Anti-reflective film and method for manufacturing an anti-reflective film

Abstract

To provide: an antireflection film having high antireflection properties and excellent scratch resistance; and a method for producing such an antireflection film.SOLUTION: An antireflection film 10 includes: a base material film 12; a hard coating layer 14 formed on the surface of the base material film 12; a high refractive index layer 16 that is formed on the surface of the hard coating layer 14; and a low refractive index layer 18 that is formed on the surface of the high refractive index layer 16. The high refractive index layer 16 is composed of a cured product of an ionizing radiation curable composition containing a (meth)acrylate compound that has a reactive group and titanium oxide particles that are surface-treated with a silane coupling agent having a reactive group that is capable of forming a bond with the (meth)acrylate compound, and an average particle diameter D50 of the titanium oxide particles in the volume-based cumulative particle size distribution is 20 nm or more, while a 90% particle diameter D90 of the titanium oxide particles in the volume-based cumulative particle size distribution is 120 nm or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an antireflection film and a method for manufacturing the same, and more particularly, to an antireflection film suitably used for the surface of displays such as touch panels of liquid crystal displays, organic EL displays, smartphones, etc., and a method for manufacturing such an antireflection film.

Background Art

[0002] On the surface of displays such as touch panels of liquid crystal displays, organic EL displays, smartphones, etc., an antireflection film may be disposed to prevent external light from reflecting onto the screen. For example, Patent Document 1 discloses an antireflection film having a medium refractive index layer, a high refractive index layer, and a low refractive index layer on a base film. Examples of the composition constituting the high refractive index layer include a mixture of titanium oxide and urethane acrylate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, with the spread of displays assuming touch operations outdoors, such as smartphones and car navigation systems, there has been an increasing demand for antireflection films that have high antireflection properties and are difficult to be scratched even when touch operations are repeated. However, although the antireflection film of Patent Document 1 is excellent in antireflection properties, its scratch resistance cannot be said to be sufficient for use on the surface of displays such as mobile terminals, and even higher scratch resistance is required.

[0005] The problem that this invention aims to solve is to provide an anti-reflective film having high anti-reflective properties and excellent scratch resistance, and a method for manufacturing such an anti-reflective film. [Means for solving the problem]

[0006] To solve the above problems, the anti-reflective film according to the present invention comprises a base film, a hard coat layer formed on the surface of the base film, a high refractive index layer formed on the surface of the hard coat layer, and a low refractive index layer formed on the surface of the high refractive index layer, wherein the high refractive index layer is composed of a cured product of an ionizing radiation curable composition containing a (meth)acrylate compound having a reactive group and titanium oxide particles surface-treated with a silane coupling agent having a reactive group capable of bonding with the (meth)acrylate compound, wherein the average particle diameter D50 in the volume-based cumulative particle size distribution of the titanium oxide particles is 20 nm or more, and the 90% particle diameter D90 in the volume-based cumulative particle size distribution is 120 nm or less.

[0007] Here, the refractive index of the high refractive index layer at a wavelength of 550 nm is preferably 1.83 or more and 2.00 or less, and the refractive index of the low refractive index layer at a wavelength of 550 nm is preferably 1.35 or more and 1.49 or less. Furthermore, the anti-reflective film may have a medium refractive index layer between the hard coat layer and the high refractive index layer, the medium refractive index layer having a refractive index at a wavelength of 550 nm that is higher than the refractive index of the hard coat layer and lower than the refractive index of the high refractive index layer.

[0008] The present invention relates to a method for producing an anti-reflective film, comprising: forming a hard coat layer on the surface of a base film; applying an ionizing radiation-curable composition containing a particle dispersion in which titanium oxide particles surface-treated with a (meth)acrylate compound having a reactive group and a silane coupling agent having a reactive group capable of bonding with the (meth)acrylate compound are dispersed in a solvent to form a high refractive index layer; and forming a low refractive index layer on the surface of the high refractive index layer, wherein the content of titanium atoms in the particle dispersion is 40% by mass or more and 80% by mass or less of the total solid content. [Effects of the Invention]

[0009] The anti-reflective film according to the present invention comprises a base film, a hard coat layer formed on the surface of the base film, a high refractive index layer formed on the surface of the hard coat layer, and a low refractive index layer formed on the surface of the high refractive index layer. The high refractive index layer is composed of a cured product of an ionizing radiation-curable composition containing a (meth)acrylate compound having a reactive group and titanium oxide particles surface-treated with a silane coupling agent having a reactive group capable of bonding with the (meth)acrylate compound. The average particle diameter D50 in the volume-based cumulative particle size distribution of the titanium oxide particles is 20 nm or more, and the 90% particle diameter D90 in the volume-based cumulative particle size distribution is 120 nm or less, thus providing high anti-reflective properties and excellent scratch resistance. The surface treatment of the titanium oxide particles contained in the high refractive index layer with a silane coupling agent having a reactive group capable of bonding with the (meth)acrylate compound, and the fact that D50 and D90 are within the above-mentioned predetermined ranges, provides a high effect in achieving both anti-reflective properties and scratch resistance.

[0010] Here, if the refractive index of the high refractive index layer at a wavelength of 550 nm is 1.83 or more and 2.00 or less, and the refractive index of the low refractive index layer at a wavelength of 550 nm is 1.35 or more and 1.49 or less, then the anti-reflective film can achieve a high degree of both improved scratch resistance and low reflectivity.

[0011] Furthermore, if the anti-reflective film has a medium refractive index layer between the hard coat layer and the high refractive index layer, the refractive index at a wavelength of 550 nm is higher than that of the hard coat layer and lower than that of the high refractive index layer, the anti-reflective properties of the anti-reflective film can be further enhanced.

[0012] The present invention relates to a method for manufacturing an anti-reflective film, comprising: forming a hard coat layer on the surface of a base film; applying an ionizing radiation-curable composition containing a particle dispersion in which titanium oxide particles surface-treated with a (meth)acrylate compound having a reactive group and a silane coupling agent having a reactive group capable of bonding with the (meth)acrylate compound are dispersed in a solvent to form a high refractive index layer; and forming a low refractive index layer on the surface of the high refractive index layer, wherein the content of titanium atoms in the particle dispersion relative to 100% by mass of the total solid content is 40% by mass or more and 80% by mass or less, thereby enabling the production of an anti-reflective film with high anti-reflective properties and excellent scratch resistance. Here, by setting the content of titanium atoms in the particle dispersion within the above range, a high-quality high refractive index layer with a high refractive index and high scratch resistance can be suitably produced. [Brief explanation of the drawing]

[0013] [Figure 1] This is a cross-sectional view of an anti-reflective film according to the first embodiment of the present invention. [Figure 2] This is a cross-sectional view of an anti-reflective film according to a second embodiment of the present invention. [Figure 3] This is a cross-sectional view of an anti-reflective film according to a third embodiment of the present invention. [Figure 4] This is a cross-sectional view of an anti-reflective film according to a fourth embodiment of the present invention. [Modes for carrying out the invention]

[0014] The present invention will be described in detail below. In this specification, unless otherwise specified, all physical properties refer to values ​​at room temperature and in air.

[0015] <Anti-reflective film of the first embodiment> Figure 1 is a cross-sectional view of an anti-reflective film according to the first embodiment of the present invention. As shown in Figure 1, the anti-reflective film 10 according to the first embodiment of the present invention comprises a base film 12, a hard coat layer 14 formed on the surface of the base film 12, a high refractive index layer 16 formed on the surface of the hard coat layer 14, and the surface of the high refractive index layer 16 above The anti-reflective film 10 has a base film 12, a hard coat layer 14, a high refractive index layer 16, and a low refractive index layer 18 in this order. Preferably, the base film 12 and the hard coat layer 14 are in direct contact without any other layers in between. Also, it is preferable that the high refractive index layer 16 and the low refractive index layer 18 are in direct contact without any other layers in between. In this embodiment, the hard coat layer 14 and the high refractive index layer 16 are also in direct contact without any other layers in between.

[0016] (Base film) The base film 12 is not particularly limited as long as it is transparent. Examples of base film 12 include transparent polymer films and glass films. Transparency means that the total light transmittance in the visible light wavelength range is 50% or more, and more preferably 85% or more. The above total light transmittance can be measured in accordance with JIS K7361-1 (1997). The thickness of the base film 12 is not particularly limited, but from the viewpoint of ease of handling, it is preferably in the range of 2 μm to 500 μm. More preferably it is in the range of 2 μm to 200 μm. In general, "film" refers to a material with a thickness of less than 0.25 mm, but even if the thickness is 0.25 mm or more, if it can be wound into a roll, it is also included as a "film".

[0017] Examples of the polymer material of 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, polyolefin resins such as polypropylene resin, polyethylene resin, 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 these, or may be composed of a combination of two or more. Among these, 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.

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

[0019] (Hard coat layer) The hard coat layer 14 contributes to the improvement of the scratch resistance of the antireflection film 10. The hard coat layer 14 is composed of a cured product of a radiation-curable composition containing a (meth)acrylate compound having a reactive group. The radiation means electromagnetic waves or charged particle beams having energy quanta capable of polymerizing or crosslinking molecules. Examples of the 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 these, ultraviolet rays (UV) are particularly preferable from the viewpoint of productivity. Hereinafter, the radiation-curable composition may be simply referred to as a curable composition. In the present specification, “(meth)acrylate” means “at least one of acrylate and methacrylate”. “(meth)acryloyl” means “at least one of acryloyl and methacryloyl”. “(meth)acrylic” means “at least one of acrylic and methacrylic”. A “(meth)acrylate compound” is a compound having a (meth)acryloyl group, and examples thereof include monomers, oligomers, prepolymers, and the like. Hereinafter, the (meth)acrylate compound may be simply referred to as (meth)acrylate.

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

[0021] Examples of (meth)acrylates include urethane (meth)acrylate, silicone (meth)acrylate, alkyl (meth)acrylate, and aryl (meth)acrylate. Of these, urethane (meth)acrylate, particularly urethane (meth)acrylate oligomers, are preferred. Specific examples of urethane (meth)acrylate include those obtained by reacting a polyisocyanate compound with a hydroxyl group-containing (meth)acrylate compound and, if necessary, a polyol compound. Examples of polyisocyanate compounds include diisocyanate compounds such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and 4,4'-diphenylmethane diisocyanate, as well as their nurate-modified, adduct-modified, and biuret-modified forms. Examples of hydroxyl group-containing (meth)acrylate compounds include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, trimethylolpropane diacrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and their polyoxyalkylene and polylactone modified forms. Examples of polyol compounds include ethylene glycol, pro Pi Examples include ethylene glycol, butanediol, hexanediol, polyoxyethylene glycol, polyoxypropylene glycol, glycerin, trimethylolpropane, pentaerythritol, biphenol, and bisphenol. When the curable composition for forming the hard coat layer 14 contains urethane (meth)acrylate as an ultraviolet curable resin, the hard coat layer 14 has appropriate flexibility, which increases the bending resistance of the anti-reflective film 10, making it suitable for use in flexible displays that are repeatedly bent, such as foldable displays and rollable displays. Furthermore, even if the base film 12 is formed from, for example, polycycloolefin or cycloolefin copolymer and is relatively brittle, cracking of the base film 12 is easily suppressed.

[0022] It is preferable that the curable composition further contains a pentaerythritol (meth)acrylate compound as the (meth)acrylate. Specific examples of pentaerythritol (meth)acrylate compounds include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tetra(meth)acrylate, tripentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol octa(meth)acrylate, and the like. In particular, it is preferable that the curable composition contains pentaerythritol tri(meth)acrylate.

