WO2022145114A1

WO2022145114A1 - Core-sheath composite fiber for artificial hair, headwear product comprising same, and method for producing same

Info

Publication number: WO2022145114A1
Application number: PCT/JP2021/038781
Authority: WO
Inventors: 安友徳和
Original assignee: 株式会社カネカ
Priority date: 2020-12-28
Filing date: 2021-10-20
Publication date: 2022-07-07
Also published as: JPWO2022145114A1; US20230416946A1

Abstract

One or more embodiments of the present invention relate to a core-sheath composite fiber for artificial hair, said core-sheath composite fiber comprising a core part and a sheath part, wherein: the core part is configured from a polyester resin composition that contains a polyester resin as a main component; the sheath part is configured from a polyamide resin composition that contains a polyamide resin as a main component; the core-sheath ratio in the composite fiber for artificial hair, namely the (core part):(sheath part) area ratio is from 2:8 to 7:3; both the fiber cross-section and the core part cross-section have a flattened cross-sectional shape; the major axis direction of the fiber cross-section and the major axis direction of the core part cross-section generally coincide with each other; and the eccentricity ratio of the fiber in the minor axis direction is 5% or more. Consequently, the present invention provides a fiber for artificial hair, said fiber having a texture and appearance close to those of human hair, while exhibiting good curl setting properties.

Description

Core-sheath composite fiber for artificial hair, headdress products containing it, and its manufacturing method

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 producing the same.

Human hair has traditionally been used in headdress products such as wigs, hair wigs, hair attachments, hair bands, and doll hair. However, in recent years, it has become difficult to obtain human hair, and there is a demand for artificial hair to replace human hair. It is increasing. Examples of the material for artificial hair include synthetic fibers such as acrylic fibers, vinyl chloride fibers, vinylidene chloride fibers, polyester fibers, polyamide fibers, and polyolefin fibers. For example, Patent Document 1 describes, as a fiber for artificial hair, a core-sheath composite fiber containing a polyester-based resin as a core component and a polyamide-based resin as a sheath component. In Patent Document 1, polyethylene terephthalate having a high degree of polymerization and polyamide having a high degree of polymerization are used, and in a melt spinning method, after quenching and solidification by liquid cooling, the fibers are passed through a fiber surface layer crystallization promoting device to specify streaks on the fiber surface. By imparting the uneven structure of, the strength of the fiber is ensured, the gloss of the polyamide of the sheath is suppressed, the texture is close to that of human hair, and the fiber for artificial hair having excellent durability and heat resistance can be obtained. It is stated that.

On the other hand, curl setability and curl retention are also characteristics required for artificial hair. Attempts have been made to improve these characteristics by controlling the material and cross-sectional shape of the fiber. For example, in Patent Document 2, the core portion and the sheath portion are formed, and the long axis direction of the fiber cross section and the long axis direction of the core portion are omitted. Artificial hair that is consistent and has an eccentricity of 5% or more in the long axis direction, has a feel and appearance similar to human hair, has good curl without curling, and has extremely high curl retention. It is described that core sheath composite fibers can be obtained.

Japanese Unexamined Patent Publication No. 3-185103 International Publication No. 2018/179803

However, although the artificial hair fiber using a polyamide resin for the sheath portion as described in Patent Document 1 has a good tactile sensation and durability, there is a problem that the curl settability is deteriorated. Further, the artificial hair fiber having a structure eccentric in the long axis direction as described in Patent Document 2 has latent crimpability, and an artificial hair fiber having high curl retention can be obtained without curling. , When curling is applied by a hair iron or the like, there is a problem that the curl setting property is poor.

The present invention provides an artificial hair fiber having a tactile sensation and appearance similar to human hair and having good curl settability in order to solve the above-mentioned conventional problems.

The present invention is, in one or more embodiments, a core-sheath composite fiber for artificial hair including a core portion and a sheath portion, wherein the core portion is composed of a polyester-based resin composition containing a polyester-based resin, and the sheath portion. Is composed of a polyamide-based resin composition containing a polyamide-based resin, and in the composite fiber for artificial hair, the core-sheath ratio is an area ratio of 2: 8 to 7: 3, and the fiber cross section is The cross section of the core has a flat cross-sectional shape, the long axis direction of the fiber cross section and the long axis direction of the core section are substantially the same, and the eccentricity of the fiber in the short axis direction is 5% or more. The present invention relates to a core-sheath composite fiber for artificial hair.

The present invention also relates to a headdress product comprising the core-sheath composite fiber for artificial hair in one or more embodiments.

The present invention is also a method for producing the core-sheath composite fiber for artificial hair according to one or more embodiments, wherein the polyester-based resin composition and the polyamide-based resin composition are melt-spun using the core-sheath composite nozzle. Including the step, the cross-sectional shape of the core-sheath composite fiber for artificial hair and the core portion is made flat, the long axis direction of the fiber cross section and the long axis direction of the core section are substantially matched, and the eccentricity in the short axis direction of the fiber is 5. The present invention relates to a method for producing a core-sheath composite fiber for artificial hair, which is characterized by having a content of% or more.

According to the present invention, it is possible to provide a core-sheath composite fiber for artificial hair having a feel and appearance similar to that of human hair and having good curl settability, and a headdress product containing the same.

According to the production method of the present invention, it is possible to obtain a core-sheath composite fiber for artificial hair, which has a feel and appearance similar to that of human hair and has good curl settability.

FIG. 1 is a schematic view showing a fiber cross section of a core-sheath composite fiber for artificial hair according to one or more embodiments of the present invention. FIG. 2 is a laser micrograph of a fiber cross section of the fiber of Example 1. FIG. 3 is a laser micrograph of a fiber cross section of the fiber of Comparative Example 1.

As a result of diligent studies to solve the above problems, the present inventor has a polyester-based resin composition containing a polyester-based resin as a main component in a core-sheath composite fiber for artificial hair including a core portion and a sheath portion. It is composed of a material, and the sheath portion is composed of a polyamide-based resin composition containing a polyamide-based resin as a main component, and the core-sheath ratio is an area ratio of 2: 8 to 7: 3 for the core portion: sheath portion, and the fiber cross section and the fiber cross section and A polyamide resin is used by making the shape of the core cross section flat, making the fiber cross section long axis direction substantially coincide with the core cross section long axis direction, and setting the eccentricity in the short axis direction of the fiber to 5% or more. As a result, the poor curl settability that tends to occur can be improved, and the core-sheath composite fiber for artificial hair that has a feel and appearance close to that of human hair and has good curl-setability (hereinafter, also simply referred to as "core-sheath composite fiber"). .) Was obtained, and the present invention was reached.

(Fiber shape)
The core-sheath composite fiber for artificial hair according to one or more embodiments of the present invention includes a core portion and a sheath portion, and both the fiber cross section and the core portion cross section have a flat cross-sectional shape. Examples of the flat shape include an elliptical shape, a flat multilobed shape, and an oval shape. Examples of the flat polyleaf shape include a shape in which two or more leaf shapes selected from the group consisting of a circular shape and an elliptical shape are connected via a concave portion. In the flat multilobed form, the circular and / and elliptical forms partially overlap at the junction. The cross-sectional shape of the fiber cross section is preferably a flat multi-leaf shape, and more preferably a flat bi-leaf shape. The circular or elliptical shape does not necessarily have to draw a continuous arc, and includes a substantially elliptical shape that is partially deformed unless it has an acute angle. Further, it is not necessary to consider the unevenness of 2 μm or less generated on the cross section of the fiber and the outer periphery of the core portion due to the inclusion of additives and the like.

