Multilayer structure and method for manufacturing the same

Abstract

The multilayer structure has a resin layer, a glass layer laminated on the resin layer by an adhesive, and a fusion layer formed on the outer peripheral portion of the glass layer on the adhesive side, the thickness of the glass layer is 10 μm or more and 300 μm or less, and the thickness of the fusion layer is less than 3 μm.

Description

Technical Field

[0001] This invention relates to a multi-layer structure and its manufacturing method. Background Technology

[0002] Multilayer structures composed of two or more layers are known. As an example, a multilayer structure in which a silver reflective layer is laminated on a thin glass layer (glass film). The thickness of the multilayer structure is, for example, in the range of 1.0 to 200 μm. The multilayer structure is, for example, obtained by forming a glass roller using a downward drawing method.

[0003] <Prior art documents>

[0004] <Patent Documents>

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-231744 Summary of the Invention

[0006] <Problem to be solved by this invention>

[0007] As mentioned above, thin glass layers are very brittle and prone to cracking, and have poor workability. For example, there are proposals to reinforce multilayer structures by attaching a resin layer to one side of the glass layer to improve workability.

[0008] However, the problem of cracking in the glass layer of a multilayer structure with a thin glass layer stacked on top of a resin layer has not been fully resolved.

[0009] The present invention is made in view of the above points, and its purpose is to provide a multilayer structure in which the glass layer is not prone to cracking.

[0010] <Methods for solving problems>

[0011] This multilayer structure includes: a resin layer, a glass layer laminated on the resin layer by an adhesive layer, and a molten layer formed on the adhesive layer side of the outer periphery of the glass layer, wherein the thickness of the glass layer is 10 μm or more and 300 μm or less, and the thickness of the molten layer is less than 3 μm.

[0012] <The Effects of the Invention>

[0013] According to the publicly available technology, it is possible to provide multi-layer structures in which the glass layers are less prone to cracking. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view illustrating the multilayer structure according to the first embodiment.

[0015] Figure 2 This is a bottom view illustrating the multilayer structure according to the first embodiment.

[0016] Figure 3 This is a partially enlarged cross-sectional view of the area near the outer periphery of the multilayer structure according to the first embodiment.

[0017] Figure 4 This is a diagram (1) illustrating the manufacturing process of the multilayer structure according to the first embodiment.

[0018] Figure 5 This is a diagram (Figure 2) illustrating the manufacturing process of the multilayer structure according to the first embodiment.

[0019] Figure 6 This is a diagram (3) illustrating the manufacturing process of the multilayer structure according to the first embodiment.

[0020] Figure 7 This is a diagram (4) illustrating the manufacturing process of the multilayer structure according to the first embodiment.

[0021] Figure 8 This is a diagram (5) illustrating the manufacturing process of the multilayer structure according to the first embodiment.

[0022] Figure 9 This is a diagram (6) illustrating the manufacturing process of the multilayer structure according to the first embodiment.

[0023] Figure 10 This is a cross-sectional view of a multilayer structure according to a variation of the first embodiment 1.

[0024] Figure 11 This is a plan view illustrating the multi-layer structure according to the first embodiment.

[0025] Figure 12 This is a partially enlarged cross-sectional view of the periphery of the multilayer structure involved in the first embodiment, variation 1.

[0026] Figure 13 This is a diagram (1) illustrating the manufacturing process of a multilayer structure according to a variation of the first embodiment (Example 1).

[0027] Figure 14 This is a diagram (2) illustrating the manufacturing process of a multilayer structure according to a variation of the first embodiment 1.

[0028] Figure 15 This is a cross-sectional view of a multilayer structure according to a variation of the first embodiment, Example 2. Detailed Implementation

[0029] Hereinafter, the methods for carrying out the invention will be described with reference to the accompanying drawings. In the drawings, the same symbols are used for the same structural parts, and sometimes repeated descriptions are omitted.

[0030] <First Embodiment>

[0031] [Multi-layer structure]

[0032] Figure 1 This is a cross-sectional view illustrating the multilayer structure according to the first embodiment. Figure 2 This is a bottom view illustrating the multilayer structure according to the first embodiment, and is a view of the multilayer structure viewed from the underside of the resin layer.

[0033] like Figure 1 as well as Figure 2 As shown, the multilayer structure 1 includes a resin layer 10, an adhesive layer 20, and a glass layer 30. The resin layer 10 has a top surface 10a, a bottom surface 10b, and a side surface 10c. The glass layer 30 has a top surface 30a, a bottom surface 30b, and a side surface 30c. In the multilayer structure 1, the glass layer 30 is laminated onto the top surface 10a of the resin layer 10 via the adhesive layer 20. That is, the adhesive layer 20 bonds the top surface 10a of the resin layer 10 to the bottom surface 30b of the glass layer 30.

[0034] The planar shape of the multilayer structure 1 (the shape viewed from the normal direction of the top surface 30a of the glass layer 30) is, for example, rectangular. However, it is not limited to this; the planar shape of the multilayer structure 1 can be circular, elliptical, or a combination thereof, or other suitable shapes. The multilayer structure 1 is flexible and therefore can be easily attached to curved surfaces.

