阅读说明：本技术 树脂组合物、绝缘电线及绝缘电线的制造方法 (Resin composition, insulated wire, and method for producing insulated wire ) 是由 芦原新吾 矢崎浩贵 青山贵 于 2019-12-31 设计创作，主要内容包括：本发明提供未交联时的耐泛白性、阻燃性和柔软性优异的树脂组合物、绝缘电线及绝缘电线的制造方法。绝缘电线(10)具有导体(1)、以及被覆于导体(1)的周围的绝缘层(2)。绝缘层(2)由包含基础聚合物和阻燃剂的树脂组合物形成。上述阻燃剂由经硅烷偶联剂表面处理后的氢氧化铝、经硅烷偶联剂以外的处理剂表面处理后的氢氧化铝和/或未经表面处理的氢氧化铝来构成。上述基础聚合物包含具有极性基团的聚合物。上述树脂组合物中,相对于上述基础聚合物100质量份含有超过40质量份且80质量份以下的上述阻燃剂。上述树脂组合物在上述阻燃剂100质量份中,含有10质量份以上70质量份以下的上述经硅烷偶联剂表面处理后的氢氧化铝。(The invention provides a resin composition, an insulated wire and a method for manufacturing the insulated wire, wherein the resin composition has excellent whitening resistance, flame retardance and flexibility when not crosslinked. The insulated wire (10) has a conductor (1) and an insulating layer (2) covering the periphery of the conductor (1). The insulating layer (2) is formed from a resin composition containing a base polymer and a flame retardant. The flame retardant is composed of aluminum hydroxide surface-treated with a silane coupling agent, aluminum hydroxide surface-treated with a treating agent other than a silane coupling agent, and/or aluminum hydroxide without surface treatment. The base polymer described above contains a polymer having a polar group. The resin composition contains the flame retardant in an amount of more than 40 parts by mass and not more than 80 parts by mass per 100 parts by mass of the base polymer. The resin composition contains 10 to 70 parts by mass of the aluminum hydroxide surface-treated with the silane coupling agent per 100 parts by mass of the flame retardant.)

1. A resin composition is a resin composition comprising a base polymer and a flame retardant,

the flame retardant is composed of aluminum hydroxide subjected to surface treatment by a silane coupling agent, aluminum hydroxide subjected to surface treatment by a treating agent other than the silane coupling agent and/or aluminum hydroxide which is not subjected to surface treatment,

the base polymer comprises a polymer having polar groups,

the resin composition contains the flame retardant in an amount of more than 40 parts by mass and not more than 80 parts by mass per 100 parts by mass of the base polymer,

the resin composition contains 10 to 70 parts by mass of the aluminum hydroxide surface-treated with the silane coupling agent per 100 parts by mass of the flame retardant.

2. The resin composition according to claim 1, wherein the polymer having a polar group is an ethylene-vinyl acetate copolymer.

3. The resin composition according to claim 1 or 2, further comprising a colorant of black, yellow, white, red or green.

4. An insulated wire comprising an insulating layer formed from the resin composition according to any one of claims 1 to 3.

5. The insulated wire according to claim 4, wherein the oxygen index is 20 or more, and the tensile strength at 100% elongation is 6.0MPa or less.

6. The insulated wire according to claim 4, which is used as an in-board wiring of a distribution board or a control board, or a motor outlet.

7. An electric cable comprising a sheath layer formed from the resin composition according to any one of claims 1 to 3.

8. A method for manufacturing an insulated wire, comprising the steps of:

(a) a step of kneading the base polymer and the flame retardant to produce a resin composition;

(b) a step of extruding the resin composition so as to cover the periphery of the conductor to form an insulating layer and produce an insulated wire in an uncrosslinked state;

(c) a step of crosslinking the base polymer in the resin composition to produce a crosslinked insulated wire,

the flame retardant is composed of aluminum hydroxide subjected to surface treatment by a silane coupling agent, aluminum hydroxide subjected to surface treatment by a treating agent other than the silane coupling agent and/or aluminum hydroxide which is not subjected to surface treatment,

the base polymer comprises a polymer having polar groups,

the resin composition contains the flame retardant in an amount of more than 40 parts by mass and not more than 80 parts by mass per 100 parts by mass of the base polymer,

the resin composition contains 10 to 70 parts by mass of the aluminum hydroxide surface-treated with the silane coupling agent per 100 parts by mass of the flame retardant.

