Optical film, polarizer, and image display device

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 an optical film, a polarizing plate, and an image display device. [Background technology]

[0002] In recent years, smartphones that use organic light-emitting diode (OLED) elements as display elements have become more common. The development of image display devices such as the above is progressing. Image display devices using organic light-emitting diode elements are Unlike a non-emissive display device such as a liquid crystal display device, the display device is a self-emissive display device. Since no light source such as a backlight is required, it is possible to make the display thinner and lighter. be.

[0003] On the other hand, OLED elements can deteriorate due to ultraviolet rays, so they are not incorporated into image display devices. The adhesive layer and other functional layers of the optical film embedded in the product contain ultraviolet absorbing agents. (For example, see Patent Documents 1 and 2).

[0004] In addition, Patent Document 2 discloses a method for forming a cured layer containing an ultraviolet absorbing agent on a cured layer containing an ultraviolet absorbing agent. An overcoat layer is provided that is free of ultraviolet absorbing agents or has a lower content of ultraviolet absorbing agents than the cured layer. It is disclosed that: [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-155213 A [Patent Document 2] JP 2016-200709 A Summary of the Invention [Problem to be solved by the invention]

[0006] Currently, there is a demand for image display devices to be made thinner. There is also a demand for thinner optical films incorporated in the device. In addition, efforts are being made to reduce the thickness of the functional layers of optical films.

[0007] However, simply reducing the thickness of the functional layer increases the concentration of the ultraviolet absorbing agent in the functional layer. The reaction rate of the polymerizable compound that is polymerized by ultraviolet light to form the functional layer becomes Therefore, the functional layer containing the ultraviolet absorbing agent and other functional layers adjacent to this functional layer are The adhesion to the coating layer is reduced.

[0008] In addition, simply reducing the thickness of the functional layer increases the concentration of the UV absorber in the functional layer. This may result in a decrease in the surface hardness and scratch resistance of the functional layer. If the scratch resistance decreases, scratches are more likely to occur during processing.

[0009] In addition, when the concentration of the UV absorber in the functional layer becomes high, the UV absorber becomes more likely to precipitate. , durability may decrease.

[0010] In addition, as in Patent Document 2, two functional layers such as a hardening layer and an overcoat layer are laminated. When the total thickness of the functional layers is thin, the UV radiation between these two layers is extremely strong. If there is a difference in the concentration of the UV absorber, the functional layer containing a large amount of UV absorber and the UV Cracks may occur due to the difference in thermal contraction between the functional layer having less radiation absorbent.

[0011] The present invention has been made to solve the above problems. and improving the adhesion between the first functional layer and the second functional layer. Another object of the present invention is to provide a polarizing plate and an image display device that include such an optical film. do.

[0012] In addition, it is possible to achieve a thin film and have good surface hardness, good scratch resistance and good durability. Optical film having durability, polarizing plate and image display device including such optical film - Patents.com The purpose is to provide. [Means for solving the problem]

[0013] The present 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 made of a triacetyl cellulose-based resin, a cycloolefin polymer, and (meth)acrylic resin, and At least one of the first functional layer and the second functional layer contains an ultraviolet absorbing agent. a second functional layer, adjacent to the first functional layer and the second functional layer, The composition further comprises a mixed layer including a component of the first functional layer and a component of the second functional layer, the total thickness of the first functional layer, the second functional layer and the mixed layer is 1 μm or more and 10 μm or less; a ratio of a thickness of the mixed layer to a total thickness of the first functional layer, the second functional layer and the mixed layer; The optical film has a ratio 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. At least one of the first functional layer and the second functional layer contains an ultraviolet absorbing agent. a first functional layer and a second functional layer, a mixed layer adjacent to the functional layer and including a component of the first functional layer and a component of the second functional layer; In addition, the total thickness of the first functional layer, the second functional layer and the mixed layer is 1 μm or more. 10 μm or less, and the thickness of the mixed layer is 0.02 μm or more and 1 μm or less. Film.

[0015] [3] The mixed layer is a first layer including at least a polymerizable compound on one surface of the light-transmitting substrate. A first coating film of a composition for a functional layer is applied to form a first coating film, the first coating film is semi-cured, and semi-cured. A second coating film of a composition for a second functional layer containing at least a polymerizable compound on the cured first coating film. and curing the first coating film and the second coating film. [1] or [2]. An optical film according to the present invention.

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

[0017] [5] The above, wherein both the first functional layer and the second functional layer contain the ultraviolet absorber. [1] The optical film according to any one of [1] to [4].

[0018] [6] The first functional layer contains the ultraviolet absorber, and an indentation of the first functional layer The optical film according to the above [1], having a hardness of 50 MPa or more and 600 MPa or less.

[0019] [7] An optical film comprising a light-transmitting substrate and a functional layer, the functional layer comprising a nitrogen atom The functional layer has a thickness of 1 μm or more and 10 μm or less, In the functional layer, secondary ions in the depth direction of the functional layer were detected by time-of-flight secondary ion mass spectrometry. When the on intensity was measured, in the first region having a thickness of 0.3 μm including the surface of the functional layer, The functional layer is subjected to a measurement of the intensity of the secondary ions derived from the ultraviolet absorber in the depth direction of the functional layer. The ultraviolet absorber-derived second region having a thickness of 0.3 μm including a bisector dividing the layer into two equal parts the ratio of the intensities of the secondary ions in the first region is 1.1 or more and 4.0 or less, The intensity of secondary ions derived from the ultraviolet absorber on the functional layer having a thickness of 0.3 μm including the back surface A ratio of intensities of secondary ions originating from the ultraviolet absorber in a third region is 1.2 or more and 4.0 or less. That is, optical film.

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

[0021] [9] The functional layer comprises at least one of a fluorine atom-containing compound and a silicon atom-containing compound. The optical film according to the above [7] or [8],

[0022]

[10] The functional layer contains the fluorine atom-containing compound, and the time-of-flight secondary ion mass spectrometry The secondary ions derived from the fluorine atom-containing compound in the first region measured by an analytical method The intensity of the fluorine atom-containing compound in the second region and the third region is The optical film according to [9] above, wherein the intensity of each of the secondary ions is greater than the intensity of each of the secondary ions.

[0023]

[11] The functional layer contains the silicon atom-containing compound, and the time-of-flight secondary ion mass spectrometry Secondary ions derived from the silicon atom-containing compound in the first region measured by an analytical method The intensity of the silicon-containing compound in the second region and the third region is The optical film according to the above [9] or

[10] , wherein the intensity of each of the secondary ions is greater than the intensity of each of the secondary ions.

[0024]

[12] The optical film according to any one of [1] to

[11] above, and a polarizer provided on one side of the film.

[0025]

[13] A display device comprising: a display element; and the optical film according to any one of [1] to

[0011] above or the polarizing plate according to

[12] above, which is disposed on the viewer side of the display element. , image display device.

[0026]

[14] The image display device according to

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

[0027] According to one aspect of the present invention, it is possible to achieve a thin structure and to provide a first functional layer and a second functional layer. Optical film capable of improving adhesion, and polarizing plate including such optical film And an image display device can be provided.

[0028] According to another aspect of the present invention, it is possible to achieve a thin structure and have good surface hardness and good durability. Optical film having good scratch resistance and durability, polarizing light provided with such optical film A display panel and an image display device can be provided. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic diagram of the optical film according to the first embodiment. [Diagram 2] 2(A) to 2(C) are schematic diagrams showing the state of the folding test. [Diagram 3] FIG. 3 is a plan view of a sample used in a folding test. [Figure 4] 4(A) and 4(B) are diagrams that diagrammatically show the manufacturing process of the optical film according to the first embodiment. [Diagram 5] 5(A) and 5(B) are diagrams that diagrammatically show the manufacturing process of the optical film according to the first embodiment. [Figure 6] FIG. 6 is a schematic diagram of the polarizing plate according to the first embodiment. [Figure 7] FIG. 7 is a schematic configuration diagram of the image display device according to the first embodiment. [Figure 8] FIG. 8 is a schematic diagram of the optical film according to the second embodiment. [Figure 9] FIG. 9 is a partially enlarged view of the optical film of FIG. [Figure 10] FIG. 10 is a plan view of a sample for identifying the position at which the in-plane retardation is measured. [Figure 11] 11(A) and 11(B) are diagrams illustrating the manufacturing process of the optical film according to the second embodiment. [Figure 12] 12(A) and 12(B) are diagrams illustrating the manufacturing process of the optical film according to the second embodiment. [Figure 13] FIG. 13 is a schematic diagram of a polarizing plate according to the second embodiment. [Figure 14] FIG. 14 is a schematic configuration diagram of an image display device according to the second embodiment. [Figure 15] FIG. 15 is a depth profile of the hard coat layer in the optical film according to Example B1 measured by time-of-flight secondary ion mass spectrometry. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] [First embodiment] The optical film and image display device according to the first embodiment of the present invention will be described below with reference to the drawings. In this specification, the terms "film", "sheet", etc. are used as designations. Thus, for example, The term "film" is used to include members also called sheets. 2A to 2C are schematic diagrams of the optical film, showing the state of a folding test. FIG. 3 is a plan view of a sample used in a folding test. 4 and 5 are diagrams that diagrammatically show the manufacturing process of the optical film according to this embodiment.

[0031] <<<<Optical films>>>> The optical film 10 shown in FIG. 1 includes a light-transmitting substrate 11, a first functional layer 12, and a second functional layer 13. The optical film 10 includes a first functional layer 12, a second functional layer 13, and a second functional layer 14 in this order. The present invention further includes a mixed layer 14 formed between the layers. In optical films, it is a layer that is intended to perform some function. Examples of the functional layer include a base layer for improving adhesion to a light-transmitting substrate, a hard coat layer, and a a coating layer, a spectral transmittance adjusting layer, an antiglare layer, an invisible layer, a refractive index adjusting layer, an antifouling layer, or any of these The "functional layer" in this embodiment has a single layer structure.

[0032] The thickness (total thickness) of the optical film 10 is 5 μm or more and 80 μm or less. It is preferable that the optical film 10 has a thickness of 5 μm or more to obtain a desired pencil hardness. 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 manner, the optical film 10 can be used to display an image. When the image display device is assembled, the overall thickness of the image display device can be reduced. The lower limit of the thickness of the optical film 10 is determined based on the mechanical strength of the optical film 10. From the viewpoint of ensuring the above, the thickness is preferably 8 μm or more, 10 μm or more, or 15 μm or more. From the viewpoint of further reducing the thickness of the optical film 10, the thickness is set to 50 μm or less, 40 μm or less, or A thickness of 30 μm or less is preferable.

[0033] In addition, in order to impart flexibility to the optical film 10 as described later, a light transmitting Although it depends on the resin system of the plastic substrate 11, the thickness of the optical film 10 is preferably 73 μm or less, and more preferably 63 μm or less. In particular, even if the side interval φ in the folding test described later is small, the folding In order to avoid being biased toward the folding direction, the thickness of the optical film 10 is set to 48 μm or less, and further set to 43 μm or less. In addition, in order to obtain flexibility while also ensuring mechanical strength, The thickness of the optical film 10 is preferably 21 μm or more, and more preferably 28 μm or more.

[0034] The total 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. If the total thickness is 1 μm or more, strong adhesion is achieved between these layers. Furthermore, if the total thickness is 10 μm or less, the thickness can be reduced. Here, in the optical film of the present invention, most of the thickness is occupied by the light-transmitting substrate. Therefore, depending on the final design of the image display device, it may be necessary to make the light-transmitting substrate thin. In such a case, unless the thickness of the mixed layer 14 is thinned, the above-mentioned optical The overall thickness of the optical film is 80 μm or less, and 50 μm or less for particularly good flexibility. Conventionally, a single functional layer of, for example, 10 μm thick was sufficient. In order to secure this, a large amount of functional components must be added to the functional layer. As a result, the components in the functional layer that can provide adhesion to the light-transmitting substrate are insufficient, and good adhesion is not obtained. Therefore, it is necessary to obtain an amount of a component that provides adhesion to a light-transmitting substrate. In order to achieve this, it is necessary to reduce the concentration of the functional component in the functional layer. With the reduced density, sufficient adhesion was obtained as with the 10 μm single functional layer described above. In order to ensure the functionality, the thickness of the functional layer must be increased. As described above, the component that provides adhesion to the light-transmitting substrate is insufficient, and therefore the optical The film also lacked 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. The upper limit of the total film thickness is preferably 2.5 μm or more. From the viewpoint of miniaturization, the thickness 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 FIG. 1 is the surface 13A of the second functional layer 13. However, when the third functional layer is formed on the surface of the second functional layer, the optical filter The surface of the functional layer is the surface of the third functional layer. In this case, the surface on the light-transmitting substrate side means the surface on the opposite side.

[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 %, the photodegradation of the polarizer can be suppressed. From the viewpoint of further suppressing the photodegradation of the polarizer, the It is more 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 optical film 10 has a spectral transmittance of 20 at a wavelength of 410 nm. % or less, the light deterioration of a display element, for example, an OLED element, can be further suppressed. The spectral transmittance at 10 nm is set to 18% or less, and 1 It is more preferable that it is 5% or less, or 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 optical film 10 has a spectral transmittance of 75 at a wavelength of 440 nm. % or more, the decrease in visibility due to coloring can be suppressed. The transmittance is set to 78% or more, 80% or more, or It is more preferable that the ratio is 85% or more.

[0040] The above spectral transmittance was measured by cutting an optical film into a size of 50 mm x 50 mm. A spectrophotometer capable of measuring in 0.5 nm increments (product name: UV-2450, Shimadzu Corporation) Light transmittance of optical film in (light source: tungsten lamp and deuterium lamp) The substrate was placed on the light source side, and the measurement conditions were as follows: wavelength 380 nm, 41 Transmittance of at least 5 points within 1 nm at 0 nm and 440 nm The wavelength is 380 nm. The spectral transmittance at 410 nm and 440 nm was measured three times. If there are any undulations in the spectrum of the spectral transmittance, Smoothing treatment may be performed with a filter of 5.0 nm. If you are unable to cut it out, we can use the above dimensions as long as it is at least 15mm x 40mm. It doesn't have to be that way. (Measurement conditions) ·Wavelength range: 300nm~780nm Scan speed: Fast Slit width: 2.0 Sampling interval: Auto (0.5 nm interval) ·Lighting:C Light source: D2 and WI ·Field of view: 2° Light source switching wavelength: 360nm S / R Switching: Standard Detector: PM Autozero: Performed at 550 nm after baseline scan ·Temperature: 23±5℃ Relative humidity: 30% to 70%

[0041] The spectral transmittance of the optical film 10 is extremely low, less than 1%, up to a wavelength of 380 nm. It may gradually increase from 410 nm and suddenly increase around the wavelength of 440 nm. Specifically, for example, the optical film 10 has a wavelength range of 380 nm to 440 nm. The light transmittance may vary along a sigmoid curve.

[0042] The optical film 10 preferably has a blue light blocking rate of 20% or more. If the blue light blocking rate is 20% or more, the problems caused by blue light described below will be sufficiently eliminated. The above blue light blocking rate can be calculated by, for example, The optical film cut into pieces was then measured using a spectrophotometer ( Product name: UV-2450, manufactured by Shimadzu Corporation, light source: tungsten lamp and heavy The optical film was placed in a hydrogen lamp with the light-transmitting substrate side facing the light source. At least 5 points of transmission within 1 nm of each wavelength from 300 nm to 780 nm The blue light blocking rate (%) is A, and the wavelength is 380 nm to 500 nm. The average transmittance (%) at wavelengths of 500 nm to 650 nm is taken as B, and the average transmittance ( %) is C, and the blue cut rate is calculated using the following formula (1). The shielding rate is the arithmetic average of the values ​​obtained by measuring three times. The above-mentioned conditions for measuring the spectral transmittance at wavelengths of 380 nm, 410 nm, and 440 nm are is the same as: 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 yellowish color of the optical film 10 can be suppressed. It can also be used in applications where transparency is required. The Yellow Index (YI) is 50mm x The optical film was cut into a size of 50 mm and stored at a temperature of 23±5°C and a relative humidity of 30% or less. A spectrophotometer (product name "UV-2450", Shimadzu Corporation) was used in an environment with a humidity level of 70% or less. (Light source: tungsten lamp and deuterium lamp) with the light-transmitting substrate side as the light source side From the transmittance of the optical film at wavelengths of 300 nm to 780 nm measured with the optical film placed as shown in the figure, 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 given in ASTM D1925:1962. The yellow index (YI) is calculated based on the following: The transmittance at wavelengths of 300 nm to 780 nm was measured three times and calculated three times. The arithmetic mean value of the values ​​obtained is used. The above-mentioned transparency is displayed on a personal computer (PC) connected to the UV-2450. By reading the measured data of the pass rate and checking the "YI" item in the calculation items, The measurement conditions for the transmittance at wavelengths of 300 nm to 780 nm are as follows: The measurement conditions for the spectral transmittance at 410 nm, 410 nm, and 440 nm are the same as those for YI. The lower limit is preferably low from the viewpoint of ensuring high transparency, but it is also preferable to have a low UV absorption performance. Considering the contribution of the stimuli, it is more preferable that the number is 1 or more, 2 or more, or 3 or more. However, if YI is too large, the color may turn yellowish. The upper limit is 10 or less, 7 or less, or It is more preferable that it is 6 or less.

[0044] The optical film 10 preferably has a total light transmittance of 80% or more. If the total light transmittance of the optical element 10 is 80% or more, sufficient optical performance can be obtained. From the viewpoint of obtaining better optical performance, the total light transmittance of the film 10 is set to 88% or more, 89% or more. or more preferably 90% or more.

[0045] The above total light transmittance is measured under conditions of temperature 23±5℃ and relative humidity 30% to 70%. In accordance with JIS K7361-1:1997, a haze meter (product name: HM-15 0" manufactured by Murakami Color Research Laboratory Co., Ltd.) was used to print the optical film on a 50mm x 50mm After cutting to size, the light-transmitting substrate is left free of curls, wrinkles, fingerprints, dust, etc. The optical film was placed on the light source side and measurements were taken three times. In this specification, "measured three times" means measuring the same place three times. This means that the measurement is not done at one place, but at three different places. 10 has a flat surface when visually observed, and the layers laminated thereon, such as the first functional layer 12, are also flat. The thickness variation is within the range of ±10% of the average thickness, preferably within the range of ±5%. Therefore, the total light transmittance of the cut optical film was measured at three different points. This is thought to give an approximate average value of the total light transmittance of the entire surface of the optical film. If the optical film cannot be cut to the above size, for example, HM-150 The inlet opening for measurement is 20 mm in diameter, so the diameter must be 21 mm or more. A sample is required. For this reason, the optical film is applied to a size of 22 mm x 22 mm or more. If the size of the optical film is small, cut it out as needed. The measurement points are set to three by shifting the measurement point slightly around the optical film or by changing the angle. In the case of 10, the variation in the total light transmittance obtained is large when the measurement object is 1m x 3000m long. Whether it's a 100cm square or 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 the film 10 is 1% or less, the optical film 10 is used in a mobile device. In this case, the whitening of the screen can be suppressed. From the viewpoint of the above, it is 0.5% or less, 0.4% or less, 0.3% or less, or 0.2% or less. It is more preferable that

[0047] The above haze values ​​are measured under conditions of temperature 23±5℃ and relative humidity 30% to 70%. A JI was measured using a color meter (product name "HM-150", manufactured by Murakami Color Research Laboratory Co., Ltd.). It can be measured by a method conforming to S K7136:2000. The noise value is measured in the same manner as in the measurement of the 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 was carried out on the surface of an optical film cut to a size of 50 mm x 100 mm. Pencil hardness tester (product name: Pencil scratch coating hardness tester (electric type)), Toyo Seiki Co., Ltd. The test was performed using a test piece manufactured by KIKAI Co., Ltd., in an environment with a temperature of 23±5°C and a relative humidity of 30% to 70%. A 300g load was applied to a pencil (product name "Uni", manufactured by Mitsubishi Pencil Co., Ltd.) and the pencil was moved 3mm / The pencil hardness test is performed by moving the pencil at a speed of 100 / s. The hardness is the highest hardness that does not scratch the surface of the optical film 10. When determining the hardness, multiple pencils with different hardness are used, and each pencil is tested five times. If the surface of the optical film 10 is not scratched four or more times out of five times, It is judged that the surface of the optical film 10 was not scratched by the pencil of hardness. The surface of the optical film 10 subjected to the pencil hardness test was observed under a fluorescent lamp. This refers to.

