Multilayer structure and method for manufacturing the same

Abstract

To provide a multilayer laminate which hardly causes cracks on a glass layer.SOLUTION: A multilayer structure has a resin layer 10, a glass layer 30 laminated on the resin layer 10 through an adhesive layer 20, and a molten layer 35 formed on the side of the adhesive layer of an outer peripheral part of the glass layer 30, in which thickness of the glass layer 30 is 10-300 μm and thickness T1 of the molten layer 35 is less than 3 μm.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a multi-layer structure and a method for producing the same. [Background technology]

[0002] Multilayer structures in which two or more layers are laminated are known. One example is a multilayer structure in which a silver reflective layer is laminated on a thin glass layer (glass film). The thickness of this multilayer structure is, for example, in the range of 1.0 to 200 μm. This multilayer structure is obtained, for example, from a glass roll formed by a down-draw method. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-231744 Summary of the Invention [Problem to be solved by the invention]

[0004] Since the above-mentioned thin glass layer is very fragile, cracks are easily generated, and handling is poor. Therefore, for example, a multilayer structure has been proposed in which a resin layer is attached to one side of the glass layer to reinforce it and improve handling.

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

[0006] The present invention has been made in view of the above points, and has an object to provide a multi-layer structure in which cracks are less likely to occur in the glass layers. [Means for solving the problem]

[0007] The multilayer structure includes a resin layer, a glass layer laminated on the resin layer via an adhesive layer, and a glass layer formed on the adhesive layer side of the outer periphery of the glass layer. Has residual stress and a fusion layer, the thickness of the glass layer being 10 μm or more and 300 μm or less, and the thickness of the fusion layer being less than 3 μm. [Effects of the Invention]

[0008] According to the disclosed technology, it is possible to provide a multilayer structure in which cracks are less likely to occur in the glass layer. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view illustrating a multilayer structure according to a first embodiment. [Figure 2] FIG. 2 is a bottom view illustrating the multilayer structure according to the first embodiment. [Figure 3] FIG. 2 is a partially enlarged cross-sectional view of the vicinity of the outer periphery of the multilayer structure according to the first embodiment. [Figure 4] 1A to 1C are diagrams illustrating a manufacturing process of a multilayer structure according to the first embodiment (part 1). [Figure 5] 4A to 4C are diagrams (part 2) illustrating the manufacturing process of the multilayer structure according to the first embodiment. [Figure 6] 4A to 4C are views (part 3) illustrating the manufacturing process of the multilayer structure according to the first embodiment. [Figure 7] 4A to 4C are views illustrating the manufacturing process of the multilayer structure according to the first embodiment (part 4). [Figure 8] 5A to 5C are diagrams illustrating the manufacturing process of the multilayer structure according to the first embodiment. [Figure 9] FIG. 6 is a diagram (part 6) illustrating the manufacturing process of the multilayer structure according to the first embodiment. [Figure 10] FIG. 2 is a cross-sectional view illustrating a multilayer structure according to a first modified example of the first embodiment. [Figure 11] 1 is a plan view illustrating a multilayer structure according to a first embodiment. [Figure 12]FIG. 10 is a partially enlarged cross-sectional view of the vicinity of the outer periphery of a multilayer structure according to Modification 1 of the first embodiment. [Figure 13] 1A to 1C are diagrams (part 1) illustrating a manufacturing process of a multilayer structure according to Modification 1 of the first embodiment. [Figure 14] 10A to 10C are diagrams (part 2) illustrating the manufacturing process of the multilayer structure according to the first modified example of the first embodiment. [Figure 15] FIG. 10 is a cross-sectional view illustrating a multilayer structure according to a second modification of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations may be omitted.

[0011] First Embodiment [Composite structure] Fig. 1 is a cross-sectional view illustrating the multilayer structure according to the first embodiment. Fig. 2 is a bottom view illustrating the multilayer structure according to the first embodiment, as viewed from the underside of the resin layer.

[0012] As shown in FIGS. 1 and 2, the multilayer structure 1 has 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 via the adhesive layer 20. In other words, the adhesive layer 20 bonds the upper surface 10a of the resin layer 10 and the lower surface 30b of the glass layer 30 together.

[0013] The planar shape of the multilayer structure 1 (the shape when viewed from the normal direction of the upper surface 30a of the glass layer 30) is, for example, rectangular. However, this is not limited to this, and the planar shape of the multilayer structure 1 can be circular, elliptical, a combination of these, or any other appropriate shape. The multilayer structure 1 is flexible, so it can be easily attached to curved surfaces.

