Laminate and display device

Abstract

To provide a laminate that exhibits favorable flexural durability and impact resistance and that achieves enhanced safety.SOLUTION: A laminate includes a glass substrate 2, a bonding layer 3, and a hard coat film 4 in this order, wherein the hard coat film includes, on the bonding layer side, a base material layer 5 and a hard coat layer 6, the bonding layer is a layer that bonds the glass substrate and the base material layer, a thickness of the glass substrate is 10 μm or more to 100 μm or less, and when a thickness of the hard coat layer is defined as A, a thickness of the base material layer is defined as B, and a thickness of the bonding layer is defined as C, a ratio of (A+B) to C is 3.0 or more to 500 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laminate having a glass substrate and a display device using the same. [Background technology]

[0002] Thin plate glass has excellent hardness and heat resistance, but it is difficult to bend and prone to breaking if dropped. For this reason, in recent years, development has been underway on ultra-thin glass (UTG), which is made thinner so that it can be bent. Among glass types, chemically strengthened glass is said to have particularly high bending resistance. By incorporating expansion stress into the glass surface, minute scratches on the glass surface do not become larger when bent, making the glass less likely to break.

[0003] For example, in the field of displays, flexibility is required. In recent years, the development of flexible displays such as foldable displays, rollable displays, and bendable displays has been actively carried out. In particular, the development of foldable displays, i.e., bendable display devices, has been progressing. The use of ultra-thin glass for such flexible displays has been considered (for example, Patent Documents 1 to 5).

[0004] For example, Patent Document 1 proposes a laminate having a structure in which a glass plate having a thickness of 150 μm or less and a resin film are laminated via an adhesive layer, and which has a bending durability of 10 or more in the following test. Bending durability test: From a stretched state, the laminate is bent 180° in the direction that makes the glass plate face concave so that the bending radius is 3 mm, and then stretched again. This operation counts as one set, and the above operation is performed at a rate of 43 sets per minute. The number of sets until cracks appear in the laminate is used as an index of bending durability.

[0005] Furthermore, for example, Patent Document 2 proposes a laminate having a structure in which a glass plate having a thickness of 150 μm or less and a resin film are laminated via an adhesive layer, and the storage modulus of the adhesive layer at 20°C measured using a dynamic viscoelasticity measuring device is 10 MPa or more, and the bending durability measured by the following test is 10 or more. Bending durability test: From a stretched state, the laminate is bent 180° in the direction that makes the glass plate face concave so that the bending radius is 3 mm, and then stretched again. This operation counts as one set, and the above operation is performed at a rate of 43 sets per minute. The number of sets until cracks appear in the laminate is used as an index of bending durability.

[0006] Furthermore, for example, Patent Document 3 proposes a chemically strengthened, ultra-thin glass article having a thickness of 0.4 mm or less, which has a breaking height (in mm) that exceeds the value obtained by multiplying the thickness (t) of the glass article (t (mm)) by 50, and further has a breaking bending radius (in mm) that is less than the value obtained by multiplying the thickness (t (mm)) of the article by 100,000 and dividing the result by the numerical value (MPa) of the surface compressive stress measured on the first surface, and further includes a laminated polymer layer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-25899 [Patent Document 2] JP 2019-25900 A [Patent Document 3] Special Publication No. 2020-521699 [Patent Document 4] Special Publication No. 2019-504812 [Patent Document 5] Patent No. 6544134 Summary of the Invention [Problem to be solved by the invention]

[0008] Although thinner glass can be bent and has improved bending resistance, it also becomes more fragile, dramatically reducing its impact resistance. If glass is broken by an external impact, not only will the functionality of the display device be reduced if it is used as a cover material for the display device, but the resulting fragments and sharp edges may injure the user's fingertips, etc.

[0009] The present disclosure has been made in view of the above circumstances, and has as its main object to provide a laminate having good flex resistance and impact resistance, and also having improved safety. [Means for solving the problem]

[0010] One embodiment of the present disclosure provides a laminate having a glass substrate, a bonding layer, and a hard coat film in this order, the hard coat film having, from the bonding layer side, a substrate layer and a hard coat layer, the bonding layer being a layer that bonds the glass substrate and the substrate layer, the glass substrate having a thickness of 10 μm or more and 100 μm or less, and where A is the thickness of the hard coat layer, B is the thickness of the substrate layer, and C is the thickness of the bonding layer, the ratio of (A+B) to C is 3.0 or more and 500 or less.

[0011] In the present disclosure, the bonding layer preferably has a composite elastic modulus of 1 MPa or more and 6000 MPa or less.

[0012] In the present disclosure, the glass transition temperature of the bonding layer is preferably −40° C. or higher and 150° C. or lower.

[0013] In the present disclosure, the base layer preferably has a composite elastic modulus of 5.7 GPa or more.

[0014] In the present disclosure, the glass substrate is preferably chemically strengthened glass.

[0015] In the present disclosure, the bonding layer is preferably a pressure-sensitive adhesive layer, a heat-sensitive adhesive layer, or contains a cured product of a curable adhesive composition.

[0016] In the present disclosure, the bonding layer preferably contains at least one resin selected from the group consisting of polyester resin, polyolefin resin, and urethane resin.

[0017] The laminate according to the present disclosure may also have an antireflection layer on the side of the hard coat layer opposite to the substrate layer.

[0018] Furthermore, in the laminate of the present disclosure, it is preferable that cracking, breaking, or peeling does not occur when the laminate is repeatedly bent 200,000 times by 180° so that the surface of the laminate facing the glass substrate is on the outside and the surface of the laminate facing the hard coat layer is on the inside, and the distance between opposing sides of the laminate is 10 mm.

[0019] Another embodiment of the present disclosure provides a laminate having, in this order, a hard coat layer, a base layer, a bonding layer, a glass base material, and a second bonding layer, wherein the bonding layer bonds the glass base material and the base layer, and the second bonding layer bonds the laminate to another member, the glass base material having a thickness of 10 μm or more and 100 μm or less, and the laminate satisfies the following formula (1): 0.001≦{(E1×D1 2 +E2×D2 2 +E3×D3 2 )×E4×D4 2 ×E5×1000} / D5≦3.0 (1) (In the above formula (1), E1 represents the composite elastic modulus (GPa) of the hard coat layer, D1 represents the thickness (mm) of the hard coat layer, E2 represents the composite elastic modulus (GPa) of the base layer, D2 represents the thickness (mm) of the base layer, E3 represents the composite elastic modulus (GPa) of the bonding layer, D3 represents the thickness (mm) of the bonding layer, E4 represents the composite elastic modulus (GPa) of the glass substrate, D4 ​​represents the thickness (mm) of the glass substrate, E5 represents the storage modulus (GPa) of the second bonding layer, and D5 represents the thickness (mm) of the second bonding layer.)

[0020] Another embodiment of the present disclosure is a laminate having, in this order, a base layer, a bonding layer, a glass base material, and a second bonding layer, wherein the bonding layer bonds the glass base material and the base layer, and the second bonding layer bonds the laminate to another member, the glass base material has a thickness of 10 μm or more and 100 μm or less, and the laminate satisfies the following formula (2): 0.001≦{(E2×D2 2 +E3×D3 2 )×E4×D4 2 ×E5×1000} / D5≦3.0 (2) (In the above formula (2), E2 represents the composite elastic modulus (GPa) of the base layer, D2 represents the thickness (mm) of the base layer, E3 represents the composite elastic modulus (GPa) of the bonding layer, D3 represents the thickness (mm) of the bonding layer, E4 represents the composite elastic modulus (GPa) of the glass base, D4 ​​represents the thickness (mm) of the glass base, E5 represents the storage modulus (GPa) of the second bonding layer, and D5 represents the thickness (mm) of the second bonding layer.)

[0021] In the laminate of the present disclosure, the second bonding layer preferably has a glass transition temperature of -50°C or higher and 30°C or lower.

[0022] The laminate of the present disclosure may also have a protective film on the side of the hard coat layer opposite to the substrate layer.

[0023] Another embodiment of the present disclosure provides a display device comprising a display panel and the above-described laminate arranged on the viewer side of the display panel, wherein the laminate is arranged so that the surface of the laminate facing the glass substrate is adjacent to the display panel.

[0024] The display device in the present disclosure is preferably a foldable display. [Effects of the Invention]

[0025] The present disclosure has an effect of providing a laminate having good flex resistance and impact resistance, and also having improved safety. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic cross-sectional view illustrating a laminate according to the present disclosure. [Figure 2] 1 is a schematic cross-sectional view illustrating a laminate according to the present disclosure. [Figure 3] 1 is a schematic cross-sectional view illustrating a laminate according to the present disclosure. [Figure 4] 1 is a schematic cross-sectional view illustrating a laminate according to the present disclosure. [Figure 5] FIG. 1 is a schematic diagram for explaining a dynamic bending test. [Figure 6] FIG. 1 is a schematic diagram for explaining a static bending test. [Figure 7] 1 is a schematic cross-sectional view illustrating a laminate according to the present disclosure. [Figure 8] 1 is a schematic cross-sectional view illustrating a laminate according to the present disclosure. [Figure 9] 1 is a schematic cross-sectional view illustrating a display device according to the present disclosure. [Figure 10] 1 is a graph showing the relationship between the value of the middle side of equation (1) and the test height in a pen drop test. [Figure 11] 1 is a graph showing the relationship between the value of the middle side of equation (2) and the test height in a pen drop test. DETAILED DESCRIPTION OF THE INVENTION

[0027] Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. Furthermore, to clarify the explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the preceding drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0028] In this specification, when describing a mode in which another component is placed on a certain component, the terms "above" or "below" are used, unless otherwise specified, to include both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween. Also, in this specification, when describing a mode in which another component is placed on the surface of a certain component, the terms "on the surface side" or "on the surface" are used, unless otherwise specified, to include both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween.

[0029] The laminate and display device according to the present disclosure will be described in detail below.

[0030] A. Laminate The laminate in the present disclosure has three embodiments, each of which will be described below.

[0031] I. First embodiment The inventors of the present disclosure conducted extensive research into laminates having glass substrates and found that by disposing a resin layer on the surface of a thin glass substrate and further increasing the thickness of the resin layer, cracking of the glass substrate can be suppressed and impact resistance can be improved. However, it was found that when a resin composition is applied to the surface of a glass substrate to form a relatively thick resin layer, the difference in shrinkage between the glass substrate and the resin layer can be significantly affected during heating or curing after application of the resin composition, resulting in curling. The inventors of the present disclosure then conducted further research and found that by forming a resin layer into a film in advance and bonding the resin film to the surface of a thin glass substrate via a bonding layer, it is possible to suppress curling and further improve impact resistance. However, it was found that in such laminates, the surface hardness of the resin film side of the laminate can be reduced, resulting in reduced scratch resistance.

[0032] The present embodiment has been made in view of the above circumstances, and aims to provide a laminate having good flex resistance, impact resistance, and scratch resistance, and also having improved safety.

[0033] A first embodiment of the laminate in the present disclosure has a glass substrate, a bonding layer, and a hard coat film in this order, and the hard coat film has, from the bonding layer side, a base layer and a hard coat layer, and the thickness of the glass substrate is 10 μm to 100 μm, and when the thickness of the hard coat layer is A, the thickness of the base layer is B, and the thickness of the bonding layer is C, the thickness ratio (A+B) / C is 3.0 to 500. That is, the laminate of this embodiment has a glass substrate, a bonding layer, and a hard coat film in this order, and the hard coat film has, from the bonding layer side, a base layer and a hard coat layer, and the bonding layer is a layer that bonds the glass substrate and the base layer, and the thickness of the glass substrate is 10 μm to 100 μm, and when the thickness of the hard coat layer is A, the thickness of the base layer is B, and the thickness of the bonding layer is C, the ratio of (A+B) to C is 3.0 to 500.

[0034] Fig. 1 is a schematic cross-sectional view showing an example of a laminate in this embodiment. As shown in Fig. 1, laminate 1 has a glass substrate 2 having a predetermined thickness, a bonding layer 3, and a hard coat film 4 in this order, and hard coat film 4 has, from the bonding layer 3 side, a base layer 5 and a hard coat layer 6. Furthermore, when the thickness of hard coat layer 6 is A, the thickness of base layer 5 is B, and the thickness of bonding layer 3 is C, the thickness ratio (A+B) / C is within a predetermined range.

[0035] In the laminate of this embodiment, the glass substrate has a thickness of a predetermined value or less and is thin, so that the bending resistance can be improved. On the other hand, since the glass substrate has a thickness of a predetermined value or less and is thin, there is a concern that it is easily broken and has low impact resistance. In contrast, in this embodiment, a hard coat film is disposed on one side of the glass substrate via a bonding layer, so that the impact resistance can be improved while maintaining good bending resistance.

[0036] Furthermore, in the laminate of this embodiment, when the thickness of the hard coat layer is A, the thickness of the base layer is B, and the thickness of the bonding layer is C, by ensuring that the thickness ratio (A+B) / C is within a predetermined range, the surface hardness of the hard coat film side of the laminate can be increased, and scratch resistance can be improved. The reason for this is presumed to be as follows.

[0037] In this embodiment, the thickness ratio (A+B) / C is 3.0 or more, and the thickness of the bonding layer is relatively thin compared to the total thickness of the hard coat layer and the substrate layer. The bonding layer usually has a lower hardness than the glass substrate and the hard coat layer, but the relatively thin thickness of the bonding layer can reduce the influence of the hardness of the bonding layer, and can increase the surface hardness of the hard coat film side of the laminate. As a result, scratch resistance can be improved.

[0038] As a result of intensive research, the inventors of the present disclosure have found that even when the thickness of the bonding layer is relatively thin, the surface hardness of the hard coat film side of the laminate may be low, as described in the examples and comparative examples below. They have also found that in order to increase the surface hardness of the hard coat film side of the laminate, it is important to make the thickness of the bonding layer relatively thin, that is, to set the thickness ratio (A+B) / C to a predetermined value or more.

[0039] Thus, in this embodiment, it is possible to achieve both impact resistance and scratch resistance while maintaining good bending resistance. Moreover, even if the glass substrate in the laminate is broken, the risk of injury to the human body can be reduced, making it a highly safe laminate. Therefore, the laminate in this embodiment can be bent and used for a wide variety of applications. The laminate in this embodiment can be used, for example, in a wide variety of display devices, and specifically, can be used as a member for a foldable display.

[0040] Each component of the laminate in this embodiment will be described below.

[0041] 1. Thickness ratio In this embodiment, when the thickness of the hard coat layer is A, the thickness of the base layer is B, and the thickness of the bonding layer is C, the thickness ratio (A+B) / C is 3.0 or more, preferably 4.0 or more, and more preferably 5 or more. By having the thickness ratio within the above range, the surface hardness of the hard coat film side of the laminate can be increased, thereby improving scratch resistance. On the other hand, the thickness ratio (A+B) / C is 500 or less, preferably 150 or less, more preferably 100 or less, even more preferably 70 or less, and particularly preferably 40 or less. If the thickness ratio is too large, the thickness of the bonding layer becomes relatively very thin, which may weaken the adhesion and may result in a decrease in flex resistance, particularly dynamic flex resistance, or a decrease in impact resistance. The thickness ratio (A+B) / C is 3.0 or more and 500 or less, preferably 4.0 or more and 150 or less, more preferably 5 or more and 100 or less, even more preferably 5 or more and 70 or less, and particularly preferably 5 or more and 40 or less.

[0042] The thickness of the hard coat layer is not particularly limited as long as it satisfies the above thickness ratio, but is appropriately selected depending on the function of the hard coat layer and the use of the laminate. The thickness of the hard coat layer is, for example, 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. When the thickness of the hard coat layer is within the above range, the surface hardness of the hard coat film side of the laminate can be increased, and scratch resistance can be improved. On the other hand, the thickness of the hard coat layer is, for example, 50 μm or less, preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less. When the thickness of the hard coat layer is within the above range, good flex resistance can be obtained. The thickness of the hard coat layer is, for example, 1 μm or more and 50 μm or less, preferably 3 μm or more and 30 μm or less, more preferably 5 μm or more and 25 μm or less, and even more preferably 10 μm or more and 20 μm or less.

[0043] The thickness of the substrate layer is not particularly limited as long as it satisfies the above thickness ratio, but is, for example, 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. Having the substrate layer thickness within the above range can improve impact resistance. On the other hand, the thickness of the substrate layer is, for example, 150 μm or less, preferably 125 μm or less, more preferably 100 μm or less, and even more preferably 80 μm or less. Having the substrate layer thickness within the above range can achieve good flex resistance. The thickness of the substrate layer is, for example, 10 μm or more and 150 μm or less, preferably 15 μm or more and 125 μm or less, more preferably 20 μm or more and 100 μm or less, and even more preferably 25 μm or more and 85 μm or less.

[0044] The thickness of the bonding layer is not particularly limited as long as it satisfies the above thickness ratio, but is, for example, 25 μm or less, preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. Having a bonding layer thickness within the above range increases the surface hardness of the hard coat film side of the laminate, improving scratch resistance. Furthermore, having a relatively thin bonding layer within the above range allows the glass texture and tactile feel of the glass substrate to be maintained. Meanwhile, the thickness of the bonding layer is, for example, 0.2 μm or more, preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, and particularly preferably 2.0 μm or more. If the bonding layer is too thin, adhesion may be weakened, resulting in reduced flex resistance, particularly dynamic flex resistance, and reduced impact resistance. The thickness of the bonding layer is, for example, 0.2 μm to 25 μm, preferably 0.5 μm to 20 μm, more preferably 1.0 μm to 15 μm, even more preferably 1.5 μm to 10 μm, and particularly preferably 2.0 μm to 10 μm.

[0045] Here, the thickness of each layer can be the arithmetic mean value of the thicknesses of 10 arbitrary locations measured on a cross section of the laminate in the thickness direction observed with a scanning electron microscope (SEM). The specific method for taking cross-sectional photographs is as follows. First, the laminate is cut into a 2 cm × 2 cm block, embedded in an embedding resin to create a block, and a cross section is prepared using a polishing machine. A TegraPol-35 manufactured by Struers can be used as the polishing machine. Then, a cross-sectional photograph of the measurement sample is taken using a scanning electron microscope. A Hitachi High-Technologies S-4800 can be used as the scanning electron microscope. When taking cross-sectional photographs using a scanning electron microscope (Hitachi High-Technologies S-4800), the detector is set to "Lower," the accelerating voltage to "3 kV," and the emission current to "10 μA" for cross-sectional observation. The magnification is adjusted appropriately within the range of 100x to 100,000x, preferably 1,000x to 50,000x, and more preferably 5,000x to 10,000x, by adjusting the focus and observing whether the individual layers can be distinguished in terms of contrast and brightness. When taking cross-sectional photographs using a scanning electron microscope (S-4800 manufactured by Hitachi High-Technologies Corporation), the beam monitor aperture may be set to "1," the objective lens aperture to "3," and the working distance to "8 mm." The contrast of the interface may be difficult to discern at high magnifications. In such cases, observations are also performed at low magnifications. For example, observations are performed at two magnifications, such as 2,000x and 10,000x, or 5,000x and 20,000x. The arithmetic mean values ​​are then calculated for the cross-sectional photographs at both magnifications, and these mean values ​​are used to determine the thickness of each layer. Unless otherwise specified, the same method can be used to measure the thickness of other layers in the laminate.

[0046] 2.Joining layer The bonding layer in this embodiment is a layer disposed between the glass substrate and the hard coat film, and serves to bond the glass substrate and the hard coat film together.

[0047] The material used for the bonding layer is not particularly limited as long as it is a material that can bond the glass substrate and the hard coat film, and examples thereof include pressure-sensitive adhesives such as optically clear adhesives (OCA), heat-sensitive adhesives such as heat seal agents, curable adhesives, etc. These may be used alone or in combination of two or more.

[0048] Examples of pressure-sensitive adhesives such as optically transparent adhesives (OCA) include acrylic adhesives, urethane adhesives, silicone adhesives, epoxy adhesives, vinyl acetate adhesives, and polyvinyl acetal adhesives such as polyvinyl butyral (PVB).

[0049] As a heat-sensitive adhesive such as a heat-sealing agent, for example, a heat-weldable thermoplastic resin can be used. Such thermoplastic resins are not particularly limited, and examples thereof include acrylic resins, vinyl chloride-vinyl acetate copolymers, polyamide resins, polyester resins, polyester urethane resins, chlorinated polypropylene, chlorinated rubber, urethane resins, epoxy resins, styrene resins, polyolefin resins, silicone resins, polyvinyl acetal resins such as polyvinyl butyral (PVB), and polyether urethane resins. These thermoplastic resins may be used alone or in combination of two or more.

[0050] The heat-sensitive adhesive composition may further contain a curing agent. This can improve heat resistance and adhesiveness. The addition of a curing agent can also adjust the composite modulus of the bonding layer, which will be described later. To obtain a bonding layer with a desired composite modulus, it is preferable to add a curing agent appropriately depending on the properties of the thermoplastic resin. Examples of curing agents include isocyanate-based curing agents, epoxy-based curing agents, and melamine-based curing agents. The curing agents may be used alone or in combination of two or more. When the heat-sensitive adhesive composition contains a curing agent, the bonding layer will contain a cured product of the heat-sensitive adhesive composition.

[0051] The heat-sensitive adhesive composition may also contain additives as needed. Examples of additives include light stabilizers, ultraviolet absorbers, infrared absorbers, antioxidants, plasticizers, coupling agents, defoamers, fillers, inorganic or organic particles for adjusting the refractive index, antistatic agents, colorants such as blue pigments and purple pigments, leveling agents, surfactants, lubricants, various sensitizers, flame retardants, adhesion promoters, polymerization inhibitors, and surface modifiers. These additives can be appropriately selected from commonly used additives. The content of the additives can be appropriately set. In particular, the heat-sensitive adhesive composition preferably contains a silane coupling agent to enhance adhesion to glass substrates.

[0052] Examples of the curable adhesive include a thermosetting adhesive and an ultraviolet curable adhesive.

[0053] A thermosetting adhesive is an adhesive that hardens when heated, and examples of thermosetting adhesives include epoxy adhesives, acrylic adhesives, urethane adhesives, polyester adhesives, and silicone adhesives.

[0054] The ultraviolet curing adhesive is an adhesive that hardens when irradiated with ultraviolet light, and examples of the ultraviolet curing adhesive include epoxy adhesives, acrylic adhesives, and urethane acrylate adhesives.

[0055] The curable adhesive composition may also contain additives as needed. Examples of additives include light stabilizers, ultraviolet absorbers, infrared absorbers, antioxidants, plasticizers, coupling agents, antifoaming agents, fillers, inorganic or organic particles for adjusting the refractive index, antistatic agents, colorants such as blue pigments and purple pigments, leveling agents, surfactants, lubricants, various sensitizers, flame retardants, adhesion promoters, polymerization inhibitors, and surface modifiers. These additives can be appropriately selected from commonly used additives. The content of the additives can be appropriately set.

