| 摘要 |
PROBLEM TO BE SOLVED: To provide an air filter material prevented from a clogging caused by collected dust and capable of suppressing the rise in pressure loss. SOLUTION: In the air filter material including a polytetrafluoroethylene porous membrane 1 and an air permeable porous fiber material 2, the air permeable porous fiber material 2 with a fiber diameter of 1-15μm, a void ratio of 70% or more and a basis wt. of 60 g/m2 or more is disposed on the upstream side of the polytetrafluoroethylene porous membrane 1. As the air permeable porous fiber material 2, a nonwoven fabric is pref. and, as the material quality thereof, polyethylene, polypropylene or polyethylene terephthalate can be used.
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