Laminate for display device, display device, and display device with support plate

Abstract

The present disclosure provides a laminate for a display device, comprising: a resin substrate; a hard coat layer disposed on one surface of the resin substrate; and a resin layer disposed on the surface of the resin substrate on the opposite side from the hard coat layer, the cross-sectional indentation amount of the resin layer being 200-3000 nm inclusive, the cross-sectional indentation amount of the resin substrate being smaller than the cross-sectional indentation amount of the resin layer, and the thickness of the resin layer being 5-45 [mu] m inclusive. The total thickness of the resin substrate and the resin layer is 50 [mu] m or more and 130 [mu] m or less.

Description

Technical Field

[0001] The present disclosure relates to a laminate for a display device, a display device, and a display device with a support plate. Background Art

[0002] On the surface of the display device, a display device laminate having various properties such as hard coating, abrasion resistance, antireflection, antiglare, antistatic, and antifouling properties is disposed as a front panel.

[0003] As such a laminate for a display device, for example, Patent Document 1 discloses a laminate for a display device, which has an impact absorbing layer, a support body and a functional layer, wherein the film thickness of the impact absorbing layer is greater than 1 μm, and the maximum value of the ratio (tan δ) of the loss modulus of the impact absorbing layer at 25° C. to the storage modulus in the frequency range of 10 to 105 Hz is less than 2.0.

[0004] On the other hand, in recent years, flexible display devices such as foldable displays, rollable displays, bendable displays, and slidable displays have attracted attention, and the development of display device laminates arranged on the surface of flexible display devices is becoming popular. Among them, slidable displays can expand the size of the screen by sliding the display, and have attracted particular attention in recent years.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2021-14014 Summary of the invention

[0008] Problems to be solved by the invention

[0009] The display device laminate disposed on the surface of the flexible display device requires scratch resistance. Therefore, it is considered to use a display device laminate having a hard coating layer. For a foldable display in a flexible display device, it is required that there will be no display defects even if it is bent repeatedly, and the display device laminate disposed on the surface of the flexible display device requires bending resistance without peeling or cracking when it is bent repeatedly.

[0010] On the other hand, when a display device laminate having a hard coat layer is used in a slidable display or a rollable display, the following inconvenience may occur, which is different from that of a foldable display.

[0011] Figure 2 (a) is a schematic front view of a smartphone with a slidable display, Figure 2 (b) and Figure 2 (c) is Figure 2(a) AA schematic cross-sectional view. Figure 2 The illustrated smartphone 20 has a caterpillar structure X for sliding a slidable display 21 stored inside the device to be sent toward the viewer when the screen is expanded, and for sliding the slidable display 21 to be stored inside the device when the screen is reduced.

[0012] Figure 3 A partially enlarged view showing the track structure X. Specifically, the slidable display 21 can slide in a state where it is arranged on a support plate S (for example, made of SUS). The support plate S has a straight through pattern P with a length direction perpendicular to the screen expansion direction in the area that becomes the bending portion, so that it is easy to bend. With respect to the track structure X, in general, the slidable display 21 is bent in such a way that the stacked body for the display device, which is the surface material, becomes the outside. In addition, since the support plate S has the through pattern P, there is a height difference with a high curvature locally. The height difference of the support plate will affect the stacked body for the display device, which is the surface material of the display device.

[0013] Therefore, when the laminated body for display device having a hard coat layer is used as a surface material for a slidable display or a rollable display, for example Figure 4 and Figure 5 As shown, in the curved portion (hereinafter sometimes referred to as a sliding curved portion or sliding curved portion) in the track structure X of the display device stack, cracks sometimes occur in the hard coating layer, or floating sometimes occurs in the adhesive layer between the display panel and the support plate configured with the display device stack.

[0014] The present disclosure has been made in view of the above-mentioned actual situation, and a main object of the present disclosure is to provide a laminate for a display device having excellent scratch resistance and suppressing the defect of a sliding bending portion.

[0015] Means for solving problems

[0016] One embodiment of the present disclosure provides a stacked body for a display device, comprising: a resin substrate; a hard coating layer disposed on one surface of the resin substrate; and a resin layer disposed on the surface of the resin substrate opposite to the hard coating layer, wherein a cross-sectional indentation meter indentation amount of the resin layer is greater than 200 nm and less than 3000 nm, a cross-sectional indentation meter indentation amount of the resin substrate is less than a cross-sectional indentation meter indentation amount of the resin layer, a thickness of the resin layer is greater than 5 μm and less than 45 μm, and a total thickness of the resin substrate and the resin layer is greater than 50 μm and less than 130 μm.

[0017] Another embodiment of the present disclosure provides a display device including a display panel and the display device laminated body arranged on the viewer side of the display panel, wherein the display device laminated body is arranged so that the hard coating layer side becomes the viewer side.

[0018] Another embodiment of the present disclosure provides a display device with a support plate, which has the above-mentioned display device and a support plate arranged on the surface of the above-mentioned display panel side of the above-mentioned display device. The above-mentioned display device is a flexible display, and the above-mentioned support plate has a through pattern penetrating in the thickness direction.

[0019] Effects of the Invention

[0020] The present disclosure exerts an effect of being able to provide a laminate for a display device having excellent scratch resistance and suppressing the failure of a sliding bent portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic cross-sectional view illustrating a laminate for a display device in the present disclosure.

[0022] Figure 2 (a) is a schematic front view of a smart phone with a slidable display, Figure 2 (b) and Figure 2 (c) is Figure 2 (a) AA schematic cross-sectional view.

[0023] Figure 3 This is a partial enlarged view of the crawler structure.

[0024] Figure 4 This is a schematic cross-sectional view showing an example of a conventional laminate for a display device.

[0025] Figure 5 This is a schematic cross-sectional view showing an example of a conventional laminate for a display device.

[0026] Figure 6 This is a schematic diagram for explaining a sliding bending test.

[0027] Figure 7 is a schematic top view of a support plate used for a sliding bending test.

[0028] Figure 8 is a schematic cross-sectional view illustrating a display device of the present disclosure.

[0029] Fig. 9 is a schematic cross-sectional view illustrating a display device of the present disclosure.

[0030] Fig.10 This is a schematic cross-sectional view showing an example of a display device with a support plate in the present disclosure. DETAILED DESCRIPTION

[0031] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings, etc. Among them, the present disclosure can be implemented in a variety of different ways, and is not to be construed as being limited to the contents of the embodiments illustrated below. In addition, in order to make the description clearer, the drawings sometimes schematically represent the width, thickness, shape, etc. of each part compared to the actual situation, but this is always an example and does not limit the interpretation of the present disclosure. In addition, in this specification and the drawings, the same figure marks are given to the same elements as the above-mentioned elements in the drawings that have already appeared, and the detailed description is appropriately omitted.

[0032] In this specification, when describing a method of arranging another member above a certain member, if it is described only as "above" or "below", unless otherwise stated, it includes both the case where the other member is arranged directly above or directly below in a manner of contacting with the certain member, and the case where the other member is arranged above or below the certain member with another member further between them. In addition, in this specification, when describing a method of arranging another member on the surface of a certain member, if it is described only as "surface side" or "surface", unless otherwise stated, it includes both the case where the other member is arranged directly above or directly below in a manner of contacting with the certain member, and the case where the other member is arranged above or below the certain member with another member further between them.

[0033] Hereinafter, the display device laminate and the display device in the present disclosure will be described in detail.

[0034] A. Laminated body for display device

[0035] Figure 1 This is a schematic cross-sectional view showing an example of a laminate for a display device in the present disclosure. Figure 1 The laminated body 10 for display device shown has a resin substrate 1, a hard coating layer 2 disposed on one surface of the resin substrate 1, and a resin layer 3 disposed on the surface of the resin substrate 1 opposite to the hard coating layer 2. In addition, the cross-sectional indentation meter indentation amount of the resin layer 3 is 200 nm or more and 3000 nm or less, and the cross-sectional indentation meter indentation amount of the resin substrate 1 is smaller than the cross-sectional indentation meter indentation amount of the resin layer 3. Furthermore, the thickness of the resin layer 3 is 5 μm or more and 45 μm or less, and the total thickness of the resin substrate 1 and the resin layer 3 is 50 μm or more and 130 μm or less.

[0036] Figure 4 (a) is a schematic cross-sectional view showing an example of a conventional laminate for a display device. Figure 4 The display device laminate 50 shown in (a) includes a resin substrate 51 and a hard coat layer 52 . Figure 4(b) is an explanatory diagram of a test piece formed by bonding a display device laminate 50 to a support plate S via an adhesive layer 53 and subjected to a sliding bending test simulating sliding bending during use of a slidable display. Figure 4 As shown in (b), in this sliding bending test, the adhesive layer 53 floats from the support plate S. It is speculated that the reason is that since the resin substrate 51 is relatively hard, it cannot follow the high curvature of the support plate S. This problem also occurs when an actual slidable display is used, and the adhesive layer between the display panel and the support plate is peeled off from the display panel.

