JP6648974B2 - Cellulosic fiber and artificial hair comprising the same - Google Patents

Description

  The present invention relates to cellulosic fibers. More specifically, the present invention relates to a cellulosic fiber having a texture close to that of human hair, excellent in deep color, matting, and combability, and suitable for use in artificial hair.

  BACKGROUND ART Cellulose-based materials are the most mass-produced biomass on the earth, and have recently received a great deal of attention as biodegradable materials under natural environments. In addition, since a cellulosic material has a low refractive index, when it is made into a fiber, it has an advantage of being excellent in clear color development. Furthermore, since the cellulosic material has a high hydrophilicity, when it is made into a fiber, it also has an advantage of being excellent in moisture absorption / release properties.

  BACKGROUND ART Cellulose fibers such as viscose rayon and cupra, and cellulose ester fibers such as acetate and triacetate are widely used mainly for clothing, taking advantage of their excellent features such as vivid color development and moisture absorption / release properties. Generally, cellulose fibers are produced by a wet spinning method in which cellulose is dissolved in a solvent such as a copper ammonia solution, and then spinning is performed in a solution called a coagulation bath while removing the solvent. In addition, cellulose ester fibers are produced by a dry spinning method in which a cellulose ester such as cellulose acetate is dissolved in an organic solvent such as acetone or a methylene chloride / alcohol mixture, and then the solvent is evaporated while spinning. . When these production methods are used, it is difficult to obtain a cellulose fiber or a cellulose ester fiber having a large single-filament fineness because it is necessary to remove the solvent from the fiber surface or the inside of the fiber.

  As means for solving the above problems, a technique for obtaining cellulose ester fibers by melt spinning has been proposed. For example, according to Patent Document 1, it has become possible to obtain cellulose ester fibers having a large single-filament fineness by melt spinning of a cellulose ester composition having thermoplasticity. Further, the obtained cellulose ester fiber has a texture such as flexibility, moisture absorption / desorption property, and coloring property, and thus can be suitably used as a fiber structure such as artificial hair.

  Monofilaments made of synthetic fiber materials such as polyester, polyamide, acrylic and polyolefin are widely used as artificial hair such as wigs and hair wigs, clothing materials such as woven and knitted fabrics, and interior materials such as curtains and laces. When used as artificial hair such as wigs and hair wigs, it is necessary to combine textures such as flexibility, moisture absorption and desorption, and coloring, but as a general fiber property, high elasticity lacks flexibility, If the hydrophilicity is low, there is a defect that the film lacks moisture absorption / desorption properties, and if the refractive index is high, the film lacks coloration. Synthetic fiber materials such as polyester, polyamide, acrylic, and polyolefin have any of the above-mentioned disadvantages. Therefore, when used together with human hair as artificial hair, the entire hair may be different due to the difference in texture from human hair. There was a problem that a sense of incongruity arises.

  As means for remedying these drawbacks, for example, according to Patent Document 2, polyester fibers containing fine particles such as silicon oxide are treated with an aqueous alkaline solution to form polyester for artificial hair in which fine irregularities are formed on the fiber surface. Fibers have been proposed.

JP 2009-228159 A JP-A-63-12716

  However, although the cellulose ester fiber obtained by the method described in Patent Document 1 has a texture such as flexibility, moisture absorption / release properties, and coloring properties, the surface of the fiber does not have irregularities, so the surface gloss is strong and the artificialness is high. It was not endurable for use as hair.

  In addition, the polyester fiber obtained by the method described in Patent Document 2 had insufficient matting because the surface irregularities were too fine and uniform. For this reason, when light is received from an oblique direction, strong light reflection is recognized, and its use as artificial hair is restricted. Further, since the polyester fiber easily generates static electricity, the combability is not satisfactory.

  As described above, according to the conventional technique, it is not possible to obtain a fiber which has a texture such as flexibility, moisture absorption / release properties, and color developing properties, and has good matting properties and combability, which is suitable for artificial hair use. The object of the present invention is to solve the above-mentioned problems of the prior art, have a texture close to that of human hair, have excellent deep color, matte, and combability, and are suitable for artificial hair. To provide fibers.

The object of the present invention is that the average fiber diameter is 25 to 500 μm, the average number of concave portions per unit area on the fiber surface is 0.001 to 0.5 / μm ² , and the average diameter of the concave portions is 0. The problem can be solved by a cellulosic fiber characterized by having a thickness of 0.5 to 30 μm.

  Further, the cellulosic fiber has a core-in-sheath composite structure containing cellulose and a cellulose ester in which at least a part of the acyl group has 3 to 18 carbon atoms, and the core has the cellulose ester as a main component and a sheath portion. Preferably, cellulose is a main component, and the cellulose ester is preferably cellulose acetate propionate and / or cellulose acetate butyrate.

  Further, the above-mentioned cellulosic fiber is preferably a monofilament, and can be suitably used for artificial hair characterized by using the above-mentioned cellulosic fiber at least in part.

  According to the present invention, it is possible to provide a cellulosic fiber having a texture close to that of human hair, and excellent in deep color, matting, and combability, and can be particularly preferably used for artificial hair. In addition, it can be suitably used as an auxiliary material for clothing such as a woven or knitted fabric for clothing, a core of a collar or a sleeve, and a living material such as a curtain.

9 is a photograph as a drawing showing the fiber surface of the cellulosic fiber produced in Example 4. 9 is a photograph as a substitute of a drawing showing a fiber surface of a cellulosic fiber produced in Comparative Example 2. 13 is a drawing-substituting photograph showing the fiber surface of the cellulosic fiber produced in Comparative Example 5.

The cellulosic fiber of the present invention has an average fiber diameter of 25 to 500 μm, an average number of concave portions per unit area on the fiber surface of 0.001 to 0.5 / μm ² , and an average diameter of the concave portions of 0 to 0. 0.5 to 30 μm. Cellulose-based fibers are excellent in texture, such as flexibility, moisture absorption / release properties, and coloring. When the average number of concave portions per unit area on the fiber surface of the cellulosic fiber is 0.001 to 0.5 / μm ² , and the average diameter of the concave portions is 0.5 to 30 μm, the original cellulosic fiber It is possible to impart functions such as deep color, matte and combability without impairing the mechanical properties and excellent texture, and to obtain cellulosic fibers particularly suitable for artificial hair.

When the average number of the concave portions per unit area is 0.001 / μm ² or more, a matting effect is exhibited, and a cellulose fiber having a texture similar to human hair with a suppressed surface gloss can be obtained. In addition, the irregular color reflection of light on the fiber surface improves the deep color of the cellulosic fiber. Furthermore, since the contact area between the fibers is reduced, the combability is improved when artificial hair is used. The average number of the concave portions per unit area is more preferably 0.003 / μm ² or more, further preferably 0.005 / μm ² or more, and preferably 0.01 / μm ² or more. Is particularly preferred.

On the other hand, when the average number of the concave portions per unit area is 0.5 / μm ² or less, the mechanical properties of the cellulosic fiber are not impaired and the fiber is suitably used as a fiber structure such as artificial hair or woven or knitted fabric. And it has excellent durability during use. The average number of the recesses per unit area is more preferably 0.3 / μm ² or less, further preferably 0.2 / μm ² or less, and 0.1 / μm ² or less. Is particularly preferred.

  When the average diameter of the concave portions is 0.5 μm or more, a matting effect is exhibited, and cellulose fiber having a texture similar to human hair with suppressed surface gloss can be obtained. In addition, the irregular color reflection of light on the fiber surface improves the deep color of the cellulosic fiber. Furthermore, since the contact area between the fibers is reduced, the combability is improved when artificial hair is used. The average diameter of the concave portions is more preferably 0.7 μm or more, further preferably 1.0 μm or more, and particularly preferably 1.5 μm or more. On the other hand, if the average diameter of the concave portions is 30 μm or less, the mechanical properties of the cellulosic fiber can be suitably used as a fiber structure such as artificial hair or woven or knitted fabric without impairing the mechanical properties of the cellulosic fiber. Excellent in nature. The average diameter of the concave portion is more preferably 20 μm or less, further preferably 15 μm or less, and particularly preferably 10 μm or less.

  The method of forming the concave portion will be described in detail later, but it is preferable to subject the cellulose-based fiber containing inert particles such as silica particles to alkali treatment, and the inert treatment causes the inert particles to fall off from the fiber surface layer by the alkali treatment, and the fiber surface to be removed. This is preferable because a concave portion can be formed on the substrate.

  The cellulosic fiber is a fiber composed of a cellulose ester and / or cellulose, and in the present invention, it is preferably a fiber composed of a cellulose ester and a cellulose. Cellulose esters have a low refractive index and are excellent in coloring properties when formed into fibers. Further, when at least some of the acyl groups have 3 to 18 carbon atoms, the flexibility of the fibers is further increased, and artificial hair or woven fabric is used. Excellent texture when used as a fiber structure such as a knit. On the other hand, cellulose has excellent heat resistance and hygroscopicity as compared with cellulose esters.

