Core-sheath composite fiber for artificial hair, headgear product containing the same, and method for producing the same

Abstract

In one or more embodiments, the present invention relates to a core-sheath composite fiber for artificial hair, which is a core-sheath composite fiber for artificial hair comprising a core part and a sheath part. The core-sheath composite fiber for artificial hair is a colored fiber. The brightness L* of the core part in the CIE1976 color space is 10 or less, and the brightness L* of the sheath part in the CIE1976 color space is 15 or more. Thus, there are provided a core-sheath composite fiber for artificial hair that exhibits a deep and natural tone equivalent to that of human hair and has a good appearance, a headdress product containing the same, and a method for manufacturing the same.

Description

Technical Field

[0001] The present invention relates to a core-sheath composite fiber for artificial hair that can be used as a substitute for human hair, a headdress product containing the same, and a method for manufacturing the same. Background Art

[0002] In headdress products such as wigs, wig caps, accessory wigs, hair bands, and doll hair, human hair has been used in the past. However, in recent years, it has become difficult to obtain human hair, and the demand for artificial hair as a substitute for human hair has increased. As synthetic fibers used in artificial hair, acrylic fibers, vinyl chloride fibers, vinylidene chloride fibers, polyester fibers, polyamide fibers, polyolefin fibers, etc. can be cited. Among them, as an artificial hair fiber that can obtain a feel similar to human hair and has excellent durability and heat resistance, a core-sheath composite fiber having a polyester as a core component and a polyamide as a sheath component has been developed (Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication Gazette No. 2017 / 187843 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, since the artificial hair fiber described in Patent Document 1 has a single and uniform color tone, it is difficult to achieve a natural color tone with depth like that of human hair.

[0008] In order to solve the above problems, the present invention provides a core-sheath composite fiber for artificial hair that exhibits a natural color tone with depth equivalent to that of human hair and has a good appearance, a headdress product containing the same, and a method for manufacturing the same.

[0009] Means for Solving the Problems

[0010] In one or more embodiments, the present invention relates to a core-sheath composite fiber for artificial hair, which is a core-sheath composite fiber for artificial hair comprising a core portion and a sheath portion, the core-sheath composite fiber for artificial hair being a colored fiber, the brightness L* of the core portion in the CIE1976 color space being 10 or less, and the brightness L* of the sheath portion in the CIE1976 color space being 15 or more.

[0011] The present invention relates to a headdress product, characterized by comprising the above core-sheath composite fiber for artificial hair.

[0012] The present invention relates to a method for manufacturing a core-sheath composite fiber for artificial hair, characterized in that it is a method for manufacturing the core-sheath composite fiber for artificial hair, comprising a step of melt-spinning a core resin composition and a sheath resin composition using a core-sheath type composite nozzle, and a step of dyeing the core-sheath composite fiber for artificial hair, and at least the core resin composition contains a pigment.

[0013] Advantages of the Invention

[0014] According to the present invention, it is possible to provide a core-sheath composite fiber for artificial hair that exhibits a deep and natural hue equivalent to that of human hair and has a good appearance, and a headdress product containing the same.

[0015] Furthermore, according to the manufacturing method of the present invention, it is possible to obtain a core-sheath composite fiber for artificial hair that exhibits a deep and natural hue equivalent to that of human hair and has a good appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic view showing a fiber cross-section of a core-sheath composite fiber for artificial hair according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The inventors of the present invention repeatedly conducted in-depth research to solve the above problems, and as a result, found that: in a core-sheath composite fiber for artificial hair including a core part and a sheath part, by coloring the fiber, setting the luminance L* in the CIE1976 color space of the core part to 10 or less, and setting the luminance L* in the CIE1976 color space of the sheath part to 15 or more, it is possible to obtain a core-sheath composite fiber for artificial hair having a deep and natural hue and appearance equivalent to that of human hair, thereby achieving the present invention. Preferably, by including at least a pigment in the core part and dyeing the core part and the sheath part, it becomes easy to set the luminance L* in the CIE1976 color space of the core part to 10 or less, and set the luminance L* in the CIE1976 color space of the sheath part to 15 or more.

[0018] <Luminance>

[0019] The so-called luminance L* (hereinafter, also simply referred to as "L*") is used in the CIE1976 (L*, a*, b*) color space. The CIE1976 (L*, a*, b*) color space is widely used in the industry as a color space that is uniform in human perception and is measured by a general color difference meter. It should be noted that a* (a positive value indicates the red direction, and a negative value indicates the green direction) and b* (a positive value indicates the yellow direction, and a negative value indicates the blue direction) refer to chromaticity.

[0020] Since human hair has a complex structure including multiple layers such as the cuticle, cortex, and medulla, it is presumed that the reflected light exhibits various color tones, presenting a deep and complex appearance unique to human hair. On the other hand, in general core-sheath fibers for artificial hair, the core and the sheath are of the same color in order to simplify the manufacturing process, so the appearance is single and becomes uniform.

[0021] Therefore, in the core-sheath composite fiber for artificial hair (hereinafter, also simply referred to as "core-sheath composite fiber"), by coloring the core-sheath composite fiber for artificial hair and setting the brightness L* of the colored core to 10 or less and the brightness L* of the sheath to 15 or more, the core and the sheath exhibit different color tones, and a deep tone and a complex appearance derived from such a core-sheath structure can be expressed. Preferably, the brightness L* of the sheath is 24 or more. More preferably, the brightness L* of the core is 8 or less and the brightness L* of the sheath is 24 or more. In addition, in one or more embodiments, although not particularly limited, from the viewpoint that the dyed core-sheath composite fiber exhibits a deep and natural hue and appearance equivalent to that of human hair, the brightness L* of the core may also be 5 or more. In addition, in one or more embodiments, although not particularly limited, from the viewpoint that the dyed core-sheath composite fiber exhibits a deep and natural hue and appearance equivalent to that of human hair, the brightness L* of the sheath may also be 40 or less.

[0022] In addition, if the brightness L* value of the sheath is greater than the brightness L* value of the core, the light that passes through the sheath and is reflected on the surface of the core will not be attenuated in the sheath when it passes through the sheath again and reaches the surface, so in addition to the reflected light on the surface of the sheath, the reflected light from the surface of the core also affects the color tone, and it is easy to achieve a deep color tone. On the other hand, when the brightness L* value of the sheath is less than the brightness L* value of the core, since the light that passes through the sheath and is reflected on the surface of the core is attenuated in the sheath when it passes through the sheath again and reaches the surface, it is difficult to achieve a deep color tone. In addition, if the core and the sheath are set to a combination with the same color tone, it is not easy to set a large difference in the color tone between the core and the sheath, and it is difficult to achieve a deep color tone.

[0023] Specifically, for example, by setting a combination such as black and light camel color, a deep and complex appearance similar to that of human hair can be expressed. Preferably, by setting the core to a dark color and the sheath to a light color, compared with the case of setting the core to a light color and the sheath to a dark color or the case of setting the core to a dark color and the sheath to a dark color, a deep appearance can be obtained.

