| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology for improving durability of a filter medium while preventing significant degradation of permeability.SOLUTION: A filter medium (20) includes a first polytetrafluoroethylene porous membrane (11), a first permeable support material (12), a second polytetrafluoroethylene porous membrane (13), and a second permeable support material (14). A surface of the filter medium (20) is formed of the first polytetrafluoroethylene porous membrane (11). Adhesive strength (A) between the first polytetrafluoroethylene porous membrane (11) and the first permeable support material (12) measured by a 180° friction test is higher than 1.2 N/25 mm, and is higher than adhesive strength (A) between the first permeable support material (12) and the second polytetrafluoroethylene porous membrane (13) measured by the 180° friction test.SELECTED DRAWING: Figure 1 |
