Antireflection film

Abstract

To provide an antireflection film that can impart high antifouling properties without relying on fluorine-containing compounds, while also having high antireflection properties and excellent scratch resistance and wear resistance.SOLUTION: An antireflection film 10 includes a base film 12, a hard coat layer 14 formed on a surface of the base film 12, and a low-refractive-index layer 16 formed on a surface of the hard coat layer 14, wherein the low-refractive-index layer 16 is formed of a cured product of an ionizing-radiation-curable composition containing a polyfunctional (meth)acrylate compound having a reactive group and a monofunctional (meth)acrylate compound having a linear alkyl group having 16 or more carbon atoms.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an antireflection film, and more particularly to an antireflection film suitable for use on the surfaces of displays such as liquid crystal displays, organic EL displays, and touch panels for smartphones and the like. [Background technology]

[0002] Anti-reflection films are often applied to the surfaces of displays such as liquid crystal displays, organic electroluminescence (EL) displays, and touch panels of smartphones and the like to prevent external light from being reflected on the screen. Known anti-reflection films include those having a hard coat layer and an optically functional layer, such as a low refractive index layer, in that order on a substrate film. Properties required of anti-reflection films include optical properties such as low reflectance and high transmittance, and physical properties such as abrasion resistance, scratch resistance, and stain resistance. Anti-reflection films with stain resistance have been disclosed, for example, in one having a high refractive index layer and a low refractive index layer on a substrate film, with the low refractive index layer containing a fluorine-containing compound (Patent Document 1), one containing an anti-fouling layer made of a fluorine-containing compound on the surface of the low refractive index layer (Patent Document 2), and one containing a silicone compound in the low refractive index layer (Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-148805 [Patent Document 2] Patent Publication No. 2021-152654 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-154177 Summary of the Invention [Problem to be solved by the invention]

[0004] Although the fluorine-containing compounds used in Patent Documents 1 and 2 are effective in improving antifouling properties, some compounds belonging to the group of perfluoroalkyl and polyfluoroalkyl compounds (PFAS) are restricted substances under the European REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) regulation due to concerns about environmental impact and health hazards, and these restrictions are expected to become stricter in the future. Currently, the main targets of restrictions are fluorine-containing compounds with long-chain perfluoroalkyl groups, such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). Given this background, it is desirable to avoid the use of not only these compounds with long-chain perfluoroalkyl groups, but also all fluorine-containing compounds with fluoroalkyl groups in materials used in displays. The anti-reflection film of Patent Document 3 uses a silicone compound as an antifouling agent and does not contain a fluorine-containing compound, but it is difficult to effectively improve scratch resistance simply by adding a silicone compound as an antifouling agent.

[0005] The problem to be solved by the present invention is to provide an antireflection film that has high antireflection properties as well as excellent scratch resistance and abrasion resistance, and can also be imparted with high antifouling properties without relying on a fluorine-containing compound. [Means for solving the problem]

[0006] In order to solve the above problems, the anti-reflection film according to the present invention has the following configuration. [1] The antireflection film according to the present invention comprises a substrate film, a hard coat layer formed on the surface of the substrate film, and a low refractive index layer formed on the surface of the hard coat layer, wherein the low refractive index layer is formed from a cured product of an ionizing radiation-curable composition containing a polyfunctional (meth)acrylate compound having a reactive group and a monofunctional (meth)acrylate compound having an alkyl group with a linear structure and having 16 or more carbon atoms.

[0007] [2] In the above aspect [1], the low refractive index layer may not contain a fluorine-containing compound having a fluoroalkyl group.

[0008] [3] In the above aspect [1] or [2], the antireflection film may include a high refractive index layer and the low refractive index layer in this order on the surface of the hard coat layer, and the refractive index of the high refractive index layer at a wavelength of 550 nm may be higher than the refractive index of the hard coat layer and higher than the refractive index of the low refractive index layer.

[0009] [4] In any one of the above aspects [1] to [3], the low refractive index layer may further contain alumina particles that have been surface-treated with a silane coupling agent having a reactive group capable of forming a bond with the polyfunctional (meth)acrylate compound.

[0010] [5] In any one of the above aspects [1] to [4], the low refractive index layer may further contain hollow silica particles that have been surface-treated with a silane coupling agent having a reactive group capable of forming a bond with the polyfunctional (meth)acrylate compound.

[0011] In any one of the above aspects [1] to [5], the low refractive index layer may further contain a silicone compound having a reactive group capable of forming a bond with the polyfunctional (meth)acrylate compound. [Effects of the Invention]

[0012] The antireflection film according to the present invention comprises a substrate film, a hard coat layer formed on the surface of the substrate film, and a low refractive index layer formed on the surface of the hard coat layer. The low refractive index layer is formed from a cured product of an ionizing radiation-curable composition that contains a polyfunctional (meth)acrylate compound having a reactive group, hollow silica particles, and a monofunctional (meth)acrylate compound having an alkyl group with a linear structure and having 16 or more carbon atoms. Therefore, the antireflection film has high antireflection properties, as well as excellent scratch resistance and abrasion resistance, and can impart high antifouling properties without relying on fluorine-containing compounds. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view of an antireflection film according to a first embodiment of the present invention. [Figure 2] FIG. 3 is a cross-sectional view of an antireflection film according to a second embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view of an antireflection film according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a cross-sectional view of an anti-reflection film according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will be described in detail below. In this specification, various physical properties refer to values ​​at room temperature in the atmosphere unless otherwise specified. Furthermore, in this specification, the refractive index of a substance and a substance layer refers to the refractive index at a measurement wavelength of 550 nm unless otherwise specified.

[0015] <Anti-reflection film of first embodiment> Fig. 1 is a cross-sectional view of an antireflection film according to a first embodiment of the present invention. As shown in Fig. 1, an antireflection film 10 according to the first embodiment of the present invention comprises a substrate film 12, a hard coat layer 14 formed on the surface of the substrate film 12, and a low refractive index layer 16 formed on the surface of the hard coat layer 14. In this embodiment, the above layers are laminated in order without any other layers interposed therebetween. The low refractive index layer 16 is the layer exposed on the outermost surface of the entire antireflection film 10.

[0016] (Base film) The substrate film 12 is not particularly limited as long as it is transparent. Examples of the substrate film 12 include transparent polymer films and glass films. Transparency refers to a total light transmittance of 50% or more in the visible light wavelength range, and the total light transmittance is more preferably 85% or more. The total light transmittance can be measured in accordance with JIS K7361-1 (1997). The thickness of the substrate film 12 is not particularly limited, but from the viewpoint of excellent handleability, it is preferably in the range of 2 μm to 500 μm, and more preferably in the range of 2 μm to 200 μm. Note that the term "film" generally refers to a film having a thickness of less than 0.25 mm, but even if the thickness is 0.25 mm or more, it is considered to be a "film" if it can be wound into a roll.

[0017] Examples of polymeric materials for the base film 12 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, and other polyolefin resins, cellulose-based resins such as triacetyl cellulose resin and diacetyl cellulose resin, polyphenylene sulfide resin, polyvinyl chloride resin, polyvinylidene chloride resin, and polyvinyl alcohol resin. The polymeric material for the base film 12 may be composed of only one of these materials or a combination of two or more. 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 from the viewpoints of optical properties and durability.

[0018] The base film 12 may be composed of a single layer containing one or more of the above polymeric materials, or may be composed of two or more layers, such as a layer containing one or more of the above polymeric materials and a layer containing one or more of a different polymeric material.

[0019] (Hard coat layer) The hard coat layer 14 contributes to improving the scratch resistance of the anti-reflection film 10. The hard coat 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 an energy quantum capable of polymerizing or crosslinking molecules. Examples of ionizing radiation include electromagnetic waves such as ultraviolet (UV) rays, X-rays, and gamma rays, and charged particle beams such as electron beams (EB), alpha rays, and ion beams. Of these, ultraviolet (UV) rays are particularly preferred from the viewpoint of productivity. Hereinafter, the ionizing radiation-curable composition may be simply referred to as a curable composition. In this specification, "(meth)acrylate" refers to "at least one of acrylate and methacrylate." "(meth)acryloyl" refers to "at least one of acryloyl and methacryloyl." "(meth)acrylic" refers to "at least one of acrylic and methacrylic." The "(meth)acrylate compound" is a compound having a (meth)acryloyl group, and examples thereof include a monomer, an oligomer, a prepolymer, etc. Hereinafter, the (meth)acrylate compound may be simply referred to as a (meth)acrylate.