  The cellulose-based fiber of the present invention has a core-sheath composite structure containing a cellulose ester having at least a part of an acyl group having 3 to 18 carbon atoms and a cellulose, as a configuration utilizing these features of the cellulose ester and the cellulose. It is preferable that the core has the cellulose ester as a main component, and the sheath has the cellulose as a main component. Here, the main component means 50% by mass or more of all components, preferably 60% by mass or more, more preferably 70% by mass, and further preferably 80% by mass or more. By adopting such a configuration, a cellulosic fiber having excellent aesthetics, heat resistance and hygroscopicity can be obtained. That is, in the case of employing such a configuration, it is possible to obtain a cellulosic fiber having excellent color developability by using a cellulose ester as the main component in the core portion and excellent hygroscopicity by using the cellulose as the main component in the sheath portion. In addition, since the sheath portion is mainly composed of cellulose having higher heat resistance than cellulose ester, it is possible to obtain a cellulosic fiber having excellent heat resistance to an iron or a dryer. Furthermore, since the cellulose ester in the core can be dyed with a disperse dye and the cellulose in the sheath with a reactive dye, only the core or the sheath can be selectively dyed, or the core and the sheath have different hues. It is preferable because different colors can be dyed with the above dye. In particular, when dyeing with different colors is preferable, since aesthetics that cannot be obtained by dyeing with one type of dye are exhibited. When performing different color dyeing, the hue of the obtained fiber can be controlled by the ratio of the core and the sheath.

  Specific examples of the cellulose ester in which at least a part of the acyl group has 3 to 18 carbon atoms include, but are not limited to, cellulose acetate propionate, cellulose propionate, cellulose acetate butyrate, and cellulose butyrate. . As a cellulose ester, cellulose acetate propionate in which cellulose has an acetyl group having 2 acyl carbon atoms and a propionyl group having 3 acyl carbon atoms, and / or cellulose has 2 acyl carbon atoms It is preferable to use cellulose acetate butyrate in which an acetyl group and a butyryl group having an acyl group having 4 carbon atoms are bonded, since cellulose fibers having more appropriate flexibility and hygroscopicity can be obtained.

When cellulose acetate propionate and / or cellulose acetate butyrate is used as the cellulose ester, the total substitution degree (acetyl substitution degree + acyl substitution degree) of the cellulose ester preferably satisfies the following formula (I). The degree of substitution is the number of substituents chemically bonded to three hydroxyl groups present in the glucose unit of cellulose. In addition, the acyl substitution degree is the sum of the substitution degrees of acyl groups other than the acetyl group having 2 carbon atoms in the acyl group. It is preferable that the total substitution degree (acetyl substitution degree + acyl substitution degree) of the cellulose ester is in the range of 2.5 or more and 3.0 or less, since a cellulose-based fiber having appropriate flexibility and hygroscopicity can be obtained. The total degree of substitution of the cellulose ester is more preferably from 2.6 to 2.9, even more preferably from 2.65 to 2.85.
(I) 2.5 ≦ acetyl substitution degree + acyl substitution degree ≦ 3.0
The degree of acetyl substitution and the degree of acyl substitution are determined by the following formulas (II) and (III) in order to obtain a cellulosic fiber having a high thermal softening temperature and having appropriate flexibility and hygroscopicity and a fiber structure such as artificial hair. Is preferable.
(II) 1.5 ≦ acetyl substitution degree ≦ 2.5
(III) 0.5 ≦ acyl substitution degree ≦ 1.5
It is preferable that the weight average molecular weight (Mw) of at least a part of the cellulose ester constituting the cellulosic fiber of the present invention, which has 3 to 18 acyl group carbon atoms, is 50,000 to 250,000. Although the details of the method for measuring the weight average molecular weight (Mw) will be described later, it is a value calculated by GPC measurement. When the weight average molecular weight (Mw) is 50,000 or more, the fiber strength of the cellulosic fiber is high, and a fiber structure such as artificial hair having sufficient durability can be obtained, which is preferable. The weight average molecular weight (Mw) is more preferably 60,000 or more, and further preferably 80,000 or more. On the other hand, when the weight average molecular weight (Mw) is 250,000 or less, the flexibility of the cellulosic fiber is high, and a fiber structure such as artificial hair having an excellent touch can be obtained. The weight average molecular weight (Mw) is more preferably 220,000 or less, further preferably 200,000 or less.

The cellulosic fiber of the present invention preferably contains inert particles such as inorganic particles and organic particles. Here, the term "inert" means that it does not have a property that causes a reaction such as a cross-linking reaction or a decomposition reaction to the cellulose and / or cellulose ester contained in the cellulose ester composition or the cellulosic fiber during production or storage. Say. By containing inert particles, by selecting appropriate conditions during the alkali treatment of the cellulosic fiber described below, it is possible to more easily form the concave portion on the fiber surface, and to obtain a deep coloration. Therefore, it is preferable. In addition, in the core containing a cellulose ester as a main component, it is preferable because inert particles present in the core irregularly reflect light and can give depth to color. Further, the dye penetrates into the inert particles existing in the core portion containing cellulose ester as a main component and the sheath portion containing cellulose as a main component.
Specific examples of the inert particles include oxides such as calcium carbonate, silicon oxide, titanium oxide and aluminum oxide, calcium phosphate, calcium monohydrogen phosphate, calcium dihydrogen phosphate, potassium phosphate, potassium monohydrogen phosphate, and phosphoric acid. Examples include, but are not limited to, phosphates such as potassium dihydrogen and antimony phosphate, sulfates such as barium sulfate and calcium sulfate, cross-linked polystyrene, and the like. Among them, silica particles containing silicon oxide as a main component are preferable because they have good handleability and are excellent in deep color and matting when concave portions are formed on the fiber surface. In addition, specific examples of the silica particles include, but are not limited to, dry silica, wet silica, silica sol, silica gel, and white carbon. These inert particles may be used alone or in combination.

  The content of the inert particles in the present invention is preferably 1 to 20 parts by mass with respect to 100 parts by mass in total of components other than the inert particles of the cellulose ester composition. When the content of the inert particles is 1 part by mass or more, when a concave portion is formed on the fiber surface by alkali treatment of the cellulosic fiber, the matte effect is more easily expressed and the surface gloss is suppressed. This is preferable because it is possible to efficiently obtain cellulosic fibers having a texture close to hair. The content of the inert particles is more preferably 2 parts by mass or more, further preferably 3 parts by mass or more, and particularly preferably 5 parts by mass or more. On the other hand, when the content of the inert particles is 20 parts by mass or less, when the concave portion is formed on the fiber surface by alkali treatment of the cellulosic fiber, the mechanical properties of the cellulosic fiber are not impaired, and the artificial hair It is preferable because it can be suitably used as a fibrous structure, etc., and has excellent durability when used. In addition, in the spinning, drawing, weaving, and knitting steps, the abrasion of the guides due to the inert particles is suppressed, and the process passability is improved. The content of inert particles is more preferably 17 parts by mass or less, further preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less.

  The cellulosic fiber of the present invention may have been subjected to various modifications by a secondary additive. Specific examples of the secondary additives include compatibilizers, ultraviolet absorbers, infrared absorbers, optical brighteners, mold release agents, lubricants, antibacterial agents, nucleating agents, heat stabilizers, antioxidants, and antistatic agents. Agents, anti-coloring agents, adjusters, matting agents, deodorants, anti-foaming agents, tinting agents, flame retardants, yarn friction reducing agents, preservatives, gelling agents, latex, fillers, inks, coloring agents, dyes , Pigments, fragrances and the like, but are not limited thereto. These secondary additives may be used alone or in combination of two or more.

  The cellulosic fiber of the present invention may be a multifilament consisting of two or more single yarns or a monofilament consisting of one single yarn. It has a close texture, and is excellent in deep color, matting, and combability, and is therefore preferable because it can be suitably used particularly for artificial hair. Further, it can be suitably used as a woven or knitted fabric for clothing, an auxiliary material for clothing such as a core of a collar or a sleeve, or a living material such as a curtain. The cross-sectional shape of the monofilament when the cellulosic fiber of the present invention is a monofilament and the cross-sectional shape of the single yarn constituting the multifilament when the cellulosic fiber is a multifilament are not particularly limited, and a perfect circular circular cross section Or a non-circular cross section. Specific examples of non-circular cross-sections include, but are not limited to, multilobal, polygonal, flat, elliptical, C-shaped, H-shaped, S-shaped, T-shaped, W-shaped, X-shaped, Y-shaped, etc. Not done.

