JP2012028196A - Electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric wire of a structure capable of reusing a regenerated material in which waste material of an internal semiconductive layer or an external semiconductive layer is mixed.SOLUTION: An electric wire 1A comprises a conductor 11, a regenerated material layer 12 provided on an outer peripheral portion of the conductor 11 and made from regenerated material mixed resin, an insulation layer 14 provided on an outer peripheral portion of the regenerated material layer 12 and made from a polyolefin (system) resin which is not a regenerated material, and a sheath 17 provided on an outer peripheral portion of the insulation layer 14. The insulation layer 14 exists on the outside of the regenerated material layer 12, therefore the whole of the electric wire 1A can sufficiently ensure electric performance such as pressure resistance and insulation resistance.

Description

  The present invention relates to an electric wire using a so-called recycled material.

  As an electric wire, (1) an insulated wire in which the outer periphery of the conductor is covered with an insulating layer, (2) a power cable in which the insulated wire is covered with an insulation core, and this is further covered with a sheath, (3) an inner semiconductive layer is provided on the outer periphery of the conductor There is known a power cable provided with an outer semiconductive layer covered with an insulating layer and an outer semiconductive layer, a shielding layer, and a sheath provided on the outer periphery of the insulating layer.

  In addition, recycled materials (so-called recycled materials) that are recycled from the waste material of crosslinked polyolefin (based) resin used in the insulation layer of (1) insulated wires and (2) power cables, and recycled materials A technique is known in which an insulator is formed again with a recycled material mixed resin obtained by mixing a non-polyolefin resin (see, for example, Patent Document 1).

JP 2006-66262 A

  However, when the insulating layer of the power cable (3) is reused, it is inevitable that waste materials of the internal semiconductive layer and the external semiconductive layer are mixed. Since the internal semiconductive layer and external semiconductive layer are made of a semiconductive material by blending carbon or the like with a cross-linked polyolefin (based) resin, etc., recycled materials mixed with waste materials from the internal semiconductive layer and external semiconductive layer Is subjected to a thermoplastic treatment, the volume resistivity ρ of the recycled material is lowered, and the volume resistivity varies. For this reason, it has become an obstacle to the reuse of recycled materials in which waste materials of the internal semiconductive layer and the external semiconductive layer may be mixed.

  An object of the present invention is to provide an electric wire having a structure that can be reused even with recycled materials that may have been mixed with waste materials of an internal semiconductive layer or an external semiconductive layer.

  In order to solve the above problems, the invention according to claim 1 is directed to a conductor, a recycled material layer provided on an outer periphery of the conductor, made of recycled material or a recycled material mixed resin, and an outer periphery of the recycled material layer. And an insulating layer made of a polyolefin (based) resin that is not a recycled material, and a sheath.

In the present application, the recycled material is a recycled material of a cross-linked polyolefin (based) resin so that it can be thermoplasticized.
In the present application, the crosslinked polyolefin (based) resin is obtained by crosslinking one or more kinds of resins selected from polyolefin resins or polyolefin resins. The cross-linked polyolefin (based) resin may be obtained by any cross-linking method. For example, a cross-linked polyolefin resin using a cross-linking agent such as an organic peroxide or a silane compound, a cross-linked one using an electron beam, or the like can be used. .
In the present application, the polyolefin (based) resin is used in the meaning including the polyolefin resin and the polyolefin based resin.
Examples of the polyolefin resin include high density polyethylene, linear low density polyethylene, low density polyethylene, and polypropylene.
Examples of the polyolefin resin include ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid ester copolymer, ethylene- (meth) acrylic acid copolymer, and the like.
In the present application, the recycled material mixed resin is a mixture of recycled material and polyolefin (based) resin that is not recycled material. As the polyolefin (based) resin that is not a recycled material, various resins can be used as long as they have not been cross-linked, but a resin that has never been molded after production (so-called virgin material) is preferable. Used for.

  The invention according to claim 2 is provided on the outer periphery of the conductor, the recycled material layer made of the recycled material or the recycled material mixed resin, and on the outer circumferential portion of the recycled material layer, and is not the recycled material. A semiconductive coating layer formed of a semiconductive resin composition made of a polyolefin (based) resin, an insulating layer made of a polyolefin (based) resin that is provided on the outer periphery of the semiconductive coated layer and is not a recycled material, An electric wire comprising a sheath.