[0023] The curable composition forming the hard coat layer 14 may or may not contain a non-UV curable resin in addition to a UV-curable resin. Furthermore, the curable composition forming the hard coat layer 14 may contain a photopolymerization initiator. Additionally, generally available additives may be included as needed. Examples of additives include dispersants, leveling agents, defoamers, vibration modifiers, antifouling agents, antibacterial agents, flame retardants, slip agents, antistatic agents, inorganic particles, and resin particles. Additionally, solvents may be included as needed.

[0024] Examples of non-UV curable resins include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyester resins, polyether resins, polyolefin resins, and polyamide resins. Examples of thermosetting resins include unsaturated polyester resins, epoxy resins, alkyd resins, and phenolic resins.

[0025] Examples of photopolymerization initiators include alkylphenone-based, acylphosphine oxide-based, and oxime ester-based photopolymerization initiators. Examples of alkylphenone-based photopolymerization initiators include 2,2'-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl-ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropane-1- Examples include 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, and N,N-dimethylaminoacetophenone. Examples of acylphosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Examples of oxime ester-based photopolymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime). These photopolymerization initiators may be used individually or in combination of two or more.

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

[0027] Inorganic particles and resin particles are added to the hard coat layer 14 for purposes such as preventing blocking of the hard coat layer 14 and adjusting the refractive index of the hard coat layer 14. By forming fine surface irregularities on the hard coat layer 14 with the added inorganic particles and resin particles, it is easier to suppress blocking, where the front and back surfaces adhere to each other, when the hard coat film, consisting of the base film 12 and the hard coat layer 14, is wound into a roll before the high refractive index layer 16 is formed.

[0028] Examples of inorganic particles that can adjust the refractive index of the hard coat layer 14 include metal oxide particles made from metal oxides such as titanium, zirconium, tin, zinc, silicon, niobium, aluminum, chromium, magnesium, germanium, gallium, antimony, and platinum. These may be used individually as optically adjustable inorganic particles, or in combination of two or more types. Among these, titanium oxide and zirconium oxide are particularly preferred from the viewpoint of achieving both high refractive index and transparency. Examples of resin particles include resin particles made from resins such as (meth)acrylic resin, styrene resin, styrene-(meth)acrylic resin, urethane resin, polyamide resin, silicone resin, epoxy resin, phenolic resin, polyethylene resin, and cellulose. These may be used individually as resin particles, or in combination of two or more types.

[0029] The thickness of the hard coat layer 14 is not particularly limited, but is preferably 0.5 μm or more from the viewpoint of having sufficient hardness. More preferably 0.75 μm or more. Furthermore, it is preferably 20 μm or less from the viewpoint of easily suppressing curl caused by the difference in thermal shrinkage with the base film 12. More preferably 10 μm or less. The thickness of the hard coat layer 14 is the thickness of the relatively smooth portion in the thickness direction where there are no irregularities caused by inorganic particles or resin particles.

[0030] From the viewpoint of suppressing interference unevenness arising from the difference in refractive indices between the transparent substrate film 12 and the hard coat layer 14, the refractive index of the hard coat layer 14 is preferably in the range of 1.49 to 1.56. The arithmetic mean roughness Ra of the surface on which the surface irregularities of the hard coat layer 14 are formed is preferably in the range of 0.3 nm to 20 nm from the viewpoint of suppressing blocking, etc. More preferably it is 0.5 nm or more, and also 10 nm or less.

[0031] Solvents used in the curable composition for forming the hard coat layer 14 include alcohol-based solvents such as ethanol, isopropyl alcohol (IPA), n-butyl alcohol (NBA), ethylene glycol monomethyl ether (EGM), ethylene glycol monoisopropyl ether (IPG), propylene glycol monomethyl ether (PGM), and diethylene glycol monobutyl ether; ketone-based solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, and acetone; aromatic solvents such as toluene and xylene; ester-based solvents such as ethyl acetate (EtAc), propyl acetate, isopropyl acetate, and butyl acetate (BuAc); and amide-based solvents such as N-methylpyrrolidone, acetamide, and dimethylformamide. These solvents may be used individually or in combination of two or more.

[0032] The solid content concentration (concentration of components other than the solvent) of the curable composition should be determined appropriately, taking into consideration the coating properties, film thickness, etc. For example, it may be set to 1% to 90% by mass, 1.5% to 80% by mass, or 2% to 70% by mass.

[0033] (High refractive index layer) In the anti-reflective film 10 according to this embodiment, a high refractive index layer 16 is provided on the surface of the hard coat layer 14. By providing the high refractive index layer 16 between the hard coat layer 14 and the low refractive index layer 18, the anti-reflective film 10 exhibits a higher anti-reflective effect. The high refractive index layer 16 is a layer having a higher refractive index than the hard coat layer 14 and the low refractive index layer 18.

[0034] The high refractive index layer 16 is composed of a cured product of an ionizing radiation-curable composition containing a (meth)acrylate compound having a reactive group and titanium oxide particles surface-treated with a silane coupling agent having a reactive group capable of bonding with the (meth)acrylate compound. As described above for the hard coat layer, ionizing radiation includes various electromagnetic waves and charged particle beams, but ultraviolet (UV) radiation is particularly preferred. Furthermore, the reactive groups contained in the (meth)acrylate compound and the silane coupling agent are preferably UV-reactive.

[0035] Examples of (meth)acrylate compounds having a reactive group include urethane (meth)acrylate, silicone (meth)acrylate, alkyl (meth)acrylate, and aryl (meth)acrylate. Furthermore, the (meth)acrylate compound may have only a (meth)acryloyl group as its reactive group, or it may have another reactive group in addition to the (meth)acryloyl group.

[0036] The (meth)acrylate may consist only of monofunctional (meth)acrylate, or it may consist of polyfunctional (meth)acrylate, or it may consist of a combination of monofunctional (meth)acrylate and polyfunctional (meth)acrylate. It is more preferable that the (meth)acrylate includes polyfunctional (meth)acrylate.

[0037] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, and 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, tricyclodecanyl (meth)acrylate, di Cyclopentanyl (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,Examples include ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate.

[0038] Examples of polyfunctional (meth)acrylates include difunctional (meth)acrylates, trifunctional (meth)acrylates, and tetrafunctional (meth)acrylates. More specifically, these 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, and trimethylolpropane tri(meth)acrylate. Examples include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tetra(meth)acrylate, tripentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, and tripentaerythritol octa(meth)acrylate. The (meth)acrylate having a reactive group may consist of one type or two or more types.

[0039] The polyfunctional (meth)acrylate preferably contains a dimer. The polyfunctional (meth)acrylate dimer has excellent curing speed and can easily increase the curing rate of the curable composition, thereby further improving scratch resistance. In particular, it is preferable to include at least one selected from the group consisting of dimers of pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate, and more preferably to include at least one selected from the group consisting of dimers of pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0040] The content of the above-mentioned dimer is preferably in the range of 25% by mass or more and 50% by mass or less, based on the total solid content of the (meth)acrylate compound, from the viewpoint of scratch resistance, transparency, and solubility in solvents. More preferably, it is 30% by mass or more and 40% by mass or less.

[0041] Titanium oxide particles are used to increase the refractive index of the high refractive index layer 16. While rutile, anatase, and brookite crystal structures are known for titanium dioxide, the rutile type is preferred from the viewpoint of having a high refractive index and low photocatalytic activity. By using titanium dioxide particles with low photocatalytic activity, the modification of the high refractive index layer 16 due to photoreaction can be suppressed. The shape of the titanium dioxide particles is not particularly limited and may be spherical, needle-shaped, flake-shaped, rod-shaped, fibrous, or irregular in shape. It is preferable that the titanium dioxide particles are solid.

[0042] The titanium dioxide particles are surface-treated with a silane coupling agent having a reactive group capable of bonding with (meth)acrylate compounds. Surface treatment with a silane coupling agent can more effectively suppress the photocatalytic activity of the titanium dioxide particles. Furthermore, because the silane coupling agent has a reactive group capable of bonding with (meth)acrylate compounds, the titanium dioxide particles bond strongly to the (meth)acrylate contained in the high refractive index layer 16, improving the scratch resistance of the anti-reflective film. Silane coupling agents generally have hydrolyzable groups and other functional groups bonded to silicon atoms in their molecules. Here, a hydrolyzable group refers to a substituent that is directly bonded to a silicon atom and can produce a siloxane bond through hydrolysis and / or condensation reactions. Examples of hydrolyzable groups include halogen atoms, alkoxy groups, acyloxy groups, and alkenyloxy groups. When the hydrolyzable group has carbon atoms, the number of carbon atoms is preferably 6 or less, and more preferably 4 or less. In particular, alkoxy groups with 4 or fewer carbon atoms or alkenyloxy groups with 4 or fewer carbon atoms are preferred. The hydrolyzable groups undergo hydrolysis, forming bonds with the oxygen atoms on the surface of the titanium dioxide particles, thereby surface-treating the titanium dioxide particles.

[0043] The silane coupling agent used here contains a reactive group capable of forming a bond with the (meth)acrylate compound, in addition to the hydrolyzable group mentioned above. Examples of reactive groups include carbon-carbon unsaturated double bond groups such as (meth)acryloyl groups, vinyl groups, styryl groups, and allyl groups, and ring-opening polymerizable groups such as epoxy groups and oxetanyl groups. These reactive groups are ultraviolet reactive. In the high refractive index layer 16 containing a (meth)acrylate compound having a reactive group and titanium oxide particles surface-treated with a silane coupling agent having a reactive group, the reactive group of the (meth)acrylate compound and the reactive group of the silane coupling agent react to form a bond.

[0044] Examples of silane coupling agents having a carbon-carbon unsaturated double bond group as a reactive group include p-styryltrimethoxysilane, 2-(allyloxymethyl)acrylate (trimethoxysilyl)propyl, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, p-styryltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and 7-octenyltrimethoxysilane.

[0045] Examples of silane coupling agents having a ring-opening polymerizable group as a reactive group include 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 8-glycidoxyoctyltrimethoxysilane.

[0046] Of these, carbon-carbon unsaturated double bond groups are preferred from the viewpoint of reactivity with (meth)acrylate compounds, and among them, silane coupling agents having ethylenically active carbon-carbon double bond groups such as (meth)acryloyl groups, vinyl groups, styryl groups, and allyl groups are particularly preferred.

[0047] The content of the silane coupling agent is preferably in the range of 1 part by mass or more and 40 parts by mass or less per 100 parts by mass of titanium oxide particles. This enhances the effect of the surface treatment by the silane coupling agent and maintains high scratch resistance and refractive index of the high refractive index layer 16. More preferably, it is 5 parts by mass or more and 30 parts by mass or less. Silane coupling agent that is not bound to the titanium oxide particles may remain in the high refractive index layer 16, and the preferred content range described herein refers to the total content of the silane coupling agent, including the silane coupling agent that is not bound to the titanium oxide particles.

[0048] Furthermore, in order to more effectively suppress the photocatalytic activity of titanium oxide particles, the particle surface may be coated with an inorganic compound other than a silane coupling agent before surface treatment with a silane coupling agent, or a dissimilar metal may be solid-dissolved inside the titanium oxide crystal. Examples of inorganic compounds to be used for coating include oxides or hydroxides of zinc, cerium, iron, silicon, zirconium, and aluminum. Examples of dissimilar metals to be solid-dissolved inside the crystal include tin, cobalt, vanadium, chromium, manganese, copper, antimony, tungsten, platinum, mercury, lead, and bismuth. Of these, it is preferable to coat the surface of the titanium oxide particles with an aluminum oxide or hydroxide.

