Anisotropic light-diffusing film, film for display using same, and display

Abstract

This anisotropic light-diffusing film (3) has an anisotropic light-diffusing layer (30) formed by photopolymerization of a composition comprising a photopolymerizable compound, a photopolymerization initiator, and a thermoplastic elastomer having a glass transition temperature no higher than 0°C. The anisotropic light-diffusing layer (30) has a matrix region (31) and a columnar region (32) formed from multiple columnar structures (33) having refractive indices different from that of the matrix region (31).

Description

Anisotropic light-diffusing film, and display film and display using the same

[0001] The present invention relates to an anisotropic light-diffusing film and a display film and a display using the same. This application claims priority based on Japanese Patent Application No. 2024-73986, filed on April 30, 2024, the contents of which are incorporated herein by reference.

[0002] Anisotropic light diffusion films are effective in improving the viewing angle, brightness, and image quality in the display field, and are also used as window films to provide transparent screens and maintain privacy.

[0003] However, as the brightness of displays continues to improve, it has been pointed out that this increases eye strain and may lead to a decrease in eyesight. Therefore, attempts have been made to reduce eye strain by using anti-glare (AG) films on the display surface to suppress strong brightness in the front direction and further reduce the reflectance of external light. However, in the case of high-resolution displays, the size of the unevenness of the AG film can cause pixel mixing, resulting in glare such as scintillation due to interference, as well as a decrease in contrast. Regarding this issue, Patent Document 1 discloses an anti-glare film that can suppress a decrease in contrast while eliminating scintillation by combining an anti-glare layer with an anisotropic light-diffusing layer.

[0004] On the other hand, there has been recent talk of expanding the use of anisotropic light-diffusing films to curved displays or windows. In this regard, the required performance of anisotropic light-diffusing films is that they do not develop defects such as cracks or wrinkles even when used in a curved state in low to high temperature environments.

[0005] Under such circumstances, Patent Document 2 proposes a light diffusion control film in which the relationship between the storage modulus and the loss modulus is specified in order to improve the flexibility at 5°C.

[0006] However, in recent years, the requirements for low-temperature environments have become even stricter, and there is a risk that a sufficient effect against bending may not be obtained at an even lower temperature (-15°C).In addition, there is a risk that a sufficient effect against bending may not be obtained even at a high temperature of 60°C.

[0007] International Publication No. 2018 / 180541 Japanese Patent Application Laid-Open No. 2019-144418

[0008] The present invention provides an anisotropic light-diffusing film that does not develop defects such as cracks or wrinkles even when used at temperatures from -15°C to 60°C in displays that require bending or in curved windows, and a display film and display using the same.

[0009] The present invention includes the following aspects: [1] An anisotropic light-diffusing film having an anisotropic light-diffusing layer formed by photopolymerization of a composition containing a photopolymerizable compound, a photopolymerization initiator, and a thermoplastic elastomer having a glass transition temperature of 0°C or lower, wherein the anisotropic light-diffusing layer has a matrix region and a columnar region composed of a plurality of columnar structures having a refractive index different from that of the matrix region. [2] The anisotropic light-diffusing layer has a storage modulus of 1.0 × 10 at −15°C. ７ Pa ~ 2.0 x 10 ９ Pa and loss modulus of 1.0 × 10 ７ Pa ~ 2.0 x 10 ９ Pa, and the storage modulus of the anisotropic light-diffusing layer at 25° C. is 1.0×10 ７ Pa ~ 2.0 x 10 ９ Pa and loss modulus of 1.0 × 10 ７ Pa ~ 2.0 x 10 ９ Pa, and the storage modulus of the anisotropic light-diffusing layer at 60° C. is 1.0×10 ６ Pa ~ 2.0 x 10 ８ Pa and loss modulus of 1.0 × 10 ６ Pa ~ 2.0 x 10 ８[3] The anisotropic light-diffusing film according to [1], characterized in that the loss tangent of the anisotropic light-diffusing layer at -15°C to 60°C is 0.07 to 0.8. [4] The anisotropic light-diffusing film according to any one of [1] to [3], characterized in that the peak temperature on the lowest temperature side of the loss tangent of the anisotropic light-diffusing layer is 0°C or less. [5] The anisotropic light-diffusing film according to any one of [1] to [4], characterized in that the blending ratio of the thermoplastic elastomer is 30% or less of the entire composition. [6] The anisotropic light-diffusing film according to any one of [1] to [5], characterized in that the linear transmittance at an incident light angle of 0° is 1% or more and less than 20%, the linear transmittance at an incident light angle of 15° is 1% or more and less than 20%, and the linear transmittance at an incident light angle of 45° is 30% or more and less than 80%. [7] The anisotropic light-diffusing film according to any one of [1] to [6], wherein the aspect ratio of the cross section perpendicular to the column axis direction of the column structure is less than 2. [8] The anisotropic light-diffusing film according to any one of [1] to [6], wherein the aspect ratio of the cross section perpendicular to the column axis direction of the column structure is 2 to 40. [9] The anisotropic light-diffusing film according to any one of [1] to [8], wherein the anisotropic light-diffusing layer has a thickness of 10 μm to 60 μm.

[10] The anisotropic light-diffusing film according to any one of [1] to [9], wherein the thermoplastic elastomer is a photocurable compound.

[11] The anisotropic light-diffusing film according to any one of [1] to [9], wherein the thermoplastic elastomer is a thermosetting compound, the composition further contains a curing agent, and the anisotropic light-diffusing layer is formed by photopolymerization and thermal polymerization, which is the photopolymerization plus thermal polymerization.

[12] A film for display, comprising the anisotropic light-diffusing film according to any one of [1] to

[11] and an antiglare layer on the viewing side of the anisotropic light-diffusing layer.

[13] The film for display according to

[12] , wherein the arithmetic mean roughness of the antiglare layer is 0.05 μm to 1.00 μm.

[14] A display comprising the film for a display according to

[12] or

[13] , with the antiglare layer positioned on the most visible side.

[0010] According to the present invention, it is possible to provide an anisotropic light-diffusing film that does not develop abnormalities such as cracks or wrinkles even when used at temperatures from -15°C to 60°C in a display that requires bending or in a curved window, a display film using the same, and a display using the same.

[0011] Fig. 1 is a schematic cross-sectional view showing one embodiment of the anisotropic light-diffusing film of the present invention. Fig. 2 is a schematic cross-sectional view showing one embodiment of the film for display of the present invention. Fig. 3 is a schematic cross-sectional view showing another example of the film for display of the present invention. Fig. 4 is a schematic cross-sectional view showing another example of the film for display of the present invention. Fig. 5 is a schematic view showing a first example of a method for producing an anisotropic light-diffusing film of the present invention, which includes optional steps 1-3. Fig. 6 is a schematic view showing a second example of a method for producing an anisotropic light-diffusing film of the present invention, which includes optional steps 1-3. Fig. 7 is an explanatory view showing a method for evaluating the linear transmittance of an anisotropic light-diffusing layer.

[0012] The meanings of key terms used in this specification and claims are as follows:

[0013] The "anisotropic light diffusion layer" is a light diffusion layer that has incident light angle dependency, and the diffusibility changes depending on the incident light angle, i.e., the linear transmittance changes depending on the incident light angle.

[0014] The "anisotropic light-diffusing film" refers to a film mainly comprising an anisotropic light-diffusing layer, and may further comprise other layers (e.g., an adhesive layer, a functional layer, a transparent film layer, etc.) in addition to the anisotropic light-diffusing layer. Alternatively, the film may comprise a single layer of anisotropic light-diffusing layer.

[0015] "Linear transmittance" is the ratio of the amount of light transmitted in a linear direction (linear transmitted light amount) to the amount of incident light (incident light amount) when light is incident on an anisotropic light-diffusing film (anisotropic light-diffusing layer) at a certain incident light angle, and is expressed by the following formula. The linear direction refers to the direction in which the incident light travels. The linear transmitted light amount can be measured by the method described in paragraph 0157 of JP 2015-191178 A or in the examples of this specification. Linear transmittance (%) = (linear transmitted light amount / incident light amount) x 100

[0016] The "maximum linear transmittance" is the linear transmittance of light incident at an incident light angle at which the linear transmittance is maximum.

[0017] The "minimum linear transmittance" is the linear transmittance of light incident at an incident light angle at which the linear transmittance is minimum.

[0018] The "scattering central axis" refers to the direction that coincides with the angle of incident light of light at which the light diffusion properties are approximately symmetrical across the angle of incident light when the angle of incident light to the anisotropic light-diffusing layer is changed. The reason for the term "approximately symmetrical" is that if the scattering central axis is tilted with respect to the normal direction of the anisotropic light-diffusing layer, the optical characteristics (the "optical profile" described below) will not strictly be symmetrical. The scattering central axis can be confirmed from the incident light angle at which the optical profile is approximately symmetrical.

[0019] The "optical profile" refers to a curve obtained by graphing the linear transmittance values ​​of an anisotropic light diffusion layer when the angle of incidence of light is changed. Although the optical profile does not directly express light diffusion properties, if we interpret it as meaning that a decrease in linear transmittance conversely increases diffuse transmittance, it can be said that it generally indicates the dependency of light diffusion on the angle of incidence. The incident light angle at the approximate center between the minimum values ​​in the optical profile is the scattering central axis angle.

[0020] In the present invention, "scattering" and "diffusion" have the same meaning.

[0021] "Photopolymerization" and "photocuring" both mean that a photopolymerizable compound undergoes a polymerization reaction due to light.

[0022] By (meth)acrylate, it is meant that it can be either an acrylate or a methacrylate.

[0023] [Anisotropic Light-Diffusing Film and Display Film Using the Same] The anisotropic light-diffusing film of the present invention and a display film using the same will be described with reference to the accompanying drawings. Fig. 1 is a schematic cross-sectional view showing an example of an anisotropic light-diffusing film 3 according to one embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing an example of a display film 10 according to one embodiment of the present invention.

[0024] The anisotropic light-diffusing film 3 of this embodiment can be used not only in display films 10 but also in curved windows, etc. The present invention provides an anisotropic light-diffusing film 3 that does not develop defects such as cracks or wrinkles even when used at temperatures from -15°C to 60°C in displays that require bending or curved windows, etc. For this reason, in the anisotropic light-diffusing film 3 of the present invention, the anisotropic light-diffusing layer 30 contains a thermoplastic elastomer having a glass transition temperature of 0°C or lower.

[0025] The display film 10 of this embodiment includes an antiglare layer 1 and an anisotropic light-diffusing film 3. The antiglare layer 1 is disposed on the viewing side of the anisotropic light-diffusing layer in the anisotropic light-diffusing film 3. Optionally, a light-transmitting substrate 5 and a transparent adhesive layer 7 are further provided between the antiglare layer 1 and the anisotropic light-diffusing film 3. The first surface 1a of the antiglare layer 1 is an uneven surface. A light-transmitting substrate 5, a transparent adhesive layer 7, and an anisotropic light-diffusing film 3 are sequentially laminated on a second surface 1b of the antiglare layer 1 opposite the first surface 1a. The display film 10 typically includes an antiglare layer laminate 9 in which the antiglare layer 1 is formed on one surface of the light-transmitting substrate 5, and an anisotropic light-diffusing film 3 laminated together via the transparent adhesive layer 7. However, the configuration of the display film of the present invention is not limited to this configuration.

[0026] 1 is a schematic cross-sectional view showing an example of an anisotropic light-diffusing film 3 according to one embodiment of the present invention, which is composed of a single-layer anisotropic light-diffusing layer 30. The anisotropic light-diffusing film 3 may be composed of only the anisotropic light-diffusing layer 30, or may have layers other than the anisotropic light-diffusing layer 30 (for example, an adhesive layer, a functional layer, a transparent film layer, etc.).

