KR102278263B1 - Power cable - Google Patents

Abstract

The present invention relates to a power cable. Specifically, the present invention relates to a power cable having a watertight layer that is lightweight compared to a conventional power cable, has excellent corrosion resistance, and maintains interlayer adhesion despite external physical impact and temperature change, thereby effectively suppressing peeling.

Description

power cable

The present invention relates to a power cable. Specifically, the present invention relates to a power cable having a watertight layer that is lightweight compared to a conventional power cable, has excellent corrosion resistance, and maintains interlayer adhesion despite external physical impact and temperature change, thereby effectively suppressing peeling.

Power cables, such as submarine cables and underground cables, generally include a watertight layer that suppresses penetration of moisture from the outside.

1 schematically shows a cross-sectional structure of a power cable disclosed in US Patent No. 4,472,597. As shown in Figure 1, the conventional power cable has a conductor (1), an inner semiconducting layer (2), an insulating layer (3), an outer semiconducting layer (4), a metal shielding layer (5), a conductive tape layer (8) , a watertight layer 7 , and an outer jacket 6 may have a structure including these components in the order.

Here, when an aluminum laminate tape coated with polyethylene on both sides of an aluminum foil is used as the watertight layer 7 , the aluminum foil is vulnerable to corrosion by moisture passing through the outer jacket 6 . Damage can shorten the life of the cable.

On the other hand, Figure 2 schematically shows the cross-sectional structure of the power cable disclosed in US Patent Publication No. 4,501,928. As shown in FIG. 2, the conventional power cable has a conductor 1', an inner semiconducting layer 2', an insulating layer 3', an outer semiconducting layer 4', a metal shielding layer 5', and a semiconducting layer. The conductive tape 6', the watertight layer 7', and the outer jacket 8' may have a structure including these components in the order.

Here, when a lead-laminated tape coated with polyethylene, polyvinyl chloride, etc. on both sides of a lead foil is used as the watertight layer 7', the lead foil is heavy in weight and the lightness of the cable may be reduced. can

In addition, the watertight layers 7 and 7' applied to the conventional power cables have insufficient adhesion with the outer jackets 6 and 8', so that the watertight layers 7 and 7' are caused by external physical impact and temperature change. and the outer jackets 6 and 8' are separated from each other.

Therefore, there is an urgent need for a power cable having a watertight layer that is lightweight compared to conventional power cables, has improved corrosion resistance, and maintains interlayer adhesion despite external physical shocks and temperature changes, thereby effectively suppressing peeling.

An object of the present invention is to provide a power cable that is lightweight compared to a conventional power cable.

In addition, an object of the present invention is to provide a power cable having a watertight layer in which corrosion resistance is improved and delamination is effectively suppressed by maintaining interlayer adhesion despite external physical impact and temperature change.

In order to solve the above problems, the present invention,

central conductor layer; an inner semiconducting layer surrounding the central conductor layer; an insulating layer surrounding the inner semiconducting layer; an outer semiconducting layer surrounding the insulating layer; a metal layer positioned outside the outer semiconducting layer and made of a plurality of metal wires; a watertight layer surrounding the outside of the metal layer; an adhesive layer surrounding the outside of the watertight layer; and a jacket layer surrounding the outside of the adhesive layer.

Here, a first semiconducting layer located between the outer semiconducting layer and the metal layer; a second semiconducting layer located between the metal layer and the watertight layer; And it provides a power cable, characterized in that it further comprises an auxiliary adhesive layer located between the watertight layer and the adhesive layer.

In addition, the thickness of the watertight layer is 0.1 to 0.25 mm, and the thickness of the auxiliary adhesive layer is 0.05 to 0.09 mm, it provides a power cable, characterized in that.

And, the adhesive forming the auxiliary adhesive layer provides a power cable, characterized in that it comprises a copolymer or blend resin of an olefin and a polar monomer.

Further, the polar monomer is a vinyl ester monomer of vinyl acetate or vinyl versatate, a vinyl-unsaturated carboxylic acid monomer of methacrylic acid, acrylic acid, maleic acid or itaconic acid, an acrylic monomer of (meth)acrylate or alkyl (meth)acrylate It provides a power cable, characterized in that.

On the other hand, the random copolymer resin of the olefin and the polar monomer provides a power cable, characterized in that ethylene acrylic acid (EAA), ethylene vinyl acetate (EVA) or ethylene butyl acrylate (EBA).

Here, the content of the polar monomer, based on the total weight of the random copolymer resin, it provides a power cable, characterized in that 5 to 20% by weight.

