KR101942790B1 - Semi-Conductive Layer Composition for Distributing Cable and Eco-Friendly Distributing Cable - Google Patents

Abstract

The present invention relates to a semi-conductive layer composition for a distribution cable and an eco-friendly distribution cable using the same and, more specifically, to a semi-conductive layer composition for a distribution cable, which fills a space between a conductor and an insulation layer or an insulation layer and a sheath layer and inhibits a partial electric discharge, and an eco-friendly distribution cable using the same. According to the present invention, an internal semi-conductive layer composition for a distribution cable contains polypropylene and thermoplastic polyolefin (TPO) as a base resin and an external semi-conductive layer composition contains polypropylene and ethylene-butyl acrylate (EBA) as a base resin. According to the semi-conductive layer composition for a distribution cable, a process can be simplified by eliminating a cross-linking process in a cable production process, the semi-conductive layer composition can be reused, and produced cable wire has thermal resistance equal to or greater than that of conventional cross-linked polyethylene (XLPE) and has excellent physical and electric properties required in a power cable.

Description

TECHNICAL FIELD [0001] The present invention relates to a semiconductive layer composition for a power distribution cable and an environmentally-

The present invention relates to a semiconductive layer composition for power distribution grade cables and an environmentally friendly power distribution cable using the same. More particularly, the present invention relates to a semi- conductor distribution layer composition for a power distribution grade cable which bridges a space between a conductor and an insulation layer or between an insulation layer and a sheath layer, Layer composition and an eco-friendly power distribution cable using the same.

A typical power cable includes a conductor and an insulating layer surrounding the conductor. In the case of a high-voltage or ultra-high voltage cable, an inner semiconductive layer between the conductor and the insulating layer, an outer semiconductive layer surrounding the insulating layer, a sheath layer surrounding the outer semiconductive layer As shown in FIG.

Power lines are divided into 10 ~ 66 kV for medium voltage (MV class), 66 ~ 230 kV for high voltage (HV class) and 230 kV or more for high voltage (EHV class) depending on voltage. Generally, The base resin of high heat resistance is required.

Semi-conductor materials for ultra-high-voltage electric power lines depend on imports due to high prices. Electrolytic ethylene acrylate (EEA) copolymers and ethylene butyl acrylate (EBA) copolymers are available for the superconducting layers used in ultra-high voltage power lines. These are copolymers of ethylene with an ethyl acrylate (EA) comonomer and a butyl acrylate (BA) comonomer, and generally have a low melting temperature (Tm) of 100 ° C or less. Also, in case of ultra-high voltage electric power line, since the constant use temperature is about 90 ° C. and the surge temperature is about 110 ° C., when the ethylene ethyl acrylate copolymer and the ethylene butyl acrylate copolymer are used for a long time, You may not be satisfied.

Korean Patent Registration No. 0907711 discloses a semiconductive composition for an ultra high voltage cable, which discloses a semiconductive composition in which a high purity high conductivity carbon black is added to ethylene ethyl acrylate. However, when the carbon black content is large relative to the base resin It is possible to cause insulation breakdown, increase the volume and weight of the power line, decrease the dispersibility between the base resin and the carbon black, and use the solution mixing method in the production, have.

In order to solve the problem caused by the use of such carbon black, Korean Patent No. 1408925 discloses a power cable including a semiconductive layer, wherein the semiconductive layer is composed of a carbon nanotube alone or a carbon black and a carbon black in a polyol- . However, the present invention does not disclose whether a design life of 30 years required for an ultra-high voltage electric power line can be secured, and satisfies such a long-term service life requirement You can not.

In order to solve the above problems, Korean Patent No. 1658309 discloses a resin composition comprising 6 to 8 parts by weight of carbon nanotubes, 0.5 to 3 parts by weight of graphene, 0.1 to 0.5 parts by weight of a primary antioxidant 0.01 to 0.08 part by weight of a secondary antioxidant, 0.4 to 1.2 parts by weight of a crosslinking agent, and 3 to 7 parts by weight of a processing aid.

