JP2016211094A - Fiber for artificial hair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fiber for artificial hair, easily producible, and having surface gloss and texture similar to human hair.SOLUTION: The fiber for artificial hair has single fiber fineness of at least 20dtex and mainly comprises an aromatic polyester resin, the fiber containing 0.1 to 5 mass% of polystyrene polymers and having an irregular surface. It is preferable that the aromatic polyester resin is a polyethylene terephthalate resin and contains a pigment, and that the polystyrene polymer has a glass transition temperature that is 5°C higher than the glass transition temperature of the aromatic polyester resin. The method for manufacturing the fiber comprises melt spinning the aromatic polyester resin containing 0.1 to 5 mass% of the polystyrene polymers so as to achieve a single fiber fineness of 20dtex.SELECTED DRAWING: None

Description

  The present invention relates to a fiber for artificial hair, and more particularly to a fiber for artificial hair made of a polyester resin having excellent durability and appearance.

As synthetic hair materials, various synthetic fibers are used as materials for wigs, hair wigs, extensions, hair bands, and the like. Among them, polyvinyl chloride fibers have been widely used, but there is a problem that strength and durability against a heating set are low.
Therefore, recently, the use of synthetic fibers such as polyester having excellent basic properties such as tensile strength and heat resistance has been widely studied. However, such synthetic fibers have basically a flat fiber surface shape immediately after spinning, and are often inferior in surface appearance and texture.

  Therefore, as a surface treatment technique for polyester-based artificial hair fibers, for example, Patent Document 1 discloses a method in which polyester fibers containing fine particles such as silicon oxide are treated with an alkaline aqueous solution to give specific fine irregularities to the fiber surface. Has been proposed. Although post-processing such as alkali weight loss treatment was an excellent method for obtaining luster and touch similar to human hair, environmental problems such as the generation of waste alkaline solution and final products As the number of processes increases, there is a problem that the cost of the product is increased and the lead time is increased.

  On the other hand, as a gloss adjusting means that does not require such post-processing, for example, Patent Document 2 discloses a method of adjusting the gloss of a fiber by adding organic or inorganic fine particles to the fiber. However, in order to obtain a gloss equivalent to that of human hair, it is necessary to add a considerable amount of fine particles, and it has been difficult to uniformly knead the fibers. Patent Documents 3 and 4 disclose artificial hair fibers containing polyarylate, aromatic polyamide or the like in polyester, but are still insufficient in terms of balance between physical properties and texture.

JP 63-12716 A JP-A-5-86505 JP 2004-3089 A JP 2007-297737 A

  The present invention was made based on the above background, and its object is to provide a fiber for artificial hair that has a surface gloss and texture close to human hair, while being easily manufactured. And

The fiber for artificial hair of the present invention is a fiber having a single fiber fineness mainly composed of an aromatic polyester resin of 20 dtex or more, containing 0.1 to 5% by mass of a polystyrene-based polymer, and the surface of the fiber is uneven. Is present.
Furthermore, the aromatic polyester resin is a polyethylene terephthalate resin, the aromatic polyester resin contains a pigment, and the glass transition temperature of the polystyrene-based polymer is 5 higher than the glass transition temperature of the aromatic polyester resin. It is preferable that the temperature is higher than the temperature.
Further, the method for producing a fiber for artificial hair of the present invention is characterized in that an aromatic polyester resin containing 0.1 to 5% by mass of a polystyrene polymer is melt-spun and the single fiber fineness is 20 dtex or more.

  ADVANTAGE OF THE INVENTION According to this invention, the fiber for artificial hair which has the surface glossiness and texture close | similar to human hair, while being able to manufacture easily is provided.

Hereinafter, modes for carrying out the present invention will be described.
The fiber for artificial hair of the present invention is a fiber having a single fiber fineness mainly composed of an aromatic polyester resin of 20 dtex or more, containing 0.1 to 5% by mass of a polystyrene-based polymer, and the surface of the fiber is uneven. Is the existing fiber.

  Here, the aromatic polyester resin which is the main constituent of the fiber for artificial hair of the present invention is terephthalic acid or 2,6-naphthalenedicarboxylic acid as a main difunctional carboxylic acid, ethylene glycol, 1,3-propane. An aromatic polyester having diol or 1,4-butanediol as the main glycol component, specifically, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate is preferred. The aromatic polyester resin is preferably a polyethylene terephthalate resin from the balance between high productivity and performance such as texture.

