JP5095094B2 - Method for recovering metal from circuit boards for electrical and electronic equipment - Google Patents

Description

  The present invention relates to a method for recovering a useful metal material from a used circuit board for electrical and electronic equipment.

  In general, circuit boards for electric and electronic devices are formed on a substrate made of a polymer material (for example, epoxy resin) by a conductive metal material such as copper, and further by various conductive bonding materials, Various electronic components (for example, transistors, resistors, capacitors, IC chips, batteries, etc.) are attached. Furthermore, since the used circuit board for electrical and electronic equipment is removed from the equipment when the electrical equipment or the electronic equipment is disassembled, a wire harness or the like fixed with a polymer material is attached via a connector or the like. There are a lot of things in the state.

  In recent years, resource recycling technology has attracted attention from the viewpoint of protecting the global environment, and the recycling of resources is being encouraged by industry for policy reasons. Therefore, various studies have been made on recycling metal materials used for circuit boards for used electrical and electronic equipment.

  For example, for the above purpose, the circuit board for electrical and electronic equipment is heated or roasted while preventing combustion to carbonize the polymer material on the circuit board, and the metal present on the circuit board. Methods for recovering materials are known from, for example, Japanese Patent Laid-Open Nos. 06-256863, 08-71521, 09-0667460, and 11-188335.

In addition, for the same purpose, Japanese Patent Publication No. 03-2935 discloses a method of dissolving copper in a waste etching solution mainly containing cupric chloride. JP-A-9-271748 discloses a method for recovering a metal material by immersing a circuit board in an alkaline aqueous solution and swelling a resin component present in the circuit board.
Japanese Patent Laid-Open No. 06-256863 Japanese Patent Laid-Open No. 08-71521 JP 09-0667460 A Japanese Patent Laid-Open No. 11-188335 Japanese Patent Publication No. 03-2935 JP-A-9-271748

  Among these methods, when carrying out a method of heating or roasting, the circuit board to be processed is placed in a chamber that can be closed for heating or roasting, and several hundred degrees, for example, 250 to It is heated or roasted at a temperature of about 450 ° C., but the circuit board is provided with components having a sealed structure such as a capacitor and a battery, and the contents are bumped, etc. Has a problem that it can burst or explode (hereinafter referred to as an explosion phenomenon). If an explosion occurs in the chamber, it may impair the safety of workers, damage the chamber walls, or generate an explosive sound, giving noise to the environment surrounding the recycling facility, or It was accompanied by a safety problem that caused explosive sounds to give discomfort or anxiety to the surrounding residents.

  In addition, when carrying out the method of immersing the circuit board in an alkaline aqueous solution, frictional heat is generated when the circuit board is first cut in the solution to form the opening, and the frictional heat ignites, Alternatively, when components such as capacitors and batteries are mounted on the circuit board, as in the case of heating or baking, these components may cause an explosion phenomenon. It was accompanied by the same safety issues as the case.

  In addition, when the method of immersing the circuit board in an aqueous solution of acid or alkali is performed, it is necessary to neutralize the acid or alkali after that, and thus a processing facility and a processing step for the neutralization step are required. In many cases, the treatment for recycling is not profitable.

  According to the method using an electrolyte solution such as cupric chloride aqueous solution, it corresponds to the elution of only a specific kind of metal (in this case copper), so in order to recover other metal materials This is also insufficient in terms of profitability because it is necessary to combine other methods.

  In view of the above problems, the present invention aims to provide a method for recovering a useful metal material from a used circuit board for electrical and electronic equipment, which can simultaneously solve the problems of safety and profitability. To do.

  1st invention of this application is the method of collect | recovering the metal material currently fixed with the polymeric material on the circuit board for electrical and electronic equipment, Comprising: The polymeric material of the circuit board for electrical and electronic equipment is stored in an organic solvent tank. A step of swelling and / or dissolving by contacting with an organic solvent, a step of separating a polymer material from a metal material of a circuit board for electrical and electronic equipment in the organic solvent tank, and a recovery of the metal material from the organic solvent tank One feature is to include a process.

