JP2021036513A - Insulated wire - Google Patents

Abstract

To provide an insulated wire including a single insulating layer and not provided with a separator, the insulated wire having mechanical characteristics, flame retardancy, insulation properties, low temperature properties, heat resistance and wire processability.SOLUTION: An insulated wire 10 has a conductor 1, and an insulating layer 2 that coats the conductor 1, where the insulating layer 2 directly coats the conductor 1. A resin composition constituting the insulating layer 2 includes a base polymer, metal hydroxide, a processing aid, and a metal chelator. The base polymer includes high-density polyethylene, maleic anhydride-modified high-density polyethylene, ethylene-acrylate-maleic anhydride ternary copolymer, maleic anhydride-modified ethylene-α-olefin copolymer, and ethylene-acrylate copolymer. The processing aid is in the form of metallic soap and/or silicone processing aid.SELECTED DRAWING: Figure 1

Description

The present invention relates to an insulated electric wire.

The insulated wire has a conductor and an insulating layer as a coating layer provided around the conductor. The insulating layer of the insulated wire is made of a material mainly made of rubber or resin. Such insulated wires have different required characteristics depending on the application. For example, insulated wires for railway vehicles, automobiles, and equipment are required to have high insulation, flame retardancy, low temperature characteristics, and dynamic cut-through resistance.

In such an insulated wire, in order to obtain high wear resistance and dynamic cut-through resistance, there is a method of providing a separator between the conductor and the insulating layer, but this not only increases the manufacturing cost but also increases the manufacturing cost. , There is a problem that wiring workability is lowered. Therefore, it is desirable to improve the mechanical properties of the insulating layer without providing a separator (separatorless).

Therefore, it is conceivable to use a polymer having high crystallinity as a base polymer constituting the insulating layer of the insulated wire. Examples of the polymer having high crystallinity include high density polyethylene (HDPE).

For the purpose of achieving both insulation and flame retardancy, for example, Patent Document 1 describes an insulated wire having an insulating layer in which a metal hydroxide is added as a flame retardant to a base polymer containing high-density polyethylene. Has been done.

Japanese Unexamined Patent Publication No. 2016-17108

However, according to the study of the present inventor, for example, in a separatorless insulated wire, when the insulating layer is a single layer, the insulating layer may be composed of the resin composition having the composition described in Patent Document 1. It was confirmed that sufficient mechanical properties, flame retardancy, insulation, low temperature characteristics, heat resistance and wire workability may not be obtained.

The present invention has been made in view of such problems, and in a separatorless insulated wire having a single-layer insulating layer, it has mechanical properties, flame retardancy, insulating properties, low temperature properties, heat resistance, and wire processability. It is an object of the present invention to provide an insulated electric wire provided with.

A brief description of typical inventions disclosed in the present application is as follows.

[1] The insulated wire has a conductor and an insulating layer coated around the conductor, the insulating layer is directly coated on the conductor, and the resin composition constituting the insulating layer is , Base polymer, metal hydroxide, processing aid, and metal chelating agent. The base polymer is high-density polyethylene, maleic anhydride-modified high-density polyethylene, ethylene-acrylic acid ester-maleic anhydride ternary copolymer, maleic anhydride-modified ethylene-α-olefin copolymer, and ethylene. -Contains with acrylic ester copolymer. The processing aids include metal soaps and / or silicone-based processing aids. The resin composition contains 5 parts by mass or more and less than 35 parts by mass of the maleic anhydride-modified high-density polyethylene in 100 parts by mass of the base polymer, and contains the ethylene-acrylic acid ester-maleic anhydride ternary copolymer. It contains 30 parts by mass or more and less than 50 parts by mass, contains 5 parts by mass or more and 20 parts by mass or less of the maleic anhydride-modified ethylene-α-olefin copolymer, and 10 parts by mass or more of the ethylene-acrylic acid ester copolymer. Contains 30 parts by mass or less. The resin composition contains 140 parts by mass or more and 200 parts by mass or less of the metal hydroxide and 1 part by mass or more and 10 parts by mass or less of the processing aid with respect to 100 parts by mass of the base polymer. The chelating agent is contained in an amount of 1 part by mass or more and 10 parts by mass or less.

[2] In the insulated wire according to [1], the processing aid contains a metal soap having a melting point of 120 ° C. or higher.

[3] In the insulated wire according to [2], the processing aid contains a metal soap having a melting point of 220 ° C. or higher.

[4] In the insulated wire according to any one of [1] to [3], the amount of acrylic acid ester of the ethylene-acrylic acid ester copolymer is 10% by mass or more and 25% by mass or less.

[5] In the insulated wire according to any one of [1] to [4], the glass transition point of the maleic anhydride-modified ethylene-α-olefin copolymer is −55 ° C. or lower.

[6] In the insulated wire according to any one of [1] to [5], the resin composition contains 150 parts by mass or more and 180 parts by mass of the metal hydroxide with respect to 100 parts by mass of the base polymer. It contains the following.

[7] In the insulated wire according to any one of [1] to [6], the metal hydroxide is magnesium hydroxide.

[8] In the insulated wire according to any one of [1] to [7], the resin composition is crosslinked.

According to the present invention, it is possible to provide an insulated wire having mechanical properties, flame retardancy, insulating properties, low temperature characteristics, heat resistance and wire workability in a separatorless insulated wire having a single-layer insulating layer. ..

It is sectional drawing which shows the structure of the insulated electric wire of one Embodiment.

(Consideration)
Before explaining the embodiment, the matters examined by the present inventors will be described.

