JP2015072743A - Wire and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire and a cable provided with a coating layer composed of a non-halogen resin composition, which are excellent in fire retardancy and good in insulation properties when immersed in water.SOLUTION: A wire has a plurality of insulation layers, and the material used in the outermost layer of the insulation layer is a non-halogen resin composition which contains a polymer consisting of a polyolefin resin and an amorphous particulate silica of a specific gravity of 2.0±0.3 g/cmand a specific surface area of 15 to 50 m/g, and has an oxygen index of 30 or greater. The material used in an inner layer of the insulation layer is a resin composition comprising 100 pts. mass of a base polymer and the added amorphous particulate silica of 10 pts. mass or less.

Description

  The present invention relates to an electric wire and a cable provided with a coating layer made of a flame-retardant non-halogen resin composition.

  Conventionally, a resin composition obtained by adding a metal hydroxide such as magnesium hydroxide or aluminum hydroxide to a polyolefin resin has been used as a flame retardant non-halogen resin composition used for electric wires, cables and the like.

  Since these non-halogen resin compositions do not contain halogen compounds, toxic gases such as hydrogen chloride and toxic substances such as dioxin are not generated during combustion. It can be prevented, and it does not matter if it is incinerated at the time of disposal.

  However, the flame retardant effect due to the addition of metal hydroxide is small and the target flame retardant is often not obtained, so when high flame retardant enough to pass the vertical combustion test etc. is required, It is necessary to increase the flame retardant effect in combination with other flame retardants.

  On the other hand, a flame retardant resin composition to which silica (colloidal silica) is added in order to increase the shell strength after combustion is known (see Patent Document 1). In addition, a resin compound containing fumed silica composed of very fine particles in order to suppress dioxin and smoke generation is known (see Patent Document 2). These silicas have an active OH group (hydroxyl group) on the surface, and the shape of the particles is not spherical. For example, Patent Document 1 describes that addition of more than 10% by weight increases the melt viscosity of the material and makes the moldability very poor.

In addition, an engineering plastic containing microsilica (granular amorphous SiO ₂ ) as a flame retardant additive is known (see Patent Document 3).

Japanese Patent Laid-Open No. 7-196877 JP 2003-64234 A JP 2008-519090 A

  However, an insulating material to which amorphous silica is added has an extremely low insulation resistance in a water-immersed state, so that it is difficult to use it under conditions where the electric wire / cable is submerged.

  Then, this invention is an electric wire and cable provided with the coating layer which consists of a non-halogen resin composition, Comprising: It aims at providing the electric wire and cable which are excellent in the flame retardance, and have the insulation property at the time of water immersion. .

  In order to achieve the above object, according to the present invention, the following electric wires and cables are provided.

[1] Having a plurality of insulating layers, as a material of the outermost layer of the insulating layers, a polymer made of a polyolefin resin, a specific gravity of 2.0 ± 0.3 g / cm ³ , and a specific surface area of 15 to 50 m ² / a non-halogen resin composition containing an amorphous fine particle silica of g and having an oxygen index of 30 or more. As an inner layer material of the insulating layer, the amorphous material is used with respect to 100 parts by mass of a base polymer. An electric wire characterized by using a resin composition in which the amount of fine particulate silica added is 10 parts by mass or less.
[2] The non-halogen resin composition contains 10 to 250 parts by mass of the amorphous fine particle silica and 0 to 200 parts by mass of a metal hydroxide with respect to 100 parts by mass of the polymer. The electric wire according to [1], wherein the total content of the fine particle silica and the metal hydroxide is 200 to 250 parts by mass.
[3] The non-halogen resin composition is characterized in that an ethylene-vinyl acetate copolymer is used as the polyolefin resin, and the vinyl acetate content (VA amount) in the polymer is 20 to 45% by mass. The electric wire according to [1] or [2].
[4] The resin composition as the material of the inner layer contains 10 parts by mass or less of the amorphous fine particle silica and 50 to 200 parts by mass of the metal hydroxide with respect to 100 parts by mass of the polymer made of polyolefin resin. The electric wire according to any one of [1] to [3], wherein:
[5] Any one of [1] to [4], wherein the outermost layer and the inner layer have a thickness of 0.08 mm or more, and the entire insulating layer has a thickness of 0.18 mm or more. The electric wire according to one.
[6] A cable comprising the electric wire according to any one of [1] to [5].
[7] As a sheath material which is the outermost layer, a polymer made of polyolefin resin and amorphous fine particle silica having a specific gravity of 2.0 ± 0.3 g / cm ³ and a specific surface area of 15 to 50 m ² / g are included. In addition, a non-halogen resin composition having an oxygen index of 30 or more is used, and the amount of the amorphous fine-particle silica added is 10 parts by mass or less with respect to 100 parts by mass of the base polymer as a material for the insulating layer covering the conductor. A cable characterized in that a resin composition is used.

