JP2006152039A - Polyamide resin composition for wire-coating, and resin-coated electric wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin-coated electric wire coated with a polyamide resin composition having excellent appearance, flame retardancy, flexibility and flexing resistance suitable for electric wire coating use. <P>SOLUTION: The polyamide resin composition for electric wire coating is composed of (A) 90-99.9 pts.wt. of a polyamide resin having relative viscosity of 1.5-7.0 and a melt peak temperature of ≥160°C determined at a temperature rising rate of 20°C/min in nitrogen atmosphere by using a differential scanning calorimeter (DSC) and (B) 0.1-10 pts.wt. of a triazine compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to a polyamide resin composition and a resin-coated electric wire excellent in appearance, flame retardance, flexibility, flex resistance and heat resistance suitable for electric wire coating applications.

  Today, temperature requirements for insulating materials for electric wires or cables used in the engine room of automobiles and the like are increasing. Polyvinyl chloride (PVC), which is used in large quantities in automobile wiring, is excellent in chemical resistance, flame retardancy, insulation, and toughness, but has started to have problems in performance at high temperatures. Further, since it has been pointed out that halogenated gas generated at the time of incineration of PVC resin leads to environmental deterioration, it is being switched to non-halogen flame retardant resin that does not generate halogenated gas during combustion.

  As an electric wire coated with a non-halogen flame retardant resin, an electric wire coated with a resin composition obtained by adding a large amount of a flame retardant such as aluminum hydroxide or magnesium hydroxide to a polyolefin resin is generally used. However, they do not generate a halogenated gas during combustion, but they have a poor melt appearance due to a large amount of flame retardant, as compared to a single polyolefin. It has been regarded as a problem that the workability when assembling the product into a product is poor.

Polyamide resins have excellent mechanical properties, heat resistance and chemical resistance, and are used for various electric / electronic parts, mechanical parts and automobile parts mainly in injection molding and extrusion molding. However, since the flame retardant property of a polyamide resin alone is not sufficient, it is necessary to impart the flame retardant property in order to use it in a wire coating application. Various methods have been proposed by various companies as means for imparting such flame retardancy. For example, a resin composition composed of polyamide resin / melamine cyanurate has been proposed (Patent Document 1). Various proposals have also been made for electric wires made of a polyamide resin composition imparted with flame retardancy. For example, a large amount of magnesium hydroxide is added to a resin composition made of polyolefin / polyamide 12 / carboxylic acid-modified polyolefin. An electric wire coated with the resin composition has been proposed (Patent Document 2). Furthermore, the nitrogen content of the electric wire coated with a resin composition containing one or more of polyester resin, such as polyester plasticizer, ethylene vinyl acetate copolymer, ethylene ethyl acrylate, acrylic rubber or acrylonitrile butadiene rubber is controlled. Thus, it has been proposed to achieve both non-halogenation and flame retardancy (Patent Document 3). Wires coated with a resin composition comprising a thermoplastic polyurethane / polyamide elastomer / polymerized fatty polyamide / ethylene-vinyl acetate-vinyl alcohol copolymer and a nitrogen compound or phosphorus compound added thereto are also non-halogenated. Proposes both flame retardancy (Patent Document 4).
JP 53-31759 A JP-A-6-215644 JP 2001-354850 A JP 2001-49053 A

However, when the polyamide resin composition specifically described in Patent Document 1 is used, it is difficult to form a resin-coated electric wire from the viewpoint of melt viscosity. Moreover, although the electric wire of patent document 2 balances non-halogenation and a flame retardance, since it contains a flame retardant in large quantities, there exists a problem that a softness | flexibility and bending resistance are not enough. Moreover, since the electric wire described in Patent Document 3 contains a large amount of plasticizer, there is a problem in that the appearance is poor, for example, it may cause deposits on the discharge port of the die during extrusion molding. Moreover, although the electric wire described in Patent Document 4 has improved flexibility and bending resistance, there is a problem that heat resistance is inferior.

  In the present invention, it has been achieved as a result of investigations in view of the above facts, and the object is to achieve an appearance, flame retardancy, flexibility, flex resistance and heat resistance suitable for wire coating applications. It is an object of the present invention to provide a resin-coated electric wire coated with an excellent polyamide resin composition.

