Multilayer structure and method of manufacturing the same

Abstract

The present multilayer structure comprises a resin layer, a glass layer laminated on the resin layer with an adhesive layer in between, and a molten layer formed on the side of the adhesive layer at the outer periphery of the glass layer, wherein the thickness of the glass layer is 10㎛ or more and 300㎛ or less, and the thickness of the molten layer is less than 3㎛.

Description

Technology Field

[0001] The present invention relates to a multilayer structure and a method for manufacturing the same. Background Technology

[0002] A multilayer structure having two or more layers laminated is known. As an example, a multilayer structure in which a silver reflective layer is laminated on a thin glass layer (glass film) can be cited. The thickness of such a multilayer structure is, for example, in the range of 1.0 to 200 μm. Such a multilayer structure is obtained, for example, from a glass roll formed by the down draw method. Prior art literature

[0003] Japanese Patent Publication No. JP2013-231744 The problem to be solved

[0004] As described above, since a glass layer with a thin plate thickness is very brittle, cracks occur easily and handling is poor; therefore, a multi-layer structure has been proposed that improves handling by reinforcing one side of the glass layer by attaching a resin layer, for example.

[0005] However, in a multilayer structure in which a thin glass layer is laminated onto a resin layer, the problem of cracks easily occurring in the glass layer is not sufficiently resolved.

[0006] The present invention has been made in consideration of these points and aims to provide a multi-layer structure in which cracks are unlikely to occur in the glass layer. means of solving the problem

[0007] The present multilayer structure comprises a resin layer, a glass layer laminated on the resin layer with an adhesive layer in between, and a molten layer formed on the side of the adhesive layer at the outer periphery of the glass layer, wherein the thickness of the glass layer is 10㎛ or more and 300㎛ or less, and the thickness of the molten layer is less than 3㎛. Effects of the invention

[0008] According to the disclosed technology, a multi-layer structure in which cracks are difficult to occur in the glass layer can be provided. Brief explanation of the drawing

[0009] FIG. 1 is a cross-sectional view illustrating a multilayer structure according to a first embodiment. FIG. 2 is a bottom view illustrating a multilayer structure according to a first embodiment. FIG. 3 is a partially enlarged cross-sectional view of the area near the outer periphery of a multilayer structure according to the first embodiment. FIG. 4 is a drawing (1) illustrating a manufacturing process of a multilayer structure according to a first embodiment. FIG. 5 is a drawing (2) illustrating a manufacturing process of a multilayer structure according to a first embodiment. FIG. 6 is a drawing (3) illustrating a manufacturing process of a multilayer structure according to a first embodiment. FIG. 7 is a drawing (4) illustrating a manufacturing process of a multilayer structure according to a first embodiment. FIG. 8 is a drawing (5) illustrating a manufacturing process of a multilayer structure according to a first embodiment. FIG. 9 is a drawing (6) illustrating a manufacturing process of a multilayer structure according to a first embodiment. FIG. 10 is a cross-sectional view illustrating a multilayer structure according to Variant Example 1 of the first embodiment. FIG. 11 is a plan view illustrating a multilayer structure according to a first embodiment. FIG. 12 is a partially enlarged cross-sectional view of the area near the outer periphery of a multilayer structure according to Variant Example 1 of the first embodiment. FIG. 13 is a drawing (1) illustrating a manufacturing process of a multilayer structure according to a modified example 1 of the first embodiment. FIG. 14 is a drawing (2) illustrating a manufacturing process of a multilayer structure according to a modified example 1 of the first embodiment. FIG. 15 is a cross-sectional view illustrating a multilayer structure according to Variant Example 2 of the first embodiment. Specific details for implementing the invention

[0010] Hereinafter, embodiments for implementing the invention will be described with reference to the drawings. In each drawing, identical components are denoted by the same reference numerals, and redundant descriptions may be omitted.

[0011] <First Embodiment>

[0012] [Multilayer structure]

[0013] FIG. 1 is a cross-sectional view illustrating a multilayer structure according to a first embodiment. FIG. 2 is a bottom view illustrating a multilayer structure according to a first embodiment, which is a view of the multilayer structure seen from the lower side of the resin layer.

[0014] As shown in FIGS. 1 and 2, the multilayer structure (1) comprises a resin layer (10), an adhesive layer (20), and a glass layer (30). The resin layer (10) has an upper surface (10a), a lower surface (10b), and a side surface (10c). The glass layer (30) has an upper surface (30a), a lower surface (30b), and a side surface (30c). In the multilayer structure (1), the glass layer (30) is laminated on the upper surface (10a) of the resin layer (10) with the adhesive layer (20) in between. That is, the adhesive layer (20) bonds the upper surface (10a) of the resin layer (10) and the lower surface (30b) of the glass layer (30).

[0015] The planar shape of the multilayer structure (1) (the shape viewed from the normal direction of the upper surface (30a) of the glass layer (30)) is, for example, a square shape. However, it is not limited to this, and the planar shape of the multilayer structure (1) can be circular, elliptical, a combination thereof, or other suitable shapes. Since the multilayer structure (1) is flexible, it can be easily attached to a curved surface.

