JP2007329013A - Flame-retardant insulated wire and wire harness - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant insulated wire that has a double-layered structure in a coating layer of an insulator and is lightweight and excellent in heat resistance, flame retardancy, and mechanical properties or the like. <P>SOLUTION: In the flame-retardant insulated wire; a primary coating layer and a secondary coating layer are applied on a conductor from its inside, the primary coating layer is composed of a polyolefin-based resin composition, and the secondary coating layer is composed of a flame-retardant resin composition that is composed by adding 80-100 pts.mass of a hydrated metal compound and 30-50 pts.mass of a triazine-based flame retarder to 100 pts.mass of a polyolefin-based resin admixture composed of 80-95 pts.mass of polypropylene and 20-5 pts.mass of polyethylene. By this, it is possible to obtain the wire that has the double-layered structure in the coating layer of the insulator; and is lightweight and excellent in heat resistance, flame retardancy, and mechanical properties or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flame-retardant insulated electric wire (including a cable) and a wire harness that are lightweight and excellent in heat resistance, flame retardancy, mechanical properties, and the like.

  Various wire harnesses are used in automobiles (vehicles) for connection between electrical devices. In the case of this wire harness, various characteristics are required although it varies depending on the use location (part). For example, in recent years it is light in terms of improving the fuel efficiency of vehicles, and is not as high as around the engine room or in the engine room, but it is quite hot under the summer sun in the vehicle side wall, etc., so it can withstand high temperature conditions. Sexuality may be required. In addition, the wire harness itself has high flame resistance that does not cause the spread of fire, there is no generation of toxic gas at the time of ignition or combustion, and the bent part is white at the time of assembly or wiring. It is also necessary that the whitening phenomenon is difficult to occur, and that mechanical strength such as sufficient wear resistance is provided against pulling and rubbing after wiring.

  In such automobile wire harnesses, the most common ones in the past are those using polyvinyl chloride (PVC) as the insulator (coating material) of the constituent insulated wires. However, in the case of vinyl chloride, high flame retardancy can be obtained, but toxic gas (hydrogen chloride) is caused by chlorine element (halogen element) in the resin during combustion at the time of accident or incineration after scrapping. There was a serious drawback of generating gas.

For this reason, various types of non-halogen type resins that do not contain chlorine element have been proposed as base resins for insulators of constituent insulated wires (Patent Documents 1 and 2). For example, polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene / propylene / gen copolymer (EPDM), polypropylene (PP) Such resins are often used.
Japanese Patent Laid-Open No. 10-294021 JP 2000-086858 A

  However, since these resins are flammable and inferior in flame retardancy compared to polyvinyl chloride, it is necessary to add a flame retardant. Of course, considering the prevention of the generation of toxic gas during combustion, the flame retardant used must be non-halogen. Examples of such a flame retardant include hydrated metal compounds (metal hydrates) such as magnesium hydroxide and aluminum hydroxide. In recent years, these can be used alone or, if necessary, other flame retardants. Such as antimony oxide, zinc borate, and phosphate ester flame retardants.

  However, in the case of a hydrated metal compound, it is necessary to add a considerable amount to the base resin in order to ensure the desired flame retardancy. Of course, the higher the required flame retardancy, the more the additive amount must be increased. As the amount of the hydrated metal compound is increased, there arises a problem that the properties of the insulator by the resin composition, for example, the mechanical strength is lowered. In addition, since the specific gravity of the hydrated metal compound itself is large, the specific gravity (for example, 1.2 or more) of the insulator portion is also increased, which makes it difficult to reduce the weight of the wire harness itself.

  Furthermore, for resins such as polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene / propylene / gen copolymer, depending on the specifications of the wire harness, a machine with heat resistance or wear resistance may be used. There was a problem that the strength and the like were insufficient.

  In contrast, polypropylene is relatively inexpensive, has a small specific gravity, is excellent in terms of heat resistance and mechanical strength, and can be said to be a desirable resin, but it is difficult to mix a flame retardant well in production, There were problems such as whitening due to bending.

  Under such circumstances, the present inventors have adopted a two-layer structure as an insulating covering layer in obtaining an automobile wire harness with high heat resistance requirements (such as ISO 6722 standard 85 ° C or 100 ° C heat resistant grade). In addition, as the base resin on the side of the secondary coating layer on the outside of the insulator, polypropylene having excellent characteristics such as heat resistance and wear resistance is added, and by adding an appropriate amount of polyethylene, polypropylene alone This makes it possible to smoothly mix flame retardants, which was difficult to achieve.