Thus, as a result of intensive studies to solve the above problems, the present inventors have found that the object can be achieved as a result of adding a specific amount of a triazine compound to a polyamide resin, and have reached the present invention. That is, the present invention
(1) (A) A relative viscosity of 1.5 to 7.0, a differential scanning calorimeter (DSC) is used, and a melting peak temperature measured at 20 ° C./min under a nitrogen atmosphere is 160 ° C. or higher. A polyamide resin composition for electric wire coating comprising 90 to 99.9 parts by weight of a certain polyamide resin and 0.1 to 10 parts by weight of (B) a triazine compound;
(2) a resin-coated electric wire coated with the polyamide resin composition according to (1),
(3) The resin-coated electric wire according to (2), wherein the polyamide resin plastic has a flexural modulus of 5.0 GPa or less,
Consists of.

    The resin-coated electric wire of the present invention has good appearance, flame retardancy, flexibility, bending resistance and heat resistance, and can be used in various applications. For example, electrical / electronic related applications, precision machine related equipment, Suitable for office equipment, automobile and vehicle related parts.

  Hereinafter, embodiments of the present invention will be described in detail.

  The polyamide resin (A) used in the present invention is a polyamide mainly composed of amino acids, lactams or diamines and dicarboxylic acids. Representative examples of the main constituents include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and paraaminomethylbenzoic acid, lactams such as ε-caprolactam and ω-laurolactam, and tetramethylenediamine. , Hexamethylenediamine, 2-methylpentamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, Metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, Bis (4-aminosi Chlohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, aminoethylpiperazine, aliphatic, alicyclic, aromatic Diamines, and adipic acid, speric acid, azelaic acid, sebacic acid, dodecanoic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid , 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid and the like, and aliphatic, alicyclic, and aromatic dicarboxylic acids. In the present invention, nylon homopolymer derived from these raw materials is used. Polymers or copolymers, each alone or in the form of a mixture It can be used.

  In addition, the polyamide resin used in the present invention needs to have a melting peak temperature of 160 ° C. or higher measured using a differential scanning calorimeter (DSC) at a temperature rising rate of 20 ° C./min and in a nitrogen atmosphere. From the viewpoint of heat resistance, the temperature is more preferably 170 ° C or higher. Specific examples include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polyhexamethylene sebamide (nylon 610), polyhexa Methylene dodecanamide (nylon 612), polyundecanamide (nylon 11), polydodecanamide (nylon 12), polycaproamide / polyhexamethylene adipamide copolymer (nylon 6/66), polycaproamide / polydodecanamide copolymer (Nylon 6/12), polycaproamide / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6T), polyhexamethylene adipa / Polyhexamethylene isophthalamide copolymer (nylon 66 / 6I), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), polyhexamethylene terephthalamide / polydodecanamide copolymer (nylon 6T / 12) , Polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I), polyxylylene adipamide (nylon XD6), polyhexamethylene terephthalamide / poly-2- Examples thereof include methylpentamethylene terephthalamide copolymer (nylon 6T / M5T), polynonamethylene terephthalamide (nylon 9T), and mixtures thereof.

  Particularly preferred polyamide resins include nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, nylon 6/66 copolymer and mixtures thereof.

  The degree of polymerization of the polyamide resin used in the present invention is such that the relative viscosity measured at 25 ° C. in a 98% concentrated sulfuric acid solution having a sample concentration of 0.01 g / ml is in the range of 1.5 to 7.0. Is required, and is more preferably in the range of 2.0 to 6.5 from the viewpoint of wire coating.

  The compounding amount of the polyamide resin used in the present invention is 90 to 99.9 parts by weight based on 100 parts by weight of the entire polyamide resin composition. The heat resistance peculiar to a polyamide resin can be exhibited by setting it as 90 weight part or more.

