Glass substrate, glass laminate, display device, electronic device, and method for manufacturing glass laminate

Abstract

To provide glass substrates and glass laminates with good flexibility. [Solution] This disclosure provides a glass substrate having a first surface, a second surface facing the first surface, and a side surface, having a thickness of 15 μm or more and 100 μm or less, and having a maximum height Sz of the side surface of 1.5 μm or less.

Description

[Technical Field]

[0001] This disclosure relates to a glass substrate, a glass laminate using the same, a display device and an electronic device, and a method for manufacturing a glass laminate. [Background technology]

[0002] Traditionally, display devices have been fitted with glass or resin cover components to protect them. These cover components protect the display device from impacts and scratches, and therefore require strength, impact resistance, and scratch resistance. Glass cover components have features such as high surface hardness, scratch resistance, and high transparency, while resin cover components are lightweight and resistant to breakage. Generally, the thicker the cover component, the better the protection against impacts the display device has, and the material and thickness of the cover component are selected appropriately based on factors such as weight, cost, and the size of the display device.

[0003] In recent years, there has been a great deal of activity in the development of flexible displays such as foldable displays, rollable displays, and bendable displays, with particular emphasis on the development of foldable displays, or display devices that can be folded.

[0004] In bendable display devices, the cover member also needs to bend to follow the movement of the display device, and therefore, bendable cover members are used. In the case of resin cover members, colorless and transparent polyimide and polyamide-imide films have been developed by modifying their chemical structure (see, for example, Patent Document 1). In the case of glass cover members, research is underway on cover members that can be bent by making the glass thin, such as ultra-thin glass (UTG) (see, for example, Patent Document 2). Among glass types, chemically strengthened glass has particularly high bending resistance. By imbuing the glass surface with expanding stress, it prevents minute scratches on the glass surface from becoming larger during bending, thus making the glass less prone to breakage. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-137864 [Patent Document 2] Japanese Patent Publication No. 2018-188335 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, because chemically strengthened glass is difficult to cut, when manufacturing cover components using chemically strengthened glass, it is necessary to first cut the glass substrate to the desired size, and then apply the chemical strengthening treatment to the cut glass substrate. This means that the subsequent manufacturing process cannot proceed without cutting the large glass substrate, resulting in low productivity.

[0007] Furthermore, even if chemically strengthened glass can be cut, cutting it results in a decrease in strength at the cut surface of the glass substrate because the compressive stress layer formed on the surface of the chemically strengthened glass is absent. In this case, the bending resistance decreases.

[0008] This disclosure has been made in view of the above circumstances, and its main purpose is to provide glass substrates and glass laminates with good flexibility. [Means for solving the problem]

[0009] One embodiment of the present disclosure provides a glass substrate having a first surface, a second surface facing the first surface, and a side surface, having a thickness of 15 μm or more and 100 μm or less, and having a maximum height Sz of the side surface of 1.5 μm or less.

[0010] In this disclosure, it is preferable that the glass substrate does not crack or break when the glass substrate is repeatedly bent 180° 200,000 times such that the distance between the opposing short sides of the glass substrate is 12 mm.

[0011] The glass substrate in this disclosure is preferably chemically strengthened glass.

[0012] In the glass substrate according to this disclosure, when the potassium concentration distribution in the thickness direction of the side surface is divided into ten equal regions in the thickness direction, and these regions are numbered from the first to the tenth region in order from the first surface to the second surface, it is preferable that the average potassium concentration in the first region is higher than the average potassium concentration in the fifth region. In this case, it is preferable that the ratio of the average potassium concentration in the fifth region to the average potassium concentration in the first region is within the range of 0 to 0.7.

[0013] The glass substrate in this disclosure is preferably used in a flexible display.

[0014] Another embodiment of the present disclosure provides a glass laminate having the glass substrate described above and a resin layer disposed on at least one of the first and second surfaces of the glass substrate.

[0015] In the glass laminate described herein, the thickness of the resin layer is preferably 5 μm or more and 60 μm or less.

[0016] In the glass laminate described herein, it is preferable that the composite elastic modulus of the resin layer is 4.7 GPa or higher.

[0017] In the glass laminates of this disclosure, it is preferable that the resin layer contains at least one selected from the group consisting of polyimide resins, epoxy resins, polyesters, polyurethanes, and acrylic resins.

[0018] The glass laminate in this disclosure may further have a second resin layer that covers the side surface of the glass substrate.

[0019] In the glass laminates of this disclosure, it is preferable that the second resin layer contains at least one selected from the group consisting of polyimide resins, epoxy resins, polyesters, polyurethanes, and acrylic resins, or contains a cured product of a resin composition containing a polymerizable compound.

[0020] Another embodiment of the present disclosure provides a display device comprising a display panel and the above-described glass substrate or glass laminate disposed on the observer side of the display panel.

[0021] Other embodiments of this disclosure provide electronic equipment comprising the display device described above.

[0022] Another embodiment of the present disclosure provides a method for manufacturing a glass laminate, comprising: a preparation step of preparing a glass substrate which is chemically strengthened glass and has a thickness of 15 μm or more and 100 μm or less; a resin layer formation step of forming a resin layer on at least one of the first surface and the second surface of the glass substrate; and a cutting step of cutting the laminate having the glass substrate and the resin layer after the resin layer formation step.

[0023] The method for manufacturing a glass laminate in this disclosure preferably includes a processing step of processing the cut surface of the glass substrate so that the maximum height Sz of the cut surface of the glass substrate is 1.5 μm or less.

[0024] The method for manufacturing a glass laminate in this disclosure may further include a second resin layer forming step in which the side surface of the glass substrate is covered with a second resin layer after the cutting step. [Effects of the Invention]

[0025] This disclosure offers the advantage of providing glass substrates and glass laminates with good flexibility. [Brief explanation of the drawing]

[0026] [Figure 1] This is a schematic cross-sectional view illustrating an example of a glass substrate in this disclosure. [Figure 2] This is a schematic cross-sectional view illustrating an example of a glass substrate in this disclosure. [Figure 3] This is a schematic perspective view illustrating an example of a glass substrate in this disclosure. [Figure 4] This graph illustrates the profile of potassium concentration distribution. [Figure 5] This is a schematic diagram illustrating the U-shaped flexion test. [Figure 6] This is a schematic cross-sectional view illustrating a glass laminate in this disclosure. [Figure 7] This is a schematic cross-sectional view illustrating a glass laminate in this disclosure. [Figure 8] This is a schematic cross-sectional view illustrating a glass laminate in this disclosure. [Figure 9] This is a schematic cross-sectional view illustrating a glass laminate in this disclosure. [Figure 10] This is a schematic cross-sectional view illustrating a glass laminate in this disclosure. [Figure 11] This is a schematic cross-sectional view illustrating a glass laminate in this disclosure. [Figure 12] This is a schematic cross-sectional view illustrating a glass laminate in this disclosure. [Figure 13] This is a schematic cross-sectional view illustrating a display device in this disclosure. [Figure 14] This is a process diagram illustrating the manufacturing method of the glass laminate described in this disclosure. [Figure 15] This is a process diagram illustrating the manufacturing method of the glass laminate described in this disclosure. [Figure 16] This is a color image of a non-contact surface and layer cross-sectional shape measurement system for a comparative example of a glass substrate. [Figure 17] This is a color image of the non-contact surface and layer cross-sectional shape measurement system for a glass substrate in the example. [Figure 18]This is an explanatory diagram illustrating the method for measuring the maximum height Sz. [Modes for carrying out the invention]

[0027] Embodiments of this disclosure will be described below with reference to drawings and other figures. However, this disclosure can be implemented in many different ways and should not be interpreted as being limited to the embodiments described below. In addition, in order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and should not limit the interpretation of this disclosure. Furthermore, in this specification and each figure, elements similar to those described above with respect to previously shown figures will be denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0028] In this specification, when describing a configuration in which one component is placed on top of another component, unless otherwise specified, the terms "on top" or "below" include both cases: one where the other component is placed directly above or below the component in contact with it, and another where the other component is placed above or below the component via yet another component. Furthermore, when describing a configuration in this specification in which one component is placed on the surface of another component, unless otherwise specified, the terms "on the surface" or "on the surface" include both cases: one where the other component is placed directly above or below the component in contact with it, and another where the other component is placed above or below the component via yet another component.

[0029] The following describes in detail the glass substrate, glass laminate, display device, electronic device, and method for manufacturing the glass laminate as described in this disclosure.

[0030] A. Glass substrate The glass substrate in this disclosure has a first surface (which may be referred to as the first main surface), a second surface (which may be referred to as the second main surface) facing the first main surface, and a side surface, wherein the thickness is less than or equal to a predetermined value, and the maximum height Sz of the side surface is less than or equal to a predetermined value.

[0031] Figure 1 is a schematic cross-sectional view showing an example of a glass substrate in this disclosure. As shown in Figure 1, the glass substrate 1 has a first main surface 1A, a second main surface 1B facing the first main surface 1A, and a side surface 1C, and its thickness is less than or equal to a predetermined value, and the maximum height Sz of the side surface 1C is less than or equal to a predetermined value.

[0032] The glass substrate in this disclosure is thin, with a thickness below a predetermined value, and therefore highly flexible, allowing for improved bending resistance. On the other hand, the glass substrate is prone to microcracks during processing, particularly at the edges of the glass substrate during cutting. When microcracks are present in the glass substrate, cracks are more likely to occur starting from these microcracks. Furthermore, while chemically strengthened glass can be used as the glass substrate to improve bending resistance and impact resistance, even in this case, when cutting a large glass substrate made of chemically strengthened glass, the compressive stress layer formed on the surface of the chemically strengthened glass is absent at the cut surface, i.e., the side surface of the glass substrate, resulting in reduced strength at the side surface.

[0033] In contrast, in this disclosure, since the maximum height Sz of the side surface of the glass substrate is less than or equal to a predetermined value, the smoothness of the side surface of the glass substrate is high, microcracks on the side surface of the glass substrate can be reduced, and as a result, the strength of the side surface of the glass substrate can be increased. Therefore, when the glass substrate is bent, cracking from the side surface of the glass substrate can be suppressed, and the bending resistance can be improved. Furthermore, the impact resistance at the edges of the glass substrate can also be improved.

[0034] Therefore, in this disclosure, it is possible to use a glass substrate with good flexibility. Thus, the glass substrate in this disclosure can be bent and used in a wide variety of display devices, for example, it can be used as a component for a foldable display.

[0035] In this specification, the "side surface" of the glass substrate refers to all surfaces of the glass substrate other than the first and second main surfaces. Furthermore, for example, if the glass substrate is chamfered, the side surface of the glass substrate may have a chamfered portion. Specifically, as shown in Figure 2, the side surface 1C of the glass substrate 1 may have a side surface portion 2a and a chamfered portion 2b.

[0036] The thickness of the glass substrate is 15 μm or more and 100 μm or less, more preferably 20 μm or more and 90 μm or less, and even more preferably 25 μm or more and 80 μm or less. By making the glass substrate thin, as described above, good flexibility and sufficient hardness can be obtained. Furthermore, curling of the glass substrate can be suppressed. In addition, it is preferable in terms of reducing the weight of the glass substrate.

[0037] The maximum height Sz of the side surface of the glass substrate is 1.5 μm or less, preferably 1.0 μm or less. By ensuring the maximum height Sz of the side surface of the glass substrate is within the above range, the smoothness of the side surface is high, which suppresses cracking of the glass substrate when it is bent, thereby improving its flexibility. Furthermore, it improves the impact resistance at the edges of the glass substrate. On the other hand, the maximum height Sz of the side surface of the glass substrate is preferably 0.005 μm or more. If Sz is less than 0.005 μm, poor adhesion may make it difficult to coat the edges. Therefore, the maximum height Sz of the side surface of the glass substrate is preferably within the range of 0.005 μm to 1.5 μm.

[0038] Here, the maximum height Sz is a value measured in accordance with ISO 25178. The maximum height Sz can be measured using an optical interferometry non-contact surface shape measuring device. As an optical interferometry non-contact surface shape measuring device, for example, the VertScan2.0 R5500GML-A150-AC non-contact surface / layer cross-sectional shape measurement system manufactured by Ryoka Systems Co., Ltd. can be used. Details of the measurement method for the maximum height Sz will be described in the Examples section below. In this disclosure, Sz is a parameter used to evaluate surface roughness, and is more effective than Rz, which represents line roughness, for evaluating irregular surface properties.

[0039] The shape of the glass substrate is usually a rectangular parallelepiped, or a hexahedron. Even when the glass substrate has been chamfered, for example, its shape can still be considered a rectangular parallelepiped, or roughly a hexahedron. In this case, the glass substrate has two main faces (a first main face and a second main face) and four sides. In such a case, the maximum height Sz of at least one of the four sides of the glass substrate must be within a predetermined range.

[0040] In particular, it is preferable that the maximum height Sz of two opposing sides of the four sides of the glass substrate is within a predetermined range. For example, as shown in Figures 3(a) and (b), when the glass substrate 1 is bent, cracks are likely to occur in the glass substrate 1 at the bent portion F1. Therefore, if the maximum height Sz of two sides of the four sides of the glass substrate that are substantially parallel to the bending direction D1 of the glass substrate 1 is within the above range, it is possible to suppress the occurrence of cracks at the bent portion when the glass substrate is bent and improve its bending resistance.

[0041] Furthermore, if the plan view shape of the glass substrate is rectangular, it is preferable that the maximum height Sz of two opposing sides out of the four sides of the glass substrate is within the above range. For example, as shown in Figures 3(a) and (b), when bending the glass substrate 1, the bending direction D1 of the glass substrate 1 is often made approximately parallel to the long side direction of the glass substrate because it is easier to bend. Therefore, if the maximum height Sz of two opposing sides out of the four sides of the glass substrate is within the above range, it is possible to suppress cracking at the bent part of the glass substrate when it is bent and improve its bending resistance.

[0042] Furthermore, for the reasons mentioned above, it is preferable that the maximum height Sz of the two sides of the glass substrate that are substantially parallel to the bending direction of the glass substrate is within the above range.

[0043] In particular, it is preferable that the maximum height Sz of all four sides of the glass substrate is within a predetermined range. This can further suppress cracking of the glass substrate when it is bent, thereby improving its flexibility. Furthermore, it can improve the impact resistance at the edges of the glass substrate.

[0044] The glass used to constitute the glass substrate is not particularly limited, but chemically strengthened glass is preferred. Chemically strengthened glass has better impact resistance and bending resistance compared to unstrengthened glass. Furthermore, chemically strengthened glass has excellent mechanical strength, which is preferable because it allows for thinner construction.

[0045] Chemically strengthened glass is glass whose mechanical properties have been enhanced by a chemical method, specifically by partially exchanging sodium ions for potassium ions near the surface of the glass. It has a compressive stress layer on its surface. In other words, chemically strengthened glass has a high potassium content on its surface, resulting in compressive stress on the surface.

[0046] One method for confirming that a glass is chemically strengthened is to measure the concentration distribution of potassium in the depth direction from the surface of the glass. Specifically, it is preferable that a chemically strengthened glass is one in which, in the potassium concentration distribution in the thickness direction of the side surface of the glass substrate, when each region is divided into 10 equal parts in the thickness direction, and these regions are numbered from the 1st region to the 10th region in order from the 1st main surface side to the 2nd main surface side of the glass substrate, the average value of the potassium concentration in the 1st region is 2.0 or higher.

[0047] Here, "the order from the first face to the second face" means that the regions are numbered in order from the first face, that is, from the first face, they are the first region, the second region, and the third region.

[0048] In this case, the potassium concentration distribution in the thickness direction on the side surface of a glass substrate can be measured, for example, by energy-dispersive X-ray spectroscopy (EDX). Specifically, when measuring the potassium concentration distribution in the thickness direction on the side surface of a glass substrate using energy-dispersive X-ray spectroscopy (EDX), an Oxford Instruments X-MaxN can be used to perform EDX mapping in the thickness direction on the side surface of the glass substrate at an acceleration voltage of 10 kV, thereby quantifying the potassium concentration.

[0049] Furthermore, the average potassium concentration in the first region can be determined by the following method, based on the potassium concentration distribution in the thickness direction on the side surface of the glass substrate obtained by the method described above.

[0050] First, in the potassium concentration distribution in the thickness direction on the side surface of the glass substrate, each region obtained by dividing the thickness direction into ten equal parts is designated as region 1 to region 10, starting from the first main surface side of the glass substrate and moving towards the second main surface side. Then, the arithmetic mean of the potassium concentration measurements taken every 0.2 μm in the thickness direction in region 1 is taken as the average potassium concentration in region 1.

[0051] As described above, the shape of the glass substrate is usually a rectangular parallelepiped, or a hexahedron. Furthermore, even when the glass substrate is chamfered, for example, the shape of the glass substrate can still be considered to be a rectangular parallelepiped, or generally a hexahedron. In this case, the glass substrate has two main faces (a first main face and a second main face) and four sides. In this disclosure, when the glass substrate is chemically strengthened glass, it is preferable that only the two main faces (the first main face and the second main face) are chemically strengthened to have a compressive stress layer. That is, when the glass substrate is chemically strengthened glass, it is preferable that it is two-sided strengthened glass.

[0052] Generally, when a glass substrate is tempered on both sides, there is no compressive stress layer on the sides of the glass substrate, resulting in reduced strength on the sides. In contrast, in this disclosure, the maximum height Sz of the sides of the glass substrate is less than or equal to a predetermined value, resulting in high smoothness on the sides of the glass substrate and a reduction in microcracks on the sides of the glass substrate. As a result, the strength of the sides of the glass substrate can be increased. Therefore, when the glass substrate is bent, cracking from the sides of the glass substrate can be suppressed, and the bending resistance can be improved. Furthermore, the impact resistance at the edges of the glass substrate can also be improved. Thus, when the glass substrate is tempered on both sides, high impact resistance and bending resistance can be achieved by setting the maximum height Sz of the sides of the glass substrate to less than or equal to a predetermined value.

[0053] In this specification, chemically strengthened glass having a compressive stress layer due to chemical strengthening treatment being applied to only two main surfaces (first and second main surfaces) of the glass plate is referred to as "two-sided strengthened glass," and chemically strengthened glass having a compressive stress layer due to chemical strengthening treatment being applied to the entire surface of the glass plate (all six surfaces if the glass substrate is rectangular) is referred to as "six-sided strengthened glass." Two-sided strengthened glass can be obtained, for example, by chemically strengthening the glass substrate and then cutting it to the desired size. On the other hand, six-sided strengthened glass can be obtained, for example, by chemically strengthening the glass substrate.

