Anti-reflective film

Abstract

An anti-reflective film is provided that has excellent scratch resistance, high anti-fouling properties, and wear resistance, and additionally has solvent resistance capable of withstanding friction from a cloth or finger soaked in a solvent such as alcohol. The anti-reflective film comprises a base film (12), a hard coating layer (14) formed on the surface of the base film (12), and a low refractive index layer (16) formed on the surface of the hard coating layer (14). The low refractive index layer (16) is composed of a cured product of an ionizing radiation curable composition containing a (meth)acrylate compound having reactive groups, hollow silica particles, and alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming a bond with the (meth)acrylate compound, and the anti-reflective film (10) has a surface water contact angle of 100° or more.

Description

Technology Field

[0001] The present invention relates to an anti-reflective film (anti-glare film), and more specifically, to an anti-reflective film suitable for use on the surface of a display such as a liquid crystal display, an organic EL display, or a touch panel of a smartphone. Background Technology

[0002] In order to prevent external light from reflecting off the screen, an anti-reflective film may be placed on the surface of a display such as a liquid crystal display, an organic EL display, or a touch panel for a smartphone. As for the anti-reflective film, it is known that a hard coating layer and an anti-reflective layer (low refractive index layer) are provided in this order on a substrate film. For example, in Patent Document 1 based on the application of the present applicant, the composition of the low refractive index layer formed on the surface of the hard coating layer is examined to improve the anti-reflective properties, scratch resistance, and anti-fouling properties of the anti-reflective film. In Patent Document 1, a fluorine-containing compound is contained in the low refractive index layer, which contributes to the improvement of anti-fouling properties. Prior art literature

[0003] International Patent Publication No. 2021 / 020504 The problem to be solved

[0004] For anti-reflective films, particularly those placed on the surface of touch panels and frequently subjected to contact by fingers, it is required to possess high antifouling properties. As disclosed in Patent Document 1, the antifouling properties of an anti-reflective film can be improved by adding a substance with antifouling action, such as a fluorine-containing compound, to a low-refractive-index layer constituting the anti-reflective film. On the other hand, a form is also used in which an antifouling layer containing such an antifouling action is placed on the surface of the low-refractive-index layer as a layer independent of the low-refractive-index layer. However, even if an antifouling layer is placed, if sufficiently high antifouling properties are not obtained, or if the surface is worn down by repeated contact with fingers, the antifouling properties may deteriorate. For anti-reflective films frequently subjected to contact by fingers, in addition to possessing high anti-reflective and antifouling properties, high scratch resistance and high wear resistance are important characteristics from the perspective of durability during use.

[0005] Furthermore, recently, there has been an increasing trend of wiping the surface of anti-reflective films—particularly those placed on the surface of touch panels and frequently touched by fingers—with solvents such as alcohol for cleaning or sterilization. However, conventional anti-reflective films have a problem in that wiping them with an alcohol-soaked cloth or frequently touching them with alcohol-soaked fingers causes the surface to wear out or reduces their antifouling properties.

[0006] The problem that the present invention aims to solve is to provide an anti-reflective film that possesses excellent scratch resistance, high antifouling properties and abrasion resistance, and additionally has solvent resistance capable of withstanding friction from a cloth or finger contaminated with a solvent such as alcohol. means of solving the problem

[0007] To solve the above problem, the anti-reflection film according to the present invention has the following configuration.

[0008] [1] The first anti-reflection film according to the present invention is an anti-reflection film comprising a base film, a hard coating layer formed on the surface of the base film, and a low refractive index layer formed on the surface of the hard coating layer,

[0009] The low refractive index layer is composed of a cured product of an ionizing radiation-curable composition containing a (meth)acrylate compound having reactive groups, hollow silica particles, and alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming a bond with the (meth)acrylate compound.

[0010] The surface water contact angle of the above anti-reflective film is 100° or more.

[0011] [2] In the above [1] sun, the ionizing radiation curable composition constituting the low refractive index layer may additionally contain fluorine-containing (meth)acrylate.

[0012] [3] The second anti-reflection film according to the present invention comprises a base film, a hard coating layer formed on the surface of the base film, a low refractive index layer formed on the surface of the hard coating layer, and an antifouling layer formed on the surface of the low refractive index layer, wherein

[0013] The low refractive index layer is composed of a cured product of an ionizing radiation-curable composition comprising a (meth)acrylate compound having reactive groups, hollow silica particles, and alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming a bond with the (meth)acrylate compound.

[0014] The above antifouling layer is composed of a cured product of an ionizing radiation-curable composition containing a fluorine-containing (meth)acrylate, and

[0015] The surface water contact angle of the above anti-reflective film is 100° or more.

[0016] [4] In the above [3] sun, the content of the fluorine-containing (meth)acrylate in the antifouling layer is 90 mass% or more based on the total solid content of the antifouling layer.

[0017] [5] In the above [3] or [4] sun, the low refractive index layer is preferably not to contain a fluorine-containing compound. Effects of the invention

[0018] The first anti-reflection film according to the present invention having the configuration of [1] above is an anti-reflection film having a base film, a hard coating layer formed on the surface of the base film, and a low refractive index layer formed on the surface of the hard coating layer, wherein the low refractive index layer is composed of a cured product of an ionizing radiation curable composition containing a (meth)acrylate compound having a reactive group, hollow silica particles, and alumina particles surface-treated with a silane coupling agent having a reactive group capable of forming a bond with the (meth)acrylate compound, and the surface water contact angle of the anti-reflection film is 100° or more. By the fact that the low refractive index layer is composed of a cured product of a composition containing alumina particles surface-treated with a silane coupling agent having a reactive group capable of forming a bond with the (meth)acrylate compound together with the (meth)acrylate compound, the anti-reflection film has excellent scratch resistance and high anti-fouling and wear resistance. In addition, by making the surface water contact angle of the anti-reflective film having such a composition 100° or more, the anti-reflective film has high antifouling properties and at the same time has solvent resistance capable of withstanding friction from a cloth or finger that has (attached) a solvent such as alcohol.

[0019] In the above [2], the ionizing radiation curable composition constituting the low refractive index layer can effectively improve the surface antifouling and solvent resistance of the anti-reflective film by additionally containing fluorine-containing (meth)acrylate.

[0020] The second anti-reflection film according to the present invention having the configuration of [3] above is an anti-reflection film comprising a base film, a hard coating layer formed on the surface of the base film, a low refractive index layer formed on the surface of the hard coating layer, and an antifouling layer formed on the surface of the low refractive index layer, wherein the low refractive index layer is composed of a cured product of an ionizing radiation curable composition comprising a (meth)acrylate compound having reactive groups, hollow silica particles, and alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming a bond with the (meth)acrylate compound, and the antifouling layer is composed of a cured product of an ionizing radiation curable composition comprising a fluorine-containing (meth)acrylate, and the surface water contact angle of the anti-reflection film is 100° or more. The low refractive index layer is composed of a cured product of a composition containing alumina particles surface-treated with a silane coupling agent having a reactive group capable of forming a bond with the (meth)acrylate compound in addition to the (meth)acrylate compound, and furthermore, the surface of the low refractive index layer is provided with an antifouling layer composed of a cured product of a composition containing a fluorine-containing (meth)acrylate, thereby the antireflective film has excellent scratch resistance and, at the same time, high antifouling and wear durability. Moreover, by making the surface water contact angle of the antireflective film 100° or more, the antireflective film has high antifouling properties and, at the same time, possesses solvent resistance capable of withstanding friction from a cloth or finger soaked in a solvent such as alcohol.

[0021] In the above [4] example, the antifouling properties of the anti-reflective film can be effectively improved by making the content of the fluorine-containing (meth)acrylate in the antifouling layer 90 mass% or more based on the total solid content of the antifouling layer.

[0022] In the above [5] sun, the low refractive index layer does not contain a fluorine-containing compound, thereby effectively improving the scratch resistance of the anti-reflective film. Brief explanation of the drawing

[0023] FIG. 1 is a cross-sectional view of an anti-reflective film according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of an anti-reflective film according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view of an anti-reflective film according to a third embodiment of the present invention. FIG. 4 is a cross-sectional view of an anti-reflective film according to a fourth embodiment of the present invention. FIG. 5 is a cross-sectional view of an anti-reflection film according to the fifth embodiment of the present invention. Specific details for implementing the invention

[0024] The present invention will be described in detail below. In this specification, various physical properties refer to values ​​at room temperature and in the atmosphere unless otherwise noted. In addition, in this specification, the refractive index of a material and a material layer refers to the refractive index at a measurement wavelength of 589.3 nm unless otherwise noted.

[0025] <Anti-reflective film of the first embodiment>

[0026] FIG. 1 is a cross-sectional view of an anti-reflection film according to a first embodiment of the present invention. As shown in FIG. 1, the anti-reflection film (10) according to the first embodiment of the present invention comprises a base film (12), a hard coating layer (14) formed on the surface of the base film (12), and a low refractive index layer (16) formed on the surface of the hard coating layer (14). In this embodiment, each of the above-described layers is laminated in sequence without interposing other layers between them. The low refractive index layer (16) is the outermost layer exposed as the entire anti-reflection film (10).

[0027] (Insulated film)

[0028] The substrate film (12) is not specifically limited as long as it has transparency. Examples of the substrate film (12) include transparent polymer films, glass films, etc. Transparency means that the total light (light) transmittance in the visible light wavelength range is 50% or more, and the total light transmittance is more preferably 85% or more. The above total light transmittance can be measured in accordance with JIS K7361-1 (1997). The thickness of the substrate film (12) is not specifically limited, but from the perspective of excellent handling, it is preferable that it be within the range of 2 μm or more and 500 μm or less. More preferably, it is within the range of 2 μm or more and 200 μm or less. In addition, the term "film" generally refers to a thickness of less than 0.25 mm, but even if the thickness is 0.25 mm or more, if it is possible to wind it into a roll form, it is included in the term "film" even if the thickness is 0.25 mm or more.

[0029] Polymer materials of the base film (12) may include polyester resins such as polyethylene terephthalate resin and polyethylene naphthalate resin, polycarbonate resin, poly(meth)acrylate resin, polystyrene resin, polyamide resin, polyimide resin, polyacrylonitrile resin, polypropylene resin, polyethylene resin, polycycloolefin resin, cycloolefin copolymer resin, polyolefin resin, cellulose-based resins such as triacetyl cellulose resin and diacetyl cellulose resin, polyphenylene sulfide resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, etc. The polymer material of the base film (12) may be composed of only one of these types, or may be composed of a combination of two or more types. Among these, polyethylene terephthalate resin, polyimide resin, polycarbonate resin, poly(meth)acrylate resin, polycycloolefin resin, cycloolefin copolymer resin, and triacetyl cellulose resin are more preferred in terms of optical properties or durability.

