Laminate, electronic device, cover glass, and resin composition

Abstract

The purpose of the present invention is to provide a laminate having excellent impact resistance. Another purpose of the present invention is to provide an electronic device and a cover glass using the laminate, and a resin composition for forming a resin layer of the laminate. This laminate has a thin glass sheet having a thickness of 200 [mu] m or less, and a resin layer disposed on at least one side of the thin glass sheet and having a thickness of 5 [mu] m or more, the resin layer having a rupture energy of 1 mJ / mm3 or more and a storage modulus at 25 DEG C of 2500 MPa or less, or the resin layer having a rupture energy of 1 mJ / mm3 or more and a storage modulus at 25 DEG C of 2500 MPa or less. This laminate has a thin glass sheet having a thickness of 200 [mu] m or less, and a resin layer disposed on at least one side of the thin glass sheet and having a thickness of 5 [mu] m or more, wherein the resin layer has a Young's modulus of 50 MPa or more and 1500 MPa or less.

Description

Technical Field

[0001] The present invention relates to a laminate having excellent impact resistance, an electronic device and a cover glass using the laminate, and a resin composition for forming a resin layer of the laminate. Background Art

[0002] In recent years, development has been progressing to enable foldable display screens of electronic devices such as smartphones, electronic books, and tablet PCs. Research is underway to use a flexible thin plate glass on the outermost surface of such a foldable display screen.

[0003] Since thin plate glass is easily broken by impact, research is being conducted to configure a protective resin layer on one surface of the thin plate glass. For example, Patent Document 1 describes a protective substrate for a display device, which includes glass and a resin layer located on one side of the glass. The thickness of the glass is 20 μm to 200 μm, and the specific gravity of the resin layer is 0.9 g / cm 3 ~1.5g / cm 3 The bending elastic modulus of the resin layer at 25°C is 1000 MPa to 8000 MPa. In addition, Patent Document 2 describes an optical laminate having a thin glass with a thickness of 120 μm or less and a shock absorbing layer with a thickness of 5 μm or more arranged on one side of the thin glass, wherein the shock absorbing layer has a bending elastic modulus of 1000 MPa to 8000 MPa at 25°C. 1 ~10 15 Hz has a maximum value of tanδ. In addition, Patent Document 3 describes a cover member having a structure in which a glass plate having a thickness of 500 μm or less and a resin film are laminated via an adhesive layer. In addition, Patent Document 4 describes a substrate for a display element having an inorganic glass and a resin layer disposed on both sides of the inorganic glass.

[0004] However, regarding the resin composition for forming the resin layer for protecting thin glass, from the viewpoint of improving the impact resistance, the composition has not been sufficiently studied in the past, or a resin composition with insufficient impact resistance has been used, and further improvement of the impact resistance has been demanded.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-37207

[0008] Patent Document 2: International Publication No. 2018 / 190208

[0009] Patent Document 3: International Publication No. 2020 / 153259

[0010] Patent Document 4: Japanese Patent Application Publication No. 2008-107510 Summary of the invention

[0011] Problems to be solved by the invention

[0012] An object of the present invention is to provide a laminate having excellent impact resistance. Another object of the present invention is to provide an electronic device and a cover glass using the laminate, and a resin composition for forming a resin layer of the laminate.

[0013] Means for solving problems

[0014] The present disclosure 1 relates to a laminate (first laminate) comprising a thin plate glass having a thickness of 200 μm or less and a resin layer having a thickness of 5 μm or more and disposed on at least one side of the thin plate glass, wherein the fracture energy of the resin layer is 1 mJ / mm 3 and the storage modulus of the resin layer at 25° C. is 2500 MPa or less.

[0015] The present disclosure 2 is related with the laminated body of the present disclosure 1, wherein the Young's modulus of the resin layer is 50 MPa or more and 1500 MPa or less.

[0016] The present disclosure 3 relates to the laminated body of the present disclosure 1 or 2, wherein the storage modulus of the resin layer at 25° C. is 2000 MPa or less.

[0017] The present disclosure 4 relates to the laminated body of the present disclosure 1, 2 or 3, wherein the glass transition temperature of the resin layer is 100° C. or lower.

[0018] Present disclosure 5 relates to the laminated body of Present Disclosure 1, 2, 3 or 4, wherein the resin layer contains a polymer of a cationically curable resin.

[0019] Present disclosure 6 relates to the laminated body of present disclosure 5, wherein the cationically curable resin contains an epoxy group-containing compound and an oxetane group-containing compound.

[0020] Present Disclosure 7 relates to the laminated body of Present Disclosure 6, wherein the epoxy group-containing compound includes a hydrogenated bisphenol-type epoxy resin.

[0021] The present disclosure 8 relates to the laminated body of the present disclosure 7, wherein the hydrogenated bisphenol-type epoxy resin contains a hydrogenated bisphenol A skeleton.

[0022] The present disclosure 9 relates to the laminated body of the present disclosure 7 or 8, wherein the epoxy equivalent of the hydrogenated bisphenol-type epoxy resin is 100 or more and 2000 or less.

[0023] Present disclosure 10 relates to the laminated body of present disclosure 6, 7, 8 or 9, wherein the epoxy group-containing compound comprises an epoxy resin having a polyether skeleton.

[0024] The present disclosure 11 relates to the laminated body of the present disclosure 10, wherein the epoxy resin having a polyether skeleton is in a liquid state at 23°C.

[0025] Present Disclosure 12 relates to the laminated body of Present Disclosure 6, 7, 8, 9, 10 or 11, wherein the oxetane group-containing compound is monofunctional.

[0026] The present disclosure 13 relates to the laminated body of the present disclosure 5, 6, 7, 8, 9, 10, 11 or 12, wherein the cationic curable resin comprises a hydrogenated bisphenol-type epoxy resin, an epoxy resin having a polyether skeleton, and an oxetane group-containing compound.

[0027] The present disclosure 14 relates to the laminated body of the present disclosure 13, wherein, in the above-mentioned resin layer, the content of the hydrogenated bisphenol-type epoxy resin is greater than 20 weight % and less than 60 weight %, the content of the above-mentioned epoxy resin having a polyether skeleton is greater than 10 weight % and less than 20 weight %, and the content of the above-mentioned oxetane-containing compound is greater than 20 weight % and less than 60 weight %.

[0028] Disclosure 15 relates to the laminated body of Disclosure 1, which comprises: a first resin layer, which is arranged on one side of the thin plate glass and has a thickness of 5 μm or more; and a second resin layer, which is arranged on the side of the thin plate glass opposite to the first resin layer side and has a thickness of 5 μm or more, and the fracture energy of the first resin layer and the second resin layer are both 1 mJ / mm 3 The storage modulus at 25°C is 2500 MPa or less.

[0029] The present disclosure 16 is related with the laminated body of the present disclosure 15, wherein the Young's modulus of the first resin layer and the second resin layer are both 50 MPa or more and 1500 MPa or less.

[0030] Present disclosure 17 relates to the laminated body of present disclosure 15 or 16, wherein at least one of the first resin layer and the second resin layer has a thickness of 25 μm or less.

[0031] Present disclosure 18 relates to the laminated body of present disclosure 15, 16 or 17, wherein the glass transition temperature of at least one of the first resin layer and the second resin layer is 100° C. or lower.

[0032] The present disclosure 19 relates to the laminated body of the present disclosure 15, 16, 17 or 18, wherein at least one of the first resin layer and the second resin layer contains a polymer of a cation-curable resin.

[0033] The present disclosure 20 relates to a laminate (second laminate) comprising a thin plate glass having a thickness of 200 μm or less and a resin layer having a thickness of 5 μm or more and arranged on at least one side of the thin plate glass, wherein the resin layer has a Young's modulus of 50 MPa to 1500 MPa.

[0034] Disclosure 21 relates to the laminated body of Disclosure 20, wherein the fracture energy of the resin layer is 1 mJ / mm 3 above.

[0035] Disclosure 22 relates to the laminated body of Disclosure 20 or 21, wherein the storage modulus of the resin layer at 25° C. is 2500 MPa or less.

[0036] Disclosure 23 relates to the laminated body of Disclosure 20, 21 or 22, wherein the glass transition temperature of the resin layer is 100° C. or lower.

[0037] Disclosure 24 relates to the laminated body of Disclosure 20, 21, 22 or 23, wherein the resin layer contains a polymer of a cation-curable resin.

[0038] Disclosure 25 relates to the laminated body of Disclosure 24, wherein the cationically curable resin contains an epoxy group-containing compound and an oxetane group-containing compound.

[0039] Disclosure 26 relates to the laminated body of Disclosure 25, wherein the epoxy group-containing compound includes a hydrogenated bisphenol-type epoxy resin.

[0040] Disclosure 27 relates to the laminated body of Disclosure 26, wherein the hydrogenated bisphenol-type epoxy resin includes a hydrogenated bisphenol A skeleton.

[0041] Present Disclosure 28 relates to the laminated body of Present Disclosure 26 or 27, wherein the epoxy equivalent of the hydrogenated bisphenol-type epoxy resin is 100 or more and 2000 or less.

[0042] Disclosure 29 relates to the laminated body of Disclosure 25, 26, 27 or 28, wherein the epoxy group-containing compound comprises an epoxy resin having a polyether skeleton.

[0043] Disclosure 30 relates to the laminated body of Disclosure 29, wherein the epoxy resin having a polyether skeleton is in a liquid state at 23°C.

[0044] Disclosure 31 relates to the laminated body of Disclosure 25, 26, 27, 28, 29 or 30, wherein the oxetane group-containing compound is monofunctional.

[0045] Disclosure 32 relates to the laminated body of Disclosure 24, 25, 26, 27, 28, 29, 30 or 31, wherein the cationic curable resin comprises a hydrogenated bisphenol-type epoxy resin, an epoxy resin having a polyether skeleton and an oxetane group-containing compound.

[0046] The present disclosure 33 relates to a laminate of the present disclosure 32, wherein, in the above-mentioned resin layer, the content of the hydrogenated bisphenol-type epoxy resin is greater than 20 weight % and less than 60 weight %, the content of the above-mentioned epoxy resin having a polyether skeleton is greater than 10 weight % and less than 20 weight %, and the content of the above-mentioned oxetane-containing compound is greater than 20 weight % and less than 60 weight %.

[0047] Disclosure 34 of the present invention relates to a laminate of disclosure 20 of the present invention, comprising: a first resin layer, arranged on one side of the thin glass, and having a thickness of 5 μm or more; and a second resin layer, arranged on the side of the thin glass opposite to the first resin layer, and having a thickness of 5 μm or more, wherein the Young's modulus of the first resin layer and the second resin layer are both greater than 50 MPa and less than 1500 MPa.

