Method for recovering conductive wire

Abstract

To provide a method for recovering a conductive wire by which the conductive wire can easily be recovered from a covered conductor without generating toxic gas, such as corrosive gas.SOLUTION: A method for recovering a conductive wire is intended to recover the conductive wire from a covered conductor including the conductive wire and a covering material made of resin which covers the conductive wire. The method includes: swelling the covering material by immersing the covered conductor in heated oil; and separating the swelled covering material and the conductive wire. A temperature of the oil is 65°C or higher and lower than 130°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for recovering conductive wires. [Background technology]

[0002] Insulated conductors, which are conductive wires covered with a coating material, are used in automobiles, household electrical appliances (home appliances), buildings, etc. Therefore, when automobiles, home appliances, buildings, etc. are discarded, the insulated conductors are discarded as waste. Discarded insulated conductors are separated into the conductive wire and the coating material, and each is reused.

[0003] Known methods for separating a conductive wire from a coating include, for example, a method in which the resin coating is peeled off from the conductive wire by heating and carbonizing the coating (see, for example, Patent Document 1). Also known methods for separating a conductive wire from a coating include, for example, a method in which the coated conductive wire is finely cut into chips using a shearing machine, and the resin coating is peeled off from the conductive wire (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5134719 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-089358 Summary of the Invention [Problem to be solved by the invention]

[0005] The method described in Patent Document 1 has the problem that carbonized coating material adheres to the conductive wire, reducing the purity of the recovered conductive wire. Also, the thermal decomposition of the vinyl chloride resin contained in the coating material generates corrosive gases such as hydrogen chloride gas, which deteriorates the reactor and piping and makes the treatment of the corrosive gases complicated.

[0006] The method described in Patent Document 2 involves physically peeling the coating material from the conductive wire when cutting the coated conductor wire, which leaves small pieces of the coating material remaining on the recovered conductive wire, reducing the purity of the recovered conductive wire. Furthermore, to accurately separate the coating material from the conductive wire, the crusher's screen needs to be finer. As the screen mesh becomes finer, the crushing time increases, reducing processing efficiency. Furthermore, when the recovered conductive wire is used as a raw material for copper wrought products, the extremely fine particle size results in a poor melting yield.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a method for recovering conductive wires that can easily recover conductive wires from coated conductive wires without generating toxic gases such as corrosive gases. [Means for solving the problem]

[0008] The present invention has the following aspects. [1] A method for recovering a conductive wire from a coated conductive wire including a conductive wire and a resin coating material that coats the conductive wire, comprising: immersing the coated conductor in heated oil to swell the coating material; and separating the swollen covering material from the conductive wire, The method for recovering a conductive wire, wherein the temperature of the oil is 65°C or higher and lower than 130°C. [2] The conductive wire recovery method according to [1], wherein the coated conductive wire is immersed in the oil for 0.5 minutes or more and 50 minutes or less. [3] The method for recovering conductive wires according to [1] or [2], wherein the oil is at least one selected from unused oil and waste oil. [4] The method for recovering conductive wires according to any one of [1] to [3], wherein the covering material is made of polyolefin and chlorine-containing synthetic resin. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for recovering a conductive wire that can easily recover a conductive wire from a coated conductive wire without generating toxic gases such as corrosive gases. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Conductive wire recovery method] A conductive wire recovery method according to one embodiment of the present invention is a method for recovering a conductive wire from a coated conductor wire that includes a conductive wire and a resin coating material that coats the conductive wire. The conductive wire recovery method according to one embodiment of the present invention includes a step of immersing the coated conductor wire in heated oil to swell the coating material (hereinafter referred to as the "first step"), and a step of separating the swollen coating material from the conductive wire (hereinafter referred to as the "second step").

[0011] "Coated conductor" The coated conductor wire in this embodiment includes a conductive wire and a resin coating material that coats the conductive wire.

[0012] The conductive wire is not particularly limited, but examples thereof include copper wire and aluminum wire.

[0013] The material for the covering material is not particularly limited, but examples thereof include polyolefin and chlorine-containing synthetic resin. Examples of polyolefins include polyethylene and polypropylene. Examples of chlorine-containing synthetic resins include polyvinyl chloride resin, polyvinylidene chloride resin, vinyl chloride or vinylidene chloride copolymer resins such as vinyl chloride ethylene copolymer and vinyl chloride vinyl acetate copolymer, chlorinated resins such as chlorinated polyethylene, chlorinated rubber and chlorinated polyether, and blends of chlorine-containing synthetic resins with other resins.

[0014] "First step" The temperature of the oil in which the coated conductor wire is immersed is 65°C or higher but lower than 130°C, preferably 70°C or higher but lower than 125°C, and more preferably 90°C or higher but lower than 120°C. If the oil temperature is lower than the lower limit, the coating material will not swell even if the coated conductor wire is immersed in the oil, making it difficult to pull the conductive wire out of the coating material. If the oil temperature is higher than the upper limit, the coating material may thermally decompose, generating toxic gases such as corrosive gases.

