Method for separating laminates

Abstract

To provide a method for separating laminates that allows for finer separation between each layer of the laminate and reduces processing time. [Solution] According to the embodiment, the method for separating the laminate involves irradiating at least one of the following with laser light: a first interface between the first layer and a layer superimposed on the first layer, through which the first layer on the surface side of the laminate passes; and a second interface between the second layer and a third layer superimposed on the second layer, through which the second layer passes in addition to the first layer. When the first interface is irradiated with laser light, the adhesion between the first and second layers is destroyed, or the adhesion is destroyed, and the energy of the laser light is transmitted through the second layer to the third layer, destroying the adhesion between the second and third layers. When the second interface is irradiated with laser light, the adhesion between the second and third layers is destroyed, or the adhesion is destroyed, and the energy of the laser light is transmitted through the second layer to the first layer, destroying the adhesion between the first and second layers.

Description

Technical Field

[0001] Embodiments of the present invention relate to a method for separating laminates.

Background Art

[0002] For example, various laminates such as solar panels are desired to be recycled while maintaining the shape (state) of each layer constituting the laminate as intact as possible. To perform such recycling, for example, there is a technique for separating layers of a laminate using laser light.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a method for separating a laminate that can separate each layer of the laminate more finely and shorten the processing time.

Means for Solving the Problems

[0005] According to the embodiment, the method for separating the laminate involves irradiating at least one of the following with laser light: a first interface between the first layer and a second layer superimposed on the first layer, where the optical properties of adjacent layers in the stacking direction differ; and a second interface between the second layer and a third layer superimposed on the second layer on the opposite side from the first layer, where the laser light penetrates both the first and second layers. When the laser light is irradiated on the first interface, the adhesion between the first and second layers is destroyed, or the adhesion between the first and second layers is destroyed, and the energy of the laser light is transmitted through the second layer to the third layer, destroying the adhesion between the second and third layers. Furthermore, when laser light is shone on the second interface, it destroys the adhesion between the second layer and the third layer, or destroys the adhesion between the second layer and the third layer, and also transmits the energy of the laser light to the first layer through the second layer, destroying the adhesion between the first layer and the second layer. [Brief explanation of the drawing]

[0006] [Figure 1] A schematic diagram showing the relationship between the laminated structure of a solar panel as a laminated body according to the first embodiment and the laser light that is irradiated onto the laminated structure to break the adhesion between layers. [Figure 2] A schematic diagram showing the process of breaking the adhesion between layers of a solar panel as a laminate according to the first embodiment and removing each component. [Figure 3] A schematic diagram showing the process of breaking the adhesion between layers of the laminate according to the second embodiment and removing each component. [Figure 4] A schematic diagram showing the process of breaking the adhesion between layers of the laminate according to the third embodiment and removing each component. [Modes for carrying out the invention]

[0007] The method for separating the laminate 10 according to the embodiment will be described below with reference to the drawings.

[0008] (First Embodiment) Figure 1 shows, for example, a solar panel (photovoltaic panel) used for photovoltaic power generation as the laminate 10. The laminate 10 has a multi-layered structure. In this embodiment, a method for separating the solar panel as the laminate 10 will be described.

[0009] The solar panel as the laminate 10 in this embodiment may be a single-sided panel or a double-sided panel, but as an example, it will be a single-sided panel. The solar panel as the laminate 10 will have a first layer 12, a second layer 14, a third layer 16, a fourth layer 18, and a fifth layer 20 when viewed from the side into which sunlight is incident. In this embodiment, an example of a five-layer laminate 10 will be described, but this embodiment can be applied to laminates of three or more layers, for example.

[0010] Generally, the solar panels as a laminate 10 are arranged on a frame (not shown) made of, for example, aluminum. However, the frame is removed from the solar panels beforehand, and the laminate 10 does not include the frame. Also, the junction box (not shown) is removed from the solar panels as a laminate 10.

[0011] The first layer 12 is formed, for example, as a transparent, flat glass plate (glass layer).

[0012] The second layer 14 is, for example, a thermoplastic resin film (first thermoplastic resin layer) such as EVA (ethylene vinyl acetate copolymer). The second layer 14 is preferably formed as an adhesive layer for a thin film. The second layer 14 absorbs or transmits light depending on the wavelength of light. In this embodiment, the second layer 14 is formed to absorb laser light in the mid-infrared region, for example, but to transmit laser light in the visible light region and laser light in the near-infrared region.

[0013] The third layer 16 is preferably a flat, plate-shaped power generation element (solar cell) containing silicon, silver, or the like. The third layer 16 is formed as a solar cell layer that absorbs or transmits light depending on the wavelength of light, while exhibiting a photovoltaic effect that generates electromotive force when light strikes it. In this embodiment, the third layer 16 is formed to absorb laser light in the visible light range but transmit laser light in the mid-infrared and near-infrared light ranges, for example.

[0014] The fourth layer 18 is, for example, a thermoplastic resin film such as EVA (the second thermoplastic resin layer). The fourth layer 18 is preferably formed as an adhesive layer for a thin film. The fourth layer 18 absorbs or transmits light depending on the wavelength of light. In this embodiment, the fourth layer 18 is formed to absorb laser light in the mid-infrared region, for example, but to transmit laser light in the visible light region and laser light in the near-infrared region.

[0015] The fifth layer 20 is formed, for example, as a backsheet of a solar panel. The fifth layer 20 is made of a resin material that adheres closely to the fourth layer (second thermoplastic resin layer) and protects the third layer 16, and is formed as a backsheet layer that absorbs light according to the wavelength of light. In this embodiment, the fifth layer 20 is formed to absorb, for example, laser light in the visible light range and laser light in the near-infrared light range. On the other hand, the fifth layer 20 is preferably opaque, for example, white, so as to easily reflect light that has passed through the first layer 12, the second layer 14, the third layer 16, and the fourth layer 18, and so as to allow more light to enter the third layer (solar cell layer) 16 through the fourth layer 18.

