What Is Medical Polyimide Tubing? Properties, Uses and Applications (2026)

Quick Answer: What Medical Polyimide Tubing Is Used For

Medical polyimide tubing is a thin-wall polymer tube used inside catheters, microcatheters, and other minimally invasive devices where high tensile strength, chemical resistance, and dimensional precision are required within a very small diameter. It is most commonly specified for microcatheter shafts, guidewire liners, and delivery system components because it can be extruded with inner diameters as small as 0.10mm while still holding tight tolerances under repeated flexing.

This guide covers the material properties, manufacturing considerations, and application data behind medical polyimide tubing, with visual comparisons to help device engineers and sourcing teams evaluate polyimide against other common tubing materials such as PTFE and nylon-based liners.

What Is Medical Polyimide Tubing?

Polyimide tubing (PI tubing) is produced by applying a liquid polyimide resin in successive coating layers onto a removable mandrel, then curing each layer at high temperature until the desired wall thickness is achieved. This coating-based process, rather than traditional extrusion alone, is what allows polyimide tubing to reach ultra thin wall thicknesses while still maintaining structural integrity at very small diameters, which is difficult to achieve with many other polymer tubing materials.

Core Material Characteristics

• High tensile strength relative to wall thickness, supporting pushability in catheter shafts
• Strong dimensional stability across repeated flexing and torque cycles
• Chemical resistance to most solvents and sterilization processes used in device assembly
• High temperature tolerance, supporting long-term operation above 350°C and short-term exposure up to 450°C
• Good biocompatibility for applications with internal patient contact

Because of this combination of strength and precision, polyimide tubing is widely specified as the outer or intermediate structural layer in multi-layer catheter tubing constructions, often paired with a lubricious inner liner material.

Why Polyimide Is Used in Catheter and Microcatheter Construction

Catheter and microcatheter tubing must balance three competing needs: a small enough profile to navigate narrow vasculature, enough column strength to be pushed through the body without kinking, and enough flexibility to track through curved anatomy. Polyimide tubing addresses this balance better than many alternative materials at very small diameters, which is why it is a common choice for microcatheter tubing construction.

As illustrated above, polyimide's tensile strength is substantially higher than PTFE, nylon, or Pebax at comparable wall thickness, which allows device engineers to reduce wall thickness while still meeting structural requirements. This is particularly valuable in microcatheter tubing, where every fraction of a millimeter of wall thickness directly affects the achievable inner lumen diameter and overall device profile.

Is Polyimide Better Than PTFE? A Side-by-Side Comparison

Polyimide and PTFE are often used together rather than as direct substitutes, since each material contributes different performance characteristics to a finished catheter tubing assembly. The radar chart below compares both materials, plus a PI/PTFE composite construction, across five performance criteria on a relative 1-10 scale.

Polyimide clearly leads in tensile strength, thin-wall capability, and structural rigidity, which is why it is frequently used as the outer structural layer of a catheter shaft. PTFE, in contrast, scores highest on lubricity, making it the preferred material for the inner lumen surface where guidewires and other devices need to slide with minimal friction. A PI/PTFE composite construction combines both strengths, using the PI layer to prevent deformation and support pushability while the PTFE layer keeps the inner wall smooth, which is why composite constructions are common in high-performance catheter tubing designs.

Standard Dimensions and Wall Thickness Reference

Because polyimide tubing is built through a layered coating process rather than direct extrusion alone, wall thickness can be controlled with high precision. The table below outlines typical dimensional ranges referenced during early-stage device design.

While the standard inner diameter range for most polyimide tubing applications falls between 0.10mm and 2mm, mass production capability has expanded in recent years to support inner diameters up to 5.00mm for larger delivery system and access tubing components.

Temperature and Chemical Resistance Performance

Temperature resistance is a key differentiator for polyimide tubing, particularly during device manufacturing steps such as reflow bonding, laser processing, or sterilization cycles that involve elevated temperatures. The line chart below shows relative mechanical stability of polyimide tubing across a rising temperature range compared with a standard nylon-based tubing material.

