Flame-retardant resin composition and coated copper wire

[Technical field to which the invention belongs] The present invention<u style="single">, Covered</u>For more details on covered electric wires, automobile parts, electrical / electronic equipment parts, etc.<u style="single">Suitable for wiring</u>Used for<u style="single">, Difficult</u>Flammable resin composition<u style="single">Things</u>It relates to a covered electric wire coated on a conductor.

[0002] Conventional Technology [Conventional] As a coating material for a coated electric wire used for wiring of automobile parts, electric / electronic equipment parts, etc., a polyvinyl chloride resin having excellent flame retardancy is generally used. Blending agents such as plasticizers and stabilizers are appropriately blended with this according to mechanical properties such as wear resistance and tensile strength, and various required properties such as flexibility and workability, and types of these blending agents. And the amount of compounding has been adjusted.

[0003] However, while polyvinyl chloride resin has flame retardancy by itself, it has a halogen element in the molecular chain, so that it is used during combustion such as in the event of an automobile fire or incineration of electrical and electronic equipment. It has the problem of releasing harmful halogen-based gases into the atmosphere and causing environmental pollution.

[0004] Against this background, various flame-retardant resin compositions containing no halogen component have been studied in recent years. For example, Japanese Patent Application Laid-Open No. 5-301996 describes a mixture of polyolefin and high-density polyethylene. Discloses a non-halogen flame-retardant resin composition containing a metal hydrate as a flame retardant.

[0005] For example, Japanese Patent Application Laid-Open No. 7-10912 discloses a non-halogen flame-retardant resin composition in which an inorganic flame retardant is mixed with a mixture of a thermoplastic elastomer and a low-crystalline polyolefin.

[0006] Further, for example, Japanese Patent Application Laid-Open No. 7-78518 describes a resin composition obtained by blending surface-treated magnesium hydroxide with a mixture of a polyolefin having a melting point of 120 ° C. or higher and a carboxylic acid-modified polymer. Covered and crosslinked coated wires are disclosed.

[0007] [Problems to be Solved by the Invention] However, in the case of the non-halogen flame retardant resin composition shown in JP-A-5-301996, it is difficult to make the composition flame retardant enough to have self-extinguishing property. It is necessary to add a large amount of metal hydrate as a flame retardant, and such a composition has a problem that mechanical properties such as wear resistance and tensile strength are remarkably lowered.

[0008] On the other hand, in order to improve the mechanical properties, it is possible to increase the mixing amount of high-density polyethylene having crystallinity and relatively high hardness, but the amorphous portion is reduced and a small amount of flame retardant is used. A resin composition with excellent properties, such as being able to be blended only, reducing flame retardancy and impairing flexibility, and extremely poor processability and extrusion moldability when used as a coating material for coated electric wires. There is a problem that it cannot be obtained.

[0009] Further, also in the case of the non-halogen flame-retardant resin composition shown in Japanese Patent Publication No. 7-10912, it is necessary to add a large amount of an inorganic flame retardant in order to make the composition flame-retardant enough to have self-extinguishing property. Similar to the former, there is a problem that mechanical properties such as wear resistance and tensile strength are remarkably lowered, and further, the flexibility of the thermoplastic elastomer is impaired. On the other hand, if the mixing amount of the low crystallinity polyolefin is reduced in order to improve the mechanical properties, the amorphous portion is reduced and only a small amount of the inorganic flame retardant can be blended, which causes a problem that the flame retardancy is lowered. , There is a problem that a resin composition having excellent characteristics cannot be obtained.

[0010] Further, in the case of the coated electric wire shown in Japanese Patent Application Laid-Open No. 7-78518, since it is necessary to carry out cross-linking, there are problems such as introduction of cross-linking equipment in production of the coated electric wire, increase in manufacturing process, cost increase and the like. Occurs.

[0011] As described above, the flame-retardant resin composition as described above.<u style="single">Was used</u>The covered electric wire has a problem that excellent electric wire characteristics cannot be obtained.

