Anti-reflection film

Abstract

Provided is an anti-reflection film which has excellent anti-reflection properties and antifouling properties, is not susceptible to wear marks or damage even with repeated wiping, and has high wear resistance. An anti-reflection film (10) having a base film (12), a hard coat layer (14) formed on a surface of the base film (12), a low refractive index layer (16) formed on a surface of the hard coat layer (14), and an antifouling layer (18) formed on a surface of the low refractive index layer (16), the antifouling layer (18) being configured from a cured product of a composition containing a fluorine-containing (meth) acrylate, the amount of the solid content of the antifouling layer (18) being less than the amount of the solid content of the antifouling layer (18) being less than the total amount of the solid content of the antifouling layer (18), and the amount of the solid content of the antifouling layer (18) being less than the total amount of the solid content of the antifouling layer (18) being less than the total amount of the solid content of the antifouling layer (18). The content of fluorine-containing (meth) acrylate in the antifouling layer (18) is 90% by mass or more, and 50% by mass or more of the solid content of the fluorine-containing (meth) acrylate is a fluorine-containing (meth) acrylate having a surface free energy polar component [gamma] p of 18 mN / m or more.

Description

Technical Field

[0001] The present invention relates to an antireflection film, and more particularly, to an antireflection film suitable for the surface of a display such as a touch panel of a liquid crystal display, an organic EL display, a smartphone, or the like. Background Art

[0002] In order to prevent external light from entering a screen or the like, an antireflection film is sometimes disposed on the surface of a display such as a touch panel of a liquid crystal display, an organic EL display, a smartphone, or the like. As characteristics required for the antireflection film, optical characteristics such as a low reflectance and a high transmittance, and physical and chemical characteristics such as a high hardness, abrasion resistance, chemical resistance, and antifouling property can be cited. Moreover, in a display accompanied by contact of a finger, such as a touch panel display, it is necessary to remove dirt such as fingerprints by wiping with a cloth or the like. Centering on the antireflection film used in these displays, in recent years, there has been a demand for improving the resistance when the antireflection film is rubbed with a cloth or a felt material.

[0003] Conventionally, as a test for evaluating the resistance of an antireflection film to contact with an external object, a scratch resistance test for evaluating damage to the film when a load is applied to a steel wool in contact with the film surface and it is reciprocated has generally been used. However, in recent years, in applications such as automotive touch panels, when ensuring durability in actual use accompanied by wiping with a cloth or the like is assumed, the level of scratch resistance evaluated by the above-described abrasion test using steel wool does not necessarily become a good indicator for ensuring high durability. There is a demand for an antireflection film having high abrasion resistance in the sense of durability when actually wiping a display with a cloth or the like.

[0004] For example, Patent Document 1 discloses an antireflection film that has antifouling properties and is not easily damaged by repeated wiping or wiping with a hard cotton cloth or the like by using a specified amount of alumina particles, hollow silica fine particles, and a fluorine-containing compound in a low refractive index layer disposed on the outermost surface of the antireflection film.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-092645 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] As disclosed in Patent Document 1, in a conventional antireflection film, the low refractive index layer disposed on the outermost surface includes low refractive index nanoparticles such as hollow silica, a binder such as polyfunctional acrylate, and a fluorine-based additive. The strength of the low refractive index layer having such a composition is weak, and when a wear resistance test is performed, damage or peeling of the coating film easily occurs. On the other hand, by using a layer including inorganic oxide particles and polyfunctional acrylate, which may have high strength, as the low refractive index layer on the outermost surface, the strength may sometimes be improved. However, in this case, since the refractive index of these substances is high, the reflectance of the obtained antireflection film becomes high.

[0010] In addition, the following method is also used: on the surface of the low refractive index layer, as a layer independent of the low refractive index layer, an antifouling layer containing a substance having an antifouling effect such as a fluorine-based additive is provided. However, even when the antifouling layer is provided, there are cases where sufficient antifouling properties cannot be obtained, or the antifouling properties decrease due to surface wear when repeatedly wiped by finger contact or a cloth. In an antireflection film that is frequently touched or wiped by fingers, in addition to requiring high antireflection properties and antifouling properties, high durability against repeated wiping is also required. As the durability against wiping, it means that not only is it not easily damaged during wiping, but also wear marks formed due to changes in reflection characteristics are not easily formed at the wiped parts, and it is important to have high wear resistance.

[0011] The problem to be solved by the present invention is to provide an antireflection film having excellent antireflection properties, antifouling properties, and being not easily damaged by repeated wiping, and having high wear resistance.

[0012] Solutions for Solving the Problems

[0013] To solve the above problems, the antireflection film according to the present invention has the following configuration.

[0014] [1] The antireflection film according to the present invention has a substrate film, a hard coat formed on the surface of the substrate film, a low refractive index layer formed on the surface of the hard coat, and an antifouling layer formed on the surface of the low refractive index layer. The antifouling layer is composed of a cured product of a composition containing a fluorine-containing (meth)acrylate. Based on the total amount of the solid components of the antifouling layer, the content of the fluorine-containing (meth)acrylate in the antifouling layer is 90% by mass or more, and 50% by mass or more of the solid components of the fluorine-containing (meth)acrylate contained in the antifouling layer are fluorine-containing (meth)acrylates having a surface free energy polar component γp of 18 mN / m or more.

[0015] [2] In the above aspect [1], it may be that the total amount of the resin components constituting the antifouling layer is a fluorine-containing (meth)acrylate.

[0016] [3] In the above scheme [1] or [2], the polar component γp of the surface free energy contained in the anti-fouling layer may be 18 mN / m or more, the hydrogen bonding component γh of the surface free energy of the fluorine-containing (meth)acrylate may be 8 mN / m or less, and the dispersion component γd may be 8 mN / m or more and 40 mN / m or less.

[0017] Effects of the Invention

[0018] The antireflection film of the present invention having the structure of [1] above comprises a substrate film, a hard coating layer formed on a surface of the substrate film, a low refractive index layer formed on a surface of the hard coating layer, and an antifouling layer formed on a surface of the low refractive index layer, wherein the antifouling layer is composed of a cured product of a composition containing a fluorine-containing (meth)acrylate, the content of the fluorine-containing (meth)acrylate in the antifouling layer is 90% by mass or more based on the total solid content of the antifouling layer, and 50% by mass or more of the solid content of the fluorine-containing (meth)acrylate contained in the antifouling layer is a fluorine-containing (meth)acrylate having a polar component γp of surface free energy of 18 mN / m or more, thereby having excellent antireflection properties and antifouling properties, and is not prone to abrasion marks or damage even by repeated wiping, and has high abrasion resistance.

[0019] In the above-mentioned embodiment [2], the total amount of the resin component constituting the antifouling layer is fluorine-containing (meth)acrylate. When a fluorine-free binder resin is added to the antifouling layer, there is a possibility that the antireflection film has an effect of improving the wear resistance by improving the adhesion of the antifouling layer to the low refractive index layer. However, the antireflection film according to the present invention has sufficiently high wear resistance because the antifouling layer contains 90% by mass or more of fluorine-containing (meth)acrylate as described in the above-mentioned embodiment [1], and 50% by mass or more of the fluorine-containing (meth)acrylate is fluorine-containing (meth)acrylate having a polar component γp of surface free energy of 18 mN / m or more. Therefore, it is not necessary to add a fluorine-free binder resin to the antifouling layer for the purpose of improving the wear resistance.

[0020] In the above-mentioned embodiment [3], the polar component γp of the surface free energy contained in the antifouling layer is 18 mN / m or more, the hydrogen bonding component γh of the surface free energy of the fluorine-containing (meth)acrylate is 8 mN / m or less, and the dispersion component γd is 8 mN / m or more and 40 mN / m or less. By making the hydrogen bonding component γh as described above, the antifouling effect of the antifouling layer becomes higher. In addition, by making the dispersion component γd as described above, it is easy to suppress the aggregation of the fluorine-containing (meth)acrylate, and the antifouling layer is formed into a uniform coating film. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1It is a cross-sectional view of the antireflection film related to the first embodiment of the present invention.

[0022] Figure 2 It is a cross-sectional view of the antireflection film related to the second embodiment of the present invention.

[0023] Figure 3 It is a cross-sectional view of the antireflection film related to the third embodiment of the present invention.

[0024] Figure 4 It is a cross-sectional view of the antireflection film related to the fourth embodiment of the present invention. Detailed Embodiment

[0025] Hereinafter, the present invention will be described in detail. In this specification, unless otherwise specified, various physical properties refer to values at room temperature and in the atmosphere. In addition, in this specification, unless otherwise specified, the refractive index of a substance and a material layer refers to the refractive index at a measurement wavelength of 589.3 nm.

[0026] <Antireflection Film of the First Embodiment>

[0027] Figure 1 It is a cross-sectional view of the antireflection film 10 related to the first embodiment of the present invention. As Figure 1 shown, the antireflection film 10 related to the first embodiment of the present invention has: a substrate film 12; a hard coat 14 formed on the surface of the substrate film 12; a low refractive index layer 16 formed on the surface of the hard coat 14; and an antifouling layer 18 formed on the surface of the low refractive index layer 16. In this embodiment, the above-mentioned layers are laminated in sequence without other layers in between. The antifouling layer 18 becomes the layer exposed on the outermost surface of the antireflection film 10 as a whole.

[0028] (Substrate Film)

[0029] The substrate film 12 only needs to have transparency and is not particularly limited. Examples of the substrate film 12 include a transparent polymer film and a glass film. Transparency means that the total light transmittance in the visible light wavelength region 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 particularly limited, but from the viewpoints of excellent operability and the like, it is preferably in the range of 2 μm or more and 500 μm or less. More preferably, it is in the range of 2 μm or more and 200 μm or less. In addition, a "film" generally refers to a film with a thickness less than 0.25 mm, but if the thickness is 0.25 mm or more and it can be wound into a roll, even a film with a thickness of 0.25 mm or more is included in the "film".

[0030] Examples of the polymer material 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, polyolefin resins such as polycycloolefin resin and cycloolefin copolymer resin, 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 polymer material of the base film 12 may be composed of only one of them or a combination of two or more. Among them, from the viewpoints of optical properties and durability, polyethylene terephthalate resin, polyimide resin, polycarbonate resin, poly(meth)acrylate resin, polycycloolefin resin, cycloolefin copolymer resin, and triacetyl cellulose resin are more preferable.

[0031] The base film 12 may be composed of a single layer including a layer containing one or two or more of the above polymer materials, or may be composed of two or more layers such as a layer containing one or two or more of the above polymer materials and a layer containing one or two or more polymer materials different from that layer.