[0049] Optical film 10 was placed in an environment with a temperature of 23±5°C and a relative humidity of 30% to 70%. In contrast, the distance φ between the opposing sides of the optical film 10 is 6 mm, and the second functional layer 13 is The folding test was performed 100,000 times, 200,000 times, and 500,000 times. Even if the test is repeated 1 million times, the optical film 10 does not crack or break. It is preferable that no such phenomenon occurs. The optical film 10 is repeatedly subjected to a folding test 100,000 times. If the optical film 10 is cracked or broken when folded, the optical film 10 may be damaged. The more times the folding is performed, the more likely the product is to break or be torn. Therefore, the number of folding times is 200,000, 300,000, 500,000 or 1 million. The optical film does not crack or break after the folding test, even if it is folded 100,000 times. The optical film is not subject to any cracks or breaks after the folding test. In addition, the number of times the folding test was performed was at least 100,000. For example, the optical film can be made into a foldable smart If we were to incorporate it into a phone, the frequency of folding (opening and closing) would be very high. For this reason, the number of times the folding test is performed is, for example, 10,000 or 50,000 times. However, there is a possibility that it may not be possible to carry out a practical evaluation. Assuming that someone who uses a smartphone all the time uses it five times just during their morning commute on the train or bus. It is expected that you will open and close your smartphone about 10 times a day. It is assumed that the smartphone will be opened and closed 0 times. Assuming that the product is opened and closed 30 times, the folding test with 10,000 folding times is 30 times x 3 65 days = 10,950 times, so the test assumes one year of use. Even if the results of a folding test of 10,000 times are good, the optical film may not function properly after one year. Therefore, the folding test was performed using a folding film. Evaluations conducted 10,000 times only confirm a level at which the product cannot be used. Even if it is usable but insufficient, it will be considered as good and cannot be evaluated. In order to evaluate whether the product is at a practical level, the number of folds in the above folding test should be small. It is necessary to evaluate at least 100,000 times. The distance φ between the opposing sides of the optical fiber 10 is 6 mm, and the second functional layer 13 is arranged on the outside. Even if the film 10 is folded 100,000 times, the optical film 10 does not crack or break. It is more preferable that this does not occur.

[0050] In the folding test, the distance φ between the opposing sides of the optical film 10 was 6 mm. However, from the viewpoint of making the image display device thinner, The interval φ is further narrowed, specifically to 4 mm, by folding 180° 100,000 times. It is more preferable that no cracks or breaks occur even when a folding test is performed. Even if the number of folding times is the same, the narrower the interval φ, the more likely it is to crack or It is difficult to prevent breakage, so after the folding test with the above interval φ of 4 mm The absence of cracks or breaks in the optical film is due to the folding interval φ of 6 mm. The optical film is not subject to any cracking or breakage after the bending test. There is a difference.

[0051] When carrying out the folding test, first, a part of the optical film 10 before the folding test is A sample S1 of a given size (e.g., a rectangular shape of 125 mm x 50 mm) is cut out from the sample. (See Figure 2(A)). However, it is not possible to cut out a sample to a size of 125 mm x 50 mm. In this case, the size is sufficient as long as it is large enough to enable the various evaluations described below to be performed after the folding test. For example, A sample may be cut into a rectangular shape measuring 80mm x 25mm. Before the folding test After cutting out a sample S1 from the optical film 10, a folding test was performed on the sample S1. Conduct an experiment.

[0052] The folding test is carried out as follows. As shown in Figure 2(A), In the measurement, first, a side portion S1a of the sample S1 and a side portion S1b opposite to the side portion S1a are A folding durability tester arranged in parallel (for example, the product name "U-shaped stretch tester DLDMLH- FS, manufactured by Yuasa System Co., Ltd., compliant with IEC62715-6-1) fixed part 15 The sample S1 is fixed to the fixing parts 15 and 16 in the longitudinal direction of the sample S1. This is done by holding a portion of the sample S1 about 10 mm on one side. If the size of the sample S1 is smaller than the above size, the portion of the sample S1 required for this fixation If the distance is up to about 20 mm, it can be measured by attaching it to the fixing parts 15 and 16 with tape. (That is, the minimum sample size is 60 mm × 25 mm.) Also, as shown in Figure 2(A), As shown in the figure, the fixing part 15 is slidable in the horizontal direction. Unlike conventional methods such as wrapping a sample around a rod, this method does not apply tension or friction to the sample. This is preferable because it makes it possible to evaluate the durability against bending load without causing any damage to the specimen.

[0053] Next, as shown in FIG. 2(B), in a state where the fixing portion 16 is fixed, the fixing portion 15 and the fixing portion 1 The fixing portion 15 moves so that the center portion S1c of the sample S1 approaches the center portion S1c of the sample S1. Then, as shown in FIG. 2(C), the sample S1 is deformed so that the sample S1 is fixed to the fixing portions 15 and 16. The fixed portion 1 is moved to a position where the distance φ between the two fixed opposing side portions S1a and S1b becomes 6 mm. After moving the fixing portion 5, the fixing portion 15 is moved in the opposite direction to remove the deformation of the sample S1.

[0054] As shown in FIG. 2(A) to (C), the fixing part 15 is moved to center the sample S1. The sample S1 can be folded 180° at the bent portion S1c. 15, 16, and perform the folding test under the following conditions and fix it. By controlling the distance between the fixing part 15 and the fixing part 16 at the closest position to 6 mm, the sample S The distance φ between the two opposing sides S1a and S1b of the bent portion S1 can be set to 6 mm. 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 ( 6mm), the result of the folding test of sample S1 is It can be considered that there is no effect due to the difference in thickness of sample S1. (Folding conditions) Reciprocating speed: 80 rpm (revolutions per minute) Test stroke: 60mm Bending angle: 180°

[0055] When the above folding test was performed on sample S1, cracks were observed in sample S1 after the folding test. Even if no breakage occurs, creases may form at the bend and microcracks may occur. This can lead to poor appearance, specifically white turbidity and delamination caused by microcracks ( One of the causes of the clouding phenomenon is the This is thought to be due to a change in the crystalline state of the organic compound that is the material of the layer. When this occurs, moisture may accumulate in the delamination area due to changes in temperature and humidity, or the delamination area may Air may get in, which may cause the display to become cloudy. Instead, there is an increase in folding, curved, and diverse three-dimensional designs. The suppression of creases and microcracks at the bent portions is extremely important for use as an image display device. For this reason, it is important that the optical film 10 has flexibility. In the present embodiment, the term "flexibility" refers to the degree of flexibility after the folding test. Not only was there no cracking or breaking, but also no creases or microcracks were observed. Therefore, in this embodiment, "flexibility" means the above folding. Flexibility, which is the only requirement that no cracks or breaks occur after folding test are different.

[0056] The above observation of creases is to be done visually, but the creases should be observed under white lighting. In a room (800 lux to 2000 lux), the bent part is evenly illuminated by transmitted and reflected light. Observe the inside and outside of the bent portion when folded. The above folding crease observations shall be performed at a temperature of 23±5°C and a relative humidity of 30%. This should be done in an environment with a humidity level of 70% or lower.

[0057] The above microcracks are observed using a digital microscope. As a digital microscope, for example, the VH manufactured by Keyence Corporation is used. X-5000. Microcrack is used as lighting for digital microscopes. The ring illumination should be selected and the observation should be performed in dark field and reflected light. First, the sample after the folding test was slowly unfolded and placed on the stage of a microscope. If the sample is strongly folded, fix it in place so that the area to be observed is as small as possible. However, do not touch the area to be observed (the bent part) near the center of the sample with your hands. The part that will be inside when folded and the part that will be outside when folded will be the same. The above microcracks are observed at a temperature of 23±5°C. The test shall be performed in an environment with a relative humidity of 30% or higher and 70% or lower.

[0058] In observing the creases and the microcracks, the positions to be observed are easily identified. The sample before the folding test was placed on the fixed part of the durability tester so that it could be grasped, and folded once. When the bending portion S1 is folded, as shown in FIG. Mark the ends S1d1 in the direction of the bend with a mark M1 using an oil-based pen or similar. In addition, if no creases are observed in the sample after the folding test, To prevent the observation position from becoming unclear, the sample was removed from the durability tester after the folding test. In this state, a line M2 (in FIG. 3) connecting the marks M1 on both ends S1d1 of the bent portion S1d is You can also draw a dotted line (a line that indicates the crease) with an oil-based pen. The area formed by the marks M1 on both ends S1d1 of the portion S1d and the line M2 connecting these marks M1 The entire bent portion S1d is visually observed. The center of the cross-scope field of view (the area surrounded by the two-dot chain line in FIG. 3) is the bent portion S1d. Adjust the microscope position so that it is in the center. Be careful not to write in the sample area required for actual measurement.

[0059] In addition, when the above folding test was performed on sample S1, the light-transmitting substrate and the first functional layer were Therefore, the adhesion of the optical film to the bending test may be deteriorated. In the portion, the vicinity of the interface between the light-transmitting substrate 11 and the first functional layer 12 is subjected to digital microscopy. When observed under a microscope, peeling or the like was observed near the interface between the light-transmitting substrate 11 and the first functional layer 12. It is preferable that the digital microscope is not used. One example is the company's VHX-5000.

[0060] When other films such as polarizing plates are attached to the optical film via a pressure-sensitive adhesive layer or bonding layer After peeling off the adhesive layer and other films, the spectral transmittance, YI, total light The transmittance, haze value, pencil hardness shall be measured, and a folding test shall be carried out. The peeling of the adhesive layer can be carried out, for example, as follows. The laminate with other films attached via the adhesive layer is heated with a dryer to separate the optical film and the other films. Insert the tip of the cutter into the area that appears to be the interface of the film and slowly peel it off. By repeating this heating and peeling process, the adhesive layer, the bonding layer, and other films are peeled off. Even if such a peeling process is performed, it is difficult to measure the spectral transmittance, etc. There is no significant impact.

[0061] As described above, the spectral transmittance, YI, total light transmittance, haze, and the like of the optical film 10 are When measuring the value and pencil hardness, it is necessary to cut the optical film 10 into the above sizes. However, when the size of the optical film 10 is large (for example, when it is in a roll shape), After cutting out the sample from the desired position to A5 size (148mm x 210mm), the size of each measurement item was For example, when the optical film 10 is in a roll shape, In this case, a predetermined length of the optical film 10 is unwound from the roll, and the roll is rotated in the longitudinal direction. The effective area near the center where the quality is stable is not the non-effective area including both ends extending along the The optical film 10 is cut out from the region. When measuring the optical transmittance, haze value, and pencil hardness, the above-mentioned device is used. The folding test of the film 10 is carried out using the above-mentioned device, but it can be carried out using other devices as well. Measurements and folding tests may be performed using equipment of similar quality, such as successor models.

[0062] The use of the optical film 10 is not particularly limited, but examples of the use of the optical film 10 include: For example, smartphones, tablet devices, personal computers (PCs), wearables Image display devices such as mobile terminals, digital signage, televisions, and car navigation systems The optical film 10 is also suitable for use in vehicles. The shape of the material is suitable for applications that require flexibility, such as foldable and rollable. is also preferred.

[0063] The optical film 10 may be cut to a desired size, or may be in a roll. When the optical film 10 is cut to a desired size, the size of the optical film is not particularly limited and is appropriately determined depending on the size of the display surface of the image display device. The size of the optical film 10 is, for example, 2.8 inches or more and 500 inches or less. In this specification, "inch" means that when the optical film has a rectangular shape, It means the length of the diagonal, in the case of a circle, it means the diameter, in the case of an ellipse, The average value of the sum of the minor axis and the major axis is used here. In this case, the aspect ratio of the optical film when calculating the above inches is the display screen of the image display device. There is no particular limitation as long as there is no problem. For example, vertical:horizontal=1:1, 4:3, 16:10, 16 However, especially for in-vehicle applications and digital signage, The aspect ratio of the optical film 10 is not limited to this. When the optical film 10 is in a roll form, a predetermined length is cut from the roll of the optical film 10. The roll is then rolled out in a non-useful area including both ends extending along the longitudinal direction of the roll, but not in a non-useful area including both ends of the roll. The desired size is cut out 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 having light-transmitting properties. A small amount of cellulose-based resins, cycloolefin polymer-based resins, and (meth)acrylic resins When outdoors, sunglasses are worn to prevent the image display device from being damaged. If you are viewing a displayed image and your sunglasses are polarized, When a displayed image is viewed through a glass, rainbow irregularities may occur, reducing visibility. This is believed to be due to the high in-plane phase difference (in-plane retardation, Re) of the light-transmitting substrate. Therefore, even if you currently view a displayed image through polarized sunglasses, There is a demand for suppressing the decrease in visibility. If the substrate contains an oil or (meth)acrylic substrate, the in-plane retardation is 10 nm or less. The light-transmitting substrate containing the cycloolefin polymer resin includes a substrate in which the retardation is not adjusted. There are also substrates with retardation adjusted to, for example, λ / 4. The in-plane retardation of the substrate is 10 nm or less. The phase difference is 150 nm or less. Therefore, acetyl cellulose resin, cycloolefin The light-transmitting substrate 11 containing a methacrylic resin or a (meth)acrylic resin has a surface The low internal phase difference suppresses the decrease in visibility when viewing the displayed image through polarized sunglasses. The above in-plane retardation is a value measured at a wavelength of 589 nm.

[0065] Examples of acetyl cellulose resins include triacetyl cellulose resins and diacetyl cellulose resins. Triacetyl cellulose resins are suitable for use in the visible light range of 380°C. This resin is capable of achieving an average light transmittance of 50% or more at wavelengths up to 780 nm. The average light transmittance of the acetyl cellulose resin is preferably 70% or more, and more preferably 85% or more. I wish.

[0066] In addition to pure triacetyl cellulose, triacetyl cellulose resins include Cellulose such as cellulose acetate propionate and cellulose acetate butyrate As the fatty acid that forms an ester with the acetic acid, a component other than acetic acid may be used in combination. In addition, these triacetyl celluloses may be optionally mixed with other compounds such as diacetyl cellulose. In addition, a cellulose lower fatty acid ester such as the above may be added.

[0067] Cycloolefin polymer resins include norbornene resins, monocyclic olefin resins, Polyolefin resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and their hydrogenated derivatives Among these, norbornene-based resins are preferred because of their transparency and moldability. Since the properties are good, it can be preferably used.

[0068] The norbornene-based resin is a ring-opening polymer of a monomer having a norbornene structure or The present invention relates to a ring-opening copolymer of a monomer having a norbornene structure with another monomer, or a copolymer of these monomers. norbornene structure-containing monomer addition polymer or norbornene structure-containing monomer addition polymer Examples of the copolymer include an addition copolymer of the monomer with another monomer, and hydrogenated products thereof. can.

[0069] Commercially available cycloolefin polymer resins include, for example, Zeon Corporation's Product name "ZEONEX (registered trademark)" and "ZEONOR (registered trademark)" (norbornene resin ), product name "SUMILITE (registered trademark) FS-1700" manufactured by Sumitomo Bakelite Co., Ltd., Arton (registered trademark) (modified norbornene resin) manufactured by JSR Corporation, Mitsui "Apel (registered trademark)" (cyclic olefin copolymer) manufactured by Chemical Industry Co., Ltd., Tico Topas (registered trademark) (cyclic olefin copolymer) manufactured by Hitachi Chemical Co., Ltd. "Optrets OZ-1000 Series" (alicyclic acrylic resin) manufactured by the Company A light-transmitting substrate can be obtained by forming a film from such a cycloolefin polymer resin. The film can be formed by any known method, including, but not limited to, a solvent casting method or a melt extrusion method. The known film-forming method can be used. Films are also commercially available and can be used as light-transmitting substrates. As an example of the polymer-based film, there is a product called "ESCINA (registered trademark)" manufactured by Sekisui Chemical Co., Ltd. "Zeonoa Film (registered trademark)" and "SCA40" are both products of Zeon Corporation. and Arton (registered trademark) Film manufactured by JSR Corporation.

[0070] Examples of the (meth)acrylic resin include poly(methyl(meth)acrylate), poly(meth)acrylate, p) Ethyl acrylate, methyl (meth)acrylate-butyl (meth)acrylate copolymer etc.

[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, it is possible to further reduce the thickness. 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. More preferably, the thickness is 10 μm or more, or 15 μm or more. The upper limit of the thickness is set to 50 μm or less, 45 μm or less, and 40 μm or less from the viewpoint of further thinning. It is more preferable that the thickness is at most 35 μm, or at most 30 μm.

[0072] The thickness of the light-transmitting substrate was measured by observing the cross section of the light-transmitting substrate using a scanning electron microscope (SEM). The thickness of the light-transmitting substrate was measured at 10 points on the cross-sectional image. The thickness can be determined by calculating the arithmetic mean value of the thickness. The imaging was performed at a magnification appropriate for the thickness of the light-transmitting substrate, and the interface line between the light-transmitting substrate and the functional layer was photographed. Specifically, for example, if the thickness of the light-transmitting substrate is 50 μm, For example, the thickness of the light-transmitting substrate is 1000 times larger for 100 μm, and 500 times larger for 100 μm. The variation in thickness of the light-transmitting substrate 11 is 15% or less. It is preferable that the difference is 0% or less, or 7% or less. When measuring the thickness of the light-transmitting substrate using a However, the magnification for taking a cross-sectional photograph of the light-transmitting substrate is 100 to 20,000 times. do.

[0073] When flexibility (e.g., foldability) is required for the optical film, If the material or functional layer is too thick, the light-transmitting base material or functional layer may crack at the bent portion when folded. In addition, creases or microcracks may occur in the light-transmitting substrate or functional layer at the bent portion. Cracks, creases and microcracks can cause poor appearance. Specifically, there is a risk of the occurrence of cloudiness or poor adhesion due to cracks. Therefore, when using optical films for flexible applications, the thickness of the light-transmitting substrate and the functional layer must be adjusted. Control of adhesion between layers (no adhesion due to chemical bonds affected by materials, no cracks) In particular, when the light-transmitting substrate 11 is made of acetyl cellulose, If resin, cycloolefin polymer resin, or (meth)acrylic resin is included Since the resistance to cracking varies depending on the thickness, it is important to control the thickness of the light-transmitting substrate. When the optical film 10 is folded (inward bending) so that the second functional layer 13 is on the inside, In the case of folding the optical film 10 so that the optical layer 13 is on the outside (outward bending), 11 has different preferred thicknesses.

[0074] (When optical film is used for inward bending) When the light-transmitting substrate 11 contains, for example, an acetyl cellulose-based resin, The thickness of the light-transmitting substrate 11 is preferably 15 μm or more and 60 μm or less. If the light-transmitting substrate is too thin, it may tear when folded. If the thickness of the material 11 is 15 μm or more, the light-transmitting base material 11 is prevented from tearing when folded. In addition, if the thickness of the light-transmitting substrate 11 is 60 μm or less, the light-transmitting substrate 11 can be prevented from being damaged at the bending portion when folded. This can suppress cracking of the light-transmitting substrate 11 at the bent portion, and also suppresses the clouding phenomenon at the bent portion. In this case, the upper limit of the thickness of the light-transmitting substrate 11 is set to be the thickness of the light-transmitting substrate 11 that is sufficient to prevent the above-mentioned cracks and cracks at the bent portion during further folding. From the viewpoint of suppressing the formation of opacity, the thickness is preferably 45 μm or less, more preferably 40 μm or less, even more preferably 35 μm or less, and particularly preferably 30 μm or less. It is preferable that the length is equal to or less than m.

[0075] When the light-transmitting substrate 11 contains, for example, a cycloolefin polymer resin, The thickness of the light-transmitting substrate 11 is preferably 5 μm or more and 50 μm or less. If the thickness of the material 11 is 5 μm or more, the handling property is good, and if it is 50 μm or less, If there is such a portion, cracking of the light-transmitting base material 11 at the bent portion during folding can be suppressed. In this case, the upper limit of the thickness of the light-transmitting substrate 11 is set to 100%. In order to prevent the above cracks and clouding at the bent parts when folded, the thickness should be 45 μm or less, 40 μm or less It is particularly preferably 30 μm or less, or 18 μm or less.

[0076] When the light-transmitting substrate 11 contains, for example, a (meth)acrylic resin, The thickness of the light-transmitting substrate 11 is preferably 15 μm or more and 50 μm or less. If the thickness is 15 μm or more, the handling property is good, and if it is 50 μm or less, In this way, cracking of the light-transmitting substrate 11 at the bent portion during folding can be suppressed. In this case, the upper limit of the thickness of the light-transmitting substrate 11 is set to 100 mm. From the viewpoint of suppressing the above-mentioned cracking and clouding of the bent portion at the time of bending, 45 μm or less, 40 μm or less, In particular, it is preferably 35 μm or less, or 30 μm or less.

[0077] When the thickness of each of the above-mentioned light-transmitting substrates is 35 μm or less, the light-transmitting substrate 11 is It is preferable to apply a protective film to the substrate since this improves processability.

[0078] (When optical film is used with outward bending) The light-transmitting substrate 11 is, for example, an acetyl cellulose resin or a cycloolefin polymer. In the case where the light-transmitting substrate 11 contains an acrylic resin or a (meth)acrylic resin, the thickness of the light-transmitting substrate 11 is 1 The thickness of the light-transmitting substrate 11 is preferably 10 μm or more and 50 μm or less. If it is more than this, it can absorb various shocks from the outside when used on the outside. If the thickness is 50 μm or less, cracking of the light-transmitting base material 11 at the bent portion during folding can be suppressed. In this case, the thickness of the light-transmitting substrate 11 is increased, and the occurrence of clouding at the bent portion can be suppressed. The limit is preferably 45 μm or less, or 30 μm or less.

[0079] The light-transmitting substrate 11 is preferably made of a material having a thickness of 100 nm or more and a thickness of 100 nm or more from the viewpoint of adhesion between the light-transmitting substrate 11 and the first functional layer 12. During the formation of the first functional layer 12, a component of the first functional layer 12 (for example, a polymerizable compound) is introduced. However, from the viewpoint of dimensional stability, it is preferable that the component of the first functional layer 12 is not included. It is preferable to use a non-permeable base material that does not become contaminated. Examples of the substrate include a substrate containing a cellulose-based resin or a (meth)acrylic resin, and a substrate containing no permeable material. Examples of the substrate include a substrate containing a cycloolefin polymer resin.

