Optical films, polarizing plates, and image display devices

Abstract

To provide an optical film which can be made thin and can improve adhesiveness between a first functional layer and a second functional layer, a polarizer comprising such an optical film, and an image display device.SOLUTION: An optical film 10 comprises a light transmissive substrate 11, a first functional layer 12, and a second functional layer 13 in this order. In the optical film 10, at least any one of the first functional layer 12 and the second functional layer 13 further includes a mixed layer 14 which contains an ultraviolet light absorber, is provided between the first functional layer 12 and the second functional layer 13, is adjacent to the first functional layer 12 and the second functional layer 13, and contains a component of the first functional layer 12 and a component of the second functional layer 13. A total film thickness of the first functional layer 12, the second functional layer 13 and the mixed layer 14 is 1 μm or more and 10 μm or less, and a ratio of the film thickness of the mixed layer 14 with respect to the total film thickness of the first functional layer 12, the second functional layer 13 and the mixed layer 14 is 0.6% or more and 40% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to optical films, polarizing plates, and image display devices. [Background technology]

[0002] In recent years, smartphones have been using organic light-emitting diode (OLED) elements as display elements. Development of image display devices such as these is progressing. Image display devices using organic light-emitting diode elements are Unlike light-receiving display devices such as liquid crystal displays, it is a self-emissive display device. Because it does not require a light source such as a backlight device, it is possible to make it thinner and lighter. be.

[0003] On the other hand, OLED elements can degrade due to ultraviolet light, so they are not suitable for use in image display devices. The functional layers, such as the adhesive layer of the embedded optical film, contain ultraviolet absorbers. There are such examples (see, for instance, Patent Documents 1 and 2).

[0004] Furthermore, Patent Document 2 describes a cured layer containing an ultraviolet absorber that substantially contains an ultraviolet absorber. Either there is none, or an overcoat layer is provided in which the amount of UV absorber is less than that of the cured layer. This has been disclosed. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-155213 [Patent Document 2] Japanese Patent Publication No. 2016-200709 [Overview of the project] [Problems that the invention aims to solve]

[0006] Currently, there is a demand for further thinning of image display devices. Therefore, image display There is also a demand for thinner optical films incorporated into the device. Furthermore, thinning of the functional layer of optical films is being considered.

[0007] However, simply reducing the thickness of the functional layer increases the concentration of the UV absorber in the functional layer. The reaction rate of polymerizable compounds that polymerize by ultraviolet light to form the functional layer becomes low. This reduces the effectiveness of the functional layer containing UV absorbers and other components adjacent to this functional layer. The adhesion to the energy layer becomes less.

[0008] Furthermore, simply reducing the thickness of the functional layer increases the concentration of the UV absorber in the functional layer. This may reduce the surface hardness and scratch resistance of the functional layer. When abrasion resistance decreases, scratches are more likely to occur during the manufacturing process.

[0009] Furthermore, when the concentration of UV absorbers in the functional layer increases, the UV absorbers become more likely to precipitate. This could lead to a decrease in durability.

[0010] Furthermore, as in Patent Document 2, a functional layer such as a hardened layer and an overcoat layer is laminated in two layers. In cases where the total thickness of the functional layer is thin, extreme ultraviolet radiation can occur between these two layers. When there is a difference in the concentration of the absorber, during durability testing, the functional layer containing a large amount of UV absorber and the UV absorber... Cracks may occur due to differences in thermal expansion between the functional layer, which has a low amount of heat-absorbing agent, and the surrounding functional layer.

[0011] This invention was made to solve the above problem. That is, to make it thinner An optical film that can do the above and improve the adhesion between the first functional layer and the second functional layer. The objective is to provide a polarizing plate and an image display device equipped with such an optical film. ru.

[0012] Furthermore, it can be made thinner, and has good surface hardness, good scratch resistance and good durability. Durable optical film, polarizing plate and image display device equipped with such optical film The purpose is to provide. [Means for solving the problem]

[0013] This invention includes the following inventions. [1] An optical film comprising a light-transmitting substrate, a first functional layer, and a second functional layer in this order. The light-transmitting substrate is a triacetylcellulose resin, a cycloolefin polymer. The first functional layer comprises at least one of a resin system and a (meth)acrylic resin. and at least one of the second functional layer contains an ultraviolet absorber, and the first functional layer and It is provided between the second functional layers, adjacent to the first functional layer and the second functional layer, and the The mixture further comprises a component of the first functional layer and a component of the second functional layer, and the first functional The total film thickness of the layer, the second functional layer, and the mixed layer is 1 μm or more and 10 μm or less. The thickness of the mixed layer relative to the total thickness of the first functional layer, the second functional layer, and the mixed layer An optical film with a percentage of 0.6% or more and 40% or less.

[0014] [2] An optical film comprising a light-transmitting substrate, a first functional layer, and a second functional layer in this order. That is, at least one of the first functional layer and the second functional layer contains an ultraviolet absorber. Furthermore, provided between the first functional layer and the second functional layer, and the first functional layer and the second functional layer A mixed layer adjacent to the functional layer and containing the components of the first functional layer and the components of the second functional layer is provided. In addition, the total film thickness of the first functional layer, the second functional layer, and the mixed layer is 1 μm or more. The thickness is 10 μm or less, and the thickness of the mixed layer is 0.02 μm or more and 1 μm or less, optical fiber Film.

[0015] [3] The mixed layer comprises at least one polymerizable compound on one side of the light-transmitting substrate. A first coating film of the functional layer composition is applied to form the first coating film, and the first coating film is partially cured. A second coating film of a second functional layer composition containing at least a polymerizable compound in the cured first coating film. The above is formed by forming the first coating film and curing the second coating film. The optical film described in [1] or [2].

[0016] [4] Any of the above [1] to [3], wherein the thickness of the mixed layer is 0.1 μm or more. The optical film described in item 1.

[0017] [5] The first functional layer and the second functional layer both contain the ultraviolet absorber, The optical film described in any one of items [1] through [4].

[0018] [6] The first functional layer contains the ultraviolet absorber, and the indentation of the first functional layer The optical film described in [1] above, wherein the hardness is between 50 MPa and 600 MPa.

[0019] [7] An optical film comprising a light-transmitting substrate and a functional layer, wherein the functional layer comprises nitrogen atoms The functional layer contains an ultraviolet absorber, and the film thickness of the functional layer is 1 μm or more and 10 μm or less, In the functional layer, the secondary ions in the depth direction of the functional layer are determined by time-of-flight secondary ion mass spectrometry. When the ON intensity was measured, in the first region with a thickness of 0.3 μm including the surface of the functional layer The intensity of secondary ions derived from the UV absorber is in relation to the depth direction of the functional layer. The UV absorber originating from the second region with a thickness of 0.3 μm, which includes the bisector that divides the layer in two. The ratio of the intensity of secondary ions is 1.1 or more and 4.0 or less, and the second region The intensity of secondary ions derived from the ultraviolet absorber is measured in the 0.3 μm thickness of the functional layer, including the back surface. The ratio of the intensity of secondary ions derived from the UV absorber in the third region is 1.2 or more and 4.0 or less. It is an optical film.

[0020] [8] The minimum intensity of secondary ions derived from the ultraviolet absorber in the first region is the functional layer In the fourth region from the boundary on the light-transmitting substrate side of the first region to the back surface The optical fiber described in [7] above, which is smaller than the minimum intensity of secondary ions derived from the UV absorber. Room.

[0021] [9] The functional layer contains at least one fluorine atom-containing compound and one silicon atom-containing compound. The optical films described in [7] or [8] above, including any of the above.

[0022]

[10] The functional layer contains the fluorine atom-containing compound and the time-of-flight type secondary ion mass Secondary ions derived from the fluorine atom-containing compound in the first region, as measured by analytical methods The intensity of the fluorine atom is derived from the fluorine atom-containing compound in the second and third regions. The optical film described in [9] above, wherein the intensity of each secondary ion is greater than that of the other secondary ions.

[0023]

[11] The functional layer contains the silicon atom-containing compound, and the time-of-flight type secondary ion mass Secondary ions derived from the silicon atom-containing compound in the first region as measured by analytical method The intensity of the compound originates from the silicon atom-containing compound in the second and third regions. The optical film described in [9] or

[10] above, wherein the intensity of each secondary ion is greater than that of the other secondary ions.

[0024]

[12] An optical film as described in any one of the above items [1] to

[11] , and the optical film A polarizing plate comprising a polarizer provided on one side of the film.

[0025]

[13] A display element and an optical film according to any one of the above [1] to

[0011] or a polarizing plate according to the above

[12] , which is positioned on the observer side of the display element. Image display device.

[0026]

[14] The image table described in

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

[0027] According to one aspect of the present invention, it is possible to make the material thinner, and the first functional layer and the second functional layer Optical film capable of improving adhesion; polarizing plate equipped with such optical film. And an image display device can be provided.

[0028] According to another aspect of the present invention, it is possible to make the surface thinner and have good surface hardness and good durability. Optical film having scratch resistance and good durability, polarizing film having such optical film A board and an image display device can be provided. [Brief explanation of the drawing]

[0029] [Figure 1] Figure 1 is a schematic diagram of the optical film according to the first embodiment. [Figure 2] Figures 2(A) to 2(C) schematically illustrate the folding test. [Figure 3] Figure 3 is a plan view of the sample used for the folding test. [Figure 4] Figures 4(A) and 4(B) schematically show the manufacturing process of an optical film according to the first embodiment. [Figure 5] Figures 5(A) and 5(B) schematically show the manufacturing process of an optical film according to the first embodiment. [Figure 6] Figure 6 is a schematic diagram of the polarizing plate according to the first embodiment. [Figure 7] Figure 7 is a schematic diagram of the image display device according to the first embodiment. [Figure 8] Figure 8 is a schematic diagram of the optical film according to the second embodiment. [Figure 9] Figure 9 is a magnified view of a portion of the optical film shown in Figure 8. [Figure 10] Figure 10 is a plan view of the sample used to identify the position for measuring the in-plane phase difference. [Figure 11] Figures 11(A) and 11(B) schematically show the manufacturing process of an optical film according to the second embodiment. [Figure 12] Figures 12(A) and 12(B) schematically show the manufacturing process of an optical film according to the second embodiment. [Figure 13] Figure 13 is a schematic diagram of the polarizing plate according to the second embodiment. [Figure 14] Figure 14 is a schematic diagram of the image display device according to the second embodiment. [Figure 15] Figure 15 shows the depth profile of the hard coat layer measured by time-of-flight secondary ion mass spectrometry in the optical film according to Example B1. [Modes for carrying out the invention]

[0030] [First Embodiment] The following describes an optical film and an image display device according to the first embodiment of the present invention, with reference to the drawings. This will be explained with reference. In this specification, terms such as "film" and "sheet" are nominal terms. They are not distinguished from one another solely on the basis of differences. Therefore, for example, "Fi The term "lum" is used to include components that can also be called sheets. Figure 1 shows the embodiment This is a schematic diagram of the optical film in question, and Figures 2(A) to 2(C) show the folding test in progress. This is a schematic diagram, and Figure 3 is a plan view of the sample used in the folding test. Figures 4 and 5 schematically illustrate the manufacturing process of the optical film according to this embodiment.

[0031] <<<<Optical film>>>> The optical film 10 shown in Figure 1 consists of a light-transmitting substrate 11, a first functional layer 12, and a second functional layer The optical film 10 has the functional layers 13 in this order. The optical film 10 has the first functional layer 12 and the second functional layer 13 It further comprises a mixed layer 14 formed between them. In this specification, “functional layer” means light In a film, this is a layer intended to perform some function. Specifically, Functional layers include, for example, a base layer to improve adhesion with light-transmitting substrates, and a hard coat layer. A light layer, spectral transmittance adjustment layer, anti-glare layer, invisibility layer, refractive index adjustment layer, anti-fouling layer, or these Combinations and the like are examples. In this embodiment, the "functional layer" has a single-layer structure.

[0032] The thickness (overall thickness) of the optical film 10 is between 5 μm and 80 μm. Preferably, if the thickness of the optical film 10 is 5 μm or more, the desired pencil hardness can be obtained. Furthermore, if the thickness is 80 μm or less, the optical film 10 can be made thinner. By controlling the thickness of the optical film 10 in this way, the optical film 10 can be used to display images. When incorporated into a display device, it becomes possible to reduce the overall thickness of the image display device, and as a result This also makes weight reduction possible. The lower limit of the thickness of the optical film 10 is the mechanical strength of the optical film 10. From the viewpoint of ensuring [something], a thickness of 8 μm or more, 10 μm or more, or 15 μm or more is preferable. Also, From the perspective of further thinning the optical film 10, the thickness should be 50 μm or less, 40 μm or less, or A particle size of 30 μm or less is preferred.

[0033] Furthermore, in order to impart flexibility to the optical film 10, as will be described later, light transmission Depending on the resin system of the substrate 11, the thickness of the optical film 10 is 73 μm or less, and even 63 μm or less. It is preferable to have a diameter of μm or less. In particular, even if the gap φ between the edges in the folding test described later is small, From the perspective of not being affected by the folding direction, the thickness of the optical film 10 should be 48 μm or less, and even 43 μm. m or less is preferable. Also, in order to obtain flexibility while ensuring mechanical strength, light The thickness of the film 10 is preferably 21 μm or more, and more preferably 28 μm or more.

[0034] The total film thickness of the first functional layer 12, the second functional layer 13, and the mixed layer 14 is 1 μm to 10 μm. The following applies: If the total film thickness is 1 μm or more, strong adhesion will be observed in these layers. This ensures durability. Furthermore, if the total film thickness is 10 μm or less, it allows for thinner designs. In the optical film of the present invention, the majority of the thickness is occupied by a light-transmitting substrate. Therefore, depending on the design of the final image display device, the light-transmitting substrate may not be thin. In some cases, unless the thickness of the mixed layer 14 is reduced, the light described above will not be visible. The overall thickness of the film should be 80 μm or less, or 50 μm or less, which provides particularly good flexibility. This becomes difficult. Conventionally, for example, a single layer of functional material with a thickness of 10 μm was sufficient. In order to secure that, a large amount of functional ingredients must be added to the functional layer, As a result, there is a lack of components that can provide adhesion to the light-transmitting substrate in the functional layer, resulting in poor Adhesion is impossible to achieve. Therefore, we need to obtain the amount of component that provides adhesion to the light-transmitting substrate. To achieve this, it is necessary to reduce the concentration of the functional component in the functional layer. With the degree reduced, sufficient In order to ensure functionality, the thickness of the functional layer must be increased. Also, conventionally, Therefore, as mentioned above, there is a lack of components that provide adhesion to the light-transmitting substrate, The film also lacked sufficient physical strength.

[0035] The lower limit of this total film thickness is 1.5 μm or more, 2 μm or more, from the viewpoint of ensuring mechanical strength. Alternatively, it is preferable that it be 2.5 μm or more. Furthermore, this upper limit of the total film thickness may be further reduced. From the perspective of achieving a certain degree of micronization, the particle size may be 9 μm or less, 8 μm or less, or 5 μm or less.

[0036] The surface 10A of the optical film 10 shown in Figure 1 becomes the surface 13A of the second functional layer 13. However, if the third functional layer is formed on the surface of the second functional layer, the optical film The surface of the layer becomes the surface of the third functional layer. In this specification, "surface of the functional layer" refers to the functional layer This refers to the side opposite to the side of the light-transmitting substrate.

[0037] In the optical film 10, the spectral transmittance at a wavelength of 380 nm is less than 10%. It is preferable that the spectral transmittance of the optical film 10 at a wavelength of 380 nm is 10 If it is less than %, the photodegradation of the polarizer can be suppressed. Spectral transmittance at the above wavelength of 380 nm From the perspective of further suppressing the photodegradation of polarizers, the values ​​should be 8% or less, 5% or less, or 1% or less. It is preferable to do so.

[0038] In the optical film 10, the spectral transmittance at a wavelength of 410 nm is 20% or less. It is preferable that the spectral transmittance of the optical film 10 at a wavelength of 410 nm is 20 If the value is below %, the photodegradation of display elements, such as OLED elements, can be further suppressed. (Above wavelength 4) The spectral transmittance at 10nm should be 18% or less, from the viewpoint of suppressing photodegradation of the display element. It is preferable that the percentage be 5% or less, or more preferably 10% or less.

[0039] In the optical film 10, the spectral transmittance at a wavelength of 440 nm is 75% or more. It is preferable that the spectral transmittance of the optical film 10 at a wavelength of 440 nm is 75 If the percentage is above %, the reduction in visibility due to coloring can be suppressed. Spectral view at the above wavelength of 440 nm The transmittance is set at 78% or higher, 80% or higher, from the perspective of further suppressing the reduction in visibility due to coloring. It is more preferable that the percentage be 85% or higher.

[0040] The above spectral transmittance was obtained by measuring an optical film cut to a size of 50mm x 50mm. A spectrophotometer capable of measuring in 0.5nm increments (product name "UV-2450", Shimadzu Corporation) Light transmittance of optical film inside (manufactured by the factory, light source: tungsten lamp and deuterium lamp) With the substrate facing the light source, the following measurement conditions were used: wavelength 380nm, 41 Transmittance of at least 5 points within 1 nm before and after 0 nm and 440 nm, respectively. The value shall be determined by measuring the wavelength and calculating its average value. The spectral transmittances at 410 nm and 440 nm were obtained by measuring each wavelength three times. The arithmetic mean of the values ​​is used. Also, if there is a fluctuation in the spectral transmittance spectrum, Smoothing may be performed at a 5.0nm wavelength. Alternatively, the optical film may be made to the above size. If it cannot be cut out, the above size applies if it is 15mm x 40mm or larger. It doesn't have to be that way. (Measurement conditions) ·Wavelength range: 300nm~780nm • Scan speed: High Slit width: 2.0 • Sampling interval: Auto (0.5nm intervals) ·Lighting:C • Light source: D2 and WI ·Field of view: 2° • Light source switching wavelength: 360nm S / R switching: Standard • Pixel: PM • Auto-zero: Performed at 550nm after baseline scan. ·Temperature: 23±5℃ • Relative humidity: 30% to 70%

[0041] The spectral transmittance of optical film 10 is extremely low, less than 1% up to a wavelength of 380 nm, and wavelength It is acceptable for the wavelength to gradually increase from 410 nm and then increase sharply around 440 nm. Specifically, for example, in the optical film 10, wavelengths between 380 nm and 440 nm are divided The light transmittance may change in a way that follows a sigmoid curve.

[0042] The optical film 10 preferably has a blue light shielding rate of 20% or more. - If the light shielding rate is 20% or more, the problems caused by blue light, which will be discussed later, will be sufficiently addressed. It can be resolved. The above blue light shielding rate is, for example, for a 50mm x 50mm size. The optical film cut out is measured using a spectrophotometer capable of measuring spectral transmittance in 0.5 nm increments. Product name: "UV-2450", manufactured by Shimadzu Corporation, light source: tungsten lamp and heavy With the optical film placed inside the hydrogen lamp so that the light-transmitting substrate side faces the light source, In the wavelength range of 300nm to 780nm, there is a minimum of 5 transmission points within a 1nm margin before and after each wavelength. The rate is measured. Then, the blue light cut rate (%) is defined as A, and the wavelength is 380nm to 500nm. Let B be the average value (%) of the transmittance in nm, and the average value of the transmittance at wavelengths from 500 nm to 650 nm. Let C be the %) value, and calculate the blue light cut rate using the following formula (1). Note that blue light The shielding rate shall be the arithmetic mean of the values ​​obtained from three measurements. Furthermore, the measurement conditions for spectral transmittance shall be as follows. The above-mentioned measurement conditions for spectral transmittance at wavelengths of 380 nm, 410 nm, and 440 nm. It is similar to that. A = {1 - (B / C)} × 100 …(1)

[0043] The optical film 10 preferably has a yellow index (YI) of 15 or less. If the YI of the optical film 10 is 15 or less, the yellow tint of the optical film 10 can be suppressed. It can also be used in applications where transparency is required. Yellow Index (YI) is 50mm x Optical film cut to a size of 50 mm, at a temperature of 23±5℃ and relative humidity of 30% or less. Under conditions of 70% humidity or less, a spectrophotometer (product name "UV-2450", Shimadzu Corporation) is used. (Manufactured, light source: tungsten lamp and deuterium lamp) The light-transmitting substrate side is the light source side. From the transmittance of the optical film at wavelengths of 300nm to 780nm measured in the position shown above, The chromaticity tristimulus values ​​X, Y, and Z are calculated according to the formula described in JIS Z8722:2009. Calculate the tristimulus values ​​X, Y, and Z using the formula described in ASTM D1925:1962. Therefore, it is the value that is calculated. The Yellow Index (YI) is for one optical film. The transmittance at wavelengths of 300nm to 780nm is measured three times, and the result is calculated three times. The arithmetic mean of the obtained values ​​is used. Note that in the case of UV-2450, yellow ink Dex uses a personal computer (PC) connected to the UV-2450 to perform the above-mentioned transparency test. By loading the transient measurement data and checking the "YI" item in the calculation items, This is how it is calculated. The measurement conditions for transmittance at wavelengths of 300nm to 780nm are as follows: The measurement conditions for spectral transmittance at m, 410 nm, and 440 nm are the same as for YI. The lower limit is preferable from the perspective of ensuring high transparency, but UV absorption performance is also important. When considering the contribution, it is more preferable to have 1 or more, 2 or more, or 3 or more. Furthermore, if YI is too large, the color may become too yellow. Therefore, The upper limit is set to 10 or less, 7 or less, or from the viewpoint of further suppressing the yellowing of the optical film 10. It is more preferable that the value be 6 or less.

[0044] The optical film 10 preferably has a total light transmittance of 80% or more. If the total light transmittance of 10 is 80% or higher, sufficient optical performance can be obtained. The total light transmittance of film 10 should be 88% or higher, or 89% or higher, from the perspective of obtaining better optical performance. It is preferable that the percentage is above or above 90%.

[0045] The above total light transmittance is measured under conditions of 23±5°C and relative humidity between 30% and 70%. In accordance with JIS K7361-1:1997, haze meter (product name "HM-15") Using "0" (manufactured by Murakami Color Technology Laboratory Co., Ltd.), an optical film measuring 50mm x 50mm was used. After cutting to size, ensure that the light-transmitting substrate is free from curls, wrinkles, fingerprints, dust, etc. The device is positioned so that it is on the light source side, and measurements are taken three times for each optical film. The arithmetic mean of the measured values ​​is used. In this specification, "measure three times" means measuring the same location three times. This means measuring three different points, rather than measuring a single point. (Optical film) 10 has a visually observable flat surface, and the laminated layers such as the first functional layer 12 are also flat. Furthermore, variations in thickness should be kept within ±10% of the average thickness, preferably within ±5%. Therefore, the total light transmittance at three different locations on the cut optical film can be measured. This is thought to allow us to obtain the approximate average value of the total light transmittance across the entire surface of the optical film. If the optical film cannot be cut to the above size, for example, HM-150 is Since the entrance opening for measurement is 20mm in diameter, the size of the object must be at least 21mm in diameter. A sample will be needed. Therefore, an optical film of at least 22mm x 22mm in size will be required. You may cut it out as you see fit. If the optical film is small, make sure the light source spot does not fall off. Shift the frame slightly or change the angle to create three measurement points. Optical film In case 10, the variation in the obtained total light transmittance is due to the measurement area being 1m x 3000m long. Even if it's a 100-degree camera, or even if it's the size of a 5-inch smartphone, the average total light transmittance The value is within ±10%.

[0046] The optical film 10 preferably has a haze value (total haze value) of 1% or less. If the haze value of film 10 is 1% or less, the optical film 10 can be used in a mobile device. In this case, screen whitening can be suppressed. The upper limit of the haze value of the optical film 10 further suppresses whitening. From that perspective, the percentages are 0.5% or less, 0.4% or less, 0.3% or less, or 0.2% or less. It is preferable to do so.

[0047] The above haze values ​​are obtained under conditions of a temperature of 23±5℃ and a relative humidity of 30% to 70%. Using an isometer (product name "HM-150", manufactured by Murakami Color Technology Laboratory Co., Ltd.) JIS It can be measured by a method compliant with S K7136:2000. Specifically, The IZ value is measured using the same method as the method for measuring total light transmittance.

[0048] The pencil hardness of the surface 10A of the optical film 10 is preferably 3B to 2H. The pencil hardness test involves applying a pencil to the surface of an optical film cut to a size of 50mm x 100mm. Pencil hardness tester (product name "Pencil scratch coating hardness tester (electric type)", Toyo Sei Co., Ltd.) Using a machine manufactured by Kiseisakusho, under conditions of 23±5℃ and relative humidity between 30% and 70% While applying a 300g load to a pencil (product name "Uni," manufactured by Mitsubishi Pencil Co., Ltd.), the pencil was drawn 3mm / This shall be done by moving the object at a speed of 1 second. Pencil hardness is determined by the pencil hardness test. The highest hardness at which the surface of the optical film 10 remains unscratched is defined as the hardness at which the pencil hardness measurement is performed. The hardness test is performed using multiple pencils with different hardness levels, with each pencil undergoing five hardness tests. If, after performing this procedure, no scratches appear on the surface of the optical film 10 in 4 or more out of 5 attempts, then In the case of pencils of varying hardness, it is determined that no scratches were made on the surface of the optical film 10. The above scratches are The surface of the optical film 10 that underwent a pencil hardness test was observed under fluorescent light, and what was visible was It refers to that.

