Polyimidfilmen

Polyimidfilmen are thin, flexible films made from polyimide polymers, renowned for high thermal stability and excellent electrical insulation. They are typically produced by imidizing polyamic acid precursors, formed from the reaction of aromatic dianhydrides with diamines. The polyamic acid is cast as a film from suitable solvents and then thermally cured to form the polyimide film. Common thicknesses range from about 12 to 125 micrometers.

Polyimidfilmen exhibit high glass transition temperatures, commonly above 250°C, with continuous service temperatures in the 260–300°C range and short-term exposure above 350°C. They offer excellent dielectric properties, high breakdown strength, low dielectric constants, and low dissipation factors, making them well suited for electrical insulation. They also possess outstanding chemical resistance, dimensional stability, and low moisture uptake, along with good radiation resistance and flame retardancy. Mechanically, they remain strong and flexible over a wide temperature range.

Applications include insulation and protection in flexible electronics, cables and connectors, and insulating layers in flexible printed circuits. They are used in aerospace, automotive, and other demanding environments where high-temperature performance is required, as well as in solar cells and MEMS packaging. The best-known polyimide film is Kapton, marketed by DuPont; other brands such as Upilex and Pyralux are used for copper-clad polyimide laminates in flexible circuits.

Processing considerations involve compatible solvents and adhesives due to high imidization temperatures, as well as careful handling to minimize moisture uptake and warping. Recycling options are limited, and polyimide films are generally not recyclable in the same way as some other plastics.