[0030] The substrate film (12) may be composed of a single layer containing one or more of the above polymer materials, or may be composed of two or more layers, such as a layer containing one or more of the above polymer materials and a layer containing one or more of the above polymer materials different from the layer.

[0031] (Hard coating layer)

[0032] The hard coating layer (14) contributes to improving the scratch resistance of the anti-reflective film (10). The hard coating layer (14) is composed of a cured product of an ionizing radiation curable composition containing a (meth)acrylate compound having a reactive group. Ionizing radiation refers to electromagnetic waves or charged particle beams that have energy quanta capable of polymerizing or crosslinking molecules. Examples of ionizing radiation include electromagnetic waves such as ultraviolet (UV), X-rays, and gamma rays, and charged particle beams such as electron beams (EB), α-rays, and ion beams. Among these, ultraviolet (UV) is particularly preferred from the perspective of productivity. Hereinafter, the ionizing radiation curable composition may simply be referred to as a curable composition. Furthermore, in this specification, "(meth)acrylate" means "at least one of acrylate and methacrylate." "(meth)acryloyl" means "at least one of acryloyl and methacryloyl." "(Meta)acrylate" means "at least one of acrylate and methacrylate." "(Meta)acrylate compound" is a compound having a (meth)acryloyl group, and examples include monomers, oligomers, prepolymers, etc. Hereinafter, (meth)acrylate compounds may be simply referred to as (meth)acrylates.

[0033] The (meth)acrylate may be a monofunctional (meth)acrylate or a polyfunctional (meth)acrylate. Alternatively, it may be composed of a combination of a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate. As for the curable composition, it is more preferable to include a polyfunctional (meth)acrylate as the (meth)acrylate to improve curability.

[0034] Examples of (meth)acrylates include urethane (meth)acrylates, silicon (meth)acrylates, alkyl (meth)acrylates, aryl (meth)acrylates, etc. Among these, urethane (meth)acrylates, particularly urethane (meth)acrylate oligomers, are preferred. Specific examples of urethane (meth)acrylates include those obtained by reacting a polyisocyanate compound with a hydroxyl-containing (meth)acrylate compound, and, if necessary, a polyol compound. Examples of polyisocyanate compounds include diisocyanate compounds such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and 4,4'-diphenylmethane diisocyanate, as well as their nurate modifieds, adduct modifieds, and biuret modifieds. Examples of hydroxyl group-containing (meth)acrylate compounds include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, trimethylolpropane diacrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and their polyoxyalkylene modifieds and polylactone modifieds. Examples of polyol compounds include ethylene glycol, propylene glycol, butanediol, hexanediol, polyoxyethylene glycol, polyoxypropylene glycol, glycerin, trimethylolpropane, pentaerythritol, biphenol, bisphenol, etc. When the curable composition for forming the hard coating layer (14) includes urethane (meth)acrylate as a UV-curable resin, the hard coating layer (14) has appropriate flexibility, so the bending resistance of the anti-reflective film (10) is increased, and it can be preferably used in flexible displays that undergo repeated bending, such as foldable displays or rollable displays. In addition, even if the base film (12) is formed of, for example, polycycloolefin or cycloolefin copolymer and is relatively brittle, it is easy to suppress cracking of the base film (12).

[0035] It is also preferable that a pentaerythritol (meth)acrylate compound be included as the (meth)acrylate constituting the curable composition. Specific examples of pentaerythritol (meth)acrylate compounds include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tetra(meth)acrylate, tripentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, and tripentaerythritol octa(meth)acrylate. In particular, it is preferable that pentaerythritol tri(meth)acrylate be included in the curable composition.

[0036] In the curable composition forming the hard coating layer (14), a non-ultraviolet curable resin may or may not be included in addition to the ultraviolet curable resin. Additionally, in the curable composition forming the hard coating layer (14), a photopolymerization initiator may be included. Furthermore, if necessary, additives that can generally be added to the curable composition may be included. Examples of additives include dispersants, leveling agents, defoaming agents, thixotropic agents, antifouling agents, antibacterial agents, flame retardants, slip agents, antistatic agents, inorganic particles, resin particles, etc. Additionally, if necessary, a solvent may be included.

[0037] Examples of non-UV curable resins include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyester resins, polyether resins, polyolefin resins, and polyamide resins. Examples of thermosetting resins include unsaturated polyester resins, epoxy resins, alkyd resins, and phenolic resins.

[0038] Examples of photopolymerization initiators include alkylphenone-based, acylphosphine oxide-based, and oxime ester-based photopolymerization initiators. As alkylphenone-based photopolymerization initiators, 2,2'-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzylmethyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, Examples include 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-(4-morpholinophenyl)-1-butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, N,N-dimethylaminoacetphenone, etc. Examples of acylphosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, etc. Examples of oxime ester-based photopolymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), and ethano-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyloxime). The photopolymerization initiator may be used as a single type or in combination of two or more types.

[0039] The content of the photopolymerization initiator is preferably in the range of 0.1 mass% or more and 10 mass% or less, based on the total amount of solids of the curable composition. More preferably, it is 1 mass% or more and 5 mass% or less.

[0040] Inorganic particles and resin particles may be added to the hard coating layer (14) for purposes such as preventing blocking of the hard coating layer (14) or adjusting the refractive index of the hard coating layer (14). By forming fine surface irregularities on the hard coating layer (14) through the added inorganic particles or resin particles, it is easy to suppress blocking where the surface and back surfaces adhere when the hard coating film, which consists of the base film (12) and the hard coating layer (14) before forming the low refractive index layer (16), is wound into a roll shape.

[0041] As inorganic particles capable of adjusting the refractive index of the hard coating layer (14), examples include metal oxide particles composed of oxides of metals such as titanium, zirconium, tin, zinc, silicon, niobium, aluminum, chromium, magnesium, germanium, gallium, antimony, and platinum. These may be used as optically adjustable inorganic particles, either as a single type or in combination of two or more types. Among these, titanium oxide and zirconium oxide are particularly preferred from the perspective of excellent compatibility of high refractive index and transparency. Additionally, as resin particles, examples include resin particles composed of resins such as (meth)acrylic resin, styrene resin, styrene-(meth)acrylic resin, urethane resin, polyamide resin, silicone resin, epoxy resin, phenolic resin, polyethylene resin, and cellulose. These may be used as resin particles, either as a single type or in combination of two or more types.

[0042] The thickness of the hard coating layer (14) is not particularly limited, but it is preferable that it be 0.5 μm or more from the perspective of having sufficient hardness. More preferably, it is 0.75 μm or more. In addition, it is preferable that it be 20 μm or less from the perspective of easily suppressing curl caused by the difference in thermal shrinkage with the substrate film (12). More preferably, it is 10 μm or less. The thickness of the hard coating layer (14) is the thickness of the relatively smooth portion in the thickness direction, in the portion without irregularities caused by inorganic particles or resin particles.

[0043] The refractive index of the hard coating layer (14) is preferably in the range of 1.49 or higher and 1.56 or lower in order to suppress interference stains caused by the difference in refractive index between the substrate film (12) and the hard coating layer (14).

[0044] The arithmetic mean roughness or roughness (Ra) of the surface on which surface irregularities are formed of the hard coating layer (14) is preferably within the range of 0.3 nm or more and 20 nm or less for the purpose of blocking inhibition, etc. More preferably, it is 0.5 nm or more and also 10 nm or less.

[0045] Examples of solvents used in the curable composition for forming the hard coating layer (14) include alcohol-based solvents such as ethanol, isopropyl alcohol (IPA), n-butyl alcohol (NBA), ethylene glycol monomethyl ether (EGM), ethylene glycol monoisopropyl ether (IPG), propylene glycol monomethyl ether (PGM), and diethylene glycol monobutyl ether; ketone-based solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, and acetone; aromatic-based solvents such as toluene and xylene; ester-based solvents such as ethyl acetate (EtAc), propyl acetate, isopropyl acetate, and butyl acetate (BuAc); and amide-based solvents such as N-methylpyrrolidone, acetamide, and dimethylformamide. These may be used as solvents in a single form or in combination of two or more forms.

[0046] The solid content concentration of the curable composition (concentration of components other than the solvent) should be appropriately determined by taking into account coating properties, film thickness, etc. For example, it is good to set it to 1 mass% or more and 90 mass% or less, or 1.5 mass% or more and 80 mass% or less, or 2 mass% or more and 70 mass% or less.

[0047] (low refractive index layer)

[0048] In the anti-reflection film (10) according to the present embodiment, a low refractive index layer (16) is provided as an anti-reflection layer on the surface of the hard coating layer (14). The low refractive index layer (16) has a lower refractive index than the hard coating layer (14), and exhibits an anti-reflection effect due to the difference in refractive index with the hard coating layer (14).

[0049] The low refractive index layer (16) is composed of a cured product of an ionizing radiation curable composition containing a (meth)acrylate compound having reactive groups as a binder resin, alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming bonds with the (meth)acrylate compound, and hollow silica particles. As described above regarding the hard coating layer (14), ionizing radiation includes various electromagnetic waves and charged particle beams, but the low refractive index layer (16) is preferably composed of a cured product of an ultraviolet (UV) curable composition. Furthermore, it is preferable that the reactive groups contained in the (meth)acrylate compound and the silane coupling agent are ultraviolet reactive. A suitable composition of the composition will be described below.

[0050] Examples of (meth)acrylate compounds having a reactive group include urethane (meth)acrylate, silicon (meth)acrylate, alkyl (meth)acrylate, aryl (meth)acrylate, etc. Additionally, the (meth)acrylate compound may have only a (meth)acryloyl group as the reactive group, or may have other reactive groups in addition to the (meth)acryloyl group.

[0051] The (meth)acrylate may consist solely of monofunctional (meth)acrylates, solely of polyfunctional (meth)acrylates, or a combination of monofunctional (meth)acrylates and polyfunctional (meth)acrylates. It is more preferable to include polyfunctional (meth)acrylates as the (meth)acrylates.