  ADVANTAGE OF THE INVENTION According to this invention, it is an electric wire and cable provided with the coating layer which consists of a non-halogen resin composition, Comprising: While being excellent in a flame retardance, the insulation property at the time of water immersion is provided.

It is sectional drawing which shows one Embodiment of the electric wire of this invention.

  Hereinafter, an embodiment of the electric wire and cable of the present invention will be specifically described.

〔Electrical wire〕
The electric wire according to the embodiment of the present invention has a plurality of insulating layers, and as an outermost layer material, a polymer made of a polyolefin resin, a specific gravity of 2.0 ± 0.3 g / cm ³ , and a specific surface area of 15 A non-halogen resin composition containing amorphous fine particle silica of ˜50 m ² / g and having an oxygen index of 30 or more is used, and as a material of an inner layer of the plurality of insulating layers, 100 parts by mass of the base polymer On the other hand, a resin composition in which the amount of the amorphous fine particle silica is 10 parts by mass or less is used.

  For example, FIG. 1 is a cross-sectional view showing an embodiment of the electric wire of the present invention. As shown in FIG. 1, the electric wire 10 according to the present embodiment is a conductor made of a general-purpose material such as tin-plated copper. 1, an insulator (inner layer) 2 formed on the outer periphery of the conductor 1, and an insulator (outer layer) 3 formed on the outer periphery of the insulator (inner layer) 2.

  Below, the non-halogen resin composition used for the insulator 3 which is the outermost layer and the resin composition used for the insulator 2 which is the inner layer will be described in order.

<Non-halogen resin composition as outermost layer material>
The insulator 3 that is the outermost layer in the electric wire according to the embodiment of the present invention includes a polymer made of a polyolefin resin, an amorphous material having a specific gravity of 2.0 ± 0.3 g / cm ³ and a specific surface area of 15 to 50 m ² / g. And a non-halogen resin composition having an oxygen index of 30 or more.

(Polymer made of polyolefin resin)
The non-halogen resin composition used in the present embodiment contains a polymer composed of a polyolefin resin. Examples of polyolefin resins include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), linear very low density polyethylene (VLDPE), high density polyethylene (HDPE), polypropylene (PP), and ethylene-acrylic acid. Ethyl copolymer (EEA), ethylene-vinyl acetate copolymer (EVA), ethylene-styrene copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-butene-1 copolymer, ethylene-butene-hexene ternary Copolymer, ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer (EOR), ethylene copolymer polypropylene, ethylene-propylene copolymer (EPR), poly-4-methyl-pentene -1, maleic acid grafted low density polyethylene, hydrogenated steel Lene-butadiene copolymer (H-SBR), maleic acid grafted linear low density polyethylene, copolymer of ethylene and α-olefin having 4 to 20 carbon atoms, ethylene-styrene 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, ethylene based on butene-1 -Propylene-butene-1 terpolymer. Preferred are ethylene-ethyl acrylate copolymer (EEA), ethylene-vinyl acetate copolymer (EVA), and ethylene-butene-1 copolymer, and more preferred are ethylene-vinyl acetate copolymer (EVA). is there. These may be used alone or in combination of two or more. When blending, 80% by mass or more in the polyolefin resin is preferably EVA, more preferably 90% by mass or more is EVA, and more preferably 95% by mass is EVA. Also, two or more types of polyolefin resins, for example, two or more types of EVA can be blended and used.