[0020] The (meth)acrylate may be a monofunctional (meth)acrylate or a polyfunctional (meth)acrylate. Alternatively, the (meth)acrylate may be a combination of a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate. From the viewpoint of improving curability, it is more preferable that the curable composition contains a polyfunctional (meth)acrylate as the (meth)acrylate.

[0021] Examples of (meth)acrylates include urethane (meth)acrylate, silicone (meth)acrylate, alkyl (meth)acrylate, and aryl (meth)acrylate. Among these, urethane (meth)acrylate, particularly urethane (meth)acrylate oligomer, is preferred. Specific examples of urethane (meth)acrylates include those obtained by reacting a polyisocyanate compound with a hydroxyl group-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 nurate-modified, adduct-modified, and biuret-modified versions of these compounds. 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 polyoxyalkylene-modified and polylactone-modified versions thereof. Examples of polyol compounds include ethylene glycol, propylene glycol, butanediol, hexanediol, polyoxyethylene glycol, polyoxypropylene glycol, glycerin, trimethylolpropane, pentaerythritol, biphenol, and bisphenol. When the curable composition for forming the hard coat layer 14 contains a urethane (meth)acrylate as the UV-curable resin, the hard coat layer 14 has appropriate flexibility, thereby improving the flex resistance of the antireflection film 10 and making it suitable for use in flexible displays that are repeatedly bent, such as foldable displays and rollable displays. Furthermore, even if the base film 12 is made of, for example, polycycloolefin or cycloolefin copolymer, which is relatively prone to cracking, cracking of the base film 12 is easily prevented.

[0022] It is preferable that the (meth)acrylate constituting the curable composition further contains a pentaerythritol (meth)acrylate compound. Specific examples of the pentaerythritol (meth)acrylate compound 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 the curable composition contains pentaerythritol tri(meth)acrylate.

[0023] The curable composition forming the hard coat layer 14 may or may not contain a non-UV curable resin in addition to the UV curable resin. The curable composition forming the hard coat layer 14 may also contain a photopolymerization initiator. If necessary, it may also contain additives that can be generally added to curable compositions. Examples of additives include dispersants, leveling agents, antifoaming agents, thixotropic agents, antifouling agents, antibacterial agents, flame retardants, slip agents, antistatic agents, inorganic particles, and resin particles. If necessary, it may also contain a solvent.

[0024] Non-UV curable resins include thermoplastic resins and thermosetting resins. Thermoplastic resins include polyester resins, polyether resins, polyolefin resins, polyamide resins, etc. Thermosetting resins include unsaturated polyester resins, epoxy resins, alkyd resins, phenolic resins, etc.

[0025] Examples of the photopolymerization initiator include alkylphenone-based, acylphosphine oxide-based, and oxime ester-based photopolymerization initiators. Examples of the alkylphenone-based photopolymerization initiator include 2,2'-dimethoxy-1,2-diphenylethan-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, and the like. Examples of the acylphosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Examples of the oxime ester photopolymerization initiator include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime), ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime), etc. These photopolymerization initiators may be used alone or in combination of two or more.

[0026] The content of the photopolymerization initiator is preferably in the range of 0.1% by mass to 10% by mass, more preferably 1% by mass to 5% by mass, based on the total solid content of the curable composition.

[0027] The inorganic particles and resin particles can be added to the hard coat layer 14 for purposes such as preventing blocking of the hard coat layer 14 and adjusting the refractive index of the hard coat layer 14. The inorganic particles or resin particles added form fine surface irregularities on the hard coat layer 14, which makes it easier to prevent blocking, which occurs when the hard coat film made of the base film 12 and the hard coat layer 14 before the low refractive index layer 16 is formed, is wound into a roll.

[0028] Examples of inorganic particles capable of adjusting the refractive index of the hard coat layer 14 include metal oxide particles made of oxides of metals such as titanium, zirconium, tin, zinc, silicon, niobium, aluminum, chromium, magnesium, germanium, gallium, antimony, and platinum. These may be used alone or in combination as optically adjustable inorganic particles. Among these, titanium oxide and zirconium oxide are particularly preferred from the viewpoint of achieving both a high refractive index and excellent transparency. Examples of resin particles include resin particles made 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 alone or in combination as resin particles.

[0029] The thickness of the hard coat layer 14 is not particularly limited, but is preferably 0.5 μm or more from the viewpoint of having sufficient hardness, and more preferably 0.75 μm or more. Furthermore, from the viewpoint of easily suppressing curling due to the difference in thermal shrinkage from the base film 12, it is preferably 20 μm or less, and more preferably 10 μm or less. The thickness of the hard coat layer 14 is the thickness of a relatively smooth portion in the thickness direction that is free from irregularities due to inorganic particles or resin particles.

[0030] The refractive index of the hard coat layer 14 is preferably within the range of 1.49 to 1.56 in order to suppress interference unevenness caused by the difference in refractive index between the substrate film 12 and the hard coat layer 14 . The arithmetic mean roughness Ra of the surface of the hard coat layer 14 on which the surface irregularities are formed is preferably in the range of 0.3 nm to 20 nm, more preferably 0.5 nm to 10 nm, from the viewpoint of suppressing blocking.

[0031] Examples of solvents used in the curable composition for forming the hard coat 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 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 solvents may be used alone or in combination of two or more.

[0032] The solids concentration of the curable composition (concentration of components other than the solvent) can be determined appropriately taking into consideration factors such as coatability and film thickness. For example, it may be 1% by mass to 90% by mass, 1.5% by mass to 80% by mass, or 2% by mass to 70% by mass. Unlike the low refractive index layer 16 described below, the hard coat layer 14 preferably does not contain amino-modified organopolysiloxane or its reaction products. If the hard coat layer 14 contains amino-modified organopolysiloxane or its reaction products, the adhesion of a layer formed on the hard coat layer 14 (here, the low refractive index layer 16) may be impaired.

[0033] (low refractive index layer) In the antireflection film 10 according to this embodiment, a low refractive index layer 16 is provided as an antireflection layer on the surface of the hard coat layer 14. The low refractive index layer 16 has a refractive index lower than that of the hard coat layer 14, and exhibits an antireflection effect due to the difference in refractive index between the low refractive index layer 16 and the hard coat layer 14.

[0034] The low refractive index layer 16 is formed from a cured product of an ionizing radiation-curable composition containing a polyfunctional (meth)acrylate compound having a reactive group and a long-chain alkyl (meth)acrylate, i.e., a (meth)acrylate compound having an alkyl group with a linear structure having 16 or more carbon atoms. As explained above for the hard coat 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. A preferred composition of the composition will be explained below.

[0035] (1) Polyfunctional (meth)acrylate compound having a reactive group Examples of polyfunctional (meth)acrylate compounds having reactive groups include urethane (meth)acrylates, silicone (meth)acrylates, alkyl (meth)acrylates, and aryl (meth)acrylates. The (meth)acrylate compounds may have only (meth)acryloyl groups as reactive groups, or may have other reactive groups in addition to (meth)acryloyl groups. The reactive groups are preferably ionizing radiation-reactive groups, particularly ultraviolet-reactive groups. Examples of ultraviolet-reactive groups other than (meth)acryloyl groups include carbon-carbon unsaturated double bond groups such as vinyl groups, styryl groups, and allyl groups, and ring-opening polymerizable groups such as epoxy groups and oxetanyl groups. A polyfunctional (meth)acrylate compound refers to a compound having multiple reactive groups in one molecule, and preferably has multiple (meth)acryloyl groups.

[0036] 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, trimethylolpropane tri(meth)acrylate, etc. 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.

[0037] The polyfunctional (meth)acrylate compound contained in the curable composition may be composed of one kind alone or two or more kinds, such as the above-mentioned polyfunctional (meth)acrylate. From the viewpoint of improving scratch resistance, the polyfunctional (meth)acrylate compound contained in the curable composition preferably contains a pentafunctional or higher polyfunctional (meth)acrylate, and it is also preferable to increase the content of the pentafunctional or higher polyfunctional (meth)acrylate.

[0038] Furthermore, the polyfunctional (meth)acrylate preferably contains a dimer. Dimers of polyfunctional (meth)acrylates have an excellent curing rate and can easily increase the curing rate of the curable composition, thereby further improving scratch resistance. Among them, it is preferable to contain 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 contain at least one selected from the group consisting of dimers of pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0039] From the viewpoints of scratch resistance, transparency, and solubility in solvents, the content of the dimer is preferably in the range of 25% by mass to 50% by mass, more preferably 30% by mass to 40% by mass, based on the total solid content of the polyfunctional (meth)acrylate.