[0016] Furthermore, the backsheet, which is the fifth layer 20, is preferably formed as a laminate of multiple layers of resin material. Since the backsheet, which is the fifth layer 20, is a single layer in terms of the unit that can be recycled, it will be described here as a single layer.

[0017] Note that adjacent layers in the stacking direction of the laminate 10 (the relationship between the first layer 12 and the second layer 14, the relationship between the second layer 14 and the third layer 16, the relationship between the third layer 16 and the fourth layer 18, and the relationship between the fourth layer 18 and the fifth layer 20) have different optical properties. In this embodiment, it is preferable that the optical properties of the second layer 14 and the fourth layer 18 are the same, but these layers 14 and 18 are not adjacent in the stacking direction. Also, if they are adjacent, it is assumed that their optical properties are the same and they are treated as a single layer.

[0018] In the solar panel as a laminate 10, for example, due to the thermoplasticity of the second layer 14, the second layer 14 is heated to bond and create a tight seal between the first layer 12 and the second layer 14, and between the second layer 14 and the third layer 16, and then cooled to ambient temperature to maintain the tight seal between these layers. Similarly, in the solar panel as a laminate 10, for example, due to the thermoplasticity of the fourth layer 18, the fourth layer 18 is heated to bond and create a tight seal between the third layer 16 and the fourth layer 18, and between the fourth layer 18 and the fifth layer 20, and then cooled to ambient temperature to maintain the tight seal between these layers. The fifth layer 20 may be formed of a thermoplastic resin material, similar to EVA, but it is preferable that its melting point be set to a higher temperature than that of the EVA in the fourth layer 18.

[0019] One example of a solar panel as a single stacked structure 10 is a size of 1m (1000mm) x 1.6m (1600mm).

[0020] In this embodiment, in order to break the adhesion between the layers of the laminate 10, a laser light output device (not shown) that oscillates (outputs) laser light with appropriate outputs of a plurality of different wavelengths is used. In this embodiment, the laser light output device can, for example, emit laser light with wavelengths in the visible light range (for example, 380 nm to 780 nm), laser light with wavelengths in the near-infrared light range (for example, 780 nm to 2500 nm (2.5 μm)), and laser light with wavelengths in the mid-infrared light range (for example, 2500 nm (2.5 μm) to 15000 nm (15 μm)) at appropriate outputs, and can scan an appropriate range at an appropriate speed with an appropriate spot diameter. In this embodiment, an example of scanning the laminate 10 with laser light will be described, but the laminate 10 may be moved, for example, along a single axis. Also, it is common for the scanning range of the laser light output device to be limited. For this reason, it is also preferable that the laser light output device and the laminate 10 are arranged such that the laser light output device and the laminate 10 are relatively moved so that the entire surface of the laminate 10 is irradiated with the laser light.

[0021] The maximum output of the laser light from the laser light output device is preferably on the order of several thousand watts. The actual output of the laser light from the laser light output device can be set as appropriate. The spot diameter is preferably, for example, on the order of 0.1 mm to several mm. The scanning speed is preferably on the order of tens of thousands of mm per second. The laser light in each wavelength range may be pulsed oscillation, but continuous oscillation is more preferable.

[0022] Note that, for example, one selected from a disk laser, a semiconductor laser, etc. is used as the device that oscillates laser light with wavelengths in the visible light range. For example, one selected from a semiconductor laser, a disk laser, a fiber laser, etc. is used as the device that oscillates laser light with wavelengths in the near-infrared light range. For example, one selected from a semiconductor laser, a fiber laser, a quantum cascade laser, etc. is used as the device that oscillates laser light with wavelengths in the mid-infrared light range.

[0023] The wavelength of the first laser beam L1 is one that passes through the first layer 12 and is absorbed by the second layer 14 (for example, mid-infrared light). Alternatively, the wavelength of the first laser beam L1 is one that passes through the first layer 12, the second layer 14, and the third layer 16 and is absorbed by the fourth layer 18 (for example, mid-infrared light).

[0024] The wavelength of the second laser beam L2 is one that passes through the first layer 12 and the second layer 14 and is absorbed by the third layer 16 (for example, visible light). Alternatively, the wavelength of the second laser beam L2 is one that passes through the first layer 12, the second layer 14, the third layer 16, and the fourth layer 18 and is absorbed by the fifth layer 20 (for example, visible light).

[0025] The wavelength of the third laser beam L3 is one that passes through the first layer 12, the second layer 14, the third layer 16, and the fourth layer 18, and is absorbed by the fifth layer 20 (for example, near-infrared light).

[0026] A separation method for breaking the adhesion between layers of the laminate 10 and separating the laminate 10 layer by layer will be explained using Figure 1.

[0027] First, the laminate 10 is placed on, for example, a suitable stand (not shown) or the like, so that laser light is irradiated from the first layer 12 side of the laminate 10.

[0028] As shown in Figure 1, for example, a laser beam (first laser beam) L1 in the mid-infrared region is preferably irradiated onto the interface (first interface) 13 between the first layer 12 and the second layer 14 from a direction perpendicular to the interface 13 between the first layer 12 and the second layer 14 and facing the first layer 12. At this time, preferably the entire interlayer space between the first layer 12 and the second layer 14 is scanned. The wavelength of the first laser beam L1 is such that it is absorbed on the second layer 14 side of the interface 13 between the first layer 12 and the second layer 14, thereby destroying the molecular structure on the second layer 14 side of the interface 13. Consequently, the adhesion of the first layer 12 to the second layer 14, that is, the interlayer adhesion between the first layer 12 and the second layer 14, is destroyed.

[0029] Preferably, a visible light laser beam (second laser beam) L2 is irradiated onto the interface (second interface) 15 between the second layer 14 and the third layer 16 from a direction perpendicular to the interface 15 between the second layer 14 and the third layer 16 and facing the first layer 12. At this time, preferably, the entire interlayer space between the second layer 14 and the third layer 16 is scanned. The second laser beam L2 is absorbed, for example, on the third layer 16 side of the interface 15 between the second layer 14 and the third layer 16, heating the surface of the third layer 16. This heat melts, for example, the second layer 14 of the thermoplastic resin material, reducing the adhesion at the interface 15 between the second layer 14 and the third layer 16. Therefore, the interlayer adhesion between the second layer 14 and the third layer 16 is destroyed.

