Optical laminate, and antireflection article, panel, and image display device using the same

Abstract

Provided is an optical laminate that has good antireflection properties even when applied to a component having a non-flat shape. An optical laminate that has, in order, a hard coat layer and a low-refractive layer on a resin substrate, and satisfies conditions 1 and 2. Condition 1: A first sample of 20 mm x 100 mm in size is cut out from the optical laminate, the first sample is set to a tensile testing machine at a chuck distance of 50 mm, and the elongation at the upper yield point of the first sample when the first sample is stretched in the long side direction at 130°C at a stretching speed of 50 mm / min is 6.5% or more. Condition 2: The average of the thickness of the low-refractive layer before the optical laminate is elongated is set to t1, the average of the thickness of the low-refractive layer after elongation measured under prescribed conditions is set to t2, and the ratio of the thickness of the low-refractive layer after elongation (t2) to the thickness of the low-refractive layer before elongation (t1) calculated from the following formula is 80% or more and 99% or less.

Description

Technical Field

[0001] This disclosure relates to optical laminates, and anti-reflective articles, panels, and image display devices using said optical laminates. Background Technology

[0002] To ensure good visibility, anti-reflective films are sometimes applied to the surfaces of image display devices such as liquid crystal displays, organic EL displays, and miniature LED displays. Additionally, anti-reflective films are sometimes applied to the surfaces of items such as display cases.

[0003] As an anti-reflective film, an optical laminate having an anti-reflective layer such as a low refractive index layer on a substrate has been proposed (Patent Document 1, etc.).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-150906 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Most image display devices to date are flat in shape. Therefore, optical laminates with anti-reflective layers can be applied to flat shapes without any problems, as long as they provide good anti-reflective properties.

[0009] However, in recent years, display devices with non-flat shapes, such as curved display devices and three-dimensional display devices, have been developed. For such non-flat display devices, non-flat display cases, and other non-flat components, when using conventional optical laminates with anti-reflective layers, as in Patent Document 1, the reflectivity often exceeds the theoretical value.

[0010] The present disclosure aims to provide an optical laminate that provides good anti-reflective properties even when applied to components with non-planar shapes. Furthermore, the present disclosure aims to provide anti-reflective articles, panels, and image display devices using the aforementioned optical laminate.

[0011] Methods for solving problems

[0012] This disclosure provides the following (1) to (4).

[0013] (1) An optical laminate having a hard coating layer and a low refractive index layer sequentially on a resin substrate, wherein, The optical laminate satisfies the following conditions 1 and 2: <Condition 1> A first sample with a short side of 20mm and a long side of 100mm is cut from the optical laminate. The first sample is placed in a tensile testing machine with a chuck spacing of 50mm. When the first sample is stretched in the long side direction at 130°C and a tensile speed of 50mm / min, the elongation at the upper yield point of the first sample is 6.5% or more. <Condition 2> Let t1 be the average thickness of the low-refractive-index layer before the optical laminate is stretched. A second sample with a short side of 20mm and a long side of 100mm was cut from the optical laminate. After marking the second sample with 50mm intervals, it was preheated at 130°C for 2 minutes. After preheating, the second sample was quickly placed in a tensile testing machine with the chucks spaced at the same distance as the preheated marks. The second sample was stretched along its long side at 130°C and a stretching speed of 50mm / min. Stretching was stopped when the chucks reached a distance of 60mm. The second sample was then removed from the tensile testing machine and placed at 23°C for 120 minutes. The thickness of the low-refractive-index layer after elongation was then measured, and the average thickness of the elongated low-refractive-index layer was defined as t2. The ratio of the thickness of the elongated low-refractive-index layer to the thickness of the unelongated low-refractive-index layer, calculated by the following formula, is 80% or more and 99% or less: The ratio (%) of the thickness of the elongated low-refractive-index layer to the thickness of the low-refractive-index layer before elongation = (t2 / t1) × 100.

[0014] (2) An antireflective article having a component and an optical laminate of (1) disposed on the component, the antireflective article being configured such that the low refractive index layer side of the optical laminate faces the side opposite to the component.

[0015] (3) A panel having a display element and an optical film disposed on the light-emitting surface side of the display element, wherein, The panel includes the optical laminate described in (1) as the optical film, and the panel is configured such that the low refractive index layer side of the optical laminate faces the side opposite to the display element.

[0016] (4) An image display device comprising the panel described in (3).

[0017] Invention Effects

[0018] The optical laminate of this disclosure provides good anti-reflective properties even when applied to components with non-planar shapes. Regarding the anti-reflective articles, panels, and image display devices of this disclosure, good anti-reflective properties are achieved even when their shapes are non-planar. Attached Figure Description

[0019] Figure 1 This is a schematic cross-sectional view illustrating one embodiment of the optical laminate of this disclosure.

[0020] Figure 2 This is a cross-sectional view showing one embodiment of the panel of this disclosure.

[0021] Figure 3 This is a top view used to illustrate the second and third samples used in conditions 2 and 3. Detailed Implementation

[0022] The embodiments of this disclosure will now be described.

[0023] [Optical laminate]

[0024] The optical laminate disclosed herein is an optical laminate having a hard coating layer and a low refractive index layer sequentially on a resin substrate, wherein, The optical laminate satisfies the following conditions 1 and 2: <Condition 1> A first sample with a short side of 20mm and a long side of 100mm is cut from the optical laminate. The first sample is placed in a tensile testing machine with a chuck spacing of 50mm. When the first sample is stretched in the long side direction at 130°C and a tensile speed of 50mm / min, the elongation at the upper yield point of the first sample is 6.5% or more. <Condition 2> Let t1 be the average thickness of the low-refractive-index layer before the optical laminate is stretched. A second sample with a short side of 20mm and a long side of 100mm was cut from the optical laminate. After marking the second sample with 50mm intervals, it was preheated at 130°C for 2 minutes. After preheating, the second sample was quickly placed in a tensile testing machine with the chucks spaced at the same distance as the preheated marks. The second sample was stretched along its long side at 130°C and a stretching speed of 50mm / min. Stretching was stopped when the chucks reached a distance of 60mm. The second sample was then removed from the tensile testing machine and placed at 23°C for 120 minutes. The thickness of the low-refractive-index layer after elongation was then measured, and the average thickness of the elongated low-refractive-index layer was defined as t2. The ratio of the thickness of the elongated low-refractive-index layer to the thickness of the unelongated low-refractive-index layer, calculated by the following formula, is 80% or more and 99% or less: The ratio (%) of the thickness of the elongated low-refractive-index layer to the thickness of the low-refractive-index layer before elongation = (t2 / t1) × 100.

[0025] Figure 1 This is a schematic cross-sectional view showing the cross-sectional shape of the optical laminate 100 of this disclosure.

[0026] Figure 1 The optical laminate 100 has a hard coating layer 20 and a low refractive index layer 40 sequentially on the resin substrate 10. Figure 1 The optical laminate 100 also has a high refractive index layer 30 between the hard coating layer 20 and the low refractive index layer 40.

[0027] Figure 1 It is a schematic cross-sectional view. That is, in Figure 1 In this diagram, the scales of each layer constituting the optical laminate 100 are schematic for ease of illustration and differ from the actual scales. Figure 2 The same applies to other attached diagrams.

[0028] The optical laminates disclosed herein are not limited to Figure 1 The structure is composed of layers. For example, the optical laminate of this disclosure may also have a layered structure. Figure 1 Other layers not recorded in the text.

[0029] <Condition 1>

[0030] Condition 1 specifies that the elongation at the upper yield point of the first sample is 6.5% or more. The elongation at the upper yield point of the first sample can be considered as the elongation at the upper yield point of the optical laminate. That is, the optical laminate of this disclosure needs to have an elongation at the upper yield point of 6.5% or more.

[0031] When the elongation at the upper yield point is less than 6.5%, it is difficult to apply the optical laminate to components with non-planar shapes. The elongation at the upper yield point is preferably 6.7% or more, more preferably 6.9% or more, and even more preferably 7.0% or more.

[0032] The hard coating significantly affects the upper yield point of the optical laminate. On the other hand, the low-refractive-index and high-refractive-index layers have less impact on the upper yield point due to their thinness. Therefore, reducing the crosslinking density or thinning the hard coating tends to increase the elongation at the upper yield point. However, reducing the crosslinking density or thinning the hard coating also reduces the surface hardness of the hard coating, which in turn tends to reduce the surface hardness of the optical laminate. If the surface hardness of the optical laminate decreases, its scratch resistance tends to decrease. Therefore, the elongation at the upper yield point is preferably 17.0% or less, more preferably 15.0% or less, and even more preferably 12.0% or less.

[0033] In the components shown in this specification, when options for upper and lower limits of multiple values ​​are shown respectively, embodiments are described that combine a range formed by selecting one from the upper limit option and one from the lower limit option. For example, as embodiments of the range of elongation at the upper yield point, examples include 6.5% or more and 17.0% or less, 6.5% or more and 15.0% or less, 6.5% or more and 12.0% or less, 6.7% or more and 17.0% or less, 6.7% or more and 15.0% or less, 6.7% or more and 12.0% or less, 7.0% or more and 17.0% or less, 7.0% or more and 15.0% or less, and 7.0% or more and 12.0% or less.

[0034] Regarding condition 1, more specifically, the measurement shall be performed according to the steps A1 to A6 below.

[0035] A1: Cut the first sample, with a short side of 20mm and a long side of 100mm, from the optical laminate. Prepare 10 samples.

[0036] A2: Place the first sample on the tensile testing machine with a chuck spacing of 50 mm. At this time, use a pair of chucks of the tensile testing machine to fix the two ends of the short side of the first sample.

[0037] A3: Heat the first sample to 130°C.

[0038] In A3 above, the first sample can be heated, for example, by the heating system of a tensile testing machine.

[0039] A4: With both ends of the first sample fixed, it is stretched at 130°C and a stretching speed of 50 mm / min to impart strain to the first sample.

[0040] A5: Calculate the upper yield point and the elongation at the upper yield point based on the stress-strain curve with the elongation of the first sample on the horizontal axis and the tensile stress on the vertical axis.

[0041] In this specification, "upper yield point" refers to the location where the "tensile yield strain" of JIS K7161:2014 is achieved. In other words, in this specification, "upper yield point" refers to the initial location where strain increases without accompanying an increase in stress.

[0042] A6: Perform A2 to A5 on 10 samples. Take the average elongation at the upper yield point of the 10 samples as the elongation at the upper yield point of the optical laminate.

[0043] Regarding tensile testing machines, use tensile testing machines that can control the temperature.

[0044] In this specification, the elongation at the upper yield point is calculated using the following formula. In the following formula, "the distance between the chucks before stretching" is 50 mm when the first sample is placed in the tensile testing machine. The temperature when the first sample is placed in the tensile testing machine is set to 23°C.