[0024] <Coloring method>

[0025] The core-sheath composite fiber for artificial hair can be colored by mass coloring and / or dyeing.

[0026] (Dope Dyeing)

[0027] In the core-sheath conjugate fiber for artificial hair, at least the core part is dope-dyed. In one or more embodiments of the present invention, dope dyeing means coloring by adding a pigment to a resin composition as a raw material. For example, by adding general pigments such as carbon black and anthraquinone-based pigments to the resin composition, a core-sheath fiber for artificial hair having a desired color can be obtained. In addition to using pigments, pigment masterbatches can also be used. A pigment masterbatch is a substance obtained by kneading a pigment and a resin composition using a kneader such as an extruder and pelletizing (sometimes referred to as blending). By previously dispersing a pigment, which is generally regarded as difficult to handle because it is in a fine powder form, into the resin composition, the operation can be made easier and uneven coloring of the obtained fiber can be suppressed.

[0028] Furthermore, in fibers for hair that require many colors, from the viewpoints of production simplicity and reduction of pigment inventory costs, it is preferable to obtain fibers that are dope-dyed to a desired color by using specific multiple pigment masterbatches and adjusting their addition ratios. In particular, by using three pigment masterbatches of black, red, and yellow and adjusting the blending ratio of the masterbatches, fibers having a desired color can be obtained. For example, when blending at 20% by weight of the pigment masterbatch with black:red:yellow = 60:25:15 (parts by weight %) and adding 3.0 parts by weight relative to 100 parts by weight of the base resin, a black core-sheath conjugate fiber for artificial hair can be obtained.

[0029] (Dyeing)

[0030] In the core-sheath composite fiber for artificial hair, the core part and / or the sheath part is dyed. In one or more embodiments of the present invention, the so-called dyeing refers to a method of obtaining a colored fiber by causing a dye to bind and adsorb to the fiber after forming (spinning). As a control for the fiber raw material, disperse dyes, acid dyes, basic dyes, etc. can be used, for example. When coloring is carried out by a dyeing method, it can be carried out by the same method as the dyeing method for dyeing synthetic fibers such as ordinary polyester fibers or polyamide fibers. From the viewpoint of dyeing at least the sheath part, it can also be carried out by the same method as the case of dyeing a fiber composed only of the sheath resin composition. It is preferable that either the core part or the sheath part is dyed. As the dye used in the post-dyeing method, dyes such as black, yellow, red, and brown can be arbitrarily used. In addition, two or more dyes can be mixed and used for color adjustment. As specific examples of the above dyes, disperse dyes of the benzene azo type (monoazo, diazo, etc.), heterocyclic azo type (thiazole azo, benzothiazole azo, thiophene azo, etc.), anthraquinone type, and condensation type (quinophthalone, styryl, coumarin, etc.) are preferably used. The dyeing is preferably carried out at a temperature of 90°C or higher and 150°C or lower, more preferably 100°C or higher and 140°C or lower. In addition, it is preferable to adjust the pH of the dyeing bath containing the dye to an appropriate value. In addition, in the post-dyeing method, a dyeing assistant can also be used together with the dye for the purpose of improving the fixing property and dispersibility. Examples of the dyeing assistant include a dispersant, a leveling agent, and an oligomer remover.

[0031] As the above dyeing assistant, specifically, a formaldehyde condensate of naphthalene sulfonic acid, a polyoxyalkylene alkyl aryl ether, a polyoxyalkylene alkyl ester, a polyoxyalkylene alkyl aryl ether sulfate salt, a polyoxyalkylene aryl ether sulfate salt, etc. can be used. The above dyeing assistant is preferably used in a range of 0.5 g / L or more and 2 g / L or less with respect to the dyeing bath.

[0032] In addition, as a pH adjuster, for example, a combination of acetic acid and sodium acetate, a combination of acetic acid and sodium pyrophosphate, a combination of sodium dihydrogen phosphate or an organic phosphorus compound and a polycarboxylic acid, etc. can be used. The above pH adjuster is preferably used in a range of 0.5 g / L or more and 2 g / L or less with respect to the dyeing bath.

[0033] The dye in the dyeing method is preferably exhausted by 0.1% by mass or more in the core-sheath composite fiber for artificial hair. In the core-sheath composite fiber for artificial hair, since there are many color variations from dark colors such as black hair to intermediate colors such as brown and red hair, and light colors such as blond and white (gray) hair, it is necessary to appropriately adjust the exhaustion amount of the dye according to the color. The exhaustion amount of the dye can be adjusted by the concentration of the dyeing bath, the dyeing temperature, and the dyeing time.

[0034] As pigments, dyes, dyeing assistants, etc. used in the core-sheath composite fiber for artificial hair, substances having weather resistance and flame retardancy are preferred.

[0035] The core-sheath composite fiber for artificial hair may also contain various additives such as heat-resistant agents, stabilizers, fluorescent agents, antioxidants, antistatic agents, etc. as needed. As the stabilizer, for example, stearyl acid phosphate can be used.

[0036] In the case of performing simultaneous coloring of the stock solution and dyeing, a coloring method that conforms to the resin characteristics of the core and the sheath, such as dyeing the fiber after pre-coloring the stock solution, coloring the core with the stock solution, and dyeing the sheath, can be used.

[0037] In the core-sheath composite fiber for artificial hair, from the viewpoint of easily controlling the brightness L* of the core part to 10 or less, it is preferred that at least the core part contains pigments, and it is more preferred to use three kinds of pigment masterbatches of black, red, and yellow as pigments and adjust the blending ratio of the masterbatches.

[0038] <Shape of the core-sheath composite fiber>

[0039] The core-sheath composite fiber for artificial hair includes a core part and a sheath part and has a core-sheath structure. The cross-sectional shapes of the core-sheath composite fiber for artificial hair and the core part are not particularly limited and may be circular or non-circular. As the non-circular shape, for example, it may have at least one shape selected from the group consisting of an oval shape, a flat multi-lobed shape, an intersecting circular shape, a cocoon shape, an egg-shaped gourd shape, a dog bone shape, and a strip shape. From the viewpoints of beauty characteristics such as gloss, feel, combability, and curl retention, it is preferred that the fiber cross-section and the core part have the same flat multi-lobed cross-sectional shape in which the long axis direction of the fiber cross-section is substantially the same as the long axis direction of the core part. In the case where the fiber and the core part have the same flat multi-lobed cross-section in which the long axis direction of the fiber cross-section is substantially the same as the long axis direction of the core cross-section, in the fiber cross-section, since the outer peripheral shape of the fiber cross-section and the outer peripheral shape of the core part are similar shapes, the thickness of the sheath becomes uniform, and as artificial hair, good touch and appearance can be maintained, and the exposure of the core part to the surface can be prevented. In addition, since the fiber and the core part have a flat multi-lobed cross-sectional shape, concave and convex parts exist at the core-sheath interface, whereby the stress generated at the core-sheath interface due to deformation such as bending can be dispersed, and thus the separation of the fiber caused by the peeling of the two components can be prevented. Furthermore, since the long axis directions of the fiber cross-section and the core cross-section are substantially the same, the anisotropy of the bending elastic modulus due to the second moment of the cross-section is also the same in the whole fiber and the core part, and the quality necessary for artificial hair such as feel and combability can be easily adjusted.