In the fiber cross section of the core-sheath composite fiber for artificial hair according to one or more embodiments of the present invention, the maximum of a straight line connecting arbitrary two points on the outer periphery of the fiber cross section so as to be parallel to the line symmetry axis and the line symmetry axis. When connecting the length of the long axis of the fiber cross section, which is a straight line to be long, and any two points on the outer circumference of the fiber cross section so as to be perpendicular to the long axis of the fiber cross section, the two points that become the maximum length are defined. It is preferable that the length of the first minor axis of the fiber cross section, which is a straight line to be connected, satisfies the following formula (1).
Length of fiber cross-section major axis / Length of fiber cross-section first minor axis = 1.1 or more and 2.0 or less (1)

Further, in the fiber cross section, the length of the core section long axis, which is the longest straight line among the straight lines connecting arbitrary two points on the outer periphery of the core section so as to be parallel to the line symmetry axis and the line symmetry axis. The first short axis of the core cross section, which is a straight line connecting two points having the maximum length when connecting arbitrary two points on the outer periphery of the core cross section so as to be perpendicular to the core cross section long axis. It is preferable that the length of is satisfied by the following formula (2).
Core cross-section long axis length / core cross-section first minor axis length = 1.3 or more and 2.0 or less (2)

The core-sheath composite fiber for artificial hair has a flat multi-leaf shape fiber cross section, so that two or more leaf shapes consisting of a circular shape and an elliptical shape are connected via a concave portion, and the fiber surface has smooth irregularities. Therefore, the contact area between fibers or when passing through a comb is small, and it is easy to realize a tactile sensation close to that of human hair and good combability.

Further, in the core-sheath composite fiber for artificial hair, the long axis direction of the fiber cross section and the core cross section is substantially the same. In one or more embodiments of the present invention, "the long axis directions of the fiber cross section and the core cross section are substantially the same" means that the angle formed by the fiber cross section long axis and the core long axis is less than 15 degrees. means. When the long axis directions of the fiber cross section and the core cross section are substantially the same, and the ratio of the length of the long axis of the core cross section to the length of the first minor axis of the core cross section is within the above range, the fiber cross section is determined. Since the outer peripheral shape of the fiber cross section and the outer peripheral shape of the core cross section are close to each other, the fiber can be separated and the core can be exposed to the surface by peeling off the two components while maintaining a good tactile sensation and appearance as artificial hair. Can be prevented. Further, there is an advantage in molding processing that the change between the shape of the ejection from the nozzle and the shape of the fiber cross section after molding is small, and the nozzle design for realizing the above-mentioned cross-sectional shape becomes easy. In addition, since the long axis directions of the fiber cross section and the core cross section are substantially the same, the anisotropy of the flexural modulus derived from the moment of inertia of area also matches the fiber as a whole and the core, and artificial touch and combing are performed. The quality required for hair can also be easily adjusted.

The eccentricity of the core-sheath composite fiber for artificial hair in the minor axis direction is 5% or more, preferably 5% or more and 50% or less, more preferably 6% or more and 40% or less, still more preferably 10%. It is 30% or more, and even more preferably 12% or more and 25% or less. When the fiber cross section is flat, the flexural modulus of the fiber has anisotropy in the major axis direction and the minor axis direction, but when curling with a hair iron or pipe winding, the fiber has a small flexural modulus. It is bent in the axial direction and heated while being distorted. By setting the eccentricity ratio in the minor axis direction within the above range, a large strain is applied to the resin in the core portion as compared with the case where there is no eccentricity, and strong curl is generated in the fiber after setting. Further, in the case of a fiber eccentric in the long axis direction, a twisting moment generated in the fiber cross section is likely to work, and the fiber is crimped in an unintended direction, resulting in an unnatural appearance. On the other hand, when the fiber is eccentric in the minor axis direction, the twisting moment generated in the fiber cross section is smaller and the latent crimping property caused by the eccentricity is smaller than in the case of eccentricity in the major axis direction. Can be suppressed and a natural appearance can be realized.

The eccentricity of the core-sheath composite fiber for artificial hair in the minor axis direction is the length of the first minor axis of the fiber cross section, the center point of the first minor axis of the fiber cross section, and the center of the first minor axis of the core cross section in the fiber cross section. It can be calculated by the following equation (3) based on the distance between two points. The distance between the center point of the first minor axis of the fiber cross section and the center point of the first minor axis of the core cross section is a straight line that passes through the center point of the first minor axis of the fiber cross section and intersects the first minor axis of the fiber cross section perpendicularly. It means the distance between straight lines passing through the center point of the first short axis of the cross section of the core and perpendicularly intersecting the first short axis of the cross section of the core.
Eccentricity in the minor axis direction (%) = Distance between two points between the center point of the first minor axis of the fiber cross section and the center point of the first minor axis of the core / (length of the first minor axis of the fiber cross section / 2) × 100 (3)

FIG. 1 is a schematic view showing a fiber cross section of the core-sheath composite fiber for artificial hair according to one or more embodiments of the present invention. The core-sheath composite fiber 1 for artificial hair of the embodiment includes a sheath portion 10 and a core portion 20. The core-sheath composite fiber 1 for artificial hair of the embodiment has a flat bilobed cross-sectional shape in which two elliptical shapes are connected via two recesses, and the core portion 20 has an elliptical cross-sectional shape. In the flat bilobed form, the two ellipses partially overlap at the junction.

In the core-sheath composite fiber 1 for artificial hair of the embodiment, the length L of the long axis 11 of the fiber cross section and the length S1 of the first short axis 12 of the fiber cross section satisfy the above formula (1), that is, L / S1. It is preferably 1.1 or more and 2.0 or less.

Further, in the core-sheath composite fiber 1 for artificial hair of the embodiment, the length Lc of the core cross-section long axis 21 and the length Sc1 of the core cross-section first minor axis 22 satisfy the above formula (2), that is, It is preferable that Lc / Sc1 is 1.3 or more and 2.0 or less.

Further, in the core-sheath composite fiber 1 for artificial hair of the embodiment, the eccentricity (%) in the minor axis direction is the length S1 of the first minor axis of the fiber cross section and the center point 13 of the first minor axis 12 of the fiber cross section. It can be calculated as follows based on the distance d between the two points of the center point 23 of the core portion first short axis 22 (that is, the distance between the fiber cross-sectional long axis 11 and the core section long axis 21).
Eccentricity in the minor axis direction (%) = d / (S1 / 2) × 100

The cross-sectional shape of the fiber and the core described above can be controlled by using a nozzle (hole) having a shape close to the desired cross-sectional shape.

