KR102524353B1 - High-shielding light-weight cables including shielding layer of polymer-carbon composite - Google Patents

Abstract

The present invention relates to a cable for power transmission or communication, comprising: a core portion including one or more conductors and an insulating layer surrounding each conductor; a first shielding layer surrounding the core and formed of a polymer-carbon composite in which carbon-based particles are dispersed in a matrix of a polymer material and having an electrical resistance of 10 Ω·m or less; and a metal-based second shielding layer surrounding the first shielding layer. With this configuration, a lightweight cable with high shielding efficiency can be provided.

Description

High shielding and lightweight cable including a high-molecular-carbon composite shielding layer

The present invention relates to a high shielding and lightweight cable, and more particularly, to a cable having reduced weight and improved shielding efficiency by using a shielding layer made of a polymer-carbon composite containing carbon particles having high electrical conductivity.

A cable that transmits power or an electrical signal for communication, particularly a coaxial cable, includes various components for transmission performance and protection from the influence of the surrounding environment. In general, such a cable includes a solid or stranded conductor, an insulating layer made of a dielectric for electrical insulation, and a shielding layer made of a conductive material for shielding electromagnetic waves.

On the other hand, the size and length of the cable increase as the size of the equipment used increases. In particular, large-sized vehicles, ships, airplanes, railroads, spacecraft, etc. Kilometers of cable are used, and therefore, lightening the weight of the cable can greatly contribute to reducing the weight of the vehicle body and saving energy.

The conventionally used shielding layer is formed by winding a foil, weaving a tape, or braiding a wire, in which a metal material having high electrical conductivity occupies all or most of it. There has been a demand for a shielding layer of a new configuration and material to replace the phosphorus shielding layer.

To this end, a shielding layer formed of a metal foil such as copper or aluminum or a metal-polymer foil coated with a metal thin film on a polymer film has been proposed, but such a shielding layer is advantageous in reducing the weight of the cable, but has low shielding efficiency and does not cause significant electromagnetic interference. There was a disadvantage that it could be used only in a limited environment.

In addition, a copper braid with excellent shielding efficiency or a shielding layer using a combination of copper braid and metal foil (or metal-polymer foil) has been proposed, but the shielding efficiency of a cable including the copper braid increases as the coverage density of the copper braid increases. Therefore, for high shielding efficiency, the diameter or number of wires of the copper braid must be increased, and accordingly, the weight of the cable also increases.

On the other hand, attempts have been made to apply carbon nanostructures such as carbon fibers and carbon nanotubes, which are not metal but have excellent electrical conductivity and a much lighter mass, to cables. However, nanometer or micrometer-sized carbon structures should be applied to cables in the form of aggregates, but the electrical conductivity and shielding efficiency of the carbon material aggregates do not reach significantly compared to copper braids. In addition, in order to obtain shielding efficiency at the level of copper braid, an additional process such as doping or plating metal ions on carbon fiber is required, and this additional process takes a lot of time and money, so commercial application is greatly limited. In addition, in order to apply the carbon material aggregate to the cable as a shielding layer, there was a disadvantage that a new equipment and process other than the existing equipment or process were required.

Accordingly, the present invention solves the above problems, and it is possible to achieve high shielding efficiency while reducing the weight of the shielding layer by using a carbon material having excellent electrical conductivity and light weight, and using existing facilities without additional expensive processes. It is an object of the present invention to provide a highly shielded and lightweight cable that can be manufactured.

A cable for power transmission or communication of the present invention for achieving the above object includes a core portion including one or more conductors and an insulating layer surrounding each conductor; a first shielding layer surrounding the core and formed of a polymer-carbon composite in which carbon-based particles are dispersed in a matrix of a polymer material and having an electrical resistance of 10 Ω·m or less; and a metal-based second shielding layer surrounding the first shielding layer.

Here, the polymeric material may have a number average molecular weight of 1,000 g/mol or more, more preferably 10,000 g/mol or more, or more preferably 1,000,000 g/mol or more. can have

Such polymeric materials include, for example, epoxies, polyesters, vinylesters, polyetherimides, polyetherketoneketones, polyphthalamides, polyetherketones, polyetheretherketones, polyimides, phenolformaldehydes, bismaleimides, Polyethylene terephthalate, polycarbonate, acrylonitrile-butadiene styrene copolymer, or other thermoset materials may be used.