[0030] Preferably, a laser beam (first laser beam) L1 in the mid-infrared region is irradiated onto the interface (third interface) 17 between the third layer 16 and the fourth layer 18 from a direction perpendicular to the interface 17 between the third layer 16 and the fourth layer 18 and facing the first layer 12. At this time, preferably, the entire interlayer space between the third layer 16 and the fourth layer 18 is scanned. The first laser beam L1 is absorbed on the fourth layer 18 side of the interface 17 between the third layer 16 and the fourth layer 18, destroying the molecular structure. Therefore, the adhesion of the fourth layer 18 to the third layer 16, that is, the interlayer adhesion between the third layer 16 and the fourth layer 18, is destroyed.

[0031] Preferably, a laser beam in the near-infrared region (third laser beam) L3 or a laser beam in the visible light region (second laser beam) L2 is irradiated onto the interface 19 between the fourth layer 18 and the fifth layer 20 (the fourth interface) from a direction perpendicular to the interface 19 between the fourth layer 18 and the fifth layer 20 and facing the first layer 12. At this time, preferably, the entire interlayer space between the fourth layer 18 and the fifth layer 20 is scanned. The third laser beam L3 or the second laser beam L2 is absorbed, for example, on the fifth layer 20 side of the interface 19 between the fourth layer 18 and the fifth layer 20, heating the surface of the fifth layer 20. This heat causes, for example, the thermoplastic resin material of the fifth layer 20 to melt or destroy its molecular structure, thereby reducing the adhesion at the interface 19 between the fourth layer 18 and the fifth layer 20. Therefore, the interlayer adhesion between the fourth layer 18 and the fifth layer 20 is broken.

[0032] The order in which the laser beams are irradiated may be as follows: the first interface 13 between the first layer 12 and the second layer 14, the second interface 15 between the second layer 14 and the third layer 16, the third interface 17 between the third layer 16 and the fourth layer 18, and the fourth interface 19 between the fourth layer 18 and the fifth layer 20. However, these orders can be set as appropriate. For example, it is preferable that the wavelength of the laser beam irradiated onto the first interface 13 and the third interface 17 is the same first laser beam L1. Also, the wavelength of the laser beam irradiated onto the second interface 15 and the fourth interface 19 may be the same second laser beam L2. For this reason, the first interface 13 and the third interface 17, and the second interface 15 and the fourth interface 19 may be treated as sets and irradiated with laser beams.

[0033] In some cases, depending on the scanning range of the laser beam output device, it may not be possible to scan the entire interlayer space of the laminate 10 with the laser beam. In such cases, for example, the relative positional relationship between the laminate 10 and the laser beam output device can be adjusted multiple times to enable the laser beam to scan the entire interlayer space of the laminate 10.

[0034] On the other hand, if the laser beam is spread using an appropriate lens or the like during a single laser beam irradiation, and laser beam of an appropriate wavelength is irradiated between the layers, scanning of the laser beam is not necessarily required, and it may be possible to irradiate the entire area between the layers of the laminate 10 with laser beam.

[0035] Therefore, the separation method for the laminate 10 according to this embodiment involves irradiating the first layer 12 on the surface side of the laminate 10, where adjacent layers in the stacking direction have different optical properties, with laser light to irradiate the first interface 13 between the first layer 12 and the second layer 14 superimposed on the first layer 12, and irradiating the second interface 15 between the second layer 14 and the third layer 16 superimposed on the second layer 14 on the opposite side from the first layer 12, with laser light irradiating the first interface 13 to destroy the adhesion between the first layer 12 and the second layer 14, and irradiating the second interface 15 to destroy the adhesion between the second layer 14 and the third layer 16.

[0036] Irradiating the first interface 13 with laser light includes irradiating it with first laser light L1 having a wavelength that penetrates the first layer 12 and is absorbed at the first interface 13. Irradiating the second interface 15 with laser light includes irradiating it with second laser light L2 having a wavelength that penetrates the first layer 12, the first interface 13, and the second layer 14 and is absorbed at the second interface 15.

[0037] In this embodiment, the method for separating the laminate 10 involves the following steps: the optical properties of adjacent layers in the stacking direction differ; a first laser beam L1 is transmitted through the first layer 12 on the surface side of the laminate 10 and irradiated onto the first interface 13 between the first layer 12 and the second layer 14 superimposed on the first layer 12, thereby separating the first layer 12 and the second layer 14; and a second laser beam L2, having a different wavelength from the first laser beam L1, is transmitted through the first layer 12 and the second layer 14 and irradiated onto the second interface 15 between the second layer 14 and the third layer 16 superimposed on the second layer 14, thereby separating the second layer 14 and the third layer 16.

[0038] The first laser beam L1 is transmitted through the first layer 12, the second layer 14, and the third layer 16, and irradiated onto the third interface 17 between the third layer 16 of the laminate 10 and the fourth layer 18 superimposed on the third layer 16, thereby separating the third layer 16 and the fourth layer 18.

[0039] A second laser beam L2, or a third laser beam L3 having a different wavelength from the first laser beam L1 and the second laser beam L2, is transmitted through the first layer 12, the second layer 14, the third layer 16, and the fourth layer 18, and irradiated onto the fourth interface 19 between the fourth layer 18 of the laminate 10 and the fifth layer 20 superimposed on the fourth layer 18, thereby separating the fourth layer 18 and the fifth layer 20.

[0040] In this embodiment, the layers may be separated after irradiating them with laser beams L1, L2, and L3, or the appropriate layers may be separated while irradiating them with laser beams L1, L2, and L3.