[0040] (2) Long-chain alkyl (meth)acrylate The long-chain alkyl (meth)acrylate is a (meth)acrylate compound having an alkyl group with a linear structure and 16 or more carbon atoms. The long-chain alkyl (meth)acrylate is monofunctional. That is, it contains only one (meth)acrylate group in the molecule and contains no other ionizing radiation reactive groups. Furthermore, it preferably contains no functional groups other than the ionizing radiation reactive groups. The inclusion of the long-chain alkyl (meth)acrylate in the low refractive index layer 16 imparts high antifouling properties to the antireflection film 10, as well as improving scratch resistance and abrasion resistance.

[0041] In the low refractive index layer 16, the long-chain alkyl (meth)acrylate forms a bond with the polyfunctional (meth)acrylate after being irradiated with ionizing radiation, and together with the polyfunctional (meth)acrylate, forms a polymer. This polymer becomes a side-chain crystalline polymer. The linear alkyl group having 16 or more carbon atoms contained in the long-chain alkyl (meth)acrylate functions as a side-chain crystalline moiety in the side-chain crystalline polymer. That is, the side-chain crystalline polymer is formed as a comb-shaped polymer having a linear alkyl group having 16 or more carbon atoms in its side chain. The side chains are then aligned in an orderly arrangement by intermolecular forces, etc., causing the side-chain crystalline polymer to crystallize. As a result, the low refractive index layer 16 forms a strong film, and the anti-reflection film 10 has excellent scratch resistance and abrasion resistance.

[0042] Examples of long-chain alkyl (meth)acrylates include cetyl (meth)acrylate (C16; the number of carbon atoms in the alkyl group is indicated; the same applies below), heptadecyl (meth)acrylate (C17), stearyl (meth)acrylate (C18), n-nonadecyl (meth)acrylate (C19), n-eicosyl (meth)acrylate (C20), and n-heneicosyl (meth)acrylate (C2 1), n-behenyl (meth)acrylate (C22), n-tricosyl (meth)acrylate (C23), n-tetracosyl (meth)acrylate (C24), n-pentacosyl (meth)acrylate (C25), n-hexacosyl (meth)acrylate (C26), n-heptacosyl (meth)acrylate (C27), n-octacosyl (meth)acrylate (C28), and the like.

[0043] The number of carbon atoms in the linear alkyl group contained in the long-chain alkyl (meth)acrylate is not particularly limited as long as it is 16 or more, but from the viewpoint of particularly effectively enhancing stain resistance, scratch resistance, and abrasion resistance, it is preferably 18 or more, more preferably 20 or more, and even more preferably 22 or more. On the other hand, the upper limit of the carbon number is not particularly limited, but from the viewpoint of compatibility with solvents and manufacturability, it is preferably 24 or less. That is, the long-chain alkyl (meth)acrylate is more preferably at least one selected from stearyl (meth)acrylate, n-nonadecyl (meth)acrylate, n-eicosyl (meth)acrylate, n-heneicosyl (meth)acrylate, n-behenyl (meth)acrylate, n-tricosyl (meth)acrylate, and n-tetracosyl (meth)acrylate.

[0044] The long-chain alkyl (meth)acrylates listed above may be used alone or in combination of two or more. The content of the long-chain alkyl (meth)acrylate in the low refractive index layer 16 is preferably 1% by mass or more and 16% by mass or less, based on 100% by mass of the solid content of the low refractive index layer 16. When the content of the long-chain alkyl (meth)acrylate in the low refractive index layer 16 is 1% by mass, based on 100% by mass of the solid content of the low refractive index layer 16, the antifouling properties of the antireflection film 10 can be effectively improved, and the slipperiness and scratch resistance can be improved. From this viewpoint, the content of the long-chain alkyl (meth)acrylate in the low refractive index layer 16 is more preferably 2% by mass or more, and even more preferably 4% by mass or more, based on 100% by mass of the solid content of the low refractive index layer 16. When the content of the long-chain alkyl (meth)acrylate in the low refractive index layer 16 is 16% by mass or less, based on 100% by mass of the solid content of the low refractive index layer 16, the long-chain alkyl (meth)acrylate is compatible with the polyfunctional (meth)acrylate compound, exhibits sufficient transparency, and can suppress a decrease in scratch resistance. From this viewpoint, the content of the long-chain alkyl (meth)acrylate in the low-refractive index layer 16 is more preferably 14% by mass or less, and even more preferably 12% by mass or less, relative to 100% by mass of the solid content of the low-refractive index layer 16. Although the low-refractive index layer 16 may contain, in addition to the predetermined long-chain alkyl (meth)acrylate, a monofunctional (meth)acrylate compound having an alkyl group with a linear structure having less than 16 carbon atoms or a monofunctional (meth)acrylate compound having an alkyl group with a branched structure, it is preferable to keep the total content of these monofunctional (meth)acrylate compounds other than the predetermined long-chain alkyl (meth)acrylate lower than the content of the predetermined long-chain alkyl (meth)acrylate.

[0045] As described above, the low refractive index layer 16 of the antireflection film 10 according to this embodiment is formed from a cured product of an ionizing radiation-curable composition containing a polyfunctional (meth)acrylate compound having a reactive group and a long-chain alkyl (meth)acrylate, i.e., a (meth)acrylate compound having an alkyl group with a linear structure and 16 or more carbon atoms. The curable composition constituting the low refractive index layer 16 may contain components other than the polyfunctional (meth)acrylate compound and long-chain alkyl (meth)acrylate, as appropriate. Such components include alumina particles, hollow silica particles, silicone compounds, and the "other components" listed below.

[0046] (3) Alumina particles The curable composition constituting the low refractive index layer 16 may further contain alumina particles. In this case, the alumina particles may be surface-treated with a silane coupling agent having a reactive group capable of forming a bond with a polyfunctional (meth)acrylate compound. When the alumina particles are contained in the low refractive index layer 16, they form convex portions on the surface of the low refractive index layer 16. The formation of convex portions on the surface of the low refractive index layer 16 by the alumina particles allows the low refractive index layer 16 to have particularly good scratch resistance.

[0047] The alumina particles may be solid or hollow, but are preferably solid. Solid particles are particles that have substantially no voids inside, with the voids accounting for less than 5% of the total particle volume. Hollow particles are particles that have voids inside, with the voids accounting for 5% or more of the total particle volume. Solid alumina particles improve the scratch resistance of the low refractive index layer 16 and the scratch resistance of the anti-reflection film 10. Hollow alumina particles can lower the refractive index of the low refractive index layer 16 and reduce light reflection. The void ratio in hollow particles is preferably 10% to 80% of the total particle volume. A void ratio of 10% or more can lower the refractive index and reduce light reflection. A void ratio of 20% or more is more preferable, and a void ratio of 30% or more is even more preferable. A void ratio of 80% or less can prevent a decrease in the dispersibility of the alumina particles. More preferably, it is 60% or less.

[0048] The shape of the alumina particles is not particularly limited, and may be spherical, needle-like, scale-like, rod-like, fibrous, amorphous, etc. Of these, spherical shapes are preferred.

[0049] As described above, the alumina particles may be surface-treated with a silane coupling agent having a reactive group capable of forming a bond with a polyfunctional (meth)acrylate compound contained in the curable composition. When the silane coupling agent has a reactive group capable of forming a bond with a polyfunctional (meth)acrylate compound, the alumina particles surface-treated with the silane coupling agent bond strongly with the polyfunctional (meth)acrylate contained in the low refractive index layer 16 and further bond with reactive groups contained in adjacent layers such as the hard coat layer 14. The formation of these bonds improves the scratch resistance of the anti-reflection film 10.

[0050] Silane coupling agents generally have a hydrolyzable group and other functional groups bonded to silicon atoms in their molecules. Here, the term "hydrolyzable group" refers to a substituent directly bonded to a silicon atom that 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. When the hydrolyzable group has carbon atoms, the number of carbon atoms is preferably 6 or less, and more preferably 4 or less. In particular, alkoxy groups with 4 or less carbon atoms or alkenyloxy groups with 4 or less carbon atoms are preferred. The hydrolyzable group undergoes hydrolysis to form a bond with oxygen atoms on the surface of the alumina particles, thereby surface-treating the alumina particles.

[0051] The silane coupling agent used here contains, in addition to the hydrolyzable group, a reactive group capable of forming a bond with a polyfunctional (meth)acrylate compound. Examples of the reactive group include carbon-carbon unsaturated double bond groups such as (meth)acryloyl, vinyl, styryl, and allyl groups, and ring-opening polymerizable groups such as epoxy and oxetanyl groups. These reactive groups are reactive to ultraviolet light. In the low refractive index layer 16, the reactive group of the polyfunctional (meth)acrylate compound reacts with the reactive group of the silane coupling agent to form a bond.