[0037] Figure 5 (a) is a schematic cross-sectional view showing another example of a conventional laminate for a display device. Figure 5 The display device laminate 60 shown in (a) includes a resin layer 61 and a hard coat layer 62 . Figure 5 (b) is an explanatory diagram of a test piece formed by bonding a display device laminate 60 to a support plate S via an adhesive layer 63 and subjected to a sliding bending test simulating sliding bending during use of a slidable display. Figure 5 As shown in (b), in this sliding bending test, cracks are generated in the hard coating layer 62. It is speculated that the reason is that although the resin layer 61 follows the height difference of the support plate S, the hard coating layer 62 cannot follow the high curvature of the local support plate S, thereby generating cracks. This problem also occurs when the actual slidable display is used, and cracks are generated in the hard coating layer.

[0038] In contrast, in the display device laminate of the present disclosure, the resin layer disposed on one surface of the resin substrate has a thickness greater than a specified value, and thus has a cross-sectional indentation instrument indentation greater than a specified value, and thus functions as a height difference absorption layer. Therefore, the display device laminate can follow the height difference of the support plate when sliding and bending. Thus, when the display device laminate of the present disclosure is disposed on the observer side of the display panel and used as a display device, in the screen expansion area of ​​a slidable display, etc., it is possible to suppress the peeling of the adhesive layer between the display panel and the above-mentioned support plate configured by the adhesive layer on the surface of the support plate constituting the crawler structure.

[0039] In addition, since a resin substrate harder than the resin layer is provided, and the total thickness of the resin substrate and the resin layer is greater than a predetermined value, when the screen is expanded, the curvature of the high curvature region locally generated by the support plate constituting the crawler structure can be mitigated, and the high curvature can be prevented from being locally applied to the hard coating layer. Thus, the generation of cracks in the hard coating layer can be suppressed.

[0040] Furthermore, the laminated body for a display device of the present disclosure has a hard coat layer, the thickness of the resin layer is equal to or less than a predetermined value, and there is a resin substrate harder than the resin layer, and therefore has excellent scratch resistance.

[0041] In addition, the property of suppressing the above-mentioned malfunction of the sliding bending portion is sometimes referred to as sliding bending resistance.

[0042] The laminated body for display device of the present disclosure comprises a resin substrate, a hard coating layer disposed on one surface of the resin substrate, and a resin layer disposed on the surface of the resin substrate opposite to the hard coating layer. That is, the laminated body for display device of the present disclosure comprises the resin layer, the resin substrate and the hard coating layer in this order in the lamination direction.

[0043] Hereinafter, the display device stacked body of the present disclosure will be described in detail.

[0044] I. Resin layer

[0045] The resin layer used in the display device laminate of the present disclosure can absorb the height difference caused by the support plate constituting the track structure used in the screen expansion area of ​​the slidable display, etc. Thus, in the screen expansion area of ​​the slidable display, etc., it is possible to suppress the peeling between the support plate constituting the track structure and the display panel arranged on the surface of the support plate by the adhesive layer.

[0046] 1. Cross-section indentation tester penetration

[0047] The cross-sectional indentation depth of the resin layer in the present disclosure is 200 nm or more, preferably 250 nm or more, and more preferably 280 nm or more. By making the cross-sectional indentation depth of the resin layer within the above range, the height difference absorption performance can be obtained, and the floating of the adhesive layer between the display panel and the support plate can be suppressed.

[0048] On the other hand, the cross-sectional indentation depth of the resin layer is 3000 nm or less, preferably 2800 nm or less, and more preferably 2000 nm or less. By setting the cross-sectional indentation depth of the resin layer to the above range, the hardness of the hard coating surface can be maintained, and high scratch resistance can be obtained.

[0049] In the present disclosure, the cross-sectional indentation penetration of the resin layer is obtained by performing an indentation test in which the Berkovich indenter is pressed into the resin layer with a certain load and measuring the displacement d at this time. Specifically, first, a block is prepared by embedding a display device laminate cut into 1 mm × 10 mm with an embedding resin, and a uniform slice having a thickness of more than 70 nm and less than 100 nm without holes is cut from the block using a conventional slicing method. The slices are prepared using an ultrathin slicer EMUC7 of Leica Microsystems Co., Ltd. Then, the remaining block after the uniform slice without holes is cut out is used as a measurement sample. Next, in the cross section obtained by cutting out the above-mentioned slice in this measurement sample, a nanoindenter (TI950TriboIndenter manufactured by Bruker) is used, and a Berkovich indenter (triangular pyramid, TI-0039 manufactured by Bruker) is used as an indenter. Under the following measurement conditions, the indenter is vertically pressed into the center of the cross section of the resin layer with a maximum load of 200μN for 40 seconds, and the displacement (indentation depth) d at this time is measured. Here, in order to avoid the influence of the side edge of the resin layer, the Berkovich indenter is pressed into the part at a distance of more than 500nm from the two side ends of the resin layer to the center side of the resin layer. The displacement d is the arithmetic mean of the values ​​obtained by measuring 10 places. It should be noted that when the measured value contains a value that deviates from the arithmetic mean by more than ±20%, the measured value is excluded and re-measured. Whether there is a measured value deviating from the arithmetic mean by more than ±20% is determined by determining whether a value (%) calculated by (AB) / B×100 (assuming that the measured value is A and the arithmetic mean is B) is more than ±20%.

[0050] (Measurement conditions)

[0051] Control method: load control (maximum load 200μN)

[0052] Lifting amount: 0nm

[0053] Preload: 0.5μN

[0054] Loading speed: 5μN / s

[0055] Holding time under maximum load: 10 seconds

[0056] Unloading speed: 5μN / s

[0057] Temperature: 23℃

[0058] Relative humidity: 50%

[0059] 2. Total light transmittance

[0060] The total light transmittance of the resin layer used in the present disclosure is, for example, preferably 80% or more, more preferably 85% or more, and further preferably 88% or more. With such a high total light transmittance, a laminate for a display device having good transparency can be obtained.

[0061] Here, the total light transmittance of the resin layer can be measured in accordance with JIS K7361-1, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

[0062] 3. Thickness

[0063] The thickness of the resin layer in the present disclosure is 5 μm or more, preferably 10 μm or more. When the thickness is within the above range, the height difference absorption performance can be obtained.

[0064] On the other hand, from the viewpoint of accommodation in display devices such as slidable displays and rollable displays, the thickness of the resin layer is preferably thin. Specifically, it is 45 μm or less, 35 μm or less, 30 μm or less, or 25 μm or less. By making the thickness within the above range, good accommodation in the display device can be obtained, and the hardness of the hard coating surface can be maintained, so that the scratch resistance can be maintained.

[0065] 4. Material of resin layer

[0066] The material of the resin layer in the present disclosure is not particularly limited as long as the cross-sectional indentation meter indentation amount of the resin layer is within the above range and the material is transparent, and examples thereof include urethane resins, acrylic gels, silicone gels, etc. In the present disclosure, urethane resins are preferred, and ionizing radiation curable urethane resins and thermoplastic polyurethanes (TPU) are particularly preferred. Urethane resins are resins having urethane bonds.

[0067] Thermoplastic polyurethane is a polyurethane that exhibits plasticity when heated, and generally refers to a polyurethane having a linear structure with a certain degree of high molecular weight. Thermoplastic polyurethane can be obtained, for example, by copolymerization of polyisocyanate, polymer polyol and chain extender. The polyisocyanate is, for example, an aliphatic, alicyclic or aromatic diisocyanate, preferably an aromatic diisocyanate.

[0068] As the high molecular weight polyol, a polyether polyol or polyester polyol having a molecular weight of preferably 500 to 8000, more preferably 600 to 4000 is preferred. As the polyether polyol, for example, polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene oxypropylene glycol, polyoxytetramethylene glycol, polyoxyhexamethylene glycol, etc. can be cited. Among them, polyoxytetramethylene glycol is preferred. As the polyester polyol, an aliphatic polyester polyol derived from an aliphatic dicarboxylic acid and an aliphatic diol is preferred.

[0069] Ionizing radiation curable urethane resin refers to a cured product of an ionizing radiation curable urethane resin composition, wherein a cured product of an ultraviolet curable urethane resin composition is preferred. The ionizing radiation curable urethane resin composition comprises urethane (meth) acrylate. The urethane (meth) acrylate may be any one of a monomer, an oligomer and a prepolymer. The number of (meth) acryloyl groups (number of functional groups) in the urethane (meth) acrylate is preferably 2 or more and 4 or less. It should be noted that "(meth) acryloyl" refers to both "acryloyl" and "methacryloyl". The weight average molecular weight of the urethane (meth) acrylate is preferably 1500 or more and 20000 or less. The ionizing radiation curable urethane resin composition may have a (meth) acrylate compound. As the (meth) acrylate compound, monofunctional (meth) acrylate compounds and multifunctional (meth) acrylate compounds may be cited. The ionizing radiation curable urethane resin composition may contain, for example, one or both of a monofunctional (meth)acrylate compound and a polyfunctional (meth)acrylate compound. By adjusting the type and blending amount of the (meth)acrylate compound, particularly the polyfunctional (meth)acrylate compound, the cross-sectional indentation meter indentation amount of the resin layer can be adjusted.

