JPH10340634A - Insulated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide sufficient flame resistance, and also improve abrasion resistance and heating deformation resistance by laminating an inner layer composed of a resin composition by blending a metallic hydroxide by specific pts.wt. to specific pts.wt. of an ethylene-α-olefin copolymer and an outer layer composed of a polyester resin on an outer periphery of a conductive conductor, and setting the thickness dimension ratio of the inner layer to the outer layer to a specific value. SOLUTION: An inner layer 2 and an outer layer 3 are laminated on an outer periphery of a copper conductor 1. In this case, the inner layer 2 is composed of a resin composition by blending a metallic hydroxide by 50 to 400 pts.wt. to 100 pts.wt. of an ethylene-α-olefin copolymer, and the outer layer 3 is composed of a polyester resin, and a thickness dimension of the inner layer 2 to the outer layer 3 is set to the inner layer 2/the outer layer 3=6/4 to 9/1. An adhesive property with an outer layer resin can be improved by using a carboxylic acid denatured ethylene-α-olefin resin at the same time as an olefin type resin of the inner layer 2, and since a polyester resin is used as the outer layer 3, economical efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-layer insulated wire having excellent properties such as abrasion resistance, flame retardancy, and heat deformation resistance.

[0002]

2. Description of the Related Art For example, as an insulating covering material used for insulated wires for automobiles, from the viewpoint of appropriate flexibility and flame retardancy,
Polyvinyl chloride resin is used more often than ever. However, when this wire is incinerated and disposed of with the scrapping of vehicles, the insulation coating burns in the incinerator, generating hydrogen chloride gas, damaging the incinerator or being discharged into the atmosphere, resulting in environmental pollution. Has the problem of causing

[0003] Therefore, in recent years, electric wires using a flame-retardant resin composition containing no halogen component such as chlorine as an insulating coating material have been studied, and the structure thereof is a mixture of a polyolefin resin and a metal hydroxide. Things are common.

[0004]

However, conventional flame-retardant resin compositions of this type are inferior in flexibility and flexibility as compared with polyvinyl chloride, and have a large amount of metallic water to provide flame retardancy. Mixing the oxide has a problem that mechanical strength such as wear resistance and tensile strength is reduced.

Therefore, as shown in, for example, JP-A-6-176631, a flame-retardant olefin material containing a large amount of a flame retardant is used in the inner layer, and an olefin resin containing little or no flame retardant is contained in the outer layer. Are considered.

However, such an example has a problem that the insulated wire is easily deformed at a high temperature.

Accordingly, an object of the present invention is to provide an insulating material which does not generate harmful gas during incineration, has excellent flexibility and bendability, has sufficient flame retardancy, and has excellent wear resistance and heat deformation resistance. To provide the wires.

[0008]

The insulated wire according to the first aspect of the present invention is an insulated wire in which the outer periphery of a conductive core is covered with an insulating layer composed of an inner layer and an outer layer, wherein the inner layer is ethylene-α-.
The resin composition comprises 50 to 400 parts by weight of a metal hydroxide with respect to 100 parts by weight of the olefin copolymer, and the outer layer is made of a polyester resin. The feature is that the outer layer is 6/4 to 9/1.

The insulated wire according to the invention of claim 2 is characterized in that, in the invention of claim 1, the resin composition of the inner layer contains a carboxylic acid-modified ethylene-α-olefin resin.