  In addition, in the flame retardant by mixing this flame retardant, the combined use of a hydrated metal compound and a triazine flame retardant can eliminate the harmful effects of adding a large amount of these flame retardants alone. It has been found that an excellent insulator having the characteristics maintained can be obtained, the specific gravity can be suppressed to 1.2 or less, and the whitening phenomenon can be improved by the combined use of attack polypropylene.

  The present invention has been made from this viewpoint, and can provide a flame-retardant insulated wire and a wire harness that are lightweight and excellent in heat resistance, flame retardancy, mechanical properties, and the like.

  In the first aspect of the present invention, a primary coating layer and a secondary coating layer are applied on the conductor from the inside thereof, the primary coating layer is made of a polyolefin resin composition, and the secondary coating layer is made of polypropylene 80- Flame retardancy in which 80 to 100 parts by mass of a hydrated metal compound and 30 to 50 parts by mass of a triazine flame retardant are added to 100 parts by mass of a polyolefin resin mixture comprising 95 parts by mass and 20 to 5 parts by mass of polyethylene. A flame-retardant insulated wire comprising a resin composition.

  The present invention according to claim 2 is the flame-retardant insulated electric wire according to claim 1, wherein the hydrated metal compound is magnesium hydroxide.

  The present invention according to claim 3 is the flame-retardant insulated wire according to claim 1, wherein the triazine flame retardant is melamine cyanurate.

  The present invention according to claim 4 is characterized in that, among 80 to 95 parts by mass of the polypropylene, 5 to 30 parts by mass is an attack polypropylene having a surface hardness measured by ASTM-D2240 of 60 or less. It exists in the flame-retardant insulated wire of 2 or 3.

  The present invention according to claim 5 is the flame-retardant insulated electric wire according to claim 1, wherein the polypropylene has a melting point of 160 ° C or higher.

  A sixth aspect of the present invention is a wire harness using the flame-retardant insulated electric wire according to any one of the first to fifth aspects.

  According to the flame-retardant insulated wire of the present invention, the insulator on the conductor has a two-layer structure, and the primary coating layer is composed of a polyolefin resin composition mainly composed of a base resin not containing a flame retardant. It is possible to obtain an excellent insulator layer without any decrease in the thickness. In addition, the secondary coating layer on the outside of the insulator uses a polyolefin resin mixture composed of 80 to 95 parts by weight of polypropylene and 20 to 5 parts by weight of polyethylene as a base resin. Can be mixed smoothly. As this flame retardant, triazine flame retardant and hydrated metal compound are used in combination, so the upper limit addition amount and total addition amount of each flame retardant can be reduced. It is possible to prevent deterioration of resin properties such as mechanical strength. Moreover, the specific gravity can be suppressed to 1.2 or less by the combined addition of both flame retardants. Furthermore, if an appropriate amount of attack polypropylene is used in combination with the base resin polypropylene, the whitening phenomenon can be improved.

  According to the wire harness of the present invention, by assembling the above-mentioned flame-retardant insulated wire, light weight, good heat resistance, wear resistance, hot water resistance, etc. are maintained, and the whitening phenomenon has been improved. An excellent wire harness can be obtained.

  FIG. 1 shows an example of a flame-retardant insulated wire according to the present invention. In the figure, reference numeral 1 denotes a conductor, and reference numerals 2a and 2b denote a primary covering layer and a secondary covering layer formed on the conductor 1, respectively. The conductor 1 can be a single wire, but usually a twisted wire (for example, 19 / 0.12: 19 thin wires having an outer diameter of 0.12 mm) twisted together a plurality of thin wires (for example, tin-plated annealed copper stranded wires). To use).

  The base resin of the polyolefin-based resin composition used for the primary coating layer of the insulator is not particularly limited, and may be polypropylene (PP), polyethylene (PE), ethylene-vinyl acetate copolymer depending on the use and required specifications of the electric wire. (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene / propylene / gen copolymer (EPDM) and other commonly used resins may be mentioned. These may be used alone or in combination as appropriate.

