KR101480009B1 - Semi-conductive compound for ultra-high voltage power cables and ultra-high voltage power cables using thereof - Google Patents

Abstract

The present invention relates to a semiconductive compound for a high-voltage or ultra-high-voltage power cable capable of suppressing the occurrence of surface protrusions and suppressing breakdown of an insulation layer, and an ultra-high-voltage power cable using the same. More specifically, a master batch comprising an ethylenic copolymer and a nano-carbon filler; Polyethylene; And an additive, wherein the ethylenic copolymer and the polyethylene are blended to form a polymer matrix, and a method for producing the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a semiconductive compound for a high-voltage or ultra-high-voltage power cable, and an ultra-high-voltage power cable using the same. BACKGROUND ART [0002]

TECHNICAL FIELD The present invention relates to semi-conductive compound materials used in high-voltage or ultra-high-voltage power cables capable of suppressing the occurrence of surface protrusions and suppressing breakdown of an insulation layer, and an ultra-high-voltage power cable using the semi-conductive compound materials.

The high-voltage or ultra-high-voltage power cable is composed of a conductor, a three-layer polymer coating layer, a metal shielding layer, and a method layer, and the three-layer polymer coating layer is composed of an inner semiconductive layer, an insulating layer and an outer semiconductive layer.

The inner and outer semiconductive layers (hereinafter referred to as semiconductive layers) serve to mitigate the electric field concentration caused by the spikes of the stranded metal conductors represented by copper and to prevent the dielectric breakdown of the insulating layers due to the electric field concentration. The method of applying conductive carbon black is used, and particularly, the addition of a large amount of 30 to 40% by weight is required to exhibit a semi-conductive property. However, a large amount of carbon black necessarily causes agglomeration due to the secondary bonding inherent to the nanoparticles, so that when the power cable is produced by the extrusion process, it tends to appear as protrusions on the surface of the semiconductive layer, It is difficult to secure or control surface smoothness. In addition, the protrusions formed on the surface of the semiconductive layer serve to concentrate the electric field, thereby inducing dielectric breakdown of the insulating layer composed of crosslinked polyethylene. Therefore, it is important to suppress the occurrence of protrusions on the surface of the semiconductive layer in order to suppress the insulation breakdown of the insulation layer. In the present technology, since the thickness of the insulation layer is increased to suppress insulation breakdown, the cable diameter increases Not only deteriorates the quality and construction competitiveness of cable, but also causes various problems such as obstacles to entry into the world market.

On the other hand, in order to disperse nanocarbon materials such as carbon black, an auxiliary material such as a surfactant is used. However, a surfactant having a small molecular weight acts as an impurity and ultimately induces dielectric breakdown of the insulating layer Do not use it. In recent years, attempts have been made to apply a hybrid type filler in which carbon black and carbon nanotubes (European Patent No. 0360238 and U.S. Patent No. 7390970) are mixed to reduce the content of nano-carbon and improve the characteristics of the semiconductive layer, It is not easy to secure the dispersibility of the carbon nanotubes and it is difficult to suppress the occurrence of surface protrusions due to the agglomeration phenomenon of the nanocarbon filler and it is difficult to secure the uniformity of dispersion of the nanocarbon filler, .

The present invention relates to a method of manufacturing a power cable, which is capable of minimizing the content of a nano-carbon filler for application to a compound for use in the production of a semiconductive layer of a power cable and dispersing the nanocarbon particles as uniformly as possible, It is possible to suppress the degree of nonuniformity and suppress the occurrence of protrusions on the surface of the semiconductive layer, thereby alleviating the electric field of the electric cable, and in particular, it is not necessary to modify the surface of the nano- Which is excellent in properties such as low resistance, high dispersion uniformity, and suppression of occurrence of surface projections, which can be avoided.

The present invention also provides a semiconductive compound and a method for producing the semiconductive compound, which are applied in the form of a master batch in which nano-carbon is melt-mixed with an ethylenic copolymer during the production of the semiconductive compound.

The present invention also provides an ultra-high voltage power cable device using the semi-conductive compound.

In order to achieve the above object,

A masterbatch comprising a high-pressure or ultra-high-pressure power ethylenic copolymer and a nano-carbon filler;

Polyethylene; And

An additive;

The ethylenic copolymer and polyethylene are blended to provide a semiconductive compound for the cable in which the polymer matrix is formed.