[0040] Figure 1It is a schematic diagram showing the cross-section of a core-sheath composite fiber for artificial hair. The core-sheath composite fiber 1 for artificial hair in this schematic diagram includes a core part 10 and a sheath part 20. The long axis direction of the fiber cross-section is the same as that of the core cross-section. The cross-sectional shapes of both the core-sheath composite fiber 1 for artificial hair and the core part 10 are circular, and the core part 10 and the core-sheath composite fiber 1 for artificial hair are arranged in a concentric circle shape.

[0041] The cross-sectional shapes of the above-mentioned fiber and core part, as well as the core-sheath ratio, can be controlled by using a nozzle hole with a shape close to the target cross-sectional shape.

[0042] The core-sheath ratio (the ratio of the core part to the sheath part) in the fiber cross-section of the core-sheath composite fiber for artificial hair is not particularly limited. However, from the viewpoints of expressing a complex appearance and spinning and cross-sectional stability, etc., the core:sheath is preferably in the range of 1:9 to 9:1 by area ratio, more preferably 2:8 to 8:2, and further preferably 3:7 to 7:3.

[0043] From the viewpoint of being suitable for artificial hair, the fiber fineness of the core-sheath composite fiber for artificial hair is preferably 10 dtex or more and 150 dtex or less, more preferably 30 dtex or more and 120 dtex or less, further preferably 40 dtex or more and 100 dtex or less, and particularly preferably 50 dtex or more and 90 dtex or less.

[0044] <Composition of the core-sheath composite fiber>

[0045] The composition of the core-sheath composite fiber for artificial hair is not particularly limited. For example, the core-sheath composite fiber for artificial hair can be composed of a thermoplastic resin composition such as an acrylonitrile-based resin composition, a vinyl chloride-based resin composition, a vinylidene chloride-based resin composition, a polyester-based resin composition, a polyamide-based resin composition, a polyolefin-based resin composition, etc. In addition, two or more of these resin compositions can be combined. Furthermore, from the viewpoint of flame retardancy, a flame retardant can also be used in combination. It is preferable to use a polyester-based resin composition containing a polyester-based resin and a bromine-based polymer flame retardant, a polyamide-based resin composition containing a polyamide-based resin and a bromine-based polymer flame retardant, etc. As a resin composition having flame retardancy, for example, a resin composition containing 100 parts by weight or more of one or more resins selected from the group consisting of alkylene glycol terephthalate, a copolyester having alkylene glycol terephthalate as a main body, and polyamide, and 5 parts by weight or more and 40 parts by weight or less of a bromine-based polymer flame retardant can be cited.

[0046] Among them, from the aspects of satisfying the heat resistance and fiber physical properties required for artificial hair fibers and being relatively easy to operate in various processing steps such as resin processing, spinning, stretching, and heat treatment, polyester-based resin compositions and polyamide-based resin compositions are preferred. From the aspect of safety, a structure in which a resin composition having flame retardancy is disposed in either or both of the core part and the sheath part is more preferred.

[0047] The polyalkylene terephthalate is not particularly limited, and examples thereof include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexanedimethylene terephthalate, and the like. The copolyester having the polyalkylene terephthalate as the main body is not particularly limited, and examples thereof include copolyesters having a polyalkylene terephthalate such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexanedimethylene terephthalate as the main body and containing other copolymer components. The "copolyester having the polyalkylene terephthalate as the main body" means a copolyester containing 80 mol% or more of the polyalkylene terephthalate.

[0048] Examples of other copolymer components include polycarboxylic acids such as isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, terephthalic acid, trimellitic acid, pyromellitic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, and their derivatives; dicarboxylic acids containing sulfonates such as sodium isophthalate-5-sulfonate and sodium dihydroxyethyl isophthalate-5-sulfonate and their derivatives; 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, diethylene glycol, polyethylene glycol, trimethylolpropane, pentaerythritol, 4-hydroxybenzoic acid, ε-caprolactone, ethylene glycol ether of bisphenol A, and the like.

[0049] From the aspects of stability and ease of operation, the copolyester is preferably produced by reacting a small amount of other copolymer components in the polyalkylene terephthalate as the main body. As the polyalkylene terephthalate, a polymer of terephthalic acid and / or its derivative (for example, dimethyl terephthalate) and an alkylene glycol can be used. The copolyester can also be produced by polymerizing a mixture containing a small amount of other copolymer components, that is, monomer or oligomer components, in a mixture of terephthalic acid and / or its derivative (for example, dimethyl terephthalate) and an alkylene glycol used in the polymerization of the polyalkylene terephthalate as the main body.

[0050] The copolyester only needs to polycondense the above other copolymer components on the main chain and / or side chain of the polyalkylene terephthalate as the main body, and there is no particular limitation on the copolymerization method and the like.

[0051] As a specific example of a copolyester having polyalkylene terephthalate as the main component, there can be mentioned polyesters such as those having polyethylene terephthalate as the main component and copolymerizing one compound selected from the group consisting of ethylene glycol ethers of bisphenol A, 1,4-cyclohexanedimethanol, isophthalic acid, and sodium 5-sulfoisophthalate dihydroxyethyl ester.

[0052] The polyalkylene terephthalate and the copolyester having polyalkylene terephthalate as the main component can be used alone or in combination of two or more. Among them, polyethylene terephthalate (hereinafter also referred to as "PET"); polypropylene terephthalate; polybutylene terephthalate (hereinafter also referred to as "PBT"); a polyester having polyethylene terephthalate as the main component and copolymerizing ethylene glycol ether of bisphenol A; a polyester having polyethylene terephthalate as the main component and copolymerizing 1,4-cyclohexanedimethanol; a polyester having polyethylene terephthalate as the main component and copolymerizing isophthalic acid; and a polyester having polyethylene terephthalate as the main component and copolymerizing sodium 5-sulfoisophthalate dihydroxyethyl ester are preferably used alone or in combination of two or more.

[0053] The polyamide-based resin refers to a nylon resin obtained by polymerizing one or more selected from the group consisting of lactams, aminocarboxylic acids, mixtures of dicarboxylic acids and diamines, mixtures of dicarboxylic acid derivatives and diamines, and salts of dicarboxylic acids and diamines.

[0054] As specific examples of the lactam, there is no particular limitation, and for example, β-propiolactam, 2-pyrrolidone, δ-valerolactam, ε-caprolactam, heptalactam, octalactam, undecalactam, and dodecalactam can be mentioned. Among them, ε-caprolactam, undecalactam, and dodecalactam are preferred, and ε-caprolactam is particularly preferred. These lactams can be used singly or as a mixture of two or more.

[0055] As specific examples of the aminocarboxylic acid, there is no particular limitation, and for example, 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, etc. can be mentioned. Among them, 6-aminohexanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid are preferred, and 6-aminohexanoic acid is particularly preferred. These aminocarboxylic acids can be used singly or as a mixture of two or more.

