Patent ID: 8372175

Claim:
A pleated filter comprising a self-supporting porous monocomponent monolayer matrix containing a bimodal mass fraction/fiber size mixture of intermingled larger size and smaller size continuous monocomponent polymeric fibers of the same polymeric composition, the fibers being bonded to one another at at least some points of fiber intersection and the matrix forming rows of folded or corrugated pleats and having an average initial submicron efficiency of at least 15% at a 1.52 meters/sec face velocity and wherein the histogram of mass fraction vs. fiber size in μm exhibits a larger size fiber mode of about 10 to about 40 μm; wherein the monolayer matrix comprises a generally uniform distribution of fiber sizes throughout a cross-section of the monolayer matrix, and wherein the larger and smaller size fibers are meltblown fibers.