JPH033934Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] This invention is a rubber with excellent water resistance and chemical resistance.
It concerns plastic insulated power cables. [Prior art and its problems] Rubber or plastic insulated power cables for high voltages, in which the operating voltage reaches 6,600 V, generally have an internal semiconducting layer 2 on a conductor 1, a polyethylene cross-linked It has a basic configuration in which an insulating layer 3 made of polyethylene, ethylene propylene rubber, or butyl rubber, etc., an external semiconducting layer 4, a shielding layer 5 made of copper tape, etc., and a protective sheath 6 made of a soft vinyl chloride resin composition are provided in this order. are doing. For power cables with such a configuration,
The protective sheath is not necessarily able to completely block water penetration into the interior of the cable. Moisture that reaches the cable core will eventually diffuse into the outer semiconducting layer or insulating layer, causing so-called water trees in the insulating layer, which can cause serious problems that degrade the electrical properties such as the insulation performance of the power cable. It was becoming the cause. The inventors previously proposed that a method for effectively preventing the deterioration of the electrical properties of power cables due to such moisture infiltration is provided on the cable core of the power cables, more specifically, directly above the insulating layer or the outer semiconducting layer. ,
We have proposed a number of improved power cable configurations in which a metal-plastic laminate tape is vertically wrapped and wrapped as a water-blocking layer, and we have achieved great results. On the other hand, in addition to the above-mentioned so-called water-shielding cable on the core, in which a water-shielding layer is provided on the cable core, a metal tape laminated with plastic tape on at least one side is wrapped vertically just under the outer sheath of the cable core. A so-called metal laminate sheath cable that is integrated with a sheath.
Development of an under-sheath water-shielding cable is also progressing. In this under-sheathed water-shielding cable, the following problems arose regarding the integration of the soft vinyl chloride resin composition, which is a common sheath material, and the metal-plastic laminate tape. That is, as a means of integrating a sheath material made of a soft vinyl chloride resin composition and a laminate tape, nitrile-phenolic,
A possible method is to coat the adhesive with a soft vinyl chloride resin adhesive such as nitrile rubber or polyurethane elastomer, and to bond the two together via this adhesive layer. However, as a result of trying methods using adhesives, there were problems such as uneven adhesive application and blocking, and in the long term, the plasticizer contained in the soft PVC resin composition may bleed out to the adhesive interface. However, there was a problem in that the sheath and the laminate tape eventually peeled off due to poor adhesion. Therefore, we tried a method that does not use adhesive as another means of integrating the sheath and laminate tape. In other words, a cable is produced in which the same soft vinyl chloride resin composition as the sheath material is used as the plastic material of the metal-plastic laminate tape, and the sheath and the plastic material of the laminate tape are fused and integrated using the heat during sheath extrusion. The long-term water resistance performance was evaluated. As a result, when a soft vinyl chloride resin composition is used as the plastic material for a laminated tape, there is no problem with its initial properties (integration of the sheath and the laminated tape), but after a long period of time, the soft vinyl chloride resin composition The plasticizer in the material bleeds out to the metal tape side,
As a result, the stability of adhesion between the metal tape and the plastic material deteriorates, resulting in mutual peeling and a loss of water-blocking performance. [Structure and effects of the invention] As a result of intensive studies to solve this problem, the inventors have developed a hard vinyl chloride resin composition containing 0 to 15 phr of plasticizer as the plastic material for the laminate tape. They found that effective results could be obtained by placing this on the sheath side and heat-sealing and integrating it with the soft vinyl chloride resin composition that is the sheath material, and completed this idea. That is, this invention is a power source having a basic configuration in which an inner semiconducting layer, an insulating layer, an outer semiconducting layer, a shielding layer such as a copper tape, and a protective sheath made of a vinyl chloride resin composition are provided on a conductor in this order. In the cable, the plasticizer is used as the protective sheath.
Using a soft vinyl chloride resin composition containing 20 phr or more, on the inside of the protective sheath, a metal tape is coated with a water-blocking layer laminated with a hard vinyl chloride resin composition tape containing 0 to 15 phr of plasticizer on at least one side of the metal tape. The rubber or plastic insulated power cable is made by disposing the vinyl chloride resin composition side facing the protective sheath side, and integrating the protective sheath and the hard vinyl chloride resin composition side by heat fusion. In this invention, as mentioned above, by using a hard vinyl chloride resin composition containing 0 to 15 phr of plasticizer as the plastic material of the metal-plastic laminate tape, (i) the plastic material does not contain a plasticizer or contains no plasticizer; As a result, the bleeding of the plasticizer to the metal tape side of the plastic material is drastically reduced or almost no, and the adhesion stability between the metal tape and the plastic material in the laminate tape is significantly improved. (ii) The laminate tape itself Strength, heat resistance, impact resistance, etc. are improved.Also, by using a hard vinyl chloride resin composition as described above as the plastic material, it is possible to connect a sheath material made of a soft vinyl chloride resin composition and heat without using an adhesive layer. (iii) Even if the plasticizer bleeds from the sheath material, the plasticizer in the laminated tape's plastic material is small, so it can be absorbed without remaining at the bonding interface. Since the sheath material and the laminate tape do not peel off at the joint surface, the above-mentioned problems are solved and effective results can be obtained for cable water-shielding performance. If the plasticizer in the hard vinyl chloride resin composition in the above laminated tape exceeds 15 phr, the above
None of (i), (ii) and (iii) are satisfied and the effect of this invention cannot be obtained. Metal tape materials to be laminated with the tape made of the above hard vinyl chloride resin composition include lead,
Aluminum, copper, iron, stainless steel, brass, etc. may be used, but lead is particularly preferred because of its high corrosion resistance. Regarding the thickness structure of the laminate tape, for example, from the viewpoint of workability when vertically covering the cable core and water-blocking properties, the thickness of the metal tape is 10 to 15 μm, and the thickness of the hard vinyl chloride resin composition layer is 10 to 15 μm. A range of 100μ is preferred. In particular, if the thickness of the hard vinyl chloride resin composition layer exceeds the upper limit, cracks and the like will easily occur due to the hardness of the cable due to repeated bending. In this invention, the hard vinyl chloride resin composition is provided on at least one side of the metal tape, and the hard vinyl chloride resin composition is placed toward the protective sheath and integrated with the protective sheath by heat fusion. A similar effect can be obtained by using a tape laminated with a hard vinyl chloride resin composition on both sides. [Example] Fig. 2 is a cross-sectional view of a power cable according to an embodiment of this invention, in which 7 is a laminate tape that is a water-blocking layer, 7a is a metal tape layer of the laminate tape, and 7b is a hard chloride layer. This is a vinyl resin composition tape layer, and numerals 1 to 6 in the figure are the same as the basic structure of the conventional power cable, and are indicated by the same numerals. Each part of these basic structures, ie, the conductor, insulator layer, semiconducting layer, etc., is not particularly changed from the conventional one, and a description of these materials will be omitted. As is clear from the above explanation and the examples below, this invention uses a hard vinyl chloride resin composition with significantly less plasticizer as the plastic layer of the metal-plastic laminate tape water-blocking layer used for power cables, and By arranging the vinyl chloride resin composition layer toward the soft vinyl chloride resin composition sheath side and integrating both layers by thermal fusion, it is possible to prevent the integration of both layers due to the bleed-out of the plasticizer mentioned above. It has the effect of significantly improving instability over time and improving electrical properties, especially as a high-voltage power cable, and has extremely large industrial value. This invention will be specifically explained below with reference to Examples. Examples 1 to 3, Comparative Examples 1 to 3 6KV1×100 by the usual method according to the configuration shown in Figure 2
A mm ² (19/2.6) CV cable was manufactured using the water-blocking layer laminate tape and sheath material shown in the table below. In this case, the laminate tape was vertically wrapped around the outside of the cable core, and then the lug portion was thermocompression bonded, and the sheath was extruded thereon, and the laminate tape and sheath were fused and integrated by the heat. Then each power cable is 80℃ under 15KVAC charging.
After being immersed in hot water for one year, it was taken out and AC breakdown voltage characteristics were examined, and the moisture content in the insulator and the adhesive strength between the sheath and the laminate tape were measured, and the results are shown in the same table. In the table, hard and soft vinyl chloride resin compositions are abbreviated as hard PVC and soft PVC, respectively.

