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WO2009145436A1 - Câble supportant des températures élevées de réticulation par l'eau et une aptitude élevée au dénudage - Google Patents

Câble supportant des températures élevées de réticulation par l'eau et une aptitude élevée au dénudage Download PDF

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Publication number
WO2009145436A1
WO2009145436A1 PCT/KR2009/001607 KR2009001607W WO2009145436A1 WO 2009145436 A1 WO2009145436 A1 WO 2009145436A1 KR 2009001607 W KR2009001607 W KR 2009001607W WO 2009145436 A1 WO2009145436 A1 WO 2009145436A1
Authority
WO
WIPO (PCT)
Prior art keywords
semiconductive layer
weight
ethylene
vinyl acetate
melting point
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/KR2009/001607
Other languages
English (en)
Inventor
Ung Kim
Yong-Sun Lee
Do-Hyun Park
Jin-Ho Nam
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LS Cable and Systems Ltd
Original Assignee
LS Cable Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LS Cable Ltd filed Critical LS Cable Ltd
Publication of WO2009145436A1 publication Critical patent/WO2009145436A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/28—Protection against damage caused by moisture, corrosion, chemical attack or weather
    • H01B7/282—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable
    • H01B7/285—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable by completely or partially filling interstices in the cable
    • H01B7/288—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable by completely or partially filling interstices in the cable using hygroscopic material or material swelling in the presence of liquid
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
    • H01B3/44—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins
    • H01B3/441—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins from alkenes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
    • H01B3/44—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins
    • H01B3/448—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins from other vinyl compounds