However, since the crosslinked polyethylene (XLPE) or the like which has been used as the base resin constituting the semiconductive layer is in a crosslinked form, when the lifetime of a cable or the like including an insulating layer made of a resin such as the crosslinked polyethylene is shortened, The resin can not be recycled and it is not environmentally friendly because it can not be disposed of by incineration.

On the other hand, it can be considered to use an environment-friendly polypropylene resin as a base resin because it has excellent heat resistance without crosslinking at a melting point of the polymer itself of 160 캜 or higher. However, due to the insufficient flexibility and flexibility due to the high rigidity of the polypropylene resin, the workability of the cable including the semiconductive layer manufactured from the polypropylene resin is low, and the use thereof is limited there is a problem.

Accordingly, there is a demand for a new semiconductive layer and a power cable including the same, which are environmentally friendly, low in manufacturing cost, and capable of simultaneously satisfying tensile strength, elongation, heat resistance, volume resistivity and peel strength.

Accordingly, the present inventors have made efforts to solve the above problems, and as a result, they have found that an inner semiconductive layer composition containing polypropylene and thermoplastic polyolefin (TPO) as a base resin and an inner semiconductive layer composition comprising polypropylene, thermoplastic polyolefin (TPO) and ethylene butyl acrylate When an external semiconductive layer composition containing a base resin is used, it has heat resistance equal to or higher than that of conventional cross-linked polyethylene (XLPE), and can satisfy the physical and electrical characteristics required for electric power cables, It is possible to simplify the process. Thus, the present invention has been completed.

An object of the present invention is to provide an eco-friendly power distribution cable having heat resistance equal to or higher than that of conventional cross-linked polyethylene (XLPE) and satisfying the physical characteristics and electrical characteristics required for the power cable, and a semiconductive layer composition for power distribution cable have.

In order to achieve the above object, the present invention provides an inner semiconductive layer composition for distribution grade cables, which comprises polypropylene and a thermoplastic polyolefin (TPO) as a base resin.

In the present invention, the base resin is characterized by containing 80 to 90% by weight of polypropylene and 10 to 20% by weight of a thermoplastic polyolefin (TPO).

In the present invention, the inner semiconductive layer composition further comprises a conductive material, an antioxidant and a processing aid.

In the present invention, 50 to 60 parts by weight of a conductive material, 0.1 to 1 part by weight of an antioxidant and 0.1 to 2 parts by weight of a processing aid are added to 100 parts by weight of the base resin.

The present invention also provides an outer semiconductive layer composition for distribution grade cables characterized by containing polypropylene, thermoplastic polyolefin (TPO) and ethylene butyl acrylate (EBA) as a base resin.

In the present invention, the base resin is characterized by containing 20 to 30% by weight of polypropylene, 5 to 15% by weight of a thermoplastic polyolefin (TPO), and 60 to 70% by weight of ethylene butyl acrylate (EBA).

In the present invention, the outer semiconductive layer composition further comprises a conductive material, an antioxidant, a processing aid, and a dispersant.

In the present invention, it is characterized by comprising 50 to 60 parts by weight of a conductive material, 0.1 to 1 part by weight of an antioxidant, 0.1 to 2 parts by weight of a processing aid, and 3 to 7 parts by weight of a dispersant, based on 100 parts by weight of the base resin.

The present invention also provides a semiconductor device comprising a conductor, an inner semiconductive layer surrounding the conductor, and an inner semiconductive layer formed from an inner semiconductive layer composition containing polypropylene and thermoplastic polyolefin (TPO) as a base resin, (EN) An environment - friendly distribution grade cable characterized by being formed from a composition containing a thermoplastic polyolefin (TPO) and ethylene butyl acrylate (EBA) as a base resin.

When the semiconductive layer composition for power distribution cable according to the present invention is used, since the crosslinking is not performed during the cable manufacturing process, the process can be simplified and recycled. In addition, the produced cable wire can be produced by using conventional crosslinked polyethylene (XLPE) It has heat resistance equal to or higher than that of the power cable, and has excellent physical and electrical characteristics required for a power cable.