However, it is preferable to use polypropylene in order to obtain mechanical properties such as high heat resistance and abrasion resistance, and good hot water resistance. This polypropylene is not particularly limited, and examples thereof include a homopolymer, a random copolymer polymerized with ethylene, a block copolymer, and a mixture thereof. In actual use, for example, in the case of a wire harness, an appropriate amount may be selected according to required heat resistance specifications (85 ° C or 100 ° C heat-resistant grade of ISO 6722 standard). In order to adapt the wire harness to the heat resistant grade of 85 ° C. or 100 ° C. of ISO 6722 standard, a material having a melting point of 160 ° C. or higher should be used even if polypropylene is used alone or in combination of several kinds. .
Examples of such commercially available products include B701WB (Prime Polymer Co., Ltd., Block PP, melting point 163 ° C., MFR 0.5), E111G (Prime Polymer Co., Ltd., homo PP, melting point 160 to 165 ° C., MFR 0.51), etc. Can be mentioned.

  The secondary coating layer of the insulator is a portion that becomes the outer side of the electric wire, and as the base resin of the polyolefin-based resin mixture used therefor, a material having polypropylene as a main component and an appropriate amount of polyethylene added is used. Specifically, a polyolefin resin mixture composed of 80 to 95 parts by mass of polypropylene and 20 to 5 parts by mass of polyethylene is used. In this blending, the total mass part of polypropylene and polyethylene is 100 parts by mass.

  The main purpose of adding polyethylene to the polypropylene is to promote mixing of the flame retardant with the polypropylene. By promoting this mixing (blending), deterioration of resin properties can be prevented. Moreover, the hardness of polypropylene itself is relieved and the improvement effect of the whitening phenomenon at the time of a bending is also acquired. The addition of 20 to 5 parts by mass of polyethylene with respect to 80 to 95 parts by mass of polypropylene exceeds the original characteristics of polypropylene (mechanical characteristics such as heat resistance and wear resistance) when it exceeds 20 parts by mass. This is because the above-mentioned effects cannot be obtained because the amount is less than 5 parts by mass.

  The polypropylene that can be used in the secondary coating layer is not particularly limited, and as described above, homopolymers, random copolymers polymerized with ethylene, block copolymers, and mixtures thereof can be exemplified. . In actual use, as described above, for example, in the case of a wire harness, an appropriate amount may be selected in accordance with required heat resistance specifications (85 ° C or 100 ° C heat-resistant grade of ISO 6722 standard). In order to adapt the wire harness to the heat resistant grade of 85 ° C. or 100 ° C. of ISO 6722 standard, a material having a melting point of 160 ° C. or higher should be used even if polypropylene is used alone or in combination of several kinds. . Examples of the commercially available products include B701WB (manufactured by Prime Polymer Co., Ltd., block PP, melting point 163 ° C., MFR 0.5), E111G (manufactured by Prime Polymer Co., Ltd., homo PP, melting point 160 to 165 ° C., MFR 0.51) and the like. Can be mentioned.

  Moreover, as polyethylene added to the polypropylene of the secondary coating layer, the polyethylene includes high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), and linear low density polyethylene (LLDPE). Any of these may be used, and a mixture thereof may be used. However, in view of the effect of promoting the mixing of the flame retardant, it is desirable to use LDPE or LLDPE which is soft in nature because of its low crystallinity and high acceptability of the flame retardant. Examples of such commercially available products include C150 (manufactured by Ube Maruzen Polyethylene Co., Ltd., LDPE), 2015M (manufactured by Prime Polymer Co., Ltd., LLDPE), and the like.

  When a resin composition mainly composed of polypropylene is coated as an insulator for an insulated wire for a wire harness, when a bending stress is applied, a whitening phenomenon occurs in which the surface turns white, depending on the bending curvature. There is. In particular, it is necessary to suppress the occurrence of the whitening phenomenon on the secondary coating layer side that is the surface side of the insulator in the present invention. This whitening phenomenon is improved to some extent by the addition of polyethylene (softening effect), as is apparent from test data described later. The secondary coating layer can also be improved by adding a triazine flame retardant. However, in order to improve more positively, in order to prevent the whitening phenomenon from occurring even when bending with a small curvature, it is preferable that 5 to 30 of the blending amount (80 to 95 parts by mass) of polypropylene. The mass part may be replaced with an attack polypropylene having a surface hardness measured by ASTM-D2240 of 60 or less.