[0049] Under conditions of a temperature of 23±5℃ and a relative humidity of 30% to 70%, the optical film 10 In contrast, the distance φ between opposing sides of the optical film 10 becomes 6 mm, and the second functional layer 13 is inside The test involves folding the item 180° so that it faces one side (folding test) 100,000 times, 200,000 times, and 500,000 times. Even if repeated 1 million times, the optical film 10 will not crack or break. It is preferable that this does not occur. The optical film 10 is subjected to a folding test 100,000 times. If this occurs, the optical film 10 may crack or break, and the folding of the optical film 10 will The material becomes less durable. Furthermore, the more times it is folded, the more prone it becomes to cracking or breaking. Therefore, the above folding count will be 200,000, 300,000, 500,000, or 1,000,000 times. The optical film will not crack or break after the test, provided that the number of folds is 100,000. Technically, the optical film does not crack or break after the folding test. There is a significant difference. Furthermore, the number of folds in the above folding test should be evaluated at least 100,000 times. The reason for this is as follows: For example, optical films can be made into foldable smart If we consider integrating it into a phone, the frequency of folding (opening and closing) is very high. Therefore, the above folding test is evaluated by setting the number of folds to, for example, 10,000 or 50,000 times. This may prevent practical evaluation. Specifically, for example, Assuming someone constantly uses their smartphone, at least five times during their morning commute on trains or buses. Since it's estimated that you'll open and close your smartphone about 10 times a day, you'll need to do at least 3 times a day. It is assumed that the smartphone will be opened and closed 0 times per day. Therefore, the smartphone will be used 1 day. Assuming 30 opening and closing cycles, a folding test involving 10,000 folding cycles would be 30 times x 3 65 days equals 10,950 times, so this test simulates one year of use. Even if the results of a folding test involving 10,000 folding cycles are good, after one year, the optical fiber... There is a risk of cracking or breaking of the film. Therefore, folding during the folding test An evaluation based on 10,000 uses only confirms that the product is unusable. Even usable but inadequate products are rated as good, making evaluation impossible. Therefore, To evaluate whether it is at a practical level, the number of folds in the above folding test is small. At the very least, it needs to be evaluated at 100,000 cycles. Also, 10 optical films for every 1 optical film The distance φ between the opposing sides of 0 is 6 mm, and the second functional layer 13 is on the outside, optically. Even when the film 10 is folded 100,000 times, the optical film 10 does not crack or break. It is preferable that it does not occur.

[0050] In the above folding test, the distance φ between opposing sides of the optical film 10 was 6 mm. Although this is done in a manner, from the viewpoint of making the image display device thinner, the opposing sides of the optical film 10 The spacing φ is further narrowed to 4 mm by repeatedly folding 180° 100,000 times. Even when folding tests are performed, it is preferable that no cracks or breaks occur. Furthermore, even if the number of folds is the same, the narrower the above-mentioned interval φ, the more likely it is to crack or It becomes difficult to prevent breakage, so after the folding test with the above spacing φ of 4 mm In the optical film, no cracks or breaks occur, and the above-mentioned spacing φ is 6 mm. Technically, the absence of cracks or breaks in the optical film after testing is technically remarkable. There is a difference.

[0051] When conducting a folding test, first, any part of the optical film 10 before the folding test is... Then cut out a sample S1 of a predetermined size (for example, a rectangular shape of 125mm x 50mm). (See Figure 2(A)). Note that it is not possible to cut the sample to a size of 125mm x 50mm. In this case, it is sufficient if the size allows for the evaluations described later, which are performed after the folding test. For example, You may cut the sample into a rectangle measuring 80mm x 25mm. Before folding test. After cutting out sample S1 from the optical film 10, a folding test was performed on sample S1. Conduct an experiment.

[0052] The folding test is performed as follows. As shown in Figure 2(A), the folding test is performed In this case, first, we take the edge S1a of sample S1 and the edge S1b opposite to edge S1a, Parallel-arranged folding durability testing machines (for example, product name "U-shaped extension testing machine DLDMLH- FS, manufactured by Yuasa System Equipment Co., Ltd., compliant with IEC62715-6-1) fixed part 15 They are fixed to 15 and 16 respectively. The fixing by fixing parts 15 and 16 is in the longitudinal direction of sample S1. This is done by holding a portion of sample S1, approximately 10 mm on each side. However, the sample If the S1 is even smaller than the above size, the portion of the sample S1 required for this fixation If the measurement is up to approximately 20 mm, it can be measured by attaching it to the fixing parts 15 and 16 with tape. Yes (that is, the minimum sample size is 60 mm × 25 mm). Also, as shown in Figure 2(A) As described above, the fixing part 15 is slidable in the horizontal direction. Unlike conventional methods of wrapping samples around a rod, this method generates tension and friction in the sample. It is preferable because it allows for durability evaluation against bending loads without causing any problems.

[0053] Next, as shown in Figure 2(B), with the fixing part 16 fixed, the fixing part 15 and fixing part 1 As the fixing part 15 moves so that 6 is close, the central part S1c of sample S1 is folded. It is deformed in such a way, and further, as shown in Figure 2(C), the fixing parts 15 and 16 of sample S1 The fixing part 1 is moved to a position where the distance φ between the two fixed opposing sides S1a and S1b is 6 mm. After moving part 5, the fixing part 15 is moved in the opposite direction to eliminate the deformation of sample S1.

[0054] As shown in Figures 2(A) to (C), by moving the fixing part 15, the sample S1 can be centered. It can be folded 180° at part S1c. Also, the bending part S1d of sample S1 is fixed part Ensure that it does not protrude from the lower ends of 15 and 16, and perform a folding test under the following conditions, and secure it firmly. By controlling the distance between the fixed part 15 and the fixed part 16 to 6 mm when the fixed part 15 is closest to it, sample S The distance φ between the two opposing sides S1a and S1b of 1 can be made 6 mm. In this case, the bent part S The outer diameter of 1d is assumed to be 6 mm. The thickness of sample S1 is the distance between the fixing parts 15 and 16 ( Since this value is sufficiently small compared to 6mm, the result of the folding test of sample S1 is: It can be assumed that the difference in thickness of sample S1 does not have any effect. (Folding conditions) • Round-trip speed: 80 rpm (cycles per minute) • Test stroke: 60mm • Bending angle: 180°

[0055] When the above folding test is performed on sample S1, cracks appear in sample S1 after the folding test. Alternatively, even if a break does not occur, creases may form in the bent area, and microcracks may develop. This can result in cosmetic defects, specifically clouding and delamination starting from microcracks. Poor adhesion may occur. One of the causes of the clouding phenomenon is one of the optical films. This is thought to be due to a change in the crystalline state of the organic compound that makes up the layer. If this occurs, changes in temperature and humidity can cause moisture to accumulate in the delamination area, or in this delamination area Air can get in, which may increase the cloudiness. In recent years, displays have become more than just flat surfaces. Instead, there is an increasing trend towards diverse 3D designs that can be folded, curved, and so on. Suppressing creases and microcracks in the bent parts is extremely important when used as an image display device. This is important. For this reason, the optical film 10 has flexibility. This is preferable. In this embodiment, "flexibility" means that after the above folding test, Furthermore, not only is there no cracking or breaking, but no creases or microcracks are observed. This means that. Therefore, "flexibility" in this embodiment means the folding described above. Flexibleness that requires only that no cracks or breaks occur after the folding test. These are different things.

[0056] The observation of the creases described above should be done visually, but when observing the creases, use white lighting. In a room (800 lux to 2000 lux), the curved section is evenly exposed to transmitted and reflected light. Observe the inner and outer parts of the bending section when folded. Both conditions shall be observed. The above observation of fold lines shall be performed at a temperature of 23±5℃ and a relative humidity of 30%. The above procedures shall be carried out in an environment with a humidity level of 70% or less.

[0057] The above microcracks are observed using a digital microscope. As for digital microscopes, for example, the VH manufactured by Keyence Corporation. The X-5000 is one example. Microcracks are illuminated by a digital microscope. Ring illumination should be selected, and observations should be made using darkfield and reflected light. Specifically First, the sample after the folding test is slowly unfolded and placed on the microscope stage. Secure the sample with a loop. If the fold is strong, the area to be observed should be as narrow as possible. Make sure it is flat. However, do not touch the area near the center of the sample that is intended for observation (the curved part) with your hand. The force should not be applied too much. And the inner part and the outer part when folded. Observe both of the resulting areas. Observe the above microcracks at a temperature of 23±5℃. Furthermore, the process shall be carried out in an environment with a relative humidity of 30% to 70%.

[0058] In observing the above-mentioned creases and microcracks, the location to be observed is easily grasped. To allow for gripping, the sample before the folding test was placed in the fixed part of the durability testing machine and folded once. When this happens, as shown in Figure 3, the folding direction FD at the bent portion S1d is perpendicular to the bending direction Mark both ends S1d1, located in the direction of the curve, with a permanent marker or similar to indicate that they are bent sections. It is a good idea to do so. Also, in the case of a sample in which no creases or other defects are observed after the folding test, To prevent the observation position of the sample from becoming unclear, it was removed from the durability testing machine after the folding test. In this state, the line M2 (in Figure 3) connects the marks M1 at both ends S1d1 of the bent portion S1d. You may draw a dotted line (or similar) with an oil-based pen. And when observing the crease, bend The region formed by the markers M1 at both ends S1d1 of part S1d and the line M2 connecting these markers M1. The entire bent section S1d is visually inspected. In addition, when observing microcracks, The center of the crossscope field of view (the area enclosed by the dashed line in Figure 3) is at the bent portion S1d. Align the microscope so that it is centered. Note that markings made with an oil-based pen or similar are not used. Care should be taken not to include the markings in the sample area necessary for the actual measurement.

[0059] Furthermore, when the above folding test is performed on sample S1, between the light-transmitting substrate and the first functional layer The adhesion may decrease. Therefore, the bending of the optical film after the above folding test may be affected. In this section, the area near the interface between the light-transmitting substrate 11 and the first functional layer 12 is micronized using a digital microscope. When observed with a co-op, peeling and other issues were observed near the interface between the light-transmitting substrate 11 and the first functional layer 12. It is preferable that this is not done. As for digital microscopes, for example, Keyence Corporation One example is the company-made VHX-5000.

[0060] When an optical film is provided with another film, such as a polarizing plate, via an adhesive or bonding layer. This involves peeling off the adhesive layer and other films together, and then measuring the spectral transmittance, YI, and total light rays. Transmittance, haze value, and pencil hardness shall be measured, and a folding test shall be performed. Other fill The adhesive layer can be removed, for example, as follows: First, the adhesive layer is applied to the optical film. The laminate with other films attached via an adhesive layer is heated with a dryer, and the optical film and other Insert the tip of the cutter blade into what appears to be the interface of the film and slowly peel it off. By repeatedly heating and peeling in this manner, the adhesive layer, bonding layer, and other films are removed. It is possible to do so. However, even if such a peeling process is performed, measuring spectral transmittance, etc. There will be no significant impact.

[0061] Furthermore, as mentioned above, the spectral transmittance, YI, total light transmittance, and haze of the optical film 10 are also important. When measuring the pencil hardness, it is necessary to cut the optical film 10 to the above-mentioned sizes. However, if the optical film 10 is large (for example, in the form of a roll), After cutting out the desired size from the position to A5 size (148mm x 210mm), the size of each measurement item It shall be cut out. For example, if the optical film 10 is in roll form... Then, a predetermined length is unwound from the roll of optical film 10, and the longitudinal direction of the roll Not the ineffective region including both ends that extend along it, but the effective region near the center where the quality is stable. It shall be cut out from the region. Also, the spectral transmittance, YI, and total light transmission of the optical film 10. When measuring the ratio, haze value, and pencil hardness, the above-mentioned device is used for measurement, or optical fiber When performing the folding test of film 10, the above device is used, but other devices are also available. Alternatively, measurements and folding tests may be performed using similar equipment, such as successor models.

[0062] 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, foldable and rollable are used for applications requiring flexibility. That is also preferable.

[0063] 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. For example, optical film 10 If the optical film is in roll form, a predetermined length is taken from the roll of optical film 10. In addition to extending outwards, the product is not an ineffective area including both ends that extend along the longitudinal direction of the roll, but rather... The material will be cut to the desired size from the effective area near the center where the quality is stable.

[0064] <<<Light transparent base material>>> The light-transmitting substrate 11 is a substrate that has light-transmitting properties. The light-transmitting substrate 11 is acetyl acetyl A small amount of lurose resins, cycloolefin polymer resins, and (meth)acrylic resins. It must include at least one of the following. When outdoors, wear sunglasses and use an image display device. Sometimes the displayed image is observed, but if the sunglasses are polarized sunglasses, polarized sunglasses When viewing the displayed image through the glass, rainbow-like discoloration may occur, potentially reducing visibility. This is thought to be because the in-plane phase difference (in-plane retardation, Re) of the light-transmitting substrate is high. Therefore, even when observing the displayed image through polarized sunglasses, It is required that the decrease in visibility be suppressed. In response to this, acetylcellulose-based trees For substrates containing lipids or (meth)acrylic materials, the in-plane phase difference is 10 nm or less. Light-transmitting substrates containing cycloolefin polymer resins include substrates that have not had their phase difference adjusted. For example, there is a substrate whose phase difference has been adjusted to λ / 4, but the phase difference has not been adjusted. The in-plane phase difference of the substrate is 10 nm or less, and even with substrates whose phase difference has been adjusted, the in-plane phase difference The phase difference is 150 nm or less. Therefore, acetylcellulose resin, cycloolefin The light-transmitting substrate 11 containing a polymer resin or a (meth)acrylic resin is a surface Because the internal phase difference is low, the reduction in visibility when viewing the displayed image through polarized sunglasses is suppressed. This is possible. The above in-plane phase difference is the value measured at a wavelength of 589 nm.

[0065] Examples of acetylcellulose resins include triacetylcellulose resins and diacetate. Examples include cellulose-based resins. Triacetylcellulose resins have a visible light range of 380°. This resin is capable of achieving an average light transmittance of 50% or more at ~780nm. The average light transmittance of acetylcellulose resins should be 70% or higher, and preferably 85% or higher. It seems so.

[0066] In addition to pure triacetylcellulose, other types of triacetylcellulose resins are also available. Cellulose acetate propionate, cellulose acetate butyrate, etc. In addition to acetic acid, other components may be used as fatty acids that form esters with the acetic acid. Furthermore, these triacetylcelluloses may contain other types of triacetylcellulose as needed, such as diacetylcellulose. Cellulose lower fatty acid esters may be added.

[0067] Examples of cycloolefin polymer resins include norbornene resins and monocyclic cyclic olefins. Electrolyte resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and their hydrogenation Examples include materials such as: Among these, norbornene resins have transparency and moldability. Because it is of good quality, it can be used suitably.

[0068] Norbornene-based resins include ring-opening polymers of monomers having a norbornene structure or This refers to ring-opening copolymers of monomers having a norbornene structure and other monomers, or their water Addition polymers of monomers having a norbornene structure or monomers having a norbornene structure Examples include addition copolymers of a monomer with another monomer, or hydrides thereof. can.

[0069] Examples of commercially available cycloolefin polymer resins include those manufactured by Nippon Zeon Co., Ltd. Product names "Zeonex (registered trademark)" and "Zeonor (registered trademark)" (norbornene-based resin) ), the product name "Sumilight (registered trademark) FS-1700" manufactured by Sumitomo Bakelite Co., Ltd. JSR Corporation's product name "Arton (registered trademark)" (modified norbornene-based resin), Mitsui Product name "APPEL (registered trademark)" (cyclic olefin copolymer) manufactured by Chemical Co., Ltd., Tico Product name "Topas(registered trademark)" (cyclic olefin copolymer) manufactured by NA Corporation, Hitachi Chemical Co., Ltd. Products such as the "Optrets OZ-1000 series" (alicyclic acrylic resin) manufactured by the company are For example, a light-transmitting substrate can be obtained by forming a film of such a cycloolefin polymer resin. It is possible to produce the film using methods such as solvent casting and melt extrusion. A film-forming method can be used. In addition, the cycloolefin polymer-based film can be formed. The film is also commercially available and can be used as a light-transmitting substrate. Examples of polymer-based films include the product name "SCina" manufactured by Sekisui Chemical Co., Ltd. "Registered Trademark)" and "SCA40", and the product name of Zeon Corporation, "Zeonor Film (Registered Trademark)" Examples include the product name "ARTON® film" manufactured by JSR Corporation.

[0070] Examples of (meth)acrylic resins include poly(meth)acrylate methyl, poly(meth)acrylic acid, and poly(meth)acrylic acid. Ethyl acrylate, methyl methacrylate-butyl methacrylate copolymer These are some examples.

[0071] The thickness of the light-transmitting substrate 11 is not particularly limited, but is preferably 60 μm or less. If the thickness of the light-transmitting substrate 11 is 60 μm or less, further thinning can be achieved. The lower limit of the thickness of the transparent substrate 11 is 5 μm or less, from the viewpoint of ensuring the mechanical strength of the optical film 10. The thickness is preferably 10 μm or more, or more preferably 15 μm or more. The upper limit for thickness is set at 50 μm or less, 45 μm or less, and 40 μm or less, from the perspective of further thinning. It is more preferable that it is 35 μm or less, or 30 μm or less.

[0072] The thickness of the light-transmissive substrate is obtained by photographing a cross-section of the light-transmissive substrate using a scanning electron microscope (SEM), measuring the thickness of the light-transmissive substrate at 10 positions in the image of the cross-section, and obtaining the arithmetic mean value of the thicknesses at those 10 positions. The photographing using a scanning electron microscope is to be performed at a magnification suitable for the thickness of the light-transmissive substrate after clarifying the interface line between the light-transmissive substrate and the functional layer. Specifically, for example, when the thickness of the light-transmissive substrate is 50 μm, the magnification is 1000 times, and when it is 100 μm, the magnification is adjusted appropriately according to the thickness of the light-transmissive substrate, such as 500 times. The variation in the thickness of the light-transmissive substrate 11 is preferably 15% or less, 10% or less, or 7% or less. When measuring the thickness of the light-transmissive substrate using a scanning transmission electron microscope (STEM), it can be measured by the same method as the method for measuring the film thickness of the functional layer. However, the magnification when taking a cross-sectional photograph of the light-transmissive substrate is 100 to 20,000 times. photographing the cross-section of the light-transmissive substrate using a scanning electron microscope (SEM), measuring the thickness of the light-transmissive substrate at 10 positions in the image of the cross-section, and obtaining the arithmetic mean value of the thicknesses at those 10 positions. It can be determined by obtaining the arithmetic mean value of the thicknesses at those 10 positions. When photographing with a scanning electron microscope, it is to be performed at a magnification suitable for the thickness of the light-transmissive substrate after clarifying the interface line between the light-transmissive substrate and the functional layer. Specifically, for example, when the thickness of the light-transmissive substrate is 50 μm, the magnification is 1000 times, and when it is 100 μm, the magnification is adjusted appropriately according to the thickness of the light-transmissive substrate, such as 500 times. The variation in the thickness of the light-transmissive substrate 11 is preferably 15% or less, 10% or less, or 7% or less. When measuring the thickness of the light-transmissive substrate using a scanning transmission electron microscope (STEM), it can be measured by the same method as the method for measuring the film thickness of the functional layer. However, the magnification when taking a cross-sectional photograph of the light-transmissive substrate is 100 to 20,000 times. it can be measured by the same method as the method for measuring the film thickness of the functional layer. However, the magnification when taking a cross-sectional photograph of the light-transmissive substrate is 100 to 20,000 times. it is to be performed at a magnification suitable for the thickness of the light-transmissive substrate after clarifying the interface line between the light-transmissive substrate and the functional layer. Specifically, for example, when the thickness of the light-transmissive substrate is 50 μm,

[0073] When flexibility (for example, foldability) is required for the optical film, if the thickness of the light-transmissive substrate or the functional layer is too thick, there is a risk of cracks occurring in the light-transmissive substrate or the functional layer at the bent portion during folding, and there may also be folding marks or microcracks in the light-transmissive substrate or the functional layer at the bent portion. When cracks, folding marks, or microcracks occur, there is a risk of appearance defects, specifically, clouding phenomena or adhesion failures due to cracks. Therefore, when using the optical film for flexible applications, controlling the thickness of the light-transmissive substrate and the functional layer and the adhesion between each layer (adhesion due to chemical bonds affected by the material and adhesion without cracks occurring) are important. When cracks, folding marks, or microcracks occur, there is a risk of appearance defects, specifically, clouding phenomena or adhesion failures due to cracks. Specifically, there may be clouding phenomena or adhesion failures due to cracks. Therefore, when using the optical film for flexible applications, controlling the thickness of the light-transmissive substrate and the functional layer and the adhesion between each layer (adhesion due to chemical bonds affected by the material and adhesion without cracks occurring) are important. Physical adhesion (such as this) becomes important. In particular, the light-transmitting substrate 11 is acetylcellulose-based When including resins, cycloolefin polymer resins, or (meth)acrylic resins Since the resistance to cracking changes with thickness, controlling the thickness of the light-transmitting substrate is important. When the optical film 10 is folded (bent inward) so that the second functional layer 13 is on the inside, the second unit When the optical film 10 is folded (outward bend) so that the light-transmitting substrate 13 is on the outside, There are 11 different preferred thicknesses.

[0074] (When optical film is used with an inward curve) If the light-transmitting substrate 11 includes, for example, an acetylcellulose resin, then the light-transmitting group The thickness of material 11 is preferably 15 μm or more and 60 μm or less. If it is too thin, the light-transmitting substrate may tear when folded, but this light-transmitting substrate If the thickness of material 11 is 15 μm or more, the light-transmitting substrate 11 will not tear when folded. It can be controlled. Also, if the thickness of the light-transmitting substrate 11 is 60 μm or less, the bending part when folded This can suppress cracking of the light-transmitting substrate 11 and also suppress the whitening phenomenon in the bent portion. In this case, the upper limit of the thickness of the light-transmitting substrate 11 is the cracking of the bending portion when further folded. From the perspective of suppressing clouding, the minimum size should be 45 μm or less, 40 μm or less, 35 μm or less, and especially 30 μm. It is preferable that it is less than or equal to m.

[0075] If the light-transmitting substrate 11 includes, for example, a cycloolefin polymer resin, The thickness of the transmissive substrate 11 is preferably 5 μm or more and 50 μm or less. If the thickness of material 11 is 5 μm or more, the handling properties are good, and if it is 50 μm or less... If present, it can suppress cracking of the light-transmitting base material 11 at the bending portion when folded, and also at the bending portion The clouding phenomenon can be suppressed. In this case, the upper limit of the thickness of the light-transmitting substrate 11 is further folded. From the viewpoint of suppressing the above-mentioned cracking and whitening of the bending part when folded, 45 μm or less, 40 μm or less The particle size is preferably 30 μm or less, or 18 μm or less.

[0076] If the light-transmitting substrate 11 includes, for example, a (meth)acrylic resin, then the light-transmitting substrate The thickness of 11 is preferably 15 μm or more and 50 μm or less. This light-transmitting substrate 11 If the thickness is 15 μm or more, the handling properties are good, and if it is 50 μm or less, This suppresses cracking of the light-transmitting base material 11 at the bending portion when folded, and also at the bending portion This can suppress the clouding phenomenon. In this case, the upper limit of the thickness of the light-transmitting substrate 11 is further folded From the viewpoint of suppressing the cracking and whitening of the bending portion at time, 45 μm or less, 40 μm or less, It is especially preferable that the particle size be 35 μm or less, or 30 μm or less.

[0077] If the thickness of each of the above-mentioned light-transmitting substrates is 35 μm or less, the light-transmitting substrate 11 Applying a protective film improves the processability, which is preferable.

[0078] (When optical film is used with outward bending) The light-transmitting substrate 11 may be, for example, an acetylcellulose resin or a cycloolefin polymer. If it contains a resin system or (meth)acrylic resin, the thickness of the light-transmitting substrate 11 is 1 It is preferable that the thickness is between 0 μm and 50 μm. The thickness of this light-transmitting substrate 11 is 10 μm. If the above conditions are met, it can absorb various impacts from the outside when used on the outside, If it is 50 μm or less, cracking of the light-transmissive substrate 11 at the bent portion during folding can be suppressed, and clouding at the bent portion can also be suppressed. In this case, the upper limit of the thickness of the light-transmissive substrate 11 is preferably 45 μm or less, or 30 μm or less. Also, it is possible to suppress the clouding phenomenon at the bent portion. The upper limit of the thickness of the light-transmissive substrate 11 in this case is preferably 45 μm or less, or 30 μm or less.

