WO2023277060A1

WO2023277060A1 - Laminate, electronic device, resin composition and cover glass

Info

Publication number: WO2023277060A1
Application number: PCT/JP2022/025950
Authority: WO
Inventors: 穣末▲崎▼
Original assignee: 積水化学工業株式会社
Priority date: 2021-06-30
Filing date: 2022-06-29
Publication date: 2023-01-05
Also published as: KR20240026880A; TW202319234A; JPWO2023277060A1

Abstract

The present invention provides a laminate which exhibits excellent shock resistance. The purpose of the present invention is to provide: an electronic device and cover glass which are obtained using said laminate; and a resin composition used in order to form the resin layer of said laminate. The present invention is a laminate having a thin glass sheet which has a thickness no greater than 200μm and a resin layer which has a thickness of 5μm or greater and is positioned on one or more sides of the thin glass sheet, wherein the breaking energy of the resin layer is at least 1mJ/mm3 and the storage modulus at 25°C is no greater than 2,500MPa, or the present invention is a laminate having a thin glass sheet which has a thickness no greater than 200μm and a resin layer which has a thickness of 5μm or greater and is positioned on one or more sides of the thin glass sheet, wherein the Young's modulus of the resin layer is 50-1,500MPa, inclusive.

Description

Laminates, electronic devices, resin compositions and cover glasses

TECHNICAL FIELD The present invention relates to a laminate having excellent impact resistance. The present invention also relates to an electronic device and a cover glass using the laminate, and a resin composition used for forming a resin layer of the laminate.

2. Description of the Related Art In recent years, the development of foldable display screens of electronic devices such as smartphones, electronic books, and tablet PCs has been progressing. The use of flexible thin plate glass on the outermost surface side of such a foldable display screen is under study.

Since thin glass is easily broken by impact, it is being studied to arrange a protective resin layer on one side of the thin glass. For example, Patent Document 1 discloses a protective substrate for a display device comprising glass and a resin layer on one side of the glass, wherein 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 to 1.5 g/cm ³ and the bending elastic modulus of the resin layer at 25° C. is 1000 MPa to 8000 MPa. Further, Patent Document 2 discloses a thin glass having a thickness of 120 μm or less and a shock absorbing layer having a thickness of 5 μm or more disposed on one side of the thin glass, and the shock absorbing layer has a thickness of 5 μm or more at 25° C. Optical laminates with tan δ maxima in the range of 10 ¹ to 10 ¹⁵ Hz are described. However, when a conventional resin composition is used to form a protective resin layer, the impact resistance is insufficient.

JP 2013-37207 A WO2018/190208

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 used for forming the resin layer of the laminate.

The present disclosure 1 has a thin plate glass with a thickness of 200 μm or less and a resin layer with a thickness of 5 μm or more disposed on at least one side of the thin plate glass, and the breaking energy of the resin layer is 1 mJ / mm. ³ or more and a storage modulus at 25° C. of 2500 MPa or less (first laminate).
The present disclosure 2 is the laminate according to the present disclosure 1, wherein the resin layer has a Young's modulus of 50 MPa or more and 1500 MPa or less.
Present Disclosure 3 is the laminate according to Present Disclosure 1 or 2, wherein the resin layer has a storage elastic modulus at 25° C. of 2000 MPa or less.
Present Disclosure 4 is the laminate according to Present Disclosure 1, 2, or 3, wherein the resin layer has a glass transition temperature of 100° C. or less.
Present Disclosure 5 is the laminate of Present Disclosure 1, 2, 3 or 4, wherein the resin layer contains a cationic curable resin polymer.

The present disclosure 6 is a first resin layer having a thickness of 5 μm or more, which is arranged on one side of the thin glass, and a thick and a second resin layer having a thickness of 5 μm or more, wherein both the first resin layer and the second resin layer have a breaking energy of 1 mJ/mm ³ or more and storage elasticity at 25 ° C. The laminate of the present disclosure 1, having a modulus of 2500 MPa or less.
The present disclosure 7 is the laminate according to the present disclosure 6, wherein both the first resin layer and the second resin layer have a Young's modulus of 50 MPa or more and 1500 MPa or less.

The present disclosure 8 has a thin plate glass with a thickness of 200 μm or less, and a resin layer with a thickness of 5 μm or more disposed on at least one side of the thin plate glass, wherein the resin layer has a Young's modulus of 50 MPa or more, A laminated body (second laminated body) having a tensile strength of 1500 MPa or less.
Present Disclosure 9 is the laminate according to Present Disclosure 8, wherein the breaking energy of the resin layer is 1 mJ/mm ³ or more.
Present Disclosure 10 is the laminate according to Present Disclosure 8 or 9, wherein the resin layer has a storage modulus at 25° C. of 2500 MPa or less.
Present Disclosure 11 is the laminate according to Present Disclosure 8, 9, or 10, wherein the resin layer has a glass transition temperature of 100° C. or lower.
Disclosure 12 is the laminate of

Disclosure

8, 9, 10 or 11, wherein the resin layer comprises a cationic curable resin polymer.
The present disclosure 13 is a first resin layer having a thickness of 5 μm or more, which is arranged on one side of the thin glass plate, and a thick and a second resin layer having a thickness of 5 μm or more, and the Young's modulus of both the first resin layer and the second resin layer is 50 MPa or more and 1500 MPa or less. be.
Present Disclosure 14 is the laminate according to Present Disclosure 13, wherein at least one of the first resin layer and the second resin layer has a storage elastic modulus at 25° C. of 3000 MPa or less.
15 of the present disclosure is the laminate according to 6, 7, 13, or 14 of the present disclosure, wherein at least one of the first resin layer and the second resin layer has a thickness of 25 μm or less.
16 of the present disclosure is the laminate according to 6, 7, 13, 14, or 15 of the present disclosure, wherein at least one of the first resin layer and the second resin layer has a glass transition temperature of 100° C. or less.
The present disclosure 17 is the laminate according to the

present disclosure

6, 7, 13, 14, 15 or 16, wherein at least one of the first resin layer and the second resin layer contains a cationic curable resin polymer be.

18 of the present disclosure is an electronic device including the laminate according to any one of 1 to 17 of the present disclosure.
A 19th aspect of the present disclosure is a resin composition used for forming a resin layer of the laminate of any one of the 1st to 17th aspects of the present disclosure.
The present disclosure 20 is a cover glass comprising the laminate of any one of the present disclosures 1-17.
The present invention will be described in detail below.

As a result of examining the resin layer arranged on at least one side of the thin plate glass, the present inventor focused on the correlation between the breaking energy and storage elastic modulus of the resin layer and impact resistance, and set the breaking energy to 1 mJ / mm ³ or more. and the storage elastic modulus at 25° C. of 2500 MPa or less, sufficient impact resistance can be obtained.
In addition, the present inventors examined the resin layer disposed on at least one side of the thin glass sheet, and focused on the correlation between the Young's modulus of the resin layer and the impact resistance, and set the Young's modulus to 50 MPa or more and 1500 MPa or less. It has been found that sufficient impact resistance can be obtained by doing so.
Furthermore, the present inventors have studied how to improve impact resistance by laminating a resin layer on the surface of a thin glass plate placed on a display surface of an electronic device or the like. Glass scattering can be effectively prevented by providing the first and second resin layers. was found to be able to increase
As described above, the inventor has completed the present invention.

