Stacked body for display and display

Abstract

The present invention provides a laminate for a display device having a substrate layer and a fluorine-containing functional layer. After performing an eraser test in which a load of 9.8 N is applied to the surface of the functional layer of the laminate with an eraser of 6 mm in diameter and the laminate is rubbed back and forth 2500 times, the absolute value of the charge on the surface of the functional layer of the laminate is 10.0 nC or less.

Description

[Technical Field]

[0001] This invention relates to a laminate for a display device and a display device using the same. [Previous Technology]

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

[0003] In recent years, not only smartphones or tablets with touch functionality, but also laptops and other display devices have included touch functionality. In touch-enabled display devices, operation is performed by directly touching the surface with fingers, thus requiring durability and slip resistance.

[0004] Furthermore, portable display devices such as smartphones or tablets are often stored in, for example, clothing pockets or bags, and the surface of the display device may be rubbed by the texture of the clothing or bag, or by other items stored in the clothing pocket or bag. Therefore, portable display devices require abrasion resistance.

[0005] Recently, flexible displays such as foldable displays, rollable displays, and bendable displays have attracted attention, and laminates disposed on the surface of flexible displays are being actively developed. For example, the use of resin substrates to replace glass substrates is being studied. For example, Patent Document 1 proposes a display device window film, which comprises: 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] Because flexible displays are used or stored in, for example, a bent state, the surface of the bent portion is easily abraded. Therefore, flexible displays need to have excellent abrasion resistance in the bent portion.

[0007] It is known that, in order to improve wear resistance, for example, by reducing the coefficient of friction, a technique is known to impart low friction by coating a fluorine-based surface treatment agent or adding a fluorine-based additive. For example, Patent Document 2 discloses a surface treatment agent containing a polymer composition of fluorinated oxyalkylene groups, which can impart a coating with excellent water and oil repellency, scratch resistance, low dynamic friction, and wear resistance.

[0008] However, because the surface of the functional layer in the aforementioned laminate is rubbed, the components contained in the functional layer are wiped away, or the functional layer is worn, the performance of the functional layer deteriorates, and it is desirable to further improve the wear resistance. [Prior Art Documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2016-125063 [Patent Document 2] Japanese Patent No. 6140348 [Summary of the Invention]

[0010] [The problem that the invention aims to solve]

[0011] This invention was made in view of the above-mentioned actual situation, and its main objective is to provide a laminate for a display device with excellent wear resistance and a display device. [Technical Means for Solving the Problem]

[0012] In order to solve the above-mentioned problems, the inventors of the present invention focused on the eraser test as an abrasion test and conducted in-depth research on the abrasion resistance of laminates for display devices. Surprisingly, they discovered a new correlation between abrasion resistance and the absolute value of charge. The present invention is based on this insight.

[0013] One embodiment of the present invention provides a multilayer for a display device, which has a substrate layer and a fluorine-containing functional layer. After performing an eraser test in which a load of 9.8 N is applied to the surface of the multilayer for the display device using an eraser with a diameter of 6 mm and the multilayer is rubbed back and forth 2500 times, the absolute value of the charge on the surface of the multilayer for the display device is 10.0 nC or less.

[0014] Preferably, the ratio of the maximum value of the friction force against the eraser after the eraser test to the initial average value of the friction force against the eraser on the functional layer side surface of the initial display device laminate to the maximum value of the friction force against the eraser after the eraser test is 1.7 or less.

[0015] Furthermore, the laminate for the display device in the present invention preferably has a ratio of fluorine atoms on the surface of the functional layer to the total number of atoms of all elements after the eraser test to 0.4 or more, relative to the ratio of the number of fluorine atoms on the surface of the functional layer to the total number of atoms of all elements as measured by X-ray photoelectron spectroscopy.

[0016] Furthermore, in the present invention, the laminate for the display device preferably contains an antistatic agent in the functional layer. In this case, the antistatic agent is preferably a conductive polymer.

[0017] Furthermore, the stacked body for the display device in the present invention may 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.

[0018] Furthermore, the display device laminate of the present invention may have an adhesive layer for attachment on the side of the substrate layer opposite to the functional layer.

[0019] Another embodiment of the present invention provides a display device comprising a display panel and a laminated body for the display device disposed on the observer side of the display panel. [Effects of the Invention]

[0020] The present invention achieves the following effects: it can provide a laminate for a display device with excellent wear resistance and a display device.

Implementation Method

[0022] Hereinafter, embodiments of the present invention will be described with reference to drawings, etc. The present invention can be implemented in many different ways and is not limited to the description of the embodiments illustrated below. Furthermore, to make the explanation clearer, the drawings may sometimes schematically represent the width, thickness, shape, etc. of various parts compared to the actual form; however, this is only an example and does not limit the interpretation of the present invention. Also, in this specification and the drawings, elements that are the same as those described in the preceding figures are marked with the same symbols, and detailed descriptions may sometimes be omitted appropriately.

[0023] In this specification, when describing the arrangement of other components on a certain component, if the description is simply "on top of" or "below," unless otherwise specified, it includes the following two situations: the other component is arranged directly above or below a certain component in a manner connected to that component; and the other component is arranged above or below a certain component, intervening in another component. Furthermore, in this specification, when describing the arrangement of other components on the surface of a certain component, if the description is simply "on the side of" or "on the surface of," unless otherwise specified, it includes the following two situations: the other component is arranged directly above or below a certain component in a manner connected to that component; and the other component is arranged above or below a certain component, intervening in another component.

[0024] The inventors of this invention focused on the eraser test as a wear test and conducted in-depth research on the wear resistance of the laminate for display devices, and obtained the following insights as a result.

[0025] The inventors of this invention conducted an eraser test on the laminated body for display devices, measuring the frictional force before and after the eraser test and the amount of charge after the eraser test. The results showed that when the absolute value of the charge after the eraser test was relatively small, the change in frictional force before and after the eraser test tended to be relatively small. This revealed a correlation between abrasion resistance and the absolute value of the charge after the eraser test. Furthermore, the relationship between abrasion resistance and the absolute value of the charge after the eraser test was investigated in detail, and it was found that, in order to impart excellent abrasion resistance, it is important to set the absolute value of the charge after the eraser test to a specific value or below.

[0026] Hereinafter, the display device laminate and the display device of the present invention will be described in detail.

[0027] A. A laminate for a display device The laminate system for a display device of the present invention comprises a substrate layer and a fluorine-containing functional layer, and after performing an eraser test in which a load of 9.8 N is applied to the surface of the functional layer side of the laminate with an eraser of 6 mm in diameter and the laminate is rubbed back and forth 2500 times, the absolute value of the charge on the surface of the functional layer side of the laminate is 10.0 nC or less.

[0028] FIG1 is a schematic cross-sectional view showing an example of a multilayer for a display device according to the present invention. As shown in FIG1, the multilayer for a display device 1 has a substrate layer 2 and a functional layer 3. Furthermore, after a specific eraser test, the absolute value of the charge on the surface of the functional layer 3 side of the multilayer for a display device 1 is below a specific value.

[0029] As described above, the present invention is based on the novel insight that there is a correlation between the abrasion resistance of a laminate for a display device and the absolute value of the charge amount after an eraser test. In the present invention, by making the absolute value of the charge amount on the functional layer side surface of the laminate for a display device after an eraser test below a specific value, excellent abrasion resistance can be obtained.

[0030] The reasoning is unclear, but it is speculated as follows: It is believed that if an eraser test is performed on the surface of the laminate used in the display device, the surface of the laminate will become charged due to the friction from the eraser. Generally, the surface of the fluorine-containing layer tends to become negatively charged. Therefore, the fluorine-containing functional layer is also prone to becoming negatively charged, and the functional layer side of the laminate used in the display device becomes negatively charged due to the friction from the eraser. As a result, the contact surface between the eraser and the functional layer side of the laminate used in the display device becomes positively charged. It is believed that if the electrostatic force increases due to the eraser test, i.e., the absolute value of the charge after the eraser test is larger, the attraction will increase. Therefore, the fluorine contained in the functional layer will easily detach and adhere to the eraser. If the fluorine contained in the functional layer detaches, the wear resistance effect produced by the fluorine will decrease. On the other hand, it is believed that when the electrostatic force is relatively small even after an eraser test, i.e., when the absolute value of the charge after the eraser test is small, the attraction is small, and therefore the fluorine contained in the functional layer is less likely to detach. In this case, the wear resistance effect generated by the fluorine can be maintained. Therefore, it is believed that in this invention, by ensuring that the absolute value of the charge on the functional layer side surface of the display device laminate after the eraser test is below a certain value, the charging of the functional layer side surface of the display device laminate caused by the eraser test can be suppressed, and the detachment of fluorine caused by the eraser test as described above can be suppressed. It is anticipated that excellent wear resistance can be obtained.

[0031] Furthermore, since the friction of an eraser is similar to that of a stylus, the abrasion resistance to relatively soft materials such as styluses, fingers, clothing, or bags can be evaluated through an eraser test. In this invention, since the absolute value of the charge on the surface of the functional layer side of the display device laminate after the eraser test is below a specific value, excellent abrasion resistance to relatively soft materials such as styluses, fingers, clothing, or bags can be obtained.

[0032] Hereinafter, the various components of the display device laminate of the present invention will be described.

[0033] 1. Characteristics of the laminate for display devices In this invention, after conducting an eraser test in which a load of 9.8 N is applied to the functional layer side surface of the laminate for display devices using an eraser with a diameter of 6 mm and the surface is rubbed back and forth 2500 times, the absolute value of the charge on the functional layer side surface of the laminate for display devices is 10.0 nC or less, preferably 8 nC or less, and more preferably 6 nC or less. By keeping the absolute value of the charge within the above range, excellent wear resistance can be obtained. Furthermore, the smaller the absolute value of the charge, the better; for example, it can be 0 nC.

[0034] Here, the eraser test can be performed by the following method. That is, using an eraser with a diameter of 6 mm, insert it into a fixture with a 6 mm diameter hole, leaving 4 mm of the eraser's tip exposed. Mount the fixture with the eraser onto a vibration-type friction testing machine, and under conditions of a load of 9.8 N, a moving speed of 80 mm / s, and a moving distance of 40 mm, rub the functional layer side of the display device laminate with the eraser 2500 times. For example, a 6 mm diameter eraser manufactured by Minoan can be used as the 6 mm diameter eraser. Furthermore, for example, a vibration-type friction testing machine, such as the AB-301 vibration-type friction fastness testing machine manufactured by TESTER SANGYO, can be used.

[0035] Furthermore, the charge quantity can be measured by the following method. First, using a glass plate as a test stage, the ionizer is placed on the glass plate for 1 minute to remove static electricity. Next, a test piece is prepared by cutting a laminate of the display device into a size of 20 mm × 80 mm (including a 6 mm × 40 mm eraser test section), and the ionizer is placed on both sides of the test piece for 30 to 60 seconds to remove static electricity.

[0036] Next, the end of the test piece was fixed to a glass plate with transparent tape, and the eraser test was performed. Then, the test piece after the eraser 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.

[0037] At this time, using insulating and non-magnetic tweezers, the untested portion (end of the sample) of the eraser is grasped, and the test piece after the eraser test is lifted. After lifting the test piece, the charge is measured without contact with other fixed surfaces. The charge measurement is performed within 3 minutes after the eraser test. The charge measurement area is set to the entire surface of the sample.

[0038] As a Faraday cage, for example, the Faraday cage "KQ-1400" manufactured by Kasuga Electric Co., Ltd. can be used. Also, as an ionizer, for example, the fan-type ionizer "KD-750B" manufactured by Kasuga Electric Co., Ltd. can be used. Also, as tweezers, for example, the ESD (static discharge) tweezers "P-643-S" manufactured by KENIS Co., Ltd. can be used.

[0039] Methods for adjusting the absolute value of the charge on the surface of the functional layer of the laminate for display devices after the eraser test include, for example, adjusting the surface hardness of the functional layer, adjusting the thickness of the functional layer, adjusting the concentration of fluorine 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, and adjusting the drying temperature during the formation of the functional layer.

[0040] For example, if the surface hardness of the functional layer increases, the absolute value of the aforementioned charge tends to decrease. Also, for example, 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. Also, for example, if the concentration of fluorine on the surface of 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 concentration of fluorine on the surface of 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.

[0041] Furthermore, for example, if the content of the antistatic agent increases, the absolute value of the charge tends to decrease. However, if the content of the antistatic agent becomes excessive, the surface hardness of the functional layer tends to decrease, and the absolute value of the charge tends to increase. On the other hand, if the content of the antistatic agent decreases, the surface hardness of the functional layer tends to increase, and the absolute value of the charge tends to decrease.

[0042] Furthermore, for example, if the distance between the surface undergoing the eraser test and the layer containing the antistatic agent becomes closer, the absolute value of the charge tends to decrease; on the other hand, if the distance between the surface undergoing the eraser test and the layer containing the antistatic agent becomes farther, the absolute value of the charge tends to increase.

