TW202019697A - Thin glass laminate comprising a resin film and a piece of thin glass disposed on an upper side of the resin film and having an end face that has an inclined surface or a curved surface - Google Patents

Abstract

The present invention provides a thin glass laminate that has excellent property of bending durability as being capable of preventing cracking caused by bending of thin glass. The thin glass laminate of the present invention includes a resin film and a piece of thin glass disposed on at least an upper side of the resin film. The thin glass has a thickness of 30[mu]m-150[mu]m. Further, at least a portion of an end face of the thin glass is formed of an inclined surface and/or a curved surface extending to a lower outside. In one embodiment, the upper end of the thin glass, at least a portion of the end face, is formed of an inclined surface or a curved surface extending to the lower outside.

Description

Thin glass laminate

The invention relates to a thin glass laminate.

Background of the invention Conventionally, glass laminates composed of glass materials and resin films such as optical films are often used for components constituting image display devices, such as substrates for display elements, sealing materials for organic EL elements, and front protection plates. In recent years, image display devices have become lighter and thinner, and there is a tendency to require flexibility. Therefore, it is required to use a glass laminate made of a thin glass material. Originally, the glass material was not easy to handle due to its fragility, and with the thinning, the problem was more significant. In particular, in a glass laminate formed by arranging a glass material on the outermost layer, there is a problem that cracks are likely to occur when the glass laminate is bent (especially when the glass material side is bent into a convex shape). It is generally known that this is because when the glass is bent, once a wedge-shaped depression occurs, the stress will be concentrated there. However, even if the wedge-shaped depression can be reduced, a complete smooth surface cannot be obtained in principle.

Prior technical literature Patent Literature Patent Literature 1: Japanese Patent No. 4122139

Summary of the invention Problems to be solved by invention The present invention was made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a thin glass laminate that can prevent breakage due to bending of thin glass due to the smoothness and shape of the end surface of the thin glass and has excellent bending durability .

Means for Solving the Problem The thin glass laminate of the present invention includes a resin film and a thin glass disposed at least above the resin film; the thickness of the thin glass is 30 μm to 150 μm, and at least a part of the end surface of the thin glass is It consists of a slope and/or a curved surface extending downward and outward. In one embodiment, at the upper end of the thin glass, at least a part of the end surface is formed by the inclined surface or curved surface extending downward and outward. In one embodiment, at least a part of the end surface of the thin glass is formed by the inclined surface extending downward and outward, and the angle θ ₁ formed by the upper surface of the thin glass and the inclined surface extending downward and outward is greater than 90° and Below 140°. In one embodiment, at least a part of the end surface of the thin glass has an upward curved surface protruding outward as the curved surface, and the upward curved surface is a junction A at (curved surface height h1)×3/4 of the curved surface Curved surface with an angle θ ₂ greater than 90° from the top of thin glass. In one embodiment, the angle θ _{2 is} greater than 90° and less than 140°. In one embodiment, at least a part of the end surface of the thin glass further has a downward curved surface protruding outward as the curved surface. In one embodiment, at least a part of the end surface of the thin glass is composed of the inclined surface and/or the curved surface and a vertical surface. In one embodiment, in the thin glass, the height H1 of the portion of the end surface formed by the inclined surface extending downward and the curved surface or the curved surface is 0.1% or more with respect to the thickness of the thin glass. In one embodiment, the ratio (H1:H2) of the height H1 of the portion of the end surface formed by the inclined surface or the curved surface extending downward to the outside and the height of the portion formed by the vertical surface of the end surface is 1:9 ~9.99: 0.01. In one embodiment, the arithmetic average surface roughness Ra of the end surface of the thin glass is 150 nm or less. In one embodiment, the 10-point average roughness Rz of the end surface of the thin glass is 500 nm or less. In one embodiment, the resin film is arranged to protrude from thin glass. In one embodiment, in cross-section, the height difference between the resin film and the thin glass is 200 μm or less. In one embodiment, the resin film is an optical film. In one embodiment, the optical film is a polarizing plate. In one embodiment, the resin film has a transparent conductive layer. In one embodiment, the thin glass and the resin film are laminated through an adhesive. According to another aspect of the present invention, a method for manufacturing the above thin glass laminate can be provided. This manufacturing method includes laminating thin glass and a resin film to form a laminate A, cutting the laminate A to a predetermined size, and polishing the end surface of the cut laminate B by polishing.

