JP2001067934A - Semiconductive tape for power cable and power cable using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductive tape for a power cable recyclable (that is, easily recoverable from a dismantled cable and reclaimable into an original semiconductive tape) and environmentally friendly because the tape contains no halogen element, and to provide a power cable using it excellent in recyclability, having more reusable members than before. SOLUTION: This semiconductive tape for a power cable is formed by sheeting and cutting out a thermoplastic and semiconductive compound containing a soft thermoplastic resin including no halogen element, an electroconductivity imparting agent and a peeling property imparting agent. In the power cable, a semiconductive layer as a shielding layer is formed of the semiconductive tape for the power cable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a power cable,
The present invention relates to a novel semiconductive tape for a power cable, which is suitably used for forming an inner or outer semiconductive layer, and which can be reused and reused, and a power cable using the same.

[0002]

2. Description of the Related Art As shown in FIG. 1, a power cable generally comprises a conductor 11 formed of a plurality of soft copper stranded wires and an inner semiconductive layer 12 made of a cross-linked polyethylene. , An outer semiconductive layer 14, a metal shielding layer 15 formed of a copper tape, and a jacket 16 made of a synthetic resin such as polyvinyl chloride.

[0003] Recently, environmental issues have been taken up greatly. From the viewpoint of recycling, in the case of power cables, the conductor 11 and the metal shielding layer 15 are recovered and reused, but other members are discarded. The fact is that it is. Of these, the inner and outer semiconductive layers 12, 1
No. 4 is generally formed of a semiconductive cloth tape or a semiconductive cross-linked synthetic resin layer coated by extrusion. However, from the viewpoint of recycling, it has the following problems.

That is, a semiconductive cloth tape is generally made of a synthetic rubber such as butyl rubber or ethylene-propylene-diene copolymer rubber, a plasticizer, a conductive carbon black, a non-sulfur vulcanizing agent, a vulcanization aid, and a processing aid. A semiconductive rubber compound formed by kneading various additives such as auxiliaries with a Banbury mixer or an open roll is dissolved in an organic solvent such as toluene, and dispersed to form a rubber coating. It is manufactured by impregnating or coating both sides of a plain woven or non-woven fabric made of fiber or nylon fiber and drying, heating at a high temperature to vulcanize the rubber component, and then cutting into a tape shape.

[0005] Such a semiconductive cloth tape can be recovered by peeling it from the disassembled cable, but in the case of the inner semiconductive layer 12, the wound mark when wound on the conductor 11, The trace of spirally winding and winding
In the case of the external semiconductive layer 14, after winding on the insulator 13, the winding trace of the copper tape when the copper tape is wound thereon to further form the metal shielding layer 15, and the winding itself, Marks of spirally wound windings are remarkably left, and cannot be returned to the original state in which taping can be performed again even if collected.

Further, since the vulcanized semiconductive rubber and the cloth are integrated, they cannot be separated from each other, and the vulcanized rubber cannot be processed such as re-molded, so that it must be reused as a constituent material. I can't do that either.

In the case of a power cable, the external semiconductive layer 14 has a good peeling property with respect to the insulating layer 13 made of cross-linked polyethylene in order to facilitate the connection thereof, so that it can be easily connected at the time of connection. You need to be able to peel it. For this reason, the outer semiconductive layer 14 formed of the latter crosslinked synthetic resin layer is generally composed of a polar synthetic resin such as chlorinated polyethylene, or a nonpolar synthetic resin such as polyethylene, a release agent, and a conductive carbon. Black, organic peroxide as a cross-linking agent, and various additives such as processing aids,
A cross-linkable semiconductive synthetic resin compound formed by kneading with a Banbury mixer or an open roll and cut into pellets is used as an insulator layer 1 during the production of a power cable.
3 is formed by extruding using an extruder and then immediately heating to a high temperature to crosslink the resin.

Therefore, although the crosslinked synthetic resin layer as the external semiconductive layer 14 can be recovered by peeling from the disassembled cable, it cannot be processed again such as reshaping because it is a crosslinked product, and is eventually reused. Can not do. The internal semiconductive layer 12 formed of a crosslinked synthetic resin layer is obtained by cutting a crosslinkable semiconductive synthetic resin compound similar to the above into a pellet shape, and also forming the conductor 11 during the production of a power cable. It is formed by extruding using an extruder and then immediately heating to a high temperature to crosslink the resin so as to coat.