[0032] (Hard coat)

[0033] The hard coat 14 helps to improve the scratch resistance of the antireflection film 10. The hard coat 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 having energy quanta capable of polymerizing or crosslinking molecules among electromagnetic waves or charged particle beams. Examples of ionizing radiation include electromagnetic waves such as ultraviolet rays (UV), X-rays, and γ-rays, and charged particle beams such as electron beams (EB), α-rays, and ion beams. Among them, ultraviolet rays (UV) are particularly preferable from the viewpoint of productivity. Hereinafter, the ionizing radiation curable composition may be simply referred to as the curable composition. In addition, in this specification, "(meth)acrylate" means "at least one of acrylate and methacrylate". "(Meth)acryloyl" means "at least one of acryloyl and methacryloyl". "(Meth)acrylic acid" means "at least one of acrylic acid and methacrylic acid". A "(meth)acrylate compound" is a compound having a (meth)acryloyl group, and examples thereof include monomers, oligomers, and prepolymers. Hereinafter, the "(meth)acrylate compound" may be simply referred to as (meth)acrylate.

[0034] (Meth)acrylate may be a monofunctional (meth)acrylate or a polyfunctional (meth)acrylate. Alternatively, it may also be composed of a combination of a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate. From the viewpoint of improving curability, etc., the curable composition more preferably contains a polyfunctional (meth)acrylate as the (meth)acrylate.

[0035] Examples of the (meth)acrylate include urethane (meth)acrylate, silicone (meth)acrylate, alkyl (meth)acrylate, aryl (meth)acrylate, etc. Among them, urethane (meth)acrylate is preferred, and urethane (meth)acrylate oligomer is particularly preferred. Specific examples of the urethane (meth)acrylate include substances obtained by reacting a polyisocyanate compound, a hydroxy group-containing (meth)acrylate compound, and, if necessary, a polyol compound. Examples of the polyisocyanate compound include diisocyanate compounds such as hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and their allophanate-modified products, adduct-modified products, biuret-modified products, etc. Examples of the hydroxy group-containing (meth)acrylate compound include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, trimethylolpropane diacrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and their polyoxyalkylene-modified products, polylactone-modified products, etc. Examples of the polyol compound include ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, glycerin, trimethylolpropane, pentaerythritol, bisphenol, etc.

[0036] When the curable composition for forming the hard coat 14 contains urethane (meth)acrylate as the ultraviolet curable resin, since the hard coat 14 has appropriate flexibility, the bending resistance of the antireflection film 10 becomes high, and it can be suitably used for flexible displays that are repeatedly bent, such as foldable displays or rollable displays. In addition, for example, even if the substrate film 12 is formed of a polycycloolefin or a cycloolefin copolymer, etc., and is relatively easy to break, it is also easy to suppress the breakage of the substrate film 12.

[0037] As the (meth)acrylate constituting the curable composition, it preferably 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, tripentaerythritol octa(meth)acrylate, etc. It is particularly preferred to contain pentaerythritol tri(meth)acrylate in the curable composition.

[0038] In the curable composition for forming the hard coat 14, in addition to the ultraviolet curable resin, a non-ultraviolet curable resin may also be contained, but it may not be contained. Further, in the curable composition for forming the hard coat 14, a photoinitiator may also be contained. Additionally, as needed, additives and the like that are usually added to the curable composition may be contained. Examples of the additives include dispersants, leveling agents, defoaming agents, thixotropic agents, antifouling agents, antibacterial agents, flame retardants, slip agents, antistatic agents, inorganic particles, resin particles, etc. Further, as needed, a solvent may also be contained.

[0039] Examples of the non-ultraviolet curable resin include thermoplastic resins and thermosetting resins. Examples of the thermoplastic resin include polyester resins, polyether resins, polyolefin resins, polyamide resins, etc. Examples of the thermosetting resin include unsaturated polyester resins, epoxy resins, alkyd resins, phenolic resins, etc.

[0040] Examples of the photopolymerization initiator include alkylbenzophenone-based, acylphosphine oxide-based, and oxime ester-based photopolymerization initiators. Examples of the alkylbenzophenone-based photopolymerization initiator include 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-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, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-(4-morpholinophenyl)-1-butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, N,N-dimethylaminobenzophenone, and the like. Examples of the acylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, and the like. Examples of the oxime ester-based photopolymerization initiator include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), acetophenone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyl oxime), and the like. The photopolymerization initiator may be used alone or in combination of two or more kinds.

[0041] Based on the total amount of the solid components of the curable composition, the content of the photopolymerization initiator is preferably in the range of 0.1% by mass or more and 10% by mass. More preferably, it is 1% by mass or more and 5% by mass or less.

[0042] The inorganic particles and resin particles can be added to the hard coat 14, for example, for the purpose of preventing adhesion of the hard coat 14, adjusting the refractive index of the hard coat 14, and imparting antiglare properties. By forming minute surface irregularities in the hard coat 14 with the added inorganic particles or resin particles, it is easy to suppress adhesion between the front and back surfaces when winding the hard coat film including the substrate film 12 and the hard coat 14 into a roll shape before forming the low refractive index layer 16.

[0043] Examples of the inorganic particles capable of adjusting the refractive index of the hard coat 14 include metal oxide particles including oxides of metals such as titanium, zirconium, tin, zinc, silicon, niobium, aluminum, chromium, magnesium, germanium, gallium, antimony, and platinum. As the inorganic particles capable of optical adjustment, one kind can be used alone, or two or more kinds can be used in combination. Among them, titanium oxide and zirconium oxide are particularly preferred from the viewpoints of excellent balance between high refractive index and transparency. Examples of the resin particles include resin particles including 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. As the resin particles, one kind can be used alone, or two or more kinds can be used in combination.

[0044] The thickness of the hard coat 14 is not particularly limited, but from the viewpoints of having sufficient hardness and the like, it is preferably 0.5 μm or more. More preferably, it is 0.75 μm or more. Further, from the viewpoints of easily suppressing curling and the like caused by the difference in thermal shrinkage from the substrate film 12, it is preferably 20 μm or less. More preferably, it is 10 μm or less. The thickness of the hard coat 14 refers to the thickness of the relatively smooth portion in the portion without unevenness caused by inorganic particles or resin particles in the thickness direction.

[0045] From the viewpoint of suppressing interference unevenness caused by the difference in refractive index between the substrate film 12 and the hard coat 14, the refractive index of the hard coat 14 is preferably in the range of 1.49 or more and 1.56 or less.

[0046] From the viewpoint of suppressing adhesion and the like, the arithmetic mean roughness Ra of the surface with surface unevenness formed on the hard coat 14 is preferably in the range of 0.3 nm or more and 20 nm or less. More preferably, it is 0.5 nm or more, and further, it is 10 nm or less.

[0047] Examples of the solvent used in the curable composition for forming the hard coat 14 include alcohol solvents such as ethanol, isopropyl alcohol (IPA), n-butanol (NBA), ethylene glycol monomethyl ether (EGM), ethylene glycol monoisopropyl ether (IPG), propylene glycol monomethyl ether (PGM), and diethylene glycol monobutyl ether; ketone solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, and acetone; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate (EtAc), propyl acetate, isopropyl acetate, and butyl acetate (BuAc); amide solvents such as N-methylpyrrolidone, acetamide, and dimethylformamide. As the solvent, one kind can be used alone, or two or more kinds can be used in combination.

[0048] The solid content concentration of the curable composition (the concentration of components other than the solvent) may be appropriately determined in consideration of coatability, film thickness, etc. For example, it may be set to 1% by mass or more and 90% by mass or less, 1.5% by mass or more and 80% by mass or less, 2% by mass or more and 70% by mass or less, etc.

[0049] (Low refractive index layer)

[0050] In the antireflection film 10 according to the present embodiment, a low refractive index layer 16 is provided on the surface of the hard coat 14 as an antireflection layer. The low refractive index layer 16 has a refractive index lower than that of the hard coat 14, and exhibits an antireflection effect due to the refractive index difference from the hard coat 14.

[0051] The composition of the low refractive index layer 16 is not particularly limited, but it is preferably composed of a cured product of a composition containing a binder resin and hollow silica particles. In particular, it is preferably composed of a cured product of a radiation curable composition containing these components. Hereinafter, a suitable composition will be described.

[0052] As the binder resin, from the viewpoint of improving the scratch resistance of the low refractive index layer 16, etc., radiation curable compounds typified by thermosetting compounds or ultraviolet curable compounds are preferred. From the viewpoint of the productivity of the antireflection film 10, etc., the binder resin is preferably in a form composed of an ultraviolet curable compound.

[0053] As the ultraviolet curable resin, monomers, oligomers, prepolymers, etc. having ultraviolet reactive reactive groups can be cited. As the ultraviolet reactive reactive groups, radical polymerization type reactive groups having an ethylenically unsaturated bond such as acryloyl, methacryloyl, allyl, vinyl, etc., cationic polymerization type reactive groups such as oxetanyl, etc. can be cited. Among them, acryloyl, methacryloyl, and oxetanyl are more preferred, and acryloyl and methacryloyl are particularly preferred. That is, it is particularly preferred to use (meth)acrylate compounds. The ultraviolet curable resin may be composed of a single one of the (meth)acrylates exemplified below, or may be composed of two or more of them.

[0054] As the (meth)acrylate compound, urethane (meth)acrylate, silicone (meth)acrylate, alkyl (meth)acrylate, aryl (meth)acrylate, etc. can be cited. The (meth)acrylate may be composed only of monofunctional (meth)acrylate, may be composed only of polyfunctional (meth)acrylate, or may be composed of a combination of monofunctional (meth)acrylate and polyfunctional (meth)acrylate. As the (meth)acrylate, polyfunctional (meth)acrylate is more preferably included.

[0055] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (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, 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, tricyclodecyl (meth)acrylate, dicyclopentyl (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 (meth)acrylate, ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, etc.

[0056] Examples of the polyfunctional (meth)acrylate include difunctional (meth)acrylate, trifunctional (meth)acrylate, tetrafunctional (meth)acrylate, etc. More specifically, examples include 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, 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, tripentaerythritol octa(meth)acrylate, etc.

[0057] (Meth)acrylate compounds may also contain a fluorine-containing (meth)acrylate having an acryloyloxy group.

[0058] The fluorine-containing (meth)acrylate may be composed only of a fluorine-containing monofunctional (meth)acrylate, only of a fluorine-containing polyfunctional (meth)acrylate, or a combination of a fluorine-containing monofunctional (meth)acrylate and a fluorine-containing polyfunctional (meth)acrylate. From the viewpoint of improving scratch resistance, a fluorine-containing polyfunctional (meth)acrylate is preferably included as the fluorine-containing (meth)acrylate.