[0080] The light-transmitting substrate 11 is previously subjected to a surface treatment such as sputtering, corona discharge, ultraviolet irradiation, or electron beam irradiation. The plate may be subjected to etching treatments such as glazing, chemical conversion, oxidation, etc., or to undercoating treatments. By applying the coating in advance, the adhesion between the functional layer and the like formed on the light-transmitting substrate 11 is improved. In addition, before forming the first functional layer 12, etc., a solvent cleaning may be performed as necessary. The surface of the light-transmitting substrate 11 may be cleaned and purified by cleaning with a cleaning agent or ultrasonic cleaning.

[0081] <<<First functional layer>>> The first functional layer 12 serves as a base layer that improves the adhesion between the light-transmitting substrate 11 and the second functional layer. However, the first functional layer 12 may have other functions. When the optically transparent substrate 11 contains a cycloolefin polymer resin, Since the first functional layer 12 is difficult to adhere to the second functional layer 13, the first functional layer 12 is made to be in contact with the light-transmitting substrate 11 and the second functional layer 13. It is preferable that the first functional layer 12 is disposed between the light-transmitting substrate 11 and the light-transmitting substrate 13. In addition, the first functional layer 12 has optical transparency.

[0082] The thickness of the first functional layer 12 is preferably 0.1 μm or more and 5 μm or less. If the thickness of the first functional layer 12 is 0.1 μm or more, strong adhesion with the second functional layer 13 is ensured. In addition, if the thickness of the first functional layer 12 is 5 μm or less, a desired pencil hardness can be maintained. At the same time, the occurrence of cracks when the first functional layer 12 is bent or curved can be suppressed. 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. The thickness of the first functional layer 12 is preferably 0.5 μm or more. If the thickness of the first functional layer 12 is less than 100 μm, it is possible to obtain a hardness that can prevent scratches during the production process. The upper limit is 4.5 μm or less, 4 μm or less, or 3 μm or less from the viewpoint of obtaining a higher pencil hardness. It is preferable that:

[0083] In this embodiment, the "film thickness of the first functional layer" refers to the difference in contrast between the microscopic images. The interface line between the transparent substrate and the first functional layer can be recognized, and the interface line between the first functional layer and the mixed layer can also be recognized. The thickness of the first functional layer is the distance between the interface lines. Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) or Scanning Transmission Electron Microscope A cross section of the functional layer is photographed using a scanning electron microscope (STEM) or the like, and the first functional layer is The thickness is measured at 10 points and the arithmetic average of the thicknesses at those 10 points is calculated. This can be done.

[0084] The specific method for taking cross-sectional photographs is as follows. First, a section of 1 mm x 10 mm is The cut optical film was embedded in an embedding resin to create a block, and the optical film was extracted from this block. Using a general sectioning method, a uniform section with a thickness of 70 nm to 300 nm without holes was obtained. To prepare the sections, we used the Ultramicrotome EM UC7 (Leica Microtome). Then, the uniform slice without holes is used as the measurement sample. After that, a scanning transmission electron microscope (STEM) (product name: S-4800, A cross-sectional photograph of the measurement sample is taken using a microscope (manufactured by Hitachi High-Technologies Corporation). When taking cross-sectional images using the -4800, the detector was set to "TE" and the accelerating voltage to "30k The cross-section was observed at a magnification of 1000 V and an emission current of 10 μA. Adjust the contrast and brightness to 100-100 while observing whether each layer can be distinguished. The exposure time is appropriately adjusted to 10,000 times, preferably 10,000 times to 100,000 times depending on the film thickness of the first functional layer. In order to reduce measurement errors in the thickness, it is recommended to measure the thickness of the first functional layer at as low a magnification as possible. For example, if the thickness of the first functional layer is about 1 μm, the magnification is 20,000 times, and the thickness is about 0.5 μm. In this case, the magnification is preferably 30,000 to 100,000 times. Furthermore, the condenser lens 1 is set to "5.0". And set the WD to 8.9mm.

[0085] The indentation hardness of the first functional layer 12 is 50 MPa or more and 600 MPa or less. It is preferable that the indentation hardness of the first functional layer 12 is 50 MPa or more. In this way, the desired pencil hardness can be obtained and the deterioration of scratch resistance can be suppressed. If the indentation hardness of the functional layer 12 is 600 MPa or less, good flexibility can be obtained. In addition, the occurrence of cracks during chip cutting can be suppressed. "Indentation hardness" is determined from the load-displacement curve from loading to unloading the indenter. In addition, in a layer that is too soft, such as an adhesive layer, the indentation Even if an attempt is made to measure the index hardness of the first functional layer 12, it may be impossible to measure it. The lower limit of the axial hardness is set to 7 in order to obtain higher pencil hardness and good scratch resistance. 0MPa or more, 85MPa or more, 100MPa or more, or 150MPa or more In addition, the upper limit of the indentation hardness of the first functional layer 12 is preferably set to 100% by weight. In order to obtain the desired properties and to further suppress the occurrence of cracks during chip cutting, a 500MPa It is better to use 450MPa or less, 400MPa or less, or 350MPa or less. preferable.

[0086] Indentation hardness (H IT ) is a TI manufactured by HYSITRON. The measurement can be performed using the 950 TriboIndenter. Then, we cut out the optical film to a size of 1 mm x 10 mm and embedded it in resin to create a block. A measurement sample suitable for hardness measurement by the nanoindentation method is prepared. The samples were prepared using the ultramicrotome EM UC7 (Leica Microsys). Then, the surface of the measurement sample into which the indenter is to be pressed is The measurement sample is placed parallel to the stage surface using the HYSITRON. The stage is fixed to the TI950 TriboIndenter manufactured by the company. The maximum indentation load is 300μN on the flat part in the center of the cross section of the functional layer using the load control method. The Berkovich indenter was applied at a loading rate of 10 μN / s, and the load was changed from 0 μN to 300 μN in 30 seconds. The load is applied to the first functional layer up to 1 μN. In order to achieve this, the first functional layer is provided with at least 500 nm from each of the two ends of the first functional layer toward the center of the first functional layer. The Berkovich-type indenter is then pressed into the portion of the first functional layer that is 300 After holding the load at 300μN for 5 seconds, the load is removed from 300μN to 0μN in 30 seconds. The indentation depth h (nm) corresponding to the indentation load F (N) was continuously measured, and the load- Create a displacement curve. The indentation hardness H from the load-displacement curve is calculated. IT of, The maximum pressing load F is expressed as follows: max (N) is placed in contact with the first functional layer. Projected area A p (mm 2 ) and the value is calculated by dividing the value by the indentation. The hardness is the arithmetic average of the values ​​measured at 10 points. The measurement shall be performed in an environment with a temperature of 23±5°C and a relative humidity of 30% to 70%. do. H IT =F max / A p …(2) Here, A p is a value calculated by the following formula (3). A p =23.96(h max -0.75(h max -h r )) 2 …(3) In the above formula (3), h max is the maximum indentation depth, and h r is F max Unloading in The value at the intersection of the tangent to the curve with the horizontal axis (displacement) is the value.

[0087] The first functional layer 12 contains a resin and an ultraviolet absorbing agent. It is sufficient that the first functional layer 12 or the second functional layer 13 contains the The first functional layer 12 may contain, in addition to the resin and the ultraviolet absorbing agent, It may contain a polymerization initiator or its residue.

[0088] <<Resin>> The resin contained in the first functional layer 12 includes a polymer (cured product) of a polymerizable compound. Resins include polymerized compounds, solvent-drying resins, and thermosetting compounds. It's fine.

[0089] (polymerizable compound) The polymerizable compound has at least one polymerizable functional group. The term "polymerizable functional group" refers to a functional group capable of undergoing a polymerization reaction. Examples of the polymerizable functional group include Examples of ethylenically unsaturated groups include an ethylenically unsaturated group such as a (meth)acryloyl group, a vinyl group, or an allyl group. In this specification, the term "(meth)acryloyl group" refers to an "acryloyl group" or "meth The term "acryloyl group" also refers to the ionizing radiation irradiated when polymerizing a polymerizable compound. Radiation includes visible light, ultraviolet light, X-rays, electron beams, alpha rays, beta rays, and gamma rays. .

[0090] Examples of the polymerizable compound having one ethylenically unsaturated group include ethyl (meth)acrylate. acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinyl Examples of the polymerizable compound having two or more ethylenically unsaturated groups include pyrrolidone and the like. Examples of the acrylates include polymethylolpropane tri(meth)acrylate and hexanediol. (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene Ethylene glycol di(meth)acrylate, Pentaerythritol tri(meth)acrylate , dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di( Polyfunctional compounds such as meth)acrylate, neopentyl glycol di(meth)acrylate, etc. or a reaction product of the above polyfunctional compound with a (meth)acrylate or the like (e.g., a polyhydric alcohol) Poly(meth)acrylate ester of ethylenediaminetetraacetate.

[0091] The polymerizable compound may be a polymerizable monomer, a polymerizable oligomer, and / or a polymerizable polymer. The copolymer can be appropriately prepared and used.

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

[0093] The thermoplastic resin is not particularly limited, and examples thereof include styrene-based resins, (meth)acrylic resins, and the like. vinyl acetate resin, vinyl ether resin, halogen-containing resin, alicyclic olefin resin, polycarbonate resin, polyester resin, polyamide resin, cellulosic resin Examples of the material include silicone derivatives, silicone resins, and silicone rubbers.

[0094] The thermoplastic resin is amorphous and can be easily dissolved in an organic solvent (particularly, a mixture of multiple polymers and polymerizable compounds). In particular, it is preferable that the composition is soluble in a common solvent capable of dissolving the above-mentioned compounds. From the viewpoint of the above, styrene resins, (meth)acrylic resins, alicyclic olefin resins, polyethylene resins, etc. Preferred are steric resins, cellulose derivatives (such as cellulose esters), and the like.

[0095] (thermosetting compound) The thermosetting compound is not particularly limited, and examples thereof include phenol resin, urea resin, and diamine resin. phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane ethane resin, epoxy resin, amino alkyd resin, melamine-urea co-condensation resin, silicon resin, polysiloxane resin, etc.

[0096] <Ultraviolet absorbing agent> The ultraviolet absorber is a material that absorbs at least ultraviolet light (wavelength 10 nm to 400 nm). As long as the ultraviolet absorbent absorbs ultraviolet light, it has a maximum absorption wavelength in the visible light region. In the case of an ultraviolet absorbing agent, the wavelength range is 360 nm or more and 430 nm or less. The maximum absorbance of the ultraviolet absorbing agent is preferably 0.5 or more. Benzotriazole compounds, indole compounds, benzophenone compounds, triazines Among these, from the viewpoint of suppressing the decrease in visibility due to coloring, Benzotriazole compounds and indole compounds are preferred.

[0097] Whether or not the first functional layer 12 contains an ultraviolet absorbing agent is determined by first collecting a piece of the first functional layer 12. The pieces were then measured by infrared spectroscopy (IR) and the resulting infrared absorption spectrum was This can be checked by comparing it with commercially available UV absorbers. The resin constituting the functional layer 12 may contain the polymer as a copolymer.

[0098] The benzotriazole-based compound is, for example, a sesame oil represented by the following general formula (A): Benzotriazole monomer, 2-[2-hydroxy-3,5-bis(α,α-dimethyl [1-(4-benzyl)phenyl]-2H-benzotriazole (product name: Tinuvin 234) , manufactured by BASF), 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl p-cresol (product name "Tinuvin 326", manufactured by BASF) Among these, those with a large spectral slope and the ability to more selectively absorb ultraviolet light are Therefore, the sesamol-type benzotriazole monomer represented by the following general formula (A) can be used. Body is preferred. [ka] In the formula, R 1 R represents a hydrogen atom or a methyl group. 2 is a linear or branched chain with 1 to 6 carbon atoms A chain alkylene group or a straight or branched oxyalkylene group having 1 to 6 carbon atoms. Represents a group.

[0099] The sesamol-type benzotriazole monomer represented by the above general formula (A) is a first functional layer The monomer unit is contained in the resin constituting 12. Also, the monomer unit represented by the above general formula (A) is Sesamol-type benzotriazole monomers have a nitrogen atom at the 2nd position of the benzotriazole ring. It is a derivative of a compound that combines sesamol and the benzene moiety of the benzotriazole ring. This monomer has a molecular structure in which a polymerizable double bond is introduced at the 2-position. max The wavelength is 365 nm or more, and covers a wide range of wavelengths from 300 nm to 400 nm. It has an ultraviolet absorption spectrum ranging from 100 nm to 400 nm, and has the ability to absorb ultraviolet rays up to the long wavelength region around 400 nm. do.

[0100] The sesamol-type benzotriazole monomer is not particularly limited, but specific examples include The substance name is 2-[2-(6-hydroxybenzo[1,3]dioxol-5-yl )-2H-benzotriazol-5-yl]ethyl methacrylate, 2-[2-(6-Hydroxyethyl hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole-5- 3-[2-(6-hydroxybenzo[1,3]dioxole -5-yl)-2H-benzotriazol-5-yl]propyl methacrylate, 3-[ 2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole 5-phenyl-5-yl]propyl acrylate, 4-[2-(6-hydroxybenzo[1,3 ]dioxol-5-yl)-2H-benzotriazol-5-yl]butyl methacrylate 4-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H- Benzotriazol-5-yl]butyl acrylate, 2-[2-(6-hydroxybenzo Zo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yloxy] Ethyl methacrylate, 2-[2-(6-hydroxybenzo[1,3]dioxole-5 -yl)-2H-benzotriazol-5-yloxy]ethyl acrylate, 2-[3 -{2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzothiazolinone 2-[3-{2-( 6-Hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole -5-yl}propanoyloxy]ethyl acrylate, 4-[3-{2-(6-hydroxy (benzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl propanoyloxy]butyl methacrylate, 4-[3-{2-(6-hydroxybenzo [1,3]dioxol-5-yl)-2H-benzotriazol-5-yl}propano 2-[3-{2-(6-hydroxybenzo[1,3]yloxy]butyl acrylate Dioxol-5-yl)-2H-benzotriazol-5-yl}propanoyloxy ]ethyl methacrylate, 2-[3-{2-(6-hydroxybenzo[1,3]dioxo (2H-benzotriazol-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]dioxole-5 -yl)-2H-benzotriazole-5-carboxylate, 4-(methacryloyl) 2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-butyl Benzotriazole-5-carboxylate, 4-(acryloyloxy)butyl 2-( 6-Hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole In addition, these sesamol-type benzotriesters can be used as benzotriesters. The azole monomer may be used alone or in combination of two or more kinds.

[0101] (Indole compounds) Examples of the indole-based compound include compounds represented by the following general formula (B): In the case of a compound represented by the following general formula (B), the wavelength is 380 nm or more and 400 nm or less. It can absorb light in the wavelength range. [ka] In formula (B), R 3 represents a linear or branched alkyl group or an aralkyl group, R 4 -CN or -COOR 5 where R 5 may have a substituent Alkyl or aralkyl group (where R 3 is a methyl group, ethyl is excluded. )

[0102] R 3 The carbon number of R can be 1 to 12. 3 A concrete example of this is butyl group, ethyl group, (iso)butyl group, t-butyl group, hexyl group, octyl group, 2-ethyl R includes an ethylhexyl group, a dodecyl group, and a benzyl group. 5 A concrete example of this is If the above R 3 The groups exemplified in 1 and β-cyanoethyl group, β-chloroethyl group, ethoxypropyl group, Examples of the alkyl groups include alkyl groups, hydroxyalkyl groups, and alkoxyalkyl groups. 3 GaMe When R is a ethyl group, 5 is not an ethyl group.

[0103] As an indole-based compound, BONASORB U manufactured by Orient Chemical Industry Co., Ltd. A-3911 and the like.

[0104] The ultraviolet absorbing agent is contained in the first functional layer 12 in an amount of, for example, 0.05% by mass or more and 50% by mass or less. The ultraviolet absorbing agent may be contained in such a range. The ultraviolet absorbing agent can effectively absorb ultraviolet rays. In the case of a sol-based compound, the content of the compound in the first functional layer 12 is 0.1% by mass or more and 50% by mass or less. It may be contained.

[0105] The first functional layer 12 is, for example, a composition for a first functional layer including a polymerizable compound and an ultraviolet absorber. The first functional layer composition can be formed by using the above-mentioned polymerizable material. Compounds, etc., and also, if necessary, polymerization initiators, solvents, leveling, etc. This is also fine.

[0106] (Polymerization initiator) The polymerization initiator is not particularly limited, and any known polymerization initiator can be used. One type of polymerization initiator may be used, or two or more types may be used. , for example, acetophenones, benzophenones, Michler's benzoyl benzoate, α -Amyloxime esters, thioxanthones, propiophenones, benzils, benzos In addition, photosensitizers can be used in combination. Specific examples thereof include n-butylamine, triethylamine, polyamine, and the like. tri-n-butylphosphine and the like.

[0107] As the polymerization initiator, when the polymerizable compound has a radical polymerizable functional group, acetonitrile may be used. Tophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether It is preferable to use a radical polymerization initiator such as ether alone or in combination. Among the polymerization initiators, 2,4,6-trimethylsilyl 2,4,6-triphenylphosphine is preferred because it suppresses the inhibition of curing caused by UV absorption. Methylbenzoyldiphenylphosphine oxide (e.g., IGM Resins B. Omnirad TPO manufactured by V. Nylphosphine oxide (e.g., Omnira from IGM Resins BV) d819), 1-hydroxycyclohexyl phenyl ketone (e.g., IGM Resi ns BV's Omnirad184), oligo(2-hydroxy-2-methyl- 1-(4-(1-methylvinyl)phenyl)propanone (ES from DKSH Japan) ACURE ONE) or a mixture thereof is more preferred.

[0108] In addition, when the polymerizable compound has a cationic polymerizable functional group, the polymerization initiator may be , aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metallocene Cationic polymerization initiators such as benzoin sulfonate esters, etc., can be used alone or in mixtures. Among the cationic polymerization initiators, aromatic stearate is preferably used because of its excellent curing properties. Sulfonium salts and the like are more preferred.

[0109] In addition, when the light-transmitting substrate 11 contains a cycloolefin polymer resin, It is important that the first functional layer 12 is closely attached to the light-transmitting substrate 11. In order to adhere 12 to the light-transmitting substrate 11, an oxime ester-based polymerization initiator is used. It is preferable to use a compound such as the oxime ester compound. RGACURE® OXE01, IRGACURE® OXE02, I RGACURE (registered trademark) OXE03 (both manufactured by BASF Japan Ltd.) .

[0110] The content of the polymerization initiator in the composition for the first functional layer is 100 mass % of the polymerizable compound. The content of the polymerization initiator is preferably 1 part by mass or more and 10 parts by mass or less relative to the total mass of the polymerizable composition. If the amount is 1 part by mass or more, the hardness of the first functional layer becomes sufficient, and if the amount is 10 parts by mass or less, If the coating is applied, ionizing radiation penetrates deep into the coating, promoting internal curing and achieving the desired optical filter. The hardness of the surface of the mold (for example, a pencil hardness of 3B or more, as described below) 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 preferably 8 parts by mass or more. It is more preferable that the content of the photopolymerization initiator is within this range. Therefore, no distribution of hardness occurs in the film thickness direction, and the hardness tends to be uniform.

[0112] (solvent) The solvent to be used should be selected depending on the type and solubility of the polymerizable compound to be used. For example, ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone) , cyclohexanone, diacetone alcohol, etc.), ethers (dioxane, tetrahydrofuran, Lofuran, Propylene Glycol Monomethyl Ether, Propylene Glycol Monomethyl ether acetate, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclo Hexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated carbons (dichloro chloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.) , water, alcohols (ethanol, isopropanol, butanol, cyclohexanol etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetate sulfoxides (dimethyl sulfoxide, etc.), amides (dimethylformamide, di methylacetamide, etc.) and the like, and a mixed solvent of these 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 silicon-based leveling agent, it has high leveling properties, making it smooth and easy to recoat. Commercially available fluorine-based leveling agents include F-555 (DIC Corporation) F-568 (manufactured by DIC Corporation), ... (manufactured by Neos Co., Ltd.)

[0114] The content ratio (solid content) of the raw materials in the composition for the first functional layer is not particularly limited, but The content is preferably 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 uniformly mixed. For example, a known device such as a paint shaker, a bead mill, a kneader, or a mixer may be used. This can be done.

[0116] The method for applying the composition for the first functional layer onto the light-transmitting substrate 11 is not particularly limited, and examples thereof include For example, spin coating, dip coating, spray coating, die coating, bar coating, roll coating, etc. Coater method, meniscus coater method, flexographic printing method, screen printing method, pad coater The above-mentioned known methods include the above-mentioned method.

[0117] The ionizing radiation source used for curing the composition for the first functional layer is mainly 190 to 450 n The ionizing radiation source is preferably an ultra-high-energy source having an emission peak in the wavelength range of 1000 nm. mercury vapor lamp, high pressure mercury vapor lamp, low pressure mercury vapor lamp, carbon arc lamp, black light fluorescent lamp, metal Examples of light sources include a halide lamp.

[0118] <<Second functional layer>> The second functional layer 13 is a hard coat layer. However, the second functional layer 13 may have other functions. The "hard coat layer" in this embodiment may be a layer having an indentation function. The second functional layer has a higher indentation hardness than the first functional layer. The indentation hardness of the functional layer was determined in the same way as the indentation hardness of the first functional layer. do.