The master batch may be prepared by melt-kneading an ethylenic copolymer and a nano-carbon filler in a biaxial extruder.

Also, the compound may contain 50 to 96% by weight of an ethylene-based copolymer, 1.5 to 40% by weight of polyethylene, 2 to 10% by weight of a nano-carbon filler; And 0.5 to 3 wt% of an additive.

It is more preferable that the nano-carbon filler is contained in an amount of 3 to 7% by weight based on the total weight of the total compound.

The ethylenic copolymer may be selected from the group consisting of ethylene-co-ethyl acrylate (co), ethylene (co-methyl acrylate) and ethylene- (Poly (ethylene-co-butyl acrylate)).

Further, in the compound of the present invention, the content of the comonomer of ethyl acrylate, methyl acrylate or butyl acrylate in the blend as measured by nuclear magnetic resonance method is 4.5 wt% or more based on the weight of the total compound .

The nano-carbon filler may be a carbon nanotube, a carbon nanoplate, or a mixture thereof.

Wherein the weight ratio of the carbon nanotubes to the carbon nanoplate is 1: 4 to 5: 0.

The additive may be at least one selected from the group consisting of an antioxidant, a crosslinking agent, a dispersant, a lubricant, and an antioxidant.

In addition,

(a) melt-mixing a nano-carbon filler and an ethylenic copolymer to prepare a master batch; And

(b) melt mixing the masterbatch with polyethylene and an additive to form a compound;

Conductive compound for a power cable.

The compound obtained in the step (b) may be extruded from a twin-screw extruder and pelletized by impregnating or non-impregnating the cross-linking agent.

The present invention also relates to a cable comprising a conductor, an inner semiconductive layer, an insulating layer and an outer semiconductive layer, wherein the semiconductive compound for power cable is applied to the inner semiconductive layer and the outer semiconductive layer, Or an ultra high voltage power cable.

According to the present invention, a blend of a specific ethylene copolymer and a polyethylene having a comonomer content of ethyl acrylate, methyl acrylate, and butyl acrylate controlled to not less than 4.5% by weight is used as a matrix and a nano- Even when filled at 2 to 10 wt%, it is possible to achieve a low electrical resistance that can be obtained only by charging a large amount of conventional carbon black, which is close to 30 to 40 wt%.

Further, the semiconductive compound of the present invention can easily achieve the dispersion uniformity without needing to modify the surface of the nano-carbon or disperse the nano-carbon or acid treatment. Further, since the present invention uses a small amount of nano-carbon as a filler, the surface protrusion of the power cable semiconductive layer produced by the present invention can also be suppressed, so that the insulation breakdown of the insulating layer made of crosslinked polyethylene is extremely suppressed can do. Therefore, the compound of the present invention is not only very useful as a semi-conductive compound for producing a semiconductive layer for an ultra-high voltage power cable, but also can provide a semiconductive layer suitable as a highly reliable high-voltage cable device.

Fig. 1 shows the specimen (100 mm * 100 mm) divided into 13 places to measure the dispersion uniformity of the compound.

Hereinafter, the present invention will be described in detail.

Disclosed is a semi-conductive compound for a power cable comprising a polymer matrix, a nano-carbon filler and an antioxidant. The nano-carbon filler can be easily dispersed and uniformly dispersed, To a semi-conducting compound capable of preventing dielectric breakdown of an insulating layer typified by crosslinked polyethylene and an ultra high-voltage power cable device using the same.

According to one embodiment of the invention, a masterbatch comprising an ethylenic copolymer and a nano-carbon filler; Polyethylene; And an additive, wherein the ethylenic copolymer and polyethylene are blended to form a polymer matrix, wherein the semiconductive compound for high voltage or ultra high voltage power cable is provided.

In the semiconductive compound of the present invention, the nano-carbon filler has a low electrical resistance which can be obtained only by charging a conventional carbon black to a content of about 30 to 40% by weight, even if a relatively small amount of the conventional carbon black is used. . In addition, in the present invention, the nano-carbon filler is evenly dispersed in the compound, so that protrusion of the surface can be suppressed.

Such a compound of the present invention comprises 50 to 96% by weight of an ethylenic copolymer, 1.5 to 40% by weight of polyethylene, 2 to 10% by weight of a nano-carbon filler; And 0.5 to 3 wt% of an additive.

