| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter medium for an air filter, a filter pack, and air filter unit capable of ensuring not only high collection efficiency and low pressure loss but also a high collection amount, and a method of manufacturing such a filter medium for an air filter.SOLUTION: In a filter medium 1 for an air filter configured so that a preliminary collection material 10, a first porous membrane 31, and a second porous membrane 32 are disposed side by side in order from an upstream side, a pressure loss of the preliminary collection material 10 is equal to or higher than 15 Pa and lower than 55 Pa when air is passed through the preliminary collection material 10 at a flow rate of 5.3 cm/second, collection efficiency thereof for NaCl at a particle size of 0.3 μm is equal to or higher than 25% and lower than 80%, a thickness thereof is equal to or smaller than 0.4 mm, a PF value is equal to or higher than 7 and equal to or lower than 15, and a value of {(the PF value of the preliminary collection material)/(a PF value when the first porous membrane 31 and the second porous membrane 32 are stacked)} is equal to or higher than 0.20 and equal to or lower than 0.45.SELECTED DRAWING: Figure 1 |
