JP2004087469A - Method for disassembling cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily separate a sheath and a water-barrier layer when a cable with the water-barrier layer adhering to the sheath is disassembled. <P>SOLUTION: A conductor 1 is pulled out of the cable after the cable is dismounted, and the part except the conductor 1 is cut into a suitable size and shape. The portion of the sheath 7 (portion where the water-barrier layer 6 is adhered to the sheath with a polyolefin based adhesive or the like) of the thus broken-up cable is performed with wet and heat treatment. The wet and heat treatment is performed, for example, in a state that a specimen is exposed to a high_temperature (≥60°C) and a wet (10 to 100%) environment. Preferably, the portion of the sheath 7 of the broken-up cable is performed with wet and heat treatment by being immersed in hot water. <P>COPYRIGHT: (C)2004,JPO

Description

【００２１】
表１に示すように、９０℃の温水に２４時間浸漬した後では、作業性は良好で剥離力も最も小さいのに対し、従来方法である９０℃湿度８％雰囲気中２４時間加熱後のものでは作業性が悪く、剥離力も大きくなっており、１２０℃雰囲気中２気圧３時間加熱後のものでは作業性は良いが、剥離力は大きくなっている。また、分離後のシースの状態も実施例の９０℃の温水に２４時間浸漬したものがもっとも良好となっている。
【００２２】
【発明の効果】
以上説明したように、本発明のケーブルの解体方法によれば、遮水層が接着されたシースを湿熱処理することにより、容易にシースと遮水層を分離することができる。特に温水に浸漬した後では温水から取り出して放置し、室温程度の温度になった後でも、シースと遮水層の接着力は低下した状態が維持され効果が大きい。また、分離後のシースには接着剤などが残らず、洗浄・乾燥すれば再生材料として使用することが可能である。
【図面の簡単な説明】
【図１】遮水層を用いたケーブルの断面図。
【符号の説明】
１　導体
２　内部半導電層
３　絶縁体
４　外部半導電層
５　金属遮蔽層
６　遮水層
７　シース[0001]
[Industrial applications]
The present invention relates to a method for disassembling a cable having a water impermeable layer.
[0002]
[Prior art]
For example, in a power cable, an inner semiconductive layer, an insulator made of cross-linked polyethylene, an outer semiconductive layer, and a sheath made of polyvinyl chloride or polyethylene are sequentially coated on a conductor, but the sheath penetrates from the outside. In order to block moisture, a water-impervious layer in which a polyethylene tape or the like is laminated on one or both sides of a metal foil such as lead or aluminum is provided between the outer semiconductive layer and the sheath.
[0003]
By the way, in recent years, harmful substances such as lead compounds and chlorine gas have not been eluted or generated during the disposal treatment of landfills and incineration of electric wires and cables, and environmental considerations such as easy recycling after disassembly. Is required. Regarding the material of the water-blocking layer, as with other members of electric wires and cables, lead-free and recyclable properties are being studied, and the use of aluminum from lead, which has been conventionally used, is being promoted.
[0004]
The water barrier layer is generally bonded to the cable sheath with a polyolefin adhesive, and it is difficult to separate the cable once bonded. At present, the layers are landfilled as industrial waste with the layers adhered. It is generally said that the service life of CV cables is about 30 years, and since water-impermeable layers have been used for CV cables, it will soon be 20 years later. Cables have been removed and their disposal has increased, and many are expected to be lead-based barriers.
[0005]
Conventionally, in order to separate the sheath and the impermeable layer, a method of heating to about 100 ° C. to 150 ° C. to dissolve the adhesive and then separate, or a method of separating by pressurizing at a high temperature has been performed. (For example, see Patent Document 1).
[0006]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-113738 (paragraph numbers “0012” to “0017”, FIG. 1)
[0007]
[Problems to be solved by the invention]
However, in the method of separating the sheath and the impermeable layer as described above, there is a problem in that the adhesive is cooled again while being left after heating and solidifies again, making separation difficult. In addition, since the adhesive of the water-impervious layer remains on the sheath after separation, there has been a problem that when the sheath is regenerated, mechanical properties, water absorption, and workability deteriorate.
[0008]
The present invention has been made in order to solve the above problems, and has an object to provide a method for easily separating a sheath and a water impermeable layer when a cable having a water impermeable layer adhered to a sheath is disassembled. I do.
[0009]
[Means for Solving the Problems]
The present inventors have studied a method for solving the above-described problem, and found that the sheath and the water-impermeable layer can be easily separated by performing a wet heat treatment on the sheath portion where the water-impermeable layer is bonded, This has led to the present invention.
[0010]
That is, in order to solve the above-mentioned problem, a method for disassembling a cable according to claim 1 is a method for disassembling a cable in which a water-impervious layer coated on a conductor and a sheath are bonded with an adhesive. When separating the impermeable layer from the water, the sheath and the impermeable layer are separated by wet heat treatment.
[0011]
According to a second aspect of the present invention, in the method for disassembling a cable according to the first aspect, the wet heat treatment is performed in an environment having a humidity of 10 to 100%.
[0012]
According to a third aspect of the present invention, in the method for disassembling a cable according to the first or second aspect, the wet heat treatment is immersed in warm water.
[0013]
According to a fourth aspect of the present invention, in the method for disassembling a cable according to any one of the first to third aspects, the temperature range of the wet heat treatment is 60 ° C. or more.
[0014]
According to a fifth aspect of the present invention, in the method for disassembling a cable according to any one of the first to fourth aspects, the adhesive is a polyolefin-based adhesive or a polyester-based adhesive.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described. FIG. 1 shows a cross section of a power cable using a water barrier layer. The conductor 1, the inner semiconductive layer 2, the insulator 3, the outer semiconductive layer 4, the metal shielding layer 5, the water shielding layer 6, and the sheath 7 are shown in order from the center.
[0016]
After removing such a cable, the conductor is pulled out and disassembled, and the portion other than the conductor is cut into an appropriate size and shape. According to the method for separating the water-impervious layer of the present invention, the sheath and the water-impervious layer can be easily separated by performing the wet heat treatment on the sheath portion of the thus dismantled cable where the water-impervious layer is adhered. it can. Here, the wet heat treatment refers to a treatment in a state where the sample is exposed to a high-temperature humidity environment and a treatment in a state where the sample is immersed in warm water. When the sample is exposed in a high-temperature humidity environment, water vapor may be sprayed on the sample at a high temperature. The cable disassembly method of the present invention has a great effect, particularly when immersed in warm water, as described later. The temperature range for the wet heat treatment is preferably 60 ° C. or higher, and at a temperature lower than 60 ° C., the separation effect is reduced.
[0017]
Although the water quality is not particularly limited, seawater, surfactant water, acidic water, alkaline water and the like can be used in addition to general tap water. When the sheath is made of polyvinyl chloride, water quality containing hydrochloric acid is effective.
[0018]
In this way, after being immersed in warm water, it is taken out of the warm water and allowed to stand, and even after reaching a temperature of about room temperature, the state of adhesion between the sheath and the impermeable layer is maintained, and the sheath and the impermeable layer are easily immersed. The layers can be separated. In addition, no adhesive or the like remains in the sheath after separation, and the properties of the recycled material hardly deteriorate when washed and dried.
[0019]
【Example】
Using a polyvinyl chloride sheath with a water-blocking layer of a 77 kV 80 mm2 CV cable, and using a test piece having a length of 15 cm obtained by dividing the sheath to which the water-blocking layer was attached vertically into a semicircle under the conditions shown in Table 1, The workability when separating the aqueous layer, the peeling force, and the state of the sheath after separation were evaluated. The water-impervious layer is a tape made by laminating 0.5 mm thick polyethylene terephthalate as a reinforcing layer on one side of a 0.5 mm thick lead foil and laminating a 0.1 mm thick semiconductive resin on the other side. One having a polyethylene terephthalate laminate surface side thermally fused to the sheath with a system hot melt type adhesive and one having a polyethylene terephthalate laminate surface side thermally fused to the sheath with a polyester adhesive were used. The evaluation was performed by the following method.
"Workability": Ease of peeling when the water-impermeable layer was peeled off for an appropriate length was evaluated.
"Peeling force": The water-impervious material peeled off from the test piece for an appropriate length was set on the lower grip part of the tensile tester and the other part was set on the upper grip, and the peeling force was measured at an angle of 180 ° and a peeling speed of 100 mm / min. did.
“State of the sheath after separation”: The state of the adhesive remaining on the sheath surface after the separation of the impermeable layer was visually evaluated.
[0020]
[Table 1]

