Anti-reflective film and active energy ray curable composition

Abstract

To provide an anti-reflective film having superior scratch resistance compared to conventional films, and an active energy ray curable composition for obtaining the anti-reflective film that exhibits excellent temporal stability. [Solution] An anti-reflective film having a laminated structure in which a light-transmitting substrate, a high refractive index layer (α), and a low refractive index layer (β) are arranged in this order, wherein the high refractive index layer (α) is a cured product of an active energy ray curable composition, and the active energy ray curable composition comprises a compound (A) having three or more (meth)acryloyl groups, a compound (B) having a silsesquioxane skeleton, metal oxide particles (C) with a refractive index of 1.70 to 2.72, and a photopolymerization initiator (D). (However, compound (A) excludes compound (B).)

Description

Technical Field

[0001] The present invention relates to an antireflection film having a laminated structure in which a light-transmissive substrate, a high refractive index layer (α), and a low refractive index layer (β) are arranged in this order, and an active energy ray-curable composition for forming the high refractive index layer (α).

Background Art

[0002] On the image display surface of image display devices such as liquid crystal displays, organic EL displays, and touch panels of smartphones, an antiglare film or an antireflection film is provided to suppress the reflection of external light.

[0003] An antireflection film reduces the reflectance by the interference effect of light reflected on the surface of the low refractive index layer and light reflected at the interface between the low refractive index layer and the layer adjacent to the low refractive index layer (for example, a hard coat layer or a high refractive index layer).

[0004] An antireflection film is often laminated on the outermost layer of a display, and scratch resistance and abrasion resistance are required.

[0005] As methods for exhibiting high scratch resistance, increasing the film hardness, forming surface irregularities, increasing the adhesion between layers, etc. are known.

[0006] In Patent Document 1, a specific monomer having an isocyanate group is used in the composition for forming the high refractive index layer to improve the adhesion between the high refractive index layer and the low refractive index layer, thereby improving the scratch resistance. However, the scratch resistance of Patent Document 1 is insufficient, and higher scratch resistance is required. Further, in the composition of Patent Document 1, when a large amount of a monomer having an isocyanate group is blended, the high refractive index particles tend to aggregate and sediment, and there is a problem in the stability of the composition over time.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

[0008] The present invention aims to provide an anti-reflective film having a laminated structure in which a light-transmitting substrate, a high refractive index layer (α), and a low refractive index layer (β) are arranged in that order, and which has superior scratch resistance compared to conventional films, and an active energy ray curable composition for obtaining the anti-reflective film that has excellent temporal stability. [Means for solving the problem]

[0009] The inventors of this invention have conducted extensive research to solve the above problems and have arrived at the following invention. The present invention provides the following anti-reflective film and active energy ray curable composition. <1>: An anti-reflective film having a laminated structure in which a light-transmitting substrate, a high refractive index layer (α), and a low refractive index layer (β) are arranged in this order, wherein the high refractive index layer (α) is a cured product of an active energy ray curable composition, and the active energy ray curable composition comprises a compound (A) having three or more (meth)acryloyl groups, a compound (B) having a silsesquioxane skeleton, metal oxide particles (C) with a refractive index of 1.70 to 2.72, and a photopolymerization initiator (D). (However, compound (A) excludes compound (B).) (2) The anti-reflective film, characterized in that the metal oxide particles (C) include one or more selected from the group consisting of zirconium oxide particles, titanium oxide particles, and aluminum oxide particles. (3) The anti-reflective film characterized in that the low refractive index layer (β) contains hollow particles. <4> The anti-reflective film characterized in that the low refractive index layer (β) contains inorganic oxide fine particles. <5>: The anti-reflective film characterized in that the compound (B) having a silsesquioxane skeleton contains a compound (b1) having a silsesquioxane skeleton and a (meth)acryloyl group. <6>: The anti-reflective film characterized in that the compound (A) contains a compound (a1) having eight or more (meth)acryloyl groups. <7> The anti-reflective film characterized in that the minimum value of the reflectance measured at an incident angle of 5° in the wavelength range of 380 to 780 nm is 2% or less. <8>: An active energy ray curable composition for forming a high refractive index layer (α) in the anti-reflective film. [Effects of the Invention]