[0054] When the glass substrate is tempered glass on two sides, the potassium concentration on the first and second main surfaces of the glass substrate is higher than the potassium concentration in the center of the side surface in the thickness direction.

[0055] In the above case, the potassium concentrations on the first and second main surfaces of the glass substrate are not particularly limited and are set appropriately according to the desired properties. Similarly, the potassium concentration in the center of the thickness direction of the side surface of the glass substrate is not particularly limited and is set appropriately according to the desired properties. For example, the potassium concentration in the center of the thickness direction of the side surface of the glass substrate may be zero.

[0056] Furthermore, in the case of a glass substrate that is tempered on two sides, in the glass substrate, if the potassium concentration distribution in the thickness direction of the side surface of the glass substrate is divided into ten equal regions in the thickness direction, and these regions are numbered from the 1st region to the 10th region in order from the 1st main surface side to the 2nd main surface side of the glass substrate, then the average potassium concentration in the 1st region will be higher than the average potassium concentration in the 5th region.

[0057] In the above case, the ratio of the average potassium concentration in the fifth region to the average potassium concentration in the first region is preferably 0.7 or less, and may be 0.5 or less. The lower limit is 0 or greater. If the above ratio is within the above range, the glass substrate can be said to be two-sided tempered glass. As described above, this disclosure is useful when the glass substrate is two-sided tempered glass, and when the above ratio is within the above range, high impact resistance and bending resistance can be achieved simultaneously by setting the maximum height Sz of the side surface of the glass substrate to a predetermined value or less.

[0058] In the above case, the potassium concentration in each region from the 1st to the 10th region is not particularly limited and is set appropriately according to the desired characteristics.

[0059] As mentioned above, the potassium concentration distribution in the thickness direction on the side surface of a glass substrate can be measured, for example, by energy-dispersive X-ray spectroscopy (EDX).

[0060] Furthermore, the average potassium concentration in the first region and the average potassium concentration in the fifth region can be determined by the following method, based on the potassium concentration distribution in the thickness direction of the side surface of the glass substrate obtained by the method described above. First, in the potassium concentration distribution in the thickness direction of the side surface of the glass substrate, each region, which is divided into ten equal parts in the thickness direction, is designated as the 1st to 10th regions, starting from the first main surface side of the glass substrate and moving towards the second main surface side. Then, the arithmetic mean of the measured potassium concentration values ​​at 0.2 μm intervals in the thickness direction in the first region is taken as the average potassium concentration in the first region. Similarly, the arithmetic mean of the measured potassium concentration values ​​at 0.2 μm intervals in the thickness direction in the fifth region is taken as the average potassium concentration in the fifth region.

[0061] For example, Figures 4(a) and 4(b) show examples of potassium concentration distribution profiles in the thickness direction on the side surface of a glass substrate. In the potassium concentration distribution profiles shown in Figures 4(a) and 4(b), each region, which is divided into ten equal parts in the thickness direction of the glass substrate, is designated as the 1st region 3A to the 10th region 3J, starting from the 1st main surface side of the glass substrate and moving towards the 2nd main surface side. The average potassium concentration in the 1st region 3A and the average potassium concentration in the 5th region 3E are then calculated. Note that if the glass substrate is two-sided tempered glass, a potassium concentration distribution like that shown in Figures 4(a) and 4(b) can be obtained. On the other hand, if the glass substrate is six-sided tempered glass, a potassium concentration distribution like that shown in Figure 4(c) can be obtained.

[0062] Examples of glass materials that make up chemically strengthened glass substrates include aluminosilicate glass, soda-lime glass, borosilicate glass, lead glass, alkali barium glass, and aluminoborsilicate glass.

[0063] Examples of commercially available chemically strengthened glass substrates include Corning's Gorilla Glass, AGC's Dragontrail, and Schott's chemically strengthened glass.

[0064] The glass substrate in this disclosure preferably has flexibility. Specifically, the flexibility of the glass substrate can be evaluated by performing the U-shaped bending test described below.

[0065] The U-shaped bending test is performed as follows. First, a test piece of glass substrate measuring 20 mm × 100 mm is prepared. Next, as shown in Figure 5(a), the short side portion 1P of the glass substrate 1 and the short side portion 1Q opposite to short side portion 1P are fixed with parallel fixing portions 100A and 100B, respectively. As shown in Figure 5(a), fixing portion 100B is slidable horizontally. Next, as shown in Figure 5(b), the glass substrate 1 is bent into a U-shape by moving fixing portion 100B closer to fixing portion 100A. Furthermore, as shown in Figure 5(c), the distance d between the two opposing short sides 1P and 1Q fixed by fixing portions 100A and 100B of the glass substrate 1 is gradually reduced by moving fixing portion 100B until a crack or fracture occurs in the glass substrate 1. In this case, the bending test is performed so that the bent portion 1R of the glass substrate 1 does not protrude from the lower ends of the fixed portions 100A and 100B. For example, if the distance d between two opposing short sides 1P and 1Q is 10 mm, the outer diameter of the bent portion 1R is considered to be 10 mm.

[0066] In the U-shaped bending test described above, the distance d between the opposing short sides 1P and 1Q of the glass substrate 1 at the time of cracking or fracture is preferably 10 mm or less, more preferably 8 mm or less, and particularly preferably 5 mm or less. A smaller distance d between the opposing short sides 1P and 1Q of the glass substrate 1 indicates higher bending resistance.

[0067] Furthermore, the bending resistance of the glass substrate can also be evaluated by performing a dynamic bending test. In the dynamic bending test, the distance d between opposing short sides 1P and 1Q of the glass substrate 1 is set to a predetermined value in the U-shaped bending test described above, and the glass substrate is repeatedly bent.

[0068] In the above dynamic bending test, it is preferable that no cracks or fractures occur in the glass substrate when the glass substrate is repeatedly bent 180° 200,000 times such that the distance d between opposing short sides 1P and 1Q of the glass substrate 1 becomes 12 mm. Furthermore, reducing the thickness of the glass substrate can improve its flexibility.

[0069] For example, if the thickness of the glass substrate is 81 μm or more and 100 μm or less, it is preferable that no cracks or fractures occur in the glass substrate when the operation of bending the glass substrate 1 by 180° 200,000 times is repeated in the above dynamic bending test so that the distance d between opposing short sides 1P and 1Q of the glass substrate 1 becomes 12 mm.

[0070] Furthermore, for example, if the thickness of the glass substrate is 50 μm or more and 81 μm or less, it is preferable that no cracks or fractures occur in the glass substrate when the operation of bending the glass substrate 1 by 180° 200,000 times is repeated in the above dynamic bending test so that the distance d between opposing short sides 1P and 1Q of the glass substrate 1 becomes 10 mm.

[0071] Furthermore, for example, if the thickness of the glass substrate is 50 μm or less, it is preferable that no cracks or fractures occur in the glass substrate when the dynamic bending test described above is repeated 200,000 times in which the glass substrate is bent 180° so that the distance d between opposing short sides 1P and 1Q of the glass substrate 1 becomes 8 mm.

[0072] The method for manufacturing a glass substrate in this disclosure is not particularly limited as long as it can reduce the maximum height Sz of the side surface of the glass substrate to a predetermined value or less, but it is preferable to perform the chemical strengthening treatment and cutting process in that order. For example, when manufacturing a component for a display device using a glass substrate, by following this process order, the subsequent manufacturing process can be carried out without cutting the large glass substrate, thereby increasing production efficiency.

[0073] In a method for manufacturing a glass substrate, it is preferable to process the cut surface of the glass substrate so that the maximum height Sz of the cut surface of the glass substrate is less than or equal to a predetermined value. When processing the cut surface of the glass substrate in this way, for example, the glass substrate may be cut so that the maximum height Sz of the cut surface of the glass substrate is less than or equal to a predetermined value, or the cut surface of the glass substrate may be processed while cutting the glass substrate so that the maximum height Sz of the cut surface of the glass substrate is less than or equal to a predetermined value, or the cut surface of the glass substrate may be processed after cutting so that the maximum height Sz of the cut surface of the glass substrate is less than or equal to a predetermined value. Specifically, one method is to cut the glass substrate with a scribe, then polish the cut surface of the glass substrate with abrasive paper, and then polish it further with diamond abrasive grains. The particle size of the abrasive material in the abrasive paper is preferably 30 μm or less, and particularly preferably 15 μm. Furthermore, the abrasive material in the abrasive paper is not particularly limited. Furthermore, the particle size of the diamond abrasive grains is preferably 3 μm or less, and particularly preferably 1 μm.

[0074] The glass substrate in this disclosure can be used, for example, as a cover member for a display device. Specifically, the glass substrate in this disclosure can be used as a cover member for a display device used in electronic devices such as smartphones, tablet terminals, wearable devices, personal computers, televisions, digital signage, public information displays (PIDs), and in-vehicle displays. In particular, the glass substrate in this disclosure can be preferably used in flexible displays such as foldable displays, rollable displays, and bendable displays, and is more preferably used in foldable displays.

[0075] B. Glass laminate The glass laminate in this disclosure comprises the glass substrate described above and a resin layer disposed on at least one of the first main surface side and the second main surface side of the glass substrate.

[0076] Figure 6 is a schematic cross-sectional view showing an example of a glass laminate in this disclosure. As shown in Figure 6, the glass laminate 10 has a glass substrate 1 having a predetermined thickness and a resin layer 11 disposed on the first main surface 1A side of the glass substrate 1.

[0077] Figure 7 is a schematic cross-sectional view showing another example of a glass laminate in this disclosure. As shown in Figure 7, the glass laminate 10 comprises a glass substrate 1 having a predetermined thickness, a resin layer 11 disposed on the first main surface 1A side of the glass substrate 1, and a resin layer 12 disposed on the second main surface 1B side of the glass substrate 1.

[0078] In the glass laminate described herein, since it has the aforementioned glass substrate, its flexibility can be improved.

[0079] On the other hand, glass substrates are thin, with a thickness below a predetermined value, which raises concerns about their fragility and low impact resistance. In contrast, in the glass laminate according to this disclosure, a resin layer is arranged on at least one of the first main surface side and the second main surface side of the glass substrate. When an impact is applied to the glass laminate, the resin layer absorbs the impact, suppressing cracking of the glass substrate and improving impact resistance. Furthermore, the resin layer can suppress the scattering of glass fragments even if the glass substrate is damaged.

[0080] Therefore, this disclosure allows for a glass laminate with good flexibility and impact resistance. Furthermore, even if the glass substrate in the glass laminate breaks, the risk of injury to the human body can be reduced, resulting in a highly safe glass laminate.

[0081] Therefore, the glass laminate in this disclosure is foldable and can be used in a wide variety of display devices, for example, as a component for a foldable display.

[0082] The following describes the various components of the glass laminate in this disclosure.

[0083] 1. Glass substrate The glass substrate in this disclosure has a first main surface, a second main surface facing the first main surface, and a side surface, and its thickness is less than or equal to a predetermined value, and the maximum height Sz of the side surface is less than or equal to a predetermined value.

[0084] The glass substrate is the same as described in section "A. Glass Substrate" above, so its explanation is omitted here.

[0085] 2. Resin layer The resin layer in this disclosure is a layer disposed on at least one of the first main surface side and the second main surface side of the glass substrate. The resin layer can also function as an impact-absorbing layer having shock absorption properties, or as a shatterproof layer that suppresses the scattering of glass when the glass substrate breaks.

[0086] In this specification, when the glass laminate of this disclosure is used as a display device, the resin layer located on the observer side of the glass substrate may be referred to as the surface resin layer, and the resin layer located on the opposite side of the glass substrate from the surface resin layer may be referred to as the back resin layer.

[0087] (1) Characteristics of the resin layer The resin layer preferably has shock-absorbing properties. Specifically, the composite modulus of the resin layer is preferably 4.7 GPa or higher, and more preferably 5.7 GPa or higher. By having the composite modulus of the resin layer within the above range, cracking of the glass substrate due to impact can be suppressed, and impact resistance and scratch resistance can be improved.

[0088] The upper limit is 40 GPa or less, preferably 20 GPa or less, and particularly preferably 15 GPa or less. Specifically, the range of 40 GPa to 4.7 GPa is preferred, the range of 5.7 GPa to 20 GPa is particularly preferred, and the range of 5.7 GPa to 15 GPa is particularly preferred.

[0089] Furthermore, according to the composite modulus measurement method described later, the composite modulus of the glass substrate is approximately 40 GPa. Therefore, the composite modulus of the resin layer is preferably 40 GPa or less, and more preferably 20 GPa or less.

[0090] Here, the composite modulus of the resin layer is the indentation hardness (H) of the resin layer. IT The contact projected area A required when measuring ) p The calculation shall be performed using the following method. "Indentation hardness" is a value obtained from the load-displacement curve from loading to unloading of the indenter, which is obtained by hardness measurement using the nanoindentation method. The composite modulus of the resin layer is the modulus of elasticity that includes the elastic deformation of the resin layer and the elastic deformation of the indenter.

[0091] Indentation hardness (H IT The measurement of the glass laminate will be performed using a BRUKER TI950 TriboIndenter on the measurement sample. Specifically, first, a block will be prepared by embedding a 1mm x 10mm glass laminate in embedding resin, and from this block, uniform sections with a thickness of 50nm to 100nm, free from holes, etc., will be cut using a general sectioning method. For sectioning, an "Ultramicrotome EM UC7" (Leica Microsystems, Inc.) or similar can be used. The remaining block from which these uniform sections free from holes, etc., have been cut will be used as the measurement sample.

[0092] Next, in the cross-section obtained by cutting out the above section from the measurement sample, a Berkovich indenter (triangular pyramidal, TI-0039 manufactured by BRUKER) is pressed vertically into the center of the cross-section of the resin layer over 10 seconds to a maximum indentation load of 25 μN, under the following measurement conditions. Here, in order to avoid the influence of the glass substrate and the side edges of the resin layer, the Berkovich indenter is pressed into the portion of the resin layer 500 nm away from the interface between the glass substrate and the resin layer toward the center of the resin layer, and 500 nm away from both ends of the resin layer toward the center of the resin layer.

[0093] In the case where an arbitrary layer such as a functional layer exists on the surface of the resin layer opposite to the surface on the glass substrate side, it shall be pushed into the portion of the resin layer 500 nm away from the interface between the arbitrary layer and the resin layer toward the center side of the resin layer. After that, it shall be held for a certain period to relieve the residual stress, and then unloaded over 10 seconds, and the maximum load after relaxation shall be measured, and the maximum load P max (μN) and the contact projected area A p (nm 2 ) are used, and P max / A p is used to calculate the indentation hardness (H IT ). The contact projected area is the contact projected area obtained by correcting the curvature of the indenter tip by the Oliver-Pharr method using a fused silica of a standard sample (5-0098 manufactured by BRUKER).

[0094] The indentation hardness (H IT ) shall be the arithmetic mean value of the values obtained by measuring at 10 locations. In the case where there are measured values that deviate from the arithmetic mean value by more than ±20%, those measured values shall be excluded and re-measured. Whether or not there are measured values that deviate from the arithmetic mean value by more than ±20% shall be determined by whether the value (%) obtained by (A - B) / B × 100 is more than ±20% when the measured value is A and the arithmetic mean value is B. The indentation hardness (H IT ) can be adjusted according to the type of resin contained in the resin layer described later, etc.

[0095] (Measurement conditions) · Loading rate: 2.5 μN / second · Holding time: 5 seconds · Load unloading rate: 2.5 μN / second · Measurement temperature: 25 °C

[0096] The complex elastic modulus E r of the resin layer is obtained by the following mathematical formula (1) from the contact projected area A obtained when measuring the indentation hardness pThe composite modulus is determined by measuring the indentation hardness at 10 locations, calculating the composite modulus each time, and taking the arithmetic mean of the 10 obtained composite moduli.

[0097]

number

[0098] (In the above formula (1), A p This is the contact projection area, and E r (where S is the composite modulus of the resin layer, and S is the contact stiffness.)

[0099] (2) Thickness of the resin layer The thickness of the resin layer is not particularly limited as long as flexibility and shock absorption can be obtained. For example, it is preferably 5 μm or more and 60 μm or less, more preferably 10 μm or more and 50 μm or less, and even more preferably 15 μm or more and 40 μm or less. By making the resin layer relatively thin, as within the above range, flexibility can be increased, cracking of the resin layer can be suppressed when the glass laminate is bent, and bending resistance can be maintained.

[0100] Here, the thickness of the resin layer can be the average value of any 10 thicknesses obtained by measuring the cross-section in the thickness direction of the glass laminate as observed by a transmission electron microscope (TEM), scanning electron microscope (SEM), or scanning transmission electron microscope (STEM). Unless otherwise specified, the same method can be used to measure the thickness of other layers in the glass laminate.

[0101] (3) Materials of the resin layer (a) resin The resin included in the resin layer is not particularly limited as long as it is a resin that can produce a resin layer having transparency and shock absorption properties, but it is preferable that it is a resin that satisfies the above-mentioned composite elastic modulus. Specifically, examples include polyimide resins, epoxy resins, polyesters, polyurethanes, acrylic resins, etc. These resins may be used individually or in combination of two or more.

[0102] In this specification, polyimide resin refers to a polymer having imide bonds in its main chain. Examples of polyimide resins include polyimide, polyamideimide, polyesterimide, and polyetherimide. The following explanation will use polyimides and polyamideimides as examples.

[0103] (i) Polyimide Polyimides are obtained by reacting a tetracarboxylic acid component with a diamine component. It is preferable to obtain polyamic acid by polymerization of the tetracarboxylic acid component and the diamine component and then imidate it. Imidation may be carried out by chemical imidation, thermal imidation, or a combination of chemical and thermal imidation.

[0104] The polyimide is not particularly limited as long as it satisfies the above-mentioned composite modulus and is transparent, but it is preferable that it contains, for example, 10 mol% to 100 mol% of the constituent unit represented by the following general formula (1) and (100-x) mol% of the constituent unit represented by the following general formula (2) (where x is the mole percentage of the constituent unit represented by the above general formula (1)), and has a weight-average molecular weight of 100,000 or more. This is because the polyimide has a specific structure in which a parabiphenylene group with a twisted dihedral angle via an ester bond is contained in the main chain, and a diamine residue having an aromatic ring or an aliphatic ring, and has a specific weight-average molecular weight, which makes it easier to achieve a good balance between the composite modulus and flexural resistance.

