JP2000299023A - Recyclable power cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power cable with high heat-resistance, a high extrusion molding property, high water-tree resistance, and having an insulator with a high peeling-off property, high recovering workability, and high recyclability. SOLUTION: A power cable has a conductor 1, an inner semi-conductive layer 2b, and an insulator 3b, and the inner semi-conductive layer 2b is made of high molecular weight ethylene-vinyl acetate copolymer, semi-conductive carbon black, etc., and the insulator 3b is made of straight-chain polyethylene having a melt tension of 3 g or more and a melting point of 120 deg. or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to power cables, and more particularly to recyclable power cables.

[0002]

2. Description of the Related Art A typical example of a conventional power cable of this type is an internal semiconductive layer formed by extrusion-coating a resin composition in which a semiconductive material such as carbon black is highly mixed with a plastic on a conductor. And a power cable on which a crosslinked polyethylene insulator is formed (FIG. 1).
reference).

[0003] However, when attempting to recycle such a conventional power cable, the crosslinked polyethylene used for the insulator has no thermoplasticity, and therefore cannot be recycled as it is even if separated and collected. There was no way. Moreover, in the conventional power cable structure, the semiconductive material contained in the inner semiconductive layer inevitably adheres to the insulator, so that only the insulator is separated and recovered from the constituent components of the inner semiconductive layer. From this point, recycling as an insulator material (material recycling) was impossible.

[0004]

SUMMARY OF THE INVENTION The present invention has been devised to effectively solve the above problems.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power cable having a frist internal semiconductive layer which can be easily peeled off with an insulator by human power, shortens the time required for recovery, and has high recyclability. Is to provide.

Another object of the present invention is to provide an internal semiconductive layer having high recyclability, and to reliably recover only the insulator without causing the semiconductive material to adhere to the insulator material. An object of the present invention is to provide a highly recyclable (material-recyclable) power cable that can be reused as an insulator without lowering the grade.

[0007]

To achieve the above object, the present invention provides a power cable having a conductor, an inner semiconductive layer on the conductor, and an insulator on the inner semiconductive layer.
The inner semiconductive layer has a number average molecular weight of 3 × 10 ⁴ or more, or a weight average molecular weight of 3 × 10 ⁵ or more and a melting point of 60 to
A semi-conductive carbon black having a volume resistivity of not more than 5000 Ω · cm at room temperature with respect to 100 parts by weight of the ethylene-vinyl acetate copolymer and the ethylene-vinyl acetate copolymer at 80 ° C. An insulating resin composition comprising a conductive resin composition, wherein the insulator has a melt tension of 3 g or more, and a non-crosslinked type heat-resistant linear polyethylene having a melting point of 120 ° C. or more. It is characterized by comprising. Thereby, for example, by introducing the semiconductive resin composition and the insulating resin composition into the process of extrusion molding of a power cable, a frist type internal semiconductor layer on a conductor and an object thereover can be obtained. A recyclable power cable having an insulator with features is obtained.

[0008] The semiconductive resin composition of the present invention, in addition to the ethylene-vinyl acetate copolymer and the semiconductive carbon black, may be used in an amount of 99 to 50 parts by weight based on the ethylene-vinyl acetate copolymer. It is preferable that 1 to 50 parts by weight of a polyolefin having a melting point of 120 ° C. or more and one or more polyolefins selected from high-density polyethylene, linear polyethylene, and polypropylene are contained.

Further, the above semiconductive resin composition of the present invention comprises:
In addition to the ethylene-vinyl acetate copolymer, the semiconductive carbon and the polyolefin having a melting point of 120 ° C. or more, the ethylene-vinyl acetate copolymer and the melting point of 1
It is further preferable to add a hydrocarbon wax having a volatilization amount of less than 2% at 200 ° C in a ratio of 1 to 20 parts by weight based on 100 parts by weight of the total amount of the polyolefin of 20 ° C or more.

Further, the above-mentioned insulating resin composition of the present invention may further comprise (1) a non-crosslinked, heat-resistant linear polyethylene having a melting point of 120 ° C. or more, and (2) a mixture of the above-mentioned linear polyethylene. High-pressure radically polymerized polyethylene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene methacrylate copolymer, ethylene methyl methacrylate copolymer, ethylene propylene rubber, ethylene having a melt tension of 3 g or more in the blend. It is more preferable that one or more selected from ethylene copolymers such as butene-1 copolymer and ethylene octene rubber can be contained.