[0035] In this embodiment, as an example, the planar shape of the multilayer structure 1 is rectangular. Specifically, in this embodiment, as an example, the planar shape of the resin layer 10 is rectangular, and the planar shape of the glass layer 30 is a rectangle larger than that of the resin layer 10. Furthermore, the side surface 10c of the resin layer 10 is an inclined surface forming an angle of less than 90 degrees with the top surface 10a of the resin layer 10. That is, the cross-sectional shape of the resin layer 10 is trapezoidal. Furthermore, the cross-sectional shape of the glass layer 30 is rectangular. When viewed from the bottom, the outer periphery of the bottom surface 30b of the glass layer 30 is exposed around the side surface 10c of the resin layer 10.

[0036] However, due to the manufacturing method of the multilayer structure 1, sometimes when viewed from the bottom, the resin layer 10 and the glass layer 30 are the same size. Furthermore, sometimes when viewed from the bottom, only one side of the resin layer 10 has the outer periphery of the lower surface 30b of the glass layer 30 exposed, or the outer periphery of the lower surface 30b of the glass layer 30 exposed on two or three sides of the resin layer 10. Moreover, it is not limited to all sides 10c of the resin layer 10 being inclined surfaces; sometimes a portion of the side surface 10c is approximately perpendicular to the upper surface 10a and the lower surface 10b.

[0037] Figure 3This is a partially enlarged cross-sectional view of the area near the outer periphery of the multilayer structure according to the first embodiment. For example... Figure 3 As shown, a molten layer 35 is sometimes formed on the adhesive layer 20 side of the outer periphery of the glass layer 30. The molten layer 35 is sometimes formed in a generally annular shape on the outer periphery of the glass layer 30. The cross-sectional shape of the molten layer 35 is, for example, fan-shaped. The molten layer 35 is continuously exposed on the lower surface 30b and the side surface 30c of the glass layer 30. The thickness T1 of the molten layer 35 is less than 3 μm.

[0038] The thickness T1 of the molten layer 35 is the value of the thickest part of the molten layer 35 when measured in the vertical direction of the lower surface 30b of the glass layer 30, using the lower surface 30b as a reference. The thickness T1 of the molten layer 35 will not reach 3 μm regardless of where it is measured on the side surface 30c of the glass layer 30. The thickness T1 of the molten layer 35 can be measured, for example, by observation using a microscope. Alternatively, the thickness T1 of the molten layer 35 can also be measured using the Senarmont method.

[0039] Furthermore, the thickness T1 of the fused layer 35 only needs to be less than 3 μm, or even 0 μm. That is, the fused layer 35 can be absent. The fused layer 35 is formed by irradiating the resin layer 10 with a laser during the manufacturing process of the multilayer structure 1. However, during the manufacturing process of the multilayer structure 1, sometimes the entire fused layer 35 is removed, in which case the thickness T1 of the fused layer 35 becomes 0 μm. The manufacturing process of the multilayer structure 1 will be explained later.

[0040] Furthermore, in the multilayer structure 1, the outer periphery of the glass layer 30 protrudes horizontally from the upper end of the side surface 10c of the resin layer 10. The amount P1 of the protrusion P1 from the upper end of the side surface 10c of the resin layer 10 is preferably less than 15 μm. By making the protrusion P1 less than 15 μm, the thickness T1 of the molten layer 35 can be made thinner. Alternatively, the protrusion P1 can also be 0 μm. That is, in top view, the outer edge of the resin layer 10 and the outer edge of the glass layer 30 can be aligned.

[0041] The following describes the materials of each part of the multi-layer structure 1.

[0042] [Resin Layer]

[0043] The resin layer 10 serves as a substrate for stacking glass layers 30, etc., and is flexible. The resin layer 10 consists of one or more layers. When the resin layer 10 is formed of multiple layers, it is preferable to stack them using close-fitting layers with adhesive properties. From the viewpoint of flexibility, the total thickness of the resin layer 10 is acceptable as long as it is 20 μm to 1000 μm, preferably 25 μm to 500 μm, and more preferably 50 μm to 200 μm. When the resin layer 10 consists of a single layer, its thickness can, for example, be in the range of 30 μm to 50 μm.

[0044] Examples of materials for the resin layer 10 include, for example, polyester resins such as polyethylene terephthalate resins and polyethylene naphthalate resins, cycloolefin resins such as norbornene resins, polyethersulfone resins, polycarbonate resins, acrylic resins, polyolefin resins, polyimide resins, polyamide resins, polyimide amide resins, polyarylate resins, polysulfone resins, polyetherimide resins, cellulose resins, and urethane resins.

[0045] [Adhesive layer]

[0046] As the adhesive layer 20, any suitable adhesive may be used. The thickness of the adhesive layer 20 is, for example, 0.5 μm to 25 μm. As the adhesive layer 20, for example, acrylic adhesives, silicone adhesives, rubber adhesives, UV-curable acrylic adhesives, UV-curable epoxy adhesives, thermosetting epoxy adhesives, thermosetting melamine adhesives, thermosetting phenol adhesives, ethylene vinyl acetate (EVA) interlayers, polyvinyl butyral (PVB) interlayers, etc.

[0047] Furthermore, in this specification, the term "adhesive" refers to a layer that is adhesive at room temperature and adheres to a substrate with relatively light pressure. Therefore, even when the substrate to which the adhesive is applied is peeled off, the adhesive maintains its practical adhesive strength. On the other hand, the term "adhesive layer" refers to a layer that can bond substances together by acting as an intermediary between substances. Therefore, when the substrate to which the adhesive layer is applied is peeled off, the adhesive layer does not possess practical adhesive strength.

