Antireflection film and active energy ray-curable composition

Abstract

This antireflection film has a layered 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 active energy ray-curable composition contains: 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 1.70-2.72; and a photopolymerization initiator (D). (However, the compound (A) excludes the compound (B)).

Description

Anti-reflective film and active energy ray curable composition

[0001] This disclosure relates to an active energy ray curable composition and an active energy ray curable composition.

[0002] Image display devices such as liquid crystal displays, organic EL displays, and touch panels in smartphones are equipped with anti-glare films or anti-reflective films on their image display surfaces to suppress reflections of ambient light.

[0003] Anti-reflective films reduce reflectivity through the interference effect of light, where light reflected from the surface of a low refractive index layer and light reflected from the interface between the low refractive index layer and an adjacent layer (such as a hard coat layer or a high refractive index layer).

[0004] Anti-reflective films are often laminated on the outermost layer of a display, and therefore require scratch resistance and abrasion resistance.

[0005] Methods for achieving high scratch resistance include increasing film hardness, creating surface irregularities, and improving adhesion between layers.

[0006] Patent Document 1 describes an anti-reflective film having a hard coat layer on the surface of a transparent substrate film, and further having a high refractive index layer and a low refractive index layer on the hard coat layer in that order. In this film, scratch resistance is improved by using a specific monomer having an isocyanate group in the composition for forming the high refractive index layer to enhance the adhesion between the high refractive index layer and the low refractive index layer.

[0007] Japanese Patent Publication No. 2008-207477

[0008] The anti-reflective film disclosed in Patent Document 1 has insufficient scratch resistance, and higher scratch resistance is required. Furthermore, in the composition of the high refractive index layer-forming composition disclosed in Patent Document 1, if a large amount of monomers having isocyanate groups are incorporated, the high refractive index particles tend to aggregate and settle, posing a problem for the long-term stability of the composition.

[0009] Some embodiments of this disclosure are anti-reflective films 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, and aim to provide anti-reflective films having superior scratch resistance compared to conventional films, and active energy ray curable compositions with excellent temporal stability for obtaining said anti-reflective films.

[0010] The inventors have conducted extensive research to solve the above problems and have arrived at the following invention. This disclosure provides the following anti-reflective film and active energy ray curable composition.

[0011] <1>: An antireflective 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) having a refractive index of 1.70 to 2.72, and a photopolymerization initiator (D). (However, compound (A) excludes compound (B).) <2>: The antireflective film according to <1>, wherein the metal oxide particles (C) include at least one selected from the group consisting of zirconium oxide particles, titanium oxide particles, and aluminum oxide particles. <3>: The antireflective film according to <1> or <2>, wherein the low refractive index layer (β) includes hollow particles. <4>: The anti-reflective film according to any one of <1> to <3>, wherein the low refractive index layer (β) contains inorganic oxide fine particles (excluding hollow particles). <5>: The anti-reflective film according to any one of <1> to <4>, wherein the compound (B) having a silsesquioxane skeleton contains a compound (b1) having a silsesquioxane skeleton and (meth)acryloyl groups. <6>: The anti-reflective film according to any one of <1> to <5>, wherein the compound (A) contains a compound (a1) having eight or more (meth)acryloyl groups. <7>: The anti-reflective film according to any one of <1> to <6>, wherein 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>: The anti-reflective film according to any one of <1> to <7>, wherein the content of the compound (B) having a silsesquioxane skeleton is 0.1 to 60% by mass in 100% by mass of the non-volatile content of the active energy ray curable composition. <9>: The anti-reflective film according to any one of <1> to <7>, wherein the content of metal oxide particles (C) is 5 to 90% by mass of 100% by mass of the non-volatile content of the active energy ray curable composition.<10>: The anti-reflective film according to any one of <1> to <7>, wherein the content of compound (B) having a silsesquioxane skeleton is 0.1 to 60% by mass of 100% by mass of the non-volatile content of the active energy ray curable composition, and the content of metal oxide particles (C) is 5 to 90% by mass of 100% by mass of the non-volatile content of the active energy ray curable composition. <11>: The anti-reflective film according to <10>, wherein the content of compound (B) having a silsesquioxane skeleton is 0.1 to 9.5% by mass of 100% by mass of the non-volatile content of the active energy ray curable composition. <12>: An active energy ray curable composition for forming a high refractive index layer (α) in the anti-reflective film according to any one of <1> to <11>.