[0059] Examples of the fluorine-containing monofunctional (meth)acrylate include 1-(meth)acryloyloxy-1-perfluoroalkylmethane, 1-(meth)acryloyloxy-2-perfluoroalkyl ethane, etc. The perfluoroalkyl group may be a linear, branched, or cyclic perfluoroalkyl group having 1 to 8 carbon atoms.

[0060] Preferred examples of the fluorine-containing polyfunctional (meth)acrylate include fluorine-containing difunctional (meth)acrylate, fluorine-containing trifunctional (meth)acrylate, and fluorine-containing tetrafunctional (meth)acrylate.

[0061] As the fluorine-containing difunctional (meth)acrylate, examples thereof include 1,2-bis(meth)acryloyloxy-3-perfluoroalkylbutane, 2-hydroxy-1H,1H,2H,3H,3H-perfluoroalkyl-2',2'-bis{(meth)acryloxymethyl}propionate, α,ω-bis(meth)acryloxymethyl perfluoroalkane, etc. The perfluoroalkyl group is preferably a linear, branched or cyclic perfluoroalkyl group having 1 to 11 carbon atoms, and the perfluoroalkane group is preferably a linear perfluoroalkane group having 1 to 11 carbon atoms. These fluorine-containing difunctional (meth)acrylates can be used alone or as a mixture when in use.

[0062] As an example of the fluorine-containing trifunctional (meth)acrylate, examples thereof include 2-(meth)acryloyloxy-1H,1H,2H,3H,3H-perfluoroalkyl-2',2'-bis{(meth)acryloxymethyl}propionate, etc. The perfluoroalkyl group is preferably a linear, branched or cyclic perfluoroalkyl group having 1 to 11 carbon atoms.

[0063] As an example of the fluorine-containing tetrafunctional (meth)acrylate, preferably α,β,ψ,ω-tetra{(meth)acryloyloxy}-αH,αH,βH,γH,γH,χH,χH,ψH,ωH,ωH-perfluoroalkane, etc. The perfluoroalkane group is preferably a linear perfluoroalkane group having 1 to 14 carbon atoms. When in use, the fluorine-containing tetrafunctional (meth)acrylate can be used alone or as a mixture.

[0064] When the fluorine-containing (meth)acrylate is contained in the low refractive index layer 16, the content of the fluorine-containing (meth)acrylate is preferably 30% by mass or more, more preferably 50% by mass or more, and may also be the total amount, relative to the total solid content of the binder resin. In this way, it is easy to lower the refractive index of the low refractive index layer 16 to obtain good antireflectivity.

[0065] When the fluorine-containing (meth)acrylate is contained in the low refractive index layer 16, the fluorine-containing (meth)acrylate is not specified in terms of the value of the surface free energy or the magnitudes of the respective components of the surface free energy, unlike the fluorine-containing (meth)acrylate contained in the antifouling layer 18 described later. A fluorine-containing (meth)acrylate having a large surface free energy is difficult to impart high water and oil repellency and the resulting high antifouling property. However, in the antireflection film 10 according to the present embodiment, the low refractive index layer 16 is not exposed on the outermost surface, and the antifouling layer 18 on the outermost surface ensures the antifouling property. Therefore, the low refractive index layer 16 does not need to exhibit high water and oil repellency. Instead, the fluorine-containing (meth)acrylate contained in the low refractive index layer 16 is preferably a fluorine-containing (meth)acrylate having a large surface free energy from the viewpoint of improving the adhesion of the antifouling layer 18 to the low refractive index layer 16. For example, the surface free energy of the fluorine-containing (meth)acrylate contained in the low refractive index layer 16 is preferably more than 60 mN / m. If the surface free energy is 80 mN / m or more, and further 90 mN / m or more, it is particularly preferred. In addition, the fluorine-containing (meth)acrylate contained in the low refractive index layer 16 preferably has a larger surface free energy (γ) and its polar component (γp) than the large polar component-containing fluorine-containing (meth)acrylate contained in the antifouling layer 18 described later.

[0066] The hollow silica particles are particles having an average particle diameter smaller than the average thickness d of the low refractive index layer 16 and substantially do not contribute to the formation of surface irregularities of the low refractive index layer 16. The hollow silica particles are particles having a cavity inside the particle, and the proportion of the cavity is 5% or more by volume. Hollow means a state having a shell structure or a porous structure. Among them, the shell structure is a structure composed of an outer shell and a cavity inside, and the porous structure is a structure having many cavities. Since the hollow silica particles have a hollow structure, the refractive index of the low refractive index layer 16 can be lowered and light reflection can be reduced. The shape of the hollow silica particles is not particularly limited, but spherical, spindle-shaped, egg-shaped, plate-shaped, cubic, amorphous, etc. are preferred. Among them, spherical, plate-shaped, cubic, etc. are particularly preferred.

[0067] In the hollow silica particles, the proportion of the cavity is preferably 10% or more and 80% or less by volume. When the proportion of the cavity is 10% or more by volume, the refractive index can be lowered and light reflection can be reduced. More preferably, it is 20% or more by volume, and further preferably 30% or more by volume. On the other hand, when the proportion of the cavity is 80% or less by volume, a decrease in the dispersibility of the hollow silica particles can be suppressed. More preferably, it is 60% or less by volume.

[0068] Although the average particle diameter of the hollow silica particles also depends on the thickness d of the low refractive index layer 16, it is preferably 5 nm or more and 100 nm or less. More preferably, it is 20 nm or more, and still more preferably, it is 40 nm or more. In addition, more preferably, it is 80 nm or less, and still more preferably, it is 70 nm or less. When the average particle diameter of the hollow silica particles is within these preferred ranges, excellent antireflection effects and transparency can be obtained in the low refractive index layer 16. The average particle diameter is the arithmetic mean based on volume obtained by the laser diffraction / scattering method in accordance with JIS Z8825. It includes not only the primary particle diameter but also the secondary particle diameter as aggregates of the particles.

[0069] The refractive index of the hollow silica particles is preferably in the range of 1.01 or more and 1.45 or less. More preferably, it is in the range of 1.15 or more and 1.38 or less, and still more preferably, it is in the range of 1.15 or more and 1.35 or less. When the refractive index of the hollow silica particles is within this range, excellent antireflection effects can be obtained.

[0070] The content of the hollow silica particles in the low refractive index layer 16 can be 6.0% by mass or more and 60% by mass or less with respect to 100% by mass of the solid components of the low refractive index layer 16. When the content of the hollow silica particles in the low refractive index layer 16 is 6.0% by mass or more with respect to 100% by mass of the solid components of the low refractive index layer 16, excellent antireflectivity can be obtained. In addition, from this viewpoint, the content of the hollow silica particles in the low refractive index layer 16 is more preferably 15% by mass or more, and still more preferably, it is 30% by mass or more with respect to 100% by mass of the solid components of the low refractive index layer 16. And when the content of the hollow silica particles in the low refractive index layer 16 is 60% by mass or less with respect to 100% by mass of the solid components of the low refractive index layer 16, the decrease in scratch resistance is suppressed. In addition, from this viewpoint, the content of the hollow silica particles in the low refractive index layer 16 is more preferably 55% by mass or less, and still more preferably, it is 50% by mass or less with respect to 100% by mass of the solid components of the low refractive index layer 16. In addition, the so-called solid components of the low refractive index layer 16 are components excluding components that are liquid at normal temperature and not immobilized by the binder resin in the low refractive index layer 16. As the solid components of the low refractive index layer 16, it includes hollow silica particles, binder resin, etc. It does not include oil components as additives or surfactants not immobilized by the binder resin.

[0071] In addition to containing hollow silica particles, the low refractive index layer 16 may also contain inorganic oxide particles. When the inorganic oxide particles are included in the low refractive index layer 16, convex portions are formed on the surface of the low refractive index layer 16. By forming convex portions on the surface of the low refractive index layer 16 from the inorganic oxide particles, the low refractive index layer 16 can have good scratch resistance.

[0072] The inorganic oxide particles can be solid particles or hollow particles. The inorganic oxide particles are preferably solid particles. Solid particles refer to particles that substantially do not have a cavity inside, and are particles in which the proportion of the cavity is less than 5% of the volume of the solid particles. Hollow particles refer to particles that have a cavity inside, and are particles in which the proportion of the cavity is 5% or more of the volume of the hollow particles. When the inorganic oxide particles are solid particles, the scratch resistance of the low refractive index layer 16 is improved, and the scratch resistance of the antireflection film 10 is improved. When the inorganic oxide particles are hollow particles, the refractive index of the low refractive index layer 16 can be made lower, and the reflection of light can be reduced. In the hollow particles, the proportion of the cavity is preferably 10% or more and 80% or less of the volume of the hollow particles. When the proportion of the cavity is 10% or more, the refractive index can be reduced and the reflection of light can be reduced. More preferably, it is 20% or more, and further preferably 30% or more. On the other hand, when the proportion of the cavity is 80% or less, the decrease in the dispersibility of the inorganic oxide particles can be suppressed. More preferably, it is 60% or less.

[0073] Examples of the inorganic oxide particles include metal oxide particles containing oxides of metals such as zirconium, silicon, aluminum, and calcium. They can be used alone as 1 type of inorganic oxide particle, or 2 or more types can be used in combination. Among them, from the viewpoints of low refractive index, excellent transparency, high hardness, etc., silica particles and alumina particles are preferred, and alumina particles are particularly preferred.

[0074] The shape of the inorganic oxide particles is not particularly limited, and can be spherical, needle-like, scaly, rod-like, fibrous, amorphous, etc. Among them, spherical shape is preferred.

[0075] In order to form convex portions on the surface of the low refractive index layer 16 with the inorganic oxide particles and obtain good scratch resistance, the difference (r - d) between the average particle diameter r of the inorganic oxide particles and the average thickness d of the low refractive index layer 16 can be 10 nm or more. The difference (r - d) is more preferably 15 nm or more, and further preferably 18 nm or more. On the other hand, from the viewpoints of suppressing the height of the formed convex portions and maintaining transparency, etc., the difference (r - d) is 300 nm or less. More preferably, it is 200 nm or less, and further preferably 100 nm or less.

[0076] Although the average particle diameter r of the inorganic oxide particles also depends on the thickness d of the low refractive index layer 16, it is preferably in the range of 60 nm or more and 400 nm or less. More preferably, it is 70 nm or more, and still more preferably, it is 90 nm or more. In addition, more preferably, it is 300 nm or less, and still more preferably, it is 200 nm or less. The average particle diameter r of the inorganic oxide particles is the arithmetic average based on volume obtained by the laser diffraction / scattering method in accordance with JIS Z8825, and includes not only the primary particle diameter but also the secondary particle diameter as aggregates of the particles.

