Recycling method

Abstract

To recover a non-magnetic material without lowering recycling quality in a recycling method for separating and recovering the non-magnetic material by using the non-magnetic material to which an induction heating adhesion peeling type adhesive is stuck as a recycling raw material.SOLUTION: In the recycling method, a non-magnetic material to which an induction heating adhesion peeling type adhesive containing magnetic particles adheres is used as a recycling raw material, the non-magnetic material to which the adhesive adheres is crushed to obtain mixed crushed pieces composed of crushed pieces to which the adhesive adheres and crushed pieces to which the adhesive does not adhere, the crushed pieces to which the adhesive adheres are magnetically sorted from the mixed crushed pieces, and the crushed pieces to which the adhesive does not adhere, that is, the non-magnetic material is separated and recovered.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a recycling method for separating and recovering non-magnetic materials using non-magnetic materials to which an induction heating adhesive peeling type adhesive is attached as a recycling raw material. [Background technology]

[0002] In recent years, there has been a growing momentum to improve the recycling rate of various plastic products, metal products, etc. In particular, in the automotive industry, ELV regulations, mainly in Europe, are promoting the design of parts that are easy to dismantle and the use of recycled materials. These products are generally manufactured by joining or adhering multiple parts. To improve recycling rates, it is important to separate and disassemble each joined or adhered part and separate them by material during recycling. To ensure reliable adhesion, these parts are often bonded using adhesives with high adhesive strength or heat-sealing methods such as frame lamination. However, this presents a disadvantage from a recycling perspective, making disassembly difficult at the time of disposal, and often necessitating disposal as industrial waste. Therefore, there is a need for a bonding technology that provides strong adhesion during use but allows for easy and rapid debonding during disassembly without material degradation, and allows for the recovery of highly pure materials.

[0003] In light of this situation, proposals have been made for easy-to-dismantle adhesives that normally adhere strongly but can be debonded when triggered by heat, light, water, electricity, etc. Among these, adhesive technology that uses electromagnetic induction heating (IH) has attracted attention from the perspectives of labor-saving, resource-saving, low cost, and clean working environments. Using an adhesive technology that utilizes electromagnetic induction heating (IH), for example, an adhesive tape can be hot-melted by high-frequency electromagnetic induction to adhere an adherend to a substrate, and when peeling, the adhesive tape can be hot-melted by high-frequency electromagnetic induction to peel the adherend from the substrate. In this way, hot-melt adhesives that can be peeled using electromagnetic induction heating (IH) can be peeled by remotely heating the adhesive layer with pinpoint accuracy and in a short time using IH, so not only can the adherend and substrate be peeled without damage, but thermal damage can also be minimized, and it is expected that the adherend and substrate can be suitably recycled.

[0004] Regarding technology using an adhesive that can be bonded and peeled using electromagnetic induction heating (IH) (referred to as an "induction heating adhesive peeling adhesive"), for example, Patent Document 1 discloses a method of bonding components together by electromagnetic wave induction heating using an induction heating adhesive sheet in which conductive powder is attached to one or both sides of a plastic resin sheet.

[0005] Patent Document 2 discloses a bonding method for bonding an adherend made of a resin to another adherend made of a resin different from the resin, the method comprising the steps of: laminating the adherend, a hot-melt adhesive film for induction heating, and the adherend in this order to obtain a laminate; and heating the hot-melt adhesive film for induction heating using an induction heating device; the hot-melt adhesive film for induction heating is a hot-melt adhesive film for induction heating in which a thermoplastic resin layer made of a thermoplastic resin, a metal layer, and a thermoplastic resin layer made of a thermoplastic resin are laminated in this order; and the laminate is such that the adherend and the thermoplastic resin layer are in contact, and the adherend and the thermoplastic resin layer are in contact.

[0006] It is known that magnetic particles generate heat through induction heating. This is because magnetic particles generate heat due to hysteresis loss caused by magnetic field reversal in an alternating current magnetic field. Patent Document 3, which focuses on the electromagnetic wave absorption properties of magnetic particles, discloses a resin composite containing a thermoplastic resin and a magnetic filler, the magnetic filler having an average particle diameter of 100 nm or more but less than 1000 nm, which is used to generate heat through induction heating at a temperature rise rate of 10°C / s or more. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 10-17837 [Patent Document 2] Japanese Patent Application Publication No. 2023-137899 [Patent Document 3] Japanese Patent Application Publication No. 2023-131861 Summary of the Invention [Problem to be solved by the invention]

[0008] For example, when an adhesive that can be bonded and peeled using electromagnetic induction heating (IH) (an induction heating peeling adhesive) is used to bond a substrate to a member to be adhered to it, even if the adhesive is hot-melted by IH during peeling, the adhesive undergoes cohesive failure, leaving some of the adhesive remaining on the member to be adhered to and the substrate. Therefore, if the peeled member to be adhered or the substrate is recycled as is, the recycled product will contain adhesive and magnetic particles, which results in a problem of reduced recycling quality.

