ORGANISATION AFRICAINE DE LA PROPRIETE INTELLECTUELLE

Transcription

1 19 ORGANISATION AFRICAINE DE LA PROPRIETE INTELLECTUELLE 11 N Inter. CI. A41G 3/00; A41G 5/00; C08L 63/00C08L 67/02; D01F 6/92 FASCICULE DEBREVET D INVENTION Numéro de dépôt: Titulaire(s) : Date de dépôt :07/02/2014 KANEKA CORPORATION, 3-18, Nakanoshima 2-chome, Kita-ku, OSAKA-SHI, Osaka (JP) 30 Priorité(s) : JP n JP du 30/09/ Inventeur(s) : YORIZANE Mika (JP) HIGAMI Tomokazu (JP) KAWAMURA Kohei (JP) HASHIMOTO Tomomichi (JP) 24 Délivré le :31/10/ Mandataire : Cabinet ÉKÉMÉ LYSAGHT SARL, B.P. 6370, YAOUNDE (CM). 45 Publié le : Titre :Polyester-based fiber for artificial hair, fiber bundle for hair, and hair ormament product including the same. 57 Abrégé : The present invention provides a polyester-based fiber for artificial hair having a high level of flame retardante and excellent color development, a fiber bundle for hair, and a hair ornament product including the polyester-based fiber for artificial hair. The polyester-based fiber for artificial hair of the present invention includes a brominated epoxy flame retardant and at least one polyester resin selected from the group consisting of polyalkylene terephthalate and a copolymerized polyester containing polyalkylene terephalate an the main component. The brominated epoxy flame retardant dispersed in the polyester resin has an average diagonal width of 0.05 μm or less in a cross section of the fiber parallel to the fiber axis direction. In the polyester-based fiber for artificial hair, it is preferable that polyester resin has a larger melt viscosity than that of the brominated epoxy flame retardant at 280 C. Further, it is preferable that the fiber has a viscosity of 2,000 to 8,000 poise at a shear rate of 50 mm/min when melted at 280 C. O.A.P.I. B.P. 887, YAOUNDE (Cameroun) Tel. (237) Fax: (237) Site web: oapi@oapi.int

2 Kaneka Corporation POLYESTER-BASED FIBER FOR ARTIFICIAL HAIR, FIBER BUNDLE FOR HAIR, AND HAIR ORNAMENT PRODUCT INCLUDING THE SAME BACKGROUND OF THE INVENTION 5 1. Field of the Invention The present invention relates to a polyesterbased fiber for artificial hair that can be used as an alternative to human hair, and to a fiber bundle for hair and a hair ornament product including the polyesterbased fiber for artificial hair. More specifically, the present invention relates to a polyester-based fiber for artificial hair 10 having a high level of flame retardance and excellent color development, and to a fiber bundle for hair and a hair ornament product induding the polyesterbased fiber for artificial hair. 2. Description of Related Art 15 Conventionally, human hair has been used for hair ornament products such as hairpieces, hair wigs, hair extensions, hair bands, and doll hair. However, in place of human hair, fibers for artificial hair are gaining importance in recent years as it has become more and more difficult to obtain human hair. For example, as materials for fibers for artificial hair, the use of polyesterbased fibers having as the main component 20 polyethylene terephthalate, a material with excellent heat resistance, has been proposed. When using the polyesterbased fibers as fibers for artificial hair, flame retardance is also required of them from the safety standpoint. Thus, studies have been conducted to impart flame retardance to the polyesterbased fibers. For example, JP A, JP A and WO 2005/ propose flame-retarding 25 polyester-based fibers, each of which is obtained by including a brominated epoxy flame retardant in a polyesterbased fiber. SUMMARY OF THE INVENTION The flame-retarding polyester-based fibers described in the prior art 30 documents do have improved flame retardance because they contain a brominated epoxy flame retardant, but they may have poor color development. In order to solve the conventional problem discussed above, the present 1

3 invention provides a polyesterbased fiber for artificial hair having a high level of flame retardance and excellent color development, a fiber bundle for hair and a hair ornament product induding the polyesterbased fiber for artificial hair. The present invention relates to a polyesterbased fiber for artificial hair, 5 including a polyester resin and a brominated epoxy flame retardant. The polyester resin is at least one resin selected from the group consisting of polyalkylene terephthalate and a copolymerized polyester containing polyalkylene terephthalate as the main component, and the brominated epoxy flame retardant dispersed in the polyester resin has an average diagonal width of 0.05 pm or less in a cross section of 10 the fiber parallel to the fiber axis direction. In the polyesterbased fiber for artificial hair, it is preferable that the polyester resin has a larger melt viscosity than that of the brominated epoxy flame retardant at 280 C. Further, when melted at 280 C, the fiber preferably has a viscosity of 2,000 to 8,000 poise at a shear rate of 50 mm/rain. It is preferable that the polyesterbased 15 fiber for artificial hair includes 0.5 to 5 parts by weight of a glycidyl group-containing vinyl-based polymer with respect to 100 parts by weight of the polyester resin. It is preferable that the glycidyl group-containing vinyl-based polymer includes 1 to 20 wt% of glycidyl methacrylate with respect to the total weight of the glycidyl group-containing vinyl-based polymer. It is preferable that the polyesterbased fiber 20 for artificial hair further includes 0.2 to 3 parts by weight of bydrotalcite with respect to 100 parts by weight of the polyester resin. The present invention also relates to a fiber bundle for hair, which includes the polyesterbased fiber for artificial hair and at least one fiber selected from the group consisting of human hair, animal hair, a polyvinyl chloride-based fiber, a 25 modacrylic fiber, a polyamide-based fiber, a polyolefm-based fiber, a regenerated protein fiber, and other polyesterbased fiber. The present invention also relates to a hair ornament product including the polyesterbased fiber for artificial hair. The hair ornament product further may include at least one fiber selected 30 from the group consisting of human hair, animal hair, a polyvinyl chloride-based fiber, a modacrylic fiber, a polyamide-based fiber, a polyolefin-based fiber, a regenerated protein fiber, and other polyesterbased fiber. 641,,,P? 2