1 is a longitudinal sectional view showing a cross-sectional structure of a power cable manufactured according to an embodiment of the present invention.
FIG. 2 is an electron micrograph of a surface protrusion of an inner semiconductive layer specimen produced according to a comparative example of the present invention. FIG.
FIG. 3 is an electron micrograph of a protruded surface of an outer semiconductive layer specimen produced according to a comparative example of the present invention.

(A) an inner semiconductive layer composition containing polypropylene and a thermoplastic polyolefin (TPO) as a base resin or (b) an inner semiconductive layer composition containing polypropylene, a thermoplastic polyolefin (TPO) and a thermoplastic polyolefin When an external semiconductive layer composition containing ethylene butyl acrylate (EBA) as a base resin is used, a power cable having heat resistance equal to or higher than that of conventional crosslinked polyethylene (XLPE) and satisfying the physical characteristics and electrical characteristics required for the power cable And the like.

In the present invention, an inner semiconductive layer composition containing polypropylene and thermoplastic polyolefin (TPO) as a base resin was prepared and then extruded to prepare a test piece which can be used as an inner semiconductive layer for power distribution cable, and its physical properties were evaluated. As a result, it was confirmed that the physical properties such as tensile strength, elongation, heat resistance and volume resistivity were all excellent.

Accordingly, in one aspect, the present invention relates to an inner semiconductive layer composition for distribution grade cables characterized by containing polypropylene and a thermoplastic polyolefin (TPO) as a base resin.

In the present invention, the polypropylene may be any of random polypropylene, homopolypropylene, block polypropylene and the like as long as it can withstand the maximum permissible temperature of 110 to 120 ° C of the conductor. As described above, when a composition containing non-crosslinked polypropylene is used as the insulating material for forming the inner semiconductive layer, it is not necessary to undergo a crosslinking step separately, and the manufacturing cost can be reduced.

In the present invention, the thermoplastic polyolefin (TPO) is for imparting flexibility to the base resin, and is freely usable without any particular limitations as long as the above object can be achieved, and it is preferable to use a polypropylene copolymer.

The base resin may include 80 to 90% by weight of polypropylene and 10 to 20% by weight of a thermoplastic polyolefin (TPO).

When the upper limit value of the polypropylene or the lower limit value of the thermoplastic polyolefin (TPO) is less than the upper limit value of the thermoplastic polyolefin (TPO) or the lower limit value of the polypropylene, After the cable is compressed, there is a problem that the shrinkage occurs during the cooling process and the outside diameter can not be maintained.

The inner semiconductive layer composition for power distribution cable of the present invention may further comprise a conductive material, an antioxidant and a processing aid.

Examples of the conductive material include, but are not limited to, nickel, copper, silver, carbon, carbon nanotube (CNT), and graphite. The conductive material may be selected from the range of 50 to 60 parts by weight based on 100 parts by weight of the base resin. have. When the content of the conductive material is less than 50 parts by weight, the volume resistance is lowered and the standard value can not be satisfied. When the amount exceeds 60 parts by weight, the tensile strength and elongation are lowered, Can cause difficult problems.

The antioxidant may be at least one selected from the group consisting of phenol, phosphorus, amine, sulfur and metal. The antioxidant may be at least one selected from the group consisting of phenolic antioxidants Is preferably used. The phenolic antioxidants may be sterically hindered phenolic stabilizers, for example, alkylated monophenols, polyphenols or alkylation products of dienes and polyphenols, but are not limited thereto Do not. For example, 2,6-di-tetra-butyl-4-methylphenol, octadecyl-3- (3,5-di- Bis (4'-hydroxy-3'-t-butylphenyl) butanoic acid) glycol ester, tetrabis (methylene-3- (3,5- ) Methane, 1,2-bis (3,5-di-t-butyl-4-hydroxyhydrocinnamoyl) hydrazine ), 4,4'-thiobis (2-t-butyl-5-methylphenol), 2,2'-thiodiethylbis- [3- (3,5- Phenyl) -propionate], pentaerythrityl-tetrakis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate], 4,4'-thiobis Methyl-6-t-butylphenol), 2,2'-thiobis (6-t-butyl-4-methylphenol), triethylene glycol- Hydroxyphenyl) propionate], thiodiethylene bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 6,6'- Di-t-butyl-2,2'-thiodi-p-cresol, 1,3,5-tris (4-t- 5-triazine-2,4,6- (1H, 3H, 5H) -thione and dioctadecyl 3,3'-thiodipropionate can be used.