[0016] In this embodiment, as an example, the planar shape of the multilayer structure (1) is made square. Specifically, in this embodiment, as an example, the planar shape of the resin layer (10) is square, and the planar shape of the glass layer (30) is a square shape larger than that of the resin layer (10). In addition, the side surface (10c) of the resin layer (10) is an inclined surface in which the angle formed with the upper surface (10a) of the resin layer (10) is less than 90°. That is, the cross-sectional shape of the resin layer (10) is a trapezoidal shape. In addition, the cross-sectional shape of the glass layer (30) is square. When viewed from the bottom, the outer periphery of the lower surface (30b) of the glass layer (30) is exposed around the side surface (10c) of the resin layer (10).

[0017] However, depending on the manufacturing method of the multi-layer structure (1), there may be cases where the resin layer (10) and the glass layer (30) are of the same size when viewed from the bottom. Also, when viewed from the bottom, the outer periphery of the lower surface (30b) of the glass layer (30) may be exposed only on one side of the resin layer (10), or the outer periphery of the lower surface (30b) of the glass layer (30) may be exposed on two or three sides of the resin layer (10). Furthermore, it is not limited to all sides (10c) of the resin layer (10) being inclined surfaces, and there may be cases where some sides (10c) are approximately perpendicular to the upper surface (10a) or the lower surface (10b).

[0018] FIG. 3 is a partial enlarged cross-sectional view of the area near the outer periphery of a multilayer structure according to the first embodiment. As shown in FIG. 3, a molten layer (35) may be formed on the adhesive layer (20) side of the outer periphery of the glass layer (30). The molten layer (35) may be formed in an annular shape over the entire 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.

[0019] The thickness (T1) of the molten layer (35) is the value of the thickest part of the molten layer (35) when the thickness of the molten layer (35) is measured in the vertical direction of the lower surface (30b) with respect to the lower surface (30b) of the glass layer (30). The thickness (T1) of the molten layer (35) does 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 observing with a microscope. In addition, the thickness (T1) of the molten layer (35) can also be measured using the Senarmont method.

[0020] Meanwhile, the thickness (T1) of the molten layer (35) is less than 3㎛, but it may be 0㎛. That is, the molten layer (35) may not exist. The molten layer (35) is a layer formed when laser light is irradiated onto the resin layer (10) during the manufacturing process of the multilayer structure (1). However, the molten layer (35) may be completely removed during the manufacturing process of the multilayer structure (1), in which case the thickness (T1) of the molten layer (35) becomes 0㎛. The manufacturing process of the multilayer structure (1) will be described later.

[0021] Additionally, in the multilayer structure (1), the outer periphery of the glass layer (30) protrudes horizontally from the upper portion of the side (10c) of the resin layer (10). It is preferable that the amount of protrusion (P1) from the upper portion of the side (10c) of the resin layer (10) to the outer periphery of the glass layer (30) is less than 15 μm. By making the amount of protrusion (P1) less than 15 μm, the thickness (T1) of the molten layer (35) can be made thinner. On the other hand, it does not matter if the amount of protrusion (P1) is 0 μm. That is, when viewed in a planar view, the outer edge of the resin layer (10) and the outer edge of the glass layer (30) may not coincide.

[0022] Here, the materials, etc. of each part of the multilayer structure (1) are described.

[0023] [Resin layer]

[0024] The resin layer (10) is a layer that serves as a substrate on which a glass layer (30), etc., is laminated, and has flexibility. The resin layer (10) is composed of one or more layers. When the resin layer (10) is composed of more than one layer, it is preferable to laminate them by interposing an adhesive layer having an adhesive function. The total thickness of the resin layer (10) may be 20 μm or more and 1000 μm or less from the perspective of flexibility, preferably 25 μm or more and 500 μm or less, and more preferably in the range of 50 μm or more and 200 μm or less. When the resin layer (10) is composed of a single layer, the thickness of the resin layer (10) may be, for example, in the range of 30 μm or more and 50 μm or less.

[0025] The material of the resin layer (10) may include, for example, a polyester resin such as a polyethylene terephthalate resin or a polyethylene naphthalate resin, a cycloolefin resin such as a norbornene resin, a polyethersulfone resin, a polycarbonate resin, an acrylic resin, a polyolefin resin, a polyimide resin, a polyamide resin, a polyamideamide resin, a polyarylate resin, a polysulfone resin, a polyetherimide resin, a cellulose resin, a urethane resin, etc.

[0026] [Adhesive layer]

[0027] Any suitable adhesive is used as the adhesive layer (20). The thickness of the adhesive layer (20) is, for example, 0.5 μm or more and 25 μm or less. As the adhesive layer (20), for example, an acrylic adhesive, a silicone adhesive, a rubber adhesive, a UV-curable acrylic adhesive, a UV-curable epoxy adhesive, a thermosetting epoxy adhesive, a thermosetting melamine adhesive, a thermosetting phenolic adhesive, an ethylene vinyl acetate (EVA) interlayer, a polyvinyl butyral (PVB) interlayer, etc. may be used.