[0052] Monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (Meth)acrylate, Lauryl (Meth)acrylate, Stearyl (Meth)acrylate, Isostearyl (Meth)acrylate, Isobornyl (Meth)acrylate, 1-Adamantyl (Meth)acrylate, 2-Methyl-2-Adamantyl (Meth)acrylate, 2-Ethyl-2-Adamantyl (Meth)acrylate, Bornyl (Meth)acrylate, Tricyclodecanyl (Meth)acrylate, Dicyclofentanyl (Meth)acrylate, Dicyclopentenyl (Meth)acrylate, Cyclohexyl (Meth)acrylate, Benzyl (Meth)acrylate, 1-Naphthylmethyl (Meth)acrylate, 2-Naphthylmethyl (Meth)acrylate, Phenoxyethyl (Meth)acrylate, Phenoxy-2-methylethyl (meth)acrylate, phenoxyethoxyethyl (meth)acrylate, 3-phenoxy-2-hydroxypropyl (meth)acrylate, 2-phenylphenoxyethyl (meth)acrylate, 4-phenylphenoxyethyl (meth)acrylate, 3-(2-phenylphenyl)-2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, methoxyethylene glycol (Meta)acrylate,Examples include ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, etc.

[0053] Examples of polyfunctional (meth)acrylates include difunctional (meth)acrylates, trifunctional (meth)acrylates, tetrafunctional (meth)acrylates, etc. More specifically, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylenepropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tetra(meth)acrylate, Examples include tripentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, and tripentaerythritol octa(meth)acrylate.

[0054] The (meth)acrylate compound contained in the curable composition may consist of only one type of the aforementioned (meth)acrylate, or may consist of two or more types. From the perspective of improving scratch resistance, it is preferable that the (meth)acrylate compound contained in the curable composition includes a polyfunctional (meth)acrylate with five or more functionalities, and it is also preferable to increase the content of the polyfunctional (meth)acrylate with five or more functionalities.

[0055] In addition, it is preferable that the polyfunctional (meth)acrylates include dimers. Since the dimers of polyfunctional (meth)acrylates have excellent curing speed and can easily increase the curing rate of the curable composition, scratch resistance can be further improved. Among these, it is preferable to include at least one selected from the group consisting of dimers of pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate, and it is more preferable to include at least one selected from the group consisting of dimers of pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0056] In terms of scratch resistance, transparency, and solubility in solvents, it is preferable that the content of the above dimer be in the range of 25 mass% or more and 50 mass% or less based on the total solid content of the polyfunctional (meth)acrylate. More preferably, it is 30 mass% or more and 40 mass% or less.

[0057] Furthermore, the curable composition constituting the low refractive index layer (16) preferably contains a fluorine-containing (meth)acrylate as part of a (meth)acrylate compound having a reactive group. Then, high antifouling properties can be imparted to the anti-reflection film (10). Specific examples of fluorine-containing (meth)acrylates include (meth)acrylates containing perfluoropolyether groups. The perfluoropolyether group may be one in which all hydrogens in a polyether, such as polyethylene glycol or polypropylene glycol, are substituted with fluorine, and examples include a fluoropolyether group having a repeating structure formed by any one of perfluoromethylene oxide (-CF2O-), perfluoroethylene oxide (-CF2CF2O-), perfluoropropylene oxide (-CF2CF2CF2O-), or a combination of multiple of these. The number of repeating units of the above repeating structure is preferably 1 to 100. Specific compounds include "KY-1203", "KY-1207", "KY-1211", "KY-1216", "KY-1240" from Shin-Etsu Chemical Co., Ltd., "Megafac RS-75" from DIC, "Optool DAC-HP" and "Optool DAC-100" from Daikin Industrial Co., Ltd., and "Ftergent 601AD" and "Ftergent 601ADH2" from Neos. By using such fluorine-containing (meth)acrylates, the adhesion of contaminants or fingerprints can be suppressed, and contaminants or fingerprints can be easily removed.

[0058] It is preferable that the fluorine-containing (meth)acrylate does not have urethane bonds in its structure. Since the fluorine-containing (meth)acrylate does not have urethane bonds in its structure, the hardness of the low refractive index layer (16) is increased, thereby giving the low refractive index layer (16) particularly high wear resistance.

[0059] It is preferable that the content of fluorine-containing (meth)acrylate in the low refractive index layer (16) be 1.0 mass% or more and 15.0 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16). If the content of fluorine-containing (meth)acrylate in the low refractive index layer (16) is 1.0 mass% or more with respect to 100 mass% of the solid content of the low refractive index layer (16), the surface slipperiness of the low refractive index layer (16) is improved, thereby improving scratch resistance. In addition, antifouling properties are also improved. Furthermore, in this regard, the content of fluorine-containing (meth)acrylate in the low refractive index layer (16) is more preferably 3.0 mass% or more, and even more preferably 5.0 mass% or more with respect to 100 mass% of the solid content of the low refractive index layer (16). And, if the content of the fluorine-containing (meth)acrylate in the low refractive index layer (16) is 15.0 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16), the reduction in scratch resistance is suppressed. Also, in this regard, the content of the fluorine-containing (meth)acrylate in the low refractive index layer (16) is more preferably 13.0 mass% or less, and even more preferably 10.0 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16). Also, the solid content of the low refractive index layer (16) mentioned in this specification refers to the components excluding the liquid-type components at room temperature that are not immobilized in the binder resin in the low refractive index layer (16). The solid content of the low refractive index layer (160) includes alumina particles, hollow silica particles, binder resin, etc. Oil components as additives or surfactants not immobilized in the binder resin are not included.

[0060] Alumina particles are included in the low-refractive-index layer (16) to form a depression (convex portion) on the surface of the low-refractive-index layer (16). By forming a depression on the surface of the low-refractive-index layer (16) by the alumina particles, the low-refractive-index layer (16) can have good scratch resistance.

[0061] Alumina particles may be filled particles or hollow particles, but it is preferable that the alumina particles be filled particles. A filled particle is a particle that has no substantially empty space (cavity) inside the particle, and refers to a particle in which the ratio of empty space is less than 5% of the volume of the filled particle. A hollow particle is a particle that has empty space inside the particle, and refers to a particle in which the ratio of empty space is 5% or more of the volume of the hollow particle. When the alumina particles are filled particles, the scratch resistance of the low refractive index layer (16) is improved, and the scratch resistance of the anti-reflective film (10) is improved. On the other hand, when the alumina particles are hollow particles, the refractive index of the low refractive index layer (16) can be lowered to reduce light reflection. In the case of hollow particles, it is preferable that the ratio of empty space is 10% or more and 80% or less of the volume of the hollow particle. If the ratio of empty space is 10% or more, the refractive index can be lowered to reduce light reflection. More preferably, it is 20% or more, and even more preferably, 30% or more. Meanwhile, if the ratio of empty space is 80% or less, the decrease in the dispersibility of alumina particles can be suppressed. More preferably, it is 60% or less.

[0062] The shape of the alumina particles is not particularly limited and may be spherical, needle-shaped, flaky, rod-shaped, fibrous, irregular, etc. Among these, spherical is preferred.

[0063] Alumina particles are surface-treated with a silane coupling agent having reactive groups capable of forming bonds with (meth)acrylate compounds. Since the silane coupling agent has reactive groups capable of forming bonds with (meth)acrylate compounds, the alumina particles surface-treated with the aforementioned silane coupling agent can be firmly bonded with the (meth)acrylate contained in the low refractive index layer (16) and additionally bonded with reactive groups contained in a resin layer such as an adjacent hard coating layer (14). When these bonds are formed, the wear resistance and solvent resistance of the anti-reflective film (10) are improved.

[0064] Silane coupling agents generally have hydrolyzable groups and other functional groups bonded to silicon atoms within the molecule. Here, a hydrolyzable group refers to a substituent that is directly connected to a silicon atom and can form a siloxane bond through a hydrolysis reaction and / or a condensation reaction. Examples of hydrolyzable groups include halogen atoms, alkoxy groups, acyloxy groups, and alkenyloxy groups. If the hydrolyzable group has carbon atoms, it is preferable that the number of carbon atoms is 6 or less, and more preferable that it is 4 or less. In particular, an alkoxy group with 4 or fewer carbon atoms or an alkenyloxy group with 4 or fewer carbon atoms is preferred. The alumina particles are surface-treated by the hydrolyzable group undergoing hydrolysis and forming bonds between the surface oxygen atoms of the alumina particles.

[0065] The silane coupling agent used here includes a reactive group capable of forming a bond with a (meth)acrylate compound in addition to the aforementioned hydrolytic group. Examples of reactive groups include groups having carbon-carbon unsaturated double bonds such as (meth)acryloyl groups, vinyl groups, styryl groups, and allyl groups, as well as ring-opening polymerizable groups such as epoxy groups and oxetanyl groups. These reactive groups are ultraviolet reactive. In a low refractive index layer (16) containing alumina particles surface-treated with a (meth)acrylate compound having a reactive group and a silane coupling agent having a reactive group, the reactive group of the (meth)acrylate compound reacts with the reactive group of the silane coupling agent to form a bond.

[0066] Examples of silane coupling agents having a carbon-carbon unsaturated double bond group as a reactive group include p-styryl trimethoxysilane, 2-(aryloxymethyl)acrylic acid (trimethoxysilyl)propyl, 3-acryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyldiethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-methacryloxypropyl methyldimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, p-styryl trimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 7-octenyl trimethoxysilane, etc.

[0067] Examples of silane coupling agents having a ring-opening polymerizable group as a reactive group include 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, etc.

[0068] Among these, in terms of reactivity with (meth)acrylate compounds, it is preferable to use a silane coupling agent having a carbon-carbon unsaturated double bond group, and in particular, a silane coupling agent having an ethylenically carbon-carbon double bond group such as a (meth)acryloyl group, vinyl group, styryl group, or allyl group is even more preferable.

[0069] The content of the silane coupling agent is preferably in the range of 1 part by mass or more and 50 parts by mass or less per 100 parts by mass of alumina particles. Then, the effect of surface treatment by the silane coupling agent can be improved. In addition, wear resistance and solvent resistance can be improved while maintaining high scratch resistance of the low refractive index layer (16). More preferably, the content is 10 parts by mass or more and 40 parts by mass or less. Silane coupling agents that are not bonded to the alumina particles may remain in the low refractive index layer (16), and the preferred content range described in this specification refers to the content as the total silane coupling agent, including the silane coupling agents that are not bonded to these alumina particles.

[0070] In order to form a recess (convexity) on the surface of the low-refractive-index layer (16) and obtain good scratch resistance, the difference (rd) between the average particle diameter (r) of the alumina particles and the thickness (d) of the low-refractive-index layer (16) is preferably 10 nm or more. The difference (rd) is more preferably 15 nm or more, and even more preferably 18 nm or more. Meanwhile, from the viewpoint of maintaining transparency by suppressing the height of the formed recess, the difference (rd) is 300 nm or less. More preferably 200 nm or less, and even more preferably 100 nm or less.