Also, the carbon-based particles may include particles having excellent electrical conductivity. These carbon-based particles include particles of graphite, graphene, graphene oxide, carbon nanotube (CNT), carbon fiber, and carbon black. or mixtures thereof. Preferably, the carbon-based particles may be in powder form. That is, the carbon-based particles may be composed of a single type of carbon material, or may be a mixture of two or more carbon materials having different structures and shapes, or may undergo additional processing to improve electrical conductivity or mixing with a polymer material. It may be made of a carbon material that has undergone.

The polymer-carbon composite may be produced through a process of mechanically mixing the polymer material and the carbon-based particles at a temperature equal to or higher than the processing temperature of the polymer material, wherein the processing temperature of the polymer material is equivalent to polymer degradation. It means a temperature enough to physically transform the shape of a polymer, such as mixing or extrusion, within the limit that does not occur. This processing temperature may be 40 °C or higher, preferably 60 °C or higher, more preferably 70 °C or higher. The electrical resistivity of the first shielding layer can be measured using a conventional low resistivity tester, and the electrical resistivity of the first shielding layer formed of a polymer-carbon composite is 10 Ω m at room temperature It may be less than or equal to, but more preferably 1 Ω·m or less. As such, the polymer-carbon composite according to the present invention has excellent electrical conductivity capable of providing high shielding efficiency.

In the present invention, the first shielding layer formed of a polymer-carbon composite may be formed by evenly applying the core portion through a commercially available melt extrusion process. Specifically, the first shielding layer may be formed by melting and extruding a polymer-carbon composite on the core portion along the length direction of the cable. This is one of the main advantages provided by the present invention. According to the present invention, the existing equipment used in the extrusion process of forming an insulation film or sheath during cable manufacturing can be used as it is in the process of forming a shielding layer of a polymer-carbon composite. In addition, the creation of the shielding layer on the cable manufacturing line can be designed as a continuous process.

In the case of a multi-core cable including a plurality of conductors in the core part, a filler may be further included to fill the space so that the plurality of conductors are united and the cross section is circular. In this case, the first shielding layer is a polymer on the filler. -Can be formed by melt-extruding a carbon composite.

In addition, a bedding layer that fixes the structure and shape of the core-filler or an inner sheath layer that protects the cable from external impact or corrosion may be added around the filler of the multi-core cable. In this case, the polymer on the bedding layer or the inner sheath layer - The first shielding layer may be formed by extruding the carbon composite.

However, the first shielding layer formed of the polymer-carbon composite may be extruded to function as a filler that fills the space between the cores and maintains the shape of the core. In this case, a separate filler may be omitted and the first shielding layer may be extruded. The first shielding layer functions as a filler in addition to the shielding function.

In addition, the first shielding layer formed of the polymer-carbon composite may be extruded around the filler to function as a bedding layer fixing the core-filler structure, so that the bedding layer may be omitted, and instead of the inner sheath layer, external shock or corrosion It may also exert a function of protecting the cable from the external sheath, and the inner sheath layer may be omitted if special conditions are not required for the cable in a special environment.

That is, the first shielding layer formed of the polymer-carbon composite according to the present invention can function as a filler, bedding layer, or inner sheath layer in addition to a high-efficiency shielding function, so that the filler, bedding layer, or inner sheath layer in the cable It is possible to reduce the weight of the cable by omitting the sheath layer or the like.

In the polymer-carbon composite, the content ratio of the polymer material to the carbon-based particles in the polymer-carbon composite may be determined such that the first shielding layer satisfies a set electrical resistance or the cable satisfies a set shielding efficiency.

For example, the content of the carbon-based particles is 5 parts by weight or more, more preferably 10 parts by weight or more, based on 100 parts by weight of the polymer material in order to secure excellent electrical conductivity of the first shielding layer and melt processability for an extrusion process. . Also, the content of the carbon-based particles may be 100 parts by weight or less, more preferably 50 parts by weight or less, based on 100 parts by weight of the polymer material.