[0012] Therefore, the problem to be solved by the present invention is that it does not generate halogen-based gas during combustion, has sufficient flame retardancy, and has mechanical properties such as wear resistance, tensile strength, and tensile elongation. Flame-retardant resin composition having flexibility and workability<u style="single">Covered</u>The purpose of the present invention is to provide a covered electric wire used as a covering material.<u style="single">【0013】</u>[Means for solving problems]<u style="single">To solve this problem</u>The gist of the coated electric wire according to the present invention is that the outermost circumference of the conductor is coated with a specific flame-retardant resin composition.<u style="single">【0014】</u> Here, the flame-retardant resin composition is mixed at a mixing ratio of 60 to 97 parts by weight of the propylene-based resin and 3 to 40 parts by weight of the modified styrene-based thermoplastic elastomer modified with unsaturated carboxylic acid or a derivative thereof. A mixture of 30 to 200 parts by weight of metal hydrate is used with respect to 100 parts by weight of the total mixture.<u style="single">【0015】</u> Since this flame-retardant resin composition does not contain a halogen element, it does not generate a harmful halogen-based gas during combustion. Further, since 60 to 97 parts by weight of a propylene resin having a relatively high melting point is mixed among the olefin resins, the heat resistance can be improved without cross-linking.<u style="single">【0016】</u> In addition, since 3 to 40 parts by weight of a modified styrene-based thermoplastic elastomer modified with unsaturated carboxylic acid or a derivative thereof is mixed, it is excellent in flexibility and modified with metal hydrate which is a highly polar flame retardant. A strong bonding interface is formed between the modified portion of the styrene-based thermoplastic elastomer, and it is possible to improve mechanical properties such as abrasion resistance, tensile strength, and tensile elongation without impairing flexibility.<u style="single">【0017】</u> Further, since it has an excellent balance of mechanical properties and flexibility, it is excellent in workability and moldability. In addition, since it contains 30 to 200 parts by weight of metal hydrate, it has sufficient flame retardancy.<u style="single">【0018】</u> At this time, it is preferable that the modified styrene-based thermoplastic elastomer modified with an unsaturated carboxylic acid or a derivative thereof is a maleic anhydride-modified styrene-based thermoplastic elastomer, and the metal hydrate is magnesium hydroxide. In this case, it is possible to further improve mechanical properties such as wear resistance.<u style="single">【0019】</u> Further, the thickness of the coating material of the coated electric wire is preferably in the range of 0.2 to 0.3 mm.<u style="single">【0020】</u>BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the invention will be described in detail. The flame-retardant resin composition in the present application is a mixture obtained by mixing 60 to 97 parts by weight of a propylene-based resin and 3 to 40 parts by weight of a modified styrene-based thermoplastic elastomer modified with an unsaturated carboxylic acid or a derivative thereof. It consists of a mixture of 30 to 200 parts by weight of metal hydrate with respect to 100 parts by weight in total.<u style="single">【0021】</u> Here, the propylene-based resin refers to a polymer of propylene or a polymer mainly composed of propylene, which does not contain a halogen element in its molecular structure. The structure of these polymers may be a homopolymer, a random polymer, an alternate polymer, or a block polymer, and is not particularly limited.<u style="single">【0022】</u> Specifically, polypropylene, a propylene-ethylene block copolymer containing propylene as a main component (50 wt% or more), a propylene-ethylene random copolymer, a propylene-butene random copolymer, and a propylene / ethylene-propylene block copolymer. Examples include coalescence. It should be noted that these may be used alone or in combination of two or more, and are not particularly limited.<u style="single">【0023】</u> The propylene resin is a melt flow rate measured in accordance with JIS K 6758 (measured at a temperature of 230 ° C and a weight of 2.16 kg) from the viewpoint of improving workability, extrusion moldability, etc. MFR ") is preferably in the range of 0.1g to 5g / 10 minutes.<u style="single">【0024】</u> Here, the styrene-based thermoplastic elastomer in the modified styrene-based thermoplastic elastomer modified with an unsaturated carboxylic acid or a derivative thereof is the copolymerization of the styrene-based resin as a hard segment and the rubber-based resin as a soft segment. A coalescence that does not contain halogen elements in its molecular structure.<u style="single">【0025】</u> Since the thermoplastic elastomer has a hard segment corresponding to a cross-linking point and a soft segment exhibiting rubber-like elasticity near room temperature in its molecular structure, it is softened by heating and plastically deformed by an external force. It has the property of exhibiting rubber-like elasticity near room temperature.