[0045] Elongation at the upper yield point (%) = {(Distance between chucks at the upper yield point - Distance between chucks before stretching) / Distance between chucks before stretching} × 100

[0046] The "load at the upper yield point" mentioned later can be calculated by dividing the stress (N) at the upper yield point by the area of ​​the sample located between the chucks before tension (1000 mm²). 2 ) to calculate.

[0047] To easily meet condition 1, it is preferable to use an easily stretchable substrate as the resin substrate, or to adjust the crosslinking density and thickness of the hard coating. Detailed methods are described in the embodiments concerning the resin substrate and the hard coating.

[0048] The load at the upper yield point measured under condition 1 is preferably 7.0 mN / mm. 2 The following is more preferably 6.0 mN / mm 2 Hereinafter, 5.0 mN / mm is further preferred. 2 The following is an example of setting the load to 7.0 mN / mm. 2 The following makes it easy to apply optical laminates to parts with non-flat shapes with good workability.

[0049] If the load is too small, the scratch resistance of the optical laminate will easily decrease. Therefore, the load is preferably 1.6 mN / mm. 2 The above, more preferably 2.0 mN / mm 2 above.

[0050] <Condition 2>

[0051] Condition 2 specifies that the ratio of the thickness of the elongated low-refractive-index layer to the thickness of the low-refractive-index layer before elongation is more than 80% and less than 99%.

[0052] In this specification, the "ratio of the thickness of the elongated low-refractive-index layer to the thickness of the low-refractive-index layer before elongation" is sometimes referred to as the "ratio of the thickness of the low-refractive-index layer before and after elongation".

[0053] In this specification, the "ratio of the thickness of the elongated high refractive index layer to the thickness of the high refractive index layer before elongation" is sometimes referred to as the "ratio of the thickness of the high refractive index layer before and after elongation".

[0054] Regarding the optical laminate, it is applied to a non-planar part by stretching the optical laminate while fitting it to the part. Furthermore, in the above application, the optical laminate is heated to a specified temperature to facilitate stretching. In condition 2, a second sample made from the optical laminate is stretched by 10 mm at 130°C, thus reproducing the state of applying the optical laminate to a non-planar part (Note: In condition 2, the initial distance between the markings is 50 mm. Moreover, after setting the second sample so that the distance between the chucks matches the distance between the markings, the second sample is stretched until the distance between the chucks reaches 60 mm. Therefore, in condition 2, the second sample is stretched by the difference between 60 mm and 50 mm, i.e., 10 mm). Furthermore, in condition 2, it is placed at 23°C for 120 minutes, and then the thickness of the low-refractive-index layer after stretching is measured, thus the thickness is measured after the physical properties changed due to heating have stabilized. Therefore, in condition 2, it can be said that the state of applying the optical laminate to a component with a non-planar shape and the state after the optical laminate is stabilized are reproduced.

[0055] Therefore, it can be said that the "ratio of the thickness of the low-refractive-index layer before and after elongation" in condition 2 means "the ratio of the thickness of the low-refractive-index layer before and after applying the optical laminate to a non-planar part". Similarly, the "ratio of the thickness of the high-refractive-index layer before and after elongation" in condition 3, which will be described later, can be said to mean "the ratio of the thickness of the high-refractive-index layer before and after applying the optical laminate to a non-planar part".

[0056] In condition 2, a thickness change rate of less than 80% means that the low-refractive-index layer becomes too thin after applying the optical laminate to a non-planar component. Therefore, in condition 2, when the thickness change rate is less than 80%, good anti-reflective properties cannot be achieved when applied to a non-planar component.

[0057] In condition 2, since the distance between the markings is extended from 50 mm to 60 mm, the elongation rate of the extended portion is 20%. Therefore, if considered alone, the thickness of the second sample decreases by 20% after elongation, and the ratio of the thickness of the low-refractive-index layer before and after elongation is approximately 80%. However, for the following reasons, the ratio of the thickness of the low-refractive-index layer before and after elongation is generally a value greater than 80%.

[0058] First, when the low-refractive-index layer contains large particles such as hollow particles, the thickness of the areas containing these large particles does not easily change during elongation (on the other hand, in areas without large particles, the thickness tends to decrease due to the stretching of the adhesive resin). Furthermore, the hard coating typically contains cross-linked resin. Therefore, when the optical laminate is applied to a non-planar part while heated, the unreacted cross-linked resin in the hard coating undergoes cross-linking. If the hard coating cross-links, it shrinks, and due to the thickness of the hard coating, the low-refractive-index layer also shrinks. Moreover, the thickness of the low-refractive-index layer increases corresponding to its own degree of shrinkage. Therefore, the thickness change rate of the low-refractive-index layer in the second sample is greater than 80%. Furthermore, it can be said that the greater the thickness change rate of the low-refractive-index layer exceeds 80%, the greater the increase in the thickness of the low-refractive-index layer due to the shrinkage of the hard coating.

[0059] When the thickness of a low-refractive-index layer increases due to contraction, cracks are more likely to form in the low-refractive-index layer, or the arrangement of hollow particles may become disordered. Therefore, when the thickness of a low-refractive-index layer increases significantly due to contraction, the physical properties of the low-refractive-index layer are prone to change.

[0060] Therefore, in condition 2, a thickness variation rate exceeding 99% means that, due to the shrinkage of the hard coating, the thickness variation rate of the low-refractive-index layer is significantly increased compared to the theoretical value of 80%. Regarding low-refractive-index layers with such a significant increase in thickness, as mentioned above, cracks are prone to form in the low-refractive-index layer, or the arrangement of hollow particles is easily disrupted, thus hindering good anti-reflective properties. Therefore, in condition 2, when the thickness variation rate exceeds 99%, good anti-reflective properties cannot be achieved when applied to components with non-flat shapes.

[0061] In condition 2, the thickness change rate of the low refractive index layer before and after elongation is preferably 82% or more and 97% or less, more preferably 84% or more and 95% or less, and even more preferably 86% or more and 93% or less.

[0062] In condition 2, more specifically, the measurement shall be performed according to the steps B1 to B7 below.

[0063] B1: Set the average thickness of the low-refractive-index layer before the optical laminate is stretched to t1.

[0064] In this specification, the average thickness t1 of the low-refractive-index layer before the optical laminate is elongated is measured according to the steps (a1) and (a2) below.

[0065] (a1) Prepare a sample for measuring the film thickness by exposing the cross section of the optical laminate.

[0066] (a2) Use STEM to photograph the cross-section of the above sample at two locations. Extract the thickness of the low-refractive-index layer at 5 locations from each of the 2 images, for a total of 10 thicknesses. Average the thicknesses at the 10 locations to calculate the average t1 of the low-refractive-index layer thickness.

[0067] In this specification, the “low refractive index layer” in (a2) above is replaced with “high refractive index layer” or “hard coating” to calculate the average t3 of the thickness of the high refractive index layer before the optical laminate is stretched and the average t5 of the thickness of the hard coating before the optical laminate is stretched.

[0068] The sample that exposes the cross section of the optical laminate as described in (a1) above shall be prepared according to the steps X1 to X2 below.

[0069] X1: The optical laminate is bonded to the black plate using an optically transparent adhesive sheet to create a cut sample that can be cut to any size. For example, the size of the cut sample can be set as a strip with a length of 10mm and a width of 3mm.

[0070] X2: The sample is cut perpendicularly to create a slice of the optical laminate with exposed cross-section. For the cut sample, a glass cutter and a diamond cutter are used, and a slicer is employed for cutting.

[0071] When cutting the sample using a microtome, the initial rough cutting is done with a glass cutter to create a cross-section approximately 100 μm long × 20 μm wide, including the coated surface (rough trimming). Finally, the cross-section is cut with a diamond cutter, and slices floating on the water are collected using a sieve.

[0072] B2: Cut a second sample with a short side of 20mm and a long side of 100mm from the above optical laminate.

[0073] B3: After marking the second sample with 50mm intervals, preheat it at 130℃ for 2 minutes. After preheating, quickly place the second sample into the tensile testing machine. The distance between the chucks of the tensile testing machine should be the same as the distance between the marks after preheating.

[0074] In B3 above, the temperature was set to 23℃ when marking the second sample with 50mm intervals.

[0075] In step B3 above, after marking the second sample with lines spaced 50 mm apart, it is preheated at 130°C for 2 minutes. By preheating at the same temperature as in step B4, it is possible to suppress the elongation of the sample due to residual heat after step B4. Therefore, it is possible to reduce the thickness variation of the low-refractive-index layer caused by elongation due to residual heat after step 4.

[0076] In B3 above, before placing the preheated second sample into the tensile testing machine, a quantity of heat-resistant material is wound around both ends of the long side of the preheated second sample for 2 turns. Figure 3 The part wrapped with the heat-resistant material should be placed on the outside of the marking. Figure 3 In the diagram, section number 201 is the part wrapped with heat-resistant material. Figure 3 In the diagram, the label L corresponds to the distance between the preheated markings.

[0077] When placing the second sample in the tensile testing machine, the portion of the second sample wrapped with the heat-resistant material is secured using a pair of chucks from the tensile testing machine.

[0078] B4: Heat the second sample to 130°C.

[0079] In B4 above, the second sample can be heated, for example, by the heating system of a tensile testing machine. It is preferable to heat the second sample quickly.

[0080] B5: Stretch the second sample along its length at 130°C and a stretching speed of 50 mm / min, and stop stretching when the distance between the chucks reaches 60 mm.

[0081] In B5 above, the following operating conditions are set for the tensile testing machine: the tensile test stops when the distance between the chucks reaches 60mm and the chucks do not return to the original position.

[0082] B6: Remove the second sample from the tensile testing machine and place it at 23°C for 120 minutes. Then measure the thickness of the low-refractive-index layer of the second sample after elongation. Set the average thickness of the elongated low-refractive-index layer as t2.

[0083] In B6 above, the average t2 of the thickness of the low-refractive-index layer after the optical laminate is stretched is measured according to the steps (b1) and (b2) below.

[0084] (b1) A sample for film thickness measurement is prepared by exposing the cross-section of the optical laminate using a second sample that has been placed at 23°C for 120 minutes. For the sample, it is preferable to use a sample prepared from a second sample that has been placed at 23°C for 120 minutes. Figure 3 Obtained within the "S" region.

[0085] (b2) Use STEM to photograph the cross-section of the above sample at two locations. Extract the thickness of the elongated low-refractive-index layer at 5 locations from the two images, for a total of 10 thicknesses. Average the thicknesses at the 10 locations to calculate the average t2 of the elongated low-refractive-index layer thickness.

[0086] For the sample with exposed cross-section of the optical laminate described in (b1) above, it can be produced, for example, by the same steps as X1 to X2 described above.

[0087] B7: Calculate the ratio of the thickness of the elongated low-refractive-index layer to the thickness of the original low-refractive-index layer using the following formula.