[0071] The average particle diameter (r) of the alumina particles is preferably within the range of 60 nm or more and 400 nm or less, although it varies depending on the thickness (d) of the low refractive index layer (16). More preferably, it is 70 nm or more, and even more preferably 90 nm or more. Also, more preferably, it is 300 nm or less, and even more preferably 200 nm or less. The average particle diameter (r) of the alumina particles is the average arithmetic value based on volume obtained by the laser diffraction scattering method according to JIS Z8825, and includes not only the primary particle diameter but also the secondary particle diameter, which is an aggregate of particles.

[0072] The content of alumina particles in the low refractive index layer (16) is preferably 0.1 mass% or more and 6.0 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16). Excellent scratch resistance can be obtained if the content of alumina particles in the low refractive index layer (16) is 0.1 mass% or more with respect to 100 mass% of the solid content of the low refractive index layer (16). In addition, from this perspective, the content of alumina particles in the low refractive index layer (16) is more preferably 1.0 mass% or more, and even more preferably 2.0 mass% or more with respect to 100 mass% of the solid content of the low refractive index layer (16). Furthermore, high transparency can be obtained if the content of alumina particles in the low refractive index layer (16) is 6.0 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16). In addition, from this perspective, the content of alumina particles in the low refractive index layer (16) is more preferably 5.5 mass% or less, and even more preferably 5.0 mass% or less, with respect to 100 mass% of the solid content of the low refractive index layer (16).

[0073] Hollow silica particles are particles with an average particle diameter smaller than the average thickness (d) of the low refractive index layer (16). It is preferable that hollow silica particles have an average particle diameter smaller than that of alumina particles that form a recess (convexity) on the surface of the low refractive index layer (16). Hollow silica particles are particles that do not substantially contribute to the formation of surface irregularities on the low refractive index layer (16). Hollow silica particles refer to particles that have empty spaces (cavities) inside the particles, with the ratio of empty spaces being 5% or more of the volume. A hollow refers to a cell structure consisting of an outer shell and an internal empty space (cavity), or a porous structure having multiple empty spaces (cavities). Because hollow silica particles have a hollow structure, they can reduce light reflection by lowering the refractive index of the low refractive index layer (16). The shape of the hollow silica particles is not particularly limited, but spherical, spindle-shaped, egg-shaped, flat, cubic, and irregular shapes are preferred. Among these, spherical, flat, and cubic shapes are particularly desirable.

[0074] In hollow silica particles, it is preferable that the ratio of empty space (cavities) be 10% or more and 80% or less of the volume. If the ratio of empty space is 10% or more of the volume, the refractive index can be lowered to reduce light reflection. More preferably, it is 20% or more of the volume, and even more preferably 30% or more of the volume. On the other hand, if the ratio of empty space is 80% or less of the volume, the decrease in dispersibility of the hollow silica particles can be suppressed. More preferably, it is 60% or less of the volume.

[0075] The average particle diameter of the hollow silica particles is preferably 5 nm or more and 100 nm or less, although this varies depending on the thickness (d) of the low refractive index layer (16). More preferably, it is 20 nm or more, and even more preferably 40 nm or more. Furthermore, more preferably, it is 80 nm or less, and even more preferably 70 nm or less. If the average particle diameter of the hollow silica particles is within this preferred range, excellent anti-reflection effect and transparency can be obtained in the low refractive index layer (16). The average particle diameter is the average arithmetic value based on volume obtained by the laser diffraction scattering method according to JIS Z8825. It includes not only the primary particle diameter but also the secondary particle diameter, which is an aggregate of particles.

[0076] It is preferable that the refractive index of the hollow silica particles be within the range of 1.01 to 1.45. More preferably, it is within the range of 1.15 to 1.38, and even more preferably, within the range of 1.15 to 1.35. If the refractive index of the hollow silica particles is within this range, an excellent anti-reflection effect can be obtained.

[0077] The content of hollow silica particles in the low refractive index layer (16) is preferably 6.0 mass% or more and 49.9 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16). If the content of hollow silica particles in the low refractive index layer (16) is 6.0 mass% or more with respect to 100 mass% of the solid content of the low refractive index layer (16), excellent anti-reflection properties can be obtained. Furthermore, from this perspective, the content of hollow silica particles in the low refractive index layer (16) is more preferably 10 mass% or more, even more preferably 20 mass% or more, and particularly preferably 30 mass% or more with respect to 100 mass% of the solid content of the low refractive index layer (16). And, if the content of hollow silica particles in the low refractive index layer (16) is 49.9 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16), the decrease in scratch resistance is suppressed. Also, from this perspective, the content of hollow silica particles in the low refractive index layer (16) is more preferably 45 mass% or less, and even more preferably 40 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16).

[0078] In addition, the total amount of alumina particles and hollow silica particles in the low refractive index layer (16) is preferably 10 mass% or more and 50 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16). Excellent scratch resistance can be obtained if the total amount of alumina particles and hollow silica particles in the low refractive index layer (16) is 10 mass% or more with respect to 100 mass% of the solid content of the low refractive index layer (16). Furthermore, from this perspective, the total amount of alumina particles and hollow silica particles in the low refractive index layer (16) is more preferably 20 mass% or more, and even more preferably 30 mass% or more with respect to 100 mass% of the solid content of the low refractive index layer (16). Meanwhile, if the total amount of alumina particles and hollow silica particles in the low refractive index layer (16) is 50 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16), excellent scratch resistance can be obtained because the low refractive index layer (16) can sufficiently retain alumina particles and hollow silica particles. In addition, from this perspective, the total amount of alumina particles and hollow silica particles in the low refractive index layer (16) is more preferably 45 mass% or less, and even more preferably 40 mass% or less with respect to 100 mass% of the solid content of the low refractive index layer (16).

[0079] The low refractive index layer (16) is formed using an ionizing radiation curable composition comprising a (meth)acrylate compound having reactive groups, alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming bonds with the (meth)acrylate compound, and hollow silica particles. In the low refractive index layer (16), bonds are formed through reactive groups between the (meth)acrylate compounds, between the surface-treated alumina particles, between the (meth)acrylate compounds and the surface-treated alumina particles, and between the (meth)acrylate compounds or the surface-treated alumina particles and components having reactive groups included in the adjacent layer through ionizing radiation irradiation, thereby the low refractive index layer (16) has high scratch resistance, abrasion resistance, and solvent resistance. As previously mentioned, it is preferable that the reactive groups contained in the (meth)acrylate compounds and the silane coupling agent are ultraviolet reactive. If the (meth)acrylic compound and the alumina particles have reactive groups that are reactive to ultraviolet rays, then by performing ultraviolet irradiation on the low refractive index layer (16) formed from a composition including the (meth)acrylic compound and the surface-treated alumina particles, the scratch resistance, wear resistance, and solvent resistance of the low refractive index layer (16) are improved, thereby improving the scratch resistance, wear resistance, and solvent resistance of the anti-reflection film (10).

[0080] Additionally, the composition for forming the low refractive index layer (16) preferably includes a photopolymerization initiator when the (meth)acrylic compound has a reactive group that is reactive to ultraviolet light (in the case of a UV-curable resin). Furthermore, the composition for forming the low refractive index layer (16) may contain a solvent as needed (a solvent used as a dispersion medium in a particle dispersion of alumina particles, and / or a solvent added separately therefrom). The binder resin of the low refractive index layer (16) may be composed solely of a UV-curable resin such as a (meth)acrylic resin, or may be composed of a combination of a UV-curable resin and a non-UV-curable resin. As for the non-UV-curable resin, the photopolymerization initiator, and the solvent, the chemical species described above as specific examples that may be contained in the composition for forming the hard coating layer (14) can be appropriately applied in the composition for forming the low refractive index layer (16).

[0081] The content of the photopolymerization initiator is preferably in the range of 0.1 mass% or more and 10 mass% or less based on the total amount of solids of the composition for forming the low refractive index layer (16). More preferably, it is 1 mass% or more and 5 mass% or less.

[0082] In addition, the low refractive index layer (16) may contain additives as needed. Examples of such additives include dispersants, leveling agents, defoaming agents, thixotropic agents, antibacterial agents, flame retardants, slip agents, refractive index modifiers, inorganic particles other than alumina particles, resin particles, etc. When inorganic particles other than alumina particles are included, these inorganic particles may also be surface-treated with a silane coupling agent having a reactive group capable of forming a bond with a (meth)acrylate compound, just like alumina particles.

[0083] In this embodiment, the surface water contact angle of the anti-reflection film (10), that is, the surface water contact angle of the low refractive index layer (16), is 100° or more. By doing so, the anti-reflection film (10) has high antifouling properties. In addition, the surface slipperiness of the low refractive index layer (16) is improved, contributing to improved scratch resistance. The surface water contact angle of the low refractive index layer (16) is preferably 105° or more, and even more preferably 110° or more, from the perspective of obtaining higher antifouling properties. The surface water contact angle of the low refractive index layer (16) depends on the composition of the constituent material of the low refractive index layer (16). For example, by including fluorine-containing (meth)acrylate or silicon-containing (meth)acrylate in the low refractive index layer (16), the water contact angle is increased. Additionally, the surface water contact angle of the low refractive index layer (16) can be increased by imparting fine irregularities to the surface of the low refractive index layer (16), and in this embodiment, alumina particles contained in the low refractive index layer (16) can perform this role. However, imparting irregularities to the surface of the low refractive index layer (16) may reduce the surface cleaning performance (wiping performance), so in order to reduce this possibility, it is preferable to increase the water contact angle by using a method of adding fluorine-containing (meth)acrylate or silicon-containing (meth)acrylate instead of the method of imparting irregularities, or in addition to that method. There is no specific upper limit for the surface water contact angle of the low refractive index layer (16), but it is generally 130° or less.

[0084] The refractive index of the low refractive index layer (16) is lower than that of the hard coating layer (14) and is not particularly limited, but is preferably 1.35 or higher and 1.52 or lower. If the refractive index is 1.35 or higher, sufficient strength of the low refractive index layer (16) can be secured, and good scratch resistance can be obtained. On the other hand, if the refractive index is 1.52 or lower, the anti-reflection film (10) can be made to have a lower reflectivity. From the above perspective, the refractive index of the low refractive index layer (16) is more preferably 1.38 or higher and 1.50 or lower, and also preferably 1.40 or higher and 1.49 or lower.