[0048] [Glass layer]

[0049] There are no particular limitations on the glass layer 30, and appropriate materials can be used depending on the purpose. Examples of glass layer 30, classified according to composition, include, for example, soda-lime glass, borosilicate glass, aluminosilicate glass, and quartz glass. Furthermore, examples of glass layer 30, classified according to alkali content, include alkali-free glass and low-alkali glass. The content of alkali metal components (e.g., Na₂O, K₂O, Li₂O) in the aforementioned glass is preferably 15% by weight or less, more preferably 10% by weight or less.

[0050] The thickness of the glass layer 30 is preferably 10 μm or more, taking into account the surface hardness, airtightness, and corrosion resistance of the glass. Furthermore, the glass layer 30 is expected to have membrane-like flexibility; therefore, the thickness of the glass layer 30 is preferably 300 μm or less. More preferably, the thickness of the glass layer 30 is 30 μm or more and 200 μm or less, and particularly preferably 50 μm or more and 100 μm or less.

[0051] The light transmittance of glass layer 30 at a wavelength of 550 nm is preferably 85% or higher. The refractive index of glass layer 30 at a wavelength of 550 nm is preferably 1.4 to 1.65. The density of glass layer 30 is preferably 2.3 g / cm³. 3 ~3.0g / cm 3 More preferably 2.3 g / cm³ 3 ~2.7g / cm 3 .

[0052] There are no particular limitations on the forming method of glass layer 30, and appropriate materials can be used depending on the purpose. Typically, glass layer 30 can be produced by melting a mixture containing main raw materials such as silica and alumina, defoamers such as sodium sulfate and antimony oxide, and reducing agents such as carbon at a temperature of approximately 1400°C to 1600°C, forming it into a thin sheet, and then cooling it. Examples of forming methods for glass layer 30 include, for example, the flow-through method, the fusion method, and the float method. For the purpose of thinning or improving smoothness, the glass layer formed into a sheet shape can be chemically ground using solvents such as hydrofluoric acid, as needed.

[0053] In addition, functional layers such as anti-fouling layer, anti-reflective layer, conductive layer, reflective layer, and decorative layer can be provided on the surface of glass layer 30.

[0054] [Manufacturing Method for Multilayer Structures]

[0055] Figures 4-9 This is a diagram illustrating the manufacturing process of the multilayer structure according to the first embodiment. (Refer to...) Figures 4-9 Regarding the manufacturing process of multi-layered structures, the explanation will focus particularly on the laser-based cutting process. Firstly, as... Figure 4 and Figure 5As shown, a sheet-like multilayer structure 1S is prepared by laminating a resin layer 10 and a glass layer 30 together with an adhesive layer 20. In the multilayer structure 1S, the thickness of the glass layer 30 is more than 10 μm and less than 300 μm.

[0056] A multilayer structure 1S can be obtained by laminating a resin layer 10 and a glass layer 30, which are formed into a specified shape through processes such as stamping, using an adhesive layer 20. Alternatively, the resin layer 10 and the glass layer 30 can be continuously laminated using a roll-to-roll process with the adhesive layer 20, and then single-pieceed into any size through processes such as stamping. Furthermore, the completed multilayer structure 1S can be adjusted.

[0057] In the multi-layer structure 1S, multiple product regions A are defined as the multi-layer structure 1 by single-piece processing. Figure 4 In the example, the product area A is arranged horizontally and vertically at specified intervals, but it is not limited to this. For example, product area A can be arranged in one dimension. Additionally, Figure 4 It's a floor plan. Figure 5 This is an enlarged cross-sectional view of the area near product region A in Figure 1.

[0058] Next, as Figure 6 As shown, laser L1 is irradiated from the lower 10b side of the resin layer 10 onto the outer periphery of each product region A of the multilayer structure 1S. For example, for... Figure 4 The outer periphery of each product area A shown is sequentially irradiated with laser L1 in a grid pattern. For example... Figure 7 As shown, laser L1 is irradiated, for example, until a through hole 10x is formed that penetrates the resin layer 10 and the adhesive layer 20, so that the lower surface 30b of the glass layer 30 is exposed.

[0059] When irradiated by laser L1, in the resin layer 10, for example, in Figure 4 The outer periphery of each product area A shown has through holes 10x formed in a grid pattern, with the bottom surface of the glass layer 30b as the base and the cross-sectional shape being approximately trapezoidal. The width of the widest part of the through hole 10x (the width on the side of the bottom surface 10b of the resin layer 10) is, for example, about 40 μm to 300 μm.

[0060] Irradiation with laser L1 can be performed using, for example, a carbon dioxide laser. Alternatively, a femtosecond laser can be used for irradiation with laser L1, but in cases where thermal effects may cause discoloration of the resin layer 10, a carbon dioxide laser, which is less prone to discoloration of the resin layer 10, is preferred.

[0061] Furthermore, the lower 30b side of the glass layer 30 is subject to thermal effects caused by irradiation from the laser L1. Therefore, the lower 30b exposed from the through-hole 10x of the glass layer 30 forms a molten layer 35 of a predetermined thickness in the thickness direction of the glass layer 30. For example, on the lower 30b side of the glass layer 30, in Figure 4 The outer periphery of each product area A shown will form a lattice-like molten layer 35 with a roughly semi-circular cross-sectional shape.