[0021]
As shown in Table 1, after immersion in 90 ° C. warm water for 24 hours, the workability is good and the peeling force is the smallest, whereas the conventional method after heating for 24 hours in an atmosphere of 90 ° C. and 8% humidity is used. The workability is poor and the peeling force is large. The workability after heating in a 120 ° C. atmosphere at 2 atm for 3 hours is good, but the peeling force is large. Also, the state of the sheath after the separation is best when immersed in warm water of 90 ° C. for 24 hours in the example.
[0022]
【The invention's effect】
As described above, according to the cable disassembly method of the present invention, the sheath and the water impermeable layer can be easily separated by performing the wet heat treatment on the sheath to which the water impermeable layer is adhered. In particular, after being immersed in warm water, it is taken out of the warm water and allowed to stand, and even after reaching a temperature of about room temperature, the state in which the adhesive strength between the sheath and the water impermeable layer is reduced is maintained and the effect is large. In addition, no adhesive or the like remains on the sheath after separation, and it can be used as a recycled material if washed and dried.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a cable using a water impermeable layer.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 conductor 2 inner semiconductive layer 3 insulator 4 outer semiconductive layer 5 metal shielding layer 6 water shielding layer 7 sheath

Claims (5)

In the method of disassembling a cable in which a water-impervious layer and a sheath covered on a conductor are adhered with an adhesive, when the water-impervious layer is separated from the sheath, the sheath and the water-impervious layer are subjected to wet heat treatment. A method for dismantling a cable, comprising separating the cable. The cable disassembly method according to claim 1, wherein the wet heat treatment is performed in an environment having a humidity of 10 to 100%. The method according to claim 1, wherein the wet heat treatment is performed by immersing the cable in warm water. The method for disassembling a cable according to any one of claims 1 to 3, wherein a temperature range of the wet heat treatment is 60 ° C or more. The method according to any one of claims 1 to 4, wherein the adhesive is a polyolefin-based adhesive or a polyester-based adhesive.

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