JP2013194214A - Non-halogen flame-retardant resin composition, and wire and cable produced by using the same - Google Patents

Abstract

Non-halogen flame retardant resin composition having cut-through strength, abrasion resistance, and flame resistance required for pressure welding wires and tensile properties satisfying UL standards, and the flame retardant resin composition Providing electric wires and cables used as covering layers.
A non-halogen flame retardant resin composition containing 60 to 100 parts by mass of a metal hydroxide and 5 to 20 parts by mass of a nitrogen-based flame retardant with respect to 100 parts by mass of a resin component, the resin component being 100 parts by mass. While containing 50-80 parts by mass of polyolefin resin and 20-50 parts by mass of styrene elastomer in the part, 2-15 parts by mass of an epoxy group-containing ethylene copolymer is included as part of the polyolefin resin. Non-halogen flame retardant resin composition.
[Selection figure] None

Description

  The present invention relates to a halogen-free flame retardant resin composition suitably used as a coating layer for electric wires and the like, and an electric wire / cable using the resin composition.

  In the internal wiring of OA equipment and electronic equipment such as copiers and printers, a large amount of wire harnesses that supply power and send signals between printed boards and between electronic parts such as printed boards and sensors, actuators, and motors are used.

  A wire harness is an assembly of terminals such as connectors that can be inserted into and removed from a terminal by bundling a plurality of electric wires and cables. From the viewpoints of flame retardancy, electrical insulation, etc., PVC electric wires using polyvinyl chloride (PVC) as an insulating material are used for electric wires for wire harnesses. Since PVC wires are excellent in flexibility, they are easy to handle even when used as wire harnesses, and have sufficient strength, so there is no problem that the insulator breaks or wears during wiring of the wire harness. Excellent workability for attaching pressure contact connectors to be mounted on.

  However, since the PVC electric wire contains a halogen element, there is a problem that a toxic gas of hydrogen chloride is generated when the used wire harness is incinerated, or dioxin is generated depending on the incineration conditions. While the reduction of environmental load is required, PVC is not a preferable material as an insulating material.

  In recent years, halogen-free electric wires using coating materials that do not contain polyvinyl chloride resin or halogen-based flame retardants have been developed in order to meet the increasing demand for reducing the environmental burden. On the other hand, insulated wires and cables used for in-machine wiring of electronic devices are generally required to have various characteristics that conform to UL (Underwriters Laboratories Inc.) standards. The UL standard stipulates in detail various properties such as flame retardancy, heat deformability, low temperature properties, initial properties of coating materials and tensile properties after heat aging.

  In an electric wire for pressure welding or crimping, it is necessary to route a wire harness in an electronic device. Since the insulation coating of the electric wire may be damaged or broken during this operation, it may become defective, so that the insulated wire used for the wire harness is required to have high cut-through strength. Abrasion resistance is also required.

  Japanese Unexamined Patent Publication No. 2002-105255 (Patent Document 1) discloses a flame retardant resin obtained by heating and kneading a metal hydrate to a thermoplastic resin component in which an elastomer such as ethylene propylene rubber or styrene butadiene rubber is blended with polypropylene. A composition and a wiring material using the composition are disclosed. Filler acceptability can be increased by blending elastomers, and by cross-linking these elastomers, it has been studied to balance mechanical properties such as flexibility and elongation with extrudability and flame retardancy. ing. However, such materials have poor wear resistance and edge resistance (cut-through characteristics) compared with PVC, and there is a problem that flexibility is lost and the balance of characteristics is lost when trying to improve these characteristics. It was.

  In JP-A-2006-36813 (Patent Document 2) and JP-A-2007-302907 (Patent Document 3), a resin mixture mainly composed of polypropylene is obtained by dynamic crosslinking in the presence of an organic peroxide. A resin composition is disclosed. Since these materials are not crosslinked by irradiation with ionizing radiation, the strength of these materials is increased by dynamic crosslinking. However, the dynamic cross-linking material has insufficient stability during extrusion, and depending on the extrusion conditions, tensile properties such as elongation and strength may be insufficient.

