Flexible packaging uses metallized PET film that has a wide range of applications in the packaging industry. But before flexible packaging came to life, Aluminum foil is being widely used in the past until present. Because of its exceptional barrier properties that can be applied to wet and dry foods.
Due to constant innovation in the packaging sector to continuously improved the recyclability of aluminum foil and to lower the cost. Metallized PET film was introduced providing some characteristics that aluminum foil has but with its enhanced properties to best suit your products. But how does these two differ from one another in the packaging sector and what is the right material to use that suits your products best.
In choosing between the two we have to keep in mind that they each posses and contain different features and purposes.
Aluminum foil extends your products shelf life while providing exceptional barrier properties. For the metallized PET film it offers a more economical solution that provides puncture resistance, gas- barrier durability and aesthetic appearance for your products.
Aluminum foil is broadly used because of barrier properties and are typically applied to powdered, dried foods, confectionary, and dairy items. Due to the constant development of the economy and the environment. We constantly try to look for a better alternative in the packaging industry. flexible packaging was introduced for a better and economical solution than plastic packaging.
Not only does it uses recyclable raw materials but it also provide barrier characteristics for your products in the long run. This uses complex films namely metallized PET film that helps reduce cost. Also offering some characteristics that the aluminum foil has. To get to know aluminum foil and metallized PET film in flexible packaging then keep on reading.
The definitions
1.1 What is aluminum foil in flexible packaging?
Aluminum foil are your all around type of packaging that can be found in various sectors of the industry. It serves as a barrier layer in flexible packaging where its production begins with a sequence of cold roll steps. Each process of the aluminum foil reduces half of the thickness of the aluminum ingot making it lightweight and durable. In the final stage, the foil is doubled over and sprayed with oil for release. Then the foils are rolled, separated, rerolled, and slit into the desired width and length.
Aluminum foil can be folded in many ways to suit your packaging needs. Making it ideally compatible for recycling, packing and wrapping different kinds of products.
1.2 What is metallized PET film in flexible packaging?
On the other hand metalized PET film is made entirely of light metals ( aluminum). Metallized PET films are plastic foils that are evaporated with aluminum powder in a high vacuum. This makes the film less gas-tight than aluminum foil. But they are more tear-resistant, flexible, and light which gives a more polished finish. The process for creating metallized PET films uses pure aluminum powder infused with 98% aluminum content.
Its end result makes the film have a metallic shine to create an optical effect. While viewing the inside of the packaging at the same time. Also, metalized PET films are less sensitive to corrosion and are not as wrinkle-prone compared to aluminum films. In line with that, it also offers a more cost-effective solution to manufacturers and is an environmentally alternative packaging.
Properties of aluminum foil and metalized PET film
| Features | Aluminum Foil | Metallized Pet Film |
| Barrier | Barrier effect against light,oxygen, moisture, and bacteria. (has the best barrier effect among packaging) | provide excellent barrier to moisture and oxygen. |
| OTR | Aluminum foil in flexible packaging provides complete barrier against oxygen ( and moisture). | 15-31% lower than of aluminum foil in terms of oxygen transmission rate. |
| WVTR | <0.01 gm/mยฒ/24hr for the laminate itself and less than <0.05gm/mยฒ/24hrs for converted laminate | 55-74% lower than of aluminum foil. |
| UV light | Aluminum (Al) is the only material that has a high reflectivity for ultraviolet rays in the wavelength range of 250 nm to 400 nm. | Blocks light and prevents UV rays from penetrating resulting to longer shelf life for your products. |
| Thickness | 7 microns | 12 microns |
| Dead fold characteristics | The ductility of aluminum foil makes it foldable into a variety of container shapes. Also aluminum foil retains the shape once it is folded. | Does not retain the shape when folded but has excellent elasticity and guarantees absolute diffusion density with a glossy smooth finished. |
To sum it up, aluminum foil provides barrier function that repels moisture,oxygen, aroma and against the impact of light. Due to its oxygen barrier, it prevents chemicals in the food from reactions that can cause odors and rancidity. It is known to be one of the most expensive layer in a multilayer flexible packaging because of its barrier characteristics.