[0056] Among these, the material used for the bonding layer is preferably a heat-sensitive adhesive or a curable adhesive, and more preferably a heat-sealing agent, a UV-curable adhesive, or a thermosetting adhesive. That is, the bonding layer is preferably a heat-sensitive adhesive layer or contains a cured product of a curable adhesive composition, and more preferably a heat-sealing layer or contains a cured product of a UV-curable adhesive composition or a thermosetting adhesive composition. By using a heat-sealing agent, a UV-curable adhesive, or a thermosetting adhesive, a bonding layer satisfying the composite elastic modulus described below can be obtained, and the glass transition temperature of the bonding layer described below can be set to 0°C or higher. Furthermore, in the case of optically transparent adhesives (OCA), OCA films are used. However, some OCA films have surface irregularities. Using such OCA films can cause screen fluctuations due to the irregularities, potentially impairing the texture and feel of the glass provided by the glass substrate. In contrast, using a heat-sensitive adhesive or a curable adhesive can prevent such defects.

[0057] The bonding layer preferably contains at least one resin selected from the group consisting of polyester resin, polyolefin resin, and urethane resin. Among these, the bonding layer more preferably contains polyester resin. Urethane resins include polyester urethane resin and polyether urethane resin. Bonding layers containing such materials can easily adjust the composite elastic modulus (described later) to a preferred range.

[0058] The composite modulus of the bonding layer is, for example, preferably 1 MPa or more, more preferably 10 MPa or more, and even more preferably 20 MPa or more. When the composite modulus of the bonding layer is within the above range and has a certain degree of hardness, the surface hardness of the surface on the hard coat film side of the laminate can be increased, improving scratch resistance and impact resistance. On the other hand, the composite modulus of the bonding layer is, for example, preferably 6000 MPa or less, more preferably 5500 MPa or less, and even more preferably 4500 MPa or less. If the composite modulus of the bonding layer is too high, the adhesiveness may be weakened or the hardness may be too high, making it difficult to bend, and the bending resistance, particularly dynamic bending resistance, may be reduced. The composite modulus of the bonding layer is, for example, preferably 1 MPa or more and 6000 MPa or less, more preferably 10 MPa or more and 5500 MPa or less, even more preferably 20 MPa or more and 4500 MPa or less, and particularly preferably 25 MPa or more and 4000 MPa or less.

[0059] Here, the composite elastic modulus of the bonding layer is the indentation hardness (H IT ) when measuring the contact projection area A p "Indentation hardness" is a value determined from the load-displacement curve from loading to unloading of the indenter, obtained by hardness measurement using the nanoindentation method. The composite elastic modulus of the bonding layer is an elastic modulus that includes the elastic deformation of the bonding layer and the elastic deformation of the indenter.

[0060] Indentation hardness (H ITThe measurement of the dimensional relationship (D) is performed on the measurement sample using a BRUKER TI950 TriboIndenter. Specifically, a 1 mm x 10 mm cut-out laminate is embedded in an embedding resin to prepare a block. A uniform, hole-free section with a thickness of 50 nm to 100 nm is then cut from this block using a standard sectioning method. An Ultramicrotome EM UC7 (Leica Microsystems) or similar instrument can be used to prepare the section. The remaining block from which the uniform, hole-free section is cut serves as the measurement sample. Next, a Berkovich indenter (triangular pyramid, BRUKER TI-0039) is pressed vertically into the center of the cross section of the bonding layer for 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 hard coat film and the side edges of the bonding layer, the Berkovich indenter is pressed into a portion of the bonding layer 500 nm away from the interface between the glass substrate and the bonding layer toward the center of the bonding layer, 500 nm away from the interface between the substrate layer of the hard coat film and the bonding layer toward the center of the bonding layer, and 500 nm away from each of the two ends of the bonding layer toward the center of the bonding layer. After that, the residual stress is relaxed by holding it constant, and then the load is released over 10 seconds, and the maximum load after relaxation is measured, and this maximum load P max (μN) and contact projection area A p (nm 2 ) and P max / A p The indentation hardness (H IT The above contact projected area is the contact projected area corrected for the indenter tip curvature by the Oliver-Pharr method using a standard sample of fused quartz (5-0098 manufactured by BRUKER). Indentation hardness (H IT) is the arithmetic mean value obtained by measuring at 10 locations. If any of the measured values ​​deviate from the arithmetic mean value by more than ±20%, those measured values ​​shall be excluded and remeasured. Whether or not any of the measured values ​​deviate from the arithmetic mean value by more than ±20% shall be determined by whether the value (%) calculated by (AB) / B x 100, where A is the measured value and B is the arithmetic mean value, is more than ±20%.

[0061] (Measurement condition 1) ·Loading speed: 2.5μN / sec ·Holding time: 5 seconds ·Load unloading speed: 2.5μN / sec ·Measurement temperature: 25℃

[0062] When measuring indentation hardness under the above measurement condition 1, if the indentation depth at the maximum load is 500 nm or more, the measurement should be performed under the following measurement condition 2. As mentioned above, in measuring indentation hardness, the bonding layer is indented for 10 seconds, so the maximum load under measurement condition 1 is 25 μN, and under measurement condition 2 it is 5 μN.

[0063] (Measurement condition 2) ·Loading speed: 0.5μN / sec ·Holding time: 5 seconds ·Load unloading speed: 0.5μN / sec ·Measurement temperature: 25℃

[0064] Composite elastic modulus of the bonding layer E r is the contact projected area A obtained during the indentation hardness measurement using the following formula (3). p The composite elastic modulus is determined by measuring the indentation hardness at 10 points, calculating the composite elastic modulus each time, and taking the arithmetic mean value of the composite elastic moduli obtained at the 10 points.

[0065]

number

[0066] (In the above formula (3), A p is the contact projected area, and E r is the composite elastic modulus of the bonding layer, and S is the contact stiffness.)

[0067] The composite elastic modulus of the bonding layer can be adjusted by, for example, the type and composition of the material contained in the bonding layer.

[0068] The glass transition temperature of the bonding layer is preferably, for example, -40°C or higher, more preferably -30°C or higher, even more preferably -10°C or higher, even more preferably 0°C or higher, and particularly preferably 20°C or higher. When the glass transition temperature of the bonding layer is within the above range, a bonding layer satisfying the above-mentioned composite elastic modulus can be easily obtained. Furthermore, when the glass transition temperature of the bonding layer is 0°C or higher, scratch resistance and impact resistance can be further improved. On the other hand, the glass transition temperature of the bonding layer is, for example, preferably 150°C or lower, more preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower. If the glass transition temperature of the bonding layer is too high, adhesiveness may not be ensured. The glass transition temperature of the bonding layer is, for example, preferably -40°C or higher and 150°C or lower, more preferably -30°C or higher and 150°C or lower, more preferably -10°C or higher and 140°C or lower, particularly preferably 0°C or higher and 130°C or lower, and most preferably 0°C or higher and 120°C or lower. The glass transition temperature of the bonding layer is also preferably, for example, from −40° C. to 25° C. and from 50° C. to 150° C. A laminate that can withstand use in high-temperature, high-humidity, and low-temperature environments can be obtained.

[0069] Here, the glass transition temperature of the bonding layer refers to a value measured by a method based on the peak-top value of the loss tangent (tanδ) (DMA method). When measuring the storage modulus E', loss modulus E", and loss tangent tanδ of the bonding layer using a dynamic viscoelasticity measuring device (DMA), the bonding layer is first punched out to 15 mm x 200 mm. In this case, a test piece of the bonding layer can also be obtained by preparing a solution by dissolving or melting the bonding layer material, applying the solution to a substrate, drying, and then peeling the film from the substrate. The solvent is appropriately selected depending on the bonding layer material, and examples include ethyl acetate. In addition, when preparing the solution, the bonding layer material may be heated and dissolved as appropriate. The substrate can be, for example, a 15 mm x 200 mm die-cast bonding layer. A Naflon® sheet (300 mm × 300 mm × 1 mm thick) can be used. The bonding layer is then sampled into a cylindrical shape approximately φ5 mm × 5 mm high. The bonding layer can be rolled up to form a cylindrical shape. The cylindrical measurement sample is attached between the compression fixtures (parallel plates φ8 mm) of a dynamic viscoelasticity measuring device. A compressive load is then applied, and a longitudinal vibration at a frequency of 1 Hz is given. Dynamic viscoelasticity measurements are performed in the range of −50°C to 200°C, and the storage modulus E′, loss modulus E″, and loss tangent tanδ of the bonding layer are measured at each temperature. The glass transition temperature of the bonding layer is defined as the temperature at which the loss tangent tanδ peaks in the range of −50°C to 200°C. An example of a dynamic viscoelasticity measuring device that can be used is the RSAIII manufactured by TA Instruments. The specific measurement conditions for the above method are shown below.

[0070] (Conditions for measuring glass transition temperature) Measurement sample: φ5mm x height 5mm cylindrical Measurement jig: Compression (parallel plate) Measurement mode: Temperature dependent (Temperature range: -50°C to 200°C, Heating rate: 5°C / min) Frequency: 1Hz

[0071] When the laminate of this embodiment is used in, for example, a display device, the bonding layer preferably has transparency. Specifically, the total light transmittance of the bonding layer is preferably 80% or more, more preferably 85% or more, and even more preferably 88% or more.

[0072] Here, the total light transmittance of the bonding layer can be measured in accordance with JIS K7361-1, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory Co., Ltd. The same method for measuring the total light transmittance of the other layers can be used hereinafter.

[0073] The haze of the bonding layer is preferably, for example, 2% or less, more preferably 1.5% or less, and even more preferably 1% or less.

[0074] The haze of the bonding layer can be measured in accordance with JIS K-7136, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory. The same method can be used to measure the haze of other layers.

[0075] The method for bonding a glass substrate and a hard coat film via a bonding layer is appropriately selected depending on the material used for the bonding layer. For example, in the case of a pressure-sensitive adhesive such as an optically transparent adhesive (OCA), a film-like pressure-sensitive adhesive layer can be used to bond the hard coat film and the glass substrate via the film-like pressure-sensitive adhesive layer. In the case of a heat-sensitive adhesive such as a heat-sealing agent, a heat-sensitive adhesive composition can be applied to the substrate layer side of the hard coat film or one side of the glass substrate, dried to form a heat-sensitive adhesive layer, and then the hard coat film and the glass substrate can be superimposed via the heat-sensitive adhesive layer and heated to thermally weld them together via the heat-sensitive adhesive layer. In this case, the heating temperature is preferably equal to or higher than the glass transition temperature of the heat-sensitive adhesive layer. In the case of a thermosetting adhesive, for example, a thermosetting adhesive composition can be applied to the substrate layer side of the hard coat film or one side of the glass substrate, dried to form a heat-curable adhesive layer, and then the hard coat film and the glass substrate can be superimposed via the heat-curable adhesive layer and heated to harden the heat-curable adhesive layer, thereby bonding them together. Furthermore, for example, in the case of an ultraviolet-curable adhesive, an ultraviolet-curable adhesive composition can be applied to the surface of the hard coat film on the substrate layer side or one surface of the glass substrate, dried to form an ultraviolet-curable adhesive layer, and then the hard coat film and the glass substrate can be superimposed with the ultraviolet-curable adhesive layer interposed therebetween, and ultraviolet light can be irradiated to cure the ultraviolet-curable adhesive layer, thereby bonding the two together.

[0076] When preparing the adhesive composition, a resin may be used in a solid form such as a pellet or sheet. In this case, the resin and a solvent may be heated in advance to dissolve the resin in the solvent, thereby preparing a resin solution, and then this resin solution may be used to prepare the adhesive composition.

[0077] 3.Hard coat film The hard coat film in this embodiment has, from the bonding layer side, a base layer and a hard coat layer.

[0078] Each component of the hard coat film will be described below.

[0079] (1) Hard Coat Layer The hard coat layer in this embodiment is a layer for increasing the surface hardness, and by providing the hard coat layer, scratch resistance can be improved.

[0080] (a) Characteristics of the hard coat layer Here, the "hard coat layer" refers to a member for increasing the surface hardness, and specifically refers to a layer having a hard coat layer in the laminate of this embodiment, which exhibits a hardness of "H" or higher when subjected to a pencil hardness test specified in JIS K 5600-5-4 (1999).

[0081] The pencil hardness of the surface of the hard coat layer side of the laminate in this embodiment is preferably H or more, more preferably 2H or more, even more preferably 3H or more, particularly preferably 4H or more, and most preferably 5H or more.

[0082] Here, pencil hardness is measured by 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 surface of the hard coat layer side of the laminate, and the highest pencil hardness that does not cause scratches is evaluated. Measurement conditions can be an angle of 45°, a load of 1 kg, a speed of 0.5 mm / sec to 1 mm / sec, and a temperature of 23±2°C. As a pencil hardness tester, for example, a pencil scratch coating hardness tester manufactured by Toyo Seiki Co., Ltd. can be used.

[0083] (b) Hard Coat Layer Structure The hard coat layer may be a single layer or may have a multi-layer structure of two or more layers. When the hard coat layer has a multi-layer structure, in order to improve the surface hardness and to achieve a good balance between the flex resistance and the elastic modulus, the hard coat layer may have a layer for satisfying the pencil hardness and a layer for satisfying the dynamic flex test (a layer for satisfying the abrasion resistance).

[0084] (c) Hard Coat Layer Material Examples of materials for the hard coat layer include cured resins. Specifically, the hard coat layer preferably contains a cured resin composition containing a polymerizable compound. The cured resin composition containing a polymerizable compound can be obtained by polymerizing the polymerizable compound using a polymerization initiator as needed, using a known method.

[0085] (i) Polymerizable compound The polymerizable compound has at least one polymerizable functional group in the molecule, and may be, for example, at least one of a radical polymerizable compound and a cation polymerizable compound.

[0086] The radical polymerizable compound is a compound having a radical polymerizable group. The radical polymerizable group of 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 groups containing a carbon-carbon unsaturated double bond, and specific examples thereof include a vinyl group and a (meth)acryloyl group. When the radical polymerizable compound has two or more radical polymerizable groups, these radical polymerizable groups may be the same or different.

[0087] The number of radically polymerizable groups that the radically polymerizable compound has in one molecule is preferably 2 or more, more preferably 3 or more, from the viewpoint of improving the hardness of the hard coat layer.

[0088] Among radical polymerizable compounds, compounds having a (meth)acryloyl group are preferred in terms of high reactivity. For example, polyfunctional (meth)acrylate monomers and oligomers having several (meth)acryloyl groups in the molecule and molecular weights of several hundred to several thousand, such as urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, polyfluoroalkyl (meth)acrylate, and silicone (meth)acrylate, are preferably used. Polyfunctional (meth)acrylate polymers having two or more (meth)acryloyl groups in the side chains of the acrylate polymer are also preferably used. Among these, polyfunctional (meth)acrylate monomers having two or more (meth)acryloyl groups in one molecule are preferably used. By including a cured product of a polyfunctional (meth)acrylate monomer in the hard coat layer, the hardness of the hard coat layer can be improved, and adhesion can also be improved. Also, polyfunctional (meth)acrylate oligomers or polymers having two or more (meth)acryloyl groups in one molecule can be preferably used. When the hard coat layer contains a cured product of the polyfunctional (meth)acrylate oligomer or polymer, the hardness and flex resistance of the hard coat layer can be improved, and further, the adhesion can be improved.

[0089] In this specification, (meth)acryloyl refers to both acryloyl and methacryloyl, and (meth)acrylate refers to both acrylate and methacrylate.

[0090] Specific examples of polyfunctional (meth)acrylate monomers include those described in JP-A-2019-132930. Among these, from the viewpoints of high reactivity, improved hardness of the hard coat layer, and adhesion, those having 3 to 6 (meth)acryloyl groups in one molecule are preferred. 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. can be preferably used, and in particular, at least one selected from pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexaacrylate, and those modified with PO, EO, or caprolactone is preferred.

[0091] The resin composition may contain a monofunctional (meth)acrylate monomer as a radical polymerizable compound to adjust hardness and viscosity, improve adhesion, etc. Specific examples of the monofunctional (meth)acrylate monomer include those described in JP 2019-132930 A.

[0092] The cationically polymerizable compound is a compound having a cationically polymerizable group. The cationically polymerizable group of the cationically polymerizable compound is not particularly limited as long as it is a functional group capable of causing a cationic polymerization reaction, and examples thereof include an epoxy group, an oxetanyl group, and a vinyl ether group. When the cationically polymerizable compound has two or more cationically polymerizable groups, these cationically polymerizable groups may be the same or different.

[0093] The number of cationically polymerizable groups that the cationically polymerizable compound has in one molecule is preferably 2 or more, more preferably 3 or more, from the viewpoint of improving the hardness of the hard coat layer.

[0094] Among the cationically polymerizable compounds, compounds having at least one of an epoxy group and an oxetanyl group as the cationically polymerizable group are preferred, and compounds having two or more of at least one of an epoxy group and an oxetanyl group per molecule are more preferred. Cyclic ether groups such as epoxy groups and oxetanyl groups are preferred because they cause minimal shrinkage during polymerization. Among cyclic ether groups, compounds having an epoxy group are readily available in a variety of structures, do not adversely affect the durability of the resulting hard coat layer, and are advantageous in that their compatibility with radically polymerizable compounds is easily controlled. Among cyclic ether groups, oxetanyl groups have a higher degree of polymerization and lower toxicity than epoxy groups. When the resulting hard coat layer is combined with a compound having an epoxy group, they accelerate the network formation rate from the cationically polymerizable compound in the coating film, forming an independent network without leaving unreacted monomers in the film, even in regions where the radically polymerizable compound coexists.

[0095] Examples of the cationically polymerizable compound having an epoxy group include alicyclic epoxy resins obtained by epoxidizing polyglycidyl ethers of polyhydric alcohols having an alicyclic ring or cyclohexene ring- or cyclopentene ring-containing compounds 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 glycidyl (meth)acrylate homopolymers and copolymers; and glycidyl ether-type epoxy resins derived from bisphenols, such as bisphenol A, bisphenol F, and hydrogenated bisphenol A, or derivatives thereof, such as alkylene oxide adducts or caprolactone adducts, and novolac epoxy resins.

[0096] Specific examples of alicyclic epoxy resins, glycidyl ether epoxy resins, and cationically polymerizable compounds having an oxetanyl group include those described in JP-A-2018-104682.

[0097] The cured product of the resin composition containing the polymerizable compound contained in the hard coat layer can be analyzed using a Fourier transform infrared spectrophotometer (FTIR), a pyrolysis gas chromatograph (GC-MS), or the decomposition product of the polymer can be analyzed using a combination of high performance liquid chromatography, a gas chromatograph mass spectrometer, NMR, elemental analysis, XPS / ESCA, and TOF-SIMS.

[0098] (ii) Polymerization initiator The resin composition may contain a polymerization initiator as needed. The polymerization initiator may be appropriately selected from radical polymerization initiators, cationic polymerization initiators, radical and cationic polymerization initiators, etc. These polymerization initiators are decomposed by at least one of light irradiation and heating to generate radicals or cations, thereby promoting 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.

[0099] Specific examples of radical polymerization initiators and cationic polymerization initiators include those described in JP-A-2018-104682.

[0100] (iii) particles The hard coat layer preferably contains inorganic or organic particles, more preferably inorganic fine particles, which can improve the hardness of the hard coat layer.

[0101] Examples of inorganic particles include metal oxide particles such as silica (SiO), 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, and at least one selected from silica particles and aluminum oxide particles is more preferred, with silica particles being even more preferred because excellent hardness can be obtained.

[0102] The inorganic particles are preferably reactive inorganic particles having, at least on a part of their surface, photoreactive reactive functional groups capable of forming covalent bonds by crosslinking with each other or with at least one polymerizable compound. The hardness of the hard coat layer can be further improved by crosslinking with each other or with at least one of a radical polymerizable compound and a cation polymerizable compound.

[0103] The reactive inorganic particles have at least a portion of their surface coated with an organic component and have reactive functional groups on their surface introduced by the organic component. Examples of the reactive functional groups include polymerizable unsaturated groups, and more preferably photocurable unsaturated groups. Examples of the reactive functional groups include ethylenically unsaturated bonds such as (meth)acryloyl groups, vinyl groups, and allyl groups, and epoxy groups.

[0104] The reactive silica particles are not particularly limited, and conventionally known ones can be used, such as the reactive silica particles described in JP 2008-165040 A. Commercially available reactive silica particles include MIBK-SD, MIBK-SDMS, MIBK-SDL, and MIBK-SDZL manufactured by Nissan Chemical Industries, Ltd., and V8802 and V8803 manufactured by JGC Catalysts and Chemicals, Ltd.

[0105] In addition, silica particles may be spherical silica particles, but preferably irregular silica particles.Spherical silica particles and irregular silica particles may be mixed.In this specification, irregular silica particles refer to silica particles with a shape that has random potato-like irregularities on the surface.Since irregular silica particles have a larger surface area than spherical silica particles, by including such irregular silica particles, the contact area with the resin component etc. is increased, and the hardness of the hard coat layer can be improved.

[0106] Whether or not the silica particles are irregular shaped can be confirmed by observing the cross section of the hard coat layer with an electron microscope.

[0107] The average particle size of the inorganic particles is preferably 5 nm or more, more preferably 10 nm or more, from the viewpoint of improving hardness. If the average particle size of the inorganic particles is too small, it may be difficult to produce the particles and the particles may be prone to agglomeration. Furthermore, from the viewpoint of transparency, the average particle size of the inorganic particles is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. If the average particle size of the inorganic particles is too large, there is a risk that large irregularities may be formed in the hard coat layer or that the haze may be high.

[0108] Here, the average particle size of the inorganic particles can be measured by observing the cross section of the hard coat layer with an electron microscope, and the average particle size is the average of the particle sizes of 10 arbitrarily selected particles. The average particle size of the irregular silica particles is the average of the maximum (longer diameter) and minimum (minor diameter) distances between two points on the periphery of the irregular silica particles that appear in the cross section of the hard coat layer with a microscope.

[0109] The hardness of the hard coat layer can be controlled by adjusting the size and content of the inorganic particles. For example, the content of silica particles is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 50 parts by mass or more, relative to 100 parts by mass of the polymerizable compound. When the content of silica particles is within the above range, the hardness of the hard coat layer can be increased. Furthermore, the content of silica particles is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, and even more preferably 100 parts by mass or less, relative to 100 parts by mass of the polymerizable compound. When the content of silica particles is within the above range, good flex resistance can be obtained. For example, the content of silica particles is preferably 25 parts by mass or more and 150 parts by mass or less, more preferably 30 parts by mass or more and 120 parts by mass or less, and even more preferably 50 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the polymerizable compound.

[0110] (iv) ultraviolet absorber The hard coat layer may contain an ultraviolet absorber. This can suppress deterioration of the substrate layer due to ultraviolet rays. In particular, when the substrate layer contains polyimide, it can suppress color change over time in the substrate layer containing polyimide. Furthermore, in a display device including the laminate, it can suppress deterioration due to ultraviolet rays of components arranged on the display panel side of the laminate, such as polarizers.

