Hard coating film, and image display device equipped therewith

Abstract

To provide a hard coating film which is excellent in anti-fouling property, and has excellent abrasion resistance, scratch resistance and bending resistance, and an image display device provided with the hard coating film.SOLUTION: A hard coating film includes a base material and a hard coating layer formed on at least one surface of the base material, in which the hard coating layer is formed from a hard coating composition containing a hydroxy group-containing translucent resin, a fluorine-based UV curable type functional group-containing compound, a photoinitiator and a solvent, and when the surface of the hard coating layer is measured by X-ray photoelectron spectroscopy (XPS), a fluorine (F) element content of the hard coating layer is 10-55% with respect to 100% of the total elements.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a hard coating film and an image display device provided with the same. More specifically, the present invention relates to a hard coating film having excellent antifouling properties, excellent abrasion resistance, scratch resistance, and bending resistance, and an image display device provided with the hard coating film.

Background Art

[0002] Hard coating films are used for surface protection purposes in image display devices such as liquid crystal display devices, electroluminescence (EL) display devices, plasma displays (PDs), and field emission displays (FEDs).

[0003] In recent years, instead of existing non-flexible glass substrates, flexible display devices or foldable display devices that can maintain display performance even when bent like paper by using flexible materials such as plastic or ultra-thin glass (UTG) have emerged as next-generation display devices. Along with this, research has been conducted on hard coating films that not only have high hardness and excellent scratch resistance but also have sufficient bending resistance to be applicable to flexible display devices or foldable display devices without causing curling at the film edges during the manufacturing process and even during use, so that cracks do not occur.

[0004] Furthermore, when a hard coating film is often used by being disposed on the outermost periphery of a display, in addition to mechanical physical properties such as abrasion resistance and scratch resistance, antifouling properties related to resistance to and / or ease of removal of fingerprints, markers, etc. on the display are required as main performance.

[0005] Korean Published Patent No. 10-2005-0010064 relates to an object with a composite hard coating layer and a method for forming a composite hard coating layer, and more specifically, discloses an object to which a composite hard coating layer is provided, comprising a hard coating layer provided on the surface of the object and an antifouling surface layer provided on the surface of the hard coating layer, wherein the hard coating layer is made of a cured product of a hard coating agent composition containing an active energy ray curable compound, and the antifouling surface layer is made of a cured product of a surface material containing a polyfunctional (meth)acrylate compound containing fluoro and a monofunctional (meth)acrylate compound containing fluoro, and the antifouling surface layer is fixed to the hard coating layer, relating to an object to which a composite hard coating layer is provided.

[0006] However, in the case of the aforementioned technology, the process becomes complex because it is necessary to introduce a hard coating layer and an anti-fouling layer to the polymer substrate film, which leads to problems such as a decrease in yield and an increase in price due to increased process costs.

[0007] Furthermore, with the growing demand for ultra-thin displays, there is a need to develop hard coating films that feature a single layer of hard coating that provides not only abrasion resistance and scratch resistance, but also stain resistance. [Overview of the project] [Problems that the invention aims to solve]

[0008] One objective of the present invention is to provide a hard coating film that has excellent stain resistance, as well as excellent abrasion resistance, scratch resistance, and flexibility resistance.

[0009] Another object of the present invention is to provide an image display device equipped with the hard coating film. [Means for solving the problem]

[0010] On the other hand, the present invention relates to a base material, and A hard coating film comprising a hard coating layer formed on at least one surface of the substrate, The hard coating layer is formed from a hard coating composition comprising a hydroxyl group-containing translucent resin, a fluorine-based UV-curable functional group-containing compound, a photoinitiator, and a solvent. The present invention provides a hard coating film in which, when the surface of the hard coating layer is measured by X-ray photoelectron spectroscopy (XPS), the atomic percent of fluorine (F) on the surface of the hard coating layer is 10 to 55 at%.

[0011] In one embodiment of the present invention, the hydroxyl group-containing translucent resin may contain a hydroxyl group-containing (meth)acrylate compound.

[0012] In one embodiment of the present invention, the hydroxyl group-containing translucent resin may be included in an amount of 1 to 50% by weight relative to 100% by weight of the total hard coating composition.