[0056] Specific examples of the dicarboxylic acids used in the mixture of a dicarboxylic acid and a diamine, the mixture of a dicarboxylic acid derivative and a diamine, or the salt of a dicarboxylic acid and a diamine are not particularly limited, and examples thereof include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, octadecanedioic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid. Among them, adipic acid, sebacic acid, dodecanedioic acid, terephthalic acid, and isophthalic acid are preferred, and adipic acid, terephthalic acid, and isophthalic acid are particularly preferred. These dicarboxylic acids may be used alone or as a mixture of two or more.

[0057] Specific examples of the diamines used in the mixture of a dicarboxylic acid and a diamine, the mixture of a dicarboxylic acid derivative and a diamine, or the salt of a dicarboxylic acid and a diamine are not particularly limited, and examples thereof include aliphatic diamines such as 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 2-methyl-1,5-diaminopentane (MDP), 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, 1,14-diaminotetradecane, 1,15-diaminopentadecane, 1,16-diaminohexadecane, 1,17-diaminoheptadecane, 1,18-diaminooctadecane, 1,19-diaminononadecane, 1,20-diaminoeicosane, alicyclic diamines such as cyclohexanediamine and bis-(4-aminocyclohexyl)methane, and aromatic diamines such as m-xylylenediamine and p-xylylenediamine. Among them, aliphatic diamines are particularly preferred, and hexamethylenediamine is particularly preferably used. These diamines may be used alone or as a mixture of two or more.

[0058] The polyamide resin is not particularly limited, and for example, nylon 6 (hereinafter also referred to as PA6), nylon 66 (hereinafter also referred to as PA66), nylon 11, nylon 12, nylon 6·10, nylon 6·12, semi-aromatic nylon containing nylon 6T and / or 6I units, and copolymers of these nylon resins are preferably used. Particularly preferably, nylon 6, nylon 66, and copolymers of nylon 6 and nylon 66 are used.

[0059] The polyamide resin can be produced, for example, by a polyamide resin polymerization method in which a polyamide resin raw material is heated in the presence or absence of a catalyst. Stirring may or may not be carried out during this polymerization, but in order to obtain a homogeneous product, stirring is preferably carried out. The polymerization temperature can be arbitrarily set according to the degree of polymerization of the target polymer, the reaction yield, and the reaction time, but a lower temperature is preferred considering the quality of the finally obtained polyamide resin. The reaction rate can also be arbitrarily set. There is no limitation on the pressure, but in order to efficiently extract volatile components out of the system, the inside of the system is preferably set to a reduced pressure.

[0060] The polyamide resin can also be end-capped with an end-capping agent such as a carboxylic acid compound and an amine compound as needed. When the end is capped with a monocarboxylic acid or a monoamine, the concentration of the terminal amino group or the terminal carboxyl group of the obtained nylon resin is lower than that in the case where the end-capping agent is not used. On the other hand, when the end is capped with a dicarboxylic acid or a diamine, the sum of the concentrations of the terminal amino group and the terminal carboxyl group does not change, but the ratio of the concentrations of the terminal amino group and the terminal carboxyl group changes.

[0061] Specific examples of the carboxylic acid compound are not particularly limited, and examples include aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, myristoleic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid, methylcyclohexanecarboxylic acid, aromatic monocarboxylic acids such as benzoic acid, toluic acid, ethylbenzoic acid, phenylacetic acid, aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, octadecanedioic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid.

[0062] As specific examples of the amine compound, there is no particular limitation, and for example, aliphatic monoamines such as butylamine, pentylamine, hexylamine, heptylamine, octylamine, 2-ethylhexylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, octadecylamine, nonadecylamine, eicosylamine, etc., alicyclic monoamines such as cyclohexylamine, methylcyclohexylamine, etc., aromatic monoamines such as benzylamine, β-phenylethylamine, etc., aliphatic diamines such as 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, 1,14-diaminotetradecane, 1,15-diaminopentadecane, 1,16-diaminohexadecane, 1,17-diaminoheptadecane, 1,18-diaminooctadecane, 1,19-diaminononadecane, 1,20-diaminoeicosane, etc., alicyclic diamines such as cyclohexanediamine, bis-(4-aminocyclohexyl)methane, etc., aromatic diamines such as benzenedimethyldiamine, etc.

[0063] There is no particular limitation on the terminal group concentration of the polyamide resin, but in cases where it is necessary to improve the dyeability in fiber applications or to design materials suitable for alloying in resin applications, etc., a relatively high terminal amino group concentration is preferred. In addition, in cases where it is desired to suppress coloring or gelation under long-term aging conditions, etc., on the contrary, a relatively low terminal amino group concentration is preferred. Furthermore, in cases where it is desired to suppress the regeneration of lactam during remelting, filament breakage during melt spinning caused by the generation of oligomers, mold fouling during continuous injection molding, and the generation of die lines during continuous extrusion of films, it is preferred that both the terminal carboxyl group concentration and the terminal amino group concentration are low. It is only necessary to adjust the terminal group concentration according to the applicable use, but both the terminal amino group concentration and the terminal carboxyl group concentration are preferably 1.0×10 -5 ~15.0×10 -5 eq / g, more preferably 2.0×10 -5 ~12.0×10 -5 eq / g, particularly preferably 3.0×10 -5 ~11.0×10 -5 eq / g.

[0064] In addition, as the method for adding the end-capping agent, a method of adding it simultaneously with raw materials such as caprolactam at the initial stage of polymerization, a method of adding it during the polymerization process, a method of adding it when passing the nylon resin in a molten state through a vertical stirring film evaporator, etc. can be adopted. The end-capping agent can be added directly or dissolved in a small amount of solvent and then added.

[0065] The intrinsic viscosity (sometimes referred to as the IV value) of the polyester resin and the polyamide resin is not particularly limited, preferably 0.3 or more and 1.2 or less, more preferably 0.4 or more and 1.0 or less. If the intrinsic viscosity is 0.3 or more, the mechanical strength of the obtained fibers will not decrease, and there is no concern about dripping during the combustion test. In addition, if the intrinsic viscosity is 1.2 or less, the molecular weight will not increase too much, the melt viscosity will not become too high, melt spinning will be easy, and the fineness will also be easily made uniform.

[0066] As the brominated polymer flame retardant, there is no particular limitation. However, for example, from the viewpoints of heat resistance and flame retardancy, brominated epoxy flame retardants are preferably used. As the brominated epoxy flame retardant, a brominated epoxy flame retardant having an epoxy group or tribromophenol at the molecular end can be used as a raw material. The structure after melt-kneading of the brominated epoxy flame retardant is not particularly limited. However, when the total number of the structural units shown in the following chemical formula (1) and the structural units in which at least a part of the following chemical formula (1) is changed is set to 100 mol%, preferably 80 mol% or more is the structural unit shown in the chemical formula (1). The structure of the brominated epoxy flame retardant may also change at the molecular end after melt-kneading. For example, the molecular end of the brominated epoxy flame retardant can be substituted with a hydroxyl group, a phosphoric acid group, a phosphonic acid group, etc. other than an epoxy group or tribromophenol, and the molecular end can also be bonded to the polyester component by an ester bond.

