JP2020184469A - Insulated wire - Google Patents

Abstract

To provide an insulated wire which has a hue other than black color and is excellent in flame retardancy and insulatability.SOLUTION: An insulated wire 10 has an electric conductor 1, and a plurality of coating layers 2 coating the periphery of the electric conductor 1. The plurality of coating layers 2 have two or more flame-retardant layers 11, and one or more insulating layers 12 having volume resistivity higher than any one of the two or more flame-retardant layers 11. Volume resistivity of an insulating resin composition constituting each of the one or more insulating layers 12 is 1×1015 Ω cm or more. The resin composition constituting each of the two or more flame-retardant layers 11 includes a base polymer and a metal hydroxide. A volume ratio occupied by the two or more flame-retardant layers 11 among the plurality of coating layers 2 is 80% or more. The first flame-retardant layer 11a among the two or more flame-retardant layers 11 are arranged on the outermost side among the plurality of coating layers 2. The flame-retardant resin composition constituting the first flame-retardant layer 11a does not include carbon black.SELECTED DRAWING: Figure 1

Description

The present invention relates to an insulated electric wire, and more particularly to an insulated electric wire having a multilayer laminated structure as a coating layer.

The insulated wire has a conductor and a coating layer provided around the conductor. The coating layer of the electric 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, electric wires for railway vehicles and automobiles are required to have high insulation, flame retardancy, and oil resistance (fuel resistance).

As an electric wire for the purpose of achieving both insulation and flame retardancy, for example, in Patent Document 1 and Patent Document 2, a multilayer in which an insulating layer having an insulating property and a flame retardant layer having a flame retardancy are arranged. An insulated wire having a coated layer having a laminated structure is described.

Japanese Unexamined Patent Publication No. 2013-214487 JP-A-2018-45884

However, according to the study of the present inventor, it has been confirmed that sufficient insulating properties or flame retardancy may not be obtained depending on the structure of the coating layer having the multilayer laminated structure. Specifically, flame retardancy may not be obtained in an insulated wire having a hue other than black.

The present invention has been made in view of such a problem, and an object of the present invention is to provide an insulated wire having excellent insulation and flame retardancy in an insulated wire having a hue other than black.

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

[1] The insulated wire has a conductor and a plurality of coating layers coated around the conductor, and the plurality of coating layers are composed of two or more flame-retardant layers and the two or more flame-retardant layers. The insulating resin composition having one or more insulating layers having a higher volume resistivity than any of them and constituting each of the one or more insulating layers has a volume resistivity of 1 × 10 ¹⁵ Ω · cm or more. Is. The flame-retardant resin composition constituting each of the two or more flame-retardant layers contains a base polymer and a metal hydroxide, respectively, and the volume ratio occupied by the two or more flame-retardant layers among the plurality of coating layers. Is 80% or more. The first flame-retardant layer of the two or more flame-retardant layers is arranged on the outermost side of the plurality of coating layers, and carbon is included in the flame-retardant resin composition constituting the first flame-retardant layer. Black is not included.

[2] In the insulated wire according to [1], the flame-retardant resin composition constituting the first flame-retardant layer contains a pigment other than black and a dispersant for dispersing the pigment.

[3] In the insulated wire according to [1], carbon black is used in the flame-retardant resin composition constituting each of the flame-retardant layers other than the first flame-retardant layer among the two or more flame-retardant layers. include.

[4] The insulated wire has a conductor and a plurality of coating layers coated around the conductor, and the plurality of coating layers are composed of two or more flame-retardant layers and the two or more flame-retardant layers. The insulating resin composition having one or more insulating layers having a higher volume resistivity than any of them and constituting each of the one or more insulating layers has a volume resistivity of 1 × 10 ¹⁵ Ω · cm or more. Is. The flame-retardant resin composition constituting each of the two or more flame-retardant layers contains a base polymer and a metal hydroxide, respectively, and the volume ratio occupied by the two or more flame-retardant layers among the plurality of coating layers. Is 80% or more. The first flame-retardant layer of the two or more flame-retardant layers is arranged on the outermost side of the plurality of coating layers, and is composed of carbon black in the flame-retardant resin composition constituting the first flame-retardant layer. The amount of carbon black added is less than any of the amounts of carbon black added in the flame-retardant resin compositions constituting each of the flame-retardant layers other than the first flame-retardant layer among the two or more flame-retardant layers.

[5] In the insulated wire according to any one of [1] to [4], the flame-retardant resin compositions constituting each of the two or more flame-retardant layers are contained in 100 parts by mass of the base polymer. On the other hand, the metal hydroxide is contained in an amount of 100 parts by mass or more and 250 parts by mass or less.

[6] In the insulated wire according to any one of [1] to [5], the flame-retardant resin composition constituting each of the two or more flame-retardant layers is contained in the base polymer with ethylene-. It contains a vinyl acetate copolymer and a maleic acid-modified polymer.

[7] In the insulated wire according to any one of [1] to [6], the volume resistivity of the insulating resin composition constituting each of the one or more insulating layers is 1 × 10 ¹⁷ Ω · cm or more.

[8] In the insulated wire according to any one of [1] to [7], the insulating resin compositions constituting each of the one or more insulating layers are antioxidants and / or copper damage prevention, respectively. Contains agents.

[9] In the insulated wire according to any one of [1] to [8], the insulating resin composition constituting each of the one or more insulating layers has a melting point of 100 parts by mass of the base polymer. It contains 40 parts by mass or more of polyethylene at 125 ° C. or higher.

[10] In the insulated wire according to any one of [1] to [9], each of the two or more flame-retardant layers is formed of the one or more insulating layers along the radial direction of the insulated wire. It is laminated alternately with each.

[11] In the insulated wire according to any one of [1] to [10], the second flame-retardant layer of the two or more flame-retardant layers is directly coated on the conductor.

[12] In the insulated wire according to any one of [1] to [11], the insulating resin composition constituting each of the one or more insulating layers is crosslinked.

[13] In the insulated wire according to [12], the flame-retardant resin compositions constituting each of the two or more flame-retardant layers are crosslinked.

According to the present invention, it is possible to provide an insulated wire having a hue other than black and having excellent insulation and flame retardancy.

It is sectional drawing which shows the structure of the insulated electric wire of one Embodiment. It is a cross-sectional view which shows the structure of the insulated wire of another embodiment. It is sectional drawing which shows the structure of the insulated wire of the study example.

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

First, as described above, in an insulated wire provided with a conductor and a coating layer coated around the conductor, it was examined to have a multilayer laminated structure of the coating layer (hereinafter, referred to as an insulating wire of a study example). ..

FIG. 3 is a cross-sectional view showing the structure of the insulated wire of the study example. As shown in FIG. 3, the insulated wire 100 of the study example includes a conductor 1, an insulating layer 120 arranged on the outer periphery of the conductor 1, and a flame-retardant layer 110 arranged on the outer periphery of the insulating layer 120. ..

