JP2002324440A - Environment-resistant halogen-free flame-retardant electric wire/cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an environment-resistant halogen-free flame-retardant electric wire/cable excellent in durability against corrosive gases such as ozone, NOx, and SOx. SOLUTION: The cable has a plurality of electric wires of copper conductors 1 each covered with an insulator 2 in a medium material 6, all covered with a sheath surface layer 10, a sheath inner layer 11 containing a halogen-free, flame-retardant agent, and a sheath innermost layer 12. The sheath surface layer 10 contains magnesium hydroxide 0-25 pts.wt. per 100 pts.wt. of resin, the magnesium hydroxide being the cause of surface stickiness or the like under a special environment where corrosive gases such as ozone, NOx, and SOx exist.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an environmentally resistant non-halogen flame-retardant electric wire / cable, and particularly to ozone and NO.
The present invention relates to environment-resistant non-halogen flame-retardant electric wires and cables having excellent durability against corrosive gases such as x and SOx.

[0002]

2. Description of the Related Art In recent years, non-halogen flame-retardant electric wires and cables which do not use polyvinyl chloride or halogen-based flame retardants and have a small environmental load have rapidly spread as so-called eco-electric wires and cables. In these non-halogen flame-retardant electric wires and cables, a resin composition in which a large amount of a non-halogen flame retardant such as magnesium hydroxide is mixed with polyolefin is used as an insulator of the electric wire or a sheath of the cable. .

[0003]

However, according to the conventional halogen-free flame-retardant electric wires and cables, since the sheath is made flame-retardant with magnesium hydroxide, extremely high concentrations of ozone, NOx, SOx and the like in a humid environment are obtained. When exposed to corrosive gases, magnesium hydroxide causes stickiness on the surface and condensation at high temperatures and high humidity. In addition, when the surface is dried, a small amount of crystalline substance remains on the surface, which causes a reduction in appearance.

In a normal installation environment, atmospheric ozone, N
The above problem does not occur because the concentration of corrosive gas such as Ox and SOx is low. However, especially for wiring in a panel and high-voltage power supply, electric wires and wires wired in a closed space where electrical contacts such as a relay box exist. In a cable and an electric wire / cable for an automobile / vehicle, an environment in which the gas is locally highly concentrated is assumed, and thus the above problem is likely to occur.

Accordingly, an object of the present invention is to provide an ozone, NO
An object of the present invention is to provide an environment-resistant non-halogen flame-retardant electric wire / cable excellent in durability against corrosive gases such as x and SOx.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides an environmentally resistant non-halogen resistant resin having a coating layer such as an insulating layer and an outer cover made of a resin containing a non-halogen flame retardant such as magnesium hydroxide. In a fuel wire / cable, the coating layer has at least an inner layer and an outer layer, and the outer layer includes an environment-resistant non-halogen flame-retardant wire, characterized in that the outer layer contains the halogen-free flame retardant in a lower content than the inner layer. Provide cables.

The non-halogen flame retardant in the outer layer is made of resin 10
Magnesium hydroxide may be 25 parts by weight or less based on 0 parts by weight. Thereby, the environment-resistant non-halogen flame-retardant electric wire / cable has excellent durability even in continuous use in a special environment where corrosive gas such as ozone, NOx, SOx or the like exists in high concentration, and has extremely high reliability.

The present inventors have investigated the causes such as surface stickiness in the special environment. As a result of analysis of various materials and systematic reproduction experiments, it was found for the first time that the above-mentioned phenomenon was caused by the deterioration of magnesium hydroxide, a flame retardant mixed in halogen-free flame-retardant wires and cables. Magnesium hydroxide is used in a humid environment with ozone, NOx,
Reacts with corrosive gases such as SOx to transform into magnesium nitrate, magnesium sulfate, etc. It has been clarified that they absorb moisture in the air, causing stickiness on the surface and dew condensation under high temperature and high humidity. In addition, when this surface is dried, a small amount of crystalline substance remaining on the surface is
It was determined that the crystals were magnesium nitrate, magnesium sulfate, etc. In order to solve the above-mentioned problems, the above-described configuration has been found as a result of various studies on a technique for preventing the causative substances such as magnesium nitrate and magnesium sulfate from being generated on the cable surface.

