JP6738547B2 - Insulated wire and cable - Google Patents

Description

The present invention relates to insulated wires and cables.

Insulated wires and cables are provided with a coating layer (insulation layer or sheath) so as to cover the outer periphery of the conductor. As these forming materials, a halogen-free non-halogen flame-retardant resin composition containing no halogen compound is used. As the non-halogen flame-retardant resin composition, for example, a base polymer in which an ethylene-vinyl acetate copolymer (EVA) and a maleic acid-modified polyolefin are mixed with a metal hydroxide as a flame retardant is proposed. (For example, see Patent Document 1).

JP, 2014-53247, A

By the way, in addition to flame retardancy, the coating layer of insulated wires and cables used for wiring of railway cars and automobiles is also resistant to deterioration by fuel from the viewpoint of safety and durability, and has excellent fuel resistance. Is required.

In order to improve the fuel resistance, it is possible to use a highly polar polymer as the base polymer. However, when a polymer having high polarity is used, the heat resistance of the coating layer may be impaired. In addition, the non-halogen flame-retardant resin composition containing a polymer with high polarity is difficult to handle because the pellets stick to each other when pelletized, and it is difficult to form the coating layer with good productivity.

Therefore, an object of the present invention is to solve the above problems and to provide a technique for manufacturing an insulated wire and a cable having excellent fuel resistance and heat resistance with high productivity.

According to one aspect of the invention,
An insulated wire comprising a conductor and an insulating layer provided on the outer periphery of the conductor,
The insulating layer is
It contains an ethylene-vinyl acetate copolymer having a melting point of 70° C. or higher by DSC method and an acid-modified polyolefin resin, and the vinyl acetate content derived from the ethylene-vinyl acetate copolymer is 25% by mass or more and 26.5% by mass or less. Formed from a non-halogen flame-retardant resin composition containing a base polymer and a metal hydroxide,
When performing a vertical combustion test in accordance with EN60332-1-2, the distance between the lower end of the upper support material and the carbonization start point is 50 mm or more, and flame retardancy,
Provided is an insulated wire having heat resistance with a residual tensile strength of 60% or more after a heating test at 158° C. for 168 hours.

According to another aspect of the invention,
A cable comprising a conductor, an insulating layer provided on the outer periphery of the conductor, and a sheath provided on the outer periphery of the insulating layer,
The sheath is
It has an ethylene-vinyl acetate copolymer having a melting point of 70° C. or higher by DSC method and an acid-modified polyolefin resin, and the vinyl acetate content derived from the ethylene-vinyl acetate copolymer is 25% by mass or more and 26.5% by mass or less. Formed from a non-halogen flame-retardant resin composition containing a base polymer and a metal hydroxide,
When performing a vertical combustion test in accordance with EN60332-1-2, the distance between the lower end of the upper support material and the carbonization start point is 50 mm or more, and flame retardancy,
Provided is a cable having heat resistance with a tensile strength residual ratio of 60% or more after a heating test at 158° C. for 168 hours.

ADVANTAGE OF THE INVENTION According to this invention, the insulated wire and cable which are excellent in flame retardancy, fuel resistance, and heat resistance are obtained.

It is sectional drawing of the insulated wire which concerns on one Embodiment of this invention. It is sectional drawing of the cable which concerns on one Embodiment of this invention.

<One Embodiment of the Present Invention>
An embodiment of the present invention will be described below.

(1) Configuration of Insulated Electric Wire An insulated electric wire according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of an insulated wire according to an embodiment of the present invention.

As shown in FIG. 1, the insulated wire 10 includes a conductor 11 and an insulating layer 12 provided on the outer periphery of the conductor 11.

As the conductor 11, a commonly used metal wire, for example, a copper wire, a copper alloy wire, an aluminum wire, a gold wire, a silver wire, or the like can be used. Alternatively, a metal wire having an outer periphery plated with a metal such as tin or nickel may be used. Further, a collective twisted conductor in which metal wires are twisted together can be used.

The insulating layer 12 is provided so as to cover the conductor 11. The insulating layer 12 is formed of a cross-linked product obtained by cross-linking a halogen-free flame-retardant resin composition described below. The insulating layer 12 is manufactured by, for example, extruding a halogen-free flame-retardant resin composition on the outer periphery of the conductor 11 in a predetermined thickness and crosslinking the composition.