First, as described above, in an insulated wire having a conductor and an insulating layer (single layer) coated around the conductor, high-density polyethylene is used for the purpose of achieving both insulation and flame retardancy. It was examined to use a resin composition in which (B) a metal hydroxide was added as a flame retardant to (A) a base polymer containing (A) as an insulating layer (hereinafter, referred to as an insulated wire in an example of study).

When (B) metal hydroxide is used as the flame retardant, unlike halogen-based flame retardants and phosphorus-based flame retardants, toxic gas is not generated during combustion, so adverse effects on the environment and secondary disasters can be prevented. Excellent in terms of points. On the other hand, when (B) metal hydroxide is used as the flame retardant, a larger amount is used as the base polymer than the halogen-based flame retardant and the phosphorus-based flame retardant in order to ensure sufficient flame retardancy. Need to be added. However, since (A1) high-density polyethylene has low compatibility with (B) metal hydroxide, when a large amount of (B) metal hydroxide is added to (A1) high-density polyethylene, the machine of the resin composition The characteristics will deteriorate.

In the study example, the present inventors added (A5) ethylene-acrylic acid ester copolymer to (A) base polymer in addition to (A1) high-density polyethylene, and further added (A3) ethylene-acrylic acid ester. It was examined to add a ternary copolymer of maleic anhydride and (A4) modified ethylene-α-olefin copolymer of maleic anhydride.

Since the (A5) ethylene-acrylic acid ester copolymer is a polymer having high compatibility with (B) metal hydroxide, the (A5) ethylene-acrylic acid ester copolymer is added to the (A) base polymer. By doing so, even when a large amount of (B) metal hydroxide is added, deterioration of the mechanical properties of the resin composition can be suppressed.

However, the compatibility between (A1) high-density polyethylene and (A5) ethylene-acrylic acid ester copolymer is not high. Therefore, the (A3) base polymer has a polarity between (A1) high-density polyethylene and (A5) ethylene-acrylic acid ester copolymer, and (A3) ethylene-acrylic acid ester-maleic anhydride ternary copolymer weight. By further adding the coalescence and the (A4) maleic anhydride-modified ethylene-α-olefin copolymer, the adhesion between the (A) base polymer and the (B) metal hydroxide can be enhanced. As a result, in the study example, it is possible to secure both the mechanical properties of the resin composition and the flame retardancy.

Here, the present inventors have confirmed the following three problems in the study example. The first problem in the study example is that it is difficult to achieve both mechanical properties, flame retardancy and insulating properties (electrical properties). In general, if a large amount of (B) metal hydroxide is added in order to improve the flame retardancy of the resin composition, the insulating property of the resin composition is lowered. As a method for solving this problem, for example, the insulating layer of the insulated wire is added with (B) a flame-retardant layer made of a resin composition in which a large amount of metal hydroxide is added, and (B) addition of metal hydroxide. A method of forming a two-layer structure with an insulating layer made of a small amount of resin composition can be considered. However, in this way, it is difficult to reduce the diameter of the electric wire, and the manufacturing cost also increases. Therefore, it is desired to ensure mechanical properties, flame retardancy and insulation in a single insulating layer.

The second problem in the study example is that it is difficult to achieve both wire workability and insulation, and specifically, the generation of die scum and nipple scum. When an insulating layer made of a resin composition is formed around a conductor using an extrusion covering device for electric wire manufacturing, debris is generated on the die and nipple of the extrusion covering device, and this is generated on the surface of the extruded insulating layer. It will adhere. Such die scraps and nipple scraps have a problem that not only the workability of the electric wire is deteriorated and the appearance of the insulating layer is deteriorated, but also the electric field is concentrated on these scraps and causes dielectric breakdown.

The third issue in the study example is a decrease in heat resistance. In a separatorless insulated wire, the insulating layer is directly coated on the conductor. Therefore, copper or the like contained in the conductor diffuses into the insulating layer, and thermal deterioration (heat aging) using this as a catalyst occurs, so that there is a problem that heat resistance is lowered.

In addition to these three issues, it is indispensable to ensure flexibility in a low temperature environment, that is, low temperature characteristics, in the insulated wire according to the study example.

From the above, in a separatorless insulated wire having a single layer of insulating layer, by devising the configuration, an insulated wire having mechanical properties, flame retardancy, insulation, low temperature characteristics, heat resistance and wire workability can be obtained. desired.

(Embodiment)
<Main configurations and effects of insulated wires>
Hereinafter, the insulated wire according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an insulated wire according to the present embodiment. As shown in FIG. 1, the insulated wire 10 according to the present embodiment has a conductor 1 and a single-layer insulating layer 2 coated around the conductor 1. The insulated wire 10 according to the present embodiment does not have a separator, and the insulating layer 2 is directly coated on the conductor 1.

The resin composition constituting the insulating layer 2 according to the present embodiment contains (A) a base polymer, (B) a metal hydroxide, (C) a processing aid, and (D) a metal chelating agent. I'm out.

The (A) base polymer according to the present embodiment is (A1) high-density polyethylene, (A2) anhydrous maleic acid-modified high-density polyethylene, and (A3) ethylene-acrylic acid ester-anhydrous maleic acid ternary copolymer. And (A4) a maleic anhydride-modified ethylene-α-olefin copolymer and (A5) an ethylene-acrylic acid ester copolymer.

The processing aid (C) according to the present embodiment is a metal soap and / or a silicone-based processing aid.

In the present embodiment, by adopting the above configuration, the separatorless insulated wire having a single-layer insulating layer has mechanical properties, flame retardancy, insulating properties, low temperature characteristics, heat resistance, and wire processability. Can be provided. The reason for this will be described in detail below.

