Conductive papers containing metallized polyester fibers for electromagnetic interference shielding

Conductive papers were developed for preventing or reducing electromagnetic interference (EMI), and their shielding efficiency was evaluated. This typ e of conductive paper consists of wood pulp, synthetic pulp and metallized polyester fibers (0.5-2.0 mm long and 14 mu m in diameter) whose surfaces a re coated with nickel alone (Ni-PET) or copper and nickel double layers (Ni -Cu-PET) by electroless plating. In this report, the effect of the characte ristics of these metallized fibers, such as their conductivity, geometry an d the concentration of fibers in paper, which lead to high efficiency for s hielding effectiveness is discussed. For instance, one of the conductive pa pers (80 g/m(2)) which was prepared by mixing 40% Ni-Cu-PET and 60% synthet ic polyethylene pulp showed over 40 dB shielding effectiveness between 10 M Hz and 1 GHz.