[0015] The method for heating the oil is not particularly limited, but examples include a method in which a throw-in type electric heater is placed in a container containing the oil, and a method in which an electric heater is placed around a container containing the oil.

[0016] The temperature of the oil in which the coated conductor wire is immersed is preferably equal to or higher than the glass transition temperature of the coating material and lower than the melting point of the coating material. When the oil temperature is within this range, the coating material does not thermally decompose, and toxic gases such as corrosive gases are not generated, allowing the conductive wire to be easily pulled out of the coated conductor wire.

[0017] The time for which the coated conductor wire is immersed in oil is preferably 0.5 minutes to 50 minutes, more preferably 1 minute to 20 minutes, and even more preferably 3 minutes to 10 minutes. If the time for which the coated conductor wire is immersed in oil is less than the lower limit, the thermal decomposition of the coating material is insufficient. If the time for which the coated conductor wire is immersed in oil exceeds the upper limit, the coating material melts or burns, making it difficult to recover.

[0018] While the coated conductor wire is immersed in oil, the oil and the coated conductor wire may be stirred, or the oil and the coated conductor wire may be left to stand. By stirring the oil and the coated conductor wire, the oil can easily penetrate between the conductive wire and the coating, making it possible to more efficiently pull out the conductive wire from the coated conductor wire.

[0019] The ability to pull out the conductive wire from the coated conductor can be determined when the coating material swells and softens with oil, making the end of the conductive wire that is about to come loose visible.

[0020] The oil is at least one selected from the group consisting of virgin oil and waste oil, and functions as a heat transfer medium for the coating material, contributing to the swelling and softening of the coating material.

[0021] The virgin oil may be at least one selected from mineral oil, vegetable oil, and animal oil, and may be one type of oil used alone or two or more types of oil used in combination. Examples of mineral oils include lubricating oils such as turbine oil, mashine oil, spindle oil, brake oil, gasoline engine lubricating oil, and diesel engine lubricating oil, insulating oil, cutting oil, hydraulic oil, compressor oil, and fuel oil. Examples of vegetable oils include soybean oil, cottonseed oil, palm oil, safflower oil, olive oil, coconut oil, sesame oil, rapeseed oil, corn oil, sunflower oil, rice bran oil, safflower oil, tung oil, camellia oil, castor oil, linseed oil, peanut oil, cacao oil, corn oil, and kapok oil. Examples of animal fats and oils include beef tallow, lard, horse fat, mutton fat, milk fat, fish oils such as squid oil, herring oil, sardine oil, and cuttlefish oil, and whale oil.

[0022] Examples of waste oil include high-boiling, stable waste oils such as cooking oil and turbine oil.

[0023] It should be noted that the predetermined temperature can be set using any of the above oils.

[0024] "Second step" The method for separating the swollen coating material from the conductive wire is not particularly limited, but examples include a method of grasping the coating material with pliers or the like and peeling it off from the conductive wire, or a method of peeling off the coating material while wearing heat-resistant gloves.

[0025] The separated conductive wire and covering material are then collected and reused.

[0026] "Third step" The conductive wire recovery method of this embodiment may include a third step of removing the oil used in the first step from the conductive wire and the covering material. In the third step, the oil can be removed, for example, by repeatedly washing the conductive wire and the covering material with a solvent that dissolves the oil.

[0027] According to the conductive wire recovery method of this embodiment, in the first step of immersing a coated conductive wire in heated oil to swell the coating material, the oil temperature is set to 65°C or higher and lower than 130°C, which causes the coating material to swell and makes it easy to pull out the conductive wire from the coating material. This also prevents the coating material from thermally decomposing and generating toxic gases such as corrosive gases. In other words, the coating material and the conductive wire can be separated in an environmentally friendly manner.

[0028] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as set forth in the claims. [Example]

[0029] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0030] [Coated conductor wire] "Coated conductor 1" A vinyl chloride resin-coated copper wire (referred to as "PVC copper wire" in Table 1) was prepared by covering a copper wire having a diameter of 0.9 mm with a coating material made of polyvinyl chloride resin having a thickness of 0.3 mm.

[0031] "Coated conductor 2" A polyethylene-coated copper wire (referred to as "polyethylene copper wire" in Table 1) was prepared by covering a copper wire having a diameter of 0.9 mm with a coating material made of polyethylene having a thickness of 0.25 mm.