<u style="single">【0026】</u> Specifically, as hard segments, polystyrene, polyo-methylstyrene, polym-methylstyrene, polyp-methylstyrene, polyα-methylstyrene, polyβ-methylstyrene, polydimethylstyrene, polytrimethylstyrene and the like can be used. Examples of the soft segment include polybutadiene, ethylene-propylene copolymer, ethylene-propylene-diene ternary copolymer, polyisoprene, butadiene-isoprene copolymer and the like. The styrene-based thermoplastic elastomer composed of these may be used alone or in combination of two or more, and is not particularly limited.<u style="single">【0027】</u> As such a styrene-based thermoplastic elastomer, a styrene-butadiene copolymer and a styrene / ethylene-propylene copolymer are suitable. The structure of the styrene-based thermoplastic elastomer is not particularly limited, such as a random copolymer, an alternating copolymer, and a block copolymer, but a block copolymer is preferable. More specifically, styrene-butadiene block copolymers and styrene / ethylene-propylene block copolymers are particularly suitable.<u style="single">【0028】</u> Further, the styrene-based thermoplastic elastomer is preferably a hydrogenated styrene-based thermoplastic elastomer in which the double bonds in the molecular chain are saturated by hydrogenation from the viewpoint of improving heat resistance. More specifically, hydrogenated styrene-butadiene block copolymers and hydrogenated styrene / ethylene-propylene block copolymers are the most suitable.<u style="single">【0029】</u> The modified styrene-based thermoplastic elastomer modified with the unsaturated carboxylic acid or its derivative is obtained by reacting the unsaturated carboxylic acid or its derivative with the styrene-based thermoplastic elastomer described above to copolymerize or graft-modify it. Say something.<u style="single">【0030】</u> Examples of the unsaturated carboxylic acid used for modification include maleic acid, fumaric acid, itaconic acid, and acrylic acid, and examples of the derivative of the unsaturated carboxylic acid include maleic anhydride, maleic acid monoester, maleic acid diester, and anhydrous. Examples thereof include fumaric acid, fumaric acid monoester, fumaric acid diester, itaconic anhydride, itaconic acid monoester, and itaconic acid diester. Among them, maleic anhydride is most preferable from the viewpoint of further improving mechanical properties such as wear resistance.<u style="single">【0031】</u> At this time, the modification ratio of the modified styrene-based thermoplastic elastomer is preferably in the range of 0.1 to 10% by weight. If it is less than 0.1% by weight, the chemical bonding force on the surface of the metal hydrate decreases, a strong bonding interface cannot be obtained, and the effect of denaturation tends to be reduced, which is not preferable. It is not preferable because the balance of various characteristics tends to be poor.<u style="single">【0032】</u> The metal hydrate compounded as a flame retardant does not contain a halogen element, and specific examples thereof include magnesium hydroxide, aluminum hydroxide, and calcium hydroxide. Of these, magnesium hydroxide is preferable because the decomposition temperature is as high as around 360 ° C. The average particle size of these metal hydrates is preferably 0.1 to 20 μm from the viewpoint of further improving mechanical properties such as wear resistance.<u style="single">【0033】</u> At this time, from the viewpoint of enhancing dispersibility in the polymer and reactivity with the polymer, the particle surface of the metal hydrate is a silane coupling agent such as aminosilane, vinylsilane, epoxysilane, and methacryloxysilane, or stearic acid and oleic acid. The surface may be treated with a higher fatty acid such as an acid.<u style="single">【0034】</u> In the flame-retardant resin composition of the present application, the propylene-based resin described above is mixed in the range of 60 to 97 parts by weight, and the modified styrene-based thermoplastic elastomer modified with unsaturated carboxylic acid or a derivative thereof is mixed in the range of 3 to 40 parts by weight. It is preferable that 30 to 200 parts by weight of the metal hydrate is blended with respect to 100 parts by weight of the total of these mixtures. Each of these components can be adjusted by mixing and kneading by a usual method, and the adjusting method is not particularly limited.<u style="single">【0035】</u> If the amount of the propylene resin is less than 60 parts by weight, the abrasion resistance tends to decrease, and if it is more than 97 parts by weight, the flexibility and workability tend to be impaired, which is not preferable. Further, if the amount of the modified styrene-based thermoplastic elastomer is less than 3 parts by weight, flexibility and workability tend to be impaired, which is not preferable, and if it is more than 40 parts by weight, the wear resistance tends to be impaired, which is not preferable. ..<u style="single">【0036】</u> Further, if the amount of metal hydrate is less than 30 parts by weight, sufficient flame retardancy cannot be obtained, and if it is more than 200 parts by weight, tensile elongation is deteriorated and wear resistance, flexibility and workability are impaired. It is not preferable because it tends to occur.