JP7322364B2 - Polarizer protective film, transfer body for polarizer protective film, polarizing plate, image display device, and method for producing polarizer protective film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polarizer protective film, a transfer member for a polarizer protective film, a polarizing plate, an image display device, and a method for producing a polarizer protective film.

In recent years, development of image display devices using organic light emitting diode (OLED) elements as display elements is progressing. An image display device using an organic light-emitting diode element is self-luminous, unlike a non-luminous display device represented by a liquid crystal display device, and does not require a light source such as a backlight device. It is possible to reduce the weight.

At present, as a polarizer protective film that protects the polarizer and is arranged closer to the viewer than the polarizer, a cycloolefin polymer substrate (COP substrate) and a hard coat layer provided on the COP substrate are used. is used (see, for example, Patent Document 1).

JP 2016-200709 A

Currently, there is a demand for further reduction in the thickness of image display devices. Although the thickness of the COP substrate used as the substrate of the polarizer protective film is large, it is difficult to reduce the thickness of the COP substrate. A COP substrate cannot be used for the protective film.

On the other hand, the displayed image of the image display device may be observed while wearing sunglasses outdoors, etc. However, if the sunglasses are polarized sunglasses, viewing the displayed image through the polarized sunglasses may reduce the visibility. There is

The present invention has been made to solve the above problems. That is, a polarizer protective film that can be made thinner and can suppress deterioration of visibility even when a displayed image is observed through polarized sunglasses, a transfer body for a polarizer protective film comprising the same, and a polarizing plate , and an image display device, and a method for producing such a polarizer protective film.

The present invention includes the following inventions.
[1] A substrate-less polarizer protective film, comprising: a first resin layer containing a cured product of a first ionizing radiation-curable resin composition; a second resin layer containing a cured product of a second ionizing radiation-curable resin composition containing at least a liquid crystal compound;
A polarizer protective film, comprising:

[2] The polarizer protective film according to [1], wherein the thickness of the second resin layer is 0.1 μm or more and 10 μm or less.

[3] The polarizer protective film according to the above [1] or [2], wherein the in-plane retardation at a wavelength of 589 nm of the polarizer protective film is 80 nm or more and 220 nm or less.

[4] The polarizer protective film according to any one of [1] to [3] above, wherein the indentation hardness of the first resin layer is higher than the indentation hardness of the second resin layer.

[5] The polarizer protective film according to any one of [1] to [4] above, wherein the polarizer protective film has a thickness of 15 μm or less.

[6] The polarizer protective film according to any one of [1] to [5] above, wherein the first resin layer contains an ultraviolet absorber.

[7] Polarized light comprising the polarizer protective film according to any one of [1] to [6] above and a release film provided on the first resin layer side of the polarizer protective film Transfer material for child protection film.

[8] A polarizer and the polarizer protective film according to any one of [1] to [6] attached to the polarizer, wherein the second resin of the polarizer protective film A polarizing plate, wherein a layer is positioned closer to the polarizer than the first resin layer.

[9] A display element, and the polarizing plate according to [8] above arranged on the viewer side of the display element, wherein the polarizer protective film is positioned on the viewer side of the polarizer image display device.

[10] The display element is a light-emitting element, wherein the emission peak wavelength of blue light of the light-emitting element is λ1, the absorption start wavelength of the first resin layer is λ2, and the absorption start wavelength of the second resin layer is λ3. The image display device according to [9] above, which satisfies the relationship of λ1>λ2>λ3.

[11] The image display device according to [9] or [10] above, wherein the display element is an organic light-emitting diode.

[12] A method for producing a polarizer protective film, wherein a first ionizing radiation-curable resin composition is applied to one surface of a release film and cured by irradiation with ionizing radiation to form a first resin layer. forming a second resin layer on the first resin layer by applying a second ionizing radiation-curable resin composition containing a liquid crystal compound to the second resin layer side and curing by irradiation with ionizing radiation; and peeling the release film from the first resin layer.

INDUSTRIAL APPLICABILITY According to the present invention, a polarizer protective film that can be made thinner and can suppress deterioration of visibility even when a displayed image is observed through polarized sunglasses, and a transfer for a polarizer protective film comprising the same A body, a polarizing plate, an image display device, and a method for manufacturing such a polarizer protective film can be provided.

1 is a schematic configuration diagram of a transfer member for a polarizer protective film according to an embodiment; FIG. It is the figure which showed typically the manufacturing process of the transfer body for polarizer protective films which concerns on embodiment. It is the figure which showed typically the manufacturing process of the transfer body for polarizer protective films which concerns on embodiment. It is the figure which showed typically the manufacturing process of the transfer body for polarizer protective films which concerns on embodiment. 1 is a schematic configuration diagram of an image display device according to an embodiment; FIG.

Hereinafter, a polarizer protective film, a polarizer protective film transfer member, a polarizing plate, and an image display device according to embodiments of the present invention will be described with reference to the drawings. As used herein, the terms "film", "sheet" and the like are not to be distinguished from each other based solely on the difference in designation. Therefore, for example, the term "film" is used to include members that are also called sheets. FIG. 1 is a schematic configuration diagram of a transfer body for a polarizer protective film according to the present embodiment, and FIGS. is. FIG. 5 is a schematic configuration diagram of an image display device according to this embodiment.

[Polarizer protective film and transfer body for polarizer protective film]
A polarizer protective film transfer member 10 shown in FIG. 1 includes a polarizer protective film 20 for protecting the polarizer and a release film 30 laminated on the polarizer protective film 20 .

<<<<Polarizer protective film>>>>
The polarizer protective film 20 does not have a substrate, that is, it is a substrateless film. As used herein, the term "substrate" refers to a support for forming a polarizer protective film and a film or sheet that is present in the polarizer protective film even when the polarizer protective film is used. Examples of the substrate include cellulose acylate substrates such as triacetyl cellulose, cycloolefin polymer substrates, polycarbonate substrates, acrylic substrates, polyester substrates such as polyethylene terephthalate substrates, and glass substrates. Note that the release film 30 is peeled off when the polarizer protective film is used, so it is not regarded as a base material.

From the viewpoint of thinning, the thickness of the polarizer protective film 20 is preferably 20 μm or less. From the viewpoint of low moisture permeability, the lower limit of the thickness of the polarizer protective film 20 is preferably 1 μm or more, 2 μm or more, or 3 μm or more (the larger the value, the more preferable). Moreover, the upper limit of the thickness of the polarizer protective film 20 is preferably 15 μm or less, 13 μm or less, or 10 μm or less (the smaller the value, the better). The thickness of the polarizer protective film 20 is obtained by photographing a cross section of the polarizer protective film 20 using a scanning electron microscope (SEM), measuring the thickness of the polarizer protective film 20 at 10 locations in the cross-sectional image, and measuring the thickness of the polarizer protective film 20. It can be obtained by calculating the arithmetic mean value of only 10 films.

The specific method for taking cross-sectional photographs is as follows. First, a block is prepared by embedding a polarizer protective film cut into a size of 1 mm×10 mm in an embedding resin, and a uniform section having a thickness of about 70 nm to 300 nm without holes is prepared from this block by a general sectioning method. cut out. "Ultramicrotome EM UC7" (Leica Microsystems, Inc.) or the like is used to prepare the sections. Then, the remaining block from which uniform sections without holes or the like were cut out is used as a measurement sample. After that, a cross-sectional photograph of the measurement sample is taken using a scanning electron microscope (SEM) (product name “S-4800”, manufactured by Hitachi High-Technologies Corporation). When taking a cross-sectional photograph using the S-4800, the cross-sectional observation is performed with the detector set to "SE", the acceleration voltage set to "3 kV", and the emission current set to "10 μA". Magnification is appropriately adjusted to 1,000 to 10,000 times, preferably 1,000 to 10,000 times depending on the thickness of the polarizer protective film, while adjusting the focus and observing whether the contrast and brightness of each layer can be distinguished. In order to reduce the measurement deviation of the thickness, it is recommended to measure the thickness of the polarizer protective film at a magnification as low as possible. Further, the aperture is set to "beam monitor aperture 1", the objective lens aperture is set to "2", and the W. D. to "8mm".

The in-plane retardation (in-plane retardation, Re) of the polarizer protective film 20 at a wavelength of 589 nm is preferably 80 nm or more and 220 nm or less. If the in-plane retardation of the polarizer protective film 20 at a wavelength of 589 nm is within the above range, the polarizer protective film 20 functions as a λ/4 retardation film. The lower limit of the in-plane retardation is more preferably 90 nm or more and 100 nm or more (the larger the value, the more preferable), and the upper limit is more preferably 180 nm or less and 155 nm or less (the smaller the value, the more preferable). In the present specification, the "in-plane retardation of the polarizer protective film" is the in-plane retardation of the entire polarizer protective film, and is measured for the entire polarizer protective film. Further, the in-plane retardation of the polarizer protective film is defined by nx as the refractive index in the in-plane slow axis direction of the polarizer protective film, ny as the refractive index in the in-plane direction orthogonal to nx of the polarizer protective film, When the film thickness of the second resin layer is d (nm), it can be represented by the following formula (1).
In-plane retardation (Re) = (nx-ny) x d (1)

The in-plane retardation of the polarizer protective film 20 can be measured as follows. First, an adhesive layer (product name “Panaclean (registered trademark) PD-S1”, Panac Co., Ltd.) is attached to an optically isotropic glass (length 30 mm × width 30 mm, thickness 1 mm), and further protection of the polarizer. The film transfer member is adhered so that the second resin layer is in contact with the adhesive layer and there are no creases or wrinkles. After that, the release film is peeled off from the polarizer protective film to expose the first resin layer to obtain a measurement sample. The polarizer protective film transfer member used for the measurement sample is cut from the central portion of the polarizer protective film transfer member into a size of 40 mm long×40 mm wide. Then, the in-plane retardation (retardation) of this measurement sample at a wavelength of 589 nm is measured using a phase difference measuring device (product name “KOBRA-WR”, manufactured by Oji Scientific Instruments Co., Ltd., measurement spot: diameter 5 mm). The in-plane retardation is measured three times for one measurement sample, and the arithmetic mean value of the values obtained by the three measurements is taken.

When the polarizer protective film 20 is incorporated in a circularly polarizing plate or an image display device, the polarizer protective film 20 is attached to another film via an adhesive layer or adhesive layer. In this case, the in-plane retardation is measured while the film is separated from other films. When peeling off another film from the polarizer protective film 20, first, insert a cutter blade into the edge and peel off the other film. If it is not easily peeled off, do not forcefully peel it off and move on to the next step. Then, it is immersed in warm water of 40° C. for 10 seconds and taken out, which is repeated three times. After that, the degree of peeling of the adhesive layer or adhesive layer is checked with a cutter or the like, and depending on the case, immersion in hot water at 40° C. for 10 seconds and taking out are repeated three more times. After that, the adhesive layer or adhesive layer is slowly peeled off with a tool (thin and flat but without a blade) that does not damage the polarizer protective film. It should be noted that even if the entire surface cannot be peeled off, it is sufficient if the portion to be measured can be peeled off. Further, since the in-plane retardation of the adhesive layer and the adhesive layer itself is at a level that can be almost ignored, they may remain on the polarizer protective film 20 side.

The moisture permeability of the polarizer protective film 20 is preferably 600 g/(m ² ·24 h) or less. If the moisture permeability of the polarizer protective film is 600 g/(m ² ·24 h) or less, the swelling of the polarizer protective film 20 can be suppressed in the durability test. The term “moisture permeability” as used herein refers to a protective film measured under an atmosphere of 40° C. and 90% relative humidity by a method conforming to the moisture permeability test method (cup method) described in JIS Z0208:1976. It means the amount of water vapor passing through in 24 hours (g/(m ² ·24h)). Let the moisture permeability be the arithmetic mean value of the value obtained by measuring 3 times. Note that the moisture permeability of the polarizer protective film 20 is measured with the release film 30 peeled off. The lower limit of the moisture permeability of the polarizer protective film 20 is more preferably 500 g/(m ² ·24 h) or less, 400 g/(m ² ·24 h) or less, or 300 g/(m ² ·24 h) or less (the numerical value is smaller is better).