[0010] The present invention makes it possible to provide an anti-reflective film with superior scratch resistance compared to conventional films, and an active energy ray curable composition for obtaining the anti-reflective film with excellent temporal stability. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view partially showing the anti-reflective film (without hard coat layer) of the present invention. [Figure 2] This is a schematic cross-sectional view partially showing the anti-reflective film (with hard coat layer) of the present invention. [Modes for carrying out the invention]

[0012] The present invention will be described in detail below. In this specification, unless otherwise specified, the term "(meth)acryloyl" refers to "acryloyl or methacryloyl". In addition, the "compound (A) having three or more (meth)acryloyl groups" may be referred to as "compound (A)", the "compound (a1) having eight or more (meth)acryloyl groups" may be referred to as "compound (a1)", the "compound (B) having a silsesquioxane skeleton" may be referred to as "compound (B)", the "compound (b1) having a silsesquioxane skeleton and a (meth)acryloyl group" may be referred to as "compound (b1)", and the "metal oxide particles (C) having a refractive index of 1.70 to 2.72" may be referred to as "metal oxide particles (C)". Unless otherwise noted, each main component appearing in this specification may be used independently alone or as a mixture of two or more components.

[0013] In this specification, the numerical range specified using "~" shall include the numerical values described before and after "~" as the range of the lower limit value and the upper limit value.

[0014] [Anti-reflection film] The anti-reflection film of the present invention is a laminate in which a light-transmissive substrate, a high refractive index layer (α), and a low refractive index layer (β) are arranged in this order. As long as the light-transmissive substrate, the high refractive index layer (α), and the low refractive index layer (β) are arranged in this order, the anti-reflection film may further have another cured film layer such as a hard coat layer or an optical adjustment layer therebetween.

[0015] From the viewpoint of anti-reflection performance, it is preferable that the minimum value of the reflectance measured at an incident angle of 5° in the wavelength range of 380 to 780 nm of the anti-reflection film is 2% or less. More preferably, it is 1.5% or less, and particularly preferably 1.0% or less.

[0016] In order to obtain good reflectance from the light interference effect with other interfaces, the film thicknesses of the high refractive index layer (α) and the low refractive index layer (β) are preferably 50 to 150 nm, and more preferably 70 to 140 nm.

[0017] ≪Light-transmissive substrate≫ The light-transmissive substrate is not particularly limited as long as it has light transmittance, and examples thereof include glass, synthetic resin moldings, films, etc. The substrate thickness is not particularly limited, but is usually about 25 to 200 μm.

[0018] Examples of the synthetic resin molding include moldings of synthetic resins such as polymethyl methacrylate resin, copolymer resin having methyl methacrylate as a main component, polystyrene resin, styrene-methyl methacrylate copolymer resin, styrene-acrylonitrile copolymer resin, polycarbonate resin, cellulose acetate butyrate resin, polyallyl diglycol carbonate resin, polyvinyl chloride resin, polyester resin, etc.

[0019] Examples of the film include polyester film, polyethylene film, polypropylene film, cellophane film, diacetyl cellulose film, triacetyl cellulose (TAC) film, acetyl cellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, polyolefin film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether ether ketone film, polyether sulfone film, polyether imide film, polyimide film, fluororesin film, nylon film, acrylic film, etc.

[0020] ≪High refractive index layer (α)≫ The antireflection film of the present invention includes a high refractive index layer (α) which is a cured product of an active energy ray-curable composition.

[0021] The refractive index of the high refractive index layer (α) is not particularly limited as long as it is higher than that of the low refractive index layer (β), but is preferably 1.55 to 1.90 at a wavelength of 594 nm. More preferably it is 1.60 to 1.90. If the refractive index is less than 1.55, the refractive index of the low refractive index layer must be drastically reduced in order to make the anti-reflective film low-reflectance, which worsens scratch resistance. If it is greater than 1.90, the amount of metal oxide particles increases and the amount of binder component decreases, which worsens scratch resistance.

[0022] <Active energy ray curable composition> An active energy ray curable composition comprises a compound (A) having three or more (meth)acryloyl groups, a compound (B) having a silsesquioxane skeleton, metal oxide particles (C) with a refractive index of 1.70 to 2.72, and a photopolymerization initiator (D). By forming a high refractive index layer (α) using such an active energy ray curable composition, adhesion to the low refractive index layer is improved, making it possible to provide an anti-reflective film with excellent scratch resistance.