[0067] [Chemical formula 1]

[0068]

[0069] In addition, a part of the structure other than the molecular end of the brominated epoxy flame retardant may also change. For example, the secondary hydroxyl group of the brominated epoxy flame retardant may be bonded to an epoxy group to form a branched structure, and as long as the bromine content in the brominated epoxy flame retardant molecule does not change significantly, a part of the bromine in the chemical formula (1) may also be detached or added.

[0070] As the brominated epoxy flame retardant, for example, a polymer type brominated epoxy flame retardant as shown in the following chemical formula (2) is preferably used. In the following chemical formula (2), m is 1 to 1000. As the polymer type brominated epoxy flame retardant as shown in the following chemical formula (2), for example, commercially available products such as brominated epoxy flame retardants (trade name "SR-T2MP") manufactured by Sakamoto Pharmaceutical Co., Ltd. can also be used.

[0071] [Chemical formula 2]

[0072]

[0073] From the viewpoints of making the touch and appearance more similar to human hair and further improving the crimpability and crimp retention, the core-sheath composite fiber for artificial hair preferably has a core portion composed of a polyester resin composition containing at least one polyester resin selected from the group consisting of alkylene glycol terephthalate and copolyester having alkylene glycol terephthalate as a main component, specifically, a polyester resin composition containing the polyester resin as a main component resin, and more preferably has a sheath portion composed of a polyamide resin composition containing a polyamide resin having at least one selected from the group consisting of nylon 6 and nylon 66 as a main component, specifically, a polyamide resin composition containing the polyamide resin as a main component resin. In the core-sheath composite fiber for artificial hair, the "polyamide resin having at least one selected from the group consisting of nylon 6 and nylon 66 as a main component" means a polyamide resin containing 80 mol% or more of nylon 6 and / or nylon 66.

[0074] In the core-sheath composite fiber for artificial hair, the "main component resin" means the resin having the largest content among the resins contained in the resin composition. When the total of the resins in the resin composition is set to 100% by weight, it preferably contains more than 50% by weight of the main component resin, more preferably contains 70% by weight or more, further preferably contains 85% by weight or more, further preferably contains 90% by weight or more, further preferably contains 95% by weight or more, and further preferably consists of 100% by weight.

[0075] In the polyester resin composition constituting the core portion, other resins may be contained in addition to the polyester resin as the main component resin. When the total of the resins in the polyester resin composition is set to 100% by weight, it preferably contains more than 50% by weight of the polyester resin as the main component resin, more preferably contains 70% by weight or more, further preferably contains 85% by weight or more, further preferably contains 90% by weight or more, further preferably contains 95% by weight or more, and further preferably consists of 100% by weight. Examples of other resins include polyamide resins, vinyl chloride resins, modified acrylic resins, polycarbonate resins, polyolefin resins, polyphenylene sulfide resins, and the like. They may be used alone or in combination of two or more.

[0076] In the polyamide-based resin composition constituting the sheath portion, other resins may be included in addition to the polyamide-based resin as the main component resin. When the total amount of the resins in the polyamide-based resin composition is set to 100% by weight, it is preferably to include more than 50% by weight of the polyamide-based resin as the main component resin, more preferably 70% by weight or more, further preferably 85% by weight or more, further preferably 90% by weight or more, further more preferably 95% by weight or more, and further preferably composed of 100% by weight. As other resins, for example, polyester-based resins, vinyl chloride-based resins, modified acrylic-based resins, polycarbonate-based resins, polyolefin-based resins, polyphenylene sulfide-based resins, etc. can be cited. They can be used alone or in combination of two or more.

[0077] The core-sheath composite fiber for artificial hair may also contain various additives such as flame retardants other than brominated epoxy-based flame retardants, flame retardant aids, heat resistant agents, stabilizers, fluorescent agents, antioxidants, antistatic agents, etc. as needed.

[0078] As flame retardants other than brominated epoxy-based flame retardants, for example, phosphorus-containing flame retardants, bromine-containing flame retardants, etc. can be cited. As phosphorus-containing flame retardants, for example, phosphate ester amide compounds, organic cyclic phosphorus-based compounds, etc. can be cited. As the above-mentioned bromine-containing flame retardants, for example, pentabromotoluene, hexabromobenzene, decabromodiphenyl, decabromodiphenyl ether, bis(tribromophenoxy)ethane, tetrabromophthalic anhydride, ethylenebis(tetrabromophthalimide), ethylenebis(pentabromophenyl), octabromotrimethylphenyl indane, phosphate tris(tribromoneopentyl) ester and other bromine-containing phosphate esters; brominated polystyrenes; brominated benzyl acrylate esters; brominated phenoxy resins; brominated polycarbonate oligomers; tetrabromobisphenol A, tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tetrabromobisphenol A-bis(allyl ether), tetrabromobisphenol A-bis(hydroxyethyl ether) and other tetrabromobisphenol A derivatives; bromine-containing triazine-based compounds such as tris(tribromophenoxy)triazine; bromine-containing isocyanuric acid-based compounds such as tris(2,3-dibromopropyl) isocyanurate, etc. Among them, one or more selected from the group consisting of phosphate ester amide compounds, organic cyclic phosphorus-based compounds, and brominated phenoxy resin-based flame retardants are preferred in terms of excellent flame retardancy.

[0079] The brominated epoxy-based flame retardant is not particularly limited. For example, in the core resin composition and / or the sheath resin composition, it is preferably included in an amount of 5 parts by weight or more and 40 parts by weight or less based on 100 parts by weight of the main component resin.

[0080] As a flame retardant aid, for example, antimony compounds, composite metals containing antimony, etc. can be cited. As antimony compounds, for example, antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, potassium antimonate, calcium antimonate, etc. can be cited. From the viewpoints of flame retardancy improvement effect and influence on touch, one or more selected from the group consisting of antimony trioxide, antimony pentoxide, and sodium antimonate are more preferably selected.

[0081] The flame retardant aid is not particularly limited. For example, in the core resin composition and / or the sheath resin composition, it is preferably contained in an amount of 0.1 part by weight or more and 10 parts by weight or less based on 100 parts by weight of the main component resin.

[0082] From the viewpoints of adjusting gloss or feel, the core-sheath composite fiber for artificial hair can form a moderate uneven shape on the surface by chemical treatment or containing fine particles. As the fine particles, for example, calcium carbonate, silicon oxide, titanium oxide, aluminum oxide, zinc oxide, talc, kaolin, montmorillonite, bentonite, mica, composite particles having silicon oxide as the main body, etc. can be cited. They can be used alone or in combination of two or more.