(2) Halogen-free flame-retardant resin composition forming an insulating layer The halogen-free flame-retardant resin composition (hereinafter, also simply referred to as a non-halogen material) contains a base polymer, a metal hydroxide, and an antioxidant. Is configured. Hereinafter, each component will be described.

[Base polymer]
The base polymer contains an ethylene-vinyl acetate copolymer having a melting point of 70° C. or higher according to the DSC method and an acid-modified polyolefin resin.

(Ethylene-vinyl acetate copolymer)
The ethylene-vinyl acetate copolymer (hereinafter, also simply referred to as EVA) contains vinyl acetate (VA) having a polar group and has a predetermined polarity. EVA having polarity is excellent in flame resistance and fuel resistance. In the present embodiment, among such EVA, EVA having a melting point (Tm) measured by a differential scanning calorimetry (DSC method) of 70° C. or higher is used. Generally, EVA deteriorates due to elimination of acetic acid by heating and decomposition of the main chain, but EVA having a Tm of 70° C. or higher has a relatively small amount of VA and less elimination of acetic acid by heating. It does not easily deteriorate and has excellent heat resistance. Furthermore, since the tackiness of the non-halogen material can be reduced, it is possible to prevent the pellets from sticking to each other when pelletized (so-called blocking). On the other hand, EVA having a Tm of less than 70° C. is excellent in flame retardancy but inferior in heat resistance, and also increases the tackiness of the non-halogen material and causes blocking. The upper limit of Tm of EVA is not particularly limited, but as described later, from the viewpoint of easily adjusting the amount of VA in the base polymer to a range of 25% by mass or more and 50% by mass or less, preferably 100° C. or less, more preferably It is preferably 95°C or lower, more preferably 90°C or lower. EVA having a melting point of 70° C. or higher and 100° C. or lower has a VA amount of 6% by mass or more and 28% by mass or less.

The base polymer may contain at least one EVA having a Tm of 70° C. or higher, and may contain two or more EVAs having different Tm. Preferably, three types of EVA having a Tm of 70° C. or higher are contained, and more preferably, two types of EVA having a Tm of 70° C. or higher are contained. In the present embodiment, EVA having Tm of less than 70° C. may be included in addition to EVA having Tm of 70° C. or more. EVA having a Tm of less than 70° C. is a polymer having a larger amount of VA and lower crystallinity than EVA having a Tm of 70° C. or more. EVA having a Tm of less than 70° C. has, for example, a VA amount of 28% by mass or more. By using such an EVA together, the VA amount in the base polymer is adjusted to a range of 25% by mass or more and 50% by mass or less. It will be easier.

The EVA preferably has a melt mass flow rate (MFR) of 6 g/10 min or more. More preferably, the MFR of EVA having a Tm of 70° C. or higher is 6 g/10 min or higher. By using such EVA, it is possible to enhance the fluidity when the non-halogen material is melted and improve the productivity when the non-halogen material is extruded to form the insulating layer 12. When two or more types of EVA are used, at least one of them has an MFR of 6 g/10 min or more.

(Acid-modified polyolefin resin)
The acid-modified polyolefin resin is, for example, a polyolefin modified with an unsaturated carboxylic acid or its derivative. The acid-modified polyolefin resin can improve the adhesion between the base polymer and the metal hydroxide, suppress the penetration and diffusion of fuel oil into the interface, and also suppress the interface destruction at low temperature. That is, the acid-modified polyolefin resin improves the fuel resistance and cold resistance of the halogen-free material.

Examples of the polyolefin material of the acid-modified polyolefin resin include ultra-low density polyethylene, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer. , Ethylene-octene-1 copolymer and the like. In addition, examples of the acid that modifies the polyolefin include maleic acid, maleic anhydride, and fumaric acid. These acid-modified polyolefin resins may be used alone or in combination of two or more.

The acid-modified polyolefin resin preferably has a glass transition point (Tg) of −55° C. or lower. The acid-modified polyolefin resin having a Tg of −55° C. or lower can lower the Tg of the base polymer and prevent the insulating layer 12 from cracking when exposed to a low temperature environment. That is, the cold resistance of the insulating layer 12 can be improved.

(VA amount in the base polymer)
The base polymer contains EVA and an acid-modified polyolefin resin, and contains vinyl acetate (VA) derived from EVA in a predetermined ratio. The amount of VA in the base polymer is calculated by the following formula (1) when there are 1, 2, 3... k... N types of EVA.

