Robert Foley, President
Amna Rana, Technical Sales Manager
Designing a flexible catheter shaft used to involve a PTFE liner plus braiding plus multiple Pebax® layers. Now, a laser-cut hypotube and a single jacket of readily available Pebax heat shrink tubing can streamline the process.
Cobalt Polymers’ Pebax heat shrink tubing is a key component in the design of a new generation of flexible, low-profile interventional devices used for delivery and access in applications including neurovascular, cardiac, and peripheral vascular surgery.
Interventional device design today is trending away from braided shafts towards laser-cut hypotubes. Thanks to cutting technology advances that have reduced cost, it’s now possible to create a thinner, higher-performance device at a cost comparable to traditional methods.
Pebax heat shrink tubing is playing a major role in this trend. This flexible, durable, thin-wall heat shrink tubing offers a unique and effective solution for jacketing laser-cut hypotubes. The Pebax tubing remains on and integrates with the device, eliminating the cumbersome reflow process with traditional FEP heat shrink tubing.
Eliminating the reflow process saves time and reduces manufacturing yield loss. Sourcing fewer materials streamlines your supply chain, and leveraging readily available Pebax heat shrink tubing eliminates the need to source scarce materials. Eliminating FEP also reduces lead times and environmental impact.
Key to the performance of Pebax heat shrink tubing is its uniquely strong adhesion. When brought to its shrinking temperature, it will thermally bond to an underlying material, whether it’s a metal such as stainless steel or a thermoset plastic such as polyimide. This is what allows Pebax heat shrink tubing to substitute for commonly used reflow jackets. It also eliminates delamination issues and the need for an adhesive or tie layer.
Unlike other heat shrink tubing, Pebax heat shrink tubing allows the substrate below to remain flexible. With the thinnest walls in the industry, Pebax heat shrink tubing can maintain a low device profile. Wall thicknesses are available below 0.0250 mm (0.001”), with diameters ranging from 0.1778 mm (0.007”) to 6.35 mm (0.250”). Typical wall thickness for a robust jacket is in the range from 0.025 mm – 0.075 mm (0.001” – 0.003”).
Cobalt Polymers’ heat shrink tubing is available in durometers between 40D and 72D, providing multiple options for varying flexibility needs. It also comes in a range of colors, including custom colors.
Here’s a real-life example of an ideal application for Pebax heat shrink tubing. A global health care company designed a next-generation advanced diagnostic catheter with a metal core. This tiny (2 Fr) catheter required a thin, flexible, protective polymer cover that would bond to and move with the underlying metal structures, including a laser-cut hypotube and a welded cable tube.
Using a traditional reflow process would have been problematic, as the metal core and thin walls would have made for a very difficult reflow process, leading to high costs for materials and labor as well as compromised yields.
The company worked with Cobalt Polymers to find the optimal durometer of Pebax heat shrink tubing. No other single material offered such thin (.001”/.025 mm) walls in a flexible polymer in a heat shrink format for easy application. The 6-foot/1.8 m length allowed for a single, continuous outer jacket with uniform thickness and flexibility. This design put the structural change in the underlying metal rather than in the outer polymer layer, resulting in:
- Thinner walls
- Higher performance
- Ease of manufacturing
Cobalt Polymers’ Northern California facility has the manufacturing capacity to meet your heat shrink tubing needs. Pebax heat shrink tubing can be spooled or cut to length and can be customized through pad printing. Many sizes of Pebax heat shrink tubing are in stock and ready to ship, with custom colors, durometers, and lengths also available. To request samples, visit the Cobalt Polymers website or order small quantities at Chamfr.com. To learn more, visit www.cobaltpolymers.com.
Pebax is a registered trademark of Arkema Inc.
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