| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter medium for an air filter capable of suppressing pressure loss in an air filter unit and the air filter unit using the filter medium.SOLUTION: The filter medium for the air filter for collecting dusts in an air flow has a preliminailyy collecting layer collecting a part of the dusts in the air flow, and a main collecting layer arranged in the downstream side of tha air flow to the preliminarily collecting layer and collecting the dust having passed through the preliminarily collecting layer and comprising a polytetrafluoroethtlene porous membrane The preliminarily collecting layer is a nonwoven cloth or a fiber layer structure constituted of a fiber material manufactured by one of a melt-blown methd, an electro-spinning method, a sea-island method or a hybrid method of them, the average fiber diameter of the fiber material is 0.8 μm or more and 2 μm or less. |