[0041] In this embodiment, laser light of appropriate output and at least two different appropriate wavelengths is irradiated between adjacent layers in the stacking direction of the laminate 10, and the entire range is scanned as needed, thereby destroying the adhesion between each layer. Then, the first layer (glass) 12 can be removed from the second layer 14 of the laminate 10. The third layer (power generation element) 16 can be removed from the fourth layer 18 of the laminate 10. In addition, the fifth layer (back sheet) 20 can be removed from the fourth layer 18 of the laminate 10. Therefore, according to the separation method of the laminate 10 in this embodiment, each layer of the laminate 10 can be separated more finely.

[0042] The first layer 12 can then be removed from the second layer 14 while maintaining its shape, and the first layer (glass) 12 can be separated from the laminate 10 as, for example, an unshattered glass plate of an appropriate size. As a result, the glass of the first layer 12 can be reused as is, or with fewer processing steps and a shorter processing time, for example, as the first layer 12 of a solar panel.

[0043] Furthermore, the third layer 16 can also be removed from the fourth layer 18 while maintaining its shape. The third layer 16 is a solar cell element and is also not crushed. This prevents the first layer (glass) 12 or unintended substances from being mixed into the third layer 16. On the other hand, it is expected that some of the EVA from the second layer 14 and the fourth layer 18 will remain attached to the third layer 16. However, by burning and refining the third layer 16 together with the second layer 14 and the fourth layer 18, high-quality metal materials can be extracted, for example.

[0044] For example, although the fourth layer 18 and the fifth layer 20 are both made of resin, by separating the fourth layer 18 and the fifth layer 20, the fourth layer 18 can be treated as a monomaterial. Therefore, even when the fourth layer 18 and the fifth layer 20 are to be disposed of, their processing can be simplified, and the environmental burden can be reduced.

[0045] Therefore, according to this embodiment, the glass material is not crushed, and the metal material is not crushed or mixed in, and the value of the recycled parts is appropriately maintained while the parts of the first layer 12 and the third layer 16 can be delivered to the manufacturer of the laminate 10, recycling companies, etc. Therefore, according to this embodiment, the processing time of the laminate 10 can be further shortened.

[0046] Therefore, according to this embodiment, it is possible to provide a method for separating a laminate 10 that allows for finer separation between each layer of the laminate 10 and shortens the processing time.

[0047] In this embodiment, the first layer 12, the second layer 14, the third layer 16, and the fourth layer 18 are described as transparent or semi-transparent, and the fifth layer 20 is described as not transparent. For example, the fifth layer 20 may be transparent. Alternatively, one or more of the second layer 14, the third layer 16, and the fourth layer 18 may be made opaque, allowing light of an appropriate wavelength to pass through.

[0048] Furthermore, if the solar panel as the laminate 10 is a double-sided panel, for example, the fifth layer 20 can be used as a common backsheet. The laminate 10 is formed symmetrically with respect to, for example, the middle surface in the thickness direction of the fifth layer 20. For example, if the solar panel as the laminate 10 is a double-sided panel, the glass layer and the battery element layer can be separated and obtained without finely crushing them by processing with laser light from the side of the first layer 12 and similarly processing with laser light from the opposite side of the first layer 12.

[0049] (modified version) Figure 2 illustrates a separation method for breaking the interlayer adhesion of the laminate 10, which is the same as in Figure 1, and separating the laminate 10 layer by layer. The arrows indicated by the symbol f in Figure 2 are used to explain the relative positional relationship between the laser beam that breaks the interlayer adhesion and the laminate 10. The relative positional relationship between the laser beam and the laminate 10 changes with scanning of the laser beam, or with feeding the laminate 10. Furthermore, the relative positional relationship between the laser beam and the laminate 10 also changes with combinations of these factors.

[0050] The laminate 10 is placed on a stand (not shown) so that laser light is irradiated from the first layer 12 side of the laminate 10.

[0051] As shown in Figure 2(A), for example, a first laser beam L1 in the mid-infrared region is irradiated onto the interface 13 between the first layer 12 and the second layer 14, preferably from a direction perpendicular to the interface 13 between the first layer 12 and the second layer 14 and facing the first layer 12. At this time, the entire interlayer space between the first layer 12 and the second layer 14 is scanned. The first laser beam L1 is absorbed on the second layer 14 side of the interface 13 between the first layer 12 and the second layer 14, destroying the molecular structure. Therefore, the interlayer adhesion between the first layer 12 and the second layer 14 is destroyed, and the first layer 12 is separated from the second layer 14, as shown in Figure 2(B). The first layer (glass) 12 is removed from the second layer 14, for example, while maintaining a rectangular shape. Therefore, the first layer 12 can be reused as is, or with fewer processing steps to shorten the processing time, for example, as the first layer 12 of a solar panel. And, with the first layer 12 removed from the laminate 10, the surface of the laminate 10 becomes the second layer 14.

[0052] Alternatively, the first layer 12 may be removed from the second layer 14 while irradiating it with the first laser beam, or the entire molecular structure of the second layer 14 at the interface 13 between the first layer 12 and the second layer 14 may be destroyed by irradiation with the first laser beam, and then the first layer 12 may be removed from the second layer 14.

[0053] As shown in Figure 2(C), for example, a second laser beam L2 in the visible light range is irradiated onto the interface 15 between the second layer 14 and the third layer 16, preferably from a direction perpendicular to the interface 15 between the second layer 14 and the third layer 16 and facing the first layer 12. At this time, the entire interlayer space between the second layer 14 and the third layer 16 is scanned. The second laser beam L2 is absorbed, for example, on the third layer 16 side of the interface 15 between the second layer 14 and the third layer 16, reducing the adhesion of the thermoplastic resin material to the interface 15 on the second layer 14 side. As a result, the second layer 14 is peeled away from the third layer 16.

[0054] Alternatively, the second layer 14 may be peeled off the third layer 16 while irradiating it with the second laser beam L2, or the second layer 14 may be removed from the third layer 16 after irradiating the entire interface 15 between the second layer 14 and the third layer 16 with the second laser beam L2.

[0055] Then, with the removal of the second layer 14 from the laminate 10, the surface of the laminate 10 becomes the third layer 16. A portion of the second layer 14 may remain in the third layer 16, specifically in the area that was the interface 15 between the second layer 14 and the third layer 16.