  The effect of preventing the whitening phenomenon can be obtained by this replacement addition. The attack type is soft in characteristic (surface hardness is 60 or less), and is compatible with the amorphous part of the base polypropylene and softens. It is presumed that. Here, the blending amount is set to 5 to 30 parts by mass. If the amount is less than 5 parts by mass, the effect of preventing the whitening phenomenon is hardly obtained, and conversely, if it exceeds 30 parts by mass, the resin This is because the mechanical strength of the material becomes lower. In addition, attack polypropylene is a stereospecific substance of polypropylene in which methyl groups are randomly arranged with respect to the main chain of the polymer, and is usually an oily one. In the present invention, a resin pellet is used. . Examples of the resin pelletized commercial product include T3527 (manufactured by Sumitomo Chemical Co., Ltd.) and T1712 (manufactured by Sumitomo Chemical Co., Ltd.).

  In the secondary coating layer of the present invention, for flame retardancy, 80 to 100 parts by mass of a hydrated metal compound (metal hydrate) and 30 to 50 parts by mass of a triazine flame retardant with respect to 100 parts by mass of the polyolefin resin mixture. Add parts.

  Examples of the hydrated metal compound include magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like. These can also be used 1 type or in mixture of 2 or more types. In the case of a hydrated metal compound, a surface treated with a silane coupling agent, a titanate coupling agent, a higher fatty acid or the like is preferable in terms of dispersibility and affinity. This commercially available product includes, for example, Kisuma 5A (manufactured by Kyowa Chemical Industry Co., Ltd., surface-treated with stearic acid), Kisuma 5P (manufactured by Kyowa Chemical Industry Co., Ltd., surface-treated with a silane coupling agent), Kisuma 5 ( Kyowa Chemical Industry Co., Ltd., untreated surface).

  Examples of the triazine flame retardant include melamine cyanurate. In the case of melamine cyanurate, those having a small average particle diameter of 10 μm or less, preferably 7 μm are preferable. Further, those subjected to surface treatment with a higher fatty acid, a silane coupling agent, polyvinyl alcohol, colloidal silica or the like are preferable in terms of dispersibility and affinity for the base resin. Examples of the commercially available products include MC860 (manufactured by Nissan Chemical Industries, surface-treated with polyvinyl alcohol), MC440 (manufactured by Nissan Chemical Industries, Ltd., surface-treated with colloidal silica), and the like.

Since both these flame retardants are used in combination, the upper limit addition amount and the total addition amount of each flame retardant may be small. As a result, it is possible to prevent adverse effects due to the addition of a large amount, for example, deterioration of resin characteristics such as insulation characteristics and mechanical strength such as pulling and rubbing. Further, since the addition amount of the hydrated metal compound having a large specific gravity is small, the specific gravity can be suppressed to 1.2 or less.

  Specifically, the addition amount of the hydrated metal compound is set to 80 to 100 parts by mass with respect to 100 parts by mass of the polyolefin-based resin mixture, for example, depending on the required flame retardancy, but for example 85 of ISO 6722 standard In order to pass the heat resistance grade of 100 ° C. or 100 ° C., the desired flame retardancy cannot be obtained if it is less than 80 parts by mass, and if it exceeds 100 parts by mass, the characteristics of the base resin will deteriorate.

  Further, the amount of the triazine flame retardant added is 30 to 50 parts by mass with respect to 100 parts by mass of the polyolefin resin admixture, although it depends on the required flame retardancy, for example, 85 ° C. of ISO 6722 standard. Alternatively, in order to pass the heat resistant grade of 100 ° C., the desired flame retardancy is ensured and the adverse effect on the base resin is minimized. However, if the addition amount is less than 30 parts by mass, the amount is too small to obtain desired flame retardancy, and if it exceeds 50 parts by mass, an adverse effect on the base resin will appear.

  The polyolefin resin composition and the base resin of the primary coating layer and secondary coating layer of the present invention having such a composition are used in accordance with the application and required specifications, if necessary, an antioxidant, an ultraviolet degradation inhibitor, a processing. Additives such as auxiliaries, color pigments, carbon black, and copper damage inhibitors can be added as appropriate.