[0105] [ka]

[0106] (In general formulas (1) and (2), R 1 ~R 4 Each of these independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R 1 and R 2 At least one of the following, and R 3 and R 4 At least one of them represents an alkyl group having 1 to 6 carbon atoms. A represents a tetravalent group that is a tetracarboxylic acid residue having an aromatic or aliphatic ring, and B represents a divalent group that is a diamine residue having an aromatic or aliphatic ring.

[0107] Here, a tetracarboxylic acid residue refers to a residue obtained by removing four carboxyl groups from a tetracarboxylic acid, and represents the same structure as a residue obtained by removing the acidic dianhydride structure from a tetracarboxylic dianhydride. A diamine residue refers to a residue obtained by removing two amino groups from a diamine.

[0108] In general formula (1), R 1 and R 2 At least one of the following, as well as R 3 and R 4 At least one of the C1-C6 alkyl groups represents an alkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms may be a linear or branched alkyl group, and examples include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, and an n-hexyl group. From the viewpoint of solvent solubility, an alkyl group having 1 to 4 carbon atoms is preferred, more preferably an alkyl group having 1 to 2 carbon atoms, and more preferably a methyl group. In addition, from the viewpoint of solvent solubility, R 1 and R 2 , and R 3 and R 4 However, it is preferable to represent a methyl group.

[0109] In general formula (1), B represents a divalent group which is a diamine residue having an aromatic ring or an aliphatic ring. The diamine residue having an aromatic ring or an aliphatic ring can be a residue obtained by removing two amino groups from a diamine having an aromatic ring or a diamine having an aliphatic ring.

[0110] Specific examples of diamines having aromatic rings and diamines having aliphatic rings can be found in, for example, Japanese Patent Publication No. 2019-132930 and Japanese Patent Publication No. 2019-1989. These can be used individually or in combination of two or more types.

[0111] In the above general formula (2), A represents a tetravalent group which is a tetracarboxylic acid residue having an aromatic or aliphatic ring, and B represents a divalent group which is a diamine residue having an aromatic or aliphatic ring. B in the above general formula (2) may be the same as B in the above general formula (1), so the explanation is omitted here. B in the above general formula (1) and B in the above general formula (2) may be the same or different.

[0112] The tetracarboxylic acid residue in A of the above general formula (2) can be a residue obtained by removing the acid dianhydride structure from a tetracarboxylic acid dianhydride having an aromatic ring, or a residue obtained by removing the acid dianhydride structure from a tetracarboxylic acid dianhydride having an aliphatic ring.

[0113] Specific examples of tetracarboxylic dianhydrides having aromatic rings and tetracarboxylic dianhydrides having aliphatic rings can be found in, for example, Japanese Patent Publication No. 2019-132930 and Japanese Patent Publication No. 2019-1989. These can be used individually or in combination of two or more types.

[0114] The polyimide preferably contains 10 mol% to 100 mol% of the constituent units represented by the above general formula (1). From the viewpoint of solubility in solvents, the polyimide is more preferably containing 15 mol% or more of the constituent units represented by the above general formula (1), even more preferably 25 mol% or more, and particularly preferably 50 mol% or more.

[0115] On the other hand, copolymer components may be included to improve surface hardness and transparency, and the polyimide may contain 95 mol% or less of the constituent units represented by the above general formula (1), 90 mol% or less, or 80 mol% or less.

[0116] Furthermore, it is preferable that the polyimide contains (100-x) mol% of the constituent units represented by the above general formula (2) (where x is the mol% of the constituent units represented by the above general formula (1)). From the viewpoint of solubility in solvents, it is more preferable that the polyimide contains 85 mol% or less of the constituent units represented by the above general formula (2), even more preferable that it contains 75 mol% or less, and particularly preferable that it contains 50 mol% or less.

[0117] Furthermore, if the polyimide contains 100 mol% of the constituent units represented by the above general formula (1), then the constituent units represented by the above general formula (2) are 0 mol%, i.e., not included. The constituent units represented by the above general formula (2) may be 0 mol%, but they may also be included as copolymer components from the viewpoint of improving surface hardness and transparency, and the polyimide may contain 5 mol% or more, 10 mol% or more, or 20 mol% or more of the constituent units represented by the above general formula (2).

[0118] From the viewpoint of improving transparency and surface hardness, it is preferable that at least one of the tetravalent group, which is a tetracarboxylic acid residue of A, and the divalent group, which is a diamine residue of B, contains an aromatic ring and includes at least one selected from the group consisting of (i) a fluorine atom, (ii) an aliphatic ring, and (iii) an alkylene group which may be substituted with a sulfonyl group or fluorine. When polyimide contains at least one selected from a tetracarboxylic acid residue having an aromatic ring and a diamine residue having an aromatic ring, the molecular skeleton becomes rigid, the orientation is increased, and the surface hardness is improved. However, a rigid aromatic ring skeleton tends to have an extended absorption wavelength and tends to reduce transmittance in the visible light region.

[0119] On the other hand, if polyimide (i) contains a fluorine atom, its transparency is improved because it makes it more difficult for charge to move within the polyimide framework. Also, if polyimide (ii) contains an aliphatic ring, its transparency is improved because it breaks the conjugation of π electrons within the polyimide framework, thereby inhibiting charge movement within the framework. Furthermore, if polyimide (iii) contains a structure in which aromatic rings are linked by sulfonyl groups or alkylene groups which may be substituted with fluorine, its transparency is improved because it breaks the conjugation of π electrons within the polyimide framework, thereby inhibiting charge movement within the framework.

[0120] In particular, from the viewpoint of improving transparency and surface hardness, it is preferable that at least one of the tetravalent group, which is a tetracarboxylic acid residue of A, and the divalent group, which is a diamine residue of B, contains an aromatic ring and a fluorine atom, and it is preferable that the divalent group, which is a diamine residue of B, contains an aromatic ring and a fluorine atom.

[0121] Polyimide is selected from the viewpoints of transparency, flexibility, and surface hardness, such that the diamine residue having an aromatic ring or aliphatic ring in B of the above general formulas (1) and (2) is a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexanediamine residue, a 4,4'-diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, a 2,2-bis(4-aminophenyl)propane residue, or a 3,3'-bis(trifluoromethyl)-4,4'-[ Preferably, the group is at least one divalent group selected from the group consisting of (1,1,1,3,3,3-hexafluoropropane-2,2-diyl)bis(4,1-phenyleneoxy)]dianiline residue, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane residue, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane residue, and a divalent group represented by the following general formula (3).

[0122] In particular, from the viewpoint of achieving both transparency and surface hardness, it is preferable that the group consists of at least one divalent group selected from the group consisting of a 4,4'-diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, a 2,2-bis(4-aminophenyl)propane residue, and a divalent group represented by the following general formula (3), and more preferably a divalent group represented by the following general formula (3). As for the divalent group represented by the following general formula (3), R 5 and R 6 It is more preferable that is a perfluoroalkyl group, and among these, a perfluoroalkyl group having 1 to 3 carbon atoms is preferred, and more preferably a trifluoromethyl group or a perfluoroethyl group. Also, R in the following general formula (3) 5 and R 6 The alkyl group in is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group or an ethyl group.

[0123] [ka]

[0124] (In general formula (3), R 5 and R 6 Each of these independently represents a hydrogen atom, an alkyl group, or a perfluoroalkyl group.

[0125] Polyimides, in particular, are selected based on their transparency, flexibility, and surface hardness. Specifically, the tetracarboxylic acid residues having aromatic or aliphatic rings in A of the above general formula (2) are cyclohexanetetracarboxylic acid dianhydride residues, cyclopentanetetracarboxylic acid dianhydride residues, dicyclohexane-3,4,3',4'-tetracarboxylic acid dianhydride residues, cyclobutanetetracarboxylic acid dianhydride residues, pyromellitic acid dianhydride residues, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride residues, and 2,2',3,3' Preferably, it is at least one tetravalent group selected from the group consisting of -biphenyltetracarboxylic dianhydride residue, 2,3,3',4'-biphenyltetracarboxylic dianhydride residue, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride residue, 3,4'-(hexafluoroisopropylidene)diphthalic anhydride residue, 3,3'-(hexafluoroisopropylidene)diphthalic anhydride residue, 4,4'-oxydiphthalic anhydride residue, and 3,4'-oxydiphthalic anhydride residue.

[0126] In the above general formula (2), A preferably contains a total of 50 mol% or more of these preferred residues, more preferably 70 mol% or more, and even more preferably 90 mol% or more.

[0127] In the above general formula (2), A preferably includes a group of tetracarboxylic acid residues (group A) suitable for improving rigidity, such as at least one selected from the group consisting of pyromellitic dianhydride residues, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride residues, and 2,2',3,3'-biphenyltetracarboxylic acid dianhydride residues, from the viewpoint of improving surface hardness. Furthermore, as A in the above general formula (2), it is preferable that, from the viewpoint of improving transparency, A includes a group of tetracarboxylic acid residues suitable for improving transparency (group B), such as at least one selected from the group consisting of cyclohexanetetracarboxylic acid dianhydride residue, cyclopentanetetracarboxylic acid dianhydride residue, dicyclohexane-3,4,3',4'-tetracarboxylic acid dianhydride residue, cyclobutanetetracarboxylic acid dianhydride residue, 2,3,3',4'-biphenyltetracarboxylic acid dianhydride residue, 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride residue, 3,4'-(hexafluoroisopropylidene)diphthalic acid anhydride residue, 3,3'-(hexafluoroisopropylidene)diphthalic acid anhydride residue, 4,4'-oxydiphthalic acid anhydride residue, and 3,4'-oxydiphthalic acid anhydride residue. Group A and group B may be used in combination.

[0128] When mixing Group A and Group B, the content ratio of the tetracarboxylic acid residue group suitable for improving rigidity (Group A) and the tetracarboxylic acid residue group suitable for improving transparency (Group B) is preferably 0.05 moles to 9 moles, more preferably 0.1 moles to 5 moles, and even more preferably 0.3 moles to 4 moles, of the tetracarboxylic acid residue group suitable for improving rigidity (Group A) per mole of the tetracarboxylic acid residue group suitable for improving transparency (Group B).

[0129] In particular, from the viewpoint of improving surface hardness and transparency, it is preferable to use at least one of the following residues as Group B: a 4,4'-(hexafluoroisopropylidene)diphthalic anhydride residue containing a fluorine atom, and a 3,4'-(hexafluoroisopropylidene)diphthalic anhydride residue.

[0130] The content percentages (mol%) of each repeating unit, each tetracarboxylic acid residue, and each diamine residue in polyimide can be determined from the initial molecular weight during polyimide production. Furthermore, the content percentages (mol%) of each tetracarboxylic acid residue and each diamine residue in polyimide can be determined using high-performance liquid chromatography, gas chromatography-mass spectrometry, NMR, elemental analysis, XPS / ESCA, and TOF-SIMS on the decomposition products of the polyimide obtained in the same manner as described above.

[0131] From the standpoint of good flexural resistance, the polyimide is preferably of a weight-average molecular weight equivalent to 100,000 or more in terms of polystyrene in gel permeation chromatography. From the standpoint of flexural resistance, the weight-average molecular weight may be 120,000 or more, 140,000 or more, or 160,000 or more. On the other hand, from the standpoint of being less prone to the occurrence of bubble defects, the weight-average molecular weight is preferably 270,000 or less. Furthermore, from the standpoint of solubility, the weight-average molecular weight may be 250,000 or less, 230,000 or less, or 210,000 or less.

[0132] The weight-average molecular weight of polyimide can be measured by gel permeation chromatography (GPC). Specifically, the polyimide is used as a 0.1% by mass N-methylpyrrolidone (NMP) solution, and the developing solvent is a 30 mmol% LiBr-NMP solution with a water content of 500 ppm or less. The measurement is performed using a Tosoh GPC instrument (HLC-8120, column: SHODEX GPC LF-804) under the following conditions: sample input volume of 50 μL, solvent flow rate of 0.4 mL / min, and temperature of 37°C. The weight-average molecular weight is determined based on a polystyrene standard sample of the same concentration as the sample.

[0133] (ii) Polyamide-imide The polyamide-imide is not particularly limited as long as it satisfies the above-mentioned composite modulus and is transparent, but it is preferable to include, for example, a polyimide constituent unit containing a constituent unit represented by the following formula (4) and a polyamide constituent unit containing a constituent unit represented by the following formula (5).

[0134] [ka]

[0135] (In formula (5), X represents a divalent group which is a dicarboxylic acid residue having an aromatic ring.)

[0136] By including polyimide units containing the structural unit represented by formula (4) and polyamide units containing the structural unit represented by formula (5), a resin layer with high composite modulus and flexibility can be obtained while maintaining sufficient transparency. In the above polyimide, a polyamide structural unit is introduced that further includes a dicarboxylic acid residue having an aromatic ring, which promotes intermolecular interactions by hydrogen bonding, in addition to a polyimide structural unit having a specific structure of tetracarboxylic acid residues containing a parabiphenylene group with a dihedral angle twisted via an ester bond in the main chain and a specific diamine residue. It is presumed that by introducing an aromatic ring twist in the main chain structure of the polymer, intermolecular energy transitions occurring in π-conjugated polymers can be suppressed, and while achieving sufficient transparency, the introduction of amide bond sites and ester bond sites in the polyimide structural unit can enhance intermolecular forces due to hydrogen bond formation, thereby obtaining a resin layer with high composite modulus and flexibility.

[0137] Furthermore, the above-mentioned polyamide-imide exhibits particularly good flexural resistance even in high-humidity environments. In the above-mentioned polyamide-imide, hydrogen bonding is formed between the amide bond sites and the ester bond sites in the polyimide constituent units, thereby suppressing hydrogen bonding with moisture even in high-humidity environments. This is presumed to suppress the deterioration of flexural resistance in high-humidity environments, resulting in good flexural resistance.

[0138] Furthermore, since the polyamide-imide contains the structural unit represented by formula (4), it exhibits good solubility in solvents even when containing the structural unit represented by formula (4).

[0139] (Polyimide constituent units) Polyimide structural units are structural units obtained by reacting a tetracarboxylic acid component with a diamine component, and examples include the structural unit represented by the general formula (2) described in the section on polyimides above.

[0140] The constituent unit represented by formula (4) above can be obtained by reacting a tetracarboxylic dianhydride represented by formula (4-1) below with 2,2-bis(trifluoromethyl)-4,4-diaminobiphenyl.

[0141] [ka]

[0142] The content of the component represented by formula (4) above may be 100 mol% of the total polyimide component units in the polyamide-imide. Furthermore, the polyimide component units may contain other polyimide component units different from those represented by formula (4). The content of the component represented by formula (4) above is preferably 50 mol% or more, more preferably 60 mol% or more, even more preferably 70 mol% or more, preferably 100 mol% or less, and may also be 90 mol% or less. If the content of the component represented by formula (4) above is within the above range, it is possible to have sufficient transparency while also possessing high composite modulus and flexural resistance. Other polyimide component units different from those represented by formula (4) above may be included to improve the balance between transparency, composite modulus, and flexural resistance, or to add further properties.

[0143] The content of the tetracarboxylic dianhydride residue represented by formula (4-1) in polyamide-imide is preferably 50 mol% or more, more preferably 60 mol% or more, even more preferably 70 mol% or more, preferably 100 mol% or less, and may also be 90 mol% or less, relative to the total amount of tetracarboxylic acid residues contained in the polyimide constituent units. If the content of the tetracarboxylic dianhydride residue represented by formula (4-1) is within the above range, it is possible to have sufficient transparency while also having high composite modulus and flexural resistance. To improve the balance between transparency, composite modulus and flexural resistance, or to add further properties, other tetracarboxylic dianhydride residues different from the tetracarboxylic dianhydride residue represented by formula (4-1) may be included.

[0144] Other polyimide constituent units that may be included in the polyimide constituent units include, for example, polyimide constituent units represented by the general formula (2) above that are different from the constituent units represented by formula (4) above. In the constituent units represented by the general formula (2) above, A and B may be the same or different in each constituent unit. That is, in the constituent units represented by the general formula (2) above, A and B may each be included independently as one type or as two or more types.

[0145] In the constituent unit represented by the general formula (2) above, A represents a tetravalent group which is a tetracarboxylic acid residue having an aromatic ring or an aliphatic ring. Examples of A include tetravalent groups represented by the following formulas (a1) to (a7), and tetravalent groups in which some or all of the hydrogen atoms in the tetravalent group represented by these formulas are substituted with one or more substituents selected from the group consisting of a fluoro group, a methyl group, a methoxy group, a trifluoromethyl group, or a trifluoromethoxy group.

[0146] [ka]

[0147] (In equations (a1) to (a7), * represents a bond, Q aThese are single bonds, -O-, -S-, -CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -CO-, -SO2-, -Ph-, -Ph-Q a2 -Ph-, -Q a2 -Ph-Q a2 -, -Q a2 -Ph-Ph-Q a2 -, -Q a2 -Ph-Q a2 -Ph-Q a2 - represents a fluorene group. Ph represents a phenylene group, Q a2 (This represents -O-, -S-, -CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -CO-, or -SO2-.)

[0148] Q a The bonding position to each ring can be either ortho or meta relative to one of the two carboxyl groups bonded to each ring. a2 The bonding position to each ring is preferably independently at the meta or para position relative to the phenylene group, and more preferably at the para position.

[0149] In the constituent unit represented by the general formula (2) above, as A, among the tetravalent groups represented by formulas (a1) to (a7) above, in the case of structures containing aromatic rings as in formulas (a1) to (a3) ​​above, the tetravalent groups represented by formulas (a1) and (a2) above are preferred from the viewpoint of providing transparency and solubility in solvents. Furthermore, it is preferable to have a structure that can be bent between the aromatic rings, and Q in formula (a2) above is preferred. a Examples include -O-, -S-, -CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -SO2-, and -Q a2 -Ph-Q a2 -(Q a2 Q represents -O-, -S-, -CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -CO-, or -SO2-. It is preferable that it is Q. Furthermore, since transparency is improved when a fluorine atom is included, a For example, -C(CF3)2-, -Qa2 -Ph-Q a2 -(Q a2 -C(CF3)2-) is preferred, and from the viewpoint of the composite modulus, Q a Among these, -C(CF3)2- is more preferable.