(In the formula (1), X _k is the VA amount (mass %) of EVA of a certain type k, Y _k is a ratio of the EVA of a certain type k to the whole base polymer, and k is a natural number, respectively. Show.)

The amount of VA in the base polymer is 25% by mass or more and 50% by mass or less. It is preferably 25% by mass or more and 46% by mass or less, more preferably 25% by mass or more and 35% by mass or less. When the amount of VA in the base polymer is less than 25% by mass, the polarity of the base polymer becomes excessively small, and thus the flame retardancy and fuel resistance of the insulating layer 12 become insufficient. On the other hand, if the amount of VA exceeds 50% by mass, the amount of acetic acid desorbed from EVA increases when the base polymer is heated to a high temperature. The heat resistance of will become low. In addition, the non-halogen material is likely to block, and the insulating layer 12 cannot be formed with high productivity.

The amount of VA in the base polymer can be appropriately changed depending on the ratio (mass ratio) of EVA having VA and acid-modified polyolefin resin. The ratio may be such that the amount of VA in the base polymer is 25% by mass or more and 50% by mass or less. Preferably, the ratio of EVA to acid modified polyolefin resin is 70:30 to 99:1. That is, the content of EVA is 70% by mass or more and 99% by mass or less and the content of the acid-modified polyolefin resin is 1% by mass or more and 30% by mass or less with respect to the base polymer.

The base polymer preferably contains only EVA and an acid-modified polyolefin resin, but may contain a polymer other than EVA and an acid-modified polyolefin resin as long as the characteristics of the non-halogen material are not impaired. In this case, the total content of EVA and the acid-modified polyolefin resin is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 100% by mass with respect to the base polymer.

The non-halogen material contains a metal hydroxide as a flame retardant. The metal hydroxide decomposes and dehydrates when the non-halogen material is heated and burned, and the released moisture lowers the temperature of the non-halogen material to suppress the combustion. Examples of the metal hydroxide that can be used include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, and metal hydroxides in which nickel forms a solid solution. These non-halogen flame retardants may be used alone or in combination of two or more. The endothermic amount of calcium hydroxide is 1000 J/g, whereas the endothermic amount of magnesium hydroxide and aluminum hydroxide is as high as 1500 J/g or more and 1600 J/g or less, so at least 1 of magnesium hydroxide and aluminum hydroxide It is preferred to use seeds.

The metal hydroxide is a silane coupling agent, a titanate coupling agent, a fatty acid such as stearic acid, a stearic acid salt, or the like because it is easy to control the mechanical properties (balance between tensile strength and elongation) of the insulating layer 12. Surface treatment with a fatty acid salt or a fatty acid metal such as calcium stearate is preferred.

The content of the metal hydroxide is preferably 100 parts by mass or more and 250 parts by mass or less with respect to 100 parts by mass of the base polymer. If the content is less than 100 parts by mass, the flame retardancy of the insulating layer 12 may decrease. If the content exceeds 250 parts by mass, the mechanical properties of the insulating layer 12 will deteriorate and the elongation will decrease.

Other additives may be contained in the non-halogen material, if necessary. For example, when the insulating layer 12 is crosslinked, a crosslinking agent or a crosslinking aid may be contained. Examples of the cross-linking method include an irradiation cross-linking method of irradiating the insulating layer 12 with an electron beam or radiation to cross-link it, and a chemical cross-linking method of heating the insulating layer 12 to cross-link it. In the case of the irradiation crosslinking method, it is advisable to add a crosslinking aid to the non-halogen material. As the crosslinking aid, for example, trimethylolpropane triacrylate (TMPT), triallyl isocyanurate (TAIC: registered trademark) or the like can be used. In the case of the chemical cross-linking method, it is preferable that the non-halogen material contains a cross-linking agent. As the cross-linking agent, for example, an organic peroxide such as 1,3-bis(2-t-butylperoxyisopropyl)benzene or dicumyl peroxide (DCP) can be used.

In addition to the cross-linking agent, the non-halogen material contains a flame retardant aid, an antioxidant, a lubricant, a softener, a plasticizer, an inorganic filler, a compatibilizer, a stabilizer, carbon black, a colorant and the like. Good. These can be contained in a range that does not impair the characteristics of the non-halogen material.