[0119] The indentation hardness of the second functional layer 13 is 75 MPa or more and 1000 MPa or less. It is preferable that the indentation hardness of the second functional layer 13 is 75 MPa or more. If the hardness is 1000 MPa or less, the desired pencil hardness can be obtained. The lower limit of the indentation hardness of the second functional layer 13 is a higher pencil hardness. From the viewpoint of obtaining the desired strength, the pressure should be 100MPa or more, 150MPa or more, or 200MPa or more. The upper limit of the indentation hardness of the second functional layer 13 is preferably set to 0.5 to 1.0. From the viewpoint of suppressing generation, 900MPa or less, 750MPa or less, 600MPa or less The indentation strength of the second functional layer 13 is preferably 500 MPa or less. If the hardness is 600 MPa or less, the second functional layer 13 having excellent flexibility can be obtained. do.

[0120] The thickness of the second functional layer 13 is preferably 0.1 μm or more and 9.8 μm or less. If the thickness of the functional layer 13 is 0.1 μm or more, a desired pencil hardness can be ensured. If the thickness of the layer 13 is 9.8 μm or less, it is possible to make the layer thinner and to make it easier to bend. The occurrence of cracks during bending or curving can be suppressed. From the viewpoint of obtaining a higher pencil hardness, the thickness is set to 0.3 μm or more, 0.5 μm or more, or 1 μm or more. If the thickness of the second functional layer 13 is 0.5 μm or more, scratches during the production process are prevented. The upper limit of the thickness of the second functional layer 13 is set to 100%. From the viewpoint of achieving this, the thickness should be 8 μm or less, 5 μm or less, 4 μm or less, or 3 μm or less. The thickness of the second functional layer 13 can be determined in the same manner as the first functional layer 12. can.

[0121] The second functional layer 13 contains a resin and an ultraviolet absorbing agent. In the case where the second functional layer 13 contains an ultraviolet absorbing agent, the second functional layer 13 does not necessarily need to contain an ultraviolet absorbing agent. Furthermore, when the optical film 10 is wound into a roll, the optical film 10 is adhered to itself. The second functional layer 13 may contain an anti-blocking agent to prevent the blocking. The resin includes a polymer of a polymerizable compound. In addition, the resin may contain a solvent drying type resin or a thermosetting compound.

[0122] The concentration of the ultraviolet absorbing agent in the second functional layer 13 is lower than the concentration of the ultraviolet absorbing agent in the first functional layer 12. It is preferable that the concentration of the ultraviolet absorbing agent in the second functional layer 13 is lower than that in the first functional layer 13. The concentration of the ultraviolet absorbing agent in the layer 12 is lower than that in the layer 13, thereby preventing the bleeding out of the ultraviolet absorbing agent. This can reduce the scratch resistance of the surface of the second functional layer 13, thereby further improving the scratch resistance.

[0123] The polymerizable compound constituting the second functional layer 13 may be a polymerizable monomer or a polymerizable oligomer. or a polymerizable prepolymer, which can be appropriately adjusted and used. The polymerizable compound may be a polymerizable monomer, a polymerizable oligomer, or a polymerizable prepolymer. A combination with is preferred.

[0124] Examples of the polymerizable monomer 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 Lithylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate Tetraethylene glycol di(meth)acrylate, tetramethylene glycol di(meth)acrylate Acrylate, Trimethylolpropane Tri(meth)acrylate, Trimethylolethane Pentaerythritol tri(meth)acrylate, Pentaerythritol di(meth)acrylate, Pentaerythritol Erythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate Dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate (Meth)acrylic acids such as hexa(meth)acrylate and glycerol(meth)acrylate Examples include esters.

[0125] The polymerizable oligomer is preferably a polyfunctional oligomer having two or more functional groups. The polyfunctional oligomer is preferably a polyfunctional oligomer having three or more functional groups. For example, polyester (meth)acrylate, urethane (meth)acrylate, polyester Ter-urethane (meth)acrylate, polyether (meth)acrylate, polyol (Meth)acrylate, melamine (meth)acrylate, isocyanurate (meth)acrylate acrylate, epoxy (meth)acrylate, etc.

[0126] The polymerizable prepolymer has a weight average molecular weight of more than 10,000. The weight average molecular weight is preferably from 10,000 to 80,000, and more preferably from 10,000 to 40,000. If the viscosity exceeds 80,000, the coating suitability decreases due to high viscosity, and the obtained light-transmitting resin The appearance of the oil may be deteriorated. acrylate, isocyanurate (meth)acrylate, polyester-urethane (meth)acrylate acrylate, epoxy (meth)acrylate, etc.

[0127] <Ultraviolet absorbing agent> The ultraviolet absorbing agent is the same as the ultraviolet absorbing agent described in the section of the first functional layer 12. Since it can be used, the description will be omitted here.

[0128] The second functional layer 13 is formed by using a composition for the second functional layer containing a polymerizable compound or the like. The composition for the second functional layer can be formed by using a polymerizable compound and an ultraviolet absorber. The ink may contain a solvent drying type resin, a thermosetting compound, a polymerization initiator, a solvent, etc. The composition for the functional layer may contain various additives as required, as long as they do not impair the effects of the present invention. Such additives may include, for example, inorganic particles, antistatic agents, adhesives, etc. Adhesion improver, leveling agent, thixotropy agent, coupling agent, plasticizer, defoamer, filler , colorants, etc.

[0129] The composition for the second functional layer is a mixture of a solvent-drying resin, a thermosetting compound, a polymerization initiator, a solvent, and a leveling agent. The binder and the like are the solvent drying type resin, the thermosetting compound, the polymerizable compound, and the like, which are described in the first functional layer composition. Since these are similar to the initiator, solvent, leveling agent, etc., the description thereof will be omitted 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. However, it is preferable that they are different. The polymerization initiator in the composition for the first functional layer is different from the polymerization initiator in the composition for the first functional layer. In the composition for the second functional layer, a polymerization initiator that is easy to semi-cure is selected. A polymerization initiator having good surface curing 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 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. Whether or not the components of the first functional layer 12 and the second functional layer 13 are included is determined by time-of-flight secondary ion spectroscopy. 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 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 first and second functional layers 13. For example, the mixed layer 14 is a layer formed on the surface of the first functional layer 12 by mixing the components of the first functional layer 12 and the second functional layer. The layer 13 may be formed by applying a composition containing the components of the layer 13. In a semi-cured state, a composition for a second functional layer is applied to the surface of the coating film. However, in order to further improve the adhesion and to achieve a thinner structure, In a semi-cured state, a coating film of the composition for the first functional layer is coated on the surface of the coating film with a composition for the second functional layer. It is preferable to form the first functional layer by applying the composition for the first functional layer, which will be described later. In a semi-cured state of the first coating film 21, a composition for a second functional layer is applied to the surface of the first coating film 21. When a mixed layer is formed by the above method, the reason is unclear, but The solvent penetrates into the semi-cured coating, and the polymerizable compound components are also absorbed into the semi-cured post-coating. It is believed that the particles are 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 It is preferable that 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 a concentration gradient can be confirmed by TOF-SIMS. The mixed layer 14 having a degree distribution is formed by semi-curing the coating of the composition for the first functional layer. The second functional layer can be formed by applying a composition for the second functional layer to the surface of the first functional layer.

[0134] The thickness of the mixed layer 14 relative to the total thickness of the first functional layer 12, the second functional layer 13 and the mixed layer 14 The ratio of thickness (thickness of mixed layer 14) / (thickness of first functional layer 12+thickness of second functional layer 13+thickness of mixed layer It is preferable that the thickness (thickness of 14) × 100) is 0.6% or more and 40% or less. If it is 0.6% or more, the adhesion before the durability test (initial adhesion) will be good. Since the layer is relatively soft, if the above ratio is too high, the optical film will become soft. If the above ratio is 40% or less, the reduction in the surface hardness of the optical film 10 can be prevented. The lower limit of the above ratio improves not only the initial adhesion but also the adhesion after the durability test. From this viewpoint, it is preferable that the content be 1% or more, 3% or more, 5% or more, or 10% or more. The upper limit of the film thickness of the above ratio is set to 35% or less, 30% or less, or 20% or less from the viewpoint of thinning. It is preferable that the temperature is lower than the above range.

[0135] The thickness of the mixed layer 14 is preferably 0.02 μm or more and 3 μm or less. If the thickness is 0.02μm or more, the initial adhesion is good, and if it is 3μm or less, In this way, it is possible to suppress a decrease in the surface hardness of the optical film 10. Therefore, the lower limit of the thickness of the mixed layer 14 is set not only in terms of the initial adhesion but also in terms of the adhesion after the durability test. From the viewpoint of improving adhesion, 0.1 μm or more, 0.2 μm or more, or 0.4 μm or more The upper limit of the thickness of the mixed layer 14 is set so as to prevent a decrease in the surface hardness of the optical film 10. From the viewpoint of suppressing the above, the thickness is more preferably 2 μm or less or 1 μm or less. The thickness of the first functional layer 4 can be adjusted by adjusting the degree of semi-curing of the first functional layer 12. That is, when the degree of semi-curing of the first functional layer 12 is reduced, the thickness of the mixed layer 14 is increased. When the degree of semi-curing is increased, the thickness of the mixed layer 14 is decreased.

[0136] <<Optical film manufacturing method>> The optical film 10 can be produced, for example, as follows. As shown in FIG. 1A, a first functional layer composition is applied to one surface 11A of a light-transmitting substrate 11. Then, as shown in FIG. 4(B), Then, the first coating film 21 is irradiated with ionizing radiation such as ultraviolet light to polymerize (crosslink) the polymerizable compound. In this specification, the term "semi-curing" refers to a process in which the first coating film 21 is semi-cured by applying ionizing radiation. This means that further exposure to radiation will result in substantial further cure.

[0137] After the first coating film 21 is semi-cured, a second functional layer composition is applied to the surface of the first coating film 21; When dried, as shown in FIG. 5(A), in addition to the second coating film 22, the first coating film 21 and the second coating film 22 are formed. A mixed coating film 23 containing the components of the first coating film 21 and the second coating film 22 is formed between the coating films 22. do.

[0138] Next, as shown in FIG. 5(B), the first coating film 21, the second coating film 22 and the mixed coating film 2 3 is irradiated with ionizing radiation such as ultraviolet light to polymerize (crosslink) the polymerizable compound. The first coating film 21, the second coating film 22 and the mixed coating film 23 are cured (for example, completely cured). In the specification, "complete curing" means that the curing will not progress substantially even if the material is further irradiated with ionizing radiation. This means that the first functional layer 12, the second functional layer 13, and the first functional layer Since a mixed layer 14 is formed between the first functional layer 12 and the second functional layer 13, an optical film 10 is obtained. .

[0139] According to this embodiment, the total thickness of the first functional layer 12, the second functional layer 13 and the mixed layer 14 is Since the thickness of the first functional layer 1 is 1 μm or more and 10 μm or less, it is possible to achieve a thin structure. When at least one of the first functional layer 12 and the second functional layer 13 contains an ultraviolet absorbent, Between the functional layer 12 and the second functional layer 13, adjacent to the first functional layer 12 and the second functional layer 13, The thickness of the mixed layer 14 relative to the total thickness of the first functional layer 12, the second functional layer 13 and the mixed layer 14 Since the mixed layer 14 is formed with a thickness ratio of 0.6% to 40%, the surface hardness is low. The adhesion between the first functional layer 12 and the second functional layer 13 can be improved. This can be done.

[0140] According to this embodiment, at least one of the first functional layer 12 and the second functional layer 13 is purple. In the case where the ultraviolet ray absorbing agent is contained, the first functional layer 1 is disposed between the first functional layer 12 and the second functional layer 13. 2 and a mixed layer adjacent to the second functional layer 13 and having a thickness of 0.02 μm or more and 1 μm or less. Since the first functional layer 12 and the second functional layer 14 are formed, the decrease in surface hardness can be suppressed. The adhesion between the functional layers 13 can be improved.

[0141] According to this embodiment, the light-transmitting substrate 11 is made of an acetyl cellulose-based resin, a cycloolefin resin, Since the light-transmitting substrate 1 contains an indole-based polymer resin or a (meth)acrylic resin, The in-plane retardation Re of 1 is at most about 150 nm. This makes it possible to suppress a decrease in visibility when observing a displayed image.

[0142] <<<Polarizing plate>>> The optical film 10 can be incorporated into a polarizing plate for use. As shown in FIG. 6, the polarizing plate 30 has an optical filter. The polarizing plate 3 is provided with a film 10, a polarizer 31, and a protective film 32 in this order. In FIG. 0, a 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, The plates are attached together using a type of adhesive or an ultraviolet-curing adhesive.

[0144] <<Polarizer>> The polarizer 31 is provided on the surface of the light-transmitting substrate 11 opposite to the surface on the first functional layer 12 side. The polarizer 31 is a uniaxially stretched polarizer dyed with iodine or a dichroic dye. Examples of polyvinyl alcohol-based resins include polyvinyl alcohol-based resin films. For the purpose, a saponified polyvinyl acetate resin can be used. As for fats, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, vinyl acetate and its copolymers are also used. Other monomers that can be copolymerized with vinyl acetate include copolymers with other monomers that can be copolymerized with vinyl acetate. Examples of the compounds include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated s Examples of the polyvinyl alcohol include polyvinyl alcohols and acrylamides having an ammonium group. The cholesteric resin may be modified, for example, polyvinyl modified with aldehydes. Formal, polyvinyl acetal, etc. can also be used.

[0145] <<Protective film>> The protective film 32 may be, for example, a triacetyl cellulose film or a (meth)acetyl cellulose film. Examples of the film include acrylic resin film and cycloolefin polymer film.

[0146] <<<Image display devices>>> The optical film 10 or the polarizing plate 30 can be incorporated into an image display device. FIG. 7 is a schematic diagram of an image display device according to this embodiment. The image display device 40 includes a display element 50, a circular polarizing plate 60, and a touch sensor 61 facing the observer side. The display device 50 includes a circular polarizer 60 and a cover member 80 in this order. The polarizing plate 60 and the touch sensor 70, and the touch sensor 70 and the cover member 80 are bonded to each other. The layers 91 to 93 are bonded together. In this specification, the term "bonding" includes adhesion. be.

[0147] <<<Display element>>> The display element 50 may be a liquid crystal element, an organic light-emitting diode element (hereinafter referred to as an "OLED element"). ), inorganic light-emitting diode elements, micro LEDs, plasma elements, etc. As the organic light-emitting diode element, a known organic light-emitting diode element is used. In addition, the liquid crystal display element can be an in-cell touch panel having a touch panel function inside the element. It may be a panel liquid crystal display element.

[0148] <<<Circular polarizing plate>>> The circular polarizer 60 has a function of suppressing reflection of external light, so that an OLED device as a display device The circular polarizer 60 is particularly effective when the circular polarizer 60 is used on the viewer side. A first retardation film 61 (hereinafter, also referred to simply as "retardation film 61") is provided for the above-mentioned purpose. ), an adhesive layer 62, and a second retardation film 63 (hereinafter, simply referred to as "retardation film 63"). "), an adhesive layer 64, and a polarizing plate 30, in that order.

[0149] In the circularly polarizing plate 60, the second functional layer 13 of the optical film 10 is thicker than the first functional layer 12. By arranging the polarizing plate 30 in this manner, a desired pencil hardness can be obtained. and scratch resistance can be obtained.

[0150] The thickness of the circularly polarizing plate 60 is preferably 100 μm or less in order to reduce the thickness. The lower limit of the thickness of the circularly polarizing plate 60 is 20 μm or more, and 30 μm or less from the viewpoint of workability due to a decrease in strength. The upper limit of the thickness of the circularly polarizing plate 60 is preferably 100 μm or more, more preferably 50 μm or more. More preferably, the thickness is 95 μm or less, 90 μm or less, or 80 μm or less. The thickness of the circular polarizing plate 60 was measured by photographing a cross section of the circular polarizing plate 60 using a scanning electron microscope (SEM). The thickness of the circularly polarizing plate 60 was measured at 10 points in the cross-sectional image, and the arithmetic average of the thicknesses at the 10 points was calculated. It can be found by taking the average.

[0151] The circular polarizing plate 60 is manufactured by either the chip-cut method or the roll-to-panel method. The chip-cut method can be used to cut the chip to fit the size of the image display device. Then, a circular polarizing plate of a predetermined size is cut out from the rolled circular polarizing plate, and the plate is attached to the glass via an adhesive layer. The roll-to-panel method is a method in which the image is attached to a cover material such as a glass. In the manufacturing line of the display device, a roll of circularly polarizing plate is cut while being fed out, and the plate is attached to the adhesive layer. The film is then attached to a cover material such as glass.

[0152] <<First Retardation Film>> The retardation film 61 is a positive C plate or a λ / 4 retardation film. There can be.

[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 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 property 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] 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 and cellulose-based resins. The λ / 4 retardation film having negative wavelength dispersion can be obtained, for example, by polycarbonate-based resins and resins having an aromatic structure. ​​​​​​​​​​​

[0157] <<adhesive layer>> The adhesive layers 62 and 64 are made of a liquid ionizing radiation curable adhesive containing a polymerizable compound (e.g., O Cured products of CR: Optically Clear Resin and adhesives (e.g. OCA: Optical Clear Adhesive) The thickness of the adhesive layers 62 and 64 can be 0.5 μm or more and 5 It is preferable that the thickness is 0 μm or less.

[0158] <<Second retardation film>> When the retardation film 61 is a positive C plate, the retardation film 63 is For this purpose, a λ / 4 retardation film having negative wavelength dispersion (reverse wavelength dispersion) can be used. When the retardation film 61 is a λ / 4 retardation film, a λ / 2 retardation film is used. Room can be used.

[0159] <λ / 4 Retardation Film with Negative Wavelength Dispersion> As the λ / 4 retardation film having negative wavelength dispersion, Since this is similar to the λ / 4 retardation film with negative wavelength dispersion described in the section, The explanation will be omitted.

[0160] <λ / 2 phase difference film> A λ / 2 retardation film is a film that has a specific wavelength of light (usually in the visible light region). This film has the characteristic that the in-plane retardation is about 1 / 2. By placing a λ / 2 retardation film on the It is possible.

[0161] The λ / 2 retardation film is produced by stretching a resin film while adjusting the stretch ratio. The resin constituting the resin film for obtaining the λ / 2 retardation film is Examples of the resin include polycarbonate resins and cycloolefin polymer resins. can be.

[0162] <<<Touch sensor>>> A known touch sensor can be used as the touch sensor 70. The type of 70 is not particularly limited, but for example, a capacitive touch sensor may be used. The touch sensor 70 is disposed between the circular polarizer 60 and the cover member 80. However, it may be disposed between the display element 50 and the circular polarizer 60 .

[0163] <<<Cover parts>>> The surface 80A of the cover member 80 is the surface 40A of the image display device 40. The member 80 may be a cover glass or a cover film made of resin. In the case where the device 40 is flexible, the cover member 80 is made of flexible glass or flexible The resin having flexibility is preferably, for example, , polyimide resin, polyamideimide resin, polyamide resin, polyester resin (e.g., polyethylene terephthalate resin or polyethylene naphthalate resin), or A mixture of two or more of these resins may be used.

[0164] <<<adhesive layer>>> The adhesive layers 91 to 93 are made of a liquid ionizing radiation curable adhesive containing a polymerizable compound (e.g., O Cured products of CR: Optically Clear Resin and adhesives (e.g. OCA: Optical Clear Adhesive) It is possible to construct it from the

[0165] OLED elements are at risk of deterioration due to external light, etc. For this reason, currently, OLED elements In image display devices using OLED elements, it is desirable to suppress the degradation of the OLED elements. OLED elements also emit light called blue light. Blue light has a wavelength that It has a wavelength range of 380nm to 500nm and has properties similar to ultraviolet rays, and has strong energy. Since it has a hydroxyl group, it can reach the retina without being absorbed by the cornea or lens, causing retinal damage and It is said that blue light can cause eye fatigue and have a negative effect on sleep. According to this embodiment, the display element 50 is an OLED element. In some cases, the first functional layer 12 containing an ultraviolet absorbing agent is provided on the viewer side of the OLED element. Therefore, the first functional layer 12 can absorb ultraviolet light from outside light. It can suppress the deterioration of OLED elements due to external light. In addition, it can also suppress the deterioration of OLED elements due to ultraviolet light emitted from OLED elements. It can absorb blue light, so it can block it.

[0166] According to this embodiment, when the display element 50 is an OLED element, the display element 50 is more visible than the OLED element. The investigator was exposed to at least one sesamol-type benzotriazole compound and an indole compound. Since the first functional layer 12 includes either one of the above, the ultraviolet ray of the external light is absorbed by the first functional layer 12. It can absorb external radiation, which can prevent deterioration of OLED elements caused by external light. At the same time, it can block the blue light emitted from OLED elements.

[0167] According to this embodiment, the polarizer 31 includes an ultraviolet absorbing agent that absorbs ultraviolet light on the viewer side. Since the display element 50 includes the first functional layer 12, when the display element 50 is an OLED element, the OLED This can suppress deterioration of not only the element but also the polarizer due to external light.

[0168] Even when the adhesive layer contains the above-mentioned UV absorber, deterioration of OLED elements caused by external light is suppressed. It is possible to block blue light while at the same time, but if the adhesive layer contains an ultraviolet absorbing agent, The adhesive strength is easily reduced. For this reason, it is difficult to make the adhesive layer thinner. Depending on the structure of the board, the type of adhesive layer may be changed, so the UV absorption In contrast, in the present embodiment, the indentation hardness is When the ultraviolet absorbing agent is contained in the first functional layer 12 having a resistance of 50 MPa or more and 600 MPa or less, In this way, it is possible to reduce the thickness of the first functional layer 12. In addition, by adding an ultraviolet absorbing agent to the first functional layer 12, Therefore, even if the type of adhesive layer is changed depending on the configuration of the circularly polarizing plate 60, etc. This can be achieved with one functional layer 12.

