Resin layer, optical film and image display device

Abstract

To provide a resin layer having excellent foldability and impact resistance, an optical film comprising the resin layer, and an image display device.SOLUTION: According to one aspect of the present invention, a resin layer 10 is used in an image display device and has optical transparency, where the resin layer 10 is divided into three equal regions in a thickness direction D1 of the resin layer 10, which are successively divided into a first region 10C, a second region 10D, and a third region 10E from a first surface 10A of the resin layer 10 toward a second surface 10B opposite the first surface 10A, and the resin layer 10 satisfies the relation of d1<d2<d3 when an indentation test is performed in which a Berkovich indenter is pressed with a constant load into each of the first region 10C, the second region 10D, and the third region 10E in a cross section of the resin layer 10 in the thickness direction D1, where a displacement amount in the first region 10C is d1, a displacement amount in the second region 10D is d2, and a displacement amount in the third region 10E is d3.SELECTED DRAWING: Figure 2

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This application is a direct sequel to the prior Japanese application No. 2019-37342 (filed March 2019) Patent Application No. 2019-68027 (Application date: March 29, 2019), and Patent Application No. 2 This application benefits from the priority claim of No. 019-177178 (filed on September 27, 2019). No. 6,399,633, the entire disclosure of which is incorporated herein by reference. [Technical field]

[0002] The present invention relates to a resin layer, an optical film, and an image display device. [Background technology]

[0003] Image display devices such as smartphones and tablet terminals have been known for some time. In recent years, foldable image display devices have been developed. The terminals of the mobile phone are covered with cover glass. Although glass is generally excellent in hardness, Since it is difficult to bend, if a cover glass is used for an image display device, it may break when you try to fold it. For this reason, the cover glass is not included in the foldable image display device. Alternatively, a foldable optical film comprising a bendable resin substrate and a hard coat layer may be used. Alternatively, the use of foldable optical films made of resin has been considered (for example, (See Patent Documents 1 and 2.) In addition, Patent Document 2 describes that the hard coat layer has a function of preventing external light reflection and glare. For inhibition, the inclusion of organic particles is disclosed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-125063 A [Patent Document 2] International Publication No. 2017 / 14198 Summary of the Invention [Problem to be solved by the invention]

[0005] In the optical film used in such a foldable image display device, In addition to being foldable, the surface of the optical film may be subjected to impacts, so impact resistance is also required. Here, when an impact is applied to the surface side of the optical film, The surface of the image display device is recessed, and the member ( For this reason, if an impact is applied to the surface of the optical film, Impact resistance that does not dent the surface of the optical film, or impact resistance that does not dent the surface of the optical film When a pressure is applied to the optical film, the surface of the optical film does not become depressed, and the optical film in the image display device Rather, impact resistance is required so that the internal components (e.g. polarizing plates) are not damaged. do.

[0006] Furthermore, when such an optical film is held in a folded state, the bending portion of the optical film Until now, optical films with good folding properties have not been available. However, no consideration has been given to folding habits. This is an index that evaluates whether the product will crack or break when folded, and is therefore completely different from whether the product will develop a crease. For this reason, even if the optical film has good folding properties, there is a risk of the film developing a fold crease. do.

[0007] In addition, since the foldable optical film is used in place of a cover glass, It may be pressed by a finger. However, it is softer than the cover glass, so it is easy to press. Occasionally it may become indented and leave marks (pressure marks).

[0008] Currently, we are considering adding organic particles to the hard coat layer to make the pressure marks less noticeable. It has been investigated whether the addition of organic particles causes the particles to migrate from the interface between the organic particles and the binder resin during folding. Cracks may occur and the optical film may break.

[0009] The present invention has been made to solve the above problems. Layer having good elasticity and impact resistance, optical film and image display device including same - Patents.com It is also an object of the present invention to provide a folding paper that is difficult to fold and has good impact resistance. An object of the present invention is to provide a foldable optical film and an image display device including the same. Furthermore, a foldable optical film in which pressure marks are not easily noticeable and which is not easily cracked when folded, Another object of the present invention is to provide an image display device equipped with the above. [Means for solving the problem]

[0010] The present invention includes the following inventions. [1] A resin layer used in an image display device and having optical transparency, comprising: The resin layer is divided into three equal parts in the thickness direction, and a second surface of the resin layer is formed on the opposite side from the first surface. The resin layer is divided into a first region, a second region, and a third region in the thickness direction. A bar is applied to the first area, the second area, and the third area with a constant load. The displacement in the first region when the indentation test is performed by pressing the pitch indenter is d1, When the displacement amount in the second region is d2 and the displacement amount in the third region is d3, , a resin layer satisfying the relationship of d1 < d2 < d3.

[0011] [2] The ratio of the displacement amount d1 to the displacement amount d3 is 0.85 or less, as described in the above [1]. The resin layer according to the above.

[0012] [3] The displacement amounts d1 to d3 are each 200 nm or more and 1000 nm or less, as described in the above [1] or [2] The resin layer according to the above.

[0013] [4] The film thickness is 20 μm or more and 150 μm or less, any one of the above [1] to [3] The resin layer according to the above item.

[0014] [5] An optical film having a foldable laminated structure, comprising at least the resin layer according to any one of the above [1] to [4]. The optical film according to the above.

[0015] [6] A functional layer provided on either one of the first surface and the second surface of the resin layer. The optical film according to the above [5], further comprising the above.

[0016] [7] A resin substrate provided on either one of the first surface and the second surface of the resin layer. The optical film according to the above [5] or [6], further comprising the above.

[0017] [8] A foldable light-transmissive optical film, comprising a resin substrate and a resin layer provided on the first surface side of the resin substrate, wherein the thickness of the resin substrate is 20 μm or less, and the film thickness of the resin layer is 50 μm or more, and the ratio of the film thickness of the resin layer to the thickness of the resin substrate is 4.0 or more and 12.0 or less. When a pressing test is performed by pressing a Berkovich indenter with a maximum load of 200 μN in the cross-section in the thickness direction of the resin substrate, the deformation of the resin substrate is as follows: The thickness of the resin layer is 50 nm or more and 250 nm or less, and When a push-in test is performed, the displacement of the resin layer is 200 nm or more and 1500 nm or less. Optical film.

[0018] [9] The resin substrate is a polyimide resin, a polyamide resin, or a polyamideimide. The optical film according to the above [8], comprising at least one of a polyimide-based resin and a polystyrene-based resin.

[0019]

[10] A hard coat layer provided on a second surface side opposite to the first surface of the resin substrate. The optical film according to the above [8] or [9] further comprises:

[0020]

[11] A foldable optical film for use in an image display device, comprising: a resin substrate; a resin layer provided on one surface side of the resin substrate and containing organic particles; The surface of the resin layer is an uneven surface, and the organic particles are arranged so as to divide the resin layer in two equal portions in the thickness direction of the resin layer. The optical film is provided with a center line dividing the optical fiber, the center line being biased toward the resin substrate.

[0021]

[12] The resin substrate is a polyimide resin, a polyamideimide resin, a polyamide resin. The optical film described in the above

[0011] , which contains one or more resins selected from the group consisting of polyester resins and polyester-based resins.

[0022]

[13] The optical film described in

[11] or

[0012] above, wherein the resin layer has a thickness of 2 μm or more and 15 μm or less.

[0023]

[14] The indentation hardness of the lower part of the resin layer is greater than the indentation hardness of the upper part of the resin layer.

[11] to

[13] above, Film.

[0024]

[15] The resin layer comprises a first resin layer and a second resin layer provided on the surface side of the first resin layer. The optical film according to any one of

[11] to

[0014] above, further comprising a first resin layer and a second resin layer, the first resin layer containing the organic particles.

[0025]

[16] In the optical film, the distance between the opposing sides of the optical film is 10 mm. When the test was repeated 100,000 times, no cracks or breaks occurred. The optical film according to any one of the above [5] to

[15] .

[0026]

[17] A display element, and the above-mentioned [1] to [4] arranged on the viewer side of the display element. or the resin layer according to any one of the above [5] to

[16] . An image display device comprising: an optical film.

[0027]

[18] The image display device according to

[17] above, wherein the display element is an organic light-emitting diode element. display device. Effect of the Invention

[0028] According to the first aspect of the present invention, a resin layer having good foldability and good impact resistance, According to a second aspect of the present invention, an optical film and an image display device including the optical film and the image display device can be provided. Foldable optical film that is unlikely to develop a crease and has good impact resistance, and the same According to the third aspect of the present invention, it is possible to provide an image display device comprising: The present invention provides a foldable optical film that is difficult to break when folded, and an image display device including the same. Can be provided. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic diagram of a resin layer according to the first embodiment. [Diagram 2] FIG. 2 is a partially enlarged view of the resin layer in FIG. [Diagram 3] FIG. 3 is a schematic diagram of the optical film according to the first embodiment. [Figure 4] 4(A) to 4(C) are schematic diagrams showing the state of the continuous folding test. [Diagram 5] FIG. 5 is a schematic diagram of another optical film according to the first embodiment. [Figure 6] FIG. 6 is a schematic configuration diagram of the image display device according to the first embodiment. [Figure 7] FIG. 7 is a schematic diagram of the optical film according to the second embodiment. [Figure 8] 8(A) and 8(B) are schematic diagrams showing the state of the folding static test. [Figure 9] FIG. 9 is a schematic diagram of an optical film according to the third embodiment. [Figure 10] FIG. 10 is a partially enlarged view of the optical film of FIG. [Figure 11] FIG. 11 is a schematic diagram of another optical film according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] [First embodiment] The resin layer, the optical film, the optical film and the image display according to the first embodiment of the present invention will be described below. The display device will be described with reference to the drawings. Terms such as "port" and "port" are not to be distinguished from one another solely on the basis of differences in name. Therefore, for example, the term "film" is used to include materials also called sheets. FIG. 1 is a schematic diagram of a resin layer according to this embodiment, and FIG. 2 is a partially enlarged view of the resin layer in FIG. 3 is a schematic diagram of the optical film according to the present embodiment. FIG. 5 is a diagram showing a schematic diagram of a test state, and is a schematic structure of another optical film according to an embodiment. This is a schematic diagram.

[0031] <<<Resin layer>>> The resin layer 10 shown in FIG. 1 is used in an image display device and has optical transparency. In the present embodiment, the term "resin layer" refers to a layer having a single layer structure containing a resin. The resin layer 10 is made of a resin having optical transparency and has impact absorbing properties. However, it is preferable that the optical film 30, 50 having a laminated structure is used as the optical film 30, 50. A release film may be attached to the resin layer 10. "Light transmittance" in this context means the property of transmitting light. For example, a total light transmittance of 50% or more, preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more. The term "light-transmitting" does not necessarily mean that the material is transparent, but may also be semi-transparent. .

[0032] As shown in FIG. 2, the resin layer 10 is divided into three equal parts in a thickness direction D1 of the resin layer 10. The resin layer 10 is divided into two portions, one at a time, and the other at a time. The resin layer 10 is formed in a thickness direction D1 by dividing the first region 10C, the second region 10D, and the third region 10E. In the cross section of 10, the first region 10C, the second region 10D, and the third region 10E are each In the first region 10C, when a Berkovich indenter is pressed into the indentation test with a constant load The displacement amount in the second region 10D is d1, the displacement amount in the third region 10E is d2, and When the position is d3, the following relational expression (1) is satisfied. Since it is softer and more viscous than the functional layer (hard coat layer) and resin substrate, nano- The method of measuring the indentation hardness or Martens hardness is not suitable. Therefore, the amount of displacement is used as an index of hardness. d1 <d2<d3 …(1)

[0033] The displacements d1 to d3 were measured using a nanoindenter (e.g., a Bruker Using a TI950 TriboIndenter, the following can be done: Specifically, the resin layer cut into 1 mm × 10 mm pieces is embedded in embedding resin. A block was prepared, and a uniform section without holes was cut from this block using a general sectioning method. A slice having a thickness of 70 nm to 100 nm is cut out. The reason for cutting out the sections below 0 nm was that the remaining blocks were cut out at the time of measurement. By cutting out a piece of this thickness, the flatness of the cross section of the remaining block is ensured. If the flatness of the remaining blocks is poor, the measurement accuracy may be deteriorated. For example, the Leica Microsystems Ultramicroscopy was used to prepare the sections. A chromatome such as EM UC7 can be used. The remaining blocks are used as measurement samples. In the cross section obtained by cutting out the above-mentioned slice, the following measurement conditions were used: The indenter may be a Berkovich indenter (a triangular pyramid, e.g., Bruker The TI-0039 (manufactured by TI-0039) was applied to the center of the cross section of the first region of the resin layer in the thickness direction for 40 seconds. A load of 200 μN is applied vertically, and the displacement (pressure depth) d1 is measured. In this case, the Berkovich indenter is placed on the resin layer in the first region in order to avoid the influence of the side edge of the resin layer. The layer is pressed into the area 500 nm or more away from each end of the layer toward the center of the resin layer. The amount of displacement shall be the arithmetic average of the values ​​obtained by measuring at 10 points. If any measurements are found to deviate by more than ±20% from the mean surgical value, they will be excluded and remeasured. The measurements are to be carried out if there are any measurements that deviate from the arithmetic mean by ±20% or more. Whether or not the measured value is A and the arithmetic mean value is B is determined by (AB) / B×100. The judgment shall be made based on whether the value (%) obtained by the above test is within ±20%. The displacement amounts of the second and third regions are measured in the same manner as the displacement amount of the first region. (Measurement conditions) Control method: Load control (maximum load 200μN) Lift amount: 0nm Preload: 0.5μN ·Loading speed: 5μN / sec Maximum load hold time: 5 seconds ·Unloading speed: 5μN / sec ·Temperature: 23±5℃ Relative humidity: 30%~70%

[0034] It is preferable that the ratio (d1 / d3) of the displacement amount d1 to the displacement amount d3 is 0.85 or less. If d1 / d3 is 0.85 or less, excellent foldability and impact resistance are achieved. In addition, the upper limit of d1 / d3 is 0.82 or less, or 0.80 or less. It is more preferable that the lower limit is 0.40 or more, and 0.05 or more, from the viewpoint of easily suppressing the occurrence of wrinkles when bent. It is preferably 0.50 or greater, or 0.60 or greater.

[0035] The ratio of the displacement d1 to the displacement d2 (d1 / d2) is 0.70 or more and 0.99 or less. If d1 / d2 is 0.70 or more, the occurrence of wrinkles during bending is suppressed. If d1 / d2 is 0.99 or less, the material will have excellent foldability and impact resistance. The lower limit of d1 / d2 is 0.75 or more, 0.80 or more, or It is more preferable that the ratio is 0.85 or more, and the upper limit is 0.95 or less, 0.92 or less, or It is more preferable that the ratio is 0.90 or less.

[0036] The ratio of the displacement d2 to the displacement d3 (d2 / d3) is 0.70 or more and 0.99 or less. If d2 / d3 is 0.70 or more, the occurrence of wrinkles during bending is suppressed. If d2 / d3 is 0.99 or less, the material will have excellent folding properties, impact resistance, and The lower limit of d2 / d3 is 0.75 or more, 0.80 or more, or It is more preferable that the ratio is 0.85 or more, and the upper limit is 0.95 or less, 0.92 or less, or It is more preferable that the ratio is 0.90 or less.

[0037] It is preferable that the displacement amounts d1 to d3 are each 1000 nm or less. If d3 is 1000 nm or less, the resin layer 10 has sufficient hardness and excellent impact resistance. The upper limits of the displacements d1 to d3 are 900 nμm or less and 80 The lower limit is preferably 0 nm or less, or 700 nm or less. From the viewpoint of ensuring foldability, the thickness is set to 200 nm or more, 300 nm or more, or 350 nm or more, respectively. It is more preferable that the thickness is 1 nm or more.

[0038] The total light transmittance of the resin layer 10 is preferably 85% or more. If the transmittance is 85% or more, sufficient image visibility is achieved when the resin layer 10 is used in a mobile terminal. The resin layer 10 has a total light transmittance of 87% or more, or 90% or more. It is more preferable that there is.

[0039] The above total light transmittance is measured under conditions of temperature 23±5℃ and relative humidity 30% to 70%. , Haze meter (for example, product name "HM-150", manufactured by Murakami Color Research Laboratory Co., Ltd.) It can be measured by a method conforming to JIS K7361-1:1997 using The total light transmittance was measured by cutting the resin layer into a size of 50 mm x 100 mm, The resin layer is placed on the surface without any marks or wrinkles, fingerprints, dust, etc., and each resin layer is measured three times. The arithmetic mean value of the measured values ​​is used. This does not mean measuring a location three times, but rather measuring three different locations. In the oil layer 10, the first surface 10A and the second surface 10B are flat when visually observed, and the thickness of the film is not uniform. The variation is within the range of ±10%. By measuring the light transmittance, the average value of the total light transmittance over the entire surface of the resin layer can be obtained. The variation in total light transmittance is due to the measurement object being a long object of 1m x 3000m. Even if the size of a 5-inch smartphone is small, the error is within ±10%. If the resin layer cannot be cut to the above size, for example, the HM-150 is used for measurement. Since the inlet opening is 20 mmφ, the sample size must be 21 mm or more in diameter. Therefore, the resin layer may be cut into a size of 22 mm x 22 mm or more. If the size of the resin layer is small, move it little by little as long as the light spot does not move out of focus. The measurement points are set to three by changing the angle, etc.

[0040] The haze value (total haze value) of the resin layer 10 is preferably 3.0% or less. If the haze value is 3.0% or less, when the resin layer is used in a mobile terminal, The above haze value can be set to 2.0% or less, 1.5% or less, 1.0% or less, or It is more preferable that the content is 0.5% or less.

[0041] The above haze values ​​are measured under conditions of temperature 23±5℃ and relative humidity 30% to 70%. Using a color meter (for example, product name "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd.) It can be measured by a method conforming to JIS K7136:2000. The haze value is measured in the same manner as in the measurement of the total light transmittance.

[0042] The thickness of the resin layer 10 is preferably 20 μm or more and 150 μm or less. If the thickness of the layer 10 is 20 μm or more, excellent impact resistance can be obtained. If the thickness of the resin layer 10 is 150 μm or less, the resin layer 1 The lower limit of the thickness of the resin layer 10 is 40 μm or more, The upper limit of the resin layer 10 is preferably set to 50 μm or more, which is suitable for making the resin layer 10 thinner. From the viewpoint of good workability, the thickness is set to 120 μm or less, 100 μm or less, 80 μm or less, or It is more preferable that the thickness is 60 μm or less.

[0043] The thickness of the resin layer 10 was measured by photographing a cross section of the resin layer 10 using a scanning electron microscope (SEM). The thickness of the resin layer 10 was measured at 10 points in the cross-sectional image. The arithmetic mean value is used.

[0044] The specific method for taking cross-sectional photographs is described below. First, cut the specimen into pieces measuring 1 mm x 10 mm. The extracted resin layer was embedded in an embedding resin to create a block, and a general sample was extracted from this block. By using a simple section preparation method, uniform sections with no holes or other defects and a thickness of 70 nm to 100 nm are cut. For example, an Ultramicroscope (Leica Microsystems) was used to prepare the sections. A chromatome such as EM UC7 can be used. The measurement sample is then analyzed using a scanning transmission electron microscope (STEM). The scanning transmission electron microscope (STEM) used was that of Hitachi, Ltd. One example is the S-4800 manufactured by Ito Technologies. When taking the image, the detector was set to "SE", the acceleration voltage to "5 kV", and the emission current to "10 The cross-section is observed at a magnification of 1 μA. The focus is adjusted to obtain the best contrast and magnification. While observing the brightness to see if each layer can be distinguished, examine the image at a magnification of 100 to 100,000 times, preferably 500 to 100,000 times. The concentration is appropriately adjusted to 50,000 times, and more preferably 1,000 to 10,000 times. When taking cross-sectional photographs using the objective lens, set the beam monitor aperture to "3" and You can also set the aperture to "3" and the WD to "8 mm". Measure the thickness of the resin layer. In this case, when observing the cross section, the interfacial contrast between the resin layer and other layers (e.g., embedding resin) was observed. It is important to be able to observe the interface as clearly as possible. If it is difficult to see, staining with osmium tetroxide, ruthenium tetroxide, phosphotungstic acid, etc. The interface between the organic layers can be easily seen by performing the dyeing process. The contrast of the surface may be difficult to see at high magnification. In that case, it is also possible to see it at low magnification. For example, two high and low magnifications, such as 500x and 10,000x, or 1,000x and 20,000x, are used. The film thickness of the resin layer was calculated by observing the film thickness at both magnifications and calculating the arithmetic average value. value.

[0045] The resin constituting the resin layer 10 is particularly preferably a resin having a viscosity that satisfies the above-mentioned relational expression (1). Such resins are not limited to ionizing radiation curable compounds (ionizing radiation polymerizable compounds). In this specification, the ionizing radiation includes, for example, a cured product (polymerization product) of a soluble compound. These include visible light, ultraviolet light, X-rays, electron beams, alpha rays, beta rays, and gamma rays. Examples of the cured product of the curable compound include urethane resins and silicone resins.

[0046] (Urethane resin) The urethane resin is a resin having a urethane bond. Cured products of radiation-curable urethane resin compositions and cured products of heat-curable urethane resin compositions, etc. Among these, from the viewpoints of obtaining high hardness, fast curing speed, and excellent mass productivity, Therefore, it is preferably a cured product of an ionizing radiation-curable urethane resin composition.

[0047] The ionizing radiation curable urethane resin composition contains a urethane (meth)acrylate. The thermosetting urethane resin composition contains a polyol compound and an isocyanate compound. Contains urethane (meth)acrylate, polyol compound, and isocyanate The compound may be any of a monomer, an oligomer, and a prepolymer.

[0048] The number of (meth)acryloyl groups (functional groups) in the urethane (meth)acrylate is 2 or less. It is preferable that the number of (meth)acryloyl groups in the urethane (meth)acrylate is 4 or less. If the number of alkyl groups is less than 2, the pencil hardness may be low. The shrinkage increases, causing the optical film to curl, and the resin layer to crack when folded. The (meth)acryloyl group in the urethane (meth)acrylate may cause The upper limit of the number is more preferably 3 or less. The term "acryloyl group" refers to a group that includes both an "acryloyl group" and a "methacryloyl group."

