Core-sheath conjugate fiber for artificial hair, hair ornament including same, and method for producing same

Patent metadata

Field	Value
Publication number	US-12522952-B2
Application number	US-202118253723-A
Country	US
Kind code	B2
Filing date	Oct 20, 2021
Priority date	Dec 28, 2020
Publication date	Jan 13, 2026
Grant date	Jan 13, 2026

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. As a result, fibers for artificial hair that have a texture similar to that of human hair, high durability, favorable curl setting properties, and high flame resistance are provided.

First claim

The invention claimed is:

1 . A core-sheath conjugate fiber for artificial hair comprising:
a core; and a sheath, wherein the core comprises a polyester-based resin composition comprising a polyester-based resin, and the sheath comprises a polyamide-based resin composition comprising a polyamide-based resin, the polyester-based resin composition and the polyamide-based resin composition comprise a bromine-based flame retardant, a core-to-sheath area ratio of an area of the core to an area of the sheath of the core-sheath conjugate fiber for artificial hair is 2:8 to 8:2, a fiber cross-section of the core-sheath conjugate fiber for artificial hair has a flat multilobed shape, 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, and the hollow portion has a polygonal shape, and the core-sheath conjugate fiber for artificial hair has a concentric structure in which center positions of the core and the hollow portion match a center position of the fiber.

2 . The core-sheath conjugate fiber for artificial hair according to claim 1 ,
wherein the fiber cross-section has a flat bilobed shape.

3 . The core-sheath conjugate fiber for artificial hair according to claim 1 ,
wherein a core cross-section of the core-sheath conjugate fiber for artificial hair has a flat bilobed shape.

4 . The core-sheath conjugate fiber for artificial hair according to claim 1 ,
wherein a length of a major axis of the fiber cross-section and a length of a first minor axis of the fiber cross-section satisfy the equation (1) below, where the major axis of the fiber cross-section is a longest straight line among an axisymmetric axis and straight lines connecting any two points on the outer circumference of the fiber cross-section so as to be parallel to the axisymmetric axis, and the first minor axis of the fiber cross-section is a longest straight line formed when any two points on the outer circumference of the fiber cross-section are connected perpendicularly to the major axis of the fiber cross-section, the length of the major axis of the fiber cross-section/the length of the first minor axis of the fiber cross-section=1.1 or more and 2.0 or less (1).

5 . The core-sheath conjugate fiber for artificial hair according to claim 1 ,
wherein a length of a major axis of a core cross-section and a length of a first minor axis of the core cross-section satisfy the equation (2) below, where the major axis of the core cross-section is a longest straight line among an axisymmetric axis and straight lines connecting any two points on the outer circumference of the core cross-section so as to be parallel to the axisymmetric axis, and the first minor axis of the core cross-section is a longest straight line formed when any two points on the outer circumference of the core cross-section are connected perpendicularly to the major axis of the core cross-section, satisfy the equation (2) below, the length of the major axis of the core cross-section/the length of the first minor axis of the core cross-section=1.3 or more and 2.0 or less (2).

6 . The core-sheath conjugate fiber for artificial hair according to claim 1 ,
wherein the hollow portion has a polygonal shape having a first side with an angle of 80 degrees or more and 100 degrees or less with respect to a major axis of the fiber cross-section, and a second side with an angle of 80 degrees or more and 100 degrees or less with respect to the major axis of the fiber cross-section.

7 . The core-sheath conjugate fiber for artificial hair according to claim 6 ,
wherein an angle between the first side and the second side is in a range of 0 degrees or more and 40 degrees or less.

8 . The core-sheath conjugate fiber for artificial hair according to claim 6 ,
wherein both of the first side and the second side of the hollow portion have a length of 10 μm or more and 30 μm or less.

9 . The core-sheath conjugate fiber for artificial hair according to claim 1 ,
wherein the hollow portion has at least one polygonal shape selected from the group consisting of a quadrangular shape, a pentagonal shape, a hexagonal shape, a heptagonal shape, and an octagonal shape.

10 . The core-sheath conjugate fiber for artificial hair according to claim 1 ,
wherein the polyester-based resin composition comprises at least one polyester-based resin selected from the group consisting of polyalkylene terephthalate and a copolyester comprising 80 mol % or more of polyalkylene terephthalate.

11 . The core-sheath conjugate fiber for artificial hair according to claim 1 ,
wherein the polyamide-based resin composition comprises a polyamide-based resin comprising 80 mol % or more of at least one selected from the group consisting of nylon 6 and nylon 66.

12 . A hair ornament comprising
the core-sheath conjugate fiber for artificial hair according to claim 1 .

13 . The hair ornament according to claim 12 ,
wherein the hair ornament is at least one selected from the group consisting of a hair wig, a hairpiece, weaving hair, a hair extension, braided hair, a hair accessory, and doll hair.

14 . The hair ornament according to claim 12 ,
wherein the hollow portion has a polygonal shape having a first side with an angle of 80 degrees or more and 100 degrees or less with respect to a major axis of the fiber cross-section, and a second side with an angle of 80 degrees or more and 100 degrees or less with respect to the major axis of the fiber cross-section.

15 . The hair ornament according to claim 14 ,
wherein an angle between the first side and the second side is in a range of 0 degrees or more and 40 degrees or less.

16 . The hair ornament according to claim 14 ,
wherein the hollow portion has at least one polygonal shape selected from the group consisting of a quadrangular shape, a pentagonal shape, a hexagonal shape, a heptagonal shape, and an octagonal shape.

17 . The hair ornament according to claim 14 ,
wherein both of the first side and the second side of the hollow portion have a length of 10 μm or more and 30 μm or less.

18 . A method for producing the core-sheath conjugate fiber for artificial hair according to claim 1 , comprising:
melt spinning a polyester-based resin composition and a polyamide-based resin composition, using a core-sheath conjugate spinning nozzle, wherein a hollow portion having a polygonal shape is formed in a fiber cross-section, and a ratio of the area of the hollow portion to the total area of the fiber cross-section is 5% or more and 30% or less.

Assignees

• Kaneka Corp

Inventors

• Yasutomo Norikazu

Classifications

• D10B2503/08

  Wigs · CPC title

• D10B2401/04

  Heat-responsive characteristics · CPC title

• D10B2331/04

  polyesters, e.g. polyethylene terephthalate [PET] · CPC title

• D10B2331/02

  polyamides (D10B2331/08 takes precedence) · CPC title

• D01F8/14

  with at least one polyester as constituent · CPC title