[0049] The high refractive index layer 16 may contain a dispersant. The dispersant contributes to maintaining (stabilizing) the dispersed state of titanium oxide particles in the high refractive index layer forming composition. This smooths the surface after the formation of the high refractive index layer 16, improving the scratch resistance and transparency of the anti-reflective film.

[0050] The type of dispersant is not particularly limited, and for example, coupling agents such as silanes, titanates, and zircoaluminates, organometallic compounds such as metal chelates and metal alkoxides, surfactants such as polyoxyethylene alkyl phosphates and polyesterates, or commercially available resin-type dispersants may be added.

[0051] The dispersant content is preferably in the range of 15 parts by mass or more and 75 parts by mass or less per 100 parts by mass of silane coupling agent. More preferably it is 20 parts by mass or more, and 70 parts by mass or less.

[0052] The total amount of the silane coupling agent and dispersant is preferably in the range of 10 parts by mass to 40 parts by mass per 100 parts by mass of titanium oxide particles. When the total content of the silane coupling agent and dispersant is 10 parts by mass or more, the effects brought about by the addition of the silane coupling agent and dispersant described above can be improved. On the other hand, by keeping the content to 40 parts by mass or less, it is possible to suppress situations in which the scratch resistance of the high refractive index layer 16 decreases or the refractive index decreases, making it difficult to obtain a good anti-reflective effect. From this viewpoint, the content is more preferably in the range of 15 parts by mass to 35 parts by mass, and even more preferably in the range of 15 parts by mass to 30 parts by mass.

[0053] The average particle size (D50) of titanium dioxide particles, based on volume, is 20 nm or more. If D50 is less than 20 nm, the dispersibility of particles in the high refractive index layer 16 deteriorates. This necessitates the addition of a large amount of dispersant to the composition to improve the dispersibility of titanium dioxide particles. As a result, the titanium dioxide content in the high refractive index layer 16 becomes insufficient, leading to a decrease in the scratch resistance of the high refractive index layer 16 and a decrease in the refractive index, making it difficult to obtain a good anti-reflective effect. From the viewpoint of suppressing this phenomenon, D50 is set to 20 nm or more, preferably 25 nm or more, more preferably 30 nm or more, and particularly preferably 34 nm or more. In this specification, parameters related to particle size, such as D10, D50, and D90, refer to values ​​in the volume-based cumulative particle size distribution. The volume-based cumulative particle size distribution can be obtained by dynamic light scattering. Furthermore, particle size includes not only the primary particle size but also the secondary particle size, which is the aggregate of particles.

[0054] The volume-based average particle diameter (D50) of titanium dioxide particles is not particularly limited, but is preferably 100 nm or less. This makes it easier to set the volume-based cumulative 90% particle diameter (D90), described later, to 120 nm or less, and as a result, it becomes easier to suppress situations where the particle diameter becomes excessively larger than the film thickness of the high refractive index layer 16, which reduces the surface smoothness and thus the scratch resistance and transparency of the anti-reflective film. From this viewpoint, D50 is more preferably 80 nm or less, and even more preferably 60 nm or less.

[0055] The volume-based cumulative 90% particle diameter (D90) of titanium dioxide particles is 120 nm or less. If D90 exceeds 120 nm, the larger titanium dioxide particles may form irregularities on the surface of the high refractive index layer 16, reducing smoothness and potentially decreasing the scratch resistance and transparency of the anti-reflective film. To suppress this phenomenon, D90 is set to 120 nm or less, preferably 110 nm or less, and more preferably 100 nm or less.

[0056] On the other hand, the volume-based cumulative 90% particle diameter (D90) of the titanium oxide particles is not particularly limited, but is preferably 50 nm or greater. If D90 is 50 nm or greater, it becomes easier to control D50 to 20 nm or greater, which makes it easier to improve the scratch resistance and anti-reflective properties of the high refractive index layer 16. From this viewpoint, D90 is more preferably 55 nm or greater, and even more preferably 60 nm or greater.

[0057] The cumulative 10% particle size (D10) of titanium dioxide particles by volume is not particularly limited, but is preferably in the range of 10 nm to 40 nm. When D10 is in this range, there are relatively few extremely small particles, which improves the dispersibility of the titanium dioxide particles. This makes it easier to disperse the titanium dioxide particles without requiring a large amount of dispersant, allowing for a sufficient titanium dioxide content in the high refractive index layer 16, and making it easier to obtain good scratch resistance and anti-reflective properties. From this viewpoint, D10 is more preferably 12 nm or more, even more preferably 15 nm or more, and even more preferably 35 nm or less, and even more preferably 30 nm or less.

[0058] The PDI, which represents the particle size distribution width of titanium dioxide particles, is preferably 4.0 or less. Here, PDI is a polydispersity index expressed as (D90-D10) / D50, and the smaller this value, the more uniform the particle size. When the PDI is 4.0 or less, the particle size of the titanium dioxide is uniform, making it easier to obtain smoothness on the surface of the high refractive index layer 16. From this viewpoint, the PDI is preferably 3.0 or less, and more preferably 2.5 or less. There is no particular lower limit to the PDI, but it is usually 1.5 or higher, or 2.0 or higher.

[0059] The high refractive index layer 16 may contain inorganic oxide particles other than titanium oxide in addition to titanium oxide particles. Other inorganic oxide particles besides titanium dioxide include metal oxide particles made from metal oxides such as zirconium, silicon, aluminum, calcium, iron, copper, zinc, yttrium, niobium, molybdenum, indium, tin, tantalum, tungsten, lead, bismuth, cerium, and antimony. Among these, zirconium oxide, zinc oxide, niobium oxide, indium oxide, tin oxide, tungsten oxide, and antimony oxide particles are preferred from the viewpoint of high refractive index and preventing discoloration. These may be used individually as inorganic oxide particles, or in combination of two or more. In order that the inorganic oxide particles other than titanium dioxide do not significantly impair the properties that titanium dioxide particles exhibit in the high refractive index layer 16, such as high refractive index and improved scratch resistance, it is preferable that the inorganic oxide particles other than titanium dioxide have the same particle size distribution (D50, D90, D10, PDI) as those listed above as preferred for titanium dioxide particles, and that their content in the high refractive index layer 16 is kept lower than that of titanium dioxide particles. Inorganic oxide particles other than titanium dioxide may also be surface-treated with a silane coupling agent.

[0060] When adding titanium oxide particles surface-treated with a silane coupling agent to a composition for forming a high refractive index layer 16, it is preferable to first disperse the surface-treated titanium oxide particles in a solvent to form a particle dispersion before incorporating it into the composition for forming the high refractive index layer. In this case, the particle dispersion may contain not only titanium oxide particles surface-treated with a silane coupling agent, but also silane coupling agents not bound to the titanium oxide particles, inorganic compounds, dispersants, and other inorganic oxide particles. By pre-dispersing the surface-treated titanium oxide particles in a particle dispersion before incorporating them with the (meth)acrylate compound, the surface-treated titanium oxide particles can be dispersed more efficiently in the composition for forming the high refractive index layer.

[0061] In the particle dispersion incorporated into the composition for forming a high refractive index layer, the content of titanium atoms relative to 100% by mass of the total solid content is preferably 35% by mass or more. If the titanium atom content is 35% by mass or more, the amount of titanium oxide contained in the high refractive index layer 16 can be increased, and the refractive index of the high refractive index layer 16 can be increased. From this viewpoint, the titanium atom content is more preferably 40% by mass or more, and even more preferably 45% by mass or more. On the other hand, the titanium atom content relative to 100% by mass of the total solid content is preferably 80% by mass or less. If the titanium atom content is 80% by mass or less, the content of silane coupling agents and dispersants can be sufficiently increased, and a good particle dispersion can be obtained. From this viewpoint, the titanium atom content is more preferably 70% by mass or less, and even more preferably 60% by mass or less. Furthermore, if a particle dispersion with a titanium atom content within the ranges listed above is used, it is easier to keep the content of titanium oxide particles in the entire high refractive index layer 16 within the preferred range described below. In a particle dispersion, the titanium atom content in the solid component can be evaluated by measuring the elemental content using an energy-dispersive X-ray analyzer.

[0062] Examples of solvents used as dispersion media for dispersing titanium dioxide particles in a particle dispersion include alcohol-based solvents such as methanol, ethanol, isopropyl alcohol, ethylene glycol monomethyl ether (EGM), propylene glycol monomethyl ether (PGM), and diethylene glycol monobutyl ether; glycol ester-based solvents such as ethylene glycol monomethyl ether acetate (EGMEA) and propylene glycol monomethyl ether acetate (PGMEA); ketone-based solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, and acetone; aromatic solvents such as toluene and xylene; and amide-based solvents such as N-methylpyrrolidone, acetamide, and dimethylformamide. These solvents may be used individually or in combination of two or more.

[0063] The titanium dioxide particle content in the entire high refractive index layer 16 is preferably 45% by mass or more and 80% by mass or less relative to 100% by mass of the solid content of the high refractive index layer 16. When the titanium dioxide particle content in the high refractive index layer 16 is 45% by mass or more relative to 100% by mass of the solid content of the high refractive index layer 16, the refractive index of the high refractive index layer 16 can be increased, resulting in good anti-reflective properties. From this viewpoint, the titanium dioxide particle content in the high refractive index layer 16 is more preferably 55% by mass or more, and even more preferably 60% by mass or more, relative to 100% by mass of the solid content of the high refractive index layer 16. Furthermore, when the titanium dioxide particle content in the high refractive index layer 16 is 80% by mass or less relative to 100% by mass of the solid content of the high refractive index layer 16, the decrease in scratch resistance can be suppressed. From this viewpoint, the titanium dioxide particle content in the high refractive index layer 16 is more preferably 75% by mass or less, and even more preferably 72% by mass or less, relative to 100% by mass of the solid content of the high refractive index layer 16. The solid components of the high refractive index layer 16, as used here, refer to components that are not immobilized in the high refractive index layer 16 and are liquid at room temperature, excluding those components. The solid components of the high refractive index layer 16 include titanium dioxide particles, (meth)acrylate compounds, silane coupling agents, dispersants, and inorganic oxide particles other than titanium dioxide. Solvents are not included.

[0064] The refractive index of the high refractive index layer 16 is not particularly limited, as long as it is higher than that of the hard coat layer 14 and the low refractive index layer 18, but is preferably 1.83 or higher and 2.00 or lower at a wavelength of 550 nm. If the refractive index is 1.83 or higher, the anti-reflective film 10 can be made low-reflectivity without drastically lowering the refractive index of the low refractive index layer 18, which will be described later. Then, by making the composition of the low refractive index layer 18 such that the refractive index is not extremely low but exhibits high scratch resistance, the anti-reflective film 10 can be made to have good scratch resistance. The refractive index of the high refractive index layer 16 is more preferably 1.85 or higher, and even more preferably 1.87 or higher. On the other hand, if the refractive index of the high refractive index layer 16 is 2.00 or lower, it is not necessary to include a large amount of titanium oxide particles in the high refractive index layer 16, thereby suppressing the shedding of titanium oxide particles from the high refractive index layer 16 and obtaining good scratch resistance. From the above viewpoint, the refractive index of the high refractive index layer 16 is more preferably 1.98 or lower, and even more preferably 1.95 or lower. In this specification, unless otherwise specified, the refractive index of a substance or material layer shall be the value at a wavelength of 550 nm.