[0028] Meanwhile, in this specification, the term "adhesive" refers to a layer that has adhesive properties at room temperature and adheres to a substrate under light pressure. Therefore, even when the substrate attached to the adhesive is peeled off, the adhesive maintains practical adhesive strength. Meanwhile, the term "adhesive" refers to a layer that binds materials by being interposed between them. Therefore, when the substrate attached to the adhesive is peeled off, the adhesive does not have practical adhesive strength.

[0029] [Glass layer]

[0030] There are no particular restrictions on the glass layer (30), and a suitable one can be selected depending on the purpose. According to classification by composition, the glass layer (30) may be, for example, soda-lime glass, boric acid glass, aluminosilicate glass, quartz glass, etc. And according to classification by alkali component, alkali-free glass and low-alkali glass may be, etc. The content of the alkali metal component (e.g., Na2O, K2O, Li2O) of the glass is preferably 15% by weight or less, and more preferably 10% by weight or less.

[0031] The thickness of the glass layer (30) is preferably 10 μm or more when considering the surface hardness, airtightness, and corrosion resistance of the glass. Also, since the glass layer (30) is preferably flexible like a film, 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.

[0032] The light transmittance of the glass layer (30) at a wavelength of 550 nm is preferably 85% or higher. The refractive index of the glass layer (30) at a wavelength of 550 nm is preferably 1.4 to 1.65. The density of the glass layer (30) is preferably 2.3 g / cm³ to 3.0 g / cm³, and more preferably 2.3 g / cm³ to 2.7 g / cm³.

[0033] There are no specific restrictions on the method of forming the glass layer (30), and an appropriate method may be selected depending on the purpose. Typically, the glass layer (30) can be produced by melting a mixture containing a main raw material such as silica or alumina, an antifoaming agent such as sodium sulfate or antimony oxide, and a reducing agent such as carbon at a temperature of about 1400°C to 1600°C, forming it into a thin plate shape, and then cooling it. Examples of methods for forming the glass layer (30) include the slot down draw method, the fusion method, and the floating method. The glass layer formed into a plate shape by these methods may be chemically polished with a solvent such as hydrofluoric acid as needed for purposes such as thinning or increasing smoothness.

[0034] Meanwhile, the surface of the glass layer (30) may be provided with functional layers such as an anti-fouling layer, an anti-reflection layer, a conductive layer, a reflective layer, a decorative additional layer, etc.

[0035] [Method for manufacturing a multilayer structure]

[0036] FIGS. 4 to 9 are drawings illustrating a manufacturing process of a multilayer structure according to a first embodiment. With reference to FIGS. 4 to 9, the manufacturing process of the multilayer structure will be explained, focusing particularly on the cutting process using a laser. First, as shown in FIGS. 4 and 5, a sheet-shaped multilayer structure (1S) is prepared by laminating a resin layer (10) and a glass layer (30) with an adhesive layer (20) in between. In the multilayer structure (1S), the thickness of the glass layer (30) is 10 μm or more and 300 μm or less.

[0037] A multilayer structure (1S) is obtained by laminating a resin layer (10) and a glass layer (30), formed into a predetermined shape by press processing or the like, with an adhesive layer (20) in between. Alternatively, the resin layer (10) and the glass layer (30) may be continuously laminated using a roll-to-roll process with an adhesive layer (20) in between, and then individually cut into pieces of any size by press processing or the like. In addition, a multilayer structure (1S) that has already been completed may be procured.

[0038] The multilayer structure (1S) is divided into multiple product areas (A) that become the multilayer structure (1) by individual slicing. In the example of FIG. 4, the product areas (A) are arranged vertically and horizontally at predetermined intervals, but are not limited thereto. For example, the product areas (A) may be arranged in one dimension. Meanwhile, FIG. 4 is a plan view, and FIG. 5 is a partial enlarged cross-sectional view showing the vicinity of one product area (A).

[0039] Next, as shown in FIG. 6, a laser beam (L1) is irradiated onto the outer periphery of each product area (A) of the multilayer structure (1S) from the lower surface (10b) of the resin layer (1). For example, the laser beam (L1) is irradiated sequentially in a grid shape onto the outer periphery of each product area (A) as shown in FIG. 4. As shown in FIG. 7, the laser beam (L1) is irradiated until the lower surface (30b) of the glass layer (30) is exposed, forming a through hole (10x) that penetrates, for example, the resin layer (10) and the adhesive layer (20).

[0040] By irradiating with laser light (L1), through holes (10x) having a cross-sectional shape approximately trapezoidal are formed in the resin layer (10), for example, with the lower surface (30b) of the glass layer (30) serving as the bottom surface, in a grid shape on the outer periphery of each product area (A) shown in FIG. 4. The width of the widest part of the through holes (10x) (the width on the lower surface (10b) side of the resin layer (10)) is, for example, about 40㎛ to 300㎛.

[0041] For irradiation of the laser light (L1), for example, a carbon dioxide laser can be used. Additionally, a femtosecond laser can be used for irradiation of the laser light (L1), but if discoloration of the resin layer (10) is a problem due to the influence of heat, it is preferable to use a carbon dioxide laser, which is less likely to cause discoloration of the resin layer (10).