The laminate of the present invention (hereinafter also referred to as the "laminate of the present invention" for matters common to the first laminate and the second laminate) comprises a thin glass having a thickness of 200 μm or less and the above and a resin layer having a thickness of 5 μm or more disposed on at least one side of the thin plate glass. At least one resin layer may be provided in the laminate of the present invention. For example, one or more resin layers may be disposed on one side of the thin glass plate, or may One or more layers of the resin layer may be arranged. In addition, the laminate of the present invention may have layers other than the thin glass sheet and the resin layer. For example, the resin layer may be laminated with the thin glass sheet via an adhesive layer. However, it is preferable to directly contact the thin sheet glass without an adhesive layer. From the viewpoint of making the most of the advantage of using flexible thin plate glass, a configuration in which only one layer of the resin layer is arranged on one side of the thin plate glass, and one resin layer is arranged on each side of the thin plate glass. configuration is preferred. When the resin layer is provided without an adhesive layer, a method of forming the resin layer by applying a resin composition, which is the material of the resin layer, on the surface of the thin glass plate and curing the resin composition is preferably used.

Moreover, it is preferable that the laminated body of this invention has the said thin plate glass or said resin layer arrange|positioned on the outermost surface. That is, the laminate of the present invention may have a structure in which the thin sheet glass is arranged on the outermost surface and the resin layer is arranged thereunder, or the resin layer is arranged on the outermost surface and the resin layer is arranged thereunder. A configuration in which the thin plate glass is arranged may be used. Among these, from the viewpoint of achieving both the scratch resistance of glass and the improvement of impact resistance by the resin layer, a configuration in which the thin plate glass is arranged on the outermost surface and the resin layer is arranged below it is particularly preferable.

The resin layer preferably covers an area of 80% or more of the thin plate glass in plan view, and more preferably covers the entire surface of the thin plate glass.

The configurations of the first laminate and the second laminate are appropriately selected depending on the application. , having the configuration shown in FIG. FIG. 1 is a schematic cross-sectional view showing an example of the structure of the laminate of the present invention. In FIG. 1, the laminated body 10 includes a first resin layer 11 on one side (visible side) of the thin glass plate 12, and the side opposite to the first resin layer 11 side of the thin glass plate 12 (display device side). , and may be integrated with the polarizing plate 15 with an optical transparent adhesive (OCA) 14 .

The thin plate glass is not particularly limited as long as it is plate-shaped and has a thickness of 200 μm or less. Examples of the composition of the thin plate glass include soda-lime glass, boric acid glass, aluminosilicate glass, and quartz glass. Moreover, according to the classification by the alkali component, non-alkali glass and low-alkali glass can be mentioned. From the standpoint of impact resistance, the thin sheet glass is preferably chemically strengthened glass that has undergone chemical strengthening treatment. The chemically strengthened glass preferably has a compressive stress layer formed on its surface by chemical strengthening treatment (ion exchange treatment).

The thickness of the thin plate glass is 200 μm or less. When the thickness of the thin plate glass is 200 μm or less, flexibility required for foldable electronic devices can be obtained. In addition, the thinner the thickness of the sheet glass, the more remarkable the improvement in impact resistance due to the resin layer. The thickness of the thin plate glass is preferably 150 μm or less, more preferably 100 μm or less. Further, the thickness of the thin plate glass is preferably 5 µm or more, more preferably 10 µm or more, still more preferably 20 µm or more, and particularly preferably 30 µm or more. When the thin plate glass has a certain thickness or more, both flexibility and impact resistance can be achieved.

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.

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

The method for producing the glass used for the above-mentioned thin glass is not particularly limited. It is produced by melting at a temperature of 1600° C. to 1600° C., molding it into a thin plate, and then cooling it. Examples of the method for forming a thin sheet of glass include a slot down draw method, a fusion method, a float method, and the like. The glass formed into a plate shape by these methods may be chemically polished with a solvent such as hydrofluoric acid, if necessary, in order to thin the plate or improve smoothness.

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

As the thin plate glass, a commercially available one may be used as it is, or a commercially available glass may be used after being subjected to additional treatment such as polishing and etching so as to have a desired thickness.

<First laminate>
The resin layer has a breaking energy of 1 mJ/mm ³ or more. When the breaking energy of the resin layer is 1 mJ/mm ³ or more, sufficient impact resistance can be imparted to the thin glass that is thinned to realize a foldable electronic device. The breaking energy is preferably 1.5 mJ/mm ³ or more, more preferably 2 mJ/mm ³ or more. Although the upper limit of the breaking energy is not particularly limited, it is, for example, 50 mJ/mm ³ or less from the viewpoint of ensuring other properties of the laminate.

The above breaking energy was measured according to JIS K7113 "Plastic tensile test method" using a test piece prepared according to the following procedure. A release-treated polyethylene terephthalate resin film was placed on a glass plate with a thickness of 0.7 mm, with the release surface facing upward, and a silicon with a thickness of 0.5 mm was punched into a dumbbell shape (SDK-400). Install the sheet mold. The resin composition used for forming the resin layer was poured into a dumbbell mold, and the resin liquid was covered with the release surface of the release-treated polyethylene terephthalate resin film so as not to entrain air bubbles. Stack the glass plates. Next, an ultraviolet LED with a wavelength of 365 nm and an illuminance of 100 mW/cm ² is used as a light source, and exposed through the glass plate for 15 seconds to irradiate with ultraviolet rays of 1500 mJ/cm ² . Furthermore, while being sandwiched between the glass plates, it is turned over, and the same ultraviolet rays are applied again from the back side. Thereafter, the resin is cured by heating in an oven at 80° C. for 30 minutes, and the cured resin is removed from the silicon sheet mold to obtain a test piece. This test piece is subjected to a tensile test using a tensile tester. The tensile test is performed at a distance between chucks of 25 mm, a tensile speed of 50 mm/min, and a sampling interval of 20 μm until the test piece breaks. From the obtained measurement results, stress (unit: MPa) is taken on the vertical axis and strain (unit: %) is taken on the horizontal axis - Create a strain curve, this stress - surrounded by the strain curve and the horizontal axis The breaking energy can be calculated by finding the area of the portion where the fracture occurs.

When the breaking energy of the resin layer is directly measured from the laminate, the resin layer is punched into a dumbbell shape (SDK-400), and this is used as the test piece. Alternatively, after dissolving the resin layer in a solvent to obtain a resin liquid, the resin liquid is poured into the dumbbell mold, and the solvent is completely dried to obtain a test piece.

The resin layer preferably has a Young's modulus of 1500 MPa or less. When the Young's modulus of the resin layer is 1500 MPa or less, the resin layer can have appropriate flexibility. In addition, when the glass is broken, the resin film is hard to be broken at the same time, and a scattering prevention effect can be obtained. The Young's modulus is more preferably 1300 MPa or less, still more preferably 1200 MPa or less. Although the lower limit of the Young's modulus is not particularly limited, it is preferably 50 MPa or more from the viewpoint of ensuring the impact resistance of the laminate. The Young's modulus can be calculated by creating a stress-strain curve in the same manner as in the measurement of the breaking energy, and determining the slope of the stress-strain curve at a strain of 0 to 10%.

The resin layer has a storage modulus of 2500 MPa or less at 25°C. When the storage elastic modulus of the resin layer is 2500 MPa or less, sufficient impact resistance can be imparted to the thin glass. Moreover, since the flexibility of the resin layer can be ensured, the laminate can have the flexibility required for realizing a foldable electronic device. The storage modulus is preferably 2000 MPa or less, more preferably 1800 MPa or less. Although the lower limit of the storage elastic modulus is not particularly limited, it is, for example, 100 MPa or more from the viewpoint of ensuring the impact resistance of the laminate.