The inventor of the present invention generally devises a semiconductive resin composition to increase the difference in solubility parameters in order to facilitate separation between the semiconductive layer and the insulator, that is, ethylene-acetic acid. As a result of intensive studies on the point that increasing the concentration of vinyl acetate in the vinyl copolymer was said to be effective, it was confirmed that simply increasing the concentration of vinyl acetate was not sufficient. I thought that the releasability might be improved by suppressing the molecular diffusion of the polymer at the interface with the semiconductive layer, and as a result of repeated studies, it was found that the ethylene-vinyl acetate copolymer had a high molecular weight, It has been found that the application of the synthesized ethylene-vinyl acetate copolymer having a large molecular weight to the synthesized product can significantly improve the releasability without extremely increasing the concentration of vinyl acetate. And it completed the present invention.

In the present invention, the ethylene-vinyl acetate copolymer as a component of the semiconductive resin composition includes:
High molecular weight copolymer, ie 3 determined by osmometry
An ethylene-vinyl acetate copolymer having a weight average molecular weight of 3 × 10 ⁴ or more measured by a light scattering method of 3 × 10 ⁴ or more is used. It is possible to improve the peelability between the layer and the insulator. This is due not only to the increase in the difference in the solubility parameter due to the vinyl acetate component, but also to the effect of suppressing the molecular diffusion of the polymer at the interface between the insulator and the semiconductive layer. It is considered that the peelability is improved. The concentration of vinyl acetate in the ethylene-vinyl acetate copolymer is such that the melting point obtained from the crystal melting peak of a differential scanning calorimeter (DSC) is 60 to 80 ° C.
Here, the reason why the melting point is 60 to 80 ° C. is that the melting point is 60 ° C.
If the melting point is less than 80 ° C., the molecular weight will be increased if the melting point exceeds 80 ° C. This is because, even if it is defined as follows, the peel strength becomes high and the peelability becomes insufficient.

In the present invention, examples of the high molecular weight ethylene-vinyl acetate copolymer as described above include those selected from high molecular weight copolymers synthesized by a multistage polymerization technique.

[0014] The semiconductive resin composition of the present invention comprises, in addition to the vinyl acetate copolymer and the semiconductive carbon black, 1 to 50 parts by weight based on 99 to 50 parts by weight of the vinyl acetate copolymer. It is preferable to include a polyolefin having a melting point of 120 ° C. or higher and a polyolefin composed of one or more selected from high-density polyethylene, linear polyethylene, and polypropylene. This is because the heating deformation rate during actual use of the cable can be further reduced. Here, the reason why the blending amount of the polyolefin having a melting point of 120 ° C. or higher was 1 to 50 parts by weight,
If the amount exceeds the specified amount, the peel strength between the insulator and the semiconductive layer becomes too high, and peeling becomes difficult.

In the present invention, the ethylene-vinyl acetate copolymer as a semiconductive resin component has a melting point of 120 ° C.
In addition to the above polyolefin, the volatilization amount at 200 ° C is 2% based on 100 parts by weight of the ethylene-vinyl acetate polymer and the polyolefin having a melting point of 120 ° C or higher.
It is more preferable to mix 1 to 20 parts by weight of a hydrocarbon wax having less than 10 parts by weight, because the viscosity of the semiconductive resin composition can be reduced and the processability can be improved. However, by thermogravimetric analysis (TGA),
When the weight loss (volatilization) measured at a temperature of 5 ° C./min from normal temperature to 200 ° C. is 2% or more, foaming occurs during extrusion coating, and voids are formed inside the semiconductive layer. This is not preferable because there is a problem that separation occurs at the interface with the insulator.

In the present invention, the hydrocarbon wax as described above includes a high molecular weight polyethylene having a molecular weight of 10,000 or less, a low molecular weight high density polyethylene, a medium density polyethylene, a low density polyethylene, an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate. Examples include those selected from ethylene-based polymers such as copolymers and polypropylene.

In the present invention, the melt tension as a component of the insulating resin composition is 3 g (measured at 190 ° C.)
As described above, as a linear polyethylene having a melting point of 120 ° C. or more, a Ziegler-based multi-site catalyst or a single-site catalyst called a metallocene catalyst having a melt tension (3 g or more) and a melting point (120 ° C.) as described above is used. It includes two-stage polymerized polyethylene or polyethylene having a wide molecular weight distribution polymerized using a chromium-based catalyst. Here, the melt tension is 3 g (19
The reason for selecting and using a linear polyethylene having a melting point of 120 ° C. or higher (measured at 0 ° C.) or higher is to improve dielectric breakdown strength and water-resistant tree characteristics. In particular, by setting the melt tension to 3 g or more, not only deformation after extrusion molding can be suppressed, but also the generation of microvoids when the resin crystallizes and shrinks in the cooling process can be suppressed. This is because the water-resistant tree characteristics can be improved. In particular, by setting the melting point to 120 ° C. or higher, the heating deformation rate at 120 ° C. in the test method specified in JIS C3005 can be reduced. The melting point specified here is determined by using a differential scanning calorimeter (DSC).
It is an endothermic peak temperature measured at a temperature rise rate of ° C./min.

