Patent ID: 9180394
Filing Date: 2015-11-10
Classification: B01D,B32B,D04H,Y10T

Abstract:
1. A multilayer composite air filter material, consisting of: a first upstream ply, wherein the at least one upstream ply has a weight per unit area of 20 to 100 g/m one supporting ply comprising a continuously extruded spunbonded nonwoven connected to said at least one upstream ply and includes continuous filaments having a titer of higher than 5 dtex; and a second upstream ply having a continuously extruded spunbond nonwoven having continuous nanofilaments having a mean diameter of about 50 to 300 nm; and wherein the supporting ply has a mean pore diameter at least two times the size of a mean pore diameter of the upstream ply; a mean pore diameter of the support ply is at least twice as large as the mean pore diameter of the first or second upstream ply, at least a portion of the continuous filaments of the first or second upstream ply are homogeneously twisted or interwoven with at least a portion of the continuous filaments of the supporting ply so as to continuously and uniformly bond said first or second upstream ply to said supporting ply without introducing ducts through which dust particles can pass through the at least one upstream ply and into the supporting ply; and said multilayer composite has a weight per unit area of about 300-500 g/m