[0049] The weight average molecular weight of the urethane (meth)acrylate is 1,500 or more and 20,000 or less. It is preferable that the weight average molecular weight of the urethane (meth)acrylate is less than 1,500. If it is more than 20,000, the impact resistance may decrease, and if it exceeds 20,000, the ionizing radiation hardening may occur. The viscosity of the urethane resin composition increases, and the coating properties may deteriorate. p) The lower limit of the weight average molecular weight of the acrylate is more preferably 2000 or more, and the upper limit of The limit is more preferably 15,000 or less.

[0050] In addition, examples of repeating units having a structure derived from urethane (meth)acrylate include Examples include structures represented by the following general formula (1), (2), (3) or (4). [ka] In the above general formula (1), R 1 represents a branched alkyl group, and R 2 is a branched alkyl group or represents a saturated cycloaliphatic group, R 3 represents a hydrogen atom or a methyl group, R4 is a hydrogen atom, m is an integer of 0 or more; and x is an integer of 0 to 3.

[0051] [ka] In the above general formula (2), R 1 represents a branched alkyl group, and R 2 is a branched alkyl group or represents a saturated cyclic aliphatic group, R 3 represents a hydrogen atom or a methyl group, R 4 is a hydrogen atom, It represents a ethyl group or an ethyl group, n represents an integer of 1 or more, and x represents an integer of 0 to 3.

[0052] [ka] In the above general formula (3), R 1 represents a branched alkyl group, and R 2 is a branched alkyl group or represents a saturated cyclic aliphatic group, R 3 represents a hydrogen atom or a methyl group, R 4 is a hydrogen atom, m is an integer of 0 or more; and x is an integer of 0 to 3.

[0053] [ka] In the above general formula (4), R 1 represents a branched alkyl group, and R 2 is a branched alkyl group or represents a saturated cyclic aliphatic group, R 3 represents a hydrogen atom or a methyl group, R 4 is a hydrogen atom, It represents a ethyl group or an ethyl group, n represents an integer of 1 or more, and x represents an integer of 0 to 3.

[0054] In addition, the resin constituting the resin layer 10 may have any structure of polymer chains (repeating units). The formation of the fluorine-containing compound can be confirmed, for example, by pyrolysis gas chromatography mass spectrometry (GC-MS). and by analyzing the resin layer 10 by Fourier transform infrared spectroscopy (FT-IR). In particular, pyrolysis GC-MS can be used to determine the monomer units contained in the resin layer 10. This is useful because it can be detected as a mer component.

[0055] The resin layer 10 contains, in addition to the resin, an ultraviolet absorbing agent, a spectral transmittance adjusting agent, an antifouling agent, inorganic particles, and And / or it may contain organic particles, etc.

[0056] <<<Optical films>>> The optical film 30 shown in FIG. 3 is a film having a laminated structure, and includes at least a resin layer 1 In addition to the resin layer 10, the optical film 30 includes a first surface 10A of the resin layer 10 and The insulating film further includes a functional layer 31 provided on either the first surface 10B or the second surface 10C. The term "functional layer" in the description is a layer that performs some function. The functional layer 31 has a single-layer structure. However, the optical film 30 may have a multi-layer structure of two or more layers. It does not have a substrate.

[0057] The optical film 30 is foldable. The optical film 30 is folded in the following manner under an environment of relative humidity of 30% to 70%. Repeat the folding test (continuous folding test) 100,000 times, 200,000 times, 500,000 times, or 1 million times. Even if this is done, it is preferable that the optical film 30 does not crack or break. When the optical film 30 was repeatedly folded 100,000 times, If cracks or breaks occur in the film 30, the foldability of the optical film 30 becomes insufficient. The number of folding times in the above continuous folding test is evaluated to be at least 100,000 times. For example, optical films can be incorporated into foldable smartphones. If this is assumed, the frequency of folding (opening and closing) will be very high. In the above continuous folding test, the number of folding times is, for example, 10,000 or 50,000 times. In particular, for example, it may not be possible to always perform a smart evaluation. Assuming that a person who uses a mobile phone uses it, they will likely use it 5 to 10 times just during their morning commute on the train or bus. It is expected that you will open and close your smartphone at least 30 times a day. Therefore, it is assumed that the smartphone is opened and closed 30 times a day. Assuming that the number of folding times is 10,000, the continuous folding test is 30 times x 365 days = This is 10,950 times, which is a test assuming one year of use. Even if the results of the 10,000 consecutive folding tests are good, the optical filter may deteriorate after one year. Therefore, the folding speed in the continuous folding test is Evaluation of 10,000 folding times means that the product cannot be used as a product. Some products are usable but insufficient, but they are considered good and cannot be evaluated. Therefore, in order to evaluate whether it is at a practical level, the folding speed of the above continuous folding test The number of folding times must be at least 100,000. It is more preferable that the bent portion does not deform when the folding test is performed. The optical film 30 may be folded so that the surface 30A is on the outside. The optical film 30 may be folded so that the surface 30A faces inward. Even in this case, it is preferable that the optical film 30 does not crack or break.

[0058] The continuous folding test is carried out as follows. In the test, first, a sample of 30 mm x 100 mm in size was taken from the optical film. Cut out the sample S from the optical film 30. The sample size is 30 mm x 100 mm. If you cannot cut out S, cut the sample S to a size of, for example, 10 mm x 100 mm. Then, the side S1 of the cut sample S and the side S opposite to the side S1 are 2 and a folding durability tester (for example, product name "U-shaped stretch tester DLD MLH-FS, manufactured by Yuasa System Devices, Ltd., compliant with IEC62715-6-1) The sample S is fixed by the fixing parts 40 and 45. This is done by holding a portion of the sample S approximately 10 mm on one side in the direction of the sample. If the sample S is smaller than the above size, the portion of the sample S required for this fixation If the distance is up to about 20 mm, it can be measured by attaching it to the fixing parts 40 and 45 with tape. As shown in FIG. 4A, the fixing portion 40 is slidable in the horizontal direction. The above device is different from the conventional method of wrapping a sample around a rod. This allows the evaluation of the durability of the sample against bending load without generating tension or friction. This is possible and preferable.

[0059] Next, as shown in FIG. 4B, the fixing portion 40 is moved close to the fixing portion 45. By this, the center of sample S is folded and deformed, as shown in Fig. 4(C). The distance φ between the two opposing sides S1 and S2 of the sample S fixed by the fixing parts 40 and 45 is After moving the fixing part 40 to a position where the distance is 10 mm, the fixing part 40 is moved in the opposite direction. The deformation of the optical film 30 is eliminated.

[0060] As shown in FIG. 4(A) to (C), the fixing part 40 is moved to the center of the sample S. The sample S can be folded by 180°. The continuous folding test is carried out under the following conditions so that the bottom end does not protrude, and the fixed part is By controlling the distance φ when 40 and 45 are closest to each other, the two opposing sides of the sample S The distance φ between the bent portions S1 and S2 can be set to 10 mm. In this case, the outer diameter of the bent portion S3 is set to 10 mm. In sample S, the distance φ between the opposing sides of sample S is set to 10 mm. No cracks or breaks will occur when the product is repeatedly folded 180 degrees 100,000 times. However, it is preferable that the distance φ between the opposing sides S1 and S2 of the sample S is 8 mm or 6 mm. When the test piece was repeatedly folded 180 degrees 100,000 times, it did not crack or break. It is more preferable that no breakage occurs. (Folding conditions) Reciprocating speed: 40 rpm (revolutions per minute) Test stroke: 60mm Bending angle: 180°

[0061] The surface 30A of the optical film 30 (the surface 31A of the functional layer 31) is JIS K5600- The hardness (pencil hardness) measured by the pencil hardness test specified in ITU-T R6010-1999 is 3. The pencil hardness test is preferably 3H or higher, and more preferably 4H or higher. The optical film 30 was cut into a size of 0 mm x 100 mm and placed on a glass plate without any folds or wrinkles. The samples were fixed with cellophane tape (registered trademark) manufactured by Iyo Nichiban Co., Ltd. and stored at a temperature of 23±5°C and a In an environment with a humidity of 30% or more and 70% or less, the surface 30A of the optical film 30 is subjected to a pencil hardness test. Testing machine (for example, product name "Pencil scratch coating hardness tester (electric type)", Toyo Seiki Co., Ltd. Using a pencil (e.g., product name "Uni", manufactured by Mitsubishi Pencil Co., Ltd.), add 750 g The test is carried out by moving the pencil at a speed of 1 mm / sec while applying a load of The pencil hardness is the highest hardness that does not scratch the surface of the optical film in the pencil hardness test. When measuring pencil hardness, several pencils with different hardness are used. The pencil hardness test was carried out five times with each brush, and the surface of the optical film was scratched four or more times out of the five. When the pencil had not been used, the surface of the optical film was not scratched by the pencil of this hardness. The above scratches are judged to be due to the fact that the surface of the optical film that has been subjected to the pencil hardness test is observed under a fluorescent lamp. This refers to something that can be seen as a

[0062] The total light transmittance of the optical film 30 is, for the same reason as explained in the section of the resin layer 10, It is preferable that the content is 85% or more, and more preferably 87% or more, 88% or more, or 90% or more. It is more preferable that the total light transmittance of the optical film 30 is measured by the total light transmittance of the resin layer 10. The measurement is performed in the same manner as the determination method.

[0063] The haze value (total haze value) of the optical film 30 is the same as that of the resin layer 10. For these reasons, it is preferable that the content is 3.0% or less, and more preferably 2.0% or less, 1.5% or less, or 1.0% or less. The haze value of the optical film 30 is preferably 0.5% or less. The haze value of the oil layer 10 is measured in the same manner as described above.

[0064] A polarizing plate or the like is attached to the front surface 30A side or the back surface 30B side of the optical film 30 via an adhesive layer or a bonding layer. If other films are installed, peel them off together with the adhesive layer or bonding layer. Then, a folding test, total light transmittance measurement, haze value measurement, etc. shall be performed. Even if such a peeling process is performed, it does not have a significant effect on these tests or measurements. The haze value is measured by removing the adhesive layer or the bond layer, and then removing the dirt from the adhesive layer or the bond layer. This should be done after wiping thoroughly with kohl.

[0065] The use of the optical film 30 is not particularly limited, but examples of the use of the optical film 30 include: For example, smartphones, tablet devices, personal computers (PCs), wearables Image display devices such as mobile terminals, digital signage, televisions, and car navigation systems The optical film 30 is also suitable for use in vehicles. The shape of the material is suitable for applications that require flexibility, such as foldable and rollable. is also preferred.

[0066] The optical film 30 may be cut to a desired size, or may be in a roll. When the optical film 30 is cut to a desired size, the size of the optical film is not particularly limited and is appropriately determined depending on the size of the display surface of the image display device. The size of the optical film 30 is, for example, 2.8 inches or more and 500 inches or less. In this specification, "inch" means that when the optical film has a rectangular shape, It means the length of the diagonal, in the case of a circle, it means the diameter, in the case of an ellipse, The average value of the sum of the minor axis and the major axis is used here. In this case, the aspect ratio of the optical film when calculating the above inches is the display screen of the image display device. There is no particular limitation as long as there is no problem. For example, vertical:horizontal=1:1, 4:3, 16:10, 16 However, especially for in-vehicle applications and digital signage, The aspect ratio of the optical film 30 is not limited to this. If the size is large, cut it out from any position to A5 size (148mm x 210mm). Then, the pieces are cut out to the size of each measurement item. In the case where the optical film 30 is in a roll shape, a predetermined length is unwound from the roll. At the same time, the roll is not in an ineffective region including both ends extending along the longitudinal direction of the roll, but in an area of ​​stable quality. The desired size is cut out from the effective area near the center of the image.

[0067] The optical film 30 in the image display device may be disposed inside the image display device. It is preferable that the surface of the image display device is used near the surface of the image display device. When the optical film 30 is used, the optical film 30 is a cover film ( It functions as a window film.

[0068] <<Functional Layer>> The functional layer 31 is provided on the first surface 10A side of the resin layer 10, i.e., on the first region 10C side. In this way, by providing the functional layer 31 on the first region 10C side, It has excellent scratch resistance and does not impair its excellent foldability.

[0069] The functional layer 31 shown in FIG. 3 is a layer that mainly provides hardness to the optical film 30. Specifically, the functional layer 31 is a layer that functions as a hard coat layer. In the present embodiment, the term "hard coat layer" refers to a layer that is a cross-section of a functional layer. This refers to a layer having a Martens hardness (HM) of 375 MPa or more at the center of the surface. In this specification, the term "Martens hardness" refers to the hardness measured by the nanoindentation method. The hardness is measured when the indenter is pressed 500 nm into the specimen. The Martens hardness was measured on an optical film cut to a size of 30 mm x 30 mm. We used the Bruker TI950 TriboIndenter. That is, the measurement is performed under the following measurement conditions, using a Berkovich indenter as the indenter. (Triangular pyramid, e.g., TI-0039 manufactured by Bruker) is placed 500 degrees perpendicular to the cross section of the functional layer. Here, the Berkovich indenter is pressed in at 100 nm to avoid the influence of the side edges of the resin layer and the functional layer. The interface between the resin layer and the functional layer was 500 nm away from the center of the functional layer, and the two ends of the functional layer were Each of them is pushed into the part of the functional layer that is 500 nm or more away from the center of the functional layer. After that, the residual stress was relaxed by holding it constant, and then the load was removed and the maximum load after relaxation was measured. , the maximum load P max and the area A of the depression with a depth of 500 nm, max / A, Calculate the Martens hardness. The Martens hardness is the arithmetic average of the values ​​measured at 10 points. If the measured values ​​include values ​​that deviate from the arithmetic mean value by ±20% or more, If any of the measured values ​​is within ±20% of the arithmetic mean value, the measured value shall be excluded and remeasured. The presence or absence of deviations of % or more is determined by taking the measured value as A and the arithmetic mean value as B. , whether the value (%) calculated by (AB) / B×100 is ±20% or more The matter shall be decided at its discretion. (Measurement conditions) Control method: Displacement control ·Loading speed: 10nm / sec ·Holding time: 5 seconds ·Loading and unloading speed: 10nm / sec ·Measurement temperature: 23±5℃ ·Measurement humidity: 30%~70%

[0070] The Martens hardness of the functional layer 31 is preferably 375 MPa or more and 1500 MPa or less. It is preferable that the Martens hardness of the functional layer 31 is 375 MPa or more. If the strength is 1500 MPa or less, good folding performance can be obtained.

[0071] The thickness of the functional layer 31 is preferably 3 μm or more and 10 μm or less. If the thickness of the film 1 is 3 μm or more, good hardness can be obtained, and if it is 10 μm or less, In this specification, the term "film thickness of the functional layer" refers to the thickness of the functional layer. In the case of a layered structure, the thickness refers to the total thickness of each functional layer. The lower limit of the thickness of the functional layer 31 is preferably 4 μm or more, more preferably 5 μm or more. The upper limit is preferably 8 μm or less, and more preferably 7 μm or less.

[0072] The thickness of the functional layer 31 is measured by a scanning transmission electron microscope (STEM) or a transmission electron microscope ( A cross section of the functional layer 31 is photographed using a TEM, and the film of the functional layer 31 is The thickness is measured at 10 points, and the arithmetic average value of the thicknesses at the 10 points is used. In this case, first, a measurement sample is prepared in the same manner as for the resin layer 10. Then, a scanning transmission electron microscope (STEM) (e.g., product name "S-4800", Nippon Koei Co., Ltd.) was used. The cross-sectional photograph of the measurement sample is taken using a microscope (manufactured by Ritsumeikan High Technologies). When taking cross-sectional photographs using 00, the detector is set to "TE", the accelerating voltage is set to "30kV", The cross-section is observed with the emission current set to 10 μA. Adjust the contrast and brightness and observe whether each layer can be distinguished by magnification from 5000 to 200. The magnification is preferably 10,000 to 100,000 times, and more preferably 10,000 to The magnification is preferably 50,000 times, and the most preferable magnification is 25,000 times to 50,000 times. When taking cross-sectional photographs using the objective lens, set the beam monitor aperture to "3" and You can also set the aperture to "3" and the WD to "8 mm". Measure the film thickness of the functional layer. In this case, when observing the cross section, the interface contrast between the functional layer and other layers (e.g., resin layer) is It is important to be able to observe as clearly as possible. If the interface is not visible due to lack of contrast, If it is difficult to obtain a clear image, dyeing with osmium tetroxide, ruthenium tetroxide, phosphotungstic acid, etc. Since the interface between the organic layers becomes easier to see when the organic layer is treated, a dyeing process may be performed. The contrast of the image may be more difficult to see at higher magnifications. In that case, the same can be said for low magnifications. For example, two magnifications, high and low, such as 25,000 times and 50,000 times, or 50,000 times and 100,000 times, are used. The arithmetic mean value was calculated at both magnifications, and the average value was used as the film thickness value of the functional layer. Let us assume that.

[0073] The functional layer 31 preferably further contains a resin and inorganic particles dispersed in the resin. stomach.

[0074] <Resin> The resin contains a polymer (cured product) of a polymerizable compound (curable compound). It has at least one polymerizable functional group in the molecule. The polymerizable functional group is, for example, Examples of the unsaturated groups include ethylenically unsaturated groups such as (meth)acryloyl groups, vinyl groups, and allyl groups. .

[0075] As the polymerizable compound, a polyfunctional (meth)acrylate is preferable. Examples of acrylates include trimethylolpropane tri(meth)acrylate, Dipropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate acrylate, dipropylene glycol di(meth)acrylate, pentaerythritol triacrylate (Meth)acrylate, Pentaerythritol Tetra(Meth)acrylate, Dipentaerythritol Lithritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate acrylate, neopentyl glycol di(meth)acrylate, ditrimethylolpropanediol Dipentaerythritol penta(meth)acrylate, Tripentaerythritol penta(meth)acrylate Pentaerythritol octa(meth)acrylate, tetrapentaerythritol deca( meth)acrylate, isocyanuric acid tri(meth)acrylate, isocyanuric acid di(meth)acrylate Polyester tri(meth)acrylate, polyester di(meth)acrylate Acrylate, bisphenol di(meth)acrylate, diglycerin tetra(meth)acrylate acrylate, adamantyl di(meth)acrylate, isobornyl di(meth)acrylate , dicyclopentane di(meth)acrylate, tricyclodecane di(meth)acrylate and those modified with PO, EO, caprolactone, etc.

[0076] Among these, those having three to six functional groups are preferred because they can satisfactorily satisfy the above-mentioned Martens hardness. For example, pentaerythritol triacrylate (PETA), dipenta Erythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate Dipentaerythritol pentaacrylate (PETTA), Dipentaerythritol pentaacrylate (DPPA), Trimethicone Tyrolpropane tri(meth)acrylate, Tripentaerythritol octa(meth)acrylate acrylate, tetrapentaerythritol deca(meth)acrylate, etc. are preferred. In this specification, (meth)acrylate refers to acrylate and methacrylate. It means.

[0077] In order to adjust the hardness and viscosity of the composition, improve adhesion, etc., a monofunctional (meth)acrylic acid may be further added. The monofunctional (meth)acrylate monomer may include a methacrylate monomer. For example, hydroxyethyl acrylate (HEA), glycidyl methacrylate, Polyethylene glycol (meth)acrylate, isostearyl (meth)acrylate , 2-Acryloyloxyethyl succinate, acryloylmorpholine, N-Acryloyl Triethyloxyethylhexahydrophthalimide, Cyclohexyl acrylate, Tetrahydantoyl Drofulyl acrylate, isobornyl acrylate, phenoxyethyl acrylate, and adamantyl acrylate.

[0078] The weight average molecular weight of the monomer is less than 1000 from the viewpoint of improving the hardness of the resin layer. The weight of the polymerizable oligomer is preferably from 200 to 800, and more preferably from 200 to 800. The average molecular weight is preferably 1,000 or more and 20,000 or less, and more preferably 1,000 or more and 10,000 or less. It is more preferable that the molecular weight is 2,000 or more and 7,000 or less, and further more preferable that the molecular weight is 2,000 or more and 7,000 or less.

[0079] <Inorganic particles> The inorganic particles are not particularly limited as long as they can improve the hardness. From the viewpoint of obtaining a high degree of adhesion, silica particles are preferred. Among silica particles, reactive silica particles are preferred. The reactive silica particles preferably form a crosslinked structure with the polyfunctional (meth)acrylate. The reactive silica particles can be used to form a functional The hardness of the layer 31 can be sufficiently increased.

[0080] The reactive silica particles preferably have a reactive functional group on the surface thereof. As the functional group, for example, the above-mentioned polymerizable functional groups are preferably used.

[0081] The reactive silica particles are not particularly limited, and any conventionally known reactive silica particles may be used. For example, reactive silica particles described in JP-A-2008-165040 can be mentioned. In addition, examples of commercially available reactive silica particles include MIBK-SD and MIBK-SD -MS, MIBK-SD-L, MIBK-SD-ZL (all manufactured by Nissan Chemical Industries, Ltd.) Examples of such Catalysts include V8802 and V8803 (all manufactured by JGC Catalysts and Chemicals Co., Ltd.).

[0082] The silica particles may be spherical silica particles, but are preferably irregularly shaped silica particles. It is preferable to mix the spherical silica particles with the irregularly shaped silica particles. The term "spherical silica particles" refers to silica particles having a spherical shape, an oval spherical shape, or the like. In addition, "irregularly shaped silica particles" are potato-shaped (with an aspect ratio of 1.2 or more when observed in cross section). The irregularly shaped silica particles refer to silica particles having random irregularities on the surface. Since the surface area of ​​silica particles is larger than that of spherical silica particles, these irregularly shaped silica particles By containing the molecule, the contact area with the polyfunctional (meth)acrylate etc. is increased, The hardness of the hard coat layer can be improved. Whether or not the silica particles are irregularly shaped can be determined by examining the cross section of the functional layer with a transmission electron microscope (TEM) or a scanning electron microscope. This can be confirmed by observation with a scanning electron microscope (STEM).

