Artificial hair and process for producing the same

Abstract

To obtain artificial hair capable of retaining a form such as curl or wave made by a hair iron for a long time.SOLUTION: This artificial hair is made of a concentric core-sheath type composite fiber. The core component comprises a low melting point polyamide resin containing a crystalline region, and the sheath component comprises a high melting point polyamide resin containing a crystalline region. The core component comprises a low melting point polyester amide resin containing a crystalline region, and the sheath component comprises a high melting point polyester resin containing a crystalline region. This artificial hair is heated with a hair iron to melt the core component and collapse the crystalline region in the low melting point polyamide resin or low melting point polyester resin. When the hair is cooled while maintaining the curled state by the hair iron, the crystalline region is developed again in the core component and, therefore, the curl formed by the hair iron may be maintained over a long period of time.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to artificial hair that can be used as wigs, toupees, or hairpieces, and a method for producing the same, and in particular to artificial hair that can maintain curls, waves, etc., set by heat with a hair iron for a long period of time, and a method for producing the same. [Background technology]

[0002] Artificial hair has been used as a substitute for human hair. Known artificial hair is made of acrylic, polyester, or polyamide fibers. Recently, there has been a demand for artificial hair to be curled, wavy, or heat-set using a hair iron, just like human hair.

[0003] However, conventional artificial hair has been difficult to curl or wave with a hair iron. For this reason, Patent Document 1 proposes the use of core-sheath composite fibers as artificial hair. The core component has a softening point that is at least 20°C lower than the softening point of the sheath component, as measured by thermomechanical analysis according to JIS K 7196, and the core component is made of a substantially amorphous polymer that does not exhibit a melting point peak when heated at a heating rate of 10°C / min under a nitrogen atmosphere using differential thermal analysis (Patent Document, Claims 1 and 6). That is, the proposal proposes the use of core-sheath composite fibers as artificial hair. The core component is made of an amorphous polymer and the sheath component is made of a polymer that has a softening point higher than that of the core component. It explains that good hairstyles can be achieved by creating curls and heat-setting such artificial hair with hot curlers or the like (Patent Document 1, page 24, lines 14-18).

[0004] However, the artificial hair described in Patent Document 1 has a core component that is an amorphous polymer and does not have a crystalline region, so it has poor shape retention after heat setting, and it is difficult to maintain a hairstyle that has been heat set with a hair iron for a long time.

[0005] [Patent Document 1] International Publication No. 97 / 028299 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide artificial hair that can maintain the curls, waves, etc. created with a hair iron for a long period of time. [Means for solving the problem]

[0007] The present invention solves the above-mentioned problems by employing a low-melting-point polyamide resin or low-melting-point polyester resin with crystalline regions as the core component of artificial hair made of concentric sheath-core composite fibers. That is, the present invention relates to artificial hair made of concentric sheath-core composite fibers, characterized in that the core component is a low-melting-point polyamide resin containing crystalline regions or a low-melting-point polyester resin containing crystalline regions, and when the core component is the low-melting-point polyamide resin, the sheath component is made of a high-melting-point polyamide resin with crystalline regions having a melting point higher than that of the low-melting-point polyamide resin, or when the core component is the low-melting-point polyester resin, the sheath component is made of a high-melting-point polyester resin with crystalline regions having a melting point higher than that of the low-melting-point polyester resin, and a method for producing the artificial hair.

[0008] The artificial hair according to the present invention is formed of concentric sheath-core composite fibers having a substantially circular cross section. Eccentric sheath-core composite fibers are undesirable because they are prone to crimping when heated with a hair iron due to the difference in thermal shrinkage between the core component and the sheath component. The present invention employs concentric sheath-core composite fibers that are less likely to crimp when heated. The diameter of the artificial hair according to the present invention is approximately 0.05 to 0.15 mm.