The semiconductive compound for high-voltage or ultra-high voltage cables of the present invention is characterized by applying a blend of an ethylene copolymer and polyethylene, wherein the comonomer content of ethyl acrylate, methyl acrylate, or butyl acrylate in the blend is By weight or more and 4.5% by weight or more.

The ethylenic copolymer may be selected from the group consisting of ethylene-co-ethyl acrylate (co), ethylene (co-methyl acrylate) and ethylene- Poly (ethylene-co-butyl acrylate)) is preferably used. More preferably, the ethylene copolymer may be at least one selected from the group consisting of compounds represented by the following formulas (1) to (3). Thus, in the ethylene copolymer, the comonomers of ethyl acrylate, methyl acrylate and butyl acrylate refer to repeating units represented by the repeating units n, q, and y in the formulas (1) to (3).

[Chemical Formula 1]

(Wherein m is 80 to 90% by weight and n is 20 to 10% by weight in the formula (1)

(2)

(Where p is from 70 to 80% by weight and q is from 30 to 20% by weight in the formula (2)

(3)

(X is 70 to 85% by weight and y is 30 to 15% by weight in the formula (3)

Also, the content of the comonomer of ethyl acrylate, methyl acrylate, or butyl acrylate in the blend may be greater than or equal to 4.5% by weight, based on the weight of the total compound, as measured by nuclear magnetic resonance (NMR). At this time, when the content of the comonomer is 4.5 wt% or less, it is difficult to achieve the dispersion uniformity of the nano-carbon used as a filler.

At this time, the content of the ethylenic copolymer is preferably 50 to 96% by weight, more preferably 60 to 80% by weight, based on the total weight of the total compound. When the content of the ethylenic copolymer is less than 50% by weight, there is a problem that the nano-carbon is not uniformly dispersed. When the content of the ethylenic copolymer is more than 96% by weight, the dispersing effect by polyethylene is reduced and the dispersion uniformity of the nano- .

In addition, the content of the polyethylene is preferably 1.5 to 40% by weight, more preferably 10 to 35% by weight based on the total weight of the total compound. If the content of the polyethylene is less than 1.5% by weight, the effect of blending the polyethylene is reduced. If the content of the polyethylene exceeds 40% by weight, the blending effect is also decreased and it is difficult to ensure uniformity of dispersion, .

The polyethylene may be conventional ones. The kind of the polyethylene is not particularly limited, but it is preferable to use polyethylene having a melt flow index (MI) of 3 to 8 g / 10 min and a weight average molecular weight of 60,000 to 200,000 desirable.

In the present invention, the nano-carbon filler may be carbon nanotubes, carbon nano-plates, or mixtures thereof.

In addition, it is preferable that the nano-carbon filler is not mixed at the time of preparing the compound, but is pre-kneaded with the ethylenic copolymer and applied in the form of a master batch. Such a master batch can be provided as a compound in which the polymer matrix in which the ethylenic copolymer and the polyethylene are blended and the nano-carbon are evenly dispersed by being mixed with the polyethylene and the additive in the melt. If the nano-carbon filler is not used in the form of a master batch which is mixed at one time during the compund production or kneaded with the ethylenic copolymer, it is difficult to secure uniformity of dispersion and the occurrence of surface protrusions may be difficult to suppress .

The above-described carbon nanotubes are advantageous in that the conventional multi-walled carbon nanotubes are easy to attain dispersibility as well as good dispersion uniformity and are cost-effective. The carbon nanoplate having a layered structure is most preferably a single layer referred to as graphene. However, since it can not be easily produced and easily dispersed, it is preferable to use a carbon nanoplate having a thickness of 100 nm or less . When the carbon nanotubes are mixed with the carbon nanotubes, the content of the carbon nanotubes may be greater than the carbon nanotubes. Therefore, the weight ratio of the carbon nanotubes to the carbon nanoplate is used in a ratio of 1: 4 to 5: 0, more preferably 3: 2 to 5: 0.

The nano-carbon filler may be used in an amount of 2 to 10 wt%, more preferably 3 to 7 wt%, based on the total weight of the total compound. When the content of the nano-carbon filler is less than 2% by weight, there is a problem that the volume resistivity is high and the semiconductive property can not be secured. When the content is more than 10% by weight, the dispersibility can not be secured due to the excessive amount of the nano- There is a problem that it is difficult to suppress the occurrence of projections.