The ethylene-α-olefin copolymer used in the present invention includes an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer and an ethylene-methyl methacrylate copolymer. Such an ethylene-α-olefin copolymer containing an oxygen atom in the molecule inherently has higher flame retardancy than a normal olefin resin, and thus contributes to a reduction in the amount of metal hydroxide added. Further, the reason why the ethylene-α-olefin copolymer is used for the inner layer is that the other hard resins are insufficient in flexibility and cold resistance. As the metal hydroxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like are preferable. The average particle size of these metal hydroxides is preferably from 0.1 to 5 μm from the viewpoint of dispersibility in a polymer, workability, electric wire characteristics, and the like. The objective of can be achieved. Also,
Surface treated with silane coupling agent, titanate coupling agent, fatty acid and its metal salt for the purpose of preventing aggregation of metal hydroxide, improving dispersibility in polymer and improving adhesion to polymer It is preferable to use

In the inner layer, 50 to 4 parts by weight of a metal hydroxide is added to 100 parts by weight of the ethylene-α-olefin copolymer.
When the amount was less than 50 parts by weight, the flame retardancy of the wire was insufficient, and when the amount was more than 400 parts by weight, the extrudability, flexibility, cold resistance, etc. of the wire were insufficient. .

In the present invention, a polyester resin is used for the outer layer. This is because the use of a resin other than the polyester resin results in insufficient heat deformation resistance and wear resistance. Furthermore, in order to enhance flame retardancy, hydrotalcites, silica, carbon black, zinc borate,
A flame retardant aid such as a phosphorus compound may be added, and an antioxidant, a lubricant, a dispersant, a copper damage inhibitor, a crosslinking agent, a crosslinking aid or a coloring agent may be added, The polymer may be crosslinked by various crosslinking methods.

The ratio of the thickness to the thickness of the inner layer and the outer layer is calculated as follows:
The reason why the ratio is 6/4 to 9/1 is that if the ratio is 6/4 or less, the insulated wire has insufficient flexibility, and if it is 9/1 or more, the wear resistance and the tensile strength are insufficient.

[0014]

As described above, according to the insulated wire of the first aspect of the present invention, ethylene-α containing an oxygen atom in the molecule is used.
-Since the olefin copolymer is more excellent in flame retardancy than the ordinary polyolefin resin, it is possible to enhance the flame retardancy in the inner layer.

On the other hand, since the polyester resin used for the outer layer is generally more expensive than the olefin resin, it is economically unsuitable to apply a flame-retardant prescription to the general-purpose electric wire. However, as a result of the increased flame retardancy in the inner layer, it has become possible to use a polyester resin which is more economical in the outer layer, making use of the property of being excellent in heat deformation resistance and abrasion resistance.

Further, when a carboxylic acid-modified ethylene-α-olefin resin is used in combination with the olefin resin in the inner layer as in the second aspect of the present invention, the effect of improving the adhesion to the outer layer resin is exhibited.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below.

In Examples 1 and 2 of the present invention, ethylene-
Vinyl acetate copolymer (vinyl acetate content = 20%), ethylene-ethyl acrylate copolymer (ethyl acrylate content = 25%), carboxylic acid-modified EVA, polyester resin, aluminum hydroxide, magnesium hydroxide, and flame retardant aid A resin composition was prepared by kneading silica and red phosphorus as agents in the ratios shown in Table 1.

On the other hand, as Comparative Examples 1 to 8, ethylene-vinyl acetate copolymer (vinyl acetate content = 20%), ethylene-ethyl acrylate copolymer (ethyl acrylate content = 25%), high density polyethylene (melting point = 135
° C, Shore D hardness = 63), low density polyethylene (melting point = 98 ° C, Shore D hardness = 48), linear low density polyethylene (melting point = 110 ° C, Shore D hardness = 58), modified with carboxylic acid A resin composition was prepared by kneading EVA, polyester resin, aluminum hydroxide, magnesium hydroxide, silica, and red phosphorus at the ratios shown in Tables 2 and 3.

The ethylene-vinyl acetate copolymer is Ultracene (trade name) manufactured by Tosoh Corporation, the ethylene-ethyl acrylate copolymer is Evaflex EEA (trade name) manufactured by DuPont-Mitsui Polychemicals, and high-density polyethylene is Japan. J-LEX HD (trade name) manufactured by Polyolefin,
Low-density polyethylene is JELEX LD (trade name) manufactured by Nippon Polyolefin, linear low-density polyethylene is JELEX LL (trade name) manufactured by Nippon Polyolefin, and carboxylic acid-modified EVA is ADMER (trade name) manufactured by Mitsui Petrochemical Co., polyester The resin used was Toyobo's perprene (trade name).