[0013] In one embodiment of the present invention, the fluorine-based UV-curable functional group-containing compound may include one or more selected from the group consisting of (meth)acrylates containing perfluoroalkyl groups, (meth)acrylates containing perfluoropolyether groups, (meth)acrylates containing perfluorocyclic aliphatic groups, and (meth)acrylates containing perfluoroaromatic groups.

[0014] In one embodiment of the present invention, the fluorine-based UV-curable functional group-containing compound may be present in an amount of 1 to 40% by weight relative to 100% by weight of the total hard coating composition.

[0015] In one embodiment of the present invention, the hard coating layer may have a water contact angle of 100° or more after being rubbed 3000 times with an eraser and a weight under a load of 1 kg.

[0016] On the other hand, the present invention provides an image display device equipped with the hard coating film.

[0017] On the other hand, the present invention also provides a window for a flexible display device equipped with the hard coating film. On the other hand, the present invention also provides a polarizing plate equipped with the hard coating film.

[0018] On the other hand, the present invention also provides a touch sensor equipped with the hard coating film. [Effects of the Invention]

[0019] The hard coating film according to the present invention is excellent in stain resistance, abrasion resistance, and scratch resistance by controlling the atomic percentage of fluorine (F) on the surface of the hard coating layer to a specific range using a hard coating composition containing a hydroxyl group-containing translucent resin and a fluorine-based UV-curable functional group-containing compound. Furthermore, the hard coating film according to one embodiment of the present invention has excellent flexibility, making it advantageously applicable to flexible or foldable display devices. [Modes for carrying out the invention]

[0020] The present invention will be described in more detail below.

[0021] One embodiment of the present invention is A hard coating film comprising a substrate and a hard coating layer formed on at least one surface of the substrate, The hard coating layer is formed from a hard coating composition comprising a hydroxyl group-containing translucent resin, a fluorine-based UV-curable functional group-containing compound, a photoinitiator, and a solvent. This invention relates to a hard coating film in which, when the surface of the hard coating layer is measured by X-ray photoelectron spectroscopy (XPS), the atomic percent of fluorine (F) on the surface of the hard coating layer is 10 to 55 at%.

[0022] The hard coating film according to an embodiment of the present invention forms a hard coating layer using a hard coating composition containing a hydroxy group-containing translucent resin and a fluorine-based UV-curable functional group-containing compound, thereby being excellent in antifouling property and wear resistance. Specifically, the hydroxy group of the hydroxy group-containing translucent resin repels the fluorine atom of the fluorine-based UV-curable functional group-containing compound so that the fluorine atom is oriented on the surface of the hard coating layer, and the atomic percentage of fluorine (F) element on the surface of the hard coating layer is controlled to a level of 10 to 55 at%, so that not only the antifouling property but also the wear resistance and scratch resistance can be exhibited. In particular, the hydroxy group-containing translucent resin can form a matrix of the hard coating layer by photocuring to improve the wear resistance of the hard coating layer.

[0023] Thereby, the hard coating film according to an embodiment of the present invention can include a hard coating layer that can exhibit antifouling property as a single layer in addition to wear resistance and scratch resistance, and can be advantageously applied to an ultra-thin display.

[0024] Furthermore, the hard coating film according to an embodiment of the present invention has excellent bend resistance such that even when the hard coating layer surface is inward and bent 200,000 times repeatedly with a curvature radius of 1 mm, no film breakage or peeling of the hard coating layer occurs, and thus can be advantageously applied to a flexible display device or a foldable display device.

[0025] In one embodiment of the present invention, the hard coating film has an atomic percentage of fluorine (F) on the surface of the hard coating layer, which is 10 to 55 at%, preferably 15 to 55 at%, and more preferably 15 to 50 at%, when the surface of the hard coating layer is measured by X-ray photoelectron spectroscopy (XPS). If the atomic percentage of fluorine (F) on the surface of the hard coating layer is less than 10 at%, the antifouling and abrasion resistance will not decrease, but if it exceeds 55 at%, the scratch resistance may decrease.

[0026] The atomic percentage of fluorine (F) on the surface of the hard coating layer is the value obtained by measuring the surface of the hard coating layer using X-ray photoelectron spectroscopy (XPS) according to the method described in the experimental example below.