  The polyester as the main component is within a range that does not impair the object of the present invention, specifically, 15 mol% or less, preferably 10 mol% or less, particularly preferably 5 mol% or less, based on the total acid component. The copolymerization component may be copolymerized. As the copolymer component, various acid components and various diol components are preferably used. Among these, phosphorus compounds such as phosphoric acid and phosphonic acid are preferable from the viewpoint of flame retardancy. Further, as long as the amount is small, a trifunctional compound such as trimesic acid, trimellitic acid, boric acid, glycerin, trimethylolpropane and the like may be copolymerized.

The intrinsic viscosity of this aromatic polyester resin is preferably 0.40 to 0.70 dl / g, more preferably 0.45 to 0.60 dl / g. When the intrinsic viscosity is too small, the strength of artificial hair tends to be insufficient. On the other hand, if it is too large, the bending rigidity of the resulting fiber increases, and the texture tends to dissociate from human hair.
And the fiber for artificial hair of this invention is a fiber which mainly contains the above aromatic polyester resins, Comprising: It is a fiber containing 0.1-5 mass% of polystyrene-type polymers. Furthermore, it is preferable that the surface of the fiber has irregularities, and the irregularities are minute protrusions.

  The polystyrene polymer contained in the fiber for artificial hair of the present invention is a polymer comprising a styrene compound as a monomer, and is a polymer of an unsubstituted styrene or a monomer having a phenyl group as a substituent, or those It is preferable that it is a copolymer. Further, the polystyrene-based polymer is preferably a crystalline polystyrene-based polymer having a high degree of stereoregularity as a monomer arrangement rather than a general amorphous polymer.

  There are generally three types of stereoregularity of monomers. When the molecular chain of a polymer is stretched in a straight line, all of the side chains (phenyl groups) are on the same side of the molecular chain. Can be classified into “syndiotactic” in which both are completely alternated on both sides of the molecular chain, and “atactic” in which side chains are randomly arranged on both sides of the molecular chain. The polystyrene polymer used in the present invention is preferably a crystalline isotactic or syndiotactic polymer rather than a general amorphous atactic polymer. Further, a syndiotactic polymer having a high crystallization rate is particularly preferable. By using syndiotactic polystyrene as the polystyrene-based polymer, even if a small amount of polystyrene-based polymer is added, it is possible to greatly influence the fiber form in the polymer melt spinning process.

  Further, the polystyrene-based polymer is a crystalline polymer having a melting point, and the melting point is preferably higher than the melting point of the aromatic polyester resin as the main component. Therefore, the higher the stereoregularity of the polystyrene polymer, the better. Specifically, the melting point difference is preferably 3 ° C. or higher, particularly 5 ° C. or higher. The melting point of the polystyrene polymer is preferably 260 ° C. or higher, and particularly preferably in the range of 265 ° C. to 300 ° C. By using a crystalline polymer having such a high melting point, the heat resistance and shape stability of the aromatic polyester resin as a base are not impaired, so that the texture and surface gloss change even when used at high temperatures. It becomes possible to obtain few artificial hair fibers.

  Such a polystyrene-based polymer has a glass transition temperature higher than that of the main component aromatic polyester resin, and is rapidly solidified in the cooling step after being melted. Therefore, the presence of a small amount of 0.1 to 5% by mass of a polystyrene-based polymer greatly affects the fiber morphology in the polymer processing step. Specifically, the glass transition temperature of the polystyrene-based polymer contained in the present invention is preferably higher than the glass transition temperature of the aromatic polyester resin, and more preferably 5 ° C. or higher. In particular, the glass transition temperature of the polystyrene-based polymer is preferably 10 to 30 ° C. higher than the glass transition temperature of the aromatic polyester resin. The glass transition temperature of a specific polystyrene polymer is preferably in the range of 90 to 120 ° C.

  Further, the concentration of the polystyrene-based polymer used in the present invention in the fiber resin needs to be in the range of 0.1 to 5% by mass, and more preferably in the range of 0.5 to 3% by mass. Is preferred. When the abundance is less than 0.1% by mass, the unevenness formed on the fiber surface is reduced, and the effect of suppressing surface reflection cannot be sufficiently obtained. On the other hand, if the abundance exceeds 5%, the yarn forming property is lowered and the color developing property is lowered. This is because the polystyrene polymer itself has no dyeability. In the present invention, by adjusting the concentration of the polystyrene-based polymer to the above range, characteristics such as gloss, texture and combability required for artificial hair fibers can be satisfied at a high level.