  The circuit board for electrical and electronic equipment may be a circuit board used for electrical equipment and electronic equipment used in various industries. In addition to household appliances, circuit boards for control boards for indoor and outdoor wiring, circuit boards used for vehicles such as vehicles, ships and aircraft, circuit boards related to electrical control of buildings and road facilities, various industries In the present invention, various circuit boards such as circuit boards related to electrical control of apparatus equipment used in the present invention can be targeted. Depending on the size of the organic solvent tank, it may be preferable to subdivide (for example, crush, etc.) before treatment, if necessary.

  The polymeric material may be various polymeric materials including elastomers and plastomers. The organic solvent may be a general organic compound having a liquid form. The metal material is a material used for constituting a circuit board, for example, a copper material forming a circuit pattern, various bonding materials for connecting electronic components to a circuit on the board, and a wire harness. Various metal materials such as copper, iron and aluminum used for the core wire. In particular, it is preferable to recover industrially useful or expensive metal materials such as gold, silver, indium, copper and iron in relation to the main purpose of the present invention.

  In this method, a circuit board is brought into contact with an organic solvent by immersing the circuit board in an organic solvent tank, and a polymer material or wiring or electronic component on the circuit board side is covered or fixed during the immersion and contact. It utilizes the fact that the physical strength of the polymeric material is significantly reduced by swelling and / or dissolving the polymeric material on the side being coated. In the organic solvent bath in that state, the polymer material of a certain type of circuit board for electric and electronic equipment is dissolved in the organic solvent, and the polymer material of another type of circuit board for electric and electronic equipment is dissolved in the organic solvent. Since it is brittle, it can be disintegrated relatively easily in an organic solvent.

  In the second invention of the present application, the organic solvent has an SP value difference Δ | δα−δs | between the SP value δα of the organic solvent and the SP value δs of the polymer material of 0.4 or less. It is characterized by using. According to this method, even if the substrate material and / or the covering or fixing material of the circuit board is formed of two or more polymer materials or two or more composite materials, the polymer Using the SP value of the material and the organic solvent as a clue, an organic solvent capable of effectively swelling and / or dissolving the polymer material can be selected and used. The SP (solubility parameter) value is a numerical value of the square root of cohesive energy density (CED) indicating intermolecular bonding force, and is generally used as a measure of the solubility of a polymer material. Parameter.

  The third invention of the present application is characterized in that the contact step is sequentially performed in each organic solvent tank using a plurality of organic solvent tanks individually accommodating two or more selected organic solvents. . According to this method, a circuit board in which a substrate and / or a coating or fixing is formed of two or more kinds of polymer materials or two or more kinds of composite materials is used as an organic solvent suitable for each material. By selecting and using the polymer material on the substrate side of the circuit board, the polymer material on the side covering or fixing the wiring, and the polymer material on the side covering or fixing the electronic component, etc. It can be swollen and / or dissolved by the corresponding organic solvent and disintegrated relatively easily in the organic solvent. As for the order and time of immersing two or more organic solvents in an organic solvent tank, the optimum conditions can be experimentally confirmed according to the conditions used, the type of solvent, and the like.

  The fourth invention of the present application is characterized in that a mixed solvent of two or more organic solvents is used as the organic solvent. According to this method, even when the substrate material and / or coating or fixing material of the circuit board is formed of two or more polymer materials or two or more composite materials, By preparing and using an appropriate mixed solvent for the material, the polymer material on the circuit board side, the polymer material on the side covering or fixing the wiring, and the electronic parts are covered or fixed. The polymer material on the other side can be swollen and / or dissolved by the interaction of the components of the mixed solvent, and can be disintegrated relatively easily in the organic solvent. The combination and mixing ratio of organic solvents to be used can be experimentally confirmed according to the substrate material and / or coating or fixing material on the circuit board side to be used.

  The fifth invention of the present application is characterized in that stirring is performed in an organic solvent tank containing an organic solvent. When the fifth invention is implemented in combination with any of the first to fourth inventions described above, the polymer material or wiring on the circuit board side of the circuit board in the organic solvent in the organic solvent tank according to those inventions. Alternatively, by swelling and / or dissolving the polymer material on the side covering or fixing the electronic component etc., the organic solvent is allowed to flow around the physically fragile polymer material, thereby increasing the height. Molecular materials can be disintegrated relatively easily.