[0065] The thickness of the high refractive index layer 16 is preferably in the range of 40 nm to 120 nm. Within this range, a good low luminous reflectance can be obtained due to the optical interference effect that occurs at the interface with other layers, thereby reducing light reflection. From this viewpoint, the thickness of the high refractive index layer 16 is preferably 50 nm or more, more preferably 60 nm or more. Also preferably 100 nm or less, and even more preferably 80 nm or less.

[0066] The arithmetic mean roughness Sa on the surface of the high refractive index layer 16 is preferably 0.3 nm to 10 nm from the viewpoint of scratch resistance. More preferably, Sa is 0.4 nm or more, and even more preferably 0.5 nm or more. Furthermore, Sa is 7 nm or less, and even more preferably 3 nm or less.

[0067] The high refractive index layer 16 can be formed using a composition containing a (meth)acrylate compound having a reactive group and titanium dioxide particles surface-treated with a silane coupling agent having a reactive group. As described above, it is preferable to add the surface-treated titanium dioxide particles to the composition in the form of a particle dispersion. In the high refractive index layer 16, after irradiation with ionizing radiation, bonds are formed between the (meth)acrylate compounds, between the surface-treated titanium dioxide particles, and between the (meth)acrylate compound and the surface-treated titanium dioxide particles via the reactive groups, thereby giving the high refractive index layer 16 high scratch resistance. As described above, it is preferable that the reactive groups contained in the (meth)acrylate compound and the silane coupling agent are ultraviolet reactive. When the (meth)acrylate compound and titanium dioxide particles have ultraviolet reactive groups, irradiating the high refractive index layer 16 formed from a composition containing the (meth)acrylate compound and surface-treated titanium dioxide particles with ultraviolet light improves the scratch resistance of the high refractive index layer 16, and thus improves the scratch resistance of the anti-reflective film 10.

[0068] The high refractive index layer 16 may contain additives as needed. Examples of such additives include antifouling agents, leveling agents, defoaming agents, vibration modifiers, antibacterial agents, flame retardants, slip agents, and refractive index modifiers.

[0069] Furthermore, the composition for forming the high refractive index layer 16 preferably includes a photopolymerization initiator if the (meth)acrylate compound has a reactive group that is reactive to ultraviolet light (i.e., if it is an ultraviolet-curable resin). In addition, the composition for forming the high refractive index layer 16 may optionally include a solvent (a solvent added separately from the solvent used as a dispersion medium in the titanium dioxide particle dispersion). The (meth)acrylate compound of the high refractive index layer 16 may be composed of an ultraviolet-curable resin, a non-ultraviolet-curable resin, or a combination of an ultraviolet-curable resin and a non-ultraviolet-curable resin.

[0070] Examples of non-UV curable resins include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyester resins, polyether resins, polyolefin resins, and polyamide resins. Examples of thermosetting resins include unsaturated polyester resins, epoxy resins, alkyd resins, and phenolic resins.

[0071] Examples of photopolymerization initiators include alkylphenone-based, acylphosphine oxide-based, and oxime ester-based photopolymerization initiators. Examples of alkylphenone-based photopolymerization initiators include 2,2'-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl-ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropane-1- Examples include 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, and N,N-dimethylaminoacetophenone. Examples of acylphosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Examples of oxime ester-based photopolymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime). These photopolymerization initiators may be used individually or in combination of two or more.

[0072] The content of the photopolymerization initiator is preferably in the range of 0.1% by mass or more and 10% by mass or less, based on the total solid content of the composition for forming the high refractive index layer 16. More preferably, it is 1% by mass or more, and 5% by mass or less.

[0073] The solvent used in the composition for forming the high refractive index layer 16 can be the same as the solvent used as the dispersion medium in the titanium dioxide particle dispersion mentioned above. Examples include alcohol-based solvents such as ethylene glycol monomethyl ether (EGM), propylene glycol monomethyl ether (PGM), and diethylene glycol monobutyl ether; ketone-based solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, and acetone; aromatic solvents such as toluene and xylene; and amide-based solvents such as N-methylpyrrolidone, acetamide, and dimethylformamide. These may be used individually or in combination of two or more solvents.

[0074] (Low refractive index layer) In the anti-reflective film 10 according to this embodiment, High refractive index layer 16 A low refractive index layer 18 is provided on the surface as an anti-reflective layer. The low refractive index layer 18 has a lower refractive index than the hard coat layer 14 and the high refractive index layer 16, and exhibits an anti-reflective effect due to a significant difference in refractive index between it and the hard coat layer 14 and the high refractive index layer 16.

[0075] The low refractive index layer 18 is not particularly limited in composition, but it is preferable that it contains inorganic oxide particles, hollow silica particles, a fluorine-containing compound, and a binder resin. As the low refractive index layer 18, for example, the one described in International Publication No. 2021 / 020504 can be suitably applied.

[0076] As the binder resin, cured products of thermosetting compounds or UV-curable compounds are preferred from the viewpoint of improving the scratch resistance of the low refractive index layer 18. Furthermore, from the viewpoint of productivity, cured products of UV-curable compounds are more preferred.

[0077] Examples of UV-curable resins include monomers, oligomers, and prepolymers having UV-reactive reactive groups. Examples of UV-reactive reactive groups include radical polymerization-type reactive groups having ethylenically unsaturated bonds, such as acryloyl groups, methacryloyl groups, allyl groups, and vinyl groups, and cationic polymerization-type reactive groups such as oxetanyl groups. Of these, acryloyl groups, methacryloyl groups, and oxetanyl groups are more preferred, and acryloyl groups and methacryloyl groups are particularly preferred. In other words, the use of (meth)acrylate is particularly preferred.

[0078] Examples of (meth)acrylates include urethane (meth)acrylate, silicone (meth)acrylate, alkyl (meth)acrylate, and aryl (meth)acrylate. The (meth)acrylate may consist only of monofunctional (meth)acrylate, or it may consist of polyfunctional (meth)acrylate, or it may consist of a combination of monofunctional (meth)acrylate and polyfunctional (meth)acrylate. It is more preferable for the (meth)acrylate to include polyfunctional (meth)acrylate.

[0079] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, and 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, tricyclodecanyl (meth)acrylate, di Cyclopentanyl (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,Examples include ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate.

[0080] Examples of polyfunctional (meth)acrylates include difunctional (meth)acrylates, trifunctional (meth)acrylates, and tetrafunctional (meth)acrylates. More specifically, these 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, and trimethylolpropane tri(meth)acrylate. Examples include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tetra(meth)acrylate, tripentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, and tripentaerythritol octa(meth)acrylate.

[0081] The UV-curable resin may consist of one type of (meth)acrylate as described above, or it may consist of two or more types. From the viewpoint of improving scratch resistance, the UV-curable resin preferably contains a polyfunctional (meth)acrylate with five or more functions, and it is also preferable to increase the content of the polyfunctional (meth)acrylate with five or more functions.

[0082] Furthermore, it is preferable that the polyfunctional (meth)acrylate contains a dimer. Dimers of polyfunctional (meth)acrylates have excellent curing speed and can easily increase the curing rate of the curable composition, thereby further improving scratch resistance. In particular, it is preferable to include at least one selected from the group consisting of dimers of pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate, and it is more preferable to include at least one selected from the group consisting of dimers of pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0083] The content of the above-mentioned dimer is preferably in the range of 25% by mass or more and 50% by mass or less, based on the total solid content of the polyfunctional (meth)acrylate, from the viewpoint of scratch resistance, transparency, and solubility in solvents. More preferably, it is 30% by mass or more and 40% by mass or less.

[0084] The inorganic oxide particles, when included in the low refractive index layer 18, form protrusions on the surface of the low refractive index layer 18. The formation of these protrusions on the surface of the low refractive index layer 18 by the inorganic oxide particles allows the low refractive index layer 18 to have good scratch resistance.

[0085] The inorganic oxide particles may be solid or hollow. It is preferable that the inorganic oxide particles are solid. A solid particle is a particle that does not substantially have internal cavities, where the proportion of cavities is less than 5% of the solid particle's volume. A hollow particle is a particle that has internal cavities, where the proportion of cavities is 5% or more of the hollow particle's volume. When the inorganic oxide particles are solid, the scratch resistance of the low refractive index layer 18 is improved, and the scratch resistance of the anti-reflective film 10 is improved. When the inorganic oxide particles are hollow, the refractive index of the low refractive index layer 18 can be lowered, reducing light reflection. In the case of hollow particles, it is preferable that the proportion of cavities is between 10% and 80% of the hollow particle's volume. A cavity proportion of 10% or more allows for a lower refractive index and reduced light reflection. More preferably, it is 20% or more, and even more preferably 30% or more. On the other hand, a cavity proportion of 80% or less suppresses a decrease in the dispersibility of the inorganic oxide particles. More preferably, it is 60% or less.

[0086] Examples of inorganic oxide particles include metal oxide particles composed of metal oxides such as zirconium, silicon, aluminum, and calcium. These may be used individually or in combination of two or more types. Among these, silica particles and alumina particles are preferred, with alumina particles being particularly preferred, from the viewpoint of having a low refractive index, excellent transparency, and high hardness.

[0087] The shape of the inorganic oxide particles is not particularly limited and may be spherical, needle-shaped, flaky, rod-shaped, fibrous, or irregular in shape. Of these, a spherical shape is preferred.

[0088] In order to obtain good scratch resistance by forming protrusions on the surface of the low refractive index layer 18 using inorganic oxide particles, the difference (rd) between the average particle diameter r of the inorganic oxide particles and the average thickness d of the low refractive index layer 18 is preferably 10 nm or more. More preferably, the difference (rd) is 15 nm or more, and even more preferably 18 nm or more. On the other hand, from the viewpoint of suppressing the height of the formed protrusions and maintaining transparency, the difference (rd) is 300 nm or less. More preferably, it is 200 nm or less, and even more preferably 100 nm or less.

[0089] The average particle diameter r of the inorganic oxide particles is preferably in the range of 60 nm to 400 nm, although this also depends on the average thickness d of the low refractive index layer 18. More preferably it is 70 nm or more, and even more preferably 90 nm or more. Furthermore, it is even more preferably 300 nm or less, and even more preferably 200 nm or less. The average particle diameter r of the inorganic oxide particles is a volume-based average arithmetic value 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, which is the aggregate of particles.

[0090] The inorganic oxide particle content in the low refractive index layer 18 is preferably 0.1% by mass or more and 4.0% by mass or less relative to 100% by mass of the solid content of the low refractive index layer 18. When the inorganic oxide particle content in the low refractive index layer 18 is 0.1% by mass or more relative to 100% by mass of the solid content of the low refractive index layer 18, excellent scratch resistance can be obtained. From this viewpoint, the inorganic oxide particle content in the low refractive index layer 18 is more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, relative to 100% by mass of the solid content of the low refractive index layer 18. Furthermore, when the inorganic oxide particle content in the low refractive index layer 18 is 4.0% by mass or less relative to 100% by mass of the solid content of the low refractive index layer 18, high transparency can be obtained. From this viewpoint, the inorganic oxide particle content in the low refractive index layer 18 is more preferably 3.5% by mass or less, and even more preferably 3.2% by mass or less, relative to 100% by mass of the solid content of the low refractive index layer 18. The solid components of the low refractive index layer 18 referred to here are those components that are not immobilized in the binder resin and are liquid at room temperature, excluding those components. The solid components of the low refractive index layer 18 include inorganic oxide particles, hollow silica particles, binder resin, and fluorine-containing compounds immobilized in the binder resin. Additives such as oil components and surfactants that are not immobilized in the binder resin are not included.

