Stacked body for display device and display device

Abstract

The present invention provides a laminate for a display device, which is a laminate for a display device having a substrate layer and a fluorine-containing functional layer. After a rubber test in which the functional layer side of the laminate for the display device is subjected to a 9.8N load and reciprocated rubbing for 2500 cycles using a rubber with a diameter of 6mm, the absolute value of the charge on the functional layer side of the laminate for the display device is 10.0nC or less.

Description

Technical Field

[0001] This invention relates to laminates for display devices and display devices using the same. Background Technology

[0002] A laminate with a functional layer is disposed on the surface of the display device. This functional layer has various properties such as hard coating, scratch resistance, anti-reflection, anti-glare, antistatic, and anti-fouling.

[0003] In recent years, touch functionality has been incorporated not only into smartphones and tablets, but also into display devices such as laptops. In touch-enabled display devices, since operation is performed by direct contact with the surface using fingers, durability and slip resistance are required.

[0004] Furthermore, portable display devices such as smartphones and tablets are sometimes stored in places like clothing pockets or bags, and their surfaces are often subjected to friction from the fabric of the clothing or bag, or from other items inside the pocket or bag. Therefore, portable display devices require additional abrasion resistance.

[0005] Recently, flexible displays such as foldable displays, rollable displays, and bendable displays have attracted attention, and the development of laminates disposed on the surface of flexible displays is actively underway. For example, research is being conducted on using resin substrates instead of glass substrates. For instance, Patent Document 1 proposes a display device window film that has a plastic substrate with high hardness and excellent optical properties, and a hard coating disposed on at least one side of the plastic substrate.

[0006] Flexible displays, for example, are used or stored in a bent state, making the surfaces of the bent parts susceptible to friction. Therefore, in flexible displays, excellent wear resistance is further required for the bent parts.

[0007] To improve wear resistance, it is known to reduce the coefficient of friction, for example. Specifically, techniques for imparting low friction by coating with fluorine-based surface treatment agents or adding fluorine-based additives are known. For example, Patent Document 2 discloses a surface treatment agent containing a polymer composition of fluorinated oxidized alkenyl groups, which can provide a coating with excellent water and oil resistance, scratch resistance, low dynamic friction, and wear resistance.

[0008] However, due to friction on the surface of the functional layer in the above-mentioned laminate, the components contained in the functional layer may be rubbed away or the functional layer may be worn thin, which may sometimes reduce the performance of the functional layer. Further improvement in wear resistance is expected.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2016-125063

[0012] Patent Document 2: Japanese Patent No. 6140348 Summary of the Invention

[0013] The problem that the invention aims to solve

[0014] The present invention was made in view of the above-mentioned actual situation, and its main purpose is to provide a laminate for a display device with excellent wear resistance and a display device.

[0015] Methods for solving problems

[0016] In order to solve the above-mentioned problems, the inventors of this invention focused on the rubber test as an abrasion test and conducted in-depth research on the abrasion resistance of laminates used in display devices. Surprisingly, they discovered a new correlation between abrasion resistance and the absolute value of charge. This invention is based on this technical concept.

[0017] One embodiment of the present invention provides a laminate for a display device, which is a laminate for a display device having a substrate layer and a fluorine-containing functional layer, wherein, after a rubber test in which the functional layer side surface of the laminate for the display device is subjected to a 9.8N load and reciprocated rubbing for 2500 cycles using a rubber with a diameter of 6mm, the absolute value of the charge on the functional layer side surface of the laminate for the display device is 10.0nC or less.

[0018] In the laminate for display devices of the present invention, the ratio of the initial average value of the frictional force against the rubber relative to the functional layer side surface of the initial laminate for display devices to the maximum value of the frictional force against the rubber after the rubber test is preferably 1.7 or less.

[0019] Furthermore, in the laminate for the display device of the present invention, the ratio of the number of fluorine atoms on the surface of the functional layer side to the total number of atoms of all elements, as determined by X-ray photoelectron spectroscopy, is preferably 0.4 or higher.

[0020] Furthermore, in the laminate for the display device of the present invention, the aforementioned functional layer preferably contains an antistatic agent. In this case, the antistatic agent is preferably a conductive polymer.

[0021] Furthermore, the laminate for display devices in this invention can have an impact-absorbing layer on the side of the substrate layer opposite to the functional layer, or between the substrate layer and the functional layer.

[0022] Furthermore, the laminate for display devices in this invention may have an adhesive layer for attachment on the side of the substrate layer opposite to the functional layer.

[0023] Another embodiment of the present invention provides a display device comprising: a display panel and the aforementioned display device laminate disposed on the observer side of the display panel.

[0024] The effects of the invention

[0025] In this invention, the effect of providing a laminate for a display device and a display device with excellent wear resistance is achieved. Attached Figure Description

[0026] Figure 1 This is a schematic cross-sectional view illustrating the laminate for the display device in this invention.

[0027] Figure 2 This is a schematic diagram illustrating the method for measuring the frictional force of rubber.

[0028] Figure 3 This is a schematic diagram illustrating the dynamic bending test.

[0029] Figure 4 This is a schematic cross-sectional view illustrating the laminate for the display device in this invention.

[0030] Figure 5 This is a schematic cross-sectional view illustrating the laminate for the display device in this invention.

[0031] Figure 6 This is a schematic cross-sectional view illustrating the laminate for the display device in this invention.

[0032] Figure 7 This is a schematic cross-sectional view illustrating the display device of the present invention. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the present invention can be implemented in many different ways and is not to be construed as limited to the embodiments illustrated below. Furthermore, to make the description clearer, the drawings sometimes schematically represent the width, thickness, shape, etc., of various parts compared to the actual situation; however, these are always examples and are not intended to limit the interpretation of the present invention. In addition, in this specification and the accompanying drawings, the same reference numerals are used for elements identical to those described in the previously mentioned drawings, and detailed descriptions are appropriately omitted.

[0034] In this specification, when describing the arrangement of other components above a component, the use of only "above" or "below" includes, unless otherwise specified, both the case where the other component is arranged directly above or below the component in contact with it, and the case where the other component is arranged above or below the component, further separated by another component. Similarly, in this specification, when describing the arrangement of another component on the surface of a component, the use of only "surface side" or "surface" includes, unless otherwise specified, both the case where the other component is arranged directly above or below the component in contact with it, and the case where the other component is arranged above or below the component, further separated by another component.

[0035] The inventors of this invention focused on the rubber test as an abrasion test and conducted in-depth research on the abrasion resistance of laminates for display devices, and obtained the following insights.

[0036] The inventors of this invention conducted a rubber test on the laminated body used in display devices, measuring the frictional force before and after the test, as well as the amount of charge after the test. The results showed that when the absolute value of the charge after the test was small, the change in frictional force before and after the test tended to be smaller. That is, a correlation was found between abrasion resistance and the absolute value of the charge after the test. Furthermore, the relationship between abrasion resistance and the absolute value of the charge after the test was investigated in detail, and it was found that to impart excellent abrasion resistance, it is important that the absolute value of the charge after the test is below a specified value.

[0037] The following is a detailed description of the display device laminate and the display device in this invention.

[0038] A. Laminated substrate for display devices

[0039] The display device laminate of the present invention is a display device laminate having a substrate layer and a fluorine-containing functional layer. After a rubber test in which a 9.8N load is applied to the functional layer side surface of the display device laminate 2500 times using a 6mm diameter rubber, the absolute value of the charge on the functional layer side surface of the display device laminate is 10.0nC or less.

[0040] Figure 1 This is a schematic cross-sectional view illustrating an example of a laminated body for a display device according to the present invention. Figure 1 As shown, the laminate 1 for the display device has a substrate layer 2 and a functional layer 3. Furthermore, after a specified rubber test, the absolute value of the charge on the surface of the functional layer 3 side of the laminate 1 for the display device is below a specified value.

[0041] As described above, the present invention is based on a novel discovery that there is a correlation between abrasion resistance and the absolute value of charge after a rubber test in laminates for display devices. In the present invention, excellent abrasion resistance can be obtained by ensuring that the absolute value of charge on the functional layer side of the laminate for display devices after a rubber test is below a predetermined value.

[0042] The reasoning is not yet clear, but it is speculated as follows: If a rubber test is performed on the surface of the laminate used in the display device, the surface of the laminate will become charged due to friction. Generally, the surface of a fluorine-containing layer tends to become negatively charged. Therefore, the functional layer containing fluorine is prone to becoming negatively charged, and through friction with a rubber, the functional layer side of the laminate becomes negatively charged. Due to this effect, the contact surface between the rubber and the functional layer side of the laminate becomes positively charged. If the electrostatic force increases after the rubber test (i.e., the absolute value of the charge after the rubber test is large), the attraction increases, and it is assumed that the fluorine contained in the functional layer will detach and easily adhere to the rubber. If the fluorine contained in the functional layer detaches, the wear resistance effect provided by the fluorine decreases. On the other hand, if the electrostatic force is small even after the rubber test (i.e., the absolute value of the charge after the rubber test is small), the attraction is small, and it is assumed that the fluorine contained in the functional layer is difficult to detach. In this case, the wear resistance effect provided by the fluorine can be maintained. Therefore, it is believed that in this invention, by making the absolute value of the charge on the functional layer side of the laminate for display devices after the rubber test below a predetermined value, it is possible to suppress the charging of the functional layer side of the laminate for display devices caused by the rubber test, and to suppress the fluorine detachment caused by the rubber test as described above.

[0043] As a result, it is speculated that excellent wear resistance can be obtained.

[0044] Furthermore, since the friction of an eraser is similar to that of a stylus, the eraser test can evaluate the abrasion resistance to relatively soft materials such as styluses, fingers, clothing, or bag fabrics. In this invention, since the absolute value of the surface charge on the functional layer side of the laminate for display devices after the eraser test is below a specified value, excellent abrasion resistance can be obtained for relatively soft materials such as styluses, fingers, clothing, or bag fabrics.

[0045] The following describes the various configurations of the display device laminate in this invention.

[0046] 1. Characteristics of laminates used in display devices

[0047] In this invention, after a rubber test was conducted in which a 9.8N load was applied to the functional layer side surface of the laminate for display devices using a 6mm diameter rubber for reciprocating friction 2500 times, the absolute value of the charge on the functional layer side surface of the laminate for display devices was 10.0nC or less, preferably 8nC or less, and more preferably 6nC or less. By ensuring that the absolute value of the charge is within the above range, excellent wear resistance can be obtained. Furthermore, the smaller the absolute value of the charge, the more preferred it is; for example, it can be 0nC.

[0048] Here, the rubber test can be performed as follows: Using a 6mm diameter rubber, insert it into a fixture with a 6mm diameter hole, ensuring the front end of the rubber protrudes 4mm. Mount this fixture with the rubber into a vibration-type friction testing machine, and rub the rubber against the functional layer side of the laminate for the display device 2500 times under conditions of a load of 9.8N, a moving speed of 80mm / s, and a moving distance of 40mm. For example, a 6mm diameter rubber can be used. The rubber. Additionally, as a vibration-type friction testing machine, the AB-301 vibration-type friction fastness testing machine manufactured by TESTER SANGYO can be used, for example.

[0049] In addition, the amount of charge can be measured by the following method. First, using a glass plate as a test stage, the ion generator is brought into contact with the glass plate for 1 minute to remove charge. Next, a test piece is made by cutting the display device into a laminate of 20mm × 80mm (including a 6mm × 40mm rubber test section), and the ion generator is brought into contact with both sides of the test piece for 30 to 60 seconds to remove charge.

[0050] Next, the end of the test piece was fixed to a glass plate with transparent tape, and the rubber test was performed. Then, the test piece after the rubber test was placed in a Faraday cage, the temperature was set to 23±5℃ and the humidity was set to 40±10%RH, and the charge was measured.

[0051] At this point, using insulated and non-magnetic tweezers, pinch the untested portion of the rubber (the end of the sample) and lift the test piece after the rubber test. After lifting the test piece, measure the charge without contacting other fixed surfaces. The charge measurement should be performed within 3 minutes after the rubber test. Furthermore, the charge measurement area should cover the entire surface of the sample.

[0052] As a Faraday cage, a Faraday cage such as the "KQ-1400" manufactured by Kasuga Electric Co., Ltd. can be used. Additionally, as an ion generator, a fan-type ion generator such as the "KD-750B" manufactured by Kasuga Electric Co., Ltd. can be used. Furthermore, as tweezers, ESD (static discharge) tweezers such as the "P-643-S" manufactured by Kenis Co., Ltd. can be used.

[0053] Methods for adjusting the absolute value of the charge on the surface of the functional layer of the laminate for display devices after the rubber test include, for example: adjusting the surface hardness of the functional layer; adjusting the thickness of the functional layer; adjusting the fluorine concentration on the surface of the functional layer of the laminate for display devices; adjusting the content of the antistatic agent; adjusting the position of the layer containing the antistatic agent; adjusting the drying temperature during the formation of the functional layer; etc.

[0054] For example, if the surface hardness of the functional layer increases, the absolute value of the aforementioned charge tends to decrease. Conversely, if the thickness of the functional layer decreases, the surface hardness of the functional layer tends to decrease and the absolute value of the aforementioned charge tends to increase; conversely, if the thickness of the functional layer increases, the surface hardness of the functional layer tends to increase and the absolute value of the aforementioned charge tends to decrease. Furthermore, if the fluorine concentration on the functional layer side of the laminate for the display device increases, the sliding properties tend to improve and the absolute value of the aforementioned charge tends to decrease; conversely, if the fluorine concentration on the functional layer side of the laminate for the display device decreases, the sliding properties tend to decrease and the absolute value of the aforementioned charge tends to increase.

[0055] Furthermore, for example, if the content of antistatic agent increases, there is a tendency for the absolute value of the charge to decrease. However, if the content of antistatic agent is too high, there is a tendency for the surface hardness of the functional layer to decrease and the absolute value of the charge to increase. On the other hand, if the content of antistatic agent decreases, there is a tendency for the surface hardness of the functional layer to increase and the absolute value of the charge to decrease.