And, the watertight layer provides a power cable, characterized in that both ends overlap each other.

Here, in the overlapping region where both ends of the water-tight layer overlap, the lower surface and the upper surface of both ends of the water-tight layer are bonded by a hot melt adhesive, to provide a power cable.

In addition, the hot melt adhesive provides a power cable, characterized in that it has a creep resistance temperature and a softening temperature of 80 ℃ or more.

And, the hot melt adhesive provides a power cable, characterized in that it comprises a polyamide resin, a polyethylene vinyl acetate resin, or both.

On the other hand, the adhesive layer provides a power cable, characterized in that it comprises a resin having a density of 0.93 or more and a crystallinity of more than 50%.

Here, the adhesive layer provides a power cable, characterized in that it comprises a high-density polyethylene (HDPE) resin.

In addition, the adhesive layer provides a power cable, characterized in that it does not contain an additive capable of forming a moisture movement path.

And, it provides a power cable, characterized in that the thickness of the adhesive layer is 1 to 3 mm.

Furthermore, the jacket layer includes a high-density polyethylene (HDPE) resin, and provides a power cable, characterized in that the thickness is 5 to 7.5 mm.

On the other hand, the adhesive auxiliary layer is an adhesive having an adhesive strength such that the residual ratio of the peel force of the jacket layer with respect to the watertight layer measured after immersing the power cable in a basic aqueous solution of pH 8.5 and a temperature of 80° C. for 7 days is 70% or more. It provides a power cable, characterized in that it comprises.

And, it provides a power cable, characterized in that it further comprises a buffer layer for absorbing the external impact to the cable between the water-tight layer and the adhesive layer.

Meanwhile, a conductor layer, an inner semiconducting layer surrounding the conductor layer, an insulating layer surrounding the inner semiconducting layer, an outer semiconducting layer surrounding the insulating layer, and a metal layer surrounding the outside of the outer semiconducting layer In a method of manufacturing a power cable In the above, the watertight layer forming step of forming a watertight layer by attaching the overlapping portions of both ends of the metal tape to the ends of the metal tape formed on the upper surface of the auxiliary adhesive layer on the outside of the metal layer, and the adhesive on the outside of the auxiliary adhesive layer An adhesive layer forming step of extruding the adhesive layer at an extrusion temperature higher than or equal to the melting point of the auxiliary layer, and a jacket layer forming step of extruding the jacket layer at an extrusion temperature higher than or equal to the melting point of the adhesive layer to the outside of the adhesive layer.

Here, the method of manufacturing a power cable, characterized in that it further comprises a first semiconducting layer forming step of forming a first semiconducting layer surrounding the outer semiconducting layer with a first semiconducting tape before the watertight layer forming step provides

In addition, it provides a method of manufacturing a power cable, characterized in that it further comprises a second semiconducting layer forming step of forming a second semiconducting layer surrounding the metal layer with a second semiconducting tape before the watertight layer forming step do.

And, in the watertight layer forming step, the overlapping portion provides a method of manufacturing a power cable, characterized in that the bonding with a hot melt adhesive having a creep resistance temperature or softening point of 80 ℃ or more.

Furthermore, it provides a method of manufacturing a power cable, characterized in that the adhesive layer is formed by extrusion of a resin having a density of 0.93 or more and a crystallinity of more than 50% in the adhesive layer forming step.

The power cable according to the present invention exhibits an excellent effect of being lightweight compared to the conventional power cable by including a watertight layer made of a lightweight material.

The power cable according to the present invention exhibits an excellent effect of suppressing corrosion of the watertight layer by including a watertight layer made of a material having excellent corrosion resistance.

The power cable according to the present invention improves the adhesion between the watertight layer and the outer jacket and further includes an adhesive layer that can effectively suppress moisture penetration, which is the main cause of lowering the adhesion between the watertight layer and the outer jacket. And it effectively suppresses the peeling of the watertight layer even with a change in temperature, and consequently shows an excellent effect of maintaining the function of the watertight layer and suppressing the shortening of the life of the cable.

1 schematically shows a cross-sectional structure according to an embodiment of a conventional power cable.
2 schematically shows a cross-sectional structure of another embodiment of a conventional power cable.
3 is a cross-sectional view schematically showing a cross-sectional structure according to an embodiment of a power cable according to the present invention.
4 is a longitudinal cross-sectional view schematically showing a cross-sectional structure according to an embodiment of a power cable according to the present invention.
5 is a schematic enlarged view of the cross-sectional structure of the overlapping portion of the watertight layer in FIG. 4 .