[0088] The ratio (%) of the thickness of the elongated low-refractive-index layer to the thickness of the unelongated low-refractive-index layer = (t2 / t1) × 100

[0089] In condition 2, a tensile testing machine capable of temperature control is used.

[0090] In conditions 2 and 3 (described later), the atmosphere at which t1, t2, t3, and t4 are measured is 23°C and 50% relative humidity.

[0091] To easily satisfy conditions 2 and 3 described below, it is preferable to adjust the functional group equivalent of the ionizing radiation-curable resin composition forming the hard coating, or to adjust the average particle size and content of the hollow particles in the low-refractive-index layer. Detailed adjustment methods are described in the embodiments of each component.

[0092] The optical laminate preferably has a high refractive index layer between the hard coating layer and the low refractive index layer.

[0093] The optical laminate preferably further satisfies the following condition 3.

[0094] <Condition 3>

[0095] The average thickness of the high-refractive-index layer before the optical laminate is elongated is set as t3.

[0096] A third sample with a short side of 20mm and a long side of 100mm is cut from the optical laminate. After marking the third sample with 50mm intervals, it is preheated at 130°C for 2 minutes. After preheating, the third sample is quickly placed in a tensile testing machine with the chucks of the tensile testing machine having the same distance between the marks after preheating. The third sample is stretched along its long side at 130°C and a stretching speed of 50mm / min. The stretching is stopped when the distance between the chucks reaches 60mm. The third sample is removed from the tensile testing machine and placed at 23°C for 120 minutes. Then, the thickness of the high refractive index layer of the stretched third sample is measured, and the average thickness of the stretched high refractive index layer is set as t4.

[0097] The ratio of the thickness of the elongated high-refractive-index layer to the thickness of the high-refractive-index layer before elongation, calculated by the following formula, is 80% or more and 99% or less: The ratio (%) of the thickness of the elongated high refractive index layer to the thickness of the high refractive index layer before elongation = (t4 / t3) × 100.

[0098] In condition 3, a thickness variation rate of 80% or higher means that the thickness of the high-refractive-index layer will not become excessively thin after applying the optical laminate to a non-planar part. In condition 3, a thickness variation rate of 99% or lower means that the thickness variation rate of the high-refractive-index layer does not increase drastically compared to the theoretical value of 90% due to the shrinkage of the hard coating.

[0099] Therefore, by having a high refractive index layer between the hard coating layer and the low refractive index layer in the optical laminate, and satisfying condition 3, it is easier to achieve good anti-reflective properties when applied to components with non-flat shapes.

[0100] In condition 3, the thickness change rate of the high refractive index layer before and after elongation is preferably 82% or more and 97% or less, more preferably 84% or more and 95% or less, and even more preferably 86% or more and 93% or less.

[0101] For condition 3, more specifically, the measurement shall be performed according to the steps C1 to C7 below.

[0102] C1: Set the average thickness of the high-refractive-index layer before the optical laminate is stretched to t3.

[0103] In C1 above, the measurement of t3 can be performed according to the steps described above.

[0104] C2: A third sample with a short side of 20mm and a long side of 100mm is cut from the above optical laminate.

[0105] The third sample can also be used as the second sample. If the third sample is also used as the second sample, then steps C2 to C5 below can also be used as steps B2 to B5 above.

[0106] C3: After marking the third sample with 50mm intervals, preheat it at 130℃ for 2 minutes. Quickly place the preheated third sample into the tensile testing machine. The distance between the chucks of the tensile testing machine should be the same as the distance between the marks after preheating.

[0107] In C3 above, the temperature was set to 23℃ when marking the third sample with 50mm intervals.

[0108] The specific implementation method for preheating the third sample and the specific implementation method for placing the third sample in the tensile testing machine are the same as the corresponding implementation method for the second sample.

[0109] C4: Heat the third sample to 130°C.

[0110] C5: Stretch the third sample along its length at 130℃ and a stretching speed of 50mm / min, and stop stretching when the distance between the chucks reaches 60mm.

[0111] The specific implementations of C4 and C5 are the same as those of B4 and B5.

[0112] C6: Remove the third sample from the tensile testing machine and place it at 23°C for 120 minutes. Then measure the thickness of the high-refractive-index layer of the third sample after elongation. Set the average thickness of the elongated high-refractive-index layer as t4.

[0113] In this specification, by replacing “second sample” and “low refractive index layer” with “third sample” and “high refractive index layer” respectively in steps (b1) and (b2) above, the average t4 of the thickness of the high refractive index layer after the optical laminate is stretched is measured.

[0114] C7: The ratio of the thickness of the elongated high refractive index layer to the thickness of the high refractive index layer before elongation is calculated using the following formula.

[0115] The ratio (%) of the thickness of the elongated high-refractive-index layer to the thickness of the unelongated high-refractive-index layer = (t4 / t3) × 100

[0116] When an optical laminate has a high-refractive-index layer between a hard coating and a low-refractive-index layer, but condition 3 is not met, it is difficult to achieve good anti-reflective properties when applied to components with non-planar shapes. This is because, when an optical laminate has both a high-refractive-index layer and a low-refractive-index layer, the balance between the thicknesses of the high-refractive-index layer and the low-refractive-index layer becomes important.

[0117] The absolute value of the difference between the thickness ratio of condition 2 and the thickness ratio of condition 3 is preferably 3% or less, more preferably 2% or less. By making the absolute value of the difference 3% or less, a balance between the thicknesses of the high-refractive-index layer and the low-refractive-index layer can be maintained, thus making it easy to achieve good anti-reflective properties when applied to components with non-planar shapes.

[0118] In this specification, reflectance refers to the visual reflectance Y value measured based on the orthogonal reflection of the incident light when the direction perpendicular to the surface of the low-refractive-index layer of the sample made of the optical laminate is set to 0 degrees.

[0119] <Resin Substrate>

[0120] Regarding the resin substrate, a resin substrate with good light transmittance, easy stretching, and excellent moldability is preferred.

[0121] There are no particular limitations on the resin constituting the resin substrate, but to easily satisfy condition 1, a resin selected from the group consisting of carbonate resin, (meth)acrylic resin, olefin resin, and ABS resin is preferred. That is, as the resin substrate, a carbonate resin substrate, a (meth)acrylic resin substrate, an olefin resin substrate, or an ABS resin substrate is preferred. A (meth)acrylic resin substrate is more preferred because it facilitates good adhesion to the hard coating. To improve moldability, the resin substrate may also contain additives such as rubber particles.

[0122] In this specification, "(meth)acrylic acid" is a general term for "acrylic acid" and "methacrylic acid".

[0123] Examples of (meth)acrylic resins include, for example, homopolymers or copolymers of (meth)acrylates, and copolymers of (meth)acrylates with comonomers. Examples of (meth)acrylates include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and glycidyl (meth)acrylate. Examples of comonomers include, for example, vinyl acetate, methacrylonitrile, methacrylamide, styrene, methacrylic acid, itaconic acid, and maleic anhydride. (Methacryl)acrylic resins can also be fluorinated.

[0124] Specifically, examples of (meth)acrylic resins include poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, and poly(meth)acrylate, such as alkyl poly(meth)acrylate. Among these, poly(meth)acrylate is preferred.

[0125] The thickness of the resin substrate is preferably 5 μm or more and 150 μm or less, more preferably 20 μm or more and 100 μm or less, and even more preferably 30 μm or more and 50 μm or less.

[0126] By setting the thickness of the resin substrate to 5 μm or more, the optical laminate can be easily made easy to handle. By setting the thickness of the resin substrate to 150 μm or less, the optical laminate can be easily made easy to form.

[0127] The thickness of the resin substrate can be measured using a general-purpose film thickness gauge. Regarding the thickness of the resin substrate, the average value obtained from measuring any 10 points is sufficient.

[0128] To improve adhesion, physical or chemical treatments such as corona discharge can be applied to the surface of the resin substrate, or an easy-to-adhere layer can be formed.

[0129] The total light transmittance of the resin substrate according to JIS K7361-1:1997 is preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more.

[0130] Hard coating

[0131] The optical laminate disclosed herein requires a hard coating on a resin substrate. Having a hard coating readily enables the optical laminate to exhibit good scratch resistance.

[0132] The hard coating preferably contains a cured product of a curable resin composition, such as a thermosetting resin composition or an ionizing radiation-curable resin composition, as the main component. More preferably, it contains a cured product of an ionizing radiation-curable resin composition as the main component. The main component refers to 50% or more by mass of the resin component constituting the hard coating, preferably 70% or more by mass, more preferably 90% or more by mass, and even more preferably 99% or more by mass.

[0133] A thermosetting resin composition is a composition that contains at least a thermosetting resin and is a resin composition that is cured by heating.

[0134] Examples of thermosetting resins include acrylic resins, polyurethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. In thermosetting resin compositions, curing agents are added to these curing resins as needed.

[0135] The ionizing radiation-curable resin composition is a composition containing a compound having an ionizing radiation-curable functional group (hereinafter also referred to as "ionizing radiation-curable compound"). Examples of ionizing radiation-curable functional groups include olefinic unsaturated groups such as (meth)acryloyl, vinyl, and allyl, as well as epoxy and oxetyl groups. As the ionizing radiation-curable compound, a compound having an olefinic unsaturated functional group is preferred, and a compound having a (meth)acryloyl group is more preferred. A compound having a (meth)acryloyl group is preferably a (meth)acrylate-based compound.

[0136] Ionizing radiation refers to the portion of electromagnetic waves or charged particle beams that contains energy quanta capable of polymerizing or cross-linking molecules. Ultraviolet (UV) or electron (EB) beams are commonly used. In addition, electromagnetic waves such as X-rays and gamma rays, as well as charged particle beams such as alpha rays and ionizing rays can also be used.

[0137] The (meth)acrylate compounds can be monomers or oligomers. Regarding the (meth)acrylate compounds, in order to easily satisfy conditions 1 and 2 while maintaining the hardness of the hard coating, it is preferable to mix multiple (meth)acrylate compounds. For example, it is preferable to mix the (meth)acrylate compounds described in (1) to (3) below.

[0138] (1) (meth)acrylate monomers with 3 or more functional groups

[0139] (2) (meth)acrylate oligomers with an average number of 3 or more functional groups

[0140] (3) (meth)acrylate monomers with 1 or 2 functional groups

[0141] In (1) to (3) above, the number of functional groups refers to the number of (meth)acryloyl groups.

[0142] The monomers in (1) above have the effect of increasing the hardness of the hard coating. However, if there is too much of the monomers in (1) above, it is sometimes difficult to meet conditions 1 and 2, or the load at the upper yield point measured under condition 1 may become too large. If there is too little of the monomers in (1) above, the hardness of the hard coating may sometimes decrease, or the elongation under condition 1 may become too large.

