Kapton® HN Polyimide Film

Kapton® HN is DuPont's general-purpose polyimide film and the ASTM D-5213 reference grade — the baseline against which all other Kapton® grades are measured. It combines a thermal range no other polymer film can match (−269 °C to +400 °C continuous service), strong electrical insulation, radiation resistance, dimensional stability, and chemical resistance in a single material. Its surface is untreated, which suits applications that do not require adhesion to copper or other laminates. For most insulation, research, masking, and structural film applications, HN is the natural starting point.

Kapton® HN maintains its electrical insulation, mechanical integrity, and dimensional stability from −269 °C (liquid helium temperature) up to +400 °C continuous service. This is a range no other commercially available polymer film covers. At the cryogenic end it is used in superconducting magnet wiring, MRI systems, and dilution refrigerator harnesses. At the high-temperature end it serves in aerospace wire insulation, motor slot liners, and Class H electrical systems. The same film handles both extremes — a property that simplifies material selection in thermally demanding designs.

Kapton® HN has an exceptionally high dielectric strength and volume resistivity, with a stable, low dielectric constant across a broad frequency range. These properties do not degrade significantly with temperature cycling, age, or repeated mechanical flexing — which is why it is specified for flexible printed circuits, capacitor dielectrics, transformer insulation, and high-voltage miniaturised assemblies where insulation failure over the service life of the product is not acceptable.

Yes. Kapton® HN has proven radiation tolerance and is used in nuclear reactor instrumentation, particle accelerator beam diagnostics, and space systems where the film is exposed to sustained ionising radiation. In high-energy physics facilities it serves as a detector window, particle beam diagnostic film, and ion-beam imaging substrate. It is also used in radiation-curing composite manufacturing where its structural and electrical properties must be maintained after dose accumulation that would degrade most polymer alternatives.

Kapton® HN offers good resistance to greases, fuels, aromatic hydrocarbons, halogenated hydrocarbons, and ketones — the solvents and process fluids most commonly encountered in electronics manufacturing and aerospace maintenance. It has poor resistance to concentrated acids, alkalis, and alcohols, and should not be used in applications involving prolonged contact with these substances. Its resistance to ultraviolet light is also poor; for UV-exposed applications, protective overcoating or UV-stable adhesive bonding should be considered.

Kapton® HN can be die-cut, laser-machined, and precision-drilled. Laser micromachining produces clean, burr-free edges with minimal heat-affected zone and is the preferred method for small features, fine-pitch slots, and microfluidic structures. For larger cuts and sheet sizing, blade cutting and punching are also effective. The film responds to etching, coating, laminating, and metallising. Its untreated surface bonds less readily to copper and adhesive systems than FPC or HPP-ST; where adhesion is the primary concern, one of those surface-treated grades is more appropriate.

Kapton® HN is sterilization-resistant and has been used in flexible medical sensors, wearable diagnostic devices, catheters, and body-worn electronics where its combination of thin profile, thermal stability, and polyimide chemistry suits external and body-worn device construction. It is not suitable for permanent implantation in the human body or direct contact with internal body tissues or fluids — applications requiring implant-grade biocompatibility should be evaluated under ISO 10993.

Kapton® HN carries a UL 94 V-0 flame rating — the highest classification for non-burning behaviour in UL testing. It will not melt, ignite, or propagate flame, making it suitable for aerospace wiring, motor insulation, and battery module applications where fire safety standards require V-0 rated materials throughout the construction.

Kapton® HN is used most heavily in aerospace wiring and thermal blankets, cryogenic instrumentation and superconducting systems, flexible printed circuits and capacitor dielectrics, nuclear reactor instrumentation, EV and hybrid vehicle battery modules and motor slot liners, high-temperature masking in soldering and thermal processing, and as a substrate for flexible heater elements. Its breadth of performance means it appears across almost every sector where conventional polymer films would fail under the combined demands of the environment.

Choose Kapton® HN when the application requires general-purpose electrical insulation, thermal stability, radiation resistance, or research-grade substrate use, and does not have a specific requirement for enhanced copper adhesion, reduced dimensional shrinkage, thermal conductivity, opacity, corona resistance, or ESD dissipation. HN is the lowest-cost Kapton® grade and the widest-thickness-range option. Upgrade to FPC if the application involves copper lamination and IPC-4202/1 compliance; to HPP-ST if dimensional precision under thermal cycling is paramount; to MT if heat dissipation is needed; to B if optical opacity is required; to CRC for inverter-duty motor insulation; or to 200RS100 for ESD control.

Yes. Kapton® HN Film is available in a range of standard sizes from 10 mm × 10 mm up to 500 mm × 500 mm, with thickness tolerance of ±20%. Custom cut shapes, precision-machined features, and laser-profiled outlines can be supplied through Goodfellow's cutting and microfabrication services. There is no minimum order quantity. Contact us with your dimensions and required thickness to confirm availability and lead time.