[0027] The anisotropic light-diffusing layer 30 has a matrix region 31 and a columnar region 32 composed of a plurality of columnar structures 33 having a refractive index different from that of the matrix region 31. Each of the plurality of columnar structures 33 extends from one surface side to the other surface side of the anisotropic light-diffusing layer 30. One end of the columnar structure 33 reaches one surface of the anisotropic light-diffusing layer 30. The other end of the columnar structure 33 may or may not reach the other surface of the anisotropic light-diffusing layer 30. Neither end of the columnar structure 33 may reach the surface of the anisotropic light-diffusing layer 30. In this example, the extending direction of the columnar structures 33 coincides with the thickness direction (normal direction) of the anisotropic light-diffusing layer 30. However, the anisotropic light-diffusing layer 30 is not limited to this, and may be inclined with respect to the thickness direction of the anisotropic light-diffusing layer 30.

[0028] The refractive index of the matrix region 31 may be different from the refractive index of the columnar structures 33, but the degree of difference is not particularly limited and is relative. When the refractive index of the matrix region 31 is lower than that of the columnar structures 33, the matrix region 31 becomes a low-refractive index region. Conversely, when the refractive index of the matrix region 31 is higher than that of the columnar structures 33, the matrix region 31 becomes a high-refractive index region. Here, it is preferable that the refractive index at the interface between the matrix region 31 and the columnar structures 33 gradually changes. By gradually changing the refractive index, the change in light diffusion when the angle of incident light is changed becomes extremely steep, making it less likely that scintillation will occur. By forming the matrix region 31 and the columnar structures 33 by phase separation due to light irradiation, the refractive index at the interface between the matrix region 31 and the columnar structures 33 can be gradually changed.

[0029] The average height H of the columnar structures 33 in the thickness direction of the anisotropic light-diffusing layer 30 is 80% or more of the thickness T of the anisotropic light-diffusing layer 30, preferably 90% or more, and more preferably 95% or more. When the ratio of the average height H to the thickness T is equal to or greater than the above-mentioned lower limit, the front contrast is less likely to decrease. When the ratio of the average height H to the thickness T is equal to or greater than the above-mentioned lower limit, the interface between the matrix region 31 and the columnar structures 33 exists continuously and without interruption over a certain range or more in the thickness direction of the anisotropic light-diffusing layer 30, so that light incident from a direction oblique to the scattering central axis of the anisotropic light-diffusing layer 30 is less likely to be scattered. The upper limit of the average height H to the thickness T is not particularly limited, but is preferably 100%.

[0030] The average height H of the columnar structures 33 can be determined by using an optical microscope to measure the heights of 20 columnar structures 33 and averaging the measured heights. The height of the columnar structures 33 refers to the height from the bottom to the top of the columnar structures 33 when the anisotropic light-diffusing layer 30 is placed horizontally with one surface of the anisotropic light-diffusing layer 30 facing downward and the other surface facing upward.

[0031] There is no particular limitation on the cross-sectional shape perpendicular to the extending direction of the columnar structures 33. For example, the cross-sectional shape may be a circle, an ellipse, a polygon, an irregular shape, or a mixture of these.

[0032] The length of the cross-sectional shape perpendicular to the extension direction (column axis direction) of the columnar structure 33 is expressed using the minor axis, major axis, or diameter. When the cross-sectional shape is circular, the diameter of the circle is referred to as the diameter, not the minor axis and major axis. When the cross-sectional shape is elliptical, the length of the minor axis is referred to as the minor axis, and the length of the major axis is referred to as the major axis. When the cross-sectional shape is polygonal or irregular, the length between the shortest two points on the outline of these shapes is referred to as the minor axis, and the length between the longest two points is referred to as the major axis.

[0033] When the average minor axis or diameter of the 20 columnar structures 33 is SA and the average major axis or diameter of the 20 columnar structures 33 is LA, the aspect ratio (LA / SA), which is the ratio of LA to SA, may be less than 2, more preferably less than 1.5, and even more preferably less than 1.2, in the case of a pillar structure in which the columnar structures are rod-shaped. The lower limit of the aspect ratio is 1. In other words, LA and SA may have the same value. When the aspect ratio is less than 2, the effect of suppressing a decrease in front contrast is more excellent. In the case of a louver structure in which the columnar structures are plate-shaped, the aspect ratio may be 2 to 40.

[0034] The length of LA is at least equal to or greater than the length of SA, and is preferably equal to or greater than 0.5 μm, more preferably equal to or greater than 1.0 μm, and even more preferably equal to or greater than 1.5 μm. Setting LA to the above-mentioned value or greater tends to broaden the diffusion range. LA is preferably equal to or less than 8.0 μm, more preferably equal to or less than 3.0 μm, and even more preferably equal to or less than 2.5 μm. Setting LA to the above-mentioned value or less tends to result in a gentle change in diffusivity when the incident light angle is changed, thereby better preventing the occurrence of scintillation and light interference (rainbow). These lower and upper limits of LA can be appropriately combined. For example, setting LA of the columnar structure 33 to 0.5 μm to 8.0 μm broadens the diffusion range, and the change in diffusivity when the incident light angle is changed becomes more gentle, which tends to further suppress the occurrence of scintillation and light interference.

[0035] The length of SA is at least equal to or shorter than the length of LA, and is preferably equal to or greater than 0.5 μm, more preferably equal to or greater than 1.0 μm, and even more preferably equal to or greater than 1.5 μm. When SA is equal to or greater than the above value, the light diffusion and light collection properties tend to be better. SA is preferably equal to or less than 5.0 μm, more preferably equal to or less than 3.0 μm, and even more preferably equal to or less than 2.5 μm. When the minor axis SA is equal to or less than the above value, the diffusion range tends to be wider. These lower and upper limits of SA can be appropriately combined. For example, by setting the SA of the columnar structures 33 to 0.5 μm to 5.0 μm, the diffusion range tends to be wider, and the light diffusion and light collection properties tend to be better.

[0036] The cross-sectional shape perpendicular to the extension direction of the columnar structures 33 can be confirmed by observing the surface of the anisotropic light-diffusing layer 30 with an optical microscope. LA and SA can be determined by observing the surface of the anisotropic light-diffusing layer 30 with an optical microscope, measuring the major axis, minor axis, or diameter of the cross-sectional shape of 20 arbitrarily selected columnar structures 33, and averaging the respective values. The aspect ratio is determined by dividing the above-determined LA by SA.

[0037] The anisotropic light-diffusing layer 30 has a central scattering axis. When a plurality of columnar regions 32 each consisting of a plurality of columnar structures 33 are present in the plane direction of the anisotropic light-diffusing layer 30 (for example, when adjacent columnar regions 32 are separated only by matrix regions 31 that do not include columnar structures 33), the central scattering axis can be defined for each columnar region 32. When a plurality of columnar structures 33 are distributed throughout the anisotropic light-diffusing layer 30, it is also possible to define a single central scattering axis for the entire anisotropic light-diffusing layer 30.

[0038] In the columnar region 32 of the anisotropic light-diffusing layer 30, each of the plurality of columnar structures 33 is formed so that the extending direction of the columnar structure 33 is parallel to the scattering central axis of the columnar region 32. The extending direction of the columnar structure 33 and the scattering central axis of the columnar region 32 being parallel only needs to satisfy the law of refractive index (Snell's law), and do not need to be strictly parallel. Snell's law states that the refractive index n １ The refractive index n ２ When light is incident on the interface of the medium, the incident light angle θ １ and the refraction angle θ ２ Between １ sinθ １ = n ２ sinθ ２ For example, the following relationship holds: １ = 1 (air), n ２ = 1.51 (anisotropic light diffusion layer), when the incident light angle (scattering central axis angle) is 30°, the extension direction (refractive angle) of the columnar structures 33 is approximately 19°. However, even if the incident light angle and the refraction angle differ in this way, as long as they satisfy Snell's law, they are included in the concept of parallelism in this embodiment.

[0039] Light incident on the anisotropic light-diffusing layer 30 at a predetermined incident light angle is preferentially diffused when the incident light angle is approximately parallel to the extension direction (orientation direction) of the columnar structures 33, and is preferentially transmitted when the incident light angle is not approximately parallel to the extension direction. Therefore, when the angle of light incident on the anisotropic light-diffusing layer 30 changes, the linear transmittance also changes. Specifically, in the anisotropic light-diffusing layer 30, incident light is strongly diffused within an incident light angle range close to the extension direction of the columnar structures 33 (diffusion region), but diffusion is weakened and linear transmittance increases within other incident light angle ranges (non-diffusion region).

[0040] The scattering central axis angle of the anisotropic light-diffusing layer 30 is preferably −45° to +45°, more preferably −40° to +40°, and even more preferably −35° to +35°. The scattering central axis angle is the polar angle θ formed between the normal to the anisotropic light-diffusing layer 30 and the scattering central axis. If the scattering central axis angle is within the above range, the contrast will be better.

[0041] The positive and negative angles of the scattering central axis are defined as positive (+) when the scattering central axis is tilted to one side with respect to a plane passing through both a predetermined axis of symmetry in the plane direction of the anisotropic light-diffusing layer 30 and the normal direction of the anisotropic light-diffusing layer 30, and negative (-) when the scattering central axis is tilted to the other side. Here, the predetermined axis of symmetry is, for example, the MD (Machine Direction) passing through the center of gravity of the anisotropic light-diffusing layer 30. In the present invention, the MD is the coating direction in producing the anisotropic light-diffusing layer.

[0042] The scattering central axis angle, i.e., the polar angle θ, is measured using a goniophotometer. The scattering central axis angle can be adjusted to a desired angle by changing the direction of the light irradiated onto the sheet-shaped photocurable resin composition layer (composition layer for anisotropic light-diffusing film) during production of the anisotropic light-diffusing layer 30.

[0043] The anisotropic light-diffusing film 3 preferably has a linear transmittance of 1% or more and less than 20% at an incident light angle of 0°, a linear transmittance of 1% or more and less than 20% at an incident light angle of 15°, and more preferably a linear transmittance of 30% or more and less than 80% at an incident light angle of 45°. By setting the linear transmittance of the anisotropic light-diffusing film 3 to fall within the above ranges (preferably satisfying the two numerical ranges for linear transmittance at incident light angles of 0° and 15°, and more preferably satisfying the three numerical ranges for linear transmittance at incident light angles of 0°, 15°, and 45°), the anisotropic light-diffusing film 3 has better scintillation prevention performance and contrast.

[0044] The present invention provides an anisotropic light-diffusing film 3 that does not develop defects such as cracks or wrinkles even when used at temperatures between -15°C and 60°C in displays that require bending, curved windows, etc. For this reason, the loss tangent of the anisotropic light-diffusing layer 30 at temperatures between -15°C and 60°C is preferably 0.07 to 0.8. By setting the loss tangent within this range, the anisotropic light-diffusing film 3 tends to be more effectively prevented from developing defects such as cracks or wrinkles even when used at temperatures between -15°C and 60°C in displays that require bending, curved windows, etc.

[0045] The loss tangent (tan δ), along with the storage modulus (E′) and loss modulus (E″), can be measured by dynamic mechanical analysis (DMA).