[0056] As shown in Figure 2(D), for example, the interface 17 between the third layer 16 and the fourth layer 18 is preferably irradiated again with a first laser beam L1 in the mid-infrared region from a direction perpendicular to the interface 17 between the third layer 16 and the fourth layer 18 and facing the third layer 16. At this time, the entire interlayer space between the third layer 16 and the fourth layer 18 is scanned. The first laser beam L1 is absorbed on the fourth layer 18 side of the interface 17 between the third layer 16 and the fourth layer 18, destroying the molecular structure. Therefore, the interlayer adhesion between the third layer 16 and the fourth layer 18 is destroyed, and as shown in Figure 2(E), the third layer 16 is separated from the fourth layer 18. In other words, the laminate 10 of the fourth layer 18 and the fifth layer 20 is separated from the third layer 16. The third layer 16 is removed from the fourth layer 18, for example, while maintaining a rectangular shape.

[0057] Note that some of the EVA from the fourth layer 18 may remain in the third layer 16. By burning and refining the third layer 16 together with the fourth layer 18, high-quality metal material can be extracted. The surface of the laminate 10 then becomes the fourth layer 18.

[0058] As shown in Figure 2(F), a laser beam in the near-infrared region (third laser beam) L3 or a second laser beam in the visible light region L2 is irradiated onto the interface 19 between the fourth layer 18 and the fifth layer 20 from a direction perpendicular to the interface 19 between the fourth layer 18 and the fifth layer 20 and facing the fourth layer 18. At this time, the entire interlayer space between the fourth layer 18 and the fifth layer 20 is scanned. The third laser beam L3 or the second laser beam L2 is absorbed, for example, on the fifth layer 20 side of the interface 19 between the fourth layer 18 and the fifth layer 20, reducing the adhesion of the thermoplastic resin material to the interface 19 on the fourth layer 18 side. As a result, the fourth layer 18 is peeled away from the fifth layer 20.

[0059] Furthermore, the fourth layer 18 may be removed from the fifth layer 20 while irradiating it with the third laser beam L3 or the second laser beam L2, or the entire molecular structure of the fifth layer 20 at the interface 19 between the fourth layer 18 and the fifth layer 20 may be destroyed by irradiation with the third laser beam L3 or the second laser beam L2, and then the fourth layer 18 may be removed from the fifth layer 20. In Figure 2(F), the fifth layer 20 appears to remain flat while the fourth layer 18 is removed, but the fifth layer 20 is also flexible and can be bent, just like the fourth layer 18.

[0060] Therefore, in this modified example, the method for separating the laminate 10 involves irradiating the first layer 12 on the surface side of the laminate 10, where adjacent layers in the stacking direction have different optical properties, with laser light passing through to the first interface 13 between the first layer 12 and the second layer 14 superimposed on the first layer 12, and irradiating the second interface 15 between the second layer 14 and the third layer 16 superimposed on the second layer 14 on the opposite side from the first layer 12, with laser light passing through both the first layer 12 and the second layer 14. When the first interface 13 is irradiated with laser light, the adhesion between the first layer 12 and the second layer 14 is destroyed, and when the second interface 15 is irradiated with laser light, the adhesion between the second layer 14 and the third layer 16 is destroyed.

[0061] Irradiating the first interface 13 with laser light includes irradiating it with first laser light L1 having a wavelength that penetrates the first layer 12 and is absorbed at the first interface 13. Irradiating the second interface 15 with laser light includes irradiating it with second laser light L2 having a wavelength that penetrates the first layer 12, the first interface 13, and the second layer 14 and is absorbed at the second interface 15.

[0062] In this modified example, the method for separating the laminate 10 involves ensuring that adjacent layers in the stacking direction have different optical properties. A first laser beam L1 is transmitted through the first layer 12 on the surface side of the laminate 10 and irradiated onto the first interface 13 between the first layer 12 and the second layer 14 superimposed on the first layer 12, thereby separating the first layer 12 and the second layer 14. Then, a second laser beam L2, having a different wavelength from the first laser beam L1, is transmitted through the first layer 12 and the second layer 14 and irradiated onto the second interface 15 between the second layer 14 and the third layer 16 superimposed on the second layer 14, thereby separating the second layer 14 and the third layer 16.

[0063] As shown in this modified example, laser light of appropriate output and at least two different appropriate wavelengths is irradiated between adjacent layers in the stacking direction of the laminate 10, and the entire range is scanned as necessary, thereby destroying the adhesion between each layer in any case. Thus, by using the method according to this modified example, a method for separating the laminate 10 into layers 12, 14, 16, 18, and 20 is provided, using multiple laser beams with different wavelengths. Therefore, according to the method for separating the laminate 10 according to this modified example, the layers of the laminate 10 can be separated more finely. Furthermore, according to this modified example, the shape of the first layer 12, the third layer 16, etc. can be maintained, and the value of the first layer 12, the third layer 16, etc. can be appropriately maintained. Therefore, according to this modified example, the processing time of the laminate 10 can be shortened.

[0064] Therefore, according to this modified example, it is possible to provide a method for separating the laminate 10 that allows for finer separation between each layer of the laminate 10 and shortens the processing time.

[0065] (Second Embodiment) The second embodiment will be described with reference to Figure 3. This embodiment is a modified version of the first embodiment, and the same reference numerals are used for the same components as those described in the first embodiment, and detailed explanations are omitted.

[0066] In the first embodiment, which includes the modified examples described above, the example was explained using a solar panel as the laminate 10. As a laminate 10 with a different structure, not limited to a solar panel, for example, the third layer 16a may be made of a material with appropriate thermal conductivity. The third layer 16a may be transparent or translucent, or it may be a metal plate (substrate). As the metal plate, for example, stainless steel, aluminum, or other appropriate metal plate may be used. The surface area of ​​the metal plate may be the same as the interface 15 with the second layer 14, or it may be formed to be larger than that.