The content of the carbon-based particles may be 5 parts by weight or more, more preferably 10 parts by weight or more, and 100 parts by weight or less, more preferably 50 parts by weight or less, based on 100 parts by weight of the polymer material.

In addition, the thickness of the first shielding layer may also be determined to satisfy a set electrical resistance or a set shielding efficiency.

For example, the first shielding layer may be formed to a thickness of 0.1 mm to 5 mm, more preferably 0.5 mm to 2 mm for excellent shielding efficiency and light weight of the cable. However, the thickness of the first shielding layer may be formed to exceed 5 mm if higher shielding efficiency is required even if the weight of the cable increases.

Meanwhile, the polymer-carbon composite may be crosslinked to improve mechanical and physical durability, heat resistance, oil resistance, etc. of the first shielding layer. For this purpose, the polymer-carbon composite may include a crosslinking agent and/or a crosslinking aid. (crosslinking co-agent) may be added. That is, a suitable crosslinking agent and crosslinking aid suitable for crosslinking conditions can be selected and mixed with a polymer material and carbon-based particles with a general mixer such as an internal mixer or a roll-mill mixer, After being applied on the core portion through the melt extrusion process described above, it may be crosslinked through a crosslinking process such as additional heating or irradiation with ultraviolet rays.

The second shielding layer may be formed by taping a metal foil or a metal-polymer foil, or by braiding several metal wires or wires. The type of metal constituting the second shielding layer is a metal having excellent electrical conductivity such as copper or aluminum.

In the case of forming the second shielding layer with a strip-shaped metal foil, the second shielding layer may be implemented through a helicoidal or longitudinal taping process. In addition, when the second shielding layer is formed with several strands of metal wire, the second shielding layer may be implemented through a braiding process. Surface density can be determined.

In a preferred embodiment, one or more third shielding layers formed of a polymer-carbon composite may be added radially inside or outside the second shielding layer. This third shielding layer can improve the overall shielding efficiency of the cable without increasing the second shielding layer made of metal.

The cable according to the present invention maintains excellent shielding efficiency by using a shielding layer formed of a polymer-carbon composite having very low electrical resistance or high electrical conductivity, and can significantly reduce weight compared to a cable having a shielding layer made of only conventional metal. There is an advantage to being Thus, when the cable according to the present invention is installed for power supply or communication of an electronic device such as a ship, vehicle, automobile, aircraft, etc., the weight of the vehicle body can be reduced and fuel efficiency can be increased.

In addition, the cable according to the present invention applies minute-sized particles of carbon material to the cable in the form of a polymer-carbon composite, and can be manufactured using an existing extruder, so it is easy to produce a production line without adding new equipment or processes. There are advantages that can be applied to In addition, the cable according to the present invention, by adjusting the composition ratio of the polymer-carbon composite, the thickness of the shielding layer and / or the number of shielding layers, can achieve the required shielding efficiency and light weight of the cable according to the purpose and environment of the cable installation It works.

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

Hereinafter, the present invention will be described in more detail through embodiments with reference to the accompanying drawings.

1 is a cross-sectional view of a cable according to an embodiment of the present invention. The illustrated cable 10 includes a core portion 100 , a first shielding layer 200 , a second shielding layer 300 and an outer sheath 400 . However, the components of the cable 10 of FIG. 1 are illustrative and not limited thereto, and may further include well-known cable configurations such as a soft skin layer, a semiconductive layer, an insulating layer, and a binder tape, and in some cases, some elements can be omitted.

The cable 10 shown in FIG. 1 is a multi-core cable including three multi-cores through which electromagnetic wave signals propagate. The core part 100 includes three cores 110, and each core 110 is a conductor. 111, an outer conductor layer 112 surrounding the conductor, and an insulating layer 113.

The conductor 111 is made of a metal having high electrical conductivity, such as copper, aluminum, aluminum alloy, or copper-clad aluminum. The conductor 111 may be a single solid conductor or a stranded conductor in which a plurality of thin wires are twisted together.