Definitions

  • the present invention relates to a high voltage cable manufactured through a moisture-crosslinking process.
  • the present invention relates to a semiconductive layer composition that can improve crosslinking reaction temperature and strippability in a cable with a polyolefin insulating layer and an ethylene-vinyl acetate outer semiconductive layer.
  • a typical high voltage cable has a polyolefin (in particular, polyethylene) insulating layer 40 and an ethylene-vinyl acetate semiconductive layer 30 outside of the insulating layer 40.
  • the insulating layer 40 is moisture-crosslinked using unsaturated organic silane such as vinyl alkoxysilane.
  • the typical high voltage cable also has a conductor 60 and the other parts. A moisture-crosslinking process improves the properties of a polymer resin layer to provide suitable electrical and mechanical characteristics for a cable.
  • the high voltage cable is generally manufactured by an extruding process, and has a close adhesion between the insulating layer 40 and the outer semiconductive layer 30 to prevent a corona discharge.
  • a functional group for example, a silanol functional group may be added to the outer semiconductive layer 30 so as to assist adhesion of the outer semiconductive layer 30 to the insulating layer 40.
  • a moisture-crosslinking process is a function of temperature and time, and the higher the temperature of water used in crosslinking, the shorter the crosslinking time required. Accordingly, as crosslinking reaction proceeds at high temperature, productivity improves. However, crosslinking temperature is limited by a melting point of an ethylene-vinyl acetate resin of the outer semiconductive layer 30. If the crosslinking reaction proceeds at higher temperature than the melting point of the resin, agglutination and compression occurs to a wound cable.
  • the melting point of the ethylene-vinyl acetate resin can be increased by reducing the content of an ethylene-vinyl acetate copolymer, in a broader sense, vinyl acetate (acetate ester) monomer according to general characteristics of acetate ester copolymers of ethylene.
  • the outer semiconductive layer 30 is made from a lower content of vinyl acetate, the outer semiconductive layer 30 has lower polarity, and consequently stronger compatibility and attractive force with the insulating layer 40. As a result, it is difficult to strip the outer semiconductive layer 30 from the insulating layer 40 at an end of a cable, and thus cable installation workability is deteriorated. And, as mentioned above, addition of the silanol functional group improves adhesion between the outer semiconductor layer 30 and the insulating layer 40, but reduces strippability.
  • the present invention provides a semiconductive layer resin composition for a cable.
  • the semiconductive layer resin composition according to the present invention comprises a base resin consisting of 50 to 80 wt% of ethylene vinyl acetate copolymer and 20 to 50 wt% of high melting point polyolefin, said copolymer having been polymerized from a vinyl acetate monomer content of 30 to 70% by weight; and 20 to 80 parts by weight of carbon black based on 100 parts by weight of the base resin.
  • the high melting point polyolefin is at least one selected from the group consisting of ethylene-propylene copolymer, polypropylene and high density polyethylene, said ethylene-propylene copolymer having been polymerized from an ethylene monomer content of 5 to 20% by weight.
  • the ethylene-vinyl acetate copolymer has preferably a melt index of 0.1 to 20 g/10 min, and the high melting point polyolefin has preferably a melting point of 125°C or above and a melt index of 0.1 to 20 g/10 min.
  • the present invention also provides a cable including an inner semiconductive layer and/or an outer semiconductive layer made from the inventive resin composition, a conductor, a moisture-crosslinked polyolefin insulating layer, a sheath, and optionally a copper tape or neutral line as an electromagnetic shield.
  • moisture-crosslinking temperature can be increased up to 90°C and the crosslinking time can be reduced by 45% compared to conventional arts.
  • FIG. 1 is a cross-sectional view of a cable with an outer semiconductive layer made from a composition according to the present invention.
  • the resin composition according to the present invention includes a base resin of a ethylene-vinyl acetate (EVA) copolymer-based polymer blend, and carbon black.
  • the base resin includes 50 to 80 wt% of EVA copolymer. More specifically, the EVA copolymer is one polymerized with a content of 30 to 70% by weight for the vinyl acetate monomer in the reaction mixture.
  • the content for acetate, a polar functional group, within the base resin should be adequately controlled to ensure strippability and high temperature crosslinking stability of the inventive semiconductive layer composition. If the content of the EVA copolymer is less than 50 wt% in the base resin, strippability is reduced, and when heated, elongation is reduced below the standard. If the content of the EVA copolymer is more than 80 wt%, high temperature crosslinking stability is not obtained. Accordingly, a converted weight ratio of 15 to 56% by weight of the base resin for the vinyl acetate monomer is appropriate.
  • the EVA copolymer has a melt index (MI) of 0.1 to 20 g/10 min.
  • MI melt index
  • the melt index of the EVA copolymer is in the above-mentioned range, proper molecular weight and processing characteristics are obtained, leading to a polymer resin with suitable properties for a secmidoncutive material of a high voltage cable including mechanical strength. It also results in good processability in the manufacture.
  • the semiconductive layer resin composition according to the present invention includes 20 to 50 wt% of high melting point polyolefin in the base resin.
  • the high melting point polyolefin improves thermal deformation stability and increases crosslinking temperature.
  • the high melting point polyolefin of the present invention has a melting point of 125°C or above.
  • the melting point of the high melting point polyolefin is 125°C or above, advantageously thermal deformation of a cable is minimized during a crosslinking process. Because an ordinary person skilled in the art can properly set the maximum limit of the melting point of the high melting point polyolefin in consideration of desired final properties of the semiconductive layer, processing characteristics in the manufacture, prices and so on, the maximum limit is not described herein.
  • the high melting point polyolefin of the present invention is at least one selected from the group consisting of ethylene-propylene copolymer, polypropylene and high density polyethylene, the ethylene-propylene copolymer having been polymerized from an ethylene monomer content of 5 to 20% by weight. If the content of the high melting point polyolefin is less than 20 wt% in the base resin, thermal deformation increases during a high temperature crosslinking process. If the content of the high melting point polyolefin is more than 50 wt%, compatibility with an insulating layer becomes excessive, resulting in deterioration of strippability.
  • the high melting point polyolefin has a melt index of 0.1 to 20 g/10 min.
  • melt index of the high melting point polyolefin is in the above-mentioned range, proper molecular weight and processing characteristics are obtained, leading to a polymer resin with suitable properties for the secmidoncutive material of a high voltage cable including mechanical strength. It also results in good processability in the manufacture.
  • the semiconductive layer resin composition according to the present invention also includes 20 to 80 parts by weight of carbon black based on 100 parts by weight of the base resin. If the content of the carbon black is included less than 20 parts by weight in the resin composition, conductivity sufficient for a semiconductive material is not obtained. If the content of the carbon black is included more than 80 parts by weight, compatibility with an insulating layer becomes excessive, resulting in deterioration of strippability.
  • the semiconductive layer resin composition according to the present invention may further include an additive typically used in the art, for example, an antioxidant, a stabilizer, a lubricant or a processing aid.
  • an additive typically used in the art for example, an antioxidant, a stabilizer, a lubricant or a processing aid.
  • the present invention provides a cable including an inner semiconductive layer and/or an outer semiconductive layer made from the above-mentioned semiconductive layer resin composition.
  • the cable includes a conductor 60, an inner semiconductive layer 50 surrounding the conductor 60, an insulating layer 40 surrounding the inner semiconductive layer 50, an outer semiconductive layer 30 surrounding the insulating layer 40, and a sheath 10 surrounding the outer semiconductive layer 30.
  • the cable may include any one of a copper tape 20 and a neutral line 20 interposed between the sheath 10 and the outer semiconductive layer 30 to shield an electromagnetic wave, or none of the copper tape and the neutral line.
  • An outer semiconductive layer resin composition for a performance test was prepared according to examples and comparative examples as shown in Table 1.
  • ethylene-vinyl acetate (EVA) copolymer (MI 2.5) polymerized from a vinyl acetate monomer content of 46 weight% was used to prepare the base resin.
  • EVA ethylene-vinyl acetate
  • MI 2.5 ethylene-propylene copolymer
  • HDPE high density polyethylene
  • Furnace black was used as carbon black, 1.5 parts by weight of Tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane as an antioxidant, and 2 parts by weight of zinc stearate as a lubricant.
  • the prepared outer semiconductive layer compound was manufactured into a cable with a cross section shown in FIG. 1 by means of a single-screw extruder for manufacturing a cable.
  • a method for manufacturing a cable from a polymer compound using a single-screw extruder is well known to an ordinary person skilled in the art.
  • the cables manufactured according to examples and comparative examples were tested for mechanical characteristics of an outer semiconductive layer, strippability from an insulating layer, volume resistivity as a semiconductive material, and thermal deformation of a cable during a crosslinking process at 90°C for 14 hours.
  • the test results are shown in Table 2.
  • Each property standard is as follows.
  • volume resistivity when the cable sample is measured according to IEC 60502-2, the outer semiconductive material of the cable sample should have a volume resistivity of 100 ⁇ m or less.
  • the outer semiconductive layer resin composition according to the present invention has good properties including excellent strippability and high temperature crosslinking stability and mechanical characteristics meeting the standards at room temperature and after heating.
  • compositions according to the comparative examples included the same constituents for the polymer resin as the examples 1 and 2, but the composition ratio of the constituents were not in the range of the present invention.
  • the comparative examples did not meet the requirements for a cable.
  • the comparative example 1 included an insufficient amount of EVA copolymer, and consequently had strippability not in the standard range.
  • the comparative example 2 included an excessive amount of EVA copolymer and an insufficient amount of high melting point polyolefin, and consequently was not able to withhold a moisture-crosslinking temperature of 90°C.
  • the comparative examples 3 and 4 had the composition ratios of constituents for the base resin in the range of the present invention, but included carbon black out of the range of the present invention.
  • the comparative example 3 included an insufficient amount of carbon black, and consequently had higher volume resistivity than a normal volume resistivity as a semiconductive layer.
  • the comparative example 4 included an excessive amount of carbon black, and consequently had poor strippability, resulting in a cable of bad quality.
  • the outer semiconductive layer resin composition according to the present invention can support a high crosslinking process temperature of 90°C and has excellent strippability.
  • the resin composition was used as an outer semiconductive layer material
  • the semiconductive layer resin composition according to the present invention may be used as an inner semiconductive layer material.
  • the resin composition according to the present invention is very suitable for, in particular, an inner/outer semiconductive layer material of a cable of 6/10 kV and 22.9 kV.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Conductive Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