  Note that an outer semiconductive layer made of a semiconductive resin composition is provided on the outer peripheral portion of the insulating layer of the electric wire, a shielding layer is provided on the outer peripheral portion of the outer semiconductive layer, and a sheath is provided on the outer peripheral portion of the shielding layer. good.

The invention according to claim 3 includes a conductor, a recycled material layer made of recycled material or a recycled material mixed resin, and a sheath provided on the outer circumferential portion of the recycled material layer, provided on the outer circumferential portion of the conductor. A volume resistivity of the recycled material or recycled material mixed resin is 2.5 × 10 ¹⁵ [Ω / m] or more.

  ADVANTAGE OF THE INVENTION According to this invention, the electric wire of the structure which can recycle the recycled material in which the waste material of the internal semiconductive layer and the external semiconductive layer was mixed can be provided.

It is a sectional view showing electric wire 1A concerning a 1st embodiment of the present invention. It is sectional drawing which shows the electric wire 1B which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows 1 C of electric wires which concern on the 3rd Embodiment of this invention. It is sectional drawing which shows electric wire 1D which concerns on the 4th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
[First Embodiment]
FIG. 1 is a cross-sectional view showing an electric wire 1A according to the first embodiment of the present invention. As shown in FIG. 1, the electric wire 1 </ b> A includes a conductor 11, a recycled material layer 12, an insulating layer 14, and a sheath 17.
For the conductor 11, for example, a copper wire, an aluminum wire or the like can be used.

  The recycled material layer 12 is formed outside so as to cover the conductor 11. In order to form the recycled material layer 12, a recycled material mixed resin obtained by mixing a recycled material obtained by regenerating a waste material of a crosslinked polyolefin (based) resin so as to be thermoplasticized and a polyolefin (based) resin that is not a recycled material is used.

  The cross-linked polyolefin (system) waste material is a waste material of the cross-linked polyolefin (system) resin. Examples of the cross-linked polyolefin (system) waste include, for example, coating waste of wiring materials such as wire covering waste, pipes for water supply, hot water supply, indoor heating, and various foams discarded as general waste. .

Here, an example of a method for regenerating the crosslinked polyolefin (system) waste material so that it can be thermoplasticized into a recycled material will be described.
First, the cross-linked polyolefin (system) waste material is put into the same-direction meshing twin-screw extruder, and the cross-linking is cut (thermoplastic treatment) to obtain a recycled material.

  The gel fraction of the recycled material that has been subjected to the thermoplastic treatment is preferably 40% or less, and more preferably 10% or less. Here, the gel fraction is a ratio of the mass of the sample that remains without being dissolved in the heated xylene to the mass of the original sample. The gel fraction can be measured by “4.25 degree of crosslinking” in JIS C 3005.

By performing the thermoplastic treatment under the appropriate conditions with the same-direction meshing twin screw extruder, the gel fraction of the recycled material can be reduced to 40% or less. A preferable processing temperature is 250 ° C. to 400 ° C., and a preferable shear rate is 200 sec ⁻¹ or more. Here, the shear rate is a numerical value obtained by dividing the peripheral speed (mm / s) of the outermost peripheral part of the screw element of the same-direction meshing twin-screw extruder by the clearance (mm) between the screw and the barrel.

  Next, the obtained recycled material is mixed with a polyolefin (based) resin that is not a recycled material to obtain a recycled material mixed resin. The mixing ratio of the recycled material is 50% by mass or less, preferably 40% by mass or less of the total resin amount. However, 0 mass% is not included.

  As the polyolefin (based) resin that is not a recycled material, various resins can be used as long as they have not been cross-linked, but a resin that has never been molded after production (so-called virgin material) is preferable. Used for. As the polyolefin (based) resin that is not a recycled material, one kind or a mixture of two or more kinds of polyolefin resins or polyolefin resins can be used. Among these, it is preferable to use high density polyethylene, linear low density polyethylene, and low density polyethylene. Specifically, a polyethylene resin (NUCG9301, manufactured by Dow Chemical Co., Ltd.) can be used.

  The insulating layer 14 is provided on the outside so as to cover the recycled material layer 12. For the insulating layer 14, a polyolefin (based) resin that is not a recycled material is used.