[0062] The molten layer 35 is formed due to thermal damage caused by laser L1 irradiation on the resin layer 10 side, resulting in residual stress. Therefore, if the thicker portion of the molten layer 35 is cut, cracks are likely to form at the cut portion. The thickness of the thickest portion of the molten layer 35 is approximately 0 μm to 25 μm, and the width of the widest portion of the molten layer 35 is the same as the width of the narrowest portion of the through hole 10x (the width on the upper 10a side of the resin layer 10).

[0063] Next, as Figure 8 As shown, laser L2 is irradiated from the upper surface 30a side of the glass layer 30 onto the outer periphery of each product region A of the multilayer structure 1S. For example, in Figure 4 The outer periphery of each product area A shown is irradiated with laser L2 at specified intervals along the grid. Figure 9 As shown, laser L2 is applied until the glass layer 30 is cut and each product region A is monolithized. Laser L2 can be applied using a femtosecond laser or a carbon dioxide laser.

[0064] When using a femtosecond laser, the diameter of a single point is approximately 0.5 μm to 2 μm, and the spacing between adjacent points is approximately 0 μm to 2 μm. That is, sometimes adjacent points overlap without any gap. When using a carbon dioxide laser, the diameter and spacing of the points are more than 10 times greater than when using a femtosecond laser. Considering the processability of glass layer 30, a femtosecond laser is preferred for this process.

[0065] like Figure 8 As shown, the cross-sectional shape of the molten layer 35 is approximately symmetrical, therefore, by irradiating a position with laser L2 closer to the product region A than the center of the molten layer 35, the thinner portion of the molten layer 35 can be cut off. The result is as follows: Figure 9 As shown, the thickness T1 of the residual molten layer 35 in product area A becomes thinner. In this process, the glass layer 30 is cut at locations where the thickness T1 of the residual molten layer 35 in each product area A after cutting is less than 3 μm. Next, by... Figure 9 The arrow portion (i.e., the location where the thickness T1 of the molten layer 35 remaining in each product area A after cutting is less than 3 μm) is irradiated with laser L2 to cut it, so that... Figure 4Each product area A shown is monolithized to create multiple multi-layered structures 1.

[0066] In addition, by adjusting in Figure 6 The irradiation conditions of laser L1 on the resin layer 10 during the process can [resistance conditions]. Figure 7 In the process shown, the thickest part of the molten layer 35 formed is controlled to be less than 3 μm. Under these conditions, even if any portion of the molten layer 35 is cut off, the thickness T1 of the cut molten layer 35 is less than 3 μm. Therefore, high efficiency in the manufacturing process can be achieved. Thus, under these conditions, by cutting off the vicinity of the thickest part of the molten layer 35, it is possible to complete the process in one step. Figure 8 arrows and Figure 9 The arrow is cut in two stages. This also enables high efficiency in the manufacturing process.

[0067] Thus, in this embodiment, the glass layer 30 is cut in such a way that the thickness of the remaining molten layer 35 in the glass layer 30 is less than 3 μm. As a result, the portion of the molten layer 35 that is prone to cracking due to heat is reduced, thereby suppressing cracking of the glass layer 30 in the product region A. That is, a multilayer structure 1 in which the glass layer 30 is less prone to cracking can be achieved.

[0068] More preferably, the glass layer 30 is cut in a manner that leaves a residual molten layer in the glass layer 30 with a thickness of less than 2 μm, and even more preferably, the glass layer 30 is cut in a manner that leaves a residual molten layer in the glass layer 30 with a thickness of less than 1 μm. This further suppresses concerns about cracking in the glass layer 30.

[0069] Furthermore, if a femtosecond laser is used to process glass layer 30, processing marks will remain on the processed side (section) of glass layer 30. These processing marks are linear grooves with the long side facing the laser irradiation direction. The spacing between adjacent grooves varies depending on the conditions, but is approximately 1 μm. In addition, the cross-section along the short side of the groove is roughly semi-circular, and the average height of the processing marks (groove depth) is approximately 0.1 μm.

[0070] <Modification 1 of the first embodiment>

[0071] In Variation 1 of the first embodiment, an example of a multilayer structure with a shape different from the outer periphery of the first embodiment is shown. Furthermore, in Variation 1 of the first embodiment, descriptions of structural portions identical to those in previously described embodiments are sometimes omitted.

[0072] Figure 10 This is a cross-sectional view of a multilayer structure according to a variation of the first embodiment 1. Figure 11 This is a plan view illustrating the multilayer structure according to the first embodiment, and is a view of the multilayer structure viewed from the top side of the glass layer.

[0073] like Figure 10 and Figure 11 As shown, the multilayer structure 1A differs from the multilayer structure 1 in that the resin layer 10 has a rectangular planar shape, while the glass layer 30 has a smaller rectangular planar shape than the resin layer 10. When viewed from above, the outer periphery of the upper surface 10a of the resin layer 10 is exposed around the side surface 30c of the glass layer 30.

