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

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.

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, and   a core-to-sheath area ratio of an area of the core to an area of the sheath is 2:8 to 7:3, 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.   
     
     
         2 . The core-sheath conjugate fiber for artificial hair according to  claim 1 ,
 wherein the fiber cross-section has a flat multilobed shape.   
     
     
         3 . The core-sheath conjugate fiber for artificial hair according to  claim 1 ,
 wherein the core cross-section has an elliptical or flat multilobed shape.   
     
     
         4 . The core-sheath conjugate fiber for artificial hair according to  claim 1 ,
 wherein a length of the 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 the major axis of the 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,
   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 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.   
     
     
         7 . The core-sheath conjugate fiber for artificial hair according to  claim 1 ,
 wherein the polyamide-based resin composition comprises a polyamide-based resin comprising at least 80 mol % or more of one selected from the group consisting of nylon 6 and nylon 66.   
     
     
         8 . A hair ornament comprising
 the core-sheath conjugate fiber for artificial hair according to  claim 1 .   
     
     
         9 . The hair ornament according to  claim 8 ,
 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.   
     
     
         10 . 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 nozzle,   wherein both a fiber cross-section and a core cross-section of the core-sheath conjugate fiber for artificial hair 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.   
     
     
         11 . The hair ornament according to  claim 8 ,
 wherein the fiber cross-section has a flat multilobed shape.   
     
     
         12 . The hair ornament according to  claim 8 ,
 wherein the core cross-section has an elliptical or flat multilobed shape.   
     
     
         13 . The hair ornament according to  claim 8 ,
 wherein a length of the 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).
 
   
     
     
         14 . The hair ornament according to  claim 8 ,
 wherein a length of the major axis of the 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,
   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).
 
   
     
     
         15 . The hair ornament according to  claim 8 ,
 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.   
     
     
         16 . The hair ornament according to  claim 8 ,
 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.