[0023] (Compound (A)) Compound (A) is a compound having three or more (meth)acryloyl groups. Specifically, trimethylolpropane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tetramethylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl) isocyanurate, caprolactone-modified tris(acryloxyethyl) isocyanurate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, alkyl-modified dipentaerythritol tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, ethylene oxide-modified glycerol tri(meth)acrylate, propylene oxide-modified glycerol tri(meth)acrylate, ε-caprolactone-modified trimethylolpropane Examples of monomers having three or more (meth)acryloyl groups include, but are not limited to, (meth)acrylate, pentaerythritol tri(meth)acrylate, dimethylolpropanetetra(meth)acrylate, ethylene oxide-modified dimethylolpropanetetra(meth)acrylate, prolene oxide-modified dimethylolpropanetetra(meth)acrylate, tetramethylene oxide-modified dimethylolpropanetetra(meth)acrylate, ditrimethylolpropanetetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, alkyl-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0024] Furthermore, oligomers having three or more (meth)acryloyl groups can also be used. Examples include urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and acrylic resin (meth)acrylate. Compound (A) may be used alone or in combination of two or more compounds.

[0025] Compound (A) is broadly classified into two types: compound (a1) having eight or more (meth)acryloyl groups, and compound (a2) having three to seven (meth)acryloyl groups. It is preferable to include compound (a1) having eight or more (meth)acryloyl groups. By including compound (a1), the hardness of the high refractive index layer is increased, and an anti-reflective film with excellent scratch resistance can be obtained.

[0026] Examples of commercially available compounds (a1) having eight or more (meth)acryloyl groups include, but are not limited to, UN-952 manufactured by Negami Kogyo Co., Ltd., U-10PA manufactured by Shin Nakamura Chemical Industry Co., Ltd., Shiko UV-1700B manufactured by Mitsubishi Chemical Corporation, and MIRAMER MU9500 manufactured by MIWON Corporation. Examples of commercially available compounds (a2) having 3 to 7 (meth)acryloyl groups include, but are not limited to, MIRAMER M300, MIRAMER M500, MIRAMER M600, and MIRAMER PU610 from MIWON Corporation, and KAYARAD DPHA and KAYARAD PET30 from Nippon Kayaku Co., Ltd.

[0027] From the viewpoint of achieving both scratch resistance and a high refractive index, the content of compound (A) is preferably 10 to 90% by mass, and more preferably 20 to 85% by mass, of 100% by mass of the nonvolatile content of the active energy ray curable composition for forming the high refractive index layer (α).

[0028] (Compound (B)) Compound (B) is a compound having a silsesquioxane skeleton. When compound (B) is included in an active energy ray curable composition, the rigid skeleton of silsesquioxane provides good hardness, and the interaction with oxygen atoms and some remaining silanol groups results in good adhesion to the low refractive index layer, thus exhibiting excellent scratch resistance in anti-reflective films. Furthermore, because compound (B) has low reactivity with particle dispersants and surface treatment agents, particle aggregation does not occur even when a large amount is added to the system to improve adhesion to the low refractive index layer, thus achieving both the long-term stability and adhesion of the composition.

[0029] Compound (B) is not particularly limited as long as it is a network polymer or polyhedral cluster structure having the structure of (RSiO1.5)n obtained by hydrolysis and condensation of silsesquioxane, i.e., a trifunctional silane. Compounds having a silsesquioxane skeleton with known and conventional structures such as random structure, ladder structure, complete cage structure, and incomplete cage structure can be used. In (RSiO1.5)n, n is an integer of 2 or more. Preferably, n is an integer from 2 to 200, more preferably from 2 to 150, and even more preferably from 2 to 100. In addition, in (RSiO1.5)n, R is preferably an organic group such as a methyl group, ethyl group, phenyl group, or (meth)acryloyl group.

[0030] Compound (B) preferably contains compound (b1) having a silsesquioxane skeleton and (meth)acryloyl groups, wherein at least a portion of R in (RSiO1.5)n is a (meth)acryloyl group. The (meth)acryloyl group of compound (b1) improves adhesion to the low refractive index layer. Furthermore, if a compound has a silsesquioxane skeleton, it is classified as compound (B) even if it has three or more (meth)acryloyl groups.