[0014] 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 rectangular and larger than the resin layer 10. Furthermore, the side surface 10c of the resin layer 10 is an inclined surface that forms an angle of less than 90 degrees with the top surface 10a of the resin layer 10. In other words, the cross-sectional shape of the resin layer 10 is trapezoidal. Furthermore, the cross-sectional shape of the glass layer 30 is rectangular. In bottom view, 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.

[0015] However, depending on the method for producing the multilayer structure 1, the resin layer 10 and the glass layer 30 may have the same size when viewed from the bottom. Furthermore, 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, not all of the side surfaces 10c of the resin layer 10 are necessarily inclined surfaces, and some of the side surfaces 10c may be approximately perpendicular to the upper surface 10a and the lower surface 10b.

[0016] Figure 3 is a partially enlarged cross-sectional view of the vicinity of the outer periphery of the multilayer structure according to the first embodiment. As shown in Figure 3, a melt layer 35 may be formed on the adhesive layer 20 side of the outer periphery of the glass layer 30. The melt layer 35 may also be formed in a ring shape over the entire outer periphery of the glass layer 30. The cross-sectional shape of the melt layer 35 is, for example, a fan shape. The melt 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 melt layer 35 is less than 3 µm.

[0017] 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 a direction perpendicular to the lower surface 30b of the glass layer 30, with the lower surface 30b as the reference. The thickness T1 of the molten layer 35 does not reach 3 μm regardless of the position on the side surface 30c of the glass layer 30 measured. The thickness T1 of the molten layer 35 can be measured, for example, by observation with a microscope. The thickness T1 of the molten layer 35 can also be measured using the Senarmont method.

[0018] The thickness T1 of the melt layer 35 may be 0 μm as long as it is less than 3 μm. In other words, the melt layer 35 may not be present. The melt layer 35 is a layer formed when the resin layer 10 is irradiated with laser light during the manufacturing process of the multi-layer structure 1. However, there are cases where the melt layer 35 is completely removed during the manufacturing process of the multi-layer structure 1, in which case the thickness T1 of the melt layer 35 is 0 μm. The manufacturing process of the multi-layer structure 1 will be described later.

[0019] 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 of protrusion P1 of the outer periphery of the glass layer 30 from the upper end of the side surface 10c of the resin layer 10 is preferably less than 15 μm. By setting the amount of protrusion P1 to less than 15 μm, the thickness T1 of the molten layer 35 can be made even thinner. Note that the amount of protrusion P1 may be 0 μm. In other words, the outer edge of the resin layer 10 and the outer edge of the glass layer 30 may coincide in a planar view.

[0020] Here, the materials and the like of each part of the multi-layer structure 1 will be described.

[0021] [Resin layer] The resin layer 10 is a flexible layer that serves as a base material for laminating the glass layer 30 and the like. The resin layer 10 is composed of one layer or multiple layers. When the resin layer 10 is composed of multiple layers, it is preferable to laminate them with an adhesive layer interposed therebetween. From the viewpoint of flexibility, the total thickness of the resin layer 10 may be 20 μm or more and 1000 μm or less, preferably 25 μm or more and 500 μm or less, and more preferably 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 can be, for example, 30 μm or more and 50 μm or less.

[0022] Examples of materials for the resin layer 10 include 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, polyimideamide resins, polyarylate resins, polysulfone resins, polyetherimide resins, cellulose resins, and urethane resins.

[0023] [Adhesive layer] Any appropriate adhesive can be 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. For example, the adhesive layer 20 can be made of an acrylic adhesive, a silicone adhesive, a rubber adhesive, an ultraviolet-curable acrylic adhesive, an ultraviolet-curable epoxy adhesive, a thermosetting epoxy adhesive, a thermosetting melamine adhesive, a thermosetting phenol adhesive, an ethylene vinyl acetate (EVA) interlayer, or a polyvinyl butyral (PVB) interlayer.

[0024] In this specification, a pressure-sensitive adhesive refers to a layer that has adhesive properties at room temperature and adheres to an adherend with light pressure. Therefore, even when an adherend that has been stuck to the pressure-sensitive adhesive is peeled off, the pressure-sensitive adhesive retains practical adhesive strength. On the other hand, an adhesive refers to a layer that can bond substances by being interposed between them. Therefore, when an adherend that has been stuck to the adhesive is peeled off, the adhesive no longer has practical adhesive strength.