[0048] The present disclosure 35 is related with the laminated body of the present disclosure 34, wherein the storage modulus of at least one of the first resin layer and the second resin layer at 25° C. is 3000 MPa or less.

[0049] Disclosure 36 relates to the laminated body of Disclosure 34 or 35, wherein the thickness of at least one of the first resin layer and the second resin layer is 25 μm or less.

[0050] Disclosure 37 relates to the laminated body of Disclosure 34, 35 or 36, wherein the glass transition temperature of at least one of the first resin layer and the second resin layer is 100° C. or lower.

[0051] Disclosure 38 relates to the laminated body of Disclosure 34, 35, 36 or 37, wherein at least one of the first resin layer and the second resin layer contains a polymer of a cation-curable resin.

[0052] Disclosure 39 relates to the laminated body of Disclosure 38, wherein the cationically curable resin contains an epoxy group-containing compound and an oxetane group-containing compound.

[0053] Disclosure 40 relates to the laminated body of Disclosure 39, wherein the epoxy group-containing compound includes a hydrogenated bisphenol-type epoxy resin.

[0054] Present disclosure 41 relates to the laminated body of present disclosure 40, wherein the hydrogenated bisphenol-type epoxy resin includes a hydrogenated bisphenol A skeleton.

[0055] Present disclosure 42 relates to the laminated body of present disclosure 40 or 41, wherein the epoxy equivalent of the hydrogenated bisphenol-type epoxy resin is 100 or more and 2000 or less.

[0056] Disclosure 43 relates to the laminated body of Disclosure 39, 40, 41 or 42, wherein the epoxy group-containing compound comprises an epoxy resin having a polyether skeleton.

[0057] Disclosure 44 relates to the laminated body of Disclosure 43, wherein the epoxy resin having a polyether skeleton is in a liquid state at 23°C.

[0058] Disclosure 45 relates to the laminated body of Disclosure 39, 40, 41, 42, 43 or 44, wherein the oxetane group-containing compound is monofunctional.

[0059] The present disclosure 46 relates to the laminated body of the present disclosure 38, 39, 40, 41, 42, 43, 44 or 45, wherein the above-mentioned cationic curable resin contains a hydrogenated bisphenol-type epoxy resin, an epoxy resin having a polyether skeleton and an oxetane group-containing compound.

[0060] The present disclosure 47 relates to a laminate of the present disclosure 46, wherein, in the resin layer of the polymer containing the above-mentioned cationic curable resin, the content of the hydrogenated bisphenol-type epoxy resin is greater than 20 weight % and less than 60 weight %, the content of the above-mentioned epoxy resin having a polyether skeleton is greater than 10 weight % and less than 20 weight %, and the content of the above-mentioned oxetane-containing compound is greater than 20 weight % and less than 60 weight %.

[0061] Present Disclosure 48 relates to an electronic device including the laminated body according to any one of Present Disclosures 1 to 47.

[0062] This disclosure 49 relates to a cover glass including the laminated body according to any one of this disclosure 1 to 47.

[0063] The present disclosure 50 relates to a resin composition for forming a resin layer of the laminated body according to any one of the present disclosures 1 to 47.

[0064] The present disclosure 51 relates to a resin composition comprising a hydrogenated bisphenol-type epoxy resin, an epoxy resin having a polyether skeleton, and an oxetane group-containing compound.

[0065] Present disclosure 52 relates to the resin composition of present disclosure 50 or 51, which is used for coating on a thin plate glass having a thickness of 200 μm or less.

[0066] Disclosure 53 relates to the resin composition of Disclosure 51 or 52, wherein the hydrogenated bisphenol-type epoxy resin comprises a hydrogenated bisphenol A skeleton.

[0067] Present disclosure 54 relates to the resin composition of present disclosure 51, 52 or 53, wherein the epoxy equivalent of the hydrogenated bisphenol-type epoxy resin is 100 or more and 2000 or less.

[0068] Disclosure 55 relates to the resin composition of Disclosure 51, 52, 53 or 54, wherein the epoxy resin having a polyether skeleton is liquid at 23°C.

[0069] Disclosure 56 relates to the resin composition of Disclosure 51, 52, 53, 54 or 55, wherein the oxetane group-containing compound is monofunctional.

[0070] Disclosure 57 relates to the resin composition of Disclosure 51, 52, 53, 54, 55 or 56, wherein the content of hydrogenated bisphenol-type epoxy resin is greater than 20 weight % and less than 60 weight %, the content of the above-mentioned epoxy resin having a polyether skeleton is greater than 10 weight % and less than 20 weight %, and the content of the above-mentioned oxetane-containing compound is greater than 20 weight % and less than 60 weight %.

[0071] Hereinafter, the present invention will be described in detail.

[0072] The present inventors studied the resin layer disposed on at least one side of the thin plate glass and found that the fracture energy was set to 1 mJ / mm 3 If the storage elastic modulus at 25° C. is set to 2500 MPa or less, sufficient impact resistance can be obtained.

[0073] The present inventors have studied the resin layer disposed on at least one side of the thin plate glass and found that sufficient impact resistance can be obtained by setting the Young's modulus to 50 MPa to 1500 MPa, focusing on the correlation between the Young's modulus of the resin layer and the impact resistance.

[0074] In addition, the inventors have studied how to improve the impact resistance of thin glass arranged on the display surface of electronic devices, etc. by laminating a resin layer on the surface thereof. As a result, it was found that by providing resin layers on both sides of the thin glass, the glass can be effectively prevented from scattering, and the impact resistance can be improved by adjusting the combination of the fracture energy and storage modulus of the first and second resin layers, or the Young's modulus to within a specific range.

[0075] Furthermore, the present inventors have found a resin composition suitable for forming a resin layer having a breaking energy, a storage elastic modulus at 25° C., and a Young's modulus adjusted within specific ranges.

[0076] As described above, the present inventors have completed the present invention.

[0077] The laminate of the present invention (hereinafter, matters common to the first laminate and the second laminate are also referred to as "the laminate of the present invention") comprises a thin plate glass having a thickness of 200 μm or less, and a resin layer having a thickness of 5 μm or more and arranged on at least one side of the thin plate glass. It is sufficient to provide at least one layer of the resin layer in the laminate of the present invention. For example, one or more layers of the resin layer may be arranged on one side of the thin plate glass, or one or more layers of the resin layer may be arranged on both sides. In addition, the laminate of the present invention may have other layers other than the thin plate glass and the resin layer. For example, the resin layer may be laminated with the thin plate glass via an adhesive layer, but it is preferably in direct contact with the thin plate glass without the aid of an adhesive layer. From the viewpoint of effectively utilizing the advantages of using a flexible thin plate glass, it is preferred that only one layer of the resin layer is arranged on one side of the thin plate glass, or one layer of the resin layer is arranged on both sides. When the resin layer is provided without an adhesive layer, a method of forming the resin layer by applying a resin composition that is a material of the resin layer onto the surface of the thin plate glass and curing the resin composition is preferably used.

[0078] In addition, the laminate of the present invention preferably has the thin plate glass or the resin layer disposed on the outermost surface. That is, the laminate of the present invention may have a structure in which the thin plate glass is disposed on the outermost surface and the resin layer is disposed thereunder, or may have a structure in which the resin layer is disposed on the outermost surface and the thin plate glass is disposed thereunder. Among them, from the viewpoint of taking into account both the scratch resistance of the glass and the improvement of the impact resistance brought about by the resin layer, it is particularly preferred to have a structure in which the thin plate glass is disposed on the outermost surface and the resin layer is disposed thereunder.

[0079] The resin layer preferably covers 80% or more of the area of ​​the thin-plate glass in a plan view, and more preferably covers the entire surface of the thin-plate glass.

[0080] The configurations of the first stack and the second stack are appropriately selected depending on the intended use. When the stack is disposed in front of a display device such as an organic electroluminescent display device, for example, Figure 1 The composition shown. Figure 1 Schematic cross-sectional view showing an example of the structure of the laminate of the present invention. Figure 1 In the embodiment, the laminate 10 includes a first resin layer 11 on one side (viewing side) of a thin plate glass 12 and a second resin layer 13 on the side (display device side) opposite to the first resin layer 11 of the thin plate glass 12, and can also be integrated with a polarizing plate 15 via an optically transparent adhesive (OCA) 14.

[0081] The above-mentioned thin plate glass is not particularly limited as long as it is plate-shaped and has a thickness of 200 μm or less. The composition of the above-mentioned thin plate glass can include, for example, soda-lime glass, boric acid glass, aluminosilicate glass, quartz glass, etc. In addition, according to the classification based on the alkali component, alkali-free glass and low-alkali glass can be mentioned. From the aspect of impact resistance, the above-mentioned thin plate glass is preferably a chemically strengthened glass that has been subjected to a chemical strengthening treatment. The chemically strengthened glass preferably has a compressive stress layer formed by a chemical strengthening treatment (ion exchange treatment) on the surface.

[0082] The thickness of the thin plate glass is 200 μm or less. By making the thickness of the thin plate glass 200 μm or less, the flexibility required for foldable electronic devices can be obtained. In addition, the thinner the thickness of the thin plate glass, the more significantly the improvement in impact resistance brought about by the resin layer is manifested. The thickness of the thin plate glass is preferably 150 μm or less, and more preferably 100 μm or less. In addition, the thickness of the thin plate glass is preferably 5 μm or more, more preferably 10 μm or more, further preferably 20 μm or more, and particularly preferably 30 μm or more. By making the thin plate glass have a certain thickness or more, flexibility and impact resistance can be taken into account.

[0083] The light transmittance of the thin plate glass at a wavelength of 550 nm is preferably 85% or more. The refractive index of the thin plate glass at a wavelength of 550 nm is preferably 1.4 to 1.65.

[0084] The density of the thin glass is preferably 2.3 g / cm 3 ~3.0g / cm 3 , more preferably 2.3 g / cm 3 ~2.7g / cm 3 .

[0085] The method for making the glass used for the above-mentioned thin plate glass expansion is not particularly limited. For example, a mixture containing main raw materials such as silicon dioxide and aluminum oxide, defoaming agents such as sodium sulfate and antimony oxide, and reducing agents such as carbon is melted at a temperature of 1400°C to 1600°C, formed into a thin plate, and then cooled to make it. As the thin plate forming method of the above-mentioned glass, for example, a flow hole down-drawing method, a melting method, a float method, etc. can be cited. In order to thin the glass or improve the smoothness, the glass formed into a plate by these methods can be chemically polished using a solvent such as hydrofluoric acid as needed.

