JPS62272405A - Fireproof cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (1-10) The present invention relates to a heat-resistant cable coated with a heat-treated mixture of two or more ethylene copolymers. It is an object of the present invention to provide a heat-resistant cable that not only has excellent adhesion and adhesion to bare wires and sheaths, but also has excellent electrical insulation and heat resistance, and can be manufactured by a simple method. This is the purpose.

Differential speed J and leather electric wires are not only used for simply transporting electricity, but as industry becomes more sophisticated, their applications are expanding to a wide range of fields. For example, in the field of communication cables.

With the multiplexing of digital signals, local cables, intercity cables, carrier cables, coaxial cables are used for long distances between cities, and submarine cables are used for communication with overseas countries. is used.

In addition, it is used in a wide variety of industrial fields, including coaxial cables for feeding antenna power at television transmitting stations and cables for television video cameras. As described above, with the diversification and high-performance use of cables, it is no longer possible to adequately cover various types of cables with conventional sheathing materials or coating methods.

For example, an ultra-high voltage cable expands due to heat generated when a large amount of current passes through it, and cools and contracts when the current decreases.

These repeated rises and falls in temperature create gaps and distortions in the insulation and sheath, causing damage to the cable. As a countermeasure to these problems, an oil field cable (OF) is used, in which insulating oil is passed between spirals inside the cable and a certain amount of oil pressure is applied thereto to adjust expansion and contraction due to temperature. , metal sheaths such as lead and aluminum are used to withstand hydraulic pressure. However, with these methods, the weight of the entire cable increases, workability such as construction is poor, and corrosion occurs in the sheath material as the insulating oil deteriorates. Also, inert gas (
For example, gas pressure (nitrogen) is sealed inside the cable (CF cable), but it is clear that monitoring and adjusting the gas pressure is difficult.

In addition, electric cables include those insulated with cross-linked polyethylene (CV, GE), and those insulated with polyethylene and sheathed with polyvinyl chloride (EV).
Synthetic rubber (for example, ethylene-propylene rubber (EP)
R), styrene-butadiene rubber (5BR), etc. are now being used. Like cross-linked polyethylene, these rubber sheathing materials have excellent flexibility and water resistance, but because they have poor adhesion to conductors and sheathing materials, they are subject to repeated bending and weather resistance (repeated temperature changes). On the other hand, gaps occur between each layer, causing a decrease in weather resistance, water resistance, etc. Furthermore, compared to polyethylene materials, rubber materials are inferior in electrical properties such as insulation resistance, dielectric strength, and high frequency characteristics. In addition, even with cross-linked polyethylene, which has good electrical properties, it has poor adhesion with conductors and sheathing materials, which not only causes the above-mentioned defects, but also causes damage to the entire sheathing material during electron beam crosslinking, silane crosslinking, and peroxide crosslinking processes. Since it is difficult to achieve uniform crosslinking (electron beam or silane crosslinking has a high crosslinking density), crosslinked forms remain, which can cause cracks during long-term use. Furthermore, the manufacturing process of these crosslinked products requires large-scale equipment and has a problem of poor production efficiency.

From the above, the present invention does not have these drawbacks (problems) and not only has excellent heat resistance.

It has good insulation ability, has good adhesion to the conductor and sheath, and can be manufactured more easily and at a lower cost than conventional methods, and has good heat resistance and flexibility. is to get the cable.

According to the present invention, these problems are solved when the cross-sectional area is 10
Copper or aluminum filaments with a thickness of 1 to 35 cm exceeding 0 mm' but not more than 4000 mm' (A)
At least (1) ethylene and (2) copolymerization ratio is 0
．． A monomer having at most 30 carbon atoms and having at least one double bond and having an epoxy group or a hydroxyl group of 1 to 20.0 mol% [hereinafter referred to as [comonomer (1) J]] Ethylene copolymer (A)
and (B) at least (1) ethylene and (2) the epoxy group or hydroxyl group in the ethylene copolymer (A) having a copolymerization ratio of 0.1 to 20.0 mol%. Ethylene-based copolymers CB) with monomers having functional groups that can result in an extraction residue of at least 60% after extraction treatment with boiling toluene for 3 hours by heating at a temperature of 300° C. for 20 minutes 39 to 1% by weight A heat-resistant cable coated with a heating product comprising at least 80% of said extraction residue by heating a mixture of.