[0070] As the acrylic gel, any polymer obtained by polymerizing monomers containing acrylic esters for use in adhesives and the like can be used, and various acrylic gels can be used. Specifically, as the acrylic gel, for example, acrylic gels obtained by polymerizing or copolymerizing acrylic monomers such as ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-hexyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, isomyristyl (meth)acrylate, lauryl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, and isostearyl (meth)acrylate can be used. In the present specification, "(meth)acrylate" means both "acrylate" and "methacrylate". It should be noted that the acrylic acid ester used in the above (co)polymerization can be used alone or in combination of two or more.

[0071] Silicone gel refers to a substance obtained by gelling silicone oil into a solid state. In particular, from the perspective of not producing reaction byproducts (exhaust), it is preferred to use a two-liquid addition reaction type silicone gel. The two-liquid addition reaction type silicone gel is obtained by a hydrosilylation reaction of a silicone polymer (main agent) having a vinyl group and a silicone polymer (curing agent) having a hydroxyl group under a platinum catalyst. As the raw material of the two-liquid addition reaction type silicone, various silicon compounds known in the past can be appropriately selected and used, and silicon compounds commercially available as various silicone materials can also be used. In addition, the substituents of the silicon atoms are not particularly limited, such as alkyl groups with 1 to 10 carbon atoms such as methyl, ethyl and propyl groups, cycloalkyl groups with 5 to 10 carbon atoms such as cyclopentyl and cyclohexyl groups, alkenyl groups with 2 to 10 carbon atoms such as vinyl and allyl groups, and aryl groups with 5 to 20 carbon atoms such as phenyl and tolyl groups. In addition, it can also be a group in which a part of the hydrogen atoms of these substituents are substituted by other atoms or substituents.

[0072] Specific examples of two-liquid reactive heat-addition silicone gels include CF-5106 (trade name: manufactured by Dow Corning Toray Co., Ltd.), KE-1012A / B (trade name: manufactured by Shin-Etsu Silicone Co., Ltd.), and XE14-685 (A) / (B) (trade name: manufactured by Momentive Co., Ltd.). These silicone gels can be used by dividing the organic silicone resin as a raw material into liquid A and liquid B and mixing the two liquids at a predetermined ratio.

[0073] The resin layer may contain ultraviolet absorbers, spectral transmittance regulators, antifouling agents, inorganic particles and / or organic particles, etc., as long as the cross-sectional indentation depth of the resin layer is within the above range and the resin layer has transparency.

[0074] 5. Method for forming resin layer

[0075] As a method for forming the resin layer in the present disclosure, for example, a method of coating a resin composition on one surface of a resin substrate via a primer layer as required can be cited. As a coating method, there is no particular limitation as long as it is a method that can be coated with a desired thickness, and general coating methods such as gravure coating, reverse gravure coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, screen printing, etc. can be cited.

[0076] As a method for forming the resin layer, a transfer method of transferring the resin layer to one side of a resin substrate or a method of laminating a film-like resin layer to one side of a resin substrate via a primer layer can be used.

[0077] II. Resin substrate

[0078] The resin substrate in the present disclosure is disposed between the resin layer and the hard coating layer, has a predetermined film thickness together with the resin layer, and is formed of a material harder than the resin layer. Therefore, the curvature of the high curvature region locally generated by the support plate constituting the crawler structure used in the screen expansion region of the slidable display etc. can be alleviated, and the high curvature can be prevented from being locally applied to the hard coating layer. Thus, the generation of cracks in the hard coating layer can be suppressed.

[0079] 1. Cross-section indentation tester penetration

[0080] The cross-sectional indentation indentation of the resin substrate in the present disclosure is smaller than the cross-sectional indentation indentation of the above-mentioned resin layer. By making the cross-sectional indentation indentation of the resin substrate smaller than the cross-sectional indentation indentation of the upper resin layer, the generation of cracks in the hard coating layer can be suppressed. The cross-sectional indentation indentation of the resin substrate is, for example, less than 200 nm, preferably less than 180 nm. The method for determining the cross-sectional indentation indentation of the resin substrate is the same as the method described in the above-mentioned "I. Resin layer".

[0081] 2. Young's modulus

[0082] The Young's modulus of the resin substrate in the present disclosure is preferably 2 GPa or more, wherein, preferably 4 GPa or more, particularly preferably 5 GPa or more. The reason is that the curvature of the high curvature region generated locally can be alleviated, and the high curvature can be prevented from being locally applied to the hard coating. It should be noted that the resin substrate uses a substrate below 12 GPa.

[0083] In the present disclosure, the Young's modulus of the resin substrate is measured by the following tensile test method. In the tensile test, first, a single-layer resin substrate layer of a size of 0.5 cm × 7 cm is cut out from the resin substrate to obtain a sample. Then, on the clamping fixture attached to the Tensilon universal testing machine (product name "RTC-1310A", manufactured by Orientec), the two ends of the sample are fixed in such a way that the length direction of the cut sample becomes the tensile direction. Next, using the above-mentioned Tensilon universal testing machine, the sample is stretched at a tensile speed of 10 mm / min at 25°C, thereby performing a tensile test. In the stress-strain curve of the resin substrate layer obtained by the above-mentioned tensile test, according to JIS K7161-4, the slope of the straight line connecting the stress when the strain is 0.05% and the stress when the strain is 0.25% is calculated, thereby calculating the Young's modulus. The Young's modulus is the arithmetic mean of the values ​​obtained by measuring 3 times.

[0084] 3. Thickness of resin substrate

[0085] The thickness of the resin substrate is not particularly limited as long as the total thickness of the resin substrate and the resin layer is within the range described below, and is, for example, 20 μm or more, 30 μm or more, or 65 μm or more. On the other hand, it is, for example, 125 μm or less, 100 μm or less, or 80 μm or less.

[0086] 4. Material of resin substrate

[0087] The resin constituting the resin substrate used in the present disclosure is not particularly limited as long as it is a resin that can obtain a resin substrate with a cross-sectional indenter indentation amount that becomes the above-mentioned cross-sectional indenter indentation amount and has transparency, and examples thereof include polyester resins, polyimide resins, cellulose resins, and the like.

[0088] In the present disclosure, polyimide resin refers to a polymer having an imide bond in the main chain. As polyimide resin, for example, polyimide, polyamide-imide, polyester-imide, polyether-imide, etc. can be cited. As polyester resin, for example, polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthalate (PEN), etc. can be cited. As cellulose resin, for example, triacetyl cellulose (TAC), etc. can be cited. Among them, polyester resin is preferred. These resins can be used alone or in combination of two or more. In the present disclosure, polyimide resin, PET, TAC, etc. are preferably used.

[0089] The resin substrate may further contain additives as required, such as ultraviolet absorbers, light stabilizers, antioxidants, inorganic particles, silica fillers for smooth winding, surfactants for improving film forming properties or degassing properties, and adhesion improvers.

[0090] III. Hard coating

[0091] The display device laminate in the present disclosure has a hard coating layer on the surface of the resin substrate opposite to the resin layer. The hard coating layer is a member for increasing the surface hardness. By configuring the hard coating layer, the scratch resistance can be improved.

[0092] The hard coat layer in the present disclosure may be a single layer or may have a multilayer structure of two or more layers.

[0093] 1. Pencil hardness

[0094] Here, the "hard coat layer" refers to a member for improving the surface hardness, and specifically refers to a member that exhibits a hardness of "H" or higher when subjected to a pencil hardness test specified in JIS K 5600-5-4 (1999) in the configuration where the display device laminated body in the present disclosure has a hard coat layer.

[0095] The pencil hardness of the surface on the hard coat layer side of the laminate for a display device in the present disclosure is preferably H or higher, more preferably 2H or higher, and further preferably 3H or higher.

[0096] Here, the pencil hardness is measured by the pencil hardness test specified in JIS K5600-5-4 (1999). Specifically, the pencil hardness test specified in JIS K5600-5-4 (1999) can be performed on the surface of the hard coating layer side of the display device laminate using a test pencil specified in JIS-S-6006, and the highest pencil hardness without damage can be evaluated. As measurement conditions, an angle of 45°, a load of 750g, a speed of 0.5mm / second or more and 1mm / second or less, and a temperature of 23±2°C can be set. As a pencil hardness tester, for example, a pencil scratch coating hardness tester manufactured by Toyo Seiki Co., Ltd. can be used.

[0097] 2. Thickness

[0098] The thickness of the hard coat layer can be appropriately selected according to the material of the hard coat layer, the function of the hard coat layer and the purpose of the display device laminate. For example, when the material of the hard coat layer is an organic material, the thickness of the hard coat layer is preferably 5 μm or more, and can also be 10 μm or more. When the thickness of the hard coat layer is above the above value, scratch resistance can be reliably obtained. On the other hand, the thickness of the hard coat layer is, for example, 20 μm or less.

