Light-diffusing film, backlight unit, and liquid crystal display device

Abstract

The present invention provides a light-diffusing film that reduces the number of components in a backlight unit while maintaining basic optical properties such as light diffusion, light focusing, total light transmittance, and brightness, and also has excellent scratch resistance for the light-diffusing layer, as well as a backlight unit and an image display device module equipped with the light-diffusing film. [Solution] An example of a light-diffusing film comprises a transparent substrate and a cured film of a curable composition, the cured film having an irregular wrinkled uneven surface structure, the curable composition containing monofunctional (meth)acrylate, difunctional (meth)acrylate and trifunctional or more polyfunctional (meth)acrylate, the total proportion of monofunctional (meth)acrylate and difunctional (meth)acrylate being 50% by mass or less relative to the total mass of nonvolatile matter of the curable composition, the Sz of the wrinkled uneven structure being 4 μm or more, the Sv being 2.5 μm or more, and the haze of the film being 50% or more.

Description

[Technical Field]

[0001] The present invention relates to a light-diffusing film, a backlight unit, and a liquid crystal display device. More specifically, the present invention relates to a light-diffusing film that can isotropically diffuse light and can be used in various display devices such as organic electroluminescent (EL) displays and liquid crystal display (LCD) devices, a method for manufacturing the same, and a display device equipped with the film. [Background technology]

[0002] Light-diffusing films are widely used in lighting covers and image display devices (such as organic EL displays and liquid crystal displays). The optical properties required of such light-diffusing films include not only light diffusion to improve anti-glare properties by having high haze, but also high transparency (total light transmittance) and the ability to provide neutral white light to the viewer rather than yellow or red bias, thereby improving visibility. Furthermore, image display devices require high visibility in terms of image quality. For example, organic EL displays are prone to color unevenness due to variations in brightness between pixels, and there is a need for improvement of color unevenness (improvement of visibility) through the light-diffusing properties of light-diffusing films.

[0003] Conventional light-diffusing plates include those made by extruding or casting a composition of a transparent thermoplastic resin such as polymethyl methacrylate, MS resin, polycarbonate, or cyclic polyolefin mixed with a group of fine particles of silicone resin or acrylic resin. Light-diffusing plates diffuse light through the group of fine particles dispersed in the transparent thermoplastic resin.

[0004] Conventional light-diffusing films, for example, are made by directly coating the surface of a transparent film such as polyethylene terephthalate film with a composition in which a group of fine particles are kneaded into a light-transmitting resin. In light-diffusing films, in the light-diffusing layer, the group of fine particles completely embedded in the light-transmitting resin diffuses the light, and the group of fine particles partially protruding from the light-transmitting resin focuses the light in the forward direction. Furthermore, conventional prism sheets are made, for example, by uniformly and precisely molding a prism pattern of acrylic resin onto the surface of a polyester film.

[0005] However, as with conventional backlight units, a large number of components increases assembly costs. Also, light from the light source passes through many components before reaching the liquid crystal display panel. This results in light ray loss, reducing total light transmittance and brightness. Consequently, to improve brightness, it is necessary to increase the number of light sources or the power of the light sources. Furthermore, stacking multiple prism sheets or light-diffusing films to improve brightness can cause moiré patterns due to light interference between the sheets, degrading the image quality of the displayed image. Therefore, in the configuration of backlight units, there is a need to reduce the number of components and combine functions without reducing total light transmittance or brightness, and without causing light interference.

[0006] Attempts to reduce the number of components in a backlight unit or to combine functions include, for example, a method of attaching a light-diffusing film to a glass substrate that serves as a light-diffusing plate (for example, Patent Document 1), a method of using only a light-diffusing film held in a transparent member without using a light-diffusing plate (for example, Patent Document 2), a method of forming a row of prisms on the surface of a light-diffusing plate instead of a prism sheet (for example, Patent Document 3), a method of attaching a resin sheet having a three-dimensional pattern such as a prism shape to the surface of a light-diffusing plate (for example, Patent Document 4), and a method of providing a diffusion layer containing a diffuser between a light-receiving control layer and a light-distribution layer, which are composed of prism surfaces (for example, Patent Document 5).

[0007] However, the methods described in Patent Document 1 and Patent Document 2, respectively, either integrate a light diffuser plate and a light-diffusing film, or omit the diffuser plate, but sufficient diffused light cannot be obtained. Therefore, the shape of the light source cannot be completely eliminated, and a prism sheet is not used. As a result, there is a problem in that only low brightness can be obtained. Furthermore, the methods described in Patent Documents 3, 4, and 5, respectively, all involve integrating a light diffuser plate with a prism sheet, resulting in improved brightness and the complete elimination of the light source's shape. On the other hand, forming the prism shape and other components with high precision on an industrial scale is difficult, leading to increased manufacturing costs.

[0008] Attempts to improve the light diffusion and brightness of light-diffusing films are also being made. Examples of such attempts include a method of partially embedding a group of fine particles in a light-diffusing layer formed on a transparent substrate film, with some completely embedded and the rest partially embedded (e.g., Patent Document 6), a method of arranging spherical fine particles in a single layer on a translucent substrate (e.g., Patent Document 7), and a method of embedding micro-spherical lenses in a light-absorbing layer formed on a transparent support substrate (e.g., Patent Document 8).

[0009] However, the method described in Patent Document 6, while having excellent light diffusion properties, has few fine particles that partially protrude from the light diffusion layer. As a result, it has poor light focusing ability and can only produce low brightness. The methods described in Patent Documents 7 and 8, respectively, have excellent light focusing properties, but they only arrange spherical fine particles or microspherical lenses in a single layer. As a result, they have insufficient light diffusion ability and have the problem that the shape of the light source cannot be completely eliminated.

[0010] Incidentally, light-diffusing films equipped with a light-diffusing layer containing fine particles are susceptible to scratches during manufacturing, storage, transportation, and installation on displays due to friction between the protrusions of the light-diffusing layer and other components. For example, light-diffusing films are stored in roll form, during which the light-diffusing layer is strongly pressed against the opposing base film. This can cause scratches on both the light-diffusing film and the base film. Furthermore, when installed on a display, additional optical sheets such as light-diffusing films, prism sheets, or brightness-enhancing sheets may be placed on top of the light-diffusing film. In this case, the protrusions of the light-diffusing layer come into contact with the optical sheets, causing scratches on both the light-diffusing film and the optical sheets. Thus, when scratches occur on a light-diffusing film, its optical properties, such as light diffusion and total light transmittance, deteriorate.

[0011] Attempts to improve the scratch resistance of light-diffusing films include, for example, a method of incorporating crosslinked (meth)acrylic acid ester polymer fine particles with adjusted compressive strength and average particle size into the light-diffusing layer (for example, Patent Document 9), a method of incorporating resin particles with adjusted compressive strength and particulate lubricant into the light-diffusing layer (for example, Patent Document 10), and a method of providing a sticking prevention layer consisting of a resin layer containing a hard coat agent on the back surface of a substrate film on which a light-diffusing film is formed (for example, Patent Document 11).

[0012] However, in the method described in Patent Document 9, cross-linked (meth)acrylic acid ester polymer fine particles are coated with a transparent resin binder. As a result, the transparent resin binder coating the fine particles that partially protrude from the light-diffusing layer may peel off due to friction, etc. Furthermore, in the method described in Patent Document 10, particulate lubricants are used in addition to the resin particles of the light-diffusing agent. As a result, the light-diffusing properties of the light-diffusing layer may be reduced. Moreover, in the method described in Patent Document 11, the hardness of the anti-sticking layer is higher than that of the light-diffusing layer (pencil hardness 2H to 3H). As a result, even if scratches can be prevented from occurring on the back surface of the substrate film on which the light-diffusing layer is formed, there is a problem that scratches cannot be prevented from occurring on the light-diffusing layer. [Prior art documents]

Patent Document

[0013]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Patent Document 10

Patent Document 11

Summary of the Invention

Problems to be Solved by the Invention

[0014] The present invention provides a light-diffusing film that can reduce the members of a backlight unit while maintaining basic optical properties such as light diffusibility, light condensing property, total light transmittance, and luminance, and has excellent scratch resistance of the light-diffusing layer, a backlight unit provided with the light-diffusing film, and a liquid crystal display device.

Means for Solving the Problems

[0015] As a result of various studies, the inventors of the present invention have found that by defining parameters related to the curable resin constituting the light diffusion layer in a light-diffusing film or light-diffusing plate, and the surface irregularities of the light diffusion layer, the light-diffusing film or light-diffusing plate can independently possess high light diffusion and light-gathering properties. Therefore, as in the conventional technology, there is no need to use a light-diffusing film and a light-diffusing plate in combination, or to use a prism sheet. This allows for a reduction in the number of components while maintaining the basic optical properties of the backlight unit. Furthermore, by optimizing the composition of the curable resin, it has appropriate hardness and toughness, making it less susceptible to scratches on the light diffusion layer and contact components. Based on these findings, the inventors have completed the present invention.

[0016] The present invention has the following aspects. [1] comprising a transparent substrate and a cured film of a curable composition provided on the surface of the transparent substrate, The cured film has an irregular, wrinkled, uneven surface structure. The curable composition contains at least a monofunctional (meth)acrylate, a difunctional (meth)acrylate, and a polyfunctional (meth)acrylate with three or more functions. The total proportion of the monofunctional (meth)acrylate and the bifunctional (meth)acrylate is 50% by mass or less relative to the total mass of the nonvolatile content of the curable composition. The maximum distance Sz from the highest point to the lowest point of the uneven surface of the aforementioned irregular wrinkle-like uneven structure, as defined in ISO 25178, is 4 μm or more. The absolute value Sv of the minimum height from the mean surface of the irregular wrinkled surface as defined in ISO 25178 is 2.5 μm or more. A light-diffusing film with a haze of 50% or more. [2] The light-diffusing film according to [1], wherein the irregular wrinkled uneven structure is formed by curing the surface side of the coating film of the curable composition by irradiation with excimer light to form a cured film, and then curing the interior of the coating film by irradiation with active energy rays other than vacuum ultraviolet light, thereby causing the cured film on the surface side to buckle. [3] The light-diffusing film according to [1] or [2], wherein the curable composition may further contain particles, and the proportion of the particles is 0 to 30% by mass with respect to the total mass of the non-volatile components of the curable composition. [4] The light-diffusing film according to [3], wherein the average particle size of the particles is 0.01 to 30 μm. [5] The light-diffusing film according to any one of [1] to [4], wherein the 60° gloss of the surface of the cured film is 25 or less. [6] The light-diffusing film according to any one of [1] to [5], wherein the average value S5p of the heights of the five highest peak regions from the highest peak as defined in ISO 25178 of the uneven structure is 1.5 μm or more. [7] The void volume value Vvv in the valleys of the uneven structure at a load area ratio p% as defined in ISO 25178 is 0.03 ml / m 2 The above describes a light-diffusing film as described in any of [1] to [6]. [8] The light-diffusing film according to any one of [1] to [7], wherein the root mean square gradient Sdq of the coating surface having the irregular wrinkle-like uneven structure as defined in ISO 25178 is 0.1 or greater. [9] The light-diffusing film according to any one of [1] to [8], wherein the unfolded interface area ratio Sdr of the coating surface having an irregular wrinkle-like uneven structure as defined in ISO 25178 is 1% or more.

[10] The light-diffusing film according to any one of [1] to [9], wherein the transparent substrate is at least one selected from the group consisting of cycloolefin polymer film, polyethylene terephthalate film, polyacrylic polymer film and triacetylcellulose film.

[11] A backlight unit for illuminating liquid crystal display elements, provided in a liquid crystal display device, comprising a light source that generates light and a light-diffusing film disposed between the light source and the liquid crystal display elements, wherein the light-diffusing film is the light-diffusing film described in any of [1] to

[10] .

[12] A liquid crystal display device comprising a liquid crystal display element and a backlight unit for illuminating the liquid crystal display element, wherein the backlight unit is the backlight unit described in

[11] . [Effects of the Invention]

[0017] The light-diffusing film of the present invention can completely eliminate the shape of the light source and convert a linear light source into a surface light source. Therefore, while maintaining basic optical properties such as excellent light diffusion and focusing properties, and high total light transmittance and brightness, the number of components in the backlight unit can be reduced. Thus, backlight units and liquid crystal displays equipped with such a light-diffusing film can reduce the cost of various products using liquid crystal displays. Furthermore, the reduction in components reduces the loss of light rays passing between components. Therefore, the number of light sources can be reduced or the power of the light sources can be reduced. Moreover, the reduction in components prevents light interference between sheets. Therefore, the image quality of the displayed image is improved. In addition, the light-diffusing layer has excellent scratch resistance. Thus, the light-diffusing film of the present invention is easy to handle during manufacturing, storage, transportation, and use, and yield is improved. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of a light-diffusing film. [Figure 2] Figure 2 shows an example of an irregular, wrinkled, uneven structure. [Modes for carrying out the invention]

[0019] The following terms used in this specification have the following meanings: "(Meth)acrylate" is a general term for acrylates and methacrylates. The "~" symbol indicating a numerical range means that the numbers before and after it are included as the lower and upper limits. The numerical ranges disclosed herein can be combined in any way to form new numerical ranges.