  In the polyamide resin composition for covering electric wires of the present invention, it is necessary to use (B) a triazine compound. The triazine compound refers to an azine having three nitrogen atoms in the ring. Specific examples thereof include (B) the triazine compound includes melamine cyanurate, melamine, dimelamine sulfate, melamine phosphate, polyphosphorus Examples thereof include melamine compounds such as melamine acid and ammonium polyphosphate. In the present invention, each can be used alone or in the form of a mixture. In this invention, the flame retardance required as an electric wire coating | covering material can be obtained by using the (B) triazine type compound. The added amount of the (B) triazine-based compound needs to be 0.1 to 10 parts by weight, and 1.0 to 8.0 parts by weight from the viewpoint of flame retardancy, flexibility and bending resistance. The range of is more preferable.

  The polyamide resin composition of the present invention has at least one selected from phenolic, phosphorus, thioether and amine compounds with respect to the polyamide resin in order to maintain high heat resistance and thermal stability. An antioxidant can be added. The blending amount of the antioxidant is preferably 0.01 parts by weight or more, particularly 0.02 parts by weight or more from the viewpoint of the heat resistance improving effect, and 5% by weight from the viewpoint of the gas component generated during molding. Part or less, particularly 1 part by weight or less. Moreover, you may use together using a phenolic type and phosphorus type antioxidant.

  As the phenolic antioxidant, a hindered phenolic compound is preferably used. Specific examples include triethylene glycol-bis [3-t-butyl- (5-methyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamide), tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate ] Methane, pentaerythrityltetrakis [3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-t-butyl- 4-hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) -trione, 1,1,3-tris (2-methyl-4 Hydroxy-5-tert-butylphenyl) butane, 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxy-) Phenyl) propionate, 3,9-bis [2- (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl] -2,4,8,10 -Tetraoxaspiro [5,5] undecane, 1,3,5-trimethyl-2,4,6-tris- (3,5-di-t-butyl-4-hydroxybenzyl) benzene and the like.

  Next, phosphorus antioxidants include bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, bis (2,4-di-t-butylphenyl). ) Pentaerythritol di-phosphite, bis (2,4-di-cumylphenyl) pentaerythritol di-phosphite, tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-bisphenylene phosphite, di-stearyl pentaerythritol di-phosphite, triphenyl phosphite, 3,5-dibutyl-4-hydroxybenzyl phosphite Examples include phonate diethyl ester.

  In addition, the polyamide resin of the present invention includes one kind of usual additives such as an ultraviolet absorber, a lubricant, a mold release agent, an antistatic agent, and a colorant including a dye / pigment as long as the object of the present invention is not impaired. More can be added.

The flexibility of the polyamide resin composition of the present invention is determined by the flexural modulus obtained by measuring and measuring a bending test piece obtained based on ISO 3167 (plastic-multipurpose test piece) based on ISO 178 (plastic-bending characteristic test method). Can be evaluated. In addition, the flexural modulus of the polyamide resin composition is preferably 5.0 GPa or less in an absolutely dry state (water absorption rate 0.1% or less) in a 23 ° C. atmosphere, and 4.0 GPa or less from the viewpoint of the flexibility of the electric wire. More preferred. When it is higher than 5.0 GPa, the flexibility of the resin-coated electric wire is insufficient, and the electric wire may not be bundled and assembled to the product.
In the resin-coated electric wire of the present invention, it is necessary to coat the electric wire with the polyamide resin composition. By covering the electric wire with the above polyamide resin composition, compared to the case where the electric wire is covered with polyolefin or the like to which a large amount of conventional flame retardant is added while having heat resistance and flame retardancy, It can be flexible.

  The kneader used for the production of the polyamide resin composition of the present invention is a commonly known melt kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll. A typical example is a method in which a resin, (B) a triazine compound, and other additives are supplied and kneaded at a melting temperature of the polyamide resin at a processing temperature of 5 to 60 ° C. The processing temperature is 300 ° C. When the temperature exceeds 1, the triazine-based compound is decomposed, so that melt kneading is preferably performed at 300 ° C. or lower. Further, in order to increase the dispersibility of the triazine compound, it is preferable that the shearing force is relatively strong. Specifically, a method of kneading using a twin screw extruder so that the resin temperature at the time of kneading becomes the melting peak temperature of the polyamide resin +10 to 20 ° C. can be preferably used. At this time, there are no particular restrictions on the mixing order of the raw materials, a method in which all raw materials are blended and then melt-kneaded by the above method, a part of the raw materials are blended and melt-kneaded by the above method, and the remaining raw materials are further blended Any method may be used, such as a method of melt kneading, or a method of mixing a part of raw materials and mixing the remaining raw materials using a side feeder during melt kneading with a single or twin screw extruder. Moreover, about a small amount additive component, after kneading | mixing another component by said method etc. and pelletizing, it is also possible to add before shaping | molding and to use for shaping | molding.