[0012] Several embodiments of this disclosure make it possible to provide an anti-reflective film with excellent scratch resistance, and an active energy ray curable composition with excellent temporal stability for obtaining the anti-reflective film.

[0013] This is a schematic cross-sectional view partially showing an anti-reflective film (without a hard coat layer) according to one embodiment of the present disclosure. This is a schematic cross-sectional view partially showing an anti-reflective film (with a hard coat layer) according to one embodiment of the present disclosure.

[0014] Several embodiments of this disclosure will be described in detail below. In this specification, when "(meth)acryloyl" is used, it refers to "acryloyl or methacryloyl" unless otherwise specified. Furthermore, "compound (A) having three or more (meth)acryloyl groups" may be referred to as "compound (A)", "compound (a1) having eight or more (meth)acryloyl groups" as "compound (a1)", "compound (B) having a silsesquioxane skeleton" as "compound (B)", "compound (b1) having a silsesquioxane skeleton and (meth)acryloyl groups" as "compound (b1)", and "metal oxide particles (C) with a refractive index of 1.70 to 2.72" as "metal oxide particles (C)". Unless otherwise noted, each main component mentioned herein may be used independently, alone, or in combination of two or more.

[0015] In this specification, any numerical range specified using "~" includes the numbers before and after "~" as the lower and upper limits.

[0016] [Anti-reflective film] In some embodiments of the present disclosure, the anti-reflective film is a laminate comprising a light-transmitting substrate, a high refractive index layer (α), and a low refractive index layer (β) arranged in that order. The anti-reflective film may further have other cured film layers, such as a hard coat layer or an optical adjustment layer, between the light-transmitting substrate, the high refractive index layer (α), and the low refractive index layer (β).

[0017] From the viewpoint of anti-reflective properties, the anti-reflective film preferably has a minimum reflectance of 2% or less at a wavelength of 380 to 780 nm, measured at an incident angle of 5°. It is more preferably 1.5% or less, and particularly preferably 1.0% or less. For example, this reflectance may be 0.1 to 2, 0.2 to 1.9, 0.3 to 1.8, or 0.4 to 1.7, and may be 0.1 to 1.5, 0.1 to 1.0, 0.1 to 0.9, or 0.1 to 0.5.

[0018] The film thicknesses of the high refractive index layer (α) and the low refractive index layer (β) are preferably 50 to 150 nm, more preferably 70 to 140 nm, respectively, in order to obtain good reflectivity from the optical interference effect with other interfaces. For example, they may be 80 to 120 nm, 90 to 110 nm, or 95 to 100 nm. The film thicknesses of the high refractive index layer (α) and the low refractive index layer (β) may be the same or different. The film thicknesses of the high refractive index layer (α) and the low refractive index layer (β) can be determined by observing the cross-section of the anti-reflective film and taking the arithmetic mean of the film thickness at five measurement points. Alternatively, the film thicknesses of the high refractive index layer (α) and the low refractive index layer (β) can also be determined by calculating the film thickness after drying from the amount of coating of the composition. It is desirable that either of these two measurement methods satisfies the above range of film thickness.

[0019] <<Light-Transmitting Substrates>> Light-transmitting substrates are not particularly limited as long as they have light-transmitting properties, and examples include glass, synthetic resin molded products, and films. The thickness of the substrate is not particularly limited, but is usually around 25 to 200 μm.

[0020] Examples of molded synthetic resin products include polymethyl methacrylate resin, copolymer resins mainly composed of methyl methacrylate, polystyrene resin, styrene-methyl methacrylate copolymer resin, styrene-acrylonitrile copolymer resin, polycarbonate resin, cellulose acetate butyrate resin, polyaryl diglycol carbonate resin, polyvinyl chloride resin, and polyester resin.