As described above, in the resin composition constituting the insulating layer of the insulated wire of the study example, (A) as a base polymer, (B) highly compatible with metal hydroxide (A5) ethylene-acrylic acid ester The polymer was added. Then, as the (A) base polymer, a (A3) ethylene-acrylic acid ester-maleic anhydride ternary copolymer having high compatibility with the (A5) ethylene-acrylic acid ester copolymer was added, and (A) A3) Highly compatible with the ethylene-acrylic acid ester-maleic anhydride ternary copolymer (A4) Maleylene anhydride-modified ethylene-α-olefin copolymer was added.

However, in the insulated wire of such a study example, deterioration of insulation (electrical characteristics) and wire workability has been clarified as a problem.

Therefore, (A2) maleic anhydride-modified high-density polyethylene is further added as the (A) base polymer to the resin composition according to the present embodiment. (A2) Maleic anhydride-modified high-density polyethylene has high compatibility with (A1) high-density polyethylene, and (A3) ethylene-acrylic acid ester-maleic anhydride ternary copolymer and (A4) male anhydride. It also has high compatibility with acid-modified ethylene-α-olefin copolymers. Therefore, in the present embodiment, the adhesion between the (A) base polymer and the (B) metal hydroxide can be improved, and the insulating property of the insulated wire can be improved.

Further, since the resin composition according to the present embodiment contains (A4) maleic anhydride-modified ethylene-α-olefin copolymer as (A) base polymer, flexibility in a low temperature environment is improved. However, low temperature characteristics can be ensured in the insulated wire.

Further, a metal soap and / or a silicone-based processing aid is added as the (C) processing aid to the resin composition according to the present embodiment. These processing aids intervene between the die or nipple and the resin composition when extruding the resin composition in the extrusion coating device to enhance the lubricity. As a result, in the insulated electric wire 10 according to the present embodiment shown in FIG. 1, it is possible to prevent the generation of die scraps and nipple scraps and improve the wire workability. Further, in the insulated wire 10 according to the present embodiment, since die scraps and nipple scraps are not generated, it is possible to prevent deterioration of the insulating property due to these scraps.

Further, (D) a metal chelating agent is further added to the resin composition according to the present embodiment. As described above, the insulated wire 10 according to the present embodiment shown in FIG. 1 does not have a separator, and the insulating layer 2 is directly coated on the conductor 1. In such a separatorless insulated wire, copper and the like contained in the conductor 1 diffuse into the insulating layer 2, and thermal deterioration (heat aging) using this as a catalyst occurs, so that the heat resistance is lowered. .. In this regard, since the metal chelating agent (D) added to the resin composition according to the present embodiment captures copper and the like diffused in the insulating layer 2, it is possible to prevent a decrease in the heat resistance of the insulated wire 10. it can.

From the above, in the insulated wire 10 according to the present embodiment, the separatorless insulated wire having a single-layer insulating layer has mechanical properties, flame retardancy, insulating properties, low temperature characteristics, heat resistance, and wire processability. Can be provided.

<Conductor composition>
Hereinafter, the configuration of the conductor 1 used in the insulated electric wire 10 according to the present embodiment will be described.

As the conductor 1 shown in FIG. 1, 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. Further, as the conductor 1, a conductor having metal plating such as tin or nickel around the metal wire may be used. Further, as the conductor 1, a (aggregate) twisted conductor in which metal wires are twisted can be used. The cross-sectional area and outer diameter of the conductor 1 are not particularly limited, and can be appropriately changed according to the electrical characteristics required for the insulated wire 10. The cross-sectional area of the conductor 1 is, for example, 1 mm ² or more and 10 mm ² or less, and the outer diameter of the conductor 1 is, for example, 1.20 mm or more and 2.30 mm or less.

<Structure of insulation layer>
As described above, the insulating layer 2 of the insulated wire 10 shown in FIG. 1 is made of the resin composition according to the present embodiment, which will be described in detail below. The thickness of the insulating layer 2 is not particularly limited, but is preferably 0.15 mm or more and 2 mm or less.

<Detailed composition of resin composition>
Hereinafter, the resin composition constituting the insulating layer 2 of the insulated wire 10 according to the present embodiment will be described in detail for each raw material, including the blending amount required for the establishment of the present invention.

[High density polyethylene]
The high-density polyethylene (A1) according to the present embodiment is not particularly limited in melting point, density and molecular weight, but is preferably polyethylene having a ^{density of 0.942 g / cm 3 or more.} In the present embodiment, (A1) high-density polyethylene ensures mechanical properties, particularly dynamic cut-through resistance. In the present embodiment, if the (A2) maleic anhydride-modified high-density polyethylene described later is used alone, the viscosity of the resin composition may increase. Therefore, the (A2) maleic anhydride-modified high-density polyethylene is used. At the same time, it is necessary to contain (A1) high-density polyethylene, but the content thereof is not particularly limited. However, the (A1) high-density polyethylene is preferably contained in an amount of 5 parts by mass or more and 35 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less in 100 parts by mass of the (A) base polymer. Sufficient dynamic cut-through resistance can be obtained by setting the content of (A1) high-density polyethylene to 5 parts by mass or more, more preferably 10 parts by mass or more, out of 100 parts by mass of the (A) base polymer. By setting the content of (A1) high-density polyethylene to 35 parts by mass or less, more preferably 30 parts by mass or less in 100 parts by mass of (A) base polymer, (A1) high density in (A1) base polymer. Polyethylene and (A2) maleic anhydride-modified high-density polyethylene can be blended in a well-balanced manner, and sufficient insulating properties (electrical characteristics) can be ensured as described later.

[Maleic anhydride-modified high-density polyethylene]
(A2) Maleic anhydride-modified high-density polyethylene is a high-density polyethylene graft-copolymerized with maleic anhydride.