[0111] The ultraviolet absorber contained in the hard coat layer preferably has an absorption wavelength peak in absorbance measurement of 300 nm to 390 nm, more preferably 320 nm to 370 nm, and even more preferably 330 nm to 370 nm. This is because such an ultraviolet absorber can efficiently absorb ultraviolet rays in the UVA region, and can form a hard coat layer having ultraviolet absorbing ability without causing curing inhibition of the hard coat layer by shifting the peak wavelength from the absorption wavelength of 250 nm of the initiator for curing the hard coat layer.

[0112] Among them, it is preferable that the ultraviolet absorber has an absorption wavelength peak of 380 nm or less, since coloring caused by the ultraviolet absorber can be suppressed.

[0113] The absorbance of the ultraviolet absorber can be measured using, for example, an ultraviolet-visible-near infrared spectrophotometer (for example, V-7100 manufactured by JASCO Corporation).

[0114] Examples of the ultraviolet absorber include triazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers such as hydroxybenzophenone-based ultraviolet absorbers, and benzotriazole-based ultraviolet absorbers.

[0115] Among these, from the viewpoint of suppressing deterioration of the base layer due to ultraviolet rays, 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.

[0116] Specific examples of hydroxybenzophenone-based ultraviolet absorbers include those described in JP-A-2019-132930.

[0117] Among the hydroxybenzophenone-based UV absorbers, 2-hydroxybenzophenone-based UV absorbers are preferred, and one or more selected from the group consisting of benzophenone-based UV absorbers having the following general formula (A) are more preferred. These can suppress deterioration of the substrate layer due to UV rays and improve durability.

[0118] [ka]

[0119] (In the general formula (A), X 1 and X 2 are each independently a hydroxyl group, -OR a or a hydrocarbon group having 1 to 15 carbon atoms, Ra represents a hydrocarbon group having 1 to 15 carbon atoms.

[0120] In general formula (A), X 1 , X 2 and R a Examples of the hydrocarbon group having 1 to 15 carbon atoms in the formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a dodecyl group, an allyl group, and a benzyl group. Each of the aliphatic hydrocarbon groups having 3 or more carbon atoms may be linear or branched. The hydrocarbon group preferably has 1 to 12 carbon atoms, and more preferably has 1 to 8 carbon atoms. In terms of facilitating an improvement in transparency, the hydrocarbon group is preferably an aliphatic hydrocarbon group, and of these, a methyl group and an allyl group are preferred.

[0121] X is a material that is easy to improve durability. 1 and X 2 are each independently a hydroxyl group or -OR a It is preferable that:

[0122] The one or more selected from the group consisting of benzophenone-based ultraviolet absorbers having general formula (A) 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.

[0123] Specific examples of benzotriazole-based ultraviolet absorbers include those described in JP-A-2019-132930.

[0124] Among the benzotriazole-based UV absorbers, 2-(2-hydroxyphenyl)benzotriazoles are preferred, and one or more selected from the group consisting of benzotriazole-based UV absorbers having the following general formula (B) are more preferred. These can suppress deterioration of the substrate layer due to UV rays and improve durability.

[0125] [ka]

[0126] (In the general formula (B), Y 1 , Y 2 , and Y 3 are each independently a hydrogen atom, a hydroxyl group, or -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 Y 1 , Y 2 , and Y 3 At least one of the groups is a hydroxyl group, -OR b or a hydrocarbon group having 1 to 15 carbon atoms. 4 represents a hydrogen atom or a halogen atom.

[0127] In general formula (B), Y 1 , Y 2 , and Y 3 , and R b In the formula (I), examples of the hydrocarbon group having 1 to 15 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a dodecyl group. Each of the aliphatic hydrocarbon groups having 3 or more carbon atoms may be linear or branched. The hydrocarbon group preferably has 1 to 12 carbon atoms, and more preferably has 1 to 8 carbon atoms. In terms of facilitating improved transparency, the hydrocarbon group is preferably an aliphatic hydrocarbon group, and is preferably a linear or branched alkyl group, and among these, a methyl group, a t-butyl group, a t-pentyl group, an n-octyl group, or a t-octyl group is preferred.

[0128] In general formula (B), Y4 Examples of the halogen atom in include a chlorine atom, a fluorine atom, and a bromine atom, and among these, a chlorine atom is preferred.

[0129] In general formula (B), Y 1 , and Y 3 is a hydrogen atom, and Y 2 is a hydroxyl group or -OR b and more preferably one or more selected from the group consisting of 2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole and 2-(2,4-dihydroxyphenyl)-2H-benzotriazole. Deterioration of the substrate layer due to ultraviolet rays can be suppressed, and durability can be improved.

[0130] The content of the ultraviolet absorber in the hard coat layer is, for example, preferably 10% by mass or less, more preferably 7% by mass or less, from the viewpoint of suppressing haze caused by mixing the ultraviolet absorber. Also, from the viewpoint of suppressing deterioration of the substrate layer due to ultraviolet rays and improving durability, the content of the ultraviolet absorber in the hard coat layer is preferably 1% by mass or more and 6% by mass or less, more preferably 2% by mass or more and 5% by mass or less.

[0131] (v) antifouling agent The hard coat layer may contain an antifouling agent, which can impart antifouling properties to the laminate.

[0132] The antifouling agent is not particularly limited, and examples thereof 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. One type of antifouling agent may be used alone, or two or more types may be mixed and used.

[0133] A hard coat layer containing a silicone-based antifouling agent or a fluorine-based antifouling agent is less susceptible to fingerprints (less noticeable) and has good wiping properties. Furthermore, when a silicone-based antifouling agent or a fluorine-based antifouling agent is contained, the surface tension of the curable resin composition for a hard coat layer can be reduced during application, resulting in good leveling properties and a good appearance of the resulting hard coat layer.

[0134] Furthermore, the hard coat layer containing the silicone-based antifouling agent has good slipperiness and scratch resistance, and a display device including a laminate having a hard coat layer containing such a silicone-based antifouling agent has good slipperiness when touched with a finger, a pen, or the like, resulting in a good tactile feel.

[0135] The antifouling agent preferably has a reactive functional group in order to improve the durability of the antifouling performance. If the antifouling agent does not have a reactive functional group, regardless of whether the laminate is in the form of a roll or a sheet, when the laminate is stacked, the antifouling agent will be transferred to the surface opposite to the hard coat layer side of the laminate, and when another layer is attached or applied to the surface opposite to the hard coat layer side of the laminate, the other layer may peel off, and further, the other layer may be more likely to peel off when repeatedly bent. In contrast, when the antifouling agent has a reactive functional group, the antifouling performance will be more durable.

[0136] The number of reactive functional groups in the antifouling agent may be at least 1, and preferably at least 2. By using an antifouling agent having two or more reactive functional groups, it is possible to impart excellent scratch resistance to the hard coat layer.

[0137] The antifouling agent preferably has a weight-average molecular weight of not more than 5000. The weight-average molecular weight of the antifouling agent can be measured by gel permeation chromatography (GPC).

[0138] 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 added and suppressing a decrease in the strength of the hard coat layer, it is preferable that the antifouling agent be unevenly distributed on the surface side of the hard coat layer.

[0139] Examples of methods for unevenly distributing the antifouling agent on the surface side of the hard coat layer include a method in which, when forming the hard coat layer, a coating film of a curable resin composition for a hard coat layer is dried and heated before being cured to reduce the viscosity of the resin component contained in the coating film, thereby increasing the fluidity and thereby unevenly distributing the antifouling agent on the surface side of the hard coat layer; and a method in which an antifouling agent with low surface tension is used, and the antifouling agent is floated on the surface of the coating film without applying heat when drying the coating film, and then the coating film is cured, thereby unevenly distributing the antifouling agent on the surface side of the hard coat layer.

[0140] The content of the antifouling agent is preferably, for example, 0.01 to 3.0 parts by mass per 100 parts by mass of the resin component. If the content of the antifouling agent is too low, sufficient antifouling properties may not be imparted to the hard coat layer, whereas if the content of the antifouling agent is too high, the hardness of the hard coat layer may decrease.

[0141] (vi) Other additives The hard coat layer may further contain additives as necessary. The additives are appropriately selected depending on the function to be imparted to the hard coat layer, and are not particularly limited, and examples thereof include inorganic or organic particles for adjusting the refractive index, infrared absorbers, antiglare agents, antifouling agents, antistatic agents, colorants such as blue pigments and purple pigments, leveling agents, surfactants, lubricants, various sensitizers, flame retardants, adhesion promoters, polymerization inhibitors, antioxidants, light stabilizers, and surface modifiers.

[0142] (d) Method for forming a hard coat layer Examples of methods for forming the hard coat layer include a method in which a curable resin composition for a hard coat layer containing the above-mentioned polymerizable compound and the like is applied to a substrate layer and then cured.

[0143] The curable resin composition for a hard coat layer contains a polymerizable compound, and may further contain a polymerization initiator, particles, an ultraviolet absorber, a solvent, an additive, and the like, as necessary.

[0144] The method for applying the curable resin composition for a hard coat layer onto the substrate layer is not particularly limited as long as it allows application to a desired thickness, and examples thereof include common application methods such as gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, spray coating, die coating, screen printing, etc. Furthermore, a transfer method can also be used as a method for forming a coating film of the resin composition for a hard coat layer.

[0145] The coating film of the curable resin composition for the hard coat layer is dried as needed to remove the solvent. Examples of drying methods include vacuum drying, heat drying, and a combination of these drying methods. For example, the coating film can be dried by heating at a temperature of 30°C to 120°C for 10 to 180 seconds.

[0146] The method for curing the coating film of the curable resin composition for the hard coat layer is 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.

[0147] For light irradiation, ultraviolet rays, visible light, electron beams, ionizing radiation, etc. are mainly used. In the case of ultraviolet curing, for example, ultraviolet rays emitted from the light beam of an ultra-high pressure mercury lamp, high pressure mercury lamp, low pressure mercury lamp, carbon arc, xenon arc, metal halide lamp, etc. can be used. The irradiation dose of the energy ray source is, for example, 50 mJ / cm as the cumulative exposure dose at an ultraviolet wavelength of 365 nm. 2 More than 5000mJ / cm 2 It can be set to the following extent.

[0148] When heating is performed, the treatment can be performed at a temperature of, for example, 40° C. or higher and 120° C. or lower. Alternatively, the reaction may be carried out by leaving the mixture at room temperature (25° C.) for 24 hours or more.

[0149] (2) Base material layer The substrate layer in this embodiment is a member that supports the hard coat layer.

[0150] (a) Characteristics of the base layer In this embodiment, the composite elastic modulus of the substrate layer is, for example, preferably 5.7 GPa or more, more preferably 6.5 GPa or more, and even more preferably 7.5 GPa or more. When the composite elastic modulus of the substrate layer is within the above range, the surface hardness of the surface of the laminate on the hard coat film side can be increased, and scratch resistance can be improved.

[0151] Furthermore, according to the method for measuring the composite elastic modulus described below, since the composite elastic modulus of the glass substrate is about 40 GPa, the composite elastic modulus of the substrate layer is, for example, preferably 40 GPa or less, more preferably 30 GPa or less, and even more preferably 20 GPa or less. The composite elastic modulus of the substrate layer is, for example, preferably 5.7 GPa or more and 40 GPa or less, more preferably 6.5 GPa or more and 30 GPa or less, and even more preferably 7.5 GPa or more and 20 GPa or less.

[0152] The method for measuring the composite elastic modulus of the base material layer can be the same as the method for measuring the composite elastic modulus of the bonding layer described above.

[0153] The composite elastic modulus of the substrate layer can be adjusted, for example, by changing the type and composition of the material contained in the substrate layer.

[0154] When the laminate of this embodiment is used in, for example, a display device, the substrate layer preferably has transparency. Specifically, the total light transmittance of the substrate layer is preferably 80% or more, more preferably 85% or more, and even more preferably 88% or more.

[0155] The haze of the substrate layer is preferably, for example, 2% or less, more preferably 1.5% or less, and even more preferably 1% or less.

[0156] (b) Material of the base layer For example, a resin substrate can be used as the substrate layer. The resin constituting the resin substrate preferably satisfies the above-mentioned composite elastic modulus and has transparency. Examples of such resins include polyimide-based resins, polyamide-based resins, polyester-based resins, cellulose-based resins, acrylic-based resins, polycarbonate-based resins, and polyethylene naphthalate-based resins. Examples of polyimide-based resins include polyimide, polyamideimide, polyetherimide, and polyesterimide. Examples of polyester-based resins include polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate (PEN). Examples of cellulose-based resins include triacetyl cellulose (TAC). Examples of acrylic-based resins include polymethyl(meth)acrylate and polyethyl(meth)acrylate. The resin substrate may be a single layer or a multilayer structure such as a coextruded film. Among these, polyimide-based resins are preferred because of their flex resistance, excellent hardness, and transparency.

[0157] The polyimide resin is not particularly limited as long as it satisfies the above-mentioned composite elastic modulus and has transparency, but among the above, polyimide and polyamideimide are preferably used.

[0158] (i) Polyimide The polyimide is obtained by reacting a tetracarboxylic acid component with a diamine component. The polyimide is not particularly limited as long as it satisfies the above-mentioned composite elastic modulus and has transparency, but from the viewpoint of excellent transparency and excellent rigidity, it is preferable that the polyimide has at least one structure selected from the group consisting of structures represented by the following general formula (1) and the following general formula (3).

[0159] [ka]

[0160] In the above general formula (1), R5 is a tetravalent group which is a tetracarboxylic acid residue, R 6 represents at least one divalent group selected from the group consisting of trans-cyclohexanediamine residue, trans-1,4-bismethylenecyclohexanediamine residue, 4,4'-diaminodiphenylsulfone residue, 3,4'-diaminodiphenylsulfone residue, and divalent groups represented by the following general formula (2): n represents the number of repeating units and is 1 or more.

[0161] [ka]

[0162] In the above general formula (2), R 7 and R 8 each independently represents a hydrogen atom, an alkyl group, or a perfluoroalkyl group.

[0163] [ka]

[0164] In the above general formula (3), R 9 represents at least one tetravalent group selected from the group consisting of a cyclohexanetetracarboxylic acid residue, a cyclopentanetetracarboxylic acid residue, a dicyclohexane-3,4,3',4'-tetracarboxylic acid residue, and a 4,4'-(hexafluoroisopropylidene)diphthalic acid residue; R 10 represents a divalent group that is a diamine residue, and n' represents the number of repeating units and is 1 or more.

[0165] The term "tetracarboxylic acid residue" refers to a residue obtained by removing four carboxyl groups from a tetracarboxylic acid, and has the same structure as a residue obtained by removing an acid dianhydride structure from a tetracarboxylic dianhydride. The term "diamine residue" refers to a residue obtained by removing two amino groups from a diamine.

[0166] In the above general formula (1), R 5is a tetracarboxylic acid residue, and can be a residue obtained by removing the acid dianhydride structure from a tetracarboxylic acid dianhydride. Examples of tetracarboxylic acid dianhydrides include those described in International Publication No. 2018 / 070523. R in the above general formula (1) 5 Among these, from the viewpoint of improving transparency and rigidity, it is preferable that the dicarboxylic acid ester contains at least one selected from the group consisting of 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 3,3',4,4'-biphenyltetracarboxylic acid residue, pyromellitic acid residue, 2,3',3,4'-biphenyltetracarboxylic acid residue, 3,3',4,4'-benzophenonetetracarboxylic acid residue, 3,3',4,4'-diphenylsulfonetetracarboxylic acid residue, 4,4'-oxydiphthalic acid residue, cyclohexanetetracarboxylic acid residue, and cyclopentanetetracarboxylic acid residue, and it is further preferable that the dicarboxylic acid ester contains at least one selected from the group consisting of 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 4,4'-oxydiphthalic acid residue, and 3,3',4,4'-diphenylsulfonetetracarboxylic acid residue.

[0167] R 5 In the present invention, the total content of these suitable residues is preferably 50 mol % or more, more preferably 70 mol % or more, and even more preferably 90 mol % or more.

[0168] Also, R 5It is also preferable to use a mixture of a group of tetracarboxylic acid residues (Group A) suitable for improving rigidity, such as at least one selected from the group consisting of 3,3',4,4'-biphenyltetracarboxylic acid residues, 3,3',4,4'-benzophenonetetracarboxylic acid residues, and pyromellitic acid residues, and a group of tetracarboxylic acid residues (Group B) suitable for improving transparency, such as at least one selected from the group consisting of 4,4'-(hexafluoroisopropylidene)diphthalic acid residues, 2,3',3,4'-biphenyltetracarboxylic acid residues, 3,3',4,4'-diphenylsulfonetetracarboxylic acid residues, 4,4'-oxydiphthalic acid residues, cyclohexanetetracarboxylic acid residues, and cyclopentanetetracarboxylic acid residues.

[0169] In this case, the content ratio of the tetracarboxylic acid residue group (Group A) suitable for improving the rigidity to the tetracarboxylic acid residue group (Group B) suitable for improving the transparency is preferably 0.05 to 9 moles, more preferably 0.1 to 5 moles, and even more preferably 0.3 to 4 moles, of the tetracarboxylic acid residue group (Group A) suitable for improving the rigidity per mole of the tetracarboxylic acid residue group (Group B) suitable for improving the transparency.

[0170] R in the above general formula (1) 6 Among them, from the viewpoint of improving transparency and rigidity, it is preferable that the divalent group is at least one selected from the group consisting of a 4,4'-diaminodiphenyl sulfone residue, a 3,4'-diaminodiphenyl sulfone residue, and a divalent group represented by the above general formula (2), and further, it is preferable that the divalent group is at least one selected from the group consisting of a 4,4'-diaminodiphenyl sulfone residue, a 3,4'-diaminodiphenyl sulfone residue, and a divalent group represented by the above general formula (2). 7 and R 8 is preferably at least one divalent group selected from the group consisting of divalent groups represented by the above general formula (2), which is a perfluoroalkyl group.

[0171] R in the above general formula (3)9 Among these, those containing 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 3,3',4,4'-diphenylsulfonetetracarboxylic acid residue, and oxydiphthalic acid residue are preferred, as they improve transparency and rigidity.

[0172] R 9 In the above, these suitable residues are preferably contained in an amount of 50 mol % or more, more preferably 70 mol % or more, and even more preferably 90 mol % or more.

[0173] R in the above general formula (3) 10 is a diamine residue, and can be a residue obtained by removing two amino groups from a diamine. Examples of diamines include those described in WO 2018 / 070523. R in the above general formula (3) 10 Among these, from the viewpoint of improving transparency and rigidity, 2,2'-bis(trifluoromethyl)benzidine residue, bis[4-(4-aminophenoxy)phenyl]sulfone residue, 4,4'-diaminodiphenyl sulfone residue, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residue, bis[4-(3-aminophenoxy)phenyl]sulfone residue, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether residue, 1,4-bis[4-amino-2-(trifluoromethyl)phenoxy]benzene residue, 2,2-bis[4-(4-amino-2-trifluoromethylphenyl) It is preferable that the alkyl group contains at least one divalent group selected from the group consisting of a 2,2'-bis(trifluoromethyl)benzidine residue, a bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residue, a 4,4'-diamino-2-(trifluoromethyl)diphenyl ether residue, a 4,4'-diaminobenzanilide residue, an N,N'-bis(4-aminophenyl)terephthalamide residue, and a 9,9-bis(4-aminophenyl)fluorene residue, and it is further preferable that the alkyl group contains at least one divalent group selected from the group consisting of a 2,2'-bis(trifluoromethyl)benzidine residue, a bis[4-(4-aminophenoxy)phenyl]sulfone residue, and a 4,4'-diaminodiphenyl sulfone residue.

[0174] R 10 In the present invention, the total content of these suitable residues is preferably 50 mol % or more, more preferably 70 mol % or more, and even more preferably 90 mol % or more.

[0175] Also, R 10 and a diamine residue group (Group C) suitable for improving rigidity, such as at least one selected from the group consisting of bis[4-(4-aminophenoxy)phenyl]sulfone residue, 4,4'-diaminobenzanilide residue, N,N'-bis(4-aminophenyl)terephthalamide residue, paraphenylenediamine residue, metaphenylenediamine residue, and 4,4'-diaminodiphenylmethane residue; and a diamine residue group (Group C) suitable for improving rigidity, such as at least one selected from the group consisting of 2,2'-bis(trifluoromethyl)benzidine residue, 4,4'-diaminodiphenylsulfone residue, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residue, bis[4-(3-aminophenoxy)phenyl]sulfone residue, It is also preferred to use a mixture of diamine residues (Group D) suitable for improving transparency, such as at least one selected from the group consisting of 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether residue, 1,4-bis[4-amino-2-(trifluoromethyl)phenoxy]phenyl]sulfone residue, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether residue, 1,4-bis[4-amino-2-(trifluoromethyl)phenoxy]benzene residue, 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane residue, 4,4'-diamino-2-(trifluoromethyl)diphenyl ether residue, and 9,9-bis(4-aminophenyl)fluorene residue.

[0176] In this case, the content ratio of the diamine residue group suitable for improving rigidity (Group C) to the diamine residue group suitable for improving transparency (Group D) is preferably 0.05 to 9 moles, more preferably 0.1 to 5 moles, and even more preferably 0.3 to 4 moles, of the diamine residue group suitable for improving rigidity (Group C) per 1 mole of the diamine residue group suitable for improving transparency (Group D).

[0177] In the structures represented by the general formula (1) and the general formula (3), n and n' each independently represent the number of repeating units and are 1 or more. The number of repeating units n in the polyimide is not particularly limited and may be appropriately selected depending on the structure. The average number of repeating units can be, for example, 10 or more and 2000 or less, and preferably 15 or more and 1000 or less.

[0178] The polyimide may partially contain a polyamide structure, such as a polyamideimide structure containing a tricarboxylic acid residue such as trimellitic anhydride, or a polyamide structure containing a dicarboxylic acid residue such as terephthalic acid.

[0179] In order to improve transparency and surface hardness, R 5 and R 9 a tetravalent group which is a tetracarboxylic acid residue, and R 6 and R 10Preferably, at least one of the divalent groups, which are diamine residues, contains an aromatic ring and at least one selected from the group consisting of (i) a fluorine atom, (ii) an aliphatic ring, and (iii) a structure in which aromatic rings are linked together by a sulfonyl group or an alkylene group optionally substituted with fluorine. When a 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, improving orientation and surface hardness. However, the rigid aromatic ring skeleton tends to extend the absorption wavelength toward longer wavelengths, resulting in reduced transmittance in the visible light region. On the other hand, when a polyimide contains (i) a fluorine atom, the electronic state within the polyimide skeleton is made less susceptible to charge transfer, thereby improving transparency. Furthermore, when a polyimide contains (ii) an aliphatic ring, the conjugation of π electrons within the polyimide skeleton is broken, thereby inhibiting charge transfer within the skeleton, thereby improving transparency. Furthermore, when the polyimide contains (iii) a structure in which aromatic rings are linked together by a sulfonyl group or an alkylene group which may be substituted with fluorine, the conjugation of π electrons in the polyimide skeleton can be broken, thereby inhibiting the movement of charges within the skeleton, thereby improving transparency.