  When an ethylene-vinyl acetate copolymer is used as the polyolefin-based resin, the vinyl acetate content (VA amount) in the polymer is preferably 20 to 45% by mass, and more preferably 28 to 33% by mass. .

  The amount of VA in the polymer is derived by the following formula (1) when there are 1, 2, 3,.

In the above formula (1), X VA amount of polymer _k (wt%), Y represents the proportion of the entire polymer of the polymer _k, and k is a natural number, respectively.

  In the present embodiment, it is preferable to use EVA having a melt mass flow rate (MFR) of 1.0 (g / 10 min) or less.

(Amorphous fine particle silica)
The non-halogen resin composition used in the present embodiment contains amorphous fine particle silica as a flame retardant. As the amorphous fine particle silica, one having a specific gravity of 2.0 ± 0.3 g / cm ³ and a specific surface area of 15 to 50 m ² / g can be used. By using the amorphous fine particle silica, the effects of the present invention can be achieved. The specific gravity of the amorphous fine particle silica is preferably 2.15 to 2.25 g / cm ³ , and the specific surface area is preferably 30 to 50 m ² / g.

The amorphous fine particle silica used in the present embodiment is obtained from a method of forming amorphous silica. Examples of the method for purifying amorphous silica include a method in which silica is reduced to a gas and oxidized in a vapor phase. The SiO ₂ component of the amorphous fine particle silica is preferably 90% or more, and more preferably 95% or more. The primary particle shape of the amorphous fine particle silica is close to a sphere, and the average particle size is about 100 to 200 nm (0.1 to 0.2 μm). Compared with the conventional fine particle silica described in the background art because of its spherical shape and few active hydroxyl groups, it hardly aggregates. As a result, even if the resin is highly filled, it is possible to impart flame retardancy equal to or higher than that of nano silica without causing deterioration of moldability due to aggregation and deterioration of properties such as elongation. On the other hand, conventionally used nano silica has a primary particle diameter of several to several tens of nm, and its shape is irregular and porous. Moreover, since there are active hydroxyl groups on the surface, they are strongly aggregated by hydrogen bonds, and it was difficult to disperse them as primary particles in the resin.

  The amorphous fine particle silica is preferably added in an amount of 10 to 250 parts by mass with respect to 100 parts by mass of the polymer made of polyolefin resin. If the amount is less than 10 parts by mass, a sufficient flame retardant effect tends not to be obtained. The addition amount of the amorphous fine particle silica is more preferably 30 to 200 parts by mass, and further preferably 50 to 150 parts by mass.

(Metal hydroxide)
The non-halogen resin composition used in the embodiment of the present invention preferably contains a metal hydroxide as a flame retardant. Examples of the metal hydroxide include magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like, but it is preferable to use magnesium hydroxide. These may be used alone or in combination of two or more. In addition, these flame retardants may be used which are surface-treated with a silane coupling agent, a titanate coupling agent, a fatty acid such as stearic acid, or a fatty acid metal salt such as calcium stearate.

  The metal hydroxide is preferably added in an amount of 200 parts by mass or less with respect to 100 parts by mass of the polymer made of polyolefin resin. The addition amount of the metal hydroxide is preferably 30 to 180 parts by mass, and more preferably 50 to 150 parts by mass.

  Moreover, it is preferable that the total content of the said amorphous fine particle silica and the said metal hydroxide is 100-250 mass parts with respect to 100 mass parts of polymers which consist of polyolefin resin. When added in an amount of more than 250 parts by mass, the elongation property tends to be lowered. More preferably, it is 150-200 mass parts.

(Other additives)
In addition to the above flame retardant, the non-halogen resin composition used in the embodiment of the present invention, if necessary, other flame retardants, antioxidants, metal deactivators, crosslinking agents, crosslinking aids, It is possible to add additives such as a lubricant, an inorganic filler, a compatibilizer, a stabilizer, carbon black, and a colorant. Furthermore, it may be crosslinked by an organic peroxide or by radiation such as an electron beam.