[0150] Furthermore, in the constituent unit represented by the general formula (2) above, among the tetravalent groups represented by formulas (a1) to (a7) above, A is preferred when it includes an aliphatic ring as in formulas (a4) to (a7) above, because it has an aliphatic structure and therefore excellent transparency and solubility. In particular, tetravalent groups represented by structures (a4), (a5), or (a6) with few bending sites are preferred because they result in a good composite elastic modulus, and among these, the tetravalent group represented by (a4) is preferred.

[0151] In the constituent unit represented by the general formula (2) above, B represents a divalent group which is a diamine residue having an aromatic ring or an aliphatic ring. Examples of B include divalent groups represented by the following formulas (b1) to (b6), and divalent groups in which some or all of the hydrogen atoms in the divalent group represented by these formulas are substituted with one or more substituents selected from the group consisting of a fluoro group, a methyl group, a methoxy group, a trifluoromethyl group, or a trifluoromethoxy group.

[0152] [ka]

[0153] (In equations (b1) to (b6), * represents a bond, Q b These are single bonds, -O-, -S-, -CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -CO-, -SO2-, -Ph-, -Ph-Q b2 -Ph-, -Q b2 -Ph-Q b2 -, -Q b2 -Ph-Ph-Q b2 -, -Q b2 -Ph-Q b2 -Ph-Q b2 - represents a fluorene group. Ph represents a phenylene group, Qb2 (This represents -O-, -S-, -CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -CO-, or -SO2-.)

[0154] Q b The bonding position to each ring is preferably independently at the meta or para position relative to the amino group bonded to each ring, and more preferably at the para position. b2 The bonding position to each ring is preferably independently at the meta or para position relative to the phenylene group, and more preferably at the para position.

[0155] In the constituent unit represented by the general formula (2) above, B is preferably a molecular structure in which the π-conjugation between phenylene groups is cleaved while having a phenylene skeleton, from the viewpoint of transparency and maintenance of the composite elastic modulus, and it is even more preferable that it contains fluorine.

[0156] As a molecular structure in which the π-conjugation between phenylene groups is cleaved, in the divalent group represented by the above formula (b2), Q b However, it is preferable that the molecule is -O-, -S-, -CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, or -SO2-, and more preferably -C(CF3)2- or -SO2-.

[0157] Furthermore, in the constituent unit represented by the general formula (2) above, B is preferably at least one divalent group selected from the group consisting of divalent groups represented by the general formula (3) above, from the viewpoint of transparency and maintenance of composite elastic modulus. As for the divalent group represented by the general formula (3) above, R is preferable from the viewpoint of transparency. 5 and R 6 It is more preferable that the group is a methyl group or a trifluoromethyl group, and even more preferable that it is a trifluoromethyl group from the viewpoint of transparency.

[0158] Furthermore, other polyimide constituent units, different from the constituent units represented by formula (4) above, may be the constituent units represented by the following formula (6).

[0159] [ka]

[0160] (In formula (6), B' represents a divalent group which is a diamine residue having an aromatic or aliphatic ring, and is different from the 2,2-bis(trifluoromethyl)-4,4-diaminobiphenyl residue.)

[0161] In formula (6) above, B' represents a diamine residue having an aromatic ring or an aliphatic ring, which is different from the 2,2-bis(trifluoromethyl)-4,4-diaminobiphenyl residue, and may be the same as B in general formula (5) above.

[0162] When polyimide constituent units include other polyimide constituent units, it is preferable to include the constituent unit represented by the following formula (7), the constituent unit represented by the following formula (8), or a combination thereof. Including the constituent unit represented by the following formula (7), the constituent unit represented by the following formula (8), or a combination thereof is preferable from the standpoint of improving transparency and increasing solubility in solvents. In particular, including the constituent unit represented by the following formula (7) is more preferable from the standpoint of improving transparency while maintaining a high composite modulus.

[0163] [ka]

[0164] The structural unit represented by formula (7) above can be obtained by reacting cyclobutanetetracarboxylic dianhydride with 2,2-bis(trifluoromethyl)-4,4-diaminobiphenyl. The structural unit represented by formula (8) above can be obtained by reacting 4,4'-(hexafluoroisopropylidene)diphthalic anhydride with 2,2-bis(trifluoromethyl)-4,4-diaminobiphenyl.

[0165] The total content of other polyimide constituent units, which are different from the constituent units represented by formula (4) above, relative to the total polyimide constituent units in the polyamide-imide may be 0 mol%, but if present, it is preferably 5 mol% or more, may be 10 mol% or more, preferably 50 mol% or less, more preferably 40 mol% or less, and even more preferably 30 mol% or less. If the total content of the other polyimide constituent units is within the above range, high transparency can be imparted and the composite elastic modulus will be good.

[0166] In particular, when the constituent unit represented by formula (7), the constituent unit represented by formula (8), or a combination thereof is included, the total content ratio of the constituent unit represented by formula (7) and the constituent unit represented by formula (8) relative to the total polyimide constituent units in the polyamide-imide is preferably 5 mol% or more, may be 10 mol% or more, preferably 50 mol% or less, more preferably 40 mol% or less, and even more preferably 30 mol% or less. If the total content ratio of the constituent unit represented by formula (7) and the constituent unit represented by formula (8) is within the above range, high transparency can be provided and the composite elastic modulus will be good.

[0167] (Polyamide constituent units) Polyamide structural units are structural units obtained by reacting a dicarboxylic acid component with a diamine component, and examples include structural units represented by the following general formula (9).

[0168] [ka]

[0169] (In general formula (9), X represents a divalent group that is a dicarboxylic acid residue having an aromatic ring, and B represents a divalent group that is a diamine residue having an aromatic or aliphatic ring.)

[0170] Here, a dicarboxylic acid residue refers to a residue obtained by removing two carboxyl groups from a dicarboxylic acid, and it has the same structure as a residue obtained by removing two carboxylic acid chloride groups from a dicarboxylic acid chloride. A diamine residue refers to a residue obtained by removing two amino groups from a diamine.

[0171] The polyamide constituent units in polyamide-imide include the constituent unit represented by formula (5) above as an essential component. One or more of the constituent units represented by formula (5) above are included in the polyamide constituent units.

[0172] The constituent unit represented by formula (5) above can be obtained by reacting a dicarboxylic acid component having an aromatic ring with 2,2-bis(trifluoromethyl)-4,4-diaminobiphenyl. Examples of dicarboxylic acid components include dicarboxylic acids and dicarboxylic acid chlorides, but from the viewpoint of reactivity, it is preferable to use dicarboxylic acid chlorides.

[0173] The constituent unit represented by formula (5) above preferably has at least one selected from the group consisting of structures represented by the following formulas (x1) to (x3) as X in formula (5). A resin layer with high composite elastic modulus can be obtained while having sufficient transparency. Furthermore, it may be a 1,3-phenylene group instead of the 1,4-phenylene group represented by the following formula (x1).

[0174] [ka]

[0175] (In equation (x3), L represents -O-, -S-, -CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, or -CO-, and * represents a bond.)

[0176] In the above formula (5), among the structures represented by formulas (x1) to (x3), the structure represented by formula (x1) or formula (x2) is more preferable, and the structure represented by formula (x2) is even more preferable, in terms of X.

[0177] The content of the constituent unit represented by formula (5) above may be 100 mol% relative to the total polyamide constituent units in the polyamide-imide. In addition, the polyamide constituent units may further contain other polyamide constituent units different from the constituent unit represented by formula (5) above. The content of the constituent unit represented by formula (5) above is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, preferably 100 mol% or less, and may be 95 mol% or less, relative to the total polyamide constituent units in the polyamide-imide. If the content of the constituent unit represented by formula (5) above is within the above range, a good balance between transparency and composite elastic modulus is obtained.

[0178] From the viewpoint of balancing transparency and composite modulus, the total content of one or more types of X selected from the group consisting of structures represented by formulas (x1) to (x3) in the polyamide-imide may be 100 mol%, preferably 80 mol% or more and 100 mol%, more preferably 90 mol% or more and 100 mol%, and even more preferably 95 mol% or more and 100 mol%.

[0179] The polyamide constituent units may include other polyamide constituent units different from the constituent units represented by formula (5) above. For example, a polyamide constituent unit different from the constituent unit represented by general formula (9) above may be included. In the constituent units represented by general formula (9), X and B may be the same or different in each constituent unit. That is, in the constituent units represented by general formula (9), X and B may each be independently included in one or more types. In general formula (9), X may be the same as X in the constituent units represented by formula (5) above, and B may be the same as B in the constituent units represented by general formula (5) above.

[0180] Other polyamide structural units, different from the structural unit represented by formula (5) above, which may be included in the polyamide structural unit, include, from the viewpoint of transparency, in the general formula (9) above, X is selected from the group consisting of structures represented by formulas (x1) to (x3) above, and B is a divalent group represented by formula (b2) above, Q b However, R is either -O-, -S-, -CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, or -SO2-, or in the divalent group represented by the general formula (3) above 5 and R 6 It is preferable that is a hydrogen atom or a methyl group, and in the divalent group represented by the above formula (b2), Q b However, in the case of a divalent group represented by the general formula (3) above, R 5 and R 6 It is more preferable that is a methyl group, and in the divalent group represented by the above formula (b2), Q b However, it is even more preferable that it be -C(CF3)2-.

[0181] (Polyamide-imide) The content of polyamide structural units containing the structural unit represented by formula (5) above is preferably 10 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, even more preferably 50 mol% or more, preferably 80 mol% or less, even more preferably 70 mol% or less, and even more preferably 60 mol% or less, relative to the total of polyimide structural units containing the structural unit represented by formula (4) above and polyamide structural units containing the structural unit represented by formula (5) above. If the content of polyamide structural units containing the structural unit represented by formula (5) above is within the above range, the composite elastic modulus and flexural resistance at room temperature of the resin layer tend to improve, and the solubility of polyamide-imide in solvents and flexural resistance under high temperature and high humidity conditions tend to improve.

[0182] The content of the dicarboxylic acid residue X having an aromatic ring in formula (5) above is preferably 10 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, even more preferably 50 mol% or more, preferably 80 mol% or less, even more preferably 70 mol% or less, and even more preferably 60 mol% or less, relative to the total of the tetracarboxylic acid residues and dicarboxylic acid residues in the polyamide-imide resin. If the content of the dicarboxylic acid residue X having an aromatic ring in formula (5) above is within the above range, the composite elastic modulus and flexural resistance at room temperature of the resin layer tend to improve, and the solubility of the polyamide-imide in solvents and flexural resistance under high temperature and high humidity conditions tend to improve.

[0183] Furthermore, polyamide-imide may have structures different from the above-mentioned polyimide constituent units and polyamide constituent units in part. Preferably, the total of polyimide constituent units containing the constituent unit represented by formula (4) and polyamide constituent units containing the constituent unit represented by formula (5) is 95% or more, more preferably 98% or more, and even more preferably 100% of the total constituent units of the polyamide-imide.

[0184] Examples of structures different from the above-mentioned polyimide and polyamide structural units include structural units in which the tetracarboxylic acid component is not completely imidized and has a polyamic acid structure in part, and polyamide-imide structural units containing tricarboxylic acid residues such as trimellitic anhydride.

[0185] The content percentage (mol%) of each constituent unit and each residue in polyamide-imide is: 1 The structure can be measured using 1H-NMR, and can also be determined from the raw material ratio during polyamide-imide production. Furthermore, the structure of polyamide-imide can be determined using NMR, various mass spectrometers, etc. In addition, the structure and content of each residue in polyamide-imide can be determined, for example, by decomposing polyamide-imide with an alkaline aqueous solution or supercritical methanol, and then using high-performance liquid chromatography, gas chromatography-mass spectrometry, NMR, elemental analysis, XPS / ESCA, and TOF-SIMS on the decomposition products.

[0186] The weight-average molecular weight of the polyamide-imide is preferably 50,000 or more, more preferably 100,000 or more, even more preferably 150,000 or more, preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 300,000 or less. If the weight-average molecular weight of the polyamide-imide resin is within the above range, it is less likely to cause appearance defects such as cracks and whitening after firing, making it easier to obtain a resin layer with good transparency, and it is also easier to form a resin layer by suppressing viscosity increases during synthesis, varnish preparation, and resin layer formation.

[0187] The method for measuring the weight-average molecular weight of polyamide-imide can be the same as the method for measuring the weight-average molecular weight of polyamide-imide described above.

[0188] (b) Additives The resin layer may contain additional additives as needed. Examples of additives include UV absorbers, light stabilizers, antioxidants, inorganic particles, silica fillers to facilitate winding, surfactants to improve film-forming and defoaming properties, and adhesion enhancers.

[0189] When the resin layer contains an ultraviolet absorber, the degradation of the resin layer due to ultraviolet light can be suppressed. In particular, when the resin layer contains polyimide, the color change of the polyimide-containing resin layer over time can be suppressed. Furthermore, in a display device equipped with a glass laminate, the degradation of components located on the display panel side of the glass laminate, such as polarizers, due to ultraviolet light can be suppressed.

[0190] Examples of UV absorbers included in the resin layer include triazine-based UV absorbers, benzophenone-based UV absorbers such as hydroxybenzophenone-based UV absorbers, and benzotriazole-based UV absorbers.

[0191] Specific examples of triazine-based UV absorbers, benzophenone-based UV absorbers such as hydroxybenzophenone-based UV absorbers, and benzotriazole-based UV absorbers can be found, for example, in Japanese Patent Publication No. 2019-132930.

[0192] Among the ultraviolet absorbers, triazine-based ultraviolet absorbers, hydroxybenzophenone-based ultraviolet absorbers, and benzotriazole-based ultraviolet absorbers are particularly preferred.

[0193] Furthermore, the UV absorber is preferably a polymer or oligomer. This is because it can suppress the bleed-out of the UV absorber when the glass laminate is repeatedly bent. Examples of such UV absorbers include polymers or oligomers having a triazine skeleton, a benzophenone skeleton, or a benzotriazole skeleton. Specifically, it is preferable that the UV absorber is obtained by thermal copolymerizing a (meth)acrylate having a benzotriazole skeleton or a benzophenone skeleton with methyl methacrylate (MMA) in any ratio.

[0194] The content of the UV absorber in the resin layer is not particularly limited, but is preferably 1% by mass or more and 6% by mass or less, and more preferably 2% by mass or more and 5% by mass or less. If the content of the UV absorber is too low, the effect of the UV absorber may not be sufficiently obtained. On the other hand, if the content of the UV absorber is too high, the resin layer may become significantly discolored or the strength of the resin layer may decrease.

[0195] (4) Method for forming a resin layer One method for forming the resin layer is to apply a resin composition onto a glass substrate. The application method is not particularly limited as long as it can be applied to the desired thickness, and common application methods include gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, and screen printing. In addition, as a method for forming the resin layer, a transfer method in which the resin layer is transferred to one side of the glass substrate, or a method in which a film-like resin layer is bonded to one side of the glass substrate via an adhesive layer can also be used.

[0196] The adhesive layer is transparent. Specifically, the total light transmittance of the adhesive layer is preferably 85% or higher, more preferably 88% or higher, and even more preferably 90% or higher.

[0197] Examples of adhesives used in the adhesive layer include OCA (Optical Clear Adhesive) and photosensitive adhesives.

[0198] The thickness of the adhesive layer is preferably, for example, 1 μm to 100 μm. If the adhesive layer is too thick, the flexibility may be impaired. On the other hand, if the adhesive layer is too thin, the adhesion may not be guaranteed and it may peel off.

[0199] The following explanation will use the case where the resin layer contains polyimide or polyamide-imide as an example.

[0200] (i) Method for forming a resin layer containing polyimide Methods for forming a resin layer containing polyimide include, for example, applying a polyimide varnish containing polyimide and an organic solvent to a glass substrate and drying it, and applying a polyimide precursor composition containing a polyimide precursor (polyamic acid) and an organic solvent to a glass substrate, and then imidizing the polyimide precursor by heat treatment or chemical treatment. In the former method, the heating conditions of the film formation process can be relaxed. On the other hand, in the latter method, the constraints on the solubility of polyimide are removed, thus increasing the options for the chemical structure of the polyimide.

[0201] In particular, the following manufacturing method is preferred because it is less prone to the occurrence of air bubble defects and makes it easier to obtain a resin layer with good thickness uniformity.

[0202] A method for forming a resin layer containing polyimide preferably comprises a preparation step of preparing a polyimide varnish containing polyimide and an organic solvent, wherein the polyimide content is 6% by mass or more and 15% by mass or less in the polyimide varnish, and the viscosity at 25°C is 1,000 cps or more and 50,000 cps or less; a coating step of applying the polyimide varnish onto a glass substrate; a first drying step of drying the coating film at a temperature of 140°C or lower; and a second drying step of heating the dried coating film at a temperature of 200°C or higher.

[0203] If polyimide dissolves well in an organic solvent, the heating conditions of the film formation process can be relaxed, so it is preferable to form a resin layer using a polyimide varnish obtained by dissolving polyimide in an organic solvent. Polyimide is easily soluble in organic solvents if it has a certain amount or more of constituent units containing tetracarboxylic acid residues of a specific structure, including a parabiphenylene group with a dihedral angle twisted via an ester bond in the main chain. If the polyimide has solvent solubility such that it dissolves in an organic solvent at 25°C at a concentration of 6% by mass or more, the above method for forming a resin layer can be suitably used.

[0204] According to the above method for forming the resin layer, the polyimide content in the varnish can be increased to a sufficient concentration, and the varnish can be adjusted to a desired viscosity range. As a result, a resin layer with good thickness uniformity and less prone to air bubble defects can be obtained.

[0205] The above organic solvent is not particularly limited as long as it can dissolve polyimide, and for example, aprotic polar solvents or water-soluble alcohol-based solvents can be used. In particular, it is preferable to use organic solvents containing nitrogen atoms such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone, or γ-butyrolactone. Furthermore, the above organic solvent can be used as one or a mixture of two or more solvents.

[0206] For a method of forming the resin layer containing the above-mentioned polyimide, refer to the methods described in, for example, Japanese Patent Publication No. 2019-1989 and Japanese Patent Publication No. 2019-182974.