<u style="single">【0037】</u> Particularly preferably, a propylene-based resin is mixed in the range of 70 to 90 parts by weight, and a modified styrene-based thermoplastic elastomer modified with an unsaturated carboxylic acid or a derivative thereof is mixed in the range of 10 to 30 parts by weight, and a total of 100 parts thereof is mixed. It is preferable that 50 to 150 parts by weight of the metal hydrate is blended with respect to the part by weight.<u style="single">【0038】</u> In addition, antioxidants that do not contain halogen elements, metal deactivators (copper external inhibitors, etc.), processing aids (lubricants, waxes, etc.), colorants, flame retardants (zinc borate, silicon-based flame retardants, etc.) ) And the like may be appropriately blended within a range that does not deteriorate each characteristic, and is not particularly limited.<u style="single">【0039】</u> Next, the action of the flame-retardant resin composition will be described.<u style="single">【0040】</u> Since the flame-retardant resin composition does not contain a halogen element, it does not generate a harmful halogen-based gas during combustion. Therefore, when used as a coating material for coated electric wires used in automobile parts, electrical / electronic equipment parts, etc., halogen-based gas is not released into the atmosphere in the event of an automobile fire or incineration of electrical / electronic equipment. , Does not cause environmental pollution. Further, since 60 to 97 parts by weight of a propylene resin having a relatively high melting point is mixed among the olefin resins, the heat resistance can be improved in a non-crosslinked state without cross-linking.<u style="single">【0041】</u> In addition, since 3 to 40 parts by weight of a modified styrene-based thermoplastic elastomer modified with unsaturated carboxylic acid or a derivative thereof is mixed, it has excellent flexibility and is combined with metal hydrate which is a highly polar inorganic flame retardant. By forming a strong bonding interface with the modified portion of the modified styrene-based thermoplastic elastomer, it is possible to improve mechanical properties such as abrasion resistance, tensile strength, and tensile elongation without impairing flexibility. It will be possible. Further, since the propylene-based resin and the modified styrene-based thermoplastic elastomer have excellent compatibility, the resins can be well compatible with each other, and a uniform composition can be obtained without impairing various properties.<u style="single">【0042】</u> Further, the flame-retardant resin composition has an excellent balance of mechanical properties and flexibility, and has appropriate hardness and suppleness, so that it is excellent in workability and moldability.<u style="single">【0043】</u> In particular, the composition range of the flame-retardant resin composition is mixed in the range of 70 to 90 parts by weight of the propylene-based resin and 10 to 30 parts by weight of the modified styrene-based thermoplastic elastomer modified with unsaturated carboxylic acid or a derivative thereof. However, when 50 to 150 parts by weight of metal hydrate is blended with respect to 100 parts by weight of these mixtures in total, mechanical properties such as wear resistance, tensile strength, and tensile elongation are further improved. At the same time, a resin composition having an excellent balance of characteristics can be obtained.<u style="single">【0044】</u> Next, a coated electric wire obtained by coating the outermost periphery of the conductor with the flame-retardant resin composition described above as a coating material will be described. This coated electric wire is suitably used as a coated electric wire used for automobile parts, electric / electronic equipment parts, and the like.<u style="single">【0045】</u> The coated electric wire has a structure in which a flame-retardant resin composition is coated concentrically around the conductor on the outermost circumference of the conductor, and the conductor used is an annealed copper wire in accordance with JIS C 3102. It is preferable that a plurality of twisted wires or a plurality of annealed copper wires are twisted together and circularly compressed.<u style="single">【0046】</u> The coating thickness of the coated electric wire is preferably in the range of 0.2 mm to 0.3 mm. This is because when the coating thickness is thinner than 0.2 mm, the wear resistance of the coated wire tends to be impaired, and when the coating thickness is thicker than 0.3 mm, the flexibility of the coated wire tends to decrease.<u style="single">【0047】</u> If necessary, a plurality of layers of a halogen element-free resin composition or the like having other properties such as water resistance is coated between the flame-retardant resin composition coated as the coating material and the conductor. It may be, and is not particularly limited.<u style="single">【0048】</u> By the way, in order to obtain a coated electric wire having better electric wire characteristics, the composition range of the flame-retardant resin composition coated as a coating material is optimal according to the combination of the conductor cross-sectional area and the coating thickness. It is necessary to select the composition range.