9. The method of manufacturing an insulated wire according to claim 8, comprising, after the step (b) and before the step (c), (d) a step of winding the insulated wire in an uncrosslinked state.

10. The method of manufacturing an insulated electric wire according to claim 8 or 9,

the crosslinked insulated wire has an oxygen index of 20 or more and a tensile strength at 100% elongation of 6.0MPa or less.

Technical Field

The present invention relates to a resin composition, an insulated wire, and a method for producing an insulated wire.

Background

An insulated wire (electric wire) includes a conductor and an insulating layer (covering material) provided around the conductor. The insulating layer is formed of a resin composition (electrically insulating material) mainly composed of rubber or resin. In recent years, in view of environmental problems, insulated wires (hereinafter, referred to as halogen-free insulated wires) in which an insulating layer is composed of a halogen-free resin composition containing no halogen such as fluorine, chlorine, bromine or the like which may generate a harmful gas upon combustion have been widely used. In particular, the halogen-free insulated wire is suitably used for a distribution board, an in-board wiring of a control board, a motor lead wire, and the like, which have a relatively high possibility of being in contact with a person.

Halogen-free resin compositions generally have low flame retardancy, and therefore are generally used with addition of a flame retardant. For example, patent document 1 describes an electric wire or the like in which an insulating layer is formed from a resin containing a halogen-free flame retardant such as magnesium hydroxide.

Disclosure of Invention

Problems to be solved by the invention

Here, the matters of the study by the present inventors will be explained. The method for manufacturing the insulated wire includes, for example, the steps of: the resin composition is extruded so as to cover the periphery of the conductor, thereby forming an insulating layer (hereinafter referred to as an insulating layer covering step). In general, in order to impart properties such as flexibility and heat resistance to an insulating layer of an insulated wire, a crosslinking step of chemically bonding molecules included in a resin composition is required. As a method for producing the insulated wire, there are considered 2 methods of (1) carrying out an in-line crosslinking step after the insulating layer coating step, and carrying out in-line crosslinking in which the insulated wire is wound around a drum, (2) carrying out post-crosslinking in which the insulating layer is wound around the drum in an uncrosslinked state after the insulating layer coating step, and then crosslinked in another step.

(1) In the case of in-line crosslinking, a method of crosslinking under high temperature and high pressure conditions by filling a crosslinking tube connected to an extruder with high pressure steam is generally employed. Since the high-pressure atmosphere is used, it is desirable to provide a spacer between the conductor and the insulating layer in order to prevent the resin composition from entering the conductor. On the other hand, in the case of (2) post-crosslinking, since a method of crosslinking without requiring high pressure, for example, irradiation with electron beams is generally employed, the resin composition is less likely to intrude into the conductor, and a spacer is not required. Therefore, from the viewpoint of reducing the production cost of the insulated wire and improving the efficiency of the wiring operation, (2) postcrosslinking capable of producing a so-called separator-less insulated wire is preferable.

Examples of the crosslinking method used for the post-crosslinking in (2) include an electron beam irradiation method and a silane crosslinking method. In particular, the electron beam irradiation method is preferable because it can be applied to crosslinking of almost all resin compositions and the compounding composition of the resin compositions can be relatively simplified.

However, the present inventors have confirmed the following problems with respect to (2) postcrosslinking. (2) In the case of the electron beam irradiation method in the post-crosslinking, generally, after the insulating layer coating step, the insulated wire is once wound around a drum or the like, and then the insulated wire is pulled out from the drum in another step, and the insulated wire is irradiated with an electron beam. At this time, the surface of the non-crosslinked insulated wire is rubbed against a jig such as a drum (see a drum 29 shown in fig. 2 described later) or a pulley for unwinding the insulated wire, or the wires rub against each other, whereby the wires are damaged or whitened. As a result, the problem arises that the appearance of the insulated wire is deteriorated.