[0143] The oligomer described in (2) above has the effect of easily satisfying conditions 1 and 2 while maintaining the hardness of the hard coating. It is assumed that if only the monomer described in (1) above is used as the (meth)acrylate compound, it is difficult to easily satisfy conditions 1 and 2 while maintaining the hardness of the hard coating. By including an appropriate amount of the oligomer described in (2) above, it is possible to easily satisfy conditions 1 and 2 while maintaining the hardness of the hard coating.

[0144] The monomer in (3) above has the effect of inhibiting excessive crosslinking of the hard coating. In addition, by including the monomer in (3) above as a (meth)acrylate compound, conditions 1 and 2 can be easily satisfied, and the load at the upper yield point measured under condition 1 can be easily reduced. Furthermore, the monomer in (3) above can easily achieve good adhesion to the resin substrate (especially the (meth)acrylate resin substrate). However, if there is too much of the monomer in (3) above, the hardness of the hard coating may sometimes decrease, or the elongation under condition 1 may become too large.

[0145] Based on the total amount of the ionizing radiation curable resin composition, the mass ratio of the (meth)acrylate monomer with an average functional group number of 3 or more in (1) above is preferably 1% by mass or more and 45% by mass or less, more preferably 10% by mass or more and 35% by mass or less.

[0146] Based on the total amount of the ionizing radiation curable resin composition, the mass ratio of the (meth)acrylate oligomer with an average functional group number of 3 or more in the above (2) is preferably 20% by mass or more and 85% by mass or less, more preferably 35% by mass or more and 60% by mass or less.

[0147] Based on the total amount of the ionizing radiation curable resin composition, the mass ratio of (meth)acrylate monomers with an average number of 1 or 2 functional groups in the above (3) is preferably 10% by mass or more and 50% by mass or less, more preferably 20% by mass or more and 40% by mass or less.

[0148] The mass ratio of the (meth)acrylate monomer with an average functional group number of 3 or more in (1) above to the total amount of the ionizing radiation-curable resin composition is defined as R1 (mass %). The mass ratio of the (meth)acrylate oligomer with an average functional group number of 3 or more in (2) above to the total amount of the ionizing radiation-curable resin composition is defined as R2 (mass %). The mass ratio of the (meth)acrylate monomer with a functional group number of 1 or 2 in (3) above to the total amount of the ionizing radiation-curable resin composition is defined as R3 (mass %). The average thickness of the hard coating before the optical laminate is stretched is defined as t5 (μm). In this case, it is preferable to satisfy the following conditions E1 to E3. By satisfying the following conditions E1 to E3, conditions 1 and 2 can be easily satisfied.

[0149] <Condition E1>

[0150] 55≤R1×t5≤600

[0151] <Condition E2>

[0152] 150≤R²×t⁵≤1150

[0153] <Condition E3>

[0154] 70≤R3×t5≤400

[0155] In condition E1, R1×t5 is preferably 60 or more and 310 or less, and more preferably 70 or more and 180 or less.

[0156] In condition E2, R2×t5 is preferably 150 or more and 800 or less, and more preferably 180 or more and 500 or less.

[0157] In condition E3, R3×t5 is preferably 75 or more and 350 or less, and more preferably 130 or more and 232 or less.

[0158] The functional group number of the (meth)acrylate monomer in (1) above is preferably 3 or more and 8 or less, more preferably 3 or more and 6 or less. By making the functional group number 3 or more, it is easy to achieve good scratch resistance. By making the functional group number 8 or less, it is easy to satisfy conditions 1 and 2 while maintaining the hardness of the hard coating.

[0159] Examples of (meth)acrylate monomers with three or more functions include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid modified tri(meth)acrylate.

[0160] The aforementioned (meth)acrylate monomers can also be monomers in which a portion of the molecular backbone has been modified. For example, the aforementioned (meth)acrylate monomers can also be monomers prepared by modifying a portion of the molecular backbone using ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl groups, cyclic alkyl groups, aromatic groups, bisphenols, etc.

[0161] The average number of functional groups in the (meth)acrylate oligomer of (2) above is preferably 3 or more and 8 or less, more preferably 3 or more and 6 or less. By making the average number of functional groups 3 or more, it is easy to achieve good scratch resistance. By making the average number of functional groups 8 or less, it is easy to satisfy conditions 1 and 2 while maintaining the hardness of the hard coating.

[0162] Examples of (meth)acrylate oligomers include urethane (meth)acrylates, epoxy (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, and other acrylate polymers.

[0163] For example, urethane (meth)acrylates are obtained by reacting polyols and organic diisocyanates with hydroxy (meth)acrylates.

[0164] Preferred epoxy (meth)acrylates are: (meth)acrylates obtained by reacting trifunctional or higher aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, etc., with (meth)acrylate; (meth)acrylates obtained by reacting difunctional or higher aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, etc., with polybasic acids and (meth)acrylate; and (meth)acrylates obtained by reacting difunctional or higher aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, etc., with phenols and (meth)acrylate.

[0165] The weight-average molecular weight of the (meth)acrylate oligomer in (2) above is preferably 500 or more and 3000 or less, more preferably 600 or more and 2000 or less, and even more preferably 700 or more and 1200 or less.

[0166] In this specification, the number-average molecular weight and weight-average molecular weight are average molecular weights measured by GPC analysis and converted to standard polystyrene.

[0167] The (meth)acrylate monomer with 1 or 2 functional groups in (3) above can be a (meth)acrylate monomer with 1 functional group or a (meth)acrylate monomer with 2 functional groups, or both can be used together. In order to easily satisfy conditions 1 and 2 while maintaining the hardness of the hard coating, it is preferable to contain only a (meth)acrylate monomer with 1 functional group.

[0168] Examples of difunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexanediol diacrylate.

[0169] Examples of monofunctional (meth)acrylates include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, and isobornyl methacrylate.

[0170] When the ionizing radiation curing compound is an ultraviolet curing compound, the coating liquid for hard coating preferably contains additives such as photopolymerization initiators and photopolymerization accelerators.

[0171] As a photopolymerization initiator, one or more can be selected from acetophenone, benzophenone, α-hydroxyalkyl phenyl ketone, michaelone, benzoin, benzoyl dimethyl ketal, benzoylbenzoate, α-acyl oxime ester, α-aminoalkyl phenyl ketone, thioxanone, etc.

[0172] Photopolymerization accelerators can reduce polymerization hindrance caused by air during curing, thereby accelerating the curing speed. Examples include at least one selected from isoamyl p-dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, etc.

[0173] The lower limit of the thickness of the hard coating is preferably 2.5 μm or more, more preferably 4.0 μm or more, even more preferably 5.0 μm or more, and the upper limit is preferably 13.5 μm or less, more preferably 12.0 μm or less, even more preferably 10.0 μm or less. "The thickness of the hard coating" refers to the "average t5 of the thickness of the hard coating before the optical laminate is elongated" mentioned above.

[0174] By setting the thickness of the hard coating to 2.5 μm or more, good scratch resistance can be easily achieved. By setting the thickness of the hard coating to 13.5 μm or less, condition 1 can be easily satisfied, and the load at the upper yield point measured under condition 1 can be easily reduced, and the excessive increase in internal haze can be easily suppressed.

[0175] Hard coatings may further include additives such as matting agents, leveling agents, antifouling agents, antistatic agents, antioxidants, surfactants, dispersants, UV absorbers, and light stabilizers.

[0176] Hard coatings can be formed, for example, by applying a hard coating containing the material and solvent for forming the hard coating onto a resin substrate with a coating liquid and allowing it to dry, and then irradiating it with ionizing radiation as needed.

[0177] <Low Refractive Index Layer>

[0178] The optical laminate disclosed herein requires a low refractive index layer. The low refractive index layer is preferably located on the surface of the hard coating opposite to the resin substrate.

[0179] The low-refractive-index layer preferably comprises an adhesive resin and hollow particles. More preferably, the low-refractive-index layer further comprises solid particles.

[0180] Adhesive Resins

[0181] The low-refractive-index layer preferably contains a cured product of a curable resin composition as the adhesive resin. The curable resin composition is a composition containing a curable compound such as a thermosetting resin or an ionizing radiation curable compound.

[0182] The proportion of the cured product of the curable resin composition relative to the total adhesive resin of the low refractive index layer is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 90% by mass or more, and most preferably 100% by mass.

[0183] Examples of curable resin compositions that serve as low-refractive-index layers include thermosetting resin compositions and ionizing radiation-curable resin compositions, with ionizing radiation-curable resin compositions being preferred. Specifically, the low-refractive-index layer preferably comprises a cured product of an ionizing radiation-curable resin composition as an adhesive resin.

[0184] Regarding thermosetting resin compositions or ionizing radiation-curing resin compositions, the same compositions as those exemplified in hard coatings can be listed.

[0185] To ensure good scratch resistance, the ionizing radiation-curing compound used in the low refractive index layer is preferably a (meth)acrylate compound containing 3 or more (meth)acryloyl groups.

[0186] Hollow Particles

[0187] Hollow particles are particles that have an outer shell, and the interior of the particle surrounded by the outer shell is hollow, containing air. Hollow particles are particles whose refractive index decreases proportionally to their porosity.

[0188] The outer shell of the hollow particles can be made of any inorganic or organic compound, such as silicon dioxide and magnesium fluoride, but silicon dioxide is preferred from the viewpoint of low refractive index and strength. That is, the low refractive index layer preferably contains hollow silicon dioxide particles as hollow particles.

[0189] The average particle size of the hollow particles is preferably 55.0 nm or more and 130.0 nm or less, more preferably 60.0 nm or more and 110.0 nm or less, even more preferably 65.0 nm or more and 90.0 nm or less, and even more preferably 70.0 nm or more and 80.0 nm or less.

[0190] By setting the average particle size to 55.0 nm or higher, the reflectivity of the low-refractive-index layer can be reduced, making the optical laminate more effective at preventing reflections. By setting the average particle size to 130.0 nm or lower, when the optical laminate is applied to components with non-planar shapes, it is easier to suppress uneven thickness of the low-refractive-index layer.

[0191] With the same content of hollow particles, the number of hollow particles can be increased by reducing their average particle size. Furthermore, in areas where large particles, such as hollow particles, exist, the hard coating is less prone to shrinkage. Therefore, by setting the average particle size of the hollow particles to below 90.0 nm, the shrinkage of the hard coating can be suppressed, making it easier to satisfy condition 2.

[0192] The average particle size of the hollow particles, the solid particles (described later), and the high-refractive-index particles (described later) is calculated using the following operations D1 to D3.

[0193] D1: Photograph the cross-section of the anti-reflective component using STEM. The accelerating voltage of the STEM is preferably above 10kV and below 30kV, and the magnification is preferably above 50,000x and below 100,000x.