[0056] Furthermore, for example, if the distance between the surface of the rubber test and the layer containing the antistatic agent becomes closer, there is a tendency for the absolute value of the charge to decrease; on the other hand, if the distance between the surface of the rubber test and the layer containing the antistatic agent becomes farther, there is a tendency for the absolute value of the charge to increase.

[0057] In this invention, the distance between the surface where the rubber test is performed and the layer containing the antistatic agent is preferably less than 10 μm, particularly preferably less than 6 μm, and most preferably less than 4 μm.

[0058] Here, "the distance between the surface where the rubber test is performed and the layer containing the antistatic agent" refers to the following distance.

[0059] That is, "the surface on which the rubber test is performed" refers to the outermost surface of the functional layer in the laminate for the display device. Furthermore, "the layer containing the antistatic agent" refers to the layer that initially contains the antistatic agent when viewed from the outermost surface towards the substrate layer. In other words, if the outermost layer contains an antistatic agent, then the outermost layer is a layer containing an antistatic agent; if the outermost layer does not contain an antistatic layer, but the next layer contains an antistatic agent, then the next layer becomes a "layer containing an antistatic agent".

[0060] "Distance between the surface where the rubber test is performed and the layer containing the antistatic agent" refers to the distance from the outermost surface to the surface of the outermost side of the "layer containing the antistatic agent".

[0061] Furthermore, for example, if the drying temperature during the formation of the functional layer is lower, there is a tendency for the absolute value of the aforementioned charge to decrease. On the other hand, if the drying temperature during the formation of the functional layer is higher, there is a tendency for the antistatic agent to be difficult to transfer to the surface of the functional layer, and for the absolute value of the aforementioned charge to increase.

[0062] Furthermore, in this invention, when a steel wool test was conducted on the functional layer side of the laminate for display devices, applying a specified load to the surface and rubbing it 2500 times with #0000 steel wool, the maximum load on which no scratches were observed on the functional layer side of the laminate for display devices was preferably 4.9 N or more, more preferably 9.8 N or more, and even more preferably 14.7 N or more. By setting the maximum load to the above range, the hardness of the functional layer side of the laminate for display devices can be increased, thereby improving scratch resistance.

[0063] Here, the steel wool test can be performed as follows: Using #0000 steel wool, fix the steel wool to a 2cm × 2cm clamp, and rub it back and forth 2500 times on the functional layer side of the display device laminate at a reciprocating speed of 40 rpm and a reciprocating distance of 40 mm. The #0000 steel wool can be BONSTAR#0000 manufactured by NIHON STEEL WOOL. Additionally, the testing machine can be, for example, the AB-301 vibration-type rubbing fastness tester manufactured by TESTER SANGYO. It should be noted that the steel wool test is performed under the following conditions: for example, after attaching a protective film with an adhesive layer on one side of a PET substrate to the substrate layer side of a 4cm × 10cm display device laminate, place the laminate in the testing machine with the functional layer side facing up, and secure the ends of the display device laminate with transparent tape.

[0064] It should be noted that the steel wool test can evaluate the abrasion resistance of relatively hard items, such as those in clothing pockets or bags.

[0065] Furthermore, in this invention, the pencil hardness of the functional layer side surface of the laminate for display devices is preferably H or higher, more preferably 2H or higher, and even more preferably 3H or higher. By setting the pencil hardness to the above range, the hardness of the functional layer side surface of the laminate for display devices can be increased, thereby improving scratch resistance.

[0066] Here, pencil hardness is determined by the pencil hardness test specified in JIS K5600-5-4 (1999). Specifically, it can be performed as follows: using a test pencil specified in JIS-S-6006, the functional layer side of the laminate for display devices is subjected to the pencil hardness test specified in JIS K5600-5-4 (1999), and the highest pencil hardness without damage is evaluated. The test conditions can be an angle of 45°, a load of 1000g, a speed of 0.5 mm / s to 1 mm / s, and a temperature of 23±2°C. For the pencil hardness testing machine, a pencil scratch coating hardness testing machine manufactured by Toyo Seiki Co., Ltd., for example, can be used.

[0067] Furthermore, in this invention, the average value of the frictional force of the functional layer side of the laminate for the display device against the rubber is preferably, for example, 0.98N or more and 9.80N or less, more preferably 1.96N or more and 8.80N or less, and even more preferably 2.45N or more and 7.80N or less. If the initial average value of the frictional force against the rubber is within the above range, the wear resistance can be improved.

[0068] Furthermore, in this invention, after conducting a rubber test in which a 9.8N load is applied to the functional layer side of the laminate for the display device and rubbed repeatedly for 2500 cycles, the maximum value of the frictional force between the functional layer side of the laminate for the display device and the rubber is preferably, for example, 0.98N or more and 9.80N or less, more preferably 1.96N or more and 8.80N or less, and even more preferably 2.45N or more and 7.80N or less. By ensuring that the frictional force between the rubber and the rubber after the above rubber test is within the above range, excellent wear resistance can be obtained, and excellent antistatic properties can be maintained.

[0069] Furthermore, for the functional layer side of the laminate for the display device, the ratio of the maximum value of the frictional force against the rubber after the rubber test to the initial average value of the frictional force against the rubber is preferably 1.7 or less, more preferably 1.5 or less, and even more preferably 1.3 or less. By making the ratio of the frictional force against the rubber within the above range, wear resistance can be improved. In addition, the smaller the ratio of the frictional force against the rubber, the more preferred it is; for example, it can be 1.00.

[0070] Regarding the ratio of frictional force to the rubber mentioned above, when the average value of the frictional force of the functional layer side of the display device laminate before the rubber test is set as A, and the maximum value of the frictional force of the functional layer side of the display device laminate after the rubber test is set as B, it can be calculated by the following formula.

[0071] The ratio of frictional forces = B / A

[0072] Regarding the friction force of the rubber, a 6mm diameter rubber can be used. The rubber is inserted into a fixture with a 6mm diameter hole, with the front end protruding 4mm. This fixture with the rubber is then mounted onto a friction testing machine. The friction is measured using the functional layer side of a laminated material with a load of 1.96N and a moving speed of 840mm / min. For example, a 6mm diameter rubber can be used. The rubber. Additionally, as a friction testing machine, the TRIBOGEAR TYPE18 manufactured by Shin-To Science Co., Ltd. can be used. Specifically, such as... Figure 2 As shown, firstly, the aforementioned rubber test is performed on a portion of the functional layer side surface 30 of the laminate 1 for the display device, forming a rectangular rubber test implementation part 32. Next, using an eraser, as indicated by the arrow, the functional layer side surface 30 of the laminate 1 for the display device is rubbed in the order of the untested portion 31, the rubber test implementation part 32, and the untested portion 31, and the friction force is measured. At this time, as indicated by the arrow, the eraser is moved perpendicularly to the length direction of the rectangular rubber test implementation part 32. The average value of the friction force on the eraser from the untested portion can be taken as the initial average value of the friction force on the eraser, and the maximum value of the friction force on the eraser from the rubber test implementation part can be taken as the maximum value of the friction force on the eraser after the rubber test. Furthermore, regarding the initial average value of the friction force on the eraser, as... Figure 2 As shown, when the point where the frictional force of the rubber reaches its maximum value in the rubber test implementation section 32 is set to 0mm, the average value of the frictional force in the rubber test non-implementation section 31 is within a range of 4.2mm to 9.8mm based on the aforementioned point (0mm).

[0073] Furthermore, in this invention, the ratio of the number of fluorine atoms on the functional layer side of the laminate for display devices, as determined by X-ray photoelectron spectroscopy, to the total number of atoms of all elements is preferably, for example, 7 at% to 60 at% or less, more preferably 20 at% to 50 at% or less, and even more preferably 25 at% to 45 at% or less. If the initial ratio of the number of fluorine atoms is within the above range, wear resistance can be improved.

[0074] Furthermore, in this invention, after a rubber test in which a 9.8N load is applied to the functional layer side of the laminate for a display device and rubbed repeatedly for 2500 cycles using a 6mm diameter rubber, the ratio of the number of fluorine atoms on the functional layer side of the laminate for a display device to the total number of atoms of all elements, as determined by X-ray photoelectron spectroscopy, is preferably 7 at% to 60 at% and less, more preferably 20 at% to 50 at% and less, and even more preferably 25 at% to 45 at% and less. If the ratio of the number of fluorine atoms after the rubber test is within the above range, the fluorine contained in the functional layer can be suppressed from detaching due to the rubber test, thereby improving wear resistance.

[0075] Furthermore, relative to the ratio of the number of fluorine atoms on the functional layer side of the initial display device laminate as determined by X-ray photoelectron spectroscopy to the total number of atoms of all elements, the ratio of the number of fluorine atoms on the functional layer side of the display device laminate after the rubber test to the total number of atoms of all elements is preferably 0.4 or more, more preferably 0.6 or more, and even more preferably 0.7 or more. By setting the ratio of the number of fluorine atoms to the above range, wear resistance can be improved. In addition, the higher the ratio of the number of fluorine atoms, the more preferred it is; for example, it can be 1.0.

[0076] The ratio of the number of fluorine atoms mentioned above is calculated using the following formula, where C is the ratio of the number of fluorine atoms on the functional layer side of the initial display device laminate before the rubber test to the total number of atoms of all elements, and D is the ratio of the number of fluorine atoms on the functional layer side of the display device laminate after the rubber test to the total number of atoms of all elements.

[0077] The ratio of the number of fluorine atoms = D / C

[0078] Furthermore, in this invention, the ratio of the number of fluorine atoms on the surface of the rubber to the total number of atoms of all elements, as determined by X-ray photoelectron spectroscopy, is preferably below the detection limit, for example.

[0079] Furthermore, in this invention, after a rubber test in which a 9.8 N load is applied to the functional layer side of the laminate for display devices using a 6 mm diameter rubber for 2500 cycles of reciprocating friction, the ratio of the number of fluorine atoms on the contact surface of the rubber with the functional layer side of the laminate for display devices to the total number of atoms of all elements, as determined by X-ray photoelectron spectroscopy, is preferably 15 at% or less, more preferably 10 at% or less, and even more preferably 5 at% or less. If the ratio of the number of fluorine atoms on the contact surface of the rubber after the above rubber test is within the above range, it is possible to suppress the fluorine contained in the functional layer from detaching from and adhering to the rubber due to the rubber test, thereby improving wear resistance.

[0080] Here, the ratio of fluorine atoms to the total number of atoms of all elements is the ratio of the number of fluorine atoms present on the sample surface to the total number of atoms of all elements, as determined by X-ray photoelectron spectroscopy (XPS). Specifically, it refers to the ratio (at%) of fluorine atoms when the total number of carbon, oxygen, fluorine, nitrogen, silicon, calcium, and chlorine atoms is set to 100 at%.

[0081] The ratio of fluorine atoms to the total number of atoms of all elements can be determined by analyzing the composition of the sample surface using X-ray photoelectron spectroscopy (XPS). Specifically, it can be determined by the following steps: First, X-ray photoelectron spectrometers are used to irradiate the sample surface with X-rays along the depth direction under the following conditions, and the X-ray photoelectron spectrum is measured. For example, the AXIS-NOVA manufactured by Kratos can be used as the X-ray photoelectron spectrometer. When determining the ratio of fluorine atoms to the total number of atoms of all elements, C, O, F, N, Si, Ca, and Cl can be used as the analyte elements. The background determined by the Shirley method is subtracted from the obtained spectrum, and the ratio of fluorine atoms (at%) is calculated from the peak area using the relative sensitivity coefficient method, with the total number of carbon, oxygen, fluorine, nitrogen, silicon, calcium, and chlorine atoms set at 100 at%.

[0082] <Measurement Conditions>

[0083] Incident X-rays: Monochromated Al-Kα rays (Hv = 1486.6 eV)

[0084] • X-ray irradiation area (measurement area):

[0085] X-ray output power: 150W (15kV, 6.7mA)

[0086] • Photoelectron measurement angle: 90°±15° (set the sample normal to 0°)

[0087] • Charge neutralization conditions: Electron neutralization gun (+6V, 0.05mA), low-acceleration Ar + Ion irradiation

[0088] • Measured peaks: C1s, O1s, F1s, N1s, Si2p, Ca2p, Cl2p

[0089] Furthermore, when measuring the ratio of fluorine atoms on the functional layer side of the initial display device laminate to the total number of atoms of all elements, and the ratio of fluorine atoms on the functional layer side of the display device laminate after the rubber test to the total number of atoms of all elements, for example, as described above, it is possible to form a structure as follows: Figure 2 The rubber test execution unit 32 shown uses the ratio of the number of fluorine atoms in the rubber test non-execution unit 31 to the total number of atoms of all elements as the initial ratio of the number of fluorine atoms to the total number of atoms of all elements, and uses the ratio of the number of fluorine atoms in the rubber test execution unit 32 to the total number of atoms of all elements as the ratio of the number of fluorine atoms to the total number of atoms of all elements after the rubber test.

[0090] The total light transmittance of the laminate for display devices in this invention is preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more. This high total light transmittance enables the fabrication of a laminate for display devices with excellent transparency.

[0091] Here, the total light transmittance of the laminate used in the display device can be measured according to JIS K7361-1, for example, by using the HM150 haze meter manufactured by the Murakami Color Technology Research Institute.

[0092] The haze of the laminate for display devices in this invention is preferably 5% or less, more preferably 2% or less, and even more preferably 1% or less. By making the haze so low, it is possible to produce a laminate for display devices with good transparency.

[0093] Here, the haze of the laminate used in the display device can be measured according to JIS K-7136, for example, by using the HM150 haze meter manufactured by Murakami Color Technology Research Institute.

[0094] The laminate for display devices in this invention preferably has bending resistance. Specifically, it is preferable that the laminate for display devices does not crack or break when subjected to the dynamic bending test described below.