[0074] However, due to the manufacturing method of the multilayer structure 1A, sometimes when viewed from above, the resin layer 10 and the glass layer 30 are the same size. Furthermore, sometimes when viewed from above, only one side of the glass layer 30 has the outer periphery of the upper surface 10a of the resin layer 10 exposed, or two or three sides of the glass layer 30 have the outer periphery of the upper surface 10a of the resin layer 10 exposed. Moreover, it is not limited to all sides 10c of the resin layer 10 being inclined surfaces; sometimes a portion of the side surface 10c is approximately perpendicular to the upper surface 10a and the lower surface 10b.

[0075] Figure 12 This is an enlarged cross-sectional view of the area near the outer periphery of the multilayer structure involved in Modification 1 of the first embodiment. For example... Figure 12 As shown, in the multilayer structure 1A, the glass layer 30 does not form a molten layer 35. Similar to the case of the multilayer structure 1, the molten layer 35 is formed during the manufacturing process of the multilayer structure 1A when the resin layer 10 is irradiated with a laser. However, the molten layer 35 is completely removed during the manufacturing process of the multilayer structure 1A, and therefore does not remain in the glass layer 30.

[0076] Furthermore, in the multilayer structure 1A, the outer periphery of the resin layer 10 protrudes horizontally from the side surface 30c of the glass layer 30. The amount P2 of the protrusion P2 from the side surface 30c of the glass layer 30 is preferably less than 10 μm. By making the protrusion P2 less than 10 μm, the thermal impact on the outer periphery of the resin layer 10 during laser cutting of the glass layer 30 can be reduced, thereby suppressing discoloration of the outer periphery of the resin layer 10. Alternatively, the protrusion P2 can also be 0 μm. That is, when viewed from above, the outer edge of the resin layer 10 can coincide with the outer edge of the glass layer 30.

[0077] Figure 13 and Figure 14 This is a diagram illustrating the manufacturing process of a multilayer structure according to a variation of the first embodiment, Example 1. (Refer to...) Figure 13 and Figure 14 The manufacturing process of multi-layer structures will be described, with a particular focus on the laser-based cutting process. First, the process described in the first embodiment will be executed... Figures 4-7 The same process as shown, after which, as Figure 13 As shown, laser L2 is irradiated from the upper surface 30a side of the glass layer 30 onto the outer periphery of each product region A. For example, in Figure 4 The outer periphery of each product area A shown is irradiated with laser L2 at predetermined intervals along the grid. Irradiation with laser L2 can be performed using a femtosecond laser or a carbon dioxide laser, but as mentioned above, a femtosecond laser is preferred.

[0078] In a variation of the first embodiment, the irradiation position of laser L2, when viewed from above, does not overlap with the bottom surface of the through-hole 10x. Therefore, the glass layer 30 can be cut at a location where there is absolutely no molten layer 35. Thus, as... Figure 14 As shown, after the glass layer 30 is cut, no molten layer 35 remains in the glass layer 30 of the product area A.

[0079] In addition, such as Figure 14 As shown, after the glass layer 30 is cut, the outer periphery of the resin layer 10 protrudes from the side surface 30c of the glass layer 30. The amount of protrusion of the outer periphery of the resin layer 10 from the side surface 30c of the glass layer 30 is as described above. Next, by... Figure 14 The arrow portion is cut by laser L2, so that... Figure 4 Each product area A shown is monolithized to create multiple multi-layered structures 1A.

[0080] As described above, the resin layer 10 and the glass layer 30 can be cut off such that the outer periphery of the resin layer 10 protrudes from the side 30c of the glass layer 30. In this case, the glass layer 30 can be cut off in such a way that the molten layer 35, which is prone to cracking due to heat, does not remain on the product area A side, thus suppressing the formation of cracks in the glass layer 30 in the product area A.

[0081] <Modification 2 of the first embodiment>

[0082] In Variation 2 of the first embodiment, an example of a multilayer structure in which the resin layer is composed of multiple layers is shown. Furthermore, in Variation 2 of the first embodiment, structural portions that are the same as those in the previously described embodiments are sometimes omitted from repeated description.

[0083] Figure 15 This is a cross-sectional view illustrating a modified example 2 of the first embodiment involving a multi-layered structure. Figure 15 As shown, in the multilayer structure 1B, the resin layer 10 is composed of multiple layers, which is consistent with the multilayer structure 1 (refer to...). Figure 1 (etc.) are different.

[0084] Starting from the adhesive layer 20 side, the resin layer 10 sequentially comprises a polarizer 12, an adhesive layer 18, and a release film 19. However, the resin layer 10 may also comprise other layers. For example, the resin layer 10 may have a phase retardation layer between the polarizer 12 and the adhesive layer 18, but it is not limited to this.

[0085] The elastic modulus of the resin layer 10 is preferably 0.1 GPa to 8.0 GPa, more preferably 0.2 GPa to 7.0 GPa, and even more preferably 0.3 GPa to 5.0 GPa. In this specification, the elastic modulus can be measured using an automatic plotter under the following conditions.

[0086] [Method for determining elastic modulus]

[0087] Measurement temperature: 23℃

[0088] Sample dimensions: 2cm wide, 15cm long

[0089] Distance between clamps: 10cm

[0090] Tensioning speed: 10 mm / min.

[0091] The polarizing plate 12 is disposed on the adhesive layer 20 side. The polarizing plate 12 has a polarizing element 121, a first protective film 122 and a second protective film 123. The first protective film 122 is disposed on the adhesive layer 20 side of the polarizing element 121, and the second protective film 123 is disposed on the adhesive layer 18 side of the polarizing element 121.

