Fibers and methods of forming the fibers are described herein. The fibers generally include an ethylene based polymer exhibiting a molecular weight distribution of from about 2 to about 8.

Fibers and methods of forming the fibers are described herein. The fibers generally include an ethylene based polymer exhibiting a molecular weight distribution of from about 2 to about 8.

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.

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.

Compositions and methods for forming composites of polymer fibers, yarns, and textiles having enhanced elastocaloric and twistocaloric performance are provided herein. The composites can permit reversible temperature shifts within the materials, and can be used, for example, in energy conversion and thermal storage systems. These composites can be formulated by melt spinning the polymer fibers and using combinations of twisting and stretching of the polymer fibers. The fibers can include, for example, a base polymer that can be amorphous, or substantially amorphous, and desired alignment can occur, for example, by performing one or more of the various provided for techniques. In at least some embodiments, the composite materials can be further enhanced by including one or more phase change materials (PCMs), such as by cross-linking the one or more PCMs with one or more polymers and/or directly attaching the PCM(s) to the polymer(s).

Compositions and methods for forming composites of polymer fibers, yarns, and textiles having enhanced elastocaloric and twistocaloric performance are provided herein. The composites can permit reversible temperature shifts within the materials, and can be used, for example, in energy conversion and thermal storage systems. These composites can be formulated by melt spinning the polymer fibers and using combinations of twisting and stretching of the polymer fibers. The fibers can include, for example, a base polymer that can be amorphous, or substantially amorphous, and desired alignment can occur, for example, by performing one or more of the various provided for techniques. In at least some embodiments, the composite materials can be further enhanced by including one or more phase change materials (PCMs), such as by cross-linking the one or more PCMs with one or more polymers and/or directly attaching the PCM(s) to the polymer(s).

This disclosure provides a manufacturing method of a photochromic thermal insulation fiber, which includes preparing a photochromic masterbatch by including mixing 5 parts by weight of a photochromic dye and 95 parts by weight of polypropylene, preparing a near-infrared reflecting masterbatch by including mixing 15 parts by weight of a near-infrared reflecting dye and 85 parts by weight of nylon, preparing a first mixture by including mixing 10 parts by weight of the photochromic masterbatch and 75 parts by weight to 115 parts by weight of polypropylene, preparing a second mixture by including mixing 10 parts by weight of the near-infrared reflecting masterbatch and 65 parts by weight to 140 parts by weight of nylon, and performing a core-sheath melt spinning process with the first mixture and the second mixture to form a core layer and a sheath layer of the photochromic thermal insulation fiber.

This disclosure provides a manufacturing method of a photochromic thermal insulation fiber, which includes preparing a photochromic masterbatch by including mixing 5 parts by weight of a photochromic dye and 95 parts by weight of polypropylene, preparing a near-infrared reflecting masterbatch by including mixing 15 parts by weight of a near-infrared reflecting dye and 85 parts by weight of nylon, preparing a first mixture by including mixing 10 parts by weight of the photochromic masterbatch and 75 parts by weight to 115 parts by weight of polypropylene, preparing a second mixture by including mixing 10 parts by weight of the near-infrared reflecting masterbatch and 65 parts by weight to 140 parts by weight of nylon, and performing a core-sheath melt spinning process with the first mixture and the second mixture to form a core layer and a sheath layer of the photochromic thermal insulation fiber.

A monofilament of a polyethylene terephthalate bulked continuous filament (BCF) has elongation of 5% or more at an initial stress of 1.0 g/d, elongation of 25 to 35% at a medium-term stress of 3.0 g/d, tensile strength of 0.0 to 6.0 g/d, and elongation of 40 to 60%.

A monofilament of a polyethylene terephthalate bulked continuous filament (BCF) has elongation of 5% or more at an initial stress of 1.0 g/d, elongation of 25 to 35% at a medium-term stress of 3.0 g/d, tensile strength of 0.0 to 6.0 g/d, and elongation of 40 to 60%.