[0009] Therefore, the object of the present invention is to provide a recycling method for separately recovering non-magnetic materials using one of the components peeled off by using electromagnetic induction heating (IH) from a laminate in which non-magnetic materials are bonded using an induction heating adhesive, i.e., the non-magnetic material with the induction heating adhesive attached, as a recycling raw material, and which can recover non-magnetic materials without reducing the recycling quality. [Means for solving the problem]

[0010] In order to solve this problem, the present invention proposes the following aspects.

[0011] [1] A first aspect of the present invention is a recycling method that uses non-magnetic material to which an induction heating adhesive peeling adhesive containing magnetic particles is attached as a recycled raw material, crushes the non-magnetic material to which the adhesive is attached to form mixed crushed fragments consisting of crushed fragments to which the adhesive is attached and crushed fragments to which the adhesive is not attached, magnetically separates the crushed fragments to which the adhesive is attached from the mixed crushed fragments, and separately recovers the crushed fragments to which the adhesive is not attached, i.e., the non-magnetic material.

[0012] [2] A second aspect of the present invention is a recycling method according to the first aspect, in which a laminate is formed by bonding a component A made of a non-magnetic material and a component B made of a non-magnetic material with the induction heating adhesive, and the adhesive is heated by induction heating to separate the laminate into component A to which the adhesive is attached and component B to which the adhesive is attached, and the component A to which the adhesive is attached and / or component B to which the adhesive is attached is used as the recycled raw material.

[0013] [3] A third aspect of the present invention is the recycling method according to the first or second aspect, characterized in that the induction heating adhesive is a hot melt adhesive.

[0014] [4] A fourth aspect of the present invention is the recycling method according to any one of the first to third aspects, characterized in that the magnetic particles are ferromagnetic particles. [5] A fifth aspect of the present invention is a recycling method according to any one of the first to fourth aspects, characterized in that the magnetic particles contain at least one or more of the elements Fe, Mn, Mg, Ni and Sr as their main component. [6] A sixth aspect of the present invention is the recycling method according to any one of the first to fifth aspects, characterized in that the magnetic particles contain iron oxide as a main component. [7] A seventh aspect of the present invention is a recycling method according to any one of the first to sixth aspects, characterized in that the average primary particle diameter of the magnetic particles is 100 nm or more and less than 1000 nm.

[0015] [8] An eighth aspect of the present invention is the recycling method according to any one of the first to seventh aspects, characterized in that the non-magnetic material is a resin material. [9] A ninth aspect of the present invention is the recycling method according to any one of the first to eighth aspects, characterized in that the non-magnetic material is in the form of a sheet or film. [Effects of the Invention]

[0016] The recycling method proposed by this invention involves crushing non-magnetic materials to which an induction heating adhesive peeling type adhesive containing magnetic particles has been attached, resulting in a mixture of crushed fragments with adhesive attached and crushed fragments without adhesive attached, and then magnetically separating the crushed fragments with adhesive attached from these to separate and recover the crushed fragments without adhesive attached, i.e., non-magnetic materials.This recycling method makes it possible to prevent adhesive from being included in the recycled products, i.e., the separated and recovered non-magnetic materials, and improves the recycling quality. DETAILED DESCRIPTION OF THE INVENTION

[0017] An example of an embodiment of the present invention will be described below, but the present invention is not limited to the embodiment described below.

[0018] <Recycling method of the present invention> A recycling method according to one embodiment of the present invention (referred to as "the recycling method of the present invention") is a recycling method in which non-magnetic material to which an induction heating adhesive peeling type adhesive containing magnetic particles (also referred to as "the adhesive of the present invention") is attached is used as a recycling raw material, the non-magnetic material to which the adhesive of the present invention is attached is crushed to produce mixed crushed fragments consisting of crushed fragments to which the adhesive of the present invention is attached and crushed fragments to which the adhesive is not attached (referred to as the "crushing process"), the crushed fragments to which the adhesive of the present invention is attached are magnetically separated from the mixed crushed fragments, and the crushed fragments to which the adhesive of the present invention is not attached, i.e., the non-magnetic material, are separately recovered (referred to as the "magnetic separation process").