  In the present invention, in order to produce a wire harness for an automobile using the polyolefin resin composition or the flame retardant resin composition of the primary coating layer or the secondary coating layer, first, an insulator is formed on the conductor by an extruder. As described above, the primary coating layer and the secondary coating layer are extruded and coated. At this time, each of them may be extruded alone, but preferably they are extruded simultaneously. At this time, the thicknesses of both coating layers depend on the outer diameter of the conductor. For example, when the outer diameter of the conductor stranded wire (19 / 0.12) is 1.0 mm, the thickness is about 0.20 to 0.30 mm. It is good to do. Of these, the thickness of the outer secondary coating layer is preferably about 0.10 mm. If the secondary coating layer is thick, flame retardancy and reduction of the whitening phenomenon can be obtained, and if it is thin, scraping properties such as rubbing deteriorate. On the other hand, when the thickness of the secondary coating layer is large, mechanical properties such as heat resistance and abrasion resistance, and hot water resistance can be improved. For this reason, it is necessary to adjust the thickness between both coating layers according to a use and a requirement specification. With this configuration, it is possible to obtain a flame-retardant insulated wire having a two-layer structure that is lightweight and has excellent heat resistance, flame retardancy, mechanical properties, and the like. A wire harness for an automobile can be obtained by appropriately assembling a plurality of the flame-retardant insulated wires in accordance with the form of the harness.

  The weight reduction of the flame-retardant insulated wire of this wire harness is obtained by the fact that the addition amount of the hydrated metal compound having a large specific gravity is small (the upper limit addition amount is about the same as the base resin). Of course, the use of polypropylene itself, which is the main component of the base resin, also contributes to this weight reduction. That is, polypropylene is a resin having the lowest specific gravity (about 0.90 to 0.91) among the resins. In addition, the standard of weight reduction is 1.2 or less specific gravity.

  Further, in the case of the secondary coating layer side, the whitening phenomenon can be improved particularly by adding polyethylene or a triazine flame retardant or using an attack polypropylene.

<Examples and comparative examples>
First, a flame-retardant insulated wire of a sample having an insulator composed of a two-layer structure of a primary coating layer and a secondary coating layer was manufactured using a base resin having the composition shown in Tables 1 to 4 (Example) 1-10, Comparative Examples 1-7). The electric wire of each sample has a conductor (19 / 0.12) covered with an insulator having a thickness of 0.25 mm with two layers of a primary coating layer and a secondary coating layer, and an outer diameter of 1.04 mm. Polypropylene of the polyolefin-based flame retardant resin composition used is B701WB (Prime Polymer, Block PP, melting point 163, MFR 0.5), polyethylene is C150 (Ube Maruzen Polyethylene, LDPE), and attack polypropylene is T3527 ( Sumitomo Chemical Co., Ltd.), melamine cyanurate of triazine flame retardant MC860 (Nissan Chemical Industry Co., Ltd., surface treated with polyvinyl alcohol), magnesium hydroxide of hydrated metal compound Kisuma 5A (manufactured by Kyowa Chemical Industry Co., Ltd., Antioxidants are Irganox MD1024 (manufactured by Ciba Specialty Chemicals) and Irganox 1010 (manufactured by Ciba Specialty Chemicals). In addition, the numerical value of the compounding quantity in a table | surface shows a mass part. In the table, the primary coating layer is simply indicated as “primary”, and the secondary coating layer is simply indicated as “secondary”.

  The electric wire of each sample is subjected to a characteristic test, and its characteristics (tensile breaking strength, tensile breaking elongation, flame retardancy, scrape, hot water resistance, whitening phenomenon by bending (bending curvature: φ6 mm, φ3 mm, φ1 mm)) are obtained. It was. Each characteristic was evaluated as follows.

  For <Tensile Breaking Strength>, a tensile breaking strength test was performed at a tensile speed of 200 mm / min and a marked line distance of 20 mm. And when the tensile strength at break was 10 Mpa or more, “pass” was displayed, and less than 10 Mpa was displayed as “fail”.

  For <Tensile rupture elongation>, a tensile rupture elongation test was performed at a tensile rate of 200 mm / min and a marked line length of 20 mm. And when tensile elongation at break was 150% or more, it was displayed as “pass”, and less than 150% was displayed as “fail”.

  For <Flame Retardancy>, a 45 [deg.] Inclined combustion test corresponding to the heat resistant grade of 85 [deg.] C. or 100 [deg.] C. of ISO 6722 standard was performed. And what extinguishes within 70 seconds and the upper 50 mm or more remaining in the 500 mm electric wire is displayed as “pass”, extinguishes in more than 70 seconds, and remains less than 50 mm upper in the 500 mm electric wire Is displayed as “failed”.