The outer conductor layer 112 surrounding the conductor 111 is a tape such as a separation tape, a fireproof tape, or a conductive tape that provides suitable functions depending on the purpose and use environment of the cable 10, and the conductor ( 111) can be formed on the outer surface. In addition, the outer conductor layer 112 is a semi-conductive layer formed on the outer surface of the conductor 111 through a melt extrusion process of a polymer composite containing a conductive component such as carbon black, and has a function of uniformly distributing the electric field of the twisted pair conductor and a conductor-insulator It can function to alleviate the concentration of partial discharge and local electrical stress at the interface. The outer conductor layer 112 is an optional component and may be omitted if necessary.

The insulating layer 113 surrounding the outer conductor layer 112 may be formed by melting and extruding a dielectric material on the outer surface of the outer conductor layer 112 . For example, when a fire resistant tape is overlapped on the conductor 111, the insulating layer 113 may be formed by melt-extruding a dielectric material along the longitudinal direction to uniformly wrap the fire resistant tape layer.

The above conductor 111, the outer conductor layer 112, and the insulating layer 113 constitute one core 110, and the three cores 110 form a core assembly twisted with each other at a constant pitch.

A filler 120 is disposed on the outer side of the core union unit to unite the cores and fill the cores to have a circular cross section. The filler 120 may be formed of polyester, polypropylene (PP), polyvinyl chloride (PVC), ethylene propylene diene monomer (EPDM), ester yarn, amide yarn, polyester yarn, aramid yarn, or the like. A material forming the filler 120 may be selected from various thermosetting or thermoplastic polymers having physical and chemical properties such as tensile strength, moisture resistance, and flame resistance, depending on the use of the cable 10 or the use environment. A bedding layer 130 is disposed around the filler 120 to maintain the core-filler configuration and shape, which may be made of PVC, PE, polyolefin, or the like.

As such, in this embodiment, one core part 100 is formed by including the filler 120 and the bedding layer 130 around the core assembly of the three cores 110 . However, the configuration of the core unit is not limited thereto, and may be composed of only a single core or a combination of two or four or more cores, and the filler 120 and the bedding layer 130 may be omitted depending on the usage environment of the cable. may be

According to the present invention, a first shielding layer 200 formed of a polymer-carbon composite is disposed around the core portion 100, and a metal-based second shielding layer 200 is disposed around the first shielding layer 200. A shielding layer 300 is disposed.

The polymer-carbon composite constituting the first shielding layer 200 is formed by mechanically mixing the polymer material and the carbon-based particles above the processing temperature of the polymer material. The polymeric material may have a number average molecular weight of 1,000 g/mol or more, preferably a number average molecular weight of 10,000 g/mol or more, or 1,000,000 g/mol or more. Such polymeric materials include, for example, epoxies, polyesters, vinylesters, polyetherimides, polyetherketoneketones, polyphthalamides, polyetherketones, polyetheretherketones, polyimides, phenolformaldehydes, bismaleimides, Polyethylene terephthalate, polycarbonate, acrylonitrile-butadiene styrene copolymer, or other thermoset materials may be used.

The carbon-based particles are formed of one or more powders of graphite, graphene, graphene oxide, carbon nanotubes, carbon fibers, and carbon black. That is, the carbon-based particles may be made of a single type of carbon material, or may be formed of a mixture of two or more carbon materials having different structures and shapes, or additionally treated to improve electrical conductivity or mixing with a polymer material. Processed carbon materials may also be used.

In particular, the first shielding layer 200 is formed to have an electrical resistivity of 10 Ω m or less, and this electrical resistivity can be measured through a low resistivity tester, and the first shielding layer By forming the polymer-carbon composite having excellent conductivity, the electrical resistivity can be formed to 10 Ω·m or less, more preferably 1 Ω·m or less. As such, the cable according to the present invention can be highly shielded and lightened by using a shielding layer formed of a polymer-carbon composite capable of reducing weight while providing high shielding efficiency.

The first shielding layer 200 is formed by extruding a polymer-carbon composite on the core part 100 along the longitudinal direction of the cable through a commercial melt extrusion process. That is, the polymer-carbon composite constituting the first shielding layer of the present invention can be disposed on the core part 100 using existing equipment used in cable manufacturing, and no new equipment or process is required.