  The method for producing the resin-coated electric wire of the present invention is not particularly limited, but the polyamide resin composition is supplied to a generally known melt-kneader such as a single-screw or twin-screw extruder, and the melting peak of the polyamide resin +5 to 60 ° C. Examples thereof include a method in which the wire is surrounded and extruded in a die after being kneaded at the processing temperature, a method in which the wire is covered by a method in which the wire is surrounded and extruded at the die outlet, and the like. Moreover, the cooling means of the covered wire immediately after coming out of the die is not particularly limited, but a water cooling method is preferably used from the viewpoint of cooling efficiency and stability.

  In addition, the resin-coated electric wire of the present invention may take means for suppressing water absorption in order to prevent dimensional change due to water absorption of the polyamide resin and a decrease in insulation resistance within a range that does not impair the object of the present invention. Examples of such a method include a method of laminating a resin having no water absorption on the outermost layer of the resin-coated electric wire by multilayer extrusion molding, a coating method or the like, a method using a polyamide having a low water absorption rate as a polyamide, and other resins having a low water absorption. And alloying.

  The resin-coated electric wire of the present invention is particularly preferably used for applications such as electrical / electronic related applications, precision machine related equipment, office equipment, automobile / vehicle related parts.

The present invention will be described more specifically with reference to the following examples. The present invention is not limited to these examples.
In the following examples and comparative examples, the material properties were measured by the following method.

[Flame retardance]
The resin-coated electric wire was measured based on ISO 6722 (fire resistance propagation test). The flame extinguished within 70 seconds, the sample remaining 55 mm or more above the unburned sample was circled, the flame extinguished within 70 seconds, and the sample 55 mm to 50 mm remaining unburned was marked Δ, within 70 seconds The case where the flame was not extinguished and / or the case where 50 mm or more of the sample burned was marked as x.

[Bending elastic modulus]
Using an injection molding machine (PS60E manufactured by Nissei Kogyo Co., Ltd.), an ISO 3167 multipurpose test piece A type was prepared under conditions of a cylinder temperature of 270 ° C. and a mold temperature of 80 ° C., and the ISO 178 method (test speed 2 mm / min, The distance was measured based on the distance between fulcrums of 64 mm.

[Flexibility]
An operation of bending a resin-coated electric wire having a sample length of 100 mm and a sample diameter of 1.2 mm to 180 ° and returning it to the original position (0 °) was repeated, and the state after being bent 30 times was observed. The case where the surface of the bent portion was not whitened after the specified number of times was indicated as “◯”, the case where it was whitened 25 to 30 times, “Δ”, and the case where it was whitened 25 times or less as “X”.

[Heat-resistant]
A resin-coated wire having a sample length of 100 mm and a sample diameter of 1.2 mm was heat-treated in an oven at 150 ° C. for 1 hour, then bent to 180 ° and returned to the original position (0 °). Observe the state after 30 times of bending, ○ that does not cause cracks on the surface of the bent part after the specified number of times, Δ that has cracked 25 to 30 times, Δ that has cracked 25 times or less X.

[Relative viscosity]
(A) The relative viscosity in 98% sulfuric acid was measured for the polyamide resin based on JIS-K6810.

[appearance]
The appearance of the resin-coated electric wire after extrusion molding was visually observed. ◯ for those with no appearance defects, such as those with a uniform thickness without uneven thickness, those with almost no surface irregularities, △ for those with a slight appearance defect, and those with a large appearance defect × It was.

[Melting peak temperature]
Using a differential scanning calorimeter (DSK7 manufactured by PERKIN-ELMER), the temperature was increased at a rate of 20 ° C./min in a nitrogen atmosphere. Moreover, the melting peak temperature of the polyamide resin was measured for the resin composition mixed with multiple components.