  The fineness of the cellulosic fiber of the present invention is preferably 10 to 1500 dtex. A fineness of 10 dtex or more is preferable because it can be used as artificial hair having an appearance and feel close to human hair. The fineness is more preferably 20 dtex or more, further preferably 30 dtex or more, and particularly preferably 50 dtex or more. On the other hand, if the fineness is 1500 dtex or less, the flexibility is not impaired when a fiber structure such as a woven or knitted fabric is used. The fineness is more preferably 1000 dtex or less, further preferably 500 dtex or less, and particularly preferably 300 dtex or less.

  The average fiber diameter of the cellulosic fiber of the present invention is preferably 25 to 500 µm. Although the details of the method of measuring the average fiber diameter will be described later, when the fiber cross section is not a perfect circle, the average fiber diameter is calculated from the diameter of a circumscribed circle of the fiber cross section. An average fiber diameter of 25 μm or more is preferable because it can be used as artificial hair having an appearance and feel close to human hair. The average fiber diameter is more preferably at least 50 μm, even more preferably at least 70 μm. On the other hand, when the average fiber diameter is 500 μm or less, it is preferable that the flexibility is not impaired when a fiber structure such as a woven or knitted fabric is used. The average fiber diameter is more preferably 400 μm or less, further preferably 300 μm or less, and particularly preferably 150 μm or less.

  The strength of the cellulosic fiber of the present invention is not particularly limited and can be appropriately selected depending on the application and required characteristics, but is preferably 0.5 to 2.5 cN / dtex from the viewpoint of mechanical characteristics. . If the strength is 0.5 cN / dtex or more, it is preferable because yarn breakage is small in the weaving and knitting steps, the process passability is good, and the durability during use is excellent. The strength is more preferably at least 1.0 cN / dtex, even more preferably at least 1.5 cN / dtex. On the other hand, if the strength is 2.5 cN / dtex or less, the flexibility is not impaired in the case of a fiber structure such as artificial hair or woven or knitted fabric, which is preferable.

  The elongation of the cellulosic fiber of the present invention is not particularly limited and may be appropriately selected depending on the application and required characteristics, but is preferably from 10 to 50% from the viewpoint of processability. When the elongation is 10% or more, the abrasion resistance of the fiber is good, and when a fiber structure such as artificial hair or woven or knitted fabric is used, generation of fluff during use is small and durability is good. preferable. The elongation is more preferably at least 15%, even more preferably at least 20%. On the other hand, when the elongation is 50% or less, the dimensional stability of a fiber structure such as artificial hair or woven or knitted fabric is improved, which is preferable. The elongation is more preferably 45% or less, further preferably 40% or less.

  The initial tensile resistance of the cellulosic fiber of the present invention is not particularly limited and can be appropriately selected depending on the application and required characteristics. The initial tensile resistance measured according to JIS L1013: 1999, 8.10 is used. Is preferably 20 to 50 cN / dtex. An initial tensile resistance of 20 cN / dtex or more is preferable because it can be used as artificial hair having tension and firmness that is very close to the feel of human hair. The initial tensile resistance is more preferably 23 cN / dtex or more, and even more preferably 25 cN / dtex or more. On the other hand, if the initial tensile resistance is 50 cN / dtex or less, it is preferable because the flexibility is not impaired when a fiber structure such as artificial hair or woven or knitted fabric is used. The initial tensile resistance is more preferably 47 cN / dtex or less, and further preferably 45 cN / dtex or less.

  The difference in moisture absorption (ΔMR) of the cellulosic fiber of the present invention is preferably 1 to 10%. The details of the method of measuring the MR will be described later, but the moisture absorption rate at a temperature of 30 ° C. and a humidity of 90% RH assuming the temperature and humidity inside the clothes after a light run, and a temperature of 20 ° C. and a humidity of 65% RH as the outside air humidity Is ΔMR. That is, ΔMR is an index of hygroscopicity, and the higher the value of ΔMR, the better the wearing comfort. When the ΔMR is 1% or more, the feeling of stuffiness at the time of wearing is small and the wearing comfort is expressed, which is preferable. ΔMR is more preferably 1.5% or more, and further preferably 2% or more. On the other hand, when the ΔMR is 10% or less, the handleability is good when the fiber structure is made of artificial hair or woven or knitted fabric, and the durability during use is excellent. ΔMR is more preferably 9% or less, further preferably 8% or less.

  The cellulosic fiber of the present invention preferably has a frictional voltage of 1500 V or less at a temperature of 20 ° C. and a humidity of 40% RH. Although the details of the method of measuring the frictional band voltage will be described later, the frictional band voltage is an index of antistatic property, and the lower the value of the frictional band voltage, the more the generation of static electricity is suppressed. The smaller the frictional band voltage is, the better from the viewpoint of wearing comfort. When the friction band voltage is 1500 V or less, static electricity is less likely to be generated when the hair is worn, and the combability is improved when artificial hair is used. The friction band voltage is more preferably 1200 V or less, further preferably 1000 V or less, and particularly preferably 700 V or less.

  The cellulosic fiber of the present invention can be processed by drawing or the like in the same manner as general fibers. In addition, weaving and knitting can be handled in the same manner as ordinary fibers.

  Next, a method for producing the cellulosic fiber of the present invention will be described.

  The cellulose ester composition used as a raw material to obtain the cellulosic fiber of the present invention contains a cellulose ester having at least a part of an acyl group having 3 to 18 carbon atoms, a plasticizer, a phosphorus-based antioxidant, and inert particles. Is preferred.

  The cellulose ester composition used as a raw material for obtaining the cellulosic fiber of the present invention may contain a plasticizer, and a polyhydric alcohol compound is preferable as the plasticizer. Specific examples of the plasticizer include polyalkylene glycol, which has good compatibility with cellulose ester and has a remarkable melt-spinning thermoplasticity effect, glycerin-based compounds, and caprolactone-based compounds. Is preferred. Specific examples of the polyalkylene glycol include, but are not limited to, polyethylene glycol, polypropylene glycol, and polybutylene glycol having a weight average molecular weight of 200 to 4000. These plasticizers may be used alone or in combination.

  The content of the plasticizer in the cellulose ester composition used as a raw material for obtaining the cellulosic fiber of the present invention is preferably 5 to 25% by mass based on the entire cellulose ester composition. When the content of the plasticizer is 5% by mass or more, the cellulose ester composition is preferably melt-spinnable because a thermoplastic effect can be obtained. The content of the plasticizer is more preferably 8% by mass or more, and further preferably 10% by mass or more. On the other hand, when the content of the plasticizer is 25% by mass or less, the fiber strength of the cellulosic fiber is high, and a fiber structure such as artificial hair having sufficient durability can be obtained. The content of the plasticizer is more preferably 22% by mass or less, and further preferably 20% by mass or less.

  The cellulosic fiber of the present invention preferably contains a phosphorus-based antioxidant. When a phosphorus-based antioxidant is contained, the thermal decomposition-preventing effect is good, and a decrease in the mechanical properties and coloring of the cellulosic fiber are suppressed. Specific examples of the phosphorus antioxidant include tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite and tetrakis (2,6-di-t -Butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite, tetrakis (2,6-di-t-butylphenyl-4-methyl) [1,1-biphenyl] -4,4 '-Diylbisphosphonite, bis (2.6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2-t-butyl-4-cumylphenyl) pentaerythritol diphosphite, bis ( 4-t-butyl-2-cumylphenyl) pentaerythritol diphosphite, bis (2.6-di-t-butyl-4-ethylphenyl) pentaerythritol diphosphite, bis (2.4-diphenyl Such as t- butyl-6-methylphenyl) pentaerythritol diphosphite include, but are not limited to. Among them, pentaerythritol compounds are preferable because of their high antioxidant effect.

  The content of the phosphorus-based antioxidant in the cellulose ester composition used as a raw material for obtaining the cellulosic fiber of the present invention may be 0.005 to 0.5% by mass based on the entire cellulose ester composition. preferable. It is preferable that the content of the phosphorus-based antioxidant is 0.005% by mass or more, because it is possible to suppress deterioration and coloring of the mechanical properties of the cellulosic fiber due to thermal decomposition. The content of the phosphorus-based antioxidant is more preferably 0.01% by mass or more, further preferably 0.05% by mass or more. On the other hand, when the content of the phosphorus-based antioxidant is 0.5% by mass or less, the effect on the fiber properties of the cellulosic fiber is small, and a fiber structure such as artificial hair having an excellent texture is obtained, which is preferable. The content of the phosphorus-based antioxidant is more preferably 0.3% by mass or less, and further preferably 0.2% by mass or less.

  In the method for producing the cellulose ester composition of the present invention, the mixing of the cellulose ester, the plasticizer, the phosphorus-based antioxidant, and the inert particles can employ a known method, for example, an extruder, a kneader, a roll mill, Examples include, but are not limited to, Banbury mixers. In order to facilitate the mixing, the cellulose ester particles may be finely pulverized to 50 mesh or more by a pulverizer in advance, and a plasticizer, a phosphorus-based antioxidant, an inert Particles may be added.