[0207] (ii) Method for forming a resin layer containing polyamide-imide The method for forming a resin layer containing polyamide-imide is not particularly limited, and one example is to apply a polyamide-imide varnish containing polyamide-imide and an organic solvent to a glass substrate and then dry it.

[0208] The method for producing polyamideimide is not particularly limited, but for example, it can be produced by reacting one or more tetracarboxylic dianhydrides, including a tetracarboxylic dianhydride represented by formula (4-1) and optionally a tetracarboxylic dianhydride having an aromatic or aliphatic ring, with one or more diamines, including 2,2-bis(trifluoromethyl)-4,4-diaminobiphenyl and optionally a diamine having an aromatic or aliphatic ring, to obtain a polyimide precursor (polyamic acid); reacting the obtained polyimide precursor (polyamic acid) with a dicarboxylic acid component having an aromatic ring to obtain a polyamide-polyimide precursor (polyamic acid) copolymer; and imidizing the obtained polyamide-polyimide precursor (polyamic acid) copolymer.

[0209] The organic solvent contained in the polyamide-imide varnish can be the same as the organic solvent contained in the polyamide-imide varnish described above.

[0210] The method for applying the polyamide-imide varnish described above is not particularly limited as long as it can be applied to the desired thickness. Examples of common application methods include gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, and screen printing. Transfer methods can also be used to form the polyamide-imide varnish film.

[0211] After applying the polyamide-imide varnish, the solvent in the coating film is dried at a temperature of 150°C or lower, preferably between 30°C and 120°C, until the coating film becomes tack-free.

[0212] The drying time should be adjusted appropriately depending on the thickness of the coating film, the type of solvent, the drying temperature, etc. For example, it is preferable to have a drying time of 5 minutes or more and 60 minutes or less, preferably 10 minutes or more and 40 minutes or less. If the drying time is too long, the efficiency of resin layer formation may decrease. On the other hand, if the drying time is too short, the rapid drying of the solvent may affect the appearance of the resulting resin layer.

[0213] There are no particular restrictions on the method of drying the solvent, as long as it is possible to dry the solvent at the above temperature. For example, an oven, drying furnace, hot plate, infrared heating, etc., can be used.

[0214] The drying process may include a first drying step for drying the coating film and a second drying step for heating the dried coating film at a high temperature. The heating temperature in the second drying step is preferably, for example, 150°C or higher. From the viewpoint of flexibility, it is preferable to remove as much residual solvent as possible from the resin layer.

[0215] 3. Second resin layer The glass laminate in this disclosure may further have a second resin layer covering the side surface of the glass substrate. For example, in Figures 8 and 9, the second resin layer 13 is disposed on the side surface 1C of the glass substrate 1.

[0216] In the glass laminate described herein, the strength of the side surface of the glass substrate can be increased by covering it with a second resin layer. Furthermore, if the second resin layer is directly placed on the side surface of the glass substrate, the second resin layer can fill microcracks on the side surface of the glass substrate, thereby increasing its strength. As a result, cracking from the side surface of the glass substrate can be suppressed when the glass laminate is bent, further improving its flexibility. Moreover, impact resistance at the edges of the glass substrate can be improved.

[0217] The second resin layer preferably has shock-absorbing properties. Specifically, the composite elastic modulus of the second resin layer can be the same as that of the composite elastic modulus of the above resin layer.

[0218] Note that the measurement method of the complex elastic modulus of the second resin layer can be the same as that of the complex elastic modulus of the resin layer described above.

[0219] The thickness of the second resin layer is not particularly limited as long as it can provide flexibility and impact absorbency. For example, it is preferably 1 μm or more and 200 μm or less, and more preferably 10 μm or more and 100 μm or less. When the thickness of the second resin layer is within the above range, cracking of the glass substrate can be suppressed when the glass laminate is bent, and the flexural resistance can be improved. Furthermore, the impact resistance at the edge of the glass substrate can be improved.

[0220] Also, for example, as shown in FIG. 10, when the thickness of the resin layer 11 is T1 and the thickness of the second resin layer 13 is T2, the ratio of T1 to T2 (T1 / T2) is preferably 0.01 or more and 5.0 or less, more preferably 0.1 or more and 4.0 or less, and even more preferably 0.5 or more and 3.5 or less. When the ratio of the thicknesses is within the above range, cracking of the glass substrate can be suppressed when the glass laminate is bent, and the flexural resistance can be improved. Furthermore, the impact resistance at the edge of the glass substrate can be improved.

[0221] Here, the thickness of the second resin layer can be the average value of the thicknesses of any 10 locations obtained by measuring from the cross-section in the thickness direction of the glass laminate observed by a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM).

[0222] The degree of covering the side surface of the glass substrate by the second resin layer is not particularly limited as long as the strength of the side surface of the glass substrate can be increased by covering the side surface of the glass substrate with the second resin layer. For example, the entire side surface of the glass substrate may be covered with the second resin layer, or a part of the side surface of the glass substrate may be covered with the second resin layer.

[0223] The arrangement of the second resin layer is not particularly limited as long as the second resin layer covers the sides of the glass substrate. For example, if the shape of the glass substrate is a rectangular parallelepiped and is a hexahedron, it is sufficient that at least one of the four sides of the glass substrate is covered by the second resin layer. That is, in this case, one of the four sides of the glass substrate may be covered by the second resin layer, two may be covered by the second resin layer, three may be covered by the second resin layer, or all four may be covered by the second resin layer. In particular, it is preferable that all four sides of the glass substrate are covered by the second resin layer. When the glass laminate is bent, cracking of the glass substrate can be suppressed and the bending resistance can be improved. Furthermore, the impact resistance at the edges of the glass substrate can be improved.

[0224] The second resin layer is not particularly limited as long as it covers the side surface of the glass substrate; for example, it may be integrated with other layers of the glass laminate, or it may be a separate layer from the other layers.

[0225] Furthermore, the statement that the second resin layer is integral with the other layers means that the second resin layer and the other layers are formed continuously as a single layer.

[0226] When the second resin layer is integrated with other layers, examples of other layers include functional layers, which will be described later. For example, as shown in Figure 11, if a functional layer such as a hard coat layer 14 is arranged on the side of the resin layer 11 (surface side resin layer) opposite to the glass substrate 1, the second resin layer 13 may be integrated with the functional layer such as the hard coat layer 14.

[0227] The material of the second resin layer may be the same as the material used for the resin layer described above. Alternatively, the material used for the functional layer described later may be used for the second resin layer. If the second resin layer is integrated with the functional layer, it contains the same material as the functional layer.

[0228] The method for forming the second resin layer is appropriately selected depending on the morphology of the second resin layer.

[0229] For example, if the second resin layer is not integrated with other layers, the method for forming the second resin layer is not particularly limited as long as it can cover the side surface of the glass substrate, and one example is applying the resin composition to the side surface of the glass substrate. The application method is not particularly limited as long as it can be applied to the side surface of the glass substrate to a desired thickness, and examples include spray coating, dip coating, and methods using a dispenser.

[0230] On the other hand, for example, if the second resin layer is integrated with the functional layer, the second resin layer is formed simultaneously with the formation of the functional layer. As a method for forming the functional layer and the second resin layer, for example, a method of applying a resin composition to one main surface and side surface of a glass substrate is used. Examples of application methods include spin coating, die coating, spray coating, and dip coating. In this case, as a method for forming the functional layer and the second resin layer, a transfer method in which the functional layer and the second resin layer are transferred to one main surface and side surface of the glass substrate, or a method of laminating a resin film to one main surface and side surface of the glass substrate via an adhesive layer can also be used. The specific method can be the same as the method for forming the functional layer described later.

[0231] 4. Functional Layer The glass laminate in this disclosure may further have a functional layer on the side of the surface resin layer opposite to the glass substrate.

[0232] Examples of functional layers include hard coat layers, protective layers, anti-reflective layers, and anti-glare layers.

[0233] Furthermore, the functional layer may be a single layer or may consist of multiple layers. Also, the functional layer may be a layer having a single function or may consist of multiple layers having different functions. For example, the glass laminate in this disclosure may have a hard coat layer and a protective layer as functional layers, in that order from the resin layer side.

[0234] (1) Hard coat layer The glass laminate in this disclosure may further have a hard coat layer 14 on the side of the resin layer 11 (surface resin layer) opposite to the glass substrate 1, as shown in Figure 12, for example. The hard coat layer is a component for increasing surface hardness. The presence of the hard coat layer improves scratch resistance.

[0235] (a) Characteristics of the hard coat layer Here, "hard coat layer" refers to a component for increasing surface hardness, and specifically, in a configuration in which the glass laminate in this disclosure has a hard coat layer, it refers to a component that exhibits a hardness of "H" or higher when subjected to the pencil hardness test specified in JIS K 5600-5-4 (1999).

[0236] In the case where the glass laminate in this disclosure has a hard coat layer on the side of the surface resin layer opposite to the glass substrate, the pencil hardness of the surface on the hard coat layer side of the glass laminate is preferably H or higher, more preferably 2H or higher, and even more preferably 3H or higher.

[0237] Here, pencil hardness is measured using the pencil hardness test specified in JIS K5600-5-4 (1999). Specifically, using a test pencil specified in JIS-S-6006, the pencil hardness test specified in JIS K5600-5-4 (1999) is performed on the hard coat layer side of the glass laminate, and the highest pencil hardness at which scratching does not occur is evaluated. Measurement conditions can be an angle of 45°, a load of 750g, a speed of 0.5mm / sec to 1mm / sec, and a temperature of 23±2℃. As a pencil hardness tester, for example, a pencil scratch coating hardness tester manufactured by Toyo Seiki Co., Ltd. can be used.

[0238] (b) composition of the hard coat layer The hard coat layer may be a single layer or may have a multilayer structure of two or more layers. When the hard coat layer has a multilayer structure, in order to improve the surface hardness and to achieve a good balance between the flexural resistance and the elastic modulus, the hard coat layer preferably has a layer for satisfying the above pencil hardness and a layer for satisfying the flexural resistance (a layer for satisfying the abrasion resistance) when the above U-shaped bending test is repeatedly performed.

[0239] (c) Material of the hard coat layer As the material of the hard coat layer, for example, an organic material, an inorganic material, an organic-inorganic composite material, etc. can be used.

[0240] Among them, the material of the hard coat layer is preferably an organic material. Specifically, the hard coat layer preferably contains a cured product of a resin composition containing a polymerizable compound. The cured product of the resin composition containing a polymerizable compound can be obtained by subjecting the polymerizable compound to a polymerization reaction by a known method using a polymerization initiator as necessary.

[0241] (i) Polymerizable compound The polymerizable compound has at least one polymerizable functional group in the molecule. As the polymerizable compound, for example, at least one of a radical polymerizable compound and a cationic polymerizable compound can be used.

[0242] The radical polymerizable compound is a compound having a radical polymerizable group. The radical polymerizable group possessed by the radical polymerizable compound is not particularly limited as long as it is a functional group capable of causing a radical polymerization reaction, and examples thereof include a group containing a carbon-carbon unsaturated double bond, and specifically, a vinyl group, a (meth)acryloyl group, etc. are included. When the radical polymerizable compound has two or more radical polymerizable groups, these radical polymerizable groups may be the same or different from each other.

[0243] The number of radical polymerizable groups in a single molecule of a radical polymerizable compound is preferably two or more, and more preferably three or more, from the viewpoint of improving the hardness of the hard coat layer.

[0244] As radical polymerizable compounds, compounds having (meth)acryloyl groups are preferred due to their high reactivity. For example, polyfunctional (meth)acrylate monomers and oligomers with molecular weights of several hundred to several thousand and containing several (meth)acryloyl groups in the molecule, such as urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, polyfluoroalkyl (meth)acrylate, and silicone (meth)acrylate, can be preferably used. Polyfunctional (meth)acrylate polymers having two or more (meth)acryloyl groups in the side chain of the acrylate polymer can also be preferably used. In particular, polyfunctional (meth)acrylate monomers having two or more (meth)acryloyl groups in one molecule can be preferably used. By including cured products of polyfunctional (meth)acrylate monomers in the hard coat layer, the hardness of the hard coat layer can be improved, and the adhesion can be further improved. Furthermore, polyfunctional (meth)acrylate oligomers or polymers having two or more (meth)acryloyl groups in one molecule can also be preferably used. By including a cured product of the polyfunctional (meth)acrylate oligomer or polymer in the hard coat layer, the hardness and flexibility of the hard coat layer can be improved, and the adhesion can be further improved.

[0245] In this specification, (meth)acryloyl refers to acryloyl and methacryloyl respectively, and (meth)acrylate refers to acrylate and methacrylate respectively.

[0246] Specific examples of polyfunctional (meth)acrylate monomers can be found in, for example, Japanese Patent Publication No. 2019-132930. In particular, those having 3 to 6 (meth)acryloyl groups per molecule are preferred due to their high reactivity, improved hardness of the hard coat layer, and adhesion. For example, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate (PETTA), dipentaerythritol pentaacrylate (DPPA), trimethylolpropane tri(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, etc. are preferred, and at least one selected from pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexaacrylate, as well as those modified with PO, EO, or caprolactone, is preferred.

[0247] The resin composition may contain monofunctional (meth)acrylate monomers as radical polymerizable compounds for purposes such as adjusting hardness and viscosity, and improving adhesion. Specific examples of monofunctional (meth)acrylate monomers can be found in, for example, Japanese Patent Application Publication No. 2019-132930.

[0248] A cationic polymerizable compound is a compound having a cationic polymerizable group. The cationic polymerizable group of a cationic polymerizable compound can be any functional group capable of undergoing a cationic polymerization reaction, and is not particularly limited, but examples include epoxy groups, oxetanyl groups, and vinyl ether groups. If a cationic polymerizable compound has two or more cationic polymerizable groups, these cationic polymerizable groups may be the same or different.

[0249] The number of cationic polymerizable groups in one molecule of a cationic polymerizable compound is preferably two or more, and more preferably three or more, from the viewpoint of improving the hardness of the hard coat layer.

[0250] Furthermore, among cationic polymerizable compounds, compounds having at least one of epoxy and oxetanyl groups as cationic polymerizable groups are preferred, and compounds having two or more of at least one of epoxy and oxetanyl groups in one molecule are more preferred. Cyclic ether groups such as epoxy and oxetanyl groups are preferred because they exhibit less shrinkage during polymerization. In addition, compounds having epoxy groups among cyclic ether groups are readily available in a variety of structures, do not adversely affect the durability of the resulting hard coat layer, and have the advantage of being easy to control in terms of compatibility with radical polymerizable compounds. Moreover, among cyclic ether groups, oxetanyl groups have a higher degree of polymerization and lower toxicity compared to epoxy groups. When the resulting hard coat layer is combined with a compound having epoxy groups, it accelerates the network formation rate obtained from cationic polymerizable compounds in the coating film, and has the advantage of forming an independent network without leaving unreacted monomers in the film even in regions where it is mixed with radical polymerizable compounds.

[0251] Examples of cationic polymerizable compounds having epoxy groups include alicyclic epoxy resins obtained by epoxidizing polyglycidyl ethers of polyhydric alcohols having alicyclic rings, or compounds containing cyclohexene rings or cyclopentene rings, with a suitable oxidizing agent such as hydrogen peroxide or peracid; aliphatic epoxy resins such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts, polyglycidyl esters of aliphatic long-chain polybasic acids, and homopolymers and copolymers of glycidyl (meth)acrylates; glycidyl ethers produced by the reaction of bisphenols such as bisphenol A, bisphenol F, and hydrogenated bisphenol A, or derivatives thereof such as alkylene oxide adducts and caprolactone adducts, with epichlorohydrin, and novolac epoxy resins, as well as glycidyl ether-type epoxy resins derived from bisphenols.

[0252] Specific examples of alicyclic epoxy resins, glycidyl ether type epoxy resins, and cationic polymerizable compounds having an oxetanyl group can be found, for example, in Japanese Patent Application Publication No. 2018-104682.

[0253] Furthermore, the cured product of the resin composition containing polymerizable compounds in the hard coat layer can be analyzed using a Fourier transform infrared spectrophotometer (FTIR), a gas-centrifugation chromatograph (GC-MS), and, for the decomposition products of the polymer, a combination of high-performance liquid chromatography, gas chromatograph-mass spectrometry, NMR, elemental analysis, XPS / ESCA, and TOF-SIMS.

[0254] (ii) Polymerization initiator The resin composition may contain a polymerization initiator as needed. As the polymerization initiator, radical polymerization initiators, cationic polymerization initiators, radical and cationic polymerization initiators, etc., can be appropriately selected and used. These polymerization initiators decompose upon at least one of light irradiation and heating, generating radicals or cations to promote radical polymerization and cationic polymerization. Note that in some cases, the polymerization initiator may be completely decomposed and not remain in the hard coat layer.

[0255] Specific examples of radical polymerization initiators and cationic polymerization initiators can be found in, for example, Japanese Patent Publication No. 2018-104682.

[0256] (iii) particles The hard coat layer preferably contains inorganic or organic particles, and more preferably inorganic fine particles. The inclusion of particles in the hard coat layer can improve its hardness.

[0257] Examples of inorganic particles include silica (SiO2), metal oxide particles such as aluminum oxide, zirconia, titania, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, and cerium oxide; metal fluoride particles such as magnesium fluoride and sodium fluoride; metal particles; metal sulfide particles; and metal nitride particles. Among these, metal oxide particles are preferred, at least one selected from silica particles and aluminum oxide particles is more preferred, and silica particles are even more preferred because they provide excellent hardness.

[0258] Furthermore, it is preferable that the inorganic particles are reactive inorganic particles having photoreactive reactive functional groups on at least a portion of the particle surface that can crosslink with other inorganic particles or with at least one polymerizable compound to form covalent bonds. By crosslinking reactive inorganic particles with other reactive inorganic particles or with at least one radical polymerizable compound and a cationic polymerizable compound, the hardness of the hard coat layer can be further improved.

[0259] Reactive inorganic particles have at least a portion of their surface coated with an organic component, and have reactive functional groups introduced by the organic component on their surface. For example, polymerizable unsaturated groups are preferably used as reactive functional groups, and more preferably, photocurable unsaturated groups. Examples of reactive functional groups include (meth)acryloyl groups, vinyl groups, allyl groups, and other ethylenically unsaturated bonds, as well as epoxy groups.