In the study example, in order to make the insulated wire 100 a non-halogen insulated wire, a metal hydroxide is added to the flame retardant layer 110 as a flame retardant. By doing so, the insulated wire 100 does not generate toxic gas such as hydrogen chloride or dioxin during combustion, so that it is possible to prevent the generation of toxic gas in the event of a fire or a secondary disaster, and incinerate it when it is discarded. Since it does not matter even if it goes, it is useful as an electric wire for railway vehicles.

Although the details will be described later, it has been confirmed by the present inventors that the flame retardant layer 110 to which the metal hydroxide is added has a lower volume resistivity than the insulating layer 120. In other words, if you try to improve the flame retardancy, the insulation will decrease. Therefore, in the insulated wire 100 of the study example, in order to achieve both insulation and flame retardancy in such a non-halogen insulated wire, the coating layer is a two-layer laminated structure of the insulating layer 120 and the flame retardant layer 110. It is supposed to be.

Here, the present inventors have decided to use a hue other than black for the outermost layer of the insulated wire 100 in order to obtain an insulated wire 100 that can be distinguished by hue from the viewpoint of wiring workability and practicality. investigated. Hereinafter, in the present specification, examples of the "hue other than black" include red, green, yellow, blue, brown, orange, purple, pink, and sky blue, and further constitute the outermost layer of the insulated wire. Even when a colorant is not added to the resin composition to be used, that is, when it is not colored, it is included in the “hue other than black”.

Conventionally, in order to form an insulated wire having a black hue, it is common to add carbon black, which is a black pigment, as a colorant to the outermost layer. Carbon black is composed of carbon fine particles having a diameter of about 3 to 500 nm. It is known that carbon black has flame-retardant effects such as carbonization layer formation and radical stabilization during combustion. Therefore, the present inventors have confirmed that the insulated wire 100 having a hue other than black has lower flame retardancy than the insulated wire 100 having a black hue because carbon black is not added.

When manufacturing an insulated wire 100 having a hue other than black, a color masterbatch (color batch) or a dry color (powder) is applied to the flame-retardant layer 110 arranged on the outermost layer of the insulated wire 100 as a colorant. Colorant) is often added. When the flame-retardant layer 110 of the outermost layer is colored in a hue other than black, the amount of the pigment (other than black) added to the base polymer is higher than the amount of carbon black added so as to show sufficient coloration (color development). Need to be more. Therefore, in order to improve the dispersibility of pigments, color master batches and dry colors contain dispersants (pigment dispersants) composed of low molecular weight components (that is, flammable components) such as metal soap or wax in addition to pigments. There is. Therefore, when the flame-retardant layer 110 is colored in a hue other than black, not only the flame retardancy is lowered due to the absence of carbon black as described above, but also the dispersant contained in the color masterbatch or dry color is used. The addition of the above also causes a decrease in flame retardancy.

Therefore, it is difficult to secure the same flame retardancy as the insulated wire 100 having a hue of black in the insulated wire 100 having a hue other than black. For example, when a flame retardant such as a metal hydroxide is further added to the resin composition constituting the flame retardant layer 110, properties other than flame retardancy are deteriorated.

From the above, it is desired that an insulated wire having a hue other than black has a flame-retardant and insulating property by devising its configuration.

(Embodiment)
<Main configuration and effect of the insulated wire according to the first embodiment>
Hereinafter, the insulated wire according to the first 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 first embodiment. As shown in FIG. 1, the insulated wire 10 according to the first embodiment has a conductor 1 and a plurality of coating layers 2 coated around the conductor 1. The plurality of coating layers 2 according to the first embodiment have two or more flame-retardant layers 11 and one or more insulating layers 12 having a volume resistivity higher than any of the two or more flame-retardant layers 11. ing. The volume resistivity of the insulating resin composition constituting each of the one or more insulating layers 12 is 1 × 10 ¹⁵ Ω · cm or more. The resin composition constituting each of the two or more flame-retardant layers 11 contains (FA) -based polymer and (FB) metal hydroxide. The volume ratio of two or more flame-retardant layers 11 among the plurality of coating layers 2 is 80% or more.

In the insulated wire 10 according to the first embodiment, the two or more flame-retardant layers 11 are composed of the first flame-retardant layer 11a and the second flame-retardant layer 11b, and the one or more insulating layers 12 are the first insulation. It consists of layer 12a. Hereinafter, two or more flame-retardant layers 11 may be referred to as flame-retardant layers 11a and 11b, and one or more insulating layers 12 may be referred to as insulating layers 12a, respectively. The first flame-retardant layer 11a of the flame-retardant layers 11a and 11b is arranged on the outermost side of the plurality of coating layers 2. The flame-retardant resin composition constituting the first flame-retardant layer 11a does not contain carbon black.

In addition, in this specification, "carbon black is not contained" means that carbon black is substantially not contained, and does not affect the hue other than black. Carbon black may be added. Generally, when the flame-retardant resin composition is colored black, it is configured to contain 0.2 parts by mass or more and 5 parts by mass or less of carbon black with respect to 100 parts by mass of the (FA) base polymer. (FA) The case where carbon black is contained in an amount of less than 0.2 parts by mass with respect to 100 parts by mass of the base polymer is included in the case where "carbon black is not contained".

In the first embodiment of the present invention, by adopting such a configuration, the insulated wire 10 having a hue other than black can be provided with flame retardancy and insulating property. The reason will be specifically described below.

As described above, the insulated wire (non-halogen insulated wire) 100 of the study example shown in FIG. 3 has a problem that the flame retardancy is lowered because carbon black is not added when the hue is configured to be other than black.

On the other hand, as shown in FIG. 1, in the insulated wire 10 according to the first embodiment, a plurality of coating layers 2 coated around the conductor 1 are provided with two or more flame-retardant layers 11. It is composed of one or more insulating layers 12 having a volume resistivity higher than any of the two or more flame-retardant layers 11, and the volume ratio of two or more flame-retardant layers 11 among the plurality of coating layers 2 is 80% or more. is there. By doing so, even if the non-halogen insulated wire and the flame-retardant resin composition constituting the outermost first flame-retardant layer 11a does not contain carbon black, the insulated wire 10 is difficult. Can be flammable. Then, by setting the volume resistivity of the insulating resin composition constituting each of the one or more insulating layers 12 to 1 × 10 ¹⁵ Ω · cm or more, the insulated wire 10 can be provided with insulating properties. As a result, the insulated wire 10 having a hue other than black can be provided with flame retardancy and insulation.

The first flame-retardant layer 11a according to the first embodiment is arranged on the outermost side of the plurality of covering layers 2, but the "first" is for convenience and 2 Any of the above flame-retardant layers 11 may be arranged on the outermost side of the plurality of coating layers 2. On the other hand, when any one or more of the insulating layers 12 containing no flame retardant such as (FB) metal hydroxide is arranged on the outermost side of the plurality of covering layers 2, it is arranged along the length direction of the insulated wire 10. It is not preferable because it may spread the fire.