[0031] Examples of compounds (b1) having a silsesquioxane skeleton and a (meth)acryloyl group include AC-SQ TA-100, MAC-SQ TM-100, AC-SQ SI-20, MAC-SQ ST-20, and MAC-SQ HDM, all manufactured by Toagosei Co., Ltd. Examples of commercially available compounds (b2) having a silsesquioxane skeleton where R is not a (meth)acryloyl group include SR-21, SR-23, SR-13, SR-33, and SO-04 from Konishi Chemical Industry Co., Ltd., SQ107, SQ109, and SQ506 from Arakawa Chemical Industries, Ltd., and OX-SQ TX-100, OX-SQ SI-20, and OX-SQH DX from Toagosei Co., Ltd.

[0032] The content of compound (B) having a silsesquioxane skeleton is more preferably 0.1 to 60% by mass of 100% by mass of the nonvolatile content of the active energy ray curable composition for forming the high refractive index layer (α), from the viewpoint of achieving both scratch resistance and a high refractive index, and even more preferably 3 to 50% by mass to suppress the aggregation of metal oxides. This content is preferable because it allows for good adhesion with the low refractive index layer while maintaining the refractive index.

[0033] (Metal oxide particles (C)) The metal oxide particles (C) are metal oxide particles with a refractive index of 1.70 to 2.72. These may be used individually as optically adjustable metal oxide particles, or in combination of two or more types.

[0034] Examples of metal oxide particles (C) include metal oxide particles made from metal oxides such as titanium, zirconium, tin, zinc, niobium, aluminum, chromium, magnesium, germanium, gallium, and antimony. From the viewpoint of achieving both high refractive index and transparency, it is preferable to include one or more particles selected from the group consisting of zirconium oxide particles (refractive index 2.17), titanium oxide particles (refractive index 2.71), and aluminum oxide particles (refractive index 1.76). It is more preferable to include zirconium oxide particles or aluminum oxide particles, and it is particularly preferable to include zirconium oxide particles.

[0035] Examples of commercially available metal oxide particles (C) include Zircostar ZP-153 and Zircostar HR-101 from Nippon Shokubai Co., Ltd., SZR-K from Sakai Chemical Industry Co., Ltd., and NS405 and NS408 from Teika Co., Ltd.

[0036] The content of metal oxide particles (C) is preferably 5 to 90% by mass, more preferably 20 to 80% by mass, and most preferably 40 to 65% by mass, of 100% by mass of the nonvolatile content of the active energy ray curable composition for forming the high refractive index layer (α), from the viewpoint of achieving both refractive index and scratch resistance.

[0037] (Photopolymerization initiator (D)) Examples of photopolymerization initiators (D) that can be used include monocarbonyl photopolymerization initiators, dicarbonyl photopolymerization initiators, acetophenone photopolymerization initiators, benzoin ether photopolymerization initiators, acylphosphine oxide photopolymerization initiators, and aminocarbonyl photopolymerization initiators. The photopolymerization initiator (D) may be used in combination with the sensitizer.

[0038] For example, monocarbonyl photopolymerization initiators such as benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, methyl-o-benzoylbenzoate, 4-phenylbenzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2- / 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1-chloro-4-propoxythioxanthone; Dicarbonyl photopolymerization initiators such as 2-ethylanthraquinone, 9,10-phenanthrenequinone, and methyl-α-oxobenzene acetate; Acetophenone-based photopolymerization initiators such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, diethoxyacetophenone, dibutoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,2-diethoxy-1,2-diphenylethane-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, and 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime; Benzoin ether-based photopolymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzoin n-butyl ether; Acylphosphine oxide-based photopolymerization initiators such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 4-n-propylphenyl-di(2,6-dichlorobenzoyl)phosphine oxide; Furthermore, aminocarbonyl photopolymerization initiators such as ethyl-4-(dimethylamino)benzoate, 2-n-butoxyethyl-4-(dimethylamino)benzoate, isoamyl-4-(dimethylamino)benzoate, 2-(dimethylamino)ethylbenzoate, 4,4'-bis-4-dimethylaminobenzophenone, 4,4'-bis-4-diethylaminobenzophenone, and 2,5'-bis(4-diethylaminobenzal)cyclopentanone; These are some examples.

[0039] Commercially available photopolymerization initiators (D) include Omnirad 184, 651, 500, 907, 127, 369, 784, and 2959 from IGM-Resins BV, as well as Esacure One and Lucilin TPO from BASF. Omnirad 184 is particularly preferred in terms of resistance to yellowing after active energy ray curing.