In the present invention, the additive may be at least one selected from the group consisting of an antioxidant, a crosslinking agent, a dispersant, a lubricant and an antioxidant. The content of the additive may be 0.5 to 3 wt%, more preferably 0.5 to 1.5 wt%, based on the total weight of the total compound.

The antioxidant in the present invention is not particularly limited as long as it is used in the production of semiconducting compounds for general power cables. However, it is preferable to mix phosphorus-based antioxidant with a conventional phenolic antioxidant. The cross-linking agent may be either an organic peroxide or an azo compound, or both, which are conventionally used in the production of semiconducting compounds for electric power cables.

Meanwhile, according to the present invention, an interfacial bonding agent can be further used as needed.

That is, since the nano-carbon is an inorganic material having poor interfacial bonding with the polymer matrix, it is preferable to use a silane-based interface binder in order to improve the interfacial bonding strength and ultimately to improve the mechanical properties. However, since the interfacial bond easily functions as an impurity, it is preferable to limit the amount thereof to a minimum. The interfacial bonding agent can be classified into an epoxy type, an amine type, a vinyl type, and the like, which have reactive end groups and have no reactivity. In the present invention, it is preferable to use an epoxy-based or non-reactive interfacial binder in an amount of 0.5 to 1.5 parts by weight based on the weight of the nano-carbon filler.

According to another embodiment of the present invention, there is provided a process for producing a master batch, comprising: (a) melt-mixing a nano-carbon filler and an ethylenic copolymer to prepare a master batch; And (b) melt mixing the master batch with polyethylene and additives to produce a compound. A method of making a semiconductive compound for a power cable is provided.

The use of a blend of an ethylene copolymer and polyethylene in the present invention is a method capable of effectively dispersing a nano-carbon filler. When the content of the comonomer in the blend is not less than 4.5 wt% regardless of the respective melt flow indexes or melting points, By effectively dispersing the filler, a low nanocarbon content can ensure low electrical resistance and uniformity of dispersion required as a semi-conductive compound.

To this end, in the present invention, a master batch obtained by previously dispersing a nano-carbon filler in an ethylene copolymer is used, and it is easy to attain the excellent dispersion uniformity of the nano-carbon by melting and mixing the master batch with polyethylene. In addition, in the present invention, since the effectively dispersed nanocarbon filler does not act as a protrusion on the surface of the semi-conductive compound, the dielectric breakdown can be prevented in advance.

In addition, since nano-carbon materials contain impurity carbon represented by amorphous carbon, they may be removed through heat treatment. In this case, it is preferable to apply a temperature of 700 캜 or higher in a nitrogen atmosphere in the production of the compound.

In the present invention, a usual method can be used for producing a compound, except that the above-mentioned master batch is used. Therefore, a twin-screw extruder can be used for compounding, and the conditions are not particularly limited.

In the present invention, the compound obtained in the step (b) may be further extruded in a biaxial extruder and pelletized by impregnating or non-impregnating the cross-linking agent. The pellets thus produced can be used for characterization.

According to still another embodiment of the present invention, there is provided a cable including a conductor, an inner semiconductive layer, an insulating layer, and an outer semiconductive layer, wherein the semiconductive compound for the power cable is applied to the inner semiconductive layer and the outer semiconductive layer A high-voltage or ultra-high-voltage power cable is provided.

No special apparatus or equipment is required for producing the semiconductive compound for an ultra-high voltage cable using the compound composition of the present invention, and the conventional manufacturing method well known in the technical field of the present invention can be used without limitation . Therefore, detailed description of the power cable in the present invention will be omitted.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. However, the following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited to these examples.

≪ Examples 1 to 8 &

The semi-conducting compounds of Examples 1 to 8 were prepared with the compositions and conditions shown in Table 1 below.

That is, compounding was performed using a twin-screw extruder having a diameter of 11 mm and a length-to-diameter ratio of 40/11, and the temperature of the barrel was maintained at 120 ° C to 140 ° C. In order to control the content in the copolymer and ensure uniformity of dispersion, a masterbatch prepared by melt kneading ethylene copolymer and nano-carbon was applied. The extruded compound was pelletized without impregnation with a crosslinking agent, .