[0169] [Second embodiment] The optical film and the image display device according to the second embodiment of the present invention will be described below with reference to the drawings. The description will be given with reference to FIG. 8, which is a schematic diagram of the optical film according to the present embodiment. FIG. 9 is a partially enlarged view of the optical film of FIG. 8, and FIG. 10 shows the position where the in-plane retardation is measured. 11 and 12 are plan views of a sample for identifying the optical element according to the present embodiment. FIG. 2 is a diagram illustrating a film manufacturing process.

[0170] <<<<Optical films>>>> The optical film 100 shown in FIG. 8 includes a light-transmitting substrate 101 and a functional layer 102. The functional layer 102 contains an ultraviolet absorbing agent containing nitrogen atoms. The functional layer 102 is adjacent to the light-transmitting substrate 101, but the light-transmitting substrate 101 and the functional layer 10 2, other functional layers may be provided between them.

[0171] The surface 100A of the optical film 100 shown in FIG. 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 filter In this specification, the term "surface of a functional layer" refers to the surface of a functional layer. In this case, the surface on the light-transmitting substrate side means the surface on the opposite side.

[0172] Thickness (total thickness) of the optical film 100, spectral transmittance, yellow index, total light Transmittance, haze value, pencil hardness, and other physical properties and their measurement methods, flexibility, and The evaluation method and the use and size of the optical film 100 are as follows: , spectral transmittance, yellow index, total light transmittance, haze value, pencil hardness and other physical properties and its measuring method, flexibility and its evaluation method, and use of optical film 10 The method and size are the same, so the explanation will be omitted here.

[0173] <<<Light transparent base material>>> The light-transmitting substrate 101 is a substrate having light-transmitting properties. Although there is no particular limitation, in terms of adhesion between the light-transmitting substrate 101 and the functional layer 102, When forming the functional layer 102, the components of the functional layer 102 (for example, a polymerizable compound) penetrate into the functional layer 102 through a penetration hole. It may be a permeable substrate.

[0174] The material of the light-transmitting substrate is not particularly limited, and may be, for example, an acetyl cellulose resin. olefin resin, cycloolefin polymer resin, (meth)acrylic resin, polyester resin, Polyolefin resin, polyethersulfone resin, polycarbonate resin, polya Imide resin, polyimide resin, polyamide-imide resin, polyvinyl chloride resin, poly Vinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyaryl Examples of the resin include light-transmitting resins such as polyphenylene sulfide resins and mixtures of these resins. As described in the first embodiment, when a displayed image is observed through polarized sunglasses, Since the decrease in visibility can be suppressed even in the presence of acetyl cellulose resin, cyclohexyl ester resin, Refine polymer resins or (meth)acrylic resins are preferred. From this viewpoint, polyimide resins and polyamide resins are more preferable. If necessary, various additives such as a plasticizer, an ultraviolet absorbing agent, and a lubricant may be added.

[0175] Acetyl cellulose resin, cycloolefin polymer resin, (meth)acrylic resin The grease has been described in the first embodiment, so a description thereof will be omitted here.

[0176] Examples of polyester resins include polyethylene terephthalate (PET), poly Ethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene Examples of the resin include those containing at least one of polyphenylene naphthalate (PBN) as a constituent. When ester resin is used, it has the property of emitting fluorescence when excited by ultraviolet light. It is known that such fluorescence can affect the color of the display surface. As described above, the optical film 10 blocks almost all light having a wavelength of 380 nm or less. Therefore, even if a polyester resin is used for the light-transmitting substrate 11, fluorescence is not generated. This can be suitably prevented.

[0177] Examples of polyolefin resins include polyethylene and polypropylene. Examples of polycarbonate resins include bisphenols (such as bisphenol A). ) based aromatic polycarbonate, diethylene glycol bisallyl carbonate Examples of the polycarbonate include aliphatic polycarbonates such as tungsten.

[0178] The polyimide resin may be an aliphatic polyimide resin, but may also be an aromatic polyimide resin containing an aromatic ring. The aromatic polyimide resin is preferably a tetracarbocyclic polyimide resin. At least one of the diamine component and the dicarboxylic acid component contains an aromatic ring.

[0179] The polyimide resin may partially contain a polyamide structure. Examples of suitable polyamide structures include tricarboxylic acid residues such as trimellitic anhydride. and polyamide-imide structures containing dicarboxylic acid residues such as terephthalic acid. Polyamide resins include not only aliphatic polyamides but also aromatic polyamides. It is a concept that includes mido (aramid).

[0180] The thickness of the light-transmitting substrate 101 (when the optical film 100 is required to be flexible) The thickness of the light-transmitting substrate 101 and the method of measuring the thickness and the surface treatment are The thickness of the substrate 11 and the method for measuring the thickness are the same as those of the surface treatment. In addition, when the light-transmitting base material 101 contains a polyester resin, In the case where the optical film 100 is required to have flexibility, the optically transparent substrate The thickness of 101 is similar to the thickness of the light-transmitting substrate 11 containing a cycloolefin polymer resin. It is.

[0181] When the light-transmitting substrate 101 contains a polyester-based resin, the polyester in the light-transmitting substrate 101 The more uniform the mer, the better the flexibility. When it contains fat, stretching is essential to obtain physical strength, so the polymer state is In order to make it as uniform as possible, it is manufactured by sequential or simultaneous biaxial stretching at approximately the same magnification in both the length and width directions. As a result, the in-plane retardation is smaller than that of a conventional light-transmitting substrate containing a polyester resin. A light-transmitting substrate containing a polyester resin is obtained. The term "small in-plane retardation" in a transparent substrate refers to a light-transmitting substrate containing a polyester resin. The thickness is in the range of 10 μm to 90 μm, and the in-plane retardation is 1500 nm or less. It is preferably 1200 nm or less, more preferably 1000 nm or less, and even more preferably Preferably, the wavelength is 800 nm or less. In order to improve the physical properties as a film, the in-plane retardation should not be too small. More preferably, it is 400 nm or more.

[0182] When the light-transmitting substrate 101 contains a polyester resin, the in-plane position of the light-transmitting substrate 101 The retardation is the refractive index in the slow axis direction, which is the direction in the plane of the light-transmitting substrate that has the largest refractive index. nx, the refractive index in the fast axis direction, which is a direction perpendicular to the slow axis direction in the plane, ny, and the thickness t (nm) of the light-transmitting substrate, which is expressed by the following formula (4): According to the following formula (4), since the in-plane retardation is small, the degree of orientation is low, and therefore the bending is difficult. It can be seen that the in-plane retardation (Re) can be improved by, for example, Product name of subsidiary company: "RETS-100" Product name of Oji Instruments: "KOBRA-WR" This can be measured using the "PAM-UHR100". In-plane phase difference (Re)=(nx-ny)×t…(4)

[0183] When measuring the above Re using the RETS-100, follow the procedure below. First, turn on the RETS-100 light source to stabilize it. Leave it for 60 minutes or more. After that, select the rotating analyzer method and the θ mode (angle direction position). By selecting this θ mode, the stage will rotate and tilt. This will be the stage.

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

[0185] Background data is then obtained without placing a sample in the instrument. This is a chain system, and is performed every time the light source is turned on.

[0186] Then, the sample is placed on the stage inside the device. The sample may be of any shape, for example rectangular. The sample size is 50 mm. If there are multiple samples, they should all be placed in the same orientation. For example, all samples must be marked in advance to ensure that they are all set in the same orientation. It is preferable to have it attached.

[0187] After placing the sample, the sample was placed in an environment of 23±5°C temperature and 50±20% relative humidity. Rotate the stage 360° on the plane to measure the fast and slow axes. Select the slow axis. Then, measure while tilting the stage within the set angle range around the slow axis. The tilt angle and wavelength range (Re) are set in 10° increments. The in-plane retardation Re is the value measured with light at an incident angle of 0° and a wavelength of 589 nm. The in-plane retardation Re is measured at five different positions. Draw two orthogonal imaginary lines IL1 and IL2 passing through the center A1 of the sample S2 so that Drawing these imaginary lines IL1 and IL2 divides the sample into four sections. In the image, set one point equidistant from the center A1, and a total of four points A2 to A4. The measurement is taken at five points in total, A1, B2, C3, C4, and A5. The maximum and minimum values ​​are excluded from the five measurement points. The arithmetic average value of the three points is defined as the in-plane retardation Re.

[0188] In order to further improve the physical properties, the birefringence in the film thickness direction as well as the birefringence in the in-plane direction should be increased. The balance between the two should also be considered. The Nz coefficient is an indicator of the light transmittance. Since it is affected by the crystallinity and orientation inside the substrate, it is related to the properties of the entire light-transmitting substrate. For example, the Nz coefficient for polyethylene terephthalate is generally 2 to 4. However, in the present invention, it is preferably 5 or more, more preferably 8 or more, and most preferably 10 or more. The upper limit of the Nz coefficient is about 80, preferably 70 or less, and most preferably 50 or less. The Nz coefficient is calculated by the following formula ( In the following formula (5), nx and ny are expressed as follows: This is the same as nx and ny in equation (4) above. Nz coefficient=(nz-nx) / (ny-nx) …(5)

[0189] <<<Functional Layer>>> The functional layer 102 shown in FIG. 8 has a single-layer structure, but may have a multi-layer structure of two or more layers. The functional layer 102 is a layer that functions as a hard coat layer. The layer 102 may have other functions. "The indentation hardness is greater than the indentation hardness of the light-transmitting substrate. This refers to the layer

[0190] The thickness of the functional layer 102 is 1 μm or more and 10 μm or less. By keeping the thickness within this range, a thinner film can be achieved. The upper limit of the film thickness is 9 μm. It may be 8 μm or less, or 7 μm or less.

[0191] In this embodiment, the "film thickness of the functional layer" refers to the light transmission due to the contrast difference of a microscope image. The interface line between the functional layer and the substrate can be recognized, and the area from the interface line to the surface of the functional layer can be measured. The thickness of the functional layer is measured by scanning electron microscope (SEM) and transmission electron microscope ( A cross-section of the functional layer is photographed using a TEM or a scanning transmission electron microscope (STEM), The thickness of the functional layer was measured at 10 points in the cross-sectional image, and the arithmetic average of the thicknesses at those 10 points was calculated. The specific method for taking cross-sectional photographs is as described in the first embodiment. The method for taking cross-sectional photographs is the same as that described in the embodiment, so the explanation will be omitted here. do.

[0192] In the functional layer 102, time-of-flight secondary ion mass spectrometry (TOF-SIMS) When the intensity of the secondary ions is measured in the depth direction D1 of the functional layer 102, The ultraviolet absorbing agent-derived first region 102C (see FIG. 9) having a thickness of 0.3 μm including 02A Secondary ion intensity I U1 The functional layer 102 is divided into two equal parts in the depth direction D1 of the functional layer 102. In the second region 102D (see FIG. 9) having a thickness of 0.3 μm and including the bisector IL (see FIG. 9), Intensity of secondary ions originating from ultraviolet absorbers in I U2 The ratio (I U2 / I U1 ) is 1.1 or more 4.0 or less, and the intensity of the secondary ions originating from the ultraviolet absorber in the second region 102D I U2 The third region 102E ( Intensity I of secondary ions originating from the UV absorber (see Fig. 9) U3 The ratio (I U3 / I U2 ) is between 1.2 and 4.0. U2 / I U1 If is 1.1 or more, the first region 102C does not contain too much UV absorbent, so the surface hardness and scratch resistance are less likely to decrease. This can suppress the deposition of the ultraviolet absorbing agent. U2 / I U1 4. If the concentration is 0 or less, there is an extreme concentration of the ultraviolet absorbing agent between the first region 102C and the second region 102D. The second region 102C contains more ultraviolet absorbing material than the first region 102C. This prevents 102D from becoming too soft, reducing the decrease in surface hardness and the occurrence of defects during durability tests. This makes it possible to suppress cracks caused by the difference in thermal contraction between the first region 102C and the second region 102D. I U3 / I U2 If the ratio is 1.2 or more, the amount of the ultraviolet absorbing agent contained in the second region 102D is large. Therefore, the precipitation of the ultraviolet absorbing agent can be further suppressed. U3 / I U2 is 4.0 or less If this is the case, an extreme difference in concentration of the ultraviolet absorbing agent will occur between the second region 102D and the third region 102E. Therefore, the third region 102E, which contains more ultraviolet absorbing agent than the second region 102D, This can prevent the second region 10 from becoming too soft, and can prevent a decrease in surface hardness and a decrease in the durability test. Cracks caused by the difference in thermal contraction between the 2D and third regions 102E can be suppressed. U2 / I U1 The lower limit of is more preferably 1.2 or more, 1.3 or more, or 1.4 or more, The upper limit must be 3.5 or less, 3.0 or less, 2.5 or less, 2.0 or less, or 1.6 or less. It is more preferable that U3 / I U2 The lower limit is 1.3 or more, 1.4 or more, and 1.6 or less. More preferably, the upper limit is 3.5 or less, 3.2 or less, or 2.0 or more. More preferably, it is 0.8 or less, 2.6 or less, or 2.5 or less.

[0193] Intensity I of secondary ions originating from the ultraviolet absorber in the first region 102C U1 Third Territory for Intensity of secondary ions originating from ultraviolet absorbers in region 102E IU3 The ratio (I U3 / I U1 ) It is preferable that the ratio is 1.5 or more and 6.5 or less. U3 / I U1 is 1.5 or more If so, the amount of the ultraviolet absorbing agent contained in the first region 102C is not too large, so that the surface hardness and abrasion resistance are improved. This can further suppress the deterioration of scratch resistance and the precipitation of the ultraviolet absorbing agent. U 3 / I U1 If the ratio is 6.5 or less, the third region 102E can be prevented from becoming too soft. This prevents the surface hardness from decreasing. U3 / I U1 The lower limit is 1.8 or more, 2.0 or more, or 2.2 or more, and the upper limit is 6.2 or less, 6.0 or less, or 5. .8 or less is more preferable.

[0194] The horizontal axis of the TOF-SIMS depth profile is the depth, but this depth is the functional layer. Since this is the depth calculated from the etching rate, the film thickness of the functional layer obtained from the cross-sectional photograph above The thickness and thickness of each region, and the film thickness and each region of the functional layer on the depth profile must be The above "bisecting line that divides the functional layer in the depth direction of the functional layer" is , an imaginary line that bisects the film thickness of the functional layer in the depth direction of the functional layer, and the depth profile The above "reverse side of the functional layer" is determined based on the thickness of the functional layer obtained from the above data. The intensity of the secondary ions originating from the light-transmitting substrate and the secondary ions originating from the UV absorber in the pass profile was The thickness of the first region, the thickness of the second region, and the thickness of the third region are also intersected. The thickness of the region is also determined from the depth profile. Unless otherwise specified, the "intensity of secondary ions" refers to at least one secondary ion with different depths in each region. The intensity is the arithmetic average value of the intensities measured at three points. The second region 102D extends in a direction D2 (see FIG. 9) perpendicular to the direction D1. The isolating line IL is set to be located at the center of the second region 102D.

[0195] The secondary ion intensity was measured using a time-of-flight secondary ion mass spectrometer (e.g., ION- This can be done using TOF.SIMS5) manufactured by TOF Corporation. The optical film was cut into pieces measuring 10 mm x 10 mm and analyzed by a time-of-flight secondary ion mass spectrometer. The sample is placed in the sample chamber of the sample sintering device so that the primary ions are irradiated onto the surface of the functional layer. The surface of the functional layer is irradiated with light to measure ultraviolet absorption in the first region, the second region, and the third region. The intensity of the secondary ions originating from the absorbent is measured. Since it contains CN, the secondary ions derived from the UV absorber - Also, nitrogen atoms are detected. When the ultraviolet absorber containing the compound is a benzotriazole-based compound, the ultraviolet absorber-derived CN as secondary ion - or C6H4N3 - is detected.

[0196] Using the above TOF.SIMS5, the intensity of secondary ions originating from the UV absorber is measured. For example, the following measurement conditions can be used. In order to achieve this, an Ar gas cluster ion beam is used as the etching ion. By using gas cluster ion beams, it is possible to achieve low damage in organic structures. Etching is possible. Secondary ion polarity: negative ·Mass range (m / z): 0~3000 Raster size: 200μm Number of scans: 1 scan / cycle Number of pixels (per side): 128 pixels Measured vacuum level (before sample introduction): 4×10 -7 Pa or less Charge neutralization: Yes ·Late acceleration: 10kV Primary ion: Bi3 ++ Primary ion acceleration voltage: 30 kV 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): approx. 1400

[0197] In the functional layer 102, the most of the secondary ions derived from the ultraviolet absorbing agent in the first region 102C Small strength I U1(min) However, the maximum amount of secondary ions originating from the ultraviolet absorbing agent in the second region 102D is Small strength I U2(min) and the ultraviolet absorbing agent in the second region 102D is smaller than the ultraviolet absorbing agent in the second region 102D. Minimum secondary ion intensity I U2(min) However, the ultraviolet absorbing agent in the third region 102E Minimum secondary ion intensity I U3(min) It is preferable that the functional layer 1 is smaller than In the above-mentioned case, by having such a relationship, the surface 102A of the functional layer 102 is The ultraviolet absorbing agent gradually increases toward the surface 102B, so there is an extreme difference in the concentration of the ultraviolet absorbing agent. Therefore, it is possible to further suppress the occurrence of cracks in the functional layer 102 during a durability test. Cut.

[0198] In the functional layer 102, the secondary ions originating from the ultraviolet absorbing agent in the first region 102C maximum strength I U1(max) However, the secondary ions originating from the ultraviolet absorbing agent in the second region 102D Minimum Strength I U2(min) and the ultraviolet absorbing agent in the second region 102D is smaller than Maximum intensity of secondary ions I U2(max) However, the ultraviolet absorbing agent in the third region 102E Minimum intensity of secondary ions I U3(min) It is preferable that the thickness of the functional layer is smaller than 100 nm. In 102, by having such a relationship, from the surface 102A of the functional layer 102 The ultraviolet absorbing agent gradually increases toward the rear surface 102B, so there is an extreme difference in concentration of the ultraviolet absorbing agent. Therefore, the occurrence of cracks in the functional layer 102 during a durability test can be further suppressed. can.

[0199] In the functional layer 102, the secondary ions originating from the ultraviolet absorbing agent in the first region 102C Minimum Strength I U1(min) However, the light-transmitting substrate 11 in the first region 102C of the functional layer 102 The ultraviolet absorbing agent-derived ultraviolet absorbing agent in the fourth region 102F from the side boundary 102C1 to the back surface 102B Minimum intensity of secondary ions I U4(min) In the functional layer 102, In this case, by having such a relationship, in the functional layer 102, the first region 102C The UV absorber content is the lowest in the product, so there is no precipitation of the UV absorber, no reduction in surface hardness, and no wear resistance. The decrease in scratch resistance can be further suppressed.

[0200] The functional layer 102 may contain a fluorine atom-containing compound as described below. When the first region 102 contains a fluorine atom-containing compound, the first region 102 measured by TOF-SIMS Intensity of secondary ions originating from fluorine-containing compounds in 02C I F1 However, the second region 102 D and the secondary ions originating from the fluorine-containing compound in the third region 102E. Strength I F2 , I F3 That is, it is preferable that the fluorine atom-containing The compound is unevenly distributed on the surface 102A side (first region 102C) of the functional layer 102. Degree I F1 However, the above intensity I F2 , I F3 Since it is larger than the fluorine atom-containing Since the organic compound is abundant in the first region 102C of the functional layer 102, the ultraviolet absorbing agent is not absorbed on the surface 102A. It is possible to suppress precipitation.

[0201] Secondary inclusions derived from fluorine-containing compounds in the second region 102D and the third region 102E On Intensity I F2 , I F3 Fluorine-containing compound-derived in the first region 102C Secondary ion intensity I F1 The ratio (I F1 / I F2 , I F1 / I F3 ) are over 30 It is preferable that the above is the case. F1 / I F2 and I F1 / I F3 are over 30 each In this case, the ultraviolet absorbing agent can be further prevented from being deposited on the surface 102A. F1 / I F2 Oh Bi I F1 / I F3 The lower limits are 40 or more, 50 or more, 60 or more, or 70 or more, respectively. It is more preferable that there is.

[0202] The functional layer 102 may contain a silicon atom-containing compound as described below. When the silicon atom-containing compound is included in the first region 102, the silicon atom-containing compound is Intensity of secondary ions originating from silicon-containing compounds in 02C I S1 However, the second region 102 D and the secondary ions originating from the silicon atom-containing compound in the third region 102E. Strength I S2 , I S3 That is, it is preferable that the silicon atom-containing The compound is unevenly distributed on the surface 102A side (first region 102C) of the functional layer 102. Degree I S1 However, the above intensity I S2 , I S3 The silicon-containing Since the organic compound is abundant in the first region 102C of the functional layer 102, the ultraviolet absorbing agent is not absorbed on the surface 102A. It is possible to suppress precipitation.

[0203] Secondary indium ions derived from silicon-containing compounds in the second region 102D and the third region 102E On Intensity I S2 , I S3 Silicon-containing compound in the first region 102C Secondary ion intensity I S1 The ratio (I S1 / I S2 , I S1 / I S3 ) are 3 or more each It is preferable that S1 / I S2 and I S1 / I S3 If each is 3 or more, In this way, deposition of the ultraviolet absorbing agent on the surface 102A can be further suppressed. S1 / I S2 and I S1 / I S3More preferably, the lower limits of are 5 or more, 10 or more, or 15 or more, respectively. I wish.

