Coextruded
Principle
This process consists of extruding several materials together in the same tooling so that each of the materials can be separately confined in a specific zone of the section.
Why use coextrusion ?
- To include X-ray opaque lines in the wall of a transparent tube.
- To have an internal layer which is compatible with the conveyed liquid, and an external layer which determines the mechanical aspects of the tube.
- To allow a coloured marker line.
- To combine the mechanical properties of two materials.
Process limitations
- Limitations are associated with the compatibility of the materials: in most cases, the different materials must adhere together.
- When the tube is manufactured, the temperatures must be compatible as well as the rheological behaviours of the materials.
Examples
- Tubing for epidural catheters (x-ray opaque lines)
- Extension tubing for sensitive medicine (coextruded PE/adhesive/PVC )
- High-pressure extension line