  As described above, each invention of the present application covers a polymer material and wiring on the substrate side of the circuit board by bringing the circuit board into contact with the organic solvent by placing the circuit board in an organic solvent tank containing the organic solvent. Alternatively, the polymer material on the fixing side and the polymer material on the side covering or fixing the electronic component are swollen and / or dissolved in an organic solvent and disintegrated relatively easily in the organic solvent, Since the metal material used for the circuit board is recovered, safety and profitability can be solved at the same time during the recycling process, and a useful metal material can be recovered.

Typical examples of the polymer material used for the circuit board include the following materials.

On the other hand, typical examples of organic solvents effective for dissolving or swelling these polymer materials include the following organic solvents.

As an organic solvent in the organic solvent tank, an organic solvent whose absolute value Δ | δα−δs | of the SP value difference between the SP value δα of the organic solvent and the SP value δs of the polymer material is 0.4 or less is used. In view of the above, effective organic solvents for the polymer materials listed in Table 1 are as follows.
Since an organic solvent having an SP value δα in the range of 10.5 to 11.3 is useful for an epoxy resin having an SP value δs = 10.9, it is determined in Table 2 that pyridine is useful. can do.

For polyvinyl chloride having an SP value of δs = 9.7, an organic solvent having an SP value of δα in the range of 9.3 to 10.1 is useful. Therefore, in Table 2, methyl acetate is useful. It can be judged that there is.
For polyethylene having an SP value of δs = 7.9, an organic solvent having an SP value of δα in the range of 7.5 to 8.3 is useful. Therefore, in Table 2, methylcyclohexane is useful. Judgment can be made.

Example 1
A circuit board made of copper is provided on the circuit board made of epoxy resin taken out of the discarded electrical product (TV), and further, various wirings attached to the transistor, resistor, capacitor, IC chip, battery, and board are provided. The invention of this application was implemented using the circuit board (circuit board A) as it was attached. In the organic solvent tank, a mixed solvent (organic solvent A) of pyridine useful for epoxy resin, methyl acetate useful for polyvinyl chloride, and methylcyclohexane useful for polyethylene was prepared and stored.

  The organic solvent A was put to a depth of about 30 cm in a stainless steel cylindrical organic solvent tank having a diameter of 50 cm and a height of 50 cm. A cylindrical stainless steel basket (about 40 to 180 mesh) having a diameter of 45 cm and a depth of 60 cm, into which about 10 kg of the circuit board A was placed, was suspended with a wire and placed in the organic solvent tank. The organic solvent bath was kept immersed for 48 hours while stirring. After 48 hours, when the stainless steel basket was pulled up, the metal material remained in the stainless steel basket, but no polymer material residue was observed. It was air-dried at room temperature with the stainless steel basket.

(Comparative Example 1)
About 10 kg of circuit board A of the same type as that used in Example 1 was placed in a roasting chamber at about 600 ° C. in a steam atmosphere and baked for 12 hours. Dozens of explosions occurred during roasting. After 12 hours, it was removed from the roasting chamber and allowed to cool at room temperature.

(Example 2)
Prepare the same three organic solvent tanks as used in Example 1, put pyridine in the first organic solvent tank (organic solvent tank 1), and in the second organic solvent tank (organic solvent tank 2). Methyl acetate was added, and methylcyclohexane was added to the third organic solvent tank (organic solvent tank 3). About 10 kg of the same type of circuit board A as used in Example 1 is put in the same stainless steel basket used in Example 1, and immersed in the organic solvent tank 12 for 12 hours, and then pulled up to room temperature while using the stainless steel bowl. And then air-dried in the organic solvent tank 2 for 12 hours and then pulled up and then air-dried at room temperature for 2 hours, and further immersed in the organic solvent tank 3 for 12 hours and air-dried at room temperature for 2 hours. Went. Note that the organic solvent is air-dried in a closed system, and the evaporated or vaporized solvent is recovered by cooling (vacuum) and trapped, and the recovered solvent can be further recycled. Therefore, even when pyridine is used, since it is not released to the surroundings, odor and the like are not substantially a problem.

実施例２−７はいずれも、３番目の有機溶媒槽から引き上げた後のステンレス製籠の中に、種々の金属材料が残留していたが、高分子材料の残留物は認められなかった。 (Example 3-7)
The operation was repeated under the same conditions as in Example 2 except that the order of the organic solvents to be immersed was changed. That is, each immersion time was 12 hours, and the room temperature air drying time at each interval was 2 hours. Table 3 shows the order of the organic solvents for immersion, including Example 2.