[Example 1]
(A) Polyamide 6 resin polymerized according to a conventional method (Amilan manufactured by Toray Industries, Inc., relative viscosity 4.4) and melamine cyanurate compound (MCA C-0 manufactured by Mitsubishi Chemical Co., Ltd.) in the ratios shown in Table 1. After dry blending, the cylinder temperature is set to 250 ° C. with a twin-screw extruder (Tex30 type, manufactured by Nippon Steel Works), melt kneaded at a screw speed of 200 rpm, and cooled with a water-cooled bath. Pelletized with a cutter. Thereafter, vacuum drying was performed in a vacuum state using a vacuum dryer at a processing temperature of 80 ° C. and a processing time of 12 hours, and the moisture content was adjusted to 0.07% or less.
In addition, the polyamide resin composition was applied to a copper wire having a conductor outer diameter of 0.813 mm, the cylinder temperature was set to 250 ° C. using a single-screw extruder (φ40 mm, manufactured by Shinko-Machinery), and the wire was taken out in the die. The resin-coated electric wire was manufactured by adjusting the screw rotation speed and the take-up speed so that the thickness was 0.2 mm and the outer diameter was 1.2 mm. Table 1 shows the evaluation results of the samples. A resin-coated electric wire excellent in appearance, flame retardancy, flexibility, bending resistance and heat resistance could be obtained.

[Example 2]
(A) Polyamide 6 / polyamide 12 copolymer resin (Amilan manufactured by Toray Industries, Inc., relative viscosity 2.8) and melamine cyanurate compound (MCA C-0 manufactured by Mitsubishi Chemical Co., Ltd.) with the composition shown in Table 1, A resin-coated wire was obtained in the same manner as in Example 1. The evaluation results of the samples are as shown in Table 1. A resin-coated electric wire excellent in appearance, flame retardancy, flexibility and bending resistance could be obtained.

[Comparative Example 1]
(A) Resin-coated electric wires were obtained in the same manner as in Example 1 except that magnesium hydroxide was added to the polyamide resin in place of the melamine cyanurate compound in the composition shown in Table 1. The evaluation results of the samples are as shown in Table 1. Magnesium hydroxide cannot obtain sufficient flame retardancy with an addition amount of 10% or less.

[Comparative Example 2]
Polyamide 6 / polyolefin alloy resin (Amilan U121 manufactured by Toray Industries, Inc.) and polyester plasticizer (New Nippon Rika Co., Ltd., Sanso Sizer N-400) were used in the same manner as in Example 1 with the composition shown in Table 1. A resin-coated wire was obtained. The evaluation results of the samples are as shown in Table 1. Due to the large amount of plasticizer, the appearance was poor.

[Comparative Example 3]
Polyamide elastomer (PEBAX3533SA manufactured by Elf Atchem Co., Ltd.) and dimelamine sulfate (Apinon 901 manufactured by Sanwa Chemical Co., Ltd.) were dry blended at the ratio shown in Table 1, and then a twin screw extruder (Nippon Steel Works, Ltd.) ) Manufactured by TEX30), the cylinder temperature was set to 180 ° C., melt kneaded at a screw speed of 200 rpm, cooled with a water-cooled bath, and then pelletized with a strand cutter. Thereafter, vacuum drying was performed in a vacuum state using a vacuum dryer at a processing temperature of 80 ° C. and a processing time of 12 hours, and the moisture content was adjusted to 0.07% or less.
Further, the polyamide elastomer resin composition is applied to a copper wire having a conductor outer diameter of 0.813 mm, and the cylinder temperature is set to 180 ° C. using a single screw extruder (φ40 mm, manufactured by Shinko Machinery Co., Ltd.). The resin-coated electric wire was produced by surrounding and extruding and adjusting the screw rotation speed and the take-up speed so that the wall thickness was 0.2 mm and the outer diameter was 1.2 mm. Table 1 shows the evaluation results of the samples. The flame retardancy and heat resistance were poor.

