Abstract: One or more embodiments of the present invention relate to a core-sheath conjugate fiber for artificial hair including a core and a sheath. The core is composed of a polyester-based resin composition containing a polyester-based resin as a main component, and the sheath is composed of a polyamide-based resin composition containing a polyamide-based resin as a main component. A core-to-sheath area ratio of the core to the sheath is 2:8 to 7:3, and both a fiber cross-section and a core cross-section have a flat shape, a major axis of the core cross-section is in a direction that substantially coincides with a direction of a major axis of the fiber cross-section, and an eccentricity ratio of the fiber in a minor axis direction is 5% or more. As a result, fibers for artificial hair having a texture and an appearance that are similar to those of human hair and having favorable curl setting properties are provided.

Abstract: One or more embodiments of the present invention relate to a core-sheath conjugate fiber for artificial hair that includes a core and a sheath. The core is composed of a polyester-based resin composition containing a polyester-based resin as a main component, and the sheath is composed of a polyamide-based resin composition containing a polyamide-based resin as a main component. The polyester-based resin composition and the polyamide-based resin composition contain a bromine-based flame retardant. In the core-sheath conjugate fiber for artificial hair, a core-to-sheath area ratio of the core to the sheath is 2:8 to 8:2. A fiber cross-section of the core-sheath conjugate fiber for artificial hair has a flat multilobed shape, and the fiber cross-section includes a hollow portion. A ratio of an area of the hollow portion to a total area of the fiber cross-section is 5% or more and 30% or less. The hollow portion has a polygonal shape.

Abstract: A core-sheath conjugate fiber for artificial hair including a core part and a sheath part is provided. The core part includes of a polyester-based resin composition that contains a polyester-based resin as a main component and the sheath part includes a polyamide-based resin composition that contains a polyamide-based resin as a main component. The core-sheath conjugate fiber for artificial hair has a core-to-sheath area ratio of core:sheath=2:8 to 8:2 and a flat two-lobed cross sectional shape, and the polyamide-based resin composition has a melt viscosity of 140 Pa·s or less and contains a pigment. With this configuration, a core-sheath conjugate fiber for artificial hair in which exposure of the core part is suppressed and that has a touch close to that of human hair and an improved combing property, a hair ornament product including the same, and a method for producing the same are provided.

Abstract: A core-sheath conjugate fiber for artificial hair includes a core part and a sheath part. The core-sheath conjugate fiber for artificial hair has a flat two-lobed cross sectional shape or an elliptical cross sectional shape, and has a core-to-sheath area ratio of core:sheath=3:7 to 8:2 in a fiber cross section. The sheath part contains a polyamide-based resin composition containing a polyamide-based resin. The core part has a modified flat two-lobed cross sectional shape or a modified elliptical cross sectional shape including a pair of protrusions protruding from the center side toward the outer circumferential side along a minor axis direction of the fiber cross section. A core-sheath conjugate fiber for artificial hair having a touch close to that of human hair, an excellent combing property, and a good curl setting property, a hair ornament product including the same, and a method for producing the same are provided.

Abstract: The present disclosure relates to a core-sheath conjugate fiber for artificial hair including a core part and a sheath part. The core-sheath conjugate fiber for artificial hair has a flat multilobed cross sectional shape, and has a core-to-sheath area ratio of 2:8 to 9:1, and a viscosity ratio a/b between a melt viscosity a of a core part resin composition and a melt viscosity b of a sheath part resin composition is 2.0 or more and 7.0 or less. The present disclosure provides a core-sheath conjugate fiber for artificial hair having a touch close to that of human hair, excellent peel resistance at room temperature, and good combing property, a hair ornament product including the core sheath conjugate fiber, and a production method.

Abstract: The present disclosure relates to a core-sheath conjugate fiber for artificial hair including a core part and a sheath part, wherein the core-sheath conjugate fiber for artificial hair is a colored fiber, a color difference between the core-sheath conjugate fiber for artificial hair and the core part is 3.0 or more, and a color difference between the core-sheath conjugate fiber for artificial hair and the sheath part is also 3.0 or more. Provided are a core-sheath conjugate fiber for artificial hair capable of realizing deep colors and having a good appearance close to that of human hair, a hair ornament product including the core-sheath conjugate fiber, and a production method.

Abstract: A conjugate fiber including a core part and a sheath part covering the core part such that the conjugate fiber has a core-to-sheath area ratio of core:sheath=2:8 to 7:3 and an eccentricity of 5% or more in a cross section thereof. The cross section is in a multilobed shape and has a major axis of length L and a first minor axis of length Si y satisfying a ratio of L/S1 being 1.10-3.00. The core part has a major axis of length Lc and a first minor axis of length Sc satisfying a ratio of Lc/Sc being 1.10-3.00. The major axis of the core part is in a direction that substantially coincides with a direction of the major axis of the cross section.

Abstract: A method for producing a stretched film comprising a first step of stretching a long film by increasing a holding distance in the width direction and a second step of shrinking by decreasing the holding distance in the width direction. One side edge of the long film has a traveling direction with at least three bending travels, while the other side edge has a traveling direction with at least two bending travels. The first step or the second step performs the bending travel at one or both of the side edges. The first step or the second step has a traveling trajectory in which the both side edges of the long film travel to the same side. The method achieves suppression of wrinkles formed on the stretched film, limitation of biaxiality of the stretched film, and provides a stretched film having optical properties suitably usable as a retardation plate.

Abstract: The present invention aims at providing a method for producing a stretched film, the method achieving suppression of wrinkles formed on the stretched film and limitation of biaxiality of the stretched film within a desired range and being carried out with simple facilities and providing a stretched film having optical properties suitably usable as a retardation plate. A first step of stretching a long film by increasing a holding distance in the width direction and a second step of shrinking the long film having been stretched in the first step by decreasing the holding distance in the width direction are performed. One side edge in the width direction of the long film travels with at least three bending travels, while the other side edge paired with the one side edge travels with at least two bending travels. Further, the first step or the second step performs the bending travel at one or both of the side edges in the width direction of the long film.