The polarizer protective film 20 preferably has a haze value (total haze value) of 1% or less. If the haze value of the polarizer protective film 20 is 1% or less, whitening of the screen can be suppressed when the polarizer protective film 20 is used in a mobile device. More preferably, the upper limit of the haze value of the polarizer protective film 20 is 0.5% or less, 0.4% or less, 0.3% or less, or 0.2% or less (the smaller the value, the better).

The haze value can be measured by a method in accordance with JIS K7136:2000 using a haze meter (product name "HM-150", manufactured by Murakami Color Research Laboratory). The haze value of the polarizer protective film 20 is measured with the release film 30 peeled off. The above haze value is obtained by cutting the polarizer protective film into a size of 50 mm × 50 mm, setting it in a state where there are no curls or wrinkles, fingerprints, dust, etc., and three times for one polarizer protective film. Arithmetic mean value of the values obtained by measuring 3 times. In this specification, "measure three times" means not measuring the same place three times but three different places. In the polarizer protective film 20, the visually observed surface is flat, the laminated layers such as the first resin layer are also flat, and the film thickness variation is within the range of ±15%. Therefore, it is considered that by measuring the haze value at three different points of the cut-out polarizer protective film, an approximate average value of the haze values of the entire in-plane of the polarizer protective film can be obtained. The variation in haze value is within ±10% even if the object to be measured is as long as 1 m×3000 m or as large as a 5-inch smartphone. If the polarizer protective film cannot be cut into the above size, for example, the HM-150 has an entrance opening of 20 mmφ for measurement, so a sample size of 21 mm or more in diameter is required. Therefore, the polarizer protective film may be appropriately cut into a size of 22 mm×22 mm or more. When the size of the polarizer protective film is small, the measurement points are set to three by gradually shifting or changing the angle within a range where the light source spot does not deviate.

The polarizer protective film 20 has a spectral transmittance of less than 1% at a wavelength of 380 nm, a spectral transmittance of 0.5% or more and less than 30% at a wavelength of 410 nm, and a spectral transmittance of 440 nm. It is preferable that it is 35% or more. If the spectral transmittance of the polarizer protective film 20 at a wavelength of 380 nm is less than 1%, an excellent blue light shielding rate can be achieved. Further, when the spectral transmittance of the polarizer protective film 20 at a wavelength of 410 nm is 0.5% or more, the yellowishness of the circular polarizer protective film 20 can be suppressed, and the spectral transmittance of the polarizer protective film 20 at a wavelength of 410 nm is less than 30%. , excellent blue light shielding can be achieved without adversely affecting transmitted light. If the spectral transmittance of the polarizer protective film 20 at a wavelength of 440 nm is 35% or more, the yellow index is low, the color of the polarizer protective film 20 itself does not turn yellow, and a decrease in transmittance in the visible light region can be suppressed. The lower limit of the spectral transmittance of the polarizer protective film 20 at a wavelength of 410 nm is more preferably 1% or more, and the upper limit is more preferably 25% or less. The lower limit of the spectral transmittance of the polarizer protective film 20 at a wavelength of 440 nm is more preferably 40% or more and 45% or more (the larger the value, the more preferable).

The spectral transmittance is cut into a size of 50 mm × 50 mm, and a spectrophotometer (product name “UV-2450”, Shimadzu Corp., light source: tungsten lamp and deuterium lamp), the second resin layer side of the polarizer protective film is placed on the light source side, under the following measurement conditions, wavelengths of 380 nm, 410 nm, and At 440 nm, the transmittance for at least 5 points is measured between 1 nm before and after each, and the average value is calculated. The spectral transmittance at wavelengths of 380 nm, 410 nm, and 440 nm is the arithmetic mean value of the values obtained by measuring three times. If the spectrum of the spectral transmittance has undulations, a smoothing process may be performed with a delta of 5.0 nm.
(Measurement condition)
・Wavelength range: 300 nm to 780 nm
・Scanning speed: high speed ・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: 360 nm
・S/R switching: standard ・Detector: PM
Autozero: performed at 550 nm after baseline scan

The polarizer protective film 20 preferably has a spectral transmittance of 5% or more and 25% or less at a wavelength of 420 nm. By setting the spectral transmittance at a wavelength of 420 nm within this range, it is possible to exhibit blue light shielding performance, suppress deterioration in visibility due to coloring, and ensure transparency. The spectral transmittance at a wavelength of 420 nm in the polarizer protective film 20 is also measured in the same manner as the spectral transmittance at a wavelength of 380 nm.

The polarizer protective film 20 preferably has a yellow index (YI) of 15 or less. If the YI of the polarizer protective film 20 is 15 or less, the polarizer protective film 20 can be suppressed from yellowing, and can be applied to applications requiring transparency. The yellow index (YI) is obtained by cutting the polarizer protective film into a size of 50 mm × 50 mm and peeling off the release film with a spectrophotometer (product name "UV-2450", manufactured by Shimadzu Corporation, light source : Tungsten lamp and deuterium lamp). From the transmittance of the polarizer protective film at a wavelength of 300 nm to 780 nm measured in a state where the second resin layer side of the polarizer protective film is on the light source side, JIS Z8722: 2009 Chromaticity tristimulus values X, Y, and Z are calculated according to the formula described in ASTM D1925:1962 from the tristimulus values X, Y, and Z. The yellow index (YI) is calculated three times by measuring the transmittance at a wavelength of 300 nm to 780 nm for one polarizer protective film three times, and the arithmetic average value of the values obtained by three calculations is taken. . In UV-2450, the yellow index is calculated by reading the transmittance measurement data on the monitor connected to UV-2450 and checking the "YI" item in the calculation items. . The conditions for measuring the transmittance at wavelengths of 300 nm to 780 nm are the same as the conditions for measuring the spectral transmittance at wavelengths of 380 nm, 410 nm, and 440 nm. The lower limit of YI is originally preferably lower from the viewpoint of ensuring high transparency, but considering that blue light cut performance is also given, it is more preferably 1 or more, 2 or more, or 3 or more (the numerical value is preferably larger). However, if YI is too large, yellowishness may become stronger. Therefore, the upper limit of YI is more preferably 10 or less, 7 or less, or 6 or less (the smaller the number, the better).

When the polarizer protective film 20 was subjected to a mandrel test according to JIS K5600-5-1:1999 (a test in which a sample was wrapped around a metal cylinder of 2 mm to 32 mm), cracks were found in the polarizer protective film 20. It is preferable that the minimum diameter of the cylinder is 6 mm or less when no crack occurs. Excellent flexibility can be obtained if the minimum diameter is 6 mm or less. The mandrel test is performed by cutting the polarizer protective film into a size of 50 mm x 50 mm, peeling off the release film, and winding it around a cylinder so that the first resin layer is on the inside.

When the polarizer protective film 20 is incorporated in a circularly polarizing plate or an image display device, the polarizer protective film 20 is attached to another film via an adhesive layer or adhesive layer. 3, the moisture permeability, the haze value, the spectral transmittance, and the YI are measured and the mandrel test is performed after peeling off other films from the polarizer protective film 20 by the method described above. Even if there is such a peeling process, it does not greatly affect each measurement.

From the viewpoint of obtaining flexibility, the surface of the polarizer protective film 20 (the surface of the first resin layer 21) after peeling the release film 30 has a hardness (pencil hardness) of 3B to 3B when measured by a pencil hardness test. H is preferred. In the pencil hardness test, a transfer body for a polarizer protective film cut into a size of 50 mm × 100 mm was adhered to a glass plate with an acrylic ionizing radiation-curable adhesive so as not to break or wrinkle, and then released from the polarizer protective film. With the film peeled off and the surface of the first resin layer exposed, a pencil hardness tester (product name "pencil scratch coating film hardness tester (electric type)", Toyo Co., Ltd.) is applied to the surface of the first resin layer. (manufactured by Seiki Seisakusho), a pencil (product name "Uni", manufactured by Mitsubishi Pencil Co., Ltd.) is moved at a moving speed of 3 mm/sec while applying a load of 300 g. The pencil hardness is the highest hardness at which the surface of the polarizer protective film 20 was not scratched in the pencil hardness test. In addition, when measuring the pencil hardness, a plurality of pencils with different hardness are used. If no scratches were found, it is determined that the surface of the polarizer protective film 20 was not scratched by the pencil with this hardness. The above-mentioned flaw refers to a flaw visually recognized when the surface of the polarizer protective film 20 subjected to the pencil hardness test is observed through transmission under a fluorescent lamp.

Applications of the polarizer protective film 20 are not particularly limited, and examples thereof include personal computers (PCs) including notebook personal computers, smartphones, tablet terminals, wearable terminals, digital signage, and image display devices such as televisions.

The polarizer protective film 20 may be cut into a desired size, or may be in the form of a roll. When the polarizer protective film 20 is cut to a desired size, the size of the polarizer protective film is not particularly limited, and the application (for example, when used in an image display device, the display of the image display device) It is appropriately determined according to the size of the surface). Specifically, the size of the polarizer protective film 20 may be, for example, 1 inch or more and 500 inches or less, or may be 2.8 inches or more and 500 inches or less. As used herein, the term "inch" means the length of the diagonal when the polarizer protective film has a square shape, the diameter when it has a circular shape, and the diameter when it has an elliptical shape. It shall mean the average value of the sum of the minor axis and the major axis. Here, when the polarizer protective film has a square shape, the aspect ratio of the polarizer protective film when calculating the above inches is not particularly limited as long as there is no problem with the display surface of the image display device. For example, height:width=1:1, 4:3, 16:10, 16:9, 2:1, and the like. However, particularly in in-vehicle applications and digital signage, which are rich in design, the aspect ratio is not limited to such an aspect ratio. In addition, when the size of the polarizer protective film 20 is large, the A5 size (148 mm×210 mm) is cut out from an arbitrary position, and then the size of each measurement item is cut out.

The polarizer protective film 20 includes a first resin layer 21 and the first resin layer 21 arranged on one side of the first resin layer 21 . The polarizer protective film 20 further includes a third resin layer 23 between the first resin layers 21 , but the third resin layer 23 may not be included.

<<<first resin layer>>>
The first resin layer 21 is a layer containing a cured product of the first ionizing radiation-curable resin composition. The first resin layer 21 is a layer that functions as a hard coat layer.

The first resin layer 21 preferably has an absorption start wavelength in a wavelength range of 360 nm or more and 430 nm or less. By using an ultraviolet absorber having an absorption start wavelength in this wavelength range, it is possible to suppress absorption of blue light emitted from a light emitting element, which will be described later, and to suppress deterioration of the second resin layer 22 due to ultraviolet rays. The first resin layer 21 having an absorption start wavelength in the above wavelength range is obtained by containing an ultraviolet absorber, which will be described later.

The indentation hardness of the first resin layer 21 is preferably higher than the indentation hardness of the second resin layer 22 . Since the indentation hardness of the first resin layer 21 is higher than the indentation hardness of the second resin layer 22, it is possible to achieve both foldability and impact resistance in which members inside the display device are less likely to be damaged. .

The indentation hardness of the first resin layer 21 is preferably 100 MPa or more and 600 MPa or less. If the indentation hardness of the first resin layer 21 is 100 MPa or more, a desired hardness can be obtained and a decrease in scratch resistance can be suppressed. A resin layer 21 can be obtained. The lower limit of the indentation hardness of the first resin layer 21 is preferably 150 MPa or more, and the upper limit is preferably 500 MPa or less. The term "indentation hardness" used herein is a value obtained from a load-displacement curve from loading to unloading of the indenter.

