Kapton® HN Polyimide Disk

Kapton® HN Disc is the same DuPont polyimide as Kapton® HN Film and Coil — the ASTM D-5213 general-purpose reference grade with a −269 °C to +400 °C thermal range, high dielectric strength, radiation resistance, and dimensional stability — supplied as a pre-cut circular piece. Available in diameters from 4 mm to 50.8 mm and thicknesses from 0.008 mm to 0.125 mm, it eliminates the blanking and handling step needed when cutting a circular piece from flat film sheet, and is ideal for low-volume, precision-assembly, or research applications where individual discs are required.

Kapton® HN Disc maintains its electrical insulation, mechanical strength, and dimensional stability from −269 °C (liquid helium temperature) to +400 °C continuous service — a range no other commercially available polymer film matches. This makes the disc format practical for use as a cryogenic electrical isolation washer at one extreme and as a high-temperature dielectric spacer or masking disc at the other.

The disc format is used wherever a circular polyimide component is needed without in-house cutting. Common applications include electrical isolation discs between conductive assemblies in high-voltage or RF systems, dielectric spacers in capacitor stacks and coil assemblies, circular substrates for thin-film deposition and sputtering target protection, particle detector window prototyping, beam diagnostic samples in accelerator physics, cryogenic spacers and washers in superconducting systems, and prototyping substrates for flexible circuit and sensor R&D where a defined circular geometry is required.

Kapton® HN Disc provides high dielectric strength, high volume resistivity, and a stable low dielectric constant across a broad frequency range. The disc geometry makes it straightforward to insert as an isolation layer in axial stack assemblies — between capacitor plates, transformer bobbin end faces, or stacked coil sections — where a consistent, pre-sized circular dielectric is needed to maintain repeatable layer-to-layer insulation.

Yes. Kapton® HN is the standard polyimide film for cryogenic wiring and instrumentation, rated to −269 °C. In disc form it serves as an isolation washer, spacer, or dielectric layer in dilution refrigerator wiring looms, superconducting magnet interconnects, and cryostat instrumentation assemblies, where its mechanical integrity and insulation performance are maintained at liquid helium temperatures without cracking or embrittlement.

Yes. Kapton® HN has low outgassing characteristics compatible with high-vacuum and ultra-high-vacuum environments — a requirement for particle physics instruments, synchrotron beamline optics, and satellite electronics assemblies. The disc format is used in beam diagnostic instruments and accelerator entrance windows where a pre-cut, dimensionally defined circular film is needed.

Kapton® HN is sterilization-resistant and has been used in flexible medical sensor components and body-worn electronics. It is not suitable for permanent implantation in the human body or direct contact with internal body fluids or tissues. Applications requiring implant-grade biocompatibility should be evaluated under ISO 10993.

Discs can be laser-machined to add holes, slots, and patterned apertures with clean, burr-free edges and minimal heat-affected zone — the preferred method for small features in thin polyimide. Die-cutting and precision punching are alternatives for larger features in thicker gauges. The film responds to etching, coating, metallising, and laminating where surface treatments are required for adhesion or electrical performance.

Kapton® HN Disc is available in diameters from 4 mm to 50.8 mm and thicknesses from 0.008 mm to 0.125 mm. Diameter tolerance is ±0.5 mm; thickness tolerance is ±20%. If you need a diameter outside this range or a non-standard thickness, Goodfellow's precision cutting service can produce discs to your specification. Contact us with your requirements.

Use disc format when the component is circular in plan and you need a pre-cut piece without in-house blanking — isolation washers, dielectric spacers, detector windows, and substrate discs for thin-film deposition are all natural disc applications. Film sheet is appropriate when geometry is non-circular, the piece is larger than the stock disc diameter range, or you need to cut multiple shapes from the same sheet. Coil is the correct format when your process runs continuously from a roll rather than using individual pieces.