[0180] Among them, R is the most popular because it improves transparency and surface hardness. 5 and R 9 a tetravalent group which is a tetracarboxylic acid residue, and R 6 and R 10 At least one of the divalent groups which are diamine residues preferably contains an aromatic ring and a fluorine atom, and R 6 and R 10 The divalent group which is the diamine residue preferably contains an aromatic ring and a fluorine atom.

[0181] Specific examples of such polyimides include those having a specific structure described in WO 2018 / 070523.

[0182] The polyimide can be synthesized by a known method. Alternatively, commercially available polyimides may be used. Examples of commercially available polyimides include Neoprim (registered trademark) manufactured by Mitsubishi Gas Chemical Company, Inc.

[0183] The weight-average molecular weight of the polyimide is, for example, preferably from 3,000 to 500,000, more preferably from 5,000 to 300,000, and even more preferably from 10,000 to 200,000. If the weight-average molecular weight is too small, sufficient strength may not be obtained, whereas if the weight-average molecular weight is too large, viscosity increases and solubility decreases, making it impossible to obtain a substrate layer with a smooth surface and uniform thickness.

[0184] The weight-average molecular weight of polyimide can be measured by gel permeation chromatography (GPC). Specifically, polyimide is dissolved in N-methylpyrrolidone (NMP) at a concentration of 0.1% by mass, and the developing solvent is a 30 mmol% LiBr-NMP solution with a water content of 500 ppm or less. Measurement is performed using a Tosoh GPC system (HLC-8120, column: SHODEX GPC LF-804) with a sample load of 50 μL, a solvent flow rate of 0.4 mL / min, and a temperature of 37°C. The weight-average molecular weight is determined based on a polystyrene standard sample of the same concentration as the sample.

[0185] (ii) Polyamide-imide The polyamideimide is not particularly limited as long as it satisfies the above-mentioned composite modulus and has transparency. For example, it may have a first block containing structural units derived from a dianhydride and structural units derived from a diamine, and a second block containing structural units derived from an aromatic dicarbonyl compound and structural units derived from an aromatic diamine. In the polyamideimide, the dianhydride may include, for example, biphenyltetracarboxylic dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). The diamine may include bistrifluoromethylbenzidine (TFDB). That is, the polyamideimide has a structure obtained by imidizing a polyamideimide precursor having a first block copolymerized with a monomer containing a dianhydride and a diamine, and a second block copolymerized with a monomer containing an aromatic dicarbonyl compound and an aromatic diamine. The polyamideimide has excellent optical properties as well as thermal and mechanical properties due to the first block containing an imide bond and a second block containing an amide bond. In particular, the use of bistrifluoromethylbenzidine (TFDB) as the diamine forming the first block can improve thermal stability and optical properties, while the use of 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (BPDA) as the dianhydrides forming the first block can improve birefringence and ensure heat resistance.

[0186] The dianhydrides forming the first block include two types of dianhydrides, i.e., 6FDA and BPDA. The first block may contain a polymer bound to TFDB and 6FDA and a polymer bound to TFDB and BPDA, separated by separate repeating units, or may be arranged regularly or completely randomly within the same repeating unit.

[0187] Among the monomers forming the first block, it is preferable that BPDA and 6FDA are contained as dianhydrides in a molar ratio of 1:3 to 3:1, because this not only ensures optical properties but also prevents deterioration of mechanical properties and heat resistance, and allows for excellent birefringence.

[0188] The molar ratio of the first block to the second block is preferably 5:1 to 1:1. If the content of the second block is significantly low, the effect of the second block in improving thermal stability and mechanical properties may not be fully achieved. If the content of the second block is much higher than the content of the first block, although the thermal stability and mechanical properties may be improved, the optical properties may deteriorate, such as a decrease in yellowness and transmittance, and the birefringence properties may also increase. The first block and the second block may be a random copolymer or a block copolymer. The repeating unit of the block is not particularly limited.

[0189] Examples of the aromatic dicarbonyl compound forming the second block include one or more compounds selected from the group consisting of p-terephthaloyl chloride (TPC), terephthalic acid, isophthaloyl dichloride, and 4,4'-benzoyl chloride. Preferably, the aromatic dicarbonyl compound is one or more compounds selected from p-terephthaloyl chloride (TPC) and isophthaloyl dichloride.

[0190] Examples of diamines that form the second block include 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (HFBAPP), bis(4-(4-aminophenoxy)phenyl)sulfone (BAPS), bis(4-(3-aminophenoxy)phenyl)sulfone (BAPSM), 4,4'-diaminodiphenylsulfone (4DDS), 3,3'-diaminodiphenylsulfone (3DDS), 2,2-bis(4-(4-aminophenoxy)phenylpropane (BAPP), 4,4'-diaminodiphenylpropane (6HDA), 1,3-bis(4-aminophenoxy)benzene (134APB), 1, Examples of diamines having one or more flexible groups include 3-bis(3-aminophenoxy)benzene (133APB), 1,4-bis(4-aminophenoxy)biphenyl (BAPB), 4,4'-bis(4-amino-2-trifluoromethylphenoxy)biphenyl (6FAPBP), 3,3-diamino-4,4-dihydroxydiphenyl sulfone (DABS), 2,2-bis(3-amino-4-hydroxyloxyphenyl)propane (BAP), 4,4'-diaminodiphenylmethane (DDM), 4,4'-oxydianiline (4-ODA), and 3,3'-oxydianiline (3-ODA).

[0191] Although aromatic dicarbonyl compounds can easily achieve high thermal stability and mechanical properties, they can also exhibit high birefringence due to the benzene rings in their molecular structure. Therefore, to prevent the birefringence from decreasing due to the second block, it is preferable to use diamines with flexible groups incorporated into their molecular structure. Specifically, the diamine is preferably one or more diamines selected from bis(4-(3-aminophenoxy)phenyl)sulfone (BAPSM), 4,4'-diaminodiphenylsulfone (4DDS), and 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (HFBAPP). In particular, diamines with long flexible groups and meta-positioned substituents, such as BAPSM, can exhibit excellent birefringence.

[0192] A polyamideimide precursor having, in its molecular structure, a first block obtained by copolymerizing a dianhydride containing biphenyltetracarboxylic dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) with a diamine containing bistrifluoromethylbenzidine (TFDB), and a second block obtained by copolymerizing an aromatic dicarbonyl compound with an aromatic diamine, preferably has a weight average molecular weight measured by GPC of, for example, 200,000 or more and 215,000 or less, and a viscosity of, for example, 2400 poise or more and 2600 poise or less.

[0193] Polyamideimide can be obtained by imidizing a polyamideimide precursor. Furthermore, a polyamideimide film can be obtained using the polyamideimide. For a method for imidizing a polyamideimide precursor and a method for producing a polyamideimide film, see, for example, JP-A-2018-506611.

[0194] 4. Glass substrate In this embodiment, the thickness of the glass substrate is 100 μm or less, preferably 90 μm or less, more preferably 80 μm or less, and even more preferably 70 μm or less. Having a glass substrate with a thin thickness within the above range makes it possible to obtain good bending resistance and sufficient hardness. It also makes it possible to suppress curling of the laminate. This is also preferred in terms of reducing the weight of the laminate. On the other hand, the thickness of the glass substrate is, for example, preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more, and particularly preferably 30 μm or more. Having a glass substrate with a thickness within the above range makes it possible to obtain good impact resistance. The thickness of the glass substrate is 10 μm or more and 100 μm or less, preferably 15 μm or more and 90 μm or less, more preferably 20 μm or more and 80 μm or less, and even more preferably 25 μm or more and 75 μm or less.

[0195] Furthermore, the ratio of the thickness of the glass substrate to the total thickness of the laminate is, for example, preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more. When the ratio is within the above range, the thickness of the glass substrate can be made relatively thick, and the texture and tactile feel of glass provided by the glass substrate can be maintained. On the other hand, the ratio of the thickness of the glass substrate to the total thickness of the laminate is, for example, preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. When the ratio is within the above range, the thickness of the hard coat film can be made relatively thick, and impact resistance can be improved. The ratio of the thickness of the glass substrate to the total thickness of the laminate is, for example, preferably 30% or more and 90% or less, more preferably 40% or more and 80% or less, and even more preferably 50% or more and 70% or less.

[0196] The glass constituting the glass substrate is not particularly limited, but chemically strengthened glass is preferable. Chemically strengthened glass is preferable because it has excellent mechanical strength and can be made thinner accordingly. Chemically strengthened glass is typically glass whose mechanical properties have been strengthened by a chemical method by partially exchanging ion species near the surface of the glass, such as replacing sodium with potassium, and has a compressive stress layer on the surface.

[0197] Examples of glasses constituting the chemically strengthened glass substrate include aluminosilicate glass, soda-lime glass, borosilicate glass, lead glass, alkali barium glass, aluminoborosilicate glass, etc. The chemically strengthened glass substrate may also be composed of crystallized glass.

[0198] Examples of commercially available chemically strengthened glass substrates include Gorilla Glass from Corning, Dragontrail from AGC, and chemically strengthened glass from Schott.

[0199] 5. Functional Layer The laminate in this embodiment may further have a functional layer on the side of the hard coat layer opposite to the substrate layer, between the hard coat layer and the substrate layer, between the substrate layer and the bonding layer, between the glass substrate and the bonding layer, or on the side of the glass substrate opposite to the bonding layer.

[0200] The functional layer may be a single layer or may have multiple layers, and may be a layer having a single function or may have multiple layers having different functions.

[0201] Examples of functional layers disposed on the side of the hard coat layer opposite the substrate layer include an anti-reflection layer, an anti-glare layer, and a protective layer. Examples of functional layers disposed between the hard coat layer and the substrate layer include a primer layer, a shatterproof layer, and an impact-absorbing layer. Examples of functional layers disposed between the substrate layer and the bonding layer include a decorative layer, a primer layer, a toning layer, a shatterproof layer, and an impact-absorbing layer. Examples of functional layers disposed between the glass substrate and the bonding layer include an electrode such as ITO, an antenna wiring, and the like. Examples of functional layers disposed on the side of the glass substrate opposite the bonding layer include an adhesive layer, a decorative layer, and an impact-absorbing layer.

[0202] (Anti-reflection layer) The laminate in this embodiment may have an antireflection layer 7 on the side of the hard coat layer 6 opposite to the substrate layer 5, as shown in Fig. 2. The antireflection layer 7 may also be a layer constituting the hard coat film 4, as shown in Fig. 2.

[0203] The antireflection layer may be composed of a single layer or multiple layers.

[0204] As the antireflection layer, a general antireflection layer can be applied, and examples thereof include a single layer film containing a material having a lower refractive index than the hard coat layer, a multilayer film having a high refractive index layer and a low refractive index layer from the hard coat layer side, a multilayer film in which a high refractive index layer and a low refractive index layer are alternately stacked from the hard coat layer side, and a multilayer film having a medium refractive index layer, a high refractive index layer and a low refractive index layer in this order from the hard coat layer side.

[0205] When the antireflection layer is a single layer film, the material contained in the single layer film may be any material having a refractive index lower than that of the hard coat layer, such as magnesium fluoride.

[0206] Furthermore, when the antireflection layer is a multilayer film, the refractive index of the low refractive index layer is, for example, preferably 1.45 or less, more preferably 1.40 or less. By setting the refractive index of the low refractive index layer within the above range, good antireflection properties are achieved. Furthermore, the lower limit of the refractive index of the low refractive index layer is practically 1.10 or more.

[0207] Examples of the low refractive index layer include one containing a hydrolysis polycondensate of a metal alkoxide, one containing a low refractive index resin, one containing low refractive index particles, and one containing a binder resin and low refractive index particles.

[0208] The hydrolysis polycondensate of metal alkoxide can be obtained, for example, by a sol-gel method.

[0209] An example of a resin with a low refractive index is a fluororesin.

[0210] The low refractive index particles are not particularly limited, and for example, inorganic particles such as silica and magnesium fluoride, or organic particles can be used. Among them, particles having voids are preferred from the viewpoint of reducing the reflectance of the anti-reflection layer. Particles having voids have minute voids inside and contain air in the voids, resulting in a low refractive index. Examples of particles having voids include porous particles and hollow particles. Among them, hollow particles are preferred.

[0211] A hollow particle is a particle that has an outer shell layer, and the inside of the particle surrounded by the outer shell layer is hollow and contains air inside the particle.

[0212] The outer shell layer of the hollow particles may be inorganic or organic, for example, made of a metal, a metal oxide, a resin, silica, etc. Among these, hollow silica particles having an outer shell layer made of silica are preferred. When the outer shell layer is made of silica, the silica may be in any state of crystalline, sol, or gel.

[0213] The shape of the hollow particles may be any of spherical, spheroidal, and substantially spherical such as a polyhedral shape that approximates a sphere, chain-like, needle-like, plate-like, flake-like, rod-like, fibrous, etc. Of these, spherical and substantially spherical shapes are preferred, and spheroidal or spherical shapes are more preferred.

[0214] When the low refractive index layer contains a binder resin and low refractive index particles, the low refractive index particles are preferably surface-treated. The surface treatment of the low refractive index particles is preferably a surface treatment using a silane coupling agent. Among these, a surface treatment using a silane coupling agent having a (meth)acryloyl group is preferred. By subjecting the low refractive index particles to a surface treatment, the affinity with the binder resin is improved, the particles are uniformly dispersed, and the particles are less likely to aggregate. This makes it possible to suppress a decrease in the transparency of the low refractive index layer due to particle size increase resulting from aggregation, as well as a decrease in the applicability of the composition for the low refractive index layer and a decrease in the coating strength of the composition for the low refractive index layer.

[0215] Examples of silane coupling agents that are preferably used in the surface treatment of low refractive index particles include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilane, Examples of suitable silanes include dimethylsilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, trifluoropropyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0216] The average particle diameter of the low-refractive-index particles is, for example, preferably 5 nm to 200 nm, more preferably 10 nm to 150 nm. Furthermore, when the low-refractive-index particles are hollow particles, the average particle diameter is, for example, preferably 5 nm to 200 nm, more preferably 30 nm to 150 nm, and even more preferably 50 nm to 110 nm. When the average particle diameter is within the above range, the thickness of the low-refractive-index layer can be easily made uniform. Furthermore, by setting the average particle diameter to 5 nm or more, particle aggregation can be easily suppressed, and in the case of hollow particles, the refractive index of the low-refractive-index layer can be easily reduced. Furthermore, by setting the average particle diameter to 200 nm or less, it is possible to easily suppress a decrease in visibility due to whitening caused by particle diffusion.

[0217] The average particle size of the low refractive index particles and the high refractive index particles described below can be calculated by the following steps (1) to (3). (1) The cross section of the antireflection layer is imaged by TEM or STEM. The acceleration voltage of the TEM or STEM is preferably, for example, 10 kV to 30 kV, and the magnification is preferably, for example, 50,000 to 300,000. (2) Randomly extract 10 particles from the observed image and calculate the particle diameter of each particle. The particle diameter is measured as the distance between two parallel lines that maximizes the distance between the two lines when the cross section of the particle is sandwiched between the two lines. (3) Repeat the same procedure five times on a separate image of the same sample, and use the number average of a total of 50 particles as the average particle size.

[0218] When the low refractive index layer contains a binder resin and low refractive index particles, the content of the low refractive index particles is preferably 20 parts by mass or more and 250 parts by mass or less, more preferably 30 parts by mass or more and 230 parts by mass or less, and even more preferably 40 parts by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the binder resin of the low refractive index layer. If the content of the low refractive index particles is within the above range, a good balance between antireflection properties and scratch resistance can be achieved.

[0219] The proportion of hollow particles relative to the total amount of low refractive index particles contained in the low refractive index layer is preferably 40% by mass or more, more preferably 50% by mass or more. By setting the proportion of hollow particles within this range, the refractive index of the low refractive index layer can be sufficiently reduced, resulting in good antireflection properties.

[0220] The binder resin contained in the low refractive index layer may be a cured product of a curable resin composition. As the curable resin composition, the same ones as those exemplified for the hard coat layer may be used, and a photocurable resin composition is preferred.

[0221] The curable resin composition forming the binder resin preferably contains a fluorine-containing compound such as a fluorine-containing oligomer and / or monomer having a photocurable functional group. The inclusion of a fluorine-containing compound makes it easier to lower the refractive index of the low refractive index layer and also provides the low refractive index layer with antifouling properties and slip properties.

[0222] Furthermore, the thickness of the low refractive index layer is preferably about 1 / 4 of the wavelength range of visible light (around 100 nm), and is therefore, for example, preferably 80 nm or more and 120 nm or less, more preferably 85 nm or more and 110 nm or less, and even more preferably 90 nm or more and 105 nm or less.

[0223] Methods for forming a low refractive index layer include wet methods and dry methods. Wet methods include a method of forming the layer by a sol-gel method using a metal alkoxide or the like, a method of forming the layer by applying a low refractive index resin, and a method of forming the layer by applying a composition for a low refractive index layer containing a binder resin and low refractive index particles. Dry methods include a method of forming the layer by physical vapor deposition or chemical vapor deposition using low refractive index particles. Wet methods are excellent in terms of production efficiency, and among them, a method of forming the layer by applying a composition for a low refractive index layer containing a binder resin and low refractive index particles is preferred.

[0224] The refractive index of the high refractive index layer is preferably, for example, 1.55 or more and 1.85 or less, and more preferably 1.56 or more and 1.70 or less. By making the refractive index of the high refractive index layer a predetermined value or more, the antireflection properties become good. Furthermore, the upper limit of the high refractive index layer is practically 1.85 or less.

[0225] The high refractive index layer may contain, for example, a binder resin and high refractive index particles.

[0226] Examples of high refractive index particles include antimony pentoxide, zinc oxide, titanium oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, yttrium oxide, and zirconium oxide.

[0227] The average particle size of the high refractive index particles is, for example, preferably 5 nm to 200 nm, more preferably 5 nm to 100 nm, and even more preferably 10 nm to 80 nm. By setting the average particle size to 5 nm or more, particle aggregation can be easily suppressed, and by setting the average particle size to 200 nm or less, a decrease in visibility due to whitening caused by particle diffusion can be easily suppressed.

[0228] From the viewpoint of achieving a balance between increasing the refractive index of the coating film and the strength of the coating film, the content of the high refractive index particles is preferably 50 parts by mass or more and 500 parts by mass or less, more preferably 100 parts by mass or more and 450 parts by mass or less, and even more preferably 200 parts by mass or more and 430 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0229] The binder resin contained in the high refractive index layer may be a cured product of a curable resin composition. As the curable resin composition, the same ones as those exemplified for the hard coat layer may be used, and a photocurable resin composition is preferred.

[0230] The thickness of the high refractive index layer is preferably 200 nm or less, more preferably 50 nm or more and 180 nm or less, and even more preferably 90 nm or more and 160 nm or less. By setting the thickness of the high refractive index layer within the above range, low reflectivity can be exhibited over a wide wavelength range within the visible light region (380 nm to 780 nm).

[0231] The high refractive index layer may be formed, for example, by applying a composition for a high refractive index layer containing a binder resin and high refractive index particles.

[0232] The thickness of the antireflection layer can be the same as that of a general antireflection layer, and is appropriately selected depending on the layer structure of the antireflection layer.

[0233] Examples of methods for forming the antireflection layer include coating and vapor deposition, and the method is appropriately selected depending on the material of the antireflection layer.

[0234] 6. Second bonding layer In the laminate of this embodiment, for example, as shown in FIG. 4, a second bonding layer 10 may be disposed on the surface of the glass substrate 2 opposite to the bonding layer 3. The second bonding layer is a layer for bonding the laminate to another member. Examples of the other member include a display panel in a display device, which will be described later. The second bonding layer is usually disposed on the outermost surface of the laminate.

[0235] In this specification, for convenience of explanation, the bonding layer disposed between the glass substrate and the substrate layer will be referred to simply as the "bonding layer," and the bonding layer disposed on the surface of the glass substrate opposite the bonding layer will be referred to as the "second bonding layer."

[0236] One type of impact fracture of a glass substrate is bending fracture. Bending fracture is a phenomenon in which a glass substrate bends due to an impact received by the glass substrate, and the glass substrate breaks when the amount of bending reaches a limit. When an impact is applied instantaneously and locally to the front surface of the glass substrate, the glass substrate is instantaneously and locally deformed, and instantaneous and local tensile stress is generated on the rear surface of the glass substrate. The rear surface of the glass substrate cannot withstand the tensile stress and cracks or breaks.

[0237] The inventors of the present disclosure conducted extensive research into the impact resistance and flex resistance of a laminate having a glass substrate, a bonding layer, and a hard coat film in this order, when the laminate further includes a second bonding layer on the side of the glass substrate opposite the bonding layer. The second bonding layer is typically softer than the glass substrate, substrate layer, and hard coat layer, and is therefore easily deformed by impact. Therefore, when an impact is applied to the laminate, if the second bonding layer deforms to a large extent, instantaneous and localized deformation of the glass substrate is likely to occur. In this case, bending fracture of the glass substrate may occur, potentially reducing impact resistance. Furthermore, they found that when the laminate further includes a second bonding layer on the side of the glass substrate opposite the bonding layer, impact resistance varies significantly depending on the hardness, thickness, etc. of the second bonding layer. Furthermore, it was found that even when the laminate further has a second bonding layer on the side opposite to the bonding layer of the glass substrate, bending fracture of the glass substrate can be suppressed and good bending resistance can be obtained without impairing impact resistance, as long as the ratio of the storage modulus (MPa) of the second bonding layer at 20°C to the thickness (μm) of the second bonding layer is within a predetermined range.

[0238] That is, the ratio of the storage modulus (MPa) of the second bonding layer at 20°C to the thickness (μm) of the second bonding layer is, for example, preferably 0.001 to 0.4, more preferably 0.002 to 0.35, even more preferably 0.003 to 0.3, and particularly preferably 0.004 to 0.2. As described above, the second bonding layer is typically softer than the glass substrate and the substrate layer and hard coat layer of the hard coat film, and is therefore more susceptible to deformation upon impact. The thicker the second bonding layer, the greater the degree of deformation upon impact. Therefore, if the ratio of the storage modulus to the thickness of the second bonding layer is too small, the thickness of the second bonding layer becomes relatively thick, which may result in a decrease in impact resistance. Furthermore, if the ratio of the storage modulus to the thickness of the second bonding layer becomes large, the effect of improving impact resistance becomes saturated. Furthermore, if the ratio of the storage modulus to the thickness of the second bonding layer is too large, the thickness of the second bonding layer will be relatively thin, and the storage modulus of the second bonding layer will be relatively large, which may result in a decrease in bending resistance.

[0239] As described above, when a heat-sensitive adhesive or a curing adhesive, or even when a heat-sealing agent, an ultraviolet-curing adhesive, or a heat-curing adhesive is used for the bonding layer, and particularly when a heat-sealing agent is used, the glass transition temperature and composite modulus of the bonding layer can be easily adjusted within a preferred range, thereby improving impact resistance. Therefore, in such cases, when a second bonding layer is further disposed, it is preferable that the ratio of the storage modulus to the thickness of the second bonding layer be within the above range so as not to impair impact resistance.

