Definition
A process that extrudes multiple polymer melts together to form a multilayer film in a single step.
Applications
- PE films with tie layers
- Barrier coex with EVOH
- Specialty sealant structures
Benefits
- Integrates layers efficiently
- Improves layer adhesion control
- Can reduce lamination steps
Industry Examples
- Medical: coex sealant webs with controlled SIT and peel properties for pouches.
- Industrial: coex heavy liners with tough outer layers and chemical-resistant inner layers.
- Electronics: produces multilayer static-shielding films integrating dissipative and conductive layers in a single extrusion process.
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FAQ
Q: How many layers can coex have?
A: Commonly 3–9+ depending on equipment.
Q: When choose coex vs lamination?
A: Coex for integrated films; lamination for combining dissimilar substrates like PET and foil.