La présente invention porte sur une composition de résine de couche semi-conductrice pour un câble, qui présente une excellente aptitude au dénudage et une excellente stabilité dans des conditions de réticulation par l'humidité à température élevée. La composition de résine de couche semi-conductrice de la présente invention comprend une résine de base consistant en 50 à 80 % en poids d'un copolymère d'éthylène-acétate de vinyle et 20 à 50 % en poids d'une polyoléfine à point de fusion élevé, ledit copolymère ayant été polymérisé à partir d'une teneur en monomère acétate de vinyle de 30 à 70 % en poids ; et 20 à 80 parties en poids de noir de carbone sur la base de 100 parties en poids de la résine de base. De façon plus spécifique, la polyoléfine à point de fusion élevé est au moins une polyoléfine choisie dans le groupe constitué par un copolymère d'éthylène-propylène, le polypropylène et le polyéthylène haute densité, ledit copolymère d'éthylène-propylène ayant été polymérisé à partir d'une teneur en monomère éthylène de 5 à 20 % en poids.
PCT/KR2009/001607 2008-04-02 2009-03-30 Câble supportant des températures élevées de réticulation par l'eau et une aptitude élevée au dénudage Ceased WO2009145436A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR10-2008-0030959 2008-04-02
KR20080030959 2008-04-02

Publications (1)

Publication Number Publication Date
WO2009145436A1 true WO2009145436A1 (fr) 2009-12-03

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PCT/KR2009/001607 Ceased WO2009145436A1 (fr) 2008-04-02 2009-03-30 Câble supportant des températures élevées de réticulation par l'eau et une aptitude élevée au dénudage

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000315423A (ja) * 1999-04-28 2000-11-14 Fujikura Ltd 半導電性組成物及びこれを用いた直流用絶縁ケーブル
JP2001110235A (ja) * 1999-07-30 2001-04-20 Nippon Unicar Co Ltd 水架橋ポリエチレン絶縁電力ケーブルの外部半導電層用剥離性半導電性水架橋性樹脂組成物
US6284374B1 (en) * 1998-04-03 2001-09-04 Hitachi Cable Ltd. Strippable semiconductive resin composition and wire and cable

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6284374B1 (en) * 1998-04-03 2001-09-04 Hitachi Cable Ltd. Strippable semiconductive resin composition and wire and cable
JP2000315423A (ja) * 1999-04-28 2000-11-14 Fujikura Ltd 半導電性組成物及びこれを用いた直流用絶縁ケーブル
JP2001110235A (ja) * 1999-07-30 2001-04-20 Nippon Unicar Co Ltd 水架橋ポリエチレン絶縁電力ケーブルの外部半導電層用剥離性半導電性水架橋性樹脂組成物

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