It can be solved by The present invention will be explained in detail below.

(A) Ethylene copolymer (A) The ethylene copolymer (A) used in the present invention is ethylene and the comonomer (1), or an unsaturated carboxylic acid ester and/or comonomer (1) containing at most 30 carbon atoms.
or vinyl ester” [hereinafter referred to as “comonomer (2)”]
It is a copolymer with Comonomer (1) of this copolymer
has an epoxy group or a hydroxyl group, and has at least one double bond and has a carbon number of at most 8 to 30
There are seven tsumasa. Among these monomers, monomers having an epoxy group (hereinafter referred to as "epoxy compounds")
As a representative example, the general formula is the following formula [Formula (I) or I
II) Formula].

R5RO CH2= C-RG -0-R7-C-CH2(m)
Typical examples of heptamines represented by formulas (1) to l) include butenecarboxylic acid monoglycidyl ester, glycidyl methacrylate, glycidyl acrylate, methylglycidyl acrylate, methylglycidyl methacrylate, itaconic acid glycidyl ester, 7. 8-
Examples include epoxy-1-octyl methacrylate, methyl itaconate glycidyl ester, 7,8-epoxy-1-octyl vinyl ether, vinyl glycidyl ether, allyl glycidyl ether, and methallyl glycidyl ether.

Among the comonomers (1), representative examples of monomers having a hydroxyl group (hereinafter referred to as "hydroxyl compounds") include α-flukenyl alcohol and hydroxyalkyl (meth)acrylate having 3 to 25 carbon atoms. can be given. Typical examples of hydroxyl-based compounds include hydroxymethyl (meth)acrylate, droxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate.
Mention may be made of acrylate, hydroxyhexyl (meth)acrylate and allylfurcol. Further examples include saponified products obtained by saponifying copolymers of ethylene and vinyl esters (especially vinyl acetate).

The comonomer (2) may also include methyl (meth)acrylate, ethyl (meth)acrylate, alkoxyalkyl (meth)acrylate, and diethyl fumarate having at most 30 carbon atoms (preferably 10 or less). Mention may be made of unsaturated carboxylic acid esters and vinyl esters having at most 30 carbon atoms, such as vinyl acetate and vinyl propionate.

(B) Ethylene copolymer (B) Also, the ethylene copolymer used in the present invention (
B) is ethylene and the above-mentioned ethylene copolymer (A)
A monomer having a functional group that can form an ester bond with an epoxy group or a hydroxyl group in C by heating at a temperature of 300°C for 20 minutes.
)" or a copolymer of these and the above-mentioned comonomer (2).

Representative examples of this comonomer (3) include acrylic acid,
unsaturated monocarboxylic acids having at most 25 carbon atoms, such as methacrylic acid and crotonic acid, and maleic acid;
fumaric acid, tetrahydrophthalic acid, 4-methylcyclohexane-4-ene-1,2-carboxylic acid, itaconic acid,
Citraconic acid and bicyclo(2,2,1)-hebuta-
5-ene-2,3-dicarboxylic acid with 4 or more carbon atoms
Mention may be made of the 50 unsaturated dicarboxylic acids as well as the anhydrides of these unsaturated dicarboxylic acids.

Among the above ethylene copolymers (B), copolymers of ethylene and unsaturated dicarboxylic anhydrides or multicomponent copolymers of these and unsaturated dicarboxylic esters and/or vinyl esters are hydrolyzed and The dicarboxylic acid anhydride units of these copolymers can be converted to dicarboxylic acid units or Hafester units by modification with alcohol. Ethylene copolymers (B) obtained by replacing part or all of the acid anhydride units with dicarboxylic acid units or halfester units can also be preferably used.