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed subject matter may be thorough and complete, and that the spirit of the present invention may be sufficiently conveyed to those skilled in the art. Like reference numerals refer to like elements throughout.

3 and 4 schematically show a cross-sectional structure of an embodiment of a power cable according to the present invention. 3 and 4, the power cable according to the present invention has a central conductor layer 10, an inner semiconducting layer 20 surrounding the central conductor layer 10, and an insulation surrounding the inner semiconducting layer 20. Layer 30, an outer semiconducting layer 40 surrounding the insulating layer 30, a metal layer 50 formed of a plurality of metal wires located outside the outer semiconducting layer 40, and surrounding the outside of the metal layer 50 It may include a watertight layer 60 , an adhesive layer 70 surrounding the outside of the watertight layer 60 , and a jacket layer 80 surrounding the outside of the adhesive layer 70 .

In addition, the power cable according to the present invention includes a first semiconducting layer 45 located between the outer semiconducting layer 40 and the metal layer 50 , and a second located between the metal layer 50 and the watertight layer 60 . A semiconducting layer 55 , an auxiliary adhesive layer 65 positioned between the watertight layer 60 and the adhesive layer 70 , and the like may be further included.

The central conductor layer 10 may be made of a single wire made of copper, aluminum, preferably copper, or a stranded wire in which a plurality of conductive wires are combined, and the diameter of the central conductor layer 10 and the diameter of the strands constituting the stranded wire The standard including the etc. may be different depending on the transmission voltage, use, etc. of the power cable including the same, and may be appropriately selected by a person skilled in the art. For example, when the power cable according to the present invention is used for a purpose requiring layingability, flexibility, etc., such as a submarine cable, the central conductor layer 10 is preferably made of a stranded wire having excellent flexibility rather than a single wire.

The inner semiconducting layer 20 is disposed between the central conductor layer 10 and the insulating layer 30 to eliminate an air layer causing interlayer floatation between the central conductor layer 10 and the insulating layer 30. , and relieves local electric field concentration. Meanwhile, the outer semiconducting layer 40 functions to apply an equal electric field to the insulating layer 30 , relaxes local electric field concentration, and protects the cable insulating layer from the outside.

In general, the inner semiconducting layer 20 and the outer semiconducting layer 40 are formed by extrusion of a semiconducting composition in which conductive particles such as carbon black, carbon nanotubes, carbon nanoplates, and graphite are dispersed in a base resin, The base resin is an olefin resin of the same series as the base resin of the insulating composition forming the insulating layer 30 for interlayer adhesion between the semiconducting layers 20 and 40 and the insulating layer 30, for example, an olefin. It is preferable to use a copolymer resin of an acrylic monomer and, in particular, ethylene butyl acrylate (EBA), ethylene ethyl acrylate (EEA), or the like.

The thickness of the inner and outer semiconducting layers 20 and 40 may be different depending on the transmission voltage of the cable. For example, in the case of a 345 kV power cable, the thickness of the inner semiconducting layer 20 is 1.6 to 1.8 mm. The thickness of the outer semiconducting layer 40 may be 1.02 to 2.54 mm.

The insulating layer 30 may be, for example, a polyolefin resin such as polyethylene or polypropylene as a base resin, and may preferably be formed by extrusion of an insulating composition including a polyethylene resin.

The polyethylene resin may be ultra low density polyethylene (ULDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), or a combination thereof. In addition, the polyethylene resin may be a homopolymer, a random or block copolymer of ethylene and an α-olefin such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene, or a combination thereof.

In addition, since the insulating composition forming the insulating layer 30 contains a crosslinking agent, the insulating layer 30 is formed by crosslinking polyolefin (XLPO), preferably crosslinked polyethylene (XLPE) during extrusion or after extrusion by a separate crosslinking process. ) can be made. In addition, the insulating composition may further include other additives such as antioxidants, extrudability improvers, and crosslinking aids.

The crosslinking agent is a silane-based crosslinking agent, or dicumyl peroxide, benzoyl peroxide, lauryl peroxide, t-butyl cumyl peroxide, di(t-butyl peroxyisopropyl) benzene, 2,5 depending on the crosslinking method of the polyolefin. - It may be an organic peroxide-based crosslinking agent such as dimethyl-2,5-di(t-butyl peroxy)hexane or di-t-butyl peroxide. Here, the crosslinking agent may be included in an amount of 1 to 5 parts by weight based on 100 parts by weight of the base resin.