[0025] [Glass layer] The glass layer 30 is not particularly limited, and an appropriate glass layer can be adopted depending on the purpose. The glass layer 30 can be classified by composition, for example, soda-lime glass, borate glass, aluminosilicate glass, quartz glass, etc. Furthermore, the glass layer 30 can be classified by alkali component, for example, alkali-free glass or low-alkali glass. The content of alkali metal components (e.g., Na2O, KO, Li2O) in the glass is preferably 15 wt% or less, and more preferably 10 wt% or less.

[0026] Considering the surface hardness, airtightness, and corrosion resistance of glass, the thickness of the glass layer 30 is preferably 10 μm or more. Furthermore, since it is desirable for the glass layer 30 to have flexibility like a film, the thickness of the glass layer 30 is preferably 300 μm or less. The thickness of the glass layer 30 is more preferably 30 μm to 200 μm, and particularly preferably 50 μm to 100 μm.

[0027] The light transmittance of the glass layer 30 at a wavelength of 550 nm is preferably 85% or more. 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 / cm 3 ~3.0g / cm 3 and more preferably 2.3 g / cm 3 ~2.7g / cm 3 is.

[0028] The method for forming the glass layer 30 is not particularly limited, and an appropriate method can be adopted 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 mirabilite or antimony oxide, and a reducing agent such as carbon at a temperature of approximately 1400°C to 1600°C, forming it into a thin plate, and then cooling it. Examples of methods for forming the glass layer 30 include the slot downdraw method, the fusion method, and the float method. The glass layer formed into a plate by these methods may be chemically polished with a solvent such as hydrofluoric acid, as necessary, to make it thinner or to improve smoothness.

[0029] The surface of the glass layer 30 may be provided with a functional layer such as an antifouling layer, an antireflection layer, a conductive layer, a reflective layer, or a decorative layer.

[0030] [Manufacturing method for multi-layer structure] 4 to 9 are diagrams illustrating the manufacturing process of the multilayer structure according to the first embodiment. With reference to FIGS. 4 to 9, the manufacturing process of the multilayer structure will be described, focusing in particular on the cutting process using a laser. First, as shown in FIGS. 4 and 5, a sheet-like multilayer structure 1S is prepared in which a resin layer 10 and a glass layer 30 are laminated via an adhesive layer 20. In the multilayer structure 1S, the thickness of the glass layer 30 is 10 μm or more and 300 μm or less.

[0031] The multilayer structure 1S is obtained by laminating a resin layer 10 and a glass layer 30, which have been formed into a predetermined shape by press working or the like, via an adhesive layer 20. Alternatively, the resin layer 10 and the glass layer 30 may be continuously laminated via the adhesive layer 20 using a roll-to-roll process, and then cut into pieces of any size by press working or the like. Alternatively, an already completed multilayer structure 1S may be procured.

[0032] The multilayer structure 1S has a plurality of product areas A defined therein, which will become the multilayer structure 1 when separated into individual pieces. In the example of FIG. 4, the product areas A are arranged vertically and horizontally at a predetermined interval, but this is not limited to this. For example, the product areas A may be arranged one-dimensionally. Note that FIG. 4 is a plan view, and FIG. 5 is a partially enlarged cross-sectional view illustrating the vicinity of one product area A.

[0033] Next, as shown in Fig. 6, the outer periphery of each product area A of the multilayer structure 1S is irradiated with laser light L1 from the underside 10b of the resin layer 10. For example, the outer periphery of each product area A shown in Fig. 4 is sequentially irradiated with laser light L1 in a grid pattern. As shown in Fig. 7, the laser light L1 is irradiated until, for example, through holes 10x penetrating the resin layer 10 and the adhesive layer 20 are formed and the underside 30b of the glass layer 30 is exposed.

[0034] By irradiating the resin layer 10 with the laser light L1, for example, through holes 10x having a substantially trapezoidal cross section with their bottoms facing the lower surface 30b of the glass layer 30 are formed in a grid pattern 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, approximately 40 µm to 300 µm.

[0035] For example, a carbon dioxide laser can be used to irradiate the laser light L1. Note that, although a femtosecond laser may be used to irradiate the laser light L1, if discoloration of the resin layer 10 due to the influence of heat becomes a problem, it is preferable to use a carbon dioxide laser, which is less likely to cause discoloration of the resin layer 10.