Further, the non-halogen flame retardant in the outer layer may be aluminum hydroxide of 250 parts by weight or less based on 100 parts by weight of the resin. As a result, durability against corrosive gas and scratch resistance are excellent, and flame retardancy is improved.

The thickness s [mm] of the outer layer has a relationship of 0.02 mm ≦ s ≦ t / 2 with respect to the thickness t [mm] (0.02 mm ≦ t) of the coating layer. In addition, the outer layer may have a structure in which the endothermic curve by a differential scanning calorimeter (DSC) has at least one endothermic peak, and the total of these endothermic amounts is 3.0 J / g or more. Good. Thereby, the trauma resistance of the electric wire / cable is improved.

[0011]

FIG. 1 shows an environment-resistant non-halogen flame-retardant cable according to a first embodiment of the present invention. In this cable, a plurality of electric wires in which a copper conductor 1 is covered with an insulator 2 are arranged in an inclusion 6, and these are connected to a sheath surface layer 1
0, a sheath inner layer 11 and a sheath innermost layer 12.

The material used for the sheath surface layer 10 is as follows.
A thermoplastic resin such as an ethylene-based polymer, a polypropylene, a thermoplastic elastomer, and an engineering plastic alone, or a resin composition in which 0 to 25 parts by weight of magnesium hydroxide is mixed with 100 parts by weight of the resin is preferable. Furthermore, a resin composition in which various additives such as a halogen-free flame retardant and a filler are blended with the resin or the resin composition can also be applied.

The ethylene polymer used for the sheath surface layer 10 includes low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), linear very low-density polyethylene (VLDPE), and high-density polyethylene (HDD).
PE), ethylene-methyl methacrylate copolymer (E
MMA), ethylene-methyl acrylate copolymer (E
MA), ethylene-ethyl acrylate copolymer (EE
A), ethylene-vinyl acetate copolymer (EVA), ethylene-glycidyl methacrylate copolymer, ethylene-
Butene-1 copolymer, ethylene-butene-hexene terpolymer, ethylene-propylene-diene terpolymer (EPDH), ethylene-octene copolymer (EO)
R), polypropylene (PP), ethylene copolymerized polypropylene, ethylene-propylene copolymer (EPR),
Poly-4-methyl-pentene-1, maleic acid-grafted low-density polyethylene, hydrogenated styrene-butadiene copolymer (H-SBR), maleic acid-grafted linear low-density polyethylene, ethylene having 4 to 20 carbon atoms α-olefin copolymer, maleic acid-grafted ethylene-methyl acrylate copolymer, maleic acid-grafted ethylene-vinyl acetate copolymer, ethylene-maleic anhydride copolymer, ethylene-ethyl acrylate-maleic anhydride terpolymer Polymer, ethylene-butene-1 as a main component
Examples thereof include propylene-butene-1 terpolymer and the like, and a material obtained by blending these alone or two or more kinds.

Examples of the polypropylene used for the sheath surface layer 10 include isotactic polypropylene and syndiotactic polypropylene, and any of homopolypropylene and random polypropylene containing an ethylene copolymer component can be used. It is also possible to blend with the ethylene-based polymer.

As the thermoplastic elastomer used for the sheath surface layer 10, there are styrene-based, ester-based, urethane-based, amide-based, and olefin-based thermoplastic elastomers.

The styrene-based thermoplastic elastomer is a styrene-based block copolymer, and SBS (PS (polystyrene) -polybutadiene-PS), SIS (PS-polyisoprene-
PS), SEBS (PS-polyethylene / butylene-P
S) and the like. Also, blends of these styrenic block copolymers and PP (polypropylene) are included.

