Glass peeling method

Abstract

The plate-like glass (2) having a printed layer bonded to the substrate (5) via the adhesive layer (4) can be peeled in layers from the article (1) by irradiating the printed layer (3) with laser light (6), carbonizing the organic component in the entire surface of the printed layer by irradiation, and peeling the printed layer in layers.

Description

Technical Field

[0001] The present invention relates to a method for peeling glass, wherein only a printed layer existing between the glass and an adhesive layer is carbonized by laser, thereby peeling a plate-shaped glass in layers. Background Art

[0002] Due to economic activities involving large amounts of consumption and waste, global environmental problems such as global warming and resource depletion have arisen.

[0003] In such a situation, in order to build a resource recycling society, the Home Appliance Recycling Law was implemented in Japan in April 2001. The Home Appliance Recycling Law requires the recycling of used home appliances (air conditioners, televisions, refrigerators, freezers, washing machines, clothes dryers, etc.). As a result, used home appliances are broken into small pieces at home appliance recycling factories, and then separated and recycled by material type using magnetism, wind power, or vibration, and then recycled as recycled materials.

[0004] In recent years, the number of home appliances that use glass instead of conventional metal plates or resins has increased due to their high design properties. Examples of products that use glass include refrigerators, washing machines, and IH stoves.

[0005] However, from the perspective of recycling, the glass used in the glass door of a glass door refrigerator accounts for 7-8% of the weight of the refrigerator body, which is expected to have a significant impact on the future recycling rate of home appliances. In addition, it is assumed that the glass will cause problems such as wear of the blades of the crusher in the recycling plant (RP) or mixing of glass residues in the later process. As of 2022, the problem has not yet become apparent due to the small amount, but it is considered that glass will be mixed into recycled materials due to the increase in the use of glass products. As a result, the recycled materials will be disposed of as industrial waste, and there is a concern that the recycling rate will be reduced. For this reason, technology is needed to remove the glass in the pre-process of crushing the recycled products.

[0006] However, it is difficult to easily remove the glass from the product. This is because, in the structure where the aesthetic glass is bonded to the substrate, the glass and the substrate are firmly bonded to each other with an adhesive material over the entire surface, so it is very difficult to peel the glass from the product. In addition, if the glass is peeled off while being broken, it becomes impossible to recycle the peeled glass, and the glass must be peeled off from the product piece by piece.

[0007] Patent Document 1 proposes a method that takes the above-mentioned issues into consideration. As the background for the development of this method, in the recycling of smartphones, laser light is irradiated on the object to be peeled off, so that the printed layer absorbs and generates heat, and the heat is transmitted to the adhesive layer, thereby causing chemical reactions such as softening, melting, foaming, and decomposition. This method is to separate the glass from the product by reducing the adhesive force by utilizing these reactions.

[0008] Prior Art Literature

[0009] Patent Literature

[0010] Patent Document 1: JP Patent No. 6009540 Summary of the invention

[0011] A glass stripping method according to one embodiment of the present invention strips a plate-shaped glass from an article having the plate-shaped glass attached to the surface thereof, wherein a laser is irradiated to a printed layer of the article through the plate-shaped glass, wherein an adhesive layer and the printed layer containing an organic component are provided between the plate-shaped glass and a substrate of the article so that the adhesive layer becomes the substrate side, the organic component in the entire surface of the printed layer is carbonized by irradiating the laser, and the printed layer is stripped in layers, thereby stripping the plate-shaped glass from the article. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of laser processing in an embodiment of the present invention.

[0013] Figure 2 It is a schematic diagram of the peeling method in the embodiment of the present invention.

[0014] Figure 3 It is a flowchart in the embodiment of the present invention.

[0015] Figure 4 This is a graph showing the relationship between the pulse energy density and the extraction force involved in peeling obtained in the embodiment of the present invention.

[0016] Figure 5 This is a schematic diagram of a case where peeling cannot be achieved by high energy in an embodiment of the present invention.

[0017] Figure 6 This is a graph showing the relationship between pulse energy density and beam thermal diffusion obtained in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The invention according to Patent Document 1 is effective in that the heat generated by laser light in the aesthetic printing can be used to separate the adhesive layer.