[0260] The reactive silica particles are not particularly limited and conventionally known particles can be used, for example, the reactive silica particles described in Japanese Patent Application Publication No. 2008-165040. Commercially available reactive silica particles include, for example, MIBK-SD, MIBK-SDMS, MIBK-SDL, MIBK-SDZL from Nissan Chemical Industries, Ltd., and V8802, V8803 from JGC Catalysts & Chemicals Co., Ltd.

[0261] Furthermore, the silica particles may be spherical silica particles, but irregularly shaped silica particles are preferred. Spherical silica particles and irregularly shaped silica particles may be mixed. In this specification, irregularly shaped silica particles refer to silica particles with a potato-like, randomly uneven surface. Since irregularly shaped silica particles have a larger surface area compared to spherical silica particles, including such irregularly shaped silica particles increases the contact area with the resin components, etc., thereby improving the hardness of the hard coat layer.

[0262] Furthermore, whether or not the particles are irregularly shaped silica particles can be confirmed by cross-sectional observation of the hard coat layer using an electron microscope.

[0263] The average particle size of inorganic particles is preferably 5 nm or larger, and more preferably 10 nm or larger, from the viewpoint of improving hardness. If the average particle size of inorganic particles is too small, it becomes difficult to manufacture the particles, and there is a risk that the particles will aggregate easily. Furthermore, from the viewpoint of transparency, the average particle size of inorganic particles is preferably 200 nm or smaller, more preferably 100 nm or smaller, and even more preferably 50 nm or smaller. If the average particle size of inorganic particles is too large, there is a risk that large irregularities will be formed in the hard coat layer, and there is a risk of increased haze.

[0264] Here, the average particle size of inorganic particles can be measured by cross-sectional observation of the hard coat layer using an electron microscope, and the average particle size is defined as the average of the particle sizes of 10 arbitrarily selected particles. The average particle size of irregularly shaped silica particles is the average value of the maximum (major axis) and minimum (minor axis) distances between two points on the outer circumference of the irregularly shaped silica particles observed by cross-sectional microscopy of the hard coat layer.

[0265] The hardness of the hard coat layer can be controlled by adjusting the size and content of the inorganic particles. For example, the silica particle content is preferably 25 parts by mass or more and 60 parts by mass or less per 100 parts by mass of the polymerizable compound.

[0266] (iv) UV absorbers The hard coat layer may contain an ultraviolet absorber. This can suppress the degradation of the resin layer due to ultraviolet light. In particular, if the resin layer contains polyimide, it can suppress the color change of the polyimide-containing resin layer over time. Furthermore, in a display device equipped with a glass laminate, it can suppress the degradation of components located on the display panel side of the glass laminate, such as polarizers, due to ultraviolet light.

[0267] The UV absorber contained in the hard coat layer preferably has an absorption wavelength peak of 300 nm to 390 nm in absorbance measurements, more preferably 320 nm to 370 nm, and even more preferably 330 nm to 370 nm. This is because such a UV absorber can efficiently absorb UV light in the UVA region, and at the same time, by shifting its peak wavelength from the absorption wavelength of 250 nm of the initiator for curing the hard coat layer, it is possible to form a hard coat layer with UV absorption ability without inhibiting the curing of the hard coat layer.

[0268] Among UV absorbers, those with an absorption wavelength peak of 380 nm or less are preferable because they can suppress discoloration caused by the UV absorber. The absorbance of the ultraviolet absorber can be measured using, for example, a UV-Vis-Near-Infrared spectrophotometer (e.g., JASCO Corporation V-7100).

[0269] The ultraviolet absorber can be the same as the ultraviolet absorber used in the resin layer described above. In particular, from the viewpoint of suppressing degradation of the resin layer due to ultraviolet light, one or more ultraviolet absorbers selected from the group consisting of hydroxybenzophenone-based ultraviolet absorbers and benzotriazole-based ultraviolet absorbers are preferred, and one or more ultraviolet absorbers selected from the group consisting of hydroxybenzophenone-based ultraviolet absorbers are more preferred.

[0270] Specific examples of hydroxybenzophenone-based ultraviolet absorbers can be found, for example, in Japanese Patent Publication No. 2019-132930. Among the hydroxybenzophenone-based UV absorbers, 2-hydroxybenzophenone-based UV absorbers are preferred, and it is more preferable that one or more are selected from the group consisting of benzophenone-based UV absorbers having the following general formula (A). This can suppress the degradation of the resin layer due to ultraviolet light and improve its durability.

[0271] [ka]

[0272] (In general formula (A), X 1 and X 2 Each of these independently consists of a hydroxyl group and an -OR group. a , or represents a hydrocarbon group with 1 to 15 carbon atoms, R a (This represents a hydrocarbon group with 1 to 15 carbon atoms.)

[0273] In general formula (A), X 1 , X 2 and R a Examples of hydrocarbon groups having 1 to 15 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, dodecyl, allyl, and benzyl groups. Aliphatic hydrocarbon groups having 3 or more carbon atoms may be linear or branched. Hydrocarbon groups preferably have 1 to 12 carbon atoms, and more preferably 1 to 8. From the viewpoint of improving transparency, hydrocarbon groups are preferably aliphatic hydrocarbon groups, and among them, methyl and allyl groups are preferred. Because it is easier to improve durability, X 1 and X 2 Each of these independently represents a hydroxyl group or -OR a It is preferable that this be the case.

[0274] As one or more selected from the group consisting of benzophenone-based ultraviolet absorbers having the general formula (A), among others, it is preferably one or more selected from the group consisting of 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, and 2,2'-dihydroxy-4,4'-diallyloxybenzophenone, and more preferably one or more selected from the group consisting of 2,2',4,4'-tetrahydroxybenzophenone and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone. Specific examples of the benzotriazole-based ultraviolet absorber can include, for example, those described in JP-A-2019-132930.

[0275] As the benzotriazole-based ultraviolet absorber, among others, 2-(2-hydroxyphenyl)benzotriazoles are preferable, and more preferably one or more selected from the group consisting of benzotriazole-based ultraviolet absorbers having the following general formula (B). It can suppress the deterioration of the above resin layer by ultraviolet rays and improve the durability.

[0276] [Chemical formula]

[0277] (In the general formula (B), Y 1 , Y 2 , and Y 3 each independently represent a hydrogen atom, a hydroxyl group, -OR b , or a hydrocarbon group having 1 to 15 carbon atoms, R b represents a hydrocarbon group having 1 to 15 carbon atoms, and at least one of Y 1 , Y 2 , and Y 3 represents a hydroxyl group, -OR b , or a hydrocarbon group having 1 to 15 carbon atoms. Y 4 represents a hydrogen atom or a halogen atom.)

[0278] In the general formula (B), Y 1 , Y2 , and Y 3 , and R b Examples of hydrocarbon groups having 1 to 15 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and dodecyl groups. Aliphatic hydrocarbon groups having 3 or more carbon atoms may be linear or branched. Hydrocarbon groups preferably have 1 to 12 carbon atoms, and more preferably 1 to 8. From the viewpoint of improving transparency, hydrocarbon groups are preferably aliphatic hydrocarbon groups, preferably linear or branched alkyl groups, and among these, methyl, t-butyl, t-pentyl, n-octyl, or t-octyl groups are preferred.

[0279] In general formula (B), Y 4 Examples of halogen atoms in this compound include chlorine atoms, fluorine atoms, and bromine atoms, with chlorine atoms being preferred.

[0280] In general formula (B), among others, Y 1 , and Y 3 This is a hydrogen atom, Y 2 is a hydroxyl group, or -OR b It is preferable that the material represents 2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole and 2-(2,4-dihydroxyphenyl)-2H-benzotriazole, and more preferably one or more selected from the group. This can suppress degradation of the resin layer due to ultraviolet light and improve its durability.

[0281] The amount of UV absorber in the hard coat layer is preferably 10% by mass or less, and more preferably 7% by mass or less, from the viewpoint of suppressing haze caused by the mixing of UV absorbers. Furthermore, from the viewpoint of suppressing degradation of the resin layer due to ultraviolet rays and improving durability, the amount of UV absorber in the hard coat layer is preferably 1% by mass or more and 6% by mass or less, and more preferably 2% by mass or more and 5% by mass or less.

[0282] (v) Antifouling agents The hard coat layer may contain an antifouling agent. This can impart antifouling properties to the glass laminate.

[0283] The antifouling agent is not particularly limited and examples include silicone-based antifouling agents, fluorine-based antifouling agents, and silicone-based and fluorine-based antifouling agents. The antifouling agent may also be an acrylic-based antifouling agent. The antifouling agent may be used individually or in combination of two or more types.

[0284] Hard coat layers containing silicone-based or fluorine-based antifouling agents are less prone to fingerprints (less noticeable) and have good wipeability. Furthermore, the inclusion of silicone-based or fluorine-based antifouling agents can lower the surface tension of the curable resin composition for the hard coat layer during application, resulting in good leveling properties and a superior appearance for the resulting hard coat layer.

[0285] Furthermore, the hard coat layer containing a silicone-based antifouling agent has good slipperiness and good scratch resistance. In a display device equipped with a glass laminate having such a hard coat layer containing a silicone-based antifouling agent, the slipperiness when touched with a finger or pen is improved, resulting in a better tactile feel.

[0286] It is preferable that the antifouling agent has reactive functional groups to enhance the durability of its antifouling performance. If the antifouling agent does not have reactive functional groups, regardless of whether the glass laminate is in the form of a roll or a sheet, when the glass laminates are stacked, the antifouling agent may transfer to the side of the glass laminate opposite to the side with the hard coat layer. This may cause other layers to peel off when other layers are attached or coated to the side of the glass laminate opposite to the side with the hard coat layer, and furthermore, other layers may become more prone to peeling when repeatedly bent. In contrast, if the antifouling agent has reactive functional groups, the durability of its antifouling performance is improved.

[0287] The number of reactive functional groups in the antifouling agent may be one or more, preferably two or more. By using an antifouling agent having two or more reactive functional groups, excellent scratch resistance can be imparted to the hard coat layer.

[0288] Furthermore, the antifouling agent preferably has a weight-average molecular weight of 5000 or less. The weight-average molecular weight of the antifouling agent can be measured by gel permeation chromatography (GPC).

[0289] The antifouling agent may be uniformly dispersed in the hard coat layer, but from the viewpoint of obtaining sufficient antifouling properties with a small amount of additive and suppressing a decrease in the strength of the hard coat layer, it is preferable that it be unevenly distributed on the surface side of the hard coat layer.

[0290] Methods for distributing the antifouling agent unevenly on the surface side of the hard coat layer include, for example, a method in which, when forming the hard coat layer, the coating film of the curable resin composition for the hard coat layer is dried, and before curing, the coating film is heated to lower the viscosity of the resin components contained in the coating film, thereby increasing its fluidity and distributing the antifouling agent unevenly on the surface side of the hard coat layer; or a method in which an antifouling agent with low surface tension is used, the antifouling agent is allowed to float on the surface of the coating film without applying heat during drying, and then the coating film is cured, thereby distributing the antifouling agent unevenly on the surface side of the hard coat layer.

[0291] The amount of the antifouling agent is preferably, for example, 0.01 parts by mass or more and 3.0 parts by mass or less per 100 parts by mass of the resin component. If the amount of antifouling agent is too low, sufficient antifouling properties may not be imparted to the hard coat layer, and if the amount of antifouling agent is too high, the hardness of the hard coat layer may decrease.

[0292] (vi) Other coatings The hard coat layer may further contain additives as needed. These additives are selected appropriately according to the function to be imparted to the hard coat layer and are not particularly limited, but examples include inorganic or organic particles for adjusting the refractive index, infrared absorbers, anti-glare agents, anti-fouling agents, antistatic agents, colorants such as blue or purple pigments, leveling agents, surfactants, lubricants, various sensitizers, flame retardants, adhesion promoters, polymerization inhibitors, antioxidants, light stabilizers, and surface modifiers.

[0293] (d) thickness of the hard coat layer The thickness of the hard coat layer can be appropriately selected depending on the material of the hard coat layer, the function of the hard coat layer, and the application of the glass laminate. For example, if the material of the hard coat layer is an organic material, the thickness of the hard coat layer is preferably 2 μm to 50 μm, more preferably 3 μm to 30 μm, even more preferably 5 μm to 20 μm, and particularly preferably 6 μm to 10 μm. Also, if the material of the hard coat layer is an inorganic material, the thickness of the hard coat layer can be about several tens of nanometers. If the thickness of the hard coat layer is within the above range, sufficient hardness as a hard coat layer can be obtained, and a glass laminate with good flexibility can be obtained.

[0294] (e) Method for forming a hard coat layer The method for forming the hard coat layer is appropriately determined depending on the material of the hard coat layer, and examples include applying a curable resin composition for hard coat layers containing the polymerizable compound onto the resin layer and curing it, as well as vapor deposition and sputtering methods.

[0295] The hard coat layer curable resin composition contains a polymerizable compound and may further contain polymerization initiators, particles, UV absorbers, solvents, additives, etc., as needed.

[0296] There are no particular limitations on the method for applying the curable resin composition for the hard coat layer onto the resin layer, as long as it can be applied to the desired thickness. Examples of common application methods include gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, and screen printing. Transfer methods can also be used to form the coating film of the resin composition for the hard coat layer.

[0297] The coating film of the curable resin composition for the hard coat layer is dried to remove the solvent as needed. Drying methods include, for example, vacuum drying, heat drying, or a combination of these methods. For example, drying can be achieved by heating at a temperature of 30°C to 120°C for 10 to 180 seconds.

[0298] The method for curing the coating film of the hard coat layer curable resin composition can be appropriately selected depending on the polymerizable group of the polymerizable compound, and for example, at least one of light irradiation and heating can be used.

[0299] Light irradiation primarily uses ultraviolet light, visible light, electron beams, and ionizing radiation. For ultraviolet curing, for example, ultraviolet light emitted from ultra-high pressure mercury lamps, high-pressure mercury lamps, low-pressure mercury lamps, carbon arcs, xenon arcs, and metal halide lamps can be used. The irradiation dose from the energy source is, for example, 50 mJ / cm² as the integrated exposure dose at an ultraviolet wavelength of 365 nm. 2 More than 5000mJ / cm 2 It can be set to the following extent.

[0300] If heating is required, the reaction can be carried out at a temperature of, for example, 40°C to 120°C. Alternatively, the reaction can be carried out by leaving it at room temperature (25°C) for 24 hours or more.

[0301] Furthermore, as a method for forming the hard coat layer, a hard coat film in which the hard coat layer is arranged on one side of the base layer can be used, and the hard coat film can be bonded to the resin layer via an adhesive layer. In this case, the adhesive layer and the hard coat film having the base layer and hard coat layer can be arranged in this order on the side of the resin layer opposite to the glass base material.

[0302] The adhesive layer is transparent. Specifically, the total light transmittance of the adhesive layer is preferably 85% or higher, more preferably 88% or higher, and even more preferably 90% or higher.

[0303] Examples of adhesives used in the adhesive layer include OCA (Optical Clear Adhesive) and photosensitive adhesives.

[0304] The thickness of the adhesive layer is preferably, for example, 1 μm to 100 μm. If the adhesive layer is too thick, the flexibility may be impaired. On the other hand, if the adhesive layer is too thin, the adhesion may not be guaranteed and it may peel off.

[0305] (2) Protective layer The glass laminate in this disclosure may further have a protective layer on the side of the surface resin layer opposite to the glass substrate.

[0306] The protective layer is transparent. Specifically, the total light transmittance of the protective layer is preferably 85% or higher, more preferably 88% or higher, and even more preferably 90% or higher.

[0307] The protective layer is not particularly limited as long as it is transparent, and may include, for example, a resin. The resin used for the protective layer is not particularly limited as long as it can produce a transparent protective layer, and any general-purpose resin can be used.

[0308] Methods for placing a protective layer on a resin layer include, for example, using a protective film as the protective layer and bonding the protective film to the resin layer via an adhesive layer, or forming a protective layer on the resin layer.

[0309] The adhesive layer can be the same as the adhesive layer described in the section on the hard coat layer above.

[0310] 5. Other components The glass laminate in this disclosure may have other layers in addition to the above-mentioned layers, as needed. Examples of other layers include a primer layer, a decorative layer, and so on.

[0311] (1) Primer layer The glass laminate in this disclosure may have a primer layer between the glass substrate and the resin layer. The primer layer can improve the adhesion between the glass substrate and the resin layer.

[0312] The material of the primer layer is not particularly limited as long as it can improve the adhesion between the glass substrate and the resin layer, and resins can be used as examples. Examples of resins include (meth)acrylic resin, urethane resin, (meth)acrylic urethane copolymer, vinyl chloride-vinyl acetate copolymer, polyester, butyral resin, chlorinated polypropylene, chlorinated polyethylene, epoxy resin, and silicone resin. These resins may be used individually or in combination of two or more.

[0313] The thickness of the primer layer can be any thickness that is sufficient to improve the adhesion between the glass substrate and the resin layer. For example, it can be 0.1 μm or more and 10 μm or less, and preferably 0.2 μm or more and 5 μm or less.

[0314] One method for forming the primer layer is to apply a primer layer composition onto a glass substrate. Common application methods include gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, and screen printing. Transfer methods can also be used to form the primer layer.

[0315] (2) Decorative layer The glass laminate in this disclosure may have a decorative layer between the glass substrate and the surface resin layer, or on the side of the glass substrate opposite to the surface resin layer.

[0316] The decorative layer includes a coloring agent and a binder resin. The binder resin included in the decorative layer is not particularly limited, and any resin commonly used in decorative layers can be used. Furthermore, the coloring agent included in the decorative layer is not particularly limited, and any known coloring agent commonly used in decorative layers can be used. The decorative layer is typically placed on a portion of the glass substrate. The decorative layer may also have a patterned shape. The thickness of the decorative layer is not particularly limited, but can be, for example, 5 μm or more and 40 μm or less.

[0317] 6. Characteristics of glass laminates The glass laminate in this disclosure preferably has a total light transmittance of, for example, 80% or more, more preferably 85% or more, and even more preferably 88% or more. Such a high total light transmittance allows for a glass laminate with good transparency.

[0318] Here, the total light transmittance of the glass laminate can be measured in accordance with JIS K7361-1, for example, using a haze meter HM150 manufactured by Murakami Color Technology Laboratory.

