Co-extrusion brings separate molten resin streams together in one die so each layer can do a different job. One layer may seal, another may add toughness, and another may slow oxygen transmission. A tie layer can bond materials that would otherwise separate. More layers are useful only when they solve a measured package requirement.
Common Co-Extruded Film Structures
Our co-extrusion lines run three to seven layer structures. These are the ones buyers ask for most.
| Structure | Layers | Used for |
|---|---|---|
| LLDPE / LDPE blend | 3 | Strong general packaging film and bags |
| PE with a metallocene sealant | 3 | Food film that has to seal fast and tight |
| PE / tie / nylon | 3 to 5 | Tough, puncture resistant vacuum packaging |
| PE / tie / EVOH / tie / PE | 5 | Oxygen barrier for meat, cheese and sensitive foods |
| PE / tie / nylon / EVOH / nylon / tie / PE | 7 | Barrier plus toughness in one film |
Need a structure outside our lines? We source it through partner extruders and manage it for you. Need finished barrier bags instead of film? Our sister company Serv-Pak gets them made.
Start With The Package, Not A Layer Count
For a quote or trial, identify the product being packed, required shelf life, oxygen or moisture target, package format, seal partner, sealing conditions, target total gauge, width, and planned printing or lamination. Add the test method and acceptance limit for each critical property. Those inputs make a proposed structure testable instead of merely impressive on paper.
What Each Layer Has To Prove
A PE/tie/EVOH/tie/PE structure is one example: polyethylene can provide seal surfaces, EVOH can provide oxygen barrier, and the tie resin can hold the unlike layers together. It is not a default recipe for every product. The choice and thickness of each layer have to match the package and the way it will be filled, sealed, stored, and handled.
Ask for trial results on the finished structure: total and layer gauge, seal strength, barrier under the specified conditions, puncture or tear resistance where needed, and bond integrity after converting. A resin data sheet does not establish the performance of the final film. Our film spec sheet guide explains how to read those measurements before comparing suppliers.