[0079] As the light-transmissive substrate 11, from the viewpoint of the adhesion between the light-transmissive substrate 11 and the first functional layer 12, when forming the first functional layer 12, it may be a permeable substrate into which components of the first functional layer 12 (for example, polymerizable compounds) penetrate. However, from the viewpoint of dimensional stability, it is preferable to use a non-permeable substrate into which components of the first functional layer 12 do not penetrate. Examples of the permeable substrate include substrates containing acetyl cellulose-based resins, (meth)acrylic-based resins, etc. Examples of the non-permeable substrate include substrates containing cycloolefin polymer-based resins, etc. When forming the first functional layer 12, components of the first functional layer 12 (for example, polymerizable compounds) may penetrate. However, from the viewpoint of dimensional stability, it is preferable to use a non-permeable substrate into which components of the first functional layer 12 do not penetrate. Examples of the permeable substrate include substrates containing acetyl cellulose-based resins, (meth)acrylic-based resins, etc. Also, examples of the non-permeable substrate include substrates containing cycloolefin polymer-based resins, etc.

[0080] The light-transmissive substrate can be subjected to an etching treatment such as sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, etc. or an undercoating treatment on the surface in advance. By performing these treatments in advance, the adhesion with the functional layer etc. formed on the light-transmissive substrate 11 can be improved. Also, before forming the first functional layer 12 etc., the surface of the light-transmissive substrate 11 may be dust-removed and cleaned by solvent cleaning, ultrasonic cleaning, etc. as necessary. By performing these treatments in advance, the adhesion with the functional layer etc. formed on the light-transmissive substrate 11 can be improved. |>Also, before forming the first functional layer 12 etc., the surface of the light-transmissive substrate 11 may be dust-removed and cleaned by solvent cleaning, ultrasonic cleaning, etc. as necessary. Before forming the first functional layer 12 etc., the surface of the light-transmissive substrate 11 may be dust-removed and cleaned by solvent cleaning, ultrasonic cleaning, etc. as necessary.

[0081] <<<First functional layer>>> [[ID=..36]]The first functional layer 12 serves as an underlayer that improves the adhesion between the light-transmissive substrate 11 and the second functional layer. However, the first functional layer 12 may be a layer having other functions. In particular, when the light-transmissive substrate 11 contains a cycloolefin polymer-based resin, the light-transmissive substrate 11 Since it does not adhere well to the second functional layer 13, the first functional layer 12 is made of a light-transmitting substrate 11 and the second functional layer It is preferable to place it between layers 13. The first functional layer 12 is in close contact with the light-transmitting substrate 11. Furthermore, the first functional layer 12 has light transmittance.

[0082] The thickness of the first functional layer 12 is preferably 0.1 μm or more and 5 μm or less. If the film thickness of the first functional layer 12 is 0.1 μm or more, strong adhesion with the second functional layer 13 is ensured. Yes, it is possible. Furthermore, if the film thickness of the first functional layer 12 is 5 μm or less, the desired pencil hardness can be maintained. Furthermore, it can suppress the occurrence of cracks when bending or curving. The lower limit of the film thickness is 0.3 μm or more and 0.5 μm or more, from the viewpoint of adhesion with the second functional layer 13. Preferably, the thickness of the first functional layer 12 is 0.5 μm or more. This allows for hardness that prevents scratching during the production process. The upper limit, from the perspective of obtaining higher pencil hardness, is 4.5 μm or less, 4 μm or less, or 3 μm. The following is preferable:

[0083] In this embodiment, the "thickness of the first functional layer" refers to the thickness of the first functional layer, which is determined by the contrast difference of the microscope image. The interface line between the permeable substrate and the first functional layer can be recognized, as well as the interface line between the first functional layer and the mixed layer. Since the in can be recognized, it means the distance between these interface lines. The film thickness of the first functional layer is Scanning electron microscope (SEM), transmission electron microscope (TEM), or scanning transmission electron microscope Using STEM or similar methods, a cross-section of the functional layer is captured, and in the image of that cross-section, the first functional layer This can be determined by measuring the film thickness at 10 locations and calculating the arithmetic mean of the film thickness at those 10 locations. It is possible.

[0084] The specific method for taking cross-sectional photographs is as follows: First, take a 1mm x 10mm photograph. A block is prepared by embedding the cut optical film in embedding resin, and this block Then, using a general sectioning method, uniform sections without holes, etc., with a thickness of approximately 70nm to 300nm were prepared. Cut out sections. Sections are prepared using the "Ultramicrotome EM UC7" (Leica Micromicrotome). (Kuro Systems Co., Ltd., etc.) are used. Then, a uniform section without holes, etc., is measured. Let's proceed with the following: Scanning transmission electron microscope (STEM) (product name "S-4800", stock Using a device manufactured by Hitachi High-Technologies Corporation, a cross-sectional photograph of the measurement sample is taken. When taking cross-sectional images using the -4800, set the detector to "TE" and the acceleration voltage to "30k Cross-sectional observation is performed with a voltage of V and an emission current of 10 μA. For magnification, see the four-way scale. Adjust the smudges and observe whether each layer can be distinguished by contrast and brightness, then adjust from 100 to 1 The dilution ratio is 0,000 times, preferably adjusted appropriately between 10,000 and 100,000 times depending on the film thickness of the first functional layer. To reduce measurement variability in film thickness, it is recommended to measure the film thickness of the first functional layer at the lowest possible magnification. For example, if the thickness of the first functional layer is about 1 μm, the magnification is 20,000x, and the thickness is about 0.5 μm. In this case, a magnification of 30,000 to 100,000 times is preferable. Furthermore, set condenser lens 1 to "5.0". And, set the WD to "8.9mm".

[0085] The indentation hardness of the first functional layer 12 is between 50 MPa and 600 MPa. Preferably, the indentation hardness of the first functional layer 12 is 50 MPa or more. This allows for obtaining the desired pencil hardness while suppressing a decrease in scratch resistance. If the indentation hardness of functional layer 12 is 600 MPa or less, good flexibility can be obtained. This allows for the suppression of crack formation during chip cutting. "Indentation stiffness" is determined from the load-displacement curve of the indenter from loading to unloading. This is the value. However, in layers that are too soft, such as adhesive layers, the indentation Even when attempting to measure the hardness, measurement may be impossible. The lower limit of the hardness of the pencil is set at 7, from the viewpoint of obtaining higher pencil hardness and good scratch resistance. The pressure must be 0 MPa or higher, 85 MPa or higher, 100 MPa or higher, or 150 MPa or higher. This is more preferable. Also, the upper limit of the indentation hardness of the first functional layer 12 is excellent flexibility. In order to achieve performance and further suppress crack occurrence during chip cutting, 500 MPa The following are more likely: 450 MPa or less, 400 MPa or less, or 350 MPa or less. preferable.

[0086] Indentation hardness (H IT ) is a TI manufactured by HYSITRON. This can be measured using the 950 TriboIndenter. Specifically, first A block is created by embedding optical film cut to 1mm x 10mm in embedding resin. Prepare a sample suitable for hardness measurement using the nanoindentation method. For sample preparation, the "Ultramicrotome EM UC7" (Leica Microsys) is used. Thames Corporation, etc. can be used. Next, the surface on which the indenter of the measurement sample is pressed is The measurement sample is positioned parallel to the mounting surface of the stage using HYSITRON. It is fixed to the stage of the company's TI950 TriboIndenter. And the first unit At the flat portion at the center of the cross-section of the energy layer, using a load control method, the maximum pushing-in load is 300 μN In this way, push a Berkovich indenter into the first functional layer at a load rate of 10 μN / second from a load of 0 μN to 300 μN in 30 seconds while applying the load. Here, in order to avoid the influence of the side edges of the first functional layer, at least 500 n m away from both side ends of the first functional layer towards the center side of the first functional layer, push the Berkovich indenter into the portion of the first functional layer. Then, after holding at 300 μN for 5 seconds, unload from 300 μN to 0 μN in 30 seconds. And continuously measure the pushing-in depth h (nm) corresponding to the pushing-in load F (N) at this time, and create a load- displacement curve. The indentation hardness H can be obtained by dividing the maximum pushing-in load F (N) by the projected area A IT as shown in the following formula (2) when the indenter and the first functional layer are in contact . The indentation max hardness is the arithmetic mean value of the values obtained by measuring at 10 locations. Also, the measurement of the indentation hardness is carried out in an environment with a temperature of 23 ± 5 °C and a relative humidity of 30% or more and 70% or less p (mm 2 ). H = F / A ...(2) IT Here, A max is a value obtained by the following formula (3). p A = 23.96 (h p - 0.75 (h[[ID=)46]] A p = 23.96 (h [[ID=)50]] max - 0.75 (h [[ID=)52]] max - h [[ID=)54]] r )) 2 ...(3) In the above formula (3), h max is the maximum pushing-in depth, and h r is the unloading at F max The tangent line to the curve is the value at the intersection with the horizontal axis (displacement).

[0087] The first functional layer 12 contains a resin and an ultraviolet absorber. The ultraviolet absorber is the first It is sufficient that it is included in either the first functional layer 12 or the second functional layer 13, and in the first functional layer 12 It is not necessarily required to include. The first functional layer 12 contains, in addition to the resin and UV absorber, It may contain polymerization initiators and their residues.

[0088] <<Resin>> The resin included in the first functional layer 12 includes polymers (cured products) of polymerizable compounds. The resin includes polymers of polymerizable compounds, as well as solvent-drying resins and thermosetting compounds. It's okay to be there.

[0089] (polymerizable compound) A polymerizable compound has at least one polymerizable functional group. A "polymerizable functional group" is a functional group that can undergo polymerization reactions. Examples of polymerizable functional groups include, for example... Examples include ethylenically unsaturated groups such as (meth)acryloyl groups, vinyl groups, and allyl groups. In this specification, "(meth)acryloyl group" refers to "acryloyl group" or "meth It means "containing a cryl group." Also, ionizing radiation is used when polymerizing polymerizable compounds. Examples of radiation include visible light, ultraviolet rays, X-rays, electron beams, alpha rays, beta rays, and gamma rays. .

[0090] Polymerizable compounds having one ethylenically unsaturated group include, for example, ethyl(meth)acrylate. Relate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinyl Examples include lupyrolidone, a polymerizable compound having two or more ethylenically unsaturated groups. Examples include polymethylolpropane tri(meth)acrylate and hexanediol. Dimethyl(meth)acrylate, tripropylene glycol dimethyl(meth)acrylate, diethyl Glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate , dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di( Polyfunctional compounds such as meth)acrylate and neopentyl glycol di(meth)acrylate , or a reaction product (e.g., polyhydric alcohol) of the above polyfunctional compound with (meth)acrylates, etc. Examples include poly(meth)acrylate esters.

[0091] Polymerizable compounds include polymerizable monomers, polymerizable oligomers, and / or polymerizable polymers. The polymer can be prepared and used as appropriate.

[0092] (Solvent-drying resin) Solvent-drying resins, such as thermoplastic resins, use solvents added to adjust the solid content during coating. This is a resin that forms a film simply by drying. By using a solvent-drying resin in combination... This effectively prevents defects in the coating on the applied surface. It is used in combination with the polymerizable compound mentioned above. The solvent-drying resins that can be used are not particularly limited, and generally thermoplastic resins can be used. It is possible.

[0093] The thermoplastic resins mentioned above are not particularly limited, and include, for example, styrene resins and (meth)acrylic resins. Vinyl resins, vinyl acetate resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins Polyvinyl resins, polycarbonate resins, polyester resins, polyamide resins, cellulose Examples include silicone derivatives, silicone resins, or silicone rubbers.

[0094] The above thermoplastic resin is amorphous and contains organic solvents (especially multiple polymers and polymerizable compounds). It is preferable that it is soluble in a common solvent capable of dissolving it. In particular, film-forming properties, transparency and weather resistance From this perspective, styrene resins, (meth)acrylic resins, alicyclic olefin resins, polyethylene Sterl-based resins and cellulose derivatives (such as cellulose esters) are preferred.

[0095] (thermosetting compound) The thermosetting compound is not particularly limited and includes, for example, phenolic resins, urea resins, and diamine resins. Rylphthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, poly Urethane resin, epoxy resin, aminoalkyd resin, melamine-urea cocondensate resin, silicon Examples include resins and polysiloxane resins.

[0096] <UV absorber> UV absorbers are those that absorb at least ultraviolet light (wavelengths of 10nm to 400nm). UV absorbers, as long as they absorb ultraviolet light, have their maximum absorption wavelength in the visible light range. It may be present. In the case of UV absorbers, within the wavelength range of 360 nm to 430 nm The maximum absorbance is preferably 0.5 or higher. Examples of UV absorbers include Inzotriazole compounds, indole compounds, benzophenone compounds, triazines Examples include compound systems, etc. Among these, from the viewpoint of suppressing the reduction in visibility due to coloring, Benzotriazole compounds and indole compounds are preferred.

[0097] To determine whether the first functional layer 12 contains an ultraviolet absorber, first, a fragment of the first functional layer 12 is taken. Then, the fragment was measured by infrared spectroscopy (IR), and the obtained infrared absorption spectrum was... This can be investigated by comparing it with commercially available UV absorbers. The UV absorber is the first... It may also be included as a copolymer in the resin constituting the functional layer 12.

[0098] Examples of benzotriazole compounds include sesamol represented by the following general formula (A). Benzotriazole monomers of type 2, 2-[2-hydroxy-3,5-bis(α,α-dimethicone] Rubenzyl)phenyl]-2H-benzotriazole (product name "Tinuvin234") (Manufactured by BASF), 2-(5-chloro-2-benzotriazolyl)-6-tert-buty Examples include ru-p-cresol (product name "Tinuvin326", manufactured by BASF). Among these, those with a steeper spectral slope that absorb ultraviolet light more selectively... Since this is possible, the sesamol-type benzotriazole monomolar represented by the following general formula (A) The body is desirable. [ka] In the formula, R 1 R represents a hydrogen atom or a methyl group. 2 These are linear or branched chains with 1 to 6 carbon atoms. Chain-like alkylene groups, or linear or branched oxyalkylenes having 1 to 6 carbon atoms. It represents the basis.

[0099] The sesamol-type benzotriazole monomer represented by the above general formula (A) is the first functional layer It is contained as a monomer unit in the resin that makes up 12. It is also represented by the above general formula (A). Sesamol-type benzotriazole monomers have a nitrogen atom at position 2 of the benzotriazole ring. It is a derivative of a compound to which sesamol is bonded, and the benzene ring of the benzotriazole ring It has a molecular structure in which a polymerizable double bond is introduced at the position. This monomer has a maximum absorption wavelength λ max It is above 365 nm, encompassing a broad range of wavelengths from 300 nm to 400 nm. It has a wide ultraviolet absorption spectrum and possesses ultraviolet absorption capability up to the long wavelength range around 400 nm. ru.

[0100] The above sesamol-type benzotriazole monomer is not particularly limited, but The substance's name is 2-[2-(6-hydroxybenzo[1,3]dioxol-5-yl] )-2H-benzotriazol-5-yl]ethyl methacrylate, 2-[2-(6-H] Droxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole-5- [Iyl]ethyl acrylate, 3-[2-(6-hydroxybenzo[1,3]dioxol -5-yl)-2H-benzotriazole-5-yl]propyl methacrylate, 3-[ 2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotria Zole-5-yl]propyl acrylate, 4-[2-(6-hydroxybenzo[1,3 ]Dioxol-5-yl)-2H-benzotriazole-5-yl]butylmethacrylate 4-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H- [benzotriazol-5-yl]butyl acrylate, 2-[2-(6-hydroxyben Zo[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 [Riazole-5-yl]propanoyloxy]ethyl methacrylate, 2-[3-{2-( 6-Hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole -5-yl}propanoyloxy]ethyl acrylate, 4-[3-{2-(6-hydroxyl Cibenzo[1,3]dioxol-5-yl)-2H-benzotriazole-5-yl} Propanoyloxy]butyl methacrylate, 4-[3-{2-(6-hydroxybenzo] [1,3] Dioxol-5-yl)-2H-benzotriazole-5-yl}propano Iloxy]butyl acrylate, 2-[3-{2-(6-hydroxybenzo[1,3] Dioxol-5-yl)-2H-benzotriazole-5-yl}propanoyl oxy ]Ethyl methacrylate, 2-[3-{2-(6-hydroxybenzo[1,3]dioxo (Il-5-yl)-2H-benzotriazol-5-yl}propanoyloxy]ethyl Acrylate, 2-(methacryloyloxy)ethyl 2-(6-hydroxybenzo[1, 3] Dioxol-5-yl)-2H-benzotriazole-5 carboxylate, 2- (Acryloyloxy)ethyl 2-(6-hydroxybenzo[1,3]dioxol-5) -yl)-2H-benzotriazole-5-carboxylate, 4-(methacryloyl) Xy)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 -5-carboxylates. In addition, these sesamol-type benzotriols can be cited. Azole monomers can be used individually or in combination of two or more types.

[0101] (Indole compounds) Examples of indole compounds include those represented by the following general formula (B). If the compound is represented by the general formula (B) below, then the wavelength is between 380 nm and 400 nm. It can absorb light in a specific wavelength range. [ka] In formula (B), R 3 This represents a linear or branched alkyl or aralkyl group. R 4 -CN or -COOR 5 This represents, where R 5 It may have substituents. Alkyl or aralkyl group (however, R 3 If it is a methyl group, remove the ethyl group. ) represents.

[0102] R 3 The number of carbon atoms can be between 1 and 12. 3 A concrete example of this is, Iol group, ethyl group, (iso)butyl group, t-butyl group, hexyl group, octyl group, 2-ethyl group Examples include tylhexyl group, dodecyl group, benzyl group, etc. 5 For example, If the above R 3 The groups exemplified above, as well as β-cyanoethyl group, β-chloroethyl group, and ethoxypropyl Examples include pyr groups, hydroxyalkyl groups, and alkoxyalkyl groups. However, R 3 ga Me If it is a chill group, R 5 It is not an ethyl group.

[0103] As an example of an indole compound, BONASORB U, manufactured by Orient Chemical Industries, Ltd. Examples include the A-3911.

[0104] The above-mentioned UV absorber is, for example, present in the first functional layer 12 in an amount of 0.05% to 50% by mass. It may also be contained in such a range. It can effectively absorb rays. Furthermore, the above UV absorber is sesamol-type benzotrione. In the case of a zole compound, it is present in the first functional layer 12 in an amount of 0.1% by mass or more and 50% by mass or less. It may contain it.

[0105] The first functional layer 12 is, for example, a composition for the first functional layer that includes a polymerizable compound and an ultraviolet absorber. It can be formed by using a material. The composition for the first functional layer is polymerizable as described above. It contains compounds, etc., but also, as necessary, polymerization initiators, solvents, leveling agents, etc. That's fine.

[0106] (Polymerization initiator) The polymerization initiator is not particularly limited and known ones can be used. One type may be used, but two or more types may also be used. Specific examples of polymerization initiators include: For example, acetophenones, benzophenones, michler-benzoylbenzoates, α - Amyloxime esters, thioxanthones, propiophenones, benzyl compounds, benzo Examples include ions and acylphosphine oxides. Furthermore, photosensitizers can be used in combination. It is preferable that the material be n-butylamine, triethylamine, and por Examples include re-n-butylphosphine.

[0107] As a polymerization initiator, if the polymerizable compound has a radical polymerizable functional group, acetamide is used. Tophenones, benzophenones, thioxanthones, benzoin, benzoin methyl esters It is preferable to use radical polymerization initiators such as ether alone or in combination. Among the initiators, 2,4,6-tri is chosen because it suppresses curing inhibition due to UV absorption performance. Methylbenzoyl diphenylphosphine oxide (e.g., IGM Resins B.) Omnirad TPO (manufactured by V. Company), bis(2,4,6-trimethylbenzoyl) Nylphosphine oxide (for example, Omnira from IGM Resins BV) d819), 1-hydroxycyclohexylphenyl ketone (e.g., IGM Resi Omnirad184 manufactured by ns BV, oligo(2-hydroxy-2-methyl- 1-(4-(1-methylvinyl)phenyl)propanone) (ES manufactured by DKSH Japan) ACURE ONE) or mixtures thereof are more preferable.

[0108] Furthermore, if the polymerizable compound has a cationic polymerizable functional group, the polymerization initiator is Aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metallocene salts Cationic polymerization initiators such as compounds and benzoin sulfonate esters, either alone or in mixtures It is preferable to use it. Among cationic polymerization initiators, aromatic polymers are preferred due to their excellent curing properties. A ruphonium salt is more preferable.

[0109] Furthermore, if the light-transmitting substrate 11 contains a cycloolefin polymer resin, It is important to ensure that the first functional layer 12 is in close contact with the light-transmitting substrate 11. In order to adhere 12 to the light-transmitting substrate 11, an oxime ester system is used as the polymerization initiator. It is preferable to use a compound. Examples of commercially available oxime ester compounds include, RGACURE(registered trademark) OXE01, IRGACURE(registered trademark) OXE02, I Examples include RGACURE® OXE03 (both manufactured by BASF Japan). .

[0110] The content of the polymerization initiator in the composition for the first functional layer is 100% by mass of the polymerizable compound. The amount is preferably 1 part by mass or more and 10 parts by mass or less per part. Content of the polymerization initiator If the amount is 1 part by mass or more, the hardness of the first functional layer will be sufficient, and if it is 10 parts by mass or less Because the ionizing radiation reaches deep into the coating, internal hardening is promoted, and the target optical film is achieved. The surface hardness of the material (for example, 3B or higher on the pencil hardness scale, as described later) can be obtained.

[0111] The lower limit of the content of the polymerization initiator is more preferably 2 parts by mass or more, and the upper limit is 8 parts by mass. It is more preferable that the amount is less than or equal to parts per 100%. This prevents a hardness distribution from occurring in the film thickness direction, resulting in a more uniform hardness.

[0112] (solvent) The solvent should be selected and used according to the type and solubility of the polymerizable compound used. This can be done, for example, with ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone) , cyclohexanone, diacetone alcohol, etc.), ethers (dioxane, tetrahydroxane) Lofran, propylene glycol monomethyl ether, propylene glycol monomethyl Ether acetates, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclo Hexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated carbons (diclorous hydrocarbons) (e.g., molethane, dichloroethane), esters (e.g., methyl acetate, ethyl acetate, butyl acetate) Water, alcohols (ethanol, isopropanol, butanol, cyclohexanol) (etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetate Sulfoxides (dimethyl sulfoxide, etc.), amides (dimethylformamide, di) Examples include methylacetamide, etc., and mixed solvents thereof may also be used.

[0113] (Leveling agent) The leveling agent is not particularly limited, but a fluorine-based leveling agent is preferred. By using a leveling agent, high leveling properties are achieved, resulting in smoothness and recoatability. It can be provided. Examples of commercially available fluorine-based leveling agents include F-555 (DIC Corporation). (Manufactured by [Company Name]), F-568 (Manufactured by DIC Corporation), F-568 (Registered Trademark) 683 (Company Name) (Manufactured by Neos Co., Ltd.) is one example.

[0114] The proportion of raw materials (solid content) in the composition for the first functional layer is not particularly limited, Preferably, the concentration is 5% by mass or more and 70% by mass or less, and more preferably 15% by mass or more and 60% by mass or less. .

[0115] The method for preparing the composition for the first functional layer is not particularly limited as long as each component can be mixed uniformly. For example, using known devices such as paint shakers, bead mills, kneaders, and mixers. It can be done by doing so.

[0116] The method for applying the composition for the first functional layer onto the light-transmitting substrate 11 is not particularly limited, for example, For example, spin coating, dip coating, spray coating, die coating, bar coating, roll coating. Coater method, meniscus coater method, flexographic printing method, screen printing method, speed coater Examples include publicly known methods such as laws and regulations.

[0117] The ionizing radiation source used for curing the composition for the first functional layer is mainly 190-450 ohms. Preferably, the emission peak is in the wavelength range of m. As an ionizing radiation source, for example, ultra-high Pressurized mercury lamps, high-pressure mercury lamps, low-pressure mercury lamps, carbon arc lamps, black light fluorescent lamps, metal Examples of light sources include halide lamps.

[0118] <<Second functional layer>> The second functional layer 13 is a hard coat layer. However, the second functional layer 13 is made of other materials. It may also be a layer having properties. In this embodiment, the "hard coat layer" refers to an indentation layer This refers to a layer whose indentation hardness is greater than that of the first functional layer. The indentation stiffness of the functional layer is also determined in the same way as the indentation stiffness of the first functional layer. ru.

[0119] The indentation hardness of the second functional layer 13 is between 75 MPa and 1000 MPa. It is preferable that the indentation hardness of the second functional layer 13 is 75 MPa or higher. If the desired pencil hardness is obtained, and if the pressure is below 1000 MPa, crack formation will not occur. This can be suppressed. The lower limit of the indentation hardness of the second functional layer 13 is higher than the pencil hardness. From the perspective of obtaining this, the pressure should be 100 MPa or higher, 150 MPa or higher, or 200 MPa or higher. This is more preferable. Also, the upper limit of the indentation hardness of the second functional layer 13 is the crack From the perspective of further suppressing occurrence, the pressures should be 900 MPa or less, 750 MPa or less, and 600 MPa or less. or more preferably 500 MPa or less. Indentation of the second functional layer 13 If the hardness is 600 MPa or less, a second functional layer 13 with excellent flexibility can be obtained. ru.