A preferred group of insulating resin compositions according to the present invention is a resin blended with a linear polyethylene having a melting point of 120 ° C. or more and an ethylene copolymer and having a melt tension of 3 g or more. It is an insulating resin composition mainly composed of a material. Such an insulating resin composition is obtained by blending a linear polyethylene having a melt tension of 3 g or more and a melting point of 120 ° C. or more, or another linear polyethylene having a melting point of 120 ° C. or more and an ethylene copolymer. Can be done. Here, as the ethylene copolymer to be blended with the linear polyethylene having a melting point of 120 ° C. or more, a high-pressure radical copolymer,
Selected from ethylene copolymers such as ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene methacrylate copolymer, ethylene methyl methacrylate copolymer, ethylene propylene rubber, ethylene butene-1 copolymer, and ethylene octene rubber. One or two
Or more, and the melt tension of the blend is 3
It is preferable to blend them in such a ratio as to obtain g or more. The reason is that this improves the water tree resistance.

The polymer which can be used in combination with the above-mentioned ethylene copolymer includes hydrogenated styrene-butadiene rubber, hydrogenated styrene-butadiene styrene rubber, and a mixture thereof.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in comparison with a conventional power cable with reference to the accompanying drawings.

FIG. 4 is a schematic sectional view of an embodiment of a power cable according to the present invention. FIGS. 5 and 6 show a power cable shown in FIG. 4 and a conductor and an inner semiconductive layer respectively taken out successively. It is a schematic explanatory view of the state where it did. FIGS. 1, 2 and 3 are schematic explanatory views of a power cable according to the prior art, and correspond to FIGS. 4, 5 and 6, respectively. FIG. 7 is a schematic explanatory view of another embodiment of the power cable according to the present invention.

In the example of the power cable according to the present invention shown in FIG. 4, a conductor 1, an inner semiconductive layer (a frist type semiconductive resin composition) 2b extruded on the conductor 1,
It is composed of an insulator (non-crosslinked type heat-resistant polyethylene) 3b formed on the inner semiconductive 2b and a PVC sheath 4 thereon. As shown in FIG. 5, the conductor 1 is taken out from the power cable shown in FIG. 4, and then the inner semiconductive layer (frist type semiconductive resin composition) 2b is taken out as shown in FIG. No adhesion of the internal semiconductive layer (semiconductive resin composition) 2b inside the (non-crosslinked type heat resistant polyethylene) 3b is observed at all.

On the other hand, the conductor 1 is taken out from the power cable according to the prior art as shown in FIG. 1 (FIG. 2).
Next, the inner semiconductive layer (semiconductive resin composition) 2 is placed inside the crosslinked polyethylene insulator 3a in a state where the inner semiconductive layer (Frist type semiconductive resin composition) 2a is taken out.
Part of a adheres and remains.

In another example of the power cable according to the present invention shown in FIG. 7, a conductor 1, an inner semiconductive layer (Frist type semiconductive resin composition) 2b, and an insulator (non-crosslinked type heat resistant polyethylene) 3), outer semiconductive layer (Frist type semiconductive resin composition) 5 and PVC sheath 4
Constitutes a power cable.

A preferred embodiment of the present invention relates to a power cable in which an internal semiconductive layer composed of a semiconductive resin composition as described above and an insulator composed of a non-crosslinked resin as described above are combined. Then, it is illustrated in the following examples in comparison with a comparative example.

[0026]

EXAMPLES Hereinafter, specific examples of the present invention will be described in comparison with comparative examples.

(Embodiment) As shown in FIG. 4, a frist-type internal semiconductive layer 2b is formed on a conductor 1 and a non-crosslinkable heat-resistant polyethylene insulator capable of material recycling is formed on the conductor 1 as shown in FIG. 3b, and a power cable comprising a PVC sheath 4 was manufactured.

Here, the conductor cross-sectional area is 60 mm ² ,
Frist internal semiconductive layer thickness 0.7 mm (FIG. 6: t1),
The insulator thickness was 4.5 mm (FIG. 6: t2).