  If a resin composition mainly composed of polyethylene that is crosslinked by irradiation with ionizing radiation is used, the required strength can be obtained by adjusting the degree of crosslinking. However, in order to produce flame retardant properties in a non-halogen system, it is necessary to add a large amount of a flame retardant such as a metal hydroxide to the resin composition, and the cut-through strength and wear resistance required for electric wires for pressure welding or crimping applications. Can not be satisfied. Further, since the elongation is lowered, the tensile properties defined in the UL standard cannot be satisfied.

JP 2002-105255 A JP 2006-36813 A JP 2007-302907 A

  Accordingly, the present invention provides a non-halogen flame retardant resin composition having cut-through strength, abrasion resistance, and flame resistance required for pressure welding wires, and tensile properties satisfying UL standards, and the flame retardant resin composition. It is an object to provide an electric wire / cable using an object as a covering layer.

  The present invention is a non-halogen flame retardant resin composition containing 60 to 100 parts by mass of a metal hydroxide and 5 to 20 parts by mass of a nitrogen-based flame retardant with respect to 100 parts by mass of the resin component, the resin component being 100 parts by mass. Non-halogen containing 50 to 80 parts by mass of a polyolefin resin and 20 to 50 parts by mass of a styrene elastomer in a part, and 2 to 15 parts by mass of an epoxy group-containing ethylene copolymer as part of the polyolefin resin A flame retardant resin composition (claim 1).

  A polyolefin resin and a styrene elastomer are used in combination as the resin component. Polyolefin resins are widely used as wire coatings and are not only excellent in extrusion processability but also capable of crosslinking by irradiation with ionizing radiation, contributing to both tensile properties and heat resistance. In addition, since the styrene elastomer is flexible, it can not only supplement the filler acceptability, but can further improve and stabilize the tensile properties. By combining both, the tensile properties required by the UL standard can be stably obtained. Moreover, the flame retardance which can pass a VW-1 vertical combustion test can be acquired by containing a metal hydroxide and a nitrogen-type flame retardant.

  An epoxy group-containing ethylene copolymer is used as a part of the polyolefin resin. Since the epoxy group-containing ethylene copolymer is a polyethylene resin, it is crosslinked by irradiation with ionizing radiation. Moreover, by containing 2 to 15 parts by mass of the epoxy group-containing ethylene copolymer in 100 parts by mass of the resin component, the cut-through strength is remarkably improved as compared with the case where no epoxy group-containing ethylene copolymer is contained. .

  The polyolefin resin preferably contains an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 50 parts by mass. Moreover, it is preferable to contain a high density polyethylene (Claim 3). The ethylene-vinyl acetate copolymer not only excels in acceptability of flame retardants such as magnesium hydroxide due to excellent flexibility, but also contributes to improvement in elongation. High-density polyethylene also contributes to improved cut-through strength and wear resistance. As the polyolefin-based resin, it is preferable to use an ethylene-based resin that can be cross-linked by ionizing radiation irradiation, such as the above-described two types of resins. In addition to these two types of polyolefin resins, other resins such as low density polyethylene may be used.

  As the styrene elastomer, it is preferable to use a block copolymer elastomer of styrene and a rubber component. Since the block copolymer elastomer of styrene and a rubber component is stretched and has high strength, the tensile properties of the flame retardant resin composition can be further improved.

  The nitrogen-based flame retardant is preferably melamine cyanurate having an average particle size of 5 μm or less. Melamine cyanurate has good thermal stability during mixing, and is particularly excellent in flame retardancy among nitrogen-based flame retardants. Furthermore, the dispersibility at the time of mixing improves because an average particle diameter is 5 micrometers or less. The metal hydroxide is preferably magnesium hydroxide having an average particle size of 0.1 μm or more and 3 μm or less (Claim 6). The average particle size refers to a 50% particle size (D50), which is measured by a particle size distribution measuring device (Nikkiso Co., Ltd., Nanotrac (registered trademark) particle size distribution measuring device UPA-EX150) applying the laser Doppler method. it can.