[0099] In addition, for example, when the material of the hard coat layer is an inorganic material, the thickness of the hard coat layer can be approximately several tens of nanometers.

[0100] 3. Hard coating material

[0101] As the material of the hard coat layer, for example, an organic material, an inorganic material, an organic-inorganic composite material, or the like can be used.

[0102] Among them, the material of the hard coat is preferably an organic material. Specifically, the hard coat preferably comprises a cured product of a resin composition containing a polymerizable compound. The cured product of the resin composition containing a polymerizable compound can be obtained by using a polymerization initiator as needed and making the polymerizable compound undergo a polymerization reaction using a known method.

[0103] (1) Polymerizable compounds

[0104] The polymerizable compound has at least one polymerizable functional group in the molecule. As the polymerizable compound, for example, at least one of a radical polymerizable compound and a cation polymerizable compound can be used.

[0105] A free radical polymerizable compound refers to a compound having a free radical polymerizable group. The free radical polymerizable group possessed by the free radical polymerizable compound is not particularly limited as long as it is a functional group capable of undergoing free radical polymerization reaction, and examples thereof include groups containing carbon-carbon unsaturated double bonds, and specifically, vinyl, (meth) acryloyl, etc. It should be noted that when the free radical polymerizable compound has two or more free radical polymerizable groups, these free radical polymerizable groups may be the same or different.

[0106] From the viewpoint of improving the hardness of the hard coat layer, the number of radically polymerizable groups contained in one molecule of the radically polymerizable compound is preferably 2 or more, more preferably 3 or more.

[0107] As a free radical polymerizable compound, from the aspect of high reactivity, a compound having a (meth) acryloyl group is preferably used, for example, polyfunctional (meth) acrylate monomers and oligomers having a molecular weight of several hundred to several thousand and having several (meth) acryloyl groups in the molecules of urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, polyfluoroalkyl (meth) acrylate, silicone (meth) acrylate, etc. can be preferably used. In addition, polyfunctional (meth) acrylate polymers having two or more (meth) acryloyl groups in the side chain of the acrylate polymer can also be preferably used. Among them, polyfunctional (meth) acrylate monomers having two or more (meth) acryloyl groups in one molecule can be preferably used. By making the hard coat layer contain a cured product of a polyfunctional (meth) acrylate monomer, the hardness of the hard coat layer can be increased, and then the adhesion can be improved. In addition, polyfunctional (meth) acrylate oligomers or polymers having two or more (meth) acryloyl groups in one molecule can also be preferably used. By making the hard coat layer contain the cured product of the polyfunctional (meth)acrylate oligomer or polymer, the hardness and bending resistance of the hard coat layer can be improved, and the adhesion can be improved.

[0108] In addition, in this specification, (meth)acryloyl group represents an acryloyl group and a methacryloyl group, respectively, and (meth)acrylate represents an acrylate and a methacrylate, respectively.

[0109] About the specific example of multifunctional (meth) acrylate monomer, for example, the material described in Japanese Patent Publication No. 2019-132930 can be cited.Wherein, from the aspect of high reactivity, the hardness of hard coating layer is improved and the aspect of adhesion, it is preferred that there are 3 or more and 6 or less (meth) acryloyl groups in 1 molecule, such as pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate (PETTA), dipentaerythritol pentaacrylate (DPPA), trimethylolpropane tri(meth) acrylate, tripentaerythritol eight (meth) acrylate, four-season pentaerythritol ten (meth) acrylate, etc., particularly preferably selected from pentaerythritol tri(meth) acrylate, dipentaerythritol five (meth) acrylate and dipentaerythritol six acrylate and PO, EO or caprolactone etc. are modified and obtained by at least one of the materials.

[0110] In order to adjust hardness or viscosity, improve adhesion, etc., the resin composition may contain a monofunctional (meth) acrylate monomer as a radical polymerizable compound. Specific examples of monofunctional (meth) acrylate monomers include, for example, those described in Japanese Patent Application Laid-Open No. 2019-132930.

[0111] Cationic polymerizable compounds refer to compounds having cationic polymerizable groups. As the cationic polymerizable groups possessed by the cationic polymerizable compounds, as long as they are functional groups capable of cationic polymerization, there is no particular limitation, and examples thereof include epoxy groups, oxetane groups, vinyl ether groups, etc. It should be noted that when the cationic polymerizable compounds have two or more cationic polymerizable groups, these cationic polymerizable groups may be the same or different.

[0112] From the viewpoint of increasing the hardness of the hard coat layer, the number of cationically polymerizable groups contained in one molecule of the cationically polymerizable compound is preferably 2 or more, more preferably 3 or more.

[0113] In addition, as a cationic polymerizable compound, a compound having at least one of an epoxy group and an oxetane group as a cationic polymerizable group is preferred, and a compound having at least one of two or more epoxy groups and oxetane groups in one molecule is more preferred. From the perspective of the small shrinkage associated with the polymerization reaction, cyclic ether groups such as epoxy groups and oxetane groups are preferred. In addition, compounds having epoxy groups in cyclic ether groups have the following advantages: it is easy to obtain compounds with diverse structures, it will not adversely affect the durability of the obtained hard coating, and the compatibility with free radical polymerizable compounds is also easy to control. In addition, the oxetane group in the cyclic ether group has the following advantages: compared with epoxy groups, the degree of polymerization is high and the toxicity is low. When the obtained hard coating is combined with a compound having an epoxy group, the speed of forming a network structure obtained by the cationic polymerizable compound in the coating film can be accelerated. Even in the area mixed with the free radical polymerizable compound, unreacted monomers will not remain in the film, and an independent network can be formed.

[0114] Examples of the cationically polymerizable compound having an epoxy group include, for example, polyglycidyl ethers of polyols having an alicyclic ring, or alicyclic epoxy resins obtained by epoxidizing a compound containing a cyclohexene ring or a cyclopentene ring using an appropriate oxidizing agent such as hydrogen peroxide or a peracid; aliphatic epoxy resins such as polyglycidyl ethers of aliphatic polyols or alkylene oxide adducts thereof, polyglycidyl esters of aliphatic long-chain polyacids, and homopolymers and copolymers of glycidyl (meth)acrylate; glycidyl ethers produced by the reaction of bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, or their derivatives such as alkylene oxide adducts and caprolactone adducts with epichlorohydrin; and glycidyl ether-type epoxy resins derived from bisphenols such as novolac epoxy resins.

[0115] Specific examples of alicyclic epoxy resins, glycidyl ether epoxy resins, and cationically polymerizable compounds having an oxetane group include those described in JP-A-2018-104682.

[0116] It should be noted that the cured product of the resin composition containing the polymerizable compound contained in the hard coating layer can be analyzed using a Fourier transform infrared spectrophotometer (FTIR), a thermal decomposition gas chromatography device (GC-MS), or the decomposition product of the polymer can be analyzed using a combination of high performance liquid chromatography, gas chromatography-mass spectrometry, NMR, elemental analysis, XPS / ESCA and TOF-SIMS.

[0117] (2) Polymerization initiator

[0118] Resin combination can also contain polymerization initiator as required. As polymerization initiator, free radical polymerization initiator, cationic polymerization initiator, free radical and cationic polymerization initiator etc. can be appropriately selected for use. These polymerization initiators are decomposed by at least one of light irradiation and heating, and free radical or cation is produced to make free radical polymerization and cationic polymerization proceed. It should be noted that, in hard coat, polymerization initiator is sometimes completely decomposed and does not remain.

[0119] Specific examples of radical polymerization initiators and cationic polymerization initiators include those described in JP-A-2018-104682.

[0120] (3) Particles

[0121] The hard coat layer preferably contains inorganic or organic particles, and more preferably contains inorganic fine particles. By making the hard coat layer contain particles, the hardness can be increased.

[0122] As inorganic particles, for example, metal oxide particles such as silicon dioxide (SiO2), aluminum oxide, zirconium oxide, titanium dioxide, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, cerium oxide, metal fluoride particles such as magnesium fluoride and sodium fluoride, metal particles, metal sulfide particles, metal nitride particles, etc. can be cited. Among them, metal oxide particles are preferred, and at least one selected from silicon dioxide particles and aluminum oxide particles is more preferred, and silicon dioxide particles are further preferred. This is because excellent hardness can be obtained.

[0123] In addition, the inorganic particles are preferably reactive inorganic particles having photoreactive functional groups capable of forming covalent bonds on at least a portion of the particle surfaces, in which a crosslinking reaction occurs between the inorganic particles or between the inorganic particles and at least one of the polymerizable compounds. The hardness of the hard coat layer can be further increased by crosslinking between the reactive inorganic particles or between the reactive inorganic particles and at least one of the free radical polymerizable compound and the cationic polymerizable compound.

[0124] The reactive inorganic particles are coated with an organic component on at least a portion of the surface, and the surface has a reactive functional group introduced by the organic component. As the reactive functional group, for example, a polymerizable unsaturated group is suitably used, and a photocurable unsaturated group is more preferably used. As the reactive functional group, for example, ethylenically unsaturated bonds such as (meth)acryloyl, vinyl, and allyl groups, and epoxy groups can be cited.