The non-halogen material can be obtained by mixing the above EVA, the acid-modified polyolefin, the metal hydroxide, and other additives as necessary, and kneading while heating. The kneading conditions and the order of addition of each component are not particularly limited. The kneading can be performed using a mixing roll, a Banbury mixer, a single-screw or twin-screw extruder, or the like.

<Effects according to the embodiment of the present invention>
According to this embodiment, one or more of the following effects are exhibited.

(A) In the insulated wire 10 of the present embodiment, EVA having an melting point (Tm) of 70° C. or higher and acid-modified polyolefin resin has a vinyl acetate amount (VA amount) derived from EVA of 25% by mass or more and 50% by mass or less. The insulating layer 12 is formed using a non-halogen material containing a base polymer blended as described above. Since such an insulating layer 12 has a predetermined high polarity, it has excellent flame retardancy and fuel resistance. In addition, the insulating layer 12 is composed of EVA having a Tm of 70° C. or higher and a relatively small amount of VA so that the amount of VA in the base polymer is 50% by mass or less. Is also excellent.

(B) In this embodiment, the polarity of the base polymer is prevented from becoming excessively large by setting the amount of VA in the base polymer to 50% by mass or less. Moreover, EVA having Tm of 70° C. or higher and high crystallinity is used. Thereby, the tackiness of the non-halogen material can be suppressed, and when the non-halogen material is pelletized, the pellets can be prevented from sticking to each other and blocking. By using such a halogen-free material, the insulating layer 12 can be formed with high productivity.

(C) In the present embodiment, the content of the metal hydroxide is 100 parts by mass or more and 250 parts by mass or less with respect to 100 parts by mass of the base polymer. Thereby, the flame retardancy can be improved without impairing the mechanical strength (tensile strength and elongation) of the insulating layer 12.

(D) In this embodiment, an acid-modified polyolefin resin having a glass transition point of −55° C. or lower is used. Thereby, the glass transition point of the base polymer can be lowered and the cold resistance of the insulating layer 12 can be improved.

(E) In this embodiment, the ratio of the predetermined EVA to the acid-modified polyolefin resin is 70:30 to 99:1. Thereby, the fuel resistance and the cold resistance can be improved in a well-balanced manner without deteriorating the mechanical characteristics of the insulating layer 12.

(F) In this embodiment, EVA having a Tm of 70° C. or higher has a melt flow rate of 6 g/10 min or higher. This can improve the fluidity when the non-halogen material is melted, so that the insulating layer 12 can be formed with high productivity.

(G) In this embodiment, since the insulating layer 12 does not contain halogen, halogen gas is not generated during combustion.

<Other Embodiments of the Present Invention>
Although one embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment and can be appropriately modified without departing from the scope of the invention.

In the above embodiment, the case where the insulating layer 12 has a single-layer structure has been described, but the insulating layer 12 may have a multi-layer structure including a plurality of resin layers. When the insulating layer 12 has a multi-layer structure, the non-halogen material described above may be used for each layer of the multi-layer structure, the non-halogen material described above may be used for the outermost layer, and a polyolefin resin or rubber material may be used for the layers other than the outermost layer. A multilayer structure may be used. As the polyolefin resin, for example, low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, maleic anhydride polyolefin, etc. are used. be able to. These polyolefin resins may be used alone or in combination of two or more.
Examples of the rubber material include ethylene-propylene copolymer rubber (EPR), ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), hydrogenated NBR (HNBR), acrylic rubber. , Ethylene-acrylic acid ester copolymer rubber, ethylene-octene copolymer rubber (EOR), ethylene-vinyl acetate copolymer rubber, ethylene-butene-1 copolymer rubber (EBR), butadiene-styrene copolymer rubber (SBR), isobutylene-isoprene copolymer rubber (IIR), block copolymer rubber having a polystyrene block, urethane rubber, phosphazene rubber and the like can be used. These rubber materials may be used alone or in combination of two or more.

Moreover, the insulated wire 10 may be provided with a separator, a braid, or the like, if necessary.

Further, in the above-described embodiment, the case of the insulated wire 10 using the non-halogen material for the insulating layer 12 has been described, but, for example, as shown in FIG. 2, the sheath 22 of the cable 20 may use the non-halogen material. is there. FIG. 2 is a cross-sectional view of the cable 20 according to the embodiment of the present invention.