[0036] Furthermore, the lower surface 30b side of the glass layer 30 is affected by heat generated by the irradiation of the laser light L1. Therefore, a molten layer 35 having a predetermined thickness is formed in the thickness direction of the glass layer 30 from the lower surface 30b exposed in the through-hole 10x of the glass layer 30. For example, on the lower surface 30b side of the glass layer 30, the molten layer 35 having a substantially semicircular cross section is formed in a lattice pattern on the outer periphery of each product area A shown in FIG.

[0037] Melt layer 35 is a layer formed by thermal damage caused by irradiation with laser light L1 from the resin layer 10 side, and has residual stress. Therefore, when a thick portion of melt layer 35 is cut, cracks are likely to occur in the cut portion. The thickness of the thickest portion of melt layer 35 is approximately 0 μm to 25 μm, and the width of the widest portion of melt layer 35 is approximately the same as the width of the narrowest portion of through hole 10x (the width on the upper surface 10a side of resin layer 10).

[0038] Next, as shown in Fig. 8, the outer periphery of each product area A of the multilayer structure 1S is irradiated with laser light L2 from the upper surface 30a side of the glass layer 30. For example, the outer periphery of each product area A shown in Fig. 4 is irradiated with laser light L2 in the form of dots at predetermined intervals along a grid. As shown in Fig. 9, the laser light L2 is irradiated until the glass layer 30 is cut and each product area A is separated into individual pieces. A femtosecond laser or a carbon dioxide laser can be used to irradiate the laser light L2.

[0039] When a femtosecond laser is used, the diameter of each dot is approximately 0.5 μm to 2 μm, and the spacing between adjacent dots is approximately 0 μm to 2 μm. In other words, adjacent dots may overlap and there may be no spacing between them. When a carbon dioxide laser is used, the diameter and spacing of the dots are 10 times or more larger than when a femtosecond laser is used. Considering the processability of the glass layer 30, it is preferable to use a femtosecond laser in this process.

[0040] As shown in FIG. 8, the cross-sectional shape of molten layer 35 is almost symmetrical, so that thin portions of molten layer 35 can be cut by irradiating laser light L2 at a position closer to product region A than the center of molten layer 35. As a result, as shown in FIG. 9, thickness T1 of molten layer 35 remaining in product region A becomes thinner. In this process, glass layer 30 is cut at a position where thickness T1 of molten layer 35 remaining in each product region A after cutting will be less than 3 μm. Subsequently, laser light L2 is irradiated and cut at the arrow portions in FIG. 9 (i.e., positions where thickness T1 of molten layer 35 remaining in each product region A after cutting will be less than 3 μm), whereby each product region A shown in FIG. 4 is divided into individual pieces, and multiple multilayer structures 1 are produced.

[0041] By adjusting the irradiation conditions of the laser light L1 irradiated onto the resin layer 10 in the process of FIG. 6, it is also possible to control the thickness of the thickest portion of the molten layer 35 formed in the process of FIG. 7 to be less than 3 μm. In this case, regardless of which part of the molten layer 35 is cut, the thickness T1 of the molten layer 35 after cutting will be less than 3 μm. This makes it possible to improve the efficiency of the manufacturing process. Furthermore, by cutting near the thickest part of the molten layer 35, it is possible to reduce the cutting time from two times as indicated by the arrows in FIG. 8 and FIG. 9 to one time. This also makes it possible to improve the efficiency of the manufacturing process.

[0042] As described above, in this 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. This reduces the amount of cutting that is required for the molten layer 35, which is susceptible to cracking due to heat damage, and thus makes it possible to prevent cracks from occurring in the glass layer 30 in the product region A. In other words, a multilayer structure 1 in which cracks are less likely to occur in the glass layer 30 can be realized.

[0043] It is more preferable to cut the glass layer 30 so that the thickness of the molten layer remaining on the glass layer 30 is less than 2 μm, and it is even more preferable to cut the glass layer 30 so that the thickness of the molten layer remaining on the glass layer 30 is less than 1 μm. This can further reduce the risk of cracks occurring in the glass layer 30.

[0044] When the glass layer 30 is processed using a femtosecond laser, processing marks remain on the processed side surface (cut surface) of the glass layer 30. The processing marks are linear grooves with the laser irradiation direction as the longitudinal direction. The pitch between adjacent grooves varies depending on the conditions, but is approximately 1 μm. In addition, the cross section of the groove in the short direction is approximately semicircular, and the height of the processing marks (groove depth) is approximately 0.1 μm on average.

[0045] <Modification 1 of the First Embodiment> In Modification 1 of the first embodiment, an example of a multi-layer structure having a different shape of the outer periphery from that of Embodiment 1 is shown. Note that in Modification 1 of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0046] Fig. 10 is a cross-sectional view illustrating a multi-layer structure according to Modification 1 of Embodiment 1. Fig. 11 is a plan view illustrating the multi-layer structure according to Embodiment 1, as viewed from the top surface side of the glass layer.