[0043] In this invention, the distance between the surface where the eraser test is performed and the layer containing the antistatic agent is preferably 10 μm or less, more preferably 6 μm or less, and even more preferably 4 μm or less.

[0044] Here, the "distance between the surface where the eraser test is performed and the layer containing the antistatic agent" refers to the following distance.

[0045] That is, the "surface on which the eraser test is performed" refers to the outermost surface of the aforementioned functional layer in the laminate for the display device. Furthermore, the "layer containing antistatic agent" refers to the first layer containing antistatic agent when viewed from the outermost surface towards the substrate layer. In other words, if the outermost layer contains antistatic agent, then the outermost layer is a layer containing antistatic agent; if the outermost layer does not contain antistatic agent, but the next layer does, then the next layer is a "layer containing antistatic agent".

[0046] The term "distance between the surface where the eraser 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".

[0047] Furthermore, for example, if the drying temperature during the formation of the functional layer is lower, the absolute value of the above-mentioned charge tends to be smaller. On the other hand, if the drying temperature during the formation of the functional layer is higher, the antistatic agent is not easily transferred to the surface of the functional layer, and the absolute value of the above-mentioned charge tends to be larger.

[0048] Furthermore, in this invention, when conducting a steel wool test—that is, applying a specific load to the functional layer side of a laminate for a display device using #0000 steel wool and rubbing it back and forth 2500 times—the maximum load at which scratches are not detected on the functional layer side of the laminate for a display device is preferably 4.9 N or more, more preferably 9.8 N or more, and even more preferably 14.7 N or more. By keeping the maximum load within the aforementioned range, the hardness of the functional layer side of the laminate for a display device can be increased, thereby improving scratch resistance.

[0049] Here, the steel wool test can be performed by the following method. That is, using #0000 steel wool, the steel wool is fixed to a 2 cm × 2 cm clamp, and rubbed against the functional layer side of the laminate for the display device 2500 times at a reciprocating speed of 40 rpm and a reciprocating distance of 40 mm. The #0000 steel wool can be BONSTAR #0000 manufactured by NIPPON STEEL WOOL. Furthermore, the testing machine can be, for example, the vibration-type friction fastness tester AB-301 manufactured by TESTER SANGYO. Furthermore, the steel wool test is performed, for example, in the following manner: after a protective film with an adhesive layer on one side of a PET substrate is bonded to the substrate layer side of a 4 cm × 10 cm display device laminate, it is placed on the testing machine with the functional layer side of the display device laminate facing up, and the ends of the display device laminate are fixed with transparent tape (cellophane tape).

[0050] Furthermore, the abrasion resistance of relatively hard materials, such as those in clothing pockets or bags, can be evaluated by using a steel wool test.

[0051] 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 placing the pencil hardness within the above range, the hardness of the functional layer side surface of the laminate for display devices can be increased, thereby improving scratch resistance.

[0052] Here, the pencil hardness is determined using the pencil hardness test specified in JIS K5600-5-4 (1999). Specifically, it can be performed by using a test pencil specified in JIS-S-6006 to conduct the pencil hardness test specified in JIS K5600-5-4 (1999) on the functional layer side of the laminate for display devices, and evaluating the highest pencil hardness that will not cause scratches. The test conditions can be set as follows: angle 45°, load 1000 g, speed 0.5 mm / s to 1 mm / s, and temperature 23±2℃. As for the pencil hardness testing machine, for example, a pencil scratch coating hardness testing machine manufactured by Toyo Seiki Co., Ltd. can be used.

[0053] Furthermore, in this invention, the average value of the frictional force against the eraser on the functional layer side surface of the laminate for the display device is preferably 0.98 N or more and 9.80 N or less, more preferably 1.96 N or more and 8.80 N or less, and even more preferably 2.45 N or more and 7.80 N or less. If the initial average value of the frictional force against the eraser is within the above range, the wear resistance can be improved.

[0054] Furthermore, in this invention, after conducting an eraser test in which a load of 9.8 N is applied to the functional layer side of the laminate for the display device using an eraser with a diameter of 6 mm and the two sides are rubbed back and forth 2500 times, the maximum value of the frictional force on the functional layer side of the laminate for the display device against the eraser is preferably, for example, 0.98 N or more and 9.80 N or less, more preferably 1.96 N or more and 8.80 N or less, and even more preferably 2.45 N or more and 7.80 N or less. By ensuring that the frictional force on the eraser after the eraser test is within the above-mentioned range, excellent wear resistance can be obtained, and excellent antistatic properties can be maintained.

[0055] Furthermore, the ratio of the maximum value of the frictional force against the eraser after an eraser test on the functional layer side of the laminated body for the display device to the initial average value of the frictional force against the eraser is preferably 1.7 or less, more preferably 1.5 or less, and even more preferably 1.3 or less. By keeping the ratio of the frictional force against the eraser within the above range, wear resistance can be improved. Furthermore, the smaller the ratio of the frictional force against the eraser, the better; for example, it can be 1.00.

[0056] Regarding the aforementioned ratio of frictional force to the eraser, when the average value of the frictional force to the eraser on the functional layer side of the display device laminate before the eraser test is set as A, and the maximum value of the frictional force to the eraser on the functional layer side of the display device laminate after the eraser test is set as B, it is calculated according to the following formula: Ratio of frictional force = B / A

[0057] Here, regarding the frictional force of the eraser, an eraser with a diameter of 6 mm can be used. The eraser is inserted into a fixture with a 6 mm diameter hole, with 4 mm of its tip protruding. The fixture with the eraser is mounted on a friction testing machine, and the friction is measured by rubbing the functional layer side surface of the display device laminate with the eraser at a load of 1.96 N and a moving speed of 840 mm / min. For example, a 6 mm diameter eraser manufactured by Minoan Corporation can be used as the 6 mm diameter eraser. Furthermore, a friction testing machine such as the TRIBOGEAR TYPE18 manufactured by Shin-Tung Science & Technology Co., Ltd. can be used. Specifically, as shown in FIG2, firstly, the above-mentioned eraser test is performed on a portion of the functional layer side surface 30 of the display device laminate 1, forming a rectangular eraser test implementation part 32. Next, using an eraser, as indicated by the arrow, the functional layer side surface 30 of the display device laminate 1 is rubbed in the order of eraser test non-implementation part 31, eraser test implementation part 32, and eraser test non-implementation part 31, and the friction force is measured. At this time, the eraser is moved perpendicularly to the long side direction of the rectangular eraser test implementation part 32 as indicated by the arrow. The average value of the friction force of the eraser test non-implementation part on the eraser can be taken as the initial average value of the friction force on the eraser, and the maximum value of the friction force of the eraser test implementation part on the eraser can be taken as the maximum value of the friction force on the eraser after the eraser test. Furthermore, as shown in FIG2, the initial average value of the friction force on the eraser is set to the following value, that is, when the point where the friction force of the eraser test implementation part 32 on the eraser reaches the maximum value is set to 0 mm, the average value of the friction force in the eraser test non-implementation part 31 in the range of 4.2 mm to 9.8 mm with the above point (0 mm) as the reference.

[0058] Furthermore, in this invention, the ratio of the number of fluorine atoms on the functional layer side of the laminate for a display device, as measured by X-ray photoelectron spectroscopy, to the total number of atoms of all elements is preferably 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-mentioned range, the wear resistance can be improved.

[0059] Furthermore, in this invention, after performing an eraser test by applying a 9.8 N load to the functional layer side of the display device laminate using an eraser with a diameter of 6 mm and rubbing it back and forth 2500 times, the ratio of the number of fluorine atoms on the functional layer side of the display device laminate to the total number of atoms of all elements, as measured 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 eraser test is within the above range, the fluorine contained in the functional layer can be suppressed from detaching due to the eraser test, thereby improving wear resistance.

[0060] Furthermore, relative to the ratio of the number of fluorine atoms on the functional layer side of the initial display device laminate as measured 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 eraser test to the total number of atoms of all elements is preferably 0.4 or higher, more preferably 0.6 or higher, and even more preferably 0.7 or higher. By keeping the ratio of the number of fluorine atoms within the above range, abrasion resistance can be improved. Furthermore, the higher the ratio of the number of fluorine atoms, the better; for example, it can be 1.0.

[0061] Regarding the ratio of the number of fluorine atoms mentioned above, when the ratio of the number of fluorine atoms on the functional layer side of the initial display device laminate before the eraser test to the total number of atoms of all elements is set as C, and the ratio of the number of fluorine atoms on the functional layer side of the display device laminate after the eraser test to the total number of atoms of all elements is set as D, the ratio of the number of fluorine atoms is calculated according to the following formula: Ratio of the number of fluorine atoms = D / C

[0062] Furthermore, in this invention, the ratio of the number of fluorine atoms on the surface of the eraser to the total number of atoms of all elements, as measured by X-ray photoelectron spectroscopy, is preferably below the detection limit, for example.

[0063] Furthermore, in this invention, after conducting an eraser test by applying a 9.8 N load to the functional layer side of the display device laminate using an eraser with a diameter of 6 mm and rubbing it back and forth 2500 times, the ratio of the number of fluorine atoms on the surface of the eraser in contact with the functional layer side of the display device laminate, as measured by X-ray photoelectron spectroscopy, to the total number of atoms of all elements, 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 eraser after the eraser test is within the above range, it is possible to suppress the fluorine contained in the functional layer from detaching and adhering to the eraser due to the eraser test, thereby improving wear resistance.

[0064] Here, the ratio of the number 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 measured by X-ray photoelectron spectroscopy (XPS). Specifically, it refers to the ratio (at%) of the number of fluorine atoms when the total number of carbon atoms, oxygen atoms, fluorine atoms, nitrogen atoms, silicon atoms, calcium atoms, and chlorine atoms is set to 100 at%.

[0065] 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 following these steps: First, using an X-ray photoelectron spectrometer, X-rays are irradiated from the sample surface toward the depth direction under the following conditions, and the X-ray photoelectron spectrum is measured. For example, an X-ray photoelectron spectrometer manufactured by Kratos Corporation, AXIS-NOVA, can be used. 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 elements to be analyzed. The background value determined by the Shirley method is subtracted from the obtained spectrum, and the ratio of fluorine atoms (at%) is determined using the relative sensitivity coefficient method based on the peak area, with the total number of carbon, oxygen, fluorine, nitrogen, silicon, calcium, and chlorine atoms set to 100 at%.

[0066] <Measurement Conditions> ・Incident X-rays: Monochromated Al-Kα rays (Hv=1486.6 eV) ・X-ray irradiation area (measurement area): 110 μm ・X-ray output: 150 W (15 kV, 6.7 mA) ・Photoelectron receiving angle: 90°±15° (with the sample normal set to 0°) ・Charge neutralization conditions: Electron neutralization gun (+6 V, 0.05 mA), low-acceleration Ar+ ion irradiation ・Measurement peaks: C1s, O1s, F1s, N1s, Si2p, Ca2p, Cl2p

[0067] Furthermore, when measuring the ratio of the number 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 the number of fluorine atoms on the functional layer side of the display device laminate to the total number of atoms of all elements after the eraser test, for example, as described above, an eraser test implementation unit 32 as shown in FIG2 can be formed, using the ratio of the number of fluorine atoms on the eraser test non-implementation 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 using the ratio of the number of fluorine atoms on the eraser test implementation 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 eraser test.

[0068] 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. In this way, by making the total light transmittance higher, a laminate for display devices with good transparency can be manufactured.

[0069] 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 Murakami Color Technology Research Institute.

[0070] 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. In this way, by making the haze lower, a laminate for display devices with good transparency can be manufactured.

[0071] Here, the haze of the display device laminate can be measured according to JIS K-7136, for example, by using the HM150 haze meter manufactured by Murakami Color Technology Research Institute.

[0072] 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.

[0073] The dynamic bending test is conducted as follows. First, a display device laminate of size 20 mm × 100 mm is prepared. Then, in the dynamic bending test, as shown in FIG3(a), the short side 1C of the display device laminate 1 and the short side 1D opposite to the short side 1C are fixed by parallel fixing parts 51. Also, as shown in FIG3(a), the fixing parts 51 can slide along the horizontal direction. Next, as shown in FIG3(b), the fixing parts 51 are moved in a manner that brings them closer together, thereby causing the display device laminate 1 to fold and deform. Then, as shown in FIG3(c), the fixing parts 51 are moved to a position where the interval d between the two opposite short sides 1C and 1D fixed by the fixing parts 51 of the display device laminate 1 is a specific value. Then, the fixing parts 51 are moved in the opposite direction to eliminate the deformation of the display device laminate 1. As shown in Figures 3(a) to (c), the display device laminate 1 can be folded 180° by moving the fixing part 51. Furthermore, a dynamic bending test can be performed so that the bent part 1E of the display device laminate 1 does not protrude from the lower end of the fixing part 51, and the interval between the fixing parts 51 when they are closest can be controlled to set the interval d between the two opposing short sides 1C and 1D of the display device laminate 1 to a specific value. For example, when the interval d between the short sides 1C and 1D is 30 mm, the outer diameter of the bent part 1E is considered to be 30 mm.