A cable 20 according to an embodiment of the present invention includes a two-core stranded wire 21 obtained by twisting two insulated electric wires 10 shown in FIG. 1 and a sheath 22 provided on the outer periphery of the two-core stranded wire 21. It is configured. The sheath 22 is formed of a cross-linked product obtained by cross-linking the above-mentioned non-halogen material. In the cable 20 of the present embodiment, the sheath 22 is made of the above-mentioned non-halogen material, so that it has excellent flame retardancy, fuel resistance, and heat resistance.

The sheath 22 may have a single layer structure as shown in FIG. 2 or a laminated structure in which a plurality of resin layers are laminated. In the case of a laminated structure, the non-halogen material described above may be used for each layer of the multi-layer structure, the non-halogen material described above may be used for the outermost layer, and the polyolefin resin or rubber material may be used for the layers other than the outermost layer. May be

In addition, in FIG. 2, the case where two insulated electric wires 10 are twisted has been described, but one or three or more twisted wires may be twisted. Further, although the case where the insulated wire 10 of FIG. 1 constitutes the cable has been described, the cable 20 may be constituted by using an insulated wire provided with an insulating layer made of a general-purpose non-halogen material.

Next, the present invention will be described more specifically with reference to examples. The present invention is not limited to the examples below.

(1) Raw materials The raw materials used for the non-halogen material are as follows.

The following were used as EVA.
・EVA (Tm: 89° C., MFR: 15 g/10 min, VA amount: 14% by mass): "Eva Flex EV550" manufactured by Mitsui DuPont Polychemical Co., Ltd.
・EVA (Tm: 72° C., MFR: 6 g/10 min, VA amount: 28% by mass): “Eva Flex EV260” manufactured by Mitsui DuPont Polychemical Co., Ltd.
EVA (Tm: less than 70° C., MFR: 100 g/10 min, VA amount: 46% by mass): "Eva Flex 45X" manufactured by Mitsui DuPont Polychemical Co., Ltd.
EVA (Tm: less than 70° C., MFR: 2.5 g/10 min, VA amount: 46% by mass): “Eva Flex EV45LX” manufactured by Mitsui DuPont Polychemical Co., Ltd.
EVA (Tm: 62° C., MFR: 1 g/10 min, VA amount: 33% by mass): “Eva Flex EV170” manufactured by Mitsui DuPont Polychemical Co., Ltd.
EVA (Tm: less than 70° C., MFR: 5.1 g/10 min, VA amount: 80% by mass): “Levapren 800” manufactured by LANXESS Co., Ltd.

The following were used as the acid-modified polyolefin.
Acid-modified polyolefin (Tm: 70° C., Tg: −50° C. or lower): “Tuffuma-MA8510” manufactured by Mitsui Chemicals, Inc.

The following were used as the metal hydroxide.
-Magnesium hydroxide (silane treatment): "MAGNIFIN H10A" manufactured by Albemarle Corporation
Magnesium hydroxide (fatty acid treatment): "MAGNIFIN H10C" manufactured by Albemarle Corporation
・Aluminum hydroxide (silane treatment): "BF013STV" manufactured by Nippon Light Metal Co., Ltd.
・Aluminum hydroxide (fatty acid treatment): Showa Denko KK "Hijilite H42S"

The following were used as other additives.
-Crosslinking aid (trimethylolpropane trimethacrylate): "TMPT" manufactured by Shin Nakamura Chemical Co., Ltd.

(2) by blending various ingredients as shown in Preparation Tables 1 and 2 of non-halogen material, the starting temperature 40 ° C. by a pressure kneader, was kneaded with exit temperature of 200 ° C., pelleted, examples, Reference Example It was prepared non-halogen material of Comparative example 1-3 Contact and. In addition, in Table 1 and Table 2, the numerical value is shown by the mass part unit.

(3) Fabrication of Cable First, a twisted conductor was prepared by twisting 19 conductors having a diameter of 0.18 mm. Then, using a 65 mm extruder, ethylene propylene rubber was extrusion-coated on the outer periphery of the twisted conductor at 150° C., and an insulated wire was obtained by irradiating with 10 Mrad electron beam and crosslinking. Two insulated wires thus obtained were prepared and twisted together to prepare a two-core twisted wire. Then, using a 90 mm extruder, the non-halogen material prepared in the above (2) was extrusion-coated at 120° C. on the outer circumference of the two-core stranded wire so that the outer diameter was 4.4 mm, and then 4 Mrad. A cable was obtained by irradiating with an electron beam and crosslinking.