The internal semiconductive layer 12 cannot be separated afterwards because it is integrated with the insulating layer 13 coated thereon, and cannot be processed again such as reshaping because it is a crosslinked material. Can not do it. In addition, among the cross-linked synthetic resin layers, those using a polar synthetic resin such as chlorinated polyethylene contain a halogen element, and may damage the incinerator at the time of combustion, or may generate dioxins, It is not easy to dispose as industrial waste.

As described above, there is a problem that neither the conventional semiconductive cloth tape nor the extrusion-coated semiconductive layer can be recycled or reused when the power cable after use is disassembled. The main object of the present invention is to provide a semi-conductive material for an electric power cable which can be easily recovered from a disassembled cable, and which can be recycled, for example, can be recycled into an original semi-conductive tape, and which does not contain a halogen element. An object of the present invention is to provide a tape and a recyclable power cable using the tape and having more reusable members than before.

[0011]

Means for Solving the Problems and Effects of the Invention To solve the above-mentioned problems, a semiconductive tape for a power cable according to the present invention comprises a soft thermoplastic resin containing no halogen element, a conductivity imparting agent, and a release agent. Sheeting a thermoplastic and semiconductive compound containing a property imparting agent,
It is characterized by being formed by cutting.

In the semiconductive tape for an electric power cable according to the present invention, the above components such as the soft thermoplastic resin, the conductivity imparting agent and the release imparting agent are melted by heating using a Banbury mixer, an open roll or the like. The thermoplastic and semiconductive compound produced by kneading may be sheeted to a predetermined thickness using a calender roll or the like, and then cut and manufactured.

The above-mentioned semiconductive tape for a power cable contains a release-imparting agent, and it goes without saying that the above-mentioned insulating layer made of cross-linked polyethylene, poly- PVC jacket,
Or, recently, it has good peeling properties for various resins such as polyethylene jacket, which is attracting attention as a jacket that can be recycled and reused. Even when melted, they can be easily and cleanly separated from these members. Therefore, the above-mentioned semiconductive tape for power cables can be easily recovered from the disassembled cable, and since it itself has thermoplasticity, after recovery, processing such as reshaping is easy, and the original semiconductive tape can be reproduced. Such recycling is possible, and it is possible to effectively use resources.

Further, since the above-mentioned semiconductive tape for power cables does not contain a halogen element, even if it is incinerated in an incinerator after being regenerated and reused a plurality of times, for example, it does not damage the furnace and generates dioxins. It is also environmentally friendly without any risk of harm. Furthermore, the thickness of the inner and outer semiconductive layers formed using the above-described semiconductive tape for power cables is set to be relatively large in order to continuously form a layer having a smooth surface without interruption. Since the thickness can be reduced as compared with the extruded semiconductive layer that must be formed, the outer diameter of the entire power cable can be reduced, and the cost of the power cable can be reduced.

In addition, since the power cable of the present invention has a semiconductive layer formed by the above-described semiconductive tape for a power cable of the present invention, the number of reusable members is increased as compared to before, and the power cable is excellent in recyclability. It will be.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. First, the semiconductive tape for a power cable of the present invention will be described. The power cable semiconductive tape of the present invention is a soft thermoplastic resin containing no halogen element as described above,
It is formed by sheeting and cutting a thermoplastic and semiconductive compound containing a conductivity imparting agent and a release imparting agent.

Among these, examples of the soft thermoplastic resin include various soft thermoplastic resins not containing a halogen element. In particular, copolymers of ethylene and other components, for example, ethylene-vinyl acetate copolymer ( EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-acrylic acid copolymer (EAA) and the like are preferable, and among them, EVA and EEA are particularly preferably used.
Such a soft thermoplastic resin may be used alone or in combination of two or more.

In addition, an olefin resin such as low-density polyethylene, high-density polyethylene, linear polyethylene, or polypropylene may be added to the soft thermoplastic resin, particularly in consideration of its economy. When the olefin resin is added, the amount of the olefin resin is determined by the amount of the soft thermoplastic resin 1
It is preferably 50 parts by weight or less based on 00 parts by weight.