The antioxidant may be used in a range that does not impair the heat resistance while achieving the intended physical properties. Specifically, the antioxidant may be used in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the base resin.

The processing aid may be used in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of the base resin to improve moldability by suitably reducing hardness and maintaining flowability of the composition. If the content of the processing aid is less than 0.1 parts by weight, the effect of increasing the formability may not be expected. If the amount is more than 2 parts by weight, the mechanical properties may be deteriorated.

Examples of the processing aid include polyethylene wax, paraffin wax, paraffin oil, organic silicone, fatty acid ester compound, fatty acid amide compound, fatty acid alcohol, fatty acid, zinc stearate, magnesium stearate, calcium stearate and the like. Is preferably used.

In the present invention, an outer semiconductive layer composition containing polypropylene, thermoplastic polyolefin (TPO) and ethylene butyl acrylate (EBA) as a base resin is prepared and then extruded to prepare a specimen which can be used as an outer semiconductive layer for power distribution cable And the physical properties thereof were evaluated. As a result, it was confirmed that the physical properties such as tensile strength, elongation, heat resistance, volume specific resistance and peel strength were all excellent.

Accordingly, the present invention relates to an outer semiconductive layer composition for distribution grade cables characterized by containing polypropylene, thermoplastic polyolefin (TPO) and ethylene butyl acrylate (EBA) as a base resin from a different viewpoint.

In the present invention, the polypropylene may be any of random polypropylene, homopolypropylene, block polypropylene and the like as long as it can withstand the maximum allowable temperature of 110 to 120 ° C of the conductor as described above.

In the present invention, the thermoplastic polyolefin (TPO) is the same as that described above, and the ethylene butyl acrylate (EBA) is used for imparting the peel strength to the base resin.

The base resin may include 20 to 30 wt% of polypropylene, 5 to 15 wt% of thermoplastic polyolefin (TPO), and 60 to 70 wt% of ethylene butyl acrylate (EBA).

If the upper limit value of the polypropylene or the lower limit value of the ethylene butyl acrylate (EBA) is less than the upper limit value of the ethylene butyl acrylate (EBA) or the lower limit value of the polypropylene , There is a problem that physical properties at room temperature are deteriorated. In addition, when the thermoplastic polyolefin (TPO) is included in the above range, the tensile strength can be improved.

The outer semiconductive layer composition for power distribution cable of the present invention may further comprise a conductive material, an antioxidant, a processing aid and a dispersant.

The kind and content of the conductive material, the antioxidant and the processing aid are the same as those described above.

The dispersant is deagglomerated through steric stabilization of the conductive material and an electric charge is applied to the conductive material to generate an electric repulsive force between the conductive materials to prevent re-agglomeration, whereby a uniform dispersion of the conductive material in the base resin As shown in FIG. The dispersant may be appropriately selected from among dispersants conventionally used in a semiconductive composition for forming a semiconductive layer of a power cable, and examples thereof include ester or amide surfactants, silicone, and the like, but are not limited thereto . The dispersant may be used in an amount of 3 to 7 parts by weight based on 100 parts by weight of the base resin. If the content of the dispersant is less than 3 parts by weight, the dispersing effect is insignificant. If the content of the dispersant is more than 7 parts by weight, an excessive amount of ionic impurities may be caused.

Since the inner semiconductive layer composition for power distribution cable according to the present invention contains polypropylene and thermoplastic polyolefin (TPO) as a base resin, it is not necessary to undergo a separate crosslinking step and thus manufacturing cost can be reduced and crosslinked polyethylene XLPE), and it is possible to manufacture a power cable satisfying the physical characteristics and electrical characteristics required for the power cable.