[0125] The active silica particles are not particularly limited, and conventionally known active silica particles can be used, such as the active silica particles described in Japanese Patent Application Laid-Open No. 2008-165040. Commercially available active silica particles include, for example, MIBK-SD, MIBK-SDMS, MIBK-SDL, and MIBK-SDZL manufactured by Nissan Chemical Industries, Ltd., and V8802 and V8803 manufactured by JGC Catalysts & Chemicals Co., Ltd.

[0126] In addition, the silica particles may be spherical silica particles, but are preferably irregularly shaped silica particles. Spherical silica particles may also be mixed with irregularly shaped silica particles. It should be noted that, in this specification, irregularly shaped silica particles refer to silica particles having a potato-like irregular concave-convex shape on the surface. The irregularly shaped silica particles have a larger surface area than the spherical silica particles, and thus, by containing such irregularly shaped silica particles, the contact area with the above-mentioned resin component etc. is increased, and the hardness of the hard coating layer can be made more excellent.

[0127] It should be noted that whether or not the silica particles are irregularly shaped can be confirmed by observing the cross section of the hard coating layer using an electron microscope.

[0128] From the aspect of improving hardness, the average particle diameter of inorganic particles is preferably 5nm or more, more preferably 10nm or more. If the average particle diameter of inorganic particles is too small, the manufacture of particles is difficult, and particles are likely to be easily agglomerated. In addition, from the aspect of transparency, the average particle diameter of inorganic particles is preferably 200nm or less, more preferably 100nm or less, and further preferably 50nm or less. If the average particle diameter of inorganic particles is too large, it is possible to form large concavo-convex in the hard coat layer, or the haze is likely to increase.

[0129] Here, the average particle size of the inorganic particles can be measured by observing the cross section of the hard coating layer using an electron microscope, and the average particle size of 10 randomly selected particles is taken as the average particle size. It should be noted that the average particle size of the irregular silica particles is the average value of the maximum value (long diameter) and the minimum value (short diameter) of the distance between two points on the periphery of the irregular silica particles appearing in the cross-sectional microscopic observation of the hard coating layer.

[0130] The hardness of the hard coat layer can be controlled by adjusting the size and content of the inorganic particles. For example, the content of the silica particles is preferably 25 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the polymerizable compound.

[0131] (4) Additives

[0132] The hard coat layer used in the present disclosure may contain an ultraviolet absorber. It is possible to suppress the degradation of the above-mentioned resin layer due to ultraviolet rays. Among them, when the above-mentioned resin layer contains polyimide, the color change of the resin layer containing polyimide over time can be suppressed. In addition, in a display device having a display device laminate, it is possible to suppress the degradation of components such as polarizers arranged closer to the display panel side than the display device laminate due to ultraviolet rays.

[0133] Furthermore, the hard coat layer in the present disclosure may contain an antifouling agent, and thus antifouling properties can be imparted to the laminate for a display device.

[0134] Furthermore, the hard coat layer in the present disclosure may further contain different additives as needed. As additives, they may be appropriately selected according to the function imparted to the hard coat layer, and are not particularly limited, and for example, inorganic or organic particles, infrared absorbers, anti-glare agents, antifouling agents, antistatic agents, colorants such as blue pigments or purple pigments, leveling agents, surfactants, lubricants, various sensitizers, flame retardants, adhesion imparting agents, polymerization inhibitors, antioxidants, light stabilizers, surface modifiers, spectral transmittance regulators, etc., may be cited for adjusting the refractive index.

[0135] 4. Method for forming hard coating

[0136] The method for forming the hard coat layer is appropriate depending on the material of the hard coat layer, and examples thereof include a method of applying a hard coat curable resin composition containing the polymerizable compound and the like onto the resin substrate and curing the composition, a vapor deposition method, a sputtering method, and the like.

[0137] As a method for coating the hard coating curable resin composition on the above-mentioned resin substrate, there is no particular limitation as long as it is a method that can be coated with a target thickness, and general coating methods such as gravure coating, reverse gravure coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, screen printing, etc. can be cited. In addition, as a method for forming a coating film of the hard coating resin composition, a transfer method can also be used.

[0138] The coating film of the curable resin composition for hard coating is dried to remove the solvent as needed. As the drying method, for example, reduced pressure drying or heating drying, and a method of combining these drying methods can be cited. For example, drying can be performed by heating at a temperature of 30° C. or more and 120° C. or less for 10 seconds or more and 180 seconds or less.

[0139] The method for curing the coating film of the curable resin composition for a hard coat layer can be appropriately selected according to the polymerizable group of the polymerizable compound, and for example, at least one of light irradiation and heating can be used.

[0140] Light irradiation mainly uses ultraviolet rays, visible rays, electron rays, ionizing rays, etc. In the case of ultraviolet curing, ultraviolet rays emitted by ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arcs, xenon arcs, metal halide lamps, etc. can be used. The irradiation amount of the energy ray source can be, for example, 50 mJ / cm in terms of cumulative exposure at an ultraviolet wavelength of 365 nm. 2 Above 5000mJ / cm 2 Below left and right.

[0141] When heating is performed, the treatment may be performed at a temperature of, for example, 40° C. to 120° C. Alternatively, the reaction may be performed by leaving the mixture at room temperature (25° C.) for 24 hours or more.

[0142] IV. Other layers

[0143] The laminate for a display device of the present disclosure essentially includes the above-mentioned resin layer, resin substrate, and hard coat layer, but may also include other layers as described below.

[0144] 1. Adhesive layer for pasting

[0145] The laminated body for display device of the present disclosure may have an adhesive layer for laminating on the surface of the resin layer opposite to the resin substrate. The laminated body for display device can be laminated to, for example, a display panel via the adhesive layer for laminating.

[0146] As the adhesive used in the adhesive layer for pasting, as long as it is transparent and can bond the display device laminate to the display panel, there is no particular limitation, for example, thermosetting adhesive, ultraviolet curing adhesive, two-liquid curing adhesive, hot melt adhesive, pressure-sensitive adhesive (so-called adhesive) etc. can be cited. Among them, the adhesive layer for pasting preferably contains a pressure-sensitive adhesive, that is, preferably a pressure-sensitive adhesive layer. As the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer, for example, acrylic adhesive, silicone adhesive, rubber adhesive, urethane adhesive etc. can be cited, which can be appropriately selected according to the material of the above-mentioned impact absorbing layer, etc. Among them, acrylic adhesive is preferred. The reason is that it is excellent in transparency, weather resistance, durability, and heat resistance, and the cost is low.

[0147] The thickness of the adhesive layer for pasting is preferably, for example, 10 μm to 100 μm, more preferably 15 μm to 60 μm, and further preferably 25 μm to 50 μm. If the thickness of the adhesive layer for pasting is too thin, it may not be possible to fully bond the display device laminate to the display panel, etc. In addition, when the thickness of the adhesive layer for pasting is too thick, flexibility may be impaired.

[0148] As the pasting adhesive layer, for example, an adhesive film can be used. In addition, for example, an adhesive composition can be applied to a support or a polyimide substrate to form a pasting adhesive layer. The laminate for display device disclosed in the present invention can have a peelable diaphragm layer on the side opposite to the resin layer of the pasting adhesive layer.

[0149] 2. Antifouling layer

[0150] The laminate for display device disclosed in the present invention may have an antifouling layer on the surface of the hard coat layer opposite to the resin substrate. By configuring the antifouling layer, the laminate for display device can be given antifouling properties. As the material of the antifouling layer, general antifouling layer materials can be applied.

[0151] The thickness of the antifouling layer is, for example, preferably 1 nm to 30 nm, more preferably 2 nm to 20 nm, and further preferably 3 nm to 10 nm. If the thickness of the antifouling layer is within the above range, antifouling properties and durability can be improved.

[0152] The method for forming the antifouling layer can be appropriately selected depending on the material of the antifouling layer, and examples thereof include a method of applying a resin composition for an antifouling layer on a hard coat layer and curing the composition, a vacuum deposition method, a sputtering method, and the like.

[0153] 3. Base coating

[0154] The display device laminate in the present disclosure may have a primer layer between the resin substrate and the resin layer. Through the primer layer, the adhesion between the resin substrate and the resin layer can be improved. In addition, for the same reason, a primer layer may be provided between the resin substrate and the hard coat layer.

[0155] As the material of the primer layer, there is no particular limitation as long as it is a material that can improve the adhesion between the resin substrate and the resin layer or the adhesion between the resin substrate and the hard coat layer, and for example, resins can be cited. As resins, for example, (meth) acrylic resins, urethane resins, (meth) acrylic acid urethane copolymers, vinyl chloride-vinyl acetate copolymers, polyesters, butyral resins, chlorinated polypropylene, chlorinated polyethylene, epoxy resins, silicone resins, etc. can be cited. These resins can be used alone or in combination of two or more.

[0156] The thickness of the primer layer may be any thickness that can improve the adhesion between the resin substrate and the resin layer or between the resin substrate and the hard coating layer, and may be, for example, 0.1 μm to 10 μm, preferably 0.2 μm to 5 μm.

