KR101804906B1 - Power cable - Google Patents

Abstract

The present invention relates to a power cable. According to the present invention, provided is the power cable which comprises: at least one conductor; an insulator formed with polyolefin while surrounding the conductor; an inclusion formed to surround the insulator; a binder tape formed to surround the inclusions; and a sheath formed with the polyolefin while surrounding the binder tape. The inclusions and the binder tape are formed with a nylon yarn, which is a film formed by extruding a mixture of a mass of stone flour and polyamide at high temperatures.

Description

Power cable {Power cable}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cable, and more particularly, to a power cable having excellent heat resistance and improved flame retardancy and low toxicity, in place of a composition for forming an insulator, an inclusion, a binder tape and a sheath.

Generally, cables have been developed so that various coating layers such as insulating layers, inclusions, and sheath layers are formed and have heat resistance.

In the conventional cable, the insulating layer covering the conductor was made of polypropylene (P.P.), allowing the temperature of the conductor to withstand 90.degree. C. using crosslinked polyethylene.

However, when the polypropylene (PP) of the conventional cable is weak in heat resistance and the cable is vulcanized at a high temperature, it may be deformed or melted inside, and when the sheath layer is peeled, an insulation layer of polypropylene (PP) There is a problem that harmful substances are generated due to combustion of phosphorus inclusions.

In addition, in order to realize flame retardancy in a cable, a conventional cable has a flame retardancy by using a polymer resin or a flame retardant containing a halogen element in a sheath layer.

However, a cable constituted by a sheath layer containing a halogen element has a problem of generating harmful gas such as hydrogen chloride gas and dioxin when burned due to incineration or fire.

These harmful gases are not only fatal to the body but also cause problems of corrosion of various devices.

Therefore, there is a need to develop a technique for improving the heat resistance of the cable, and enhancing the flame retardancy and low toxicity.

In order to solve the above problems, the present invention can provide a power cable having excellent heat resistance, improved flame retardancy and low toxicity, in place of a composition for forming an insulator, an inclusion, a binder tape and a sheath.

In order to solve the above problems, a power cable according to a first embodiment of the present invention is a power cable comprising: at least one conductor; An insulator formed of polyolefin to surround the conductor; An inclusion formed so as to surround the insulator; A binder tape formed to surround the inclusions, and a sheath formed of polyolefin which surrounds the binder tape, wherein the inclusions and the binder tape are formed of a nylon yarn, which is a film formed by extruding a mixture of a lump of stones and polyamide, It is possible to provide a cable for electric power.

In addition, the nylon yarn is characterized in that 10 to 90% by weight of the abrasive mass and 10 to 90% by weight of the polyamide are mixed.

In addition, the lozenge is characterized by having a size of 2 to 5 mm mixed with a resin in a stone powder having a particle size of 2000 to 5000 mesh.

Further, the insulator is characterized by being formed of the polyolefin comprising a polyethylene copolymer, magnesium hydroxide, trimethoxyvinylsilane and an antioxidant.

The polyolefin of the insulator is characterized by containing 35 to 45% by weight of the polyethylene copolymer, 50 to 60% by weight of magnesium hydroxide, 1 to 3% by weight of trimethoxyvinylsilane, and 2 to 4% by weight of an antioxidant do.

Further, the trimethoxyvinylsilane is characterized by being used by hydrolyzing a methoxy group.

In addition, the antioxidant is a mixture of propyl gallate, butalitate, hardoxytoluene, sodium gluconate, and lime stone.

Further, the sheath is characterized by being formed of the above-mentioned polyolefin including ethylene ethyl acrylate copolymer, ethylene vinyl acetate copolymer, polyethylene, magnesium hydroxide and carbon black.

Also, the polyolefin of the sheath may contain 20 to 30% by weight of the ethylene ethyl acrylate copolymer, 5 to 15% by weight of ethylene vinyl acetate copolymer, 10 to 20% by weight of polyethylene, 40 to 50% by weight of magnesium hydroxide, 3% by weight.

The ethylene vinyl acetate copolymer is characterized by having a linear polymerization structure.