The thickness of the insulating layer 30 may be different depending on the transmission voltage of the power cable. For example, in the case of a 345 kV power cable, the thickness of the insulating layer 30 may be 27.45 to 34.55 mm.

The metal layer 50 is formed by a plurality of neutral wires made of a metal, preferably copper, a first semiconducting layer 45 formed by transversely winding a first semiconducting tape on its lower portion, and a second semiconducting tape on its upper portion The second semiconducting layer 55 formed by being transversely wound may be formed, and serves to protect the cable under severe environmental conditions such as the seabed.

The first semiconducting layer 45 performs buffering to suppress deformation of the insulating layer 30 due to the load of the metal layer 50 , and the second semiconducting layer 55 is formed of the metal layer 50 . perform binding. In addition, the first and second semiconducting layers 45 and 55 may be wet and swollen tapes, and in this case, a water blocking function may be performed in parallel. The thickness of the first and second semiconducting tapes may be, for example, about 200 to 1,000 μm.

The thickness of the metal layer 50 may be, for example, about 2.2 to 2.4 mm, and the thickness of the first and second semiconducting layers 45 and 55 may be, for example, about 0.85 to 0.95 mm.

The watertight layer 60 may be made of a metal, preferably a metal material of the same series as that of the metal layer 50 , for example, copper, and in particular, may be formed of a copper tape. The watertight layer 60 functions to suppress the penetration of moisture penetrating through the jacket layer 80 into the insulating layer 30 . In addition, when the watertight layer 60 is made of a metal material of the same series as the metal layer 50, for example, copper (Cu), galvanic corrosion between the watertight layer 60 and the metal layer 50 ( In addition to suppressing galvanic corrosion, the watertight layer 60 may assist the electrical characteristics of the metal layer 50 .

Here, the copper tape forming the watertight layer 60 has the advantage of superior corrosion resistance compared to the conventional aluminum foil layer and light weight compared to the conventional lead foil layer, and the thickness thereof may be, for example, about 0.1 to 0.25 mm. have.

FIG. 5 schematically enlarges the cross-sectional structure of the overlapping portion 61 of the watertight layer 60 in FIG. 4 .

As shown in FIGS. 4 and 5 , both ends of the watertight layer 60 may overlap to implement better watertight characteristics, and the lower surface and upper surface of both ends of the watertight layer overlapping in the overlapping region. The silver may be tightly adhered by a hot melt adhesive 62 . The hot melt adhesive 62 is a hot melt adhesive that exhibits adhesive force while cooling and solidifying within a few seconds after application and compression in a liquid state at a high temperature using 100% thermoplastic resin without using any water or solvent.

The hot-melt adhesive 62 does not require a drying process compared to other solvent-type adhesives or water-dispersion adhesives, and has a small working space and a fast bonding speed. In addition, the material of the hot melt adhesive may be, for example, polyurethane, polyamide, polyester, polyethylene vinyl acetate, rubber, and the like, and in general, may further include a wax, an adhesive, a plasticizer, a filler, an antioxidant, and the like.

The hot melt adhesive 62 is preferably made of a polyamide series having a creep resistance temperature and a softening temperature of 80° C. or higher for use in a power cable, for example, Henkel ( Q8740 or Q6239 commercially available from Henkel) can be purchased and used.

As shown in FIG. 5 , an auxiliary adhesion layer 65 may be formed on the watertight layer 60 . Since the adhesion of the water-tight layer 60 and the adhesive layer 70 may not be easy, the adhesion auxiliary layer 65 made of a resin that is easily adhered to the adhesive layer 70 is applied to the water-tight layer 60, For example, lamination over copper tape. The thickness of the auxiliary adhesive layer 65 may be, for example, about 0.05 to 0.09 mm.

A method of laminating the auxiliary adhesive layer 65 is not particularly limited, and for example, deposition, electro deposition, extrusion, or the like may be used. The auxiliary adhesion layer 65 has a function of maintaining a close adhesion between the watertight layer 60 and the jacket layer 80 even under severe conditions in which an impact is applied from the outside of the cable or a sudden temperature change, and the watertight layer ( 60) performs a function of inhibiting corrosion of the copper tape forming.