[0083] The average particle size of the silica particles is preferably 5 nm or more and 200 nm or less. If the average particle size of the Rica particles is 5 nm or more, the particles themselves will not be difficult to manufacture, and the particles will not be easily separated. The aggregation of the silica particles can be suppressed, and it is not difficult to form the silica particles into an irregular shape. If the average particle size is 200 nm or less, the formation of large irregularities in the functional layer can be suppressed. In addition, the increase in haze can be suppressed. When the silica particles are spherical, The average particle size was measured using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). The particle diameters of 20 particles were measured from the cross-sectional images of the particles taken using a In addition, when the silica particles are irregularly shaped silica particles, the arithmetic mean value of the particle diameter is used. The average particle size of the particles was measured using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). ) was used to photograph the cross-section of the hard coat layer, and the maximum distance between two points on the periphery of the particle ( The particle size was calculated by averaging the major axis (longest diameter) and the minimum axis (shortest diameter), and the particle size of 20 particles was calculated. The surgical mean value is used.

[0084] By controlling the size and amount of the inorganic particles, the hardness (Martens hardness) of the functional layer 31 can be adjusted. For example, when forming the functional layer 31, the silica particles have a diameter of 5 nm. or more and 200 nm or less, and 25 to 60 parts by mass relative to 100 parts by mass of the polymerizable compound. It is preferable that:

[0085] The functional layer 31 may contain materials other than those mentioned above as long as the above-mentioned Martens hardness is satisfied. For example, the resin component may be a material that forms a hardened product by irradiation with ionizing radiation. The polymerizable monomer or oligomer may contain the above polymerizable monomer or oligomer. The polymerizable oligomer may be, for example, a (meth) oligomer having a radical polymerizable unsaturated group in the molecule. Acrylate monomer or (meth)acrylate having a radical polymerizable unsaturated group in the molecule The above-mentioned (meth)-type oligomers have radical polymerizable unsaturated groups in the molecule. Acrylate monomer or (meth)acrylate having a radical polymerizable unsaturated group in the molecule Examples of the acrylate oligomer include urethane (meth)acrylate, polyester (meth)acrylate, and the like. (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, poly Monomers such as trifluoroalkyl (meth)acrylate and silicone (meth)acrylate These polymerizable monomers or oligomers may be one or more of the polymerizable monomers or oligomers. Two or more of these may be used in combination. Urethane (meth)acrylates having a molecular weight of 1,000 to 10,000 are preferred.

[0086] The functional layer 31 further includes an ultraviolet absorbing agent, a spectral transmittance adjusting agent, and / or an antifouling agent. It's okay to be.

[0087] <<<Other optical films>>> The optical film 30 shown in FIG. 3 does not include a substrate, but the optical film 30 shown in FIG. The optical film 50 may have a substrate such as the optical film 50 shown in FIG. The resin layer 10, the resin substrate 51, and the functional layer 52 are arranged in this order. It is preferable that the second surface 10A of the resin layer 10 is provided on the optical film 5. In the example shown in FIG. 1, the resin layer 10 is provided directly on the resin substrate 51, but the resin layer 10 is attached to the resin substrate 51 via an adhesive layer. It may be attached to a fatty substrate.

[0088] The surface 50A of the optical film 50 is the surface 52A of the functional layer 52. In this document, the surface of the optical film is used to mean one side of the optical film. The side opposite to the optical film surface is called the back side to distinguish it from the optical film surface. The rear surface 50B of the optical film 50 is the second surface 10B of the resin layer 10. is.

[0089] The optical film 50 is also foldable like the optical film 30. The number of folding times, the preferred distance φ between the opposing sides, and the conditions of the continuous folding test are determined based on the optical Since it is similar to the film 30, the explanation will be omitted here.

[0090] The surface 50A of the optical film 50 (the surface 52A of the functional layer 52) is JIS K5600- The hardness (pencil hardness) measured by the pencil hardness test specified in ITU-T R6010-1999 is 2. The pencil hardness of the optical film 50 is preferably B or higher. It shall be measured in the same manner as hardness.

[0091] The optical film 50 preferably has a yellow index (YI) of 15 or less. If the YI of the optical film 50 is 15 or less, the yellowish color of the optical film can be suppressed and the optical film can be transparent. The yellow index (YI) of optical film 50 is The upper limit is more preferably 10 or less, 5 or less, or 1.5 or less. YI is stored in an environment with a temperature of 23±5°C and a relative humidity of 30% to 70%. Spectrophotometer (e.g., product name "UV-2450", manufactured by Shimadzu Corporation, light source: tungsten The optical filter cut to a size of 50 mm x 100 mm was placed inside the lamp and deuterium lamp. The optical film was measured with the resin layer side of the film facing the light source. According to the calculation formula described in JIS Z8722:2009, the transmittance from Calculate the chromaticity tristimulus values ​​X, Y, and Z, and convert them to ASTM D1925:19 The value was calculated according to the formula described in 62. The upper limit of the yellow index (YI) is more preferably 10 or less. The YI is calculated by measuring three times for one optical film and calculating the arithmetic mean of the three measurements. The average value is used. For UV-2450, the yellow index is the same as for UV-24. On the monitor connected to the 50, read the transmittance measurement data and select "Y The calculation is performed by checking the "I" item. The transmittance was measured under the following conditions, with wavelengths of 300 nm to 780 nm at approximately 1 n The transmittance is measured at a minimum of five points between the two points and the average value is calculated. If there are any undulations in the spectrum of the spectral transmittance, the delta should be set to 5.0. Smoothing may be performed at nm. (Measurement conditions) ·Wavelength range: 300nm~780nm Scan speed: Fast Slit width: 2.0 Sampling interval: Auto (0.5 nm interval) ·Lighting:C Light source: D2 and WI ·Field of view: 2° Light source switching wavelength: 360nm S / R Switching: Standard Detector: PM Autozero: Performed at 550 nm after baseline scan

[0092] The total light transmittance of the optical film 50 is, for the same reason as explained in the section of the resin layer 10, It is preferably 85% or more, more preferably 87% or more, or even more preferably 90% or more. The total light transmittance of the optical film 50 was measured in the same manner as the total light transmittance of the resin layer 10. It is measured by the method.

[0093] The haze value (total haze value) of the optical film 50 is the same as that of the resin layer 10. For these reasons, it is preferable that the content is 3.0% or less, and more preferably 2.0% or less, 1.5% or less, or 1.0% or less. The haze value of the optical film 50 is preferably 0.5% or less. The haze value of the oil layer 10 is measured in the same manner as described above.

[0094] <<Resin substrate>> The resin base material 51 has optical transparency. The resin base material 51 is made of, for example, a polyimide resin. , polyamide-imide resins, polyamide-based resins, and polyester-based resins (e.g., poly Polyethylene terephthalate resin and polyethylene naphthalate resin) It is preferable that the resin contains one or more resins that can be used in the present invention.

[0095] Among these resins, only the one that is least likely to crack or break during the continuous folding test It has excellent hardness and transparency, and is also excellent in heat resistance. It becomes even more stable after firing. From the viewpoint of being able to impart excellent hardness and transparency to the Among these, preferred are olefin-based resins, olefin-based resins, and mixtures thereof.

[0096] Polyimide resins are obtained by reacting a tetracarboxylic acid component with a diamine component. The polyimide resin is not particularly limited, but may be, for example, a polyimide resin having excellent light transmittance and From the viewpoint of having excellent rigidity, the following general formula (5) and the following general formula (7) are preferred: It is preferable that the polycyclic aromatic hydrocarbon has at least one structure selected from the group consisting of the following structures:

[0097] [ka] In the above general formula (5), R 5 is a tetravalent group which is a tetracarboxylic acid residue, R 6 t trans-Cyclohexanediamine residue, trans-1,4-bismethylenecyclohexane Sandiamine residue, 4,4'-diaminodiphenyl sulfone residue, 3,4'-diaminodiphenyl A divalent group selected from the group consisting of a phenylsulfone residue and a divalent group represented by the following general formula (6): n represents the number of repeating units and is 1 or more. In the details, "tetracarboxylic acid residue" means a residue obtained by isolating four carboxylates from a tetracarboxylic acid. This refers to the residue obtained by removing the silyl group, and is the residue obtained by removing the acid dianhydride structure from a tetracarboxylic dianhydride. The term "diamine residue" refers to a diamine with two amino groups removed. This refers to a residue.

[0098] [ka] In the above general formula (6), R 7 and R 8 each independently represents a hydrogen atom, an alkyl group, or a perfluoroalkyl group.

[0099] [ka] In the above general formula (7), R 9 is the residue of cyclohexanetetracarboxylic acid, Tantalumtetracarboxylic acid residue, dicyclohexane-3,4,3',4'-tetracarboxylic acid residues, and 4,4'-(hexafluoroisopropylidene)diphthalic acid residues At least one tetravalent group selected from R 10 represents a divalent group which is a diamine residue n' represents the number of repeating units and is 1 or more.

[0100] In the above general formula (5), R 5 is a tetracarboxylic acid residue, as exemplified above. The above-mentioned tetracarboxylic dianhydride can be a residue obtained by removing the acid dianhydride structure from the above-mentioned tetracarboxylic dianhydride. R in general formula (5) 5 Among other things, the objective is to improve light transmittance and rigidity. From 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 3,3',4, 4'-biphenyltetracarboxylic acid residue, pyromellitic acid residue, 2,3',3,4'-biphenyltetracarboxylic acid residue Phenyltetracarboxylic acid residue, 3,3',4,4'-benzophenonetetracarboxylic acid Residue, 3,3',4,4'-diphenylsulfonetetracarboxylic acid residue, 4,4'-oxy Diphthalic acid residue, cyclohexanetetracarboxylic acid residue, and cyclopentanetetracarboxylic acid residue It is preferable that the carboxylic acid residue contains at least one selected from the group consisting of carboxylic acid residues, and further contains 4,4'-(Hexafluoroisopropylidene)diphthalic acid residue, 4,4'-oxydiphthalic acid residue from tetracarboxylic acid residues and 3,3',4,4'-diphenylsulfonetetracarboxylic acid residues It is preferable that the compound contains at least one selected from the group consisting of:

[0101] R 5 In the above, it is preferable that the total amount of these suitable residues is 50 mol % or more, and It is preferable that the content is 70 mol % or more, and more preferably 90 mol % or more.

[0102] Also, R 5 3,3',4,4'-biphenyltetracarboxylic acid residue, 3,3' , 4,4'-benzophenonetetracarboxylic acid residues, and pyromellitic acid residues. Tetracarboxylic acids suitable for improving stiffness, such as at least one selected from the group Group A and 4,4'-(hexafluoroisopropylidene)diphthalic acid residues group, 2,3',3,4'-biphenyltetracarboxylic acid residue, 3,3',4,4'-diphenyl Phenylsulfonetetracarboxylic acid residue, 4,4'-oxydiphthalic acid residue, cyclohexa cyclopentanetetracarboxylic acid residues, and cyclopentanetetracarboxylic acid residues. At least one of the tetracarboxylic acid residues suitable for improving transparency is selected from the group consisting of It is also preferable to use a mixture of these with group B).

[0103] In this case, the tetracarboxylic acid residue group (group A) suitable for improving the rigidity and The content ratio of the tetracarboxylic acid residue group (Group B) suitable for improving transparency is as follows: For every 1 mole of tetracarboxylic acid residue group (Group B) suitable for improving transparency, The tetracarboxylic acid residue group (group A) suitable for improving the rigidity is 0.05 mol or less. It is preferably from 0.1 to 5 mol, more preferably from 0.1 to 5 mol. The amount is preferably 0.3 mol or more and more preferably 4 mol or less.

[0104] R in the above general formula (5) 6 Among other things, the objective is to improve light transmittance and rigidity. From the viewpoint of a divalent group represented by the general formula (6) At least one divalent group is preferred, and further, 4,4'-diaminodiphenylsulfonyl is preferably used. sulfone residue, 3,4'-diaminodiphenylsulfone residue, and R 7 and R 8 but A divalent group represented by the above general formula (6), which is a perfluoroalkyl group, is selected from the group consisting of the divalent group represented by the above general formula (6). It is preferable that the aryl group is at least one divalent group.

[0105] R in the above general formula (7) 9 Among other things, the objective is to improve light transmittance and rigidity. From this viewpoint, 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 3,3' ,4,4'-diphenylsulfonetetracarboxylic acid residues, and oxydiphthalic acid residues. It is preferable to do so.

[0106] R 9In the above, it is preferable that the content of these suitable residues is 50 mol % or more, and more preferably 70 It is preferable that the content is 90 mol % or more, and more preferably 90 mol % or more.

[0107] R in the above general formula (7) 10 is a diamine residue, and the diamines exemplified above are The R in the above general formula (7) can be a residue obtained by removing two amino groups from the R 1 0 Among them, 2,2'-bis( (trifluoromethyl)benzidine residue, bis[4-(4-aminophenoxy)phenyl] Sulfone residue, 4,4'-diaminodiphenyl sulfone residue, 2,2-bis[4-(4- aminophenoxy)phenyl]hexafluoropropane residue, bis[4-(3-aminophenoxy)phenyl]hexafluoropropane residue 4,4'-diamino-2,2'-bis(trifluorophenyl)sulfone residue 1,4-bis[4-amino-2-(trifluoromethyl)diphenyl ether residue, 2,2-bis[4-(4-amino-2-trifluorophenyl)phenoxy]benzene residue, Methylphenoxy)phenyl]hexafluoropropane residue, 4,4'-diamino-2- (Trifluoromethyl)diphenyl ether residue, 4,4'-diaminobenzanilide residue group, N,N'-bis(4-aminophenyl)terephthalamide residue, and 9,9-bis( At least one divalent group selected from the group consisting of 4-aminophenyl)fluorene residues and preferably further comprises a 2,2'-bis(trifluoromethyl)benzidine residue, Bis[4-(4-aminophenoxy)phenyl]sulfone residue, and 4,4'-diamino It contains at least one divalent group selected from the group consisting of diphenyl sulfone residues. preferable.

[0108] R 10 In the above, it is preferable that the total amount of these suitable residues is 50 mol % or more. The content is more preferably 70 mol % or more, and even more preferably 90 mol % or more.

[0109] Also, R 10 as a bis[4-(4-aminophenoxy)phenyl]sulfone residue, 4,4'-Diaminobenzanilide residue, N,N'-bis(4-aminophenyl)terephthalic acid thalamide residue, paraphenylenediamine residue, metaphenylenediamine residue, and 4 , 4'-diaminodiphenylmethane residues. Group C is a diamine group suitable for improving the rigidity of the polymer, and Group C is a 2,2'-bis(triamine) group suitable for improving the rigidity of the polymer. fluoromethyl)benzidine residue, 4,4'-diaminodiphenylsulfone residue, 2,2 -Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residue, bis[ 4-(3-aminophenoxy)phenyl]sulfone residue, 4,4'-diamino-2,2' -Bis(trifluoromethyl)diphenyl ether residue, 1,4-bis[4-amino-2 -(trifluoromethyl)phenoxy]benzene residue, 2,2-bis[4-(4-amino -2-trifluoromethylphenoxy)phenyl]hexafluoropropane residue, 4,4 '-Diamino-2-(trifluoromethyl)diphenyl ether residue, and 9,9-bis (4-aminophenyl)fluorene residues. It is also possible to use it in combination with a diamine residue group (group D) suitable for improving transparency. preferable.

[0110] In this case, the diamine residue group (group C) suitable for improving the rigidity and the transparency The content ratio of the diamine residue group (group D) suitable for improving transparency is For 1 mole of the diamine residue group (group D) suitable for improving the rigidity, The amount of the diamine residue group (group C) is preferably 0.05 moles or more and 9 moles or less. The amount is preferably 0.1 mol or more and 5 mol or less, and more preferably 0.3 mol or more and 4 mol or less. It is more preferable to do so.

[0111] In the structures represented by the above general formula (5) and the above general formula (7), n and n' are Each independently represents the number of repeating units, which is 1 or more. The number n may be appropriately selected depending on the structure so as to exhibit a preferred glass transition temperature, which will be described later. The average number of repeating units is usually 10 to 2000, and more preferably 15 It is preferable that the ratio is 1 to 1000.

[0112] The polyimide resin may partially contain a polyamide structure. Examples of polyamide structures that may be used include tricarboxylic acids such as trimellitic anhydride. Polyamide-imide structures containing acid residues and polyamides containing dicarboxylic acid residues such as terephthalic acid are also available. An example of such an amide structure is

[0113] From the viewpoint of heat resistance, it is preferable that the polyimide resin has a glass transition temperature of 250° C. or higher. On the other hand, it is preferable that the temperature is 270° C. or higher in view of ease of stretching and low bake temperature. From the viewpoint of reducing the amount of the resin, the glass transition temperature is preferably 400° C. or less, and more preferably 380° C. or less. It is preferable that:

[0114] Examples of polyimide resins include compounds having a structure represented by the following chemical formula: In the following chemical formula, n is a repeating unit and represents an integer of 2 or more. [ka]

[0115] [ka]

[0116] [ka]

[0117] [ka]

[0118] [ka]

[0119] [ka]

[0120] [ka]

[0121] [ka]

[0122] [ka]

[0123] [ka]

[0124] [ka]

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129] [ka]

[0130] [ka]

[0131] Among the polyimide resins, the polyimide resin has excellent transparency, and therefore, Polyimide resins or polyamide resins having a structure in which charge transfer is unlikely to occur are preferred. Specifically, fluorinated polyimide resins such as those represented by the above chemical formulas (8) to (15) and those represented by the above formula ( Examples of the polyimide resins include those having an alicyclic structure such as 15) to (19).

[0132] In addition, in the fluorinated polyimide resins represented by the above chemical formulas (8) to (15), It has a high heat resistance due to its structure, and is a polyimide film made of polyimide resin. It has excellent transparency because it is not discolored by the heat during the film production.

[0133] Polyamide resins include not only aliphatic polyamides but also aromatic polyamides (aramids). The polyamide resin is, for example, a polyamide resin represented by the following chemical formulas (25) to (27). In the following formula, n is a repeating unit. , represents an integer of 2 or greater.

[0134] [ka]

[0135] [ka]

[0136] [ka]

[0137] Polyimide resins or polyamide resins represented by the above chemical formulas (8) to (24) and (27) The substrate made of polyimide resin may be a commercially available one. Examples of commercially available materials include Neoprim (registered trademark) manufactured by Mitsubishi Gas Chemical Company, Inc. Examples of commercially available substrates containing the polyamide resin include Mikto, manufactured by Toray Industries, Inc. Examples include Ron (registered trademark).

[0138] Also, the polyimide resins represented by the above chemical formulas (8) to (24) and (27) or The polyamide resin may be synthesized by a known method. The synthesis method of the polyimide resin represented by formula (8) is described in JP 2009-132091 A. Specifically, 4,4'-hexafluoropropane represented by the following chemical formula (28) is Pyridenebisphthalic dianhydride (FPA) and 2,2'-bis(trifluoromethyl)-4 ,4'-diaminobiphenyl (TFDB) can be obtained by reacting with [ka]

[0139] The weight average molecular weight of the polyimide resin or polyamide resin is 3000 or more and 50 It is preferable that the range is 5,000 to 300,000. The weight average molecular weight is preferably in the range of 10,000 to 200,000, and more preferably in the range of 10,000 to 200,000. If it is less than 0, sufficient strength may not be obtained, and if it exceeds 500,000, the viscosity increases, As a result of the decrease in solubility, it may not be possible to obtain a substrate with a smooth surface and a uniform film thickness. In this specification, the "weight average molecular weight" refers to the molecular weight determined by gel permeation chromatography (GPC). The values ​​are polystyrene equivalent values ​​measured by the method described above.

[0140] From the viewpoint of being able to improve hardness, the resin base material 51 is ) or a fluorinated polyimide resin having a halogen group such as the above chemical formula (27). It is preferable to use a substrate made of a polyamide resin that has high hardness. From the viewpoint of being able to form a substrate comprising a polyimide resin represented by the above chemical formula (8), It is more preferable to use

[0141] Examples of polyester resins include polyethylene terephthalate and polypropylene. terephthalate, polybutylene terephthalate, polyethylene naphthalate Examples of the resin include a resin having one type as a constituent.

[0142] The thickness of the resin base material 51 is preferably 10 μm or more and 100 μm or less. If the thickness of the resin base material 51 is 10 μm or more, curling of the optical film can be suppressed and Furthermore, when optical films are manufactured by roll to roll, Even in the case of using a resin substrate, wrinkles are unlikely to occur, and there is no risk of the appearance being deteriorated. If the thickness of 51 is 100 μm or less, the folding performance of the optical film 50 is good, It is possible to satisfy the requirements of the continuous folding test, and the optical film 50 is lightweight. The thickness of the resin substrate 51 is preferably measured by the same method as that for the film thickness of the resin layer 10. The lower limit of the resin base material 51 is 20 μm or more, 30 μm or more, or 40 μm or more. It is more preferable that the upper limit of the resin base material 51 is 80 μm or less, or 50 μm or less. It is more preferable to do so.

[0143] <Functional layer> The functional layer 52 is similar to the functional layer 31, and therefore a description thereof will be omitted here.

[0144] <<<Method of manufacturing resin layer and optical film>>> The resin layer 10 and the optical films 30 and 50 can be produced as follows. When preparing the resin layer 10 and the optical film 30, first, one side of the release film is A resin layer composition is applied onto the surface using a coating device such as a bar coater to form a coating film. .

[0145] <<Composition for resin layer>> The composition for the resin layer contains at least an ionizing radiation curable compound. In addition to the ionizing radiation curable compound, the composition may further contain a solvent and a polymerization initiator. The material has been explained in the section on the resin layer 10, so the explanation will be omitted here.