[0020] Several embodiments will be described below with reference to the drawings. However, the following description concerns representative examples, and the present invention is not limited to those described below. The dimensional ratios in the drawings are for illustrative purposes only and may differ from those of the actual dimensions.

[0021] [Light-diffusing film] The light-diffusing film 1 illustrated in Figure 1 comprises a transparent substrate 3 and a cured film 2 provided on the surface of the transparent substrate 3. Although not shown in Figure 1, an irregular wrinkle-like uneven structure is formed on the surface 2a of the cured film 2.

[0022] An irregular, wrinkled, uneven structure is sometimes commonly referred to as a wrinkle structure. This irregular, wrinkled, uneven structure is a wave-like structure obtained by buckling of the surface layer, and refers to a labyrinthine structure such as the one shown in Figure 2.

[0023] (cured film) The cured film is a cured product of a curable composition that can be cured by irradiation with vacuum ultraviolet light. The curable composition contains at least monofunctional (meth)acrylate, difunctional (meth)acrylate, and polyfunctional (meth)acrylate with three or more functions.

[0024] Monofunctional (meth)acrylate: The curable composition may further contain a monofunctional (meth)acrylate having one unsaturated double bond in one molecule, from the viewpoint of adjusting viscosity and curing speed. Examples of monofunctional (meth)acrylates include alkyl (meth)acrylates such as methyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and methoxy Ethyl (meth)acrylate, ethoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, ethoxypropyl (meth)acrylate and other alkoxyalkyl (meth)acrylates, aromatic (meth)acrylates such as benzyl (meth)acrylate and phenoxyethyl (meth)acrylate, amino group-containing (meth)acrylates such as diaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, phenoxy polyethylene glycol Ethylene oxide-modified (meth)acrylates such as phenylphenol ethylene oxide-modified (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclopentyl (meth)acrylate, 1-methylcyclopentyl (meth)acrylate, 1-ethylcyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, 1-methylcyclohexyl (meth)acrylate, 1-ethylcyclohexyl (meth)acrylate , trimethylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, 2-cyclohexylpropanyl (meth)acrylate, 4-acryloylmorpholine, benzyl (meth)acrylate, phenyl (meth)acrylate, phenylalkylene oxide modified (meth)acrylate, nonylphenol (meth)acrylate, nonylphenol alkylene oxide modified (meth)acrylate, phenoxybenzyl (meth)acrylate, phenylbenzyl acrylate,Biphenyl (meth)acrylate, biphenyl alkylene oxide modified (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentanyl alkylene oxide modified (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl alkylene oxide modified (meth)acrylate, adamantyl (meth)acrylate, 2-methyladamantyl (meth)acrylate, 2-ethyladamantyl (meth)acrylate, 2-isopropyladamantyl Examples include (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (2-oxo-1,3-dioxolan-4-yl)methyl (meth)acrylate, mevalonate lactone (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, cyclic trimethylolpropaneformal (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and (meth)acrylic acid. These monofunctional (meth)acrylates can be used individually or in combination of two or more. Furthermore, among these monofunctional (meth)acrylates, cyclic (meth)acrylates are preferred considering the ease of forming a steep, uneven structure, and include monocyclic structures such as cyclopentane, cyclohexane, cyclooctane, and cyclodecane structures, as well as perhydroindene, perhydroanthracene, perhydrofluorene, perhydrophenanthrene, perhydroacenaphthene, perhydrophenalene, norbornane, isobornane, isobornyl, adamantane, and bi Polycyclic structures such as cyclo[3.3.0]octane, tricyclo[5.2.1.02,6]decane, tricyclo[6.2.1.02,7]undecane, dicyclopentanyl, dicyclopentenyl, tetrahydrofuran, 1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, hexahydroflu[3,2-b]furan, morpholine, benzene, biphenyl, naphthalene, fluorene, acenaphthene, phenalene, anthracene,(Meth)acrylates having phenanthrene, tetracene, chrysene, pyrene, triphenylene, pentacene, benzopyrene, or perylene structures are more preferred. Even more preferred are (meth)acrylates having one or more benzene rings, (meth)acrylates having condensed polycyclic hydrocarbons, (meth)acrylates having polycyclic structures such as dicyclopentenyl structures, (meth)acrylates having one or more benzene rings, (meth)acrylates having condensed polycyclic hydrocarbons, (meth)acrylates having polycyclic structures such as dicyclopentenyl structures, and (meth)acrylates having heterocyclic structures such as morpholine structures. Particularly preferred are biphenylalkylene oxide-modified (meth)acrylates, dicyclopentenylalkylene oxide-modified (meth)acrylates, and 4-acryloylmorpholine. However, monofunctional (meth)acrylates are not limited to these examples. Monofunctional (meth)acrylates may be used individually or in combination of two or more types.

[0025] The concentration of double bonds in the monofunctional (meth)acrylate is preferably 1.0 to 18 mmol / g, more preferably 1.5 to 17 mmol / g, even more preferably 2.0 to 16 mmol / g, and particularly preferably 3.0 to 15 mmol / g. When the concentration of double bonds in the monofunctional (meth)acrylate is within the above numerical range, the cured film exhibits excellent ease of surface irregularity formation.

[0026] Difunctional (meth)acrylate: A difunctional (meth)acrylate is a (meth)acrylate that has two unsaturated double bonds in one molecule. Examples of difunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,Alkane diol di(meth)acrylates such as 9-nonanediol di(meth)acrylate and tricyclodecanedimethylol di(meth)acrylate, bisphenol A ethylene oxide modified di(meth)acrylate and bisphenol F ethylene oxide modified di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, urethane di(meth)acrylate, epoxy di(meth)acrylate, hydrogenated bisphenol A di(meth)acrylate, hydrogenated bisphenol A Hydrogenated bisphenol-modified di(meth)acrylates such as lucilene oxide-modified di(meth)acrylate, hydrogenated bisphenol A caprolactone-modified di(meth)acrylate, hydrogenated bisphenol A glycidyl ether-modified di(meth)acrylate, hydrogenated bisphenol F di(meth)acrylate, hydrogenated bisphenol F caprolactone-modified di(meth)acrylate, hydrogenated bisphenol F alkylene oxide-modified di(meth)acrylate, hydrogenated bisphenol F glycidyl ether-modified di(meth)acrylate, and bisphenol A di(meth)acrylate. Acrylate, bisphenol A alkylene oxide modified di(meth)acrylate, bisphenol A caprolactone modified di(meth)acrylate, bisphenol A glycidyl ether modified di(meth)acrylate, bisphenol F di(meth)acrylate, bisphenol F caprolactone modified di(meth)acrylate, bisphenol F alkylene oxide modified di(meth)acrylate, bisphenol F glycidyl ether modified di(meth)acrylate, and other bisphenol modified di(meth)acrylates, full orange (meth) Examples include acrylate, fluorene alkylene oxide-modified di(meth)acrylate, isobornyl di(meth)acrylate, tricyclodecanediol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, adamantyl di(meth)acrylate, dioxaneglycol di(meth)acrylate, isosorbide di(meth)acrylate, isosorbide alkylene oxide-modified di(meth)acrylate, phenylglycidyl ether acrylate, hexamethylene diisocyanate urethane prepolymer, etc. Among these, considering the ease of forming an uneven structure, it is preferable that the alcohol residue has an unbranched structure, and among these, alkyldiol di(meth)acrylates and alkylene oxide-modified di(meth)acrylates are more preferred, and alkyldiol di(meth)acrylates having 4 to 18 carbon atoms are even more preferred. On the other hand, because urethane acrylate has low fluidity, if the mass ratio of urethane acrylate increases, it becomes less likely to create unevenness, and the low gloss effect due to the matte finish may not be achieved. However, difunctional (meth)acrylates are not limited to these examples. Difunctional (meth)acrylates may be used individually or in combination of two or more types.

[0027] The concentration of double bonds in the bifunctional (meth)acrylate is preferably 0.5 to 15 mmol / g, more preferably 1.0 to 13 mmol / g, even more preferably 1.5 to 12 mmol / g, and particularly preferably 2.0 to 10 mmol / g. When the concentration of double bonds in the bifunctional (meth)acrylate is within the above numerical range, it is easy to achieve both scratch resistance and durability of the cured film and ease of forming surface irregularities.

[0028] Multifunctional (meth)acrylate: Polyfunctional (meth)acrylates are (meth)acrylates that have three or more unsaturated double bonds in a single molecule. Examples of polyfunctional (meth)acrylates include dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol ethoxytetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxytri(meth)acrylate, dimethylolpropane tetra(meth)acrylate, and tripentaerythritol(meth)acrylate. However, polyfunctional (meth)acrylates are not limited to these examples. A single polyfunctional (meth)acrylate may be used alone, or two or more may be used in combination.

[0029] As polyfunctional (meth)acrylates, alkyl-modified (meth)acrylates, caprolactone-modified (meth)acrylates, ethylene oxide-modified (meth)acrylates, and propylene oxide-modified (meth)acrylates of the above-mentioned compounds may also be used. In addition, (meth)acrylates of aliphatic polyols and dendritic aliphatic compounds having acrylate groups at their terminals, known as dendrimers or hyperbranched polymers, are also useful. Commercially available dendritic aliphatic compounds having acrylate groups at their terminals include Viscoat V#1000, V#5020, and STAR-501 (manufactured by Osaka Organic Chemical Industry Co., Ltd.).

[0030] The concentration of double bonds in the polyfunctional (meth)acrylate is preferably 2.0 to 16 mmol / g, more preferably 3.0 to 15 mmol / g, even more preferably 4.0 to 14 mmol / g, and particularly preferably 5.0 to 12 mmol / g. When the concentration of double bonds in the polyfunctional (meth)acrylate is within the above numerical range, the cured film exhibits excellent scratch resistance and durability.

[0031] Urethane (meth)acrylate: The curable composition may contain urethane (meth)acrylate, which has a (meth)acryloyl group and a urethane bond in one molecule. Monofunctional urethane (meth)acrylate is classified as monofunctional (meth)acrylate, difunctional urethane (meth)acrylate as difunctional (meth)acrylate, and urethane (meth)acrylate with three or more functions as polyfunctional (meth)acrylate.

[0032] As the urethane (meth)acrylate, a urethane (meth)acrylate having two or more urethane bonds and two or more (meth)acryloyloxy groups in one molecule is preferred. For example, the following urethane (meth)acrylate (X) is preferred.

[0033] Urethane (meth)acrylate (X): A reaction product of a hydroxyl group-containing (meth)acrylate (x1), a polyisocyanate (x2), and a polyol (x3) having two or more hydroxyl groups in one molecule.

[0034] The hydroxyl group-containing (meth)acrylate (x1) is not particularly limited as long as it is a (meth)acrylate having a hydroxyl group and a (meth)acryloyloxy group. Examples include 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl acrylate (HPA), 2-hydroxypropyl methacrylate (HPMA), 2-hydroxybutyl acrylate (HBA), 4-hydroxybutyl acrylate (4-HBA), 2-hydroxybutyl methacrylate (HBMA), a 1 mol adduct of HEA to caprolactone (Praxel® FA1 from Daicel Corporation), a 2 mol adduct of HEA to caprolactone (Praxel FA2D), a 5 mol adduct of HEA to caprolactone (Praxel FA5), a 10 mol adduct of HEA to caprolactone (Praxel FA10L), and compounds whose skeleton is mono or polypentaerythritol.

[0035] Examples of compounds whose skeleton is mono- or polypentaerythritol include pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and dipentaerythritol penta(meth)acrylate. The hydroxyl group-containing (meth)acrylate (x1) may be used alone or in combination of two or more types.

[0036] Among the hydroxyl group-containing (meth)acrylates (x1), 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, pentaerythritol triacrylate, 1 mol caprolactone adduct of HEA manufactured by Daicel Corporation (Praxel FA1), and 2 mol caprolactone adduct of HEA (Praxel FA2D) are preferred from the viewpoint of ease of availability, reactivity, and solubility in curable compositions. 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate are more preferred, and 2-hydroxyethyl acrylate is even more preferred.

[0037] Polyisocyanate(x2) is not particularly limited as long as it is a polyisocyanate having two or more isocyanate groups in one molecule. For example, Aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), and lysine diisocyanate; Alicyclic polyisocyanates such as norbornane diisocyanate (NBDI), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis(isocyanate-methyl)cyclohexane (hydrogenated XDI), and dicyclohexylmethane diisocyanate (hydrogenated MDI); Aromatic polyisocyanates such as 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), tollidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), and triphenylmethane triisocyanate; These isocyanurate, adduct, and biuret compounds; These are some examples. Polyisocyanates (x2) may be used individually or in combination of two or more types.