[0120] The thickness of the second functional layer 13 is preferably 0.1 μm or more and 9.8 μm or less. If the film thickness of the functional layer 13 is 0.1 μm or more, the desired pencil hardness can be ensured, and the second function If the thickness of layer 13 is 9.8 μm or less, it is possible to make it even thinner and fold it. It can suppress the occurrence of cracks during bending and flexing. The lower limit of the film thickness of the second functional layer 13 is From the perspective of obtaining the highest possible pencil hardness, the thickness should be 0.3 μm or more, 0.5 μm or more, or 1 μm or more. It is preferable that the thickness of the second functional layer 13 is 0.5 μm or more, which prevents scratches in the production process. A high level that prevents adhesion can be obtained. The upper limit of the film thickness of the second functional layer 13 can be further thinned. From the perspective of achieving this, the size should be 8 μm or less, 5 μm or less, 4 μm or less, or 3 μm or less. Preferably, the film thickness of the second functional layer 13 can be determined by the same method as for the first functional layer 12. can.

[0121] The second functional layer 13 contains a resin and an ultraviolet absorber. However, the first functional layer 12 is If it contains a UV absorber, it does not need to contain a UV absorber. Second functional layer 13 Furthermore, when the optical film 10 is wound into a roll shape, the optical film 10 adheres to each other. It may also contain an anti-blocking agent to prevent blockage. It is included in the second functional layer 13. The resin contains polymers of polymerizable compounds. In addition, it may also contain solvent-drying resins or thermosetting compounds.

[0122] The concentration of the UV absorber in the second functional layer 13 is equal to the concentration of the UV absorber in the first functional layer 12. It is preferable that the concentration of the ultraviolet absorber in the second functional layer 13 is lower than that of the first functional layer 13. The concentration of the UV absorber in layer 12 is lower than the concentration of the UV absorber, thus preventing the UV absorber from bleeding out. This can reduce the amount of abrasion and further improve the scratch resistance of the surface of the second functional layer 13.

[0123] The polymerizable compounds constituting the second functional layer 13 include polymerizable monomers and polymerizable oligomers. Examples include polymerizable prepolymers, which can be appropriately adjusted and used. Polymerizable compounds include polymerizable monomers and polymerizable oligomers or polymerizable prepolymers. A combination with this is preferable.

[0124] Examples of polymerizable monomers include 2-hydroxyethyl (meth)acrylate, 2- Hydroxypropyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. monomers containing hydroxyl groups, ethylene glycol di(meth)acrylate, diethylene glycol Licor di(meth)acrylate, triethylene glycol di(meth)acrylate, te Traethylene glycol di(meth)acrylate, tetramethylene glycol di(meth) Acrylate, trimethylolpropane, tri(meth)acrylate, trimethylolethanol Pentaerythritol (meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol Lythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate Dipentaerythritol tetra(meth)acrylate, dipentaerythritol (Meth)acrylic acids such as xa(meth)acrylate and glycerol(meth)acrylate Esters are one example.

[0125] As polymerizable oligomers, polyfunctional oligomers with two or more functions are preferred, and polymerizable functional groups A polyfunctional oligomer with three or more (trifunctional) properties is preferred. Examples of the above polyfunctional oligomers include: For example, polyester (meth)acrylate, urethane (meth)acrylate, polyester Tel-urethane (meth)acrylate, polyether (meth)acrylate, polyol (meth)acrylate, melamine (meth)acrylate, isocyanurate (meth)acrylate Examples include relates and epoxy (meth)acrylates.

[0126] Polymerizable prepolymers have a weight-average molecular weight exceeding 10,000, and A weight-average molecular weight of 10,000 to 80,000 is preferred, and a weight-average molecular weight of 10,000 to 40,000 is more preferred. If the viscosity exceeds 80,000, the coating suitability will decrease due to the high viscosity, and the resulting light-transmitting resin The appearance of the fat may deteriorate. As a polyfunctional prepolymer, urethane (meth)acrylate Relate, isocyanurate (meth)acrylate, polyester-urethane (meth)acrylate Examples include acrylates and epoxy (meth)acrylates.

[0127] <UV absorber> The UV absorber is the same UV absorber as described in section 12 of the first functional layer. Since it can be used, we will omit the explanation here.

[0128] The second functional layer 13 is formed by using a composition for the second functional layer that includes polymerizable compounds, etc. It is possible to achieve this. The composition for the second functional layer contains polymerizable compounds and ultraviolet absorbers, in addition to It may also contain solvent-drying resins, thermosetting compounds, polymerization initiators, solvents, etc. The two-functional layer composition may, if necessary, contain the following various additives, to the extent that they do not impair the effects of the present invention. It may contain an agent. Examples of such additives include inorganic particles, antistatic agents, and adhesives. Adhesion improvers, leveling agents, thixotropic agents, coupling agents, plasticizers, defoamers, fillers Examples include colorants, etc.

[0129] The composition for the second functional layer consists of a solvent-drying resin, a thermosetting compound, a polymerization initiator, a solvent, and a leveling agent. The coating agents, etc., are solvent-drying resins, thermosetting compounds, and polymers as described in the composition for the first functional layer above. Since it is similar to initiators, solvents, leveling agents, etc., we will omit the explanation here.

[0130] The polymerization initiator in the composition for the second functional layer is the same as the polymerization initiator in the composition for the first functional layer. It may be, but it is preferable that it be different. Polymerization initiation in the composition for the second functional layer By using a different agent than the polymerization initiator in the composition for the first functional layer, the composition for the first functional layer For the finished product, a polymerization initiator that is easy to partially cure was selected, and for the composition for the second functional layer, the surface A polymerization initiator with good surface hardening properties can be selected.

[0131] <<Mixed layer>> The mixed layer 14 contains the components of the first functional layer 12 and the components of the second functional layer 13, and the first functional layer 12 and adjacent to the second functional layer 13. By forming such a mixed layer 14, The adhesion between the first functional layer 12 and the second functional layer 13 can be improved. The mixed layer 14 Whether or not it contains the components of the first functional layer 12 and the components of the second functional layer 13 depends on the time-of-flight type secondary ionic substance. This can be confirmed by quantitative analysis (TOF-SIMS).

[0132] The mixed layer 14 contains the components of the first functional layer 12 and the components of the second functional layer 13, and the first functional layer 1 The method for forming the mixed layer 14 is not particularly limited, as long as it is a layer adjacent to the second functional layer 13. No. For example, the mixed layer 14 has the components of the first functional layer 12 and the second functional layer on the surface of the first functional layer 12. It may also be formed by applying a composition containing the components of layer 13, or by using a first functional layer assembly. The second functional layer composition is applied to the surface of the coating film of the finished product while it is still semi-cured. Therefore, it may be formed. However, in order to further improve adhesion and make it thinner, With the coating film of the first functional layer composition semi-cured, the second functional layer composition is applied to the surface of this coating film. It is preferable to form it by applying the first functional layer composition. With the first coating film 21 partially cured, the composition for the second functional layer is applied to the surface of the first coating film 21. When a mixed layer is formed by doing so, the reason is unclear, but the composition for the second functional layer The solvent penetrates the semi-cured coating film, and the polymerizable compound components also penetrate the semi-cured coating film. It is thought that the material is drawn into the membrane, forming a mixed layer.

[0133] The concentration of the component of the second functional layer 13 in the mixed layer 14 is from the second functional layer 13 to the first functional layer 12. It is preferable that the concentration gradually decreases toward the goal. The mixed layer 14 has such a concentration gradient. This ensures strong adhesion between the first functional layer 12 and the second functional layer 13. Such concentration gradients can be confirmed by TOF-SIMS. The mixed layer 14 having a degree distribution is in a state where the coating film of the first functional layer composition has been semi-cured, and this coating film It can be formed by applying a composition for the second functional layer to the surface.

[0134] The film thickness of the mixed layer 14 relative to the total film thickness of the first functional layer 12, the second functional layer 13, and the mixed layer 14 Thickness ratio (film thickness of mixed layer 14 / (film thickness of first functional layer 12 + film thickness of second functional layer 13 + mixed layer) The ratio of film thickness (14) × 100 is preferably 0.6% or more and 40% or less. If the concentration is 0.6% or higher, the adhesion (initial adhesion) before the durability test will be good. On the other hand, the mixture Since the layer is relatively soft, if the above ratio is too large, the optical film will become too soft. There is a risk of this occurring. If the above percentage is 40% or less, the surface hardness of the optical film 10 will decrease. It can be suppressed. The lower limit of the above ratio improves not only the initial adhesion but also the adhesion after the durability test. From this perspective, it is preferable that the amount be 1% or more, 3% or more, 5% or more, or 10% or more. The upper limit of the film thickness for the above percentages is 35% or less, 30% or less, or 20% or less, from the perspective of thinning. It is preferable that it be lower.

[0135] The thickness of the mixed layer 14 is preferably 0.02 μm or more and 3 μm or less. If the film thickness is 0.02 μm or more, the initial adhesion will be good, and if it is 3 μm or less, This suppresses the decrease in surface hardness of the optical film 10. The thicker the mixed layer 14, the denser it becomes. Since adhesion is improved, the lower limit of the film thickness of the mixed layer 14 is determined not only by the initial adhesion but also after the durability test. From the perspective of improving adhesion, the thickness should be 0.1 μm or more, 0.2 μm or more, or 0.4 μm or more. Preferably, the upper limit of the film thickness of the mixed layer 14 is such that the surface hardness of the optical film 10 decreases. From the viewpoint of suppressing [something], it is more preferable that the thickness be 2 μm or less or 1 μm or less. Mixed layer 1 The film thickness of 4 can be adjusted by adjusting the degree of semi-curing of the first functional layer 12. In other words, if the degree of semi-curing of the first functional layer 12 is reduced, the film thickness of the mixed layer 14 will be large. If the degree of semi-hardening is increased, the film thickness of the mixed layer 14 will decrease.

[0136] <<Manufacturing method for optical film>> The optical film 10 can be manufactured, for example, as follows. First, Figure 4( As shown in A), the composition for the first functional layer is applied to one surface 11A of the light-transmitting substrate 11. The first coating film 21 is formed by applying and drying the coating. Then, as shown in Figure 4(B) Next, the first coating film 21 is irradiated with ionizing radiation such as ultraviolet light to polymerize (crosslink) polymerizable compounds. This causes the first coating film 21 to partially harden. In this specification, "partially hardened" refers to the ionizing radiation Further irradiation with the laser means that the hardening process will effectively progress.

[0137] After the first coating 21 has partially cured, the composition for the second functional layer is applied to the surface of the first coating 21. When dried, as shown in Figure 5(A), in addition to the second coating 22, the first coating 21 and the second A mixed coating 23 containing the components of the first coating 21 and the components of the second coating 22 is formed between the coating films 22. ru.

[0138] Next, as shown in Figure 5(B), the first coating 21, the second coating 22, and the mixed coating 2 By irradiating the polymerizable compound with ionizing radiation such as ultraviolet light, the polymerizable compound is polymerized (crosslinked), thereby producing the third The first coating film 21, the second coating film 22, and the mixed coating film 23 are cured (for example, completely cured). In the detailed document, "complete hardening" means that further irradiation with ionizing radiation will not substantially advance the hardening process. This means that the first functional layer 12, the second functional layer 13, and the first functional layer A mixed layer 14 is formed between 12 and the second functional layer 13, so an optical film 10 is obtained. .

[0139] According to this embodiment, the total film thickness of the first functional layer 12, the second functional layer 13, and the mixed layer 14 is Since it is between 1 μm and 10 μm, it can be made thinner. Also, the first functional layer 1 When at least one of 2 and the second functional layer 13 contains an ultraviolet absorber, Between functional layer 12 and second functional layer 13, adjacent to the first functional layer 12 and second functional layer 13, The film of the mixed layer 14 relative to the total film thickness of the first functional layer 12, the second functional layer 13, and the mixed layer 14 Since a mixed layer 14 with a thickness ratio of 0.6% to 40% is formed, the surface hardness is low. This suppresses downward movement and improves the adhesion between the first functional layer 12 and the second functional layer 13. It is possible.

[0140] According to this embodiment, at least one of the first functional layer 12 and the second functional layer 13 is purple When an external radiation absorbent is included, between the first functional layer 12 and the second functional layer 13, the first functional layer 1 A mixed layer adjacent to 2 and the second functional layer 13, with a film thickness of 0.02 μm or more and 1 μm or less. Since 14 is formed, the decrease in surface hardness can be suppressed, and the first functional layer 12 and the second This can improve the adhesion between the functional layers 13.

[0141] According to this embodiment, the light-transmitting substrate 11 is an acetylcellulose resin, cycloolefin Since it contains a polymer-based resin or a (meth)acrylic resin, it is a light-transmitting substrate 1 The in-plane phase difference Re of 1 is at most about 150 nm. Therefore, when viewed through polarized sunglasses... This can suppress the decrease in visibility when viewing the displayed image.

[0142] <<<Polarizing plate>>> The optical film 10 can be incorporated into a polarizing plate for use. Figure 6 shows the actual implementation. This is a schematic diagram of the polarizing plate relating to its form. As shown in Figure 6, the polarizing plate 30 is an optical filter The film 10, polarizer 31, and protective film 32 are provided in this order. In case 0, the polarizer 31 is provided on the light-transmitting substrate 11 side of the optical film 10. A polarizer may be provided on the functional layer side of the optical film.

[0143] The optical film 10 and the polarizer 31, and the polarizer 31 and the protective film 32 are, for example, water They are bonded together with a fluoropolymer adhesive or a UV-curing adhesive.

[0144] <<Polarizer>> The polarizer 31 is provided on the side of the light-transmitting substrate 11 opposite to the side facing the first functional layer 12. The polarizer 31 is stained with iodine or a dichroic dye and uniaxially stretched. Examples include polyvinyl alcohol-based resin films. In this case, a saponified polyvinyl acetate resin can be used. As for lipids, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, vinyl acetate and its compounds Examples include copolymers with other polymerizable monomers. Examples of such substances include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated carboxylates. Examples include ammonium acids and acrylamides having an ammonium group. Coal-based resins may be modified, for example, polyvinyl vinyl modified with aldehydes. Formal or polyvinyl acetal can also be used.

[0145] <<Protective film>> Examples of protective films 32 include triacetylcellulose-based films and (meth)a Examples include acrylic resin films and cycloolefin polymer films.

[0146] <<<Image display device>>> The optical film 10 or polarizing plate 30 can be incorporated into an image display device for use. Figure 7 is a schematic diagram of the image display device according to this embodiment. The image display device 40 is oriented towards the observer and includes a display element 50, a circular polarizing plate 60, and a touch sensor. The components 70 and the cover member 80 are provided in this order. Between the display element 50 and the circular polarizing plate 60, the circle The polarizing plate 60 and the touch sensor 70, and the touch sensor 70 and the cover member 80 are bonded together. They are bonded via layers 91-93. In this specification, "bonding" includes the concept of tackiness. be.

[0147] <<<Display element>>> The display element 50 includes liquid crystal elements and organic light-emitting diode elements (hereinafter referred to as "OLED elements"). It is sometimes referred to as such. ) Inorganic light-emitting diode elements, micro-LEDs, plasma elements, etc. For example, known organic light-emitting diode elements can be used. It is possible. In addition, the liquid crystal display element has an in-cell touch panel function built into the element. A 3D LCD display element may also be used.

[0148] <<<Circular polarizing plate>>> The circular polarizing plate 60 has the function of suppressing external light reflection, so it can be used as a display element for an OLED element. The circular polarizer 60 is particularly effective when using this method. The circular polarizer 60 is, for example, on the observer's side. To that end, the first phase difference film 61 (hereinafter also referred to simply as "phase difference film 61") There is an adhesive layer 62 and a second phase difference film 63 (hereinafter simply referred to as "phase difference film 63"). It is sometimes referred to as "..." and comprises, in this order, an adhesive layer 64 and a polarizing plate 30.

[0149] In the circular polarizer 60, the second functional layer 13 of the optical film 10 is greater than the first functional layer 12. It is located on the observer's side. By arranging the polarizing plate 30 in this way, the desired pencil hardness can be achieved. This can provide scratch resistance.

[0150] From the viewpoint of achieving a thinner design, the thickness of the circular polarizing plate 60 is preferably 100 μm or less. The lower limit of the thickness of the circular polarizing plate 60 is 20 μm or more, and 30 μm or more, from the viewpoint of processability due to reduced strength. It is preferable that the thickness be 50 μm or more. Also, the upper limit of the thickness of the circular polarizing plate 60. It is more preferable that the thickness is 95 μm or less, 90 μm or less, or 80 μm or less. Circular polarizing plate 6 The thickness of 0 was determined by taking a cross-sectional image of the circular polarizer 60 using a scanning electron microscope (SEM), and In the cross-sectional image, the thickness of the circular polarizer 60 was measured at 10 locations, and the arithmetic average of the thicknesses at those 10 locations was calculated. It can be found by calculating the average value.

[0151] The circular polarizer 60 is manufactured using either a chip-cut method or a roll-to-panel method. It can be incorporated into an image display device. The chip-cut method can be adapted to the size of the image display device. Then, circular polarizing plates of a predetermined size are cut from a roll of circular polarizing plates, and glass is applied via an adhesive layer. This method involves attaching it to a cover material such as a screen. Alternatively, the roll-to-panel method is used in the image display. In the manufacturing line for the display device, a roll-shaped circular polarizing plate is fed out and cut, and then an adhesive layer is applied. This method involves bonding the glass or other cover material to the glass.

[0152] <<First phase difference film>> As the phase difference film 61, a positive C plate or a λ / 4 phase difference film is used. It is possible to be there.

[0153] <Positive C-plate> The positive C-plate is a film that satisfies the relationship nx≒ny < nz, where nx and ny are the refractive indices in the in-plane direction and nz is the refractive index in the thickness direction. By arranging the positive C-plate, the color tone when viewed obliquely with respect to the normal direction of the display screen can be improved. The positive C-plate may be composed of, for example, a vertically aligned liquid crystal layer.

[0154] <λ / 4 retardation film> The λ / 4 retardation film is a film having a characteristic that the in-plane retardation of the film becomes approximately 1 / 4 with respect to a predetermined light wavelength (usually in the visible light region). By arranging the λ / 4 retardation film, linear polarization can be converted into circular polarization or circular polarization can be converted into linear polarization.

[0155] Examples of the λ / 4 retardation film include a λ / 4 retardation film having positive wavelength dispersion and a λ / 4 retardation film having negative wavelength dispersion. The λ / 4 retardation film having positive wavelength dispersion is a film having a property that the retardation becomes smaller as the wavelength becomes longer, and the λ / 4 retardation film having negative wavelength dispersion is a film having a property that the retardation becomes larger as the wavelength becomes longer.

[0156] [[ID=XXX]] The λ / 4 retardation film having positive wavelength dispersion can be obtained by stretching a resin film while adjusting the stretching ratio. Examples of the resin constituting the resin film for obtaining the λ / 4 retardation film include cycloolefin-based resins, cellulose-based resins, etc. The λ / 4 retardation film having negative wavelength dispersion can be obtained by, for example, polycarbonate-based resins or resins having an aromatic structure. [[ID=4XXX]] ​​​​​​​​​​​

[0157] <<adhesive layer>> Adhesive layers 62 and 64 are liquid ionizing radiation-curable adhesives containing polymerizable compounds (e.g., O CR: Optical Clear Resin) cured products and adhesives (e.g., OCA: Optical Clear Adh It can be composed of (esive). The film thickness of the adhesive layers 62 and 64 is 0.5 μm or more. It is preferable that the particle size is 0 μm or less.

[0158] <<Second Phase Difference Film>> If the phase difference film 61 is a positive C plate, then it is phase difference film 63. Therefore, a λ / 4 phase difference film with negative wavelength dispersion (inverse wavelength dispersion) can be used. Furthermore, if the phase difference film 61 is a λ / 4 phase difference film, then the λ / 2 phase difference film Room can be used.

[0159] <λ / 4 phase difference film with negative wavelength dispersion> As a λ / 4 phase difference film having negative wavelength dispersion, the above λ / 4 phase difference film Since it is similar to the λ / 4 phase difference film with negative wavelength dispersion explained in the section, here The explanation will be omitted.

[0160] <λ / 2 phase difference film> A λ / 2 phase difference film is a film that, for a given wavelength of light (usually in the visible light region), This film has the characteristic of having an in-plane phase difference of approximately 1 / 2. By placing a λ / 2 phase difference film, circular polarization can be converted over a wide wavelength range. It is possible.

[0161] λ / 2 phase difference film is produced by stretching a resin film while adjusting the stretching ratio. It can be obtained by the resin that constitutes the resin film for obtaining a λ / 2 phase difference film. Examples include polycarbonate resins and cycloolefin polymer resins. It can be done.

[0162] <<<Touch Sensor>>> A known touch sensor can be used as the touch sensor 70. The 70 types are not particularly limited, but for example, using a capacitive touch sensor The touch sensor 70 is positioned between the circular polarizing plate 60 and the cover member 80. However, it may be placed between the display element 50 and the circular polarizer 60.

[0163] <<<Cover component>>> The surface 80A of the cover member 80 is the surface 40A of the image display device 40. The component 80 may be a cover glass or a cover film made of resin. If the device 40 is flexible, the cover member 80 is made of flexible glass or flexible It is preferable that the resin is made of a resin having flexibility. Examples of flexible resins include Polyimide resins, polyamide-imide resins, polyamide resins, polyester resins (For example, polyethylene terephthalate resin or polyethylene naphthalate resin), or Examples include mixtures obtained by mixing two or more of these resins.

[0164] <<<adhesive layer>>> Adhesive layers 91-93 are liquid ionizing radiation-curable adhesives containing polymerizable compounds (e.g., O CR: Optical Clear Resin) cured products and adhesives (e.g., OCA: Optical Clear Adh It can be composed of (esive).

[0165] OLED elements may degrade due to ambient light, etc. Therefore, currently, OLED elements In image display devices using OLEDs, it is desirable to suppress the degradation of OLED elements. Furthermore, OLED elements emit light called blue light. Blue light is a wave. Light in the wavelength range of 380nm to 500nm has properties similar to ultraviolet light and possesses high energy. Because it has this property, it is not absorbed by the cornea or lens and reaches the retina, causing retinal damage. It is said to cause eye strain and negative effects on sleep. For this reason, blue light is currently It is desirable to shield the light. According to this embodiment, the display element 50 is an OLED element In some cases, the OLED element has a first functional layer 12 containing an ultraviolet absorber on the observer side. Therefore, the first functional layer 12 can absorb ultraviolet light from the ambient light. This can suppress degradation of OLED elements due to ambient light. Furthermore, it can also suppress ultraviolet light emitted from OLED elements. Because it can absorb light, it can block blue light.

[0166] According to this embodiment, when the display element 50 is an OLED element, the view is more visible than with an OLED element. On the side of the observer, there are at least sesamol-type benzotriazole compounds and indole compounds. Since it is equipped with a first functional layer 12 which includes either of the above, the first functional layer 12 filters out the purple light from the ambient light. It can absorb external rays. This suppresses degradation of OLED elements due to ambient light. In addition, it can block the blue light emitted from OLED elements.

[0167] According to this embodiment, the polarizer 31 contains an ultraviolet absorber that absorbs ultraviolet light on the observer side. Since it is equipped with a first functional layer 12, if the display element 50 is an OLED element, This technology can suppress degradation of not only the elements themselves, but also the polarizer due to ambient light.

[0168] Even when the adhesive layer contains the above-mentioned UV absorber, degradation of the OLED element due to ambient light is suppressed. It can do this, and it can also block blue light, but if the adhesive layer contains a UV absorber, Adhesion strength tends to decrease. Therefore, it is difficult to thin the adhesive layer. Also, circularly polarized light Depending on the composition of the board, etc., the type of adhesive layer may be changed, so UV absorption is different for each type of adhesive layer. It is necessary to include an astringent. In contrast, in this embodiment, indentation hardness If the first functional layer 12, which has a pressure of 50 MPa or more and 600 MPa or less, contains an ultraviolet absorber, This makes it possible to thin the first functional layer 12. In addition, by adding an ultraviolet absorber to the first functional layer 12 Since it is included, even if the type of adhesive layer changes depending on the composition of the circular polarizing plate 60, the This can be handled with a single functional layer 12.

[0169] [Second Embodiment] Hereinafter, the optical film and image display device according to the second embodiment of the present invention will be described with reference to the drawings. I will explain this while referring to the figure. Figure 8 is a schematic diagram of the optical film according to this embodiment. Figure 9 is a magnified view of a portion of the optical film in Figure 8, and Figure 10 shows the position for measuring the in-plane phase difference. This is a plan view of the sample for identification. Figures 11 and 12 show the optical system according to this embodiment. This is a schematic diagram illustrating the film manufacturing process.

[0170] <<<<Optical film>>>> The optical film 100 shown in Figure 8 comprises a light-transmitting substrate 101 and a functional layer 102. The functional layer 102 contains an ultraviolet absorber containing nitrogen atoms. The mechanism shown in Figure 8 The functional layer 102 is adjacent to the light-transmitting substrate 101, but the light-transmitting substrate 101 and the functional layer 10 Other functional layers may be provided between layers 2.