[0146] <Solvent> The solvent may be alcohol (e.g., methanol, ethanol, propanol, isopropanol, etc.). propyl alcohol, n-butanol, s-butanol, t-butanol, benzyl alcohol, PGME, ethylene glycol, diacetone alcohol), ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, Tanone, diisobutyl ketone, diethyl ketone, diacetone alcohol), esters (acetic acid Methyl acetate, ethyl acetate, butyl acetate, n-propyl acetate, isopropyl acetate, methyl formate , PGMEA), aliphatic hydrocarbons (e.g., hexane, cyclohexane), halogenated hydrocarbons Hydrocarbons (e.g., methylene chloride, chloroform, carbon tetrachloride), aromatic hydrocarbons (e.g., benzene benzene, toluene, xylene), amides (e.g., dimethylformamide, dimethylacetamide ether (e.g., diethyl ether, dioxane, tetrahydrofuran, Ether alcohol (e.g., 1-methoxy-2-propanol), carbonyl alcohol (e.g., 1-methoxy-2-propanol), These solvents include dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. These may be used alone or in combination of two or more. In this case, components such as urethane (meth)acrylate and other additives are dissolved or dispersed. In addition, methyl isobutyl ketone and methyl ethyl ketone are preferred because they allow the resin layer composition to be suitably applied. Tons is preferred.

[0147] <Polymerization initiator> The polymerization initiator is decomposed by irradiation with ionizing radiation to generate radicals, which promote the polymerization of the polymerizable compound. It is a component that initiates or advances cross-linking.

[0148] A polymerization initiator is a substance that releases a radical polymerization initiator when exposed to ionizing radiation. There is no particular limitation as long as it is possible. The polymerization initiator is not particularly limited, and a known one may be used. Specific examples include acetophenones, benzophenones, Michler's compounds, and the like. Benzoyl benzoates, α-amyloxime esters, thioxanthones, propionyl Non-type compounds, benzil-type compounds, benzoin-type compounds, and acylphosphine oxide-type compounds. It is preferable to use a mixture of photosensitizers, and specific examples thereof include n-butyl aldehyde. amine, triethylamine, poly-n-butylphosphine, etc.

[0149] After forming a coating film of the resin layer composition, when the resin layer composition contains a solvent, various known The coating is heated to a temperature of, for example, 30°C or higher and 120°C or lower for 10 to 120 seconds. The mixture is dried by evaporating the solvent.

[0150] After drying the coating film, the coating film is irradiated with ionizing radiation such as ultraviolet light to harden it. The release film is peeled off to obtain the resin layer 10. The resin layer 10 satisfies the above-mentioned relational formula (1). However, such a resin layer 10 can be obtained not only by adjusting the composition of the resin layer composition, but also by For example, one side of the coating film is irradiated with ionizing radiation, and the irradiation conditions and / or Alternatively, it can be obtained by appropriately adjusting the type and amount of the polymerization initiator.

[0151] In addition, in the case of forming the optical film 30, after drying the coating film of the resin layer composition, The coating film is irradiated with ionizing radiation such as ultraviolet light to half cure it. "Semi-cured" in this context means that curing will proceed substantially upon further exposure to ionizing radiation. do.

[0152] Then, a functional layer 31 is formed on the semi-cured coating film by a coating device such as a bar coater. A functional layer composition for forming the functional layer is applied to form a coating film of the functional layer composition.

[0153] <<Composition for functional layer>> The composition for the functional layer contains a polymerizable compound. The composition for the functional layer may further contain other components as necessary. Depending on the application, ultraviolet absorbers, spectral transmittance adjusters, antifouling agents, inorganic particles, leveling agents, solvents, polymerization agents, etc. The solvent and the polymerization initiator may be the same as those in the resin layer composition. , and the description will be omitted here.

[0154] After forming a coating film of the composition for the functional layer, the coating film is heated, for example, at 30° C. or higher for 1 hour by various known methods. Dry by heating at a temperature below 20°C for 10 to 120 seconds to evaporate the solvent. do.

[0155] After drying the coating of the functional layer composition, the coating is irradiated with ionizing radiation such as ultraviolet light to completely coat the coating. The functional layer 31 is formed by hardening (fully curing). This means that further irradiation with ionizing radiation will not substantially advance the curing. The release film is peeled off to obtain the optical film 30.

[0156] When forming the optical film 50, for example, first, a mechanical The functional layer 52 is formed by the same method as the functional layer 31. Then, on the surface of the resin base material 51 opposite to the surface on which the functional layer 52 is formed, The resin layer 10 is formed in the same manner as above. In this manner, the optical film 50 can be obtained. Cut.

[0157] When the resin layer is a single-layer structure consisting of a soft resin layer with uniform hardness, the folding is excellent. However, since the resin layer is soft, the impact resistance is poor. When the resin is made into a single-layer structure consisting of a uniform hard resin layer, good impact resistance is obtained, but the resin The oil layer is hard, so it is difficult to fold. Also, the resin layer is made of a multi-layer structure of soft and hard layers. If the material is folded, peeling or cracking may occur at the interface between the soft and hard layers. Also, when folding, there is a risk of wrinkles occurring due to differences in deformation between the soft and hard layers. Based on these findings, the present inventors have developed a method for improving the folding property and the impact resistance on the surface of the optical film. When an impact is applied to the optical film, the surface of the optical film does not become dented, and the optical film in the image display device It has good impact resistance so that the internal components (e.g. polarizing plate) are not damaged. In order to obtain a resin layer having such a structure, the hardness of the resin layer having a single layer structure is changed from one side to the other side. According to the present embodiment, the resin having a single layer structure is The displacements d1 to d3 in the first region 10C to the third region 10E of the layer 10 are d1 <d2<d Since the above three relationships are satisfied, good foldability and good impact resistance can be obtained. do.

[0158] <<<Image display devices>>> The optical film 30 can be incorporated into a foldable image display device. FIG. 6 is a schematic diagram of an image display device according to this embodiment. As shown in FIG. The image display device 60 mainly includes a housing 61 that houses a battery and the like, a display, and a An element 62, a circular polarizing plate 63, a touch sensor 64, and an optical film 30 are laminated in this order. Between the housing 61 and the display element 62, between the display element 62 and the circular polarizing plate 63, Between the plate 63 and the touch sensor 64, and between the touch sensor 64 and the optical film 30, The transparent adhesive layer 65 and adhesive layer are disposed, and these members are The adhesive layer 65 is disposed between the housing 61 and the display element 62. Between the display element 62 and the circular polarizing plate 63, between the circular polarizing plate 63 and the touch sensor 64, The adhesive layer is disposed between the sensor 64 and the optical film 50. There are no particular limitations as long as it is between the room and the display element.

[0159] The optical film 30 is disposed so that the functional layer 31 is closer to the viewer than the resin layer 10. In the image display device 60, the surface 30A of the optical film 30 is 0 constitutes surface 60A.

[0160] In the image display device 60, the display element 62 is an organic light-emitting diode element or the like. The touch sensor 64 is disposed closer to the viewer than the circular polarizing plate 63. However, it may be disposed between the display element 62 and the circular polarizing plate 63. The touch sensor 64 may be of an on-cell type or an in-cell type. For example, OCA (Optical Clear Adhesive) can be used.

[0161] [Second embodiment] The optical film and the image display device according to the second embodiment of the present invention will be described below with reference to the drawings. The description will be given with reference to FIG. 7, which is a schematic diagram of the optical film according to this embodiment, and FIG. FIG. 8(A) and FIG. 8(B) are schematic diagrams showing the state of the folding static test.

[0162] <<<Optical films>>> The optical film 70 shown in FIG. 7 is foldable and has optical transparency. The optical film 70 has a front surface 70A and a back surface 70B opposite to the front surface 70A. The optical film 70 includes a resin substrate 71, a resin layer 72, and a hard coat. In the optical film 70, the resin layer 72 is thicker than the resin substrate 71. The hard coat layer 73 is provided on the back surface 70B side of the optical film 70. The optical film 70 is provided on the surface 70A side of the optical film 70. The mold 70 includes a hard coat layer 73, a resin substrate 71, and a back surface 70B. and a resin layer 72 in this order.

[0163] The optical film 70 is less likely to develop a crease even when subjected to a folding and static standing test. The folding static test and confirmation of folding habits are carried out as follows. The optical film 70 is cut into a size of 100 mm x 100 mm. In order to reproduce the above state, the cut optical film 70 is cut out and placed facing each other as shown in FIG. The area of ​​30 mm x 48 mm including the two short sides (30 mm) 70C and 70D is , respectively, are fixed to a glass plate 75 having a size of 50 mm x 100 mm. The optical film 70 is fixed to the rear surface 70B (resin layer 72 side) of the optical film 70. The film 70 is attached to the glass plate 2 so that the distance between the opposing sides 70C and 70D of the film 70 is 2.5 mm. 0 are arranged parallel to each other, and the optical film 70 is folded so that the surface 70A faces inward. The glass plate 75 is then left to stand at 25° C. for 100 hours. 70 is opened, and the surface of the optical film 70 is flattened as shown in FIG. In this state, it is visually confirmed whether or not the optical film 70 has a crease.

[0164] The optical film 70 is foldable in the same manner as the optical film 30. In the case of the film 70, for example, a folding test (continuous folding test) is performed on the optical film 70. Even after 100,000 repeated cycles, the optical film 70 does not crack or break. It is preferable that the optical fiber has a good optical fiber property even when the continuous folding test is repeated 200,000 times. It is more preferable that the film 70 does not crack or break, and it is tested for continuous folding 300,000 times. Even if the process is repeated, the optical film 70 does not crack or break. It is more preferable that the optical film 70 does not crack or crack even when the test is repeated 1 million times. It is most preferable that no breakage occurs during the continuous folding test. The test shall be carried out in the same manner as the continuous folding test. In this case, the distance φ between the two opposing sides is set to 20 mm, 10 mm, 6 mm, or 3 mm. Even when the optical film 70 was repeatedly folded 100,000 times, no cracks were observed in the optical film 70. It is more preferable that no breakage occurs. The smaller the distance between the two opposing sides, the better. I wish.

[0165] Another film such as a polarizing plate is provided on one side of the optical film 70 via an adhesive layer or bonding layer. If the product is folded, peel off the other films along with the adhesive layer before folding. Static tests and folding tests shall be conducted.

[0166] The surface 70A of the optical film 70 (the surface 73A of the hard coat layer 73) is JIS K5 Hardness measured by the pencil hardness test specified in 600-5-4:1999 (pencil hardness ) is preferably B or higher, more preferably H or higher. The pencil hardness test is The test is carried out in the same manner as the pencil hardness test described in the first embodiment.

[0167] The yellow index of the optical film 70 and the method for measuring it are the same as those of the optical film 50. The yellow index and its measuring method are the same as those of the optical film 70. The haze value, total light transmittance, and the measuring method thereof are The transmittance and the measuring method thereof are similar. The location is similar to the purpose, size and location of the optical film 30 .

[0168] <<Resin substrate>> The resin base material 71 is a base material containing a resin having optical transparency. The material of the resin base material 71 may be the same as that of the resin base material 51. If the thickness of the resin base material 71 is 20 μm or less, Since the thickness is small, the resin base material 71 does not stretch much when the optical film 70 is folded. The thickness of the resin substrate 71 can be measured in the same manner as the thickness of the resin layer 72. The upper limit of the resin base material 71 is 18 μm or less, 16 μm or less, from the viewpoint of reducing the amount of elongation. The lower limit of the resin base material 71 is preferably 1 μm or less, or more preferably 14 μm or less. From the viewpoint of ensuring a desired pencil hardness, it is 2 μm or more, 4 μm or more, or 6 μm or more. It is preferable.

[0169] The thickness of the resin base material 71 was measured by measuring the cross section of the functional layer 31 using a scanning transmission electron microscope (STEM). The cross section of the resin base material 71 is photographed in the same manner as the photographing of the surface. The film thickness of the resin base material 71 is measured at 10 points, and the arithmetic average value of the film thicknesses at the 10 points is determined.

[0170] The Berkovich indenter is pressed with a maximum load of 200 μN on the cross section of the resin substrate 71 in the thickness direction. When a pressing test was performed, the displacement d4 of the resin base material 71 was 50 nm or more and 250 nm or less. If the displacement d4 of the resin base material 71 is 50 nm or more, good bending properties are obtained. If the thickness is 250 nm or less, the desired pencil hardness can be ensured. The lower limit of the displacement d4 of 71 is set to 80 nm or more and 100 nm or less from the viewpoint of obtaining excellent bending properties. It is preferable that the displacement amount d4 of the resin base material 71 is 100 nm or more, or 110 nm or more. The limit is 220 nm or less, 200 nm or less, or It is more preferable that the displacement d4 of the resin base material 71 is measured by the following method. The displacements d1 to d3 of the resin layer 10 are measured in the same manner as described above. In order to avoid the influence of the side edge of the resin base material in the cross section in the thickness direction of the resin base material 71, The area is to be pressed into the center of the resin substrate at a distance of 500 nm or more from each side edge. .

[0171] <<Resin layer>> The resin layer 72 is a layer that contains a resin having optical transparency and has impact absorbing properties. The layer 72 is provided on the first surface 71A side of the resin substrate 71. In this embodiment, the resin layer 72 is adjacent to the first surface 71A of the resin base material 71.

[0172] The thickness of the resin layer 72 is 50 μm or more. If there is such a thickness, good impact resistance can be obtained. More preferably, the thickness of the resin layer 72 is 65 μm or more, or 70 μm or more. The limit is 120 μm or less, 110 μm or less, from the viewpoint of thinning and good processability. The thickness of the resin layer 72 is preferably 100 μm or less, or more preferably 100 μm or less. It shall be measured in the same manner as the thickness of 71.

[0173] The ratio of the thickness of the resin layer 72 to the thickness of the resin substrate 71 (thickness of the resin layer 72 / thickness of the resin substrate 71) The thickness of the sheet is between 4.0 and 12.0. If this ratio is 4.0 or more, the sheet has a folding habit. In addition, if this ratio is 12.0 or less, the desired The lower limit of this ratio is sufficient to obtain excellent bending resistance and excellent impact resistance. From the viewpoint of the above, it is more preferable that the ratio is 4.5 or more, 5.0 or more, or 6.0 or more. In order to obtain excellent flexibility, the limit is 11.0 or less, 10.0 or less, or 8.0 or less. It is preferable that there is.

[0174] The Berkovich indenter was pressed with a maximum load of 200 μN into the cross section of the resin layer 72 in the thickness direction. When a pressing test was performed, the displacement d5 of the resin layer 72 was 200 nm or more and 1500 nm or less. If the displacement d5 of the resin layer 72 is 200 nm or more, the desired flexibility can be obtained. If the thickness is less than 1500 nm, the required impact resistance test described later can be performed. The lower limit of the displacement d5 of the resin layer 72 is To further suppress overflow, 300nm or more, 400nm or more, or 500nm or more In addition, the upper limit of the displacement d5 of the resin layer 72 is preferably set to 100% or less in order to obtain excellent impact resistance. From the viewpoint of the wavelength, it is 1400 nm or less, 1200 nm or less, or 1100 nm or less. The resin layer of the present embodiment is softer and more viscous than the resin substrate and the hard coat layer. Since the influence of the nanoindentation method is large, the method of measuring the indentation hardness, etc. is not suitable. Therefore, the displacement amount is used as an index of hardness. is measured by the same method as the displacement d4 of the resin base material 71.

[0175] It is preferable that the ratio of the displacement amount d5 to the displacement amount d4 (d5 / d4) is 1.5 or more. If d5 / d4 is 1.5 or more, it is possible to suppress folding and improve impact resistance at the same time. In addition, the lower limit of d5 / d4 is set to 2.0 from the viewpoint of obtaining excellent bending suppression and excellent impact resistance. More preferably, the upper limit is 0 or more, 2.5 or more, or 3.0 or more. From the viewpoint of ensuring the stability, it is preferable that the value is 10.0 or less, 7.0 or less, or 5.0 or less. It is.

[0176] The resin constituting the resin layer 72 is selected so that the displacement d5 is 200 nm or more and 1500 nm or less. There is no particular limitation on the resin, so long as it is a resin that can be cured by ionizing radiation. Examples of the ionizing radiation curable compounds include cured products (polymerized products) of ionizing radiation-polymerizable compounds. Examples of hardened mixtures include urethane resins and acrylic gels. What is "gel"? Generally, it refers to a dispersion system that has high viscosity and has lost fluidity.

[0177] (Urethane resin) The urethane-based resin is the same as the urethane-based resin described in the section for the resin layer 10 .

[0178] (Acrylic gel) Acrylic gels include acrylic ester-containing molybdenum gels, which are used in adhesives, etc. Various polymers can be used as long as they are polymerized from monomers. Examples of acrylic gels include ethyl (meth)acrylate, n-propyl (meth)acrylate, ) acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate , i-Butyl (meth)acrylate, 2-Ethylhexyl (meth)acrylate, n-Hexyl Amyl (meth)acrylate, n-amyl (meth)acrylate, i-amyl (meth)acrylate Acrylate, Octyl (meth)acrylate, i-Octyl (meth)acrylate, i- Myristyl (meth)acrylate, lauryl (meth)acrylate, nonyl (meth)acrylate acrylate, i-nonyl (meth)acrylate, i-decyl (meth)acrylate, tridecyl Sil(meth)acrylate, stearyl(meth)acrylate, i-stearyl(meth)acrylate Polymerized or copolymerized acrylic monomers such as acrylates can be used. In this specification, the term "(meth)acrylate" includes both "acrylate" and "methacrylate". The term "acrylic acid" includes both "acrylic acid esters" and "acrylic acid esters" used in the above (co)polymerization. The esters may be used alone or in combination of two or more kinds.

[0179] <<Hard coat layer>> The hard coat layer 73 is provided on the second surface 71B side of the resin substrate 71. In the film 70, the hard coat layer 73 is adjacent to the second surface 11B of the resin substrate 11. In the present embodiment, the "hard coat layer" refers to a layer having a pencil hardness of 0.01 to 0.01 mm or less in the above-mentioned pencil hardness test. This refers to the layer where is "H" or higher.

[0180] A Berkovich indenter was applied to the cross section of the hard coat layer 73 in the thickness direction with a maximum load of 500 μN. When a pressing test was performed, the displacement d6 of the hard coat layer 73 was 500 nm or less. It is preferable that the displacement d6 of the hard coat layer 73 is 500 nm or less. If there is such a thickness, the desired pencil hardness can be ensured. The limit is 50 nm or more, 60 nm or more, or 70 nm or more from the viewpoint of ensuring bendability. The upper limit of the displacement d6 of the hard coat layer 73 is preferably 500 nm or less. , 490 nm or less, or 480 nm or less is more preferable. The displacement amount d6 of the resin substrate 71 is measured in the same manner as the displacement amount d4 of the resin substrate 71. The measurement conditions are as follows: (Measurement conditions) Control method: Load control (maximum load 500μN) Lift amount: 0nm Preload: 0.5μN ·Loading speed: 20μN / sec ·Holding time: 5 seconds ·Loading and unloading speed: 20μN / sec ·Measurement temperature: 23±5℃ Relative humidity: 30%~70%

[0181] The thickness of the hard coat layer 73 is preferably 3 μm or more and 10 μm or less. If the thickness of the hard coat layer 73 is 3 μm or more, a good hardness can be obtained. If the thickness is 10 μm or less, deterioration of processability can be suppressed. When the hard coat layer has a multi-layer structure, the thickness of each hard coat layer is The lower limit of the thickness of the hard coat layer 73 is 5 It is more preferable that the upper limit is 8 μm or less. The thickness of the hard coat layer 73 is measured in the same manner as the thickness of the resin substrate 71. .

[0182] The hard coat layer 73 further contains a resin and inorganic particles dispersed in the resin. The resin and inorganic particles of the hard coat layer 73 are preferably the same as those described in the functional layer 31. The same applies to the resins and inorganic particles used.

[0183] The hard coat layer 73 may contain materials other than those mentioned above as long as the above-mentioned displacement amount is satisfied. For example, the resin component may be a material that forms a hardened product by irradiation with ionizing radiation. The polymerizable monomer and the polymerizable oligomer may be included. The polymerizable oligomer is a polymerizable monomer or a polymerizable oligomer described in the functional layer 31 column. Same as Ma.

[0184] <<<Optical film manufacturing method>>> The optical film 70 can be produced as follows. A composition for a hard coat layer is applied onto the second surface 71B using a coating device such as a bar coater. Thus, a coating film of the composition for a hard coat layer is formed.

[0185] <Hard Coat Layer Composition> The composition for the hard coat layer contains a polymerizable compound. In addition, if necessary, ultraviolet absorbers, spectral transmittance adjusters, antifouling agents, inorganic particles, levelin The solvent and the polymerization initiator may be the same as those in the first embodiment. The solvent and the polymerization initiator are the same as those described in the section on the resin layer composition.

[0186] After forming a coating film of the composition for a hard coat layer, the coating film is dried for, for example, 30 minutes by various known methods. Dry the film by heating it at a temperature of 10 to 120°C for 10 to 120 seconds to remove the solvent. Allow to evaporate.

[0187] After drying the coating film of the composition for the hard coat layer, the coating film is irradiated with ionizing radiation such as ultraviolet rays to form a The film is cured to form a hard coat layer 73 .

[0188] After the hard coat layer 73 is formed, the first surface 71A of the resin substrate 71 is coated with a bar coater. A resin layer composition for forming the resin layer 72 is applied by a coating device such as a coating machine. A coating of the layer composition is formed. The coating is then cured to form the resin layer 72. do.

[0189] <Composition for resin layer> When the resin layer 72 is made of a urethane-based resin, for example, the resin layer composition may be The ionizing radiation curable urethane resin composition described in the section on urethane resins can be used. .

[0190] After forming a coating film of the resin layer composition, when the resin layer composition contains a solvent, various known methods are used. The coating is heated to a temperature of, for example, 30°C or higher and 120°C or lower for 10 to 120 seconds. The mixture is dried by evaporating the solvent.