[0032] [Example 1] The coated conductor 1 was immersed in salad oil (product name: edible blend oil, manufactured by Nisshin Oillio Group, Inc.) adjusted to a temperature of 125°C for 5 minutes. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out from the coating. Furthermore, the coating was thermally decomposed and no toxic gas was generated. The results are shown in Table 1. In Table 1, cases where the copper wire could be easily pulled out from the coating were marked with an "O" and cases where the copper wire could not be easily pulled out from the coating were marked with an "X". In Table 1, cases where no toxic gas was generated were marked with an "O" and cases where toxic gas was generated were marked with an "X".

[0033] [Example 2] The coated conductor 2 was immersed in salad oil (product name: edible blend oil, manufactured by Nisshin Oillio Group, Inc.) adjusted to a temperature of 125°C for 5 minutes. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0034] [Example 3] The coated conductor 2 was immersed in waste oil (waste cooking oil) whose temperature was adjusted to 125° C. for 5 minutes. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0035] [Example 4] The coated conductor 2 was immersed in brake oil (trade name: Super Hydro 46A, manufactured by Idemitsu Kosan Co., Ltd.) whose temperature had been adjusted to 125° C. for 5 minutes. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0036] [Example 5] The coated conductor 1 was immersed in salad oil (product name: edible blend oil, manufactured by Nisshin Oillio Group, Inc.) adjusted to a temperature of 90°C for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0037] [Example 6] The coated conductor 2 was immersed in salad oil (product name: edible blend oil, manufactured by Nisshin Oillio Group, Inc.) adjusted to a temperature of 90°C for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0038] [Example 7] The coated conductor 2 was immersed in waste oil (waste cooking oil) whose temperature had been adjusted to 90° C. for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0039] [Example 8] The coated conductor 2 was immersed in Breken oil (trade name: Super Hydro 46A, manufactured by Idemitsu Kosan Co., Ltd.) whose temperature had been adjusted to 90°C for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0040] [Example 9] The coated conductor 2 was immersed in salad oil (product name: edible blend oil, manufactured by Nisshin Oillio Group, Inc.) adjusted to a temperature of 80°C for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0041] [Example 10] The coated conductor 2 was immersed in waste oil (waste cooking oil) whose temperature had been adjusted to 80° C. for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0042] [Example 11] The coated conductor 2 was immersed in brake oil (trade name: Super Hydro 46A, manufactured by Idemitsu Kosan Co., Ltd.) whose temperature had been adjusted to 80°C for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0043] [Example 12] The coated conductor 2 was immersed in salad oil (product name: edible blend oil, manufactured by Nisshin Oillio Group, Inc.) adjusted to a temperature of 70°C for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0044] [Example 13] The coated conductor 2 was immersed in waste oil (waste cooking oil) whose temperature had been adjusted to 70° C. for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0045] [Example 14] The coated conductor 2 was immersed in brake oil (trade name: Super Hydro 46A, manufactured by Idemitsu Kosan Co., Ltd.) whose temperature had been adjusted to 70°C for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could be easily pulled out of the coating. Furthermore, the coating did not thermally decompose, and no toxic gases were generated. The results are shown in Table 1.

[0046] [Comparative Example 1] The coated conductor 2 was immersed in salad oil (product name: edible blend oil, manufactured by Nisshin Oillio Group, Inc.) adjusted to a temperature of 60°C for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could not be easily pulled out from the coating. The coating thermally decomposed, generating toxic gas. The results are shown in Table 1.

[0047] Comparative Example 2 The coated conductor 2 was immersed in waste oil (waste cooking oil) whose temperature had been adjusted to 60° C. for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could not be easily pulled out from the coating. The coating thermally decomposed, generating toxic gas. The results are shown in Table 1.

[0048] Comparative Example 3 The coated conductor 2 was immersed in brake oil (trade name: Super Hydro 46A, manufactured by Idemitsu Kosan Co., Ltd.) whose temperature had been adjusted to 60°C for 1 minute. The end of the copper wire was then grasped with pliers and pulled. As a result, the copper wire could not be easily pulled out from the coating. The coating thermally decomposed, generating toxic gas. The results are shown in Table 1.

[0049] [Table 1]

[0050] These results confirmed that the copper wire could be easily separated from the coating when the oil temperature was between 65°C and 130°C. In addition, the coating did not thermally decompose and no toxic gases were generated.

Claims

1. A method for recovering a conductive wire from a coated conductive wire including a conductive wire and a resin coating material that coats the conductive wire, the method comprising: immersing the coated conductor in heated oil to swell the coating material; and separating the swollen covering material from the conductive wire, The method for recovering a conductive wire, wherein the temperature of the oil is 65°C or higher and lower than 130°C.

2. 2. The method for recovering a conductive wire according to claim 1, wherein the time for immersing the coated conductive wire in the oil is from 0.5 minutes to 50 minutes.

3. The method for recovering conductive wires according to claim 1 or 2, wherein the oil is at least one selected from unused oil and waste oil.

4. 3. The method for recovering conductive wires according to claim 1, wherein the covering material is made of polyolefin or chlorine-containing synthetic resin.

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