The indentation hardness (H _IT ) can be measured using TI950 TriboIndenter manufactured by HYSITRON. Specifically, first, a block is prepared by embedding a polarizer protective film cut into a size of 1 mm×10 mm with an embedding resin to prepare a measurement sample suitable for hardness measurement by the nanoindentation method. "Ultramicrotome EM UC7" (Leica Microsystems, Inc.) or the like can be used to prepare a sample for measurement. Next, the measurement sample is fixed on the stage of TI950 TriboIndenter manufactured by HYSITRON so that the surface of the measurement sample into which the indenter is pushed is parallel to the mounting surface of the stage. Then, a Berkovich type indenter was applied at a load rate of 10 μN/sec to a flat portion at the center of the cross section of the resin layer by a load control method so that the maximum indentation load was 300 μN, and a load from 0 μN to 300 μN was applied in 30 seconds. After pressing into the resin layer while holding the load at 300 μN for 5 seconds, the load is removed from 300 μN to 0 μN in 30 seconds. Then, the indentation depth h (nm) corresponding to the indentation load F (N) at this time is continuously measured to create a load-displacement curve. From the created load-displacement curve, the indentation hardness H _IT , the maximum indentation load F _max (N) as in the following formula (2), and the projected area A _p (mm ² ) where the indenter and the resin layer are in contact It can be obtained by dividing by The indentation hardness is the arithmetic mean value of the values obtained by measuring 10 points.
_HIT = _Fmax / _Ap (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 the value at the intersection of the horizontal axis (displacement) and the tangent line of the unloading curve at F _max .

The film thickness of the first resin layer 21 is preferably 0.5 μm or more and 15 μm or less. If the film thickness of the first resin layer 21 is 0.5 μm or more, it is possible to obtain hardness capable of preventing scratches during the production process. can be suppressed. More preferably, the lower limit of the film thickness of the first resin layer 21 is 1 μm or more, 2 μm or more, or 3 μm or more (the larger the value, the more preferable), and the upper limit is 18 μm or less, 15 μm or less, or 10 μm or less. preferable.

The film thickness of the first resin layer is determined by photographing a cross section of the first resin layer using a scanning transmission electron microscope (STEM) or a transmission electron microscope (TEM), and measuring the thickness of the first resin layer in the image of the cross section. The film thickness is measured at 10 points, and the arithmetic mean value of the film thickness at 10 points is taken. A specific method for taking cross-sectional photographs will be described below. First, a block was prepared by embedding a polarizer protective film cut into a size of 1 mm×10 mm in an embedding resin, and a uniform section having a thickness of 70 nm or more and 100 nm or less without holes was prepared from the block by a general section preparation method. cut out. "Ultramicrotome EM UC7" (Leica Microsystems, Inc.) or the like can be used to prepare the sections. Then, a uniform slice without holes or the like is used as a measurement sample. After that, using a scanning transmission electron microscope (STEM) (product name “S-4800”, manufactured by Hitachi High-Technologies Corporation), a cross-sectional photograph of the measurement sample is taken. When the cross-sectional photograph is taken, the cross-sectional observation is performed with the detector set to "TE", the acceleration voltage set to 30 kV, and the emission set to "10 .mu.A." Magnification is appropriately adjusted between 5,000 and 200,000 times while adjusting the focus and observing whether each layer can be distinguished in terms of contrast and brightness. A preferable magnification is 10,000 to 100,000 times, more preferable magnification is 10,000 to 50,000 times, and the most preferable magnification is 25,000 to 50,000 times. When taking a cross-sectional photograph, the aperture is set to 3 for the beam monitor diaphragm, the objective lens diaphragm is set to 3, and the W.F. D. may be 8 mm. When measuring the film thickness of the first resin layer, it is important that the interfacial contrast between the first resin layer and another layer (for example, the third resin layer) can be observed as clearly as possible when the cross section is observed. becomes. If this interface is difficult to see due to insufficient contrast, dyeing such as osmium tetroxide, ruthenium tetroxide, or phosphotungstic acid will make the interface between the organic layers easier to see. Further, the interface contrast may be difficult to understand at high magnification. In that case, the low magnification is also observed at the same time. For example, observe at two high and low magnifications, such as 25,000 times and 50,000 times, or 50,000 times and 100,000 times, determine the above arithmetic average value at both magnifications, and further calculate the average value as the first resin. It is the value of the film thickness of the layer.

<<First ionizing radiation curable resin composition>>
The first ionizing radiation-curable resin composition is a resin composition that is cured by ionizing radiation, and contains at least an ionizing radiation-polymerizable compound that constitutes the resin contained in the cured product. The ionizing radiation-curable resin composition may contain an ultraviolet absorber, a solvent-drying resin, a thermosetting compound, a polymerization initiator, a solvent, etc., in addition to the ionizing radiation-polymerizable compound.

The content ratio (solid content) of the raw material in the first ionizing radiation-curable resin composition is not particularly limited, but is preferably 5% by mass or more and 70% by mass or less, more preferably 25% by mass or more and 60% by mass or less.

In the first ionizing radiation curable resin composition, conventionally known dispersants, Surfactants, antistatic agents, silane coupling agents, thickeners, anti-coloring agents, coloring agents (pigments, dyes), antifoaming agents, leveling agents, flame retardants, adhesion promoters, polymerization inhibitors, antioxidants , a surface modifier, a lubricating agent, and the like may be added.

The method for preparing the first ionizing radiation-curable resin composition is not particularly limited as long as each component can be uniformly mixed, and for example, it can be performed using a known device such as a paint shaker, bead mill, kneader, or mixer.

When ultraviolet rays are used as the ionizing radiation used for curing the first ionizing radiation-curable resin composition, examples of ultraviolet light sources include ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arc lamps, black light fluorescent lamps, and metal halides. A light source such as a lamp can be used. As the wavelength of ultraviolet rays, a wavelength range of 190 to 380 nm can be used. Specific examples of the electron beam source include various electron beam accelerators such as Cockcroftwald type, Vandegraft type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type.

<Ionizing Radiation Polymerizable Compound>
The ionizing radiation polymerizable compound has at least one ionizing radiation polymerizable group. As used herein, the term "ionizing radiation-polymerizable group" refers to a functional group capable of undergoing a polymerization reaction upon exposure to ionizing radiation. Examples of ionizing radiation polymerizable groups include ethylenically unsaturated groups such as (meth)acryloyl groups, vinyl groups, and allyl groups. In addition, the "(meth)acryloyl group" in this specification is meant to include both "acryloyl group" and "methacryloyl group". Moreover, visible light, ultraviolet rays, X-rays, electron beams, α-rays, β-rays, and γ-rays are examples of the ionizing radiation irradiated when polymerizing the ionizing radiation-polymerizable compound.

Examples of the ionizing radiation-polymerizable compound include ionizing radiation-polymerizable monomers, ionizing radiation-polymerizable oligomers, and ionizing radiation-polymerizable prepolymers, and these can be appropriately adjusted and used. As the ionizing radiation-polymerizable compound, a combination of an ionizing radiation-polymerizable monomer and an ionizing radiation-polymerizable oligomer or ionizing radiation-polymerizable prepolymer is preferable.

(Ionizing radiation polymerizable monomer)
As the ionizing radiation-polymerizable monomer, a polyfunctional monomer having two or more ionizing radiation-polymerizable functional groups (that is, bifunctional) is preferable. Examples of ionizing radiation-polymerizable monomers include ionizing radiation-polymerizable monomers into which modifying groups such as alkylene oxide-modified, urethane-modified, epoxy-modified, and alkoxy-modified are introduced. Among these, alkylene oxide-modified (meth)acrylates are preferable from the viewpoint of obtaining a protective film having good releasability from a release film, tackiness, and high mechanical strength. Alkylene oxides include methylene oxide, ethylene oxide, propylene oxide, butylene oxide and the like.

Among these, ethylene oxide-modified (EO-modified) acrylate and propylene oxide-modified (PO-modified) acrylate are more preferable from the viewpoint of obtaining good peelability and scratch resistance. Furthermore, among these, PO-modified acrylates are particularly preferable because they have a good balance between releasability and scratch resistance.

(ionizing radiation polymerizable oligomer)
Ionizing radiation polymerizable oligomers include oligomers such as urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, polyfluoroalkyl (meth)acrylate, and silicone (meth)acrylate. mentioned.

(Ionizing radiation polymerizable prepolymer)
The ionizing radiation polymerizable prepolymer is preferably 10,000 or more and 80,000 or less, more preferably 10,000 or more and 40,000 or less. If the weight-average molecular weight exceeds 80,000, the coating aptitude is lowered due to the high viscosity, and the appearance of the resulting protective film may be deteriorated. Ionizing radiation polymerizable prepolymers include prepolymers such as urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, polyfluoroalkyl (meth)acrylate, and silicone (meth)acrylate. etc. Among these, urethane acrylate prepolymers are preferred from the viewpoint of increasing interlayer adhesion with the core layer.

A suitable combination of the ionizing radiation-polymerizable monomer and the ionizing radiation-polymerizable prepolymer is that the ionizing radiation-polymerizable monomer is an EO-modified acrylate and the ionizing radiation-polymerizable prepolymer is a urethane acrylate prepolymer.

The ionizing radiation-polymerizable monomer and the ionizing radiation-polymerizable prepolymer are preferably contained at a ratio of 90:10 to 70:30. By containing the ionizing radiation-polymerizable monomer and the ionizing radiation-polymerizable prepolymer in this range, the flexibility and toughness can be improved without lowering the hardness.

<Ultraviolet absorber>
The ultraviolet absorbent is not particularly limited as long as it absorbs ultraviolet rays, but for the reason described above, it preferably has an absorption start wavelength in the wavelength range of 360 nm or more and 430 nm or less. The ultraviolet absorber preferably has a maximum absorbance of 0.5 or more in the wavelength range of 360 nm or more and 430 nm or less.

Examples of the ultraviolet absorber having an absorption initiation wavelength in the wavelength range of 360 nm or more and 430 nm or less include at least one of sesamol-type benzotriazole-based compounds and indole-based compounds.

Whether or not the first resin layer 21 contains an ultraviolet absorber is determined by taking a piece of the first resin layer 21 and measuring the piece by infrared spectroscopy (IR). It can be examined by comparing the absorption spectrum with commercially available UV absorbers. The ultraviolet absorber may be contained as a copolymer in the resin forming the first resin layer 21 .

式（Ａ）中、Ｒ^１は、水素原子またはメチル基を表し、Ｒ^２は、炭素数１～６の直鎖状または分岐鎖状のアルキレン基または炭素数１～６の直鎖状または分岐鎖状のオキシアルキレン基を表す。 (Sesamol-type benzotriazole compound)
Examples of sesamol-type benzotriazole compounds include compounds represented by the following general formula (A). A compound represented by the following general formula (A) can absorb light in a wavelength range of 360 nm or more and 400 nm or less. A compound represented by the following general formula (A) is contained as a monomer unit in the resin forming the first resin layer 21 .

In formula (A), R ¹ represents a hydrogen atom or a methyl group, R ² represents a linear or branched alkylene group having 1 to 6 carbon atoms or a linear or branched chain having 1 to 6 carbon atoms represents a chain oxyalkylene group.

The sesamol-type benzotriazole-based compound represented by the above general formula (A) is a derivative from a compound in which sesamol is bonded to the nitrogen atom at the 2-position of the benzotriazole ring, and the benzene moiety of the benzotriazole ring has a polymerizable 2 It has a molecular structure with a heavy bond introduced. The maximum absorption wavelength λ _max is 365 nm or more, and it has a wide UV absorption spectrum covering a wavelength range of 300 nm to 400 nm, and has UV absorption capability up to a long wavelength range around 400 nm.

The sesamol-type benzotriazole compound is not particularly limited, but specific substance names include 2-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole-5 -yl]ethyl methacrylate, 2-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl]ethyl acrylate, 3-[2-(6-hydroxybenzo [1,3]dioxol-5-yl)-2H-benzotriazol-5-yl]propyl methacrylate, 3-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole -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[1,3]dioxol-5-yl)-2H- benzotriazol-5-yloxy]ethyl methacrylate, 2-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yloxy]ethyl acrylate, 2-[3-{ 2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl}propanoyloxy]ethyl methacrylate, 2-[3-{2-(6-hydroxybenzo[1 , 3]dioxol-5-yl)-2H-benzotriazol-5-yl}propanoyloxy]ethyl acrylate, 4-[3-{2-(6-hydroxybenzo[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 }propanoyloxy]butyl acrylate, 2-[3-{2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl}propanoyloxy]ethyl methacrylate, 2 -[3-{2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl}propanoyloxy]ethyl acrylate, 2-(methacryloyloxy)ethyl 2-( 6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole-5 carboxylate, 2-(acryloyloxy)ethyl 2-(6-hydroxybenzo[1,3]dioxol-5-yl) -2H-benzotriazole-5-carboxylate, 4-(methacryloyloxy)butyl 2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole-5-carboxylate, 4-( acryloyloxy)butyl 2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazole-5-carboxylate and the like. In addition, these sesamol-type benzotriazole-based compounds can be used alone or in combination of two or more.

