Air filter material

Abstract

[Problem] To provide an air filter material in which spun bond nonwoven fabric and melt blown nonwoven fabric are laminated and integrated without reducing air permeability. [Solution] Spun bond nonwoven fabric comprises, as constituting filament, conjugate polyester continuous filaments having a cross-sectional shape of a nearly “Y4”-like shape. The continuous filament is composed of a nearly V-shape portion 6 in the nearly Y4-like shape, formed from low melting point polyester, and the other nearly+shape portion 5 therein, formed from high melting point polyester. The continuous filaments are heat-bonded with each other by the low melting point polyester. The spun bond nonwoven fabric is bonded by a powder type or spider web type hot melt adhesive agent with the melt blown nonwoven fabric.

1 . An air filter material comprising ultrafine fiber nonwoven fabric formed from ultrafine fibers and polyester nonwoven fabric formed from polyester continuous filaments, the ultrafine fiber nonwoven fabric being laminated and integrated with the polyester nonwoven fabric,
 wherein a shape of the polyester continuous filament in the cross section has the following nearly ‘Y4’ shape in which the bottom ends of the nearly ‘Y’ parts are connected to up, down, left and right:   
       
         
       
       and the polyester continuous filaments are heat-bonded with each other,
 the ultrafine fiber nonwoven fabric is bonded with the polyester nonwoven fabric by a powder type or spider web type hot melt adhesive agent which has a melting point lower than the melting points of the ultrafine fiber and the polyester continuous filament. 
 
     
     
         2 . The air filter material according to  claim 1 , wherein the polyester continuous filament is a conjugate polyester continuous filament which is composed that the nearly V shape portion of the nearly Y4 shape is formed from low melting point polyester and the other nearly+shape portion is formed high melting point polyester. 
     
     
         3 . The air filter material according to  claim 2 , wherein the conjugate polyester continuous filaments are bonded to each other by heat bonding of the low melting point polyester.