Character rating

The properties of the semi-conducting compound were evaluated by measuring the volume resistivity, the uniformity of dispersion of the surface resistance, the surface projection, and the tensile strength in the following manner.

(1) Copolymer content

Was measured using a Nuclear Magnetic Resonance Spectrometer (NMR).

(2) Volumetric resistance and uniformity of dispersion

In order to evaluate the volume resistivity and the uniformity of the dispersion, the specimen was prepared by compressing a sheet type specimen having a side length of 10 cm and a thickness of 1 mm.

First, the uniformity of dispersion was measured by dividing into 13 areas as shown in FIG. 1 using the following equation, and the average value of three specimens was taken.

[Equation 1]

Dispersion uniformity (%) =

Here, R _i is the measured value of each of 13, R ₀ is the average value of 13, and n means 13 as the number of times of measurement.

The volume resistivity was measured using a 4-point probe method.

(3) surface projection

The specimens for surface protrusion measurement were fabricated on a tape of 1 mm in thickness and 10 cm in width using a T-shaped die of a small extruder. The number of protrusions in the area of 10 × 30 cm ² was measured using an optical microscope. Only the protrusions having a maximum diameter and a height of 50 mm or more and 30 mm or more were measured.

(4) Tensile strength and elongation

Tensile strength and elongation were measured using a dumbbell specimen as shown in ASTM D 638.

In this case, the electrical characteristics were the average of the three specimen measurements and the tensile strength was the average of the five specimen measurements. All measurements were made after 1 hour of specimen preparation without special aging. The measurement atmosphere was measured at 90 ° C for volume resistance and 121 ° C for tensile properties. All other properties were measured at a temperature of 23 ± 2 ° C And 50 ± 5% RH, respectively.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8
¹⁾ Master
arrangement ²⁾ Ethylene Ethyl
Acrylate
Copolymer 57.6 67.2 76.8 66.5 65.8 66.5 65.8 - ³⁾ Ethylene butyl
Acrylate
Copolymer - - - - - - - 67.2 ⁴⁾ Carbon nanotubes 4.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 ⁵⁾ Carbon nano
Plate 1 - - - 1.0 2.0 - - - ⁶⁾ Carbon nano
Plate 2 - - - - - 1.0 2.0 - ⁷⁾ Polyethylene 38.4 28.8 19.2 28.5 28.2 28.5 28.2 28.8 ⁸⁾ Antioxidant 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Sum 100 100 100 100 100 100 100 100 Copolymer content (% by weight) 8.09 9.44 10.79 9.98 9.87 9.98 9.87 8.72 Volume Resistance (Wcm) 5.67 12.34 9.89 74.71 56.08 77.65 93.17 6.52 Dispersion uniformity (%) 90.45 91.64 93.57 93.46 94.07 90.98 94.71 90.55 Tensile strength (kg / mm2) 1.3 1.22 1.20 1.0 1.03 1.12 0.99 1.22 Elongation (%) 545 602 580 447 460 595 476 708 Surface projection (pieces / m2) 0 0 0 One 2 0 One 0

week)

1) Master batch: The master batch of the embodiment means that the ethylene copolymer and the nano-carbon filler are preliminarily dispersed using a twin-screw extruder. The compression conditions at this time are as described above.

2) Ethyl Ethyl Acrylate Copolymer: Elvaloy AC 2615 (DuPont)

3) Ethylene butyl acrylate copolymer: Lucofin 1400 MN (Lucobit)

4) Carbon nanotube: NC 7000 (manufactured by Nanocyl)

5) Carbon nanoplate 1: C-500 (manufactured by XG Science)

6) Carbon nanoplate 2: Treatment of C-500 with microwave for 1 minute

7) Polyethylene: SEETEC XL 600 (manufactured by Lotte Chemical)

8) Antioxidant: Irganox 1010 (phenolic antioxidant, Ciba)

From the results of Table 1, it can be seen that Examples 1 to 8 had a comonomer content of 4.5 wt% or more, excellent physical properties as a whole, little surface protrusions, and excellent dispersion uniformity. Therefore, the compound of the present invention can prevent dielectric breakdown in advance and can exhibit a low resistance, and is effective for application to a high-voltage or ultra-high-voltage power cable.

