Conductive pulp fiber sheet-prepared waste newspaper pulp fibers treated by electroless nickel plating and its electric field shielding effect

In order to explore new applications of recovered waste paper, we prepared electrically conductive fibers by plating waste newspaper pulp (WNP) fibers. Further, we mixed them with unplated WNP fibers and filtered the mixture to obtain a conductive pulp fiber sheet, which was to be used for electromagnetic compatibility (EMC) purposes. For the plating of WNP fibers, we used an electroless nickel plating method. We also plated pulp fibers recovered from fine paper, pulp fibers recovered from milk carton, and bleached softwood kraft pulp fibers, which were used for comparison with the plated WNP fibers. All of the four types of plated, recovered waste paper pulp fibers had high conductivity, i.e., an electrical conductivity of 0.1 S/m or more and a conductance of 0.02 S or more. The conductive pulp fiber sheet made of WNP fibers had an electric field shielding effect of 30 dB or more at 10–1000 MHz, provided that the ratio of the plated WNP fibers in the sheet was 40 % or more. Therefore, our conductive WNP fiber sheet is effective in EMC.