US Patent 7858163 Molded monocomponent monolayer respirator with bimodal monolayer monocomponent media

A molded respirator is made from a monocomponent monolayer nonwoven web containing a bimodal mass fraction/fiber size mixture of intermingled continuous monocomponent polymeric microfibers and larger size fibers of the same polymeric composition. The respirator is a cup-shaped porous monocomponent monolayer matrix whose matrix fibers are bonded to one another at at least some points of fiber intersection. The matrix has a King Stiffness greater than 1 N. The respirator may be formed without requiring stiffening layers, bicomponent fibers, or other reinforcement in the filter media layer.