式（Ｂ）中、Ｒ^３は、直鎖状または分岐鎖状のアルキル基またはアラルキル基を表し、Ｒ^４は、－ＣＮまたは－ＣＯＯＲ^５を表し、ここで、Ｒ^５は、置換基を有していてもよいアルキル基またはアラルキル基（ただし、Ｒ^３がメチル基である場合はエチル基を除く。）を表す。 (indole compound)
Examples of indole compounds include compounds represented by the following general formula (B). A compound represented by the following general formula (B) can absorb light in a wavelength range of 380 nm or more and 400 nm or less.

In formula (B), R ³ represents a linear or branched alkyl group or aralkyl group, R ⁴ represents -CN or -COOR ⁵ , where R ⁵ has a substituent represents an alkyl group or aralkyl group which may be substituted (however, when ^R3 is a methyl group, the ethyl group is excluded).

R ³ can have 1 to 12 carbon atoms. Specific examples of R ³ include methyl group, ethyl group, (iso)butyl group, t-butyl group, hexyl group, octyl group, 2-ethylhexyl group, dodecyl group and benzyl group. Specific examples of R ⁵ include the groups exemplified for R ³ above, β-cyanoethyl group, β-chloroethyl group, ethoxypropyl group, hydroxyalkyl group and alkoxyalkoxyalkyl group. However, when ^R3 is a methyl group, ^R5 is not an ethyl group.

Examples of indole compounds include BONASORB UA-3911 manufactured by Orient Chemical Industry Co., Ltd. and the like.

For example, the ultraviolet absorber may be contained in the first resin layer 21 in an amount of 0.05% by mass or more and 50% by mass or less. By containing the ultraviolet absorber in such a range, it is possible to effectively absorb ultraviolet rays in the wavelength range of 360 nm or more and 400 nm or less. When the ultraviolet absorber is a sesamol-type benzotriazole-based compound, it may be contained in the first resin layer 21 in an amount of 0.1% by mass or more and 50% by mass or less.

<Solvent drying type resin>
Solvent-drying type resins are resins such as thermoplastic resins that form a film only by drying the solvent added to adjust the solid content at the time of coating. By using a solvent-drying type resin together, it is possible to effectively prevent film defects on the coated surface. The solvent-drying resin that can be used in combination with the ionizing radiation-polymerizable compound is not particularly limited, and generally thermoplastic resins can be used.

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

The thermoplastic resin is preferably amorphous and soluble in an organic solvent (especially a common solvent capable of dissolving a plurality of polymers and polymerizable compounds). In particular, styrene-based resins, (meth)acrylic-based resins, alicyclic olefin-based resins, polyester-based resins, cellulose derivatives (cellulose esters, etc.), and the like are preferable from the viewpoint of film formability, transparency, and weather resistance.

<Thermosetting compound>
The thermosetting compound is not particularly limited, and examples thereof include phenol resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, aminoalkyd resins, and melamine-urea cocondensation. Resins, silicon resins, polysiloxane resins, and the like can be mentioned.

<Polymerization initiator>
The polymerization initiator is not particularly limited, and known ones can be used. Specific examples of polymerization initiators include acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, and thioxanthone. , propiophenones, benzils, benzoins, acylphosphine oxides. Moreover, it is preferable to mix and use a photosensitizer, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine, and the like.

As the polymerization initiator, when the ionizing radiation polymerizable compound has a radically polymerizable group, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether and the like are preferably used alone or in combination. Further, when the ionizing radiation polymerizable compound has a cationically polymerizable group, the polymerization initiator may be aromatic diazonium salt, aromatic sulfonium salt, aromatic iodonium salt, metallocene compound, benzoin sulfonate, etc. alone or Use as a mixture is preferred.

The content of the polymerization initiator in the first ionizing radiation-curable resin composition is preferably 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the ionizing radiation-polymerizable compound. If it is 1 part by mass or more, there is no risk that the hardness of the first resin layer 21 will be insufficient. The target surface hardness of the first resin layer (for example, a pencil hardness of B or higher) can be obtained.

The lower limit of the content of the polymerization initiator is more preferably 2 parts by mass or more, and the upper limit is more preferably 8 parts by mass or less. When the content of the polymerization initiator is within this range, the hardness distribution in the film thickness direction does not occur, and the hardness tends to be uniform.

<Solvent>
The solvent can be selected and used according to the type and solubility of the ionizing radiation polymerizable compound to be used. (dioxane, tetrahydrofuran, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.) ), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), water, alcohols (ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates, sulfoxides (dimethylsulfoxide, etc.), amides (dimethylformamide, dimethylacetamide, etc.), etc., and a mixed solvent thereof may be used.

<<<second resin layer>>>
The second resin layer 22 is a layer containing a cured product of the second ionizing radiation-curable resin composition. The second resin layer 22 is a layer that functions as a λ/4 retardation layer.

The film thickness of the second resin layer 22 can be appropriately adjusted in the range of 0.1 μm or more and 10 μm or less in consideration of the in-plane retardation to be provided. As can be seen from the formula for obtaining the in-plane retardation below, the in-plane retardation tends to decrease when the thickness of the second resin layer 22 is reduced. The film thickness of the second resin layer is determined by photographing a cross section of the second resin layer using a scanning transmission electron microscope (STEM) or a transmission electron microscope (TEM). The thickness is measured at 10 points, and the arithmetic mean value of the thickness at 10 points is taken.

The second resin layer 22 preferably has an in-plane retardation (in-plane retardation, Re) of 80 nm or more and 220 nm or less at a wavelength of 589 nm. If the in-plane retardation of the second resin layer 22 at a wavelength of 589 nm is within the above range, the second resin layer 22 functions as a λ/4 retardation layer. The lower limit of the in-plane retardation is more preferably 90 nm or more and 100 nm or more (the larger the value, the more preferable), and the upper limit is more preferably 180 nm or less and 155 nm or less (the smaller the value, the more preferable). For the in-plane retardation of the second resin layer, nx is the refractive index in the in-plane slow axis direction of the second resin layer, ny is the refractive index in the in-plane of the second resin layer in the direction orthogonal to nx, and the second When the film thickness of the resin layer is d (nm), it can be obtained from the above formula (1).

The second resin layer 22 may exhibit reverse dispersibility, but preferably exhibit positive dispersion because it is less likely to be deteriorated by ultraviolet rays than a layer exhibiting reverse dispersibility. Inverse dispersion is a characteristic in which the phase difference given to transmitted light increases as the wavelength of transmitted light increases. Specifically, retardation at a wavelength of 450 nm (Re450) and retardation at a wavelength of 550 nm (Re550). is a characteristic that satisfies Re450<Re550. On the other hand, the positive dispersion is a characteristic that satisfies Re450>Re550.

<<second ionizing radiation curable resin composition>>
The second ionizing radiation-curable resin composition is a resin composition that is cured by ionizing radiation, and contains at least an ionizing radiation-polymerizable compound that constitutes the resin contained in the liquid crystal compound and the cured product. However, the ionizing radiation-polymerizable compound may be an ionizing radiation-polymerizable liquid crystal, which will be described later. When the liquid crystal compound is not an ionizing radiation-polymerizable liquid crystal compound, it is necessary to further include an ionizing radiation-polymerizable compound in the second ionizing radiation-curable resin composition. may or may not contain an ionizing radiation-polymerizable compound in the second ionizing radiation-curable resin composition. The second ionizing radiation-curable resin composition may contain a polymerization initiator, a surfactant, a solvent, etc., in addition to the ionizing radiation-polymerizable compound.

<Liquid crystal compound>
Liquid crystal compounds include rod-like liquid crystal compounds such as nematic liquid crystal compounds and smectic liquid crystal compounds, cholesteric liquid crystal compounds, and discotic liquid crystal compounds. Among these, rod-like liquid crystal compounds and discotic liquid crystal compounds are preferred.

Further, the liquid crystal compound is preferably an ionizing radiation polymerizable liquid crystal compound. Since the liquid crystal compound is an ionizing radiation-polymerizable liquid crystal compound, the liquid crystal compound can be fixed in the second resin layer. The ionizing radiation-polymerizable liquid crystal compound is a liquid crystal compound having an ionizing radiation-polymerizable group, and examples thereof include monofunctional liquid crystal compounds having one ionizing radiation-polymerizable group and polyfunctional liquid crystal compounds having two or more polymerizable groups. Among these, polyfunctional liquid crystal compounds are preferred, polyfunctional liquid crystal compounds having 2 to 3 polymerizable groups are more preferred, and polyfunctional liquid crystal compounds having 2 polymerizable groups are even more preferred.

In the second resin layer 22, the liquid crystal compound is preferably fixed in any one of vertical alignment, horizontal alignment, hybrid alignment and tilt alignment. For example, it is preferable that the long axis of the rod-like liquid crystal compound is substantially horizontal with respect to the surface of the retardation layer. Further, it is preferable that the disk surface of the discotic liquid crystal compound is substantially perpendicular to the film surface (optically anisotropic layer surface).

The substantially horizontal rod-like liquid crystal compound means that the acute angle formed between the surface of the retardation layer and the director of the rod-like liquid crystal compound is in the range of 0° to 20°. 0° to 10° is more preferred, and 0° to 5° is even more preferred. Further, the discotic liquid crystal compound is substantially perpendicular means that the average value of the acute angles formed by the surface of the retardation layer and the discotic surface of the discotic liquid crystal compound is in the range of 70° to 90°. means. 80° to 90° is more preferred, and 85° to 90° is even more preferred.

Rod-shaped liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. As the rod-like liquid crystal compound, not only these low-molecular-weight liquid crystal compounds but also polymer liquid crystal compounds can be used. Moreover, it is preferable that the rod-like liquid crystal compound has a polymerizable group. The number of ionizing radiation-polymerizable groups in one molecule of the rod-like liquid crystal compound is preferably 2 to 3, more preferably 2.

Specific examples of rod-like liquid crystal compounds include compounds represented by the following chemical formulas (1) to (17).

Discotic liquid crystal compounds are described in various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., vol. 71, page 111 (1981); Chem., Chapter 5, Chapter 10, Section 2 (1994);B. Kohne et al., Angew.Chem.Soc.Chem.Comm., page 1794 (1985); Am.Chem.Soc., vol.116, page 2655 (1994)). The polymerization of the discotic liquid crystal compound is described in JP-A-8-27284.

The discotic liquid crystal compound preferably has an ionizing radiation polymerizable group. For example, a structure in which an ionizing radiation-polymerizable group is bonded as a substituent to the discotic core of a discotic liquid crystal compound can be considered. becomes difficult to keep. Therefore, a structure having a linking group between the discotic core and the ionizing radiation-polymerizable group is preferred. That is, the discotic liquid crystal compound having a polymerizable group is preferably a compound represented by the following formula.
D(-L-P) _n
wherein D is a discotic core, L is a divalent linking group, P is an ionizing radiation polymerizable group, and n is an integer from 1-12. Preferred specific examples of the discotic core (D), the divalent linking group (L) and the ionizing radiation polymerizable group (P) in the above formula are (D1) to (D15), (L1) to (L25), and (P1) to (P18), and the contents described in the publication can be preferably used. The phase transition temperature of the discotic liquid crystal compound is preferably 30° C. or higher and 300° C. or lower, more preferably 30° C. or higher and 170° C. or lower.

