Low-reflection hard coating film and image display device including same

Abstract

The present invention relates to a low-reflection hard coating film in which a hard coating layer and a low-reflection layer are laminated in this order on a substrate layer, in which the optical film thickness of the low-reflection layer is represented by formula 1, the optical film thickness is from 0.670 lambda to 0.825 lambda with respect to a design wavelength (lambda), and the water contact angle of the low-reflection layer is 100 DEG or more, and an image display device comprising the same.

Description

Technical Field

[0001] The present invention relates to a low-reflection hard coating and an image display device comprising the same. Background Technology

[0002] With the rapid development of display technology, in image display devices such as LCD, CRT, PDP or OLED, a low-reflection film is usually placed on the visible side of the display device to prevent the contrast from decreasing due to the reflection of external light and the reflection of the image.

[0003] However, conventional low-reflection films are not resistant enough to external impacts or scratches. Therefore, they are usually not mounted on the outside of the display device, but rather consist of a separate functional layer to compensate for mechanical properties, or are used in combination with other components.

[0004] However, when low-reflection films contain a separate functional layer or are used in combination with other components, there are problems such as increased manufacturing costs due to complex manufacturing processes, and also disadvantages in achieving device thinning.

[0005] Therefore, there is a growing need for a low-reflection film that exhibits low reflectivity without requiring a separate functional layer to improve mechanical properties. Summary of the Invention

[0006] Technical issues

[0007] One object of the present invention is to provide a low-reflection hard coating film with low reflectivity and excellent anti-fouling properties.

[0008] In addition, another object of the present invention is to provide a low-reflection hard coating with excellent wear resistance and scratch resistance.

[0009] Furthermore, another object of the present invention is to provide an image display device comprising the aforementioned low-reflection hard coating.

[0010] Technical solution

[0011] This invention relates to a low-reflection hard coating film, wherein a hard coating layer and a low-reflection layer are sequentially stacked on a substrate layer, wherein the optical film thickness of the low-reflection layer is expressed by Formula 1, and is between 0.670λ and 0.825λ relative to a design wavelength (λ), and the water contact angle of the low-reflection layer is greater than 100°.

[0012] [Formula 1]

[0013] The thickness of the low-reflectivity optical film = n × d

[0014] (In equation 1 above,

[0015] n is the refractive index of the low-reflectivity layer, ranging from 1.38 to 1.50;

[0016] d represents the physical film thickness of the low-reflectivity layer.

[0017] According to a first aspect of the invention, the design wavelength (λ) can be from 380 to 780 nm.

[0018] According to a second aspect of the invention, the design wavelength (λ) can be 550 nm.

[0019] According to a third aspect of the invention, the water contact angle after the surface of the low-reflection layer undergoes 3,000 cycles of rubber abrasion test under a 500g load can be greater than 100°.

[0020] According to a fourth aspect of the invention, no scratches are produced when the surface of the low-reflection layer is subjected to 30 steel wool resistance tests under a load of 250 g / cm².

[0021] According to a fifth aspect of the invention, a separate functional layer may not be included on the low-reflectivity layer.

[0022] According to a sixth aspect of the present invention, the low-reflection layer may comprise a cured composition for forming a low-reflection layer, the composition for forming a low-reflection layer containing a fluorine-containing UV-curable functional compound, a light-transmitting resin, and inorganic nanoparticles.

[0023] According to a seventh aspect of the present invention, the inorganic nanoparticles may include any one of hollow inorganic nanoparticles and solid inorganic nanoparticles.

[0024] According to an eighth aspect of the present invention, the average particle size of the hollow inorganic nanoparticles may be 1 to 200 nm, and the average particle size of the solid inorganic nanoparticles may be 0.1 to 100 nm.

[0025] According to a ninth aspect of the present invention, the refractive index of the hollow inorganic nanoparticles may be from 1.17 to 1.40.

[0026] According to a tenth aspect of the invention, the composition for forming the low-reflection layer may contain, relative to the total weight of: 0.01 to 10% by weight of a fluorine-containing UV-curable functional compound; 1 to 80% by weight of a light-transmitting resin; and 0.1 to 35% by weight of inorganic nanoparticles.

[0027] According to the eleventh aspect of the present invention, the light transmittance of the low-reflection hard coating film can be above 90%, and the reflectance can be below 3.5%.

[0028] According to a twelfth aspect of the invention, the haze of the low-reflection hard coating film can be less than 1%.

[0029] Furthermore, the present invention relates to an image display device comprising the aforementioned low-reflection hard coating.

[0030] According to a thirteenth aspect of the invention, the low-reflection hard coating can be used as a front cover film for the image display device.

[0031] Invention Effects

[0032] The low-reflection hard coating of this invention not only possesses excellent low-reflection characteristics, but also eliminates the need for a separate functional layer to improve the mechanical properties or functionality of the low-reflection layer. It exhibits excellent anti-fouling, abrasion resistance, and scratch resistance, thus it can be used as a front cover film for image display devices. Therefore, the process of fabricating a separate functional layer can be omitted, improving process economy. Furthermore, the film is thinner than conventional films, offering advantages in achieving thinner image display devices and improving bending characteristics. Attached Figure Description

[0033] Figure 1 This is a diagram illustrating the laminated structure of a low-reflection hard coating film according to an embodiment of the present invention.

[0034] exist Figure 1 The symbols are shown below.

[0035] 10: Substrate layer

[0036] 20: Hard coating

[0037] 30: Low-reflectivity layer Detailed Implementation

[0038] This invention relates to a low-reflection hard coating and an image display device comprising the same. The low-reflection hard coating, through the design of the optical film thickness of the low-reflection layer, not only has excellent low-reflection characteristics, but also excellent anti-fouling, wear resistance and scratch resistance.

[0039] More specifically, the present invention relates to a low-reflection hard coating film and an image display device comprising the same, wherein the low-reflection hard coating film comprises a hard coating layer and a low-reflection layer sequentially stacked on a substrate layer, wherein the optical film thickness of the low-reflection layer is from 0.670λ to 0.825λ relative to a design wavelength (λ), and the water contact angle of the low-reflection layer is 100° or more. In particular, the optical film thickness of the low-reflection layer is expressed by Formula 1 below.

[0040] [Formula 1]

[0041] The thickness of the low-reflectivity optical film = n × d

[0042] In Equation 1 above,

[0043] n is the refractive index of the low-reflection layer, ranging from 1.38 to 1.50; d is the physical film thickness of the low-reflection layer.

[0044] The embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. However, the accompanying drawings are only for illustrating preferred embodiments of the present invention and, together with the foregoing description, serve to help further understand the technical concept of the present invention. Therefore, the present invention should not be construed as being limited to the matters depicted in the drawings.

[0045] The terminology used in this specification is for illustrative purposes and is not intended to limit the invention. In this specification, the singular form includes the plural form unless the context otherwise requires.

[0046] The terms "comprises" and / or "comprising" as used in this specification are used to mean that they do not exclude the presence or addition of more than one other component, step, operation, and / or element besides those mentioned. Throughout this specification, the same reference numerals refer to the same components.