This problem occurs not only in the electron beam irradiation method but also in the case of using the silane crosslinking method. This is because, in the case of the silane crosslinking method, the uncrosslinked insulated wire is wound around a drum or the like, and then crosslinking is performed by moisture in the air, and therefore, it is common in the point that the uncrosslinked insulated wire is wound around a drum or the like.

In order to solve such problems, it is necessary to study the composition of the resin composition, but at the same time, it is not essential to secure flame retardancy and flexibility of an insulating layer of an insulated wire required for applications such as in-board wiring of a distribution board and a control panel, and motor lead wires.

The present invention has been made in view of the above problems, and an object thereof is to provide a resin composition and an insulated wire which are excellent in whitening resistance, flame retardancy, and flexibility when not crosslinked.

Means for solving the problems

The invention disclosed in the present application will be described below, simply explaining an outline of a representative example.

[1] The resin composition includes a base polymer and a flame retardant. The flame retardant is composed of aluminum hydroxide surface-treated with a silane coupling agent, aluminum hydroxide surface-treated with a treating agent other than a silane coupling agent, and/or aluminum hydroxide without surface treatment. The base polymer described above contains a polymer having a polar group. The resin composition contains the flame retardant in an amount of more than 40 parts by mass and not more than 80 parts by mass per 100 parts by mass of the base polymer. The resin composition contains 10 to 70 parts by mass of the aluminum hydroxide surface-treated with the silane coupling agent per 100 parts by mass of the flame retardant.

[2] The resin composition according to [1], wherein the polymer having a polar group is an ethylene-vinyl acetate copolymer.

[3] The resin composition according to [1] or [2], further comprising a colorant of black, yellow, white, red or green.

[4] An insulated wire comprising an insulating layer formed from the resin composition according to any one of [1] to [3 ].

[5] The insulated wire according to [4], which has an oxygen index of 20 or more and a tensile strength at 100% elongation of 6.0MPa or less.

[6] The insulated wire according to [4], which is used as an in-board wiring of a distribution board or a control board, or a motor lead-out wire.

[7] An electric cable comprising a sheath layer formed from the resin composition according to any one of [1] to [3 ].

[8] The method for manufacturing an insulated wire comprises the following steps: (a) a step of kneading the base polymer and the flame retardant to produce a resin composition; (b) extruding the resin composition to cover the periphery of the conductor to form an insulating layer, thereby producing an insulated wire in an uncrosslinked state; (c) and a step of crosslinking the base polymer in the resin composition to produce a crosslinked insulated wire. The flame retardant is composed of aluminum hydroxide surface-treated with a silane coupling agent, aluminum hydroxide surface-treated with a treating agent other than a silane coupling agent, and/or aluminum hydroxide without surface treatment. The base polymer described above contains a polymer having a polar group. The resin composition contains the flame retardant in an amount of more than 40 parts by mass and not more than 80 parts by mass per 100 parts by mass of the base polymer. The resin composition contains 10 to 70 parts by mass of the aluminum hydroxide surface-treated with the silane coupling agent per 100 parts by mass of the flame retardant.

[9] The method of manufacturing an insulated wire according to [8], which comprises (d) a step of winding the insulated wire in an uncrosslinked state after the step (b) and before the step (c).

[10] The method of producing an insulated wire according to [8] or [9], wherein the crosslinked insulated wire has an oxygen index of 20 or more and a tensile strength at 100% elongation of 6.0MPa or less.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a resin composition and an insulated wire excellent in whitening resistance, flame retardancy, and flexibility when not crosslinked can be provided.

Drawings

Fig. 1 is a cross-sectional view showing a structure of an insulated wire according to an embodiment.

Fig. 2 is a schematic view showing an extrusion coating apparatus for manufacturing an insulated wire according to an embodiment.