[0074] In the laminate for display devices, it is preferable that no cracking or breakage occurs when a dynamic bending test is repeated 200,000 times with the interval d between the opposing short sides 1C and 1D of the laminate 1 for display devices being 30 mm. More preferably, no cracking or breakage occurs when the dynamic bending test is repeated 500,000 times. Preferably, no cracking or breakage occurs when a dynamic bending test is repeated 200,000 times with the interval d between the opposing short sides 1C and 1D of the laminate 1 for display devices being 20 mm. Even more preferably, no cracking or breakage occurs when a dynamic bending test is repeated 200,000 times with the interval d between the opposing short sides 1C and 1D of the laminate 1 for display devices being 10 mm.

[0075] In the dynamic bending test, the display device laminate can be folded with the functional layer on the outside or with the functional layer on the inside, but preferably, the display device laminate does not crack or break in either case.

[0076] 2. Functional Layer The functional layer in this invention is disposed on one side of the substrate layer and contains fluorine. By containing fluorine, the functional layer imparts abrasion resistance and stain resistance to the laminate for the display device.

[0077] As a functional layer, there are no particular limitations, as long as it contains fluorine. For example, the functional layer may contain fluorinated compounds and resins, or it may contain fluorinated resins.

[0078] When the functional layer contains fluorinated compounds and resins, the fluorinated compound may be, for example, one known as a fluorinated antifouling agent, fluorinated leveling agent, or fluorinated surfactant. Examples of fluorinated compounds include organofluorine compounds, and more specifically, perfluorinated compounds. Examples of perfluorinated compounds include those having a perfluoropolyether group, a perfluoroalkyl group, or a perfluoroalkyl group. The perfluoroalkyl group and perfluoroalkyl group may be linear or branched. A single fluorinated compound may be used, or two or more may be used in combination.

[0079] Furthermore, the fluorine compound is preferably combined with the resin component. By combining the fluorine compound with the resin component, the leaching of the fluorine compound can be inhibited, and the abrasion resistance and stain resistance can be maintained for a long time. In addition, the abrasion resistance or stain resistance can be easily maintained after the eraser test.

[0080] As a fluorinated compound, it is preferable to use a fluorinated compound having reactive functional groups, since it is better to combine with the resin component. That is, the functional layer is preferably a cured resin composition containing: a fluorinated compound having reactive functional groups and a polymerizable compound described later. Examples of reactive functional groups include: (meth)acrylic, vinyl, allyl and other vinyl unsaturated groups, or epoxy, oxetanyl, etc.

[0081] 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.

[0082] Furthermore, the fluorine compound may contain silicon. That is, the functional layer may contain both fluorine and silicon. Examples of silicon-containing fluorine compounds include fluorine compounds with siloxane bonds within their molecules. By using fluorine compounds with siloxane bonds, slip properties can be improved, and scratch resistance can be increased. In addition, slip properties are improved when touched with a finger or stylus, thus improving the tactile feel.

[0083] The fluorine compound is preferably a fluorine compound having a reactive functional group, or a fluorine compound containing a reactive functional group and silicon.

[0084] Examples of fluorinated compounds having reactive functional groups include: fluorinated monomers having ethylene-unsaturated bonds; fluorinated polymers or oligomers with fluoropyridine groups in the main chain; and fluorinated polymers or oligomers with fluoropyridine groups or fluoroalkyl groups in the main chain and side chains. For example, Japanese Patent Application Publication No. 2017-19247 may be consulted regarding fluorinated compounds having reactive functional groups.

[0085] Examples of fluorinated compounds containing reactive functional groups and silicon include: polysiloxane copolymers containing polysiloxane obtained by reacting an organic polysiloxane having reactive functional groups in its molecule with the aforementioned fluorinated compounds having reactive functional groups.

[0086] Furthermore, as a fluorinated compound containing reactive functional groups and silicon, it is also preferred to use a fluorinated compound having reactive functional groups and perfluoropolyether groups, wherein a fluorinated compound containing silane units having reactive functional groups and silane units having perfluoropolyether groups is more preferred. For example, International Publication No. 2012 / 157682 may be consulted regarding such fluorinated compounds.

[0087] In the functional layer, the fluorinated compound may be present uniformly or biased on the side of the functional layer opposite to the substrate layer. Preferably, the fluorinated compound is biased on the side of the functional layer opposite to the substrate layer. Sufficient abrasion resistance or stain resistance can be obtained with a small amount of addition, and the reduction of surface hardness of the functional layer can be suppressed.

[0088] As a method for dispersing fluorinated compounds 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 listed: When forming the functional layer, a resin composition for the functional layer is coated onto the substrate layer. Before drying and hardening, the coating is heated to reduce the viscosity of the resin component contained in the coating, thereby increasing its fluidity, thus dispersing the fluorinated compounds 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 heating during drying, and then the coating is hardened, thereby dispersing the fluorinated compounds on the side of the functional layer opposite to the substrate layer. Furthermore, for example, when the functional layer is multilayered, the fluorinated compounds can be dispersed on the side of the functional layer opposite to the substrate layer by containing fluorinated compounds in the layers of the multilayer functional layer located on the side opposite to the substrate layer.

[0089] The content of the fluorine compound is not particularly limited, as long as it is an amount 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 content of the fluorine compound is too low, it may not be able to impart sufficient wear resistance or stain resistance to the functional layer. Furthermore, if the content of the fluorine compound is too high, it may lead to a decrease in the surface hardness of the functional layer and a decrease in wear resistance.

[0090] Furthermore, when the functional layer contains fluorinated compounds and resins, the resin may be, for example, a cured polymeric compound. The cured polymeric compound can be obtained by using a polymerization initiator as needed and carrying out a polymerization reaction of the polymeric compound using known methods.

[0091] The polymerizable compound is one having at least one polymerizable functional group within its molecule. For example, at least one of free radical polymerizable compounds and cationic polymerizable compounds may be used as the polymerizable compound.

[0092] The term "free radical polymerizable compound" refers to a compound possessing a free radical polymerizable group. There is no particular limitation on the free radical polymerizable group possessed by a free radical polymerizable compound; it only needs to be a functional group capable of undergoing a free radical polymerization reaction. Examples include groups containing carbon-carbon unsaturated double bonds, specifically vinyl and (meth)acrylic groups. Furthermore, when a free radical polymerizable compound possesses two or more free radical polymerizable groups, these free radical polymerizable groups may be the same or different.

[0093] Regarding the number of free radical polymerizable groups in one molecule of the free radical polymerizable compound, in terms of increasing the surface hardness and improving the scratch resistance of the functional layer, it is preferably two or more, and more preferably three or more.

[0094] As a free radical polymerizable compound, in terms of reactivity, compounds having (meth)acrylic groups are preferred. For example, polyfunctional (meth)acrylate monomers and oligomers with molecular weights of hundreds to thousands, including those called amine methacrylates, polyester methacrylates, epoxy methacrylates, melamine methacrylates, polyfluoroalkyl methacrylates, and polysiloxane methacrylates, are preferred. Also preferred are polyfunctional (meth)acrylate polymers having two or more (meth)acrylic groups on their side chains. Among these, polyfunctional (meth)acrylate monomers having two or more (meth)acrylic groups per molecule are preferred. By using a hardened compound containing polyfunctional (meth)acrylate monomers in the functional layer, the surface hardness of the functional layer can be increased, thereby improving scratch resistance. Furthermore, it can also improve adhesion. Additionally, it is preferable to use polyfunctional (meth)acrylate oligomers or polymers having two or more (meth)acrylic groups per molecule. By incorporating a hardened product containing polyfunctional (meth)acrylate oligomers or polymers into the functional layer, the surface hardness of the functional layer can be increased, thereby improving scratch resistance. Furthermore, it can also improve flexural strength and adhesion.

[0095] Furthermore, in this specification, the term (meth)acrylic acid means acrylonitrile and methacrylic acid, and the term (meth)acrylate means acrylate and methacrylate.

[0096] Specific examples of polyfunctional (meth)acrylate monomers include those described in Japanese Patent Application Publication No. 2019-132930. Among these, those having 3 to 6 (meth)acrylic groups per molecule are preferred in terms of higher reactivity, increased surface hardness of the functional layer, and improved scratch resistance. Preferred polyfunctional (meth)acrylate monomers include neopentyl terephthalate triacrylate (PETA), dinepentyl terephthalate hexaacrylate (DPHA), neopentyl terephthalate tetraacrylate (PETTA), dinepentyl terephthalate pentaacrylate (DPPA), trimethylolpropane tri(meth)acrylate, trinepentyl terephthalate octa(meth)acrylate, and tetranepentyl terephthalate deca(meth)acrylate. At least one selected from neopentyl terephthalate tri(meth)acrylate, dinepentyl terephthalate penta(meth)acrylate, and dinepentyl terephthalate hexaacrylate is particularly preferred.

[0097] Furthermore, when using free radical polymerizable compounds, the presence of flexible groups within the molecular structure can reduce scratch resistance. Therefore, to suppress the reduction in scratch resistance caused by the flexible components (soft segments), it is preferable to use free radical polymerizable compounds whose molecular structure does not contain flexible groups. Specifically, it is preferable to use free radical polymerizable compounds that have not been modified with EO or PO. By using such free radical polymerizable compounds, the number of crosslinking points can be increased, thereby improving scratch resistance.

[0098] To adjust hardness or viscosity, improve adhesion, etc., the functional layer may contain a monofunctional (meth)acrylate monomer as a free radical polymerizable compound. Specific examples of monofunctional (meth)acrylate monomers may be cited, for example, those described in Japanese Patent Application Publication No. 2019-132930.

[0099] The term "cationic polymerizable compound" refers to a compound having a cationic polymerizable group. There is no particular limitation on the cationic polymerizable group possessed by a cationic polymerizable compound; it only needs to be a functional group capable of undergoing a cationic polymerization reaction. Examples include epoxy groups, oxetyl groups, and vinyl ether groups. Furthermore, when a cationic polymerizable compound has two or more cationic polymerizable groups, these cationic polymerizable groups may be the same or different.

[0100] Regarding the number of cationic polymeric groups in one molecule of the cationic polymeric compound, in terms of increasing the surface hardness and improving the scratch resistance of the functional layer, it is preferably two or more, and more preferably three or more.

[0101] Furthermore, as a cationic polymerizable compound, it is preferably a compound having at least one of epoxy group and oxetyl group as a cationic polymerizable group, and more preferably a compound having at least one of two or more epoxy group and oxetyl group in one molecule. Cyclic ether groups such as epoxy group and oxetyl group are preferred in terms of less shrinkage accompanying the polymerization reaction. Furthermore, compounds having epoxy group in cyclic ether groups have the following advantages: it is easy to obtain compounds with various structures, it does not adversely affect the durability of the obtained functional layer, and it is easy to control compatibility with free radical polymerizable compounds. Furthermore, oxetyl group in cyclic ether groups has the following advantages: it has a higher degree of polymerization and lower toxicity compared to epoxy group; when the obtained functional layer is combined with a compound having epoxy group, it accelerates the formation rate of the network structure obtained by the cationic polymerizable compound in the coating film; and in areas where it is mixed with free radical polymerizable compounds, it also forms an independent network structure without leaving unreacted monomers in the film.

[0102] Examples of cationic polymerizable compounds having epoxy groups include: polyoxypropylene ethers of polyols having alicyclic rings, or alicyclic epoxy resins obtained by epoxidation of compounds containing cyclohexene rings or cyclopentene rings with appropriate oxidants such as hydrogen peroxide or peracid; alicyclic epoxy resins such as polyoxypropylene ethers of aliphatic polyols or their epoxy alkane adducts, polyoxypropylene esters of aliphatic long-chain polyacids, and homopolymers and copolymers of (meth)acrylate; epoxy propylene ethers manufactured by reacting bisphenols such as bisphenol A, bisphenol F, or hydrogenated bisphenol A, or their epoxy alkane adducts, caprolactone adducts, etc., with epichlorohydrin; and epoxy propylene ether type epoxy resins derived from bisphenols, such as phenolic varnish epoxy resins.

[0103] Specific examples of alicyclic epoxy resins, epoxypropyl ether type epoxy resins, and cationic polymerizable compounds having oxocyclic butyl groups may be cited, for example, those described in Japanese Patent Application Publication No. 2018-104682.

[0104] The functional layer may contain a polymerization initiator as needed. As the polymerization initiator, a free radical polymerization initiator, a cationic polymerization initiator, or a combination of free radical and cationic polymerization initiators may be appropriately selected. These polymerization initiators decompose by at least one of light irradiation and heating to generate free radicals or cations for free radical polymerization and cationic polymerization. Furthermore, there are also cases where the polymerization initiator completely decomposes and does not remain in the functional layer.