If the amount of the olefin-based resin exceeds this range, the semiconductivity and peelability of the tape may be reduced, or sheeting may not be easily performed when manufacturing the tape. Note that the addition amount of the olefin-based resin, while reducing the semiconductivity and peelability of the tape, or more reliably preventing the occurrence of the phenomenon that the sheeting becomes difficult when producing the tape, ,
In consideration of improving the economic effect by adding the olefin-based resin, it is particularly preferable to be about 10 to 40 parts by weight within the above range.

When EVA is used as the soft thermoplastic resin, a so-called acetic acid catcher such as magnesium oxide or calcium carbonate is preferably added because a long-term heating may cause a deacetic acid reaction. . The addition amount of the acetic acid catcher is 1 to 3 with respect to 100 parts by weight of EVA as a soft thermoplastic resin.
It is preferably about 0 parts by weight.

If the amount of the acetic acid catcher is less than the above range, the above-mentioned effects due to the addition of the acetic acid catcher cannot be sufficiently obtained. Peelability may be reduced, or sheeting at the time of manufacturing the tape may not be easy. To give the tape semi-conductivity,
Examples of the conductivity-imparting agent added to the soft thermoplastic resin include various conductive substances.
Acetylene black classified by its manufacturing method,
Carbon black such as furnace black or carbon-based conductive material such as conductive graphite is suitably used as the conductivity-imparting agent.

It is preferable that the added amount of the conductivity-imparting agent is about 30 to 150 parts by weight based on 100 parts by weight of the soft thermoplastic resin. If the amount of the conductivity-imparting agent is less than this range, the tape may not be able to impart semiconductivity of 1 × 10 ⁷ Ω · cm or less in the thickness direction, which is required for the shielding layer of the power cable. On the other hand, if it exceeds this range, there is a possibility that the compound cannot be sheeted neatly using the above-mentioned open roll, calendar roll and the like.

In consideration of the above-described effect of imparting semiconductivity and maintaining good sheeting properties, the amount of the conductivity-imparting agent to be added is preferably within a range of 50 to 50%.
It is preferably about 100 parts by weight. Peelable to tape, that is, when wound on a conductor or insulator layer and melted by heat during power cable production, it does not adhere to conductors, metal shielding layers, insulator layers, etc. Release agents that are added to provide a function that can be easily and cleanly peeled when connecting or disassembling a cable include, for example, silicone oil, silicone resin, polyester-modified silicone resin, acrylic-modified silicone resin,
And fluorine rubber.

The amount of the release agent is preferably about 0.1 to 10 parts by weight based on 100 parts by weight of the soft thermoplastic resin. If the amount of the release agent added is less than this range, sufficient release properties from the conductor, the metal shielding layer, the insulator layer, and the like described above cannot be obtained. There is a possibility that it may not be able to be peeled off by firmly adhering to these members. Conversely, if it exceeds this range, it is not easy to disperse homogeneously in the soft thermoplastic resin, so further improvement in peelability is expected. Not only is it impossible, but it can be economically disadvantageous.

The amount of the peeling agent to be added is within the above range, especially about 1 to 7 parts by weight, in view of the fact that the tape peeling effect can be effectively imparted by adding as little as possible. Is preferred. Short fibers of synthetic fibers or glass fibers may be added to the compound forming the semiconductive tape for power cables of the present invention.

The short fibers have the effect of withstanding the tension generated when the semiconductive tape is wound on a conductor or an insulator layer and preventing the semiconductive tape from shrinking. That is, as described later, the 5% modulus value of the semiconductive tape in a tensile test can be improved. As synthetic fibers forming short fibers, for example, polyester fibers, nylon fibers, and acrylic fibers are preferably used.

The fiber length of the short fibers is preferably about 1 to 50 mm in consideration of preventing the tape surface from becoming uneven and more reliably preventing the tape from shrinking. More preferably, it is about 5 to 20 mm. When short fibers are added, the amount
It is preferably 10 parts by weight or less based on 100 parts by weight of the soft thermoplastic resin.