[0085] The average thickness (d) of the low refractive index layer (16) is preferably within the range of 80 nm or more and 110 nm or less. More preferably, it is 85 nm or more, and even more preferably 90 nm or more. Also, more preferably, it is 105 nm or less, and even more preferably 100 nm or less. Within this range, a good low luminous reflectance can be obtained and light reflection can be reduced. The thickness of the low refractive index layer (16) is the thickness of the relatively smooth portion of the part without irregularities caused by alumina particles in the thickness direction.

[0086] (Method for manufacturing anti-reflective film)

[0087] To manufacture an anti-reflection film (10), a hard coating layer (14) and a low refractive index layer (16) can be formed in this order on the surface of a substrate film (12). To form each layer, a composition for forming each layer is applied, and if necessary, after drying, curing is performed in a manner suitable for the curability of the composition, such as irradiation with ionizing radiation including ultraviolet rays. After forming a specific layer, a composition for forming the next layer is applied, and if necessary, after drying, the composition is cured. By repeating this process sequentially, a laminated structure of a hard coating layer (14) and a low refractive index layer (16) can be formed and an anti-reflection film (10) can be manufactured.

[0088] For the application of the composition forming each layer, a wet method can be appropriately used. Specifically, various coating methods such as reverse gravure coating, direct gravure coating, die coating, bar coating, wire bar coating, roll coating, spin coating, dip coating, spray coating, knife coating, and kiss coating, or various printing methods such as inkjet, offset printing, screen printing, and flexographic printing can be used.

[0089] The drying process for each layer is not particularly limited as long as it can remove the solvent used in the coating solution, but it is preferable to perform it at a temperature of 50 to 150°C for about 10 to 180 seconds.

[0090] For ultraviolet irradiation of each layer, high-pressure mercury lamps, electrodeless (microwave type) lamps, xenon lamps, metal halide lamps, and any other ultraviolet irradiation device may be used. If necessary, ultraviolet irradiation may be performed under an inert gas atmosphere such as nitrogen. The amount of ultraviolet irradiation is not particularly limited, but 50 to 800 mJ / ㎠ is preferred, and 100 to 300 mJ / ㎠ is more preferred.

[0091] When forming a hard coating layer (14) on the surface of a substrate film (12), a surface treatment may be performed on the surface of the substrate film (12) before application to improve the adhesion between the substrate film (12) and the hard coating layer (14). Examples of surface treatments include corona treatment, plasma treatment, hot air treatment, ozone treatment, ultraviolet treatment, etc.

[0092] (Characteristics of anti-reflective film)

[0093] An anti-reflection film (10) having the above composition comprises a base film (12), a hard coating layer (14) formed on the surface of the base film (12), and a low refractive index layer (16) formed on the surface of the hard coating layer (14). The low refractive index layer (16) is composed of a cured product of an ionizing radiation curable composition comprising a (meth)acrylate compound having reactive groups, hollow silica particles, and alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming bonds with the (meth)acrylate compound. Since the water contact angle of the surface of the anti-reflection film (10) is 100° or more, it has excellent scratch resistance, as well as high anti-fouling properties, wear resistance, and solvent resistance.

[0094] In the anti-reflection film (10) according to the present embodiment, the water contact angle of the surface is 100° or more, so the anti-reflection film (10) has high antifouling properties. Since the anti-reflection film (10) has high antifouling properties, contaminants such as fingerprints are difficult to adhere to the surface of the anti-reflection film (10), and even if they do adhere, they can be easily removed. In addition, in the anti-reflection film (10) according to the present embodiment, alumina particles contained in the low refractive index layer (16) contribute to the scratch resistance of the anti-reflection film (10). Furthermore, as previously mentioned, the alumina particles are surface-treated, and the formation of a bond between the alumina particles and the (meth)acrylate compound contributes to the improvement of wear resistance and solvent resistance. Thus, the anti-reflection film (10) according to the present embodiment has high scratch resistance, wear resistance, and solvent resistance in addition to high anti-reflection and antifouling properties, so it is particularly suitable for applications that receive frequent contact with fingers, such as being placed on the surface of a touch panel. Since the anti-reflection film (10) has high solvent resistance, even when the surface of the anti-reflection film (10) is rubbed with a cloth or finger soaked in a solvent such as alcohol for cleaning or sterilization, it can maintain a surface condition with high scratch resistance or wear resistance.

[0095] The haze of the anti-reflective film (10) is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.0 or less, in terms of good visibility. The visual reflectance of the anti-reflective film (10) is preferably lower, more preferably 2.5% or less, and even more preferably 2.0% or less. If the visual reflectance is 2.0% or less, the anti-reflective film (10) can be considered to have sufficiently high anti-reflectivity.

[0096] The arithmetic mean roughness (roughness; Ra) of the surface of the low refractive index layer (16) is preferably within the range of 1.0 nm to 20 nm for the sake of compatibility with scratch resistance and wear durability. More preferably, it is 3.0 nm to 15 nm, and even more preferably 5.0 nm to 10 nm.

[0097] <Anti-reflective film of the second embodiment>

[0098] FIG. 2 illustrates an anti-reflection film (20) according to a second embodiment. The anti-reflection film (20) according to the second embodiment has a base film (12), a hard coating layer (14) formed on a surface of the base film (12), a low refractive index layer (16) formed on a surface of the hard coating layer (14), and an anti-fouling layer (18) formed on a surface of the low refractive index layer (16).

[0099] The anti-reflection film (20) according to the second embodiment differs from the anti-reflection film (10) according to the first embodiment in that it has an anti-fouling layer (18) on the surface of the low refractive index layer (16). Except for this, it is identical to the anti-reflection film (10) according to the first embodiment, and description of identical components is omitted.

[0100] (Antifouling layer)

[0101] In the anti-reflection film (20) according to the present embodiment, an antifouling layer (18) is provided on the surface of the low refractive index layer (16). The antifouling layer (18) serves to improve the antifouling properties of the anti-reflection film (20).

[0102] The antifouling layer (18) is composed of a cured product of an ionizing radiation-curable composition containing fluorine-containing (meth)acrylate. In particular, it is preferred to be composed of a cured product of an ultraviolet-curable composition.

[0103] By making the antifouling layer (18) composed of a cured product of a composition containing a fluorine-containing (meth)acrylate, the anti-reflective film (20) having the antifouling layer (18) on its surface exhibits excellent antifouling properties, solvent resistance, wear resistance, and scratch resistance. Specific examples of fluorine-containing (meth)acrylates include (meth)acrylates containing perfluoropolyether groups. Perfluoropolyether groups refer to polyethers such as polyethylene glycol or polypropylene glycol in which all hydrogen atoms are substituted with fluorine. Examples include fluoropolyether groups having a repeating structure formed by any one of perfluoromethylene oxide (-CF2O-), perfluoroethylene oxide (-CF2CF2O-), perfluoropropylene oxide (-CF2CF2CF2O-), or a combination of multiple of these. The number of repeating units of the repeating structure is preferably 1 to 100. Specific compounds include Shin-Etsu Chemical Co. products "KY-1203", "KY-1207", "KY-1211", "KY-1216", "KY-1240", DIC product "Megafac RS-75", Daikin Industrial Co. products "Optool DAC-HP", "Optool DAC-100", Neos product "Ftagent 601AD", "Ftagent 601ADH2".

[0104] It is preferable that the fluorine-containing (meth)acrylate does not have urethane bonds in its structure. By the fact that the fluorine-containing (meth)acrylate does not have urethane bonds in its structure, the hardness of the antifouling layer (18) is increased, and the antifouling layer (18) is given particularly high wear resistance.

[0105] In the antifouling layer (18), it is preferable that the content of fluorine-containing (meth)acrylate be 90 mass% or more based on the total solid content of the antifouling layer (18). By doing so, a high antifouling effect can be obtained through the fluorine-containing (meth)acrylate. From the perspective of further enhancing the antifouling effect, it is more preferable that the content of fluorine-containing (meth)acrylate in the antifouling layer (18) be 92 mass% or more based on the total solid content of the antifouling layer (18). Furthermore, it is even more preferable that the total amount of the resin component constituting the antifouling layer (18), excluding unavoidable components, is fluorine-containing (meth)acrylate. The solid content of the antifouling layer (18) mentioned in this specification is a component excluding the liquid-type component at room temperature that is not immobilized on the curable component in the antifouling layer (18). The solid components of the antifouling layer (18) include fluorine-containing (meth)acrylate, etc.

[0106] The antifouling layer (18) can be formed using a composition containing a fluorine-containing (meth)acrylate. The composition for forming the antifouling layer (18) is placed in a layer form on the surface of the low refractive index layer (16) and then cured. When the antifouling layer (18) is formed as a cured product of a composition having UV curability, it is preferable that the composition for forming the antifouling layer (18) additionally contain a photopolymerization initiator. Additionally, a solvent may be included if necessary.

[0107] As for the photopolymerization initiator and solvent, the chemical species described as specific examples that can be contained in the previously mentioned composition for forming the hard coating layer (14) can be appropriately applied in the composition for forming the antifouling layer (18). The content of the photopolymerization initiator is preferably in the range of 0.1 mass% or more and 15 mass% or less based on the total amount of solids in the composition for forming the antifouling layer (18). More preferably, it is 3 mass% or more and 10 mass% or less.

[0108] In addition, the antifouling layer (18) may include additives as needed. Examples of such additives include antifouling agents other than fluorine-containing (meth)acrylates, dispersants, leveling agents, defoaming agents, thixotropic agents, antibacterial agents, flame retardants, slip agents, refractive index adjusting agents, etc. However, from the perspective of improving the surface smoothness of the antifouling layer (18), it is preferable that the antifouling layer (18) does not contain solid particles, such as metal oxide particles like alumina particles or hollow silica particles. Even if the antifouling layer (18) contains solid particles, it is preferable to limit the particle diameter of the solid particles to 10 nm or less, and the content of the solid particles to 1 mass% or less relative to 100 mass% of the solid content of the antifouling layer (18).

[0109] In this embodiment, the surface water contact angle of the anti-reflection film (20), that is, the surface water contact angle of the anti-fouling layer (18), is set to be 100° or more. As a result, the anti-reflection film (20) has high anti-fouling properties. In addition, the surface slipperiness of the anti-fouling layer (18) is improved, contributing to improved scratch resistance. The surface water contact angle of the anti-fouling layer (18) is preferably 105° or more, more preferably 110° or more, from the perspective of obtaining higher anti-fouling properties. The surface water contact angle of the anti-fouling layer (18) is increased, for example, by increasing the content of fluorine-containing (meth)acrylate in the anti-fouling layer (18). There is no specific upper limit for the surface water contact angle of the anti-fouling layer (18), but it is generally 130° or less.