In this embodiment, since the core part 100 includes the filler 120 and the bedding layer 130 around the core assembly, the first shielding layer 200 is formed by extruding the polymer-carbon composite on the bedding layer 130. is formed However, since the polymer-carbon composite itself can function as a filler that fills the core assembly so that the cross section is circular, and can also function as a bedding layer to maintain the core-filler configuration, in another embodiment, The bedding layer may be omitted, or both the filler and the bedding layer may be omitted, and the first shielding layer 200 formed of a polymer-carbon composite may replace them.

In addition, although not shown in this embodiment, an inner sheath layer protecting the cable from external impact or corrosion may be added around the core portion 100, but the polymer-carbon composite itself protects the cable. Therefore, in another embodiment, the first shielding layer formed of the polymer-carbon composite may replace the inner sheath layer to perform the function.

That is, the first shielding layer 200 formed of the polymer-carbon composite according to the present invention can function as a filler, bedding layer, or inner sheath layer in addition to a low-weight and high-efficiency shielding function, so that the filler in the cable, the bedding The cable can be further reduced in weight by omitting the layer or the inner sheath layer.

As described above, the polymer-carbon composite of the first shielding layer 200 has a content of carbon-based particles in 100 parts by weight of a polymer material in order to provide excellent electrical conductivity and secure melt processability for a commercial extrusion process. 5 parts by weight or more, more preferably 10 parts by weight or more, and 100 parts by weight or less, more preferably 50 parts by weight or less. In particular, the content ratio of the polymer material to the carbon-based particles in the polymer-carbon composite is determined so that the first shielding layer satisfies the set electrical resistance or the cable satisfies the set shielding efficiency.

In addition, the thickness of the first shielding layer 200 is also determined to satisfy a set electrical resistance or a set shielding efficiency, and is 0.1 mm to 5 mm, more preferably 0.5 mm for excellent shielding efficiency and light weight of a cable. mm to 2 mm in thickness. However, the thickness of the first shielding layer may be formed to exceed 5 mm if higher shielding efficiency is required even if the weight of the cable increases. At this time, the thickness of the first shielding layer is defined as the shortest distance between the upper layer and the lower layer in contact with the first shielding layer. Since it contacts the layer 300, the thickness of the first shielding layer is the shortest distance between the outer surface of the bedding layer 130 and the inner surface of the second shielding layer 300. In another embodiment, when the bedding layer 130 and the filler 120 of the core portion are omitted, the first shielding layer 200 comes into contact with the insulating layers 113 of the cores, so the thickness of the first shielding layer is This will be the shortest distance between the outer surface of the layer 113 and the inner surface of the second shielding layer 300 .

Meanwhile, the polymer-carbon composite may be crosslinked to improve mechanical and physical durability, heat resistance, oil resistance, etc. of the first shielding layer 200, and for this purpose, a crosslinking agent and/or a crosslinking aid may be added to the polymer-carbon composite. there is. The crosslinking agent and the crosslinking aid may be mixed with a general mixer such as an internal mixer or a roll-mill mixer, and after the polymer-carbon composite is applied on the core part through a melt extrusion process, crosslinking such as additional heating or irradiation with ultraviolet rays It can be cross-linked through the process.

The second shielding layer 300 may be formed by taping a metal foil or a metal-polymer foil, or by braiding several metal wires or wires. The type of metal constituting the second shielding layer 300 is a metal having excellent electrical conductivity such as copper or aluminum.

When the second shielding layer 300 is a metal foil in the form of a strip, it is implemented through an overlapping or terminating taping process, and when multiple strands of metal wire are used, it is implemented through a braiding process. In this case, the metal wire ( wire) is a copper wire, a tin-coated copper wire, an aluminum wire, an aluminum alloy wire, a copper coated aluminum wire, and a metal composite wire in which a metal such as copper, aluminum, or nickel is plated on a polymer or carbon fiber, and a metal The surface density of the braided shielding layer is determined so that the cable satisfies the set shielding efficiency.

In this embodiment, an outer sheath 400 formed of a material suitable for the purpose and use environment of the cable 10 is disposed around the second shielding layer 300 .