If the amount of the short fibers exceeds this range, the surface of the tape may be uneven.
In consideration of more reliably preventing the tape from shrinking while preventing the tape surface from becoming uneven, the amount of the short fiber to be added is preferably within the above range.
It is preferably about 5 parts by weight.

In the compound for forming the semiconductive tape for a power cable of the present invention, various conventionally known additives such as an antioxidant and a processing aid are added in addition to the above-mentioned components. You may. In order to produce a semiconductive tape for a power cable of the present invention containing the above components, first, these components are melted and kneaded using, for example, a Banbury mixer, an open roll, a kneading type extruder, and the like. Make a thermoplastic and semi-conductive compound.

The compound is formed in the shape of a block, a sheet, a long string, or the like, and may be used as it is in the next step, or may be cut into chips having a predetermined size in some cases. In this state, it may be used for the next step. Next, the semiconductive compounds formed into various shapes as described above are sheeted to a predetermined thickness using, for example, a T-die extruder, an inflation extruder, a calendar roll, and the like, and then, using a slit machine or the like. By cutting to a predetermined width, the semiconductive tape for a power cable of the present invention is manufactured.

The thickness of the thus produced semiconductive tape for a power cable of the present invention is about 0.03 to 1.8 m.
m is preferable. If the thickness of the semiconductive tape is less than this range, the semiconductive tape may not be able to withstand the tension when wound on a conductor or an insulator layer, and the semiconductive tape may shrink in width or break. Yes, conversely, when the above range is exceeded, the thickness of the inner and outer semiconductive layers is reduced, the outer diameter of the entire power cable is reduced, and the cost of the power cable is reduced. However, the advantage of using the semiconductive tape may not be sufficiently exhibited.

The thickness of the semiconductive tape should be within the above range, especially in consideration of the balance between the above-mentioned properties, and should be within the range of 0.1 to 0.5.
It is preferably about 1 to 1.0 mm. Further, the semiconductive tape for a power cable according to the present invention is manufactured according to Japanese Industrial Standard JIS.
The 5% modulus value when subjected to a tensile test according to the measurement method described in K7113 is preferably 0.2 kg / mm ² or more.

If the 5% modulus value of the semiconductive tape is less than this range, the semiconductive tape may not be able to withstand the tension when wound on a conductor or an insulator layer, and may have a reduced width or This is because there is a risk of breaking.
The 5% modulus value is preferably at least 0.25 kg / mm ² within the above range, in order to more reliably prevent the width and breakage of the semiconductive tape.

The upper limit of the 5% modulus value is not particularly limited. However, considering the ease of winding when the semiconductive tape is wound on a conductor or an insulator layer, the 5% modulus value is not limited. , Especially within the above range.
It is preferably 0 kg / mm ² or less. In order to increase the 5% modulus value within the above preferred range, the short fibers may be added as described above, and the amount added may be adjusted within the above preferred range.

Next, the power cable of the present invention will be described. The power cable of the present invention can have the same configuration as the conventional one except that a semiconductive layer as a shielding layer is formed by the semiconductive tape of the present invention. For example, as shown in FIG. 1, the outer periphery of a conductor 11 formed by a plurality of soft copper stranded wires is formed by an inner semiconductive layer 12, an insulating layer 13 made of crosslinked polyethylene, an outer semiconductive layer 14, and a copper tape. The power cable of the present invention is configured by sequentially covering with a metal shielding layer 15 provided and a jacket 16 made of a synthetic resin such as polyvinyl chloride or cross-linked polyethylene.

In the present invention, the inner semiconductive layer 12 of the above layers is formed by winding the semiconductive tape of the present invention on the conductor 11, or the inner semiconductive layer 1
4 is formed by winding the semiconductive tape of the present invention on the insulator layer 13 or both, but the recyclability is increased by increasing the number of reusable members. In consideration of the object of the present invention to improve the thickness, both of the semiconductive layers 12 and 14 are preferably formed by winding the semiconductive tape of the present invention.