[0204] Intensity of secondary ions from fluorine-containing compounds and silicon atoms by TOF-SIMS The intensity of the secondary ions originating from the fluorine-containing compound is the same as that of the secondary ions originating from the above-mentioned UV absorber. The measurement can be performed by the same method. F as secondary ions from fluorine-containing compounds - Also, silicon-containing compounds are detected. Since the compound contains silicon atoms, SiO2 is generated as a secondary ion derived from the silicon-containing compound. - is detected.

[0205] The indentation hardness of the functional layer 102 is 75 MPa or more and 1000 MPa or less. It is preferable that the indentation hardness of the functional layer 102 is 75 MPa or more. If the desired pencil hardness can be obtained and the hardness is 1000 MPa or less, the occurrence of cracks is suppressed. The lower limit of the indentation hardness of the functional layer 102 is 100 MPa or more, and 150 MPa or more, more preferably 200 MPa or more. The upper limit of the indentation hardness is 900 MPa or less, 750 MPa or less, or 600 The indentation hardness of the functional layer 102 is preferably 1.0 MPa or less. The measurement is carried out by the method described in the embodiment.

[0206] The functional layer 102 includes a resin and an ultraviolet absorbing agent including nitrogen atoms. In addition to resins and UV absorbers, fluorine-containing compounds, silicon-containing compounds, heavy A polymerization initiator may be included.

[0207] <Resin> The resin contained in the functional layer 102 is a polymerized product (cured product) of a polymerizable compound. Resins include polymerized compounds, solvent-drying resins, and thermosetting compounds. The polymerizable compound may be the same as the polymerizable compound described in the section for the second functional layer 13. The solvent drying type resin and the thermosetting compound have the first function. Since this is similar to the solvent drying type resin and thermosetting compound described in the section on layer 12, the description will not be given here. shall be omitted.

[0208] <Ultraviolet absorbing agent> The ultraviolet absorbing agent is the same as that described in the first embodiment, and therefore will not be described here. Explanation will be omitted.

[0209] <Fluorine atom-containing compounds> The fluorine atom-containing compound is not particularly limited as long as it contains a fluorine atom. Examples of fluorine-containing compounds include fluorine-based leveling agents. By using a silicon-based leveling agent, it has high leveling properties, making it smooth and easy to recoat. Commercially available fluorine-based leveling agents include F-555 (DIC Corporation) F-568 (manufactured by DIC Corporation), ... (manufactured by Neos Co., Ltd.)

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

[0211] The average particle size of the silica particles is preferably 1 nm or more and 1000 nm or less. If the average particle size of the particles is 1 nm or more, silica particles can be easily produced. If the thickness is less than 1000 nm, it is possible to provide the film with slipperiness while maintaining high transparency. The average particle size of the moss particles was measured using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STE 20 silica particles were extracted from cross-sectional images of silica particles taken at magnifications of 40,000 to 200,000 using a 3D scanner. The particle size of the moss particles is measured, and the arithmetic mean value of the particle sizes of 20 silica particles is calculated.

[0212] The functional layer 102 may be formed using one type of composition, but may also be formed using two or more types of compositions. When the functional layer 102 is formed using two or more compositions, In this case, for example, the first composition for the functional layer contains a polymerizable compound and an ultraviolet absorber containing a nitrogen atom. Alternatively, the functional layer may be formed using a second composition for the functional layer, which contains a polymerizable compound and a polymerizable compound.

[0213] <First composition for functional layer> The first composition for the functional layer contains the above-mentioned polymerizable compound and ultraviolet absorber, and other necessary ingredients. If necessary, it may contain a polymerization initiator, a solvent, a leveling agent, etc. The leveling agent is the same as the polymerization initiator, the solvent, and the leveling agent described in the first embodiment. Therefore, the description will be omitted here.

[0214] <Second composition for functional layer> The second composition for the functional layer contains the above-mentioned polymerizable compound and the like, and further contains the above-mentioned fluorine atom-containing compound. the silicon atom-containing compound, the solvent-drying resin, the thermosetting compound, and polymerization initiation. The second composition for the functional layer may contain, as necessary, the composition of the present invention. The following various additives may be included as long as they do not impair the effect. Examples of such additives include antistatic agents, adhesion improvers, thixotropy agents, coupling agents, plasticizers, Examples of the additives include antifoaming agents, fillers, colorants, etc.

[0215] The polymerization initiator in the second composition for the functional layer is the same as the polymerization initiator in the first composition for the functional layer. However, it is preferable that they are different. The polymerization initiator in the first composition for the functional layer is different from the polymerization initiator in the first composition for the functional layer. In the second composition for the functional layer, a polymerization initiator that is easy to semi-cure is selected. A polymerization initiator having good surface curing properties can be selected.

[0216] <<Optical film manufacturing method>> The optical film 100 can be produced, for example, as follows. As shown in FIG. 1(A), a functional layer is formed on one surface 101A of a light-transmitting substrate 101. The composition is applied and dried to form a first coating film 111. Next, as shown in FIG. As shown in the figure, the first coating film 111 is irradiated with ionizing radiation such as ultraviolet light to polymerize the polymerizable compound. By cross-linking (cross-linking), the first coating film 111 is semi-cured.

[0217] After the first coating film 111 is semi-cured, a second composition for a functional layer is applied to the surface of the first coating film 111. When the coating is dried, as shown in FIG. 12(A), in addition to the second coating film 112, the first coating film 1 A mixed coating containing the components of the first coating film 111 and the second coating film 112 is provided between the first coating film 111 and the second coating film 112. The mixed coating film 113 is formed. For reasons unknown, the mixed coating film 113 is formed of the second composition for the functional layer. When the solvent penetrates the semi-cured first coating film 111, the polymerizable compound component also becomes semi-cured. It is believed that the crystalline particles are drawn into the first coating film 111 in a cured state and are formed.

[0218] Next, as shown in FIG. 12(B), the first coating film 111, the second coating film 112 and the mixture are The coating film 113 is irradiated with ionizing radiation such as ultraviolet light to polymerize (crosslink) the polymerizable compound. The first coating film 111, the second coating film 112, and the mixed coating film 113 are cured (for example, completely cured) by Here, the first coating film 111, the second coating film 112, and the mixed coating film 113 are cured. As a result, the interfaces disappear and one 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 In the optical film 100 in which the layer 102 contains an ultraviolet absorbing agent containing nitrogen atoms, the first region 1 Intensity of secondary ions originating from ultraviolet absorbers in 02C I U1 In the second region 102D Intensity of secondary ions originating from ultraviolet absorbers in I U2 The ratio (I U2 / I U1 ) is 1.1 or more Since the value is 4.0 or less, the amount of the ultraviolet absorbing agent near the surface 102A of the functional layer 102 is small. In addition, the intensity I of the secondary ions originating from the ultraviolet absorbing agent in the second region 102D is U Intensity of secondary ions originating from the ultraviolet absorber in the third region 102E relative to 2 I U3 The ratio ( I U3 / I U2 ) is 1.2 or more and 4.0 or less, so the first region 1 It is possible to suppress the occurrence of an extreme difference in concentration of the ultraviolet absorbing agent in the third region 102C to the third region 102E. This can prevent cracks from occurring in the functional layer 102 during a durability test. The optical film has good surface hardness, good scratch resistance, and good durability while achieving the above. In this specification, the term "good surface hardness" means at least The term "hardness" also means a degree of surface hardness that prevents the optical film 100 from being scratched during processing. The term "scratch resistance" refers to a resistance to scratches that is at least not caused during processing of the optical film 100. It means scratch resistance.

[0220] <<<Polarizing plate and image display device>>> The optical film 100 is incorporated into a polarizing plate or an image display device in the same manner as the optical film 10. FIG. 13 is a schematic diagram of a polarizing plate according to this embodiment. 14 is a schematic diagram of an image display device according to this embodiment. The image display device 130 shown in FIG. 20 and FIG. 14 includes the optical film 100. 13 and 14, the same reference numerals as those in FIGS. 6 and 7 denote the same components as those in FIGS. 7, and therefore the description thereof will be omitted. EXAMPLES

[0221] In order to explain the present invention in detail, the following examples are given. The following is not intended to be limiting. In addition, unless otherwise specified, "parts" or "%" in the text Based on mass.

[0222] <<Example A and Comparative Example A>> <Example A1> (Preparation of Undercoat Layer Composition 1) Equip a 200 mL four-neck flask with a ball condenser, mercury thermometer, and stirring device. , 6-[5-(2-hydroxyethyl)-2H-benzotriazol-2-yl]benzo [1,3]dioxol-5-ol 4.0 g (0.013 mol), toluene 40 mL, 1.8 g (0.021 mol) of methacrylic acid, 0.4 g (0.004 mol) of methanesulfonic acid ) was added and the mixture was refluxed at 110-115°C for 4 hours for dehydration. Add 0.6 g (0.006 mol) of sodium hydroxide, leave to stand, separate and remove the lower aqueous layer, and 0.2 g of charcoal was added, and the mixture was refluxed and stirred to remove color. After filtration, toluene was extracted from the filtrate. 40 mL was collected by reducing the pressure, and 100 mL of isopropyl alcohol was added to the mixture. The crystals were filtered and washed with 40 mL of isopropyl alcohol. The resulting mixture was dried at 4.2° C. to obtain 4.2 g of yellow crystals. The 4.2 g of yellow crystals were dissolved in isopropyl alcohol. The mixture was repulped and washed with water and dried at 40°C under reduced pressure. As a zole compound, 3.4 g of 2-[2-(6-hydroxybenzo[1,3]dioxazole] (2H-benzotriazol-5-yl)ethyl methacrylate was obtained. Ta.

[0223] Next, a four-neck flask was equipped with a Dimroth condenser, a mercury thermometer, a nitrogen gas blowing tube, and a stirring The apparatus was set up and the synthesized 2-[2-(6-hydroxybenzo[1,3]dioxole- 16 parts by mass of 2H-benzotriazol-5-yl]ethyl methacrylate, 24 parts by mass of methyl methacrylate (MMA) as another monomer, toluene as a solvent 20 parts by mass of methyl ethyl ketone, and 1,1'-aryl ether as a polymerization initiator. Add 0.6 parts by mass of cyclohexane-1-carbonitrile and add nitrogen while stirring. After replacing the atmosphere in the flask with nitrogen at a gas flow rate of 10 mL / min for 1 hour, the reaction mixture temperature was kept at 90-96 °C. The polymerization reaction was carried out at 0.degree. C. for 10 hours under reflux.

[0224] After the polymerization reaction was completed, 10 parts by mass of toluene and 10 parts by mass of methyl ethyl ketone (MEK) were added. The acrylic polymer was prepared by adding a sesamol-type benzotriazole compound to MMA. 100.6 parts by mass of a solution containing Mer 1 (ultraviolet absorber 1) was obtained.

[0225] The above acrylic polymer 1 was dissolved in tricyclodecane dimethanol diacrylate (product name: A -DCP" manufactured by Shin-Nakamura Chemical Co., Ltd.) in a solids mass ratio of 60:40, and Synthetic initiators (Omnirad 184 from IGM Resins BV and BASF Di 4 parts by weight of IRGACURE (registered trademark) OXE01 (mass ratio 50:50) manufactured by Japan Co., Ltd. 0.2 parts by mass of a leveling agent (product name "F-568", manufactured by DIC Corporation) was added. The mixture was thoroughly stirred to prepare a composition 1 for undercoat layer.

[0226] (Preparation of hard coat layer composition 1) The above acrylic polymer 1 was mixed with dipentaerythritol hexaacrylate and dipentaerythritol hexaacrylate. Mixture of thritol pentaacrylate (product name: KAYARAD DPHA, Nippon Kayaku Co., Ltd.) The solids were mixed with 1,000g of ethyl alcohol (manufactured by IGM Res Pharmaceutical Co., Ltd.) in a solids mass ratio of 45:55, and a polymerization initiator (IGM Res Omnirad184 manufactured by ins BV and ESACU manufactured by DKSH Japan RE ONE (mass ratio 50:50) 4 mass parts and leveling agent (product name "F-568", 0.2 parts by mass of 1,2-dichlorophenyl ether (manufactured by DIC Corporation) was added and thoroughly stirred to obtain a hard coat layer composition 1. was prepared.

[0227] (Preparation of Optical Films) The obtained undercoat layer composition 1 was applied to a plate measuring 210 mm x 297 mm (A4 size) using a Meyer bar. The cycloolefin polymer substrate (product name "ZEONOAFFILI") with a thickness of 50 μm was used. The first layer was coated with a 100% cellulose ester (registered trademark ZF14-050, manufactured by Zeon Corporation) A coating film was formed. Next, the first coating film was dried at 50°C with a flow rate of 0.5 m / s. Dry air is passed through for 30 seconds to evaporate the solvent in the first coating, and then ultraviolet light is applied for a total of is 120mJ / cm 2 The first coating film was semi-cured by irradiating it so as to achieve a temperature of 100° C.

[0228] After forming the semi-cured first coating, the hard coat layer is applied to the surface of the first coating with a Maya bar. Composition 1 was applied to form a second coating film. Dry air at 70°C was passed through the second coating at a flow rate of 1.5 m / s for 30 seconds to evaporate the solvent in the second coating. The ultraviolet light is emitted at an integrated dose of 200 mJ / cm 2 The first coating film and the second coating film are cured by irradiating the first coating film with light so that the first functional layer is formed. The thickness of the underlayer is 1 μm, the thickness of the mixed layer is 0.4 μm, and the thickness of the second functional layer is As a result, a hard coat layer of 3 μm was formed on the cycloolefin polymer substrate. Thus, an optical film having an undercoat layer, a mixed layer, and a hard coat layer in this order was obtained.

[0229] The thickness of the underlayer was measured by photographing the cross section of the underlayer using a scanning transmission electron microscope (STEM). The thickness of the underlayer was measured at 10 points on the cross-sectional image, and the arithmetic average of the thicknesses at those 10 points was calculated. The specific method for taking cross-sectional photographs was as follows. First, a 1 mm x 10 mm The optical film cut out into pieces was embedded in an embedding resin to prepare a block, and the block was By using the general sectioning method, a uniform thickness of about 70 nm to 300 nm without holes can be obtained. Sections were cut. The sections were prepared using an ultramicrotome EM UC7 (Leica The uniform section without holes was used as the measurement sample. Then, a scanning transmission electron microscope (STEM) (product name "S-4800", A cross-sectional photograph of the measurement sample was taken using a microscope (Hitachi High-Technologies Corporation). When taking cross-sectional photographs using the S-4800, the detector should be set to "TE" and the accelerating voltage to "3 The cross-sectional observation was performed with the voltage at "0 kV" and the emission current at "10 μA". Adjust the focus and observe the contrast and brightness to see if each layer can be distinguished. The magnification was adjusted appropriately within the range of 10,000 to 100,000 times depending on the thickness of the layer. The thickness was changed to "5.0" and the WD to "8.9 mm". The thickness of the undercoat layer was also measured in the same manner as the thickness of the undercoat layer. In Example 6 and Comparative Examples A1 to A6, the undercoat layer and the mixed layer were formed in the same manner as in Example A1. The thickness of the hard coat layer was then measured.

[0230] <Example A2> In Example A2, the integrated light amount was 20 0mJ / cm 2 The first coating is semi-cured by irradiating it with ultraviolet light so that the thickness of the first coating is The optical film was prepared in the same manner as in Example A1, except that a mixed layer having a thickness of 0.04 μm was formed. Got it.

[0231] <Example A3> In Example A3, the integrated light amount was 200 mJ / cm 2 The first coating is then exposed to ultraviolet light. The first coating was semi-cured by irradiating the coating with light to form 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 undercoat layer was 1.2 μm, and the integrated light amount was 70 mJ / cm 2 The first coating is semi-cured by irradiating it with ultraviolet light so that the thickness of the mixed layer becomes The thickness of the hard coat layer was set to 3.1 μm, and the thickness of the hard coat layer was set to 1 μm. 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 / cm 2 The first coating The first coating was semi-cured by irradiating the first coating with light to a thickness of 0.5 μm. An optical film was obtained in the same manner as in Example A1, except that the thickness of the coated layer was 8 μm. Ta.

[0234] <Example A6> In Example A6, the integrated amount of ultraviolet light was 70 mJ / cm 2 The first coating is The first coating was semi-cured by irradiation to make the mixed layer 1 μm thick. An optical film was obtained in the same manner as in Example A1, except that the thickness of the acrylic layer was 0.5 μm. .

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

[0236] (Preparation of hard coat layer composition 2) The above acrylic polymer 1 is mixed with urethane acrylate (product name "Beamset 577", The solids were mixed with a polymerization initiator (IGM Mass of Omnirad184 and Omnirad819 manufactured by Resins BV Ratio 50:50) and 4 parts by mass of leveling agent (product name "F-568", manufactured by DIC Corporation) 0.2 parts by mass of the above was added and thoroughly stirred to prepare a composition 2 for hard coat layer.

[0237] <Example A8> In Example A8, the undercoat layer composition 2 was used instead of the undercoat layer composition 1, and Instead of hard coat layer composition 1, hard coat layer composition 2 was used to form a film with a thickness of 0. An optical film was obtained in the same manner as in Example A2, except that a mixed layer with a thickness of 0.04 μm was formed.

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

[0239] <Example A10> In Example A10, the undercoat layer composition 3 was used instead of the undercoat layer composition 1. Except for the above, an optical film was obtained in the same manner as in Example A1. It was prepared as follows. (Preparation of Undercoat Layer Composition 3) Indole-based compound (product name: BONASORB UA-3912, Orient Chemical (UV absorber 2) was added to dicyclopentenyl acrylate (product name "FA -511AS" manufactured by Hitachi Chemical Co., Ltd.) in a solid content mass ratio of 10:90, and polymerized Initiators (Omnirad184 and Omnira from IGM Resins BV) d819 (mass ratio 50:50) 4 parts by mass and a leveling agent (product name "F-568", DI C Corporation) and 0.2 parts by mass of the above-mentioned solvent were added thereto and thoroughly stirred to prepare a composition 3 for undercoat layer.

[0240] <Example A11> In Example A11, the undercoat layer composition 4 was used instead of the undercoat layer composition 1. Except for the above, an optical film was obtained in the same manner as in Example A1. It was prepared as follows. (Preparation of Undercoat Layer Composition 4) Hydroxyphenyltriazine ultraviolet absorber (product name: Tinuvin 479, B ASF) (UV absorber 3) was added to dicyclopentenyl acrylate (product name "FA-5 11AS" (Hitachi Chemical Co., Ltd.) in a solids mass ratio of 30:70, and polymerization was initiated. Resins (Omnirad184 and Omnirad8 from IGM Resins BV) 19 (mass ratio 50:50) and a leveling agent (product name "F-568", DIC Corporation The mixture was thoroughly stirred to prepare a composition 4 for undercoat layer.

[0241] <Example A12> In Example A12, a cycloolefin polymer-based substrate having a thickness of 50 μm (product name " Zeonoa Film (registered trademark) ZF14-050 (manufactured by Zeon Corporation) A cycloolefin polymer substrate with a thickness of 50 μm (product name: ZEONOR FILM (registered trademark) The in-plane retardation was set to 100 nm. A cycloolefin polymer with a thickness of 25 μm was prepared 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 the cycloolefin polymer-based substrate, a 60 μm thick Triacetyl cellulose substrate (product name: Fujitac TD60UL, Fujifilm Corporation) An optical film was obtained in the same manner as in Example A1, except that a polyimide film (manufactured by Co., Ltd.) was used.

[0243] <Example A14> In Example A14, instead of the cycloolefin polymer-based substrate, a 25 μm thick Triacetyl cellulose substrate (product name: Fujitac TJ25UL, Fujifilm Corporation) An optical film was obtained in the same manner as in Example A1, except that a polyimide film (manufactured by Co., Ltd.) was used.

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

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

[0246] <Comparative Example A1> The composition for the undercoat layer 1 was applied to a plate measuring 210 mm x 297 mm (A4 size) using a Meyer bar. and a cycloolefin polymer-based substrate with a thickness of 50 μm (product name: Zeonor Film (registered trademark) (registered trademark) ZF14-050 (manufactured by Zeon Corporation) on the surface to form a coating film. Next, the formed coating was irradiated with dry air at 50°C for 30 seconds at a flow rate of 0.5 m / s. By circulating the water, the solvent in the first coating is evaporated, and the ultraviolet rays are irradiated in a nitrogen atmosphere (oxygen concentration 20 0ppm or less) with an integrated light intensity of 400mJ / cm 2 The first coating was completely As a result, a base layer having a thickness of 1 μm was formed.

[0247] After forming a completely cured first coating, a hard coat layer is applied to the surface of the first coating using a Mayer bar. Composition 1 was applied to form a second coating film. Dry air at 70°C was passed through the coating at a flow rate of 1 / s for 30 seconds to evaporate the solvent in the coating. , ultraviolet light is irradiated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) with an integrated light intensity of 200 mJ / cm 2 The coating is then cured by irradiating it at a temperature of 150° C. to form a hard coat layer with a thickness of 3 μm. As a result, a base layer and a hard coat layer were formed on the cycloolefin polymer substrate. In addition, 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 undercoat layer was set to 1.2 μm, and ultraviolet rays were irradiated in a nitrogen atmosphere ( At oxygen concentration of 200 ppm or less, the cumulative light intensity is 300 mJ / cm 2 The first coating is The first coating was semi-cured by irradiation, and the thickness of the mixed layer was set to 0.01 μm. 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 undercoat layer was set to 1.2 μm, and ultraviolet rays were irradiated in a nitrogen atmosphere ( At oxygen concentration of 200 ppm or less, the cumulative light intensity is 200 mJ / cm 2 The first coating is The first coating was semi-cured by irradiation to make the mixed layer 0.05 μm thick. An optical film was obtained in the same manner as in Example A1, except that the thickness of the coated layer was 8 μm. Ta.