[0092] Release film 19 is disposed on the opposite side of the second protective film 123 from the polarizing element 121, separated by adhesive layer 18.

[0093] The following is a more detailed explanation of the constituent elements of the resin layer 10.

[0094] [Polarizing plate]

[0095] The thickness of the polarizing plate 12 is preferably 5 μm to 300 μm, more preferably 10 μm to 250 μm, even more preferably 25 μm to 200 μm, and particularly preferably 25 μm to 100 μm.

[0096] The elastic modulus of the polarizing plate 12 is preferably 1 GPa or higher, more preferably 1 GPa to 10 GPa, even more preferably 2 GPa to 7 GPa, and particularly preferably 2 GPa to 5 GPa. If the above range can be met, a multilayer structure 1B with excellent breakdown resistance can be obtained.

[0097] The shape of the polarizing plate 12 is not particularly limited, and an appropriate shape can be adopted depending on the purpose. For example, a square shape with a long side and a short side can be given. When the polarizing plate 12 is square, the absorption axis of the polarizing element 121 of the polarizing plate 12 is preferably substantially parallel to the long side or the short side of the polarizing plate 12. In addition, in this specification, the concept of "substantially parallel" is not limited to the strictly parallel case, but also includes the case where the angle formed by the two lines is ±10° (preferably ±5°).

[0098] [Polarization element]

[0099] The thickness of the polarizing element 121 is not particularly limited, and an appropriate thickness can be adopted depending on the purpose. The thickness of the polarizing element 121 is typically about 1 μm to 80 μm. As the polarizing element 121, a thin polarizing element can be used. In this case, the thickness of the polarizing element 121 is preferably 20 μm or less, more preferably 15 μm or less, further preferably 10 μm or less, and particularly preferably 6 μm or less.

[0100] The polarizing element 121 preferably exhibits absorption dichroism at any wavelength from 380 nm to 780 nm. The transmittance of the polarizing element is preferably 40.0% or more, more preferably 41.0% or more, even more preferably 42.0% or more, and particularly preferably 43.0% or more. The degree of polarization of the polarizing element 121 is preferably 99.8% or more, more preferably 99.9% or more, and even more preferably 99.95% or more.

[0101] The polarizing element 121 is preferably an iodine-based polarizing element. More specifically, the polarizing element can be made of a polyvinyl alcohol-based resin (hereinafter referred to as "PVA-based resin") film containing iodine.

[0102] There are no particular limitations on the PVA-based resins used to form PVA-based resin films. Appropriate resins can be used depending on the purpose. Examples include polyvinyl alcohol and ethylene-vinyl alcohol copolymers.

[0103] Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. Ethylene-vinyl alcohol copolymer is obtained by saponifying ethylene-vinyl acetate copolymer. The degree of saponification of PVA-based resins is typically 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. The degree of saponification is determined according to JIS K 6726-1994. By using PVA-based resins with such a degree of saponification, polarizing elements with excellent durability are obtained. However, there is a concern that gelation may occur if the saponification is too high.

[0104] The average degree of polymerization of PVA-based resins is not particularly limited and can be appropriately selected according to the purpose. The average degree of polymerization of PVA-based resins is, for example, 1000 to 10000, preferably 1200 to 5000, and more preferably 1500 to 4500. In addition, the average degree of polymerization is obtained according to JIS K 6726-1994.

[0105] Examples of manufacturing methods for the polarization element 121 include (I) stretching and dyeing a PVA-based resin film monomer; and (II) stretching and dyeing a laminate (i) having a resin substrate and a polyvinyl alcohol-based resin layer. Method (I) is a conventional method well known in the art, and therefore a detailed description is omitted.

[0106] Method (II) preferably includes the steps of stretching and dyeing a laminate (i) having a resin substrate and a polyvinyl alcohol-based resin layer formed on one side of the resin substrate, and fabricating a polarizing element on the resin substrate. The laminate (i) is formed by coating and drying a coating liquid containing a polyvinyl alcohol-based resin onto the resin substrate. Alternatively, the laminate (i) can be formed by transferring the polyvinyl alcohol-based resin layer onto the resin substrate. Details of the above-described manufacturing method (II) are described, for example, in Japanese Patent Application Publication No. 2012-73580, which is incorporated herein by reference.

[0107] [First and second protective films]

[0108] There are no particular limitations on the first protective film 122 and the second protective film 123, and appropriate resin films can be used depending on the purpose. Examples of materials forming the first protective film 122 and the second protective film 123 include, for example, polyester resins such as polyethylene terephthalate (PET), cellulose resins such as triacetyl cellulose (TAC), cyclic olefin resins such as norbornene resins, olefin resins such as polyethylene and polypropylene, and (meth)acrylic resins. Among these, polyethylene terephthalate (PET) is preferred. Furthermore, the term "(meth)acrylic resin" refers to acrylic resins and / or methacrylic resins.

[0109] As a (meth)acrylic resin, for example, a (meth)acrylic resin having a glutarimide structure is used. (Meth)acrylic resins having a glutarimide structure (hereinafter also referred to as glutarimide resins) are described, for example, in Japanese Patent Application Publication Nos. 2006-309033, 2006-317560, 2006-328329, 2006-328334, 2006-337491, 2006-337492, 2006-337493, 2006-337569, 2007-009182, 2009-161744, and 2010-284840. These descriptions are incorporated herein by reference.

