Patent ID: 7754041

Claim:
A process for making a pleated filter comprising: a) forming a monocomponent monolayer nonwoven web 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 web having a Gurley Stiffness of at least 100 mg, b) forming rows of pleats in the nonwoven web, and c) cutting the pleated web to a desired size and shape to form a self-supporting pleated filter element comprising a porous monocomponent monolayer matrix of fibers bonded to one another at at least some points of fiber intersection and having an average initial submicron efficiency of at least 15% at a 1.52 meters/sec face velocity, wherein the histogram of mass fraction vs. fiber size in μm exhibits a larger size fiber mode of about 10 to about 40 μm.