The power cable may further include a coating layer coated on the surface of the sheath, wherein the coating layer includes a mixture of a silane compound and a silica sol and a reinforcing agent.

The power cable according to the embodiment of the present invention constitutes an insulator and a sheath formed of polyolefin, and the insulator and the inclusions are replaced with a material having enhanced flame retardancy and low toxicity, so that heat resistance is excellent, and flame retardancy and low toxicity are improved.

Also, harmful substances generated when the sheath is peeled and burned by an external impact can be minimized.

1 is a sectional view showing a power cable according to a first embodiment of the present invention;
FIG. 2 is a sectional view showing a state in which a coating layer of a power cable according to the first embodiment of the present invention is further included. FIG.

Hereinafter, the description of the present invention with reference to the drawings is not limited to a specific embodiment, and various transformations can be applied and various embodiments can be made. It is to be understood that the following description covers all changes, equivalents, and alternatives falling within the spirit and scope of the present invention.

In the following description, the terms first, second, and the like are used to describe various components and are not limited to their own meaning, and are used only for the purpose of distinguishing one component from another component.

Like reference numerals used throughout the specification denote like elements.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It is also to be understood that the terms " comprising, "" comprising, "or" having ", and the like are intended to designate the presence of stated features, integers, And should not be construed to preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2.

1 is a cross-sectional view illustrating a power cable according to a first embodiment of the present invention.

2 is a cross-sectional view illustrating a state in which a coating layer of a power cable according to a first embodiment of the present invention is further included.

Referring to FIG. 1, a power cable according to a first embodiment of the present invention may include a conductor 10, an insulator 20, an inclusion 30, a binder tape 40, and a sheath 50.

That is, the power cable 1 may be formed by wrapping the conductor 10 in the order of the insulator 20, the inclusions, the binder tape 40, and the sheath 50.

Specifically, the conductors 10 may be formed of one or more of copper (Cu) and aluminum (Al).

For example, the plurality of conductors 10 may be bundles, and the number of bundles of conductors 10 may be one or more. 1, a plurality of conductors 10 are shown as three bundles, but the present invention is not limited thereto.

The insulator 20 is formed so as to surround at least one conductor 10 so that the current flowing to the conductor 10 is not transmitted to the outside.

Further, the insulator 20 may be formed of polyolefin. Conventionally, crosslinked polyethylene (XLPE) is used as the insulator 20, but crosslinked polyethylene (XLPE) has a low melting point and softening point, making it difficult to use it in a high-voltage power cable.

In addition, crosslinked polyethylene (XLPE) generates harmful substances during combustion, and these harmful substances are not only fatal to the human body but also have a disadvantage of corroding equipment and parts.

That is, the present invention is to replace such crosslinked polyethylene (XLPE) with a polyolefin to improve low toxicity and flame retardancy.

Here, the polyolefin forming the insulator may include a polyethylene copolymer, magnesium hydroxide, trimethoxyvinylsilane and an antioxidant.

The polyethylene copolymer is a base resin of an insulator (20) polyolefin, and may be a copolymer having a tertiary double bond at the end of a side chain in polyethylene. In addition, the side chain may be long.

35 to 45% by weight of such a polyethylene copolymer may be contained, and most preferably 40% by weight.

If the content of the polyethylene copolymer is less than 35% by weight, the effect of reducing the generation of harmful substances is insignificant, and the mechanical properties and heat resistance of the polyethylene copolymer deteriorate. When the polyethylene copolymer content exceeds 45% by weight, the shrinkage ratio of the insulator increases, Can be lowered.

Magnesium hydroxide is an inorganic flame retardant and is incorporated in the insulator 20 to improve flame retardancy and heat-sealability.

Such magnesium hydroxide may include 50 to 60 wt%, most preferably 55 wt%.

If the amount of the magnesium hydroxide is less than 50% by weight, the flame retardancy and the heat-sealability may be deteriorated and the smoke generation rate may be increased. If the magnesium hydroxide content is more than 60% by weight, abrasion resistance and mechanical properties may be deteriorated.