Further, as the liquid crystalline compound exhibiting reverse dispersion, JP-A-2010-537954, JP-A-2010-537955, JP-A-2010-522892, JP-A-2010-522893, and JP-A-2013- 509458 and other publications, and Japanese Patent No. 5892158, Japanese Patent No. 5979136, Japanese Patent No. 5994777, Japanese Patent No. 6015655, Japanese Patent No. 6055569, etc. Compounds or mixtures thereof are exemplified. be done. For example, Japanese Patent No. 6055569 discloses a mixture of a polymerizable liquid crystal compound represented by the following chemical formula (18) and a polymerizable liquid crystal compound represented by the following chemical formula (19).

A liquid crystal compound can be used individually by 1 type or in combination of 2 or more types. When one type is used alone, the one type of liquid crystal compound is preferably a polymerizable liquid crystal compound. When two or more are used in combination, at least one is preferably an ionizing radiation-polymerizable liquid crystal compound, and more preferably all are ionizing radiation-polymerizable liquid crystal compounds.

The content of the ionizing radiation-polymerizable liquid crystal compound in the first ionizing radiation-curable resin composition is 60% by mass or more and 99.9% by mass or less with respect to the total solid in the first ionizing radiation-curable resin composition. It is preferably 65% by mass or more and 98% by mass or less.

<Ionizing Radiation Polymerizable Compound>
As the ionizing radiation-polymerizable compound, the same ionizing radiation-polymerizable compound as described in the section of the first ionizing radiation-curable resin composition can be used, so description thereof will be omitted here.

<Polymerization initiator>
As the polymerization initiator, the same polymerization initiator as described in the section of the first ionizing radiation-curable resin composition can be used.

The content of the polymerization initiator is preferably 0.01% by mass or more and 20% by mass or less, and is 0.5% by mass or more and 5% by mass or less based on the total solid content of the first ionizing radiation-curable resin composition. is more preferable.

<Surfactant>
As the surfactant, it is preferable to select and use one or more selected from fluorine-based surfactants having ionizing radiation-polymerizable groups and silicon-based surfactants having ionizing radiation-polymerizable groups.

The content of the surfactant is preferably 0.01% by mass or more and 2.0% by mass or less, and 0.1% by mass or more and 1.0% by mass of the total solid content of the second ionizing radiation curable resin composition. % or less.

<Solvent>
The solvent is the same as the solvent described in the section of the second ionizing radiation-curable resin composition, so the description is omitted here.

The content of the solvent in the second ionizing radiation-curable resin composition is preferably 50% by mass or more and 90% by mass or less, and 70% by mass or more and 80% by mass or less in the second ionizing radiation-curable resin composition. It is more preferable to have

<<<Third Resin Layer>>>
The third resin layer 23 functions as an orientation layer for orienting the liquid crystal compound in the second ionizing radiation-curable resin composition in a predetermined direction when forming the second resin layer 22 . After forming the second resin layer 22, it may function as an optical adjustment layer. When the third resin layer 23 functions as an optical adjustment layer, the refractive index of the third resin layer 23 is adjusted to be between the refractive index of the first resin layer 21 and the refractive index of the second resin layer 22. do. By forming the third resin layer 23 having such a refractive index, reflection occurring at the interface between the first resin layer 21 and the second resin layer 22 can be reduced, and haze can be reduced.

The third resin layer 23 can be an orientation layer by applying a composition for the third resin layer on the first resin layer 21 and imparting an orientation regulating force. The composition for the third resin layer can be appropriately selected and used from conventionally known materials such as photodimerization type materials. Means for imparting an orientation regulating force to the third resin layer 23 can be conventionally known ones, and examples thereof include a rubbing method, a photo-alignment method, and a shaping method.

The film thickness of the third resin layer 23 is preferably 1 nm or more and 1000 nm or less. When the film thickness of the third resin layer 23 is 1 nm or more, the film can be formed. The lower limit of the film thickness of the third resin layer 23 is more preferably 5 nm or more, 10 nm or more, and 100 nm or more (the larger the value, the more preferable), and the upper limit is 900 nm or less, 800 nm or less, and 500 nm or less. preferable. The film thickness of the third resin layer is determined by photographing a cross section of the third resin layer using a scanning transmission electron microscope (STEM) or a transmission electron microscope (TEM), and measuring the thickness of the third resin layer in the image of the cross section. The thickness is measured at 10 points, and the arithmetic mean value of the thickness at 10 points is taken.

<<<release film>>>
The release film 30 is for transferring the polarizer protective film 20 to the polarizer described below by peeling it from the polarizer protective film 20 . The release film 30 may be light transmissive, but may not be light transmissive because the release film 30 is peeled off after the polarizer protective film 20 is transferred to the polarizer.

Although the thickness of the release film 30 is not particularly limited, it is preferably 25 μm or more and 100 μm or less. If the thickness of the release film is less than 25 μm, the effect of curing shrinkage of the first resin layer will be noticeable when the second ionizing radiation-curable resin composition is cured by ionizing radiation, and the release film is strong. Wrinkles are likely to occur, and if the thickness of the release film exceeds 100 μm, the manufacturing cost increases.

The release film 30 is not particularly limited, but is preferably a polyethylene terephthalate (PET) film. When the third resin layer 23 is formed, it is heated to about 100° C., so if a polyethylene film is used as the release film, heat shrinkage may occur. Therefore, there is no risk of heat shrinkage when the third resin layer 23 is formed. Moreover, the PET film is also excellent in smoothness.

Among PET films, a PET film having at least one side untreated is preferably used. In this case, the untreated side of the PET film is used as the release surface. A PET film having at least one untreated surface has excellent releasability from the first resin layer and is inexpensive, so that the manufacturing cost of the polarizer protective film transfer member 10 can be kept low. For example, when a release film coated with a silicon-containing Si-based release agent or the like is used as the release film, the release property of the release film is good, while the polarizer protective film At the time of the transfer, the components of the release agent may migrate to the side of the first resin layer, and the unevenness of the surface of the second resin layer may become large. On the other hand, if a PET film with at least one side untreated is used as the release film 30, there is no component transferred to the first resin layer 21 when the polarizer protective film is transferred, so the surface of the first resin layer 21 The unevenness of the surface of the first resin layer 21 is small, and the contact angle of water on the surface of the first resin layer 21 after transfer is less likely to change. As used herein, "a polyethylene terephthalate film untreated on at least one side" means a PET film having an untreated side. Therefore, the untreated surface of the PET film having at least one untreated surface does not have a release agent for enhancing the releasability.

As the release film 30, a PET film having one surface untreated and the other surface having a base layer is more preferable. Such a PET film has the above-described effects, and the base layer functions as an antiblocking layer. Sticking between 10 can be suppressed.

[Method for producing a polarizer protective film and a transfer body for a polarizer protective film]
The polarizer protective film transfer member 10 and the polarizer protective film 20 can be produced, for example, as follows. First, the first ionizing radiation curable resin composition is applied to one surface 30A of the release film 30, dried, and the first ionizing radiation curable resin composition is applied as shown in FIG. A membrane 24 is formed.

The method of applying the first ionizing radiation curable resin composition is not particularly limited, and examples include spin coating, dipping, spraying, die coating, bar coating, roll coating, meniscus coating, flexographic printing, Known methods such as a screen printing method and a speed coater method can be used.

Next, as shown in FIG. 2B, the coating film 24 is cured by irradiating the coating film 24 with ionizing radiation such as ultraviolet rays to cure the first ionizing radiation-curable resin composition. Thereby, the first resin layer 21 is formed.

After forming the first resin layer 21, the surface of the second resin layer 22 is coated with the composition for the third layer and dried to obtain the composition for the third resin layer as shown in FIG. A coating film 25 is formed.

Next, as shown in FIG. 3B, the coating film 25 is heated at a temperature of 60° C. or more and 150° C. or less to cure the coating film 25 . Thereby, the third resin layer 23 is formed.

After forming the third resin layer 23, the surface of the third resin layer 23 is coated with the second ionizing radiation-curable resin composition, dried, and cured by the second ionizing radiation as shown in FIG. A coating film 26 of a flexible resin composition is formed.

Next, as shown in FIG. 4B, the coating film 26 is cured by irradiating the coating film 26 with ionizing radiation such as ultraviolet rays to cure the second ionizing radiation-curable resin composition. Thereby, the second resin layer 22 is formed, and the polarizer protective film transfer member 10 shown in FIG. 1 is obtained.

When the polarizer protective film 20 alone is obtained from the polarizer protective film transfer member 10, the release film 30 is peeled off from the polarizer protective film 20 as shown in FIG. 4(C). The release film 30 is preferably peeled off with the polarizer protective film transfer body 10 attached to the polarizer.

[Polarizing plate and image display device]
The image display device 40 shown in FIG. 5 includes a display element 50, a circularly polarizing plate 60, a touch sensor 70, and a cover member 80 in this order facing the observer. The display element 50 and the circularly polarizing plate 60, the circularly polarizing plate 60 and the touch sensor 70, and the touch sensor 70 and the cover member 80 are adhered via adhesive layers 91-93. "Adhesion" as used herein is a concept including adhesion.

<<<display element>>>
Examples of the display element 50 include liquid crystal elements, organic light emitting diode elements (hereinafter also referred to as "OLED elements"), inorganic light emitting diode elements, micro LEDs, plasma elements, and the like. A known organic light emitting diode element can be used as the organic light emitting diode element. Further, the liquid crystal display element may be an in-cell touch panel liquid crystal display element having a touch panel function inside the element.

When the display element 50 is a light-emitting element such as an OLED element, the emission peak wavelength of blue light of the light-emitting element is λ1, the absorption start wavelength of the first resin layer 21 is λ2, and the absorption start wavelength of the second resin layer 22 is λ2. When λ3, it is preferable to satisfy the relationship of λ1>λ2>λ3. By satisfying such a relationship, the image display device 40 can suppress absorption of blue light emitted from the light emitting element and suppress deterioration of the second resin layer 22 due to ultraviolet rays.

The emission wavelength λ1 of the display element 50 can be measured using a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta, Inc.) at a measurement angle of 1°. Further, when obtaining the absorption start wavelength λ2 of the first resin layer 21 and the absorption start wavelength λ3 of the second resin layer 23, first, a color filter spectral characteristic measuring device (device name “LCF-100MA-SF”, Otsuka Electronics (manufactured by Co., Ltd.), the transmission spectrum of each layer is measured in a wavelength range of 380 nm to 480 nm with a halogen lamp light source and a spot diameter of 2 μm, and the inclination of the transmission spectrum is obtained in increments of 10 nm wavelength. Then, the wavelength at which the slope drops sharply when viewed from the perspective of the slope data is found, and this wavelength is taken as the absorption start wavelength.

<<<circularly polarizing plate>>>
The circularly polarizing plate 60 has a function of cutting external light. The circularly polarizing plate 60 includes, for example, a first retardation film 61 (hereinafter sometimes simply referred to as “retardation film 61”), an adhesive layer 62, and a second retardation film facing the viewer side. 63 (hereinafter sometimes simply referred to as “retardation film 63”), adhesive layer 64, polarizer protective film 65, polarizer 66, adhesive layer 67, and polarizer protective film 20, Prepared in order.

In the circularly polarizing plate 60 , the second resin layer 22 of the polarizer protective film 20 is located closer to the polarizer 66 than the first resin layer 21 is. By arranging the polarizer protective film 20 in this way, the first resin layer 21 can suppress deterioration of the second resin layer by ultraviolet rays.

The thickness of the circularly polarizing plate 60 is preferably 250 μm or less from the viewpoint of thinning. The lower limit of the thickness of the circularly polarizing plate 60 is preferably 25 μm or more, 30 μm or more, or 35 μm or more from the viewpoint of workability due to strength reduction (the larger the value, the more preferable). Moreover, the upper limit of the thickness of the circularly polarizing plate 60 is preferably 250 μm or less, 200 μm or less, or 150 μm or less (the smaller the value, the better). The thickness of the circularly polarizing plate 60 is obtained by photographing a cross section of the circularly polarizing plate 60 using a scanning electron microscope (SEM), measuring the thickness of the circularly polarizing plate 60 at 10 locations in the image of the cross section, and measuring the thickness of the 10 locations. It can be obtained by calculating the arithmetic mean value of the film thickness.

