Few packaging technologies are as universal and diverse as barrier films.
These materials can be found in a huge range of applications, and are engineered to meet the needs of industries of all kinds. If you’ve cracked open a bag of snacks recently, you’ve seen first-hand what barrier films can do to preserve quality and help keep your food fresh.
While the average consumer might not think twice about how barrier films are used and what makes them unique, companies in the food industry and other competitive markets rely heavily on these types of materials.
Let’s explore what barrier films are, how they’re used, and the different types of materials we see used throughout industries including food, medicine, and mechanical components.
What Is a Barrier Film?
Since its applications are so wide-reaching, a barrier film is mainly defined by its material and its thickness. Films generally range between .06 mm and .25 mm, while anything thicker than that is categorized as a sheet.
Barrier films also tend to be made from plastic, although modern variations may include metallized materials that change colors. Because the layers are so thin, they can be customized and fitted with extreme precision, allowing manufacturers to create proprietary solutions for individual products.
Flexibility paired with strength and stability help form superior films that make all the difference in production.
This results in a product that not only looks and feels high-quality, but also has visual appeal (in-store or online), protects against elements like moisture and gas, and provides a workable canvas for branding, labeling, and differentiation.
All these factors combine to make barrier films a vital component in modern packaging and production, especially with perishable food products and other consumables.
What Are OTR and MVTR?
When comparing barrier films for food packaging, oxygen transmission rate (OTR) and moisture vapor transmission rates (MVTR) are the two main metrics to note.
OTR measures how much oxygen gas passes through a barrier film over a certain period of time, while MVTR measures how much water vapor passes through. These are relevant metrics for a wide array of applications from industrial and construction settings to the manufacturing of snack foods, household items, and other consumables and devices.
Both measurements are worth tracking due to the interaction of oxygen and moisture with various products, particularly over long periods of time. Two days of shipping or time spent in storage may not impact a product’s appearance or quality, but what about two weeks, two months, and beyond? These extended durations are when barrier films matter most.
To maintain peak product quality, manufacturers must source barrier films that not only maximize OTR and MVTR in the short term but also limit permeability over time (even under high temperatures and humidity) and ensure a good user experience once the product is in use.
What Are the Different Levels of Barrier Films?
With limitless variations of barrier films available, it helps to categorize these products into levels based on strength and performance. Here are the basic levels of barrier films, typical materials, and the properties they’re known for in common applications.
Basic: Single Layer
Not much protection can be expected from a single-layer barrier film, but these materials can get the job done in many short-term food service applications, such as self-adhesive “cling film” made from soft polyvinyl chloride (PVC).
Polyethylene film (also known as shrink wrap), polyamide (nylon), and other single-layer films are quick and accessible at home. These products tend to fall short with large-scale transport, shipping, and storage.
At most, you may see an interior single-layer film used for individually-wrapped products in cardboard containers or tins, but they don’t serve as a primary protective layer.
Basic: Double Layer
With PVC or polyethylene as a common base, another film can be thermoformed on top of that initial layer to create a more stable material with superior properties.
This is how producers achieve a better balance of impermeability to both moisture, oxygen, and even temperatures — which can’t be accomplished by a single layer film alone.
For example, oxygen-proof polyamide combined with water-vapor-proof polyethylene will create an ideal double-layer film that can better protect food products and withstand harsher conditions for longer durations.
The advantage here is that double-layer films are still lightweight and highly flexible, morphing to the dimensions of a product and permitting transparency. However, these films can’t be classified as high-performing, and aren’t recommended for large-scale transport and storage.
Examples of moderate barrier films may include polyethylene terephthalate (PET), oriented polypropylene (OPP), or biaxially-oriented polypropylene (BOPP). These films offer strong barrier properties, including better moisture and oxygen protection, along with better labeling capabilities.
These films also have a better look and feel that can compete for consumer attention on store shelves. What’s more, they can deliver a good user experience after purchase.
Customization options are greater, packaging prices are reasonable, and orders can be executed at scale, making these good intermediate options for food products, and other consumables.
At the top of the range for barrier films are high-performing materials made from multiple layers and including modern industrial additives and treatments.
The result is a highly customized end product, engineered with precision in the exact specifications of the producer.
What Are Examples of High-Barrier Films?
Popular high-barrier films are now more accessible, customizable, and affordable for producers in the food industry and beyond. Here are some of the best-performing barrier films available now and what properties they offer.
Ethylene-Vinyl Alcohol (EVOH)
A leader in oxygen barrier properties, EVOH is used to keep food and beverage items fresh, as well as medical products and cosmetics. EVOH works best in a layered configuration between an HDPE outer wall and an adhesive resin such as polyamide on either side.
This setup is found in many plastic bottles and jars, maximizing protection against a full range of gases and humidity while regulating temperatures.
Metallized Polyester (Mylar, VMPET, BOPET, & METPET)
A modern upgrade to aluminum foil, metallized polyester materials give you the best of both worlds in terms of thin thermoplastic films and superior barrier properties..
This combination is achieved by coating a polymer film with a thin layer of metal, giving the material a glossy metallic finish while enhancing oxygen and moisture barrier properties and retaining lightweight flexibility.
Mylar is a popular version of this high-performing film, used in electronics circuits, snack and coffee packages, decorations, and insulation.
Nylon film (a thin form of polyamide) is tough. It’s resistant to scratches, punctures, and flex-cracks, all of which can negatively impact the look and feel of products on the shelf.
Producers also have access to a wide variety of nylon film types, based on what they need in terms of barrier properties and visual attributes.
PVDC (Polyvinylidene Chloride)
PVDC excels in protecting products from vapor, moisture, and oxygen, and is often combined with other layers for increased effect.
On its own, PVDC is still a high-performance barrier film with great tensile strength, ideal for delicate and perishable products with see-through packaging.
Why Are Food Barrier Films Popular?
Food producers aim to bring products to market with speed, stability, longevity, and a degree of visual appeal to catch consumers’ attention and encourage a purchase.
Only the best barrier films allow for all these factors to be balanced simultaneously, which explains why companies seek high-performing materials from trusted partners.
The right barrier film selection could lead to record-setting sales and customer satisfaction, making it a critical part of the production decision chain.
The Bottom Line
There’s a specialized film for any application you can imagine, from shipping televisions to developing the best package for snacks or medicine. At Dymapak, these films can be customized to your exact specifications, boosting product quality to help keep your customers happy.
Choose the right barrier films and utilize the perfect package for products that arrive safe and sound.