[0077] The content of the inorganic oxide particles in the low refractive index layer 16 may be 0.1% by mass or more and 4.0% by mass or less with respect to 100% by mass of the solid components of the low refractive index layer 16. When the content of the inorganic oxide particles in the low refractive index layer 16 is 0.1% by mass or more with respect to 100% by mass of the solid components of the low refractive index layer 16, excellent scratch resistance can be obtained. In addition, from this viewpoint, the content of the inorganic oxide particles in the low refractive index layer 16 is more preferably 0.5% by mass or more, and still more preferably, it is 1.0% by mass or more with respect to 100% by mass of the solid components of the low refractive index layer 16. Further, when the content of the inorganic oxide particles in the low refractive index layer 16 is 4.0% by mass or less with respect to 100% by mass of the solid components of the low refractive index layer 16, high transparency can be obtained. In addition, from this viewpoint, the content of the inorganic oxide particles in the low refractive index layer 16 is more preferably 3.5% by mass or less, and still more preferably, it is 3.2% by mass or less with respect to 100% by mass of the solid components of the low refractive index layer 16.

[0078] Moreover, the total amount of the inorganic oxide particles and the hollow silica particles in the low refractive index layer 16 may be 10% by mass or more and 50% by mass or less with respect to 100% by mass of the solid content of the low refractive index layer 16. When the total amount of the inorganic oxide particles and the hollow silica particles in the low refractive index layer 16 is 10% by mass or more with respect to 100% by mass of the solid content of the low refractive index layer 16, excellent abrasion resistance can be obtained. Further, from this viewpoint, the total amount of the inorganic oxide particles and the hollow silica particles in the low refractive index layer 16 is more preferably 15% by mass or more, and still more preferably 20% by mass or more, with respect to 100% by mass of the solid content of the low refractive index layer 16. On the other hand, when the total amount of the inorganic oxide particles and the hollow silica particles in the low refractive index layer 16 is 50% by mass or less with respect to 100% by mass of the solid content of the low refractive index layer 16, the inorganic oxide particles and the hollow silica particles can be sufficiently retained in the low refractive index layer 16, so that excellent abrasion resistance can be obtained. Further, from this viewpoint, the total amount of the inorganic oxide particles and the hollow silica particles in the low refractive index layer 16 is more preferably 45% by mass or less, and still more preferably 40% by mass or less, with respect to 100% by mass of the solid content of the low refractive index layer 16.

[0079] The low refractive index layer 16 can be formed using a composition containing hollow silica particles, a binder resin, and further, if necessary, inorganic oxide particles. As described above, the binder resin is preferably a resin having a UV-reactive reactive group such as a resin containing a (meth)acrylate compound (UV-curable resin). When the binder resin has a UV-reactive reactive group, the abrasion resistance of the low refractive index layer 16 is improved, and the abrasion resistance of the antireflection film 10 is improved. The composition for forming the low refractive index layer 16 preferably further contains a photoinitiator when the binder resin has a UV-reactive reactive group. In the composition for forming the low refractive index layer 16, a solvent may be contained as needed. The binder resin of the low refractive index layer 16 may be composed only of a UV-curable resin, or may be composed of a combination of a UV-curable resin and a non-UV-curable resin. As the non-UV-curable resin, photoinitiator, and solvent, the chemical species specifically exemplified above as the substances that can be contained in the composition for forming the hard coat layer 14 can also be appropriately applied in the composition for forming the low refractive index layer 16, respectively.

[0080] Based on the total amount of the solid content of the composition for forming the low refractive index layer 16, the content of the photoinitiator is preferably in the range of 0.1% by mass or more and 10% by mass or less. More preferably, it is 1% by mass or more and 5% by mass or less.

[0081] In addition, in the low refractive index layer 16, additives and the like may be included as needed. Examples of such additives include dispersants, leveling agents, defoaming agents, thixotropic agents, antibacterial agents, flame retardants, slip agents, refractive index adjusters, and the like.

[0082] The average thickness d of the low refractive index layer 16 is preferably in the range of 60 to 160 nm, more preferably in the range of 70 to 140 nm, and still more preferably in the range of 80 to 120 nm. When within this range, the visual reflectance becomes good and the light reflection can be reduced. The thickness of the low refractive index layer 16 is the thickness of the relatively smooth portion in the portion where there are no irregularities caused by inorganic particles in the thickness direction.

[0083] The refractive index of the low refractive index layer 16 only needs to be lower than that of the hard coat layer 14 and is not particularly limited, but is preferably 1.26 or more and 1.50 or less. When the refractive index is 1.26 or more, the strength of the low refractive index layer 16 can be sufficient and good scratch resistance can be obtained. On the other hand, when the refractive index is 1.50 or less, the antireflection film 10 can be made to have a lower reflectance. From the above viewpoints, the refractive index of the low refractive index layer 16 is more preferably 1.28 or more and 1.40 or less, and still more preferably 1.30 or more and 1.37 or less.

[0084] (Antifouling layer)

[0085] In the antireflection film 10 according to this embodiment, an antifouling layer 18 is provided on the surface of the low refractive index layer 16. The antifouling layer 18 improves the antifouling property of the antireflection film 10.

[0086] The antifouling layer 18 is composed of a cured product of a composition containing a fluorine-containing (meth)acrylate. It is particularly preferably composed of a cured product of a radiation-curable composition containing a fluorine-containing (meth)acrylate, especially a UV-curable composition.

[0087] By forming the antifouling layer 18 from a cured product of a composition containing a fluorine-containing (meth)acrylate, the antifouling property and abrasion resistance of the antireflection film 10 having the antifouling layer 18 on its surface become excellent. Specific examples of the fluorine-containing (meth)acrylate include (meth)acrylates containing a perfluoropolyether group. The perfluoropolyether group refers to a group in which all the hydrogens in a polyether such as polyethylene glycol or polypropylene glycol are replaced by fluorine. For example, a fluoropolyether group having a repeating structure formed by any one of perfluoromethylene oxide (-CF2O-), perfluoroethylene oxide (-CF2CF2O-), perfluoropropylene oxide (-CF2CF2CF2O-), perfluoroisopropylidene oxide (-CF(CF3)CF2O-), or a combination of multiple ones of them can be cited. The number of repeating units of the above repeating structure is preferably 1 to 100. The fluorine-containing (meth)acrylate preferably has a polar moiety represented by a hydroxyl group at the end of the perfluoroether group or the like. Specific compounds include "KY-1203", "KY-1207", "KY-1211", "KY-1216", "KY-1240" manufactured by Shin-Etsu Chemical Co., Ltd., "MEGAFAC RS-75" manufactured by DIC Corporation, "OPTOOL DAC-HP", "OPTOOL DAC-100" manufactured by Daikin Industries, Ltd., "FTERGENT601AD", "FTERGENT 601ADH2" manufactured by Neos Co., Ltd.

[0088] In addition, the fluorine-containing (meth)acrylate may contain, as at least a part thereof, a substance having a urethane bond in its molecular structure. However, the content of the fluorine-containing (meth)acrylate having a urethane bond is preferably less than 15 parts by mass with respect to 100 parts by mass of the fluorine-containing (meth)acrylate not having a urethane bond. By suppressing the content of the fluorine-containing (meth)acrylate having a urethane bond to less than 15 parts by mass, the hardness of the antifouling layer 18 becomes high, and the antifouling layer 18 imparts particularly high abrasion resistance. The content is more preferably less than 10 parts by mass, and still more preferably less than 5 parts by mass. The fluorine-containing (meth)acrylate particularly preferably does not contain a fluorine-containing (meth)acrylate having a urethane bond.

[0089] In the antifouling layer 18, based on the total amount of the solid components of the antifouling layer 18, the content of the fluorine-containing (meth)acrylate is 90% by mass or more. Thereby, the effect of improving the antifouling property brought about by the fluorine-containing (meth)acrylate can be obtained to a relatively high degree. From the viewpoint of further enhancing the effect of improving the antifouling property, in the antifouling layer 18, if based on the total amount of the solid components of the antifouling layer 18, the content of the fluorine-containing (meth)acrylate is 92% by mass or more, it is more preferable. Further, if the inevitable components are excluded, it is more preferable that the entire amount of the resin components constituting the antifouling layer 18 is the fluorine-containing (meth)acrylate. In the antireflection film 10 according to the present embodiment, as will be described later, since the antifouling layer 18 contains a fluorine-containing (meth)acrylate having a high polar component γp of the surface free energy and exhibits high adhesion to the low refractive index layer 16, the improvement in adhesion to the low refractive index layer 16 and the resulting effect of improving the abrasion resistance can be sufficiently obtained. Therefore, there is no need to add a fluorine-free binder resin such as a fluorine-free (meth)acrylate compound for the purpose of obtaining these effects in the antifouling layer 18. Instead, by not adding a fluorine-free (meth)acrylate compound, the fluorine-containing (meth)acrylate can be contained at a high concentration accordingly, and high antifouling property can be easily obtained and high abrasion resistance can be easily obtained. In addition, the solid components of the antifouling layer 18 herein refer to components excluding those that are liquid at normal temperature and are not immobilized by the curable components in the antifouling layer 18. As the solid components of the antifouling layer 18, fluorine-containing (meth)acrylates and the like are included.

[0090] In the antireflection film 10 according to the present embodiment, the antifouling layer 18 contains, as at least a part of the fluorine-containing (meth)acrylates, a fluorine-containing (meth)acrylate having a polar component γp of the surface free energy of 18 mN / m or more (hereinafter, sometimes referred to as a large polar component fluorine-containing (meth)acrylate). And, the content (proportion in all the fluorine-containing (meth)acrylates) of the large polar component fluorine-containing (meth)acrylate in the solid components of the fluorine-containing (meth)acrylates contained in the antifouling layer 18 is 50% by mass or more.

[0091] The surface free energy refers to the energy of the molecules possessed by the surface of the solid itself and means the wettability to a liquid or another solid. The surface free energy of a certain substance can be divided into three components: a dispersion component (γd), a polar component (γp), and a hydrogen bond component (γh). The dispersion component (γd) represents the effect brought about by the dispersion force, the polar component (γp) represents the effect brought about by the dipole-dipole force, and the hydrogen bond component (γh) represents the effect brought about by the hydrogen bond force, and can be calculated based on the Kitaoka-Hata theory. The unit is represented by mN / m. Specifically, the surface free energy γ is represented by the following formula (1).