[0052] Examples of silane coupling agents having a carbon-carbon unsaturated double bond group as a reactive group include p-styryltrimethoxysilane, 2-(allyloxymethyl)acrylate (trimethoxysilyl)propyl, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, p-styryltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and 7-octenyltrimethoxysilane.

[0053] 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, and 8-glycidoxyoctyltrimethoxysilane.

[0054] Among these, from the viewpoint of reactivity with the (meth)acrylate compound, it is preferable to use a silane coupling agent having a carbon-carbon unsaturated double bond group, and among these, a silane coupling agent having an ethylenic carbon-carbon double bond group such as a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group is particularly preferable.

[0055] 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. This enhances the effect of the surface treatment using the silane coupling agent. Furthermore, the scratch resistance of the low refractive index layer 16 can be maintained at a high level, and the abrasion resistance and solvent resistance can be improved. More preferably, the content is 10 parts by mass or more and 40 parts by mass or less. Silane coupling agent that is not bonded to the alumina particles may remain in the low refractive index layer 16, and the preferred content range described herein refers to the total content of the silane coupling agent, including the silane coupling agent that is not bonded to the alumina particles.

[0056] The alumina particles form convex portions on the surface of the low refractive index layer 16, and in order to 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. On the other hand, from the viewpoint of suppressing the height of the formed convex portions to maintain transparency, the difference (rd) is 300 nm or less. More preferably, it is 200 nm or less, and even more preferably 100 nm or less.

[0057] The average particle diameter r of the alumina particles, although depending on the thickness d of the low refractive index layer 16, is preferably in the range of 60 nm to 400 nm. It is more preferably 70 nm or more, and even more preferably 90 nm or more. It is more preferably 300 nm or less, and even more preferably 200 nm or less. The average particle diameter r of the alumina particles is a volume-based average arithmetic value obtained by a laser diffraction / scattering method in accordance with JIS Z8825, and includes not only the primary particle diameter but also the secondary particle diameter, which is a particle aggregate.

[0058] The content of alumina particles in the low refractive index layer 16 is preferably 0.1% by mass or more and 6.0% by mass or less, relative to 100% by mass of the solid content of the low refractive index layer 16. When the content of alumina particles in the low refractive index layer 16 is 0.1% by mass or more, relative to 100% by mass of the solid content of the low refractive index layer 16, excellent scratch resistance can be obtained. From this viewpoint, the content of alumina particles in the low refractive index layer 16 is more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more, relative to 100% by mass of the solid content of the low refractive index layer 16. When the content of alumina particles in the low refractive index layer 16 is 6.0% by mass or less, relative to 100% by mass of the solid content of the low refractive index layer 16, high transparency can be obtained. From this viewpoint, the content of alumina particles in the low refractive index layer 16 is more preferably 5.5% by mass or less, and even more preferably 5.0% by mass or less, relative to 100% by mass of the solid content of the low refractive index layer 16.

[0059] (4) Hollow silica particles The hollow silica particles are silica particles with an average particle diameter smaller than the average thickness d of the low refractive index layer 16. The hollow silica particles preferably have an average particle diameter smaller than the alumina particles that form the protrusions on the surface of the low refractive index layer 16. The hollow silica particles do not substantially contribute to the formation of the surface irregularities of the low refractive index layer 16. The hollow silica particles are particles with internal cavities, with the cavities accounting for 5% or more of their volume. Hollow refers to particles with a shell structure consisting of an outer shell and an internal cavity, or particles with a porous structure containing multiple cavities. The hollow structure of the hollow silica particles can lower the refractive index of the low refractive index layer 16 and reduce light reflection. The shape of the hollow silica particles is not particularly limited, but spherical, spindle-shaped, oval, tabular, cubic, and amorphous shapes are preferred. Of these, spherical, tabular, and cubic shapes are particularly preferred.

[0060] In the hollow silica particles, the proportion of voids is preferably 10% or more and 80% or less by volume. When the proportion of voids is 10% or more by volume, the refractive index can be lowered and light reflection can be reduced. It is more preferably 20% or more by volume, and even more preferably 30% or more by volume. On the other hand, when the proportion of voids is 80% or less by volume, a decrease in the dispersibility of the hollow silica particles can be suppressed. It is more preferably 60% or less by volume.

[0061] The average particle diameter of the hollow silica particles, although depending on the thickness d of the low refractive index layer 16, is preferably 5 nm or more and 100 nm or less. It is more preferably 20 nm or more, and even more preferably 40 nm or more. It is also more preferably 80 nm or less, and even more preferably 70 nm or less. When the average particle diameter of the hollow silica particles is within these preferred ranges, excellent anti-reflection effect and transparency can be obtained in the low refractive index layer 16. The average particle diameter is a volume-based average arithmetic value obtained by a laser diffraction / scattering method in accordance with JIS Z8825. The particle diameter includes not only the primary particle diameter but also the secondary particle diameter, which is a particle aggregate.

[0062] The refractive index of the hollow silica particles is preferably in the range of 1.01 to 1.45, more preferably in the range of 1.15 to 1.38, and even more preferably in the range of 1.15 to 1.35. When the refractive index of the hollow silica particles is in this range, excellent antireflection effects can be obtained.

[0063] The content of hollow silica particles in the low refractive index layer 16 is preferably 6.0% by mass or more and 49.9% by mass or less, based on 100% by mass of the solid content of the low refractive index layer 16. When the content of hollow silica particles in the low refractive index layer 16 is 6.0% by mass, based on 100% by mass of the solid content of the low refractive index layer 16, excellent antireflection properties can be obtained. From this viewpoint, the content of hollow silica particles in the low refractive index layer 16 is more preferably 10% by mass or more, even more preferably 20% by mass or more, and particularly preferably 30% by mass or more, based on 100% by mass of the solid content of the low refractive index layer 16. When the content of hollow silica particles in the low refractive index layer 16 is 49.9% by mass or less, based on 100% by mass of the solid content of the low refractive index layer 16, deterioration in scratch resistance can be suppressed. From this viewpoint, the content of hollow silica particles in the low refractive index layer 16 is more preferably 45% by mass or less, even more preferably 40% by mass or less, based on 100% by mass of the solid content of the low refractive index layer 16.

[0064] The hollow silica particles are preferably surface-treated with a silane coupling agent having a reactive group capable of forming a bond with a polyfunctional (meth)acrylate compound. Since the silane coupling agent has a reactive group capable of forming a bond with a polyfunctional (meth)acrylate compound, the hollow silica particles surface-treated with the silane coupling agent can bond strongly with the (meth)acrylate contained in the low refractive index layer 16 and further bond with reactive groups contained in adjacent layers such as the hard coat layer 14. The formation of these bonds improves the scratch resistance of the anti-reflection film 10. The silane coupling agent can be similar to that used for the surface treatment of the alumina particles.

[0065] The total amount of alumina particles and hollow silica particles in the low refractive index layer 16 is preferably 0.1% by mass or more and 50% by mass or less, relative to 100% by mass of the solid content of the low refractive index layer 16. When the total amount of alumina particles and hollow silica particles in the low refractive index layer 16 is 0.1% by mass or more, relative to 100% by mass of the solid content of the low refractive index layer 16, excellent scratch resistance can be obtained. From this viewpoint, the total amount of alumina particles and hollow silica particles in the low refractive index layer 16 is more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more, relative to 100% by mass of the solid content of the low refractive index layer 16. On the other hand, when the total amount of alumina particles and hollow silica particles in the low refractive index layer 16 is 50% by mass or less, relative to 100% by mass of the solid content of the low refractive index layer 16, the alumina particles and hollow silica particles can be sufficiently retained in the low refractive index layer 16, thereby obtaining excellent scratch resistance. From this viewpoint, the total amount of alumina particles and hollow silica particles in the low refractive index layer 16 is more preferably 45% by mass or less, and even more preferably 40% by mass or less, relative to 100% by mass of the solid content of the low refractive index layer 16.

[0066] (5) Silicone compounds The composition for forming the low refractive index layer 16 may contain a silicone compound to improve the slipperiness and antifouling properties of the surface of the low refractive index layer 16. The silicone compound may or may not have a reactive group, but from the viewpoint of improving scratch resistance, it preferably has a reactive group. Furthermore, it is preferable that the reactive group be capable of forming a bond with a polyfunctional (meth)acrylate compound contained in the composition.