[0038] From the viewpoint of weather resistance, aliphatic polyisocyanates and alicyclic polyisocyanates are preferred as polyisocyanates (x2), and hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), bis(isocyanate methyl)cyclohexane (hydrogenated XDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), isocyanurate of hexamethylene diisocyanate manufactured by Asahi Kasei Corporation (product name: Duranate TPA-100), adduct of hexamethylene diisocyanate (product name: Duranate P301-75E), biuret of hexamethylene diisocyanate (product name: Duranate 24A-100), and bifunctional type of hexamethylene diisocyanate (product name: Duranate A-201H) are more preferred. In particular, alicyclic polyisocyanates are more preferred from the viewpoint of scratch resistance, and dicyclohexylmethane diisocyanate (hydrogenated MDI) is even more preferred.

[0039] Polyol(x3) is not particularly limited as long as it is a polyol having two or more hydroxyl groups in one molecule. Examples include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, polycaprolactone polyol (polycaprolactone diol, etc.), polytetramethylene ether glycol (PTMG), polycarbonate polyol (polycarbonate diol, etc.), and lactone polyol (4-hydroxy-N-(2-hydroxyethyl)-N-methylbutanamide, obtained by reacting γ-butyrolactone with N-methylethanolamine, etc.). In particular, from the viewpoint of weather resistance, polycaprolactone polyol, polycarbonate polyol, and lactone-based polyol are preferred, with polycarbonate polyol being more preferred. Furthermore, from the viewpoint of improving the flexibility of the cured film and making it less prone to cracking, polyoxyethylene glycol, polyoxybutylene glycol, and polytetramethylene ether glycol (PTMG) are preferred, with polytetramethylene ether glycol being more preferred. Polyol (x3) may be used individually or in combination of two or more types.

[0040] A commercially available polyol (x3) may be used. Examples of commercially available polycarbonate polyols include, Kuraray Polyol C-590, Kuraray Polyol C-770, Kuraray Polyol C-1050, Kuraray Polyol C-1090, Kuraray Polyol C1065N, Kuraray Polyol C-1015N, Kuraray Polyol C-2090, and Kuraray Polyol C-3090, all manufactured by Kuraray Co., Ltd. Duranol T-5650E, Duranol T-5650J, Duranol T-5651, Duranol T-5652, Duranol G-4671, Duranol G-4672, Duranol G3450J, Duranol G3452, all manufactured by Asahi Kasei Corporation; Beneviol NL1010DB, Beneviol NL2010DB, Beneviol NL3010DB, Beneviol NL1005B, Beneviol NL2005B, Beneviol NL1030B, Beneviol HS0830B, Beneviol HS0840B, Beneviol HS0840H, Beneviol HS0850H, all manufactured by Mitsubishi Chemical Corporation. These are some examples.

[0041] Examples of commercially available polytetramethylene ether glycols include, PTMG250, PTMG650, PTMG1000, PTMG2000, PTMG3000, manufactured by Mitsubishi Chemical Corporation; PTMEG #220, PTMEG #650, PTMEG #1000, PTMEG #1400, PTMEG #2000 manufactured by Mihama Co., Ltd. PTG-650, PTG-850SN, and PTG-3000, manufactured by Hodogaya Chemical Co., Ltd. These are some examples.

[0042] Urethane (meth)acrylate (x1) is obtained by reacting a hydroxyl group-containing (meth)acrylate (x1), a polyisocyanate (x2), and a polyol (x3). The reaction conditions are preferably under heating. For example, a reaction temperature of 70°C for a reaction time of 8 hours is one possible condition.

[0043] For example, urethane (meth)acrylate (x1) is, Reaction product of a polycarbonate polyol, a diisocyanate compound having an alicyclic structure, and a (meth)acrylate monomer having a hydroxyl group; A reaction product of polytetramethylene ether glycol, 4-hydroxy-N-(2-hydroxyethyl)-N-methylbutanamide, a diisocyanate compound having an alicyclic structure, and a (meth)acrylate monomer having a hydroxyl group; It is preferable.

[0044] The number of (meth)acryloyl functional groups in the urethane (meth)acrylate is preferably 2 to 15, more preferably 2 to 10, even more preferably 2 to 6, particularly preferably 2 to 4, and most preferably 2. When the number of (meth)acryloyl functional groups in the urethane (meth)acrylate is within the above numerical range, the scratch resistance is improved.

[0045] The double bond group concentration of urethane (meth)acrylate is preferably 0.1 to 15 mmol / g, more preferably 0.2 to 10.0 mmol / g, even more preferably 0.3 to 7.0 mmol / g, and particularly preferably 0.4 to 5.0 mmol / g. When the double bond group concentration of urethane (meth)acrylate is within the above numerical range, the cured film exhibits excellent adhesion and durability to the substrate. Here, the double bond group concentration refers to the concentration of (meth)acryloyl groups and allyl groups in the urethane (meth)acrylate, that is, the amount of (meth)acryloyl groups and allyl groups introduced.

[0046] The urethane (meth)acrylate preferably has polyol-derived structural units with a number average molecular weight of 500 or more. These polyol-derived structural units contribute to the adhesion, flexibility, and handling properties of the cured product due to its viscosity. The urethane (meth)acrylate may further have polyol-derived structural units with a number average molecular weight of less than 500.

[0047] The weight-average molecular weight of the urethane (meth)acrylate is preferably 1,000 or more, more preferably 1,300 or more, and even more preferably 1,500 or more. When the weight-average molecular weight of the urethane (meth)acrylate is above the lower limit, the flexibility and adhesion of the cured product are easily enhanced. The upper limit of the weight-average molecular weight of urethane (meth)acrylate is not particularly limited, but from the viewpoint of workability due to viscosity, it is preferably 100,000 or less, more preferably 75,000 or less, and even more preferably 50,000 or less. When the weight-average molecular weight of urethane (meth)acrylate is below the above upper limit, it has low viscosity and good handling properties, and the cured product has excellent scratch resistance. The lower and upper limits of the weight-average molecular weight of the urethane (meth)acrylate can be arbitrarily combined. For example, 1,000 to 100,000 is preferred, 1,300 to 75,000 is more preferred, and 1,500 to 50,000 is even more preferred.

[0048] On the other hand, because urethane acrylate has low fluidity, if the mass ratio of urethane acrylate increases, it becomes less likely to create unevenness, and the low gloss effect due to the matte finish may not be achieved.

[0049] The aforementioned acrylic acrylate refers to an acrylic resin into which (meth)acrylate has been introduced by the following methods. For example, methods for introducing the double bond include reacting an acrylic resin having an epoxy group with (meth)acrylate and a compound having a carboxyl group (Method 1), reacting an acrylic resin having a carboxyl group with (meth)acrylate and a compound having an epoxy group (Method 2), reacting an acrylic resin having a hydroxyl group with (meth)acrylate and a compound having a carboxyl group (Method 3), reacting an acrylic resin having a carboxyl group with (meth)acrylate and a compound having a hydroxyl group (Method 4), reacting an acrylic resin having an isocyanate group with (meth)acrylate and a compound having a hydroxyl group (Method 5), and reacting an acrylic resin having a hydroxyl group with (meth)acrylate and a compound having an isocyanate group (Method 6).

[0050] In Method 1 described above, examples of vinyl monomers having epoxy groups used to obtain an acrylic resin having epoxy groups include glycidyl (meth)acrylate, 3,4-epoxycyclohexyl (meth)acrylate, and 3,4-epoxycyclohexylmethyl (meth)acrylate. Among these, glycidyl (meth)acrylate is particularly preferred, and glycidyl methacrylate is especially preferred, considering its good reactivity and ease of use. These may be used individually or in combination of two or more.

[0051] Furthermore, examples of compounds having (meth)acrylate and carboxyl groups in Method 1 include (meth)acrylic acid, carboxyethyl (meth)acrylate, adducts of glycerin di(meth)acrylate and succinic anhydride, adducts of pentaerythritol tri(meth)acrylate and succinic anhydride, and adducts of pentaerythritol tri(meth)acrylate and phthalic anhydride. Among these, (meth)acrylic acid and adducts of pentaerythritol tri(meth)acrylate and succinic anhydride are preferred, (meth)acrylic acid is more preferred, and acrylic acid is even more preferred. Only one compound having (meth)acrylate and carboxyl groups may be used, or two or more may be combined.

[0052] In Method 2 described above, examples of carboxyl-group-containing (meth)acrylates used to obtain an acrylic resin containing carboxyl groups include (meth)acrylic acid, carboxyethyl (meth)acrylate, and polybasic acid-modified (meth)acrylate. Among these, (meth)acrylic acid is preferred, and acrylic acid is more preferred. These may be used individually or in combination of two or more.

[0053] Furthermore, in Method 2 described above, examples of compounds having (meth)acrylate and epoxy groups include glycidyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate glycidyl ether. Among these, glycidyl (meth)acrylate is preferred. These may be used individually or in combination of two or more.

[0054] In method 3 described above, examples of hydroxyl-containing (meth)acrylates used to obtain an acrylic resin containing hydroxyl groups include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and hydroxypropyl (meth)acrylate. These may be used individually or in combination of two or more.

[0055] Furthermore, in Method 3, the compound having (meth)acrylate and carboxyl groups can be the same as the compound in Method 1.

[0056] In method 4, the acrylic resin having a carboxyl group can be the same as that used in method 2.

[0057] Furthermore, in method 4 described above, examples of compounds having (meth)acrylate and hydroxyl groups include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and hydroxypropyl (meth)acrylate. These may be used individually or in combination of two or more.

[0058] In the above method 5, examples of vinyl monomers having isocyanate groups used to obtain an acrylic resin having isocyanate groups include isocyanate ethyl (meth)acrylate.

[0059] Furthermore, in Method 5, the compound having (meth)acrylate and a hydroxyl group can be, for example, the same compound as those listed in Method 4.

[0060] In method 6 described above, the acrylic resin having a hydroxyl group can be the same as the compound used in method 3 described above.

[0061] Furthermore, in method 6 described above, examples of compounds having (meth)acrylate and isocyanate groups include isocyanate ethyl (meth)acrylate. These may be used individually or in combination of two or more.

[0062] Among the above methods, Method 1 is preferred from the viewpoint of ease of controlling the reaction. In Method 1, (meth)acrylate is introduced by a ring-opening and addition reaction between the epoxy group of the acrylic resin having an epoxy group and the carboxyl group in the (meth)acrylate and the compound having a carboxyl group.

[0063] In Method 1 described above, the monomers having epoxy groups in the acrylic resin having epoxy groups are preferably in the range of 5% by weight or more, more preferably 10% by weight or more, and even more preferably 15% by weight or more, of the total amount of monomers constituting the acrylic resin having epoxy groups. There is no particular upper limit, but 99.9% by weight or less is preferred. By using this range, not only are the adhesion, scratch resistance, and hardness of the cured film to the substrate improved, but the uneven surface shape tends to become finer, and it is possible to achieve a decrease in Rsm, a decrease in Ra, and in some cases an increase in haze and a decrease in gloss.

[0064] Furthermore, in Method 1 described above, the (meth)acrylate and the compound having a carboxyl group are preferably in the proportion of the compound having a double bond and a carboxyl group relative to the epoxy groups in the acrylic resin having epoxy groups, which is 10 to 150 mol%, more preferably 30 to 130 mol%, and even more preferably 50 to 110 mol%. Using this range is preferable from the viewpoint of allowing the reaction to proceed without excess or deficiency, and of reducing the amount of raw material residue.

[0065] Furthermore, acrylic resins, such as the acrylic resin having the epoxy group described above, may also be copolymers of (meth)acrylates or other vinyl monomers other than those described above. The polymerization reaction of these raw materials is usually radical polymerization and can be carried out under conventionally known conditions.

[0066] Monomers that can be used in combination as raw materials include (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, methoxy (poly)ethylene glycol (meth)acrylate, methoxy (poly)propylene glycol (meth)acrylate, methoxy (poly)ethylene glycol (poly)propylene glycol (meth)acrylate, octoxy (poly)ethylene glycol (meth)acrylate, octoxy (poly)propylene glycol (meth)acrylate, octoxytetramethylene glycol (meth)acrylate, lauroxy (poly)ethylene glycol (meth)acrylate, and stearoxy (poly)ethylene glycol (meth)acrylate; Acrylamides such as ethyl(meth)acrylamide, n-butyl(meth)acrylamide, i-butyl(meth)acrylamide, t-butyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N-hydroxypropyl(meth)acrylamide, and N,N-dihydroxyethyl(meth)acrylamide; Examples include styrene, p-chlorostyrene, p-bromostyrene, and other styrene-based monomers. These may be used individually or in combination of two or more.

[0067] Acrylic resins can be produced by radical polymerization using the above-mentioned vinyl monomer raw materials. The radical polymerization reaction is preferably carried out in an organic solvent in the presence of a radical polymerization initiator.

[0068] Examples of organic solvents used in radical polymerization include ketone solvents such as acetone and methyl ethyl ketone (MEK); alcohol solvents such as ethanol, methanol, isopropyl alcohol (IPA), and isobutanol; ether solvents such as ethylene glycol dimethyl ether and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, propylene glycol monomethyl ether acetate, and 2-ethoxyethyl acetate; and aromatic hydrocarbon solvents such as toluene. These organic solvents may be used individually or in combination of two or more.

[0069] Examples of radical polymerization initiators used in radical polymerization include organic peroxides such as benzoyl peroxide and di-t-butyl peroxide; and azo compounds such as 2,2'-azobisbutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). These radical polymerization initiators may be used individually or in combination of two or more.