< Example  9 to 12 and Comparative Example  1 to 4>

Nano carbon nanotubes were fixed at one kind and constant contents, and another carbon nanoplate 3 and 4 were used. The effects of the ethylene copolymer-polyethylene blend and the copolymer content in the ethylene copolymer, and the use of the master batch, etc., proposed in the present invention, on the properties of the compound were compared. Table 2 shows the compositions and properties of each of the semi-conducting compounds.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 9 Example 10 Example 11 Example 12 Ethylene ethyl
Acrylate 95 94 95 94 66.5 65.8 66.5 65.8 Carbon nanotube 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 ⁹⁾ Carbon nanoplate 3 1.0 2.0 - - 1.0 2.0 - - ¹⁰⁾ Carbon nanoplate 4 - - 1.0 2.0 - - 1.0 2.0 Polyethylene - - - - 28.5 28.2 28.5 28.2 Antioxidant 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Master batch application ingredients Master batch not available Ethylene copolymer + nano-carbon Copolymer content (% by weight) 13.35 13.21 13.35 13.21 9.98 9.87 9.98 9.87 Volume Resistance (Wcm) 4.98 4.11 10.70 11.09 73.56 39.47 94.79 75.55 Dispersion uniformity (%) 60.61 82.59 79.02 88.54 93.42 90.44 91.48 93.71 Tensile strength (kg / mm ² ) 0.79 0.75 1.11 1.12 0.95 0.79 0.92 0.82 Elongation (%) 278 134 745 717 355 168 438 327 Surface projection (pieces / m ² ) many many many many One 4 3 4

week)

9) Carbon nanoplate 3: M-5 (manufactured by XG Science)

10) Carbon nanoplate 4: Treatment of M-5 with microwave for 1 minute

From the results shown in Table 2, it was found that the master batches of the ethylene copolymer and the nano-carbon were not applied in Comparative Examples 1 to 4, and the problem that many surface protrusions were generated due to the absence of polyethylene as a blend occurred, and the dispersion uniformity was poor . On the other hand, in Examples 9 to 12, as in Examples 1 to 8 described above, there were almost no surface projections and the dispersion uniformity was excellent. Therefore, even when the carbon nanotubes or the carbon nanoplate are mixed, it can be understood that the insulation breakdown can not be prevented due to the surface projection problem unless the master batch is applied as well as the polymer blend composition according to the present invention.

&Lt; Comparative Examples 5 to 12 >

Compounds were prepared according to the compositions and conditions shown in Table 3 below.

In this comparative example, when the nano-carbon filler is applied only to an ethylene copolymer but not to a blend, a blend of an ethylene copolymer and polyethylene is used. When the content of the copolymer is 4.5 wt% or less, And the effect of the interface binder.

Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Comparative Example 11 Comparative Example 12 Ethylene ethyl
Acrylate 95 96 67.2 67.2 28.8 67.2 Carbon nanotube 4.0 3.0 3.0 3.0 3.0 3.0 ¹¹⁾ Amine terminal
Interfacial bonding agent - - - - - - 0.3 - ¹²⁾ Epoxy end
Interfacial bonding agent - - - - - - - 0.3 Polyethylene - - 28.8 28.8 67.2 28.8 - - Antioxidant 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
Master batch
Applicable components Master batch not available Polyethylene + Nano Carbon Ethylene copolymer + nano-carbon Ethylene copolymer + polyethylene Master batch not available Copolymer content
(weight%) 13.35 14.05 9.44 9.44 4.05 9.44 14.05 14.05 Volume Resistance (Wcm) 4.50 4.56 13.29 150.5 12.52 134.4 581.9 7.93 Dispersion uniformity (%) 68.52 73.74 70.12 60.20 78.66 63.22 57.46 84.94 Tensile strength (kg / mm ² ) 1.4 1.2 1.12 0.95 1.10 1.08 0.84 0.94 Elongation (%) 620 512 580 592 611 629 428 560 Surface projection (pieces / m ² ) 12 25 18 15 many many 24 5

week)

11) Amine terminal interface binder: KBM-603 (3-glycidoxypropyltriethoxysilane, Shin-Etsu)

12) Epoxy end interface binder: KBM-403 (N-2 (aminoethyl) 3-aminopropyltriethoxy silane, manufactured by Shin-Etsu)