[0092] γ = γd + γp + γh (1)

[0093] In addition, in a state where a certain liquid is disposed on the surface of a certain solid, the surface free energy γ of the liquid L , the surface free energy γ of the solid s , and the relationship of the contact angle θ of the liquid are represented by the following formula (2). In formula (2), γd s , γp s , γh s and γd L , γp L , γh L respectively show the components of γd, γp, and γh for the liquid and the solid.

[0094] γ L (1 + cosθ) = 2(γd s ·γd L ) 1 / 2 + 2(γp s ·γp L ) 1 / 2 + 2(γh s ·γh L ) 1 / 2 (2)

[0095] Here, by using three kinds of liquids with known components (γd L , γp L , γh L ) of γ, measuring the respective contact angles θ on the surface of a certain solid, and solving the simultaneous equations, the components (γd L ) of the surface free energy of the solid as unknown parameters can be obtained. For the evaluation of the surface free energy of a single fluorinated (meth)acrylate, it is only necessary to form a layer after drying the fluorinated (meth)acrylate alone and perform the measurement on this layer. s , γp s , γh s )

[0096] The antifouling layer 18 of the antireflection film 10 according to this embodiment contains a large-polarity component fluorinated (meth)acrylate having a polar component γp of the surface free energy of 18 mN / m or more as at least a part of the fluorinated (meth)acrylates. Thus, excellent abrasion resistance can be obtained. It is considered that the reason is that the adhesion of the antifouling layer 18 to the underlying low-refractive-index layer 16 is improved by the large-polarity component fluorinated (meth)acrylate. A large polar component γp of the surface free energy of the fluorinated (meth)acrylate means that the fluorinated (meth)acrylate contains polar parts such as hydroxyl groups in the molecular structure, and it is speculated that the adhesion to the low-refractive-index layer 16 can be improved by the contribution of these polar parts. If the abrasion resistance is improved by the antifouling layer 18 containing the large-polarity component fluorinated (meth)acrylate, even if the surface of the antireflection film 10 is wiped with a cloth or a felt material, etc., abrasion marks (changes in the reflection characteristics at the friction part) or damage are not likely to occur.

[0097] From the viewpoint of further improving the effect of abrasion resistance, the polar component γp of the surface free energy of the large-polarity component fluorinated (meth)acrylate contained in the antifouling layer 18 is preferably 19 mN / m or more, more preferably 20 mN / m or more. On the other hand, the upper limit of γp is not particularly specified, but from the viewpoint of good antifouling property, it is preferably 35 mN / m or less, more preferably 30 mN / m or less, and further preferably 25 mN / m or less.

[0098] Moreover, by making the content of the large-polarity component fluorinated (meth)acrylate 50% by mass or more of the solid components of the fluorinated (meth)acrylates in the antifouling layer 18, the abrasion resistance of the antifouling layer 18 can be effectively improved. From the viewpoint of further improving this effect, in terms of the total amount of the solid components of the fluorinated (meth)acrylates in the antifouling layer 18, the content of the large-polarity component fluorinated (meth)acrylate is more preferably 55% by mass or more, and further preferably 60% by mass or more. It is particularly preferred that the entire amount of the fluorinated (meth)acrylates contained in the antifouling layer 18 is the large-polarity component fluorinated (meth)acrylate, excluding inevitable impurities.

[0099] The hydrogen bond component γh of the surface free energy of the large-polarity component fluorinated (meth)acrylate is not particularly limited, but is preferably 8 mN / m or less, more preferably 6 mN / m or less, and further preferably 3 mN / m or less. If γh is 8 mN / m or less, the antifouling effect of the antifouling layer 18 is good. On the other hand, the lower γh is, the more preferred it is, and the lower limit can be 0.

[0100] The dispersive component γd of the surface free energy of the fluorine-containing (meth)acrylate with a large polar component is not particularly limited, but is preferably 8 mN / m or more and 40 mN / m or less, more preferably 10 mN / m or more and 35 mN / m or less, and still more preferably 11 mN / m or more and 32 mN / m or less. If γd is within this range, it is easy to suppress the aggregation of the fluorine-containing (meth)acrylate and obtain a uniform coating film.

[0101] The surface free energy γ of the fluorine-containing (meth)acrylate with a large polar component is not particularly limited, but is preferably 26 mN / m or more and 60 mN / m or less, more preferably 28 mN / m or more and 50 mN / m or less, and still more preferably 30 mN / m or more and 40 mN / m or less. If γ is within these ranges, the antifouling property of the antifouling layer 18 can be made good.

[0102] The antifouling layer 18 can be formed using a composition containing a fluorine-containing (meth)acrylate. It is only necessary to cure it after arranging the composition for forming the antifouling layer 18 in a layer on the surface of the low refractive index layer 16. When the antifouling layer 18 is formed as a cured product of a composition having ultraviolet curability, the composition for forming the antifouling layer 18 preferably further contains a photoinitiator. In addition, a solvent may be contained as needed.

[0103] As the photoinitiator and the solvent, the chemical species specifically exemplified as the substances that can be contained in the composition for forming the hard coat layer 14 can also be appropriately applied to the composition for forming the antifouling layer 18, respectively. The content of the photoinitiator is preferably in the range of 0.1% by mass or more and 15% by mass or less based on the total amount of the solid components of the composition for forming the antifouling layer 18. It is more preferably 3% by mass or more and 10% by mass or less.

[0104] In addition, in the antifouling layer 18, additives and the like may be contained 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 adjusters, etc. However, from the viewpoint of improving the smoothness of the surface of the antifouling layer 18, the antifouling layer 18 preferably does not contain solid particles represented by hollow silica particles or metal oxide particles. Even when the antifouling layer 18 contains solid particles, it is only necessary to suppress the particle diameter of the solid particles to 10 nm or less and the content of the solid particles to 1% by mass or less based on 100% by mass of the solid components of the antifouling layer 18.

[0105] The thickness of the antifouling layer 18 is preferably 1 nm or more. In this case, the effect of improving the antifouling property brought by the antifouling layer 18 can be obtained relatively highly. More preferably, the thickness of the antifouling layer 18 is 3 nm or more, and further can be 5 nm or more. On the other hand, the thickness of the antifouling layer 18 is preferably 20 nm or less. In this case, the antireflection property and abrasion resistance of the antireflection film 10 can be ensured relatively highly. More preferably, the thickness of the antifouling layer 18 is 15 nm or less, and further can be 10 nm or less.

[0106] The refractive index of the antifouling layer 18 is preferably 1.6 or less. If the refractive index is 1.6 or less, the antireflection property of the antireflection film 10 can be ensured relatively highly. More preferably, the refractive index of the antifouling layer 18 is 1.55 or less, and further can be 1.50 or less. On the other hand, as long as the thickness of the antifouling layer 18 is within the above range, the refractive index of the antifouling layer 18 is not particularly limited, but is preferably 1.3 or more, and more preferably 1.35 or more.

[0107] (Method for manufacturing an antireflection film)

[0108] When manufacturing the antireflection film 10, it is only necessary to sequentially form the hard coat 14, the low refractive index layer 16, and the antifouling layer 18. When forming each layer, apply the composition for forming each layer, and after drying if necessary, cure it by a method corresponding to the curability of the composition, such as irradiation with ionizing radiation represented by ultraviolet rays. After forming a certain layer, apply the composition for forming the next layer, and after drying if necessary, cure the composition. By repeating this process in sequence, a laminated structure of the hard coat 14, the low refractive index layer 16, and the antifouling layer 18 can be formed to manufacture the antireflection film 10.

[0109] In the application of the composition for forming each layer, a wet method can be suitably used. Specifically, for example, various coating methods such as reverse gravure coating method, direct gravure coating method, die coating method, bar coating method, wire bar coating method, roll coating method, spin coating method, dip coating method, spray coating method, knife coating method, kiss coat method, etc., or various printing methods such as inkjet method, offset printing, screen printing, flexographic printing, etc. can be used.

[0110] The drying process for each layer only needs to remove the solvent and the like used in the coating liquid, and there is no particular limitation, but it is preferably carried out at a temperature of 50 to 150 °C for about 10 seconds to 180 seconds.

[0111] In the ultraviolet irradiation for each layer, a high-pressure mercury lamp, an electrodeless (microwave type) lamp, a xenon lamp, a metal halide lamp, or any other ultraviolet irradiation device can be used. If necessary, the ultraviolet irradiation can also be carried out in an inert gas atmosphere such as nitrogen. The ultraviolet irradiation amount is not particularly limited, but is preferably 50 to 800 mJ / cm2 , more preferably 100 to 300 mJ / cm 2 .

[0112] When forming the hard coat layer 14 on the surface of the substrate film 12, in order to improve the adhesion between the substrate film 12 and the hard coat layer 14, the surface of the substrate film 12 may be subjected to surface treatment before coating. Examples of the surface treatment include corona treatment, plasma treatment, hot air treatment, ozone treatment, ultraviolet treatment, and the like.

[0113] In the antireflection film 10, a primer layer having an effect of improving adhesion, such as a layer made of a fluorine-free (meth)acrylate resin, may be formed on the surface of the low refractive index layer 16, and then the antifouling layer 18 may be formed. However, since the antifouling layer 18 has high adhesion to the low refractive index layer 16 by containing a fluorine-containing (meth)acrylate having a large polar component in a predetermined amount or more, it is not necessary to provide a primer layer for the purpose of improving the adhesion of the antifouling layer 18 and the resulting improvement in abrasion resistance. In terms of simplifying the configuration of the antireflection film 10, it is preferable not to provide a primer layer.

[0114] (Properties of the antireflection film)

[0115] The antireflection film 10 having the above configuration includes a substrate film 12, a hard coat layer 14 formed on the surface of the substrate film 12, a low refractive index layer 16 formed on the surface of the hard coat layer 14, and an antifouling layer 18 formed on the surface of the low refractive index layer 16. The antifouling layer 18 is composed of a cured product of a composition containing a fluorine-containing (meth)acrylate. Based on the total solid content of the antifouling layer 18, the content of the fluorine-containing (meth)acrylate in the antifouling layer 18 is 90% by mass or more, and 50% by mass or more of the solid components of the fluorine-containing (meth)acrylate contained in the antifouling layer are fluorine-containing (meth)acrylates having a surface free energy polar component γp of 18 mN / m or more. Therefore, it has excellent antireflection properties and antifouling properties, and is not easily scratched or damaged even after repeated wiping, and has high abrasion resistance.