[0105] Furthermore, when the functional layer contains a fluoropolymer, a cured fluoropolymer can be cited as an example. The cured fluoropolymer can be obtained by using a polymerization initiator as needed and carrying out a polymerization reaction of the fluoropolymer using a known method.

[0106] A fluorinated polymerizable compound is one having at least one polymerizable functional group within its molecule. For example, at least one of free radical polymerizable compounds and cationic polymerizable compounds may be used as a fluorinated polymerizable compound. Furthermore, for example, any one of fluorinated monomers, oligomers, and polymers may be used as a fluorinated polymerizable compound.

[0107] Furthermore, when the functional layer contains a fluorinated resin, a fluorine-free polymeric compound may be used in addition to a fluorinated polymeric compound. That is, the functional layer may contain a cured resin composition containing both a fluorinated polymeric compound and a fluorine-free polymeric compound. The fluorine-free polymeric compound may be the same as the polymeric compound used when the functional layer contains a fluorinated compound and a resin.

[0108] Furthermore, the functional layer preferably contains an antistatic agent. This imparts antistatic properties to the laminate for display devices. Also, by adjusting the content of the antistatic agent, the absolute value of the charge on the surface of the functional layer of the laminate for display devices after an eraser test can be adjusted to a specific range.

[0109] As an antistatic agent, examples include: ionically conductive antistatic agents, electronically conductive antistatic agents, etc. An antistatic agent can be used alone or in combination of two or more.

[0110] As an ion-conducting antistatic agent, either a low-molecular-weight antistatic agent or a high-molecular-weight antistatic agent can be used. The high-molecular-weight antistatic agent is, for example, an ion-conducting antistatic agent that has been polymerized by increasing its molecular weight; it is formed by introducing functional groups that impart conductivity to the polymer. Examples of ion-conducting antistatic agents include: cationic antistatic agents such as quaternary ammonium salts and pyridium salts; anionic antistatic agents such as alkali metal salts such as lithium salts, sodium salts, and potassium salts, as well as sulfonic acid, phosphoric acid, and carboxylic acid 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 or lithium salts are preferred in terms of exhibiting excellent compatibility with resins.

[0111] 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. Furthermore, antistatic agents formed by combining dopants with conductive polymers such as polyacetylene and polythiophene, or antistatic agents that contain conductive particles in the aforementioned conductive polymers, can also be used. From the viewpoint of maintaining antistatic properties, conductive polymers are preferred.

[0112] Specifically, examples of the aforementioned conductive polymers include: polyacetylene, polyaniline, polythiophene, polypyrrole, polyphenylene sulfide, poly(1,6-heptadiyne), polydiphenylene (poly-p-phenylene), poly-p-phenylene sulfide, polyphenylacetylene, poly(2,5-epithiophene), and derivatives thereof. Preferably, examples include polythiophene-based conductive polymers such as 3,4-ethylenedioxythiophene (PEDOT). By using the aforementioned conductive polymers as antistatic agents, antistatic properties can be maintained for a long period.

[0113] Examples of metals constituting the above-mentioned metal microparticles include single metals such as Au, Ag, Cu, Al, Fe, Ni, Pd, and Pt, or alloys of such metals.

[0114] The metal oxide constituting the above-mentioned 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), zinc oxide (ZnO), etc. Among these, from the viewpoint of exhibiting excellent antistatic properties, antimony-doped tin oxide (ATO) is preferred. Furthermore, among ATO, chain-like ATO consisting of a plurality of ATO particles linked together is preferred.

[0115] Among the above-mentioned antistatic agents, polymeric antistatic agents and conductive polymers are preferred, and conductive polymers are even more preferred. Even in small amounts, polymeric antistatic agents and conductive polymers can impart antistatic properties and maintain surface hardness or optical properties.

[0116] Furthermore, when the functional layer contains an antistatic agent and the functional layer is multilayered as described below, it is sufficient that at least one of the multilayer functional layers contains an antistatic agent. In this case, any layer of the multilayer functional layer may contain an antistatic agent, wherein, preferably, the layer located near the side opposite to the substrate layer contains the antistatic agent, and more preferably, the layer located on the side opposite to the substrate layer, that is, the outermost layer of the multilayer functional layer contains the antistatic agent. The reason for this is that the closer the surface where the eraser test is performed is to the layer containing the antistatic agent, the easier it is to adjust the absolute value of the charge on the functional layer side of the display device laminate after the eraser test to a specific range.

[0117] The content of the antistatic agent is not particularly limited, as long as it is sufficient to obtain a functional layer that satisfies the absolute value of the aforementioned charge amount. It can be appropriately selected based on the type of antistatic agent, etc. For example, the content of the antistatic agent relative to 100 parts by mass of the resin component 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, it may cause the surface hardness of the functional layer to decrease, reducing its wear resistance. Moreover, when the functional layer contains an antistatic agent and the functional layer is multilayered as described below, it is preferable that the content of the antistatic agent in the layers containing the antistatic agent in the multilayered functional layers is within the aforementioned range.

[0118] The functional layer may contain additives such as inorganic particles, organic particles, ultraviolet absorbers, antioxidants, light stabilizers, anti-glare agents, leveling agents, surfactants, slip agents, various sensitizers, flame retardants, adhesives, polymerization inhibitors, and surface modifiers.

[0119] The functional layer can be a single layer or multiple layers.

[0120] The thickness of the functional layer is not particularly limited, as long as it is a thickness that satisfies the above-mentioned 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 thickness of the functional layer is too thin, the surface hardness of the functional layer may decrease, and the wear resistance may decrease. Furthermore, if the thickness of the functional layer is too thick, there is a risk of damage to flexibility. Moreover, as mentioned above, by adjusting the thickness of the functional layer, the absolute value of the charge on the surface of the functional layer of the display device laminate after the eraser test can be adjusted to a specific 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 multilayer functional layer is within the above-mentioned range.

[0121] Here, the thickness of the functional layer can be set as the average thickness of any 10 locations measured from a cross-section of the display device laminate observed by a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM). Furthermore, the method for measuring the thickness of other layers in the display device laminate can also be set as the same method.

[0122] The functional layer can be disposed on one side of the substrate layer, wherein, preferably, in the laminate for display device, the functional layer is disposed on the outermost surface.

[0123] As a method for forming a functional layer, for example, a method of coating a resin composition for a functional layer onto a substrate layer and then curing it.

[0124] 3. Substrate layer The substrate layer in this invention is a transparent component that supports the above-mentioned functional layer.

[0125] As a substrate layer, there are no particular limitations, as long as it is transparent, for example: resin substrate, glass substrate, etc.

[0126] (1) The resin substrate is not particularly limited as to the resin constituting the resin substrate, as long as a transparent resin substrate can be obtained. Examples include: polyimide resin, polyamide resin, polyester resin, etc. Examples of polyimide resins include: polyimide, polyamide-imide, polyether-imide, polyester-imide, etc. Examples of polyester resins include: polyethylene terephthalate, polyethylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, etc. Among these, in terms of having bending resistance, excellent hardness and transparency, polyimide resin, polyamide resin, or a mixture thereof is preferred, and polyimide resin is more preferred.

[0127] There are no particular limitations on the polyimide resin, as long as a transparent resin substrate can be obtained. Among the above, polyimide and polyamide-imide are preferred.

[0128] (a) Polyimide Polyimide is obtained by reacting a tetracarboxylic acid component with a diamine component. There are no particular limitations on polyimide, as long as it has transparency and rigidity. For example, in terms 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).

[0129]

[0130] In the above general formula (1), R1 represents a tetravalent group as a tetracarboxylic acid residue, and R2 represents at least one divalent group selected from the group consisting of trans-cyclohexanediamine residue, trans-1,4-dimethylenecyclohexanediamine residue, 4,4'-diaminodiphenyl sulfone residue, 3,4'-diaminodiphenyl sulfone residue, and the divalent group represented by the following general formula (2). n represents the number of repeating units, which is 1 or more.

[0131]

[0132] In the above general formula (2), R3 and R4 independently represent hydrogen atoms, alkyl groups, or perfluoroalkyl groups, respectively.

[0133]

[0134] In the above general formula (3), R5 represents at least one tetravalent group selected from the group consisting of cyclohexanetetracarboxylic acid residue, cyclopentanetetracarboxylic acid residue, dicyclohexane-3,4,3',4'-tetracarboxylic acid residue, and 4,4'-(hexafluoroisopropylidene)phthalic acid residue, and R6 represents a divalent group as a diamine residue. n' represents the number of repeating units, which is 1 or more.

[0135] Furthermore, the term "tetracarboxylic acid residue" refers to a residue obtained by removing four carboxyl groups from a tetracarboxylic acid, indicating the same structure as the residue obtained by removing the acid dianhydride structure from a tetracarboxylic acid dianhydride. Also, the term "diamine residue" refers to a residue obtained by removing two amino groups from a diamine.

[0136] In the above general formula (1), R1 is a tetracarboxylic acid residue, which can be a residue obtained by removing the acid dianhydride structure from a tetracarboxylic dianhydride. For example, the tetracarboxylic dianhydride described in International Publication No. 2018 / 070523 can be cited as an example. As R1 in the above general formula (1), in terms of improving transparency and rigidity, it is preferably composed of 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'-diphenyltetracarboxylic acid residue, 4,4'-oxophthalic acid residue, cyclohexanetetracarboxylic acid residue, and cyclopentanetetracarboxylic acid residue, and more preferably, it is composed of 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'-diphenyltetracarboxylic acid residue.

[0137] In R1, it is preferable that the total amount of such preferred residues is 50 mol% or more, more preferably that the total amount of such preferred residues is 70 mol% or more, and even more preferably that the total amount of such preferred residues is 90 mol% or more.

[0138] Furthermore, as R1, it is also preferable to use a mixture of the following tetracarboxylic acid residue group (Group A) and the following tetracarboxylic acid residue group (Group B), wherein the aforementioned tetracarboxylic acid residue group (Group A) is 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, which is suitable for improving rigidity, and the aforementioned tetracarboxylic acid residue group (Group B) is selected from at least one of the group consisting of 4,4'-(hexafluoroisopropyl)diphthalic acid residue, 2,3',3,4'-biphenyltetracarboxylic acid residue, 3,3',4,4'-diphenyltetracarboxylic acid residue, 4,4'-oxodiphthalic acid residue, cyclohexanetetracarboxylic acid residue, and cyclopentanetetracarboxylic acid residue, which is suitable for improving transparency.

[0139] 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 content of the tetracarboxylic acid residue group (group A) suitable for improving rigidity is preferably 0.05 mol or more and 9 mol or less, more preferably 0.1 mol or more and 5 mol or less, and more preferably 0.3 mol or more and 4 mol or less, relative to 1 mol of the tetracarboxylic acid residue group (group B) suitable for improving transparency.

[0140] R2 in the above general formula (1) is preferably selected from at least one divalent group selected from the group consisting of 4,4'-diaminodiphenyl sulfone residue, 3,4'-diaminodiphenyl sulfone residue, and divalent groups represented by the above general formula (2) in terms of improving transparency and rigidity. More preferably, it is selected from at least one divalent group selected from the group consisting of 4,4'-diaminodiphenyl sulfone residue, 3,4'-diaminodiphenyl sulfone residue, and divalent groups represented by the above general formula (2) in which R3 and R4 are perfluoroalkyl groups.

[0141] R5 in the above general formula (3) is preferably composed of 4,4'-(hexafluoroisopropyl)diphthalic acid residue, 3,3',4,4'-diphenyltetracarboxylic acid residue and oxydiphthalic acid residue in terms of improving transparency and rigidity.

[0142] In R5, it is preferable to contain more than 50 mol% of the preferred residues, more preferably more preferably more than 70 mol% of the preferred residues, and even more preferably more than 90 mol% of the preferred residues.

[0143] R6 in the above general formula (3) 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. As R6 in the above general formula (3), in terms of improved transparency and increased rigidity, it is preferable to contain residues selected from 2,2'-bis(trifluoromethyl)benzidine residues, bis[4-(4-aminophenoxy)phenyl] benzoyl residues, 4,4'-diaminodiphenyl benzoyl residues, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residues, bis[4-(3-aminophenoxy)phenyl] benzoyl residues, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether residues, 1,4-bis[4-amino-2-(trifluoromethyl)phenoxy]phenyl residues, 2,2- The divalent group is selected from the group consisting of bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane residue, 4,4'-diamino-2-(trifluoromethyl)diphenyl ether residue, 4,4'-diaminobenzylaniline residue, N,N'-bis(4-aminophenyl)terephthalamide residue, and 9,9-bis(4-aminophenyl)benzyl residue, and more preferably contains at least one divalent group selected from the group consisting of 2,2'-bis(trifluoromethyl)benzylamine residue, bis[4-(4-aminophenyl)phenyl]benzyl residue, and 4,4'-diaminodiphenylbenzyl residue.

[0144] In R6, it is preferable that the total amount of such preferred residues is 50 mol% or more, more preferably that the total amount of such preferred residues is 70 mol% or more, and even more preferably that the total amount of such preferred residues is 90 mol% or more.