Accordingly, in another aspect of the present invention, there is provided a semiconductor device comprising a conductor, an inner semiconductive layer surrounding the conductor, an insulation layer surrounding the inner semiconductive layer, an outer semiconductive layer surrounding the insulation layer, and a sheath layer surrounding the outer semiconductive layer Wherein the inner semiconductive layer is formed from an inner semiconductive layer composition comprising polypropylene and a thermoplastic polyolefin (TPO) as a base resin, the outer semiconductive layer comprising at least one of polypropylene, a thermoplastic polyolefin (TPO), and ethylene butyl acrylate EBA) as a base resin. The present invention relates to an eco-friendly power distribution cable.

The inner semiconductive layer composition and the outer semiconductive layer composition are the same as those described above.

[Example]

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for illustrating the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

[Examples 1 to 3] Preparation of inner semiconductive layer composition

As shown in Table 1, the polypropylene (LyondellBasell, CA 7441A) and thermoplastic polyolefins (LyondellBasell, Adflex ^® Q100F) one relative to the base resin of 100 parts by weight of carbon as a conductive material ^{(Orion Engineered Carbons, Hiblack ® 150B} ) mixed oxide, phenolic inhibitor (Songwon industrial Co. a / O1076) and PE wax (Honeywell, AC ^® 316A) for mixing and, 3ℓ / kneading apparatus for batch [DISPERSION kNEADER, Fine machinery industry Co., Ltd., Republic of Korea] in 20 minutes kneading at a temperature of 150 ℃ To prepare an inner semiconductive layer composition.

Thereafter, the inner semiconductive layer composition was injected into an extruder (EXTRUDER, Fine Machinery Industry Co., Ltd., Korea) having a diameter of 50 mm. The hopper was melted and kneaded at a temperature of 150 ° C, a temperature of the cylinder 1 of 165 ° C, a temperature of the cylinder 2 of 170 ° C and a die of 175 ° C, and extruded using a T-die (T-DIE) The test specimens were evaluated in the same manner as the inner semiconductive layer for distribution grade cables.

Furtherance Example 1 Example 2 Example 3 Base resin Polypropylene 90 80 90 Thermoplastic polyolefin (TPO) 10 20 10 Conductive material Carbon 60 60 50 Antioxidant Phenolic 0.5 0.5 0.5 Processing aid PE wax One One One

The prepared specimens were evaluated for properties such as tensile strength, elongation, heat resistance, volume resistivity and peel strength, and the results are shown in Table 2.

Methods and standards for measuring physical properties are as follows.

(1) Tensile strength and elongation: The tensile strength and elongation were measured in accordance with IEC 60811-1-1, and the tensile strength was 1.0kgf / ㎟ (inside), 0.8kgf / ㎟ (outside) box

(2) Heat resistance (tensile strength and elongation after heating): The tensile strength and elongation shall be measured in accordance with IEC 60811-1-1, and the elongation shall exceed 100%

(3) Volumetric specific resistance: measured according to ASTM D257, and should satisfy 5 × 10 ³ (20 ° C) and 5 × 10 ⁴ Ω · CM or less (90 ° C and 110 ° C)

(4) Peel strength: measured according to ICEA S-66-524, should be within the range of 0.82 ~ 4.07kgf

(5) Ion impurity: inner semiconductive layer: 300 ppm or less, outer semiconductive layer: 1500 ppm or less; The ionic impurities are 10 kinds of Ca, Si, Fe, Al, Zn, Cu, Mg, Na,

division Example 1 Example 2 Example 3 Remarks Tensile strength (kgf / mm ² ) 1.18 1.32 1.27 Elongation (%) 458 388 497 Tensile strength after heating (kgf / mm ² ) 1.31 1.29 1.29 136 占 폚 占 168 hours Elongation after heating (%) 341 324 387 136 占 폚 占 168 hours Volume resistivity
(Ω · CM) 20 ℃ 2.3 × 10 ¹ 2.5 × 10 ¹ 7.4 ² 90 ° C 3.4 x 10 ² 3.2 x 10 ² 8.1 x 10 ³ 110 ° C 4.6 × 10 ² 5.2 × 10 ² 2.4 × 10 ⁴ Ion impurity (ppm) 125 117 117

From Table 2, it can be seen that Examples 1 to 3 satisfy all physical properties such as tensile strength, elongation, heat resistance (tensile strength after heating, elongation) and volume resistivity.

