A nanofiber nonwoven product is disclosed which comprises a polyamide with a relative viscosity from 2 to 330, spun into nanofibers with an average diameter of less than 1000 nanometers (1 micron). In general, the inventive products are prepared by: (a) providing a polyamide composition, wherein the polyamide has a relative viscosity from 2 to 330; (b) melt spinning the polyamide composition into a plurality of nanofibers having an average fiber diameter of less than 1 micron, followed by (c) forming the nanofibers into the product.

A fiber assembly according to one embodiment of the present disclosure includes a fiber. The fiber includes a core part that contains a coloring compound, a photothermal conversion material, and a color developer/reducer, and a sheath part that covers the core part and has a heat-insulating property.

A nanofiber for a filter medium is provided that includes fiber-forming ingredients including polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) and an emulsifying agent for improving the miscibility of the fiber-forming ingredients. The nanofiber has excellent mechanical strength and chemical resistance and, at the same time, significantly increased hydrophilicity without a separate surface modification/treatment to/on the nanofiber. A filter medium comprising said nanofiber can exhibit improved flux and filtration efficiency and excellent physical properties in a water treatment process in which a pressure equal to or more than a predetermined level is applied and which requires the filter medium to have high mechanical strength and in a water treatment process which requires chemical resistance as the liquid being filtered is strongly acidic or alkaline. Further, since the nanofiber has significantly superior spinnability, the mass productivity of the filter medium is significantly improved, and the unit costs of production can be reduced.

A sheet is produced by (i) producing a sheet by entangling woven or knitted material including a thread composed of a composite fiber such that two kinds or more of polyethylene terephthalate polymers different in intrinsic viscosity are stuck together in a side-by-side type along the fiber length direction and/or of a core-in-sheath type composite fiber such that two kinds or more of polyethylene terephthalate polymers different in intrinsic viscosity form an eccentric core-in-sheath structure, with a fiber capable of converting into ultra fine fibers composed of two kinds or more of polymeric substances different in solubility in solvent, (ii) developing an ultra fine fiber with an average single fiber fineness of 0.001 dtex or more and 0.5 dtex or less by treating the sheet with a solvent to thereafter provide elastomer having polyurethane as a main component by impregnating and solidifying solvent solution of elastomer having polyurethane as a main component into the sheet, or of providing elastomer having polyurethane as a main component by impregnating and solidifying solvent solution of elastomer having polyurethane as a main component into the sheet to thereafter develop an ultra fine fiber with an average single fiber fineness of 0.001 dtex or more and 0.5 dtex or less by treating the sheet with a solvent, and (iii) rubbing and shrinking the woven or knitted material under the condition of 110 C. or more.

A smokeless tobacco product includes smokeless tobacco and structural fibers. The structural fibers forming a network in which the smokeless tobacco is entangled. The structural fibers have a composition different from the smokeless tobacco. The tobacco-entangled fabric can have an overall oven volatiles content of at least 10 weight percent. In some embodiments, the structural fibers form a nonwoven network. In some embodiments, fibrous structures of the smokeless tobacco are entangled with the structural fibers.

A medical device in the form of a nonwoven wound dressing includes rotospun fibers including at least one synthetic and bioabsorbable polymer and at least one hydrophilic and/or tissue-adhesive polymer, and a method of producing the medical device including using rotospinning to produce fibers from a fiber raw material including at least one synthetic and bioabsorbable polymer and at least one hydrophilic and/or tissue-adhesive polymer.

A masterbatch is disclosed, along with associated methods, and biodegradable filaments, fibers, yarns and fabrics. The masterbatch includes 0.2 to 5 mass % CaCO.sub.3, an aliphatic polyester with a repeat unit having from two to six carbons in the chain between ester groups, with the proviso that the 2 to 6 carbons in the chain do not include side chain carbons, and a carrier polymer selected from the group consisting of PET, nylon, other thermoplastic polymers, and combinations thereof.

A melt blowing system for the manufacturing of pleatable/moldable nonwoven fabrics includes a collector positioned to receive a plurality of fibers, a first die in fluid communication with a first liquid polymer supply having a melt flow index of about 500 or lower, and a second die in fluid communication with a second liquid polymer supply having a melt flow index of about 500 or higher. The first die has a concentric air design, includes a plurality of spinneret nozzles facing the collector surface, and is configured to draw a first plurality of fibers. The second die includes a plurality of spinneret nozzles having smaller capillary diameter than those of the first die and is positioned to draw a second plurality of fibers such that the first and second pluralities of fibers form a co-mingled nonwoven web with varying fiber diameters on the collector surface.

Membranes suitable for use in membrane distillation are provided. Such membranes may include nano-fibrous layers with adjustable pore sizes. The membranes may include a hydrophobic nano fibrous scaffold and a thin hydrophilic protecting layer that can significantly reduce fouling and scaling problems.

A multi-component fiber including at least first and second components. In some cases, at least a portion of the first component is opaque and microporous, and the second component is different from the first component. In some cases, at least a portion of the second component can be seen through at least a portion of the first component. A fiber having an opaque, microporous region and a see-through region of lower porosity is also disclosed. Fibrous webs including such fibers are also disclosed. In some cases, the fibrous web has at least one first region where first portions of the multiple fibers are opaque and microporous and at least one second region where second portions of the multiple fibers form a see-through region of lower porosity. Articles and laminates including the fibrous webs are disclosed. Methods of making the fibers, fibrous webs, and articles are also disclosed.