Electret fiber sheet and its manufacturing method, as well as air filter filter media and filters

摘要

PROBLEM TO BE SOLVED: To provide an electret fiber sheet having high dust collecting characteristics, which is suitably used for an air filter filter medium. The present invention is an electret fiber sheet composed of a fiber structure composed of polyolefin-based resin fibers having an average single fiber diameter of 0.1 to 8 μm, and contains a hindered amine-based compound in the electret fiber sheet. When the amount is α (mass%) and the content of the triazine-based compound in the electret fiber sheet is β (mass%), 0.1 ≦ α + β ≦ 5 is satisfied, and the following formula (1) is satisfied. 3.0 × 10-4 ≦ Σ (IE / IO) ≦ 3.0 × 10-3 ... (1) Here, IE is an electlet sheet derived from the hindered amine compound and / or the triazine compound. It is the sum of the peak intensities of the positive secondary ions on the surface, and IO is the peak intensity of the positive secondary ions on the surface of the electlet sheet derived from the polyolefin resin. [Selection diagram] None