  For the recycled material layer 12 and the insulating layer 14, an additive used for forming a normal insulating layer can be used. Specifically, an appropriate amount of a crosslinking agent, a crosslinking aid, an antioxidant, an ultraviolet absorber, and the like can be added as necessary.

  The sheath 17 is provided outside so as to cover the insulating layer 14. For the sheath 17, for example, vinyl chloride or the like can be used.

Here, an example of the manufacturing method of the electric wire 1A will be described.
The insulation layer made of cross-linked polyethylene is recovered from the removed power cable, and this is cut in the same direction meshing type twin screw extruder at a processing temperature of 300 ° C. and a shear rate of 500 sec ⁻¹ to obtain a gel fraction. 35% recycled material was used. The power cable has an internal semiconductive layer and an external semiconductive layer inside and outside the insulating layer, and the semiconductive layer was mixed in the collected insulating layer.
This recycled material and low density polyethylene, which is a polyolefin resin that is not a recycled material, were mixed at a weight ratio of 50:50 to produce a pelletized recycled material mixed resin.
The recycled material mixed resin, which is the material of the recycled material layer 12 obtained in this way, was charged into the hopper of the first extruder. Further, a resin composition made of polyethylene which is not a recycled material, which is a material of the insulating layer 14, is put into a hopper of a second extruder, both are connected by a crosshead, and the recycled material mixed resin is pushed out around the conductor 11. At the same time, polyethylene that was not recycled was extruded around it.

  Thus, the recycled material layer 12 and the insulating layer 14 are formed on the outer peripheral portion of the conductor 11. Thereafter, the sheath 17 is formed on the outer peripheral portion of the insulating layer 14 to complete the electric wire 1A.

  The recycled material layer 12 of the electric wire 1A thus manufactured has a reduced volume resistivity ρ and a variation in volume resistivity. For this reason, as shown schematically by broken lines in FIG.

  However, in the electric wire 1A according to the present invention, since the insulating layer 14 is present outside the regenerated material layer 12, problems of deformation of the equipotential surface L and variations in the volume resistivity ρ of the regenerated material layer 12 become obvious at low pressure. There is nothing to do. That is, since the insulating layer 14 is present outside the recycled material layer 12, the electric wire 1A as a whole can sufficiently ensure electrical performance such as pressure resistance and insulation resistance. Therefore, if the electric wire has the structure of this embodiment, it is possible to use a recycled material in which a semiconductive material may be mixed.

In addition, you may form the recycled material layer 12 of the electric wire of the said embodiment only with a recycled material.
The resin forming the recycled material layer 12 and the insulating layer 14 may be cross-linked. What is necessary is just to select a normal crosslinking method suitably as a crosslinking method. For example, “peroxide crosslinking method” in which an organic peroxide is added and heated after extrusion, “silane crosslinking method” in which a silane compound and a crosslinking aid are added and extruded and then crosslinked with moisture, electron beam irradiation The “electron beam crosslinking method” and the like.

[Second Embodiment]
FIG. 2 is a sectional view showing an electric wire 1B according to the second embodiment of the present invention. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is omitted.
The electric wire 1 </ b> B further includes an outer semiconductive layer 15 and a shielding layer 16 between the insulating layer 14 and the sheath 17 in addition to the conductor 11, the recycled material layer 12, the insulating layer 14, and the sheath 17.

  The external semiconductive layer 15 is provided outside so as to cover the insulating layer 14 and is made of a semiconductive resin composition. The semiconductive resin composition is obtained by appropriately mixing carbon black for imparting conductivity and other blends with a base resin made of a polyolefin (based) resin such as an ethylene-vinyl acetate copolymer. Nitrile butadiene rubber or the like may be mixed with the base resin.

  The carbon black may be any known carbon black and is not particularly limited. For example, furnace black, acetylene black, ketjen black and the like can be exemplified, and these may be used alone or in combination.

  As other blends, the semiconductive resin composition can be blended with other additives such as a crosslinking agent and an anti-aging agent. As the anti-aging agent, a commonly used anti-aging agent can be appropriately selected and blended, and it is preferable to blend a phenol-based, phosphite-based, or thioether-based anti-aging agent. Moreover, it is preferable to mix | blend 4,4-thiobis (3-methyl-6-tert- butylphenol) as an anti-aging agent at the point which has the crosslinking reaction inhibitory effect of the resin composition at the time of extrusion.