Metallized PET film is ideal for applications that requires preservation of flavors and freshness. This is suitable for packaging application in the technical and industrial sectors. Keep on reading to find out more about the differences of aluminum film and metallized pet film in flexible packaging.
How to physically distinguish aluminium foil and metallized PET film in flexible packaging?
There are various methods used to physically distinguish them. For example, try shining a light in aluminum foil and metalized PET film to see which will pass through. If the light passes through the film then obviously it is metalized PET film. Because it does not possess an opaque barrier that can prevent light from passing through. Unlike the aluminum foil made up of metallic sheets light cannot pass through rather it can only reflect it.
Also in terms of appearance aluminum foil looks harder and has a matte finish compared to metalized PET. For metalized PET it has a softer look and glossy coating. When holding aluminum foil it is much lighter and pliable than metalized PET film.
The laminated fastness with printing film
Inflexible packaging, we use the multilayer material laminated with aluminum foil or metalized PET film. By doing so we have to consider the laminated fastness of these films. Laminated aluminum foil film has great seal abilities, good chemical and water resistance. Providing good benefits such as good oxygen barrier and fine forming properties. That maintains the freshness of your products for a longer period.
The metalized PET film it has a thin aluminum powder coated on the surface. Because of this, we cannot laminate the metalized PET like what we do on our Bopp, PET, or nylon film. Why? because of the thin aluminum layer on the metalized pet. This will produce a chemical transfer between the layers compromising the fastness and stability of the bag.
How to choose between aluminum foil and Metallized PET film in your packaging?
If you are a CPG brand or does not need high requirement for the shelf life, storage packaging,, or in need of a special environment. Then MET PET is for you it can be an ideal foil- replacement and cost-effective solution for your packaging. Products like coffee, nuts, dried foods, and powdered energy drink works best with Metallized PET film.
Since metallized pet film is lightweight it allows more packaging units per square meters. Also with the continuous advancement of packaging technologies metalized PET film continuous to increase in demand.
On the other hand if your packaging requires special barrier properties or shielding ability to protect and prolong your products shelf life then aluminum foil is your best bet. The efficient storage that aluminum packaging has for food and beverages reduces the need for a cooling effect and makes it spoil slower.
Another good thing is the low weight of the aluminum reduces the required energy it needs during transport. Aluminum foil is best suited for products like instant beverages, snacks, sausage, dried meat, baby food, ready meals and preserves. But due to the high cost the demand for thinner aluminum foils is increasing. Another thing to remember is that aluminum reacts with acidic or salty foods, the aluminum ions dissolve and can be passed into foods.
Sustainable
Aluminum foil alone is a metal material made up of thin aluminum sheets. While Metallized PET is a plastic component with a single layer or thin sheet of aluminum. As i have said before the production of aluminum foil requires more energy, water, and greenhouse gas emissions compared to plastic films. But despite that aluminum foil can be recycled. Flexible packaging that uses aluminum foil has a high product to pack ratio than rigid packaging.
In addition to that aluminum material is fully recyclable resulting to increased collection and recycling ratio for aluminum foil. This means that less primary aluminum will be needed. The significant energy saving for processed recycled aluminum requires 95% less energy than that of the primary metal.
The metallized PET is based on polyester resin, so it can be recycled into other plastic products, reducing landfill waste. An environmentally friendly solution fo r recycling Metallized Pet is developed. This means Met PET is recycled into PET pellets with enhanced physical, mechanical, optical, and aesthetic properties. The physical, mechanical, and aesthetic properties of the straps, yarn produced from recycled Met Pet can be compared to virgin Pet pellets.
Conclusion
To sum it up laminated metallized films create an enhanced layer of barrier protection ofor your products. In food packaging aluminum foil is typically laminated with plastic films. Using aluminum foil has its benefits like its light weight, resistance to water, reflection to heat and UV light as well as recyclability.
On the other hand Metallized PET is also popular for food manufacturers. Because of its ability to preserve the freshness and flavor or the product. Furthermore, both these films offers scratch resistance properties protecting the products from packaging lines and environmental factors while in transit. Giving a high quality and aesthetic finish for your product packaging.