  The invention according to claim 7 is an electric wire / cable using the non-halogen flame retardant resin composition as a coating layer. According to the present invention, a non-halogen insulated electric wire / cable having cut-through strength, abrasion resistance, flame retardancy, and tensile properties satisfying UL standards can be obtained.

  The invention according to claim 8 is the above-mentioned electric wire / cable, wherein the coating layer has a thickness of 0.4 mm or less. When the thickness of the insulation coating layer is as thin as 0.4 mm or less, the difference from the electric wire according to the prior art becomes remarkable in characteristics such as cut-through strength, and an excellent effect is exhibited.

  The invention according to claim 9 is the electric wire / cable according to claim 7 or 8, wherein the coating layer is crosslinked by irradiation with ionizing radiation. Since the coating layer is crosslinked, heat resistance and tensile properties are improved.

  According to the present invention, there is provided a non-halogen flame retardant resin composition having cut-through strength, abrasion resistance, and flame retardancy and tensile properties satisfying UL standards, and an electric wire / cable using the same. Can do.

It is a schematic diagram which shows the measuring method of cut-through intensity | strength.

  First, various materials used for the non-halogen flame retardant resin composition will be described. Polyolefin resins include polyethylene (high density polyethylene, linear low density polyethylene, low density polyethylene, ultra low density polyethylene), ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid. Methyl copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-propylene rubber, ethylene acrylic rubber, An ethylene-glycidyl methacrylate copolymer, an ethylene-methacrylic acid copolymer, polypropylene (homopolymer, block polymer, random polymer), polypropylene thermoplastic elastomer, ionomer resin, and the like can be used.

  An epoxy group-containing ethylene copolymer is used as a part of the polyolefin resin. The epoxy group-containing ethylene copolymer is obtained by copolymerizing an epoxy group-containing olefin monomer such as glycidyl methacrylate and an ethylene monomer. Specifically, ethylene-glycidyl methacrylate copolymer, ethylene-propylene-glycidyl methacrylate copolymer, ethylene-butene-1-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer, And ethylene-acrylic acid-glycidyl methacrylate copolymer. The content of the epoxy group-containing ethylene-based copolymer is 2 parts by mass or more and 15 parts by mass or less, more preferably 5 parts by mass or more and 10 parts by mass or less based on the entire resin component.

  As part of the polyolefin-based resin, an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 50 parts by mass is preferable. When the vinyl acetate content is less than 20 parts by mass, flame retardancy is reduced and the UL standard cannot be satisfied. In addition, when the vinyl acetate content exceeds 50 parts by mass, flame retardancy is improved, but the cut-through strength and wear resistance are also lowered along with the decrease in tensile strength, and the required characteristics cannot be satisfied. The content of the ethylene-vinyl acetate copolymer is preferably 10 parts by mass or more and 30 parts by mass or less of the entire resin component.

It is preferable that high density polyethylene is contained as part of the polyolefin resin. The high density polyethylene is a homopolyethylene or a polyethylene copolymer, and is a polyethylene having a density of 0.942 g / cm ³ or more. In addition, it is preferable to use one having a melt flow rate (hereinafter abbreviated as “MFR”, measured at 230 ° C. × 2.16 kgf, unit g / 10 min in accordance with JIS K 7210, unit g / 10 min) serving as an index of molecular weight of 0.60 or less. A lower MFR tends to improve the wear resistance. The content of the high density polyethylene is preferably 10 parts by mass or more and 30 parts by mass or less of the entire resin component.