[0171] The surface 100A of the optical film 100 shown in Figure 8 is the surface 102A of the functional layer 102. However, if another functional layer is formed on the surface of the functional layer, the optical film The surface of the layer becomes the surface of other functional layers. In this specification, "surface of a functional layer" refers to the functional layer This refers to the side opposite to the side of the light-transmitting substrate.

[0172] The thickness (total thickness), spectral transmittance, yellow index, and total light rays of optical film 100. Physical properties such as transmittance, haze value, pencil hardness, and their measurement methods, flexibility and The evaluation method, as well as the application and size of the optical film 100, are determined by the thickness of the optical film 10. Physical properties such as spectral transmittance, yellow index, total light transmittance, haze value, and pencil hardness. and its measurement method, flexibility and its evaluation method, and the use of the optical film 10 Since the process and size are the same, we will omit the explanation here.

[0173] <<<Light transparent base material>>> The light-transmitting substrate 101 is a substrate that has light-transmitting properties. However, although not particularly limited, from the viewpoint of adhesion between the light-transmitting substrate 101 and the functional layer 102, During the formation of the functional layer 102, the components of the functional layer 102 (e.g., polymerizable compounds) penetrate into the immersion. A permeable substrate may also be used.

[0174] The light-transmitting substrate is not particularly limited in terms of its constituent material, and for example, acetylcellulose resin Fat, cycloolefin polymer resin, (meth)acrylic resin, polyester resin, Polyolefin resins, polyethersulfone resins, polycarbonate resins, poly Polyamide resins, polyimide resins, polyamide-imide resins, polyvinyl chloride resins, poly vinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyaryl Examples include light-transmitting resins such as ion resins and polyphenylene sulfide resins, as well as mixtures thereof. As described in the first embodiment, when the displayed image is observed through polarized sunglasses... Even when combined, the reduction in visibility can be suppressed, making acetylcellulose resin and cyclocellulose resins suitable for this purpose. Refin polymer resins or (meth)acrylic resins are preferred. Also, flexibility From this point of view, polyimide resins and polyamide resins are more preferable. Light-transmitting substrates are used as needed. Furthermore, various additives such as plasticizers, UV absorbers, and lubricants may be added.

[0175] Acetylcellulose resins, cycloolefin polymer resins, (meth)acrylic resins Since fat was described in the first embodiment, its explanation will be omitted here.

[0176] Examples of polyester resins include polyethylene terephthalate (PET) and poly Ethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene Examples include resins containing at least one type of naphthalate (PBN) as a component. When ester-based resins are used, they have the property of being excited and emitting fluorescence when irradiated with ultraviolet light. It is known that such fluorescence can affect the color of the display surface. As mentioned above, the optical film 10 almost completely blocks light with a wavelength of 380 nm or less. Therefore, even if a polyester resin is used for the light-transmitting substrate 11, fluorescence will not occur. This can be effectively prevented.

[0177] Examples of polyolefin resins include polyethylene and polypropylene. Examples of polycarbonate resins include bisphenols (such as bisphenol A). Aromatic polycarbonates based on ) and diethylene glycol bisallyl carbonate Examples include aliphatic polycarbonates such as T.

[0178] Polyimide resins may be aliphatic polyimide resins, but may also contain aromatic rings. Aromatic polyimide resins are preferred. Aromatic polyimide resins are tetracarbon The acidic acid component and the diamine component contain an aromatic ring in at least one of them.

[0179] Polyimide resins may contain a polyamide structure as part of their composition. Examples of polyamide structures include tricarboxylic acid residues such as trimellitic anhydride. Polyamide-imide structures containing such residues, or polyamides containing dicarboxylic acid residues such as terephthalic acid. One example is the polyamide structure. Polyamide resins include not only aliphatic polyamides but also aromatic polyamides. This concept includes mid (aramid).

[0180] Thickness of the light-transmitting substrate 101 (when flexibility is required for the optical film 100) The thickness of the light-transmitting substrate 101 (including the thickness of the substrate) and the method for measuring the thickness, as well as the surface treatment, are light-transmitting The thickness of the substrate 11 and the method for measuring its thickness, as well as the surface treatment, are the same as described here. The explanation will be omitted. Note that if the light-transmitting substrate 101 contains a polyester resin... In cases where flexibility is required for the optical film 100, a light-transmitting substrate is used. The thickness of 101 is similar to the thickness of the light-transmitting substrate 11 containing a cycloolefin polymer resin. That is the case.

[0181] If the light-transmitting substrate 101 contains a polyester resin, the poly within the light-transmitting substrate 101 A uniform distribution of the resin results in superior flexibility. The light-transmitting substrate 101 is made of polyester resin. When it contains fat, stretching is essential to obtain physical strength, so it becomes polymerized. To achieve the most uniformity possible, the material is manufactured by sequential or simultaneous biaxial stretching at approximately the same magnification in both the vertical and horizontal directions. This is desirable. As a result, the in-plane phase difference is smaller than that of conventional light-transmitting substrates containing polyester resins. A light-transmitting substrate containing polyester resin is obtained. In transient substrates, "small in-plane phase difference" refers to light-transmitting substrates containing polyester resins. The thickness is within the range of 10 μm to 90 μm, and the in-plane phase difference is 1500 nm or less. This means that, preferably 1200nm or less, more preferably 1000nm or less, even more preferably The wavelength is 800 nm or less. Note that this refers to a light-transmitting substrate containing biaxially oriented polyester resin. To improve its physical properties, the in-plane phase difference should not be too small, ideally within 200 nm. Furthermore, a wavelength of 400 nm or more is preferable.

[0182] If the light-transmitting substrate 101 contains a polyester resin, the in-plane position of the light-transmitting substrate 101 The phase difference is the refractive index in the slow axis direction, which is the direction in which the refractive index is greatest within the plane of the light-transmitting substrate. nx, refractive index ny in the leading phase axis direction which is perpendicular to the slow phase axis direction in the plane, And, depending on the thickness t (nm) of the light-transmitting substrate, it is expressed by the following formula (4). Yes. According to equation (4) below, a small in-plane phase difference results in a low degree of orientation, thus preventing bending. It can be seen that resistance to erosion can be improved. In-plane phase difference (Re) is, for example, Otsuka Electric Product name "RETS-100" manufactured by our subsidiary, and product name "KOBRA-WR" manufactured by Oji Measuring Instruments Co., Ltd. It can be measured using "PAM-UHR100". In-plane phase difference (Re)=(nx-ny)×t…(4)

[0183] When measuring Re using RETS-100, follow the procedure below. This is possible. First, in order to stabilize the light source of the RETS-100, turn on the light source first. Leave it for 60 minutes or more. Then, select the rotational analyzer method and the θ mode (angular direction position). Select the phase difference measurement mode. By selecting this θ mode, the stage will tilt and rotate. It becomes a stage.

[0184] Next, enter the following measurement conditions into the RETS-100. (Measurement conditions) • Retardation measurement range: Rotational analyzer method • Measurement spot diameter: φ5mm • Inclination angle range: -40° to 40° • Measurement wavelength range: 400nm~800nm • Average refractive index of the sample (polyethylene terephthalate): 1.617 • Thickness: Thickness measured separately using SEM or optical microscope.

[0185] Next, background data is obtained without placing a sample in the device. The device is then closed. This is done in a chain reaction, and this process is performed each time the light source is turned on.

[0186] Next, the sample is placed on the stage inside this device. What is the shape of the sample? The shape may be anything, for example, rectangular. The sample size is 50m The dimensions can be m x 50 mm. If there are multiple samples, they should all be placed in the same orientation. It is necessary to mark all samples in advance so that they are all facing the same direction. It is preferable to leave it attached.

[0187] After setting up the sample, the XY The stage is rotated 360° on a flat surface to measure the leading and lagging phase axes. After the measurement is complete, Select the slow axis. Then, the stage tilts within the set angular range around the slow axis while taking measurements. The process is performed, and data (Re) for the set tilt angle range and set wavelength range is obtained in 10° increments. The in-plane phase difference Re is the value measured with light at an incident angle of 0° and a wavelength of 589 nm. The in-plane phase difference Re is measured at five points at different positions. Specifically, first, as shown in Figure 10... Draw two orthogonal virtual lines IL1 and IL2 passing through the center A1 of sample S2. When these virtual lines IL1 and IL2 are drawn, the sample is divided into four sections. In the drawing, set four points A2 to A4, each equidistant from the center A1, and the center A1 is approximately Measurements are taken at a total of 5 points, A2 to A4. Then, the maximum and minimum values ​​are excluded from the 5 measured values. Let Re be the in-plane phase difference, which is the arithmetic mean of the three points.

[0188] Furthermore, to further improve the physical properties, birefringence in the film thickness direction as well as in the in-plane direction is necessary. The balance of these factors should also be considered. The Nz coefficient is an indicator for this. The Nz coefficient is related to light transmittance. Since this is influenced by the crystallinity and orientation within the substrate, it affects the overall properties of the light-transmitting substrate. The Nz coefficient is generally 2-4, for example, in the case of polyethylene terephthalate. However, in the present invention, 5 or more, more preferably 8 or more, and most preferably 10 or more. The upper limit of the Nz coefficient is approximately 80, preferably 70 or less, and most preferably 50 or less. Below. The Nz coefficient is given by the following formula, where nz is the refractive index in the thickness direction of the light-transmitting substrate. It is expressed by (5). Note that nx and ny in the following formula (5) are This is the same as nx and ny in formula (4) above. Nz coefficient=(nz-nx) / (ny-nx) …(5)

[0189] <<<Functional Layer>>> The functional layer 102 shown in Figure 8 has a single-layer structure, but it can also have a multilayer structure of two or more layers. This is also good. Furthermore, the functional layer 102 is a layer that functions as a hard court layer. However, the function Layer 102 may be a layer having other functions. In this embodiment, the "hard coat layer" "This means that the indentation hardness is greater than the indentation hardness of the light-transmitting substrate." It means a layer.

[0190] The film thickness of the functional layer 102 is between 1 μm and 10 μm. Within this range, it is possible to make the product thinner. The upper limit of this film thickness is 9 μm. The following may be 8 μm or less, or 7 μm or less.

[0191] In this embodiment, "film thickness of the functional layer" refers to the light transmission due to the contrast difference in the microscope image. Since the interface line between the substrate and the functional layer can be recognized, from this interface line to the surface of the functional layer This refers to the distance. The film thickness of the functional layer is measured using a scanning electron microscope (SEM) and a transmission electron microscope ( Using a TEM or scanning transmission electron microscope (STEM), etc., a cross-section of the functional layer is imaged. In the cross-sectional image, the film thickness of the functional layer was measured at 10 locations, and the arithmetic mean of the film thicknesses at those 10 locations was taken. This can be determined by calculating the value. The specific method for taking cross-sectional photographs is described in the first implementation. The method for taking cross-sectional photographs is the same as described in the morphology section, so we will omit the explanation here. ru.

[0192] In functional layer 102, time-of-flight secondary ion mass spectrometry (TOF-SIMS) was performed. When the intensity of secondary ions was measured in the depth direction D1 of the functional layer 102, the surface 1 of the functional layer 102 UV absorber origin in the first region 102C (see Figure 9), which has a thickness of 0.3 μm and includes 02A. The intensity of secondary ions I U1 The functional layer 102 is divided into two equal parts in the depth direction D1 relative to the functional layer 102. In the second region 102D (see Figure 9), which has a thickness of 0.3 μm and includes the bisector IL (see Figure 9), Intensity I of secondary ions derived from UV absorbers U2 The ratio (I U2 / I U1 ) is 1.1 or higher The value becomes 4.0 or less, and the intensity of secondary ions derived from the UV absorber in the second region 102D. I U2 The third region 102E, which includes the back surface 102B of the functional layer 102 and has a thickness of 0.3 μm ( (See Figure 9) Intensity I of secondary ions derived from UV absorbers U3 The ratio (I U3 / I U2 ) The value is between 1.2 and 4.0. U2 / I U1 If it is 1.1 or higher, then the first domain Because 102C does not contain too much UV absorber, the reduction in surface hardness and scratch resistance is less significant. It can suppress the precipitation of UV absorbers and further suppress it. U2 / I U1 4. If the value is 0 or less, there is an extreme concentration of UV absorber between the first region 102C and the second region 102D. Because the difference in intensity is less likely to occur, the second region contains more UV absorbers than the first region 102C. This prevents 102D from becoming too soft, and reduces surface hardness and durability during durability testing. This method can suppress cracks caused by differences in thermal expansion between region 1 (102C) and region 2 (102D). I U3 / I U2 If the value is 1.2 or higher, there is a large amount of UV absorber contained in the second region 102D. Therefore, the precipitation of UV absorbers can be further suppressed. U3 / I U2 If it is 4.0 or less If this occurs, an extreme difference in the concentration of the ultraviolet absorber will be created between the second region 102D and the third region 102E. Because it is difficult to do so, the third region 102E, which contains more UV absorbers than the second region 102D, This prevents excessive softening and reduces surface hardness, as well as the second region 10 during durability testing. This can suppress cracks caused by the difference in thermal shrinkage between 2D and the third region 102E. U2 / I U1 The lower limit is more preferably 1.2 or higher, 1.3 or higher, or 1.4 or higher. The upper limit is 3.5 or less, 3.0 or less, 2.5 or less, 2.0 or less, or 1.6 or less. This is more preferable. Also, I U3 / I U2 The lower limit is 1.3 or higher, 1.4 or higher, 1.6 or lower. It is more preferable to be above or 2.0 or higher, with upper limits being 3.5 or less, 3.2 or less, and 2 It is more preferable that the value is 0.8 or less, 2.6 or less, or 2.5 or less.

[0193] Intensity I of secondary ions derived from UV absorbers in region 102C U1 Third territory against Intensity I of secondary ions derived from UV absorbers in region 102EU3 The ratio (I U3 / I U1 ) It is preferable that the value is between 1.5 and 6.5. U3 / I U1 If it is 1.5 or higher If present, the amount of UV absorber contained in the first region 102C should not be excessive, thus improving surface hardness and abrasion resistance. This further suppresses the reduction in scratch resistance and also further suppresses the precipitation of UV absorbers. U 3 / I U1 If it is 6.5 or less, it can suppress the third region 102E from becoming too soft. This can suppress the decrease in surface hardness. U3 / I U1 The lower limit is 1.8 or higher, 2.0 or higher, It is more preferable that it be 2.2 or higher, and the upper limit is 6.2 or lower, 6.0 or lower, or 5 It is more preferable that it be 0.8 or less.

[0194] In TOF-SIMS, the horizontal axis of the depth profile represents depth, but this depth is related to the functional layer. Since this depth is calculated from the etching rate, the film of the functional layer can be determined from the above cross-sectional photograph. The thickness and the thickness of each region, and the film thickness of the functional layer on the depth profile and each region must always be the same. However, they may not always coincide. The above "bisector that divides the functional layer in the depth direction of the functional layer" is This is an imaginary line that bisects the film thickness of the functional layer in the depth direction of the functional layer, and the above depth profile It is determined based on the thickness of the functional layer required from the above, and the "back surface of the functional layer" is determined from the above The intensity of secondary ions derived from the light-transmitting substrate and the intensity of secondary ions derived from the UV absorber in the pus profile. This is defined as the intersection of the intensities of the second ions. Also, "thickness of the first region", "thickness of the second region", and "third region". The "thickness of the region" shall also be the thickness obtained from the above depth profile. Furthermore, in this specification The "intensity of secondary ions" refers to the difference in depth between regions, unless otherwise specified. The arithmetic mean of the intensity measured at three locations is used for both. Furthermore, the above-mentioned angle bisector IL is in the depth direction. It extends in a direction D2 (see Figure 9) perpendicular to D1, and the second region 102D is the same as the two The equisection line IL is set to be located in the center of the second region 102D.

[0195] The above measurement of secondary ion intensity is performed using a time-of-flight secondary ion mass spectrometer (e.g., ION- This can be done using TOF.SIMS5 from TOF Corporation. Specifically, first, 10 Optical film cut to a size of mm x 10 mm is used in a time-of-flight secondary ion mass spectrometer. The sample chamber is set up so that primary ions are irradiated onto the surface of the functional layer. By irradiating the surface of the functional layer with UV light, the UV absorption in the first, second, and third regions is measured. The intensity of secondary ions derived from the absorbing agent is measured. Note that UV absorbers containing nitrogen atoms contain nitrogen atoms Since it contains CN as a secondary ion derived from the UV absorber - Nitrogen atoms are detected. If the UV absorber containing it is a benzotriazole compound, then the UV absorber is derived from CN as a secondary ion - Ya C6H4N3 - It is detected.

[0196] Using the above TOF.SIMS5, the intensity of secondary ions derived from the UV absorber is measured. When doing so, for example, the following measurement conditions can be used. Ar gas cluster ion beam is used as the etching ion, but By using a gas cluster ion beam, low-damage treatment can be achieved in organic structures. Etching becomes possible. • Secondary ion polarity: Negative ·Mass range (m / z): 0~3000 • Raster size: 200μm□ • Scan rate: 1 scan / cycle • Pixel count (per side): 128 pixels • Measured vacuum level (before sample introduction): 4 × 10 -7 Pa or less • Neutralization of static charge: Yes ·Late acceleration: 10kV • Primary ion: Bi3 ++ • Primary ion acceleration voltage: 30kV Pulse width: 11.3ns • Bunching: Yes (High-mass-resolution measurement) • Etching ions: Ar gas cluster ion beam (Ar-GCIB) • Etching ion acceleration voltage: 20kV • Ar cluster size (median): approximately 1400

[0197] In the functional layer 102, the primary secondary ions derived from the ultraviolet absorber in the first region 102C Small strength I U1(min) However, the second region 102D contains the most secondary ions derived from the UV absorber. Small strength I U2(min) Smaller than, and derived from the UV absorber in the second region 102D. Minimum intensity of secondary ions I U2(min) However, the UV absorber in region 3, 102E, is derived Minimum intensity of secondary ions I U3(min) It is preferable that it be smaller than this. Functional layer 1 In 02, due to this relationship, the surface 102A of the functional layer 102 is connected to the back As the amount of UV absorber gradually increases towards surface 102B, extreme differences in UV absorber concentration occur. This can suppress the occurrence of cracks, and further suppress the occurrence of cracks in the functional layer 102 during durability testing. Cut.

[0198] In the functional layer 102, secondary ions derived from the ultraviolet absorber in the first region 102C maximum strength I U1(max) However, secondary ions derived from UV absorbers in the second region 102D Minimum Intensity I U2(min) Smaller than, and derived from the UV absorber in the second region 102D. Maximum intensity of secondary ions I U2(max) However, the UV absorber originates in region 3, 102E. Minimum intensity I of secondary ions U3(min) It is preferable that it be smaller than the functional layer. In 102, due to this relationship, from the surface 102A of the functional layer 102 The amount of UV absorber gradually increases towards the reverse side 102B, resulting in extreme differences in UV absorber concentration. This can suppress the occurrence of cracks, and further suppress the occurrence of cracks in the functional layer 102 during durability testing. can.

[0199] In the functional layer 102, secondary ions derived from the ultraviolet absorber in the first region 102C Minimum Intensity I U1(min) However, the light-transmitting substrate 11 of the first region 102C in the functional layer 102 UV absorber origin in the fourth region 102F from the side boundary 102C1 to the back surface 102B Minimum intensity I of secondary ions U4(min) It is preferable that it be smaller than the functional layer 102. Therefore, due to this relationship, in the functional layer 102, the first region 102C Because it contains the least amount of UV absorber, it is less prone to UV absorber precipitation, reduced surface hardness, and abrasion resistance. This can further suppress the deterioration of wounds.

[0200] Functional layer 102 may contain a fluorine atom-containing compound as described later, but functional layer 1 If 02 contains a fluorine atom-containing compound, the first region 1 measured by TOF-SIMS The intensity I of secondary ions derived from the fluorine atom-containing compound in 02C F1 is greater than that in the second region 102 D and the respective intensities of secondary ions derived from the fluorine atom-containing compound in the third region 102E intensity I F2 , I F3 is preferably larger. That is, the fluorine atom-containing compound is unevenly distributed on the surface 102A side (first region 102C) of the functional layer 102. Due to the above intensity I F1 being larger than the above intensity I F2 , I F3 being larger, there is more fluorine atom-containing compound in the first region 102C of the functional layer 102, so the precipitation of the ultraviolet absorber on the surface 102A can be suppressed.

[0201] The ratio (I of the intensity I of secondary ions derived from the fluorine atom-containing compound in the second region 102D and the third region 102E F2 , I F3 to the intensity I of secondary ions derived from the fluorine atom-containing compound in the first region 102C of the fluorine atom-containing compound (I F1 [[ID=……]]is more preferably.

[0202] ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Functional layer 102 may contain a silicon atom-containing compound as described later, but functional layer 1 If 02 contains a silicon atom-containing compound, the first region 1 measured by TOF-SIMS Intensity I of secondary ions derived from silicon atom-containing compounds at 02C S1 However, in the second area 102 The respective secondary ions derived from silicon atom-containing compounds in regions D and 3, region 102E Strength I S2 , I S3 It is preferable that it is larger than that. That is, silicon atom content The compound is unevenly distributed on the surface 102A side (first region 102C) of the functional layer 102. Degree I S1 However, the above strength I S2 , I S3 Because it is larger than, the silicon atom content Since the compound is abundant in the first region 102C of the functional layer 102, the UV absorber is on the surface 102A. This can suppress precipitation.

[0203] Secondary aions derived from silicon atom-containing compounds in the second region 102D and the third region 102E ON intensity I S2 , I S3 Derived from silicon atom-containing compounds in the first region 102C. The intensity of secondary ions I S1 The ratio (I S1 / I S2 , I S1 / I S3 ) each of 3 or more It is preferable that it be so. S1 / I S2 and I S1 / I S3 If each of them is 3 or more This further suppresses the deposition of UV absorbers on surface 102A. S1 / I S2 and I S1 / I S3The lower limits are preferably 5 or higher, 10 or higher, or 15 or higher, respectively. It seems so.

[0204] Intensity of secondary ions and silicon atoms derived from fluorine-containing compounds by TOF-SIMS The intensity of secondary ions derived from the ion-containing compound is the same as the intensity of secondary ions derived from the UV absorber mentioned above. It can be measured by various methods. Note that fluorine atom-containing compounds contain fluorine atoms, so As a secondary ion derived from a compound containing an oxypodium atom, F - It is detected. Also, silicon atom-containing Since the compound contains silicon atoms, SiO2 is derived from the silicon atom-containing compound as a secondary ion. - It is detected.

[0205] The indentation hardness of functional layer 102 is between 75 MPa and 1000 MPa. Preferably, if the indentation hardness of the functional layer 102 is 75 MPa or higher, It can achieve the desired pencil hardness, and if the pressure is below 1000 MPa, it can suppress crack formation. It can be controlled. The lower limit of the indentation hardness of functional layer 102 is 100 MPa or higher, and 150 MPa. It is preferable that the pressure be MPa or higher, or more preferably 200 MPa or higher. Also, the functional layer 102 The upper limit for indentation hardness is 900 MPa or less, 750 MPa or less, or 600 MPa. It is more preferable that it be less than MPa. The indentation hardness of the functional layer 102 is first Measurement shall be performed by the method described in the embodiment.

[0206] Functional layer 102 contains a resin and an ultraviolet absorber containing nitrogen atoms. Functional layer 102 In addition to resins and UV absorbers, it also contains fluorine atom-containing compounds, silicon atom-containing compounds, and heavy It may contain a combination initiator.

[0207] <Resin> The resin included in the functional layer 102 includes polymers (cured products) of polymerizable compounds. Yes, resins include polymers of polymerizable compounds, as well as solvent-drying resins and thermosetting compounds. This is also acceptable. The polymerizable compound is the same as the polymerizable compound described in the section for the second functional layer 13. Therefore, we will omit the explanation here. Solvent-drying resins and thermosetting compounds are first function Since it is similar to the solvent-drying resins and thermosetting compounds described in section 12, it will not be explained here. This part shall be omitted.

[0208] <UV absorber> The ultraviolet absorber is the same as the ultraviolet absorber described in the first embodiment, so it will not be explained here. The term "Akira" will be omitted.

[0209] <Fluorine atom-containing compounds> Fluorine atom-containing compounds are not particularly limited as long as they contain fluorine atoms. Examples of fluorine atom-containing compounds include fluorine-based leveling agents. By using a leveling agent, high leveling properties are achieved, resulting in smoothness and recoatability. It can be provided. Examples of commercially available fluorine-based leveling agents include F-555 (DIC Corporation). (Manufactured by [Company Name]), F-568 (Manufactured by DIC Corporation), F-568 (Registered Trademark) 683 (Company Name) (Manufactured by Neos Co., Ltd.) is one example.

[0210] <Silicon atom-containing compounds> The silicon atom-containing compound is not particularly limited as long as it contains silicon atoms. Examples of silicon atom-containing compounds include silica particles and silicon-based leveling agents. When silica particles are used, the functional layer 102 can be given slipperiness.