[0009] The core component is made of a low-melting-point polyamide resin containing crystalline regions or a low-melting-point polyester resin containing crystalline regions. The proportion of crystalline regions (crystallinity) is approximately 10 to 40%. Such polyamide resins or polyester resins containing crystalline regions exhibit a clear melting peak in a DSC curve measured by differential scanning calorimetry. When the core component is a low-melting-point polyamide resin, the sheath component is made of a high-melting-point polyamide resin having crystalline regions with a melting point higher than that of the low-melting-point polyamide resin. Polyamide resins are used for the core component and sheath component to increase the affinity between the core component and the sheath component and make them less likely to peel. Examples of high-melting-point polyamide resins that can be used include polyamide 6 (nylon 6: melting point approximately 225°C), polyamide 66 (nylon 66: melting point approximately 265°C), polyamide 46 (nylon 46: melting point approximately 295°C), and polyamide 12 (nylon 12: melting point approximately 176°C). On the other hand, the low-melting-point polyamide resin may have a lower melting point than the high-melting-point polyamide resin. Since the melting points of the high-melting-point polyamide resin and the low-melting-point polyamide resin are relative, for example, polyamide 6 (melting point: approximately 225°C) may be used as the low-melting-point polyamide resin, and polyamide 66 (melting point: approximately 265°C) may be used as the high-melting-point polyamide resin. Alternatively, the low-melting-point polyamide resin may be a copolymer polyamide resin obtained by copolymerizing polyamide 6 or polyamide 66 with another type of polyamide, resulting in a melting point of 100°C to 200°C. Because the heating temperature of a hair iron is generally approximately 100°C to 250°C, it is preferable to use a copolymer polyamide resin whose melting point is lowered by copolymerizing another type of polyamide as the low-melting-point polyamide resin.

[0010] Furthermore, when the core component is a low-melting-point polyester resin, the sheath component is made of a high-melting-point polyester resin having a crystalline region with a melting point higher than that of the low-melting-point polyester resin. The reason why polyester resins are used for the core component and the sheath component is to increase the affinity between the core component and the sheath component and make them less likely to peel off. Polyethylene terephthalate resin (melting point: approximately 265°C) is generally used as the high-melting-point polyester resin. And, as the low-melting-point polyester resin, a copolymer polyester having a melting point of 100°C to 200°C is used, which is obtained by copolymerizing polyethylene terephthalate with other acid components and / or diol components. Examples of the other acid components and / or diol components to be copolymerized include isophthalic acid and butanediol.

[0011] The outer peripheral surface of the sheath component of the artificial hair according to the present invention is preferably uneven. This is because unevenness on the outer peripheral surface of the sheath component can reduce the gloss of the artificial hair surface, making it more similar to the feel of human hair. To form unevenness, for example, a method can be used in which a soluble resin is mixed into the sheath component in advance and the soluble resin is eluted. An alkali-soluble polyester resin that dissolves in an alkaline aqueous solution is generally used as the soluble resin. Furthermore, a method in which inorganic fine particles are present in the sheath component can also be employed. When inorganic fine particles are present in the sheath component, some of the inorganic fine particles protrude from the sheath component surface, forming unevenness. Conventionally known inorganic fine particles can be used as the inorganic fine particles, and those with a particle size of approximately 0.001 to 5 μm can be used. Specifically, titanium oxide fine particles can be used. Furthermore, the method of using a soluble resin and the method of using inorganic fine particles can be used in combination. The artificial hair according to the present invention can be dyed in any color. Since Japanese people generally have black hair, it is preferable that the hair is dyed black, dark brown, dark brown, brown, or brownish brown.

[0012] Next, a method for manufacturing artificial hair according to the present invention will be described. First, a crystalline low-melting-point polyamide resin or a crystalline low-melting-point polyester resin is prepared as the core component. The aforementioned polyamide 12 or copolymer polyamide resin is preferably used as the crystalline low-melting-point polyamide resin. Furthermore, a copolymer polyester resin copolymerized with isophthalic acid, butanediol, or the like is preferably used as the crystalline low-melting-point polyester resin. Meanwhile, a crystalline high-melting-point polyamide resin having a melting point higher than that of the crystalline low-melting-point polyamide resin or a crystalline high-melting-point polyester resin having a melting point higher than that of the crystalline polyester resin is prepared as the sheath component. Polyamide 6 or polyamide 66 is preferably used as the high-melting-point polyamide resin. Furthermore, polyethylene terephthalate is preferably used as the high-melting-point polyester resin.