<u style="single">【0049】</u> Specifically, the conductor cross-sectional area is 0.35 mm²~ 1.5mm²When the coating thickness is 0.2 mm, the composition of the flame-retardant resin composition coated on the outer periphery of the conductor as a coating material is 90 parts by weight of the propylene resin and 10 parts by weight of the modified styrene thermoplastic elastomer, for a total of 100 parts by weight. On the other hand, the composition is preferably 70 parts by weight of the metal hydrate.<u style="single">【0050】</u> In addition, the conductor cross-sectional area is 0.22 mm²~ 1.5mm²When the coating thickness is 0.2 mm to 0.3 mm, the composition is 90 parts by weight of the metal hydrate with respect to 80 parts by weight of the propylene resin and 20 parts by weight of the modified styrene thermoplastic elastomer. Is preferable.<u style="single">【0051】</u> In addition, the conductor cross-sectional area is 1.5 mm²As mentioned above, when the coating thickness is 0.2 mm or more, 70 to 90 parts by weight of the metal hydrate is compared with 60 to 70 parts by weight of the propylene resin and 30 to 40 parts by weight of the modified styrene thermoplastic elastomer. The composition range is preferably.<u style="single">【0052】</u> At this time, particularly when the wire type (wire size) of the coated electric wire is thin, the composition of the flame-retardant resin composition coated on the outer periphery of the conductor as a coating material in order to obtain sufficient flame retardancy. The range is preferably a composition range of 100 to 200 parts by weight of the metal hydrate with respect to a total of 100 parts by weight of 65 to 97 parts by weight of the propylene resin and 3 to 35 parts by weight of the modified styrene thermoplastic elastomer.<u style="single">【0053】</u> More preferably, the composition range is 120 to 180 parts by weight of the metal hydrate with respect to 100 parts by weight in total of 70 to 95 parts by weight of the propylene resin and 5 to 30 parts by weight of the modified styrene thermoplastic elastomer. ..<u style="single">【0054】</u> Specifically, the conductor cross-sectional area is 0.13 mm²When the coating thickness is 0.2 mm, the composition is preferably 160 parts by weight of the metal hydrate with respect to 90 parts by weight of the propylene resin and 10 parts by weight of the modified styrene thermoplastic elastomer.<u style="single">【0055】</u> Next, the operation of the coated electric wire will be described.<u style="single">【0056】</u> Since the above-mentioned coated electric wire uses the above-mentioned flame-retardant resin composition as a coating material, it does not generate halogen-based gas during combustion, has sufficient flame retardancy, and has excellent mechanical properties, flexibility, and It also has workability. Further, since it is not necessary to carry out cross-linking, problems such as introduction of cross-linking equipment, increase in manufacturing process, and cost increase during production of coated electric wires do not occur.<u style="single">【0057】</u> Since this coated electric wire is excellent in workability, a whiskers-like covering material does not remain on the cutting end of the covering material when the coated electric wire terminal is peeled off. Therefore, when the conductor and the crimp terminal of the coated wire are crimped with the whiskers-like covering material remaining, the whiskers-shaped covering material is sandwiched between the conductor and the crimping terminal, and the resistance of the coated wire is high. It is possible to avoid the inconvenience of becoming a covered electric wire, and there is an effect that the workability at the time of peeling the covered electric wire terminal is also excellent.<u style="single">【0058】</u>[Examples] The present invention will be described in more detail below with reference to Examples.<u style="single">【0059】</u> Examples 1 to 5 include a propylene-ethylene block copolymer (density 0.90, temperature 230 ° C, MFR = 0.5 g / 10 minutes under a load of 2.16 kg, omitted below), styrene-butadiene modified with maleic anhydride. -Styrene copolymer (density 0.92, temperature 230 ° C, MFR = 5.0 g / 10 minutes under load 2.16 kg, omitted below), magnesium hydroxide A (average particle size 1.0 μm, silane coupling agent surface treatment) Each resin composition is kneaded with the treated product, magnesium hydroxide B (average particle size 1.0 μm, unsurfaced product, omitted below), and anti-aging agent at the ratios shown in Table 1. Was produced.<u style="single">【0060】</u> On the other hand, as Comparative Examples 1 to 5, propylene-ethylene block copolymer, maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer, and hydrogenated styrene-butadiene-styrene copolymer (density 0.91, temperature 230 ° C) , MFR = 5.0 g / 10 minutes under a load of 2.16 kg, omitted below), magnesium hydroxide A, magnesium hydroxide B, and an antiaging agent were kneaded at the ratios shown in Table 2 to prepare each resin composition. It should be noted that these are mainly compared in relation to Examples 1 to 5.