[0145] Furthermore, as R6, it is also preferable to use a mixture of the following diamine residue group (Group C) and the following diamine residue group (Group D), wherein the diamine residue group (Group C) is selected from at least one of the group consisting of bis[4-(4-aminophenoxy)phenyl] benzoyl residue, 4,4'-diaminobenzoniline residue, N,N'-bis(4-aminophenyl)-p-phenylenediamine residue, p-phenylenediamine residue, m-phenylenediamine residue, and 4,4'-diaminodiphenylmethane residue, which is suitable for improving rigidity; and the diamine residue group (Group D) is selected from 2,2'-bis(trifluoromethyl)benzidine residue. At least one of the following residues is suitable for enhancing transparency: 4,4'-diaminodiphenyl ether residue, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residue, bis[4-(3-aminophenoxy)phenyl] ether 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) phenoxy residue.

[0146] In this case, regarding the content ratio of the diamine residue group (group C) suitable for improving rigidity and the diamine residue group (group D) suitable for improving transparency, the content of the diamine residue group (group C) suitable for improving rigidity is preferably 0.05 mol or more and 9 mol or less, more preferably 0.1 mol or more and 5 mol or less, and more preferably 0.3 mol or more and 4 mol or less, relative to 1 mol of the diamine residue group (group D) suitable for improving transparency.

[0147] In the structures represented by the above general formula (1) and the above general formula (3), n and n' independently represent the number of repeating units, which is 1 or more. The number of repeating units n in polyimide is not particularly limited, and can be appropriately selected according to the structure. The average number of repeating units can be set to 10 or more and 2000 or less, preferably 15 or more and 1000 or less.

[0148] Furthermore, a portion of the polyimide may contain a polyimide structure. Examples of possible polyimide structures include: polyimide structures containing tricarboxylic acid residues, such as trimellitic anhydride, or polyimide structures containing dicarboxylic acid residues, such as terephthalic acid.

[0149] In terms of improving transparency and surface hardness, it is preferable that at least one of R1 or R5, which is a tetravalent group of a tetracarboxylic acid residue, and R2 or R6, which is a divalent group of a diamine residue, contains an aromatic ring and contains at least one of the group consisting of (i) a fluorine atom, (ii) an aliphatic ring, and (iii) an aromatic ring linked together by an alkyl group that can be substituted with a sulfonyl or fluorine group. By making the polyimide contain at least one of a tetracarboxylic acid residue having an aromatic ring and a diamine residue having an aromatic ring, the molecular skeleton becomes rigid, the alignment is improved, and the surface hardness is increased. However, the rigid aromatic ring skeleton tends to have an absorption wavelength that extends to a longer wavelength, and tends to have a reduced transmittance in the visible light region. On the other hand, if the polyimide contains (i) a fluorine atom, the electronic states within the polyimide skeleton are less prone to charge transfer, thus improving transparency.

[0150] Furthermore, if polyimide contains (ii) an aliphatic ring, it can cleave the conjugation of π electrons within the polyimide backbone, thereby hindering charge transfer within the backbone, thus improving transparency. Furthermore, if polyimide contains a structure in which aromatic rings are linked together by alkyl groups that can be substituted with sulfonyl or fluorine groups, it can cleave the conjugation of π electrons within the polyimide backbone, thereby hindering charge transfer within the backbone, thus improving transparency.

[0151] In terms of improving transparency and surface hardness, it is preferable that at least one of R1 or R5 as a tetravalent group of a tetracarboxylic acid residue and R2 or R6 as a divalent group of a diamine residue contains an aromatic ring and a fluorine atom, and it is preferable that the divalent group of R2 or R6 as a diamine residue contains an aromatic ring and a fluorine atom.

[0152] As a specific example of such polyimide, those with a specific structure described in International Publication No. 2018 / 070523 can be cited.

[0153] Polyimide can be synthesized by known methods. Furthermore, commercially available polyimide can be used. Examples of commercially available polyimide include Neopulim (registered trademark) manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0154] The weight-average molecular weight of the 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, thus making it impossible to obtain a substrate layer with a smooth surface and uniform thickness.

[0155] Furthermore, the weight-average molecular weight of polyimide can be determined by gel permeation chromatography (GPC). Specifically, polyimide is prepared into a 0.1% by mass 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, using a SHODEX-manufactured GPC LF-804 column) 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 based on a polystyrene standard sample of the same concentration as the sample.

[0156] (b) Polyamide-imide There are no particular limitations on the type of polyamide-imide, as long as a transparent resin substrate can be obtained. Examples include those having a first block containing a unit derived from a dianhydride and a unit derived from a diamine, and a second block containing a unit derived from an aromatic dicarbonyl compound and a unit derived from an aromatic diamine. In the above-mentioned polyamide-imide, the dianhydride may, for example, contain biphenyltetracarboxylic acid dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). Furthermore, the above-mentioned diamine may contain bis(trifluoromethyl)benzidine (TFDB). That is, the above-mentioned polyamide amide has the following structure, which is formed by amide imidization of a polyamide amide precursor having a first block copolymerized with monomers containing dianhydrides and diamines and a second block copolymerized with monomers containing aromatic dicarbonyl compounds and aromatic diamines.

[0157] The aforementioned polyamide-imidene, by having a first block containing amide bonds and a second block containing amide bonds, exhibits not only excellent optical properties but also excellent thermal and mechanical properties. In particular, by using bis(trifluoromethyl)benzidine (TFDB) as the diamine forming the first block, thermal stability and optical properties can be improved. Furthermore, by using 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic acid dianhydride (BPDA) as the dianhydrides forming the first block, birefringence can be improved and heat resistance can be ensured.

[0158] The dianhydride forming the first block contains two dianhydrides, namely 6FDA and BPDA. In the first block, the polymer formed by TFDB and 6FDA and the polymer formed by TFDB and BPDA can be separately contained based on other repeating units, or they can be regularly arranged in the same repeating unit, or they can be arranged completely randomly and contained therein.

[0159] The dianhydride in the monomer forming the first block preferably contains BPDA and 6FDA 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, and can have excellent birefringence.

[0160] 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 extremely low, the improvement in thermal stability and mechanical properties resulting from the second block cannot be fully obtained. Furthermore, when the content of the second block is higher than that of the first block, although thermal stability and mechanical properties can be improved, optical properties deteriorate, such as a decrease in yellowness or transmittance, and an increase in birefringence. Moreover, the first block and the second block can be random copolymers or block copolymers. There is no particular limitation on the repeating units of the blocks.

[0161] As an aromatic dicarbonyl compound forming the second block, examples include one or more selected from the group consisting of p-terephthaloyl chloride (TPC), terephthalic acid, isophthaloyl dichloride, and 4,4'-benzoyl chloride. Preferably, it is selected from one or more selected from p-terephthaloyl chloride (TPC) and isophthaloyl dichloride.

[0162] As a diamine forming the second block, examples selected include 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (HFBAPP), bis(4-(4-aminophenoxy)phenyl) benzo[a] (BAPS), bis(4-(3-aminophenoxy)phenyl) benzo[a] (BAPSM), 4,4'-diaminodiphenyl benzo[a] (4DDS), 3,3'-diaminodiphenyl benzo[a] (3DDS), 2,2-bis(4-(4-aminophenoxy)phenylpropane (BAPP), 4,4'-diaminodiphenylpropane (6HDA), and 1,3-bis(4-aminophenoxy)benzene (134). A diamine having a flexible group from the group consisting of APB, 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 ether (DABS), 2,2-bis(3-amino-4-hydroxyphenyl)propane (BAP), 4,4'-diaminodiphenylmethane (DDM), 4,4'-diaminodiphenyl ether (4-ODA) and 3,3'-diaminodiphenyl ether (3-ODA).

[0163] When using aromatic dicarbonyl compounds, it is easier to achieve higher thermal stability and mechanical properties, but there is a possibility that the benzene ring in the molecular structure exhibits higher birefringence. Therefore, in order to suppress the decrease in birefringence caused by the second block, it is preferable to use diamines with a flexible group introduced into the molecular structure. Specifically, the diamine is more preferably selected from one or more of bis(4-(3-aminophenoxy)phenyl) benzo[a] (BAPSM), 4,4'-diaminodiphenyl benzo[a] (4DDS), and 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (HFBAPP). In particular, the longer the length of the flexible group such as BAPSM, the better the birefringence of the diamine with the substituent in the meta position.

[0164] Regarding the polyamide imine precursor containing a first block of a dianhydride containing biphenyltetracarboxylic acid dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) copolymerized with a diamine containing bis(trifluoromethyl)benzidine (TFDB), and a second block of an aromatic dicarbonyl compound copolymerized with an aromatic diamine, the weight average molecular weight measured by GPC is preferably 200,000 or more and 215,000 or less, and the viscosity is preferably 2,400 poise or more and 2,600 poise or less.

[0165] Polyamide-imide can be obtained by amide-imidizing a polyamide-imide precursor. Furthermore, polyamide-imide can be used to obtain a polyamide-imide film. For methods of amide-imidizing a polyamide-imide precursor and methods of manufacturing a polyamide-imide film, please refer, for example, to Japanese Patent Publication No. 2018-506611.

[0166] (2) The glass substrate is not particularly limited 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 even more preferred. Commercially available glass substrates include, for example, Nippon Electric Glass's G-Leaf ultra-thin sheet glass or Matsunami Glass's ultra-thin film glass.

[0167] Furthermore, the glass constituting the glass substrate is preferably chemically strengthened glass. Chemically strengthened glass is superior in terms of its excellent mechanical strength, which allows it to be made thinner accordingly. Typically, chemically strengthened glass is a type of glass in which some ions are replaced near the surface of the glass, such as potassium replacing sodium, and the mechanical properties are strengthened by chemical methods, and a compressive stress layer is formed on the surface.

[0168] Examples of glass that constitute the substrate of chemically strengthened glass include: aluminosilicate glass, soda-lime glass, borosilicate glass, lead glass, alkali barium glass, aluminoborosilicate glass, etc.

[0169] Commercially available products that serve as chemically strengthened glass substrates include, for example, Corning Gorilla Glass, AGC Dragontrail, and Schott Chemical Strengthening Glass.

[0170] (3) Composition of the substrate layer As the substrate layer, it is preferable to be a polyimide resin substrate containing polyimide resin or a glass substrate. The reason is that a substrate layer with bending resistance, excellent hardness and transparency can be formed.

[0171] There is no particular limitation on the thickness of the substrate layer, as long as it is a thickness that allows for flexibility. It can be appropriately selected according to the type of substrate layer, etc.

[0172] The thickness of the resin substrate is preferably 10 μm to 100 μm, and more preferably 25 μm to 80 μm. By keeping the thickness of the resin substrate within the above range, good flexibility and sufficient hardness can be obtained. Furthermore, curling of the laminate for the display device can be suppressed. Moreover, it is preferable in terms of the lightweight nature of the laminate for the display device.

[0173] The thickness of the glass substrate is preferably 200 μm or less, more preferably 15 μm or more and 100 μm or less, further preferably 20 μm or more and 90 μm or less, and even more 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. Furthermore, curling of the laminate for the display device can be suppressed. Moreover, it is preferable in terms of the lightweight nature of the laminate for the display device.

[0174] 4. Second functional layer The laminate for display devices in this invention may 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: a hard coating layer, an anti-reflective layer, an anti-glare layer, an anti-scattering layer, and a base coating layer.

[0175] Furthermore, the second functional layer can be a single layer or multiple layers. Also, the second functional layer can be a layer with a single function or multiple layers with different functions.

[0176] (1) Hard coating For example, as shown in FIG4, the display device laminate of the present invention may have a hard coating 4 between the substrate layer 2 and the functional layer 3. The hard coating is a component used to improve surface hardness. By configuring the hard coating, scratch resistance can be improved. In particular, when the substrate layer is a resin substrate, scratch resistance can be effectively improved by configuring the hard coating.

[0177] As a material for hard coating, organic materials, inorganic materials, organic-inorganic composite materials, etc. can be used.

[0178] Preferably, the material of the hard coating is an organic material. Specifically, the hard coating is preferably a hardened material containing a resin composition of a polymerizable compound. The hardened material containing the resin composition of the polymerizable compound can be obtained by using a polymerization initiator as needed and carrying out a polymerization reaction of the polymerizable compound using known methods.

[0179] Furthermore, regarding polymeric compounds, the same as those described in the section on functional layers above, therefore the description here is omitted.

[0180] The hard coating may contain a polymerization initiator as needed. Furthermore, the polymerization initiator may be the same as that described in the section on functional layers above, so the description here is omitted.

[0181] Furthermore, the hard coating may contain an antistatic agent. Preferably, the hard coating contains an antistatic agent when the functional layer does not contain an antistatic agent. This imparts antistatic properties to the laminate for the display device. Furthermore, by adjusting the content of the antistatic agent, the absolute value of the charge on the functional layer side of the laminate for the display device after an eraser test can be adjusted to a specific range.