[0047] 10 and 11 , in the multilayer structure 1A, unlike the multilayer structure 1, the resin layer 10 has a rectangular planar shape, and the glass layer 30 has a rectangular planar shape that is smaller than that of the resin layer 10. In a plan view, 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.

[0048] However, depending on the method for producing the multilayer structure 1A, the resin layer 10 and the glass layer 30 may have the same size in a planar view. Furthermore, in a planar view, the outer periphery of the upper surface 10a of the resin layer 10 may be exposed on only one side of the glass layer 30, or the outer periphery of the upper surface 10a of the resin layer 10 may be exposed on two or three sides of the glass layer 30. Furthermore, not all of the side surfaces 10c of the resin layer 10 are necessarily inclined surfaces, and some of the side surfaces 10c may be approximately perpendicular to the upper surface 10a or the lower surface 10b.

[0049] Fig. 12 is a partially enlarged cross-sectional view of the vicinity of the outer periphery of a multilayer structure according to Modification 1 of the first embodiment. As shown in Fig. 12, in multilayer structure 1A, no molten layer 35 is formed in glass layer 30. As in the case of multilayer structure 1, molten layer 35 is formed when resin layer 10 is irradiated with laser light in the manufacturing process of multilayer structure 1A. However, molten layer 35 is completely removed in the manufacturing process of multilayer structure 1A, and therefore does not remain in glass layer 30.

[0050] 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 protrusion amount P2 of the outer periphery of the resin layer 10 from the side surface 30c of the glass layer 30 is preferably less than 10 μm. By setting the protrusion amount P2 to less than 10 μm, the thermal influence on the outer periphery of the resin layer 10 when the glass layer 30 is cut with laser light is reduced, thereby preventing discoloration from occurring in the outer periphery of the resin layer 10. Note that the protrusion amount P2 may be 0 μm. In other words, the outer edge of the resin layer 10 and the outer edge of the glass layer 30 may coincide in a planar view.

[0051] 13 and 14 are diagrams illustrating the manufacturing process of a multilayer structure according to Modification 1 of the first embodiment. The manufacturing process of the multilayer structure will be described with reference to FIGS. 13 and 14, focusing particularly on the cutting process using a laser. First, after performing the same processes as those shown in FIGS. 4 to 7 of the first embodiment, as shown in FIG. 13, laser light L2 is irradiated onto the outer periphery of each product area A from the upper surface 30a of the glass layer 30. For example, the laser light L2 is irradiated onto the outer periphery of each product area A shown in FIG. 4 in a dot pattern at predetermined intervals along a lattice. A femtosecond laser or a carbon dioxide laser can be used to irradiate the laser light L2, but as mentioned above, it is preferable to use a femtosecond laser.

[0052] In Modification 1 of the first embodiment, the irradiation position of the laser beam L2 does not overlap the bottom surface of the through hole 10x in a plan view. This allows the glass layer 30 to be cut at a position where there is no molten layer 35. Therefore, as shown in FIG. 14 , after the glass layer 30 is cut, no molten layer 35 remains in the glass layer 30 in the product area A.

[0053] 14, 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. Subsequently, by irradiating the portions indicated by the arrows in FIG. 14 with laser light L2 and cutting them, each product area A shown in FIG. 4 is separated into individual pieces, and a plurality of multilayer structures 1A are produced.

[0054] In this manner, the resin layer 10 and the glass layer 30 may be cut so that the outer periphery of the resin layer 10 protrudes from the side surface 30c of the glass layer 30. In this case, the glass layer 30 can be cut so that the molten layer 35, which is easily damaged by heat and cracked, does not remain on the product area A side, thereby preventing cracks from occurring in the glass layer 30 in the product area A.

[0055] <Modification 2 of the First Embodiment> In Modification 2 of the first embodiment, an example of a multi-layer structure in which the resin layer is composed of multiple layers is shown. Note that in Modification 2 of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0056] Fig. 15 is a cross-sectional view illustrating a multi-layer structure according to Modification 2 of Embodiment 1. As shown in Fig. 15, multi-layer structure 1B differs from multi-layer structure 1 (see Fig. 1, etc.) in that resin layer 10 is composed of multiple layers.