[0021] Examples of films include polyester film, polyethylene film, polypropylene film, cellophane film, diacetylcellulose film, triacetylcellulose (TAC) film, acetylcellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, polyolefin film, polystyrene film, polycarbonate film, polymethylpentel film, polysulfone film, polyetheretherketone film, polyethersulfone film, polyetherimide film, polyimide film, fluororesin film, nylon film, and acrylic film.

[0022] ≪High refractive index layer (α)≫ In some embodiments of the present disclosure, the antireflective film comprises a high refractive index layer (α), which is a cured product of an active energy ray curable composition.

[0023] 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 reflectivity, 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. For example, the refractive index of this high refractive index layer (α) may be 1.52 to 1.90, 1.52 to 1.90, or 1.55 to 1.90, and may also be 1.6 to 1.90, 1.65 to 1.88, 1.70 to 1.85, or 1.5 to 1.80.

[0024] <Active Energy Ray Curable Composition> 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). 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.

[0025] (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.

[0026] 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 types.

[0027] Compound (A) is broadly classified into compound (a1) having eight or more (meth)acryloyl groups and compound (a2) having three to seven (meth)acryloyl groups, and 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.

[0028] 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 three to seven (meth)acryloyl groups include, but are not limited to, MIRAMER M300, MIRAMER M500, MIRAMER M600, MIRAMER PU610 manufactured by MIWON Corporation, and KAYARAD DPHA and KAYARAD PET30 manufactured by Nippon Kayaku Co., Ltd.

[0029] 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). For example, the content of compound (A) may be 1 to 98% by mass, 5 to 95% by mass, 10 to 90% by mass, or 20 to 80% by mass, and may be 25 to 55% by mass, 27 to 50% by mass, 30 to 45% by mass, or 31 to 40% by mass.

[0030] (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 is less likely to occur even when added in large quantities to improve adhesion to the low refractive index layer, thus achieving both the long-term stability and adhesion of the composition.

[0031] Compound (B) is obtained by hydrolysis and condensation of silsesquioxane, i.e., a trifunctional silane (RSiO １．５ ) The compound is not particularly limited as long as it has a network polymer or polyhedral cluster structure having an n structure, and 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. (RSio １．５ ) where n is an integer greater than or equal to 2. Preferably, n is an integer between 2 and 200, more preferably between 2 and 150, and even more preferably between 2 and 100. Also, (RSio １．５ In n, R is preferably an organic group such as a methyl group, an ethyl group, a phenyl group, or a (meth)acryloyl group.

[0032] Compound (B) is (RSio １．５ It is preferable that the compound (b1) contains a silsesquioxane skeleton and a compound (b1) having a (meth)acryloyl group, wherein at least a portion of R is a (meth)acryloyl group. The adhesion to the low refractive index layer is improved by the action of the (meth)acryloyl group of compound (b1). Note that if the compound has a silsesquioxane skeleton, it is classified as compound (B) even if it has three or more (meth)acryloyl groups.

[0033] 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. 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, manufactured by Konishi Chemical Industry Co., Ltd., SQ107, SQ109, and SQ506, manufactured by Arakawa Chemical Industries, Ltd., and OX-SQ TX-100, OX-SQ SI-20, and OX-SQH DX, all manufactured by Toagosei Co., Ltd.

[0034] 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 is 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. For example, the content of compound (B) having a silsesquioxane skeleton may be 0.1 to 80% by mass, 0.1 to 70% by mass, 0.1 to 60% by mass, 0.5 to 60% by mass, 1 to 60% by mass, or 3 to 50% by mass, and may be 5 to 50% by mass, 5 to 40% by mass, 5 to 30% by mass, 5 to 20% by mass, 5 to 10% by mass, or 5 to 9.5% by mass.