[0110] The first protective film 122 and the second protective film 123 can be laminated with the polarizing element 121 using any suitable adhesive layer. The resin substrate used in manufacturing the polarizing element 121 is peeled off before or after the lamination of the first protective film 122 and the second protective film 123 with the polarizing element 121.

[0111] The thickness of the first protective film 122 and the second protective film 123 is preferably 4 μm to 250 μm, more preferably 5 μm to 150 μm, even more preferably 10 μm to 100 μm, and particularly preferably 10 μm to 50 μm.

[0112] The elastic modulus of the first protective film 122 and the second protective film 123 is 1 GPa or more, preferably 1 GPa to 10 GPa, more preferably 1.8 GPa to 7 GPa, and even more preferably 2 GPa to 5 GPa. If the above ranges are met, a multilayer structure 1B with excellent breakdown resistance can be obtained.

[0113] [Adhesive layer]

[0114] The adhesive layer 18 can be formed from any suitable adhesive. For example, adhesives based on polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorinated polymers, and rubber polymers are used. Acrylic adhesives are preferred. This is because acrylic adhesives exhibit excellent optical transparency, moderate wetting, agglomeration, and tackiness, and excellent weather resistance and heat resistance. Acrylic adhesives formed from acrylic polymers with a carbon number of 4 to 12 are particularly preferred.

[0115] The thickness of the adhesive layer 18 is preferably 1 μm to 100 μm, more preferably 3 μm to 80 μm, and even more preferably 3 μm to 50 μm. If the above range can be met, when the multilayer structure 1B is attached to optical elements such as liquid crystal cells to make an optical laminate, an optical laminate with excellent flexibility and excellent breakdown resistance can be obtained.

[0116] [Release membrane]

[0117] The release film 19 can be formed from resins such as polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP). The thickness of the release film 19 is preferably 5 μm to 125 μm, more preferably 20 μm to 75 μm, and even more preferably 30 μm to 50 μm. The release film 19 is peeled off at the interface with the adhesive layer 18 before the multilayer structure 1B is adhered to optical elements such as a liquid crystal cell.

[0118] Thus, in the multilayer structure, the resin layer 10 can consist of a single layer or multiple layers. In either case, by cutting the glass layer 30 in such a way that the thickness of the remaining molten layer 35 in the glass layer 30 is less than 3 μm, it is possible to suppress the formation of cracks in the glass layer 30. Even when the resin layer 10 consists of multiple layers, the cutting method using a laser is the same as in the first embodiment, etc.

[0119] Furthermore, in the multilayer structure 1A of the first embodiment, the same laminated structure as the resin layer of the multilayer structure 1B can be used.

[0120] [Example 1]

[0121] In Example 1, using Figures 4-9 The manufacturing process shown Figure 15 The structure shown is a multilayer structure. The glass layer was cut using a femtosecond laser (output: approximately 40W) to achieve a molten layer thickness of less than 3 μm. Furthermore, the amount of glass layer protruding from the side of the resin layer and the probability of crack formation in the glass layer were investigated. Additionally, 30 samples were prepared, and all samples were measured.

[0122] In the multilayer structure fabricated in Example 1, the glass layer is made of alkali-free glass with a thickness of approximately 100 μm. The adhesive layer is made of UV-curable epoxy adhesive with a thickness of approximately 1.5 μm. The first protective film is made of acrylic resin with a thickness of approximately 40 μm. The polarizing element is made of iodine-containing polyvinyl alcohol resin with a thickness of approximately 5 μm. The second protective film is made of acrylic resin with a thickness of approximately 40 μm. The adhesive layer is made of acrylic polymer with a thickness of approximately 30 μm. The release film is made of polyethylene terephthalate (PET) with a thickness of approximately 38 μm.

[0123] [Comparative Example 1]

[0124] In Comparative Example 1, a multilayer structure with the same layer structure as in Example 1 was fabricated using the same manufacturing process as in Example 1. However, the glass layer was cut using a femtosecond laser (output: approximately 40W) to make the thickness of the molten layer greater than 10 μm. The number of samples and the measurements were the same as in Example 1.

[0125] [Comparative Example 2]

[0126] In Comparative Example 2, a multilayer structure with the same layer structure as in Example 1 was fabricated using the same manufacturing process as in Example 1. However, the glass layer was cut using a femtosecond laser (output: approximately 40W) to ensure that the thickness of the molten layer was greater than 5 μm and less than 9 μm. The number of samples and the measurements were the same as in Example 1.

[0127] [Example 2]

[0128] In Example 2, the same manufacturing process as in Example 1 is used. Figure 1 The structure shown is a multilayer structure. Glass layers were cut using a femtosecond laser (output: approximately 40W) to ensure the thickness of the molten layer was less than 3 μm. The number of samples and measurements were the same as in Example 1.

[0129] In the multilayer structure fabricated in Example 2, the glass layer is made of alkali-free glass with a thickness of approximately 100 μm. The adhesive layer is made of UV-curable epoxy adhesive with a thickness of approximately 1.5 μm. The resin layer is made of polyethylene terephthalate resin with a thickness of approximately 150 μm.