[0019] <Recycled materials> The non-magnetic material with the adhesive of the present invention adhered thereto, which is the recycled raw material for the recycling method of the present invention, can be obtained, for example, by heating the adhesive of the present invention using electromagnetic induction heating (IH) in a laminate having a configuration in which component A made of a non-magnetic material and component B made of a non-magnetic material are bonded together with the adhesive of the present invention, thereby separating component A with the adhesive adhered thereto from component B with the adhesive adhered thereto, and then component A and / or component B with the adhesive adhered thereto can be used as the recycled raw material, i.e., non-magnetic material with the adhesive of the present invention adhered thereto. However, the recycled raw material for the recycling method of the present invention is not limited to materials obtained in this manner.

[0020] (Adhesive of the present invention) The adhesive of the present invention, i.e., the induction heating adhesive peeling type adhesive containing magnetic particles, is an adhesive that contains magnetic particles and can be bonded and peeled using electromagnetic induction heating (IH), and it is preferable that it consists of an adhesive component, i.e., a resin component, and magnetic particles. The adhesive of the present invention can usually provide strong adhesion, but can also be easily peeled off by hot-melting using IH (induction heating).

[0021] [Adhesive ingredients] The adhesive component, i.e., the resin component, of the adhesive of the present invention is preferably a hot melt adhesive, i.e., a resin containing a hot melt resin as the main component. Here, "main component resin" means the resin with the highest mass proportion among the resins contained in the adhesive of the present invention, and can be assumed to account for 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, 95 mass% or more, or 98 mass% or more of the total mass of the resins contained in the adhesive of the present invention (100 mass%).

[0022] The hot-melt resin is not particularly limited as long as it is a thermoplastic resin, and examples thereof include polyethylene resin, polypropylene resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, polyurethane resin, styrene-acrylonitrile copolymer (AS) resin, acrylonitrile-butadiene-styrene copolymer (ABS) resin, acrylic resin, polyamide resin (nylon 6, nylon 66, etc.), polyacetal resin, polycarbonate resin, polyacetal resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyphenylene ether resin, polyetherimide resin, and fluororesin. Acrylic resin is preferred from the viewpoints of moldability, safety, and availability. Among acrylic resins, polymethyl methacrylate (PMMA) is more preferred from the viewpoints of moldability (glass transition temperature) and transparency (ease of coloring).

[0023] The glass transition temperature (Tg) of the thermoplastic resin is preferably 200° C. or lower, more preferably 150° C. or lower, from the viewpoints of safety and heat damage to other members. Furthermore, from the viewpoint of viscosity adjustment and solubility, the mass average molecular weight of the thermoplastic resin is preferably 10,000 to 500,000, and more preferably 15,000 or more or 200,000 or less.

[0024] [Magnetic particles] The magnetic particles of the adhesive of the present invention may be any magnetic material, and from the viewpoint of magnetic separation efficiency, a ferromagnetic material is preferred. A "ferromagnetic material" is a material that, when an external magnetic field is applied, takes on a strong magnetism in the same direction as the applied magnetic field, and retains its strong magnetism even when the external magnetic field is removed.

[0025] As the magnetic particles of the adhesive of the present invention, from the viewpoint of being a ferromagnetic material, those containing at least one or more of the elements Fe, Mn, Mg, Ni, and Sr as a main component are preferred. For example, those containing at least one or more of iron or its oxide (such as magnetite), manganese or its oxide, magnesium or its oxide, nickel or its oxide, and strontium or its oxide as a main component are preferred. Among these, from the viewpoint of heat generation by IH, iron or its oxide (such as magnetite) is preferred. The above-mentioned main component means the component with the highest mass proportion among the magnetic particles contained in the adhesive of the present invention, and can be assumed to account for 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, 95 mass% or more, or 98 mass% or more of the total mass (100 mass%) of the magnetic particles contained in the adhesive of the present invention.

[0026] The magnetic particles may have any shape. For example, they may be spherical, hexahedral, octahedral, or acicular. Among these, from the viewpoint of heat generation by IH, hexahedral or octahedral shapes are preferred.