[0194] D2: Extract all hollow particles from the low-refractive-index layer contained in an image. Then, calculate the particle size of each hollow particle. The particle size of each hollow particle refers to the distance between the two lines that maximize the distance between them when the cross-section of the hollow particle is held between any two parallel lines.

[0195] D3: Remove the hollow particles whose diameter is 10% lower than the lowest value from all hollow particles whose diameter was measured in A2. "%" represents the number of particles, rounded to the nearest whole number. The average diameter of the remaining 90% of hollow particles is taken as the average diameter of the hollow particles.

[0196] In D3 above, the reasons for excluding hollow particles with a particle size 10% below the minimum are as follows (1) and (2).

[0197] (1) Hollow particles with small particle size measurements may have been cut off at a location off the center of the hollow particle.

[0198] (2) Hollow particles with small particle size measurements may be part of the hollow particles buried in layers adjacent to low refractive index layers, such as high refractive index layers and hard coating layers.

[0199] In the aforementioned operations D1 to D3, if the extracted particles are changed to "all solid particles in a low-refractive-index layer contained in an image," the average particle size of the solid particles can be calculated. Furthermore, in the aforementioned operations D1 to D3, if the extracted particles are changed to "all high-refractive-index particles in a high-refractive-index layer contained in an image," the average particle size of the high-refractive-index particles can be calculated.

[0200] The higher the content of hollow particles, the lower the refractive index of the low-refractive-index layer. On the other hand, if the content of hollow particles relative to the adhesive resin is too high, uneven thickness of the low-refractive-index layer is likely to occur when the optical laminate is applied to parts with non-planar shapes.

[0201] Therefore, the content of hollow particles relative to 100 parts by weight of adhesive resin is preferably 100 parts by weight or more and 300 parts by weight or less, more preferably 120 parts by weight or more and 250 parts by weight or less, and even more preferably 130 parts by weight or more and 200 parts by weight or less.

[0202] Regarding hollow particles, to suppress agglomeration, it is preferable that their surface is coated with a silane coupling agent. The silane coupling agent preferably has a (meth)acryloyl group or an epoxy group, more preferably a methacryloyl group.

[0203] Hollow particles can contain two or more types of hollow particles. For example, they can contain hollow particles with different outer shell materials or hollow particles with different particle sizes.

[0204] Solid Granules

[0205] Regarding the low refractive index layer, it is preferable that it contains both hollow and solid particles. By including solid particles in addition to hollow particles, the scratch resistance of the low refractive index layer can be easily improved.

[0206] The solid particles are preferably made of inorganic compounds such as silicon dioxide and magnesium fluoride, with silicon dioxide being more preferred.

[0207] The average particle size of the solid particles is preferably smaller than that of the hollow particles. The lower limit of the average particle size of the solid particles is preferably 5 nm or more, more preferably 10 nm or more, and the upper limit is preferably 20 nm or less, more preferably 15 nm or less.

[0208] From the viewpoint of improving scratch resistance, the content of solid particles is preferably 10 parts by weight or more, and more preferably 20 parts by weight or more, relative to 100 parts by weight of adhesive resin.

[0209] On the other hand, if the content of solid particles is too high, the solid particles are prone to agglomeration, and the amount of adhesive resin covering the hollow particles is reduced, which may sometimes decrease the scratch resistance. Therefore, the content of solid particles is preferably 100 parts by weight or less relative to 100 parts by weight of adhesive resin, more preferably 50 parts by weight or less.

[0210] The lower limit of the thickness of the low refractive index layer is preferably 80 nm or more, more preferably 85 nm or more, more preferably 90 nm or more, and the upper limit is preferably 150 nm or less, more preferably 110 nm or less, more preferably 105 nm or less. "The thickness of the low refractive index layer" refers to the "average t1 of the thickness of the low refractive index layer before the optical laminate is elongated" mentioned above.

[0211] The ratio D / t1 of the thickness t1 of the low refractive index layer to the average particle size D of the hollow particles is preferably 0.55 or more and 1.00 or less, more preferably 0.65 or more and 0.95 or less, and even more preferably 0.70 or more and 0.80 or less.

[0212] By setting D / t1 to 0.55 or higher, the refractive index of the low-refractive-index layer can be easily reduced. By setting D / t1 to 1.00 or lower, when applying the optical laminate to components with non-planar shapes, it is easy to suppress the generation of uneven thickness of the low-refractive-index layer.

[0213] The lower limit of the refractive index of the low refractive index layer is preferably 1.10 or more, more preferably 1.20 or more, more preferably 1.26 or more, more preferably 1.28 or more, more preferably 1.30 or more, and the upper limit is preferably 1.48 or less, more preferably 1.45 or less, more preferably 1.40 or less, more preferably 1.38 or less, more preferably 1.35 or less.

[0214] In this specification, the refractive index of the low-refractive-index layer and the high-refractive-index layer refers to the value at a wavelength of 589.3 nm.

[0215] The low refractive index layer may further contain additives such as antistatic agents, antioxidants, surfactants, dispersants, light stabilizers, and ultraviolet absorbers.

[0216] A low-refractive-index layer can be formed by coating a low-refractive-index layer coating liquid containing the components and solvents constituting the low-refractive-index layer and drying it, and then curing it by irradiation with ionizing radiation as needed.

[0217] <Other Layers>

[0218] Optical laminates can also have other layers such as high refractive index layers and antistatic layers.

[0219] By having a high refractive index layer, the reflectivity of the optical laminate can be reduced more easily. Preferably, a high refractive index layer is present between the hard coating layer and the low refractive index layer. When the optical laminate has a high refractive index layer, it is preferable to have a resin substrate, a hard coating layer, a high refractive index layer, and a low refractive index layer in sequence.

[0220] <High Refractive Index Layer>

[0221] The high refractive index layer can be formed, for example, by a coating liquid comprising an adhesive resin composition and high refractive index particles. That is, the high refractive index layer preferably comprises an adhesive resin and high refractive index particles.

[0222] The adhesive resin of the high refractive index layer preferably comprises a cured product of a curable resin composition. The proportion of the cured product of the curable resin composition relative to the total adhesive resin of the high refractive index layer is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 90% by mass or more, and most preferably 100% by mass.

[0223] Examples of curable resin compositions for high-refractive-index layers include thermosetting resin compositions and ionizing radiation-curable resin compositions, with ionizing radiation-curable resin compositions being preferred. Regarding thermosetting resin compositions or ionizing radiation-curable resin compositions, compositions similar to those exemplified by hard coatings can be cited. The ionizing radiation-curable compound used in the high-refractive-index layer is preferably a (meth)acrylate-based compound containing three or more (meth)acryloyl groups.

[0224] Examples of high refractive index particles include antimony pentoxide, zinc oxide, titanium oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, yttrium oxide, and zirconium oxide.

[0225] The average particle size of the high refractive index particles is preferably 2 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more. From the viewpoint of suppressing whitening and transparency, the average particle size of the high refractive index particles is preferably 200 nm or less, more preferably 100 nm or less, more preferably 80 nm or less, more preferably 60 nm or less, and more preferably 30 nm or less.

[0226] Regarding the content of high refractive index particles, the lower limit is preferably 100 parts by mass or more, more preferably 150 parts by mass or more, and even more preferably 250 parts by mass or more, relative to 100 parts by mass of adhesive resin. The upper limit is preferably 500 parts by mass or less, more preferably 400 parts by mass or less, and even more preferably 350 parts by mass or less.

[0227] The lower limit of the refractive index of the high refractive index layer is preferably 1.53 or higher, more preferably 1.54 or higher, more preferably 1.55 or higher, more preferably 1.56 or higher, and the upper limit is preferably 1.85 or lower, more preferably 1.80 or lower, more preferably 1.78 or lower, more preferably 1.77 or lower.

[0228] The upper limit of the thickness of the high refractive index layer is preferably below 200 nm, more preferably below 185 nm, and even more preferably below 175 nm. The lower limit is preferably above 50 nm, more preferably above 70 nm, and even more preferably above 80 nm. "The thickness of the high refractive index layer" refers to the "average t3 of the thickness of the high refractive index layer before the optical laminate is elongated" mentioned above.

[0229] The high refractive index layer may also contain additives such as leveling agents, antistatic agents, antioxidants, surfactants, dispersants, light stabilizers, and ultraviolet absorbers.

[0230] <Pencil Hardness>

[0231] To improve scratch resistance, the pencil hardness of the front side of the optical laminate is preferably H or higher, and more preferably 2H or higher.

[0232] The front side refers to the surface of the optical laminate that has a low refractive index layer based on a hard coating.

[0233] In this specification, the pencil hardness is measured according to JIS K5600-5-4:1999 under conditions of a load of 500g and a speed of 1.4mm / second.

[0234] In addition, the pencil hardness samples were subjected to five pencil hardness tests. The hardness at which no visible abnormalities such as scratches were detected more than four times was taken as the pencil hardness value for each sample. For example, if a 2H pencil was used for five tests, and no visible abnormalities were detected four times, then the pencil hardness of that sample was 2H. Visible abnormalities did not include discoloration; scratches and dents were identified.

[0235] <Optical Properties>

[0236] The total light transmittance of the optical laminate according to JIS K7361-1:1997 is preferably 80% or more, and more preferably 85% or more.

[0237] When measuring total transmittance and haze, the light incident surface is set to the side of the resin substrate. In this specification, total transmittance refers to the average of 10 measurements.

[0238] The haze of the optical laminate (JIS K7136:2000) is preferably 1.0% or less, more preferably 0.8% or less, and even more preferably 0.7% or less. By keeping the haze below 1.0%, good image resolution can be easily achieved. There is no particular limitation on the lower limit of the haze, which is typically 0.1% or more.

[0239] The internal haze of the optical laminate is preferably 0.4% or less, more preferably 0.3% or less. By keeping the internal haze below 0.4%, it is easy to achieve good image resolution.

[0240] Internal haze can be measured using common methods, such as the following methods.

[0241] (1) A sample with the surface of the optical laminate being crushed is made by bonding a transparent sheet or the like to the surface of the optical laminate with a transparent adhesive layer.

[0242] (2) The haze of the above samples was measured according to JIS K7136:2000. The measured value was regarded as the internal haze of the optical laminate.

[0243] <Size, shape, etc.>

[0244] Optical laminates can be in the form of single sheets cut to a specified size, or in the form of rolls formed by rolling long strips into a roll. There is no particular limitation on the size of a single sheet, with a maximum diameter of 2 inches or more but less than 500 inches. "Maximum diameter" refers to the maximum length that can be drawn connecting any two points of the optical laminate. In the case of a rectangular optical laminate, the diagonal of the rectangle is the maximum diameter. In the case of a circular optical laminate, the diameter of the circle is the maximum diameter.