In addition, in the measurement of the storage modulus, two test pieces of cured resin prepared in the same manner as in the measurement of the breaking energy are superimposed so as to have a thickness of 1 mm to prepare a measurement sample. For the prepared measurement sample, using a viscoelastic spectrometer (for example, DVA-200 manufactured by IT Instrument Control Co., Ltd.), under the conditions of 5 ° C./min and 1 Hz in the slow heating shear deformation mode, -50 ° C. to 200 ° C. It can be obtained as a storage modulus at 25° C. when the dynamic viscoelasticity spectrum of is measured.

<Second laminate>
The resin layer has a Young's modulus of 50 MPa or more and 1500 MPa or less. The Young's modulus of the resin layer is 50 MPa or more and 1500 MPa or less, so that moderate flexibility for realizing a foldable electronic device is obtained, and the thickness is reduced to realize a foldable electronic device. Sufficient impact resistance can be imparted to the thin glass. The Young's modulus is preferably 1300 MPa or less, more preferably 1200 MPa or less, and preferably 80 MPa or more.

The Young's modulus was measured according to JIS K7113 "Plastic tensile test method" using a test piece prepared according to the following procedure. A release-treated polyethylene terephthalate resin film was placed on a glass plate with a thickness of 0.7 mm, with the release surface facing upward, and a silicon with a thickness of 0.5 mm was punched into a dumbbell shape (SDK-400). Install the sheet mold. The resin composition used for forming the resin layer was poured into a dumbbell mold, and the resin liquid was covered with the release surface of the release-treated polyethylene terephthalate resin film so as not to entrain air bubbles. Stack the glass plates. Next, an ultraviolet LED with a wavelength of 365 nm and an illuminance of 100 mW/cm ² is used as a light source, and exposed through the glass plate for 15 seconds to irradiate with ultraviolet rays of 1500 mJ/cm ² . Furthermore, while being sandwiched between the glass plates, it is turned over, and the same ultraviolet rays are applied again from the back side. Thereafter, the resin is cured by heating in an oven at 80° C. for 30 minutes, and the cured resin is removed from the silicon sheet mold to obtain a test piece. This test piece is subjected to a tensile test using a tensile tester. The tensile test is performed at a distance between chucks of 25 mm, a tensile speed of 50 mm/min, and a sampling interval of 20 μm until the test piece breaks. From the measurement results obtained, a stress (unit: MPa) is taken on the vertical axis and a strain (unit: %) is taken on the horizontal axis - a strain curve is created, and the strain of this stress - strain curve is 0 to 1 It can be calculated by finding the slope in %.

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), which is used as the test piece. Alternatively, after dissolving the resin layer in a solvent to obtain a resin liquid, the resin liquid is poured into the dumbbell mold, and the solvent is completely dried to obtain a test piece.

The resin layer preferably has a breaking energy of 1 mJ/mm ³ or more. When the breaking energy of the resin layer is 1 mJ/mm ³ or more, the impact resistance of the laminate can be further improved. The breaking energy is preferably 1.5 mJ/mm ³ or more, more preferably 2 mJ/mm ³ or more. Although the upper limit of the breaking energy is not particularly limited, it is, for example, 50 mJ/mm ³ or less from the viewpoint of ensuring other properties of the laminate. The breaking energy can be calculated by creating a stress-strain curve in the same manner as in the measurement of the Young's modulus and finding the area of the portion surrounded by this stress-strain curve and the horizontal axis. can.

The resin layer preferably has a storage modulus of 2500 MPa or less at 25°C. When the storage elastic modulus of the resin layer is 2500 MPa or less, the flexibility of the resin layer can be ensured, which is preferable for a laminate having the flexibility required for realizing a foldable electronic device. . The storage elastic modulus is more preferably 2000 MPa or less, still more preferably 1800 MPa or less. Although the lower limit of the storage elastic modulus is not particularly limited, it is, for example, 100 MPa or more from the viewpoint of ensuring the impact resistance of the laminate.

For the measurement of the storage elastic modulus, two test pieces of the cured resin prepared in the same manner as in the measurement of the breaking energy are laminated to a thickness of 1 mm to prepare a measurement sample. For the prepared measurement sample, using a viscoelastic spectrometer (for example, DVA-200 manufactured by IT Instrument Control Co., Ltd.), under the conditions of 5 ° C./min and 1 Hz in the slow heating shear deformation mode, -50 ° C. to 200 ° C. It can be obtained as a storage modulus at 20 ° C. when measuring the dynamic viscoelastic spectrum of.

<First and second laminates>
The resin layer preferably has an elongation at break of 5% or more. When the elongation at break of the resin layer is 5% or more, cracks and whitening are less likely to occur in a bending endurance test. More preferably, the elongation at break of the resin layer is 7% or more. There is no particular upper limit for the elongation at break, but from the viewpoint of ensuring the impact resistance of the laminate, it is preferably 1000% or less. As the elongation at break, a tensile test is performed in the same manner as in the measurement of the breaking energy, and the value of the strain when the test piece breaks can be used.

The resin layer preferably has a breaking strength of 5 MPa or more and 50 MPa or less. When the breaking strength of the resin layer is within the range of 5 MPa or more and 50 MPa or less, it becomes easy to impart sufficient impact resistance to the thin glass. More preferably, the breaking strength of the resin layer is 10 MPa or more and 40 MPa or less. For the breaking strength, a tensile test is performed in the same manner as in the measurement of the breaking energy, and the value of the stress when the test piece breaks can be used.

The resin layer preferably has a glass transition temperature of 100° C. or lower. When the glass transition temperature of the resin layer is 100° C. or less, the flexibility of the resin layer can be ensured. preferable. The glass transition temperature is more preferably 80° C. or lower. The lower limit of the glass transition temperature is not particularly limited, but is, for example, 0° C. or higher from the viewpoint of ensuring other properties of the laminate. As for the glass transition temperature, a dynamic viscoelastic spectrum is prepared in the same manner as in the measurement of the storage elastic modulus, and the temperature at which the loss tangent has a maximum value can be used.

The resin layer preferably has a total light transmittance of 80% or more. When the total light transmittance of the resin layer is 80% or more, the transparency of the resin layer can be ensured. It is preferable to form a laminate. The total light transmittance is more preferably 90% or more. The total light transmittance can be measured using, for example, HazeMeter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The above total light transmittance is measured by a method conforming to JIS K 7361-1.

The thickness of the resin layer is 5 μm or more. When the thickness of the resin layer is 5 μm or more, the flexible resin layer can exert a shock absorbing function, and the thin glass thinned to realize a foldable electronic device has sufficient shock resistance. You can give it character. 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, but from the viewpoint of ensuring the bendability of the laminate, it is preferably thinner than the thin plate glass. It is more preferably 30 μm or less, particularly preferably 20 μm or less.

Each material that can be used for the resin layer according to the present invention will be described below.
The resin composition used to form the resin layer is not particularly limited as long as it can adjust the physical properties of the resin layer obtained after curing to an appropriate range. It is preferably used. That is, the resin layer preferably contains a cationic curable resin polymer.

