Definition

DuPont Pyralux is the dominant material family for flexible circuits, built on Kapton polyimide film. Pyralux AP (adhesiveless all-polyimide) bonds polyimide directly to copper without adhesive for the best controlled impedance and thermal performance, with Tg ~340°C and Dk ~3.4. Pyralux LF (acrylic-based) has 35+ years of proven reliability. Pyralux HT handles operating temperatures >225°C for EV power modules. Pyralux TK combines FEP fluoropolymer with Kapton for Dk <3.0 in high-frequency flex applications. Standard dielectric thicknesses run 0.5-6.0 mils (7.0-20 mils special order). Specify Pyralux AP for multilayer flex and rigid-flex requiring controlled impedance. Pyralux complies with IPC-4204/11.