Here, the auxiliary adhesion layer 65 is the residual ratio of the peel force of the jacket layer 80 with respect to the watertight layer 60 measured after immersing the power cable in a basic aqueous solution having a pH of 8.5 and a temperature of 80° C. for 7 days. It may be made of an adhesive having an adhesive force of % or more. The peel force residual ratio is the jacket layer for the water-tight layer 60 after immersion of the power cable with respect to the initial value of the peel force of the jacket layer 80 with respect to the water-tight layer 60 before immersion of the power cable ( 80) means the ratio of the peel force values.

When the residual rate of peel force is less than 70%, close adhesion between the watertight layer 60 and the jacket layer 80 cannot be maintained under severe conditions in which an impact is applied from the outside of the cable or the temperature is rapidly changed.

For example, the adhesion auxiliary layer 65 may be formed of an adhesive including an acrylic resin, an olefin-based resin, preferably, a random copolymer resin of an olefin and a polar monomer as a base resin. The adhesive auxiliary layer 65 may be formed by a general coating process such as spraying, impregnation, or extrusion.

The polar monomer may include vinyl ester monomers such as vinyl acetate and vinyl versatate; vinyl-unsaturated carboxylic acid monomers such as methacrylic acid, acrylic acid, maleic acid, and itaconic acid; It may include an acrylic monomer such as (meth)acrylate and alkyl (meth)acrylate or a combination thereof, and the content of the polar monomer is 5 to 20% by weight, preferably 5 to 20% by weight based on the total weight of the resin. to 15% by weight.

Preferably, the base resin of the adhesive forming the auxiliary adhesive layer 65 may be ethylene acrylic acid (EAA), ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA), or the like.

The adhesive layer 70 performs a function of adhering the watertight layer 60 and the jacket layer 80 and blocks moisture passing through the jacket layer 80 to the watertight layer 60 by the moisture. It performs a function of suppressing the peeling force of the adhesive layer 70 from being lowered.

Here, the adhesive layer 70 may be made of a resin having a density of 0.93 or more, for example, 0.93 to 0.97, and a crystallinity of more than 50%, for example, more than 50% and less than or equal to 90%, whereby the melting point is 100 ° C. Above, for example, may be 100 to 140 ℃.

The adhesive layer 70 has the high density and the high crystallinity, and unlike the jacket layer 80 , an additive such as carbon black that forms a water movement path is not added, so that water-repellent properties are improved, and the water-tight layer is formed by moisture penetration. It can suppress that the peeling force of the said adhesive layer 70 with respect to (60) falls.

In addition, the thickness of the adhesive layer 70 may be 1 to 5 mm, preferably 1 to 3 mm. Here, when the thickness of the adhesive layer 70 is less than 1 mm, the peeling force of the adhesive layer 70 with respect to the water-tight layer 60 may be lowered by moisture penetration because it does not have sufficient water-repellent properties, whereas the When the thickness of the adhesive layer 70 is more than 5 mm, the overall diameter of the power cable is unnecessarily increased, and the protrusion shape of the plurality of neutral wires forming the metal layer 50 by cooling gradually during cooling after extrusion is the jacket layer. (80) may appear on the surface.

The adhesive layer 70 is a resin of the same series as the resin forming the water-tight layer 60 and the jacket layer 80 for close adhesion with the water-tight layer 60 and the jacket layer 80, for example. For example, it may consist of an ethylene homopolymer or copolymer, preferably a high density polyethylene (HDPE) resin.

The jacket layer 80 may include polyethylene, polyvinyl chloride, polyurethane, etc., in order to maintain close adhesion with the adhesive layer 70, a resin of the same series as the resin constituting the adhesive layer 70; For example, it is preferably made of a polyethylene resin, and since it is a layer disposed at the outermost part of the cable, considering the mechanical strength, it is more preferably made of a high-density polyethylene (HDPE) resin. In addition, the jacket layer 80 may contain a small amount of an additive such as carbon black, for example, 2 to 3% by weight in order to realize the color of the power cable.

The jacket layer 80 preferably has a thickness of, for example, 5 to 8 mm in order to absorb the impact when an impact is applied to the cable from the outside to maintain close adhesion with the adhesive layer 70 .

As described above, the power cable according to the present invention forms the base layer of the watertight layer 60 with copper tape, which is lightweight compared to conventional lead and has excellent corrosion resistance compared to conventional aluminum, so that it is lightweight compared to conventional power cables and has excellent corrosion resistance. Do.

In addition, precisely controlling the adhesive force of the adhesive auxiliary layer 65 forming the water-tight layer 60, and the density and crystallinity of the adhesive layer 70 for bonding the water-tight layer 60 and the jacket layer 80, and By precisely controlling the thickness of the adhesive layer 70, it exhibits an excellent effect of closely maintaining the adhesion between the layers constituting the cable despite external physical impact and temperature change.