The ester-based thermoplastic elastomer is a general term for those having PBT (polybutylene terephthalate) PET (polyethylene terephthalate) as a hard segment and a soft polyester copolymer as a soft segment, and the soft segment being PTMG (polytetramethylene glycol). ) And a terephthalic acid condensate, and a polyester-ester copolymer using polycaprolactone.

The hard segment of the urethane-based thermoplastic elastomer is polyurethane, and there are polyester and polyether types depending on the type of the soft segment.
Further, the polyester type includes a caprolactone type, an adipate type, and a polycarbonate type.

The amide-based thermoplastic elastomer refers to nylon 6, 66, 11, 12 or the like as a hard segment,
It is a thermoplastic elastomer using polyether and polyester as soft segments.

The olefin-based thermoplastic elastomer is
It is a thermoplastic elastomer having a polyolefin resin as a hard segment, and there are a blend type and a copolymer type. Here, the hard segments refer to those in the range of 15% to 95% by weight of the polymer component of the composition.

As the hard segment, a crystalline polyolefin is required, and examples thereof include PP (polypropylene), HDPE (high-density polyethylene), LDPE (low-density polyethylene), and LLDPE (linear low-density polyethylene).

The soft segments include EPM (ethylene propylene copolymer), EPDM (ethylene propylene diene terpolymer), NBR (acrylonitrile-butadiene copolymer), hydrogenated NBR, and EOR (ethylene-octene copolymer). Unified), EBR (ethylene-butene-1 copolymer), LLDPE (linear low density polyethylene), VLDPE (ultra low density polyethylene), EEA
(Ethylene-ethyl acrylate copolymer), EVA
(Ethylene-vinyl acetate copolymer) and elastomers containing a styrene component. In addition, there are those obtained by partially cross-linking the soft segments with an organic peroxide or the like, and those obtained by completely cross-linking (dynamic vulcanization) the soft segments dispersed at the time of kneading.

The engineering plastics used for the sheath surface layer 10 include polyamide, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, modified polyphenylene oxide, polyetherimide, polyamideimide, polyphenylene sulfide, polyether sulfone, polyether ether ketone, polyether A relatively flexible polyamide 46, polyamide 610, polyamide 6
12, polyamide 11, polyamide 12, polybutylene terephthalate, polyphenylene oxide modified with a styrene-based block copolymer, polyetherimide,
Polyetheretherketone is preferred.

Non-halogen flame retardants used for the sheath surface layer 10 include metal hydroxides, metal oxide compounds, phosphorus compounds, silicone compounds, boric acid compounds, nitrogen compounds,
Expandable graphite, intemescent flame retardants and the like can be mentioned.

Examples of metal hydroxide-based flame retardants include magnesium hydroxide (Mg (OH) ₂ ), aluminum hydroxide (Al (OH) ₃ ), hydrotalcite, calcium aluminate hydrate, calcium hydroxide, Barium hydroxide, hard clay and the like can be mentioned. this house,
The mixing amount of magnesium hydroxide is 25 parts by weight or less based on 100 parts by weight of the resin. Examples of the magnesium hydroxide include synthetic magnesium hydroxide, natural magnesium hydroxide obtained by pulverizing natural ore, and solid solution with other elements such as Ni. From the viewpoint of mechanical properties, dispersibility, and flame retardancy, those having an average particle diameter of 4 μm or less and 10 μm or more and a coarse particle fraction of 10% or less measured by a laser particle size distribution meter are more preferable. The surface of these particles can be treated with a fatty acid, a fatty acid metal salt, a silane-based coupling agent, a titanate-based coupling agent, an acrylic resin, or a phenol resin according to a conventional method in consideration of water resistance.

Examples of the metal oxide compound include magnesium oxide, antimony oxide, and aluminum oxide.

Examples of the phosphorus compound include red phosphorus, phosphate ester, phosphonate, phosphorinene,
Examples thereof include ammonium polyphosphate. In particular, the addition of red phosphorus is highly effective in improving flame retardancy.

