Abstract: Processes for forming a yarn comprising a plurality of bicomponent filaments having a first region comprising a first polymer composition and a second region comprising a second polymer composition; the regions being distinct and present in the bicomponent filaments in a sheath-core structure or a side-by-side structure; wherein the first polymer composition comprises aramid polymer comprising 5 to 10 weight percent homogeneously dispersed discrete carbon particles and the second polymer composition comprises aramid polymer being free of discrete carbon particles and having at least one homogeneously dispersed masking pigment, the yarn having a total content of 0.5 to 5 weight percent discrete carbon particles.

Abstract: A flame-resistant garment comprising a flame-resistant fabric, and the flame resistant fabric, each comprising a yarn comprising a) 85 to 97 weight percent of a meta-aramid fiber component, and b) 3 to 15 weight percent of a fiber made from para-aramid polymer, based on the total amount of a) and b) in the yarn; wherein the meta-aramid fiber component is: i) 50 to 100 weight percent fiber made from a polymer blend of meta-aramid polymer and polyvinylpyrrolidone (PVP) polymer, the polymer blend comprising 88 to 95 weight percent meta-aramid polymer and 5 to 12 weight percent PVP polymer, and ii) 0 to 50 weight percent fiber made solely from meta-aramid polymer, based on the total amount of i) and ii) in the meta-aramid fiber component.

Abstract: A yarn comprising a plurality of bicomponent filaments having a first region comprising a first polymer composition and a second region comprising a second polymer composition, each of the first and second regions being distinct in the bicomponent filaments; each bicomponent filament comprising 5 to 60 weight percent of the first polymer composition and 95 to 40 weight percent of the second polymer composition; wherein the first polymer composition comprises aramid polymer containing 0.5 to 20 weight percent discrete homogeneously dispersed carbon particles and the second polymer composition comprises modacrylic polymer being free of discrete carbon particles; the yarn having a total content of 0.1 to 5 weight percent discrete carbon particles.

Abstract: Processes for forming a yarn comprising a plurality of bicomponent filaments having a first region comprising a first polymer composition and a second region comprising a second polymer composition; the regions being distinct and present in the bicomponent filaments in a sheath-core structure or a side-by-side structure; wherein the first polymer composition comprises aramid polymer comprising 5 to 10 weight percent homogeneously dispersed discrete carbon particles and the second polymer composition comprises aramid polymer being free of discrete carbon particles and having at least one homogeneously dispersed masking pigment, the yarn having a total content of 0.5 to 5 weight percent discrete carbon particles.

Abstract: A yarn comprising a plurality of bicomponent filaments having a first region comprising a first polymer composition and a second region comprising a second polymer composition; the regions being distinct and present in the bicomponent filaments in a sheath-core structure or a side-by-side structure; wherein the first polymer composition comprises aramid polymer containing 0.5 to 20 weight percent homogeneously dispersed discrete carbon particles and the second polymer composition comprises aramid polymer being free of discrete carbon particles and having at least one homogeneously dispersed masking pigment, the yarn having a total content of 0.5 to 5 weight percent discrete carbon particles.

Abstract: A yarn comprising a plurality of bicomponent filaments having a first region comprising a first polymer composition and a second region comprising a second polymer composition, each of the first and second regions being distinct in the bicomponent filaments; each bicomponent filament comprising 5 to 60 weight percent of the first polymer composition and 95 to 40 weight percent of the second polymer composition; wherein the first polymer composition comprises aramid polymer containing 0.5 to 20 weight percent discrete homogeneously dispersed carbon particles and the second polymer composition comprises modacrylic polymer being free of discrete carbon particles; the yarn having a total content of 0.1 to 5 weight percent discrete carbon particles.

Abstract: A yarn comprising a plurality of bicomponent filaments having a first region comprising a first polymer composition and a second region comprising a second polymer composition, each of the first and second regions being distinct in the bicomponent filaments; each bicomponent filament comprising 5 to 60 weight percent of the first polymer composition and 95 to 40 weight percent of the second polymer composition; wherein the first polymer composition comprises aramid polymer containing 0.5 to 20 weight percent discrete homogeneously dispersed carbon particles and the second polymer composition comprises modacrylic polymer being free of discrete carbon particles; the yarn having a total content of 0.1 to 5 weight percent discrete carbon particles.