  Further, such an effect of adding a polystyrene-based polymer becomes more prominent when the fiber diameter after melt spinning is larger. If it is too thin, not only will the change in the surface form of the fiber become too great, but the fiber will break in the production process and fibers with satisfactory physical properties will not be obtained. The fiber for artificial hair, which is a thick fiber having a single fiber fineness of 20 dtex or more according to the present invention, has a natural luster close to human hair by an aromatic polyester resin as a main component and a polystyrene-based polymer added in a small amount. It has a texture.

  The fiber for artificial hair of the present invention needs to be a thick fiber having a single fiber fineness of 20 dtex or more, more preferably in the range of 20 to 110 dtex, and particularly in the range of 30 to 90 dtex. It is preferable. With such a thick fiber diameter, the effect of adding a small amount of polystyrene-based polymer becomes clearer, and the appearance and texture of natural hair can be realized. It is also preferable to mix fibers of two or more single yarn fineness depending on the desired texture and gloss. For example, it is preferable to mix fibers of less than 50 dtex and 50 dtex or more, and more specifically, it is also a preferable aspect to mix two types of single yarn fine fibers of 30 dtex and 70 dtex and mix several types of fibers.

  Further, the aromatic polyester resin which is the main component constituting the fiber of the present invention preferably contains a known ultraviolet absorber for the purpose of preventing discoloration of the artificial hair being used. As an ultraviolet absorber preferably used, for example, benzotriazole such as 2,2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol UV absorbers, 2-hydroxy-4- (methacryloyloxyethoxy) benzophenone 30-50 mol% and random copolymers of methyl methacrylate 70-30 mol%, benzophenone UV absorbers such as 2,4-dihydroxybenzophenone, Examples thereof include iron oxide fine particles. These have good heat resistance when added to and mixed with polyester in a molten state, and high light resistance can be obtained. Further, when a high molecular weight random copolymer is used, there is little bleeding out from the polyester fiber, and stable light resistance can be obtained. Further, two or more of these various ultraviolet absorbers may be used in combination.

Moreover, you may contain well-known organic or inorganic flame retardants, such as phosphorus type | system | group, halogen type | system | group, and antimony trioxide, in aromatic polyester resin. While using artificial hair fiber, it is possible to protect the human body from dangers due to fire or the like. Furthermore, it is preferable to modify the aromatic polyester resin itself or to blend an antistatic agent in the aromatic polyester resin. It becomes possible to prevent clinging and entanglement due to charging of the fibers, or adhesion of dust.
Furthermore, the fiber for artificial hair of the present invention is not limited to a round cross-section as its cross-sectional shape, and a flat cross-section, a spectacle-type cross-section, a hollow cross-section, etc. can be appropriately selected according to the application and purpose.

  In such an artificial hair fiber of the present invention, it is also preferable to dye it last, or to make it an original fiber in which various pigments such as carbon black are previously contained in an aromatic polyester resin. When a pigment is added, the dye used for dyeing can be saved, or it is not necessary to carry out dyeing depending on the use, which is particularly effective in terms of cost reduction and lead time reduction. The artificial hair fiber of the present invention can be optimally used for various uses for coloring in various colors.

Moreover, the fiber for artificial hair of this invention melt-spins the aromatic polyester resin containing 0.1-5 mass% of another polystyrene-type polymer which is this invention, and makes single fiber fineness 20 dtex or more. It can be obtained by a method for producing a fiber for artificial hair.
Here, the aromatic polyester resin and polystyrene polymer described above can be used as the aromatic polyester resin and polystyrene polymer which are the main constituents of the fiber for artificial hair of the present invention.

  As a specific example, as a specific aromatic polyester resin, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate is preferable. The aromatic polyester resin is preferably a polyethylene terephthalate resin from the balance between high productivity and performance such as texture. Moreover, the copolymerization component may be copolymerized as long as the object of the present invention is not impaired. The intrinsic viscosity of the aromatic polyester resin is preferably 0.40 to 0.70 dl / g, and more preferably 0.45 to 0.60 dl / g. When the intrinsic viscosity is too small, the strength of artificial hair tends to be insufficient. On the other hand, if it is too large, the bending rigidity of the resulting fiber increases, and the texture tends to dissociate from human hair.