[0211] The average particle size of the silica particles is preferably between 1 nm and 1000 nm. If the average particle size is 1 nm or larger, silica particles can be easily manufactured, and 1 Below 000nm, slipperiness can be imparted while maintaining high transparency. The average particle size of the cubic From images of the cross-section of silica particles taken at magnifications of 40,000x to 200,000x using M), 20 silica The particle size of the silica particles is measured and the arithmetic mean of the particle sizes of 20 silica particles is taken.

[0212] The functional layer 102 may be formed using one type of composition, or it may be formed using two or more types of compositions. It is possible to form it using two or more compositions. For example, a first set of functional layers containing a polymerizable compound and an ultraviolet absorber containing nitrogen atoms. The functional layer may be formed using a second composition for the functional layer containing the product and polymerizable compounds.

[0213] <First composition for functional layer> The first composition for the functional layer contains the above polymerizable compound and an ultraviolet absorber, but also contains other necessary components. Depending on the requirements, it may also contain polymerization initiators, solvents, leveling agents, etc. Polymerization initiators, solvents, The leveling agent is the same as the polymerization initiator, solvent, and leveling agent described in the first embodiment. Therefore, we will omit the explanation here.

[0214] <Second composition for functional layer> The second composition for the functional layer contains the above polymerizable compound, etc., but also contains the above fluorine atom-containing Compound, the silicon atom-containing compound, the solvent-drying resin, the thermosetting compound, polymerization initiation It may contain agents, solvents, etc. Furthermore, the second composition for the functional layer may, if necessary, contain the present invention. The following additives may be included, to the extent that they do not impair the effect. For example, antistatic agents, adhesion improvers, thixotropic agents, coupling agents, plasticizers, Examples include defoaming agents, fillers, and colorants.

[0215] The polymerization initiator in the second functional layer composition is the same as the polymerization initiator in the first functional layer composition. It may be, but it is preferable that it be different. Polymerization initiation in the second composition for the functional layer By using a different agent than the polymerization initiator in the first composition for the functional layer, the first set for the functional layer For the finished product, a polymerization initiator that is easy to partially cure was selected, and for the second composition for the functional layer, the table A polymerization initiator with good surface hardening properties can be selected.

[0216] <<Manufacturing method for optical film>> The optical film 100 can be manufactured, for example, as follows. First, Figure 1 As shown in 1(A), a functional layer is applied to one surface 101A of the light-transmitting substrate 101. 1. Apply the composition and allow it to dry to form the first coating film 111. Next, as shown in Figure 11(B) As shown, the first coating film 111 is irradiated with ionizing radiation such as ultraviolet light to polymerize the polymerizable compound. The first coating film 111 is partially cured by cross-linking.

[0217] After the first coating 111 has partially cured, the second functional layer composition is applied to the surface of the first coating 111. And when dried, as shown in Figure 12(A), in addition to the second coating 112, the first coating 1 A mixed coating containing the components of the first coating 111 and the components of the second coating 112 is applied between 11 and the second coating 112. A film 113 is formed. The mixed coating film 113 is, for reasons that are not clear, a second composition for the functional layer. As the solvent penetrates the semi-cured first coating film 111, the polymerizable compound components also become semi-cured. It is thought that the material is drawn into the first coating film 111 in a molten state and formed there.

[0218] Next, as shown in Figure 12(B), the first coating 111, the second coating 112 and the mixture The coating film 113 is irradiated with ionizing radiation such as ultraviolet light to polymerize (crosslink) polymerizable compounds. This causes the first coating film 111, the second coating film 112, and the mixed coating film 113 to harden (for example, fully hardened). ) to be cured. Here, the first coating film 111, the second coating film 112, and the mixed coating film 113 are cured. Then, each interface disappears, and a single functional layer 102 is formed.

[0219] According to this embodiment, the film thickness of the functional layer 102 is 1 μm or more and 10 μm or less, and the function In an optical film 100 in which layer 102 contains an ultraviolet absorber containing nitrogen atoms, the first region 1 Intensity I of secondary ions derived from UV absorbers at 02C U1 In the second region 102D for Intensity I of secondary ions derived from UV absorbers U2 The ratio (I U2 / I U1 ) is 1.1 or higher Since it is 4.0 or less, there is less UV absorber near the surface 102A of the functional layer 102. It is as follows. Also, the intensity I of secondary ions derived from the UV absorber in the second region 102D U Intensity I of secondary ions derived from UV absorbers in the third region 102E relative to 2 U3 ratio ( I U3 / I U2 Since ) is between 1.2 and 4.0, the first domain 1 of functional layer 102 This can suppress the occurrence of extreme concentration differences in UV absorbers in the 02C to 3rd region 102E. This suppresses the occurrence of cracks in the functional layer 102 during durability testing. This allows for a thinner design. An optical film that achieves good surface hardness, good scratch resistance, and good durability. A value of 100 can be obtained. Note that "good surface hardness" in this specification means at least This also means a surface hardness such that the optical film 100 will not be scratched during processing, and also "good durability "Abrasion resistance" means that the optical film 100 is at least not scratched during processing. It means scratch resistance.

[0220] <<<Polarizing plates and image display devices>>> The optical film 100, like the optical film 10, can be incorporated into polarizing plates and image display devices. It can be used. Figure 13 is a schematic diagram of the polarizing plate according to this embodiment. Figure 14 is a schematic diagram of the image display device according to this embodiment. Polarizing plate 1 shown in Figure 13 The image display device 130 shown in Figure 20 and Figure 14 includes an optical film 100. In Figures 13 and 14, the components that have the same reference numerals as those in Figures 6 and 7 are, in Figure 6 Since it is the same as the component shown in Figure 7, its explanation will be omitted. [Examples]

[0221] To explain the present invention in detail, examples will be given below, but the present invention is these This is not limited to what is written. Furthermore, unless otherwise specified, "part" or "%" in the text refers to... It will be based on mass.

[0222] <<Example A and Comparative Example A>> <Example A1> (Preparation of underlayer composition 1) A 200 mL four-necked flask is fitted with a ball-type condenser, a mercury thermometer, and a stirring device. , 6-[5-(2-hydroxyethyl)-2H-benzotriazol-2-yl]benzo [1,3] Dioxol-5-ol 4.0g (0.013 mol), Toluene 40mL, 1.8g (0.021 mol) of methacrylic acid, 0.4g (0.004 mol) of methanesulfonic acid Add ) and reflux dehydration at 110-115°C for 4 hours. Then add 30 mL of water and sodium carbonate. Add 0.6g (0.006 mol) of um, let it stand, separate and remove the aqueous layer at the bottom, and activate 0.2g of charcoal was added and the mixture was stirred under reflux to decolorize it. After filtration, toluene was extracted from the filtrate. 40 mL was recovered by reducing the pressure, and 100 mL of isopropyl alcohol was added and precipitated. The extracted crystals were filtered and washed with 40 mL of isopropyl alcohol. Then, under reduced pressure for 40°C. The mixture was dried at °C to obtain 4.2 g of yellow crystals. These 4.2 g of yellow crystals were mixed with isopropyl alcohol. It was then repulped and washed, and dried under reduced pressure at 40°C. This resulted in sesamol-type benzotrione. As a zole compound, 3.4 g of 2-[2-(6-hydroxybenzo[1,3]dioxy [Sol-5-yl)-2H-benzotriazole-5-yl]ethyl methacrylate is obtained. Ta.

[0223] Next, a four-necked flask is fitted with a Liebig condenser, a mercury thermometer, a nitrogen gas inlet tube, and a stirring device. The apparatus was attached and the synthesized 2-[2-(6-hydroxybenzo[1,3]dioxole- 16 parts by mass of 5-yl)-2H-benzotriazole-5-yl]ethyl methacrylate, 24 parts by mass of methyl methacrylate (MMA) as another monomer, and toluene as a solvent. 20 parts by mass, 20 parts by mass of methyl ethyl ketone, and 1,1'-A as a polymerization initiator. Add 0.6 parts by mass of Zobis(cyclohexane-1-carbonitride) and stir while nitrating. After purging the flask with nitrogen at a gas flow rate of 10 mL / min for 1 hour, the reaction mixture temperature was 90-96°C. The polymerization reaction was carried out under reflux at °C for 10 hours.

[0224] After the polymerization reaction is complete, add 10 parts by mass of toluene and 10 parts by mass of methyl ethyl ketone (MEK). In addition, acrylic polymers in which sesamol-type benzotriazole compounds react and bond to MMA 100.6 parts by mass of a solution containing M1 (ultraviolet absorber 1) was obtained.

[0225] The above acrylic polymer 1 is tricyclodecane dimethanol diacrylate (product name "A -DCP (manufactured by Shin Nakamura Chemical Industry Co., Ltd.) is mixed with a solid content mass ratio of 60:40, and then added Initiator (Omnirad184 and BASF resin from IGM Resins BV) IRGACURE(registered trademark) OXE01 manufactured by Japan Co., Ltd. (mass ratio 50:50) 4 parts by mass and Add 0.2 parts by mass of a leveling agent (product name "F-568", manufactured by DIC Corporation). The mixture was thoroughly stirred to prepare base layer composition 1.

[0226] (Preparation of composition 1 for hard coat layer) The above acrylic polymer 1 is mixed with dipentaerythritol hexaacrylate and dipentaerythritol. A mixture of thritol pentaacrylate (product name "KAYARAD DPHA", manufactured in Japan) Mix with (manufactured by Yakuhin Co., Ltd.) in a solid content mass ratio of 45:55, and then add polymerization initiator (IGM Res Omnirad184 manufactured by ins BV and ESACU manufactured by DKSH Japan. RE ONE (mass ratio 50:50) 4 parts by mass, and leveling agent (product name "F-568") Add 0.2 parts by mass of (manufactured by DIC Corporation) and stir well to form Hard Coat Layer Composition 1 We prepared it.

[0227] (Production of optical films) The obtained base layer composition 1 was prepared in Miyabar with a size of 210mm x 297mm (A4 size). (Is) and a cycloolefin polymer substrate with a thickness of 50 μm (product name "Zeonoafy") Apply to the surface of "Lum (registered trademark) ZF14-050" (manufactured by Nippon Zeon Co., Ltd.) and the first A coating film was formed. Next, the formed first coating film was subjected to drying at 50°C at a flow rate of 0.5 m / s. By circulating dry air for 30 seconds, the solvent in the first coating film is evaporated, and the ultraviolet light is used to calculate the total amount of light. 120 mJ / cm 2 The first coating was partially cured by irradiating it in such a manner.

[0228] After forming the semi-cured first coating film, a hard coat layer is applied to the surface of the first coating film using Miyaba. Composition 1 was applied to form a second coating film. Then, 0.5 By circulating 70°C dry air at a flow rate of m / s for 30 seconds, the solvent in the second coating film is vaporized. By emitting ultraviolet light and accumulating it in a nitrogen atmosphere (oxygen concentration of 200 ppm or less), the total light intensity reaches 200 mJ / cm 2 By irradiating the first and second coating films in such a way that they harden, the first function is achieved. The base layer has a thickness of 1 μm, the mixed layer has a thickness of 0.4 μm, and the second functional layer has a thickness of [number missing]. This formed a 3 μm hard coat layer on the cycloolefin polymer substrate. An optical film was obtained having a base layer, a mixed layer, and a hard coat layer in this order.

[0229] The thickness of the underlying layer was determined by taking a cross-sectional image of the underlying layer using a scanning transmission electron microscope (STEM). The thickness of the underlying layer was measured at 10 locations in the cross-sectional image, and the arithmetic average of the thicknesses at those 10 locations was calculated. An average value was used. The specific method for taking cross-sectional photographs was as follows: First, 1mm x 10mm A block is prepared by embedding an optical film cut out with embedding resin, and this block From there, using a general sectioning method, a uniform section free of holes, etc., with a thickness of approximately 70nm to 300nm is prepared. Sections were cut out. The sections were prepared using the "Ultramicrotome EM UC7" (Leica). Microsystems Co., Ltd., etc. were used. Then, a uniform section without holes, etc., was measured. It was simplified. Afterwards, a scanning transmission electron microscope (STEM) (product name "S-4800") Cross-sectional images of the measurement sample were taken using a device manufactured by Hitachi High-Technologies Corporation. When taking cross-sectional images using the S-4800, set the detector to "TE" and the acceleration voltage to "3 Cross-sectional observation was performed with a voltage of 0kV and an emission current of 10μA. Regarding magnification, Adjust the focus and observe whether each layer can be distinguished by contrast and brightness while applying the base coat. The magnification was adjusted appropriately within a range of 10,000 to 100,000 times depending on the thickness of the layer. Furthermore, the condenser lens The value was set to "5.0", and the WD was set to "8.9mm". Also, the mixed layer and hard coat The thickness of the undercoat layer was measured using the same method as the thickness of the undercoat layer. (Note: Examples A2-A1) In Example 6 and Comparative Examples A1-A6, the base layer and mixed layer were prepared using the same method as in Example A1. The thickness of the hard coat layer was measured.

[0230] <Example A2> In Example A2, the cumulative light intensity was 20 in a nitrogen atmosphere (oxygen concentration of 200 ppm or less). 0 mJ / cm 2 By irradiating the first coating with ultraviolet light, the first coating is partially cured, and the film thickness is reduced. The optical film was prepared in the same manner as in Example A1, except that a 0.04 μm mixed layer was formed. I got it.

[0231] <Example A3> In Example A3, the integrated light intensity was 200 mJ / cm². 2 The first coating is exposed to ultraviolet light in such a way. Aside from irradiating the first coating film to partially cure it and forming a mixed layer with a thickness of 0.2 μm, An optical film was obtained in the same manner as in Example A1.

[0232] <Example A4> In Example A4, the thickness of the underlayer was set to 1.2 μm, and the integrated light intensity was 70 mJ / cm 2 By irradiating the first coating with ultraviolet light, the first coating is partially cured, and the thickness of the mixed layer is determined. Aside from setting the thickness to 1 μm and the hard coat layer thickness to 3.1 μm, the process was carried out. An optical film was obtained in the same manner as in Example A1.

[0233] <Example A5> In Example A5, the integrated amount of ultraviolet light was 100 mJ / cm². 2 First coating The first coating film was partially cured by irradiation, and the thickness of the mixed layer was set to 0.5 μm, and An optical film was obtained in the same manner as in Example A1, except that the thickness of the docoat layer was set to 8 μm. Ta.

[0234] <Example A6> In Example A6, the integrated ultraviolet light intensity was 70 mJ / cm². 2 To achieve this, the first coating The first coating was partially cured by irradiation, and the thickness of the mixed layer was set to 1 μm, and the hard coat An optical film was obtained in the same manner as in Example A1, except that the thickness of the t-layer was set to 0.5 μm. .

[0235] <Example A7> In Example A7, underlayer composition 2 was used instead of underlayer composition 1, and Except for using hard coat layer composition 2 instead of hard coat layer composition 1, An optical film was obtained in the same manner as in Example A1. Composition 2 for the undercoat and for the hard coat layer. Composition 2 was prepared as follows: (Preparation of underlayer composition 2) The above acrylic polymer 1 is converted to dicyclopentenyl acrylate (product name "FA-511A Mix "S" (manufactured by Hitachi Chemical Co., Ltd.) with solids at a mass ratio of 60:40, and then add polymerization initiator (I Omnirad184 and Omnirad819 manufactured by GM Resins BV (Mass ratio 50:50) 4 parts by mass and leveling agent (product name "F-568", DIC Corporation) 0.2 parts by mass of (manufactured) was added and thoroughly stirred to prepare base layer composition 2.

[0236] (Preparation of composition 2 for hard coat layer) The above acrylic polymer 1 is urethane acrylate (product name "Beamset 577", rough Mix with (manufactured by Kawakagaku Kogyo Co., Ltd.) in a solid content mass ratio of 45:55, and then add a polymerization initiator (IGM) to this mixture. Mass of Omnirad184 and Omnirad819 manufactured by Resins BV (Ratio 50:50) 4 parts by mass and leveling agent (product name "F-568", manufactured by DIC Corporation) 0.2 parts by mass were added and the mixture was thoroughly stirred to prepare hard coat layer composition 2.

[0237] <Example A8> In Example A8, underlayer composition 2 was used instead of underlayer composition 1, and By using hard coat layer composition 2 instead of hard coat layer composition 1, the film thickness is 0. An optical film was obtained in the same manner as in Example A2, except that a 0.4 μm mixed layer was formed.

[0238] <Example A9> In Example A9, underlayer composition 2 was used instead of underlayer composition 1, and By using hard coat layer composition 2 instead of hard coat layer composition 1, the film thickness is 0. An optical film was obtained in the same manner as in Example A3, except that a 2 μm mixed layer was formed.

[0239] <Example A10> In Example A10, underlayer composition 3 was used instead of underlayer composition 1. Except for the above, an optical film was obtained in the same manner as in Example A1. The underlayer composition 3 is as follows: It was prepared in this way. (Preparation of underlayer composition 3) Indole compound (product name "BONASORB UA-3912", Orient Chemical Co., Ltd.) (Manufactured by Kogyo Co., Ltd.) (UV absorber 2) dicyclopentenyl acrylate (product name "FA Mix "-511AS" (manufactured by Hitachi Chemical Co., Ltd.) with a solid content mass ratio of 10:90, and polymerize it. Initiators (Omnirad184 and Omnirad manufactured by IGM Resins BV) 4 parts by mass of d819 (mass ratio 50:50) and leveling agent (product name "F-568", DI 0.2 parts by mass of (manufactured by C Corporation) was added and thoroughly stirred to prepare base layer composition 3.

[0240] <Example A11> In Example A11, underlayer composition 4 was used instead of underlayer composition 1. Except for the above, an optical film was obtained in the same manner as in Example A1. The underlayer composition 4 is as follows: It was prepared in this way. (Preparation of underlayer composition 4) Hydroxyphenyltriazine-based UV absorber (product name "Tinuvin479", B ASF Corporation (UV absorber 3) dicyclopentenyl acrylate (product name "FA-5 Mix "11AS" (manufactured by Hitachi Chemical Co., Ltd.) with a solid content mass ratio of 30:70, and begin polymerization. Agents (Omnirad184 and Omnirad8 manufactured by IGM Resins BV) 19 (mass ratio 50:50) 4 parts by mass and leveling agent (product name "F-568", DIC strain 0.2 parts by mass of (manufactured by Co., Ltd.) was added and thoroughly stirred to prepare underlayer composition 4.

[0241] <Example A12> In Example A12, a cycloolefin polymer substrate with a thickness of 50 μm (product name " Instead of "Zeonor Film (registered trademark) ZF14-050" (manufactured by Zeon Corporation of Japan) , a cycloolefin polymer substrate with a thickness of 50 μm (product name "Zeonor Film" (registered trademark) (Standard) ZF14-050 (manufactured by Zeon Corporation) to achieve an in-plane phase difference of 100 nm A cycloolefin polymer system with a thickness of 25 μm, produced by stretching at 150°C. An optical film was obtained in the same manner as in Example A1, except that a substrate was used.

[0242] <Example A13> In Example A13, instead of a cycloolefin polymer substrate, a 60 μm thick substrate was used. Triacetylcellulose base material (product name "Fujitac TD60UL", Fujifilm Corporation) An optical film was obtained in the same manner as in Example A1, except that a company-made product was used.

[0243] <Example A14> In Example A14, instead of a cycloolefin polymer substrate, a 25 μm thick substrate was used. Triacetylcellulose base material (product name "Fujitac TJ25UL", Fujifilm Corporation) An optical film was obtained in the same manner as in Example A1, except that a company-made product was used.

[0244] <Example A15> In Example A15, instead of a cycloolefin polymer substrate, a 40 μm thick substrate was used. Acrylic resin substrate (product name "OXIS(registered trademark)-ZU (40μm)", Okura Industries Co., Ltd.) An optical film was obtained in the same manner as in Example A1, except that (manufactured by Co., Ltd.) was used.

[0245] <Example A16> In Example A16, instead of a cycloolefin polymer substrate, a 30 μm thick Acrylic resin substrate (product name "OXIS(registered trademark)-ZU (30μm)", Okura Industries Co., Ltd.) An optical film was obtained in the same manner as in Example A1, except that (manufactured by Co., Ltd.) was used.

[0246] <Comparative Example A1> Substrate composition 1 is prepared at Miyabar in a size of 210mm x 297mm (A4 size). A cycloolefin polymer substrate with a thickness of 50 μm (product name "Zeonor Film (Registered) Apply to the surface of (registered trademark) ZF14-050 (manufactured by Nippon Zeon Co., Ltd.) to form a coating film. Next, dry air at 50°C was blown onto the formed coating film at a flow rate of 0.5 m / s for 30 seconds. By circulating the solution, the solvent in the first coating film is evaporated, and ultraviolet light is applied to a nitrogen atmosphere (oxygen concentration 20%). (0 ppm or less) Integrated light intensity of 400 mJ / cm 2 Irradiate in such a way that the first coating is completely This was done to create a base layer with a thickness of 1 μm.

[0247] After forming the fully cured first coating film, a hard coat layer is applied to the surface of the first coating film using Miyaba. Composition 1 was applied to form a second coating film. Then, 0.5 m was applied to the formed coating film. By circulating 70°C dry air at a flow rate of / s for 30 seconds, the solvent in the coating film is evaporated. Ultraviolet light was applied in a nitrogen atmosphere (oxygen concentration 200 ppm or less) with an accumulated light intensity of 200 mJ / cm². 2 By irradiating the coating to harden it, a hard coat layer with a thickness of 3 μm is formed. This was accomplished. As a result, a base layer and a hard coat layer are formed on the cycloolefin polymer substrate. An optical film was obtained that had the following in this order. In the optical film according to Comparative Example A1 No mixed layer was formed.

[0248] <Comparative example A2> In Comparative Example A2, the thickness of the underlayer was set to 1.2 μm, and ultraviolet light was applied in a nitrogen atmosphere. (Oxygen concentration 200 ppm or less) with an integrated light intensity of 300 mJ / cm 2 To achieve this, the first coating Except for irradiating the first coating to partially cure it and setting the thickness of the mixed layer to 0.01 μm, the procedure was carried out. An optical film was obtained in the same manner as in Example A1.

[0249] <Comparative example A3> In Comparative Example A3, the thickness of the underlayer was set to 1.2 μm, and ultraviolet light was applied in a nitrogen atmosphere. (Oxygen concentration 200 ppm or less) Integrated light intensity 200 mJ / cm 2 To achieve this, the first coating The first coating was partially cured by irradiation, and the thickness of the mixed layer was set to 0.05 μm, and An optical film was obtained in the same manner as in Example A1, except that the thickness of the docoat layer was set to 8 μm. Ta.

[0250] <Comparative example A4> In Comparative Example A4, the integrated ultraviolet light intensity was 50 mJ / cm². 2 To achieve this, the first coating The first coating was partially cured by irradiation, and the thickness of the mixed layer was set to 2.0 μm, and hard An optical film was prepared in the same manner as in Example A1, except that the thickness of the coating layer was set to 1.0 μm. I got it.

[0251] <Comparative Example A5> In Comparative Example A5, underlayer composition 2 was used instead of underlayer composition 1, and Except for using hard coat layer composition 2 instead of hard coat layer composition 1, An optical film was obtained in the same manner as in Comparative Example A1.

[0252] <Comparative example A6> In Comparative Example A6, instead of a cycloolefin polymer substrate, a 50 μm thick substrate was used. Polyethylene terephthalate substrate (product name "Cosmoshine (registered trademark) A4100") An optical film was obtained in the same manner as in Example A1, except that a product manufactured by Toyobo Co., Ltd. was used.

[0253] <Maximum absorption wavelength and absorbance at wavelengths of 380nm to 500nm> Maximum absorption wavelength λ of UV absorber 1 (acrylic polymer 1) max and wavelength 380nm Absorbance at ~500nm was measured using a spectrophotometer (product name "UV-2450", Shimadzu Corporation). Measurements were taken using a tungsten lamp and a deuterium lamp (manufactured by the manufacturer). UV absorber 1 Maximum absorption wavelength λ max And the absorbance measurement was performed by reducing the solution containing the obtained UV absorber 1. The procedure was performed after desolvent removal by pressure drying, using a 40 ppm chloroform solution. The measurement of the maximum absorption wavelength λmax and absorbance of the ultraviolet absorbers 2 and 3 was performed using ultraviolet absorbers 2 and 3. The test was conducted using a 40 ppm chloroform solution. The results were as follows: [Table 1]

[0254] <Adhesion> In the optical films of Examples A1 to A16 and Comparative Examples A1 to A6, durability tests were performed. The test was conducted, and the adhesion before and after the durability test was evaluated. Specifically, the size was 100mm x 100mm. The cut optical film is then subjected to a durability testing device (product name "Constant Temperature and Humidity Chamber PL-1KP", S Placed inside (manufactured by PEC Corporation) and kept under conditions of 85 degrees Celsius and 85% relative humidity for 240 hours. A durability test was conducted by leaving the product unattended for an extended period. The optical film was free of defects (inclusion of foreign matter) and showed no cracks. It must be free of wrinkles and stains, and in a flat, curl-free state, as tested for durability. It was placed inside.