[0191] After the coating is dried, it is irradiated with ionizing radiation such as ultraviolet light to harden it. Thus, the resin layer 12 is formed, and the optical film 70 can be obtained.

[0192] Folding occurs when the inner or outer surface of the resin substrate is stretched when the optical film is folded. This causes the resin base material to exceed its elastic limit, resulting in plastic deformation. Therefore, if the resin substrate is made thin, the optical film can be folded without any problems. The stretching of the resin substrate can be suppressed. However, if the resin substrate is made thin, the impact resistance decreases. On the other hand, when the indentation test was performed, the displacement was 200 nm or more and 1500 nm or less. The resin layer has a wider elastic region than the resin substrate, so it is less susceptible to plastic deformation and is less susceptible to breakage. Also, if the resin layer is too thin, the impact resistance will decrease. , and a good condition that the surface of the optical film does not become dented when an impact is applied to the surface of the optical film. In order to obtain sufficient impact resistance, a certain film thickness is required. According to the JIS Z 2011-1001, the thickness is 20 μm or less, and the displacement d4 during the indentation test is 50 When an indentation test was performed on the first surface 71A side of the resin substrate 71 having a thickness of 250 nm or more, A resin layer 72 having a displacement d5 of 200 nm or more and 1500 nm or less is provided, and a resin substrate 7 The thickness of the resin layer 72 is set to 50 μm or more, and the thickness of the resin substrate 71 is set to 20 μm or less. The ratio of the thickness of the resin layer 72 to the thickness of the optical filter is set to 4.0 or more and 12.0 or less. When the folding member 70 is folded, it is difficult for it to develop a crease, and good impact resistance can be obtained.

[0193] <<<Image display devices>>> The optical film 70 can be incorporated into a foldable image display device. The structure of the image display device incorporating the optical film 70 is similar to that of the optical film 30. The structure of the image display device is the same as that of the image display device 60, except that the optical film 70 is incorporated in the

[0194] [Third embodiment] The optical film and the image display device according to the third embodiment of the present invention will be described below with reference to the drawings. The description will be given with reference to FIG. 9, which is a schematic diagram of the optical film according to the present embodiment. FIG. 10 is a partially enlarged view of the optical film of FIG. 9, and FIG. 11 is another optical film according to this embodiment. FIG.

[0195] <<<Optical films>>> The optical film 80 shown in FIG. 9 is used in an image display device and is foldable. It is possible.

[0196] As shown in FIG. 9, the optical film 80 is made of a resin base material 81 and a The optical film 80 further includes a resin layer 82 provided on the first surface 81A side. The resin layer 82 further includes a functional layer 85 provided on a surface 82A of the resin layer 82. The "resin layer" in this specification means a layer containing a resin, and may have a single-layer structure, but may have a multilayer structure of two or more layers. The resin layer 82 may have a multi-layer structure of two or more layers, specifically, a two-layer structure, as described below. The functional layer 85 has a single-layer structure. However, it may have a multi-layer structure of two or more layers.

[0197] The surface 80A of the optical film 80 is an uneven surface. The surface 80A of the optical film 80 is the surface 85A of the functional layer 85. 80B is the second surface 81B of the resin base material 81, which is opposite to the first surface 81A.

[0198] The optical film 80 is foldable in the same manner as the optical film 30. In the case of the film 80, for example, a folding test (continuous folding test) is performed on the optical film 80. Even when repeatedly performed 100,000 times, the optical film 80 does not crack or break. It is preferable that the optical fiber has a good optical fiber property even when the continuous folding test is repeated 200,000 times. It is more preferable that the film 80 does not crack or break, and it is tested for continuous folding 300,000 times. Even if the process is repeated, the optical film 80 does not crack or break. It is more preferable that the optical film 80 does not crack or crack even when the test is repeated 1 million times. It is most preferable that no break occurs. The continuous folding test is performed by dividing the distance between two opposing sides. Except for the diameter being 8 mm, the same method as the continuous folding test described in the first embodiment was used. In the optical film 80, the distance φ between the two opposing sides is set to 6 The test was repeated 100,000 times with the thickness set to 1 mm, 4 mm, or 2 mm. However, it is more preferable that the optical film 80 does not crack or break.

[0199] The surface 80A of the optical film 80 (the surface 85A of the functional layer 85) is made of #0000 steel. Steel wool (product name: Bonstar, manufactured by Nippon Steel Wool Co., Ltd.) was used for a 1kgf / cm 2 When a scratch resistance test was conducted in which the material was rubbed back and forth 10 times at a speed of 60 mm / sec while applying a load of 100 mm, no scratches were observed. The above test was performed on an optical fiber cut to a size of 50 mm x 100 mm. Place the film on the glass plate using Nichiban Cellophane Tape (registered trademark) to prevent any creases or folds. The optical film was fixed in place with the surface facing up and the temperature was 23±5°C and the relative humidity was The above scratches are on the opposite side of the optical film. Black vinyl tape (Yamato Corporation's black vinyl tape NO200-38) on the glass surface -21) is affixed and can be seen visually under a three-wavelength fluorescent lamp.

[0200] The yellow index of the optical film 80 and the method for measuring it are the same as those of the optical film 50. The yellow index and its measuring method are the same. The total light transmittance and its measuring method are similar to those of the resin layer 10 . The use, size and location of the optical film 80 are the same as those of the optical film 30. and placement location are the same.

[0201] The haze value (total haze value) of the optical film 80 is preferably 20% or less. If the haze value of the film 80 is 20% or less, the optical film 80 can be attached to a mobile terminal. When used, the whitening of the image display surface can be suppressed. The lower limit of the haze value is 1% or more. and the upper limit is preferably 15% or less, 10% or less, or 5% or less. The haze value of the optical film 80 is measured in the same manner as the haze value of the resin layer 10. be.

[0202] The transmitted image clarity of the optical film 80 is 40% or more at 0.125 mm comb (comb A). It is preferable that the ratio is 90% or less for the 2.0 mm comb (comb B) and 80% or more for the 2.0 mm comb (comb B). If the transmitted image clarity at 125mm comb (comb A) is 40% or more, the glare (spark) The clearness of the transmitted image at the 0.125 mm comb (comb A) can be suppressed. If the ratio is 90% or less, the pressure marks can be made less noticeable. If the transmitted image clarity in (Comb B) is 80% or more, the image can be clearly viewed. The lower limit of the transmitted image clarity in the 0.125 mm comb (comb A) is 45% or more, and 50% or more. The upper limit is preferably 85% or less. In addition, the lower limit of the transmitted image clarity in the above 2.0 mm comb (comb B) is 90% or more. It is more preferable to do so.

[0203] The above transmitted image clarity is measured under conditions of temperature 23±5℃ and relative humidity 30% to 70%. Then, using an image clarity measuring instrument (for example, product name "ICM-IT", manufactured by Suga Test Instruments Co., Ltd.) It can be measured by a method conforming to the transmission method of image clarity of JIS K7374:2007. The above transmitted image clarity was measured by cutting the optical film into a size of 50 mm x 100 mm. After that, the image clarity measurement was performed with the setting of transmission measurement in a state where there were no curls or wrinkles, and no fingerprints or dust, etc. Place the resin substrate in the container so that it faces the light source, and measure three times for each optical comb. If the optical film cannot be cut to the above size, For example, the opening of the sample stage for the ICM-1T is 25 mm in diameter, so The sample size must be at least 26 mm in diameter. For this reason, the sample size must be 27 mm x 27 mm. The optical film may be cut into pieces of 1 mm or more. If the light source spot is not visible, try moving it a little at a time or changing the angle. Measurement points are set at three locations.

[0204] The surface 80A of the optical film 80 is an uneven surface. The irregularities that make up A are the average interval Sm, the average inclination angle θa, the arithmetic mean roughness Ra, and the maximum height When the roughness is Ry, it is preferable that the following relationship is satisfied. 0.15mm≦Sm≦0.5mm 0.02°≦θa≦0.50° 0.01μm≦Ra≦0.15μm 0.10μm≦Ry≦0.50μm

[0205] If the average interval Sm is 0.15 mm or more, the cloudiness of the image can be suppressed. If it is 0.5mm or less, glare (sparkle) can be suppressed. The lower limit of Sm is 0.2 0 mm or more, or 0.22 mm or more is more preferable, and the upper limit is 0.45 mm or more. It is more preferable that the thickness is 0.40 mm or less.

[0206] If the average inclination angle θa is 0.02° or more, the pressure mark can be made less noticeable. Furthermore, if θa is 0.05° or less, the cloudiness of the image can be suppressed. More preferably, the angle is 0.04° or more, or 0.06° or more, and the upper limit is 0.30° or less. Or, it is more preferable that it is 0.20° or less.

[0207] The arithmetic mean roughness Ra is preferably 0.01 μm or more and 0.15 μm or less. If Ra is 0.01 μm or more, the pressure marks can be made less noticeable. If Ra is 0.15 μm or less, the visibility of the image can be improved. is more preferably 0.03 μm or more or 0.05 μm or more, and the upper limit is 0. It is more preferable that the thickness is 12 μm or less, or 0.10 μm or less.

[0208] The maximum height roughness Ry is preferably 0.10 μm or more and 0.80 μm or less. If Ry is 0.10 μm or more, the pressure mark can be made less noticeable. If Ry is 0.50μm or less, glare (sparkle) can be suppressed. The lower limit of Ry is , more preferably 0.15 μm or more or 0.20 μm or more, and the upper limit is 0.6 It is more preferable that the thickness is 0 μm or less or 0.40 μm or less.

[0209] The definitions of "Sm", "Ra" and "Ry" above are in accordance with JIS B0601:1994. The definition of "θa" is based on the surface roughness measurement instrument Surfcorder SE-3400 ( The instruction manual (revised on July 20, 1995) of Kosaka Laboratory Co., Ltd. must be followed. θa is expressed by the following formula (A). θa=tan -1 Δa …(A) In formula (A), Δa is the slope expressed as the aspect ratio, and is the difference between the minimum and maximum points of each concavo-convex. (corresponding to the height of each convexity) divided by the reference length.

[0210] Sm, Ra, Ry and θa are all measured using, for example, a Surfcorder SE-3400, S Measure using E-3500 or SE-500 (both manufactured by Kosaka Laboratory Co., Ltd.) Here, even if θa cannot be measured directly, Δa can be measured. If possible, θa and Δa are related by the above formula (A), so Δa is measured. It is possible to obtain θa from the measured Δa. The off wavelength is set to 0.8 mm in all cases.

[0211] On the front side of the optical film 80, another film such as a polarizing plate is provided via an adhesive layer or a bonding layer. If the film is folded, peel off the adhesive layer and other films before folding. , Yellow index measurement, Total light transmittance measurement, Haze value measurement, Transmitted image clarity, Average The intervals are Sm, etc.

[0212] The resin base material 81 is a base material containing a resin having optical transparency. The material is the same as that of the resin base material 51. The thickness of the resin base material 81 is 10 μm or more. It is preferable that the thickness of the resin base material 81 is 10 μm or more. In addition, the optical film can be prevented from curling, and sufficient hardness can be obtained. Even when manufacturing Room 80 by roll to roll method, wrinkles are less likely to occur. On the other hand, if the thickness of the resin base material 81 is 100 μm or less, The folding performance of the optical film 80 is good and meets the requirements of the continuous folding test. This is also preferable in terms of reducing the weight of the optical film 80. A cross section of the resin substrate 81 is photographed using a scanning electron microscope (SEM), and the cross section is The film thickness of the resin base material 81 is measured at 10 points, and the arithmetic average value of the film thicknesses at the 10 points is determined. The lower limit of the resin base material 81 is preferably 25 μm or more, 30 μm or more, or 35 μm or more. More preferably, the upper limit of the resin base material 81 is 80 μm or less, 75 μm or less, or 70 μm or less. It is more preferable that there is.

[0213] <<Resin layer>> The resin layer 82 has an uneven surface 82A. This is because the organic particles 83B described later The Sm, θa, Ry, and Rz of the irregularities constituting the surface 82A are It is preferable that Sm, θa, Ry, and Rz of the projections and recesses constituting A are in the same ranges. The unevenness Sm etc. constituting the surface 82A is formed in the same manner as the unevenness Sm etc. constituting the surface 80A. It can be measured by:

[0214] The resin layer 82 functions as a hard coat layer. In addition to the hard coat property, the hard coat layer may have a function other than the hard coat property. The hard coat layer is the indentation hardness (H IT )but In this specification, the term "indentation hardness" refers to a layer having an indentation hardness of 150 MPa or more. The "strength" is a value obtained from the load-displacement curve from loading to unloading the indenter. The indentation hardness is the arithmetic average of the values ​​measured at 10 points. The method for measuring the hardness is described in detail below.

[0215] The indentation hardness of the lower portion 82B of the resin layer 82 is It is preferable that the hardness is smaller than the dentation hardness of the lower portion 82B of the resin layer 82. The indentation hardness of the upper portion 82C of the resin layer 82 is smaller than the indentation hardness of the upper portion 82C of the resin layer 82. If the resin layer 82 is soft, the organic particles 83B described later will be present in the soft portion of the resin layer 82. The optical film 80 is less likely to crack when heated, and the organic particles 83B are more likely to adhere to the surface 82A. Since there is a hard portion on the side, a superior surface hardness can be obtained.

[0216] The indentation hardness (H IT ) Measurements are taken by BRUKER This will be performed using a Bruker TI950 TriboIndenter. Specifically, first, an optical film cut to 1 mm x 10 mm is embedded in embedding resin. A block was prepared, and a uniform section without holes was cut from this block using a general sectioning method. Sections with a thickness of 70 nm to 100 nm are cut out. The ultramicrotome EM UC7 from Ka Microsystems Co., Ltd. can be used. The remaining block from which the uniform slices without holes were cut is then used as a measurement sample. Then, the above-mentioned slice is cut out from the measurement sample. The cross section obtained by the above measurement was measured using a Berkovich indenter under the following measurement conditions: vich) Place an indenter (triangular pyramid, BRUKER TI-0039) on the bottom cross section of the resin layer for 1 The specimen is then pressed vertically up to a maximum load of 50 μN over a period of 0 seconds. Here, the Berkovich indenter is In order to avoid the influence of the resin substrate and the side edge of the resin layer, the resin substrate and the resin layer are The resin layer is 500 nm away from the interface of the resin layer toward the center of the resin layer, and the resin layer is 500 nm away from both ends of the resin layer. The specimen shall be pushed into the area 500 nm or more away from the center of the specimen. After that, the specimen shall be held for 5 seconds, and then The load is removed over 0 seconds. The maximum pressing load P max and the contact projection area A p Using and, P max / A p The indentation hardness (H IT ) is calculated. The standard sample was fused silica (BRUKER 5-0098) and the Oliver-P The contact projected area is corrected for the indenter tip curvature using the harr method. Indentation hardness (H IT ) is the arithmetic average of the values ​​obtained by measuring at 10 points. If any measurement value is outside the average by ±20% or more, the measurement value is excluded and remeasured. Whether any of the measured values ​​deviate from the arithmetic mean by ±20% or more is determined. If the measured value is A and the arithmetic mean value is B, the difference is calculated by (AB) / B×100. The judgment shall be made based on whether the value (%) that can be determined is ±20% or more. The indentation hardness is also measured in the same manner as the indentation hardness of the lower part of the resin layer. However, in this case, the Berkovich indenter is influenced by the functional layer and the side edge of the resin layer in the upper part of the resin layer. In order to avoid this, the resin layer and the functional layer must be spaced apart from each other by 500 nm toward the center of the resin layer. The layer is pressed into the area 500 nm or more away from each end of the layer toward the center of the resin layer. do. (Measurement conditions) Control method: Load control method ·Loading speed: 5μN / sec ·Holding time: 5 seconds ·Loading and unloading speed: 5μN / sec ·Temperature: 23℃~25℃ Relative humidity: 30%~70%

[0217] The thickness of the resin layer 82 is preferably 2 μm or more and 15 μm or less. If the thickness of 2 is 2 μm or more, a sufficient hardness as a hard coat layer can be obtained. In addition, if the thickness is 15 μm or less, deterioration of processability can be suppressed. "Film thickness" refers to the total thickness of each resin layer (when the resin layer has a multi-layer structure). The lower limit of the resin layer 82 is 3 μm or more, 4 μm or more, or 5 The upper limit of the thickness of the resin layer 82 is preferably 12 μm or less, more preferably 10 μm or less. , or more preferably 8 μm or less.

[0218] The thickness of the resin layer 82 is measured by a scanning transmission electron microscope (STEM) or a transmission electron microscope ( The cross section of the resin layer 12 was photographed by a TEM in the same manner as the cross section of the functional layer 31. The cross-sectional image was photographed, and the thickness of the resin layer 82 was measured at 10 points in the cross-sectional image. The arithmetic average value of the film thickness is used. Note that the resin base material 81 is formed between the resin base material 81 and the resin layer 82. In some cases, a mixed layer containing the component that constitutes the resin layer 82 and the component that constitutes the resin layer 82 may be present. The thickness of the second layer is not included in the thickness of the resin layer.

[0219] The resin layer 82 contains organic particles 83B, which will be described later. 10, which is a virtual line that bisects the resin layer 82 in the thickness direction D2. The organic particles 83B are unevenly distributed on the resin base material 81 side. The organic particles 83B are closer to the resin base material 81 side than the center line CL. Whether or not the particles are unevenly distributed can be confirmed using a scanning transmission electron microscope (STEM) or a transmission electron microscope (T The center of each organic particle 83B was obtained from a cross-sectional photograph of the resin layer 12 taken by EM. By determining whether the average position of the center is on the resin base material 81 side from the center line CL, Specifically, first, in the same manner as in the measurement of the thickness of the resin layer 82, a scanning transmission electron microscope (STEM) A cross section of the resin layer 82 is photographed using a scanning electron microscope (STEM) or a transmission electron microscope (TEM). The film thickness of the resin layer 82 is measured for each cross-sectional photograph. The position of the center line CL is obtained in each cross-sectional photograph. The center of the particle 83B is determined. The center is the closest to the resin substrate of the organic particle in the thickness direction of the resin layer. The distance can be calculated by finding the midpoint of the imaginary line segment that connects the closest point and the farthest point. In each cross-sectional photograph, the distance between the center of the organic particle 83B and the center line CL is At this time, the center of the organic particle 83B is located below the center line CL (on the resin substrate 81 side). When the organic particle 83B is located at the center line CL, the distance between the center of the organic particle 83B and the center line CL is set to "-". The distance between the center of the organic particle 83B and the center line CL when the organic particle 83B is located on the upper side (the functional layer 85 side) is defined as Then, by calculating the average of these distances, the average position of the center of organic particle 83B is calculated. Therefore, depending on whether the average position is "-" or "+", This determines whether or not the defect is present on the resin base material 81 side relative to the position of the center line CL.

[0220] The ratio of the average particle size of the organic particles 83B to the thickness of the resin layer 82 (average particle size / film thickness) is 0. It is preferable that the ratio is 1 or more and 1 or less. If the ratio is 0.1 or more, the desired unevenness can be provided. If the ratio is 1 or less, the organic particles 83B are arranged to divide the resin layer 82 into two equal parts in the thickness direction D2. The organic particles 83B can be easily distributed on the resin base material 11 side from the center line CL. Particle size was measured using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). The particle sizes of 20 organic particles were calculated from cross-sectional images of organic particles taken at magnifications of 5,000 to 20,000. The particle size of 20 organic particles is measured and the arithmetic mean value is used. The particle size of organic particles is measured as follows: First, the long and short diameters are measured, and the individual diameters are calculated from the average of the long and short diameters. Calculate the particle diameter of the particles. Here, the major axis is the longest diameter of each particle on the screen. The minor axis is determined by drawing a line segment perpendicular to the midpoint of the line segment that constitutes the major axis. It is the distance between the two points where the particle intersects.

[0221] The resin layer 82 is made up of a first resin layer 83 and a second resin layer 84 provided on the surface 82A side of the first resin layer 83. 10, the first resin layer 83 and the second resin layer 84 are Since the thicknesses of the first and second resin layers 83 and 84 are equal, the center line CL is exists nearby.

[0222] <First resin layer> The first resin layer 83 contains a binder resin 83A and organic particles 83B. By incorporating organic particles 83B into the resin layer 82, the surface 82A of the resin layer 82 is made uneven. It is preferable that the first resin layer 83 further contains inorganic particles 83C. By including inorganic particles 83C in the resin layer 83, it is easy to control the uneven shape. The layer 83 may contain, in addition to the binder resin 83A, etc., as necessary, to the extent that the effect of the present invention is not impaired. For example, ultraviolet absorbers, adhesion improvers, leveling agents, thixotropy agents, coupling agents, etc. The composition may contain additives such as a binder, a plasticizer, an antifoaming agent, a filler, a colorant, etc.

[0223] The indentation hardness of the first resin layer 83 is equal to the indentation hardness of the second resin layer 84. It is preferable that the indentation hardness of the first resin layer 83 is smaller than the indentation hardness of the first resin layer 83. If the indentation hardness is smaller than that of the second resin layer 84, the organic particles 83B are soft. Since the insulating layer 83 is located in the first resin layer 83, the optical film 80 is less likely to crack when folded. In both cases, the second resin layer 84, which is harder, is present closer to the surface 82A than the organic particles 83B. Excellent surface hardness can be obtained.

[0224] The indentation hardness of the first resin layer 83 is 150 MPa or more and 350 MPa or less. It is preferable that the indentation hardness of the first resin layer 83 is 150 MPa or more. If the first resin layer 83 has a good pencil hardness, the indentation hardness of the first resin layer 83 can be set to If the elastic modulus is 350 MPa or less, good bending properties can be obtained. The lower limit of the axial hardness is 180MPa or more, 200MPa or more, or 220MPa or more. More preferably, the upper limit is 330 MPa or less, 300 MPa or less, or It is more preferable that the indentation strength of the first resin layer 83 is 280 MPa or less. The hardness was measured in the same manner as the indentation hardness of the lower portion 82B of the resin layer 82. Measurement shall be carried out under specified conditions.