Although not shown, in another embodiment, one or more third shielding layers formed of a polymer-carbon composite may be added around the second shielding layer 300 like the first shielding layer, or the second shielding layer may be added as needed. One or more third shielding layers may also be added between the first shielding layer and the inner side of 300 . By adding such a third shielding layer, the overall shielding efficiency of the cable can be improved without increasing the thickness of the second shielding layer made of metal if necessary.

yes

The following is a test and comparison of the shielding efficiency and weight of the cable manufactured according to the present invention and the cable manufactured according to the conventional configuration.

In this example, the cable manufactured according to the present invention and the cable according to the conventional configuration have the same core portion as follows:

The copper stranded wire assembly forming the conductor was manufactured by winding 47 strands of tin-coated copper wire with a diameter of 0.255 ± 0.005 mm rightward at intervals of 99.0 mm pitch, in accordance with IEC 60228 (class 2). Two types of fireproof tapes with different widths were wound on the copper stranded wire assembly to form a conductor outer layer composed of two layers. A fireproof tape (mica-glass tape, SR854G, One IMC) with a width of 10 mm and a thickness of 0.130 mm is overlapped at an overlapping rate of 45 ± 5%, and a fireproof tape with a width of 15 mm and a thickness of 15 mm is applied on the fireproof tape. A 0.130 mm fire resistant tape was overlapped with an overlapping tolerance of 45±5%. The insulation layer of the copper twisted pair assembly taped with the fireproof tape is an insulation compound based on ethylene-propylene copolymer (E-80, Kukdong Electric Wire) in accordance with IEC 60092-351 (HF-HEPR). ) was melt-extruded to a thickness of 0.900 ± 0.100 mm on top of the fire resistant tape layer, and then crosslinked in a high temperature/high pressure CCV line (catenary continuous vulcanization line) to form. Fire-resistant tape was wound around the copper stranded wire assembly, and three cores coated with an insulating layer were prepared, and the three cores were rotated clockwise at intervals of 171.0 mm pitch and united. The filler was formed by combining three cores by placing three binder fillers (13500 denier, Sungwon Industry) with a width of 55 mm prepared by gathering amide fiber yarns in the form of a binder in the empty space between each core.

Meanwhile, in the cable manufactured according to the present invention, the polymer-carbon composite is a NBR-CNT composite formed by mixing nitrile rubber (NBR) as a base and carbon nanotubes (CNT) at 20 parts by weight relative to 100 parts by weight of NBR. (K-Nanos-INB141, Kumho Petrochemical) was used, and the electrical resistivity measured at room temperature with a low resistance meter was 1 Ω cm.

For crosslinking of the NBR-CNT composite, 1 part by weight of bis( t -butyl peroxyisopropyl) benzene (Perbutyl P, NOF Corporation), a hydrogen peroxide-based crosslinking agent, was added based on 100 weight of the NBR-CNT composite, and the mixture was mixed with a roll-mill mixer. It was mixed for 5 minutes at a roll temperature of 80°C.

The NBR-CNT composite to which the crosslinking agent was added was obtained in the form of a long ribbon to enable continuous injection, and it was extruded to a thickness of 1 mm on the core portion including the core-filler to form a first shielding layer, after the extrusion process It was crosslinked in a high temperature/high pressure catenary continuous vulcanization line (CCV line).

The second shielding layer around the first shielding layer was formed of a metal braid. In order to prevent damage to the NBR-CNT composite shielding layer, first, a PET tape having a thickness of 0.05 mm and a width of 50 mm was taped at the end, and the PET tape A metal braid is applied on the layer, and the metal braid is made by twisting a set of 16 copper wires consisting of N strands of tin-coated copper wires with a diameter of 0.300 mm into a piece of 36.17° with a pitch of 55 mm. formed by braiding. At this time, the cables of Examples 1 to 4 having different surface densities were prepared by forming copper wire sets with copper wires of 9 strands, 6 strands, 4 strands, and 2 strands where N was 9, 6, 4, and 2, respectively. It became.