[0070] It is preferable to use a radical polymerization initiator in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the total amount of monomers in the raw materials.

[0071] Furthermore, during radical polymerization, chain transfer agents can be used to control the weight-average molecular weight of the acrylic resin. Examples of chain transfer agents include butanethiol, octanthiol, decanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, cyclohexyl mercaptan, thiophenol, octyl thioglycolate, octyl 2-mercaptopropionate, octyl 3-mercaptopropionate, 2-ethylhexyl mercaptopropionate, 2-ethylhexyl thioglycolate, butyl-3-mercaptopropionate, mercaptopropyltrimethoxysilane, methyl-3-mercaptopropionate, and 2,2-(ethylenedi Examples of thiol compounds include oxy)diethanethiol, ethanethiol, 4-methylbenzenethiol, 2-mercaptoethyl octanoate, 1,8-dimercapto-3,6-dioxaoctane, decantrithiol, dodecyl mercaptan, diphenyl sulfoxide, dibenzyl sulfide, 2,3-dimethylcapto-1-propanol, mercaptoethanol, thiosalicylic acid, thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, thiomalic acid, mercaptoacetic acid, mercaptosuccal acid, and 2-mercaptoethanesulfonic acid. These may be used individually or in combination of two or more.

[0072] The amount of chain transfer agent used is preferably 0.1 to 25 parts by weight, more preferably 0.5 to 20 parts by weight, and even more preferably 1.0 to 15 parts by weight, per 100 parts by weight of the total amount of monomers of the raw materials.

[0073] The reaction time for radical polymerization is preferably 1 to 20 hours, and more preferably 3 to 12 hours. The reaction temperature is preferably 40 to 120°C, and more preferably 50 to 100°C.

[0074] To react an acrylic resin with a compound having (meth)acrylate and a carboxyl group, the acrylic resin obtained as described above is to be reacted with the compound having (meth)acrylate and a carboxyl group, and the reaction is carried out at a temperature of usually 90 to 140°C, preferably 100 to 120°C, for usually 3 to 9 hours in the presence of one or more catalysts such as triphenylphosphine, tetrabutylammonium bromide, tetramethylammonium chloride, and triethylamine. Here, it is preferable to use the catalyst in a ratio of about 0.5 to 3 parts by weight per 100 parts by weight of the total of the raw material (meth)acrylic acid ester polymer and the compound having (meth)acrylate and a carboxyl group. This reaction may be carried out immediately after producing the acrylic resin by polymerization, or the acrylic resin may be separated from the reaction system first, and then the compound having (meth)acrylate and a carboxyl group may be added.

[0075] The amount of double bonds in the acrylic resin is preferably in the range of 0.1 to 20 mmol / g, more preferably 0.2 to 15 mmol / g, even more preferably 0.5 to 10 mmol / g, particularly preferably 0.8 to 8.0 mmol / g, and most preferably 1.0 to 5.0 mmol / g. Using this range not only improves the adhesion, scratch resistance, and hardness of the cured film to the substrate, but also tends to refine the uneven surface shape, achieving a decrease in Rsm, a decrease in Ra, and in some cases an increase in haze and a decrease in gloss. The amount of double bonds referred to here means the concentration of (meth)acryloyl groups in the acrylic resin, that is, the amount of (meth)acryloyl groups introduced.

[0076] The weight-average molecular weight (Mw) of the acrylic resin should be appropriately selected depending on the application of the curable composition, but is usually 5,000 or more, preferably 7,000 or more, more preferably 9,000 or more, usually 200,000 or less, preferably 100,000 or less, more preferably 70,000 or less, and even more preferably 50,000 or less. Within the above range, surface irregularities are easily formed. The weight-average molecular weight (Mw) of the resin can be determined as a converted value using polystyrene standards by gel permeation chromatography (GPC). Specific measurement conditions are shown in the examples below.

[0077] The curable composition may also use curable compounds other than (meth)acrylates that can be cured by irradiation with vacuum ultraviolet light. Examples include vinyl compounds such as styrene, vinyl halides, and vinyl acetate, and diene compounds such as vinylidene halides, 1,3-butadiene, isoprene, and chloroprene.

[0078] particle: The curable composition may further contain particles in addition to monofunctional (meth)acrylate, difunctional (meth)acrylate, and polyfunctional (meth)acrylate. The particles may be inorganic particles or organic particles, and are not particularly limited. The particles may be surface-modified with a silane coupling agent having a reactive group such as a (meth)acryloyl group. The organic particles may be crosslinked particles.

[0079] Examples of inorganic particles include aluminum oxide, silica, zirconia, titania, hollow silica particles, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, zirconium oxide, and titanium dioxide. However, inorganic particles are not limited to these examples. One type of inorganic particle may be used alone, or two or more types may be used in combination.

[0080] Examples of organic particles include polymethyl methacrylate particles, acrylic-styrene copolymer particles, melamine resin particles, urea resin particles, phenolic resin particles, epoxy resin particles, polycarbonate particles, polystyrene particles, polyvinyl chloride particles, benzoguanamine-melamine-formaldehyde condensate particles, silicone particles, fluororesin particles, and polyester resin particles. However, the organic particles are not limited to these examples. One type of organic particle may be used alone, or two or more types may be used in combination.

[0081] The average particle size is preferably 0.01 to 30 μm, more preferably 0.05 to 10 μm, even more preferably 0.1 to 5 μm, and particularly preferably 0.5 to 3 μm. When the average particle size is above the lower limit of the above numerical range, a light-diffusing film exhibiting good quality matte finish is more likely to be obtained. When the average particle size is below the upper limit of the above numerical range, a light-diffusing film with suppressed haze and improved light transmittance is more likely to be obtained. The average particle size is the 50% cumulative value of the volume-based particle size distribution measured using a particle size distribution analyzer.

[0082] Photopolymerization initiator: The curable composition may further contain a photopolymerization initiator. Examples of photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin phenyl ether, benzyl diphenyl disulfide, dibenzyl, diacetyl, anthraquinone, naphthoquinone, 3,3'-dimethyl-4-methoxybenzophenone, benzophenone, p,p'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, pivaloin ethyl ether, benzyl dimethyl ketal, 1,1-dichloroacetophenone, and pt-butyldichloro Examples include acetophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-diethylthioxanthone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-dichloro-4-phenoxyacetophenone, phenylglyoxylate, α-hydroxyisobutylphenone, dibenzosparone, 1-(4-isopropylphenyl)-2-hydroxy-2-methyl-1-propanone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propanone, tribromophenylsulfone, and tribromomethylphenylsulfone. However, photopolymerization initiators are not limited to these examples. One type of photopolymerization initiator may be used alone, or two or more types may be used in combination.

[0083] Organic solvents: The curable composition may further contain an organic solvent. Examples of organic solvents include aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone; ether solvents such as diethyl ether, isopropyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, anisole, and phenethole; ester solvents such as ethyl acetate, butyl acetate, isopropyl acetate, and ethylene glycol diacetate; amide solvents such as dimethylformamide, diethylformamide, and N-methylpyrrolidone; cellosolve solvents such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; alcohol solvents such as methanol, ethanol, propanol, isopropanol, and butanol; and halogen solvents such as dichloromethane and chloroform. However, organic solvents are not limited to these examples. One organic solvent may be used alone, or two or more may be used in combination.

[0084] Composition of the curable composition: The composition of the curable composition is not particularly limited, as long as the total proportion of monofunctional (meth)acrylate and difunctional (meth)acrylate is 50% by mass or less relative to the total mass of the nonvolatile content of the curable composition. The nonvolatile content of the curable composition can be measured as the amount of residue when the curable composition is heated at 100°C for 1 hour.

[0085] The proportion of monofunctional (meth)acrylate is preferably 0 to 99% by mass, more preferably 0 to 70% by mass, even more preferably 0 to 50% by mass, and particularly preferably 0 to 30% by mass, relative to the total mass of nonvolatile components of the curable composition. When the proportion of monofunctional (meth)acrylate is above the lower limit of the above numerical range, a light-diffusing film is obtained that offers improved workability due to low viscosity and easily achieves the desired matte and gloss properties. When the proportion of monofunctional (meth)acrylate is below the upper limit of the above numerical range, a light-diffusing film with improved scratch resistance and durability is easily obtained.

[0086] The proportion of the bifunctional (meth)acrylate is preferably 0 to 99% by mass, more preferably 5 to 90% by mass, even more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass, relative to the total mass of nonvolatile components of the curable composition. When the proportion of the bifunctional (meth)acrylate is above the lower limit of the above numerical range, a light-diffusing film is obtained that offers improved workability due to low viscosity and easily achieves the desired matte and gloss properties. When the proportion of the bifunctional (meth)acrylate is below the upper limit of the above numerical range, a light-diffusing film with improved scratch resistance and durability is easily obtained.

[0087] The proportion of polyfunctional (meth)acrylate is preferably 1 to 99% by mass, more preferably 10 to 90% by mass, even more preferably 20 to 85% by mass, and particularly preferably 30 to 80% by mass, relative to the total mass of nonvolatile components of the curable composition. When the proportion of polyfunctional (meth)acrylate is above the lower limit of the above numerical range, a light-diffusing film with improved scratch resistance and durability is easily obtained. When the proportion of polyfunctional (meth)acrylate is below the upper limit of the above numerical range, a light-diffusing film with improved workability due to low viscosity and that easily achieves the desired matte and gloss properties can be obtained.

[0088] The proportion of urethane (meth)acrylate or acrylic (meth)acrylate is preferably 0 to 99% by mass, more preferably 0 to 90% by mass, even more preferably 0 to 85% by mass, and particularly preferably 0 to 80% by mass, relative to the total mass of nonvolatile matter of the curable composition. If the proportion of urethane (meth)acrylate or acrylic (meth)acrylate is above the lower limit of the above numerical range, it is easier to obtain an anti-glare film with excellent processability and easy control of the size of irregularities. If the proportion of urethane (meth)acrylate or acrylic (meth)acrylate is below the upper limit of the above numerical range, it is easier to obtain a light-diffusing film with excellent scratch resistance and durability.

[0089] The particle ratio is preferably 0 to 30% by mass, more preferably 0.1 to 20% by mass, even more preferably 1 to 15% by mass, and particularly preferably 3 to 10% by mass, relative to the total mass of nonvolatile components of the curable composition. When the particle ratio is above the lower limit of the above numerical range, it is possible to form a high-quality surface texture and obtain an anti-glare film that is easy to control haze and gloss. When the particle ratio is below the upper limit of the above numerical range, it is possible to obtain an anti-glare film with excellent scratch resistance and durability.

[0090] The proportion of the photopolymerization initiator is not particularly limited. It can be appropriately changed considering the curing rate of each component. For example, the proportion of the photopolymerization initiator may be 0.1 to 20% by mass, 0.5 to 10% by mass, or 1 to 8% by mass, relative to the total mass of the nonvolatile content of the curable composition.

[0091] The proportion of the organic solvent is not particularly limited. It can be appropriately changed considering viscosity and workability during application. The proportion of the organic solvent is preferably 10 to 1900 parts by mass, and more preferably 40 to 400 parts by mass, per 100 parts by mass of the nonvolatile content of the curable composition. If the organic solvent content is within the above range, the workability during application of the curable composition will be improved.

[0092] (Transparent base material) The transparent substrate is not particularly limited as long as its total light transmittance is 50% or more. For example, various polymer films, polymer plates, and polymer molded products can be used. The resin substrate may be a single layer or a multilayer structure of two or more layers, and is not particularly limited. If necessary, glass or the like can be used as the transparent substrate. Total light transmittance is a value measured in accordance with JIS Z 8722:2009 (Measurement method for transparent objects: Geometric conditions for irradiation and reception) and JIS K 7361-1:1997 (Plastics - Test method for total light transmittance of transparent materials).

[0093] Examples of resin films include triacetylcellulose (TAC) film, polyethylene terephthalate (PET) film, diacetylene cellulose film, acetate butyrate cellulose film, polyethersulfone film, polyacrylic polymer film, polyurethane polymer film, polycarbonate film, polysulfone film, polyether film, polymethylpentene film, polyether ketone film, (meth)acrylonitrile film, cycloolefin polymer (COP) film, stretched polypropylene film, and unstretched polypropylene film. Among these, COP film, PET film, polyacrylic polymer film, and TAC film are preferred from the viewpoint of minimizing phase difference. In the case of PET film, it is preferable to have a zero retardation film with an in-plane retardation of 100 nm or less, particularly 50 nm or less, or a high retardation film with a retardation of 3000 nm to 30000 nm.

[0094] Examples of polymer plates and polymer molded products include acrylic plates, triacetylcellulose plates, polyethylene terephthalate plates, diacetylene cellulose plates, acetate butyrate cellulose plates, polyethersulfone plates, polyurethane plates, polycarbonate plates, polysulfone plates, polyether plates, polymethylpentene plates, polyetherketone plates, (meth)acrylonitrile plates, and the like.

[0095] The thickness of the transparent substrate can be selected as appropriate depending on the application. The thickness of the transparent substrate may be approximately 2 to 10,000 μm, approximately 5 to 1,000 μm, or approximately 10 to 250 μm.