[0027] A hard coating film according to one embodiment of the present invention includes a substrate and a hard coating layer formed on at least one surface of the substrate.

[0028] In one embodiment of the present invention, the substrate may be any substrate used in the art, and specifically, a film having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc., may be used. More specifically, the substrate may be a film made of thermoplastic resins such as polyester resins like polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; cellulosin resins like diacetylcellulose and triacetylcellulose; polycarbonate resins; acrylic resins like polymethyl (meth)acrylate and polyethyl (meth)acrylate; styrene resins like polystyrene and acrylonitrile-styrene copolymers; polyolefin resins like polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, and ethylene-propylene copolymers; vinyl chloride resins; amide resins like nylon and aromatic polyamides; imide resins; sulfone resins; polyethersulfone resins; polyetheretherketone resins; sulfurized polyphenylene resins; vinyl alcohol resins; vinylidene chloride resins; vinyl butyral resins; arylate resins; polyoxymethylene resins; and epoxy resins. A film made of a blend of the thermoplastic resins may also be used. Furthermore, films or UTG (ultra-thin glass) made of thermosetting resins such as (meth)acrylic, urethane, acrylic-urethane, epoxy, or silicone, or ultraviolet-curing resins may be used. According to one embodiment of the present invention, polyimide resins or polyester resins that have excellent durability against repeated bending and can be easily applied to flexible image display devices may be used.

[0029] The thickness of the substrate is not particularly limited, but may be between 8 and 1000 μm, specifically between 20 and 150 μm. If the thickness of the substrate is less than 8 μm, the strength of the film decreases and its processability deteriorates, and if it exceeds 1000 μm, problems arise such as decreased transparency and increased weight of the hard coating film.

[0030] In one embodiment of the present invention, the hard coating layer may be formed by applying a hard coating composition to at least one surface of the substrate.

[0031] Because the hard coating layer exhibits antifouling properties, if it is formed on the side of the substrate opposite to the visible side, it may be difficult to adhere to an optical layer or panel placed below it. Therefore, the hard coating layer may preferably be formed as a single layer on the visible side of the substrate.

[0032] In one embodiment of the present invention, the hard coating composition comprises a hydroxyl group-containing translucent resin, a fluorine-based UV-curable functional group-containing compound, a photoinitiator, and a solvent.

[0033] In one embodiment of the present invention, the hydroxyl group-containing translucent resin is a photocurable resin, and the photocurable resin may contain a hydroxyl group-containing (meth)acrylate compound.

[0034] Examples of the hydroxyl group-containing (meth)acrylate compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, 1,4-butanediol mono(meth)acrylate, 2-hydroxyalkyl (meth)acryloyl phosphate (where alkyl is, for example, methyl, ethyl, or propyl), 4-hydroxycyclohexyl (meth)acrylate, 1,6-hexanediol mono(meth)acrylate, neopentyl glycol mono(meth)acrylate, trimethylolpropanedi(meth)acrylate, trimethylolethanedi(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate, which may be used individually or in combination of two or more.

[0035] The hydroxyl group-containing translucent resin may be present in an amount of 1 to 50% by weight, preferably 5 to 50% by weight, relative to 100% by weight of the total hard coating composition. If the content of the hydroxyl group-containing translucent resin is less than 1% by weight, the abrasion resistance may be poor and it may be difficult to achieve sufficient hardness improvement, while if it exceeds 50% by weight, the problem of severe curling may occur. In one embodiment of the present invention, the fluorine-based UV-curable functional group-containing compound is a component that imparts antifouling, abrasion resistance, and chemical resistance. The fluorine-based UV-curable functional group-containing compound is not particularly limited as long as it contains fluorine and has a UV-curable functional group and can chemically bond with a hydroxyl group-containing translucent resin that forms the matrix of the hard coating layer.

[0036] The fluorine-based UV-curable functional group-containing compound may be one or more selected from the group consisting of (meth)acrylate containing a perfluoroalkyl group, (meth)acrylate containing a perfluoropolyether group, (meth)acrylate containing a perfluorocyclic aliphatic group, and (meth)acrylate containing a perfluoroaromatic group. This is preferable because it exhibits excellent antifouling performance and has the advantage of excellent durability, maintaining antifouling performance for a long time even after repeated use by forming a chemical bond with the hard coating layer.

