JP6289927B2 - Flame retardant resin composition and cable - Google Patents

Description

  The present invention relates to a flame retardant resin composition and a cable.

  So-called eco-materials are widely used for cable coverings, cable sheaths, tubes, tapes, packaging materials, building materials, and the like.

  As such an ecomaterial, for example, an ethylene-vinyl acetate copolymer, an ethylene-hexene-1 copolymer, a maleic anhydride-modified ethylene-octene-1 copolymer, and a flame retardant are blended. A flammable resin composition is known (see Patent Document 1 below).

JP 2001-335665 A

  However, the composition described in Patent Document 1 has room for further improvement in terms of heat deformation resistance. For this reason, there has been a demand for a flame retardant resin composition that can ensure excellent heat distortion resistance while ensuring excellent flame retardancy and excellent mechanical properties.

  The present invention has been made in view of the above circumstances, and a flame retardant resin composition capable of ensuring excellent heat deformation resistance while ensuring excellent flame resistance and excellent mechanical properties, and It aims at providing the cable using this.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research on the types and blending ratios of the base resins used in the flame-retardant resin composition. As a result, the present inventors have made a base resin containing a specific acid-modified thermoplastic resin and a specific polypropylene resin in a specific ratio in a specific ethylene polymer to contain a flame retardant in a specific ratio. It has been found that the above-described problems can be solved by the flame retardant resin composition, and the present invention has been completed.

That is, the present invention includes an ethylene polymer (A), an acid-modified thermoplastic resin (B), a homopolypropylene resin (C), and a flame retardant (D), and the ethylene polymer (A) , An ethylene-α-olefin polymer and an ethylene-unsaturated carboxylic acid ester copolymer, wherein the acid-modified thermoplastic resin (B) comprises a maleic anhydride-modified thermoplastic resin and a maleic acid-modified thermoplastic resin. And at least one thermoplastic resin selected from the ethylene-based polymer (A), the acid-modified thermoplastic resin (B), and the homopolypropylene resin (C) in 100% by mass of the ethylene-based polymer. The content of the polymer (A) is 55 to 68% by mass, the content of the acid-modified thermoplastic resin (B) is 30 to 40% by mass, and the content of the homopolypropylene resin (C) is 2 to 5% by mass. so The flame retardant (D) is 80 to 96 parts by mass with respect to 100 parts by mass in total of the ethylene polymer (A), the acid-modified thermoplastic resin (B), and the homopolypropylene resin (C). The acid-modified thermoplastic resin (B) is a flame retardant resin composition comprising a maleic anhydride-modified ethylene-propylene copolymer .

  According to the flame retardant resin composition of the present invention, it is possible to ensure excellent heat distortion resistance while securing excellent flame retardancy and excellent mechanical properties.

  In addition, the present inventors guess as follows about the reason why the heat resistant deformation resistance is excellent in the flame retardant resin composition of the present invention.

  That is, in the flame retardant resin composition of the present invention, the homopolypropylene resin (C) higher than the melting point of the ethylene polymer (A) and the acid-modified thermoplastic resin (B) is blended at a predetermined ratio. The present inventors think that the heat deformation resistance is improved. In addition, since homopolypropylene resin (C) has high crystallinity, the dispersibility of the flame retardant (D) may be inhibited and the mechanical properties may be affected. The present inventors consider that it is possible to maintain the mechanical characteristics.

  Moreover, in the said flame-retardant resin composition, it is preferable that the said alpha-olefin unit contained in the said ethylene-alpha-olefin polymer is a hexene unit.

  In this case, the flame retardant resin composition has excellent hardness and excellent scratch resistance.

  In the flame retardant resin composition, the acid-modified thermoplastic resin (B) is preferably a maleic anhydride-modified thermoplastic resin.

  In this case, the flame retardant resin composition has further excellent heat deformation resistance.

  In the said flame-retardant resin composition, it is preferable that the said flame retardant (D) contains the flame retardant containing a metal hydroxide and a phosphorus flame retardant.

  In this case, the flame retardant resin composition has particularly excellent flame retardancy.

  Moreover, this invention is a cable which has a conductor, the insulating layer which coat | covers the said conductor, and the sheath which covers the said insulating layer, and the said sheath is comprised with the flame-retardant resin composition mentioned above.