The power cable according to the present invention protects the watertight layer 60 from external impact on the cable and maintains the adhesive force between the watertight layer 60 and the adhesive layer 70 even when the external impact is applied. A buffer layer (not shown) may be further included.

The buffer layer is disposed between the water-tight layer 60 and the adhesive layer 70 to absorb external impact on the cable, thereby preventing damage to the water-tight layer 60, particularly the copper tape, and suppressing delamination between layers. carry out

In particular, when the external impact on the cable exceeds the extent to which it can be absorbed by the buffer layer, a part of the impact is transmitted to the watertight layer 60 , in particular the copper tape, so that the copper tape is partially depressed. formed, and the depression may be a passage for moisture penetrating from the outside to move in the longitudinal direction of the cable, and the buffer layer contains a softer resin compared to the adhesive layer 70 to fill the depression so that moisture is transferred to the length of the cable. A function of inhibiting movement in the direction may be additionally performed.

On the other hand, in the conventional power cable not having the buffer layer, when an impact is applied from the outside during its installation, the impact is transmitted to the water-tight layer and delamination may occur. In particular, when a depression is formed in the water-tight layer, the depression is external It can be a passage through which moisture permeated from the inside moves in the longitudinal direction.

The buffer layer preferably includes a resin having a melting point of 80° C. or more, a density of 0.85 to 0.94, and a hardness (shore A) of 65 or more to withstand heat generated during operation of the cable. If the density of the resin constituting the buffer layer is less than 0.85 and the hardness (shore A) is less than 65, it cannot sufficiently absorb the external shock to the cable, whereas if the density is more than 0.94, it will be formed on the copper tape by external shock. The dent cannot be filled sufficiently.

Since the buffer layer is disposed between the watertight layer 60, in particular, the adhesion auxiliary layer 65 and the adhesive layer 70, in order to suppress delamination, the resin included in the buffer layer is applied to the adhesion auxiliary layer 65. It is preferable that the resin included and the resin included in the adhesive layer 70 have advantageous adhesion and compatibility.

The resin included in the buffer layer is, for example, an ethylene copolymer, preferably one or more ethylene copolymers selected from the group consisting of ethylene butyl acrylate (EBA), ethylene vinyl acetate (EVA), ethylene acrylic acid (EAA), and the like. It may include, and may also include a copolymer of ethylene and α-olefins such as 1-butene, 1-hexene, 1-octene, or rubber series.

The thickness of the buffer layer may be 1 to 3 mm. The buffer layer absorbs an external shock to the cable when its thickness is less than 1 mm on the premise that the thickness of the adhesive layer 70 is as described below, and is insufficient to fill the depression of the watertight layer formed by the external shock. , if the thickness is more than 3 mm, the outer diameter of the cable may increase unnecessarily.

The present invention relates to a method of manufacturing a power cable. The method of manufacturing a power cable according to the present invention includes a conductor layer 10, an inner semiconducting layer 20 surrounding the conductor layer 10, an insulating layer 30 surrounding the inner semiconducting layer 20, and the insulating layer ( 30) comprising the step of forming an outer semiconducting layer 40 surrounding the outer semiconducting layer 40 and a metal layer 50 surrounding the outside of the outer semiconducting layer 40, and an adhesion auxiliary layer 55 on the outside of the metal layer 50 is an upper surface A watertight layer forming step of forming a watertight layer 60 by attaching the overlapping portions of both ends of the metal tape to the ends of the laminated metal tape, the adhesive auxiliary layer 55 on the outside of the adhesive auxiliary layer 55 An adhesive layer forming step of extruding the adhesive layer 70 at an extrusion temperature above the melting point, and a jacket layer 80 forming step of extruding the jacket layer 80 at an extrusion temperature above the melting point of the adhesive layer 70 to the outside of the adhesive layer 70 may include

In addition, the method of manufacturing a power cable according to the present invention comprises a first semiconducting layer forming step of forming a first semiconducting layer surrounding the outer semiconducting layer 40 with a first semiconducting tape before the watertight layer forming step, the A second semiconducting layer forming step of forming a second semiconducting layer surrounding the metal layer 50 with a second semiconducting tape before the watertight layer forming step may be further included.

Furthermore, in the watertight layer forming step, the overlapping portion may be adhered with a hot melt adhesive having a creep resistance temperature or softening point of 80° C. or higher, and in the adhesive layer forming step, the density is 0.93 or higher and the crystallinity is greater than 50% By extrusion of a resin The adhesive layer 70 may be formed.