[0182] The type and content of the antistatic agent can be the same as those of the antistatic agent in the above-mentioned functional layer.

[0183] The hard coating may contain additives as needed. The additives may be selected appropriately according to the function imparted to the hard coating, and there are no particular limitations. Examples include: inorganic particles, organic particles, ultraviolet absorbers, infrared absorbers, antifouling agents, antiglare agents, leveling agents, surfactants, slip agents, various sensitizers, flame retardants, adhesion promoters, polymerization inhibitors, antioxidants, light stabilizers, surface modifiers, etc.

[0184] 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, further preferably 1.5 μm to 30 μm, and even more preferably 2 μm to 20 μm. By keeping the thickness of the hard coating within the above range, sufficient hardness can be obtained for the hard coating.

[0185] As a method for forming a hard coating, for example, a method of coating a hard coating resin composition containing the above-mentioned polymeric compound onto the above-mentioned substrate layer and then hardening it.

[0186] (2)Anti-reflective layer The laminate for display devices in this invention may have an anti-reflective layer as a second functional layer. The anti-reflective layer is usually disposed on the surface of the functional layer opposite to the substrate layer.

[0187] The anti-reflective layer can be composed of a single layer or multiple layers.

[0188] As an anti-reflective layer, ordinary anti-reflective layers can be used, such as: a single-layer film containing a material with a lower refractive index than the hard coating, or a multilayer film having a high refractive index layer and a low refractive index layer from the hard coating side, a multilayer film having alternating layers of high refractive index layer and low refractive index layer from the hard coating side, or a multilayer film having a medium refractive index layer, a high refractive index layer and a low refractive index layer in sequence from the hard coating side, etc.

[0189] When the antireflective layer is a single-layer film, the material contained in the single-layer film can be any material with a lower refractive index than the hard coating, such as magnesium fluoride.

[0190] Furthermore, when the antireflective layer is a multilayer film, the refractive index of the low-refractive-index layer is preferably 1.45 or less, and 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.

[0191] As a low refractive index layer, examples include: those containing hydrolytic condensation polymers of metal alkoxides, those containing low refractive index resins, those containing low refractive index particles, those containing adhesive resins and low refractive index particles, etc.

[0192] Hydrolyzed condensation polymers of metal alkoxides can be obtained, for example, by the sol-gel method.

[0193] For example, fluoropolymers can be listed as resins with low refractive index.

[0194] Furthermore, 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.

[0195] Methods for forming low-refractive-index layers include wet methods and dry methods. Examples of wet methods include: methods using metal alkoxides or the like to form the layer via a sol-gel process; 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 are superior in terms of production efficiency; among these, methods using compositions containing binder resins and low-refractive-index particles to form the layer are preferred.

[0196] Furthermore, the refractive index of the high refractive index layer is preferably 1.55 or higher and 1.85 or lower, and more preferably 1.58 or higher and 1.70 or lower. By setting the refractive index of the high refractive index layer to a specific value or higher, the anti-reflective properties become good. Furthermore, the upper limit of the high refractive index layer is actually 1.85 or lower.

[0197] As a high refractive index layer, examples include those containing adhesive resin and high refractive index particles.

[0198] As high refractive index particles, examples include: antimony pentoxide, zinc oxide, titanium oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, yttrium oxide, and zirconium oxide, etc.

[0199] The average particle size of the high refractive index particles is preferably 5 nm to 200 nm, more preferably 5 nm to 100 nm, and even more preferably 10 nm to 80 nm. By setting the average particle size to 5 nm or more, particle aggregation can be easily suppressed, and by setting the average particle size to 200 nm or less, whitening caused by particle diffusion that reduces visibility can be easily suppressed.

[0200] From the perspective of balancing the high refractive index of the coating film with the strength of the coating film, the content of high refractive index particles relative to 100 parts by mass of adhesive resin is preferably 50 parts by mass to 500 parts by mass, more preferably 100 parts by mass to 450 parts by mass, and even more preferably 200 parts by mass to 430 parts by mass.

[0201] As the adhesive resin contained in the high refractive index layer, a curable resin composition can be listed as a curable resin composition. As the curable resin composition, the same as that exemplified with respect to the hard coating can be used, and a photocurable resin composition is preferred.

[0202] 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 setting the thickness of the high refractive index layer to the above range, low reflectivity can be exhibited in a wide wavelength region in the visible light region (380 nm to 780 nm).

[0203] As a method for forming a high refractive index layer, for example, a method of forming a high refractive index layer by coating a composition containing an adhesive resin and high refractive index particles.

[0204] The thickness of the anti-reflective layer can be the same as that of a regular anti-reflective layer, and can be appropriately selected according to the layer composition of the anti-reflective layer.

[0205] As a method for forming an anti-reflective layer, examples include coating method, vapor deposition method, etc., which can be appropriately selected according to the material of the anti-reflective layer.

[0206] 5. Impact Absorbing Layer The laminate for a display device in this invention may 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 providing an impact absorbing layer, impact can be absorbed when an impact is applied to the laminate for a display device, thereby improving impact resistance. Furthermore, when the substrate layer is a glass substrate, cracking of the glass substrate can be suppressed.

[0207] There are no particular limitations on the material used for the impact-absorbing layer, as long as it can provide an impact-absorbing layer that is both shock-absorbing and transparent. Examples include: polyethylene terephthalate (PET), polyethylene naphthalate (PEN), urethane resin, epoxy resin, polyimide, polyamide-imide, acrylic resin, triacetyl cellulose (TAC), polysiloxane, etc. One of these materials may be used alone, or two or more may be used in combination.

[0208] The impact absorption layer may contain additives as needed. Examples of additives include: inorganic particles, organic particles, ultraviolet absorbers, antioxidants, light stabilizers, surfactants, adhesion enhancers, etc.

[0209] The thickness of the impact absorption layer can be any thickness that can absorb the impact. For example, it is preferable to set it to 7 μm or more and 150 μm or less, more preferably 10 μm or more and 120 μm or less, and even more preferably 15 μm or more and 100 μm or less.

[0210] As an impact-absorbing layer, a resin film may be used, for example. Alternatively, for example, an impact-absorbing layer may be formed by coating the substrate layer with a composition for an impact-absorbing layer.

[0211] 6. Adhesive layer for attachment For example, as shown in FIG5, the display device laminate of the present invention may have an adhesive layer 6 for attachment on the side of the substrate layer 2 opposite to the functional layer 3. The display device laminate can be attached to, for example, a display panel via the adhesive layer for attachment.

[0212] As for the adhesive used in the bonding layer, there is no particular limitation as long as it is transparent and can make the display device bonded to the display panel, etc., such as thermosetting adhesives, UV-curing adhesives, two-component curing adhesives, hot melt adhesives, pressure-sensitive adhesives (so-called adhesives), etc.

[0213] For example, as shown in FIG6, 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, that is, they are pressure-sensitive adhesive layers. Generally, the pressure-sensitive adhesive layer is a relatively soft layer among the adhesive layers containing adhesives described above. 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 laminate for the display device, the pressure-sensitive adhesive layer does not inhibit the deformation of the impact-absorbing layer, thus the impact-absorbing layer easily deforms and therefore exhibits a greater impact absorption effect.

[0214] The pressure-sensitive adhesive used in the pressure-sensitive adhesive layer can be, for example, acrylic adhesives, polysiloxane adhesives, rubber adhesives, amine ester adhesives, etc., and can be appropriately selected according to the material of the impact-absorbing layer. Among them, acrylic adhesives are preferred. This is because they have excellent transparency, weather resistance, durability, and heat resistance, and are also relatively inexpensive.

[0215] The thickness of the adhesive layer for attachment is preferably set to 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, there is a risk that the laminate for the display device may not be able to bond sufficiently to the display panel, etc. Furthermore, when 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 obtain an effect that allows the impact-absorbing layer to deform sufficiently 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, there is a risk that the flexibility may be damaged.

[0216] As an adhesive layer for attachment, an adhesive film may also be used, for example. Alternatively, an adhesive composition may be coated onto a support or substrate layer to form an adhesive layer for attachment.

[0217] 7. In the stacked body for display device in the present invention, interlayer bonding layers can be arranged between each layer.

[0218] The adhesive used as an interlayer bonding layer may be the same as the adhesive used in the bonding layer described above.

[0219] Wherein, as described above, 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, preferably a pressure-sensitive adhesive layer.

[0220] Regarding the pressure-sensitive adhesive layer, it can be the same as the pressure-sensitive adhesive layer used in the adhesive layer for attachment mentioned above.

[0221] The thickness and forming method of the interlayer bonding layer can be the same as those of the bonding layer for attachment described above.

[0222] 8. Other aspects of the laminate for display device The thickness of the laminate for 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 display device is within the above range, flexibility can be improved.

[0223] The laminate for a display device according to the present invention can be used in a display device as a front panel disposed on the viewer side, closer to the display panel. Preferably, the laminate for a display device according to the present invention is used in the front panel of flexible display devices such as foldable displays, rollable displays, and bendable displays. In particular, the laminate for a display device according to the present invention is preferably used in the front panel of foldable displays because it can improve wear resistance in the bent portion.

[0224] Furthermore, the display device laminate of the present invention can be used, for example, 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.

[0225] B. Display device The display device of the present invention includes a display panel and a laminate for the display device disposed on the observer side of the display panel.

[0226] FIG7 is a schematic cross-sectional view showing an example of a display device according to the present invention. As shown in FIG7, 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, via an adhesive layer 6 for attaching the display device laminate 1.

[0227] When the display device laminate of the present invention is disposed on the surface of the display device, it is disposed with the functional layer on the outside and the substrate layer on the inside.

[0228] There is no particular limitation on the method of disposing the display device using a laminate on the surface of the display device, for example, the method via an adhesive layer can be listed.

[0229] As a display panel in the present invention, examples include display panels used in display devices such as organic EL display devices and liquid crystal display devices.

[0230] The display device of the present invention may have a touch panel component between the display panel and the display device laminate.

[0231] Preferably, the display device in this invention is a flexible display device such as a foldable display, a rollable display, or a bendable display.

[0232] 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 display device of the present invention is suitable as a foldable display because of its excellent wear resistance in the bending portion.

[0233] Furthermore, the present invention is not limited to the embodiments described above. The embodiments described above are illustrative examples; any invention having a substantially identical structure and achieving the same effect as the technical concept described in the claims of this invention is included within the technical scope of this invention. [Examples]

[0234] Hereinafter, embodiments and comparative examples are shown to further illustrate the present invention.

[0235] [Example 1] (1) Formation of hard coating A First, the components are mixed in such a way as shown below to obtain a resin composition 1 for hard coating.

[0236] (Composition of Resin Composition 1 for Hard Coating) ・Amino acrylate (product name "8UX-141A", manufactured by Taisei Fine Chemicals Co., Ltd.): 100 parts by weight (100% conversion of solids content) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad184", manufactured by IGM Resins BV Co., Ltd.): 4 parts by weight ・Leveling agent (product name "BYK-UV3535", manufactured by BYK-Chemie Japan Co., Ltd.): 0.5 parts by weight (100% conversion of solids content) ・Methyl isobutyl ketone: 250 parts by weight

[0237] Next, using an 80 μm thick polyimide film (product name "Neopulim", manufactured by Mitsubishi Gas Chemical Co., Ltd.) as the substrate layer, the above-mentioned resin composition 1 for hard coating is coated on the substrate layer using a bar coater to form a coating film. Then, the coating film is heated at 80°C for 1 minute to evaporate the solvent in the coating film. The coating film is then irradiated with ultraviolet light using an ultraviolet irradiation device (manufactured by Fusion UV Systems Japan, light source H BULB) with an oxygen concentration of less than 100 ppm to achieve a cumulative light intensity of 70 mJ / cm2, thereby hardening the coating film to form a 9.0 μm thick hard coating A as the second functional layer.

[0238] (2) Formation of hard coating B First, the components are mixed in such a way as shown below to obtain resin composition 2 for hard coating.

[0239] (Composition of Resin Composition 2 for Hard Coating) ・Amino acrylate (Product name "8UX-015A", manufactured by Taisei Fine Chemicals Co., Ltd.): 100 parts by weight (100% conversion of solids content) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, Product name "Omnirad184", manufactured by IGM Resins BV): 4 parts by weight ・Antifouling agent (Product name "DAC-HP", manufactured by Daikin Industries, Ltd.): 0.5 parts by weight (100% conversion of solids content) ・Antistatic agent (Product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 1.5 parts by weight (100% conversion of solids content) ・Methyl isobutyl ketone: 250 parts by weight

[0240] Next, the resin composition 2 for the hard coating layer is applied to the hard coating layer A using a bar coater to form a coating film. Then, the coating film is heated at 50°C for 1 minute to evaporate the solvent in the coating film. The film is then irradiated with ultraviolet light using an ultraviolet irradiation device (manufactured by Fusion UV Systems Japan, light source H BULB) with an oxygen concentration of less than 100 ppm to achieve a cumulative light intensity of 360 mJ / cm2, thereby hardening the coating film to form a hard coating layer B with a thickness of 3.0 μm as a functional layer. In this manner, a laminate having a substrate layer, hard coating layer A (second functional layer), and hard coating layer B (functional layer) in sequence is obtained.