To carry out the hydrolysis, the ethylene copolymer (B
) in the presence of a catalyst (e.g. tertiary amine) in an organic solvent (e.g. toluene) that dissolves the copolymer.
It can be obtained by reacting with water for 0.5 to 10 hours (preferably 2 to 6 hours, preferably 3 to 6 hours) at a temperature of ~100°C, followed by neutralization with acid.

To perform alcohol modification, the ethylene copolymer (B) can be obtained by the solution method or kneading method described later.

The solution method is similar to the case of hydrolysis, in which the reaction is carried out in an organic solvent in the presence or absence of the above-mentioned catalyst (the reaction is slow in its absence).
2 minutes to 5 hours at the reflux temperature of the alcohol used in
Preferably from 2 minutes to 2 hours, preferably from 15 minutes to 1 hour.
time).

On the other hand, in the kneading method, tertiary amine is usually added in an amount of 0.01 to 1.0 parts by weight (preferably 0.05 to 0.5 parts by weight) per 100 parts by weight of the ethylene copolymer (A). and generally from 0.1 to dicarboxylic acid units in the copolymer.
3.0 times mole (preferably 1.0 to 2.0 times mole)
The saturated alcohol is mixed at a temperature above the melting point of the ethylene copolymer (B) but below the boiling point of the alcohol used, using a kneading machine such as the Banbury Mixer 1 extruder, which is commonly used in the fields of rubber and synthetic resins. This is a method in which the reaction is carried out while kneading for several minutes to several tens of minutes (preferably 10 to 30 minutes).

The saturated alcohol used in the above modification with alcohol is a linear or branched saturated alcohol having 1 to 12 carbon atoms, and includes methyl alcohol, ethyl alcohol, and -butyl alcohol.

In the case of the above hydrolysis and in the case of modification with alcohol, the conversion rate to dicarboxylic acid and the halfesterization rate are both 0.5 to 100%, and 1060 to 100%.
100% is desirable.

The copolymerization ratio of ethylene in these ethylene copolymers is 50 to 99.88 mol%, preferably 60 to 99.8 mol%, and particularly preferably 85 to 89.0 mol%. In addition, the copolymerization ratio of comonomer (1) or comonomer (3) is 0.01 to 20 mol% as the total amount thereof.
and preferably 0.1 to 20 mol%, Q, 1 to 1
5 mol% is preferred. The copolymerization ratio of comonomer (1) in these copolymers is Q, 01 as their total amount.
If the amount is less than mol%, the adhesion to the filamentous material described below is poor.

On the other hand, even if the copolymer content exceeds 20 mol%, although the characteristics of the present invention are exhibited, it is not preferable from the manufacturing and economical viewpoints.Furthermore, the copolymerization ratio of the comonomer (2) is at most 30 mol%. The content is preferably from 0.1 to 30 mol%, particularly preferably from 0.5 to 25 mol%. Comonomer (2)
If a copolymer with a total copolymerization ratio of more than 30 mol % is used, the softening point of the copolymer will be high and fluidity will be impaired, which is not only undesirable.
It is also unfavorable from an economic point of view.

The ethylene copolymer of the present invention usually has a temperature of 500 to 300σK.
g/cm' in the presence of a chain transfer catalyst (e.g., oxygen, organic peroxide, azo compound, diazo compound) in the temperature range of 40 to 300°C. ) can be obtained by copolymerizing these with comonomer (2). Saturated or unsaturated hydrocarbons (eg.

(ethane, propane, propylene) are used.

Of this chain transfer agent, a very small amount of unsaturated hydrocarbon is copolymerized.