[0047] As illustrated in the accompanying drawings, spatially relative terms such as "below," "bottom," "lower part," "above," "upper surface," and "upper part" are used to readily describe the relationship between one element or component and another. Spatially relative terms should be understood to include, in addition to the directions shown in the drawings, terms indicating the different orientations of the elements during use or operation. For example, when the elements illustrated in the accompanying drawings are flipped, an element described as being "below" or "lower" of another element can be placed "above" the other element. Therefore, the exemplary term "below" can encompass both the above and below directions. Elements can also face other directions, so spatially relative terms can be interpreted according to orientation.

[0048] In this specification, the term "transparent" as used in relation to the properties of a film or layer may refer to a visible light transmittance of 80%, 85%, 90%, or 95% or higher.

[0049] Low-reflection hard coating

[0050] Figure 1 This is a diagram illustrating the laminated structure of a low-reflection hard coating film according to an embodiment of the present invention.

[0051] Reference Figure 1 In one embodiment of the present invention, the low-reflection hard coating 100 may include a substrate layer 10, a hard coating layer 20, and a low-reflection layer 30.

[0052] The substrate layer 10 serves to provide a structural base for the constituent elements that constitute the low-reflection hard coating 100.

[0053] The composition of the substrate layer 10 is not particularly limited as long as the substrate layer 10 is transparent or light-transmitting. For example, the substrate layer may contain glass or polymer resin components. In one embodiment, the substrate layer 10 may have flexible properties, in which case the substrate layer 10 preferably contains polymer resin components.

[0054] In one or more embodiments, the substrate layer 10 may comprise a film formed from polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate; polyimide resins; acrylic resins such as poly(methyl methacrylate); styrene resins such as polystyrene and acrylonitrile-styrene; polycarbonate resins; polylactic acid resins; polyurethane resins; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; cycloolefin resins; vinyl resins such as polyvinyl chloride and polyvinylidene chloride; polyamide resins; sulfone resins; polyether-etherketone resins; allyl compounds; cellulose resins such as cellulose triacetate; or mixtures of the above resins, but is not limited thereto.

[0055] In another embodiment, the substrate layer may have a structure of two or more of the films listed above.

[0056] Since the refractive index of the substrate layer 10 has little effect on the low-reflection characteristics of the low-reflection hard coating film 100, the refractive index of the substrate layer 10 is not particularly limited, for example, it can be appropriately selected in the range of 1 to 2.5.

[0057] The thickness of the substrate layer 10 is not particularly limited. For example, the substrate layer 10 can have a thickness ranging from 10 to 250 μm. Specifically, the substrate layer 10 can have a thickness of 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, or 70 μm or more, and can have a thickness of less than 200 μm, 180 μm or less, 160 μm or less, 140 μm or less, 120 μm or less, or 100 μm or less. When the thickness is within the above range, the substrate layer 10 can ensure appropriate strength as a support and, depending on the circumstances, can ensure an appropriate level of flexibility.

[0058] In one embodiment, the substrate layer 10 may be surface-treated. For example, the substrate layer 10 may be subjected to sputtering, corona discharge, ultraviolet irradiation, acid / alkali treatment, primer treatment, etc. Such surface treatment can improve the adhesion of the substrate layer 10 to adjacent layers, such as the hard coating 20.

[0059] The hard coating 20 serves to impart a predetermined hardness to the low-reflection hard coating 100.

[0060] The hard coating 20 comprises a cured hard coating composition, which may include a light-transmitting resin, a photopolymerization initiator, and a solvent.

[0061] The light-transparent resin may contain a UV-curable (meth)acrylate oligomer or (meth)acrylate monomer.

[0062] The photocurable (meth)acrylate oligomer can be a commercially available epoxy (meth)acrylate oligomer, urethane (meth)acrylate oligomer, etc., preferably containing urethane (meth)acrylate oligomer.

[0063] The urethane (meth)acrylate oligomer can be any oligomer used in the art without limitation, but preferably it can be a product obtained by urethane esterification of a polyfunctional (meth)acrylate with an intramolecular hydroxyl group and a compound having an isocyanate group in the presence of a catalyst.

[0064] Specific examples of (meth)acrylates having hydroxyl groups within the molecule include 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone ring-opening hydroxyacrylate, pentaerythritol tri / tetra(meth)acrylate mixtures, and dipentaerythritol penta / hexa(meth)acrylate mixtures, but are not limited thereto. They can be used individually or in combination of two or more.

[0065] Specific examples of compounds having an isocyanate group include 1,4-diisocyanate butane, 1,6-diisocyanate hexane, 1,8-diisocyanate octane, 1,12-diisocyanate dodecane, 1,5-diisocyanate-2-methylpentane, trimethyl-1,6-diisocyanate hexane, 1,3-bis(isocyanate methyl)cyclohexane, trans-1,4-cyclohexene diisocyanate, 4,4'-methylene bis(cyclohexyl isocyanate), isophorone diisocyanate, and so on. Benzene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethylxylene-1,3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenylisocyanate), 4,4'-oxobis(phenylisocyanate), trifunctional isocyanates derived from hexamethylene diisocyanate, and trimethylpropanol addition to toluene diisocyanate, etc., but not limited to these, can be used alone or in combination of two or more.

[0066] The photocurable (meth)acrylate monomer refers to a monomer with unsaturated groups such as (meth)acryloyl, vinyl, styrene, and allyl as photocurable functional groups in its molecule, preferably containing (meth)acryloyl.

[0067] As mentioned above, monomers containing (meth)acryloyl groups include neopentyl glycol acrylate, 1,6-hexanediol (meth)acrylate, propylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1,2,4-cyclohexanetetra(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and pentaerythritol tri(meth)acrylate. Acrylates, dipentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tri(meth)acrylate, tripentaerythritol hexa(meth)acrylate, hydroxybutyl methacrylate, isooctyl methacrylate, isodecyl methacrylate, stearyl methacrylate, tetrahydrofurfuryl methacrylate, phenoxyethyl methacrylate, isobornyl methacrylate, etc., but not limited to these, and they can be used alone or in combination of two or more.

[0068] The content of the light-transmitting resin is not particularly limited in this invention, but it can be 1 to 80% by weight relative to 100% by weight of the total hard coating composition containing the resin. When the content of the light-transmitting resin is below the above range, it is difficult to sufficiently improve the hardness; when it exceeds the above range, there is a serious problem of curling.

[0069] The photopolymerization initiator serves to transform the liquid hard coating composition into a solid state. Any photopolymerization initiator used in the art can be used without special restrictions.

[0070] Specifically, examples include hydroxy ketones, amino ketones, and hydrogen-abstracting photopolymerization initiators. More specifically, examples include 2-methyl-1-[4-(methylthio)phenyl]2-morpholinoacetone-1, benzophenone, benzoylayldimethyl ketal, 2-hydroxy-2-methyl-1-phenyl-1-one, 4-hydroxycyclophenyl ketone, 2,2-dimethoxy-2-phenyl-acetophenone, anthraquinone, fluorene, triphenylamine, carbazole, 3-methylacetophenone, 4-chloroacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexylphenyl ketone, benzophenone, and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide. However, these are not limited to these examples, and they can be used individually or in combination of two or more.