[Comparative Examples 1 to 5] Preparation of inner semiconductive layer composition

As shown in Table 3, polypropylene (LyondellBasell, CA 7441A), thermoplastic polyolefins (LyondellBasell, Adflex ^® Q100F) or H-PP (LG Chem, H1500) for, based on 100 parts by weight of a mixture of the base resin, carbon (Orion Engineered of a conductive material Carbons, Hiblack ^® 150B), phenolic antioxidants (Songwon industrial Co. a / O1076) and PE wax (Honeywell, mixing the AC ^® 316A), and the kneading apparatus of 3ℓ / batch [DISPERSION kNEADER, Fine machinery industry Co., Ltd., Republic of Korea ] At 150 캜 for 20 minutes to prepare an inner semiconductive layer composition. Thereafter, the prepared inner semiconductive layer composition was tested in the same manner as in Example 1 to obtain a sample which can be evaluated in the same manner as the inner semiconductive layer for distribution grade cable.

Furtherance Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Base resin Polypropylene 90 90 100 90 70 Thermoplastic polyolefin (TPO) 10 10 0 0 30 H-PP 0 0 0 10 0 Conductive material Carbon 70 40 50 60 60 Antioxidant Phenolic 0.5 0.5 0.5 0.5 0.5 Processing aid PE wax One One One One One

The prepared specimens were evaluated for properties such as tensile strength, elongation, heat resistance, volume resistivity and peel strength, and the results are shown in Table 4.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Remarks Tensile strength (kgf / mm ² ) 1.04 1.24 0.88 1.26 1.36 Elongation (%) 388 511 437 445 387 Tensile strength after heating (kgf / mm ² ) 1.07 1.19 0.71 1.32 1.24 136 占 폚 占 168 hours Elongation after heating (%) 267 422 267 345 298 136 占 폚 占 168 hours Volume resistivity
(Ω · CM) 20 ℃ 2.3 × 10 ¹ 5.8 x 10 ⁴ 6.7 × 10 ¹ 2.4 × 10 ¹ 2.7 × 10 ¹ 90 ° C 6.7 × 10 ¹ 7.7 × 10 ⁵ 5.1 x 10 ² 3.9 × 10 ² 4.1 x 10 ² 110 ° C 3.4 x 10 ² 4.9 × 10 ⁶ 8.9 × 10 ² 6.8 × 10 ² 6.1 × 10 ² Ion impurity (ppm) 119 122 148 186 164

As can be seen from Table 4, in Comparative Example 1 using excess carbon, generally, all of the physical property standards are met. However, as shown in FIG. 2, the problem of surface protrusions occurs due to poor dispersibility at the time of extrusion. If projections are formed on the surface, insulation breakdown will occur, which will lead to cable performance degradation. On the other hand, in the case of Comparative Example 2 using carbon less than the proper amount, it was found that the desired performance level could not be maintained at the volume resistivity value.

In Comparative Example 3 using only polypropylene (PP) without using a thermoplastic polyolefin (TPO), the tensile strength standard at room temperature was not satisfied, and in Comparative Example 4 using H-PP instead of TPO, However, after the cable is compressed, there is a problem that the shrinkage occurs during the cooling process and the outside diameter can not be maintained.

In the case of Comparative Example 5 using a thermoplastic polyolefin (TPO) in an amount more than the proper amount, all the reference properties can be satisfied as in Comparative Example 4, but there is a problem in that the shrinkage occurs during the cooling process after the compression of the cable.

