| 摘要 |
PROBLEM TO BE SOLVED: To provide an electret filter medium using a porous dielectric sheet made from a polyolefin resin that has been sufficiently and highly converted into an electret, including the inside.SOLUTION: In an electret filter medium, a value of O/C which is a molar ratio of an oxygen atom (O) and a carbon atom (C) on the surface of a porous dielectric sheet made from a polyolefin resin is 0.003-0.03.SELECTED DRAWING: None |