(4) Evaluation method The obtained cable was evaluated by the method shown below.

(Storability at room temperature)
In order to evaluate the room temperature storability, the non-halogen material was stored at room temperature and evaluated for blocking. Specifically, 20 kg of the pelletized non-halogen material was packed in a 420 mm×820 mm paper bag, and two paper bags were stacked in a constant temperature bath at 40° C. and stored for 240 hours. Then, the pellet was opened in a vat and it was confirmed whether the pellet was blocked. If blocking did not occur, it was evaluated as "pass", and if blocking occurred, it was evaluated as "fail".

(Flame retardancy test)
A vertical burning test was performed on the produced cable in accordance with EN60332-1-2. After the flame was extinguished, if the distance between the lower end of the upper support material and the carbonization start point was 50 mm or more, the result was “Good”, and if it was less than 50 mm, the result was “Fail”.

(Fuel resistance test)
The sheath was peeled off from the produced cable, and the obtained sheath was subjected to a fuel resistance test according to EN60811-1-3 to evaluate the fuel resistance. Specifically, the sheath was immersed in the fuel resistance test oil IRM903, heated in a constant temperature bath at 70° C. for 168 hours, and allowed to stand at room temperature for 16 hours, and then a tensile test was performed. Then, with respect to the sheath, the residual tensile strength ratio of the tensile strength after oil immersion to the initial tensile strength (before oil immersion) and the residual elongation ratio of the elongation ratio after oil immersion to the initial elongation ratio were measured. .. If the residual tensile strength was 70% or more, it was rated "O", and if it was less than 70%, it was rated "X". In addition, when the residual elongation rate was 60% or more, it was evaluated as “◯”, and when it was less than 60%, it was evaluated as “x”.

(Heat resistance test)
The sheath was stripped off from the produced cable, and the obtained sheath was subjected to a heat resistance test according to GB/T2951, 12-2008 to evaluate the heat resistance. Specifically, the sample was heated in a constant temperature bath at 158° C. for 168 hours, left at room temperature for 24 hours, and then subjected to a tensile test. Then, the residual elongation of the sheath after heating was measured with respect to the initial (before heating) elongation of the sheath. If the residual elongation rate was 60% or more, the result was “Good”, and if it was less than 60%, the result was “Fail”.

(Comprehensive evaluation)
In the comprehensive evaluation, if all the evaluations are ◯, the result is “good”, and if there is at least one evaluation result, the result is “fail”.

(5) Evaluation Results As shown in Table 1, Examples and Reference Example, all of the evaluation is ○, the overall evaluation was ○.

In Comparative Example 1, the amount of VA in the base polymer was less than 25% by mass, so it was confirmed that sufficient flame retardancy could not be obtained.
In Comparative Example 2, EVA having a Tm of 70° C. or higher was not used, and the VA amount of the base polymer exceeded 50 mass %, so that it was confirmed that the heat resistance was low. In addition, it was confirmed that the non-halogen material was blocked and the room temperature storability was poor. As a result, a step of crushing the blocked pellets is required, and the sheath cannot be formed with high productivity.
In Comparative Example 3, the Tm of EVA contained in the base polymer was all lower than 70° C., so that it was confirmed that the room temperature storability was poor and the fuel resistance was low.

<Preferred embodiment of the present invention>
Hereinafter, the preferred embodiments of the present invention will be additionally described.

[Appendix 1]
According to one aspect of the invention,
An insulated wire comprising a conductor and an insulating layer provided on the outer periphery of the conductor,
The insulating layer is
A base containing an ethylene-vinyl acetate copolymer having a melting point of 70° C. or higher by DSC method and an acid-modified polyolefin resin, and having a vinyl acetate content derived from the ethylene-vinyl acetate copolymer of 25% by mass or more and 50% by mass or less. Formed from a non-halogen flame-retardant resin composition containing a polymer and a metal hydroxide,
When performing a vertical combustion test in accordance with EN60332-1-2, the distance between the lower end of the upper support material and the carbonization start point is 50 mm or more, and flame retardancy,
Provided is an insulated wire having heat resistance with a residual tensile strength of 60% or more after a heating test at 158° C. for 168 hours.