[0255] Then, the adhesion before and after the durability test was evaluated under conditions of 23°C and 50% relative humidity. Specifically, first, the optical films relating to Examples A1 to A16 and Comparative Examples A1 to A5. Using a utility knife, draw a 10x10 grid at 1mm intervals in mutually orthogonal directions. Cuts were made in a grid pattern. The cuts penetrated the hard coat layer and the undercoat layer. It was poured deep enough to reach the cycloolefin polymer substrate. A grid formed and cured. Apply adhesive tape (model number "No. Attach "405" (manufactured by Nichiban Co., Ltd., 24mm wide) and one end of the attached adhesive tape. Grasp it, hold it almost perpendicular to the surface of the hard coat layer, and instantly peel it off to remove adhesion. The following was evaluated. The evaluation criteria were as follows. Note that the number of remaining items was 100. If there was no detachment due to peeling, it is indicated as 100 / 100, and if all detached, it is indicated as 0 / It was written as 100. A: 100 / 100 B: 99 / 100~50 / 100 C:0 / 100~49 / 100

[0256] <Pencil hardness> Surface (hard coat layer) of optical films in Examples A1-A16 and Comparative Examples A-A6 The pencil hardness on the surface was measured for each. Note that when measuring pencil hardness, optical A sample cut from the film to a size of 50mm x 100mm is placed on a glass plate and folded. With the pencil hard, secured with cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. to prevent wrinkles, Hardness tester (product name: "Pencil scratch coating hardness tester (electric type)", Toyo Seiki Seisakusho Co., Ltd.) Using (manufactured by) in an environment with a temperature of 23°C and relative humidity of 50% or less, pencils (product name "Uni") A 300g load is applied to a pencil (manufactured by Mitsubishi Pencil Co., Ltd.) while it is moved at a speed of 3mm / second. Pencil hardness is the hardest hardness that does not cause any scratches on the surface of the sample during the pencil hardness test. The degree is set to 1 degree. Note that when measuring pencil hardness, multiple pencils with different hardness levels are used, but lead Each pencil was subjected to a pencil hardness test five times, and the surface of the sample was examined under fluorescent light at least four of those five times. If no scratches are visible on the surface of the sample during transmission observation, then use a pencil of this hardness. Therefore, we can conclude that the surface of the sample was not damaged.

[0257] <Visibility Evaluation> Visibility evaluation was performed using the optical films of Examples A1 to A16 and Comparative Examples A1 to A6. This was done. Specifically, OLED display devices (product name "Galaxy SII", Sams An optical film cut to a size of 50mm x 50mm is placed on top of (made by ung company), With the lights turned on, in both dark and bright conditions (illuminance around the OLED display device: 400 lux), the polarity was observed. The displayed images were observed through the light-reflecting sunglasses, and the presence or absence of rainbow irregularities was evaluated according to the following criteria. It was worthwhile. The observation was conducted by 10 people, and the evaluation with the highest number of votes was used as the observation result. A: No rainbow distortion was observed through polarized sunglasses, indicating good visibility. B: Some rainbow-like unevenness was observed through polarized sunglasses, but visibility was good. C: Strong rainbow patterns were observed through polarized sunglasses, resulting in poor visibility.

[0258] <Spectral transmittance> In the optical films according to Examples A1 to A11, A13, and A15, the temperature was 23°C and Under a relative humidity of 50%, wavelengths of 380nm, 400nm, 410nm, and 440nm The spectral transmittance at m was measured. Specifically, it was cut to a size of 50 mm x 50 mm. A spectrophotometer (product name "UV-") capable of measuring the transmittance of an optical film in 0.5 nm increments. 2450", manufactured by Shimadzu Corporation, light source: tungsten lamp and deuterium lamp) The optical film was positioned so that the substrate side faced the light source side. The above optical film has a defect (different It must be free from foreign objects, cracks, wrinkles, and stains, and also free from curls. It was held in the spectrophotometer in a flat state. In this state, under the following measurement conditions, wavelength 380 At nm, 400nm, 410nm, and 440nm, the difference is between 1nm above and below each other. By measuring the transmittance of the lowest 5 points and calculating the average value, the wavelength 380nm is The spectral transmittance at 400 nm, 410 nm, and 440 nm was determined. The spectral transmittance at m, 400nm, 410nm, and 440nm was obtained by taking three measurements. The arithmetic mean of the given values ​​was used. (Measurement conditions) ·Wavelength range: 300nm~780nm • Scan speed: High Slit width: 2.0 • Sampling interval: Auto (0.5nm intervals) ·Lighting:C • Light source: D2 and WI ·Field of view: 2° • Light source switching wavelength: 360nm S / R switching: Standard • Pixel: PM • Auto-zero: Performed at 550nm after baseline scan.

[0259] <Yellow Index (YI)> The yellow index of the optical films according to Examples A1-A11, A13, and A15 was measured. It was decided. Specifically, first, the optical film cut to a size of 50mm x 50mm, Under conditions of 23°C and 50% relative humidity, a spectrophotometer (product name "UV-2450") was used. (Manufactured by Shimadzu Corporation; Light source: Tungsten lamp and deuterium lamp) with optical filter inside The substrate side of the film was positioned so that it faced the light source. The optical film was free of defects (impurities). It must be free of cracks, wrinkles, and stains, and also be in a flat, curl-free condition. The sample was held in a spectrophotometer. In this state, the transmittance was measured at wavelengths from 300 nm to 780 nm. Then, on the PC connected to the UV-2450, read the above transmittance measurement data. YI was obtained by checking "YI" in the calculation items. Wavelength 300nm~7 The measurement conditions for transmittance at 80 nm are the same as the measurement conditions for spectral transmittance at wavelengths such as 380 nm mentioned above. They treated it the same way.

[0260] <Total light transmittance measurement> In the optical films according to Examples A1 to A11, A13, and A15, the haze meter ( Using product name "HM-150" (manufactured by Murakami Color Technology Laboratory), at a temperature of 23°C and relative humidity The total light transmittance was measured in a 50% humidity environment according to JIS K7361:1997. Light transmittance is measured after cutting the optical film to a size of 50mm x 50mm, taking into account curling and wrinkles. The light-transmitting substrate is installed so that it faces the light source, free from fingerprints, dust, etc., and the optical frame The arithmetic mean of the values ​​obtained from three measurements per film was used.

[0261] <Haze Measurement> In the optical films according to Examples A1 to A11, A13, and A15, the haze meter ( Using product name "HM-150" (manufactured by Murakami Color Technology Laboratory), at a temperature of 23°C and relative humidity The haze value (total haze value) was measured in a 50% humidity environment according to JIS K7136:2000. Determined. The haze value was determined after cutting the optical film to a size of 50mm x 50mm. Install the light-transmitting substrate so that it faces the light source, ensuring it is free from scratches, wrinkles, fingerprints, dust, etc. The arithmetic mean of the values ​​obtained from three measurements of each optical film was used.

[0262] <Blue light blocking rate> In the optical films according to Examples A1 to A11, A13 and A15, blue light The cut rate (BL cut rate) was measured. Specifically, first, a 50mm x 50mm size was measured. The optical film cut out is measured using a spectrophotometer capable of measuring transmittance in 0.5 nm increments (product Name: "UV-2450", manufactured by Shimadzu Corporation, light source: tungsten lamp and deuterium The optical film was placed inside the lamp so that the substrate side faced the light source. The film is free from defects (impurities), cracks, wrinkles, and stains. Furthermore, it was held in the spectrophotometer in a flat state without curl. In this state, the spectral transmittance was Under the same conditions as the measurement conditions, within 1 nm before and after the wavelength range of 300 nm to 780 nm. Then, the transmittance of at least 5 points was measured. Then, the blue light cut rate was calculated from the above formula (1). The blue light cut rate was calculated using the arithmetic mean of the values ​​obtained from three measurements.

[0263] <Lightfastness Test> The optical films according to Examples A1-A11, A13, and A15 were attached to an OLED display device. Perform a lightfastness test with the material attached in layers, and measure the brightness before and after the lightfastness test. This was used to check whether the OLED display device was degrading or not. First, 50mm x 50m The optical film cut to the size of m is placed on the adhesive layer (product name "Panaclean (registered trademark) P The OLED display device (product name "Galaxy D-S1", manufactured by Panac Corporation) is transmitted via this device. It was applied to the "SII" (manufactured by Samsung). Note that the optical film is a hard coat layer. It was attached so that it was on the observer side of the light-transmitting substrate. This resulted in the light being directed towards the observer. An image display device in which an OLED display device, an adhesive layer, and an optical film are stacked in this order. I obtained it.

[0264] Then, the OLED display was turned on and the brightness was measured before the light resistance test. Brightness is measured by the image. The brightness of light emitted from the surface of the image display device (the surface of the optical film) is measured by the thickness of the image display device. From this direction, a spectroradiometer (product name "CS2000", manufactured by Konica Minolta, Inc.) was used. The measurement was then performed under conditions of a measurement angle of 1°. Next, a lightfastness tester (product name "UV fade") was used. Using a "Meter U48AU" (manufactured by Suga Test Instruments Co., Ltd.), the environment was measured at 42°C and 50% relative humidity. Below, a light resistance test was conducted by irradiating an image display device with light from a carbon arc lamp for 50 hours. Then, the image display device after the lightfastness test was turned on, and the image display device before the lightfastness test was turned on. Brightness was measured under the same conditions as for luminance measurement. Similarly, a lightfastness tester (product name "UV") was used. Using a "Line Fade Meter U48AU" (manufactured by Suga Test Instruments Co., Ltd.), at 42°C and relative humidity 5 Lightfastness to expose an image display device to light from a carbon arc lamp for 100 hours in a 0% humidity environment. A lightfastness test was conducted, and the image display device after the lightfastness test was turned on, and the image display device before the lightfastness test was turned on. The brightness was measured under the same conditions as the previous brightness measurement.

[0265] From these measured luminances, the retention rate of luminance after the lightfastness test relative to the luminance before the lightfastness test can be calculated. The following were determined. The luminance maintenance rate was defined as the luminance maintenance rate (%), and the light resistance test during illumination was performed. Let E be the surface brightness of the image display device before the test, and the image display device after the light resistance test while lit. The surface brightness was denoted as F and calculated using the following formula. D = F / E × 100

[0266] Then, based on the obtained brightness retention rate, it can be determined whether the OLED display device has deteriorated through a lightfastness test. We checked whether the OLED display was functioning correctly. Specifically, if the brightness maintenance rate is less than 60%, If the brightness is evaluated as degraded and the brightness maintenance rate is 60% or higher, the OLED display device has degraded. It was assessed as not being present. The evaluation criteria were as follows: A: No degradation of the OLED display device was detected. B: Degradation of the OLED display device was confirmed.

[0267] <Indentation hardness of the layer containing UV absorber (H IT )> In the optical films according to Examples A1 to A11, A13, and A15, an ultraviolet absorber is included. The indentation hardness of the layers was measured. Specifically, in Examples A1-A11, A13, and A In step 15, the indentation hardness of the hard coat layer containing UV absorber 1 was measured. I did. Indentation hardness (H IT ) is manufactured by HYSITRON. Measurements were taken using the TI950 TriboIndenter. Specifically, first, 1 mm A block was prepared by embedding an optical film cut to 10mm in embedding resin, A sample suitable for hardness measurement using the noindentation method was prepared. The "Ultramicrotome EM UC7" (Leica Microsystems Inc.) is used for the fabrication of the specimen. (A company) was used. Next, the surface of the sample being measured that is pressed with the indenter is level with the mounting surface of the stage. The measurement samples were placed in rows using a HYSITRON TI950 T. It was fixed to the riboIndenter stage. Then, a hard coat containing a UV absorber was applied. In the flat portion at the center of the cross-section of the layer, the maximum indentation load is 300 μN using a load control method. To achieve this, a Berkovich-type indenter is applied at a loading speed of 10 μN / sec, and the load is increased from 0 μN to 30 μN in 30 seconds. The UV absorber was pressed into the center of the cross-section of the layer while applying a load down to 0 μN, and then 30 After holding at 0 μN for 5 seconds, the load was removed from 300 μN to 0 μN over 30 seconds. The indentation depth h (nm) corresponding to the indentation load F (N) is continuously measured, and the load - A displacement curve was created. The indentation stiffness H was obtained from the created load-displacement curve. IT of As shown in equation (2) above, the maximum indentation load F max (N) includes an indenter and an ultraviolet absorber. Projection area A where the layers are in contact p (mm 2 The value was obtained by dividing by ). The value was calculated as the arithmetic mean of the values ​​obtained from measurements taken at 10 locations. p This is given by the above formula (3) That was the value that could be obtained.

[0268] <Scratch resistance test> A scratch resistance test was performed on the surface of the optical films according to Examples A1-A11, A13, and A15. I did it. Specifically, first, I cut out a piece of optical film measuring 50mm x 50mm and then... The surface is covered with a transparent adhesive layer with a film thickness of 50 μm (refractive index: 1.55, product name "Panaclean (registered trademark)"). )PD-S1, manufactured by Panac Corporation, with dimensions of 100mm x 100mm and 2mm thick acrylic sheet (product name "Comoglass DFA502K", manufactured by Kuraray Co., Ltd.) It was laminated to it. Then, #0000 steel wool (made Using product name "Bonstar" (manufactured by Nippon Steel Wool Co., Ltd.), 100g / cm³ 2 load A scratch resistance test was conducted by rubbing the optical film back and forth 10 times while applying the required material, and any scratches on the surface of the optical film were visually inspected. We observed whether or not it was approved. The evaluation results are as follows: A: No injuries were found. B: Some minor scratches were found, but they were at a level that did not affect practical use. C: The damage was clearly identified.

[0269] <Flexibility Assessment> (1) Evaluation of cracking and fracture after folding test In the optical films according to Examples A1 and A12-A16, a folding test was performed, and cracking was detected. And fracture was evaluated. Specifically, first, a length of 125 mm x 50 mm was taken from the optical film. A rectangular sample was cut out. After cutting out the sample, it was used as a folding durability tester. U-shaped expansion and contraction testing machine (product name "DLDMLH-FS", manufactured by Yuasa System Equipment Co., Ltd.) Next, the shorter side (50 mm) of this sample is fixed with the fixing part, as shown in Figure 2(C). The minimum distance between the two opposing sides is 6 mm (outer diameter of the bent part is 6 mm). Install the sample and fold the hard coat side of this sample 180° under the following conditions. The test (a test in which the hard coat layer is on the inside and the base material is on the outside) was performed 100,000 times. . (Folding conditions) • Round-trip speed: 80 rpm (cycles per minute) • Test stroke: 60mm • Bending angle: 180°

[0270] Then, we checked for cracks or fractures in the bent sections. The evaluation criteria were as follows: Furthermore, the areas of each optical film that would be bent before the folding test were observed. No cracks or fractures were observed. The evaluation criteria were as follows: (Foldable) A: No cracks or fractures occurred in the bent area even after the folding test. B: After the folding test, some cracks were found in the bent area, but this does not affect practical use. It was at that level. C: After the folding test, cracks or fractures were observed at the bending point.

[0271] Similarly, from the optical films of Examples A1, A12-A16, the same sun as above can be obtained. A pull is created, and the shorter sides of the sample are fixed with the fixing parts, and the minimum of the two opposing sides Install them so that the spacing φ is 6 mm (outer diameter of the bent part is 6 mm), on the hard coat layer side. A folding test was conducted in which the sample was repeatedly folded 180° 200,000 times so that the inner side was facing inward. Similarly, cracks and fractures in the samples after the folding test were observed and evaluated according to the above criteria. Furthermore, samples similar to those described above were prepared from the optical films relating to Examples A1 and A12-A16. The sample is prepared, and the shorter sides are fixed with the fixing parts, and the minimum distance between the two opposing sides is φ Attach it so that it is 4mm, and place the sample so that the hard coat layer side is facing inward. A folding test was performed by repeatedly folding the product 180° 0 million times, and similarly, the post-folding test results were obtained. The sample was observed for cracks and fractures and evaluated according to the above criteria.

[0272] (2) Evaluation of crease after folding test In the optical films according to Examples A1 and A12-A16, the appearance after the folding test was observed. We then assessed whether a crease had formed in the bent portion of the optical film. The folding test was as described above. The method described in the section on crack / fracture evaluation after folding test ((1) Minimum spacing φ: 6 mm) (2) Number of folds: 100,000 times, (3) Minimum spacing φ: 6 mm, Number of folds: 200,000 times, The same method was used (minimum spacing φ: 4 mm, number of folds: 200,000 times). The observation of creases was performed visually under conditions of 23°C and 50% relative humidity. In this case, use a brightly lit room with white light (800 lux to 2000 lux) and test the bent parts with transmitted light and Observe evenly using reflected light, and also observe the inner side of the bent part when folded. Both the partial and the outer parts were observed. When observing creases, the position to be observed was To facilitate easy identification, the sample before the folding test is placed in the fixed section of the U-shaped extension test machine. And when folded once, as shown in Figure 3, the bending portion is perpendicular to the folding direction. I marked both ends, which are located in the direction of the curve, with an oil-based pen to indicate that they are bent sections. After the folding test, the bending part was removed from the U-shaped stretch test machine after the folding test. I drew a line with an oil-based pen connecting the two marks at both ends mentioned above. Then, I observed the creases from folding. The bent portion is the region formed by the marks at both ends of the bent portion and the line connecting these marks. The entire structure was visually inspected. Note the area of ​​each optical film that will be bent before the folding test. Upon observation, no creases were observed. The evaluation criteria were as follows: A: No creases were observed in the optical film even after the folding test. B: After the folding test, some creases were observed in the optical film, but this does not affect practical use. It was at a level that was beyond reproach. C: After the folding test, creases were observed in the optical film.

[0273] (3) Microcrack evaluation after folding test In the optical films according to Examples A1 and A12-A16, the appearance after the folding test was observed. We then assessed whether microcracks had formed in the bent portion of the optical film. The test is conducted using the method described in the section on crack / fracture evaluation after the folding test (minimum spacing φ: 6 The same method was used (mm, number of folds: 100,000). Microcrack observation The observation was conducted in an environment with a temperature of 23°C and a relative humidity of 50%, using a digital microscope (product name The procedure was performed using the "VHX-5000" (manufactured by Keyence Corporation). Specifically, first, folding Slowly unfold the sample after the folding test and tape it onto the microscope stage. The fold was fixed in place. At this time, if the crease is strong, try to make the observation area as flat as possible. However, do not touch the area near the center of the sample that is intended for observation (the curved part) with your hands, and do not apply any force to it. To a certain extent. Next, observe both the inner and outer parts when folded. For observing microcracks, ring illumination was used as the light source for the digital microscope. Selected areas were examined at 200x magnification using dark-field and reflected light. Observation of microcracks was performed using odor control. Therefore, to make it easy to identify the position to be observed, the sample before the folding test is stretched in a U-shape. When installed in the fixed part of the testing machine and folded once, as shown in Figure 3, at the bent part Mark both ends, located perpendicular to the folding direction, with an oil-based pen to indicate the bends. I attached it. Also, after the folding test, it was removed from the U-shaped extension test machine. With that in place, I drew a line with an oil-based pen connecting the two marks at both ends of the bent section. When observing microcracks, the center of the microscope's field of view should be the center of the bend. The microscope was positioned accordingly. When the areas of the film that are bent were observed, no microcracks were found. The evaluation criteria were as follows: (Microcracks) A: No microcracks were observed in the optical film even after the folding test. . B: After the folding test, some microcracks were observed in the optical film, It was at a level that did not pose any problems in practical use. C: Microcracks were observed in the optical film after the folding test.

[0274] The results are shown in Tables 2 to 5 below. [Table 2]

[0275] [Table 3]

[0276] [Table 4]

[0277] [Table 5]

[0278] As shown in Table 2, the optical films relating to Comparative Examples A1, A2, and A5 have durability Even before the test, delamination occurred at the interface between the substrate layer and the hard coat layer, indicating poor adhesion before the durability test. (Initial adhesion) was poor. In addition, in the optical film relating to Comparative Example A3, initial Adhesion was good, but adhesion was poor after the durability test. Furthermore, regarding Comparative Example A4... In the case of optical films, the pencil hardness is inferior, and in the case of the optical film relating to Comparative Example A6... However, it was inferior in terms of visibility evaluation. In contrast, the optical films of Examples A1 to A16 In this case, prior to the durability test, the adhesion (initial adhesion) was good. This is a mixture containing the components of the substrate and the hard coat between the substrate and the hard coat layer. A layer is formed, and the total film thickness of the base layer, mixed layer and hard coat layer is This is thought to be because the film thickness ratio of the mixed layer was 0.6% or more. Also, Example A 1. For optical films related to A3-A7 and A9-A16, not only before the durability test, Adhesion after durability testing was also good. This is due to the combination of the substrate layer, mixed layer, and hard coat layer. This is thought to be because the ratio of the thickness of the mixed layer to the total thickness was 1% or more. In the optical films according to Examples A1 to A16, excellent pencil hardness was observed. This is because The ratio of the thickness of the mixed layer to the total thickness of the base layer, mixed layer, and hard coat layer is 40%. This is thought to be because the following occurred. Furthermore, the optical films relating to Examples A1 to A16 In this regard, it performed well in visibility evaluation. This is because, as a light-transmitting substrate, cycloolefin poly Because they were using a rimer-based substrate, a triacetylcellulose substrate, or an acrylic resin substrate. It is thought that this is the case.

[0279] <<Example B and Comparative Example B>> <Example B1> (Preparation of composition 3 for hard coat layer) Pentaerythritol triacrylate and pentaerythritol tetraacrylate Mixture (product name "KAYARAD PET-30", manufactured by Nippon Kayaku Co., Ltd.) and examples Mix the above acrylic polymer 1 described in column A1 in a solids mass ratio of 20:80. Dilute with solvent (methyl ethyl ketone and toluene in a mass ratio of 80:20) to a concentration of 25%. A resin composition was prepared. Then, polymerization was initiated in 160 parts by mass of the obtained resin composition. Agents (Omnirad184 and Omnirad8 manufactured by IGM Resins BV) 19 (mass ratio 50:50) 4 parts by mass and leveling agent (product name "F568", DIC Corporation) Mix 0.2 parts by mass of (manufactured by the company) with the mixture and stir well to prepare hard coat layer composition 3. did.

[0280] (Preparation of composition 4 for hard coat layer) Urethane acrylate resin (product name "Beamset 577", Arakawa Chemical Industries, Ltd.) (Manufactured) up to 50% solids content, solvent (methyl ethyl ketone and methyl isobutyl ketone, The resin composition was prepared by diluting it in a volume ratio of 50:50. Then, the obtained resin composition 20 Per 0 parts by mass, a polymerization initiator (Omnirad18 from IGM Resins BV) 4) 4 parts by mass and 0.2 parts by mass of leveling agent (product name "F568", manufactured by DIC Corporation) And silica nanoparticles (product name "SIRMIBK-E65", manufactured by CIK Nanotech Co., Ltd.) ) Mixed with 3 parts by mass and thoroughly stirred to prepare hard coat layer composition 4. .

[0281] (Production of optical films) The above hard coat layer composition 3 is prepared at Miyabar in a size of 210 mm x 297 mm (A 4 sizes) and a triacetylcellulose-based substrate with a thickness of 25 μm (product name "Fujitac") The first coating was formed by applying it to the surface of "TJ25UL" (manufactured by Fujifilm Corporation). Then, dry air at 50°C is flowed over the formed coating film at a flow rate of 0.5 m / s for 30 seconds. By doing so, the solvent in the first coating film is evaporated, and the accumulated ultraviolet light intensity reaches 120 mJ / cm². 2 to The first coating was partially cured by irradiating it in the desired manner.

[0282] After forming the semi-cured first coating film, a hard coat layer is applied to the surface of the first coating film using Miyaba. Composition 4 was applied to form a second coating film. Then, 0.5 By circulating 70°C dry air at a flow rate of m / s for 30 seconds, the solvent in the coating film is evaporated. Furthermore, when ultraviolet light is applied in a nitrogen atmosphere (oxygen concentration of 200 ppm or less), the cumulative light intensity is 200 mJ / cm². 2 By irradiating the first and second coating films in such a manner, the hardened film thickness is obtained. A hard coating with a thickness of 6 μm, consisting of a first coating film of 3 μm thickness and a second coating film with a cured thickness of 3 μm. A hard coat layer was formed. This provides a hard coat layer on the triacetylcellulose substrate. An optical film was obtained.

[0283] The thickness of the hard coat layer was determined by the same method as the thickness of the undercoat layer described in Example A1. Measurement shall be performed accordingly. In addition, in Examples B2 to B11 and Comparative Examples B1 to B6, The thickness of the hard coat layer was measured using the same method as in Example B1.

[0284] <Example B2> In Example B2, instead of composition 3 for the hard coat layer, the composition for the hard coat layer An optical film was obtained in the same manner as in Example B1, except that material 5 was used.