Trimethoxyvinylsilane is a silane coupling agent, which can further improve abrasion resistance.

As such, trimethoxyvinylsilane is most preferable as the silane coupling agent, but triethoxyvinylsilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl ) -3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and the like can also be used.

Such trimethoxyvinylsilane may be contained in an amount of 1 to 3% by weight, and most preferably 2% by weight.

If the content of trimethoxyvinylsilane is less than 1% by weight, the effect of improving wear resistance may be insignificant. If the content of trimethoxyvinylsilane exceeds 3% by weight, the stability of the insulator 20 sharply decreases and the adhesion to the conductor 10 is decreased .

Further, trimethoxyvinylsilane can be used by hydrolysis. That is, the methoxy group of the trimethoxyvinylsilane can be hydrolyzed to be well mixed with other compositions of the polyolefin of the insulator 20. [

The antioxidant is included in the insulator 20 to inhibit the generation of radicals, inhibit the peroxide decomposition reaction to prevent oxidation, and improve the heat resistance.

The antioxidant is most preferably a mixture of propyl gallate, butylated hydroxytoluene, sodium gluconate, and limestone, but is not limited thereto. Examples of the antioxidant include phenol antioxidants, amine antioxidants, sulfur antioxidants, And a phosphorous ester-based antioxidant may be used.

Such an antioxidant may comprise 2 to 4% by weight, most preferably 3% by weight.

If the content of the antioxidant is less than 2% by weight, the antioxidant effect may be insufficient. If the content of the antioxidant is more than 4% by weight, the antioxidant effect may not be improved as compared with the content, Is inefficient.

Further, the polyolefin of the insulator 20 may further include an additive.

The additive may be at least one of wax, deterioration inhibitor, colorant, crosslinking aid, tackifier, lubricant, softener, filler and processing aid, and various additives may be used.

The additive may comprise from 2 to 4% by weight, most preferably 3% by weight.

The wax improves the compatibility between the compositions of the insulator 20, so that the mixing can be performed well. Such a wax may include one of carnauba wax and crystalline wax.

The inclusions 30 may be formed to surround the insulator 20. That is, it can be filled between the insulator 20 and the binder tape 40.

The inclusions 30 are formed so as to have high heat resistance and flame retardancy so that the heat of the conductor 10 due to the current is retained,

Conventionally, ordinary rubber or polypropylene yarns are used as the inclusions 30, but they are expensive and generate toxic substances during combustion.

That is, the present invention is to replace such a general rubber or polypropylene with nylon yarn to improve low toxicity, heat resistance and flame retardancy.

The inclusions 30 may be formed of a nylon yarn, which is a film formed by extruding a mixture of abrasive grains and polyamide.

More specifically, the nylon is produced by mixing a resin in a stone to prepare a mass of stone, mixing the mass of the mass of the mass of the stone and the polyamide in a mixing device, mixing the mass of the mass of stone and the polyamide, And extruding a film having a predetermined thickness and thickness, and feeding the extruded film to a stretching machine to lower the linear density, thereby producing a nylon yarn.

The step of mixing the resin with the resin in the step of preparing the clay can produce a clay body having a size of 2 to 5 mm by mixing the resin with the clay having a particle size of 2000 to 5000 mesh.

At this time, when the particle size of the abrasive is 1000mesh or less, or when the particle size is 5000mesh or more, it is most preferable that the particle size is too small or too large to produce the abrasive agglomerates.

In the step of mixing and mixing the produced abrasive grains and the polyamide into the mixing device, 10 to 90% by weight of the abrasive mass and 10 to 90% by weight of the polyamide may be mixed in the mixing device.

As described above, when mixing the clay loam and the polyamide, the mixing ratio of the clay loam is high, the flame retardancy due to the clay increases, and the mixing ratio of the polyamide is lowered to lower the unit cost. However, There is a problem of breaking.

Also, if the blending ratio of polyamide is increased, ductility is increased and it is not broken well, but there is a problem that the manufacturing cost of polyamide increases.

Accordingly, it is most preferable to mix 50 wt% of the lozenge and 50 wt% of the polyamide, and this can be varied in various mixing ratios to facilitate those skilled in the art.