Examples of the silicone compound include silicone gum, silicone powder, silicone oil, silicone-grafted polyolefin, and composite rubber of polyorganosiloxane and acrylic rubber.

Examples of the boric acid compound include zinc borate, calcium borate, barium borate, barium metaborate and the like.

Examples of the nitrogen-based flame retardant include guanidine sulfamate and melamine cyanurate.

The intimescent flame retardant is a flame retardant composed of a mixture of a component that foams and a component that solidifies during combustion. Examples of the foaming component include a nitrogen-based foaming agent, and those having a high decomposition temperature (300 ° C. or higher) such as a tetrazole compound are preferable. As the solidifying component, the phosphorus-based, silicone-based, borate-based, nitrogen-based flame retardants, polyhydric alcohols such as pentaerythritol, carbon black,
Silica, zinc, zinc stannate, interlayer silicone insert clay,
Inorganic or organic pigments are exemplified.

A filler can be added to the resin used for the sheath surface layer 10. Examples of the filler include calcium carbonate, soft clay, hard clay, calcined clay, silica, zinc oxide, mica powder, molybdenum disulfide glass fiber, glass beads, graphite, and carbon black. Among them, calcium carbonate which is easy to knead into the resin and has little decrease in mechanical properties is preferable. Calcium carbonate includes synthetic calcium carbonate (light calcium carbonate) having small particles and heavy calcium carbonate obtained by mechanically pulverizing coarse limestone. Heavy calcium carbonate having good kneading processability is more preferable. In addition, the above various compounding agents,
In consideration of water resistance, it is also possible to perform a surface treatment with a fatty acid, a fatty acid metal salt, a silane coupling agent, a titanate coupling agent or an acrylic resin or a phenol resin according to a conventional method. In addition, these resin compositions may optionally contain antioxidants, lubricants, surfactants, softeners, plasticizers,
Additives such as inorganic fillers, compatibilizers, stabilizers, crosslinkers, ultraviolet absorbers, light stabilizers, colorants and the like can be added.

When the mixing amount of magnesium hydroxide to be added to the sheath surface layer 10 exceeds 25 parts by weight with respect to 100 parts by weight of the resin, the magnesium hydroxide becomes corrosive gas such as ozone, NOx and SOx in a humid environment. Since the amount of magnesium nitrate or magnesium sulfate generated by the reaction increases, the surface becomes sticky and dew forms under high temperature and high humidity.
Alternatively, the appearance may be deteriorated due to a trace amount of crystalline substance remaining on the surface after drying. More preferably, the surface layer 10 does not contain magnesium hydroxide.

The thickness s [mm] of the sheath surface layer 10 is equal to the coating thickness t [mm] of the entire sheath (10, 11, 12).
(However, 0.02mm ≦ s) for 0.02mm ≦ t
≦ t / 2, and the material of the sheath surface layer 10 has at least one endothermic peak in an endothermic curve measured by a differential scanning calorimeter (DSC), and the total of these endothermic amounts is 3.0 J / A resin composition of at least g is desirable.

FIG. 2 shows an example of the endothermic characteristic. Thereby, the cable laying property can be improved while maintaining the flame retardancy. This is because the polymer crystal of the resin composition imparts smoothness to the cable surface, which is effective in reducing the pulling tension into the conduit and reducing the damage to the cable surface during installation. . The total heat absorption is less than 3.0 J / g, and the sheath surface layer 10
When the thickness s is less than 0.02 mm, the effect of reducing the damage is not seen. Also, when s> t / 2, when the wire / cable is burned, the sheath surface layer 10 ignites and burns, and the flame retardancy of the cable is reduced.

The material constituting the inner sheath layer 11 and the innermost sheath layer 12 which are the inner sheath of the sheath surface layer 10 is a non-halogen flame-retardant material mixed with magnesium hydroxide. Specifically, it is a resin composition obtained by mixing the following ethylene hydroxide with the following magnesium hydroxide.