As the semiconductive resin composition for the internal semiconductive layer, those having the composition components shown in groups C, D and E in Table 3 were used. , Table 1
Of the composition components shown in Group A and Group B in Table 5-9
And used in combination.

Comparative Example A power cable for comparison was extruded according to the above-described example. As the semiconductive resin composition for the internal semiconductor layer, those having composition components shown in Group F in Table 4 are shown in Groups A and B in Table 1 as insulating resin compositions for insulators. Used in combination with

The comparative examples (1 to 5) in Table 2 show the components (and the evaluation results) of the reference comparative insulating composition in the preliminary experiment stage.

The above-mentioned power cable and the like are used as samples for the following evaluation, and the evaluation results are shown in the corresponding tables.

A brief description of the resin composition will be given below.

(1) Group A: As a linear polyethylene having a melt tension of 3 g or more and a melting point of 120 ° C. or more, a linear polyethylene obtained by two-stage polymerization using a Ziegler catalyst (density d = 0.935 g / cm ³ , Melt index (M
I) = 0.8, melting point = 126 ° C., melt tension = 5
g), two-stage polymerized linear polyethylene using a single-site catalyst (d = 0.922 g / cm ³ , MI = 2.
3, linear polyethylene (d = 4 ° C., melting point = 124 ° C., melt tension = 4 g) or polymerized using a chromium catalyst.
0.922 g / cm ³ , MI = 0.85, melting point = 126
C., melt tension = 7 g) as the main component (Table 1).

(2) Group B: (A) melt tension is 3
The linear polyethylene having a melting point of 120 ° C. or more and a melting point of 120 ° C. or more is a linear polyethylene (d = 0.922 g / cm ³ , MI = 2.
3, melting point = 124 ° C., melt tension = 4 g) or linear polyethylene polymerized using a single-site catalyst (d = 0.935 g / cm ³ , MI = 3.5, melting point = 1)
(26 ° C., melt index = 1 g), (B) as the ethylene copolymer blended in the linear polyethylene, high-pressure radically polymerized polyethylene, ethylene-vinyl acetate copolymer, ethylene-butene-1-diene copolymer An insulating resin composition containing a coalesced or ethylene-octene rubber and containing (A) and (B) as main components (Table 1).

(3) Group C: ethylene-vinyl acetate copolymer 10 having a number average molecular weight of 3 × 10 ⁴ or more or a weight average molecular weight of 3 × 10 ⁵ or more and a melting point of 60 to 80 ° C.
Volume resistivity is 5000Ω · cm at room temperature with respect to 0 parts by weight.
A semiconductive resin composition containing semiconductive carbon black as described below (Table 3).

(4) Group D: (A) a number average molecular weight of 3 × 1
0 ⁴ or more, or a weight average molecular weight of 3 × 10 ⁵ or more,
An ethylene-vinyl acetate copolymer having a melting point of 60 to 80 ° C and a high-density polyethylene as an ethylene copolymer for blending (B) (melting point = 132 ° C, d = 0.952 g / c)
m ³ , MI = 0.1), linear polyethylene (melting point = 1)
23 ° C., d = 0.925 g / cm ³ , MI = 4) or polypropylene (melting point = 167 ° C., d = 0.89 g / cm)
³ , a semiconductive resin composition (MI = 0.8) (Table 3).

(5) Group E: (A) ethylene-vinyl acetate copolymer (number average molecular weight = 50,000, weight average molecular weight = 450,000, melting point = 72 ° C.), (B) high density polyethylene (melting point = 132 ° C., d = 0.952 g / cm ³ ,
MI = 0.1) and (C) a high-density polyethylene wax (molecular weight = 4000, volatile content = 0.1%) as a hydrocarbon wax having a volatilization amount at 200 ° C. of less than 2%, a low-density polyethylene wax ( Molecular weight = 2000, Volatility =
1.7%) or a semiconductive resin composition blended with an ethylene-vinyl acetate copolymer wax (molecular weight = 6700, volatile amount = 0.3%) (Table 3).

(6) Group F: a semiconductive resin composition for a comparative example, the compositional components and composition ratios of which are shown in Table 4.