[0035] (Metal oxide particles (C)) 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. For example, the refractive index of metal oxide particles (C) may be 1.70 to 2.72, 1.75 to 2.72, 1.76 to 2.71, or 2.17 to 2.71.

[0036] 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 at least one 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.

[0037] 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.

[0038] The content fraction of the 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 in 100% by mass of the non-volatile content of the active energy ray-curable composition for forming the high refractive index layer (α) from the viewpoint of achieving both high refractive index and scratch resistance. For example, the content fraction of the metal oxide particles (C) may be 0.1 to 80% by mass, 0.5 to 75% by mass, or 1 to 70% by mass, and may be 5 to 70% by mass, 10 to 65% by mass, 15 to 65% by mass, 20 to 65% by mass, 30 to 65% by mass, 40 to 65% by mass, or 50 to 65% by mass.

[0039] (Photoinitiator (D)) As the photoinitiator (D), for example, monocarbonyl-based photoinitiators, dicarbonyl-based photoinitiators, acetophenone-based photoinitiators, benzoin ether-based photoinitiators, acylphosphine oxide-based photoinitiators, aminocarbonyl-based photoinitiators, etc. can be used. The photoinitiator (D) may be used in combination with a sensitizer.

[0040] 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;Also, aminocarbonyl-based photoinitiators such as ethyl-4-(dimethylamino)benzoate, 2-n-butoxyethyl-4-(dimethylamino)benzoate, isoamyl-4-(dimethylamino)benzoate, 2-(dimethylamino)ethyl benzoate, 4,4'-bis-4-dimethylaminobenzophenone, 4,4'-bis-4-diethylaminobenzophenone, and 2,5'-bis(4-diethylaminobenzal)cyclopentanone can be mentioned. ;

[0041] As commercially available products of the photoinitiator (D), Omnirad 184, 651, 500, 907, 127, 369, 784, 2959, Esacure One manufactured by IGM-Resins B.V., Lucirin TPO manufactured by BASF, etc. can be mentioned. In particular, from the viewpoint of yellowing resistance after curing with active energy rays, Omnirad 184 is preferable.

[0042] The content of the photoinitiator (D) is not limited as long as it contains an amount that allows the active energy ray-curable composition to be cured to have predetermined physical properties by ultraviolet rays. However, from the viewpoints of curing rate, hardness, and scratch resistance, it is preferably 1 to 15% by mass, more preferably 3 to 10% by mass, and even more preferably 5 to 8% by mass in 100% by mass of the non-volatile content of the active energy ray-curable composition.

[0043] In some embodiments, with respect to 100 parts by mass of the compound (A), the compound (B) may be 5 to 250 parts by mass, 5 to 100 parts by mass, 5 to 50 parts by mass, may be 10 to 50 parts by mass, 12 to 40 parts by mass, or 15 to 30 parts by mass. In some embodiments, with respect to 100 parts by mass of the compound (A), the metal oxide particles (C) may be 1 to 300 parts by mass, 30 to 300 parts by mass, or 60 to 300 parts by mass, may be 60 to 280 parts by mass, 100 to 260 parts by mass, 150 to 230 parts by mass, or 180 to 220 parts by mass. In some embodiments, with respect to 100 parts by mass in total of the compound (A) and the compound (B), the photoinitiator (D) may be 1 to 20 parts by mass, 5 to 18 parts by mass, or 10 to 15 parts by mass.

[0044] (Solvent) In some embodiments, the active energy ray curable composition may contain a solvent as needed. When a solvent is added, it is preferable to perform the curing treatment with active energy rays after the solvent has evaporated. When a solvent is added, for example, the solvent content may be 1 to 80% by mass, 3 to 60% by mass, or 5 to 50% by mass of 100% by mass of the active energy ray curable composition. In some embodiments, the active energy ray curable composition may be solvent-free. In the case of a solvent-free active energy ray curable composition, the solvent content may be 1% by mass or less, 0.5% by mass or less, or 0.1% by mass or less of 100% by mass of the non-volatile content of the active energy ray curable composition, and it is preferable that the active energy ray curable composition is substantially free of solvent.