In all of Examples 2-7, various metal materials remained in the stainless steel bowl after being pulled up from the third organic solvent tank, but no polymer material residue was observed.

(Comparative Example 2)
The operation was repeated under the same conditions as in Example 2 with the types and order of the organic solvents to be immersed as shown in Table 4. That is, each immersion time was 12 hours, and the room temperature air drying time at each interval was 2 hours.

○：残留物無し、×：残留物あり After each operation of Comparative Example 2-7, the residue in the stainless steel basket after being pulled out from the third organic solvent tank and air-dried at room temperature for 2 hours was visually confirmed, and the result was carried out. Table 5 summarizes the results in comparison with the results of Example 2.

○: No residue, ×: Residue

  As shown in Table 5, for Comparative Example 2 using cyclopentanone (SP value = 10.4) and Comparative Example 3 using m-cresol (SP value = 10.2), circuit board materials ( Epoxy resin) residue was observed. Both of these two examples used an organic solvent in which the absolute value of the SP value difference from the SP value (10.9) of the circuit board material (epoxy resin) was larger than 0.4 points.

  For Comparative Examples 2 and 4 using xylene (SP value = 8.8) and Comparative Example 5 using n-butyl acetate (SP value = 8.5), the electronic component coating or fixing material (polyvinyl chloride) ) Residue was observed. All of these examples used an organic solvent in which the absolute value of the SP value difference from the SP value (9.7) of the electronic component coating or fixing material (polyvinyl chloride) was larger than 0.4 points.

  For Comparative Examples 2, 4, 5 and 6 using n-hexane (SP value = 7.3) and Comparative Example 7 using n-butyl acetate (SP value = 8.5), wiring coating or fixing material Residue of (polyethylene) was observed. All of these examples used an organic solvent in which the absolute value of the SP value difference from the SP value (7.9) of the wiring coating or fixing material (polyethylene) was larger than 0.4 points.

  In contrast to these comparative examples, Example 2 remains for all polymer materials of circuit board material (epoxy resin), electronic component coating or fixing material (polyvinyl chloride) and wiring coating or fixing material (polyethylene). Things were not recognized. Therefore, the SP value difference between the SP value δα of the organic solvent and the SP value δs of the polymer material is a guideline for selecting the organic solvent for swelling and / or dissolving the polymer material of the circuit board for electrical and electronic equipment. It has been confirmed that it is effective to use those whose absolute value Δ | δα−δs |

Claims (2)

A circuit board composed of a first polymer material, an electronic component, a second polymer material that covers or fixes the electronic component, a wiring, and a third polymer material that covers or fixes the wiring A method of recovering a metal material from a circuit board for electrical and electronic equipment comprising:
Using three organic solvent tanks individually containing different organic solvents, the circuit board for electrical and electronic equipment is sequentially brought into contact with the organic solvents respectively stored in the three organic solvent tanks, and the first, second and A contact separation step in which the third polymer material is separated by swelling and / or dissolving in different organic solvent tanks;
Of the three organic solvent tanks, the first organic solvent tank is used to perform the contact separation process, and then the second organic solvent tank is used to perform the contact separation process before the first organic solvent tank is obtained from the first organic solvent tank. After the residue of the circuit board for electrical and electronic equipment is dried and the contact separation step is performed using the next organic solvent tank, the next step is performed before the contact separation process is performed using the last organic solvent tank. A drying step of drying the residue obtained from the organic solvent tank;
A recovery step of performing a catalytic separation process using the last organic solvent tank among the three organic solvent tanks and recovering a metal material in the form of a residue obtained from the last organic solvent tank. Become
The first polymer material is an epoxy resin;
The second polymeric material is polyvinyl chloride;
The third polymeric material is polyethylene;
The organic solvent that swells and / or dissolves the first polymeric material is pyridine,
The organic solvent that swells and / or dissolves the second polymeric material is methyl acetate;
A method in which the organic solvent for swelling and / or dissolving the third polymer material is methylcyclohexane . Claim 1 Symbol placement method and performing stirring in an organic solvent bath containing the organic solvent.