[0086] In the case of chemically strengthened glass, a chemical strengthening treatment is performed. In the chemical strengthening treatment, ion exchange is performed on the surface of the glass to form a surface layer (compressive stress layer) in which compressive stress remains. Specifically, at a temperature below the glass transition temperature, alkali metal ions (typically Li ions or Na ions) with a small ionic radius present near the surface of the glass plate are replaced by alkali ions with a larger ionic radius (typically, Na ions or K ions for Li ions, and K ions for Na ions) through ion exchange. As a result, compressive stress remains on the surface of the glass, and the strength of the glass is improved.

[0087] As the thin plate glass, commercially available thin plate glass may be used as it is, or commercially available glass may be subjected to additional treatment such as grinding or etching so as to have a desired thickness and used.

[0088] <First laminate>

[0089] The fracture energy of the above resin layer is 1mJ / mm 3 By making the fracture energy of the above resin layer 1mJ / mm 3 The above mentioned properties can provide sufficient impact resistance to thin glass that is thinned to realize foldable electronic devices. The fracture energy is preferably 1.5 mJ / mm 3 More preferably, 2 mJ / mm 3 In addition, the upper limit of the fracture energy is not particularly limited, but from the viewpoint of ensuring other properties of the laminate, it is, for example, 50 mJ / mm 3 the following.

[0090] It should be noted that the above-mentioned fracture energy is measured in accordance with JIS K7113 "Tensile test method for plastics" using a test piece prepared according to the following steps. On a glass plate with a thickness of 0.7 mm, a demolding surface of a polyethylene terephthalate resin film that has been subjected to a demolding treatment is set as the upper surface, and a mold of a silicon wafer with a thickness of 0.5 mm punched into the shape of a dumbbell (SDK-400) is further set. The resin composition for forming the resin layer is poured into the dumbbell mold, and after the demolding surface of the polyethylene terephthalate resin film that has been subjected to a demolding treatment is covered with the resin liquid in a manner that does not involve bubbles, another glass plate is overlapped. Next, a wavelength of 365 nm and an illumination of 100 mW / cm 2 The UV LED was used as the light source, and the exposure time was 15 seconds through the glass plate, irradiating 1500mJ / cm 2of ultraviolet rays. Furthermore, turn it over while being clamped by the glass plates, and irradiate the same ultraviolet rays again from the back. Then, heat it in an oven at 80°C for 30 minutes to cure the resin, and take out the cured resin from the silicon wafer mold to make a test piece. The test piece was subjected to a tensile test using a tensile testing machine. The tensile test was carried out under the conditions of a chuck distance of 25 mm, a tensile speed of 50 mm / min, and a sampling interval of 20 μm until the test piece broke. Based on the measurement results obtained, a stress-strain curve with stress (unit: MPa) on the vertical axis and strain (unit: %) on the horizontal axis was prepared, and the area of ​​the portion surrounded by the stress-strain curve and the horizontal axis was obtained, thereby being able to calculate the fracture energy.

[0091] It should be noted that when the fracture energy of the resin layer is measured directly from the laminate, the resin layer is punched into a dumbbell shape (SDK-400) and used as the above test piece. Alternatively, the resin layer is dissolved in a solvent to prepare a resin liquid, which is then poured into the above dumbbell mold and the solvent is completely dried to prepare a test piece.

[0092] The Young's modulus of the resin layer is preferably 1500MPa or less. If the Young's modulus of the resin layer is 1500MPa or less, the resin layer can have moderate softness, so it is preferred to make a laminate having the flexibility required for realizing a foldable electronic device. In addition, when the glass breaks, the resin film is not easy to break at the same time, and an anti-scattering effect can also be obtained. The Young's modulus is more preferably 1300MPa or less, and further preferably 1200MPa or less. In addition, the lower limit of the Young's modulus is not particularly limited, and from the viewpoint of ensuring the impact resistance of the laminate, it is preferably 50MPa or more. Regarding the Young's modulus, it can be calculated by making a stress-strain curve in the same way as the measurement of the fracture energy, and finding the slope of the stress-strain curve when the strain is 0 to 10%.

[0093] The storage modulus of the resin layer at 25°C is 2500MPa or less. If the storage modulus of the resin layer is 2500MPa or less, sufficient impact resistance can be imparted to the thin glass. In addition, since the softness of the resin layer can be ensured, a laminate having the flexibility required for realizing a foldable electronic device can be made. The storage modulus is preferably 2000MPa or less, and more preferably 1800MPa or less. In addition, the lower limit of the storage modulus is not particularly limited, and from the viewpoint of ensuring the impact resistance of the laminate, for example, it is 100MPa or more.

[0094] It should be noted that, regarding the measurement of the storage modulus, two test pieces of the resin cured product prepared in the same manner as in the measurement of the fracture energy are overlapped to a thickness of 1 mm to prepare a measurement sample. The prepared measurement sample can be measured using a viscoelastic spectrometer (e.g., DVA-200 manufactured by IT Instrumentation and Control Co., Ltd.) under the conditions of 5°C / min and 1 Hz in a slow heating shear deformation mode at -50°C to 200°C, and the storage modulus at 25°C at this time can be obtained.

[0095] <Second laminate>

[0096] The Young's modulus of the resin layer is 50 MPa or more and 1500 MPa or less. By making the Young's modulus of the resin layer 50 MPa or more and 1500 MPa or less, it is possible to obtain a moderate flexibility for realizing a foldable electronic device, and it is possible to give sufficient impact resistance to the thin glass that is thinned to realize a foldable electronic device. The Young's modulus is preferably 1300 MPa or less, more preferably 1200 MPa or less, and preferably 80 MPa or more.

[0097] It should be noted that the measurement of the above Young's modulus is carried out in accordance with JIS K7113 "Tensile test method for plastics" using a test piece prepared according to the following steps. On a glass plate with a thickness of 0.7 mm, a demolding surface of a polyethylene terephthalate resin film that has been subjected to a demolding treatment is set as the upper surface, and a mold for a silicon wafer with a thickness of 0.5 mm punched out into the shape of a dumbbell (SDK-400) is further set. The resin composition for forming the resin layer is poured into the dumbbell mold, and after the demolding surface of the polyethylene terephthalate resin film that has been subjected to a demolding treatment is covered with the resin liquid in a manner that does not involve bubbles, another glass plate is overlapped. Next, a wavelength of 365 nm and an illumination of 100 mW / cm 2 The UV LED was used as the light source, and the exposure time was 15 seconds through the glass plate, irradiating 1500mJ / cm 2 of ultraviolet rays. Furthermore, turn it over while being sandwiched by the glass plates, and irradiate the same ultraviolet rays again from the back. Then, heat it in an oven at 80°C for 30 minutes to cure the resin, and take out the cured resin from the silicon wafer mold to make a test piece. The test piece was subjected to a tensile test using a tensile testing machine. The tensile test was carried out under the conditions of a chuck distance of 25 mm, a tensile speed of 50 mm / min, and a sampling interval of 20 μm until the test piece broke. Based on the measurement results obtained, a stress-strain curve with stress (unit: MPa) on the vertical axis and strain (unit: %) on the horizontal axis was prepared, and the slope of the stress-strain curve when the strain was 0-1% was obtained, from which the strain can be calculated.

[0098] It should be noted that when the Young's modulus of the resin layer is directly measured from the laminate, the resin layer is punched into a dumbbell shape (SDK-400) and used as the above test piece. Alternatively, the resin layer is dissolved in a solvent to prepare a resin liquid, which is then poured into the above dumbbell mold and the solvent is completely dried to prepare a test piece.

[0099] The fracture energy of the resin layer is preferably 1 mJ / mm 3 If the fracture energy of the above resin layer is 1mJ / mm 3 The fracture energy is preferably 1.5 mJ / mm 3 More preferably, 2 mJ / mm 3 In addition, the upper limit of the fracture energy is not particularly limited, but from the viewpoint of ensuring other properties of the laminate, it is, for example, 50 mJ / mm 3 The above-mentioned fracture energy can be calculated by preparing a stress-strain curve in the same manner as in the case of measuring the above-mentioned Young's modulus and obtaining the area of ​​the portion surrounded by the stress-strain curve and the horizontal axis.

[0100] The storage modulus of the resin layer at 25°C is preferably 2500 MPa or less. If the storage modulus of the resin layer is 2500 MPa or less, the softness of the resin layer can be ensured, so it is preferred to make a laminate having the flexibility required for realizing a foldable electronic device. The storage modulus is more preferably 2000 MPa or less, and further preferably 1800 MPa or less. In addition, the lower limit of the storage modulus is not particularly limited, and from the viewpoint of ensuring the impact resistance of the laminate, for example, it is 100 MPa or more.

[0101] It should be noted that, regarding the measurement of the storage modulus, two test pieces of the resin cured product prepared in the same manner as in the measurement of the fracture energy are overlapped to a thickness of 1 mm to prepare a measurement sample. The prepared measurement sample can be measured using a viscoelastic spectrometer (e.g., DVA-200 manufactured by IT Instrumentation and Control Co., Ltd.) under the conditions of 5°C / min and 1 Hz in a slow heating shear deformation mode at -50°C to 200°C for a dynamic viscoelastic spectrum, and the storage modulus at 20°C at this time can be obtained.

[0102] <First and second laminated bodies>

[0103] The elongation at break of the resin layer is preferably 5% or more. If the elongation at break of the resin layer is 5% or more, cracks and whitening are not easily generated in the bending durability test. The elongation at break of the resin layer is more preferably 7% or more. The upper limit of the elongation at break is not particularly limited, but is preferably 1000% or less from the viewpoint of ensuring the impact resistance of the laminate. The elongation at break can be subjected to a tensile test in the same manner as the measurement of the energy at break, using the value of the strain when the test piece breaks.

[0104] The fracture strength of the resin layer is preferably 5 MPa or more and 50 MPa or less. If the fracture strength of the resin layer is within the range of 5 MPa or more and 50 MPa or less, it is easy to impart sufficient impact resistance to thin glass. The fracture strength of the resin layer is more preferably 10 MPa or more and 40 MPa or less. The fracture strength can be measured by a tensile test in the same manner as the measurement of the fracture energy, using the value of the stress when the test piece is broken.

[0105] The glass transition temperature of the resin layer is preferably 100°C or less. If the glass transition temperature of the resin layer is 100°C or less, the softness of the resin layer can be ensured, so it is preferred in making a laminate having the flexibility required for realizing a foldable electronic device. The glass transition temperature is more preferably 80°C or less. In addition, the lower limit of the glass transition temperature is not particularly limited, and from the viewpoint of ensuring other properties of the laminate, it is, for example, 0°C or more. It should be noted that the glass transition temperature can be used to prepare a dynamic viscoelastic spectrum in the same way as in the case of the measurement of the storage modulus, using the temperature of the maximum value of the loss tangent.