4 In the polyester-based fiber for artificial hair including the polyester resin and the brominated epoxy flame retardant of the present invention, the brominated epoxy flame retardant dispersed in the polyester resin has an average diagonal width of 0.05 tim or less in the cross section of the fiber parallel to the fiber axis direction. Thus, the 5 polyester-based fiber for artificial hair, the fiber bundle for hair and the hair ornament product provided by the present invention have a high level of flame retardance and excellent color development. BRIEF DESCRIPTION OF THE DRAWINGS 10 FIG. 1 is a diagram schematically showing the diagonal width of the brominated epoxy flame retardant in the present invention. DETAILED DESCRIPTION OF THE INVENTION The present inventors have conducted numerous studies to solve the above 15 problem, and they found that a polyester-based fiber for artificial hair including a polyester resin and a brominated epoxy flame retardant can have excellent color development while maintaining a high level of flame retardance when the brominated epoxy flame retardant dispersed in the polyester resin has an average diagonal width of 0.05 pm or less. As a result, the present inventors have reached the present 20 invention. Further, they also found that the brominated epoxy flame retardant dispersed in the polyester resin of the polyester-based fiber for artificial hair can have an average diagonal width of 0.05 pm or less when the polyester resin has a larger melt viscosity than that of the brominated epoxy flame retardant at 280 C and the fiber has a viscosity of 2,000 to 8,000 poise at a shear rate of 50 ram/min when melted 25 at 280 C. The polyester-based fiber for artificial hair of the present invention is composed of a polyester resin composition containing a polyester resin, a brominated epoxy flame retardant, and the like. The brominated epoxy flame retardant dispersed in the polyester resin has an 30 average diagonal width of 0.05 [tm or less in a cross section of the polyester-based fiber for artificial hair parallel to the fiber axis direction. The lower limit of the average diagonal width of the brominated epoxy flame retardant is preferably tim or vt, 3

5 more, and more prefers* 0.01 gra or more. The upper limit of the average diagonal width of the brominated epoxy flame retardant is preferably 0.04 gra or less. In the present invention, the diagonal width of the brominated epoxy flame retardant in the cross section of the fiber parallel to the fiber axis direction refers to the maximum 5 length of the brominated epoxy flame retardant in a direction perpendicular to the fiber axis direction in the cross section parallel to the fiber axis direction. Specifically, as shown in FIG. 1, in a cross section 100 parallel to a fiber axis direction D, the maximum length W of a brominated epoxy flame retardant 20 (dispersed in a polyester resin 10) in a direction perpendicular to the fiber axis direction D is the 10 diagonal width. And the average diagonal width of the brominated epoxy flame retardant in the cross section of the polyesterbased fiber for artificial hair parallel to the fiber axis direction is obtained by averaging the diagonal widths of the brominated epoxy flame retardant present per 360 itm 2 of the fiber. In the polyesterbased fiber for artificial hair, the brominated epoxy flame 15 retardant dispersed in the polyester resin can be identified by observing the cross section of the fiber parallel to the fiber Euds direction with a scanning electron microscope (SEM) and the like. Further, in the present invention, the average diagonal width of the brominated epoxy flame retardant can be calculated by measuring the diagonal width of the brominated epoxy flame retardant in the cross 20 section of the fiber parallel to the fiber axis direction using an SEM image of the cross section of the polyesterbased fiber for artificial hair parallel to the fiber axis direction. The cross section of the polyesterbased fiber for artificial hair parallel to the fiber axis direction can be produced, e.g., by cross section preparation (ion milling) using a cross section polisher (CP). The morphological observation of the cross section of the fiber 25 parallel to the fiber axis direction can be carried out with a field emission scanning electron microscope (FE-SEM) ("ULTRA plus" manufactured by Carl Zeiss Co., Ltd.) at an acceleration voltage of 2 kv. Since a composition image of a sample depends on the average atomic number, the image becomes bright in a portion of the sample that includes heavy elements and becomes dark in a portion of the sample that includes 30 light elements. The polyester resin is at least one resin selected from the group consisting of polyalkylene terephthalate and a copolymerized polyester containing polyalkylene tv-- 4