  And the method for producing the fiber for artificial hair of the present invention is an aromatic polyester resin as described above, wherein an aromatic polyester resin containing 0.1 to 5% by mass of a polystyrene polymer is melt-spun, In this manufacturing method, the fiber fineness is 20 dtex or more. Furthermore, it is preferable that the fiber surface after melt spinning has irregularities, and in particular, has fine protrusions.

  The polystyrene-type polymer mentioned above can be used for the polystyrene-type polymer contained by this invention. Again, the glass transition temperature of the polystyrene polymer is preferably higher than the glass transition temperature of the aromatic polyester resin, more preferably 5 ° C. or higher. In particular, the glass transition temperature of the polystyrene polymer is preferably 10 to 30 ° C. higher than the glass transition temperature of the aromatic polyester resin. A more specific glass transition temperature of the polystyrene-based polymer is preferably in the range of 90 to 120 ° C.

  The polystyrene polymer is a polymer composed of a styrene compound as a monomer, and is preferably an unsubstituted styrene, a polymer of a monomer having a substituent on a phenyl group, or a copolymer thereof. Further, the polystyrene-based polymer is preferably a crystalline polystyrene-based polymer having a high degree of stereoregularity as a monomer arrangement rather than a general amorphous polymer.

  Furthermore, the polystyrene-based polymer used in the production method of the present invention is preferably a crystalline isotactic or syndiotactic polymer rather than a general amorphous atactic polymer. Further, a syndiotactic polymer having a high crystallization rate is particularly preferable. By using syndiotactic polystyrene as the polystyrene-based polymer, even if a small amount of polystyrene-based polymer is added, it is possible to greatly influence the fiber form in the polymer melt spinning process.

  Further, the polystyrene-based polymer is a crystalline polymer having a melting point, and the melting point is preferably higher than the melting point of the aromatic polyester resin as the main component. Therefore, the higher the stereoregularity of the polystyrene polymer, the better. Specifically, the melting point difference is preferably 3 ° C. or higher, particularly 5 ° C. or higher. The melting point of the polystyrene polymer is preferably 260 ° C. or higher, and particularly preferably in the range of 265 ° C. to 300 ° C. By using such a crystalline polymer having a high melting point, it becomes possible to obtain a fiber for artificial hair with little change in texture and surface gloss even when used at a high temperature by the production method of the present invention.

  Further, the concentration of the polystyrene-based polymer used in the production method of the present invention in the molten resin needs to be in the range of 0.1 to 5% by mass, and more preferably in the range of 0.5 to 3% by mass. It is preferable that If the abundance is less than 0.1% by mass, the number of protrusions formed on the fiber surface is reduced, and a sufficient effect of suppressing surface reflection cannot be obtained. On the other hand, if the abundance exceeds 5%, the yarn forming property is lowered and the color developing property is lowered. In the production method of the present invention, by adjusting the concentration of the polystyrene-based polymer at the time of melt spinning to the above range, the properties such as gloss, texture, and combability required for artificial hair fibers are satisfied at a high level. I was able to.

  As a method of mixing and dispersing such a polystyrene-based polymer in a polyester resin, the pellets of both polymers are blended in advance in a predetermined weight ratio with a batch mixer such as a Nauta mixer or a double cone blender, A method of melt-kneading with a melt extruder (extruder), a method of supplying each pellet continuously to an extruder with a separate lightweight machine so as to have a predetermined mixing ratio, and a melt-kneading method, or separately melting each polymer A method of kneading at the above-mentioned weight ratio through a multistage static mixer can be used, and these components can be melt-kneaded. As the extruder, a biaxial extruder is more preferable than a monoaxial extruder because of excellent kneading properties. In particular, when each component is supplied from a separate weighing machine, it is preferable to use a biaxial extruder.

  The pellets of the aromatic polyester resin are preferably dried by vacuum drying, heated nitrogen or dehumidified air in order to suppress a decrease in molecular weight due to hydrolysis. It is also preferable to install a degassing device (vent device) in the extruder and supply non-dried pellets. At this time, as a method for drying the pellets, a method of drying the mixed pellets or a method of mixing the separately dried pellets after drying may be used.

  And the manufacturing method of the fiber for artificial hair of this invention melt-spins resin which contains the polystyrene-type polymer in the above aromatic polyester resins. The molten resin discharged from the die is preferably cooled under the spinneret. Although the cooling method is not particularly limited, a method of applying cooling air to the spun yarn and a method of cooling the yarn by passing it through a cooling tank containing cooling water can be preferably exemplified.