  Cellulose-based fibers can be obtained by melt-spinning a cellulose ester composition. Unlike wet spinning and dry spinning, melt spinning does not use a solvent, so there is no need to remove the solvent from the fiber surface or inside the fiber, which is preferable because a cellulose-based fiber having a large single-filament fineness can be obtained. Further, the melt spinning is preferable because a sufficiently developed fiber structure can be formed from the molten state of the cellulose ester composition to the cooling and solidification.

  In the present invention, the previously dried chip-shaped cellulose ester composition is supplied to a melt spinning machine such as an extruder type or a pressure melter type, melted, and measured by a measuring pump. Thereafter, the molten polymer is introduced into a heated spinning pack in the spinning block, and the molten polymer is filtered in the spinning pack, and then discharged from a spinneret to form a fiber yarn. The fiber yarn discharged from the spinneret is cooled and solidified by a cooling device, taken up by a first godet roller, wound up by a winder via a second godet roller, and formed into a wound yarn. In addition, a heating cylinder or a heat insulation cylinder having a length of 2 to 20 cm may be provided below the spinneret as necessary in order to improve the yarn operability, productivity, and mechanical properties of the fiber. Further, the lubricating device may be used to lubricate the fiber yarns, or the entanglement device may be used to impart entanglement to the fiber yarns.

  In the present invention, it is preferable that the cellulose ester composition is dried before the melt spinning, and the water content is set to 0.3% by mass or less. It is preferable that the water content is 0.3% by mass or less, since the spinning can be stably performed without foaming due to moisture during melt spinning. Further, it is preferable because a decrease in mechanical properties due to hydrolysis during melt spinning can be suppressed. The water content is more preferably 0.2% by mass or less, further preferably 0.1% by mass or less, and particularly preferably 0.08% by mass or less.

  The spinning temperature in melt spinning is preferably from 220 to 280 ° C. When the spinning temperature is 220 ° C. or higher, the cellulosic fiber having a uniform cross-sectional shape without a short pitch, because the elongational viscosity of the fiber yarn discharged from the spinneret is sufficiently reduced, the discharge is stable. Is preferred because In addition, the spinning tension is not excessively high, and the yarn breakage can be suppressed, which is preferable. The spinning temperature is more preferably 230 ° C or higher, and further preferably 240 ° C or higher. On the other hand, when the spinning temperature is 280 ° C. or lower, the thermal decomposition of the cellulose ester composition can be suppressed, and a decrease in the mechanical properties due to a decrease in the molecular weight and a deterioration in the quality due to coloring do not occur. The spinning temperature is more preferably 275 ° C or lower, and even more preferably 270 ° C or lower.

  The fiber yarn discharged from the spinneret may be guided to a cooling bath and rapidly cooled. The temperature of the cooling bath is preferably from 10 to 90C. If the temperature of the cooling bath is 10 ° C. or higher, it is preferable because a fiber-based fiber having a uniform fiber cross-sectional shape and a uniform fiber diameter can be obtained without meandering the fiber yarn in the cooling bath. The temperature of the cooling bath is more preferably 15 ° C. or higher, further preferably 20 ° C. or higher. On the other hand, when the temperature of the cooling bath is 90 ° C. or lower, it is preferable because it is possible to obtain a cellulosic fiber having a uniform fiber cross-sectional shape and fiber diameter without impairing the circularity of the fiber yarn. The temperature of the cooling bath is more preferably 80 ° C or lower, further preferably 70 ° C or lower. In addition, the cooling time can be appropriately adjusted according to the discharge amount, the number of die holes, and the like.

  As a coolant for the cooling bath, a substance that can be easily removed from the surface of the fiber yarn and does not give a physical change or a chemical change to the fiber yarn, and is a liquid within the above-described cooling bath temperature range. Can be used without any particular limitation. Specific examples of the coolant of the cooling bath include, but are not limited to, water, paraffin, ethylene glycol, glycerin, amyl alcohol, xylene, and the like.

  The method of taking out the spun fiber includes a method of taking up using a rotating roller, but is not limited to this. The spinning speed in the case of using a rotating roller for drawing is preferably 1500 m / min or less. It is preferable that the spinning speed is 1500 m / min or less, since the fibers can be sufficiently cooled. The spinning speed is more preferably 1000 m / min or less, and further preferably 750 m / min or less.

  The drawn fiber may be drawn to obtain a cellulosic fiber having the desired fiber properties. When the drawing is performed, either a two-step method of drawing the fiber once drawn or a direct spin drawing method of continuously drawing without drawing may be used.

  When stretching is performed, any of a single-stage stretching method and a multi-stage stretching method of two or more stages may be used. The heating method in the drawing is not particularly limited as long as it can directly or indirectly heat the running yarn. Specific examples of the heating method include, but are not limited to, a heating roller, a hot pin, a hot plate, a hot water, a liquid bath such as hot water, a hot air, a gas bath such as steam, and a laser. These heating methods may be used alone or in combination. As the heating method, from the viewpoint of controlling the heating temperature, uniform heating of the running yarn, and not complicating the device, contact with a heating roller, contact with a heating pin, contact with a heating plate, immersion in a liquid bath Can be suitably adopted.

  The stretching ratio when performing stretching can be appropriately selected according to the strength and elongation of the drawn fiber, but is preferably 1.02 to 4.0 times. A draw ratio of 1.02 times or more is preferable because mechanical properties such as fiber strength and elongation can be improved by drawing. The stretching ratio is more preferably 1.05 times or more, and further preferably 1.08 times or more. On the other hand, when the stretching ratio is 4.0 times or less, breakage of yarn at the time of stretching is suppressed, and stable stretching can be performed. The stretching ratio is more preferably 3.7 times or less, and even more preferably 3.5 times or less.

  The stretching temperature at the time of stretching can be appropriately selected according to the strength and elongation of the drawn fiber, but is preferably 30 to 200 ° C. When the stretching temperature is 30 ° C. or higher, the yarn supplied for stretching is sufficiently preheated, the thermal deformation during stretching becomes uniform, and the occurrence of fineness unevenness can be suppressed. The stretching temperature is more preferably 35 ° C. or higher, further preferably 40 ° C. or higher. On the other hand, when the stretching temperature is 200 ° C. or lower, it is preferable because the thermal decomposition of the cellulosic fiber can be suppressed. In addition, since the slipperiness of the fiber with respect to the drawing roller is improved, breakage of the yarn is suppressed, and stable drawing can be performed. The stretching temperature is more preferably 185 ° C or lower, and even more preferably 170 ° C or lower. Moreover, you may perform the heat setting of 120 degreeC-180 degreeC as needed.

  The stretching speed for stretching can be appropriately selected depending on whether the stretching method is a one-step method or a two-step method. In the case of the one-step method, the speed of the high-speed roller at the spinning speed corresponds to the drawing speed. The stretching speed when performing stretching by the two-step method is preferably 30 to 1000 m / min. When the stretching speed is 30 m / min or more, the running yarn is stable and yarn breakage is suppressed, which is preferable. When the stretching is performed by the two-step method, the stretching speed is more preferably 50 m / min or more, and further preferably 100 m / min or more. On the other hand, when the stretching speed is 1000 m / min or less, yarn breakage during stretching is suppressed, and stable stretching can be performed, which is preferable. When the stretching is performed by the two-step method, the stretching speed is more preferably 800 m / min or less, and further preferably 500 m / min or less.

  In order to obtain a cellulosic fiber of the present invention, or a fibrous structure such as artificial hair or woven or knitted fabric made of the cellulosic fiber, it is preferable to perform an alkali treatment in any of the steps from the fiberization step to the final product. . Since the hydrolysis of the cellulose ester proceeds from the fiber surface layer by the alkali treatment and becomes cellulose, a cellulose-based fiber having a core-sheath composite structure composed of a core portion made of cellulose ester and a sheath portion made of cellulose can be obtained. preferable. In addition, the alkali treatment is preferable because the inert particles fall off from the fiber surface layer and a concave portion can be formed on the fiber surface.

  The present inventors have conducted intensive studies on the alkali treatment method in the present invention. As a result, when the hydrolysis of the cellulose ester progressed completely and became a fiber consisting only of cellulose, the fiber surface was not a concave portion but a convex portion. Is formed. That is, in order to form a concave portion on the surface of the fiber, it has been conceived that it is important to use a cellulose-based fiber having a core-sheath composite structure including a core made of cellulose ester and a sheath made of cellulose.