[0042] Additionally, the lower surface (30b) of the glass layer (30) is affected by heat generated by irradiation of laser light (L1). Thus, a molten layer (35) of a predetermined thickness is formed in the thickness direction of the glass layer (30) from the lower surface (30b) exposed within the through hole (10x) in the glass layer (30). For example, on the lower surface (30b) of the glass layer (30), a molten layer (35) having a cross-sectional shape of approximately a semicircle is formed in a grid shape on the outer periphery of each product area (A) shown in FIG. 4.

[0043] The molten layer (35) is a layer formed by thermal damage caused by laser light (L1) irradiation from the resin layer (10), and residual stress is generated. Thus, if the thick part of the molten layer (35) is cut, cracks are likely to form in the cut part. The thickness of the thickest part of the molten layer (35) is about 0㎛ to 25㎛, and the width of the widest part of the molten layer (35) is about the same as the width of the narrowest part of the through hole (10x) (the width of the upper surface (10a) of the resin layer (10)).

[0044] Next, as shown in FIG. 8, a laser beam (L2) is irradiated from the upper surface (30a) of the glass layer (30) to the outer periphery of each product region (A) of the multilayer structure (1S). For example, the laser beam (L2) is irradiated in a dot shape with a predetermined interval along a grid to the outer periphery of each product region (A) shown in FIG. 4. As shown in FIG. 9, the laser beam (L2) is irradiated until the glass layer (30) is cut and each product region (A) is individually fragmented. A femtosecond laser, a carbon dioxide laser, etc., can be used for the irradiation of the laser beam (L2).

[0045] When using a femtosecond laser, the diameter of a single dot is approximately 0.5㎛ to 2㎛, and the spacing between adjacent dots is approximately 0㎛ to 2㎛. That is, there are cases where adjacent dots are repeated and there is no gap. When using a carbon dioxide laser, the diameter and spacing of the dots are more than 10 times greater than when using a femtosecond laser. Considering the processability of the glass layer (30), it is preferable to use a femtosecond laser in this process.

[0046] As shown in FIG. 8, since the cross-sectional shape of the molten layer (35) is nearly left-right symmetrical, a thin portion of the molten layer (35) can be cut by irradiating a laser light (L2) at a position close to the product area (A) from the center of the molten layer (35). As a result, as shown in FIG. 9, the thickness (T1) of the molten layer (35) remaining in the product area (A) is reduced. In this process, the glass layer (30) is cut at a position where the thickness (T1) of the molten layer (35) remaining in each product area (A) after cutting becomes less than 3 μm. Subsequently, by irradiating a laser light (L2) at the portion indicated by the arrow in FIG. 9 (i.e., the position where the thickness (T1) of the molten layer (35) remaining in each product area (A) after cutting becomes less than 3 μm) and cutting, each product area (A) shown in FIG. 4 is individually fragmented to produce a plurality of multilayer structures (1).

[0047] Meanwhile, in the process of FIG. 6, by adjusting the irradiation conditions of the laser light (L1) to be irradiated onto the resin layer (10), it is possible to control the thickest part of the molten layer (35) formed in the process shown in FIG. 7 to be less than 3 μm. In this case, no matter which part of the molten layer (35) is cut, the thickness (T1) of the molten layer (35) after cutting is less than 3 μm. Therefore, the manufacturing process can be made more efficient. In addition, in this case, by cutting near the thickest part of the molten layer (35), the cutting that was performed twice at the arrowed part of FIG. 8 and the arrowed part of FIG. 9 can be reduced to one time. In this respect, the manufacturing process can also be made more efficient.

[0048] In this way, in the present embodiment, the glass layer (30) is cut so that the thickness of the molten layer (35) remaining 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 preventing cracks from forming in the glass layer (30) of the product area (A). That is, a multi-layer structure (1) in which cracks do not easily occur in the glass layer (30) can be realized.

[0049] It is more preferable to cut the glass layer (30) so that the thickness of the molten layer remaining in the glass layer (30) is less than 2㎛, and it is even more preferable to cut the glass layer (30) so that the thickness of the molten layer remaining in the glass layer (30) is less than 1㎛. By doing so, the risk of cracks occurring in the glass layer (30) can be further suppressed.

[0050] Meanwhile, when the glass layer (30) is processed using a femtosecond laser, a processing mark remains on the processing side (cut surface) of the glass layer (30). The processing mark is a linear groove with the laser irradiation direction in the longitudinal direction. In addition, the cross-section in the width direction of the groove is approximately semicircular, and the height of the processing mark (groove depth) is approximately 0.1 μm on average.

[0051] <Variation Example 1 of the First Embodiment>

[0052] In Variation Example 1 of the first embodiment, an example of a multi-layer structure is shown in which the shape of the outer periphery is different from that of the first embodiment. Meanwhile, in Variation Example 1 of the first embodiment, the description of the same components as those already described in the embodiment may be omitted.

[0053] FIG. 10 is a cross-sectional view illustrating a multilayer structure according to Variation Example 1 of the first embodiment. FIG. 11 is a plan view illustrating a multilayer structure according to the first embodiment, in which the multilayer structure is viewed from the upper surface of the glass layer.