A step of mixing a block of clay with a polyamide, injecting the mixture into a high-temperature film extruder, extruding a film having a predetermined thickness and thickness, and supplying the extruded film to a stretching machine to lower the linear density, And a detailed description thereof will be omitted.

The nylon yarn produced as described above is used for the inclusions 30 to improve the flame retardancy and heat resistance and to prevent the generation of harmful substances upon combustion.

In addition, since it is much lower in cost than conventional rubber and polypropylene, and has better flame retardancy and heat resistance, it is economical and efficient.

The binder tape 40 is formed to enclose the inclusions 30 and may be formed of nylon yarn such as the inclusions 30.

When the inclusion 30 and the binder tape 40 are formed of nylon yarn and the sheath 50 is peeled off due to an external impact on the cable 1 the burnt material 30 and the binder tape 40 are burnt The harmful substances are not generated and the combustion incidence can be lowered.

The sheath 50 is formed so as to surround the binder tape 40, and may be formed of polyolefin.

Here, the polyolefin forming the sheath 50 may include an ethylene ethyl acrylate copolymer, an ethylene vinyl acetate copolymer, polyethylene, magnesium hydroxide, and carbon black.

Ethylene Ethyl Acrylate Copolymer (EEA) is one of the base resins of cis-poly (50) polyolefin, which shows high flexibility and is a copolymer of ethylene and ethyl acrylate.

The ethylene ethyl acrylate copolymer (EEA) may contain 20 to 30% by weight, and most preferably 25% by weight.

At this time, if the ethylene ethyl acrylate copolymer is less than 20% by weight, the effect of reducing the generation of harmful substances is insignificant, and if it exceeds 30% by weight, the physical properties of the sheath 50 may be deteriorated.

Ethylene Vinyl Acetate Copolymer (EVA) is one of the base resins of cis-50 polyolefin. It is a copolymer of ethylene and vinyl acetate and has high mechanical strength and excellent abrasion resistance.

Here, the ethylene vinyl acetate copolymer (EVA) has a linear polymerization structure, and can be linearly polymerized by polymerizing ethylene with vinyl acetate.

Accordingly, flexibility of the sheath 50 can be improved, and damage and breakage of the cable can be reduced by improving the flexibility.

Such an ethylene vinyl acetate copolymer may contain 5 to 15% by weight, most preferably 10% by weight.

If the content of the ethylene vinyl acetate copolymer is less than 5% by weight, the extrudability and flexibility may be deteriorated. If the ethylene vinyl acetate copolymer is more than 15% by weight, the mechanical properties may be deteriorated.

Polyethylene is one of the base resins of cis-poly (50) polyolefin, and one or more of low density polyethylene, medium density polyethylene, high density polyethylene and linear low density polyethylene can be mixed and used. Such polyethylene improves compatibility between various resins having different polarities and magnesium hydroxide, thereby enhancing the interfacial bonding force, improving the mechanical strength and increasing the filling property of magnesium hydroxide.

In addition, 10 to 20% by weight of polyethylene may be contained, and 15% by weight is most preferable.

If the amount of polyethylene is less than 10% by weight, the effect of improving the mechanical strength and filling property is insignificant. If the amount of polyethylene is more than 20% by weight, the interfacial bonding force becomes too strong,

Magnesium hydroxide is an inorganic flame retardant and is incorporated in the sheath 50 to improve the flame retardancy and heat-sealability.

Such magnesium hydroxide may include 40 to 50 wt%, most preferably 45 wt%.

If the amount of the magnesium hydroxide is less than 40% by weight, the flame retardancy and the heat-sealability may be deteriorated, and the rate of generation of harmful substances and the rate of smoke generation may be increased, and if it exceeds 50% by weight, abrasion resistance and mechanical properties may be deteriorated.

The carbon black can be incorporated in the sheath 50 to improve heat resistance and oil resistance, and it is possible to prevent the coloration of the sheath 50 as the skin layer.

Such carbon black may be contained in an amount of 1 to 3% by weight, and most preferably 2% by weight.