The cationic curable resin is not particularly limited as long as it has at least one cationic polymerizable functional group in the molecule and is highly cationic polymerizable.
Examples of the cationic polymerizable functional group include epoxy group, oxetanyl group, vinyl ether group, episulfide group, and ethyleneimine group. Among them, the cationic curable resin preferably contains an epoxy resin. Since the epoxy resin has excellent adhesion to the thin plate glass, it is possible to suppress peeling of the resin layer when the laminate of the present invention is repeatedly bent.

The epoxy resin 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; resins, aromatic epoxy resins such as trisphenolmethane triglycidyl ether, naphthalene-type epoxy resins, fluorene-type epoxy resins, dicyclopentadiene-type epoxy resins, polyether-modified epoxy resins, NBR-modified epoxy resins, CTBN-modified epoxy resins, and Hydrogenated products thereof and the like are included. These epoxy resins may be used alone or in combination of two or more.

The above-mentioned epoxy resin may be an epoxy resin that is liquid at normal temperature, or an epoxy resin that is solid at normal temperature, and these may be used in appropriate combination.
Among the epoxy resins that are liquid at room temperature, commercially available products include, for example, EPICLON 840, 840-S, 850, 850-S, EXA-850CRP (manufactured by DIC Corporation) and other bisphenol A type epoxy resins, EPICLON 830, Bisphenol F type epoxy resins such as 830-S, EXA-830CRP, EXA-830LVP (manufactured by DIC), jER 806H (manufactured by Mitsubishi Chemical), EPICLON HP-4032, HP-4032D (manufactured by DIC) Naphthalene type epoxy resin such as EPICLON EXA-7015 (manufactured by DIC), hydrogenated bisphenol A type epoxy resin such as EX-252 (manufactured by Nagase ChemteX), resorcinol such as EX-201 (manufactured by Nagase ChemteX) type epoxy resin, 3-ethyl-3-hydroxymethyloxetane (ETRENACOLL EHO, manufactured by Ube Industries, Ltd.), and the like.

Among the epoxy resins that are solid at room temperature, commercially available products include bisphenol A type epoxy resins such as EPICLON 860, 10550, and 1055 (manufactured by DIC Corporation), and bisphenol F type epoxy resins such as JER 4005P (manufactured by Mitsubishi Chemical Corporation). Epoxy resins, bisphenol S-type epoxy resins such as EPICLON EXA-1514 (manufactured by DIC), naphthalene-type epoxy resins such as EPICLON HP-4700, HP-4710, and HP-4770 (manufactured by DIC), EPICLON HP-7200 dicyclopentadiene type epoxy resins such as series (manufactured by DIC), cresol novolac type epoxy resins such as EPICLON HP-5000 and EXA-9900 (manufactured by DIC).

The resin composition preferably contains a polymerization initiator. The polymerization initiator may be a photopolymerization initiator or a thermal polymerization initiator. Examples of photopolymerization initiators include diphenyliodonium, 4-methoxydiphenyliodonium, bis(4-methylphenyl)iodonium, bis(4-tert-butylphenyl)iodonium, bis(dodecylphenyl)iodonium, diphenyl-4-thio phenoxyphenylsulfonium, bis[4-(diphenylsulfonio)-phenyl]sulfide, bis[4-(di(4-(2-hydroxyethyl)phenyl)sulfonio)-phenyl]sulfide, η5-2,4-( cations such as cyclopentagenyl)[1,2,3,4,5,6-η-(methylethyl)benzene]-iron(1+), tetrafluoroborate, hexafluorophosphate, triphenylhexafluorophosphate, Compounds that are combined with anions such as hexafluoroarsenate can be mentioned. Thermal polymerization initiators include, for example, imidazoles, quaternary ammonium salts, phosphorus compounds, amines, phosphines, phosphonium salts, bicyclic amidines and their salts, acid anhydrides, phenol, cresol, xylenol, Novolac type phenol resins obtained by condensation reaction of resorcinol and the like with formaldehyde, polymercapto resins such as liquid polymercaptan and polysulfide, and amides can be mentioned. These polymerization initiators may be used alone or in combination of two or more.

The content of the polymerization initiator has a preferable lower limit of 0.1 parts by weight and a preferable upper limit of 10 parts by weight with respect to 100 parts by weight of the cationic curable resin. If the content of the polymerization initiator is less than 0.1 part by weight, the cationic polymerization may not proceed sufficiently or the curing reaction may become too slow. If the content of the polymerization initiator exceeds 10 parts by weight, the curing reaction of the resin composition may become too fast, resulting in reduced workability and uneven composition of the resulting resin layer. . A more preferable lower limit to the content of the polymerization initiator is 0.5 parts by weight, and a more preferable upper limit is 5 parts by weight.

The resin composition further contains a solvent, a viscosity modifier, a surface modifier (surfactant, leveling agent), a plasticizer, a silane coupling agent, a tackifier, a sensitizer, as long as the object of the present invention is not impaired. It may contain various known additives such as curing agents, thermosetting agents, cross-linking agents, curing retarders, antioxidants, storage stabilizers, dispersants and fillers.

The method for preparing the resin composition is not particularly limited, and examples thereof include a method of mixing a curable resin, a polymerization initiator, and additives to be added as necessary using a mixer. be done. Examples of the mixer include a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, and three rolls.

The method for forming the resin layer is not particularly limited. For example, the resin layer can be formed by applying a resin composition on the surface of the thin plate glass and then curing the resin composition by light irradiation, heating, or the like. The method of applying the resin composition is not particularly limited, and for example, a screen printing method, a die coat printing method, an offset printing method, a gravure printing method, an inkjet printing method, or the like may be used.

Further, as a preferred form of the first laminated body and the second laminated body, a thin plate glass having a thickness of 200 μm or less and a first glass plate having a thickness of 5 μm or more arranged on one side of the thin plate glass and a second resin layer having a thickness of 5 μm or more, which is arranged on the opposite side of the thin plate glass from the first resin layer side. At least one layer of the first resin layer and the second resin layer may be provided in the first laminate and the second laminate. In the preferred embodiment, the first laminate and the second laminate may have layers other than the thin glass, the first resin layer, and the second resin layer. Well, for example, the first resin layer and the second resin layer may be laminated on the thin plate glass via an adhesive layer, but may be in direct contact with the thin plate glass without an adhesive layer. preferable. When the first resin layer and the second resin layer are provided without an adhesive layer interposed therebetween, a resin composition as a material for the first resin layer and the second resin layer is placed on the surface of the thin plate glass. A method of forming a resin layer by applying and curing a substance is preferably used.

The first resin layer and the second resin layer preferably cover an area of 80% or more of the thin glass plate in plan view, and more preferably cover the entire surface of the thin glass plate.

<Characteristics of the first and second resin layers included in the first laminate>
In the first laminate, both the first resin layer and the second resin layer have a breaking energy of ¹ mJ/mm3 or more and a storage elastic modulus at 25°C of 2500 MPa or less. is preferred. When the breaking energy is 1 mJ/mm ³ or more, sufficient impact resistance can be imparted to the thin glass that is thinned to realize a foldable electronic device. The breaking energy is more preferably 1.5 mJ/mm ³ or more, still more preferably 2 mJ/mm ³ or more. Although the upper limit of the breaking energy is not particularly limited, it is, for example, 50 mJ/mm ³ or less from the viewpoint of ensuring other properties of the laminate. Moreover, sufficient impact resistance can be provided to thin glass as the said storage elastic modulus is 2500 MPa or less. Moreover, since the flexibility of the resin layer can be ensured, the laminate can have the flexibility required for realizing a foldable electronic device. The storage elastic modulus is more preferably 2000 MPa or less, still more preferably 1800 MPa or less. Although the lower limit of the storage elastic modulus is not particularly limited, it is, for example, 100 MPa or more from the viewpoint of ensuring the impact resistance of the laminate.