[0091] Hollow silica particles are particles with an average particle diameter smaller than the average thickness of the low refractive index layer 18. It is preferable that the hollow silica particles have an average particle diameter smaller than the inorganic oxide particles that form protrusions on the surface of the low refractive index layer 18. Hollow silica particles are particles that do not substantially contribute to the formation of surface irregularities in the low refractive index layer 18. Hollow silica particles are particles that have cavities inside, and the proportion of cavities is 5% or more of the volume. "Hollow" refers to a shell structure consisting of an outer shell and internal cavities, or a porous structure having numerous cavities. The hollow structure of hollow silica particles allows for a reduction in the refractive index of the low refractive index layer 18, thereby reducing light reflection. The shape of the hollow silica particles is not particularly limited, but spherical, spindle-shaped, oval, plate-shaped, cubic, and irregular shapes are preferred. Of these, spherical, plate-shaped, and cubic shapes are particularly preferred.

[0092] In hollow silica particles, the proportion of cavities is preferably 10% to 80% of the volume. When the proportion of cavities is 10% or more of the volume, the refractive index can be lowered, reducing light reflection. More preferably, it is 20% or more of the volume, and even more preferably 30% or more of the volume. On the other hand, when the proportion of cavities is 80% or less of the volume, the decrease in the dispersibility of the hollow silica particles can be suppressed. More preferably, it is 60% or less of the volume.

[0093] The average particle diameter of the hollow silica particles is preferably between 5 nm and 100 nm, although this also depends on the average thickness of the low refractive index layer 18. More preferably, it is 20 nm or more, and even more preferably, 40 nm or more. Furthermore, it is more preferably 80 nm or less, and even more preferably, 70 nm or less. When the average particle diameter of the hollow silica particles is within these preferred ranges, excellent anti-reflective effect and transparency of the low refractive index layer 18 can be obtained. The average particle diameter is a volume-based average arithmetic value obtained by the laser diffraction / scattering method in accordance with JIS Z8825. This includes not only the primary particle diameter but also the secondary particle diameter, which is the aggregate of particles.

[0094] The refractive index of the hollow silica particles is preferably in the range of 1.01 to 1.45. More preferably, it is in the range of 1.15 to 1.38, and even more preferably, in the range of 1.15 to 1.35. When the refractive index of the hollow silica particles is within this range, an excellent anti-reflective effect can be obtained.

[0095] The content of hollow silica particles in the low refractive index layer 18 should be 6.0% by mass or more and 49.9% by mass or less, relative to 100% by mass of the solid content of the low refractive index layer 18. That's all.This allows for excellent anti-reflective properties. Furthermore, from this viewpoint, the content of hollow silica particles in the low refractive index layer 18 is more preferably 10% by mass or more, even more preferably 20% by mass or more, and particularly preferably 30% by mass or more, relative to 100% by mass of the solid content of the low refractive index layer 18. When the content of hollow silica particles in the low refractive index layer 18 is 49.9% by mass or less relative to 100% by mass of the solid content of the low refractive index layer 18, the decrease in scratch resistance is suppressed. Furthermore, from this viewpoint, the content of hollow silica particles in the low refractive index layer 18 is more preferably 45% by mass or less, and even more preferably 40% by mass or less, relative to 100% by mass of the solid content of the low refractive index layer 18.

[0096] Furthermore, the total amount of inorganic oxide particles and hollow silica particles in the low refractive index layer 18 is preferably 10% by mass or more and 50% by mass or less relative to 100% by mass of the solid content of the low refractive index layer 18. If the total amount of inorganic oxide particles and hollow silica particles in the low refractive index layer 18 is 10% by mass or more relative to 100% by mass of the solid content of the low refractive index layer 18, excellent scratch resistance can be obtained. Also from this viewpoint, the total amount of inorganic oxide particles and hollow silica particles in the low refractive index layer 18 is more preferably 20% by mass or more, and even more preferably 30% by mass or more, relative to 100% by mass of the solid content of the low refractive index layer 18. On the other hand, if the total amount of inorganic oxide particles and hollow silica particles in the low refractive index layer 18 is 50% by mass or less relative to 100% by mass of the solid content of the low refractive index layer 18, the low refractive index layer 18 can sufficiently retain inorganic oxide particles and hollow silica particles, thus providing excellent scratch resistance. Furthermore, from this viewpoint, the total amount of inorganic oxide particles and hollow silica particles in the low refractive index layer 18 is more preferably 48% by mass or less, even more preferably 46% by mass or less, and particularly preferably 43% by mass or less, based on 100% by mass of the solid content of the low refractive index layer 18.

[0097] Fluorine-containing compounds can function as antifouling agents. Furthermore, they improve the slipperiness of the surface of the low refractive index layer 18, thereby contributing to improved scratch resistance. Examples of fluorine-containing compounds include (meth)acrylates containing perfluoroalkyl groups. Such compounds include Shin-Etsu Chemical's "KY-1203," DIC's "Megafac RS-75," Daikin Industries' "Optool DAC-HP," and Neos' "Futergent 601AD." These fluorine-containing compounds can suppress the adhesion of dirt and fingerprints, and facilitate their removal.

[0098] The content of the fluorine-containing compound in the low refractive index layer 18 is preferably 1.0% by mass or more and 15.0% by mass or less based on 100% by mass of the solid content of the low refractive index layer 18. When the content of the fluorine-containing compound in the low refractive index layer 18 is 1.0% by mass or more based on 100% by mass of the solid content of the low refractive index layer 18, the slipperiness of the surface of the low refractive index layer 18 is improved, and scratch resistance is improved. In addition, stain resistance is improved. From this viewpoint, the content of the fluorine-containing compound in the low refractive index layer 18 is more preferably 2.0% by mass or more, and even more preferably 3.0% by mass or more, based on 100% by mass of the solid content of the low refractive index layer 18. Furthermore, when the content of the fluorine-containing compound in the low refractive index layer 18 is 15.0% by mass or less based on 100% by mass of the solid content of the low refractive index layer 18, the decrease in scratch resistance is suppressed. Furthermore, from this viewpoint, the content of the fluorine-containing compound in the low refractive index layer 18 is more preferably 13.0% by mass or less, even more preferably 10.0% by mass or less, and particularly preferably 5.0% by mass or less, based on 100% by mass of the solid content of the low refractive index layer 18.

[0099] The refractive index of the low refractive index layer 18 is not particularly limited as long as it is lower than that of the hard coat layer 14 and the high refractive index layer 16, but is preferably 1.35 or higher and 1.49 or lower. If the refractive index is 1.35 or higher, the strength of the low refractive index layer 18 can be made sufficient, and good scratch resistance can be obtained. On the other hand, if the refractive index is 1.49 or lower, the reflectivity of the anti-reflective film can be made even lower. From the above viewpoint, the refractive index of the low refractive index layer 18 is more preferably 1.38 or higher and 1.46 or lower, and even more preferably 1.40 or higher and 1.44 or lower.

[0100] The thickness of the low refractive index layer 18 is preferably in the range of 80 nm to 110 nm. More preferably 85 nm or more, and even more preferably 90 nm or more. Furthermore, it is more preferably 105 nm or less, and even more preferably 100 nm or less. Within this range, a good low luminous reflectance can be obtained, and light reflection can be reduced.

[0101] The low refractive index layer 18 can be formed using a composition comprising inorganic oxide particles, hollow silica particles, a fluorine-containing compound, and a binder resin. The fluorine-containing compound and the binder resin preferably have UV-reactive groups. Examples of UV-reactive groups include (meth)acryloyl groups. When the fluorine-containing compound and the binder resin have UV-reactive groups, the scratch resistance of the low refractive index layer 18 is improved, and the scratch resistance of the anti-reflective film 10 is improved. The composition for forming the low refractive index layer 18 preferably includes a photopolymerization initiator when the binder resin contains a UV-reactive group (UV-curable resin). The composition for forming the low refractive index layer 18 may also contain a solvent as needed. The binder resin of the low refractive index layer 18 may be composed of a UV-curable resin, a non-UV-curable resin, or a combination of a UV-curable resin and a non-UV-curable resin.

[0102] Examples of non-UV curable resins include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyester resins, polyether resins, polyolefin resins, and polyamide resins. Examples of thermosetting resins include unsaturated polyester resins, epoxy resins, alkyd resins, and phenolic resins.

[0103] Examples of photopolymerization initiators include alkylphenone-based, acylphosphine oxide-based, and oxime ester-based photopolymerization initiators. Examples of alkylphenone-based photopolymerization initiators include 2,2'-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl-ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropane-1- Examples include 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, and N,N-dimethylaminoacetophenone. Examples of acylphosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Examples of oxime ester-based photopolymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime). These photopolymerization initiators may be used individually or in combination of two or more.

[0104] The content of the photopolymerization initiator is preferably in the range of 0.1% by mass or more and 10% by mass or less, based on the total solid content of the composition for forming the low refractive index layer 18. More preferably, it is 1% by mass or more and 5% by mass or less.

[0105] Solvents used in the composition for forming the low refractive index layer 18 include alcohol-based solvents such as ethylene glycol monomethyl ether (EGM), propylene glycol monomethyl ether (PGM), and diethylene glycol monobutyl ether; ketone-based solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, and acetone; aromatic solvents such as toluene and xylene; and amide-based solvents such as N-methylpyrrolidone, acetamide, and dimethylformamide. These solvents may be used individually or in combination of two or more.

[0106] In addition, the low refractive index layer 18 may contain additives as needed. Examples of such additives include antifouling agents, dispersants, leveling agents, defoaming agents, vibration modifiers, antibacterial agents, flame retardants, slip agents, and refractive index modifiers.

[0107] (Method of manufacturing anti-reflective film) To manufacture the anti-reflective film 10, first, a composition for forming a hard coat layer 14 is applied to the surface of a base film 12, and after drying as necessary, it is cured by irradiation with ionizing radiation such as ultraviolet light to form a hard coat layer 14 on the surface of the base film 12. Then, a composition for forming a high refractive index layer 16 is applied to the surface of the hard coat layer 14, and after drying as necessary, it is cured by irradiation with ionizing radiation such as ultraviolet light. rays of light A high refractive index layer 16 is formed on the surface of the hard coat layer 14 by curing by irradiation. Furthermore, a composition for forming a low refractive index layer 18 is applied to the surface of the high refractive index layer 16, and if necessary, after drying, it is cured by irradiation with ionizing radiation such as ultraviolet light to form the low refractive index layer 18 on the surface of the high refractive index layer 16. By going through these steps, an anti-reflective film 10 can be manufactured.

[0108] When forming a hard coat layer 14 on the surface of the base film 12, the surface of the base film 12 may be subjected to a surface treatment before coating in order to improve the adhesion between the base film 12 and the hard coat layer 14. Examples of surface treatments include corona treatment, plasma treatment, hot air treatment, ozone treatment, and ultraviolet treatment.

[0109] The composition forming the hard coat layer 14, the composition forming the high refractive index layer 16, and the composition forming the low refractive index layer 18 can be coated using various coating methods such as reverse gravure coating, direct gravure coating, die coating, bar coating, wire bar coating, roll coating, spin coating, dip coating, spray coating, knife coating, and kiss coating, as well as various printing methods such as inkjet printing, offset printing, screen printing, and flexographic printing.