Examples of the magnesium hydroxide to be mixed with the sheath inner layer 11 and the sheath innermost layer 12 include synthetic magnesium hydroxide, natural magnesium hydroxide obtained by pulverizing natural ore, and solid solution with other elements such as Ni. Can be From the viewpoint of mechanical properties, dispersibility, and flame retardancy, those having an average particle diameter of 4 μm or less and 10 μm or more and a coarse particle fraction of 10% or less measured by a laser particle size distribution meter are more preferable. The surface of these particles can be treated with a fatty acid, a fatty acid metal salt, a silane-based coupling agent, a titanate-based coupling agent, an acrylic resin, or a phenol resin according to a conventional method in consideration of water resistance.

When the flame retardant added to the sheath surface layer 10 is aluminum hydroxide, the flame retardancy of electric wires and cables can be remarkably improved. At this time, the addition amount of aluminum hydroxide is desirably 250 parts by weight or less based on 100 parts by weight of the resin. When the amount exceeds 250 parts by weight, the surface trauma is reduced regardless of the amount of heat absorbed by DSC. This phenomenon is thought to be due to the fact that when an external force is applied to the surface, a large amount of the mixed aluminum hydroxide is dug up and the smoothness of the surface is lost.

FIG. 3 shows an environment-resistant non-halogen flame-retardant electric wire according to a second embodiment of the present invention. In this electric wire, a copper conductor 1 is covered with a surface layer 3, an inner layer 4, and an innermost layer 5 made of an insulator. The surface layer 3, the inner layer 4, and the innermost layer 5 are configured similarly to the sheath surface layer 10, the inner sheath layer 11, and the innermost sheath layer 12, respectively, of the first embodiment.

FIG. 4 shows an environment-resistant non-halogen flame-retardant cable according to a third embodiment of the present invention. In this cable, four pairs of twisted wires 13 composed of two core wires in which a copper conductor 1 is covered with an insulator 2 are used as a core 15, and this core 1
5 is covered with a sheath surface layer 10 and a sheath inner layer 11. Sheath surface layer 10 and sheath inner layer 1
1 has the same configuration as that of the first embodiment.

FIG. 5 shows an environment-resistant non-halogen flame-retardant cable according to a fourth embodiment of the present invention. In this cable, a tension member 17 is disposed in the center, a slot 16 and a four-core optical fiber tape 18 are disposed around the tension member 17, and the cable is covered with a sheath surface layer 10 and a sheath inner layer 11 via a holding tape 7. . The sheath surface layer 10 and the sheath inner layer 11 are configured in the same manner as in the first embodiment.

[0042]

EXAMPLES Examples 1 to 28 of the present invention and Comparative Examples 1 to
7 will be described.

Table 1 shows the materials of the resin composition of the insulator of the electric wire and the sheath of the cable. The unit is parts by weight. 76mm preheated to 150 ° C for various resin compositions
The mixture was kneaded and pelletized by a twin-screw kneader (manufactured by Kobe Steel). The pellets were press-molded to obtain various test samples. Also,
The pellet was used as a material for producing a cable.

[Table 1]

Table 2 shows the evaluation results of Examples 1 to 16 and Comparative Examples 1 to 4 of the electric wires manufactured using the materials of Table 1. The electric wire was manufactured as follows. Non-halogen resin compositions shown in Table 1 were added to 9
It extruded using the 0-mm extruder, and produced the electric wire. The structure of the insulator is as shown in Table 2. The multilayer insulator was extruded by two-layer simultaneous extrusion, and the thickness of the coating layer was changed by adjusting the discharge amount. The total insulator thickness is 2.
0 mm.

[Table 2]

Table 3 shows the evaluation results of Examples 17 to 28 and Comparative Examples 5 to 7 of the cables manufactured using the materials of Table 1. The cable was made as follows. 38mm copper stranded circular compressed conductor with crosslinked polyethylene 4.0mm
Was produced. On the core which twisted these three cores with the polypropylene interposition,
The non-halogen resin composition shown in Table 1 was extruded as a sheath using a 90 mm extruder to prepare a cable. The structure of the sheath is as shown in Table 3. The multilayer sheath was extruded by two-layer simultaneous extrusion, and the thickness of the coating layer was changed by adjusting the discharge amount. The total sheath thickness was 3.0 mm.