[0013] When a low-melting-point polyamide resin is used as the core component, a high-melting-point polyamide resin is used as the sheath component, and a concentric sheath-core conjugate continuous fiber is obtained by a conventionally known conjugate melt spinning method. When a low-melting-point polyester resin is used as the core component, a high-melting-point polyester resin is used as the sheath component, and a concentric sheath-core conjugate continuous fiber is obtained by a conventionally known conjugate melt spinning method. In this case, it is preferable to incorporate a soluble resin or inorganic fine particles into the sheath component. The amount of soluble resin contained in the sheath component is approximately 10 to 40% by mass. The amount of inorganic fine particles contained in the sheath component is approximately 0.1 to 1% by mass. The concentric sheath-core conjugate continuous fiber obtained by the conjugate melt spinning method is then drawn. Drawing is also performed by a conventionally known method, and is generally performed once or multiple times in a hot water bath or under dry heat. The draw ratio is preferably approximately 2 to 5 times. Drawing to this extent allows crystalline regions to appear in the core and sheath components of the concentric sheath-core conjugate continuous fiber.

[0014] When a soluble resin is contained in the sheath component, the soluble resin is generally eluted after the drawing process. When an alkali-soluble polyester resin is used as the soluble resin, the concentric sheath-core conjugate continuous fiber that has been drawn can be immersed in an alkaline aqueous solution. It is also common for the concentric sheath-core conjugate continuous fiber to be subjected to a dyeing process in which it is dyed black or the like. The concentric sheath-core conjugate continuous fiber obtained in this manner can be cut to any length to form artificial hair.

[0015] The artificial hair according to the present invention can be heat-set satisfactorily by the following method. First, the artificial hair according to the present invention is heated with a hair iron to melt the core component made of a low-melting-point polyamide resin or a low-melting-point polyester resin. At this time, the sheath component made of a high-melting-point polyamide resin or a high-melting-point polyester resin is not melted. Melting the sheath component is undesirable because it destroys the cross-sectional shape of the artificial hair, which has a substantially circular cross section, and causes the texture of human hair to be lost. The melting of the core component causes the crystalline regions to collapse, but the shape created by the hair iron, such as curls or waves, is retained. The artificial hair is then cooled while maintaining this shape. Cooling is preferably performed at room temperature. Gradual cooling, rather than rapid cooling, facilitates the crystallization of the core component. This cooling re-emerges the crystalline regions, allowing the shape stability of curls, waves, etc. to be maintained for a long period of time. [Effects of the Invention]

[0016] The artificial hair according to the present invention is a concentric core-sheath type composite fiber, and the core component is a low-melting point polyamide resin or low-melting point polyester resin containing a crystalline region, so that the shape created with a hair iron can be maintained for a long time. [Example]

[0017] Example 1 A crystalline low-melting-point polyamide resin ("Platamid H005" manufactured by Arkema) with a melting point of 115°C was prepared as the core component. Meanwhile, polyamide 6 with a melting point of 225°C was used as the high-melting-point polyamide resin. This polyamide 6 was mixed with an alkali-soluble polyester resin in a mass ratio of polyamide 6:alkali-soluble polyester resin = 80:20 to prepare a polyamide resin composition as the sheath component. The alkali-soluble polyester was obtained by copolymerizing 48 mol% of terephthalic acid, 2 mol% of isophthalic acid, 38 mol% of ethylene glycol, and 12 mol% of polyethylene glycol.

[0018] 50 parts by mass of the prepared core component and 50 parts by mass of the sheath component were fed into a conjugate melt spinning apparatus, and a concentric sheath-core composite yarn was extruded from a conjugate melt spinning hole (hole diameter: 0.9 mm) at a spinning temperature of 270°C. The composite yarn was then cooled with water at 30°C, and subsequently subjected to a first-stage drawing at a draw ratio of 3.63 times in a 90°C water bath, followed by a second-stage drawing at a draw ratio of 1.13 times in a dry heater at 100°C. The yarn was then subjected to a relaxation heat treatment at a temperature of 100°C to obtain a concentric sheath-core composite continuous fiber. The concentric sheath-core composite continuous fiber had a substantially circular cross section and a diameter of 0.110 mm.