[0110] It is preferable that the thickness of the antifouling layer (18) be 1 nm or more. Then, a high antifouling effect is obtained by the antifouling layer (18). More preferably, the thickness of the antifouling layer (18) is 3 nm or more, and even more preferably 5 nm or more. Meanwhile, it is preferable that the thickness of the antifouling layer (18) be 15 nm or less. Then, the anti-reflection properties of the anti-reflection film (20) can be maintained at a high level. More preferably, the thickness of the antifouling layer (18) is 10 nm or less.

[0111] It is preferable that the refractive index of the antifouling layer (18) be 1.6 or less. If it is 1.6 or less, the anti-reflection properties of the anti-reflection film (20) can be maintained at a high level. More preferably, the refractive index of the antifouling layer (18) is 1.55 or less, and even more preferably 1.50 or less. Meanwhile, the refractive index of the antifouling layer (18) is not particularly limited as long as the thickness of the antifouling layer (18) is within the range described above, but it is preferably 1.3 or more, and more preferably 1.35 or more.

[0112] The arithmetic mean roughness (roughness; Ra) of the surface of the antifouling layer (18) is preferably within the range of 1.0 nm to 20 nm for the sake of compatibility with scratch resistance and wear durability. More preferably, it is 3.0 nm to 15 nm, and even more preferably 5.0 nm to 10 nm.

[0113] In the anti-reflection film (20) according to the present embodiment, the composition of the low refractive index layer (16) may be the same as the composition of the anti-reflection film (10) according to the first embodiment. However, unlike the anti-reflection film (10) according to the first embodiment, an antifouling layer (18) is provided on the low refractive index layer (16), and since the antifouling layer (18) exhibits high antifouling properties, there is no need to include a fluorine-containing compound in the low refractive index layer (16) for the purpose of improving antifouling properties. If a large amount of a fluorine-containing compound is included in the low refractive index layer (16), the wettability with the composition for forming the antifouling layer (18) is reduced, and the adhesion with the antifouling layer (18) is weakened, which leads to a decrease in the scratch resistance of the anti-reflection film (20). However, if the low refractive index layer (16) is not made to include a fluorine-containing compound, the scratch resistance of the anti-reflection film (20) can be improved. Even when a fluorine-containing compound is included in the low refractive index layer (16), it is preferable to limit the content to 1 mass% or less relative to 100 mass% of the solid content of the low refractive index layer (16).

[0114] In the anti-reflection film (20) according to the present embodiment, an antifouling layer (18) is provided in direct contact with the surface of the low refractive index layer (16). For example, a primer layer having an adhesion-enhancing effect, such as a layer made of a fluorine-free (meth)acrylate resin, is not formed on the surface of the low refractive index layer (16). By not providing such a primer layer, the composition of the anti-reflection film (20) can be simplified, and the productivity and cost-suppression effects of the anti-reflection film (20) can be increased.

[0115] <Other types of anti-reflective films>

[0116] The anti-reflection film according to the present invention is, as described above, a hard coating layer (14) and a low refractive index layer (16) are laminated in this order on the surface of a substrate film (12), and furthermore, an antifouling layer (18) is optionally laminated. However, as long as the low refractive index layer (16) has a predetermined composition, it is not limited to the composition of the anti-reflection film (10) according to the first embodiment or the anti-reflection film (20) according to the second embodiment described above. Other embodiments of the anti-reflection film according to the present invention are exemplified below.

[0117] (Third embodiment)

[0118] FIG. 3 illustrates an anti-reflection film (30) according to a third embodiment. The anti-reflection film (30) according to the third embodiment has a base film (12), a hard coating layer (14) formed on the surface of the base film (12), a high refractive index layer (15) formed on the surface of the hard coating layer (14), and a low refractive index layer (16) formed on the surface of the high refractive index layer (15).

[0119] The anti-reflection film (30) according to the third embodiment differs from the anti-reflection film (10) according to the first embodiment in that it has a high refractive index layer (15) between the hard coating layer (14) and the low refractive index layer (16). Other than that, it is identical to the anti-reflection film (10) according to the first embodiment, and the description of the identical components is omitted.

[0120] The high refractive index layer (15) is a layer having a higher refractive index than the hard coating layer (14) and the low refractive index layer (16). By installing the high refractive index layer (15) between the hard coating layer (14) and the low refractive index layer (16), a high anti-reflection effect is achieved in the anti-reflection film (30). The refractive index of the high refractive index layer (15) is preferably within the range of 1.55 or higher and 1.80 or lower. More preferably, it is 1.60 or higher and 1.70 or lower.

[0121] The constituent material of the high refractive index layer (15) is not particularly limited, and any known material conventionally used in anti-reflective films, etc., can be used to obtain a predetermined refractive index. For example, the material that can be used for the hard coating layer (14) or the low refractive index layer (16) can be appropriately selected from the materials described above. The refractive index of the high refractive index layer (15) can be adjusted by the type and amount of binder resin, inorganic oxide particles, and resin particles. For example, by adding a sufficient amount of inorganic oxide particles, a high refractive index layer (15) with a higher refractive index than the low refractive index layer (16) can be formed.

[0122] The average thickness of the high refractive index layer (15) varies depending on the setting of the refractive index, but, for example, by making it 50 nm or more and 200 nm or less, the anti-reflection function can be further enhanced. As for the high refractive index layer (15), two or more layers with different refractive indices may be stacked and arranged.

[0123] (Fourth embodiment)

[0124] FIG. 4 illustrates an anti-reflection film (40) according to a fourth embodiment. The anti-reflection film (40) according to the fourth embodiment has a base film (12), a hard coating layer (14) formed on one side of the base film (12), and a low refractive index layer (16) formed on the side of the hard coating layer (14). Additionally, it has a transparent adhesive layer (22) on the other side of the base film (12). A release film (24) is disposed on the side of the transparent adhesive layer (22) as needed. The release film (24) functions as a protective layer for the transparent adhesive layer (22) before use of the anti-reflection film (40), and is peeled off from the transparent adhesive layer (22) when the anti-reflection film (40) is used.

[0125] The anti-reflection film (40) according to the fourth embodiment is different from the anti-reflection film (10) according to the first embodiment in that it has a transparent adhesive layer (22) on the other side of the base film (12), and otherwise is identical to the anti-reflection film (10) according to the first embodiment, and the description of the identical components is omitted.

[0126] The transparent adhesive layer (22) is intended to adhere the anti-reflection film (40) to the surface of a display or the like with good adhesion. In addition, the anti-reflection film (40) has the effect of preventing glass shattering by having the transparent adhesive layer (22). That is, the anti-reflection film (40) also functions as a shatter-prevention film.

[0127] The adhesive composition forming the transparent adhesive layer (22) may contain known adhesive resins such as acrylic adhesives, silicone adhesives, and urethane adhesives. Among these, acrylic adhesives are preferred from the perspective of optical transparency and heat resistance. The adhesive composition preferably contains a crosslinking agent to improve the cohesiveness of the transparent adhesive layer (22). Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and chelate-based crosslinking agents.

[0128] The adhesive composition may include additives as needed. Examples of known additives include plasticizers, silane coupling agents, surfactants, antioxidants, fillers, curing accelerators, and curing retarders. Additionally, for reasons such as productivity, it may be diluted using an organic solvent.

[0129] The thickness of the transparent adhesive layer (22) is not particularly limited, but it is preferably within the range of 5 μm or more and 100 μm or less. More preferably, it is 10 μm or more and 50 μm or less.

[0130] The transparent adhesive layer (22) can be formed by a method of directly applying an adhesive composition to the other side of the base film (12), a method of applying an adhesive composition to the surface of a release film (24) and then transferring it to the other side of the base film (12), a method of applying an adhesive composition to the surface of a first release film and then bonding a second release film and peeling off one of the release films and transferring it to the other side of the base film (12), etc.

[0131] In terms of preventing glass shattering, it is preferable that the transparent adhesive layer (22) has an adhesive strength of 4 N / 25 mm or more on glass. More preferably, it is 6 N / 25 mm or more, and even more preferably 10 N / 25 mm or more.

[0132] (Fifth embodiment)

[0133] FIG. 5 illustrates an anti-reflection film (50) according to a fifth embodiment. The anti-reflection film (50) according to the fifth embodiment comprises a base film (12), a hard coating layer (14) formed on one side of the base film (12), a low refractive index layer (16) formed on the surface of the hard coating layer (14), and a protective film (28) provided (placed) by interposing (through) an adhesive layer (26) on the surface of the low refractive index layer (16). Additionally, a transparent adhesive layer (22) is provided on the other side of the base film (12). A release film (24) is disposed on the surface of the transparent adhesive layer (22) as needed.

[0134] The anti-reflection film (50) according to the fifth embodiment is different from the anti-reflection film (40) according to the fourth embodiment in that it has a protective film (28) by interposing (through) an adhesive layer (26) on the surface of the low refractive index layer (16), and otherwise is identical to the anti-reflection film (40) according to the fourth embodiment, and the description of the identical components is omitted.

[0135] The protective film (28) can suppress scratches on the surface of the low refractive index layer (16) when handling the anti-reflection film (50), such as through a roll process or bonding to a display. The protective film (28) is attached to the surface of the low refractive index layer (16) through an adhesive layer (26). After processing the anti-reflection film (50), the protective film (28) is peeled off from the surface of the low refractive index layer (16) together with the adhesive layer (26). To this end, the adhesive layer (26) is adjusted such that the adhesive force between the protective film (28) and the adhesive layer (26) is stronger than the adhesive force between the low refractive index layer (16) and the adhesive layer (26), and the adhesive force between the low refractive index layer (16) and the adhesive layer (26) is adjusted to an adhesive force that allows for interfacial peeling. In the anti-reflection film (50) according to the present embodiment, the water contact angle of the surface is defined for the surface in a state where the protective film (28) and the adhesive layer (26) have been peeled off, and the water contact angle on the surface where they have been peeled off is 100° or more.

[0136] The material constituting the protective film (28) can be appropriately selected from the material exemplified as constituting the substrate film (12). The thickness of the protective film (28) is not particularly limited, but can be within the range of 2 μm or more and 500 μm or less, or within the range of 2 μm or more and 200 μm or less.