The circularly polarizing plate 60 has a spectral transmittance of less than 1% at a wavelength of 380 nm and a spectral transmittance of 0.5% or more at a wavelength of 410 nm for the same reason as described in the section on the polarizer protective film 20. It is preferable that it is less than 30% and that the spectral transmittance at a wavelength of 440 nm is 35% or more. The lower limit of the spectral transmittance of the circularly polarizing plate 60 at a wavelength of 410 nm is more preferably 1% or more, and the upper limit is more preferably 25% or less. More preferably, the lower limit of the spectral transmittance of the circularly polarizing plate 60 at a wavelength of 440 nm is 40% or more and 45% or more (the larger the value, the more preferable). The spectral transmittance of the circularly polarizing plate 60 at a wavelength of 380 nm or the like is measured in the same manner as the spectral transmittance of the polarizer protective film 20 at a wavelength of 380 nm or the like.

For the same reason as explained in the column of the polarizer protective film 20, the circularly polarizing plate 60 preferably has a spectral transmittance of 5% or more and 25% or less at a wavelength of 420 nm. The spectral transmittance at a wavelength of 420 nm in the circularly polarizing plate 60 is also measured in the same manner as the spectral transmittance at a wavelength of 380 nm.

The circularly polarizing plate 60 preferably has a yellow index (YI) of 15 or less for the same reason as described in the section on the polarizer protective film 20 . The lower limit of YI is originally preferably lower from the viewpoint of ensuring high transparency, but considering that blue light cut performance is also given, it is more preferably 1 or more, 2 or more, or 3 or more (the numerical value is preferably larger). However, if YI is too large, yellowishness may become stronger. Therefore, the upper limit of YI is more preferably 10 or less, 7 or less, or 6 or less (the smaller the number, the better). The YI of the circularly polarizing plate 60 is measured in the same manner as the YI of the polarizer protective film 20 .

The reason explained in the column of the polarizer protective film 20 when the circular polarizing plate 60 was subjected to a mandrel test according to JIS K5600-5-1: 1999 (a test in which a sample was wound around a metal cylinder of 2 mm to 32 mm). For the same reason as above, it is preferable that the minimum diameter of the cylinder is 6 mm or less when cracks do not occur in the circularly polarizing plate 60 . The mandrel test of the circularly polarizing plate 60 shall be measured in the same manner as the mandrel test of the polarizer protective film 20 .

When the circularly polarizing plate 60 is attached to another film via an adhesive layer or an adhesive layer, the other film is peeled off by the same method as described in the section of the polarizer protective film 20. , spectral transmittance, YI measurement and mandrel test shall be performed. Even if there is such a peeling process, it does not greatly affect each measurement.

<<First Retardation Film>>
As the retardation film 61, a positive C plate or a λ/4 retardation film can be used.

<Positive C plate>
A positive C plate is a film that satisfies the relationship nx≈ny<nz, where nx and ny are refractive indices in the in-plane direction and nz is the refractive index in the thickness direction. By arranging the positive C plate, it is possible to improve the color when viewed from a direction oblique to the normal direction of the display screen. A positive C-plate may, for example, consist of a vertically aligned liquid crystal layer.

<λ/4 retardation film>
A λ/4 retardation film is a film having a property that the in-plane retardation of the film is about 1/4 with respect to a predetermined wavelength of light (usually in the visible light region). By arranging the λ/4 retardation film, linearly polarized light can be converted into circularly polarized light, or circularly polarized light can be converted into linearly polarized light.

The λ/4 retardation film includes a λ/4 retardation film having positive wavelength dispersion and a λ/4 retardation film having negative wavelength dispersion. λ / 4 retardation film having a 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 a negative wavelength dispersion becomes a longer wavelength. The film has the property of increasing the retardation.

A 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. A λ/4 retardation film having negative wavelength dispersion can be obtained, for example, from a polycarbonate-based resin or a resin having an aromatic structure.

<<adhesion layer>>
The adhesive layers 62, 64, 67 are composed of a cured product of a liquid ionizing radiation-curable adhesive (eg, OCR: Optical Clear Resin) containing an ionizing radiation polymerizable compound and an adhesive (eg, OCA: Optical Clear Adhesive). It is possible to The film thickness of the adhesive layers 62, 64, 67 is preferably 0.5 μm or more and 50 μm or less.

<<Second Retardation Film>>
When the retardation film 61 is a positive C plate, as the retardation film 63, a λ / 4 retardation film having negative wavelength dispersion (reverse wavelength dispersion) can be used, and the retardation film If 61 is a λ/4 retardation film, a λ/2 retardation film can be used.

<λ/4 retardation film having negative wavelength dispersion>
The λ / 4 retardation film having a negative wavelength dispersion is the same as the λ / 4 retardation film having a negative wavelength dispersion described in the section of the λ / 4 retardation film, so it is described here. shall be omitted.

<λ/2 retardation film>
A λ/2 retardation film is a film having a property that the in-plane retardation of the film is about 1/2 with respect to a predetermined wavelength of light (usually in the visible light region). By arranging the λ/2 retardation film in addition to the λ/4 retardation film, it is possible to convert into circularly polarized light in a wide wavelength band.

A λ/2 retardation film 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/2 retardation film include polycarbonate-based resins and cycloolefin-based resins.

<<polarizer protective film>>
The polarizer protective film 65 is for protecting the polarizer 66 . The thickness of the polarizer protective film 65 is preferably 5 μm or more and 80 μm or less. The thickness of the polarizer protective film 65 is obtained by photographing a cross section of the polarizer protective film 65 using a scanning electron microscope (SEM), measuring the thickness of the polarizer protective film 65 at 10 locations in the cross-sectional image, and measuring the thickness of the polarizer protective film 65. It can be obtained by calculating the arithmetic mean value of only 10 films.

The protective film 65 is preferably made of resin. Examples of resins include polyester-based resins, acetylcellulose-based resins, cycloolefin-based resins, polyethersulfone-based resins, polycarbonate-based resins, polyolefin-based resins, (meth)acrylic-based resins, polyvinyl chloride-based resins, and polyvinylidene chloride. resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, polyphenylene sulfide resins, and the like. Among these, (meth)acrylic resins are preferable from the viewpoint of low water vapor permeability and suppression of deterioration of OLED elements due to moisture, since OLED elements are easily deteriorated even by moisture. Various additives such as a plasticizer, an ultraviolet absorber, and a lubricating agent may be added to these light-transmitting substrates, if necessary.

Examples of polyester-based resins include resins containing at least one of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polybutylene naphthalate (PBN) as a constituent component. It is known that when a polyester base material is used, it has the property of being excited by ultraviolet light and emitting fluorescence. Since such fluorescence may affect the color of the display surface, it is preferable to block light with a wavelength of 380 nm or less as described above when using a polyester-based resin. As a result, even if a polyester-based resin is used as the resin, it is possible to suitably prevent fluorescence from occurring.

Acetylcellulose resins include, for example, triacetylcellulose resins and diacetylcellulose resins. Triacetyl cellulose-based resin is a base material capable of having an average light transmittance of 50% or more in the visible light range of 380 to 780 nm. The average light transmittance of the triacetylcellulose base material is preferably 70% or more, more preferably 85% or more.

In addition to pure triacetyl cellulose, the triacetyl cellulose-based resin may be a product in which a component other than acetic acid is also used as a fatty acid that forms an ester with cellulose, such as cellulose acetate propionate and cellulose acetate butyrate. good. Moreover, other cellulose lower fatty acid esters such as diacetyl cellulose may be added to these triacetyl celluloses, if necessary.

Examples of cycloolefin-based resins include substrates made of polymers such as norbornene-based monomers and monocyclic cycloolefin monomers. Examples of commercially available cycloolefin resins include Zeonex and Zeonor (norbornene resin) manufactured by Nippon Zeon Co., Ltd., Sumilite FS-1700 manufactured by Sumitomo Bakelite Co., Ltd., and ARTON (modified norbornene resin) manufactured by JSR Corporation. , Mitsui Chemicals Co., Ltd. APEL (cyclic olefin copolymer), Ticona Co. Topas (cyclic olefin copolymer), Hitachi Chemical Co., Ltd. Optoretsu OZ-1000 series (alicyclic acrylic resin), etc. mentioned.

Examples of polycarbonate-based resins include aromatic polycarbonate-based resins based on bisphenols (such as bisphenol A) and aliphatic polycarbonate-based resins such as diethylene glycol bisallyl carbonate.

Examples of (meth)acrylic resins include polymethyl(meth)acrylate resins, polyethyl(meth)acrylate resins, methyl (meth)acrylate-butyl(meth)acrylate copolymer resins, and the like. mentioned.

<<Polarizer>>
A polarizer 66 is arranged between the polarizer protective films 20 , 65 . The polarizer protective film 20 is preferably arranged such that the angle between the slow axis of the polarizer protective film 20 and the absorption axis of the polarizer 66 is 30° or more and 60° or less. By arranging the polarizer protective film 20 at such an angle, high transmitted light can be obtained regardless of the angle of the polarized sunglasses. More preferably, the angle between the slow axis of the polarizer protective film 20 and the absorption axis of the polarizer 66 is 40° or more and 50° or less.

When transferring the polarizer protective film 20 to the polarizer 66, for example, after the polarizer 66 is attached to the polarizer protective film 65, the polarizer protective film transfer body 10 is applied to the polarizer 66 by ionizing radiation. Paste through a curable adhesive. Then, the release film 30 is peeled off.

The polarizer 66 may be a polyvinyl alcohol resin film dyed with iodine or a dichroic dye and uniaxially stretched. As the polyvinyl alcohol-based resin, a saponified polyvinyl acetate-based resin can be used. Polyvinyl acetate-based resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate with other monomers copolymerizable therewith. Other monomers copolymerizable with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used.

<<<Touch sensor>>>
A known touch sensor can be used as the touch sensor 70 . Although the type of the touch sensor 70 is not particularly limited, for example, a capacitive touch sensor can be used. The touch sensor 70 is arranged between the circularly polarizing plate and the cover member, but may be arranged between the display element 50 and the circularly polarizing plate 60 .

<<<cover material>>>
A surface 80A of the cover member 80 serves as a surface 40A of the image display device 40 . The cover member 80 may be a cover glass or a cover film made of resin. When the image display device 40 has flexibility, the cover member 80 is preferably made of flexible glass or flexible resin. Examples of flexible resins include polyimide-based resins, polyamide-imide-based resins, polyamide-based resins, polyester-based resins (e.g., polyethylene terephthalate resins and polyethylene naphthalate resins), and mixtures of two or more of these resins. is mentioned.

<<<adhesive layer>>>
The adhesive layers 91 to 93 are composed of a cured product of a liquid ionizing radiation curable adhesive (eg, OCR: Optical Clear Resin) containing an ionizing radiation polymerizable compound, or an adhesive (eg, OCA: Optical Clear Adhesive). is possible.

From the viewpoint of thinning the image display device 40, the thickness of the adhesive layers 91 to 93 is preferably 0.5 μm or more and 50 μm or less. For the thickness of the adhesive layers 91 to 93, a scanning electron microscope (SEM) is used to photograph the cross section of the adhesive layers 91 to 93, and the thickness of the adhesive layers 91 to 93 is measured at 10 points in the image of the cross section. It can be obtained by calculating the arithmetic mean value of only 10 films.

According to this embodiment, the polarizer protective film 20 does not have a base material, so it can be made thinner.

In the case of an image display device equipped with a polarizer, the emitted light from the image display device becomes linearly polarized light. Therefore, when an observer observes the display screen of the image display device through polarized sunglasses, depending on the viewing angle, the display may be significantly different. The screen may become dark and visibility may be reduced. In contrast, according to the present embodiment, the second resin layer 22 contains a liquid crystal compound, so that the second resin layer 22 can function as a λ/4 retardation layer. As a result, the linearly polarized light transmitted through the polarizer 66 can be changed into circularly polarized light, so that even when the displayed image is observed through polarized sunglasses, the deterioration of visibility can be suppressed.