[0095] The dynamic bending test is conducted as follows. First, a laminated body for the display device measuring 20mm × 100mm is prepared. Then, in the dynamic bending test, as... Figure 3 As shown in (a), the short side portion 1C and the short side portion 1D facing the short side portion 1C are respectively fixed by the parallelly arranged fixing parts 51. Furthermore, as... Figure 3 As shown in (a), the fixing part 51 can slide in the horizontal direction. Next, as... Figure 3 As shown in (b), the fixing parts 51 are moved closer together, thereby causing the display device to fold and deform using the laminate 1, and thus, as shown in (b), Figure 3 As shown in (c), the fixing part 51 is moved to a position where the distance d between the two opposing short sides 1C and 1D fixed by the fixing part 51 of the display device laminate 1 reaches a predetermined value. Then, the fixing part 51 is moved in the opposite direction to eliminate deformation of the display device laminate 1. By moving the fixing part 51 as shown... Figure 3 The movement shown in (a) to (c) allows the display device laminate 1 to be folded 180°. Furthermore, by performing a dynamic bending test ensuring that the bent portion 1E of the display device laminate 1 does not protrude from the lower end of the fixing portion 51, and by controlling the interval when the fixing portions 51 are closest, the interval d between the two opposing short sides 1C and 1D of the display device laminate 1 can be set to a predetermined value. For example, when the interval d between the short sides 1C and 1D is 30 mm, the outer diameter of the bent portion 1E is considered to be 30 mm.

[0096] In the laminate for display devices, it is preferable that no cracks or fractures occur after repeated 200,000 dynamic bending tests in which the opposing short sides 1C and 1D of the laminate 1 for display devices are folded 180° with a spacing d of 30 mm. More preferably, it is preferable that no cracks or fractures occur after repeated 500,000 tests. Among these, it is preferable that no cracks or fractures occur after repeated 200,000 dynamic bending tests in which the opposing short sides 1C and 1D of the laminate for display devices are folded 180° with a spacing d of 20 mm. Particularly preferable that no cracks or fractures occur after repeated 200,000 dynamic bending tests in which the opposing short sides 1C and 1D of the laminate for display devices are folded 180° with a spacing d of 10 mm.

[0097] In dynamic bending tests, the laminate for display devices can be folded with the functional layers on the outside or with the functional layers on the inside. However, in either case, it is preferable that the laminate for display devices does not crack or break.

[0098] 2. Functional layer

[0099] The functional layer in this invention is a fluorine-containing layer disposed on one side of the substrate layer. By containing fluorine in the functional layer, wear resistance and stain resistance can be imparted to the laminate used in the display device.

[0100] As a functional layer, there are no particular limitations as long as it contains fluorine. Functional layers can contain, for example, fluorinated compounds and resins, or fluorinated resins.

[0101] When the functional layer contains fluorinated compounds and resins, substances known as fluorinated antifouling agents, fluorinated leveling agents, and fluorinated surfactants can be used as fluorinated compounds. Examples of fluorinated compounds include organofluorine compounds, and more specifically, perfluorinated compounds. Examples of perfluorinated compounds include those having perfluoropolyether groups, perfluoroalkylene groups, and perfluoroalkyl groups. Perfluoroalkylene and perfluoroalkyl groups can be straight-chain or branched. A single fluorinated compound can be used, or two or more can be used in combination.

[0102] Furthermore, fluorine compounds are preferably combined with resin components. By combining fluorine compounds with resin components, the leaching of fluorine compounds can be inhibited, allowing the abrasion resistance and stain resistance to be maintained for a long time. In addition, abrasion resistance and stain resistance can be easily maintained after rubber testing.

[0103] Since it is preferable to combine with the resin component, a fluorine compound having reactive functional groups is preferred. That is, the functional layer preferably contains a cured resin composition comprising a fluorine compound having reactive functional groups and a polymerizable compound described later. Examples of reactive functional groups include, for example, olefinic unsaturated groups such as (meth)acryloyl, vinyl, and allyl, epoxy groups, and oxetane.

[0104] The fluorine compound may have one or more reactive functional groups, preferably two or more. By using a fluorine compound having two or more reactive functional groups, scratch resistance and abrasion resistance can be improved.

[0105] In addition, fluorine compounds can also contain silicon. That is, the functional layer can contain both fluorine and silicon. Examples of fluorine compounds containing silicon include those with intramolecular siloxane bonds. By using fluorine compounds with siloxane bonds, slip properties and scratch resistance can be improved. Furthermore, slippage when touched with fingers, styluses, etc., is improved, thus enhancing the tactile experience.

[0106] Fluorine compounds are preferably, for example, fluorine compounds having reactive functional groups, or fluorine compounds containing reactive functional groups and silicon.

[0107] Examples of fluorinated compounds with reactive functional groups include fluorinated monomers having olefinic unsaturated bonds, fluorinated polymers or oligomers with fluorinated alkylene groups in the main chain, and fluorinated polymers or oligomers with fluorinated alkylene groups or fluorinated alkyl groups in the main chain and side chains. For example, Japanese Patent Application Publication No. 2017-19247 can be consulted regarding fluorinated compounds with reactive functional groups.

[0108] Examples of fluorine compounds containing reactive functional groups and silicon include, for instance, organosilicon copolymers containing organosilicon obtained by reacting an organosilicon molecule having reactive functional groups with the aforementioned fluorine compound having reactive functional groups.

[0109] Furthermore, as fluorinated compounds containing reactive functional groups and silicon, fluorinated compounds having reactive functional groups and perfluoropolyether groups are preferred, especially fluorinated compounds containing silane units having reactive functional groups and silane units having perfluoropolyether groups. For example, International Publication No. 2012 / 157682 can be consulted regarding such fluorinated compounds.

[0110] In the functional layer, the fluorinated compound can be present uniformly or biased towards the side of the functional layer opposite to the substrate layer. Preferably, the fluorinated compound is biased towards the side of the functional layer opposite to the substrate layer. This allows for sufficient abrasion resistance and stain resistance with a relatively small amount added, and suppresses the reduction of the surface hardness of the functional layer.

[0111] As a method to concentrate the fluorinated compound on the side of the functional layer opposite to the substrate layer, for example, when the functional layer is a single layer, the following methods can be used: During the formation of the functional layer, a resin composition for the functional layer is coated onto the substrate layer, dried, and before curing, the coating is heated to reduce the viscosity of the resin component contained in the coating, thereby increasing its fluidity, thus concentrating the fluorinated compound on the side of the functional layer opposite to the substrate layer; or, using a fluorinated compound with low surface tension, the fluorinated compound floats on the surface of the coating without heat during drying, and then the coating is cured, thus concentrating the fluorinated compound on the side of the functional layer opposite to the substrate layer; etc. Furthermore, for example, when the functional layer is multilayered, by containing a fluorinated compound in the layer of the multilayer functional layer located on the side opposite to the substrate layer, the fluorinated compound can be concentrated on the side of the functional layer opposite to the substrate layer.

[0112] The amount of fluorine compound is not particularly limited as long as it is sufficient to obtain a functional layer that satisfies the absolute value of the aforementioned charge. For example, it is preferably 0.01 parts by mass to 15 parts by mass relative to 100 parts by mass of the resin component. If the fluorine compound content is too low, it may not be able to impart sufficient wear resistance and stain resistance to the functional layer. On the other hand, if the fluorine compound content is too high, the surface hardness and wear resistance of the functional layer may decrease.

[0113] Furthermore, when the functional layer contains fluorinated compounds and resins, examples of resins include cured polymeric compounds. Cured polymeric compounds can be obtained by using a polymerization initiator and known methods to polymerize the polymeric compound as needed.

[0114] The polymerizable compound has at least one polymerizable functional group within its molecule. At least one of, for example, free radical polymerizable compounds and cationic polymerizable compounds can be used as polymerizable compounds.

[0115] A free radical polymerizable compound is a compound that possesses free radical polymerizable groups. The free radical polymerizable groups in a free radical polymerizable compound can be any functional group capable of undergoing a free radical polymerization reaction; there are no particular limitations. Examples include groups containing carbon-carbon unsaturated double bonds, such as vinyl groups and (meth)acryloyl groups. It should be noted that when a free radical polymerizable compound has two or more free radical polymerizable groups, these groups can be the same or different.

[0116] From the perspective of increasing the surface hardness and improving the scratch resistance of the functional layer, the number of free radical polymerizable groups in one molecule of the free radical polymerizable compound is preferably two or more, and more preferably three or more.

[0117] As a free radical polymerizable compound, compounds with high reactivity are preferred, particularly those containing (meth)acryloyl groups. Polyfunctional (meth)acrylate monomers and oligomers with molecular weights ranging from several hundred to several thousand, such as those called urethane (meth)acrylates, polyester (meth)acrylates, epoxy (meth)acrylates, melamine (meth)acrylates, polyfluoroalkyl (meth)acrylates, and silicone (meth)acrylates, are also preferred. Furthermore, polyfunctional (meth)acrylate polymers with two or more (meth)acryloyl groups on the side chains of the acrylate polymer are also preferred. Specifically, polyfunctional (meth)acrylate monomers with two or more (meth)acryloyl groups per molecule are preferred. By curing a functional layer containing polyfunctional (meth)acrylate monomers, the surface hardness of the functional layer can be improved, and scratch resistance can be enhanced. Furthermore, adhesion can also be improved. Additionally, polyfunctional (meth)acrylate oligomers or polymers with two or more (meth)acryloyl groups per molecule are also preferred. By incorporating cured polyfunctional (meth)acrylate oligomers or polymers into the functional layer, the surface hardness of the functional layer can be increased, thereby improving scratch resistance. This, in turn, also enhances flexural strength and adhesion.

[0118] It should be noted that in this specification, (meth)acryloyl group refers to acryloyl group and methacryloyl group respectively, and (meth)acrylate refers to acrylate and methacrylate respectively.

[0119] Specific examples of polyfunctional (meth)acrylate monomers include, for instance, the substances described in Japanese Patent Application Publication No. 2019-132930. Among these, substances having 3 or more but 6 or fewer (meth)acryloyl groups per molecule are preferred, considering their high reactivity, improved surface hardness of the functional layer, and enhanced scratch resistance. Examples of such polyfunctional (meth)acrylate monomers include, for instance, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate (PETTA), dipentaerythritol pentaacrylate (DPPA), trimethylolpropane tri(meth)acrylate, tripentaerythritol octa(meth)acrylate, and pentaerythritol deca(meth)acrylate. Particularly preferred are at least one selected from pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexaacrylate.

[0120] Furthermore, when using free radical polymerizable compounds, scratch resistance can sometimes be reduced due to flexible groups within the molecular structure. Therefore, to suppress the decrease in scratch resistance caused by flexible components (soft segments), it is preferable to use free radical polymerizable compounds that do not incorporate flexible groups into their molecular structure. Specifically, it is preferable to use free radical polymerizable compounds that are not modified with EO or PO. By using such free radical polymerizable compounds, the number of crosslinking points can be increased, thereby improving scratch resistance.

[0121] To adjust hardness or viscosity, improve adhesion, etc., the functional layer may contain monofunctional (meth)acrylate monomers as free radical polymerizable compounds. Specific examples of monofunctional (meth)acrylate monomers include, for instance, the substance described in Japanese Patent Application Publication No. 2019-132930.

[0122] Cationic polymerizable compounds are compounds that possess cationic polymerizable groups. The cationic polymerizable groups in a cationic polymerizable compound can be any functional group capable of undergoing a cationic polymerization reaction; there are no particular limitations. Examples include epoxy groups, oxetyl groups, and vinyl ether groups. It should be noted that when a cationic polymerizable compound has two or more cationic polymerizable groups, these cationic polymerizable groups can be the same or different.

[0123] From the perspective of increasing the surface hardness and improving the scratch resistance of the functional layer, the number of cationic polymerizable groups in one molecule of the cationic polymerizable compound is preferably two or more, and more preferably three or more.

[0124] Furthermore, as cationic polymerizable compounds, compounds having at least one of epoxy groups and oxetyl groups as cationic polymerizable groups are preferred, and compounds having at least two of epoxy groups and oxetyl groups in one molecule are more preferred. From the perspective of minimizing shrinkage associated with the polymerization reaction, cyclic ether groups such as epoxy groups and oxetyl groups are preferred. In addition, compounds having epoxy groups in the cyclic ether group have the following advantages: they readily produce compounds with diverse structures, do not adversely affect the durability of the obtained functional layer, and their compatibility with free radical polymerizable compounds is easily controlled. Furthermore, oxetyl groups in the cyclic ether group have the following advantages: they have a higher degree of polymerization and lower toxicity compared to epoxy groups; when the obtained functional layer is combined with compounds having epoxy groups, the formation rate of the network structure obtained from the cationic polymerizable compound in the coating film can be accelerated; even in areas mixed with free radical polymerizable compounds, no unreacted monomers remain in the film, and an independent network structure can be formed.

[0125] Examples of cationic polymerizable compounds with epoxy groups include, for instance, polyglycidyl ethers of polyols having alicyclic rings, or alicyclic epoxy resins obtained by epoxidizing compounds containing cyclohexene or cyclopentene rings using suitable oxidants such as hydrogen peroxide or peroxyacids; alicyclic epoxy resins such as polyglycidyl ethers of aliphatic polyols or their epoxy alkyl adducts, polyglycidyl esters of aliphatic long-chain polyacids, and homopolymers and copolymers of (meth)acrylate glycidyl esters; glycidyl ethers manufactured by reacting bisphenols such as bisphenol A, bisphenol F, and hydrogenated bisphenol A, or their epoxy alkyl adducts, caprolactone adducts, and other derivatives with epichlorohydrin; and glycidyl ether-type epoxy resins derived from bisphenols, such as phenolic varnish epoxy resins.

[0126] Specific examples of alicyclic epoxy resins, glycidyl ether type epoxy resins, and cationic polymerizable compounds having oxocyclic butyl groups can be cited, for example, as the substances described in Japanese Patent Application Publication No. 2018-104682.