[0067] Furthermore, while it is preferable that the materials and optical properties of the second layer 14 and the fourth layer 18 be the same, they may be different. In this embodiment, the second layer 14 and the fourth layer 18 are described as thermoplastic resin layers such as EVA, made of the same material and having the same optical properties.

[0068] A separation method for breaking the adhesion between layers of the laminate 10 and separating the laminate 10 layer by layer will be explained using Figure 3.

[0069] As shown in Figure 3(A), a second laser beam L2, for example in the visible light range, is irradiated onto the laminate 10 from the first layer 12 side. At this time, the second laser beam L2 is transmitted through the first layer (glass) 12 and the second layer (EVA) 14 and irradiated between the interface 15 between the second layer 14 and the third layer 16a. Preferably, the entire area of ​​the interface 15 between the second layer 14 and the third layer 16a is scanned. The second laser beam L2 is absorbed, for example, on the third layer 16a side of the interface 15 between the second layer 14 and the third layer 16a, and the temperature of the third layer 16a rises. As a result, the interlayer adhesion (bonding force) between the second layer 14 and the third layer 16a weakens, resulting in a state similar to that where the interlayer adhesion is broken. Weakening or reducing the adhesion between layers is equivalent to destroying the adhesion between layers. The output of the laser beam L2 may be higher than that described in the first embodiment.

[0070] Furthermore, the temperature rise of the third layer 16a is transmitted not only to the second layer 14 adjacent to the third layer 16a, but also to the interface 13 between the second layer 14 and the first layer 12 adjacent to the second layer 14. This weakens the interlayer adhesion (bonding force) between the first layer 12 and the second layer 14.

[0071] Furthermore, the temperature rise of the third layer 16a is transmitted not only to the second layer 14 adjacent to the third layer 16a, but also to the fourth layer 18 which forms an interface 17 between the third layer 16a and the interface 15 opposite to the interface 15 between the second layer 14 and the third layer 16a, and to the interface 19 between the fourth layer 18 and the fifth layer 20. As a result, the interlayer adhesion (bonding force) between the third layer 16a and the fourth layer 18 is weakened. Also, the interlayer adhesion (bonding force) between the fourth layer 18 and the fifth layer 20 is weakened.

[0072] Therefore, as shown in Figure 3(B), the heat generated in the third layer 16a by the second laser beam L2 reduces the adhesion at the interface 13 between the first layer 12 and the second layer 14. As a result, the first layer 12 separates from the second layer 14.

[0073] Furthermore, the heat generated in the third layer 16a by the second laser beam L2 reduces the adhesion at the interface 19 between the fourth layer 18 and the fifth layer 20. Consequently, the fifth layer 20 separates from the fourth layer 18.

[0074] Furthermore, at the interface 15 between the second layer 14 and the third layer 16a, the molecular structure of the second layer 14 is destroyed by the heat generated in the third layer 16a by the second laser beam L2. Therefore, as shown in Figure 3(C), the second layer 14 can be peeled off from the third layer 16a. Also, although not shown, the fourth layer 18 can be peeled off from the third layer 16a.

[0075] This heating transfers heat to the second layer 14 from the third layer 16a. In this embodiment, the second layer 14 is EVA, a thermoplastic synthetic resin. The second layer 14 is, for example, a thin film layer, and as the temperature of the second layer 14 rises and it approaches its melting point, it weakens the adhesion force at the interface 13 between the first layer 12 and the second layer 14. This makes it possible to remove the first layer 12 from the second layer 14.

[0076] Similarly, when the third layer 16a is irradiated with laser light, the fourth layer is heated by heat transferred from the third layer 16a. Here, the fourth layer 18, like the second layer 14 in this embodiment, is EVA, a thermoplastic synthetic resin. The fourth layer 18 is, for example, a thin film layer, and as the temperature of the fourth layer 18 rises and approaches its melting point, the adhesion force (bonding force) at the interface 19 between the fourth layer 18 and the fifth layer 20 weakens. This makes the fifth layer 20 removable from the fourth layer 18. The fifth layer 20 may be formed from a thermoplastic resin material, similar to EVA, but it is preferable that its melting point be set to a higher temperature than that of EVA.

[0077] Furthermore, since the second layer 14 and the fourth layer 18 adhering to the third layer 16a are also melted, for example, the second layer 14 and the fourth layer 18 can be removed from the third layer 16a, and the front and back surfaces of the third layer 16a can be exposed to the outside.

[0078] Therefore, the separation method for the laminate 10 according to this embodiment involves transmitting laser light through the first layer 12 on the surface side of the laminate, and the second layer 14 in addition to the first layer 12, which have different optical properties from adjacent layers in the stacking direction, to the second interface 15 between the second layer 14 and the third layer 16a which is superimposed on the second layer 14 on the opposite side from the first layer 12; and when the laser light is irradiated to the second interface 15, destroying the adhesion between the second layer 14 and the third layer 16a, or destroying the adhesion between the second layer 14 and the third layer 16a, and transmitting the energy of the laser light towards the first layer 12 through the second layer 14 to destroy the adhesion between the first layer 12 and the second layer 14.

[0079] Irradiating the second interface 15 with laser light includes transmitting the energy of the laser light through the third layer 16a toward the fourth layer 18 superimposed on the third layer 16a, thereby destroying the adhesion of the third interface 17 between the third layer 16a and the fourth layer 18, and / or the adhesion of the fourth interface 19 between the fourth layer 18 and the fifth layer 20 superimposed on the fourth layer 18.

[0080] The separation method for the laminate 10 according to this embodiment involves irradiating the interface 15 between the second layer 14 and the third layer 16a with laser light L2 having a wavelength that penetrates the first layer 12 and the second layer 14 superimposed on the first layer 12 and is absorbed by the third layer 16a superimposed on the second layer 14, through the first layer 12 and the second layer 14, thereby peeling the first layer 12 from the second layer 14, and peeling the fifth layer 20 from at least the fourth layer 18, which is superimposed on the third layer 16a, and the fifth layer 20 which is superimposed on the fourth layer 18. After irradiation with laser light L2, the second layer 14 and the fourth layer 18 are peeled from the third layer 16a.