<u style="single">【0061】</u> Then, in order to confirm the characteristics of each of these resin compositions in the state of electric wires, an extrusion molding machine was used to obtain a cross-sectional area of 0.5 mm.²(Seven annealed copper wires were twisted together and compressed into a circle to smooth the outer surface of this conductor) and extruded to a thickness of 0.28 mm to prepare each coated electric wire. The die nipples used for extrusion molding were 1.40 mmφ and 0.88 mmφ, respectively. The extrusion temperature was in the temperature range of 210 to 230 ° C for the die and 200 to 240 ° C for the cylinder, and the linear velocity was 50 m / min.<u style="single">【0062】</u> In Examples 6 to 10, propylene-ethylene block copolymer, maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer, magnesium hydroxide B, and antiaging agent were kneaded at the ratios shown in Table 3. Each resin composition was prepared. These resin compositions have a composition range that is suitably used as a coated electric wire having a thin wire type (wire size).<u style="single">【0063】</u> On the other hand, as Comparative Examples 6 to 10, propylene-ethylene block copolymer, maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer, hydrogenated styrene-butadiene-styrene copolymer, magnesium hydroxide B, anti-aging Each resin composition was prepared by kneading the agents at the ratios shown in Table 4. It should be noted that these are mainly compared in relation to Examples 6 to 10.<u style="single">【0064】</u> Then, in order to confirm the characteristics of each of these resin compositions in the state of electric wires, an extrusion molding machine was used to obtain a cross-sectional area of 0.13 mm.²(Seven annealed copper wires were twisted together and compressed into a circle to smooth the outer surface of this conductor) and extruded to a thickness of 0.20 mm to prepare each coated electric wire. The die nipples used for extrusion molding were 0.50 mmφ and 0.90 mmφ, respectively. The extrusion temperature was in the temperature range of 210 to 230 ° C for the die and 200 to 240 ° C for the cylinder, and the linear velocity was 50 m / min.<u style="single">【0065】</u> The manufacturing companies and trade names of the resins and compounding agents used in the above Examples and Comparative Examples are as follows. That is, the propylene-ethylene block copolymer is Tokuyama's "Tokuyama Polypro RB610A" (trade name), and the maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer is Asahi Kasei Kogyo's "Tough Tech M1913" (trade name). , Hydrogenated styrene-butadiene-styrene copolymer is "Tuftec H1041" (trade name) manufactured by Asahi Kasei Kogyo Co., Ltd., Magnesium hydroxides A and B are manufactured by Kyowa Kagaku Kogyo Co., Ltd. "(Product name).<u style="single">【0066】</u> Each of the coated electric wires manufactured as described above is subjected to a flame retardancy test, an abrasion resistance test, a tensile strength test, a tensile elongation test, a flexibility test and a workability test to evaluate the characteristics of the product of the present invention and the comparative product. went. Each test and evaluation method will be described below.<u style="single">【0067】</u> (Flame retardancy) The flame retardancy was tested in accordance with the Japanese Automotive Standards Organization "JASO D611-94". That is, each covered electric wire of the product of the present invention and the comparative product was cut out to a length of 300 mm and used as a test piece. Next, place each test piece in an iron test box and support it horizontally, and use a Bunsen burner with a diameter of 10 mm to apply the tip of the reducing flame from the lower side of the center of the test piece until it burns within 30 seconds. The afterglow time was measured after gently removing the shavings. At this time, those with a residual flame time of 15 seconds or less were rejected, and those with a residual flame time of more than 15 seconds were rejected.<u style="single">【0068】</u> (Abrasion resistance) The wear resistance test was conducted by the blade reciprocating method in accordance with the Japanese Automotive Standards Organization "JASO D611-94". That is, each covered electric wire of the product of the present invention and the comparative product was cut out to a length of 750 mm and used as a test piece. Then, at room temperature of 23 ± 5 ° C, the surface of the coating material of each test piece fixed on the table is reciprocated and worn over a length of 10 mm or more in the axial direction, and the blade is worn at 50 per minute. The number of reciprocations until the blade came into contact with the conductor was measured due to the wear of the covering material when the reciprocating material was reciprocated at the speed of reciprocation. At this time, the load applied to the blade was set to 7N.<u style="single">【0069】</u> Then, each test piece was moved 100 mm, rotated 90 degrees clockwise, and the above measurement was repeated. This measurement was performed three times in total with the same test piece, and for Examples 1 to 5 and Comparative Examples 1 to 5, those having a minimum value of 150 times or more were accepted, and Examples 6 to 10 and Comparative Examples 6 to 10 were passed. Was accepted if the minimum value was 100 times or more.