[0127] The functional layer may contain polymerization initiators as needed. Suitable polymerization initiators include free radical polymerization initiators, cationic polymerization initiators, and a combination of free radical and cationic polymerization initiators. These initiators are decomposed by at least one of light irradiation and heating, generating free radicals or cations to initiate free radical and cationic polymerization. It should be noted that sometimes, in the functional layer, the polymerization initiator is completely decomposed without any residue.

[0128] Furthermore, when the functional layer contains a fluorinated resin, examples of fluorinated polymeric compounds include cured products of such resins. Cured products of fluorinated polymeric compounds can be obtained by using a polymerization initiator and a known method to polymerize the fluorinated polymeric compound as needed.

[0129] Fluorine-containing polymeric compounds have at least one polymerizable functional group within their molecules. At least one of, for example, free radical polymeric compounds and cationic polymeric compounds can be used as fluorine-containing polymeric compounds. Furthermore, any one of, for example, fluorine-containing monomers, oligomers, and polymers can be used as fluorine-containing polymeric compounds.

[0130] Furthermore, when the functional layer contains a fluorinated resin, a fluorine-free polymeric compound can be used in addition to a fluorinated polymeric compound. That is, the functional layer can contain a cured product of a resin composition comprising both a fluorinated polymeric compound and a fluorine-free polymeric compound. The fluorine-free polymeric compound can be the same as the polymeric compound used when the functional layer contains a fluorinated compound and a resin.

[0131] Furthermore, the functional layer preferably contains an antistatic agent. This imparts antistatic properties to the laminate for display devices. Additionally, by adjusting the content of the antistatic agent, the absolute value of the surface charge on the functional layer side of the laminate for display devices after a rubber test can be adjusted to a specified range.

[0132] Examples of antistatic agents include ion-conducting antistatic agents and electron-conducting antistatic agents. Antistatic agents can be used alone or in combination of two or more.

[0133] As ion-conducting antistatic agents, either low-molecular-weight or high-molecular-weight antistatic agents can be used. High-molecular-weight antistatic agents are, for example, formed by increasing the molecular weight of ion-conducting antistatic agents, or by introducing functional groups from ion-conducting antistatic agents to impart conductivity to the polymer. Examples of ion-conducting antistatic agents include: cationic antistatic agents such as quaternary ammonium salts and pyridinium salts; anionic antistatic agents such as alkali metal salts of sulfonic acids, phosphoric acids, and carboxylic acids such as lithium salts, sodium salts, and potassium salts; amphoteric antistatic agents such as amino acid-based and amino acid sulfate-based agents; nonionic antistatic agents such as amino alcohol-based, glycerol-based, and polyethylene glycol-based agents; and ionic liquids. Among these, quaternary ammonium salts and lithium salts are preferred due to their excellent compatibility with resins.

[0134] Examples of electronically conductive antistatic agents include conductive polymers such as polyacetylene and polythiophene; conductive particles such as metal particles, metal oxide particles, and carbon nanotubes; and conductive fibers. Additionally, antistatic agents incorporating dopants into conductive polymers such as polyacetylene and polythiophene, or antistatic agents containing conductive particles within the aforementioned conductive polymers, can also be used. Among these, conductive polymers are preferred from the perspective of maintaining antistatic properties.

[0135] Specifically, examples of the aforementioned conductive polymers include: polyacetylene, polyaniline, polythiophene, polypyrrole, polyphenylene sulfide, poly(1,6-heptadiyne), polybiphenylene (poly-p-phenylene), poly-p-phenylene sulfide, polyphenylacetylene, poly(2,5-thiophene), or derivatives thereof. Polythiophene-based conductive polymers, such as 3,4-ethylenedioxythiophene (PEDOT), are preferred. By using these conductive polymers as antistatic agents, antistatic properties can be maintained for a long time.

[0136] Examples of metals constituting the aforementioned metal particles include individual metals such as Au, Ag, Cu, Al, Fe, Ni, Pd, and Pt, or alloys of these metals.

[0137] The metal oxide constituting the aforementioned metal oxide particles is not particularly limited, and examples include tin oxide, antimony oxide, antimony-doped tin oxide (ATO), tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), fluorine-doped tin oxide (FTO), and zinc oxide (ZnO). Among these, antimony-doped tin oxide (ATO) is preferred from the perspective of exhibiting excellent antistatic properties. Furthermore, in the case of ATO, chain-like ATO composed of multiple ATO particles is preferred.

[0138] Among the aforementioned antistatic agents, polymeric antistatic agents and conductive polymers are preferred, with conductive polymers being more preferred. Even small amounts of polymeric antistatic agents and conductive polymers can impart antistatic properties while maintaining surface hardness and optical properties.

[0139] In addition, if the functional layer contains an antistatic agent and the functional layer is multi-layered as described below, it is sufficient that at least one of the multi-layered functional layers contains an antistatic agent.

[0140] In this case, any layer in the multilayer functional layers may contain the antistatic agent. Preferably, the layer located near the side opposite to the substrate layer contains the antistatic agent, and particularly preferably, the layer located on the side opposite to the substrate layer, i.e., the outermost layer of the multilayer functional layers, contains the antistatic agent. This is because the closer the surface where the rubber test is performed is to the layer containing the antistatic layer, the easier it is to adjust the absolute value of the charge on the functional layer side of the display device laminate after the rubber test to a specified range.

[0141] The amount of antistatic agent is not particularly limited as long as it is sufficient to obtain a functional layer with the absolute value of the aforementioned charge. It can be appropriately selected based on the type of antistatic agent. Relative to 100 parts by mass of the resin component, the content of the antistatic agent is preferably 0.1 parts by mass to 100 parts by mass, more preferably 0.2 parts by mass to 50 parts by mass, and even more preferably 0.3 parts by mass to 20 parts by mass. If the content of the antistatic agent is too low, it may not be able to impart sufficient antistatic properties to the functional layer. Furthermore, if the content of the antistatic agent is too high, the surface hardness of the functional layer may decrease, and its wear resistance may be reduced. It should be noted that when the functional layer contains an antistatic agent and, as described below, the functional layer is multilayered, it is preferable that the content of the antistatic agent in the antistatic agent-containing layer of the multilayered functional layer is within the above-mentioned range.

[0142] The functional layer may contain additives such as inorganic particles, organic particles, ultraviolet absorbers, antioxidants, light stabilizers, anti-glare agents, leveling agents, surfactants, lubricants, various sensitizers, flame retardants, tackifiers, polymerization inhibitors, and surface modifiers, as needed.

[0143] The functional layer can be a single layer or multiple layers.

[0144] The thickness of the functional layer is not particularly limited as long as it satisfies the aforementioned characteristics. For example, it is preferably 0.5 μm to 50 μm, more preferably 1.0 μm to 40 μm, and even more preferably 1.5 μm to 30 μm. If the functional layer is too thin, its surface hardness and wear resistance may decrease. Conversely, if the functional layer is too thick, its flexibility may be compromised. It should be noted that, as described above, by adjusting the thickness of the functional layer, the absolute value of the charge on the surface of the display device laminate after the rubber test can be adjusted to a predetermined range. Furthermore, when the functional layer is multilayered, it is preferable that the thickness of the layer located on the side opposite to the substrate layer in the multilayered functional layer is within the aforementioned range.

[0145] Here, the thickness of the functional layer can be the average of the thicknesses measured at any 10 points along the thickness direction of the laminate used in the display device, as observed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), or scanning transmission electron microscopy (STEM). It should be noted that the method for measuring the thicknesses of other layers in the laminate used in the display device can also be the same.

[0146] The functional layer can be disposed on one side of the substrate layer, wherein, in a laminate for a display device, the functional layer is preferably disposed on the outermost surface.

[0147] Examples of methods for forming a functional layer include coating a resin composition for a functional layer onto a substrate layer and then curing it.

[0148] 3. Substrate layer

[0149] The substrate layer in this invention is a transparent component that supports the aforementioned functional layer.

[0150] As a substrate layer, there are no particular limitations as long as it is transparent; examples include resin substrates and glass substrates.

[0151] (1) Resin substrate

[0152] The resin constituting the resin substrate is not particularly limited as long as a transparent resin substrate can be obtained; examples include polyimide-based resins, polyamide-based resins, and polyester-based resins. Examples of polyimide-based resins include polyimide, polyamide-imide, polyether-imide, and polyesterimide. Examples of polyester-based resins include polyethylene terephthalate, polyethylene terephthalate, polyethylene terephthalate, and polyethylene naphthalate. Among these, polyimide-based resins, polyamide-based resins, or mixtures thereof are preferred from the perspectives of flexural strength, excellent hardness, and transparency; polyimide-based resins are more preferred.

[0153] As for polyimide-based resins, there are no particular limitations as long as a transparent resin substrate can be obtained. Among the above, polyimide and polyamide-imide are preferred.

[0154] (a) Polyimide

[0155] Polyimide is obtained by reacting a tetracarboxylic acid component with a diamine component. As a polyimide, there are no particular limitations as long as it has transparency and rigidity. For example, from the perspective of having excellent transparency and excellent rigidity, it is preferred to have at least one structure selected from the group consisting of structures represented by the following general formula (1) and the following general formula (3).

[0156] [Chemistry 1]

[0157]

[0158] In the above general formula (1), R 1 R represents a tetravalent group that is a tetracarboxylic acid residue. 2 It represents at least one divalent group selected from the group consisting of trans-cyclohexanediamine residue, trans-1,4-bis(methylene)cyclohexanediamine residue, 4,4'-diaminodiphenyl sulfone residue, 3,4'-diaminodiphenyl sulfone residue, and the divalent group shown in the following general formula (2). n represents the number of repeating units, which is 1 or more.

[0159] [Chemistry 2]

[0160]

[0161] In the above general formula (2), R 3 and R 4 Each can be independently represented by a hydrogen atom, alkyl group, or perfluoroalkyl group.

[0162] [Chemistry 3]

[0163]

[0164] In the above general formula (3), R 5 R represents at least one tetravalent group selected from the group consisting of cyclohexanetetracarboxylic acid residues, cyclopentanetetracarboxylic acid residues, dicyclohexane-3,4,3',4'-tetracarboxylic acid residues, and 4,4'-(hexafluoroisopropylidene)phthalic acid residues. 6 This indicates a divalent group that acts as a diamine residue.

[0165] n' represents the number of repeating units, which is 1 or more.

[0166] It should be noted that "tetracarboxylic acid residue" refers to the residue after removing four carboxyl groups from a tetracarboxylic acid, indicating the same structure as the residue after removing the dianhydride structure from a tetracarboxylic dianhydride. Additionally, "diamine residue" refers to the residue after removing two amino groups from a diamine.

[0167] In the above general formula (1), R 1 The residue is a tetracarboxylic acid residue, which can be a residue obtained by removing the dianhydride structure from a tetracarboxylic dianhydride. Examples of tetracarboxylic dianhydrides include, for instance, the tetracarboxylic dianhydride described in International Publication No. 2018 / 070523. R in the above general formula (1) 1 From the perspective of improving transparency and rigidity, it is preferable to include at least one residue selected from the group consisting of 4,4'-(hexafluoroisopropylene)phthalic acid residue, 3,3',4,4'-biphenyltetracarboxylic acid residue, pyromellitic acid residue, 2,3',3,4'-biphenyltetracarboxylic acid residue, 3,3',4,4'-benzophenone tetracarboxylic acid residue, 3,3',4,4'-diphenyl sulfone tetracarboxylic acid residue, 4,4'-oxophthalic acid residue, cyclohexane tetracarboxylic acid residue, and cyclopentane tetracarboxylic acid residue. It is even more preferable to include at least one residue selected from the group consisting of 4,4'-(hexafluoroisopropylene)phthalic acid residue, 4,4'-oxophthalic acid residue, and 3,3',4,4'-diphenyl sulfone tetracarboxylic acid residue.

[0168] R 1The preferred residues are preferably contained in a total of 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more.

[0169] Additionally, as R 1 It is also preferred to use a combination of Group A and Group B, wherein Group A is a tetracarboxylic acid residue group suitable for improving rigidity, selected from at least one of the group consisting of 3,3',4,4'-biphenyltetracarboxylic acid residue, 3,3',4,4'-benzophenone tetracarboxylic acid residue and pyromellitic acid residue; and Group B is a tetracarboxylic acid residue group suitable for improving transparency, selected from at least one of the group consisting of 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 2,3',3,4'-biphenyltetracarboxylic acid residue, 3,3',4,4'-diphenylsulfone tetracarboxylic acid residue, 4,4'-oxophthalic acid residue, cyclohexanetetracarboxylic acid residue and cyclopentanetetracarboxylic acid residue.

[0170] In this case, regarding the content ratio of the tetracarboxylic acid residue group (Group A) suitable for improving rigidity and the tetracarboxylic acid residue group (Group B) suitable for improving transparency, the tetracarboxylic acid residue group (Group A) suitable for improving rigidity is preferably 0.05 moles or more and 9 moles or less, more preferably 0.1 moles or more and 5 moles or less, and even more preferably 0.3 moles or more and 4 moles or less, relative to 1 mole of the tetracarboxylic acid residue group (Group B) suitable for improving transparency.

[0171] R in the above general formula (1) 2 From the perspective of improving transparency and rigidity, it is preferable to select at least one divalent group selected from the group consisting of 4,4'-diaminodiphenyl sulfone residues, 3,4'-diaminodiphenyl sulfone residues and divalent groups represented by the above general formula (2), and more preferably selected from 4,4'-diaminodiphenyl sulfone residues, 3,4'-diaminodiphenyl sulfone residues, and R 3 and R 4 It is at least one divalent group in the group consisting of divalent groups represented by the above general formula (2) of perfluoroalkyl groups.