  In general, a polyester fiber produced by adding inert particles has a convex portion formed on the fiber surface due to the presence of the particles. When the fiber is subjected to alkali treatment, hydrolysis of the polyester proceeds from the fiber surface layer, and the low-molecular-weight polyester is eluted into the alkaline aqueous solution, and inactive particles fall off to form recesses on the fiber surface. In the cellulosic fiber of the present invention as well, before the alkali treatment, convex portions are formed on the fiber surface as shown in FIG. 3 due to the presence of the inert particles. When the fiber is subjected to alkali treatment, hydrolysis of the cellulose ester proceeds from the fiber surface layer, inactive particles fall off, a concave portion is formed on the fiber surface as shown in FIG. 1, and hydrolysis of the cellulose ester completely proceeds. Then, a convex portion is formed again on the fiber surface as shown in FIG. Unlike polyester, in the case of cellulose ester, cellulose produced by hydrolysis does not elute into an alkaline aqueous solution, so that the formation behavior of concave portions and convex portions on the fiber surface due to alkali treatment is different.

  The alkali treatment method is not particularly limited, but a method using an aqueous solution containing an alkali compound can be suitably employed. Specific examples of the alkali compound include, but are not limited to, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and weak acid salts of alkali metals such as sodium carbonate and potassium carbonate. These alkali compounds may be used alone or in combination. Among them, sodium hydroxide and sodium carbonate can be suitably used.

  The concentration of the alkali compound in the aqueous alkali solution used for the alkali treatment can be appropriately selected according to the strength of the alkali compound, the treatment temperature, and the treatment time. For example, when a strong alkali alkali metal hydroxide is used, the concentration of the alkali compound is preferably 0.5 to 10% by mass. When the concentration of the alkali compound is 0.5% by mass or more, the alkali treatment can be performed efficiently and the productivity is improved, which is preferable. The concentration of the alkali compound is more preferably 0.7% by mass or more, further preferably 1.0% by mass or more, and particularly preferably 1.5% by mass or more. On the other hand, when the concentration of the alkali compound is 10% by mass or less, embrittlement of the fiber due to the alkali treatment can be suppressed, which is preferable. The concentration of the alkali compound is more preferably 7% by mass or less, further preferably 5% by mass or less, and particularly preferably 3% by mass or less.

  When performing alkali treatment, a known alkali weight loss promoter such as a quaternary ammonium salt may be used, if necessary. It is preferable to use an alkali weight loss promoter because alkali hydrolysis proceeds in a short time.

  Alkali treatment, depending on the shape of the object to be alkali treated, cheese dyeing machine, liquid jet dyeing machine, wins, zicker, beam dyeing machine used for normal dyeing processing, and normal pressure steam after applying the processing liquid to the pad , Pressurized steam, a method of dry heat treatment, and the like can be used as appropriate, but are not limited thereto.

  In the alkali treatment of the present invention, by appropriately adjusting the type, concentration, treatment temperature, and treatment time of the alkali compound, a cellulose having a core-sheath composite structure including the above-described cellulose ester core and a cellulose sheath. A system fiber can be obtained, and the ratio of the core and the sheath can be controlled. When a strong alkali is used as the alkali compound, when the concentration of the alkali compound is high, when the treatment temperature is high, or when the treatment time is long, the proportion of the cellulose ester in the core becomes small, and finally, the cellulose ester Completely progresses to a fiber consisting only of cellulose.

  Since the cellulosic fiber of the present invention has a core-sheath composite structure composed of a core made of cellulose ester and a sheath made of cellulose, the cellulose ester in the core is a disperse dye, and the cellulose in the sheath is a reactive dye. Can be stained. When performing dyeing, dyeing may be performed in two steps using an aqueous solution containing a disperse dye and an aqueous solution containing a reactive dye, or may be performed in one step using an aqueous solution containing both a disperse dye and a reactive dye. However, dyeing in one stage can be suitably employed because the number of steps is small and the productivity is good.

  As the disperse dye, an acetate disperse dye or a polyester disperse dye can be suitably used, and the dyeing temperature is not particularly limited, but is preferably from 80 to 110 ° C. As the reactive dye, a reactive dye for cellulose can be suitably used, and the dyeing temperature is not particularly limited, but is preferably from 80 to 110 ° C. A dyeing temperature of 80 ° C. or higher is preferable because the dye can be efficiently exhausted into the cellulosic fiber. On the other hand, if the dyeing temperature is 110 ° C. or lower, it is preferable because a decrease in mechanical properties due to embrittlement of the cellulosic fiber can be suppressed.

  The dyeing method is not particularly limited, and a known dyeing machine such as a cheese dyeing machine, a liquid jet dyeing machine, and a drum dyeing machine can be suitably used. To the aqueous solution used for dyeing, in addition to the above-mentioned disperse dyes and reactive dyes, known pH adjusters, pH slide agents, sodium sulfate, and various auxiliaries may be added in order to obtain vivid color development. After dyeing, excess dye may be washed by a known method. Examples include, but are not limited to, reduction cleaning with a reducing agent such as hydrosulfite, and cleaning with a surfactant or the like.

  The form of the fibrous structure comprising the cellulosic fiber of the present invention is not particularly limited, and can be formed into a woven fabric, a knitted fabric, a pile fabric, a nonwoven fabric, or the like according to a known method. Further, the fibrous structure comprising the cellulosic fiber of the present invention may have any woven or knitted structure, such as plain weave, twill weave, satin weave or their modified weave, warp knit, weft knit, circular knit, lace. A knitting or a change thereof can be suitably adopted.

  The cellulosic fiber of the present invention may be combined by interweaving or knitting of the cellulosic fiber and other fibers when forming a fiber structure, or as a mixed fiber of the cellulosic fiber and other fibers. The fiber structure may be manufactured later.

  Since the cellulosic fiber of the present invention has a texture close to that of human hair, and is excellent in deep color, matte, and combability, it can be particularly preferably used as artificial hair. Specifically, it can be used as a head decoration product such as a hair wig, two-piece, weaving, hair extension, blade, hair accessory, and doll hair, but is not limited thereto. The hair wig is a decorative item attached to the head with a surface, and is classified into a partial wig, a half wig, a seven-minute wig, and a full wig according to its attachment surface. Further, "Tupe" is a general term for a wig attached to a part or the whole head, and is a head decoration product made by implanting artificial hair on a pseudo scalp.

  Using the cellulosic fiber of the present invention, these head decoration products can be processed according to a known method. For example, when producing a hair wig, the bundle of fibers is sewn with a sewing machine for a wig to produce a hair, which is wound around a pipe and steam-set to give a curl, and the hair with the curl is put on a hair cap. It can be manufactured by sewing on and styling.

  When producing these headdress products, the cellulosic fiber of the present invention may be used in combination with other artificial hair materials such as modacrylic fiber, polyvinyl chloride fiber, nylon fiber, and human hair or Animal hair or the like may be used in combination.

  Since the cellulosic fiber of the present invention has a texture close to that of human hair, and is excellent in deep color, matte and combability, it can be suitably used particularly for artificial hair. In addition, it can be suitably used as an auxiliary material for clothing such as a woven or knitted fabric for clothing, a core of a collar or a sleeve, and a living material such as a curtain.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, each characteristic value in the examples is obtained by the following method. In addition, in the evaluation method of each characteristic value, evaluation was performed at n = 1 unless otherwise specified.

A. Average degree of substitution of cellulose ester A cellulose ester (hereinafter, referred to as a sample in the description of this evaluation) was dried at 80 ° C. for 8 hours, weighed 0.9 g, and dissolved by adding 35 ml of acetone and 15 ml of dimethyl sulfoxide. 50 ml of acetone were added. While stirring, 30 ml of a 0.5 N aqueous sodium hydroxide solution was added, and the mixture was saponified for 2 hours. After adding 50 ml of hot water and washing the side surface of the flask, titration was performed with 0.5N-sulfuric acid using phenolphthalein as an indicator.

  Titration was performed in the same manner as above except that the cellulose ester sample was not added (to be distinguished from the above titration, a blank test was performed).

  The supernatant of the solution after the titration (of the sample) was diluted 100-fold, and the composition of the organic acid (molar ratio of acetic acid to another organic acid) was analyzed by ion chromatography.

  The average degree of substitution was calculated by the following equation from the results of titration of the saponified sample and blank test of the sample and the results of analysis of the composition of the organic acid by ion chromatography.