  According to the cable of the present invention, since the sheath is composed of the above-described flame retardant resin composition, it has excellent heat distortion resistance while ensuring excellent flame resistance and excellent mechanical properties. Can be secured.

  According to the present invention, there are provided a flame retardant resin composition capable of ensuring excellent heat distortion resistance while securing excellent flame retardancy and excellent mechanical properties, and a cable using the same. The

It is a partial side view which shows one Embodiment of the cable of this invention. It is sectional drawing along the II-II line of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2.

[cable]
FIG. 1 is a partial side view showing an embodiment of a cable according to the present invention, and shows a round cable. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. As shown in FIGS. 1 and 2, the round cable 10 includes an insulated wire 4 and a sheath 3 that covers the insulated wire 4. The insulated wire 4 includes an inner conductor 1 and an insulating layer 2 that covers the inner conductor 1.

Here, the sheath 3 is composed of a flame retardant resin composition, and the flame retardant resin composition includes an ethylene polymer (A), an acid-modified thermoplastic resin (B), and a homopolypropylene resin ( C) and a flame retardant (D), and the ethylene-based polymer (A) includes an ethylene-α-olefin polymer and an ethylene-unsaturated carboxylic acid ester copolymer, and includes an acid-modified thermoplastic resin (B ) Is at least one thermoplastic resin selected from the group consisting of a maleic anhydride-modified thermoplastic resin and a maleic acid-modified thermoplastic resin, an ethylene polymer (A), an acid-modified thermoplastic resin (B), The content of ethylene polymer (A) in a total of 100% by mass with homopolypropylene resin (C) is 55 to 68% by mass, the content of acid-modified thermoplastic resin (B) is 30 to 40% by mass, Polypropylene resin (C ) Is 2 to 5% by mass, and the flame retardant (D) with respect to 100 parts by mass in total of the ethylene polymer (A), the acid-modified thermoplastic resin (B), and the homopolypropylene resin (C). There Ri 80-96 parts by der, acid-modified thermoplastic resin (B) is maleic anhydride-modified ethylene - of propylene copolymer.

  The sheath 3 composed of the flame retardant resin composition can ensure excellent heat distortion resistance while ensuring excellent flame retardancy and excellent mechanical properties.

[Cable manufacturing method]
Next, the manufacturing method of the round cable 10 mentioned above is demonstrated.

(Inner conductor)
First, the inner conductor 1 is prepared. The inner conductor 1 may be composed of only one strand, or may be configured by bundling a plurality of strands. Further, the inner conductor 1 is not particularly limited with respect to the conductor diameter, the material of the conductor, and the like, and can be appropriately determined according to the application.

(Flame retardant resin composition)
On the other hand, a flame retardant resin composition is prepared. As described above, the flame retardant resin composition includes an ethylene polymer (A), an acid-modified thermoplastic resin (B), a homopolypropylene resin (C), and a flame retardant (D). Yes.

(Ethylene polymer)
The ethylene polymer used in the flame retardant resin composition of the present invention includes an ethylene-α-olefin polymer and an ethylene-unsaturated carboxylic acid ester copolymer.

  Examples of the ethylene-α-olefin polymer include polymers of ethylene and α-olefins having 2 to 19 carbon atoms. Examples of the α-olefin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1- Examples include tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene and 1-nonadecene.

  Among these, the α-olefin is preferably at least one of 1-butene and 1-hexene. Only one type of α-olefin may be contained, or two or more types may be contained.

  In the ethylene-α-olefin polymer, the α-olefin unit is preferably a hexene unit. In this case, the flame retardant resin composition has excellent hardness and excellent scratch resistance. Examples of the ethylene-α-olefin polymer containing an ethylene unit and a hexene unit include an ethylene-1-hexene copolymer and an ethylene-1-hexene-1-octene copolymer.

  The ethylene-α-olefin polymer is preferably produced using a single site catalyst. As a single site catalyst, a metallocene catalyst etc. are mentioned, for example. The polymer produced by a method other than the method using a single site catalyst has a higher polydispersity Mw / Mn than the polymer produced by a method using a single site catalyst. For this reason, when the said polymer manufactured by methods other than the method of using a single site catalyst is used as an ethylene-type polymer, sufficient mechanical characteristics cannot be provided to a flame-retardant resin composition. Here, Mw represents a weight average molecular weight, and Mn represents a number average molecular weight.