[0046] The storage modulus and loss modulus of the anisotropic light-diffusing layer 30 at −15° C. to 60° C. may be, for example, in the following ranges: ７ Pa ~ 2.0 x 10 ９ Pa and loss modulus of 1.0 × 10 ７ Pa ~ 2.0 x 10 ９ The storage modulus of the anisotropic light-diffusing layer 30 at 25° C. is preferably 1.0×10 ７ Pa ~ 2.0 x 10 ９ Pa and loss modulus of 1.0 × 10 ７ Pa ~ 2.0 x 10 ９The storage modulus of the anisotropic light-diffusing layer 30 at 60° C. is preferably 1.0×10 ６ Pa ~ 2.0 x 10 ８ Pa and loss modulus of 1.0 × 10 ６ Pa ~ 2.0 x 10 ８ Pa is preferred.

[0047] By setting the storage modulus of the anisotropic light-diffusing layer 30 within the above range, the occurrence of cracks in the anisotropic light-diffusing film 3 tends to be further suppressed even when used in a display that requires bending, a curved window, etc. at temperatures between −15° C. and 60° C. Furthermore, by setting the loss modulus of the anisotropic light-diffusing layer 30 within the above range, the occurrence of wrinkles in the anisotropic light-diffusing film 3 tends to be further suppressed even when used in a display that requires bending, a curved window, etc.

[0048] The lowest temperature peak temperature of the loss tangent of the anisotropic light-diffusing layer 30 is preferably 0° C. or lower, more preferably −10° C. or lower, and even more preferably −30° C. or lower. By setting the loss tangent of the anisotropic light-diffusing layer 30 within the above range, the occurrence of cracks in the anisotropic light-diffusing film 3 tends to be further suppressed even when the film is used at 0° C. or lower in a display that requires bending or a curved window, for example.

[0049] The anisotropic light-diffusing layer 30 is typically made of a cured product of a composition containing a photopolymerizable compound. When the layer of this composition is cured, regions with different refractive indices are formed. The composition containing the photopolymerizable compound will be described in detail later.

[0050] The thickness of the anisotropic light-diffusing film 3 is preferably 10 μm to 60 μm. If the thickness is equal to or greater than the lower limit, the anisotropic light-diffusing film 3 is less likely to tear. If the thickness is equal to or less than the upper limit, the anisotropic light-diffusing film 3 is more likely to bend. The thickness is measured, for example, by a method including the following steps (1) to (3): (1) A cross section of the film is formed using a microtome, and this cross section is observed under an optical microscope. (2) On the cross section, the length between one surface of the film and its opposite surface in a direction perpendicular to the film plane (thickness direction) is measured at 10 points. (3) The average value of the measurements obtained at the 10 points is defined as the thickness of the anisotropic light-diffusing film 3.

[0051] (Antiglare Layer) The antiglare layer 1 may be any layer as long as the first surface 1a is an uneven surface, and may be appropriately selected from known antiglare layers. An example of the antiglare layer 1 is a layer containing a transparent resin. The total light transmittance (JIS K 7361-1:1997) of the transparent resin is preferably 80% or more, more preferably 90% or more. Examples of transparent resins include thermoplastic resins and cured products of curable resins. Examples of curable resins include thermosetting resins and photocurable resins.

[0052] Examples of thermoplastic resins used as the transparent resin of the antiglare layer 1 include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), cycloolefin copolymer (COC), norbornene-containing resins, and polyethersulfone.

[0053] Examples of thermosetting resins used as the transparent resin in the antiglare layer 1 include phenol resins, furan resins, xylene-formaldehyde resins, ketone-formaldehyde resins, urea resins, melamine resins, aniline resins, alkyd resins, unsaturated polyester resins, and epoxy resins. These may be used alone or in combination.

[0054] Examples of the photocurable resin used as the transparent resin in the antiglare layer 1 include a monomer, oligomer, or prepolymer having a radically polymerizable functional group such as an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group, or a cationically polymerizable functional group such as an epoxy group, a vinyl ether group, or an oxetane group, either alone or in combination.

[0055] Examples of monomers for photocurable resins include methyl acrylate, methyl methacrylate, methoxypolyethylene methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, ethylene glycol dimethacrylate, didipentaerythritol hexaacrylate, trimethylolpropane trimethacrylate, urethane acrylate, etc. These can be used alone or in combination.

[0056] Examples of photocurable resin oligomers and prepolymers include acrylate compounds such as polyester acrylate, polyurethane acrylate, multifunctional urethane acrylate, epoxy acrylate, polyether acrylate, alkyd acrylate, melamine acrylate, and silicone acrylate, unsaturated polyester, epoxy compounds such as tetramethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether, and various alicyclic epoxies, and oxetane compounds such as 3-ethyl-3-hydroxymethyloxetane, 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene, and di[1-ethyl(3-oxetanyl)]methyl ether. These can be used alone or in combination.

[0057] When the photocurable resin is photocured by ultraviolet irradiation, a photopolymerization initiator is blended into the photocurable resin, and the photocurable resin composition containing the photopolymerization initiator is used. The light used for photocuring may be ultraviolet light, visible light, or infrared light. The light may be polarized or unpolarized.

[0058] As the photopolymerization initiator, radical polymerization initiators such as acetophenones, benzophenones, thioxanthones, benzoin, and benzoin methyl ether, and cationic polymerization initiators such as aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, and metallocene compounds can be used alone or in appropriate combination.

[0059] The photocurable resin composition may further contain a polymer resin to the extent that the polymeric curing of the photocurable resin is not hindered. This polymer resin is typically a thermoplastic resin, and specific examples thereof include acrylic resin, alkyd resin, and polyester resin. These resins preferably have an acidic functional group such as a carboxyl group, a phosphoric acid group, or a sulfonic acid group.

[0060] When forming an antiglare layer using a photocurable resin composition, a coating material containing the photocurable resin composition and an organic solvent may be used. This coating material is applied, the organic solvent is volatilized, and then the layer is photocured by irradiating light, thereby forming a layer containing a transparent resin. The organic solvent is appropriately selected from those suitable for dissolving the photocurable resin composition. Specifically, a single or mixed solvent selected from alcohols, esters, ketones, ethers, and aromatic hydrocarbons can be used, taking into consideration coating suitability such as wettability to the translucent substrate, viscosity, and drying speed.

[0061] Particles may be dispersed in the transparent resin. The particle size is not limited as long as it can form an uneven surface on the first surface 1a of the antiglare layer 1. Furthermore, by using particles (scattering particles) made of a material with a refractive index different from that of the transparent resin, it is possible to impart internal scattering properties to the antiglare layer 1. Note that the method for forming an uneven surface on the first surface 1a of the antiglare layer 1 is not limited to the method using particles, and known methods such as embossing can also be used. Examples of particles include cross-linked polymer particles of methyl methacrylate or polystyrene, silica particles, etc.

[0062] Additives may be added to the transparent resin. Examples of additives include leveling agents, ultraviolet (UV) absorbers, antistatic agents, thickeners, etc. The leveling agent functions to equalize the tension of the coating film surface formed from a coating material containing a transparent resin or its precursor (such as a curable resin) and an organic solvent, and to repair defects before the antiglare layer is formed. A substance having lower interfacial tension and surface tension than the transparent resin or its precursor is used. The thickener functions to impart thixotropy to the coating material, and has the effect of preventing the settling of particles, etc., and facilitating the formation of fine irregularities on the surface of the antiglare layer.

[0063] The arithmetic mean roughness (Ra) of the first surface 1a (concave-convex surface) of the antiglare layer 1 is preferably 0.05 μm to 1.00 μm, more preferably 0.10 μm to 0.80 μm, and even more preferably 0.15 μm to 0.50 μm. When Ra is equal to or greater than the lower limit, the antiglare properties are superior. When Ra is equal to or less than the upper limit, the haze of the display film 10 is low, resulting in better image clarity. Ra is measured in accordance with JIS B0601:2013.

[0064] The internal haze of the antiglare layer 1 is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. The internal haze is caused by internal scattering in the antiglare layer 1. When the internal haze is equal to or less than the upper limit, the image clarity, black brightness, and contrast are superior. The internal haze is measured using a haze meter in accordance with JIS K7136-1:2000.

[0065] The internal haze of the antiglare layer 1 can be adjusted, for example, by the content of scattering particles (particles whose refractive index differs by 0.03 or more from that of the matrix (the resin constituting the layer)) in the antiglare layer 1, the type of scattering particles, etc. The lower the content of scattering particles or the smaller the difference between the refractive index of the scattering particles and that of the matrix, the smaller the internal haze tends to be. The content of scattering particles in the antiglare layer 1 is preferably 30 parts by weight or less, and may be 0 part by weight, relative to the resin constituting the layer.

[0066] The thickness of the antiglare layer 1 is preferably 1 to 25 μm, more preferably 2 to 10 μm, and even more preferably 3 to 7 μm. When the thickness of the antiglare layer 1 is equal to or greater than the lower limit, the antiglare properties are superior. Furthermore, when the antiglare layer 1 is a layer formed from a photocurable resin composition, a thickness of the antiglare layer 1 equal to or greater than the lower limit makes it less likely for poor curing to occur during photocuring, and the antiglare layer 1 has excellent abrasion resistance. When the thickness of the antiglare layer 1 is equal to or less than the upper limit, the image clarity is superior. Furthermore, when the antiglare layer 1 is a layer formed from a photocurable resin composition, problems due to cure shrinkage (such as curling, microcracks, and reduced adhesion to the translucent substrate) are less likely to occur. Furthermore, it is possible to suppress cost increases due to the increase in the amount of paint required as the film thickness increases.

[0067] (Light-Transmitting Substrate) The light-transmitting substrate 5 functions as a support for the anti-glare layer 1. The higher the transparency of the light-transmitting substrate 5, the more preferable. The total light transmittance of the light-transmitting substrate 5 is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The total light transmittance of the light-transmitting substrate 5 is, for example, 100% or less. The total light transmittance of the light-transmitting substrate 5 is measured using a haze meter in accordance with JIS K7361-1:1997.

[0068] The haze of the light-transmitting substrate 5 is preferably 3.0% or less, more preferably 1.0% or less, and even more preferably 0.5% or less. The haze of the light-transmitting substrate 5 is, for example, 0% or more. The haze of the light-transmitting substrate 5 is measured using a haze meter in accordance with JIS K7136-1:2000.

[0069] The light-transmitting substrate 5 is not particularly limited as long as it is light-transmitting, and examples thereof include glass such as quartz glass and soda glass, and resin films such as polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polycarbonate (PC), polyimide (PI), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), cycloolefin copolymer (COC), norbornene-containing resin, polyethersulfone (PES), cellophane, and aromatic polyamide. When the display film 10 is used in a display, PET and TAC films are preferred.

[0070] The light-transmitting substrate 5 may be a polarizing plate. An example of a polarizing plate is one in which a polarizing element (for example, a PVA film) is sandwiched between a pair of protective layers (for example, a TAC film).

[0071] The thickness of the light-transmitting substrate 5 is preferably small from the viewpoint of weight reduction, but in consideration of productivity and handling, the thickness is preferably 1 μm to 5 mm, more preferably 10 to 500 μm, and even more preferably 25 to 150 μm.

[0072] The surface of the light-transmitting substrate 5 may be subjected to a surface treatment such as alkali treatment, plasma treatment, corona treatment, sputtering treatment, or saponification treatment, or a surface modification treatment such as application of a surfactant, a silane coupling agent, or the like, or Si vapor deposition, in order to improve adhesion to the antiglare layer 1 or the transparent adhesive layer 7.

[0073] (Transparent Adhesive Layer) The transparent adhesive layer 7 is not particularly limited, and a known transparent adhesive layer such as an OCA (optically transparent adhesive) can be used. The transparent adhesive layer 7 generally contains a base resin and further contains optional components as needed. Examples of the base resin for the transparent adhesive layer 7 include polyester-based resins, epoxy-based resins, polyurethane-based resins, silicone-based resins, and acrylic-based resins. Acrylic-based resins are preferred because of their high optical transparency and relatively low cost.