[0116] Since the antireflection film 10 has high antifouling properties, dirt such as fingerprints does not easily adhere to the surface of the antireflection film 10, and even if it adheres, it can be easily removed. The antireflection film 10 according to the present embodiment is particularly excellent in fingerprint wipeability. In the antireflection film 10 according to the present embodiment, it is considered that the antifouling layer 18 containing 90% by mass or more of fluorine-containing (meth)acrylate based on the total solid content contributes to high antifouling properties. In addition, it is considered that the high adhesion between the low refractive index layer 16 and the antifouling layer 18 brought about by the fluorine-containing (meth)acrylate having a large polar component with a surface free energy polar component γp of 18 mN / m or more in the solid component of the fluorine-containing (meth)acrylate contributes to high abrasion resistance. The antireflection film 10 according to the present embodiment has high scratch resistance and abrasion resistance in addition to high antireflection properties and antifouling properties, and is therefore particularly suitable for applications that are frequently touched by fingers, such as being disposed on the surface of a touch panel.

[0117] The lower the visual reflectance in the antireflection film 10, the more preferable it is, more preferably 2.0% or less, further preferably 1.5% or less, and particularly preferably 1.0% or less. If the visual reflectance is 2.0% or less, it can be regarded that the antireflection film 10 has sufficiently high antireflection properties.

[0118] As an index of high antifouling properties, the water contact angle of the antireflection film 10 according to the present embodiment is preferably 100° or more, further preferably 105° or more. In addition, the oleic acid contact angle is preferably 73° or more, further preferably 75° or more. Moreover, the oleic acid sliding angle is preferably 25° or less, further preferably 20° or less. Oleic acid is a substance that mimics sebum. The larger the oleic acid contact angle, the less likely it is that organic dirt such as sebum adheres to the antireflection film 10. In addition, the smaller the oleic acid sliding angle, the easier it is to remove dirt such as sebum even if it adheres, and it is also easy to maintain the antifouling properties brought about by the antifouling layer 18 after friction with a cloth or the like to remove the adhered dirt. In addition, the surface free energy of the surface of the antireflection film 10 (the surface in the state where each constituent layer is laminated and cured) is preferably 30 mN / m or less, further preferably 20 mN / m or less, and particularly preferably 15 mN / m or less. In this way, high water and oil repellency and antifouling properties can be obtained on the surface of the antireflection film 10.

[0119] <Other antireflection films>

[0120] The antireflection film according to the present invention only needs to have a hard coat 14, a low refractive index layer 16, and an antifouling layer 18 laminated in this order on the surface of the base film 12 as described above and the antifouling layer 18 has a specified composition, and is not limited to the configuration of the antireflection film 10 according to the above first embodiment. Hereinafter, other embodiments of the antireflection film according to the present invention will be illustrated.

[0121] (Second Embodiment)

[0122] Figure 2 The antireflection film 20 according to the second embodiment is shown. The antireflection film 20 according to the second embodiment has: a substrate film 12; a hard coat 14 formed on the surface of the substrate film 12; a high refractive index layer 15 formed on the surface of the hard coat 14; a low refractive index layer 16 formed on the surface of the high refractive index layer 15; and an antifouling layer 18 formed on the surface of the low refractive index layer 16.

[0123] The antireflection film 20 according to the second embodiment is different from the antireflection film 10 according to the first embodiment in that a high refractive index layer 15 is provided between the hard coat 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 for the same configuration, its description is omitted.

[0124] The high refractive index layer 15 is a layer having a refractive index higher than that of the hard coat 14 and the low refractive index layer 16. By providing the high refractive index layer 15 between the hard coat 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. More preferably, it is 1.60 or more and 1.70 or less.

[0125] There is no particular limitation on the constituent material of the high refractive index layer 15, as long as a known material used for antireflection films or the like in the past is used in such a manner that a predetermined refractive index can be obtained. For example, it is sufficient to appropriately select from the materials described above as the materials that can be used in the hard coat 14 or the low refractive index 16. The refractive index of the high refractive index layer 15 can be adjusted by the selection of the binder resin, inorganic oxide particles, resin particles, the blending amount, etc. For example, by adding inorganic oxide particles such as titanium oxide particles in a sufficient amount, a high refractive index layer 15 having a refractive index higher than that of the low refractive index layer 16 can be formed.

[0126] The average thickness of the high refractive index layer 15 varies depending on the setting of the refractive index, but for example, by setting it to 50 nm or more and 200 nm or less, the antireflection function can be further improved. As the high refractive index layer 15, two or more layers having different refractive indices from each other may be laminated.

[0127] (Third Embodiment)

[0128] Figure 3FIG. 0 shows an antireflection film 30 according to the third embodiment. The antireflection film 30 according to the third embodiment has: a substrate film 12; a hard coat 14 formed on one surface of the substrate film 12; a low refractive index layer 16 formed on the surface of the hard coat 14; and an antifouling layer 18 formed on the surface of the low refractive index layer 16. Further, a transparent adhesive layer 22 is provided on the other surface of the substrate film 12. 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 the antireflection film 30 is used and is peeled off from the transparent adhesive layer 22 when the antireflection film 30 is used.

[0129] The antireflection film 30 according to the third embodiment is different from the antireflection film 10 according to the first embodiment in that a transparent adhesive layer 22 is provided on the other surface of the substrate film 12, and the rest is the same as the antireflection film 10 according to the first embodiment. For the same configuration, the description thereof is omitted.

[0130] The transparent adhesive layer 22 is used to attach the antireflection film 30 to the surface of a display or the like with good adhesion. Further, by having the transparent adhesive layer 22, the antireflection film 30 has an effect of preventing the glass of a display or the like from flying. That is, the antireflection film 30 also functions as an anti-scattering film.

[0131] The adhesive composition for forming the transparent adhesive layer 22 can contain known adhesive resins such as acrylic adhesives, silicone adhesives, and urethane adhesives. Among them, from the viewpoints of optical transparency and heat resistance, an acrylic adhesive is preferred. In order to improve the cohesion of the transparent adhesive layer 22, it is preferred that the adhesive composition contains a crosslinking agent. Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and chelate-based crosslinking agents.

[0132] The adhesive composition may also contain additives as needed. Examples of the additives include known additives such as plasticizers, silane coupling agents, surfactants, antioxidants, fillers, curing accelerators, and curing retarders. Further, from the viewpoints of productivity and the like, it can be diluted with an organic solvent.

[0133] The thickness of the transparent adhesive layer 22 is not particularly limited, but is preferably in 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.

[0134] The transparent adhesive layer 22 can be formed by the following methods, etc.: a method of directly applying an adhesive composition on the other surface of the substrate film 12 to form a transparent adhesive layer; a method of applying an adhesive composition on the surface of the release film 24 to form a transparent adhesive layer and then transferring it to the other surface of the substrate film 12; and a method of applying an adhesive composition on the surface of the first release film to form a transparent adhesive layer, then laminating the second release film, peeling off any one of the release films and transferring it to the other surface of the substrate film 12.

[0135] From the viewpoint of the effect of preventing glass scattering, the adhesive force of the transparent adhesive layer 22 to glass is preferably 4 N / 25 mm or more. More preferably, it is 6 N / 25 mm or more, and further preferably, it is 10 N / 25 mm or more.

[0136] (Fourth Embodiment)

[0137] Figure 4 The antireflection film 40 according to the fourth embodiment is shown. The antireflection film 40 according to the fourth embodiment has: a substrate film 12; a hard coat 14 formed on one surface of the substrate film 12; a low refractive index layer 16 formed on the surface of the hard coat 14; an antifouling layer 18 formed on the surface of the low refractive index layer 16; and a protective film 28 disposed on the surface of the antifouling layer 18 with an adhesive layer 26 interposed therebetween. In addition, a transparent adhesive layer 22 is provided on the other surface of the substrate film 12. A release film 24 is disposed on the surface of the transparent adhesive layer 22 as needed.

[0138] The antireflection film 40 according to the fourth embodiment is different from the antireflection film 30 according to the third embodiment in that a protective film 28 is provided on the surface of the antifouling layer 18 with an adhesive layer 26 interposed therebetween. Except for this, it is the same as the antireflection film 30 according to the third embodiment, and the description of the same configuration is omitted.

[0139] The protective film 28 can suppress surface damage of the antifouling layer 18, for example, when performing continuous processing such as a roll pressing process or when laminating the antireflection film 40 such as to a display. The protective film 28 is attached to the surface of the antifouling layer 18 via the adhesive layer 26. The protective film 28 is peeled off from the surface of the antifouling layer 18 together with the adhesive layer 26 after processing of the antireflection film 40 and the like. Therefore, regarding the adhesive layer 26, the adhesive force between the protective film 28 and the adhesive layer 26 is stronger than the adhesive force between the antifouling layer 18 and the adhesive layer 26, and is adjusted to an adhesive force that allows interfacial peeling between the antifouling layer 18 and the adhesive layer 26.

[0140] The material constituting the protective film 28 can be appropriately selected from materials such as those exemplified as the material constituting the substrate film 12. The thickness of the protective film 28 is not particularly limited, but can be in the range of 2 μm or more and 500 μm or less, or in the range of 2 μm or more and 200 μm or less.

[0141] As the adhesive layer 26, the adhesive layer described in International Publication No. 2021 / 020504 applied by the applicant can be suitably applied. The adhesive forming the adhesive layer 26 is not particularly limited, and an acrylic adhesive, a silicone adhesive, a urethane adhesive, etc. can be suitably used. In particular, an acrylic adhesive is suitable because of its excellent transparency and heat resistance. The acrylic adhesive is preferably formed from an adhesive composition containing a (meth)acrylic polymer and a crosslinking agent.

[0142] The (meth)acrylic polymer is a homopolymer or copolymer of (meth)acrylic monomers. Examples of the (meth)acrylic monomers include alkyl-containing (meth)acrylic monomers, carboxyl-containing (meth)acrylic monomers, hydroxyl-containing (meth)acrylic monomers, etc.

[0143] Examples of the crosslinking agent 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, melamine-based crosslinking agents, etc. The crosslinking agent can be used alone or in combination of two or more.

[0144] In addition to the (meth)acrylic polymer and the crosslinking agent, the adhesive composition may further contain other additives. Examples of the other additives include crosslinking accelerators, crosslinking retarders, resins imparting adhesiveness (tackifiers), antistatic agents, silane coupling agents, plasticizers, release aids, pigments, dyes, wetting agents, thickeners, ultraviolet absorbers, preservatives, antioxidants, metal deactivators, alkylating agents, flame retardants, etc. These additives are appropriately selected and used according to the use or purpose of use of the adhesive.

[0145] 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. More preferably, it is 2 μm or more and 7 μm or less.

[0146] The embodiments of the present invention have been described above, but the present invention is not limited by any of the above embodiments, and various changes can be made without departing from the gist of the present invention.

[0147] For example, in the above embodiment, it is described that the surface of the base film 12 can be surface-treated, but instead of the surface treatment, a configuration in which an easy-to-bond layer is provided on the surface of the base film 12 can be adopted.