The cross-sectional shape of the core is flat, and is not particularly limited as long as the long axis direction of the fiber cross section and the long axis direction of the core cross section are substantially the same. The ratio of the lengths of the above is preferably within the above range, and an elliptical shape, a flat polylobed shape such as a flat bilobed shape, and the like are more preferably used.

The core-sheath ratio of the core-sheath composite fiber for artificial hair is in the range of core: sheath = 2: 8 to 7: 3 in terms of area ratio. When the core-sheath ratio is in this range, the bending rigidity value as a physical property related to the tactile sensation and texture becomes close to that of human hair, so that a core-sheath composite fiber for artificial hair having the same quality as human hair can be obtained. If the number of cores is less than this range, the bending rigidity value is lower than that of human hair, so that the core-sheath composite fiber for artificial hair of the same quality as human hair cannot be obtained. The bending rigidity value becomes too large and does not resemble human hair, and the sheath portion becomes extremely thin, so that the core portion is easily exposed and the core portion and the sheath portion are easily peeled off. From the viewpoint of obtaining the same feel and texture as human hair, the core-sheath ratio of the core-sheath composite fiber for artificial hair is preferably in the range of 3: 7 to 7: 3 in terms of area ratio. More preferably, it is in the range of 3: 7 to 6: 4. In the fiber cross section of the core-sheath composite fiber for artificial hair, in order to prevent the core and the sheath from peeling off, it is preferable that the core is not exposed on the fiber surface and is completely covered by the sheath.

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

The core-sheath composite fiber for artificial hair according to one or more embodiments of the present invention does not necessarily have to have the same fineness, core-sheath ratio, and cross-sectional shape as an aggregate of fibers, for example, a fiber bundle. Fibers having different fineness, core-sheath ratio, and cross-sectional shape may be mixed.

In the core-sheath composite fiber for artificial hair, the core portion is composed of a polyester-based resin composition containing a polyester-based resin as a main component, and the sheath portion is composed of a polyamide-based resin composition containing a polyamide-based resin as a main component. ..

In one or more embodiments of the present invention, the polyester resin composition containing a polyester resin as a main component is 50% by weight or more of the polyester resin when the total weight of the polyester resin composition is 100% by weight. It means that it contains a large amount, and it is preferable to contain 60% by weight or more of the polyester resin, more preferably 70% by weight or more, further preferably 80% by weight or more, and further preferably 90% by weight or more. , 95% by weight or more is even more preferable.

As the polyester resin, it is preferable to use one or more selected from the group consisting of polyalkylene terephthalate and copolymerized polyester mainly composed of polyalkylene terephthalate. In one embodiment of the present invention, the "copolymerized polyester mainly composed of polyalkylene terephthalate" refers to a copolymerized polyester containing 80 mol% or more of polyalkylene terephthalate.

The polyalkylene terephthalate is not particularly limited, and examples thereof include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polycyclohexanedimethylene terephthalate.

The copolymerized polyester mainly composed of the polyalkylene terephthalate is not particularly limited, but is mainly composed of polyalkylene terephthalate such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polycyclohexanedimethylene terephthalate, and other copolymerization components. Examples thereof include copolymerized polyester containing.

Examples of the other copolymerization components include isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid, trimellitic acid, pyromellitic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, and sebacine. Polyvalent carboxylic acids such as acids, dodecanedioic acids and their derivatives; dicarboxylic acids including sulfonates such as 5-sodium sulfoisophthalic acid, 5-sodium sulfoisophthalate dihydroxyethyl and their derivatives; 1,2-propane Didiol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, diethylene glycol, polyethylene glycol, trimethylolpropane, pentaerythritol, 4-hydroxy Examples thereof include benzoic acid, ε-caprolactone, and ethylene glycol ether of bisphenol A.

From the viewpoint of stability and ease of operation, the copolymerized polyester is preferably produced by reacting the main polyalkylene terephthalate with a small amount of other copolymerizing components. As the polyalkylene terephthalate, a polymer of terephthalic acid and / or a derivative thereof (for example, methyl terephthalate) and alkylene glycol can be used. The copolymerized polyester is a mixture of terephthalic acid and / or a derivative thereof (for example, methyl terephthalate) used for the polymerization of the main polyalkylene terephthalate and alkylene glycol, and a monomer or a monomer which is a small amount of other copolymerization components. It may be produced by polymerizing a product containing an oligomer component.

The copolymerized polyester may be polycondensed with the other copolymerization components on the main chain and / or side chain of the main polyalkylene terephthalate, and the copolymerization method and the like are not particularly limited.

Specific examples of the copolymerized polyester containing polyalkylene terephthalate as a main component include, for example, ethylene glycol ether of bisphenol A, 1,4-cyclohexadimethanol, isophthalic acid and dihydroxy 5-sodium sulfoisophthalate containing polyethylene terephthalate as a main component. Examples thereof include polyester obtained by copolymerizing a kind of compound selected from the group consisting of ethyl.

The polyalkylene terephthalate and the copolymerized polyester mainly composed of the polyalkylene terephthalate may be used alone or in combination of two or more. Among them, polyethylene terephthalate; polypropylene terephthalate; polybutylene terephthalate; polyester mainly composed of polyethylene terephthalate and copolymerized with ethylene glycol ether of bisphenol A; polyester mainly composed of polyethylene terephthalate and copolymerized with 1,4-cyclohexanedimethanol; polyester. It is preferable to use polyester mainly composed of terephthalate and copolymerized with isophthalic acid; and polyester mainly composed of polyethylene terephthalate and copolymerized with dihydroxyethyl 5-sodium sulfoisophthalate alone or in combination of two or more.

The intrinsic viscosity (sometimes referred to as IV value) of the polyester resin is not particularly limited, but is preferably 0.3 dL / g or more and 1.2 dL / g or less, and 0.4 dL / g or more and 1.0 dL / g. It is more preferably g or less. When the intrinsic viscosity is 0.3 dL / g or more, the mechanical strength of the obtained fiber does not decrease and there is no risk of drip during the combustion test. Further, when the intrinsic viscosity is 1.2 dL / g or less, the molecular weight does not increase too much, the melt viscosity does not become too high, melt spinning becomes easy, and the fineness tends to be uniform.

The polyester-based resin composition may contain other resins in addition to the polyester-based resin. Examples of other resins include polyamide-based resins, vinyl chloride-based resins, modaacrylic-based resins, polycarbonate-based resins, polyolefin-based resins, and polyphenylene sulfide-based resins. As for other resins, one type may be used alone, or two or more types may be used in combination.

In one or more embodiments of the present invention, the polyamide-based resin composition containing a polyamide-based resin as a main component is more than 50% by weight when the total weight of the polyamide-based resin composition is 100% by weight. It means that the polyamide resin is contained in an amount of 60% by weight or more, more preferably 70% by weight or more, further preferably 80% by weight or more, still more preferably 90% by weight or more. It is even more preferable to contain 95% by weight or more.

The polyamide resin is obtained by polymerizing one or more selected from the group consisting of lactam, a mixture of aminocarboxylic acid, dicarboxylic acid and diamine, a mixture of dicarboxylic acid derivative and diamine, and a salt of dicarboxylic acid and diamine. It means nylon resin.