TA = (BA) × F / (1000 × W)
DSace = (162.14 × TA) / [{1- (Mwace− (16.0 + 1.01)) × TA} + {1- (Mwacy− (16.00 + 1.01)) × TA} × (Acy / Ace)]
DSacy = DSace × (Acy / Ace)
TA: Total organic acid amount (ml)
A: Titration of 0.5N-sulfuric acid to the sample (ml)
B: Titration of 0.5N-sulfuric acid in blank test (ml)
F: Sulfuric acid titer W: Sample mass (g)
DSace: average degree of substitution of acetyl group DSacy: average degree of substitution of acyl group Mwace: molecular weight of acetic acid Mwacy: molecular weight of another organic acid Acy / Ace: molar ratio of acetic acid (Ace) to another organic acid (Acy) 162 .14: molecular weight of repeating unit of cellulose 16.00: atomic weight of oxygen 1.01: atomic weight of hydrogen Weight average molecular weight (Mw) of cellulose ester
The cellulose ester was completely dissolved in tetrahydrofuran so as to have a concentration of 0.15% by mass to prepare a sample solution for GPC measurement. Using this sample solution, GPC measurement was performed with Waters 2690 under the following conditions, and the weight average molecular weight (Mw) was calculated in terms of polystyrene. The GPC measurement was performed three times for one sample solution, and the average value was defined as a weight average molecular weight (Mw).

Column: Two TSK gel GMHHR-H manufactured by Tosoh Detector: Waters2410 Differential refractometer RI
Moving layer solvent: tetrahydrofuran Flow rate: 1.0 ml / min Injection volume: 200 μl
C. Core ratio Dyeing was performed at 110 ° C. for 60 minutes at a bath ratio of 1: 100 in a dyeing solution adjusted to pH 5.0 using a disperse dye of 3% by mass based on the obtained monofilament bundle. . As a disperse dye, Nippon Kayaku Kayalon Polyester Black EX-SF200 was used. When the main raw material was polyethylene terephthalate, the dyeing temperature was 130 ° C. After dyeing, the cross section of the monofilament fiber contained in the monofilament bundle was observed with an optical microscope, and a micrograph was taken. For the photograph taken, the area of the cross section of the fiber of the monofilament and the area of the portion dyed with the disperse dye were measured, and the ratio (%) of the core was calculated using the following equation. In addition, the measurement was performed about 20 monofilaments, and the average value was made into the ratio (%) of a core part.
Core ratio (%) = Area of part dyed with disperse dye / Area of fiber cross section × 100
D. Fineness A monofilament was collected from the obtained bundle of monofilaments, cut into a length of 20 cm, the mass was measured, and the fineness (dtex) was calculated using the following equation. In addition, the measurement was performed 20 times per one level, and the average value was defined as fineness.
Fineness (dtex) = mass (g) of monofilament 20 cm x 50,000
E. FIG. Average fiber diameter Twenty monofilaments were collected from the obtained bundle of monofilaments, converged and fixed on a sample table, and a platinum-palladium alloy was deposited thereon. The cross section of the monofilament was observed using and the micrograph was taken. With respect to the photographed photographs, the diameter of the cross section of 20 monofilaments was measured, and the average value was defined as the average fiber diameter (μm). When the cross section of the monofilament was not a perfect circle, the diameter of the circumcircle of the cross section of the monofilament was measured, and the average fiber diameter was calculated.

F. Strength and Elongation A monofilament constituting the obtained bundle of monofilaments was used as a sample, and the strength and elongation were calculated according to JIS L1013: 1999 (Test method for chemical fiber filament yarn) 8.5. In an environment of a temperature of 20 ° C. and a humidity of 65% RH, a tensile test was performed using an Autograph AG-50 NISMS type manufactured by Shimadzu Corporation under the conditions of an initial sample length of 20 cm and a tensile speed of 20 cm / min. The strength (cN / dtex) is calculated by dividing the stress (cN) at the point showing the maximum load by the fineness (dtex), and using the elongation (L1) of the point showing the maximum load and the initial sample length (L0), The elongation (%) was calculated by the equation. The measurement was performed 10 times for each sample, and the average value was defined as the strength and elongation.
Elongation (%) = {(L1-L0) / L0} × 100
G. FIG. Initial tensile resistance The initial tensile resistance was calculated according to JIS L1013: 1999 (Test Method for Chemical Fiber Filament Yarn) 8.10 using a monofilament constituting the obtained bundle of monofilaments as a sample. A load-elongation curve is drawn by performing the measurement in the same manner as in the above F, and the maximum point of the load change with respect to the elongation change is determined near the origin of the curve, which is described in JIS L1013: 1999 (Chemical Fiber Filament Yarn Test Method) 8.10. Was used to calculate the initial tensile resistance (cN / dtex). The measurement was performed 10 times for each sample, and the average value was defined as the initial tensile resistance.

H. Average number of recesses per unit area, average diameter of recesses After depositing a monofilament constituting a bundle of obtained monofilaments with a platinum-palladium alloy, using a scanning electron microscope (SEM) S-4000 manufactured by Hitachi, The fiber surface was observed and a micrograph was taken.

Observation for obtaining the average number of recesses per unit area is performed at each magnification of 300 times, 500 times, 1000 times, 3000 times, 5000 times, and 10000 times on the fiber surface. The lowest magnification at which the monofilament occupies the entire observation field was selected. The photographed photo is equally divided into a total of 25 regions of 5 places and 5 places, and the number of recesses existing in the area is divided by the area of the area, and the recesses existing per 1 μm ² (Number / μm ² ) was calculated. The measurement was performed on ten regions randomly extracted from the same photograph, and the average value was defined as the average number of concave portions per unit area. When the average number of the concave portions per unit area was less than 0.001 / μm ² , the value was determined as <0.001 / μm ² .

Observation for obtaining the average diameter of the concave portions was performed at 300 ×, 500 ×, 1000 ×, 3000 ×, 5000 ×, and 10000 × magnifications on the fiber surface. The lowest magnification that can be observed was selected. With respect to the photographed photographs, the diameters of 100 concave portions randomly extracted from the same photograph were measured, and the average value was defined as the average diameter of concave portions (μm). Since the recess present in the fiber cross section is not always a perfect circle, the area was measured when the recess was not a perfect circle, and the diameter converted to a perfect circle was adopted as the diameter of the recess. Further, when the number of recesses present on the fiber surface was less than 100, the fiber surface was observed using a plurality of monofilaments constituting a bundle of monofilaments as a sample. When taking a micrograph, the highest magnification at which the entire image of the monofilament could be observed was selected. With respect to the photographed photograph, the diameter of the concave portion present on the fiber surface of each monofilament was measured, and the average value of the diameters of the total 100 concave portions was defined as the average diameter of the concave portion. When the average number of the concave portions per unit area was less than 0.001 / μm ² , the average diameter of the concave portions was not measured.

I. Moisture absorption difference (△ MR)
About 2 g of the monofilament constituting the bundle of the obtained monofilaments was used as a sample, and the moisture absorption (%) was calculated according to the moisture content of JIS L1096: 2010 (test method for fabric and knitted fabric) 8.10. The monofilament was dried under vacuum at 110 ° C. for 24 hours, and the mass (W0) of the monofilament when absolutely dried was measured. Next, the monofilament was allowed to stand in an ESPEC constant temperature and humidity machine LHU-123 conditioned at a temperature of 20 ° C. and a humidity of 65% RH for 24 hours, and the mass (W1) of the monofilament was measured. The monofilament was allowed to stand in a thermo-hygrostat adjusted to 90% RH for 24 hours, and the mass (W2) of the monofilament was measured. The moisture absorption rate MR1 (%) of the monofilaments when left undisturbed at a temperature of 20 ° C. and a humidity of 65% RH for 24 hours is calculated from the monofilament masses W0 and W1. The moisture absorption rate MR2 (%) when allowed to stand in an atmosphere of a temperature of 30 ° C. and a humidity of 90% RH for 24 hours was calculated, and the difference in moisture absorption rate (ΔMR) was calculated by the following equation. The measurement was performed five times for each sample, and the average value was defined as a difference in moisture absorption (ΔMR).

Moisture absorption difference (ΔMR) (%) = MR2-MR1
J. Friction band voltage Using the obtained monofilament as a sample, about 2 g of tubular knitting was produced using a circular knitting machine NCR-BL (3 inch and a half kettle, 27 gauge) manufactured by Eiko Sangyo. The tube knit was scoured with hot water at 70 ° C. for 20 minutes, washed with running water at 25 ° C. for 30 minutes, and dried in a hot air dryer at 60 ° C. for 60 minutes. Subsequently, after alkali treatment under the conditions described in each example, the substrate was washed with running water at 25 ° C. for 30 minutes, and dried in a hot air dryer at 60 ° C. for 60 minutes. Using the knitted tube after the alkali treatment as a sample, the friction band voltage (V) was measured at 20 ° C. and a humidity of 40% RH in accordance with JIS L1094: 1997 (Testing method for charging of woven fabric and knitted fabric) 5.2. Calculated. The measurement was performed five times for one sample, and the average value was defined as a frictional charged voltage.