[0137] As for the adhesive layer (26), the one described in Patent Document 1 may be appropriately applied. The adhesive forming the adhesive layer (26) is not particularly limited, and acrylic adhesives, silicone adhesives, urethane adhesives, etc., may be appropriately used. In particular, acrylic adhesives are suitable because they have excellent transparency and heat resistance. It is preferable that the acrylic adhesive be formed from an adhesive composition comprising a (meth)acrylic polymer and a crosslinking agent.

[0138] (Meta)acrylic polymers are homopolymers or copolymers of (meth)acrylic monomers. Examples of (meth)acrylic monomers include alkyl group-containing (meth)acrylic monomers, carboxyl group-containing (meth)acrylic monomers, hydroxyl group-containing (meth)acrylic monomers, etc.

[0139] Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, metal chelate-based crosslinking agents, metal alkoxide-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and melamine-based crosslinking agents. One of these crosslinking agents may be used alone, or two or more may be used in combination.

[0140] The adhesive composition may include other additives in addition to (meth)acrylic polymers and crosslinking agents. Examples of other additives include crosslinking accelerators, crosslinking retarders, tackifiers, antistatic agents, silane coupling agents, plasticizers, release aids, pigments, dyes, wetting agents, thickeners, UV absorbers, preservatives, antioxidants, metal inerts, alkylating agents, flame retardants, etc. These are appropriately selected and used according to the application or purpose of the adhesive.

[0141] The thickness of the adhesive layer (26) is not particularly limited, but is preferably within the range of 1 μm or more and 10 μm or less. More preferably, it is 2 μm or more and 7 μm or less.

[0142] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible within the scope of the spirit of the invention.

[0143] For example, in the above-described embodiment, it is stated that a surface treatment may be performed on the surface of the base film (12), but a configuration in which an adhesive layer is provided (installed) on the surface of the base film (12) instead of a surface treatment is also acceptable.

[0144] The high refractive index layer (15) of the third embodiment is shown as being added to the anti-reflection film (10) of the first embodiment shown in FIG. 1, as shown in FIG. 3, but it is also acceptable for it to be added to the anti-reflection film (20) of the second embodiment shown in FIG. 2. Also, the transparent adhesive layer (22) and release film (24) of the fourth embodiment are shown as being added to the anti-reflection film (10) of the first embodiment shown in FIG. 1, as shown in FIG. 4, but it is also acceptable for them to be added to the anti-reflection film (20) of the second embodiment shown in FIG. 2 or the anti-reflection film (30) of the third embodiment shown in FIG. 3. Additionally, the adhesive layer (26) and protective film (28) according to the aforementioned fifth embodiment are shown as being added to the anti-reflection film (40) of the fourth embodiment shown in FIG. 4, as shown in FIG. 5, but they may also be added to the anti-reflection film (10) of the first embodiment shown in FIG. 1, the anti-reflection film (20) of the second embodiment shown in FIG. 2, or the anti-reflection film (30) of the third embodiment shown in FIG. 3. When the adhesive layer (26) and protective film (28) are added to the anti-reflection film (20) of the second embodiment, the adhesive layer (26) has a stronger adhesive force between the protective film (28) and the adhesive layer (26) than the adhesive force between the anti-fouling layer (18) and the adhesive layer (26), and the adhesive force between the anti-fouling layer (18) and the adhesive layer (26) is adjusted to an adhesive force that allows for interfacial peeling.

[0145] In addition, various functional layers, such as a gas barrier enhancing layer, an antistatic layer, and an oligomer block layer, may be placed in advance on the surface of the base film (12) before forming each layer. As for the antistatic layer, the one described in Patent Document 1 may be appropriately applied.

[0146] The present invention will be described in detail below using examples and comparative examples. Unless specifically stated below, the preparation and evaluation of samples were carried out at room temperature and in the atmosphere.

[0147] <Preparation of a composition for forming a hard coating layer>

[0148] To the UV-curable resin composition ESS-620 (manufactured by DIC; urethane acrylate resin, solvent (ethyl acetate); solid content concentration 79 mass%), the photopolymerization initiator "Omnirad 127" (manufactured by IGM Resins BV) was added at 3 mass% relative to the total solid content of the composition for forming a hard coating layer. Additionally, ethyl acetate was added to achieve a solid content concentration of 31 mass% to prepare a composition for forming a hard coating layer.

[0149] <Preparation of a composition for forming a high refractive index layer>

[0150] A composition for forming a high refractive index layer was prepared by adding methyl ethyl ketone to the UV-curable resin composition TYZ65-01 (manufactured by Toyo Chemical; acrylic resin, zirconium oxide (average particle diameter 80 nm), photopolymerization initiator (the above "Omnirad 127"), solvent (cyclohexanone, methyl isobutyl ketone, propylene glycol monomethyl ether), solid content 35 mass%) to achieve a solid content of 8 mass%.

[0151] <Preparation of Alumina Particles Surface-Treated with a Silane Coupling Agent Having Reactive Groups>

[0152] 25 g of untreated alumina particles (average particle diameter 160 nm), 2.5 g of a silane coupling agent (3-acryloxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Industry "KBM-5103"), and 72.5 g of propylene glycol monomethyl ether were added to a 500 ml stainless steel pot, and the mixture was mixed and dispersed for 30 minutes at 4000 rpm using a homomixer ("Homomixer-MARK II Type 2.5" manufactured by Primix Co., Ltd.) to obtain a dispersion of alumina particles surface-treated with a silane coupling agent having an acryloyl group as a reactive group.

[0153] <Preparation of a composition for forming a low-refractive-index layer>

[0154] A composition for forming a low refractive index layer was prepared by combining a binder resin, hollow silica particles, alumina particles, fluorine-containing (meth)acrylate (only in Example 2 and Comparative Example 2), and a photopolymerization initiator to achieve the composition (mass% of total solid content) listed in Table 1, and by using a solvent (MEK / PGM=1 / 3) to adjust the solid content concentration to that listed in Table 1.

[0155] The materials used as materials for the composition for forming a low refractive index layer are as follows.

[0156] · Binder resin: "Aronix MT-3041" manufactured by Doagosei, polyfunctional acrylate, solid content 100 mass%

[0157] · Hollow silica particles: "Sulyria 4320" manufactured by JGC Catalytic Chemical Industry, average particle diameter 60 nm, solvent: MIBK, solid content 20 mass%

[0158] · Alumina particle 1: The above-mentioned alumina particle dispersion 1

[0159] · Alumina Particles 2: Alumina sol "Lioduras KT-110AL" manufactured by Toyo Kemmu; alumina particles (average particle diameter: 110 nm, no surface treatment) 25 mass%, photosensitive monomer and resin 15 mass%, solvent (MEK, cyclohexanone, aliphatic solvent)

[0160] · Fluorine-containing (meth)acrylate: Manufactured by Shin-Etsu Chemical "KY-1216"; Perfluoropolyether group-containing (meth)acrylate, methyl ethyl ketone; Solid content 20 mass%

[0161] · Photopolymerization initiator: The above "Omnirad 127"

[0162] <Preparation of a composition for forming an antifouling layer>

[0163] A composition for forming an antifouling layer was prepared by combining a fluorine-containing compound (the "KY-1216") and a photopolymerization initiator (the "Omnirad 127") to achieve the composition (mass% of total solid content) listed in Table 1, and by using a solvent (MEK / PGM=1 / 3) to adjust the solid content concentration to the level listed in Table 1.

[0164] <Manufacturing of Hard Coating Layer>

[0165] For each of Examples 1 and 2 and Comparative Examples 1 to 3, a composition for forming a hard coat layer was applied to a substrate film (Toray "Lumirror #50-U403", polyethylene terephthalate film, thickness 50 μm) using a #12 wire bar, dried at 80°C for 60 seconds, and then irradiated with ultraviolet light of 200 mJ / cm² using a high-pressure mercury lamp to form a hard coating layer (film thickness: 4 μm).

[0166] <Manufacturing of High Refractive Index Layer>

[0167] For each of Examples 1 and 2 and Comparative Examples 1 to 3, a composition for forming a high refractive index layer was applied to the surface of a hard coating layer, dried at 80°C for 60 seconds, and then irradiated with ultraviolet light of 200 mJ / cm² using a high-pressure mercury lamp under a nitrogen atmosphere to form a high refractive index layer (film thickness: 110 nm).

[0168] <Manufacturing of Low Refractive Index Layer>

[0169] For each of Examples 1 and 2 and Comparative Examples 1 to 3, a composition for forming a low refractive index layer was applied to the surface of a high refractive index layer using a #3 wire bar, dried at 100°C for 60 seconds, and then a low refractive index layer was formed by irradiating ultraviolet light with a light intensity of 200 mJ / cm² using a high-pressure mercury lamp under a nitrogen atmosphere. The film thickness was as shown in Table 1.

[0170] <Manufacturing of Antifouling Layer>

[0171] For Example 1 and Comparative Example 1, a composition for forming an antifouling layer was applied to the surface of the low refractive index layer using a #3 wire bar, dried at 100°C for 60 seconds, and then an antifouling layer was formed by irradiating ultraviolet light with a light intensity of 200 mJ / cm² using a high-pressure mercury lamp under a nitrogen atmosphere. The film thickness was as shown in Table 1. For Example 2 and Comparative Examples 2 and 3, no antifouling layer was formed.

[0172] Above, anti-reflective films according to Examples 1 and 2 and Comparative Examples 1 to 3 were prepared.

[0173] <Evaluation Method>

[0174] (Thickness and refractive index of each layer)

[0175] For each sample, the thickness and refractive index of the hard coating layer, high refractive index layer, low refractive index layer, and antifouling layer were evaluated. At this time, for each layer, the thickness of each layer and the refractive index at a wavelength of 589.3 nm were calculated by curve fitting using the least squares method between the reflection spectroscopic spectrum in the wavelength range of 380 to 780 nm obtained using a microscopic film thickness measuring instrument (Otsuka Electronics "OPTM-F1") and the theoretical spectrum derived based on Fresnel's equation.

[0176] (Visual reflectance)

[0177] The back side (the side opposite to the low refractive index layer) of the manufactured anti-reflective film was roughened with #400 sandpaper and completely coated with black paint. Then, the 5° specular reflectance of the anti-reflective film surface was measured at wavelengths of 380 to 780 nm using an ultraviolet-visible-near-infrared spectrophotometer ("UV-3600" manufactured by Shimadzu Corporation), and the luminous reflectance was calculated by multiplying this measured value by the relative luminous sensitivity value. If the luminous reflectance is 2.0% or less, the anti-reflective performance is considered sufficient.