[0045] 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.

[0046] (Other components (E)) In addition, other components not listed above may be included to the extent that they do not impair the purpose or effect of this disclosure. 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, ultraviolet absorbers, plasticizers, preservatives, dispersants, defoamers, silane coupling agents, inorganic fillers, etc.

[0047] ≪Low Refractive Index Layer (β)≫ The low refractive index layer (β) is formed using a composition for forming a 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 preferable to further contain inorganic oxide fine particles (except for hollow particles).

[0048] <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).

[0049] 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.

[0050] Examples of commercially available hollow particles include JGC Catalysts & Chemicals' Thru-Ria 4320 and Sekisui Chemicals' Techpolymer XX5964Z.

[0051] Inorganic oxide fine particles form protrusions on the surface of the low refractive index layer, and these protrusions provide good scratch resistance. Examples of inorganic oxide fine particles include aluminum oxide and silica. Even if inorganic oxide fine particles are hollow, they are classified as hollow particles. The inorganic oxide fine particles are not particularly limited as long as they are of a particle size commonly used in compositions for forming low refractive index layers.

[0052] Examples of commercially available inorganic oxide nanoparticles include NANOBY K3610 from Big Chem Japan and Rio Duras KT-110AL from Toyo Chem Co., Ltd.

[0053] The content of 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.

[0054] 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.

[0055] 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. For example, at a refractive index of 594 nm, the difference between the refractive index of the high refractive index layer (α) and the refractive index of the low refractive index layer (β) may be 0.05 to 0.35, 0.07 to 0.35, or 0.1 to 0.3, and may also be 0.15 to 0.3, 0.2 to 0.3, or 0.25 to 0.3.

[0056] ≪Method for Manufacturing Anti-Reflective Film≫ In some embodiments of this disclosure, an anti-reflective film can be formed by the following methods, but is not limited thereto. For example, various coating methods such as using a lot, wire bar, microgravure, gravure, die, curtain, lip, slot, or spin can be used. After forming a coating film of a composition for forming a 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 a composition for forming a low refractive index layer (β), 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.

[0057] 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.

[0058] 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.

[0059] Hereinafter, several embodiments of anti-reflective films of the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the specific examples shown in the drawings. Figure 1 is a schematic cross-sectional view partially showing one embodiment of anti-reflective film 1 (without a hard coat layer). The anti-reflective film 1 shown in Figure 1 has a laminated structure in which a light-transmitting substrate 2, a high refractive index layer 3, and a low refractive index layer 4 are arranged in this order. Figure 2 is a schematic cross-sectional view partially showing one embodiment of anti-reflective film 1 (with a hard coat layer). The anti-reflective film 1 shown in Figure 2 has a laminated structure in which a light-transmitting substrate 2, a high refractive index layer 3, and a low refractive index layer 4 are arranged in this order, and further has a hard coat layer between the light-transmitting substrate 2 and the high refractive index layer 3. The hard coat layer may be provided between the high refractive index layer 3 and the low refractive index layer 4. Although not shown, the anti-reflective film may further have an optical adjustment layer. The optical adjustment layer may be provided between the light-transmitting substrate 2 and the high refractive index layer 3, between the high refractive index layer 3 and the low refractive index layer 4, or both. The hard coat layer and the optical adjustment layer are not particularly limited as long as they are known materials that have been used in anti-reflective films and the like in the past, but from the standpoint of productivity, they are preferably cured products of active energy ray curable compositions.

[0060] <Active Energy Ray Curable Compositions> Several embodiments can provide active energy ray curable compositions for forming a high refractive index layer (α) in the anti-reflective film of the embodiments described above. As described above, the active energy ray curable composition for forming the high refractive index layer (α) may include 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).

[0061] The present disclosure will be further described below with reference to examples and comparative examples, but the following examples do not limit the technical scope of the present disclosure in any way. In the examples, "parts" means "parts by mass" and "%" means "mass percent". Also, the blending amounts in the table are in parts by mass, and all except the solvent are calculated on a non-volatile content basis. Blank spaces in the table indicate that the substance was not blended.