Effect of invention According to the present invention, by forming at least a part of the end surface of the thin glass from a slope or a curved surface, it is possible to provide a thin glass laminate in which the thin glass is not easily broken and has excellent bending durability.

Forms for carrying out the invention A. Overall composition of thin glass laminate The thin glass laminate of the present invention includes a resin film and a thin glass disposed at least above the resin film; in the thin glass, at least a part of the end surface of the thin glass is composed of a slope and/or a curved surface extending downward and outward. The thin glass laminate of the present invention has an inclined surface or a curved surface extending downward and outward on at least a part of the end surface of the thin glass, so that the thin glass is not easily broken and has excellent bending durability. I think this is because when the thin glass laminate is bent, the local load can be reduced by dispersing the external force applied to the thin glass laminate by the inclined surface or curved surface extending downward and outward. And this effect is more pronounced when the end faces contain curved surfaces. Hereinafter, the representative structure of the thin glass laminate of the present invention will be specifically described with reference to FIGS. 1 to 6.

FIG. 1 is a schematic cross-sectional perspective view of a thin glass laminate according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of an end portion of the thin glass laminate shown in FIG. 1. The thin glass laminate 100 of this embodiment includes a resin film 10 and a thin glass 20 disposed on at least one surface (upper side) of the resin film 10. At least a part of the end surface of the thin glass 20 includes a slope 21 that extends downward and outward. In one embodiment, the thin glass 20 and the resin film 10 can be laminated through any suitable adhesive or adhesive (not shown). In addition, on the surface of the resin film 10 where the thin glass 20 is disposed, the entire surface thereof is preferably covered with the thin glass 20 (that is, the end of the resin film 10 and the end of the thin glass 20 should be the same). In addition, in this specification, for convenience, the thin glass laminate 100 has the thin glass 20 side (upper side of the paper surface) as the upper side, and the resin film 10 side (lower side of the paper surface) as the lower side, but how to use the thin glass laminate body Not limited to this.

The angle θ ₁ formed by the upper surface 23 of the thin glass 20 and the inclined surface 21 extending downward and outward is preferably greater than 90°, more preferably greater than 90° and less than 150°, more preferably greater than 90° and less than 140°, and more preferably It is 92°~140°. If it is within the above range, the effect of the present invention described above is more remarkable. The thin glass may have a plurality of slopes extending downward and outward with different slopes. In one embodiment, the thin glass may further have a slope (not shown) that extends downward and inward. For example, at the lower end of the thin glass 20, a slope extending downward and inward may be formed on at least a part of the end surface. The angle θ ₁ ′ formed by the lower surface of the thin glass and the inclined surface extending downward inward is preferably greater than 90°, more preferably greater than 90° and less than 150°, and more preferably 92° to 140°.

3 is a schematic cross-sectional perspective view of a thin glass laminate according to an embodiment of the present invention. 4 is an enlarged cross-sectional view of an end portion of the thin glass laminate shown in FIG. 3. In the thin glass laminate 100 ′ of this embodiment, the thin glass 20 includes the curved surface 22 on at least a part of the end surface of the thin glass 20. As shown in the example, the curved surface 22 is preferably convex outward. In addition, the curved surface constituting the end surface of the thin glass 20 may be a curved surface with a fixed curvature, or may be a collection of curved surfaces defined by an arbitrary curvature (ie, may have a plurality of curved surfaces with different curvatures). Hereinafter, in this specification, a curved surface formed by a continuous one curve with a fixed curvature is referred to as a "1 curved surface". Therefore, "a collection of curved surfaces defined with arbitrary curvature" can also be renamed "a collection of 1 curved surface".

In one embodiment, the thin glass 20 has a curved surface 22 at least part of its end surface at (height h1 of the curved surface 22) × 3/4 (based on the end 22b below the curved surface 22, the height is h1 × 3/ (4 points) a curved surface formed by the junction surface A and the upper surface 23 of the thin glass at an angle θ ₂ greater than 90° (hereinafter, the curved surface is referred to as an “upward curved surface”). The angle θ _{2 is} preferably greater than 90° and below 150°, more preferably greater than 90° and below 140°, and more preferably 92° to 140°. If it is within the range, the effect of the present invention is remarkable.