  Other flame retardants include zinc compounds such as zinc stannate, zinc hydroxystannate, zinc borate and zinc oxide, boric acid compounds such as calcium borate, barium borate and barium metaborate, phosphorus flame retardants, combustion An intumescent flame retardant composed of a mixture of a component that sometimes foams and a component that solidifies. These flame retardants can be used alone or in combination of two or more.

Examples of the antioxidant include phenolic antioxidants, sulfur-based antioxidants, amine-based antioxidants, and phosphorus-based antioxidants.
Examples of phenolic antioxidants include dibutylhydroxytoluene (BHT), pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris (3 , 5-Di-t-butyl-4-hydroxy-benzyl) -S-triazine-2,4,6- (1H, 3H, 5H) trione, thiodiethylenebis [3- (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate] and the like, more preferably pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate].
Examples of the sulfur-based antioxidant include didodecyl 3,3′-thiodipropionate, ditridecyl 3,3′-thiodipropionate, dioctadecyl 3,3′-thiodipropionate, 2,2-bis {[ 3- (dodecylthio) -1-oxopropoxy] methyl} propane-1,3-diylbis [3- (dodecylthio) propionate] (also known as: tetrakis [methylene-3- (dodecylthio) propionate] methane) and more Preferable is 2,2-bis {[3- (dodecylthio) -1-oxopropoxy] methyl} propane-1,3-diylbis [3- (dodecylthio) propionate].
Examples of amine antioxidants include 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, phenyl-1-naphthylene, alkylated diphenylamine, octylated diphenylamine, 4,4′-bis (α , Α-dimethylbenzyl) diphenylamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, p- (p-toluenesulfonylamido) diphenylamine, N, N′-di-2-naphthyl-p-phenyl Diamine, N, N'-Diphenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N '-(1,3-dimethylbutyl) -p-phenylenediamine, N -Phenyl-N '-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine, 1,3-benzenedicarboxylic acid bis [2- (1-oxo-2-phenoxypropyl) hydrazide, 2', 3 -Bis [[3- [3,5-di-tert-butyl-4-hydroxypheny ] Propionyl]] propionohydrazide, 1,2,4- -1H-3- (N- salicyloylamino-) triazole, dodecanedioic acid bis [N2- (2-hydroxybenzoyl) hydrazide], and the like.
Examples of phosphorus antioxidants include pentaerythritol phosphite, triphenyl phosphite, trioctadecyl phosphite, trilauryl trithiophosphite, and the like.
These antioxidants can be used alone or in combination of two or more.

  The metal deactivator has the effect of stabilizing metal ions by chelate formation and suppressing oxidative degradation. Examples of metal deactivators include N- (2H-1,2,4-triazol-5-yl) salicylamide, dodecanedioic acid bis [N2- (2-hydroxybenzoyl) hydrazide], 2 ′, 3-bis [[3- [3,5-di-tert-butyl-4-hydroxyphenyl] propionyl]] propionohydrazide and the like, more preferably 2 ′, 3-bis [[3- [3,5- Di-tert-butyl-4-hydroxyphenyl] propionyl]] propionohydrazide.

  Examples of the crosslinking agent include dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne. -3, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, butylcumyl peroxide, isopropylcumyl-t-butyl peroxide, and the like.

  As the crosslinking aid, for example, use of trimethylolpropane trimethacrylate (TMPT) or triallyl isocyanurate (TAIC) is desirable.

  Examples of the lubricant include fatty acids, fatty acid metal salts, fatty acid amides, and specific examples include zinc stearate. These can be used alone or in a blend of two or more.

  Examples of the inorganic filler include clay, talc, and silica. These can be surface-treated with a surface treatment agent such as fatty acid or silane. These inorganic fillers can be used alone or in combination of two or more.

  As carbon black, for example, carbon black for rubber (N900-N100: ASTM D 1765-01) is generally used.

  As the colorant, for example, a non-halogen color master batch can be used.