Polyimide tubing retains a high percentage of its mechanical stability even as temperatures climb toward 300°C and beyond, supporting a long-term operating temperature above 350°C and short-term exposure up to 450°C. Nylon-based tubing, by comparison, begins losing structural stability well before reaching these temperatures, which limits its suitability for manufacturing processes that involve heat-based bonding or high-temperature sterilization steps.

Biocompatibility and Sterilization Considerations

For any component with direct or indirect patient contact, biocompatibility testing and sterilization compatibility are baseline requirements. Polyimide tubing intended for medical device use is generally evaluated against recognized biological evaluation frameworks referenced in ISO 10993, the international standard for biological evaluation of medical devices, which covers cytotoxicity, sensitization, and irritation testing relevant to catheter and microcatheter components (International Organization for Standardization, ISO 10993).

Sterilization Compatibility

Polyimide tubing generally maintains dimensional and mechanical stability across common sterilization methods used in medical device manufacturing, including ethylene oxide (EtO), gamma irradiation, and steam autoclave processes, due to its high temperature resistance and chemical stability. This broad compatibility is one reason polyimide is frequently selected for components that must remain dimensionally consistent after terminal sterilization.

• Ethylene oxide (EtO) sterilization: commonly used for finished catheter assemblies
• Gamma irradiation: suitable given polyimide's chemical and radiation stability
• Steam autoclave: supported by polyimide's high-temperature performance range

Where Medical Polyimide Tubing Is Applied

Polyimide tubing is specified across a range of minimally invasive device categories. The table below summarizes common application areas and the primary reason polyimide is selected for each.

Across nearly all of these categories, the underlying requirement is consistent: engineers need a tubing material that holds a precise, repeatable lumen dimension after sterilization while withstanding the mechanical stresses of navigation through the vasculature, which is the core strength profile of medical grade polyimide tubing.

Custom Polyimide Tubing: What Device Engineers Can Specify

Custom medical tubing OEM projects typically involve adjusting several parameters beyond basic inner and outer diameter. A proprietary PI resin formulation approach allows manufacturers to tune modulus, tensile strength, elongation, and color to match a specific device requirement.

Commonly Customized Parameters

1. Modulus and elongation tuning to balance flexibility with pushability for a specific catheter design
2. Wall thickness reduction through a multi-pass coating process for ultra thin wall polyimide tubing
3. Color coding for multi-lumen or multi-component device assemblies
4. Adhesion enhancement, allowing direct bonding to materials such as Nylon and TPU without additional surface treatment
5. Composite layering with PTFE for applications requiring both strength and inner-wall lubricity

Direct bonding capability without surface treatment is a practical advantage during device assembly, since it reduces the number of processing steps needed to join polyimide tubing to adjacent components in a multi-material catheter build.

Working With a Medical Tubing Manufacturer: What to Verify

Device manufacturers sourcing polyimide tubing components should confirm a supplier's process control, quality documentation, and application-specific experience before finalizing a project. A few key verification points can help reduce qualification risk during device development.

• Confirmation of ISO certification and a documented quality management system for medical tubing production
• In-house extrusion, coating, and post-processing capability rather than outsourced sub-steps
• Experience producing precision extruded polyimide tubing at the specific diameter range required
• Support for OEM and ODM development workflows, including sample iteration before full production
• Documented sterile tubing handling procedures for cleanroom or controlled-environment production

Ningbo Linstant Polymer Materials Co., Ltd. has operated since 2014 as an OEM and ODM medical tubing manufacturer, now employing over 400 employees and specializing in extrusion processing, coating, and post-processing technologies for medical polymer tubing. The company's proprietary PI resin approach allows customization of modulus, strength, elongation, and color for polyimide tubing, and its coating process supports thinner wall thicknesses while its polyimide tubing offers direct bonding compatibility with materials such as Nylon and TPU without surface treatment. Beyond the standard 0.10mm to 2mm inner diameter range, the company is capable of mass-producing polyimide tubing with inner diameters up to 5.00mm, and its tubing is engineered for long-term operating temperatures above 350°C with short-term resistance up to 450°C, alongside good biocompatibility for medical device applications.

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