Further, as shown in Examples (Examples 1 to 15) described later, in the insulated wire 10 according to the first embodiment shown in FIG. 1, the flame retardancy constituting the first flame retardant layer 11a is formed. The resin composition preferably contains a pigment other than black and a dispersant for dispersing the pigment. As described above, when the first flame-retardant layer 11a, which is the outermost layer, is colored in a hue other than black, it is necessary to add a large amount of a pigment other than black together with a dispersant which is a low molecular weight component (flammable component). There is. In the insulated wire 10 according to the first embodiment, even when the outermost first flame-retardant layer 11a is colored in a hue other than black, it is sufficiently difficult to have the above configuration. Flammability can be ensured.

Further, as shown in Examples (Examples 1 and 7 to 15) described later, in the insulated wire 10 according to the first embodiment shown in FIG. 1, among two or more flame-retardant layers 11, It is preferable that the flame-retardant resin composition constituting the flame-retardant layer other than the first flame-retardant layer 11a, that is, the second flame-retardant layer 11b contains carbon black. By doing so, even when the first flame-retardant layer 11a, which is the outermost layer, has a hue other than black, the flame retardancy of the insulated wire 10 can be improved.

In the insulated wire 10 according to the first embodiment, instead of making the flame-retardant resin composition constituting the outermost first flame-retardant layer 11a not containing carbon black, the first The amount of carbon black added to the flame-retardant resin composition constituting the flame-retardant layer 11a is set to a flame-retardant layer other than the first flame-retardant layer 11a among two or more flame-retardant layers 11, that is, a second flame-retardant layer. The amount of carbon black added to the flame-retardant resin composition constituting 11b may be less than any of the addition amounts. By doing so, the first flame-retardant layer 11a, which is the outermost layer, has a hue other than black, and the flame-retardant layer other than the first flame-retardant layer 11a, that is, the second flame-retardant layer 11b is flame-retardant. It can be enhanced to ensure sufficient flame retardancy as the insulated wire 10.

Further, as shown in FIG. 1, in the insulated wire 10 according to the first embodiment, which is a preferable embodiment, the second flame-retardant layer 11b of the two or more flame-retardant layers 11 is directly coated on the conductor 1. Has been done. For example, when the conductor 1 is configured as a twisted conductor, the surface of the conductor 1 may be uneven and the electric field may be concentrated to cause dielectric breakdown. In this respect, in the insulated wire 10 according to the first embodiment, which is a preferable embodiment, the second flame-retardant layer 11b is directly coated on the conductor 1 to form the second flame-retardant layer 11b as described above. The flame-retardant resin composition to be used contains (FB) metal hydroxide. In this way, by covering the surface of the conductor 1 with the flame retardant layer 11 having a lower volume resistivity than the insulating layer 12, the electric field concentration on the surface of the conductor 1 can be relaxed, and as a result, dielectric breakdown is caused. Can be prevented.

Further, as shown in FIG. 1, in the insulated wire 10 according to the first embodiment, which is a preferable embodiment, each of the two or more flame-retardant layers 11 is one or more along the radial direction of the insulated wire 10. It is alternately laminated with each of the insulating layers 12. That is, the plurality of coating layers 2 are arranged in the order of the second flame-retardant layer 11b, the first insulating layer 12a, and the first flame-retardant layer 11a from the conductor 1 side to the outside along the radial direction of the insulated wire 10. It is laminated. As described above, the flame-retardant layers 11a and 11b containing the (FB) metal hydroxide have a lower volume resistivity than the insulating layer 12a, which constitutes the flame-retardant layers 11a and 11b (FA). This is because the affinity between the base polymer and the (FB) metal hydroxide is not high, so that minute gaps are formed around the (FB) metal hydroxide in the flame-retardant layers 11a and 11b, and water is easily absorbed. it is conceivable that. On the other hand, since the insulating layer 12a does not contain metal hydroxide, almost no water permeates. Therefore, by alternately laminating the flame-retardant layers 11a and 11b and the insulating layer 12a along the radial direction of the insulating electric wire 10, the flame-retardant layer 11b is covered with the insulating layer 12a and water is supplied to the flame-retardant layer 11b. Penetration can be suppressed.

Further, as shown in FIG. 1, in the insulated wire 10 according to the first embodiment, each of the one or more insulating layers 12, that is, the insulating resin composition constituting the first insulating layer 12a is It is preferably crosslinked. By doing so, the molecular structure of the insulating resin composition can be strengthened to improve the mechanical properties and water-shielding properties of the insulating layer 12a, and further, the thickness of the insulating layer 12a can be reduced. ..

Similarly, as shown in FIG. 1, in the insulated wire 10 according to the first embodiment, the flame-retardant resins constituting the two or more flame-retardant layers 11, that is, the flame-retardant resins 21a and 21b, respectively. The composition is preferably crosslinked. By doing so, the molecular structure of the flame-retardant resin composition can be strengthened and the mechanical properties can be improved.

<Main configuration and effect of the insulated wire according to the second embodiment>
Hereinafter, the insulated wire according to the second embodiment of the present invention will be described with reference to the drawings. In the figure showing the second embodiment, the same or similar parts or components as the insulated wire of the first embodiment are indicated by the same or similar symbols or reference numbers, and the description is not repeated in principle. , Omitted.

FIG. 2 is a cross-sectional view showing an insulated wire according to the second embodiment. As shown in FIG. 2, the insulated wire 20 according to the second embodiment is the same as the insulated wire 10 according to the first embodiment, the conductor 1 and a plurality of coatings coated around the conductor 1. It has a layer 2. The plurality of coating layers 2 according to the second embodiment have two or more flame-retardant layers 21 and one or more insulating layers 22 having a volume resistivity higher than that of any of the two or more flame-retardant layers 21. ing. The volume resistivity of the insulating resin composition constituting each of the one or more insulating layers 22 is 1 × 10 ¹⁵ Ω · cm or more. The resin composition constituting each of the two or more flame-retardant layers 21 contains (FA) -based polymer and (FB) metal hydroxide. The volume ratio of two or more flame-retardant layers 21 among the plurality of coating layers 2 is 80% or more.

In the insulated wire 20 according to the second embodiment, the two or more flame-retardant layers 21 are composed of a first flame-retardant layer 21a, a second flame-retardant layer 21b, and a third flame-retardant layer 21c, and have one or more insulation. The layer 22 is composed of a first insulating layer 22a and a second insulating layer 22b. Hereinafter, two or more flame-retardant layers 21 may be referred to as flame-retardant layers 21a, 21b, 21c, and one or more insulating layers 22 may be referred to as insulating layers 22a, 22b, respectively. The first flame-retardant layer 21a of the flame-retardant layers 21a, 21b, 21c is arranged on the outermost side of the plurality of coating layers 2. The flame-retardant resin composition constituting the first flame-retardant layer 21a does not contain carbon black.