Specific examples of the lactam include, but are not limited to, 2-azetidinone, 2-pyrrolidinone, δ-valerolactam, ε-caprolactam, enantractam, caprilactam, undecalactam, laurolactam and the like. can. Of these, ε-caprolactam, undecalactam, and laurolactam are preferable, and ε-caprolactam is particularly preferable. These lactams may be used alone or in mixtures of two or more.

Specific examples of the aminocarboxylic acid are not particularly limited, but for example, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, and the like. Examples include 12-aminododecanoic acid. Of these, 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid are preferable, and 6-aminocaproic acid is particularly preferable. These aminocarboxylic acids may be used alone or in a mixture of two or more.

Specific examples of the dicarboxylic acid used in the mixture of dicarboxylic acid and diamine, the mixture of dicarboxylic acid derivative and diamine, or the salt of dicarboxylic acid and diamine are not particularly limited, but for example, oxalic acid, malonic acid, succinic acid, and the like. Aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brushphosphoric acid, tetradecanedioic acid, pentadecanedioic acid, octadecanedioic acid, cyclohexanedicarboxylic acid Examples thereof include aromatic dicarboxylic acids such as alicyclic dicarboxylic acids, phthalic acids, isophthalic acids, terephthalic acids, and naphthalenedicarboxylic acids. Of these, adipic acid, sebacic acid, dodecanedioic acid, terephthalic acid, and isophthalic acid are preferable, and adipic acid, terephthalic acid, and isophthalic acid are particularly preferable. These dicarboxylic acids may be used alone or in a mixture of two or more.

Specific examples of the diamine used in the mixture of dicarboxylic acid and diamine, the mixture of dicarboxylic acid derivative and diamine, or the salt of dicarboxylic acid and diamine are not particularly limited, but for example, 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-diamino Decane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, 1,14-diaminotetradecane, 1,15-diaminopentanedecane, 1,16-diaminohexadecane, 1,17-diamino Aliper diamines such as heptadecane, 1,18-diaminooctadecane, 1,19-diaminononadecan, 1,20-diaminoeikosan, cyclohexanediamine, alicyclic diamines such as bis- (4-aminohexyl) methane, Examples thereof include aromatic diamines such as m-xylylene diamine and p-xylylene diamine. Of these, aliphatic diamines are particularly preferable, and hexamethylenediamine is particularly preferably used. These diamines may be used alone or in a mixture of two or more.

The polyamide-based resin (sometimes referred to as nylon resin) is not particularly limited, and is, for example, nylon 6, nylon 66, nylon 11, nylon 12, nylon 6/10, nylon 6/12, nylon 6T and / or. It is preferable to use semi-aromatic nylon containing 6I units, and copolymers of these nylon resins. In particular, a copolymer of nylon 6, nylon 66, nylon 6 and nylon 66 is more preferable.

The polyamide-based resin can be produced, for example, by a polyamide-based resin polymerization method in which a polyamide-based resin raw material is heated in the presence or absence of a catalyst. Stirring may or may not occur during the polymerization, but stirring is preferred to obtain a homogeneous product. The polymerization temperature can be arbitrarily set according to the degree of polymerization, the reaction yield, and the reaction time of the target polymer, but a low temperature is preferable in consideration of the quality of the finally obtained polyamide resin. The reaction rate can also be set arbitrarily. Although there is no limitation on the pressure, it is preferable to reduce the pressure inside the system in order to efficiently extract the volatile components to the outside of the system.

The polyamide resin used in the present invention may be terminated with a terminal blocking agent such as a carboxylic acid compound and an amine compound, if necessary. When the terminal is sealed by adding a monocarboxylic acid and / or a monoamine, the concentration of the terminal amino group or the terminal carboxyl group of the obtained nylon resin is lower than that when the terminal blocking agent is not used. On the other hand, when the terminal is blocked with a dicarboxylic acid or diamine, the sum of the concentrations of the terminal amino group and the terminal carboxyl group does not change, but the ratio of the concentration of the terminal amino group to the terminal carboxyl group changes.

Specific examples of the carboxylic acid compound are not particularly limited, but are, for example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, capric acid, pelargonic acid, undecanoic acid, lauric acid, tridecanoic acid, and myristic acid. , Myristoleic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, aliphatic monocarboxylic acids such as araquinic acid, alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid and methylcyclohexanecarboxylic acid, benzoic acid, toluic acid, Aromatic monocarboxylic acids such as ethyl benzoic acid and phenylacetic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brushlin Acids, aliphatic dicarboxylic acids such as tetradecanedioic acid, pentadecanedioic acid and octadecanedioic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid and naphthalenedicarboxylic acid. Can be mentioned.

Specific examples of the amine compound are not particularly limited, but for example, butylamine, pentylamine, hexylamine, heptylamine, octylamine, 2-ethylhexylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, and the like. Alicyclic monoamines such as tetradecylamine, pentadecylamine, hexadecylamine, octadecylamine, nonadesylamine and icosylamine, alicyclic monoamines such as cyclohexylamine and methylcyclohexylamine, aromatic monoamines such as benzylamine and β-phenylethylamine. 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-diaminohexadecan, 1,17-diaminoheptadecan, 1, , 18-Diaminooctadecane, 1,19-diaminononadecan, aliphatic diamines such as 1,20-diaminoeikosan, cyclohexanediamine, alicyclic diamines such as bis- (4-aminohexyl) methane, xylylene diamines, etc. Aromatic amines and the like.

The concentration of terminal groups in the polyamide resin is not particularly limited, but the one with a higher terminal amino group concentration is used when it is necessary to improve dyeability for fiber applications or when designing a material suitable for alloying for resin applications. Is preferable. On the contrary, when it is desired to suppress coloring or gelation under long-term aging conditions, it is preferable that the terminal amino group concentration is low. Furthermore, if you want to suppress lactam regeneration during remelting, thread breakage during melt spinning due to oligomer formation, mold deposit during continuous injection molding, and die mark generation during continuous extrusion of film, both the terminal carboxyl group concentration and the terminal amino group concentration are both. Lower is preferable. The terminal group concentration may be adjusted depending on the intended use, but both the terminal amino group concentration and the terminal carboxyl group concentration are preferably 1.0 × 10 ^-5 to 15.0 × 10 ^-5 eq / g, more preferably. 2.0 × 10 ^-5 to 12.0 × 10 ^-5 eq / g, particularly preferably 3.0 × 10 ^-5 to 11.0 × 10 ^-5 eq / g. In the present specification, the numerical range indicated by "...-..." includes both-end values as in the numerical range indicated by "... or more ... or less".

In addition, as a method of adding the terminal blocker, a method of adding the caprolactam at the same time as a raw material at the initial stage of polymerization, a method of adding it during the polymerization, and a method of adding the nylon resin when passing it through a vertical stirring thin film evaporator in a molten state. Etc. are adopted. The terminal blocker may be added as it is, or may be dissolved in a small amount of solvent and added.

The polyamide-based resin composition may contain other resins in addition to the polyamide-based resin. Examples of other resins include vinyl chloride resin, modal acrylic resin, polycarbonate resin, polyolefin resin, polyphenylene sulfide resin and the like. As for other resins, one type may be used alone, or two or more types may be used in combination.