[0074] The total light transmittance of the transparent adhesive layer 7 is preferably 60% or more, more preferably 80% or more, and even more preferably 90% or more. The total light transmittance of the transparent adhesive layer 7 is, for example, 100% or less. The total light transmittance of the transparent adhesive layer 7 is measured using a haze meter in accordance with JIS K7361-1:1997.

[0075] [Method for Manufacturing Display Film] The method for manufacturing the display film 10 is not particularly limited, but examples thereof include a manufacturing method having the following steps (i) to (ii): (i) a step of manufacturing an anisotropic light-diffusing film 3. (ii) a step of bonding the anisotropic light-diffusing film 3 to a surface of an antiglare layer laminate 9, which has an antiglare layer 1 formed on one surface of a light-transmitting substrate 5, via a transparent adhesive layer 7.

[0076] (Step (i)) The anisotropic light-diffusing film 3 is produced, for example, with reference to the methods disclosed in WO 2021 / 187555, WO 2022 / 044598, and WO 2022 / 138390. A composition for an anisotropic light-diffusing film (a composition used to produce the anisotropic light-diffusing film 3, hereinafter referred to as a "photocurable resin composition" or "composition") is applied to a suitable substrate such as a transparent PET film to form a sheet, and an uncured resin composition layer is formed. This uncured resin composition layer is dried, if necessary, to volatilize the solvent, and then the uncured resin composition layer is irradiated with light to produce the anisotropic light-diffusing film 3.

[0077] The manufacturing method of the present invention mainly comprises the following steps: (1) Step 1-1: Providing an uncured resin composition layer on a substrate (2) Step 1-2: Obtaining parallel light from a light source (3) Optional Step 1-3: Obtaining directional light (4) Step 1-4: Curing the uncured resin composition layer

[0078] <<<Composition for Anisotropic Light-Diffusing Film>>> <<Components>> The composition for an anisotropic light-diffusing film according to the present invention contains component (A), which is a photopolymerizable compound. The composition for an anisotropic light-diffusing film also contains component (B), which is a photopolymerization initiator. Furthermore, the composition for an anisotropic light-diffusing film further contains component (C), which is a thermoplastic elastomer having a glass transition temperature of 0°C or lower.

[0079] The composition for an anisotropic light-diffusing film preferably contains a thermoplastic polymer (component (D)). Additionally, the composition for an anisotropic light-diffusing film preferably contains a polymerization inhibitor (component (E)). Furthermore, the composition for an anisotropic light-diffusing film may contain another component (F).

[0080] Each component will be described below.

[0081] In the following description, when an upper limit value and a lower limit value are separately described, all combinations of the upper limit value and the lower limit value are considered to be included in this specification.

[0082] In the present invention, the refractive index of each component is measured by a method in accordance with JIS K0062.

[0083] <Component (A): Photopolymerizable Compound> Examples of the photopolymerizable compound as component (A) include compounds (macromonomers, polymers, oligomers, monomers, etc.) having a radically polymerizable functional group with an unsaturated double bond, such as an acryloyl group, a methacryloyl group, or an allyl group.

[0084] Compounds having a radically polymerizable functional group (radical polymerizable compound) include compounds containing one or more unsaturated double bonds in the molecule. These compounds may be used alone or in combination. Methacrylates can also be used, but acrylates are generally preferred over methacrylates because they have a faster photopolymerization rate.

[0085] Among these, the (A) component is preferably composed of a (meth)acrylic acid ester, and in particular, preferably composed of a first (meth)acrylic acid ester having multiple aromatic rings and one (only one) (meth)acryloyl group, and a second (meth)acrylic acid ester that is a component different from the first (meth)acrylic acid ester and is a component (b1) and / or a component (b2). The second (meth)acrylic acid ester may be either the component (b1) or the component (b2), or may contain both the component (b1) and the component (b2). Furthermore, when the (A) component is composed of a (meth)acrylic acid ester, the (A) component may optionally contain a third (meth)acrylic acid ester or other (meth)acrylic acid ester each having one or more fluorene skeletons and one or more (meth)acryloyl groups.

[0086] ((First (meth)acrylic acid ester)) The first (meth)acrylic acid ester preferably has a biphenyl ring structure or a diphenyl ether structure as a structure containing a plurality of aromatic rings. The first (meth)acrylic acid ester may have only one such biphenyl structure or diphenyl ether structure in the skeleton, or two or more such biphenyl structures or diphenyl ether structures. By having such a structure, the (meth)acrylic acid ester has a very high refractive index.

[0087] The first (meth)acrylic acid ester is usually a high refractive index material. Specifically, the refractive index of the first (meth)acrylic acid ester is preferably 1.50 or more, more preferably 1.53 or more, and even more preferably 1.56 or more. The upper limit of the refractive index is not particularly limited, but is, for example, preferably 1.70 or less, more preferably 1.65 or less, and even more preferably 1.60 or less. By setting the refractive index of the first (meth)acrylic acid ester within this range, the diffusivity of the anisotropic light-diffusing film can be further improved.

[0088] Such a first (meth)acrylic acid ester is not particularly limited, but examples thereof include a biphenyl compound represented by the following general formula (1) and a diphenyl ether compound represented by the following general formula (2).

[0089]

[0090]

[0091] In general formula (1), R １ ~R １０ are independent of each other, and R １ ~R １０ Any one of the above is a substituent represented by the following general formula (3) or (4): The rest may be any as long as it does not contain a (meth)acryloyl group, and specific examples of the substituent include a hydrogen atom, a hydroxyl group, a carboxyl group, an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, a carboxyalkyl group, and a halogen atom.

[0092] In addition, in the general formula (2), R １１ ~R ２０ are independent of each other, and R １１ ~R ２０ Any one of the above is a substituent represented by the following general formula (3) or (4). The remaining group may be any group as long as it does not contain a (meth)acryloyl group, and specific examples of the substituent include a hydrogen atom, a hydroxyl group, a carboxyl group, an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, a carboxyalkyl group, and a halogen atom.

[0093]

[0094] (In general formula (3), R ２１ is a hydrogen atom or a methyl group, the number of carbon atoms n is an integer of 1 to 4, and the number of repetitions m is an integer of 1 to 10.

[0095]

[0096] (In general formula (4), R ２２ is a hydrogen atom or a methyl group, the number of carbon atoms n is an integer of 1 to 4, and the number of repetitions m is an integer of 1 to 10.

[0097] The repeat number m in the substituents represented by the general formulas (3) and (4) is usually preferably an integer of 1 to 10. The reason for this is that if the repeat number m exceeds 10, the refractive index improvement effect derived from the aromatic ring specific to the first (meth)acrylic acid ester is suppressed, and the diffusibility of the anisotropic light-diffusing film may be reduced. Therefore, the repeat number m in the substituents represented by the general formulas (3) and (4) is more preferably an integer of 1 to 4, and even more preferably an integer of 1 to 2. From the same viewpoint, the carbon number n in the substituents represented by the general formulas (3) and (4) is usually preferably an integer of 1 to 4, and even more preferably an integer of 1 to 2.

[0098] A specific example of the biphenyl compound represented by the general formula (1) is preferably a compound represented by the following formula (5).

[0099]

[0100] A specific example of the diphenyl ether compound represented by the above general formula (2) is preferably a compound represented by the following formula (6).

[0101]

[0102] The first (meth)acrylic acid ester may contain only one kind of the above-mentioned component, or may contain a plurality of kinds of the above-mentioned component.

[0103] (Viscosity of First (Meth)acrylic Acid Ester) The viscosity of the first (meth)acrylic acid ester at 25° C. is preferably 1000 mPa·s or less, more preferably 500 mPa·s or less, and even more preferably 100 mPa·s or less. The lower limit of the viscosity is not particularly limited, but is, for example, 1 mPa·s.

[0104] When the viscosity of the first (meth)acrylic acid ester at 25°C is within this range, the fluidity of the composition is increased when the components in component (A) are used in combination, thereby promoting phase separation of the components during curing and improving the diffusion performance of the resulting anisotropic light-diffusing film.

[0105] ((Second (meth)acrylic acid ester)) The second (meth)acrylic acid ester is a component different from the first (meth)acrylic acid ester, and is the component (b1) and / or the component (b2). The second (meth)acrylic acid ester may be either the component (b1) or the component (b2), or may contain both the component (b1) and the component (b2).

[0106] The component (b1) is a (meth)acrylic acid ester having a plurality of (meth)acryloyl groups.

[0107] The number of (meth)acryloyl groups in the (b1) component is not particularly limited, but may be 2 to 3 to improve the flexibility of the anisotropic light-diffusing film after photocuring, or may be 4 to 6 to improve the rigidity and heat resistance of the anisotropic light-diffusing film after photocuring.

[0108] The component (b1) is not particularly limited, but examples thereof include pentaerythritol tetraacrylate represented by the following general formula (7).

[0109]

[0110] When the second (meth)acrylic acid ester contains the component (b1), the first (meth)acrylic acid ester may be one that does not contain a hydroxyl group, a carboxyl group, or an amino group.

[0111] The component (b2) is a (meth)acrylic acid ester having one or more of a hydroxyl group, a carboxyl group, or an amino group, and one (only one) (meth)acryloyl group. The component (b2) may have two or more hydroxyl groups, carboxyl groups, or amino groups. In this case, the component (b2) may have two or more of the same type of functional group (e.g., two or more hydroxyl groups), or may have a total of two or more different types of functional groups (e.g., one or more hydroxyl groups and one or more carboxyl groups).

[0112] The component (b2) is not particularly limited, but examples thereof include (meth)acrylic acid esters represented by the following general formula (8).

[0113]

[0114] (In general formula (8), R ２５ is a hydrogen atom or a methyl group, and R ２６ is either a hydroxyl group, a carboxyl group, or an amino group, and R ２７ is a substituent selected from a hydrogen atom, a hydroxyl group, a carboxyl group, an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, a carboxyalkyl group, and a halogen atom.

[0115] The substituent R represented by the general formula (8) ２６ is usually either a hydroxyl group, a carboxyl group, or an amino group. The reason for this is that the functional group acts as a "hydrogen bond donor" and a "hydrogen bond acceptor" to generate hydrogen bonds in the molecular structure of the anisotropic light-diffusing film after photocuring, thereby forming a complex three-dimensional structure and weakening the π-π stacking interaction between the aromatic rings derived from the first (meth)acrylic acid ester. Therefore, in order to strengthen the effect of the hydrogen bonds, the functional group R ２６ is more preferably a hydroxyl group.

[0116] In addition, the substituent R ２７ is usually preferably a substituent selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxyl group, an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, a carboxyalkyl group, and a halogen atom, and among these, an alkoxy group having an aromatic ring is more preferred in order to increase the refractive index.

[0117] A specific example of the (meth)acrylic acid ester represented by the above general formula (8) is preferably a compound represented by the following formula (9).

[0118]

[0119] The second (meth)acrylic acid ester is preferably a high refractive index material. The refractive index is not particularly limited, but specifically, it is preferably 1.44 or more, more preferably 1.48 or more, and even more preferably 1.52 or more. The upper limit of the refractive index is not particularly limited, but it is preferably, for example, 1.57 or less. By setting the refractive index of the second (meth)acrylic acid ester in this range, the diffusivity of the anisotropic light-diffusing film can be further improved.

[0120] The second (meth)acrylic acid ester preferably has an aromatic ring structure in order to be a high refractive index material as described above.

[0121] The second (meth)acrylic acid ester may contain only one kind of the above-mentioned component, or may contain a plurality of kinds of the above-mentioned component.