  Examples of styrene elastomers include styrene / ethylene butene / styrene copolymers, styrene / ethylene propylene / styrene copolymers, styrene / ethylene / ethylene propylene / styrene copolymers, and styrene / butylene / styrene copolymers. These hydrogenated polymers and partially hydrogenated polymers can be exemplified. Moreover, what introduce | transduced carboxylic acid, such as maleic anhydride, can also be blended suitably and used.

  Among these, the use of a block copolymer elastomer of styrene and a rubber component is preferable from the viewpoints of improving extrudability, improving tensile elongation, and improving impact resistance. Block copolymers include hydrogenated styrene / butylene / styrene block copolymers, triblock copolymers such as styrene / isobutylene / styrene copolymers, styrene / ethylene copolymers, styrene / ethylene propylene, etc. It is preferable that the triblock component in the styrene elastomer is contained in an amount of 50% by mass or more because the strength and hardness of the coating layer are improved.

  A styrene-based elastomer having a styrene content of 20% by mass or more can be suitably used from the viewpoint of tensile properties (strength and elongation) and flame retardancy. When the styrene content is less than 20% by mass, the hardness and extrusion processability are lowered. On the other hand, when the styrene content exceeds 60% by mass, the tensile elongation decreases, which is not preferable. Furthermore, it is preferable that MFR used as a parameter | index of molecular weight is the range of 0.8-15g / 10min. This is because if the MFR is less than 0.8 g / 10 min, the extrusion processability is lowered, and if it exceeds 15 g / 10 min, the mechanical strength is lowered.

  Examples of the nitrogen-based flame retardant include melamine resin and melamine cyanurate. Nitrogen-based flame retardants do not generate toxic gases such as hydrogen halides even when incinerated after use, and can reduce the environmental burden. When melamine cyanurate is used as a nitrogen-based flame retardant, it is preferable in terms of heat stability at the time of mixing and an effect of improving flame retardancy. Melamine cyanurate can also be used after surface treatment with a silane coupling agent or a titanate coupling agent. The average particle size of the nitrogen flame retardant is preferably 5 μm or less. Content of a nitrogen-type flame retardant shall be 5 to 20 mass parts with respect to 100 mass parts of resin components. If the amount is less than 5 parts by mass, the flame resistance of the insulated wire is insufficient, and if it exceeds 20 parts by mass, the elongation and extrusion processability are deteriorated.

  Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, calcium hydroxide and the like. Among these, from the viewpoint of extrusion processability, magnesium hydroxide having an average particle size of 0.1 μm or more and 3 μm or less is preferable. Content of a metal hydroxide shall be 60 to 100 mass parts with respect to 100 mass parts of resin components. When the amount is less than 60 parts by mass, the flame resistance of the insulated wire is insufficient, and when the amount exceeds 100 parts by mass, elongation and extrusion processability are deteriorated.

  A crosslinking aid can be further added to the non-halogen flame retardant resin composition. As the crosslinking aid, a polyfunctional monomer having a plurality of carbon-carbon double bonds in the molecule such as trimethylolpropane trimethacrylate, triallyl cyanurate, triallyl isocyanurate and the like can be preferably used. Moreover, it is preferable that a crosslinking adjuvant is a liquid at normal temperature. This is because when it is a liquid, it can be easily mixed with a polyolefin resin or a styrene elastomer. Use of trimethylolpropane trimethacrylate as a crosslinking aid is preferred because compatibility with the resin is improved.

  In the non-halogen flame retardant resin composition of the present invention, an antioxidant, an antioxidant, a processing stabilizer, a colorant, a heavy metal deactivator, a foaming agent and the like can be appropriately mixed as necessary. These materials can be prepared by mixing using a known melt mixer such as a short screw extruder, a pressure kneader, or a Banbury mixer.

  The insulated wire has a coating layer made of the flame retardant resin composition, and the coating layer is formed on the conductor directly or via another layer. For forming the insulating coating layer, a known extruder such as a melt extruder can be used. The insulating layer is preferably cross-linked by irradiating with ionizing radiation. The insulated cable has a jacket such as a shield layer on the surface of the insulated wire.