[0250] <Comparative example A4> In Comparative Example A4, the integrated amount of ultraviolet light was 50 mJ / cm 2 The first coating is The first coating was semi-cured by irradiation to make the mixed layer 2.0 μm thick. An optical film was prepared in the same manner as in Example A1, except that the thickness of the coating layer was 1.0 μm. Got it.

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

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

[0253] <Maximum absorption wavelength and absorbance at wavelengths of 380 nm to 500 nm> Maximum absorption wavelength λ of UV absorber 1 (acrylic polymer 1) max and wavelength 380 nm The absorbance at ~500 nm was measured using a spectrophotometer (product name: UV-2450, Shimadzu Corporation). Measurements were performed using a tungsten lamp and a deuterium lamp (Light source: Tungsten lamp and Deuterium lamp) Maximum absorption wavelength λ max The absorbance was measured by reducing the solution containing the obtained UV absorber 1. After removing the solvent by drying under reduced pressure, the sample was dissolved in chloroform at a concentration of 40 ppm. The maximum absorption wavelength λmax and absorbance of ultraviolet absorbers 2 and 3 are measured by using ultraviolet absorbers 2 and 3. The test was carried out in a chloroform solution with a concentration of 40 ppm. The results were as follows: [Table 1]

[0254] <Adhesion> A durability test was performed on the optical films according to Examples A1 to A16 and Comparative Examples A1 to A6. The adhesion was evaluated before and after the durability test. The optical film was cut into pieces and placed in a durability test device (product name: "Constant Temperature and Humidity Chamber PL-1KP" (manufactured by Peck Co., Ltd.) and left for 240 hours under conditions of 85°C temperature and 85% relative humidity. The optical film had no defects (contamination of foreign matter) and no cracks. The test pieces are free of wrinkles, dirt, and curls, and are placed in a flat, durable test device. was placed inside.

[0255] The adhesion was evaluated before and after the durability test under conditions of 23°C temperature and 50% relative humidity. Specifically, first, the optical films according to Examples A1 to A16 and Comparative Examples A1 to A5 Using a cutter knife, cut 10 squares x 10 squares at 1 mm intervals in mutually orthogonal directions. The cuts were made in a grid pattern. The cuts penetrated the hard coat layer and the undercoat layer. The grid was formed and hardened. Apply adhesive tape (model number "No. 405, Nichiban Co., Ltd., 24 mm wide) was attached to one end of the attached adhesive tape. Grasp the hard coat layer and hold it in a direction almost perpendicular to the surface of the hard coat layer, then peel it off instantly to check the adhesion. The evaluation criteria were as follows. The number of remaining pieces was 100, that is, In other words, if there was no peeling, it is recorded as 100 / 100, and if all of them fell off, it is recorded as 0 / It is written as 100. A:100 / 100 B:99 / 100~50 / 100 C:0 / 100~49 / 100

[0256] <Pencil hardness> The surfaces (hard coat layers) of the optical films according to Examples A1 to A16 and Comparative Examples A to A6 The pencil hardness of each surface was measured. A sample of 50 mm x 100 mm was cut from the film and placed on a glass plate. To prevent wrinkles, fix the paper with Nichiban Co., Ltd.'s Scotch tape (registered trademark) and apply pencil-hardened tape. Hardness tester (product name: Pencil scratch coating hardness tester (electric type), Toyo Seiki Seisakusho Co., Ltd. The pencil (product name: Uni) was used in an environment with a temperature of 23°C and a relative humidity of 50% or less. A 300g load was applied to a pencil (manufactured by Mitsubishi Pencil Co., Ltd.) and the pencil was moved at a speed of 3mm / sec. The pencil hardness was determined by the highest hardness that did not scratch the surface of the sample in the pencil hardness test. When measuring pencil hardness, several pencils with different hardness are used. The pencil hardness test was carried out five times for each brush, and the surface of the sample was examined under fluorescent light at least four times out of the five times. If no scratches were visible on the surface of the sample when observed through a pencil of this hardness, In this case, it is judged that the surface of the sample was not scratched.

[0257] <Visibility evaluation> Visibility evaluation using the optical films according to Examples A1 to A16 and Comparative Examples A1 to A6 Specifically, the OLED display device (product name "Galaxy SII", Samsung An optical film cut to a size of 50 mm x 50 mm was placed on a 50 mm thick plate (manufactured by ung Co., Ltd.). The LED was turned on in the dark and in the bright place (OLED display ambient illuminance 400 lux). The displayed images were observed through optical sunglasses, and the presence or absence of rainbow unevenness was evaluated according to the following criteria. The observations were conducted by 10 people, and the most common evaluation was recorded as the observation result. A: No rainbow irregularities were observed through polarized sunglasses, and visibility was good. B: Although some rainbow irregularities were observed through polarized sunglasses, visibility was good. C: Strong rainbow irregularities were observed through polarized sunglasses, and visibility was poor.

[0258] <Spectral transmittance> In the optical films according to Examples A1 to A11, A13, and A15, the temperature was 23° C. At 50% relative humidity, wavelengths of 380 nm, 400 nm, 410 nm, and 440 nm The spectral transmittance at 1000 nm was measured. The optical film was measured using a spectrophotometer (product name: UV- 2450, Shimadzu Corporation, light source: tungsten lamp and deuterium lamp) The optical film was placed so that the substrate side of the optical film faced the light source side. It is free of blemishes, cracks, wrinkles, stains, and curls. The sample was held in the spectrophotometer in a flat, undisturbed state. In this state, the following measurement conditions were used: The maximum value is within 1 nm at 400 nm, 410 nm, and 440 nm. The transmittance at five low points is measured and the average value is calculated. The spectral transmittance was measured at 400 nm, 410 nm, and 440 nm. The spectral transmittance at 400 nm, 410 nm, and 440 nm was measured in triplicate. The arithmetic mean of the values ​​obtained was used. (Measurement conditions) ·Wavelength range: 300nm~780nm Scan speed: Fast Slit width: 2.0 Sampling interval: Auto (0.5 nm interval) ·Lighting:C Light source: D2 and WI ·Field of view: 2° Light source switching wavelength: 360nm S / R Switching: Standard Detector: PM Autozero: Performed at 550 nm after baseline scan

[0259] <Yellow Index (YI)> The yellow index of the optical films according to Examples A1 to A11, A13, and A15 was measured. Specifically, the optical film was cut into a size of 50 mm x 50 mm. The temperature was 23°C and the relative humidity was 50%. Shimadzu Corporation, light source: tungsten lamp and deuterium lamp) with optical filter The optical film was placed so that the substrate side of the film faced the light source side. , crack-free, wrinkle-free, stain-free, and flat without curls. The sample was held in a spectrophotometer. In this state, the transmittance at wavelengths of 300 nm to 780 nm was measured. Then, on the PC connected to the UV-2450, read the transmittance measurement data, YI was obtained by checking "YI" in the calculation item. Wavelength 300nm~7 The measurement conditions for the transmittance at 80 nm are the same as the measurement conditions for the spectral transmittance at the wavelength of 380 nm, etc. The same was true.

[0260] <Total light transmittance measurement> In the optical films according to Examples A1 to A11, A13, and A15, the haze meter ( Using the product name "HM-150" manufactured by Murakami Color Research Laboratory, the temperature was 23°C and the relative humidity was The total light transmittance was measured in accordance with JIS K7361:1997 under an environment of 50% humidity. The light transmittance was measured by cutting the optical film into a size of 50 mm x 50 mm, and then removing any curls or wrinkles. The optical filter is placed so that the light-transmitting substrate faces the light source in a state where there is no dirt, fingerprints, dust, etc., and the optical filter is Each film was measured three times and the arithmetic mean value was calculated.

[0261] <Haze measurement> In the optical films according to Examples A1 to A11, A13, and A15, the haze meter ( Using the product name "HM-150" manufactured by Murakami Color Research Laboratory, the temperature was 23°C and the relative humidity was Measure the haze value (total haze value) according to JIS K7136:2000 under a 50% humidity environment. The haze value was measured by cutting the optical film into a size of 50 mm x 50 mm and then The light-transmitting substrate is placed on the light source side in a state where there are no marks or wrinkles, no fingerprints, no dust, etc. The measurement was carried out three times for each optical film, and the arithmetic average value was calculated.

[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, The optical film cut into pieces is then measured with a spectrophotometer (product Name: "UV-2450", manufactured by Shimadzu Corporation, light source: tungsten lamp and deuterium The optical film was placed in the lamp so that the substrate side of the optical film faced the light source. The film is free of defects (contamination of foreign matter), cracks, wrinkles, and dirt. The film was also held in the spectrophotometer in a flat, curl-free state. Under the same conditions as the measurement, within 1 nm at wavelengths of 300 nm to 780 nm The transmittance was measured for at least 5 points. The blue cut rate was calculated from the above formula (1). The blue light blocking rate was calculated by arithmetic average of three measurements.

[0263] <Light resistance test> The optical films according to Examples A1 to A11, A13, and A15 were adhered to an OLED display device. A light resistance test is conducted with the film attached through a layer, and the brightness is measured before and after the light resistance test. First, we checked whether the OLED display had deteriorated. The optical film is cut into pieces of 1.5 mm in size and placed on an adhesive layer (product name: Panaclean (registered trademark) P D-S1" manufactured by PANAC Corporation) through an OLED display device (product name "Galaxy The optical film was attached to a hard coat layer ("SII" manufactured by Samsung). The film was attached so that it was closer to the viewer than the light-transmitting substrate. The image display device is formed by laminating an OLED display device, an adhesive layer, and an optical film in this order. obtained.

[0264] The OLED display device was then turned on to measure the luminance before the light resistance test. The brightness of the light emitted from the surface of the image display device (the surface of the optical film) is calculated based on the thickness of the image display device. A spectroradiometer (product name "CS2000", manufactured by Konica Minolta, Inc.) was used from the The measurement was then performed at a measurement angle of 1°. The test was performed in an environment of 42°C and 50% relative humidity using a "U48AU" meter (manufactured by Suga Test Instruments Co., Ltd.). A light resistance test was conducted in which the image display device was irradiated with light from a carbon arc lamp under a 50-hour Then, the image display device after the light resistance test was turned on to measure the image quality of the image display device before the light resistance test. The luminance was measured under the same conditions as the luminance measurement. Using a "wire fade meter U48AU" manufactured by Suga Test Instruments Co., Ltd., the temperature was 42°C and the relative humidity was 5 Light resistance test in which a display device is exposed to light from a carbon arc lamp for 100 hours at 0% humidity. The light resistance test was performed, and the image display device after the light resistance test was turned on to measure the image display device before the light resistance test. The luminance was measured under the same conditions as in the luminance measurement of 1.

[0265] From these measured luminance values, the luminance retention rate after the light fastness test relative to the luminance before the light fastness test was calculated. The luminance maintenance rate was calculated by taking the luminance maintenance rate (%) as D and the light resistance test The luminance of the surface of the image display device before the test is E, and the luminance of the image display device after the light resistance test when turned on is E. The surface brightness was defined as F and was calculated using the following formula. D=F / E×100

[0266] The obtained luminance maintenance rate can be used to determine whether the OLED display has deteriorated during the light resistance test. Specifically, if the luminance maintenance rate is less than 60%, the OLED display If the brightness maintenance rate is 60% or more, the OLED display device is deemed to have deteriorated. The evaluation criteria were as follows: A: No degradation of the OLED display was observed. B: Degradation of the OLED display was observed.

[0267] <Indentation hardness (H IT )> In the optical films according to Examples A1 to A11, A13, and A15, the ultraviolet absorbent was included. The indentation hardness of the layer was measured. In 15, the indentation hardness of the hard coat layer containing the ultraviolet absorber 1 is measured. Indentation hardness (H IT ) is manufactured by HYSITRON The measurements were taken using a TI950 TriboIndenter. The optical film was cut into a size of 10 mm and embedded in resin to create a block. A measurement sample suitable for hardness measurement by the non-indentation method was prepared. The preparation of the plates was performed using an ultramicrotome EM UC7 (Leica Microsystems, Inc.). Next, the surface of the sample to be measured that was to be pressed into the indenter was made flat with the surface on which the sample was placed on the stage. The measurement samples were placed on a HYSITRON TI950 T The sample was fixed on the stage of the riboIndenter. Then, a hard cover containing an ultraviolet absorber was placed on the sample. The maximum indentation load was 300 μN on the flat part at the center of the cross section of the support layer using the load control method. To obtain the specimen, a Berkovich-type indenter was applied at a loading rate of 10 μN / s, and the load was changed from 0 μN to 30 μN in 30 seconds. The layer containing the ultraviolet absorber was pressed into the center of the cross section while applying a load up to 0 μN, and then the After holding at 0 μN for 5 seconds, the load was removed from 300 μN to 0 μN in 30 seconds. The indentation depth h (nm) corresponding to the indentation load F (N) at the time of the load is continuously measured. The indentation hardness H was calculated from the load-displacement curve. IT of , the maximum pressing load F max (N) containing an indenter and a UV absorber Projected area A of the layers in contact p (mm 2 The indentation hardness was calculated by dividing the value by The thickness was the arithmetic average of the values ​​measured at 10 points. p is calculated by the above formula (3). This was the value that was obtained.

[0268] <Scratch resistance test> The surfaces of the optical films according to Examples A1 to A11, A13, and A15 were subjected to a scratch resistance test. Specifically, the back of the optical film was cut to a size of 50 mm x 50 mm. The surface was covered with a 50 μm thick transparent adhesive layer (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 plate (product name "Comoglass DFA502K", manufactured by Kuraray Co., Ltd.) Then, the surface of the optical film was smeared with #0000 steel wool (manufactured by Product name: Bonstar, manufactured by Nippon Steel Wool Co., Ltd.) was used at 100g / cm 2 Load The scratch resistance test was carried out by rubbing the optical film back and forth 10 times while applying pressure, and no scratches were found on the surface of the optical film. The evaluation results were as follows: A: No injuries were found. B: A few scratches were observed, but were not of a level that would cause any practical problems. C: The damage was clearly visible.

[0269] <Flexibility evaluation> (1) Evaluation of cracks and breakage after folding test The optical films according to Examples A1 and A12 to A16 were subjected to a folding test. Specifically, a 125 mm x 50 mm long piece was first cut from the optical film. A rectangular sample was cut out. After cutting out the sample, it was used as a folding durability tester. A U-shaped stretch tester (product name "DLDMLH-FS", manufactured by Yuasa System Co., Ltd.) Then, the short sides (50 mm) of the sample were fixed to the fixing parts, as shown in Figure 2(C). The minimum distance between the two opposing sides is 6 mm (the outer diameter of the bent part is 6 mm). The hard coat layer side of this sample was folded 180° under the following conditions. The test (folding test with the hard coat layer on the inside and the base material on the outside) was performed 100,000 times. I did. (Folding conditions) Reciprocating speed: 80 rpm (revolutions per minute) Test stroke: 60mm Bending angle: 180°

[0270] The bent portion was then inspected for cracks or breaks. The evaluation criteria were as follows: In addition, when the area to be the bent portion of each optical film was observed before the folding test, No cracks or breaks were observed. The evaluation criteria were as follows: (Foldability) A: Even after the folding test, no cracks or breaks were observed at the bent portion. B: After the folding test, some cracks were observed at the bent part, but this did not affect practical use. It was at that level. C: After the folding test, cracks or breaks were observed at the bent portion.

[0271] Similarly, the same samples as above were obtained from the optical films according to Examples A1 and A12 to A16. A sample was prepared by fixing each of the short sides of the sample with a fixing part, and the minimum length of the two opposing sides was The distance between the hard coat layer and the hard coat layer is 6 mm (the outer diameter of the bent part is 6 mm). A folding test was conducted in which the sample was folded 180 degrees 200,000 times so that the inner side was Similarly, the samples after the folding test were observed for cracks or breakage and evaluated according to the above criteria. Furthermore, samples similar to those described above were prepared from the optical films according to Examples A1, A12 to A16. The short sides of the sample were fixed with the fixing parts, and the minimum distance φ between the two opposing sides was The sample was then attached so that the thickness was 4 mm, and the hard coat layer was placed on the inside. A folding test was conducted in which the product was folded 180 degrees repeatedly 10,000 times. In the same manner, the size after the folding test was measured. The samples were observed for cracks and breakage and evaluated according to the above criteria.

[0272] (2) Evaluation of folds after folding test The appearance of the optical films according to Examples A1 and A12 to A16 after the folding test was observed. The folding test was carried out by observing whether or not a crease was formed at the bent portion of the optical film. Method described in the section on crack and fracture evaluation after folding test ((1) Minimum spacing φ: 6 mm ,Number of folds: 100,000 times, (2) Minimum spacing φ: 6 mm, Number of folds: 200,000 times, (3 The same method was used as for the minimum interval φ: 4 mm, number of folds: 200,000. The observation of creases was carried out visually in an environment with a temperature of 23°C and a relative humidity of 50%. When performing the test, the bending part is illuminated in a bright room with white lighting (800 lux to 2000 lux) using transmitted light and The reflected light was used to observe the entire surface, and the inside of the bent part was observed when folded. The part that was the inside and the part that was the outside were both observed. The sample before the folding test was placed on the fixed part of the U-shaped stretch tester so that the folding speed could be easily understood. When the sheet is folded once, as shown in FIG. 3, the sheet is folded perpendicular to the folding direction at the bent portion. Marks were made with an oil-based pen on both ends of the specimen to indicate that they were bent. After the folding test, the bending part was removed from the U-shaped stretch tester. A line was drawn with an oil-based pen connecting the marks on both ends. The bent portion is an area formed by the marks at both ends of the bent portion and the lines connecting the marks. The entire film was visually observed. Note that the area of ​​the bent portion of each optical film before the folding test was 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 pose a problem in practical use. It was at an unproblematic level. C: After the folding test, creases were observed in the optical film.

[0273] (3) Evaluation of microcracks after folding test The appearance of the optical films according to Examples A1 and A12 to A16 after the folding test was observed. The bending of the optical film was observed to evaluate whether microcracks had occurred. The test was performed according to the method described in the section on crack and fracture evaluation after the folding test above (minimum interval φ: 6 The observation of microcracks was carried out in the same manner as in the previous study (100 mm, 100,000 folding times). The observation was performed using a digital microscope (product name: The experiment was carried out using a 3D printer (VHX-5000, manufactured by Keyence Corporation). After the folding test, slowly unfold the sample and tape it to the microscope stage. If the folding is severe, fix the folding rod so that the observation area is as flat as possible. However, do not touch the part to be observed (bent part) near the center of the sample with your hands and do not apply force to it. Next, observe both the inside and outside parts of the folded paper. The observation of microcracks was performed using a ring light as the illumination for the digital microscope. The observation of microcracks was performed at a magnification of 200x under dark field and reflected light. In order to easily grasp the position to be observed, the sample before the folding test was folded in a U-shape. When the test piece was placed on the fixed part of the test machine and folded once, the bending part was Mark the bends with a permanent marker on both ends located perpendicular to the folding direction. After the folding test, the sample was removed from the U-shaped stretch tester. In this state, a line was drawn with an oil-based pen connecting the marks on both ends of the bent portion. In observing microcracks, the center of the microscope field of view is the center of the bend. The microscope was positioned so that the optical When the film was inspected in the area that would become the bend, no microcracks were observed. 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, This was at a level that would not pose a problem 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 according to Comparative Examples A1, A2, and A5 had poor durability. Even before the test, peeling occurred at the interface between the undercoat layer and the hard coat layer, so the adhesion before the durability test In the optical film according to Comparative Example A3, the initial adhesion was poor. The adhesion was good, but the adhesion after the durability test was poor. The optical film has poor pencil hardness, and the optical film according to Comparative Example A6 In contrast, the optical films according to Examples A1 to A16 were inferior in visibility evaluation. In the case of the adhesive layer, the adhesion before the durability test (initial adhesion) was good. This is a mixture containing the components of the underlayer and the hard coat layer between the underlayer and the hard coat layer. The thickness of the hard coat layer is 100 μm. This is believed to be because the ratio of the thickness of the mixed layer was 0.6% or more. In the optical films according to 1, A3 to A7, and A9 to A16, not only before the durability test, The adhesion after the durability test was also good. This is because the combination of the undercoat layer, the mixed layer, and the 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. The optical films according to Examples A1 to A16 were excellent in pencil hardness. This is because The ratio of the thickness of the mixed layer to the total thickness of the undercoat layer, the mixed layer and the hard coat layer is 40%. It is considered that this is because the optical films according to Examples A1 to A16 were This is because the light-transmitting substrate is made of cycloolefin polymer. Because the base material used was polymer-based, triacetyl cellulose, or acrylic resin It is believed to be the case.

[0279] <<Example B and Comparative Example B>> <Example B1> (Preparation of hard coat layer composition 3) 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 solid content mass ratio of 20:80 and add Dilute with solvent (methyl ethyl ketone and toluene in a mass ratio of 80:20) to 25% A resin composition was prepared by the above procedure. Next, 160 parts by mass of the obtained resin composition was subjected to polymerization initiation. Resins (Omnirad184 and Omnirad8 from IGM Resins BV) 19 (mass ratio 50:50) and 4 parts by mass of a leveling agent (product name "F568", DIC Corporation (manufactured by Company) and 0.2 parts by mass of 1,000g ... did.