As shown in Table 3, Comparative Examples 5 to 7, 11 and 12 had a copolymer content of 4.5 wt% or more, but surface protrusions occurred due to the absence of the master batch of the present invention and the dispersion uniformity was low. In Comparative Example 8, the uniformity of the dispersion was further lowered by applying the polyethylene and the nano-carbon filler to the master batch, and surface protrusions were also generated. In Comparative Example 9, although the composition of the ethylenic copolymer and the nano-carbon filler was applied as a master batch as in the present invention, the content of the ethylenic copolymer was so low that the content of polyethylene was relatively increased, And the dispersion uniformity was also low. In Comparative Example 10, since the master batch in which the ethylenic copolymer and the polyethylene were premixed was used without using the nano-carbon, the dispersion uniformity was lowered and many surface projections were generated.

From these results, it was found that, when a semiconductive compound for a power cable is produced, a master batch in which an ethylenic copolymer and a nano-carbon filler are melt-blended in advance is applied, and the content range of the ethylenic copolymer is also specified within a certain range, Even if a small amount of nanocarbon such as a tube and a carbon nanoplate is filled in an amount of 2 to 10 wt%, a low electric resistance can be achieved. Further, according to the semi-conductive compound for an ultra-high voltage cable of the present invention, it is not necessary to modify the surface of the nano-carbon or disperse the nano-carbon to disperse the nano-carbon, and dispersion uniformity can be easily achieved. Therefore, the semiconductive layer of the power cable manufactured according to the present invention can prevent the insulation breakdown of the insulating layer formed of the crosslinked polyethylene because the surface projection is not generated.

Claims (12)

A masterbatch comprising an ethylenic copolymer and a nano-carbon filler;
Polyethylene; And
An additive;
The ethylenic copolymer and the polyethylene are blended to form a polymer matrix,
The ethylenic copolymer may be selected from the group consisting of ethylene-co-ethyl acrylate (co), ethylene (co-methyl acrylate) and ethylene- Poly (ethylene-co-butyl acrylate), and the like.
The content of ethyl acrylate, methyl acrylate or butyl acrylate comonomer in the blend as measured by nuclear magnetic resonance method is not less than 4.5% by weight based on the total weight of the compound, Compound.
The method according to claim 1,
Wherein the masterbatch is produced by melt-kneading an ethylenic copolymer and a nano-carbon filler in a biaxial extruder to produce a semiconductive compound for a high-voltage or ultra-high-voltage power cable.
The method according to claim 1,
50 to 96% by weight of an ethylene-based copolymer,
1.5 to 40% by weight of polyethylene,
2 to 10% by weight of a nano-carbon filler; And
0.5 to 3 wt.% Of an additive; and a semiconductive compound for a high-voltage or ultra-high voltage power cable.
The method according to claim 1,
Wherein the nano-carbon filler comprises from 3 to 7% by weight, based on the total weight of the total compound, of a semiconductive compound for a high-voltage or ultra-high voltage power cable.
delete delete The semiconductive compound of claim 1, wherein the nano-carbon filler is a carbon nanotube, a carbon nanoplate, or a mixture thereof, for a high-voltage or ultra-high-voltage power cable.
8. The method of claim 7,
Wherein the weight ratio of the carbon nanotube to the carbon nanoplate is 1: 4 to 5: 0.
The method according to claim 1,
Wherein the additive is at least one selected from the group consisting of an antioxidant, a crosslinking agent, a dispersant, a lubricant, and an antioxidant, and a semiconductive compound for a high-voltage or ultra-high-voltage power cable.
(a) melt-mixing a nano-carbon filler and an ethylenic copolymer to prepare a master batch; And
(b) melt mixing the masterbatch with polyethylene and an additive to produce a compound,
Further comprising the step of extruding the compound obtained in step (b) in a twin-screw extruder and impregnating or non-impregnating the cross-linking agent to pelletize the cross-linked compound.
delete 1. A high-voltage or ultra-high-voltage power cable comprising a conductor, an inner semiconductive layer, an insulating layer and an outer semiconductive layer,
A semi-conductive compound for a high-voltage or ultra-high-voltage power cable according to any one of claims 1 to 4, 7, or 9 is applied to the inner semiconductive layer and the outer semiconductive layer, cable.

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