[0319] The haze of the glass laminate in this disclosure is preferably 2.0% or less, more preferably 1.5% or less, and even more preferably 1.0% or less. Such low haze allows for a glass laminate with good transparency.

[0320] Here, the haze of the glass laminate can be measured in accordance with JIS K-7136, for example, using a haze meter HM150 manufactured by Murakami Color Technology Laboratory.

[0321] The glass laminate in this disclosure preferably has flexibility. Specifically, when the glass laminate is subjected to the U-shaped bending test described above, the distance between the opposing short sides of the glass laminate at which cracks or fractures occur is preferably 10 mm or less, and more preferably 5 mm or less.

[0322] In the U-shaped bending test, when the resin layer is arranged on only one of the first main surface side or the second main surface side of the glass substrate, the glass laminate may be folded so that the glass substrate is on the outside, or so that the glass substrate is on the inside. In either case, it is preferable that the above-mentioned bending resistance is achieved.

[0323] Furthermore, when performing the above-described dynamic bending test on a glass laminate, it is preferable that no cracks or fractures occur in the glass laminate when the bending of the glass laminate is repeated 200,000 times such that the distance between the opposing short sides of the glass laminate is 12 mm.

[0324] 7. Applications of glass laminates The glass laminates in this disclosure can be used in display devices as components positioned on the observer side of the display panel. For example, the glass laminates in this disclosure can be used in display devices for electronic devices such as smartphones, tablet devices, wearable devices, personal computers, televisions, digital signage, public information displays (PIDs), and in-vehicle displays. In particular, the glass laminates in this disclosure can be preferably used in flexible displays such as foldable displays, rollable displays, and bendable displays, and are especially preferably used in foldable displays.

[0325] In the glass laminate of this disclosure, when placed on the surface of a display device, if the resin layer is placed on only one of the first main surface side and the second main surface side of the glass substrate, the glass substrate side may be positioned so that the glass substrate side faces the display panel and the resin layer side faces outward, or the resin layer side may be positioned so that the resin layer side faces the display panel and the glass substrate side faces outward.

[0326] The method for arranging the glass laminate on the surface of a display device in this disclosure is not particularly limited and includes, for example, a method using an adhesive layer. As the adhesive layer, a known adhesive layer used for bonding glass laminates can be used.

[0327] C.Display device The display device in this disclosure comprises a display panel and the aforementioned glass substrate or glass laminate, which is positioned on the observer side of the display panel.

[0328] Figure 13 is a schematic cross-sectional view showing an example of a display device in this disclosure, which includes the glass laminate described above. As shown in Figure 13, the display device 20 comprises a display panel 21 and a glass laminate 10 positioned on the observer side of the display panel 21. In the display device 20, the glass laminate 10 is used as a component positioned on the surface of the display device 20, and an adhesive layer 22 is positioned between the glass laminate 10 and the display panel 21.

[0329] The glass substrate and glass laminate in this disclosure may be the same as those described above.

[0330] Examples of display panels in this disclosure include display panels used in display devices such as liquid crystal displays, organic EL displays, and LED displays.

[0331] The display device in this disclosure may have a touch panel member between the display panel and the glass substrate or glass laminate.

[0332] The display device in this disclosure is preferably a flexible display. In particular, the display device in this disclosure is preferably foldable. That is, the display device in this disclosure is more preferably a foldable display. Since the display device in this disclosure has the above-mentioned glass substrate or glass laminate, it has excellent impact resistance and bending resistance, and is suitable as a flexible display, and even more so as a foldable display.

[0333] D.Electronic equipment The electronic device in this disclosure includes the display device described above.

[0334] The electronic devices in this disclosure are not particularly limited as long as they are equipped with the above-mentioned display devices, and examples include smartphones, tablet devices, wearable devices, personal computers, televisions, digital signage, public information displays (PIDs), and in-vehicle displays.

[0335] E. Method for manufacturing glass laminates The method for manufacturing a glass laminate in this disclosure comprises a preparation step of preparing a glass substrate which is chemically strengthened glass and has a thickness of a predetermined value or less; a resin layer formation step of forming a resin layer on at least one of the first main surface side and the second main surface side of the glass substrate; and a cutting step of cutting the laminate having the glass substrate and the resin layer after the resin layer formation step.

[0336] Figures 14(a) to 14(c) are process diagrams showing an example of a method for manufacturing a glass laminate according to this disclosure. First, as shown in Figure 14(a), a preparation step is performed to prepare a glass substrate 1 which is chemically strengthened glass and has a thickness of a predetermined value or less. Next, as shown in Figure 14(b), a resin layer forming step is performed to form a resin layer 11 on the first main surface 1A side of the glass substrate 1. Subsequently, as shown in Figure 14(c), a cutting step is performed to cut the laminate 10A having the glass substrate 1 and the resin layer 11.

[0337] In the manufacturing method of the glass laminate shown in Figures 14(a) to (c), the resin layer 11 is formed only on the first main surface 1A side of the glass substrate 1 during the resin layer formation process. However, as shown in Figures 15(a) to (c), the resin layer 11 may be formed on the first main surface 1A side of the glass substrate 1 and the resin layer 12 may be formed on the second main surface 1B side of the glass substrate 1 during the resin layer formation process.

[0338] Conventionally, in the manufacturing method of glass laminates, because cutting chemically strengthened glass is difficult, the glass substrate was first cut to the desired size, then the cut glass substrate was subjected to chemical strengthening treatment, and then a resin layer was formed on the glass substrate. As a result, the manufacturing process could not be carried out without cutting large glass substrates, resulting in low productivity.

[0339] In contrast, in the method for manufacturing a glass laminate according to this disclosure, a resin layer is formed on a glass substrate which is chemically strengthened glass, and then the laminate of the glass substrate and the resin layer is cut. Therefore, the manufacturing process can be carried out without cutting large pieces of chemically strengthened glass, thereby increasing productivity.

[0340] The following describes each step in the method for manufacturing the glass substrate as described in this disclosure. 1. Preparation process In the preparation step described herein, a glass substrate is prepared that is chemically strengthened glass and has a thickness of less than or equal to a predetermined value. The thickness of the glass substrate is described in section "A. Glass Substrate" above, so the explanation is omitted here.

[0341] The chemically strengthened glass constituting the glass substrate is not particularly limited; for example, it may be six-sided tempered glass or two-sided tempered glass, but six-sided tempered glass is usually used. Regarding other aspects of the glass constituting the glass substrate, the same as described in section "A. Glass Substrate" above can be used, so a detailed explanation is omitted here.

[0342] The glass substrate may be in the form of a single leaf or a roll. The size of the glass substrate is not particularly limited, but a large glass substrate is preferred. Examples of large glass substrates include multi-faceted glass substrates for creating multi-faceted components for display devices, and roll-shaped glass substrates.

[0343] 2.Resin layer formation process In the resin layer formation process described herein, a resin layer is formed on at least one of the first main surface side and the second main surface side of the glass substrate. The resin layer and its formation method are described in section "B. Glass Laminate 2. Resin Layer" above, so the explanation is omitted here.

[0344] 3.Cutting process In the cutting process described herein, after the resin layer formation process, the laminate having the glass substrate and the resin layer is cut.

[0345] When cutting the glass substrate and resin layer, for example, the glass substrate and resin layer may be cut in separate processes, or they may be cut in a single cutting process. Furthermore, when the glass substrate and resin layer are cut in separate processes, the cutting methods for the glass substrate and resin layer may be the same or different. Also, when the resin layer is formed on only one of the first main surface side and the second main surface side of the glass substrate, the order of cutting the glass substrate and resin layer is usually to cut the resin layer first, and then the glass substrate.

[0346] When cutting the glass substrate and resin layer in separate processes, methods for cutting the glass substrate include, for example, scribing, chemical etching, and laser cutting. Alternatively, a mechanical scribing method using the "SOLID-D" cutter manufactured by Mitsuboshi Diamond Industrial Co., Ltd. can be used.

[0347] Furthermore, when cutting the glass substrate and the resin layer in separate processes, methods for cutting the resin layer include, for example, cutting by scribing, cutting by an ultrasonic cutter, laser cutting using a UV laser or CO2 laser, and cutting using a cutting blade. In addition, a mechanical scribing method using the "SOLID-D" cutter manufactured by Mitsuboshi Diamond Industrial Co., Ltd. can be used.

[0348] Furthermore, when cutting the glass substrate and resin layer in a single cutting process, one possible method for cutting the glass substrate and resin layer is, for example, cutting by scribing.

[0349] 4. Processing process The method for manufacturing a glass laminate in this disclosure preferably includes a processing step of processing the cut surface of the glass substrate so that the maximum height Sz of the cut surface of the glass substrate is less than or equal to a predetermined value. By keeping the maximum height Sz of the cut surface of the glass substrate less than or equal to a predetermined value, the bending resistance can be improved as described in section "A. Glass Substrate" above. Furthermore, the impact resistance at the edges of the glass laminate can be improved.

[0350] In the method for manufacturing a glass laminate according to this disclosure, the processing step may be performed during the cutting step, or after the cutting step. Specifically, when processing the cut surface of the glass substrate, the glass substrate may be cut so that the maximum height Sz of the cut surface of the glass substrate is less than or equal to a predetermined value, or the cut surface of the glass substrate may be processed while cutting the glass substrate so that the maximum height Sz of the cut surface of the glass substrate is less than or equal to a predetermined value, or the cut surface of the glass substrate may be processed after cutting the glass substrate so that the maximum height Sz of the cut surface of the glass substrate is less than or equal to a predetermined value.

[0351] More specifically, a method is used in which the glass substrate and resin layer are cut by scribing, the cut surface of the glass substrate is polished with abrasive paper, and then polished further with diamond abrasive grains. The particle size of the abrasive material on the abrasive paper is preferably 30 μm or less, and particularly preferably 15 μm. The abrasive material on the abrasive paper is not particularly limited. The particle size of the diamond abrasive grains is preferably 3 μm or less, and particularly preferably 1 μm.

[0352] 5. Second resin layer formation process The method for manufacturing a glass laminate in this disclosure may further include a second resin layer forming step in which the side surface of the glass substrate is covered with a second resin layer after the cutting step. By covering the sides of the glass substrate with a second resin layer, the flexibility can be improved as described in section "A. Glass Substrate" above. Furthermore, the impact resistance at the edges of the glass laminate can be improved. The second resin layer and its formation method are described in section "B. Glass Laminate 3. Second Resin Layer" above, so the explanation is omitted here.

[0353] 6.Functional layer formation process In the method for manufacturing a glass laminate according to this disclosure, a functional layer formation step may be performed after the resin layer formation step to form a functional layer on the side of the surface resin layer opposite to the glass substrate.

[0354] The functional layer formation process may be performed before or after the cutting process, but from the viewpoint of improving productivity, it is preferable to perform it before the cutting process. When the functional layer formation process is performed before the cutting process, the cutting process involves cutting the laminate having a glass substrate, a resin layer, and a functional layer. The functional layer and its formation method are described in section "B. Glass Laminate 4. Functional Layer" above, so the explanation is omitted here.

[0355] 7. Other processes In the method for manufacturing a glass laminate according to this disclosure, a primer layer formation step may be performed before the resin layer formation step, in which a primer layer is formed on the surface of the glass substrate on which the resin layer will be formed. In this case, the cutting step cuts the laminate having the glass substrate, primer layer and resin layer. The primer layer and the method for forming it are described in the section "B. Glass Laminate 5. Other Structures" above, so the explanation is omitted here.

[0356] Furthermore, in the method for manufacturing a glass laminate according to this disclosure, a decorative layer formation step may be performed before the resin layer formation step, in which a decorative layer is formed on one side of the glass substrate. In this case, the cutting step cuts the laminate having the glass substrate, the decorative layer, and the resin layer. The decorative layer and the method for forming it are described in the section "B. Glass Laminate 5. Other Structures" above, so a detailed explanation is omitted here.

[0357] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure. [Examples]

[0358] The present disclosure will be further explained below with reference to examples and comparative examples. [Comparative Example 1] The glass substrate was cut, chamfered, and chemically strengthened in that order. First, an untempered glass sheet with a thickness of 70 μm and dimensions of 200 mm x 200 mm was prepared and cut by scribing to a size of 20 mm x 100 mm. After that, the cut surface of the glass substrate was polished and chamfered. Next, the glass substrate was subjected to chemical strengthening treatment to obtain six-sided tempered glass.

[0359] [Comparative Example 2] The glass substrate was cut and then chemically strengthened in that order. A 6-sided tempered glass was obtained in the same manner as in Comparative Example 1, except that the cut surface of the glass substrate was not chamfered.

[0360] [Comparative Example 3] Chemical strengthening and cutting of the glass substrate were performed in sequence. First, a glass substrate measuring 200 mm x 200 mm and 70 μm thick was chemically strengthened to obtain six-sided tempered glass. Next, the glass substrate was cut from the center outwards to a size of 20 mm x 100 mm using a picosecond laser with a pulse energy of 80 μJ and an oscillation frequency of 150 kHz to obtain two-sided tempered glass.

[0361] [Comparative Example 4] Chemical strengthening and cutting of the glass substrate were performed in sequence. The glass substrate was cut in the same manner as in Comparative Example 3, except that the cutting conditions using a picosecond laser were set to a pulse energy of 9 μJ and an oscillation frequency of 300 kHz.

[0362] [Comparative Example 5] The glass substrate was subjected to slimming, cutting, chamfering, and chemical strengthening in that order. Six-sided tempered glass was obtained in the same manner as in Comparative Example 1, except that the 70 μm thick untempered glass was slimmed down to a thickness of 60 μm before cutting.

[0363] [Comparative Example 6] Chemical strengthening and cutting of the glass substrate were performed in sequence. The glass substrate was cut in the same manner as in Comparative Example 3, except that the method of cutting the glass substrate was to cut it by scribing with a pressing depth of 0.1 mm and a speed of 20 mm / sec.

[0364] [Comparative Example 7] The glass substrate was cut in the same manner as in Comparative Example 6, except that a glass substrate with a thickness of 14 μm was used.

[0365] [Comparative Example 8] The glass substrate was cut in the same manner as in Comparative Example 6, except that a glass substrate with a thickness of 110 μm was used.

[0366] [Example 1] Chemical strengthening and cutting (special polishing) of the glass substrate were performed in sequence. The glass substrate was cut with a scribe in the same manner as in Comparative Example 6. Then, the cut surface of the glass substrate was polished with abrasive paper containing 15 μm abrasive particles, followed by polishing with 1 μm diamond abrasive particles. In this specification, the process from scribing to polishing is referred to as special polishing.

[0367] [Example 2] Chemical strengthening and cutting (special polishing) of the glass substrate were performed in sequence. The cutting and polishing of the cut surface of the glass substrate were carried out in the same manner as in Example 1, except that a glass substrate made of 6-sided tempered glass that had not been chamfered was used.

[0368] [Example 3] A glass substrate was obtained in the same manner as in Example 2, except that the polishing time was 0.9 times that of Example 2.

[0369] [Example 4] A glass substrate was obtained in the same manner as in Example 2, except that the polishing time was 1.1 times that of Example 2.

[0370] [Example 5] Chemical strengthening and cutting (special polishing) of a glass substrate were performed in sequence. First, a glass measuring 200 mm x 200 mm with a thickness of 70 μm was slimmed down to 60 μm, chemically strengthened, and obtained 6-sided tempered glass. Then, cutting (special polishing) was performed in the same manner as in Example 1 to obtain 2-sided tempered glass.

[0371] [Example 6] Except for changing the chemical strengthening method to set the CS and CT values ​​to the values ​​shown in Table 1, the glass substrate was cut and the cut surface of the glass substrate was polished in the same manner as in Example 1.

[0372] [Example 7] Chemically strengthened glass substrates with a thickness of 70 μm, which were chemically strengthened to achieve the CS and CT values ​​shown in Table 1, were cut by scribing them with a cutter (SOLID-D, manufactured by Mitsuboshi Diamond Industrial Co., Ltd.) and then breaking them.

[0373] [Example 8] Chemically strengthened glass substrates with a thickness of 50 μm, which were chemically strengthened to achieve the CS and CT values ​​shown in Table 1, were cut by scribing them with a cutter (SOLID-D, manufactured by Mitsuboshi Diamond Industrial Co., Ltd.) and then breaking them.

[0374] [Example 9] Chemically strengthened glass substrates with a thickness of 30 μm, which were chemically strengthened to achieve the CS and CT values ​​shown in Table 1, were cut by scribing them with a cutter (SOLID-D, manufactured by Mitsuboshi Diamond Industrial Co., Ltd.) and then breaking them.

[0375] [Rating 1] (1) Surface compressive stress (CS) and internal tensile stress (CT) of chemically strengthened glass For the glass substrate, surface compressive stress and internal tensile stress were measured from the first or second principal surface using a Refractometer-type glass surface stress meter FSM-6000LE manufactured by Lukeo.

[0376] (2) Maximum height Sz The maximum height Sz of the side surface of the glass substrate was measured using the VertScan2.0 R5500GML-A150-AC non-contact surface and layer cross-sectional shape measurement system manufactured by Ryoka Systems Co., Ltd. Various parameters were determined based on ISO 25178, measurements were taken at 10 arbitrary locations, and the arithmetic mean was calculated. The measurement conditions were as follows. • Measurement area: 0.02mm x 0.02mm • Objective lens: 50x • Measurement mode: Wave • Wavelength filter: 530 white • Height analysis mode: PV mode

[0377] The measurement will be performed using the following method. As shown in Figure 18, first, the glass substrate 101 is fixed by sandwiching it between two jigs 100, 100 on the stage S. Next, the lens 102 equipped with a light source is positioned directly above the side surface of the glass substrate 101. The tilt of the stage S is adjusted so that the direction of light from the light source is perpendicular to the stage S. Finally, by adjusting the height of the stage S, the distance between the lens 102 and the side surface of the glass substrate 101 is adjusted to focus, and then the measurement is performed.

[0378] Furthermore, color images of the glass substrates of Comparative Examples 3 and 6 and Example 4, acquired using the VertScan2.0 R5500GML-A150-AC non-contact surface and layer cross-sectional shape measurement system manufactured by Ryoka Systems Co., Ltd., are shown in Figures 16(a) and 16(b) and Figure 17, respectively.