[0054] As shown in FIGS. 10 and 11, unlike the multilayer structure (1A), the planar shape of the resin layer (10) of the multilayer structure (1A) is square, and the planar shape of the glass layer (30) is a square shape smaller than that of the resin layer (10). When viewed in planar view, the outer periphery of the upper surface (10a) of the resin layer (10) is exposed around the side (30c) of the glass layer (30).

[0055] However, depending on the manufacturing method of the multi-layer structure (1A), there are cases where the resin layer (10) and the glass layer (30) are of the same size when viewed in a planar view. Additionally, when viewed in a planar view, there are cases where the outer periphery of the upper surface (10a) of the resin layer (10) is exposed only on one side of the glass layer (30), or where the outer periphery of the upper surface (10a) of the resin layer (10) is exposed on two or three sides of the glass layer (30). Furthermore, it is not limited to cases where all cross-sections (10c) of the resin layer (10) are inclined surfaces, and there are cases where some side surfaces (10c) are approximately perpendicular to the upper surface (10a) and lower surface (10b).

[0056] FIG. 12 is a partial enlarged cross-sectional view of the outer periphery of a multilayer structure according to Variant Example 1 of the first embodiment. As shown in FIG. 12, in the multilayer structure (1A), a molten layer (35) is not formed in the glass layer (30). As with the case of the multilayer structure (1), the molten layer (35) is formed when laser light is irradiated onto the resin layer (10) during the manufacturing process of the multilayer structure (1A). However, since the molten layer (35) is completely removed during the manufacturing process of the multilayer structure (1A), it does not remain in the glass layer (30).

[0057] Additionally, in the multilayer structure (1A), the outer periphery of the resin layer (10) protrudes horizontally from the side (30c) of the glass layer (30). It is preferable that the amount of protrusion (P2) from the side (30c) of the glass layer (30) of the outer periphery of the resin layer (10) is less than 10 μm. By making the amount of protrusion (P2) less than 10 μm, the heat effect on the outer periphery of the resin layer (10) is reduced when cutting the glass layer (30) with laser light, thereby suppressing discoloration on the outer periphery of the resin layer (10). On the other hand, the amount of protrusion (P2) may be 0 μm. That is, when viewed in a planar view, the outer edge of the resin layer (10) and the outer edge of the glass layer (30) may not coincide.

[0058] FIGS. 13 and 14 are drawings illustrating a manufacturing process for a multilayer structure according to Variation Example 1 of the first embodiment. With reference to FIGS. 13 and 14, the manufacturing process for the multilayer structure will be described, focusing particularly on the cutting process using a laser. First, after performing a process similar to the one shown in FIGS. 4 to 7 of the first embodiment, a laser beam (L2) is irradiated from the upper surface (30a) of the glass layer (30) toward the outer periphery of each product region (A) as shown in FIG. 13. For example, the laser beam (L2) is irradiated in a dot shape with a predetermined spacing along a grid toward the outer periphery of each product region (A) shown in FIG. 4. A femtosecond laser, a carbon dioxide laser, etc., may be used for the irradiation of the laser beam (L2), but as previously mentioned, it is preferable to use a femtosecond laser.

[0059] In Variation 1 of the first embodiment, the irradiation position of the laser light (L2) when viewed in a planar view is not overlapped with the bottom surface of the through hole (10x). This allows the glass layer (30) to be cut at a location where there is no molten layer (35). Thus, as shown in FIG. 14, after cutting the glass layer (30), no molten layer (35) remains in the glass layer (30) of the product area (A).

[0060] Additionally, as shown in FIG. 14, after cutting the glass layer (30), the outer periphery of the resin layer (10) protrudes from the side (30c) of the glass layer (30). The amount of protrusion from the side (30c) of the glass layer (30) of the outer periphery of the resin layer (10) is as described above. Subsequently, by irradiating a laser light (L2) onto the arrow portion of FIG. 14 and cutting, each product area (A) shown in FIG. 4 is individually fragmented to produce a plurality of multilayer structures (1A).

[0061] In this way, the resin layer (10) and the glass layer (30) can be cut so 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 so that the molten layer (35), which is prone to cracking due to heat damage, does not remain on the product area (A), thereby suppressing the occurrence of cracks in the glass layer (30) of the product area (A).

[0062] <Variation Example 2 of the First Embodiment>

[0063] In Variation Example 2 of the first embodiment, an example of a multi-layer structure is shown in which the resin layer is composed of multiple layers. Meanwhile, in Variation Example 2 of the first embodiment, the description of the same components as those in the previously described embodiment may be omitted.

[0064] FIG. 15 is a cross-sectional view illustrating a multilayer structure according to Variant Example 2 of the first embodiment. As shown in FIG. 15, the multilayer structure (1B) differs from the multilayer structure (1, see FIG. 1, etc.) in that the resin layer (10) is composed of multiple layers.

[0065] The resin layer (10) is provided in the order of a polarizing plate (12), an adhesive layer (18), and a release film (19) starting from the adhesive layer (20). However, the resin layer (10) may have additional layers. For example, the resin layer (10) may have a phase difference layer between the polarizing plate (12) and the adhesive layer (18), but is not limited thereto.