5 is a schematic cross-sectional view of a thin glass laminate according to an embodiment of the present invention. 6 is an enlarged cross-sectional view of an end portion of the thin glass laminate shown in FIG. 5. In the thin glass laminate 100" of this embodiment, the thin glass 20 includes an upward curved surface 22 and a downward curved surface 24 on at least a part of the end surface of the thin glass 20. The downward curved surface 24 means that the curved surface 24 is located at the height of the curved surface 24 h1') × 1/4 (based on the lower edge 24b of the curved surface 24 as the reference and the height h1' × 1/4) the curved surface formed by the junction B and the lower surface 25 of the thin glass θ ₃ greater than 90 The angle θ _{3 is} preferably greater than 90° and below 150°, and more preferably 92° to 140°. As long as it is within the range, bending resistance can be maintained. The downward curved surface should be convex outward.

In one embodiment, as shown in FIGS. 1 to 6, at the upper end of the thin glass 20, at least a part of the end surface is composed of a slope 21 or a curved surface 22 (preferably an upward curved surface) extending downward and outward. In the above embodiment, the upper end edges 21a, 22a of the inclined surface 21 or the curved surface 22 extending downward and outward are in contact with the upper surface 23 of the thin glass. According to the above configuration, a thin glass laminate can be made which is weak at the upper end of the thin glass and receives a larger external force when bending, and the local load is reduced and it is more difficult to break.

In one embodiment, as shown in FIGS. 1 to 6, at least a part of the end surface of the thin glass 20 is composed of a slope and/or a curved surface extending downward and outside, and a vertical surface 25. In addition, the vertical plane 25 means a plane that is slightly vertical with respect to the upper surface 23 of the resin film 10, and the angle formed by the vertical surface 25 and the upper surface 23 is preferably 85° to 95°, and more preferably 85° to 90°. This is the allowable range due to the thin glass thickness. In one embodiment, as shown in FIGS. 1 and 3, above the thin glass 20, the end surface is composed of a slope 21 or an upward curved surface 22 extending downward and outward; below, the end surface is composed of a vertical surface 25. In another embodiment, as shown in FIG. 5, the thin glass 20 has an upward curved surface 22, a vertical surface 25 and a downward curved surface 24 in order from the top. As long as the end surface of the thin glass includes a slope or curved surface that extends downward and outward, and a vertical surface, it is not necessary to reduce the amount of glass material to exert the effect of forming a slope or curved surface that extends downward and outward. Thin glass laminate with better bending durability. In addition, the resin film may also be configured to protrude or be recessed from the thin glass. At this time, a height difference will appear between the resin film and the thin glass in cross-section, and the height difference should be small. The height difference between the resin film and the thin glass is preferably 200 μm or less, and more preferably 100 μm or less.

The shape of the thin glass (and the thin glass laminate) in plan view may be any appropriate shape. The angle formed by two adjacent sides of the thin glass in a plan view may be a right angle or a non-right angle. Moreover, two adjacent sides can also be connected by curves. In addition, the top-view shape of the thin glass can be defined by a straight line, it can also have any arbitrary and appropriate curvature, or it can be defined by a straight line and a curve. Thin glass can also be round. This is because as long as the end face of the present invention is suitable, the bending resistance of the glass is not restricted by the shape of the face.

In the present invention, for the entire circumference of the thin glass, as described above, the end surface thereof may have a slope or curved surface (preferably an upward curved surface) extending downward, and a part of the periphery of the thin glass as described above may have a slope surface which extends downward and outward. Or curved surface (preferably upward curved surface). In addition, when the thin glass laminate is rectangular, its four sides may have inclined surfaces or curved surfaces (preferably upward curved surfaces) extending outward and downward on the four sides as described above, and may have downward outward expansion as described above on the opposite side The inclined surface or curved surface (preferably upward curved surface). When the end face of the opposite set of edges has an inclined surface or a curved surface (preferably an upward curved surface) extending downward and outward, the side is preferably a curved side. In addition, the thin glass 20 may have both an inclined surface and a curved surface extending downward and outward at one end surface.