[0130] [Comparative Example 3]

[0131] In Comparative Example 3, a multilayer structure with the same layer structure as in Example 2 was fabricated using the same manufacturing process as in Example 1. However, the glass layer was cut using a femtosecond laser (output: approximately 40W) to make the thickness of the molten layer greater than 10 μm. The number of samples and the measurements were the same as in Example 1.

[0132] Table 1 summarizes the results of Example 1, Example 2, and Comparative Examples 1-3.

[0133] [Table 1]

[0134] Example 1 Figure 15 <3μm <15μm 0％ Comparative Example 1 Figure 15 ≥10μm ≥20μm 100％ Comparative Example 2 Figure 15 5~9μm 15~20μm 50％ Example 2 Figure 1 <3μm <15μm 0％ Comparative Example 3 Figure 1 ≥10μm ≥20μm 100％

[0135] According to Table 1, when the glass layer is cut with a molten layer thickness of less than 3 μm, as in Examples 1 and 2, the amount of glass layer protruding from the side of the resin layer is less than 15 μm, and the probability of the glass layer cracking is 0%.

[0136] In contrast, as seen in Comparative Examples 1-3, when the thickness of the molten layer exceeds 3 μm, the amount of glass protruding from the side of the resin layer also increases, and the probability of cracks forming in the glass layer also increases. In particular, when the thickness of the molten layer is 10 μm or more, it is certain that cracks will form in the glass layer.

[0137] As described above, by cutting the glass layer in a manner that reduces the thickness of the remaining molten layer in the glass layer to less than 3 μm, it is possible to suppress the formation of cracks in the glass layer. Furthermore, the amount of glass layer protruding from the side of the resin layer is preferably less than 15 μm.

[0138] The preferred embodiments have been described in detail above, but are not limited to the embodiments described above. Various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims.

[0139] This international application claims priority based on Japanese Patent Application No. 2020-189244, filed on November 13, 2020, and incorporates the entire contents of Japanese Patent Application No. 2020-189244 in this international application.

[0140] Symbol Explanation

[0141] 1. Multi-layer structure of 1A, 1B, and 1S

[0142] 10 resin layers

[0143] 10a, 30a

[0144] Below 10b and 30b

[0145] 10c, 30c side view

[0146] 10x Through Hole

[0147] 12 polarizing plates

[0148] 18 adhesive layers

[0149] 19 Release membrane

[0150] 20 adhesive layers

[0151] 30 glass layers

[0152] 35 Melting Layer

[0153] 121 polarization element

[0154] 122 First protective film

[0155] 123 Second protective film

Claims

1. A multi-layered structure, comprising: Resin layer; A glass layer is laminated onto the resin layer using an adhesive layer; and A molten layer, defined by the thermally destructive region of the outer periphery of the glass layer, is formed on the adhesive layer side of the outer periphery of the glass layer and has residual stress. The thickness of the glass layer is between 10 μm and 300 μm. The thickness of the molten layer is less than 3 μm. The outer periphery of the glass layer protrudes from the side of the resin layer. The outer periphery of the glass layer protrudes less than 15 μm from the side of the resin layer.

2. The multi-layer structure according to claim 1, wherein, The outer periphery of the resin layer protrudes from the side of the glass layer. The outer periphery of the resin layer protrudes less than 10 μm from the side of the glass layer.

3. The multi-layer structure according to claim 2, wherein, The molten layer is exposed on the adhesive layer side of the glass layer and on the side surface of the glass layer.

4. The multilayer structure according to any one of claims 1 to 3, wherein, The side surface of the resin layer is an inclined surface formed by the side surface of the resin layer and the side surface of the adhesive layer at an angle of less than 90 degrees.

5. The multilayer structure according to any one of claims 1 to 3, wherein, The resin layer consists of multiple layers.

6. The multi-layer structure according to claim 5, wherein, The multiple layers include polarizing plates with polarizing elements.

7. A method for manufacturing a multilayer structure, comprising: The process of preparing a first multilayer structure, the first multilayer structure having a resin layer and a glass layer laminated on the resin layer by an adhesive layer, and having a plurality of product areas defined in the first multilayer structure. The process of irradiating the outer periphery of each of the product regions of the first multilayer structure with a laser from the resin layer side to form through holes in the resin layer; and The process of irradiating the outer periphery of each of the product regions of the first multilayer structure with a laser from the glass layer side to cut the glass layer, and then isolating each of the product regions into individual pieces to fabricate multiple multilayer structures. The thickness of the glass layer is between 10 μm and 300 μm. In the process of forming through holes in the resin layer, a molten layer of a specified thickness is formed on the surface exposed from the through holes in the glass layer in the thickness direction of the glass layer. During the fabrication of the multiple multilayer structures, the glass layer is cut at a position where the thickness of the molten layer is less than 3 μm. The outer periphery of the glass layer protrudes from the side of the resin layer. The outer periphery of the glass layer protrudes less than 15 μm from the side of the resin layer.

8. The method for manufacturing a multi-layer structure according to claim 7, wherein, In the process of forming through holes in the resin layer, a molten layer with a thickness of less than 3 μm is formed.

9. The method for manufacturing a multilayer structure according to claim 7 or 8, wherein, A femtosecond laser is used in the process of fabricating the multiple multilayer structures.

10. The method for manufacturing a multilayer structure according to claim 7 or 8, wherein, A carbon dioxide laser is used in the process of forming through holes in the resin layer.

Images