[0067] Examples of silicone compounds having reactive groups include polydimethylsiloxanes having (meth)acrylic groups in the side chain or at one or both ends. Examples of such compounds include "X-22-164," "X-22-164AS," "X-22-164A," "X-22-164B," "X-22-164C," "X-22-164E," "X-22-2445," "X-22-174ASX," "X-22-174BX," "KF-2012," "X-22-2426," and "X-22-2404" manufactured by Shin-Etsu Chemical Co., Ltd., and "TEGO Rad2100," "TEGO Rad2200N," "TEGO Rad2250," "TEGO Rad2300," "TEGO Rad2500," "TEGO Rad2700," and "TEGO Rad2800" manufactured by Evonik. Rad2800'', BYK Chemie's ``BYK-UV3500'', ``BYK-UV3505'', ``BYK-UV3510'', ``BYK-UV3511'', ``BYK-UV3518'', ``BYK-UV351'' 9” “BYK-UV3530” “BYK-UV3535” “BYK-UV3570” “BYK-UV3575” “BYK-UV3576” “BYK-UV3590” “BYK-UV3595” Examples include JNC's "Silaplane FM-0711," "Silaplane FM-0721," "Silaplane FM-0725," "Silaplane FM-7711," "Silaplane FM-7721," and "Silaplane FM-7725," Daicel-Allnex's "EBECRYL350," "EBECRYL1360," "EBECRYL1365," and "KRM8479," and MIWON's "Miramer SIU100" and "Miramer SIU2400."

[0068] (6) Other ingredients The composition for forming the low refractive index layer 16 preferably contains a photopolymerization initiator when the (meth)acrylate compound contains one having a UV-reactive group (when the composition is a UV-curable resin). Furthermore, the composition for forming the low refractive index layer 16 may contain a solvent, if necessary.

[0069] The binder resin of the low refractive index layer 16 may be composed of only a polyfunctional (meth)acrylate compound having a reactive group and a long-chain alkyl (meth)acrylate, or may further comprise only a silicone compound, or may contain other UV-curable resins such as other types of (meth)acrylic resins, or may be composed of a combination of a UV-curable resin and a non-UV-curable resin. The chemical species listed above as specific examples of those that can be contained in the composition for forming the hard coat layer 14 can also be suitably used in the composition for forming the low refractive index layer 16 as the non-UV-curable resin, photopolymerization initiator, and solvent.

[0070] The content of the photopolymerization initiator is preferably in the range of 0.1% by mass to 10% by mass, based on the total solid content of the composition for forming the low refractive index layer 16. More preferably, it is in the range of 1% by mass to 5% by mass.

[0071] The low refractive index layer 16 may also contain additives, if necessary. Examples of such additives include dispersants, leveling agents, antifoaming agents, thixotropic agents, antibacterial agents, flame retardants, slip agents, refractive index modifiers, inorganic particles other than alumina particles and hollow silica particles, and resin particles. When inorganic particles other than alumina particles and hollow silica particles are contained, these inorganic particles may also be surface-treated with a silane coupling agent having a reactive group capable of forming a bond with a polyfunctional (meth)acrylate compound, just like the alumina particles and hollow silica particles. However, the low refractive index layer 16 preferably does not contain a fluorine-containing compound having a fluoroalkyl group. Even if a fluorine-containing compound having a fluoroalkyl group is contained, its content is preferably kept to 1% by mass or less based on the total solids content of the composition for forming the low refractive index layer 16.

[0072] (7) Characteristics of the low refractive index layer In this embodiment, the low refractive index layer 16 has the above-described component composition, and in particular contains a specific long-chain alkyl (meth)acrylate, so that the water contact angle on the surface of the antireflection film 10 is likely to be as large as 90° or more. This indicates that the antireflection film 10 has high antifouling properties. Furthermore, a large water contact angle improves the slipperiness of the surface of the low refractive index layer 16, thereby contributing to improved scratch resistance. From the viewpoint of achieving higher antifouling properties, the water contact angle on the surface of the low refractive index layer 16 is preferably 95° or more, more preferably 100° or more. There is no particular upper limit to the water contact angle on the surface of the low refractive index layer 16, but it is generally 130° or less.

[0073] The refractive index of the low refractive index layer 16 is lower than that of the hard coat layer 14, and is preferably 1.35 or more and 1.53 or less. A refractive index of 1.35 or more allows the inclusion of components that lower the refractive index of the low refractive index layer 16 but increase its strength, thereby making it possible to provide sufficient strength for the low refractive index layer 16 and achieving good scratch resistance. On the other hand, a refractive index of 1.53 or less allows the antireflection film 10 to have an even lower reflectance. From the above viewpoints, the refractive index of the low refractive index layer 16 is more preferably 1.38 or more and 1.50 or less, and even more preferably 1.40 or more and 1.49 or less.

[0074] The average thickness d of the low refractive index layer 16 is preferably in the range of 60 nm to 110 nm. It is more preferably 65 nm or more, and even more preferably 70 nm or more. It is more preferably 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. When the low refractive index layer 16 contains alumina particles, the thickness of the low refractive index layer 16 is measured as the thickness of a relatively smooth portion in the thickness direction that is free from irregularities caused by the alumina particles.

[0075] (Anti-reflection film manufacturing method) To manufacture the anti-reflection film 10, a hard coat layer 14 and a low refractive index layer 16 are formed in this order on the surface of the substrate film 12. To form each layer, a composition for forming the layer is applied, dried as necessary, and then cured by a method appropriate for the curing properties of the composition, such as by irradiation with ionizing radiation such as ultraviolet light. After forming a layer, a composition for forming the next layer is applied, dried as necessary, and then cured. By sequentially repeating this process, a laminated structure of the hard coat layer 14 and the low refractive index layer 16 is formed, and the anti-reflection film 10 can be manufactured.

[0076] A wet method can be suitably used for coating the composition that forms each layer, 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, and various printing methods such as inkjet printing, offset printing, screen printing, and flexographic printing can be used.

[0077] The drying step for each layer is not particularly limited as long as it can remove the solvent used in the coating liquid, but it is preferably carried out at a temperature of 50 to 150° C. for about 10 to 180 seconds.

[0078] For irradiating each layer with ultraviolet light, a high-pressure mercury lamp, an electrodeless (microwave type) lamp, a xenon lamp, a metal halide lamp, or any other ultraviolet light irradiation device can be used. If necessary, ultraviolet light irradiation may be carried out in an inert gas atmosphere such as nitrogen. The ultraviolet light irradiation dose is not particularly limited, but is preferably 50 to 800 mJ / cm. 2 is preferred, and 100 to 300 mJ / cm 2 is more preferred.

[0079] When forming the hard coat layer 14 on the surface of the base film 12, the surface of the base film 12 may be subjected to a surface treatment before coating in order to improve adhesion between the base film 12 and the hard coat layer 14. Examples of surface treatments include corona treatment, plasma treatment, hot air treatment, ozone treatment, and ultraviolet treatment.

[0080] (Anti-reflective film characteristics) The antireflection film 10 having the above-described configuration comprises a substrate film 12, a hard coat layer 14 formed on the surface of the substrate film 12, and a low refractive index layer 16 formed on the surface of the hard coat layer 14. The low refractive index layer 16 is formed from a cured product of an ionizing radiation-curable composition containing a polyfunctional (meth)acrylate compound having a reactive group and a long-chain alkyl (meth)acrylate. Therefore, the low refractive index layer 16 has high antireflection properties and excellent scratch resistance, and can be imparted with high antifouling properties without relying on fluorine-containing compounds, and can maintain its antifouling properties even after long-term use.

[0081] The antireflection film 10 has high antifouling properties, such as a water contact angle of 90° or more, which makes it difficult for fingerprints and other stains to adhere to the surface of the antireflection film 10, and even if they do adhere, they can be easily removed. Furthermore, in the antireflection film 10 according to this embodiment, the long-chain alkyl (meth)acrylate contained in the low refractive index layer 16 has an alkyl group with 16 or more carbon atoms and a linear structure, thereby improving the scratch resistance and abrasion resistance of the antireflection film 10. As such, the antireflection film 10 according to this embodiment has high antireflection properties and antifouling properties as well as high scratch resistance and abrasion resistance, making it particularly suitable for applications that are frequently contacted by fingers, such as those placed on the surface of a touch panel.