[0062] <Preparation of composition for hard coat layer formation> 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 B.V.) as a photopolymerization initiator were thoroughly mixed, and propylene glycol monomethyl ether was added as an organic solvent to prepare the mixture to have a non-volatile content of 40% to obtain a composition for hard coat layer formation.

[0063] <Preparation of composition for forming a low refractive index layer (X1)> 66 parts of KAYARAD PET30 (manufactured by Nippon Kayaku Co., Ltd.) as an ultraviolet-curable resin, 1 part of NANOBY K3610 (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 Co., Ltd.) as hollow silica particles, and 3 parts of OMNIRAD 184 (manufactured by IGM-Resins B.V.) as a photopolymerization initiator were thoroughly mixed, and propylene glycol monomethyl ether was added as an organic solvent to adjust the non-volatile content to 6% to obtain composition for forming a low refractive index layer (X1).

[0064] 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.

[0065]

[0066] [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 B.V.) 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.

[0067] <Preparation of Anti-Reflective Film> A hard coat layer-forming composition is applied to a 50 μm thick polyethylene terephthalate (PET) film (Toray Industries, Inc.'s "Lumirror U403") using a bar coater to achieve a film thickness of 4.0 μm after drying. After drying in a drying oven at 100°C for 1 minute, it is heated with a high-pressure mercury lamp 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 heated 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.

[0068] [Examples 2-20, Comparative Examples 1-5] Active energy ray curable compositions (Y2)-(Y17) of Examples 5-20 and active energy ray curable compositions (Y'1)-(Y'5) of Comparative Examples 1-5 were obtained in the same manner as (Y1), except that the materials and amounts of the formulations were changed as described in Tables 2 and 3. Furthermore, anti-reflective films of Examples 2-20 and Comparative Examples 1-5 were obtained in the same manner as in Example 1.

[0069] The details of the abbreviations in Tables 2 and 3 are as follows. 〈Compound (A)〉 a1: Violet light UV-1700B (urethane acrylate, number of functional groups 10, manufactured by Mitsubishi Chemical Corporation) a2: KAYARAD DPHDA (dipentaerythritol hexaacrylate, number of functional groups 6, manufactured by Nippon Kayaku Co., Ltd.) 〈Compound having two (meth)acryloyl groups〉 Miramer M220 (TPGDA, number of functional groups 2, manufactured by MIWON) 〈Compound (B)〉 b1-1: MAC-SQ HDM (propylene glycol monobutyl ether solution with a non-volatile content concentration of 50%, manufactured by Toagosei Co., Ltd., containing a methacryloyl group) b1-2: AC-SQ SI20 (manufactured by Toagosei Co., Ltd., containing an 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 containing 70 wt% zirconium oxide particles, manufactured by Nippon Shokubai Co., Ltd.) c-2: NS405 (titania sol: propylene glycol monomethyl ether acetate dispersion containing 30 wt% titanium oxide particles, manufactured by Teika Co., Ltd.) c-3: NANOBYK 3610 (alumina sol, propylene glycol monomethyl ether acetate dispersion containing 30 wt% aluminum oxide particles, manufactured by Big Chemie Japan Co., Ltd.) 〈Inorganic oxide fine particles〉 Silica particles (refractive index 1.43): MEK-ST-40 (silica sol, methyl ethyl ketone dispersion containing 40 wt% particles, manufactured by Nissan Chemical Industries, Ltd.) 〈Photopolymerization initiator (D)〉 d1: Omnirad 184 (acetophenone-based photopolymerization initiator, manufactured by IGM-Resins B.V.) 〈Other components (E)〉 Carenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resona Co., Ltd.)