In thin glass, the height H1 of the portion formed by the inclined surface or curved surface extending downward and outside should be 0.1% or more, preferably 10% or more, more preferably 20% or more, and 40 more than the thickness of the thin glass. %the above. In one embodiment, the upper limit of H1 is 100%. In another embodiment, H1 is preferably less than 100%, more preferably 99.9% or less, more preferably 90% or less, and still more preferably 80% or less. If it is within the above range, a thin glass laminate that is not easily damaged can be produced. "Height H1 of the portion of the end surface formed by the inclined surface or curved surface extending downward and outward" means the total height of the inclined surface and curved surface extending downward and outward. In addition, the portion other than the portion where the end surface is composed of a slope or a curved surface extending downward and outward may be a portion where the end surface is composed of a vertical surface.

The ratio (H1: H2) of the ratio of the height H1 of the portion of the end surface composed of the inclined surface or curved surface extending downward to the height of the portion of the end surface composed of the vertical surface (that is, the height of H1 minus the thickness of the thin glass) should be 1 : 9~10:0, preferably 1:9~9.99:0.01, preferably 2:8~9:1, more preferably 4:6~6:4. If it is within the above range, a thin glass laminate that is not easily damaged can be produced.

The curvature radius of the above curved surface is preferably 50 μm to 1500 μm, and more preferably 50 μm to 1000 μm. If it is within the above range, a thin glass laminate that is not easily damaged can be produced. The above-mentioned curved surface can be defined as a single, or can be composed of any set of curvatures.

The fan-shaped central angle α including the curves constituting the above-mentioned curved surface (1 curved surface) is preferably 5° to 95°, more preferably 10° to 90°, and even more preferably 30° to 90°. If it is within the above range, a thin glass laminate that is not easily damaged can be produced.

The thickness of the thin glass is preferably 30 μm to 150 μm, and most preferably 50 μm to 100 μm. If it is within the above range, a thin glass laminate having excellent flexibility can be obtained without compromising the physical properties (hardness, CTE, barrier properties, etc.) of the thin glass.

The thickness of the resin film can be set to an arbitrary and appropriate thickness depending on the application. The thickness of the resin film is, for example, 10 μm to 500 μm, preferably 30 μm to 200 μm.

The lower limit of the ratio of the thickness of the resin film to the thickness of the thin glass (resin film thickness/thin glass thickness) is preferably 0.2 or more. If it is within the above range, the thin glass can be prevented from scattering. The upper limit of the ratio of the thickness of the resin film to the thickness of the thin glass (resin film thickness/thin glass thickness) is preferably 5 or less. If it is within the range, even if the thin glass is bent into a protrusion, it can still withstand the stress applied to the glass surface. The ratio of resin film thickness to thin glass thickness (resin film thickness/thin glass thickness) is preferably 0.3 to 3. If the thin glass laminate is processed within the above range, even if the thin glass is broken, the thin glass can be prevented from being damaged.

The thin glass laminate may include any other layers as appropriate. For example, arbitrary and appropriate other layers may be arranged on the surface of the thin glass opposite to the resin film. The layer may be a layer having a thickness of 100 μm or less, and as a specific example, a protective film temporarily arranged to prevent adhesion or contamination of foreign substances on the surface of the thin glass. In addition, the glass surface may also contain functional layers such as transparent electrodes, anti-reflection layers, and anti-fouling layers. The thickness of the functional layer is preferably 1 μm or less.

In one embodiment, the surface of the thin glass laminate on the opposite side of the thin glass from the resin film is configured so that no other layers are arranged (that is, the thin glass is formed as the outermost layer). The thin glass laminate composed of thin glass on the outermost layer has a tendency to break easily, especially when the thin glass side is bent into a protrusion, but the thin glass laminate according to the present invention is even located on thin glass. It is composed of the outermost layer, and the bending durability is still good.