(7) Comparative Example in Table 2: An insulating resin composition for comparison, the composition of which is shown in Table 2. The characteristics of Group A, Group B and Comparative Examples (1 to 5) in Table 2 above were compared for the following items (A) and (B). In the case of things,
(A) According to JIS C 3005, the heating deformation rate at 120 ° C. exceeds 25% or (and) (B)
The sample injected into the conductor was immersed in warm water of 90 ° C., and an AC voltage of 50 Hz / 9 kV was applied between the conductor and the water for 500 days. 200 measured with an optical microscope
The number of bow title trees having a size of μm or more was 10 ³ or more, and the bow title characteristics were poor.

The evaluation test was performed as follows.

(1) Peeling test / peeling strength test: The conductor 1 of the power cable manufactured as described above is removed (FIG. 5), and the frist type inner semiconductive layer 2b is peeled from the non-crosslinked type insulator 3b ( Fig. 6) Strength (peel strength)
AEIC-CS5 (SPECIFICATIONS FOR CROSS-LINKE
D POLYEHTYLENE INSULATED SHIELDED POWER CABLES PAT
(ED 5 THROGH 46kV) at room temperature. In this method, a power cable having a peel strength of 0.5 to 4 kg / 1/2 inch and having no internal semiconductive layer component adhered to the insulator as shown in FIG. Those in which the inner semiconductive layer could not be peeled off at 0.5 to 4 kg / 1/2 inch were marked X. The results are shown in Table 5.

(2) Heat deformation test: JIS C 300
In accordance with No. 5, the heating deformation of the sample at 120 ° C. is 25
% Or less was marked with ○, and more than 25% was marked with ▲. The results are shown in Table 6.

(3) Volume resistivity test: AEIC-CS5
The volume resistivity was measured in accordance with
Those with 0 Ω · cm or less and 50000 Ω · cm or less at 90 ° C. were marked with “○”, and those not within this range were marked with “△”. The results are shown in Table 7.

(4) Extruded appearance test: A sample with good extruded appearance was marked with ○, and a foamed one with bad appearance was marked with Δ. The results are shown in Table 8.

(5) Comprehensive evaluation: In all of the above-mentioned items, those with a mark of “○” are regarded as “passed”, and at least one of them is ×, ▲, Δ, Δ
If there was a mark, it was judged as "fail". The results are shown in Table 9.

The results of the above test evaluation are shown in Tables 5 to 9. As shown in Tables 1 to 9, in the power cable of the example of the present invention, the insulator excellent in general characteristics and containing no semiconductive layer material could be easily separated and recovered.
This made it possible to recycle the insulator material.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

[Table 4]

[0052]

[Table 5]

[0053]

[Table 6]

[0054]

[Table 7]

[0055]

[Table 8]

[0056]

[Table 9]

As a recyclable power cable,
Extrusion of a frist inner semiconductive layer on a conductor, followed by applying an insulator, and extruding the same semiconductive resin composition (Frist outer semiconductive layer) as the frist inner semiconductive layer (FIG. 7) Also obtained the effects as described above.

As described above, the embodiment of the present invention has excellent heat resistance,
Also, an insulator (A) having good extrusion moldability, a small rate of heat deformation, and excellent water-resistant tree (particularly bow-resistant tree properties).
Frist semiconductive resin composition (Group C, Group D, E
By using a combination of the (group), a cable that can be recycled as a material (material recycling) is obtained, and its industrial value is extremely high.

[0059]

As described above, according to the present invention, it is possible to obtain a power cable which is excellent in various properties, and excellent in the insulating property of peeling, recovering workability and recyclability.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view of a conventional power cable.

FIG. 2 is an explanatory view showing a state where a conductor is taken out from the power cable of FIG. 1;

FIG. 3 is an explanatory view showing a state in which an inner semiconductive layer is further removed from the power cable of FIG. 1;

FIG. 4 is a schematic cross-sectional explanatory view of an embodiment of a power cable according to the present invention.

FIG. 5 is an explanatory view showing a state where a conductor is taken out from the power cable of FIG. 4 according to the present invention.

6 is an explanatory view showing a state in which an inner semiconductive layer is further removed from the power cable of FIG. 4 according to the present invention.