[0083] <Manufacturing method of core-sheath composite fiber>

[0084] As a manufacturing method of the core-sheath composite fiber for artificial hair, the melt spinning method is preferably used. For example, in the case of a polyester-based resin composition, the temperatures of an extruder, a gear pump, a nozzle, etc. are set to 250°C or higher and 300°C or lower, melt spinning is performed, and after the spun filament passes through a heating cylinder, it is cooled to below the glass transition temperature of the polyester-based resin and drawn at a speed of 50 m / minute or higher and 5000 m / minute or lower, whereby a spun filament (undrawn filament) is obtained. In addition, in the case of a polyamide-based resin composition, the temperatures of an extruder, a gear pump, a nozzle, etc. are set to 260°C or higher and 320°C or lower, melt spinning is performed, and after the spun filament passes through a heating cylinder, it is cooled to below the glass transition temperature of the polyamide-based resin and drawn at a speed of 50 m / minute or higher and 5000 m / minute or lower, whereby a spun filament (undrawn filament) can be obtained. It should be noted that in melt spinning, the core resin composition is supplied by a core extruder, the sheath resin composition is supplied by a sheath extruder, and the molten polymer can be ejected using a core-sheath type composite spinning nozzle having a specified shape.

[0085] When the core-sheath composite fiber for artificial hair is composed of a thermoplastic resin composition such as a polyester-based resin composition, it is also possible to produce the core-sheath composite fiber for artificial hair by melt-kneading the thermoplastic resin composition using various general kneaders, granulating it, and then performing melt spinning using a core-sheath type composite spinning nozzle. The fineness can also be controlled by cooling the spun filament in a water tank equipped with cooling water. The temperature and length of the heating cylinder, the temperature and blowing volume of the cooling air, the temperature of the cooling water tank, the cooling time, and the drawing speed can be appropriately adjusted according to the discharge amount of the polymer and the number of holes in the nozzle.

[0086] Preferably, the core is colored by including at least a pigment in the core resin composition.

[0087] The spun filament (undrawn filament) is preferably heat-drawn. The drawing can be carried out by either a two-step method in which the spun filament is temporarily wound and then drawn, or a direct spinning drawing method in which the spun filament is continuously drawn without winding. The heat drawing can be carried out by a one-step drawing method or a multi-step drawing method of two or more steps.

[0088] As the heating mechanism in the heat drawing, a heating roll, a heating plate, a steam injection device, a warm water tank, etc. can be used, and they can also be used in combination as appropriate.

[0089] An oil agent such as a fiber treatment agent or a softening agent can also be imparted to the core-sheath composite fiber for artificial hair to make the touch and feel more similar to human hair. As the fiber treatment agent, for example, silicone-based fiber treatment agents, non-silicone-based fiber treatment agents, etc. for improving the touch and combability can be cited.

[0090] The core-sheath composite fiber for artificial hair is preferably dyed through a dyeing process.

[0091] The core-sheath composite fiber for artificial hair can also be processed by gear crimping. Thereby, a gentle bend is imparted to the fiber to obtain a natural appearance, and the close adhesion between the fibers is reduced, so the combability is also improved. In this gear crimping process, generally, the fiber is passed between two meshing gears in a state where the fiber is heated above the softening temperature, and the shape of the gear is transferred to show the fiber bend. In addition, if necessary, by heat-treating the core-sheath composite fiber for artificial hair at different temperatures in the fiber processing stage, different shapes of crimps can be shown.

[0092] <Headgear product>

[0093] The core-sheath composite fiber for artificial hair can be used without particular limitation as long as it is a headgear product. For example, it can be used for wig caps, wigs, hair curtains, hair extensions, hair braids, hair ornaments, and doll hair, etc.

[0094] The headdress product can also be composed only of the core-sheath composite fiber for artificial hair of the present invention, or other artificial hair fibers, natural fibers such as human hair and animal hair can be combined in the core-sheath composite fiber for artificial hair of the present invention.

[0095] Examples

[0096] Hereinafter, the present invention will be further specifically described based on examples. It should be noted that the present invention is not limited to these examples.

[0097] The measurement methods and evaluation methods used in the examples and comparative examples are as described below.

[0098] (Single fiber fineness)

[0099] Measurement was carried out using an automatic vibration type fineness measuring instrument "DENIER COMPUTER type DC-11" (manufactured by Search Co., Ltd.), and the average value of the measurement values of 30 samples was calculated as the single fiber fineness.

[0100] (Core-sheath ratio)

[0101] At room temperature, the fiber bundle was tied up and fixed with a shrink tube to prevent the fiber bundle (total fineness 550 dtex) from shifting, and then cut into circular pieces with a knife to prepare a fiber bundle for cross-section observation. The fiber bundle was photographed at a magnification of 500 times with a laser microscope (manufactured by KEYENCE CORPORATION, "VK-9500"), and the core-sheath ratio was evaluated based on the obtained fiber cross-section photograph.

[0102] (Color tone measurement)

[0103] The color of the core part or the sheath part was measured by observing the cross-section with a digital microscope (VHX-60 of KEYENCE Corporation), and the RGB values of the core part or the sheath part were determined by digitizing the color information, and L*a*b* was obtained from the RGB values.

[0104] (Appearance evaluation)

[0105] The appearance of the fibers in the examples and comparative examples was evaluated by a professional beautician, and the evaluation was carried out according to the following four-level criteria.

[0106] A: Equivalent to the appearance of human hair (having a deep color tone, showing an appearance with depth and being extremely good)

[0107] B: Almost equivalent to the appearance of human hair (having a deep color tone, showing an appearance with depth and being good)

[0108] C: Inferior to human hair in appearance

[0109] D: Very poor appearance, considerably inferior to human hair

[0110] (Example 1)

[0111] Relative to 100 parts by weight of polyethylene terephthalate pellets (manufactured by East West Chemical Private Limited, trade name "A-12" of EastPET) dried to a moisture content of 100 ppm or less, 20 parts by weight of a brominated epoxy-based flame retardant (manufactured by Sakamoto Pharmaceutical Co., Ltd., trade name "SR-T2MP"), 2 parts by weight of sodium antimonate (manufactured by Nippon Seiko Co., Ltd., trade name "SA-A"), 2 parts by weight of a black pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM22367BLACK(20)", pigment: 20% by weight, base resin: polyester resin), 0.7 parts by weight of a yellow pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM1001YELLOW(20)", pigment: 20% by weight, base resin: polyester resin), and 0.5 parts by weight of a red pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM3005RED(20)", pigment: 20% by weight, base resin: polyester resin) are added. After dry blending, it is supplied to a twin-screw extruder and melt-kneaded at a barrel set temperature of 280°C. After pelletization, it is dried to a moisture content of 100 ppm or less to obtain a polyester resin composition.