Description of the symbols

1 conductor, 2 insulating layers, 5 and 10 insulated wires, 21 extrusion coating device, 22 hopper, 23 screw, 24 perforated plate, 25 head, 26 neck, 27 die head, 28 barrel and 29 drum

Detailed Description

(embodiment mode)

< constitution of resin composition >

One embodiment of the present invention relates to a resin composition (halogen-free resin composition, flame-retardant resin composition) comprising (a) a base polymer and (B) a flame retardant. Further, the (a) base polymer contains (a1) a polymer having a polar group. (A1) Examples of the polymer having a polar group include an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, and the like, and an ethylene-vinyl acetate copolymer is preferable.

(A1) The polymer having a polar group may be a single ethylene-vinyl acetate copolymer, but as shown in examples described later, it is more preferable to mix two or more kinds of ethylene-vinyl acetate copolymers. Here, if the vinyl acetate content (VA amount) in the ethylene-vinyl acetate copolymer becomes large, the glass transition temperature increases and the low-temperature characteristics deteriorate. On the other hand, if the vinyl acetate content in the ethylene-vinyl acetate copolymer is reduced, the polarity is reduced and the fuel resistance is reduced. Therefore, by including two or more ethylene-vinyl acetate copolymers having different vinyl acetate content, a resin composition having an excellent balance between low-temperature characteristics and fuel resistance characteristics can be produced. In addition, in examples described later, an ethylene-vinyl acetate copolymer having a vinyl acetate content (VA amount) of 15 mass% and an ethylene-vinyl acetate copolymer having a vinyl acetate content (VA amount) of 28 mass% were used.

The base polymer (a) contains, in addition to the polymer (a1) having a polar group, (a2) other polymers (a2) examples of the other polymers include a mixture of at least 1 or more ethylene copolymers selected from polyethylene, polypropylene, an ethylene- α -olefin copolymer, a terpolymer to which a monomer is further added, an ethylene-propylene-diene copolymer, and a modified product thereof (for example, a product obtained by copolymerizing or graft-polymerizing a silane compound, or a maleic acid modified product).

In examples described later, an ethylene- α -olefin copolymer is used as the other polymer (a 2). examples of the ethylene- α -olefin copolymer include an ethylene-propylene copolymer, an ethylene-butene copolymer, an ethylene-pentene copolymer, an ethylene-hexene copolymer, an ethylene-heptene copolymer, an ethylene-octene copolymer, and the like, and the other polymer is preferably an ethylene-butene copolymer.

The flame retardant (B) of the present embodiment is composed of (B1) aluminum hydroxide surface-treated with a silane coupling agent, (B2) aluminum hydroxide surface-treated with a treating agent other than a silane coupling agent, and/or (B3) aluminum hydroxide without surface treatment.

The silane coupling agent is an organosilicon compound having an unsaturated bonding group and a hydrolyzable silane group. Examples of the silane coupling agent include gamma-methacryloxypropyltrimethoxysilane, n-hexadecyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, gamma-ureidopropyltriethoxysilane, gamma-dibutylaminopropyltrimethoxysilane and gamma-diallylaminopropyltrimethoxysilane. The aluminum hydroxide surface-treated with the silane coupling agent according to the present embodiment can be produced, for example, by spraying or impregnating a solution of the silane coupling agent into aluminum hydroxide and then drying the aluminum hydroxide.

Examples of the treating agent other than the silane coupling agent include fatty acids such as stearic acid, fatty acid metal salts such as calcium stearate, and titanate-based coupling agents. These treating agents may be used in combination of a plurality of components.