[0178] (Hand contact sensation)

[0179] The water contact angle was measured on the surface of the manufactured anti-reflective film. For the measurement, a contact angle meter (Kyowa Interface Science, DropMaster DMo-502) was used, and 4 μL of pure water was dropped onto the surface of the sample (the surface of the antifouling layer for Example 1 and Comparative Example 1, and the surface of the low refractive index layer for Example 2 and Comparative Examples 2 and 3) to measure the water contact angle. If the water contact angle is 100° or greater, it can be considered sufficiently large from the perspective of antifouling performance.

[0180] (Wear resistance)

[0181] For each sample, wear durability was evaluated using an eraser wear test with water contact angle as an indicator.

[0182] For each sample, an eraser wear test was performed. At this time, a flat wear tester (manufactured by Daiei Kagaku Seiki Jakusaku "DAS-400") was used to place an eraser for the wear test (manufactured by Minoan, a cylindrical contact surface with a diameter of φ 6 mm) on the surface of the anti-reflective film of each sample and reciprocate it. The stroke length of the test stand was set to 50 mm, the reciprocating speed of the test stand to 30 reciprocatings / min, and the applied load was set to 1.0 kg. The water contact angle was measured every 100 reciprocatings up to 500 reciprocatings, and every 500 reciprocatings thereafter after exceeding 500 reciprocatings. The maximum number of reciprocatings maintaining a water contact angle of 90° or more was set as the evaluation value. If the evaluation value is 2,000 or more, it can be considered to have sufficient wear durability. Furthermore, if the evaluation value is 4,000 or more, it can be considered to have high wear durability. The water contact angle was measured by dropping 4 μL of pure water onto the surface of an anti-reflective film using a contact angle meter (Kyowa Interface Science, DropMaster DMo-502).

[0183] (Content)

[0184] For each sample, an eraser abrasion test was performed in the presence of ethanol, and solvent resistance was evaluated using the water contact angle as an indicator.

[0185] An eraser abrasion test was performed on each sample. Using a flat abrasion tester (manufactured by DA Science & Precision Machinery Co., Ltd. "DAS-400"), an eraser for the abrasion test (manufactured by Minoan, with a contact surface diameter of φ 6 mm, cylindrical) was placed on the surface of the anti-reflective film of each sample and reciprocated 1,500 times. The stroke length of the test stand was set to 50 mm, the reciprocating speed to 30 reciprocatings / min, and the applied load to 1.0 kg. At this time, 200 μL of ethanol was dropped onto the contact area of ​​the eraser of each sample using a micropipette before the test began and every 200 reciprocatings. After 1,500 reciprocatings, the contact angle was measured; if it dropped to less than 90°, it was evaluated as low solvent resistance (×). Conversely, if a water contact angle of 90° or more was maintained, it was evaluated as high solvent resistance (○). In addition, if a water contact angle of 90° or more is maintained and there are no signs of wear (changes in reflective properties at the friction part), the solvent resistance is evaluated as particularly excellent (◎).

[0186] (Abrasion resistance)

[0187] For each sample, a steel wool test was performed. Using a flat abrasion tester (Daiei Kagaku Seiki Jakushu, "DAS-400"), steel wool #0000 (manufactured by Japan Steel Wool Co., Ltd.), fixed to a flat friction plate measuring 20 mm × 20 mm, was placed on the surface of the anti-reflective film of each sample and reciprocated. The test table was set to a stroke length of 50 mm, a reciprocating speed of 60 reciprocatings / min, and an applied load of 1.5 kg, and reciprocated 100 times. After the test, scratches of 10 mm or more in length on the anti-reflective film were evaluated as having low scratch resistance (×). Additionally, scratches of less than 10 mm in length but no scratches of 10 mm or more in length were evaluated as having high scratch resistance (○). Scratches of this magnitude do not pose a practical problem. Furthermore, scratches without any scratches were evaluated as having very high scratch resistance (◎).

[0188] <Evaluation Results>

[0189] Table 1 shows the evaluation results for Examples 1 and 2 and Comparative Examples 1 to 3, along with the component composition of the low refractive index layer and the antifouling layer (unit: mass% of the total solid content of each layer) and the layer composition of the anti-reflective film.

[0190] Examples Comparative example 1 2 1 2 3 Composition (mass%) of the low-refractive-index layer Binder resin 55 47 55 47 55 hollow silica particles 36 36 36 36 36 Alumina particle 1 4 4 - - 4 Alumina particles 2 - - 4 4 - Fluorine-containing (meth)acrylates - 8 - 8 - Polymerization initiator 5 5 5 5 5 Solid content concentration (%) 3 3 3 3 3 Composition of the antifouling layer (mass%) Fluorine-containing (meth)acrylates 93 - 93 - - Polymerization initiator 7 - 7 - - Solid content concentration (%) 0.35 - 0.35 - - Layer composition base film Thickness (㎛) 50 50 50 50 50 hard coating layer Refractive index 1.52 1.52 1.52 1.52 1.52 Thickness (㎛) 4.0 4.0 4.0 4.0 4.0 High refractive index layer Refractive index 1.68 1.68 1.68 1.68 1.68 Thickness (nm) 110 110 110 110 110 low refractive index layer Refractive index 1.43 1.43 1.43 1.43 1.43 Thickness (nm) 85 92 85 90 85 Antifouling layer Refractive index 1.45 - 1.45 - - Thickness (nm) 5 - 5 - - evaluation Water contact angle (°) 110.6 110.9 110.7 111.1 53.1 Wear resistance 7000 4000 200 100 <100 Content ◎ ○ × × × Internal scratch resistance ◎ ◎ ○ ○ × Visual reflectance (%) 0.8 0.8 0.8 0.8 0.8

[0191] As shown in Table 1, in Examples 1 and 2, the water contact angle of the anti-reflective film surface was 100° or greater, demonstrating that the anti-reflective film has high antifouling properties. In addition, both Examples 1 and 2 obtained high wear durability with an evaluation value of over 2,000 cycles and high solvent resistance rated as "◎" or "○". At the same time, they possess high scratch resistance rated as "◎". This is thought to be because the composition constituting the low refractive index layer includes alumina particles surface-treated with a silane coupling agent capable of forming a bond with the (meth)acrylate compound, in addition to hollow silica particles and a (meth)acrylate compound having reactive groups.

[0192] In particular, in Example 1, particularly high solvent resistance rated as “◎” was obtained by having an antifouling layer made of a cured product of a composition containing fluorine-containing (meth)acrylate on the surface of a low refractive index layer.

[0193] Meanwhile, Comparative Examples 1 and 2 differ from Examples 1 and 2, respectively, in that the alumina particles contained in the low refractive index layer were not surface-treated with a silane coupling agent having reactive groups capable of forming bonds with (meth)acrylate compounds. Accordingly, wear resistance and solvent resistance were reduced. Scratch resistance was also reduced compared to Examples 1 and 2.

[0194] In Comparative Example 3, the water contact angle of the anti-reflective film surface is less than 100°, indicating that the antifouling properties of the anti-reflective film are low. Abrasion resistance, solvent resistance, and scratch resistance are also insufficient.

[0195] As shown above, the anti-reflective film comprises a base film, a hard coating layer formed on the surface of the base film, and a low refractive index layer formed on the surface of the hard coating layer, or additionally, an antifouling layer formed on the surface of the low refractive index layer. The low refractive index layer is composed of a cured product of an ionizing radiation-curable composition containing a (meth)acrylate compound having reactive groups, hollow silica particles, and alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming a bond with the (meth)acrylate compound. By having a water contact angle of 100° or more on the surface of the anti-reflective film, the anti-reflective film possesses excellent antifouling and scratch resistance, as well as high wear resistance and solvent resistance. It can withstand rubbing with a cloth or finger soaked in a solvent such as alcohol.

[0196] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible within the scope of the invention without departing from its spirit. Explanation of the symbols

[0197] 10, 20, 30, 40, 50: Anti-reflective film 12: Substrate film 14: Hard coating layer 15: High refractive index layer 16: Low refractive index layer 18: Antifouling layer 22: Transparent adhesive layer 24: Release film 26: Adhesive layer 28: Protective film

Claims

Claim 1 Base film; a hard coating layer formed on the surface of the base film; An anti-reflective film having a low-refractive-index layer formed on the surface of the hard coating layer, wherein the low-refractive-index layer is composed of a cured product of an ionizing radiation-curable composition comprising a (meth)acrylate compound having reactive groups, hollow silica particles, and alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming a bond with the (meth)acrylate compound; wherein the difference (rd) between the average particle diameter (r) of the alumina particles and the thickness (d) of the low-refractive-index layer is 10 nm or more; the content of the alumina particles in the low-refractive-index layer is 2.0 mass% or more and 6.0 mass% or less with respect to 100 mass% of the solid content of the low-refractive-index layer; the content of the silane coupling agent in the low-refractive-index layer is in the range of 1 mass part or more and 50 mass parts or less with respect to 100 mass parts of the alumina particles; and the surface water contact angle of the anti-reflective film is 100° or more. Anti-reflective film. Claim 2 An anti-reflective film according to claim 1, characterized in that the ionizing radiation-curable composition constituting the low refractive index layer additionally contains a fluorine-containing (meth)acrylate. Claim 3 A base film; a hard coating layer formed on the surface of the base film; a low refractive index layer formed on the surface of the hard coating layer; An anti-reflective film having an antifouling layer formed on the surface of the low-refractive-index layer; wherein the low-refractive-index layer is composed of a cured product of an ionizing radiation-curable composition comprising a (meth)acrylate compound having reactive groups, hollow silica particles, and alumina particles surface-treated with a silane coupling agent having reactive groups capable of forming a bond with the (meth)acrylate compound, and the antifouling layer is composed of a cured product of an ionizing radiation-curable composition comprising a fluorine-containing (meth)acrylate, wherein the difference (rd) between the average particle diameter (r) of the alumina particles and the thickness (d) of the low-refractive-index layer is 10 nm or more, the content of the alumina particles in the low-refractive-index layer is 2.0 mass% or more and 6.0 mass% or less with respect to 100 mass% of the solid content of the low-refractive-index layer, and the content of the silane coupling agent in the low-refractive-index layer is 1 with respect to 100 mass parts of the alumina particles An anti-reflective film having a mass part or more and a mass part or less of 50 parts, and a surface water contact angle of the anti-reflective film of 100° or more. Claim 4 An anti-reflective film according to claim 3, characterized in that the content of the fluorine-containing (meth)acrylate in the antifouling layer is 90 mass% or more based on the total solid content of the antifouling layer. Claim 5 An anti-reflective film according to claim 3 or 4, characterized in that the low refractive index layer does not contain a fluorine-containing compound.

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