[0240] The thickness of the second bonding layer is not particularly limited as long as it satisfies the ratio of the storage modulus to the thickness of the second bonding layer. For example, it is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm, and even more preferably 15 μm to 50 μm. When the thickness of the second bonding layer is equal to or greater than a predetermined value, good adhesion is achieved. In particular, when the thickness of the second bonding layer is 15 μm or greater, good adhesion can be achieved, thereby improving flex resistance, particularly dynamic flex resistance. As described above, the second bonding layer is typically softer than the glass substrate and the substrate layer and hard coat layer of the hard coat film, and therefore is easily deformed by impact. The thicker the second bonding layer, the greater the degree of deformation due to impact. Therefore, when the thickness of the second bonding layer is equal to or less than a predetermined value, the decrease in impact resistance due to the second bonding layer can be suppressed. In particular, when the thickness of the second bonding layer is 50 μm or less, good impact resistance can be achieved.

[0241] The storage modulus of the second bonding layer at 20°C is not particularly limited as long as it satisfies the ratio of storage modulus to thickness of the second bonding layer described above, but is preferably 0.10 MPa to 10 MPa, more preferably 0.10 MPa to 5 MPa, and even more preferably 0.10 MPa to 3 MPa. Having a storage modulus of the second bonding layer equal to or greater than a predetermined value and having a certain degree of hardness allows for good impact resistance to be maintained. Having a storage modulus of the second bonding layer equal to or less than a predetermined value allows for good flex resistance, particularly dynamic flex resistance.

[0242] Here, the storage modulus E' of the second bonding layer at 20°C is a value measured using a dynamic viscoelasticity measuring device (DMA). When measuring the storage modulus E' of the second bonding layer using a dynamic viscoelasticity measuring device (DMA), first, a solution is prepared by dissolving or melting the material of the second bonding layer. The solution is then applied to a substrate, dried, and the film is peeled off from the substrate to obtain a test piece of the second bonding layer. The solvent is appropriately selected depending on the material of the second bonding layer, and examples include ethyl acetate. The substrate can be, for example, a Naflon® sheet (300 mm × 300 mm × 1 mm thick) manufactured by Nichias Corporation. The second bonding layer is then rolled into a cylindrical shape with a diameter of approximately 5 mm and a height of approximately 5 mm. The cylindrical measurement sample is attached between the compression fixture (parallel plates of a diameter of 8 mm) of the dynamic viscoelasticity measuring device. Thereafter, a compressive load is applied, and longitudinal vibration at a frequency of 1 Hz is given, and dynamic viscoelasticity measurement is performed in the range of -50°C to 200°C, and the storage modulus E' of the second bonding layer at each temperature is measured. As a dynamic viscoelasticity measuring device, for example, an RSAIII manufactured by TA Instruments can be used. Specific measurement conditions for the above method are shown below.

[0243] (Measurement conditions for storage modulus E') Measurement sample: φ5mm x height 5mm cylindrical Measurement jig: Compression (parallel plate) Measurement mode: Temperature dependent (Temperature range: -50°C to 200°C, Heating rate: 5°C / min) Frequency: 1Hz

[0244] The storage modulus of the second bonding layer can be adjusted, for example, by the type and composition of the material contained in the second bonding layer.

[0245] Furthermore, as will be described later, when an optically transparent pressure-sensitive adhesive is used for the second bonding layer, the storage modulus of the pressure-sensitive adhesive can be adjusted by a known method for adjusting the elastic modulus, for example, by adjusting the crosslink density, the type of functional group-containing monomer, etc. For example, as the crosslink density increases, the storage modulus tends to increase.

[0246] The glass transition temperature of the second bonding layer is, for example, preferably -50°C or higher and 30°C or lower, more preferably -50°C or higher and 25°C or lower, even more preferably -50°C or higher and 0°C or lower, particularly preferably -45°C or higher and -5°C or lower, and even more preferably -40°C or higher and -5°C or lower. If the glass transition temperature of the second bonding layer is within the above range, it becomes easier to obtain a second bonding layer that satisfies the above-mentioned storage modulus. Furthermore, if the glass transition temperature of the second bonding layer is -40°C or higher, it is possible to improve the low-temperature flexibility. Furthermore, if the glass transition temperature of the second bonding layer is 25°C or lower, it is possible to improve the room-temperature flexibility.

[0247] The glass transition temperature of the second bonding layer can be measured by the same method as that for measuring the glass transition temperature of the bonding layer described above.

[0248] Furthermore, when the thickness (μm) of the second bonding layer is T1, the storage modulus (MPa) of the second bonding layer at 20°C is E'1, and the thickness (μm) of the glass substrate is T2, it is preferable that the following formula (4) is satisfied. T2×E'1 / T1≧0.1 (4) When the above formula (4) is satisfied, for example, even if the thickness of the glass substrate is relatively thin, good impact resistance can be achieved if the second bonding layer has a large storage modulus and a certain degree of hardness. The left side of the above formula (4) is preferably 0.1 or more and 30 or less.

[0249] When the laminate of this embodiment is used in, for example, a display device, the second bonding layer preferably has transparency. Specifically, the total light transmittance of the second bonding layer is preferably 80% or more, more preferably 85% or more, and even more preferably 88% or more.

[0250] The haze of the second bonding layer is preferably, for example, 2% or less, more preferably 1.5% or less, and even more preferably 1% or less.

[0251] The material used for the second bonding layer is preferably a material that satisfies the ratio of storage modulus to thickness of the second bonding layer described above, and an example of such a material is an optically clear adhesive (OCA).

[0252] Examples of optically transparent adhesives include acrylic adhesives, urethane adhesives, silicone adhesives, epoxy adhesives, and vinyl acetate adhesives. Among them, acrylic adhesives are preferred from the viewpoints of flex resistance, adhesion, and transparency. Commercially available optically transparent adhesives can also be used.

[0253] Examples of methods for disposing the second bonding layer include a method of applying an adhesive onto a glass substrate, and a method of using a film-like second bonding layer and bonding the second bonding layer onto the glass substrate.

[0254] 7. Second substrate layer and third bonding layer In the laminate in this embodiment, for example, as shown in FIG. 3, a third bonding layer 8 and a second substrate layer 9 may be arranged on the side of the glass substrate 2 opposite to the bonding layer 3, from the glass substrate 2 side.

[0255] For ease of explanation, in this specification, the bonding layer disposed between the glass substrate and the substrate layer will be simply referred to as the "bonding layer," and the bonding layer disposed between the glass substrate and the second substrate layer will be referred to as the "third bonding layer." The third bonding layer is not included in the second bonding layer.

[0256] The third bonding layer and the second substrate layer are disposed on the surface of the glass substrate opposite the bonding layer, from the glass substrate side, thereby improving impact resistance while maintaining good bending resistance. The reason for this is presumed to be as follows.

[0257] The inventors of the present disclosure have conducted extensive research into cracking and breakage of glass substrates due to impact, and have newly discovered that when an impact is applied instantaneously and locally to the surface of a glass substrate, the glass substrate is instantaneously and locally deformed, and tensile stress is instantaneously and locally generated on the rear surface of the glass substrate, and the rear surface of the glass substrate cannot withstand the tensile stress, resulting in cracking and breakage.

[0258] When a second substrate layer is disposed on the surface (rear surface) of the glass substrate opposite to the bonding layer via a third bonding layer, instantaneous and local deformation of the glass substrate due to impact from the surface on the hard coat film side of the laminate can be suppressed, and instantaneous and local tensile stress can be suppressed from occurring on the rear surface of the glass substrate, thereby improving impact resistance.

[0259] (1) Second base layer The second substrate layer in this embodiment is disposed on the surface of the glass substrate opposite the bonding layer via a third bonding layer, and is a layer for suppressing instantaneous and local deformation of the glass substrate due to impact. When the laminate in this embodiment is disposed on the viewer side of a display panel of a display device, for example, the laminate is disposed so that the surface on the second substrate layer side faces the display panel. Furthermore, when the laminate in this embodiment is disposed on the surface of a resin molded product, for example, the laminate is disposed so that the surface on the second substrate layer side faces the resin molded product.

[0260] In this embodiment, the composite elastic modulus of the second substrate layer is, for example, preferably 7.0 GPa or more, more preferably 7.3 GPa or more, and even more preferably 7.5 GPa or more. When the composite elastic modulus of the second substrate layer is within the above range, instantaneous and local deformation of the glass substrate due to impact can be suppressed, and cracking of the glass substrate due to impact can be suppressed, thereby improving impact resistance. On the other hand, the composite elastic modulus of the second substrate layer is, for example, 100 GPa or less, or may be 90 GPa or less, or may be 80 GPa or less. The composite elastic modulus of the second substrate layer is, for example, preferably 7.0 GPa or more and 100 GPa or less, more preferably 7.3 GPa or more and 90 GPa or less, and even more preferably 7.5 GPa or more and 80 GPa or less.

[0261] The method for measuring the composite elastic modulus of the second base material layer can be the same as the method for measuring the composite elastic modulus of the bonding layer described above.

[0262] The composite elastic modulus of the second base material layer can be adjusted, for example, by the type and composition of the material contained in the second base material layer.

[0263] When the laminate of this embodiment is used in, for example, a display device, the second base layer preferably has transparency. Specifically, the total light transmittance of the second base layer is preferably 80% or more, more preferably 85% or more, and even more preferably 88% or more.

[0264] The haze of the second base layer is, for example, preferably 2% or less, more preferably 1.5% or less, and even more preferably 1% or less.

[0265] The thickness of the second substrate layer is not particularly limited as long as it is a thickness that can suppress instantaneous and local deformation of the glass substrate due to impact, and is, for example, preferably 25 μm or more, more preferably 27 μm or more, and even more preferably 29 μm or more. The thicker the second substrate layer, the more improved the impact resistance. On the other hand, the thickness of the second substrate layer is preferably equal to or less than the thickness of the glass substrate, and for example, is preferably 100 μm or less, more preferably 90 μm or less, and even more preferably 80 μm or less. If the thickness of the second substrate layer is too thick, the flex resistance may decrease. If the thickness of the second substrate layer is within the above range, the impact resistance can be improved while maintaining the flex resistance. The thickness of the second substrate layer is, for example, preferably 25 μm to 100 μm, more preferably 27 μm to 90 μm, and even more preferably 29 μm to 80 μm.

[0266] The second substrate layer is not particularly limited as long as it satisfies the above-mentioned composite elastic modulus, and examples thereof include a glass layer and a resin layer containing a polyimide resin or an aramid resin. Among these, the second substrate layer is preferably a glass layer. A glass layer usually has a higher composite elastic modulus than a resin layer, and therefore can improve impact resistance.

[0267] When the second substrate layer is a glass layer, the glass constituting the glass layer can be the same as the glass constituting the above-mentioned glass substrate.

[0268] When the second base layer is a resin layer, examples of the resin contained in the resin layer include polyimide resins and aramid resins.

[0269] The polyimide resin is not particularly limited as long as it satisfies the above-mentioned composite elastic modulus, and examples thereof include polyimide, polyamideimide, etc. When the above-mentioned substrate layer is a resin substrate, the polyimide and polyamideimide may be the same as the polyimide and polyamideimide contained in the resin substrate.

[0270] The aramid resin is not particularly limited as long as it satisfies the above-mentioned composite elastic modulus.

[0271] The resin layer may further contain additives as needed, such as ultraviolet absorbers, light stabilizers, antioxidants, inorganic particles, silica fillers for facilitating winding, surfactants for improving film-forming properties and defoaming properties, and adhesion improvers.

[0272] As a method for arranging the second base material layer, for example, a method of bonding the second base material layer to the surface of the glass base material opposite to the bonding layer via a third bonding layer can be mentioned.

[0273] (2) Third bonding layer The third bonding layer in this embodiment is a layer disposed between the glass substrate and the second substrate layer, and serves to bond the glass substrate and the second substrate layer together.

[0274] The thickness of the third bonding layer is preferably thinner than the thickness of the glass substrate. For example, it is preferably less than 100 μm, more preferably 50 μm or less, and even more preferably 25 μm or less. If the thickness of the third bonding layer is too thick, bending resistance may be impaired. Furthermore, the third bonding layer is typically softer than the glass substrate and the second substrate layer and is therefore more susceptible to deformation upon impact. The thicker the third bonding layer, the greater the degree of deformation upon impact tends to be. Therefore, if the third bonding layer is too thick, when an impact is applied to the laminate, the degree of deformation of the third bonding layer increases, which is thought to result in instantaneous and localized deformation of the glass substrate. In this case, the glass substrate may be more susceptible to cracking or breakage, resulting in reduced impact resistance. On the other hand, the thickness of the third bonding layer is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 5 μm or more. If the thickness of the third bonding layer is too thin, adhesion may be weakened and the layer may peel off. The thickness of the third bonding layer is, for example, preferably 0.5 μm or more and less than 100 μm, more preferably 1 μm or more and 50 μm or less, and even more preferably 5 μm or more and 25 μm or less.

[0275] The composite modulus of the third bonding layer is, for example, preferably 1.0 MPa or more, more preferably 2.0 MPa or more, and even more preferably 3.0 MPa or more. Having a composite modulus of the third bonding layer within the above range and having a certain degree of hardness can improve impact resistance. Furthermore, as described above, the third bonding layer is typically softer than the glass substrate and the second substrate layer and is therefore more susceptible to deformation upon impact. The smaller the composite modulus of the third bonding layer, the greater the degree of deformation upon impact. Therefore, if the composite modulus of the third bonding layer is too small, when an impact is applied to the laminate, the greater the degree of deformation of the third bonding layer, which is likely to cause instantaneous and localized deformation of the glass substrate. In this case, the glass substrate may be more susceptible to cracking or breakage, resulting in reduced impact resistance. Meanwhile, the composite modulus of the third bonding layer is, for example, preferably 1.9 GPa or less, more preferably 1.8 GPa or less, and even more preferably 1.5 GPa or less. If the composite elastic modulus of the third bonding layer is within the above range, it is softer than the glass substrate and the second substrate layer, and therefore can absorb impacts and improve impact resistance. If the composite elastic modulus of the third bonding layer is too high, bending resistance may be impaired. The composite elastic modulus of the third bonding layer is, for example, preferably 1.0 MPa or more and 1.9 GPa or less, more preferably 2.0 MPa or more and 1.8 GPa or less, and even more preferably 3.0 MPa or more and 1.5 GPa or less.

[0276] The method for measuring the composite elastic modulus of the third bonding layer can be the same as the method for measuring the composite elastic modulus of the bonding layer described above.

[0277] The composite elastic modulus of the third bonding layer can be adjusted, for example, by the type of material contained in the bonding layer.

[0278] Furthermore, as will be described later, when an optically transparent pressure-sensitive adhesive is used for the third bonding layer, the composite elastic modulus of the pressure-sensitive adhesive can be adjusted by a known method for adjusting the elastic modulus, for example, by adjusting the crosslink density, the type of functional group-containing monomer, etc. For example, the composite elastic modulus tends to increase as the crosslink density increases.

[0279] When the laminate of this embodiment is used in, for example, a display device, the third bonding layer preferably has transparency. Specifically, the total light transmittance of the third bonding layer is preferably 80% or more, more preferably 85% or more, and even more preferably 88% or more.

[0280] The haze of the third bonding layer is preferably, for example, 2% or less, more preferably 1.5% or less, and even more preferably 1% or less.

[0281] The material used for the third bonding layer is not particularly limited as long as it is a material that can bond the glass substrate and the second substrate layer, but it is preferable that the material satisfy the above-mentioned composite elastic modulus and transparency, and examples thereof include an optically clear adhesive (OCA), a curable adhesive, etc.

[0282] Examples of optically transparent pressure-sensitive adhesives include acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, silicone pressure-sensitive adhesives, epoxy pressure-sensitive adhesives, vinyl acetate pressure-sensitive adhesives, etc. Among these, acrylic pressure-sensitive adhesives are preferred from the viewpoints of flex resistance, adhesion, and transparency.

[0283] In particular, it is preferable that the optically transparent pressure-sensitive adhesive satisfy the above-mentioned composite elastic modulus. Commercially available products can be used as such optically transparent pressure-sensitive adhesives. Specific examples include "8146-2" manufactured by 3M, and "MO-3018C," "F619," and "N632" manufactured by Lintec Corporation.

[0284] The curing adhesive may be the same as the curing adhesive used for the bonding layer described above.

[0285] 8. Protective film In the laminate of this embodiment, a protective film may be disposed on the side of the hard coat film opposite the bonding layer. The protective film can protect the laminate and increase impact resistance.

[0286] In this embodiment, as described above, by setting the ratio (A+B) / C of the thickness A of the hard coat layer, the thickness B of the base layer, and the thickness C of the bonding layer to a predetermined value or more, the surface hardness of the surface of the laminate on the hard coat film side can be increased and scratch resistance can be improved. When a protective film is disposed, scratches and dents may occur in the protective film itself, but the hard coat film has high surface hardness and therefore good scratch resistance.

[0287] On the other hand, if the thickness ratio (A+B) / C does not reach a predetermined value, scratches or dents may occur in the hard coat film even when a protective film is disposed.

[0288] 9. Properties of laminates The laminate in this embodiment preferably has transparency when used in a display device. Specifically, the total light transmittance of the laminate in this embodiment is, for example, preferably 80% or more, more preferably 85% or more, and even more preferably 88% or more. Such a high total light transmittance allows the laminate to have good transparency.

[0289] Here, the total light transmittance of the laminate can be measured in accordance with JIS K7361-1, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

[0290] The haze of the laminate in this embodiment is, for example, preferably 2% or less, more preferably 1.5% or less, and even more preferably 1% or less. Such a low haze allows the laminate to have good transparency.

[0291] The haze of the laminate can be measured in accordance with JIS K-7136, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

[0292] The laminate in this embodiment preferably has flex resistance. Specifically, when the laminate in this embodiment is subjected to a dynamic flex test described below, it is preferable that the laminate does not crack, break, or peel.

[0293] In the dynamic bending test, the laminate may be folded so that the glass substrate is on the outside, or the laminate may be folded so that the glass substrate is on the inside, but in either case, it is preferable that the laminate does not crack, break, or peel.

[0294] The dynamic bending test is performed as follows. As shown in FIG. 5(a), in the dynamic bending test, first, a short side 1C of a laminate 1 measuring 20 mm × 100 mm and a short side 1D opposite the short side 1C are fixed by parallel fixing portions 21. Also, as shown in FIG. 5(a), the fixing portions 21 are slidable horizontally. Next, as shown in FIG. 5(b), the fixing portions 21 are moved closer to each other to deform the laminate 1 so as to fold it. Furthermore, as shown in FIG. 5(c), the fixing portions 21 are moved to a position where the distance d between the two opposing short side portions 1C and 1D fixed by the fixing portions 21 of the laminate 1 becomes a predetermined value. Then, the fixing portions 21 are moved in the opposite direction to eliminate the deformation of the laminate 1. By moving the fixing portions 21 as shown in FIGS. 5(a) to 5(c), the laminate 1 can be folded 180°. Furthermore, by conducting a dynamic bending test so that the bent portion 1E of the laminate 1 does not protrude from the lower end of the fixed portion 21 and controlling the distance d when the fixed portion 21 is closest, the distance d between the two opposing short side portions 1C, 1D of the laminate 1 can be set to a predetermined value. For example, if the distance d between the two opposing short side portions 1C, 1D is 10 mm, the outer diameter of the bent portion 1E is considered to be 10 mm.

[0295] It is preferable that the laminate does not crack, break, or peel when a test in which the laminate 1 is folded 180° so that the distance d between the opposing short side portions 1C and 1D of the laminate 1 is 10 mm is repeated 200,000 times, and it is particularly preferable that the laminate does not crack, break, or peel when a test in which the laminate 1 is folded 180° so that the distance d between the opposing short side portions 1C and 1D of the laminate 1 is 8 mm is repeated 200,000 times.

[0296] Here, in the dynamic bending test, "cracking" refers to the phenomenon in which a crack occurs in the laminate, "fracture" refers to the phenomenon in which the laminate completely splits into two pieces, and "peeling" refers to the phenomenon in which any layer constituting the laminate peels off or lifts off.

[0297] Furthermore, in the laminate of this embodiment, when the laminate is subjected to the static bending test described below, the opening angle θ of the laminate after the static bending test is preferably 100° or more, and more preferably 130° or more.

[0298] The static bending test is performed as follows. First, as shown in FIG. 6(a), a short side 1C of a laminate 1 measuring 20 mm × 100 mm and a short side 1D opposite to short side 1C are fixed with fixing parts 22 arranged parallel to each other so that the distance d between short side 1C and short side 1D is 10 mm. Then, a static bending test is performed in which the laminate 1 is left in a folded state at 23°C for 240 hours. After the static bending test, as shown in FIG. 6(b), the fixing parts 22 are removed from short side 1D to unfold the laminate 1, and the opening angle θ, which is the angle at which the laminate 1 naturally opens after 30 minutes at room temperature, is measured. The larger the opening angle θ, the better the recovery property, and the maximum opening angle is 180°.

[0299] In the static bending test, the laminate may be folded so that the glass substrate is on the inside, or the laminate may be folded so that the glass substrate is on the outside. In either case, the opening angle θ is preferably 100° or more, and more preferably 130° or more.

[0300] In the laminate of this embodiment, when the laminate is subjected to a puncture test described below, the puncture breaking strength is, for example, preferably 16 N or more, more preferably 19 N or more, and even more preferably 25 N or more. When the puncture breaking strength is in the above range, the impact resistance is good.

[0301] The puncture test is performed as follows. First, a 100 μm thick PET film (Toyobo Co., Ltd., "A4160 (current product number)" ("A4100 (old product number)"), composite modulus of elasticity 6.9 GPa) is bonded to the glass substrate side of the laminate via a 50 μm thick optically clear adhesive film (OCA) (3M Co., Ltd., "8146-2", composite modulus of elasticity 9.6 MPa) to prepare a test laminate. Next, the test laminate is subjected to a puncture test from the hard coat film side of the test laminate to the PET film side using an A&D Tensilon universal testing machine (RTC-1310A) under the conditions of a needle tip curvature radius of 0.5 mm and a puncture speed of 50 mm / min. At this time, the stroke and load on the surface of the test laminate are set to zero for measurement. The maximum stress at which the glass substrate breaks is taken as the puncture fracture force.

[0302] 10. Applications of laminates The use of the laminate in this embodiment is not particularly limited, and for example, the laminate can be used as a component arranged on the viewer's side of a display panel in a display device, such as a smartphone, a tablet terminal, a wearable terminal, a personal computer, a television, a digital signage, a public information display (PID), or an in-vehicle display.

[0303] The laminate in this embodiment has good flex resistance and impact resistance, and therefore can be suitably used as a component that can accommodate curved surfaces. The laminate in this disclosure can be preferably used for flexible displays such as foldable displays, rollable displays, bendable displays, and slidable displays, and is more preferably used for foldable displays. In addition, the laminate in this embodiment can be used as a surface material for resin molded products having curved surfaces, and can impart design and aesthetic appeal.