The breaking energy can be measured according to JIS K7113 "Plastic tensile test method" using a test piece prepared according to the following procedure.
A release-treated polyethylene terephthalate resin film was placed on a glass plate with a thickness of 0.7 mm, with the release surface facing upward, and a silicon with a thickness of 0.5 mm was punched into a dumbbell shape (SDK-400). Install the sheet mold. The resin composition used for forming the resin layer was poured into a dumbbell mold, and the resin liquid was covered with the release surface of the release-treated polyethylene terephthalate resin film so as not to entrain air bubbles. Stack the glass plates. Next, an ultraviolet LED with a wavelength of 365 nm and an illuminance of 100 mW/cm ² is used as a light source, and exposed through the glass plate for 15 seconds to irradiate with ultraviolet rays of 1500 mJ/cm ² . Furthermore, while being sandwiched between the glass plates, it is turned over, and the same ultraviolet rays are applied again from the back side. Thereafter, the resin is cured by heating in an oven at 80° C. for 30 minutes, and the cured resin is removed from the silicon sheet mold to obtain a test piece. This test piece is subjected to a tensile test using a tensile tester. The tensile test is performed at a distance between chucks of 25 mm, a tensile speed of 50 mm/min, and a sampling interval of 20 μm until the test piece breaks. From the obtained measurement results, stress (unit: MPa) is taken on the vertical axis and strain (unit: %) is taken on the horizontal axis - Create a strain curve, this stress - surrounded by the strain curve and the horizontal axis The breaking energy can be calculated by finding the area of the portion where the fracture occurs.

In addition, the storage elastic modulus was measured by punching out a rectangular shape with a width of 5 mm and a length of 50 mm instead of a silicon sheet mold with a thickness of 0.5 mm punched into a dumbbell shape (SDK-400). Except for using a 0.5 mm silicon sheet mold, a measurement sample is prepared in the same manner as in the measurement of the breaking energy. For the prepared measurement sample, using a viscoelastic spectrometer (for example, DVA-200 manufactured by IT Instrument Control Co., Ltd.), under the conditions of 5 ° C./min and 1 Hz in the slow heating shear deformation mode, -50 ° C. to 200 ° C. It can be obtained as a storage modulus at 25° C. when the dynamic viscoelasticity spectrum of is measured.

The Young's modulus of the first resin layer and the second resin layer is preferably 1500 MPa or less. When the Young's modulus is 1500 MPa or less, it is possible to obtain appropriate flexibility of the first resin layer and the second resin layer. In addition, when the glass is broken, the resin layer is difficult to break at the same time, and a scattering prevention effect can be obtained. The Young's modulus is more preferably 1400 MPa or less, still more preferably 1300 MPa or less. Although the lower limit of the Young's modulus is not particularly limited, it is preferably 50 MPa or more from the viewpoint of ensuring the impact resistance of the laminate. The Young's modulus can be calculated by creating a stress-strain curve in the same manner as in the measurement of the breaking energy, and determining the slope of the stress-strain curve at a strain of 0 to 10%.

<Characteristics of the first and second resin layers included in the second laminate>
In the second laminate, both 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. When the Young's modulus is 50 MPa or more and 1500 MPa or less, a moderate flexibility for realizing a foldable electronic device can be obtained, and a thin glass thinned to realize a foldable electronic device. Sufficient impact resistance can be imparted. The Young's modulus is more preferably 1400 MPa or less, still more preferably 1300 MPa or less, and more preferably 80 MPa or more.

Each of the first resin layer and the second resin layer preferably has a breaking energy of 1 mJ/mm ³ or more. When the breaking energy is 1 mJ/mm ³ or more, the impact resistance of the laminate can be further improved. The breaking energy is preferably 1.5 mJ/mm ³ or more, more preferably 2 mJ/mm ³ or more. Although the upper limit of the breaking energy is not particularly limited, it is, for example, 50 mJ/mm ³ or less from the viewpoint of ensuring other properties of the laminate.

At least one of the first resin layer and the second resin layer preferably has a storage modulus at 25° C. of 3000 MPa or less, more preferably 2500 MPa or less, and even more preferably 2000 MPa or less. , 1800 MPa or less, particularly preferably 1500 MPa or less. By setting the storage elastic modulus within the above range, the flexibility of the resin layer can be improved, which is preferable for a laminate having the flexibility required for realizing a foldable electronic device. . In addition, the lower limit of the storage elastic modulus is not particularly limited, but from the viewpoint of ensuring the impact resistance of the laminate, it is preferably 10 MPa or more, more preferably 100 MPa or more, and further preferably 500 MPa or more. preferable. From the viewpoint of improving the bendability of the laminate, it is preferable that both the first resin layer and the second resin layer have a storage elastic modulus at 25° C. of 2500 MPa or less. From the viewpoint of ensuring the impact resistance of the laminate, it is preferable that both the first resin layer and the second resin layer have a storage elastic modulus of 100 MPa or more at 25°C.

<Characteristics of first and second resin layers common to first and second laminates>
It is preferable that each of the first resin layer and the second resin layer has an elongation at break of 5% or more. When the elongation at break is 5% or more, cracks and whitening are less likely to occur in a bending endurance test. More preferably, the elongation at break is 7% or more. There is no particular upper limit for the elongation at break, but from the viewpoint of ensuring the impact resistance of the laminate, it is preferably 1000% or less. As the elongation at break, a tensile test is performed in the same manner as in the measurement of the breaking energy, and the value of the strain when the test piece breaks can be used.

It is preferable that each of the first resin layer and the second resin layer has a breaking strength of 5 MPa or more and 50 MPa or less. When the breaking strength is within the range of 5 MPa or more and 50 MPa or less, it becomes easy to impart sufficient impact resistance to the thin glass. More preferably, the breaking strength is 10 MPa or more and 40 MPa or less. For the breaking strength, a tensile test is performed in the same manner as in the measurement of the breaking energy, and the value of the stress when the test piece breaks can be used.

Each of the first resin layer and the second resin layer preferably has a glass transition temperature of 100° C. or less, and at least one of the first resin layer and the second resin layer has a glass transition temperature of is preferably 100° C. or lower. When the glass transition temperature of the resin layer is 100° C. or less, the flexibility of the resin layer can be ensured. preferable. The glass transition temperature is more preferably 80° C. or lower, still more preferably 60° C. or lower. The lower limit of the glass transition temperature is not particularly limited, but is, for example, 0° C. or higher from the viewpoint of ensuring other properties of the laminate. As for the glass transition temperature, a dynamic viscoelastic spectrum is prepared in the same manner as in the measurement of the storage elastic modulus, and the temperature at which the loss tangent has a maximum value can be used.

Each of the first resin layer and the second resin layer preferably has a total light transmittance of 80% or more. When the total light transmittance of the resin layer is 80% or more, the transparency of the resin layer can be ensured. It is preferable to form a laminate. The total light transmittance is more preferably 90% or more. The total light transmittance can be measured using, for example, HazeMeter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The above total light transmittance is measured by a method conforming to JIS K 7361-1.