[0096] (Properties of light-diffusing films) The maximum distance Sz from the highest point to the lowest point of the uneven surface, as defined by ISO 25178, is 4 μm or more, preferably 5 μm or more, more preferably 5.3 μm or more, and even more preferably 5.5 μm or more. When the maximum distance Sz is equal to or greater than the lower limit, an anti-glare film is obtained that easily achieves the desired matte finish and glossiness. The upper limit of the maximum distance Sz is not particularly limited, but it may be, for example, 30 μm, 20 μm, or 15 μm.

[0097] The absolute value Sv of the minimum height from the mean surface of the uneven surface, as defined in ISO 25178 for the irregular wrinkle-like uneven structure, is 2.5 μm or more, preferably 2.8 μm or more. When the absolute value Sv is above the lower limit, there are many high irregularities, and an anti-glare film that easily achieves the desired matte and gloss properties can be obtained. The upper limit of the absolute value Sv is not particularly limited, but it may be, for example, 15 μm, 10 μm, or 8 μm.

[0098] The arithmetic mean roughness Ra of the roughness curve element conforming to JIS B0601:2013, which has an irregular wrinkle-like uneven structure, is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably 0.7 μm or more. When the arithmetic mean roughness Ra is above the aforementioned lower limit, a light-diffusing film with improved scratch resistance is more likely to be obtained. The upper limit of the average roughness Ra is not particularly limited, but from the viewpoint of matte finish, it may be, for example, 3 μm, 2 μm, or 1.2 μm.

[0099] The average length Rsm of the roughness curve elements conforming to JIS B0601:2013, which have an irregular wrinkle-like uneven structure, is preferably 20 to 200 μm, more preferably 25 to 150 μm, and even more preferably 30 to 100 μm. If the average length Rsm is above the lower limit of the above numerical range, it is easier to achieve the desired matte finish, and at the same time, the unevenness is less likely to be abraded, making it easier to obtain a scratch-resistant and anti-glare film. If the average length Rsm is below the upper limit of the above numerical range, it is easier to obtain a light-diffusing film with improved matte finish.

[0100] The inclination angle θα of the roughness curve element conforming to JIS B0601:2013, which has an irregular wrinkle-like uneven structure, is preferably 4° or more, more preferably 5° or more, and even more preferably 6° or more. When the inclination angle θα is above the lower limit, an anti-glare film that easily achieves the desired matte finish and gloss can be obtained. The upper limit of the inclination angle θα is not particularly limited, but from the perspective of matte finish, it may be 20°, 15°, or 12°.

[0101] The haze of the light-diffusing film is 50% or more, preferably 55% or more, more preferably 58% or more, and even more preferably 60% or more. When the haze of the light-diffusing film is above the lower limit, a light-diffusing film with improved light-diffusing properties is more likely to be obtained. The upper limit of the haze of a light-diffusing film is not particularly limited, but from the viewpoint of matte finish, it may be, for example, 99%, 97%, or 95%.

[0102] The 60° gloss of the surface of the cured film is preferably 25 or less, more preferably 20 or less, and even more preferably 17 or less. When the 60° gloss of the surface of the cured film is below the above upper limit, an anti-glare film that easily achieves the desired matte and gloss properties can be obtained. The lower limit of the 60° gloss on the surface of the cured film is not particularly limited, but may be, for example, 1, 3, or 5.

[0103] The 20° gloss of the surface of the cured film is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. When the 20° gloss of the surface of the cured film is below the above upper limit, an anti-glare film that easily achieves the desired matte finish and gloss can be obtained. The lower limit of the 20° gloss on the surface of the cured film is not particularly limited, but may be, for example, 0.1, 0.5, or 0.8.

[0104] The average value S5p of the peak regions from the highest peak to the fifth highest peak, as defined in ISO 25178, for the irregular wrinkle-like uneven structure is preferably 1.5 μm or more, more preferably 2.0 μm or more, and even more preferably 2.5 μm or more. When the average value S5p is above the lower limit, an anti-glare film that easily achieves the desired matte and gloss properties can be obtained. While there is no particular upper limit to the average value S5p, from the perspective that scratch resistance tends to deteriorate due to high surface irregularities, it may be, for example, 15 μm, 10 μm, or 5 μm.

[0105] The void volume value Vvv in the valleys of an irregular, wrinkled, uneven structure at a load area ratio of p% as defined by ISO 25178 is 0.03 ml / m 2 The above is preferable, and 0.05 ml / m 2 The above is more preferable, 0.1 ml / m 2 The above is even more preferable. When the void volume value Vvv is greater than or equal to the lower limit, an anti-glare film can be obtained that easily achieves the desired matte finish and glossiness. There is no particular upper limit to the void volume value Vvv, but for example, 0.5 ml / m 2 It may also be 0.3 ml / m 2 It may also be 0.2 ml / m 2 That's fine.

[0106] The root mean square gradient Sdq of the coating surface, defined by ISO 25178, which has an irregular wrinkle-like uneven structure, is preferably 0.1 or higher, more preferably 0.15 or higher, and even more preferably 0.2 or higher. When the root mean square gradient Sdq is above the lower limit, an anti-glare film that easily achieves the desired matte finish and gloss can be obtained. The upper limit of the root mean square gradient Sdq is not particularly limited; for example, it could be 1.0, 0.8, or 0.6.

[0107] The unfolded interface area ratio Sdr of the coating surface, defined by ISO 25178, which has an irregular wrinkle-like uneven structure, is preferably 1% or more, more preferably 1.5% or more, and even more preferably 2% or more. When the unfolded interface area ratio Sdr is above the lower limit, an anti-glare film that easily achieves the desired matte finish and gloss can be obtained. The upper limit of the expanded interface area ratio Sdr is not particularly limited, but it may be, for example, 30%, 20%, or 15%.

[0108] (Method for manufacturing light-diffusing film) The light-diffusing film is obtained by applying a curable composition to a transparent substrate, removing the solvent by hot air drying, and then irradiating it with vacuum ultraviolet light. The irregular, wrinkled, uneven structure is thought to appear as a result of the curing of the surface of the cured film, which hardens first when the curable composition hardens, forming a cured film, and then shrinking stress during the hardening of the interior of the cured film causing the surface cured film to shrink.

[0109] An example of a method for forming an irregular, wrinkled, uneven structure is as follows: After curing the surface of a coating film of a curable composition by irradiation with excimer light to form a cured film, the interior of the coating film is cured by irradiation with active energy rays other than vacuum ultraviolet light, causing the cured film on the surface to buckle. In this way, an irregular, wrinkled, uneven structure can be formed.

[0110] Irregular wrinkled, uneven structures can be made smaller by increasing the intensity of vacuum ultraviolet irradiation and shortening the curing time of the curable composition, while larger wrinkled structures can be made by decreasing the intensity of vacuum ultraviolet irradiation and lengthening the curing time of the curable composition.

[0111] Irregular wrinkled surface can be made smaller by increasing the viscosity of the curable composition (excluding the solvent) and reducing its fluidity. Conversely, a larger irregular wrinkled surface can be made by decreasing the viscosity of the curable composition (excluding the organic solvent) and improving its fluidity.

[0112] Examples of the atmosphere when curing the curable composition include inert gases such as air, nitrogen, carbon dioxide, and argon. From the viewpoints of practicality and economy, air, nitrogen, and carbon dioxide are preferred. In addition, as the atmosphere during vacuum ultraviolet irradiation, it is preferably carried out in an environment with less oxygen such as under a nitrogen atmosphere. The oxygen concentration in the atmosphere is preferably 10% or less, more preferably 5% or less, still more preferably 3% or less, and particularly preferably 1% or less.

[0113] Vacuum ultraviolet rays are ultraviolet rays with a wavelength of 200 nm or less. Among them, excimer light with a half-value width of 50 nm or less is most suitable. Examples of excimer light include argon (126 nm), krypton (146 nm), xenon (172 nm), and argon fluoride (193 nm). Among these, considering the ease of handling, the ability to form an effective uneven structure on the cured film, the curability of the curable composition, etc., xenon excimer light is suitable.

[0114] The integrated light amount of the vacuum ultraviolet rays to be irradiated is preferably 1 to 5000 mJ / cm 2 , more preferably 2 to 3000 mJ / cm 2 , still more preferably 3 to 1000 mJ / cm 2 , particularly preferably 5 to 500 mJ / cm 2 range. Also, the illuminance is preferably 1 to 1000 mW / cm 2 , more preferably 5 to 500 mW / cm 2 , still more preferably 10 to 300 mW / cm 2 range.

[0115] After irradiating with vacuum ultraviolet rays, for example, active energy rays other than vacuum ultraviolet rays such as ultraviolet rays can be further irradiated. Examples of the ultraviolet ray generation source include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, metal halide lamps, electrodeless UV lamps using magnetrons, LEDs, etc.

[0116] When using ultraviolet light, preferred curing conditions include, for example, using a high-pressure mercury lamp with an integrated ultraviolet light intensity of 340-380 nm, preferably 1-5000 mJ / cm². 2 More preferably 50-3000 mJ / cm² 2 More preferably 100-2000 mJ / cm² 2 Particularly preferred is 200 to 1000 mJ / cm². 2 The range is as follows. Furthermore, the illuminance is preferably 1 to 1000 mW / cm². 2 More preferably 50-500 mW / cm² 2 More preferably 80-300 mW / cm² 2 It is within the range.

[0117] (Primer layer) The primer layer is provided to impart various functions, such as improved adhesion, between the substrate and the cured film. The primer layer may have multiple functions in a single layer, or it may be composed of multiple layers.

[0118] In a preferred embodiment, the primer layer is an adhesion-enhancing layer. If the adhesion between the substrate layer and the cured film is insufficient, the laminate may not be usable depending on the application. By having an adhesion-enhancing layer, the adhesion between the substrate layer and the cured film is improved, and the laminate can be used for various applications. From the viewpoint of improving adhesion, it is preferable that the adhesion-enhancing layer contains either or both a resin and a crosslinking agent-derived compound.

[0119] Conventional known resins can be used as the resin included in the primer layer. Specific examples of resins include polyester resins, acrylic resins, urethane resins, and polyvinyl resins (polyvinyl alcohol, vinyl chloride-vinyl acetate copolymer, etc.). Among these, polyester resins, acrylic resins, and urethane resins are preferred considering adhesion performance and coating properties. When the substrate is a resin film, from the viewpoint of affinity with the substrate, the resin contained in the primer layer is preferably the same type of resin as the resin film. For example, when the substrate is a polyester film, the primer layer preferably contains polyester resin. When the substrate layer is a poly(meth)acrylate film, the primer layer preferably contains acrylic resin.

[0120] Polyester resins include those whose main components consist of polycarboxylic acids and polyhydroxy compounds. Examples of polycarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfisoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutaric acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, monopotassium salt of trimellitic acid, and their ester-forming derivatives. Examples of polyvalent hydroxy compounds include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, and the like. From these compounds, one or more can be appropriately selected, and a polyester resin can be synthesized by a conventional polycondensation reaction.

[0121] Acrylic resin is a polymer of polymerizable monomers, including (meth)acrylic monomers. Examples of acrylic resins include homopolymers and copolymers of (meth)acrylic monomers, and copolymers of (meth)acrylic monomers and polymerizable monomers other than (meth)acrylic monomers. Acrylic resins may be copolymers of these polymers with other polymers (e.g., polyester, polyurethane, etc.). Such copolymers are, for example, block copolymers and graft copolymers. Alternatively, polymers (and possibly mixtures of polymers) obtained by polymerizing polymerizable monomers in a solution or dispersion of polyester are also included. Similarly, polymers (and possibly mixtures of polymers) obtained by polymerizing polymerizable monomers in a solution or dispersion of polyurethane are also included. Similarly, polymers (and possibly mixtures of polymers) obtained by polymerizing polymerizable monomers in a solution or dispersion of other polymers are also included.

[0122] The polymerizable monomers mentioned above are not particularly limited, but some representative compounds include, for example, carboxyl group-containing monomers and their salts such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, monobutyl hydroxyl fumarate, and monobutyl hydroxyitaconate; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethyl Examples include alkyl(meth)acrylates such as hexyl(meth)acrylate and lauryl(meth)acrylate; nitrogen-containing monomers such as (meth)acrylamide, diacetone acrylamide, N-methylolacrylamide, and (meth)acrylonitrile; styrene compounds such as styrene, α-methylstyrene, divinylbenzene, and vinyltoluene; vinyl esters such as vinyl propionate and vinyl acetate; silicon-containing monomers such as γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane; phosphorus-containing vinyl monomers; vinyl halides such as vinyl chloride and pyridene chloride; and conjugated dienes such as butadiene.

[0123] Urethane resin is a polymer compound that contains urethane bonds within its molecule, and is typically synthesized by the reaction of a polyol with a polyisocyanate compound. Chain extenders may be used when synthesizing urethane resin. Examples of polyols used to obtain urethane resin include polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, and acrylic polyols. These compounds may be used individually or in combination of two or more.