[Example]

1. Preparation example

Adhesive layer (high-density polyethylene with a density of 0.956), copper tape, and adhesive auxiliary layer (ethylene vinyl acetate) through hot pressing under the conditions of a press temperature of 160°C (10 minutes), a cooling temperature of 40°C (10 minutes), and a pressure of 4,800 kg/m2. ), an adhesive layer (high-density polyethylene with a density of 0.956) and an outer jacket (high-density polyethylene, 2.5 wt% of carbon black) were sequentially laminated to prepare a sample sheet of Example 1 formed. In addition, sample sheets of Examples and Comparative Examples in which litmus paper was inserted between two adhesive layer specimens shown in Table 1 below were prepared.

Suzy Thickness (mm) Example 2 resin 1 1.0 Example 3 resin 1 2.0 Comparative Example 1 resin 1 0.25 Comparative Example 2 resin 1 0.5 Comparative Example 3 resin 2 0.25 Comparative Example 4 resin 2 0.5 Comparative Example 5 resin 2 1.0 Comparative Example 6 resin 2 2.0

- Resin 1: high density polyethylene (density 0.956)

- Resin 2: ethylene/acrylic acid random copolymer resin (density 0.927)

2. Physical property evaluation

1) Peel force evaluation

The peel force of the outer jacket to the copper tape was measured before and after the sample sheet of Example 1 was immersed in a basic aqueous solution having a pH of 8.5 and a temperature of 80°C. The peel force measurement results are shown in Table 2 below.

before submersion 7 days after submersion 21 days after submersion 42 days after submersion 84 days after submersion Peel force (N/mm) 0.86 0.80 0.77 0.78 0.77 Residual peel force (%) 100 93 90 91 90

As shown in Table 2, the power cable of Example 1 according to the present invention has excellent water-repellent properties and adhesion of the adhesive layer, so that even after submersion, the interlayer adhesion between the water-tight layer and the outer jacket was maintained at 70% or more compared to before submersion. Confirmed.

2) Water permeation evaluation

After immersing the specimens of Examples 2 and 3 and Comparative Examples 1 to 6 in a basic aqueous solution having a pH of 8.5 and a temperature of 80° C., the time until the basic solution passed through the adhesive layer specimen to discolor the litmus paper was measured. The evaluation results are shown in Table 3 below.

time to water penetration Example 2 more than 125 days Example 3 more than 125 days Comparative Example 1 7 days Comparative Example 2 48 days Comparative Example 3 0 days Comparative Example 4 3 days Comparative Example 5 12 days Comparative Example 6 19th

As shown in Table 3, the adhesive layers of Examples 2 and 3 according to the present invention were confirmed to have sufficient water resistance because they were made of a resin having a density of 0.93 or more and had a thickness greater than or equal to a specific value.

On the other hand, it was confirmed that the adhesive layers of Comparative Examples 1 to 4 had insufficient water resistance because the thickness was less than the critical value, and the adhesive layers of Comparative Examples 5 and 6 had insufficient water resistance because the density of the resin constituting them was less than the critical value.

Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims described below. will be able to carry out Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all of them should be considered to be included in the technical scope of the present invention.

10: conductor 20: inner semiconducting layer
30: insulating layer 40: outer semiconducting layer
50, 70: semi-conductive tape layer 60: metal layer
80: watertight layer 90: adhesive layer
100: outer jacket

Claims (26)