[0082] Furthermore, the antireflection film 10 does not need to, and preferably does not, contain a fluorine-containing compound having a fluoroalkyl group in the low refractive index layer 16. Fluorine-containing compounds having a fluoroalkyl group are generally used in antireflection films to adjust the refractive index of the low refractive index layer to a low value or to impart slipperiness and antifouling properties. However, in the present invention, since the low refractive index layer 16 contains a long-chain alkyl (meth)acrylate, sufficient antifouling properties can be obtained without using a fluorine-containing compound having a fluoroalkyl group. By not containing a fluorine-containing compound having a fluoroalkyl group, or by limiting the amount of a fluorine-containing compound to a small amount if present, the antireflection film 10 is less likely to have a negative impact on the environment.

[0083] From the viewpoint of good visibility, the haze of the antireflection film 10 is preferably 2.5% or less, more preferably 2.0% or less, and even more preferably 1.5% or less. The lower the luminous reflectance of the antireflection film 10, the better, and it is preferably 2.0% or less, more preferably 1.5% or less, and even more preferably 1.0% or less. If the luminous reflectance is 2.0% or less, the antireflection film 10 can be considered to have sufficiently high antireflection properties.

[0084] In the antireflection film 10, from the viewpoint of improving the slipperiness, the dynamic friction coefficient (μk) on the surface of the low refractive index layer 16 is preferably 0.5 or less, more preferably 0.2 or less. From the same viewpoint, the static friction coefficient (μs) on the surface of the low refractive index layer 16 is preferably 0.7 or less, more preferably 0.3 or less.

[0085] <Other types of anti-reflection film> Second Embodiment 2 shows an antireflection film 20 according to a second embodiment. The antireflection film 20 according to the second embodiment has a substrate film 12, a hard coat layer 14 formed on the surface of the substrate film 12, a high refractive index layer 15 formed on the surface of the hard coat layer 14, and a low refractive index layer 16 formed on the surface of the high refractive index layer 15.

[0086] The antireflection film 20 according to the second embodiment differs from the antireflection film 10 according to the first embodiment in that it has a high refractive index layer 15 between the hard coat layer 14 and the low refractive index layer 16. Other than this, it is the same as the antireflection film 10 according to the first embodiment, and therefore, a description of the same configuration will be omitted.

[0087] The high refractive index layer 15 is a layer having a refractive index higher than those of the hard coat layer 14 and the low refractive index layer 16. By providing the high refractive index layer 15 between the hard coat layer 14 and the low refractive index layer 16, the antireflection film 20 exhibits a higher antireflection effect. The refractive index of the high refractive index layer 15 is preferably in the range of 1.55 or more and 1.80 or less, and more preferably 1.60 or more and 1.70 or less.

[0088] The material of the high refractive index layer 15 is not particularly limited, and any known material conventionally used in anti-reflection films or the like may be used so as to obtain the desired refractive index. For example, the material may be appropriately selected from the materials described above as usable for the hard coat layer 14 and the low refractive index layer 16. The refractive index of the high refractive index layer 15 can be adjusted by selecting and blending amounts of binder resin, inorganic particles, and resin particles. For example, by adding a sufficient amount of inorganic particles such as solid inorganic oxide particles, a high refractive index layer 15 having a refractive index higher than that of the low refractive index layer 16 can be formed.

[0089] The average thickness of the high refractive index layer 15 varies depending on the refractive index, but by setting it to, for example, 50 nm or more and 200 nm or less, the anti-reflection function can be further enhanced. The high refractive index layer 15 may be formed by laminating two or more layers having different refractive indices.

[0090] (Third embodiment) FIG. 3 shows an antireflection film 30 according to a third embodiment. The antireflection film 30 according to the third embodiment includes a substrate film 12, a hard coat layer 14 formed on one surface of the substrate film 12, and a low refractive index layer 16 formed on the surface of the hard coat layer 14. The substrate film 12 also includes a transparent adhesive layer 22 on the other surface thereof. A release film 24 is disposed on the surface 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 antireflection film 30, and is peeled off from the transparent adhesive layer 22 when the antireflection film 30 is to be used.

[0091] The anti-reflection film 30 of the third embodiment differs from the anti-reflection film 10 of the first embodiment in that it has a transparent adhesive layer 22 on the other side of the base film 12, but is otherwise similar to the anti-reflection film 10 of the first embodiment, and a description of the similar configuration will be omitted.

[0092] The transparent adhesive layer 22 is for adhering the anti-reflection film 30 to the surface of a display or the like with good adhesion. Furthermore, the anti-reflection film 30 has the effect of preventing the glass of a display or the like from shattering, due to the presence of the transparent adhesive layer 22. In other words, the anti-reflection film 30 also functions as a shatterproof film.

[0093] The adhesive composition forming the transparent adhesive layer 22 can contain known adhesive resins such as acrylic adhesives, silicone adhesives, and urethane adhesives. Among these, acrylic adhesives are preferred from the viewpoints of optical transparency and heat resistance. The adhesive composition preferably contains a crosslinking agent to increase the cohesive strength of the transparent adhesive layer 22. Examples of crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, and chelate crosslinking agents.

[0094] The pressure-sensitive adhesive composition may contain additives as needed. Examples of additives include known additives such as plasticizers, silane coupling agents, surfactants, antioxidants, fillers, curing accelerators, and curing retarders. From the viewpoint of productivity, the pressure-sensitive adhesive composition may be diluted with an organic solvent.

[0095] The thickness of the transparent adhesive layer 22 is not particularly limited, but is preferably in the range of 5 μm to 100 μm, more preferably 10 μm or more and 50 μm or less.

[0096] The transparent adhesive layer 22 can be formed by a method of directly applying an adhesive composition onto the other side of the base film 12, a method of applying an adhesive composition onto the side of a release film 24 and then transferring it onto the other side of the base film 12, or a method of applying an adhesive composition onto the side of a first release film and then laminating a second release film, peeling off one of the release films, and transferring it onto the other side of the base film 12, or the like.

[0097] From the viewpoint of preventing glass from scattering, the transparent adhesive layer 22 preferably has an adhesive strength to glass of 4 N / 25 mm or more, more preferably 6 N / 25 mm or more, and even more preferably 10 N / 25 mm or more.

[0098] (Fourth embodiment) 4 shows an antireflection film 40 according to a fourth embodiment. The antireflection film 40 according to the fourth embodiment includes a substrate film 12, a hard coat layer 14 formed on one surface of the substrate film 12, a low refractive index layer 16 formed on the surface of the hard coat layer 14, and a protective film 28 disposed on the surface of the low refractive index layer 16 via an adhesive layer 26. The other surface of the substrate film 12 also includes a transparent adhesive layer 22. A release film 24 is disposed on the surface of the transparent adhesive layer 22, if necessary.

[0099] The anti-reflection film 40 according to the fourth embodiment differs from the anti-reflection film 30 according to the third embodiment in that it has a protective film 28 on the surface of the low refractive index layer 16 via an adhesive layer 26, but is otherwise similar to the anti-reflection film 30 according to the third embodiment, and therefore a description of the similar configuration will be omitted.

[0100] The protective film 28 prevents scratches on the surface of the low refractive index layer 16 when the antireflection film 40 is handled, for example, during continuous processing by a roll process or when it is attached to a display or the like. The protective film 28 is attached to the surface of the low refractive index layer 16 via the adhesive layer 26. After processing of the antireflection film 40, the protective film 28 is peeled off from the surface of the low refractive index layer 16 together with the adhesive layer 26. For this reason, the adhesive layer 26 is adjusted so that the adhesive strength between the protective film 28 and the adhesive layer 26 is stronger than the adhesive strength between the low refractive index layer 16 and the adhesive layer 26, allowing for interfacial peeling between the low refractive index layer 16 and the adhesive layer 26. In the antireflection film 40 according to this embodiment, the surface properties, such as the water contact angle and friction coefficient, are determined for the surface in a state in which the protective film 28 and the adhesive layer 26 have been peeled off.

[0101] The material constituting the protective film 28 can be appropriately selected from the materials exemplified as the material constituting the base film 12. The thickness of the protective film 28 is not particularly limited, but can be in the range of 2 μm to 500 μm, or in the range of 2 μm to 200 μm.

[0102] The adhesive layer 26 may suitably be one described in International Publication No. 2021 / 020504 filed by the present applicant. The adhesive forming the adhesive layer 26 is not particularly limited, and acrylic adhesives, silicone adhesives, urethane adhesives, and the like may be suitably used. Acrylic adhesives are particularly suitable due to their excellent transparency and heat resistance. The acrylic adhesive is preferably formed from an adhesive composition containing a (meth)acrylic polymer and a crosslinking agent.