[0124] Polycarbonate polyols are obtained by the reaction (de-alcoholization reaction) of a polyhydric alcohol with a carbonate compound. Examples of polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 3,3-dimethylolheptane. Examples of carbonate compounds include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate. Specific examples of polycarbonate polyols include poly(1,6-hexylene) carbonate and poly(3-methyl-1,5-pentylene) carbonate.

[0125] Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol.

[0126] Examples of polyester polyols include those obtained by the reaction of a polycarboxylic acid or its acid anhydride with a polyhydric alcohol, and those having derivative units of lactone compounds such as polycaprolactone. Examples of polycarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, and isophthalic acid. Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 1 Examples include ,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexanediol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyldialkanolamines, lactonediols, etc.

[0127] Considering adhesion performance, polyester polyols and polycarbonate polyols are preferred as polyols, with polyester polyols being particularly preferred.

[0128] Examples of polyisocyanate compounds used to obtain urethane resins include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylenediphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate; aliphatic diisocyanates having aromatic rings such as α,α,α',α'-tetramethylxylylene diisocyanate; aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate; and alicyclic diisocyanates such as cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and isopropylidene dicyclohexyl diisocyanate. These may be used individually or in combination of two or more.

[0129] There are no particular restrictions on the chain extender as long as it has two or more active groups that react with isocyanate groups, and generally, chain extenders having two hydroxyl groups or amino groups can be mainly used. Examples of chain extenders having two hydroxyl groups include glycol compounds such as aliphatic glycols like ethylene glycol, propylene glycol, and butanediol, aromatic glycols like xylylene glycol and bishydroxyethoxybenzene, and ester glycols like neopentyl glycol hydroxypivalate. Examples of chain extenders having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine, and diphenylmethanediamine; aliphatic diamines such as ethylenediamine, propylenediamine, hexanediamine, 2,2-dimethyl-1,3-propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine; and alicyclic diamines such as 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isopropylthincyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane, and 1,3-bisaminomethylcyclohexane.

[0130] Urethane resins are typically used in the form of dispersions or solutions. The medium for the dispersion or solution may be a solvent, but water is preferred. Aqueous dispersions or aqueous solutions of urethane resins include forced emulsification types using emulsifiers, self-emulsifying types with hydrophilic groups introduced into the structure of the urethane resin, and water-soluble types. In particular, self-emulsifying types, in which ionic groups are introduced into the structure of the urethane resin to form ionomers, are preferred because they offer excellent storage stability of the liquid and superior water resistance and transparency of the resulting primer layer.

[0131] Various ionic groups can be introduced into the structure of urethane resin, including carboxyl groups, sulfonic acid groups, phosphate groups, phosphonic acid groups, and quaternary ammonium bases, but carboxyl groups are preferred. The carboxyl groups are preferably in the form of salts neutralized with neutralizing agents such as ammonia, amines, alkali metals, and inorganic alkalis. Particularly preferred neutralizing agents are ammonia, trimethylamine, and triethylamine. In urethane resins having carboxyl groups neutralized with a neutralizing agent, the carboxyl groups from which the neutralizing agent has been removed during the drying process after coating can be used as crosslinking reaction sites by a crosslinking agent. This results in excellent stability in the liquid state before coating, and further improves the durability, solvent resistance, water resistance, and blocking resistance of the resulting primer layer.

[0132] Various methods can be used to introduce carboxyl groups into urethane resins at each stage of the polymerization reaction. For example, one method involves using a resin containing carboxyl groups as a copolymer component during prepolymer synthesis, or using a component containing carboxyl groups as one of the components of a polyol, polyisocyanate compound, or chain extender. In particular, a method using a carboxyl group-containing diol and introducing a desired amount of carboxyl groups by adjusting the amount of this component added is preferred. For example, a carboxyl group-containing diol can be copolymerized with a diol used in the synthesis of urethane resins. Examples of carboxyl group-containing diols include dimethylolpropionic acid, dimethylolbutanoic acid, bis-(2-hydroxyethyl)propionic acid, bis-(2-hydroxyethyl)butanoic acid, and salts of these in which the carboxyl groups have been neutralized with a neutralizing agent.

[0133] The primer layer preferably contains a compound derived from a crosslinking agent in order to strengthen the primer layer and improve performance such as adhesion. Known materials can be used as crosslinking agents, including, for example, melamine compounds, oxazoline compounds, isocyanate compounds, epoxy compounds, carbodiimide compounds, silane coupling compounds, hydrazide compounds, and aziridine compounds. Among these, melamine compounds, isocyanate compounds, epoxy compounds, oxazoline compounds, carbodiimide compounds, and silane coupling compounds are preferred, and from the viewpoint of further improving adhesion and durability, melamine compounds, oxazoline compounds, isocyanate compounds, and epoxy compounds are more preferred, with melamine compounds, oxazoline compounds, and isocyanate compounds being particularly preferred. These crosslinking agents may be used individually or in combination of two or more. Using two or more in combination may further improve adhesion and durability.

[0134] Melamine compounds are compounds that have a melamine skeleton within them. Examples include alkylolated melamine derivatives, compounds obtained by reacting alkylolated melamine derivatives with alcohol to partially or completely etherify them, and mixtures thereof. Examples of alcohols used for etherification include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, and isobutanol. Melamine compounds may be monomers, polymers of two or more units, or mixtures thereof. Furthermore, compounds in which urea or the like is co-condensed with a portion of the melamine can also be used, and catalysts can be used to increase the reactivity of the melamine compound. As for melamine compounds, those having a hydroxyl group are preferred, considering their reactivity with various other compounds.

[0135] Isocyanate compounds are compounds that have an isocyanate derivative structure, such as isocyanate compounds or blocked isocyanate compounds. Examples of isocyanate compounds include aromatic isocyanate compounds such as tolylene diisocyanate, xylylene diisocyanate, methylenediphenyl diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate; aliphatic isocyanate compounds having an aromatic ring such as α,α,α',α'-tetramethylxylylene diisocyanate; aliphatic isocyanate compounds such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate; and alicyclic isocyanate compounds such as cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylenebis(4-cyclohexyl isocyanate), and isopropylidene dicyclohexyl diisocyanate. Furthermore, polymers and derivatives of these isocyanate compounds, such as biuretized, isocyanurateized, uretdioneized, and carbodiimide-modified compounds, are also mentioned. These may be used individually or in combination of two or more. Among the above isocyanate compounds, aliphatic isocyanate compounds or alicyclic isocyanate compounds are more preferred than aromatic isocyanate compounds from the viewpoint of avoiding yellowing due to ultraviolet light.

[0136] Examples of blocked isocyanate compounds include those in which the isocyanate group of the above-mentioned isocyanate compounds is blocked by a blocking agent. Examples of blocking agents include phenolic compounds such as bisulfites, phenol, cresol, and ethylphenol; alcoholic compounds such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol, and ethanol; active methylene compounds such as dimethyl malonate, diethyl malonate, methyl isobutanoylacetate, methyl acetoacetate, ethyl acetoacetate, and acetylacetone; mercaptan compounds such as butyl mercaptan and dodecyl mercaptan; lactam compounds such as ε-caprolactam and δ-valerolactam; amine compounds such as diphenylaniline, aniline, and ethyleneimine; acid amide compounds such as acetanilide and acetic acid amide; and oxime compounds such as formaldehyde, acetaldehyde oxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime. These may be used individually or in combination of two or more. As for the blocked isocyanate compound, isocyanate compounds blocked by an active methylene compound are preferred from the viewpoint of being less likely to damage the primer layer.

[0137] Isocyanate compounds may be used individually or as mixtures or binders with various polymers. It is preferable to use mixtures or binders with polyester resins or urethane resins to improve the dispersibility and crosslinking properties of isocyanate compounds.

[0138] Oxazoline compounds are compounds that have an oxazoline group in their molecule. As the oxazoline compound, polymers containing an oxazoline group are preferred. Polymers containing an oxazoline group can be obtained by polymerization of an addition-polymerizable oxazoline group-containing monomer alone or with other monomers. Examples of addition-polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. These may be used individually or in combination of two or more. Among these, 2-isopropenyl-2-oxazoline is preferred because it is readily available industrially. Other monomers are not particularly limited as long as they are copolymerizable with addition-polymerizable oxazoline group-containing monomers, for example (meth)acrylates such as alkyl (meth)acrylates (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, and cyclohexyl groups); unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid and their salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; (meth)acrylates Examples include unsaturated amides such as lylamide, N-alkyl(meth)acrylamide, N,N-dialkyl(meth)acrylamide (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, and cyclohexyl groups); vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α,β-unsaturated monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride; and α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene. These may be used individually or in combination of two or more.

[0139] The amount of oxazoline groups per gram of oxazoline compound is preferably in the range of 0.5 to 10 mmol / g, more preferably 1 to 9 mmol / g, even more preferably 3 to 8 mmol / g, and particularly preferably 4 to 6 mmol / g. If the amount of oxazoline groups is within the above range, the durability of the coating film is improved and the adhesion can be easily adjusted.

[0140] Epoxy compounds are compounds that contain an epoxy group within their molecule. Examples of epoxy compounds include condensates of epichlorohydrin with compounds having a hydroxyl group or an amino group (such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, and bisphenol A), and include polyepoxy compounds, diepoxy compounds, monoepoxy compounds, and glycidylamine compounds. Examples of polyepoxy compounds include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris(2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, and trimethylolpropane polyglycidyl ether. Examples of diepoxy compounds include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcinol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and polytetramethylene glycol diglycidyl ether. Examples of monoepoxy compounds include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl ether. Examples of glycidylamine compounds include N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N-diglycidylamino)cyclohexane.

[0141] Carbodiimide compounds are compounds that have one or more carbodiimide structures or carbodiimide derivative structures within their molecule. As for carbodiimide compounds, polycarbodiimide compounds having two or more carbodiimide structures or carbodiimide derivative structures within the molecule are more preferred for better primer layer strength and other reasons.

[0142] Carbodiimide compounds can be synthesized using known techniques, and generally, condensation reactions of diisocyanate compounds are employed. The diisocyanate compounds are not particularly limited and can be either aromatic or aliphatic. Specifically, examples include tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, and dicyclohexylmethane diisocyanate.

[0143] To improve the water solubility and water dispersibility of polycarbodiimide compounds, surfactants may be added, or hydrophilic monomers such as polyalkylene oxides, quaternary ammonium salts of dialkylamino alcohols, and hydroxyalkyl sulfonates may be added, to the extent that the effects of the present invention are not lost.

[0144] Silane coupling compounds are organosilicon compounds that contain both an organic functional group and a hydrolyzable group such as an alkoxy group within a single molecule. Examples of silane coupling compounds include epoxy group-containing compounds such as 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; vinyl group-containing compounds such as vinyltrimethoxysilane and vinyltriethoxysilane; styryl group-containing compounds such as p-styryltrimethoxysilane and p-styryltriethoxysilane; (meth)acryloyl group-containing compounds such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane and 3-(meth)acryloxypropylmethyldiethoxysilane; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-2- Examples include amino group-containing compounds such as (aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyltriethoxysilane; isocyanurate group-containing compounds such as tris(trimethoxysilylpropyl)isocyanurate and tris(triethoxysilylpropyl)isocyanurate; and mercapto group-containing compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane.

[0145] Among the above compounds, epoxy group-containing silane coupling compounds, double bond-containing silane coupling compounds such as vinyl groups and (meth)acrylic groups, and amino group-containing silane coupling compounds are more preferred from the viewpoint of the strength of the primer layer.

[0146] The crosslinking agent reacts during the drying and film formation processes, improving the performance of the primer layer. It can be inferred that the formed primer layer contains compounds derived from the crosslinking agent, such as unreacted crosslinking agents, reacted compounds, or mixtures thereof.

[0147] The primer layer may contain particles for blocking or improving lubricity. The primer layer may, as necessary, contain additives such as defoaming agents, coating properties improvers, thickeners, organic lubricants, ultraviolet absorbers, antioxidants, foaming agents, dyes, and pigments, to the extent that it does not impair the spirit of the present invention.

[0148] The proportion of resin in 100% by mass of the primer layer is, for example, 5% by mass or more, preferably 10 to 99% by mass, more preferably 20 to 95% by mass, and even more preferably 30 to 90% by mass. When the proportion of resin is within the above range, the adhesion performance and appearance of the primer layer are better.

[0149] The proportion of crosslinking agent-derived compounds in 100% by mass of the primer layer is, for example, 80% by mass or less, preferably 0.5 to 65% by mass, more preferably 3 to 50% by mass, and even more preferably 5 to 40% by mass. When the proportion of crosslinking agent-derived compounds is within the above range, the adhesion performance and strength of the primer layer are better.

[0150] The thickness of the primer layer cannot be generalized as it depends on the material used for the primer layer and the performance to be achieved, but it is preferably in the range of 0.001 to 10 μm, more preferably 0.01 to 4 μm, and even more preferably 0.02 to 1 μm. The primer layer can be formed by known methods.