[0040] The content of the photopolymerization initiator (D) is not limited as long as it contains enough to cure the active energy ray curable composition to the desired physical properties by ultraviolet light. However, from the viewpoint of curing speed, hardness, and scratch resistance, it is preferably 1 to 15% by mass, and more preferably 3 to 10% by mass, of 100% by mass of the nonvolatile content of the active energy ray curable composition.

[0041] (solvent) The active energy ray curable composition of this embodiment may contain a solvent as needed. If a solvent is added, it is preferable to perform the curing treatment with active energy rays after the solvent has evaporated.

[0042] The solvent is not particularly limited, and various known organic solvents can be used. Specifically, examples include cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, acetone, acetylacetone, toluene, xylene, n-butanol, isobutanol, tert-butanol, n-propanol, isopropanol, ethanol, methanol, 3-methoxy-1-butanol, 3-methoxy-2-butanol, ethylene glycol monomethyl ether, ethylene glycol mono-n-butyl ether, 2-ethoxyethanol, 1-methoxy-2-propanol, diacetone alcohol, ethyl lactate, butyl lactate, propylene glycol monomethyl ether, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 2-ethoxyethyl acetate, butyl acetate, isoamyl acetate, dimethyl adipate, dimethyl succinate, dimethyl glutarate, tetrahydrofuran, methylpyrrolidone, etc. Two or more of these organic solvents may be used in combination.

[0043] (Other components (E)) Furthermore, other components not listed above may be included, as long as they do not impair the purpose or effects of the present invention. Examples include (meth)acrylate compounds other than compound (A), surfactants, colorants, stabilizers, resins, surface treatment agents, viscosity modifiers, adhesion promoters, antioxidants, anti-aging agents, crosslinking accelerators, UV absorbers, plasticizers, preservatives, dispersants, defoamers, silane coupling agents, and inorganic fillers.

[0044] ≪Low refractive index layer (β)≫ The low refractive index layer (β) is formed using a composition for forming the low refractive index layer. The low refractive index layer (β) preferably contains hollow particles because it has excellent foldability and can maintain a low reflectivity. From the viewpoint of scratch resistance, it is even more preferable to include inorganic oxide fine particles (excluding hollow particles).

[0045] <Composition for forming a low refractive index layer> The composition for forming the low refractive index layer (β) is not particularly limited as long as it is a known composition that has been used in anti-reflective films and the like in the past, but it is preferable that it is an active energy ray curable composition in terms of productivity. As mentioned above, it is preferable that it contains hollow particles and inorganic oxide fine particles (excluding hollow particles).

[0046] Hollow particles are particles that have voids inside. Their hollow structure allows them to lower the refractive index of the low-refractive-index layer, thereby reducing light reflection. Examples of hollow particles include hollow silica particles and hollow polymer particles. The size of the hollow particles is not particularly limited, as long as it is within the particle size generally used in compositions for forming low-refractive-index layers.

[0047] Examples of commercially available hollow particles include JGC Catalysts & Chemicals' Thru-Ria 4320 and Sekisui Chemicals' Techpolymer XX5964Z.

[0048] Inorganic oxide nanoparticles form protrusions on the surface of low refractive index layers, and these protrusions provide good scratch resistance. Examples of inorganic oxide nanoparticles include aluminum oxide and silica. Even if inorganic oxide nanoparticles are hollow, they are classified as hollow particles. The inorganic oxide fine particles are not particularly limited, as long as they have a particle size commonly used in compositions for forming low refractive index layers.

[0049] Examples of commercially available inorganic oxide nanoparticles include NANOBYK3610 from Big Chem Japan and RioDuras KT-110AL from Toyo Chem Co., Ltd.

[0050] The content of the hollow particles is preferably 10 to 95% by mass of 100% by mass of the nonvolatile content of the composition for forming the low refractive index layer (β) in order to achieve both refractive index reduction and scratch resistance. More preferably it is 15 to 60% by mass, and even more preferably 25 to 40% by mass.

[0051] The content of the inorganic oxide fine particles is preferably 0.1 to 5% by mass of 100% by mass of the nonvolatile content of the composition for forming the low refractive index layer (β), in order to achieve both a reduction in refractive index and scratch resistance.

[0052] The refractive index of the low refractive index layer (β) is not particularly limited as long as it is lower than that of the high refractive index layer (α), but from the viewpoint of anti-reflection, it is preferably 1.20 to 1.45 at a wavelength of 594 nm. More preferably it is 1.30 to 1.45.