[0081] By irradiating the spaces between adjacent layers in the stacking direction of the laminate 10 with laser light of an appropriate wavelength and output, and scanning the entire area as necessary, the adhesion between each layer is destroyed in any case. Thus, by using the method according to this embodiment, a method for separating the laminate 10 into its individual layers 12, 14, 16a, 18, and 20 using laser light is provided. Therefore, according to the method for separating the laminate 10 according to this embodiment, the spaces between each layer of the laminate 10 can be separated more finely. Furthermore, according to this embodiment, the shape of the first layer 12, the third layer 16a, etc. can be maintained, and the value of the first layer 12, the third layer 16a, etc. can be appropriately preserved. Therefore, according to this embodiment, the processing time of the laminate 10 can be shortened.

[0082] Therefore, according to this embodiment, it is possible to provide a method for separating a laminate 10 that allows for finer separation between each layer of the laminate 10 and shortens the processing time.

[0083] (Third embodiment) The third embodiment will be described with reference to Figure 4. This embodiment is a further modification of the first and second embodiments, and the same reference numerals are used for members that are the same as or have the same function as those described in the first and second embodiments, and detailed descriptions are omitted.

[0084] In the first embodiment described above, a solar panel was used as the laminate 10, and in the second embodiment, an example was described in which a laminate 10 with a different structure from that of the first embodiment was separated into layers. In this embodiment, any laminate 10 may be used, but the laminate 10 in Figure 4 is described as being the same as the laminate 10 described in the second embodiment (see Figure 3).

[0085] A separation method for breaking the adhesion between layers of the laminate 10 and separating the laminate 10 will be explained using Figure 4.

[0086] As shown in Figure 4(A), a second laser beam L2, for example in the visible light range, is irradiated onto the laminate 10 from the first layer 12 side. At this time, the second laser beam L2 is transmitted through the first layer (glass) 12 and the second layer (EVA) 14 and irradiated onto the interface 15 between the second layer 14 and the third layer 16a. Preferably, the entire area of ​​the interface 15 between the second layer 14 and the third layer 16a is scanned. The second laser beam L2 is absorbed, for example, on the third layer 16a side of the interface 15 between the second layer 14 and the third layer 16a, causing the temperature of the third layer 16a to rise. Heat is then transferred not only to the interface 17 between the third layer 16a and the fourth layer 18, but also to the interface 19 between the fourth layer 18 and the fifth layer 20. Therefore, the adhesion between the fourth layer 18 and the fifth layer 20 is weakened, and the fifth layer 20 can be peeled off the fourth layer 18.

[0087] Furthermore, as shown in Figure 4(B), the adhesion between the second layer 14 and the third layer 16a is weakened, allowing the second layer 14 to be peeled off from the third layer 16a together with the first layer 12.

[0088] As shown in Figure 4(C), in the member in which the first layer 12 and the second layer 14 are integrated, the metal plate 30 is placed from the side opposite to the first layer 12. For this reason, instead of the third layer 16a, a metal plate 30 or the like is placed beneath the laminate 10 of the first layer 12 and the second layer 14. The metal plate 30 is made of a material with higher thermal conductivity than the third layer 16a.

[0089] Again, a second laser beam L2, which penetrates the first layer 12 and the second layer 14, is used to cause the metal plate 30, which serves as the third layer, to absorb the laser beam L2. This heats the metal plate 30. As the temperature of the metal plate 30 rises, the interface 13 between the first layer 12 and the second layer 14 melts due to the heat, in addition to the interface 31 between the second layer 14 and the metal plate 30. Therefore, the adhesion between the first layer 12 and the second layer 14 is weakened, allowing the first layer 12 to be removed from the second layer 14. Thus, the first layer 12 is separated from the second layer 14.

[0090] Therefore, the separation method for the laminate 10 according to this embodiment involves transmitting laser light through the first layer 12 and the second layer 14 on the surface side of the laminate, where adjacent layers in the stacking direction have different optical properties, and irradiating the second interface 15 between the second layer 14 and the third layer 16a, which is superimposed on the second layer 14 on the opposite side from the first layer 12. When the laser light is irradiated onto the second interface 15, the adhesion between the second layer 14 and the third layer 16a is broken.

[0091] Furthermore, irradiating the second interface 15 with laser light includes transmitting the energy of the laser light through the third layer 16a to the fourth layer 18 superimposed on the third layer 16a, thereby destroying the adhesion of the third interface 17 between the third layer 16a and the fourth layer 18, and / or the adhesion of the fourth interface 19 between the fourth layer 18 and the fifth layer 20 superimposed on the fourth layer 18.

[0092] The separation method for the laminate 10 according to this embodiment involves irradiating the interface 15 between the second layer 14 and the third layer 16a with laser light L2 having a wavelength that penetrates the first layer 12 and the second layer 14 superimposed on the first layer 12 and is absorbed by the third layer 16a superimposed on the second layer 14, through the first layer 12 and the second layer 14, thereby peeling the second layer 14 from the third layer 16a, and peeling the fifth layer 20 from at least the fourth layer 18, of the fourth layer 18 superimposed on the third layer 16a and the fifth layer 20 superimposed on the fourth layer 18. Then, the second layer 14, on which the first layer 12 is superimposed, is placed on a metal plate 30 that absorbs laser light L2, and while irradiating the metal plate 30 with laser light L2 through the first layer 12 and the second layer 14, the adhesion of the first layer 12 to the second layer 14 is broken.

[0093] By irradiating the spaces between adjacent layers in the stacking direction of the laminate 10 with laser light of an appropriate wavelength and output, and scanning the entire area as necessary, the adhesion between each layer is destroyed in any case. Thus, by using the method according to this embodiment, a method for separating the laminate 10 into individual layers 12, 14, 16a, 18, and 20 using laser light is provided. Therefore, according to the method for separating the laminate 10 according to this embodiment, the spaces between each layer of the laminate 10 can be separated more finely. Furthermore, according to this embodiment, the shape of the first layer 12, the third layer 16a, etc. can be maintained, and the value of the first layer 12, the third layer 16a, etc. can be appropriately maintained. Therefore, according to this embodiment, the processing time of the laminate 10 can be shortened.