  As a conductor, a copper wire, an aluminum wire, etc. which are excellent in electroconductivity can be used. The diameter of the conductor can be appropriately selected according to the intended use, but is preferably 2 mm or less in order to enable wiring in a narrow space. In consideration of ease of handling, the thickness is preferably 0.1 mm or more. The conductor may be a single wire or may be a strand of a plurality of strands.

  The thickness of the coating layer can be appropriately selected according to the conductor diameter, but the mechanical strength can be obtained by applying the flame-retardant resin composition of the present invention even when the thickness of the coating layer is 0.4 mm or less. Will be good. In the halogen-free electric wire according to the prior art, the wear resistance and the cut-through strength are reduced when the thickness of the coating layer is 0.4 mm or less, but according to the present invention, excellent performance is achieved even when the thickness of the coating layer is 0.4 mm or less. As a result, the difference from the electric wire according to the prior art appears remarkably. Moreover, in the pressure welding electric wire, an electric wire having a coating layer thickness of 0.4 mm or less is preferably used from the viewpoint of fitting property with the connector.

  When the coating layer is crosslinked by irradiation with ionizing radiation, the mechanical strength is preferably improved. Examples of ionizing radiation sources include accelerated electron beams, gamma rays, X-rays, α rays, ultraviolet rays, and the like. Is most preferably used.

  Next, the present invention will be described in more detail based on examples. The examples are not intended to limit the scope of the invention.

[Examples 1 to 14]
(Creation of non-halogen flame retardant resin composition pellets)
Each component was mixed with the formulation shown in Table 1. Using a 300 mmφ open roll mixer, the mixture was melted and mixed at a temperature of 160 ° C. to 180 ° C., and the resulting strip-shaped resin composition was cut with a pelletizer to produce pellets.

(Production of insulated wires)
Using a single-screw extruder (30 mmφ, L / D = 24), extrusion coating is applied so that the thickness is 0.25 mm on the conductor (7 twisted tin-plated annealed copper wires, conductor diameter 0.48 mm). After that, an insulated wire was created by irradiating an electron beam with an acceleration voltage of 2 MeV by 60 kGy. The tensile properties (original and after heat aging) were evaluated using a conductor layer removed from the prepared insulated wire to make only the coating layer.

(Evaluation of coating layer: tensile properties)
A conductor was extracted from the produced electric wire, and a tensile test of the coating layer was performed. The test conditions were: tensile speed = 500 mm / min, distance between marked lines = 25 mm, temperature = 23 ° C., tensile strength and tensile elongation (breaking elongation) were measured with three samples each, and the average value was obtained. It was. Those having a tensile strength of 10.3 MPa or more and a tensile elongation of 150% or more were judged as “pass”.

(Evaluation of coating layer: secant modulus)
Using a sample similar to the above tensile test, after performing a tensile test at a tensile rate of 50 mm / min, a distance between marked lines of 25 mm, and a temperature of 23 ° C., the elongation becomes 2% from the stress-elongation curve. The elastic modulus was calculated.

(Evaluation of coating layer: heat aging resistance)
After leaving the insulated wire in a gear oven set at 136 ° C. for 168 hours (7 days), a tensile test was performed in the same manner as the evaluation of the tensile properties, and the tensile strength and tensile elongation before the heat treatment were compared. A residual rate of 70% or more with respect to the tensile strength before the heat treatment and a residual rate of 45% or more with respect to the tensile elongation were regarded as acceptable levels.

(Evaluation of insulated wires: cut-through strength)
Cut-through strength was measured using the measuring apparatus shown in FIG. A blade 4 having a 90 ° sharp edge (tip R = 0.125 mm, tip angle 90 °) is applied on the insulated wire 3 composed of the conductor 1 and the covering layer 2, and the current value flowing between the conductor and the sharp edge is determined. taking measurement. In the initial state, the conductor and the sharp edge are insulated by the covering layer 2 and no current flows. However, when the covering layer 2 is cut by the blade 4, a current flows between the conductor and the sharp edge. A load is applied to the blade 4 to measure the maximum load that the coating layer 2 can withstand without being cut. The test atmosphere is a temperature of 23 ° C. and a humidity of 50% RH. A load of 35N or more was regarded as an acceptable level.

