Patent ID: 8496722

Claim:
A nonwoven fabric comprising a multilayered spunbonded filaments, said nonwoven fabric being suitable for an air filter and said multilayered structure comprising an air inlet part and an air outlet part of an air filter, wherein the air inlet part comprises first filament fibers and the air outlet part comprises second filament fibers, wherein the first filament fibers are polyester filament fibers having an average fineness of 4 to 6 denier (De′), wherein the second filament fibers are polyester filament fibers having an average fineness of 2 to 3 denier (De′), wherein the weight per unit area of the nonwoven fabric is 130 to 200 g/m 2 , and wherein the thickness of the nonwoven fabric is 0.4 mm to 0.8 mm.