[0106] The total light transmittance of the resin layer is preferably 80% or more. If the total light transmittance of the resin layer is 80% or more, the transparency of the resin layer can be ensured, so it is preferred to make a laminate having the transparency required for realizing a foldable display device (foldable display). The total light transmittance is more preferably 90% or more. The total light transmittance can be measured, for example, using HazeMeter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The total light transmittance is measured by a method based on JIS K 7361-1.

[0107] The thickness of the resin layer is 5 μm or more. By making the thickness of the resin layer 5 μm or more, the soft resin layer can be used to mitigate the impact, and sufficient impact resistance can be given to the thin glass that is thinned to achieve foldable electronic devices. The thickness of the resin layer is preferably 10 μm or more. In addition, the upper limit of the thickness of the resin layer is not particularly limited. From the perspective of ensuring the bendability of the laminate, it is preferably thinner than the thin plate glass. Specifically, it is preferably 100 μm or less, more preferably 50 μm or less, further preferably 30 μm or less, and particularly preferably 20 μm or less.

[0108] In addition, as a preferred embodiment of the first laminate and the second laminate, there can be mentioned a embodiment having a thin plate glass having a thickness of 200 μm or less, a first resin layer having a thickness of 5 μm or more and arranged on one side of the thin plate glass, and a second resin layer having a thickness of 5 μm or more and arranged on the side of the thin plate glass opposite to the first resin layer side. It is sufficient that at least one layer of the first resin layer and the second resin layer is provided in the first laminate and the second laminate. In addition, in the preferred embodiment, the first laminate and the second laminate may also have other layers besides the thin plate glass, the first resin layer and the second resin layer. For example, the first resin layer and the second resin layer may be laminated with the thin plate glass via an adhesive layer, but preferably, they are in direct contact with the thin plate glass without an adhesive layer. When the first resin layer and the second resin layer are provided without an adhesive layer, a method of forming the resin layer by applying a resin composition that is a material of the first resin layer and the second resin layer onto the surface of the thin plate glass and curing the resin composition is preferably used.

[0109] The first resin layer and the second resin layer preferably cover 80% or more of the area of ​​the thin-plate glass in a plan view, and more preferably cover the entire surface of the thin-plate glass.

[0110] <Characteristics of the first and second resin layers included in the first laminate>

[0111] In the first laminate, the first resin layer and the second resin layer preferably have a breaking energy of 1 mJ / mm 3 The above-mentioned fracture energy is 1 mJ / mm 3 The above-mentioned properties can provide sufficient impact resistance to thin glass that is thinned to realize foldable electronic devices. The fracture energy is more preferably 1.5 mJ / mm 3 More preferably, 2 mJ / mm 3In addition, the upper limit of the fracture energy is not particularly limited, but from the viewpoint of ensuring other properties of the laminate, it is, for example, 50 mJ / mm 3 Below. In addition, if the above-mentioned storage modulus is below 2500MPa, sufficient impact resistance can be given to thin glass. In addition, since the softness of the resin layer can be ensured, a laminate having the flexibility required for realizing a foldable electronic device can be made. The above-mentioned storage modulus is more preferably below 2000MPa, and further preferably below 1800MPa. In addition, the lower limit of the above-mentioned storage modulus is not particularly limited, and from the viewpoint of ensuring the impact resistance of the laminate, for example, it is above 100MPa.

[0112] The above-mentioned breaking energy can be measured in accordance with JIS K7113 "Tensile testing methods for plastics" using a test piece prepared according to the following procedure.

[0113] On a 0.7 mm thick glass plate, a release surface of a polyethylene terephthalate resin film that had been subjected to a release treatment was placed as the upper surface, and a 0.5 mm thick silicon wafer mold that was punched into a dumbbell shape (SDK-400) was further placed. The resin composition for forming the resin layer was poured into the dumbbell mold, and the release surface of the polyethylene terephthalate resin film that had been subjected to a release treatment was covered with the resin liquid in a manner that did not involve bubbles, and then another glass plate was overlapped. Next, a wavelength of 365 nm and an illumination of 100 mW / cm 2 The UV LED was used as the light source, and the exposure time was 15 seconds through the glass plate, irradiating 1500mJ / cm 2 of ultraviolet rays. Furthermore, turn it over while being clamped by the glass plates, and irradiate the same ultraviolet rays again from the back. Then, heat it in an oven at 80°C for 30 minutes to cure the resin, and take out the cured resin from the silicon wafer mold to make a test piece. The test piece was subjected to a tensile test using a tensile testing machine. The tensile test was carried out under the conditions of a chuck distance of 25 mm, a tensile speed of 50 mm / min, and a sampling interval of 20 μm until the test piece broke. Based on the measurement results obtained, a stress-strain curve with stress (unit: MPa) on the vertical axis and strain (unit: %) on the horizontal axis was prepared, and the area of ​​the portion surrounded by the stress-strain curve and the horizontal axis was obtained, thereby being able to calculate the fracture energy.

[0114] It should be noted that when the fracture energy of the resin layer is measured directly from the laminate, the resin layer is punched into a dumbbell shape (SDK-400) and used as the above test piece. Alternatively, the resin layer is dissolved in a solvent to prepare a resin liquid, which is then poured into the above dumbbell mold and the solvent is completely dried to prepare a test piece.

[0115] In addition, in the measurement of the storage modulus, a die for a 0.5 mm thick silicon wafer punched into a rectangular shape of 5 mm in width and 50 mm in length was used instead of a die for a 0.5 mm thick silicon wafer punched into a dumbbell shape (SDK-400), and the measurement sample was prepared in the same manner as in the measurement of the fracture energy. The prepared measurement sample can be measured for a dynamic viscoelastic spectrum at -50°C to 200°C under the conditions of 5°C / min and 1 Hz in a slow heating shear deformation mode using a viscoelastic spectrometer (e.g., DVA-200 manufactured by IT Measurement and Control Co., Ltd.), and the storage modulus at 25°C at this time can be obtained.

[0116] The Young's modulus of the first resin layer and the second resin layer is preferably 1500MPa or less. If the Young's modulus is 1500MPa or less, the first resin layer and the second resin layer can have moderate softness, so it is preferred to make a laminate having the flexibility required for realizing a foldable electronic device. In addition, when the glass breaks, the resin layer is not easy to break at the same time, and an anti-scattering effect can also be obtained. The Young's modulus is more preferably 1400MPa or less, and further preferably 1300MPa or less. In addition, the lower limit of the Young's modulus is not particularly limited, and from the viewpoint of ensuring the impact resistance of the laminate, it is preferably 50MPa or more. Regarding the Young's modulus, it can be calculated by making a stress-strain curve in the same way as the measurement of the fracture energy, and finding the slope of the stress-strain curve when the strain is 0 to 10%.

[0117] <Characteristics of the first and second resin layers included in the second laminate>

[0118] In the second laminate, the first resin layer and the second resin layer preferably have a Young's modulus of 50 MPa or more and 1500 MPa or less. By making the Young's modulus 50 MPa or more and 1500 MPa or less, it is possible to obtain a moderate flexibility for realizing a foldable electronic device, and it is possible to give sufficient impact resistance to the thin glass that is thinned to realize a foldable electronic device. The Young's modulus is more preferably 1400 MPa or less, further preferably 1300 MPa or less, and more preferably 80 MPa or more.

[0119] The breaking energy of each of the first resin layer and the second resin layer is preferably 1 mJ / mm 3 If the above fracture energy is 1mJ / mm 3 The fracture energy is preferably 1.5 mJ / mm 3 More preferably, 2 mJ / mm 3In addition, the upper limit of the fracture energy is not particularly limited, but from the viewpoint of ensuring other properties of the laminate, it is, for example, 50 mJ / mm 3 the following.

[0120] The storage modulus of at least one of the first resin layer and the second resin layer at 25°C is preferably 3000MPa or less, more preferably 2500MPa or less, further preferably 2000MPa or less, particularly preferably 1800MPa or less, and particularly preferably 1500MPa or less. By making the storage modulus within the above range, the flexibility of the resin layer can be improved, so it is preferred to make a laminate having the flexibility required for realizing a foldable electronic device. In addition, the lower limit of the storage modulus is not particularly limited. From the perspective of ensuring the impact resistance of the laminate, it is preferably 10MPa or more, more preferably 100MPa or more, and further preferably 500MPa or more. From the perspective of improving the bending property of the laminate, the storage modulus of the first resin layer and the second resin layer at 25°C is preferably 2500MPa or less. From the perspective of ensuring the impact resistance of the laminate, the storage modulus of the first resin layer and the second resin layer at 25°C is preferably 100MPa or more.

[0121] <Characteristics of the first and second resin layers common to the first and second laminates>

[0122] The first resin layer and the second resin layer each preferably have an elongation at break of 5% or more. If the elongation at break is 5% or more, cracks and whitening are not easily generated in the bending durability test. The elongation at break is more preferably 7% or more. The upper limit of the elongation at break is not particularly limited, but is preferably 1000% or less from the viewpoint of ensuring the impact resistance of the laminate. The elongation at break can be subjected to a tensile test in the same manner as the determination of the energy at break, using the value of the strain when the test piece breaks.

[0123] The first resin layer and the second resin layer each preferably have a fracture strength of 5 MPa or more and 50 MPa or less. If the fracture strength is within the range of 5 MPa or more and 50 MPa or less, it is easy to impart sufficient impact resistance to thin glass. The fracture strength is more preferably 10 MPa or more and 40 MPa or less. The fracture strength can be measured by a tensile test in the same manner as the measurement of the fracture energy, using the value of the stress when the test piece is broken.

[0124] The first resin layer and the second resin layer each preferably have a glass transition temperature of 100°C or less, and at least one of the first resin layer and the second resin layer preferably has a glass transition temperature of 100°C or less. If the glass transition temperature of the resin layer is below 100°C, the softness of the resin layer can be ensured, and therefore it is preferred in making a laminate having the flexibility required for realizing a foldable electronic device. The glass transition temperature is more preferably below 80°C, and further preferably below 60°C. In addition, the lower limit of the glass transition temperature is not particularly limited, and from the viewpoint of ensuring other characteristics of the laminate, it is, for example, above 0°C. It should be noted that the glass transition temperature can be prepared in a dynamic viscoelastic spectrum in the same way as in the case of measuring the storage modulus, and the temperature of the maximum value of the loss tangent is used.