[0037] The aforementioned fluorine-based UV-curable functional group-containing compound preferably has 1 to 6 UV-curable functional groups.

[0038] The fluorine-based UV-curable functional group-containing compound may be present in an amount of 1 to 40% by weight, preferably 2 to 40% by weight, and more preferably 10 to 40% by weight, based on 100% by weight of the total hard coating composition. It is preferable that the fluorine-based UV-curable functional group-containing compound is present within the above range, as this enables the provision of excellent abrasion resistance and antifouling effects. If the content of the UV-curable functional group-containing compound is below the above range, it may be difficult to obtain sufficient abrasion resistance or antifouling properties, and if it exceeds the above range, the hardness and / or scratch resistance may decrease.

[0039] In one embodiment of the present invention, the photoinitiator is included for photocuring induction of the hard coating composition and may include, for example, a photoradical initiator that can form radicals upon light irradiation.

[0040] Examples of the aforementioned photoinitiators include Type 1 initiators that generate radicals by decomposing molecules based on differences in chemical structure or molecular bond energy, and Type 2 initiators that induce hydrogen abstraction in coexistence with tertiary amines.

[0041] For example, the Type 1 initiator may include acetophenones such as 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-l-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-todecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, and 1-hydroxycyclohexylphenylketone; benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzyldimethyl ketal; phosphine oxides; and titanocene compounds.

[0042] For example, Type 2 initiators include benzophenones such as benzophenone, benzoylbenzoic acid, benzoylbenzoate methyl ether, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzene-4'-methyldiphenyl sulfite, and 3,3'-methyl-4-methoxybenzophenone; and thioxanthones such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, and isopropylthioxanthone.

[0043] The photoinitiators described above may be used individually or in combination of two or more. Furthermore, the Type 1 and Type 2 initiators may be used individually or in combination.

[0044] The photoinitiator may be present in an amount of about 0.1 to 10% by weight, preferably about 0.1 to 5% by weight, based on 100% by weight of the total hard coating composition. If the photoinitiator content is less than 0.1% by weight, sufficient curing may not proceed, and the mechanical properties and adhesion of the hard coating film or hard coating layer may not be ensured. If the photoinitiator content exceeds 10% by weight, poor adhesion, cracking, and curling may occur due to curing shrinkage.

[0045] In one embodiment of the present invention, the solvent may be any solvent known in the art that is capable of dissolving or dispersing the aforementioned composition. The solvent also plays a role in providing time for the fluorine-based UV-curable functional group-containing compound to float to the outermost surface of the coating layer due to the difference in surface tension during the process of applying the hard coating composition to the substrate and drying it.

[0046] Usable solvents include alcohol-based solvents (methanol, ethanol, isopropanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), ketone-based solvents (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), and acetate-based solvents (ethyl acetate, propyl acetate, n-butyl acetate, t-butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol) Preferably, solvents such as monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate, etc., hexane-based solvents (hexane, heptane, octane, etc.), benzene-based solvents (benzene, toluene, xylene, etc.), and ether-based solvents (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, etc.) may be used. The solvents exemplified above may be used individually or in combination of two or more.

[0047] The solvent may be present in an amount of 10 to 50% by weight, preferably 20 to 50% by weight, relative to 100% by weight of the total hard coating composition. If the solvent content is less than the aforementioned amount, the viscosity will be high, resulting in poor workability and insufficient swelling of the substrate. Conversely, if it exceeds the aforementioned range, the drying process will take a long time, resulting in poor economic efficiency. Therefore, the solvent should be used appropriately within the aforementioned range.

[0048] In one embodiment of the present invention, the hard coating composition may further contain other light-transmitting resins in addition to the hydroxyl group-containing light-transmitting resin.

[0049] The other translucent resins may include photocurable (meth)acrylate oligomers and / or monomers.