From the above, the insulated wire 20 according to the second embodiment having a hue other than black can be provided with flame retardancy and insulating property as in the insulated wire 10 according to the first embodiment.

Further, in the insulated wire 20 according to the second embodiment shown in FIG. 2, among the two or more flame-retardant layers 21, the flame-retardant layers other than the first flame-retardant layer 21a, that is, the second flame-retardant layer. The flame-retardant resin composition constituting the 21b and the third flame-retardant layer 21c preferably contains carbon black. By doing so, even when the first flame-retardant layer 21a, which is the outermost layer, has a hue other than black, the flame retardancy of the insulated wire 20 can be improved.

Further, as shown in FIG. 2, in the insulated wire 20 according to the second embodiment, which is a preferable embodiment, the third flame-retardant layer 21c of the two or more flame-retardant layers 21 is directly coated on the conductor 1. Has been done. In this way, by covering the surface of the conductor 1 with the flame retardant layer 21 having a lower volume resistivity than the insulating layer 22, the electric field concentration on the surface of the conductor 1 can be relaxed, and as a result, dielectric breakdown is caused. Can be prevented.

Further, as shown in FIG. 2, in the insulated wire 20 according to the second embodiment, which is a preferable embodiment, each of the two or more flame-retardant layers 21 is one or more along the radial direction of the insulated wire 20. It is alternately laminated with each of the insulating layers 22. That is, the plurality of coating layers 2 have a third flame-retardant layer 21c, a second insulating layer 22b, a second flame-retardant layer 21b, and a second flame-retardant layer 21c from the conductor 1 side to the outside along the radial direction of the insulating electric wire 20. The 1 insulating layer 22a and the first flame retardant layer 21a are laminated in this order. In this way, the flame-retardant layers 21a, 21b, 21c and the insulating layers 22a, 22b are alternately laminated along the radial direction of the insulating wire 20, so that the flame-retardant layers 21b, 21c are covered with the insulating layer 22a. Permeation of water into the flame-retardant layers 21b and 21c can be suppressed.

Further, as shown in FIG. 2, in the insulated wire 20 according to the second embodiment, the insulating resin composition constituting one or more insulating layers 22, that is, the insulating layers 22a and 22b, is used. It is preferably crosslinked. By doing so, the molecular structure of the insulating resin composition can be strengthened to improve the mechanical properties and water-shielding properties of the insulating layers 22a and 22b, and the thickness of the insulating layers 22a and 22b can be reduced. Is also possible.

Similarly, as shown in FIG. 2, in the insulated wire 20 according to the second embodiment, the flame retardants constituting the two or more flame retardant layers 21, that is, the flame retardant layers 21a, 21b, 21c, respectively. The sex resin composition is preferably crosslinked. By doing so, the molecular structure of the flame-retardant resin composition can be strengthened and the mechanical properties can be improved.

<Conductor composition>
Hereinafter, the configuration of the conductor 1 used in the insulated wire 10 according to the first embodiment of the present invention and the insulated wire 20 according to the second embodiment will be described.

As the conductor 1 shown in FIGS. 1 and 2, in addition to commonly used metal wires such as copper wire and copper alloy wire, aluminum wire, gold wire, silver wire and 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 wires 10 and 20. 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 coating layer>
Hereinafter, the configurations of the plurality of coating layers 2 used for the insulated wire 10 according to the first embodiment of the present invention and the insulated wire 20 according to the second embodiment will be described.

As described above, the flame-retardant layers 11a and 11b of the insulated wire 10 shown in FIG. 1 and the flame-retardant layers 21a, 21b and 21c of the insulated wire 20 shown in FIG. 2 are one embodiment of the present invention described in detail below, respectively. Consists of a flame-retardant resin composition according to the above form. Similarly, the insulating layer 12a of the insulated wire 10 shown in FIG. 1 and the insulating layers 22a and 22b of the insulated wire 20 shown in FIG. 2 each have an insulating resin composition according to an embodiment of the present invention described in detail below. It consists of things.

The total thickness of the plurality of coating layers 2 is not particularly limited, but is preferably 0.15 mm or more and 2 mm or less to which the present invention can be effectively applied, and is in the range where flame retardancy is most required. More preferably, it is 0.15 mm or more and 0.8 mm or less.

The thicknesses of the flame-retardant layers 11a and 11b and the insulating layer 12a shown in FIG. 1 are configured such that the volume ratio occupied by two or more flame-retardant layers 11 among the plurality of coating layers 2 is 80% or more. Often, it can be changed as needed. However, from the viewpoint of improving flame retardancy, the outermost layers, the first flame retardant layer 11a shown in FIG. 1 and the first flame retardant layer 21a shown in FIG. 2, are made thicker than the other coating layers. Is preferable.

Further, the thicknesses of the insulating layers 12a shown in FIG. 1 and the insulating layers 22a and 22b shown in FIG. 2 are not particularly limited as long as the desired insulating properties can be obtained, but stable insulating properties can be obtained. From the viewpoint, the thickness of the insulating layer 12a shown in FIG. 1 and the insulating layers 22a and 22b shown in FIG. 2 is preferably 0.05 mm or more. Therefore, as shown in FIG. 1, when one or more insulating layers 12 are composed of one insulating layer 12a, the thickness of the insulating layer 12a is set to 0.05 mm, and the thickness of the first flame-retardant layer 11a is set to 0. When the thickness of the second flame-retardant layer 11b is 63 mm and the thickness of the second flame-retardant layer 11b is 0.1 mm, the volume ratio occupied by two or more flame-retardant layers 11 among the plurality of coating layers 2 is 95%. Therefore, in order to achieve both flame retardancy and stable insulation, the volume ratio of two or more flame retardant layers 11 among the plurality of coating layers 2 is preferably 80% or more and 95% or less, which is a high difficulty. It is more preferably 89% or more and 95% or less in order to exhibit flammability.

[Structure of flame-retardant resin composition]
Hereinafter, the flame-retardant resin composition according to the present embodiment will be described in detail. The resin compositions constituting each of the two or more flame-retardant layers described above may be the same as or different from each other. Therefore, unless otherwise specified, the composition common to the flame-retardant resin compositions constituting each of the two or more flame-retardant layers will be described below.

The flame-retardant resin composition according to the present embodiment contains (FA) -based polymer and (FB) metal hydroxide.

For the (FA) base polymer according to the present embodiment, for example, polyolefin, polyamide-imide (PAI), or the like can be used, but the present invention is not particularly limited, and the tensile strength and elongation required for the insulated wire can be determined. It can be appropriately selected according to the mechanical characteristics. Examples of the polyolefin include polyethylene and polypropylene. Examples of polyethylene include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methylacrylate copolymer, and ethylene-ethyl. Examples thereof include an acrylate copolymer and an ethylene-glycidyl methacrylate copolymer. These polyolefins may be used alone or in combination of two or more.