[0066] 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. The elastic modulus in this specification can be measured using an autograph according to the following conditions.

[0067] [Method for Measuring Elasticity]

[0068] Measured temperature: 23℃

[0069] Sample size: Width 2cm, Length 15cm

[0070] Distance between scales: 10cm

[0071] Tensile speed: 10mm / min

[0072] The polarizing plate (12) is positioned on the adhesive layer (20). The polarizing plate (12) comprises a polarizer (121), a first protective film (122), and a second protective film (123). The first protective film (122) is positioned on the adhesive layer (20) side of the polarizer (121), and the second protective film (123) is positioned on the adhesive layer (18) side of the polarizer (121).

[0073] The release film (19) is positioned opposite the polarizer (121) of the second protective film (123) with the adhesive layer (18) in between.

[0074] Below, each component of the resin layer (10) is described in more detail.

[0075] [Polarizing Plate]

[0076] The thickness of the polarizing plate (12) is preferably 5㎛ to 300㎛, more preferably 10㎛ to 250㎛, even more preferably 25㎛ to 200㎛, and particularly more preferably 25㎛ to 100㎛.

[0077] The elastic modulus of the polarizing plate (12) is preferably 1 GPa or more, more preferably 1 GPa to 10 GPa, even more preferably 2 GPa to 7 GPa, and particularly more preferably 2 GPa to 5 GPa. Within this range, a multilayer structure (1B) with excellent puncture resistance can be obtained.

[0078] There are no specific restrictions on the shape of the polarizing plate (12), and an appropriate shape can be selected according to the purpose. As an example, a square shape having a long side and a short side can be given. When the polarizing plate (12) has a square shape, it is preferable that the direction of the absorption axis of the polarizer (121) of the polarizing plate (12) is approximately parallel to the long side or short side of the polarizing plate (12). Meanwhile, in this specification, the term "approximately parallel" includes not only cases where they are strictly parallel, but also cases where the angle formed by the two lines is ±10° (preferably ±5°).

[0079] [Polarizer]

[0080] The thickness of the polarizer (121) is not particularly limited, and an appropriate thickness can be selected depending on the purpose. The thickness of the polarizer (121) is typically about 1 μm to 80 μm. A thin polarizer may also be used as the polarizer (121). In this case, the thickness of the polarizer (121) is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 10 μm or less, and particularly more preferably 6 μm or less.

[0081] The polarizer (121) preferably exhibits absorption dichroism at wavelengths of 380 nm to 780 nm. The single-body transmittance of the polarizer is preferably 40.0% or more, more preferably 41.0% or more, even more preferably 42.0% or more, and particularly more preferably 43.0% or more. The polarization degree of the polarizer (121) is preferably 99.8% or more, more preferably 99.9% or more, and even more preferably 99.95% or more.

[0082] The polarizer (121) is preferably an iodine-based polarizer. More specifically, the polarizer may be composed of a polyvinyl alcohol-based resin film containing iodine (hereinafter referred to as "PVA-based resin").

[0083] The PVA-based resin used to form the PVA-based resin film is not particularly limited, and a suitable resin can be selected depending on the purpose, but examples include polyvinyl alcohol and ethylene-vinyl alcohol copolymer.

[0084] 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 the PVA-based resin is typically 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, and more preferably 99.0 mol% to 99.93 mol%. The degree of saponification can be determined in accordance with JIS K 6726-1994. By using a PVA-based resin with such a degree of saponification, a polarizer with excellent durability is obtained. If the degree of saponification is too high, there is a risk that it will become saponified.

[0085] The average degree of polymerization of the PVA-based resin is not particularly limited and can be appropriately selected according to the purpose. The average degree of polymerization of the PVA-based resin is, for example, 1000 to 10000, preferably 1200 to 5000, and more preferably 1500 to 4500. Meanwhile, the average degree of polymerization can be obtained in accordance with JIS K 6726-1994.

[0086] Methods for manufacturing the polarizer (121) include, for example, a method (I) of stretching and dyeing a PVA-based resin film, and a method (II) of stretching and dyeing a laminate (i) having a resin substrate and a polyvinyl alcohol-based resin layer. Since method (I) is a well-known and commonly used method in the art, a detailed description is omitted.

[0087] Method (II) preferably comprises a process of producing a polarizer on a resin substrate by 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. The laminate (i) may be formed by applying and drying a coating solution containing a polyvinyl alcohol-based resin onto the resin substrate. Alternatively, the laminate (i) may be formed by transferring a polyvinyl alcohol-based resin layer onto the resin substrate. The above manufacturing method (II) is described in detail, for example, in Japanese Patent Publication No. JP 2012-73580, which may be referenced herein by reference.

[0088] [1st and 2nd protective films]

[0089] The first protective film (122) and the second protective film (123) are not particularly limited, and a suitable resin film may be selected according to the purpose. For example, the forming materials of the first protective film (122) and the second protective film (123) may include polyester resins such as polyethylene terephthalate (PET), cellulose resins such as triacetylcellulose (TAC), cycloolefin resins such as norbornene resins, olefin resins such as polyethylene and polypropylene, and (meth)acrylic resins. Among these, polyethylene terephthalate (PET) is preferred. Meanwhile, "(meth)acrylic resin" refers to acrylic resin and / or methacrylic resin.