[0094] Therefore, according to this embodiment, it is possible to provide a method for separating a laminate 10 that allows for finer separation between each layer of the laminate 10 and shortens the processing time.

[0095] According to at least one of these embodiments, a method for separating the laminate 10 can be provided that allows for finer separation between each layer of the laminate 10 and reduces processing time.

[0096] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0097] 10...Laminate, 12...First layer, 13...First interface, 14...Second layer, 15...Second interface, 16,16a...Third layer, 17...Third interface, 18...Fourth layer, 19...Fourth interface, 20...Fifth layer, 30...Metal plate.

Claims

1. The laser beam is transmitted through the first layer on the surface side of a laminate where adjacent layers in the stacking direction have different optical properties, irradiating at least one of the first interface between the first layer and a second layer superimposed on the first layer, and the laser beam is transmitted through the second layer in addition to the first layer, irradiating at least one of the second interface between the second layer and a third layer superimposed on the second layer on the opposite side from the first layer. When the laser light is irradiated onto the first interface, the adhesion between the first layer and the second layer is destroyed, or the adhesion between the first layer and the second layer is destroyed, and the energy of the laser light is transmitted through the second layer to the third layer, destroying the adhesion between the second layer and the third layer. When the laser light is irradiated onto the second interface, the adhesion between the second layer and the third layer is destroyed, or the adhesion between the second layer and the third layer is destroyed, and the energy of the laser light is transmitted through the second layer to the first layer, destroying the adhesion between the first layer and the second layer. A method for separating laminates, comprising the characteristics of a laminate.

2. Irradiating the first interface with the laser light includes irradiating it with first laser light having a wavelength that penetrates the first layer and is absorbed at the first interface, Irradiating the second interface with the laser light includes irradiating the first layer, the first interface, and the second layer with a second laser light having a wavelength that penetrates the second layer and is absorbed at the second interface. The separation method according to claim 1.

3. Irradiating the second interface with the laser light includes transmitting the energy of the laser light through the third layer to the fourth layer superimposed on the third layer, thereby destroying the adhesion of the third interface between the third layer and the fourth layer, and / or the adhesion of the fourth interface between the fourth layer and the fifth layer superimposed on the fourth layer. The separation method according to claim 1.

4. The optical properties of adjacent layers in the stacking direction are different, and a first laser beam is transmitted through the first layer on the surface side of the stacked material and irradiated onto the first interface between the first layer and the second layer superimposed on the first layer, thereby separating the first layer and the second layer. A second laser beam, having a different wavelength from the first laser beam, is transmitted through the first and second layers and irradiated onto the second interface between the second layer of the laminate and the third layer superimposed on the second layer, thereby separating the second layer and the third layer. A method for separating laminates, comprising the characteristics of a laminate.

5. The first laser beam is transmitted through the first layer, the second layer, and the third layer, and irradiated onto the third interface between the third layer of the laminate and the fourth layer superimposed on the third layer, thereby separating the third layer and the fourth layer. The separation method according to claim 4, further comprising the above.

6. The second laser beam, or a third laser beam having a different wavelength from the first and second laser beams, is transmitted through the first, second, third, and fourth layers, and irradiated onto the fourth interface between the fourth layer of the laminate and the fifth layer superimposed on the fourth layer, thereby separating the fourth layer and the fifth layer. The separation method according to claim 5, further comprising the above.

7. The wavelength of the first laser light is one that penetrates the first layer and is absorbed by the second layer. The separation method according to claim 4.

8. The wavelength of the second laser light is one that passes through the first and second layers and is absorbed by the third layer. The separation method according to claim 4.

9. The wavelength of the first laser light is one that penetrates the first, second, and third layers and is absorbed by the fourth layer. The separation method according to claim 5.

10. The wavelength of the second or third laser light is such that it passes through the first, second, third, and fourth layers and is absorbed by the fifth layer. The separation method according to claim 6.

11. As the first layer, a transparent glass layer is used. The second layer is a first thermoplastic resin layer that adheres closely to the glass layer and absorbs or transmits light depending on the wavelength of light. As the third layer, a solar cell layer is provided that adheres closely to the thermoplastic resin layer and exhibits a photovoltaic effect, generating electromotive force when exposed to light, while absorbing and transmitting light according to the wavelength of light. As the fourth layer, a second thermoplastic resin layer is provided that is in close contact with the solar cell layer and absorbs and transmits light according to the wavelength of light. The fifth layer is a backsheet layer made of a resin material that adheres closely to the thermoplastic resin layer and protects the solar cell layer, and which absorbs and transmits light according to the wavelength of light. The separation method according to claim 6.

12. A laser beam with a wavelength that passes through the first layer and the second layer superimposed on the first layer and is absorbed by the third layer superimposed on the second layer is irradiated through the first layer and the second layer to the interface between the second layer and the third layer, thereby causing the first layer to be peeled off from the second layer, and of the fourth layer superimposed on the third layer and the fifth layer superimposed on the fourth layer, at least the fourth layer is peeled off from the fourth layer. After irradiation with the laser light, the second layer and the fourth layer are peeled off from the third layer. A method for separating laminates, comprising the characteristics of a laminate.

13. A laser beam with a wavelength that passes through the first layer and the second layer superimposed on the first layer and is absorbed by the third layer superimposed on the second layer is irradiated through the first layer and the second layer to the interface between the second layer and the third layer, thereby causing the second layer to peel off from the third layer, and of the fourth layer superimposed on the third layer and the fifth layer superimposed on the fourth layer, at least the fifth layer to peel off from the fourth layer. The second layer, on which the first layer is superimposed, is placed on a plate that absorbs laser light, and the laser light is shone onto the plate through the first and second layers, thereby breaking the adhesion of the first layer to the second layer. A method for separating laminates, comprising the characteristics of a laminate.

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