[0057] The resin layer 10 includes, in this order from the adhesive layer 20 side, a polarizing plate 12, a pressure-sensitive adhesive layer 18, and a release film 19. However, the resin layer 10 may further include other layers. For example, the resin layer 10 may include a retardation layer between the polarizing plate 12 and the pressure-sensitive adhesive layer 18, but is not limited to this.

[0058] 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 autograph under the following conditions.

[0059] [Elastic modulus measurement method] Measurement temperature: 23℃ Sample size: width 2cm, length 15cm Distance between chucks: 10cm Tensile speed: 10 mm / min.

[0060] The polarizing plate 12 is disposed on the adhesive layer 20 side. The polarizing plate 12 has a polarizer 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 polarizer 121, and the second protective film 123 is disposed on the pressure-sensitive adhesive layer 18 side of the polarizer 121.

[0061] Release film 19 is disposed on the opposite side of second protective film 123 from polarizer 121, with pressure-sensitive adhesive layer 18 interposed therebetween.

[0062] Each component of the resin layer 10 will be described in more detail below.

[0063] [Polarizing plate] The thickness of the polarizing plate 12 is preferably 5 μm to 300 μm, more preferably 10 μm to 250 μm, still more preferably 25 μm to 200 μm, and particularly preferably 25 μm to 100 μm.

[0064] The modulus of elasticity of the polarizing plate 12 is preferably 1 GPa or more, more preferably 1 GPa to 10 GPa, still more preferably 2 GPa to 7 GPa, and particularly preferably 2 GPa to 5 GPa. Within this range, a multilayer structure 1B having excellent puncture resistance can be obtained.

[0065] The shape of the polarizing plate 12 is not particularly limited and can be any appropriate shape depending on the purpose, but one example is a rectangular shape having long and short sides. When the polarizing plate 12 has a rectangular shape, it is preferable that the absorption axis direction of the polarizer 121 of the polarizing plate 12 is approximately parallel to the long or short side of the polarizing plate 12. In this specification, the term "approximately parallel" not only refers to being strictly parallel, but also encompasses a case where the angle between the two lines is within ±10° (preferably ±5°).

[0066] [Polarizer] There are no particular limitations on the thickness of polarizer 121, and an appropriate thickness can be adopted depending on the purpose. The thickness of polarizer 121 is typically about 1 μm to 80 μm. A thin polarizer may be used as polarizer 121, and in this case, the thickness of polarizer 121 is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, and particularly preferably 6 μm or less.

[0067] The polarizer 121 preferably exhibits absorptive dichroism at any wavelength between 380 nm and 780 nm. The single 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 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.

[0068] The polarizer 121 is preferably an iodine-based polarizer. More specifically, the polarizer can be made of a polyvinyl alcohol-based resin (hereinafter referred to as a "PVA-based resin") film containing iodine.

[0069] The PVA resin that forms the PVA resin film is not particularly limited, and an appropriate resin can be used depending on the purpose, but examples thereof include polyvinyl alcohol and ethylene-vinyl alcohol copolymer.

[0070] Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. Ethylene-vinyl alcohol copolymer is obtained by saponifying ethylene-vinyl acetate copolymer. The saponification degree of the PVA resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, and more preferably 99.0 mol% to 99.93 mol%. The saponification degree is determined in accordance with JIS K 6726-1994. By using a PVA resin with such a saponification degree, a polarizer with excellent durability can be obtained. If the saponification degree is too high, gelation may occur.

[0071] The average degree of polymerization of the PVA-based resin is not particularly limited and can be appropriately selected depending on the purpose. The average degree of polymerization of the PVA-based resin is, for example, 1,000 to 10,000, preferably 1,200 to 5,000, and more preferably 1,500 to 4,500. The average degree of polymerization is determined in accordance with JIS K 6726-1994.

[0072] Examples of methods for producing the polarizer 121 include a method (I) in which a PVA-based resin film alone is stretched and dyed, and a method (II) in which a laminate (i) having a resin substrate and a polyvinyl alcohol-based resin layer is stretched and dyed, etc. Method (I) is a well-known and commonly used method in the art, and therefore a detailed description thereof will be omitted.

[0073] Method (II) preferably includes a step 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 to produce a polarizer on the resin substrate. Laminate (i) can be formed by applying a coating liquid containing a polyvinyl alcohol-based resin onto a resin substrate and drying the coating liquid. Alternatively, laminate (i) may be formed by transferring a polyvinyl alcohol-based resin layer onto the resin substrate. Details of the above-mentioned manufacturing method (II) are described, for example, in JP 2012-73580 A, which is incorporated herein by reference.

