The present invention generally relates to the design and manufacture of nanofiber layers, webs, films, or membranes that may be self-supporting and can function as standalone products. More particularly, the present invention relates to a microporous nanofiber films and the use of such films in a wide variety of products and applications, including applications where physical property tuning is typically limited. Generally, the microporous films of the present invention can function as a standalone nanofiber membrane or can be bonded to other microporous films to produce a layered stacked film stack with customizable properties. Unlike conventional microporous films available in today's market, the microporous films of the present invention can be lighter, require less raw material cost to produce, and can improve operating performances in a variety of applications.

A method of making nonwoven webs comprising providing a spinneret including a pattern of conduits forming an extrusion region; directing only a first stream of molten propylene polymer into a region adjacent the first side of the spinneret, directing only a second stream of molten propylene polymer into a region distal to the first side of the spinneret, extruding only the first stream propylene polymer through the exit openings in a first zone where the exit opening comprises exit ports in the first zone having a first density; extruding only the second stream propylene polymer through the exit openings of a second zone where the exit opening comprises exit ports in the second zone having a second density less than the first density; and the second zone is distal to the first side with the first zone being between the second zone and the first side.

Methods and (articles of manufacture therefrom) including forming an elastic film from a polymer composition; tensioning the elastic film to a stretch ratio of between 2 and 6 in the MD; laminating the elastic film to an extensible facing to provide an elastomeric laminate having a CD hysteresis loss of 70% or less and an MD hysteresis loss of 50% or less.

A nonwoven fabric having polylactic acid-containing fibers forming a nonwoven web is provided. The web has a side having an alternating pattern of individualized bonded areas which bonded areas define rods arranged in the cross direction of the web. The rods are arranged so that in the machine direction of the web no uninterrupted regions exist along the web while in the cross direction the arrangement of rods defines uninterrupted regions that extend continuously along the web, the alternating pattern of individualized bonded areas defines a non-bonded area. The web has a basis weight from 5-50 g/m.sup.2, the surface of the bonded areas is from 5-20% of the total surface of the side, and the surface of the non-bonded area is from 80-95% of the total surface of the side. Processes for forming the nonwoven fabric and an absorbent article including the nonwoven fabric are also provided.

A nonwoven fabric having polylactic acid-containing fibers forming a nonwoven web is provided. The web has a side having an alternating pattern of individualized bonded areas which bonded areas define rods arranged in the cross direction of the web. The rods are arranged so that in the machine direction of the web no uninterrupted regions exist along the web while in the cross direction the arrangement of rods defines uninterrupted regions that extend continuously along the web, the alternating pattern of individualized bonded areas defines a non-bonded area. The web has a basis weight from 5-50 g/m.sup.2, the surface of the bonded areas is from 5-20% of the total surface of the side, and the surface of the non-bonded area is from 80-95% of the total surface of the side. Processes for forming the nonwoven fabric and an absorbent article including the nonwoven fabric are also provided.

A filter medium (10) for filtering a fluid, in particular for use in an interior air filter (32), comprises a spun-bonded nonwoven formed at least in part of multi-component segmented pie fibers (1) having at least a first plastic component (2) and a second plastic component (3). The multi-component fibers (1) are largely non-split and in order to manufacture same, segmented pie filaments are spun in a spun-bonding process (S4) to form a spun-bonded nonwoven (10). The segmented pie filaments then form the multi-component fibers (4), the first plastic component (2) and/or the second plastic component (3) being made in particular of a polypropylene.

A filter medium (10) for filtering a fluid, in particular for use in an interior air filter (32), comprises a spun-bonded nonwoven formed at least in part of multi-component segmented pie fibers (1) having at least a first plastic component (2) and a second plastic component (3). The multi-component fibers (1) are largely non-split and in order to manufacture same, segmented pie filaments are spun in a spun-bonding process (S4) to form a spun-bonded nonwoven (10). The segmented pie filaments then form the multi-component fibers (4), the first plastic component (2) and/or the second plastic component (3) being made in particular of a polypropylene.

The present invention is directed toward a method of making a composite structure including receiving a substantially planar nonwoven spunbond layer including a plurality of multicomponent fibers, thermally bonding the nonwoven spunbond layer at a first bond temperature, laying down a meltblown layer on top of the thermally bonded nonwoven spunbond layer to form an intermediate structure, and thermally bonding the intermediate structure at a second bond temperature to form a final composite structure. Composite structures including a spunbond layer and a meltblown layer, wherein the composite structure has a tensile strength of at least about 130 N/2.54 cm in both machine and cross directions, a tear strength of at least 3.0 N/2.54 cm, and an LRV of about 2.0 or higher are also provided herein.

The present invention is directed toward a method of making a composite structure including receiving a substantially planar nonwoven spunbond layer including a plurality of multicomponent fibers, thermally bonding the nonwoven spunbond layer at a first bond temperature, laying down a meltblown layer on top of the thermally bonded nonwoven spunbond layer to form an intermediate structure, and thermally bonding the intermediate structure at a second bond temperature to form a final composite structure. Composite structures including a spunbond layer and a meltblown layer, wherein the composite structure has a tensile strength of at least about 130 N/2.54 cm in both machine and cross directions, a tear strength of at least 3.0 N/2.54 cm, and an LRV of about 2.0 or higher are also provided herein.

Multi-component fibers or filaments that are ribbon shaped are provided having polymer components positioned in a side-by-side fashion. For example, the multi-component fibers may be bicomponent fibers having ribbon shape. The polymer components of the fibers are selected to have differential shrinkage behavior. Nonwovens are also provided that are manufactured from such ribbon shaped multi-component fibers or filaments.