[0245] There are no particular limitations on the width and length of the roll, but generally, the width is between 500 mm and 3000 mm, and the length is between 500 m and 5000 m. The roll-shaped optical laminate can be cut into single sheets according to the size of the image display device, etc. When cutting, it is preferable to exclude the roll ends with unstable physical properties.

[0246] The shape of the individual pieces is not particularly limited; for example, they can be polygons such as triangles, rectangles, and pentagons, or they can be circles or random irregular shapes. More specifically, when the optical laminate is rectangular, there are no particular limitations on the aspect ratio, as long as it does not pose a problem for the display screen. For example, aspect ratios such as 1:1, 4:3, 16:10, 16:9, and 2:1 can be listed.

[0247] [Anti-reflective items]

[0248] The antireflective article disclosed herein has a component and an optical laminate of the present disclosure disposed on the component, and is configured such that the low refractive index layer side of the optical laminate faces the side opposite to the component.

[0249] Optical laminates are preferably disposed on the outermost surface of the antireflective article.

[0250] The component and the optical laminate are preferably laminated with an adhesive layer in between. The adhesive layer is preferably formed on the resin substrate side of the optical laminate or on the component before the component and the optical laminate are laminated.

[0251] As components, examples include dashboards, clocks, display cases, shop windows, and windows. Components can be transparent or opaque, and there are no particular restrictions on color.

[0252] Regarding components, components with curved surfaces or three-dimensional shapes are preferred.

[0253] As a means of stacking components and optical laminates via adhesive layers, the following (1) and (2) can be listed.

[0254] (1) A lamination method based on heating and pressurization using roller transfer printing equipment, etc., was also used.

[0255] (2) TOM molding

[0256] The TOM molding described in (2) above includes, for example, the following processes (v1) to (v5). TOM molding is described in Japanese Patent Application Publication No. 2021-178410, etc.

[0257] (v1): A process of placing a component pre-formed into a product shape in the lower vacuum chamber of a TOM molding machine having an upper vacuum chamber and a lower vacuum chamber.

[0258] (v2): A process in which the resin substrate side of the optical laminate of this disclosure is arranged between the upper vacuum chamber and the lower vacuum chamber with the lower side facing downward. Preferably, an adhesive layer is pre-formed on the resin substrate side of the optical laminate.

[0259] (v3): The process of evacuating the upper and lower vacuum chambers.

[0260] (v4): The process of heating the optical laminate while pushing the component up to the upper vacuum chamber and pressing the component onto the heated optical laminate.

[0261] (v5): A process in which the upper vacuum chamber is pressurized while the optical laminate is heated, so that the molding sheet is tightly fitted to the exposed surface of the component.

[0262] [panel]

[0263] The panel 120 of this disclosure has a display element 110 and an optical film disposed on the light emitting surface side of the display element 110. The optical film includes the optical laminate 100 of this disclosure. The panel 120 of this disclosure is configured such that the surface of the optical laminate 100 with the low refractive index layer 40 side faces the side opposite to the display element 110 (see reference). Figure 2 ).

[0264] The optical laminate is preferably disposed on the outermost surface of the panel.

[0265] The optical laminate is preferably laminated onto a surface plate or other component via an adhesive layer. The component preferably has a curved or three-dimensional shape.

[0266] Examples of display elements include liquid crystal display elements, organic EL display elements, inorganic EL display elements, plasma display elements, and LED display elements such as micro LED display elements. These display elements may also have touch panel functionality within their internal components.

[0267] The display methods of liquid crystals as liquid crystal display elements can be listed as IPS, VA, multi-domain, OCB, STN, TSTN, etc.

[0268] The panel disclosed herein can also be a panel with a touch panel. In this case, the optical laminate can be used as a component constituting the touch panel.

[0269] There is no particular limit to the size of the panel, but the maximum diameter is approximately 2 inches to 500 inches. The maximum diameter refers to the maximum length that can be connected to any two points within the panel.

[0270] [Image display device]

[0271] The image display device of this disclosure includes the panel described above.

[0272] The image display device disclosed herein preferably further comprises: a drive control unit electrically connected to the panel; and a frame housing the panel and the drive control unit, etc.

[0273] When the display element is a liquid crystal display element, the image display device of this disclosure requires a backlight. The backlight is disposed on the side of the liquid crystal display element opposite to the light emitting surface side.

[0274] There is no particular limitation on the size of the image display device, but the maximum diameter of the effective display area is between 2 inches and 500 inches.

[0275] The effective display area of ​​an image display device refers to the area capable of displaying an image. For example, in the case where the image display device has a frame surrounding the display element, the area inside the frame becomes the effective display area.

[0276] The maximum diameter of the effective display area refers to the maximum length that connects any two points within the effective display area. For example, if the effective display area is rectangular, the diagonal of the rectangle is the maximum diameter. If the effective display area is circular, the diameter of the circle is the maximum diameter.

[0277] This disclosure includes the following (1) to (15).

[0278] (1) An optical laminate having a hard coating layer and a low refractive index layer sequentially on a resin substrate, wherein, The optical laminate satisfies the following conditions 1 and 2: <Condition 1> A first sample with a short side of 20mm and a long side of 100mm is cut from the optical laminate. The first sample is placed in a tensile testing machine with a chuck spacing of 50mm. When the first sample is stretched in the long side direction at 130°C and a tensile speed of 50mm / min, the elongation at the upper yield point of the first sample is 6.5% or more. <Condition 2> Let t1 be the average thickness of the low-refractive-index layer before the optical laminate is stretched. A second sample with a short side of 20mm and a long side of 100mm was cut from the optical laminate. After marking the second sample with 50mm intervals, it was preheated at 130°C for 2 minutes. After preheating, the second sample was quickly placed in a tensile testing machine with the chucks spaced at the same distance as the preheated marks. The second sample was stretched along its long side at 130°C and a stretching speed of 50mm / min. Stretching was stopped when the chucks reached a distance of 60mm. The second sample was then removed from the tensile testing machine and placed at 23°C for 120 minutes. The thickness of the low-refractive-index layer after elongation was then measured, and the average thickness of the elongated low-refractive-index layer was defined as t2. The ratio of the thickness of the elongated low-refractive-index layer to the thickness of the unelongated low-refractive-index layer, calculated by the following formula, is 80% or more and 99% or less: The ratio (%) of the thickness of the elongated low-refractive-index layer to the thickness of the low-refractive-index layer before elongation = (t2 / t1) × 100.

[0279] (2) The optical laminate according to (1), wherein a high refractive index layer is present between the hard coating layer and the low refractive index layer.

[0280] (3) The optical laminate according to (2), wherein, The optical laminate also satisfies the following condition 3: <Condition 3> The average thickness of the high-refractive-index layer before the optical laminate is stretched is set as t3. A third sample, measuring 20mm on the short side and 100mm on the long side, was cut from the optical laminate. After marking the third sample with 50mm intervals, it was preheated at 130°C for 2 minutes. The preheated sample was then quickly placed in a tensile testing machine, with the chuck distance matching the preheated mark distance. The third sample was stretched along its long side at 130°C and a stretching speed of 50mm / min. Stretching was stopped when the chuck distance reached 60mm. The third sample was removed from the tensile testing machine and placed at 23°C for 120 minutes. The thickness of the elongated high-refractive-index layer was then measured, and the average thickness of the elongated high-refractive-index layer was defined as t4. The ratio of the thickness of the elongated high-refractive-index layer to the thickness of the high-refractive-index layer before elongation, calculated by the following formula, is 80% or more and 99% or less: The ratio (%) of the thickness of the elongated high refractive index layer to the thickness of the high refractive index layer before elongation = (t4 / t3) × 100.

[0281] (4) The optical laminate according to (3), wherein the absolute value of the difference between the ratio of the thickness of condition 2 and the ratio of the thickness of condition 3 is less than 3%.

[0282] (5) An optical laminate according to any one of (1) to (4), wherein t1 is 80 nm or more and 150 nm or less.

[0283] (6) The optical laminate according to (3) or (4), wherein t3 is 80 nm or more and 200 nm or less.

[0284] (7) An optical laminate according to any one of (1) to (6), wherein, when the average thickness of the hard coating before elongation of the optical laminate is defined as t5, t5 is 2.5 μm or more and 13.5 μm or less.

[0285] (8) An optical laminate according to any one of (1) to (7), wherein the elongation at the upper yield point of condition 1 is less than 17.0%.

[0286] (9) An optical laminate according to any one of (1) to (8), wherein the load at the upper yield point measured under condition 1 is 7.0 mN / mm. 2 the following.

[0287] (10) An optical laminate according to any one of (1) to (9), wherein the low refractive index layer comprises hollow particles having an average particle size of 55.0 nm or more and 130.0 nm or less.

[0288] (11) The optical laminate according to any one of (1) to (10), wherein the internal haze of the optical laminate is less than 0.4%.

[0289] (12) The optical laminate according to any one of (1) to (11), wherein the pencil hardness of the surface of the optical laminate, as measured according to JIS K5600-5-4:1999 under a load of 500g and a speed of 1.4mm / s, is H or higher.

[0290] (13) An antireflective article having a component and an optical laminate of any one of (1) to (12) disposed on the component, the antireflective article being configured such that the low refractive index layer side of the optical laminate faces the side opposite to the component.

[0291] (14) A panel having a display element and an optical film disposed on the light-emitting side of the display element, wherein, The panel includes an optical laminate as described in any one of (1) to (12) as the optical film, and the panel is configured such that the low refractive index layer side of the optical laminate faces the side opposite to the display element.

[0292] (15) An image display device comprising the panel described in (14).

[0293] Example

[0294] The present disclosure will now be described in more detail by way of examples, but the disclosure is not limited to these examples in any way. Unless otherwise stated, “parts” and “%” are quality bases.

[0295] 1. Measurement and Evaluation

[0296] The optical laminates of the embodiments and comparative examples were measured and evaluated as follows.

[0297] Unless otherwise specified, the atmosphere for all measurements and evaluations shall be set at 23°C and 50% relative humidity. Before each measurement and evaluation, the sample shall be exposed to the above atmosphere for 30 to 60 minutes.

[0298] For the samples used in each measurement and evaluation, the optical laminates of the examples and comparative examples can be cut to create them. After visually confirming that there are no abnormalities such as debris or scratches, the cutting location is selected from random areas.

[0299] 1-1. Measurement of elongation and load at the upper yield point

[0300] Following the steps in sections A1 to A6 of the instruction manual, the elongation (in "%) at the upper yield point of the optical laminates of the examples and comparative examples was measured. The measuring apparatus used was a testing machine manufactured by Orientec Co., Ltd., with the product number "RTC-1210A" supplemented with the option "TCLF". This testing machine is a temperature-controlled tensile testing machine.

[0301] In addition, by comparing the stress (MPa) at the upper yield point with the cross-sectional area (mm²) of the sample before tension, the method was further refined. 2 Multiply by , calculate the load at the upper yield point of the optical laminate of the embodiments and comparative examples (unit: mN / mm). 2 (”).