[0125] The first resin layer and the second resin layer each preferably have a total light transmittance of 80% or more. If the total light transmittance of the resin layer is 80% or more, the transparency of the resin layer can be ensured, and therefore, it is preferred to prepare a laminate having the transparency required for realizing a foldable display device (foldable display). The total light transmittance is more preferably 90% or more. The total light transmittance can be measured, for example, using HazeMeter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The total light transmittance is measured by a method based on JIS K 7361-1.

[0126] The thickness of the first resin layer and the second resin layer is preferably 5 μm or more, respectively. By making the thickness of the resin layer 5 μm or more, the soft resin layer can be used to mitigate the impact, and sufficient impact resistance can be given to the thin glass that is thinned to realize a foldable electronic device. The thickness of the first resin layer and the second resin layer is more preferably 10 μm or more. In addition, the upper limit of the thickness of the first resin layer and the second resin layer is not particularly limited. From the viewpoint of ensuring the bendability of the laminate, it is preferably thinner than thin plate glass. Specifically, it is preferably 100 μm or less, more preferably 50 μm or less, further preferably 30 μm or less, particularly preferably 25 μm or less, and most preferably 20 μm or less. From the viewpoint of ensuring the bendability of the laminate, it is preferred that the thickness of at least one of the first resin layer and the second resin layer is 25 μm or less.

[0127] Hereinafter, each material which can be used for the said resin layer, the said 1st resin layer, and the said 2nd resin layer is demonstrated.

[0128] The resin composition used to form the resin layer, the first resin layer, and the second resin layer is not particularly limited as long as the properties of the resin layer obtained after curing can be adjusted to within a desired range. For example, from the perspective of excellent adhesion to glass, a resin composition containing a cationically curable resin is preferably used. Preferably, at least one of the first resin layer and the second resin layer contains a polymer of a cationically curable resin, and more preferably, both the first resin layer and the second resin layer contain a polymer of a cationically curable resin.

[0129] The cationically curable resin is not particularly limited as long as it is a compound having at least one cationically polymerizable functional group in the molecule and having high cation polymerizability.

[0130] As the above-mentioned cationic polymerizable functional group, for example, epoxy group, oxetane group, vinyl ether group, episulfide group, ethyleneimine group, etc. can be cited. Among them, the above-mentioned cationic curable resin preferably includes at least one resin selected from epoxy resin (compound containing epoxy group), oxetane resin (compound containing oxetane group), and vinyl ether resin (compound containing vinyl ether group), and more preferably includes epoxy resin (compound containing epoxy group) and oxetane resin (compound containing oxetane group). Epoxy resin and oxetane resin have excellent adhesion to the above-mentioned thin plate glass, so when the laminated body of the present invention is repeatedly bent, it is possible to suppress the peeling of the resin layer.

[0131] The epoxy resin (compound containing an epoxy group) is not particularly limited, and examples thereof include: bisphenol-type epoxy resins such as bisphenol A type, bisphenol F type, bisphenol AD ​​type and bisphenol S type; novolac-type epoxy resins such as phenol novolac type and cresol novolac type; aromatic epoxy resins such as resorcinol-type epoxy resins and trisphenol methane triglycidyl ether; alicyclic epoxy resins; naphthalene-type epoxy resins; fluorene-type epoxy resins; dicyclopentadiene-type epoxy resins; polyether-modified epoxy resins such as epoxy resins having a polyether skeleton; NBR-modified epoxy resins; CTBN-modified epoxy resins; and hydrogenated products thereof. Among them, hydrogenated bisphenol epoxy resins and epoxy resins having a polyether skeleton are preferably used. These epoxy resins may be used alone or in combination of two or more.

[0132] The hydrogenated bisphenol epoxy resin is preferably a hydrogenated bisphenol A epoxy resin containing a hydrogenated bisphenol A skeleton. The hydrogenated bisphenol epoxy resin may be a multimer such as a dimer. The epoxy equivalent of the hydrogenated bisphenol epoxy resin is preferably greater than 100 and less than 2000. By making the epoxy equivalent greater than 100 and less than 2000, the crosslinking density of the epoxy resin is controlled within a preferred range, and the impact resistance can be further improved. The epoxy equivalent is defined as "the mass of the resin containing 1 equivalent of epoxy group" and is measured by a method according to JIS K7236.

[0133] Examples of the alicyclic epoxy resin include 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, ε-caprolactone-modified 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, bis(3,4-epoxycyclohexyl)adipate, 1,2-epoxy-4-vinylcyclohexane, 1,4-cyclohexanedimethanol diglycidyl ether, oxiranyl divinylcyclohexane, diepoxyvinylcyclohexane, 1,2,4-triepoxyethylcyclohexane, limonene dioxide, and alicyclic epoxy group-containing silicone oligomers. These alicyclic epoxy resins may be used alone or in combination of two or more.

[0134] The epoxy resin may be a liquid epoxy resin at room temperature (23° C.), or a solid epoxy resin at room temperature, or a combination thereof may be used as appropriate. The epoxy resin preferably includes at least one epoxy resin that is liquid at room temperature, for example, a hydrogenated bisphenol-type epoxy resin that is liquid at room temperature, or an epoxy resin having a polyether skeleton that is liquid at room temperature.

[0135] Examples of the epoxy resin that is liquid at room temperature include polyether skeleton epoxy resins such as "jER YX7400" and "jER YX7400N" (all manufactured by Mitsubishi Chemical Co., Ltd.); bisphenol A type epoxy resins such as "EPICLON 840", "EPICLON 840-S", "EPICLON 850", "EPICLON 850-S", and "EPICLON EXA-850CRP" (all manufactured by DIC Corporation); bisphenol F type epoxy resins such as "EPICLON 830", "EPICLON 830-S", "EPICLON EXA-830CRP", and "EPICLON EXA-830LVP" (all manufactured by DIC Corporation) and "jER 806H" (manufactured by Mitsubishi Chemical Co., Ltd.); "EPICLON HP-4032", "EPICLON HP-4032D (all manufactured by DIC) and other naphthalene-based epoxy resins; "jERYX8000", "jER YX8034", "jER YX8040" (all manufactured by Mitsubishi Chemical), "EPICLONEXA-7015" (manufactured by DIC), "EX-252" (manufactured by Nagase ChemteX) and other hydrogenated bisphenol A-based epoxy resins; "EX-201" (manufactured by Nagase ChemteX) and other resorcinol-based epoxy resins; "CELLOXIDE 2081", "CELLOXIDE2021P", "CELLOXIDE 2000", "CELLOXIDE 3000", "CELLOXIDE 8000", "CELLOXIDE 8010", "EHPE3150" (all manufactured by Daicel), "TTA21" (Jiangsu Alicyclic epoxy resins such as “X-22-169AS” (manufactured by TetraChem Co., Ltd.), “RIKARESINDME-100” (manufactured by Shin Nippon Chemical Co., Ltd.), “X-40-2670”, “X-22-169AS”, and “X-22-169B” (manufactured by Shin-Etsu Chemical Co., Ltd.) are available as commercial products.

[0136] As the epoxy resin that is solid at room temperature, for example, bisphenol A type epoxy resins such as "EPICLON 860", "EPICLON 10550", and "EPICLON 1055" (all manufactured by DIC Corporation); bisphenol F type epoxy resins such as "jER 4005P" (manufactured by Mitsubishi Chemical Corporation); bisphenol S type epoxy resins such as "EPICLON EXA-1514" (manufactured by DIC Corporation); naphthalene type epoxy resins such as "EPICLON HP-4700", "EPICLON HP-4710", and "EPICLON HP-4770" (all manufactured by DIC Corporation); dicyclopentadiene type epoxy resins such as "EPICLON HP-7200 series" (manufactured by DIC Corporation); cresol novolac type epoxy resins such as "EPICLON HP-5000" and "EPICLON EXA-9900" (all manufactured by DIC Corporation), etc. can be obtained as commercial products.

[0137] The oxetane resin (oxetane group-containing compound) as the cationic curable resin is not particularly limited, and examples thereof include 3-ethyl-3-[(2-ethylhexyloxy)methyl]oxetane, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis([(3-ethyl-3-oxetane)methoxy]methyl)benzene, 3-ethyl-3-(phenoxymethyl)oxetane, bis[(3-ethyloxetane-3-yl)methyl]ether, 3-ethyl-3-([3-(triethoxysilyl)propoxy]methyl)oxetane, and oxetane silsesquioxane. As the oxetane resin, a monofunctional oxetane resin is preferably used. As the above-mentioned oxetane resin, for example, "ETRENACOLL EHO" (manufactured by Ube Industries, Ltd.), "ARON OXETANE OXT-101", "ARON OXETANE OXT-121", "ARON OXETANE OXT-211", "ARON OXETANE OXT-221", "ARON OXETANE OXT-610" (all manufactured by Toagosei Co., Ltd.) and the like are available as commercial products. These may be used alone or in combination of two or more.

[0138] The vinyl ether resin (vinyl ether group-containing compound) as the cationic curable resin is not particularly limited, and examples thereof include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, allyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, isopentyl vinyl ether, tert-pentyl vinyl ether, n-hexyl vinyl ether, isohexyl vinyl ether, 2-ethylhexyl vinyl ether, n-heptyl vinyl ether, n-octyl vinyl ether, nonyl vinyl ether, decyl vinyl ether, dodecyl vinyl ether, hexadecyl vinyl ether, octadecyl vinyl ether, Ethoxymethyl vinyl ether, 2-methoxyethyl vinyl ether, 2-ethoxyethyl vinyl ether, 2-butoxyethyl vinyl ether, acetoxymethyl vinyl ether, 2-acetoxyethyl vinyl ether, 3-acetoxypropyl vinyl ether, 4-acetoxybutyl vinyl ether, 4-ethoxybutyl vinyl ether, 2-(2-methoxyethoxy)ethyl vinyl ether, 3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, diethylene glycol monovinyl ether, diethylene glycol methyl vinyl ether, diethylene glycol ethyl vinyl ether, triethylene glycol monovinyl ether, tetraethylene glycol Monovinyl ether, polyethylene glycol monovinyl ether, propylene glycol monovinyl ether, dipropylene glycol monovinyl ether, tripropylene glycol monovinyl ether, polypropylene glycol monovinyl ether, 4-hydroxycyclohexyl vinyl ether, cyclohexyl dimethanol monovinyl ether, trimethylolpropane monovinyl ether, ethylene oxide added trimethylolpropane monovinyl ether, pentaerythritol monovinyl ether, ethylene oxide added pentaerythritol monovinyl ether, cyclohexyl vinyl ether, cyclohexyl methyl vinyl ether, cyclohexyl ethyl vinyl ether, menthyl vinyl ether, tetrahydrofurfuryl vinyl ether, norbornene vinyl ether, 1-adamantyl vinyl ether, 2-adamantyl vinyl ether, phenylethylene ethyl vinyl ether, benzyl vinyl ether, 1-naphthyl vinyl ether, 2-naphthyl vinyl ether, glycidyl vinyl ether, diethylene glycol ethyl vinyl ether, triethylene glycol methyl vinyl ether, divinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, tetraethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, tripropylene glycol divinyl ether, polypropylene glycol divinyl ether, butanediol divinyl ether, neopentyl glycol divinyl ether, hexanediol divinyl ether, nonanediol divinyl ether, hydroquinone divinyl ether, 1,4-cyclohexanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, trimethylolpropane divinyl ether, ethylene oxide added trimethylolpropane divinyl ether, pentaerythritol divinyl ether, ethylene oxide added pentaerythritol divinyl ether, trimethylolpropane trivinyl ether, ethylene oxide added trimethylolpropane trivinyl ether, pentaerythritol trivinyl ether, ethylene oxide added pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, ethylene oxide added pentaerythritol tetravinyl ether, ditrimethylolpropane tetravinyl ether, dipentaerythritol hexavinyl ether, etc. These may be used alone or in combination of two or more. ,

[0139] The cationically curable resin is preferably a cationically curable resin comprising a hydrogenated bisphenol epoxy resin, an epoxy resin having a polyether skeleton, and an oxetane group-containing compound. Such a cationically curable resin can provide particularly excellent impact resistance, and thus can also provide a good result in the evaluation of anti-scattering properties based on a pen drop test.