(Oxygen index)
The non-halogen resin composition used in the embodiment of the present invention has an oxygen index (OI) of 30 or more. The oxygen index is preferably 32 or more, more preferably 33 or more, and still more preferably 34 or more. Here, the oxygen index in the present invention refers to a value measured in accordance with ASTM D2863. The oxygen index indicates the minimum oxygen concentration (volume%) necessary for the material to continue burning, and a resin with a low oxygen index can burn at a low oxygen concentration and has low flame retardancy. It will be.

<Resin composition as inner layer material>
The insulator 2 as the inner layer in the electric wire according to the embodiment of the present invention is composed of a resin composition in which the amount of the amorphous fine particle silica is 10 parts by mass or less with respect to 100 parts by mass of the base polymer. . The base polymer can be used without particular limitation as long as the effects of the present invention are exhibited, but a halogen-free material is preferably used, and the above-described polyolefin resin is particularly preferably used. If the amount of the amorphous fine particle silica added is more than 10 parts by mass, the required electrical characteristics cannot be obtained. In addition, in the case of 10 parts by mass or less, a sufficient effect cannot be obtained only by the insulator (inner layer) 2, but sufficient flame retardancy is exhibited by using it in combination with the insulator (outer layer) 3. The addition of amorphous fine particle silica is also effective in improving wire stripping properties. The addition amount of the amorphous fine particle silica is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less.

  The resin composition constituting the insulator (inner layer) 2 further contains 50 to 200 parts by mass of the metal hydroxide described above with respect to 100 parts by mass of the base polymer (for example, a polymer made of the polyolefin resin described above). It is preferable that it is a thing, It is more preferable to contain 50-150 mass parts, It is further more preferable to contain 50-100 mass parts.

  In this embodiment mode, the insulator can have a structure of three or more layers. As a specific example in the case of a structure having three or more layers, the non-halogen resin composition is used for the outermost layer insulator, and the insulator (inner layer) 2 is formed on any one or more of the inner layers other than the outermost layer. The structure using the used resin composition is mentioned. In the case where a resin composition other than the resin composition used for the insulator (inner layer) 2 is used for any of the inner layers, it can be used without particular limitation as long as it has an insulating property as long as the effects of the present invention are exhibited. The non-halogen resin composition may be used for the insulator of the intermediate layer. Furthermore, you may give a separator, a braiding, etc. as needed.

  The thicknesses of the insulator (inner layer) 2 and the outermost insulator (outer layer) 3 are preferably 0.08 mm or more, and more preferably 0.10 mm or more. The total thickness of these insulating layers is preferably 0.18 mm or more, and more preferably 0.25 mm or more.

〔cable〕
The cable which concerns on embodiment of this invention has the electric wire which concerns on the said embodiment of this invention, It is characterized by the above-mentioned. The non-halogen resin composition is preferably used as a material for the sheath that is the outermost layer of the cable.

  Further, in the cable according to another embodiment of the present invention, the non-halogen resin composition is used as a material for a sheath that is an outermost layer, and the material for an insulating layer that covers a conductor is described above with respect to 100 parts by mass of the base polymer. A resin composition having an addition amount of the amorphous fine particle silica of 10 parts by mass or less is used.

  In the present embodiment, the sheath may be composed of a single layer or a multilayer structure. Specific examples of the multilayer structure include a structure obtained by extrusion coating the non-halogen resin composition on the outermost layer and a polyolefin resin on the outermost layer. Examples of the polyolefin resin include low density polyethylene, EVA, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, and maleic anhydride polyolefin. Or 2 or more types can be mixed and used. Furthermore, you may give a separator, a braiding, etc. as needed.

  Since the resin composition used as the material of the insulating layer covering the conductor is the same as the resin composition constituting the insulator (inner layer) 2 of the electric wire 10 described above, the description thereof is omitted. The insulating layer covering the conductor may be a single layer or a plurality of layers. In the case of a plurality of layers, the resin composition may be used in any one or more layers.

[Effect of the embodiment of the present invention]
According to the embodiment of the present invention, it is possible to obtain an electric wire and a cable that can achieve both excellent flame retardancy and insulation during water immersion. According to a preferred embodiment, it is possible to obtain an electric wire and a cable having a volume resistivity of 10 ¹³ Ω · cm or more when immersed.