[0050] The aforementioned photocurable (meth)acrylate oligomer typically includes epoxy (meth)acrylate and urethane (meth)acrylate, with urethane (meth)acrylate being preferred. Urethane (meth)acrylate can be produced by reacting a (meth)acrylate having a hydroxyl group in its molecule with a compound having an isocyanate group in the presence of a catalyst. Specific examples of (meth)acrylates having a hydroxyl group in their molecule include 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone ring-opened hydroxyacrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Specific examples of compounds having the 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'-methylenebis(cyclohexyl isocyanate), isophorondi Examples include socyanates, toluene-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-dimethylphenyl isocyanate), 4,4'-oxybis(phenyl isocyanate), trifunctional isocyanates derived from hexamethylene diisocyanate, and toluene diisocyanate from trimethylolpropane adducts.

[0051] The monomers mentioned above may be any commonly used monomers without particular limitations, and monomers having an unsaturated group such as a (meth)acryloyl group, vinyl group, styryl group, or allyl group as a photocurable functional group within the molecule are preferred, and among these, monomers having a (meth)acryloyl group are preferred.

[0052] The monomer having a (meth)acryloyl group may be one or more selected from the group consisting of neopentyl glycol acrylate, 1,6-hexanediol di(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, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, isooctyl(meth)acrylate, isodecyl(meth)acrylate, stearyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, phenoxyethyl(meth)acrylate, and isoborneol(meth)acrylate, as specific examples.

[0053] The other translucent resins exemplified above, namely photocurable (meth)acrylate oligomers and monomers, may be used individually or in combination of two or more.

[0054] The aforementioned other translucent resins are not particularly limited, but may be included in an amount of 50% by weight or less, for example, 1 to 50% by weight, relative to 100% by weight of the total hard coating composition. If the aforementioned other translucent resins are included in an amount exceeding 50% by weight, it may become difficult to control the atomic percentage of fluorine (F) on the surface of the hard coating layer to a level of 10 to 55 at%, and problems such as severe curling may occur.

[0055] In addition to the components mentioned above, the hard coating composition may further contain components commonly used in the art, such as leveling agents, ultraviolet stabilizers, heat stabilizers, antioxidants, surfactants, lubricants, and antifouling agents.

[0056] The hard coating layer may be formed by applying the hard coating composition to one or both sides of the substrate, drying it, and then UV curing it.

[0057] The hard coating composition can be coated onto a substrate using known methods such as die coating, air knife, reverse roll, spray, blade, casting, gravure, microgravure, and spin coating.

[0058] After applying the hard coating composition to the substrate, the volatile matter is evaporated and dried at a temperature of 30 to 150°C for 10 seconds to 1 hour, more specifically, for 30 seconds to 30 minutes, and then cured by irradiation with UV light. The amount of UV light irradiated is specifically about 0.01 to 10 J / cm². 2 It is acceptable to have a density of 0.1 to 2 J / cm², more specifically, 0.1 to 2 J / cm². 2 That's fine.

[0059] In this case, the thickness of the formed hard coating layer may be specifically 2 to 30 μm, more specifically 3 to 20 μm, preferably 2 to 8 μm, and more preferably 2 to 7 μm. When the thickness of the hard coating layer falls within the above range, excellent hardness and flexibility can be obtained.

[0060] One embodiment of the present invention relates to an image display device equipped with the hard coating film described above. For example, the hard coating film according to the present invention may be used as a window for an image display device, particularly a flexible display device or a foldable display device. The hard coating film according to the present invention may also be used by attaching it to a polarizing plate, a touch sensor, particularly a polarizing plate for a flexible display device or a foldable display device, or a touch sensor.

[0061] The hard coating film according to one embodiment of the present invention may be used in reflective, transmissive, and semi-transmissive LCDs, or in LCDs of various driving modes such as TN type, STN type, OCB type, HAN type, VA type, and IPS type. Furthermore, the hard coating film according to one embodiment of the present invention may be used in various image display devices such as plasma displays, field emission displays, organic EL displays, inorganic EL displays, and electronic paper.

[0062] The present invention will be described in more detail below with reference to examples, comparative examples, and experimental examples. It should be noted that these examples, comparative examples, and experimental examples are merely for illustrative purposes, and it will be obvious to those skilled in the art that the scope of the present invention is not limited thereto.