EXAMPLES In order to describe the present invention in detail, examples are given below, but the present invention is not limited to these descriptions. In addition, "parts" and "%" in the text are based on mass unless otherwise specified.

<Preparation of first ionizing radiation curable resin composition>
A first ionizing radiation-curable resin composition was obtained by blending each component so as to have the composition shown below.
(First ionizing radiation curable resin composition 1)
6-[5-(2-Hydroxyethyl)-2H-benzotriazol-2-yl]benzo[1,3]dioxole-5 was added to a 200 mL 4-necked flask equipped with a ball condenser, mercury thermometer, and stirrer. - Add 4.0 g (0.013 mol) of ol, 40 mL of toluene, 1.8 g (0.021 mol) of methacrylic acid, and 0.4 g (0.004 mol) of methanesulfonic acid, at 110-115° C. for 4 hours. Dehydrated at reflux. Then, 30 mL of water and 0.6 g (0.006 mol) of sodium carbonate were added, the mixture was allowed to stand, and the lower aqueous layer was separated and removed. After filtration, 40 mL of toluene is recovered from the filtrate under reduced pressure, 100 mL of isopropyl alcohol is added, the precipitated crystals are filtered, washed with 40 mL of isopropyl alcohol, and dried at 40° C. under reduced pressure to obtain yellow crystals. .2 g. 4.2 g of this yellow crystal was repulp washed with isopropyl alcohol and dried at 40° C. under reduced pressure to give 3.4 g of 2-[2-(6-hydroxybenzo[1,3] as a sesamol-type benzotriazole compound. Dioxol-5-yl)-2H-benzotriazol-5-yl]ethyl methacrylate was obtained.

Then, a four-necked flask was equipped with a Dimroth condenser, a mercury thermometer, a nitrogen gas inlet tube, and a stirrer, and the synthesized 2-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H was synthesized. -8 parts by weight of benzotriazol-5-yl]ethyl methacrylate, 32 parts by weight of methyl methacrylate (MMA) as another monomer, 20 parts by weight of toluene as a solvent, 20 parts by weight of methyl ethyl ketone, and a polymerization initiator 0.6 parts by mass of 1,1′-azobis(cyclohexane-1-carbonitrile) is added, and the inside of the flask is replaced with nitrogen at a nitrogen gas flow rate of 10 mL / min for 1 hour while stirring. After that, the reaction liquid temperature is 90 to 96. The polymerization reaction was carried out in a reflux state at ℃ for 10 hours.

After completion of the polymerization reaction, 10 parts by mass of toluene and 10 parts by mass of methyl ethyl ketone (MEK) were added, and 100.6 parts by mass of a solution containing acrylic polymer 1 as an ultraviolet absorber in which a sesamol-type benzotriazole-based compound was reactively bonded to MMA. got

A mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (product name “KAYARAD PET-30”, manufactured by Nippon Kayaku Co., Ltd.) and the above acrylic polymer 1 were mixed at a solid content mass ratio of 20:80, and the solid content was mixed to 25%. A resin composition was prepared by diluting with a solvent (mass ratio of methyl ethyl ketone and toluene: 80:20).

Then, with respect to 160 parts by mass of the resulting resin composition, 4 parts by mass of a polymerization initiator (mass ratio of Omnirad 184 and Omnirad 819 manufactured by IGM Resins B.V. 50:50) and a leveling agent (product name "F568" , manufactured by DIC Corporation) and 0.2 parts by mass were mixed and thoroughly stirred to prepare a first ionizing radiation-curable resin composition 1.

(First ionizing radiation curable resin composition 2)
A resin composition was prepared by diluting urethane acrylate (product name “UV-3310B”, manufactured by The Nippon Synthetic Chemical Industry Co., Ltd.) with methyl ethyl ketone to a solid content of 25%. Then, with respect to 120 parts by mass of the resulting resin composition, 4 parts by mass of a polymerization initiator (mass ratio of Omnirad 184 and Omnirad 819 manufactured by IGM Resins B.V. 50:50), an indole compound as an ultraviolet absorber ( Product name "BONASORB UA-3912", manufactured by Orient Chemical Industry Co., Ltd.) 3 parts by mass, and benzotriazole compound (product name "JF-79", manufactured by Johoku Chemical Co., Ltd.) 5 parts by mass, leveling agent (product name "F568 ", manufactured by DIC Corporation) was mixed and thoroughly stirred to prepare a first ionizing radiation-curable resin composition 2.

(First ionizing radiation curable resin composition 3)
50 parts by mass of dicyclopentenyl acrylate (product name “FA-511AS”, manufactured by Hitachi Chemical Co., Ltd.), a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (product name “KAYARAD PET-30”), which are ionizing radiation polymerizable compounds , Nippon Kayaku Co., Ltd.) 50 parts by mass, a polymerization initiator (product name "Omnirad 184", manufactured by IGM Resins B.V.) 4 parts by mass, and a leveling agent (product name "F568", manufactured by DIC Corporation) 0.2 parts by mass were mixed, a solvent (methyl isobutyl ketone) was added to the mixture, and the mixture was stirred to prepare a first ionizing radiation-curable resin composition 3 having a solid concentration of 25%.

<Preparation of second ionizing radiation curable resin composition>
A second ionizing radiation-curable resin composition was obtained by blending each component so as to have the composition shown below.
(Second ionizing radiation curable resin composition 1)
Liquid crystal compound represented by the above chemical formula (11): 20 parts by mass Polymerization initiator (product name "Omnirad 184", manufactured by IGM Resins B.V.): 5 parts by mass Fluorosurfactant (product name " Megafac F477", manufactured by DIC Corporation): 0.4 parts by mass Mixed solvent (MEK: NMP = 1: 1): 74.6 parts by mass

(Second ionizing radiation curable resin composition 2)
0.99 g of the liquid crystal compound represented by the above chemical formula (18) and 10 mg of the liquid crystal compound represented by the above chemical formula (19) were dissolved in a mixed solvent of 0.3 g of 1,3-dioxolane and 2.0 g of cyclopentanone. , to obtain mixture 1. Then, a second ionizing radiation-curable resin composition 2 was obtained by blending each component so as to have the composition shown below.
・Mixture 1: 20 parts by mass ・Polymerization initiator (product name “Omnirad 184”, manufactured by IGM Resins B.V.): 5 parts by mass ・Fluorine-based surfactant (product name “Megafac F477”, manufactured by DIC Corporation ): 0.4 parts by mass Mixed solvent (MEK: NMP = 1: 1): 74.6 parts by mass

<Ionizing Radiation Curable Adhesive Composition 1>
An ionizing radiation-curable adhesive composition 1 was obtained by blending each component so as to have the composition shown below.
・ Hydroxyacrylamide (product name “HEAA”, manufactured by KJ Chemicals): 40 parts by mass ・ Tripropylene glycol diacrylate (product name “M-220”, manufactured by Toagosei Co., Ltd.): 20 parts by mass ・ Acryloylmorpholine (product name “ ACMO", manufactured by KJ Chemicals): 40 parts by mass Polymerization initiator (product name "Irgacure 819", manufactured by BASF Japan): 1.4 parts by mass

<Example 1>
First, prepare a polyethylene terephthalate film (PET film, product name “Cosmo Shine A4100”, manufactured by Toyobo Co., Ltd.) with a thickness of 100 μm and one side of which is easy to adhere as a release film. The first ionizing radiation curable resin composition 1 was applied to form a coating film. Next, dry air at 50° C. is passed through the formed coating film at a flow rate of 0.5 m/s for 15 seconds, and then dry air at 70° C. is passed at a flow rate of 10 m/s for 30 seconds to dry. The solvent in the coating film was evaporated by heating, and the coating film was cured by irradiating the coating film with ultraviolet rays so that the integrated light amount was 200 mJ/cm ² . Thus, a hard coat layer as a first resin layer having a thickness of 8 μm was formed.

After forming the hard coat layer, an alignment film-forming composition containing a polycinnamate-based compound (4% solids, diluted with propylene glycol monomethyl ether) was applied onto the first resin layer to form a coating film. The resulting coating film was dried at 120° C. for 1 minute and irradiated with polarized light at 20 mJ/cm ² (310 nm) to form an alignment film as a third layer having a thickness of 200 nm.

Next, the second ionizing radiation-curable resin composition 1 was applied onto the alignment film with a bar coater and dried to form a coating film. Next, dry air at 120°C was passed through the formed coating film for 60 seconds to dry it, thereby evaporating the ^solvent in the coating film. to cure the coating. Thus, a λ/4 retardation layer was formed as the second resin layer with a film thickness of 2.0 μm. As a result, a transfer member for a polarizer protective film comprising a polarizer protective film and a release film having a thickness of 10.2 μm was obtained.

The film thickness of the first resin layer is obtained by photographing a cross section of the first resin layer using a scanning transmission electron microscope (STEM), measuring the film thickness of the first resin layer at 10 locations in the image of the cross section, and measuring the thickness of the first resin layer. The arithmetic mean value of the film thickness at 10 locations was used. A specific method for taking cross-sectional photographs will be described below. First, a block was prepared by embedding a polarizer protective film cut into a size of 1 mm×10 mm in an embedding resin, and a uniform section having a thickness of 70 nm or more and 100 nm or less without holes was prepared from the block by a general section preparation method. cut out. "Ultramicrotome EM UC7" (Leica Microsystems, Inc.) was used to prepare the sections. Then, this uniform section without holes or the like was used as a measurement sample. After that, using a scanning transmission electron microscope (STEM) (product name “S-4800”, manufactured by Hitachi High-Technologies Corporation), a cross-sectional photograph of the measurement sample was taken. When the cross-sectional photograph is taken, the cross-sectional observation is performed with the detector set to "TE", the acceleration voltage set to 30 kV, and the emission set to "10 .mu.A." Magnification was appropriately adjusted between 5,000 and 200,000 times while adjusting the focus and observing whether each layer could be distinguished in terms of contrast and brightness. When taking a cross-sectional photograph, the aperture is set to 3 for the beam monitor diaphragm, the objective lens diaphragm is set to 3, and the W.F. D. was set to 8 mm. The film thicknesses of the second resin layer and the third resin layer were also measured in the same manner as the film thickness of the first resin layer.

On the other hand, a polarizer is produced by adsorbing iodine onto a polyvinyl alcohol-based film and then uniaxially stretching and orienting it, and a polyvinyl alcohol-based adhesive (polyvinyl alcohol resin (product name: PVA -117” (manufactured by Kuraray Co., Ltd.) diluted with pure water to a solid content of 5%) was applied. Then, the polarizer and the polarized light were placed so that one surface of the polarizer was in contact with a polarizer protective film made of a saponified 25 μm-thick triacetyl cellulose base (product name “TJ25UL”, manufactured by FUJIFILM Corporation). Placed a protective film. In this state, it was dried at 100° C. for 10 minutes to obtain an intermediate in which the polarizer and the polarizer protective film were bonded together with a polyvinyl alcohol-based adhesive.

After obtaining the intermediate, the ionizing radiation curable adhesive 1 is applied to the other surface of the polarizer, and the λ / 4 retardation layer is applied from above to the ionizing radiation curable adhesive so that the polarizer protective film Placed the transcript. The polarizer protective film transfer member was arranged so that the angle formed by the absorption axis of the polarizer and the slow axis of the λ/4 retardation layer was 45°. In this state, the ionizing radiation-curable adhesive was cured by irradiating ultraviolet light from the side of the polarizer protective film made of the TAC base material so that the cumulative light amount was 200 mJ/cm ² . As a result, the intermediate and the transfer member for a polarizer protective film were bonded together.

Then, the release film PET film was peeled off from the polarizer protective film transfer body to obtain a polarizing plate with the hard coat layer exposed on the surface.

