Kapton® FN Polyimide Disk

Kapton® FN Disk is a precision-cut circular component in DuPont Kapton® FN — a composite of Kapton® HN polyimide film with Teflon® FEP fluorocarbon resin on one or both faces — available in diameters from 4 mm to 50.8 mm in three gauges (0.030 mm, 0.035 mm, 0.050 mm). It provides a ready-to-use circular piece of heat-sealable polyimide-FEP composite for direct integration into lamination stacks, capacitor assemblies, sensor housings, and electromechanical sub-assemblies, without requiring in-house cutting from flat film.

The Teflon® FEP layer on one or both faces of the disk enables heat-seal bonding to adjacent film layers or copper surfaces under heat and pressure, without adhesive. Film-to-film peel strengths of 700 g/in (2.7 N/cm) and film-to-copper peel strengths of 300 g/in (1.2 N/cm) minimum are achieved. In disk applications this means the component can be integrated into a lamination stack or capacitor assembly and sealed in place thermally — eliminating adhesive bonding steps and their associated outgassing, thickness, and process complexity, which is particularly valuable in compact assemblies where every layer adds to overall thickness.

The 120FN (0.030 mm) grade carries FEP on both faces at the highest minimum dielectric breakdown in the range, allowing heat-seal bonding on either surface — the correct choice for symmetric lamination assemblies and capacitor insulation disks where bilateral bonding is required. The 150FN (0.035 mm) grade carries FEP on one face only, providing directional bonding for stacked assemblies where one surface must seal and the other present a bare polyimide interface. The 200FN (0.050 mm) grade is available in single- and double-sided FEP constructions and offers the greatest mechanical robustness — the correct choice for motor insulation components and transformer lamination elements where greater thickness and abrasion resistance are required.

All gauges are certified to MIL-P-46112B and ASTM D-5213. The UL thermal index across all gauges is 200–220°C for mechanical properties and 220–240°C for electrical properties under UL file E39505. These certifications confirm the material's suitability for aerospace, military, and industrial electrical insulation applications.

Kapton® FN Disk maintains continuous service from −269°C to +400°C, with shrinkage at 400°C controlled to 2.5% maximum in both directions. This ensures the disk maintains its geometry and dielectric performance through thermal processing cycles and in service at elevated temperatures in motor, transformer, and aerospace insulation applications.

Kapton® FN Disk is used in symmetric lamination assemblies and capacitor insulation, where 120FN disks provide bilateral heat-seal bonding and a high minimum dielectric breakdown voltage in a compact circular geometry; stacked assemblies with directional bonding, where 150FN disks seal on one face and present bare polyimide on the other; motor insulation components and transformer lamination elements, where 200FN disks provide the greatest mechanical robustness and abrasion resistance in the range; sensor housings and electromechanical sub-assemblies, where the ready-to-use disk geometry allows direct integration without additional cutting or forming; and sample-scale heat-seal strength measurement and dielectric breakdown characterisation across all three gauges.

Yes. The disk geometry and ASTM D-5213-certified DuPont substrate make it well suited to sample-scale heat-seal adhesion strength measurement, dielectric breakdown testing, and thermal lamination characterisation across the three gauges. The pre-cut circular format eliminates sample preparation variability when testing requires a defined circular geometry.

Choose disk when the component is circular in plan and requires a pre-cut piece for direct integration — lamination stack inserts, capacitor insulation layers, sensor housing seals, and motor insulation components are natural disk applications. Film sheet is appropriate when the geometry is non-circular or larger than the stock disk diameter range. Coil is the correct format when the process runs continuously from a roll — automated winding, tape-laying, and roll-to-roll lamination lines all require coil format rather than individual pieces.

Kapton® FN Disk is available in all three gauges in diameters from 4 mm to 50.8 mm. Diameter tolerance is ±0.5 mm; thickness tolerance is ±20%. Custom diameters and non-standard sizes are available on request. Request a quote with your gauge, diameter, FEP construction, and required quantity.