[0019] However, in the method of spreading heat, it is assumed that it will take time for large products such as refrigerators to become peelable compared to small products such as smartphones. In addition, in the structure bonded by the adhesive material, after the laser is irradiated, the softened adhesive layer will be fixed to the resin or glass over time, and thus it will eventually become impossible to peel off. Therefore, when considering the application to a variety of products, it is more necessary to reduce the influence of re-fixation by processing only the printed layer rather than causing a chemical reaction in the adhesive material.

[0020] The present invention solves the above-mentioned conventional problems and aims to provide a method for peeling glass by using laser to carbonize only the printed layer without damaging the adhesive layer in the structure where the glass and the substrate are bonded, thereby peeling the glass from the object in layers.

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0022] (Implementation Method)

[0023] As an example of an article Figure 1 The irradiated sample 1 shown has a structure in which a printed layer 3 exists on the back of a plate-shaped glass 2, and the printed layer 3 is bonded to a substrate 5 of an article by an adhesive layer 4. In other words, in the irradiated sample 1, an adhesive layer 4 and a printed layer 3 containing an organic component are provided between the plate-shaped glass 2 and the substrate 5 of the irradiated sample 1, so that the adhesive layer 4 is on the substrate side. The laser light 6 irradiated from above the glass side of the irradiated sample 1 passes through the plate-shaped glass 2 and is absorbed inside the printed layer 3, thereby carbonizing the printed layer 3 and moving toward the substrate 5. Figure 2 The printed layer carbide 7 shown in FIG. 1 is deteriorated.

[0024] The plate glass 2 can be made of, for example, soda glass or borosilicate glass, etc. The plate glass 2 may be colorless and transparent, but may be colored as long as it can transmit most of the laser light 6 .

[0025] The printed layer 3 is formed by using various printing methods such as offset printing, gravure printing, or screen printing.

[0026] The printed layer 3 is composed of, for example, organic and inorganic compounds, and is deposited, printed, or laminated on glass. Since it is ultimately necessary to carbonize it, it is necessary to include compounds containing carbon atoms and organic substances. As the component of the organic coating, any component having an azo group or a polycyclic organic compound such as a phthalocyanine or quinone type may be used.

[0027] The printed layer 3 needs to be non-transmissive to the laser beam 6. Non-transmissive means that the printed layer 3 absorbs the laser beam 6 when irradiated with the laser beam 6.

[0028] In addition, a metal vapor-deposited film may be provided between the printed layer 3 and the plate-shaped glass 2. In this case, the metal vapor-deposited film needs to be decomposed by laser irradiation, and layer-like peeling can be achieved in the printed layer 3.

[0029] As the bonding material constituting the adhesive layer 4, for example, can enumerate the bonding material of acrylic acid. In addition, as bonding material, can use the bonding material of elastic system, in this case, for example, can enumerate acrylic acid elastomer, urethane elastomer, polyolefin elastomer or styrene elastomer. In addition, as bonding material, can also use general rubber-based bonding material. As bonding material, certainly can be monomer, also can use the structure of the such substrate surface coating bonding material of double-sided tape. In addition, as bonding material, also can be the structure that the bonding material of different types mixes and exists.

[0030] The substrate 5 is made of, for example, resin, metal, ceramic or foamed urethane, and needs to be able to adhere to the adhesive layer 4 .

[0031] The type of laser 6 is not particularly limited, and examples thereof include solid lasers such as Nd:YAG lasers, and short pulse lasers such as nanosecond lasers. In particular, in consideration of the improvement of the processing speed, by using a top hat type beam profile instead of a Gaussian type, the processing speed can be improved while suppressing the thermal influence on the adhesive layer 4.

[0032] The wavelength of the laser 6 is preferably 300 nm to 3 μm, and particularly preferably 355 nm to 2 μm. By setting the wavelength of the laser to the above range of 300 nm to 3 μm, the printed layer 3 can be carbonized under the optimal laser output through the plate glass 2, thereby improving the efficiency and reliability of carbonization.

[0033] Figure 2 The peeling method shown shows that the printed layer 3 is carbonized after irradiation with the laser 6 to form the printed layer carbide 7 , and the printed layer carbide 7 attached to the surface of the plate glass 2 is peeled from the irradiated sample 1 using a peeling tool 8 .

[0034] The printed layer 3 is carbonized by irradiation with the laser beam 6 , thereby forming a printed layer carbide 7 .