Melt flow index of the ethylene copolymer of the present invention (measured under condition 4 according to JIS K7210,
(hereinafter referred to as rNFRJ) is generally 0.001 to 10
00 g/10 minutes, 0.05-500 g7
10 minutes is preferable, and 0.1 to 500 g/710 minutes is particularly preferable. If these ethylene copolymers have an MFR of less than 0.01 g/10 minutes, moldability is poor.

The method for producing these ethylene copolymers by copolymerization is well known.

Furthermore, among the ethylene-based copolymers (A), the method of producing them by hydrolysis and/or modification with alcohol is also a well-known method.

(C) Production of mixture (1) Mixing ratio In producing the mixture of the present invention, ethylene copolymer (A) and ethylene copolymer (B
) Ethylene copolymer (A) in the total amount (total)
The mixing ratio of the ethylene copolymer (B) is 1 to 99% by weight [that is, the mixing ratio of the ethylene copolymer (B) is 98 to 1% by weight], and the mixing ratio is 5 to 8% by weight.
5% by weight is desirable, particularly 10-90% by weight. Ethylene copolymer (A) in the total amount of ethylene copolymer (A) and ethylene copolymer (B)
Even if the mixing ratio is less than 1% by weight or more than 89% by weight, the crosslinking of the mixture by the method described later will be insufficient, and for example, the adhesion with the filamentous material described later will be poor.

(2) Mixing method To produce this mixture, it is sufficient to uniformly mix the ethylene copolymer (A) and the ethylene copolymer (B). Triblending may be carried out using a commonly used mixer such as a Henschel mixer, or melt kneading may be carried out using a mixer such as a Banbury, extruder, or roll mill. At this time, a more uniform mixture can be obtained by triblending in advance and melt-kneading the resulting mixture. When melt-kneading, it is necessary that the ethylene copolymer (A) and the ethylene copolymer (B) do not substantially undergo a crosslinking reaction (
If the resulting mixture is crosslinked, it will not only deteriorate the moldability when molding the resulting mixture as described below, but also cause a decrease in the shape of the intended molded product and the heat resistance when crosslinking the molded product. Therefore, the melt-kneading temperature is preferably room temperature (20°C) to 150°C, and preferably 140°C or lower, although it depends on the type and viscosity of the ethylene polymer used.

As a guideline for ``substantially no crosslinking,'' ``residual aroma with a diameter of 0.1 micron or more after extraction treatment in boiling toluene for 3 hours'' (hereinafter referred to as ``extraction residue'') is generally 15% by weight. % or less, preferably 10% by weight or less, optimally 5% by weight or less.

In producing this mixture, stabilizers against oxygen, light (ultraviolet light) and heat, metal deterioration inhibitors, *flame agents, electrical property improvers, and antistatic agents commonly used in the field of olefinic polymers are used. , additives such as lubricants, processability improvers, and tackiness improvers may be added to the extent that they do not impair the properties (physical properties) of the crosslinked product of the present invention.Furthermore, primary to tertiary monoamines may be added. , P-toluenesulfonic acid, diamine, and a quaternary ammonium salt, the ethylene copolymer (A) and the ethylene copolymer (B
), the amount added is usually at most 5.0 parts by weight (preferably 0.01 to 3.0 parts by weight) per 100 parts by weight of the total amount of these ethylene copolymers.
It is also possible to improve the insulation properties by adding ceramics having insulation properties such as alumina and silicon nitride. Furthermore, the functionality of the present invention can be further improved by filling it with inorganic powder, glass fiber, glass pieces, etc.

