro-cracks if repeatedly folded or flexed, which may reduce barrier efficiency. To avoid this, use films with moderate OD or add protective coatings.
D) Retort and Heat Processing
Standard metallized PET films are not suitable for high-temperature sterilization (121°C) unless specially formulated. For retort pouches, use reinforced or aluminum-foil alternatives.
E) Storage and Handling
Store rolls in a dry, dust-free environment (18–25°C, <60% RH) to prevent oxidation and maintain surface quality. Always use clean cores and edge protectors to avoid surface damage.
5) Sustainability and Recycling Outlook
While metallized PET film is not as recyclable as clear PET due to the presence of the metal layer, it still represents a more material-efficient solution than foil laminates. Only a fraction of a gram of aluminum is used per square meter.
Emerging recycling technologies—such as plasma delamination or chemical recovery—are improving the recyclability of metallized films. Additionally, mono-material packaging structures using metallized BOPE or BOPP are gaining popularity in flexible packaging sustainability programs.
Summary
Metallized PET film combines the strength of polyester with the reflective and barrier properties of aluminum. It is lightweight, durable, visually attractive, and provides strong resistance against moisture, oxygen, and light. This makes it ideal for flexible packaging, labels, insulation, and industrial applications.
By balancing appearance, performance, and cost, metallized PET continues to be one of the most versatile barrier films in global packaging. It offers a foil-like finish, high mechanical stability, and excellent processability—a combination that makes it indispensable in modern converting and lamination industries.