[0035] It is desirable that the peeling tool 8 can fix only the surface of the plate-shaped glass 2, and, for example, a suction pad that can suck and hold the surface of the glass 2 can be used.

[0036] Here, use Figure 3 An example of the glass peeling method according to the embodiment will be described.

[0037] Figure 3This is a flowchart involved in the implementation method.

[0038] In this embodiment, the irradiation of the sample 1 is performed using a refrigerator glass door.

[0039] In step S01, an irradiation sample 1 is set for irradiation with laser 6. In the embodiment, the irradiation sample 1 is a refrigerator glass door. The thickness of the printed layer 3 is 5 to 200 μm. The irradiation sample 1 is set to be perpendicular to the laser 6 at the shortest distance to the surface of the plate glass 2.

[0040] Next, in step S02, the laser 6 is passed through the plate glass 2 and irradiated onto the printed layer 3 of the irradiated sample 1. The laser 6 has a wavelength of 1064nm and oscillates with a pulse output of 200W and 70 to 600 nanoseconds. The laser 6 is irradiated on the glass door of the refrigerator so that the printed layer 3 is carbonized on the entire surface. As a scanning method, a laser galvanometer is used to generate a line light that matches the size of the door glass, and is implemented at a scanning speed of 10 to 40 m / s. The focusing diameter is set to 410μm. The number of irradiations of the laser 6 can be one or more times. If the output of the laser 6 is low and the same part is irradiated multiple times, the printed layer 3 is slowly and continuously processed when the thickness of the printed layer 3 is thin, then the thermal influence on the adhesive layer 4 can be suppressed. As a result, peeling can also be performed in the irradiated sample 1 with a thin printed layer 3.

[0041] Next, in step S03, the glass is peeled off from the irradiated sample 1 processed in step S02. After confirming that the printed layer 3 changes to the printed layer carbide 7, the peeling tool 8 is set on the surface of the plate glass 2. The peeling tool 8 uses an adsorption pad that can adsorb and hold the surface of the glass 2. That is, after the surface of the plate glass 2 is adsorbed and held by the adsorption pad, a force is applied to the plate glass 2 in the opposite direction to the direction in which the adhesive layer 4 exists, thereby peeling the printed layer carbide 7 in layers, and peeling the plate glass 2 from the refrigerator glass door.

[0042] exist Figure 4 The pulse energy density required to carbonize the printed layer 3 is shown. In this case, when the force applied by the adsorption pad is 50N or less, it is defined as being able to perform the peeling operation. The reason for this is that the force that can be continuously performed by manual work is taken into account in the peeling method using the peeling tool 8. As a result, it is possible to perform the peeling operation with a pulse energy density of 0.5J / cm 2 The above peeling operation is performed if the pulse energy density is greater than 9.0J / cm 2 If the pulse energy density is less than 0.5 J / cm 2 On the other hand, when the pulse energy density is greater than 9.0 J / cm 2In the case of , although carbonization itself can be performed, the laser energy propagates not only to the printed layer 3 but also to the adhesive layer 4, so that the adhesive layer 4 melts and precipitates to the plate-shaped glass 2, thereby making it impossible to perform the peeling operation.

[0043] This phenomenon Figure 5 In the sample 9 after high energy irradiation, the printed layer carbide 7 and the adhesive layer 4 are mixed by laser irradiation, thereby forming an adhesive layer melt 10. The formed adhesive layer melt 10 naturally cools on the surface of the plate glass 2 due to the passage of time, and thus is fixed at the time of the peeling operation. Therefore, it is considered that the peeling operation cannot be performed at high energy.

[0044] The minimum pulse energy required to carbonize the printed layer 3 is 0.5 J / cm 2 As described above, when there is a margin with respect to the pulse energy of the laser output, the region larger than the beam diameter can be processed while utilizing the influence of thermal diffusion in the energy density region where the adhesive layer 4 does not melt.

[0045] exist Figure 6 The relationship between pulse energy density and beam thermal diffusivity is shown. It can be seen that at a pulse energy density of 1.4 J / cm 2 When , the treatment diameter is substantially the same as the beam diameter, and the beam thermal diffusivity increases with the increase in pulse energy density. If an approximate line is drawn from this result, an approximate curve represented by the following formula (1) can be drawn.

[0046] Beam thermal diffusivity P = 63.518lnx + 75.812… (1)

[0047] Here, P is the beam thermal diffusivity and x is the pulse energy density.