The (A2) maleic anhydride-modified high-density polyethylene according to the present embodiment is not particularly limited in melting point, density and molecular weight, but has a density equivalent to that of (A1) high-density polyethylene from the viewpoint of compatibility. It is preferable to have. In the present embodiment, (A2) maleic anhydride-modified high-density polyethylene, like (A1) high-density polyethylene, ensures mechanical properties, particularly dynamic cut-through resistance, and has a phase with (A1) high-density polyethylene. Insulation (electrical characteristics) is ensured because of its high solubility and compatibility with (B) metal hydroxide.

The resin composition according to the present embodiment contains (A2) maleic anhydride-modified high-density polyethylene in an amount of 5 parts by mass or more and less than 35 parts by mass in 100 parts by mass of the (A) base polymer. By setting the content of (A2) maleic anhydride-modified high-density polyethylene to 5 parts by mass or more out of 100 parts by mass of (A) base polymer, sufficient insulating properties can be obtained as an insulating layer of an insulated wire. Further, (A2) maleic anhydride-modified high-density polyethylene has high adhesion to (B) metal hydroxide, but the content thereof is less than 35 parts by mass in 100 parts by mass of (A) base polymer. The viscosity of the composition does not become too high, and when it is formed as an insulating layer, it is possible to prevent the appearance from being roughened, and it is possible to prevent a situation in which dielectric breakdown occurs from a portion where the layer thickness is thinned.

[Ethylene-acrylic acid ester-maleic anhydride ternary copolymer]
Since the (A3) ethylene-acrylic acid ester-maleic anhydride ternary copolymer according to the present embodiment has a larger amount of maleic anhydride than the maleic anhydride-modified polymer (graft copolymer of maleic anhydride). It has higher compatibility with (B) metal hydroxide than maleic anhydride-modified polymer. Therefore, in the present embodiment, the (A3) ethylene-acrylic acid ester-maleic anhydride ternary copolymer ensures mechanical properties, particularly wear resistance.

The resin composition according to the present embodiment contains (A3) ethylene-acrylic acid ester-maleic anhydride ternary copolymer in an amount of 30 parts by mass or more and less than 50 parts by mass in 100 parts by mass of the (A) base polymer. By setting the content of the (A3) ethylene-acrylic acid ester-maleic anhydride ternary copolymer to 30 parts by mass or more out of 100 parts by mass of the (A) base polymer, sufficient wear resistance as an insulating layer of the insulated wire is obtained. When the property is obtained and the amount is less than 50 parts by mass in (A) 100 parts by mass of the base polymer, sufficient elongation can be obtained as an insulating layer of the insulated wire.

(A3) Ethylene-acrylic acid ester-maleic anhydride ternary copolymer includes ethylene-methyl acrylate-maleic anhydride ternary copolymer, ethyl ethylene-ethyl acrylate-maleic anhydride ternary copolymer, and the like. Examples thereof include ethylene-butyl acrylate-maleic anhydride ternary copolymer, and one of them may be used alone or two or more of them may be used in combination. In the present embodiment, the amount of acrylic acid ester and the amount of maleic anhydride are not particularly limited, but the amount of acrylic acid ester is 5% by mass from the viewpoint of (B) enhancing the adhesion with the metal hydroxide. The amount of maleic anhydride is preferably 2.8% by mass or more and 3.6% by mass or less, preferably 30% by mass or more.

[Maleic anhydride-modified ethylene-α-olefin copolymer]
The (A4) maleic anhydride-modified ethylene-α-olefin copolymer according to the present embodiment is obtained by graft-copolymerizing maleic anhydride with an ethylene-α-olefin copolymer. The ethylene-α-olefin copolymer has excellent flexibility in a low temperature environment, and by modifying it with maleic anhydride, the compatibility with (B) metal hydroxide is improved. Therefore, in the present embodiment, the (A4) maleic anhydride-modified ethylene-α-olefin copolymer ensures mechanical properties, particularly low temperature properties.

The resin composition according to the present embodiment contains (A4) maleic anhydride-modified ethylene-α-olefin copolymer in an amount of 5 parts by mass or more and 20 parts by mass or less in 100 parts by mass of the (A) base polymer. By setting the content of the (A4) maleic anhydride-modified ethylene-α-olefin copolymer to 5 parts by mass or more out of 100 parts by mass of the (A) base polymer, sufficient low temperature characteristics can be obtained, and the (A) base can be obtained. By setting the amount to 20 parts by mass or less out of 100 parts by mass of the polymer, it is possible to obtain appropriate flexibility and sufficient dynamic cut-through resistance.

Further, in the resin composition according to the present embodiment, the glass transition point of the (A4) maleic anhydride-modified ethylene-α-olefin copolymer is preferably −55 ° C. or lower. (A4) Maleic anhydride-modified ethylene-α-olefin copolymer is a polymer having high adhesion to (B) metal hydroxide and having excellent flexibility in a low temperature environment. is there. Therefore, by setting the glass transition point of the (A4) maleic anhydride-modified ethylene-α-olefin copolymer to −55 ° C. or lower, the low temperature characteristics of the resin composition containing the same can be improved. In the present embodiment, the glass transition point of the (A4) maleic anhydride-modified ethylene-α-olefin copolymer can be measured by the differential scanning calorimetry (DSC) method. It is not limited to.