[0225] (binder resin) The binder resin 83A includes a polymer (hardened product) of a polymerizable compound (hardenable compound). The polymerizable compound has at least one polymerizable functional group in the molecule. The polymerizable compound is a polymerizable functional group and a polymerizable compound described in the functional layer 31 column. It is the same as

[0226] (organic particles) The organic particles 83B are particles mainly composed of organic components. In addition, inorganic components may be mixed. As organic particles, polymethyl methacrylate Particles, polyacrylic-styrene copolymer particles, melamine resin particles, polycarbonate particles , polystyrene particles, cross-linked polystyrene particles, polyvinyl chloride particles, benzoguanamine- Melamine formaldehyde particles, silicone particles, fluorine-based resin particles, polyester resin particles Examples include fat particles.

[0227] The organic particles 83B are spherical in shape, so that it is easy to control the shape of the unevenness. In the present specification, the term "spherical" includes, for example, a perfect sphere, an oval sphere, etc. However, this does not include so-called amorphous objects.

[0228] The average particle size of the organic particles 83B is preferably 0.5 μm or more and 10 μm or less. If the average particle size of the organic particles 83B is within this range, it is easy to control the shape of the desired irregularities. The lower limit of the average particle size of organic particles is 1.0 μm or more or 1.5 μm or more. Preferably, the upper limit is 8 μm or less, 6 μm or less, or 4 μm or less.

[0229] (Inorganic particles) The inorganic particles 83C are particles that mainly contain inorganic components. The average particle size of the inorganic particles 83C is 1 It is preferable that the average particle size of the inorganic particles 83C is 1 nm or more and 50 nm or less. If so, it is easy to control the uneven shape, and if the average particle size of inorganic particle 83C is 50 nm or less, By using this method, the light diffusion caused by the inorganic particles 83C can be suppressed, and excellent contrast can be obtained. The lower limit of the average particle size of inorganic particles 83C is 3 nm or more, 5 nm or more, or 7 nm or more. It is preferable that the upper limit is 40 nm or less, 30 nm or less, or 20 nm or less. The average particle size of the inorganic particles 83C is preferably measured by a transmission electron microscope (TEM) or a scanning electron microscope (STEM). Cross-sections of inorganic particles photographed at magnifications of 50,000 to 200,000 using a scanning electron microscope (STEM). The particle sizes of 20 inorganic particles are measured from the image, and the arithmetic mean value of the particle sizes of the 20 inorganic particles is calculated. .

[0230] The content of the inorganic particles 83C in the first resin layer 83 is the same as that in the second resin layer 84, which will be described later. The content of inorganic particles 83C is less than the content of inorganic particles 84B. By making the amount of the first resin layer 83 smaller than that of the second resin layer 84, This can be done.

[0231] The inorganic particles 83C are not particularly limited, but may be, for example, silica (SiO2) fine particles, Alumina particles, titania particles, tin oxide particles, antimony-doped tin oxide (abbreviation: ATO ) particles, zinc oxide particles, and other inorganic oxide particles.

[0232] When silica particles are used as inorganic particles 83C, among silica particles, those with smooth particles that are easy to dissolve are From the viewpoint of forming a resin layer 82 having an uneven surface, fumed silica particles are preferred. Fumed silica is an amorphous material having a particle size of 200 nm or less produced by a dry method. It is a type of silica that can be obtained by reacting volatile compounds containing silicon in the gas phase. Specifically, for example, silicon compounds such as silicon tetrachloride (SiCl4) can be reacted with oxygen and water. Examples include those produced by hydrolysis in a flame. Examples of such a rubber include AEROSIL (registered trademark) R805 manufactured by Nippon Aerosil Co., Ltd. can be.

[0233] When inorganic oxide particles are used as inorganic particles 83C, the inorganic oxide particles are amorphous. This is because, when the inorganic oxide particles are crystalline, the inorganic oxide particles are preferably included in the crystal structure. Due to lattice defects, the Lewis acid salt of inorganic oxide particles becomes strong, and the inorganic oxide particles are over-excited. This is because there is a risk that the degree of aggregation will become uncontrollable.

[0234] In addition, when fumed silica particles are used as the inorganic particles 83C, the fumed silica particles There are hydrophilic and hydrophobic molecules, and among these, the amount of water absorption is From the viewpoint of reducing the amount of the hydrophobicity and facilitating dispersion in the resin layer composition, it is preferable to use a hydrophobic material. Hydrophobic fumed silica is characterized by the silanol groups present on the surface of the fumed silica particles. The above-mentioned surface treatment agent can be used to chemically react with the above-mentioned surface treatment agent.

[0235] The inorganic particles 83C preferably have a spherical shape in the single particle state. Since the single particles have such a spherical shape, the optical film can be used on the image display surface of an image display device. When the lens is positioned in the vertical direction, an image with better contrast can be obtained.

[0236] <Second resin layer> The second resin layer 84 contains a binder resin 84A and inorganic particles 84B. By including inorganic particles 84B in the resin layer 82, the hardness of the resin layer 82 can be improved. The second resin layer 84 does not contain organic particles. In addition to A, etc., if necessary, for example, an ultraviolet absorber, a bonding agent, etc. may be added within a range that does not impair the effects of the present invention. Adhesion improver, leveling agent, thixotropy agent, coupling agent, plasticizer, defoamer, filler The ink may contain additives such as colorants.

[0237] The indentation hardness of the second resin layer 84 is 250 MPa or more and 450 MPa or less. It is preferable that the indentation hardness of the second resin layer 84 is 250 MPa or more. If the second resin layer 84 is made of a fluororesin, it is possible to obtain good pencil hardness and scratch resistance, and the indentation of the second resin layer 84 is prevented. If the bending hardness is 450 MPa or less, good bending properties can be obtained. The lower limit of the indentation hardness of the layer 84 is 270 MPa or more, 300 MPa or more, or More preferably, the upper limit is 320 MPa or more, and the upper limit is 420 MPa or less, and 400 The insulator layer 84 is preferably 370 MPa or less, more preferably 370 MPa or less. The dentation hardness was measured in the same manner as the indentation hardness of the upper portion 82C of the resin layer 82. and similar measurement conditions.

[0238] (binder resin) The binder resin 84A includes a polymer (cured product) of a polymerizable compound (curable compound). The synthetic compound is preferably a polyfunctional (meth)acrylate. As the related compound, the polyfunctional (meth)acrylate in the binder resin column of the first resin layer 13 is used. The binder resin may be a polyfunctional (meth)acrylate. In addition, polyfunctional urethane (meth)acrylate, polyfunctional epoxy (meth)acrylate and and / or reactive polymers, etc.

[0239] (Inorganic particles) The inorganic particles 84B are the same as the inorganic particles described in the functional layer 31 section.

[0240] <<Functional Layer>> The surface 85A of the functional layer 85 reflects the unevenness of the surface of the resin layer 82. The functional layer 85 may be a single layer, or may have a multi-layer structure of two or more layers. For example, the antifouling layer may have a laminated structure of an inorganic layer and an antifouling layer. This can prevent fingerprints and the like from being left on the surface.

[0241] (Inorganic layer) The inorganic layer is a layer mainly composed of an inorganic substance. For example, the inorganic substance in the inorganic layer is 55% by mass. % or more, it is considered to be an inorganic layer. It is preferable that the layer is made of only organic materials. Whether or not the layer is an inorganic layer can be determined by X-ray photoelectron spectroscopy. X-Ray Photoelectron Spectroscopy:XP S or Electron Spectroscopy for Chemical A This can be confirmed by ESCA.

[0242] The inorganic layer may be made of metals such as Ti, Al, Mg, or Zr, or silicon oxide (S iO x (x=1 to 2)), aluminum oxide, silicon oxynitride, aluminum oxynitride, Inorganic oxides such as magnesium oxide, zinc oxide, indium oxide, tin oxide, and yttrium oxide Examples of such materials include inorganic oxides, inorganic nitrides, and diamond-like carbon. From the viewpoint of improving the adhesion rate and scratch resistance, silicon oxide is preferred.

[0243] The inorganic layer preferably contains Si atoms. By containing Si atoms, the inorganic layer Whether or not the inorganic layer contains Si atoms can be determined by X-ray photoelectron spectroscopy. X-Ray Photoelectron Spectroscopy (XPS) or Electron Spectroscopy for Chemical Analysis This can be confirmed by ESCA (electron microscopy).

[0244] The thickness of the inorganic layer is preferably 10 nm or more and 300 nm or less. If the film thickness is 10 nm or more, excellent scratch resistance can be imparted. If the thickness is less than 100 nm, the adhesiveness to other layers is good without affecting the flexibility or optical properties. The lower limit of the thickness is more preferably 30 nm or more, 50 nm or more, or 80 nm or more. More preferably, the upper limit is 250 nm or less, 200 nm or less, or 150 nm or less. The thickness of the inorganic layer is determined in the same manner as the thickness of the resin layer 82.

[0245] The inorganic layer can be formed by using, for example, a vapor deposition method such as a PVD method or a CVD method. Examples of the PVD method include vacuum deposition, sputtering, and ion plating. Examples of the vacuum deposition method include the electron beam (EB) heating method. Examples of the method include a vacuum deposition method using a high-frequency dielectric heating system, and a vacuum deposition method using a high-frequency dielectric heating system.

[0246] (Anti-stain layer) The antifouling layer may have water and oil repellency, so that the resulting optical film 80 can be There are no particular limitations on the material as long as it can impart antifouling properties, but the material to be coated is preferably a fluorine-containing organosilicon compound. It is preferable that the protective layer is a fluorine-containing organosilicon compound layer obtained by curing a film.

[0247] The thickness of the antifouling layer is not particularly limited, but the antifouling layer may be a layer of a fluorine-containing organosilicon compound. In this case, the thickness of the antifouling layer is preferably 1 nm or more and 20 nm or less. If the thickness is 1 nm or more, the inorganic layer is uniformly covered with the antifouling layer, and the antifouling layer has a scratch resistance. From the viewpoint of practical use, if the thickness of the antifouling layer is 20 nm or less, the antifouling layer is formed. The optical properties such as the haze value of the optical film in the formed state are good. The limit is more preferably 15 nm or less, or 10 nm or less.

[0248] The method for forming the fluorine-containing organosilicon compound layer includes the following methods: perfluoroalkyl group; -Fluoroalkyl, such as fluoroalkyl groups containing fluoro(polyoxyalkylene) chains A composition of a silane coupling agent having a group is applied to the surface of the inorganic layer by spin coating or dip coating. Coating method, cast method, slit coating method, spray coating method, etc., and then processing A method of heat treating, in which a fluorine-containing organosilicon compound is vapor-deposited on the surface of an inorganic layer and then heated A highly adhesive fluorine-containing organosilicon compound layer can be obtained by vacuum deposition. In order to achieve this, it is preferable to form the antifouling layer by a vacuum deposition method. The formation of the organic silicon compound layer is carried out by using a coating material containing a fluorine-containing hydrolyzable silicon compound. It is preferable to carry out the process using a composition.

[0249] The composition for forming a coating film is a composition containing a fluorine-containing hydrolyzable silicon compound, There are no particular limitations on the composition as long as it is a composition that can be used to form a film by vacuum deposition. The product may contain any component other than the fluorine-containing hydrolyzable silicon compound. The composition may be composed of only a water-decomposable silicon compound. Optional components include those that do not impair the effects of the present invention. Hydrolyzable silicon compounds that do not contain fluorine atoms (hereinafter referred to as "non-fluorine compounds") are used within a range that does not cause Hydrolyzable silicon compounds), catalysts, etc.

[0250] The fluorine-containing hydrolyzable silicon compound used in forming the fluorine-containing organosilicon compound coating is The resulting fluorine-containing organosilicon compound coating has antifouling properties such as water repellency and oil repellency. If any, there is no particular limitation.

[0251] The fluorine-containing hydrolyzable silicon compound is specifically a perfluoropolyether group, One or more selected from the group consisting of fluoroalkylene groups and perfluoroalkyl groups. These groups are hydrolyzable fluorine-containing silicon compounds having the following groups: It exists as a fluorine-containing organic group bonded directly or via a linking group to the silicon atom of the silyl group. The perfluoropolyether group is a group consisting of a perfluoroalkylene group and an ether acid. It refers to a divalent group having a structure in which atomic atoms are bonded alternately.

[0252] Commercially available perfluoropolyether, perfluoroalkylene and perfluoroalkylene derivatives Fluorine-containing organosilicon compounds having one or more groups selected from the group consisting of fluoroalkyl groups. The compounds are KP-801, X-71, KY-130, KY-178, KY-185( Both are manufactured by Shin-Etsu Chemical Co., Ltd., and Optool (registered trademark) DSX (Daikin Industries, Ltd. Among these, KY-185, Optool (registered trademark) D SX is preferred.

[0253] In addition, when commercially available fluorine-containing hydrolyzable silicon compounds are supplied together with a solvent, It is preferred that commercially available fluorine-containing hydrolyzable silicon compounds be used after removing the solvent. The film-forming composition includes a fluorine-containing hydrolyzable silicon compound and, if necessary, The composition is prepared by mixing the composition with any optional components, and is then subjected to vacuum deposition.

[0254] A coating composition containing such a fluorine-containing hydrolyzable silicon compound is applied to the surface of the inorganic layer. By depositing the compound on a surface and allowing it to react to form a film, a fluorine-containing organosilicon compound layer can be obtained. In this case, the antifouling layer is formed from a cured product of a coating composition containing a fluorine-containing hydrolyzable silicon compound. In addition, the specific vacuum deposition method and reaction conditions are appropriately selected from the conventionally known methods and conditions. It is possible to use.

[0255] <<Other optical films>> The optical film 80 shown in FIG. 9 includes a functional layer 85, but the optical film 80 shown in FIG. The surface 90 of the optical film 90 does not have to have a functional layer. A is composed of the surface 82A of the resin layer 82.

[0256] <<<Image display devices>>> The optical films 80 and 90 can be incorporated into a foldable image display device. The structure of the image display device incorporating the optical films 80 and 90 is The structure is the same as that of the image display device 60, except that the optical film 80 and 90 are used instead of the optical film 30. .

[0257] According to this embodiment, since the resin layer 82 contains the organic particles 83B, Not only the surface 82A but also the surface 80A of the optical film 80 can be made uneven. This allows the transmitted and reflected light to be blurred, so pressing a finger on the surface creates a temporary dent. Even if pressure does occur, the pressure marks are not easily noticeable.

[0258] According to this embodiment, the organic particles 83B in the resin layer 82 are spaced apart from the center line CL by the resin substrate 81. Since the organic particles 83B are unevenly distributed on the side of the bend S3, pressure is not applied to the organic particles 83B near the bend S3 during folding. In particular, if organic particles are present on the surface side of the resin layer, When the optical film is folded so that the surface of the resin layer is on the outside (i.e., outward bending), However, in this embodiment, the organic particles 83B in the resin layer 82 Since the resin layer 82 is unevenly distributed on the resin base material 81 side from the center line CL, the surface 82A of the resin layer 82 faces outward. Therefore, even when the optical film 80 is folded, cracks can be suppressed. Such an optical film 80 is formed so that the surface 82A of the resin layer 82 faces outward. This is particularly effective when folding the frame 80.

[0259] According to this embodiment, the organic particles 83B in the resin layer 82 are spaced apart from the center line CL by the resin substrate 81. Since the organic particles 83B are unevenly distributed on the surface 82A side of the resin layer 82, no organic particles 83B are present near the surface 82A of the resin layer 82. This makes it possible to improve the surface hardness and scratch resistance. EXAMPLES

[0260] In order to explain the present invention in detail, the following examples are given. Not limited to the description.

[0261] <Preparation of composition for hard coat layer> First, the components were mixed to obtain the composition shown below to obtain a composition for a hard coat layer. . (Hardcoat layer composition 1) Dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate Mixture of cellulose acetate (product name "M403", manufactured by Toa Gosei Co., Ltd.): 25 parts by weight Dipentaerythritol EO modified hexaacrylate (product name: A-DPH-6E, Shin-Nakamura Chemical Co., Ltd.): 25 parts by weight - Irregularly shaped silica particles (average particle size 25 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.): 50 parts by mass (solid (100% conversion value) Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Omnirad 184'', manufactured by IGM Resins BV): 4 parts by mass Fluorine-based leveling agent (product name "F568", manufactured by DIC Corporation): 0.2 parts by mass (solid (100% conversion value) Methyl isobutyl ketone (MIBK): 150 parts by weight

[0262] (Hardcoat layer composition 2) Multifunctional acrylate (product name: KAYARAD PET-30, manufactured by Nippon Kayaku Co., Ltd.) ):18 parts by mass EO modified acrylate (product name "ATM-35E", manufactured by Shin-Nakamura Chemical Co., Ltd.): 1 2 parts by mass Inorganic particles (fumed silica, octylsilane treatment, average particle size 12 nm, Nippon Aeroge Manufactured by TEL Corporation): 0.6 parts by weight Organic particles (particle size 2 μm, refractive index 1.555, spherical acrylic-styrene copolymer): 1 .5 parts by mass Silicone leveling agent: 0.075 parts by weight Polymerization initiator (product name "Omnirad184", manufactured by IGM Resins BV) :0.3 parts by mass Toluene: 50 parts by weight Propylene glycol monomethyl ether acetate: 17 parts by weight Cyclohexanone: 1 part by weight Isopropanol: 2 parts by weight

[0263] (Hardcoat layer composition 3) EO modified acrylate (product name "A-DPH18E", manufactured by Shin-Nakamura Chemical Co., Ltd.): 15 parts by mass Reactive acrylic polymer (product name "SMP220A", solid content 50%, dilution solvent methyl Isobutyl ketone, manufactured by Kyoeisha Chemical Co., Ltd.: 10 parts by mass Inorganic particles (organosilica sol, product name "MIBK-SD", SiO2 solid content 30%, Dilution solvent: methyl isobutyl ketone, particle size 10-15 nm, manufactured by Nissan Chemical Industries, Ltd.) 5 0 parts by mass Silicone leveling agent: 0.15 parts by weight Polymerization initiator (product name "Omnirad184", manufactured by IGM Resins BV) :1 part by mass Propylene glycol monomethyl ether: 24 parts by weight

[0264] (Hardcoat layer composition 4) Multifunctional acrylate (product name: KAYARAD PET-30, manufactured by Nippon Kayaku Co., Ltd.) ):18 parts by mass EO modified acrylate (product name "ATM-35E", manufactured by Shin-Nakamura Chemical Co., Ltd.): 1 2 parts by mass Organic particles (particle size 3.5 μm, refractive index 1.540, spherical acrylic-styrene copolymer) :2.5 parts by mass Organic particles (particle size 3.5 μm, refractive index 1.555, spherical acrylic-styrene copolymer) :0.4 parts by mass Silicone leveling agent: 0.075 parts by weight Polymerization initiator (product name "Omnirad184", manufactured by IGM Resins BV) :0.3 parts by mass Toluene: 50 parts by weight Propylene glycol monomethyl ether acetate: 18 parts by weight Cyclohexanone: 1 part by weight Isopropanol: 2 parts by weight

[0265] (Hardcoat layer composition 5) Multifunctional acrylate (product name: KAYARAD PET-30, manufactured by Nippon Kayaku Co., Ltd.) ):19 parts by mass EO modified acrylate (product name "ATM35E", manufactured by Shin-Nakamura Chemical Co., Ltd.): 16 Mass part Silicone leveling agent: 0.15 parts by weight Polymerization initiator (product name "Omnirad184", manufactured by IGM Resins BV) :1 part by mass Propylene glycol monomethyl ether: 64 parts by weight

[0266] <Composition for resin layer> The components were mixed so as to obtain the composition shown below, thereby obtaining a composition for a resin layer. (Composition 1 for resin layer) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name: Viscoat #200, Osaka Organic Chemical Industry Ltd.) ): 20 parts by mass Polymerization initiator (product name "Ominirad127", manufactured by IGM Resins BV) ):3 parts by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0267] (Composition 2 for resin layer) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name: Viscoat #150D, Osaka Organic Chemical Industry Co., Ltd.) ): 10 parts by mass Monofunctional acrylic monomer (product name: Viscoat #200, Osaka Organic Chemical Industry Ltd.) ): 10 parts by mass Polymerization initiator (product name "Ominirad127", manufactured by IGM Resins BV) ):3 parts by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0268] (Composition 3 for resin layer) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name: Viscoat #150D, Osaka Organic Chemical Industry Co., Ltd.) ): 20 parts by mass Polymerization initiator (product name "Ominirad127", manufactured by IGM Resins BV) ):3 parts by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0269] (Composition 4 for resin layer) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name: Viscoat #150D, Osaka Organic Chemical Industry Co., Ltd.) ): 20 parts by mass Polymerization initiator (product name "Ominirad127", manufactured by IGM Resins BV) ):1 part by mass Polymerization initiator (product name "Ominirad184", manufactured by IGM Resins BV) ):2 parts by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0270] (Composition 5 for resin layer) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name: Viscoat #150D, Osaka Organic Chemical Industry Co., Ltd.) ): 20 parts by mass Polymerization initiator (product name "Ominirad127", manufactured by IGM Resins BV) ):6 parts by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0271] (Composition for resin layer 6) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name "ACMO", manufactured by KJ Chemicals Co., Ltd.): 20 Quantity Polymerization initiator (product name "Ominirad127", manufactured by IGM Resins BV) ):3 parts by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0272] (Composition 7 for resin layer) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name "IBXA", manufactured by Osaka Organic Chemical Industry Ltd.): 20 Mass part Polymerization initiator (product name "Ominirad127", manufactured by IGM Resins BV) ):3 parts by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0273] (Composition 8 for resin layer) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name: Viscoat #150D, Osaka Organic Chemical Industry Co., Ltd.) ): 10 parts by mass Monofunctional acrylic monomer (product name: Viscoat #200, Osaka Organic Chemical Industry Ltd.) ): 5 parts by mass Monofunctional acrylic monomer (product name "ACMO", manufactured by KJ Chemicals Co., Ltd.): 5 mass Department Polymerization initiator (product name "Ominirad127", manufactured by IGM Resins BV) ):5 parts by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0274] (Composition 9 for resin layer) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name: Viscoat #150D, Osaka Organic Chemical Industry Co., Ltd.) ): 20 parts by mass Polymerization initiator (product name: OminiradTPOH, IGM Resins BV) ): 3 parts by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0275] (Composition 10 for resin layer) Urethane acrylate (product name "UV3310B", manufactured by Mitsubishi Chemical Corporation): 80 Mass part Monofunctional acrylic monomer (product name: Viscoat #150D, Osaka Organic Chemical Industry Co., Ltd.) ): 20 parts by mass Polymerization initiator (product name "Ominirad127", manufactured by IGM Resins BV) ):2 parts by mass Polymerization initiator (product name "Ominirad184", manufactured by IGM Resins BV) ):2 parts by mass Polymerization initiator (product name: OminiradTPOH, IGM Resins BV) ): 1 part by mass Methyl isobutyl ketone (MIBK): 10 parts by weight