6 terephthalate as the main component. The polyalkylene terephthalate is not particularly limited and may be, e.g., polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, or polycydohexane dimethylene terephthalate. The copolymerized polyester containing polyalkylene terephthalate as 5 the main component is not particularly limited and may be, e.g., a copolymerized polyester containing polyalkylene terephthalate (such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, or polycyclohexane climethylene terephthalate) as the main component and other copolymerizable components. In the present invention, the term "math component" means 10 "containing the component in an amount of 50 mol% or more". Thus, the "copolymerized polyester containing polyalkylene terephthalate as the main component" refers to the copolymerized polyester containing 50 mol% or more of polyalkylene terephthalate. The "copolymerized polyester containing polyalkylene terephthalate as the main component" contains preferably 60 mol% or more, more 15 preferably 70 mol% or more, and even more preferably 80 mol% or more of polyalkylene terephthalate. Examples of the other copolymerizable components include the following: polycarboxylic acids such as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid, trimellitic acid, 20 pyromellitic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic add, sebacic add, and dodecanedioic acid, and their derivatives; dicarboxylic acids including a sulfonic acid salt such as 5-sodiumsulfoisophthalic acid and dihydroxyethyl 5-sodiumsulfoisophthalate, and their derivatives; 1,2-propanediol; 1,3-propanediol; 1,4-butanediol; 1,6-hexanediol; neopentyl glycol; 1,4-cydohexanedimethanol; 25 diethylene glycol; polyethylene glycol; trimethylolpropane; pentaerytinitol; 4-hydroxybenzoic acid; and s-caprolactone. The specific examples of the copolymerized polyester containing polyalkylene terephthalate as the main component include a copolymerized polyester obtained by copolymerization of polyethylene terephthalate as the main component with one 30 compound selected from the group consisting of ethylene glycol ether of bisphenol A, 1,4-cyclohexanedimethanol, isophthnlic acid, and dihydroxyethyl 5-sodiumsulfoisophthalate. 5

7 The polyalkylene terephthalate and the copolymerized polyester containing polyalkylene terephthalate as the main component may be used individually or in combinations of two or more. In particular, it is preferable that polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, a 5 copolymerized polyester obtained by copolymerization of polyethylene terephthalate as the main component with ethylene glycol ether of bisphenol A, a copolymerized polyester obtained by copolymerization of polyethylene terephthalate as the main component with 1,4-cyclohexaneclimethanol, a copolymerized polyester obtained by copolymerization of polyethylene terephthalate as the main component with 10 isophthalic acid, and a copolymerized polyester obtained by copolymerization of polyethylene terephthalate as the main component with clihydroxyethyl 5-soditunsulfoisophthalate are used individually or in combinations of two or more. The brorainated epoxy flame retardant is not particularly limited. As its raw material, a brominated epoxy flame retardant having an epoxy group or 15 tribromophenol at the end of the molecule may be used. Specifically, any compound containing a structure represented by the following general formula (1) in the molecule may be used as the brominated epoxy flame retardant. [Chemical Formula 1] Br Cu 1 CH3 Br OCH2CHCH 2 (1) 20 In the general formula 1, m is 1 to OH Specifically, the compounds represented by the general formula (1) may include compounds represented by the following general formulas (2) to (4). [Chemical Formula 21 Br CH CHCH 2 OCH 2CHCH2 OH 0- CH2 CH-CH2 (2) 25 6

8 [Chemical Formula 3] CH2- CHCH, 2 - Br [Chemical Formula 4] - Br Br OCH2CHCH2 0-CH2 CH-CH2 OH -m Br CH3 OH 0 (4) ry y is 0 to 5. In the general formulas (2) to (4), m is 1 to 1,000, R 1 is C1-C10 alkyl group, and 5 In the present invention, a brominated epoxy flame retardant whose molecule end has any of the aforementioned structures is used as a raw material. However, after melt kneading and/or melt spinning (i.e., in the fiber), the structure of the brominated epoxy flame retardant is not particularly limited, and the molecule end may be replaced with an epoxy group, a hydroxyl group, a phosphoric acid group or a 10 phosphonic acid group or the molecular end may be bonded to the polyester resin through an ester group. The above brominated epoxy flame retardants may be used individually or in combination of two or more. It is preferable that the polyester-based fiber for artificial hair includes 5 to parts by weight of the brominated epoxy flame retardant with respect to 100 parts by weight of the polyester resin. The lower limit of the brominated epoxy flame retardant content is more preferably 6 parts by weight or more with respect to 100 parts by weight of the polyester resin. The upper limit of the brominated epoxy flame retardant content is more preferably 30 parts by weight or less, and even more 20 preferably 25 parts by weight or less with respect to 100 parts by weight of the polyester resin. When the brominated epoxy flame retardant content is within the above ranges, the polyester-based fiber for artificial hair has excellent flame oc- 7 R1 Bry

9 retardance, color development, and spirmability. In the polyester-based fiber for artificial hair, it is preferable that the polyester resin has a larger melt viscosity at 280 C (hereinafter, simply referred also to as melt viscosity) than that of the brominated epoxy flame retardant. When the brominated 5 epoxy flame retardant has a smaller melt viscosity than that of the polyester resin, the brominated epoxy flame retardant does not agglomerate, and can be dispersed in the polyester resin while having an average diagonal width of 0.05 pm or less in the cross section of the polyester-based fiber for artificial hair parallel to the fiber axis direction. In terms of preventing the brominated epoxy flame retardant in the polyester resin 10 from agglomerating so that it can be dispersed more easily, the melt viscosity of the polyester resin is larger than that of the brominated epoxy flame retardant by preferably 1,000 poise or more, and more preferably 1,500 poise or more. Further, the difference between the melt viscosity of the polyester resin and that of the brominated epoxy flame retardant is preferably 6,000 poise or less, and more preferably 5, poise or less. In terms of making the polyester-based fiber for artificial hair easily adjustable such that the fiber has a viscosity of 2,000 to 8,000 poise at a shear rate of 50 mm/min when melted at 280 C, the melt viscosity of the polyester resin is preferably 2,000 to 8,000 poise. The lower limit of the melt viscosity of the polyester resin is more preferably 3,000 poise or more. Further, the upper limit of the melt 20 viscosity of the polyester resin is more preferably 7,000 poise or less. The lower limit of the melt viscosity of the brominated epoxy flame retardant is preferably 500 poise or more, and more preferably 800 poise or more. Further, the upper limit of the melt viscosity of the brominated epoxy flame retardant is preferably 3,200 poise or less, and more preferably 3,000 poise or less. 25 The polyester-based fiber for artificial hair includes preferably 0.5 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, and even more preferably 0.5 to 2 parts by weight of a glycidyl group-containing vinyl-based polymer with respect to 100 parts by weight of the polyester resin. The glycidyl group-containing vinyl-based polymer acts as a thickener for the polyester resin. By making the melt viscosity of 30 the polyester resin larger than the melt viscosity of the brominated epoxy flame retardant, the dispersibility of the brominated epoxy flame retardant in the polyester resin can be improved, which results in a further improvement in the color 8