[0103] The (meth)acrylic polymer is a homopolymer or copolymer of a (meth)acrylic monomer. Examples of the (meth)acrylic monomer include an alkyl group-containing (meth)acrylic monomer, a carboxyl group-containing (meth)acrylic monomer, and a hydroxyl group-containing (meth)acrylic monomer.

[0104] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a metal chelate-based crosslinking agent, a metal alkoxide-based crosslinking agent, a carbodiimide-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a melamine-based crosslinking agent, etc. These crosslinking agents may be used alone or in combination of two or more.

[0105] The pressure-sensitive adhesive composition may contain other additives in addition to the (meth)acrylic polymer and crosslinking agent. 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 deactivators, alkylating agents, and flame retardants. These additives are appropriately selected and used depending on the application and purpose of the pressure-sensitive adhesive.

[0106] The thickness of the adhesive layer 26 is not particularly limited, but is preferably in the range of 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 7 μm or less.

[0107] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention.

[0108] For example, in the above embodiment, it is described that the surface of the base film 12 may be subjected to a surface treatment, but instead of the surface treatment, an easy-adhesion layer may be provided on the surface of the base film 12.

[0109] As shown in Fig. 3, the transparent adhesive layer 22 and the release film 24 in the third embodiment are shown as being added to the antireflection film 10 of the first embodiment shown in Fig. 1, but they may also be added to the antireflection film 20 of the second embodiment shown in Fig. 2. Furthermore, as shown in Fig. 4, the adhesive layer 26 and the protective film 28 in the fourth embodiment are shown as being added to the antireflection film 30 of the third embodiment shown in Fig. 3, but they may also be added to the antireflection film 10 of the first embodiment shown in Fig. 1 or the antireflection film 20 of the second embodiment shown in Fig. 2.

[0110] Before forming each layer, various functional layers such as a gas barrier improving layer, an antistatic layer, and an oligomer block layer may be provided in advance on the surface of the base film 12. As the antistatic layer, those described in International Publication No. 2021 / 020504 filed by the present applicant can be suitably applied.

[0111] In any embodiment, it is preferable that not only the low refractive index layer 16 but also each layer formed on the surface of the base film 12 does not contain a fluorine-containing compound having a fluoroalkyl group, which makes the antireflection film less likely to have adverse effects on the environment. [Example]

[0112] The present invention will be described in detail below using examples and comparative examples. Unless otherwise specified, the preparation and evaluation of samples were carried out at room temperature in the atmosphere.

[0113] <Preparation of Samples for Examples 1 to 7 and Comparative Examples 1 to 4> (Preparation of hard coat layer-forming composition) A photopolymerization initiator "Omnirad127" (manufactured by IGM Resins BV) was added to an ultraviolet-curable resin composition "ESS-620" (manufactured by DIC; urethane acrylate resin, solvent (ethyl acetate); solid content 79% by mass) so that the amount was 3% by mass relative to the total amount of the composition for forming a hard coat layer. Further, ethyl acetate was added so that the solid content was 31% by mass, thereby preparing a composition for forming a hard coat layer.

[0114] (Preparation of composition for forming high refractive index layer) A composition for forming a high refractive index layer was prepared by adding methyl ethyl ketone to an ultraviolet-curable resin composition "TYZ65-01" (manufactured by Toyochem; acrylic resin, zirconium oxide (average particle size 80 nm), photopolymerization initiator (the above-mentioned "Omnirad127"), solvent (cyclohexanone, methyl isobutyl ketone, propylene glycol monomethyl ether); solids concentration 35% by mass) so that the solids concentration was 8% by mass.

[0115] (Preparation of Alumina Particles) 25 g of untreated alumina particles (average particle size 160 nm), 2.5 g of a silane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM-5103"; 3-acryloxypropyltrimethoxysilane), and 72.5 g of propylene glycol monomethyl ether were mixed and dispersed at 4000 rpm for 30 minutes using a homomixer (Primix Corporation "Homomixer MARK II 2.5 type") to obtain a dispersion of alumina particles surface-treated with a silane coupling agent having an acryloyl group as a reactive group. The alumina particles surface-treated with a silane coupling agent having a reactive group prepared here may be referred to simply as alumina particles below.

[0116] (Preparation of composition for forming low refractive index layer) A composition for forming a low refractive index layer was prepared by blending a polyfunctional acrylate, an alkyl (meth)acrylate (a (meth)acrylate having an alkyl group), a silicone compound, the alumina particles prepared above, hollow silica particles, and a photopolymerization initiator to obtain the composition (mass % of the total solid content) shown in Table 1, and adjusting the solid content concentration to 3.5 mass % using a solvent (MEK / cyclohexanone = 7 / 3).

[0117] The materials used for the composition for forming the low refractive index layer are as follows. Multifunctional acrylate: Toagosei "Aronix M-403"; a mixture of dipentaerythritol penta- and hexaacrylates; acrylic equivalent 100 eq; solids concentration 100% by mass BEA: Behenyl acrylate (Tokyo Chemical Industry Co., Ltd.) - an acrylate with a linear alkyl group containing 22 carbon atoms SA: Stearyl acrylate (Tokyo Chemical Industry Co., Ltd.) - an acrylate with a linear alkyl group containing 18 carbon atoms LA: Lauryl acrylate (Tokyo Chemical Industry Co., Ltd.) - an acrylate with a linear alkyl group containing 12 carbon atoms iSA: Isostearyl acrylate (Osaka Organic Chemical Industry Co., Ltd.) - an acrylate with a branched alkyl group containing 18 carbon atoms DTDA: 2-decyltetradecyl acrylate (Atomax Chemicals) - an acrylate with a branched alkyl group containing 22 carbon atoms Silicone compound: Shin-Etsu Chemical Co., Ltd. "KF-2012"; one-terminated methacrylic-modified silicone oil; functional group equivalent weight 4600 g / mol Hollow silica particles: "Sururia 4320" manufactured by JGC Catalysts and Chemicals; hollow silica particles surface-treated with a silane coupling agent containing a methacryloyl group as a reactive group; average particle diameter 60 nm; solid content 20% by mass Photopolymerization initiator: "Omnirad127"

[0118] (Preparation of hard coat layer) For each of Examples 1 to 7 and Comparative Examples 1 to 4, the composition for forming a hard coat layer was applied to a substrate film (Toray's "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 a high-pressure mercury lamp at a light intensity of 200 mJ / cm. 2 The coated film was irradiated with ultraviolet light to form a hard coat layer (film thickness: 4 μm).

[0119] (Preparation of high refractive index layer) For each of Examples 1 to 7 and Comparative Examples 1 to 4, a composition for forming a high refractive index layer was applied onto the surface of the hard coat layer, dried at 80°C for 60 seconds, and then irradiated with a high-pressure mercury lamp at a light intensity of 200 mJ / cm under a nitrogen atmosphere. 2 The film was irradiated with ultraviolet light to form a high refractive index layer (thickness: 110 nm).

[0120] (Preparation of low refractive index layer) For each of Examples 1 to 7 and Comparative Examples 1 to 4, the composition for forming a low refractive index layer prepared above was applied onto the surface of the high refractive index layer using a #3 wire bar, dried at 80°C for 60 seconds, and then irradiated with a high-pressure mercury lamp at a light intensity of 200 mJ / cm under a nitrogen atmosphere. 2 The film was irradiated with ultraviolet light of 1000 kJ / cm 2 , and a low refractive index layer was formed to prepare an anti-reflection film.

[0121] <Evaluation method> (Thickness and refractive index of each layer) For each sample, the thickness and refractive index of each of the hard coat layer, high refractive index layer, and low refractive index layer were evaluated. At this time, each time each layer was formed, the reflection spectrum in the wavelength range of 380 to 780 nm obtained using a microspectrophotometer (Otsuka Electronics' "OPTM-F1") and the theoretical spectrum derived based on the Fresnel equation were curve-fitted by the least squares method to calculate the thickness and refractive index of each layer at a wavelength of 550 nm.

[0122] (water contact angle) The water contact angle was measured on the surface of the anti-reflection film thus prepared. A contact angle meter (DropMaster DMo-502, manufactured by Kyowa Interface Science Co., Ltd.) was used to measure the water contact angle by dropping 4 μL of pure water onto the surface of the sample (the surface of the low refractive index layer). A water contact angle of 90° or more can be considered sufficiently large from the viewpoint of antifouling properties.