Abstract: A yarn comprising a plurality of bicomponent filaments having a first region comprising a first polymer composition and a second region comprising a second polymer composition, each of the first and second regions being distinct in the bicomponent filaments; each bicomponent filament comprising 5 to 60 weight percent of the first polymer composition and 95 to 40 weight percent of the second polymer composition; wherein the first polymer composition comprises aramid polymer containing 0.5 to 20 weight percent discrete homogeneously dispersed carbon particles and the second polymer composition comprises modacrylic polymer being free of discrete carbon particles; the yarn having a total content of 0.1 to 5 weight percent discrete carbon particles.

Abstract: A yarn comprising a plurality of bicomponent filaments having a first region comprising a first polymer composition and a second region comprising a second polymer composition; the regions being distinct and present in the bicomponent filaments in a sheath-core structure or a side-by-side structure; wherein the first polymer composition comprises aramid polymer containing 0.5 to 20 weight percent homogeneously dispersed discrete carbon particles and the second polymer composition comprises aramid polymer being free of discrete carbon particles and having at least one homogeneously dispersed masking pigment, the yarn having a total content of 0.5 to 5 weight percent discrete carbon particles.

Abstract: A process for stripping chemically bonded spinning solvent from a solution-spun nonwoven web comprising the steps of providing a nonwoven web comprising solvent-laden polymeric fibers having average fiber diameters of less than about 1 micrometer, and transporting the nonwoven web through at least one infrared solvent stripping station wherein infrared radiation irradiates the nonwoven web in the absence of a solvent stripping fluid impinging on the nonwoven web in order to reduce the solvent concentration of the fibers to less than about 10,000 ppmw.

Abstract: A bag filter having a support structure clothed in a filter bag. The cloth of the filter bag is a composite of at least one substrate layer and at least one nanoweb bonded thereto in a face-to-face relationship. The nanoweb is positioned at the surface of the filter bag first exposed to the hot particle laden gas stream and can have a basis weight of greater than about 0.1 gsm.

Abstract: A composite fabric formed by depositing a web of nanofibers electroblown from a first polymer onto a first support web comprising fibers of larger average diameter than the nanofibers spun from a compatible material, in the absence of an adhesive between the webs, and solvent-bonding the webs together.

Abstract: A composite fabric formed by depositing a web of nanofibers electroblown from a first polymer onto a first support web comprising fibers of larger average diameter than the nanofibers spun from a compatible material, in the absence of an adhesive between the webs, and solvent-bonding the webs together.

Abstract: A composite fabric formed by depositing a web of nanofibers electroblown from a first polymer onto a first support web comprising fibers of larger average diameter than the nanofibers spun from a compatible material, in the absence of an adhesive between the webs, and solvent-bonding the webs together.

Abstract: A process for stripping chemically bonded spinning solvent from a solution-spun nonwoven web comprising the steps of providing a nonwoven web comprising solvent-laden polymeric fibers having average fiber diameters of less than about 1 micrometer, and transporting the nonwoven web through at least one infrared solvent stripping station wherein infrared radiation irradiates the nonwoven web in the absence of a solvent stripping fluid impinging on the nonwoven web in order to reduce the solvent concentration of the fibers to less than about 10,000 ppmw.

Abstract: A bag filter having a support structure clothed in a filter bag. The cloth of the filter bag is a composite of at least one substrate layer and at least one nanoweb bonded thereto in a face-to-face relationship. The nanoweb is positioned at the surface of the filter bag first exposed to the hot particle laden gas stream and can have a basis weight of greater than about 0.1 gsm.

Abstract: Filtration media are disclosed for use in high efficiency air filters for filtering particulate matter in air. The media make use of at least one layer of fibers having a diameter less than 1000 nanometers sandwiched between two scrim layers to achieve high efficiency particulate air (HEPA) filtration performance at relatively low pressure drops.