The surface density of a copper braid can be obtained by the following formula specified in IEC 60092-350:2014:

Here, G is the surface density, F is the filling factor, α is the angle formed by the piece, that is, the cable axis and the copper wire, d is the diameter of the copper wire, and N is the carrier of the copper wire The number of strands of the copper wire constituting , P means the number of peaks per mm.

That is, the surface density of the copper braid of the cables of Examples 1 to 4 was 104% (Example 1, SC104), 69% (Example 2, SC69), 46% (Example 3, SC46) and 23% (Example 3, SC46), respectively. Example 4, SC23).

On the other hand, the cable of the comparative example (Control) manufactured according to the conventional configuration extrudes a conventional SHF2 type bedding layer (XLPO-5, Kukdong Electric Wire) around the filler of the core part, and after the extrusion process, high temperature / high pressure CCV It was crosslinked at the catenary continuous vulcanization line.

A metal braided shielding layer was formed around the bedding layer. As in Examples 1 to 4, in order to prevent damage to the bedding layer, first, a PET tape having a thickness of 0.05 mm and a width of 50 mm was taped at the end, and then, thereon, Metal braiding is applied, and the metal braiding is a copper braid made by twisting 16 sets of copper wires consisting of 9 strands of tin-coated copper wire with a diameter of 0.300 mm into a piece of 36.17° with a pitch of 55 mm. was formed Therefore, the surface density of the copper braid of the cable of the comparative example was 104%, the same as in Example 1.

For the cables of Examples 1 to 4 (SC104, SC69, SC46, SC23) and Comparative Example (Control), IEC 62153-4- 3: 2013 and IEC 62153-4-4: 2015 standard to measure the transfer impedance (transfer impedance) and screening attenuation (screening attenuation) to measure the shielding efficiency at a frequency ranging from 300 kHz to 1 GHz. In addition, the weight of the cable was determined by averaging the weight of 5 samples prepared by preparing each cable by 5 m and cutting it in units of 1 m.

The results of measuring the shielding efficiency and weight of the cables of Examples 1 to 4 and Comparative Examples are shown in Table 1 below:

cable Shielding efficiency (dB) according to frequency Weight (g/m)
Decrease rate (%) 300 kHz 3 MHz 30 MHz 300 MHz 1 GHz comparative example
Control 85 66 53 44 55 300
Example 1
SC104 85 67 55 56 57 280
(6.7%) Example 2
SC69 76 58 45 47 54 255
(15%) Example 3
SC46 71 52 38 41 52 235
(22%) Example 4
SC23 68 48 33 37 47 220
(27%)

As can be seen from Table 1, when the non-conductive SHF2 bedding layer of a conventional cable (comparative example) having a surface density of 104% of the same copper braided shielding layer is replaced with an NBR-CNT composite shielding layer (Example 1) , the shielding efficiency was improved in all frequency ranges, and in particular, at 300 MHz, it can be confirmed that it is improved by about 27% or more compared to the conventional cable (comparative example). This means that the cable (SC104) including the NBR-CNT composite shielding layer of Example 1 according to the present invention is a cable with high shielding performance that can be used even in an environment with severe electromagnetic interference (EMI). At the same time, the weight per unit meter of the cable (SC104) of Example 1 according to the present invention was reduced by about 6.7% compared to the conventional cable (Comparative Example). This is because the specific gravity of the NBR-CNT composite used in the cable according to the present invention is 1.12, which is lower than the specific gravity of the SHF2 bedding layer of the conventional cable, which is 1.20. Also, consider that the shielding efficiency required for general signal/control cables is 40dB or higher. At this time, the cable (SC69) of Example 2 in which the surface density of the copper braided shielding layer was lowered to 69% by using the NBR-CNT composite shielding layer according to the present invention also had a shielding efficiency of 40 dB or more in all measured frequency ranges, It can be confirmed that it can be sufficiently used as a lightweight cable.

In the cable of Example 3 (SC46) and the cable of Example 4 (SC23) according to the present invention, the surface density of the copper braided shielding layer was significantly lowered to 46% and 23% using the NBR-CNT composite shielding layer, so that the weight was reduced, respectively. It was reduced by 22% and 27%, and the shielding efficiency was less than 40dB in some frequency bands, but it can be used in some frequency domains where the shielding efficiency can be over 40dB or used as a lightweight cable in an environment where electromagnetic interference is not severe. You can check.

