Choosing EVOH Co-extruded or Laminated Films: A Guide from Process to Price

In the world of high-performance packaging, Evoh (ethylene-vinyl alcohol copolymer) has become a key material for ensuring product freshness, safety, and extended shelf life. As a crucial element in barrier packaging, EVOH has evolved beyond a basic raw material to a technology that defines packaging quality.

However, when it comes to choosing between the two main EVOH-based packaging options—high-barrier co-extruded films and laminated films—many companies find it challenging to balance “superior performance,” “cost control,” and a “sustainable future.” So, how can companies make the right decision to achieve optimal packaging value?

1.Understanding the Processes: Key Differences

1.1 EVOH Co-extruded Films: A "One-Step" Approach

In co-extrusion, multiple extruders melt EVOH plastic together with polyolefins like PE or PP, which are then combined in a die and cooled into a multi-layered film. The key advantage here is that the layers bond through molecular fusion, eliminating the need for adhesives, which means there are no risks of solvent residue. This process results in a clean, pure structure.

1.2 EVOH Laminated Films: A "Carefully Assembled" Process

In contrast, laminated films begin with pre-formed EVOH cast films or other substrates. These are then bonded to materials such as aluminum foil, nylon (PA), or PET using dry or solventless lamination techniques. This method offers great flexibility, allowing for the creation of complex multi-layer structures like "Aluminum Foil + EVOH + PE."

In essence, co-extruded films prioritize efficiency and purity, while laminated films focus on combining various functionalities and strengths.

2.Performance Comparison: The Real Barrier Properties

2.1 Oxygen Barrier Performance:

In co-extruded films, EVOH acts as the core barrier layer, protected by outer polyolefin layers. This structure allows for long-lasting, stable oxygen barrier performance (usually ≤2.0 cm³/m²·day). In laminated films, when combined with aluminum foil, the oxygen barrier can be significantly stronger (≤0.1), nearly eliminating oxygen transmission.

2.2 Mechanical and Chemical Strength:

Laminated films, thanks to their multi-material construction, offer superior puncture resistance, tear strength, and better chemical resistance to oils, acids, and bases. Co-extruded films, however, are more flexible and resistant to stretching fatigue, making them ideal for packaging that will be frequently squeezed (such as juice pouches).

2.3 Transparency and Aesthetics:

Co-extruded films tend to be more transparent, allowing consumers to see the product clearly, which can enhance its appeal. Laminated films, particularly those with aluminum foil, are opaque but provide a glossy metallic finish and excellent light-blocking properties.

2.4 Environmental Impact and Recycling:

This is an increasingly important consideration. Co-extruded films typically have a simpler structure (e.g., PE/EVOH/PE), which makes them easier to recycle in plastic streams and aligns with the global trend toward “single-material” packaging design. Laminated films, due to the inclusion of multiple materials (plastics, aluminum, adhesives), are harder to separate and recycle, which places a greater environmental burden on them.

3.Cost Breakdown: More Than Just Material Costs

It’s often noted that EVOH co-extruded films tend to be 20%-30% less expensive than laminated films with similar barrier properties. This cost difference is driven by several factors:

3.1 Raw Material Efficiency:

Advanced multi-layer co-extrusion technology—such as five-layer or seven-layer systems—allows for a thinner EVOH layer (as little as 8% of the total thickness) while still providing excellent barrier properties. This drastically reduces the amount of expensive EVOH resin used. In laminated films, the EVOH layer is typically used in its full thickness, resulting in higher material consumption.

3.2 Production Efficiency and Energy Consumption:

Co-extrusion is a one-step process, eliminating multiple stages found in lamination, such as coating, drying, and curing. This leads to faster production, lower energy consumption, and reduced labor costs. Additionally, modern co-extrusion lines equipped with temperature control and automatic thickness monitoring ensure minimal waste.

3.3 Economies of Scale and Industry Clusters:

Large-scale production allows for significant cost savings. For example, packaging industry hubs in regions like Hebei and Jiangsu in China benefit from well-established supply chains and concentrated production capabilities, which reduce costs across the board—from raw material procurement to equipment maintenance. Local companies often lock in raw material prices through long-term contracts and share technological innovations, driving continuous cost optimization.

3.4 Environmental Compliance Costs:

With regulations like the EU Packaging and Packaging Waste Regulation (PPWR) coming into force, non-recyclable packaging may face higher taxes or market access restrictions. Choosing co-extruded films, which are easier to recycle, can be seen as a forward-thinking investment that helps avoid potential future compliance costs.

4.Expert Q&A (FAQ)

Q1: How can I quickly determine whether to choose co-extruded films or laminated films?

A1: A simple guideline is as follows: If the primary packaging requirement is to “prevent oxygen ingress” (e.g., preserving freshness), and the contents are not highly corrosive (e.g., strong acids or oils), co-extruded films are an efficient and cost-effective choice. If the packaging needs to provide “comprehensive protection” (oxygen, moisture, light barriers, puncture resistance) or protect against corrosive contents, laminated films are the better option. Ultimately, testing should be done to validate the choice.

Q2: How does the thickness of the EVOH layer affect the final packaging cost?

A2: The thickness of the EVOH layer has a significant impact on cost. EVOH material is one of the most expensive components of the packaging. By optimizing the design through multi-layer co-extrusion technology, the EVOH layer can be reduced to a micrometer level, which is key to controlling costs. For instance, placing the EVOH layer in the middle of a five-layer structure and carefully controlling its thickness can reduce EVOH usage by 15%-20% compared to a three-layer structure, while maintaining or even improving barrier performance through symmetric design.

Both EVOH co-extruded films and EVOH laminated films have their own technical advantages and market applications. The key to making the right choice lies in understanding the packaging’s functional requirements, budget constraints, and sustainability goals. Every material decision along the way is a balance of technology, cost, and responsibility.