[0172] R in the above general formula (3) 5 From the perspective of improving transparency and rigidity, it is preferable to include 4,4'-(hexafluoroisopropylidene) phthalic acid residues, 3,3',4,4'-diphenyl sulfone tetracarboxylic acid residues and oxophthalic acid residues.

[0173] R 5 The preferred residues are preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more.

[0174] In the above general formula (3), R 6The residue is a diamine residue, which can be a residue obtained by removing two amino groups from a diamine. Examples of diamines include those described in International Publication No. 2018 / 070523. R in the above general formula (3) is... 6 From the perspective of improving transparency and rigidity, it is preferable to include residues selected from 2,2'-bis(trifluoromethyl)benzidine, bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4'-diaminodiphenyl sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, bis[4-(3-aminophenoxy)phenyl]sulfone, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether, 1,4-bis[4-amino-2-(trifluoromethyl)phenoxy]phenyl, 2,2-bis[4-(4- The group comprises at least one divalent group selected from the group consisting of amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane residue, 4,4'-diamino-2-(trifluoromethyl)diphenyl ether residue, 4,4'-diaminobenzoyl aniline residue, N,N'-bis(4-aminophenyl)terephthalamide residue and 9,9-bis(4-aminophenyl)fluorene residue, and more preferably includes at least one divalent group selected from the group consisting of 2,2'-bis(trifluoromethyl)benzidine residue, bis[4-(4-aminophenoxy)phenyl]sulfone residue and 4,4'-diaminodiphenyl sulfone residue.

[0175] R 6 The preferred residues are preferably contained in a total of 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more.

[0176] Additionally, as R 6 Preferably, group C is used in combination with group D, wherein group C is a diamine residue group suitable for improving rigidity selected from at least one of the group consisting of bis[4-(4-aminophenoxy)phenyl]sulfone residues, 4,4'-diaminobenzoyl aniline residues, N,N'-bis(4-aminophenyl)terephthalamide residues, p-phenylenediamine residues, m-phenylenediamine residues, and 4,4'-diaminodiphenylmethane residues; and group D is a diamine residue group selected from 2,2'-bis(trifluoromethyl)benzidine residues, 4,4'-diaminodiphenylsulfone residues, 2,2-bis[4-(4-aminophenyl)benzidine residues, and 4,4'-diaminodiphenyl sulfone residues. The group consisting of at least one of the following diamine residues suitable for improving transparency: phenoxy)phenyl]hexafluoropropane residue, bis[4-(3-aminophenoxy)phenyl]sulfone residue, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether residue, 1,4-bis[4-amino-2-(trifluoromethyl)phenoxy]benzene residue, 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane residue, 4,4'-diamino-2-(trifluoromethyl)diphenyl ether residue, and 9,9-bis(4-aminophenyl)fluorene residue.

[0177] In this case, regarding the content ratio of the diamine residue group (group C) suitable for improving rigidity to the diamine residue group (group D) suitable for improving transparency, the diamine residue group (group C) suitable for improving rigidity is preferably 0.05 moles or more and 9 moles or less, more preferably 0.1 moles or more and 5 moles or less, and more preferably 0.3 moles or more and 4 moles or less, relative to 1 mole of the diamine residue group (group D) suitable for improving transparency.

[0178] In the structures shown in general formulas (1) and (3) above, n and n' each independently represent the number of repeating units, which is 1 or more. The number of repeating units n in the polyimide can be appropriately selected according to the structure and is not particularly limited. The average number of repeating units can be, for example, 10 or more and 2000 or less, preferably 15 or more and 1000 or less.

[0179] Furthermore, polyimides may contain a polyamide structure in a portion thereof. Examples of polyamide structures that may be included include, for instance, polyamide-imide structures containing tricarboxylic acid residues such as trimellitic anhydride, or polyamide structures containing dicarboxylic acid residues such as terephthalic acid.

[0180] From the perspective of improving transparency and increasing surface hardness, as R 1 Or R 5 The tetravalent group of the tetracarboxylic acid residue, and as R 2 Or R 6 At least one of the divalent groups of the diamine residues preferably comprises an aromatic ring and includes at least one of the group consisting of (i) a fluorine atom, (ii) an aliphatic ring, and (iii) a structure in which the aromatic rings are linked together by a sulfonyl group or a fluorinated or unsubstituted alkylene group. By including at least one of the tetracarboxylic acid residues having an aromatic ring and the diamine residues having an aromatic ring in the polyimide, the molecular backbone becomes rigid, thereby increasing orientation and surface hardness. However, the rigid aromatic ring backbone tends to have an absorption wavelength that extends to longer wavelengths, and the transmittance in the visible light region tends to decrease. On the other hand, if the polyimide includes (i) a fluorine atom, the transparency is improved from the perspective of making it less likely for electronic states within the polyimide backbone to undergo charge transfer.

[0181] Furthermore, if the polyimide contains (ii) an aliphatic ring, its transparency is improved from the perspective of hindering the movement of charges within the framework by cleaving the conjugation of π electrons within the polyimide backbone. Additionally, if the polyimide contains (iii) a structure in which aromatic rings are linked to each other by sulfonyl groups or fluorinated or unsubstituted alkylene groups, its transparency is improved from the perspective of hindering the movement of charges within the framework by cleaving the conjugation of π electrons within the polyimide backbone.

[0182] Among them, focusing on improving transparency and surface hardness, as R 1 Or R 5 The tetravalent group of the tetracarboxylic acid residue, and as R 2 Or R 6 At least one of the divalent groups of the diamine residues preferably comprises an aromatic ring and a fluorine atom, as R 2 Or R 6 The divalent group of the diamine residue preferably includes an aromatic ring and a fluorine atom.

[0183] As a specific example of such polyimide, substances having the specific structure described in International Publication No. 2018 / 070523 can be cited.

[0184] Polyimide can be synthesized using well-known methods. Alternatively, commercially available substances can also be used as polyimide. Examples of commercially available polyimide include Neopulim (a registered trademark) manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0185] The weight-average molecular weight of polyimide is preferably 3,000 to 500,000, more preferably 5,000 to 300,000, and even more preferably 10,000 to 200,000. If the weight-average molecular weight is too small, sufficient strength may not be obtained. If the weight-average molecular weight is too large, the viscosity increases and the solubility decreases, so a substrate layer with a smooth surface and uniform thickness may not be obtained.

[0186] It should be noted that the weight-average molecular weight of polyimide can be determined by gel permeation chromatography (GPC). Specifically, polyimide is prepared into a 0.1% (w / w) N-methylpyrrolidone (NMP) solution, and the developing solvent is a 30 mmol% LiBr-NMP solution with a water content of less than 500 ppm. The determination is performed using a Tosoh-manufactured GPC apparatus (HLC-8120, column: SHODEX GPC LF-804) at a sample injection volume of 50 μL, a solvent flow rate of 0.4 mL / min, and a temperature of 37°C. The weight-average molecular weight is determined using a polystyrene standard sample of the same concentration as the sample.

[0187] (b) Polyamide imide

[0188] As for polyamide-imide, there are no particular limitations as long as a transparent resin substrate can be obtained. Examples include substances having the following first and second blocks: the first block comprises structural units from a dianhydride and structural units from a diamine, and the second block comprises structural units from an aromatic dicarbonyl compound and structural units from an aromatic diamine. In the aforementioned polyamide-imide, the dianhydride may, for example, comprise biphenyltetracarboxylic acid dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). Furthermore, the diamine may comprise bis(trifluoromethyl)benzidine (TFDB). That is, the aforementioned polyamide-imide has a structure formed by imidizing a polyamide-imide precursor having the following first and second blocks, where the first block is copolymerized from a monomer comprising a dianhydride and a diamine, and the second block is copolymerized from a monomer comprising an aromatic dicarbonyl compound and an aromatic diamine.

[0189] The aforementioned polyamide-imide, by having a first block containing an imide bond and a second block containing an amide bond, exhibits superior not only optical properties but also thermal and mechanical properties. In particular, by using bis(trifluoromethyl)benzidine (TFDB) as the diamine forming the first block, thermal stability and optical properties are improved. Furthermore, by using 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic acid dianhydride (BPDA) as the dianhydrides forming the first block, improved birefringence and ensured heat resistance are achieved.

[0190] The dianhydrides forming the first block contain two types of dianhydrides, namely 6FDA and BPDA. In the first block, polymers bonded with TFDB and 6FDA and polymers bonded with TFDB and BPDA can be distinguished based on different repeating units, or they can be arranged regularly within the same repeating unit, or they can be arranged completely randomly.

[0191] In the monomers forming the first block, BPDA and 6FDA are preferably contained as dianhydrides in a molar ratio of 1:3 to 3:1. This is because it not only ensures optical properties but also suppresses the reduction of mechanical properties and heat resistance, resulting in excellent birefringence.

[0192] The molar ratio of the first block to the second block is preferably 5:1 to 1:1. When the content of the second block is significantly low, the improved thermal stability and mechanical properties provided by the second block may not be fully realized. Furthermore, when the content of the second block is further higher than that of the first block, thermal stability and mechanical properties can be improved, but optical properties may deteriorate, such as reduced yellowness and transmittance, while birefringence may increase. It should be noted that the first block and the second block can be random copolymers or block copolymers. The repeating units of the blocks are not particularly limited.

[0193] Examples of aromatic dicarbonyl compounds forming the second block include, for example, one or more selected from the group consisting of p-Terephthaloyl chloride (TPC), terephthalic acid, isophthaloyl dichloride, and 4,4'-benzoyl dichloride. Preferably, it can be one or more selected from p-Terephthaloyl chloride (TPC) and isophthaloyl dichloride.

[0194] Examples of diamines that form the second block include 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (HFBAPP), bis(4-(4-aminophenoxy)phenyl)sulfone (BAPS), bis(4-(3-aminophenoxy)phenyl)sulfone (BAPSM), 4,4'-diaminodiphenyl sulfone (4DDS), 3,3'-diaminodiphenyl sulfone (3DDS), 2,2-bis(4-(4-aminophenoxy)phenylpropane (BAPP), 4,4'-diaminodiphenylpropane (6HDA), and 1,3-bis(4-aminophenoxy)phenyl (134A). The group consisting of one or more diamines having a soft group, including PB), 1,3-bis(3-aminophenoxy)benzene (133APB), 1,4-bis(4-aminophenoxy)biphenyl (BAPB), 4,4'-bis(4-amino-2-trifluoromethylphenoxy)biphenyl (6FAPBP), 3,3-diamino-4,4-dihydroxydiphenyl sulfone (DABS), 2,2-bis(3-amino-4-hydroxyoxyphenyl)propane (BAP), 4,4'-diaminodiphenylmethane (DDM), 4,4'-oxodiphenylamine (4-ODA), and 3,3'-oxodiphenylamine (3-ODA).

[0195] When using aromatic dicarbonyl compounds, high thermal stability and mechanical properties are easily achieved, but high birefringence is sometimes exhibited due to the benzene ring within the molecular structure. Therefore, to suppress the reduction in birefringence caused by the second block, diamines with a flexible group introduced into the molecular structure are preferred. Specifically, diamines are more preferably selected from one or more of bis(4-(3-aminophenoxy)phenyl)sulfone (BAPSM), 4,4'-diaminodiphenyl sulfone (4DDS), and 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (HFBAPP). In particular, diamines with longer flexible groups (such as BAPSM) and meta-substituents exhibit superior birefringence.

[0196] The polyamide-imide precursor containing the first and second blocks described below has a weight-average molecular weight, as determined by GPC, preferably between 200,000 and 215,000, and a viscosity, preferably between 2,400 poise and 2,600 poise. The first block is a copolymer of a dianhydride containing biphenyltetracarboxylic acid dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) with a diamine containing bis(trifluoromethyl)benzidine (TFDB), and the second block is a copolymer of an aromatic dicarbonyl compound with an aromatic diamine.

[0197] Polyamide-imide can be obtained by imidizing a polyamide-imide precursor. Alternatively, polyamide-imide films can be obtained using polyamide-imide. For methods of imidizing the polyamide-imide precursor and methods of manufacturing polyamide-imide films, please refer, for example, to Japanese Patent Publication No. 2018-506611.

[0198] (2) Glass substrate

[0199] As for the glass that constitutes the glass substrate, there are no particular limitations as long as it is transparent; examples include silicate glass and silica glass. Among these, borosilicate glass, aluminosilicate glass, and aluminoborosilicate glass are preferred, and alkali-free glass is more preferred. Commercially available glass substrates include, for example, Nippon Electric Glass's G-Leaf ultra-thin sheet glass and Matsunami Glass Industry Co., Ltd.'s ultra-thin film glass.

[0200] Furthermore, the glass constituting the glass substrate is preferably chemically strengthened glass. Chemically strengthened glass has excellent mechanical strength and can be thinned accordingly, making it preferred from this perspective. Chemically strengthened glass is typically glass in which sodium is replaced with potassium or the like near the surface of the glass, resulting in a partial exchange of ions, thereby enhancing the mechanical properties through a chemical method, and creating a compressive stress layer on the surface.

[0201] Examples of glasses that form the substrate of chemically strengthened glass include aluminosilicate glass, soda-lime glass, borosilicate glass, lead glass, alkaline barium glass, and aluminoborosilicate glass.

[0202] Commercially available products that serve as substrates for chemically strengthened glass include Corning's Gorilla Glass, AGC's Dragontrail, and Schott's chemically strengthened glass.

[0203] (3) Composition of the substrate layer

[0204] As the substrate layer, the preferred options are a polyimide resin substrate containing a polyimide resin or a glass substrate. This is because it is possible to produce a substrate layer with bending resistance, excellent hardness, and transparency.

[0205] There is no particular limitation on the thickness of the substrate layer, as long as it is flexible. It can be selected appropriately according to the type of substrate layer.

[0206] The thickness of the resin substrate is preferably 10 μm or more and 100 μm or less, more preferably 25 μm or more and 80 μm or less. By keeping the thickness of the resin substrate within the above range, good flexibility and sufficient hardness can be obtained. In addition, curling of the laminate for the display device can be suppressed. Furthermore, it is preferable to achieve lightweighting of the laminate for the display device.