[0123] (Scratch resistance) A steel wool resistance test was conducted for each sample. A flat abrasion tester (Daiei Scientific Instruments Manufacturing Co., Ltd., "DAS-400") was used. Steel wool #0000 (Japan Steel Wool Co., Ltd.) fixed to a 20 mm x 20 mm flat abrader was placed on the surface of the anti-reflection film of each sample and reciprocated. The stroke length of the test stand was 50 mm, the test stand reciprocation speed was 60 reciprocations / min, and the applied load was 1 kg. The sample was visually observed every 500 reciprocations, and the maximum number of reciprocations until a scratch of 10 mm or more in length was observed was used as the evaluation value. A rating of 500 or more reciprocations can be considered to have sufficient abrasion resistance. Furthermore, a rating of 1000 or more reciprocations can be considered to have high abrasion resistance, and a rating of 1500 or more reciprocations can be considered to have particularly high abrasion resistance.

[0124] (wear resistance) The abrasion resistance of each sample was evaluated by an eraser abrasion test using the water contact angle as an index. A flat abrasion tester (Daiei Scientific Instruments Manufacturing Co., Ltd., "DAS-400") was used. An eraser for the eraser abrasion test (Minoan, cylindrical with a contact surface diameter of 6 mm) was placed on the surface of the anti-reflective film of each sample and reciprocated. The stroke length of the test table was 50 mm, the test table reciprocation speed was 30 reciprocations / min, and the applied load was 1.0 kg. The water contact angle was measured every 100 reciprocations up to 500 reciprocations, and every 500 reciprocations thereafter. The maximum number of reciprocations at which a water contact angle of 90° or greater was maintained was used as the evaluation value. A rating of 500 or more reciprocations was considered to indicate sufficient abrasion resistance. Furthermore, a rating of 1000 or more reciprocations was considered to indicate high abrasion resistance. The water contact angle was measured using a contact angle meter (DropMaster DMo-502, manufactured by Kyowa Interface Science Co., Ltd.) by dropping 4 μL of pure water onto the surface of the anti-reflection film.

[0125] (Luminous reflectance) The back surface of the prepared anti-reflection film (the surface opposite the low refractive index layer) was roughened with #400 sandpaper and painted over with black paint. The 5° specular reflectance of the surface of the anti-reflection film at wavelengths of 380 nm to 780 nm was measured using an ultraviolet-visible-near-infrared spectrophotometer (Shimadzu Corporation, "UV-3600"), and this measurement value was multiplied by the relative luminous efficiency value to calculate the luminous reflectance. A luminous reflectance of 2.0% or less can be considered to be sufficient anti-reflection properties.

[0126] (Hayes) The haze of the entire anti-reflection film was measured using the Nippon Denshoku Haze Meter NDH8000 according to the method of JIS-K7136. If the haze is 2.0% or less, the anti-reflection film can be said to have sufficient transparency.

[0127] (dynamic friction coefficient, static friction coefficient) Using a static and dynamic friction measuring device (Trinity Lab's "Tribomaster TL201Ts"), the friction force between the surface of the low refractive index layer of the sample anti-reflection film and a tactile contact (finger model) was measured. The static and dynamic friction coefficients μs and μk of the surface of the low refractive index layer were obtained from the measured friction force. The measurement conditions were a load of 200 g, a speed of 1.7 mm / s, and a distance of 50 mm. If the dynamic friction coefficient μk is 0.5 or less and the static friction coefficient μs is 0.7 or less, the anti-reflection film can be considered to have sufficiently high slip properties.

[0128] <Evaluation results> Table 1 shows the component composition of the low refractive index layer (unit: mass % of the total solid content of the low refractive index layer) and the layer structure of the antireflection film for Examples 1 to 7 and Comparative Examples 1 to 4, as well as the evaluation results.

[0129] [Table 1]

[0130] As shown in Table 1, in all of Examples 1 to 7, the low refractive index layer contains a polyfunctional (meth)acrylate compound having a reactive group and either BEA or SA, a (meth)acrylate compound having a linear alkyl group with 16 or more carbon atoms. This corresponds to high scratch resistance and abrasion resistance, evaluated as 500 cycles or more. Furthermore, the water contact angle of the antireflection film surface is 90° or greater, indicating that the antireflection film has high antifouling properties. Among these, Examples 1 to 3 exhibit particularly high scratch resistance and abrasion resistance due to the use of highly crystalline behenyl acrylate (BEA). Furthermore, Examples 6 and 7, which contain a silicone compound in the low refractive index layer, exhibit low dynamic and static friction coefficients of 0.2 or less and 0.3 or less, respectively, indicating high slippage in addition to scratch resistance and abrasion resistance. Furthermore, all of Examples 1 to 7 have physical properties such as high scratch resistance, abrasion resistance, and antifouling properties, and also optical properties such as high antireflection properties indicated by a luminous reflectance of 2.0% or less and high transparency indicated by a haze of 2.0% or less.

[0131] On the other hand, in Comparative Example 1, although the low refractive index layer contains an alkyl (meth)acrylate compound (LA), the number of carbon atoms in the alkyl group of the alkyl (meth)acrylate compound is less than 16. Correspondingly, the scratch resistance evaluation value is less than 500 times, and the abrasion resistance evaluation value is significantly less than 500 times, indicating insufficient scratch resistance and abrasion resistance. In addition, the antifouling property evaluated by the water contact angle and the slipperiness evaluated by the small coefficient of dynamic friction and static friction are also low.

[0132] Comparative Examples 2 and 3 contain alkyl (meth)acrylate compounds (iSA, DTDA), and although the alkyl group in these alkyl (meth)acrylate compounds has 16 or more carbon atoms, the alkyl group is branched. Correspondingly, in both Comparative Examples 2 and 3, the evaluation value for scratch resistance was less than 500 times, indicating insufficient scratch resistance. In particular, the isostearyl acrylate (iSA) used in Comparative Example 2 has a low degree of crystallinity, and therefore, in Comparative Example 2, the evaluation value for abrasion resistance was also less than 500 times, indicating insufficient abrasion resistance. Comparative Example 2 also exhibits poor stain resistance, as evaluated by the water contact angle, and poor slip resistance, as evaluated by the small coefficients of dynamic and static friction.

[0133] Comparative Example 4 contains a silicone compound, which gives it high stain resistance and slip resistance, but it does not contain any alkyl (meth)acrylate compounds, including those with a linear alkyl group having 16 or more carbon atoms, and therefore its scratch resistance and abrasion resistance are insufficient.

[0134] As described above, an antireflection film has a substrate film, a hard coat layer formed on the surface of the substrate film, and a low refractive index layer formed on the surface of the hard coat layer, and the low refractive index layer is composed of a cured product of an ionizing radiation-curable composition containing a polyfunctional (meth)acrylate compound having a reactive group and a (meth)acrylate compound having a linear alkyl group having 16 or more carbon atoms, thereby providing the antireflection film with excellent antifouling properties, scratch resistance, and abrasion resistance. Furthermore, because the antireflection film does not contain a fluorine-containing compound having a fluoroalkyl group, it is less likely to have an adverse effect on the environment.

[0135] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0136] 10,20,30,40 Anti-reflective film 12 Base film 14 Hard coat layer 15 High refractive index layer 16 Low refractive index layer 22 Transparent adhesive layer 24 Release film 26 Adhesive layer 28 Protective Film

Claims

1. a substrate film, a hard coat layer formed on a surface of the substrate film, and a low refractive index layer formed on the surface of the hard coat layer; The low refractive index layer is An anti-reflection film formed from a cured product of an ionizing radiation-curable composition containing a polyfunctional (meth)acrylate compound having a reactive group and a monofunctional (meth)acrylate compound having an alkyl group with a linear structure and having 16 or more carbon atoms.

2. The anti-reflection film according to claim 1 , wherein the low refractive index layer does not contain a fluorine-containing compound having a fluoroalkyl group.

3. the antireflection film comprises a high refractive index layer and the low refractive index layer in this order on a surface of the hard coat layer, 3. The antireflection film according to claim 1, wherein the high refractive index layer has a refractive index at a wavelength of 550 nm that is higher than the refractive index of the hard coat layer and higher than the refractive index of the low refractive index layer.

4. 3. The anti-reflection film according to claim 1, wherein the low refractive index layer further contains alumina particles that have been surface-treated with a silane coupling agent having a reactive group capable of forming a bond with the polyfunctional (meth)acrylate compound.

5. 3. The anti-reflection film according to claim 1, wherein the low refractive index layer further contains hollow silica particles that have been surface-treated with a silane coupling agent having a reactive group capable of forming a bond with the polyfunctional (meth)acrylate compound.

6. 3. The anti-reflection film according to claim 1, wherein the low refractive index layer further contains a silicone compound having a reactive group capable of forming a bond with the polyfunctional (meth)acrylate compound.

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