B. Thin glass The shape of the above thin glass is plate-shaped. When the thin glass is classified according to the composition, for example, soda lime glass, boric acid glass, aluminosilicate glass, quartz glass, etc. may be mentioned. In addition, according to the classification of the alkaline component, non-alkali glass and low-alkali glass can be cited. The content of the alkali metal components (such as Na ₂ O, K ₂ O, and Li ₂ O) of the thin glass is preferably 15% by weight or less, and more preferably 10% by weight or less.

The light transmittance of the above-mentioned thin glass at a wavelength of 550 nm is preferably 90% or more. The refractive index n _{g of the} above thin glass at a wavelength of 550 nm is preferably 1.4 to 1.6.

The average thermal expansion coefficient of the above thin glass is preferably 10 ppm °C ^-1 ~ 0.5 ppm °C ^-1 , more preferably 7 ppm °C ^-1 ~ 0.5 ppm °C ^-1 .

The density of the thin glass is preferably 2.3g/cm ³ ~3.0g/cm ³ , more preferably 2.3g/cm ³ ~2.7g/cm ³ .

The arithmetic average surface roughness Ra of the end surface of the thin glass is preferably 150 nm or less, more preferably 130 nm, and even more preferably 110 nm or less. The lower limit of the arithmetic average surface roughness Ra of the end surface of the thin glass is, for example, 10 nm or more.

The 10-point average roughness Rz of the end surface of the thin glass is preferably 500 nm or less, more preferably 450 nm or less, and even more preferably 400 nm or less. The lower limit of the 10-point average roughness Rz of the end surface of the thin glass is, for example, 200 nm or more.

The above-mentioned thin glass forming method may adopt any appropriate method. Representatively speaking, the above thin glass can be formed into a thin plate by melting a mixture containing main raw materials such as silica or alumina, antifoaming agents such as thenardite or antimony oxide, and reducing agents such as carbon at a temperature of 1400°C to 1600°C. After cooling to prepare. Examples of the method of forming the thin plate of the above-mentioned thin glass include an orifice drawing method, an overflow melting method, and a floating method. The thin glass formed into a plate shape by these methods can be thinned or improved in smoothness, so it can be chemically polished with a solvent such as hydrofluoric acid according to demand.

The aforementioned thin glass can be used as it is, or it can be used after grinding the commercially available thin glass to a desired thickness. Examples of commercially available thin glass include "7059", "1737" or "EAGLE2000" manufactured by Corning, "AN100" manufactured by AGC, "NA-35" manufactured by NH Techno Glass, and "OA-10" manufactured by Nippon Electric Glass. ", "D263" or "AF45" manufactured by SCHOTT.

C. Resin film In one embodiment, an optical film is used as the resin film. Examples of the optical film include a polarizing plate (an optical film having a polarizing function), a retardation plate, and an isotropic film. The resin film may have a single-layer structure or a multi-layer structure.

Any and appropriate materials can be used as the material constituting the above-mentioned resin film. Examples of the material constituting the resin film include polyvinyl alcohol (PVA) resins, polyolefin resins, cyclic olefin resins, polycarbonate resins, cellulose resins, polyester resins, and polyamide resins. , Polyimide resin, polyether resin, polystyrene resin, (meth)acrylic resin, (meth)acrylic acid urethane resin, polyphenol resin, acetate resin, Epoxy resins, polysiloxane resins, polyarylate resins, polyphenol resins, polyetherimide resins, epoxy resins, urethane resins, polysiloxane resins, etc.

The elastic modulus of the above resin film at 23°C is preferably 1.5GPa~10GPa, more preferably 1.8GPa~9GPa, more preferably 1.8GPa~8GPa. If it is within the above range, a thin glass laminate having a high effect of protecting thin glass and not easily broken can be produced. In addition, the elastic modulus of the present invention can be measured by a tensile test.

In one embodiment, the resin film has a transparent conductive layer. The resin film with a transparent conductive layer is formed by disposing a transparent conductive layer on the resin film. Examples of the transparent conductive layer include a metal oxide layer, a metal layer, a conductive polymer-containing layer, a metal nanowire-containing layer, and a metal mesh layer.