[0157] As the formation method of the primer layer, for example, a method of applying a primer composition on a resin substrate can be enumerated. As the coating method, for example, general coating methods such as gravure coating, reverse gravure coating, gravure offset coating, spin coating, roller coating, reverse roll coating, scraper coating, dip coating, screen printing can be enumerated. In addition, as the formation method of the primer layer, a transfer method can also be used.

[0158] 4. Anti-reflection layer

[0159] The laminate for display device of the present disclosure may include an antireflection layer on the surface of the hard coat layer opposite to the resin substrate. By providing the antireflection layer, reflection of external light can be suppressed and visibility can be improved.

[0160] The material constituting the antireflection layer is preferably a material having a predetermined light transmittance and a predetermined flexibility. Specifically, materials that can be used for general antireflection layers are mentioned, and therefore description thereof is omitted here.

[0161] V. Others

[0162] The display device laminate of the present disclosure also has the following features.

[0163] 1. Total thickness of resin substrate and resin layer

[0164] In the laminate for display device disclosed herein, the total thickness of the resin substrate and the resin layer is 50 μm or more, preferably 70 μm or more. By setting the total thickness within the above range, the curvature of the hard coating layer at the above sliding bending portion can be prevented from being locally increased, thereby suppressing the generation of cracks in the hard coating layer.

[0165] On the other hand, the total thickness is 130 μm or less, preferably 120 μm or less. By making the total thickness within the above range, the rebound force relative to the bending direction can be suppressed, the height difference of the support plate can be followed, and the floating of the adhesive layer can be suppressed. In addition, in the sliding bending portion, the elongation of the hard coating layer arranged at the outermost periphery can be suppressed, and the generation of cracks can be reliably suppressed.

[0166] 2. Resistance to sliding bending

[0167] The display device laminate of the present disclosure preferably has the above-mentioned sliding bend resistance. Specifically, the sliding bend resistance of the display device laminate can be evaluated by performing the sliding bend test described below. The sliding bend test is performed as follows.

[0168] [Sliding bending test]

[0169] Figure 6 Schematic diagram for explaining the sliding bending test. First, a 20 mm × 100 mm size laminate for a display device is prepared. Figure 6 As shown in (a), the prepared display device laminate 10 is attached to the test support plate 31 via the test adhesive layer 32 to obtain a test piece 30. Here, a schematic top view of the test support plate 31 is shown in FIG. Figure 7 As shown in (a). Figure 7 As shown in FIG. 1 , the test support plate is a support plate in which a through pattern is formed by etching on a SUS304 plate having a thickness of 150 μm. Figure 7 The values ​​in represent length (mm). Figure 7 (b) is Figure 7 A partial enlarged view of one block in (a). Figure 7 (c) is Figure 7 (b) is a partial enlarged view of FIG. 1. Specifically, the test adhesive layer 32 is Adhesive 8146-1 manufactured by 3M Company (the thickness of the adhesive layer after the separator is peeled off is 25 μm).

[0170] Then, if Figure 6 As shown in (b), the test piece 30 was bent with the test support plate 31 as the inner side, and one end side and the other end side in the length direction were opposite to each other, and in this state, it was set in a sliding tester (DMLHB-FU, YUASA Co., Ltd.). Then, with the above-mentioned one end side fixed, the other end side was slid with a sliding length (stroke length) of 35 mm, a sliding speed of 30 rpm, and a sliding diameter d of 8.0 mm (radius 4.0 mm), and it was repeatedly reciprocated.

[0171] The laminated body in the present disclosure preferably does not cause lifting of the adhesive layer and cracking of the hard coating layer when the above-mentioned sliding bending test is repeated 200,000 times.

[0172] Furthermore, it is more preferable that neither the adhesive layer is lifted nor the hard coating layer is cracked when the sliding bending test is repeated 200,000 times with the sliding diameter d changed to 7 mm (radius 3.5 mm).

[0173] It is particularly preferred that no lifting of the adhesive layer or cracking of the hard coating layer occurs when the sliding bending test is repeated 200,000 times with the sliding diameter d changed to 6 mm (radius 3.0 mm).

[0174] 3. Thickness

[0175] The thickness of the display device laminate of the present disclosure is preferably 55 μm to 150 μm, more preferably 70 μm to 140 μm, and further preferably 85 μm to 130 μm. If the thickness of the display device laminate is within the above range, the flexibility can be improved, and further, the laminate can be easily stored in a display device such as a slidable display.

[0176] 4. Total light transmittance and haze

[0177] The total light transmittance of the display device laminate in the present disclosure is, for example, preferably 80% or more, more preferably 85% or more, and further preferably 88% or more. With such a high total light transmittance, a display device laminate having good transparency can be obtained.

[0178] Here, the total light transmittance of the laminate for a display device can be measured in accordance with JIS K7361-1, for example, by using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

[0179] The haze of the laminated body for display devices in the present disclosure is, for example, preferably 2.0% or less, more preferably 1.5% or less, and further preferably 1.0% or less. With such a low haze, a laminated body for display devices having good transparency can be obtained.

[0180] Here, the haze of the laminate for a display device can be measured in accordance with JIS K-7136, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

[0181] VI. Purpose

[0182] The display device laminate of the present disclosure is a member disposed on the viewer side of a display panel in a display device.

[0183] When the laminated body for display devices in the present disclosure is arranged on the surface of a display device, it is preferably arranged so that the surface on the resin layer side faces the display panel side and the surface on the hard coat layer side faces the outside.

[0184] The method of disposing the display device laminate in the present disclosure on the surface of the display device is not particularly limited, and examples thereof include a method using an adhesive layer, etc. The adhesive layer includes an adhesive layer for pasting the display device laminate.

[0185] The display device laminate of the present disclosure can be used for display devices used in electronic devices such as smartphones, tablet terminals, wearable terminals, personal computers, televisions, digital signage, public information displays (PIDs), and car displays. Among them, the display device laminate of the present disclosure can be used for flexible displays, preferably for slidable displays and rollable displays, and more preferably for slidable displays.

[0186] B. Display device

[0187] A display device in the present disclosure includes a display panel and the display device laminated body disposed on the viewer side of the display panel.

[0188] Figure 8 is a schematic cross-sectional view showing an example of a display device in the present disclosure. Figure 8 As shown, the display device 40 includes a display panel 41 and a display device laminate 10 disposed on the viewer side of the display panel 41. In the display device 40, the display device laminate 10 and the display panel 41 can be bonded together, for example, via an additional adhesive layer 42. In the display device 40, the surface of the hard coat layer 2 of the display device laminate 10 constitutes a surface 40A of the display device 40.

[0189] It should be noted that, although not shown here, the display panel 41 is bonded to a support plate having a linear through pattern with a length direction perpendicular to the screen expansion direction in the area becoming the curved portion by an adhesive layer as described in the item "A. Laminated body for display device".

[0190] Fig. 9 is a schematic cross-sectional view showing another example of the display device in the present disclosure. Fig. 9 As shown, the display device 40 sequentially includes a housing 43 storing a battery, etc., a protective film 44, a display panel 41, a touch panel member 45, and a display device laminate 10. An additional adhesive layer 42 is disposed between the display panel 41 and the touch panel member 45, and between the touch panel member 45 and the display device laminate 10, and these members are fixed to each other by the additional adhesive layer 42. In this example as well, the display panel 41 is bonded to the above-mentioned support plate (not shown) by the adhesive layer.

[0191] The display device laminate in the present disclosure is the same as the above-mentioned "A. display device laminate", and thus the description thereof is omitted here.

[0192] Examples of the display panel in the present disclosure include display panels used in display devices such as liquid crystal display devices, organic EL display devices, and LED display devices.

[0193] The display device in the present disclosure may include a touch panel member between the display panel and the display device laminate.

[0194] The display device in the present disclosure is preferably a flexible display. Examples of flexible displays include slidable displays, rollable displays, and foldable displays. Among them, the display device in the present disclosure is preferably a display that is bent in a manner such that the display device laminate becomes the outside and is bent while sliding. That is, the display device in the present disclosure is more preferably a slidable display and a rollable display. Since the display device in the present disclosure has the above-mentioned display device laminate, it has excellent scratch resistance and sliding bending resistance, and is suitable as a flexible display, especially a slidable display and a rollable display.

[0195] C. Display device with support plate

[0196] The display device with a support plate in the present disclosure includes a display device and a support plate disposed on a surface of the display device on the display panel side. The display device is a flexible display, and the support plate has a through pattern penetrating in a thickness direction.

