Patent ID: 8029723

Claim:
A method for making shaped filtration articles, which method comprises: a) forming a monocomponent nonwoven web by: i) flowing first and second fiber-forming materials of the same polymeric composition through a single meltblowing die comprising first and second die cavities in respective fluid communication with first and second sets of orifices in a meltblowing die tip of the single melt-blowing die, wherein the first fiber-forming material flows at a lesser flow rate or viscosity through the first die cavity and first set of orifices to form a set of smaller size filaments and the second fiber-forming material flows at a greater flow rate or viscosity through the second die cavity and second set of orifices to form a set of larger size filaments; ii) commingling the smaller size and larger size filaments while attenuating them into fibers between converging streams of air or other fluid; iii) collecting the attenuated fibers as a nonwoven web containing a meltblown bimodal mass fraction/fiber size mixture of intermingled continuous microfibers and larger size fibers of the same polymeric composition, and b) molding, pleating or otherwise shaping the web into a self-supporting non-planar porous monocomponent monolayer matrix of fibers bonded to one another at least some points of fiber intersection.