D. Protective film In one embodiment, a protective film may be arranged on the outer surface of the thin glass. The protective film temporarily protects the thin glass from foreign materials and the like. Materials constituting the protective film include polyethylene, polyvinyl chloride, polyethylene terephthalate, polyvinylidene chloride, polypropylene, polyvinyl alcohol, polyester, polycarbonate, polystyrene, polypropylene Nitrile, ethylene vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-methacrylic acid copolymer, nylon, cellophane, polysiloxane resin, etc.

E. Manufacturing method of thin glass laminate In one embodiment, the thin glass laminate may be formed by laminating thin glass and a resin film to form a laminate A, and cutting the laminate A to a predetermined size, then cutting the end (end face) of the resulting laminate B ) Is obtained by grinding.

In one embodiment, the laminate A is formed by laminating the resin film and the thin glass through an adhesive. Any appropriate adhesive can be used as the above-mentioned adhesive. Examples of the above-mentioned adhesive include adhesives containing the following resins: resins having cyclic ether groups such as epoxy groups, epoxypropyl groups, and oxetane groups, acrylic resins, and polysiloxane resins. UV-curable adhesives should be used.

In another embodiment, the laminate A may be formed by applying a resin solution to thin glass.

The cutting method of the above-mentioned laminated body A can adopt any appropriate method. The cutting method may be, for example, a method of cutting using fullback, UV laser, waterjet, end mill, etc.

The crack length of the end surface of the laminate B is preferably 10 μm to 300 μm, and more preferably 10 μm to 200 μm. The crack length refers to the maximum value of the length component perpendicular to the crack end surface when the laminate B is viewed from above.

The method of polishing the end surface of the laminate B is preferably polished. Polishing is a method in which a polishing cloth abuts against the end surface of the laminate B to perform a relative movement. When the polishing cloth performs a relative motion, a slurry containing free abrasive particles is supplied to the surface to be processed and the end surface is polished. In the present invention, an end surface having a slope and/or a curved surface extending downward and outward as described above can be formed by polishing.

It is preferable to polish the end surface of the laminated body B with another sheet glass or resin plate sandwiching the laminated body B. In this way, on the thin glass surface, the slurry enters the upper part of the thin glass by the glass surface abutting the polishing cloth, then the contact effect caused by the polishing cloth can be reduced on the thin glass resin film side, so it can be formed well. As described above, the end surface of the inclined surface and/or curved surface extending downward and outward.

Nylon brush should be used for polishing cloth used for polishing. The diameter of the brush should be 0.1mm~0.5mm, more preferably 0.1mm~0.3mm.

For the free abrasive particles, for example, cerium oxide, silicon oxide, indium oxide, etc. can be used. In particular, the use of cerium oxide will cause the substitution reaction between the silicon component of the glass and the cerium, so it can be cut while dissolving the glass, which is quite suitable. The particle size of the free abrasive particles is preferably about 1 μm to 5 μm.

The polishing amount during polishing is preferably 300 μm or less, and preferably 200 μm or less, and more preferably 100 μm or less. If the target amount of polishing is too much, the thin glass laminate of the desired shape may not be obtained; for example, there may be defects such as peeling of the interface between the resin layer and the glass due to the nylon brush.

In the thin glass laminate obtained by polishing the laminate B, the arithmetic average roughness Ra of the glass portion is preferably 150 nm or less, more preferably 130 nm, and even more preferably 110 nm or less. The lower limit of the arithmetic average roughness Ra of the glass portion is, for example, 10 nm or more. In addition, the 10-point average roughness Rz of the glass portion is preferably 500 nm or less, more preferably 450 nm or less, and even more preferably 400 nm or less. The lower limit of the 10-point average roughness Rz of the glass portion is, for example, 200 nm or more. Examples

The present invention is specifically described below with examples, but the present invention is not limited to these examples. The evaluation methods in Examples and Comparative Examples are as follows.

[Production Example 1] Production of a thin glass/resin film laminate (laminate A) A thin glass/resin film is laminated on a thin glass with a thickness of 100 μm (manufactured by Nippon Electric Glass Co., Ltd., trade name “OA-10”) through an adhesive (epoxy-based UV-curable adhesive, thickness: 10 μm) Laminated body (Laminated body A). For the resin film, a polarizer having a thickness of 5 μm and an acrylic film having a thickness of 40 μm are laminated. In addition, in this resin film system, an acrylic film is laminated so as to face the thin glass.