The (FA) base polymer according to the present embodiment preferably contains (FA1) ethylene-vinyl acetate copolymer, and in particular, the vinyl acetate content (VA amount) is 10% by mass or more and 40% by mass or less. Ethylene-vinyl acetate copolymers are more preferred. By doing so, the flame retardancy of the flame retardant resin composition can be improved.

Further, the (FA) base polymer according to the present embodiment preferably further contains (FA2) maleic anhydride-modified polymer. The (FA2) maleic anhydride-modified polymer has high affinity with both (FA1) ethylene-vinyl acetate copolymer and (FB) metal hydroxide, and therefore has high tensile properties of the flame-retardant resin composition. Can be improved. As the (FA2) maleic acid-modified polymer, a maleic acid-modified ethylene-α-olefin copolymer is preferable, and a maleic acid-modified ethylene-1-butene copolymer, a maleic acid-modified ethylene-ethyl acrylate copolymer, or a maleic acid. Modified polyethylene is particularly preferred. The maleic acid-modified ethylene-α-olefin-based copolymer is obtained by graft-polymerizing maleic anhydride on an ethylene-α-olefin-based copolymer such as an ethylene-propylene copolymer. The α-olefin preferably has 3 to 8 carbon atoms.

The (FB) metal hydroxide according to this embodiment acts as a flame retardant. Specifically, when a resin composition containing a metal hydroxide is heated and burned, the metal hydroxide decomposes and dehydrates, and the released water lowers the temperature of the resin composition, resulting in a combustion reaction. Can be suppressed. Examples of the (FB) metal hydroxide include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, and a solid solution of nickel in these. These metal hydroxides may be used alone or in combination of two or more.

Further, from the viewpoint of adjusting the affinity with the (FA) base polymer and controlling the mechanical properties of the flame-retardant resin composition, the (FB) metal hydroxide is a silane coupling agent or a titanate-based coupling agent. , It is preferable that the surface is treated with a fatty acid such as stearic acid or a fatty acid salt (fatty acid metal) such as stearate.

In the flame-retardant resin composition according to the present embodiment, the content of the (FB) metal hydroxide with respect to the (FA) base polymer is appropriately changed according to the flame retardancy and mechanical properties required for the insulated wire. be able to. However, in the flame-retardant resin composition according to the present embodiment, in order to have sufficient flame retardancy and mechanical properties, (FB) metal hydroxide is added to 100 parts by mass of the (FA) base polymer. It is preferable to contain 100 parts by mass or more and 250 parts by mass or less. This is because if the amount of the (FB) metal hydroxide is less than 100 parts by mass with respect to 100 parts by mass of the (FA) base polymer, flame retardancy that passes the flame retardancy test described later may not be obtained. .. Further, when the amount of the (FB) metal hydroxide exceeds 250 parts by mass with respect to 100 parts by mass of the (FA) base polymer, the mechanical properties as the coating layer of the insulated wire, particularly the elongation rate, deteriorates.

Further, the flame-retardant resin composition according to the present embodiment may further contain a (FC) antioxidant, a (FD) lubricant, and a (FE) colorant.

Examples of the (FC) antioxidant according to the present embodiment include a phenol-based antioxidant, a sulfur-based antioxidant, a phenol / thioester-based antioxidant, an amine-based antioxidant, and a phosphite ester-based antioxidant. Can be mentioned. Examples of the phenolic antioxidant include 1,3,5-tris [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] -1,3,5-triazine-2,4. , 6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3- (3,5-di-tert-butyl- Examples thereof include stearyl (4-hydroxyphenyl) propionate and 4,4'-butylidenebis- (6-tert-butyl-3-methylphenol). Sulfur-based antioxidants include ditetradecyl 3,3'-thiodipropionic acid, bis [3- (dodecylthio) propionic acid] 2,2-bis [[3- (dodecylthio) -1-oxopropyloxy] methyl]. Examples thereof include -1,3-propanediyl and dioctadecyl 3,3'-thiodipropionate.

Examples of the (FD) lubricant according to the present embodiment include zinc stearate, silicone, fatty acid amide, hydrocarbon, ester, alcohol, and metal soap.

Examples of the (FE) colorant according to the present embodiment include pigment only, dry color (powder colorant), granular colorant, color masterbatch (colorant masterbatch), and the like. When coloring black, it is preferable to add carbon black. On the other hand, when coloring a hue other than black, it is preferable to add a color masterbatch in which the pigment is dispersed in the resin composition from the viewpoint of preventing uneven coloring. Here, except when only a pigment is used as the (FE) colorant, the (FE) colorant contains a dispersant which is a low molecular weight component (flammable component) such as metal soap or wax. As a result, the pigment is dispersed by the dispersant and uneven coloring can be prevented.

Here, the first flame-retardant layer 11a arranged on the outermost side of the plurality of covering layers 2 of the insulated wire 10 of the first embodiment described above, or the insulated wire 20 of the second embodiment. The flame-retardant resin composition constituting the first flame-retardant layer 21a arranged on the outermost side of the plurality of coating layers 2 is colored in a hue other than black. That is, the flame-retardant resin compositions constituting the first flame-retardant layers 11a and 21a do not contain carbon black. On the other hand, a plurality of flame-retardant layers 11b other than the first flame-retardant layer 11a among the plurality of coating layers 2 of the insulated wire 10 of the first embodiment described above, or a plurality of insulated wires 20 of the second embodiment. In the flame-retardant resin composition constituting the flame-retardant layers 21b and 21c other than the first flame-retardant layer 21a in the coating layer 2, the flame retardancy can be improved regardless of the presence or absence of carbon black. Therefore, it is preferable that carbon black is contained.

Further, the flame-retardant resin composition according to the present embodiment may contain a cross-linking agent, a cross-linking aid, and the like in addition to the raw materials described above. The cross-linking agent is added when the flame-retardant resin composition is cross-linked by a chemical cross-linking method. Examples of the cross-linking agent include organic peroxides such as hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxy ester, ketone peroxy ester, and ketone peroxide. Crosslinking aids are those that crosslink with (FA) based polymers, such as trimethylolpropane trimethacrylate (TMPT), triallyl isocyanurate, triallyl cyanurate, N, N'-metaphenylene bis. Polyfunctional monomers such as maleimide and ethylene glycol dimethacrylate can be used. The blending amount (addition amount) of the cross-linking aid in the flame-retardant resin composition according to the present embodiment is not particularly limited, but the gel fraction of the cross-linked flame-retardant resin composition is 10% or more and 100. It is preferable to mix (add) so as to be less than%. By doing so, the mechanical properties of the flame-retardant layer made of the crosslinked flame-retardant resin composition can be effectively improved.

[Structure of Insulating Resin Composition]
Hereinafter, the insulating resin composition according to the present embodiment will be described in detail. When the number of the above-mentioned one or more insulating layers is two or more, the resin compositions constituting each of the one or more insulating layers may contain the same ones or may be different from each other. Therefore, the composition common to the insulating resin compositions constituting each of the one or more insulating layers will be described below.