[0053] ≪Method for manufacturing anti-reflective film≫ The anti-reflective film of the present invention can be formed by the following methods, but is not limited thereto. For example, various coating methods such as using a rod, wire bar, microgravure, gravure, die, curtain, lip, slot, or spin can be used. After forming a coating film of the composition for forming the high refractive index layer (α), it is allowed to dry naturally or by forced drying. Then, the high refractive index layer (α) is obtained by curing by irradiation with active energy rays. Subsequently, after forming a coating film of the composition for forming the high refractive index layer (α), it is allowed to dry naturally or by forced drying. Then, the low refractive index layer (β) is obtained by curing by irradiation with active energy rays.

[0054] The means for forming the low refractive index layer are not particularly limited, but a wet coating method is preferred from the viewpoint of foldability. Examples of application methods for the wet coating method include, but are not limited to, bar coaters, spray coaters, spin coaters, dip coaters, die coaters, comma coaters, and gravure coaters.

[0055] For irradiation with active energy rays, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, gallium lamps, xenon lamps, carbon arc lamps, etc., can be used as light sources for ultraviolet light and visible light with wavelengths of 400-500 nm. For electron sources, thermionic radiation guns, electrolytic radiation guns, etc., can be used. The amount of active energy irradiated should be sufficient to obtain adequate curing, for example, 50-2000 mJ / cm².2 It can be considered to be of a certain degree. [Examples]

[0056] The present invention will be described in more detail below with reference to examples and comparative examples, but the following examples do not limit the technical scope of the present invention in any way. In the examples, "parts" means "parts by mass" and "%" means "percent mass". Furthermore, the amounts listed in the table are in parts by mass, and for ingredients other than the solvent, the values ​​are calculated based on non-volatile content. Blank spaces in the table indicate that an ingredient is not included.

[0057] <Preparation of composition for forming a hard coat layer> A composition for forming a hard coat layer was obtained by thoroughly mixing 100 parts of UV-1700B (manufactured by Mitsubishi Chemical Corporation) as an ultraviolet-curable resin and 5 parts of OMNIRAD 184 (manufactured by IGM-Resins BV) as a photopolymerization initiator, and then adding propylene glycol monomethyl ether as an organic solvent to adjust the non-volatile content to 40%.

[0058] <Preparation of composition for forming a low refractive index layer (X1)> Composition (X1) for forming a low refractive index layer was obtained by thoroughly mixing 66 parts of KAYARAD PET30 (manufactured by Nippon Kayaku Co., Ltd.) as an ultraviolet-curable resin, 1 part of NANOBYK3610 (manufactured by Big Chemie Japan, alumina sol) as inorganic oxide fine particles, 3 parts of KY-1203 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a fluorine-containing compound, 30 parts of Thruri-Ria 4320 (manufactured by JGC Catalysts & Chemicals Inc.) as hollow silica particles, and 3 parts of OMNIRAD 184 (manufactured by IGM-Resins BV) as a photopolymerization initiator, and then adding propylene glycol monomethyl ether as an organic solvent to adjust the non-volatile content to 6%.

[0059] Low refractive index layer-forming compositions (X2) to (X4) were obtained in the same manner as (X1), except that the materials and proportions listed in Table 1 were changed.

[0060] [Table 1]

[0061] [Example 1] <Preparation of an active energy ray curable composition (Y1) for forming a high refractive index layer> 31 parts of Violet UV-1700B (manufactured by Mitsubishi Chemical Corporation) as compound (A), 5 parts of MAC-SQ HDM (manufactured by Toagosei Co., Ltd.) as compound (B), 64 parts of Zircostar ZP-153 (manufactured by Nippon Shokubai Co., Ltd.) as metal oxide particles (C), and 5 parts of OMNIRAD 184 (manufactured by IGM-Resins BV) as a photopolymerization initiator (D) were thoroughly mixed, and propylene glycol monomethyl ether was added as an organic solvent to adjust the non-volatile content to 5% to obtain an active energy ray curable composition (Y1) for forming a high refractive index layer.