[0027] The magnetic particles preferably have an average primary particle diameter of 100 nm or more and less than 1000 nm. When magnetic particles are blended into an adhesive component, such as a thermoplastic resin, magnetic particles with a large average particle size will generate more heat due to Brownian relaxation than magnetic particles with a small average particle size due to Neel relaxation. In fact, magnetic particles with an average particle size of 100 nm or more but less than 1000 nm will generate more heat than magnetic particles with an average particle size of 10 to 25 nm when blended into a thermoplastic resin and subjected to dielectric heating. Therefore, from the viewpoint of heat generation of the magnetic particles, the average primary particle diameter of the magnetic particles is preferably 100 nm or more and less than 1000 nm, and more preferably 150 nm or more, and even more preferably 200 nm or more, while from the viewpoint of moldability (magnetic particle sedimentation), it is more preferably 900 nm or less, and even more preferably 700 nm or less, and even more preferably 500 nm or less. The average primary particle diameter of the magnetic particles is determined by observing with a scanning electron microscope, extracting 30 or more observable magnetic particles, and averaging the longest diameters of these particles.

[0028] The content of magnetic particles in the adhesive of the present invention is not particularly limited. For example, it is preferable that the content of magnetic particles is 0.1% by mass or more relative to the solid content of the adhesive of the present invention (components excluding the solvent), e.g., thermoplastic resin. From the viewpoint of heat generation, it is particularly preferable that the content is 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more. On the other hand, from the viewpoint of moldability, it is preferable that the content be 90% by mass or less, even more preferably 70% by mass or less, and even more preferably 50% by mass or less.

[0029] (Non-magnetic material) The non-magnetic material in the recycled raw material of the recycling method of the present invention can be assumed to be at least one of the members bonded together using the adhesive of the present invention, as described above.

[0030] The non-magnetic material may have any shape and size, but is preferably in the form of a sheet or film from the viewpoint of ease of application of a magnetic field during induction heating.

[0031] If the non-magnetic material is too thin, a high proportion of crushed pieces will have adhesive attached to them when crushed, so a certain degree of thickness is preferable in order to increase the recycling rate. On the other hand, if the material is too thick, the distance between the coil and the adhesive will increase during induction heating, which may prevent sufficient heat generation, so this is not preferable. From this viewpoint, the thickness of the non-magnetic material is preferably 0.01 to 20 mm, more preferably 0.02 mm or more or 15 mm or less, even more preferably 0.03 mm or more or 10 mm or less, even more preferably 0.05 mm or more or 5 mm or less, and even more preferably 0.1 mm or more or 3 mm or less. The thickness of the non-magnetic material means the distance between the surface to which the adhesive of the present invention is attached and the opposite surface.

[0032] The non-magnetic material may be any material as long as it is a magnetic material, i.e., one that does not have the property of being magnetically attracted, but from the viewpoint of light weight, a resin material is preferable.

[0033] (Amount and thickness of the adhesive of the present invention) In the recycled raw material, the amount of the adhesive of the present invention adhering to the non-magnetic material, i.e., the amount of the adhesive of the present invention adhering, is 10 to 1500 g / m 2 , especially 30g / m 2 or more than 800g / m 2 Below, among them, 50g / m 2 or more than 500g / m 2 It can be assumed that: Furthermore, in recycled raw materials, the thickness of the adhesive of the present invention adhering to the non-magnetic material, i.e., the thickness of the adhesive of the present invention, can be expected to be 5 μm to 500 μm, particularly 10 μm or more or 300 μm or less, and particularly 20 μm or more or 200 μm or less.

[0034] <Crushing process> The recycled raw material, i.e., the non-magnetic material to which the adhesive of the present invention is attached, may be crushed by any means, for example, a hammer mill, a ball mill, a vibrating ball mill, a blade mill, a jet mill, a tornado mill, a mill mixer, a Henschel mixer, or the like.

[0035] Regarding the degree of crushing, i.e., the size of crushed pieces after crushing, if the crushing is too large, the proportion of crushed pieces with adhesive attached will increase, so it is preferable to crush them finely to increase the recycling rate.On the other hand, if the crushing is too fine, it is not preferable because the lead time required for processing will increase and the production volume will decrease. From this perspective, the size of the crushed pieces to be crushed is preferably a size equivalent to the area of ​​a square with each side measuring 0.1 mm to 50 mm, and more preferably a size equivalent to the area of ​​a square with each side measuring 0.2 mm to 40 mm, more preferably 0.3 mm to 30 mm, more preferably 0.5 mm to 20 mm, and even more preferably 1 mm to 10 mm. From a similar viewpoint, the size of the crushed pieces is preferably 100.2% or more and 1100% or less of the thickness of the non-magnetic material, and more preferably 100.3% or more or 400% or less, more preferably 100.5% or more or 300% or less, and even more preferably 101% or more or 200% or less. From the same viewpoint, the size of the crushed pieces is preferably 10% or more and 50,000% or less of the applied thickness of the adhesive of the present invention, and more preferably 30% or more or 30,000% or less, more preferably 50% or more or 20,000% or less, and even more preferably 100% or more or 10,000% or less.