10 development of the polyester-based fiber for artificial hair. The glycidyl group-containing vinyl-based polymer is not particularly limited as long as it is a polymer capable of increasing the melt viscosity of the polyester resin. The glycidyl group-containing vinyl-based polymer may be, e.g., a polymer containing 5 glycidyl methacrylate. In terms of improving the color development of the polyester-based fiber for artificial hair and suppressing fiber fusion at the same time, it is preferable that the glycidyl group-containing vinyl-based polymer contains 1 to 20 wt% of glycidyl methacrylate with respect to the total weight of the glycidyl group-containing vinyl-based polymer. The lower limit of the glycidyl methacrylate 10 content in the glycidyl group-containing vinyl-based polymer is more preferably 2 wt% or more, and even more preferably 3 wt% or more. The upper limit of the glycidyl methacrylate content in the glycidyl group-containing vinyl-based polymer is more preferably 15 wt% or less, and even more preferably 10 wt% or less. It is preferable that the polyester-based fiber for artificial hair includes 0.2 to 3 15 parts by weight of hydrotalcite with respect to 100 part by weight of the polyester resin. The lower limit of the hydrotalcite content is preferably 0.5 parts by weight or more with respect to 100 part by weight of the polyester resin. The upper limit of the hydrotalcite content is more preferably 3 parts by weight or less, and even more preferably 2 parts by weight or less with respect to 100 parts by weight of the polyester 20 resin. Hydrotalcite acts as a bromine absorbent, and absorbs bromine resulting from thermal decomposition of the brominated epoxy flame retardant. Thus, it is possible to prevent the formation of a gel by polymerization of epoxy groups of the brominated epoxy flame retardant due to bromine, and by extension to suppress fiber fusion. In terms of flame retardance, the polyester-based fiber for artificial hair may 25 further include flame retardant auxiliaries. For example, antimony compounds may be used as flame retardant auxiliaries. Examples of antimony compounds include antimony oxides such as antimony trioxide, antimony tetroxide, and antimony pentoxide, and metal salts of antimonic acid such as sodium antimonate, and potassium antimonate. It is preferable that the antimony compound content is 0.5 to parts by weight with respect to 100 parts by weight of the polyester resin. The lower limit of the antimony compound content is more preferably 1 part by weight or more, and even more preferably 1.5 parts by weight or more with respect to 100 part, v, 9

11 by weight of the polyester resin. The upper limit of the antimony compound content is more preferably 7 parts by weight or less, and even more preferably 5 parts by weight or less with respect to 100 part by weight of the polyester resin. The polyester-based fiber for artificial hair may include a variety of additives 5 such as a flame retardant other than the brominated epoxy flame retardant, a flame retardant auxiliary other than the antimony compound, a heat-resistant agent, a stabilizer, a fluorescent agent, an antioxidant, and an antistatic agent as needed as long as they do not interfere with the effects of the present invention. The polyester-based fiber for artificial hair of the present invention can be 10 produced by melt spinning a polyester resin composition containing the polyester resin and the brominated epoxy flame retardant using a general melt spinning method. It is preferable that the polyester resin composition contains 5 to 40 parts by weight of the brominated epoxy flame retardant with respect to 100 parts by weight of the polyester resin. The lower limit of the brominated epoxy flame retardant content 15 is more preferably 6 parts by weight or more with respect to 100 parts by weight of the polyester resin. The upper limit of the brominated epoxy flame retardant content is more preferably 30 parts by weight or less, and even more preferably 25 parts by weight or less with respect to 100 parts by weight of the polyester resin. Further, the polyester resin composition contains preferably 0.5 to 5 parts by weight, more 20 preferably 0.5 to 3 parts by weight, and even more preferably 0.5 to 2 parts by weight of the glycidyl group-containing vinyl-based polymer with respect to 100 parts by weight of the polyester resin. Further, it is preferable that the polyester resin composition contains 0.2 to 3 parts by weight of hydrotalcite with respect to 100 parts by weight of the polyester resin. The lower limit of the hydrotalcite content is more 25 preferably 0.5 parts by weight or more with respect to 100 parts by weight of the polyester resin. The upper limit of the hydrotalcite content is more preferably 3 parts by weight or less, and even more preferably 2 parts by weight or less with respect to 100 parts by weight of the polyester resin. Further, it is preferable that the polyester resin composition contains 0.5 to 10 parts by weight of the antimony compound with 30 respect to 100 parts by weight of the polyester resin. The lower limit of the antimony compound content is more preferably 1 part by weight or more, and even more preferably 1.5 parts by weight or more with respect to 100 parts by weight of the 10