[0280] (Preparation of hard coat layer composition 4) Urethane acrylate resin (product name: Beamset 577, Arakawa Chemical Industries, Ltd.) (manufactured by Epson) to 50% solids with solvents (methyl ethyl ketone and methyl isobutyl ketone, The resin composition was prepared by diluting the resin composition 20 in a ratio of 50:50. 0 parts by mass of polymerization initiator (Omnirad18 manufactured by IGM Resins BV) 4) 4 parts by weight and 0.2 parts by weight of leveling agent (product name "F568", manufactured by DIC Corporation) and silica nanoparticles (product name "SIRMIBK-E65", manufactured by CIK Nanotech Co., Ltd. ) were mixed together and thoroughly stirred to prepare a hard coat layer composition 4. .

[0281] (Preparation of Optical Films) The composition 3 for hard coat layer was measured with a Meyer bar to measure 210 mm×297 mm (A 4 sizes) and a 25μm-thick triacetyl cellulose-based substrate (product name "FUJITAC The first coating was formed on the surface of a 100% polyester film (TJ25UL, manufactured by Fujifilm Corporation). Then, dry air at 50°C was passed through 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 is evaporated, and the integrated amount of ultraviolet light is 120 mJ / cm 2 To The first coating film was semi-cured by irradiating it so as to obtain a cured film.

[0282] After forming the semi-cured first coating, the hard coat layer is applied to the surface of the first coating with a Maya bar. Composition 4 was applied to form a second coating film. The solvent in the coating was evaporated by passing dry air at 70°C for 30 seconds at a flow rate of 1.5 m / s. The ultraviolet light was emitted in a nitrogen atmosphere (oxygen concentration 200 ppm or less) with an integrated light intensity of 200 mJ / cm 2 The first and second coatings are cured by irradiating the film so that the cured film thickness is A 6μm thick hard coat consisting of a 3μm thick first coat and a 3μm thick cured second coat. As a result, a hard coat layer was formed on the triacetyl cellulose-based substrate. Thus, an optical film was obtained.

[0283] The thickness of the hard coat layer was determined in the same manner as for the thickness of the undercoat layer described in the column of Example A1. In addition, in Examples B2 to B11 and Comparative Examples B1 to B6, The thickness of the hard coat layer was measured in the same manner as in Example B1.

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

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

[0286] <Example B3> In Example B3, instead of a 6 μm thick hard coat layer, a 1 μm thick cured A hard coat layer with a thickness of 2 μm is formed by the first coating and the hardened second coating with a thickness of 1 μm. Except for the above, the same procedure as in Example B1 was carried out to obtain an optical film.

[0287] <Example B4> In Example B4, instead of a 6 μm thick hard coat layer, a cured 5 μm thick The hard coat layer was formed with a thickness of 10 μm, consisting of the first coating and the hardened second coating with a thickness of 5 μm. An optical film was obtained in the same manner as in Example B1, except that the above-mentioned step was carried out.

[0288] <Example B5> In Example B5, a triacetyl cellulose-based substrate having a thickness of 25 μm (product name "Fuji Instead of "Tac TJ25UL" (manufactured by Fujifilm Corporation), a 60 μm-thick triacetate Chilled cellulose substrate (product name: Fujitac TD60UL, manufactured by Fujifilm Corporation) An optical film was obtained in the same manner as in Example B1, except that the above-mentioned resin was used.

[0289] <Example B6> In Example B6, a 50 μm thick sheet was used instead of a triacetyl cellulose-based substrate. Chloroolefin polymer-based substrate (product name: ZEONORFILM (registered trademark) ZF14-05 0" manufactured by Zeon Corporation) was stretched at 150°C so that the in-plane retardation was 100 nm. The cycloolefin polymer substrate with a thickness of 25 μm was used. Except for the above, an optical film was obtained in the same manner as in Example B1.

[0290] <Example B7> In Example B7, a 50 μm thick sheet was used instead of a triacetyl cellulose-based substrate. Chloroolefin polymer-based substrate (product name: ZEONORFILM (registered trademark) ZF14-05 The optical filter was prepared in the same manner as in Example B1, except that "0" (manufactured by Zeon Corporation) was used. I got the idea.

[0291] <Example B8> In Example B8, a 30 μm thick acetylcellulose substrate was used instead of the triacetylcellulose substrate. Kryl resin base material (product name "OXIS (registered trademark)-ZU (30 μm)", Okura Kogyo Co., Ltd. An optical film was obtained in the same manner as in Example B1, except that a polyimide film (manufactured by Co., Ltd.) was used.

[0292] <Example B9> In Example B9, instead of the triacetyl cellulose-based substrate, a 40 μm thick acrylic Kryl resin substrate (product name "OXIS (registered trademark)-ZU (40 μm)", Okura Kogyo Co., Ltd. An optical film was obtained in the same manner as in Example B1, except that a polyimide film (manufactured by Co., Ltd.) was used.

[0293] <Example B10> In Example B10, instead of the triacetyl cellulose-based substrate, A polyethylene terephthalate substrate (PET substrate, in-plane phase shift) with a thickness of 40 μm was fabricated. The same procedure as in Example B1 was repeated except that the following was used: Re: 600 nm, Nz coefficient: 20 I got a film of the school.

[0294] (Preparation of PET substrate) First, 1 kg of PET (melting point 258°C, central absorption wavelength: 320 nm) and 0.1 kg Ultraviolet absorber (2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazine Non-4-one) was melted and mixed in a kneader at 280°C to produce pellets containing ultraviolet absorbers. The pellets and PET with a melting point of 258°C were fed into a single screw extruder and heated at 280°C. The mixture is melt-kneaded at 25°C, extruded from a T-die, and cast onto a casting drum whose surface temperature is controlled at 25°C. The UV absorber in the casting film was The amount was 1 part by mass per 100 parts by mass of PET.

[0295] The obtained casting film was heated with a group of rolls set at 95°C, and then stretched. Distance between rolls A and B is 400 mm (the start point is roll A and the end point is roll B). The film temperature at the 150 mm point of the two nip rolls is 10 To keep the temperature at 3℃, a radiation heater was used to create turbulence on both sides of the film. While being heated, the film was stretched 3.5 times in the machine direction and then cooled once.

[0296] Next, both sides of the uniaxially stretched film are subjected to a corona discharge treatment in air to form a base film. The wetting tension was set to 55 mN / m, and the glass transition temperature of 1 A polyester resin with a glass transition temperature of 82°C and an average particle size of 1 A lubricating layer is formed by in-line coating of a lubricating layer coating solution containing 0.00 nm silica particles. Ta.

[0297] Next, the uniaxially stretched film is introduced into the tenter, preheated with hot air at 95°C, and then heated at 105°C on the first stage. In the second stage, the film was stretched 3.8 times in the width direction at a temperature of 140° C. The transverse stretching section was 2 When divided, the film stretch amount at the midpoint of the transverse stretching section (film width at the measurement point - The film width before stretching is stretched in two stages so that it is 80% of the stretch amount at the end of the transverse stretching section. The transversely stretched film was then heated in a tenter at a temperature gradually increasing from 180°C to 200°C. Heat treatment is performed with hot air at 45°C, followed by 1% relaxation treatment in the width direction under the same temperature conditions. After quenching to 100℃, the film is relaxed by 1% in the transverse direction, then wound up and biaxially stretched. A PET substrate was obtained.

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

[0299] <Comparative Example B1> The composition 3 for hard coat layer was measured with a Meyer bar to measure 210 mm×297 mm (A 4 sizes) and a 25μm-thick triacetyl cellulose-based substrate (product name "FUJITAC The mixture was applied to the surface of a film made of a PET film (TJ25UL, manufactured by Fujifilm Corporation) to form a coating film. Then, dry air at 50°C is passed through the formed coating at a flow rate of 0.5 m / s for 30 seconds. This evaporates the solvent in the coating, and the ultraviolet rays are exposed to a nitrogen atmosphere (oxygen concentration below 200 ppm). The accumulated light intensity is 500mJ / cm 2 The coating was cured by irradiating the film so that the The optical filter has a hard coat layer having a thickness of 6 μm on a triacetyl cellulose substrate. I got the idea.

[0300] <Comparative example B2> In Comparative Example B2, the composition for hard coat layer was replaced with the composition for hard coat layer 3. An optical film was obtained in the same manner as in Comparative Example B1, except that No. 5 was used.

[0301] <Comparative Example B3> In Comparative Example B3, the composition for hard coat layer was replaced with the composition for hard coat layer 3. 4 was used, and composition 3 for hard coat layer was used instead of composition 4 for hard coat layer. Except for the above, an optical film was obtained in the same manner as in Example B1.

[0302] <Comparative example B4> In Comparative Example B4, when the first coating film was cured, ultraviolet rays were irradiated in a nitrogen atmosphere (oxygen concentration 20 0ppm or less) with an integrated light intensity of 400mJ / cm 2 Other than that, the actual An optical film was obtained in the same manner as in Example B1.

[0303] <Comparative Example B5> In Comparative Example B5, the composition for hard coat layer was replaced with the composition for hard coat layer 3. 4 was used, and composition 5 for hard coat layer was used instead of composition 4 for hard coat layer. Except for the above, an optical film was obtained in the same manner as in Example B1.

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

[0305] After preparing the composition 6 for hard coat layer, the composition 6 for hard coat layer was The size is 210mm x 297mm (A4 size) and the thickness is 25μm. Surface of cellulose-based substrate (product name "FUJITAC TJ25UL", manufactured by FUJIFILM Corporation) The coating was then applied to the coating at a flow rate of 0.5 m / s for 5 min. The solvent in the coating film was evaporated by flowing dry air at 0 °C for 30 seconds, and ultraviolet rays were irradiated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) so that the integrated light quantity became 400 mJ / cm 2 to cure the coating film and form a first coating film with a cured film thickness of 3 μm. After forming the cured first coating film, the composition 4 for the hard coat layer was applied to the surface of the first coating film

[0306] 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 for 30 seconds to evaporate the solvent in the second coating film, and ultraviolet rays were irradiated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) so that the integrated light quantity became 200 mJ / cm to cure the second coating film and form a second coating film with a cured 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 was obtained on the triacetyl cellulose-based substrate. In addition, 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. 2 to become and a hard coat layer having a film thickness of 6 μm composed of the cured first coating film and the cured second coating film was obtained on the triacetyl cellulose-based substrate. In addition, 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. <Observation of the presence of an interface in the hard coat layer by TOF-SIMS>

[0307] <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, the intensity of secondary ions derived from each component in the hard coat layer was measured using a time-of-flight secondary ion mass spectrometer (product name "TOF.SIMS5", manufactured by ION-TOF). 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. Then after and 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. Then The intensity of secondary ions originating from each component was measured under the following measurement conditions, and the depth profile was calculated. From this depth profile, the hard coat layer was Identify the bisector that divides the layer into two equal parts and the back surface of the hard coat layer, and identify the front surface of the hard coat layer. The first region is 0.3 μm thick and includes the hard coat layer in the depth direction. The second region is 0.3 μm thick and includes the bisector, and the second region is 0. The hard coat is applied from the boundary between the 3 μm third region and the triacetyl cellulose substrate side of the first region. The ultraviolet absorption in the first to third regions was calculated. Intensity of secondary ions from agent 1 I U1 , I U2 , I U3 , secondary ions from fluorine-containing compounds Intensity I F1 , I F2 , I F3 , and the intensity of secondary ions from silicon-containing compounds I S 1, I S2 , I S3 Calculate 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 In addition, purple The secondary ion from the ultraviolet absorber 1 is C6H4N3 - and acrylic esters and acetate compounds. The secondary ion derived is C2H3O2 - The secondary ions originating from fluorine-containing compounds are F - year , SiO2 as secondary ions derived from silicon-containing compounds - In addition, nitrogen-containing organic matter CN as a secondary ion derived from - The strength of the hard coat layer was measured. The secondary ions CH from acrylate and acetate compounds in the profile 3O2 - and the secondary ion C6H4N3 from UV absorber 1. - The intersection position of Moreover, the second region was set so that the bisector was located in the center of the second region. (Measurement conditions) Secondary ion polarity: negative ·Mass range (m / z): 0~3000 Raster size: 200μm Number of scans: 1 scan / cycle Number of pixels (per side): 128 pixels Measured vacuum level (before sample introduction): 4×10 -7 Pa or less Charge neutralization: Yes ·Late acceleration: 10kV Primary ion: Bi3 ++ Primary ion acceleration voltage: 30 kV 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): approx. 1400

[0308] <Pencil hardness> The surfaces of the optical films according to Examples B1 to B11 and Comparative Examples B1 to B6 (hard coat The pencil hardness of each layer was measured. The surface of the optical film cut to a size of 1.5 mm was subjected to a pencil hardness test using a pencil hardness tester (product name: "Pencil Scratch Test"). Using a coating hardness tester (electric type, manufactured by Toyo Seiki Seisakusho Co., Ltd.), the temperature was 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 placed on the The test is performed by applying a load of 0 g and moving the sample at a speed of 3 mm / sec. The pencil hardness is the highest value at which the surface of the optical film 10 is not scratched in the pencil hardness test. The hardness was measured by using multiple pencils with different hardness. The pencil hardness test was carried out 5 times with each pencil, and the surface of the optical film was scratched 4 or more times out of 5. In the case where the pencil did not stick to the optical film, the surface of the optical film was not scratched with the pencil of this hardness. It was determined that

[0309] <Scratch resistance test> The surfaces of the optical films according to Examples B1 to B11 and Comparative Examples B1 to B6 (hard coat The scratch resistance test was carried out on the surface of the film (layer) at a temperature of 23°C and a relative humidity of 50%. Specifically, first, a 50 mm x 50 mm piece of optical film was cut out. In contrast, #0000 steel wool (product name "Bonstar", Japan Steel Wool Co., Ltd.) Company) at 100g / cm 2 A scratch resistance test was conducted by rubbing the material back and forth 10 times while applying a load of The optical film was visually observed to see whether scratches were present on the surface. The evaluation results were as follows: I passed. A: No injuries were found. B: A few scratches were found, but not to the extent that would cause any problems in practical use. C: The damage was clearly visible.

[0310] <Durability test> A durability test was performed on the optical films according to Examples B1 to B11 and Comparative Examples B1 to B6. Specifically, the optical film was cut into a size of 100 mm x 100 mm and then subjected to a Place it in a test device (product name "Constant Temperature and Humidity Chamber PL-1KP", manufactured by Espec Corporation) A durability test was conducted by leaving the product for 240 hours under conditions of a temperature of 85°C and a relative humidity of 85%. The film must be free of defects (contamination of foreign matter), cracks, wrinkles, and dirt. and placed in the durability test apparatus in a flat, curl-free state.

[0311] After the durability test, the hard coat layer was subjected to a temperature of 23°C and a relative humidity of 50%. The presence of any protrusions and the occurrence of any cracks in the hard coat layer were evaluated. The criteria were as follows: A: Neither the presence of precipitates nor cracks was confirmed. B: Either the presence of precipitates or cracks was confirmed. C: Both the presence of precipitates and cracks were confirmed.

[0312] <Spectral transmittance> In the optical films according to Examples B1 to B4, B6, B8, and B10, the temperature was 23° C. and 50% relative humidity at wavelengths of 380 nm, 400 nm, 410 nm, and 440 nm. The spectral transmittance at 100 nm was measured in the same manner and with the same method as that described in Example A. The measurements were performed under the same measurement conditions.

[0313] <Yellow Index (YI)> The yellow index of the optical films according to Examples B1 to B4, B6, B8, and B10 is The yellow index was measured in the same manner and under the same conditions as in Example A. Measured.

[0314] <Total light transmittance measurement> In the optical films according to Examples B1 to B4, B6, B8, and B10, the haze meter (Product name "HM-150", manufactured by Murakami Color Research Laboratory) was used at a temperature of 23°C and relative humidity of 20°C. The total light transmittance was measured in accordance with JIS K7361:1997 under an environment of 50% humidity. Specifically, the total light transmittance was measured in the same manner as that described in Example A. The measurements were performed under similar conditions.

[0315] <Haze measurement> In the optical films according to Examples B1 to B4, B6, B8, and B10, the haze meter (Product name "HM-150", manufactured by Murakami Color Research Laboratory) was used at a temperature of 23°C and relative humidity of 20°C. The haze value (total haze value) was measured according to JIS K7136:2000 under a 50% humidity environment. Specifically, the total light transmittance was measured in the same manner as the haze value described in the column of Example A. The measurements were performed under the same conditions as above.

[0316] <Visibility evaluation> The optical films according to Examples B1 to B4, B6, B8, and B10 were evaluated for visibility. Specifically, the visibility evaluation was performed in the same manner as in the visibility evaluation described in the column of Example A. and evaluated using similar criteria.

[0317] <Flexibility evaluation> (1) Evaluation of cracks and breakage after folding test The optical films according to Examples B1 and B5 to B11 were subjected to a folding test. Specifically, the folding test was carried out to evaluate the crack length and breakage of Example A after the folding test. The folding test was performed in the same manner and under the same measurement conditions as those in the folding test described in the section on breakage evaluation. The cracking and breaking evaluation was performed according to the same procedure as described in the "Cracking and breaking evaluation after folding test" column of Example A. The evaluation was performed using the same evaluation method and criteria.

[0318] (2) Evaluation of folds after folding test The appearance of the optical films according to Examples B1 and B5 to B11 was observed after the folding test. The bending test was carried out to evaluate whether or not a crease was formed at the bent portion of the optical film. The test was performed in the same manner as the folding test described in the "Evaluation of folding habits after folding test" column of Example A. The folding test was performed under the same conditions as those of Example A. The evaluation was performed according to the evaluation method and similar criteria described in the fold crease evaluation section.

[0319] (3) Evaluation of microcracks after folding test The appearance of the optical films according to Examples B1 and B5 to B11 was observed after the folding test. The bending portion of the optical film was evaluated for the occurrence of microcracks. The folding test was carried out according to the method described in the column for evaluating microcracks after folding test in Example A. The test was carried out in the same manner and under the same conditions as the folding test. The evaluation method described in the column for microcrack evaluation after folding test in Example A and The evaluation was based on the same criteria.

[0320] The results are shown in Tables 6 to 9 below. In addition, in the optical film according to Example B1, Depth profiles measured by time-of-flight secondary ion mass spectrometry at 100 nm and 100 nm in the presence of fluorine were shown. [Table 6]

[0321] [Table 7]

[0322] [Table 8]

[0323] [Table 9]

[0324] As shown in Table 6, in the optical films according to Comparative Examples B1 to B6, I U2 / I U1 is outside the range of 1.1 to 4.0, or I U3 / I U2 is 1.2 or higher 4.0 Since the results were outside the ranges shown below, the pencil hardness, scratch resistance and durability were poor. In the optical films according to Examples B1 to B11, I U2 / I U1 is 1.1 or more4. 0 or less and I U3 / I U2 Since the value was between 1.2 and 4.0, we aimed to make it thinner. At the same time, good pencil hardness, good scratch resistance and good durability were obtained. CN as a secondary ion derived from nitrogen-containing organic matter - The strength of C6H4N3 - The same intensity as Similar results were obtained. In addition, from the graph in FIG. 15, it can be seen that the ultraviolet absorbent 1-derived The minimum intensity of the secondary ions is from the boundary of the first region on the triacetyl cellulose substrate side to the back surface. It is smaller than the minimum intensity of the secondary ions originating from the ultraviolet absorber 1 in the fourth region up to 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 coat 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 contains at least one of an acetyl cellulose-based resin, a cycloolefin polymer-based resin, and a (meth)acrylic resin; At least one of the first functional layer and the second functional layer contains an ultraviolet absorbing agent, 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 a component of the first functional layer and a component of the second functional layer; a total thickness of the first functional layer, the second functional layer, and the mixed layer is 1 μm or more and 10 μm or less; a ratio of a thickness of the mixed layer to a total 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 hardness of the second functional layer is greater than the indentation hardness of the first functional layer; The blue light blocking rate is 20% or more, 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, At least one of the first functional layer and the second functional layer contains an ultraviolet absorbing agent, 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 a component of the first functional layer and a component of the second functional layer; a total 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 hardness of the second functional layer is greater than the indentation hardness of the first functional layer; The blue light blocking rate is 20% or more, 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 , wherein the mixed layer has a thickness of 0.1 μm or more.

4. The optical film according to claim 1 , wherein both the first functional layer and the second functional layer contain the ultraviolet absorbing agent.

5. The optical film according to claim 1 , wherein the first functional layer contains the ultraviolet absorber, and the indentation hardness of the first functional layer is 50 MPa or more and 600 MPa or less.

6. An optical film described in any one of claims 1 to 5, wherein the indentation hardness of the second functional layer is 75 MPa or more and 1000 MPa or less.

7. An optical film described in any one of claims 1 to 6, having a spectral transmittance at a wavelength of 380 nm of less than 10%.

8. An optical film described in any one of claims 1 to 7, having a spectral transmittance at a wavelength of 440 nm of 75% or more.

9. An optical film described in any one of claims 1 to 8, having a yellow index of 15 or less.

10. An optical film described in any one of claims 1 to 9, having a total light transmittance of 80% or more.

11. The optical film according to any one of claims 1 to 10, A polarizer provided on one surface side of the optical film; A polarizing plate comprising:

12. A display element; The optical film according to claim 1 or the polarizing plate according to claim 11, which is disposed on a viewer side relative to the display element; An image display device comprising:

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

Images