[Examples 4 to 5] Preparation of outer semiconductive layer composition

As shown in Table 5. Polypropylene (LyondellBasell, CA 7441A), and ethylene butyl acrylate (EBA) (Lucobit, 1400HN) or a thermoplastic polyolefin (LyondellBasell, Adflex ^® Q100F) and carbon, the conductive material with respect to a mixture of the base resin of 100 parts by weight ^{(Orion Engineered Carbons, Hiblack ® 150B} ), phenolic antioxidants (Songwon industrial Co. a / O1076), PE wax (Honeywell, AC ^® 316A) and a dispersant (BYK, BYK-P4101, silicon dioxide) mixed and, 3ℓ / batch to Kneaded at a temperature of 150 DEG C for 20 minutes in a kneading apparatus (DISPERSION KNEADER, Fine Machinery Co., Ltd., Korea) to prepare an external semiconductive layer composition.

Thereafter, the inner semiconductive layer composition was injected into an extruder (EXTRUDER, Fine Machinery Industry Co., Ltd., Korea) having a diameter of 50 mm. The hopper was melted and kneaded at a temperature of 150 ° C, a temperature of the cylinder 1 of 165 ° C, a temperature of the cylinder 2 of 170 ° C and a die of 175 ° C, and extruded using a T-die (T-DIE) The test specimens were evaluated in the same manner as the outer semiconductive layer for distribution grade cables.

Furtherance Example 4 Example 5 Base resin Polypropylene 20 30 Ethylene butyl acrylate (EBA) 70 60 Thermoplastic polyolefin
(TPO) 10 10 Conductive material Carbon 57 57 Antioxidant Phenolic 0.5 0.5 Processing aid PE wax One One Dispersant 실리콘 이산화물 5 5

The prepared specimens were evaluated for properties such as tensile strength, elongation, heat resistance, volume resistivity and peel strength, and the results are shown in Table 6.

division Example 4 Example 5 Remarks Tensile strength (kgf / mm ² ) 1.14 1.01 Elongation (%) 187 191 Tensile strength after heating (kgf / mm ² ) 1.05 0.89 121 占 폚 占 168 hours Elongation after heating (%) 155 158 121 占 폚 占 168 hours Volume resistivity
(Ω · CM) 20 ℃ 0.5 × 10 ¹ 1.5 × 10 ¹ 90 ° C 1.3 x 10 ² 2.4 × 10 ² 110 ° C 1.6 x 10 ² 4.8 × 10 ² Peel strength (kgf) 2.62 3.89 Ion impurity (ppm) 140 156

From Table 6, it can be seen that Examples 4 and 5 satisfy all physical properties such as tensile strength, elongation, heat resistance (tensile strength after heating, elongation), volume resistivity and peel strength.

[Comparative Examples 6 to 11] Preparation of external semiconductive layer composition

As shown in Table 7 Polypropylene (LyondellBasell, CA 7441A), and ethylene butyl acrylate (EBA) (lucobit, 1400hn) , EVA ( Hanwha total, e220f), or a thermoplastic polyolefin (LyondellBasell, Adflex ^® Q100F) a base resin 100 mixed with respect to the parts by weight of carbon as a conductive material (Orion Engineered Carbons, Hiblack ^® 150B), phenolic antioxidants (Songwon industrial Co. a / O1076), PE wax (Honeywell, AC ^® 316A) and a dispersant (BYK, BYK-P4101, silicon and the mixture was kneaded at 150 ° C for 20 minutes in a 3 l / batch kneader (DISPERSION KNEADER, Fine Machinery Co., Ltd., Korea) to prepare an external semiconductive layer composition. Thereafter, the prepared outer semiconductive layer composition was prepared in the same manner as in Example 1, and a specimen which can be evaluated in the same manner as the outer semiconductive layer for the distribution grade cable was prepared.