<u style="single">【0070】</u> (Tensile strength and tensile elongation) Tensile strength and tensile elongation were tested in accordance with the Japanese Automotive Standards Organization "JASO D611-94". That is, each covered electric wire of the product of the present invention and the comparative product was cut out to a length of 150 mm, a tubular test piece was obtained by removing the conductor, and marked lines were marked at intervals of 50 mm in the central portion thereof. Then, after attaching both ends of each test piece to the chuck of the testing machine at room temperature of 23 ± 5 ° C, pulling at a tensile speed of 200 mm / min, the load at the time of cutting each test piece and the length between the marked lines. Was measured. At this time, those with a tensile strength of 15.7 MPa or more and a tensile elongation of 125% or more were accepted.<u style="single">【0071】</u> (Flexibility) As for the flexibility, the one with good hand feel when each covered electric wire was bent by hand was accepted.<u style="single">【0072】</u> (Workability) The workability was tested as follows. That is, it was confirmed whether or not a whiskers were formed when the resin-coated portion of the terminal portion of each covered electric wire was peeled off, and those without whiskers were accepted.<u style="single">【0073】</u> Tables 1 to 4 summarize the manufacturing conditions and evaluation results for each of the coated electric wires of the product of the present invention and the comparative product as described above.<u style="single">【0074】</u>[table 1]<img file="JP3669920B2_D0001.tif" /><u style="single">【0075】</u>[Table 2]<img file="JP3669920B2_D0002.tif" /><u style="single">【0076】</u>[Table 3]<img file="JP3669920B2_D0003.tif" /><u style="single">【0077】</u>[Table 4]<img file="JP3669920B2_D0004.tif" /><u style="single">【0078】</u> The following can be seen from the evaluation results of the product of the present invention and the comparative product in Tables 1 and 2. Each of the coated electric wires of Examples 1 to 5 according to one embodiment of the present invention satisfies all of flame retardancy, wear resistance, tensile strength, tensile elongation, flexibility and workability, whereas they are compared. It can be seen that none of the coated wires of Examples 1 to 5 satisfy all the characteristics.<u style="single">【0079】</u> In particular, as shown in Examples 3 and 5 shown in Table 1, the composition range of the flame-retardant resin composition is 70 to 90 parts by weight of the propylene-based resin, and the modified styrene-based modified with an unsaturated carboxylic acid or a derivative thereof. Abrasion resistance and tension when the composition range is 50 to 150 parts by weight of metal hydrate with respect to 100 parts by weight of the mixture mixed at a mixing ratio of 10 to 30 parts by weight of the thermoplastic elastomer. It can be seen that mechanical properties such as strength and tensile elongation can be further improved, and a resin composition having an excellent balance of properties can be obtained.<u style="single">【0080】</u> However, as shown in Table 2, Comparative Example 1 is flexible because the mixing ratio of the propylene-ethylene block copolymer is large and the mixing ratio of the maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer is small. And it can be seen that the workability was impaired. Further, in Comparative Example 2, since the mixing ratio of the propylene-ethylene block copolymer is small and the mixing ratio of the maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer is large, the tensile elongation is poor and the abrasion resistance is poor. It turns out that it was damaged.<u style="single">【0081】</u> Further, in Comparative Example 3, since the blending ratio of magnesium hydroxide, which is a flame retardant, is small, sufficient flame retardancy cannot be exhibited, and in Comparative Example 4, the blending ratio of magnesium hydroxide is large, so that the tensile strength is increased. It can be seen that the elongation was insufficient and the wear resistance, flexibility and workability were impaired.<u style="single">【0082】</u> Further, in Comparative Example 5, an unmodified hydrogenated styrene-butadiene-styrene copolymer was mixed in place of the maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer, so that the metal hydrate and the hydrogenated styrene were mixed. It can be seen that a strong bond interface was not formed with the -butadiene-styrene copolymer, and the wear resistance was impaired.<u style="single">【0083】</u> Next, the following can be seen from the evaluation results of the product of the present invention and the comparative product in Tables 3 and 4. Each of the coated electric wires of Examples 6 to 10 according to one embodiment of the present invention satisfies all of flame retardancy, wear resistance, tensile strength, tensile elongation, flexibility and workability, whereas they are compared. It can be seen that none of the coated wires of Examples 6 to 10 satisfy all the characteristics.