[0197] Fig.10 is a schematic cross-sectional view showing an example of a display device with a support plate in the present disclosure. Fig.10 As shown, the display device 70 with a support plate has the above-mentioned display device 40 and a support plate S arranged on the surface 40B on the display panel 41 side of the display device 40. "The surface 40B on the display panel 41 side of the display device 40" refers to the surface of the display device 40 located on the display panel 41 side when the display device stack 10 is used as a reference. The display device 40 is a flexible display. The support plate S has a through pattern (through hole) that penetrates in the thickness direction. The support plate S is easy to bend together with the display device by having a through pattern. On the other hand, the support plate has a through pattern, so that there is a high height difference with a curvature locally, so it is easy to produce the above-mentioned undesirable situation. On the other hand, the display device with a support plate in the present disclosure has the above-mentioned display device stack, so based on the above-mentioned reasons, it is possible to suppress the undesirable situation of the bending portion (especially the sliding bending portion).

[0198] The display device in the present disclosure is a flexible display. Examples of flexible displays include slidable displays, rollable displays, foldable displays, etc. Among them, a display that is configured on a support plate S while sliding and bending is preferred. That is, the display device in the present disclosure is more preferably a slidable display and a rollable display.

[0199] Other features of the display device are the same as those in the above-mentioned "B. Display device", so their description is omitted here.

[0200] The support plate is preferably made of metal (for example, SUS). The through pattern on the support plate is preferably a linear through pattern, wherein the through pattern is preferably a linear through pattern extending in a direction perpendicular to the sliding direction (screen expansion direction). Fig.10 The support plate preferably has a plurality of through patterns. For example, Figure 7 As shown in the test support plate, the support plate preferably has a plurality of blocks consisting of a plurality of densely packed through patterns (through holes) along the sliding direction. The width ( Fig.10The reference numeral W) is, for example, 0.1 mm or more, or 0.2 mm or more. On the other hand, it is, for example, 1 mm or less, or 0.5 mm or less. The thickness of the support plate is, for example, 100 μm or more, or 150 μm or more. On the other hand, it is, for example, 300 μm or less.

[0201] like Fig.10 As shown, it is preferable that an adhesive layer 71 is disposed between the support plate S and the display panel 41. As the adhesive layer disposed between the support plate and the display panel, the same adhesive layer as the above-mentioned adhesive layer for pasting can be cited.

[0202] It should be noted that the present disclosure is not limited to the above-mentioned embodiments. The above-mentioned embodiments are illustrative, and technical solutions having substantially the same structure and having the same effects as the technical ideas described in the claims of the present disclosure are all included in the technical scope of the present disclosure.

[0203] Example

[0204] Hereinafter, examples and comparative examples are shown to further illustrate the present disclosure.

[0205] (Example 1, Examples 3 to 6, Examples 8 to 11, Comparative Examples 1 to 5)

[0206] First, as a resin substrate, PET having a thickness shown in Table 2 was prepared. A hard coat layer was formed on one surface of the resin substrate using the following hard coat layer composition.

[0207] The hard coat layer composition and the method for forming the hard coat layer used in the examples and comparative examples are as follows.

[0208] <Preparation of Hard Coat Composition>

[0209] First, each component was mixed so as to have the composition shown below to obtain a composition for a hard coat layer.

[0210] (Composition for hard coating)

[0211] Urethane acrylate (product name "UX5000", manufactured by Nippon Kayaku Co., Ltd.): 30 parts by mass

[0212] A mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (product name "M403", manufactured by Toagosei Co., Ltd.): 35 parts by mass

[0213] · Multifunctional acrylate polymer (product name "ACRIT8 KX-012C", manufactured by Taisei Fine Chemical Co., Ltd.): 35 parts by mass (solid content 100% conversion value)

[0214] Fluorine-based leveling agent (product name "F568", manufactured by DIC Corporation): 0.2 parts by mass (based on 100% solid content)

[0215] Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 3 parts by mass

[0216] Methyl isobutyl ketone (MIBK): 150 parts by mass

[0217] In addition, the "solid content 100% conversion value" means a value when the solid content in the solvent-diluted product is assumed to be 100%.

[0218] <Formation of Hard Coat Layer>

[0219] The hard coating composition was applied to one side of the resin substrate using a rod coater to form a coating film. The formed coating film was then heated at 70°C for 1 minute to evaporate the solvent in the coating film. Next, an ultraviolet irradiation device (FusionUV Systems Japan, light source H bulb) was used to irradiate the substrate under the condition that the oxygen concentration was below 200 ppm, with the accumulated light amount reaching 300 mJ / cm 2 The coating was fully cured by irradiating ultraviolet rays in a manner of 100 μm. Thus, a hard coating layer with a film thickness of 5 μm was formed.

[0220] Next, a resin layer was formed on the surface of the resin substrate opposite to the hard coat layer side using the resin layer composition, thereby obtaining a laminate for a display device.

[0221] The resin layer composition and the method for forming the resin layer used in Examples and Comparative Examples are as follows.

[0222] <Preparation of Resin Layer Composition>

[0223] The respective components were blended so as to have the compositions shown in Table 1, thereby obtaining compositions 1 to 6 for a resin layer.

[0224] Urethane acrylate 1: Urethane acrylate (product name "UV3310B", manufactured by Nippon Synthetic Chemical Co., Ltd., bifunctional)

[0225] Urethane acrylate 2: Urethane acrylate (product name "UV2000B", manufactured by Nippon Synthetic Chemical Co., Ltd., bifunctional)

[0226] Acrylate compound 1: a mixture of tripentaerythritol acrylate, monopentaerythritol acrylate, dipentaerythritol acrylate, and polypentaerythritol acrylate (product name: "Viscoat#802", manufactured by Osaka Organic Chemical Industry Co., Ltd.)

[0227] Acrylate compound 2: ethoxylated pentaerythritol tetraacrylate (product name "ATM-35E", manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0228] Acrylate compound 3: phenoxyethyl acrylate (product name "Viscoat #192", manufactured by Osaka Organic Chemical Industry Co., Ltd.)

[0229] Polymerization initiator: 1-hydroxycyclohexyl phenyl ketone (product name "Omnirad 184", manufactured by IGM Resins BV)

[0230] Antifouling agent: Product name "BYK-302", manufactured by BYK-Chemie

[0231] Solvent: Methyl isobutyl ketone (MIBK)

[0232] <Formation of Resin Layer>

[0233] The resin layer composition shown in Table 2 was applied to the surface of the resin substrate opposite to the hard coating layer using a bar coater to form a coating film. The formed coating film was then heated at 70°C for 2 minutes to evaporate the solvent in the coating film. Next, an ultraviolet irradiation device (Fusion UV Systems Japan, light source H bulb) was used to irradiate the substrate at an oxygen concentration of 200 ppm or less, with a cumulative light intensity of 300 mJ / cm 2 The coating was irradiated with ultraviolet light in a manner to fully cure the coating. Thus, a resin layer having a film thickness shown in Table 2 was formed. The total thickness of the resin substrate and the resin layer is shown in Table 2.

[0234] [Table 1]

[0235]

[0236] (Example 2, Example 7 and Example 12)

[0237] Instead of using a resin layer composition to form a resin layer, a resin film formed of 100 μm thermoplastic urethane (product name "DUS270-C ER", manufactured by Sheedom Co., Ltd.) was cut into film thicknesses shown in Table 2 (Example 2: 35 μm, Example 7: 20 μm, Example 12: 5 μm) and attached to a resin substrate to form a resin layer. Except for this, the same operation as in Example 1 was carried out to obtain a laminate for a display device.

[0238] [Indenter penetration]

[0239] The cross-sectional indenter penetration amounts of the resin substrate and the resin layer were measured for the laminates for display devices obtained in Examples 1 to 12 and Comparative Examples 1 to 5 in the same manner as described in “A. Laminated body for display device I. Resin layer”.

[0240] [Table 2]

[0241]

[0242] [evaluate]

[0243] (Steel wool test (abrasion resistance test)

[0244] First, a protective film having an adhesive layer on one side of a PET substrate (PET substrate thickness: 100 μm to 125 μm, adhesive layer thickness: 10 μm to 25 μm) was attached to the resin layer side of a 4 cm × 10 cm laminate in a manner that does not cause curling, and then the end of the laminate was fixed to the test bench of the Gakushin type friction fastness tester AB-301 manufactured by TESTER SANGYO using a transparent tape. Next, #0000 steel wool (BONSTAR #0000 manufactured by Japan Steel Wool Co., Ltd.) was used to fix the steel wool to a 2 cm × 2 cm fixture, and the temperature was 23 ± 5 ° C, the humidity was 40 ± 10% RH, the load was 500 g, the reciprocating speed was 40 rpm, the reciprocating distance was 40 mm, and the steel wool installation area was 4 cm 2 The hard coating layer side of the display device laminate was rubbed back and forth 1000 times under the conditions of . Then, the presence or absence of damage was confirmed by transmission and reflection. The results are shown in Table 3.

[0245] (Sliding bending test)

[0246] The obtained laminate was subjected to a sliding bending test to evaluate its bending resistance. First, a laminate for a display device having a size of 20 mm × 100 mm was prepared. Figure 6 As shown in (a), the prepared display device laminate 10 is attached to a test support plate 31 via a test adhesive layer 32 so as not to cause curling, thereby obtaining a test piece 30. The test support plate 31 is used Figure 7 The SUS304 plate with a through pattern having a thickness of 150 μm is shown. The test adhesive layer 32 is Adhesive 8146-1 manufactured by 3M Company (the thickness of the adhesive layer after the separator is peeled off is 25 μm).