(A4) Examples of the ethylene-α-olefin copolymer which is a raw material of the maleic anhydride-modified ethylene-α-olefin copolymer include a copolymer of α-olefin having 3 or more and 12 or less carbon atoms and ethylene. Be done. Examples of the α-olefin having 3 or more and 12 or less carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methylpentene, 1-heptene, 1-octene and the like. preferable. As the (A4) maleic anhydride-modified ethylene-α-olefin copolymer exemplified here, one of them may be used alone, or two or more kinds thereof may be used in combination.

[Ethylene-acrylic acid ester copolymer]
The (A5) ethylene-acrylic acid ester copolymer according to the present embodiment has high compatibility with (B) metal hydroxide, and (A3) ethylene-acrylic acid ester-maleic anhydride ternary compound. It has high compatibility with the polymer. Therefore, (B) metal hydroxide can be dispersed in (A) base polymer. Further, the (A5) ethylene-acrylic acid ester copolymer forms a carbonized layer at the time of combustion and exhibits a flame retardant effect. From the above, in the present embodiment, the (A5) ethylene-acrylic acid ester copolymer ensures flame retardancy.

The resin composition according to the present embodiment contains (A5) ethylene-acrylic acid ester copolymer in an amount of 10 parts by mass or more and 30 parts by mass or less in 100 parts by mass of the (A) base polymer. By setting the content of the (A5) ethylene-acrylic acid ester copolymer to 10 parts by mass or more out of 100 parts by mass of the (A) base polymer, sufficient elongation can be obtained as an insulating layer of the insulated wire, and (A) By setting the amount to 30 parts by mass or less out of 100 parts by mass of the base polymer, sufficient wear resistance can be obtained as an insulating layer of an insulated wire.

Further, in the resin composition according to the present embodiment, the amount of the acrylic acid ester of the (A5) ethylene-acrylic acid ester copolymer is preferably 10% by mass or more and 25% by mass or less. By doing so, the adhesion to (B) the metal hydroxide can be enhanced in an appropriate range, and the mechanical properties of the resin composition can be improved.

Examples of the (A5) ethylene-acrylate copolymer include an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, and a butyl ethylene-butyl acrylate copolymer. Copolymers are preferred. As the (A5) ethylene-acrylic acid ester copolymer exemplified here, one of them may be used alone, or two or more kinds thereof may be used in combination. The ethylene-vinyl acetate copolymer cannot be used as the (A5) ethylene-acrylic acid ester copolymer because the deacetic acid reaction occurs in a high temperature environment and the physical properties are significantly deteriorated.

[Metal hydroxide]
Examples of the metal hydroxide (B) according to the present embodiment include magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like, and magnesium hydroxide is preferable. This is because the reaction start temperature of the thermal decomposition reaction (endothermic reaction) of the metal hydroxide is about 350 ° C., which is close to the thermal decomposition temperature of the resin composition, and is highly effective in suppressing the thermal decomposition of the resin composition. is there.

As shown in Examples described later, the resin composition according to the present embodiment contains (A) 140 parts by mass or more and 200 parts by mass or less of (B) metal hydroxide with respect to 100 parts by mass of the base polymer. By setting the content of (B) metal hydroxide to 140 parts by mass or more with respect to 100 parts by mass of (A) base polymer, sufficient flame retardancy can be obtained as an insulating layer of an insulated wire, and (A) base. By setting the amount to 200 parts by mass or less with respect to 100 parts by mass of the polymer, sufficient insulating properties can be obtained as an insulating layer of an insulated wire. Further, as shown in Examples (Examples 1 to 4, 6, 8 to 12) described later, the resin composition according to the present embodiment is (A) a metal (B) with respect to 100 parts by mass of the base polymer. It is preferable that the hydroxide is contained in an amount of 150 parts by mass or more and 180 parts by mass or less. By doing so, it is possible to exhibit sufficient flame retardancy, low temperature characteristics and heat resistance in the insulated wire having the resin composition according to the present embodiment as the insulating layer.

Further, it is preferable to use the metal hydroxide of the present embodiment (B) which has been surface-treated with a silane coupling agent, a titanate-based coupling agent, or a fatty acid such as stearic acid. By doing so, the dispersibility of the metal hydroxide in the resin composition is improved, and as a result, the molding processability and flame retardancy of the resin composition are improved. When high heat resistance is required as the insulating layer of the insulated wire, it is preferable to use a metal hydroxide surface-treated with a silane coupling agent.

[Processing aid]
As described above, the processing aid (C) according to the present embodiment is a metal soap and / or a silicone-based processing aid.

The resin composition according to the present embodiment contains (A) 1 part by mass or more and 10 parts by mass or less of the processing aid with respect to 100 parts by mass of the base polymer. By setting the content of the processing aid (C) to 1 part by mass or more with respect to 100 parts by mass of the (A) base polymer, the generation of dice shavings and nipple shavings can be suppressed. Further, although (C) the processing aid is a combustible material, the above-mentioned resin composition is formed by setting the content of (C) the processing aid to 10 parts by mass or less with respect to 100 parts by mass of the (A) base polymer. The flame retardancy of the above can be fully exhibited.

Further, in the resin composition according to the present embodiment, the processing aid (C) preferably contains a metal soap having a melting point of 120 ° C. or higher, and more preferably contains a metal soap having a melting point of 220 ° C. or higher. By doing so, the lubricity between the die or nipple and the resin composition is effectively enhanced at the temperature during extrusion molding of the resin composition (for example, 130 ° C. to 240 ° C.), and the generation of die residue and nipple residue is generated. It can be prevented more reliably.

Examples of the metal soap include magnesium stearate (melting point 120 ° C.) and magnesium 12-hydroxystearate (melting point 220 ° C.).

Examples of the silicone-based processing aid include organopolysiloxane, and specifically, modification having a functional group such as dimethylpolysiloxane, methylvinylpolysiloxane, methylphenylpolysiloxane, or vinyl group at the end thereof. Examples include polysiloxane.