If the content of carbon black is less than 1% by weight, the effect of improving heat resistance and oil resistance is insignificant. If the content is more than 3% by weight, there is a problem in stability and viscosity and physical properties may be lowered.

Further, the polyolefin of the sheath 50 may further include an additive.

Additives are antioxidants. A wax, a deterioration inhibitor, a colorant, a crosslinking aid, a tackifier, a lubricant, a softener, a filler and a processing aid, and various additives may be used.

The additive may comprise from 2 to 4% by weight, most preferably 3% by weight.

Referring to FIG. 2, the power cable 1 according to the first embodiment of the present invention may further include a coating layer 60.

The coating layer 60 is coated on the surface of the sheath 50 to improve the abrasion resistance, heat resistance and corrosion resistance of the cable 1, and can be eco-friendly.

Such a coating layer 60 may comprise a mixture of a silane compound and a silica sol and a reinforcing agent.

The mixture of the silane compound and the silica sol may be produced by mixing the silane compound and the silica sol.

The silane compound is preferably at least one compound selected from the group consisting of methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, One of heptadecafluorodecyltrimethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, trifluoropropyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, tratethoxysilane, or heptadecafluorodecyltrimethoxysilane. Or a mixture of two or more.

The silica sol is a solution of ultrafine particles having a particle diameter of 10 to 20 占 퐉, and may be a mixture of 25 to 35% by weight of silica and 65 to 75% by weight of distilled water.

The mixture may be prepared by mixing 50 to 60% by weight of the silane compound and 40 to 50% by weight of the silica sol.

The mixture of the silane compound and the silica sol is most preferably 70 to 75 parts by weight based on 100 parts by weight of the coating layer 60.

The reinforcing agent can improve the durability, abrasion resistance, and corrosion resistance of the coating layer 60.

Such reinforcing agents may include one or more of potassium titanate, alumina, quartz-mononite, gneiss, rhyolite, tuff, seaweed, and charcoal.

Most preferably, the reinforcing agent is contained in an amount of 25 to 35 parts by weight based on 100 parts by weight of the coating layer (60).

The coating layer 60 is coated on the sheath 50 of the cable 1 to improve the durability, abrasion resistance, and corrosion resistance of the cable 1 and to prevent the cable 1 from easily burning or melting due to fire or the like. can do.

In addition, since harmful substances are not generated during combustion, they are harmless to the human body and can be environmentally friendly.

As described above, the power cable according to the embodiment of the present invention constitutes an insulator and a sheath formed of polyolefin, and the insulator and the inclusions are replaced by a material having enhanced flame retardancy and low toxicity, so that heat resistance is excellent, Can be improved.

Also, harmful substances generated when the sheath is peeled and burned by an external impact can be minimized.

Hereinafter, the present invention will be described in more detail with reference to Examples.

However, the following examples are illustrative of the present invention, and the contents of the present invention are not limited by the following examples.

[ Example  One]

Example 1 has a structure as shown in Fig. 1, and a power cable was manufactured according to Example 1 of Table 1 below.

Composition Example 1 (% by weight) Conductor copper 100 Insulator Polyethylene copolymer 40 Magnesium hydroxide 55 Trimethoxyvinylsilane 2 Antioxidant 3 Inclusion Nylon Company 100 Videotape Nylon Company 100 Cis Ethylene ethyl acrylate copolymer 25 Ethylene vinyl acetate copolymer 13 Polyethylene 15 Magnesium hydroxide 45 Carbon black 2

[ Example  2]

Compared with Example 1 above, the rest were the same except that a coating layer was formed by mixing and coating 70 parts by weight of a mixture of silane compound and silica sol and 30 parts by weight of rhyolite as a reinforcing agent on the outer circumferential surface of the sheath.

[ Comparative Example  One]

The conductor was made of copper, the insulator was made of crosslinked polyethylene, the inclusion was made of polypropylene, and the binder tape was made of crosslinked polypropylene, and the sheath was produced in the same manner as in Example 1.