The members other than the two semiconductive layers 12 and 14 can be formed in the same manner as in the prior art. That is, conductor 1
1 is formed of a plurality of annealed copper wires as described above.
The insulator layer 13 is formed by extruding a cross-linkable polyethylene compound so as to cover the conductor 11, and then immediately heating the compound to a high temperature to cross-link the resin. The metal shielding layer 15 is formed by winding a copper tape as described above. Further, the jacket 16
After the above synthetic resin is extruded so as to cover the metal shielding layer 15, in the case of crosslinked polyethylene, it is formed by immediately heating to a high temperature to crosslink the resin.

[0038]

The present invention will be described below based on examples and comparative examples. Example 1 100 parts by weight of an ethylene-ethyl acrylate copolymer (EEA, ethyl acrylate content 9%, melt flow rate 5 dg / min) as a soft thermoplastic resin, and 70 parts by weight of acetylene black as a conductivity-imparting agent Part and a silicone oil (viscosity 100,000 c) as a release agent
St) 5 parts by weight, 5 parts by weight of magnesium oxide as an acetic acid catcher, and stearic acid 1 as a processing aid
Parts by weight and 1 part by weight of an antioxidant (trade name: Irganox 1010, manufactured by Ciba Geigy) are kneaded with a Banbury mixer, and then about 5 m thick from an open roll.
m sheet.

Next, the sheet was sheeted to a thickness of 0.2 mm using a calender roll,
mm to produce a semiconductive tape for a power cable. Example 2 In the same manner as in Example 1 except that 100 parts by weight of an ethylene-vinyl acetate copolymer (EVA, vinyl acetate content 28%, melt flow rate 1.0 dg / min) was used as a soft thermoplastic resin. Manufactured a semiconductive tape for power cables.

Example 3 The same as Example 2 except that 70 parts by weight of furnace black was used as a conductivity-imparting agent and 3 parts by weight of polyester short fiber (3.0 denier, 9.5 mm in length) was added. Thus, a semiconductive tape for a power cable was manufactured.

Comparative Example 1 A semiconductive tape for a power cable was manufactured in the same manner as in Example 1 except that silicone oil as a peeling agent was not added. The following tests were performed on the semiconductive tapes for power cables manufactured in the above Examples and Comparative Examples, and the characteristics were evaluated.

Tensile test According to the measuring method described in Japanese Industrial Standard JIS K7113, the breaking strength [kgf / mm ² ], 5% when the semiconductive tape for power cable of each of Examples and Comparative Examples was subjected to a tensile test.
The modulus value [kgf / mm ² ] and the elongation at break [%] were recorded.

Measurement of Volume Resistivity The volume resistivity [Ω] in the thickness direction of the semiconductive tape for the power cable of each of Examples and Comparative Examples was measured according to the method of JCS No. 311B specified by the Japan Electric Wire and Cable Association. .Cm]. Table 1 shows the above results.

[0044]

[Table 1]

Further, the following peeling test was conducted in order to evaluate the peeling properties of the semiconductive tapes for power cables of the above Examples and Comparative Examples in relation to the extrusion temperature of the polyethylene compound for covering. Peelability test Polyethylene sheet (dimensions 5) as a model of the insulator layer
0 mm × 50 mm), a semiconductive tape for a power cable of any of Examples and Comparative Examples, and a copper tape as a model of a metal shielding layer were laminated on a glass plate in this order.

Next, this laminate was placed in an oven set to the temperature shown in Table 2 below, and immediately placed on a Teflon liner (a sheet in which both surfaces of a glass cloth were coated with Teflon). Then, in the same oven, a polyethylene sheet (size 55 mm × 55 m) as a model of the polyethylene compound for the jacket, which was heated to the set temperature of the oven.
m) was overturned together with the Teflon liner to cover the laminate, and further, a glass plate and a load of 5 kg were placed on the laminate and heated in an oven for 10 minutes. Allowed to cool to room temperature.

The peelability of the semiconductive tape for a power cable when the laminated body integrated by heating was peeled off by hand was evaluated according to the following criteria. ：: Peeling was easy and clean without remaining on the other side. Very good peelability. ：: Peeling was slightly heavy, but could be peeled cleanly without remaining on the other side. Good peelability.

Δ: The tape was torn at the time of peeling, and a part thereof remained on the other side. Slightly poor peelability. X: No peeling was possible at all. Poor peelability. Table 2 shows the results.