[0110] The drying process for each layer is not particularly limited as long as it removes the solvents used in the coating liquid, but it is preferable to carry it out at a temperature of 50 to 150°C for about 10 to 180 seconds.

[0111] For UV irradiation of each layer, high-pressure mercury lamps, electrodeless (microwave) lamps, xenon lamps, metal halide lamps, and other UV irradiation devices can be used. UV irradiation may be carried out under an inert gas atmosphere such as nitrogen, if necessary. The UV irradiation dose is not particularly limited, but is generally between 50 and 800 mJ / cm². 2 Preferably, 100-300 mJ / cm² 2 This is preferable.

[0112] (Characteristics of anti-reflective film) The arithmetic mean roughness Sa on the surface of the anti-reflective film 10, i.e., the surface of the low refractive index layer 18, is preferably 1.0 nm or more and 20 nm or less, from the viewpoint of good finger glide and scratch resistance. More preferably 3.0 nm or more, and even more preferably 5.0 nm or more. Also more preferably 15 nm or less, and even more preferably 10 nm.

[0113] The haze in the anti-reflective film 10 is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.2 or less, from the viewpoint of good transparency and other factors.

[0114] The luminous reflectance of the anti-reflective film 10 is preferably as low as possible, but is preferably 0.5% or less, more preferably 0.4% or less, and even more preferably 0.3% or less.

[0115] The anti-reflective film 10 having the above configuration comprises a base film 12, a hard coat layer 14 formed on the surface of the base film 12, a high refractive index layer 16 formed on the surface of the hard coat layer 14, and a low refractive index layer 18 formed on the surface of the high refractive index layer 16. The high refractive index layer 16 is composed of a cured product of an ionizing radiation curable composition containing a (meth)acrylate compound having a reactive group and titanium oxide particles surface-treated with a silane coupling agent having a reactive group. The average particle diameter (D50) of the titanium oxide particles on a volume basis is 20 nm or more, and the cumulative 90% particle diameter (D90) on a volume basis is 120 nm or less, thus providing high anti-reflective properties and excellent scratch resistance. The fact that the titanium oxide particles contained in the high refractive index layer 16 are surface-modified as described above and have a predetermined particle size distribution contributes to the improvement of anti-reflective properties and scratch resistance in the anti-reflective film 10. Although Patent Document 1 also states that titanium dioxide nanoparticles are contained in the high refractive index layer 16, the presence or absence of surface modification and the particle size distribution of these titanium dioxide nanoparticles are not clear.

[0116] <Other forms of anti-reflective film> As described above, the anti-reflective film according to the present invention is not limited to the configuration of the anti-reflective film 10 according to the first embodiment, as long as a hard coat layer 14, a high refractive index layer 16 having a predetermined composition, and a low refractive index layer 18 are laminated in this order on the surface of a base film 10. Other embodiments of the anti-reflective film according to the present invention are described below as examples.

[0117] (Second embodiment) Figure 2 shows an anti-reflective film 20 according to the second embodiment. The anti-reflective film 20 according to the second embodiment includes a base film 12, a hard coat layer 14 formed on the surface of the base film 12, a medium refractive index layer 15 formed on the surface of the hard coat layer 14, a high refractive index layer 16 formed on the surface of the medium refractive index layer 15, and a low refractive index layer 18 formed on the surface of the high refractive index layer 16. The anti-reflective film 20 has, in order from the base film 12 side, the base film 12, the hard coat layer 14, the medium refractive index layer 15, the high refractive index layer 16, and the low refractive index layer 18.

[0118] The anti-reflective film 20 according to the second embodiment differs from the anti-reflective film 10 according to the first embodiment in that it has a medium refractive index layer 15 between the hard coat layer 14 and the high refractive index layer 16. Otherwise, it is the same as the anti-reflective film 10 according to the first embodiment, and a description of the similar configuration will be omitted.

[0119] The medium refractive index layer 15 is a layer designed to exhibit a higher anti-reflective effect due to a significant refractive index difference between it and the high refractive index layer 16, and a significant refractive index difference between it and the low refractive index layer. The refractive index of the medium refractive index layer 15 is higher than that of the hard coat layer 14 and lower than that of the high refractive index layer 16. Furthermore, it is preferable that it is higher than that of the low refractive index layer 18.

[0120] The refractive index of the intermediate refractive index layer 15 is preferably in the range of 1.56 to 1.85 at a wavelength of 550 nm. More preferably it is 1.60 or higher, and even more preferably 1.65 or higher. Furthermore, it is even more preferably 1.80 or lower, and even more preferably 1.75 or lower. When the refractive index of the intermediate refractive index layer 15 is within the above range, the balance of interference arising from the refractive index difference between the intermediate refractive index layer 15 and the other layers can be optimized, and a higher anti-reflective effect can be obtained.

[0121] The thickness of the intermediate refractive index layer 15 is preferably in the range of 30 nm to 120 nm. More preferably it is 50 nm or more, and even more preferably 70 nm or more. Furthermore, it is more preferably 100 nm or less, and even more preferably 90 nm or less. By setting the thickness of the intermediate refractive index layer 15 within the above range, the anti-reflective function can be further enhanced.

[0122] The constituent materials of the medium refractive index layer 15 are not particularly limited, and any known materials conventionally used in anti-reflective films, etc., may be used to obtain a predetermined refractive index. For example, the materials usable in the hard coat layer 14 may be appropriately selected from the materials described above. Similarly, the materials usable in the high refractive index layer 16 may be appropriately selected from the materials described above. The refractive index of the medium refractive index layer 15 can be adjusted by selecting and blending the binder resin, inorganic oxide particles, and resin particles. For example, by reducing the content of inorganic oxide particles such as titanium oxide particles compared to the high refractive index layer 16, a medium refractive index layer 15 with a lower refractive index than the high refractive index layer 16 can be formed.

[0123] (Third embodiment) Figure 3 shows an anti-reflective film 30 according to the third embodiment. The anti-reflective film 30 according to the third embodiment includes a base film 12, a hard coat layer 14 formed on one surface of the base film 12, a high refractive index layer 16 formed on the surface of the hard coat layer 14, and a low refractive index layer 18 formed on the surface of the high refractive index layer 16. It also has a transparent adhesive layer 22 on the other surface of the base film 12. A release film 24 is placed on the surface of the transparent adhesive layer 22 as needed. The release film 24 functions as a protective layer for the transparent adhesive layer 22 before use of the anti-reflective film 30 and is peeled off from the transparent adhesive layer 22 when the anti-reflective film 30 is used.

[0124] The anti-reflective film 30 according to the third embodiment differs from the anti-reflective film 10 according to the first embodiment in that it has a transparent adhesive layer 22 on the other surface of the base film 12. Otherwise, it is the same as the anti-reflective film 10 according to the first embodiment, and a description of the similar configuration will be omitted.

[0125] The transparent adhesive layer 22 is for ensuring good adhesion of the anti-reflective film 30 to the surface of a display or the like. Furthermore, the presence of the transparent adhesive layer 22 of the anti-reflective film 30 has the effect of preventing the glass of the display or the like from shattering. In other words, the anti-reflective film 30 also functions as a shatterproof film.

[0126] The adhesive composition forming the transparent adhesive layer 22 may contain known adhesive resins such as acrylic adhesives, silicone adhesives, and urethane adhesives. Among these, acrylic adhesives are preferred from the viewpoint of optical transparency and heat resistance. The adhesive composition preferably contains a crosslinking agent to enhance the cohesive force of the transparent adhesive layer 22. Examples of crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, and chelate crosslinking agents.

[0127] The adhesive composition may contain additives as needed. Examples of known additives include plasticizers, silane coupling agents, surfactants, antioxidants, fillers, curing accelerators, and curing retarders. Furthermore, from the viewpoint of productivity, the composition may be diluted using organic solvents.

[0128] The thickness of the transparent adhesive layer 22 is not particularly limited, but is preferably in the range of 5 μm to 100 μm. More preferably it is 10 μm or more, and 50 μm or less.

[0129] The transparent adhesive layer 22 can be formed by methods such as directly applying the adhesive composition to the other surface of the base film 12, applying the adhesive composition to the surface of the release film 24 and then transferring it to the other surface of the base film 12, or applying the adhesive composition to the surface of the first release film, then bonding the second release film, peeling off one of the release films and transferring it to the other surface of the base film 12.

[0130] From the viewpoint of preventing glass from shattering, the transparent adhesive layer 22 preferably has an adhesive strength of 4N / 25mm or more to the glass. More preferably it is 6N / 25mm or more, and even more preferably 10N / 25mm or more.

[0131] (Fourth embodiment) Figure 4 shows an anti-reflective film 40 according to the fourth embodiment. The anti-reflective film 40 according to the fourth embodiment includes a base film 12, a hard coat layer 14 formed on one surface of the base film 12, a high refractive index layer 16 formed on the surface of the hard coat layer 14, a low refractive index layer 18 formed on the surface of the high refractive index layer 16, and a protective film 28 disposed on the surface of the low refractive index layer 18 via an adhesive layer 26.

[0132] The anti-reflective film 40 according to the fourth embodiment differs from the anti-reflective film 10 according to the first embodiment in that it has a protective film 28 on the surface of the low refractive index layer 18 via an adhesive layer 26. Otherwise, it is the same as the anti-reflective film 10 according to the first embodiment, and a description of the similar configuration will be omitted.

[0133] The protective film 28 can prevent scratches on the surface of the low refractive index layer 18 during handling, such as continuous processing in a roll process or lamination to a display. The protective film 28 is attached to the surface of the low refractive index layer 18 via an adhesive layer 26. After processing, the protective film 28 is peeled off from the surface of the low refractive index layer 18 together with the adhesive layer 26. For this reason, the adhesive force between the protective film 28 and the adhesive layer 26 is stronger than the adhesive force between the low refractive index layer 18 and the adhesive layer 26, and the adhesive force between the low refractive index layer 18 and the adhesive layer 26 is adjusted to allow for interfacial peeling.

[0134] The materials constituting the protective film 28 can be appropriately selected from those exemplified as materials constituting the base film 12. The thickness of the protective film 28 is not particularly limited, but can be in the range of 2 μm to 500 μm or 2 μm to 200 μm.

[0135] The adhesive forming the adhesive layer 26 is not particularly limited, and acrylic adhesives, silicone adhesives, urethane adhesives, etc., can be suitably used. Acrylic adhesives are particularly preferred because they have excellent transparency and heat resistance. The acrylic adhesive is preferably formed from an adhesive composition containing a (meth)acrylic polymer and a crosslinking agent.

[0136] (Meth)acrylic polymers are homopolymers or copolymers of (meth)acrylic monomers. Examples of (meth)acrylic monomers include alkyl group-containing (meth)acrylic monomers, carboxyl group-containing (meth)acrylic monomers, and hydroxyl group-containing (meth)acrylic monomers.

[0137] Examples of alkyl group-containing (meth)acrylic monomers include (meth)acrylic monomers having an alkyl group with 2 to 30 carbon atoms. The alkyl group with 2 to 30 carbon atoms may be linear, branched, or cyclic. More specifically, examples of alkyl group-containing (meth)acrylic monomers include isostearyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, decyl (meth)acrylate, isononyl (meth)acrylate, nonyl (meth)acrylate, isooctyl (meth)acrylate, octyl (meth)acrylate, isobutyl (meth)acrylate, n-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, propyl (meth)acrylate, ethyl (meth)acrylate, and methyl (meth)acrylate.

[0138] Examples of carboxyl group-containing (meth)acrylic monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate. The carboxyl group may be located at the terminal end of the alkyl chain or in the middle of the alkyl chain.