[0379] (3) U-shaped bending test The U-shaped bending test described above was performed on the glass substrate. The distance d between the two opposing short sides of the glass substrate was measured when cracking or fracture occurred. The results of the U-shaped bending test were evaluated according to the following criteria. A: The maximum gap d when cracks or fractures occur in the glass substrate is 5 mm or less. B: The maximum gap d when cracks or fractures occur in the glass substrate is greater than 5 mm and less than or equal to 10 mm. C: The maximum gap d when cracks or fractures occur in the glass substrate is greater than 10 mm.

[0380] (4) Dynamic flexion test The glass substrate was subjected to the dynamic bending test described above to evaluate its bending resistance. In this test, the distance d between the two opposing short sides of the glass substrate was set to 10 mm. The results of the dynamic bending test were evaluated according to the following criteria. A: The glass substrate will not break even after 200,000 cycles. B: The glass substrate will not break even after 20,000 cycles. C: Fracture occurred in the glass substrate after less than 20,000 cycles.

[0381] (5) Impact test (pen drop test) An impact test was performed on a glass substrate. First, a test laminate was prepared by laminating a 50 μm thick optical adhesive film (OCA) and a 100 μm thick PET film onto the glass substrate in that order. The test laminate was placed on a 30 mm thick metal plate so that the PET film side of the test laminate was in contact with the metal plate. Next, a pen was dropped onto the edge of the test laminate from a predetermined test height, with its tip facing downwards. Here, the edge of the test laminate refers to the area within 5 mm from the edge of the glass substrate.

[0382] A Zebra Blenn 0.5BAS88-BK pen (weight 12g, 0.5mm diameter tip) was used for the test. The maximum test height at which the glass substrate did not crack was measured at the edge of the glass substrate. A higher value indicates greater impact resistance.

[0383] The results of the impact tests were evaluated according to the following criteria. A: The maximum test height at which no cracks occurred in the glass substrate was 3 cm or more. B: The maximum test height at which no crack occurred in the glass substrate was less than 3 cm.

[0384] (6) Production efficiency (number of sheets processed) The production efficiency of the glass substrate manufacturing method was evaluated according to the following criteria. The number of samples processed per unit time in Comparative Example 1 was used as the baseline value. Here, the number of samples processed refers to the number of samples produced within a predetermined time (5 hours). When counting the number of samples processed, samples in which the glass broke are not included. Glass breakage is defined as a sample that was produced but separated into two or more pieces. A: The number of sheets processed per unit of time is more than three times the standard value. B: The number of sheets processed per unit of time is 1x or less of the standard value.

[0385] [Table 1]

[0386] Generally, when the glass substrate is tempered on two sides, there is no compressive stress layer on the sides of the glass substrate, resulting in reduced strength on the sides. However, as shown in Table 1, even in the case of tempered glass on two sides, it was confirmed that good bending resistance and impact resistance at the edges of the glass substrate were achieved when the maximum height Sz of the sides of the glass substrate was below a predetermined value (Examples 1-9). Furthermore, it was confirmed that even in the case of tempered glass on two sides, when the maximum height Sz of the sides of the glass substrate was below a predetermined value (Examples 1-9), bending resistance comparable to that of tempered glass on six sides (Comparative Examples 1-2) could be obtained.

[0387] [Comparative Example 9] (Formation of primer layer) The hexagonal tempered glass obtained in Comparative Example 1 was used. The following primer layer composition was coated onto the glass substrate and dried at 80°C for 3 minutes and at 150°C for 60 minutes to form a primer layer with a thickness of 1 μm.

[0388] <Composition for primer layer> • Bisphenol A type solid epoxy resin (jER1256B40, manufactured by Mitsubishi Chemical Corporation) 28 parts by mass • Bisphenol A novolac type solid epoxy resin (jER157S65B80, manufactured by Mitsubishi Chemical Corporation) 5 parts by mass • 2-Ethyl-4-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 1 part by mass • Solvent (MEK) 11 parts by mass

[0389] (Formation of resin layer) Referring to Synthesis Example 1 in International Publication No. 2014 / 046180, a tetracarboxylic dianhydride represented by the following chemical formula was synthesized.

[0390] [ka]

[0391] In a 5 L separable flask, a solution containing dehydrated N,N-dimethylacetamide (DMAc) (1833.2 g) and 2,2'-bis(trifluoromethyl)benzidine (TFMB) (138.48 g) was added. The solution temperature was controlled to 30°C. Then, tetracarboxylic dianhydride (TMPBPTME) (176.70 g), represented by the above chemical formula, was gradually added so that the temperature rise would be less than 2°C, and the mixture was stirred with a mechanical stirrer for 30 minutes. Pyromellitic dianhydride (PMDA) (64.20 g) was then gradually added in several batches so that the temperature rise would be less than 2°C, synthesizing a polyimide precursor solution (solid content 18% by mass) in which the polyimide precursor was dissolved. The molar ratio (TMPBPTME:PMDA) of the tetracarboxylic dianhydrides TMPBPTME and PMDA used in the polyimide precursor was 90:10. The weight-average molecular weight of the polyimide precursor was 75,000.

[0392] Under a nitrogen atmosphere, 2162g of the above polyimide precursor solution (at room temperature) was added to a 5L separable flask. Then, 432g of dehydrated N,N-dimethylacetamide was added and the mixture was stirred until homogeneous. Next, pyridine (6.622g) and acetic anhydride (213.67g), which serve as catalysts, were added and the mixture was stirred at room temperature for 24 hours to synthesize the polyimide solution.

[0393] N,N-dimethylacetamide (DMAc) (2000 g) was added to the obtained polyimide solution and stirred until homogeneous. Next, the polyimide solution was divided into three equal parts and transferred to 5 L beakers. Isopropyl alcohol (3500 g) was gradually added to each beaker to obtain a white slurry. The slurry was transferred to a Buchner funnel and filtered, then washed by rinsing with isopropyl alcohol (total 9000 g), and filtered again. This process was repeated three times, and the mixture was dried at 110°C using a vacuum dryer to obtain polyimide (polyimide powder). The weight-average molecular weight of the polyimide, as measured by GPC, was 100,000.

[0394] A polyimide varnish (resin composition) containing 12% polyimide by mass was prepared by adding N,N-dimethylacetamide (DMAc) to polyimide so that the solid content concentration of polyimide was 12% by mass. The viscosity of the polyimide varnish (resin composition) (solid content concentration 12% by mass) at 25°C was 15,000 cps.

[0395] The above-mentioned polyimide varnish (resin composition) was applied to the above-mentioned primer layer to a predetermined thickness, and dried at 80°C for 5 minutes, 150°C for 10 minutes, and 230°C for 30 minutes to form a resin layer with a thickness of 20 μm.

[0396] [Comparative Example 10] In Comparative Example 9, the primer layer and resin layer were formed on the glass substrate in the same manner as in Comparative Example 9, except that the hexagonal tempered glass obtained in Comparative Example 2 was used and the thickness of the resin layer was 5 μm.

[0397] [Example 10] First, a glass substrate measuring 200 mm x 200 mm and 70 μm thick was prepared. The cut surface of the glass substrate was polished and chamfered, and then the glass substrate was subjected to a chemical strengthening treatment to obtain a 6-sided tempered glass measuring 200 mm x 200 mm and 70 μm thick. Next, a primer layer and a resin layer were formed on the glass substrate in the same order as in Comparative Example 9, using the same primer layer composition, resin composition, and application conditions. Then, the resin layer and primer layer were cut with an ultrasonic cutter to a size of 100 mm x 20 mm, and the glass substrate was cut with a scribe at a pressure of 0.1 mm and a speed of 20 mm / sec. After that, the cut surface of the glass substrate was polished with abrasive paper containing abrasive material with a particle size of 15 μm, and then polished with diamond abrasive grains with a particle size of 1 μm.

[0398] [Example 11] In Example 10, a primer layer and a resin layer were formed on a glass substrate in the same manner as in Example 10, except that the resin layer was formed as described below. The resin layer, primer layer, and glass substrate were then cut, and the cut surface of the glass substrate was polished.

[0399] (Formation of resin layer) A resin composition containing a urethane-modified copolymer polyester resin (Byron UR-4800, manufactured by Toyobo Co., Ltd.) was deposited on a glass substrate to a predetermined thickness, forming a resin layer with a thickness of 20 μm. The drying conditions during resin layer formation were 100°C for 3 minutes.

[0400] [Example 12] First, a 200mm x 200mm, 70μm thick glass was slimmed down to 60μm and chemically strengthened to obtain a 6-sided tempered glass measuring 200mm x 200mm and 60μm thick. A glass laminate was obtained in the same manner as in Example 10, except that the obtained glass was used and the thickness of the resin layer was set to 25μm.

[0401] [Example 13] A glass laminate was obtained in the same manner as in Example 12, except that the resin layer was formed as described below.

[0402] (Formation of resin layer) A polyurethane resin film was deposited on a glass substrate to a predetermined thickness, forming a resin layer with a thickness of 15 μm. The drying conditions during resin layer formation were 100°C for 10 minutes.

[0403] [Example 14] In Example 10, a glass laminate was obtained in the same manner as in Example 10, except that the tempered glass obtained in Example 8 was used and the thickness of the resin layer was set to 20 μm.

[0404] [Example 15] In Example 10, a glass laminate was obtained in the same manner as in Example 10, except that the tempered glass obtained in Example 9 was used and the thickness of the resin layer was set to 25 μm.

[0405] [Example 16] After forming the primer layer shown in Comparative Example 9 on the reinforced glass substrate obtained in Example 8, a resin composition with the following composition was applied and the solvent was evaporated by drying at 70°C. Then, ultraviolet light was applied with an integrated light intensity of 500 mJ / cm². 2 By irradiating the material, a resin layer with a thickness of 30 μm was formed, and a glass laminate was obtained. (Resin composition) • Acrylate monomer: 100 parts by mass • Silica particles (average particle size 30-50 nm): 50 parts by mass ·Photopolymerization initiator: 4 parts by mass • Solvent (MEK): 100 parts by mass

[0406] [Rating 2] (1) Compound modulus The composite elastic modulus of the resin layer was measured using the method for measuring the composite elastic modulus of the resin layer described above.

[0407] (2) Maximum height Sz For the glass laminate, the maximum height Sz of the side surface of the glass substrate was measured in the same manner as in Example 1.

[0408] (3) U-shaped bending test The aforementioned U-shaped bending test was performed on the glass laminate. The distance d between two opposing short sides of the glass laminate was measured when no cracks or fractures occurred. The results of the U-shaped bending test were evaluated according to the following criteria. A: The minimum distance d in the glass laminate when no cracks or fractures occur is 5 mm or less. B: The minimum distance d in the glass laminate when no cracks or fractures occur is greater than 5 mm and less than or equal to 10 mm. C: The minimum distance d in the glass laminate that does not crack or break is greater than 10 mm.

[0409] (4) Dynamic flexion test The glass laminate was subjected to the dynamic bending test described above to evaluate its bending resistance. The distance d between the two opposing short sides of the glass laminate was set to 10 mm. The glass laminate was bent so that the resin layer was on the inside and the glass substrate was on the outside. The results of the dynamic bending test were evaluated according to the following criteria. A: The glass substrate must not break even after 200,000 cycles, and the resin layer must not crack. B: No fracture of the glass substrate or cracking of the resin layer even after 20,000 cycles. C: Fracture of the glass substrate or cracking of the resin layer occurs before 20,000 cycles.

[0410] (5) Impact test (pen drop test) An impact test was performed on the glass laminate. First, a test laminate was prepared by laminating a 50 μm thick optical adhesive film (OCA) and a 100 μm thick PET film in that order onto the glass substrate surface of the glass laminate. The test laminate was then placed on a 30 mm thick metal plate so that the PET film side of the test laminate was in contact with the metal plate.

[0411] Next, a pen was dropped onto the test laminate from a predetermined test height, tip-down, onto the edge of the test laminate. Here, the edge of the test laminate refers to the area within 5 mm from the edge of the glass substrate.

[0412] A Zebra Blenn 0.5BAS88-BK pen (weight 12g, pen tip 0.5mmφ) was used. The maximum test height at which no crack occurred in the glass substrate was measured at the edge of the glass laminate. A higher value indicates higher impact resistance. The impact test results were evaluated according to the following criteria. A: The maximum test height at which no cracks occurred in the glass substrate was 11 cm or more. B: The maximum test height at which no cracks occurred in the glass substrate was between 7 cm and 11 cm. C: The maximum test height at which no crack occurred in the glass substrate was less than 7 cm.

[0413] (6) Production efficiency (number of sheets processed) The production efficiency of the glass laminate manufacturing method was evaluated according to the following criteria. The number of sheets processed per unit time in Comparative Example 6 was used as the baseline value. Here, the number of sheets processed refers to the number of samples produced within a predetermined time (5 hours). When counting the number of sheets processed, samples in which the glass broke are not included. Glass breakage is defined as a sample that was produced but separated into two or more pieces. A: The number of sheets processed per unit of time is more than three times the standard value. B: The number of sheets processed per unit of time is 1x or less of the standard value.

[0414] [Table 2]

[0415] Table 2 shows that, in glass laminates, even when the glass substrate is tempered on two sides, good bending resistance and impact resistance at the edges of the glass laminate are achieved when the maximum height Sz of the side surface of the glass substrate is below a predetermined value. Furthermore, even when the glass substrate is tempered on two sides, it was confirmed that bending resistance comparable to that of six-sided tempered glass (Comparative Examples 7-8) can be obtained when the maximum height Sz of the side surface of the glass substrate is below a predetermined value (Examples 6-9).

[0416] [Reference example] The potassium concentration distribution in the thickness direction was measured on the side surfaces of various glass substrates using energy-dispersive X-ray spectroscopy (EDX). Specifically, using an Oxford Instruments X-MaxN, EDX mapping was performed on the thickness direction of the side surfaces of the glass substrates at an acceleration voltage of 10 kV, and the potassium concentration was quantified. Then, in the obtained potassium concentration distribution in the thickness direction of the side surfaces of the glass substrates, the thickness direction was divided into 10 equal regions, from the first main surface side to the second main surface side of the glass substrate, and the average potassium concentration in the 1st, 2nd, and 5th regions was calculated. The average potassium concentration in each region was the arithmetic mean of the measured values ​​at 0.2 μm intervals in the thickness direction. The results are shown in Table 3.

[0417] [Sample Creation Procedure] • Break down the area including the edges of the glass into small pieces of about 1.0 cm. • Embed with epoxy cold embedding resin. • The glass will be polished using a Tegrapol-35 mechanical polishing machine manufactured by Marumoto Struas Co., Ltd. Final polishing conditions: Diamond abrasive particles 1 μm • Pt sputtering is performed after polishing is complete.

[0418] The six-sided tempered glass in Reference Example 3 is the same as the six-sided tempered glass obtained in Comparative Example 1 above. The two-sided tempered glass in Reference Example 4 is the same as the two-sided tempered glass obtained in Examples 1-4 above, and the two-sided tempered glass in Reference Example 8 is the same as the two-sided tempered glass obtained in Example 5 above. Furthermore, the tempered glass in Reference Example 9 is the same as the two-sided tempered glass obtained in Example 9.

[0419] [Table 3]

[0420] Table 3 confirms that if the ratio of the average potassium concentration in region 5 to the average potassium concentration in region 1 is 0.7 or less, then the glass substrate can be considered to be two-sided tempered glass. [Explanation of Symbols]

[0421] 1 ... Glass substrate 1A ... First main surface of the glass substrate 1B ... Second main surface of the glass substrate 1C ... Side of the glass substrate 10 ... Glass laminate 11, 12 ... Resin layer 13… Second resin layer 14… Hard court layer 20…Display device 21… Display panel

Claims

1. It has a first surface, a second surface opposite to the first surface, and a side surface, A glass substrate having a thickness of 15 μm or more and 100 μm or less, and a maximum height Sz of the side surface of 1.5 μm or less, A glass substrate that does not crack or break when the glass substrate is repeatedly bent 180° 200,000 times so that the distance between the opposing short sides of the glass substrate is 12 mm.

2. The glass substrate according to claim 1, wherein the potassium concentration distribution in the thickness direction of the side surface is such that, when the thickness direction is divided into ten equal regions, and these regions are numbered from the first surface to the second surface in order from the first surface to the second surface, the average potassium concentration in the first region is higher than the average potassium concentration in the fifth region.

3. The glass substrate according to claim 2, wherein the ratio of the average potassium concentration in the fifth region to the average potassium concentration in the first region is within the range of 0 to 0.

7.

4. A glass substrate according to any one of claims 1 to 3, used in a flexible display.

5. A glass substrate according to any one of claims 1 to 4, A resin layer disposed on at least one of the first and second surfaces of the glass substrate, A glass laminate having the following characteristics.

6. The glass laminate according to claim 5, wherein the thickness of the resin layer is 5 μm or more and 60 μm or less.

7. The glass laminate according to claim 5 or claim 6, wherein the composite elastic modulus of the resin layer is 4.7 GPa or more.

8. The glass laminate according to any one of claims 5 to 7, wherein the resin layer contains at least one selected from the group consisting of polyimide resin, epoxy resin, polyester, polyurethane, and acrylic resin.

9. The glass laminate according to any one of claims 5 to 8, further comprising a second resin layer covering the side surface of the glass substrate.

10. The glass laminate according to claim 9, wherein the second resin layer contains at least one selected from the group consisting of polyimide resins, epoxy resins, polyesters, and polyurethanes, or contains a cured product of a resin composition containing a polymerizable compound.

11. Display panel and The display panel is positioned on the observer side and comprises a glass substrate according to any one of claims 1 to 4, or a glass laminate according to any one of claims 5 to 10, A display device equipped with the following features.

12. An electronic device comprising the display device described in claim 11.

13. A preparation step for preparing a glass substrate having a thickness of 15 μm or more and 100 μm or less, A resin layer forming step of forming a resin layer on at least one of the first surface and the second surface of the glass substrate, After the resin layer formation step, a cutting step is performed to cut the laminate having the glass substrate and the resin layer, A processing step of processing the cut surface of the glass substrate so that the maximum height Sz of the cut surface of the glass substrate is 1.5 μm or less, It has, A method for manufacturing a glass laminate, wherein the glass substrate does not crack or break when the glass substrate is repeatedly bent 180° 200,000 times so that the distance between the opposing short sides of the glass substrate is 12 mm.

14. The method for manufacturing a glass laminate according to claim 13, further comprising a second resin layer forming step of covering the side surface of the glass substrate with a second resin layer after the cutting step.

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