The core-sheath composite fiber for artificial hair has a core made of polyalkylene terephthalate and polyalkylene terephthalate as a main component, from the viewpoint of making the tactile sensation and appearance closer to human hair and further improving curl settability and curl retention. It is preferable to use a polyester resin composition containing at least one polyester resin selected from the group consisting of polyester as a main component, and the sheath portion is mainly composed of at least one selected from the group consisting of nylon 6 and nylon 66. It is more preferable to use a polyamide-based resin composition containing the above-mentioned polyamide-based resin as a main component. In one embodiment of the present invention, the "polyamide-based resin mainly composed of at least one selected from the group consisting of nylon 6 and nylon 66" is a polyamide-based resin containing 80 mol% or more of nylon 6 and / or nylon 66. Means.

In one or more embodiments of the present invention, a pigment may be contained in the resin composition of the core portion or the sheath portion in order to obtain a core-sheath composite fiber for artificial hair having a desired color. The pigment is not particularly limited, and for example, a general pigment such as carbon black or anthraquinone can be used. A pigment masterbatch can also be used. A pigment masterbatch is a mixture of a pigment and a resin composition that is kneaded using a kneader such as an extruder to be pelletized (sometimes referred to as compounding), and is generally difficult to handle because it is in the form of fine powder. By pre-dispersing the pigment to be used in the resin composition, handling can be facilitated and coloring spots on the obtained fibers can be suppressed.

The amount of the pigment added to the polyester resin composition constituting the core portion is not particularly limited, but it is preferable that the pigment is contained in an amount of 0.005 part by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the polyester resin. It is more preferable to include 01 parts by weight or more and 1 part by weight or less. Further, the amount of the pigment added to the polyamide resin composition constituting the sheath portion is not particularly limited, but it is preferable that the pigment is contained in an amount of 0.005 part by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the polyamide resin. It is more preferable to contain 0.01 parts by weight or more and 1 part by weight or less.

In one or more embodiments of the present invention, a flame retardant may be used in combination from the viewpoint of flame retardancy. Examples of the flame retardant include a bromine-containing flame retardant and a phosphorus-containing flame retardant. Examples of the phosphorus-containing flame retardant include a phosphoric acid ester amide compound and an organic cyclic phosphorus-based compound. The bromine-based flame retardant is not particularly limited, and is, for example, a brominated epoxy flame retardant; pentabromotoluene, hexabromobenzene, decabromodiphenyl, decabromodiphenyl ether, bis (tribromophenoxy) ethane, tetrabromobisphenol phthalic acid. Bromine-containing phosphate esters such as ethylenebis (tetrabromophthalimide), ethylenebis (pentabromophenyl), octabromotrimethylphenylindan, tris (tribromoneopentyl) phosphate; brominated polystyrenes; brominated polybenzyl acrylate Classes; brominated phenoxy resins; brominated polycarbonate oligomers; tetrabromobisphenol A, tetrabromobisphenol A-bis (2,3-dibromopropyl ether), tetrabromobisphenol A-bis (allyl ether), tetrabromobisphenol A- Tetrabromobisphenol A derivatives such as bis (hydroxyethyl ether); bromine-containing triazine compounds such as tris (tribromophenoxy) triazine; bromine-containing isocyanuric acid compounds such as tris (2,3-dibromopropyl) isocyanurate. Can be mentioned. Above all, from the viewpoint of heat resistance and flame retardancy, it is preferable to use a brominated epoxy flame retardant.

As the brominated epoxy flame retardant, a brominated epoxy flame retardant whose molecular terminal is composed of an epoxy group or tribromophenol can be used as a raw material, but the structure of the brominated epoxy flame retardant after melt-kneading is Not particularly limited, when the total number of the constituent units represented by the following chemical formula (1) and the constituent units in which at least a part of the following chemical formula (1) is modified is 100 mol%, 80 mol% or more is represented by the chemical formula (1). It is preferably a constituent unit. The structure of the brominated epoxy flame retardant may change at the molecular end after melt-kneading. For example, the molecular end of the brominated epoxy flame retardant may be substituted with an epoxy group or a hydroxyl group other than tribromophenol, a phosphoric acid group, a phosphonic acid group, or the like, and the molecular end is bonded to the polyester component by an ester group. May be.

Further, a part of the structure other than the molecular terminal of the brominated epoxy flame retardant may be changed. For example, the secondary hydroxyl group of the brominated epoxy flame retardant and the epoxy group may be bonded to form a branched structure, and if the bromine content in the brominated epoxy flame retardant molecule does not change significantly, the above chemical formula ( A part of the bromine of 1) may be eliminated or added.

As the brominated epoxy flame retardant, for example, a polymer type brominated epoxy flame retardant as shown in the following general formula (2) is preferably used. In the following general formula (2), m is 1 to 1000. Examples of the polymer-type brominated epoxy flame retardant as shown in the following general formula (2) include a brominated epoxy flame retardant manufactured by Sakamoto Yakuhin Kogyo Co., Ltd. (trade name “SR-T2MP”). Commercially available products may be used.

The brominated epoxy flame retardant is not particularly limited, but it is preferable that the core portion and / or the sheath portion contains, for example, 5 parts by weight or more and 40 parts by weight or less with respect to 100 parts by weight of the main component resin. For example, from the viewpoint of heat resistance and flame retardancy, 100 parts by weight of one or more polyester resins selected from the group consisting of a polyalkylene terephthalate and a copolymerized polyester mainly composed of polyalkylene terephthalate, and brominated epoxy difficult. 100 parts by weight of a polyamide resin composed of a polyester resin composition containing 5 parts by weight or more and 40 parts by weight or less of a fueling agent, and having a sheath portion mainly composed of at least one selected from the group consisting of nylon 6 and nylon 66, and bromine. It is preferably composed of a polyamide resin composition containing 5 parts by weight or more and 40 parts by weight or less of the copolymerized epoxy flame retardant.

In one or more embodiments of the present invention, a flame retardant aid may be used in combination. The flame retardant aid is not particularly limited, but from the viewpoint of flame retardancy, it is preferable to use, for example, an antimony compound or a composite metal containing antimony. Examples of the antimony compound include antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, potassium antimonate, calcium antimonate and the like. One or more selected from the group consisting of antimony trioxide, antimony pentoxide, and sodium antimonate is more preferable because of the flame retardancy improving effect and the influence on the tactile sensation.

The flame retardant aid is not particularly limited, but it is preferable that the core portion and / or the sheath portion contains, for example, 0.1 part by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the main component resin.

In particular, by incorporating a flame-retardant aid in the polyamide-based resin composition constituting the sheath portion, appropriate surface irregularities are formed on the fiber surface, and in addition to flame retardancy, it has a low-gloss appearance close to that of human hair. It is easy to obtain core-sheath composite fibers for artificial hair.

The core-sheath composite fiber for artificial hair contains various additives such as a heat resistant agent, a stabilizer, a fluorescent agent, an antioxidant, and an antistatic agent, if necessary, within a range that does not impair the effects of the present invention. You may.