[0122] In the production of an anisotropic light-diffusing film, increasing the difference in refractive index between a high refractive index material and a low refractive index material can accentuate the boundaries of the structures and enhance diffusivity. The first (meth)acrylic acid ester is considered useful as a high refractive index polymerizable compound, but it generates π-π stacking interactions. As mentioned above, it is believed that this π-π stacking interaction results in the appearance of a color tint.

[0123] Therefore, by using component (b1) as the second (meth)acrylic acid ester, the multiple (meth)acryloyl groups contained in component (b1) give the composition for anisotropic light-diffusing films a complex three-dimensional structure after photocuring, making it less likely that π-π stacking interactions will occur between aromatic rings.

[0124] Furthermore, by using component (b2) as the second (meth)acrylic acid ester, component (b2) has functional groups that act as a "hydrogen bond donor" and a "hydrogen bond acceptor." As a result, hydrogen bonds are introduced into the molecular structure of the anisotropic light-diffusing film after photocuring of the composition for an anisotropic light-diffusing film, resulting in a complex three-dimensional structure that makes it difficult for π-π stacking interactions between aromatic rings to occur. Hydroxyl groups, carboxyl groups, and amino groups are used as functional groups that achieve this effect.

[0125] (Third (meth)acrylic acid ester) The third (meth)acrylic acid ester is a (meth)acrylic acid ester having one or more fluorene skeletons and one or more (meth)acryloyl groups, and is an optional component.

[0126] The third (meth)acrylic acid ester may contain one or more aromatic rings (aromatic ring group / aromatic ring-containing group) as substituents on the fluorene skeleton, and preferably contains two or more aromatic rings as substituents on the fluorene skeleton. The upper limit of the number of aromatic rings as substituents on the fluorene skeleton contained in the third (meth)acrylic acid ester is not particularly limited, but is preferably, for example, 10 or less.

[0127] The number of (meth)acryloyl groups contained in the third (meth)acrylic acid ester is not particularly limited, but may be 1 or 2 or more, and preferably contains a plurality of (meth)acryloyl groups. The upper limit is not particularly limited, but is preferably 8 or less.

[0128] A specific example of the third (meth)acrylic acid ester containing two or more aromatic rings as substituents on the fluorene skeleton is a compound represented by the following formula (10).

[0129]

[0130] In the above formula (10), R Ａ and R Ｃare each independently a substituent containing a (meth)acryloyl group, and are preferably a (meth)acryloyloxy group (which may have 1 to 5 repeating groups each containing ethylene oxide (EO) or propylene oxide (PO)). Ｂ and R Ｄ are each independently a hydrogen atom or an aliphatic substituent having 1 to 6 carbon atoms.

[0131] More specifically, examples of the third (meth)acrylic acid ester include compounds represented by the following formulas (11) to (13).

[0132]

[0133]

[0134]

[0135] The third (meth)acrylic acid ester can be a commercially available product. Examples of commercially available products of the third (meth)acrylic acid ester include "A-BPEF-2" (9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., and "OGSOL EA-0200," "OGSOL EA-0300," "OGSOL EA-5060GP," and "OGSOL GA-2800" manufactured by Osaka Gas Chemicals Co., Ltd.

[0136] The refractive index of the third (meth)acrylic acid ester is preferably 1.50 or more, more preferably 1.53 or more, and even more preferably 1.56 or more. There is no particular upper limit to the refractive index, but for example, it is preferably 1.70 or less. By setting the refractive index of the third (meth)acrylic acid ester in this range, the diffusibility of the anisotropic light-diffusing film can be further improved.

[0137] The third (meth)acrylic acid ester may contain only one kind of the above-mentioned component, or may contain a plurality of kinds of the above-mentioned component.

[0138] ((Other (meth)acrylic acid esters)) The component (A) may contain other (meth)acrylic acid esters other than the first to third (meth)acrylic acid esters (other (meth)acrylic acid esters typically used in compositions for optical films), within the scope of not impairing the effects of the present invention.

[0139] (Viscosity of Component (A)) In the present invention, the viscosity of component (A) as a whole at 25°C is preferably 10,000 mPa·s or less, more preferably 5,000 mPa·s or less, even more preferably 3,000 mPa·s or less, and particularly preferably 1,000 mPa·s or less. The viscosity of component (A) as a whole at 25°C is most preferably 500 mPa·s or less, 250 mPa·s or less, or 100 mPa·s or less. The lower limit of the viscosity is not particularly limited, but is, for example, 1 mPa·s.

[0140] By ensuring that the viscosity of the entire (A) component at 25°C is within these ranges, the fluidity of the composition is increased when the individual components in the (A) component are used in combination, thereby promoting phase separation of the individual components during curing and improving the diffusion performance of the resulting anisotropic light-diffusing film.

[0141] <Component (B): Photopolymerization Initiator> The photopolymerization initiator of the component (B) is a compound that generates radical species when irradiated with active energy rays such as ultraviolet rays, and any conventionally known photopolymerization initiator can be used.

[0142] Examples of the photopolymerization initiator include benzophenone, benzil, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-diethoxyacetophenone, benzil dimethyl ketal, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl Examples of suitable fluorocarbon compounds include 1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(pyrrol-1-yl)phenyl]titanium, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. These compounds may be used alone or in combination.

[0143] The photopolymerization initiator may usually be used by directly dissolving the powder in the photopolymerizable compound, but if the solubility is poor, the photopolymerization initiator may be dissolved in a solvent in advance.

[0144] <Component (C): Thermoplastic elastomer having a glass transition temperature of 0°C or lower> In order to provide an anisotropic light-diffusing film that does not develop defects such as cracks or wrinkles even when used at temperatures from −15°C to 60°C, and a display film and display using the same, the photocurable resin composition contains a thermoplastic elastomer having a glass transition temperature of 0°C or lower.

[0145] The thermoplastic elastomer may be a photocurable thermoplastic elastomer or a thermosetting elastomer. When the thermoplastic elastomer is a thermosetting compound, it is preferable from the viewpoint of curing that the photocurable resin composition further contains a curing agent. In this case, the anisotropic light-diffusing layer is formed by photopolymerization and thermal polymerization, i.e., photopolymerization plus thermal polymerization.

[0146] Examples of thermoplastic elastomers include styrene-based elastomers, polyolefin-based elastomers, polyurethane-based elastomers (urethane polymers or copolymers), polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers (acrylic polymers or copolymers), soft polyvinyl chloride (containing a plasticizer), dynamically crosslinked elastomers, etc. Among these, styrene-based elastomers are preferred.

[0147] Examples of styrene-based elastomers include styrene-ethylene-propylene (SEP) copolymer, styrene-ethylene-propylene-styrene (SEPS) copolymer, styrene-ethylene-ethylene-propylene-styrene (SEEPS) copolymer, styrene-butadiene-styrene (SBS) copolymer, styrene-ethylene-butylene-styrene (SEBS) copolymer, styrene-isoprene-styrene (SIS) copolymer, etc. The styrene-based elastomer may be a crosslinkable hard block in which crosslinking points are introduced into a styrene-based hard block.

[0148] The dynamically crosslinked elastomer can be obtained by dynamically vulcanizing a compound of polypropylene and ethylene propylene rubber (EPDM), for example.

[0149] <Component (D): Thermoplastic Polymer> The composition for an anisotropic light-diffusing film preferably contains component (D), which is a thermoplastic polymer.

[0150] The glass transition temperature of component (D) is preferably −40° C. or higher, more preferably 0° C. or higher, and even more preferably 30° C. or higher. There are no particular limitations on the upper limit of the glass transition temperature, but it is preferably, for example, 150° C. or lower.

[0151] The glass transition temperature can be measured by a known method, for example, a method in accordance with JIS K7121-1987 "Method for measuring the glass transition temperature of plastics."

[0152] The weight average molecular weight of component (D) is preferably 1,000 to 500,000, more preferably 10,000 to 400,000, and even more preferably 50,000 to 300,000.

[0153] The weight average molecular weight can be measured by a known method, for example, by gel permeation chromatography (GPC) as a polystyrene-equivalent molecular weight.

[0154] By setting the glass transition temperature and weight average molecular weight of component (D) within the above ranges, it is possible to improve the compatibility with component (A) and produce an anisotropic light-diffusing film with excellent performance, improve durability in heat resistance tests and the like, and provide the anisotropic light-diffusing film before UV curing with an appropriate elastic modulus, thereby enabling storage in a roll, etc.

[0155] Component (D) is usually a low refractive index material. Specifically, the refractive index of component (D) is preferably less than 1.55, more preferably less than 1.50, and even more preferably less than 1.48. The lower limit of the refractive index is not particularly limited, but is preferably 1.35 or more, and more preferably 1.40 or more.

[0156] The difference (nA-nC) between the refractive index nA of the component (A) and the refractive index nC of the component (D) is preferably 0.01 to 0.3, more preferably 0.03 to 0.3, and particularly preferably 0.05 to 0.3.

[0157] The component (D) is not particularly limited, but examples thereof include acrylic resins, styrene resins, styrene-acrylic copolymers, polyurethane resins, polyester resins, epoxy resins, cellulose-based resins, silicone-based resins, vinyl acetate-based resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral resins, polyvinyl alcohol resins, polyvinyl formal resins, polyvinyl acetal resins, polyvinylidene fluoride, polymethyl methacrylate (PMMA)-polybutyl acrylate (PBA) block copolymers, polyvinylidene fluoride (PVDF)-hexafluoropropene (HFP) copolymers, and the like.

[0158] The component (D) is particularly preferably a urethane (meth)acrylate ester composed of a cyclic aliphatic compound having two isocyanate groups, a polyol compound, and a hydroxyalkyl (meth)acrylate ester.

[0159] Examples of cycloaliphatic compounds having two isocyanate groups include alicyclic polyisocyanates such as isophorone diisocyanate (IPDI) and hydrogenated diphenylmethane diisocyanate.

[0160] The polyol compound is preferably a diol compound, and more preferably a polyalkylene glycol, such as polyethylene glycol, polypropylene glycol, polybutylene glycol, or polyhexylene glycol, with polypropylene glycol being preferred.

[0161] Examples of hydroxyalkyl(meth)acrylate esters include 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 3-hydroxybutyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate.

[0162] The component (D) can be produced by synthesizing the above-mentioned components according to a conventional method.

[0163] The blending ratio of each component is not particularly limited, but for example, it is preferable that the molar ratio of "alicyclic compound having two isocyanate groups": "polyol compound": "hydroxyalkyl (meth)acrylic acid ester" be 1-5:1:1-5.

[0164] The component (D) may contain only one of the above-mentioned components, or may contain multiple components. When the component (D) is made up of multiple components, the refractive index of the component (B) may be the average value of the multiple components.

[0165] By incorporating such a (D) component, phase separation due to the difference in refractive index with the high refractive index material containing the (A) component can be facilitated, and when made into an anisotropic light-diffusing film, it is less likely to be indented and has excellent storage properties.

[0166] <Component (E): Polymerization Inhibitor> The component (E) is a polymerization inhibitor having a structure in which a carbonyl group or a hydroxyl group is added as a substituent of a conjugated cyclic compound.

[0167] Examples of the polymerization inhibitor having the above structure include so-called quinone-based and phenol-based polymerization inhibitors.

[0168] Specifically, the component (E) is preferably one or more compounds selected from the group consisting of compounds represented by the following chemical formulas (E1) to (E6).