[0019] A concentric sheath-core composite continuous fiber was wound into a skein with a skein length of 113 cm and a wound weight of 250 g using a skein winding machine (Kyoritsu Machinery Manufacturing Co., Ltd.). This skein was then loaded into a package dyeing machine (Hisaka Works, Ltd.) and the alkali-soluble polyester resin in the sheath component was eluted using 40 g / L of sodium hydroxide solution at a bath ratio of 1:30, a temperature of 95°C, and a time of 90 minutes. The fiber was then dehydrated and washed with water, and subsequently dyed using a black dye (DyStar Japan's "Mitsui Nylon Black") at 5% omf, 0.2 cc / L of acetic acid, and a dyeing assistant (Marubishi Yuka Kogyo's "Levelan NKD") at a bath ratio of 1:30, a temperature of 100°C, and a time of 30 minutes. The fiber was then dehydrated and washed with water to obtain a black concentric sheath-core composite continuous fiber.

[0020] The concentric core-sheath composite continuous fibers obtained in this manner were cut to a length of 60 cm to obtain artificial hair composed of concentric core-sheath composite fibers. Approximately 750 of these artificial hairs were bundled together to form an artificial hair bundle, and then a hair iron (TESCOM "TW553A") was used, set to a temperature of 150°C, and the clip on the curling iron was opened. The artificial hair bundle was wrapped around the hair once, and the clip was closed and held for 15 seconds. The clip was then opened, and the artificial hair bundle was carefully removed from the hair iron while maintaining the curled shape. The artificial hair bundle was then left to cool at room temperature for 30 seconds and heat-set. The curled artificial hair of the present invention exhibited excellent curl retention over a long period of time.

Claims

1. Artificial hair made of concentric core-sheath type composite fibers, the core component of which is a low-melting-point polyamide resin containing a crystalline region or a low-melting-point polyester resin containing a crystalline region, When the core component is the low-melting-point polyamide resin, the sheath component is made of a high-melting-point polyamide resin having a crystalline region with a melting point higher than that of the low-melting-point polyamide resin, Alternatively, when the core component is the low-melting polyester resin, the sheath component is made of a high-melting polyester resin having a crystalline region with a melting point higher than that of the low-melting polyester resin.

2. 2. The artificial hair according to claim 1, wherein the concentric core-sheath type composite fiber has an uneven surface.

3. 2. The artificial hair according to claim 1, wherein the sheath component contains inorganic fine particles.

4. A wig, hairpiece or hairpiece comprising the artificial hair according to any one of claims 1 to 3.

5. A method for heat-setting artificial hair, comprising heating the artificial hair according to claim 1 with a hair iron to melt the core component, thereby collapsing the crystalline regions in the low-melting polyamide resin or low-melting polyester resin and forming a predetermined shape, and then cooling the artificial hair while maintaining the predetermined shape, thereby causing the crystalline regions to appear again in the core component.

6. The core component is a crystalline low-melting polyamide resin or a crystalline low-melting polyester resin, When the core component is the crystalline low-melting point polyamide resin, the sheath component is a crystalline high-melting point polyamide resin having a melting point higher than that of the crystalline low-melting point polyamide resin. After obtaining the concentric core-sheath type conjugate continuous fiber, Alternatively, when the core component is the crystalline low-melting point polyester resin, the sheath component is a crystalline high-melting point polyester resin having a melting point higher than that of the crystalline low-melting point polyester resin, and then a concentric core-sheath type conjugated continuous fiber is obtained, A method for producing artificial hair made of concentric sheath-core composite fibers, characterized in that the concentric sheath-core composite continuous fibers are stretched to produce crystalline regions in the core component and the sheath component.

7. 7. A method for producing artificial hair comprising concentric sheath-core composite fibers according to claim 6, wherein a soluble resin is added to the sheath component to obtain concentric sheath-core composite continuous fibers, and then the soluble resin is eluted.

8. 8. A method for producing artificial hair comprising concentric core-sheath type composite fibers according to claim 7, wherein the soluble resin is an alkali-soluble polyester resin.

9. A method for producing artificial hair made from the concentric core-sheath type composite fiber according to any one of claims 6 to 8, further comprising a dyeing step.