K. L ^* value The obtained bundle of monofilaments was used as a sample, and two kinds of dyes of 3% by mass of a disperse dye and 3% by mass of a reactive dye were added to the sample, and 70 g / L of sodium sulfate was added as an auxiliary agent. The solution was dyed at 110 ° C. for 60 minutes in a dyeing solution adjusted to pH 7.0 at a bath ratio of 1: 100. In addition, Nippon Kayaku Polyalon Black EX-SF200 was used as a disperse dye, and Nippon Kayaku React Red CN-3B was used as a reactive dye. When the main raw material was polyethylene terephthalate, the dyeing temperature was 130 ° C. The L ^* value of the stained sample was measured using a Minolta spectrophotometer CM-3700d under a D65 light source, a viewing angle of 10 °, and optical conditions SCE. The measurement was performed three times for each sample, and the average value was defined as L ^* value.

L. Flexibility The obtained bundle of monofilaments was used as a sample, the flexibility was compared with human hair, and 10 examiners who had 5 years or more of experience in determining the quality determined that “the flexibility equivalent to human hair was There are ◎ for `` there is flexibility close to human hair '', ○ for `` slightly harder than human hair '', × for `` very hard compared to human hair '', and "Yes" or "Yes" was judged as acceptable.

M. Moisture absorption / release properties The difference in moisture absorption rate (ΔMR) evaluated in the above I is “2% or more and 8% or less”, ◎, “1% or more and less than 2%, or 8% or more and less than 10%” is ○, “0.5% Not less than 1% or less than 10% and less than 12% ”is marked with Δ, and“ less than 0.5% or less than 12% ”is marked X, and“ 1% or more and less than 2% or 8% or more but less than 10% ”is passed. And

N. Aesthetics A bundle of monofilaments after dyeing with K was used as a sample, and the aesthetics were evaluated. By consultation of 10 inspectors with 5 years or more of experience in determining the quality, "very aesthetically pleasing" ◎, "Abundant in aesthetics" was rated as "A", "Lack in aesthetics" was rated as "A", "Less in aesthetics" was rated as "X", and "Good in aesthetics" was rated as "Good" or more. In addition, aesthetics is an index relating to the beauty of appearance that is developed by dyeing with a dye having a different hue, and after dyeing using a black dye as a disperse dye and a red dye as a reactive dye as described in K above, Aesthetics were evaluated.

O. Deep colorability A bundle of monofilaments dyed with the above K was used as a sample, and compared with human hair for the deep colority. There are ◎ for `` very close to human hair '', 「for` `Slightly deep in color, close to human hair '', △ for` `Slightly deep in color, slightly inferior to human hair '', △ "Not very deep and extremely inferior to human hair" was evaluated as "Poor", and "Slightly deep in color and close to human hair" was evaluated as "Good" or more.

P. Matting property The obtained bundle of monofilaments was used as a sample, and compared with human hair in a visual evaluation when the incident angle of sunlight was 10 to 55 °, near a window in a room exposed to direct sunlight. By the consultation of 10 inspectors who have experience of quality judgment, ◎ "Gloss and color tone are very close to human hair", ○ "Gloss and color tone are closer to human hair" ○, "Gloss and color tone more than human hair""Slightlystrong" was evaluated as "A", "Gloss and color tone were both stronger than human hair" was evaluated as "x", and "Gloss and tone were both similar to human hair" was evaluated as "Good" or more.

Q. Combability The obtained bundle of monofilaments was used as a sample and brushed 100 times continuously using a commercially available hairbrush having 150 plastic combs arranged in a range of 4 cm in length and 8 cm in width. Regarding the resistance during brushing, and the occurrence of static electricity and entanglement after brushing, `` No resistance, no static electricity and no entanglement '' by a discussion of 10 inspectors with more than 5 years of experience in quality judgment ◎, ○: “There is almost no resistance, there is almost no static electricity or entanglement” ○, “There is a slight resistance, there is little static electricity or entanglement” △, and “There is considerable resistance, there is significant static electricity or entanglement” × ○ or more of “There is almost no resistance and there is almost no static electricity and no entanglement” was passed.

R. Heat resistance The obtained bundle of monofilaments was used as a sample and blown with a hand comb at 100 to 110 ° C for 5 minutes using a commercially available hair dryer. Regarding the blown sample, with regard to the damage and fusion of the hair tips, ◎, “No hair damage or fusion at all” by a collaborative meeting of 10 inspectors with more than 5 years of experience in quality judgmentを indicates that there is little damage to the tip and fusion, △ indicates that there is slight damage and fusion of the tip, and x indicates that the tip is severely damaged or fused. There is almost no wearing "or more.

Synthesis Example 1
To 100 parts by mass of cellulose (dissolving pulp made by Nippon Paper), 240 parts by mass of acetic acid and 67 parts by mass of propionic acid were added and mixed at 50 ° C. for 30 minutes. After cooling the mixture to room temperature, 172 parts by mass of acetic anhydride and 168 parts by mass of propionic anhydride cooled in an ice bath were added as esterifying agents, and 4 parts by mass of sulfuric acid was added as an esterification catalyst, followed by stirring for 150 minutes. An esterification reaction was performed. When the temperature exceeded 40 ° C. in the esterification reaction, the mixture was cooled in a water bath. After the reaction, a mixed solution of 100 parts by mass of acetic acid and 33 parts by mass of water was added as a reaction terminator over 20 minutes to hydrolyze excess anhydride. Thereafter, 333 parts by mass of acetic acid and 100 parts by mass of water were added, and the mixture was heated and stirred at 80 ° C. for 1 hour. After completion of the reaction, an aqueous solution containing 6 parts by mass of sodium carbonate was added, and the precipitated cellulose acetate propionate was separated by filtration, washed with water, and dried at 60 ° C. for 4 hours. The resulting cellulose acetate propionate had a degree of acetyl substitution of 2.0, a degree of propionyl substitution of 0.7 (total degree of substitution of cellulose ester of 2.7), and a weight average molecular weight (Mw) of 178,000. Was.

Example 1
82.0% by mass of cellulose acetate propionate produced in Synthesis Example 1, 17.9% by mass of polyethylene glycol having an average molecular weight of 600 (PEG600 manufactured by Sanyo Chemical Industries) as a plasticizer, and bis (2,6) as a phosphorus-based antioxidant 0.1% by mass of -di-t-butyl-4-methylphenyl) pentaerythritol diphosphite (PEP-36 manufactured by ADEKA) and 1.0% by mass of silica particles (Silysia 430 manufactured by Fuji Silysia) as inert particles. The mixture was kneaded at 230 ° C. using a shaft extruder, and cut to about 5 mm to obtain pellets (Mw 166,000) of the cellulose ester composition.

  The pellets of the cellulose ester composition obtained by the above method were vacuum-dried at 80 ° C. for 8 hours to adjust the water content to 200 ppm, and then introduced into a melt-spinning pack at a spinning temperature of 260 ° C. and discharged at 108 g / min. After spinning out from a spinneret having 10 holes (diameter 0.80 mm, hole length 2.4 mm) in a volume, cooled in a cooling bath filled with water at 20 ° C. and rotated at 750 m / min. It was taken up by one godet roller and wound up by a winder via a second godet roller rotating at the same speed as the first godet roller to obtain an undrawn yarn of cellulose ester monofilament.

  The obtained monofilament was cut into a length of 50 cm, and one end was bundled to prepare a bundle of monofilaments having a bundle diameter of 2 cm. The obtained bundle of monofilaments was scoured with hot water at 70 ° C. for 20 minutes, washed with running water at 25 ° C. for 30 minutes, and dried in a hot air dryer at 60 ° C. for 60 minutes. Subsequently, the bundle of monofilaments was alkali-treated at 60 ° C. for 30 minutes in a 1.5% by mass aqueous sodium hydroxide solution, washed with running water at 25 ° C. for 30 minutes, and washed at 60 ° C. for 30 minutes. It was dried in a hot air drier for 60 minutes.

  Using the bundle of monofilaments after the alkali treatment as a sample, the fiber properties of the monofilaments constituting the bundle of monofilaments and the artificial hair properties of the bundle of monofilaments were evaluated. Table 1 shows the results. The obtained monofilament had a core-sheath composite structure composed of a core portion made of cellulose ester and a sheath portion made of cellulose, and a concave portion was formed on the fiber surface. In addition, all of the evaluation items relating to the properties of the artificial hair were acceptable.

Examples 2 to 6, Comparative Example 1
A cellulose ester monofilament and a bundle of monofilaments were produced in the same manner as in Example 1 except that the addition amount of the silica particles was changed as shown in Table 1.

  Table 1 shows the evaluation results of the fiber properties of the monofilaments constituting the obtained monofilament bundle and the artificial hair properties of the monofilament bundle. In Examples 2 to 6, even when the addition amount of the silica particles was changed, it had a core-sheath composite structure including a core portion made of cellulose ester and a sheath portion made of cellulose, and a concave portion was formed on the fiber surface. I was In addition, all of the evaluation items relating to the properties of the artificial hair were acceptable. On the other hand, in Comparative Example 1, since no inert particles were added, although a core-sheath composite structure composed of a core portion made of cellulose ester and a sheath portion made of cellulose was used, a concave portion was formed on the fiber surface. Did not. In addition, since there was no unevenness on the fiber surface, the color depth was slightly lacking, and the gloss was stronger than human hair.