[Appendix 2]
The insulated wire according to Appendix 1, preferably,
At least one of the ethylene-vinyl acetate copolymers contained in the base polymer has a melt flow rate of 6 g/10 min or more.

[Appendix 3]
The insulated wire according to appendix 1 or 2, preferably,
The metal hydroxide is magnesium hydroxide or aluminum hydroxide.

[Appendix 4]
The insulated wire according to any one of appendices 1 to 3, preferably:
The metal hydroxide is silane-treated or fatty acid-treated.

[Appendix 5]
According to another aspect of the invention,
A cable comprising a conductor, an insulating layer provided on the outer periphery of the conductor, and a sheath provided on the outer periphery of the insulating layer,
The sheath is
A base containing an ethylene-vinyl acetate copolymer having a melting point of 70° C. or higher by a DSC method and an acid-modified polyolefin resin, and the vinyl acetate content derived from the ethylene-vinyl acetate copolymer being 25% by mass or more and 50% by mass or less Formed from a non-halogen flame-retardant resin composition containing a polymer and a metal hydroxide,
When performing a vertical combustion test according to EN60332-1-2, the distance between the lower end of the upper support material and the carbonization start point is 50 mm or more, and the flame retardancy,
Provided is a cable having heat resistance with a tensile strength residual ratio of 60% or more after a heating test at 158° C. for 168 hours.

[Appendix 6]
The cable of appendix 5, preferably
At least one of the ethylene-vinyl acetate copolymers contained in the base polymer has a melt flow rate of 6 g/10 min or more.

[Appendix 7]
The cable according to appendix 5 or 6, preferably
The metal hydroxide is magnesium hydroxide or aluminum hydroxide.

[Appendix 8]
The cable according to any one of appendices 5 to 7, preferably,
The metal hydroxide is silane-treated or fatty acid-treated.

10 Insulated Electric Wire 11 Conductor 12 Insulation Layer 20 Cable 21 Two-Core Stranded Wire 22 Sheath

Claims (4)

An insulated wire comprising a conductor and an insulating layer provided on the outer periphery of the conductor,
The insulating layer is
An ethylene-vinyl acetate copolymer having a melting point of 70° C. or more and 72° C. or less by the DSC method, an ethylene-vinyl acetate copolymer having a melting point of less than 70° C. by the DSC method, and an acid-modified polyolefin resin; Is formed from a non-halogen flame-retardant resin composition containing a base polymer having a vinyl acetate content of 25% by mass or more and 26.5% by mass or less derived from coalescence, and a metal hydroxide,
The metal hydroxide comprises a silane-treated metal hydroxide and a fatty acid-treated metal hydroxide,
When performing a vertical combustion test in accordance with EN60332-1-2, the distance between the lower end of the upper support material and the carbonization start point is 50 mm or more, and flame retardancy,
An insulated wire having a heat resistance such that the residual tensile strength after the heat test at 158° C. for 168 hours is 60% or more when a heat resistance test according to GB/T2951, 12-2008 is performed . The insulated wire according to claim 1, wherein at least one of the ethylene-vinyl acetate copolymer contained in the base polymer has a melt flow rate of 6 g/10 min or more. A cable comprising a conductor, an insulating layer provided on the outer periphery of the conductor, and a sheath provided on the outer periphery of the insulating layer,
The sheath is
Ethylene having a melting point below 70 ° C. or higher 72 ° C. by DSC method - vinyl acetate copolymer, a melting point by DSC method is lower than 70 ° C. Ethylene - comprises vinyl acetate copolymer and an acid-modified polyolefin resins, et styrene - vinyl acetate copolymer It is formed from a non-halogen flame-retardant resin composition containing a base polymer having a vinyl acetate content of 25% by mass or more and 26.5% by mass or less derived from a polymer, and a metal hydroxide,
The metal hydroxide comprises a silane-treated metal hydroxide and a fatty acid-treated metal hydroxide,
When performing a vertical combustion test in accordance with EN60332-1-2, the distance between the lower end of the upper support material and the carbonization start point is 50 mm or more, and flame retardancy,
A cable having heat resistance such that the residual tensile strength after the heat test at 158° C. for 168 hours is 60% or more when a heat resistance test according to GB/T2951, 12-2008 is performed . The cable according to claim 3, wherein at least one of the ethylene-vinyl acetate copolymer contained in the base polymer has a melt flow rate of 6 g/10 min or more.