[0302] 1-2. Thickness change rate before and after elongation

[0303] Following the steps in B1 to B7 of the instruction manual, measure the ratio (in "%) of the thickness of the low-refractive-index layer before and after elongation of the optical laminates of the examples and comparative examples.

[0304] Following steps C1 to C7 in the main text of the instruction manual, measure the ratio (in "%) of the thickness of the high refractive index layer before and after elongation of the optical laminates of the examples and comparative examples. When measuring the ratio of the thickness of the high refractive index layer before and after elongation, the third sample is also used as the second sample. Furthermore, steps C2 to C5 are used in conjunction with steps B2 to B5. Regarding the heat-resistant tape used in B3 and C3, Nitto America's industrial tape WS-1 is used.

[0305] In the above measurements, the STEM used for measuring thicknesses t1 to t4 was a product with product number "S-4800" manufactured by Hitachi High Technology Co., Ltd. The imaging conditions were as follows.

[0306] <Filming Conditions>

[0307] Mode: TE

[0308] Accelerating voltage: 30kV

[0309] Transmitting current: 10uA

[0310] WD (Working Distance):8.0mm

[0311] Magnification: 100,000x based on High magnification mode

[0312] In the above measurements, the following materials and apparatus were used in preparing the black plate, optically transparent adhesive sheet, slicer, and sieve to expose the cross-section of the optical laminate.

[0313] • Black board (Kuraray Corporation, product name: Comaglas DFA2CG 502K (Black) series, 2mm thick)

[0314] • Optical transparent adhesive sheet (PANAC Corporation, trade name: PANACLEAN PD-S1)

[0315] • Slicer (Leica Microsystems, product name: UltraMicrotome EM UC7)

[0316] • Screen (Nisshin EM Co., Ltd., product name: screen with attached PVC film (Cat No. 651))

[0317] In the above measurements, the slicing machine's cutting conditions were set to "SPEED: 1.40 mm / s" and "FEED: 70 nm".

[0318] 1-3. Reflectance (Visual Reflectance Y-value)

[0319] Initial reflectivity

[0320] The optical laminates of the examples and comparative examples were cut into 5cm × 5cm pieces. The resin substrate side of the cut optical laminate was bonded to a black plate (Kuraray, trade name: Comaglas DFA2CG 502K (black) series, 2mm thick) measuring 5cm × 5cm in length and width, through an optically transparent adhesive sheet (PANAC, trade name: PANACLEAN PD-S1) to create a sample.

[0321] With the direction perpendicular to the low-refractive-index layer side of the sample set to 0 degrees, incident light is shone onto the sample from a direction of 5 degrees. Based on the positive reflection of the incident light, the visual reflectance Y value of the sample is measured. The measured value is taken as the "initial reflectance".

[0322] The measuring device uses a spectrophotometer (manufactured by Shimadzu Corporation, trade name: UV-2450). This measuring device measures reflectance at 0.5 nm intervals within a wavelength range of 380 nm to 780 nm, and then performs a conversion using software that adapts it to the brightness perceived by the human eye. This software is built into the measuring device. The reflectance is calculated using a light source of D65 and a viewing angle of 2 degrees.

[0323] <Reflectivity after molding>

[0324] A concave lens with a circular bottom surface (made of glass, with a bottom diameter of 50 mm, a side height of 20 mm, and a radius of curvature of 170 mm) is placed on the platform inside the lower vacuum chamber of the TOM molding machine, which has an upper vacuum chamber and a lower vacuum chamber.

[0325] Next, between the upper vacuum chamber and the lower vacuum chamber, the optical laminates of the embodiments and comparative examples are arranged with the resin substrate side facing downward (the concave lens side mentioned above), and are fixed with a clamp.

[0326] Next, the upper and lower vacuum chambers are closed to create a seal, and each vacuum chamber is evacuated (vacuum pressure: -0.1MPa (gauge pressure)).

[0327] Next, while heating the optical stack from the low refractive index layer side (heating temperature: 120°C), the stage is operated to push the concave lens up to the upper vacuum chamber and press the concave lens onto the heated optical stack.

[0328] Next, while the optical laminate is heated, the upper vacuum chamber is pressurized (compressed air pressure: 0.2 MPa (gauge pressure)) to form the optical laminate in a manner that mimics the shape of a concave lens.

[0329] Next, the upper and lower vacuum chambers are opened to the atmosphere, and after the air cools to room temperature, the concave lens and optical stack are removed. Then, the concave lens is peeled off from the formed optical stack.

[0330] (Note: Typical TOM molding involves molding two components that fit together tightly. In this embodiment, since the reflectivity of the molded optical laminate needs to be measured without the concave lens, the concave lens is not fitted tightly to the optical laminate in the above TOM molding process.)

[0331] Next, after stretching the optical laminate, which is shaped like a concave lens, to a flat state, the adhesive layer side of the laminate, which is formed by tightly bonding the adhesive layer and the black plate, is attached to the resin substrate side of the optical laminate to create a sample. The adhesive layer uses an optically clear adhesive sheet (PANAC Corporation, trade name: PANACLEAN PD-S1). The black plate used is a black plate manufactured by Kuraray Corporation (trade name: Comaglas DFA2CG 502K (black) series, thickness: 2mm).

[0332] With the direction perpendicular to the low-refractive-index layer side of the sample set to 0 degrees, incident light is shone onto the sample from a direction of 5 degrees. Based on the positive reflection of the incident light, the visual reflectance Y value of the sample is measured. The measured value is taken as the "reflectance after molding". The same apparatus used for measuring the initial reflectance is employed.

[0333] In Comparative Example 2, the reflectivity after molding could not be measured because it was not applicable to non-flat shapes.

[0334] The difference between the initial reflectivity and the reflectivity after molding (reflectivity after molding - initial reflectivity) is shown in Tables 1 and 2. A difference of less than 0.04% is considered acceptable. Initial reflectivity refers to the reflectivity before molding.

[0335] Furthermore, the ratio ((reflectance after molding - initial reflectance) / initial reflectance) × 100 is shown in Tables 1 and 2 (unit: "%)". A ratio of 35.0% or less is considered acceptable.

[0336] When the initial reflectance (%) of the above sample is defined as Y21 and the reflectance (%) of the above sample after molding is defined as Y22, it is preferable to satisfy either condition A or condition B, more preferably both conditions A and B. The difference in condition A is preferably 0.02% or less, more preferably 0.01% or less. The ratio in condition B is preferably 10.0% or less, more preferably 5.0% or less, and even more preferably 1.0% or less.

[0337] The reflectance in the above measurement refers to the visual reflectance Y value measured based on the positive reflection of the incident light when the direction perpendicular to the surface of the low refractive index layer of the sample is set to 0 degrees and the direction of the incident light is set to 5 degrees.

[0338] <Condition A>

[0339] Y22-Y21≤0.04%

[0340] <Condition B>

[0341] ((Y22-Y21) / Y21)×100≤35.0%

[0342] 1-4. Applicability relative to non-flat shapes

[0343] The suitability of the optical laminates of the embodiments and comparative examples for non-planar shapes was evaluated according to the following criteria. The evaluation was conducted visually by healthy individuals over 30 years of age with visual acuity of 1.0 or better.

[0344] A: No cracks were detected in the low-refractive-index layer.

[0345] B: Cracks can be identified in the low-refractive-index layer, but the direction of the cracks is limited to one direction.

[0346] C: Cracks can be identified in more than two directions in the low refractive index layer.

[0347] 1-5. Pencil hardness

[0348] Samples were prepared by cutting the optical laminates of the examples and comparative examples into 5cm × 10cm pieces. The pencil hardness of the low-refractive-index layer side of the above samples was measured according to JIS K5600-5-4:1999, under a load of 500g and a speed of 1.4mm / s.

[0349] The pencil hardness tester (product number: NP type pencil scratch coating hardness tester) from Toyo Seiki Manufacturing Co., Ltd. was used for the measurement. Repair tape (3M, product number "810-3-18") was used to attach both ends of the cut sample to the base of the pencil hardness tester. Five pencil hardness tests were performed, and the hardness at which no more than four scratches or other appearance abnormalities were detected was taken as the pencil hardness value for each sample. For example, if a 2H pencil was used for five tests, and no appearance abnormalities occurred in four tests, the pencil hardness of that sample was 2H. Appearance abnormalities did not include discoloration; scratches and dents were checked. A pencil hardness of H or higher is considered acceptable.

[0350] 1-6. Total transmittance (Tt), haze, internal haze

[0351] The optical laminates of the examples and comparative examples were cut into 10cm × 10cm pieces to prepare samples for measurement. Using a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute), the total transmittance of each sample according to JIS K7361-1:1997 and the haze according to JIS K7136:2000 were measured under the following conditions.

[0352] Next, an 80 μm thick TAC film (Fujifilm, TD80UL) was attached to the surface of the low-refractive-index layer side of the optical laminate of the examples and comparative examples using a transparent adhesive (PANAC, PD-S1, 25 μm thick). This crushed the uneven shape and flattened it, creating a sample that eliminated the influence of surface shape on haze. The haze of the sample was measured according to JIS K7136:2000, and the obtained value was taken as the internal haze.

[0353] <Conditions>

[0354] To stabilize the light source, the device was powered on and allowed to stand for at least 15 minutes beforehand. Then, the sample was placed at the inlet opening for calibration, leaving nothing in place. Next, the sample was placed at the inlet opening, and the total transmittance and haze were measured. The light incident surface during measurement was the substrate side.

[0355] 2. Preparation of coating liquid for hard coating

[0356] <Coating liquid for hard coating in Example 1>

[0357] The following materials are mixed and stirred to obtain the coating liquid for hard coating of Example 1.

[0358] 49 parts by weight of urethane acrylate oligomer

[0359] (Average number of functional groups: 3; weight average molecular weight: 700–1200)

[0360] 18 parts by weight of pentaerythritol triacrylate

[0361] (Manufactured by Nippon Kayaku Co., Ltd., trade name: PET-30)

[0362] · 33 parts by weight of monofunctional acrylic monomer

[0363] (Made by Kyoei Chemicals, trade name: Light Acrylate PO-A)

[0364] · 5 parts by weight of photopolymerization initiator

[0365] (Made by IGM Resins, product name: Omnirad184)

[0366] · Leveling agent 0.5 parts by weight

[0367] (Made by DIC Corporation, Product Name: F-568)

[0368] • Diluent

[0369] (A 1:1 mixture of methyl ethyl ketone and methyl isobutyl ketone in a solvent. Prepared with a solid content of 30% by mass.)

[0370] <Coating solutions for hard coatings in Examples 2-9 and Comparative Examples 1-3>

[0371] Except for changing the formulation of the adhesive resin composition to the formulations in Tables 1 and 2, the hard coating liquids of Examples 2 to 9 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1.

