A coextrusion head for manufacturing a bicomponent polymer fiber, comprising a first inlet for receiving a core polymer component, a second inlet for receiving a cladding polymer component, and a dual-channel nozzle comprising an inner channel and an outer channel encompassing the inner channel. The inner and outer channel are in hydraulic connection with the first and second inlet, respectively. The dual-channel nozzle further comprises a joining path establishing a hydraulic connection between the inner channel, the outer channel, and a nozzle outlet of the dual-channel nozzle. The joining path is adapted for bringing the core polymer component and the cladding polymer component into contact with each other such that a contact layer comprising a mixture of the core polymer component and the cladding polymer component is formed between the core polymer component and the cladding polymer component.

A non-woven fiber article for use in a food, medical, or pharmaceutical production environment including a melt-spun polymer fiber is provided having a cross-section and a length and a detectable particulate present in an amount of 20 to 80 weight percent loadings of metal or 10 to 80 weight percent loadings of radiopaque particles to render the polymer fiber detectable by magnetic or X-ray detection, alone or in combination with a secondary functional particulate distributed with the polymer fiber to render the polymer fiber chemically responsive to a chemical reactant, change in pH or temperature. The detectable particulate and the secondary functional particulate are each independently present in a core, a sheath, or both portions of polymer matrix. A process of detecting a fabric made from such a fiber. The fabric article passes through detector. A signal is collected from the detector indicative of the presence of the fabric article.

A core-sheath conjugate fiber for artificial hair includes a core part and a sheath part. The core-sheath conjugate fiber for artificial hair is a colored fiber. The core part has a lightness L* of 10 or less in the CIE1976 color space and the sheath part has a lightness L* of 15 or more in the CIE1976 color space. With this configuration, the core-sheath conjugate fiber for artificial hair that has deep and natural colors similar to those of human hair and a good appearance, a hair ornament product including the same, and a method for producing the same are provided.

Provided are staple fibers for air laid capable of improving dispersibility, and a method for producing the same. The staple fibers for air laid are characterized by including stable fibers to which a fiber treatment agent containing a hydrophilic oil agent and a silicone-containing oil agent is adhered in an amount of 0.7 to 2 wt % of a weight of the staple fibers, wherein a weight ratio of the hydrophilic oil agent and the silicone-containing oil agent contained in the fiber treatment agent (a weight of the hydrophilic oil agent/a weight of the silicone-containing oil agent) is within a range of 60/40 to 90/10, and a moisture content is 2 to 13%.

Provided are staple fibers for air laid capable of improving dispersibility, and a method for producing the same. The staple fibers for air laid are characterized by including stable fibers to which a fiber treatment agent containing a hydrophilic oil agent and a silicone-containing oil agent is adhered in an amount of 0.7 to 2 wt % of a weight of the staple fibers, wherein a weight ratio of the hydrophilic oil agent and the silicone-containing oil agent contained in the fiber treatment agent (a weight of the hydrophilic oil agent/a weight of the silicone-containing oil agent) is within a range of 60/40 to 90/10, and a moisture content is 2 to 13%.

The present disclosure provides a photochromic thermal insulation fiber including a core layer and a sheath layer covering the core layer. The core layer includes about 99 parts by weight to 100 parts by weight of polypropylene and about 0.4 parts by weight to 0.6 parts by weight of a photochromic dye. The sheath layer includes about 98 parts by weight to 99 parts by weight of nylon and about 1 part by weight to 2 parts by weight of a near-infrared reflecting dye.

A polylactic acid fiber is provided. The polylactic acid fiber includes a first polylactic acid material and a second polylactic acid material. The first polylactic acid material is encapsulated by the second polylactic acid material. Based on a total volume of the polylactic acid fiber being 100%, a volume of the second polylactic acid material is at least 20%. The second polylactic acid material includes 15 wt % to 85 wt % of poly(D-lactic acid) and 15 wt % to 85 wt % of poly(L-lactic acid).

A polylactic acid fiber is provided. The polylactic acid fiber includes a first polylactic acid material and a second polylactic acid material. The first polylactic acid material is encapsulated by the second polylactic acid material. Based on a total volume of the polylactic acid fiber being 100%, a volume of the second polylactic acid material is at least 20%. The second polylactic acid material includes 15 wt % to 85 wt % of poly(D-lactic acid) and 15 wt % to 85 wt % of poly(L-lactic acid).

A thermoplastic core-sheath fiber comprises: a polymer fiber core having a coextensive sheath layer disposed thereon, and an electrostatic charge enhancing additive. The sheath layer may comprise poly(4-methyl-1-pentene) and the fiber core and the sheath layer have different compositions. At least one of the fiber core or the sheath layer comprises an electret charge. A nonwoven fibrous web comprising the core-sheath fibers and a respirator including the nonwoven fibrous web are also disclosed.

A thermoplastic core-sheath fiber comprises: a polymer fiber core having a coextensive sheath layer disposed thereon, and an electrostatic charge enhancing additive. The sheath layer may comprise poly(4-methyl-1-pentene) and the fiber core and the sheath layer have different compositions. At least one of the fiber core or the sheath layer comprises an electret charge. A nonwoven fibrous web comprising the core-sheath fibers and a respirator including the nonwoven fibrous web are also disclosed.