(Evaluation of insulated wires: scrape wearability)
An insulated electric wire is fixed horizontally, a piano wire with a diameter of 1.6 mm is brought into contact, and a load of 408 g is applied from above the piano wire to reciprocate at a speed of 50 to 60 Hz. The number of times until the coating layer breaks and a current flows between the conductor and the piano wire is measured. 650 times or more was regarded as an acceptable level.

(Evaluation of insulated wires: vertical combustion test)
The VW-1 vertical combustion test described in UL standard 1581, 1080 was performed on five samples. When each sample is ignited 15 seconds 5 times, digested within 60 seconds, strong absorbent cotton in the lower part is not burned by burning fallen objects, and the kraft paper attached to the upper part of the sample does not burn or burn Was passed. Five samples were evaluated and the number of samples that passed was counted.

(Evaluation of insulated wires: horizontal combustion test)
The horizontal combustion test described in UL standards 1581 and 1100 was performed on five samples, and the number of samples that passed was counted.

[Comparative Examples 1 to 11]
An insulated wire was produced in the same manner as in Examples 1 to 14 except that a resin composition having the formulation shown in Table 2 was used, and a series of evaluations were performed.

[Comparative Example 12]
Using a single-screw extruder (30 mmφ, L / D = 24), extrusion coating was performed on a conductor (7 tin-plated annealed copper wires, conductor diameter 0.48 mm) to a thickness of 0.25 mm. Then, an insulated wire having a dynamically crosslinked polypropylene as a coating layer was prepared, and a series of evaluations were performed in the same manner as in Examples 1-14. The above results are shown in Tables 1 and 2.

(footnote)
EVA1: ethylene vinyl acetate copolymer having a vinyl acetate content of 25% by mass: Mitsui DuPont Polychemical Co., Ltd., EVAFLEX EV360
EVA2: Ethylene vinyl acetate copolymer having a vinyl acetate content of 33% by mass: Evaflex EV170, manufactured by Mitsui DuPont Polychemical Co., Ltd.
HDPE1: MFR = O, density 0.951 g / cm ³ , high-density polyethylene with a hardness of 62D: made by Prime Polymer Co., Ltd., Hi-Zex 5305E
HDPE2: MFR = 0.55, density 0.959 g / cm ³ , high density polyethylene with hardness 70D: manufactured by Nippon Polyethylene Co., Ltd., Novatec HY530
HDPE3: MFR = 0.25, density 0.961 g / cm ³ , high density polyethylene with hardness 65D: made by Prime Polymer Co., Ltd., Hi-Zex 520MB
HDPE4: MFR = 0.3, density 0.964 g / cm ³ , hardness 71D high density polyethylene: manufactured by Nippon Polyethylene Co., Ltd., Novatec HB530
E-GMA: manufactured by Sumitomo Chemical Co., Ltd., Bond First E (epoxy group-containing ethylene copolymer having a glycidyl methacrylate content of 12% by mass)
St-based elastomer 1: SEEPS having a styrene content of 30% by mass: Septon (registered trademark) 4043 manufactured by Kuraray Co., Ltd.
St elastomer 2: SEEPS-OH: Kuraray Co., Ltd. Septon (registered trademark) HG252
St elastomer 3: SEBS: Asahi Kasei Corporation, Tuftec 1041
St elastomer 4: SEBS: Asahi Kasei Corporation, Tuftec H1051
St elastomer 5: SEBS: Kuraray Co., Ltd. Septon (registered trademark) HG8104
Magnesium hydroxide: Kisuma 5SDK
Melamine cyanurate: MC6000 manufactured by Nissan Chemical Industries, Ltd.
Anti-aging agent: Irganox 1010 manufactured by Ciba Specialty Chemicals Co., Ltd.
Copper protection: ADK STAB CDA-1 manufactured by Asahi Denka Kogyo Co., Ltd.
Lubricant: Stearic acid crosslinking aid: Trimethylolpropane trimethacrylate: TD1500S manufactured by DIC Corporation