[0074] [First and second protective films] 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 for forming the first protective film 122 and the second protective film 123 include polyester resins such as polyethylene terephthalate (PET), cellulose resins such as triacetyl cellulose (TAC), cycloolefin resins such as norbornene resins, olefin resins such as polyethylene and polypropylene, and (meth)acrylic resins. Among these, polyethylene terephthalate (PET) is preferable. Note that "(meth)acrylic resin" refers to an acrylic resin and / or a methacrylic resin.

[0075] As the (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 in, for example, JP 2006-309033 A, JP 2006-317560 A, JP 2006-328329 A, JP 2006-328334 A, JP 2006-337491 A, JP 2006-337492 A, JP 2006-337493 A, JP 2006-337569 A, JP 2007-009182 A, JP 2009-161744 A, and JP 2010-284840 A. These descriptions are incorporated herein by reference.

[0076] The first protective film 122 and the second protective film 123 can be laminated to the polarizer 121 via any appropriate adhesive layer. The resin substrate used in producing the polarizer 121 is peeled off before or after laminating the first protective film 122 and the second protective film 123 to the polarizer 121.

[0077] The thickness of first protective film 122 and 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.

[0078] The modulus of elasticity of first protective film 122 and 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 such a range, a multilayer structure 1B having excellent puncture resistance can be obtained.

[0079] [Adhesive layer] The adhesive layer 18 can be formed from any appropriate adhesive. Examples of adhesives that can be used include adhesives whose base polymer is an acrylic polymer, a silicone polymer, polyester, polyurethane, polyamide, polyether, a fluorine-based polymer, or a rubber-based polymer. Preferably, an acrylic adhesive is used. This is because acrylic adhesives have excellent optical transparency and exhibit adhesive properties such as appropriate wettability, cohesion, and adhesion, and can be excellent in weather resistance, heat resistance, and the like. In particular, acrylic adhesives made of an acrylic polymer having 4 to 12 carbon atoms are preferred.

[0080] The thickness of the pressure-sensitive 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, when the multilayer structure 1B is attached to an optical element such as a liquid crystal cell to produce an optical laminate, the obtained optical laminate has excellent flexibility and excellent puncture resistance.

[0081] [Release film] Release film 19 can be formed from a resin such as polyethylene terephthalate (PET), polyethylene (PE), or polypropylene (PP). The thickness of 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. Release film 19 is peeled off at the interface with pressure-sensitive adhesive layer 18 before multilayer structure 1B is attached to an optical element such as a liquid crystal cell.

[0082] Thus, in the multilayer structure, the resin layer 10 may be composed of one layer or multiple layers. In either case, by cutting the glass layer 30 so that the thickness of the molten layer 35 remaining in the glass layer 30 is less than 3 μm, it is possible to prevent cracks from occurring in the glass layer 30. Even when the resin layer 10 is composed of multiple layers, the laser cutting method is the same as in the first embodiment, etc.

[0083] In addition, the multilayer structure 1A according to the first modification of the first embodiment may employ a laminated structure similar to the resin layer of the multilayer structure 1B.

[0084] [Example 1] In Example 1, a multilayer structure having the structure shown in Fig. 15 was produced using the manufacturing process shown in Figs. 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. 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 then investigated. Thirty samples were produced, and measurements were taken for all of the samples.

[0085] In the multilayer structure produced in Example 1, alkali-free glass was used as the material for the glass layer and had a thickness of approximately 100 μm. An ultraviolet-curable epoxy adhesive was used as the material for the adhesive layer and had a thickness of approximately 1.5 μm. An acrylic resin was used as the material for the first protective film and had a thickness of approximately 40 μm. An iodine-containing polyvinyl alcohol resin was used as the material for the polarizer and had a thickness of approximately 5 μm. An acrylic resin was used as the material for the second protective film and had a thickness of approximately 40 μm. An acrylic polymer was used as the material for the adhesive layer and had a thickness of approximately 30 μm. A polyethylene terephthalate (PET) was used as the material for the release film and had a thickness of approximately 38 μm.

[0086] [Comparative Example 1] In Comparative Example 1, a multilayer structure having the same layer structure as in Example 1 was produced using 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 were the same as in Example 1.

[0087] Comparative Example 2 In Comparative Example 2, a multilayer structure having the same layer structure as in Example 1 was produced using 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 were the same as in Example 1.

[0088] [Example 2] In Example 2, a multilayer structure having the structure shown in Figure 1 was produced using the same manufacturing process as in Example 1. 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. The number of samples and measurement items were the same as in Example 1.