The insulating resin composition according to this embodiment contains an (IA) base polymer. Further, the insulating resin composition according to the present embodiment may further contain (IB) antioxidant and (IC) copper damage inhibitor. The volume resistivity of the insulating resin composition according to the present embodiment is 1 × 10 ¹⁵ Ω · cm or more, preferably 1 × 10 ¹⁷ Ω · cm or more. The upper limit of the volume resistivity of the insulating resin composition according to the present embodiment is not limited. Here, the volume resistivity of the insulating resin composition means the volume resistivity evaluated in accordance with JIS C 2151: 2019. When the volume resistivity of the insulating resin composition according to the present embodiment is less than 1 × 10 ¹⁵ Ω · cm, for example, the insulated wire specified in the standard EN50305.6.7 is immersed in water. In a DC stability test in which a predetermined voltage is applied, the test may not pass.

As the (IA) base polymer according to the present embodiment, for example, the same resin as the (FA) base polymer constituting the flame-retardant resin composition according to the present embodiment described above can be used, but a polyolefin resin can be used. Is preferable. In particular, as the (IA) base polymer, polyethylene is more preferable because it has a low water absorption rate, good moldability, relatively large breaking elongation, and is inexpensive.

When oil resistance is required for an insulated wire having an insulating layer made of the insulating resin composition according to the present embodiment, the insulating resin composition according to the present embodiment is based on (IA). It is preferable that 40 parts by mass or more of polyethylene having a (IA1) melting point of 125 ° C. or higher (more preferably 127 ° C. or higher) is contained in 100 parts by mass of the polymer. For example, since the oil resistance test specified in the standard EN60811-2-1 carried out in the examples described later is performed under the condition of 100 ° C., the crystal portion of polyethylene having a melting point near 100 ° C. is dissolved during the test, and the resin This is because the oil easily penetrates into the composition. According to the study of the present inventor, 40 parts by mass or more of polyethylene having a (IA1) melting point of 125 ° C. or higher (more preferably 127 ° C. or higher) is contained in 100 parts by mass of the (IA) base polymer. It has been found that the oil resistance can be improved in an insulated electric wire having an insulating layer made of the insulating resin composition. There is no particular upper limit to the amount of polyethylene (IA1) having a melting point of 125 ° C. or higher (more preferably 127 ° C. or higher), but if flexibility is required for the insulated wire, the (IA) base polymer 100 In parts by mass, it is preferable to contain 70 parts by mass or less of polyethylene having a melting point (IA1) of 125 ° C. or higher (more preferably 127 ° C. or higher). This is because polyethylene having a high melting point has a large amount of crystals and is hard, and if it is contained in a large amount, the flexibility of the resin composition decreases.

Further, the insulating resin composition according to the present embodiment may further contain (IB) antioxidant and (IC) copper damage inhibitor.

The (IB) antioxidant according to the present embodiment includes a phenol-based antioxidant, a sulfur-based antioxidant, a phenol / thioester-based antioxidant, and an amine-based oxidation, similarly to the above-mentioned (FC) antioxidant. Examples thereof include inhibitors and phosphite ester-based antioxidants.

Examples of the (IC) copper damage inhibitor according to the present embodiment include N'1, N'12-bis (2-hydroxybenzoyl) dodecandihydrazide and N, N'-bis [3- (3,5-). Di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, hydrazines such as bis-isophthalate (2-phenoxypropionylhydrazine) and 2-hydroxy-N-1H-1,2,4-triazole-3-ylbenzoamide , Alcohol carboxylic acid ester and the like.

Similar to the flame-retardant resin composition according to the present embodiment, the insulating resin composition according to the present embodiment contains the above-mentioned cross-linking agent, cross-linking aid and the like in addition to the raw materials described above. You may. The blending amount (addition amount) of the cross-linking aid in the insulating resin composition according to the present embodiment is not particularly limited, but the gel content of the cross-linked insulating resin composition is 10% or more and 100% or less. It is preferable to mix (add) so as to be. By doing so, the water impermeability and mechanical properties of the insulating layer made of the crosslinked insulating resin composition can be effectively improved.

<Manufacturing method of insulated wire>
Hereinafter, the insulated wire 10 according to the first embodiment shown in FIG. 1 and the insulated wire 20 according to the second embodiment shown in FIG. 2 are manufactured as follows, for example. First, a raw material containing (FA) base polymer, (FB) metal hydroxide,, if necessary, (FC) antioxidant, (FD) lubricant, and (FE) colorant is melt-kneaded. , To obtain the flame-retardant resin composition of the present embodiment. Further, the raw material containing the (IA) base polymer,, if necessary, the (IB) antioxidant and the (IC) copper damage inhibitor is melt-kneaded to obtain the insulating resin composition of the present embodiment. ..

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

After that, the conductor 1 is prepared, and the flame-retardant resin composition and the insulating resin composition of the present embodiment are extruded by an extrusion molding machine so as to cover the periphery of the conductor 1, and a plurality of predetermined thicknesses are extruded. The coating layer 2 is formed. By doing so, the insulated wires 10 and 20 can be manufactured.

Here, in the insulated wire 10 shown in FIG. 1, it is preferable that the second flame-retardant layer 11b, the first insulating layer 12a, and the first flame-retardant layer 11a are formed on the conductor 1 by simultaneous extrusion. Similarly, in the insulated wire 20 shown in FIG. 2, the third flame-retardant layer 21c, the second insulating layer 22b, the second flame-retardant layer 21b, the first insulating layer 22a, and the first flame-retardant layer 21a are conductors. It is preferably formed on 1 by simultaneous extrusion.

By doing so, in the insulated wire 10 according to the first embodiment shown in FIG. 1, between the second flame-retardant layer 11b and the first insulating layer 12a, and between the first insulating layer 12a and the first. It is possible to prevent dust or the like in the atmosphere from adhering to the flame-retardant layer 11a and causing dielectric breakdown due to electric field concentration (with respect to the insulated wire 20 according to the second embodiment shown in FIG. 2). The same applies.).

At this time, as shown in Examples (Examples 2 to 6) described later, in the insulated wire 10 according to the first embodiment shown in FIG. 1, each of the two or more flame-retardant layers 11 is the same. It is preferable that each of the one or more insulating layers 12 is composed of the same insulating resin composition. By doing so, the manufacturing cost can be reduced, and the simultaneous extrusion of the first flame-retardant layer 11a and the second flame-retardant layer 11b becomes easier.

Further, in the method for manufacturing the insulated wire 10 of the present embodiment, after forming the plurality of coating layers 2, each insulating resin composition constituting one or more insulating layers 12 and / or two or more insulating resin compositions. The step of cross-linking each flame-retardant resin composition constituting the flame-retardant layer 11 by, for example, an electron beam cross-linking method or a chemical cross-linking method is included. This step is not essential, but as described above, since cross-linking improves the mechanical properties and water-shielding properties of the insulating resin composition and the mechanical properties of the flame-retardant resin composition, this step may be included. preferable.