[0139] Examples of hydroxyl group-containing (meth)acrylic monomers include hydroxylauryl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxyethyl (meth)acrylate. The hydroxyl group may be located at the terminal end of the alkyl chain or in the middle of the alkyl chain.

[0140] The (meth)acrylic monomers that form the (meth)acrylic polymer may be any one of the above, or a combination of two or more.

[0141] Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, metal chelate-based crosslinking agents, metal alkoxide-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and melamine-based crosslinking agents. These crosslinking agents may be used individually or in combination of two or more.

[0142] The adhesive composition may contain other additives in addition to the (meth)acrylic polymer and crosslinking agent. Examples of other additives include crosslinking accelerators, crosslinking retarders, tackifiers, antistatic agents, silane coupling agents, plasticizers, release agents, pigments, dyes, wetting agents, thickeners, UV absorbers, preservatives, antioxidants, metal deactivators, alkylating agents, and flame retardants. These are selected and used appropriately depending on the application and intended use of the adhesive.

[0143] The thickness of the adhesive layer 26 is not particularly limited, but is preferably in the range of 1 μm to 10 μm. More preferably it is 2 μm or more, and 7 μm or less.

[0144] Although embodiments of the present invention have been described above, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0145] For example, in the above embodiment, it is stated that a surface treatment may be applied to the surface of the base film 12, but instead of surface treatment, an easy-adhesion layer may be provided on the surface of the base film 12.

[0146] In addition, in each of the above embodiments, an antifouling layer may be formed on the surface of the low refractive index layer 18 to further enhance its antifouling properties. When an antifouling layer is provided on the surface of the anti-reflective film 20, it is preferable that the refractive index difference between the low refractive index layer 18 and the antifouling layer be small from the viewpoint of reducing reflection at the interface. The refractive index of the antifouling layer is preferably 1.6 or less, and more preferably 1.55 or less. As the material of the antifouling layer, fluorine-containing silane compounds or fluorine-containing organic compounds are preferred. The antifouling layer can be formed by wet methods such as reverse coating, die coating, and gravure coating, or by dry processes such as vacuum deposition and CVD. The thickness of the antifouling layer is usually about 1 nm to 50 nm, preferably 2 nm to 30 nm, and more preferably 3 nm to 20 nm. Surface treatment may also be applied before forming the antifouling layer. Examples of surface treatments include corona treatment, plasma treatment, hot air treatment, ozone treatment, and ultraviolet treatment.

[0147] Furthermore, in the third embodiment described above, the transparent adhesive layer 22 and release film 24 are shown as being added to the anti-reflective film 10 of the first embodiment shown in Figure 1, as shown in Figure 3, but they may also be added to the anti-reflective film 20 of the second embodiment shown in Figure 2. Also, in the fourth embodiment described above, the adhesive layer 26 and protective film 28 are shown as being added to the anti-reflective film 10 of the first embodiment shown in Figure 1, as shown in Figure 4, but they may also be added to the anti-reflective film 20 of the second embodiment shown in Figure 2 or the anti-reflective film 30 of the third embodiment shown in Figure 3.

[0148] Furthermore, various functional layers, such as a gas barrier-enhancing layer, an antistatic layer, and an oligomer-blocking layer, may be pre-applied to the surface of the base film 12 before each layer is formed. The antistatic layer is provided for purposes such as reducing the adhesion of surrounding dust and other debris due to peeling charge or triboelectric charge. Preferably, the antistatic layer is made of an antistatic layer-forming composition containing an antistatic agent.

[0149] Examples of antistatic agents include cationic antistatic agents such as quaternary ammonium salts and pyridium salts, anionic antistatic agents such as alkali metal salts such as sulfonic acid, phosphoric acid, and carboxylic acid, amphoteric antistatic agents such as amino acid-based and amino acid sulfate ester-based agents, nonionic antistatic agents such as amino alcohol-based, glycerin-based, and polyethylene glycol-based agents, ionic compounds, conductive polymers such as polyacetylene-based and polythiophene-based agents, conductive particles such as metal oxide particles and carbon nanotubes, and conductive fibers. Among these, antistatic agents combining conductive polymers such as polyacetylene and polythiophene with dopants, metal particles, and metal oxide particles are preferred from the viewpoint of low humidity dependence and prevention of bleed-out from the antistatic layer.

[0150] Examples of conductive polymers constituting the antistatic agent include polyacetylene, polyaniline, polythiophene, polypyrrole, polyphenylene sulfide, poly(1,6-heptadiine), polybiphenylene (polyparaphenylene), polyparaphenylene sulfide, polyphenylacetylene, poly(2,5-thienylene), or derivatives thereof. Preferably, a polythiophene-based conductive organic polymer (e.g., 3,4-ethylenedioxythiophene (PEDOT)) is used. These may be used individually as antistatic agents or in combination of two or more.

[0151] The content of the antistatic agent is preferably in the range of 1% by mass or more and 50% by mass or less, based on the total solid content of the composition for forming the antistatic layer. If the content is 1% by mass or more, good antistatic properties can be provided. More preferably 5% by mass or more, and even more preferably 10% by mass or more. On the other hand, if the content is 50% by mass or less, a highly transparent film with good total light transmittance can be obtained. More preferably 40% by mass or less, and even more preferably 20% by mass or less.

[0152] The antistatic layer may contain a binder resin. The binder resin is not particularly limited as long as it is compatible with or can be mixed and dispersed with the antistatic agent, and may be a curable resin or a thermoplastic resin.

[0153] Examples of thermoplastic resins include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyimide resins such as polyimide and polyamide-imide; polyamide resins such as polyamide 6, polyamide 6,6, polyamide 12, and polyamide 11; polyvinylidene fluoride; acrylic resins; vinyl resins such as polyvinyl alcohol; and urethane resins. As the curable resin, the same material used when forming the hard coat layer 14 can be used.

[0154] The thickness of the antistatic layer is preferably 1 nm to 5 μm from the viewpoint of preventing static charge. More preferably 10 nm or more, and even more preferably 30 nm or more. Furthermore, it is more preferably 1 μm or less, and even more preferably 300 nm or less. [Examples]

[0155] The present invention will be described in detail below using examples and comparative examples. Unless otherwise specified, the preparation and evaluation of samples were carried out at room temperature in air.

[0156] <Preparation of compositions for forming a hard coat layer> To the UV-curable composition "Luxidia ESS-620" (manufactured by DIC, urethane acrylate resin, solvent: ethyl acetate, solids content: 79% by mass), the photopolymerization initiator "Omnirad127" (manufactured by IGM Resins BV, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one) was added at a concentration of 3% by mass relative to the total amount of the hard coat layer forming composition. Furthermore, ethyl acetate was added to bring the solids content to a total of 45% by mass to prepare the hard coat layer forming composition.

[0157] <Preparation of composition for forming an intermediate refractive index layer> A composition for forming a medium refractive index layer was prepared by blending the components so that the total solid content consisted of 46% by mass of UV-curable resin, 55% by mass of titanium dioxide particle dispersion, and 4% by mass of photopolymerization initiator, and then adjusting the solid content concentration to 3.9% by mass using a solvent (PGM).

[0158] The materials used as constituent components of the composition for forming the intermediate refractive index layer are as follows: ·UV curable resin - "Aronix MT-3041" manufactured by Toagosei Co., Ltd., polyfunctional acrylate, solid content concentration: 100% by mass • Titanium dioxide particle dispersion 1 - "LDB-102-45" manufactured by Ishihara Sangyo, containing titanium dioxide particles surface-treated with a silane coupling agent having a methacryloyl group and a dispersant, solvent: propylene glycol monomethyl ether (PGM), solids concentration: 45% by mass • Photopolymerization initiator - "Omnirad127" as described above.

[0159] <Preparation of compositions for forming high refractive index layers> Each component was blended to achieve the composition shown in Table 2 (unit: mass %) of the total solids, and then PGM was added to achieve the solids concentration shown in Table 2 to prepare a composition for forming a high refractive index layer.

[0160] The materials used as constituent components of the high refractive index layer forming composition are as follows: All titanium dioxide particles are of the rutile type. • UV-curing resin - "Arronix MT-3041" as described above. • Titanium dioxide particle dispersion 1 - "LDB-102-45" as described above • Titanium dioxide particle dispersion 2 - Ishihara Sangyo Co., Ltd. "LDB-102H-35", containing titanium dioxide particles surface-treated with a silane coupling agent having a methacryloyl group and a dispersant, solvent: PGM, solid content concentration: 35% by mass • Titanium dioxide particle dispersion 3 - "LDB-014" manufactured by Ishihara Sangyo, containing titanium dioxide particles surface-treated with a silane coupling agent having a methacryloyl group and a dispersant, solvent: PGM, solids concentration: 20% by mass • Titanium dioxide particle dispersion "RTTPGM20WT%-H30" manufactured by 4-CIK Nanotech, containing titanium dioxide particles and additives, solvent: propylene glycol monomethyl ether acetate (PGMEA), solids content: 20% by mass • Titanium dioxide particle dispersion "ELCOM TGX-21A" manufactured by 5-JGC Catalysts & Chemicals, containing titanium dioxide particles, tin oxide particles, and zirconium oxide particles surface-treated with a silane coupling agent having a methacryloyl group, solvent: PGM, solid content concentration: 20% by mass • Titanium dioxide particle dispersion 6-Teika "NS446", containing titanium dioxide particles, tin oxide particles, zirconium oxide particles, and amine, solvent: PGMEA, solid content concentration: 36% by mass • Titanium dioxide particle dispersion 7 - A mixture of the titanium dioxide particle dispersion 8 described below and the titanium dioxide particle dispersion 1 described above, in a mass ratio of 1:74, with a solid content concentration of 45% by mass. Titanium dioxide particle dispersion 8 contains titanium dioxide particles "SA-100" (manufactured by Teika) and two types of dispersants. As dispersants, "SN Dispersant 9228" (manufactured by Sunopco, a polyhydric alcohol-type nonionic surfactant) and "SN Sparse 70" (manufactured by Sunopco, a nonionic surfactant, aliphatic amide surfactant, diethanolamine) were added at a rate of 1 part by mass each per 100 parts by mass of SA-100. Furthermore, the solid content concentration was adjusted to 37% by mass using a solvent (PGM), and the mixture was dispersed using a homogenizer (1000 rpm, 10 minutes). • Photopolymerization initiator - "Omnirad127" as described above.

[0161] The presence or absence of surface modification with reactive group-containing silane coupling agents (SCAs), particle size, and content (in mass%) of each component of titanium dioxide particle dispersions 1 to 7 have been evaluated. The evaluation methods and results are summarized later.

[0162] <Preparation of a composition for forming a low refractive index layer> A composition for forming a low refractive index layer was prepared by blending the components so that, in terms of mass percent of the total solid content, it consisted of 47.1% by mass of UV-curable resin, 3.5% by mass of alumina sol, 8.2% by mass of fluorine-containing compound, 35.8% by mass of hollow silica particles, and 5.3% by mass of photopolymerization initiator. Furthermore, the solid content concentration was adjusted to 3% by mass using a solvent (MEK / PGM = 1 / 3).