[ Comparative Example  2]

Compared with Example 1, the same procedure as that of Example 1 was conducted except that magnesium hydroxide in the sheath was 30 wt%.

[ Comparative Example  3]

Compared with Example 1, the same was prepared except that the ethylene ethyl acrylate content of the sheath was 40% by weight, the ethylene vinyl acetate copolymer content was 25% by weight, and the polyethylene content was 7% by weight.

[ Experimental Example ]

The smoke density, toxicity index, flame retardancy, heat resistance, tensile strength and abrasion resistance of the power cables prepared in Examples 1 and 2 and Comparative Examples 1 to 3 were measured and the results of Examples 1 and 2 and Comparative Examples 1 to 3 Are shown in Table 2 below.

- The smoke density shall be measured in accordance with IEC 61034,

- Toxicity index according to NEC 711

- The flame retardancy is tested according to IEC 332-3C flame retardant test

- Heat resistance is tested according to ISO 6722.7

- Tensile strength is determined according to ASTM D638

- The abrasion resistance is measured by the number of reciprocations of the needle (ISO 6722.5-1) from the scratching needle to the electrical connection of the needle and the conductor until the machine is stopped. Judgment)

Example Comparative Example One 2 One 2 3 Smoke density (Dm) 80 82 230 205 120 Toxicity index 0.92 0.91 2.3 2.2 1.2 Flammability (cm) 75 70 150 100 95 Heat resistance Crack No Crack No Crack No Crack No Crack No The tensile strength
(kgf / mm2) 1.23 1.30 1.15 1.1 0.8 Abrasion resistance pass pass pass pass fail

As can be seen from Table 2, Examples 1 and 2 of the present invention have lower smoke density and toxicity index than Comparative Examples 1 to 3, and are excellent in flame retardancy, heat resistance, tensile strength and abrasion resistance.

Accordingly, the power cable of the present invention is excellent in low toxicity, flame retardancy, heat resistance and abrasion resistance, and minimizes harmful substances generated when it is peeled and burnt.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. The embodiments described above are therefore to be considered in all respects as illustrative and not restrictive.

1: Cable
10: Conductor
20: Insulator
30: inclusions
40: Binder tape
50: Cis
60: Coating layer

Claims (11)

In a power cable,
One or more conductors;
An insulator formed of polyolefin to surround the conductor;
An inclusion formed so as to surround the insulator;
A binder tape formed to surround the inclusion and
And a sheath formed of polyolefin to wrap the binder tape,
The inclusions and the binder tape may be,
A nylon yarn which is a film formed by extruding a mixture of a lozenge and a polyamide,
The polyolefin of the above-
35 to 45% by weight of a polyethylene copolymer, 50 to 60% by weight of magnesium hydroxide, 1 to 3% by weight of trimethoxyvinylsilane and 2 to 4% by weight of an antioxidant,
The polyolefin of the sheath,
Characterized in that it comprises 20 to 30% by weight of ethylene ethyl acrylate copolymer, 5 to 15% by weight of ethylene vinyl acetate copolymer, 10 to 20% by weight of polyethylene, 40 to 50% by weight of magnesium hydroxide and 1 to 3% .
The method according to claim 1,
In the nylon yarn,
Wherein 10 to 90% by weight of the abrasive grains and 10 to 90% by weight of the polyamide are mixed.
The method according to claim 1,
The above-
Characterized in that the resin is mixed with the stone powder having a particle size of 2,000 to 5,000 mesh and formed into a size of 2 to 5 mm.
delete delete The method according to claim 1,
The trimethoxyvinylsilane may be, for example,
Wherein the methoxy group is hydrolyzed.
The method according to claim 1,
Wherein the antioxidant is a mixture of propyl gallate, butalitate, hardoxytoluene, sodium gluconate, and limestone.
delete delete The method according to claim 1,
The ethylene vinyl acetate copolymer may contain,
And a linear polymerized structure.
The method according to claim 1,
The power cable includes:
And a coating layer formed on the surface of the sheath,
Wherein the coating layer comprises:
A mixture of a silane compound and a silica sol, and a reinforcing agent.

Images