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 insulating resin composition and / or the flame-retardant resin composition in advance, and these resin compositions are formed as a plurality of coating layers 2 of the insulating electric wire 10. After that, it is heat-treated and crosslinked. The compounding composition of the resin composition is also preferable because it can be relatively simplified.

In the present embodiment, an electron beam cross-linking method is used in which the compounding composition can be relatively simplified regardless of the type of the base polymer constituting the resin composition. In particular, if the thickness of the plurality of coating layers 2 in the insulated wire 10 of the present embodiment (for example, 0.15 mm or more and 2 mm or less), electron beams can reach all the coating layers, so that simultaneous cross-linking is possible. Is.

(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 15 and Comparative Examples 1 to 3 will be described. The insulated wires of Examples 1 to 15 correspond to the insulated wires 10 according to the first embodiment shown in FIG. That is, as shown in FIG. 1, the insulated wires of Examples 1 to 15 are laminated in the order of the flame-retardant layer (innermost layer) 11b, the insulating layer 12a, and the flame-retardant layer (outermost layer) 11a from the conductor 1 side. It has a coating layer 2 of layers. The insulated wire of Comparative Example 2 has the same configuration as the insulated wire 10 shown in FIG. 1, but the volume ratio occupied by the flame-retardant layer among the plurality of coating layers is different from that of the other examples. The insulated wire of Comparative Example 1 has a structure similar to that of the insulated wire 100 shown in FIG. 3, but has two coating layers in which a flame-retardant layer and an insulating layer are laminated in this order from the conductor side. .. The insulated wire of Comparative Example 3 does not have an insulating layer, but has a coating layer in which two flame-retardant layers are laminated from the conductor side.

<Manufacturing methods of Examples and Comparative Examples>
The methods for manufacturing the insulated wires of Examples 1 to 15 and Comparative Examples 1 to 3 are as follows. First, the raw materials of Difficulty 1 to 8 and Absolute 1 to 6 shown in Tables 1 and 2 are dry-blended at room temperature, and the mixed raw materials are melt-kneaded by a pressure kneader at a start temperature of 40 ° C and an end temperature of 190 ° C. Then, a flame-retardant resin composition and an insulating resin composition were produced. After that, an insulated electric wire was produced by forming a flame-retardant layer made of a flame-retardant resin composition and an insulating layer made of an insulating resin composition around the conductor using an extrusion coating device for manufacturing an electric wire. .. By performing an electron beam cross-linking treatment (5Mrad) on this insulated wire, the resin compositions constituting the plurality of coating layers were cross-linked to produce the insulated wires of Examples 1 to 15. The method for manufacturing the insulated wires of Comparative Examples 1 to 3 is the same as that of the insulated wires of Examples 1 to 15, and will be omitted.

<Raw materials of Examples and Comparative Examples>
The compositions of the resin compositions constituting the plurality of coating layers of the insulated wires of Examples 1 to 15 and Comparative Examples 1 to 3 are shown in Tables 1 and 2.

Specifically, among the plurality of coating layers, Table 1 shows the composition of the flame-retardant resin composition constituting the flame-retardant layer, and Table 2 shows the composition of the insulating resin composition constituting the insulating layer. Each is shown. In Tables 3 and 4 described later, for example, "difficulty 1" or "absolute 1" is described as the configuration of the flame-retardant layer or the insulating layer, but "difficulty 1" or "difficulty 1" shown in Table 1 or Table 2, respectively. It corresponds to the composition of "Zetsu 1".

Further, as the conductors of the insulated wires of Examples 1 to 15 and Comparative Examples 1 to 3, tin-plated copper stranded conductors having an outer diameter of 1.25 mm (37 core wires, wire outer diameter 0.18 mm) were used.

<Evaluation method of Examples and Comparative Examples>
(1) DC stability The DC stability of the insulated wire was evaluated by a DC stability test in accordance with the standard EN50305.6.7. Specifically, 1500 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 dielectric breakdown was measured. Those having a time until dielectric breakdown of 240 hours or more were designated as “◯” as having sufficiently high DC stability, and those having a time of less than 240 hours were designated as “x”.

(2) Flame retardancy: Vertical combustion test (VFT)
The flame retardancy of the insulated wire was evaluated by a vertical combustion test in accordance with the standard EN60332-1-2. Specifically, the prepared insulated wire having a length of 600 mm was kept vertical and exposed to flame for 60 seconds. If the flame is extinguished from the insulated wire during the 60-second ignition, it is marked as "◎" with a margin, and if the flame is extinguished within 60 seconds after being removed, it is marked as "○" and within 60 seconds. Those that did not extinguish the fire were marked as "x".

(3) Flame retardancy: Vertical tray combustion test (VTFT)
The flame retardancy of the insulated wire was evaluated by a vertical tray combustion test conforming to the standard EN50266-2-4. Specifically, an insulated wire with a total length of 3.5 m is made into one bundle of 7 twists, 11 bundles are arranged vertically at equal intervals, burned for 20 minutes, self-extinguished, and the carbonization length is from the lower end. The target was 2.5 m or less. If the carbonization length is 1.5 m or less, the result is "◎" with a margin, and if the carbonization length is more than 1.5 m and 2.5 m or less, the result is "○" and the carbonization length is 2. Those exceeding 5 m were marked as rejected "x".

(4) Oil resistance The oil resistance of the insulated wire was evaluated by an oil resistance test conforming to the standard EN60811-2-1. Specifically, a conductor was pulled out from the produced insulated wire to prepare a sample having only a coating layer, and this sample was immersed in IRM902 oil at 100 ° C. for 72 hours, then taken out and left at room temperature. After that, a tensile test was performed to compare the tensile strength and elongation of the sample immersed in oil with the initial tensile strength and elongation, respectively. Those with a tensile strength change rate of ± 30% or less and an elongation change rate of ± 40% or less are regarded as acceptable “○”, and those that do not satisfy any of these, or those that do not satisfy any of these, are practical. Those that have no problem are marked with "△".

<Details of Examples and Comparative Examples and Evaluation Results>
Table 3 shows the configurations and evaluation results of Examples 1 to 15.

Table 4 shows the configurations and evaluation results of Comparative Examples 1 to 3.

As shown in Table 3, in the insulated wires of Examples 1 to 6, the thickness of each coating layer is made constant, and the composition of the flame-retardant resin composition constituting the flame-retardant layer is changed. Further, in the insulated wires of Examples 1, 7 to 10 and Comparative Example 2, the composition of each coating layer is constant and the thickness of each coating layer is changed. Further, in the insulated wires of Examples 1, 11 to 15, the thickness of each coating layer is kept constant, and the composition of the insulating resin composition constituting the insulating layer is changed.