It is preferable that each of the first resin layer and the second resin layer has a thickness of 5 μm or more. When the thickness of the resin layer is 5 μm or more, the flexible resin layer can exert a shock absorbing function, and the thin glass thinned to realize a foldable electronic device has sufficient shock resistance. You can give it character. The thicknesses of the first resin layer and the second resin layer are 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, but from the viewpoint of ensuring the bendability of the laminate, it is preferable that they are thinner than the thin plate glass. , preferably 100 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less, particularly preferably 25 μm or less, most preferably 20 μm or less. From the viewpoint of ensuring the bendability of the laminate, it is preferable that at least one of the first resin layer and the second resin layer have a thickness of 25 μm or less.

Materials that can be used for the first resin layer and the second resin layer are described below.
The resin composition used to form 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 within a desired range. For example, one containing a cationic curable resin is preferably used because of its excellent adhesion to glass. That is, it is preferable that each of the first resin layer and the second resin layer contains a cationic curable resin polymer, and at least one of the first resin layer and the second resin layer contains a cationic It preferably contains a polymer of a curable resin.

The cationic curable resin is not particularly limited as long as it has at least one cationic polymerizable functional group in the molecule and is highly cationic polymerizable.
Examples of the cationic polymerizable functional group include epoxy group, oxetanyl group, vinyl ether group, episulfide group, and ethyleneimine group. Among them, epoxy resins, oxetane resins, and vinyl ether resins are suitable as the cationic curable resin. Since the epoxy resin has excellent adhesion to the thin plate glass, the first resin layer and the second resin layer are peeled off when the first laminate or the second laminate is repeatedly bent. can be suppressed.

The epoxy resin (epoxy group-containing compound) is not particularly limited. Novolac type epoxy resin; resorcinol type epoxy resin, and aromatic epoxy resin such as trisphenol methane triglycidyl ether; alicyclic epoxy resin; naphthalene type epoxy resin; fluorene type epoxy resin; dicyclopentadiene type epoxy resin; epoxy resins; NBR-modified epoxy resins; CTBN-modified epoxy resins; and hydrogenated products thereof. Examples of the alicyclic epoxy resin include 3′,4′-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, ε-caprolactone-modified 3′,4′-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate , bis(3,4-epoxycyclohexyl) adipate, 1,2-epoxy-4-vinylcyclohexane, 1,4-cyclohexanedimethanol diglycidyl ether, epoxyethyldivinylcyclohexane, diepoxyvinylcyclohexane, 1,2,4- Examples include triepoxyethylcyclohexane, limonene dioxide, and alicyclic epoxy group-containing silicone oligomers. These epoxy resins may be used alone or in combination of two or more.

The above-mentioned epoxy resin may be an epoxy resin that is liquid at normal temperature, or an epoxy resin that is solid at normal temperature, and these may be used in appropriate combination.
Examples of the epoxy resins that are liquid at room temperature include "EPICLON 840", "EPICLON 840-S", "EPICLON 850", "EPICLON 850-S", and "EPICLON EXA-850CRP" (manufactured by DIC Corporation). Bisphenol A type epoxy resin; "EPICLON 830", "EPICLON 830-S", "EPICLON EXA-830CRP", "EPICLON EXA-830LVP" (manufactured by DIC Corporation), "jER 806H" (manufactured by Mitsubishi Chemical Corporation) Bisphenol F type epoxy resins such as; Naphthalene type epoxy resins such as "EPICLON HP-4032" and "EPICLON HP-4032D" (manufactured by DIC Corporation); "jER XY8000" and "jER YX8034" (manufactured by Mitsubishi Chemical Corporation ), "EPICLON EXA-7015" (manufactured by DIC Corporation), "EX-252" (manufactured by Nagase ChemteX Corporation) and other hydrogenated bisphenol A type epoxy resins; "EX-201" (manufactured by Nagase ChemteX Corporation), etc. resorcinol-type epoxy resin; "Celoxide 2081", "Celoxide 2021P", "Celoxide 2000", "Celoxide 3000", "Celoxide 8000", "Celoxide 8010", "EHPE3150" (manufactured by Daicel Corporation), "TTA21" (manufactured by Jiangsu TetraChem), "Rikaresin DME-100" (manufactured by New Japan Chemical Co., Ltd.), "X-40-2670", "X-22-169AS", "X-22-169B" (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like are available as commercial products.

Examples of epoxy resins that are solid at room temperature include bisphenol A type epoxy resins such as "EPICLON 860", "EPICLON 10550", and "EPICLON 1055" (manufactured by DIC Corporation); ); Bisphenol S type epoxy resins such as "EPICLON EXA-1514" (manufactured by DIC); "EPICLON HP-4700", "EPICLON HP-4710", "EPICLON HP-4770" (above Naphthalene type epoxy resins such as "EPICLON HP-7200 series" (manufactured by DIC); dicyclopentadiene type epoxy resins such as "EPICLON HP-5000" and "EPICLON EXA-9900" available as commercial products.

Examples of the oxetane resin (oxetanyl group-containing compound) which is the cationic curable resin include 3-ethyl-3-[(2-ethylhexyloxy)methyl]oxetane, 3-ethyl-3-hydroxymethyloxetane, 1 , 4-bis([(3-ethyl-3-oxetanyl)methoxy]methyl)benzene, 3-ethyl-3-(phenoxymethyl)oxetane, bis[(3-ethyloxetan-3-yl)methyl]ether, 3 -ethyl-3-([3-(triethoxysilyl)propoxy]methyl)oxetane, oxetanylsilsesquioxane and the like. Examples of the oxetane resin include "Aron oxetane OXT-101", "Aron oxetane OXT-121", "Aron oxetane OXT-211", "Aron oxetane OXT-221", and "Aron oxetane OXT-610" (above, (manufactured by Toagosei Co., Ltd.) and the like are available as commercial products. These can be used individually by 1 type or in combination of 2 or more types.

Examples of vinyl ether resins (vinyl ether group-containing compounds) that are cationic curable resins include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, allyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, and 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, hexa decyl 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 di Methanol monovinyl ether, trimethylolpropane monovinyl ether, ethylene oxide-added trimethylolpropane monovinyl ether, pentaerythritol monovinyl ether, ethylene oxide-added pentaerythritol monovinyl ether, cyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, cyclohexylethyl vinyl ether, men Tyl vinyl ether, tetrahydrofurfuryl vinyl ether, norbornenyl vinyl ether, 1-adamantyl vinyl ether, 2-adamantyl vinyl ether, phenyl 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 Examples include trivinyl ether, pentaerythritol tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, ditrimethylolpropane tetravinyl ether, and dipentaerythritol hexavinyl ether. These can be used individually by 1 type or in combination of 2 or more types.

The method of forming the first resin layer and the second resin layer is not particularly limited. can be formed. The method of applying the resin composition is not particularly limited, and for example, a screen printing method, a die coat printing method, an offset printing method, a gravure printing method, an inkjet printing method, or the like may be used.

An electronic device comprising the laminate of the present invention is also one aspect of the present invention. As the electronic device of the present invention, a foldable electronic device (foldable electronic device) is preferable, and a foldable display device (foldable display) is particularly preferable. Specifically, for example, mobile display terminals such as smartphones, electronic books, and tablet PCs are included. The display device including the first laminate or the second laminate preferably has a configuration in which the first resin layer is arranged on the viewing side and the second resin layer is arranged on the display device side.

Furthermore, the resin composition used for forming the resin layer of the laminate of the present invention is also one aspect 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 an adherend such as glass.