[0062] <Manufacturing of anti-reflective film> A hard coat layer-forming composition was applied to a 50 μm thick polyethylene terephthalate (PET) film (Toray Industries, Inc.'s "Lumirror U403") using a bar coater to achieve a dry film thickness of 4.0 μm. After drying in a drying oven at 100°C for 1 minute, it was subjected to a high-pressure mercury lamp treatment at 400 mJ / cm². 2 A hard coat layer was formed by irradiating with ultraviolet light. The high refractive index layer-forming composition (Y1) of Example 1 was applied to the hard coat layer using a bar coater so that the film thickness after drying was 100 nm, dried in a drying oven at 100°C for 2 minutes, and then treated with a high-pressure mercury lamp at 400 mJ / cm². 2 A high refractive index layer (α) was formed by irradiating with ultraviolet light. A low refractive index layer forming solution (X1) was applied to the high refractive index layer (α) using a bar coater so that the film thickness after drying was 100 nm. After drying in a drying oven at 100°C for 1 minute, it was heated with a high-pressure mercury lamp at 400 mJ / cm² under a nitrogen atmosphere with an oxygen concentration of 500 ppm or less. 2 By irradiating with ultraviolet light, a low refractive index layer (β) was formed, and the anti-reflective film of Example 18 was obtained.

[0063] [Examples 2-20, Comparative Examples 1-5] Except for the materials and proportions listed in Tables 2 and 3, the active energy ray curable compositions (Y2) to (Y17) of Examples 5 to 20 and the active energy ray curable compositions (Y'1) to (Y'5) of Comparative Examples 1 to 5 were obtained in the same manner as in Example 1. Furthermore, the anti-reflective films of Examples 2 to 20 and Comparative Examples 1 to 5 were obtained in the same manner as in Example 1.

[0064] The details of the abbreviations in Tables 2 and 3 are as follows: <Compound (A)> a1: Shiko UV-1700B (urethane acrylate, 10 functional groups, manufactured by Mitsubishi Chemical Corporation) a2: KAYARAD DPHA (Dipentaerythritol hexaacrylate, 6 functional groups, manufactured by Nippon Kayaku Co., Ltd.) <Compounds containing two (meth)acryloyl groups> Miramer M220 (TPGDA, 2 functional units, manufactured by MIWON) <Compound (B)> b1-1: MAC-SQ HDM (Propylene glycol monobutyl ether solution with a non-volatile content of 50%, manufactured by Toagosei Co., Ltd., containing methacryloyl groups) b1-2: AC-SQ SI20 (manufactured by Toagosei Co., Ltd., contains acryloyl group) b2: SR-13 (manufactured by Konishi Chemical Industry Co., Ltd., without (meth)acryloyl group) <Metal oxide particles (C)> c-1: Zircostar ZP-153 (Zirconia sol, MEK dispersion with 70 wt% zirconium oxide particle content, manufactured by Nippon Shokubai Co., Ltd.) c-2: NS405 (Titania sol: Propylene glycol monomethyl ether acetate dispersion with 30 wt% titanium dioxide particles, manufactured by Teika Co., Ltd.) c-3: NANOBYK 3610 (Propylene glycol monomethyl ether acetate dispersion with alumina sol and 30 wt% aluminum oxide particles, manufactured by Big Chemie Japan) <Inorganic oxide fine particles> Silica particles (refractive index 1.43): MEK-ST-40 (silica sol, methyl ethyl ketone dispersion with 40 wt% particle content, manufactured by Nissan Chemical Corporation) <Photopolymerization initiator (D)> d1: Omnirad 184 (acetophenone-based photopolymerization initiator, manufactured by IGM-Resins BV) <Other ingredients (E)> Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resonaq)

[0065] <Refractive index> A 50 μm thick polyethylene terephthalate (PET) film (Toray Industries, Inc.'s "Lumirror U403") is coated with a low refractive index layer formation composition and a high refractive index layer formation composition using a bar coater, respectively, so that the film thickness after drying is 1 μm. Then, it is cured with a high-pressure mercury lamp at 400 mJ / cm². 2 A coated material for refractive index measurement was fabricated by irradiating it with ultraviolet light. The refractive index at a wavelength of 594 nm was measured for the high refractive index layer and the low refractive index layer using the "Prism Coupler Model 2010" manufactured by Metricon.

[0066] <HZ[%]; Haze value> The haze value (Hz) of the anti-reflective film was measured using the "Haze Meter SH7000" manufactured by Nippon Denshoku Industries Co., Ltd. A value of 1.0% or less is considered acceptable for practical use.