  It is preferable to perform stretching and heat treatment without subsequent winding or winding. The speed at the time of winding is preferably 30 to 2000 m / min, and then the draw ratio is preferably 2.0 to 6.0 times. As a heating means at the time of stretching, a hot water bath, a heating roller, a heat plate, or the like can be used, and these can be used in combination as appropriate.

  The stretched yarn is preferably subjected to heat treatment in order to improve thermal dimensional stability. The heat treatment is preferably a tension heat treatment. The obtained fiber can also be used as a fiber for artificial hair as it is, and it is also preferable to improve the antistatic property, tactile sensation and the like by appropriately applying a treatment agent such as an alkyl phosphate potassium salt or a silicone surfactant.

  In the method for producing polyester fiber for artificial hair according to the present invention, an aromatic polyester resin containing a small amount of a polystyrene-based polymer is once melted, and the melt spinning as described above is performed by discharging the melted resin from a die. The polystyrene polymer at this time has a glass transition temperature higher than that of the main component aromatic polyester resin. Therefore, in the production method of the present invention, the polystyrene-based polymer is first solidified in the molten aromatic polyester resin. In this way, the polystyrene-based polymer is first solidified in the molten aromatic polyester resin, so that the relaxation of the orientation of the aromatic polyester resin as the main component is promoted. As a result, the fiber for artificial hair finally obtained by the production method of the present invention has a low orientation and a softer texture. Further, since a small amount of 0.1 to 5% by mass of a polystyrene-based polymer is added and melt-spun, irregularities and minute protrusions are generated on the surface, and a refractive difference of the polymer occurs on the fiber surface. By scattering and irregular reflection of light on the surface, it becomes a natural fiber for artificial hair having a gloss that is very similar to human hair.

  The effect of adding such a polystyrene-based polymer in the present invention becomes more prominent when the fiber diameter after melt spinning is larger. If it is too thin, not only will the surface morphology of the fiber change too much, but the fiber will break in the production process and fibers with satisfactory physical properties will not be obtained. In the production method of the present invention, it is necessary to use a fiber for artificial hair which is a thick fiber having a single fiber fineness of 20 dtex or more, and an aromatic polyester resin as a main component and a polystyrene polymer added in a small amount, It has a natural luster and texture similar to human hair. Furthermore, the single fiber fineness is preferably in the range of 20 to 110 dtex, particularly preferably in the range of 30 to 90 dtex. By using such a thick fiber diameter, the effect of adding a small amount of polystyrene-based polymer becomes clearer, and the appearance and texture of natural hair can be realized.

  Furthermore, in the method for producing a fiber for artificial hair of the present invention, the cross-sectional shape is not limited to a round cross section, and a flat cross section, a glasses-type cross section, a hollow cross section, etc. can be appropriately selected according to the application and purpose. .

  And in the manufacturing method of the fiber for artificial hair of this invention, it is also preferable to make it dyed last, and to make it the original fiber which previously contained various pigments, such as carbon black, in aromatic polyester resin. Furthermore, it is preferable to dye a dyed fiber after adding a pigment to make the original fiber. By adding the pigment, the dye at the time of dyeing can be saved, or it is not necessary to carry out dyeing depending on the use, which is effective in terms of cost reduction and lead time reduction. The fiber obtained by the manufacturing method of the fiber for artificial hair of this invention can be optimally used regarding the various uses colored to such various colors.

  The artificial hair fiber of the present invention obtained by such a production method has a surface gloss and texture close to human hair even with the fiber just after melt spinning. It can be used as artificial hair without post-processing treatment such as alkali weight loss treatment that is usually performed well. However, further post-processing is not excluded, and post-processing that generates another new added value such as dyeing is one of preferred embodiments. Disperse dyes can also be used as the dye, but from the viewpoint of preventing discoloration of artificial hair during use, it is preferable to use a dye having a light fastness of 5th or higher. As a dyeing method, a method using a known dyeing carrier agent may be used, but it is more preferable to use a high-pressure dyeing method which does not require a dyeing carrier agent. As described above, it is also preferable to add various pigments such as carbon black to the artificial hair fiber of the present invention.

  Next, although the Example and comparative example of this invention are explained in full detail, this invention is not limited by these. In addition, the measurement item in an Example was measured with the following method.