[Table 3]

The evaluation of the electric wires and cables was performed by the following method.

(1) Corrosion-resistant gas test The prepared electric wires and cables were put into a desiccator, and 500 p
pm NO ₂ gas, humidity 50% RH, 20 ° C
Exposure was performed for one day. After that, electric wire and cable are heated at 40 ° C.
After being left in a 90% constant temperature / humidity chamber for 1 hour, the state of the electric wire and cable surfaces was visually observed. The case where no dew was observed on the surface was evaluated as “excellent”, the case where dew was slightly observed was evaluated as “good”, and the case where much dew was observed was evaluated as “impossible”.

(2) Quantitative Analysis of Magnesium Ions In order to confirm the relationship between the surface condensation and the amount of ionic substances produced by the attack of magnesium compounds by high-concentration corrosive gas, the amount of magnesium ions on the surface was determined. did. Deposits on the surface of the sheath of a fixed area cut from the cable sheath were wiped off with gauze thoroughly washed with pure water.
The gauze from which the deposits were wiped was put in a beaker, and about 50 ml of pure water was added. After filtration with a filter, the volume was adjusted to 100 ml to obtain an analysis sample. Plasma inductive coupling (IC
P) Quantitative analysis of magnesium was performed using an emission spectrometer (Hitachi, Model P-4000).

(3) Measurement of endotherm amount 50-300 ° C. by a differential scanning calorimeter, heating rate 10 ° C.
/ Min condition. The endothermic amount of the obtained curve was calculated from the peak area.

(4) Trauma Resistance Test FIG. 6 shows the blade used in the trauma resistance test. A test in which the blade 20 was reciprocated with a load of 3N applied to the blade 20 having a tip curvature radius of 0.225 mm was performed. The number of reciprocation of the blade until the surface of the electric wire or cable looks white due to scratching (whitening), the occurrence of wrinkles, or the tearing of the outermost layer was measured, and was used as an index of trauma resistance. Those with less than one round trip were judged as "Fail".

(5) Flame Retardancy The prepared electric wires and cables were subjected to a 60 ° inclined combustion test according to JIS C3005. The flame spread time after removing the flame was measured. Of the five tests, the one with the longest flame spread time was taken as the measured value, and the fire extinguishing in less than 15 seconds was “excellent”, 15 to 60 seconds was “good”, and the fire spread more than 60 seconds was “impossible”. And

As is clear from Tables 1 to 3, Examples 1 to 5, 7 to 19, and 2 in which the surface layer does not contain magnesium hydroxide
Each of Nos. 1 to 28 has a small or no amount of magnesium ions generated on the surface, and the degree of condensation on the surface is small or no condensation is generated. I understand. On the other hand, Comparative Examples 1 to 7 containing at least 30 parts by weight of magnesium hydroxide
As a result, a large amount of magnesium ions was generated on the surfaces of electric wires and cables due to corrosive gas, which resulted in significant surface dew condensation.

A comparison between Examples 2, 7, 9 of the electric wires and Examples 17, 21, and 23 of the cables shows that when the surface layer thickness is 0.02 mm or more, the trauma resistance is improved. Was. Also, comparing Examples 2, 8, and 10 of the electric wire and Examples 17, 22, and 24 of the cable, the relationship of s ≦ t / 2 between the surface layer thickness s and the insulator or sheath thickness t is obtained. In some cases, flame retardancy was found to be improved.

Comparing the amount of heat absorbed by DSC with the resistance to trauma shows that the greater the amount of heat absorbed, the greater the number of reciprocating blades. When Examples 13 and 16 of the electric wire and Examples 25 and 28 of the cable are compared, the heat absorption is 3 [J / g].
In the above case, the number of reciprocation of the blade is greatly improved. More preferably, it is 20 [J / g] or more,
In the case of [J / g] or more, the number of reciprocation of the blade is 5
The result is 0 or more, which is the most preferable.