<u style="single">【0084】</u> That is, as shown in Table 4, Comparative Example 6 is flexible because the mixing ratio of the propylene-ethylene block copolymer is large and the mixing ratio of the maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer is small. It can be seen that the property and processability were impaired. Further, in Comparative Example 7, since the mixing ratio of the propylene-ethylene block copolymer was small and the mixing ratio of the maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer was large, the abrasion resistance was impaired. I understand.<u style="single">【0085】</u> Further, in Comparative Example 8, since an unmodified hydrogenated styrene-butadiene-styrene copolymer was mixed instead of the maleic anhydride-modified hydrogenated styrene-butadiene-styrene copolymer, metal hydrate and hydrogenated styrene- It can be seen that a strong bond interface was not formed with the butadiene-styrene copolymer, and the wear resistance was impaired.<u style="single">【0086】</u> Further, in Comparative Example 9, since the blending ratio of magnesium hydroxide, which is a flame retardant, is out of the composition range preferably used as a coated electric wire having a thin wire type (wire size), sufficient flame retardancy is exhibited. In Comparative Example 10, it can be seen that the flexibility and workability were impaired due to the large proportion of magnesium hydroxide.<u style="single">【0087】</u> Although the examples have been described above, the present invention is not limited to the above examples, and various modifications can be made without departing from the spirit of the present invention. For example, in this embodiment, an anti-aging agent was blended as a compounding agent, but in addition to this, an antioxidant containing no halogen element, a metal deactivator (anti-copper agent, etc.), and a processing aid (lubricant, wax) Etc.), colorants, flame retardants (zinc borate, silicon-based flame retardants, etc.) and other compounding agents may be appropriately compounded as long as the characteristics are not deteriorated, and are not particularly limited.<u style="single">【0088】</u>[Effect of the invention]<u style="single"> Book</u>The coated electric wire according to the present invention is a modified styrene-based thermoplastic elastomer modified with 60 to 97 parts by weight of a propylene-based resin and an unsaturated carboxylic acid or a derivative thereof as a specific flame-retardant resin composition to be coated on the outermost periphery of a conductor. A mixture of 30 to 200 parts by weight of metal hydrate is used with respect to a total of 100 parts by weight of the mixture mixed at a mixing ratio of 3 to 40 parts by weight.<u style="single">【0089】</u> Therefore, since the flame-retardant resin composition as the coating material does not contain a halogen element, no harmful halogen-based gas is generated during combustion. Further, since 60 to 97 parts by weight of a propylene resin having a relatively high melting point is mixed among the olefin resins, the heat resistance can be improved without cross-linking.<u style="single">【0090】</u> In addition, since 3 to 40 parts by weight of a modified styrene-based thermoplastic elastomer modified with unsaturated carboxylic acid or a derivative thereof is mixed, it is excellent in flexibility and modified with metal hydrate which is a highly polar flame retardant. A strong bonding interface is formed between the modified portion of the styrene-based thermoplastic elastomer, and it is possible to improve mechanical properties such as abrasion resistance, tensile strength, and tensile elongation without impairing flexibility.<u style="single">【0091】</u> Further, since it has an excellent balance of mechanical properties and flexibility, it is excellent in workability and moldability. In addition, since it contains 30 to 200 parts by weight of metal hydrate, it has sufficient flame retardancy.<u style="single">【0092】</u> At this time, if the modified styrene-based thermoplastic elastomer modified with an unsaturated carboxylic acid or a derivative thereof is a maleic anhydride-modified styrene-based thermoplastic elastomer and the metal hydrate is magnesium hydroxide, wear resistance It is possible to further improve mechanical properties such as properties.<u style="single">【0093】</u> As described above, the coated electric wire according to the present invention does not generate halogen-based gas during combustion, has sufficient flame retardancy, and has excellent mechanical properties, flexibility, and workability. Can be. Further, since it is not necessary to carry out cross-linking, problems such as introduction of cross-linking equipment, increase in manufacturing process, and cost increase during production of coated electric wires do not occur.<u style="single">【0094】</u> As described above, it is difficult to have sufficient flame retardancy without generating halogen-based gas during combustion, and also to have mechanical properties such as wear resistance, tensile strength, and tensile elongation, flexibility, and workability. Flammable resin composition<u style="single">Lead</u>By covering the outermost circumference of the body, a covered electric wire having excellent electric wire characteristics can be obtained.