[0247] Then, if Figure 6As shown in (b), the support plate 31 is bent in such a way that it becomes the inner side, so that one end side in the length direction is opposite to the other end side, and in this state, it is set in a sliding tester (product name "DMLHB-FU" manufactured by YUASA SYSTEM). Next, in a state where the above-mentioned one end side is fixed, the other end side is slid with a sliding length (stroke length) of 35mm, a sliding speed of 30rpm, and a sliding diameter d7.0mm (radius 3.5mm), and it is repeated 200,000 times (condition 1). In addition, except that the sliding diameter d is changed to 6mm (radius 3.0mm), under the same conditions, 200,000 reciprocations are repeated in the above-mentioned sliding bending test (condition 2). It should be noted that the sliding diameter d is the interval between one end side and the other end side in the length direction of the stacked body for the display device. The results of the sliding bending test are evaluated according to the following criteria.

[0248] Crack evaluation

[0249] A: Under Condition 2, cracks did not occur in the hard coating layer (HC layer) of the laminate.

[0250] B: Cracks occurred in the hard coating layer (HC layer) of the laminate under condition 2, but no cracks occurred under condition 1.

[0251] C: Under Condition 2 and Condition 1, cracks occurred in the hard coating layer (HC layer) of the laminate.

[0252] Floating evaluation

[0253] A: Even under Condition 2, the adhesive layer did not lift off from the support plate.

[0254] B: Under condition 2, the adhesive layer was lifted off from the support plate, but under condition 1, the adhesive layer was not lifted off.

[0255] C: Under Condition 2 and Condition 1, the adhesive layer was lifted off from the support plate.

[0256] [Table 3]

[0257]

[0258] As shown in Table 3, it was confirmed that the scratch resistance of Comparative Example 1 was low due to the thick thickness of the resin layer. In addition, in Comparative Example 2, it was confirmed that the indenter penetration amount of the resin layer was too large and it was too soft, so the scratch resistance was low. In Comparative Example 3, the indenter penetration amount of the resin layer was too small and hard, so the adhesive layer floated. In Comparative Example 4, the combined thickness of the resin substrate and the resin layer was too thin, so sufficient height difference absorption performance could not be obtained, and cracks occurred in the hard coating. In Comparative Example 5, the combined thickness of the resin substrate and the resin layer was too thick, so the adhesive layer floated. Examples 1 to 12 have excellent scratch resistance, and the results of the sliding bending test are good. It should be noted that the thickness of the resin layer of Example 12 is thinner than that of the other examples, and the adhesive layer floated slightly under Condition 1, but it is to a degree that there is no problem in actual use (B ※ ).

[0259] That is, the present disclosure can provide the following inventions. [1]

[0261] A laminate for a display device, comprising: a resin substrate; a hard coating layer arranged on one surface of the resin substrate; and a resin layer arranged on the surface of the resin substrate opposite to the hard coating layer, wherein the cross-sectional indentation meter indentation amount of the resin layer is greater than 200 nm and less than 3000 nm, the cross-sectional indentation meter indentation amount of the resin substrate is smaller than the cross-sectional indentation meter indentation amount of the resin layer, the thickness of the resin layer is greater than 5 μm and less than 45 μm, and the total thickness of the resin substrate and the resin layer is greater than 50 μm and less than 130 μm. [2]

[0263] The laminate for a display device according to [1], wherein the cross-sectional indentation depth of the resin substrate is less than 200 nm. [3]

[0265] The laminate for a display device according to [1] or [2], wherein the resin substrate includes at least one of polyethylene terephthalate, triacetyl cellulose, and polyimide. [4]

[0267] The display device laminate according to any one of [1] to [3], wherein the hard coat layer has a thickness of 5 μm or more and 20 μm or less. [5]

[0269] A stacked body for a display device as described in any one of [1] to [4], wherein, in the following sliding bending test performed on a test piece prepared by bonding the stacked body for a display device to a test support plate by means of a test adhesive layer, when the sliding diameter is set to 7.0 mm and the test adhesive layer is not peeled off and the hard coating layer does not crack when the sliding diameter is set to 7.0 mm and the test is repeated 200,000 times.

[0270] [Sliding bending test]

[0271] A 20 mm × 100 mm laminate for a display device was prepared, and the laminate was attached to a 150 μm thick SUS304 test support plate having a through pattern by means of a test adhesive layer to obtain a test piece. The test piece was bent with the test support plate on the inside so that one end side in the length direction was opposite to the other end side. In this state, the laminate was set in a sliding tester (DMLHB-FU manufactured by YUASA Co., Ltd.). Next, while fixing the one end side, the other end side was slid with a sliding length, i.e., a stroke length of 35 mm and a sliding speed of 30 rpm, and the test piece was repeatedly reciprocated. [6]

[0273] The laminate for a display device according to any one of [1] to [5], wherein a bonding adhesive layer is provided on a surface of the resin layer opposite to the resin substrate. [7]

[0275] A display device includes a display panel and the display device laminate according to any one of [1] to [6] disposed on the viewer side of the display panel, wherein the display device laminate is disposed such that the hard coating layer side is the viewer side. [8]

[0277] A display device with a support plate, comprising the display device described in [7] and a support plate disposed on a surface of the display device on the display panel side, wherein the display device is a flexible display and the support plate has a through pattern penetrating in a thickness direction. [9]

[0279] The display device with a support plate as described in [8] is a display that bends while sliding when arranged on the support plate.

[10]

[0281] The display device with a support plate as described in [9], wherein the through pattern is a linear through pattern with a length direction perpendicular to the sliding direction.

[11]

[0283] The display device with a support plate according to any one of [8] to

[10] , wherein an adhesive layer is provided between the display device and the support plate.

[0284] Description of Reference Numerals

[0285] 1…Resin base material

[0286] 2…Hard coating

[0287] 3…Resin layer

[0288] 10...Laminate for display device

[0289] 40…Display device

[0290] 41…Display Panel

[0291] 42…Light-transmitting adhesive layer

[0292] 43…Housing

[0293] 44…Protective film

[0294] 45…Touch panel components

Claims

1. A laminate for a display device, comprising: a resin substrate; a hard coating layer disposed on one surface of the resin substrate; and a resin layer disposed on a surface of the resin substrate opposite to the hard coating layer, The cross-sectional indentation depth of the resin layer is greater than or equal to 200 nm and less than or equal to 3000 nm. The cross-sectional indentation meter penetration amount of the resin substrate is smaller than the cross-sectional indentation meter penetration amount of the resin layer, The thickness of the resin layer is 5 μm or more and 45 μm or less, The total thickness of the resin substrate and the resin layer is 50 μm or more and 130 μm or less.

2. The display device laminate according to claim 1, wherein: The cross-section indentation instrument indentation amount of the resin substrate is less than 200 nm.

3. The display device laminate according to claim 1, wherein: The resin substrate includes at least one of polyethylene terephthalate, triacetyl cellulose and polyimide.

4. The display device laminate according to claim 1, wherein: The hard coating layer has a thickness of 5 μm or more and 20 μm or less.

5. The display device laminate according to claim 1, wherein: In the following sliding bending test conducted on a test piece prepared by bonding the display device laminate to a test support plate via a test adhesive layer, when the sliding diameter was set to 7.0 mm and the test adhesive layer was repeatedly reciprocated 200,000 times, no peeling of the test adhesive layer occurred, and no cracks occurred in the hard coating layer, [Sliding bending test] A 20 mm × 100 mm laminate for a display device is prepared, and the laminate is attached to a 150 μm thick SUS304 test support plate having a through pattern by means of a test adhesive layer to obtain a test piece. The test piece is bent with the test support plate on the inside so that one end side in the length direction is opposite to the other end side. In this state, the test piece is set on a sliding tester. Next, while fixing the one end side, the other end side is slid with a sliding length, i.e., a stroke length of 35 mm and a sliding speed of 30 rpm, and the test piece is repeatedly reciprocated. The sliding tester is DMLHB-FU manufactured by YUASA Co., Ltd.

6. The display device laminate according to claim 1, wherein: The resin layer has an adhesive layer for pasting on a surface opposite to the resin substrate. 7 . A display device comprising a display panel and the display device laminate according to claim 1 , which is arranged on the viewer side of the display panel, wherein the display device laminate is arranged such that the hard coat layer side is the viewer side.

8. A display device with a support plate, comprising the display device according to claim 7 and a support plate disposed on a surface of the display device on the display panel side, wherein the display device is a flexible display and the support plate has a through pattern penetrating in a thickness direction.

9. The display device with a support plate according to claim 8, wherein: The display device is a display that is bent while sliding when arranged on the support plate.

10. The display device with a support plate according to claim 9, wherein: The penetration pattern is a linear penetration pattern whose longitudinal direction is a direction perpendicular to the sliding direction.

11. The display device with a support plate according to claim 8, wherein: An adhesive layer is provided between the display device and the support plate.

Images