[0090] As a (meth)acrylic resin, for example, a (meth)acrylic resin having a glutalimide structure is used. A (meth)acrylic resin having a glutalimide structure (hereinafter also referred to as "glutalimide resin") is described, for example, in Japanese Patent Publications No. JP 2006-309033, JP 2006-317560, JP 2006-328329, JP 2006-328334, JP 2006-337491, JP 2006-337492, JP 2006-337493, JP 2006-337569, JP 2007-009182, JP 2009-161744, and JP 2010-284840. These descriptions may be referenced in this specification by reference.

[0091] The first protective film (122) and the second protective film (123) and the polarizer (121) may be laminated with any suitable adhesive layer in between. The resin substrate used in the production of the polarizer (121) is peeled off before or after laminating the first protective film (122) and the second protective film (123) and the polarizer (121).

[0092] The thickness of the first protective film (122) and the second protective film (123) is preferably 4㎛ to 250㎛, more preferably 5㎛ to 150㎛, even more preferably 10㎛ to 100㎛, and particularly more preferably 10㎛ to 50㎛.

[0093] 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. Within this range, a multilayer structure (1B) with excellent puncture resistance can be obtained.

[0094] [Adhesive layer]

[0095] The adhesive layer (18) can be formed by any suitable adhesive. As an adhesive, for example, an adhesive having a polymer as a base polymer such as an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine-based or rubber-based polymer is used. Preferably, an acrylic adhesive is used. This is because acrylic adhesives have excellent optical transparency and exhibit adhesive properties such as appropriate wettability, cohesiveness, and adhesion, which can result in excellent weather resistance and heat resistance. In particular, an acrylic adhesive composed of an acrylic polymer having 4 to 12 carbon atoms is preferred.

[0096] 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. Within this range, the multilayer structure (1B) is attached to an optical element such as a liquid crystal cell to produce an optical laminate, and an optical laminate with excellent flexibility and excellent puncture resistance can be obtained.

[0097] [Removable Film]

[0098] The release film (19) can be formed from a resin such as polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), etc. 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 attached to an optical element such as a liquid crystal cell.

[0099] In this way, the resin layer (10) in the multi-layer structure may be composed of a single layer or multiple layers. In either case, by cutting the glass layer (30) so that the thickness of the molten layer (35) remaining on the glass layer (30) is less than 3 μm, the occurrence of cracks in the glass layer (30) can be suppressed. Even when the resin layer (10) is composed of multiple layers, the laser cutting method is the same as in the first embodiment.

[0100] Meanwhile, in the multilayer structure (1A) according to the variation 1 of the first embodiment, a laminated structure such as the resin layer of the multilayer structure (1B) may also be selected.

[0101] [Example 1]

[0102] In Example 1, a multilayer structure having the structure shown in FIG. 15 was fabricated by the manufacturing process shown in FIG. 4 to 9. The glass layer was cut using a femtosecond laser (output: approximately 40 W) so that the thickness of the molten layer was less than 3 μm. Then, the amount of protrusion of the glass layer from the side of the resin layer and the probability of cracks occurring in the glass layer were examined. Meanwhile, 30 samples were fabricated and measurements were taken for all samples.

[0103] In the multilayer structure prepared in Example 1, alkali-free glass was used as the material for the glass layer, and the thickness was set to approximately 100 μm. UV-curable epoxy-based adhesive was used as the material for the adhesive layer, and the thickness was set to approximately 1.5 μm. Acrylic resin was used as the material for the first protective film, and the thickness was set to approximately 40 μm. Polyvinyl alcohol-based resin containing iodine was used as the material for the polarizer, and the thickness was set to approximately 5 μm. Acrylic resin was used as the material for the second protective film, and the thickness was set to approximately 40 μm. Acrylic polymer was used as the material for the adhesive layer, and the thickness was set to approximately 30 μm. Polyethylene terephthalate (PET) was used as the material for the release film, and the thickness was set to approximately 38 μm.

[0104] [Comparative Example 1]

[0105] In Comparative Example 1, a multilayer structure having the same layer structure as in Example 1 was fabricated by the same manufacturing process as in Example 1. However, the glass layer was cut using a femtosecond laser (output: approximately 40 W) so that the thickness of the molten layer was 10 μm or more. The number of samples and measurement items are the same as in Example 1.

[0106] [Comparative Example 2]

[0107] In Comparative Example 2, a multilayer structure having the same layer structure as in Example 1 was fabricated by the same manufacturing process as in Example 1. However, the glass layer was cut using a femtosecond laser (output: approximately 40 W) so that the thickness of the molten layer was 5 μm or more and less than 9 μm. The number of samples and measurement items are the same as in Example 1.

[0108] [Example 2]

[0109] In Example 2, a multilayer structure having the structure shown in Fig. 1 was fabricated by the same manufacturing process as in Example 1. The glass layer was cut using a femtosecond laser (output: about 40 W) so that the thickness of the molten layer was less than 3 μm. The number of samples and measurement items are the same as in Example 1.

