Low CTE & High Dimensional Stability Polyimide Film for FPC

Engineered specifically for flexible printed circuit board fabrication, this low coefficient of thermal expansion (Low CTE) polyimide (PI) film serves as a high-performance foundational substrate. Tailored to meet mainstream mass-production requirements of the FPC industry, the material delivers dependable dimensional stability and superior compatibility with flexible processing workflows. It is widely utilized in flexible circuit manufacturing for consumer electronics, smart wearable gadgets, automotive electronic systems and other prevalent fields.

The product’s most prominent feature is its exceptional low thermal expansion stability. It efficiently resolves typical production defects of conventional PI films during high-temperature FPC manufacturing processes, such as thermal expansion and contraction, board warping and dimensional shifting. Its thermal expansion coefficient is well matched with copper foil during lamination, hot pressing, curing and reflow soldering procedures. This greatly minimizes common manufacturing issues including layer delamination, surface wrinkling and circuit misalignment, effectively boosting production yield and positioning precision, and fully complying with the fabrication standards of high-precision fine-line flexible circuits.

Adopting high-purity polyimide raw materials and optimized film-forming craftsmanship, this PI film integrates reliable physical and chemical comprehensive properties. It boasts robust mechanical toughness and outstanding flex resistance, capable of enduring long-term cyclic bending and torsion without cracking or structural deformation, perfectly fitting the dynamic service conditions of flexible electronic components. Furthermore, it delivers excellent dielectric insulation, continuous high-temperature resistance and anti-aging capability, maintaining stable structural and electrical performance under prolonged high-temperature operation to secure the safety and long-term reliability of FPC circuits.

Featuring excellent universal process adaptability, this low CTE PI film is fully compatible with standard FPC manufacturing processes, including copper cladding, adhesive bonding, laser cutting, precision etching and surface finishing. It requires no special process parameter adjustment, enabling stable and efficient large-scale mass production. Compared with ordinary standard PI films, it presents obvious advantages in dimensional consistency, process tolerance and long-term operational reliability, making it an ideal base material for mid-to-high-end precision FPCs, ultra-thin flexible circuits and high-frequency flexible circuit boards.

Designed for practical industrial application, this film focuses on essential practical performance without unnecessary functional redundancy. It achieves an optimal balance between process stability, end-product reliability and production cost efficiency, perfectly catering to the manufacturing needs of both commercial and industrial-grade flexible printed circuits.

Our polyimide films are categorized into yellow PI film and black PI film, covering diverse application demands of FPC products with standardized industrial thickness specifications:

Available thickness ranges from 5μm to 100μm, with mainstream industrial specifications of 12.5μm, 25μm and 50μm. Featuring steady basic physical properties and reliable insulating capability, it is widely applicable for conventional FPC surface protection and circuit packaging scenarios.

Mainstream specifications include 25μm and 50μm. While inheriting the inherent high-temperature resistance and flexibility of polyimide materials, this variant provides superior light-blocking performance, specially developed for high-precision optoelectronic FPC applications.

As a core protective and insulating material for flexible printed circuits, PI film is extensively used in consumer electronics and optoelectronic device manufacturing. Its major functional applications are listed below:

• Circuit Protection: Laminated on the surface of FPC conductive circuits to isolate air and moisture, preventing circuit oxidation, corrosion and external mechanical damage. It stabilizes circuit operating performance and prolongs the service lifespan of flexible circuit boards.
• Electrical Insulation: Provides outstanding dielectric insulation performance, effectively preventing short circuits and electric leakage between adjacent circuits, which is suitable for insulation isolation and encapsulation of high-density precision FPC circuits.
• Light Shielding (Black PI Film Exclusive): Ideal for devices with strict light-shielding requirements such as camera modules and display backlight units. It effectively blocks stray light interference, eliminates light leakage and astigmatism issues, and ensures stable imaging and display effects of optoelectronic components.
• Flexible Bending Protection: Tolerates frequent repeated bending and twisting movements. It is commonly applied to flexible structural areas of terminal products, including hinge parts of foldable smartphones and bending connection zones of wearable devices, protecting FPC circuits from fracture and failure during dynamic bending operations.