[0207] The thickness of the glass substrate is preferably 200 μm or less, more preferably 15 μm or more and 100 μm or less, even more preferably 20 μm or more and 90 μm or less, and particularly preferably 25 μm or more and 80 μm or less. By keeping the thickness of the glass substrate within the above range, good flexibility and sufficient hardness can be obtained. In addition, curling of the laminate for the display device can be suppressed. Furthermore, it is preferable in terms of lightweighting the laminate for the display device.

[0208] 4. Second functional layer

[0209] The laminate for the display device in this invention can have a second functional layer between the substrate layer and the functional layer, or on the side of the functional layer opposite to the substrate layer. Examples of the second functional layer include, for example, a hard coating layer, an anti-reflective layer, an anti-glare layer, an anti-scattering layer, and a base coating layer.

[0210] Furthermore, the second functional layer can be a single layer or multiple layers. Additionally, the second functional layer can be a layer with a single function, or it can consist of multiple layers with different functions.

[0211] (1) Hard coating

[0212] For example, Figure 4 As shown, the laminate for the display device in this invention can have a hard coating layer 4 between the substrate layer 2 and the functional layer 3. The hard coating layer is a component used to improve surface hardness. By configuring the hard coating layer, scratch resistance can be improved. In particular, when the substrate layer is a resin substrate, the scratch resistance can be effectively improved by configuring the hard coating layer.

[0213] Materials that can be used as hard coatings include, for example, organic materials, inorganic materials, and organic-inorganic composite materials.

[0214] The material of the hard coating is preferably an organic material. Specifically, the hard coating preferably comprises a cured product of a resin composition containing a polymerizable compound. The cured product of the resin composition containing the polymerizable compound can be obtained by polymerizing the polymerizable compound using a polymerization initiator and a known method, as needed.

[0215] It should be noted that the polymerizable compounds can be the same substances described in the above-mentioned functional layer section, therefore the description here is omitted.

[0216] The hard coating may also contain a polymerization initiator as needed. It should be noted that the polymerization initiator can be the same substance described in the section on functional layers above, therefore, the description here is omitted.

[0217] Furthermore, the hard coating layer may contain an antistatic agent. Where the functional layer does not contain an antistatic agent, it is preferable that the hard coating layer contains an antistatic agent. This imparts antistatic properties to the laminate for display devices. Moreover, by adjusting the content of the antistatic agent, the absolute value of the charge on the functional layer side of the laminate for display devices after a rubber test can be adjusted to a specified range.

[0218] The type and content of the antistatic agent can be the same as those in the functional layer mentioned above.

[0219] The hard coating may contain further additives as needed. These additives are selected appropriately based on the function imparted to the hard coating and are not particularly limited. Examples include inorganic particles, organic particles, ultraviolet absorbers, infrared absorbers, antifouling agents, antiglare agents, leveling agents, surfactants, lubricants, various sensitizers, flame retardants, tackifiers, polymerization inhibitors, antioxidants, light stabilizers, and surface modifiers.

[0220] The thickness of the hard coating can be appropriately selected based on the function of the hard coating and the application of the laminate for the display device. The thickness of the hard coating is preferably 0.5 μm to 50 μm, more preferably 1.0 μm to 40 μm, even more preferably 1.5 μm to 30 μm, and particularly preferably 2 μm to 20 μm. If the thickness of the hard coating is within the above range, sufficient hardness as a hard coating can be obtained.

[0221] As a method for forming a hard coating, one example is a method of coating a hard coating resin composition containing the polymeric compound described above onto the substrate layer and then curing it.

[0222] (2) Anti-reflective layer

[0223] The laminate for the display device in this invention may have an anti-reflective layer as a second functional layer. This anti-reflective layer is typically disposed on the surface of the functional layer opposite to the substrate layer.

[0224] Anti-reflective layers can be composed of a single layer or multiple layers.

[0225] As an anti-reflective layer, general anti-reflective layers can be used, such as single-layer films containing materials with a refractive index lower than that of the hard coating layer, multilayer films having high-refractive-index layers and low-refractive-index layers from the hard coating layer side, multilayer films having alternating high-refractive-index layers and low-refractive-index layers from the hard coating layer side, and multilayer films having intermediate-refractive-index layers, high-refractive-index layers and low-refractive-index layers sequentially from the hard coating layer side.

[0226] When the antireflective layer is a single-layer film, any material contained in the single-layer film can have a refractive index lower than that of the hard coating layer, such as magnesium fluoride.

[0227] Furthermore, when the antireflective layer is a multilayer film, the refractive index of the low-refractive-index layer is preferably 1.45 or less, more preferably 1.40 or less. By setting the refractive index of the low-refractive-index layer within the above range, the antireflective properties become good. In fact, the lower limit of the refractive index of the low-refractive-index layer is 1.10 or more.

[0228] Examples of low refractive index layers include layers containing hydrolyzed condensates of metal alkoxides, layers containing resins with low refractive index, layers containing particles with low refractive index, and layers containing binder resins and particles with low refractive index.

[0229] Hydrolytic condensation polymers of metal alkoxides can be obtained, for example, by the sol-gel method.

[0230] Examples of resins with low refractive index include fluoropolymers.

[0231] In addition, the thickness of the low refractive index layer is preferably about 1 / 4 of the wavelength region of visible light (about 100 nm), so for example, it is preferably 60 nm or more and 200 nm or less, more preferably 75 nm or more and 180 nm or less, and even more preferably 90 nm or more and 150 nm or less.

[0232] Examples of methods for forming low-refractive-index layers include wet and dry methods. Examples of wet methods include methods using metal alkoxides or the like to form the layer via sol-gel, methods using low-refractive-index resins, and methods using compositions containing binder resins and low-refractive-index particles to form the layer. Examples of dry methods include methods using low-refractive-index particles to form the layer via physical vapor deposition or chemical vapor deposition. Wet methods offer superior production efficiency, and methods using compositions containing binder resins and low-refractive-index particles to form the layer are preferred.

[0233] Furthermore, the refractive index of the high-refractive-index layer is preferably 1.55 or higher and 1.85 or lower, more preferably 1.58 or higher and 1.70 or lower. By making the refractive index of the high-refractive-index layer above a specified value, the anti-reflective properties become good. In fact, the upper limit of the high-refractive-index layer is 1.85 or lower.

[0234] Examples of high refractive index layers include those containing binder resin and high refractive index particles.

[0235] Examples of high refractive index particles include antimony pentoxide, zinc oxide, titanium oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, yttrium oxide, and zirconium oxide.

[0236] The average particle size of the high refractive index particles is preferably 5 nm or more and 200 nm or less, more preferably 5 nm or more and 100 nm or less, and even more preferably 10 nm or more and 80 nm or less. By making the average particle size 5 nm or more, particle aggregation can be easily suppressed, and by making the average particle size 200 nm or less, whitening caused by particle diffusion and resulting reduction in visual recognizability can be easily suppressed.

[0237] From the perspective of balancing the high refractive index of the coating and the strength of the coating, the content of high refractive index particles is preferably 50 parts by mass and less than 500 parts by mass relative to 100 parts by mass of the adhesive resin, more preferably 100 parts by mass and less than 450 parts by mass, and even more preferably 200 parts by mass and less than 430 parts by mass.

[0238] Examples of curable resin compositions that can be used as binder resins in high-refractive-index layers include cured products of such compositions. The same material as the curable resin compositions exemplified in hard coatings can be used as the curable resin composition; photocurable resin compositions are preferred.

[0239] Furthermore, the thickness of the high refractive index layer is preferably 200 nm or less, more preferably 50 nm or more and 180 nm or less, and even more preferably 90 nm or more and 160 nm or less. By making the thickness of the high refractive index layer within the above range, low reflectivity can be exhibited in a wide wavelength region within the visible light region (380 nm to 780 nm).

[0240] As a method for forming a high refractive index layer, one example is a method of forming a high refractive index layer by coating a composition containing a binder resin and high refractive index particles.

[0241] The thickness of the anti-reflective layer can be the same as that of a regular anti-reflective layer, and can be appropriately selected based on the layer composition of the anti-reflective layer.

[0242] Methods for forming anti-reflective layers include coating and vapor deposition, which can be selected appropriately based on the material of the anti-reflective layer.

[0243] 5. Shock Absorption Layer

[0244] The laminate for a display device according to the present invention can have an impact-absorbing layer on the side of the substrate layer opposite to the functional layer, or between the substrate layer and the functional layer. By configuring the impact-absorbing layer, the laminate for a display device can absorb the impact when an impact is applied, thereby improving its impact resistance. In addition, when the substrate layer is a glass substrate, cracking of the glass substrate can be suppressed.

[0245] There are no particular limitations on the materials used for the impact-absorbing layer, as long as it possesses both impact absorption properties and transparency. Examples include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), urethane resins, epoxy resins, polyimides, polyamide-imides, acrylic resins, triacetyl cellulose (TAC), and silicone resins. These materials can be used individually or in combination of two or more.

[0246] The impact-absorbing layer may contain further additives as needed. Examples of additives include inorganic particles, organic particles, UV absorbers, antioxidants, light stabilizers, surfactants, and adhesion enhancers.

[0247] The thickness of the impact-absorbing layer can be any thickness that can absorb the impact, for example, preferably 7μm or more and 150μm or less, more preferably 10μm or more and 120μm or less, and even more preferably 15μm or more and 100μm or less.

[0248] As an impact-absorbing layer, a resin film can be used, for example. Alternatively, an impact-absorbing layer can be formed, for example, by coating the aforementioned substrate layer with an impact-absorbing layer composition.

[0249] 6. Apply adhesive layer

[0250] For example, Figure 5 As shown, the display device laminate of the present invention has an adhesive layer 6 on the side of the substrate layer 2 opposite to the functional layer 3. The adhesive layer can be used to attach the display device laminate to, for example, a display panel.

[0251] As for the adhesive used for bonding, there are no particular limitations as long as the adhesive is transparent and can be used to bond the display device to the display panel, etc. Examples include thermosetting adhesives, UV-curing adhesives, two-component curing adhesives, hot melt adhesives, pressure-sensitive adhesives (so-called adhesives), etc.

[0252] Among them, for example, Figure 6 As shown, an impact-absorbing layer 5 is disposed on the side of the substrate layer 2 opposite to the functional layer 3, and an adhesive layer 6 for attachment is disposed on the side of the impact-absorbing layer 5 opposite to the substrate layer 2. An interlayer adhesive layer 7 (described later) is disposed between the substrate layer 2 and the impact-absorbing layer 5. Preferably, the adhesive layer for attachment and the interlayer adhesive layer contain a pressure-sensitive adhesive, i.e., a pressure-sensitive adhesive layer is preferred. Generally, the pressure-sensitive adhesive layer is a relatively soft layer among adhesive layers containing the aforementioned adhesive. By disposing the impact-absorbing layer between relatively soft pressure-sensitive adhesive layers, impact resistance can be improved. This is believed to be because the pressure-sensitive adhesive layer is relatively soft and easily deformable. Therefore, when an impact is applied to the laminated body for the display device, the deformation of the impact-absorbing layer is not suppressed by the pressure-sensitive adhesive layer, and the impact-absorbing layer is easily deformable, thus achieving a greater impact absorption effect.

[0253] Pressure-sensitive adhesives used as pressure-sensitive bonding layers can include, for example, acrylic adhesives, silicone adhesives, rubber adhesives, and urethane adhesives, which can be appropriately selected based on the material of the aforementioned impact-absorbing layer. Among these, acrylic adhesives are preferred because they offer excellent transparency, weather resistance, durability, and heat resistance, while also being cost-effective.

[0254] The thickness of the adhesive layer for attachment is preferably 10 μm to 100 μm, more preferably 25 μm to 80 μm, and even more preferably 40 μm to 60 μm. If the thickness of the adhesive layer for attachment is too thin, it may not be possible to adequately bond the laminate for the display device to the display panel, etc. In addition, if the adhesive layer for attachment is a pressure-sensitive adhesive layer, if the thickness of the adhesive layer for attachment is too thin, it may not be possible to achieve the effect of easily deforming the impact-absorbing layer when an impact is applied to the laminate for the display device. On the other hand, if the thickness of the adhesive layer for attachment is too thick, the flexibility may be compromised.

[0255] As an adhesive layer for attachment, an adhesive film can be used, for example. Alternatively, an adhesive composition can be applied to a support or substrate layer to form an adhesive layer for attachment.

[0256] 7. Interlayer adhesive layer

[0257] In the laminated body for display devices of the present invention, interlayer adhesive layers may be disposed between each layer.

[0258] The adhesive used as an interlayer bonding layer can be the same as the adhesive used for the bonding layer described above.

[0259] In the case described above, when an impact-absorbing layer is disposed on the side of the substrate layer opposite to the functional layer, and an adhesive layer for attachment is disposed on the side of the impact-absorbing layer opposite to the substrate layer, and an interlayer adhesive layer is disposed between the substrate layer and the impact-absorbing layer, the adhesive layer for attachment and the interlayer adhesive layer preferably contain a pressure-sensitive adhesive, that is, a pressure-sensitive adhesive layer is preferred.

[0260] The pressure-sensitive adhesive layer can be the same as the pressure-sensitive adhesive layer used in the above-mentioned adhesive layer for application.

[0261] The thickness and formation method of the interlayer adhesive layer can be the same as those of the adhesive layer used for attachment described above.

[0262] 8. Other aspects of laminates for display devices

[0263] The thickness of the laminate for the display device in this invention is preferably 10 μm or more and 500 μm or more, more preferably 20 μm or more and 400 μm or more, and even more preferably 30 μm or more and 300 μm or more. If the thickness of the laminate for the display device is within the above range, flexibility can be improved.

