Understanding EVOH plastic food packaging

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Understanding EVOH plastic food packaging

Ethylene-vinyl alcohol (EVOH) is now becoming one of the top well-known flexible thermoplastic oxygen barrier polymers in use today. Food stored in refrigerators needs it. In stiff or semi-rigid food containers, thermoplastic barrier materials are often made of EVOH.

The packaging required to keep up with demand and expectations as the food sector evolved. Longer shelf life was becoming more necessary as food items became more technological and competitive. Therefore, safety and aesthetics for packaging made from EVOH become more crucial than ever.

In this article, let’s learn about EVOH plastic food packaging and its applications in the food packaging sector.

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1. What is EVOH plastic food packaging?

1.1. Definition

What is EVOH plastic food packaging? Definition

EVOH, also known as ethylene vinyl alcohol copolymer, is a thermoplastic material widely used in the food packaging industry due to its exceptional barrier properties. The prosperity of preventing the permeation of gasses, liquids, and aromas helps EVOH become the top choice for food packaging applications. 

The EVOH packaging material is produced by the copolymerization of ethylene and vinyl alcohol monomers. During the polymerization process, the vinyl alcohol units are partially hydrolyzed, creating a network of hydrogen bonds within the polymer chain. These hydrogen bonds give EVOH its high barrier properties, as they prevent the diffusion of gasses and liquids.

Because of its high oxygen barrier properties, EVOH is applied to manufacturepackaging perishable food products such as dairy products, and prepared foods. This feature helps to prevent spoilage and extends the shelf life of food products. Additionally, EVOH provides good barrier protection against other gasses such as carbon dioxide, nitrogen, and volatile organic compounds (VOCs), which helps to preserve the freshness and quality of food products. EVOH is commonly used in multi-layer packaging structures, where it is typically used as a barrier layer between two layers of polyethylene (PE) or polypropylene (PP). These multi-layer structures offer the desired combination of strength, barrier, and flexibility, and provide an effective barrier to moisture, oxygen, and other gasses.

It's important to note that EVOH is not biodegradable, and like other plastic materials, it can have an impact on the environment if not properly disposed of. As a result, we should recycle EVOH plastic food packaging whenever possible and properly dispose of it in accordance with local regulations.

1.2. Benefits of EVOH plastic food packaging

Eliminating unnecessary product and packaging waste is the most effective method for lowering impact on the environment. By reducing waste, maximizing efficiency, and preserving available resources, EVOH plastic food packaging helps businesses save budgets. Here is a deeper insightinto the environmental benefits of EVOH plastic food packaging:

Less packaging, more functions

When EVOH is employed in the packaging process, the layers of products, which are just a few micrometers thick, enable the use of fewer resources while yet providing an important barrier function. The ability to effectively store, transport, and show the product is aided by portions that are the optimal size while still being lightweight. The preservation of freshness and quality over longer periods of time helps cut down on waste and conserves resources.

Resist organic solvents and oils

EVOH is not affected by oils or organic solvents in any way. They are an excellent choice for the packaging of oily products, including edible oils, and mineral oils. Additionally, it is used in the production of industrial chemicals and organic solvents.

Weather resistance

EVOH plastic food packaging is very resistant to the effects of the elements. The color of the polymer does not change, even when it is subjected to sunlight; neither does it become opaque nor does it become yellow. Changes in the mechanical qualities are negligible, which indicates good resilience to the overall impacts of the weather.

1.3. Why use EVOH in food packaging?

Why use EVOH in food packaging?

EVOH plastic is widely used in the food packaging industry due to its exceptional barrier properties. But that’s not the end. There are more explanations on why EVOH is used for food packaging:

High barrier property

As mentioned above, EVOH plastic food packaging creates an effective oxygen barrier that guards against oxidation and preserves important food components. So it guarantees the freshness, extended periods of storage and eliminates the need for additional preservatives. 

Outstanding transparency and gloss

EVOH has a great level of transparency in addition to offering an effective barrier against oxygen. EVOH produces very clear images because of its high gloss and minimal haze. The application of EVOH to a package's outside surface produces a brilliant glow that enhances the package's look.

Antistatic properties

EVOH is a polymer that has excellent antistatic properties. When applied as a surface layer, it prevents dust from sticking to the box and keeps it clean. Utilizing it is a smart decision, particularly if you work in the food sector.