[0241] [Comparative Example 1] Except that the following hard coating resin composition 3 was used when forming hard coating layer B (functional layer), the laminate was made in the same manner as in Example 1.

[0242] (Composition of Resin Composition 3 for Hard Coating) ・Amino acrylate (Product name "8UX-141A", manufactured by Taishin Fine Chemical Co., Ltd.): 100 parts by weight (100% conversion of solids content) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, Product name "Omnirad184", manufactured by IGM Resins BV): 4 parts by weight ・Antifouling agent (Product name "DAC-HP", manufactured by Daikin Industries, Ltd.): 0.5 parts by weight (100% conversion of solids content) ・Methyl isobutyl ketone: 250 parts by weight

[0243] [Example 2] Except that a PET film with a thickness of 50 μm ("COSMOSHINE A4160" manufactured by Toyobo Co., Ltd.) was used as the substrate layer, the laminate was made in the same manner as in Example 1.

[0244] [Example 3] Except that when forming the hard coating layer B (functional layer), the following hard coating resin composition 4 is used and the thickness is set to 4.0 μm, the laminate is made in the same manner as in Example 2.

[0245] (Composition of Resin Composition 4 for Hard Coating) ・Amino acrylate (Product name "8UX-141A", manufactured by Taisei Fine Chemicals Co., Ltd.): 100 parts by weight (100% conversion of solids content) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, Product name "Omnirad184", manufactured by IGM Resins BV): 4 parts by weight ・Antifouling agent (Product name "DAC-HP", manufactured by Daikin Industries, Ltd.): 0.5 parts by weight (100% conversion of solids content) ・Antistatic agent (Product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 2 parts by weight (100% conversion of solids content) ・Methyl isobutyl ketone: 250 parts by weight

[0246] [Example 4] Except that a hard coating A (second functional layer) is not formed, and when forming a hard coating B (functional layer), the above-mentioned hard coating resin composition 4 is used and the thickness is set to 3.5 μm, the laminate is made in the same manner as in Example 2.

[0247] [Example 5] Except that the thickness of the hard coating layer B (functional layer) was set to 3.3 μm, the laminate was fabricated in the same manner as in Example 3.

[0248] [Example 6] Except that the thickness of the hard coating layer B (functional layer) was set to 3.8 μm, the laminate was fabricated in the same manner as in Example 3.

[0249] [Example 7] Except that when forming the hard coating layer B (functional layer), the following hard coating resin composition 5 was used and the thickness was set to 3.5 μm, the laminate was made in the same manner as in Example 3.

[0250] (Composition of Resin Composition 5 for Hard Coating) ・Amino acrylate (Product name "8UX-141A", manufactured by Taisei Fine Chemicals Co., Ltd.): 50 parts by weight (100% conversion of solids content) ・Amino acrylate (Product name "8UX-015A", manufactured by Taisei Fine Chemicals Co., Ltd.): 50 parts by weight (100% conversion of solids content) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, Product name "Omnirad184", manufactured by IGM Resins BV): 4 parts by weight ・Antifouling agent (Product name "DAC-HP", manufactured by Daikin Industries, Ltd.): 0.5 parts by weight (100% conversion of solids content) ・Antistatic agent (Product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 2 parts by weight (100% conversion of solids content) ・Methyl isobutyl ketone: 250 parts by weight

[0251] [Example 8] Except for the use of a hard coating resin composition 6 containing an antistatic agent in the second functional layer, the laminate was made in the same manner as in Example 2.

[0252] (Composition of Resin Composition 6 for Hard Coating) ・Amino ester acrylate (product name "8UX-141A", manufactured by Taisei Fine Chemicals Co., Ltd.): 100 parts by weight (100% conversion of solids content) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad184", manufactured by IGM Resins BV): 4 parts by weight ・Leveling agent (product name "BYK-UV3535", manufactured by BYK-Chemie Japan): 0.5 parts by weight (100% conversion of solids content) ・Antistatic agent (product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 2.5 parts by weight (100% conversion of solids content) ・Methyl isobutyl ketone: 250 parts by weight

[0253] [Example 9] Except that the hard coating resin composition 7 without antistatic agent is used in the functional layer, the laminate is made in the same manner as in Example 8.

[0254] (Composition of resin composition 7 for hard coating) ・Amino acrylate (product name "8UX-015A", manufactured by Taishin Fine Chemical Co., Ltd.): 100 parts by weight (100% conversion of solids content) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad184", manufactured by IGM Resins BV): 4 parts by weight ・Antifouling agent (product name "DAC-HP", manufactured by Daikin Industries, Ltd.): 0.5 parts by weight (100% conversion of solids content) ・Methyl isobutyl ketone: 250 parts by weight

[0255] [Example 10] Except that the thickness of the functional layer was set to 5.8 μm, the laminate was fabricated in the same manner as in Example 9.

[0256] [Example 11] Except that the thickness of the functional layer was set to 9.4 μm, the laminate was fabricated in the same manner as in Example 9.

[0257] [Example 12] First, a hard coating resin composition 8 was 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 was heated at 80°C for 1 minute to evaporate the solvent in the coating film. The coating film was then irradiated with ultraviolet light using an ultraviolet irradiation device (manufactured by Fusion UV Systems Japan, light source H BULB) with an oxygen concentration of less than 100 ppm to achieve a cumulative light intensity of 70 mJ / cm2, thereby hardening the coating film and forming a hard coating layer B (functional layer) with a thickness of 3.0 μm as the functional layer.

[0258] (Composition of Resin Composition 8 for Hard Coating) ・Amino acrylate (Product name "8UX-015A", manufactured by Taisei Fine Chemicals Co., Ltd.): 100 parts by weight (100% conversion of solids content) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, Product name "Omnirad184", manufactured by IGM Resins BV): 4 parts by weight ・Leveling agent (Product name "BYK-UV3535", manufactured by BYK-Chemie Japan): 0.5 parts by weight (100% conversion of solids content) ・Antistatic agent (Product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 1.5 parts by weight (100% conversion of solids content) ・Methyl isobutyl ketone: 250 parts by weight

[0259] Next, on the above-mentioned 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 to obtain a laminate.

[0260] (Composition of the antireflective layer (low refractive index)) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad 184", manufactured by IGM Resins BV): 3 parts by mass ・Amino ester acrylate (product name "8UX-047A", manufactured by Taishin Fine Chemicals): 25 parts by mass ・Polyfunctional acrylate (product name "M-510", manufactured by Toa Synthetic): 45 parts by mass ・Neopentyl tetraacrylate and neopentyl tetraacrylate (product name "M-450", manufactured by Toa Synthetic): 30 parts by mass ・Low refractive index particles (hollow silica, average primary particle size 50 nm, manufactured by Nichibukai Catalyst Chemicals): 120 parts by mass (100% conversion of solids content) ・Low refractive index particles (silica, average primary particle size 12 nm) (nm, manufactured by Nissan Chemical Industries, Ltd.): 15 parts by weight (100% conversion of solids) • Methyl isobutyl ketone: 270 parts by weight • Isopropanol: 40 parts by weight

[0261] (Processing conditions) After heating at 90°C for 1 minute, irradiate with ultraviolet light at an oxygen concentration of less than 100 ppm to make the cumulative light intensity 500 mJ / cm2.

[0262] [Example 13] 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 the following composition and processing conditions. Subsequently, an anti-reflective layer (low refractive index) identical to that fabricated in Example 12 was fabricated to obtain a laminate.

[0263] (Composition of the antireflective layer (high refractive index)) • Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad184", manufactured by IGM Resins BV): 3 parts by mass • Neopentyl tertetrol (tri / tetra) acrylate (product name "PETIA", manufactured by DAICL-ALLNEX): 80 parts by mass • Multifunctional acrylate (product name "M-510", manufactured by Toa Synthetic): 20 parts by mass • High refractive index particles (zirconia, average primary particle size 20 nm, manufactured by CIK NanoTek): 120 parts by mass (100% conversion of solids content) • Methyl isobutyl ketone: 270 parts by mass • Isopropanol: 40 parts by mass

[0264] (Processing conditions) After heating at 70°C for 1 minute, irradiate with ultraviolet light at an oxygen concentration of less than 100 ppm to make the cumulative light intensity 60 mJ / cm2.

[0265] [Example 14] Except that the thickness of the anti-reflection layer (high refractive index) was set to 190 nm, the laminate was obtained in the same manner as in Example 13.

[0266] [Comparative Example 2] Except that the thickness of the hard coating layer B (functional layer) was set to 3.0 μm, the laminate was made in the same manner as in Example 4.

[0267] [Comparative Example 3] Except that the thickness of the hard coating layer B (functional layer) was set to 2.5 μm, the laminate was fabricated in the same manner as in Example 3.

[0268] [Comparative Example 4] Except that when forming the hard coating layer B (functional layer), the following hard coating resin composition 9 was used and the thickness was set to 2.5 μm, the laminate was made in the same manner as in Example 3.

[0269] (Composition of Resin Composition 9 for Hard Coating) ・Amino ester acrylate (product name "8UX-141A", manufactured by Taisei Fine Chemicals Co., Ltd.): 100 parts by weight (100% conversion of solids content) ・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name "Omnirad184", manufactured by IGM Resins BV): 4 parts by weight ・Antifouling agent (product name "DAC-HP", manufactured by Daikin Industries, Ltd.): 0.5 parts by weight (100% conversion of solids content) ・Antistatic agent (product name "BEAMSET MT-2", manufactured by Arakawa Chemical Industry Co., Ltd.): 10 parts by weight (100% conversion of solids content) ・Methyl isobutyl ketone: 250 parts by weight

[0270] [Comparative Example 5] Except that the thickness of the functional layer was set to 10.3 μm, the laminate was fabricated in the same manner as in Example 9.

[0271] [Evaluation] (1) Charge after eraser test The following eraser test was performed on the functional layer side of the laminate of the embodiment and the comparative example to measure the charge on the functional layer side of the laminate after the eraser test.

[0272] First, under conditions of 23±5℃ and 40±10%RH, the ionizer was placed on a glass plate serving as a test bench for 1 minute to remove static electricity. Then, a 20 mm × 80 mm laminate was prepared, and under conditions of 23±5℃ and 40±10%RH, the ionizer was placed on both sides of the laminate for 30 to 60 seconds to remove static electricity.

[0273] Next, the end of the above-mentioned laminate was fixed to a glass plate with transparent tape, and an eraser test was performed on the functional layer side of the above-mentioned laminate. Specifically, an eraser with a diameter of 6 mm manufactured by Minoan was inserted into a fixture with a diameter of 6 mm with the front end of the eraser protruding 4 mm. The fixture with the eraser was installed on a vibratory friction fastness tester (product name "AB-301", manufactured by TESTER SANGYO). Under the conditions of temperature 23±5℃ and humidity 40±10%RH, with a load of 9.8 N, a moving speed of 80 mm / s and a moving distance of 40 mm, the functional layer side of the above-mentioned laminate was rubbed back and forth 2500 times by the eraser.

[0274] Next, the stack after the eraser test was placed in a Faraday cage, and the charge was measured. At this time, the stack after the eraser test was lifted using insulating and non-magnetic tweezers. After lifting the stack, the charge was measured without contact with other fixed surfaces. The Faraday cage used was the Kasuga Electric Corporation Faraday cage "KQ-1400". The ionizer used was the Kasuga Electric Corporation fan-type ionizer "KD-750B". The tweezers used were KENIS Corporation ESD (static discharge) tweezers "P-643-S".

[0275] (2)The frictional force before and after the eraser test was measured on the functional layer side surface of the laminate of the embodiment and the comparative example by the above eraser test, and the frictional force of the functional layer side surface of the laminate on the eraser before and after the eraser test was measured.

[0276] When measuring the frictional force on the eraser, a 6 mm diameter eraser manufactured by Minoan was used. The eraser was inserted into a fixture with a 6 mm diameter hole, with 4 mm of the front end protruding. The fixture with the eraser was mounted on a continuous loading scratch strength tester (product name "TRIBOGEAR TYPE18", manufactured by Shin Tung Science & Technology Co., Ltd.). Under conditions of 23±5℃ and 40±10%RH, with a load of 1.96 N and a moving speed of 840 mm / min, the eraser was used to rub the functional layer side of the laminate in the following order: the area where the eraser test was not performed, the area where the eraser test was performed, and the area where the eraser test was not performed again. The frictional force was measured. At this time, as shown in Figure 2, the eraser was moved perpendicularly to the long side of the rectangular eraser test area 32, as indicated by the arrow.