The resin composition of the present embodiment may contain, in addition to the base polymer (a) and the flame retardant (B), a crosslinking assistant (C), an antioxidant (D), a copper harm inhibitor (E), a lubricant (F), a colorant (G), and the like, as required. Examples of the crosslinking assistant (C) include trimethylolpropane trimethacrylate (TMPT), triallylisocyanurate, triallylcyanurate, N' -m-phenylene bismaleimide, ethylene glycol dimethacrylate, zinc acrylate, and zinc methacrylate. Examples of the antioxidant (D) include a phenol-based antioxidant, a sulfur-based antioxidant, a phenol/thioester-based antioxidant, an amine-based antioxidant, and a phosphite-based antioxidant. Examples of the copper harm inhibitor (E) include hydrazides such as N ' 1, N ' 12-bis (2-hydroxybenzoyl) dodecanedihydrazide, N ' -bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl ] hydrazine, and isophthalic acid bis (2-phenoxypropionylhydrazide), 2-hydroxy-N-1H-1, 2, 4-triazol-3-ylbenzamide, and alcohol carboxylates as heavy metal deactivators. Examples of the lubricant (F) include fatty acid amide (amide), zinc stearate, silicone, hydrocarbon, ester, alcohol, and metal soap. Examples of the colorant (G) include carbon black, inorganic pigments, organic pigments, and dyes.

As shown in examples described below, the resin composition of the present embodiment contains the flame retardant (B) in an amount of more than 40 parts by mass and not more than 80 parts by mass per 100 parts by mass of the base polymer (a). If the amount of the flame retardant (B) added is 40 parts by mass or less based on 100 parts by mass of the base polymer (A), sufficient flame retardancy cannot be obtained. On the other hand, if the amount of the flame retardant (B) added is more than 80 parts by mass relative to 100 parts by mass of the base polymer (A), flexibility is lowered.

As shown in examples described later, the resin composition of the present embodiment contains 10 to 70 parts by mass of (B1) aluminum hydroxide surface-treated with a silane coupling agent in 100 parts by mass of (B) a flame retardant. If the content of aluminum hydroxide surface-treated with a silane coupling agent in (B1) 100 parts by mass of the flame retardant (B) is less than 10 parts by mass, the whitening resistance when uncrosslinked is lowered. On the other hand, if the content of the aluminum hydroxide surface-treated with the silane coupling agent (B1) in 100 parts by mass of the flame retardant (B) exceeds 70 parts by mass, flexibility is lowered. The resin composition according to one embodiment of the present invention is preferably a halogen-free resin composition containing no halogen.

< constitution of insulated wire >

Fig. 1 is a cross-sectional view showing an insulated wire (electric wire) according to an embodiment of the present invention. As shown in fig. 1, an insulated wire 10 according to the present embodiment includes a conductor 1 and an insulating layer 2 covering the periphery of the conductor 1. The insulating layer 2 is formed of the resin composition of the present embodiment.

As the conductor 1, besides a metal wire generally used, for example, a copper wire or a copper alloy wire, an aluminum wire, a gold wire, a silver wire, or the like can be used. As the conductor 1, a conductor plated with a metal such as tin or nickel around a metal wire may be used. Further, as the conductor 1, a twisted conductor obtained by twisting metal wires can be used.

As shown in fig. 1, in the insulated wire 10 of the present embodiment, it is preferable that no spacer (no spacer) is provided between the conductor 1 and the insulating layer 2 from the viewpoint of reducing the manufacturing cost and improving the efficiency of the wiring operation, but the insulated wire is not limited thereto.

In the case of the cable of the present embodiment, the sheath layer is provided on the outer periphery of the insulating layer. In this case, from the viewpoint of preventing damage and whitening in the cable production process, it is preferable that at least the sheath layer as the outermost layer (outermost layer) is formed of the resin composition of the present embodiment. In this case, the composition of the insulating layer is not particularly limited, but the insulating layer is preferably composed of the resin composition of the present embodiment.

The insulated wire 10 of the present embodiment can be applied to all uses and sizes, and can be used as each wire for railway vehicles, automobiles, in-tray wiring, in-facility wiring, and electric power. In particular, the insulated wire 10 of the present embodiment is effective for use as an in-board wiring of a distribution board or a control panel, or as a motor lead wire, and is also effective for use in which wiring operability in a narrow place (narrow-place wiring performance) is required and for a wire with a high possibility of direct contact with a person.

< method for manufacturing insulated wire >

First, an apparatus for manufacturing an insulated wire according to the present embodiment will be described. Fig. 2 is a schematic view showing an extrusion coating apparatus for manufacturing an insulated wire according to an embodiment of the present invention.