[0036] <Magnetic sorting process> Any type of magnet may be used for magnetic separation, including, for example, a permanent magnet made of any one of ferrite magnets, ferrite rubber magnets, iron-neodymium-boron alloys, alnico alloys, and samarium-cobalt alloys, or an electromagnet. The test results of the examples described below show that if the magnetic force of the magnet used for magnetic separation is too strong, non-magnetic materials may be trapped between the crushed material and the magnet to which the adhesive of the present invention is attached, resulting in a decrease in the recovery rate of the non-magnetic materials. From this perspective, ferrite magnets, ferrite rubber magnets, etc. are particularly preferred types of magnets to be used for magnetic separation.

[0037] The magnetic separation may be carried out by manually or mechanically bringing a magnet, such as a magnet bar, close to or into contact with the mixed crushed pieces, or by using a magnetic separator, such as a drum-type magnetic separator, a magnetic filter, a permanent magnet-type suspended magnetic separator, an oil-cooled suspended magnetic separator, an air-cooled suspended magnetic separator, a magnetic pulley, a grid-type magnet, a magnetic chute, a non-ferrous metal separator (eddy current separator), a counter-pole magnetic separator, a rolling oil / washing liquid de-ironizing device, or a plate magnet.

[0038] <Explanation of terms, etc.> In the present invention, the term "film" includes the term "sheet", and the term "sheet" includes the term "film".

[0039] In the present invention, when it is written "α to β" (α and β are arbitrary numbers), unless otherwise specified, it means "not less than α and not more than β", and also means "preferably greater than α" or "preferably smaller than β". Furthermore, when it is stated that "α or more" or "α≦" (α is any number), it also means "preferably greater than α" unless otherwise specified, and when it is stated that "β or less" or "≦β" (β is any number), it also means "preferably smaller than β" unless otherwise specified. Furthermore, "X and / or Y" (X and Y are optional) means to include "X and Y" as well as "X or Y". [Example]

[0040] An example of an embodiment of the present invention will be described below, but the present invention is not limited to the embodiment described below.

[0041] <Preparation of magnetic particle-containing hot melt adhesive sheet> Propylene glycol monomethyl ether was added to an acrylic polymer (Dianal BR80 manufactured by Mitsubishi Chemical Corporation, Tg 104°C) so that the solid content was 40 mass%, and the mixture was dissolved by stirring at 70°C for 3 hours to obtain a hot melt adhesive solution. Separately, ethyl acetate was added to magnetic particles (Magnetite EPT-1000, octahedral shape, D50 280 nm, manufactured by Toda Kogyo Co., Ltd.) so that the magnetic particles were 40% by mass, and then glass beads with a diameter of 3 mm were added and stirred for 20 minutes using a paint shaker. After stirring, the glass beads were removed with a metal mesh to obtain a magnetic particle dispersion.

[0042] The magnetic particle dispersion was added to the hot melt adhesive solution so that the magnetic particles accounted for 60% by mass of the adhesive composition, and the mixture was stirred by hand for 5 minutes to obtain a magnetic particle-containing pressure-sensitive adhesive composition. The above magnetic particle-containing adhesive composition was cast onto a 75 μm thick PET film (Diafoil (registered trademark) manufactured by Mitsubishi Chemical Corporation) and dried in an oven at 100°C for 10 minutes to obtain a magnetic particle-containing hot melt adhesive sheet (sample) with a 30 μm thick adhesive layer and a total thickness of 105 μm. The average primary particle diameter of the magnetic particles in the magnetic particle-containing hot melt adhesive sheet (sample) was 300 nm.

[0043] (Average primary particle size) The adhesive sheet (sample) was cut, its cross section smoothed by ion milling, and then vapor-deposited with osmium tetroxide. The resulting sample was observed with a scanning electron microscope (Hitachi SU8220). At locations that could be determined to be magnetic particles, the longest distance was measured at 30 or more points, and the average value was taken as the average particle diameter of the primary particles. It was confirmed that the majority of the magnetic particles were dispersed and present as primary particles in the adhesive sheet (sample).