The core-sheath composite fiber for artificial hair is for artificial hair by melt-kneading the resin composition of each core-sheath using various general kneaders and then melt-spinning using a core-sheath type composite nozzle. A core-sheath composite fiber can be produced. For example, a polyester-based resin composition obtained by dry-blending each component such as the above-mentioned polyester resin and brominated epoxy flame retardant is melt-kneaded using various general kneaders to form a core component, while the above-mentioned one is described above. A polyamide-based resin composition in which each component such as a polyamide-based resin, a pigment, and a brominated epoxy flame retardant is dry-blended is melt-kneaded using various general kneaders to form a sheath component, and a core-sheath composite spinning nozzle is used. It can be produced by melt-spinning using. Examples of the kneader include a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, a kneader, and the like. Above all, a twin-screw extruder is preferable from the viewpoint of adjusting the kneading degree and easiness of operation.

As a method for producing the fiber of the present invention, a melt spinning method is preferable. For example, in the case of a polyester resin composition, the temperature of the extruder, gear pump, nozzle, etc. is set to 250 ° C. or higher and 300 ° C. or lower, and the polyamide resin composition. In the case of, the temperature of the extruder, gear pump, nozzle, etc. is set to 260 ° C or higher and 320 ° C or lower, and after melt-spinning, the resin is cooled below the glass transition point of each resin at a speed of 30 m / min or more and 5000 m / min or lower. By picking up, spun yarn (undrawn yarn) is obtained.

Specifically, during melt spinning, the polyester resin composition constituting the core portion is supplied by the core extruder extruder of the melt spinning machine, and the polyamide resin composition constituting the sheath portion is the sheath of the melt spinning machine. A spun yarn (undrawn yarn) is obtained by supplying the molten polymer with a core-sheath type composite spinning nozzle (hole) having a predetermined shape and supplying the melted polymer. It is preferable that the spun yarn (undrawn yarn) is heat-stretched, and the stretching is performed by a two-step method in which the spun yarn is once wound and then drawn, and the spun yarn is continuously wound without being wound. It may be carried out by any method of the direct spinning and stretching method of stretching. The thermal stretching is performed by a one-step stretching method or a multi-step stretching method of two or more steps.

As the heating means in the heat stretching, a heating roller, a heat plate, a steam jet device, a hot water tank, etc. can be used, and these can be used in combination as appropriate.

An oil agent such as a fiber treatment agent or a softening agent may be applied to the core-sheath composite fiber for artificial hair to bring the texture and texture closer to human hair. Examples of the fiber treatment agent include silicone-based fiber treatment agents and non-silicone-based fiber treatment agents for improving tactile sensation and combability.

The core-sheath composite fiber for artificial hair may be processed by a gear crimp. As a result, the fibers are gently bent, a natural appearance is obtained, and the adhesion between the fibers is lowered, so that the combability is also improved.
In the processing by the gear crimp, in general, the fiber is passed between two meshed gears in a state where the fiber is heated to the softening temperature or higher, and the shape of the gear is transferred to develop the fiber bending. Further, if necessary, by heat-treating the core-sheath composite fiber for artificial hair at different temperatures in the fiber processing stage, curls having different shapes can be developed.

(Headdress product)
In one or more embodiments of the present invention, the core-sheath composite fiber for artificial hair may be used alone as artificial hair, or may be used in combination with other artificial hair fibers or natural fibers such as human hair and animal hair. May be good. Examples of other artificial hair fibers include acrylic fibers.

In one or more embodiments of the present invention, the core-sheath composite fiber for artificial hair can be used without particular limitation as long as it is a headdress product. For example, it can be used for hair wigs, wigs, weaving, hair extensions, blade hairs, hair accessories, doll hairs and the like.

The headdress product may be composed only of the core-sheath composite fiber for artificial hair of the present invention. Further, the headdress product may be formed by combining the core-sheath composite fiber for artificial hair of the present invention with other fibers for artificial hair or natural fibers such as human hair and animal hair.

Hereinafter, the present invention will be described in more detail based on examples. The present invention is not limited to these examples.

The measurement method and evaluation method used in the examples and comparative examples are as follows.

(Single fiber fineness)
It was measured using a motorcycle blow type fineness measuring device "DENIER COMPUTER type DC-11" (manufactured by Search), and the average value of the measured values of 30 samples was calculated and used as a single fiber fineness.

(Evaluation of fiber cross section)
At room temperature (23 ° C), the fibers are cut to a length of 150 mm, 0.7 g of the cut fibers are bundled, passed through a rubber tube, and then heated at 80 ° C to shrink the fibers. I fixed the bundle so that it would not shift. Then, the tube portion was sliced with a cutter to prepare a fiber bundle for cross-section observation having a length of 5 mm. This fiber bundle was photographed with a laser microscope (manufactured by KEYENCE CORPORATION, "VK-9500") at a magnification of 400 times, and a cross-sectional photograph of the fiber was obtained. The core-sheath ratio was calculated based on the fiber cross-sectional photograph. In addition, 30 fiber cross sections were randomly selected from this fiber cross-section photograph, and the length of the fiber cross-section long axis, the length of the fiber cross-section first short axis, the core cross-section long axis length, and the core cross-section first short axis. The length of the shaft and the distance between the center point of the first short axis of the fiber cross section and the center point of the first short axis of the core cross section were measured. In the core-sheath composite fiber for artificial hair according to the embodiment of the present invention, the length of the long axis of the fiber cross section, the length of the first short axis of the fiber cross section, the length of the long axis of the core, and the first short axis of the cross section of the core. Length, distance between the center point of the first short axis of the fiber cross section and the center point of the first short axis of the core section, the ratio of the long axis of the fiber section to the first short axis of the fiber cross section, and the length of the core section. The value such as the ratio between the shaft and the first short axis of the cross section of the core portion can be indicated by the average value of the measured values of the cross sections of 30 arbitrarily selected fibers.

(Tactile)
A sensory evaluation was performed by a professional beautician, and the evaluation was made according to the following four criteria.
A: Very good tactile sensation equivalent to human hair B: Slightly inferior but good tactile sensation compared to human hair C: Inferior but good tactile sensation compared to human hair D: Greatly inferior bad tactile sensation compared to human hair

(exterior)
A sensory evaluation was performed by a professional beautician, and the evaluation was made according to the following four criteria.
A: Natural appearance equivalent to human hair B: Slightly inferior to human hair but natural appearance C: Inferior to human hair but natural appearance D: Unnatural appearance significantly inferior to human hair

(Curl set property)
At room temperature (23 ° C), 2.8 g of filament is made into 25 cm minoge, wrapped around a φ32 mm pipe, curled at 120 ° C for 60 minutes, aged at room temperature (23 ° C) for 60 minutes, and then curled filament. Fix one end of the pipe and hang it down, and measure the filament length after curl setting. The filament length was used as an index of curl setability and evaluated according to the following four-step criteria.
A: Filament length after curl setting is less than 13 cm B: Filament length after curl set is 13 cm or more and less than 15 cm C: Filament length after curl set is 15 cm or more and less than 17 cm D: Filament length after curl set is 17 cm or more

(Example 1)
Brominated epoxy flame retardant (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., trade name "SR-T2MP") for 100 parts by weight of polyethylene terephthalate pellets (manufactured by East West Chemical Private Limited, East PET product name "A-12", also referred to as PET). 30 parts by weight, sodium antimonate (manufactured by Nippon Seiko Co., Ltd., trade name "SA-A") 3 parts by weight, black pigment master batch (manufactured by Dainichi Seika Kogyo, trade name "PESM22367BLACK (20)", pigment: 20% by weight , Base resin: polyester resin) 3.0 parts by weight, yellow pigment master batch (manufactured by Dainichi Seika Kogyo, trade name "PESM1001YELLOW (20)", pigment: 20% by weight, base resin: polyester resin) 0.6 By weight, 0.2 parts by weight of red pigment master batch (manufactured by Dainichi Seika Kogyo, trade name "PESM3005RED (20)", pigment: 20% by weight, base resin: polyester resin) is added, and after dry blending, biaxial It was supplied to an extruder, melt-kneaded at a barrel set temperature of 280 ° C., and pelletized to obtain a polyester resin composition.