[0372] 3. Preparation of coating solution for high refractive index layers

[0373] <Coating liquid for high refractive index layers in Examples 1-9 and Comparative Examples 2-3>

[0374] The following materials were mixed and stirred to obtain the coating liquid for high refractive index layers in Examples 1-9 and Comparative Examples 2-3.

[0375] · 100 parts by weight of polyurethane acrylate

[0376] (Kyoeisha Chemical Co., Ltd., product name "UA-306H")

[0377] 130 parts by weight of zirconium oxide particles

[0378] (Average particle size: 20nm)

[0379] · 5 parts by weight of photopolymerization initiator

[0380] (Manufactured by IGM Resins, product name: Omnirad184)

[0381] · Leveling agent 0.4 parts by weight

[0382] (BYK Corporation, Product Name: BYK-331)

[0383] 7000 parts by weight of methyl isobutyl ketone

[0384] <Coating liquid for high refractive index layer in Comparative Example 1>

[0385] The zirconia particles with an average particle size of 20 nm were changed to zirconia particles with an average particle size of 40 nm. Otherwise, the high refractive index layer coating liquid of Comparative Example 1 was obtained in the same manner as in Example 1.

[0386] 4. Preparation of coating solution for low refractive index layer

[0387] <Coating liquid for the low refractive index layer in Example 1>

[0388] The following materials are mixed and stirred to obtain the coating liquid for the low refractive index layer of Example 1.

[0389] • 100 parts by weight of 6-functional acrylate monomer (converted from solid content)

[0390] (DPHA)

[0391] 130 parts by weight of hollow silica particles

[0392] (Hollow silica particles with an average particle size of 75 nm, surface-treated with a silane coupling agent containing methacrylyl groups)

[0393] 10 parts by weight of solid silica granules

[0394] (Average particle size is 12nm)

[0395] · 0.1 parts by weight of leveling agent

[0396] (Dai Nippon Seika Co., Ltd., Product Name: SEIKA-BEAM 1028 (MB))

[0397] · 5 parts by weight of photopolymerization initiator

[0398] (IGM Resins, product name: Omnirad127)

[0399] 1700 parts by weight of methyl ethyl ketone

[0400] 4300 parts by weight of methyl isobutyl ketone

[0401] ·Propylene glycol monomethyl ether acetate 2500 parts by weight

[0402] <Coating liquids for low refractive index layers in Examples 2-10 and Comparative Examples 1-3>

[0403] Except that the average particle size of the hollow silica particles was set to the average particle size recorded in Tables 1 and 2, the coating solutions for the low refractive index layer of Examples 2 to 10 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1 (the average particle size of the hollow silica in Example 4 was 60 nm, and the average particle size of the hollow silica in Example 9, Comparative Examples 1 and 3 was 100 nm). In addition, the coating solutions for the low refractive index layer of Examples 8 and 10 contained 100 parts by mass of hollow silica particles with an average particle size of 75 nm and 30 parts by mass of hollow silica particles with an average particle size of 100 nm.

[0404] 5. Fabrication of optical laminates

[0405] [Example 1]

[0406] After applying the hard coating solution of Example 1 to a 40 μm thick polymethyl methacrylate substrate (Tg = 125 °C), it was dried at 70 °C for 1 minute to allow the solvent to evaporate. Next, it was irradiated with a cumulative light intensity of 100 mJ / cm² in a nitrogen atmosphere. 2 The ultraviolet light is used to form a hard coating with a dry thickness of 7.0 μm.

[0407] Next, after applying the high refractive index coating liquid of Example 1 onto the hard coating layer, it was dried at 70°C for 1 minute to allow the solvent to evaporate. Then, under a nitrogen atmosphere, at 100 mJ / cm²... 2 The accumulated light is irradiated with ultraviolet light, thereby forming a dry, high-refractive-index layer with a thickness of 155 nm.

[0408] Next, after coating the high-refractive-index layer with the coating liquid for the low-refractive-index layer of Example 1, it was dried at 40°C for 60 seconds to allow the solvent to evaporate. Then, under a nitrogen atmosphere, it was dried at 200 mJ / cm². 2 The accumulated light is irradiated with ultraviolet light to form a dry, low-refractive-index layer with a thickness of 106 nm, thus obtaining the optical laminate of Example 1.

[0409] [Examples 2-10], [Comparative Examples 1 and 3]

[0410] The coating liquid for the hard coating layer, the coating liquid for the high refractive index layer, and the coating liquid for the low refractive index layer were changed to the coating liquids used in Examples 2-10 and Comparative Examples 1 and 3, respectively. Furthermore, the thicknesses of the hard coating layer, the high refractive index layer, and the low refractive index layer were changed to the values ​​in Tables 1 and 2. Otherwise, the optical laminates of Examples 2-10 and Comparative Examples 1 and 3 were obtained in the same manner as in Example 1.

[0411] [Comparative Example 2]

[0412] The resin substrate was changed to a triacetyl cellulose film with a thickness of 80 μm (a product manufactured by Fujifilm under the trade name "FUJITAC"). The coating liquid for the hard coating layer, the coating liquid for the high refractive index layer, and the coating liquid for the low refractive index layer were changed to the coating liquid used in Comparative Example 2. Furthermore, the thicknesses of the hard coating layer, the high refractive index layer, and the low refractive index layer were changed to the values ​​in Table 2. Otherwise, the optical laminate of Comparative Example 2 was obtained in the same manner as in Example 1.

[0413]

[0414] In Tables 1 and 2, “PETA” represents pentaerythritol triacrylate, “PMMA” represents polymethyl methacrylate film, and “TAC” represents triacetyl cellulose film.

[0415] In Tables 1 and 2, “R1” represents the mass ratio of pentaerythritol triacrylate relative to the total amount of the resin composition, “R2” represents the mass ratio of urethane acrylate oligomer relative to the total amount of the resin composition, and “R3” represents the mass ratio of monofunctional acrylic monomer relative to the total amount of the resin composition. The unit for R1 to R3 is “mass%”.

[0416] The results in Tables 1 and 2 confirm that the optical laminate of the embodiment provides good antireflective properties even when applied to components with non-flat shapes.

[0417] Label Explanation

[0418] 10: Resin substrate; 20: Hard coating; 30: High refractive index layer; 40: Low refractive index layer; 100: Optical laminate; 110: Display element; 120: Panel.

Claims

1. An optical laminate having a hard coating layer and a low refractive index layer sequentially formed on a resin substrate, wherein, The optical laminate satisfies the following conditions 1 and 2: <Condition 1> A first sample with a short side of 20mm and a long side of 100mm is cut from the optical laminate. The first sample is placed in a tensile testing machine with a chuck spacing of 50mm. When the first sample is stretched in the long side direction at 130°C and a tensile speed of 50mm / min, the elongation at the upper yield point of the first sample is 6.5% or more. <Condition 2> Let t1 be the average thickness of the low-refractive-index layer before the optical laminate is stretched. A second sample with a short side of 20mm and a long side of 100mm was cut from the optical laminate. After marking the second sample with 50mm intervals, it was preheated at 130°C for 2 minutes. After preheating, the second sample was quickly placed in a tensile testing machine with the chucks spaced at the same distance as the preheated marks. The second sample was stretched along its long side at 130°C and a stretching speed of 50mm / min. Stretching was stopped when the chucks reached a distance of 60mm. The second sample was then removed from the tensile testing machine and placed at 23°C for 120 minutes. The thickness of the low-refractive-index layer after elongation was then measured, and the average thickness of the elongated low-refractive-index layer was defined as t2. The ratio of the thickness of the elongated low-refractive-index layer to the thickness of the unelongated low-refractive-index layer, calculated by the following formula, is 80% or more and 99% or less: The ratio (%) of the thickness of the elongated low-refractive-index layer to the thickness of the low-refractive-index layer before elongation = (t2 / t1) × 100.

2. The optical laminate according to claim 1, wherein, A high refractive index layer is present between the hard coating layer and the low refractive index layer.

3. The optical laminate according to claim 2, wherein, The optical laminate also satisfies the following condition 3: <Condition 3> The average thickness of the high-refractive-index layer before the optical laminate is stretched is set as t3. A third sample, measuring 20mm on the short side and 100mm on the long side, was cut from the optical laminate. After marking the third sample with 50mm intervals, it was preheated at 130°C for 2 minutes. The preheated sample was then quickly placed in a tensile testing machine, with the chuck distance matching the preheated mark distance. The third sample was stretched along its long side at 130°C and a stretching speed of 50mm / min. Stretching was stopped when the chuck distance reached 60mm. The third sample was removed from the tensile testing machine and placed at 23°C for 120 minutes. The thickness of the elongated high-refractive-index layer was then measured, and the average thickness of the elongated high-refractive-index layer was defined as t4. The ratio of the thickness of the elongated high-refractive-index layer to the thickness of the high-refractive-index layer before elongation, calculated by the following formula, is 80% or more and 99% or less: The ratio (%) of the thickness of the elongated high refractive index layer to the thickness of the high refractive index layer before elongation = (t4 / t3) × 100.

4. The optical laminate according to claim 3, wherein, The absolute value of the difference between the thickness ratio of condition 2 and the thickness ratio of condition 3 is less than 3%.

5. The optical laminate according to claim 1, wherein, t1 is above 80nm and below 150nm.

6. The optical laminate according to claim 3, wherein, t3 is above 80nm and below 200nm.

7. The optical laminate according to claim 1, wherein, When the average thickness of the hard coating prior to elongating the optical laminate is defined as t5, t5 is greater than 2.5 μm and less than 13.5 μm.

8. The optical laminate according to claim 1, wherein, The elongation at the upper yield point under condition 1 is less than 17.0%.

9. The optical laminate according to claim 1, wherein, The load at the upper yield point measured under condition 1 was 7.0 mN / mm. 2 the following.

10. The optical laminate according to claim 1, wherein, The low refractive index layer comprises hollow particles with an average particle size of 55.0 nm or more and 130.0 nm or less.

11. The optical laminate according to claim 1, wherein, The internal haze of the optical laminate is below 0.4%.

12. The optical laminate according to claim 1, wherein, According to JIS K5600-5-4:1999, the pencil hardness of the surface of the optical laminate, measured under a load of 500g and a speed of 1.4mm / s, is H or higher.

13. An antireflective article having a component and an optical laminate of any one of claims 1 to 12 disposed on the component, the antireflective article being configured such that the low-refractive-index layer side of the optical laminate faces the side opposite to the component.

14. A panel having a display element and an optical film disposed on the light-emitting surface side of the display element, wherein, The panel comprises an optical laminate as described in any one of claims 1 to 12 as the optical film, and the panel is configured such that the low refractive index layer side of the optical laminate faces the side opposite to the display element.

15. An image display device comprising the panel of claim 14.

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