[0071] The content of the photopolymerization initiator is not particularly limited in this invention, but it may be 0.1 to 10% by weight, preferably 1 to 5% by weight, relative to 100% of the total hard coating composition containing the initiator. When the content of the photopolymerization initiator is below the above range, the curing speed of the composition is slow, and incomplete curing may occur, resulting in a decrease in the mechanical properties of the hard coating; when it exceeds the above range, over-curing may cause cracks in the hard coating.

[0072] The solvent can dissolve or disperse the aforementioned components, and any solvent used as a solvent in the art can be used without special restrictions.

[0073] The solvents specifically used may preferably be alcohols (methanol, ethanol, isopropanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), acetates (ethyl acetate, propyl acetate, n-butyl acetate, tert-butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate, etc.), hexanes (hexane, heptane, octane, etc.), benzenes (benzene, toluene, xylene, etc.), and ethers (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, etc.), but are not limited to these, and two or more of them may be used individually or in combination.

[0074] The content of the solvent is not particularly limited in this invention, but it can be 10 to 95% by weight relative to 100% by weight of the total hard coating composition containing the solvent. When the content of the solvent is below the above range, not only is the viscosity high, resulting in decreased workability, but the substrate layer cannot be sufficiently swollen; when it exceeds the above range, the drying process consumes a lot of time, reducing economy, and the substrate layer may swell severely, resulting in haze.

[0075] Furthermore, the hard coating composition of the present invention may further include other polymer compounds, curing agents, leveling agents, adhesion promoters, antioxidants, ultraviolet absorbers, anti-gelling agents and other additives as needed.

[0076] In one embodiment, the refractive index of the hard coating 20 may be 1.50 to 1.60, which may have advantages in terms of being able to further improve the low-reflection characteristics of the low-reflection hard coating.

[0077] The thickness of the hard coating 20 is not particularly limited. For example, the hard coating 20 can have a thickness of 3 to 100 μm, preferably in the range of 5 to 50 μm. Specifically, the hard coating 20 can have a thickness of 3 μm or more, 4 μm or more, 5 μm or more, 6 μm or more, or 10 μm or more, and can have a thickness of less than 80 μm, 60 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less. When the thickness is within the above range, the hard coating 20 maintains flexibility while possessing excellent hardness, thereby preventing substantial curling.

[0078] The low-reflection layer 30 serves to impart low-reflection properties, as well as anti-fouling, abrasion-resistant, and scratch-resistant properties to the low-reflection hard coating 100.

[0079] The optical film thickness of the low-reflection layer 30, relative to the design wavelength (λ), can be from 0.670λ to 0.825λ. Furthermore, the optical film thickness of the low-reflection layer can be expressed by Equation 1 below.

[0080] [Formula 1]

[0081] The thickness of the low-reflectivity optical film = n × d

[0082] In Equation 1 above,

[0083] n is the refractive index of the low-reflection layer, and d can represent the physical film thickness of the low-reflection layer.

[0084] When the optical film thickness of the low-reflection layer 30 meets the above-mentioned range, the low-reflection layer can not only exhibit low-reflection characteristics, but also improve the wear resistance and scratch resistance of the low-reflection layer.

[0085] Specifically, when the optical film thickness of the low-reflection layer 30 is close to an even multiple of λ / 4 relative to the design wavelength (λ), the wavelengths of the reflected light R1 reflected from the surface of the low-reflection layer 30 and the reflected light R2 reflected at the interface between the low-reflection layer 30 and the hard coating 20 after passing through the low-reflection layer 30 are in a constructive interference relationship, resulting in a reduction in low-reflection characteristics. In contrast, when the optical film thickness of the low-reflection layer 30 is close to an odd multiple of λ / 4 relative to the design wavelength (λ), the wavelengths of the reflected light R1 reflected from the surface of the low-reflection layer 30 and the reflected light R2 reflected at the interface between the low-reflection layer 30 and the hard coating 20 after passing through the low-reflection layer 30 are in a destructive interference relationship, thus exhibiting low-reflection characteristics.

[0086] Based on this characteristic, the optical film thickness of the low-reflection layer has traditionally been designed to be λ / 4 to achieve low reflection properties. However, while this traditional low-reflection layer exhibits low reflection properties, it has limitations such as slightly poorer mechanical properties like scratch resistance and abrasion resistance.

[0087] In response, the inventors of this invention have continuously researched and developed a low-reflection layer that maintains the low-reflection characteristics of the low-reflection layer while improving mechanical properties, thus eliminating the need for a separate functional layer for improving mechanical properties, and which can itself be exposed to the outside of the device. As a result, it was confirmed that when the optical film thickness of the low-reflection layer is between 0.670λ and 0.825λ relative to the design wavelength (λ), both low-reflection characteristics are satisfied, and mechanical properties such as abrasion resistance and scratch resistance are improved. Specifically, it was confirmed that when the optical film thickness of the low-reflection layer is below the above range, there is a problem of decreased low-reflection characteristics and / or mechanical properties; when it exceeds the above range, there is a problem of decreased low-reflection characteristics or increased oscillation of the wavelength-reflectivity curve, resulting in an increased reflectivity deviation corresponding to the thickness.

[0088] In one embodiment, the design wavelength (λ) can be 380 to 780 nm, preferably 450 to 650 nm, and more preferably 550 nm. Furthermore, unless otherwise specified, the terms "refractive index," "transmittance," and "reflectance" used in this specification refer to values ​​measured at the aforementioned design wavelength (λ).

[0089] The refractive index n of the low-reflection layer 30 is not particularly limited, and can be set to satisfy the optical film thickness of the low-reflection layer 30 by considering the physical film thickness d of the low-reflection layer 30. For example, the refractive index n of the low-reflection layer 30 can be from 1.38 to 1.50, and in one or more embodiments, it can be 1.39 or higher, 1.41 or higher, 1.43 or higher, or 1.44 or higher, and can be 1.49 or lower or 1.48 or lower. When the refractive index of the low-reflection layer meets the above range, it has the advantage of effectively preventing light reflection caused by the difference in refractive index in relation to the hard coating layer disposed below the low-reflection layer.

[0090] The physical film thickness d of the low-reflection layer 30 is not particularly limited. The refractive index n of the low-reflection layer 30 can be considered to set the optical film thickness of the low-reflection layer 30 to meet the above requirements. For example, it can be 250 to 330 nm.

[0091] In addition to its low-reflection properties, the low-reflection layer 30 of the present invention also exhibits anti-fouling properties. In one embodiment, the water contact angle of the low-reflection layer 30 can be 100° or more, preferably 105° or more, more preferably 108° or more, and most preferably 110° or more. When the water contact angle of the low-reflection layer 30 meets the above range, it exhibits excellent anti-fouling properties and has the advantage of improving membrane durability when used in external environments.