[Metal chelating agent]
The (D) metal chelating agent according to the present embodiment is also called a copper damage inhibitor or a heavy metal inactivating agent.

The resin composition according to the present embodiment contains (A) 1 part by mass or more and 10 parts by mass or less of the metal chelating agent with respect to 100 parts by mass of the base polymer. By setting the content of the (D) metal chelating agent to 1 part by mass or more with respect to 100 parts by mass of the (A) base polymer, sufficient heat resistance can be obtained as an insulating layer of an insulated wire. Further, by setting the content of the (D) metal chelating agent to 10 parts by mass or less with respect to 100 parts by mass of the (A) base polymer, the (D) metal chelating agent is sufficiently dispersed in the (A) base polymer. It is possible to prevent the resin composition from being cracked in the low temperature bending test due to the generation of whelks.

Examples of the (D) metal chelating agent include hydrazine compounds and salicylic acid derivatives, and specific examples thereof include N, N'-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl). Propionyl] hydrazine, 3- (N-salicyloyl) amino-1,2,4-triazole, N'1, N'12-bis (2-hydroxybenzoyl) dodecandihydrazide, or 2-hydroxy-N-1H-1 , 2,4-Triazole-3-ylbenzoamide, alcohol carboxylic acid ester and the like.

[Other]
In addition to the raw materials described above, the resin composition of the present embodiment contains (E) other components such as (E1) antioxidant, (E2) cross-linking aid, and colorant, as required. Contains chemical cross-linking agents, flame retardants, UV absorbers, light stabilizers, softeners, lubricants, reinforcing materials, surfactants, inorganic fillers, plasticizers, foaming agents, compatibilizers, stabilizers, etc. You may.

Examples of the (E1) antioxidant include phenol-based antioxidants, sulfur-based antioxidants, phenol / thioester-based antioxidants, amine-based antioxidants, and phosphite ester-based antioxidants.

Examples of the (E2) cross-linking aid include trimethylolpropane trimethacrylate (TMPT), triallyl isocyanurate, triallyl cyanurate, N, N'-metaphenylene bismaleimide, ethylene glycol dimethacrylate, zinc acrylate, and methacrylic acid. Examples include zinc acid.

Further, it is preferable that the resin composition constituting the insulating layer of the insulated wire according to the present embodiment is crosslinked. This improves the mechanical properties of the resin composition.

<Manufacturing method of insulated wire>
The insulated wire 10 according to the present embodiment shown in FIG. 1 is manufactured as follows, for example. First, (A) a base polymer, (B) a metal hydroxide, and, if necessary, other raw materials are melt-kneaded to obtain the resin composition of the present embodiment.

As the kneading device for producing the resin composition of the present embodiment, for example, a known kneading device such as a batch type kneader such as a Banbury mixer or a pressurized kneader, or a continuous kneader such as a twin-screw extruder is adopted. can do.

After that, the conductor 1 is prepared, and the resin composition of the present embodiment is extruded by an extrusion molding machine so as to cover the periphery of the conductor 1 to form an insulating layer 2 having a predetermined thickness. By doing so, the insulated wire 10 can be manufactured.

Further, the method for manufacturing the insulated wire 10 of the present embodiment includes a step of forming the insulating layer 2 and then cross-linking the resin composition constituting the insulating layer 2 by, for example, an electron beam cross-linking method or a chemical cross-linking method. .. Although this step is not essential, as described above, it is preferable to include this step because the cross-linking improves the mechanical properties of the resin composition.

When the electron beam cross-linking method is used, the resin composition is formed as a plurality of coating layers 2 of the insulated wire 10, and then cross-linked by irradiating an electron beam of, for example, 1 to 30 Mrad. When the chemical cross-linking method is used, a cross-linking agent is added to the resin composition in advance, the resin composition is formed as the insulating layer 2 of the insulating electric wire 10, and then heat-treated for cross-linking. The compounding composition of the resin composition is also preferable because it can be relatively simplified.

(Example)
Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

<Outline of Examples and Comparative Examples>
Hereinafter, the insulated wires of Examples 1 to 12 and Comparative Examples 1 to 8 will be described. The insulated wires of Examples 1 to 12 correspond to the insulated wires 10 according to the present embodiment shown in FIG. The insulated wires of Comparative Examples 1 to 8 have the same configuration as the insulated wires 10 shown in FIG. 1, but the resin composition constituting the insulating layer 2 is different from that of Examples 1 to 12.

<Manufacturing methods of Examples and Comparative Examples>
The methods for manufacturing the insulated wires of Examples 1 to 12 and Comparative Examples 1 to 8 are as follows. First, each of the raw materials shown in Tables 1 and 2 was dry-blended at room temperature, and the mixed raw materials were melt-kneaded at 130 to 240 ° C. with a 25 L pressure kneader to produce a resin composition. An insulated wire was produced by coating a resin composition pelletized by a granulator around a conductor using an extrusion coating device for manufacturing an electric wire to form an insulating layer. By performing an electron beam cross-linking treatment (5Mrad) on this insulated wire, the resin composition constituting the insulating layer was cross-linked to produce the insulated wires of Examples 1 to 12. The method for manufacturing the insulated wires of Comparative Examples 1 to 8 is the same as that of the insulated wires of Examples 1 to 12, and thus is omitted.

<Ingredients for Examples and Comparative Examples>
The compositions of the resin compositions constituting the insulating layer of the insulated wires of Examples 1 to 12 and Comparative Examples 1 to 8 are shown in Tables 1 and 2.