[0276] (Composition 11 for resin layer) Urethane acrylate (product name "UV-3310B", manufactured by Mitsubishi Chemical Corporation): 9 0 parts by mass Phenoxyethyl acrylate (product name: Viscoat #192, Osaka Organic Chemical Industry Co., Ltd.) Company: 10 parts by weight Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Omnirad 184'', manufactured by IGM Resins BV): 5 parts by mass Methyl isobutyl ketone: 10 parts by weight

[0277] (Composition 12 for resin layer) Urethane acrylate (product name "UV-3310B", manufactured by Mitsubishi Chemical Corporation): 5 0 parts by mass Ethoxylated pentaerythritol tetraacrylate (product name "ATM-35E", new Nakamura Chemical Co., Ltd.: 40 parts by weight Dicyclopentanyl acrylate (product name "FA-513AS", manufactured by Hitachi Chemical Co., Ltd.) ):10 parts by mass Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Omnirad 184'', manufactured by IGM Resins BV): 5 parts by mass Methyl isobutyl ketone: 10 parts by weight

[0278] (Composition 13 for resin layer) Urethane acrylate (product name "UV-3310B", manufactured by Mitsubishi Chemical Corporation): 8 0 parts by mass Ethoxylated pentaerythritol tetraacrylate (product name "ATM-35E", new Nakamura Chemical Co., Ltd.: 10 parts by weight Phenoxyethyl acrylate (product name: Viscoat #192, Osaka Organic Chemical Industry Co., Ltd.) Company: 10 parts by weight Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Omnirad 184'', manufactured by IGM Resins BV): 5 parts by mass Methyl isobutyl ketone: 10 parts by weight

[0279] (Composition 14 for resin layer) Urethane acrylate (product name "UV-3310B", manufactured by Mitsubishi Chemical Corporation): 8 0 parts by mass Pentaerythritol triacrylate and pentaerythritol tetraacrylate Mixture of PET (product name "KAYARAD PET-30", manufactured by Nippon Kayaku Co., Ltd.): 10 Quantity Phenoxyethyl acrylate (product name: Viscoat #150, Osaka Organic Chemical Industry Co., Ltd.) Company: 10 parts by weight Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Omnirad 184'', manufactured by IGM Resins BV): 5 parts by mass Methyl isobutyl ketone: 10 parts by weight

[0280] (Resin layer composition 15) Urethane acrylate (product name "UV-3310B", manufactured by Mitsubishi Chemical Corporation): 5 0 parts by mass Ethoxylated pentaerythritol tetraacrylate (product name "ATM-35E", new Nakamura Chemical Co., Ltd.: 40 parts by weight Acryloylmorpholine (product name "ACMO", manufactured by KJ Chemicals Co., Ltd.): 10 Quantity Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Omnirad 184'', manufactured by IGM Resins BV): 5 parts by mass Methyl isobutyl ketone: 10 parts by weight

[0281] <Preparation of polyimide substrate composition> First, put 8960g of dehydrated dimethylacetamide and and 1,3-bis(3-aminopropyl)tetramethyldisiloxane (AprTMOS) A solution containing 16.0g (0.07mol) of water was added to a controlled temperature of 30℃. ,4'-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA) 14.6g (0.03mol) was gradually added so that the temperature rise was 2°C or less, and the mechanical start The mixture was stirred in a evaporator for 30 minutes. 2,2'-bis(trifluoromethyl)benzidine ( After confirming that it was completely dissolved, '-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA) 565g (1. 27 mol) was gradually added in several portions so that the temperature rise was kept below 2°C, and polyimide A polyimide precursor solution 1 (solid content: 10% by mass) in which precursor 1 was dissolved was synthesized.

[0282] <<Example A and Comparative Example A>> <Example A1> The release film is a 50 μm thick polyethylene terephthalate substrate (product name: COS Moshine (registered trademark A4100, manufactured by Toyobo Co., Ltd.) was prepared and a polyethylene The resin layer composition 1 is applied to the untreated surface of the phthalate substrate with a bar coater to form a coating film. The coating film was then heated at 70°C for 1 minute to remove the soluble substances in the coating film. The agent was evaporated and the ultraviolet irradiation device (Fusion UV Systems Japan, light source H Bal) was used. Using a UV light source, the cumulative amount of ultraviolet light was 100 mJ / cm2 in air from the coating side. 2 To be The coating is then semi-cured by irradiating it with light, and the resulting coating is made of urethane resin with a thickness of 50 μm. A resin layer was formed.

[0283] Next, the composition 1 for hard coat layer was applied to the surface of the resin layer with a bar coater to form a coating film. The coating was then heated at 70°C for 1 minute to remove the The solvent was evaporated, and the sample was then placed in an ultraviolet ray irradiation device (Fusion UV Systems Japan, light source H-Ba Using a UV light source, the UV light was applied from the coating side under conditions of an oxygen concentration of 200 ppm or less. is 300mJ / cm 2 The coating was fully cured by irradiating it until it reached a temperature of 100°C. Thus, a hard coat layer having a thickness of 5 μm was formed.

[0284] Thereafter, the resin layer is peeled off from the polyethylene terephthalate substrate, thereby forming a urethane Thus, an optical film composed of a resin layer made of the resin-based resin and a hard coat layer was obtained.

[0285] The thickness of each layer was measured using a scanning transmission electron microscope (STEM) (product name: S-4800, manufactured by The cross section of the optical film was photographed using a microscope (Hitachi High-Technologies Corporation), and the cross-sectional image was The thickness of each layer was measured at 10 points, and the arithmetic average value of the thicknesses at the 10 points was used. The cross-sectional photographs of the film were taken as follows. First, a 1 mm × 10 mm piece was cut out. A block was prepared by embedding the optical film in an embedding resin, and a general The section preparation method is used to cut uniform sections with a thickness of 70 nm to 100 nm without holes. Sections were prepared using an ultramicrotome (Leica Microsystems, Inc.). EM UC7 was used. The uniform section without holes was used as the measurement sample. Then, a cross-sectional photograph of the measurement sample was taken using a scanning transmission electron microscope (STEM). When taking a cross-sectional photograph of the resin layer, the detector was set to "SE", the acceleration voltage to "5 kV", and the emitter The SEM observation was performed with the current set to 10 μA. The magnification was adjusted by adjusting the focus. Observe the contrast and brightness of each layer at 1,000x to 10,000x magnification to see if they can be distinguished. When taking a cross-sectional photograph of the hard coat layer, the detector was set to "TE" and the accelerating STEM observation was performed with a voltage of 30 kV and an emission current of 10 μA. Adjust the focus and observe the contrast and brightness to see if each layer can be distinguished. The magnification was adjusted appropriately from 5,000 to 200,000. In addition, set the beam monitor aperture to "3" and the objective lens aperture to "3". In Examples A2 to A15 and Comparative Examples A1 and A2, The thickness of each layer was measured in the same manner as in Example A1.

[0286] <Example A2> In Example A2, the resin layer composition 2 was used instead of the resin layer composition 1. Other than that, an optical film was obtained in the same manner as in Example A1.

[0287] <Example A3> In Example A3, the resin layer composition 3 was used instead of the resin layer composition 1. Other than that, an optical film was obtained in the same manner as in Example A1.

[0288] <Example A4> In Example A4, Resin layer composition 4 was used instead of Resin layer composition 1. Other than that, an optical film was obtained in the same manner as in Example A1.

[0289] <Example A5> In Example A5, the resin layer composition 5 was used instead of the resin layer composition 1. Other than that, an optical film was obtained in the same manner as in Example A1.

[0290] <Example A6> In Example A6, the resin layer composition 6 was used instead of the resin layer composition 1. Other than that, an optical film was obtained in the same manner as in Example A1.

[0291] <Example A7> In Example A7, Resin layer composition 7 was used instead of Resin layer composition 1. Other than that, an optical film was obtained in the same manner as in Example A1.

[0292] <Example A8> In Example A8, the same procedure as in Example A3 was followed except that the thickness of the resin layer was 40 μm. Thus, an optical film was obtained.

[0293] <Example A9> In Example A9, the same procedure as in Example A3 was followed except that the thickness of the resin layer was 25 μm. Thus, an optical film was obtained.

[0294] <Example A10> In Example A10, the resin layer composition 8 was used instead of the resin layer composition 1. An optical film was obtained in the same manner as in Example A1, except that the thickness of the fat layer was 70 μm. .

[0295] <Example A11> In Example A11, the thickness of the resin layer was 80 μm, but the same as in Example A10. Similarly, an optical film was obtained.

[0296] <Example A12> In Example A12, the same procedure as in Example A10 was followed except that the thickness of the resin layer was 90 μm. Similarly, an optical film was obtained.

[0297] <Example A13> In Example A13, the thickness of the resin layer was 100 μm, but the same procedure as in Example A10 was repeated. In the same manner as above, an optical film was obtained.

[0298] <Example A14> In Example A14, the thickness of the resin layer was 115 μm, but the same as in Example A10. In the same manner as above, an optical film was obtained.

[0299] <Example A15> In Example A15, the thickness of the resin layer was 140 μm, but the same as in Example A10. In the same manner as above, an optical film was obtained.

[0300] <Comparative Example A1> In Comparative Example A1, the resin layer composition 9 was used instead of the resin layer composition 1, and When forming the resin layer, the accumulated light intensity of ultraviolet rays in the air from the coating side is 500 mJ / cm 2 Nina An optical film was obtained in the same manner as in Example A1, except that irradiation was performed so as to obtain an optical film.

[0301] <Comparative example A2> In Comparative Example A2, the resin layer composition 10 was used instead of the resin layer composition 1. When forming the hard coat layer, ultraviolet light is additionally irradiated from the release film side in the air. Amount is 300mJ / cm 2 The same procedure as in Example A1 was repeated except that the irradiation was performed so that I got a film of the school.

[0302] <Displacement measurement> The first region of the resin layer of the optical film according to Examples A1 to A15 and Comparative Examples A1 and A2 A Berkovich indenter is pressed into the third region with a constant load to perform an indentation test. d1 to d3 were measured. Specifically, first, the optical The film was embedded in resin to create a block, from which standard sections were then cut. Depending on the manufacturing method, a uniform section with a thickness of 70 nm to 100 nm is cut out without holes. Sections were prepared using an ultramicrotome (Leica Microsystems, Inc.). UC7 was used. The remaining block from which the uniform slices without holes were cut was Next, in the measurement sample, the resin layer was Divide the oil layer into three equal parts, and apply pressure from the first side (the side of the hard coat layer of the resin layer) to the second side (the side opposite to the first side). The first region, the second region, and the third region were then respectively measured. The cross section obtained by cutting out the slice is measured using a nanoindenter. (Bruker TI950 TriboIndenter) The measurement conditions are as follows: The awl (Bruker TI-0039) was placed in the center of the cross section of the first region of the resin layer for 40 seconds. The specimen was pressed vertically with a maximum load of 200 μN, and the displacement (pressure depth) d1 was measured. Here, the Berkovich indenter is positioned in the first region so as to avoid the influence of the side edge of the resin layer. The resin layer was pressed into the center of the resin layer at a distance of 500 nm or more from each of the two ends of the resin layer. The displacement d1 was the arithmetic average of the values ​​measured at three locations. If any measurement values ​​deviate from the average by more than ±20%, they are excluded and remeasured. The measurement values ​​were determined to be greater than ±20% off the arithmetic mean. The determination was made by the formula explained in the embodiment. In addition, the displacement amount d2 of the second region of the resin layer The displacement amount d3 of the third region was also measured in the same manner as the displacement amount d1 of the first region. (Measurement conditions) Control method: Load control (maximum load 200μN) Lift amount: 0nm Preload: 0.5μN ·Loading speed: 5μN / sec Maximum load hold time: 5 seconds ·Unloading speed: 5μN / sec ·Temperature: 23℃ Relative humidity: 50%

[0303] <Foldability> The optical films according to Examples A1 to A15 and Comparative Examples A1 and A2 were continuously folded. The test was conducted to evaluate the folding property. Specifically, first, a 30 mm x 1 A sample with a size of 0.00 mm was cut out. The two opposing sides of the cut sample were , and a folding durability tester (product name "U-shaped stretch tester DLDMLH-FS") arranged in parallel , manufactured by Yuasa System Co., Ltd., compliant with IEC62715-6-1) Then, as shown in FIG. 4(C), the minimum distance φ between the two opposing sides was set to 10 mm, and the surface side of the optical film (the hard coat layer side) is on the outside. A folding test was conducted in which the product was folded 180° 100,000 times under the conditions described above, and no deformation, cracks or breaks were observed in the bent parts. The continuous folding test was carried out in an environment with a temperature of 23°C and a relative humidity of 50%. The evaluation criteria were as follows. Regarding foldability, there were no cracks or cracks in the bent parts. As long as no breakage occurred, the product was deemed to be in good condition. A: During the continuous folding test, no deformation, cracks or breaks occurred in the bent parts. B: In the continuous folding test, deformation was confirmed at the bend that was not a problem for practical use. No cracks or breaks occurred. C: In the continuous folding test, deformation was clearly observed at the bent part, but cracks or breaks were not observed. It hadn't happened. D: During the continuous folding test, cracks or breaks occurred at the bent portion.

[0304] <Impact resistance> Impact resistance tests were performed using the optical films according to Examples A1 to A15 and Comparative Examples A1 and A2. Specifically, a hard coat layer was applied to the surface of a 0.7 mm thick soda glass. The optical films according to Examples A1 to A15 and Comparative Examples A1 and A2 were directly placed on the upper side. An iron ball weighing 100g and having a diameter of 30mm was dropped from a height of 30cm onto the hard surface of the optical film. The impact resistance test was carried out by dropping the sample on the surface of the coated layer three times. The position where the iron ball was dropped was changed each time. In the film, the surface of the hard coat layer is visually indented or the soda glass is The evaluation results were as follows. Either the surface dent evaluation of the hard coat layer or the crack evaluation of the soda glass is not "D" As far as this goes, it is considered to be good. (Evaluation of dents on the surface of the hard coat layer) A: When the hard coat layer is observed from the front and from an oblique angle, No depressions were observed on the surface of the layer. B: When the hard coat layer is observed from the front or obliquely, Although depressions were observed on the surface of the coating layer, they were at a level that would not cause any practical problems. C: When the hard coat layer is observed from the front, a dent is observed on the surface of the hard coat layer. However, when observed obliquely, depressions were observed on the surface of the hard coat layer. D: When the hard coat layer is observed from the front and obliquely, the hard coat Obvious pitting was observed on the surface of the layer. (Soda glass cracking evaluation) A: The soda glass did not break or get scratched. B: The soda glass was scratched but did not break. C: The soda glass cracked once. D: The soda glass cracked two or three times.

[0305] <Pencil hardness> The surfaces of the optical films according to Examples A1 to A15 and Comparative Examples A1 and A2 (hard coat The pencil hardness at the surface of the layer was measured based on JIS K5600-5-4:1999. Specifically, first, an optical fiber cut to a size of 30 mm x 100 mm was The film is placed on a 2mm thick glass plate measuring 50mm x 100mm, with care to avoid any creases or bends. The specimen was fixed with Cellotape (registered trademark) manufactured by Nichiban Co., Ltd. Then, the specimen was subjected to a pencil hardness test using a pencil hardness tester (manufactured by Using a pencil scratch coating hardness tester (electric type) manufactured by Toyo Seiki Seisakusho Co., Ltd. The test was performed using a pencil (product name "Uni", Mitsubishi Pencil Co., Ltd.) at a temperature of 23°C and a relative humidity of 50%. A 750g load was applied to the pencil (manufactured by the company) while the pencil was moved at a speed of 1mm / sec. The pencil hardness was In the pencil hardness test, the surface of the optical film (the surface of the hard coat layer) was not scratched. The hardness was determined as the highest hardness. When measuring the pencil hardness, multiple pencils with different hardness were used. The pencil hardness test is carried out 5 times for each pencil, and optical hardness is measured under fluorescent light for at least 4 times out of the 5 times. If no scratches are visible on the surface of the optical film when observing the surface of the film through a transmission It was determined that the pencil of this hardness did not scratch the surface of the optical film.

[0306] The results are shown in Table 1 below. [Table 1]

[0307] The results are described below. In the optical film according to Comparative Example A1, the displacement amount d1 was d 2 and did not satisfy the above relational formula (1), so the folding ability was poor. In addition, in the optical film according to Comparative Example A2, the displacement amount d2 is larger than the displacement amount d3, and Since the relational expression (1) was not satisfied, the folding property was poor. The optical films according to A1 to A15 satisfied the above relational formula (1), and therefore had excellent foldability. And the impact resistance was good.

[0308] <<Example B and Comparative Example B>> <Example B1> The polyimide precursor solution 1 obtained above was used to prepare a single layer of polyimide having a thickness of 12 μm according to the following procedure. First, polyimide precursor solution 1 was applied onto a glass plate, and 1 The coating was formed by drying for 10 minutes in a circulating oven at 20°C. The lath plate was heated to 350℃ at a rate of 10℃ / min under a nitrogen gas flow (oxygen concentration 100ppm or less). The temperature was raised to 350°C, and then the temperature was kept at 350°C for 1 hour, after which the temperature was cooled to room temperature. A single-layer polyimide substrate was obtained.

[0309] Next, a hard coat layer composition was applied to the surface (second surface) of the polyimide substrate using a bar coater. 1 was applied to form a coating film. The coating film was then heated at 70°C for 1 minute. This evaporates the solvent in the coating, and the ultraviolet irradiation device (Fusion UV Systems Japan) The UV light was emitted in air with an integrated dose of 200 mJ / cm using a light source H bulb manufactured by Pan. 2 The coating was cured by irradiating the film so that a thickness of 5 μm was formed on the polyimide substrate. A hard coat layer of the above composition was formed.

[0310] After forming a hard coat layer on the polyimide substrate, the glass plate is peeled off from the polyimide substrate. Then, the resin layer composition 11 was applied to the first surface of the polyimide substrate opposite to the second surface with a bar coater. The coating was then heated at 70°C for 1 minute. The solvent in the coating is evaporated by this, and the ultraviolet irradiation equipment (Fusion UV Systems Japan) The ultraviolet light was emitted in air with an integrated light intensity of 1200 mJ / cm2 using a light source (H bulb manufactured by Epson Corporation). 2 The coating is hardened by irradiating it so that the thickness of the coating is 80 μm. A layer was formed. As a result, an optical film was obtained.

[0311] The thickness of the polyimide substrate was measured by cross-sectional observation of the polyimide substrate using a scanning electron microscope (SEM). The thickness of the polyimide substrate was measured at 20 points on the cross-sectional image. The arithmetic average value of the thickness of each section was used. The cross-sectional photograph was taken according to the hardware method described in Example A. The method for taking cross-sectional photographs was the same as that for measuring the thickness of the coating layer. The thickness of the coating layer was measured in the same manner as the thickness of the polyimide substrate. In the comparative examples B1 to B7 and B4, polyimide was produced by the same method as in the example B1. The thickness of the substrate, the thickness of the resin layer, and the thickness of the hard coat layer were measured.

[0312] <Example B2> In Example B2, the thickness of the polyimide substrate was 8 μm, but the same procedure as in Example B1 was repeated. In the same manner as above, an optical film was obtained.

[0313] <Example B3> In Example B3, the thickness of the polyimide substrate was 18 μm, but the same as in Example B An optical film was obtained in the same manner as in 1.

[0314] <Example B4> In Example B4, the same procedure as in Example B1 was followed except that the thickness of the resin layer was 60 μm. Thus, an optical film was obtained.

[0315] <Example B5> In Example B5, the same procedure as in Example B1 was followed except that the thickness of the resin layer was 100 μm. In this manner, an optical film was obtained.

[0316] <Example B6> In Example B6, the resin layer composition 12 was used instead of the resin layer composition 11. Except for the above, an optical film was obtained in the same manner as in Example B1.

[0317] <Example B7> In Example B7, Resin layer composition 13 was used instead of Resin layer composition 11. Except for the above, an optical film was obtained in the same manner as in Example B1.

[0318] <Comparative Example B1> In Comparative Example B1, the thickness of the polyimide substrate was 30 μm, but the same as in Example B An optical film was obtained in the same manner as in 1.

[0319] <Comparative example B2> In Comparative Example B2, the thickness of the resin layer was 30 μm, but the same as in Example B1. Thus, an optical film was obtained.

[0320] <Comparative Example B3> In Comparative Example B3, Resin layer composition 14 was used instead of Resin layer composition 11. Except for the above, an optical film was obtained in the same manner as in Example B1.

[0321] <Comparative example B4> In Comparative Example B4, Resin layer composition 15 was used instead of Resin layer composition 11. Except for the above, an optical film was obtained in the same manner as in Example B1.