In addition, even if the surface density of the copper braided shielding layer is significantly lowered as in the cables of Examples 3 and 4 above, the filler in the core part is omitted and the NBR-CNT composite shielding layer is formed thicker, or the CNT composite in the NBR-CNT composite is formed. The shielding efficiency can be sufficiently increased to 40 dB or more by increasing the particle content or adding an NBR-CNT composite shield layer on top of the copper braid shield layer.

In the above, preferred embodiments of the present invention have been shown and described, but the present invention is not limited to the specific embodiments described above, and without departing from the configuration of the present invention claimed in the following claims, in the technical field to which the present invention belongs Various modifications are possible by those skilled in the art, and such modifications are within the scope of the claims.

10: cable 100: core part
110: core 111: conductor
112: outer conductor layer 113: insulating layer
120: filler 130: bedding layer
200: first shielding layer 300: second shielding layer
400: outer sheath

Claims (22)

As a cable for power transmission or communication,
a core portion including one or more conductors and an insulating layer surrounding each conductor;
It surrounds the core and is formed of a polymer-carbon composite in which carbon-based particles are dispersed in a matrix of a polymer material, and has an electrical resistance of 10 Ω m or less and a thickness of 0.5 mm to 2 mm A first shielding layer having a; and
A metal-based second shielding layer surrounding the first shielding layer; includes,
The polymer-carbon composite is cross-linked, the content of the carbon-based particles is 10 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the polymer material, and the polymer-carbon composite is formed at a processing temperature of the polymer material or higher. Characterized in that it is formed by mechanically mixing a material and the carbon-based particles. According to claim 1,
The polymeric material is characterized in that it has a number average molecular weight of 1,000 g / mol or more, cable. According to claim 1,
The carbon-based particles are characterized in that selected from graphite, graphene, graphene oxide, carbon nanotubes, carbon fibers, carbon black, and mixtures thereof, the cable. According to claim 1,
The first shielding layer is characterized in that formed by melting and extruding the polymer-carbon composite along the length direction of the cable on the core portion, the cable. According to claim 1,
The core part includes a plurality of conductors, and further includes a filler that unites the plurality of conductors and fills the space so that the cross section is circular,
The first shielding layer is characterized in that formed by melting and extruding the polymer-carbon composite on the filler, the cable. According to claim 1,
The polymer-carbon composite of the first shielding layer functions as a filler around the core part, a bedding layer, or an inner sheath layer. According to claim 1,
The second shielding layer is characterized in that formed by taping a metal foil or a metal-polymer foil, or by braiding several strands of metal wire. According to claim 1,
The second shielding layer is formed by braiding several strands of metal wires,
Characterized in that, the surface density of the metal braid is determined so that the cable satisfies the set shielding efficiency. According to claim 1,
Characterized in that it further comprises at least one third shielding layer formed of a polymer-carbon composite radially inside or outside the second shielding layer. According to claim 1,
Characterized in that the polymer-carbon composite is crosslinked by including a crosslinking agent and/or a crosslinking co-agent. According to claim 1,
The polymer material is epoxy, polyester, vinyl ester, polyetherimide, polyether ketone ketone, polyphthalamide, polyether ketone, polyether ether ketone, polyimide, phenol formaldehyde, bismaleimide, polyethylene terephthalate, poly A cable, characterized in that it is selected from the group consisting of carbonates and acrylonitrile-butadiene styrene copolymers. According to claim 2,
Characterized in that the polymer material has a number average molecular weight of 10,000 g / mol or more, cable. According to claim 12,
The polymeric material is characterized in that it has a number average molecular weight of 1,000,000 g / mol or more, cable. According to claim 1,
The cable, characterized in that the first shielding layer has an electrical resistance of 1 Ω m or less. According to claim 1,
Characterized in that the carbon-based particles are in powder form. According to claim 1,
Characterized in that the polymer-carbon composite is formed by mechanically mixing the polymer material and the carbon-based particles at a temperature of 40 ° C, 60 ° C or 70 ° C or higher. delete delete delete delete delete delete

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