Subsequently, for 100 parts by weight of nylon 6 (manufactured by Unitika, trade name "A1030BRL", also referred to as PA6), 12 parts by weight of brominated epoxy flame retardant (manufactured by Sakamoto Yakuhin Kogyo, trade name "SR-T2MP"), Sodium antimonate (manufactured by Nippon Seiko Co., Ltd., trade name "SA-A") 2 parts by weight, black pigment masterbatch (manufactured by Dainichi Seika Kogyo, trade name "PAM (F) 25005BLACK (20)") 2.0 parts by weight , Yellow pigment masterbatch (manufactured by Dainichi Seika Kogyo, trade name "PAM (F) 28990YELLOW (20)") 0.8 parts by weight, Red pigment masterbatch (manufactured by Dainichi Seika Kogyo, trade name "PAM (F) 28991RED") (20) ”) 0.5 parts by weight was added, and after dry blending, the product was supplied to a twin-screw extruder, melt-kneaded at a barrel set temperature of 260 ° C., and pelletized to obtain a polyamide-based resin composition.

Next, the pellet-shaped polyester resin composition and the polyamide resin composition are supplied to the extruder, respectively, and extruded from a core-sheath type composite spinning nozzle having a nozzle shape shown in Table 1 below at a set temperature of 270 ° C., and 40 to 40 to An undrawn yarn of a core-sheath composite fiber having a polyester-based resin composition as a core portion, a polyamide-based resin composition as a sheath portion, and a core-sheath ratio of 5: 5 by winding at a speed of 200 m / min. Obtained.

The obtained undrawn yarn was drawn using a heat roll at 85 ° C. at a rate of 45 m / min to obtain a triple drawn yarn, and further continuously heated to 200 ° C. using a heat roll at 45 m / min. The polyether oil agent (manufactured by Maruhishi Yuka Kogyo Co., Ltd., trade name "KWC-Q") is wound at the speed of After adhering, the fibers were dried to obtain core-sheath composite fibers having the single fiber fineness shown in Table 1 below and having an eccentricity of 15.6% in the minor axis direction.

(Example 2)
Same as Example 1 except that the core-sheath type composite spinning nozzle having the nozzle shape shown in Table 1 below is used, the eccentricity in the minor axis direction is 12.7%, and the core-sheath ratio is 6: 4. The core-sheath composite fiber was obtained.

(Example 3)
The resin used for the sheath is nylon 66 (manufactured by Toray Industries, Inc., trade name "Amiran CM3001", sometimes referred to as PA66), the barrel set temperature at the time of pelletization is 280 ° C, the nozzle set temperature is 280 ° C, and the short axis. A core-sheath composite fiber was obtained in the same manner as in Example 1 except that the eccentricity in the direction was 15.1% and the core-sheath ratio was 3: 7.

(Example 4)
Using the core-sheath type composite spinning nozzle with the nozzle shape shown in Table 1 below, the resin used for the core is polybutylene terephthalate (manufactured by Mitsubishi Chemical Co., Ltd., trade name "Novaduran 5020", sometimes referred to as PBT) and pellets. Example 1 except that the barrel set temperature at the time of conversion was 260 ° C, the nozzle set temperature was 260 ° C, the eccentricity in the minor axis direction was 6.8%, and the core-sheath ratio was 7: 3 in area ratio. In the same manner, core-sheath composite fibers were obtained.

(Comparative Example 1)
A core-sheath composite spinning nozzle having a nozzle shape shown in Table 1 below was used to obtain a core-sheath composite fiber in the same manner as in Example 1 except that the eccentricity in the minor axis direction was set to 0%.

(Comparative Example 2)
Core-sheath composite fibers were obtained in the same manner as in Example 1 except that the eccentricity in the minor axis direction was 14.1% and the core-sheath ratio was 1: 9.

(Comparative Example 3)
Example 1 and the same as Example 1 except that the core-sheath type composite spinning nozzle having the nozzle shape shown in Table 1 below was used, the eccentricity in the minor axis direction was 2.4%, and the core-sheath ratio was 8: 2. In the same manner, a core-sheath composite fiber was obtained.

(Comparative Example 4)
A core-sheath composite spinning nozzle having a nozzle shape shown in Table 1 below was used to obtain a core-sheath composite fiber in the same manner as in Example 1 except that the eccentricity in the minor axis direction was 9.3%.

The cross-sectional shapes of the fibers of Examples and Comparative Examples were evaluated and observed as described above. In addition, the tactile sensation, appearance, and curl settability of the fibers of Examples and Comparative Examples were evaluated as described above. These results are shown in Table 1.

FIG. 2 is a laser micrograph of a cross section of the fiber of Example 1. As can be seen from FIG. 2, in the core-sheath composite fiber for artificial hair, the fiber has a flat bilobed shape and the core portion has an elliptical cross-sectional shape, and the fiber cross-sectional long axis direction and the core cross-sectional long axis direction are substantially one. It is eccentric in the minor axis direction of the fiber.

FIG. 3 is a laser micrograph of a cross section of the fiber of Comparative Example 1. As shown in FIG. 3, in the core-sheath composite fiber for artificial hair, both the fiber and the core portion have a flat bilobed cross-sectional shape, and the fiber cross-sectional long axis direction and the core portion long axis direction are It is almost the same, but it is not eccentric in the minor axis direction of the fiber.

As can be seen from Table 1, the fibers of Examples 1 to 4 had a tactile sensation and appearance similar to human hair, and had good curl settability.

On the other hand, the fibers of Comparative Example 1 having an eccentricity of 0% and Comparative Example 2 having a high ratio of sheaths had poor curl settability. In the fiber of Comparative Example 3 having a high ratio of the core portion, the core portion was exposed on the fiber surface, the tactile sensation and appearance were very poor, and the fiber could not be molded as a good fiber. The fiber of Comparative Example 4 had an unnatural appearance and a poor tactile sensation because the cross-sectional shape of the fiber and the core portion was round.