The extrusion coating device 21 according to the present embodiment is, for example, a single screw extruder (L/D is 20) having a screw diameter of 65mm, the extrusion coating device 21 includes a hopper 22 into which pellets of a resin composition are charged, a cylinder 28 for heating the resin composition, a screw 23 for extruding the resin composition in the cylinder 28, and a breaker plate 24 for regulating the flow of the resin composition and increasing back pressure to improve a kneading state, and further, the extrusion coating device 21 includes a head 25 for coating the resin composition around a conductor 1, a neck (tack) 26 for connecting the cylinder 28 and the head 25, and a die 27 for determining the diameter of an electric wire, the screw 23 has a full-flight shape, and the cylinder 28 is divided into 5 cylinders, and hereinafter, referred to as cylinder 1 to cylinder 5 (not shown, see table 1) in order from the hopper 22 side.

The electron beam irradiation device according to the present embodiment includes an electron beam irradiation unit and a pulley for guiding an insulated wire (hereinafter, the electron beam irradiation device is not shown).

Next, a method for manufacturing the insulated wire 10 according to the present embodiment will be described. First, the base polymer (a) and the flame retardant (B) are kneaded by, for example, a kneader to produce, for example, a resin composition (composite) molded into a pellet shape (kneading step).

Next, pellets of, for example, a resin composition are charged into a hopper 22 by an extrusion coating apparatus 21 shown in fig. 2. Then, the resin composition is extruded so as to cover the periphery of the conductor 1, thereby forming the insulating layer 2 having a predetermined thickness (insulating layer covering step). By doing so, an uncrosslinked insulated wire 5 can be produced. The prepared non-crosslinked insulated wire 5 is temporarily stored in a state of being wound around a drum 29.

Next, the non-crosslinked insulated wire 5 is pulled out from the drum 29 by the electron beam irradiation device, guided by a pulley, and introduced into the electron beam irradiation section. Then, the electron beam irradiation unit irradiates the non-crosslinked insulated wire 5 with an electron beam (crosslinking step). By doing so, the base polymer (a) in the resin composition constituting the insulating layer 2 of the non-crosslinked insulated wire 5 can be crosslinked, and a crosslinked insulated wire 10 can be produced. The crosslinked insulated wire 10 is guided to, for example, a pulley and wound on a drum. Through the above steps, the insulated wire 10 of the present embodiment can be manufactured.

In addition, the insulated wire 10 of the present embodiment has been described by taking as an example the case where crosslinking is performed by the electron beam irradiation method, but is not limited thereto. For example, the chemical crosslinking method may be a chemical crosslinking method in which a crosslinking agent is added to a resin composition in advance, and crosslinking is performed by heat treatment or the like after the production of the uncrosslinked insulated electric wire 5 to produce the crosslinked insulated electric wire 10. That is, the resin composition of the present embodiment can be suitably used as the following materials: the material of the insulating layer (sheath layer in the cable) of the insulated wire is manufactured by a manufacturing process including a process of winding the uncrosslinked insulated wire 5 around a drum or the like before crosslinking to apply an external force such as bending or friction to the uncrosslinked insulated wire 5.

The kneading device used for producing the resin composition of the present embodiment is not limited to a kneading kneader, and for example, a known kneading device such as a batch kneader such as a banbury mixer, or a continuous kneader such as a twin-screw extruder can be used.

< features and effects of the present embodiment >

One embodiment of the present invention relates to a resin composition comprising (a) a base polymer and (B) a flame retardant. And (a) the base polymer comprises (a1) a polymer having a polar group. The flame retardant (B) of the present embodiment is composed of (B1) aluminum hydroxide surface-treated with a silane coupling agent, (B2) aluminum hydroxide surface-treated with a treating agent other than a silane coupling agent, and/or (B3) aluminum hydroxide without surface treatment. The resin composition of the present embodiment contains the flame retardant (B) in an amount of more than 40 parts by mass and 80 parts by mass or less based on 100 parts by mass of the base polymer (a). The resin composition of the present embodiment contains 10 to 70 parts by mass of (B1) aluminum hydroxide surface-treated with a silane coupling agent, per 100 parts by mass of (B) the flame retardant.