[0163] The materials used as constituent components of the low refractive index layer formation composition are as follows: • UV-curing resin - "Arronix MT-3041" as described above. • Alumina sol - Toyo Chem's "RioDuras KT-110AL," 25% by mass of alumina particles (average particle size: 110 nm), 15% by mass of photosensitive monomer and resin, solvent (MEK, cyclohexanone, aliphatic solvent) • Fluorine-containing compound - Shin-Etsu Chemical Co., Ltd. "KY-1203", perfluoroalkyl group-containing (meth)acrylate, solvent: MIBK, solids content concentration: 20% by mass • Hollow silica particles - JGC Catalysts & Chemicals "Thru-Ria 4320", average particle size: 60 nm, solvent: MIBK, solids content concentration: 20% by mass • Photopolymerization initiator - "Omnirad127" as described above.

[0164] <Preparation of the hard coat layer> For each of Examples 1-3 and Comparative Examples 1-5, a hard coat layer-forming composition was applied to a base film (Toray Industries' "Lumirror #50-U403," polyethylene terephthalate film, 50 μm thick) using a #4 wire bar. After drying at 80°C for 3 minutes, light intensity of 80 mJ / cm² was applied using an electrodeless (microwave) lamp. 2 A hard coat layer was formed by irradiating it with ultraviolet light.

[0165] <Fabrication of the intermediate refractive index layer> For each of Examples 1-3 and Comparative Examples 1-5, the medium refractive index layer-forming composition was applied to the surface of the hard coat layer using a #4 wire bar, dried at 80°C for 60 seconds, and then exposed to light at an intensity of 150 mJ / cm using an electrodeless (microwave) lamp. 2 A medium refractive index layer was formed by irradiating it with ultraviolet light.

[0166] <Fabrication of high refractive index layers> For each of Examples 1-3 and Comparative Examples 1-5, the high refractive index layer-forming composition was applied to the surface of the medium refractive index layer using a #4 wire bar, dried at 80°C for 60 seconds, and then exposed to light at an electrodeless (microwave) lamp with a light intensity of 150 mJ / cm². 2 A high refractive index layer was formed by irradiating it with ultraviolet light.

[0167] <Fabrication of low refractive index layers> For each of Examples 1-3 and Comparative Examples 1-5, the low refractive index layer-forming composition was applied to the surface of the high refractive index layer using a #4 wire bar, dried at 80°C for 60 seconds, and then exposed to light at an electrodeless (microwave) lamp with a light intensity of 150 mJ / cm². 2 A low refractive index layer was formed by irradiating it with ultraviolet light. Based on the above, an anti-reflective film was fabricated.

[0168] <Evaluation Method> (Particle size of titanium dioxide particles) Titanium dioxide particle dispersions 1 to 7 were each adjusted in concentration by adding PGM to achieve a solid content concentration of 10% by mass. Using a nanoparticle size measurement system (Otsuka Electronics "nanoSAQLA"), the volume-based average particle size (D50), volume-based cumulative 90% particle size (D90), and volume-based cumulative 10% particle size (D10) were measured by dynamic light scattering. The polydispersity index (PDI) of the titanium dioxide particles was also calculated according to the following formula (1). PDI = (D90 - D10) / D50 (1)

[0169] (Composition of titanium dioxide particle dispersion) One g of each of the titanium oxide particle dispersions 1 to 7 was placed on an aluminum petri dish and immersed in a 100°C constant temperature bath for one hour to allow volatile components to evaporate. The weight ratio of the elements contained in the titanium oxide particle film was measured on the surface using energy-dispersive X-ray spectroscopy with a scanning electron microscope (JEOL JCM-7000).

[0170] (Thickness and refractive index of each layer) The thickness and refractive index of each layer—hard coat layer, medium refractive index layer, high refractive index layer, and low refractive index layer—were evaluated. For each layer formed, the reflection spectral data in the wavelength range of 380-780 nm obtained using a micro-spectrometer (OPTM-F1, manufactured by Otsuka Electronics) and the theoretical spectrum derived based on Fresnel's equation were curve-fitted using the least squares method to calculate the thickness of each layer and the refractive index at 550 nm.

[0171] (Scratch resistance) A flat abrasion tester (DAS-400, manufactured by Daiei Kagaku Seiki Seisakusho) was used to test steel wool #0000 (manufactured by Nippon Steel Wool Co., Ltd.), fixed to a 20mm x 20mm flat abrasive, on the surface of the low refractive index layer of an anti-reflective film, which was then moved back and forth. The stroke length of the test stand was 50mm, the reciprocating speed of the test stand was 60 reciprocations / minute, and the test was performed 1500 times with a load of 1.0kg. After the test, the anti-reflective film was visually inspected and evaluated according to the following criteria. A: No scratches are visible at all, and the scratch resistance is very high. B: There are scratches less than 10mm in length, but no scratches longer than 10mm, and it has sufficient scratch resistance for practical use. C: There are 1 to 9 scratches longer than 10mm, indicating low scratch resistance. D: There are 10 or more scratches that are 10mm or longer, indicating very low scratch resistance.

[0172] (Haze (Hz)) The haze (Hz) of the entire anti-reflective film was measured using the "Haze Meter NDH7000" manufactured by Nippon Denshoku Industries, according to the JIS-K7136 method. A haze of 2.0 or less indicates high transparency.

[0173] (Visual reflectance) The back surface of the fabricated anti-reflective film (the side opposite the low refractive index layer) was roughened with #400 grit sandpaper and painted black. The 5° specular reflectance of the surface of the low refractive index layer at wavelengths of 380 nm to 780 nm was measured using a UV-Vis-Near-Infrared spectrophotometer (Shimadzu Corporation "UV-3600"). The luminous reflectance was calculated by multiplying this measurement by the relative luminous efficiency value. If the luminous reflectance is 0.5% or less, the anti-reflective properties can be considered sufficient.

[0174] <Evaluation Results> Table 1 shows the evaluation results for the composition of titanium dioxide particle dispersions 1 to 7 used to form the high refractive index layer. Table 2 shows the evaluation results for Examples 1 to 3 and Comparative Examples 1 to 5, along with the component composition of the high refractive index layer and the thickness of each layer. In Table 2, "Titanium dioxide content (relative to solids)" is the amount calculated based on the Ti content in the composition of the titanium dioxide particle dispersions in Table 1, the solids concentration of each dispersion, and the composition of the high refractive index layer in Table 2.

[0175] [Table 1]

[0176] [Table 2]

[0177] In the curable compositions constituting the high refractive index layer, Comparative Examples 1 and 2, where the titanium oxide particles are not surface-treated with a silane coupling agent having a reactive group, exhibit poor scratch resistance.

[0178] In Comparative Examples 3 and 4, the D50 of the titanium dioxide particles in the high refractive index layer is less than 20 nm. In these samples, the luminous reflectance exceeds 0.5%. In the high refractive index layer, the D50 of the titanium dioxide particles is too small, making it impossible to disperse titanium dioxide at a high concentration in the titanium dioxide particle dispersion (see the Ti content in the composition in Table 1), and thus the titanium dioxide particles contained in the high refractive index layer could not be made at a sufficient concentration (see the titanium dioxide content in Table 2). Therefore, it is interpreted that the refractive index of the high refractive index layer is insufficient. Furthermore, in Comparative Example 4, the titanium dioxide particles in the curable composition constituting the high refractive index layer are not surface-treated with a silane coupling agent having a reactive group, resulting in poor scratch resistance.

[0179] In Comparative Example 5, the haze value, which indicates low transparency, is large, corresponding to the D90 of the titanium oxide particles in the high refractive index layer exceeding 120 nm.

[0180] Unlike these comparative examples, in Examples 1-3, the titanium oxide particles contained in the curable composition constituting the high refractive index layer are surface-treated with a silane coupling agent having a reactive group, and have a D50 of 20 nm or more and a D90 of 120 nm or less. Correspondingly, high scratch resistance, rated as A, was obtained in all three Examples 1-3. Furthermore, high anti-reflective properties, indicated by a luminous reflectance of 0.5% or less, and high transparency, indicated by a haze of 2.0 or less, were also obtained.

[0181] As described above, the anti-reflective film comprises a base film, a hard coat layer formed on the surface of the base film, a high refractive index layer formed on the surface of the hard coat layer, and a low refractive index layer formed on the surface of the high refractive index layer. The high refractive index layer is composed of a cured product of an ionizing radiation-curable composition containing a (meth)acrylate compound having a reactive group and titanium oxide particles surface-treated with a silane coupling agent having a reactive group capable of bonding with the (meth)acrylate compound. The volume-based average particle diameter (D50) of the titanium oxide particles is 20 nm or more, and the volume-based cumulative 90% particle diameter (D90) is 120 nm or less. As a result, the contribution of the high refractive index layer provides an anti-reflective film with high anti-reflective properties and excellent scratch resistance.

[0182] Although embodiments of the present invention have been described above, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. [Explanation of Symbols]

[0183] 10, 20, 30, 40 Anti-reflective film 12. Base film 14. Hard court layer 15 Intermediate refractive index layer 16 High refractive index layer 18 Low refractive index layer 22 Transparent adhesive layer 24 Release film 26 Adhesive layer 28 protective films

Claims

1. It comprises a base film, a hard coat layer formed on the surface of the base film, a high refractive index layer formed on the surface of the hard coat layer, and a low refractive index layer formed on the surface of the high refractive index layer. The high refractive index layer is composed of a cured product of an ionizing radiation-curable composition containing a (meth)acrylate compound having a reactive group and titanium oxide particles surface-treated with a silane coupling agent having a reactive group capable of bonding with the (meth)acrylate compound. The average particle diameter D50 in the volume-based cumulative particle size distribution of the titanium oxide particles is 20 nm or more, and the 90% particle diameter D90 in the volume-based cumulative particle size distribution is 120 nm or less. The polydispersity index PDI, expressed as (D90 - D10) / D50, is 3.0 or less, where D10 is the 10% particle size in the volume-based cumulative particle size distribution of the titanium oxide particles. The content of the titanium oxide particles in the entire high refractive index layer is 45% by mass or more and 80% by mass or less based on 100% by mass of the solid content of the high refractive index layer. Anti-reflective film with a haze level of 2.0 or less.

2. The refractive index of the high refractive index layer at a wavelength of 550 nm is 1.83 or higher and 2.00 or lower. The anti-reflective film according to claim 1, wherein the refractive index of the low refractive index layer at a wavelength of 550 nm is 1.35 or more and 1.49 or less.

3. The anti-reflective film according to claim 1 or claim 2, wherein a medium refractive index layer is provided between the hard coat layer and the high refractive index layer, the medium refractive index layer having a refractive index at a wavelength of 550 nm that is higher than the refractive index of the hard coat layer and lower than the refractive index of the high refractive index layer.

4. The titanium oxide particles are The average particle diameter D50 is 20 nm or more and 100 nm or less. The 90% particle size D90 is 50 nm or more and 120 nm or less. The anti-reflective film according to claim 1 or claim 2, wherein the 10% particle size D10 is 10 nm or more and 40 nm or less.

5. The anti-reflective film according to claim 1 or claim 2, wherein the average particle diameter D50 of the titanium oxide particles is 20 nm or more and 60 nm or less.

6. A hard coat layer is formed on the surface of the base film. A high refractive index layer is formed by applying an ionizing radiation-curable composition containing a (meth)acrylate compound having a reactive group and a particle dispersion in which titanium oxide particles surface-treated with a silane coupling agent having a reactive group capable of bonding with the (meth)acrylate compound are dispersed in a solvent. A method for manufacturing an anti-reflective film according to claim 1 or claim 2, comprising forming a low refractive index layer on the surface of the high refractive index layer, A method for manufacturing an anti-reflective film, wherein the content of titanium atoms in the particle dispersion is 40% by mass or more and 80% by mass or less, relative to 100% by mass of the total solid content.

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