[0063] Manufacturing Examples and Comparative Manufacturing Examples: Manufacturing of Hard Coating Compositions The components shown in Tables 1 and 2 below were mixed using a stirrer, and the mixture was filtered using a PP filter to produce hard coating compositions (by weight %).

[0064] [Table 1]

[0065] [Table 2]

[0066] Example 1: Manufacturing of a hard coating film The hard coating composition of Production Example 1 was coated onto a polyester film (PET, 50 μm) to a cured thickness of 5 μm, and after drying the solvent, it was subjected to a UV integrated light intensity of 600 mJ / cm² under a nitrogen atmosphere. 2 A hard coating film was manufactured by irradiating it with light.

[0067] Example 2: Manufacturing of a hard coating film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Production Example 2 was used instead of the hard coating composition of Production Example 1.

[0068] Example 3: Manufacturing of a hard coating film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Production Example 3 was used instead of the hard coating composition of Production Example 1.

[0069] Example 4: Manufacturing of a hard coating film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Production Example 4 was used instead of the hard coating composition of Production Example 1.

[0070] Example 5: Manufacturing of a hard coating film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Production Example 5 was used instead of the hard coating composition of Production Example 1.

[0071] Example 6: Manufacturing of a hard coating film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Production Example 6 was used instead of the hard coating composition of Production Example 1.

[0072] Example 7: Manufacturing of a hard coating film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Production Example 7 was used instead of the hard coating composition of Production Example 1.

[0073] Comparative Example 1: Manufacturing of Hard Coating Film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Comparative Manufacturing Example 1 was used instead of the hard coating composition of Manufacturing Example 1.

[0074] Comparative Example 2: Manufacturing of Hard Coating Film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Comparative Manufacturing Example 2 was used instead of the hard coating composition of Manufacturing Example 1.

[0075] Comparative Example 3: Manufacturing of Hard Coating Film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Comparative Manufacturing Example 3 was used instead of the hard coating composition of Manufacturing Example 1.

[0076] Comparative Example 4: Manufacturing of Hard Coating Film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Comparative Manufacturing Example 4 was used instead of the hard coating composition of Manufacturing Example 1.

[0077] Comparative Example 5: Manufacturing of Hard Coating Film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Comparative Manufacturing Example 5 was used instead of the hard coating composition of Manufacturing Example 1.

[0078] Comparative Example 6: Manufacturing of Hard Coating Film A hard coating film was manufactured in the same manner as in Example 1, except that the hard coating composition of Comparative Manufacturing Example 6 was used instead of the hard coating composition of Manufacturing Example 1.

[0079] Experimental Example 1: The physical properties of the films produced in the above examples and comparative examples were measured using the method described below, and the results are shown in Table 3 below.

[0080] (1) Surface fluorine (F) content The surface fluorine (F) content was measured using Quantera II (Ulvac-PHI) XPS equipment. The sample was prepared in 2cm x 2cm dimensions and then attached to an XPS plate via carbon tape. The measurement surface was positioned upwards. The sample was placed in the intro and a vacuum of 1 x 10⁻⁶ was applied. -4 It was left in Pa for over an hour. After that, it was moved to the main chamber using an arm, and then the vacuum was set to 1 × 10⁻¹⁰. -7 The sample was left in Pa for more than one hour. After maintaining a high vacuum for more than one hour, surface data was obtained by measuring arbitrary positions on the sample surface three times under X-ray conditions (measurement area 200 microns / 25W / 15kV).

[0081] (2) Contact angle The water contact angle was measured using a KRUSS DSA100 contact angle meter. The droplet volume was 3 μl at room temperature.

[0082] (3) Abrasion resistance Measurements were performed using abrasion resistance testing equipment manufactured by DAESUNG PRECISION. The water contact angle was measured after rubbing the coated surface 3000 times with an abrasion resistance test eraser and weight under a load of 1 kg.

[0083] (4) Scratch resistance The base film is bonded to the glass via a transparent adhesive with its coated side facing upwards, and then coated with 500 g / cm² of steel wool (#0000). 2 After subjecting the object to a load and subjecting it to 10 reciprocating friction cycles, light from a three-wavelength lamp was transmitted to and reflected from the measurement area to observe the scratches. Scratch resistance was evaluated according to the following evaluation criteria.