12 polyester resin. The upper limit of the antimony compound content is more preferably 7 parts by weight or less, and even more preferably 5 parts by weight or less with respect to 100 parts by weight of the polyester resin. The polyester resin composition can be obtained by thy blending the 5 above-described components such as the polyester resin, the brominated epoxy flame retardant, and the glycidyl group-containing vinyl-based polymer, and melt kneading the thy blended components using any of various typical kneading machines. Examples of kneading machines include a single-screw extruder, a twin-screw extruder, a roll, a Banbuiy mixer, and a kneader. In particular, a twin-screw extruder 10 is preferred in terms of the adjustment of the degree of kneading and the ease of operation. The melt kneading is not particularly limited but is preferably carried out at a temperature equal to or higher than the melting point of the polyester resin, for example, at a temperature of 250 to 280 C. It is preferable that the polyester-based fiber for artificial hair is produced by 15 melt kneading the above-described polyester resin composition containing the polyester resin, the brominated epoxy flame retardant, the glycidyl group-containing vinyl-based polymer, and the like, and melt spinning the melt kneaded polyester resin composition. To produce the polyester-based fiber for artificial hair of the present invention, the polyester resin composition containing the polyester resin and the 20 brominated epoxy flame retardant is subjected to melt spinning such that the polyester resin (after made into fiber) has a larger melt viscosity than that of the brominated epoxy flame retardant (after made into fiber) at 280 C, and the fiber has a viscosity of 2,000 to 8,000 poise at a shear rate of 50 mmlinin when melted at 280 C. Consequently, it is possible to obtain the polyester-based fiber for artificial hair in 25 which the brominated epoxy flame retardant dispersed in the polyester resin has an average diagonal width of 0.05 pm or less in the cross section of the fiber parallel to the fiber axis direction. In terms of spinning stability, the fiber has a viscosity of preferably 2,000 to 8,000 poise at a shear rate of 50 mm/min when melted at 280 C. When the viscosity 30 is 2,000 poise or more, unevenness in fineness can be reduced. Further, when the viscosity is 8,000 poise or less, resin pressure does not become too high, so that the productivity can be improved with ease. 11

13 The polyester-based fiber for artificial hair of the present invention may be produced by conventional melt spinning, e.g., the melt kneaded polyester resin composition is melt spun into yarns while the temperatures of an extruder, a gear pump, a spinneret, etc. are set to 250 to 310 C. Then, the obtained yarns are cooled to 5 a temperature of not more than the glass transition point of the polyester resin, and wound up at a speed of 50 to 5000 m/min, and thus spun yarns (undrawn yarns) are obtained. Moreover, the spun yarns may be cooled in a water bath containing cooling water so as to control the fineness. The temperature and amount of the cooling air applied, the temperature of the cooling water bath, the cooling time, and the winding 10 speed can be adjusted appropriately in accordance with the extrusion rate of the polymer and the number of holes of the spinneret. In the present invention, it is preferable that the resultant spun yarns (undrawn yarns) are hot drawn. The drawing may be performed by either a two-step method or a direct drawing method. In the two-step method, the spun yarns are once 15 wound, and then drawn. In the direct drawing method, the spun yarns are drawn continuously without winding. The hot drawing may be performed by a single-stage drawing method or a multi-stage drawing method that includes two or more stages. The heating means for the hot drawing may be, e.g., a heating roller, a heat plate, a steam jet apparatus, or a hot water bath, and they can be used in combination as 20 desired. It is preferable that the polyester-based fiber for artificial hair of the present invention is a fiber like non-crimped raw silk. Further, from the viewpoint of being suitable for artificial hair, the fineness of the fiber is preferably 10 to 100 dtex. The lower limit of the fineness of the polyester-based fiber for artificial hair is more 25 preferably 20 dtex or more, and even more preferably 35 dtex or more. The upper limit of the fineness of the polyester-based fiber for artificial hair is more preferably 90 dtex or less, and even more preferably 80 dtex or less. The polyester-based fiber for artificial hair of the present invention has excellent flame retardance and color development and less fiber fusion. 30 The flame retardance of the polyester-based fiber for artificial hair can be determined based on the LOT value and whether or not dripping occurs in a combustion test. Ways to measure the LOT value and conduct the combustion test 12

14 will be described later. In terms of achieving excellent flame retardance, it is preferable that the polyester-based fiber for artificial hair has an LOI value of 23 or more, and dripping does not occur in the combustion test. It is more preferable that the polyester-based fiber for artificial hair has an LOT value of 25 or more, and 5 dripping does not occur in the combustion test. The polyester-based fiber for artificial hair of the present invention (multifilament) has less fiber fusion. For example, when evaluating fiber fusion (described later), the number of fused fibers is preferably less than 50, and more preferably less than The polyester-based fiber for artificial hair of the present invention alone can be used as artificial hair as is. Alternatively, the polyester-based fiber for artificial hair can be mixed with at least one fiber selected from the group consisting of human hair, animal hair, a polyvinyl chloride-based fiber, a modacrylic fiber, a polyamide-based fiber, a polyolefin-based fiber, a regenerated protein fiber, and other 15 polyester-based fiber to form a fiber bundle for hair. The fiber bundle for hair has excellent flame retardance and color development and less fiber fusion. A hair ornament product produced using the polyester-based fiber for artificial hair of the present invention has excellent flame retardance and color development. Further, the hair ornament product has less fiber fusion. Examples of the hair 20 ornament product include, but are not particularly limited to, hair wigs, hairpieces, weavings, hair extensions, blade hair, hair accessories, and doll hair. The hair ornament product may only include the polyester-based fiber for artificial hair of the present invention. Further, to form the hair ornament product, the polyester-based fiber for artificial hair of the present invention may be combined 25 with at least one fiber selected from the group consisting of htunan hair, animal hair, a polyvinyl chloride-based fiber, a modacrylic fiber, a polyamide-based fiber, a polyolefin-based fiber, a regenerated protein fiber, and other polyester-based fiber. Examples 30 Hereinafter, the present invention will be described in more detail based on Examples. It should be noted that the present invention is not limited to the following Examples. 13