As shown in Table 3, in Examples 1 to 6, regardless of the difference in the composition of the flame-retardant resin composition shown in Table 1, (1) DC stability, (2), (3) flame retardancy and ( 4) The oil resistance was good in each case. In addition, Example 7 showed higher flame retardancy (2) and (3) than other Examples.

In addition, Examples 1 to 13 showed higher (4) oil resistance than Examples 14 and 15.

As shown in Table 4, in Comparative Example 1, (1) DC stability and (4) oil resistance were good, while (2) and (3) flame retardancy were poor. Further, in Comparative Example 2, (1) DC stability, (3) flame retardancy: vertical tray combustion test and (4) oil resistance were good, while (2) flame retardancy: vertical combustion test was poor. became. Further, in Comparative Example 3, (2), (3) flame retardancy and (4) oil resistance were good, while (1) DC stability was poor.

<Summary of Examples and Comparative Examples>
From the results of Examples and Comparative Examples, it was shown that according to the present invention, the insulated wire 10 having a hue other than black can be provided with flame retardancy and insulating property. Specifically, it is a non-halogen insulated wire, and as shown in FIG. 1, carbon black is contained in the flame-retardant resin composition constituting the first flame-retardant layer 11a arranged on the outermost side of the coating layer 2. Even if this is not the case, the insulated wire 10 was able to pass the flame retardancy test by setting the volume ratio of two or more flame retardant layers 11 among the plurality of coating layers to 80% or more. .. Then, by setting the volume resistivity of the insulating resin composition constituting each of the one or more insulating layers 12 to 1 × 10 ¹⁵ Ω · cm or more, the insulated wire 10 can pass the DC stability test. It was.

In particular, as shown in Examples 1 to 15, the flame-retardant resin composition constituting the first flame-retardant layer 11a arranged on the outermost side contains a pigment other than black and a low molecular weight component (flammable component). The insulated wire 10 was able to pass the flame retardancy test even when a color masterbatch or dry color consisting of a dispersant was included.

Further, as shown in Example 7, it was found that even more excellent flame retardancy was exhibited, especially when the volume ratio of the flame retardant layer among the plurality of coating layers was 90% or more.

Further, as shown in Examples 1 to 13, in the insulating resin composition constituting the insulating layer 12 of the insulated wire 10 shown in FIG. 1, the (IA1) melting point is 125 ° C. in 100 parts by mass of the (IA) base polymer. It was found that by containing 40 parts by mass or more of the above (more preferably 127 ° C. or higher) polyethylene, the oil resistance test was passed at a high level in addition to the DC stability test and the flame retardancy test.

On the other hand, in Comparative Example 1, since the outermost layer was not used as the flame-retardant layer (the flame-retardant layer was not formed on the outermost layer), the flame-retardant test failed. Further, in Comparative Example 2, since the volume ratio of the flame-retardant layer among the plurality of coating layers was less than 80%, the flame-retardant test failed. Further, in Comparative Example 3, since the insulating layer was not provided, the DC stability test failed.

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 Multiple coating layers 10,100 Insulated wire 11,110 Flame retardant layer 12,120 Insulated layer

Claims (13)

It has a conductor and a plurality of coating layers that are coated around the conductor.
The plurality of coating layers have two or more flame-retardant layers and one or more insulating layers having a volume resistivity higher than that of any of the two or more flame-retardant layers.
The volume resistivity of the insulating resin composition constituting each of the one or more insulating layers is 1 × 10 ¹⁵ Ω · cm or more.
The flame-retardant resin composition constituting each of the two or more flame-retardant layers contains a base polymer and a metal hydroxide, respectively.
The volume ratio of the two or more flame-retardant layers among the plurality of coating layers is 80% or more.
The first flame-retardant layer of the two or more flame-retardant layers is arranged on the outermost side of the plurality of coating layers.
An insulated electric wire that does not contain carbon black in the flame-retardant resin composition constituting the first flame-retardant layer. In the insulated wire according to claim 1,
An insulating electric wire containing a pigment other than black and a dispersant for dispersing the pigment in the flame-retardant resin composition constituting the first flame-retardant layer. In the insulated wire according to claim 1,
An insulated wire in which carbon black is contained in the flame-retardant resin composition constituting each of the flame-retardant layers other than the first flame-retardant layer among the two or more flame-retardant layers. It has a conductor and a plurality of coating layers that are coated around the conductor.
The plurality of coating layers have two or more flame-retardant layers and one or more insulating layers having a volume resistivity higher than that of any of the two or more flame-retardant layers.
The volume resistivity of the insulating resin composition constituting each of the one or more insulating layers is 1 × 10 ¹⁵ Ω · cm or more.
The flame-retardant resin composition constituting each of the two or more flame-retardant layers contains a base polymer and a metal hydroxide, respectively.
The volume ratio of the two or more flame-retardant layers among the plurality of coating layers is 80% or more.
The first flame-retardant layer of the two or more flame-retardant layers is arranged on the outermost side of the plurality of coating layers.
The amount of carbon black added to the flame-retardant resin composition constituting the first flame-retardant layer is the difficulty of forming each of the flame-retardant layers other than the first flame-retardant layer among the two or more flame-retardant layers. Insulated wire that is less than any of the carbon black additions in the flammable resin composition. In the insulated wire according to any one of claims 1 to 4,
The flame-retardant resin composition constituting each of the two or more flame-retardant layers is an insulated electric wire containing 100 parts by mass or more and 250 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 5,
The flame-retardant resin composition constituting each of the two or more flame-retardant layers is an insulating electric wire containing an ethylene-vinyl acetate copolymer and a maleic acid-modified polymer in the base polymer. In the insulated wire according to any one of claims 1 to 6,
An insulated electric wire having a volume resistivity of 1 × 10 ¹⁷ Ω · cm or more in each of the insulating resin compositions constituting each of the one or more insulating layers. In the insulated wire according to any one of claims 1 to 7,
The insulating resin composition constituting each of the one or more insulating layers is an insulated electric wire containing an antioxidant and / or a copper damage inhibitor, respectively. In the insulated wire according to any one of claims 1 to 8,
The insulating resin composition constituting each of the one or more insulating layers is an insulated electric wire containing 40 parts by mass or more of polyethylene having a melting point of 125 ° C. or higher in 100 parts by mass of the base polymer. In the insulated wire according to any one of claims 1 to 9,
An insulated wire in which each of the two or more flame-retardant layers is alternately laminated with each of the one or more insulating layers along the radial direction of the insulated wire. In the insulated wire according to any one of claims 1 to 10.
The second flame-retardant layer of the two or more flame-retardant layers is an insulated electric wire directly coated on the conductor. In the insulated wire according to any one of claims 1 to 11.
The insulating resin composition constituting each of the one or more insulating layers is a crosslinked insulated electric wire. In the insulated wire according to claim 12,
The flame-retardant resin composition constituting each of the two or more flame-retardant layers is an insulated electric wire that is crosslinked.

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