(Intrinsic viscosity)
0.12 g of a polymer sample was dissolved in 10 mL of tetrachloroethane / phenol (volume ratio 1/1), and the reduced viscosity (mL / g) at 35 ° C. was measured.

(Single fiber fineness)
Measured by the method described in JIS L 1015: 2005 8.5.1 Method A.

(Evaluation of surface gloss of artificial hair fibers)
Visually confirmed under natural light, a product having a surface gloss close to that of human hair was judged as good (◯), and a product with a large surface reflection and glare was judged as poor (x).

(Evaluation of texture of artificial hair fibers)
The fiber sample bundle was directly touched to evaluate the feel and determine the texture. Those having a tactile sensation close to human hair were judged to be excellent (）), those having tactile sensation were good (○), and those having a smooth, hard and tactile sensation were judged to be impossible (×).

[Example 1]
90% by mass of an aromatic polyester chip having an intrinsic viscosity of 0.62 (polyethylene terephthalate chip, glass transition temperature Tg 80 ° C., melting point Tm 264 ° C.), 6% by mass of an aromatic polyester masterbatch containing 30% by mass of carbon black, polystyrene series 4% by mass of a polymer (syndiotactic polystyrene, glass transition temperature Tg 100 ° C., melting point Tm 270 ° C.) was mixed with a tumbler, and then dried at 160 ° C. for 8 hours under vacuum. Spinning the mixed chip at 290 ° C. using an extruder-type kneader, a metering gear pump, and a spinning machine having a filtration layer made of 60 mesh metal sand and 300 mesh wire netting, and having 4 holes of perfect circular shape. The melt was discharged from the die, and air cooled with a cooling air of 27 ° C. at a position 32 mm below the spinneret, and then wound up at 630 m / min to obtain a spinning raw yarn. Next, the film was stretched 2.94 times in warm water at 70 ° C., further subjected to tension heat treatment at 195 ° C., and then a surfactant mainly composed of alkyl phosphate potassium salt was applied to give 1000 dtex / 16 fil (single fiber fineness 62. 5 dtex) as a drawn yarn.
Table 1 shows the results of evaluating the surface gloss and texture of the obtained fibers.

[Example 2]
The yarn was produced under the same conditions as in Example 1 except that an aromatic polyester chip (polyethylene terephthalate chip) having an intrinsic viscosity of 0.55 was used instead of the aromatic polyester chip having an intrinsic viscosity of 0.62. The results of evaluating the surface gloss and texture of the obtained fibers are also shown in Table 1.

[Comparative Example 1]
Yarn production was performed using an aromatic polyester chip (polyethylene terephthalate chip) having an intrinsic viscosity of 0.62 in the same manner as in Example 1 except that the polystyrene-based polymer and carbon black were not added. The results of evaluating the surface gloss and texture of the obtained fibers are also shown in Table 1.

[Comparative Example 2]
In Example 1, instead of 4% by mass of the polystyrene-based polymer, yarn was produced under the same conditions as in Example 1 except that 4% by mass of poly-L-lactic acid (glass transition temperature Tg 60 ° C., melting point Tm 180 ° C.) was used. The results of evaluating the surface gloss and texture of the obtained fibers are also shown in Table 1.

[Comparative Example 3]
In Example 1, yarns were produced under the same conditions as in Example 1 except that the addition concentration of 4% by mass of the polystyrene-based polymer was 8% by mass. However, yarn breakage occurred during spinning, and satisfactory yarn production was possible. There wasn't.

Claims (5)

  An artificial fiber characterized in that the single fiber fineness mainly composed of an aromatic polyester resin is 20 dtex or more, contains 0.1 to 5% by mass of a polystyrene-based polymer, and has irregularities on the surface of the fiber. Fiber for hair.   The artificial hair fiber according to claim 1, wherein the aromatic polyester resin is a polyethylene terephthalate resin.   The fiber for artificial hair according to claim 1 or 2, wherein the aromatic polyester resin contains a pigment.   The fiber for artificial hair according to any one of claims 1 to 3, wherein the glass transition temperature of the polystyrene-based polymer is 5 ° C or higher than the glass transition temperature of the aromatic polyester resin.   A method for producing a fiber for artificial hair, characterized in that an aromatic polyester resin containing 0.1 to 5% by mass of a polystyrene-based polymer is melt-spun and the single fiber fineness is 20 dtex or more.