  Each of the insulated wires of Examples 1 to 14 has a cut-through strength of 35 N or more, a scrape wear number of 650 times or more, and high strength. The original tensile properties (elongation, strength) and the tensile properties after heat aging (elongation, residual ratio of strength) are acceptable levels, and the flame retardancy is also satisfied.

  The non-halogen flame retardant resin composition used for the insulated wires of Comparative Examples 1 to 6 does not contain an epoxy group-containing ethylene copolymer. Original tensile properties (elongation, strength), tensile properties after heat aging (elongation, residual ratio of strength), and flame retardancy are acceptable levels, but the cut-through strength is low. From this result, it can be seen that the cut-through strength is improved when an appropriate amount of the epoxy group-containing ethylene copolymer is contained in the resin composition. Moreover, there is a scrape abrasion resistance which is not an acceptable level (Comparative Example 3 and Comparative Example 6).

  The non-halogen flame retardant resin composition used for the insulated wires of Comparative Examples 7 to 11 contains an epoxy group-containing ethylene copolymer. Since the comparative example 7 has too much content of a styrene-type elastomer, the cut-through intensity | strength is falling. In Comparative Examples 8 to 10, the content of metal hydroxide (magnesium hydroxide) is too large, and the elongation and the residual elongation after heat aging do not reach the target characteristics. Since the comparative example 11 has too much content of a nitrogen-type flame retardant (melamine cyanurate), the elongation and the residual elongation rate after heat aging do not reach the target characteristics. In the insulated wire of Comparative Example 12, a resin composition obtained by dynamically crosslinking polypropylene is used for the coating layer. Although the target properties are almost satisfied in this evaluation, the dynamic cross-linking material has insufficient stability during extrusion, and tensile properties such as elongation and strength may be insufficient depending on the extrusion conditions.

1 conductor 2 coating layer 3 insulated wire 4 blade

Claims (9)

  A non-halogen flame retardant resin composition containing 60 to 100 parts by mass of a metal hydroxide and 5 to 20 parts by mass of a nitrogen-based flame retardant with respect to 100 parts by mass of a resin component, wherein the polyolefin is contained in 100 parts by mass of the resin component Non-halogen flame retardant containing 50-80 parts by mass of a resin and 20-50 parts by mass of a styrene elastomer and 2-15 parts by mass of an epoxy group-containing ethylene copolymer as a part of the polyolefin resin. Resin composition.   The non-halogen flame retardant resin composition according to claim 1, wherein the polyolefin-based resin contains an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 parts by mass or more and 50 parts by mass or less.   The non-halogen flame retardant resin composition according to claim 1, comprising high-density polyethylene as the polyolefin resin.   The non-halogen flame retardant resin composition according to any one of claims 1 to 3, wherein the styrene elastomer is a block copolymer elastomer of styrene and a rubber component.   The non-halogen flame retardant resin composition according to any one of claims 1 to 4, wherein the nitrogen-based flame retardant is melamine cyanurate having an average particle size of 5 µm or less.   The non-halogen flame retardant resin composition according to any one of claims 1 to 5, wherein the metal hydroxide is magnesium hydroxide having an average particle size of 0.1 µm to 3 µm.   The electric wire and cable which used the halogen-free flame-retardant resin composition of any one of Claims 1-6 as a coating layer.   The electric wire / cable according to claim 7, wherein the coating layer has a thickness of 0.4 mm or less.   The electric wire / cable according to claim 7 or 8, wherein the coating layer is crosslinked by irradiation with ionizing radiation.

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