Kapton® FPC Polyimide Film

Kapton® FPC is DuPont's dedicated flexible circuit polyimide film. It shares the same base polymer chemistry as Kapton® HN — and the same −269 °C to +400 °C thermal range, high dielectric strength, radiation resistance, and UL 94 V-0 flammability rating — but has two key differences: a dual-sided adhesion treatment that promotes reliable bonding to both rolled-annealed and electrodeposited copper foils, and tighter dimensional stability under thermal processing. It is IPC-4202/1 compliant, making it the correct dielectric substrate choice wherever a qualification standard for flexible circuits is specified. Standard HN has an untreated surface and greater dimensional variability under heat — adequate for general insulation, masking, and research, but not optimised for fine-line copper lamination.

IPC-4202/1 is the industry standard for flexible base dielectric materials used in flexible printed circuit construction. Kapton® FPC's compliance with this standard confirms that it meets the dimensional stability, adhesion promotion, electrical, and thermal requirements that flex circuit manufacturers specify as a baseline for copper-clad laminate qualification. For aerospace, automotive, and medical flex circuit programmes where the substrate must be traceable to a published standard, FPC's IPC certification is often a hard procurement requirement.

Fine-line and HDI flex circuits fail in registration when the substrate shifts dimensionally during lamination, etching, or thermal cure cycles. Kapton® FPC's tighter control of residual shrinkage and superior lay-flat characteristics compared with HN reduce the pattern distortion that causes trace misalignment across multilayer stacks. Combined with its adhesion-treated surface — which promotes consistent peel strength to copper foil without delamination during thermal excursions — it is the substrate that allows fine-pitch, high-yield flex circuit fabrication.

Like all standard Kapton® grades, FPC has a continuous service range from −269 °C to +400 °C. This means it survives solder reflow, conformal coating cure, and all standard PCB processing steps without dimensional change or property degradation, and remains functional in the cryogenic environments of aerospace and scientific instrumentation at the other end of the scale.

Kapton® FPC is the standard substrate for flexible printed circuits in smartphones, tablets, and laptops (connector cables, camera module flex, antenna feeds); automotive ADAS sensor arrays and EV powertrain control flex; aerospace avionics flex interconnects and satellite sensor assemblies; medical wearable biosensors, hearing aid circuits, and body-worn diagnostic platforms; industrial robot continuous-flex cable chains; and HDI rigid-flex PCBs in defence electronics and high-performance computing modules. Any application where a polyimide substrate must flex dynamically, hold fine-pitch registration through thermal processing, and bond reliably to copper specifies FPC by default.

Yes. Kapton® FPC maintains its mechanical integrity through sustained repeated flexing without crack initiation or delamination from the copper layer — a critical requirement for foldable displays, articulating robotic harnesses, drawer connector cables, and any assembly subject to millions of flex cycles in service. Its elongation and tensile modulus are balanced to absorb repeated bending stress without fracturing or causing trace cracking at the substrate-copper interface.

Kapton® FPC is compatible with standard flex circuit processing chemistry including the etchants, plating solutions, and adhesive systems used in copper-clad laminate manufacture. It can be laser-drilled and ablated for via formation, die-cut or laser-profiled for outline shaping, and processed through roll-to-roll lamination lines. Its surface treatment is formulated to bond to acrylic and epoxy adhesive systems as well as to both rolled-annealed and electrodeposited copper foils.

Kapton® FPC is sterilisation-resistant and has been used in body-worn medical sensor platforms, wearable diagnostic devices, and hearing device flex circuits. 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.

Choose FPC when the primary requirements are copper adhesion and IPC-4202/1 compliance for flex circuit manufacture. It is the standard substrate selection for any application involving copper lamination and fine-line patterning. Choose HN instead if the application is a general insulation, masking, or research use that does not involve copper lamination and does not need a flex circuit qualification standard. Choose HPP-ST over FPC when dimensional stability is the overriding criterion — HPP-ST has lower residual shrinkage than FPC and is the grade for the most demanding registration-sensitive applications such as satellite sensor encapsulation and multilayer rigid-flex assemblies.

Kapton® FPC Film is available in thicknesses from 0.05 mm to 0.125 mm, in sizes from 10 mm × 10 mm up to 500 mm × 500 mm, with ±20% thickness tolerance and ±1 mm linear dimension tolerance for dimensions under 100 mm. Custom cut sizes, laser-profiled shapes, and non-standard thicknesses are available on request. Request a quote with your specification.