Aluminum foil has been used for over 100 years, especially in the packaging industry. But at the same time, a serious competitor has entered the arena. The expanding range of metalized PET films
has made it one of the fastest growing segments in the flexible packaging market.
At first glance, the two types of films are similar. However, they offer very different properties, depending on the application.
Characteristics of aluminum foil
Aluminum foil is usually made of pure aluminum with at least 99% aluminum content. In a series of passes through the rolling mill, the aluminum reaches the desired thickness.
The very thin foils are double rolled together in the final step and then separated again. This process produces two natural finishes: the outer side of the foil touching the mill work rolls for a "bright" finish, and the foil on the other side for a "matte" finish.
Aluminum solidifies by cold rolling, becoming hard and brittle. However, the subsequent heat treatment in the annealing furnace made the film soft and flexible again.
Aluminum foil with a thickness of about 12-20 µ has barrier properties. This means that these foils are impermeable to water and air. Thinner foils do not guarantee the same 100% barrier properties. However, they also have barrier properties and ensure that food stays fresh longer due to their photoprotective effect.
Aluminum foil is physiologically harmless to food. However, acidic, alkaline, and salty foods should not come into contact with the film. Aluminum foil is lightweight and resistant to water, water vapor, grease, and gas, it reflects light, heat, and UV rays and is not charged. Plus, it's fire-resistant and easy to recycle.
For packaging, pure aluminum foil is rarely used. In most cases, aluminum foil is laminated with plastic film (such as PET, PE, or PP) or paper. Let's talk about the aluminum composite film. Composite films have some advantages over pure aluminum foils, for example, higher rust resistance and/or stiffness. In addition, aluminum foil can also be painted and printed to meet the requirements of modern packaging.
Aluminum strips can be deep drawn into containers or trays and cans. Then it maintains the drawn shape. Aluminum can be bent and folded without losing its barrier properties.
Characteristics of PET-met film
In contrast to aluminum foils, which are made entirely of light metal, metalized PET foils are plastic foils that are only evaporated with aluminum powder in a high vacuum. In this process, powdered pure aluminum with an aluminum content of at least 99.98% is used. The films produced in this way have a metallic luster, which allows special optical effects to be obtained.
In addition to the optical effect, the vaporization of aluminum, in particular, helps to improve its barrier effect against vapors, gases, and odors compared to non-metalized plastic films. Overall, metalized PET films are less airtight than "true" aluminum foils, but are more tear-resistant, more flexible, and lighter. Also, they are less sensitive to corrosion and do not wrinkle as easily as pure aluminum foil.
The PET-met film is made from only 1% of the aluminum required for aluminum foil. Therefore, PET-met is of particular interest as a cost-effective and more environmentally friendly alternative to aluminum.
Applications of aluminum foil
Aluminum foil is a true all-rounder and can be found in almost all industries. Lightweight and tear-resistant, aluminum foil can be folded in a variety of ways, making it ideal for wrapping and wrapping different types of products and product shapes.
Pharmaceutical industry: Aluminium foil is used to protect pharmaceuticals from external influences during transportation and storage.
Food industry: Aluminum foil has good hygienic properties and light and gas barrier properties.
Construction industry: The insulating effect of aluminum foil is used, for example, to insulate sewers, pipes, and complete buildings, and to build a moisture barrier for the walls of saunas or wine cellars.
Energy field: Aluminum foil is light in weight and high in electrical conductivity, and can be used for insulation of power cables. On the other hand, the telecommunications industry uses aluminum foil and its special barrier properties to protect fiber optic cables from moisture and shield communication cables from electrostatic interference caused by electronic equipment.
Applications of metalized PET film
Metallized PET film is the ideal solution for all applications where flavor and freshness need to be maintained. It is suitable for many applications in the packaging industry as well as in the technical and industrial fields.
PET films have particular advantages where the higher airtightness of aluminum foils is not required.
Metallized PET films can be printed like aluminum foil and are available in a variety of optical variants. The gloss of metalized PET film is much higher than that of aluminum foil, so metalized PET film can achieve a stronger mirror effect. This is also used when printing - for example, without a white primer, the yellow will shimmer with gold.
As such, PET film offers an ideal opportunity to combine certain protection and barrier functions with an aesthetically pleasing appearance - even if the food protection is not as high as true aluminum foil and may require a shorter shelf life.
Used in combination with other materials, such as PET foil, it is ideal for snack packaging, thermoformable container lids such as yogurt cups, or cosmetic refill bags. Coffee and pet kibble stay dry in these PET packages and retain their full aroma and flavor for a long time.
In the special case of acidic, alkaline, or salty foods, metalized PET films are the perfect alternative to aluminum foils, as prolonged or large contact areas of aluminum with these materials can release potentially harmful aluminum emissions into edible the content.
Insulation systems, for example, to prevent heat radiation in buildings or heat conduction in vacuum insulated panels, can also be implemented using metalized PET films. In addition, PET metal films can be used for decorative tapes. Labels made from metalized PET film are highly heat and chemical resistant to ensure long-term durability.
The above describes the applications and differences between aluminum foil and metalized PET film in detail, if you still have questions or want to buy them, welcome to contact us
Polarfoil is a professional custom thermal insulation materials manufacturer
. We have 3 vacuum coating machines, and 8 PE extrusion coating production lines, guided by the 6S management system. The "pole foil" is made by vacuum coating. Low-density polyethylene-coated polyester film or low-density polyethylene-coated pure aluminum foil is one of its famous hot-selling products.