[0112] Next, relative to 100 parts by weight of nylon 6 (manufactured by UNITIKA, trade name "A1030BRL") dried to a moisture content of 1000 ppm or less, 12 parts by weight of a brominated epoxy-based flame retardant (manufactured by Sakamoto Pharmaceutical Co., Ltd., trade name "SR-T2MP"), 2 parts by weight of sodium antimonate (manufactured by Nippon Seiko Co., Ltd., trade name "SA-A"), 0.2 parts by weight of a black pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM22367BLACK(1)", pigment: 20% by weight, base resin: polyester resin), 0.1 parts by weight of a yellow pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM1001YELLOW(20)", pigment: 20% by weight, base resin: polyester resin), and 0.2 parts by weight of a red pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM3005RED(1)", pigment: 20% by weight, base resin: polyester resin) are added. After dry blending, it is supplied to a twin-screw extruder and melt-kneaded at a barrel set temperature of 260°C. After pelletization, it is dried to a moisture content of 1000 ppm or less to obtain a polyamide resin composition.

[0113] Subsequently, the granular polyester resin composition and polyamide resin composition were respectively supplied to an extruder, extruded from a concentric core-sheath type composite spinning nozzle (number of holes: 120, hole diameter: 1.5 mm) at a set temperature of 280°C, and wound at a speed of 40 to 200 m / minute to obtain an unstretched core-sheath composite fiber having a core-sheath ratio of core:sheath = 5:5 by area ratio, with the polyester resin composition as the core and the polyamide resin composition as the sheath.

[0114] The obtained unstretched fiber was drawn at a speed of 45 m / minute while being pulled using a hot roll at 85°C to produce a three-fold drawn fiber, and then continuously wound and heat-treated using a hot roll heated to 200°C at a speed of 45 m / minute. After attaching a polyether-based oil agent (manufactured by Enryo Yuka Kogyo Co., Ltd., trade name "KWC-Q") to make it 0.20% omf (percentage of the pure weight of the oil agent relative to the weight of the dry fiber), it was dried to obtain a core-sheath composite fiber having Figure 1 the cross-sectional shape shown in Figure 1 (single fiber fineness: 58.3 dtex).

[0115] For the obtained core-sheath composite fiber for artificial hair, a fiber bundle with a fiber length of 30 cm and a weight of 5 g was bent at the center and fixed with a binding band to make a hair bundle. Subsequently, 4 mL of a leveling agent (manufactured by DyStar Japan Co., Ltd., trade name "Sera Gal P-BMO (10%)") was added to an aqueous solution adjusted to be 1.0% omf with a yellow disperse dye (manufactured by Huntsman Corporation, trade name "Terasil Yellow 2GW") to adjust the dyeing solution, and acetic acid (2%) was used to adjust the pH to 4. The above dyeing solution was adjusted in a beam dyeing machine, and the solution temperature at this time was set to 50°C. The made hair bundle was immersed in the above solution. Then, the dyeing solution impregnated with the above hair bundle was heated to 130°C at a rate of 1°C / minute. It was treated at a dyeing temperature of 130°C for 60 minutes, the obtained fiber was taken out, and washed with water for 10 minutes. After washing with water, it was dried using a heat-uniform drying machine at 60°C for 1 hour.

[0116] (Example 2)

[0117] The resin used in the sheath was set to nylon 66 (manufactured by Toray Industries, Inc., trade name "AMILAN CM3001"), the set temperature of the drum during granulation was set to 280°C, the set temperature of the nozzle was set to 280°C, the core-sheath ratio was set to core:sheath = 7:3 by area ratio, and no pigment masterbatch was added to the nylon 66. Otherwise, the same operations as in Example 1 were carried out to obtain a core-sheath composite fiber (single fiber fineness: 61.5 dtex).

[0118] (Example 3)

[0119] The resin used in the sheath part was set as nylon 66 (manufactured by Toray Industries, Inc., trade name "AMILAN CM3001"). The set temperature of the roller during pelletization was set at 280°C, the set temperature of the nozzle was set at 280°C, and the core-sheath ratio was set with the core:sheath as 3:7 in terms of area ratio. Other than that, the same operations as in Example 1 were carried out to obtain core-sheath composite fibers (single fiber fineness 55.1 dtex).

[0120] (Example 4)

[0121] The resin used in the core part was set as polybutylene terephthalate pellets (manufactured by Mitsubishi Chemical Corporation, trade name "NOVADURAN 5020"). The set temperature of the roller during pelletization was set at 260°C, and no pigment masterbatch was added to nylon 6. Other than that, the same operations as in Example 1 were carried out to obtain core-sheath composite fibers (single fiber fineness 58.3 dtex).

[0122] (Example 5)

[0123] A polyamide-based resin composition was used for the core part, a polyester-based resin composition was used for the sheath part, and the core-sheath ratio was set with the core:sheath as 7:3 in terms of area ratio. Other than that, the same operations as in Example 1 were carried out to obtain core-sheath composite fibers (single fiber fineness 61.5 dtex).

[0124] (Comparative Example 1)

[0125] No pigment masterbatch was added to the polyester-based resin composition in the core part, and the pigment formulation of the polyamide-based resin composition in the sheath part was set as 2 parts by weight of black pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM22367BLACK(20)"), 0.7 parts by weight of yellow pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM1001YELLOW(20)"), and 0.5 parts by weight of red pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM3005RED(20)"). Other than that, the same operations as in Example 1 were carried out to obtain core-sheath composite fibers (single fiber fineness 58.3 dtex).

[0126] (Comparative Example 2)

[0127] The pigment formulation of the polyamide-based resin composition for the sheath part was set as 2 parts by weight of a black pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM22367BLACK(20)"), 0.7 parts by weight of a yellow pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM1001YELLOW(20)"), and 0.5 parts by weight of a red pigment masterbatch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "PESM3005RED(20)"). Except for this, the same operations as in Example 1 were carried out to obtain a core-sheath composite fiber (single fiber fineness: 58.3 dtex).

[0128] (Comparative Example 3)

[0129] Except for not adding a pigment masterbatch to the polyester-based resin composition in the core part, the same operations as in Example 1 were carried out to obtain a core-sheath composite fiber (single fiber fineness: 58.3 dtex).

[0130] (Comparative Example 4)

[0131] Except for not performing the dyeing process, the same operations as in Example 1 were carried out to obtain a core-sheath composite fiber (single fiber fineness: 58.3 dtex).

[0132] (Comparative Example 5)

[0133] Except for not performing the dyeing process, the same operations as in Example 2 were carried out to obtain a core-sheath composite fiber (single fiber fineness: 61.5 dtex).

[0134] For the core-sheath composite fibers (after dyeing) of the examples and comparative examples, the color tones of the core part and the sheath part were measured as described above, and the results are shown in Table 1 below. In addition, for the core-sheath composite fibers (after dyeing) of the examples and comparative examples, the appearance evaluation was carried out as described above, and the results are shown in Table 1 below. It should be noted that in Examples 1 to 5 and Comparative Examples 1 to 3, before performing the dyeing process, the color tones of the core part and the sheath part were measured as described above, and the results are shown in Table 1 below. It should be noted that in Table 1 below, the colors of the core part and the sheath part represent the colors before dyeing.