[0304] When the laminate in this embodiment is placed on the surface of a display device, a resin molded product, or the like, it is placed so that the surface on the glass substrate side is on the inside and the surface on the hard coat film side is on the outside.

[0305] The method for disposing the laminate in this embodiment on the surface of a display device, a resin molded product, etc. is not particularly limited, and examples thereof include a method using an adhesive layer, etc. As the adhesive layer, a known adhesive layer used for adhering laminates can be used.

[0306] II. Second embodiment The inventors of the present disclosure have conducted extensive research on laminates having glass substrates and have found that by disposing a resin layer on the surface of a thin glass substrate and further increasing the thickness of the resin layer, it is possible to suppress cracking of the glass substrate and improve its impact resistance. However, it has been found that when a resin composition is applied to the surface of a glass substrate to form a relatively thick resin layer, the difference in shrinkage between the glass substrate and the resin layer becomes significant during heating or curing after application of the resin composition, which can result in curling. The inventors of the present disclosure have conducted further research and found that by forming a resin layer into a film in advance and then bonding the resin film to the surface of the thin glass substrate via a bonding layer, it is possible to suppress curling and further improve impact resistance.

[0307] In order to bond the laminate to another member, a second bonding layer can be disposed on the opposite side of the glass substrate from the bonding layer. The inventors of the present disclosure further studied a laminate having a second bonding layer, a glass substrate, a bonding layer, and a resin film in this order. They found that the impact resistance of such a laminate may be reduced depending on the type of the second bonding layer.

[0308] The present embodiment has been made in view of the above circumstances, and aims to provide a laminate that can achieve both flex resistance and impact resistance.

[0309] A second embodiment of the laminate according to the present disclosure is a laminate having, in this order, a hard coat layer, a base layer, a bonding layer, a glass base material, and a second bonding layer, wherein the bonding layer bonds the glass base material and the base layer, the second bonding layer bonds the laminate to another member, the glass base material having a thickness of 10 μm or more and 100 μm or less, and satisfying the following formula (1): 0.001≦{(E1×D1 2 +E2×D2 2 +E3×D3 2 )×E4×D4 2 ×E5×1000} / D5≦3.0 (1) (In the above formula (1), E1 represents the composite elastic modulus (GPa) of the hard coat layer, D1 represents the thickness (mm) of the hard coat layer, E2 represents the composite elastic modulus (GPa) of the base layer, D2 represents the thickness (mm) of the base layer, E3 represents the composite elastic modulus (GPa) of the bonding layer, D3 represents the thickness (mm) of the bonding layer, E4 represents the composite elastic modulus (GPa) of the glass substrate, D4 ​​represents the thickness (mm) of the glass substrate, E5 represents the storage modulus (GPa) of the second bonding layer, and D5 represents the thickness (mm) of the second bonding layer.)

[0310] 7 is a schematic cross-sectional view showing an example of a laminate according to this embodiment. As shown in FIG. 7, the laminate 1 includes, in this order, a hard coat layer 6, a base layer 5, a bonding layer 3, a glass substrate 2, and a second bonding layer 10. The glass substrate 2 has a predetermined thickness. The composite elastic modulus E1 and thickness D1 of the hard coat layer 6, the composite elastic modulus E2 and thickness D2 of the base layer 5, the composite elastic modulus E3 and thickness D3 of the bonding layer 3, the composite elastic modulus E4 and thickness D4 of the glass substrate 2, and the storage modulus E5 and thickness D5 of the second bonding layer 10 all satisfy the above formula (1).

[0311] In the laminate of this embodiment, the glass substrate has a thickness of a predetermined value or less and is therefore thin, thereby improving flex resistance. On the other hand, since the glass substrate has a thickness of a predetermined value or less and is therefore thin, there is a concern that it may be easily broken and have low impact resistance. In contrast, in this embodiment, the hard coat layer, substrate layer, bonding layer, glass substrate, and second bonding layer are arranged in this order, and the elastic modulus and thickness of each layer satisfy the above formula (1), thereby improving impact resistance while maintaining good flex resistance. The reason for this is presumed to be as follows.

[0312] Here, impact fracture of glass can be broadly divided into two types. The first is bending fracture. The second is Hertzian fracture. Hertzian fracture is also called concentrated stress fracture. Bending fracture occurs on the surface of the glass opposite to the impact surface. On the other hand, Hertzian fracture occurs on the impact surface of the glass.

[0313] The inventors of the present disclosure conducted extensive research into the impact resistance and flex resistance of a laminate having, in this order, a hard coat layer, a substrate layer, a bonding layer, a glass substrate, and a second bonding layer. The second bonding layer is typically softer than the glass substrate, the substrate layer, and the hard coat layer, and is therefore more susceptible to deformation upon impact. Therefore, when an impact is applied to the laminate, if the second bonding layer deforms to a large extent, instantaneous and localized deformation is likely to occur in the glass substrate. In this case, there is a concern that the glass substrate may be more susceptible to bending fracture. On the other hand, if the thickness of the second bonding layer is relatively thin, bending fracture of the glass substrate may be suppressed. Furthermore, if the second bonding layer is relatively hard, bending fracture of the glass substrate may also be suppressed. However, even if bending fracture of the glass substrate can be suppressed by making the second bonding layer relatively thin or by making the second bonding layer relatively hard, Hertzian fracture of the glass substrate cannot be suppressed. To suppress Hertzian fracture of the glass substrate, it is preferable to relatively increase the thickness of the hard coat layer, the substrate layer, and the bonding layer, or to relatively increase the hardness of the hard coat layer, the substrate layer, and the bonding layer. Furthermore, among the thicknesses of each layer, the thickness of the glass substrate has the greatest effect on impact fracture of the glass substrate. However, even if Hertzian fracture of the glass substrate can be suppressed by relatively increasing the thickness of the hard coat layer, the substrate layer, and the bonding layer, or by relatively increasing the hardness of the hard coat layer, the substrate layer, and the bonding layer, there is a risk of a decrease in flex resistance. Furthermore, even if impact fracture of the glass substrate can be suppressed by increasing the thickness of the glass substrate, there is a risk of a decrease in flex resistance. Based on the influence of the thickness and hardness of each layer on impact resistance and flex resistance and the experimental results described in the Examples and Comparative Examples below, the above formula (1) was derived, which shows the correlation between the thickness and elastic modulus of each layer and impact resistance and flex resistance.

[0314] If the value of the middle part of the above formula (1) is too small, the thickness of the second bonding layer becomes relatively large, or the storage modulus of the second bonding layer becomes relatively low. This may result in the glass substrate being more susceptible to bending fracture and reduced impact resistance. On the other hand, if the value of the middle part of the above formula (1) is too large, the thicknesses of the glass substrate, hard coat layer, substrate layer, and bonding layer may become relatively large, or the composite modulus of the hard coat layer, substrate layer, and bonding layer may become relatively high. This may result in reduced flex resistance. Therefore, in this embodiment, by ensuring that the modulus and thickness of each layer satisfy the above formula (1), it is possible to improve impact resistance while maintaining good flex resistance.

[0315] Thus, in this embodiment, it is possible to improve impact resistance while maintaining good bending resistance. Moreover, even if the glass substrate in the laminate is broken, the risk of injury to the human body can be reduced, making it possible to provide a highly safe laminate. Therefore, the laminate in this embodiment can be bent and used for a wide variety of applications. The laminate in this embodiment can be used, for example, in a wide variety of display devices, and specifically, can be used as a member for a foldable display.

[0316] The laminate in this embodiment satisfies the following formula (1). 0.001≦{(E1×D1 2 +E2×D2 2 +E3×D3 2 )×E4×D4 2 ×E5×1000} / D5≦3.0 (1) (In the above formula (1), E1 represents the composite elastic modulus (GPa) of the hard coat layer, D1 represents the thickness (mm) of the hard coat layer, E2 represents the composite elastic modulus (GPa) of the base layer, D2 represents the thickness (mm) of the base layer, E3 represents the composite elastic modulus (GPa) of the bonding layer, D3 represents the thickness (mm) of the bonding layer, E4 represents the composite elastic modulus (GPa) of the glass substrate, D4 ​​represents the thickness (mm) of the glass substrate, E5 represents the storage modulus (GPa) of the second bonding layer, and D5 represents the thickness (mm) of the second bonding layer.)

[0317] The value of the middle part of the above formula (1) is 0.001 or more and 3 or less, preferably 0.0015 or more and 1.5 or less, more preferably 0.003 or more and 1 or less, even more preferably 0.005 or more and 0.7 or less, and particularly preferably 0.01 or more and 0.4 or less. As described above, if the value of the middle part of the above formula (1) is too small, the thickness of the second bonding layer becomes relatively large, or the storage modulus of the second bonding layer becomes relatively low. This may result in the glass substrate being more susceptible to bending fracture and reduced impact resistance. On the other hand, if the value of the middle part of the above formula (1) is too large, the thicknesses of the glass substrate, hard coat layer, substrate layer, and bonding layer become relatively large, or the composite modulus of the hard coat layer, substrate layer, and bonding layer become relatively high. This may result in reduced flex resistance.

[0318] Furthermore, as described above, even if bending fracture of the glass substrate can be suppressed by relatively thinning the thickness of the second bonding layer or by relatively increasing the hardness of the second bonding layer, Hertzian fracture of the glass substrate cannot be suppressed. Therefore, when the value of the middle part of the above formula (1) exceeds a certain value, the effect of suppressing bending fracture of the glass substrate becomes saturated. Therefore, it is preferable that the value of the middle part of the above formula (1) is 0.4 or less.

[0319] The thickness of the hard coat layer, the thickness of the substrate layer, the thickness of the bonding layer, the thickness of the glass substrate, and the thickness of the second bonding layer are the same as the thickness of each layer in the laminate of the first embodiment above.

[0320] The composite elastic modulus of the hard coat layer is, for example, preferably 4 GPa or more and 10 GPa or less, more preferably 5 GPa or more and 9 GPa or less, and even more preferably 6 GPa or more and 8 GPa or less. If the composite elastic modulus of the hard coat layer is too small, sufficient scratch resistance may not be obtained. On the other hand, if the composite elastic modulus of the hard coat layer is too large, the hardness may be too high, making it difficult to bend, and the bending resistance, especially the dynamic bending resistance, may be reduced.

[0321] The method for measuring the composite elastic modulus of the hard coat layer is the same as the method for measuring the composite elastic modulus of the bonding layer in the first embodiment.

[0322] The composite elastic modulus of the hard coat layer can be adjusted, for example, by the type and composition of the material contained in the hard coat layer.

[0323] The composite elastic modulus of the substrate layer is the same as the composite elastic modulus of the substrate layer in the first embodiment.

[0324] The composite elastic modulus of the bonding layer is the same as the composite elastic modulus of the bonding layer in the first embodiment.

[0325] The composite elastic modulus of the glass substrate is, for example, preferably 40 GPa or more and 100 GPa or less, more preferably 50 GPa or more and 90 GPa or less, and even more preferably 60 GPa or more and 80 GPa or less.

[0326] The storage modulus of the second bonding layer is the storage modulus at 20° C. The storage modulus of the second bonding layer is the same as the storage modulus of the second bonding layer in the first embodiment.

[0327] The hard coat layer, substrate layer, bonding layer, glass substrate, and second bonding layer in this embodiment are the same as the respective layers in the first embodiment.

[0328] The laminate of this embodiment may further include a functional layer on the side of the hard coat layer opposite the substrate layer, between the hard coat layer and the substrate layer, between the substrate layer and the bonding layer, between the glass substrate and the bonding layer, or between the glass substrate and the second bonding layer. The functional layer is the same as the functional layer in the first embodiment.

[0329] In the laminate of this embodiment, a protective film may be disposed on the side of the hard coat layer opposite to the substrate layer, which is the same as the protective film in the first embodiment.

[0330] The properties and uses of the laminate of this embodiment are similar to those of the laminate of the first embodiment.

[0331] III. Third embodiment Similar to the second embodiment, the object of this embodiment is to provide a laminate that can achieve both flex resistance and impact resistance.

[0332] A third embodiment of the laminate in the present disclosure is a laminate having, in this order, a base layer, a bonding layer, a glass base material, and a second bonding layer, wherein the bonding layer bonds the glass base material and the base layer, the second bonding layer bonds the laminate to another member, the glass base material having a thickness of 10 μm or more and 100 μm or less, and satisfying the following formula (2): 0.001≦{(E2×D2 2 +E3×D3 2 )×E4×D4 2 ×E5×1000} / D5≦3.0 (2) (In the above formula (2), E2 represents the composite elastic modulus (GPa) of the base layer, D2 represents the thickness (mm) of the base layer, E3 represents the composite elastic modulus (GPa) of the bonding layer, D3 represents the thickness (mm) of the bonding layer, E4 represents the composite elastic modulus (GPa) of the glass base, D4 ​​represents the thickness (mm) of the glass base, E5 represents the storage modulus (GPa) of the second bonding layer, and D5 represents the thickness (mm) of the second bonding layer.)

[0333] Fig. 8 is a schematic cross-sectional view showing an example of a laminate in this embodiment. As shown in Fig. 7, the laminate 1 has a base layer 5, a bonding layer 3, a glass substrate 2, and a second bonding layer 10, in this order. The glass substrate 2 has a predetermined thickness. The composite elastic modulus E2 and thickness D2 of the base layer 5, the composite elastic modulus E3 and thickness D3 of the bonding layer 3, the composite elastic modulus E4 and thickness D4 of the glass substrate 2, and the storage elastic modulus E5 and thickness D5 of the second bonding layer 10 satisfy the above formula (2).

[0334] In the laminate of this embodiment, the glass substrate has a thickness of a predetermined value or less and is therefore thin, thereby improving flex resistance. On the other hand, since the glass substrate has a thickness of a predetermined value or less and is therefore thin, there is a concern that it may be easily broken and have low impact resistance. In contrast, in this embodiment, the substrate layer, the bonding layer, the glass substrate, and the second bonding layer are arranged in this order, and the elastic modulus and thickness of each layer satisfy the above formula (2), thereby improving impact resistance while maintaining good flex resistance. The reason for this is presumed to be as follows.

[0335] The inventors of the present disclosure conducted extensive research into the impact resistance and flex resistance of a laminate having a substrate layer, a bonding layer, a glass substrate, and a second bonding layer in this order. The second bonding layer is typically softer than the glass substrate and substrate layer and is therefore more susceptible to deformation upon impact. Therefore, when an impact is applied to the laminate, if the second bonding layer deforms to a large extent, instantaneous and localized deformation is likely to occur in the glass substrate. In this case, there is a concern that the glass substrate may be more susceptible to bending fracture. On the other hand, if the thickness of the second bonding layer is relatively thin, bending fracture of the glass substrate may be suppressed. Furthermore, if the hardness of the second bonding layer is relatively high, bending fracture of the glass substrate may also be suppressed. However, even if bending fracture of the glass substrate can be suppressed by making the thickness of the second bonding layer relatively thin or increasing the hardness of the second bonding layer, Hertzian fracture of the glass substrate cannot be suppressed. To suppress Hertzian fracture of the glass substrate, it is preferable to relatively thicken the substrate layer and the bonding layer or relatively harden the substrate layer and the bonding layer. Furthermore, among the thicknesses of each layer, the thickness of the glass substrate has the greatest effect on impact fracture of the glass substrate. However, even if Hertzian fracture of the glass substrate can be suppressed by relatively thickening the substrate layer and the bonding layer or relatively hardening the substrate layer and the bonding layer, there is a risk of a decrease in flex resistance. Furthermore, even if impact fracture of the glass substrate can be suppressed by increasing the thickness of the glass substrate, there is a risk of a decrease in flex resistance. Based on the influence of the thickness and hardness of each layer on impact resistance and flex resistance and the experimental results described in the Examples and Comparative Examples below, the above formula (2) was derived, which shows the correlation between the thickness and elastic modulus of each layer and impact resistance and flex resistance.

[0336] If the value of the middle part of the above formula (2) is too small, the thickness of the second bonding layer becomes relatively large, or the storage modulus of the second bonding layer becomes relatively low. This may result in the glass substrate being more susceptible to bending fracture and reduced impact resistance. On the other hand, if the value of the middle part of the above formula (2) is too large, the thicknesses of the glass substrate, base layer, and bonding layer become relatively large, or the composite modulus of the base layer and bonding layer becomes relatively high. This may result in reduced flex resistance. Therefore, in this embodiment, by ensuring that the modulus and thickness of each layer satisfy the above formula (2), it is possible to improve impact resistance while maintaining good flex resistance.

[0337] Thus, in this embodiment, it is possible to improve impact resistance while maintaining good bending resistance. Moreover, even if the glass substrate in the laminate is broken, the risk of injury to the human body can be reduced, making it possible to provide a highly safe laminate. Therefore, the laminate in this embodiment can be bent and used for a wide variety of applications. The laminate in this embodiment can be used, for example, in a wide variety of display devices, and specifically, can be used as a member for a foldable display.

[0338] The laminate in this embodiment satisfies the following formula (2). 0.001≦{(E2×D2 2 +E3×D3 2 )×E4×D4 2 ×E5×1000} / D5≦3.0 (2) (In the above formula (2), E2 represents the composite elastic modulus (GPa) of the base layer, D2 represents the thickness (mm) of the base layer, E3 represents the composite elastic modulus (GPa) of the bonding layer, D3 represents the thickness (mm) of the bonding layer, E4 represents the composite elastic modulus (GPa) of the glass base, D4 ​​represents the thickness (mm) of the glass base, E5 represents the storage modulus (GPa) of the second bonding layer, and D5 represents the thickness (mm) of the second bonding layer.)

[0339] The value of the middle part of the above formula (2) is 0.001 or more and 3 or less, preferably 0.0015 or more and 1.5 or less, more preferably 0.003 or more and 1 or less, even more preferably 0.005 or more and 0.7 or less, and particularly preferably 0.01 or more and 0.4 or less. As described above, if the value of the middle part of the above formula (2) is too small, the thickness of the second bonding layer becomes relatively large, or the storage modulus of the second bonding layer becomes relatively low. This may result in the glass substrate being more susceptible to bending fracture and reduced impact resistance. On the other hand, if the value of the middle part of the above formula (2) is too large, the thicknesses of the glass substrate, substrate layer, and bonding layer become relatively large, or the composite modulus of the substrate layer and bonding layer become relatively high. This may result in reduced bending resistance.

[0340] Furthermore, as described above, even if bending fracture of the glass substrate can be suppressed by relatively thinning the thickness of the second bonding layer or by relatively increasing the hardness of the second bonding layer, Hertzian fracture of the glass substrate cannot be suppressed. Therefore, when the value of the middle part of the above formula (2) exceeds a certain value, the effect of suppressing bending fracture of the glass substrate becomes saturated. Therefore, it is preferable that the value of the middle part of the above formula (2) is 0.4 or less.

[0341] The thickness of the substrate layer, the thickness of the bonding layer, the thickness of the glass substrate, and the thickness of the second bonding layer are the same as the thickness of each layer in the laminate of the first embodiment.

[0342] The composite elastic modulus of the substrate layer is the same as the composite elastic modulus of the substrate layer in the first embodiment.

[0343] The composite elastic modulus of the bonding layer is the same as the composite elastic modulus of the bonding layer in the first embodiment.

[0344] The complex elastic modulus of the glass substrate is the same as the complex elastic modulus of the glass substrate in the second embodiment.

[0345] The storage modulus of the second bonding layer is the storage modulus at 20° C. The storage modulus of the second bonding layer is the same as the storage modulus of the second bonding layer in the first embodiment.

[0346] The substrate layer, bonding layer, glass substrate, and second bonding layer in this embodiment are the same as the respective layers in the first embodiment.

[0347] The laminate of this embodiment may further include a functional layer on the surface of the substrate layer opposite the bonding layer, between the substrate layer and the bonding layer, between the glass substrate and the bonding layer, or between the glass substrate and the second bonding layer. The functional layer is the same as the functional layer in the first embodiment.

[0348] In the laminate of this embodiment, a protective film may be disposed on the surface of the base layer opposite to the bonding layer, which is the same as the protective film in the first embodiment.

[0349] The properties and uses of the laminate of this embodiment are similar to those of the laminate of the first embodiment.

[0350] B.Display device The display device according to the present disclosure includes a display panel and the laminate described above, which is disposed on the viewer side of the display panel, with the laminate disposed so that the surface of the laminate facing the glass substrate faces the display panel. That is, the display device according to the present disclosure includes a display panel and the laminate described above, which is disposed on the viewer side of the display panel, with the surface of the laminate facing the glass substrate adjacent to the display panel.

[0351] Fig. 9 is a schematic cross-sectional view showing an example of a display device according to the present disclosure. As shown in Fig. 9, a display device 30 includes a display panel 31 and a laminate 1 disposed on the viewer's side of the display panel 31. The laminate 1 is disposed so that the surface of the laminate 1 facing the glass substrate 2 is adjacent to the display panel 31. In the display device 30, the laminate 1 is used as a member disposed on the surface of the display device 30, and an adhesive layer 32 is disposed between the laminate 1 and the display panel 31.

[0352] The laminate in the present disclosure can be the same as the laminate described above.

[0353] Examples of the display panel in the present disclosure include display panels used in display devices such as liquid crystal display devices, organic EL display devices, and LED display devices.

[0354] The display device according to the present disclosure may have a touch panel member between the display panel and the laminate.

[0355] The display device according to the present disclosure is preferably a flexible display. In particular, the display device according to the present disclosure is preferably foldable. That is, the display device according to the present disclosure is more preferably a foldable display. Since the display device according to the present disclosure has the above-described laminate, it has excellent impact resistance and bending resistance, and is suitable as a flexible display, and further as a foldable display.

[0356] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Example]

[0357] The present disclosure will be further described below with reference to examples and comparative examples.

[0358] [Comparative Example 1] A chemically strengthened glass substrate with a thickness of 70 μm was used.

[0359] [Example 1] (1) Preparation of hard coat film (1-1) Preparation of base layer A tetracarboxylic dianhydride represented by the following chemical formula was synthesized with reference to Synthesis Example 1 of WO 2014 / 046180.

[0360] [ka]

[0361] A 500 mL separable flask was purged with nitrogen and a solution containing 293.29 g of dehydrated dimethylacetamide (DMAc) and 14.3 g (44.7 mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) was dissolved. The temperature was controlled at 30°C. 24.8 g (40.1 mmol) of tetracarboxylic dianhydride (TMPBPTME) was gradually added so that the temperature did not rise more than 2°C. The mixture was stirred for 3 hours with a mechanical stirrer. 0.91 g (4.5 mmol) of terephthalic acid dichloride (TPC) was then added and stirred for another 3 hours to obtain a polyamic acid solution. Next, 6.66 g (84.2 mmol) of pyridine catalyst and 8.60 g (84.2 mmol) of acetic anhydride were added. The mixture was stirred at 25°C for 30 minutes to confirm the homogeneity of the solution. The mixture was then heated to 70°C and stirred for 1 hour. After cooling to room temperature, 174.26 g of 2-propyl alcohol (IPA) was gradually added to the solution, resulting in a slightly cloudy solution. 435.64 g of IPA was added to the cloudy solution all at once, resulting in a white slurry. The slurry was filtered and washed five times with IPA, then dried in an oven heated to 100°C under reduced pressure for six hours to obtain a polyamideimide powder (37.1 g). The weight-average molecular weight of the polyamideimide measured by GPC was 62,000.