As the conductors of the insulated wires of Examples 1 to 12 and Comparative Examples 1 to 8, tin-plated copper stranded conductors (19 core wires, wire outer diameter 0.18 mm) were used. The coating thickness of the insulating layer was 0.26 mm.

<Evaluation method of Examples and Comparative Examples>
Examples and comparative examples were evaluated for the properties detailed below. As a comprehensive evaluation, in all of the following characteristic evaluations (1) to (6), those with ◎ or ○ are designated as “◎”, those containing △ are designated as “○”, and those containing × are designated as “○”. It was set as "x".

(1) Low temperature characteristics: Low temperature test The low temperature characteristics of the insulated wire were evaluated by a low temperature winding test. Specifically, the produced electric wire was cooled at −40 ° C. for 4 hours, and then wound around a φ5.6 mm and φ7.0 mm mandrel 6 times. When wound around a φ5.6 mm mandrel, no cracks were observed in the insulating layer as “◎”, and cracks were observed in the φ5.6 mm mandrel, but cracks were observed in the φ7.0 mm mandrel. Those that did not have were marked with "○", and those in which cracks were observed in both the φ5.6 mm and φ7.0 mm mandrels were marked with "x".

(2) Heat resistance: Heat aging test The heat resistance of the insulated wire was evaluated by the heat aging test. Specifically, the produced electric wire was left in an aging tester at 180 ° C. for 100 hours or 168 hours, and wound around a mandrel having a diameter of 5.6 mm 6 times. When the mandrel was wound around the mandrel after being left for 168 hours, no cracks were observed in the insulating layer, and the cracks were observed after being left for 168 hours, but no cracks were observed after being left for 100 hours. Those with cracks observed after being left for 100 hours were marked with "○", and those with cracks were marked with "x".

(3) Flame retardancy: Flame retardant test The flame retardancy of the insulated wire was evaluated by a flame retardant test conforming to the standard EN5035.9.2.1. Specifically, the produced insulated wires are made into one bundle of 37 twists, 14 bundles are arranged vertically at equal intervals, and after burning with a burner for 20 minutes, the carbonization length is 1.0 m or less from the lower end. Was designated as “⊚”, those having a carbonization length of more than 1.0 m and less than 1.5 m were designated as “◯”, and those having a carbonization length of 1.5 m or more were designated as “x”.

(4) Dynamic cut-through resistance: Dynamic cut-through test The dynamic cut-through resistance of the insulated wire was evaluated by a dynamic cut-through test in accordance with the standard EN50305.5.6. Specifically, a cutting blade having a needle at the tip was applied to an insulated wire at a speed of 1 N / sec, and the load at which the insulating layer was cut (mean value of 4 times) was measured. A load of 90 N or more was designated as “⊚”, a load of 70 N or more and less than 90 N was designated as “◯”, and a load of less than 70 N was designated as “x”.

(5) Wire workability The wire workability of the insulated wire was evaluated by the presence or absence of die residue and nipple residue and the DC stability test. Specifically, in the case of manufacturing an insulated wire of 1000 m, there is no die residue during extrusion molding of the insulating layer, or even if die residue is generated, it can be blown off with air, and there is no abnormality in the appearance of the electric wire, and the nipple residue is also present. If there is no die scum, or if there is no dice scum, it can be blown off with air, and if there is no abnormality in the appearance of the wire and a small amount of nipple scum is generated, it is marked as "○". If bumps are generated due to the cause and do not short-circuit for 240 hours or more in the DC stability test described later, they are marked with "Δ", and if bumps are generated due to nipple residue and short-circuited in less than 240 hours in the DC stability test described later, or , The one with a markedly rough appearance of the insulated wire was marked with "x".

(6) Insulation: DC stability test The insulation of the insulated wire was evaluated by a DC stability test in accordance with the standard EN050305.6.7. Specifically, 300 V was applied in a state where the produced insulated wire was immersed in a saline solution having a concentration of 3% by mass at 85 ° C., and the time until a short circuit (dielectric breakdown) was measured. Those having a time until dielectric breakdown of 300 hours or more were designated as "⊚", those having a time of 240 hours or more and less than 300 hours were marked with "○", and those having a time of less than 240 hours were marked with "x".

<Details of Examples and Comparative Examples and Evaluation Results>
Table 1 shows the configurations and evaluation results of Examples 1 to 12. Table 2 shows the configurations and evaluation results of Comparative Examples 1 to 8.

As shown in Table 1, the insulated wires of Examples 1 to 12 have different compositions of the resin composition constituting the insulating layer.

As shown in Table 1, in Examples 1 to 12, the characteristics of (1) to (6) above were all good regardless of the difference in the composition of the resin composition. In particular, Examples 1 to 5 received a higher evaluation than the other examples.

Specifically, Examples 1 to 6, 9 to 12 have a smaller amount of (B) magnesium hydroxide added than in Example 7 and a smaller amount of (D) metal chelating agent added than in Example 8. , (1) Excellent low temperature characteristics as compared with other examples.

In Examples 1 to 6, 8, 11 and 12, the amount of (B) magnesium hydroxide added was smaller than that of Example 7, and the amount of (D) metal chelating agent added was larger than that of Examples 9 and 10. Compared with other examples, (2) heat resistance is excellent.

Examples 6 to 9, 11 and 12 in which the amount of magnesium hydroxide added (B) is larger than that in Examples 1 to 5 and 10 are (3) superior in flame retardancy as compared with other examples. In particular, Example 7 in which (B) a large amount of magnesium hydroxide is added is superior in (4) dynamic cut-through resistance as compared with other examples.