[0140] The content of the hydrogenated bisphenol epoxy resin is not particularly limited, but is preferably 20 wt % or more, more preferably 40 wt % or more, and preferably 70 wt % or less, more preferably 50 wt % or less, relative to the total amount of the resin layer containing the polymer of the cationically curable resin.

[0141] The content of the epoxy resin having a polyether skeleton is not particularly limited, but is preferably 10 wt % or more, more preferably 12 wt % or more, preferably 40 wt % or less, more preferably 30 wt % or less, and further preferably 20 wt % or less, relative to the total amount of the resin layer containing the polymer of the cationic curable resin.

[0142] The content of the above-mentioned oxetane group-containing compound is not particularly limited, but is preferably 10 wt % or more, more preferably 20 wt % or more, preferably 70 wt % or less, more preferably 60 wt % or less, and further preferably 50 wt % or less, relative to the total amount of the resin layer containing the polymer of the above-mentioned cationic curable resin.

[0143] Preferably, in the resin layer comprising the polymer of the above-mentioned cationic curable resin, the content of the above-mentioned hydrogenated bisphenol-type epoxy resin is 20% by weight or more and 60% by weight or less, the content of the above-mentioned epoxy resin having a polyether skeleton is 10% by weight or more and 20% by weight or less, and the content of the above-mentioned oxetane group-containing compound is 20% by weight or more and 60% by weight or less.

[0144] The resin composition preferably contains a polymerization initiator. The polymerization initiator may be a photopolymerization initiator or a thermal polymerization initiator. Examples of the photopolymerization initiator include diphenyl iodonium, 4-methoxydiphenyl iodonium, bis(4-methylphenyl) iodonium, bis(4-tert-butylphenyl) iodonium, bis(dodecylphenyl) iodonium, diphenyl-4-thiophenoxyphenylsulfonium, bis[4-(diphenylsulfonium)-phenyl] sulfide, bis[4-(bis(4-(2-hydroxyethyl)phenyl)sulfonium)-phenyl] sulfide, η5-2,4-(cyclopentadienyl)[1,2,3,4,5,6-η-(methylethyl)phenyl]-iron (1+) and anions such as tetrafluoroborate, hexafluorophosphate, triphenyl hexafluorophosphate, and hexafluoroarsenate. Examples of the thermal polymerization initiator include imidazoles, quaternary ammonium salts, phosphorus compounds, amines, phosphines, phosphonium salts, bicyclic amidines and their salts, acid anhydrides, linear phenolic resins obtained by condensation reaction of phenol, cresol, xylenol, resorcinol, etc. with formaldehyde, liquid polythiol, polythioethers, and other polymercapto resins, amides, etc. These polymerization initiators may be used alone or in combination of two or more.

[0145] Relative to 100 parts by weight of the above-mentioned cation curable resin, the preferred lower limit of the content of the above-mentioned polymerization initiator is 0.1 parts by weight, and the preferred upper limit is 10 parts by weight. If the content of the above-mentioned polymerization initiator is less than 0.1 parts by weight, cationic polymerization may not be fully carried out sometimes, or the curing reaction may become too slow. If the content of the above-mentioned polymerization initiator exceeds 10 parts by weight, the curing reaction of the resin composition may become too fast, and workability may be reduced sometimes, or the composition of the obtained resin layer may become uneven. The more preferred lower limit of the content of the above-mentioned polymerization initiator is 0.5 parts by weight, and the more preferred upper limit is 5 parts by weight.

[0146] The resin composition may further contain various known additives such as a solvent, a viscosity modifier, a surface modifier (surfactant, leveling agent), a plasticizer, a silane coupling agent, a tackifier, a sensitizer, a thermosetting agent, a crosslinking agent, a curing retarder, an antioxidant, a storage stabilizer, a dispersant, and a filler within a range not hindering the purpose of the present invention.

[0147] There are no particular limitations on the method for preparing the resin composition, and examples thereof include a method of mixing a curable resin, a polymerization initiator, and additives added as required using a mixer, etc. Examples of the mixer include a homodispersor, a homomixer, a universal mixer, a planetary mixer, a kneader, and a three-roll mill.

[0148] The formation method of the resin layer, the first resin layer and the second resin layer is not particularly limited, and they can be formed, for example, by applying a resin composition on the surface of the thin glass and curing it by light irradiation, heating, etc. The coating method of the resin composition is not particularly limited, and for example, screen printing, die coating printing, offset printing, gravure printing, inkjet printing, etc. can be used.

[0149] In addition, an electronic device having the laminate of the present invention is also one of the present invention. As the electronic device of the present invention, a foldable electronic device (foldable electronic device) is suitable, wherein a foldable display device (foldable display) is suitable. Specifically, for example, portable display terminals such as smart phones, e-books, and tablet PCs can be cited. In a display device having the first laminate or the second laminate, it is preferred that the first resin layer is arranged on the viewing side and the second resin layer is arranged on the display device side.

[0150] The cover glass of the present invention is also one of the present invention. The cover glass of the present invention is preferably a protective glass arranged to cover an object to be protected, and more preferably the object to be protected is a display cover glass of a display device.

[0151] The resin composition for forming the resin layer of the laminate of the present invention is also one of the present invention. The resin composition of the present invention can exhibit excellent impact resistance after curing and is suitable for forming a thin film for protecting adherends such as glass.

[0152] The composition of the resin composition of the present invention is the same as that of the resin composition for forming the above-mentioned resin layer, the above-mentioned first resin layer, and the above-mentioned second resin layer.

[0153] The resin composition of the present invention preferably comprises a hydrogenated bisphenol epoxy resin, an epoxy resin having a polyether skeleton, and an oxetane-containing compound. Such a resin composition can provide particularly excellent impact resistance, and thus good results are obtained even in the evaluation of anti-scattering properties based on a pen drop test.

[0154] The hydrogenated bisphenol epoxy resin is preferably a hydrogenated bisphenol A epoxy resin containing a hydrogenated bisphenol A skeleton. The hydrogenated bisphenol epoxy resin may be a multimer such as a dimer. The epoxide equivalent of the hydrogenated bisphenol epoxy resin is preferably 100 or more and 2000 or less. The hydrogenated bisphenol epoxy resin is preferably a substance that is liquid at room temperature (23° C.). The hydrogenated bisphenol epoxy resin may be used alone or in combination of two or more.

[0155] The epoxy resin having a polyether skeleton is preferably a liquid at room temperature (23° C.) The epoxy resin having a polyether skeleton may be used alone or in combination of two or more.

[0156] As the oxetane group-containing compound (oxetane resin), a monofunctional oxetane group-containing compound is preferably used. The oxetane group-containing compound may be used alone or in combination of two or more.

[0157] The content of the hydrogenated bisphenol epoxy resin is not particularly limited, but is preferably 20 wt % or more, more preferably 40 wt % or more, and preferably 70 wt % or less, more preferably 50 wt % or less, based on the total amount of the resin composition of the present invention.

[0158] The content of the epoxy resin having a polyether skeleton is not particularly limited, but is preferably 10 wt % or more, more preferably 12 wt % or more, preferably 40 wt % or less, more preferably 30 wt % or less, and further preferably 20 wt % or less, relative to the total amount of the resin composition of the present invention.

[0159] The content of the oxetane group-containing compound is not particularly limited, but is preferably 10 wt % or more, more preferably 20 wt % or more, preferably 70 wt % or less, more preferably 60 wt % or less, and further preferably 50 wt % or less, relative to the total amount of the resin composition of the present invention.

[0160] Preferably, the content of the hydrogenated bisphenol-type epoxy resin in the resin composition of the present invention is 20% by weight or more and 60% by weight or less, the content of the epoxy resin having a polyether skeleton is 10% by weight or more and 20% by weight or less, and the content of the oxetane-containing compound is 20% by weight or more and 60% by weight or less.

[0161] The resin composition is preferably a resin composition for coating on a thin plate glass having a thickness of 200 μm or less.

[0162] From the viewpoint of coating properties, the resin composition may contain a solvent. As the solvent, from the viewpoint of coating properties, storage stability, etc., a non-polar solvent having a boiling point of 200°C or less or an aprotic polar solvent having a boiling point of 200°C or less is preferred. Examples of the non-polar solvent having a boiling point of 200°C or less or an aprotic polar solvent having a boiling point of 200°C or less include ketone solvents, ester solvents, hydrocarbon solvents, halogen solvents, ether solvents, nitrogen-containing solvents, etc. From the viewpoint of coating liquid stability, coating film uniformity, drying efficiency, etc., the boiling point of the non-polar solvent or aprotic polar solvent is more preferably in the range of 80°C to 180°C.

[0163] The resin composition uses an E-type viscometer, and the viscosity at 25°C is preferably 1 to 1000 mPa·s. The more preferred range of the above viscosity is adjusted according to the coating method. For example, in coating using an inkjet method, it is preferably in the range of 5 to 50 mPa·s, in coating using a slit coating method, it is preferably in the range of 10 to 100 mPa·s, and in coating using a roller coating method or an offset printing method, it is preferably in the range of 100 to 1000 mPa·s. On the other hand, if the viscosity exceeds 1000 mPa·s, there is a tendency that the leveling property of the coating liquid is reduced and the uniformity of the thickness of the coating film is reduced.