[Production of electric wires of Examples and Comparative Examples]
The electric wire which coat | covered the insulators 2 and 3 with the copper conductor 1 shown in FIG. 1 was produced as follows.
In accordance with the blending ratio shown in Table 1 and Table 2, each component of each insulator layer was blended and kneaded at a start temperature of 40 ° C. and an end temperature of 190 ° C. by a pressure kneader, and the kneaded product was pelletized. Using a 65 mm extruder, pellets produced with the insulation thicknesses shown in Tables 1 and 2 were extrusion coated onto a conductor having an outer diameter of 1.1 mm at a set temperature of 200 ° C. After extrusion coating, an electron beam was irradiated at an irradiation dose of 30 kGy to crosslink to produce an electric wire.

  The oxygen index of the resin composition used for the outer layer was measured according to ASTM D2863. The measurement results are shown in Tables 1 and 2.

  The electric wires were evaluated by the method shown below. The evaluation results are shown in Tables 1 and 2.

(1) Tensile test About the produced electric wire, the tensile test was done based on JIS C3005. Tensile strengths of less than 10 MPa were evaluated as x (failed), 10-13 MPa as ◯ (accepted), and more than ◎ (accepted with tolerance). Further, the elongation of less than 150% was evaluated as x (failed), 150 to 300% as ◯ (accepted), and more than ◎ (accepted with tolerance).

(2) Flame Retardancy Test The manufactured wire was subjected to a vertical combustion test (VW-1) in the shape of the wire in accordance with EN60332-1-2. Judgment was made with a combustion time of less than 30 seconds ◎ (passed with tolerance), less than 1 minute ○ (pass), 1 minute or more × (fail).

(3) Insulation test during water immersion (volume resistivity test)
Each material is blended according to the blending ratio shown in Table 1 and Table 2, and after kneading with an open roll having a set temperature of 150 ° C., the kneaded product is put into a 1 mm thick mold using a press molding machine, and then at 180 ° C. for 1 minute. Then, a 1 mm sheet was produced. The produced 1 mm sheet was immersed in pure water at 80 ° C. for 7 days, taken out, and then volume resistivity was measured according to JIS K 6271. 1 × 10 ¹³ Ω · cm or more ◎ (passed with tolerance) 1 × 10 ¹² Ω · cm or more ○ (pass) 1 × 10 ¹² Ω · cm less than × ( Failed).

(4) Comprehensive evaluation As a comprehensive evaluation, a case where all evaluations were "good" was evaluated as "good" (pass), and if any evaluation had x (failed), it was evaluated as x (failed).

[Materials used]
(polymer)
EVA ^{* 1} : (Product name) V-5274, Mitsui DuPont Polychemical Co., Ltd. EVA ² : (Product name) EV170, Mitsui DuPont Polychemical Co., Ltd. EEA: (Product name) Bondine LX4110, Arkema Co., ethylene-butene copolymer: (trade name) Tafmer DF-810, Mitsui Chemicals Co., Ltd., PP: (trade name) BC8A, Nippon Polyethylene (flame retardant)
Amorphous fine particle silica: (trade name) SIDISTAR T120U, manufactured by Elchem Japan, specific gravity 2.2 g / cm ³ , specific surface area 40 m ² / g
Magnesium hydroxide: (trade name) Magseeds S4, manufactured by Kamishima Chemical (antioxidant)
・ Phenol-based antioxidants: (Product name) Irganox 1010, manufactured by BASF Japan ・ Sulfur-based antioxidants: (Product name) Cynox 412S, manufactured by Sipro Kasei

  As shown in Table 1, in Examples 1 to 12, all the properties of the tensile test, the flame retardancy test, and the insulation test during water immersion were good results.

  Although the VA amount of EVA which is the polymer material of the outer layer was changed in Examples 1 and 2, the flame retardancy of Example 2 having a high VA amount of 33% was improved as compared with Example 1. This shows that the VA amount is preferably 20% or more, and more preferably 30% or more.