  Examples of the ethylene-unsaturated carboxylic acid ester copolymer include a copolymer of ethylene and an α, β-unsaturated carboxylic acid ester. Examples of the α, β-unsaturated carboxylic acid ester include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate and the like, and ethyl acrylate is particularly preferable.

(Acid-modified thermoplastic resin)
The acid-modified thermoplastic resin used in the flame-retardant resin composition of the present invention is at least one thermoplastic resin selected from the group consisting of a maleic anhydride-modified thermoplastic resin and a maleic acid-modified thermoplastic resin.

  Examples of maleic anhydride-modified thermoplastic resins include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene-propylene copolymer, maleic anhydride-modified ethylene-1-butene copolymer, and maleic anhydride. Modified ethylene-1-pentene copolymer, maleic anhydride modified ethylene-1-hexene copolymer, maleic anhydride modified ethylene-1-heptene copolymer, maleic anhydride modified ethylene-1-octene copolymer, etc. Can be mentioned. These may be used alone or in combination of two or more.

  Examples of maleic acid-modified thermoplastic resins include maleic acid-modified polyethylene, maleic acid-modified polypropylene, maleic acid-modified ethylene-propylene copolymer, maleic acid-modified ethylene-1-butene copolymer, maleic acid-modified ethylene-1-pentene. Examples of the copolymer include a maleic acid-modified ethylene-1-hexene copolymer, a maleic acid-modified ethylene-1-heptene copolymer, and a maleic acid-modified ethylene-1-octene copolymer. Only one type of these may be used, or two or more types may be used.

  The acid-modified thermoplastic resin used in the flame retardant resin composition of the present invention is preferably a maleic anhydride-modified thermoplastic resin.

  In this case, the flame retardant resin composition has particularly excellent heat deformation resistance.

(Homo polypropylene resin)
The flame retardant resin composition of the present invention contains a homopolypropylene resin, that is, a propylene homopolymer. By including the homopolypropylene resin, the flame retardant resin composition has excellent heat deformation resistance.

  In the flame-retardant resin composition of the present invention, the content of the ethylene polymer in the total of 100% by mass of the ethylene polymer, the acid-modified thermoplastic resin and the homopolypropylene resin is 55 to 68% by mass, and the acid-modified The content of the thermoplastic resin is 30 to 40% by mass, and the content of the homopolypropylene resin is 2 to 5% by mass. When the content of the ethylene polymer is less than 55% by mass, the flame retardant resin composition may have sufficient mechanical properties as compared with the case where the content of the ethylene polymer is 55% by mass or more. Can not. On the other hand, when the content of the ethylene polymer exceeds 68% by mass, the flame retardant resin composition has sufficient heat deformation resistance compared to the case where the content of the ethylene polymer is 68% by mass or less. I can't. The content of the ethylene polymer is preferably 65 to 68% by mass. In this case, the hardness becomes higher and the mechanical properties are improved.

  Further, when the content of the acid-modified thermoplastic resin is less than 30% by mass, the flame-retardant resin composition has sufficient mechanical properties as compared with the case where the content of the acid-modified thermoplastic resin is 30% by mass or more. Cannot have. On the other hand, when the content of the acid-modified thermoplastic resin exceeds 40% by mass, the hardness becomes lower than when the content of the acid-modified thermoplastic resin is 40% by mass or less, the wear resistance is deteriorated and the wound resistance is deteriorated. Gets worse. Furthermore, when the content of the homopolypropylene resin is less than 2% by mass, the flame retardant resin composition has sufficient heat deformation resistance as compared with the case where the content of the homopolypropylene resin is 2% by mass or more. I can't. On the other hand, when the content of the homopolypropylene resin exceeds 5% by mass, sufficient mechanical properties cannot be obtained as compared with the case where the content of the homopolypropylene resin is 5% by mass or less.

(Flame retardants)
Examples of the flame retardant used in the flame retardant resin composition of the present invention include a flame retardant containing a metal hydroxide, a phosphorus-based flame retardant, and an intimescent flame retardant. These may be used alone or in combination of two or more.