(D) Copper and aluminum filament Further, the copper and aluminum filament used in the present invention conforms to the electrical conductivity of JIS C-3002-1975 (Electrical copper wire and aluminum wire test method), Item 6. The electrical conductivity measured according to the method is 60% or more, and it is manufactured from copper and aluminum metals and alloys containing these metals as main components (50% by weight or more). In addition, the cross-sectional area of the filament exceeds 100 mm, but is less than 4000 mm, and loOmm
2 but preferably 9900 mm or less, and particularly preferably 100 mm or less but 3400 mm or less.The thickness of this cross-sectional area is determined by the amount of current used. The wire size is determined by the cross-sectional area.For example, 330
In the case of a 0-port single-core cross-linked polyethylene cable, when the nominal cross-sectional area of the conductor is 800 mtn', the number of strands/wire diameter = 9872.9 mm has a circular compressed shape, and the thickness of the polyethylene insulating layer is 4.0 mm, and the sheath thickness is 2.9 m (JIS C-9908,
Figures 1, 2, and 3 show enlarged cross-sectional views of typical large electric wires, flat electric wires, and cobblestone electric wires used in the present invention. It is a conductor (a filament), 2 is a covering (a cross-linked mixture), 3 is a sheath, and 4 is an inclusion. The thickness of the conductor (striated object) coating is JISC-990.
8 to C-9905 (B00
For Porto and below, JIS C-9905, 600 volts or 60,000 volts, C-9908, for 60,000 volts and above, undecided).

For example, in a 3,300 port single-core cross-linked polyethylene cable, the conductor's nominal cross-sectional area is 1,000 mm, the number of strands is 127, the strand diameter is 3.2 mm, and the thickness of the insulation layer is 4.
It is 5■. In a 3300 port three-core single-sheath type cable, if the nominal cross-sectional area of the conductor is 200 m rn', the number of strands is 37, the strand diameter is 2.8 mm, and the thickness of the insulation layer is 3.
．． It is 5a+m. In addition, in the case of the 8800 volt three-core single-sheath type, when the conductor cross-sectional area is 250 mrn'', the number of strands is 61, the strand diameter is 2.3 mm+, and the thickness of the insulating layer is 4.
The thickness of the sheath is 4.0 mm, and the outer diameter of the insulating layer is 29.7 mm. It has been revealed that these high voltage cross-linked polyethylene cables are used in 3300 port and 6800 port power circuits.

These power cables are categorized by their main uses: general use, mobile use, overhead use, buried use, underwater use, and ultra-high pressure use.

For example, the working voltage is 800 to 275,000 volts, the number of wire cores is divided into single core, three core, and center of gravity, and even the structure of the main sheath of the cable is specified.

(E) Manufacture of Cable To manufacture the cable of the present invention, methods generally practiced in the electric wire industry may be applied. A typical method is to pass an electric wire through the center using an extruder with a crosshead, and uniformly coat the surface layer with the molten mixture when there is only one filament. Also, even in the case of two filaments or in the case of a cable, the thickness of the mixture of the present invention, which is a coating, can be manufactured in the same manner as described above. Oa+m or more, preferably low to 35mII, especially 1.5mm to 35m
layers are preferred. If the thickness exceeds 35+s, insulation properties can be ensured depending on the intended use of the wire, but the wire lacks flexibility and poses problems during wiring work and use.

Also, 1. If it is less than Om layer, it is not preferable because the insulation property is insufficient.As mentioned above, the thickness of the insulation coating (crosslinked material of the mixture) varies depending on the use of the wire, but eo
ov or more, approximately 4.0 to 10 mm is suitable. Furthermore, in the case of three-core, cobblestone wires, the wires coated with the insulating coating layer are bundled with a sheath material. This sheathing is carried out in the same manner as described above.

In producing the electric wire of the present invention, the mixture containing the ethylene copolymer (A) and the ethylene polymer (B) is not crosslinked in terms of wood quality, but is molded near the glue loss head of the extruder. After that, the temperature at which the mixture crosslinks (120~
Heat treatment is performed by reheating at 990° C. to completely crosslink.

In cases where the crosslinking accelerator is contained and in cases where it is not contained,
Although the temperature varies, the heat treatment is usually carried out in a temperature range of 120 to 990°C; if it is less than 120°C, crosslinking will not proceed and the heat resistance of the coating will be insufficient.