[0148] And, the transparent adhesive layer 22 and the release film 24 in the above-described third embodiment are shown in the form of being added to the antireflection film 10 of the first embodiment as shown in Figure 3 shown, but may also be added to Figure 1 shown in the form of the first embodiment of the antireflection film 10 shown, but may also be added toFigure 2 The form of the antireflection film 20 of the second embodiment shown. In addition, the adhesive layer 26 and the protective film 28 in the fourth embodiment above are as Figure 4 shown in the form added to Figure 3 the antireflection film 30 of the third embodiment shown, but may also be in the form added to Figure 1 the antireflection film 10 of the first embodiment shown or Figure 2 the antireflection film 20 of the second embodiment shown.

[0149] Also, on the surface of the base film 12, various functional layers such as a gas barrier improvement layer, an antistatic layer, and an oligomer block layer can be provided in advance before forming each layer. As the antistatic layer, the antistatic layer described in International Publication No. 2021 / 020504 can be suitably applied.

[0150] Examples

[0151] Hereinafter, the present invention will be described in detail using examples and comparative examples. Hereinafter, unless otherwise specified, the production and evaluation of the samples are carried out at room temperature and in the air.

[0152] [Evaluation of each component of surface free energy]

[0153] First, for the fluorine-containing compound used for forming the antifouling layer and the binder resin used for forming the low refractive index layer in each example and comparative example, three components (γd, γp, γh) of the surface free energy were evaluated.

[0154] The following listed fluorine-containing compounds 1 to 3 and binder resin 1 were each applied to a polyethylene terephthalate film "Lumirror U403" (manufactured by Toray, thickness 100 μm) using a wire bar so that the dried thickness became 0.5 μm, and dried at 80 °C for 180 seconds to obtain samples for surface free energy measurement.

[0155] For the obtained measurement samples, using a contact angle meter (manufactured by Kyowa Interface Science, DropMaster DMo-502), 4 μL of droplets were dropped, and water ((γd L , γp L , γh L ) = (29.1, 1.3, 42.4)), diiodomethane ((γd L , γp L , γh L ) = (46.8, 4.0, 0)) and ethylene glycol ((γd L , γp L , γh L) = (30.1, 0, 17.6)). The three components (γd, γp, γh) of the surface free energy of each fluorine-containing compound were calculated from the contact angles of water, diiodomethane, and ethylene glycol according to equations (1) to (2).

[0156] The objects to be evaluated and the materials used for the production of the antifouling layers in each of the following specimens are as follows. Fluorine-containing compounds 1 to 3 are used for the formation of the antifouling layer, and binder resin 1 is used for the formation of the low refractive index layer.

[0157] · Fluorine-containing compound 1: “KY-1203” manufactured by Shin-Etsu Chemical Co., Ltd., a (meth)acrylate containing a perfluoropolyether group, methyl ethyl ketone, solid content concentration 20% by mass

[0158] · Fluorine-containing compound 2: “KY-1211” manufactured by Shin-Etsu Chemical Co., Ltd., a (meth)acrylate containing a perfluoropolyether group, methyl ethyl ketone, solid content concentration 20% by mass

[0159] · Fluorine-containing compound 3: “KY-1216” manufactured by Shin-Etsu Chemical Co., Ltd., a (meth)acrylate containing a perfluoropolyether group, methyl ethyl ketone, solid content concentration 20% by mass

[0160] · Binder resin 1: A fluorine-containing binder resin prepared by the method described below

[0161] In Table 1, the evaluation results are shown. In the table, the surface free energy (γ) calculated by equation (1) is also shown.

[0162] [Table 1]

[0163]

[0164] According to Table 1, the polar component γp of the surface free energy of fluorine-containing compound 1 is 18 mN / m or more. On the other hand, the polar components γp of the surface free energies of fluorine-containing compounds 2 and 3 are less than 18 mN / m. Compared with fluorine-containing compounds 1 to 3, binder resin 1 has a larger surface free energy γ and its polar component γp.

[0165] [Production of Specimens]

[0166] Next, as specimens to be evaluated, antireflection films related to Examples 1 to 3 and Comparative Examples 1 to 5 were produced.

[0167] <Preparation of Hard Coating-Forming Composition>

[0168] A solvent (ethyl acetate, propylene glycol monomethyl ether) was added to the ultraviolet curable resin composition "LIODURAS LAS-13030NL" (manufactured by Toyochem, urethane acrylate resin, photopolymerization initiator, solvent (ethyl acetate), solid content concentration 50% by mass) so that the solid content concentration became 45% by mass, to prepare a hard coat layer forming composition.

[0169] <Preparation of high refractive index layer-forming composition>

[0170] The following components were mixed at the ratios described above, and isopropyl alcohol was further added so that the solid content concentration became 7% by mass to prepare a composition for forming a high refractive index layer.

[0171] Ultraviolet curable resin composition: "Ultraviolet UV-7600B" manufactured by Mitsubishi Chemical, urethane acrylate resin, solid content concentration 100% to 54% by mass

[0172] Zinc antimonate fine particle dispersion: "CELNAX CX-Z603M-F2" manufactured by Nissan Chemical, zinc antimonate fine particles, solvent (methanol), solid content concentration 60 mass% to 44 mass%,

[0173] · Photopolymerization initiator: "Omnirad 184" manufactured by IGM Resins BV, 1-hydroxycyclohexyl phenyl ketone - 3% by mass

[0174] <Preparation of Composition for Forming Low Refractive Index Layer>

[0175] (Preparation of Binder Resin 1)

[0176] In a four-necked flask, 104 parts by mass of perfluoro-(1,1,9,9-tetrahydro-2,5-bisfluoromethyl-3,6-dioxinol) and 11 parts by mass of 8% perfluorohexane solution of bis(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptanoyl) peroxide were added. Then, after nitrogen substitution in the hollow part of the flask, the mixture was stirred at 20°C for 24 hours under a nitrogen stream to obtain a high-viscosity solid. The solid obtained by dissolving it in ether was injected into perfluorohexane, separated, and vacuum dried to obtain a colorless and transparent polymer as a fluorinated allyl ether polymer containing a hydroxyl group.

[0177] pass 19 F-NMR (nuclear magnetic resonance spectroscopy), 1The polymer was analyzed by H-NMR and IR (infrared absorption spectrum), and as a result, it was found to be a fluoropolymer having a hydroxyl group at the end of the side chain composed of structural units of a colorless and transparent polymer which is a fluorinated allyl ether polymer containing a hydroxyl group. The number average molecular weight determined by GPC (gel permeation chromatography) was 72,000, and the weight average molecular weight was 118,000.

[0178] 5 parts by mass of the obtained fluorinated allyl ether polymer containing a hydroxyl group, 43 parts by mass of methyl ethyl ketone (MEK), and 1 part by mass of pyridine were placed in a four-necked flask and cooled to 5°C or lower. Then, while stirring under a nitrogen stream, a substance obtained by dissolving 1 part by mass of fluoro-α-fluoropropenoate in 9 parts by mass of MEK was added dropwise over 10 minutes. Thus, a solution of binder resin 1 as a fluorinated compound having a polymerizable double bond was obtained.

[0179] (Preparation of the composition for forming a low refractive index layer)

[0180] The above binder resin 1, hollow silica particles, a fluorinated compound different from binder resin 1 (only in Comparative Example 4), and a photopolymerization initiator were mixed so as to have the blending composition (mass% in all solid components) shown in Table 2, and adjusted to the solid component concentration shown in Table 2 using isopropyl alcohol, whereby a composition for forming a low refractive index layer was prepared.

[0181] The materials used as the materials for the composition for forming a low refractive index layer are as follows.

[0182] · Binder resin: the above binder resin 1

[0183] · Hollow silica particles - "THRULYA 4320" manufactured by Nisshin Catalytic Chemical Industries Co., Ltd., average particle size: 60 nm, solvent: MIBK, solid component concentration: 20 mass%

[0184] · Photopolymerization initiator: "Omnirad 127" manufactured by IGM Resins B.V., 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, solid component concentration 100 mass%

[0185] · Fluorinated compound: the above "KY-1203"

[0186] <Preparation of the composition for forming an antifouling layer>

[0187] The fluorine-containing compounds 1 to 3, a binder resin (the above-mentioned "Violet UV-7600B"; only in Comparative Example 3), and a photoinitiator (the above-mentioned "Omnirad 127") were blended so as to have the blend composition (mass% in all solid components) shown in Table 2, and the solid component concentration shown in Table 2 was adjusted using a solvent (MEK / PGM = 1 / 3), whereby a composition for forming an antifouling layer was prepared.

[0188] <Fabrication of Hard Coating>

[0189] For each of Examples 1 to 3 and Comparative Examples 1 to 5, a hard coating-forming composition was applied to a substrate film ("TG60UL" manufactured by Fujifilm, cellulose triacetate film, thickness 60 μm) using a wire bar, dried at 80°C for 60 seconds, and then irradiated with ultraviolet light having a light amount of 200 mJ / cm 2 to form a hard coating. The film thickness is shown in Table 2.

[0190] <Fabrication of High Refractive Index Layer>

[0191] For each of Examples 1 to 3 and Comparative Examples 1 to 5, a high refractive index layer-forming composition was applied to the surface of the hard coating using a #3 wire bar, dried at 80°C for 60 seconds, and then irradiated with ultraviolet light having a light amount of 200 mJ / cm 2 in a nitrogen atmosphere to form a high refractive index layer (film thickness 160 nm).

[0192] <Fabrication of Low Refractive Index Layer>

[0193] For each of Examples 1 to 3 and Comparative Examples 1 to 5, a low refractive index layer-forming composition was applied to the surface of the high refractive index layer using a #3 wire bar, dried at 100°C for 60 seconds, and then irradiated with ultraviolet light having a light amount of 200 mJ / cm 2 in a nitrogen atmosphere to form a low refractive index layer. The film thickness is shown in Table 2.

[0194] <Fabrication of Antifouling Layer>

[0195] For each of Examples 1 to 3 and Comparative Examples 1 to 3, an antifouling layer-forming composition 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 irradiated with ultraviolet light having a light amount of 200 mJ / cm 2 in a nitrogen atmosphere to form an antifouling layer. The film thickness is shown in Table 2. For Comparative Examples 4 and 5, no antifouling layer was formed.

[0196] Based on the above, antireflection films related to Examples 1 to 3 and Comparative Examples 1 to 5 were fabricated.