[0089] In the multilayer structure produced in Example 2, the glass layer was made of alkali-free glass and had a thickness of approximately 100 μm. The adhesive layer was made of a UV-curable epoxy adhesive and had a thickness of approximately 1.5 μm. The resin layer was made of a polyethylene terephthalate resin and had a thickness of approximately 150 μm.

[0090] Comparative Example 3 In Comparative Example 3, a multilayer structure having the same layer structure as in Example 2 was produced using 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 were the same as in Example 1.

[0091] Table 1 summarizes the results of Example 1, Example 2, and Comparative Examples 1 to 3. [Table 1] As shown in 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 protrusion of the glass layer from the side of the resin layer was less than 15 μm, and the probability of cracks occurring in the glass layer was 0%.

[0092] In contrast, it was found that the greater the thickness of the molten layer beyond 3 μm, the greater the amount of protrusion of the glass layer from the side surface of the resin layer, and the greater the probability of cracks occurring in the glass layer, as in Comparative Examples 1 to 3. In particular, it was found that cracks always occur in the glass layer when the thickness of the molten layer is 10 μm or more.

[0093] In this way, by cutting the glass layer so that the thickness of the molten layer remaining on the glass layer is less than 3 μm, it is possible to prevent cracks from occurring in the glass layer. In addition, it is preferable that the amount of protrusion of the glass layer from the side surface of the resin layer is less than 15 μm.

[0094] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0095] 1, 1A, 1B, 1S Multi-layer structure 10 Resin layer 10a, 30a top surface 10b, 30b bottom side 10c, 30c side 10x through holes 12 Polarizing plate 18 Adhesive layer 19 Release film 20 Adhesive layer 30 glass layers 35 Melting layer 121 Polarizer 122 First protective film 123 Second protective film

Claims

1. A resin layer; a glass layer laminated on the resin layer via an adhesive layer; a melt layer having residual stress formed on the adhesive layer side of the outer periphery of the glass layer, The thickness of the glass layer is 10 μm or more and 300 μm or less, A multi-layer structure, wherein the thickness of the fused layer is less than 3 μm.

2. an outer periphery of the glass layer protrudes from a side surface of the resin layer; The multilayer structure according to claim 1 , wherein the outer periphery of the glass layer protrudes from the side surface of the resin layer by less than 15 μm.

3. an outer periphery of the resin layer protrudes from a side surface of the glass layer; The multilayer structure according to claim 1 , wherein the outer periphery of the resin layer protrudes from the side surface of the glass layer by less than 10 μm.

4. The multilayer structure according to claim 2 , wherein the melting layer is exposed on a surface of the glass layer facing the adhesive layer and on a side surface of the glass layer.

5. The multilayer structure according to claim 1 , wherein the side surface of the resin layer is an inclined surface that forms an angle of less than 90 degrees with the surface of the resin layer facing the adhesive layer.

6. The multilayer structure according to claim 1 , wherein the resin layer is composed of a plurality of layers.

7. The multi-layer structure according to claim 6 , wherein the plurality of layers includes a polarizing plate having a polarizer.

8. preparing a first multi-layer structure having a resin layer and a glass layer laminated on the resin layer via an adhesive layer, the first multi-layer structure defining a plurality of product regions; a step of irradiating a laser beam from the resin layer side onto an outer periphery of the product region of each of the first multilayer structures to form a through hole in the resin layer; and a step of irradiating a laser beam from the glass layer side onto an outer periphery of each of the product regions of the first multilayer structure to cut the glass layer, thereby dividing each of the product regions into individual pieces to produce a plurality of multilayer structures, The thickness of the glass layer is 10 μm or more and 300 μm or less, In the step of forming the through hole in the resin layer, a molten layer having a predetermined thickness is formed in a thickness direction of the glass layer from a surface of the glass layer exposed in the through hole, In the step of producing the plurality of multi-layer structures, the glass layer is cut at a position where the thickness of the molten layer becomes less than 3 μm.

9. The method for manufacturing a multilayer structure according to claim 8 , wherein the melt layer has a thickness of less than 3 μm in the step of forming through holes in the resin layer.

10. The method for manufacturing a multi-layer structure according to claim 8 or 9, wherein a femtosecond laser is used in the step of manufacturing the plurality of multi-layer structures.

11. 11. The method for manufacturing a multi-layer structure according to claim 8, wherein a carbon dioxide gas laser is used in the step of forming the through holes in the resin layer.

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