  About <scrape>, the test used as an index of abrasion resistance based on JASO-D611 standard was done. That is, a wear test was performed by reciprocating a needle of φ0.45 mm with a load of 7 N on the insulator of the electric wire, and the number of times until the needle contacted the inner conductor at that time was measured. In the actual measurement, in order to eliminate the influence of the uneven thickness of the insulator, it was rotated by 90 ° and the wear test was performed three times from four directions (up, down, left and right) of the outer periphery of the insulator (total 12 times test). The number (average value) of 30 times or more was displayed as “pass”, and less than 30 times was displayed as “fail”.

About <warm water resistance>, the warm water resistance test based on ISO6722 standard was done, and it evaluated by the presence or absence of the dielectric breakdown of an electric wire. That is, a sample electric wire was wound around a 6 mm mandrel and immersed in 1% salt water at 85 ° C., and a direct current of 48 V was charged and continued for 35 days. The volume resistance value (85 ° C) after immersion in warm water is 10 ⁹ Ωmm or more, 1 Kv charge is performed for 1 minute, and even if the pressure is increased to 3 Kv after that, “pass” is displayed. When the volume resistance value (85 ° C.) is less than 10 ⁹ Ωmm or when dielectric breakdown occurs, “fail” is indicated.

  As for <whitening phenomenon>, an electric wire was wound around a mandrel of φ6 mm, φ3 mm, and φ1 mm, and the presence or absence of the whitening phenomenon in the insulator with the corresponding bending curvature was observed.

  As apparent from Tables 1 to 4 above, in the case of the flame-retardant insulated wire of the present invention (Examples 1 to 10), it can be seen that all the characteristics are good. Further, it can be seen that when a large amount of specific-specific attack polypropylene is added to the base resin polypropylene (Examples 8 to 10), the whitening phenomenon can be effectively prevented.

On the other hand, in the case of the flame-retardant insulated wire lacking the conditions of the present invention (Comparative Examples 1 to 7), it can be seen that there is a problem in any point.
That is, it can be seen that Comparative Example 1 is a case where the secondary coating layer has a small amount of triazine flame retardant, and the flame retardancy is insufficient. Comparative Example 2 is a case where the secondary coating layer has a large amount of triazine-based flame retardant, and it can be seen that there are problems with scrape and hot water resistance. The comparative example 3 is a case where there are few hydrated metal compounds of the flame retardant of a secondary coating layer, and it turns out that flame retardance is inadequate. Comparative Example 4 is a case where there are many hydrated metal compounds of a secondary coating layer, and it turns out that there is a problem in scrape or warm water resistance.

  Comparative Example 5 is a case where polyethylene is not added to the polypropylene of the secondary coating layer, and it can be seen that there are problems except for flame retardancy. The comparative example 6 is a case where there is too much addition amount of polyethylene with respect to the polypropylene of a secondary coating layer, and it turns out that there is a problem in a scrape. Comparison row 7 shows that there is a problem in the scrape when the amount of addition of the attacking polypropylene to the polypropylene of the secondary coating layer is too large.

It is the vertical end view which showed an example of the flame-retardant insulated wire which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Conductor, 2a ... Primary coating layer, 2b ... Secondary coating layer

Claims (6)

On the conductor, a primary coating layer and a secondary coating layer are applied from the inside, the primary coating layer is made of a polyolefin resin composition, and the secondary coating layer is 80 to 95 parts by mass of polypropylene and 20 to 5 masses of polyethylene. It is characterized by comprising a flame retardant resin composition in which 80 to 100 parts by mass of a hydrated metal compound and 30 to 50 parts by mass of a triazine flame retardant are added to 100 parts by mass of a polyolefin resin mixture composed of parts. Fire retardant insulated wire. The flame-retardant insulated wire according to claim 1, wherein the hydrated metal compound is magnesium hydroxide. The flame retardant insulated wire according to claim 1, wherein the triazine flame retardant is melamine cyanurate. 4. The flame retardant according to claim 1, wherein 5 to 30 parts by mass of the polypropylene is an attack polypropylene having a surface hardness measured by ASTM-D2240 of 60 or less. Insulated wire. The flame-retardant insulated electric wire according to claim 1, wherein the polypropylene has a melting point of 160 ° C or higher. A wire harness comprising the flame-retardant insulated electric wire according to any one of claims 1 to 5.

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