[0169]

[0170] In formulas (E1) to (E6), R １ ~R ５ are each independently a hydrogen atom, a halogen atom, a carboxyl group, or a C1 to C4 (preferably C1 to C3) alkoxy group (e.g., a methoxy group, an ethoxy group, or a propyloxy group) or alkyl group (e.g., a methyl group, an ethyl group, a propyl group, or a tert-butyl group).

[0171] Thus, the component (E) is preferably a hydroquinone-based (e.g., the above formula (E1)), quinone methide-based (e.g., the above formulas (E2) and (E4)), benzoquinone-based (e.g., the above formula (E3)), phenol-based (e.g., the above formula (E5)), or catechol-based (e.g., the above formula (E6)) polymerization inhibitor. Furthermore, the component (E) is more preferably a hydroquinone-based, quinone methide-based, or benzoquinone-based polymerization inhibitor, and particularly preferably a benzoquinone-based polymerization inhibitor.

[0172] The polymerization inhibitor may have a structure to which a carbonyl group or a hydroxyl group is added. Therefore, in addition to the compounds represented by any of the above formulae (E1) to (E6), pyrogallol-based and naphthoquinone-based polymerization inhibitors may also be used.

[0173] In a composition for an anisotropic light-diffusing film containing a high refractive index material (A) component and a polymerization initiator, further containing a specified polymerization inhibitor makes the growth of the structural region described below appropriate, thereby achieving the effect of improving the optical properties (particularly the diffusion width).

[0174] <Component (F): Other Components> As the component (F), which is another component, the composition may contain various known dyes, sensitizers, other known additives, etc., for the purpose of improving photopolymerization, etc. The composition may also contain a solvent, a dispersion medium, etc. These are optional components and may be used alone or in combination, or may be omitted.

[0175] Furthermore, a curing agent capable of curing the photopolymerizable compound by heating can be used in combination with the photopolymerization initiator.

[0176] Examples of solvents that can be used when preparing a composition containing a photopolymerizable compound include ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, and xylene.

[0177] If the acid generator remains after the composition is cured, it may cause problems with other components when used in a device such as a display. Therefore, it is preferable that the composition does not contain an acid generator as another component. For example, it is preferable that the content of the acid generator in the composition is 1% or less.

[0178] <<Content>> <Component (A)> The content of component (A) relative to the total solid content of the composition (total amount of non-volatile components excluding volatile solvents) is not particularly limited, but is preferably 30 wt % or more, 35 wt % or more, 40 wt % or more, or 45 wt % or more. The upper limit is not particularly limited, but is, for example, 99 wt %, 95 wt %, 90 wt %, 85 wt %, 80 wt %, 70 wt %, or 60 wt %.

[0179] The content of the second (meth)acrylic acid ester is 50 parts by weight to 1,000 parts by weight, more preferably 65 parts by weight to 900 parts by weight, and even more preferably 75 parts by weight to 200 parts by weight, relative to 100 parts by weight of the content of the first (meth)acrylic acid ester.

[0180] The content of the third (meth)acrylic acid ester in the composition is 3 parts by weight to 100 parts by weight, preferably 4 parts by weight to 50 parts by weight, and more preferably 5 parts by weight to 25 parts by weight, based on 100 parts by weight of the content of the other (A) component.

[0181] The total content of the first to third (meth)acrylic acid esters relative to the component (A) can be 50% by weight or more (preferably 70% by weight or more, 80% by weight or more, or 90% by weight or more).

[0182] <Component (B)> The content of component (B) is preferably 0.1 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, and even more preferably 0.1 to 7 parts by weight, relative to 100 parts by weight of component (A).

[0183] <Component (C)> The blending ratio of the thermoplastic elastomer in the composition for an anisotropic light-diffusing film is preferably 30% by weight or less based on the entire composition for an anisotropic light-diffusing film.

[0184] <Component (D)> The content of component (D) is preferably 10 to 400 parts by weight, more preferably 25 to 150 parts by weight, and even more preferably 40 to 100 parts by weight, relative to 100 parts by weight of the content of component (A). From another perspective, the content of component (D) relative to the total amount of non-volatile components of the composition (amount excluding solvents and dispersion media) is preferably 10 to 80% by weight, preferably 15 to 70% by weight, and more preferably 20 to 60% by weight.

[0185] <Component (E)> The content of component (E) in the composition is preferably 0.001 to 1 part by weight, more preferably 0.005 to 0.5 parts by weight, more preferably 0.008 to 0.1 parts by weight, and even more preferably 0.015 to 0.05 parts by weight, based on 100 parts by weight of the total amount of non-volatile components of the composition. From another perspective, the content of component (E) in the composition relative to the total amount of non-volatile components of the composition is preferably 0.001 to 0.5% by weight, more preferably 0.005 to 0.1% by weight, and even more preferably 0.01 to 0.04% by weight.

[0186] <Component Composition> The total content of the components (A) and (D) relative to the total solid content of the composition (total amount of non-volatile components excluding volatile solvents) is not particularly limited, and can be, for example, 50 wt % or more, 60 wt % or more, 70 wt % or more, 80 wt % or more, 90 wt % or more, 95 wt % or more, 99 wt % or more, 100 wt %, etc.

[0187] By setting the total content of the components (A) and (D) in the composition within the above range, the interaction between the components can be made appropriate.

[0188] In addition, in the composition, the ratio of [content of component (E) / content of component (B)] is preferably 0.005 to 0.1, and more preferably 0.01 to 0.05.

[0189] <Step 1-1: Step of Providing an Uncured Resin Composition Layer on a Substrate> Conventional coating methods and printing methods are used to provide the photocurable resin composition as a sheet-like uncured resin composition layer on a substrate. Specifically, coating methods such as air doctor coating, bar coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, calendar coating, dam coating, dip coating, and die coating, as well as printing methods such as intaglio printing such as gravure printing and stencil printing such as screen printing, can be used. When the composition has a low viscosity, a dam of a certain height can be provided around the substrate, and the composition can be cast into the area surrounded by the dam.

[0190] In step 1-1, in order to prevent oxygen inhibition of the uncured resin composition layer and efficiently form the columnar regions that are characteristic of the anisotropic light-diffusing film, it is also possible to laminate a mask that adheres closely to the light-irradiated side of the uncured resin composition layer and locally changes the light irradiation intensity.

[0191] The mask material is preferably a matrix in which a light-absorbing filler such as carbon is dispersed, so that a portion of the incident light is absorbed by the carbon but the openings allow sufficient light to pass through. Examples of such matrices include transparent plastics such as polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyvinyl acetate (PVAc), polyvinyl alcohol (PVA), acrylic resin, and polyethylene, as well as inorganic materials such as glass and quartz. The mask may be a sheet containing such a matrix and patterned to control the amount of UV light transmitted, or a matrix containing a pigment that absorbs UV light.

[0192] When such a mask is not used, it is also possible to prevent oxygen inhibition of the uncured resin composition layer by performing light irradiation under a nitrogen atmosphere. Furthermore, simply laminating a normal transparent film on the uncured resin composition layer is also effective in preventing oxygen inhibition and promoting the formation of columnar regions. Light irradiation through such a mask or transparent film causes a photopolymerization reaction in the composition containing the photopolymerizable compound according to the irradiation intensity, which easily generates a refractive index distribution, and is effective for producing the anisotropic light-diffusing film according to the present embodiment.

[0193] <Step 1-2: Step of Obtaining Parallel Light Beams from a Light Source> As the light source, a short-arc ultraviolet light source is usually used, and specifically, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a xenon lamp, etc. can be used. At this time, it is necessary to obtain light beams parallel to the desired scattering central axis, and such parallel light beams can be obtained, for example, by arranging a point light source and arranging an optical lens such as a Fresnel lens between this point light source and the uncured resin composition layer to irradiate parallel light beams, or by arranging a reflecting mirror behind the light source so that light is emitted as a point light source in a predetermined direction.

[0194] <Optional Step 1-3: Step of Obtaining Directional Light Beams> Optional Step 1-3 is a step of making parallel light beams incident on a directional diffusion element to obtain directional light beams. Figures 5 and 6 are schematic diagrams showing a method for producing an anisotropic light-diffusing film according to the present invention, which includes optional Step 1-3.

[0195] The directional diffusion elements 301 and 302 used in optional step 1-3 may be any elements that impart directionality to the parallel light beam D incident from the light source 300.

[0196] 5 and 6 show that directional light E is incident on the uncured resin composition layer 303 in a state in which it is diffused largely in the X direction and hardly diffused in the Y direction. To obtain such directional light, for example, a method can be adopted in which needle-shaped fillers with a high aspect ratio are contained in the directional diffusion elements 301 and 302 and the needle-shaped fillers are oriented so that their major axis direction extends in the Y direction. The directional diffusion elements 301 and 302 can be formed using various methods other than the method using needle-shaped fillers.

[0197] Here, the aspect ratio of the directional light E is preferably set to 2 to 50. A columnar region having an aspect ratio that roughly corresponds to this aspect ratio is formed.

[0198] In optional step 1-3, the size (aspect ratio, minor axis SA, major axis LA, etc.) of the columnar regions to be formed can be appropriately determined by adjusting the spread of the directional light E. For example, the anisotropic light-diffusing film of this embodiment can be obtained in both Figures 5 and 6. The difference between Figures 5 and 6 is that the spread of the directional light E is large in Figure 5 but small in Figure 6. The size of the columnar regions will differ depending on the size of the spread of the directional light E.

[0199] The spread of the directional light E depends mainly on the type of directional diffusion elements 301 and 302 and the distance from the uncured resin composition layer 303. As the distance decreases, the size of the columnar region decreases, and as the distance increases, the size of the columnar region increases. Therefore, the size of the columnar region can be adjusted by adjusting the distance.

[0200] <Step 1-4: Step of curing the uncured resin composition layer> The light irradiated onto the uncured resin composition layer to cure the uncured resin composition layer must contain a wavelength capable of curing the photopolymerizable compound, and light from a mercury lamp with a wavelength centered at 365 nm is usually used. When this wavelength band is used to produce an anisotropic light-diffusing film, the illuminance is 0.01 mW / cm ２ ~100mW / cm ２The range of 0.1 mW / cm is preferred. ２ ~20mW / cm ２ It is more preferable that the illuminance is 0.01 mW / cm ２ If the curing power is less than 100 mW / cm, a long time is required for curing, resulting in poor production efficiency. ２ If the curing time exceeds this limit, the photopolymerizable compound will cure too quickly, resulting in no structure formation and making it impossible to achieve the desired optical properties.

[0201] The light irradiation time is not particularly limited, but is preferably 10 to 180 seconds, and more preferably 30 to 120 seconds. By irradiating the light beam in the above manner, the anisotropic light-diffusing film of the present embodiment can be obtained.

[0202] As described above, the anisotropic light-diffusing film is obtained by forming a specific internal structure in the uncured resin composition layer through irradiation with low-intensity light for a relatively long period of time. Therefore, such light irradiation alone may leave unreacted monomer components, causing stickiness and problems with handling and durability. In such cases, it is recommended to use a low-intensity light source of 1000 mW / cm. ２ The remaining monomer can be polymerized by additionally irradiating the film with light of such high intensity. The light irradiation may be performed from the side opposite to the side where the mask is laminated.

[0203] As described above, when curing the uncured resin composition layer, the scattering central axis of the resulting anisotropic light-diffusing film can be made as desired by adjusting the angle of light irradiated onto the uncured resin composition layer.

[0204] The anisotropic light-diffusing film may further have other layers (adhesive layer, functional layer, transparent film layer, etc.).

[0205] (Step (ii)) In step (ii), the surface of the antiglare layer laminate 9, in which the antiglare layer 1 is formed on one surface of the translucent substrate 5, facing the translucent substrate 5 is bonded to the anisotropic light-diffusing film 3 obtained in step (i) via the transparent adhesive layer 7. This gives a film 10 for displays.