[0362] DMAc was added to polyamideimide to prepare a polyamideimide varnish with a polyamideimide content of 19% by mass. The viscosity of the polyamideimide varnish (solid content of 19% by mass) at 25°C was 4000 mPa·s.

[0363] A polyamideimide varnish (solid content concentration 19% by mass) was applied to a glass plate so that the film thickness after drying in a circulation oven described below would be the thickness shown in Table 1. The film was then dried in a circulation oven at 120°C for 10 minutes, cooled to 25°C, and the polyimide resin coating film was peeled off.

[0364] The peeled polyimide-based resin coating film was cut into a size of 150 mm x 200 mm. The cut polyimide-based resin coating film was sandwiched between two metal frames (external dimensions 150 mm x 200 mm, internal dimensions 130 mm x 180 mm), and the metal frames and polyimide-based resin coating film were fixed in place with a fixture. The fixed polyimide-based resin coating film was heated to 300°C at a rate of 10°C / min in a circulating oven under a nitrogen stream (oxygen concentration 100 ppm or less), held at 300°C for 1 hour, and then cooled to 25°C to produce a single-layer polyimide-based resin film.

[0365] (1-2) Formation of hard coat layer The components were blended to obtain the composition shown below to prepare a curable resin composition for a hard coat layer.

[0366] <Composition of Curable Resin Composition for Hard Coat Layer> 25 parts by weight of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (M403, manufactured by Toagosei Co., Ltd.) Dipentaerythritol EO-modified hexaacrylate (A-DPH-6E, manufactured by Shin-Nakamura Chemical Co., Ltd.) 25 parts by mass 50 parts by weight (solid equivalent) of irregular silica particles (average particle size 25 nm, manufactured by JGC Catalysts and Chemicals) Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Omnirad184", manufactured by IGM Resins BV) 4 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Ultraviolet absorber 1 (DAINSORB P6, manufactured by Daiwa Kasei) 3 parts by weight Solvent (MIBK) 150 parts by weight

[0367] Next, the composition for a hard coat layer was applied onto the substrate layer so that the film thickness after curing would be 10 μm, and after drying at 70° C. for 1 minute, the composition was exposed to an irradiation dose of 200 mJ / cm 2 2 The resulting composition was cured by irradiating it with ultraviolet light at a temperature of 100° C. to form a hard coat layer, thereby obtaining a hard coat film.

[0368] (2) Fabrication of the laminate A 25 μm thick adhesive layer (acrylic adhesive sheet, OCA) (3M "8146-1") was attached to the substrate layer side of the hard coat film using a hand roller to obtain a hard coat film with an adhesive layer. Next, the adhesive layer side of the hard coat film with an adhesive layer was attached to a 70 μm thick chemically strengthened glass substrate using a hand roller to obtain a laminate.

[0369] [Examples 2 to 9 and Comparative Examples 2 to 4] A laminate was obtained in the same manner as in Example 1, except that the thickness of the base layer of the hard coat film was changed as shown in Table 1 below, and when the thickness of the bonding layer was 15 μm, 10 μm, or 5 μm, "Panaclean PD-S1" manufactured by Panac Corporation was used as the bonding layer (acrylic adhesive sheet, OCA).

[0370] [Example 10] (1) Preparation of hard coat film A hard coat film was prepared in the same manner as in Example 7.

[0371] (2) Formation of a heat-sensitive adhesive layer The components were mixed to obtain the composition shown below to prepare a heat-sealable resin composition.

[0372] <Composition of Heat-Sealable Resin Composition> Amorphous polyester resin (Vylon 560, manufactured by Toyobo Co., Ltd.) 100 parts by weight Hexanemethylene diisocyanate (Coronate 2203, manufactured by Nippon Polyurethane Industry Co., Ltd.) 5 parts by mass Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 310 parts by weight Solvent (toluene) 310 parts by mass

[0373] Next, the heat-sealable resin composition was applied to the substrate layer side of the hard coat film so that the film thickness after drying would be 5 μm, and dried at 70°C for 1 minute to form a heat-sensitive adhesive layer, thereby obtaining a hard coat film with a heat-sensitive adhesive layer.

[0374] (3) Fabrication of the laminate The hard-coated film with the heat-sensitive adhesive layer was placed on a 70 μm-thick chemically strengthened glass substrate with the heat-sensitive adhesive layer facing the substrate. A 2 mm-thick glass support substrate was placed on the side of the glass substrate opposite the hard-coated film with the heat-sensitive adhesive layer. The hard-coated film with the heat-sensitive adhesive layer and the glass substrate were heated and bonded together using a roll laminator (manufactured by Aco Brands Japan, product name: Desktop Roll Laminator B35A3) to obtain a laminate. The roll temperature was 140°C to 149°C, and the feed rate was 0.3 m / min. The laminate was then aged at 70°C for 2 days.

[0375] [Examples 11 to 14 and Comparative Example 5] A laminate was obtained in the same manner as in Example 10, except that the thickness of the bonding layer was changed as shown in Table 1 below.

[0376] [Example 15] A laminate was obtained in the same manner as in Example 10, except that a pressure-sensitive adhesive layer was formed instead of a heat-sensitive adhesive layer, and the roll temperature was set to 20°C to 30°C in producing the laminate.

[0377] (Formation of pressure-sensitive adhesive layer) The components were mixed to give the composition shown below to prepare a pressure-sensitive adhesive composition.

[0378] <Composition of Pressure-Sensitive Adhesive Composition> Polyether urethane resin 100 parts by mass Hexanemethylene diisocyanate (Coronate 2203, manufactured by Nippon Polyurethane Industry Co., Ltd.) 5 parts by mass Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 310 parts by weight Solvent (toluene) 310 parts by mass

[0379] The pressure-sensitive adhesive composition was applied to the surface of the hard coat film on the substrate layer side so that the film would have a dry thickness of 5 μm, and dried at 70° C. for 1 minute to form a pressure-sensitive adhesive layer.

[0380] [Example 16] A laminate was obtained in the same manner as in Example 7, except that a 5 μm-thick optically transparent adhesive film (OCA) (“D692” manufactured by Lintec Corporation) was used as the bonding layer.

[0381] [Example 17] A laminate was obtained in the same manner as in Example 10, except that the heat-sealable resin composition shown below was used.

[0382] <Composition of Heat-Sealable Resin Composition> Modified polyolefin resin 100 parts by mass Hexanemethylene diisocyanate (Coronate 2203, manufactured by Nippon Polyurethane Industry Co., Ltd.) 5 parts by mass Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 310 parts by weight Solvent (toluene) 310 parts by mass

[0383] [Example 18] A laminate was obtained in the same manner as in Example 10, except that the heat-sealable resin composition shown below was used.

[0384] <Composition of Heat-Sealable Resin Composition> Polyester urethane resin (UR-8300, solid content 30%, manufactured by Toyobo Co., Ltd.) 100 parts by weight Hexanemethylene diisocyanate (Coronate 2203, manufactured by Nippon Polyurethane Industry Co., Ltd.) 1.5 parts by mass Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.5 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 58 parts by weight Solvent (toluene) 58 parts by mass

[0385] [Example 19] A laminate was obtained in the same manner as in Example 10, except that the heat-sealable resin composition shown below was used.

[0386] <Composition of Heat-Sealable Resin Composition> Polyester urethane resin (UR-5537, solid content 30%, manufactured by Toyobo Co., Ltd.) 100 parts by weight Hexanemethylene diisocyanate (Coronate 2203, manufactured by Nippon Polyurethane Industry Co., Ltd.) 1.5 parts by mass Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.5 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 58 parts by weight Solvent (toluene) 58 parts by mass

[0387] [Example 20] A laminate was obtained in the same manner as in Example 10, except that the heat-sealable resin composition shown below was used.

[0388] <Composition of Heat-Sealable Resin Composition> Amorphous polyester resin (Vylon 240, manufactured by Toyobo Co., Ltd.) 100 parts by weight Hexanemethylene diisocyanate (Coronate 2203, manufactured by Nippon Polyurethane Industry Co., Ltd.) 5 parts by mass Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 310 parts by weight Solvent (toluene) 310 parts by mass

[0389] [Example 21] A laminate was obtained in the same manner as in Example 10, except that the heat-sealable resin composition shown below was used.

[0390] <Composition of Heat-Sealable Resin Composition> Amorphous polyester resin (Vylon 600, manufactured by Toyobo Co., Ltd.) 100 parts by weight Hexanemethylene diisocyanate (Coronate 2203, manufactured by Nippon Polyurethane Industry Co., Ltd.) 5 parts by mass Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 310 parts by weight Solvent (toluene) 310 parts by mass

[0391] [Example 22] (1) Preparation of hard coat film A hard coat film was prepared in the same manner as in Example 7.

[0392] (2) Formation of adhesive layer The components were mixed to obtain the composition shown below to prepare an ultraviolet-curable resin composition.

[0393] <Composition of UV-curable resin composition> Urethane acrylate (product name "UV-3310B", manufactured by Mitsubishi Chemical Corporation): 35 parts by weight Ethoxylated pentaerythritol tetraacrylate (product name "ATM-35E", manufactured by Shin-Nakamura Chemical Co., Ltd.): 10 parts by mass Phenoxyethyl acrylate (product name "Viscoat #192", manufactured by Osaka Organic Chemical Industry Co., Ltd.): 5 parts by mass Mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (product name "KAYARAD PET-30", manufactured by Nippon Kayaku Co., Ltd.): 50 parts by mass Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Omnirad184", manufactured by IGM Resins BV): 5 parts by mass Methyl isobutyl ketone: 10 parts by weight

[0394] Next, the above ultraviolet-curable resin composition was applied to the surface of the hard coat film on the substrate layer side so that the film thickness after curing would be 5 μm, and dried at 70°C for 1 minute to form an adhesive layer, thereby obtaining a hard coat film with an adhesive layer.

[0395] (3) Fabrication of the laminate The adhesive layer side of the hard coat film with the adhesive layer was attached to a chemically strengthened glass substrate having a thickness of 70 μm using a hand roller. Next, an irradiation dose of 400 mJ / cm 2 was applied from the hard coat film side. 2 The adhesive layer was cured by irradiating it with ultraviolet light at 1000 kJ / cm 2 , to obtain a laminate.

[0396] [Example 23] (1) Preparation of hard coat film A hard coat film was prepared in the same manner as in Example 7.

[0397] (2) Formation of adhesive layer The components were mixed to obtain the composition shown below to prepare a thermosetting resin composition.

[0398] <Composition of Thermosetting Resin Composition> Special novolac epoxy resin (jER157S65, manufactured by Mitsubishi Chemical) 25 parts by weight Bis-A / Bis-F mixed epoxy resin (jER4250, manufactured by Mitsubishi Chemical) 75 parts by weight 2-Ethyl-4-methylimidazole (Tokyo Chemical Industry Co., Ltd.) 6.5 parts by mass Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 600 parts by weight

[0399] Next, the above-mentioned thermosetting resin composition was applied to the surface of the hard coat film on the substrate layer side so that the film thickness after curing would be 5 μm, and dried at 70°C for 1 minute to form an adhesive layer, thereby obtaining a hard coat film with an adhesive layer.

[0400] (3) Fabrication of the laminate The adhesive layer side of the hard coat film with the adhesive layer was attached to a chemically strengthened glass substrate with a thickness of 70 μm using a hand roller, and then heated at 130° C. for 60 minutes to cure the adhesive layer, thereby obtaining a laminate.

[0401] [Example 24] A laminate was obtained in the same manner as in Example 23, except that the following thermosetting resin composition was used.

[0402] <Composition of Thermosetting Resin Composition> Special novolac epoxy resin (jER157S65, manufactured by Mitsubishi Chemical) 50 parts by weight Bis-A type epoxy resin (jER1256, manufactured by Mitsubishi Chemical) 50 parts by weight 2-Ethyl-4-methylimidazole (Tokyo Chemical Industry Co., Ltd.) 6.5 parts by mass Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 600 parts by weight

[0403] [Example 25] (1) Preparation of hard coat film A hard-coated film was produced in the same manner as in Example 10, except that a 60 μm thick TAC film ("TG60UL" manufactured by Fujifilm Corporation) was used as the substrate layer and the thickness of the hard-coat layer was changed as shown in Table 1 below.

[0404] (2) Formation of a heat-sensitive adhesive layer In the same manner as in Example 10, a hard-coated film with a heat-sensitive adhesive layer was obtained.

[0405] (3) Fabrication of the laminate A laminate was obtained in the same manner as in Example 10.

[0406] [Example 26] (1) Preparation of hard coat film A hard coat film was produced in the same manner as in Example 10, except that a 50 μm thick PET film ("A4360 (current product number)" ("A4300 (old product number)") manufactured by Toyobo Co., Ltd.) was used as the substrate layer and the thickness of the hard coat layer was changed as shown in Table 1 below.

[0407] (2) Formation of a heat-sensitive adhesive layer In the same manner as in Example 10, a hard-coated film with a heat-sensitive adhesive layer was obtained.

[0408] (3) Fabrication of the laminate A laminate was obtained in the same manner as in Example 10.

[0409] [Example 27] A laminate was produced in the same manner as in Example 26, except that a 50 μm thick PEN film (manufactured by Teijin Ltd.) was used as the base layer.

[0410] [Examples 28 to 30 and Comparative Example 6] Laminates were obtained in the same manner as in Example 10, except that the thickness of the glass substrate was changed as shown in Table 3 below.

[0411] [Rating 1] (1)Pencil hardness First, a 100 μm-thick PET film ("A4160 (current product number)" ("A4100 (old product number)"), composite modulus 6.9 GPa), manufactured by Toyobo Co., Ltd., was bonded to the glass substrate-side surface of the laminate for Examples 1 to 30 and Comparative Examples 2 to 6, or to the glass substrate for Comparative Example 1, via a 50 μm-thick optically transparent adhesive film (OCA) ("8146-2" manufactured by 3M Corporation, composite modulus 9.6 MPa), to prepare a test laminate. For the laminates of Examples 1 to 30 and Comparative Examples 2 to 6, the pencil hardness was measured on the surface of the hard coat film side of the test laminate. For the glass substrate of Comparative Example 1, the pencil hardness was measured on the surface of the test laminate on the glass substrate side. Here, the pencil hardness was measured in accordance with JIS K5600-5-4 (1999). In addition, a pencil hardness tester (product name: "Pencil Scratch Coating Hardness Tester (Electric)", manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used, and the measurement conditions were an angle of 45°, a load of 1 kg, a speed of 0.5 mm / sec or more and 1 mm / sec or less, and a temperature of 23±2°C.

[0412] For Examples 1 to 9 and Comparative Examples 1 to 4, the pencil hardness was evaluated according to the following criteria. 2A: Pencil hardness is 5H or more. A: Pencil hardness is 4H. B: Pencil hardness is 3H. C: Pencil hardness is H. D: Pencil hardness is less than H.

[0413] For Examples 10 to 30 and Comparative Examples 5 and 6, the pencil hardness was evaluated according to the following criteria. 2A: Pencil hardness is 5H or more. A: Pencil hardness is 4H. B: Pencil hardness is 3H. C: Pencil hardness is less than 3H.

[0414] (2) Impact test (pen drop test) A pen drop test was performed as an impact test on the laminates of Examples 1 to 30 and Comparative Examples 2 to 6, and the glass substrate of Comparative Example 1. First, a 100 μm-thick PET film ("A4160 (current product number)" ("A4100 (old product number)"), composite modulus 6.9 GPa), manufactured by Toyobo Co., Ltd., was bonded to the glass substrate side of the laminate for Examples 1 to 30 and Comparative Examples 2 to 6, or to the glass substrate for Comparative Example 1, via a 50 μm-thick optically transparent adhesive film (OCA) ("8146-2" manufactured by 3M Corporation, composite modulus 9.6 MPa) between them, to prepare a test laminate. The test laminate was placed on a 30 mm-thick metal plate so that the surface of the PET film side of the test laminate was in contact with the metal plate. Next, a pen was dropped from a test height onto the center of the test laminate, with its tip pointing down. The pen used was a Zebra Blen 0.5BAS88-BK (weight 12 g, pen tip 0.5 mmφ). Tables 1 to 3 show the maximum test height at which the glass substrate did not crack. Note that a larger value indicates higher impact resistance.

[0415] (3) Puncture test The above-mentioned piercing test was carried out to measure the piercing breaking strength for the laminate of Example 10 and the glass substrate of Comparative Example 1. Note that a larger value indicates higher impact resistance.

[0416] (4) Dynamic bending test The laminates of Examples 1 to 30 and Comparative Examples 2 to 6 and the glass substrate of Comparative Example 1 were subjected to the dynamic bending test described above to evaluate their bending resistance. The distance d between the two opposing short sides of the laminate or glass substrate was 3 mm, 4 mm, 6 mm, 8 mm, or 10 mm. The laminates were bent 200,000 times with the surface on the glass substrate side facing outward and the surface on the hard coat film side facing inward. The results of the dynamic bending test were evaluated according to the following criteria. 4A: No cracks, breaks, or peeling in the laminate or glass substrate even when the gap d is 3 mm 3A: No cracks, breaks, or peeling in the laminate or glass substrate even when the gap d is 4 mm 2A: No cracks, breaks, or peeling in the laminate or glass substrate even when the gap d is 6 mm A: No cracks, breaks, or peeling in the laminate or glass substrate even when the gap d is 8 mm B: No cracks, breaks, or peeling in the laminate or glass substrate at a distance d of 10 mm C: When the gap d was 10 mm, cracks, breakage, and peeling occurred in the laminate or glass substrate.

[0417] (5) Composite modulus For the laminates of Examples 1 to 30 and Comparative Examples 2 to 6, the composite elastic modulus of the base layer and the bonding layer was measured by the above-mentioned method for measuring the composite elastic modulus.

[0418] (6) Glass transition temperature (Tg) For the laminates of Examples 1 to 30 and Comparative Examples 2 to 6, the glass transition temperatures of the bonding layers were measured by the above-mentioned method for measuring glass transition temperatures.

[0419] [Table 1]

[0420] [Table 2]

[0421] [Table 3]

[0422] From Tables 1 to 3, it was confirmed that when the thickness ratio (A+B) / C is within a predetermined range, the impact resistance and flex resistance are good, and further, the surface hardness is high and the scratch resistance is good.

[0423] [Example 31] A second bonding layer (optically transparent adhesive film (OCA), storage modulus 0.10 MPa) having a thickness of 100 μm was attached to the glass substrate side of the laminate of Example 10 using a hand roller to obtain a laminate.

[0424] [Example 32] A laminate was produced in the same manner as in Example 31, except that a 100 μm thick optically transparent adhesive film (OCA) (3M's "8146-4", storage modulus 0.23 MPa) was used as the second bonding layer.

[0425] [Example 33] A laminate was produced in the same manner as in Example 31, except that a 50 μm thick optically transparent adhesive film (OCA) (3M's "8146-2", storage modulus 0.23 MPa) was used as the second bonding layer.

[0426] [Example 34] A laminate was produced in the same manner as in Example 31, except that a 50 μm-thick optically transparent adhesive film (OCA) (storage modulus: 0.10 MPa) was used as the second bonding layer.

[0427] [Example 35] A laminate was produced in the same manner as in Example 31, except that a 55 μm-thick optically transparent adhesive film (OCA) (storage modulus: 0.12 MPa) was used as the second bonding layer.

[0428] [Example 36] A laminate was produced in the same manner as in Example 31, except that a 30 μm-thick optically transparent adhesive film (OCA) (storage modulus: 0.12 MPa) was used as the second bonding layer.

[0429] [Example 37] A laminate was produced in the same manner as in Example 31, except that a 25 μm-thick optically transparent adhesive film (OCA) (storage modulus: 0.32 MPa) was used as the second bonding layer.

[0430] [Example 38] A laminate was produced in the same manner as in Example 31, except that a 25 μm-thick optically transparent adhesive film (OCA) (storage modulus: 0.15 MPa) was used as the second bonding layer.

[0431] [Example 39] A laminate was produced in the same manner as in Example 31, except that a 25 μm thick optically transparent adhesive film (OCA) (“F619” manufactured by Lintec Corporation, storage modulus 0.19 MPa) was used as the second bonding layer.

[0432] [Example 40] A laminate was produced in the same manner as in Example 31, except that a 25 μm thick optically transparent adhesive film (OCA) (“N632” manufactured by Lintec Corporation, storage modulus 0.20 MPa) was used as the second bonding layer.

[0433] [Example 41] A laminate was produced in the same manner as in Example 31, except that a 25 μm-thick optically transparent adhesive film (OCA) (storage modulus: 0.57 MPa) was used as the second bonding layer.

[0434] [Example 42] A laminate was produced in the same manner as in Example 31, except that a 25 μm-thick optically transparent adhesive film (OCA) (storage modulus: 1.17 MPa) was used as the second bonding layer.

[0435] [Example 43] A laminate was produced in the same manner as in Example 31, except that a 25 μm thick optically transparent adhesive film (OCA) ("D692" manufactured by Lintec Corporation, storage modulus 2.33 MPa) was used as the second bonding layer.

[0436] [Example 44] A laminate was produced in the same manner as in Example 31, except that a 25 μm-thick optically transparent adhesive film (OCA) (storage modulus: 2.22 MPa) was used as the second bonding layer.

[0437] [Example 45] A laminate was produced in the same manner as in Example 31, except that a 15 μm thick optically transparent adhesive film (OCA) ("D692" manufactured by Lintec Corporation, storage modulus 2.14 MPa) was used as the second bonding layer.

[0438] [Example 46] A laminate was produced in the same manner as in Example 31, except that a 15 μm-thick optically transparent adhesive film (OCA) (storage modulus: 0.12 MPa) was used as the second bonding layer.

[0439] [Example 47] A laminate was produced in the same manner as in Example 31, except that a 5 μm-thick optically transparent adhesive film (OCA) (storage modulus: 0.91 MPa) was used as the second bonding layer.

[0440] [Example 48] A laminate was produced in the same manner as in Example 31, except that a 10 μm-thick optically transparent adhesive film (OCA) (storage modulus: 2.22 MPa) was used as the second bonding layer.

[0441] [Example 49] A laminate was produced in the same manner as in Example 31, except that a 5 μm-thick optically transparent adhesive film (OCA) (storage modulus: 1.95 MPa) was used as the second bonding layer.

[0442] Comparative Example 7 A laminate was produced in the same manner as in Example 31, except that a 5 μm-thick optically transparent adhesive film (OCA) (storage modulus: 2.22 MPa) was used as the second bonding layer.

[0443] [Comparative Example 8] A laminate was produced in the same manner as in Example 31, except that a 15 μm-thick optically transparent adhesive film (OCA) (storage modulus: 12.74 MPa) was used as the second bonding layer.