  In Examples 3 to 4, polyolefin resin other than EVA was used as the polymer material of the outer layer, but the characteristics were good.

  In Examples 5 to 8, the addition amount of amorphous fine particle silica and magnesium hydroxide in the outer layer was changed, but it was difficult if the amorphous fine particle silica was added in an amount of 10 parts by mass or more and the oxygen index (OI) was 30 or more. The flammability was good. Moreover, it is preferable that the total addition amount of a flame retardant is 200 mass parts or more from a flame retardance improving further that the total addition amount of a flame retardant is 200 mass parts or more.

  In Examples 9 to 11, the polymer material of the inner layer was changed, but all obtained good results.

  In Example 12, when the thickness of the outer layer was 0.08 mm, the flame retardancy was reduced as compared with Example 2 in which the thickness of the outer layer was 0.15 mm. Accordingly, the thickness of the outer layer is preferably 0.10 mm or more.

  In contrast, as shown in Table 2, Comparative Examples 1 to 3 to which amorphous fine particle silica was not added and Comparative Example 6 in which the oxygen index (OI) of the outer layer was less than 30 failed in flame retardancy. . Further, in Comparative Example 6, the insulating property during water immersion was also rejected due to the addition of 15 parts by mass of amorphous fine particle silica to the inner layer.

  What should be noted are the results of the flame retardancy test of Example 2 and Comparative Example 2. In Comparative Example 2, the total amount of flame retardant added to the outer layer was 250 parts by mass, and the flame retardant test was rejected. On the other hand, in Example 2, the total amount of flame retardant added was 180 parts by mass. It was confirmed that the total amount of flame retardant added could be reduced by adding amorphous fine particle silica.

  In Comparative Examples 4 and 5 in which 30 and 100 parts by mass of amorphous fine particle silica was added to the inner layer, the insulating property during water immersion was rejected as in Comparative Example 6.

10: Electric wire, 1: Conductor, 2: Insulator (inner layer), 3: Insulator (outer layer)

Claims (7)

It has a plurality of insulating layers, and as a material of the outermost layer among the insulating layers, a polymer made of a polyolefin resin, a specific gravity of 2.0 ± 0.3 g / cm ³ , and a specific surface area of 15 to 50 m ² / g A non-halogen resin composition containing amorphous fine particle silica and having an oxygen index of 30 or more is used, and the amorphous fine particle silica is used as an inner layer material of the insulating layer with respect to 100 parts by mass of a base polymer. The electric wire characterized by using the resin composition whose addition amount is 10 mass parts or less.   The non-halogen resin composition contains 10 to 250 parts by mass of the amorphous fine particle silica and 0 to 200 parts by mass of a metal hydroxide with respect to 100 parts by mass of the polymer, and the amorphous fine particle silica and The electric wire according to claim 1, wherein the total content of the metal hydroxide is 200 to 250 parts by mass.   The ethylene / vinyl acetate copolymer is used as the polyolefin resin in the non-halogen resin composition, and a vinyl acetate content (VA amount) in the polymer is 20 to 45% by mass. The electric wire according to claim 1 or claim 2.   The resin composition as the material of the inner layer contains 10 parts by mass or less of the amorphous fine particle silica and 50 to 200 parts by mass of a metal hydroxide with respect to 100 parts by mass of the polymer made of polyolefin resin. The electric wire according to any one of claims 1 to 3, characterized in that   5. The electric wire according to claim 1, wherein a thickness of the outermost layer and the inner layer is 0.08 mm or more, and a thickness of the entire insulating layer is 0.18 mm or more. .   A cable comprising the electric wire according to claim 1. As a material for the sheath which is the outermost layer, a polymer composed of a polyolefin resin, amorphous fine particle silica having a specific gravity of 2.0 ± 0.3 g / cm ³ and a specific surface area of 15 to 50 m ² / g, and oxygen A non-halogen resin composition having an index of 30 or more is used,
A cable comprising a resin composition in which the amount of the amorphous fine-particle silica added is 10 parts by mass or less with respect to 100 parts by mass of a base polymer as a material for an insulating layer covering a conductor.

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