  The shielding layer 16 is provided outside so as to cover the external semiconductive layer 15. The shielding layer 16 can be formed by, for example, winding a copper tape around the outer periphery of the external semiconductive layer 15.

  Even in the present embodiment, even if the volume resistivity ρ of the recycled material layer 12 is small, the insulating layer 14 is present outside the recycled material layer 12, so that for the low voltage, the electric wire 1B as a whole has an electrical resistance such as withstand voltage and insulation resistance. Sufficient performance can be ensured.

[Third Embodiment]
FIG. 3 is a sectional view showing an electric wire 1C according to the third embodiment of the present invention. In addition, about the structure similar to 2nd Embodiment, the same code | symbol is attached | subjected and description is omitted.

In addition to the conductor 11, the recycled material layer 12, the insulating layer 14, the outer semiconductive layer 15, the shielding layer 16, and the sheath 17, the electric wire 1 </ b> C has a semiconductive coating layer 13 between the recycled material layer 12 and the insulating layer 14. Is further provided.
In this embodiment, the recycled material layer 12 is formed only of the recycled material.
The semiconductive coating layer 13 is a layer formed of a semiconductive resin composition, and is provided so as to cover the recycled material layer 12. The semiconductive resin composition is made of the same material as that of the external semiconductive layer 15 described above.
In order to form the semiconductive coating layer 13, a semiconductive resin composition made of a polyolefin (based) resin that is not a recycled material is used. In particular, it is desirable to use a resin that has never been molded.

  Even in the present embodiment, even if the volume resistivity ρ of the recycled material layer 12 is small, the insulation layer 14 is present outside the recycled material layer 12, so that the electric wire 1A as a whole has sufficient electrical performance such as pressure resistance and insulation resistance. Can be secured.

  Furthermore, in this embodiment, since the semiconductive coating layer 13 is provided outside the recycled material layer 12, the unevenness of the equipotential surface in the recycled material layer 12 due to the variation in the volume resistivity ρ of the recycled material is semiconductive. The surface of the recycled material layer 12 is covered with the semiconductive coating layer 13 while being relaxed by the conductive coating layer 13. As a result, the equipotential surface coincides with the interface between the semiconductive coating layer 13 and the insulating layer 14, and the equipotential surface can be made smooth. Therefore, it is possible to use a recycled material that may contain a lot of conductive material.

  In the electric wire of this embodiment, the recycled material layer 12 is formed only from the recycled material, but the recycled material layer 12 may be formed from a recycled material mixed resin.

[Fourth Embodiment]
FIG. 4 is a sectional view showing an electric wire 1D according to the fourth embodiment of the present invention. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is omitted.
The electric wire 1D includes the conductor 11, the recycled material layer 12, and the sheath 17, but does not have the insulating layer.

In the present embodiment, the volume resistivity of the recycled material mixed resin that is the material of the recycled material layer 12 is adjusted to be 2.5 × 10 ¹⁵ [Ω / m] or more. The volume resistivity can be adjusted by the mixing ratio of the recycled material and the polyolefin (based) resin that is not the recycled material. By setting the volume resistivity to 2.5 × 10 ¹⁵ [Ω / m] or more, the electric wire 1D as a whole can satisfy the insulation resistance standard value (JIS C3606, etc.) of a general low-pressure crosslinked polyethylene insulated cable. .

1A, 1B, 1C, 1D Electric wire 11 Conductor 12 Recycled material layer 13 Semiconductive coating layer 14 Insulating layer 15 External semiconductive layer 16 Shielding layer 17 Sheath L Equipotential surface

Claims (3)

Conductors,
A recycled material layer provided on the outer periphery of the conductor, made of recycled material or recycled material mixed resin;
An insulating layer made of a polyolefin (based) resin that is not a recycled material, provided on the outer periphery of the recycled material layer;
An electric wire comprising a sheath. The electric wire according to claim 1,
An electric wire characterized in that the outer periphery of the recycled material layer is covered with a semiconductive coating layer made of a semiconductive resin composition made of a polyolefin (based) resin that is not a recycled material. Conductors,
A recycled material layer provided on the outer periphery of the conductor, made of recycled material or recycled material mixed resin;
A sheath provided on the outer periphery of the recycled material layer,
The electric wire, wherein the recycled material or the recycled material mixed resin has a volume resistivity of 2.5 × 10 ¹⁵ [Ω / m] or more.

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