[0444] [Example 50] A 50 μm thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of the laminate of Example 18 using a hand roller to obtain a laminate.

[0445] [Example 51] A 50 μm thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of the laminate of Example 19 using a hand roller to obtain a laminate.

[0446] [Example 52] A 50 μm thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of the laminate of Example 20 using a hand roller to obtain a laminate.

[0447] [Example 53] A 50 μm thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of the laminate of Example 21 using a hand roller to obtain a laminate.

[0448] [Example 54] A 50 μm thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of the laminate of Example 22 using a hand roller to obtain a laminate.

[0449] [Example 55] A 50 μm thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of the laminate of Example 23 using a hand roller to obtain a laminate.

[0450] [Example 56] A 50 μm thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of the laminate of Example 28 using a hand roller to obtain a laminate.

[0451] [Example 57] A laminate was produced in the same manner as in Example 26, except that the thickness of the hard coat layer was 10 μm. A 50 μm-thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of this laminate using a hand roller to obtain a laminate.

[0452] [Example 58] A 50 μm thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of the laminate of Example 26 using a hand roller to obtain a laminate.

[0453] [Example 59] A laminate was produced in the same manner as in Example 57, except that the thickness of the glass substrate was 50 μm.

[0454] [Example 60] A laminate was produced in the same manner as in Example 33, except that a 25 μm-thick optically transparent adhesive film (OCA) (composite modulus of elasticity: 0.0096 GPa) was used as the bonding layer.

[0455] [Example 61] A laminate was produced in the same manner as in Example 59, except that a 50 μm-thick optically transparent adhesive film (OCA) (composite elastic modulus 0.0096 GPa) was used as the bonding layer.

[0456] [Example 62] A laminate was prepared in the same manner as in Example 33, except that the thickness of the glass substrate was 50 μm and a 100 μm thick optically transparent adhesive film (OCA) (3M "8146-4", storage modulus 0.23 MPa) was used as the second bonding layer.

[0457] [Example 63] A laminate was produced in the same manner as in Example 62, except that a 50 μm thick PEN film (manufactured by Teijin Ltd.) was used as the base layer.

[0458] [Example 64] A laminate was produced in the same manner as in Example 62, except that a 50 μm thick PET film ("A4360" manufactured by Toyobo Co., Ltd.) was used as the base layer.

[0459] [Example 65] A laminate was prepared in the same manner as in Example 33, except that the thickness of the glass substrate was 30 μm and a 100 μm thick optically transparent adhesive film (OCA) (3M "8146-4", storage modulus 0.23 MPa) was used as the second bonding layer.

[0460] [Example 66] A laminate was produced in the same manner as in Example 65, except that a 50 μm thick PEN film (manufactured by Teijin Ltd.) was used as the base layer.

[0461] [Example 67] A laminate was produced in the same manner as in Example 65, except that a 50 μm thick PET film ("A4360" manufactured by Toyobo Co., Ltd.) was used as the base layer.

[0462] [Example 68] A laminate was prepared in the same manner as in Example 67, except that a 25 μm thick optically transparent adhesive film (OCA) (composite modulus of elasticity 0.0096 GPa) was used as the bonding layer, and a 25 μm thick optically transparent adhesive film (OCA) (composite modulus of elasticity 0.23 MPa) was used as the second bonding layer.

[0463] [Example 69] A laminate was produced in the same manner as in Example 33, except that the thickness of the substrate layer was 80 μm and the thickness of the glass substrate was 50 μm.

[0464] [Example 70] A laminate was prepared in the same manner as in Example 59, except that a 23 μm thick PET film ("U403" manufactured by Toray Industries, Inc.) was used as the substrate layer and the thickness of the glass substrate was 30 μm.

[0465] Comparative Example 9 A laminate was produced in the same manner as in Example 68, except that a 100 μm thick optically transparent adhesive film (OCA) (3M's "8146-4", storage modulus 0.23 MPa) was used as the second bonding layer.

[0466] [Comparative Example 10] A 100 μm thick optically transparent adhesive film (OCA) (3M "8146-4", storage modulus 0.23 MPa) was attached to one side of a 70 μm thick chemically strengthened glass substrate using a hand roller to obtain a laminate.

[0467] [Comparative Example 11] A laminate was produced in the same manner as in Comparative Example 10, except that the thickness of the glass substrate was 50 μm.

[0468] [Comparative Example 12] A laminate was produced in the same manner as in Comparative Example 10, except that the thickness of the glass substrate was 30 μm.

[0469] [Example 71] A substrate layer made of an 80 μm-thick polyimide resin film was prepared in the same manner as in Example 1. A heat-sensitive adhesive layer was formed on one side of the substrate layer in the same manner as in Example 10, yielding a substrate layer with a heat-sensitive adhesive layer. The substrate layer with a heat-sensitive adhesive layer was placed so that the side of the substrate layer with the heat-sensitive adhesive layer was in contact with a 70 μm-thick chemically strengthened glass substrate, and a 2 mm-thick glass support substrate was placed on the side of the glass substrate opposite the substrate layer with the heat-sensitive adhesive layer. The substrate layer with the heat-sensitive adhesive layer and the glass substrate were heated and bonded together using a roll laminator (manufactured by Aco Brands Japan, product name: Desktop Roll Laminator B35A3) to obtain a laminate. The roll temperature was 140°C to 149°C, and the feed rate was 0.3 m / min. The laminate was then aged at 70°C for 2 days. Next, a 50 μm thick optically transparent adhesive film (OCA) (3M "8146-2", storage modulus 0.23 MPa) was attached to the glass substrate side of the laminate using a hand roller to obtain a laminate.

[0470] [Example 72] A laminate was produced in the same manner as in Example 71, except that the thickness of the substrate layer was set to 50 μm.

[0471] [Example 73] A laminate was produced in the same manner as in Example 71, except that the thickness of the substrate layer was 50 μm and the thickness of the glass substrate was 50 μm.

[0472] [Example 74] A laminate was produced in the same manner as in Example 71, except that the thickness of the substrate layer was 50 μm and the thickness of the glass substrate was 30 μm.

[0473] [Example 75] A laminate was produced in the same manner as in Example 71, except that the thickness of the substrate layer was 30 μm.

[0474] [Example 76] A laminate was produced in the same manner as in Example 71, except that a 75 μm thick PET film ("A4360" manufactured by Toyobo Co., Ltd.) was used as the base layer.

[0475] [Example 77] A laminate was produced in the same manner as in Example 71, except that a 50 μm thick PET film ("A4360" manufactured by Toyobo Co., Ltd.) was used as the base layer.

[0476] [Example 78] A laminate was produced in the same manner as in Example 77, except that the thickness of the glass substrate was 50 μm.

[0477] [Example 79] A laminate was produced in the same manner as in Example 77, except that the thickness of the glass substrate was 30 μm.

[0478] [Example 80] A laminate was produced in the same manner as in Example 71, except that a 23 μm thick PET film ("U403" manufactured by Toray Industries, Inc.) was used as the base layer.

[0479] [Example 81] A laminate was produced in the same manner as in Example 71, except that a TAC film (manufactured by Fujifilm Corporation, "TG60UL") having a thickness of 60 μm was used as the base layer.

[0480] [Example 82] A laminate was produced in the same manner as in Example 71, except that a 50 μm thick PEN film (manufactured by Teijin Ltd.) was used as the base layer.

[0481] [Example 83] A laminate was prepared in the same manner as in Example 71, except that the thickness of the glass substrate was 50 μm and a 100 μm thick optically transparent adhesive film (OCA) (3M "8146-4", storage modulus 0.23 MPa) was used as the second bonding layer.

[0482] [Example 84] A laminate was produced in the same manner as in Example 83, except that a 50 μm thick PEN film (manufactured by Teijin Ltd.) was used as the base layer.

[0483] [Example 85] A laminate was produced in the same manner as in Example 83, except that a 50 μm thick PET film ("A4360" manufactured by Toyobo Co., Ltd.) was used as the base layer.

[0484] [Example 86] A laminate was prepared in the same manner as in Example 71, except that the thickness of the glass substrate was 30 μm and a 100 μm thick optically transparent adhesive film (OCA) (3M "8146-4", storage modulus 0.23 MPa) was used as the second bonding layer.

[0485] [Example 87] A laminate was produced in the same manner as in Example 86, except that a 50 μm thick PEN film (manufactured by Teijin Ltd.) was used as the base layer.

[0486] [Example 88] A laminate was produced in the same manner as in Example 86, except that a 50 μm thick PET film ("A4360" manufactured by Toyobo Co., Ltd.) was used as the base layer.

[0487] [Example 89] A laminate was obtained in the same manner as in Example 88, except that a 25 μm thick optically transparent adhesive film (OCA) (composite elastic modulus 0.0096 GPa) was used as the bonding layer, and a 100 μm thick optically transparent adhesive film (OCA) (3M "8146-4", storage modulus 0.23 MPa) was used as the second bonding layer.

[0488] [Example 90] A laminate was obtained in the same manner as in Example 72, except that a 15 μm-thick optically transparent adhesive film (OCA) (storage modulus: 2.14 MPa) was used as the second bonding layer.

[0489] [Example 91] A laminate was obtained in the same manner as in Example 72, except that a 5 μm-thick optically transparent adhesive film (OCA) (storage modulus: 0.91 MPa) was used as the second bonding layer.

[0490] [Example 92] A laminate was obtained in the same manner as in Example 72, except that a 10 μm-thick optically transparent adhesive film (OCA) (storage modulus: 2.22 MPa) was used as the second bonding layer.

[0491] [Example 93] A laminate was obtained in the same manner as in Example 72, except that a 5 μm-thick optically transparent adhesive film (OCA) (storage modulus: 1.95 MPa) was used as the second bonding layer.

[0492] [Example 94] A laminate was prepared in the same manner as in Example 71, except that a 23 μm thick PET film ("U403" manufactured by Toray Industries, Inc.) was used as the substrate layer and the thickness of the glass substrate was 30 μm.

[0493] [Comparative Example 13] A laminate was obtained in the same manner as in Example 72, except that a 5 μm-thick optically transparent adhesive film (OCA) (storage modulus: 2.22 MPa) was used as the second bonding layer.

[0494] [Comparative Example 14] A laminate was obtained in the same manner as in Example 94, except that a 100 μm thick optically transparent adhesive film (OCA) (“8146-4” manufactured by 3M, storage modulus 0.23 MPa) was used as the second bonding layer.

[0495] [Rating 2] (1) Impact test (pen drop test) A pen drop test was performed on the laminate as an impact test. First, a 100 μm-thick PET film (Toyobo Co., Ltd., "A4160," composite elastic modulus 6.9 GPa) was attached to the surface of the laminate facing the second bonding layer to prepare a test laminate. 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 from the test height onto the center of the test laminate, with its tip pointing downward. A Zebra Corp. Blen 0.5BAS88-BK pen (weight 12 g, pen tip 0.5 mm diameter) was used. Tables 4 to 6 show the maximum test height at which the glass substrate did not crack. Note that a higher value indicates higher impact resistance.

[0496] (2) Dynamic bending test First, a 38 μm thick PET film ("A4360" manufactured by Toyobo Co., Ltd.) was attached to the second bonding layer side of the laminate with a hand roller to prepare a test laminate. A dynamic bending test was conducted in the same manner as in Evaluation 1 above to evaluate bending resistance. In this case, the test laminate was bent 200,000 times so that the side of the second bonding layer was on the outside and the side of the hard coat layer or base material layer was on the inside.

[0497] (3) Composite Elastic Modulus of the Glass Substrate, the Bonding Layer, the Substrate Layer, and the Hard Coat Layer The composite elastic modulus of the glass substrate, the bonding layer, the substrate layer, and the hard coat was measured by the above-mentioned method for measuring the composite elastic modulus.

[0498] (4) Storage modulus of the second bonding layer at 20°C The storage modulus of the second bonding layer at 20° C. was measured by the above-mentioned method for measuring the storage modulus of the second bonding layer.

[0499] Fig. 10 shows a graph illustrating the relationship between the value of the middle part of the above-mentioned formula (1) and the test height in the pen drop test. Fig. 11 shows a graph illustrating the relationship between the value of the middle part of the above-mentioned formula (2) and the test height in the pen drop test.

[0500] (5) Glass transition temperature (Tg) of the bonding layer and the second bonding layer The glass transition temperatures of the bonding layer and the second bonding layer were measured by the above-mentioned method for measuring glass transition temperature.

[0501] [Table 4]

[0502] [Table 5]

[0503] [Table 6]

[0504] It was confirmed from Tables 4 and 5 and Fig. 10 that when the above formula (1) is satisfied, good flex resistance can be obtained without impairing impact resistance. It was also confirmed from Table 6 and Fig. 11 that when the above formula (2) is satisfied, good flex resistance can be obtained without impairing impact resistance.

[0505] [Example 95] A 50 μm thick PET film ("A4160" manufactured by Toyobo Co., Ltd.) was prepared, and the curable resin composition for the hard coat layer used in Example 1 was applied to the PET film using a bar coater to complete a coating film. The coating film was then dried at 100°C for 3 minutes and then cured by irradiating with 200 mJ of ultraviolet light to form a 10 μm thick hard coat layer. Next, a pressure-sensitive adhesive layer was formed on the surface of the PET film opposite the hard coat layer in the same manner as in Example 15. This resulted in a laminate film. Next, the bonding layer side of the laminate film was attached to a 30 μm thick chemically strengthened glass substrate to obtain a laminate.

[0506] [Example 96] A laminate was produced in the same manner as in Example 95, except that a 5 μm-thick optically transparent adhesive film (OCA) (“D692” manufactured by Lintec Corporation, composite elastic modulus 19 MPa) was used as the bonding layer.

[0507] [Example 97] A laminate was prepared in the same manner as in Example 95, except that a 5 μm thick optically transparent adhesive film (acrylic adhesive sheet, OCA) (Panaclean PD-S1 manufactured by Panac Corporation, composite elastic modulus 13.7 MPa) was used as the bonding layer.

[0508] [Example 98] In the same manner as in Example 95, a hard coat layer was formed on a PET film.

[0509] Next, the heat-sealable resin composition used in Example 17 was applied to the surface of the PET film opposite the hard coat layer so that the film thickness after drying would be 5 μm, and the coating was dried at 70°C for 1 minute to form a heat-sensitive adhesive layer, thereby obtaining a laminated film.

[0510] Next, the laminate film was placed so that the heat-sensitive adhesive layer was in contact with a 30 μm-thick chemically strengthened glass substrate, and a 2 mm-thick glass support substrate was placed on the side of the glass substrate opposite the laminate film. The laminate film and glass substrate were heated and bonded together using a roll laminator (manufactured by Aco Brands Japan, product name: Desktop Roll Laminator B35A3) to obtain a laminate. The roll temperature was 140°C to 149°C, and the feed rate was 0.3 m / min. The laminate was then aged at 70°C for 2 days.

[0511] [Example 99] A laminate was produced in the same manner as in Example 98, except that the heat-sealable resin composition used in Example 10 was used.

[0512] [Example 100] A laminate was produced in the same manner as in Example 98, except that the heat-sealable resin composition used in Example 18 was used.

[0513] [Example 101] A laminate was produced in the same manner as in Example 98, except that the heat-sealable resin composition used in Example 19 was used.

[0514] [Example 102] A laminate was produced in the same manner as in Example 98, except that the heat-sealable resin composition used in Example 21 was used.

[0515] [Example 103] A laminate was produced in the same manner as in Example 98, except that the heat-sealable resin composition used in Example 20 was used.

[0516] [Example 104] In the same manner as in Example 95, a hard coat layer was formed on a PET film.

[0517] Next, the ultraviolet-curable resin composition used in Example 22 was applied to the surface of the PET film opposite to the hard coat layer so that the film thickness after curing would be 5 μm, and the applied film was dried at 70°C for 1 minute to form an adhesive layer, thereby obtaining a laminated film.

[0518] The adhesive layer side of the laminated film was attached to a chemically strengthened glass substrate with a thickness of 30 μm using a hand roller. Next, an irradiation dose of 400 mJ / cm was applied from the hard coat layer side. 2 The adhesive layer was cured by irradiating it with ultraviolet light at 1000 kJ / cm 2 , to obtain a laminate.

[0519] [Example 105] A laminate was produced in the same manner as in Example 98, except that the following heat-sealable resin composition was used.

[0520] <Composition of Heat-Sealable Resin Composition> Amorphous polyester resin (TP-235S20TM, solid content 20%, manufactured by Mitsubishi Chemical Corporation) 100 parts by mass 1 part by mass of hexanemethylene diisocyanate (Coronate 2203, manufactured by Nippon Polyurethane Industry Co., Ltd.) Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent) Solvent (MEK) 34 parts by weight Solvent (toluene) 10 parts by mass

[0521] [Example 106] In the same manner as in Example 95, a hard coat layer was formed on a PET film.

[0522] Next, the thermosetting resin composition used in Example 23 was applied to the surface of the PET film opposite to the hard coat layer so that the film thickness after curing would be 5 μm, and the applied film was dried at 70°C for 1 minute to form an adhesive layer, thereby obtaining a hard coat film with an adhesive layer.

[0523] The adhesive layer side of the hard coat film with the adhesive layer was attached to a chemically strengthened glass substrate with a thickness of 30 μm using a hand roller, and then heated at 130° C. for 60 minutes to cure the adhesive layer, thereby obtaining a laminate.

[0524] [Rating 3] (1)Pencil hardness The pencil hardness of the surface of the laminate on the hard coat layer side was measured in the same manner as in the above Evaluation 1. The pencil hardness was evaluated according to the following criteria. 2A: Pencil hardness is 2H or more. A: Pencil hardness is H. B: Pencil hardness is F. C: Pencil hardness is HB or less.

[0525] (2) Impact test (pen drop test) A pen drop test was performed on the laminate as an impact test in the same manner as in Evaluation 1. Table 7 shows the maximum test height at which no cracks occurred in the glass substrate. Note that a larger value indicates higher impact resistance.

[0526] (3) Dynamic bending test A dynamic bending test was conducted to evaluate the bending resistance in the same manner as in Evaluation 1. The dynamic bending test was conducted under three conditions: (a) a temperature of 23°C, (b) a temperature of 60°C and a humidity of 90% RH, and (c) a temperature of -20°C.

[0527] [Table 7]

[0528] The preferred range of the glass transition temperature of the bonding layer is -40°C or higher and 150°C or lower. However, from the viewpoint of dynamic flexibility in high temperature, high humidity, and low temperature environments, it was suggested that the glass transition temperature of the bonding layer is more preferably -40°C or higher and 25°C or lower, and 50°C or higher and 150°C or lower. [Explanation of symbols]

[0529] 1 ... Laminate 2...Glass substrate 3 … Bonding layer 4...Hard coat film 5 … Base material layer 6...Hard coat layer 7 … Anti-reflection layer 10...Second bonding layer 11... Protective film 12 ... Resin substrate 13… Adhesive layer 14...Second hard coat layer 30…Display device 31... Display panel

Claims

1. A laminate having a hard coat layer, a substrate layer, a bonding layer, a glass substrate, and a second bonding layer in this order, the bonding layer is a layer that bonds the glass substrate and the substrate layer, the second bonding layer is a layer that bonds the laminate to another member, The thickness of the glass substrate is 10 μm or more and 100 μm or less, A laminate satisfying the following formula (1): 0.001≦{(E １ ×D １ ２ +E ２ ×D ２ ２ +E ３ ×D ３ ２ )×E ４ ×D ４ ２ ×E ５ ×1000} / D ５ ≦3.0 (1) (In the above formula (1), E １ is the composite elastic modulus (GPa) of the hard coat layer, D １ is the thickness of the hard coat layer (mm), E ２ is the composite elastic modulus (GPa) of the substrate layer, D ２ is the thickness of the substrate layer (mm), E ３ is the composite elastic modulus of the bonding layer (GPa), D ３ is the thickness of the bonding layer (mm), E ４ is the composite elastic modulus of the glass substrate (GPa), D ４ is the thickness of the glass substrate (mm), E ５ is the storage modulus of the second bonding layer (GPa), D ５ indicates the thickness (mm) of the second bonding layer.

2. A laminate having a base layer, a bonding layer, a glass base material, and a second bonding layer in this order, the bonding layer is a layer that bonds the glass substrate and the substrate layer, the second bonding layer is a layer that bonds the laminate to another member, The thickness of the glass substrate is 10 μm or more and 100 μm or less, A laminate satisfying the following formula (2): 0.001≦{(E ２ ×D ２ ２ +E ３ ×D ３ ２ )×E ４ ×D ４ ２ ×E ５ ×1000} / D ５ ≦3.0 (2) (In the above formula (2), E ２ is the composite elastic modulus (GPa) of the substrate layer, D ２ is the thickness of the substrate layer (mm), E ３ is the composite elastic modulus of the bonding layer (GPa), D ３ is the thickness of the bonding layer (mm), E ４ is the composite elastic modulus of the glass substrate (GPa), D ４ is the thickness of the glass substrate (mm), E ５ is the storage modulus of the second bonding layer (GPa), D ５ indicates the thickness (mm) of the second bonding layer.

3. 3. The laminate according to claim 1, wherein the second bonding layer has a glass transition temperature of −50° C. or higher and 30° C. or lower.

4. The laminate according to claim 1 , wherein the second bonding layer contains an optically transparent adhesive.

5. The laminate according to any one of claims 1 to 4, wherein the bonding layer has a composite elastic modulus of 1 MPa or more and 6000 MPa or less.

6. The laminate according to any one of claims 1 to 5, wherein the glass transition temperature of the bonding layer is -40°C or higher and 150°C or lower.

7. The laminate according to any one of claims 1 to 6, wherein the base layer has a composite elastic modulus of 5.7 GPa or more.

8. The laminate according to any one of claims 1 to 7, wherein the glass substrate is chemically strengthened glass.

9. The laminate according to any one of claims 1 to 8, wherein the bonding layer is a pressure-sensitive adhesive layer, a heat-sensitive adhesive layer, or contains a cured product of a curable adhesive composition.

10. The laminate according to any one of claims 1 to 9, wherein the bonding layer contains at least one resin selected from the group consisting of polyester resin, polyolefin resin, and urethane resin.

11. The laminate according to claim 1 , further comprising an antireflection layer on the side of the hard coat layer opposite to the substrate layer.

12. 12. The laminate according to claim 1, wherein the laminate does not crack, break, or peel when the laminate is repeatedly bent 200,000 times by 180° so that the surface of the laminate facing the glass substrate is on the outside and the surface of the laminate facing the hard coat layer is on the inside, and the distance between opposing sides of the laminate is 10 mm.

13. The laminate according to claim 1 , further comprising a protective film on the side of the hard coat layer opposite to the substrate layer.

14. A display panel; The laminate according to any one of claims 1 to 13, which is disposed on the viewer side of the display panel; wherein the laminate is disposed so that a surface of the laminate on the glass substrate side is adjacent to the display panel.

15. The display device of claim 14, which is a foldable display.

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