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Abstract

A filtering element for air filter is formed by joining an upstream layer arranged upstream in flow direction of air integrally with a downstream layer located downstream in the flow direction of the air. The upstream layer collects dust from the air and the downstream layer supports the upstream layer. The upstream layer is formed through press forming of a nonwoven fabric formed of fibers having an average diameter of 0.5 .mu.m to 2.5 .mu.m. The thickness of the upstream layer is set to 0.005 mm to 0.1 mm, and the porosity of the upstream layer is set to 78% to 92%. The downstream layer is normally formed by a filter paper layer. The press forming is performed preferably at 20.degree. C. to 160.degree. C. and 1 MPa to 5 MPa. The mass per unit area of the upstream layer is preferably 1 g/cm.sup.2 to 15 g/cm.sup.2. The density of the fibers forming the nonwoven fabric is 0.9 g/cm.sup.3 to 1.5 g/cm.sup.3.

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First Claim