15 The following compounds were used in Examples and Comparative Examples. Polyethylene terephthalate (hereinafter also referred to as "PET): trade name "RT543" manufactured by Japan Unipet Co., Ltd., IV=0.75 Brominated epoxy flame retardant 1 (hereinafter also referred to as "flame 5 retardant 1"): trade name "SRT.20000" manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., number average molecular weight: 40,000, epoxy-terminated type brominated epoxy flame retardant Brominated epoxy flame retardant 2 (hereinafter also referred to as "flame retardant 2"): trade name "F2400" manufactured by ICL industrial products, number 10 average molecular weight: 55,000, epoxy-terminated type brominated epoxy flame retardant Flame retardant auxiliary 1: sodium antimonate (trade name "SAA" manufactured by Nihon Seiko Co., Ltd.) Flame retardant auxiliary 2: antimony trioxide (trade name "PATOXM" 15 manufactured by Nihon Seiko Co., Ltd.) Thickener 1: glycidyl group-containing vinyl-based polymer (trade name "MARPROOF G-01100", manufactured by NOF Corporation, GMA: 100 wt%) Thickener 2: glycidyl group-containing vinyl-based polymer (trade name "ADR4300S", manufactured by BASF Corporation, GMA: 5 wt%) 20 Bromide absorbent: hydrotalcite (trade name "HT-1" manufactured by Kyowa Chemical Industry Co., Ltd.) Examples 1 to 4, Comparative Examples 1 to 3 The above PET (raw material) was dried to a moisture content of 100 ppm or 25 less, and then was dry blended with other raw materials in the proportions as shown in Table 1 below. The polyester resin composition thus obtained was supplied to a twin-screw extruder and melt kneaded at 280 C, and then was formed into pellets. The pellets were dried to a moisture content of 100 ppm or less. Next, the dried pellets were supplied to a melt spinning machine, and a molten polymer was extruded 30 at 280 C through a spinneret with nozzle holes having a circular cross section and a diameter of 0.5 mm. The extruded polymer was cooled to a temperature of not more than the glass transition point of the polyester resin, and wound up at a speed of 60 to 14

16 150 m/min, thereby providing undrawn yarns. The resultant undrawn yarns were drawn to 3 times at 80 C, heat-treated using the heating roller at 200 C. Thus, a polyester-based fiber (multifilament) with a single fiber fineness of about 60 dtex was produced. 5 With regard to each of the polyester-based fibers obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the melt viscosity of the polyester resin (PET) at 280 C (PET melt viscosity) and the melt viscosity of the brominated epoxy flame retardant at 280 C (flame retardant melt viscosity) were measured in the following manner, and Table 1 provides the results. Further, with regard to each of the 10 polyester-based fibers obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the viscosity of each polyester-based fiber at a shearing rate of 50 mm/min when melted at 280 C (fiber viscosity) was measured, and Table 1 provides the results. Further, with regard to each of the polyester-based fibers obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the average diagonal width of the brominated 15 epoxy flame retardant dispersed in the polyester resin in the cross section of the fiber parallel to the fiber axis direction (average diagonal width of flame retardant) was measured in the following manner, and Table 1 provides the results. Further, with regard to each of the polyester-based fibers obtained in Examples 1 to 4 and Comparative Examples 1 to 3, their flame retardance, color development, and fiber 20 fusion were measured/evaluated in the following manner, and Table 1 provides the results. Fiber Viscosity First, an extrusion load (F) was measured using a Capillograph 25 (manufactured by ribyo Seiki Seisaku-Sho Co., Ltd.) under the following conditions (test speed: 50 mm/min, orifice: 0.05 cm, barrel radius: cm, barrel temperature: 280 C). Then, the melt viscosity was calculated using the following formulas, and used as the fiber viscosity Shear pressure rt = P r / 2L = F. r / 2nR2L (1) 30 Flow value Q = nry (2) Shear rate y = 4Q/ n r3 = 4V / 60 n r3 (3) Apparent viscosity (melt viscosity) 11 = t / y (4) 15

