Conductive papers for electromagnetic shielding

Two types of conductive papers were developed for preventing or reducing electromagnetic interference (EMI), and their shielding effectiveness was evaluated. One of the type of conductive papers were made by mixing pulp and metallized fillers such as mica, glass fibers and synthetic fibers, of which the surfaces are coated with nickel alone or copper and nickel double layers by electroless plating. The other type of conductive paper was prepared by coating nickel or copper/nickel double layers directly on to the surface of polyester paper by electroless plating. The conductive paper with 80 g/m² of basis weight, which were prepared by mixing 40 wt% NiCu-PET (nickel/copper-coated polyester fibers) and 60 wt% synthetic polyethylene pulp, showed over 40 dB shielding effectiveness between 10 MHz and 1 GHz.