[0151] (Reverse side functional layer) The back-side functional layer is a layer provided on the side of the substrate opposite to the cured film side to impart various functions. Examples of back-side functional layers include adhesive layers, antistatic layers, refractive index adjusting layers, and antiblocking layers. A single back-side functional layer may have multiple functions, or it may be composed of multiple layers. The adhesive layer is provided to bond the laminate to various adherends. The antistatic layer is provided to prevent the adhesion of surrounding dust and other debris due to peeling charge or triboelectric charge, and the resulting defects, on the outermost surface of the laminate, particularly the outermost surface opposite to the uneven layer of the base material layer. The refractive index adjustment layer is provided, for example, to improve the total light transmittance of the laminate. The antiblocking layer is provided to reduce blocking of the laminate.

[0152] As the adhesive for forming the adhesive layer, known adhesives can be used, including acrylic, polyester, urethane, and rubber-based adhesives. Among these, acrylic adhesives are preferred considering their versatility. The antistatic layer and refractive index adjusting layer are the same as the antistatic layer and refractive index adjusting layer as surface functional layers, respectively.

[0153] The thickness of the functional backing layer cannot be generalized as it depends on the material used for the functional backing layer and the performance to be achieved, but for example, it is 0.001 to 30 μm. If the functional backing layer is an adhesive layer, it is preferably 0.01 to 30 μm, more preferably 0.1 to 20 μm. If the functional backing layer is an antistatic layer, it is preferably 0.001 to 10 μm, more preferably 0.01 to 5 μm. The functional back layer can be formed by known methods. Preferably, the functional back layer is formed by coating the substrate with a liquid prepared by adjusting the solid content concentration of the above-mentioned series of compounds as a solution or dispersion in a solvent to approximately 0.1 to 80% by mass. The functional back layer may also be formed after the cured film has been formed.

[0154] Conventional coating methods can be used to form the functional layer on the back surface, such as gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze coating, impregnation coating, kiss coating, spray coating, calender coating, and extrusion coating.

[0155] The drying and curing conditions for forming the functional layer on the back surface are not particularly limited, but in the case of a coating method, the drying temperature of the solvent such as water used in the coating liquid is usually in the range of 50 to 150°C, preferably 80 to 130°C, and more preferably 90 to 120°C. The drying time is approximately in the range of 3 to 200 seconds, preferably 5 to 120 seconds. Furthermore, in order to improve the strength of the functional layer on the back surface, if it is carried out in the film manufacturing process, a heat treatment process is usually performed in the range of 150 to 270°C, preferably 170 to 230°C, and more preferably 180 to 210°C. The time for this heat treatment process is approximately in the range of 3 to 200 seconds, preferably 5 to 120 seconds.

[0156] (Surface functional layer) Examples of surface functional layers include anti-fouling layers, antistatic layers, refractive index adjusting layers (anti-reflective layers, low-reflection layers, etc.), infrared absorption layers, ultraviolet absorption layers, and color correction layers. A single surface functional layer may have multiple functions, or it may be composed of multiple layers.

[0157] The antifouling layer is provided to improve the antifouling performance of the cured film by imparting water-repellent and oil-repellent properties. Conventional known materials such as silicone compounds, fluorine compounds, and long-chain alkyl group-containing compounds can be used for the antifouling layer. Among these, silicone compounds and fluorine compounds are preferred for exhibiting stronger antifouling performance, and fluorine compounds and long-chain alkyl group-containing compounds are preferred from the viewpoint of not contaminating the surface the antifouling layer comes into contact with.

[0158] Silicone compounds are compounds that have a silicone structure within their molecule. Examples include alkyl silicones such as dimethyl silicone and diethyl silicone, as well as phenyl silicones and methylphenyl silicones that have a phenyl group. Silicones with various functional groups can also be used, such as ether groups, hydroxyl groups, amino groups, epoxy groups, carboxylic acid groups, halogen groups such as fluorine, perfluoroalkyl groups, various alkyl groups, and various aromatic groups. Other common functional groups include silicones with vinyl groups and hydrogen silicones in which hydrogen atoms are directly bonded to silicon atoms. It is also possible to use both in combination as addition-type silicones (types resulting from the addition reaction of vinyl groups and hydrogensilane). Furthermore, a method of introducing a double bond such as an acryloyl group and reacting at the double bond site is also preferred.

[0159] Furthermore, modified silicones such as acrylic grafted silicone, silicone grafted acrylic, amino-modified silicone, and perfluoroalkyl-modified silicone can also be used as silicone compounds. Considering heat resistance and stain resistance, it is preferable to use a curable silicone resin, and any type of curing reaction, such as condensation type, addition type, or active energy ray curing type, can be used.

[0160] Fluorine compounds are compounds that contain a fluorine atom. Organic fluorine compounds are preferably used as fluorine compounds, and examples include perfluoroalkyl group compounds, polymers of olefin compounds containing a fluorine atom, and aromatic fluorine compounds such as fluorobenzene. From the viewpoint of release properties, compounds containing a perfluoroalkyl group are preferred. Furthermore, fluorine compounds containing long-chain alkyl compounds, as described later, can also be used.

[0161] Compounds containing perfluoroalkyl groups include, for example, perfluoroalkyl group-containing (meth)acrylates and their polymers, such as perfluoroalkyl (meth)acrylate, perfluoroalkyl methyl (meth)acrylate, 2-perfluoroalkyl ethyl (meth)acrylate, 3-perfluoroalkyl propyl (meth)acrylate, 3-perfluoroalkyl-1-methylpropyl (meth)acrylate, and 3-perfluoroalkyl-2-propenyl (meth)acrylate; and perfluoroalkyl group-containing vinyl ethers and their polymers, such as perfluoroalkyl methyl vinyl ether, 2-perfluoroalkyl ethyl vinyl ether, 3-perfluoropropyl vinyl ether, 3-perfluoroalkyl-1-methylpropyl vinyl ether, and 3-perfluoroalkyl-2-propenyl vinyl ether. Polymers are preferable considering heat resistance and stain resistance. Polymers may consist of a single compound or multiple compounds. Furthermore, from the viewpoint of stain resistance, the perfluoroalkyl group preferably has 3 to 11 carbon atoms. Polymers with compounds containing long-chain alkyl compounds, as described later, are also acceptable.

[0162] Long-chain alkyl group-containing compounds are compounds having a linear or branched alkyl group with typically 6 or more carbon atoms, preferably 8 or more, and more preferably 12 or more. Examples of alkyl groups include hexyl, octyl, decyl, lauryl, octadecyl, and behenyl groups. Examples of compounds containing alkyl groups include various long-chain alkyl group-containing polymer compounds, long-chain alkyl group-containing amine compounds, long-chain alkyl group-containing ether compounds, and long-chain alkyl group-containing quaternary ammonium salts. Polymer compounds are preferable when considering heat resistance and stain resistance. Furthermore, polymer compounds having long-chain alkyl groups as side chains are more preferable from the viewpoint of effectively obtaining antifouling properties.

[0163] Polymer compounds having long-chain alkyl groups as side chains can be obtained by reacting a polymer having a reactive group with a compound having an alkyl group that can react with the reactive group. Examples of the reactive group include hydroxyl groups, amino groups, carboxyl groups, and acid anhydrides. Examples of compounds having these reactive groups include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, reactive group-containing polyester resin, and reactive group-containing poly(meth)acrylic resin. Among these, polyvinyl alcohol is preferred considering its stain resistance and ease of handling.

[0164] Compounds having alkyl groups that can react with the above-mentioned reactive groups include, for example, long-chain alkyl group-containing isocyanates such as hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, and behenyl isocyanate; long-chain alkyl group-containing acid chlorides such as hexyl chloride, octyl chloride, decyl chloride, lauryl chloride, octadecyl chloride, and behenyl chloride; long-chain alkyl group-containing amines; and long-chain alkyl group-containing alcohols. Among these, long-chain alkyl group-containing isocyanates are preferred considering their release properties and ease of handling, and octadecyl isocyanate is particularly preferred.

[0165] Furthermore, polymer compounds having long-chain alkyl groups as side chains can also be obtained by polymerization of long-chain alkyl (meth)acrylates or by copolymerization of long-chain alkyl (meth)acrylates with other vinyl group-containing monomers. Examples of long-chain alkyl (meth)acrylates include hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, octadecyl (meth)acrylate, and behenyl (meth)acrylate.

[0166] The amount of antifouling material in the surface functional layer that exhibits the above-mentioned antifouling performance cannot be stated definitively as it depends on the material used, but in the case of silicone compounds and fluorine compounds, it is usually in the range of 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, and the upper limit may be 100% by mass. Furthermore, when using long-chain alkyl group-containing compounds, it is usually in the range of 0.1% by mass or more, preferably 1% by mass or more, and even more preferably 3% by mass or more, and the upper limit may be 100% by mass. Effective antifouling performance can be achieved by using within the above ranges.

[0167] When forming an antistatic layer as a surface functional layer, various conventionally known antistatic agents can be used. Alternatively, a method is also preferred in which a double bond, such as an acryloyl group, is introduced into a compound having an ammonium group, and the reaction occurs at the double bond.

[0168] Examples of refractive index adjustment layers include high refractive index layers, low refractive index layers, and laminates thereof. When forming a refractive index adjustment layer as a surface functional layer, materials used for the purpose of increasing the refractive index include, for example, aromatic compounds such as benzene structures, bisphenol A structures, melamine structures, and fluorene structures; condensed polycyclic aromatic compounds such as naphthalene, anthracene, phenanthrene, naphthalene, benzo[a]anthracene, benzo[a]phenanthrene, pyrene, benzo[c]phenanthrene, and perylene structures, which are considered to be high refractive index compounds among aromatics; metal oxides such as zirconium oxide, titanium oxide, zinc oxide, tin oxide, antimony oxide, yttrium oxide, indium oxide, cerium oxide, ATO (antimony-tin oxide), ITO (indium-tin oxide); metal chelate compounds such as titanium chelate and zirconium chelate; compounds containing sulfur elements; and compounds containing halogen elements.

[0169] Because metal oxides may have reduced adhesion depending on the application, it is preferable to use them in granular form. Furthermore, from the viewpoint of the appearance of the coating, the average particle size is preferably in the range of 100 nm or less, more preferably 50 nm or less, and even more preferably 25 nm or less.

[0170] When forming a refractive index adjustment layer as a surface functional layer, conventionally known materials can be used if the goal is to lower the refractive index. For example, acrylic resins and urethane resins are generally suitable because they have low refractive indices. In particular, compounds in which fluorine atoms are incorporated into the resin, such as fluororesins, compounds containing fluororesin in the main skeleton, and compounds containing perfluoroalkyl groups in the side chains, are also suitable. Inorganic materials include, for example, hollow silica particles, fluorine-containing inorganic compounds such as magnesium fluoride and calcium fluoride, and their hollow or nanoporous particles.

[0171] The thickness of the surface functional layer is preferably five times or less the height from the recess to the protrusion of the uneven structure of the cured film. This is because if the thickness exceeds five times the height of the unevenness, the matte finish due to the unevenness will be reduced. The thickness of the surface functional layer cannot be generalized as it depends on the height of the unevenness, but it is usually in the range of 0.001 to 3 μm, preferably 0.005 to 2 μm, more preferably 0.01 to 1 μm, even more preferably 0.02 to 0.5 μm, and particularly preferably 0.03 to 0.2 μm. By using the above range, it is possible to achieve both the expression of functionality by the surface functional layer and the matte finish due to the unevenness of the uneven layer. The surface functional layer can be formed by known methods.

[0172] The surface functional layer is preferably formed by coating the cured film with a liquid prepared by adjusting the solid content concentration of the above-mentioned series of compounds as a solution or dispersion in a solvent to approximately 0.1 to 80% by mass.

[0173] Conventional coating methods can be used to form the surface functional layer, such as gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze coating, impregnation coating, kiss coating, spray coating, calender coating, and extrusion coating.

[0174] The drying and curing conditions for forming the surface functional layer are not particularly limited, but in the case of a coating method, the drying temperature of the solvent such as water used in the coating liquid is usually in the range of 50 to 150°C, preferably 80 to 130°C, and more preferably 90 to 120°C. The drying time is approximately in the range of 3 to 200 seconds, preferably 5 to 120 seconds. Furthermore, in order to improve the strength of the surface functional layer, if it is carried out in the film manufacturing process, a heat treatment process is usually performed in the range of 150 to 270°C, preferably 170 to 230°C, and more preferably 180 to 210°C. The time for this heat treatment process is approximately in the range of 3 to 200 seconds, preferably 5 to 120 seconds.

[0175] (performance) As described above, the light-diffusing film forms an uneven surface with a haze of 50% or more, completely eliminating the shape of the light source and converting a linear light source into a surface light source. Therefore, while maintaining the basic optical properties of excellent light diffusion and focusing, and providing high total light transmittance and brightness, the number of components in the backlight unit can be reduced. Furthermore, the scratch resistance, which is a weakness of matte laminated films, is also good because the total ratio of monofunctional (meth)acrylate and difunctional (meth)acrylate is 70% by mass or less. In this invention, it has been found that good light diffusion and scratch resistance can be achieved because the haze is 50% or more and the Sz and Sv of the irregular wrinkle-like uneven surface structure are within a predetermined range.

