Incorporating barrier packaging materials for thermoformed and form fill seal extended shelf-life food packaging applications is typically achieved through either a multi-layer coextrusion process or an extrusion lamination process.
At ICPG, we develop and produce a wide range of structures—from monolayer extruded sheet and rollstock, to multilayer symmetric or asymmetric coextruded structures in rollstock form. Our state-of-the-art coextrusion line is designed for precision material processing suitable for food packaging (processed foods, dairy-cheese, yogurt, coffee, baby food, etc.) and medical packaging (wound care, surgical kits, etc.). These applications require protection from external elements, like oxygen, moisture, and UV exposure, as well as extended shelf-life performance.
How Barrier Packaging is Incorporated into Rollstock Structures
The two primary methods for incorporating barrier materials into extruded rollstock are coextrusion and extrusion lamination.
Coextrustion
Coextrusion is the process where two or more plastic materials (with similar or dissimilar characteristics and behavior) are extruded as one. In a standard monolayer sheet extrusion process, one material is fed and extruded through a die. In the coextrusion process multiple extruders and multiple materials (depending on the structure), feed different materials through the melt pipes where they form a laminar flow before being welded together through coextrusion feed block and die technology.
By combining multiple material layers, barrier packaging benefits from the distinct properties of each material. These multilayer structures provide superior protection, extended shelf-life, and cost efficiencies.
During the extrusion process, the cooling rolls—also known as the stack rolls or chill rolls—regulate temperature and help define sheet thickness and surface texture. Specialty surface finishes such as matte, sand matte, and hair cell enhance the final structure.
Benefits of coextrusion for barrier packaging include:- Superior oxygen and moisture barrier protection
- Extended shelf-life performance
- Cost efficiencies through material blending
- Structural enhancements and custom surface finishes (matte, sand matte, hair cell, etc.)
Although new compounded materials are advancing, coextrusion continues to expand material capabilities by combining the best properties of different plastics. This makes it a leading choice for high-performance food packaging applications.
Extrusion Lamination
Extrusion lamination is the process of applying a multilayer coextruded lamination film to a desired substrate (such as paper, plastics, ceramic, metal, etc.) via heat, pressure or a combination of both. Laminates are very thin extruded film structures designed to improve strength, stability, and barrier performance.
This method is particularly beneficial when enhancing mechanical, barrier, or chemical properties, or when improving the visual appeal of the substrate. Different lamination techniques—lamination, wet lamination, and thermal lamination—can be used depending on performance needs.
Regardless of the lamination method used, in all cases the webs are combined at a lamination nip i.e. typically two rolls pressed against each other under a controlled temperature, pressure and gap. Since the web is combined using just the heat and pressure from the stack/chill roll, it is important that the lamination web has low thermal properties (low melting point) so that the preheating caused from the stack roll and pressure will thermally laminate and create a strong bond soon after it exits the stack roll and pull roll system.
ICPG offers extrusion thermal laminated materials using PE, PP, PS, with added lamination to enhance oxygen, UV, or decorative performance. This makes lamination particularly valuable when improving aesthetics or specific mechanical properties.
Coextrusion vs. Lamination: Which Process Should You Choose?
The choice between coextrusion and lamination depends on factors such as cost, quality, sustainability, and application requirements.
| Coextrusion | Extrusion Lamination |
|
High output rate with exceptional bond and material properties. |
Moderate output rate for effective bond strength. |
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Complex equipment requiring continued maintenance. |
Less equipment to maintain if added on line as an extrusion thermal lamination process. |
|
Longer setup time. |
Setup time is short and easy. |
|
High capital investment for equipment, materials and storage. |
Lower capital investment and more diverse range of lamination equipment and film options. |
|
Shorter lead time as material is readily available in stock. |
Longer lead time as lamination films is custom and outsourced. |
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Ideal process for cost effective products as reprocessed/recycled material can be easily integrated back in the system. |
Less energy consumption compared to multiple extrusion system with coextrusion process, but materials cannot be re-integrated into structure. |
|
Rollstock specifications limited to equipment capabilities for gauge, width, and materials. |
Lamination film can be outsourced in varying gauge, width and materials based on application. |
Coextrusion vs Lamination FAQs
Q: What is the main difference between coextrusion and lamination?
A: Coextrusion combines multiple materials into a single multilayer structure during extrusion, while lamination bonds a thin film to a substrate using heat and pressure.
Q: Which process is more cost-effective for barrier packaging?
A: Coextrusion is generally more cost-effective because recycled material can be reintegrated, but lamination requires lower upfront investment and offers more flexibility with outsourced films.
Q: When should I choose lamination over coextrusion?
A: Lamination is a good choice when you need shorter setup times, lower initial costs, or flexibility in film options. It’s often used for decorative finishes or when sourcing specialty barrier films.
Q: Which process provides better barrier performance?
A: Both processes can achieve adequate barrier properties depending on the application, but coextrusion is best for high-barrier shelf-stable structures, while lamination allows customization with specialized films like oxygen or decorative UV barriers.
Final Thoughts on Barrier Packaging Processes
Coextrusion is generally the most cost-effective and versatile process for producing barrier packaging materials. However, extrusion lamination offers advantages when flexibility, appearance, or cost efficiency are more critical.
Understanding the trade-offs in coextrusion vs. lamination helps food brands, medical companies, and packaging engineers select the process that best supports their shelf-life, sustainability, and performance goals.
For more information on barrier packaging materials and processes contact ICPG or download our free Guide to Barrier Materials and Processes:
