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Assignee3M Innovative Properties Company
InventorsJohn M. Brandner, William J. Kopecky, Seyed A. Angadjivand, James E. Springett, Timothy J. Lindquist
Estimating the term…
A porous monocomponent nonwoven web contains a bimodal mass fraction/fiber size mixture of intermingled continuous microfibers and larger size fibers of the same polymeric composition. There are at least five times as many microfibers as larger size fibers, and a histogram of the mass fraction of fibers vs. fiber size exhibits a larger size fiber mode greater than 10 μm. The web may be made by flowing fiber-forming material through a die cavity having larger size orifices and at least five times as many smaller size orifices to form filaments, attenuating the filaments into fibers and collecting the attenuated fibers to form the nonwoven web. The web is especially well suited to the manufacture of self-supporting three dimensional articles such as molded cup-shaped respirators and pleated air filters.
A porous monocomponent self-supporting nonwoven web comprising a monolayer matrix containing a bimodal fiber count/fiber size mixture of intermingled meltblown attenuated microfibers and meltblown attenuated monocomponent larger size fibers of the same polymeric composition, wherein there are at least five times as many microfibers as larger size fibers, wherein a histogram of the mass fraction of fibers vs. fiber size exhibits a larger size fiber mode of from about 10 μm, to 50 μm, wherein the larger size fibers have a maximum diameter of about 50 μm, and wherein the monolayer matrix comprises a generally uniform distribution of fiber sizes throughout a cross-section of the web.
Dependencies are inferred from the claim text.