  Examples of the metal hydroxide include magnesium hydroxide and aluminum hydroxide. These may be used alone or in combination of two or more. Of these, magnesium hydroxide is particularly preferred. The flame retardant is preferably obtained by surface-treating the metal hydroxide with a surface treatment agent such as a fatty acid-containing compound, a phosphate ester, or a silane coupling agent. In this case, the dispersibility of the flame retardant in the resin is excellent.

The flame retardant containing the metal hydroxide is preferably in the form of particles and has an average particle size of 0.5 μm or more and less than 2 μm. When the average particle size is 0.5 μm or more, workability during processing is improved as compared with the case where the average particle size is less than 0.5 μm. Further, when the average particle size is less than 2 μm, there is an advantage that the mechanical strength is improved as compared with the case where the average particle size is 2 μm or more. In the present invention, the “average particle diameter” of the particles refers to the area S of a two-dimensional image when a plurality of particles are observed with a scanning electron microscope (SEM). S is considered to be equal to the area of each circle, and from these areas the following formula:
R = 2 × (S / π) ^1/2
The average value of R calculated based on

  Examples of the phosphorus flame retardant include a red phosphorus flame retardant.

  The flame retardant preferably contains a flame retardant containing a metal hydroxide and a phosphorus flame retardant. In this case, the flame retardant resin composition is particularly excellent in flame retardancy.

  When the flame retardant contains a flame retardant containing a metal hydroxide and a phosphorus flame retardant, the mass ratio of the phosphorus flame retardant to the flame retardant containing a metal hydroxide is 0.014 to 0.017. preferable. In this case, the flame retardant resin composition has further excellent flame retardancy as compared with the case where the mass ratio of the flame retardant is out of the above range.

  The flame retardant in the flame retardant resin composition of the present invention is blended at a ratio of 80 to 96 parts by mass with respect to 100 parts by mass in total of the ethylene polymer, the acid-modified thermoplastic resin and the homopolypropylene resin. When the blending ratio of the flame retardant is less than 80 parts by mass, the flame retardant resin composition cannot ensure sufficient flame retardancy. Moreover, when the blending ratio of the flame retardant exceeds 96 parts by mass, the flame retardant resin composition cannot ensure sufficient mechanical properties. The blending ratio of the flame retardant is preferably 80 to 92 parts by mass.

  The flame retardant resin composition may further contain additives such as carbon black, an antioxidant, an ultraviolet degradation inhibitor, a processing aid, a color pigment, and a lubricant as necessary.

  The flame retardant resin composition can be obtained by kneading an ethylene polymer, an acid-modified thermoplastic resin, a flame retardant, and the like. The kneading can be performed with a kneading machine such as a Banbury mixer, a tumbler, a pressure kneader, a kneading extruder, a twin screw extruder, a mixing roll, and the like.

  Next, the inner conductor 1 is covered with the flame retardant resin composition. Specifically, the flame retardant resin composition is melt kneaded using an extruder to form a tubular extrudate. Then, the tubular extrudate is continuously coated on the inner conductor 1. Thus, the insulated wire 4 is obtained.

(sheath)
Finally, the insulated wire 4 obtained as described above is prepared, and this insulated wire 4 is covered with the sheath 3 produced using the above-mentioned flame-retardant resin composition. The sheath 3 protects the insulating layer 2 from physical or chemical damage.

  The round cable 10 is obtained as described above.

  The present invention is not limited to the above embodiment. For example, although the round cable 10 has one insulated wire 4 in the above embodiment, the cable of the present invention is not limited to the round cable, and two insulated wires 4 are provided inside the sheath 3. You may have more than this. A resin portion made of polypropylene or the like may be provided between the sheath 3 and the insulated wire 4. Furthermore, the cable of the present invention may further include an outer conductor between the sheath 3 and the insulated wire 4 like a coaxial cable.

  Moreover, in the said embodiment, although the insulating layer 2 and the sheath 3 of the insulated wire 4 are comprised with said flame-retardant resin composition, the insulating layer 2 is comprised with normal insulating resin, and only the sheath 3 is the said. The flame retardant resin composition may be used.

  Furthermore, in the above embodiment, the flame retardant resin composition of the present invention is used as a material constituting the insulating layer and the sheath of the cable. However, the flame retardant resin composition of the present invention is a tube, tape, or packaging. It can also be used for materials and building materials.