[0285] (Composition for hard coat layer 5) Dicyclopentenyl acrylate (product name "FA-511AS", manufactured by Hitachi Chemical Co., Ltd.) ) and the above acrylic polymer 1 are mixed in a solids mass ratio of 20:80, resulting in a solids content of 25%. Dilute with a solvent (methyl ethyl ketone and toluene in a mass ratio of 80:20) and mix with resin. The product was prepared. Next, 160 parts by mass of the obtained resin composition was mixed with a polymerization initiator (IGM). Mass of Omnirad184 and Omnirad819 manufactured by Resins BV (Ratio 50:50) 4 parts by mass and leveling agent (product name "F568", manufactured by DIC Corporation) 0 Mix 0.2 parts by mass with the other and stir well to prepare hard coat layer composition 5.

[0286] <Example B3> In Example B3, instead of a 6 μm thick hard coat layer, a cured 1 μm thick layer was used. A hard coat layer with a thickness of 2 μm is formed, consisting of a first coating film and a hardened second coating film with a thickness of 1 μm. An optical film was obtained in the same manner as in Example B1, except for the difference mentioned above.

[0287] <Example B4> In Example B4, instead of a 6 μm thick hard coat layer, a cured 5 μm thick layer was used. A hard coat layer with a thickness of 10 μm is formed, consisting of a first coating film and a hardened second coating film with a thickness of 5 μm. An optical film was obtained in the same manner as in Example B1, except for the actions taken.

[0288] <Example B5> In Example B5, a triacetylcellulose-based substrate with a thickness of 25 μm (product name "Fuji") was used. Instead of "Tack TJ25UL" (manufactured by Fujifilm Corporation), use a 60μm thick triacetate film. Chilled cellulose base material (product name "Fujitac TD60UL", manufactured by Fujifilm Corporation) An optical film was obtained in the same manner as in Example B1, except for the materials used.

[0289] <Example B6> In Example B6, instead of a triacetylcellulose substrate, a 50 μm thick cellulose Croolefin polymer-based substrate (product name "Zeonor Film (registered trademark) ZF14-05") The material (manufactured by Zeon Corporation) is stretched at 150°C to achieve an in-plane phase difference of 100 nm. By using a cycloolefin polymer substrate with a thickness of 25 μm produced by the following method... The optical film was obtained in the same manner as in Example B1.

[0290] <Example B7> In Example B7, instead of a triacetylcellulose-based substrate, a 50 μm thick cellulose was used. Croolefin polymer-based substrate (product name "Zeonor Film (registered trademark) ZF14-05") Except for using "0" (manufactured by Nippon Zeon Co., Ltd.), the optical filter was used in the same manner as in Example B1. I obtained the Mu.

[0291] <Example B8> In Example B8, instead of a triacetylcellulose substrate, a 30 μm thick a Acrylic resin substrate (product name "OXIS(registered trademark)-ZU (30μm)", Okura Industries Co., Ltd.) An optical film was obtained in the same manner as in Example B1, except that a (company-made) product was used.

[0292] <Example B9> In Example B9, instead of a triacetylcellulose-based substrate, a 40 μm thick a Acrylic resin substrate (product name "OXIS(registered trademark)-ZU (40μm)", Okura Industries Co., Ltd.) An optical film was obtained in the same manner as in Example B1, except that a (company-made) product was used.

[0293] <Example B10> In Example B10, instead of a triacetylcellulose-based substrate, the following method was used A polyethylene terephthalate substrate (PET substrate, in-plane phase) with a thickness of 40 μm was fabricated using this method. Except for using a difference Re: 600 nm and an Nz coefficient of 20, the same procedure as in Example B1 was used for light emission. I obtained a film.

[0294] (Preparation of PET substrate) First, 1 kg of PET (melting point 258°C, absorption center wavelength: 320 nm) and 0.1 kg of UV absorber (2,2'-(1,4-phenylene)bis(4H-3,1-benzoxadi Non-4-on is melted and mixed in a kneader at 280°C, and pellets containing an ultraviolet absorber are formed. A pellet was prepared. This pellet, along with PET with a melting point of 258°C, was fed into a single-screw extruder, and 280°C was produced. The mixture is melted and kneaded at °C, extruded from a T-die, and then cast onto a cast drum with a controlled surface temperature of 25°C. Casting was performed to obtain a casting film. The UV absorber in the casting film The amount was 1 part by mass per 100 parts by mass of PET.

[0295] The obtained casting film was heated in a group of rolls set to 95°C, and then stretched. 400mm apart (the starting point is stretching roll A, and the ending point is stretching roll B, and stretching rolls A and B The film temperature at the 150mm point (each having two nip rolls) is 10 To maintain a temperature of 3°C, turbulence is generated from both sides of the film using a radiation heater. The film was stretched 3.5 times in the flow direction while being heated, and then cooled.

[0296] Next, corona discharge treatment is performed on both sides of this uniaxially oriented film in air, and the base film The wetting tension is set to 55 mN / m, and the corona discharge treated surfaces on both sides of the film have a glass transition temperature of 1 Polyester resin with a glass transition temperature of 8°C, polyester resin with a glass transition temperature of 82°C, and average particle size 1 A smooth-slip coating solution containing 00nm silica particles is applied in-line to form a smooth-slip layer. Ta.

[0297] Next, the uniaxially oriented film is guided into the tenter, preheated with 95°C hot air, and then the first stage is set to 105°C. The second stage involved stretching the film 3.8 times in the width direction at a temperature of 140°C. Here, the transverse stretching section was divided into two sections. When divided, the amount of film stretching at the midpoint of the lateral stretching section (film width at the measurement point - The film width before stretching is stretched in two stages so that it becomes 80% of the stretch amount at the end of the lateral stretching section. The horizontally stretched film was then subjected to a heat treatment process in a tenter, gradually increasing the temperature from 180°C to 2°C. The material is heat-treated with hot air at 45°C, followed by a 1% relaxation treatment in the width direction under the same temperature conditions, and further... After rapid cooling to 100°C, a 1% relaxation treatment is applied in the width direction, followed by winding and biaxial stretching. A PET substrate was obtained.

[0298] <Example B11> In Example B11, instead of a triacetylcellulose-based substrate, a 100 μm thick material was used. Polyethylene terephthalate substrate (product name "Cosmoshine (registered trademark) A4100") An optical film was obtained in the same manner as in Example B1, except that a (manufactured by Toyobo Co., Ltd.) product was used. .

[0299] <Comparative Example B1> The above hard coat layer composition 3 is prepared at Miyabar in a size of 210 mm x 297 mm (A 4 sizes) and a triacetylcellulose-based substrate with a thickness of 25 μm (product name "Fujitac") The coating was applied to the surface of "TJ25UL" (manufactured by Fujifilm Corporation) to form a coating film. Then, dry air at 50°C is circulated over the formed coating film at a flow rate of 0.5 m / s for 30 seconds. This evaporates the solvent in the coating film, and ultraviolet light is applied in a nitrogen atmosphere (oxygen concentration of 200 ppm or less). The accumulated light intensity was 500 mJ / cm². 2 The coating was cured by irradiating it in such a way. An optical film comprising a hard coat layer with a thickness of 6 μm on a triacetylcellulose substrate. I obtained the Mu.

[0300] <Comparative example B2> In Comparative Example B2, hard coat layer composition 3 is replaced with hard coat layer composition An optical film was obtained in the same manner as in Comparative Example B1, except that 5 was used.

[0301] <Comparative Example B3> In Comparative Example B3, instead of hard coat layer composition 3, hard coat layer composition Using 4, and using hard coat layer composition 3 instead of hard coat layer composition 4. An optical film was obtained in the same manner as in Example B1, except for the above.

[0302] <Comparative example B4> In Comparative Example B4, when curing the first coating film, ultraviolet light was used in a nitrogen atmosphere (oxygen concentration 20%). (0 ppm or less) Integrated light intensity of 400 mJ / cm 2 Other than the fact that it was irradiated in such a way, An optical film was obtained in the same manner as in Example B1.

[0303] <Comparative Example B5> In Comparative Example B5, instead of hard coat layer composition 3, hard coat layer composition Using 4, and using hard coat layer composition 5 instead of hard coat layer composition 4. An optical film was obtained in the same manner as in Example B1, except for the above.

[0304] <Comparative example B6> First, the following hard coat layer composition 6 was prepared. (Composition for hard coat layer 6) Tricyclodecane dimethanol diacrylate (product name "A-DCP", Shin Nakamura Chemical Co., Ltd.) Mix the above acrylic polymer 1 (manufactured by Gyo Co., Ltd.) and the above acrylic polymer 1 in a solid content mass ratio of 20:80. Dilute to 25% solids content with a solvent (methyl ethyl ketone and toluene in a mass ratio of 80:20). The resin composition was prepared by dissolving the polymer. Then, 160 parts by mass of the obtained resin composition was subjected to polymerization. Initiator (Omnirad184 manufactured by IGM Resins BV and BASF Japan) IRGACURE(registered trademark) OXE01 manufactured by [company name] (mass ratio 50:50) 4 parts by mass, and Add 0.2 parts by mass of a bearing agent (product name "F-568", manufactured by DIC Corporation) and mix well. The mixture was stirred to prepare composition 6 for the hard coat layer.

[0305] After preparing the hard coat layer composition 6, the hard coat layer composition 6 is prepared at Miyaba. The triacetyl cellulose is 210mm x 297mm (A4 size) and 25μm thick. Surface of lurose-based substrate (product name "Fujitac TJ25UL", manufactured by Fujifilm Corporation) It was applied to form a coating film. Then, the formed coating film was subjected to a flow rate of 0.5 m / s. By flowing dry air at 0°C for 30 seconds, the solvent in the coating film was evaporated, and ultraviolet rays were irradiated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) so that the integrated light quantity reached 400 mJ / cm 2 to cure the coating film and form a first cured coating film with a film thickness of 3 μm. After forming the cured first coating film, the composition 4 for the hard coat layer was applied

[0306] onto the surface of the first coating film to form a second coating film. Next, with respect to the formed second coating film, dry air at 50°C was flowed at a flow rate of 0.5 m / s [[ID=Il]] for 30 seconds to evaporate the solvent in the second coating film, and ultraviolet [[ID=1s]] rays were irradiated in a nitrogen atmosphere (oxygen concentration of <200 ppm) so that the integrated light quantity reached 200 mJ / cm to cure the second coating film and form a second cured coating film with a film thickness of 3 μm. Thus, an optical film having a hard coat layer with a film thickness of 6 μm composed of the cured first coating film and the cured second coating film 2 was obtained on the triacetyl cellulose-based substrate. When observing whether an interface exists in the hard coat layer using a scanning transmission electron microscope (STEM) at this time, an interface was observed between the first hard coat layer and the second hard coat layer. <Measurement of the intensity of components in the hard coat layer by TOF-SIMS> In the optical films according to Examples B1 to B11 and Comparative Examples B1 to B6, a time-of-flight secondary ion mass spectrometer (product name "TOF.SIMS5", manufactured by ION-TOF) was used to measure the intensity of secondary ions derived from each component in the hard coat layer. Specifically, first, an optical film cut out to a size of 10 mm × 10 mm was placed in the sample chamber of the time-of-flight secondary ion mass spectrometer so that primary ions were irradiated onto the surface of the hard coat layer. After that

[0307] <TOF-SIMSによるハードコート層中の成分の強度測定> In the optical films according to Examples B1 to B11 and Comparative Examples B1 to B6, a time-of-flight secondary ion mass spectrometer (product name "TOF.SIMS5", manufactured by ION-TOF) was used to measure the intensity of secondary ions derived from each component in the hard coat layer. Specifically, first, an optical film cut out to a size of 10 mm × 10 mm was placed in the sample chamber of the time-of-flight secondary ion mass spectrometer so that primary ions were irradiated onto the surface of the hard coat layer. After that 装置の試料室に一次イオンがハードコート層の表面に照射されるように設置した。その後 The intensity of secondary ions derived from each component was measured under the following measurement conditions, and the depth profile was obtained. Obtained. And from this depth profile, the hard coat layer in the depth direction Identify the bisector line that divides the layer in two and the back surface of the hard coat layer, and the front surface of the hard coat layer The first region has a thickness of 0.3 μm and the hard coat layer is divided into two equal parts in the depth direction of the hard coat layer. A second region with a thickness of 0.3 μm containing the bisector, and a thickness of 0. From the boundary between the 3 μm third region and the first region on the triacetylcellulose substrate side, hard coating The fourth region, extending to the back surface of the layer, was determined. Then, the ultraviolet absorption in the first to third regions was determined. Intensity I of secondary ions derived from agent 1 U1 , I U2 , I U3 , secondary ions derived from fluorine-containing compounds Strength of I F1 , I F2 , I F3 , and the intensity I of secondary ions derived from silicon-containing compounds S 1. I S2 , I S3 Determine the intensity ratio I U2 / I U1 , I U3 / I U2 , I U3 / I U1 , I F1 / I F2 , I F1 / I F3 , I S1 / I S2 , I S1 / I S3 They sought purple. The secondary ions derived from the external radiation absorber 1 are C6H4N3. - Acrylic acid esters and acetate compounds The derived secondary ion is C2H3O2 - Therefore, secondary ions derived from fluorine-containing compounds are F - year SiO2 as a secondary ion derived from silicon-containing compounds - It was also stated that organic matter containing nitrogen As a secondary ion derived from CN - The strength was measured. Also, the back of the hard court layer was deep C2H, a secondary ion derived from acrylic acid esters and acetate compounds in Sprofile. 3O2 - and C6H4N3, a secondary ion derived from UV absorber 1 - This was the position of the intersection point. Furthermore, the second region was set up so that its bisector lies in the center of the second region. (Measurement conditions) • Secondary ion polarity: Negative ·Mass range (m / z): 0~3000 • Raster size: 200μm□ • Scan rate: 1 scan / cycle • Pixel count (per side): 128 pixels • Measured vacuum level (before sample introduction): 4 × 10 -7 Pa or less • Neutralization of static charge: Yes ·Late acceleration: 10kV • Primary ion: Bi3 ++ • Primary ion acceleration voltage: 30kV Pulse width: 11.3ns • Bunching: Yes (High-mass-resolution measurement) • Etching ions: Ar gas cluster ion beam (Ar-GCIB) • Etching ion acceleration voltage: 20kV • Ar cluster size (median): approximately 1400

[0308] <Pencil hardness> Surface (hard coat) of optical films in Examples B1-B11 and Comparative Examples B1-B6 The pencil hardness was measured on the surface of each layer. The pencil hardness test was performed on a 50mm x 100m sheet. A pencil hardness tester (product name "Pencil Hardness Tester") is used to test the surface of an optical film cut to a size of m. Using a "Hardness Tester (Electric Type)" (manufactured by Toyo Seiki Seisakusho Co., Ltd.), the hardness of the coating film was tested at a temperature of approximately 23°C. And in an environment with a relative humidity of 50% or less, a pencil (product name "Uni", manufactured by Mitsubishi Pencil Co., Ltd.) was subjected to 30 This shall be performed by moving the object at a speed of 3 mm / second while applying a load of 0 g. The pencil hardness is the highest level in which no scratches were left on the surface of the optical film 10 during the pencil hardness test. This was defined as hardness. Note that when measuring pencil hardness, multiple pencils with different hardness levels are used. Each pencil was subjected to a pencil hardness test five times, and if it was found to have a scratch on the surface of the optical film in four or more of those five tests... If it did not happen, it means that the surface of the optical film was not scratched by a pencil of this hardness. I concluded that this was the case.

[0309] <Scratch resistance test> Surface (hard coat) of optical films in Examples B1-B11 and Comparative Examples B1-B6 Scratch resistance tests were conducted on the surface of the layer under conditions of 23°C and 50% relative humidity. Specifically, first, on the surface of an optical film cut to a size of 50mm x 50mm In contrast, #0000 steel wool (product name "Bonstar", Japan Steel Wool Co., Ltd.) Using (company-made) 100g / cm³ 2 A scratch resistance test was conducted by rubbing the surface back and forth 10 times while applying a load. We observed whether or not scratches could be found on the surface of the optical film by visual inspection. The evaluation results are as follows: I followed the rules. A: No injuries were found. B: Some minor scratches were found, but they were at a level that did not affect practical use. C: The damage was clearly identified.

[0310] <Durability Test> In the optical films of Examples B1 to B11 and Comparative Examples B1 to B6, durability tests were performed. Yes, I did. Specifically, I cut out optical film to a size of 100mm x 100mm and used it to make durable It is placed inside the test apparatus (product name "Constant Temperature and Humidity Chamber PL-1KP", manufactured by ESPEC Corporation), A durability test was conducted by leaving the device for 240 hours under conditions of 85°C and 85% relative humidity. The film must be free of defects (foreign matter), cracks, wrinkles, and stains. It was also placed in the durability testing apparatus in a flat, curl-free state.

[0311] After durability testing, under conditions of 23°C and 50% relative humidity, the hard coat layer surface was subjected to deposition. We evaluated whether there were any protrusions and whether there were cracks in the hard court layer. The criteria were as follows: A: Neither precipitates nor cracks were found. B: Either precipitates or cracks were observed. C: Both the presence of precipitates and cracks were confirmed.

[0312] <Spectral transmittance> In the optical films according to Examples B1-B4, B6, B8, and B10, the temperature was 23°C and And in an environment with a relative humidity of 50%, wavelengths of 380nm, 400nm, 410nm, and 440nm The spectral transmittance at nm was determined using the same method as described in the section for Example A and the same Measurements were taken under the specified conditions.

[0313] <Yellow Index (YI)> The yellow index of the optical film relating to Examples B1-B4, B6, B8, and B10 is Using the same method and measurement conditions as described in the Yellow Index section of Example A It was measured.

[0314] <Total light transmittance measurement> In the optical films according to Examples B1-B4, B6, B8, and B10, the haze meter Using (product name "HM-150", manufactured by Murakami Color Technology Laboratory), at a temperature of 23°C and relative humidity The total light transmittance was measured in an environment with 50% humidity, according to JIS K7361:1997. Specifically, the total light transmittance is calculated using the same method as described in the section for Example A. The measurements were taken under the same conditions.

[0315] <Haze Measurement> In the optical films according to Examples B1-B4, B6, B8, and B10, the haze meter Using (product name "HM-150", manufactured by Murakami Color Technology Laboratory), at a temperature of 23°C and relative humidity Under conditions of 50% humidity, the haze value (total haze value) was measured according to JIS K7136:2000. Measurements were taken. Specifically, the total light transmittance was measured in the same way as the haze value described in the section for Example A. Measurements were taken using the law and similar measurement conditions.

[0316] <Visibility Evaluation> In the optical films according to Examples B1-B4, B6, B8, and B10, visibility was evaluated. Specifically, the visibility evaluation was carried out using the same method as the visibility evaluation described in the section for Example A. They were evaluated using the same criteria.

[0317] <Flexibility Assessment> (1) Evaluation of cracking and fracture after folding test In the optical films according to Examples B1 and B5-B11, a folding test was performed and cracking occurred. The fracture was evaluated. Specifically, the folding test was performed on the crack after the folding test in Example A. The folding test described in the fracture evaluation section was performed using the same method and under the same measurement conditions. Furthermore, the cracking and fracture evaluation is described in the section for the cracking and fracture evaluation after the folding test in Example A. The evaluation was conducted using the same evaluation method and criteria.

[0318] (2) Evaluation of crease after folding test In the optical films according to Examples B1 and B5-B11, the appearance after the folding test was observed. Then, we evaluated whether creases had formed in the bent parts of the optical film. Specifically, we performed a folding test. The test was conducted in the same manner as the folding test described in the section on evaluating crease after the folding test in Example A. The measurements were performed using the same method and under similar measurement conditions. Furthermore, the fold crease evaluation was performed after the folding test in Example A. The evaluation was conducted using the evaluation method and similar criteria described in the section on fold crease evaluation.

[0319] (3) Microcrack evaluation after folding test In the optical films according to Examples B1 and B5-B11, the appearance after the folding test was observed. Then, we evaluated whether microcracks had formed in the bent portion of the optical film. Specifically, The folding test is described in the section on microcrack evaluation after the folding test in Example A. The same method and measurement conditions as in the folding test were used. Microcrack evaluation was also performed. This refers to the evaluation method described in the section on microcrack evaluation after the folding test in Example A, and They were evaluated using the same criteria.

[0320] The results are shown in Tables 6 to 9 below. Also, Figure 15 shows the optical film related to Example B1. The depth profile, measured by time-of-flight secondary ion mass spectrometry, is shown. [Table 6]

[0321] [Table 7]

[0322] [Table 8]

[0323] [Table 9]

[0324] As shown in Table 6, in the optical films relating to Comparative Examples B1 to B6, I U2 / I U1 If it is outside the range of 1.1 to 4.0, or I U3 / I U2 1.2 or higher, 4.0 Because it was outside the following range, it was inferior in pencil hardness, scratch resistance, and durability. In the optical films relating to Examples B1 to B11, I U2 / I U1 1.1 or higher, or 4. It is less than or equal to 0, and I U3 / I U2 Since the value was between 1.2 and 4.0, we aimed to make it thinner. Furthermore, good pencil hardness, good scratch resistance, and good durability were achieved. CN as a secondary ion derived from nitrogen-containing organic matter - The strength of C6H4N3 - The same strength The following results were obtained. Also, from the graph in Figure 15, the UV absorber 1 in the first region was found to be derived The minimum intensity of secondary ions is from the boundary on the triacetylcellulose substrate side of the first region to the back surface. This is smaller than the minimum intensity of secondary ions derived from UV absorber 1 in the fourth region up to this point. I understand. [Explanation of Symbols]

[0325] 10, 100… Optical film 10A…Surface 11, 101...Light transparent base material 12…1st functional layer 13...Second functional layer 14…Mixed layer 21…First coating 22...Second coating 30…Polarizing plate 31… Polarizer 40, 130… Image display device 50…Display element 102… Functional Layer

Claims

1. An optical film comprising a light-transmitting substrate, a first functional layer, and a second functional layer in this order, The light-transmitting substrate comprises at least one of an acetylcellulose resin, a cycloolefin polymer resin, and a (meth)acrylic resin. Both the first functional layer and the second functional layer contain an ultraviolet absorber. The present invention further comprises a mixed layer provided between the first functional layer and the second functional layer, adjacent to the first functional layer and the second functional layer, and containing components of the first functional layer and the second functional layer, The total film thickness of the first functional layer, the second functional layer, and the mixed layer is 1 μm or more and 10 μm or less. The ratio of the film thickness of the mixed layer to the total film thickness of the first functional layer, the second functional layer, and the mixed layer is 0.6% or more and 40% or less. The second functional layer is a hard coat layer, The indentation stiffness of the second functional layer is greater than the indentation stiffness of the first functional layer. The blue light blocking rate is 20% or more. When the shielding rate is A, the average value (%) of the transmittance in the optical film at wavelengths from 380 nm to 500 nm is B, and the average value (%) of the transmittance in the optical film at wavelengths from 500 nm to 650 nm is C, the shielding rate can be calculated by the following formula (1): A={1-(B / C)}×100...(1) An optical film having a spectral transmittance of 6.4% or less at a wavelength of 410 nm.

2. An optical film comprising a light-transmitting substrate, a first functional layer, and a second functional layer in this order, The light-transmitting substrate comprises at least one of an acetylcellulose resin, a cycloolefin polymer resin, and a (meth)acrylic resin. Both the first functional layer and the second functional layer contain an ultraviolet absorber. The present invention further comprises a mixed layer provided between the first functional layer and the second functional layer, adjacent to the first functional layer and the second functional layer, and containing components of the first functional layer and the second functional layer, The total film thickness of the first functional layer, the second functional layer, and the mixed layer is 1 μm or more and 10 μm or less. The thickness of the mixed layer is 0.02 μm or more and 1 μm or less. The second functional layer is a hard coat layer, The indentation stiffness of the second functional layer is greater than the indentation stiffness of the first functional layer. The blue light blocking rate is 20% or more. When the shielding rate is A, the average value (%) of the transmittance in the optical film at wavelengths from 380 nm to 500 nm is B, and the average value (%) of the transmittance in the optical film at wavelengths from 500 nm to 650 nm is C, the shielding rate can be calculated by the following formula (1): A={1-(B / C)}×100...(1) An optical film having a spectral transmittance of 6.4% or less at a wavelength of 410 nm.

3. The optical film according to claim 1 or 2, wherein the thickness of the mixed layer is 0.1 μm or more.

4. The optical film according to any one of claims 1 to 3, wherein the indentation hardness of the first functional layer is 50 MPa or more and 600 MPa or less.

5. The optical film according to any one of claims 1 to 4, wherein the indentation hardness of the second functional layer is 75 MPa or more and 1000 MPa or less.

6. The optical film according to any one of claims 1 to 5, wherein the spectral transmittance at a wavelength of 380 nm is less than 10%.

7. The optical film according to any one of claims 1 to 6, wherein the spectral transmittance at a wavelength of 440 nm is 75% or more.

8. The optical film according to any one of claims 1 to 7, wherein the yellow index is 15 or less.

9. An optical film according to any one of claims 1 to 8, wherein the total light transmittance is 80% or more.

10. An optical film according to any one of claims 1 to 9, A polarizer provided on one side of the optical film, A polarizing plate equipped with a polarizing plate.

11. Display element and An optical film according to any one of claims 1 to 9 or a polarizing plate according to claim 10, which is positioned on the observer side of the display element, An image display device equipped with the following features.

12. The image display device according to claim 11, wherein the display element is an organic light-emitting diode element.

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