[Example 1] The above-mentioned laminated body A was cut with a cutting device (manufactured by SHODA TECHTRON CO., trade name "CCM-550A type") to obtain a laminated body B. The cutting condition is that under the condition that both ends of the sample are fixed, a knife with a diamond blade number #325 with a diameter of 200 mm is used to cut at a speed of 3000 rpm and a speed of 40 mm/min (size: 60 mm×120 mm). Then, after laminating 15 pieces of laminate B, sandwich the plate glass (60 mm × 120 mm) with a thickness of 500 μm between the upper and lower sides, and use a polishing device (manufactured by SHODA TECHTRON CO., trade name “BPM-380C”) to surround the four sides The end surface treatment is performed to obtain a thin glass laminate. In this end surface treatment, a 6-inch-diameter roller made of a nylon brush with a diameter of 0.2 mm was rotated (rotation speed 900 rpm, brush contact amount: 5 mm) and the nylon brush was used to apply the end surface while providing the polishing liquid. Grind. The polishing liquid is a polishing liquid containing cerium oxide particles (particle size: 2 μm to 3 μm) in water. The final polishing amount was set to 100 μm.

[Example 2] After the surface protective film (manufactured by Nitto Denko Corporation, RP207) was attached to the thin glass surface of the laminate A, it was cut in the same manner as in Example 1 and polished to obtain a thin glass laminate.

[Comparative Example 1] The laminate A was cut with a UV laser (wavelength 355 nm, pulse width 15 ps, speed 1000 mm/s, 100 scans) to obtain a thin glass laminate.

[Comparative Example 2] After the laminated body A is roughly cut with a cutting machine, 15 pieces are laminated, and then a rotary cutter (manufactured by MISUMI, XAL series super hard end mill (square end mill), 2 blades/blade length 3D type) The end surface treatment is performed to obtain a thin glass laminate. The cutting conditions are such that the cutting amount is 0.5 mm, the rotation speed is 25000 rpm, and the speed is 1500 mm/s.

[Comparative Example 3] The laminate A was cut with a cutting device (manufactured by SHODA TECHTRON CO., model CCM-550A) to obtain a thin glass laminate. The cutting conditions are under the condition that both ends of the sample are fixed, and the cutting is carried out with a knife with a diamond blade number #325 with a diameter of 200 mm and a rotation speed of 3000 rpm and a speed of 40 mm/min.

(Evaluation) The thin glass laminate obtained in Examples and Comparative Examples (Example 2 was a thin glass laminate after the protective film was peeled off) was used for the following evaluation. The results are shown in Table 1. (1) Shape evaluation Observe the cross-section of the thin glass laminate with SEM to determine the shape of the end face (whether or not a curved surface is formed above the thin glass; the curvature of the curved surface; the junction A at (surface height h1)×3/4 of the curved surface) The angle θ ₂ formed with the top of the thin glass) In addition, the thin glass laminates of Comparative Examples 1 to 3 did not form a curved surface on the thin glass end surface, and the angle formed by the upper surface and the vertical surface was 90°. In addition, the arithmetic average surface roughness Ra and the arithmetic average surface roughness Ra (field of view: 50 μm□) of the thin glass end surface were measured by AFM. (2) Bending strength For a thin glass laminate (dimensions: 60 mm × 110 mm), the long side was bent to perform a two-point bending test and the distance between two points at the time of fracture was measured. The distance between two points means the distance between one end and the other end in the longitudinal direction, that is, the distance that is shortened as the thin glass laminate is bent when the thin glass laminate is bent starting from the center in the longitudinal direction. Also, the narrower the distance between the two points, the higher the bending strength.

[Table 1]

As is clear from Table 1, by forming a predetermined curved surface on the end surface of the thin glass, a thin glass laminate having excellent bending durability can be produced.