[0092] Furthermore, the low-reflection layer 30 of the present invention can possess abrasion resistance as described above. In one embodiment, the water contact angle of the low-reflection layer 30 after being rubbed on its surface with an eraser under a 500g load for 3,000 cycles can be 100° or higher. When the water contact angle of the low-reflection layer 30 after abrasion resistance evaluation meets the above-mentioned range, it can maintain an excellent level of antifouling performance even when the low-reflection layer is continuously exposed to the outside of the device during use, thus having the advantage of maintaining performance during long-term use of the membrane.

[0093] Furthermore, the low-reflection layer 30 of the present invention can possess scratch resistance as described above. In one embodiment, the low-reflection layer 30 does not produce scratches even after being rubbed 30 times with steel wool (#0000) under a load of 250 g / cm². If the low-reflection layer 30 does not produce scratches after the above-described scratch resistance evaluation, it has advantages in protecting the film and internal components of the device from external friction when the low-reflection layer is used in the external environment of the device.

[0094] As described above, the low-reflection hard coating 100 of the present invention not only has low-reflection properties, but also exhibits excellent anti-fouling, abrasion resistance and scratch resistance. Therefore, even without a separate functional layer, such as a protective layer, to impart the above-mentioned functions, it can be directly exposed to the outside of the device for use.

[0095] The low-reflection layer 30 comprises a cured composition for forming a low-reflection layer, the composition comprising a fluorine-containing UV-curable functional compound, a light-transmitting resin, and inorganic nanoparticles, and may further comprise a photopolymerization initiator and a solvent.

[0096] The fluorine-containing UV-curable functional compound, as a component that imparts antifouling and abrasion resistance, is not particularly limited as long as it contains fluorine and simultaneously has UV-curable functional groups.

[0097] Specifically, the fluorine-containing UV-curable functional compound can be a compound containing one or more fluorine groups, such as (meth)acrylates containing one or more fluorine groups. Preferably, (meth)acrylates containing perfluorinated aliphatic groups or (meth)acrylates containing perfluorinated aromatic groups can be used. In this case, the fluorine-containing UV-curable functional compound more preferably has 1 to 6 UV-curable functional groups.

[0098] Examples include 2,2,2-trifluoroethyl acrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 2-perfluorobutylethyl acrylate, 3-perfluorobutyl-2-hydroxypropyl acrylate, 2-perfluorohexylethyl acrylate, 3-perfluorohexyl-2-hydroxypropyl acrylate, 2-perfluorooctylethyl acrylate, 3-perfluorooctyl-2-hydroxypropyl acrylate, 2-perfluorodecylethyl acrylate, and 2-perfluoro-3-methylbutylethyl acrylate. 3-Perfluoro-3-methoxybutyl-2-hydroxypropyl acrylate, 2-Perfluoro-5-methylhexylethyl acrylate, 3-Perfluoro-5-methylhexyl-2-hydroxypropyl acrylate, 2-Perfluoro-7-methyloctyl-2-hydroxypropyl acrylate, tetrafluoropropyl acrylate, octafluoropentyl acrylate, dodecafluoroheptyl acrylate, hexafluorononyl acrylate, hexafluorobutyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3,3- Pentafluoropropyl methacrylate, 2-perfluorobutylethyl methacrylate, 3-perfluorobutyl-2-hydroxypropyl methacrylate, 2-perfluorooctylethyl methacrylate, 3-perfluorooctyl-2-hydroxypropyl methacrylate, 2-perfluorodecylethyl methacrylate, 2-perfluoro-3-methylbutylethyl methacrylate, 3-perfluoro-3-methylbutyl-2-hydroxypropyl methacrylate, 2-perfluoro-5-methylhexylethyl methacrylate, 3- Perfluoro-5-methylhexyl-2-hydroxypropyl methacrylate, 2-perfluoro-7-methyloctylethyl methacrylate, 3-perfluoro-6-methyloctyl methacrylate, tetrafluoropropyl methacrylate, octafluoropentyl methacrylate, octafluoropentyl methacrylate, dodecafluoroheptyl methacrylate, hexadecylfluorononyl methacrylate, 1-trifluoromethyltrifluoroethyl methacrylate, hexafluorobutyl methacrylate, triacryloyl-heptafluorononenyl-pentaerythritol, etc.

[0099] Commercially available examples of fluorine-containing UV-curable functional group compounds that can be used in this invention include KY-1203 (Shin-Etsu Silicon Co., Ltd.), OPTOOL DAC-HP (Daikin Corporation), and UVAS-2003 (Sooyang Chemtec).

[0100] The content of the fluorine-containing UV-curable functional compound is not particularly limited in this invention, but it can be from 0.01 to 10% by weight relative to 100% of the total low-reflection layer forming composition containing the compound. For example, it can be 0.05% by weight or more, 0.1% by weight or more, 0.3% by weight or more, or 0.5% by weight or more, and it can be 8% by weight or less, 6% by weight or less, 4% by weight or less, or 2% by weight or less. When the content of the fluorine-containing UV-curable functional compound is lower than the above range, it is difficult to achieve sufficient antifouling and abrasion resistance; when it exceeds the above range, the film hardness and scratch resistance may decrease.

[0101] The light-transparent resin may contain a UV-curable (meth)acrylate oligomer or (meth)acrylate monomer.

[0102] The photocurable (meth)acrylate oligomer can be a commercially available epoxy (meth)acrylate oligomer, urethane (meth)acrylate oligomer, etc., preferably containing urethane (meth)acrylate oligomer.

[0103] The urethane (meth)acrylate oligomer can be any oligomer used in the art without limitation, but preferably it can be a product obtained by urethane esterification of a polyfunctional (meth)acrylate with an intramolecular hydroxyl group and a compound having an isocyanate group in the presence of a catalyst.

[0104] Specific examples of (meth)acrylates having hydroxyl groups within the molecule include 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone ring-opening hydroxyacrylate, pentaerythritol tri / tetra(meth)acrylate mixtures, and dipentaerythritol penta / hexa(meth)acrylate mixtures, but are not limited thereto. They can be used individually or in combination of two or more.

[0105] Specific examples of compounds having an isocyanate group include 1,4-diisocyanate butane, 1,6-diisocyanate hexane, 1,8-diisocyanate octane, 1,12-diisocyanate dodecane, 1,5-diisocyanate-2-methylpentane, trimethyl-1,6-diisocyanate hexane, 1,3-bis(isocyanate methyl)cyclohexane, trans-1,4-cyclohexene diisocyanate, 4,4'-methylene bis(cyclohexyl isocyanate), isophorone diisocyanate, and so on. Benzene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethylxylene-1,3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenylisocyanate), 4,4'-oxobis(phenylisocyanate), trifunctional isocyanates derived from hexamethylene diisocyanate, and trimethylpropanol addition to toluene diisocyanate, etc., but not limited to these, can be used alone or in combination of two or more.