[0164] The viscosity can be measured, for example, by using VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) as an E-type viscometer and using a cone plate of CP1 at a rotation speed of 1 to 100 rpm appropriately selected from the optimum torque number in each viscosity range.

[0165] Effects of the Invention

[0166] According to the present invention, a laminate having excellent impact resistance can be provided. In addition, according to the present invention, an electronic device and a cover glass using the laminate, and a resin composition for forming a resin layer of the laminate can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0167] Figure 1 This is a schematic cross-sectional view showing an example of the structure of the laminated body of the present invention. DETAILED DESCRIPTION

[0168] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0169] (Examples 1 to 12, Comparative Examples 1 to 3)

[0170] The curable resin shown in (1), the initiator shown in (2), and the surface modifier shown in (3) were stirred and mixed according to the mixing ratio described in Table 1 to obtain a resin composition. The obtained resin composition was diluted with propylene glycol monomethyl ether acetate as a solvent to adjust the viscosity, and was applied on a thin plate glass with a thickness of 50 μm so that the thickness after drying would be 10 μm. The obtained coating film was dried at a temperature of 100°C for 15 minutes and then irradiated with an amount of 1500 mJ / cm 2 The glass was cured by irradiating with ultraviolet light having a wavelength of 365 nm and further heating at 80° C. for 30 minutes. As a result, a laminated body in which a resin layer composed of a cured resin was formed on one side of the thin plate glass was obtained.

[0171] (1) Curable resin

[0172] ·EPICLON EXA-830LVP (a mixture of bisphenol F type liquid epoxy resin and bisphenol A type liquid epoxy resin, manufactured by DIC Corporation)

[0173] ·jER YX7400 (polyether skeleton liquid epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd.)

[0174] ·jER 4005P (bisphenol F type solid epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd.)

[0175] ·jER 806H (bisphenol F type liquid epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd.)

[0176] ·jER YX8000 (hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent 192-220)

[0177] ·jER YX8034 (hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent 250-360)

[0178] ·jER YX8040 (hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent 900-1500)

[0179] CELLOXIDE 2021P (3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, manufactured by Daicel)

[0180] ETRENACOLL EHO (3-ethyl-3-hydroxymethyloxetane, manufactured by Ube Industries, Ltd.)

[0181] (2) Initiator

[0182] ·CPI-210S (triarylsulfonium salt-type photocationic polymerization initiator, manufactured by San-Apro)

[0183] (3) Surface modifier

[0184] ·JAR-33 (organic modified polysiloxane, manufactured by JUJO CHEMICAL)

[0185] (Comparative Example 4)

[0186] As the thin plate glass of Comparative Example 4, a thin plate glass having a thickness of 50 μm and the same as in Examples 1 to 5 and Comparative Examples 1 to 3 but without a resin layer formed on the surface was used.

[0187] <Physical property measurement>

[0188] The physical properties of the cured resins produced using the resin compositions of Examples 1 to 12 and Comparative Examples 1 to 3 were measured by the following methods.

[0189] (Storage modulus and glass transition temperature)

[0190] The test piece of the resin cured product was laminated to a thickness of 1 mm to prepare a measurement sample. For the prepared measurement sample, a viscoelastic spectrometer (manufactured by IT Measurement and Control Co., Ltd., DVA-200) was used to measure the dynamic viscoelastic spectrum from -50°C to 200°C under the conditions of 5°C / min and 1Hz in the slow heating shear deformation mode. The storage modulus at 25°C was calculated from the obtained dynamic viscoelastic spectrum. In addition, the temperature of the maximum value of the loss tangent was taken as the glass transition temperature Tg (°C).

[0191] (Young's modulus, elongation at break, breaking strength, breaking energy)

[0192] According to JIS K7113 "Tensile Test Method for Plastics", a test piece of a resin cured product with a thickness of 0.5 mm and molded into a dumbbell sample (SDK-400) was made, and a tensile test was carried out using a tensile testing machine. The tensile test was carried out under the conditions of a distance between chucks of 20 mm, a tensile speed of 50 mm / min, and a sampling interval of 20 μm until the test piece broke. Based on the obtained measurement results, a stress-strain curve was prepared with stress (unit: MPa) on the vertical axis and strain (unit: %) on the horizontal axis. The value of the strain when the test piece broke was taken as the elongation at break, and the value of the maximum stress when the test piece broke was taken as the breaking strength. Young's modulus was calculated by finding the slope of the stress-strain curve when the strain was 0-10%. The fracture energy was calculated by finding the area of ​​the portion surrounded by the stress-strain curve and the horizontal axis.

[0193] <Evaluation>

[0194] The following evaluations were performed on the laminated bodies obtained in Examples 1 to 12 and Comparative Examples 1 to 3 and the thin plate glass of Comparative Example 4. The results are shown in Table 1.

[0195] (Total transmittance and haze)

[0196] The total light transmittance and haze were measured using HazeMeter NDH2000 (manufactured by Nippon Denshoku Industries, Ltd.).

[0197] (Pen drop test)

[0198] The laminate was placed on a 10 mm thick SUS plate with the thin plate glass side of the laminate facing upward, and a ballpoint pen (BIC Japan, Orange EG0.7, 0.7 mm φ tip, 5.75 g weight) was dropped vertically from a predetermined height toward the glass surface of the laminate with the tip facing downward. The maximum height at which no cracks were generated in the thin plate glass was taken as the test result.

[0199] (Anti-scattering test)

[0200] The anti-scattering property of the laminated body in which cracks were generated in the thin plate glass in the above-mentioned pen drop test was evaluated based on the following evaluation criteria.

[0201] ◯: Cracks occurred in the glass, but the individual pieces of glass separated by the cracks were maintained by the resin layer, and there was no separation between the resin layer and the thin plate glass, and no scattering of the glass was observed.

[0202] ×: The thin plate glass cracked and the resin layer also cracked and separated into pieces, or the resin layer and the thin plate glass separated, so that the glass separated into pieces.

[0203] (Bending durability test)

[0204] A U-shaped bending tester (manufactured by YUASA SYSTEM Equipment Co., Ltd., DLDMLH-FS) was used to repeatedly bend the laminate in such a manner that the thin plate glass was arranged on the inside when the laminate was bent, under the conditions of a test speed of 2 seconds / time, a bending diameter of R3.0mm, and a bending number of 100,000 times. Then, in a state where the laminate was arranged on a movable plate in a horizontal state, the two movable plates were rotated 90 degrees, thereby bending the laminate into a U shape. Then, after the test, the appearance of the laminate was confirmed by visual inspection. The situation where there was no change in appearance before and after the test was evaluated as "○○", the situation where cracks and whitening occurred at the ends after the test but no cracks and whitening occurred outside the ends was evaluated as "○", and the situation where cracks and whitening occurred outside the ends after the test and the appearance changed was evaluated as "×".

[0205] [Table 1]

[0206]

[0207] (Examples 13 to 25)

[0208] The curable resin shown in (1), the initiator shown in (2), and the surface modifier shown in (3) were stirred and mixed according to the mixing ratio described in Table 2 below to obtain a resin composition. The obtained resin composition was diluted with propylene glycol monomethyl ether acetate as a solvent to adjust the viscosity, and applied to a thin plate glass with a thickness of 50 μm in a manner to obtain a thickness after drying described in Table 2 below. The obtained coating film was dried at a temperature of 100°C for 15 minutes and then irradiated with an amount of 1500 mJ / cm 2 The thin glass was cured by irradiating with ultraviolet light having a wavelength of 365 nm and heating at 80° C. for 30 minutes. As a result, a laminated body was obtained, which had a first resin layer formed of a cured resin on one side (viewing side) of the thin glass and a second resin layer formed of a cured resin on the other side (display element side).

[0209] (1) Curable resin

[0210] ·EPICLON EXA-830LVP (a mixture of bisphenol F type liquid epoxy resin and bisphenol A type liquid epoxy resin, manufactured by DIC Corporation)

[0211] ·jER YX7400N (polyether skeleton liquid epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd.)

[0212] ·jER 4005P (bisphenol F type solid epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd.)

[0213] ·jER YX8000 (hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent 192-220)

[0214] ·jER YX8034 (hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent 250-360)

[0215] ·jER YX8040 (hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent 900-1500)

[0216] CELLOXIDE 2021P (3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, manufactured by Daicel)

[0217] ETRENACOLL EHO (3-ethyl-3-hydroxymethyloxetane, manufactured by Ube Industries, Ltd.)

[0218] (2) Initiator

[0219] ·CPI-210S (triarylsulfonium salt-type photocationic polymerization initiator, manufactured by San-Apro)

[0220] ·DTS-200 (Aromatic sulfonium salt type photocationic polymerization initiator, manufactured by Midori Kagaku Co., Ltd.)

[0221] (3) Surface modifier

[0222] BYK-340 (BYK-Chemie)

[0223] ·JAR-33 (organic modified polysiloxane, manufactured by JUJO CHEMICAL)

[0224] <Physical property measurement>

[0225] The physical properties of the cured resins produced in Examples 13 to 25 were measured by the following methods. The results are shown in Table 2 below.

[0226] (Storage modulus and glass transition temperature)

[0227] A test piece of the cured resin with a thickness of 0.5 mm, a width of 5 mm, and a length of 50 mm was prepared, and a viscoelastic spectrometer (manufactured by IT Instruments & Controls, DVA-200) was used to measure the dynamic viscoelastic spectrum from -50°C to 150°C under the conditions of 10°C / min and 10 Hz in the tensile mode. The storage modulus at 25°C was obtained from the obtained dynamic viscoelastic spectrum. In addition, the temperature of the maximum value of the loss tangent was taken as the glass transition temperature Tg (°C).

[0228] (Young's modulus, elongation at break, breaking strength, breaking energy)

[0229] According to JIS K7113 "Tensile Test Method for Plastics", a test piece of a resin cured product with a thickness of 0.5 mm and molded into a dumbbell sample (SDK-400) was made, and a tensile test was carried out using a tensile testing machine. The tensile test was carried out under the conditions of a distance between chucks of 20 mm, a tensile speed of 50 mm / min, and a sampling interval of 20 μm until the test piece broke. Based on the obtained measurement results, a stress-strain curve was prepared with stress (unit: MPa) on the vertical axis and strain (unit: %) on the horizontal axis. The value of the strain when the test piece broke was taken as the elongation at break, and the value of the maximum stress when the test piece broke was taken as the breaking strength. Young's modulus was calculated by finding the slope of the stress-strain curve when the strain was 0-10%. The fracture energy was calculated by finding the area of ​​the portion surrounded by the stress-strain curve and the horizontal axis.