17 In the formulas (1) to (4), is the shear pressure, P is the internal pressure of the barrel, F is the extrusion load, R is the radius of the barrel, r is the capillaiy radius, L is the capillary length, Q is the flow value, v is the extrusion rate, y is the shear rate, V is the amount of extrusion, and ri is the apparent viscosity (melt viscosity). 5 Melt Viscosity of Polyester Resin in Fiber 'lb measure the viscosity of the polyester resin in each fiber, the fiber was dissolved in a mixed solvent of hexafluoroisopropanol and chloroform (hexafluoroisopropanolkhloroform = 1/1) and was made into a film. The film thus 10 obtained was dissolved in hexafluoroisopropanol, and components dissolved in hexafluoroisopropanol were precipitated using methanol. The precipitate thus obtained (polyester resin component) was cracked, thus obtaining a sample. By using the sample thus obtained, the melt viscosity of the polyester resin in the fiber was measured/calculated in the same manner as measuring the fiber viscosity 15 Melt Viscosity of Brominated Epoxy Flame Retardant in Fiber To measure the viscosity of the brominated epoxy flame retardant in each fiber, the fiber was dissolved in a mixed solvent of hexafluoroisopropanol and chloroform (hexafluoroisopropanol/chloroform = 1/1) and was made into a film. The film thus 20 obtained was dissolved in chloroform, and components dissolved in chloroform were precipitated using methanol. The precipitate thus obtained (brominated epoxy flame retardant component) was cracked, thus obtaining a sample. By using the sample thus obtained, the melt viscosity of the flame retardant in the fiber was measured/calculated in the same manner as measuring the fiber viscosity 25 Average Diagonal Width of Brominated Epoxy Flame Retardant The diagonal width of the brominated epoxy flame retardant in the cross section of the fiber parallel to the fiber axis direction was observed and measured in the following analysis method. The preparation (ion milling) of the cross section of 30 the fiber parallel to the fiber axis direction was performed using a cross section polisher (CP) (SM CI?" manufactured by JEOL Ltd.) under the processing conditions of an acceleration voltage of 6 kv. The morphological observation of the of- 16

18 cross section of the fiber parallel to the fiber axis direction was carried out with a field emission scanning electron microscope (FE-SEM) ("ULTRA plus" manufactured by Carl Zeiss Co., Ltd.) at an acceleration voltage of 2 kv. Since a composition image of a sample depends on the average atomic number, the image becomes bright in a portion 5 of the sample that includes heavy elements and becomes dark in a portion of the sample that includes light elements. Samples (polyester-based fibers) each included the polyethylene terephthalate, the brominated epoxy flame retardant, and the antimony compound. Therefore, the order in which the bright composition image appeared was (1) antimony compound, (2) brominated epoxy flame retardant, and (3) 10 polyethylene terephthalate. Using the image analysis software ("winroof' available from Mitani Corporation), the diagonal width and the number of the brominated epoxy flame retardant per 360 inn 2 were measured from the image obtained to calculate the average diagonal width of the brominated epoxy flame retardant per 360 lim 2, and the average diagonal width obtained was used as the 15 average diagonal width of the brominated epoxy flame retardant. Flame Retardance Flame retardance was determined by the following four criteria based on an LOT value and whether or not dripping occurred in the combustion test. 20 A: Dripping does not occur and the LOT value is 25 or more. B:Dripping does not occur and the LOT value is 23 or more and less than 25. C:Dripping occurs and the LOI value is 23 or more. D:Regardless of whether or not dripping occurs, the LOI value is less than 23. <Meastuement of LOT Value> 25 The LOT value was measured in conformity with JIS L 1091 E (oxygen index test). More specifically, both ends of a filaments (length: 16 cm, weight: 0.25 g) were brought together slightly with double stick tape, and the filaments were twisted using a twisting device. After twisting the filaments sufficiently, the filaments were folded at the center and were twisted again. Then, both ends of the twisted filaments were 30 fixed to each other with Cellophane tape such that the twist filaments had a total length of 7 cm, thus obtaining a sample. The sample thus obtained was pre-dried for 60 minutes at 105 C, and was further dried in a desiccator for 30 minutes or more. 17

19 The dried sample was adjusted to a certain oxygen concentration. 40 seconds later, the sample was lit from the top with an igniter with the igniter flame restricted to 8 to 12 mm, and after lighting the sample, the igniter was removed. The oxygen concentration at which 5 cm or more of the sample was burned or the sample was 5 burned for 3 minutes or more was checked. The test was repeated 3 times under the same conditions, thereby obtaining the limit oxygen index (LOT). <Combustion Thst> 0.7 g worth of filaments, which were cut into a length of 150 mm, were tied into a bundle, and one end of the bundle was clamped and fixed to a stand so that the 10 bundle had an effective length of 120 mm, and the bundle was suspended vertically from the stand. A 20 mm flame was applied to the fixed filament bundle for 3 seconds to burn the filament bundle, and whether or not dripping occurred was observed. Color Development 15 Tow filaments having a length of 30 cm and total fineness of 100,000 dtex were compared with the appearance of human hair by visual observation under sun light, and were evaluated by the following four criteria. A:The hue of the fiber is clear and similar to that of human hair. B:The fiber is somewhat cloudy, and its color is slightly less clear in 20 comparison with the external appearance of human hair. 25 C:The fiber is cloudy, and its color is less clear in comparison with the external appearance of human hair. D:The fiber is strongly cloudy, and its color is distinctly less clear in comparison with the external appearance of human hair. Fiber Fusion Twenty fiber bundles (length: 50 cm, weight: 136 g) were combed at least 30 times by running a comb made of a polyacetal resin (trade name "NEW DELRIN COMB No. 826" manufactured by Uehara Cell) from a point 3 cm below the top of the 30 fiber bundles down through it at a speed of 0.3 m/s. Fiber fusion was determined as follows based on the number of fused fibers that were caught in the comb. A: The number of fused fibers is less than 10. ov-- 18