[Comparative Example 4]
Low-density polyethylene resin (Ultzex 20100J manufactured by Mitsui Chemicals, Inc., density = 0.920 g / m ³ ) 100 parts by weight, maleic anhydride 0.2 parts by weight, 2,5-di (tert-butylperoxy) hexane 0.1 parts are dry blended, with a twin screw extruder (TEX30 type, manufactured by Nippon Steel), the cylinder temperature is set to 220 ° C., melt kneaded at a screw speed of 200 rpm, and cooled with a water-cooled bath. And then pelletized with a strand cutter to obtain a maleic anhydride-modified polyethylene resin (melt index (MI) 190 ° C. = 3 g / 10 min, density = 0.920 g / m ³ ). Further, the above maleic anhydride polyethylene resin, polyamide 12 resin (Amilan manufactured by Toray Industries, Inc.), high-density polyethylene resin (Hi-Zex 6200B manufactured by Mitsui Chemicals, Inc., MI 190 ° C. = 0.4 g / 10 min, density = 0.958 g / M ³ ), stearic acid, 4,4′thiobis- (6-tert-butyl-4-methylphenol) (compound 1) at a ratio shown in Table 1, and then dry blended (Nippon Steel Works) (TEX30 type manufactured by Co., Ltd.), the cylinder temperature was set to 220 ° C., melt-kneaded at a screw speed of 200 rpm, cooled with a water-cooled bath, and then pelletized with a strand cutter. Thereafter, vacuum drying was performed in a vacuum state using a vacuum dryer at a processing temperature of 80 ° C. and a processing time of 12 hours, and the moisture content was adjusted to 0.07% or less.

In addition, the resin composition is applied to a copper wire having a conductor outer diameter of 0.813 mm, the cylinder temperature is set to 220 ° C. using a single screw extruder (φ40 mm manufactured by Shinko Machinery Co., Ltd.), and the wire is surrounded in the die. Then, the screw rotation speed and the take-up speed were adjusted so that the wall thickness was 0.2 mm and the outer diameter was 1.2 mm, and a resin-coated electric wire was produced.
Table 1 shows the evaluation results of the samples. The heat resistance was poor.

[Examples 3 to 4]
(A) A resin-coated wire was obtained in the same manner as in Example 1 except that the blending composition of the polyamide resin and the melamine cyanurate compound (MCA C-0 manufactured by Mitsubishi Chemical Corporation) was different.
The evaluation results of each sample are as shown in Table 2. A resin-coated electric wire excellent in appearance, flame retardancy, flexibility and bending resistance could be obtained.

[Comparative Examples 5-6]
(A) A resin-coated electric wire was obtained in the same manner as in Example 1 except that the blending composition of the polyamide resin and the melamine cyanurate compound (MCA C-0 manufactured by Mitsubishi Chemical Corporation) was different.
The evaluation results of each sample are as shown in Table 2. When the melamine cyanurate compound is smaller than 0.1% by weight, sufficient flame retardancy cannot be obtained, and when it exceeds 10% by weight, the bending resistance is inferior.

[Examples 5 to 6]
(A) A resin-coated wire was obtained in the same manner as in Example 1 except that the relative viscosity of the polyamide resin composition was different.
The evaluation results of each sample are as shown in Table 3. A resin-coated electric wire excellent in appearance, flame retardancy, flexibility and bending resistance could be obtained.

[Comparative Examples 7-8]
(A) A resin-coated wire was obtained in the same manner as in Example 1 except that the relative viscosity of the polyamide resin was different.
The evaluation results of each sample are as shown in Table 3. When the relative viscosity was less than 1.5, the thickness was not stable, so the appearance was poor and the flex resistance was inferior. On the other hand, when the relative viscosity was 8.0 or more, a wavy pattern was generated due to melt fracture and the appearance was poor.

Claims (3)

(A) Polyamide resin having a relative viscosity of 1.5 to 7.0, a temperature rise rate of 20 ° C./min using a differential scanning calorimeter (DSC), and a melting peak temperature of 160 ° C. or higher measured in a nitrogen atmosphere. A polyamide resin composition for covering electric wires, comprising 90 to 99.9 parts by weight and (B) 0.1 to 10 parts by weight of a triazine compound. A resin-coated electric wire coated with the polyamide resin composition according to claim 1. The resin-coated electric wire according to claim 2, wherein the polyamide resin composition has a flexural modulus of 5.0 GPa or less.