[0110] In the multilayer structure prepared in Example 2, alkali-free glass was used as the material for the glass layer, and the thickness was set to about 100 μm. UV-curable epoxy-based adhesive was used as the material for the adhesive layer, and the thickness was set to about 1.5 μm. Polyethylene terephthalate-based resin was used as the material for the resin layer, and the thickness was set to about 150 μm.

[0111] [Comparative Example 3]

[0112] In Comparative Example 3, a multilayer structure having the same layer structure as in Example 2 was fabricated by the same manufacturing process as in Example 1. However, the glass layer was cut using a femtosecond laser (output: approximately 40 W) so that the thickness of the molten layer was 10 μm or more. The number of samples and measurement items are the same as in Example 1.

[0113] Table 1 summarizes the results of Example 1, Example 2, and Comparative Examples 1 to 3.

[0114]

[0115] As can be seen from Table 1, when the glass layer was cut so that the thickness of the molten layer was less than 3 μm as in Examples 1 and 2, the amount of glass layer protruding from the side of the resin layer was less than 15 μm, and the probability of cracks occurring in the glass layer was 0%. In contrast, as in Comparative Examples 1 to 3, it can be seen that as the thickness of the molten layer exceeds 3 μm, the amount of glass layer protruding from the side of the resin layer increases, and the probability of cracks occurring in the glass layer increases. In particular, it can be seen that when the thickness of the molten layer is 10 μm or more, cracks inevitably occur in the glass layer.

[0116] In this way, by cutting the glass layer so that the thickness of the molten layer remaining in the glass layer is less than 3㎛, the occurrence of cracks in the glass layer can be suppressed. In addition, it is preferable that the amount of glass layer protrusion from the side of the resin layer is less than 15㎛.

[0117] Although preferred embodiments have been described in detail above, they are not limited to the aforementioned embodiments, and various modifications and substitutions may be made to the aforementioned embodiments without departing from the scope described in the claims.

[0118] 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 into this international application. Explanation of the symbols

[0119] 1,1A,1B,1S multilayer structure 10 resin layers 10a,30a upper surface If you do 10b, 30b 10c, 30c side 10x through holes 12 polarizing plates 18 adhesive layer 19 Release film 20 adhesive layers 30 glass layers 35 molten layer 121 Polarizer 122 First protective film 123 Second protective film

Claims

Claim 1 A multilayer structure comprising a resin layer, a glass layer laminated on the resin layer with an adhesive layer in between, and a molten layer formed on the side of the adhesive layer at the outer periphery of the glass layer, wherein the thickness of the glass layer is 10㎛ or more and 300㎛ or less, the outer periphery of the glass layer protrudes from the side of the resin layer, the amount of protrusion from the side of the resin layer at the outer periphery of the glass layer is less than 15㎛, the molten layer is a molten glass layer, and the thickness of the molten layer is less than 3㎛. Claim 2 delete Claim 3 delete Claim 4 A multilayer structure according to claim 1, wherein the molten layer is exposed on the side of the glass layer toward the adhesive layer and on the side of the glass layer. Claim 5 A multilayer structure according to claim 1 or 4, wherein the side of the resin layer is an inclined surface having an angle of less than 90° with the side of the resin layer toward the adhesive layer. Claim 6 A multilayer structure according to claim 1 or 4, wherein the resin layer is composed of a plurality of layers. Claim 7 In claim 6, the plurality of layers comprises a polarizing plate having a polarizer, forming a multilayer structure. Claim 8 A method for manufacturing a multilayer structure comprising: a process of preparing a first multilayer structure divided into a plurality of product regions, the first multilayer structure including a resin layer and a glass layer laminated on the resin layer with an adhesive layer in between; a process of forming a through hole in the resin layer by irradiating a laser light from the side of the resin layer to the outer periphery of each of the product regions of the first multilayer structure, and a process of manufacturing a plurality of multilayer structures by irradiating a laser light from the side of the glass layer to the outer periphery of each of the product regions of the first multilayer structure to cut the glass layer, thereby individually slicing each of the product regions; wherein the thickness of the glass layer is 10㎛ or more and 300㎛ or less; in the process of forming a through hole in the resin layer, a molten layer of a predetermined thickness is formed in the thickness direction of the glass layer from the surface exposed into the through hole in the glass layer; and in the process of manufacturing the plurality of multilayer structures, the glass layer is cut such that the outer periphery of the glass layer protrudes from the side of the resin layer at a position where the thickness of the molten layer is less than 3㎛, and the amount of protrusion is less than 15㎛. Claim 9 A method for manufacturing a multilayer structure according to claim 8, wherein in the process of forming a through hole in the resin layer, the molten layer having a thickness of less than 3 μm is formed. Claim 10 A method for manufacturing a multilayer structure according to claim 8 or 9, wherein a femtosecond laser is used in the process of manufacturing the plurality of multilayer structures. Claim 11 A method for manufacturing a multilayer structure according to claim 8 or 9, wherein a carbon dioxide laser is used in the process of forming a through hole in the resin layer.

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