[0067] <5°reflectance> Measurements were taken in accordance with JIS Z8722 using a Hitachi High-Tech Science Co., Ltd. "Spectrophotometer U4100" and "5° Specular Reflectance Applicator." Test specimens were prepared by sanding the back surface (the side opposite the low refractive index layer) of the fabricated anti-reflective film with sandpaper, and then applying black ink. The lowest reflectance value in the 380-780 nm range was then determined as the minimum reflectance. A value of 2.0% or less is considered acceptable for practical use.

[0068] <Stability over time> The high refractive index layer-forming composition was prepared and left to stand at room temperature. The presence or absence of precipitate was visually checked every 10 days and evaluated according to the following criteria. ○ and △ indicate levels that are practically acceptable. [Evaluation Criteria] • ○: No precipitate was found after 10, 20, or 30 days from the preparation date. •△: No precipitate after 10 days from preparation, but a deposit was present after 20 days from preparation. • ×: Sediment present 10 days after preparation.

[0069] <Abrasion resistance; SW resistance> Scratch resistance was evaluated using the "JSPS-type friction fastness tester" manufactured by Tester Sangyo Co., Ltd. A friction element with a load of 1000g attached (surface area 4cm²) was used. 2 Steel wool #0000 was attached to the surface of the anti-reflective film and passed back and forth 1000 times. Afterwards, the number of scratches on the surface was counted and evaluated according to the following criteria. ◎, ○, and △ represent levels that are not problematic in practical use. [Evaluation Criteria] • ◎: No scratches • ○: 1 to less than 5 scratches • △: 5 to 10 scratches ×: More than 10 scratches

[0070] [Table 2]

[0071] [Table 3]

[0072] As shown in Tables 1-3, the high refractive index layer-forming composition of the present invention exhibits excellent long-term stability. Furthermore, it was confirmed that the anti-reflective film obtained using this composition exhibits excellent adhesion between the high refractive index layer and the low refractive index layer, and high scratch resistance. Comparative Examples 1 and 5, which do not contain compound (B) in the high refractive index layer-forming composition, showed poor scratch resistance evaluation results due to insufficient adhesion between the high refractive index layer and the low refractive index layer. Comparative Examples 2 and 3, which do not contain metal oxide particles (C) or use metal oxide particles with a low refractive index, could not obtain a reflectivity that is practical for use as an anti-reflective film. Comparative Example 4 has two functional groups of compound (A), resulting in poor scratch resistance evaluation results due to insufficient hardness. In particular, Comparative Example 5, which uses an acrylate monomer having an isocyanate group to improve adhesion with the low refractive index layer, shows poor long-term stability of the high refractive index layer-forming composition. [Explanation of symbols]

[0073] The symbols in Figures 1 and 2 are explained below. 1. Anti-reflective film 2 Light-transparent base material 3. High refractive index layer 4. Low refractive index layer 5. Hard court layer

Claims

1. It has a laminated structure in which a light-transmitting substrate, a high refractive index layer (α), and a low refractive index layer (β) are arranged in this order. The high refractive index layer (α) is a cured product of an active energy ray curable composition. The anti-reflective film is characterized in that the active energy ray curable composition comprises a compound (A) having three or more (meth)acryloyl groups, a compound (B) having a silsesquioxane skeleton, metal oxide particles (C) having a refractive index of 1.70 to 2.72, and a photopolymerization initiator (D). (However, compound (A) is excluding compound (B).)

2. The anti-reflective film according to claim 1, characterized in that the metal oxide particles (C) include one or more selected from the group consisting of zirconium oxide particles, titanium oxide particles, and aluminum oxide particles.

3. The anti-reflective film according to claim 1, characterized in that the low refractive index layer (β) contains hollow particles.

4. The anti-reflective film according to claim 3, characterized in that the low refractive index layer (β) further comprises inorganic oxide fine particles (excluding hollow particles).

5. The anti-reflective film according to claim 1, characterized in that the compound (B) having a silsesquioxane skeleton comprises a compound (b1) having a silsesquioxane skeleton and a (meth)acryloyl group.

6. The anti-reflective film according to claim 1, characterized in that the compound (A) contains a compound (a1) having eight or more (meth)acryloyl groups.

7. The anti-reflective film according to claim 1, characterized in that the minimum value of the reflectance measured at an incident angle of 5° in the wavelength range of 380 to 780 nm is 2% or less.

8. An active energy ray curable composition for forming a high refractive index layer (α) in an anti-reflective film according to any one of claims 1 to 7.

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