[0106] The photocurable (meth)acrylate monomer refers to a monomer with unsaturated groups such as (meth)acryloyl, vinyl, styrene, and allyl as photocurable functional groups in its molecule, preferably containing (meth)acryloyl.

[0107] As mentioned above, monomers containing (meth)acryloyl groups include neopentyl glycol acrylate, 1,6-hexanediol (meth)acrylate, propylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1,2,4-cyclohexanetetra(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and pentaerythritol tri(meth)acrylate. Acrylates, dipentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tri(meth)acrylate, tripentaerythritol hexa(meth)acrylate, hydroxybutyl methacrylate, isooctyl methacrylate, isodecyl methacrylate, stearyl methacrylate, tetrahydrofurfuryl methacrylate, phenoxyethyl methacrylate, isobornyl methacrylate, etc., but not limited to these, and they can be used alone or in combination of two or more.

[0108] The content of the light-transmitting resin is not particularly limited in this invention, but it can be 1 to 80% by weight relative to 100% by weight of the total low-reflection layer forming composition containing the resin. For example, it can be 1.3% by weight or more, 1.5% by weight or more, 1.7% by weight or more, 2.0% by weight or more, or 2.5% by weight or more, and it can be 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, or 20% by weight or less. When the content of the light-transmitting resin is below the above range, it is difficult to sufficiently improve the hardness; when it exceeds the above range, there is a serious problem of curling.

[0109] The inorganic nanoparticles refer to inorganic particles with diameters in nanometers (nm) or micrometers (μm).

[0110] The inorganic nanoparticles may include hollow inorganic nanoparticles and / or solid inorganic nanoparticles.

[0111] Hollow inorganic nanoparticles refer to particles with empty spaces on their surface and / or inside.

[0112] There is no particular limitation on the average particle size of the hollow inorganic nanoparticles. For example, the hollow inorganic nanoparticles can have an average particle size in the range of 1 to 200 nm. Specifically, the hollow inorganic nanoparticles can have an average particle size of 5 nm or more, 6 nm or more, 8 nm or more, or 10 nm or more, and can have an average particle size of less than 180 nm, 160 nm or less, 140 nm or less, or 120 nm. When the average particle size is within the above range, the refractive index of the low-reflection layer can be reduced, and the anti-reflection properties can be improved.

[0113] In one embodiment, the hollow inorganic nanoparticles can be used alone, with their surfaces coated with fluorine-based compounds, or in combination with hollow inorganic nanoparticles whose surfaces are not coated with fluorine-based compounds. Coating the surface of the hollow inorganic nanoparticles with fluorine-based compounds can further reduce the surface energy, thereby further improving the durability or scratch resistance of the low-reflection layer.

[0114] The method of coating the surface of the hollow inorganic nanoparticles with fluorine compounds can be used without much limitation with commonly known particle coating methods or polymerization methods. For example, the hollow inorganic nanoparticles and fluorine compounds can undergo a sol-gel reaction in the presence of water and a catalyst, and the fluorine compounds can be bound to the surface of the hollow inorganic nanoparticles through hydrolysis and condensation reactions.

[0115] As a specific example of the hollow inorganic nanoparticles, hollow silica particles can be cited. To facilitate dispersion in organic solvents, the hollow silica may contain predetermined substituted functional groups on its surface. Examples of organic functional groups that can substitute on the surface of the hollow silica particles are not particularly limited; for example, (meth)acrylate groups, vinyl groups, hydroxyl groups, amino groups, allyl groups, epoxy groups, isocyanate groups, amino groups, or fluorine groups can be substituted on the surface of the hollow silica.

[0116] The refractive index of the hollow inorganic nanoparticles can be from 1.17 to 1.40. Specifically, the refractive index of the hollow inorganic nanoparticles can be 1.18 or higher, 1.19 or higher, 1.20 or higher, or 1.21 or higher, and can be 1.38 or lower, 1.36 or lower, 1.35 or lower, 1.33 or lower, or 1.30 or lower. The refractive index of the hollow inorganic nanoparticles does not refer to the refractive index of the shell forming the hollow particles, but can refer to the refractive index of the particle as a whole.

[0117] The content of the hollow inorganic nanoparticles is not particularly limited in this invention, but it can be from 0.1 to 35% by weight relative to 100% of the total composition for forming a low-reflection layer containing the particles. For example, it can be 0.5% or more, 1% or more, 2% or more, 3% or more, or 4% or more, and it can be less than 25% by weight, less than 20% by weight, less than 15% by weight, less than 10% by weight, or less than 5% by weight. When the content of the hollow inorganic nanoparticles exceeds the above range, the scratch resistance or abrasion resistance of the low-reflection layer may decrease.

[0118] Solid inorganic nanoparticles refer to particles that do not have empty spaces inside.

[0119] There is no particular limitation on the average particle size of the solid inorganic nanoparticles. For example, the solid inorganic nanoparticles can have an average particle size in the range of 0.1 to 100 nm. Specifically, the solid inorganic nanoparticles can have an average particle size of 0.5 nm or more, 1 nm or more, 2 nm or more, or 5 nm or more, and can have an average particle size of 95 nm or less, 90 nm or less, 85 nm or less, or 80 nm or less. When the average particle size is within the above range, agglomeration within the composition can be prevented, thereby enabling the formation of a uniform coating film, which in turn prevents a decrease in mechanical properties and enhances the hardness of the low-reflection layer.

[0120] The content of the solid inorganic nanoparticles is not particularly limited in this invention, but it can be from 0.1 to 35% by weight relative to 100% of the total composition for forming a low-reflection layer containing the particles. For example, it can be 0.5% or more, 1% or more, 1.5% or more, or 2% or more, and it can be less than 25% by weight, less than 20% by weight, less than 15% by weight, less than 10% by weight, or less than 5% by weight. When the content of the solid inorganic nanoparticles exceeds the above range, the scratch resistance or abrasion resistance of the low-reflection layer may decrease.

[0121] In one embodiment, the surfaces of both the hollow and solid inorganic nanoparticles may contain one or more reactive functional groups selected from the group consisting of (meth)acrylate, epoxy, vinyl, and thiol groups. Because the surfaces of both the hollow and solid inorganic nanoparticles contain these reactive functional groups, the low-reflectivity layer can have a higher degree of cross-linking, thereby ensuring further improved scratch resistance and stain resistance.

[0122] In one embodiment, when the inorganic nanoparticles simultaneously comprise hollow and solid inorganic nanoparticles, their content is not particularly limited in this invention. However, relative to 100% by weight of the total low-reflection layer forming composition containing the particles, it can be from 0.1% to 35% by weight, for example, it can be 0.5% by weight or more, 1% by weight or more, 1.5% by weight or more, or 2% by weight or more, and it can be 25% by weight or less, 20% by weight or less, 15% by weight or less, or 10% by weight or less. When the content of the inorganic nanoparticles exceeds the above range, the scratch resistance or abrasion resistance of the low-reflection layer may decrease.