[0048] Based on the equation (1), and in relation to the pulse energy density required for carbonization, it can be seen that at a pulse energy density of 0.5 J / cm 2 When the beam thermal diffusivity is 32%, the pulse energy density is 9.0 J / cm 2 When , the beam thermal diffusivity is 215%.

[0049] In the peeling method according to this embodiment, it is necessary to carbonize the entire surface of the printed layer 3. By adopting a pulse energy density with a high thermal diffusivity, the treatment area per pulse can be increased, and the effect of shortening the treatment time can be expected.

[0050] As described above, according to the glass stripping method involved in the embodiment, the printed layer 3 is irradiated with the laser 6 to carbonize the organic components in the entire surface of the printed layer 3, and the printed layer 3 is stripped in layers, so that the plate glass 2 having the printed layer 3 bonded to the substrate 5 via the adhesive layer 4 can be stripped in layers from the article 1.

[0051] Here, in order to peel off the printed glass 2 adjacent to the adhesive layer 4 without breaking, it is necessary to inactivate the adhesive component of the glass 2 and the entire surface of the object, such as the door of a refrigerator. However, in a structure bonded by the adhesive layer 4, after irradiation with the laser 6, the softened adhesive layer 4 will be fixed to the resin or glass 2 again over time, and peeling becomes impossible. Therefore, when considering the application to various products, if only the printed layer 3 is treated, the influence of re-fixation can be reduced.

[0052] Therefore, by using the laser 6 to carbonize only the printed layer 3 without damaging the adhesive layer 4 between the glass 2 and the substrate 5, the glass 2 is peeled off from the substrate 5 in layers. That is, by irradiating the printed layer 3 with the laser 6 through the glass 2, the organic components in the entire surface of the printed layer 3 are carbonized, and the printed layer 3 is peeled off in layers, so that the plate-shaped glass 2 can be peeled off from the article 1 in layers.

[0053] In addition, by appropriately combining any of the various embodiments or variations, the effects possessed by each can be achieved. In addition, it can be a combination of the embodiments, a combination of the embodiments, or a combination of the embodiments and the embodiments, and it can also be a combination of the features in different embodiments or embodiments.

[0054] As described above, according to the glass stripping method involved in the embodiment of the present invention, the printed layer is irradiated with the laser to carbonize the organic components in the entire surface of the printed layer, and the printed layer is stripped in layers. Therefore, a plate-shaped glass having a printed layer bonded to a substrate via an adhesive layer can be stripped in layers from an object.

[0055] Industrial Applicability

[0056] As described above, the glass peeling method according to the embodiment of the present invention can peel off a plate glass having a printed layer bonded to a substrate by an adhesive layer 4 at high speed, and is applicable to large products such as refrigerators and IH stoves in addition to small products such as smartphones.

[0057] Description of Reference Numerals

[0058] 1 Irradiate the sample

[0059] 2 Plate glass

[0060] 3 Printing layer

[0061] 4 Adhesive layer

[0062] 5. Substrate

[0063] 6 Laser

[0064] 7 Printing layer carbide

[0065] 8 Stripping tools

[0066] 9 Samples after high energy irradiation

[0067] 10 Adhesive layer melt.

Claims

1. A method for peeling glass, comprising peeling a plate-shaped glass from an article to which the plate-shaped glass is attached. In the article, the printed layer is irradiated with laser light through the plate-shaped glass, wherein: An adhesive layer and the printed layer containing an organic component are provided between the plate-shaped glass and the substrate of the article so that the adhesive layer is on the substrate side. The organic components in the entire surface of the printed layer are carbonized by irradiation with the laser beam, and the printed layer is peeled off in layers, thereby peeling the plate-shaped glass from the article.

2. The glass peeling method according to claim 1, wherein: The thickness of the printing layer is 5 to 200 μm. The pulse energy density of the laser when irradiating the laser is 0.5 J / cm 2 Above and 9J / cm 2 the following.

3. The glass peeling method according to claim 1 or 2, wherein: The beam thermal diffusivity after laser irradiation is 32% or more and 215% or less.

4. The glass peeling method according to claim 1 or 2, wherein: The wavelength of the laser light during irradiation is 300 nm to 3 μm.

5. The glass peeling method according to claim 3, wherein: The wavelength of the laser light during irradiation is 300 nm to 3 μm.

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