[0070] 〈Refractive index〉 On a 50 μm-thick polyethylene terephthalate (PET) film (Lumirror U403 manufactured by Toray Industries, Inc.), a low refractive index layer-forming composition and an active energy ray-curable composition for forming a high refractive index layer were each coated using a bar coater so that the film thickness after drying would be 1 μm, and then irradiated with a high-pressure mercury lamp at 400 mJ / cm 2A coated material for refractive index measurement was fabricated by irradiating it with ultraviolet light. The refractive index of the high refractive index layer and the low refractive index layer at a wavelength of 594 nm was measured using the "Prism Coupler Model 2010" manufactured by Metricon.

[0071] <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 acceptable for practical use.

[0072] <5° Reflectance> Measurements were taken in accordance with JIS Z8722 using a Hitachi High-Tech Science Co., Ltd. "Spectrophotometer U4100" and "5° Specular Reflectance Apparatus". After sanding the back surface (the side opposite the low refractive index layer) of the fabricated anti-reflective film with sandpaper, black ink was applied to create a test specimen. Subsequently, the lowest reflectance value in the 380-780 nm range was determined as the minimum reflectance. A value of 2.0% or less is considered to be at a level that does not pose a practical problem.

[0073] <Stability over time> After preparing the high refractive index layer-forming composition, it was 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. Note that ○ and △ are levels that do not pose practical problems. [Evaluation criteria] ・○: No precipitate at 10, 20, and 30 days from preparation ・△: No precipitate at 10 days from preparation, but precipitate was present at 20 days from preparation ・×: Precipitate was present at 10 days from preparation

[0074] <Scratch 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 a sieve and the surface of the anti-reflective film was run back and forth 1000 times. After that, the number of scratches on the surface was counted and evaluated according to the following criteria. ◎, ○, and △ are levels that are not problematic in practical use. [Evaluation Criteria] ・◎: No scratches ・○: 1 to less than 5 scratches ・△: 5 to less than 10 scratches ・×: 10 or more scratches

[0075]

[0076]

[0077] As shown in Tables 1 to 3, the high-refractive-index layer-forming compositions of each example exhibit excellent long-term stability. Furthermore, it was confirmed that the anti-reflective films obtained using these compositions exhibit 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, also showed poor scratch resistance evaluation results and failed to obtain a reflectivity that is practical for use as an anti-reflective film. Comparative Example 4 shows poor scratch resistance evaluation results due to insufficient hardness because compound (A) has two functional groups. 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.

[0078] Although the present invention has been described with reference to several embodiments described above, the present invention is not limited to these embodiments. Various modifications can be made to the structure and details of the present invention within the scope of the invention. This disclosure is related to the subject matter described in Japanese Patent Application No. 2024-225510, filed on December 20, 2024, all of which are incorporated herein by reference.

[0079] 1. Anti-reflective film, 2. Light-transmitting substrate, 3. High refractive index layer, 4. Low refractive index layer, 5. Hard coat layer

Claims

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) having 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 according to claim 1, wherein the metal oxide particles (C) include at least one 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, wherein the low refractive index layer (β) includes hollow particles.

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

5. The anti-reflective film according to claim 1, wherein 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, wherein the compound (A) comprises a compound (a1) having eight or more (meth)acryloyl groups.

7. The anti-reflective film according to claim 1, wherein 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. The anti-reflective film according to claim 1, wherein the content of compound (B) having a silsesquioxane skeleton is 0.1 to 60% by mass of 100% by mass of the non-volatile content of the active energy ray curable composition.

9. The anti-reflective film according to claim 1, wherein the content of metal oxide particles (C) is 5 to 90% by mass of 100% by mass of the non-volatile content of the active energy ray curable composition.

10. The anti-reflective film according to claim 1, wherein the content of compound (B) having a silsesquioxane skeleton is 0.1 to 60% by mass of 100% by mass of the non-volatile content of the active energy ray curable composition, and the content of metal oxide particles (C) is 5 to 90% by mass of 100% by mass of the non-volatile content of the active energy ray curable composition.

11. The anti-reflective film according to claim 10, wherein the content of compound (B) having a silsesquioxane skeleton is 0.1 to 9.5% by mass of 100% by mass of the non-volatile content of the active energy ray curable composition.

12. 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 11.

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