On the other hand, if the temperature exceeds 990°C, at least a portion of the ethylene copolymer constituting the mixture begins to deteriorate, the surface changes color, and the strength decreases, which is undesirable. Although it varies depending on the temperature and the presence or absence of a crosslinking accelerator, it is usually 1 to 10 minutes at 250°C or higher. On the other hand, at temperatures below 250°C, it takes 2 minutes to
30 minutes are required.

In addition, it is preferable to carry out under an atmosphere of inert gas (for example, nitrogen gas) in order to suppress surface oxidation, and furthermore, during heat treatment, the mixture may be melted due to shrinkage or deformation at both ends. It is necessary to apply tension to the part. The tension must be below the level at which the center line does not cut, but it must be higher than the level at which the line does not sag due to its own blade.

In addition to these methods, it is also possible to coat the mixture using an extruder and simultaneously raise the temperature of the head to 180-990°C to crosslink the mixture, but this may cause the nozzle at the tip to become clogged due to gel formation. In order to manufacture a coated cable by an extrusion method such as the one described above, which is undesirable due to the surface becoming uneven with gel-like substances, the process is generally carried out at a temperature range in which the mixture is melted but not crosslinked.

Therefore, the temperature is preferably 80 to 180°C, especially 100 to 150°C (preferably 100 to 140°C).
) is desired, followed by cooling and heating as described above until the mixture is almost completely crosslinked.

As a guideline for crosslinking, the extraction residue is preferably 80% or more, preferably 70% or more, and most preferably 75% or more.

- The present invention will be explained in more detail below with reference to Examples.

In the Examples and Comparative Examples, the heat resistance was measured using a solder bath adjusted to 300°C [Lead/Tin = 90/1].
0 (weight ratio)] for 60 seconds for evaluation.

The mixture of ethylene copolymer (A) and ethylene copolymer (B) used in Examples and Comparative Examples is shown below.

Ethylene copolymer (A) and ethylene copolymer (B)
,! -(7) Mixture L, 1. is 300g/
Ethylene-acrylic acid copolymer (density 0
．． 954g/cm', acrylic acid copolymerization ratio 2
0% by weight, hereinafter referred to as rEAA J ) and an ethylene-vinyl acetate copolymer having a vinyl acetate copolymerization ratio of 28% by weight. 75g/10
(mixture ratio 50:
50 (weight ratio), hereinafter referred to as "mixture (1)"],
Ethylene-methacrylic acid copolymer with A, ■, 200 g/10 min (density 0.950 g/cm
', methacrylic acid copolymerization ratio 25% by weight) and the above saponification degree [mixing ratio 5Q:50 (weight ratio), hereinafter referred to as "Mixture (II) J]", M, 1. is 212g/
Ethylene-ethyl acrylate-maleic anhydride ternary copolymer (ethyl acrylate copolymerization ratio: 30.7% by weight, maleic anhydride copolymerization ratio: 1.7%)
% by weight (hereinafter referred to as rEEMJ) and M, 1. is 123
g 710 minutes (copolymerization ratio of methyl methacrylate: 20.7i% by weight, copolymerization ratio of hydroxymethacrylate: 11.7% by weight, hereinafter referred to as "rEEH") Mixture with [Mixing ratio 50:
50 (weight ratio), hereinafter referred to as "mixture (■)"] and M, 1. A terpolymer of ethylene-methyl methacrylate-maleic anhydride (copolymerization ratio of methyl methacrylate: 20.51% by weight, copolymerization ratio of maleic anhydride: 3.1% by weight) with a weight ratio of 105 g/10 minutes and ethylene. - Methyl methacrylate-glycidyl methacrylate terpolymer (copolymerization ratio of methyl methacrylate: 18.6% by weight, copolymerization ratio of glycidyl methacrylate: 12.7ffii%, hereinafter referred to as rEBMJ)
[Mixing ratio 30:70 (weight ratio),
Hereinafter referred to as "mixture (■)"] was used. Note that these mixtures were produced by tri-blending the respective copolymers or terpolymers for 5 minutes using a Henschel mixer.