The resin composition may contain a solvent from the viewpoint of coatability and the like. As the solvent, a nonpolar solvent having a boiling point of 200° C. or lower or an aprotic polar solvent having a boiling point of 200° C. or lower is preferable from the viewpoint of coatability, storage stability, and the like. Examples of the nonpolar solvent having a boiling point of 200° C. or lower or the aprotic polar solvent having a boiling point of 200° C. or lower include ketone solvents, ester solvents, hydrocarbon solvents, halogen solvents, ether solvents, and nitrogen-containing solvents. system solvents and the like. The boiling point of the nonpolar solvent or aprotic polar solvent is more preferably in the range of 80°C to 180°C from the viewpoints of stability of the coating liquid, uniformity of the coating film, drying efficiency, and the like.

The resin composition preferably has a viscosity of 1 to 1000 mPa·s at 25° C. using an E-type viscometer. A more preferable range of the above viscosity is adjusted by the coating method. For example, a range of 5 to 50 mPa s is preferable for coating by an inkjet method, a range of 10 to 100 mPa s is preferable for coating by a slit coating method, and a range of 100 to 1000 mPa s is preferable for coating by a roll coating method or an offset printing method. is preferred. On the other hand, when the viscosity exceeds 1000 mPa·s, the leveling property of the coating liquid tends to deteriorate, and the uniformity of the thickness of the coating film tends to deteriorate.
In addition, the above viscosity is determined, 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 as appropriate from the optimum torque number in each viscosity region. can be measured by selecting

A cover glass comprising the laminate of the present invention is also one aspect of the present invention. The cover glass of the present invention is preferably a protective glass arranged so as to cover an article to be protected, and more preferably a display cover glass in which the article to be protected is a display device.

ADVANTAGE OF THE INVENTION According to this invention, the laminated body excellent in impact resistance can be provided. Further, according to the present invention, it is possible to provide an electronic device and a cover glass using the laminate, and a resin composition used for forming the resin layer of the laminate.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows an example of a structure of the laminated body of this invention.

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples.

(Examples 1 to 5, Comparative Examples 1 to 3)
A curable resin shown in (1) below and an initiator shown in (2) below were stirred and mixed according to the compounding ratio shown in Table 1 below to obtain a resin composition. The resulting resin composition was diluted with propylene glycol monomethyl ether acetate as a solvent to adjust the viscosity, and coated on a thin plate glass having a thickness of 50 μm so that the thickness after drying was 10 μm. The obtained coating film was dried at a temperature of 100° C. for 15 minutes, irradiated with ultraviolet rays having a wavelength of 365 nm at an irradiation dose of 1500 mJ/cm ² , and further cured by heating at 80° C. for 30 minutes. As a result, a laminate was obtained in which a resin layer made of a cured resin material was formed on one side of the thin plate glass.

(1) Curing resin EPICON EXA-830LVP (mixture of bisphenol F type liquid epoxy resin and bisphenol A type liquid epoxy resin, manufactured by DIC)
・ JER YX7400 (polyether skeleton liquid epoxy resin, manufactured by Mitsubishi Chemical Corporation)
・ JER 4005P (bisphenol F type solid epoxy resin, manufactured by Mitsubishi Chemical Corporation)
・ JER 806H (bisphenol F type liquid epoxy resin, manufactured by Mitsubishi Chemical Corporation)
- Celoxide 2021P (3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate, manufactured by Daicel Corporation)
・ETRENACOLL EHO (3-ethyl-3-hydroxymethyloxetane, manufactured by Ube Industries, Ltd.)

(2) Initiator CPI-210S (triarylsulfonium salt type photocationic polymerization initiator, San-Apro Co., Ltd.)

(Comparative Example 4)
A thin glass sheet of Comparative Example 4 was prepared from a thin glass sheet having a thickness of 50 μm, which was the same as that of Examples 1 to 5 and Comparative Examples 1 to 3, on which no resin layer was formed.

<Physical property measurement>
The physical properties of cured resin products prepared using the resin compositions of Examples 1 to 5 and Comparative Examples 1 to 3 were measured by the following methods. Table 1 shows the results.

(Storage modulus and glass transition temperature)
A test piece of the cured resin was laminated to a thickness of 1 mm to prepare a measurement sample. Using a viscoelastic spectrometer (DVA-200, manufactured by IT Keisoku Co., Ltd.), the prepared measurement sample was subjected to dynamics from -50°C to 200°C under the conditions of 5°C/min and 1Hz in a low-speed heating shear deformation mode. A viscoelastic spectrum was measured. The storage modulus at 25°C was calculated from the obtained dynamic viscoelasticity spectrum. The temperature at which the loss tangent has a maximum value was taken as the glass transition temperature Tg (°C).

(Young's modulus, elongation at break, strength at break, energy at break)
According to JIS K7113 "Plastic tensile test method", a dumbbell-shaped (SDK-400) test piece of a cured resin having a thickness of 0.5 mm was prepared and subjected to a tensile test using a tensile tester. The tensile test was carried out at a chuck-to-chuck distance of 20 mm, a tensile speed of 50 mm/min, and a sampling interval of 20 μm until the test piece broke. From the obtained measurement results, a stress-strain curve was created in which the vertical axis represents stress (unit: MPa) and the horizontal axis represents strain (unit: %). The value of the strain when the test piece broke was defined as the elongation at break, and the value of the maximum stress when the test piece was broken was defined as the breaking strength. Young's modulus was calculated by determining the slope of the stress-strain curve at strains between 0 and 10%. The breaking energy was calculated by finding the area enclosed by the stress-strain curve and the horizontal axis.

<Evaluation>
The laminates obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and the thin plate glass of Comparative Example 4 were evaluated as follows. Table 1 shows the results.

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

(Pen drop test)
The laminate is placed with the thin glass side facing upward on a 10 mm thick SUS plate, and a ballpoint pen (manufactured by BIC Japan, orange EG 0.7, pen tip 0.7 mmφ, weight 5.75 g) is placed with the pen tip It was vertically dropped from a predetermined height downward onto the glass surface of the laminate. The maximum height at which cracks did not occur in the thin plate glass was taken as the test result.

(Scattering prevention test)
Regarding the laminate in which cracks occurred in the thin plate glass in the pen drop test, the scattering prevention property was evaluated based on the following evaluation criteria.
Good: Cracks were generated in the glass, but the pieces of glass separated by the cracks were held together by the resin layer, and there was no separation between the resin layer and the thin sheet glass, and no scattering of the glass was observed.
x: Cracking occurred in the resin layer simultaneously with the occurrence of cracks in the thin plate glass, resulting in singulation, or separation of the resin layer and the thin glass plate resulted in singulation of the glass.

(Bending endurance test)
Using a U-shaped bending tester (manufactured by Yuasa System Co., Ltd., DLDMLH-FS), the laminate was bent so that the thin sheet glass was arranged inside, and the test speed was 2 seconds/times, and the bending diameter was R3. It was repeatedly bent at 0 mm and 100,000 times of bending. Then, in a state in which the laminate was arranged on the movable plate in a horizontal state, both movable plates were turned by 90 degrees to bend the laminate into a U-shape. After the test, the appearance of the laminate was visually confirmed. "○○" when there was no change in appearance before and after the test, "○" when cracks or whitening occurred at the edge after the test, but no cracks or whitening occurred at other than the edge after the test, and "○" after the test A case where the appearance changed due to cracks or whitening was evaluated as "x".