[0044] Example 1 Discarded polyethylene material (size 10 mm x 10 mm x 0.5 mm), which is a non-magnetic material, and the above-mentioned hot melt adhesive sheet containing magnetic particles were each separately crushed into pieces of approximately 1 mm to 10 mm square using a mill mixer. Note that "crushed to a size of approximately 1 mm to 10 mm square" means crushed to a minimum size of 1 mm x 1 mm x 0.5 mm to a maximum size of 10 mm x 10 mm x 0.5 mm. 50 g each of the crushed polyethylene material and the crushed magnetic particle-containing hot melt adhesive sheet was weighed out, placed in a plastic bag with a zipper, and shaken for 5 minutes to obtain a mixture of the crushed polyethylene material and the magnetic particle-containing hot melt adhesive sheet. A magnetic bar consisting of a ferrite magnet (magnet type) was brought into contact with the mixture, and the crushed magnetic particle-containing hot melt adhesive sheet was magnetically attracted to the magnet and recovered, and the crushed magnetic particle-containing hot melt adhesive sheet (recovered material) was separated from the remaining crushed polyethylene material.

[0045] [Example 2] The same procedure as in Example 1 was carried out, except that the sorting was carried out using a magnet bar made of a neodymium magnet.

[0046] [Example 3] The same procedure as in Example 1 was carried out, except that the sorting was carried out using a magnetic bar made of a ferrite rubber magnet.

[0047] [Comparative Example 1] The same procedure as in Example 1 was carried out, except that the sorting was done manually without using a magnet.

[0048] <Evaluation method> The mass of the remaining crushed polyethylene material (non-magnetic material), i.e., the recovered amount of crushed polyethylene material, was divided by the initial mass (50 g) of the polyethylene material before mixing to calculate the recovery rate (mass %) of the crushed polyethylene material, i.e., the non-magnetic material recovery rate (mass %).

[0049] [Table 1]

[0050] (Consideration) From the above examples and the test results of the present invention, it has been found that by crushing non-magnetic material to which an induction heating adhesive peeling type adhesive containing magnetic particles is attached, to produce a mixture of crushed fragments with adhesive attached and crushed fragments without adhesive attached, and then magnetically separating the crushed fragments with adhesive attached from among these, it is possible to increase the recovery rate of non-magnetic material and also to prevent adhesive from being included in the separated and recovered non-magnetic material. Furthermore, it was found that if the magnetic force of the magnet used for magnetic separation is too strong, non-magnetic materials may be trapped between the crushed material and the magnet to which the adhesive of the present invention is attached, resulting in magnetic attraction and recovery, which reduces the recovery rate of non-magnetic materials. Therefore, it was found that ferrite magnets, ferrite rubber magnets, etc. are particularly preferable for magnets used for magnetic separation, from the viewpoint of not having too strong a magnetic force.

Claims

1. The recycled raw material is a non-magnetic material to which an induction heating adhesive peeling type adhesive containing magnetic particles is attached. This recycling method is characterized by crushing the non-magnetic material with adhesive attached to produce mixed crushed fragments consisting of crushed fragments with adhesive attached and crushed fragments without adhesive attached, magnetically separating the crushed fragments with adhesive attached from the mixed crushed fragments, and separately recovering the crushed fragments without adhesive attached, i.e., the non-magnetic material.

2. 2. The recycling method according to claim 1, wherein a laminate having a configuration in which a member A made of a non-magnetic material and a member B made of a non-magnetic material are bonded together with the induction heating adhesive, the adhesive is heated by induction heating to separate the laminate into a member A to which the adhesive is attached and a member B to which the adhesive is attached, and the member A and / or the member B to which the adhesive is attached is used as the recycled raw material.

3. 3. The recycling method according to claim 1, wherein the induction heating adhesive is a hot melt adhesive.

4. 3. The recycling method according to claim 1, wherein the magnetic particles are ferromagnetic particles.

5. 3. The recycling method according to claim 1, wherein the magnetic particles contain at least one or more of the elements Fe, Mn, Mg, Ni and Sr as a main component.

6. 3. The recycling method according to claim 1, wherein the magnetic particles contain iron oxide as a main component.

7. 3. The recycling method according to claim 1, wherein the magnetic particles have an average primary particle size of 100 nm or more and less than 1000 nm.

8. 3. The recycling method according to claim 1, wherein the non-magnetic material is a resin material.

9. 3. The recycling method according to claim 1, wherein the non-magnetic material is in the form of a sheet or a film.

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