Why Do PTFE Etched Tubes Also Need a Tie-layer?

Why Do PTFE Etched Tubes Also Need a Tie-layer?

An invisible role that gives “inert PTFE” more possibilities. Meical catheter manufacturing, PTFE (Polytetrafluoroethylene) is almost always the liner of choice, thanks to its ultra-low friction coefficient, excellent chemical resistance, and superior electrical insulation.

However, PTFE has one “inborn flaw” — its inert surface, which makes it almost impossible to bond with other materials.To address this, the industry typically applies surface etching to PTFE, which increases surface activity and allows it to bond with polymers or adhesives. But that alone is not enough. To achieve stronger bonding stability and expand functionality, the Tie-layer was introduced.

What Is a Tie-layer?

A Tie-layer is essentially a functional intermediate layer.It bonds to the etched PTFE surface while also being compatible with the outer polymer layers, thus serving as a “bridging adhesive layer.”In other words, the Tie-layer is the key to ensuring that “modified PTFE” maintains a long-lasting and stable connection with a variety of outer materials.

Additional Roles of the Tie-layer in PTFE Etched Tubes

① Enhanced Bonding Strength
Although etching increases PTFE surface activity, there can still be risks of local delamination when bonded with outer materials. A Tie-layer further strengthens the adhesion, ensuring stable catheter structures during use.

② Resistance to Environmental Aging
Etching reduces PTFE’s natural inertness, making it more vulnerable to environmental factors like humidity and temperature. The Tie-layer acts as a protective barrier for the etched surface, extending the durability of the composite structure.

③ Improved Process Compatibility
With the Tie-layer, etched PTFE can bond more easily with materials such as PA, Pebax, or braided metal layers, widening the processing window and offering greater design flexibility.

More Than Just a Bonding Layer

The Tie-layer is not just an “adhesive layer”—it is the key enabler that allows PTFE etched tubes to achieve high-performance composite structures.

As a professional CDMO factory, we have accumulated extensive experience in PTFE etched tube + Tie-layer composite processes.

If you’d like to learn more about Tie-layer application solutions or request technical support, please contact the ECO Team.

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