[0049]

[Table 2]

From the results shown in Tables 1 and 2, the semiconductive tape of Comparative Example 1 containing no release agent had a low extruding temperature of 160 ° C. at the time of manufacturing the cable. You will not be able to remove it at all,
It was found that all of the semiconductive tapes of Examples 1 to 3 could be peeled off, although the degree of the composition varied depending on the composition.
In particular, the semiconductive tapes of Examples 2 and 3 have a jacket extrusion temperature as high as 220 ° C. during cable production,
It was confirmed that the film could be easily and cleanly peeled off from the insulator layer. Note that the semiconductive tapes of Examples and Comparative Examples could be easily and cleanly peeled off from the copper tape.

Next, in order to examine the reproducibility of the semiconductive tapes for power cables of Examples 1 to 3, and the presence or absence of deterioration of characteristics after the reproduction, the following reproduction test was performed. Regeneration test The semiconductive tape for power cable of each example was tested at 140 ° C.
Was heat-treated in an oven for 60 days, and then kneaded again with a Banbury mixer. Next, the re-kneaded material was pulled out from an open roll as a sheet having a thickness of about 5 mm, further sheeted with a calender roll to a thickness of 0.2 mm, and cut into a width of 85 mm to regenerate a semiconductive tape for a power cable.

The regenerated semiconductive tape for power cables was subjected to the tensile test and the measurement of the volume resistivity to evaluate its characteristics. Table 3 shows the results.

[0053]

[Table 3]

From the results shown in Table 3, it was confirmed that all of the regenerated semiconductive tapes of the examples maintained sufficient performance as the outer semiconductive layer of the power cable and could be reused. . When the peeling test was performed on the regenerated semiconductive tapes of the respective examples, the same good results as those before the reproduction were obtained for all the tapes.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a general layer configuration of a power cable including the power cable of the present invention.

[Explanation of symbols]

 12 Internal semiconductive layer 14 External semiconductive layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 27/12 C08L 27/12 83/04 83/04 83/10 83/10 H01B 9/02 H01B 9 / 02 B (72) Inventor Kazu Hagiwara 1820 Harajuku, Shingu-cho, Kasuya-gun, Fukuoka Prefecture Inside Shingu Plant of Fukuoka Cross Industry Co., Ltd. (72) Takashi Tanaka 1-3-1 Shimaya Konohana-ku, Osaka Sumitomo Electric Industries Inside the Osaka Works (72) Inventor Kazuru Tokumaru 1-3-1 Shimaya, Konohana-ku, Osaka-shi F-term in the Osaka Works, Sumitomo Electric Industries, Ltd. DL007 FA043 FA047 FD013 FD017 FD030 FD116 FD202 GQ01 GQ02 5G301 DA18 DA34 DA42 DA43 DA45 DA60 DD04

Claims (8)

[Claims] Claims: 1. Sheeting a thermoplastic and semiconductive compound containing a halogen-free soft thermoplastic resin, a conductivity-imparting agent, and a release-imparting agent,
A semiconductive tape for a power cable, which is formed by cutting. 2. The semiconductive material according to claim 1, wherein the thermoplastic resin is at least one selected from the group consisting of an ethylene-vinyl acetate copolymer and an ethylene-ethyl acrylate copolymer. tape. 3. The semiconductive tape according to claim 1, wherein the conductivity imparting agent is at least one selected from the group consisting of acetylene black, furnace black, and conductive graphite. 4. The power cable according to claim 1, wherein the release agent is at least one selected from the group consisting of silicone oil, silicone resin, polyester-modified silicone resin, acryl-modified silicone resin, and fluororubber. Semi-conductive tape. 5. The semi-conductive tape for an electric power cable according to claim 1, which contains a synthetic fiber or a glass fiber short fiber. 6. The semiconductive tape for a power cable according to claim 1, which has a thickness of 0.03 to 1.8 mm. 7. A 5% modulus value in a tensile test of 0.5.
2 kg / mm ² or more in a claim 1 to the power semi-conductive tape cable according to any one of the 6. 8. A power cable, wherein a semiconductive layer as a shielding layer is formed by the power cable semiconductive tape according to any one of claims 1 to 7.