  Hereinafter, the content of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

(Examples 1-5 and Comparative Examples 1-3)
Ethylene-based polymer (A), acid-modified thermoplastic resin (B), homopolypropylene resin (C), flame retardant (D) and carbon black (E) are blended in the blending amounts shown in Table 1, and then by a Banbury mixer It knead | mixed for 15 minutes at 160 degreeC, and the flame-retardant resin composition of Examples 1-5 and Comparative Examples 1-3 was obtained. In Table 1, the unit of the blending amount of each blending component is part by mass.

  Specific examples of the ethylene polymer (A), acid-modified thermoplastic resin (B), homopolypropylene resin (C), flame retardant (D), and carbon black (E) were as follows.

(A) Ethylene polymer (A-1) Ethylene-1-hexene copolymer, manufactured using a metallocene catalyst, density 0.92 g / cm ³ (manufactured by Sumitomo Chemical Co., Ltd., trade name “Excellen GMH CB5001 ")
(A-2) Ethylene-ethyl acrylate copolymer: EEA (manufactured by Nippon Polyethylene Co., Ltd., trade name “Lex Pearl A1150”)

(B) Acid-modified thermoplastic resin Maleic anhydride-modified ethylene-propylene copolymer (manufactured by Mitsui Chemicals, trade name “Toughmer MA8510”)

(C) Homopolypropylene resin homopolypropylene (manufactured by Prime Polymer Co., Ltd., trade name “E111G”)

(D) Flame retardant (D-1) Stearic acid surface-treated magnesium hydroxide particles, average particle size 0.8 μm (Kyowa Chemical Industry, trade name “Kisuma 5A”)
(D-2) Red phosphorus flame retardant, red phosphorus content of 78% or more, average particle size of 10 μm (manufactured by Rin Chemical Industry Co., Ltd., trade name “NOVALET 120UF”)

(E) Carbon black (E-1) Carbon black, average particle size 78 nm (Asahi Carbon Co., Ltd., trade name “Carbon Asahi # 35”)
(E-2) Carbon black, average particle size 31 μm (Made by Mitsubishi Chemical Co., Ltd., trade name “Diamond Black H”)

Subsequently, the flame-retardant resin compositions of Examples 1 to 5 and Comparative Examples 1 to 3 were kneaded at 160 ° C. for 15 minutes using a Banbury mixer. Thereafter, the flame retardant resin composition is put into a single screw extruder (L / D = 20, screw shape: full flight screw, manufactured by Mars Seiki Co., Ltd.), and a tubular extrudate is extruded from the extruder. A conductor (number of strands / cross-sectional area of 2 mm ² ) was coated to a thickness of 0.7 mm. Thus, an insulated wire was obtained.

<Characteristic evaluation>
(Mechanical properties)
(1) Tensile test About the flame-retardant resin compositions of Examples 1 to 5 and Comparative Examples 1 to 3, a molded plate was prepared with an extruder in accordance with JIS-K6251, and this molded plate was punched with a punching blade. A dumbbell-shaped test piece was prepared. The size of the dumbbell-shaped test piece was 20 mm between the gauge points, the minimum width was 5 mm, the maximum width was 25 mm, and the total length was 100 mm. And about this dumbbell-shaped test piece, the tensile test was done by JISC3005 and the breaking strength and tensile elongation were measured. In the tensile test, the tensile speed was 200 mm / min. The results are shown in Table 1. In Table 1, the unit of breaking strength is MPa, and the unit of tensile elongation is%. The acceptance criteria for the tensile test were as follows.

Breaking strength of 10 MPa or more and tensile elongation of 160% or more: acceptable breaking strength of less than 10 MPa or tensile elongation of less than 160%: failure

(2) Shore D hardness 35 mm × 35 mm formed by molding the flame retardant resin compositions of Examples 1 to 5 and Comparative Examples 1 to 3
X Shore D hardness indicating surface hardness was measured with a durometer hardness meter in accordance with JIS K7215 for a square test piece having a thickness of 2 mm. Table 1 shows the measurement results at an instantaneous value with a load holding time of 0 seconds. As acceptable if Shore D hardness of 53 or higher, and failed is less than 5 3.