[0197] [Evaluation Method]

[0198] (Thickness and Refractive Index of Each Layer)

[0199] For each sample, the thickness and refractive index of the hard coat layer, high refractive index layer, low refractive index layer, and antifouling layer were evaluated. At this time, each time a layer was formed, the reflectance spectroscopic spectrum in the wavelength region of 380 to 780 nm obtained using a microspectrophotometer for film thickness measurement ("OPTM-F1" manufactured by Otsuka Electronics Co., Ltd.) and the theoretical spectrum derived from the Fresnel formula were curve-fitted by the least squares method, and thus the thickness of each layer and the refractive index at a wavelength of 589.3 nm were calculated.

[0200] (Water Contact Angle and Oleic Acid Contact Angle)

[0201] The water contact angle and oleic acid contact angle of the antireflection film were measured using a contact angle meter (DropMaster DMo-502 manufactured by Kyowa Interface Science Co., Ltd.). Specifically, in an atmosphere at room temperature of 23°C and a relative humidity of 50%, 4 μL of pure water and oleic acid were respectively dropped onto the surface of the antifouling layer, and the water contact angle and oleic acid contact angle 30 seconds after dropping were measured. If the water contact angle is 100° or more and the oleic acid contact angle is 73° or more, it can be regarded as having high antifouling properties.

[0202] (Oleic Acid Sliding Angle)

[0203] The oleic acid sliding angle of the antireflection film was measured using a contact angle meter (DropMaster DMo-502 manufactured by Kyowa Interface Science Co., Ltd.). Specifically, in an atmosphere at room temperature of 23°C and a relative humidity of 50%, 5 μL of oleic acid was dropped onto the surface of the antifouling layer, and it was tilted from the horizontal (0°) state at a rate of 1° per second to 90°, and the tilt angle when the droplet started to slide was set as the oleic acid sliding angle. If the oleic acid sliding angle is 25° or less, it can be regarded as having high antifouling properties.

[0204] (Surface Free Energy)

[0205] For each sample, the surface free energy was evaluated. The evaluation was carried out by the same method as the method used to obtain the evaluation results in Table 1 in the item of "Evaluation of Each Component of Surface Free Energy" above. However, the evaluation in Table 1 was performed on the coating film after drying and before curing, while on the other hand, here, as described in the item of "Production of Samples" above, the evaluation was performed on the sample after laminating each layer, drying, and curing by ultraviolet irradiation.

[0206] (Visual Reflectance)

[0207] The back surface (the surface on the side opposite to the antifouling layer) of the produced antireflection film was polished rough with #400 sandpaper and entirely coated with black paint. Then, using an ultraviolet-visible-near-infrared spectrophotometer ("UV-3600" manufactured by Shimadzu Corporation), the 5° specular reflectance of the surface of the antifouling layer at wavelengths from 380 nm to 780 nm was measured, and the visual reflectance was calculated by multiplying the measured value by the relative visibility value. If the visual reflectance is 2.0% or less, it can be considered that the antireflection property is sufficient.

[0208] (Abrasion resistance)

[0209] For each specimen, the abrasion resistance was evaluated. At this time, using a flat abrasion tester ("DAS-400" manufactured by Dainichi Kagaku Seiki Co., Ltd.), a felt rod (manufactured by TABER, abrasive rod H1 (Felt), diameter 9 mm) was placed on the surface of the antireflection film of each specimen and the specimen was moved back and forth. The stroke length of the test bench was set to 50 mm, the reciprocating speed of the test bench was set to 25 reciprocations per minute, and the applied load was set to 5.0 N. The antireflection film after 5000 reciprocation tests was visually observed, and the abrasion resistance was evaluated according to the following criteria. Here, a wear mark refers to an area that does not cause physical damage to the specimen surface but looks different from the surrounding area due to a change in optical properties.

[0210] A: No wear marks or scratches are visible at all, and the abrasion resistance is very high

[0211] B: There are slight wear marks and / or scratches less than 10 mm in length, and the abrasion resistance is such that there are no problems in actual use

[0212] C: There are significant wear marks or scratches 10 mm or more in length, and the abrasion resistance is low (Antifouling property)

[0213] For each specimen, as an evaluation of the antifouling property, the fingerprint wipeability was evaluated.

[0214] A commercially available artificial fingerprint solution (manufactured by Iseku, artificial sweat method A (sweat tester method)) was taken onto a finger and smeared on the finger, and then the finger was pressed onto the surface of the antireflection film to attach fingerprints. Then, the antireflection film was placed on black paper, and using a polyester wiping material (manufactured by As One, ASPURE Super Wiper (Econo)), while visually observing, the fingerprints attached to the surface of the antireflection film were wiped, and the evaluation was carried out according to the following criteria.

[0215] A: It is possible to wipe until the artificial fingerprint solution is no longer visible within 5 reciprocations, and the antifouling property is very high

[0216] B: It can wipe until the fingerprint liquid of the human mouth is invisible within more than 5 round trips and within 10 round trips, and has stain resistance that is not problematic in actual use.

[0217] C: It cannot wipe off the fingerprint liquid of the human mouth even after 10 round trips, and has low stain resistance.

[0218] <Evaluation results>

[0219] In Table 2, regarding Examples 1 to 3 and Comparative Examples 1 to 5, the evaluation results are shown together with the component compositions of the low refractive index layer and the antifouling layer (unit: mass% in all solid components of each layer) and the layer structure of the antireflection film.

[0220] [Table 2]

[0221]

[0222] As shown in Table 2, in Examples 1 to 3, the antifouling layer formed on the surface of the low refractive index layer is composed of a cured product of a composition containing a fluorinated (meth)acrylate, and an antifouling layer containing 90 mass% or more of fluorinated (meth)acrylate based on the total amount of solid components is formed. Moreover, more than 50 mass% of the solid components of the fluorinated (meth)acrylate is a fluorinated (meth)acrylate (fluorine compound 1) with a polar component γp of the surface free energy of 18 mN / m or more. Correspondingly, in Examples 1 to 3, a water contact angle of 100° or more, an oleic acid contact angle of 73° or more, an oleic acid sliding angle of 25° or less, a surface free energy of 30 mN / m or less, and a visual reflectance of 2.0% or less were all obtained, and high stain resistance and high abrasion resistance evaluated as A or B were obtained respectively. In addition, Examples 1 and 2 differed only in the thickness of the antifouling layer, but Example 1 with a thinner antifouling layer was more excellent in abrasion resistance.

[0223] On the other hand, in Comparative Examples 1 and 2, only a fluorinated (meth)acrylate with a polar component γp of the surface free energy less than 18 mN / m was used as the fluorinated (meth)acrylate constituting the antifouling layer. Correspondingly, the abrasion resistance was low (C). It is considered that the reason is that due to the low adhesion between the low refractive index layer and the antifouling layer, when friction is carried out with a felt, the surface of the antifouling layer is worn, and wear marks or damages accompanied by changes in reflection characteristics are generated.

[0224] In Comparative Example 3, the content of the fluorine-containing (meth)acrylate in the antifouling layer is less than 90% by mass. Correspondingly, the abrasion resistance is low (C). From this result, it can be said that when the fluorine-containing (meth)acrylate is not contained in an amount of 90% by mass or more based on the total solid content in the antifouling layer, sufficient abrasion resistance cannot be obtained. Even if a binder resin not containing fluorine is added instead, the improvement in the adhesion to the low refractive index layer and the resulting improvement in abrasion resistance cannot be achieved.

[0225] In Comparative Example 5, an antifouling layer containing a fluorine-containing compound was not provided on the surface of the low refractive index layer. In this Comparative Example 5, the water contact angle is less than 100°, the oleic acid contact angle is as low as less than 73°, and the oleic acid sliding angle is as large as more than 25°. In addition, the measured value of the surface free energy in the surface of the produced film also exceeds 30 mN / m. Correspondingly, the evaluation result of the antifouling property is also low (C). In addition, the smoothness of the surface is insufficient and the abrasion resistance is low (C).

[0226] In Comparative Example 4, similar to Comparative Example 5, an antifouling layer was not provided on the surface of the low refractive index layer. Instead, a fluorine-containing compound was added to the low refractive index layer. In this Comparative Example 4, by adding a fluorine-containing compound to the low refractive index layer, the antifouling property was improved (B) compared with Comparative Example 5, but it was inferior to Examples 1 to 3. The abrasion resistance was still low (C). This indicates that even if a fluorine-containing compound is added to the low refractive index layer instead of the antifouling layer, the same effect as that of the antifouling layer provided as an independent layer on the surface of the low refractive index layer cannot be obtained.

[0227] As described above, the antireflection film has a substrate film, a hard coat formed on the surface of the substrate film, a low refractive index layer formed on the surface of the hard coat, and an antifouling layer formed on the surface of the low refractive index layer. The antifouling layer is composed of a cured product of a composition containing a fluorine-containing (meth)acrylate. Based on the total solid content of the antifouling layer, the content of the fluorine-containing (meth)acrylate in the antifouling layer is 90% by mass or more, and 50% or more of the solid components of the fluorine-containing (meth)acrylate are fluorine-containing (meth)acrylates with a surface free energy polar component γp of 18 mN / m or more. Thus, the antireflection film has high antifouling property and abrasion resistance.

[0228] The embodiments of the present invention have been described above, but the present invention is not limited to any of the above embodiments, and various changes can be made without departing from the gist of the present invention.

[0229] Explanation of Reference Signs

[0230] 10, 20, 30, 40 antireflection films

[0231] 12 Substrate film

[0232] 14 Hard coat

[0233] 15 High refractive index layer

[0234] 16 Low refractive index layer

[0235] 18 Antifouling layer

[0236] 22 Transparent adhesive layer

[0237] 24 Release film

[0238] 26 Adhesive layer

[0239] 28 Protective film.

Claims

1. An antireflection film, characterized in that it has a substrate film, a hard coat formed on the surface of the substrate film, a low refractive index layer formed on the surface of the hard coat, and an antifouling layer formed on the surface of the low refractive index layer, the antifouling layer is composed of a cured product of a composition containing a fluorine-containing (meth)acrylate, based on the total solid content of the antifouling layer, the content of the fluorine-containing (meth)acrylate in the antifouling layer is 90% by mass or more, more than 50% by mass of the solid component of the fluorine-containing (meth)acrylate contained in the antifouling layer is a fluorine-containing (meth)acrylate having a surface free energy polar component γp of 18 mN / m or more.

2. The antireflection film according to claim 1, wherein The total amount of the resin component constituting the antifouling layer is a fluorine-containing (meth)acrylate.

3. The antireflection film according to claim 1 or 2, wherein, The surface free energy hydrogen bond component γh of the fluorine-containing (meth)acrylate having a surface free energy polar component γp of 18 mN / m or more contained in the antifouling layer is 8 mN / m or less, and the dispersion component γd is 8 mN / m or more and 40 mN / m or less.

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