Thickness

The depth of the EVOH layer is another element that affects barrier performance. In multilayer constructions, EVOH is often utilized as a thin barrier layer. The application will determine the thickness. As a barrier for food packing, an EVOH layer of a few micrometers, often less than 10 m, is sufficient.

The thickness distribution of the material is significantly impacted by thermoforming. Heat is used to soften the film substance. In this procedure, it is shaped by mechanical stretching and pressure. The depth and angle of the corner drawings affect the final packaging's thickness distribution and surface area.

However, this impact is somewhat reversible. Because stretching the film has the potential to change how the polymer chains are oriented. It might lead to tighter proximity. Chain movement may therefore be constrained in amorphous zones. The oxygen molecules find it more challenging to cross through. Lower oxygen permeability is the outcome.

Cost-effectiveness

EVOH packaging lowers the cost of manufacture. Your bottom line may be impacted by a decrease in manufacturing costs. Better raw material usage results in less waste, which increases the production efficiency.

The barrier film may be created for aseptic filling in EVOH packaging. By doing this, less energy is required for processing. Reduced energy use equals lower expenses. It is desirable to have lightweight constructions with a barrier coating. Compared to bulky packing, they enable the delivery of more items, thus increasing efficiency.

2. PP, EVOH packaging: Which one is better?

PP, EVOH packaging: Which one is better?

Polypropylene (PP) and EVOH are both commonly used materials in the food packaging industry, but they have different properties and uses. Here's a more in-depth comparison between the two food packaging materials:

2.1. Barrier properties

EVOH is known for its exceptional barrier properties, particularly its high oxygen barrier which is ideal for packaging perishable food products such as meats, dairy products, and prepared foods. This high oxygen barrier helps to prevent spoilage and extends the shelf life of food products. 

On the other hand, PP has relatively low barrier properties, and while it provides some level of protection against oxygen and moisture, it is not as effective as EVOH. PP is often used as a structural material in combination with EVOH or other barrier materials to create multi-layer packaging structures that offer the desired combination of strength, barrier, and flexibility.

2.2. Chemical resistance

PP is highly resistant to chemicals and is often used to package foods and beverages that contain acidic or fatty components. PP is able to withstand the aggressive nature of these food components and maintain its physical properties, hence, becoming a suitable material for packaging products such as sauces, dressings, and oils. 
Meanwhile, EVOH has limited chemical resistance, and while it is not recommended for packaging products that contain aggressive chemicals, it can be used to package products that are less acidic or contain fewer fatty components.

2.3. Transparency

PP is a clear, translucent material that is often used for food packaging applications where the visibility of the product is important. The transparency of PP allows consumers to see the food product inside, then becomes the most suitable plastic material for packaging products such as fruits, vegetables, and baked goods. 

In contrast, EVOH is not as transparent as PP, but it can be made to be semi-transparent. In multi-layer packaging structures that combine PP and EVOH, the PP layer provides the desired transparency, while the EVOH layer provides the necessary barrier protection.

2.4. Cost

PP is relatively low cost compared to EVOH and is often used as a structural layer in multi-layer packaging structures to reduce costs. The low cost of PP makes it an ideal material for packaging applications where cost is a major consideration. EVOH is a more expensive material due to its high barrier properties, but it is typically used as a barrier layer in multi-layer packaging structures to provide the desired level of protection.

Generally speaking, neither PP nor EVOH is "better" in all applications. The choice of material depends on the specific needs of the food packaging application, such as the type of food being packaged, the desired shelf life, and the cost constraints. For applications where a high level of barrier protection is required, EVOH is the better choice, while for applications where transparency and chemical resistance are important, PP is a better choice. In many cases, multi-layer packaging structures that combine PP and EVOH offer the best combination of properties, providing the desired balance of strength, barrier, and cost-effectiveness.

3. About EuroPlas

European Plastics Joint Stock Company (EuP) is the world's leading plastic filler manufacturer based in Vietnam. We offer a wide variety of plastic materials suitable for many uses including: plastic additives, bioplastics, color masterbatch, compound engineering plastics, filler masterbatch, bio filler.

EuP is committed to providing the best user experience. All materials and production processes of Europlas have been tested for quality and are trusted by thousands of customer partners from many countries around the world. Therefore, when choosing our products, customers are completely assured of the product quality and services. 

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