Furtherance Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Comparative Example 11 Base resin Polypropylene 20 50 30 30 30 10 Ethylene butyl acrylate (EBA) 80 50 70 70 0 70 EVA 0 0 0 0 70 0 Thermoplastic polyolefin (TPO) 0 0 0 0 0 20 Conductive material Carbon 57 57 40 70 57 57 Antioxidant Phenolic 0.5 0.5 0.5 0.5 0.5 0.5 Processing aid PE wax One One One One One One Dispersant 실리콘 이산화물 5 5 5 5 5 5

The prepared specimens were evaluated for properties such as tensile strength, elongation, heat resistance, volume resistivity and peel strength, and the results are shown in Table 8.

division Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Comparative Example 11 Remarks Tensile strength (kgf / mm ² ) 0.78 1.32 1.28 0.94 0.84 1.24 Elongation (%) 142 203 233 135 128 189 Tensile strength after heating (kgf / mm ² ) 0.67 1.18 1.09 0.82 0.68 1.09 121 占 폚 占 168 hours Elongation after heating (%) 122 175 184 98 87 147 121 占 폚 占 168 hours Volume resistivity
(Ω · CM) 20 ℃ 1.1 × 10 ¹ 1.7 × 10 ¹ 3.4 x 10 ² 1.5 × 10 ¹ 2.8 × 10 ¹ 0.5 × 10 ¹ 90 ° C 2.2 x 10 ² 1.8 x 10 ² 6.7 x 10 ⁴ 2.1 x 10 ² 2.6 x 10 ² 1.3 x 10 ² 110 ° C 3.6 x 10 ² 3.8 × 10 ² 3.5 × 10 ⁶ 3.7 x 10 ² 5.6 × 10 ² 1.6 x 10 ² Peel strength (kgf) 1.98 4.69 3.17 3.23 3.11 5.11 Ion impurity (ppm) 114 116 156 146 145 140

As can be seen from Table 8, in Comparative Example 6 using ethylene butyl acrylate (EBA) in an amount more than the proper amount, although the peel strength was excellent, ethylene butyl acrylate (EBA) whose room temperature properties (tensile strength and elongation) In Comparative Example 7, it was found that the peel strength did not satisfy the criterion.

Also, in the case of Comparative Example 8 using less than the proper amount of carbon, the desired level of performance can not be maintained at the volume resistivity value, and in Comparative Example 9 using carbon more than the proper amount, There arises a problem that surface protrusions are generated due to poor dispersibility at the time of extrusion. If projections are formed on the surface, insulation breakdown will occur, which will lead to cable performance degradation.

In Comparative Example 10 using ethylene vinyl acetate (EVA) instead of ethylene butyl acrylate (EBA), it has a relatively low room temperature property and can not be applied to cables after elongation after heating.

Finally, in Comparative Example 11 in which the content of polypropylene was low and the thermoplastic polyolefin was excessively added, it was found that the peel strength did not satisfy the criterion.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereto will be. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (15)

delete delete delete delete A base resin containing 20 to 30% by weight of polypropylene, 5 to 15% by weight of an ethylene-propylene copolymer and 60 to 70% by weight of ethylene butyl acrylate (EBA);
50 to 60 parts by weight of a conductive material with respect to 100 parts by weight of the base resin; 0.1 to 1 part by weight of an antioxidant; 0.1 to 2 parts by weight of a processing aid and 3 to 7 parts by weight of a dispersant.
delete delete delete A power cable comprising a conductor, an inner semiconductive layer surrounding the conductor, an insulation layer surrounding the inner semiconductive layer, an outer semiconductive layer surrounding the insulation layer, and a sheath layer surrounding the outer semiconductive layer,
Wherein the inner semiconductive layer comprises a base resin containing 80 to 90% by weight of a polypropylene and 10 to 20% by weight of an ethylene-propylene copolymer; 50 to 60 parts by weight of a conductive material with respect to 100 parts by weight of the base resin; 0.1 to 1 part by weight of an antioxidant and 0.1 to 2 parts by weight of a processing aid,
Wherein the outer semiconductive layer comprises a base resin containing from 20 to 30% by weight of polypropylene, from 5 to 15% by weight of an ethylene-propylene copolymer and from 60 to 70% by weight of ethylene butyl acrylate (EBA); 50 to 60 parts by weight of a conductive material with respect to 100 parts by weight of the base resin; 0.1 to 1 part by weight of an antioxidant; 0.1 to 2 parts by weight of a processing aid and 3 to 7 parts by weight of a dispersing agent. delete delete delete delete delete delete

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