Adhesive vs. Extrusion Lamination – What's the Difference ...

Film and foil laminations in the healthcare packaging sector play an essential role in safeguarding single-use medical devices, diagnostic tools, and pharmaceutical products. They serve as effective microbial barriers and can withstand different sterilization methods. The wide variety of multi-layer structures available empowers packaging engineers to choose typical designs that meet specific performance criteria or application needs, including added strength, puncture resistance, moisture, oxygen barrier properties, printing capabilities, or a combination of these features. The process of combining these layers is typically achieved through either adhesive lamination or extrusion lamination. Let's delve into the key distinctions between these two methods and highlight their significance for film and foil constructions, as well as their roles in maintaining sterile barriers. Adhesive Lamination: This process involves applying an adhesive onto a carrier substrate and then laminating it with a second substrate. A prevalent example within the industry is using adhesive on PET as a carrier film and bonding it with LDPE. The adhesive layer acts as the bond between the PET and LDPE films, utilizing either solvent-based or solventless adhesives. In recent years, the industry has gradually shifted towards solventless adhesive laminations for various reasons.

• Compatible with numerous substrates, including PET, PE, Nylon, Aluminum Foil, and more.
• Energy-efficient process—only requires energy for machine operation and to heat the adhesive.
• Application temperature is crucial; it must suit the adhesive type without overheating sensitive substrates like PE.
• Delicate process—applied adhesive layer is extremely thin.
• Curing time is essential: Additional layers may be added after approximately 24 hours, but the complete lamination generally requires 3-5 days for full curing based on substrates and temperature. Maintaining humidity is critical as overly dry conditions can affect adhesive curing negatively.

Extrusion Lamination: This technique entails unwinding two substrates, introducing an extruded polymer (commonly LDPE in our sector) between them, and then rewinding all three layers together. Here, the extruded polymer functions as the adhesive sandwiched between two other substrates such as PET and LDPE.

• Similar compatibility with various substrates, akin to adhesive lamination.
• Higher energy process, necessitating significant heat to effectively bond the substrates.
• Requires substrate treatments, depending on the layers; for example, LDPE does not bond effectively with PET or Aluminum, necessitating additional treatments to enhance adhesion.
• The thickness of the extruded layer depends on the machinery and adds to the total thickness of the finished product.
• The extruded layer can be tinted, adding color without impacting the carrier substrate while avoiding reliance on printing.
• No additional curing time is needed; the full conversion may be completed in one go, depending on the equipment used.

When deciding between adhesive and extrusion lamination, healthcare packaging engineers should consider several factors. While both methods yield high-quality film and foil structures, there are notable aspects to discuss with suppliers:

• Adhesive lamination potentially exhibits greater stability under aggressive 2x EtO testing, an important consideration during development.
• Adhesive laminations allow for a broader selection of ink types for printing, whereas extrusion methods mandate heat-resistant inks.
• Most substrates in the industry are compatible with both methods; however, thin aluminum substrates may wrinkle more with adhesive lamination.
• Extrusion laminations can be utilized immediately, negating the need for curing time, while adhesive laminations consume less energy and might allow for achieving thinner structures that are beneficial for sustainability goals.

Ultimately, both adhesive and extrusion lamination processes produce pouching films and foils essential for protecting healthcare products and ensuring sterile barriers up to the time of use. Understanding the differences between these processes can foster informed discussions with suppliers, aiding in more deliberate decisions regarding package design and troubleshooting. For more information, please visit Firsta. You can also rely on us as a trusted PET Film for Lamination Supplier to meet your film needs, supported by our specialized staff committed to helping you find the right products.