【table】

[Table] *... Shown as a percentage of the initial price.
**…Peeling between soft PVC and Pb.
＊＊＊…Peeling between the sheath and the laminated tape.
According to the above results, the example product maintains sufficient adhesion even under severe conditions, has a small amount of water intrusion into the insulator, and has a small decrease in AC breakdown value.
These characteristic values of the comparative example product were significantly reduced, and it was clear that the present invention was superior.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views of power cables of a conventional product and a product of the present invention, respectively. DESCRIPTION OF SYMBOLS 1... Conductor, 2... Inner semiconducting layer, 3... Insulator layer, 4... Outer semiconducting layer, 5... Shielding layer, 6...
...sheath, 7...laminate tape (water-blocking layer),
7a...Metal tape, 7b...Hard vinyl chloride resin composition tape.

Claims (1)

[Scope of utility model registration request] In a power cable having a basic configuration in which an inner semiconducting layer, an insulating layer, an outer semiconducting layer, a shielding layer made of copper tape, etc., and a protective sheath made of a vinyl chloride resin composition etc. are provided on a conductor in this order, the protection A flexible vinyl chloride resin composition containing 20 phr or more of a plasticizer is used as a sheath, and a metal tape is laminated with a hard vinyl chloride resin composition tape containing 0 to 15 phr of a plasticizer on at least one side of the protective sheath. A rubber or plastic insulated power cable made by disposing a water layer with its hard vinyl chloride resin composition surface facing the protective sheath side, and integrating the protective sheath and the hard vinyl chloride resin composition surface by heat fusion. .