central conductor layer;
an inner semiconducting layer positioned outside the central conductor layer;
an insulating layer positioned outside the inner semiconducting layer;
an outer semiconducting layer positioned outside the insulating layer;
a metal layer positioned outside the outer semiconducting layer and made of a plurality of metal wires;
a watertight layer positioned outside the metal layer;
an adhesive layer positioned outside the watertight layer; and
It includes a jacket layer located outside the adhesive layer,
The adhesive layer comprises a high-density polyethylene (HDPE) resin having a density of 0.93 or more and a crystallinity of more than 50%,
Power cable, characterized in that the thickness of the adhesive layer is 1 to 5 mm. According to claim 1,
a first semiconducting layer located between the outer semiconducting layer and the metal layer;
a second semiconducting layer located between the metal layer and the watertight layer; and
Power cable, characterized in that it further comprises an auxiliary adhesive layer located between the watertight layer and the adhesive layer. 3. The method of claim 2,
The watertight layer has a thickness of 0.1 to 0.25 mm, and the thickness of the auxiliary adhesive layer is 0.05 to 0.09 mm, the power cable. 3. The method of claim 2,
The adhesive forming the auxiliary adhesive layer is characterized in that it comprises a copolymer or blend resin of an olefin and a polar monomer, power cable. 5. The method of claim 4,
The polar monomer is a vinyl ester monomer of vinyl acetate or vinyl versatate, a vinyl-unsaturated carboxylic acid monomer of methacrylic acid, acrylic acid, maleic acid or itaconic acid, (meth) acrylate or an acrylic monomer of alkyl (meth) acrylate. Characterized by the power cable. 6. The method of claim 5,
The power cable, characterized in that the random copolymer resin of the olefin and the polar monomer is ethylene acrylic acid (EAA), ethylene vinyl acetate (EVA) or ethylene butyl acrylate (EBA). 7. The method of claim 6,
The content of the polar monomer, based on the total weight of the random copolymer resin, characterized in that 5 to 20% by weight, the power cable. 8. The method according to any one of claims 1 to 7,
The watertight layer is characterized in that it comprises a metal material of the same series as the metal layer, the power cable. 9. The method of claim 8,
Power cable, characterized in that the watertight layer comprises copper (Cu) 8. The method according to any one of claims 2 to 7,
The watertight layer is formed by terminating the metal tape on which the adhesive auxiliary layer is laminated, and both ends are overlapped, the power cable. 11. The method of claim 10,
Power cable, characterized in that the two ends of the watertight layer are adhered by a hot melt adhesive in an overlapping region. 12. The method of claim 11,
The power cable, characterized in that the hot melt adhesive has a creep resistance temperature and a softening temperature of 80° C. or higher. 13. The method of claim 12,
The hot melt adhesive comprises a polyamide resin, a polyethylene vinyl acetate resin, or both, the power cable. delete delete 8. The method according to any one of claims 1 to 7,
The power cable, characterized in that the adhesive layer does not contain an additive capable of forming a moisture migration path. delete According to claim 1,
The power cable, characterized in that the thickness of the adhesive layer is 1 to 3 mm. 8. The method according to any one of claims 1 to 7,
The jacket layer comprises a high-density polyethylene (HDPE) resin, characterized in that the thickness of 5 to 7.5 mm, power cable. 3. The method of claim 2,
The adhesive auxiliary layer includes an adhesive having an adhesive strength such that the residual rate of peel force of the jacket layer with respect to the watertight layer measured after immersing the power cable in a basic aqueous solution of pH 8.5 and a temperature of 80 ° C. characterized in that, the power cable. 8. The method according to any one of claims 1 to 7,
Power cable, characterized in that it further comprises a buffer layer for absorbing an external impact to the cable between the watertight layer and the adhesive layer. In a method of manufacturing a power cable comprising a conductor layer, an inner semiconducting layer surrounding the conductor layer, an insulating layer surrounding the inner semiconducting layer, an outer semiconducting layer surrounding the insulating layer, and a metal layer surrounding the outside of the outer semiconducting layer,
A watertight layer forming step of forming a watertight layer by attaching a metal tape having an adhesive auxiliary layer laminated on the upper surface to the outside of the metal layer, but adhering overlapping portions of both ends of the metal tape to the ends;
An adhesive layer forming step of extruding the adhesive layer to the outside of the adhesive auxiliary layer at an extrusion temperature equal to or higher than the melting point of the auxiliary adhesive layer, and
A jacket layer forming step of extruding the jacket layer to the outside of the adhesive layer at an extrusion temperature equal to or higher than the melting point of the adhesive layer,
The adhesive layer comprises a high-density polyethylene (HDPE) resin having a density of 0.93 or more and a crystallinity of more than 50%,
The method of manufacturing a power cable, characterized in that the thickness of the adhesive layer is 1 to 5 mm. 23. The method of claim 22,
The method of claim 1, further comprising a first semiconducting layer forming step of forming a first semiconducting layer surrounding the outer semiconducting layer with a first semiconducting tape before the watertight layer forming step. 24. The method of claim 22 or 23,
Method of manufacturing a power cable, characterized in that it further comprises a second semiconducting layer forming step of forming a second semiconducting layer surrounding the metal layer with a second semiconducting tape before the watertight layer forming step. 24. The method of claim 22 or 23,
The method of manufacturing a power cable, characterized in that the overlapping portion is bonded with a hot melt adhesive having a creep resistance temperature or softening point of 80° C. or more in the watertight layer forming step. delete

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