[0206] The antiglare layer laminate 9 may be a commercially available product, or may be produced by a known production method. The antiglare layer laminate 9 can be produced by forming an antiglare layer 1 on one surface of a light-transmitting substrate 5. The method for forming the antiglare layer 1 is not particularly limited and may be a known method. For example, methods described in WO 2005 / 093468, WO 2008 / 093769, JP 2010-248451 A, JP 2011-013238 A, JP 2010-256882 A, etc. may be mentioned.

[0207] A commercially available transparent adhesive sheet can be used as the transparent adhesive layer 7. A transparent adhesive sheet manufactured by a known manufacturing method may also be used.

[0208] Although the display film of the present invention has been described above by showing an embodiment, the present invention is not limited to the above embodiment. Each configuration and combination thereof in the above embodiment is an example, and addition, omission, substitution, and other modifications of the configuration are possible within the scope of the present invention.

[0209] For example, a display film 11 shown in Fig. 3 may have a configuration that does not include the light-transmitting substrate 5 and the transparent adhesive layer 7. Such a display film can be obtained, for example, by directly forming an antiglare layer on one surface of the anisotropic light-diffusing film 3.

[0210] 4, a display film 12 may be configured without the transparent adhesive layer 7. Such a display film can be obtained, for example, by directly forming an anisotropic light-diffusing film 3 on the surface of a light-transmitting substrate 5 opposite to the antiglare layer 1 side.

[0211] The display film of the present invention may further include layers other than the antiglare layer 1, the anisotropic light-diffusing film 3, the light-transmitting substrate 5, and the transparent adhesive layer 7. Examples of such layers include a retardation layer, a light-reflecting layer, and an optical control layer. The other layers may be provided between the antiglare layer 1 and the anisotropic light-diffusing film 3, or may be provided on the side of the anisotropic light-diffusing film 3 opposite to the side on which the antiglare layer 1 is provided.

[0212] [Display] The display of the present invention comprises the display film of the present invention.

[0213] Examples of displays include liquid crystal displays (LCDs), plasma display panels (PDPs), organic electroluminescence (EL) displays, field emission displays (FEDs), rear projectors, cathode ray tube displays (CRTs), surface-emitting displays (SEDs), and electronic paper.

[0214] The display of the present invention typically comprises a display body having a display surface and a display film of the present invention disposed on the display surface of the display body. In this case, the display film of the present invention is disposed with the antiglare layer side facing the viewing side (opposite the display surface side). It is preferable to dispose the antiglare layer so that it is on the most visible side in the thickness direction of the display film. The display film can be attached to the display surface via a transparent adhesive layer or the like.

[0215] Next, the present invention will be explained in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[0216] (Production of Anisotropic Light-Diffusing Film) Anisotropic light-diffusing films of examples of the present invention and comparative examples were produced according to the following method.

[0217] [Example 1] 1. Preparation of composition solution 1 for an anisotropic light-diffusing film The various materials shown below were mixed and stirred in the amounts shown below to obtain composition solution 1 for an anisotropic light-diffusing film.

[0218] Component (A): 100 parts by weight of ethylene oxide (EO)-modified bisphenol A diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Acrylate (registered trademark) BP-4EAL, refractive index: 1.54 (25°C)); Component (B): 60 parts by weight of polyvinyl acetate (PVAc) (refractive index: 1.460, weight-average molecular weight: 200,000, glass transition temperature: 40°C); Component (C): 20 parts by weight of styrene-isoprene-styrene (SIS) copolymer (manufactured by Kuraray Co., Ltd., trade name: Hybler (registered trademark) 5125, glass transition temperature: -13°C); Component (D): 2 parts by weight of 2,2-dimethoxy-2-phenylacetophenone; Solvent: 150 parts by weight of butyl acetate.

[0219] 2. Preparation of Composition Layer 1 for Anisotropic Light-Diffusing Film The obtained composition solution 1 for anisotropic light-diffusing film was applied to a 100 μm-thick PET film (manufactured by Toyobo Co., Ltd., product name: A4360) using an applicator. The coating was then dried in a clean oven with the temperature inside the drying furnace set to 80° C., thereby obtaining a composition layer 1 for anisotropic light-diffusing film with a thickness of 40 μm.

[0220] 3. Preparation of Anisotropic Light-Diffusing Film 1 Next, a polyvinyl alcohol film with uniformly dispersed carbon (hereinafter referred to as a PVA mask) was laminated using a laminator on the surface of the composition layer for anisotropic light-diffusing films 1 that was not in contact with the PET film. The resulting laminate was heated to 60°C, and while the temperature was kept constant, parallel light emitted from an ultraviolet epi-irradiation unit (manufactured by Hamamatsu Photonics, product name: L2859-01) was irradiated from above the PVA mask surface at an irradiation intensity of 2.0 mW / cm. ２ The anisotropic light-diffusing film 1 was irradiated at a wavelength of 1000 nm for 30 seconds. At this time, the angle of the light irradiation was not tilted from the normal direction of the composition layer 1 for an anisotropic light-diffusing film. The PVA mask and PET film were peeled off from the obtained laminate, to obtain an anisotropic light-diffusing film 1 of Example 1 which was a single-layer anisotropic light-diffusing layer 1. The thickness of the anisotropic light-diffusing film 1 was 40 μm, and the average height of the columnar structures was 40 μm.

[0221] Example 2 The same method as in Example 1 was carried out, except that the component (A) was changed to 10 parts by weight of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name: A-BPEF-2, refractive index: 1.62 (25°C), number of aromatic rings contained as substituents on the fluorene skeleton: 2) and 90 parts by weight of m-phenoxybenzyl acrylate (refractive index: 1.57 (25°C), viscosity: 18 mPa s (25°C)). An anisotropic light-diffusing film 2 of Example 2, which was a single-layer anisotropic light-diffusing layer 2, was obtained. The thickness of the anisotropic light-diffusing film 2 was 40 μm, and the average height of the columnar structures was 40 μm.

[0222] Example 3 The same method as in Example 2 was carried out, except that in the formulation of Example 2, component (C) was changed to 20 parts by weight of a styrene-ethylene-ethylene-propylene-styrene (SEEPS) copolymer (manufactured by Kuraray Co., Ltd., product name: Hybler (registered trademark) 7311F, glass transition temperature: -32°C), to obtain an anisotropic light-diffusing film 3 of Example 3, which was a single-layer anisotropic light-diffusing layer 3. The thickness of the anisotropic light-diffusing film 3 was 40 μm, and the average height of the columnar structures was 40 μm.

[0223] Example 4 The same method as in Example 2 was carried out, except that in the formulation of Example 2, component (C) was changed to 20 parts by weight of a thermoplastic polyether ester elastomer (manufactured by Toray Celanese Inc., product name: Hytrel (registered trademark) 5557, glass transition temperature: -50°C), to obtain an anisotropic light-diffusing film 4 of Example 4, which was a single-layer anisotropic light-diffusing layer 4. The thickness of the anisotropic light-diffusing film 4 was 40 μm, and the average height of the columnar structures was 40 μm.

[0224] Example 5 A laminate comprising a composition layer for an anisotropic light-diffusing film and a PVA mask was subjected to the same procedure as in Example 2, except that parallel light emitted from an incident-light irradiation unit was converted into a linear light beam via a directional diffusion element that gave the light beam an aspect ratio of 40, and the linear light beam was irradiated in a direction (hereinafter referred to as the MD direction) perpendicular to both the direction in which the light was diffused by the directional diffusion element and the thickness direction of the composition layer for an anisotropic light-diffusing film, without being tilted from the normal direction to the composition layer for an anisotropic light-diffusing film, to obtain an anisotropic light-diffusing film 5 of Example 5, which was a single-layer anisotropic light-diffusing layer 5. The thickness of the anisotropic light-diffusing film 5 was 40 μm, and the average height of the columnar structures was 40 μm.

[0225] Example 6 A laminate comprising a composition layer for an anisotropic light-diffusing film and a PVA mask was subjected to the same procedure as in Example 2, except that parallel light emitted from an incident-light irradiation unit was converted into a linear light beam via a directional diffusion element such that the aspect ratio of the light beam was 3, and the linear light beam was irradiated in the MD direction at an angle not tilted from the normal direction of the composition layer for an anisotropic light-diffusing film, thereby obtaining an anisotropic light-diffusing film 6 of Example 6, which was a single-layer anisotropic light-diffusing layer 6. The thickness of the anisotropic light-diffusing film 6 was 40 μm, and the average height of the columnar structures was 40 μm.

[0226] [Example 7] The same procedure as in Example 6 was carried out, except that the thickness of the anisotropic light-diffusing film 7 was 30 μm and the average height of the columnar structures was 30 μm, to obtain an anisotropic light-diffusing film 6 of Example 7, which was a single-layer anisotropic light-diffusing layer 7.

[0227] Comparative Example 1 The same procedure as in Example 1 was carried out except that the material for component (C) was not used, to obtain an anisotropic light-diffusing film a of Comparative Example 1, which was a single-layer anisotropic light-diffusing layer a. The thickness of the anisotropic light-diffusing film a was 40 μm, and the average height of the columnar structures was 40 μm.

[0228] [Comparative Example 2] The same procedure as in Example 2 was carried out except that the material for component (C) was not used, to obtain an anisotropic light-diffusing film b of Comparative Example 2, which was a single-layer anisotropic light-diffusing layer b. The thickness of the anisotropic light-diffusing film b was 40 μm, and the average height of the columnar structures was 40 μm.

[0229] Comparative Example 3 The same procedure as in Example 1 was carried out, except that component (C) was changed to 20 parts by weight of a styrene-isoprene-styrene (SIS) copolymer (manufactured by Kuraray Co., Ltd., product name: Hybler (registered trademark) 5127, glass transition temperature: 8°C), to obtain an anisotropic light-diffusing film c of Comparative Example 3, which was a single-layer anisotropic light-diffusing layer c. The thickness of the anisotropic light-diffusing film c was 40 μm, and the average height of the columnar structures was 40 μm.

[0230] (Evaluation Method) The anisotropic light-diffusing films of the examples and comparative examples of the present invention prepared as described above were evaluated as follows.

[0231] [Thickness of Anisotropic Light-Diffusing Film] A cross section of the film was formed using a microtome and observed under an optical microscope. On this cross section, the length between the surface of the film and the opposite surface in the direction perpendicular to the film plane (thickness direction) was measured at 10 points. The average value of the measured values ​​obtained at this time was taken as the thickness of the anisotropic light-diffusing layer film.

[0232] [Average Height of Columnar Structures of Anisotropic Light Diffusion Layer] The anisotropic light diffusion layer (anisotropic light diffusion film) was placed horizontally with one surface facing downward and the other surface facing upward, and the heights from the bottom to the top of 20 columnar structures were measured using an optical microscope, and the average value was taken as the average height of the columnar structures of the anisotropic light diffusion layer.