Embodiments 1 to 6 of electric wire and Embodiments 11 to 11 of electric wire
Comparison of No. 15 shows that Examples 11 to 15 in which aluminum hydroxide was mixed in the surface layer had a shorter flame spread time in the combustion test than Examples 1 to 6 in which it was not mixed. . The same tendency was found for the cable examples 17 to 20 and the cable examples 25 to 27. However, the amount of aluminum hydroxide admixed in the surface layer is 2
In Examples 15 and 27 which are 80 parts, the mixing amount is 2
As compared with Examples 14 and 26 in which the amount was 50 parts by weight, the target was satisfied, but the trauma resistance was poor.

[0056]

As described above, according to the environment-resistant non-halogen flame-retardant electric wire / cable of the present invention, the ozone, NOx, NOx, The durability against corrosive gas such as SOx is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of an environment-resistant non-halogen flame-retardant cable according to a first embodiment of the present invention.

FIG. 2 is a view showing an endothermic curve of the environment-resistant non-halogen flame-retardant electric wire according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of an environment-resistant non-halogen flame-retardant cable according to a second embodiment of the present invention.

FIG. 4 is a sectional view of an environment-resistant non-halogen flame-retardant cable according to a third embodiment of the present invention.

FIG. 5 is a sectional view of an environment-resistant non-halogen flame-retardant cable according to a fourth embodiment of the present invention.

FIG. 6 shows a blade used in a trauma resistance test;
(A) is the front view, (b) is the side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copper conductor 2 Insulator 3 Surface layer 4 Inner layer 5 Innermost layer 6 Inclusion 7 Tape 10 Sheath surface layer 11 Sheath inner layer 12 Sheath innermost layer 13 Twisted wire 15 Core 16 Slot 17 Tension member 18 Four-fiber optical fiber tape 20 Blade

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 3/44 H01B 3/44 GMP 7/34 B (72) Inventor Kiyoshi Watanabe Hitachi, Ibaraki, Japan 5-1-1 Takamachi F-term in Hitachi Cable, Ltd. Research Institute of Technology (reference) CM041 CN011 CN031 CP032 DA056 DE066 DE076 DE086 DE126 DE146 DH056 DJ036 DK006 EU186 EV266 EW046 EW126 FD010 FD132 FD136 GQ01 5G303 AA06 AB20 BA11 CA09 CB01 CB02 CB17 CB15 CA02 CB28 CB30 CB28 CB30 CC02 CB30 CB28 DA23 5G315 CA03 CB02 CB06 CC08 CD02 CD13 CD14 CD17

Claims (4)

[Claims] 1. An environment-resistant non-halogen flame-retardant wire or cable in which a coating layer such as an insulating layer and a jacket is formed of a resin containing a non-halogen flame retardant such as magnesium hydroxide, wherein the coating layer comprises at least an inner layer and an outer layer. Wherein the outer layer contains a lower content of the halogen-free flame retardant than the inner layer. 2. The environment-resistant non-halogen flame-retardant electric wire / cable according to claim 1, wherein the non-halogen flame retardant in the outer layer is 25 parts by weight or less of magnesium hydroxide with respect to 100 parts by weight of the resin. 3. The environment-resistant non-halogen flame-retardant electric wire / cable according to claim 1, wherein said non-halogen flame retardant in said outer layer is aluminum hydroxide of not more than 250 parts by weight per 100 parts by weight of resin. 4. The outer layer has a thickness s [mm] of 0.02 mm ≦ s ≦ t / 2 with respect to a thickness t [mm] (0.02 mm ≦ t) of the coating layer. And the outer layer has a heat absorption curve by a differential scanning calorimeter (DSC) having at least one endothermic peak, and the total of these heat absorption amounts is a resin composition having a total of 3.0 J / g or more. The environment-resistant non-halogen flame-retardant electric wire / cable according to claim 1, characterized in that: