Optical films and image display devices

Abstract

To provide an optical film which has excellent impact resistance and is foldable, and an image display device having the same.SOLUTION: A light-transmissive optical film 10 which is used in an image display device and is foldable includes a resin substrate 11, a hard coat layer 12 provided on a first surface 11A side of the resin substrate 11, and a resin layer 13 which is provided on a second surface 11B side opposite to the first surface 11A of the resin substrate 11 and has film thickness of 50 μm or more and 300 μm or less, wherein a shear storage elastic modulus G' at 25°C in a frequency range of 500 Hz or more and 1,000 Hz or less in the optical film 10 exceeds 200 MPa and 1,200 MPa or less, and a shear loss elastic modulus G'' at 25°C in a frequency range of 500 Hz or more and 1,000 Hz or less in the optical film is 3 MPa or more and 150 MPa or less.SELECTED DRAWING: Figure 1

Description

Reference to related applications

[0001] This application is based on the preceding Japanese patent application No. 2017-1447 (Filing date: January 2017) This grants the benefit of priority on the 6th, and the entirety of its disclosure is cited hereby. It is considered part of the specification. [Technical Field]

[0002] This invention relates to an optical film and an image display device. [Background technology]

[0003] Image display devices such as smartphones and tablet devices have been known for some time, but currently Development is underway on foldable image display devices. Typically, smartphones and tablets... While terminals and the like are covered with cover glass, if cover glass is used in an image display device, Although it has excellent hardness, there is a high risk of it breaking when you try to fold it. Therefore, when folding For image display devices that can display images, an optical film made of resin is used instead of a cover glass. This is being considered (see, for example, Japanese Patent Publication No. 2016-125063). [Overview of the project] [Problems that the invention aims to solve]

[0004] The optical film used in such foldable image display devices is an optical film Since the surface may be subjected to impact, impact resistance is required. Here, optical film When an impact is applied to the surface of the film, the surface of the optical film may become dented, and the image display may also be affected. In a display device, the display panel located inside the optical film (for example, an organic light-emitting diode) Components such as the back panel may be damaged.

[0005] Regarding the recesses on the surface of the optical film, there are recesses caused by the optical film itself and recesses caused by the adhesive layer disposed inside the image display device rather than the optical film. The "recesses caused by the optical film itself" means the recesses generated when an impact is applied to the surface of the optical film and the optical film itself is deformed by the impact. The "recesses caused by the adhesive layer" means that since the adhesive layer is soft, when an impact is applied to the surface of the optical film, the adhesive layer disposed inside the image display device rather than the optical film undergoes plastic deformation, and the optical film follows the plastic deformation of the adhesive layer, thereby generating recesses.

[0006] Therefore, in the optical film, when an impact is applied to the surface of the optical film, recesses caused by the optical film itself and recesses caused by the adhesive layer are suppressed, and excellent impact resistance is required such that members existing inside the image display device rather than the optical film are not damaged. However, at present, an optical film having such excellent impact resistance has not yet been obtained.

[0007] The present invention has been made to solve the above problems. That is, an object of the present invention is to provide a foldable optical film having excellent impact resistance and an image display device including the same.

Means for Solving the Problems

[0008] As a result of intensive studies on the above problems, the present inventors have found that in an optical film having a structure including a hard coat layer on one surface side of a resin substrate and a resin layer on the other surface side, when the film thickness of the resin layer is 50 μm or more and 300 μm or less, and at 25° C. and 500 Hz or more in the optical film ​​​​​​​​​​​​​​ The shear storage modulus G' and shear loss modulus G'' in the frequency range below 1000 Hz are used. We have found that excellent impact resistance can be obtained by keeping these within a predetermined range. The present invention is thus It was completed based on such knowledge.

[0009] According to one aspect of the present invention, a foldable light-transmitting optical A film comprising a resin substrate and a hard coat layer provided on the first surface side of the resin substrate. Furthermore, the film thickness provided on the second surface side of the resin substrate opposite to the first surface is 50 μm or less. The optical film comprises a resin layer of 300 μm or less, and the optical film is rated at 25°C and 500 Hz. The shear storage modulus G' in the frequency range above 1000 Hz exceeds 200 MPa and is 1200 MPa. The pressure is less than or equal to MPa, and the optical film is 25°C and 500Hz to 1000Hz. The shear loss modulus G'' in the frequency range is between 3 MPa and 150 MPa, and the optical fiber Film is provided.

[0010] In the optical film described above, the distance between opposing sides of the optical film is 30 mm. When the optical film is folded 180° 100,000 times, it does not crack. It is preferable that no breakage occurs.

[0011] In the above optical film, the resin substrate is a polyimide resin, a polyamide resin, and The base material may consist of a mixture of these.

[0012] According to another aspect of the present invention, a foldable image display device comprising a display panel and a front The optical film is positioned on the observer side of the display panel, and the optical film The hard coat layer of the film is located on the observer side of the resin substrate, in an image display device. Placement is provided.

[0013] In the above image display device, adhesive is placed between the optical film and the display panel. It may also have additional layers.

[0014] Even if the display panel in the above image display device is an organic light-emitting diode panel good. [Effects of the Invention]

[0015] According to one aspect of the present invention, a foldable optical film having excellent impact resistance is provided. It can be used. Furthermore, according to another aspect of the present invention, an image display comprising such an optical film We can provide the equipment. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic diagram of the optical film according to the embodiment. [Figure 2] Figure 2 is a schematic diagram of a solid shearing jig used to measure the shear storage modulus G' and the shear loss modulus G''. [Figure 3] Figures 3(A) to 3(C) schematically illustrate the process of a continuous folding test. [Figure 4] Figures 4(A) and 4(B) schematically illustrate the folding and static test. [Figure 5] Figure 5 is a schematic diagram of another optical film according to the embodiment. [Figure 6] This is a schematic diagram of the image display device according to the embodiment. [Modes for carrying out the invention]

[0017] Hereinafter, optical films and image display devices according to embodiments of the present invention will be described with reference to the drawings. I will explain while doing so. In this specification, terms such as "film" and "sheet" are used interchangeably. They are not distinguished from one another based solely on their nature. Therefore, for example, "film The term "sheet" is used to include components that are also called sheets. Figure 1 shows the light according to this embodiment. Figure 2 shows a schematic diagram of the film, with the shear storage modulus G' and shear loss modulus G'' being shown. This is a schematic diagram of the solid shearing jig used when measuring, and Figure 3 shows the continuous folding test. Figure 4 is a schematic diagram illustrating the child, and Figure 4 is a schematic diagram illustrating the folding and static test. Figure 5 is a schematic diagram of another optical film according to this embodiment.

[0018] <<<Optical Film>>> The optical film 10 shown in Figure 1 is used in an image display device and is foldable. It is possible and has light transmittance. In this specification, "light transmittance" means light This refers to the property of transmitting light, for example, a total light transmittance of 50% or more, preferably 70% or more. more preferably 80% or more, particularly preferably 90% or more. Light transmittance and It does not necessarily have to be transparent; it can be semi-transparent.

[0019] The optical film 10 consists of a resin substrate 11 and a first surface 11A side of the resin substrate 11. The hard coat layer 12 and the second surface 1 of the resin substrate 11, which is the surface opposite to the first surface 11A. It comprises a resin layer 13 provided on the 1B side. Note that the resin group in the resin layer 13 A release film may be provided on the side opposite to the side facing material 11. However, the present invention The physical properties of the optical film 10 described in the detailed document are as follows: This is the value in its current state, and the release film is peeled off when in use, so the release film It shall not constitute part of the optical film.

[0020] In Figure 1, the surface 10A of the optical film 10 is the surface 12A of the hard coat layer 12. In this specification, the surface of the optical film is one side of the optical film. Since it is used to mean the surface, the side opposite the surface of the optical film is the optical film. To distinguish it from the surface of the film, it shall be referred to as the back surface. The back surface 10B of the optical film 10 is This is the surface 13A of the resin layer 13 that is opposite to the surface on the resin substrate 11 side.

[0021] In the optical film 10, at 25°C and in the frequency range of 500Hz to 1000Hz, The shear storage modulus G' is above 200 MPa and below 1200 MPa. When the shear storage modulus G' of the optical film exceeds 200 MPa, an impact is applied to the surface of the optical film. When this happens, not only does the optical film itself deform, but also the inside of the image display device is more sensitive to the optical film. Even when an adhesive layer is present, plastic deformation of the adhesive layer can be suppressed. If the shear storage modulus G' of the optical film is 1200 MPa or less, the light during folding Cracking of the optical film can be suppressed. The lower limit of the shear storage modulus G' of the optical film 10 is 40 It is preferable that the pressure be 0 MPa or higher, and more preferably 500 MPa or higher. It is desirable. By setting such a lower limit, better shock resistance can be obtained. Optical The upper limit of the shear storage modulus G' of film 10 is preferably less than 800 MPa. By setting such an upper limit, good recovery is possible when the item is folded, left to stand, and then opened again. It can be obtained.

[0022] In the optical film 10, at 25°C and in the frequency range of 500Hz to 1000Hz, The shear loss modulus G'' is between 3 MPa and 150 MPa. Optical film If the shear loss modulus G'' is less than 3 MPa, the shock absorption performance may be reduced. Furthermore, if the shear loss modulus G'' of the optical film exceeds 150 MPa, the hardness of the resin layer There is a possibility that it will decrease. The lower limit of the shear loss modulus G'' of the optical film 10 is 20 It is preferable that the shear loss modulus of the optical film 10 is G'' or higher. The upper limit is set at 130 MPa or less, from the perspective of making the optical film 10 thinner. Preferably, the pressure is 100 MPa or less.

[0023] The shear storage modulus G' and shear loss modulus G'' are measured using a dynamic viscoelasticity measuring device (DMA). Therefore, it can be measured. Using a dynamic viscoelasticity measuring device (DMA), optical film 1 When measuring the shear storage modulus G' and shear loss modulus G'' of 0, first, an optical filter is used. A sample is obtained by punching out a 10mm x 5mm rectangular shape from Rum 10. Then, this sample Prepare two samples and use a dynamic viscoelasticity measuring device (product name "Rheogel-E4000", UBM Corporation). It is attached to the solid shearing jig, which is an option for the (manufactured by) company. Specifically, as shown in Figure 2. The solid shearing jig 20 consists of a single metal solid shearing plate 21 (middle plate) with a thickness of 1 mm, and The solid shear plate 21 is equipped with two L-shaped brackets 22 (outer plates) positioned on both sides, and the solid shear plate One sample S is sandwiched between the plate 21 and one L-shaped bracket 22, and the solid shear plate 21 and the other The other sample S is sandwiched between the L-shaped bracket 22. In this case, the resin layer is on the solid shear plate 21 side. Then, insert sample S so that the hard coat layer is on the L-shaped bracket 22 side. Then, screw 23 Then, tighten the L-shaped brackets to fix the sample S in place. Next, the dynamic viscoelasticity measuring device (product name " Rheogel-E4000 (manufactured by UBM Co., Ltd.) has upper and lower zippers After attaching the tensile testing chuck, a solid shear is applied between the upper and lower chucks. Attach the jig with a 20mm distance between the chucks. The distance between the chucks is between the upper chuck and the lower chuck. This is the distance between the chucks. Then, the set temperature is 25°C and the temperature is raised at a rate of 2°C / min. In this state, while fixing the solid shear plate, apply a strain of 1% and a frequency of 500Hz to two L-shaped brackets. Dynamic viscoelasticity measurement of a solid at 25°C while applying longitudinal vibrations in the range of z to 1000 Hz. The shear storage modulus G' and shear loss modulus G'' of the optical film 10 are measured. Here, shear storage in optical film in the frequency range of 500 Hz to 1000 Hz. The stored modulus of elasticity G' and the shear loss modulus of elasticity G'' were measured for L-shaped fittings at frequencies of 500Hz and 750Hz. A longitudinal vibration of 950 Hz is applied to the optical film at each frequency, and the shearing of the optical film is measured. The storage modulus G' and the shear loss modulus G'' are measured, and these shear storage modulus G' and Then, calculate the arithmetic mean of the shear loss modulus G'', and repeat this measurement three times, The three arithmetic mean values ​​obtained are then given their arithmetic mean values. The reason for specifying a frequency range of 0Hz to 1000Hz is that the frequencies in this range are within a few centimeters. When an object is dropped from a height, the surface of the optical film changes from a few microns to tens of microns. It is a frequency at which deformation occurs, and the display panel located inside the image display device is more sensitive than the optical film. This is because it is a frequency that can cause damage to things like the lubricant.

[0024] Another film, such as a polarizing plate, is provided on one side of the optical film 10 via an adhesive layer or bonding layer. If it is peeled off, remove the adhesive layer and other films together before shearing and storing. The elastic modulus G' and shear loss elastic modulus G'' shall be measured. The peeling of other films shall be For example, this can be done as follows: First, apply an adhesive layer or bonding layer to the optical film. The laminate with other films attached is heated with a dryer, and the optical film and other films Insert the tip of the cutter blade into the area that appears to be the interface and slowly peel it off. By repeatedly heating and peeling, the adhesive layer, bonding layer, and other films can be removed. It can be done. Furthermore, even if such a peeling process is performed, the shear storage modulus G' and shear loss This does not significantly affect the result of the elastic modulus G''.

[0025] The optical film 10 is foldable, but specifically, the optical film 10 In contrast, if the folding test (continuous folding test) described below is repeated 100,000 times... However, it is preferable that no cracks or breaks occur in the optical film, and a continuous folding test is performed. Even after 200,000 repetitions, the optical film 10 will not crack or break. It is more preferable that the optical film does not crack even after being repeated 1 million times. It is even more preferable that no breakage occurs. A continuous folding test is performed on the optical film 10. If the optical film 10 cracks or other damage occurs after 100,000 repetitions, the optical film 1 The foldability of 0 is insufficient. In the continuous folding test, the hard coat layer 12 is on the inside. The optical film 10 may be folded in such a way, and the hard coat layer 12 may be on the outside The optical film 10 may be folded so that it becomes the side, but in either case However, it is preferable that no cracks or breaks occur in the optical film.

[0026] Another film, such as a polarizing plate, is provided on one side of the optical film 10 via an adhesive layer or bonding layer. If it is attached, the adhesive layer or bonding layer and other film can be attached using the same method as described above. After peeling off the layer, a continuous folding test shall be performed. Even so, this will not significantly affect the results of the continuous folding test.

[0027] The continuous folding test is performed as follows: As shown in Figure 3(A), the continuous folding test In the test, first, the edge 10C of the optical film 10 and the edge opposite the edge 10C The optical film 10 is fixed to the optical film 10 by the fixing parts 30 which are arranged in parallel. It may be any shape, but the optical film 10 in the continuous folding test is rectangular. For example, a rectangle measuring 30 mm x 100 mm is preferable. Also, as shown in Figure 3(A) As described above, the fixing part 30 is capable of sliding horizontally.

[0028] Next, as shown in Figure 3(B), by moving the fixing parts 30 closer to each other, The optical film 10 is deformed to fold, and further, as shown in Figure 3(C), the optical film The distance between the two opposing sides fixed by the fixing part 30 of film 10 is 30 mm. After moving the fixing part 30, move the fixing part 30 in the reverse direction to deform the optical film 10. To resolve the issue.

[0029] As shown in Figures 3(A) to (C), the optical film 10 can be moved by moving the fixing part 30. It can be folded 180°. Also, the bent portion 10E of the optical film 10 is fixed to the fixing portion 30. A continuous folding test is performed so that it does not protrude from the lower end, and when the fixing part 30 is closest to the ground... By controlling the spacing to 30 mm, the distance between the two opposing sides of the optical film 10 is 3 It can be set to 0mm. In this case, the outer diameter of the bent part 10E is considered to be 30mm. Note that optical fill The thickness of M10 is sufficiently small compared to the spacing of the fixing parts 30 (30 mm), The results of the continuous folding test of the optical film 10 show shadows due to differences in the thickness of the optical film 10. It can be considered that no vibration is received. In the optical film 10, the optical film 10 The test involved repeatedly folding the material 180° so that the distance between opposing sides was 30mm, 100,000 times. It is preferable that no cracks or breaks occur when this happens, but the opposing sides of the optical film 10 A continuous folding test was repeated 100,000 times, in which the part was folded 180° so that the gap between the parts was 6 mm. It is more preferable that no cracking or breakage occurs when the optical film 10 is facing each other. A continuous folding test was repeated 100,000 times, in which the material was folded 180° so that the gap between the edges was 3 mm. It is even more preferable that no cracking or fracturing occurs when the optical film 10 is opposed A continuous folding test is performed 100,000 times, in which the material is folded 180° so that the gap between the edges is 2 mm. It is most desirable that no cracks or breaks occur when the material is returned to its original state.

[0030] In the optical film 10, as shown in Figure 4(A), the edge of the optical film 10 10C and the opposite side 10D are separated by a distance of 30 The optical film 10 is fixed by fixing parts 35 which are arranged in parallel so as to be mm apart. A folded static test was conducted, in which the product was left undisturbed at 70°C for 240 hours in its folded state, as shown in Figure 4(B). As shown, by removing the fixing part 35 from the edge 10D after the folding and static test, The folded state is released, and after 30 minutes at room temperature, the optical film 10 When measuring the opening angle θ, which is the angle at which it naturally opens, the opening angle θ of the optical film 10 is 10 It is preferable that the opening angle θ is 0° or greater. Furthermore, the larger the opening angle θ, the better the restorative properties. This means that the maximum angle is 180°. The folding static test is performed with the hard coat layer 12 on the inside. The optical film 10 may be folded in such a way, and the hard coat layer 12 The optical film 10 may be folded so that it faces outwards, but in either case Even if present, it is preferable that the opening angle θ is 100° or more.

[0031] The surface 10A of the optical film 10 (surface 12A of the hard coat layer 12) conforms to JIS K5 Hardness as measured by the pencil hardness test specified in 600-5-4:1999 (pencil hardness) ) is preferably B or higher, and more preferably H or higher. However, pencil hardness The test involved applying a 1kg load to a pencil and moving it at a speed of 1mm / second. The test shall be conducted in the following manner. Pencil hardness is determined by whether or not scratches are made on the surface of the optical film during the pencil hardness test. The highest hardness level among those not found will be used. Note that when measuring pencil hardness, multiple pencils with different hardness levels will be used. This procedure is performed using the following method: each pencil is subjected to a pencil hardness test five times, and at least four of those five tests are performed using an optical filter. If the surface of the film is not scratched, then with a pencil of this hardness, the surface of the optical film It is determined that no damage occurred. The above scratches were found on the surface of the optical film that underwent the pencil hardness test. This refers to objects that can be seen when observed under fluorescent light.

[0032] The optical film 10 preferably has a yellow index (YI) of 15 or less. When the YI of optical film 10 exceeds 15, the yellowish tint of the optical film becomes noticeable, and its transparency is impaired. It may not be suitable for the required application. The yellow index (YI) is a spectral light Temperature meter (product name "UV-3100PC", manufactured by Shimadzu Corporation, light source: tungsten lamp) The values ​​were measured using a BB lamp and a deuterium lamp. The yellow ink of optical film 10. It is more preferable that the upper limit of DEX (YI) be 10 or less.

[0033] Furthermore, on one side of the optical film 10, another film such as a polarizing plate can be attached via an adhesive layer or bonding layer. If a film is provided, the adhesive layer or bonding layer is applied together with other materials in the same manner as described above. The film shall be peeled off before measuring the yellow index (YI). Even with such a peeling process, the measurement of the yellow index (YI) is not significantly affected. There is no impact.

[0034] To adjust the yellow index (YI) of the optical film 10, for example, a resin base The material 11 and the resin layer 13 may contain a blue pigment, which is the complementary color to yellow. Therefore, even in cases where yellowing is a problem, by using a polyimide substrate, By incorporating a blue dye into the resin substrate 11 or resin layer 13, the yellow color of the optical film is reduced. It can lower the Dex (YI).

[0035] The blue pigment mentioned above may be either a pigment or a dye, for example, optical fiber When film 10 is used in organic light-emitting diode display devices, it is required to have both light resistance and heat resistance. It is preferable that the above blue pigments include polycyclic organic pigments and metal complex organic pigments, etc. Compared to molecular dispersion, the degree of molecular cleavage caused by ultraviolet light is less, and the light resistance is significantly superior. Preferably used in applications where photophobicity is required, and more specifically, phthalocyanine-based organic pigments, etc. These are preferred. However, since the pigment is dispersed in the solvent, transparency due to particle scattering may occur. Since sensory inhibition exists, it is preferable to place the particle size of the pigment dispersion within the Rayleigh scattering range. On the other hand, when transparency of the optical film is important, the blue dye mentioned above is a solvent-resistant dye. It is preferable to use a dye that is molecularly dispersed.

[0036] The transmittance of light with a wavelength of 380 nm through the optical film 10 is preferably 8% or less. If the above transmittance of the optical film exceeds 8%, when the optical film is used in a mobile device, The polarizer may be more susceptible to degradation if exposed to ultraviolet light. The above transmittance is measured by a spectrophotometer. (Product name "UV-3100PC", manufactured by Shimadzu Corporation, light source: tungsten lamp) It can be measured using a deuterium lamp. The above transmittance is obtained by taking three measurements. The arithmetic mean of the values ​​is taken. The upper limit of the above transmittance of optical film 10 is 5%. This is preferable. The above transmittance of the optical film 10 is determined by the ultraviolet absorption in the resin layer 13, which will be described later. This can be achieved by adjusting the amount of the agent added, etc.

[0037] The haze value (total haze value) of the optical film 10 is preferably 2.5% or less. If the above haze value of the optical film exceeds 2.5%, the optical film used in mobile devices will be deemed unsuitable. In some cases, the image display surface may appear white. The above haze value must be 1.5% or less. More preferably, it is 1.0% or less.

[0038] The above haze values ​​were obtained using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Laboratory). It can be measured using a method compliant with JIS K7136:2000. The haze value is measured after cutting to a size of 50mm x 100mm, and ensuring there are no curls or wrinkles. The optical film should be placed so that the surface side is facing the non-light source, free from fingerprints, dust, etc. Three measurements are taken for each sheet, and the arithmetic mean of the values ​​obtained from the three measurements is used. In this context, "measuring three times" does not mean measuring the same location three times, but rather measuring three different locations. This means that the optical film 10 is flat. The surface is flat, the resin layer 12 is also flat, and the variation in film thickness is within ±10%. Therefore, by measuring the haze value at three different locations on the cut optical film, It is thought that the average value of the haze value across the entire surface of the optical film can be obtained. The variation in values ​​is due to the fact that even when the measurement target is a long length of 1m x 3000m, the 5-inch smartphone... Even if the size is about that of a 'fon', the tolerance is within ±10%. Note that the optical film is the above size. If it cannot be cut out, for example, the HM-150 has an entrance opening of 20mmφ for measurement. Therefore, a sample size of 21 mm or more in diameter is required. For this reason, 22m The optical film may be cut to a size of m x 22 mm or larger as appropriate. If the difference is small, gradually shift or change the angle while keeping the light source spot within the range that does not move away. This allows for three measurement points.

[0039] Furthermore, on one side of the optical film 10, another film such as a polarizing plate can be attached via an adhesive layer or bonding layer. If a film is provided, the adhesive layer or bonding layer is applied together with other materials in the same manner as described above. After peeling off the film, wipe off any dirt from the adhesive layer or bonding layer thoroughly with alcohol. The haze value shall be measured. Even if such a peeling process is performed, the haze It does not significantly affect the measurement of the value.

[0040] In recent years, the backlight of image display devices such as personal computers and tablet devices has been Light-emitting diodes (LEDs) are being actively adopted as the power source. However, this light-emitting diode emits a strong light called blue light. Blue light is light with a wavelength of 380-495nm and has properties similar to ultraviolet light, and is strong. Because it possesses energy, it reaches the retina without being absorbed by the cornea or lens, thus affecting the retina. It is said to cause damage, eye strain, and adverse effects on sleep. Therefore, optical film When applied to an image display device, it does not affect the color of the display screen, and blue It is preferable that the light-blocking properties are excellent. Therefore, the view is to block blue light. From this point, the optical film 10 has a spectral transmittance of less than 1% at a wavelength of 380 nm, and wave The spectral transmittance at a length of 410 nm is less than 10%, and the spectral transmittance at a wavelength of 440 nm is less than 10%. A ratio of 70% or higher is preferable. The spectral transmittance at the above wavelength of 380 nm is 1% or less. If the light is above, or if the spectral transmittance at a wavelength of 410 nm is 10% or more, then blue - Problems caused by light may not be resolved, and the spectral transmittance at a wavelength of 440 nm is 7 If the value is less than 0%, it will affect the color of the display screen of an image display device using optical film. This is because it can happen. The optical film 10 is made of blue light wavelengths, It absorbs light in the wavelength range of 410 nm or less sufficiently, while filling in light with wavelengths of 440 nm or more. It allows light to pass through without affecting the color of the display screen, and has excellent blue light blocking properties. This can be done. In addition, an optical film 1 with excellent blue light shielding properties When 0 is applied to an organic light-emitting diode (OLED) display device as an image display device, It is also effective in suppressing the degradation of light-emitting diode elements.

[0041] The light transmittance of optical film 10 is almost 0% up to a wavelength of 380 nm, and at a wavelength of 410 nm... Light transmission gradually increases from nm upwards, and then increases sharply around a wavelength of 440 nm. It is preferable that the wavelength is divided between 410 nm and 440 nm. It is preferable that the light transmittance changes in a way that follows a sigmoid curve. The above wavelength is 380n. The spectral transmittance at m is more preferably less than 0.5%, and even more preferably less than 0.2%. Yes, and more preferably the spectral transmittance at a wavelength of 410 nm is less than 7%, more preferably 5%. It is less than %, and the spectral transmittance at a wavelength of 440 nm is more preferably 75% or more, and even more preferably The percentage is over 80%. Furthermore, the optical film 10 has spectral transmission at a wavelength of 420 nm. It is preferable that the excess is less than 50%. By satisfying this relationship between spectral transmittance, The optical film 10 exhibits a rapid increase in transmittance around a wavelength of 440 nm, resulting in a display image. It is possible to achieve extremely excellent blue light blocking without affecting the color of the surface.

[0042] The spectral transmittance of optical film 10 at a wavelength of 380 nm is less than 0.1%. It is more preferable that the spectral transmittance at a wavelength of 410 nm is less than 7%. Furthermore, it is more preferable that the spectral transmittance at a wavelength of 440 nm is 80% or higher.

[0043] The optical film 10 has a wavelength range of 415-435 nm obtained using the least squares method. It is preferable that the slope a of the hyperspectral signal is a > 2.0. If so, in the wavelength range of blue light, for example, in the wavelength range of 415-435nm... This can result in insufficient light blocking and a weakened blue light blocking effect. It's possible that the light source is cutting out too much of the wavelength range (wavelengths 415-435nm). In that case, the backlight and emission wavelength range of the image display device (for example, the wavelength of OLED 43) Interference with light emission from 0nm may cause problems such as poor color reproduction. The above slope a can be measured, for example, with a spectrometer capable of measuring in 0.5% increments. Using the product name "UVPC-2450" (manufactured by Shimadzu Corporation), a minimum of 5 points was measured within a 1nm margin. The transmittance data for each component can be calculated by measuring it between 415 and 435 nm. .

[0044] The optical film 10 preferably has a blue light shielding rate of 40% or more. - If the light shielding rate is less than 40%, the problems caused by the aforementioned blue light will not be sufficiently addressed. There are some issues that cannot be resolved. The above blue light shielding rate is, for example, JIS T7333: This value is calculated using the 2005 method. Note that such blue light shielding rates are, for example, This is achieved by including a sesamol-type benzotriazole monomer, as described later, in the resin layer 13. It is possible.

[0045] The applications of the optical film 10 are not particularly limited, but some applications of the optical film 10 include: For example, smartphones, tablet devices, personal computers (PCs), wearables Image display devices such as digital terminals, digital signage, televisions, and car navigation systems The optical film 10 is also suitable for automotive applications. In terms of form, applications requiring flexibility such as foldable and rollable designs are suitable. It is also preferable.

[0046] The optical film 10 may be cut to a desired size, or it may be in roll form. Good. If the optical film 10 is cut to the desired size, the size of the optical film This is not particularly limited and is determined appropriately according to the size of the display surface of the image display device. Specifically The size of the optical film 10 is, for example, between 2.8 inches and 500 inches. It may be. In this specification, “inch” means when the optical film is rectangular in shape. It refers to the length of the diagonal, the diameter in the case of a circle, and the diameter in the case of an ellipse. This represents the average value of the sum of the minor and major axes. Here, the optical film is rectangular in shape. In this case, the aspect ratio of the optical film when determining the above inches is as the display screen of the image display device. There are no particular limitations as long as there are no problems. For example, vertical:horizontal = 1:1, 4:3, 16:10, 16 Examples include :9, 2:1, etc. However, in particular, automotive applications and digital sites with a strong design are... In signage, the aspect ratio is not limited to this. Also, the size of the optical film 10 If it is large, cut it to A5 size (148mm x 210mm) from any position. Next, the data will be cut to the size of each measurement item.

[0047] The location of the optical film 10 in the image display device may be inside the image display device. It is acceptable, but it is preferable that it be near the surface of the image display device. In such cases, the optical film 10 is a cover film used in place of a cover glass. It functions in this way.

[0048] <<Resin base material>> The resin substrate 11 is a substrate made of a light-transmitting resin. The thickness of the resin substrate 11 is It is preferable that the thickness is between 10 μm and 100 μm. If the temperature is too high, the curl of the optical film may become excessive, and the hardness may also be insufficient. Furthermore, when optical films are manufactured using a roll-to-roll method, wrinkles are more likely to occur. This may lead to a deterioration in appearance. On the other hand, if the thickness of the resin substrate exceeds 100 μm The folding performance of the optical film becomes insufficient, and it fails to meet the requirements of the continuous folding test. Furthermore, the optical film becomes heavier, which is undesirable in terms of weight reduction. (Thickness of the resin substrate) This involves using a scanning electron microscope (SEM) to photograph the cross-section of the resin substrate, and then using the image of that cross-section to... The film thickness of the resin substrate is measured at 20 locations, and the arithmetic mean of the film thicknesses at these 20 locations is taken. The method for taking cross-sectional photographs of the substrate is the same as the method for taking cross-sectional photographs of the hard coat layer. The lower limit of the substrate 11 is more preferably 25 μm or more, and the upper limit of the resin substrate 11 is 80 μm It is more preferable that it be less than or equal to m.

[0049] Examples of resins constituting the resin substrate 11 include polyimide resin and polyamideimide resin. Fat, polyamide resin, polyester resin (for example, polyethylene terephthalate resin and poly Examples include ethylene naphthalate resin, or mixtures of two or more of these resins. Among these, not only is it less likely to crack or break in continuous folding tests, but Furthermore, it possesses excellent hardness and transparency, as well as superior heat resistance, and can be further improved by firing. From the viewpoint of being able to impart excellent hardness and transparency, polyimide resin, polyamide resin Fat, or a mixture thereof, is preferred.

[0050] Polyimide resins are obtained by reacting a tetracarboxylic acid component with a diamine component. Therefore, polyamic acid is obtained by polymerization of the tetracarboxylic acid component and the diamine component. Imidation is preferable. Imidation can be carried out by thermal imidation or chemical imidation. Good. It can also be produced using a method that combines thermal imidation and chemical imidation. The imide resin may be an aliphatic polyimide resin, but it may also be an aromatic resin containing an aromatic ring. A polyimide resin is preferred. Aromatic polyimide resins are tetracarboxylic acid compounds. The compound contains an aromatic ring in at least one of the fraction and the diamine component.

[0051] As a specific example of the tetracarboxylic acid component, tetracarboxylic dianhydride is preferably used. , cyclohexanetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride Dicyclohexane-3,4,3',4'-tetracarboxylic dianhydride, pyromellitic acid Dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2', 3,3'-Benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyl Tetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride , 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2 ,3-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl ) ether dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 1,1 -Bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl) Phenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2 ,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluor Lopropane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3 ,3,3-Hexafluoropropane dianhydride, 1,3-Bis[(3,4-Dicarboxy) [Benzoyl]benzene dianhydride, 1,4-bis[(3,4-dicarboxy)benzoyl] Benzene dianhydride, 2,2-bis{4-[4-(1,2-dicarboxy)phenoxy] phenyl}propane dianhydride, 2,2-bis{4-[3-(1,2-dicarboxy)pheno Xy]phenyl}propane dianhydride, bis{4-[4-(1,2-dicarboxy)pheno Xy]phenyl}ketone dianhydride, bis{4-[3-(1,2-dicarboxy)phenoxy [C]phenyl}ketone dianhydride, 4,4'-bis[4-(1,2-dicarboxy)pheno Xy]biphenyl dianhydride, 4,4'-bis[3-(1,2-dicarboxy)phenoxy ] Biphenyl dianhydride, bis{4-[4-(1,2-dicarboxy)phenoxy]phen {Lu}ketone dianhydride, bis{4-[3-(1,2-dicarboxy)phenoxy]phenyl }Ketone dianhydride, bis{4-[4-(1,2-dicarboxy)phenoxy]phenyl} Sulfone dianhydride, bis{4-[3-(1,2-dicarboxy)phenoxy]phenyl} Sulfone dianhydride, bis{4-[4-(1,2-dicarboxy)phenoxy]phenyl} Sulfide dianhydride, bis{4-[3-(1,2-dicarboxy)phenoxy]phenyl Sulfide dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride Substance, 3,4'-(hexafluoroisopropylidene)diphthalic anhydride, 3,3'-(he Xafluoroisopropylidene diphthalic anhydride, 2,3,6,7-naphthalenetetra Carboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2, 5,6-Naphthalenetetracarboxylic dianhydride, 1,2,3,4-Benzenetetracarb 3,4,9,10-Perylenetetracarboxylic acid dianhydride, 2,3,6,7 -Anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracal Examples include dianhydrides of bonate. These can be used individually or in mixtures of two or more. Cut.

[0052] Specific examples of diamine components include p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 3,3'-diaminodiphenyl ether, 3,4'-diamino Diphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl Phenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl Phenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl Nylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophen Non, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4 '-diaminobenzanilide, 3,3'-diaminodiphenylmethane, 4,4'-diamino Nodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-di(3-aminof 2,2-(4-aminophenyl)propane, 2-(3-aminophenyl)propane Nyl)-2-(4-aminophenyl)propane, 2,2-di(3-aminophenyl)-1 ,1,1,3,3,3-Hexafluoropropane, 2,2-Di(4-aminophenyl)- 1,1,1,3,3,3-Hexafluoropropane, 2-(3-aminophenyl)-2- (4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 1,1- di(3-aminophenyl)-1-phenylethane, 1,1-di(4-aminophenyl)- 1-Phenylethane, 1-(3-aminophenyl)-1-(4-aminophenyl)-1- Phenylethane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4- aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4 -Bis(4-aminophenoxy)benzene, 1,3-bis(3-aminobenzoyl)bene Zen, 1,3-bis(4-aminobenzoyl)benzene, 1,4-bis(3-aminoben Zoyl(benzene), 1,4-bis(4-aminobenzoyl)benzene, 1,3-bis(3 -amino-α,α-dimethylbenzyl)benzene, 1,3-bis(4-amino-α,α- Dimethylbenzyl)benzene, 1,4-bis(3-amino-α,α-dimethylbenzyl) Benzene, 1,4-bis(4-amino-α,α-dimethylbenzyl)benzene, 1,3- Bis(3-amino-α,α-ditrifluoromethylbenzyl)benzene, 1,3-bis( 4-amino-α,α-ditrifluoromethylbenzyl)benzene, 1,4-bis(3-A Mino-α,α-ditrifluoromethylbenzyl)benzene, 1,4-bis(4-amino- α,α-Ditrifluoromethylbenzyl)benzene, 2,6-Bis(3-aminophenoxy (c) Benzonitrile, 2,6-bis(3-aminophenoxy)pyridine, N,N'-bis (4-aminophenyl)terephthalamide, 9,9-bis(4-aminophenyl)fluoramide Len, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-ditrifluoro Methyl-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl Phenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dimethyl- 4,4'-diaminobiphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-Bis(4-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy [4-(4-aminophenoxy)phenyl]ketone, bis[ 4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy [C)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone, Bis[4-(4-aminophenoxy)phenyl]sulfone, Bis[4-(3-aminophen [(4-(4-aminophenoxy)phenyl] ether, bis[4-(4-aminophenoxy)phenyl] ether , 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4 -(4-aminophenoxy)phenyl]propane, 2,2-bis[3-(3-aminophen [Noxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoro Propane, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,3 -Bis[4-(4-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3 -aminophenoxy)benzoyl]benzene, 1,4-bis[4-(4-aminophenoxy [C)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)-α,α-di [methylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)-α,α-di Methylbenzylbenzene, 1,4-bis[4-(3-aminophenoxy)-α,α-di Methylbenzylbenzene, 1,4-bis[4-(4-aminophenoxy)-α,α-di [methylbenzyl]benzene, 4,4'-bis[4-(4-aminophenoxy)benzoyl ]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl )phenoxy]benzophenone, 4,4'-bis[4-(4-amino-α,α-dimethyl [Benzyl)phenoxy]diphenylsulfone, 4,4'-bis[4-(4-aminopheno [Xy)phenoxy]diphenylsulfone, 3,3'-diamino-4,4'-diphenoxy Benzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 3, 3'-diamino-4-phenoxybenzophenone, 3,3'-diamino-4-biphenoxy Cibenzophenone, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-the Tramethyl-1,1'-spirobindan,6,6'-bis(4-aminophenoxy)- 3,3,3',3'-Tetramethyl-1,1'-Spirobindan, 1,3-Bis(3- (Aminopropyl)tetramethyldisiloxane, 1,3-bis(4-aminobutyl)tetra Methyldisiloxane, α,ω-bis(3-aminopropyl)polydimethylsiloxane, α ω-bis(3-aminobutyl)polydimethylsiloxane, bis(aminomethyl)ether Lu, bis(2-aminoethyl) ether, bis(3-aminopropyl) ether, bis( 2-aminomethoxy)ethyl]ether, bis[2-(2-aminoethoxy)ethyl]ether ether, bis[2-(3-aminopropyl)ethyl]ether, trans-cyclohexyl Sandiamine, trans-1,4-bismethylenecyclohexanediamine, 2,6-bi Su(aminomethyl)bicyclo[2,2,1]heptane, 2,5-bis(aminomethyl)bi Cyclo[2,2,1]heptane, or some of the hydrogen atoms on the aromatic ring of the above diamine All of them are fluoro groups, methyl groups, methoxy groups, trifluoromethyl groups, or trifluoro Diamines substituted with substituents selected from the rautomethoxy group can also be used. It can be used alone or in combination of two or more types.

[0053] From the standpoint of improving light transmittance and rigidity, aromatic polyimide resins are used. It contains a ring and (i) a fluorine atom, (ii) an aliphatic ring, and (iii) aromatic rings together A polyimide system comprising at least one selected from the group consisting of linking groups that cleave electron conjugation. Preferably a resin, a polyimide-based resin comprising at least one of (i) and (iii). It is more preferable that it be a lipid. Including aromatic rings in polyimide resins increases orientation and rigidity. While properties improve, transmittance tends to decrease due to the absorption wavelength of the aromatic ring. (Polyimide) (i) If the resin contains fluorine atoms, charge transfer within the polyimide framework is difficult. The light transmittance is improved because it can be made smaller. Also, polyimide resins are (ii) fat When a group ring is present, the charge within the framework is broken by interrupting the conjugation of π electrons within the polyimide framework. Because it can inhibit movement, light transmittance is improved. Furthermore, polyimide resins ( iii) If it contains a linking group that cleaves the electron conjugation between aromatic rings, within the polyimide skeleton Is it because breaking the conjugation of π electrons can inhibit the movement of charge within the framework? This improves light transmittance. As for linking groups that cleave the electron conjugation between aromatic rings, For example, ether bond, thioether bond, carbonyl bond, thiocarbonyl bond, ami Sulfonyl bonds, sulfonyl bonds, and sulfinyl bonds, and even when substituted with fluorine. Examples include good divalent linking groups such as alkylene groups.

[0054] Among these, the polyimide resin must contain an aromatic ring and a fluorine atom. However, it is preferably used because it improves light transmittance and rigidity. Contains fluorine atoms. The fluorine atom content in polyimide resins is determined by X-ray light on the surface of the polyimide resin. The ratio of fluorine atoms (F) to carbon atoms (C) (F / C), measured by electron spectroscopy, It is preferable that it be 0.01 or higher, and more preferably 0.05 or higher. On the other hand, If the oxyatom content is too high, the inherent heat resistance and other properties of the polyimide resin may decrease. Therefore, if the ratio of the number of fluorine atoms (F) to the number of carbon atoms (C) (F / C) is 1 or less, It is preferable that it is present, and more preferably 0.8 or less. Here, X-ray photoelectron spectroscopy The above ratios obtained by XPS measurements are obtained using an X-ray photoelectron spectrometer (e.g., Thermo Sc). Atomic percentage values ​​of each atom measured using the Intific Theta Probe. It can be calculated from this.

[0055] Furthermore, more than 70% of the hydrogen atoms bonded to carbon atoms in polyimide resins are fragrances. The fact that it is a polyimide resin with hydrogen atoms directly bonded to the group ring improves light transmittance. Furthermore, it is preferably used from the viewpoint of improving rigidity. Carbon atoms contained in polyimide resins The proportion of hydrogen atoms directly bonded to the aromatic ring out of the total number of hydrogen atoms bonded is Furthermore, it is preferable that the content be 80% or more, and more preferably 85% or more. More than 70% of the hydrogen atoms bonded to carbon atoms in imides are directly bonded to aromatic rings. In the case of polyimide, which is composed of hydrogen atoms, even after a heating process in the atmosphere, for example, 2 Even when stretched at temperatures above 0°C, the optical properties, especially the total light transmittance and the yellow index (Y) remain unchanged. I) is preferable because it shows little change. In the case of polyimides, where more than 70% of the elementary atoms are hydrogen atoms directly bonded to the aromatic ring. It is presumed that because of its low reactivity with oxygen, the chemical structure of polyimide resins is less likely to change. The base material, made of polyimide resin, utilizes its high heat resistance, and processing steps involving heating are performed. Although often used in necessary devices, the carbon atoms contained in polyimide resins Polyimide systems in which more than 70% of the bonded hydrogen atoms are hydrogen atoms directly bonded to the aromatic ring. If the material is a resin, these subsequent processes must be carried out under an inert atmosphere to maintain transparency. Since this does not occur, there is the advantage of being able to reduce equipment costs and the costs associated with atmosphere control. Here, among the total number of hydrogen atoms bonded to carbon atoms in the polyimide resin, The proportion of hydrogen atoms (number) directly bonded to the aromatic ring is determined by the decomposition of polyimide using high-performance liquid chromatography. This can be determined using matrixing, gas chromatography-mass spectrometry, and NMR. For example, the sample is decomposed with an alkaline aqueous solution or supercritical methanol, and obtained The resulting degradation products were separated by high-performance liquid chromatography, and each separated peak was subjected to qualitative analysis. This is performed using gas chromatography-mass spectrometry and NMR, and high-performance liquid chromatography. By quantifying using this method, the aromatic rings among the total number of hydrogen atoms contained in polyimide can be determined. It is possible to determine the proportion (number) of hydrogen atoms that directly bond to each other.

[0056] Furthermore, in terms of improving light transmittance and rigidity, polyimide resins are suitable. In particular, selected from the group consisting of structures represented by the following general formulas (1) and (3). It is preferable that it has at least one type of structure.

[0057] [ka]

[0058] In the above general formula (1), R 1 R is a tetravalent group which is a tetracarboxylic acid residue. 2 is, t rans-cyclohexanediamine residue, trans-1,4-bismethylenecyclohex Sandiamine residue, 4,4'-diaminodiphenylsulfone residue, 3,4'-diaminodi A phenylsulfone residue and a divalent group represented by the following general formula (2) are selected from the group. It represents at least one divalent group. n represents the number of repeating units and is 1 or greater. In the detailed explanation, "tetracarboxylic acid residue" refers to a tetracarboxylic acid with four carboxyl groups. This refers to a residue from which the syl group has been removed, specifically a residue from which the acid dianhydride structure has been removed from a tetracarboxylic dianhydride. It represents the same structure as [another example]. Also, a "diamine residue" is a diamine with two amino groups removed. It refers to a residue.

[0059] [ka] In the above general formula (2), R 3 and R 4 Each of them independently consists of a hydrogen atom and an alkyl group. Represents a group or a perfluoroalkyl group.

[0060] [ka]

[0061] In the above general formula (3), R 5 This is a cyclohexanetetracarboxylic acid residue, cyclopent Tantetracarboxylic acid residue, dicyclohexane-3,4,3',4'-tetracarboxylic acid A group consisting of residues and 4,4'-(hexafluoroisopropylidene)diphthalic acid residues. At least one tetravalent group selected from, R 6 This represents a divalent group, which is a diamine residue. n' represents the number of repeating units and is 1 or greater.

[0062] In the above general formula (1), R 1 is a tetracarboxylic acid residue, as exemplified above. The residue obtained by removing the acid dianhydride structure from the tetracarboxylic dianhydride is as follows. R in general formula (1) 1 In particular, it improves 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'-bi A phenyltetracarboxylic acid residue, 3,3',4,4'-benzophenonetetracarboxylic acid residue, a 3,3',4,4'-diphenylsulfonetetracarboxylic acid residue, 4,4'-oxy diphthalic acid residue, a cyclohexanetetracarboxylic acid residue, and a cyclopentanetetrac arboxylic acid residue, and preferably contains at least one selected from the group consisting of a 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, a 4,4'-oxydiph thalic acid residue, and a 3,3',4,4'-diphenylsulfonetetracarboxylic acid residue selected from the group consisting of.

[0063] R 1 Preferably, these preferred residues are contained in a total amount of 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more.

[0064] Also, as R 1 a tetracarboxylic acid residue group (Group A) suitable for improving rigidity, such as at least one selected from the group consisting of a 3,3',4,4'-biphenyltetracarboxylic acid residue, 3,3' ,4,4'-benzophenonetetracarboxylic acid residue, and a pyromellitic acid residue and a tetracarboxylic acid residue group (Group B) suitable for improving transparency, such as at least one selected from the group consisting of a 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, a 2,3',3,4'-biphenyltetracarboxylic acid residue, a 3,3',4,4'-dip henylsulfonetetracarboxylic acid residue, a 4,4'-oxydiphthalic acid residue, a cyclohexane tetracarboxylic acid residue, and a cyclopentanetetracarboxylic acid residue, are preferably mixed and used. Group B) are preferably mixed and used. It is also preferable to use a mixture of a group of tetracarboxylic acid residues (Group B) suitable for improving transparency, such as at least one selected from the group consisting of a 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, a 2,3',3,4'-biphenyltetracarboxylic acid residue, a 3,3',4,4'-diphenylsulfonetetracarboxylic acid residue, a 4,4'-oxydiphthalic acid residue, a cyclohexanetetracarboxylic acid residue, and a cyclopentanetetracarboxylic acid residue. ​

[0065] In this case, the group of tetracarboxylic acid residues (group A) suitable for improving the rigidity and The content ratio of tetracarboxylic acid residues (group B) suitable for improving transparency is, For 1 mole of tetracarboxylic acid residues (group B) suitable for improving transparency, the following The tetracarboxylic acid residue group (Group A) suitable for improving rigidity is present in 0.05 moles or less. Preferably, the amount is 9 moles or less, and more preferably 0.1 moles or more and 5 moles or less. Furthermore, it is preferable that the amount is between 0.3 moles and 4 moles.

[0066] In the above general formula (1), R 2 In particular, improving light transmittance and rigidity From this point of view, the 4,4'-diaminodiphenylsulfone residue, 3,4'-diaminodiphenyl A small number of sulfone residues and divalent groups selected from the group consisting of the above general formula (2) Preferably, it is at least one type of divalent group, and further, 4,4'-diaminodiphenyl Lufon residue, 3,4'-diaminodiphenylsulfone residue, and R 3 and R 4 but Select from the group consisting of divalent groups represented by the above general formula (2), which are perfluoroalkyl groups. It is preferable that it be at least one divalent group.

[0067] In the above general formula (3), R 5 In particular, improving light transmittance and rigidity. From this point of view, the 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 3,3' Contains ,4,4'-diphenylsulfonetetracarboxylic acid residues and oxydiphthalic acid residues. It is preferable to do so.

[0068] R5 In this, it is preferable that these preferred residues are present in an amount of 50 mol% or more, and more preferably 70 It is preferable that it contains 90 mol% or more, and more preferably 90 mol% or more.

[0069] In the above general formula (3), R 6 is a diamine residue, and is a diamine as exemplified above. It can be a residue obtained by removing two amino groups from the above general formula (3). 6 and In particular, in terms of improving light transmittance and rigidity, 2,2'-screw (tri Fluoromethyl)benzidine residue, bis[4-(4-aminophenoxy)phenyl]sulfate Hon residue, 4,4'-diaminodiphenylsulfone residue, 2,2-bis[4-(4-ami [( [Xy)phenyl]sulfone residue, 4,4'-diamino-2,2'-bis(trifluoromethyl) (Tyl)diphenyl ether residue, 1,4-bis[4-amino-2-(trifluoromethyl )phenoxy]benzene residue, 2,2-bis[4-(4-amino-2-trifluoromethyl [Phenoxy)phenyl]hexafluoropropane residue, 4,4'-diamino-2-( (Lifluoromethyl)diphenyl ether residue, 4,4'-diaminobenzanilide residue, N,N'-bis(4-aminophenyl)terephthalamide residues, and 9,9-bis(4- It contains at least one divalent group selected from the group consisting of aminophenyl)fluorene residues. It is preferable to include a 2,2'-bis(trifluoromethyl)benzidine residue, bis [4-(4-aminophenoxy)phenyl]sulfone residues and 4,4'-diaminodiph It is preferable to include at least one divalent group selected from the group consisting of phenylsulfone residues. It's nice.

[0070] R 6 In this, it is preferable that these preferred residues total 50 mol% or more, and further It is preferable that it contains 70 mol% or more, and more preferably 90 mol% or more.

[0071] Also, R 6 As such, bis[4-(4-aminophenoxy)phenyl]sulfone residue, 4 ,4'-diaminobenzanilide residue, N,N'-bis(4-aminophenyl)terephthalate Luamide residue, paraphenylenediamine residue, metaphenylenediamine residue, and 4, At least one selected from the group consisting of 4'-diaminodiphenylmethane residues. A group of diamine residues (Group C) suitable for improving rigidity, and 2,2'-bis(truffle) Luoromethyl)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 residues, and 9,9-bis( At least one selected from the group consisting of 4-aminophenyl)fluorene residues. It is also preferable to use a mixture with a group of diamine residues (group D) that are suitable for improving transparency. It seems so.

[0072] In this case, the diamine residue group (group C) suitable for improving the rigidity, and transparency The ratio of diamine residues (group D) suitable for improving transparency is For 1 mole of a group of diamine residues (group D) suitable for improving the rigidity, It is preferable that the group of diamine residues (group C) is between 0.05 moles and 9 moles. Furthermore, it is preferable that the amount is between 0.1 moles and 5 moles, and between 0.3 moles and 4 moles. It is preferable to do so.

[0073] In the structures represented by the above general formulas (1) and (3), n and n' are Each represents the number of repeating units, and is 1 or greater. Repeating units in polyimide The number n is appropriately selected according to the structure so as to show a preferred glass transition temperature, as described later. Generally, it is not limited to this. The average number of repeating units is usually 10 to 2000, and furthermore 15 It is preferable that it be ~1000.

[0074] Furthermore, polyimide resins may contain a polyamide structure as part of their composition. Examples of polyamide structures that may be used include tricarbons such as trimellitic anhydride. Polyamide-imide structures containing acid residues, and polyamide-imide structures containing dicarboxylic acid residues such as terephthalic acid. A riamid structure is one example.

[0075] Polyimide resins are preferable to have a glass transition temperature of 250°C or higher in terms of heat resistance. Furthermore, it is preferable that the temperature is 270°C or higher. On the other hand, ease of stretching and low bake temperature From the perspective of reduction, it is preferable that the glass transition temperature is 400°C or lower, and more preferably 380°C or lower. It is preferable that this be the case.

[0076] Specifically, examples of the polyimide resin include compounds having a structure represented by the following formula Among them. In the following formula, n is a repeating unit and represents an integer of 2 or more.

Chemical formula

[0077]

Chemical formula

[0078]

Chemical formula

[0079]

Chemical formula

[0080]

Chemical formula

[0081]

Chemical formula

[0086]

Chem.

[0087]

Chem.

[0088]

Chem.

[0089]

Chem.

[0090]

Chem.

[0091]

Chem.

[0092]

Chem.

[0093] Polyamide resins include not only aliphatic polyamides but also aromatic polyamides (aramids). [[ID=​​​​​​​​​​​​​​

[0095] [ka]

[0096] [ka]

[0097] Polyimide resin or polyamide resin represented by the above formulas (4) to (20) and (23) A commercially available base material consisting of fat may be used. Examples of such products include NeoPrim manufactured by Mitsubishi Gas Chemical Company, and the above-mentioned aramid resin or Examples of commercially available base materials include Toray Industries' Miktron.

[0098] Furthermore, polyimide resin or polya represented by the above formulas (4) to (20) and (23) The mid resin may be one synthesized by known methods. For example, the above formula (4) is shown The method for synthesizing the polyimide resin is described in Japanese Patent Application Publication No. 2009-132091, and Physically, it is 4,4'-hexafluoropropylene bisphthalate, represented by the following formula (24). Acid dianhydride (FPA) and 2,2'-bis(trifluoromethyl)-4,4'-diaminobi It can be obtained by reacting it with phenyl (TFDB). [ka]

[0099] The weight-average molecular weight of the above polyimide resin or polyamide resin is 3,000 or more and 500,000 or less. It is preferable that it be in the range below, and more preferably in the range of 5,000 to 300,000, It is even more preferable that the weight-average molecular weight is in the range of 10,000 to 200,000. If this occurs, sufficient strength may not be obtained, and if it exceeds 500,000, viscosity increases and solubility decreases. Therefore, a substrate with a smooth surface and uniform film thickness may not be obtained. In this context, "weight-average molecular weight" is measured by gel permeation chromatography (GPC). This is a polystyrene equivalent value.

[0100] Among the above polyimide resins and polyamide resins, it has excellent transparency. , polyimide resins or aramids having a structure in which intramolecular or intermolecular charge transfer is less likely to occur. A resin is preferred, specifically a fluorinated polyimide resin such as those of formulas (4) to (11) above. Polyimide resins having alicyclic structures such as those in formulas (13) to (15) above, and ha Examples include polyamide resins having rogenic groups.

[0101] Furthermore, in fluorinated polyimide resins such as those in formulas (4) to (11) above, the fluorinated structure Because it has high heat resistance, it can withstand the heat generated during the manufacturing of the base material made of polyimide resin. Since it is not colored, it has excellent transparency.

[0102] The resin substrate 11 is made of materials that can improve hardness, such as those specified in formulas (4) to (11) above. A fluorinated polyimide resin represented by the above formula (23) or an aramic resin having a halogen group such as the above formula (23) It is preferable to use a base material made of resin. In particular, it is preferable to use a base material that can further improve hardness. From the viewpoint of being able to do so, using a substrate made of polyimide resin represented by the above formula (4) is more preferable.

[0103] Examples of polyester resins include polyethylene terephthalate and polypropylene terephthalate. at least one of refthalate, polybutylene terephthalate, or polyethylene naphthalate Examples include resins that contain seeds as a component.

[0104] <<Hard coat layer>> The hard coat layer 12 has a Martens hardness of 37 at the center of the cross-section of the hard coat layer 12. This refers to layers with a hardness of 5 MPa or higher. In this specification, "Martens hardness" means Hardness measurement using nanoindentation method: Hardness when the indenter is pressed in 500 nm. The above measurement of Martens hardness by nanoindentation method is performed at HYSITRO. The procedure is performed using the "TI950 TriboIndenter" manufactured by N (Hygitron). This shall be the case. That is, under the following measurement conditions, the indenter shall be a Berkovich indenter (triangular A drill bit is pressed 500 nm into the center of the cross-section of the hard coat layer and held for a certain period of time to relieve residual stress. After the load is removed, the maximum load after relaxation is measured, and the maximum load P is measured. max (μN) and Area A of depression with a depth of 500 nm (nm) 2 ) and P max / A causes Martens hardness The degree is calculated. The Martens hardness is the arithmetic mean of the values ​​obtained from measurements at 10 locations. (Measurement conditions) ·Loading speed: 10nm / sec ·Holding time: 5 seconds ·Loading and unloading speed: 10nm / sec ·Measurement temperature: 25℃

[0105] The thickness of the hard coat layer 12 is preferably 1 μm or more and 20 μm or less. If the thickness of the hard coat layer 12 is less than 1 μm, the hardness of the hard coat layer will decrease. Furthermore, if the thickness exceeds 20 μm, the processability deteriorates due to the excessive thickness. There is a risk of this happening. In this specification, "thickness of the hard coat layer" refers to a hard coat layer that is multilayered. In the case of a structure, it refers to the total thickness, which is the sum of the thicknesses of each hard coat layer. The upper limit of the hard coat layer 12 is more preferably 15 μm or less. It is even more preferable that the size be μm or smaller.

[0106] The thickness of the hard coat layer was measured using a scanning electron microscope (SEM) to cross-section the hard coat layer. The surface was photographed, and the thickness of the hard coat layer was measured at 20 locations in the cross-sectional image. The arithmetic mean of the film thickness at each location is used. The specific method for taking cross-sectional photographs is described below. First, A block was created by embedding optical film cut to 1mm x 10mm in embedding resin. Then, using a general sectioning method, uniform sections free of holes, etc., with a thickness of 70 nm or less are obtained from this block. Sections of 100 nm or less are cut out. Sections are prepared using an "Ultramicrotome EM". You can use the UC7 (Leica Microsystems Inc.), etc. The remaining block from which uniform sections free of holes, etc., have been cut is used as the measurement sample. Then, Scanning electron microscope (SEM) (product name "S-4800", Hitachi High-Technologies Corporation) Using a (manufactured by Z Corporation), a cross-sectional photograph of the measurement sample is taken. Using the above S-4800, the cross-section When taking a photograph, set the detector to "SE", the acceleration voltage to "5kV", and the emission current to Perform cross-sectional observation with a "10μA" setting. Adjust the focus and contrast to control the magnification. Then, adjust the brightness appropriately between 100 and 100,000 times while observing whether each layer can be distinguished. Oh, when taking cross-sectional photos using the S-4800 mentioned above, you should also set the aperture to "B Set the monitor aperture to "3", the objective lens aperture to "3", and the WD to "8mm". This may also be done. When measuring the thickness of the first layer, when observing the cross-section, the hard coat layer and other layers may be observed. It is important that the interface contrast with (for example, a resin substrate) can be observed as clearly as possible. Yes. If, for example, this interface is difficult to see due to insufficient contrast, osmium tetroxide, tetraacid Applying staining treatments such as ruthenium chloride or phosphotungstic acid makes the interfaces between organic layers more visible. Therefore, staining treatment may be performed. Also, the contrast of the interface is more clearly visible at higher magnifications. It can be difficult in some cases. In such cases, observe at a lower magnification simultaneously. For example, 25,000x and 50,000x. Observe at two magnifications, such as double or 50,000x and 100,000x, and calculate the arithmetic mean of both magnifications as described above. We calculate this value, and then use its average value as the thickness of the hard coat layer.

[0107] The hard coat layer may be a single layer, but a two-layer structure is recommended to improve folding performance. The above multilayer structure is preferable. In Figure 1, the hard coat layer 12 is the first hard Coat layer 12B and second hard coat layer 1 laminated on the first hard coat layer 12B An example consisting of 2C is shown.

[0108] <First hard coat layer> The first hard coat layer 12B is primarily a layer for imparting hardness to the optical film. The first hard coat layer 12B has a malte in the center of the cross-section of the first hard coat layer 12B. A hardness of 500 MPa or more and 2000 MPa or less is preferable. If the pressure is too high, the hardness of the hard coat layer may be insufficient, exceeding 2000 MPa. This can result in insufficient folding performance of the optical film. First hard coat layer 12 The lower limit of the Martens hardness at the center of the cross-section of B is preferably 600 MPa or higher. The upper limit is preferably 1500 MPa or less.

[0109] The Martens hardness of the first hard coat layer 12B is equal to the Martens hardness of the second hard coat layer 12C. It is preferable that the hardness is greater than that of Martens. As a result, the optical film 10 exhibits particularly good pencil hardness. This is because the optical film 10 has a pencil hardness. When a hardness test was performed and a load was applied to the pencil and pressed down, the deformation of the optical film 10 was suppressed. This reduces scratches, dents, and deformation. The first hard coat layer 12B is made of martensite. One way to make the hardness greater than the Martens hardness of the second hard coat layer 12C is, For example, the inorganic particle content described later is more abundant on the first hard coat layer 12B side. Methods for controlling it include the following. Furthermore, if the hard coat layer has a single-layer structure, The inorganic particles in the coating layer are unevenly distributed towards the substrate film side, that is, the hard coat layer The proportion of inorganic particles is higher on the resin substrate side and higher towards the surface side of the optical film. Therefore, it is preferable that the slope is such that it becomes smaller.

[0110] The first hard coat layer 12B contains resin. Preferably, the resin further contains inorganic particles dispersed within it.

[0111] (resin) The resin contains polymers (cured products) of polymerizable compounds (curable compounds). Polymerizable compounds are It has at least one polymerizable functional group within the molecule. Examples of polymerizable functional groups include Examples include ethylenically unsaturated groups such as (meth)acryloyl groups, vinyl groups, and allyl groups. Note that "(meth)acryloyl group" refers to both "acryloyl group" and "methacryloyl group". It has a meaning that includes both "base" and "foundation".

[0112] As polymerizable compounds, polyfunctional (meth)acrylates are preferred. Examples of acrylates include trimethylolpropane tri(meth)acrylate, Repropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate Relate, dipropylene glycol di(meth)acrylate, pentaerythritol triphosphate (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentae Lythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate Rate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri (meth)acrylate, ditrimethylolpropanetetra(meth)acrylate, dipene Taerythritol penta(meth)acrylate, tripentaerythritol octa(meth)acrylate )Acrylate, tetrapentaerythritol dec(meth)acrylate, isocyanuryl Acid tri(meth)acrylate, isocyanuric acid di(meth)acrylate, polyester Polyester(meth)acrylate, polyester(meth)acrylate, bisphenol(meth)acrylate Acrylate, diglycerin tetra(meth)acrylate, adamantyl di(meth) Acrylate, isoboronyl di(meth)acrylate, dicyclopentane di(meth)acrylate Relate, Tricyclodecanedi(meth)acrylate, Ditrimethylolpropanetetra Examples include (meth)acrylates and those modified with PO, EO, caprolactone, etc. It is possible.

[0113] Among these, those that can suitably satisfy the aforementioned Martens hardness are suitable for 3-6 functional groups. It is preferable to use, for example, pentaerythritol triacrylate (PETA), dipenta Erythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate PETTA, dipentaerythritol pentaacrylate (DPPA), trim Tyrolpropane tri(meth)acrylate, tripentaerythritol octa(meth) Acrylates, tetrapentaerythritol dec(meth)acrylate, etc. are preferred. In this specification, (meth)acrylate means acrylate and methacrylate. It means.

[0114] Furthermore, to adjust hardness, viscosity of the composition, and improve adhesion, monofunctional (meth)acrylic is used. It may also contain rate monomers. The above monofunctional (meth)acrylate monomers are For example, hydroxyethyl acrylate (HEA), glycidyl methacrylate, metho Xypolyethylene glycol (meth)acrylate, isostearyl (meth)acrylate T, 2-acryloyloxyethyl succinate, acryloylmorpholine, N-acryloyl Royloxyethylhexahydrophthalimide, cyclohexyl acrylate, tetrahydroxy Drolphryl acrylate, isobornyl acrylate, phenoxyethyl acrylate, Other examples include adamantyl acrylate.

[0115] The weight-average molecular weight of the above monomer is less than 1000, from the viewpoint of improving the hardness of the resin layer. The weight of the polymerizable oligomer is also specified. The average molecular weight is preferably between 1,000 and 20,000, and preferably between 1,000 and 10,000. It is more preferable that the value be between 2000 and 7000.

[0116] (Inorganic particles) As for inorganic particles, there are no particular limitations as long as hardness can be improved, but excellent hardness From the viewpoint of obtaining the desired degree, silica particles are preferred. Among silica particles, reactive silica particles are preferred. The above reactive silica particles form a crosslinked structure with the above polyfunctional (meth)acrylate. These are silica particles that can be formed, and by containing these reactive silica particles, the first The hardness of the hard coat layer 12B can be sufficiently increased.

[0117] The above-mentioned reactive silica particles preferably have reactive functional groups on their surface, and As for the functional group, for example, the polymerizable functional group described above is preferably used.

[0118] The above-mentioned reactive silica particles are not particularly limited and conventionally known particles can be used. For example, reactive silica particles as described in Japanese Patent Publication No. 2008-165040 can be cited. Furthermore, commercially available reactive silica particles include, for example, MIBK-S manufactured by Nissan Chemical Industries, Ltd. D, MIBK-SDMS, MIBK-SDL, MIBK-SDZL, manufactured by JGC Catalysts & Chemicals Co., Ltd. Examples include the V8802 and V8803.

[0119] Furthermore, the above silica particles may be spherical silica particles, but may also be irregularly shaped silica particles. This is preferable. Spherical silica particles and irregularly shaped silica particles may be mixed. In this context, "spherical silica particles" refers to silica particles that are, for example, perfectly spherical or ellipsoidal. Furthermore, "irregularly shaped silica particles" refer to potato-shaped particles (with an aspect ratio of 1.2 or higher when observed in cross-section). This refers to silica particles with a surface shape having random irregularities (40 or less). Because the surface area of ​​these particles is larger compared to spherical silica particles, these irregularly shaped silica particles By containing the above-mentioned polyfunctional (meth)acrylate, the contact area with the above-mentioned polyfunctional (meth)acrylate increases, The hardness of the hard coat layer can be improved. The silicon contained in the hard coat layer Whether or not the particles are heteromorphic silica particles can be determined by examining a cross-section of the hard coat layer using a transmission electron microscope (T This can be confirmed by observation with an EM (electromagnetic pulse) or scanning transmission electron microscope (STEM). can.

[0120] The average particle size of the above silica particles is preferably between 5 nm and 200 nm. If the particle size is less than nm, it becomes difficult to manufacture the particle itself, and the particles may aggregate with each other. Furthermore, it can become extremely difficult to create irregular shapes, and also, at the ink stage before coating as described above... Therefore, the dispersibility of irregularly shaped silica particles is poor and they may aggregate. On the other hand, the above irregularly shaped silica particles When the average particle size exceeds 200 nm, large irregularities are formed in the hard coat layer, and Problems such as an increase in noise may occur. Silica particles are in the field of spherical silica particles. In this case, the average particle size of silica particles is measured using a transmission electron microscope (TEM) or scanning transmission electron microscope. The particle size of 20 particles was measured from cross-sectional images of particles taken using a microscope (STEM). The arithmetic mean of the particle sizes of the 20 particles is used. Also, if the silica particles are irregularly shaped silica particles In such cases, the average particle size of silica particles is measured using a transmission electron microscope (TEM) or scanning transmission electron microscope. From images of the cross-section of the hard coat layer taken using an electron microscope (STEM), the outer circumference of the particles can be determined. The maximum (major axis) and minimum (minor axis) distances between two points are measured, and the particle size is calculated by averaging them. This is the arithmetic mean of the particle diameters of each individual particle.

[0121] By controlling the size and amount of the inorganic particles mentioned above, the hardness of the first hard coat layer 12B can be controlled. (Martens hardness) can be controlled. For example, when forming the first hard coat layer 12B. The above silica particles have a diameter of 5 nm to 200 nm, and the above polymerizable compound 100% It is preferable that the amount is 25 to 60 parts by mass relative to the total volume.

[0122] <Second hard court layer> The second hard coat layer 12C is a layer that satisfies the continuous folding test described above. The second hard coat layer 12C has a cross-section at the center of the second hard coat layer 12C. The Lutens hardness is preferably between 375 MPa and 1500 MPa. If the value is less than 'a', the scratch resistance of the hard coat layer may be insufficient, and 1500 MPa Beyond a certain point, the folding resistance of the optical film becomes insufficient, and the continuous folding test described above fails. This may not be satisfied. Martens in the center of the cross-section of the second hard coat layer 12C The lower limit of hardness is more preferably 450 MPa or higher, and the upper limit is 575 MPa or lower. It is preferable to do so.

[0123] The second hard coat layer 12C contains resin. The resin may further contain inorganic particles dispersed within it.

[0124] (resin) The resin contains polymers (cured products) of polymerizable compounds (curable compounds). In this case, polyfunctional (meth)acrylates are preferred. Examples include the polyfunctional (meth)acrylates listed in the column for the first hard coat layer 12B. In addition, the second hard coat layer 12C contains the above-mentioned polyfunctional (meth)acrylate. Therefore, polyfunctional urethane (meth)acrylate and / or polyfunctional epoxy (meth)acrylate It may include things like "t".

[0125] (Inorganic particles) Examples of inorganic particles include those similar to those listed in the section for the first hard coat layer 12B. The inorganic particle content in the second hard coat layer 12C is not particularly limited. However, it is preferable that the amount is, for example, 0 to 50% by mass relative to the second hard coat layer 12C. .

[0126] At least one of the first hard coat layer 12B and the second hard coat layer 12C This applies even if it contains materials other than those mentioned above, as long as it satisfies the aforementioned Martens hardness. Often, for example, polymerizable materials that form a cured product upon irradiation with ionizing radiation are used as resin components. It may contain monomers or polymerizable oligomers, etc. The above polymerizable monomer or polymerizable oligomer Examples of somers include (meth)acrylates that have radically polymerizable unsaturated groups in their molecules. (Meth)acrylate monomers, or (meth)acrylate monomers having radically polymerizable unsaturated groups in the molecule. Gomer is an example. (Meth)acrylate having a radically polymerizable unsaturated group in the above molecule. (Meth)acrylate monomers, or (meth)acrylate monomers having radically polymerizable unsaturated groups in the molecule. Examples of gommers include urethane (meth)acrylate and polyester (meth)acrylate. Rate, epoxy (meth)acrylate, melamine (meth)acrylate, polyfluoro monomers or oligonucleotides such as alkyl (meth)acrylates and silicone (meth)acrylates. Examples include sesame oils. These polymerizable monomers or polymerizable oligomers may be one or more types. These may be used in combination. In particular, polyfunctional (6 or more functional) with a weight-average molecular weight of 1 A urethane (meth)acrylate with a value of 000 to 10,000 is preferred.

[0127] Hard coat layer 12 (first hard coat layer 12B and second hard coat layer 12C) At least one of the following is an ultraviolet absorber, a spectral transmittance modifier, and / or an antifouling agent. It may also contain additional content.

[0128] <UV absorber> Optical films are used in mobile devices such as foldable smartphones and tablets. It is particularly suitable for use at the end, but such mobile devices are often used outdoors. Therefore, the polarizer, which is positioned on the display element side of the optical film, is exposed to ultraviolet light and deteriorates. There is a problem with this. However, the resin layer is placed on the display screen side of the polarizer. Furthermore, if the resin layer contains an ultraviolet absorber, the polarizer will deteriorate when exposed to ultraviolet light. This can effectively prevent the above ultraviolet absorber (UVA) from the resin substrate 11. and / or may be contained in the resin layer 13. In this case, the ultraviolet absorber (UVA) is It does not need to be contained in the hard coat layer 12.

[0129] Examples of UV absorbers include triazine-based UV absorbers and benzophenone-based UV absorbers. Examples include absorbents and benzotriazole-based ultraviolet absorbers.

[0130] Examples of the above triazine-based UV absorbers include 2-(2-hydroxy-4-[1- Octyloxycarbonylethoxyphenyl)-4,6-bis(4-phenylphenyl) )-1,3,5-triazine, 2-[4-[(2-hydroxy-3-dodecyloxypro [Pyroxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl) )-1,3,5-triazine, 2,4-bis[2-hydroxy-4-butoxyphenyl] -6-(2,4-dibutoxyphenyl)-1,3,5-triazine, 2-[4-[(2- Hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4 ,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, and 2-[4- [(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphen Examples include [L]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine. Examples of commercially available triazine-based UV absorbers include TINUVIN46. 0, TINUVIN477 (both manufactured by BASF), LA-46 (manufactured by ADEKA) These are some examples.

[0131] Examples of the above-mentioned benzophenone-based UV absorbers include 2-hydroxybenzophenone. , 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethyl Cibenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-hydro Xy-4-methoxybenzophenone, hydroxymethoxybenzophenone sulfonic acid and Examples include its trihydrate and sodium hydroxymethoxybenzophenone sulfonate. Examples of commercially available benzophenone-based UV absorbers include CHMASSORB8. Examples include the 1 / FL (manufactured by BASF).

[0132] Examples of the above-mentioned benzotriazole-based UV absorbers include 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole] 2-(2H-benzotriazol-2-yl)phenyl]propionate, 2-(2H-benzotriazol-2-yl) )-6-(linear and side-chain dodecyl)-4-methylphenol, 2-[5-chloro(2H) -benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol , 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylfe Nol, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-( 2'-Hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotri Azole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5 -Chlorobenzotriazole, 2-(2'-Hydroxy-3'-(3'',4'',5' ',6''-tetrahydrophthalimidomethyl)-5'-methylphenyl)benzotri Zole, 2,2-methylenebis(4-(1,1,3,3-tetramethylbutyl)-6-( 2H-benzotriazole-2-yl)phenol, and 2-(2'-hydroxy- 3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole, etc. Examples include commercially available benzotriazole-based UV absorbers, such as KE MISORB71D, KEMISORB79 (both manufactured by Chemipro Chemical Co., Ltd.), JF-8 0, JAST-500 (both manufactured by Johoku Chemical Co., Ltd.), ULS-1933D (manufactured by Ippo Co., Ltd.), Examples include RUVA-93 (manufactured by Otsuka Chemical Co., Ltd.).

[0133] Among UV absorbers, triazine-based UV absorbers and benzotriazole-based UV absorbers are particularly noteworthy. An absorbent is preferably used. The ultraviolet absorber is dissolved in the resin component that makes up the hard coat layer. Higher resolvability is preferable, and less bleed-out after the continuous folding test described above. It is preferable that the UV absorber is polymerized or oligomerized. It is difficult. As UV absorbers, benzotriazole, triazine, and benzophenone skeletons are used. The polymer or oligomer containing it is preferred, specifically benzotriazole or benzof A (meth)acrylate having an enone skeleton and methyl methacrylate (MMA) are optionally It is preferable that the material is thermally copolymerized in the ratio of [specific ratio]. Furthermore, organic light-emitting diodes (OLEDs) are used. When applying an optical film to a display device, UV absorbers protect the OLED from ultraviolet light. It can also fulfill that role.

[0134] The amount of UV absorber is not particularly limited, but the solid content of the hard coat layer composition Preferably, the amount is 1 part by mass or more and 6 parts by mass or less per 100 parts by mass. If present, the effect of incorporating the aforementioned UV absorber into the hard coat layer can be fully obtained. In some cases, this may not be possible, and if the amount exceeds 6 parts by mass, significant discoloration or a decrease in strength may occur in the hard coat layer. This may occur. The more preferable lower limit for the content of the above ultraviolet absorber is 2 parts by mass or more, more preferably The maximum limit is 5 parts by mass or less.

[0135] <Spectral transmittance modifier> Spectral transmittance adjusting agents are used to adjust the spectral transmittance of optical films. (Hard coat) Layer 12 contains, for example, a sesamol-type benzotriazole compound represented by the following general formula (25). When a mer is included, the spectral transmittance described above can be suitably satisfied. [ka] In the formula, R 7 R represents a hydrogen atom or a methyl group. 8 It is a linear or branched chain with 1 to 6 carbon atoms. A linear alkylene group or a linear or branched oxyalkylene group having 1 to 6 carbon atoms is represented. vinegar.

[0136] The above sesamol-type benzotriazole monomers are not particularly limited, but specific The substance name is 2-[2-(6-hydroxybenzo[1,3]dioxol-5-I (Lu)-2H-benzotriazol-5-yl]ethyl methacrylate, 2-[2-(6- Hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole-5 -yl]ethyl acrylate, 3-[2-(6-hydroxybenzo[1,3]dioxose Lu-5-yl)-2H-benzotriazol-5-yl]propyl methacrylate, 3- [2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotri Azole-5-yl]propyl acrylate, 4-[2-(6-hydroxybenzo[1, 3]Dioxol-5-yl)-2H-benzotriazole-5-yl]butylmethacrylate Rate, 4-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H -benzotriazol-5-yl]butylacrylate, 2-[2-(6-hydroxybe Nzo[1,3]dioxol-5-yl)-2H-benzotriazole-5-yloxy ]Ethyl methacrylate, 2-[2-(6-hydroxybenzo[1,3]dioxol- 5-yl)-2H-benzotriazole-5-yloxy]ethyl acrylate, 2-[ 3-{2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzo Triazole-5-yl}propanoyloxy]ethyl methacrylate, 2-[3-{2- (6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole [Lu-5-yl]propanoyloxy]ethyl acrylate, 4-[3-{2-(6-hydro Xybenzo[1,3]dioxol-5-yl)-2H-benzotriazole-5-yl }propanoyloxy]butyl methacrylate, 4-[3-{2-(6-hydroxyben Zo[1,3]dioxol-5-yl)-2H-benzotriazole-5-yl}prop [Noyloxy]butyl acrylate, 2-[3-{2-(6-hydroxybenzo[1,3 ]Dioxol-5-yl)-2H-benzotriazole-5-yl}propanoyl oxy [C]ethyl methacrylate, 2-[3-{2-(6-hydroxybenzo[1,3]dioxy Sole-5-yl)-2H-benzotriazole-5-yl}propanoyloxy]eth 1 acrylate, 2-(methacryloyloxy)ethyl 2-(6-hydroxybenzo[1 ,3]Dioxol-5-yl)-2H-benzotriazole-5carboxylate, 2 -(acryloyloxy)ethyl 2-(6-hydroxybenzo[1,3]dioxol- 5-yl)-2H-benzotriazole-5-carboxylate, 4-(methacryloyl) Oxy)butyl 2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H -benzotriazole-5-carboxylate, 4-(acryloyloxy)butyl 2- (6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole Examples include ru-5-carboxylate. Also, these sesamol-type benzoates One type of riazole monomer may be used, or two or more types may be used.

[0137] The above sesamol-type benzotriazole monomer may also be contained in the resin layer 13. However, if the resin layer has a multilayer structure of two or more layers, the above components are contained in one or more resin layers. The requirements for light transmittance may also be met. For example, one of the resin layers may be spectrally analyzed at a wavelength of 380 nm. The above sesamol-type benzotriazole monomer is included to achieve only the transmittance, The spectral transmittance conditions at wavelengths of 410 nm and 440 nm can be achieved with other resin layers. Examples of configurations include those containing the above-mentioned sesamol-type benzotriazole monomer. Furthermore, the resin layer consists of three or more layers, and each resin layer satisfies the aforementioned spectral transmittance requirements. The above-mentioned sesamol-type benzotriazole monomer may also be included.

[0138] When the above sesamol-type benzotriazole monomer is contained in the resin layer 13, for example, For example, the above sesamol-type benzotriazole monomer is present in 15 to 30 masses per 13 resin layers. It is preferable that it be contained in %. Sesamol-type benzotriazole within this range. The presence of the monomer system allows the above-mentioned spectral transmittance to be satisfied. The sesamol-type benzotriazole monomer constitutes the resin layer 13. The resin components may react with and be integrally contained with the resin components that constitute the resin layer 13. It may be included alone without reacting with anything else.

[0139] <Anti-fouling agent> The antifouling agent may be uniformly dispersed in the hard coat layer, but even with a small amount added... From the perspective of obtaining sufficient stain resistance and suppressing the reduction in the strength of the hard coat layer, It is preferable that it is unevenly distributed on the surface side of the hard coat layer. In this context, a method for unevenly distributing the antifouling agent to the surface side of the hard coat layer is, for example, hard When forming the coating layer, the coating film formed using the hard coat layer composition is dried. Before curing, the coating is heated to reduce the viscosity of the resin components contained in the coating, thus improving its flow. Methods to increase mobility and cause the antifouling agent to be unevenly distributed on the surface side of the hard coat layer, or methods for preventing low surface tension Select and use a stain-resistant agent, and without applying heat during the drying of the coating, allow the stain-resistant agent to float on the surface of the coating, and then... Methods such as hardening the coating film to concentrate the above-mentioned antifouling agent on the outermost surface of the hard coat layer are available. These can be listed. Also, in the case of a hard coat layer with a multilayer structure, such as hard coat layer 12, By incorporating an antifouling agent into the hard coat layer on the surface side, the surface side of the hard coat layer is protected It is possible to distribute the contaminant unevenly.

[0140] The antifouling agent is not particularly limited; for example, silicone-based antifouling agents, fluorine-based antifouling agents, silicone Examples include cone-type and fluorine-based antifouling agents, which can be used individually or mixed together. It is also permissible to use an acrylic-based antifouling agent.

[0141] The antifouling agent content is 0.01 to 3.0 parts by mass of the resin component mentioned above. It is preferable that it be parts by mass. If it is less than 0.01 parts by mass, the resin layer will not have sufficient antifouling performance. It may not be possible to impart it, and if it exceeds 3.0 parts by mass, the hardness of the hard coat layer will decrease. There is a risk that this may happen.

[0142] The antifouling agent preferably has a weight-average molecular weight of 5000 or less, and the durability of the antifouling performance is To improve the compound, preferably has one or more reactive functional groups, more preferably two or more. In particular, by using an antifouling agent having two or more reactive functional groups, excellent resistance It can impart abrasion resistance.

[0143] If the antifouling agent does not have reactive functional groups, even if the optical film is in roll form, it will be in sheet form. Even in that case, when stacked, the antifouling agent is transferred to the back of the optical film, and the optical film If you try to attach or apply another layer to the back of this, the other layer may peel off. Furthermore, it may peel off easily after multiple consecutive folding tests.

[0144] Furthermore, the antifouling agent having the above-mentioned reactive functional group exhibits good performance retention (durability) of its antifouling properties. In particular, the hard coat layer containing the aforementioned fluorine-based antifouling agent is less prone to fingerprints. It is inconspicuous, and easy to wipe off. Furthermore, the surface of the hard coat layer composition during application. Because surface tension can be reduced, leveling properties are improved, and the appearance of the formed hard coat layer is enhanced. This will be a good result.

[0145] The hard coat layer containing a silicone-based antifouling agent has good slipperiness and good resistance to steel wool. This is good. The hard coat layer is equipped with an optical film containing such a silicone-based antifouling agent. The touch sensor improves tactile sensation because it allows for smoother gliding when touched with a finger or pen. Furthermore, fingerprints are less likely to stick to (or be noticeable) on the hard coat layer, and it is easy to wipe clean. Furthermore, it is possible to lower the surface tension of the hard coat layer composition during application, thus leveling up It has good coating properties and produces a good-looking hard coat layer.

[0146] Examples of commercially available silicone-based antifouling agents include SUA1900L10 (Shin Nakamura Chemical Co., Ltd.). (Manufactured by), SUA1900L6 (manufactured by Shin Nakamura Chemical Co., Ltd.), Ebecryl1360 (manufactured by Daicel Corporation) (Manufactured by Tech Co., Ltd.), UT3971 (Manufactured by Nippon Gosei Co., Ltd.), BYKUV3500 (Manufactured by Big Chemie Co., Ltd.) ), BYKUV3510 (manufactured by Bic Chemie), BYKUV3570 (manufactured by Bic Chemie) ), X22-164E, X22-174BX, X22-2426, KBM503, KBM 5103 (manufactured by Shin-Etsu Chemical Co., Ltd.), TEGO-RAD2250, TEGO-RAD2300, T EGO-RAD2200N, TEGO-RAD2010, TEGO-RAD2500, T EGO-RAD2600, TEGO-RAD2700 (manufactured by Evonik Japan), Mega Examples include the FACK RS854 (manufactured by DIC Corporation).

[0147] Examples of commercially available fluorine-based antifouling agents include Optool DAC and Optool DSX. (Manufactured by Ikin Industries Co., Ltd.), MegaFac RS71, MegaFac RS74 (Manufactured by DIC Corporation), LI NC152EPA, LINC151EPA, LINC182UA (manufactured by Kyoeisha Chemical Co., Ltd.), F Examples include the Turgent 650A, Turgent 601AD, and Turgent 602. ru.

[0148] Examples of commercially available antifouling agents that are fluorine-based and silicone-based and have reactive functional groups include, Megafuck RS851, Megafuck RS852, Megafuck RS853, Megafuck DIC RS854, Opstar TU2225, Opstar TU2224 (J Examples include SR Corporation's X71-1203M (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0149] <<Resin layer>> The resin layer 13 is a layer made of a light-transmitting resin. The resin layer 13 has shock absorption properties. It is a layer having a resin layer. The resin layer may have a multilayer structure consisting of two or more resin layers.

[0150] The thickness of the resin layer 13 is between 50 μm and 300 μm. If the thickness is less than 50 μm, the hardness of the resin layer may decrease, and if it exceeds 300 μm... This would result in a film thickness that is too thick, making it unsuitable for thinning and potentially worsening processability. The thickness of the resin layer was determined by taking a cross-sectional image of the resin layer using a scanning electron microscope (SEM). The thickness of the resin layer was measured at 20 locations in the cross-sectional image, and the arithmetic mean of the thickness at those 20 locations was calculated as follows: The method for taking cross-sectional photographs of the resin layer is the same as the method for taking cross-sectional photographs of the hard coat layer. The lower limit of the resin layer 13 is more preferably 60 μm or more, and the upper limit of the resin layer 13 is 1 It is more preferable that the particle size be 50 μm or less, and even more preferable that it be 100 μm or less.

[0151] The resin constituting the resin layer 13 is suitable for use in the optical film 10 at 25°C and 500Hz or higher. The shear storage modulus G' and shear loss modulus G'' in the frequency range below 1000 Hz are within the above range. The resin is not particularly limited as long as it fits within the enclosure. Examples of such resins include acrylic. Examples include urethane-based gels, silicone-based gels, urethane-based resins, and epoxy-based resins. These are preferred. Among these, acrylic gels are preferred. "Gel" generally refers to a high viscosity gel. This refers to a dispersed system that has lost its fluidity. The resin layer 13 is made of acrylic gel, urethane resin, etc. In addition, it may contain rubber or thermoplastic elastomers.

[0152] (Acrylic gel) Acrylic gels include those containing acrylic acid esters, which are used in adhesives and other applications. Various polymers can be used as long as they are obtained by polymerizing nomers. Specifically, Examples of acrylic gels include ethyl (meth)acrylate and n-propyl (meth ) Acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate i-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-ethylhexyl Xyl(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 Relate, i-nonyl(meth)acrylate, i-decyl(meth)acrylate, tride Sil(meth)acrylate, stearyl(meth)acrylate, i-stearyl(meth) Polymerized or copolymerized acrylic monomers such as acrylates can be used. In this specification, "(meth)acrylate" means "acrylate" and "methacrylate". This means both "relate" and "polymerize". Furthermore, the acrylic acid used in the above (co)polymerization process is... Esters can be used alone or in combination of two or more types.

[0153] (Urethane resin) Urethane resins are resins that have urethane bonds. As for urethane resins, ionization Cured products of radiation-curable urethane resin compositions, cured products of thermosetting urethane resin compositions, etc. Among these, the one that offers high hardness, a fast curing speed, and excellent mass-producibility is... Therefore, it is preferable that the material is a cured product of an ionizing radiation-curable urethane resin composition.

[0154] The ionizing radiation-curable urethane resin composition contains urethane (meth)acrylate. Furthermore, the thermosetting urethane resin contains a polyol compound and an isocyanate compound. They exist. Urethane (meth)acrylates, polyol compounds, and isocyanate compounds. This may be a monomer, oligomer, or prepolymer.

[0155] The number of (meth)acryloyl groups (functional groups) in urethane (meth)acrylate is 2 or less. It is preferable that the value is 4 or less. (meth)acryloy in urethane (meth)acrylate If the number of ions is less than 2, the pencil hardness may be low, and if it exceeds 4, the hardness may be low. The shrinkage becomes excessive, causing the optical film to curl, and also causing cracks in the resin layer when bent. There is a risk of punctures. (meth)acryloyl groups in urethane (meth)acrylate The upper limit of the number is more preferably 3 or less. Note that "(meth)acryloyl group" means This means that it includes both the "acryloyl group" and the "methacryloyl group".

[0156] The weight-average molecular weight of urethane (meth)acrylate is between 1500 and 20000. It is preferable that the weight-average molecular weight of the urethane (meth)acrylate is less than 1500. If present, impact resistance may decrease, and if it exceeds 20,000, ionizing radiation hardening may occur. The viscosity of the urethane resin composition may increase, potentially leading to a deterioration in coating properties. (t) The lower limit of the weight-average molecular weight of the acrylate is more preferably 2000 or higher. It is more preferable that the limit be 15,000 or less.

[0157] Furthermore, as a repeating unit having a structure derived from urethane (meth)acrylate, for example, Examples include structures represented by the following general formulas (26), (27), (28), or (29). It can be done. [ka] In the above general formula (26), R 9 R represents a branched alkyl group, 10 is a branched-chain alkyl group R represents a group or a saturated cyclic aliphatic group. 11 R represents a hydrogen atom or a methyl group. 12 is hydrogen The characters represent an atom, a methyl group, or an ethyl group, where m is an integer greater than or equal to 0, and x is an integer between 0 and 3. .

[0158] [ka] In the above general formula (27), R 9 R represents a branched alkyl group, 10 is a branched-chain alkyl group R represents a group or a saturated cyclic aliphatic group. 11 R represents a hydrogen atom or a methyl group. 12 is hydrogen n represents an atom, a methyl group, or an ethyl group, n represents an integer of 1 or more, and x represents an integer from 0 to 3. .

[0159] [ka] In the above general formula (28), R 9 R represents a branched alkyl group, 10 is a branched-chain alkyl group R represents a group or a saturated cyclic aliphatic group. 11 R represents a hydrogen atom or a methyl group. 12 is hydrogen The characters represent an atom, a methyl group, or an ethyl group, where m is an integer greater than or equal to 0, and x is an integer between 0 and 3. .

[0160] [ka] In the above general formula (29), R 9 R represents a branched alkyl group, 10 is a branched-chain alkyl group R represents a group or a saturated cyclic aliphatic group. 11 R represents a hydrogen atom or a methyl group. 12 is hydrogen n represents an atom, a methyl group, or an ethyl group, n represents an integer of 1 or more, and x represents an integer from 0 to 3. .

[0161] Furthermore, the resin constituting the resin layer 13 depends on the structure of the polymer chains (repeating units). Whether it is formed can be determined, for example, by pyrolysis GC-MS and FT-IR, by the resin layer 13 This can be determined by analyzing the following. In particular, pyrolysis GC-MS is used to analyze the resin layer 13. It is useful because it allows for the detection of monomeric units as monomer components.

[0162] The resin layer 13 is in the optical film 10 at 25°C, 500Hz to 1000Hz. The shear storage modulus G' and shear loss modulus G'' in the lower frequency range are within the above range. If so, UV absorbers, spectral transmittance modifiers, antifouling agents, inorganic particles and / or organic particles, etc. It may contain UV absorbers, etc., as described in the section on hard coat layer 12. Since similar methods can be used, we will omit the explanation here.

[0163] <<<Other optical films>>> In the optical film 10 shown in Figure 1, the resin layer 13 is on the second surface 1 of the resin substrate 11. Although it is directly provided on 1B, as an optical film, the resin layer is connected to the resin substrate via an adhesive layer. It may also be an optical film attached to it. Specifically, the optical film shown in Figure 5 M40 consists of a resin substrate 11 and a hard coat provided on the first surface 11A side of the resin substrate 11. The layer 12 is provided on the second surface 11B side, which is the side opposite to the first surface 11A of the resin substrate 11. The device comprises a resin layer 13 and an adhesive layer 41 interposed between the resin substrate 11 and the resin layer 13. The resin layer 13 is attached to the resin substrate 11 via the adhesive layer 41. In Figure 5, the components that have the same reference numerals as in Figure 1 are the same components as those shown in Figure 1. Since it is already available, the explanation will be omitted.

[0164] In Figure 5, the surface 40A of the optical film 40 is the surface 12A of the hard coat layer 12. The back surface 40B of the optical film 40 is on the side of the resin substrate 11 in the resin layer 13. This is face 13A, which is the opposite side of the face.

[0165] In the optical film 40 as well, at 25°C and in the frequency range of 500Hz to 1000Hz The shear storage modulus G' is greater than 200 MPa and less than or equal to 1200 MPa, at 25°C The shear loss modulus G'' in the frequency range of 500Hz to 1000Hz is 3MPa or less. The upper limit is 150 MPa or less. The shear storage modulus G' and in optical film 40 The shear loss modulus G'' is the shear storage modulus G'' and shear loss modulus in the optical film 10. The elastic modulus G'' shall be measured by the same method as. Other parts of optical film 40 Since the properties are the same as those of the optical film 10, we will omit the explanation here.

[0166] <<Adhesive layer>> The adhesive layer 41 may be an adhesive film. The adhesive layer 41 is not particularly limited. However, for example, OCA (Optical Clear Adhesive) can be used. The thickness of the adhesive layer 41. It is preferable that the thickness is 5 μm or more. If the thickness of the adhesive layer 41 is 5 μm or more, the resin The resin layer 13 can be securely attached to the substrate 11. The lower limit of the thickness of the adhesive layer 41 is thin. From the viewpoint of mold formation, it is preferable that the particle size be 50 μm or less.

[0167] <<Manufacturing method for optical film>> The optical film 10 is manufactured by various methods depending on the type of resin that makes up the resin layer 13. It can be manufactured. For example, if the resin layer 13 is a layer made of acrylic gel, For example, it can be manufactured as follows: First, the first surface 11A of the resin substrate 11 On top of that, the first hard coat layer composition is applied using a coating device such as a bar coater. A coating film of the first hard coat layer composition is formed.

[0168] <Composition for the first hard coat layer> The composition for the first hard coat layer is polymerized to form the first hard coat layer 12B. It contains a chemical compound. The first hard coat layer composition also contains, as necessary, UV-resistant compounds. Contains a ray absorber, spectral transmittance modifier, antifouling agent, inorganic particles, leveling agent, solvent, and polymerization initiator. You can stay like that.

[0169] (solvent) The above solvents include alcohols (e.g., methanol, ethanol, propanol, isopodium). Lopanol, n-butanol, s-butanol, t-butanol, benzyl alcohol, PGME, ethylene glycol, diacetone alcohol), ketones (e.g., acetone, methyl ester), Ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, hep Tanone, diisobutyl ketone, diethyl ketone, diacetone alcohol), ester (vinegar) Methyl acetate, ethyl acetate, butyl acetate, n-propyl acetate, isopropyl acetate, methyl formate PGMEA, aliphatic hydrocarbons (e.g., hexane, cyclohexane), halogenated carbon dioxide Elements (e.g., methylene chloride, chloroform, carbon tetrachloride), aromatic hydrocarbons (e.g., benzyl sulfate, chloroform, carbon tetrachloride), (Zene, toluene, xylene), amides (e.g., dimethylformamide, dimethylacetamide) (e.g., N-methylpyrrolidone), ethers (e.g., diethyl ether, dioxane, tetramethyl ether) (Drofuran), ether alcohol (e.g., 1-methoxy-2-propanol), carbon Examples include methyl carbonate, diethyl carbonate, ethylmethyl carbonate, etc. The medium may be used alone, or two or more may be used in combination. In particular, the above solvent may be used In this process, components such as urethane (meth)acrylate, as well as other additives, are dissolved or dispersed. Therefore, in terms of being able to suitably coat the first hard coat layer composition, methyl isobutyl ketone, Methyl ethyl ketone is preferred.

[0170] (Polymerization initiator) Polymerization initiators are decomposed by ionizing radiation irradiation, generating radicals that contribute to the polymerization of polymerizable compounds. It is a component that initiates or promotes cross-linking.

[0171] Polymerization initiators release substances that initiate radical polymerization upon irradiation with ionizing radiation. If possible, it is not particularly limited. The polymerization initiator is not particularly limited and known ones may be used. They can be found in, for example, acetophenones, benzophenones, and Michler. Benzoyl benzoate, α-amyloxime ester, thioxanthone, propiophate Examples include ions, benzyl compounds, benzoins, and acylphosphine oxides. It is preferable to use a photosensitizer in combination, and a specific example of this is n-butyl Examples include mine, triethylamine, and poly-n-butylphosphine.

[0172] After forming a coating film of the first hard coat layer composition, the coating film can be removed by various known methods, for example The drying process involves heating at a temperature between 30°C and 120°C for 10 to 120 seconds. Evaporate the solvent.

[0173] After the coating film has dried, it is irradiated with ionizing radiation such as ultraviolet light to partially harden the coating film. To cure. In this specification, "partially cured" means that it will harden when further irradiated with ionizing radiation. This means that the process is essentially progressing. However, at this stage, the coating film is not fully cured. ) may be allowed. In this specification, "complete curing" means that even if ionizing radiation is applied further, This means that hardening will not progress substantially.

[0174] After the coating film has partially hardened, a second hard coating is applied to the coating film using a coating device such as a bar coater. A second hard coat layer composition is applied to form the coat layer 12C. Forms a coating film of the docoat layer composition.

[0175] <Composition for the second hard coat layer> The composition for the second hard coat layer is polymerized to form the second hard coat layer 12C. It contains a chemical compound. The composition for the second hard coat layer also contains, as necessary, UV-resistant compounds. It may contain a light absorber, a solvent, and a polymerization initiator. The second hard coat layer composition is Similar to the hard coat layer composition of 1, the total solids content is preferably 25-55%. The solvent and polymerization initiator are described in the first hard coat layer composition. Since it is similar to the drug, we will omit the explanation here.

[0176] After forming a coating film of the second hard coat layer composition, the coating film is removed by various known methods, for example. Dry by heating at a temperature between 30°C and 120°C for 10 to 120 seconds, then melt. Evaporate the agent.

[0177] After the coating film has dried, ionizing radiation such as ultraviolet light is applied to the coating film of the second hard coat layer composition. Irradiation is performed to create a coating film of the first hard coat layer composition and the second hard coat layer composition. The coating film is fully cured, and the first hard coat layer 12B and the second hard coat layer are applied. A coat layer 12C is formed to obtain a hard coat layer 12. After that, the hard coat layer 12 A resin layer composition is applied to the second surface 11B of the formed resin substrate 11, and the resin layer assembly It forms a coating film on the finished product.

[0178] <Composition for resin layer> The resin layer composition includes, for example, urethane (meth)acrylate. The finished product may also contain, as needed, UV absorbers, spectral transmittance adjusters, leveling agents, and solvents. It may also contain a polymerization initiator. The solvent and polymerization initiator are part of the composition for the first hard coat layer. The same solvents and polymerization initiators described in the section can be used.

[0179] After forming a coating film of the resin composition, it is dried, and then irradiated with ionizing radiation, The coating film of the resin layer composition is cured to form the resin layer 13. This results in the light shown in Figure 1. A film 10 is obtained.

[0180] Furthermore, to obtain the optical film 40 shown in Figure 5, first, in the same manner as above, A hard coat layer 12 is formed on the first surface 11A of the lipid substrate 11.

[0181] On the other hand, on one side of a release film such as polyethylene terephthalate film, After applying the lipid layer composition to form a coating film, it is dried, and then irradiated with ionizing radiation. Therefore, the coating film of the resin layer composition is cured to form the resin layer 13.

[0182] After forming a resin layer 13 on the release film, the release film is peeled off the resin layer 13. A resin layer 13 is obtained on its own. Then, the obtained resin layer 13 is attached to the resin substrate 1 via the adhesive layer 41. It is attached to the second surface 11B of 1. This yields the optical film 40 shown in Figure 5. It can be done.

[0183] <<<Image display device>>> Optical films 10 and 40 can be incorporated into a foldable image display device for use. It is possible. Figure 6 is a schematic diagram of the image display device according to this embodiment. As shown in Figure 6 To that end, the image display device 50 faces the observer, and mainly houses the battery and other components in its housing 51. , protective film 52, display panel 53, touch sensor 54, circular polarizing plate 55, and optical film The film 10 is stacked in this order. Between the display panel 53 and the touch sensor 54, Between the sensor 54 and the circular polarizer 55, and between the circular polarizer 55 and the optical film 10, A transient adhesive layer 56 is provided, and these members are fixed to each other by the adhesive layer 56. Furthermore, a black layer 57 is provided on a portion of the back surface 10B of the optical film 10. It is there. Furthermore, the adhesive layer 56 is between the display panel 53 and the touch sensor 54, and the touch sensor 5 It is positioned between 4 and the circular polarizer 55, and between the circular polarizer 55 and the optical film 10, The location of the adhesive layer is not particularly limited, as long as it is between the optical film and the display panel.

[0184] The optical film 10 is configured such that the hard coat layer 12 is on the observer side of the resin substrate 11. It is arranged. In the image display device 50, the hard coat layer 12 of the optical film 10 The surface 12A (the surface of the second hard coat layer 12C) of the image display device 50 is the surface 50A It constitutes [something].

[0185] In the image display device 50, the display panel 53 includes organic light-emitting diodes, etc. It is a photodiode panel. The touch sensor 54 is more of a display panel than a circular polarizing plate 55. Although it is positioned on the 53 side, even if it is positioned between the circular polarizer 55 and the optical film 10 That's good. Also, the touch sensor 54 may be an on-cell or in-cell type.

[0186] For example, OCA (Optical Clear Adhesive) can be used as the adhesive layer 56. However, from the viewpoint of improving impact resistance and preventing damage to the display panel 53, the above acrylic gel It is preferable to use an adhesive layer made of the above acrylic gel. When using an adhesive layer, between the display panel 53 and the touch sensor 54, the touch sensor 54 and The above A sticky layer should be placed. Also, since the above acrylic gel is sticky, the resin layer 13 When the above acrylic gel is used, an adhesive layer is placed between the circular polarizer 55 and the optical film 10. Even without providing 56, by directly attaching the resin layer 13 to the circular polarizing plate 55, circular polarization The plate 55 and the optical film 10 can be fixed together.

[0187] The shear loss tangent tanδ has traditionally been known as an indicator of shock absorption performance. Therefore, the structure comprises a hard coat layer on one side of the resin substrate and a resin layer on the other side. It is also conceivable to express the impact resistance of a constructed optical film as the shear loss tangent tanδ, The shear loss tangent tanδ is used when an impact is applied to the surface of the optical film (the surface of the hard coat layer). When this occurs, the surface of the optical film is dented due to the optical film itself, and the adhesive layer is also affected. The indentation on the surface of the optical film and the component located inside the image display device, beyond the optical film. Damage could not be suppressed. This is because the shear loss tangent tanδ is equal to the shear loss bullet. This is thought to be because it is the ratio (G'' / G'') of the shear modulus G'' to the shear storage modulus G''. The inventors of this invention conducted further research and found that when an impact is applied to the surface of an optical film... Surface dents caused by the optical film itself and surface dents caused by the adhesive layer, and the optical film In order to suppress damage to components located inside the image display device rather than the film, the resin layer The balance between film thickness, shear storage modulus G', and shear loss modulus G'' is important. It was released. According to this embodiment, a hard coat layer 12 is placed on the first surface 11A side of the resin substrate 11. In optical films 10 and 40 having a structure in which a resin layer 13 is provided on the second surface 11B side, The thickness of the lipid layer 13 is thin, between 50 μm and 300 μm, and optical films 10 and 4 When the above shear storage modulus G' at 0 exceeds 200 MPa and is 1000 MPa or less... Furthermore, the shear loss modulus G'' in the optical films 10 and 40 is 3 MPa or more. Since it is 50 MPa or less, it is foldable, yet the surface of the optical film 10 When an impact is applied to 10A, the surface 10A, 40 is affected by the optical film 10, 40 itself. The recess in A and the adhesive layer 56 located inside the image display device 50 beyond the optical film 10 This can suppress the resulting indentations on the surfaces 10A and 40A of the optical films 10 and 40. Both methods can suppress damage to components such as the display panel 53 located inside the image display device 50. This allows for excellent impact resistance. [Examples]

[0188] To explain the present invention in detail, examples will be given below, but the present invention is these Not limited to the description. Furthermore, the "100% solid content equivalent" below refers to the solid content in the solvent-diluted product. This is the value when the minutes are set to 100%.

[0189] <Preparation of compositions for hard coat layers> First, a composition for a hard coat layer was obtained by blending each component to achieve the composition shown below. .

[0190] (Composition for hard coat layer 1) • Dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate Mixture of t (product name "M403", manufactured by Toagosei Co., Ltd.): 25 parts by mass • Dipentaerythritol EO-modified hexaacrylate (product name "A-DPH-6E") Shin Nakamura Chemical Co., Ltd.): 25 parts by mass • Irregularly shaped silica particles (average particle size 25 nm, manufactured by JGC Catalysts & Chemicals Co., Ltd.): 50 parts by mass (solid content 10%) (0% equivalent value) • Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacu") RE (registered trademark) 184, manufactured by BASF Japan): 4 parts by mass • Fluorine-based leveling agent (product name "F568", manufactured by DIC Corporation): 0.2 parts by mass (solid content 1 (00% equivalent value) Methyl isobutyl ketone (MIBK): 150 parts by mass

[0191] (Composition for hard coat layer 2) • Urethane acrylate (product name "UX5000", manufactured by Nippon Kayaku Co., Ltd.): 25 parts by mass • Dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate Mixture of t (product name "M403", manufactured by Toagosei Co., Ltd.): 50 parts by mass • Polyfunctional acrylate polymer (product name "Acrit 8KX-012C", Taisei Fine) Chemical Co., Ltd.): 25 parts by mass (calculated based on 100% solid content) • Antifouling agent (product name "BYKUV3500", manufactured by Bic Chemie): 1.5 parts by mass (solids) (100% equivalent value) • Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacu") RE (registered trademark) 184, manufactured by BASF Japan): 4 parts by mass Methyl isobutyl ketone (MIBK): 150 parts by mass

[0192] <Preparation of composition for resin layer> First, a resin layer composition was obtained by blending each component to achieve the composition shown below. (Composition 1 for resin layer) • Urethane acrylate (product name "UV3310B", manufactured by Nippon Synthetic Chemical Co., Ltd., bifunctional): 8 5 parts by mass • Phenoxyethyl acrylate (product name "Viscoat #192", Osaka Organic Chemical Industry Co., Ltd.) ): 5 parts by mass • Tripentaerythritol acrylate, mono and dipentaerythritol acrylate A mixture of biscoat and polymentaerythritol acrylate (product name "Biscuits # 802, manufactured by Osaka Organic Chemical Industry Co., Ltd.): 10 parts by mass • Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacur") e(registered trademark)184, manufactured by BASF Japan): 5 parts by mass Methyl isobutyl ketone: 10 parts by mass

[0193] (Composition 2 for resin layer) • Urethane acrylate (product name "UV3310B", manufactured by Nippon Synthetic Chemical Co., Ltd., bifunctional): 8 5 parts by mass • Phenoxyethyl acrylate (product name "Viscoat #192", Osaka Organic Chemical Industry Co., Ltd.) ): 15 parts by mass • Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacur") e(registered trademark)184, manufactured by BASF Japan): 5 parts by mass Methyl isobutyl ketone: 10 parts by mass

[0194] (Composition 3 for resin layer) • Urethane acrylate (product name "UV3310B", manufactured by Nippon Synthetic Chemical Co., Ltd., bifunctional): 8 0 parts by mass • Phenoxyethyl acrylate (product name "Viscoat #192", Osaka Organic Chemical Industry Co., Ltd.) ): 5 parts by mass • Tripentaerythritol acrylate, mono and dipentaerythritol acrylate A mixture of biscoat and polymentaerythritol acrylate (product name "Biscuits # 802, manufactured by Osaka Organic Chemical Industry Co., Ltd.): 10 parts by mass • Dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate A mixture of phosphates (product name "KAYARAD DPHA", manufactured by Nippon Kayaku Co., Ltd.): 5 parts by mass • Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacur") e(registered trademark)184, manufactured by BASF Japan): 5 parts by mass Methyl isobutyl ketone: 10 parts by mass

[0195] (Composition 4 for resin layer) • Urethane acrylate (product name "UV3310B", manufactured by Nippon Synthetic Chemical Co., Ltd., bifunctional): 9 5 parts by mass • Phenoxyethyl acrylate (product name "Viscoat #192", Osaka Organic Chemical Industry Co., Ltd.) ): 5 parts by mass • Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacur") e(registered trademark)184, manufactured by BASF Japan): 5 parts by mass Methyl isobutyl ketone: 10 parts by mass

[0196] (Composition 5 for resin layer) • Urethane acrylate (product name "UV3310B", manufactured by Nippon Synthetic Chemical Co., Ltd., bifunctional): 8 5 parts by mass • Dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate A mixture of phosphates (product name "KAYARAD DPHA", manufactured by Nippon Kayaku Co., Ltd.): 15g Department • Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacur") e(registered trademark)184, manufactured by BASF Japan): 5 parts by mass Methyl isobutyl ketone: 10 parts by mass

[0197] <Example 1> As a resin substrate, a 50 μm thick polyimide substrate (product name "NeoPrim", Mitsubishi Gas Chemical Co., Ltd.) is used. Prepare a polyimide substrate (manufactured by Gakusha) and harden one side of the polyimide substrate (the first side) with a bar coater. Coating layer composition 1 was applied to form a coating film. Then, the formed coating film was subjected to 70°C By heating for 1 minute, the solvent in the coating film is evaporated, and then the ultraviolet irradiation device (fusion) is used. Using a light source (H bulb) manufactured by UV System Japan, the total amount of ultraviolet light in the air is 1 00 mJ / cm 2 The coating was partially cured by irradiating it in this manner. Next, A hard coat layer is applied to the surface of the coating film of the semi-cured hard coat layer composition 1 using a bar coater. Composition 2 was applied to form a coating film. The formed coating film was heated at 70°C for 1 minute. This evaporates the solvent in the coating film, and the ultraviolet irradiation device (Fusion UV System J) Using a light source (H bulb) manufactured by Pan Co., under conditions where the oxygen concentration is 200 ppm or less, ultraviolet light is used. The cumulative light intensity is 200 mJ / cm². 2 The paint film is irradiated in such a way that it is fully cured. This resulted in a first hard coat layer with a thickness of 10 μm on the polyimide substrate, and a first hard coat layer with a thickness of 10 μm. A hard coat layer consisting of a second hard coat layer with a thickness of 5 μm laminated on top of the hard coat layer. A coating layer was formed. After forming a hard coating layer on the polyimide substrate, the polyimide substrate The resin layer composition 1 is applied to the second surface opposite to the first surface using a bar coater to form a coating film. The formed coating film was then heated to 70°C for 1 minute, thereby creating a coating film. The solvent is evaporated, and an ultraviolet irradiation device (manufactured by Fusion UV System Japan, light source H-bar) is used. Using a LUBB (Lubricant), the cumulative light intensity in the air was measured to be 1200 mJ / cm². 2 Irradiate in such a way The coating is then cured to form a resin layer made of urethane resin with a film thickness of 200 μm. An optical film was obtained.

[0198] The thickness of each layer was determined by taking cross-sectional images of each layer using a scanning electron microscope (SEM). In the image, the film thickness of each layer was measured at 20 locations, and the arithmetic mean of the film thicknesses at those 20 locations was measured. The specific method for taking cross-sectional photographs was as follows: First, cut into 1mm x 10mm sections. A block is prepared by embedding the extracted optical film in embedding resin, and from this block... Using a general sectioning method, uniform sections free of holes, etc., with a thickness of 70 nm to 100 nm were prepared. Cut out sections. Sections are prepared using the "Ultramicrotome EM UC7" (Leica Micromicrotome). (Kuro Systems Co., Ltd.) etc. were used. Then, uniform sections without holes, etc. were cut out. The remaining block was used as the measurement sample. Then, a scanning electron microscope (SEM) (product name) was used. Using the "S-4800" (manufactured by Hitachi High-Technologies Corporation), the cross-section of the measurement sample was measured. A photograph was taken. When taking a cross-sectional photograph using the S-4800 mentioned above, the detector should be set to "SE Cross-sectional observation was performed with an acceleration voltage of "5kV" and an emission current of "10μA". Regarding magnification, can you adjust the focus and distinguish the contrast and brightness of each layer? We adjusted the aperture as needed, between 100 and 100,000 times, while observing the results. Furthermore, we used a "beam monitor". I set the aperture to "3", the objective lens aperture to "3", and the WD to "8mm". The thickness of the polyimide substrate was also measured using the same method as for the film thickness of each layer described above. Example 2 - was carried out. In Example 6 and Comparative Examples 1-5, the substrate thickness and hardness were also controlled using the same method as in Example 1. The film thickness of the coating layer and the resin layer was measured.

[0199] <Example 2> In Example 2, the procedure was the same as in Example 1, except that the thickness of the resin layer was set to 50 μm. And so, an optical film was obtained.

[0200] <Example 3> In Example 3, the process was the same as in Example 1, except that the thickness of the resin layer was set to 300 μm. Then, an optical film was obtained.

[0201] <Example 4> In Example 4, the only difference was that resin layer composition 2 was used instead of resin layer composition 1. An optical film was obtained in the same manner as in Example 1.

[0202] <Example 5> In Example 5, the only difference was that resin layer composition 3 was used instead of resin layer composition 1. An optical film was obtained in the same manner as in Example 1.

[0203] <Example 6> As a resin substrate, a 50 μm thick polyimide substrate (product name "NeoPrim", Mitsubishi Gas Chemical Co., Ltd.) is used. Prepare a (manufactured by Gakusha) and apply a hard coat layer composition to the first surface of the polyimide substrate using a bar coater. Substance 1 was applied to form a coating film. The formed coating film was then heated at 70°C for 1 minute. By doing so, the solvent in the coating film is evaporated, and the ultraviolet irradiation device (Fusion UV System) Using a Japan-made H-bulb light source, the cumulative light intensity of ultraviolet light in the air was 100 mJ / cm². 2 The coating was irradiated to partially cure (half-cured) it. Next, the partially cured coating On the surface of the coating film of hard coat layer composition 1, hard coat layer composition 2 is applied with a bar coater. The material was spread and a coating film was formed. The formed coating film was then heated at 70°C for 1 minute. The solvent in the film is evaporated, and then the ultraviolet irradiation device (manufactured by Fusion UV System Japan, light source) is used. Using an H-bulb, under conditions where the oxygen concentration is 200 ppm or less, the accumulated light amount is 20 0 mJ / cm 2 The coating was irradiated in such a way that it was fully cured. A first hard coat layer with a thickness of 10 μm is placed on a polyimide substrate, and the first hard coat A hard coat layer is formed consisting of a second hard coat layer with a thickness of 5 μm, which is laminated on top of the existing layer. did.

[0204] On the other hand, a polyethylene terephthalate film with a thickness of 100 μm is used as a release film. (Product name "Cosmoshine A4100", manufactured by Toyobo Co., Ltd.) Bar coater -The resin layer composition 1 was applied to form a coating film. Then, 7 By heating at 0°C for 1 minute, the solvent in the coating film is evaporated, and then the UV irradiation device (Fusion) is used. Using a light source (H bulb) manufactured by YONN UV System Japan, ultraviolet light is used to measure the cumulative light quantity in the air. 1200 mJ / cm 2 The coating is cured by irradiating it to achieve a thickness of 200 μm. A resin layer made of urethane-based resin was formed. After the resin layer was formed, polyethylene terephthalate The film was peeled off the resin to obtain the resin layer alone.

[0205] Then, a 5 μm thick adhesive film is applied to the second surface of the polyimide substrate, opposite to the first surface. A resin layer is bonded via a layer (product name "Panaclean PD-S1", manufactured by Panac Co., Ltd.) I attached it and obtained an optical film.

[0206] <Comparative Example 1> Comparative Example 1 was conducted in the same manner as Example 1, except that the thickness of the resin layer was 350 μm. Then, an optical film was obtained.

[0207] <Comparative Example 2> In Comparative Example 2, the procedure was the same as in Example 1, except that the thickness of the resin layer was set to 30 μm. And so, an optical film was obtained.

[0208] <Comparative Example 3> In Comparative Example 3, an optical film was obtained in the same manner as in Example 1, except that Composition 4 for resin layer was used instead of Composition 1 for resin layer. An optical film was obtained in the same manner as in Example 1.

[0209] <Comparative Example 4> In Comparative Example 4, an optical film was obtained in the same manner as in Example 1, except that Composition 5 for resin layer was used instead of Composition 1 for resin layer. An optical film was obtained in the same manner as in Example 1.

[0210] <Measurement of G´, G´´, and tanδ> The shear storage modulus G´, shear loss modulus G´´, and shear loss tangent tanδ of the optical films according to the examples and comparative examples were measured. Specifically, first, the optical film was punched into a rectangular shape of 10 mm × 5 mm to obtain a sample. Then, two samples were prepared and attached to a solid shear jig, which is an option of a dynamic viscoelasticity measuring device (product name: "Rheogel-E4000", manufactured by UBM Co., Ltd.). Specifically, the solid shear jig includes a 1-mm-thick metal solid shear plate and two L-shaped metal fittings arranged on both sides of the solid shear plate. One sample was sandwiched between the solid shear plate and one L-shaped metal fitting, and the other sample was sandwiched between the solid shear plate and the other L-shaped metal fitting. In this case, the resin layer was on the side of the solid shear plate, and the hard coat layer was on the side of the L-shaped metal fitting. Then, the L-shaped metal fittings were tightened with screws to fix the samples. Next, a tensile test chuck consisting of an upper chuck and a lower chuck was attached to the dynamic viscoelasticity measuring device (product name: "Rheogel-E4000", manufactured by UBM Co., Ltd.), and the solid shear jig was installed between the upper chuck and the lower chuck at a chuck separation of 20 mm. The set temperature was 25°C, and the temperature was raised at a rate of 2°C / min. 、および剪断損失正接tanδを測定した。具体的には、まず、光学フィルムを10mm ×5mmの長方形状に打ち抜いて、サンプルとした。そして、このサンプルを2枚準備し 、動的粘弾性測定装置(製品名「Rheogel-E4000」、ユービーエム社製)のオプションで ある固体剪断用治具に取り付ける。具体的には、固体剪断用治具は、厚みが1mmの1枚 の金属製の固体剪断板と、この固体剪断板の両側に配置された2つのL型金具を備えてお り、固体剪断板と一方のL型金具との間で一方のサンプルを挟み、かつ固体剪断板と他方 のL型金具で他方のサンプルを挟んだ。この場合、樹脂層が固体剪断板側となり、ハード コート層がL型金具側となるようにサンプルを挟んだ。そして、ビスでL型金具間を締め て、サンプルを固定した。次いで動的粘弾性測定装置(製品名「Rheogel-E4000」、株 式会社ユービーエム社製)に上部チャックおよび下部チャックからなる引張り試験用チャ ックを取り付けた後、上部チャックと下部チャックの間に固体剪断用治具をチャック間距 離20mmで設置した。そして、設定温度を25℃とし2℃ / minで昇温させた。この In this state, while fixing the solid shear plate, two L-shaped brackets are subjected to a strain of 1% and a frequency of 500Hz or less. Dynamic viscoelasticity measurements of a solid were performed at 25°C while applying longitudinal vibrations in the range of 1000 Hz or less. The shear storage modulus G', shear loss modulus G'', and shear loss tangent tan of an optical film. δ was measured. Here, the frequency range in the optical film is between 500 Hz and 1000 Hz. In the region, the shear storage modulus G', shear loss modulus G'', and shear loss tangent tanδ are L-type The metal fittings were subjected to vertical vibrations of 500Hz, 750Hz, and 950Hz, respectively. At the frequency, the shear storage modulus G', shear loss modulus G'', and shear of the optical film The loss tangent tanδ was measured, and these shear storage modulus G', shear loss modulus G'' and The arithmetic mean of the shear loss tangent tanδ is calculated, and this measurement is repeated three times, and each time The three arithmetic mean values ​​obtained were then given an arithmetic mean.

[0211] <Impact Resistance Test> The process is carried out on the surface of 0.7mm thick soda glass, with the soda glass side facing the resin layer side. The optical films of the example and comparative example are placed directly on the surface, and weighed 100g from a height of 30cm. Impact resistance test A: A 30mm diameter steel ball is dropped onto the surface of the hard coat layer of an optical film. Each of these steps was performed three times. Additionally, on a 0.7mm thick soda glass, the soda glass side faced the resin layer side. The optical films according to the examples and comparative examples are made of an adhesive sheet with a thickness of 200 μm. Place it using the product name "High Transparency Double-Sided Tape 8146-2" (manufactured by 3M), at a height of 30 A 100g, 30mm diameter steel ball is placed at a position of cm above the surface of the hard coat layer of the optical film. Impact resistance test B, in which the object is dropped onto a surface, was performed three times for each test. In impact resistance tests A and B, iron The position from which the ball was dropped was changed each time. Then, the optical filter after impact resistance test A was used. In the room, visually inspecting whether there are indentations on the surface of the hard coat layer reveals that Also, the optical fiber after impact resistance test B was evaluated to see if any cracks had occurred in the soda glass. In the room, the presence of indentations on the surface of the hard coat layer was evaluated visually. The valuation results were as follows: (Evaluation of surface depressions in the hard coat layer) ○: When the hard court layer is observed from both the front and at an angle, the hard court No indentations were observed on the surface of the layer. △: When the hard coat layer is observed from the front, indentations can be seen on the surface of the hard coat layer. Although not visible from the outside, an indentation was observed on the surface of the hard coat layer when viewed at an angle. ×: When the hard court layer is observed both from the front and at an angle, the hard court A clear depression was observed on the surface of the layer. (Evaluation of soda glass breakage) ◎: The soda glass did not break. ○: The soda glass was scratched but did not break. △: The soda glass cracked 1-2 times. ×: Cracks occurred in the soda glass all three times.

[0212] <Continuous Folding Test> The optical films according to the examples and comparative examples were cut into rectangles of 30 mm x 100 mm. The sample created was then subjected to a durability test (product name "DLDMLH-FS", Yuasa Systems Machinery) The short side (30 mm) of the sample is fixed to the fixing part (manufactured by Kisha Co., Ltd.) as shown in Figure 3(C). Install it so that the minimum distance between the two opposing sides is 30 mm, and Continuous folding test in which the hard court layer side of the pull is folded 180° (the hard court layer is inside) A test was performed 100,000 times in which the fold was made so that the side with the resin layer facing outwards would crack or break at the bend. We checked for any breakage. The same procedure was also performed on the optical films related to the examples and comparative examples. The newly prepared sample is attached to the durability testing machine described above in the same manner as above, and the sample Continuous folding test in which the resin side is folded 180° (the hard coat layer is on the outside, and the resin layer A test involving folding the product so that the inner side is facing inward was performed 100,000 times, and no cracks or fractures occurred at the bending point. The following was investigated. The results of the continuous folding test were evaluated according to the following criteria. ○: No cracks or fractures occurred in the flexed area during any of the continuous folding tests. . ×: In any of the continuous folding tests, cracks or fractures occurred at the bending point.

[0213] <Pencil hardness> Pencil on the surface (hard coat layer) of the optical film according to the examples and comparative examples The hardness was measured according to JIS K5600-5-4:1999. When measuring pencil hardness, a 1kg load is applied to the pencil while it is moved at a speed of 1mm / second. Pencil hardness is determined by the pencil hardness test, which determines the pencil that does not scratch the surface of the optical film. The pencil should have a high hardness. Note that when measuring pencil hardness, multiple pencils with different hardness levels should be used. However, each pencil was subjected to a pencil hardness test five times, and at least four of those five tests were performed under fluorescent light with an optical filter. If no scratches are visible on the surface of the optical film when the surface of the material is observed through transmission, then this In the case of pencils of varying hardness, it was determined that no scratches were made on the surface of the optical film.

[0214] The results are shown in Table 1 below. [Table 1]

[0215] The results are described below. In the optical film relating to Comparative Example 1, the thickness of the resin layer was Because it was too thick, it had poor foldability. In the optical film of Comparative Example 2, the resin Because the layer thickness is too thin, it cannot absorb impact and cracked into soda glass in impact resistance test A. This occurs, and in impact resistance test B, it follows the plastic deformation of the adhesive sheet. As a result, the amount of indentation on the surface of the hard coat layer was large. The optical film according to Comparative Example 3 In this case, the shear storage modulus G' and the shear loss modulus G'' are too small, so the shock is absorbed. It could not be absorbed, and cracks occurred in the soda glass during impact resistance test A. (See Comparative Example 4) In optical films, the shear storage modulus G' is too large, and the shear loss modulus G' Because the '' is too small, it cannot absorb the impact, and the soda glass broke in impact resistance test A. This could sometimes occur, and it was also poor at folding.

[0216] In contrast, in the optical films according to Examples 1 to 6, the thickness of the resin layer and the shear storage munitions are different. The balance between the modulus of elasticity G' and the shear loss modulus G'' is good, so after impact resistance tests A and B, No indentations were observed on the surface of the soda-coat layer, and no cracks were found in the soda-lime glass. Furthermore, the optical films according to Examples 1 to 6 also showed good results in continuous folding tests. Ta.

[0217] In addition to the continuous folding test described above, in the optical films relating to Examples 1 to 6, 3 A sample made by cutting a 0mm x 100mm rectangle was tested on a durability testing machine (product name "D The short side (30mm) of the sample is secured to the "LDMLH-FS" (manufactured by Yuasa System Equipment Co., Ltd.). Each is fixed at the fixed point, and as shown in Figure 3(C), the minimum distance between the two opposing sides is 2 Mount it so that it is in mm, and fold the hard coat layer side of the sample 180°. Continued folding test (a test in which the hard coat layer is on the inside and the resin layer is on the outside) The process was repeated 100,000 times, and it was examined to see if any cracks or fractures occurred in the bent area. Or, no breakage occurred. Furthermore, optical films according to Examples 1 to 6 were prepared in the same manner as described above. The new sample was then subjected to the durability testing machine described above, with the minimum length of the two opposing sides being measured in the same manner as described above. Install them so that there is a 2mm gap, and fold the resin layer side of the sample 180°. Folding test (a test in which the hard coat layer is on the outside and the resin layer is on the inside) The process was repeated 100,000 times, and it was examined to see if any cracks or fractures occurred in the bent area. Or, no fracture occurred.

[0218] Furthermore, in the optical films according to Examples 1 to 6, a rectangle measuring 30 mm x 100 mm is formed. The shorter side (30 mm) of the sample prepared by setting the sample is such that the distance between the opposing sides of the sample is 3 The optical film is fixed to the fixing points which are arranged parallel to each other so that the distance is 0 mm, and then folded. In this state, a folding static test was performed, in which the product was left to stand at 70°C for 240 hours. After the test, the folding state is released by removing the fixing part from one side, and then at room temperature. After 30 minutes, the opening angle (see Figure 4(B)), which is the angle at which the optical film opens naturally, was measured. In addition, the opening angle of the optical films in Examples 1 to 4 is 100° or more, and in Example 5 It was larger than the opening angle of the optical film. From this result, the shear storage modulus G' is 800M. It was confirmed that good resilience is achieved when the Pa is less than Pa. The opening angle is as follows: When folding with the hard court layer on the inside, and when folding with the hard court layer on the outside. We conducted folding and static testing in both the folded and unfolded states, and adopted the one with the smaller angle.

[0219] Furthermore, the first hard coat layer and the second hard coat of the optical film according to Examples 1 to 6 When measured using the Martens hardness of the hard coat layer, the Martens hardness of the first hard coat layer was The hardness was 830 MPa, and the Martens hardness of the second hard coat layer was 500 MPa. The Martens hardness was measured using HYSITRON's "TI950 Tri Using "boIndenter", under the following measurement conditions, the first hard coat layer and the second A Berkovich indenter (triangular pyramid) is placed at the center of each cross-section of the hard coat layer. After indenting to 0 nm and holding for a certain period of time to relieve residual stress, the load is removed, and the final result after relaxation is achieved. The maximum load P is measured and the maximum load P is measured. max (μN) and the depression area A (nm) at a depth of 500 nm 2 ) and P max Calculated using / A. Martens hardness was obtained by measuring at 10 locations. The arithmetic mean of the values ​​was used. (Measurement conditions) ·Loading speed: 10nm / sec ·Holding time: 5 seconds ·Loading and unloading speed: 10nm / sec ·Measurement temperature: 25℃

[0220] Furthermore, the surface of the optical film according to Examples 1 to 6 (the surface of the hard coat layer) is #0 000 grade steel wool (product name "BON STAR", Nippon Steel Wool Co., Ltd.) Using (manufactured), 1 kg / cm³ 2 While applying the load, the friction reciprocates 10 times at a speed of 50 mm / second. Then, a visual inspection was conducted on the surface of the optical film to check for scratches, and scratches were found. It wasn't there. [Explanation of symbols]

[0221] 10, 40… Optical film 10A, 12A, 40A…Surface 11…Resin base material 11A...First face 11B...Second side 12…Hard court layer 12A...First hard court layer 12B...Second hard court layer 13… Resin layer 50…Image display device 53…Display panel 56…adhesive layer

Claims

1. A foldable, light-transmitting optical film used in an image display device, Resin substrate and A hard coat layer provided on the first surface side of the resin substrate, The resin substrate comprises a resin layer having a thickness of 50 μm or more and 300 μm or less, provided on the second surface side opposite to the first surface of the resin substrate, The resin substrate is a substrate made of polyimide resin, polyamide resin, polyamide-imide resin, or a mixture of two or more of these resins. The thickness of the resin substrate is 10 μm or more and 100 μm or less. The hard coat layer comprises a polymerizable compound, The thickness of the hard coat layer is 1 μm or more and 20 μm or less. The aforementioned resin layer contains a urethane-based resin, The shear storage modulus G' of the optical film in the frequency range of 500 Hz to 1000 Hz at 25°C is 400 MPa to 1200 MPa. The shear loss modulus G'' of the optical film in the frequency range of 500 Hz to 1000 Hz at 25°C is 20 MPa to 150 MPa. An optical film in which the shear loss tangent tanδ, which is the ratio of the shear loss modulus G'' to the shear storage modulus G'', is 0.10 or more and 0.

15.

2. The optical film according to claim 1, wherein no cracks or breaks occur when the optical film is folded 180° 100,000 times in a test in which the optical film is folded such that the distance between the opposing sides of the optical film is 30 mm.

3. The optical film according to claim 1 or 2, wherein the resin substrate is a substrate made of a polyimide resin, a polyamide resin, or a mixture thereof.

4. A foldable image display device, Display panel and The optical film according to any one of claims 1 to 3 is positioned on the observer side of the display panel, An image display device in which the hard coat layer of the optical film is located on the observer side of the resin substrate.

5. The image display device according to claim 4, further comprising an adhesive layer disposed between the optical film and the display panel.

6. The image display device according to claim 4 or 5, wherein the display panel is an organic light-emitting diode panel.

Images