[0264] The laminate for display devices of the present invention can be used as a front panel in a display device, positioned closer to the viewer than the display panel. Specifically, the laminate for display devices of the present invention is suitable for use as a front panel in flexible display devices such as foldable displays, rollable displays, and bendable displays. In particular, the laminate for display devices of the present invention is suitable for use as a front panel in foldable displays because it improves the wear resistance of the bent portion.

[0265] In addition, the display device laminate of the present invention can be used in the front panel of display devices such as smartphones, tablet terminals, wearable terminals, personal computers, televisions, digital signage, public information displays (PIDs), and vehicle displays.

[0266] B. Display device

[0267] The display device of the present invention includes a display panel and a display device laminate disposed on the observer side of the display panel.

[0268] Figure 7 This is a schematic cross-sectional view illustrating an example of a display device according to the present invention. Figure 7 As shown, the display device 20 includes a display panel 21 and a display device laminate 1 disposed on the observer side of the display panel 21. In the display device 20, the display device laminate 1 and the display panel 21 can be bonded together, for example, by means of an adhesive layer 6 for attaching the display device laminate 1.

[0269] When the display device of the present invention is disposed on the surface of the display device using a laminate, it is disposed with the functional layer on the outside and the substrate layer on the inside.

[0270] There are no particular limitations on the method of disposing the display device of the present invention on the surface of the display device using a laminate, and methods such as using an adhesive layer can be cited as examples.

[0271] Examples of display panels used in display devices such as organic EL display devices and liquid crystal display devices can be cited as display panels in this invention.

[0272] The display device of the present invention can have a touch panel component between the display panel and the display device laminate.

[0273] The display device in this invention is preferably a flexible display device such as a foldable display, a rollable display, or a bendable display.

[0274] Furthermore, the display device of the present invention is preferably foldable. That is, the display device of the present invention is preferably a foldable display. The curved portion of the display device of the present invention has excellent wear resistance, making it suitable as a foldable display.

[0275] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are illustrative examples; any embodiment that has a substantially similar structure to the technical concept described in the claims of the present invention and can achieve the same effect is included within the technical scope of the present invention.

[0276] Example

[0277] The following examples and comparative examples are shown to further illustrate the present invention.

[0278] [Example 1]

[0279] (1) Formation of hard coating A

[0280] First, the components are mixed in the manner shown below to obtain resin composition 1 for hard coating.

[0281] (Composition of resin composition 1 for hard coating)

[0282] • Carbamate acrylate (product name "8UX-141A", manufactured by Dacheng Fine Chemical Co., Ltd.): 100 parts by weight (converted value of 100% solids content).

[0283] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 4 parts by weight

[0284] Leveling agent (product name "BYK-UV3535", manufactured by BYK Chemicals Japan): 0.5 parts by weight (converted value of 100% solids).

[0285] Methyl isobutyl ketone: 250 parts by weight

[0286] Next, using an 80 μm thick polyimide film (product name "Neopulim", manufactured by Mitsubishi Gas Chemical Co., Ltd.) as the substrate layer, the aforementioned resin composition 1 for hard coating was applied onto the substrate layer using a bar coater to form a coating film. Then, the coating film was heated to 80°C for 1 minute to evaporate the solvent in the coating film. An ultraviolet irradiation device (manufactured by Fusion UV Systems Japan, using an H-bulb light source) was used, with an oxygen concentration of 100 ppm or less and a cumulative light intensity of 70 mJ / cm². 2 The coating is cured by irradiating it with ultraviolet light to form a hard coating A with a thickness of 9.0 μm as the second functional layer.

[0287] (2) Formation of hard coating B

[0288] First, the components are mixed in the manner shown below to obtain resin composition 2 for hard coating.

[0289] (Composition of resin composition 2 for hard coating)

[0290] • Carbamate acrylate (product name "8UX-015A", manufactured by Dacheng Fine Chemical Co., Ltd.): 100 parts by weight (converted value of 100% solids content).

[0291] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 4 parts by weight

[0292] • Antifouling agent (product name "DAC-HP", manufactured by Daikin): 0.5 parts by weight (converted from 100% solids content)

[0293] • Antistatic agent (product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 1.5 parts by weight (converted from 100% solid content).

[0294] Methyl isobutyl ketone: 250 parts by weight

[0295] Next, the resin composition 2 for the hard coating is applied onto the hard coating layer A using a bar coater to form a coating film. Then, the coating film is heated to 50°C for 1 minute to evaporate the solvent. An ultraviolet irradiation device (FusionUV Systems Japan, H-bulb light source) is used, with an oxygen concentration of 100 ppm or less and a cumulative light intensity of 360 mJ / cm². 2 The coating is cured by irradiating it with ultraviolet light to form a hard coating layer B with a thickness of 3.0 μm as a functional layer. In this way, a laminate having a substrate layer, a hard coating layer A (second functional layer), and a hard coating layer B (functional layer) is obtained.

[0296] [Comparative Example 1]

[0297] In the formation of the hard coating layer B (functional layer), the following hard coating resin composition 3 is used, and the laminate is prepared in the same manner as in Example 1.

[0298] (Composition of resin composition 3 for hard coating)

[0299] • Carbamate acrylate (product name "8UX-141A", manufactured by Dacheng Fine Chemical Co., Ltd.): 100 parts by weight (converted value of 100% solids content).

[0300] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGMresins B.V.): 4 parts by weight

[0301] • Antifouling agent (product name "DAC-HP", manufactured by Daikin): 0.5 parts by weight (converted from 100% solids content)

[0302] Methyl isobutyl ketone: 250 parts by weight

[0303] [Example 2]

[0304] As the substrate layer, a 50 μm thick PET film (manufactured by Toyobo Co., Ltd., "COSMOSHINE A4160") was used, and the laminate was otherwise fabricated in the same manner as in Example 1.

[0305] [Example 3]

[0306] In the formation of the hard coating layer B (functional layer), the following hard coating resin composition 4 is used to make the thickness 4.0 μm, and the laminate is otherwise made in the same manner as in Example 2.

[0307] (Composition of resin composition 4 for hard coating)

[0308] • Carbamate acrylate (product name "8UX-141A", manufactured by Dacheng Fine Chemical Co., Ltd.): 100 parts by weight (converted value of 100% solids content).

[0309] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 4 parts by weight

[0310] • Antifouling agent (product name "DAC-HP", manufactured by Daikin): 0.5 parts by weight (converted from 100% solids content)

[0311] • Antistatic agent (product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 2 parts by weight (converted from 100% solid content)

[0312] Methyl isobutyl ketone: 250 parts by weight

[0313] [Example 4]

[0314] No hard coating A (second functional layer) is formed, and the above-mentioned hard coating resin composition 4 is used in the formation of hard coating B (functional layer) to make the thickness 3.5 μm. Otherwise, the laminate is made in the same manner as in Example 2.

[0315] [Example 5]

[0316] In the formation of the hard coating layer B (functional layer), the thickness is 3.3 μm, and the laminate is otherwise fabricated in the same manner as in Example 3.

[0317] [Example 6]

[0318] In the formation of the hard coating layer B (functional layer), the thickness is 3.8 μm, and the laminate is otherwise fabricated in the same manner as in Example 3.

[0319] [Example 7]

[0320] In the formation of the hard coating layer B (functional layer), the following hard coating resin composition 5 is used to make the thickness 3.5 μm, and the laminate is otherwise made in the same manner as in Example 3.

[0321] (Composition of resin composition 5 for hard coating)

[0322] • Carbamate acrylate (product name "8UX-141A", manufactured by Dacheng Fine Chemical Co., Ltd.): 50 parts by weight (converted value of 100% solids content).

[0323] • Carbamate acrylate (product name "8UX-015A", manufactured by Dacheng Fine Chemical Co., Ltd.): 50 parts by weight (converted value of 100% solids content).

[0324] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 4 parts by weight

[0325] • Antifouling agent (product name "DAC-HP", manufactured by Daikin): 0.5 parts by weight (converted from 100% solids content)

[0326] • Antistatic agent (product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 2 parts by weight (converted from 100% solid content)

[0327] Methyl isobutyl ketone: 250 parts by weight

[0328] [Example 8]

[0329] The laminate was prepared in the same manner as in Example 2, except that a hard coating resin composition 6 containing an antistatic agent in the second functional layer was used.

[0330] (Composition of resin composition 6 for hard coating)

[0331] • Carbamate acrylate (product name "8UX-141A", manufactured by Dacheng Fine Chemical Co., Ltd.): 100 parts by weight (converted value of 100% solids content).

[0332] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 4 parts by weight

[0333] Leveling agent (product name "BYK-UV3535", manufactured by BYK Chemicals Japan): 0.5 parts by weight (converted value of 100% solids).

[0334] • Antistatic agent (product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 2.5 parts by weight (converted from 100% solid content)

[0335] Methyl isobutyl ketone: 250 parts by weight

[0336] [Example 9]

[0337] The laminate is prepared in the same manner as in Example 8, except that a hard coating resin composition 7 that does not utilize antistatic agents is used in the functional layer.

[0338] (Composition of resin composition 7 for hard coating)

[0339] • Carbamate acrylate (product name "8UX-015A", manufactured by Dacheng Fine Chemical Co., Ltd.): 100 parts by weight (converted value of 100% solids content).

[0340] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 4 parts by weight

[0341] • Antifouling agent (product name "DAC-HP", manufactured by Daikin): 0.5 parts by weight (converted from 100% solids content)

[0342] Methyl isobutyl ketone: 250 parts by weight

[0343] [Example 10]

[0344] The thickness of the functional layer is 5.8 μm, and the laminate is fabricated in the same manner as in Example 9.

[0345] [Example 11]

[0346] The thickness of the functional layer is 9.4 μm, and the laminate is fabricated in the same manner as in Example 9.

[0347] [Example 12]

[0348] First, the resin composition 8 for hard coating is applied to the hard coating layer A (second functional layer) of Example 2 using a bar coater to form a coating film. Then, the coating film is heated to 80°C for 1 minute to evaporate the solvent. An ultraviolet irradiation device (Fusion UV Systems Japan, H-bulb light source) is used, with an oxygen concentration of 100 ppm or less and a cumulative light intensity of 70 mJ / cm². 2 The coating is cured by irradiating it with ultraviolet light to form a hard coating layer B (functional layer) with a thickness of 3.0 μm.

[0349] (Composition of resin composition 8 for hard coating)

[0350] • Carbamate acrylate (product name "8UX-015A", manufactured by Dacheng Fine Chemical Co., Ltd.): 100 parts by weight (converted value of 100% solids content).

[0351] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 4 parts by weight

[0352] Leveling agent (product name "BYK-UV3535", manufactured by BYK Chemicals Japan): 0.5 parts by weight (converted value of 100% solids).

[0353] • Antistatic agent (product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 1.5 parts by weight (converted from 100% solid content).

[0354] Methyl isobutyl ketone: 250 parts by weight

[0355] Next, on the aforementioned hard coating layer B (functional layer), an anti-reflective layer (low refractive index) with a thickness of 100 nm is formed under the following processing conditions using an anti-reflective layer (low refractive index) composition with the following composition, to obtain a laminate.

[0356] (Composition of the composition for anti-reflective layer (low refractive index))

[0357] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 3 parts by weight

[0358] • Carbamate acrylate (product name "8UX-047A", manufactured by Dacheng Fine Chemical Co., Ltd.): 25 parts by weight

[0359] • Multifunctional acrylate (product name "M-510", manufactured by Dong-A Synthetic Co., Ltd.): 45 parts by weight

[0360] • Pentaerythritol triacrylate and pentaerythritol tetraacrylate (product name "M-450", manufactured by Dong-A Synthetic Co., Ltd.): 30 parts by weight

[0361] • Low refractive index particles (hollow silica, average primary particle size 50nm, manufactured by Nichibukai Catalyst Chemical Co., Ltd.): 120 parts by weight (100% solids conversion).

[0362] • Low refractive index particles (silica, average primary particle size 12nm, manufactured by Nissan Chemical Industries, Ltd.): 15 parts by weight (100% solids conversion).

[0363] Methyl isobutyl ketone: 270 parts by weight

[0364] Isopropanol: 40 parts by weight

[0365] (Processing conditions)

[0366] After heating at 90℃ for 1 minute, the oxygen concentration was below 100 ppm and the cumulative light intensity was 500 mJ / cm². 2 It is irradiated with ultraviolet light in this way.

[0367] [Example 13]

[0368] On the hard coating layer B (functional layer) described in Example 12, an anti-reflective layer (high refractive index) with a thickness of 80 nm was fabricated using an anti-reflective layer (high refractive index) composition with the following composition under the following processing conditions. Next, an anti-reflective layer (low refractive index) of the same type as the anti-reflective layer fabricated in Example 12 was fabricated to obtain a laminate.

[0369] (Composition of the composition for anti-reflective layer (high refractive index))

[0370] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 3 parts by weight

[0371] • Pentaerythritol (tri / tetra) acrylate (product name "PETIA", manufactured by Daicel-Allnex): 80 parts by weight

[0372] • Multifunctional acrylate (product name "M-510", manufactured by Dong-A Synthetic Co., Ltd.): 20 parts by weight

[0373] • High refractive index particles (zirconia, average primary particle size 20 nm, manufactured by CIK NanoTek): 120 parts by weight (100% solids conversion).

[0374] Methyl isobutyl ketone: 270 parts by weight

[0375] Isopropanol: 40 parts by weight

[0376] (Processing conditions)

[0377] After heating at 70℃ for 1 minute, the oxygen concentration was below 100 ppm and the cumulative light intensity was 60 mJ / cm². 2 It is irradiated with ultraviolet light in this way.

[0378] [Example 14]

[0379] The thickness of the antireflective layer (high refractive index) was 190 nm, and otherwise the laminate was obtained in the same manner as in Example 13.

[0380] [Comparative Example 2]

[0381] In the formation of the hard coating layer B (functional layer), the thickness is 3.0 μm. Otherwise, the laminate is fabricated in the same manner as in Example 4.