The present invention is not particularly limited, but preferably includes at least the following embodiments.
[1] A core-sheath composite fiber for artificial hair including a core and a sheath.
The core portion is composed of a polyester resin composition containing a polyester resin as a main component, and the sheath portion is composed of a polyamide resin composition containing a polyamide resin as a main component.
In the core-sheath composite fiber for artificial hair, the core-sheath ratio is an area ratio of 2: 8 to 7: 3, and both the fiber cross section and the core cross section have a flat cross-sectional shape. , An artificial hair fiber characterized in that the long-axis direction of the cross-section of the fiber and the long-axis direction of the cross-section of the core are substantially the same, and the eccentricity in the short-axis direction of the fiber is 5% or more.
[2] The core-sheath composite fiber for artificial hair according to [1], wherein the core-sheath composite fiber for artificial hair has a flat, multi-leaf-shaped cross-sectional shape.
[3] The core-sheath composite fiber for artificial hair according to [1] or [2], wherein the core portion has an elliptical or flat multi-leaf shape.
[4] In the core-sheath composite fiber for artificial hair, a straight line having the maximum length among straight lines connecting arbitrary two points on the outer periphery of the fiber cross section so as to be parallel to the line symmetry axis and the line symmetry axis. The first fiber cross section, which is a straight line connecting two points having the maximum length when connecting the length of the major axis and any two points on the outer circumference of the fiber section so as to be perpendicular to the long axis of the fiber section. The core-sheath composite fiber for artificial hair according to any one of [1] to [3], wherein the length of the minor axis satisfies the following formula (1).
Length of fiber cross-section major axis / Length of fiber cross-section first minor axis = 1.1 or more and 2.0 or less (1)
[5] In the core-sheath composite fiber for artificial hair, the core which is the maximum length of the straight lines connecting arbitrary two points on the outer periphery of the core portion cross section so as to be parallel to the line symmetry axis and the line symmetry axis. It is a straight line connecting two points that are the maximum length when connecting the length of the long axis of the partial cross section and any two points on the outer circumference of the core cross section so as to be perpendicular to the long axis of the core section. The core-sheath composite fiber for artificial hair according to any one of [1] to [4], wherein the length of the first minor axis having a cross section of the core satisfies the following formula (2).
Core cross-section long axis length / core cross-section first minor axis length = 1.3 or more and 2.0 or less (2)
[6] Any of [1] to [5], wherein the polyester-based resin composition contains one or more polyester-based resins selected from the group consisting of polyalkylene terephthalates and copolymerized polyesters mainly composed of polyalkylene terephthalates. Core-sheath composite fiber for artificial hair described in Crab.
[7] The artificial hair according to any one of [1] to [6], wherein the polyamide-based resin composition contains a polyamide-based resin mainly composed of at least one selected from the group consisting of nylon 6 and nylon 66. Core sheath composite fiber.
[8] A headdress product comprising the core-sheath composite fiber for artificial hair according to any one of [1] to [7].
[9] The headdress product according to [8], wherein the headdress product is one selected from the group consisting of hair wigs, wigs, weaving, hair extensions, blade hairs, hair accessories and doll hairs.
[10] The method for producing a core-sheath composite fiber for artificial hair according to any one of [1] to [7].
A step of melt-spinning a polyester-based resin composition and a polyamide-based resin composition using a core-sheath composite nozzle is included.
The cross-sectional shape of the core-sheath composite fiber for artificial hair and the core portion shall be flat, the fiber cross-sectional long axis direction and the core portion long axis direction shall be substantially the same, and the eccentricity in the minor axis direction of the fiber shall be 5% or more. A method for producing a core-sheath composite fiber for artificial hair.

1 Core sheath composite fiber for artificial hair (cross section)
10 Sheath 11 Fiber cross-section long axis 12 Fiber cross-section 1st short axis 13 Fiber cross-section 1st short axis center point 20 Core 21 Core cross-section long axis 22 Core cross-section 1st short axis 23 Core section 1st short axis Center point of

Claims

A core-sheath composite fiber for artificial hair including a core and a sheath.
The core portion is composed of a polyester resin composition containing a polyester resin, and the sheath portion is composed of a polyamide resin composition containing a polyamide resin.
In the core-sheath composite fiber for artificial hair, the core-sheath ratio is an area ratio of 2: 8 to 7: 3, and both the fiber cross section and the core cross section have a flat cross-sectional shape. , An artificial hair fiber characterized in that the long-axis direction of the cross-section of the fiber and the long-axis direction of the cross-section of the core are substantially the same, and the eccentricity in the short-axis direction of the fiber is 5% or more.
The core-sheath composite fiber for artificial hair according to claim 1, wherein the core-sheath composite fiber for artificial hair has a flat, multi-leaf-shaped cross-sectional shape.
The core-sheath composite fiber for artificial hair according to claim 1 or 2, wherein the core portion has an elliptical or flat multi-leaf shape.
In the core-sheath composite fiber for artificial hair, the long axis of the fiber cross section, which is the longest straight line connecting arbitrary two points on the outer periphery of the fiber cross section so as to be parallel to the line symmetry axis and the line symmetry axis. The first minor axis of the fiber cross section, which is a straight line connecting the length and any two points on the outer circumference of the fiber section so as to be perpendicular to the long axis of the fiber cross section, which is the maximum length. The core-sheath composite fiber for artificial hair according to any one of claims 1 to 3, wherein the length satisfies the following formula (1).
Length of fiber cross-section major axis / Length of fiber cross-section first minor axis = 1.1 or more and 2.0 or less (1)
In the core-sheath composite fiber for artificial hair, the core cross-sectional length is the longest straight line connecting arbitrary two points on the outer periphery of the core cross section so as to be parallel to the line symmetry axis and the line symmetry axis. A core section that is a straight line connecting two points that have the maximum length when connecting the length of the shaft and any two points on the outer circumference of the core section so as to be perpendicular to the core section long axis. The core-sheath composite fiber for artificial hair according to any one of claims 1 to 4, wherein the length of the first minor axis satisfies the following formula (2).
Core cross-section long axis length / core cross-section first minor axis length = 1.3 or more and 2.0 or less (2)
The artificial according to any one of claims 1 to 5, wherein the polyester-based resin composition contains one or more polyester-based resins selected from the group consisting of polyalkylene terephthalates and copolymerized polyesters mainly composed of polyalkylene terephthalates. Core-sheath composite fiber for hair.
The core-sheath composite fiber for artificial hair according to any one of claims 1 to 6, wherein the polyamide-based resin composition contains a polyamide-based resin mainly composed of at least one selected from the group consisting of nylon 6 and nylon 66. ..
A headdress product comprising the core-sheath composite fiber for artificial hair according to any one of claims 1 to 7.
The headdress product according to claim 8, wherein the headdress product is one selected from the group consisting of hair wigs, wigs, weaving, hair extensions, blade hairs, hair accessories and doll hairs.
The method for producing a core-sheath composite fiber for artificial hair according to any one of claims 1 to 7.
A step of melt-spinning a polyester-based resin composition and a polyamide-based resin composition using a core-sheath composite nozzle is included.
The cross-sectional shape of the core-sheath composite fiber for artificial hair and the core is flat, the long-axis direction of the fiber cross-section and the long-axis direction of the core are substantially the same, and the eccentricity of the fiber in the short-axis direction is 5% or more. A method for producing a core-sheath composite fiber for artificial hair.