[0230] <Evaluation>

[0231] The following evaluations were performed on the thin plate glasses of the laminates obtained in Examples 13 to 25. The results are shown in Table 2 below.

[0232] (Total transmittance and haze)

[0233] The total light transmittance and haze were measured using HazeMeter NDH2000 (manufactured by Nippon Denshoku Industries, Ltd.).

[0234] (Pen drop test)

[0235] The laminate was placed on an artificial marble plate (manufactured by DuPont, "Corian") with a thickness of 10 mm, with the first resin layer side of the laminate facing upward, and a ballpoint pen (manufactured by BIC Japan, Orange EG0.7, 0.7 mmφ tip, 5.75 g weight) was dropped vertically from a predetermined height toward the first resin layer side of the laminate, with the tip of the pen facing downward. The maximum height at which no cracks were generated in the thin plate glass was taken as the test result.

[0236] (Anti-scattering test)

[0237] The anti-scattering property of the laminated body in which cracks were generated in the thin plate glass in the above-mentioned pen drop test was evaluated based on the following evaluation criteria.

[0238] ◯: Cracks occurred in the glass, but the individual pieces of glass separated by the cracks were maintained by the resin layer, and there was no separation between the resin layer and the thin plate glass, and no scattering of the glass was observed.

[0239] ×: The thin plate glass cracked and the resin layer also cracked and separated into pieces, or the resin layer and the thin plate glass separated, so that the glass separated into pieces.

[0240] (Bending durability test)

[0241] A U-shaped bending tester (manufactured by YUASA SYSTEM Equipment Co., Ltd., DLDMLH-FS) was used to arrange the laminate so that the first resin layer became the inner side when the laminate was bent, and the laminate was bent repeatedly under the conditions of a test speed of 1 second / time, a bending diameter of R2.0 mm, and a bending number of 100,000 times. Then, after the test, the bent portion of the laminate was visually confirmed. The case where there was no change in appearance before and after the test was evaluated as "○○", the case where cracks and whitening occurred at the end after the test but no cracks and whitening occurred outside the end was evaluated as "○", and the case where cracks and whitening occurred outside the end after the test and the appearance changed was evaluated as "×".

[0242] [Table 2]

[0243]

[0244] Industrial Applicability

[0245] According to the present invention, a laminate having excellent impact resistance can be provided. In addition, according to the present invention, an electronic device and a cover glass using the laminate, and a resin composition for forming a resin layer of the laminate can be provided.

[0246] Description of Reference Numerals

[0247] 10: Laminated body

[0248] 11: 1st resin layer

[0249] 12: Thin plate glass

[0250] 13: Second resin layer

[0251] 14: Transparent adhesive for optics

[0252] 15: Polarizing plate

Claims

1. A laminate, It is characterized in that A thin plate glass having a thickness of 200 μm or less and a resin layer having a thickness of 5 μm or more and arranged on at least one side of the thin plate glass. The fracture energy of the resin layer is 1 mJ / mm 3 The storage modulus of the resin layer at 25° C. is 2500 MPa or less.

2. The laminate according to claim 1, in, The resin layer has a Young's modulus of 50 MPa or more and 1500 MPa or less.

3. The laminate according to claim 1 or 2, in, The storage modulus of the resin layer at 25° C. is 2000 MPa or less.

4. The laminate according to claim 1 or 2, in, The resin layer has a glass transition temperature of 100° C. or less.

5. The laminate according to claim 1 or 2, in, The resin layer contains a polymer of a cation-curable resin.

6. The laminate according to claim 5, in, The cationically curable resin includes an epoxy group-containing compound and an oxetane group-containing compound.

7. The laminate according to claim 6, in, The epoxy group-containing compound includes a hydrogenated bisphenol-type epoxy resin.

8. The laminate according to claim 7, in, The hydrogenated bisphenol-based epoxy resin comprises a hydrogenated bisphenol A skeleton.

9. The laminate according to claim 7, in, The epoxy equivalent of the hydrogenated bisphenol epoxy resin is 100 or more and 2000 or less.

10. The laminate according to claim 6, in, The epoxy group-containing compound includes an epoxy resin having a polyether skeleton.

11. The laminate according to claim 10, in, The epoxy resin having a polyether skeleton is in liquid state at 23°C.

12. The laminate according to claim 6, in, The oxetane-containing compound is monofunctional.

13. The laminate according to claim 5, in, The cationic curable resin includes a hydrogenated bisphenol-type epoxy resin, an epoxy resin having a polyether skeleton, and an oxetane group-containing compound.

14. The laminate according to claim 13, in, In the resin layer, the content of the hydrogenated bisphenol-type epoxy resin is greater than 20 wt % and less than 60 wt %, the content of the epoxy resin having a polyether skeleton is greater than 10 wt % and less than 20 wt %, and the content of the oxetane-containing compound is greater than 20 wt % and less than 60 wt %.

15. The laminate according to claim 1, comprising: a first resin layer disposed on one side of the thin plate glass and having a thickness of 5 μm or more; and The second resin layer is disposed on the side of the thin plate glass opposite to the first resin layer side and has a thickness of 5 μm or more. The breaking energy of the first resin layer and the second resin layer is 1 mJ / mm 3 The storage modulus at 25°C is 2500 MPa or less.

16. The laminate according to claim 6, in, The Young's modulus of the first resin layer and the second resin layer are both 50 MPa or more and 1500 MPa or less.

17. The laminate according to claim 15 or 16, in, At least one of the first resin layer and the second resin layer has a thickness of 25 μm or less.

18. The laminate according to claim 15 or 16, in, At least one of the first resin layer and the second resin layer has a glass transition temperature of 100° C. or less.

19. The laminate according to claim 15 or 16, in, At least one of the first resin layer and the second resin layer contains a polymer of a cation-curable resin.

20. A laminate, It is characterized in that A thin plate glass having a thickness of 200 μm or less and a resin layer having a thickness of 5 μm or more and arranged on at least one side of the thin plate glass. The resin layer has a Young's modulus of 50 MPa or more and 1500 MPa or less.

21. The laminate according to claim 20, in, The fracture energy of the resin layer is 1 mJ / mm 3 above.

22. The laminate according to claim 20 or 21, in, The storage modulus of the resin layer at 25° C. is 2500 MPa or less.

23. The laminate according to claim 20 or 21, in, The resin layer has a glass transition temperature of 100° C. or less.

24. The laminate according to claim 20 or 21, in, The resin layer contains a polymer of a cation-curable resin.

25. The laminate according to claim 24, in, The cationically curable resin includes an epoxy group-containing compound and an oxetane group-containing compound.

26. The laminate according to claim 25, in, The epoxy group-containing compound includes a hydrogenated bisphenol-type epoxy resin.

27. The laminate according to claim 26, in, The hydrogenated bisphenol-based epoxy resin comprises a hydrogenated bisphenol A skeleton.

28. The laminate according to claim 26, in, The epoxy equivalent of the hydrogenated bisphenol epoxy resin is 100 or more and 2000 or less.

29. The laminate according to claim 25, in, The epoxy group-containing compound includes an epoxy resin having a polyether skeleton.

30. The laminate according to claim 29, in, The epoxy resin having a polyether skeleton is in liquid state at 23°C.

31. The laminate according to claim 25, in, The oxetane-containing compound is monofunctional.

32. The laminate according to claim 24, in, The cationic curable resin includes a hydrogenated bisphenol-type epoxy resin, an epoxy resin having a polyether skeleton, and an oxetane group-containing compound.

33. The laminate according to claim 32, in, In the resin layer, the content of the hydrogenated bisphenol-type epoxy resin is greater than 20 wt % and less than 60 wt %, the content of the epoxy resin having a polyether skeleton is greater than 10 wt % and less than 20 wt %, and the content of the oxetane-containing compound is greater than 20 wt % and less than 60 wt %.

34. The laminate according to claim 20, comprising: a first resin layer disposed on one side of the thin plate glass and having a thickness of 5 μm or more; and The second resin layer is disposed on the side of the thin plate glass opposite to the first resin layer side and has a thickness of 5 μm or more. The Young's modulus of the first resin layer and the second resin layer are both 50 MPa or more and 1500 MPa or less.

35. The laminate according to claim 34, in, At least one of the first resin layer and the second resin layer has a storage modulus at 25° C. of 3000 MPa or less.

36. The laminate according to claim 34 or 35, in, At least one of the first resin layer and the second resin layer has a thickness of 25 μm or less.

37. The laminate according to claim 34 or 35, in, At least one of the first resin layer and the second resin layer has a glass transition temperature of 100° C. or less.

38. The laminate according to claim 34 or 35, in, At least one of the first resin layer and the second resin layer contains a polymer of a cation-curable resin.

39. The laminate according to claim 38, in, The cationically curable resin includes an epoxy group-containing compound and an oxetane group-containing compound.

40. The laminate according to claim 39, in, The epoxy group-containing compound includes a hydrogenated bisphenol-type epoxy resin.

41. The laminate according to claim 40, in, The hydrogenated bisphenol-based epoxy resin comprises a hydrogenated bisphenol A skeleton.

42. The laminate according to claim 40, in, The epoxy equivalent of the hydrogenated bisphenol epoxy resin is 100 or more and 2000 or less.

43. The laminate according to claim 39, in, The epoxy group-containing compound includes an epoxy resin having a polyether skeleton.

44. The laminate according to claim 43, in, The epoxy resin having a polyether skeleton is in liquid state at 23°C.

45. The laminate according to claim 39, in, The oxetane-containing compound is monofunctional.

46. ​​The laminate according to claim 38, in, The cationic curable resin includes a hydrogenated bisphenol-type epoxy resin, an epoxy resin having a polyether skeleton, and an oxetane group-containing compound.

47. The laminate according to claim 46, in, In the resin layer containing the polymer of the cationic curable resin, the content of the hydrogenated bisphenol-type epoxy resin is greater than 20 wt % and less than 60 wt %, the content of the epoxy resin having a polyether skeleton is greater than 10 wt % and less than 20 wt %, and the content of the oxetane-containing compound is greater than 20 wt % and less than 60 wt %.

48. An electronic device comprising the laminate according to any one of claims 1 to 47. A cover glass comprising the laminate according to any one of claims 1 to 47. 50 . A resin composition for forming a resin layer of the laminate according to claim 1 .

51. A resin composition comprising a hydrogenated bisphenol-type epoxy resin, an epoxy resin having a polyether skeleton, and an oxetane-containing compound. 52 . The resin composition according to claim 50 or 51 , which is used for coating on a thin plate glass having a thickness of 200 μm or less.

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