[0233] [Linear Transmittance] The linear transmittance, which indicates the light diffusion properties of the anisotropic light-diffusing films of the Examples and Comparative Examples, was evaluated using a variable-angle goniophotometer (manufactured by Genesia) capable of arbitrarily varying the projection angle of the light source and the reception angle of the detector, as shown in Fig. 7. As shown in Fig. 7, a sample 110 of each anisotropic light-diffusing film of the Examples and Comparative Examples was placed between a light source 201 and a detector 202. Here, the light source 201 and the detector 202 were both fixed. In this evaluation, the incident angle of light I from the light source 201 was defined as 0° when it was incident from the normal direction of the anisotropic light-diffusing film, and the anisotropic light-diffusing film was positioned so that it could be arbitrarily rotated about a central axis L in a direction perpendicular to both the MD direction and the thickness direction of the anisotropic light-diffusing film (hereinafter referred to as the TD direction). Next, the anisotropic light-diffusing films of the Examples and Comparative Examples were rotated continuously in 1° increments within the range of -75° to 75°, and the amount of light transmitted in the linear direction (linear transmitted light amount) at each incident light angle was measured. The linear transmitted light amount was measured by measuring wavelengths in the visible light range using a visibility filter. The linear transmitted light amount was then calculated as the ratio of the linear transmitted light amount (amount of incident light, incident light amount) irradiated directly from the light source 201 to the detector 202 without passing through the anisotropic light-diffusing film, to the linear transmitted light amount. In the present invention, the linear transmittance was measured at angles of 0°, 15°, and 45°.

[0234] [Aspect Ratio] The surface (the UV-irradiated side when produced) of each anisotropic light-diffusing layer (anisotropic light-diffusing film) in Examples and Comparative Examples was observed with an optical microscope, the diameters (diameter or major and minor diameters) of 20 randomly selected columnar structures were measured, and the average values ​​were calculated. The aspect ratio was calculated based on the average major diameter / average minor diameter when the cross-sectional shape was elliptical and had major and minor diameters, and the aspect ratio was calculated as 1 when the cross-sectional shape was circular and had only a diameter.

[0235] [Dynamic Viscoelasticity] Measurements were carried out in accordance with JIS K 7244-1 using a Dynamic Mechanical Spectrometer (trade name: DMS6100) manufactured by Hitachi High-Tech Science Corporation, under the following conditions: tensile mode, frequency: 1 Hz, load: 10 mN, measurement temperature range: -50 to 100°C, and heating rate: 3°C / min. From the obtained storage modulus (E'), loss modulus (E"), and loss tangent (tan δ), values ​​at -15°C, 25°C, and 60°C were calculated. The minimum peak temperature on the low-temperature side of tan δ was also calculated.

[0236] The evaluation criteria for dynamic viscoelasticity (storage modulus, loss modulus, and loss tangent) were as follows:

[0237] (Storage modulus) When all of the following conditions were satisfied, the result was rated as "○" (good), and when any one of the conditions was not satisfied, the result was rated as "×" (bad). ７ Pa ~ 2.0 x 10 ９ Pa 25℃: 1.0×10 ７ Pa ~ 2.0 x 10 ９ Pa 60℃: 1.0×10 ６ Pa ~ 2.0 x 10 ８ Pa

[0238] (Loss modulus) When all of the following conditions were met, it was rated as "○" (good), and when even one of the conditions was not met, it was rated as "×" (bad). ７ Pa ~ 2.0 x 10 ９ Pa 25℃: 1.0×10 ７ Pa ~ 2.0 x 10 ９ Pa 60℃: 1.0×10 ６ Pa ~ 2.0 x 10 ８ Pa

[0239] (Loss tangent) When the following conditions were met, it was rated as "○" (good), and when they were not met, it was rated as "×" (bad). -15 to 60°C: 0.07 to 0.8

[0240] [Bending properties] Each anisotropic light-diffusing film of the Examples and Comparative Examples was held for 10 minutes or more under each of the temperature environments of -15°C, 25°C, and 60°C. Subsequently, under each of the temperature environments, each anisotropic light-diffusing film of the Examples and Comparative Examples held under each of the temperature environments was bent 180° while one end of the film was aligned with a φ2 mm stainless steel cylindrical rod, and then returned to its original flat shape. The condition of each anisotropic light-diffusing film of the Examples and Comparative Examples at this time (presence or absence of cracks or wrinkles) was visually confirmed.

[0241] [Scintillation] 1. Preparation of Antiglare Layer Laminate A laminate containing 100 parts by weight of urethane acrylate (manufactured by DIC Corporation, trade name: Unidic (registered trademark) 17-806) as a binder resin, 1.56 parts by weight of porous silica particles (manufactured by Fuji Silysia Chemical Ltd., trade name: Silohobic (registered trademark) 702, weight average particle size: 2.5 μm, refractive index: 1.46), 1.35 parts by weight of porous silica particles (manufactured by Fuji Silysia Chemical Ltd., trade name: Silohobic (registered trademark) 100, weight average particle size: 1.4 μm, refractive index: 1.46), and a photopolymerization initiator (IGM Resins Three parts by weight of a leveling agent (manufactured by DIC Corporation, trade name: PC4100, solids content 10%) was mixed with 0.2 parts by weight of a composition for an antiglare layer having a solids content of 32% by weight. The mixture was diluted with a toluene / cyclopentanone (CPN) mixed solvent (weight ratio 70 / 30) to prepare a composition for an antiglare layer having a solids content of 32% by weight. The composition for an antiglare layer was applied to a triacetyl cellulose film (manufactured by Konica Minolta Opto, trade name: KC8UX2M, thickness: 80 μm) as a light-transmitting substrate using a Comma Coater. The composition was heated at 80° C. for 1 minute, and then irradiated with a high-pressure mercury lamp with an integrated light dose of 300 mJ / cm. ２The antiglare layer of the prepared antiglare layer laminate was irradiated with ultraviolet light of 1000 W at ...

[0242] 2. Preparation of a transparent adhesive layer with a PET film 100 parts by weight of an acrylic adhesive (manufactured by Soken Chemical & Engineering Co., Ltd., trade name: SK Dyne (registered trademark) 1811L) and 0.45 parts by weight of a curing agent (manufactured by Soken Chemical & Engineering Co., Ltd., trade name: L-45) were mixed in a solvent of 15 parts by weight of toluene and 4 parts by weight of ethyl acetate to obtain a coating liquid. This coating liquid was applied to a 100 μm thick PET film (manufactured by Toyobo Co., Ltd., trade name: A4360) using an applicator to obtain a coating film, and then this coating film was dried in a clean oven with the drying oven temperature set to 80 ° C. to obtain a transparent adhesive layer with a PET film and a film thickness of 15 μm. The total light transmittance of the prepared transparent adhesive layer with PET film was measured using a haze meter (product name: NDH-2000) manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K7361-1:1997, and was found to be 91%.

[0243] 3. Preparation of Display Films One side of each anisotropic light-diffusing film prepared in the Examples and Comparative Examples was bonded to the translucent substrate side of the prepared anti-glare layer laminate via the prepared transparent adhesive layer with a PET film, thereby obtaining display films 1 to 7 of Examples 8 to 14 and display films a to c of Reference Examples 1 to 3. The prepared anti-glare layer laminate was directly used as anti-glare layer laminate 1 of Comparative Example 4. The relationship between these components and the structures that were the prepared display films or anti-glare laminates is shown in Table 5.

[0244] 4. Evaluation of Scintillation The surface of the anisotropic light-diffusing film side of films for displays 1 to 7 of Examples 8 to 14 and films for displays a to c of Reference Examples 1 to 3, or the surface of the light-transmitting substrate side of antiglare layer laminate 1 of Comparative Example 4, was attached to a commercially available organic EL panel using the adhesive layer of the prepared transparent adhesive layer with a PET film, and the presence or absence of scintillation in the output image was then visually confirmed.

[0245] The results of linear transmittance and aspect ratio are shown in Table 1, the results of dynamic viscoelasticity in Tables 2 and 3, the results of bending properties in Table 4, and the results of scintillation in Table 5.

[0246]

[0247]

[0248]

[0249]

[0250]

[0251] According to the present invention, it is possible to provide an anisotropic light-diffusing film that does not develop abnormalities such as cracks or wrinkles even when used at temperatures from -15°C to 60°C in a display that requires bending or in a curved window, a display film using the same, and a display using the same.

[0252] DESCRIPTION OF SYMBOLS 1...antiglare layer, 1a...first surface, 1b...second surface, 3...anisotropic light-diffusing film, 5...light-transmitting substrate, 7...transparent adhesive layer, 9...antiglare layer laminate, 10, 11, 12...display film, 30...anisotropic light-diffusing layer, 31...matrix region, 32...columnar region, 33...columnar structure, 110...sample, 201...light source, 202...detector, 300...light source, 301, 302...directional diffusion element, 303...uncured resin composition layer.

Claims

1. An anisotropic light-diffusing film having an anisotropic light-diffusing layer formed by photopolymerization of a composition containing a photopolymerizable compound, a photopolymerization initiator, and a thermoplastic elastomer having a glass transition temperature of 0°C or lower, characterized in that the anisotropic light-diffusing layer has a matrix region and a columnar region consisting of a plurality of columnar structures having a refractive index different from that of the matrix region.

2. The storage modulus of the anisotropic light-diffusing layer at −15° C. is 1.0×10 ７ Pa ~ 2.0 x 10 ９ Pa and loss modulus of 1.0 × 10 ７ Pa ~ 2.0 x 10 ９ Pa, and the storage modulus of the anisotropic light-diffusing layer at 25°C is 1.0 × 10 ７ Pa ~ 2.0 x 10 ９ Pa and loss modulus of 1.0 × 10 ７ Pa ~ 2.0 x 10 ９ Pa, and the storage modulus of the anisotropic light-diffusing layer at 60°C is 1.0×10 ６ Pa ~ 2.0 x 10 ８ Pa and loss modulus of 1.0 × 10 ６ Pa ~ 2.0 x 10 ８ The anisotropic light-diffusing film according to claim 1 , wherein the thickness of the anisotropic light-diffusing film is 100 μm or less.

3. The anisotropic light-diffusing film according to claim 1, wherein the loss tangent of the anisotropic light-diffusing layer at temperatures from -15°C to 60°C is 0.07 to 0.

8.

4. The anisotropic light-diffusing film according to any one of claims 1 to 3, wherein the peak temperature on the lowest temperature side of the loss tangent of the anisotropic light-diffusing layer is 0°C or lower.

5. The anisotropic light-diffusing film according to any one of claims 1 to 3, characterized in that the blending ratio of the thermoplastic elastomer is 30% or less of the entire composition.

6. The anisotropic light-diffusing film according to any one of claims 1 to 3, characterized in that the linear transmittance at an incident light angle of 0° is 1% or more and less than 20%, the linear transmittance at an incident light angle of 15° is 1% or more and less than 20%, and the linear transmittance at an incident light angle of 45° is 30% or more and less than 80%.

7. The anisotropic light-diffusing film according to any one of claims 1 to 3, wherein the aspect ratio of the cross section perpendicular to the column axis direction of the columnar structures is less than 2.

8. The anisotropic light-diffusing film according to any one of claims 1 to 3, wherein the aspect ratio of the cross section perpendicular to the column axis direction of the columnar structures is 2 to 40.

9. The anisotropic light-diffusing film according to any one of claims 1 to 3, wherein the thickness of the anisotropic light-diffusing layer is 10 μm to 60 μm.

10. The anisotropic light-diffusing film according to any one of claims 1 to 3, wherein the thermoplastic elastomer is a photocurable compound.

11. The anisotropic light-diffusing film according to any one of claims 1 to 3, wherein the thermoplastic elastomer is a thermosetting compound, the composition further contains a curing agent, and the anisotropic light-diffusing layer is formed by photopolymerization plus thermal polymerization.

12. A film for displays, comprising the anisotropic light-diffusing film according to any one of claims 1 to 3, and an antiglare layer on the viewing side of the anisotropic light-diffusing layer.

13. The display film according to claim 12, wherein the antiglare layer has an arithmetic mean roughness of 0.05 μm to 1.00 μm.

14. A display comprising the display film according to claim 12, with the antiglare layer positioned on the most visible side.

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