As shown in FIG. 1, these resin compositions were extruded on the outer periphery of a copper core wire 1 with an inner layer 2 and an outer layer 3 at the thicknesses shown in the respective tables. went. Flame retardancy: A 300 mm long wire sample is supported horizontally, and the tip of the reducing flame is applied from below the center of the sample using a Bunsen burner with a diameter of 10 mm until it burns within 30 seconds.
After gently removing the flame, the degree of combustion of the sample was determined. Abrasion resistance: At room temperature of 23 ± 5 ° C., the insulating coating surface of a 750 mm long wire sample fixed on a table is reciprocated and abraded by a blade over a length of 10 mm or more in the axial direction. When the blade is reciprocated 50 or 60 times per minute,
The number of reciprocations until the blade contacts the core conductor due to wear of the insulator is measured. Next, the sample is moved 100 mm, rotated 90 degrees clockwise, and the above measurement is repeated.
This measurement was performed a total of four times with the same sample, and the minimum value was defined as abrasion resistance. Whitening resistance: The film was gently wound several times around a cylinder having a radius of 6 mm, and the degree of whitening of the surface was visually checked in that state.

The evaluation results are shown in Tables 1 to 3.

[0023]

[Table 1]

[0024]

[Table 2]

[Table 3] First, as shown in Table 1, in Examples 1 and 2 according to the resin composition of the present invention, all of flame retardancy, heat deformation resistance, whitening resistance, and flexibility were good. Further, the abrasion resistance greatly exceeded the target value of 300 times, and characteristic values with good tensile strength and elongation were obtained.

When Examples 1 and 2 were compared, the tensile strength of Example 2 in which carboxylic acid-modified EVA was mixed into the inner layer resin was superior to the value of Example 1, but this was because It is considered that the adhesiveness between the resin and the outer layer resin was improved.

On the other hand, in Comparative Examples 1, 2, 3, and 5 in which no polyester resin was used for the outer layer, the abrasion resistance, the tensile strength, and the thermal deformation were significantly reduced.

In Comparative Example 3 in which a resin other than the ethylene-α-olefin copolymer was used for the inner layer, the flexibility required for the inner layer resin was insufficient. When the amount of the metal hydroxide in the inner layer is small as in Comparative Example 6, the electric wire has insufficient flame retardancy. When the amount of metal hydroxide in the outer layer resin is increased in order to secure flame retardancy, properties such as abrasion resistance and tensile strength are reduced (Comparative Example 5). Conversely, Comparative Example 7
When the amount of the metal hydroxide in the inner layer is too large as described above, the flame retardancy is improved, but the abrasion resistance, tensile strength, flexibility and the like are reduced. Furthermore, when the thickness dimension ratio of the inner layer and the outer layer is 4/6 or less, the flexibility of the insulated wire is insufficient (Comparative Example 4). On the other hand, when the thickness ratio is 9/1 or more, the abrasion resistance and tensile strength are low. Insufficient (Comparative Example 8).

[Brief description of the drawings]

FIG. 1 is a sectional view of an insulated wire.

[Explanation of symbols]

 1: Copper core wire (conductive core wire) 2: Inner layer 3: Outer layer

Claims (2)

[Claims] 1. An insulated wire in which an outer peripheral layer of a conductive core wire is coated with an insulating layer composed of an inner layer and an outer layer, wherein the inner layer contains 50 to 50 parts by weight of a metal hydroxide with respect to 100 parts by weight of an ethylene-α-olefin copolymer. The outer layer is made of a polyester resin, and the thickness ratio of the inner layer and the outer layer is such that the inner layer / outer layer = 6 /
An insulated wire having a ratio of 4 to 9/1. 2. The insulated wire according to claim 1, wherein the resin composition of the inner layer contains a carboxylic acid-modified ethylene-α-olefin resin.