[0135]

[0136] As can be seen from Table 1 above, the core-sheath composite fibers of Examples 1 to 5 have a natural tone with depth comparable to that of human hair and good appearance because the brightness L* of the core is 10 or less and the brightness L* of the sheath is 15 or more. On the other hand, the core-sheath composite fibers of Comparative Examples 1, 3 to 5 do not have a natural tone with depth like that of human hair and do not have good appearance because the brightness L* of the core exceeds 10. The core-sheath composite fiber of Comparative Example 2 does not have a natural tone with depth like that of human hair and does not have good appearance even after dyeing because the brightness L* of the sheath is less than 15 and the combination of the colors of the core and the sheath before dyeing is dark colors.

[0137] The present invention is not particularly limited, and may include at least the following embodiments.

[0138] [1] A core-sheath composite fiber for artificial hair, characterized in that it is a core-sheath composite fiber for artificial hair comprising a core part and a sheath part,

[0139] The above core-sheath composite fiber for artificial hair is a colored fiber,

[0140] The brightness L* of the core part in the CIE1976 color space is 10 or less, and the brightness L* of the sheath part in the CIE1976 color space is 15 or more.

[0141] [2] The core-sheath composite fiber for artificial hair according to [1], wherein in the above core-sheath composite fiber for artificial hair, at least the core part contains a pigment.

[0142] [3] The core-sheath composite fiber for artificial hair according to [1] or [2], wherein both the core part and the sheath part are dyed.

[0143] [4] The core-sheath composite fiber for artificial hair according to any one of [1] to [3], wherein the core part of the above core-sheath composite fiber for artificial hair contains one or more polyester-based resins selected from the group consisting of alkylene glycol terephthalate and copolyester having alkylene glycol terephthalate as a main component.

[0144] [5] The core-sheath composite fiber for artificial hair according to any one of [1] to [4], wherein the sheath part of the above core-sheath composite fiber for artificial hair contains a polyamide-based resin having at least one selected from the group consisting of nylon 6 and nylon 66 as a main component.

[0145] [6] The core-sheath composite fiber for artificial hair according to any one of [1] to [5], wherein the brightness L* of the core part in the CIE1976 color space is 8 or less, and the brightness L* of the sheath part in the CIE1976 color space is 24 or more.

[0146] [7] The core-sheath composite fiber for artificial hair according to any one of [1] to [6], wherein the core-sheath ratio of the core-sheath composite fiber for artificial hair in the fiber cross-section is core:sheath = 1:9 to 9:1 in terms of area ratio.

[0147] [8] A headdress product, characterized by comprising the core-sheath composite fiber for artificial hair according to any one of [1] to [7].

[0148] [9] The headdress product according to [8], wherein the headdress product is one selected from the group consisting of a wig cap, a wig, a hair curtain, hair extensions, a hair braid, a hair accessory, and doll hair.

[0149]

[10] A method for manufacturing a core-sheath composite fiber for artificial hair, characterized in that it is a method for manufacturing the core-sheath composite fiber for artificial hair according to any one of [1] to [7],

[0150] comprising a step of melt-spinning a core resin composition and a sheath resin composition using a core-sheath type composite nozzle, and a step of dyeing the core-sheath composite fiber for artificial hair,

[0151] at least the core resin composition contains a pigment.

[0152]

[11] The method for manufacturing a core-sheath composite fiber for artificial hair according to

[10] , wherein the pigment is composed of three pigment masterbatches of black, red, and yellow.

[0153] Explanation of symbols

[0154] 1 Core-sheath composite fiber for artificial hair (cross-section)

[0155] 10 Core part

[0156] 20 Sheath part

Claims

1. A core-sheath composite fiber for artificial hair, characterized in that, It is a core-sheath composite fiber for artificial hair containing a core part and a sheath part. The core-sheath composite fiber for artificial hair is a colored fiber. The core-sheath composite fiber for artificial hair is a concentric core-sheath type. Either the core part or the sheath part of the core-sheath composite fiber for artificial hair contains one or more polyester-based resins selected from the group consisting of alkylene glycol terephthalate and copolyester having alkylene glycol terephthalate as the main component, and the other contains a polyamide-based resin having at least one selected from the group consisting of nylon 6 and nylon 66 as the main component. Both the core part and the sheath part contain pigments, and both the core part and the sheath part are dyed with dyes. The brightness L* of the core part in the CIE1976 color space is 8 or less, and the brightness L* of the sheath part in the CIE1976 color space is 24 or more. The so-called "copolyester having alkylene glycol terephthalate as the main component" means a copolyester containing 80 mol% or more of alkylene glycol terephthalate. The so-called "polyamide-based resin having at least one selected from the group consisting of nylon 6 and nylon 66 as the main component" means a polyamide-based resin containing 80 mol% or more of nylon 6 and / or nylon 66.

2. The sheath-core composite fiber for artificial hair according to claim 1, wherein, The core part of the core-sheath composite fiber for artificial hair contains one or more polyester-based resins selected from the group consisting of alkylene glycol terephthalate and copolyester having alkylene glycol terephthalate as the main component. The sheath part of the core-sheath composite fiber for artificial hair contains a polyamide-based resin having at least one selected from the group consisting of nylon 6 and nylon 66 as the main component.

3. The sheath-core composite fiber for artificial hair according to claim 1, wherein, The core part of the core-sheath composite fiber for artificial hair contains a polyamide-based resin having at least one selected from the group consisting of nylon 6 and nylon 66 as the main component. The sheath part of the core-sheath composite fiber for artificial hair contains one or more polyester-based resins selected from the group consisting of alkylene glycol terephthalate and copolyester having alkylene glycol terephthalate as the main component.

4. The sheath-core composite fiber for artificial hair according to any one of claims 1 to 3, wherein, In the core-sheath ratio of the core-sheath composite fiber for artificial hair in the fiber cross-section, the core:sheath is 1:9 to 9:1 in terms of area ratio.

5. The sheath-core composite fiber for artificial hair according to any one of claims 1 to 3, wherein, The brightness L* of the core part in the CIE1976 color space is 5 or more.

6. The sheath-core composite fiber for artificial hair according to any one of claims 1 to 3, wherein, The brightness L* of the sheath part in the CIE1976 color space is 40 or less.

7. A headgear product, characterized in that, It contains the core-sheath composite fiber for artificial hair according to any one of claims 1 to 6.

8. The headgear article according to claim 7, wherein, The headgear product is one selected from the group consisting of a wig cap, a wig, a hair curtain, hair extensions, a hair braid, a hair accessory, and doll hair.

9. A manufacturing method of a core-sheath composite fiber for artificial hair, characterized in that, It is a method for manufacturing the core-sheath composite fiber for artificial hair according to any one of claims 1 to 6. It includes a step of melt-spinning a core resin composition and a sheath resin composition using a core-sheath type composite nozzle, and a step of dyeing the core-sheath composite fiber for artificial hair with a dye. The core resin composition and the sheath resin composition contain pigments.

10. The manufacturing method of the core-sheath composite fiber for artificial hair according to claim 9, wherein, The pigment is composed of three pigment masterbatches of black, red, and yellow.

11. The method for manufacturing a core-sheath composite fiber for artificial hair according to claim 9, wherein, The dye contains a yellow disperse dye.

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