[0277] Then, regarding the frictional force between the eraser test section and the eraser, the maximum value of the frictional force is determined. Furthermore, regarding the frictional force between the eraser test non-test section and the eraser, as shown in Figure 2, when the point where the frictional force between the eraser test section 32 and the eraser reaches its maximum value is set to 0 mm, the average value of the frictional force in the eraser test non-test section 31, which is in the range of 4.2 mm to 9.8 mm with the above point (0 mm) as the reference, is determined.

[0278] Furthermore, regarding the ratio of frictional force before and after the eraser test, on the functional layer side of the aforementioned laminate, if the average value of the frictional force in the area where the eraser test was not performed is set as A, and the maximum value of the frictional force in the area where the eraser test was performed is set as B, the ratio of frictional force before and after the eraser test is calculated according to the following formula: Ratio of frictional force = B / A

[0279] (3) Sliding property before and after the eraser test The above-mentioned eraser test was performed on the functional layer side surface of the laminate of the embodiment and the comparative example, and the sliding property of the functional layer side surface of the laminate before and after the eraser test was evaluated. Specifically, the functional layer side surface of the laminate was rubbed with a fingertip in the order of the part not subjected to the eraser test, the part subjected to the eraser test, and the part not subjected to the eraser test, under the conditions of temperature 23±5℃ and humidity 40±10%RH, at a moving speed of 10 cm / s, and the sliding property of the part subjected to the eraser test was evaluated according to the following criteria.

[0280] A: More than 7 out of 10 people did not experience any lag. B: 5 or 6 out of 10 people did not experience any lag. C: 6 or 7 out of 10 people experienced lag. D: More than 8 out of 10 people experienced lag.

[0281] (4) Steel wool test First, a protective film with an adhesive layer on one side of a PET substrate (PET substrate thickness: 100 μm or more and 125 μm or less, adhesive layer thickness: 10 μm or more and 25 μm or less) is attached to the substrate side of a 4 cm × 10 cm laminate. Then, the end of the laminate is fixed to the test stand of the AB-301 vibration-type friction fastness tester manufactured by TESTER SANGYO Co., Ltd. with transparent tape. Next, using #0000 steel wool (BONSTAR #0000 manufactured by NIPPON STEEL WOOL), the steel wool was fixed to a 2 cm × 2 cm clamp and rubbed back and forth 2500 times on the functional layer side of the display device laminate under the following conditions: temperature 23±5℃, humidity 40±10%RH, load: 9.8 N, reciprocating speed: 40 rpm, reciprocating distance: 40 mm, and steel wool application area: 4 cm². Then, the presence or absence of scratches was checked by transmission and reflection.

[0282] [Table 1] Substrate layer Functional Layer 2 Functional layer Charge (nC) Average frictional force (N) Maximum frictional force (N) Ratio of friction Eraser test Sliding SW test Material thickness (μm) thickness (μm) thickness (μm) Resin components Antistatic agent addition amount (by weight) Before the eraser test (before the eraser test was conducted) After the eraser test (Eraser Test Implementation Department) Comparative Example 1 Polyimide 80 9.0 3.0 I 0 -11.91 4.84 8.71 1.80 D No scars Example 1 Polyimide 80 9.0 3.0 II 1.5 -0.70 4.12 5.40 1.31 A No scars Example 2 PET 50 9.0 3.0 II 1.5 -0.81 3.64 5.17 1.42 A No scars Example 3 PET 50 9.0 4.0 I 2 -2.10 3.94 5.32 1.35 A No scars Example 4 PET 50 - 3.5 I 2 -8.65 4.03 6.09 1.51 B No scars Example 5 PET 50 9.0 3.3 I 2 -9.46 4.30 7.12 1.66 C No scars Example 6 PET 50 9.0 3.8 I 2 -7.82 3.68 5.45 1.48 B No scars Example 7 PET 50 9.0 3.5 I+II 2 -5.35 4.10 5.94 1.45 B No scars Example 8 PET 50 9.0 3.0 II 1.5 -0.67 3.76 4.85 1.29 A No scars Example 9 PET 50 9.0 3.0 II 0 -2.89 4.03 5.96 1.48 B No scars Example 10 PET 50 9.0 5.8 II 0 -6.77 4.09 6.42 1.57 B No scars Example 11 PET 50 9.0 9.4 II 0 -9.78 4.41 7.40 1.68 C No scars Example 12 PET 50 9.0 3.0 II 1.5 -0.93 3.81 5.60 1.47 A No scars Example 13 PET 50 9.0 3.0 II 1.5 -0.97 3.89 5.83 1.50 A No scars Example 14 PET 50 9.0 3.0 II 1.5 -1.22 3.87 5.88 1.52 A No scars Comparative Example 2 PET 50 - 3.0 I 2 -10.40 4.65 8.14 1.75 D No scars Comparative Example 3 PET 50 9.0 2.5 I 2 -16.17 5.05 9.39 1.86 D No scars Comparative Example 4 PET 50 9.0 2.5 I 10 -23.10 4.21 9.83 2.33 D There are scars Comparative Example 5 PET 50 9.0 10.3 II 0 -13.23 4.67 8.35 1.79 D No scars

[0283] (5) The ratio of the number of fluorine atoms to the total number of atoms of all elements before and after the eraser test. The eraser test was performed on the functional layer side of the laminate of Example 1 and Comparative Example 1. The composition of the functional layer side of the laminate and the eraser side before and after the eraser test was analyzed by X-ray photoelectron spectroscopy (XPS). First, using an X-ray photoelectron spectrometer (AXIS-NOVA manufactured by Kratos), X-rays were irradiated from the sample surface toward the depth direction under the following conditions, and the X-ray photoelectron spectra of C, O, F, N, Si, Ca, and Cl were measured as the elements to be analyzed.

[0284] Subtract the background value determined by the Shirley method from the obtained spectrum, and use the relative sensitivity coefficient method based on the peak area to determine the ratio of the number of atoms of each element on the sample surface to the total number of atoms of all elements (the ratio of the number of atoms of each element (at%) when the total number of atoms of carbon, oxygen, fluorine, nitrogen, silicon, calcium, and chlorine is set to 100 at%). The results are shown in Tables 2 and 3.

[0285] (Measurement Conditions) • Incident X-rays: Monochromated Al-Kα rays (Hv = 1486.6 eV) • X-ray irradiation area (measurement area): 110 μm • X-ray output: 150 W (15 kV, 6.7 mA) • Photoelectron receiving angle: 90° ± 15° (with the sample normal set to 0°) • Charge neutralization conditions: Electron neutralization gun (+6 V, 0.05 mA), low-acceleration Ar+ ion irradiation • Measurement peaks: C1s, O1s, F1s, N1s, Si2p, Ca2p, Cl2p

[0286] [Table 2] Example 1 C 1s O 1s F 1s N 1s Si 2p Ca 2p Cl 2p Functional layer side surface of the laminate Before the eraser test (The eraser test was not conducted in this section) 48.28 20.56 28.50 1.73 0.95 - - After the eraser test (Eraser Test Implementation Department) 52.18 21.32 23.29 2.25 0.96 - - Eraser face Before the eraser test 69.82 19.68 - - - 3.87 6.63 After the eraser test 67.81 20.15 2.34 - - 4.21 5.49

[0287] [Table 3] Comparative Example 1 C 1s O 1s F 1s N 1s Si 2p Ca 2p Cl 2p Functional layer side surface of the laminate Before the eraser test (The eraser test was not conducted in this section) 47.10 19.47 30.94 1.62 0.87 - - After the eraser test (Eraser Test Implementation Department) 63.03 25.17 8.33 2.59 0.88 - - Eraser face Before the eraser test 69.52 19.81 - - - 4.02 6.65 After the eraser test 55.37 20.75 14.28 - - 4.76 4.84

[0288] As confirmed by Tables 2-3, after the eraser test, the proportion of fluorine atoms on the functional layer side of the laminate to the total number of atoms of all elements decreased, while the proportion of fluorine atoms on the eraser surface to the total number of atoms of all elements increased. This confirms that by rubbing the functional layer side of the laminate with an eraser, fluorine atoms contained in the functional layer adhere to the eraser. It is believed that this is because, by rubbing the functional layer side of the laminate with an eraser, the surface of the functional layer becomes negatively charged, which in turn makes the contact surface of the eraser positively charged. As a result, the electrostatic force increases, and the attraction increases. Therefore, the more negatively charged fluorine atoms detach from the surface of the functional layer and adhere to the surface of the eraser.

[0289] Furthermore, as confirmed by Table 1, when the absolute value of the charge on the functional layer side of the laminate after the eraser test is within a specific range, the change in sliding properties before and after the eraser test is smaller, and the wear resistance is excellent. This is believed to be because by keeping the absolute value of the charge on the functional layer side of the laminate after the eraser test within a specific range, the detachment of fluorine from the surface of the functional layer can be suppressed, resulting in excellent wear resistance.

[0290] That is, the present invention can provide the following invention. [1] A multilayer for a display device having a substrate layer and a fluorine-containing functional layer, and after performing an eraser test in which a load of 9.8 N is applied to the functional layer side surface of the multilayer for the display device using an eraser with a diameter of 6 mm and the two sides are rubbed back and forth 2500 times, the absolute value of the charge on the functional layer side surface of the multilayer for the display device is 10.0 nC or less. [2] The multilayer for a display device as described in [1], wherein the ratio of the initial average value of the frictional force against the eraser on the functional layer side surface of the initial multilayer for the display device to the maximum value of the frictional force against the eraser after the eraser test is 1.7 or less. [3] The laminate for a display device as described in [1] or [2], wherein the ratio of the number of fluorine atoms on the functional layer side surface to the total number of atoms of all elements after the eraser test is 0.4 or more, relative to the ratio of the number of fluorine atoms on the functional layer side surface to the total number of atoms of all elements as measured by X-ray photoelectron spectroscopy. [4] The laminate for a display device as described in any one of [1] to [3], wherein the functional layer contains an antistatic agent. [5] The laminate for a display device as described in [4], wherein the antistatic agent is a conductive polymer. [6] The 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. [7] The display device laminate as described in any one of [1] to [6] has an adhesive layer for attachment on the side of the substrate layer opposite to the functional layer. [8] The display device laminate as described in any one of [1] to [7] has a distance of 10 μm or less between the outermost surface of the functional layer side of the display device laminate and the layer containing the antistatic agent. [9] The display device laminate as described in any one of [1] to [8] has an anti-reflective layer disposed on the outermost surface of the functional layer side of the display device laminate.

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

[0021] [Figure 1] is a schematic cross-sectional view illustrating the laminated body for a display device according to the present invention. [Figure 2] is a schematic diagram illustrating a method for measuring the frictional force of an eraser. [Figure 3] is a schematic diagram illustrating a dynamic bending test. [Figure 4] is a schematic cross-sectional view illustrating the laminated body for a display device according to the present invention. [Figure 5] is a schematic cross-sectional view illustrating the laminated body for a display device according to the present invention. [Figure 6] is a schematic cross-sectional view illustrating the laminated body for a display device according to the present invention. [Figure 7] is a schematic cross-sectional view illustrating the display device according to the present invention.

Claims

1. A multilayer for a display device, comprising a substrate layer and a fluorinated functional layer, wherein after an eraser test in which a load of 9.8 N is applied to the outermost surface of the multilayer for the display device on the side of the functional layer using an eraser with a diameter of 6 mm and the test is repeated 2500 times, the absolute value of the charge on the outermost surface of the multilayer for the display device on the side of the functional layer is 10.0 nC or less, and the fluorinated compound in the fluorinated functional layer is biased on the side of the functional layer opposite to the substrate layer.

2. As in the display device laminate of request item 1, wherein, The ratio of the initial average friction force against the eraser on the outermost surface of the functional layer side of the aforementioned laminated body for the display device to the maximum value of the friction force against the eraser after the eraser test is 1.7 or less.

3. As in claim 1, the display device laminate, wherein, Compared to the ratio of the number of fluorine atoms on the outermost surface of the aforementioned functional layer to the total number of atoms of all elements as measured by X-ray photoelectron spectroscopy, the ratio of the number of fluorine atoms on the outermost surface of the aforementioned functional layer to the total number of atoms of all elements after the aforementioned eraser test is 0.4 or higher.

4. As in claim 1, the display device laminate, wherein, The aforementioned functional layer contains an antistatic agent.

5. As in claim 4, the laminate for the display device, wherein, The above-mentioned antistatic agent is a conductive polymer.

6. The laminate for a display device as claimed in claim 1, having 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.

7. The display device laminate of claim 1, wherein the substrate layer has an adhesive layer on the side opposite to the functional layer.

8. As in claim 1, the display device laminate, wherein, The distance between the outermost surface of the functional layer side of the aforementioned display device laminate and the layer containing the antistatic agent is less than 10 μm. The layer containing the antistatic agent is the first layer containing the antistatic agent when viewed from the outermost surface side of the functional layer side towards the substrate layer side.

9. The display device laminate of claim 1, wherein an anti-reflective layer is disposed on the outermost surface of the functional layer side of the display device laminate.

10. A display device comprising: a display panel, and a display device laminate disposed on the observer side of the display panel according to any one of claims 1 to 9.

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