[0123] The photopolymerization initiator serves to transform the liquid low-reflection layer formation composition into a solid state. Any photopolymerization initiator used in the art can be used without special restrictions.

[0124] Specifically, examples include hydroxy ketones, amino ketones, and hydrogen-abstracting photopolymerization initiators. More specifically, examples include 2-methyl-1-[4-(methylthio)phenyl]2-morpholinoacetone-1, benzophenone, benzoylayldimethyl ketal, 2-hydroxy-2-methyl-1-phenyl-1-one, 4-hydroxycyclophenyl ketone, 2,2-dimethoxy-2-phenyl-acetophenone, anthraquinone, fluorene, triphenylamine, carbazole, 3-methylacetophenone, 4-chloroacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexylphenyl ketone, benzophenone, and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide. However, these are not limited to these examples, and they can be used individually or in combination of two or more.

[0125] The content of the photopolymerization initiator is not particularly limited in this invention, but it can be 0.05 to 10% by weight relative to 100% of the total low-reflectivity layer forming composition containing the initiator. For example, it can be 0.06% by weight or more, 0.08% by weight or more, 0.1% by weight or more, or 0.2% by weight or more, and it can be 8% by weight or less, 5% by weight or less, 3% by weight or less, or 1% by weight or less. When the content of the photopolymerization initiator is below the above range, the curing speed of the composition is slow, and incomplete curing may occur, resulting in a decrease in the mechanical properties of the hard coating. When it exceeds the above range, over-curing may cause cracks in the low-reflectivity layer.

[0126] The solvent can dissolve or disperse the aforementioned components, and any solvent used as a solvent in the art can be used without special restrictions.

[0127] The solvents specifically used may preferably be alcohols (methanol, ethanol, isopropanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), acetates (ethyl acetate, propyl acetate, n-butyl acetate, tert-butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate, etc.), hexanes (hexane, heptane, octane, etc.), benzenes (benzene, toluene, xylene, etc.), and ethers (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, etc.), but are not limited to these, and two or more of them may be used individually or in combination.

[0128] The content of the solvent is not particularly limited in this invention, but it can be 10 to 95% by weight relative to 100% of the total low-reflection layer forming composition containing the solvent. For example, it can be 20% or more by weight, 35% or more by weight, 50% or more by weight, 65% or more by weight, or 80% or more by weight, and it can be 93% or less by weight, 91% or less by weight, or 89% or less by weight. When the content of the solvent is below the above range, not only is the viscosity high, leading to decreased workability, but the swelling of the underlying substrate cannot be sufficiently achieved. When it exceeds the above range, the drying process consumes a lot of time, reducing economic efficiency, and the swelling of the underlying substrate may be severe, leading to haze.

[0129] Furthermore, the low-reflection layer forming composition of the present invention may further include other polymer compounds, curing agents, leveling agents, adhesion promoters, antioxidants, ultraviolet absorbers, anti-condensation agents and other additives as needed.

[0130] In one embodiment of the present invention, the light transmittance of the low-reflection hard coating film can be 90% or more, and the reflectance can be 3.5% or less, more preferably 3.3% or less. Furthermore, the haze of the low-reflection hard coating film in one embodiment can be 1% or less, more preferably 0.8% or less. In this case, when used in a display area such as an image display device, it has the advantage of achieving low-reflection characteristics without reducing the visibility of the image.

[0131] In one embodiment, the low-reflection hard coating film 100 can be manufactured by sequentially applying a hard coating composition to the upper surface of the substrate layer 10 and curing it to form a hard coating layer 20, and applying a low-reflection layer forming composition to the upper surface of the hard coating layer 20 and curing it to form a low-reflection layer 30.

[0132] The specific method and conditions for forming the hard coating 20 and the low-reflection layer 30 can be adopted using methods commonly used in the art, and are not particularly limited in this invention. For example, after applying the hard coating composition or the low-reflection layer forming composition, the mixture can be dried by evaporation of volatiles at a temperature of 30 to 150°C for 10 seconds to 1 hour, specifically 30 seconds to 10 minutes, followed by UV curing to form the hard coating 20 or the low-reflection layer 30. In this case, the UV light irradiation dose can be approximately 100 to 2,000 mJ / cm², specifically 200 to 1,000 mJ / cm².

[0133] <Image display device>

[0134] The present invention includes an image display device comprising the above-described low-reflection hard coating.

[0135] Specific examples of the image display device may include liquid crystal display devices, electroluminescent display devices, plasma display devices, field emission display devices, etc.

[0136] In one embodiment, the image display device can use the aforementioned low-reflection hard coating as a front cover film. In this case, not only can the device be made thinner, but it can also exhibit excellent anti-fouling properties and durability.

[0137] Implementation of the invention

[0138] To aid in understanding the present invention, experimental examples including specific embodiments and comparative examples are provided below. However, these are merely illustrative and not intended to limit the appended claims. Various changes and modifications to the embodiments within the scope and technical concept of the present invention will be readily apparent to those skilled in the art, and these variations and modifications naturally fall within the scope of the appended claims. Furthermore, unless otherwise stated, the terms "%" and "parts" used below to indicate content are by weight.

[0139] Manufacturing example

[0140] Manufacturing Example 1: Manufacturing of Hard Coating Composition A

[0141] 16 parts by weight of 5-functional acrylate (Miramer M500, Miramer Specialty Chemicals), 16 parts by weight of 6-functional acrylate (Miramer M600, Miramer Specialty Chemicals), 65 parts by weight of propylene glycol monomethyl ether, 2.5 parts by weight of 1-hydroxycyclohexylphenyl ketone, and 0.5 parts by weight of silicone leveling agent (BYK, BYK-UV3530) were mixed in a mixer and filtered through a PP filter to obtain hard coating composition A.

[0142] Manufacturing Example 2: Manufacturing of Hard Coating Composition B

[0143] 16 parts by weight of 5-functional acrylate (Miramer M500, Miramer Specialty Chemicals), 16 parts by weight of 6-functional acrylate (Miramer M600, Miramer Specialty Chemicals), 15 parts by weight of propylene glycol monomethyl ether, 2.5 parts by weight of 1-hydroxycyclohexylphenyl ketone, 0.5 parts by weight of silicone leveling agent (BYK, BYK-UV3530), and 50 parts by weight of zirconium oxide dispersion (10nm, 30% solids) were mixed using a mixer and filtered through a PP filter to obtain hard coating composition B.

[0144] Manufacturing Example 3: Manufacturing of Composition A for Forming a Low-Reflection Layer

[0145] Composition A for forming a low-reflection layer was prepared by mixing 2.5 parts by weight of hexafunctional urethane acrylate (Kyoei Co., Ltd., UA-306I), 88.3 parts by weight of methyl ethyl ketone, 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone, 1.1 parts by weight of fluorine-containing UV-curable functional compound (Daikin Corporation, DAC-HP), 4 parts by weight of hollow silica (60 nm), and 3.9 parts by weight of nanoparticle silica sol (80 nm, 40% solids) dispersed in methyl ethyl ketone using a mixer and filtering the mixture using a PP filter.