FIG. 7 is a schematic cross-sectional explanatory view of another embodiment of the power cable according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Conductor 2a Internal semiconductive layer (semiconductive resin composition) 2b Internal semiconductive layer (Frist type semiconductive resin composition) 3a Crosslinked polyethylene insulator 3b Insulator (non-crosslinked type heat-resistant polyethylene) 4 PVC sheath 5. External semiconductive layer (Frist type semiconductive resin composition)

Claims (6)

[Claims] 1. A power cable comprising a conductor, an inner semiconductive layer on the conductor and an insulator on the inner semiconductive layer, wherein the inner semiconductive layer has a number average molecular weight of 3 × 10 ⁴ or more or a weight average. Molecular weight of 3 × 10 ⁵ or more and melting point of 6
0-80 ° C ethylene-vinyl acetate copolymer and 100 parts by weight of the ethylene-vinyl acetate copolymer,
The semi-conductive resin composition contains a semi-conductive carbon black in a ratio such that the volume resistivity becomes 5000 Ω · cm or less at room temperature, and the insulator has a melt tension of 3 g or more and a melting point of A power cable comprising an insulating resin composition containing a non-crosslinked, heat-resistant linear polyethylene having a temperature of 120 ° C. or higher. 2. The method according to claim 1, wherein the semiconductive resin composition is used in an amount of 1 to 100 parts by weight based on 99 to 50 parts by weight of the ethylene-vinyl acetate copolymer.
2. A polyolefin having a melting point of not less than 120.degree. C. in a proportion of 50 parts by weight and containing one or more polyolefins selected from high-density polyethylene, linear polyethylene and polypropylene. Power cable. 3. The composition according to claim 1, wherein the semiconductive resin composition has a ratio of 1 to 20 parts by weight at 200 ° C. based on 100 parts by weight of the ethylene-vinyl acetate copolymer and the polyolefin having a melting point of 120 ° C. or more. 3. The power cable according to claim 2, wherein a hydrocarbon wax having a volatilization amount of less than 2% is contained. 4. A power / cable having a conductor, an inner semiconductive layer on the conductor, and an insulator on the inner semiconductive layer, wherein the inner semiconductive layer has a number average molecular weight of 3 × 10 ⁴ or more or a weight. The average molecular weight is 3 × 10 ⁵ or more, and the melting point is 60 to 80 ° C., and the volume resistivity is not more than 5000 Ω · cm at room temperature with respect to 100 parts by weight of the ethylene-vinyl acetate copolymer and the ethylene-vinyl acetate copolymer. And a semiconductive resin composition containing a semiconductive carbon black in such a ratio as follows:
A non-crosslinked, heat-resistant linear polyethylene having a melting point of 120 ° C. or higher and (2) a high-pressure radically polymerized polyethylene, ethylene vinyl acetate copolymer having a ratio such that the melt tension of the blend with the linear polyethylene is 3 g or more Polymer, ethylene ethyl acrylate copolymer, ethylene methacrylate copolymer, ethylene methyl methacrylate copolymer, ethylene propylene rubber, ethylene butene
A power cable comprising an insulating resin composition containing one or more selected from ethylene copolymers such as 1 copolymer and ethylene octene rubber. 5. The method according to claim 1, wherein the semiconductive resin composition is used in an amount of 1 to 99 parts by weight of the ethylene-vinyl acetate copolymer.
5. A polyolefin having a melting point of 50 parts by weight and a melting point of 120 DEG C. or more, wherein the polyolefin contains one or more polyolefins selected from high-density polyethylene, linear polyethylene and polypropylene. Power cable. 6. A power cable having a conductor, an inner semiconductive layer on the conductor, and an insulator on the inner semiconductive layer, wherein the inner semiconductive layer has (1) a number average molecular weight of 3 × 10
⁴ or more or an ethylene-vinyl acetate copolymer having a weight average molecular weight of 3 × 10 ⁵ or more and a melting point of 60 to 80 ° C., (2) a volume resistance to 100 parts by weight of the ethylene-vinyl acetate copolymer (3) 1 to 50 parts by weight of a melting point of 120 ° C. or more based on 99 to 50 parts by weight of the ethylene-vinyl acetate copolymer. A total amount of one or more polyolefins selected from high-density polyethylene, linear polyethylene and polypropylene and (4) the ethylene-vinyl acetate copolymer and the polyolefin having a melting point of 120 ° C. or higher. 1 to 20 parts by weight to 2 parts by weight
It is constituted by a semiconductive resin composition containing a hydrocarbon wax having a volatilization amount of less than 2% at 00 ° C.,
The insulator is a non-crosslinked, heat-resistant linear polyethylene having a melting point of 120 ° C. or more, and (2) a high-pressure high-pressure mixture having a melt tension of 3 g or more of a blend with the linear polyethylene. Radical polymerized polyethylene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene methacrylate copolymer, ethylene methyl methacrylate copolymer, ethylene propylene rubber, ethylene butene-1 copolymer, ethylene octene rubber and other ethylene copolymers A power cable comprising an insulating resin composition containing one or more selected from polymers.