Patent ID: 7727915

Claim:
A filtration medium comprising: (a) a nonwoven airlaid multilayer substrate having a basis weight of from about 35 gsm to about 500 gsm comprising, based on the total weight of the substrate, from about 30 weight percent to about 95 weight percent matrix fibers and from about 5 weight percent to about 70 weight percent of a binder comprising (A) a first layer comprising synthetic matrix fibers and having a top surface and a bottom surface, (B) a second layer having a top surface and a bottom surface, the second layer comprising cellulosic matrix fibers and binder with the top surface of the second layer contacting the bottom surface of the first layer, (b) optionally, a dusting layer of latex on the bottom surface of the second layer having an outer surface, and (c) a pressure sensitive adhesive.