100, 100', 100": thin glass laminate 10: thin glass 20: resin film 21: slope 21a, 22a: upper edge 22: (upward) curved surface 22b, 24b: lower edge 23: thin glass top 24: downward Curved surface 25: vertical surface, under thin glass (figure 6) A, B: junction h1: height of curved surface 22 h1': height of curved surface 24 H1: height of part of the end surface consisting of a slope or curved surface extending downward and outward : The height of the portion of the end face composed of the vertical plane θ ₁ ～θ ₃ : Angle α: Sector central angle

FIG. 1 is a schematic cross-sectional perspective view of a thin glass laminate according to an embodiment of the present invention. 2 is an enlarged cross-sectional view of an end portion of a thin glass laminate according to an embodiment of the present invention. 3 is a schematic cross-sectional perspective view of a thin glass laminate according to an embodiment of the present invention. 4 is an enlarged cross-sectional view of an end portion of a thin glass laminate according to an embodiment of the present invention. 5 is a schematic cross-sectional perspective view of a thin glass laminate according to an embodiment of the present invention. 6 is an enlarged cross-sectional view of an end portion of a thin glass laminate according to an embodiment of the present invention.

100': thin glass laminate

10: resin film

20: Thin glass

22: (upward) surface

Claims (18)

A thin glass laminate comprising a resin film and thin glass arranged at least above the resin film; The thickness of the thin glass is 30μm~150μm, Furthermore, at least a part of the end surface of the thin glass is composed of a slope and/or a curved surface extending downward and outward. The thin glass laminate according to claim 1, wherein at least a part of the end surface at the upper end of the thin glass is composed of the inclined surface and/or curved surface extending downward and outward. The thin glass laminate as claimed in claim 1 or 2, wherein at least a part of the end surface of the thin glass is composed of the inclined surface extending downward and outward, and the angle formed by the upper surface of the thin glass and the inclined surface extending downward and outward θ _{1 is} greater than 90° and below 140°. The thin glass laminate as claimed in claim 1, wherein at least a part of the end surface of the thin glass has an upward curved surface protruding outward as the curved surface, and the upward curved surface is located in (curved surface height h1)×3/4 The angle θ ₂ formed by the junction A and the upper surface of the thin glass is greater than 90°. The thin glass laminate as claimed in claim 4, wherein the aforementioned angle θ _{2 is} greater than 90° and less than 140°. The thin glass laminate according to claim 4 or 5, wherein at least a part of the end surface of the thin glass further has a downward curved surface protruding outward as the aforementioned curved surface. The thin glass laminate according to any one of claims 1 to 6, wherein at least a part of the end surface of the thin glass is composed of the inclined surface extending downward and/or the curved surface and the vertical surface. The thin glass laminate according to any one of claims 1 to 7, wherein in the thin glass, the height H1 of the portion of the end surface formed by the inclined surface or the curved surface extending downward and outward relative to the thickness of the thin glass is 0.1% or more. The thin glass laminate as claimed in claim 7 or 8, wherein the ratio of the height H1 of the portion of the end surface formed by the inclined surface or the curved surface extending downward to the outside and the height H2 of the portion of the end surface formed by the vertical surface (H1 : H2): 1:9~9.99:0.01. The thin glass laminate according to any one of claims 1 to 9, wherein the arithmetic average surface roughness Ra of the end surface of the thin glass is 150 nm or less. The thin glass laminate according to any one of claims 1 to 10, wherein the 10-point average roughness Rz of the end surface of the thin glass is 500 nm or less. The thin glass laminate according to any one of claims 1 to 11, wherein the aforementioned resin film is configured to protrude from the thin glass. The thin glass laminate according to any one of claims 1 to 12, which has a height difference between the resin film and the thin glass of 200 μm or less in cross-section. The thin glass laminate according to any one of claims 1 to 13, wherein the aforementioned resin film is an optical film. The thin glass laminate as claimed in claim 14, wherein the aforementioned optical film is a polarizing plate. The thin glass laminate as claimed in claim 14 or 15, wherein the aforementioned resin film has a transparent conductive layer. The thin glass laminate according to any one of claims 1 to 16, wherein the thin glass and the resin film are laminated through an adhesive. A method for manufacturing a thin glass laminate, which is used to manufacture a thin glass laminate according to any one of claims 1 to 17, the foregoing manufacturing method includes: laminating thin glass and a resin film to form a laminate A, and laminating the laminate After the body A is cut to a predetermined size, the end surface of the cut laminated body B is polished by polishing.

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