[0146] Manufacturing Example 4: Manufacturing of Composition B for Forming a Low-Reflection Layer

[0147] Composition B for forming a low-reflection layer was prepared by mixing 2.9 parts by weight of hexafunctional urethane acrylate (Kyoei Co., Ltd., UA-306I), 88.9 parts by weight of methyl ethyl ketone, 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone, 1.1 parts by weight of fluorine-containing UV-curable functional compound (Daikin Corporation, DAC-HP), 4 parts by weight of hollow silica (60 nm), and 2.9 parts by weight of nanoparticle silica sol (80 nm, 40% solids) dispersed in methyl ethyl ketone using a mixer and filtering the mixture using a PP filter.

[0148] Manufacturing Example 5: Manufacturing of Composition C for Forming a Low-Reflection Layer

[0149] Composition C for forming a low-reflection layer was prepared by mixing 0.4 parts by weight of hexafunctional urethane acrylate (Kyoei Co., Ltd., UA-306I), 85.5 parts by weight of methyl ethyl ketone, 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone, 1.1 parts by weight of fluorine-containing UV-curable functional compound (Daikin Corporation, DAC-HP), 4 parts by weight of hollow silica (60 nm), and 8.8 parts by weight of nanoparticle silica sol (80 nm, 40% solids) dispersed in methyl ethyl ketone using a mixer and filtering the mixture using a PP filter.

[0150] Manufacturing Example 6: Manufacturing of Composition D for Forming a Low-Reflection Layer

[0151] Composition D for forming a low-reflection layer was prepared by mixing 2.5 parts by weight of hexafunctional urethane acrylate (Kyoei Co., Ltd., UA-306I), 88.3 parts by weight of methyl ethyl ketone (MEK), 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone (1-hydroxycyclohexylphenyl ketone), 1.1 parts by weight of silicone leveling agent (BYK Corporation, BYK-UV3500), 4 parts by weight of hollow silica (60 nm), and 3.9 parts by weight of nanoparticle silica sol (80 nm, 40% solids) dispersed in MEK using a mixer and filtering the mixture using a PP filter.

[0152] Examples and Comparative Examples: Fabrication of Low-Reflection Hard Coatings

[0153] Example 1

[0154] The hard coating composition A of Manufacturing Example 1 was applied to polyethylene terephthalate (PET, 50 μm), cured to a thickness of 6 μm, and then dried by solvent and irradiated with UV cumulative light intensity of 500 mJ / cm² to form a hard coating layer. Then, the low-reflection layer forming composition A of Manufacturing Example 3 was applied to the hard coating layer, dried by solvent, and irradiated with UV cumulative light intensity of 500 mJ / cm² under a nitrogen atmosphere to form a low-reflection layer, thereby producing the low-reflection hard coating film of Example 1. The physical film thickness, refractive index, and optical film thickness of the low-reflection layer are shown in Table 1 below.

[0155] Example 2

[0156] The hard coating composition A of Manufacturing Example 1 was applied to polyethylene terephthalate (PET, 50 μm), cured to a thickness of 6 μm, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² to form a hard coating layer. Then, the low-reflection layer forming composition B of Manufacturing Example 4 was applied to the hard coating layer, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² under a nitrogen atmosphere to form a low-reflection layer, thereby producing the low-reflection hard coating film of Example 2. The physical film thickness, refractive index, and optical film thickness of the low-reflection layer are shown in Table 1 below.

[0157] Example 3

[0158] The hard coating composition A of Manufacturing Example 1 was applied to polyethylene terephthalate (PET, 50 μm), cured to a thickness of 6 μm, and then dried by solvent and irradiated with UV cumulative light intensity of 500 mJ / cm² to form a hard coating layer. Then, the low-reflection layer forming composition A of Manufacturing Example 3 was applied to the hard coating layer, dried by solvent, and irradiated with UV cumulative light intensity of 500 mJ / cm² under a nitrogen atmosphere to form a low-reflection layer, thereby producing the low-reflection hard coating film of Example 3. The physical film thickness, refractive index, and optical film thickness of the low-reflection layer are shown in Table 1 below.

[0159] Example 4

[0160] The hard coating composition A of Manufacturing Example 1 was applied to polyethylene terephthalate (PET, 50 μm), cured to a thickness of 6 μm, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² to form a hard coating layer. Then, the low-reflection layer forming composition A of Manufacturing Example 3 was applied to the hard coating layer, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² under a nitrogen atmosphere to form a low-reflection layer, thereby producing the low-reflection hard coating film of Example 4. The physical film thickness, refractive index, and optical film thickness of the low-reflection layer are shown in Table 1 below.

[0161] Example 5

[0162] The hard coating composition A of Manufacturing Example 1 was applied to polyethylene terephthalate (PET, 50 μm), cured to a thickness of 6 μm, and then solvent-dried and irradiated with UV cumulative light intensity of 500 mJ / cm² to form a hard coating layer. Then, the low-reflection layer forming composition C of Manufacturing Example 5 was applied to the hard coating layer, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² under a nitrogen atmosphere to form a low-reflection layer, thereby producing the low-reflection hard coating film of Example 5. The physical film thickness, refractive index, and optical film thickness of the low-reflection layer are shown in Table 1 below.

[0163] Example 6

[0164] The hard coating composition B of Manufacturing Example 2 was applied to polyethylene terephthalate (PET, 50 μm), cured to a thickness of 6 μm, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² to form a hard coating layer. Then, the low-reflection layer forming composition A of Manufacturing Example 3 was applied to the hard coating layer, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² under a nitrogen atmosphere to form a low-reflection layer, thereby producing the low-reflection hard coating film of Example 6. The physical film thickness, refractive index, and optical film thickness of the low-reflection layer are shown in Table 1 below.

[0165] Comparative Example 1

[0166] The hard coating composition of Manufacturing Example 1 was applied to polyethylene terephthalate (PET, 50 μm), cured to a thickness of 6 μm, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² to form a hard coating layer. Then, the low-reflection layer forming composition A of Manufacturing Example 3 was applied to the hard coating layer, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² under a nitrogen atmosphere to form a low-reflection layer, thereby producing the low-reflection hard coating film of Comparative Example 1. The physical film thickness, refractive index, and optical film thickness of the low-reflection layer are shown in Table 1 below.

[0167] Comparative Example 2

[0168] The hard coating composition of Manufacturing Example 1 was applied to polyethylene terephthalate (PET, 50 μm), cured to a thickness of 6 μm, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² to form a hard coating layer. Then, the low-reflection layer forming composition A of Manufacturing Example 3 was applied to the hard coating layer, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² under a nitrogen atmosphere to form a low-reflection layer, thereby producing the low-reflection hard coating film of Comparative Example 2. The physical film thickness, refractive index, and optical film thickness of the low-reflection layer are shown in Table 1 below.

