AIR-FILTER MEDIUM

A sheet-shaped air-filter medium obtained by laminating first needle-punched nonwoven fabric, which comprises core-sheath type heat-fusible short composite polyester fibers and non-core-sheath type short polyester fibers, second needle-punched nonwoven fabric, which comprises core-sheath type heat-fusible short composite polyester fibers and non-core-sheath type short polyester fibers, and spun lace nonwoven fabric comprising core-sheath type heat-fusible short composite polyester fibers and non-core-sheath type short polyester fibers, the air-filter medium having undergone thermal fusion bonding and having a sheet thickness, as measured in accordance with JIS-P-8118, of 1.6-2.3 mm, a stiffness, as measured in accordance with JIS-L-1096 8.22. method 1A (Gurley method), of 70-110 mN, and a basis weight of 240-340 g/m2. The first needle-punched nonwoven fabric, the second needle-punched nonwoven fabric, and the spun lace nonwoven fabric have respective specific basis weights. In the core-sheath type heat-fusible short composite polyester fibers of each of the first and second needle-punched nonwoven fabric and the spun lace nonwoven fabric, the polyesters corresponding to the sheaths have melting points of 100-160°C, and the polyesters corresponding to the cores have melting points of 250-260°C. The non-core-sheath type short polyester fibers of each of the first and second needle-punched nonwoven fabric and the spun lace nonwoven fabric have melting points of 250-260°C. Un support de filtre d'air en forme de feuille obtenu par stratification d'un premier tissu non tissé aiguilleté, qui comprend des fibres courtes en polyester composites thermofusibles et des fibres courtes en polyester de type gaine non-core, un second tissu non tissé aiguilleté, qui comprend des fibres courtes de polyester composites thermofusibles de type gaine core et des fibres courtes de polyester de type à gaine non-core, et un tissu non tissé par hydroliage comprenant des fibres courtes de polyester composite thermofusibles de type gaine core et des fibres de polyester courtes de type à gaine non-core, le support du filtre d'air ayant subi une liaison par fusion thermique et ayant une épaisseur de feuille, telle que mesurée selon la norme JIS-P -8118, de 1,6 à 2,3 mm, une rigidité tel que mesuré conformément à JIS-L -1096 8,22. Méthode 1A (procédé Gurley), de 70 à 110 mN, et un poids de base de 240 à 340 g/m 2 Le premier tissu non tissé aiguilleté, le second tissu non tissé aiguillet