As shown in fig. 1, an insulated wire 10 according to an embodiment of the present invention includes a conductor 1 and an insulating layer 2 covering the periphery of the conductor 1, and the insulating layer 2 is formed of the resin composition of the present embodiment.

Further, the method for manufacturing an insulated wire according to the present embodiment includes the steps of: (a) a step of kneading a base polymer and a flame retardant to produce a resin composition, (b) a step of extruding the resin composition so as to cover the periphery of a conductor to form an insulating layer and produce an insulated wire in an uncrosslinked state, and (c) a step of crosslinking the base polymer in the resin composition to produce a crosslinked insulated wire. The resin composition produced in the step (a) is the resin composition of the present embodiment described above.

In the present embodiment, by adopting the above-described configuration and steps, it is possible to provide a resin composition and an insulated wire which are excellent in whitening resistance, flame retardancy, and flexibility when not crosslinked. The reason for this will be described below in detail.

As described above, if post-crosslinking is employed without providing a spacer between the conductor and the insulating layer, the non-crosslinked insulated wire needs to be wound around a drum or the like, and the wire is damaged or whitened at this time. As a result, the appearance of the insulated wire is deteriorated. Here, the whitening phenomenon is considered to occur when an external force such as bending or friction is applied to the material, and peeling occurs at the interface between the resin as a base (base polymer) and the filler (e.g., flame retardant) dispersed in the resin. Therefore, it is considered that the adhesion between the resin and the filler is important for suppressing the whitening phenomenon.

In this regard, the resin composition according to one embodiment of the present invention includes (a1) a polymer having a polar group in (a) a base polymer, and (B) aluminum hydroxide surface-treated with a silane coupling agent in (B1) a flame retardant. (B1) The aluminum hydroxide surface-treated with the silane coupling agent has high affinity with the polymer having a polar group (a1), and therefore, the adhesion between the base polymer (a) and the flame retardant (B) can be improved. As a result, the insulated wire of the present embodiment has the insulating layer formed of the resin composition, and therefore, even when the surface of the non-crosslinked insulated wire 5 is rubbed against a jig such as a drum 29 and a pulley for unwinding the insulated wire 5 shown in fig. 2, or the insulated wires 5 are rubbed against each other, the wires can be prevented from being damaged or whitened.

As described above, if the aluminum hydroxide surface-treated with the silane coupling agent (B1) is used alone, the affinity with the polymer having a polar group (a1) is too high, and thus the flexibility of the insulating layer as an insulated wire is lowered. Therefore, in the present embodiment, the flame retardant (B) is configured to contain not only (B1) aluminum hydroxide surface-treated with a silane coupling agent but also (B2) aluminum hydroxide surface-treated with a treating agent other than a silane coupling agent and/or (B3) aluminum hydroxide without surface treatment. By doing so, the resin composition of the present embodiment can ensure flame retardancy and flexibility as an insulating layer of an insulated wire, and can improve adhesion between the base polymer (a) and the flame retardant (B).

As described above, the resin composition and the insulated wire according to the present embodiment can ensure flame retardancy and flexibility of the insulating layer of the insulated wire required for applications such as distribution boards and in-board wiring of control boards, motor lead wires, and the like, while ensuring whitening resistance when not crosslinked.

(examples)

The present invention will be described in further detail below with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 12 and comparative examples 1 to 7 shown below are examples of insulated wires having the same configuration as the insulated wire 10 shown in fig. 1, and each corresponds to an example in which the formulation of the resin composition constituting the insulating layer 2 is changed. As the conductor 1, a tin copper-plated twisted wire (cross-sectional area 2 mm) was used²). In addition, the insulating layer 2 was formed of resin compositions having the formulations shown in table 2 and table 4, respectively, in examples 1 to 12, and resin compositions having the formulations shown in table 3, respectively, in comparative examples 1 to 7.

< raw materials of examples 1 to 12 and comparative examples 1 to 7 >