Examples 7 and 8
Bundles of cellulose ester monofilaments and monofilaments were produced in the same manner as in Example 4, except that the discharge rate during melt spinning was changed to 218 g / min in Example 7 and to 38 g / min in Example 8.

  Table 1 shows the evaluation results of the fiber properties of the monofilaments constituting the obtained monofilament bundle and the artificial hair properties of the monofilament bundle. Even when the fineness was changed, the fiber had a core-sheath composite structure composed of a core made of cellulose ester and a sheath made of cellulose, and a concave portion was formed on the fiber surface. In addition, all of the evaluation items relating to the properties of the artificial hair were acceptable.

Example 9
92.0% by mass of cellulose acetate propionate (CAP482-20 manufactured by Eastman Chemical) having an acetyl substitution degree of 0.2 and a propionyl substitution degree of 2.5 (total substitution degree of cellulose ester of 2.7), as a plasticizer 7.9% by mass of polyethylene glycol having an average molecular weight of 600 (PEG600 manufactured by Sanyo Chemical Industries), and bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite (manufactured by ADEKA) as a phosphorus-based antioxidant 0.1 mass% of PEP-36) and 10.0 mass% of silica particles (Silicia 430 manufactured by Fuji Silysia) as inert particles are kneaded at 230 ° C. using a twin-screw extruder, and cut to about 5 mm to obtain a cellulose ester. A pellet (Mw 161,000) of the composition was obtained.

  A cellulose ester monofilament and a bundle of monofilaments were produced in the same manner as in Example 4 except that the spinning temperature was 240 ° C., using the pellets of the cellulose ester composition obtained by the above-mentioned production method.

  Table 1 shows the evaluation results of the fiber properties of the monofilaments constituting the obtained monofilament bundle and the artificial hair properties of the monofilament bundle. The obtained monofilament had a core-sheath composite structure composed of a core portion made of cellulose ester and a sheath portion made of cellulose, and a concave portion was formed on the fiber surface. In addition, all of the evaluation items relating to the properties of the artificial hair were acceptable.

Example 10
Acetyl substitution degree is 1.0, butyryl substitution degree is 1.7 (cellulose ester total substitution degree is 2.7), 85.0 mass% of cellulose acetate butyrate (CAB381-20 manufactured by Eastman Chemical), average as plasticizer 14.9% by mass of polyethylene glycol having a molecular weight of 600 (PEG 600 manufactured by Sanyo Chemical Industries), and bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite (PEP manufactured by ADEKA) as a phosphorus-based antioxidant -36) 0.1 mass%, silica particles as inert particles (Silicia 430 manufactured by Fuji Silysia) 10.0 mass% are kneaded at 230 ° C. using a twin-screw extruder, and cut to about 5 mm to obtain a cellulose ester composition. A product pellet (Mw: 181,000) was obtained.

  A cellulose ester monofilament and a bundle of monofilaments were produced in the same manner as in Example 4, except that the spinning temperature was 250 ° C., using the pellets of the cellulose ester composition obtained by the above-mentioned production method.

  Table 1 shows the evaluation results of the fiber properties of the monofilaments constituting the obtained monofilament bundle and the artificial hair properties of the monofilament bundle. The obtained monofilament had a core-sheath composite structure composed of a core portion made of cellulose ester and a sheath portion made of cellulose, and a concave portion was formed on the fiber surface. In addition, all of the evaluation items relating to the properties of the artificial hair were acceptable.

Examples 11 to 17, Comparative Examples 2 to 5
A cellulose ester monofilament and a bundle of monofilaments were produced in the same manner as in Example 4, except that the alkali treatment conditions were changed as shown in Table 2.

  Table 2 shows the evaluation results of the fiber properties of the monofilaments constituting the obtained monofilament bundle and the artificial hair properties of the monofilament bundle. The monofilaments obtained in Examples 11 to 17 had a core-sheath composite structure including a core portion made of cellulose ester by an alkali treatment and a sheath portion made of cellulose, and concave portions were formed on the fiber surface. In addition, all of the evaluation items relating to the properties of the artificial hair were acceptable. In the monofilaments obtained in Comparative Examples 2 and 3, the hydrolysis of the cellulose ester completely progressed by the alkali treatment, and the monofilament was composed of only cellulose, and the fiber surface had convex portions instead of concave portions. In the artificial hair properties, it lacked aesthetics and slightly lacked in color depth. In Comparative Example 4, the alkali treatment did not proceed, and in Comparative Example 5, the alkali treatment was not performed. Therefore, the obtained monofilament was made of only cellulose ester, and the fiber surface had not convex portions but concave portions. I was The artificial hair had poor aesthetics, slightly lacking in color depth, and did not reach an acceptable level of heat resistance.

Comparative Examples 6 to 8
100.0% by mass of polyethylene terephthalate (IV = 0.66) and 10.0% by mass of silica particles (Silicia 430 manufactured by Fuji Silysia) as inert particles are kneaded at 280 ° C. using a twin-screw extruder, and the mixture is reduced to about 5 mm. By cutting, pellets of the polyethylene terephthalate composition were obtained.

  The polyethylene terephthalate composition pellets were vacuum-dried at 150 ° C. for 12 hours, the water content was adjusted to 50 ppm, and then introduced into a melt spinning pack at a spinning temperature of 290 ° C., and a die hole (diameter: (0.80 mm, hole length 2.4 mm) after spinning from a spinneret having 5 holes, cooled in a cooling bath filled with water at 20 ° C., and with a first godet roller rotating at 750 m / min. It was taken up and wound up by a winder via a second godet roller rotating at the same speed as the first godet roller to obtain an undrawn yarn of polyethylene terephthalate monofilament. The obtained undrawn yarn was drawn under the conditions of a first hot roller temperature of 90 ° C., a second hot roller temperature of 130 ° C., and a draw ratio of 4.0, to obtain a drawn yarn of polyethylene terephthalate monofilament.

  The obtained monofilament was cut into a length of 50 cm, and one end was bundled to prepare a bundle of monofilaments having a bundle diameter of 2 cm. The obtained bundle of monofilaments was scoured with hot water at 70 ° C. for 20 minutes, washed with running water at 25 ° C. for 30 minutes, and dried in a hot air dryer at 60 ° C. for 60 minutes. Subsequently, after alkali treatment under the conditions shown in Table 3, the substrate was washed with running water at 25 ° C. for 30 minutes and dried in a 60 ° C. hot air drier for 60 minutes.

  Using the bundle of monofilaments after the alkali treatment as a sample, the evaluation results of the fiber properties of the monofilaments constituting the bundle of monofilaments and the artificial hair properties of the bundle of monofilaments are shown in Table 3. In Comparative Example 6, since the alkali treatment was not performed, a convex portion was formed on the fiber surface of the obtained monofilament instead of a concave portion. Regarding the properties of artificial hair, the flexibility and moisture absorption / desorption properties were extremely low, and the aesthetics and deep color did not reach acceptable levels. Further, the combability was extremely poor due to the generation of static electricity. In Comparative Examples 7 and 8, the concave portion was formed on the surface of the monofilament fiber by the alkali treatment. Regarding the properties of artificial hair, the flexibility and moisture absorption / desorption properties were extremely low, and the aesthetics did not reach the acceptable level. Further, although concave portions are formed on the fiber surface and light is irregularly reflected, polyethylene terephthalate has a high refractive index and thus lacks color depth. Furthermore, since the friction band voltage was high, static electricity was easily generated, and the combability was extremely poor.

  Since the cellulosic fiber of the present invention has a texture close to that of human hair, and is excellent in deep color, matte and combability, it can be suitably used particularly for artificial hair. In addition, it can be suitably used as an auxiliary material for clothing such as a woven or knitted fabric for clothing, a core of a collar or a sleeve, and a living material such as a curtain.

Claims (4)

Cellulose type having an average fiber diameter of 25 to 500 μm, an average number of recesses per unit area on the fiber surface of 0.001 to 0.5 / μm ² , and an average diameter of the recesses of 0.5 to 30 μm Fibers , wherein the cellulosic fiber has a core-in-sheath composite structure including cellulose and a cellulose ester having at least a part of an acyl group having 3 to 18 carbon atoms, and a core portion contains the cellulose ester as a main component. And the sheath portion is a cellulosic fiber containing the above cellulose as a main component . Cellulose ester, cellulose fibers of claim 1 wherein the cellulose acetate propionate and / or cellulose acetate butyrate. The cellulosic fiber according to claim 1 or 2 , which is a monofilament. An artificial hair using the cellulosic fiber according to any one of claims 1 to 3 for at least a part thereof.