[0382] [Comparative Example 3]

[0383] In the formation of the hard coating layer B (functional layer), the thickness is 2.5 μm, and the laminate is otherwise fabricated in the same manner as in Example 3.

[0384] [Comparative Example 4]

[0385] In the formation of the hard coating layer B (functional layer), the following hard coating resin composition 9 is used to make the thickness 2.5 μm, and the laminate is otherwise made in the same manner as in Example 3.

[0386] (Composition of resin composition 9 for hard coating)

[0387] • Carbamate acrylate (product name "8UX-141A", manufactured by Dacheng Fine Chemical Co., Ltd.): 100 parts by weight (converted value of 100% solids content).

[0388] • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 4 parts by weight

[0389] • Antifouling agent (product name "DAC-HP", manufactured by Daikin): 0.5 parts by weight (converted from 100% solids content)

[0390] • Antistatic agent (product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 10 parts by weight (converted from 100% solid content)

[0391] Methyl isobutyl ketone: 250 parts by weight

[0392] [Comparative Example 5]

[0393] The thickness of the functional layer is 10.3 μm, and the laminate is fabricated in the same manner as in Example 9.

[0394] [evaluate]

[0395] (1) Charge after the rubber test

[0396] The following rubber test was performed on the functional layer side surface of the laminates of the embodiments and comparative examples, and the charge amount of the functional layer side surface of the laminates after the rubber test was measured.

[0397] First, static electricity was removed by contacting the glass plate serving as the test bench with the ion generator for 1 minute at 23±5℃ and 40±10%RH. Next, a 20mm×80mm laminate was prepared, and static electricity was removed by contacting the ion generator with both sides of the laminate at 23±5℃ and 40±10%RH for 30 to 60 seconds.

[0398] Next, the ends of the laminate were fixed to a glass plate with transparent tape, and a rubber test was performed on the functional layer side of the laminate. Specifically, a 6mm diameter rubber manufactured by Minoan was inserted into a fixture with a 6mm diameter hole, with the front end of the rubber protruding 4mm. The fixture with the rubber was installed in a vibratory friction fastness tester (product name "AB-301", manufactured by TESTERSANGYO). Under the conditions of temperature 23±5℃, humidity 40±10%RH, load 9.8N, moving speed 80mm / s, and moving distance 40mm, the rubber was used to rub the functional layer side of the laminate 2500 times.

[0399] Next, the laminated body after the rubber test was placed in a Faraday cage, and the charge was measured. At this time, the laminated body after the rubber test was lifted using insulating and non-magnetic tweezers. Furthermore, after lifting the laminated body after the rubber test, the charge was measured without contact with other fixed surfaces. The Faraday cage used was the Kasuga Electric Corporation Faraday cage "KQ-1400". The ion generator used was the Kasuga Electric Corporation fan-type ion generator "KD-750B". The tweezers used were the Kenis Corporation ESD (static discharge control) tweezers "P-643-S".

[0400] (2) Friction before and after the rubber test

[0401] The above-described rubber test was performed on the functional layer side surface of the laminates of the embodiments and comparative examples, and the frictional force of the functional layer side surface of the laminates to the rubber was measured before and after the rubber test.

[0402] In the determination of the frictional force of the rubber, a 6mm diameter rubber manufactured by Minoan was used. The rubber was inserted into a fixture with a 6mm diameter hole, with the front end protruding 4mm. This fixture with the rubber was mounted on a continuous loading scratch strength testing machine (product name "TRIBOGEAR TYPE18", manufactured by Shinto Science Co., Ltd.). Under conditions of 23±5℃ and 40±10%RH, with a load of 1.96N and a moving speed of 840mm / min, the rubber was rubbed against the functional layer side of the laminate in the following sequence: the untested portion, the tested portion, and the untested portion. The frictional force was then measured. At this time, if... Figure 2 As shown, the rubber is moved perpendicularly to the length direction of the rectangular rubber test section 32, as indicated by the arrow.

[0403] Furthermore, regarding the frictional force between the rubber test site and the rubber, the maximum value of the frictional force is calculated. Additionally, regarding the frictional force between the rubber test site and the rubber, such as... Figure 2As shown, when the point where the frictional force on the rubber reaches its maximum value in the rubber test implementation section 32 is set to 0mm, the average value of the frictional force in the rubber test non-implementation section 31 is calculated within a range of 4.2mm to 9.8mm with the above-mentioned point (0mm) as the reference.

[0404] Furthermore, regarding the ratio of frictional force before and after the rubber test, on the functional layer side of the aforementioned laminate, when the average frictional force of the part where the rubber test was not performed is set as A, and the maximum frictional force of the part where the rubber test was performed is set as B, it is calculated by the following formula.

[0405] The ratio of frictional forces = B / A

[0406] (3) Slippery properties of the rubber before and after the test

[0407] The above-described rubber test was performed on the functional layer side surface of the laminates of the embodiments and comparative examples to evaluate the slippage of the functional layer side surface of the laminates before and after the rubber test. Specifically, in the order of the untested portion, the tested portion, and the untested portion, the functional layer side surface of the laminates was rubbed with a fingertip at a moving speed of 10 cm / s at a temperature of 23±5°C and a humidity of 40±10%RH, and the slippage of the tested portion was evaluated according to the following criteria.

[0408] A: More than 7 out of 10 people cannot feel the hook.

[0409] B: 5 or 6 out of 10 people will not feel the hook.

[0410] C: 6 or 7 out of 10 people felt the hook.

[0411] D: More than 8 out of 10 people felt the hook.

[0412] (4) Steel wool test

[0413] First, a protective film with an adhesive layer on one side of a PET substrate (PET substrate thickness: 100μm to 125μm, adhesive layer thickness: 10μm to 25μm) is adhered to the substrate layer side of a 4cm × 10cm laminate. Then, the ends of the laminate are fixed to the test bench of a vibration-type friction fastness tester AB-301 manufactured by TESTERSANGYO Co., Ltd. Next, using #0000 steel wool (BONSTAR #0000 manufactured by Japan Steel Wool Co., Ltd.), the steel wool is fixed to a 2cm × 2cm clamp. The test is conducted at a temperature of 23±5℃ and a humidity of 40±10%RH, with a load of 9.8N, a reciprocating speed of 40rpm, a reciprocating distance of 40mm, and a steel wool application area of ​​4cm². 2Under these conditions, the functional layer side of the display device was rubbed back and forth 2500 times. Then, the presence or absence of damage was confirmed by transmission and reflection.

[0414]

[0415] (5) The ratio of the number of fluorine atoms to the total number of atoms of all elements before and after the rubber test.

[0416] The functional layer side surfaces of the laminates of Example 1 and Comparative Example 1 were subjected to the above-described rubber test. The composition of the functional layer side surfaces of the laminates before and after the rubber test, and the rubber surface before and after the rubber test, were analyzed by X-ray photoelectron spectroscopy (XPS). First, using an X-ray photoelectron spectrometer (AXIS-NOVA manufactured by Kratos), X-rays were irradiated along the depth direction from the sample surface under the following conditions, and X-ray photoelectron spectra were measured for C, O, F, N, Si, Ca, and Cl as the analytical elements.

[0417] Subtract the background determined by the Shirley method from the obtained spectrum, and use the relative sensitivity coefficient method to calculate the ratio of the number of atoms of each element to the total number of atoms of all elements on the sample surface from the peak area (the ratio of the number of atoms of each element (at%) when the total number of carbon, oxygen, fluorine, nitrogen, silicon, calcium and chlorine atoms is set to 100 at%). The results are shown in Tables 2 and 3.

[0418] (Measurement conditions)

[0419] Incident X-rays: Monochromated Al-Kα rays (Hv = 1486.6 eV)

[0420] • X-ray irradiation area (measurement area):

[0421] X-ray output power: 150W (15kV, 6.7mA)

[0422] • Photoelectron measurement angle: 90°±15° (set the sample normal to 0°)

[0423] • Charge neutralization conditions: Electron neutralization gun (+6V, 0.05mA), low-acceleration Ar + Ion irradiation

[0424] • Measured peaks: C1s, O1s, F1s, N1s, Si2p, Ca2p, Cl2p

[0425] [Table 2]

[0426]

[0427] [Table 3]

[0428]

[0429] Tables 2 and 3 confirm that after the rubber test, the proportion of fluorine atoms on the functional layer side of the laminate to the total number of atoms of all elements decreases, while the proportion of fluorine atoms on the rubber side to the total number of atoms of all elements increases. Therefore, by rubbing the functional layer side of the laminate with a rubber, fluorine atoms contained in the functional layer adhere to the rubber. This is believed to be because, by rubbing the functional layer side of the laminate with a rubber, the surface of the functional layer becomes negatively charged. Due to this effect, the contact surface of the rubber becomes positively charged. As a result, the electrostatic force and attraction increase, causing the strongly negatively charged fluorine to detach from the surface of the functional layer and adhere to the surface of the rubber.

[0430] Furthermore, Table 1 confirms that when the absolute value of the charge on the functional layer side of the laminate after the rubber test is within a specified range, the change in slip properties before and after the rubber test is small, and the wear resistance is excellent. This is believed to be because by ensuring that the absolute value of the charge on the functional layer side of the laminate after the rubber test is within a specified range, the detachment of fluorine from the surface of the functional layer can be suppressed, resulting in excellent wear resistance.

[0431] That is, the present invention can provide the following solutions.

[0432] [1] A laminate for a display device having a substrate layer and a fluorine-containing functional layer, wherein, after a rubber test in which a 9.8N load is applied to the surface of the laminate for the display device with a 6mm diameter rubber and rubbed back and forth 2500 times, the absolute value of the charge on the surface of the laminate for the display device having the functional layer side is 10.0nC or less.

[0433] [2] As described in [1], the ratio of the initial average value of the friction force on the rubber relative to the functional layer side surface of the initial laminate for the display device to the maximum value of the friction force on the rubber after the rubber test is 1.7 or less.

[0434] [3] The laminate for display devices as described in [1] or [2], wherein the ratio of the number of fluorine atoms on the surface of the functional layer side to the total number of atoms of all elements after the rubber test is 0.4 or more, relative to the ratio of the number of fluorine atoms on the surface of the functional layer side to the total number of atoms of all elements as determined by X-ray photoelectron spectroscopy.

[0435] [4] A laminate for a display device as described in any one of [1] to [3], wherein the functional layer contains an antistatic agent.

[0436] [5] The display device laminate as described in [4], wherein the antistatic agent is a conductive polymer.

[0437] [6] A laminate for a display device as described in any one of [1] to [5], wherein an impact-absorbing layer is provided on the side of the substrate layer opposite to the functional layer, or between the substrate layer and the functional layer.

[0438] [7] A laminate for a display device as described in any one of [1] to [6], wherein an adhesive layer for attachment is provided on the side of the substrate layer opposite to the functional layer.

[0439] [8] A laminate for a display device as described in any one of [1] to [7], wherein the distance between the outermost surface of the functional layer side of the laminate for the display device and the layer containing the antistatic agent is 10 μm or less.

[0440] [9] A laminate for a display device as described in any one of [1] to [8], wherein an anti-reflective layer is disposed on the outermost surface of the laminate for the display device on the side of the functional layer.

[0441]

[10] A display device comprising a display panel and a display device laminate disposed on the observer side of the display panel as described in any one of [1] to [9].

[0442] Explanation of reference numerals in the attached figures

[0443] 1…Laminated materials for display devices

[0444] 2…Substrate layer

[0445] 3…functional layer

[0446] 4… Hard coating

[0447] 5…Shock Absorption Layer

[0448] 6…Adhesive layer for application

[0449] 7… Interlayer adhesive layer

[0450] 20… Flexible display devices

[0451] 21… Display Panel

Claims

1. A laminate for a display device, comprising a substrate layer and a fluorine-containing functional layer, wherein, After a rubber test was conducted in which a 9.8N load was applied to the functional layer side of the laminate for the display device using a 6mm diameter rubber for 2500 reciprocating rubs, the absolute value of the charge on the functional layer side of the laminate for the display device was less than 10.0nC. The fluorine-containing functional layer is a functional layer containing a fluorine compound, which is located on the side of the functional layer opposite to the substrate layer. The fluorine compound is a fluorine compound with reactive functional groups.

2. The layered body for a display device according to claim 1, wherein The ratio of the initial average friction force of the rubber to the surface of the functional layer side of the initial laminate for the display device to the maximum value of the friction force of the rubber after the rubber test is 1.7 or less.

3. The laminate for a display device as described in claim 1, wherein, The ratio of the number of fluorine atoms on the functional layer side surface to the total number of atoms of all elements, as determined by X-ray photoelectron spectroscopy, is 0.4 or higher.

4. The laminate for a display device as claimed in claim 1, wherein, The functional layer contains an antistatic agent.

5. The laminate for a display device as described in claim 4, wherein, The antistatic agent is a conductive polymer.

6. The laminate for a display device as claimed in claim 1, wherein, An impact-absorbing layer is provided on the side of the substrate layer opposite to the functional layer, or between the substrate layer and the functional layer.

7. The laminate for a display device as claimed in claim 1, wherein, An adhesive layer for attachment is provided on the side of the substrate layer opposite to the functional layer.

8. The laminate for a display device as claimed in claim 1, wherein, The distance between the outermost surface of the functional layer side of the laminate used in the display device and the layer containing the antistatic agent is less than 10 μm.

9. The laminate for a display device as claimed in claim 1, wherein, An anti-reflective layer is disposed on the outermost surface of the functional layer side of the laminate for the display device.

10. The laminate for a display device as claimed in claim 1, wherein, In a steel wool test in which a specified load was applied to the functional layer side of the laminate for the display device by 2,500 cycles of reciprocating friction using #0000 steel wool, no scratches were found on the functional layer side of the laminate for the display device under a maximum load of 4.9 N or more.

11. A display device comprising: Display panel, and A laminate for a display device according to any one of claims 1 to 10, disposed on the observer side of the display panel.

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