[0176] [Application] Light-diffusing films can be suitably applied to liquid crystal display devices and their backlight units. In one example, the backlight unit is provided in a liquid crystal display device. The backlight unit is for illuminating the liquid crystal display elements. The backlight unit comprises a light source that generates light and a light-diffusing film placed between the light source and the liquid crystal display elements. In one example, the liquid crystal display device comprises liquid crystal display elements and a backlight unit for illuminating the liquid crystal display elements. [Examples]

[0177] The embodiments will be described in more detail below with reference to examples, but the present invention is not limited to the following description.

[0178] The materials used in the examples and comparative examples are as follows: • PET film (thickness: 50μm) • (Meth)acrylate (A): Dicyclopentenyloxyethyl acrylate (monofunctional acrylate) • (Meth)acrylate (B): 1,6-Hexanediol diacrylate (bifunctional acrylate) • (Meth)acrylate (C): A mixture of pentaerythritol triacrylate and pentaerythritol hexaacrylate (trifunctional acrylate, tetrafunctional acrylate) • (Meth)acrylate (D): Dipentaerythritol hexaacrylate (6-functional acrylate) • Urethane (meth)acrylate (E): Urethane acrylate (Mitsubishi Chemical Corporation, Shiko UV-3700B) (bifunctional urethane acrylate) • Urethane (meth)acrylate (F): Urethane acrylate (manufactured by Nemoto Kogyo Co., Ltd., Art Resin UN-904) (10-functional urethane acrylate) • Urethane (meth)acrylate (G): Urethane acrylate (Mitsubishi Chemical Corporation, Shiko UT-5670) (Acrylate with 7 or more functionalities) • (Meth)acrylic acrylate (H): Acrylate with 7 or more functional properties • Particles (I): Aluminum oxide particle dispersion (ALMIBK30WT%-H06, manufactured by CIK Nanotech) • Particles (J): Cross-linked acrylic particles with an average particle size of 1.8 μm (MX-180TA, manufactured by Soken Chemical Co., Ltd.) and aluminum oxide particle dispersion (ALMIBK30WT%-H06, manufactured by CIK Nanotech Co., Ltd.) • Photopolymerization initiator (K): Omnirad 184, manufactured by IGM Resins BV.

[0179] (Meth)acrylate (H): A specific acrylate with seven or more functionalities, i.e., (meth)acrylate(H), was prepared as follows: First, propylene glycol monomethyl ether (157 parts by mass), glycidyl methacrylate (98 parts by mass), methyl methacrylate (1.0 part by mass), ethyl acrylate (1.0 part by mass), mercaptopropyl trimethoxysilane (1.9 parts by mass), and 2,2'-azobis(2,4-dimethylvaleronitrile) (1.0 part by mass) were added to a flask equipped with a thermometer, a stirrer, and a reflux condenser, and the mixture was reacted at 65°C for 3 hours. Subsequently, 2,2'-azobis(2,4-dimethylvaleronitrile) (0.5 parts by mass) was added and the mixture was reacted for 3 hours. Then, propylene glycol monomethyl ether (138 parts by mass) and p-methoxyphenol (0.45 parts by mass) were added and the mixture was heated to 100°C. Next, acrylic acid (51 parts by mass) and triphenylphosphine (3.1 parts by mass) were added and the mixture was reacted at 110°C for 6 hours to obtain (meth)acrylic acrylate (H) having a radically polymerizable double bond in the side chain with an unsaturated double bond content (acryloyl equivalent (amount of introduced acryloyl group)) of 4.6 mmol / g. The weight-average molecular weight (Mw) of (meth)acrylic acrylate (H) was 17,700.

[0180] [Example 1] 20 parts by mass of (meth)acrylate (B), 20 parts by mass of (meth)acrylate (D), 60 parts by mass of urethane (meth)acrylate (G), 10 parts by mass of particles (J), and 5 parts by mass of photopolymerization initiator (L) were mixed, methyl ethyl ketone (MEK) was added to a solid content concentration of 40% by mass, and the mixture was stirred until homogeneous. The resulting coating solution was applied onto the primer layer of a polyester film substrate and dried at 70°C for 1 minute. Then, excimer light (half-width 14 nm) from xenon (wavelength 172 nm) was irradiated at a dose of 10 mJ / cm². 2 , illuminance 11mW / cm 2 The dried coating was irradiated using a Ushio Inc. xenon excimer 172nm light irradiation unit SVS3, lamp unit model: UEM343W-172ST (lamp house model: H2112, ignition power supply model: B0314), nitrogen flow (oxygen concentration 0.01% or less). Furthermore, the coating was irradiated with a high-pressure mercury lamp in an air atmosphere with an integrated luminous intensity of 300 mJ / cm². 2 , illuminance 150mW / cm 2 A light-diffusing film having a cured film with a 5 μm thick (after curing) uneven structure was obtained on a substrate by irradiating it with ultraviolet light using a UV conveyor (of an iGraphics high-power UV device (model: US5-X1802-X1202)).

[0181] [Examples 2-10, Comparative Examples 1-9] A light-diffusing film was obtained under the same conditions as in Example 1, except that the composition of the curable composition was changed as shown in Table 1.

[0182] [Table 1]

[0183] [Measurement method] (Weight average molecular weight: Mw) The weight-average molecular weight (Mw) was measured using gel permeation chromatography (GPC) with the "HLC-8120" (Tosoh Corporation). The TSKgel G5000HXL*GMHXL-L column (Tosoh Corporation) was used. Calibration curves were created using standard polystyrenes F288 / F80 / F40 / F10 / F4 / F1 / A5000 / A1000 / A500 (Tosoh Corporation) and styrene. Measurements were performed using a 100 μl solution of the polymer dissolved in tetrahydrofuran at a concentration of 0.4%, at a column oven temperature of 40°C. The weight-average molecular weight (Mw) was calculated on a standard polystyrene basis.

[0184] (Total light transmittance, haze) The target of measurement was a light-diffusing film formed by curing a film on a transparent substrate. Total light transmittance and haze were measured using a haze meter "SH7000" manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS Z8722Z (Geometric conditions for irradiation and reception of light-transmitting objects), JIS K7361-1 (Plastics - Test method for total light transmittance of transparent materials), and JIS K7136 (Plastics - Method for determining haze of transparent materials).

[0185] (20° gloss, 60° gloss) The measurement target was a light-diffusing film with a cured film formed on a transparent substrate. 20° gloss and 60° gloss (20° specular gloss and 60° specular gloss) were measured in accordance with JIS Z 8741 using a gloss meter "VG2000" manufactured by Nippon Denshoku Industries Co., Ltd. A lower gloss value indicates superior matte finish.

[0186] (Ra, Rsm, θα, Sz, Sv, S5p, Vvv, Sdq, Sdr) Using a surface topography system (Hitachi High-Tech Science Corporation's "Scanning White Air Interferometry Microscope VS1330"), the surface topography of a 703.12 μm × 937.42 μm area on the surface of the hardened film was measured using optical interferometry. The data was then read after interpolation and baseline correction. The objective lens magnification during measurement was set to 20x.

[0187] (Scratch resistance test) In accordance with JIS K7136:2000, the haze and gloss of the cured film of each example of light-diffusing film were compared after applying a load of 1 kgf to the steel wool with #0000 grade steel wool and rubbing the surface of the cured film 100 times back and forth, with the haze and gloss before rubbing. The amount of change (absolute value) for each was judged according to the following criteria. ·Total light transmittance A: Less than 2.0%, B: 2.0% or more but less than 5.0%, C: 5.0% or more. · Hayes A: Less than 2.0%, B: 2.0% or more but less than 5.0%, C: 5.0% or more. 20° Gloss A: Less than 1.0%, B: 1.0% or more but less than 3.0%, C: 3.0% or more. 60° Gloss A: Less than 2.0%, B: 2.0% or more but less than 5.0%, C: 5.0% or more.

[0188] The results are shown in Table 2.

[0189] [Table 2]

[0190] In Examples 1-10, the cured film had a Sz of 4 μm or more and an Sv of 2.5 μm or more. At this time, a matte finish with a haze of 50% or more and a 60° gloss of 20% or less was achieved. Furthermore, by limiting the total amount of monofunctional (meth)acrylate and bifunctional (meth)acrylate to 70% or less, excellent scratch resistance was achieved, meeting the test conditions for scratch resistance, resulting in favorable results. In contrast, Comparative Examples 1-6 did not satisfy the conditions of having an Sz of 4 μm or more and an Sv of 2.5 μm or more. At this time, the haze was 50% or less, and the target haze was not achieved.

[0191] In Comparative Examples 7-9, Sz was 4 μm or higher, and Sv was 2.5 μm or higher. Haze was 50% or higher, and a matte finish with a 60° gloss of 20% or less was achieved. However, the total proportion of monofunctional (meth)acrylate and bifunctional (meth)acrylate was 70% or higher. As a result, the degree of three-dimensional crosslinking decreased, and scratch resistance that met the test conditions for scratch resistance could not be obtained.

[0192] Although the present invention has been described above with reference to specific embodiments, each embodiment is presented as an example and does not limit the scope of the present invention. Each embodiment described herein can be modified in various ways within the scope in which the effects of the invention are achieved, and can be combined with features described in other embodiments to the extent that is feasible. [Industrial applicability]

[0193] The light-diffusing film of the present invention can completely eliminate the shape of the light source and convert a linear light source into a surface light source. Therefore, while maintaining the basic optical properties of excellent light diffusion and focusing, and providing high total light transmittance and brightness, the number of components in the backlight unit can be reduced. Thus, backlight units and liquid crystal displays equipped with such a light-diffusing film can reduce the cost of various products using liquid crystal displays. Furthermore, the reduction in components reduces the loss of light rays passing between components. Therefore, the number of light sources can be reduced or the power of the light sources can be reduced. Moreover, the reduction in components prevents light interference between sheets. Therefore, the image quality of the displayed image is improved. In addition, the light-diffusing layer has excellent scratch resistance. Thus, the light-diffusing film of the present invention is easy to handle during manufacturing, storage, transportation, and use, and yield is improved. [Explanation of Symbols]

[0194] 1. Light-diffusing film 2 Transparent base material 3 Cured film

Claims

1. The transparent substrate and the cured film of a curable composition provided on the surface of the transparent substrate are provided. The cured film has an irregular, wrinkled, uneven surface structure. The curable composition contains at least a monofunctional (meth)acrylate, a difunctional (meth)acrylate, and a polyfunctional (meth)acrylate with three or more functions. The total proportion of the monofunctional (meth)acrylate and the bifunctional (meth)acrylate is 50% by mass or less with respect to the total mass of the nonvolatile content of the curable composition. The maximum distance Sz from the highest point to the lowest point of the uneven surface of the aforementioned irregular wrinkle-like uneven structure, as defined in ISO 25178, is 4 μm or more. The absolute value Sv of the minimum height from the average plane of the uneven surface defined in ISO 25178 for the aforementioned irregular wrinkle-like uneven structure is 2.5 μm or more. A light-diffusing film with a haze of 50% or more.

2. The light-diffusing film according to claim 1, wherein the irregular wrinkled uneven structure is formed by curing the surface side of a coating film of a curable composition by irradiation with excimer light to form a cured film, and then curing the interior of the coating film by irradiation with active energy rays other than vacuum ultraviolet light, causing the cured film on the surface side to buckle.

3. The light-diffusing film according to claim 1, wherein the curable composition may further contain particles, and the proportion of the particles is 0 to 30% by mass with respect to the total mass of the non-volatile components of the curable composition.

4. The light-diffusing film according to claim 3, wherein the average particle size of the particles is 0.01 to 30 μm.

5. The light-diffusing film according to claim 1, wherein the 60° gloss of the surface of the cured film is 25 or less.

6. The light-diffusing film according to claim 1, wherein the average value S5p of the heights of the five highest peak regions of the uneven structure, as defined in ISO 25178, is 1.5 μm or more.

7. The void volume value Vvv in the valleys of the aforementioned uneven structure at a load area ratio p% as defined by ISO 25178 is 0.03 ml / m ２ The above describes the light-diffusing film according to claim 1.

8. The light-diffusing film according to claim 1, wherein the root mean square gradient Sdq of the coating surface having the irregular wrinkle-like uneven structure as defined in ISO 25178 is 0.1 or greater.

9. The light-diffusing film according to claim 1, wherein the unfolded interface area ratio Sdr of the coating surface defined in ISO 25178 for the irregular wrinkle-like uneven structure is 1% or more.

10. The light-diffusing film according to claim 1, wherein the transparent substrate is at least one selected from the group consisting of cycloolefin polymer film, polyethylene terephthalate film, polyacrylic polymer film, and triacetylcellulose film.

11. A backlight unit for illuminating liquid crystal display elements, provided in a liquid crystal display device, A light source that generates light, The system comprises a light-diffusing film disposed between the light source and the liquid crystal display element, A backlight unit in which the light-diffusing film is the light-diffusing film according to any one of claims 1 to 10.

12. LCD display buttons and A backlight unit for illuminating the liquid crystal display element, Equipped with, A liquid crystal display device wherein the backlight unit is the backlight unit described in claim 11.

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