(Heat deformation resistance)
About the square test piece of 35mmx35mmx thickness 2mm formed by shape | molding the flame-retardant resin composition of Examples 1-5 and Comparative Examples 1-3, the heat deformation test was done and the heat deformation resistance property was evaluated. . In the heat deformation test, the test temperature was 120 ° C., the load was 19.6 N, the preheating time was 1 hour, and the test time was 1 hour. The evaluation of heat deformation resistance is obtained by measuring the thickness of the test piece before the heat deformation test (thickness before the test) and the thickness of the test piece after the heat deformation test (thickness after the test). The heating deformation rate (%) was performed.

Heat distortion rate (%) = [(Thickness before test) − (Thickness after test)] / (Thickness before test) × 100 (%)

The results are shown in Table 1. Regarding the heat deformation resistance, the case where the heat deformation rate was 25% or less was accepted, and the case where the heat deformation rate exceeded 25% was rejected.

(Flame retardance)
About the said insulated wire which coat | covered the conductor with the flame-retardant resin composition of Examples 1-5 and Comparative Examples 1-3, the vertical tray combustion test based on IEEE3833-1974 standard was done. That is, an insulated wire was cut out by 2400 mm and placed on a vertical ladder tray. A burner was installed at a position 600 mm from the bottom of the tray, and combustion was started at a flame length of about 380 mm and a flame center temperature of 815 ° C. or higher. Combustion was carried out for 20 minutes, after which the burner was extinguished and held until combustion of the insulated wire was completed. After the completion of combustion, check the combustion position (position where the cable surface is carbonized). For those that did not burn to the upper end, enter “○” in the vertical tray combustion test column of Table 1 and burn to the upper end. Entered “×”. The acceptance criteria for flame retardancy were as follows.

Vertical tray combustion test result is “O”: Pass Vertical tray combustion test result is “X”: Fail

  As shown in Table 1, the flame retardant resin compositions of Examples 1 to 5 reached the acceptance criteria for mechanical properties, heat deformation resistance, and flame retardancy. On the other hand, the flame retardant resin compositions of Comparative Examples 1 to 3 did not reach the acceptance criteria for any of mechanical properties, heat deformation resistance, and flame retardancy.

  From the above, according to the flame retardant resin composition of the present invention, it was confirmed that excellent heat distortion resistance can be ensured while ensuring excellent flame retardancy and excellent mechanical properties.

DESCRIPTION OF SYMBOLS 1 ... Internal conductor 2 ... Insulating layer 3 ... Sheath 4 ... Insulated wire 10 ... Round cable

Claims (4)

An ethylene polymer (A);
An acid-modified thermoplastic resin (B);
Homopolypropylene resin (C);
Flame retardant (D),
The ethylene polymer (A) includes an ethylene-α-olefin polymer and an ethylene-unsaturated carboxylic acid ester copolymer,
The acid-modified thermoplastic resin (B) is at least one thermoplastic resin selected from the group consisting of a maleic anhydride-modified thermoplastic resin and a maleic acid-modified thermoplastic resin,
The content of the ethylene polymer (A) in a total of 100% by mass of the ethylene polymer (A), the acid-modified thermoplastic resin (B), and the homopolypropylene resin (C) is 55 to 68 masses. %, The content of the acid-modified thermoplastic resin (B) is 30 to 40% by mass, the content of the homopolypropylene resin (C) is 2 to 5% by mass,
The flame retardant (D) is in a ratio of 80 to 96 parts by mass with respect to 100 parts by mass in total of the ethylene polymer (A), the acid-modified thermoplastic resin (B) and the homopolypropylene resin (C). Blended ,
The acid-modified thermoplastic resin (B) is a flame retardant resin composition comprising a maleic anhydride-modified ethylene-propylene copolymer .   The flame retardant resin composition according to claim 1, wherein the α-olefin unit contained in the ethylene-α-olefin polymer is a hexene unit.   The flame retardant resin composition according to claim 1 or 2, wherein the flame retardant (D) contains a flame retardant containing a metal hydroxide and a phosphorus flame retardant. Conductors,
An insulating layer covering the conductor;
A sheath covering the insulating layer;
The cable by which the said sheath is comprised with the flame-retardant resin composition as described in any one of Claims 1-3.

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