After obtaining the polarizing plate, an adhesive layer (product name “Panaclean (registered trademark) PD-S1” manufactured by Panac Co., Ltd.) is applied to the surface of the polarizing plate on the side of the polarizer protective film made of the TAC base material, A λ/2 retardation film was attached. The λ / 2 retardation film is a 100 μm thick cycloolefin resin film (product name “Zeonor ZF-14”, manufactured by Zeon Corporation) at 150 ° C. so that the in-plane retardation at a wavelength of 550 nm is 270 nm. obtained by stretching at Furthermore, on the surface opposite to the polarizing plate side surface of the λ / 2 retardation film, an adhesive layer (product name “Panaclean (registered trademark) PD-S1”, manufactured by Panac Co., Ltd.) is placed through the λ / 4 A retardation film was laminated. A circularly polarizing plate was thus obtained. The λ / 4 retardation film is a 100 μm thick cycloolefin resin film (product name “Zeonor ZF-14”, manufactured by Nippon Zeon Co., Ltd.) at a wavelength of 550 nm. obtained by stretching at

After obtaining the circularly polarizing plate, an adhesive layer (product name "Panaclean (registered trademark) PD- S1", manufactured by Panac Co., Ltd.), an organic light emitting diode panel (OLED panel) containing an organic light emitting diode element taken out from an organic EL display (product name "Galaxy SII", manufactured by Samsung) was bonded. As a result, an image display device was obtained in which the OLED panel, the adhesive layer, and the circularly polarizing plate were laminated in this order facing the observer.

<Example 2>
In Example 2, a polarizer protective film, a polarizer protective film, and a A polarizer protective film transfer member, a circularly polarizing plate and an image display device were obtained.

<Example 3>
In Example 3, a polarizer protective film, a polarizer protective film, and a A polarizer protective film transfer member, a circularly polarizing plate and an image display device were obtained.

<Example 4>
In Example 4, a polarizer protective film, a polarizer protective film, and a A polarizer protective film transfer member, a circularly polarizing plate and an image display device were obtained.

<Comparative Example 1>
In Comparative Example 1, a circularly polarizing plate and an image display device were obtained in the same manner as in Example 1, except that the polarizer protective film on the observer's side was composed of a cycloolefin polymer base material and a hard coat layer. .

A polarizer protective film according to Comparative Example 1 was formed as follows. First, a 100 μm-thick cycloolefin resin film (product name “Zeonor ZF-14”, manufactured by Nippon Zeon Co., Ltd.) was stretched at 150° C. so that the in-plane retardation at a wavelength of 550 nm was 140 nm. A cycloolefin polymer substrate (COP substrate) having a thickness of 25 μm was obtained. Then, the first ionizing radiation-curable resin composition 3 was applied to one surface of this COP substrate to form a coating film. Next, dry air at 50° C. is passed through the formed coating film at a flow rate of 0.5 m/s for 15 seconds, and then dry air at 70° C. is passed at a flow rate of 10 m/s for 30 seconds to dry. The solvent in the coating film was evaporated by heating, and the coating film was cured by irradiating the coating film with ultraviolet rays so that the integrated light amount was 200 mJ/cm ² . Thereby, a hard coat layer having a thickness of 5 μm was formed to obtain a polarizer protective film.

<Comparative Example 2>
In Comparative Example 2, a polarizer protective film, a polarizer protective film transfer body, and a circularly polarizing plate were prepared in the same manner as in Example 1, except that the polarizer protective film on the viewer side was composed only of the hard coat layer. And an image display device was obtained.

A polarizer protective film according to Comparative Example 2 was formed as follows. First, prepare a polyethylene terephthalate film (PET film, product name “Cosmo Shine A4100”, manufactured by Toyobo Co., Ltd.) with a thickness of 100 μm and one side of which is easy to adhere as a release film. The first ionizing radiation curable resin composition 1 was applied to form a coating film. Next, dry air at 50° C. is passed through the formed coating film at a flow rate of 0.5 m/s for 15 seconds, and then dry air at 70° C. is passed at a flow rate of 10 m/s for 30 seconds to dry. The solvent in the coating film was evaporated by heating, and the coating film was cured by irradiating the coating film with ultraviolet rays so that the integrated light amount was 200 mJ/cm ² . Thus, a hard coat layer having a thickness of 10 μm was formed to obtain a polarizer protective film.

<Phase difference value measurement>
Retardation values of the polarizer protective films according to Examples and Comparative Examples were measured. Specifically, first, an adhesive layer (product name “Panaclean (registered trademark) PD-S1”, Panac Co., Ltd.) is attached to an optically isotropic glass (length 30 mm × width 30 mm, thickness 1 mm). , and the polarizer protective film transfer member were laminated together so that the λ/4 retardation layer was in contact with the adhesive layer. After that, the PET film was peeled off from the polarizer protective film to expose the hard coat layer to obtain a measurement sample. A polarizer protective film transfer member used as a measurement sample was cut from the central portion of the polarizer protective film transfer member into a size of 40 mm long×40 mm wide. Then, the in-plane retardation (retardation) of this measurement sample at a wavelength of 589 nm was measured using a phase difference measuring device (product name "KOBRA-WR", manufactured by Oji Scientific Instruments Co., Ltd., measurement spot: diameter 5 mm).

<Measurement of emission wavelength of OLED panel>
The emission wavelength λ1 of the OLED panels used in Examples and Comparative Examples was measured. The emission wavelength of the OLED panel was measured using a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta, Inc.) at a measurement angle of 1°.

<Measurement of absorption start wavelength of hard coat layer and λ/4 retardation layer>
The absorption start wavelength λ2 of the hard coat layer and the absorption start wavelength λ3 of the λ/4 retardation layer in the polarizer protective films according to Examples and Comparative Examples were measured. Specifically, first, using a color filter spectral characteristic measurement device (device name “LCF-100MA-SF”, manufactured by Otsuka Electronics Co., Ltd.), a spot diameter of 2 μm and a halogen lamp light source of 380 nm or more and 480 nm or less of each layer. The transmission spectrum in the wavelength range was measured, and the inclination of the transmission spectrum was determined at wavelength intervals of 10 nm. Then, when looking at the data of the slope from a broader perspective, the wavelength at which the slope drops sharply was found, and this wavelength was used as the absorption start wavelength.

<Indentation hardness (H _IT )>
The indentation hardness of the λ/4 retardation layer and the hard coat layer of the circularly polarizing plate of the example was measured. That is, the indentation hardness (H _IT ) was measured using a TI950 TriboIndenter manufactured by HYSITRON. Specifically, first, a block was prepared by embedding a circularly polarizing plate cut into a size of 1 mm×10 mm with an embedding resin to prepare a measurement sample suitable for hardness measurement by the nanoindentation method. An “Ultramicrotome EM UC7” (Leica Microsystems, Inc.) was used to prepare a sample for measurement. Next, the measurement sample was fixed to the stage of TI950 TriboIndenter manufactured by HYSITRON so that the surface of the measurement sample into which the indenter is pushed was parallel to the mounting surface of the stage. Then, a Berkovich type indenter is applied to the flat part in the center of the cross section of the λ / 4 retardation layer by a load control method at a load rate of 10 μN / sec, and a load is applied from 0 μN to 300 μN in 30 seconds. The layer was pushed into the cross-sectional center, held at 300 μN for 5 seconds, and then unloaded from 300 μN to 0 μN in 30 seconds. Then, the indentation depth h (nm) corresponding to the indentation load F (N) at this time was continuously measured to create a load-displacement curve. From the created load-displacement curve, the indentation hardness H _IT , the maximum indentation load F _max (N) as in the above formula (2), and the projected area A _p where the indenter and the λ / 4 retardation layer are in contact It was obtained by dividing by (mm ² ). The indentation hardness was taken as the arithmetic mean value of the values obtained by measuring 10 points. Note that A _p was a value determined by the above formula (3). The indentation hardness of the hard coat layer was also measured under the same conditions as those of the λ/4 retardation layer.

<Visibility evaluation>
Visibility was evaluated before and after the light resistance test in the image display devices according to Examples and Comparative Examples. Specifically, first, in a dark place, the image display device before the light resistance test is displayed in white, and the angle formed by the absorption axis of the polarized sunglasses and the absorption axis of the polarizer is from 0° (parallel Nicols) to 90°. It was evaluated whether or not the displayed image could be visually recognized by rotating it so as to be (crossed nicols). After that, using a light resistance tester (product name "UV fade meter U48AU", manufactured by Suga Test Instruments Co., Ltd.), light from a carbon arc lamp was applied to the image display device at 42 ° C. and a relative humidity of 50%. A light fastness test was carried out by irradiating for a period of time. Then, again, in a dark place, in the image display device after the light fastness test, it was evaluated whether or not the displayed image could be visually recognized under the same conditions as above. The evaluation criteria were as follows.
⊚: The displayed image could be viewed at any angle (compatible with polarized sunglasses).
◯: Visibility was slightly lowered depending on the angle, but it was at a level of no problem in practical use.
x: Depending on the angle, the displayed image could not be visually recognized (not compatible with polarized sunglasses).

<Flexibility>
A mandrel test (a test in which a sample is wound around a metal cylinder of 2 mm to 32 mm) was performed on the circularly polarizing plates of Examples to evaluate the flexibility. Specifically, a circular polarizing plate cut into a size of 50 mm × 50 mm is subjected to a mandrel test according to JIS K5600-5-1: 1999, and the circular polarizing plate is cut so that the second resin layer is on the inside. was wound around a cylinder, and the minimum diameter of the cylinder was determined so that no cracks occurred in the circularly polarizing plate. The evaluation results were as follows.
○: The minimum diameter was 6 mm or less.
x: The minimum diameter exceeded 6 mm.

The results are shown in Table 1 below.

As shown in Table 1, the observer-side polarizer protective film according to Comparative Example 1 was thick because it had a COP substrate. On the other hand, the polarizer protective films according to Examples 1 to 4 were thin because they did not have a substrate.

As shown in Table 1, the viewer-side polarizer protective film according to Comparative Example 2 did not include a λ/4 retardation layer containing a liquid crystal compound, so visibility through polarized sunglasses was poor. . On the other hand, the image display devices according to Examples 1 to 4 had a λ/4 retardation layer containing a liquid crystal compound, and therefore had excellent visibility through polarized sunglasses.

The visibility through polarized sunglasses after the light resistance test in the image display device according to Example 1 was superior to the visibility through polarized sunglasses after the light resistance test in the image display device according to Example 3. This is because the hard coat layer of the polarizer protective film according to Example 1 contained an ultraviolet absorber, so that ultraviolet deterioration of the liquid crystal compound in the λ/4 retardation layer could be suppressed.

DESCRIPTION OF SYMBOLS 10... Transfer body for polarizer protective film 20... Polarizer protective film 21... First resin layer 22... Second resin layer 23... Third resin layer 30... Release film 40... Image display device 50... Display element 60... Circle Polarizer

Claims (5)

a display element, a polarizing plate provided with a polarizer, and a polarizer protective film attached to the polarizer and positioned closer to the viewer than the polarizer; An image display device comprising
The polarizer protective film is a substrate-less polarizer protective film,
The polarizer protective film comprises a first resin layer containing a cured product of a first ionizing radiation curable resin composition, and a second ionizing resin layer disposed on one side of the first resin layer and containing at least a liquid crystal compound. and a second resin layer containing a cured product of the radiation curable resin composition,
The indentation hardness of the first resin layer is greater than the indentation hardness of the second resin layer,
The indentation hardness of the first resin layer is 100 MPa or more and 600 MPa or less,
The first resin layer contains an ultraviolet absorber,
the second resin layer is positioned closer to the polarizer than the first resin layer,
When the display element is a light-emitting element, the emission peak wavelength of blue light of the light-emitting element is λ1, the absorption start wavelength of the first resin layer is λ2, and the absorption start wavelength of the second resin layer is λ3. , λ1>λ2>λ3. 2. The image display device according to claim 1, wherein the film thickness of said second resin layer is 0.1 [mu]m or more and 10 [mu]m or less. 3. The image display device according to claim 1, wherein the polarizer protective film has an in-plane retardation of 80 nm or more and 220 nm or less at a wavelength of 589 nm. The image display device according to any one of claims 1 to 3, wherein the polarizer protective film has a thickness of 20 µm or less. 2. The image display device according to claim 1 , wherein said display elements are organic light emitting diodes.

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