[0322] <Displacement measurement> The polyimide substrates of the optical films according to Examples B1 to B7 and Comparative Examples B1 to B4 A Berkovich indenter was pressed into the cross section of the resin layer with a maximum load of 200 μN. The displacement amount d4 of the polyimide base material and the displacement amount d5 of the resin layer were measured. The displacement d4 was measured in the same manner as the displacements d1 to d3 described in the column of Example A. The measurement was performed by the Berkovich indenter, but the indenter was used at 100° to avoid the influence of the side edge of the polyimide substrate. In order to prevent this, the polyimide substrate was placed 500 nm from each side of the polyimide substrate toward the center. The displacement d4 is the arithmetic mean value of the values ​​measured at three points. If any of the measured values ​​deviates from the arithmetic mean by ±20% or more, If any of the measurements were within ±20% of the arithmetic mean value, the measurement was excluded and remeasured. Whether or not there is anything that is above the upper limit is determined by the formula explained in the embodiment. The displacement amount d5 of the resin layer was measured in the same manner as the displacement amount d4 of the polyimide substrate.

[0323] <Foldability> A continuous folding test was performed on the optical films according to Examples B1 to B7 and Comparative Examples B1 to B4. The continuous folding test was carried out to evaluate the folding property. The folding test was carried out in the same manner as the folding test. The evaluation criteria were the same as those in the continuous folding test described in the Example A column. The evaluation criteria were the same as those for the folding test.

[0324] <Folding Habit Evaluation> In the optical films according to Examples B1 to B7 and Comparative Examples B1 to B4, the films were folded and left to stand. The test was carried out to evaluate whether or not the folding crease was observed. The optical film was cut into a size of 0.1 mm. The area of ​​30mm x 48mm including the two opposing short sides (30mm) is divided into 50mm The glass plates were fixed to the optical film resin. The optical film was then fixed to the side of the layer so that the distance between the opposing sides was 2.5 mm. A glass plate is placed parallel to the optical film, and the optical film is folded so that the hard coat layer is on the inside. In this state, the product is left for 100 hours at a temperature of 25°C and a relative humidity of 50% for a folding static test. After that, the optical film was opened with the glass plate still attached, and the surface of the optical film was flattened. Then, it was confirmed whether the surface of the optical film had any creases. The evaluation criteria were as follows: The following is the procedure. A: When the optical film is observed from the front and from an oblique angle, No creases were observed. B: When the optical film is observed from the front or obliquely, Although some folding tendencies were observed in the paper, this was not at a level that would cause any practical problems. C: When the optical film was observed from the front, no creases were observed in the optical film. However, when observed obliquely, a fold was observed in the optical film. D: When the optical film is observed from the front and from an oblique angle, Obvious folding was observed.

[0325] <Impact resistance evaluation> Impact resistance test was performed using the optical films according to Examples B1 to B7 and Comparative Examples B1 to B4. Specifically, first, the optical film was cut to a size of 50 mm x 50 mm. Then, on the surface of a 0.7mm thick soda glass measuring 50mm x 50mm, The optical film was placed directly on the surface with the hard coat layer facing up, and the A ballpoint pen (orange, manufactured by BIC Japan) weighing 100g and with a 0.7mm tip The pen tip was dropped onto the surface of the hard coat layer of the optical film with the tip facing downwards. The impact resistance test was carried out three times for each. The thickness was changed each time. After the impact resistance test, the optical film was visually inspected for the following: The surface of the hard coat layer was evaluated for depressions by the above method. The evaluation results were as follows. A: When the hard coat layer is observed from the front and from an oblique angle, No depressions were observed on the surface of the layer. B: When the hard coat layer is observed from the front or obliquely, Although depressions were observed on the surface of the coating layer, they were at a level that would not cause any practical problems. C: When the hard coat layer is observed from the front, a dent is observed on the surface of the hard coat layer. However, when observed obliquely, depressions were observed on the surface of the hard coat layer. D: When the hard coat layer is observed from the front and obliquely, the hard coat Obvious pitting was observed on the surface of the layer.

[0326] <Pencil hardness> The surfaces (hard coat layers) of the optical films according to Examples B1 to B7 and Comparative Examples B1 to B4 The pencil hardness on the surface of the The pencil hardness was measured in the same manner as described in Example A. It was done.

[0327] The results are shown in Table 2 below. [Table 2]

[0328] The results are described below. In the optical film according to Comparative Example B1, the polyimide group The thickness of the material was too thick, so a folding tendency was observed after the folding and standing test. In this optical film, the thickness of the resin layer was too thin, and therefore good impact resistance was not obtained. In the optical film according to Comparative Example B3, the displacement amount of the resin layer in the indentation test was Since the size was too small, good folding properties were not obtained. In the case of the CFRP, the displacement of the resin layer during the indentation test was too large, so impact resistance could not be guaranteed. In contrast, in the optical films according to Examples B1 to B7, the polyimide substrate The thickness is 20 μm or less, the thickness of the resin layer is 50 μm or more, and the thickness of the polyimide base material The ratio of the resin layer thickness to the thickness of the resin layer is 4.0 or more and 12.0 or more, and when the indentation test is performed The displacement d4 of the polyimide substrate was 50 nm or more and 250 nm or less, and the indentation test was performed. The displacement d5 of the resin layer at this time was 200 nm or more and 1500 nm or less. When a test was carried out, no creases were observed, and good impact resistance was obtained.

[0329] <<Example C and Comparative Example C>> <Example C1> The resin substrate was a 50 μm thick polyimide substrate (product name: Neoprim (registered trademark) " manufactured by Mitsubishi Gas Chemical Co., Inc.) was prepared. The Neoprim (registered trademark) used in the above is commercially available as a polyimide film. Then, a hard coat layer was applied to one side of the polyimide substrate using a bar coater. The coating composition 2 was applied to the substrate to form a coating film. The coating film was then heated at 70° C. for 1 minute. The solvent in the coating is evaporated by heating, and then the coating is heated with an ultraviolet ray irradiation device (Fusion UV System). Using a light source H bulb manufactured by Thames Japan, the accumulated light intensity of ultraviolet rays in air is 200m J / cm 2 The coating is hardened by irradiating the light so that the first hard coat layer is formed with a thickness of 3 μm. Formed.

[0330] Next, the composition 3 for hard coat layer is applied to the surface of the first hard coat layer with a bar coater. The coating film was then heated at 70°C for 1 minute to form a coating film. The solvent in the film was evaporated, and the film was then exposed to ultraviolet light (Fusion UV Systems Japan, light source). The ultraviolet light was emitted using a UV light source (H bulb) under conditions of oxygen concentration of 200 ppm or less, with an integrated light intensity of 2 00mJ / cm 2 The coating was cured by irradiating the polyimide substrate with light so that the A first hard coat layer having a thickness of 3 μm is formed on the first hard coat layer. A hard coat layer consisting of the first hard coat layer and the second hard coat layer of m was formed to obtain an optical film.

[0331] The thickness of each layer was measured using a scanning transmission electron microscope (STEM) (product name: S-4800, manufactured by The cross section of the optical film was photographed using a microscope (Hitachi High-Technologies Corporation), and the cross-sectional image was The thickness of each layer was measured at 10 points, and the arithmetic average value of the thicknesses at the 10 points was used. The cross-sectional photographs of the film were taken as follows. First, a 1 mm × 10 mm piece was cut out. A block was prepared by embedding the optical film in an embedding resin, and a general The section preparation method is used to cut uniform sections with a thickness of 70 nm to 100 nm without holes. Sections were prepared using an ultramicrotome (Leica Microsystems, Inc.). EM UC7 was used. The uniform section without holes was used as the measurement sample. After that, a cross-sectional photograph of the measurement sample was taken using a scanning transmission electron microscope (STEM). When taking this cross-sectional image, the detector was set to "TE", the acceleration voltage to "30 kV", and the emission The scanning current was set to 10 μA for STEM observation. Observe the contrast and brightness of each layer at 5,000 to 200,000 magnifications. When taking cross-sectional photographs, the beam monitor aperture was set to "3" The objective lens aperture was set to "3", and the WD was set to "8 mm". In Example C1 and Comparative Examples C1 to C3, the thickness of each layer was measured in the same manner as in Example C1. It was determined.

[0332] <Example C2> In Example C2, the thickness of the first hard coat layer was set to 4 μm, and the thickness of the second hard coat layer was set to 1 μm. An optical film was obtained in the same manner as in Example C1, except that the thickness of the layer was 4 μm.

[0333] <Example C3> In Example C3, the composition for hard coat layer was replaced with the composition for hard coat layer 2. An optical film was obtained in the same manner as in Example C1, except that No. 4 was used.

[0334] <Example C4> In Example C4, the composition for hard coat layer was replaced with the composition for hard coat layer 3. An optical film was obtained in the same manner as in Example C1, except that No. 5 was used. <Example C5> In Example C5, the surface of the second hard coat layer of the optical film according to Example C1 was Then, a 100 nm thick SiO x (x=1 to less than 2) Then, a 2 nm thick film of a fluorine-containing organosilicon compound was formed by vacuum deposition. An optical film was obtained in the same manner as in Example C1, except that an antifouling layer was formed.

[0335] <Comparative Example C1> The resin substrate was a 50 μm thick polyimide substrate (product name: Neoprim (registered trademark) ", manufactured by Mitsubishi Gas Chemical Co., Inc.) was prepared and applied to a first surface, which was one surface of the polyimide-based substrate. Then, the hard coat layer composition 2 was applied with a bar coater to form a coating film. The coating film was heated at 70℃ for 1 minute to evaporate the solvent in the coating film, and then exposed to ultraviolet light. Using an irradiation device (manufactured by Fusion UV Systems Japan, light source H bulb), ultraviolet light When the oxygen concentration is 200 ppm or less, the cumulative light intensity is 400 mJ / cm 2 Irradiate so that The coating was cured to form a hard coat layer with a thickness of 6 μm, thereby obtaining an optical film.

[0336] <Comparative Example C2> In Comparative Example C2, the composition for hard coat layer was replaced with the composition for hard coat layer 2. 3 was used, and composition 2 for hard coat layer was used instead of composition 3 for hard coat layer. Except for the above, an optical film was obtained in the same manner as in Example C1. The optical film has a second hard coat layer containing organic particles on a first hard coat layer. It was something like that.

[0337] <Comparative Example C3> The resin substrate was a 50 μm thick polyimide substrate (product name: Neoprim (registered trademark) ", manufactured by Mitsubishi Gas Chemical Co., Inc.) was prepared and applied to a first surface, which was one surface of the polyimide-based substrate. Then, the composition 3 for hard coat layer was applied with a bar coater to form a coating film. The coating film was heated at 70℃ for 1 minute to evaporate the solvent in the coating film, and then exposed to ultraviolet light. Using an irradiation device (manufactured by Fusion UV Systems Japan, light source H bulb), ultraviolet light The cumulative light intensity in air is 200 mJ / cm 2 The coating is hardened by irradiating it until it becomes A hard coat layer having a thickness of 6 μm was formed to obtain an optical film.

[0338] <Evaluation of uneven distribution of organic particles> In the optical films according to Examples C1 to C5 and Comparative Examples C1 and C2, the organic particles are The hard coat layer is formed on the polyimide substrate at a position closer to the center line that divides the hard coat layer into two equal parts in the thickness direction of the hard coat layer. Specifically, we first used a scanning transmission electron microscope (STEM) to investigate whether the (Product name: S-4800, manufactured by Hitachi High-Technologies Corporation) was used to measure the thickness of each layer. The cross section of the hard coat layer was photographed under the same conditions as those for measuring the cross section of 10 points. In each cross-sectional photograph, the film thickness of the hard coat layer was measured. The center line was determined by the cross-sectional images. The center of the organic particles that appeared in each cross-sectional image was also determined. The closest and furthest points of the organic particles to the polyimide substrate in the thickness direction of the hard coat layer. The midpoint of the imaginary line segment connecting the points was determined. The distance between the center of the particle and the center line was measured. At this time, the center of the organic particle was below the center line ( The distance between the center and the center line of the organic particle located on the polyimide substrate side is "-" and the center When the organic particle was located above the center line, the distance between the center of the organic particle and the center line was marked with a "+". The average position of the center is calculated by taking the average of Depending on whether the mark is "+" or "+", it can be judged whether the mark is on the polyimide substrate side of the center line. The evaluation criteria were as follows. The optical film according to Comparative Example C3 was made of an organic Since it did not contain any particles, it was not included in this evaluation. A: The organic particles were unevenly distributed on the polyimide substrate side from the center line. B: The organic particles were not unevenly distributed on the polyimide substrate side from the center line.

[0339] <Foldability> A continuous folding test was performed on the optical films according to Examples C1 to C5 and Comparative Examples C1 to C3. We carried out experiments to evaluate the folding ability. The cut optical film is placed in a durability tester (product name "DLDMLH-FS", Yuasa System The short sides of the optical film were fixed to the fixing parts of a 3D printer (manufactured by MUKI Co., Ltd.) and the 3D printer was placed in the same position as in Figure 4(C). As shown in the figure, the minimum distance between the two opposing sides is 8 mm. The surface side of the film (hard coat layer in Examples C1 to C4 and Comparative Examples C1 to C3) In Example C5, the sheet is folded 180° so that the stain-resistant layer side (in Example C6, the stain-resistant layer side) is on the outside. The test was carried out 100,000 times, and the bending part was checked for cracks or breakage. The evaluation criteria were as follows: It was as stated above. A: During the continuous folding test, no cracks or breaks occurred at the bent parts. B: In the continuous folding test, some cracks were observed at the bent parts, but this did not cause any problems in practical use. It was at a high level. C: During the continuous folding test, cracks or breaks were clearly observed at the bent portions.

[0340] <Haze value measurement> The optical films according to Examples C1 to C5 and Comparative Examples C1 to C3 were subjected to A haze meter (product name: HM-150, Murayama Corporation) was used in an environment of 50% relative humidity. The haze value (total haze) was measured according to JIS K7136:2000 using a colorimeter manufactured by the Color Research Institute. The total light transmittance and haze value were measured on a 50 mm x 100 mm sheet. The optical film is cut to size and placed on a polypropylene sheet without curls, wrinkles, fingerprints, dust, etc. The imide-based substrate was placed on the haze meter so that it faced the light source. The measurement was performed three times, and the arithmetic mean value obtained from the three measurements was calculated.

[0341] <Transmitted image clarity> The optical films according to Examples C1 to C5 and Comparative Examples C1 to C3 were subjected to and relative humidity of 50% or less, using an image clarity measuring instrument (product name "ICM-1T", Suga Test Instruments The clarity of the transmitted image was measured according to JIS K7374:2007 using a 3D scanner manufactured by FUJIFILM Corporation. The above transmitted image clarity was measured using an optical film cut to a size of 50 mm x 100 mm. The sample is "transmitted" through the optical axis rotating stage and sample stage without curls, wrinkles, fingerprints, dust, etc. The polyimide substrate was placed on the light source side of the image clarity measuring instrument set to 1. The comb was measured three times, and the arithmetic mean value obtained from the three measurements was calculated.

[0342] <Evaluation of pressure marks> The optical films according to Examples C1 to C5 and Comparative Examples C1 to C3 were subjected to The appearance was observed under an environment of 50% or less relative humidity and 50% or less. Two clear adhesive layers (product number "8146-4", 3M) are placed between the tape and the tape. The glass and the polyimide substrate side of the optical film were bonded together to create a 5cm x 10cm panel. An evaluation sample was prepared. Then, the sample was placed on a black table with the optical film facing up. A polyethylene terephthalate film measuring 20 mm x 200 mm and 250 μm thick (PET film) (product name "A4300", Toyobo Co., Ltd.) on top of the evaluation sample A cylindrical weight of 300 g and a diameter of 35 mm was placed on the PET film. After that, the weight and the PET film were removed. Then, after 3 seconds, the weight was pressed against the PET film. The marks were observed and the evaluation criteria were as follows: (Indentation evaluation) A: No pressure marks were found. B: A small amount of pressure marks were observed, but the level was not problematic for practical use. C: Pressure marks were clearly observed.

[0343] <Indentation hardness (H IT ) Measurement> Indentations at the bottom and top of the hard coat layer of the optical films according to Examples C1 to C5 Hardness (H IT Specifically, first, the specimen was cut into 1 mm × 10 mm pieces. The optical film was embedded in an embedding resin to prepare a block, and the block was then The slices are uniform and free of holes, with a thickness of 70 nm to 100 nm, using the general sectioning method. Sections were cut out using the Ultramicroscopy system from Leica Microsystems. A rotomy machine, EM UC7, was used. The uniform sections without holes were cut out. The resulting block was used as a measurement sample. In the cross section obtained by cutting out the Using the I950 TriboIndenter, the following measurement conditions were used: Berkovich indenter (triangular pyramid, BRUKER TI-0039) The test piece was pressed vertically onto the lower cross section of the hard coat layer with a maximum pressing load of 50 μN for 10 seconds. Here, the Berkovich indenter indents the hard coat layer from the interface between the polyimide substrate and the hard coat layer. The hard coat layer is 500 nm away from the center of the hard coat layer, and the hard coat layer is 500 nm away from the center of the hard coat layer. The hard coat layer was pushed into the lower part of the hard coat layer, which was 500 nm or more away from the center of the hard coat layer. After holding the load for 10 seconds, the load was removed over 10 seconds. max and the contact projection area A p Using and, P max / A p The indentation hardness (H IT ) was calculated. The contact projection area was measured using a standard sample of fused quartz (5-0098 manufactured by BRUKER). The contact projection area is corrected for the indenter tip curvature using the Liver-Pharr method. Hardness (H IT ) was the arithmetic average value obtained by measuring 10 points. If any of the values ​​deviate from the arithmetic mean by ±20% or more, exclude those measurements. The measurements were to be removed and remeasured. Any measurements that deviated from the arithmetic mean by ±20% or more were The presence or absence of is determined by the following equation: (AB) / B×1 where A is the measured value and B is the arithmetic mean value. The judgment was made based on whether the value (%) obtained by 00 was ±20% or more. The indentation hardness of the upper part of the hard coat layer was also The hardness is measured in the same manner as the hardness of the hard coat layer, except that the Berkovich indenter is inserted into the hard coat layer. In the upper portion, the hard coat layer is 500 nm away from the surface of the hard coat layer toward the center of the hard coat layer, and A portion that is 500 nm or more away from each side edge of the hard coat layer toward the center of the hard coat layer Pushed it in for minutes. (Measurement conditions) Control method: Load control method ·Loading speed: 5μN / sec ·Holding time: 5 seconds ·Loading and unloading speed: 5μN / sec ·Temperature: 23℃ Relative humidity: 50%

[0344] <Scratch resistance> The surfaces of the optical films according to Examples C1 to C5 were subjected to a scratch resistance test and evaluated. Specifically, an optical film cut to a size of 50 mm x 100 mm is placed on a glass plate. To prevent folding or wrinkling, tape the surface of the optical film with Nichiban Co., Ltd.'s Cellophane Tape (registered trademark). With the plate fixed so that it was on the top, use steel wool #0000 (product name "BON STAR" manufactured by Japan Steel Wool Co., Ltd.) was used, and the 2 Apply a load of The sample was rubbed back and forth 10 times at a speed of 60 mm / sec in an environment with a temperature of 23°C and a relative humidity of 50%. After that, apply black vinyl tape (Yamato) to the glass surface opposite the surface to which the optical film was attached. The black vinyl tape (No. 200-38-21) made by the company was attached and the presence or absence of scratches was checked at three wavelengths. The evaluation was performed by visual inspection under a fluorescent lamp, and the evaluation criteria were as follows: A: No injuries were found. B: A few scratches were observed, but were not of a level that would cause any practical problems. C: More scratches than ○ were found. D: Numerous scratches were found.

[0345] The results are shown in Tables 3 and 4 below. [Table 3]

[0346] [Table 4]

[0347] The results are described below. The optical films according to Comparative Examples C1 and C2 were mainly composed of organic particles. Since the polymer was not unevenly distributed on the polyimide substrate side from the wire, the continuous folding property was poor. This is the surface of the hard coat layer at the bent portion of the optical film during the continuous folding test. It is believed that a crack occurred at the interface between the nearby organic particles and the binder resin, causing the crack to break. In addition, the optical film according to Comparative Example C3 did not contain organic particles in the hard coat layer. This is because the surface of the hard coat layer is flat. In contrast, the optical films according to Examples C1 to C5 The organic particles were unevenly distributed on the polyimide substrate side from the center line, which resulted in excellent continuous folding properties. And the pressure marks were not noticeable. [Explanation of symbols]

[0348] 10, 72, 82...Resin layer 30, 50, 70, 80...Optical film 31, 52, 85…Functional layers 51, 71, 81...Resin substrate 60...Image display device 62...Display element 73...Hard coat layer

Claims

1. An optical film having a laminated structure, which is used in an image display device and includes a resin layer having a single-layer structure and a functional layer having optical transparency, the resin layer has a first surface in contact with the functional layer and a second surface opposite to the first surface, The functional layer is a hard coat layer, an optical film in which the resin layer is divided into three equal parts in a thickness direction of the resin layer, the first region, the second region, and the third region being arranged in that order from a first surface of the resin layer toward a second surface opposite the first surface; and when an indentation test is performed in which a Berkovich indenter is pressed with a constant load into each of the first region, the second region, and the third region in a cross section of the resin layer in the thickness direction, the amount of displacement in the first region is d1, the amount of displacement in the second region is d2, and the amount of displacement in the third region is d3, the relationship of d1<d2<d3 is satisfied.

2. 2. The optical film of claim 1, wherein the ratio of d1 to d3 is less than or equal to 0.

85.

3. 3. The optical film according to claim 1, wherein d1 to d3 are each 200 nm or more and 1000 nm or less.

4. 4. The optical film according to claim 1, having a thickness of 20 μm or more and 150 μm or less.

5. The optical film according to claim 1 , further comprising a resin substrate provided on one of the first surface and the second surface of the resin layer.

6. 6. The optical film according to claim 1, wherein the optical film does not crack or break when a test of folding the optical film 180° so that the distance between opposing sides of the optical film is 10 mm is repeated 100,000 times.

7. A display element; The optical film according to claim 1 , which is disposed on a viewer side relative to the display element; An image display device comprising:

8. The image display device according to claim 7 , wherein the display element is an organic light-emitting diode element.

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