[0169] Comparative Example 3

[0170] The hard coating composition of Manufacturing Example 1 was applied to polyethylene terephthalate (PET, 50 μm), cured to a thickness of 6 μm, and then solvent-dried and irradiated with UV cumulative light intensity of 500 mJ / cm² to form a hard coating layer. Then, the low-reflection layer forming composition D of Manufacturing Example 6 was applied to the hard coating layer, solvent-dried, and irradiated with UV cumulative light intensity of 500 mJ / cm² under a nitrogen atmosphere to form a low-reflection layer, thereby producing the low-reflection hard coating film of Comparative Example 3. The physical film thickness, refractive index, and optical film thickness of the low-reflection layer are shown in Table 1 below.

[0171] [Table 1]

[0172]

[0173] Experimental Example: Property Evaluation of Low-Reflection Hard Coatings

[0174] (1) Haze measurement

[0175] The haze of the low-reflection hard coatings of the above-described embodiments and comparative examples was measured using a haze meter (HM-150, Murakami Corporation), and the results are shown in Table 2 below.

[0176] (2) Reflectivity measurement

[0177] After the low-reflection hard coatings of the above embodiments and comparative examples were laminated onto black acrylic plates to eliminate back reflection, the reflectance was measured using an integrating sphere reflectometer (CM-3700A, Konica Minolta), and the results are shown in Table 2 below.

[0178] (3) Scratch resistance evaluation

[0179] After fixing the substrate layer onto the glass with the low-reflection layer of the low-reflection hard coating film of the above embodiments and comparative examples facing upwards, the film surface was visually observed to see if scratches were generated after rubbing it 30 times with steel wool (#0000) at a load of 250g / cm². The results are shown in Table 2 below.

[0180] <Evaluation Criteria>

[0181] ○: No scratches were found.

[0182] △: The number of scratches is less than 20

[0183] X: More than 20 scratches were generated.

[0184] (4) Initial water contact angle measurement

[0185] The water contact angles of the low-reflection layers of the low-reflection hard coatings of the above embodiments and comparative examples were measured, and the results are shown in Table 2 below.

[0186] (5) Abrasion resistance evaluation

[0187] The water contact angle of the low-reflection layer surface of the low-reflection hard coating of the above embodiments and comparative examples was measured after applying a load of 500g and rubbing for 3000 cycles with an abrasion resistance test eraser. The results are shown in Table 2 below.

[0188] <Evaluation Criteria>

[0189] ○: The water contact angle after evaluation is above 100°.

[0190] X: Water contact angle less than 100° after evaluation

[0191] [Table 2]

[0192]

[0193] As can be seen from the table above, the low-reflection hard coating film according to the embodiments of the present invention has a reflectance of less than 3.22%, which not only has excellent low-reflection characteristics, but also has a water contact angle of more than 110.2°, excellent anti-fouling properties, and excellent scratch resistance and abrasion resistance.

[0194] On the other hand, it can be seen that in Comparative Example 1, which has the optical film thickness of the low-reflection layer that is present in conventional low-reflection films, even though the low-reflection characteristics are excellent, the scratch resistance and abrasion resistance are poor.

[0195] Furthermore, it can be seen that in Comparative Example 2, where the optical film thickness of the low-reflection layer is close to an even multiple of λ / 4 relative to the design wavelength (λ), not only are the low-reflection characteristics poor, but the scratch resistance and abrasion resistance are also poor.

[0196] Furthermore, it can be seen that in Comparative Example 3, which does not contain fluorine-containing UV-curable functional group compounds, the stain resistance, scratch resistance, and abrasion resistance are poor.

[0197] Therefore, the low-reflection hard coating of the present invention has the advantages of low reflectivity, excellent anti-fouling, scratch resistance and abrasion resistance, and does not require separate components and can be used on the outside of the equipment itself.

[0198] Industrial availability

[0199] The low-reflection hard coating of this invention not only possesses excellent low-reflection characteristics, but also eliminates the need for a separate functional layer to improve the mechanical properties or functionality of the low-reflection layer. It exhibits excellent anti-fouling, abrasion resistance, and scratch resistance, thus it can be used as a front cover film for image display devices. Therefore, the process of fabricating a separate functional layer can be omitted, improving process economy. Furthermore, the film is thinner than conventional films, offering advantages in achieving thinner image display devices and improving bending characteristics.

Claims

1. A low-reflection hard coat film, which has a hard coat layer and a low-reflection layer sequentially layered on a substrate layer, wherein the optical film thickness of the low-reflection layer is represented by the following formula 1, 0.670λ to 0.825λ with respect to a design wavelength λ, the water contact angle of the low-reflection layer is 100° or more, and the low-reflection layer does not contain a separate functional layer. [Formula 1] Low-reflection layer optical film thickness = n x d In the above formula 1, n is the refractive index of the low-reflection layer, and is 1.38 to 1.50; and d is the physical film thickness of the low-reflection layer.

2. The low-reflection hard coat film according to claim 1, wherein the design wavelength λ is 380 to 780 nm.

3. The low-reflection hard coat film according to claim 1, wherein the design wavelength λ is 550 nm.

4. The low-reflection hard coat film according to claim 1, wherein the water contact angle after a 3,000-time eraser abrasion test at a load of 500 g on the surface of the low-reflection layer is 100° or more.

5. The low-reflection hard coat film according to claim 1, wherein no scratch is generated when a 30-time steel wool test is performed at a load of 250 g / cm2on the surface of the low-reflection layer.

6. The low-reflection hard coat film according to claim 1, wherein the low-reflection layer does not contain a separate functional layer.

7. The low-reflection hard coat film according to claim 1, wherein the low-reflection layer contains a cured product of a low-reflection layer-forming composition, the low-reflection layer-forming composition containing a fluorine-containing UV-curable functional group compound, a light-transmissive resin, and inorganic nanoparticles.

8. The low-reflection hard coat film according to claim 7, wherein the inorganic nanoparticles contain any one of hollow inorganic nanoparticles and solid inorganic nanoparticles.

9. The low-reflection hard coat film according to claim 8, wherein the average particle diameter of the hollow inorganic nanoparticles is 1 to 200 nm, and the average particle diameter of the solid inorganic nanoparticles is 0.1 to 100 nm.

10. The low-reflection hard coat film according to claim 8, wherein the refractive index of the hollow inorganic nanoparticles is 1.17 to 1.

40.

11. The low-reflection hard coat film according to claim 7, wherein the low-reflection layer-forming composition contains, with respect to the total weight of the low-reflection layer-forming composition, 0.01 to 10% by weight of the fluorine-containing UV-curable functional group compound; 1 to 80% by weight of the light-transmissive resin; and 0.1 to 35% by weight of the inorganic nanoparticles.

12. The low-reflection hard coat film according to claim 1, wherein the light transmittance of the low-reflection hard coat film is 90% or more, and the reflectance is 3.5% or less.

13. The low-reflection hard coat film according to claim 1, wherein the haze of the low-reflection hard coat film is 1% or less.

14. An image display device comprising the low-reflection hard coat film according to any one of claims 1 to 13.

15. The image display device according to claim 14, wherein the low-reflection hard coat film is used as a front cover film of the image display device. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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