Examples 1-11, Comparative Examples 1-6 Mixtures (I) to IV) obtained as above
as well as EAA and EEM used to produce the mixture.
, EEH, EBM, and saponified material each using an extruder with a crosshead die (diameter: 40 mm, set temperature: c
too℃, C110℃, C3120℃, D
(120°C), cables were manufactured so that the filament shown in Table 1 was centered (the thickness of the covering material is shown in Table 1).

The cable thus obtained was heat-treated in a heating furnace (length: 50 ca) set at a temperature of 300° C. in a nitrogen gas atmosphere at a rate of 50 co+/min.

When we tested the heat resistance of the resulting cable, we found that
No deformation was observed in the sheathing materials of the cables obtained in any of the Examples, but all the cables obtained in the Comparative Examples melted during heat treatment.

In addition, the resulting cable was wound around a round bar with a diameter of 30 cm, and the surface condition was observed for flexibility and adhesion to copper and aluminum.

The cables obtained in all the examples had smooth surfaces, and no cracks showing visible filaments were observed. On the other hand, the cables obtained in all comparative examples had a good surface condition, but peeling occurred on the surface of the filament, and when the cable was removed from the round bar, peeling occurred partially. Admitted.

(The following are blank spaces) Table 1 (Part 1) Table 1 (Part 2) From the results of the above examples and comparative examples, the cable of the present invention not only has high flexibility and excellent heat resistance, but also has excellent heat resistance. It is clear that it can be fully utilized for applications such as high-voltage crosslinked polyethylene cable (C■ cable) specified in the JIS standard.

The heat-resistant cable of the present invention exhibits the following effects (features) including its manufacturing process.

(1) Since molding and crosslinking can be performed in a continuous process, adhesion to copper and aluminum filaments can be simultaneously performed in the crosslinking process, so that steps can be omitted.

(2) Since a sufficiently good crosslinked product can be obtained without using a crosslinking agent, electrical properties (eg, insulation, withstand voltage, dielectric loss tangent, etc.) are excellent.

(3) It has good flexibility because it does not require the use of a crosslinking agent.

(4) Due to its excellent heat resistance, it also has excellent insulation properties at high temperatures as a high voltage cable.

The heat-resistant cable of the present invention can be used in a wide variety of ways to achieve the above-mentioned effects. Typical applications are shown below.

(1) General, mobile, aerial cable (2) Underwater cable,
Cable for direct burial in special environments (3) Cable for ultra-high voltage

[Brief explanation of the drawing]

1 to 3 are enlarged cross-sectional views of typical heat-resistant cables of the present invention. FIG. 1 is an enlarged sectional view of the -6 cable, FIG. 2 is a three-core cable, and FIG. 3 is a center-of-gravity cable.

Claims (1)

[Claims] The cross-sectional area exceeds 100mm^2, but it is 4000mm^
2 or less copper or aluminum filaments with a thickness of 1 to 3
(A) at least (1) ethylene and (2)
Ethylene copolymer with a monomer having an epoxy group or a hydroxyl group and having at least one double bond and having at most 30 carbon atoms in a copolymerization ratio of 0.1 to 20.0 mol% (A) 1 to 99% by weight and (B) the ethylene copolymer having a copolymerization ratio of at least (1) ethylene and (2) 0.1 to 20.0% by mole (
A) Ethylene-based monomers with epoxy or hydroxyl groups and functional groups that can result in an extraction residue of at least 60% after extraction treatment with boiling toluene for 3 hours by heating at a temperature of 300°C for 20 minutes A heat-resistant cable which is coated with a heating product of at least 60% extraction residue obtained by heating a mixture of 99 to 1% by weight of copolymer (B).