20 B:The number of fused fibers is 10 or more and less than 50. C:The number of fused fibers is 50 or more and less than 100. D: The number of fused fibers is 100 or more. 5 [TABLE 1] Ex. 1 Ex. 2 Ex. 3 Ex. 4 Comp. Ex. 1 Comp. Ex. 2 Comp. Ex. 3 PET (parts by weight) Flame retardant 1 (parts by weight) Flame retardant 2 (parts by weight) Flame retardant auxiliary 1 (parts by weight) Flame retardant auxiliary 2 (parts by weight) 2 Thickener 1 (parts by weight) 0.5 Thickener 2 (parts by weight) Bromide absorbent 0.6 PET melt viscosity (poise) Flame retardant melt viscosity (poise) Fiber viscosity (poise) Average diagonal width of flame retardant LOI value Dripping Does not occur Does not occur Does not occur Does not occur Does not occur Does not occur Occurs Flame retardance A A A A A A D Color development A A A A D D A Number of fused fibers Fiber fusion B B A C B A A As is clear from the results provided in Table 1, with regard to each of the polyester-based fibers of Examples 1 to 4, the brominated epoxy flame retardant dispersed in the polyester resin had an average diagonal width of 0.05 pm or less in 10 the cross section of the fiber parallel to the fiber axis direction, the polyester resin had a larger melt viscosity than that of the brominated epoxy flame retardant at 280 C, and each fiber had a viscosity within a range of 2,000 to 8,000 poise at a shear rate of 50 mm/min when melted at 280 C. On the other hand, with regard to each of the polyester-based fibers of Comparative Examples 1 to 2, the bmminated epoxy flame vv-- 19

21 retardant dispersed in the polyester resin had an average diagonal width of more than 0.05 pm in the cross section of the fiber parallel to the fiber axis direction, and the polyester resin had a smaller melt viscosity than that of the brominated epoxy flame retardant at 280 C. 5 The polyester-based fibers of Examples 1 to 4, in each of which the brominated epoxy flame retardant had an average diagonal width of 0.05 pm or less in the cross section of the fiber parallel to the fiber axis direction, had excellent flame retardance and favorable color development. Further, almost no fiber fusion was seen in the polyester-based fiber of Example 3 containing hydrotalaite. As can be seen from the 10 comparison between Examples 2 and 4, fiber fusion was reduced when the glycidyl group-containing vinyl-based polymer containing 1 to 20 wt% glycidyl methacrylate with respect to the total weight of the polymer was used. On the other hand, the polyester-based fibers of Comparative Examples 1 to 2, in each of which the brominated epoxy flame retardant dispersed in the polyester resin 15 had an average diagonal width of more than 0.05 pm in the cross section of the fiber parallel to the fiber axis direction, had poor color development. Further, the polyester-based fiber of Comparative Example 3 that contained no brominated epoxy flame retardant had poor flame retardance. The invention may be embodied in other forms without departing from the 20 spirit or essential characteristics thereof The embodiments disclosed in this 25 application are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein. 07 Fry EICEME LY YA 0 20

22 WHAT IS CLAIMED IS: 1. A polyesterbased fiber for artificial hair, comprising a polyester resin and a brominated epoxy flame retardant, wherein the polyester resin is at least one resin selected from the group 5 consisting of polyalkylene terephthalate and a copolymerized polyester containing polyalkylene terephthalate as a main component, and the brominated epoxy flame retardant dispersed in the polyester resin has an 10 average diagonal width of 0.05 Jim or less in a cross section of the fiber parallel to the fiber axis direction. 2. The polyester-based fiber for artificial hair according to claim 1, wherein the polyester resin has a larger melt viscosity than that of the brominated epoxy flame retardant at 280 C The polyester-based fiber for artificial hair according to claim 1 or 2, wherein when melted at 280 C, the fiber has a viscosity of 2,000 to 8,000 poise at a shear rate of 50 mm/min. 4. The polyesterbased fiber for artificial hair according to any one of claims 1 to 20 3, further comprising 0.6 to 5 parts by weight of a glycidyl group-containing vinyl-based polymer with respect to 100 parts by weight of the polyester resin. 5. The polyesterbased fiber for artificial hair according to claim 4, wherein the glycidyl group-containing vinyl-based polymer comprises 1 to 20 wt% of g,lycidyl 25 methacrylate with respect to the total weight of the glycidyl group-containing vinyl-based polymer. 6. The polyester-based fiber for artificial hair according to any one of claims 1 to 5, further comprising 0.2 to 3 parts by weight of hydrotalcite with respect to 100 parts 30 by weight of the polyester resin. 7. A fiber bundle for hair, comprising: w- 21

23 the polyesterbased fiber for artificial hair according to any one of claims 1 to 6; and at least one fiber selected from the group consisting of human hair, animal hair, a polyvinyl chloride-based fiber, a modacrylic fiber, a polyamide-based fiber, a 6 polyolefin-based fiber, a regenerated protein fiber, and another polyester-based fiben 8. A hair ornament product comprising the polyester-based fiber for artificial hair according to any one of claims 1 to The hair ornament product according to claim 8, further comprising at least one fiber selected from the group consisting of human hair, animal hair, a polyvinyl chloride-based fiber, a modacrylic fiber, a polyamide-based fiber, a polyolefin-based fiber, a regenerated protein fiber, and another polyester-based fiber. EKE4L4 ENIAPI/11 'Sari 3.P. 6 YA01 Tel. 22

24 FIG. 1 Eigm7 F E v 2014' LY

25 Planche de l'abrege FIG. 1

26