Polyimide (PI/Kapton) is the premium choice for 80% of flex PCBs, offering superior thermal resistance, mechanical strength, and solderability. Polyester (PET/Mylar) is a cost-effective alternative for static, low-temperature applications. Choose polyimide for anything involving soldering, heat, or repeated flexing; choose polyester for simple, low-cost static flex circuits.
Recommended Material
Polyimide for Most Applications
Polyimide is the standard material for professional flex PCBs. Its exceptional thermal stability makes it compatible with all soldering processes, and its mechanical properties support dynamic flexing applications.
Polyester is appropriate for cost-sensitive, static applications where soldering isn't required. It's commonly used with conductive inks and pressure-fit connections.
The most critical difference is thermal resistance. Polyimide maintains stability up to 400°C, while polyester deforms above 80°C. This affects manufacturing options and application suitability.
For applications involving repeated movement, polyimide significantly outperforms polyester. PI can achieve millions of flex cycles, while PET is limited to thousands before cracking.
Our engineers help you select the optimal material based on your application requirements.
We offer standard, high-Tg, and specialty polyimide materials for demanding applications.
We'll recommend PET where appropriate to reduce costs without compromising performance.
Thermal cycling, flex testing, and reliability validation services available.
Material-specific design rules to maximize performance and manufacturability.
Incoming material inspection and certification documentation provided.
No, standard soldering processes exceed PET's thermal limits. PET circuits use conductive adhesives, silver ink printing, or mechanical connections like ZIF connectors.
Polyimide is a high-performance engineering polymer requiring specialized manufacturing. Its superior properties (thermal stability, mechanical strength, chemical resistance) justify the premium for demanding applications.
Kapton is DuPont's brand name for polyimide film. Other manufacturers produce equivalent polyimide materials under different names. The properties are similar across suppliers.
Generally no. Automotive environments often exceed 80°C, and automotive quality standards typically require polyimide. PET might work for some cabin applications with temperature control.
Rarely. Multilayer flex typically requires lamination processes with heat, which is incompatible with PET. Polyimide is the standard choice for multilayer flexible circuits.
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