Examples 1 and 7 in which (C) a plurality of metal soaps having different melting points are used in combination with a processing aid, and Examples 2 to 5 in which a metal soap and a silicone-based processing aid are used in combination as a processing aid. 8 to 10 and 12 are (5) excellent in wire workability as compared with other examples. In particular, Example 5 in which (C) a large amount of processing aid is added is particularly excellent in (5) wire workability as compared with other examples.

Examples 1 to 5 in which the amount of (B) magnesium hydroxide added is smaller than in Examples 6 to 9, 11 and 12, and the amount of (A2) maleic anhydride-modified high-density polyethylene added is larger than in Example 10. Is superior in (6) insulating property as compared with other examples.

On the other hand, as shown in Table 2, Comparative Example 1 was rejected due to (3) flame retardancy because the amount of magnesium hydroxide (B) magnesium hydroxide added as a flame retardant was small.

Comparative Example 2 was rejected due to (3) flame retardancy because the amount of the combustible (C) processing aid added was large.

In Comparative Example 3, (C) the amount of the processing aid added was small, so that it was not possible to prevent die scraps and nipple scraps, and in the DC stability test, a short circuit occurred from the bumps derived from the scraps, resulting in (5) electric wires. It was rejected due to workability and (6) insulation.

In Comparative Example 4, the flame retardant (B) magnesium hydroxide was added in a large amount, so that (6) the insulating property was rejected.

In Comparative Example 5, (D) the amount of the metal chelating agent added was small, and therefore (2) heat resistance was rejected.

In Comparative Example 6, since (D) the amount of the metal chelating agent added was large, the dispersibility was lowered and low-temperature cracking occurred, and (1) the low-temperature characteristics were rejected.

Comparative Example 7 was rejected due to (6) insulation because it did not contain (A2) maleic anhydride-modified high-density polyethylene.

In Comparative Example 8, since (A1) high-density polyethylene was not contained, the viscosity at the time of extrusion was too high and the appearance was rough, and in the DC stability test, a short circuit was made from a thin walled portion (5). It was rejected due to wire workability and (6) insulation.

<Summary of Examples and Comparative Examples>
From the results of Examples and Comparative Examples, according to the present invention, a separatorless insulated wire having a single-layer insulating layer has mechanical properties, flame retardancy, insulating properties, low temperature properties, heat resistance, and wire workability. It was shown that it can be done. In particular, it has been clarified that high insulating properties can be obtained by adding (A2) maleic anhydride-modified high-density polyethylene as the (A) base polymer. Then, it was clarified that high wire workability can be obtained by adding an appropriate amount of the processing aid (C) to the (A) base polymer, that is, the generation of dice shavings and nipple shavings can be prevented. Then, it was clarified that high heat resistance can be obtained by adding an appropriate amount of the (D) metal chelating agent to the (A) base polymer.

The present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the gist thereof.

1 Conductor 2 Insulation layer 10 Insulation wire

Claims (8)

It has a conductor and an insulating layer coated around the conductor.
The insulating layer is directly coated on the conductor, and the insulating layer is directly coated on the conductor.
The resin composition constituting the insulating layer contains a base polymer, a metal hydroxide, a processing aid, and a metal chelating agent.
The base polymer is high-density polyethylene, maleic anhydride-modified high-density polyethylene, ethylene-acrylic acid ester-maleic anhydride ternary copolymer, maleic anhydride-modified ethylene-α-olefin copolymer, and ethylene. -Contains with acrylic ester copolymer
The processing aids include metal soaps and / or silicone-based processing aids.
The resin composition contains 5 parts by mass or more and less than 35 parts by mass of the maleic anhydride-modified high-density polyethylene in 100 parts by mass of the base polymer.
The resin composition contains 30 parts by mass or more and less than 50 parts by mass of the ethylene-acrylic acid ester-maleic anhydride ternary copolymer in 100 parts by mass of the base polymer.
The resin composition contains 5 parts by mass or more and 20 parts by mass or less of the maleic anhydride-modified ethylene-α-olefin copolymer in 100 parts by mass of the base polymer.
The resin composition contains 10 parts by mass or more and 30 parts by mass or less of the ethylene-acrylic acid ester copolymer in 100 parts by mass of the base polymer.
The resin composition contains 140 parts by mass or more and 200 parts by mass or less of the metal hydroxide with respect to 100 parts by mass of the base polymer.
The resin composition contains 1 part by mass or more and 10 parts by mass or less of the processing aid with respect to 100 parts by mass of the base polymer.
The resin composition is an insulated electric wire containing 1 part by mass or more and 10 parts by mass or less of the metal chelating agent with respect to 100 parts by mass of the base polymer. In the insulated wire according to claim 1,
The processing aid is an insulated electric wire containing a metal soap having a melting point of 120 ° C. or higher. In the insulated wire according to claim 2,
The processing aid is an insulated electric wire containing a metal soap having a melting point of 220 ° C. or higher. In the insulated wire according to any one of claims 1 to 3,
An insulated wire in which the amount of acrylic acid ester of the ethylene-acrylic acid ester copolymer is 10% by mass or more and 25% by mass or less. In the insulated wire according to any one of claims 1 to 4,
An insulated wire having a glass transition point of the maleic anhydride-modified ethylene-α-olefin copolymer of −55 ° C. or lower. In the insulated wire according to any one of claims 1 to 5,
The resin composition is an insulated electric wire containing 150 parts by mass or more and 180 parts by mass or less of the metal hydroxide with respect to 100 parts by mass of the base polymer. In the insulated wire according to any one of claims 1 to 6,
The metal hydroxide is an insulated electric wire which is magnesium hydroxide. In the insulated wire according to any one of claims 1 to 7,
The resin composition is a crosslinked insulated electric wire.

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