(Examples 6 to 12)
A curable resin shown in (1) below and an initiator shown in (2) below were stirred and mixed according to the compounding ratio shown in Table 2 below to obtain a resin composition. The resulting resin composition was diluted with propylene glycol monomethyl ether acetate as a solvent to adjust the viscosity, and coated on a thin plate glass having a thickness of 50 μm so as to have a thickness after drying as shown in Table 2 below. The obtained coating film was dried at a temperature of 100° C. for 15 minutes, irradiated with ultraviolet rays having a wavelength of 365 nm at an irradiation dose of 1500 mJ/cm ² , and further cured by heating at 80° C. for 30 minutes. As a result, a laminate provided with a first resin layer made of a cured resin on one side (visible side) of the thin plate glass and a second resin layer made of a cured resin on the other side (display element side) was gotten.

(1) Curing resin EPICON EXA-830LVP (mixture of bisphenol F type liquid epoxy resin and bisphenol A type liquid epoxy resin, manufactured by DIC)
・ JER YX7400N (polyether skeleton liquid epoxy resin, manufactured by Mitsubishi Chemical Corporation)
・ JER 4005P (bisphenol F type solid epoxy resin, manufactured by Mitsubishi Chemical Corporation)
・ JER YX8034 (hydrogenated bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation)
- Celoxide 2021P (3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate, manufactured by Daicel Corporation)
・ETRENACOLL EHO (3-ethyl-3-hydroxymethyloxetane, manufactured by Ube Industries, Ltd.)

(2) Initiator CPI-210S (triarylsulfonium salt type photocationic polymerization initiator, San-Apro Co., Ltd.)
・ DTS-200 (aromatic sulfonium salt type photocationic polymerization initiator, manufactured by Midori Chemical Co., Ltd.)
(3) Surface modifier BYK-340 (manufactured by Big Chemie)

<Physical property measurement>
Physical properties of cured resins produced in Examples 6 to 12 were measured by the following methods. The results are shown in Table 2 below.

(Storage modulus and glass transition temperature)
A test piece of a cured resin having a thickness of 0.5 mm, a width of 5 mm, and a length of 50 mm was prepared, and a viscoelastic spectrometer (DVA-200, manufactured by IT Keisoku Co., Ltd.) was used at a tensile mode of 10 ° C./min. A dynamic viscoelastic spectrum was measured from -50°C to 150°C under the condition of 10Hz. The storage modulus at 25°C was determined from the obtained dynamic viscoelasticity spectrum. The temperature at which the loss tangent has a maximum value was taken as the glass transition temperature Tg (°C).

<Evaluation>
The thin glass sheets of the laminates obtained in Examples 6 to 12 were evaluated as follows. The results are shown in Table 2 below.

(Pen drop test)
The first resin layer side of the laminate is placed facing upward on an artificial marble plate (manufactured by DuPont, "Corian") having a thickness of 10 mm, and a ballpoint pen (manufactured by BIC Japan, orange EG 0.7, nib 0) is applied. 0.7 mmφ, weight 5.75 g) was vertically dropped from a predetermined height toward the surface of the laminate on the first resin layer side with the pen tip facing downward. The maximum height at which cracks did not occur in the thin plate glass was taken as the test result.

(Scattering prevention test)
Regarding the laminate in which cracks occurred in the thin plate glass in the pen drop test, the scattering prevention property was evaluated based on the following evaluation criteria.
Good: Cracks were generated in the glass, but the pieces of glass separated by the cracks were held together by the resin layer, and there was no separation between the resin layer and the thin sheet glass, and no scattering of the glass was observed.
x: Cracks were generated in the resin layer simultaneously with the occurrence of cracks in the thin plate glass, and the glass was singulated by separation of the resin layer and the thin plate glass.

(Bending endurance test)
Using a U-shaped bending tester (manufactured by Yuasa System Co., Ltd., DLDMLH-FS), the laminate is arranged so that the first resin layer is on the inside when bending, and the test speed is 1 second / time, bending It was repeatedly bent with a diameter R of 2.0 mm and a bending number of 100,000 times. After the test, the bent portion of the laminate was visually confirmed. "○○" when there was no change in appearance before and after the test, "○" when cracks or whitening occurred at the edge after the test, but no cracks or whitening occurred at other than the edge after the test, and "○" after the test A case where the appearance changed due to cracks or whitening was evaluated as "x".

REFERENCE SIGNS LIST 10 laminate 11 first resin layer 12 thin plate glass 13 second resin layer 14 optical transparent adhesive 15 polarizing plate

Claims

A thin glass sheet having a thickness of 200 μm or less and a resin layer having a thickness of 5 μm or more disposed on at least one side of the thin glass sheet,
A laminate, wherein the resin layer has a breaking energy of 1 mJ/mm 3 or more and a storage elastic modulus of 2500 MPa or less at 25°C.
2. The laminate according to claim 1, wherein 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, wherein the resin layer has a storage modulus at 25[deg.] C. of 2000 MPa or less.
4. The laminate according to claim 1, 2 or 3, wherein the resin layer has a glass transition temperature of 100[deg.] C. or less.
5. The laminate according to claim 1, 2, 3 or 4, wherein the resin layer contains a cationic curable resin polymer.
a first resin layer having a thickness of 5 μm or more, which is arranged on one side of the thin plate glass;
a second resin layer having a thickness of 5 μm or more, which is arranged on the side opposite to the first resin layer side of the thin plate glass;
The laminate according to claim 1, wherein both the first resin layer and the second resin layer have a breaking energy of 1 mJ/mm3 or more and a storage elastic modulus at 25°C of 2500 MPa or less.
7. The laminate according to claim 6, wherein both the first resin layer and the second resin layer have a Young's modulus of 50 MPa or more and 1500 MPa or less.
A thin glass sheet having a thickness of 200 μm or less and a resin layer having a thickness of 5 μm or more disposed on at least one side of the thin glass sheet,
A laminate, wherein the Young's modulus of the resin layer is 50 MPa or more and 1500 MPa or less.
The laminate according to claim 8, wherein the resin layer has a breaking energy of 1 mJ/mm3 or more.
The laminate according to claim 8 or 9, wherein the resin layer has a storage elastic modulus at 25°C of 2500 MPa or less.
11. The laminate according to claim 8, 9 or 10, wherein the resin layer has a glass transition temperature of 100[deg.] C. or lower.
12. The laminate according to claim 8, 9, 10 or 11, wherein the resin layer contains a cationic curable resin polymer.
a first resin layer having a thickness of 5 μm or more, which is arranged on one side of the thin plate glass;
a second resin layer having a thickness of 5 μm or more, which is arranged on the side opposite to the first resin layer side of the thin plate glass;
9. The laminate according to claim 8, wherein both the first resin layer and the second resin layer have a Young's modulus of 50 MPa or more and 1500 MPa or less.
14. The laminate according to claim 13, wherein at least one of the first resin layer and the second resin layer has a storage elastic modulus at 25[deg.]C of 3000 MPa or less.
15. The laminate according to claim 6, 7, 13 or 14, wherein at least one of the first resin layer and the second resin layer has a thickness of 25 [mu]m or less.
16. The laminate according to claim 6, 7, 13, 14 or 15, wherein at least one of said first resin layer and said second resin layer has a glass transition temperature of 100[deg.] C. or less.
17. The laminate according to claim 6, 7, 13, 14, 15 or 16, wherein at least one of the first resin layer and the second resin layer contains a cationic curable resin polymer.
An electronic device comprising the laminate according to any one of claims 1 to 17.
A resin composition used for forming a resin layer of the laminate according to any one of claims 1 to 17.
A cover glass comprising the laminate according to any one of claims 1 to 17.