[0084] <Evaluation Criteria> ○: No scratches are visible, or 10 or fewer scratches are visible. ×: More than 10 scratches are visible. (5) Adhesion After the base film was attached to the glass via a transparent adhesive with its coated surface facing upwards, 100 squares were scratched onto the coated surface using a cutter at 1mm intervals, and then three adhesion tests were performed using Nichiban tape. The evaluation results were expressed as "Number of rectangles that passed the adhesion test / 100".

[0085] (6) Flexibility A test was conducted in which the film was repeatedly folded 200,000 times with a radius of curvature of 1 mm, with the hard coating layer facing inward. The presence or absence of film breakage and delamination of the hard coating layer was observed. The bending resistance was evaluated according to the following evaluation criteria. <Evaluation Criteria> ○: No film breakage or hard coating layer delamination occurred. ×: Film breakage or hard coating layer delamination occurs.

[0086] [Table 3]

[0087] As shown in Table 3 above, the hard coating layer according to the present invention is formed from a hard coating composition containing a hydroxyl group-containing translucent resin and a fluorine-based UV-curable functional group-containing compound, and the hard coating films of Examples 1 to 7, in which the atomic percentage of fluorine (F) on the surface of the hard coating layer is 10 to 55 at%, were confirmed to have excellent antifouling properties (contact angle), as well as excellent abrasion resistance, scratch resistance, and bending resistance.

[0088] In contrast, the hard coating films of Comparative Examples 1 to 6, which were formed from hard coating compositions that did not contain one or more of the hydroxyl group-containing translucent resins and fluorine-based UV-curable functional group-containing compounds, or in which the atomic percentage of fluorine (F) on the surface of the hard coating layer exceeded the range of 10 to 55 at%, showed results in which antifouling, abrasion resistance, and scratch resistance could not be ensured.

[0089] Specifically, the hard coating films of Comparative Examples 1, 2, and 6, in which the atomic percentage of fluorine (F) on the surface of the hard coating layer was less than 10 at%, exhibited poor stain resistance and abrasion resistance, while Comparative Example 4, with an atomic percentage exceeding 55 at%, showed reduced scratch resistance. In particular, the hard coating film of Comparative Example 2, which contained an appropriate amount of fluorine-based UV-curable functional group-containing compound but did not contain a hydroxyl group-containing translucent resin, showed a decrease in the atomic percentage of fluorine (F) on the surface of the hard coating layer to less than 10 at%. Furthermore, the hard coating films of Comparative Examples 3 and 5, which used a silicon-based UV-curable functional group-containing compound instead of a fluorine-based UV-curable functional group-containing compound, were found to have poor stain resistance, abrasion resistance, and / or scratch resistance.

[0090] Although specific parts of the present invention have been described in detail above, it is clear to any person with ordinary skill in the art to which the present invention belongs that such specific descriptions are merely preferred examples and do not limit the scope of the present invention. A person with ordinary skill in the art to which the present invention belongs will be able to make various applications and modifications within the scope of the present invention based on the above content.

[0091] Therefore, the substantial scope of the present invention can be defined by the claims and their equivalents.

Claims

1. Substrate, and A hard coating film comprising a hard coating layer formed on at least one surface of the substrate, The hard coating layer is formed from a hard coating composition comprising a hydroxyl group-containing translucent resin, a fluorine-based UV-curable functional group-containing compound, a photoinitiator, and a solvent. When the surface of the hard coating layer was measured by X-ray photoelectron spectroscopy (XPS), the atomic percentage of fluorine (F) on the surface of the hard coating layer was 10 to 55 at%, The hydroxyl group-containing translucent resin is included in an amount of 1 to 50% by weight relative to 100% by weight of the total hard coating composition. The aforementioned fluorine-based UV-curable functional group-containing compound is included in an amount of 10 to 40% by weight relative to 100% by weight of the total hard coating composition. A hard coating film for a flexible display device, wherein the thickness of the hard coating layer is 2 to 5 μm.

2. The hard coating film for a flexible display device according to claim 1, wherein the hydroxyl group-containing translucent resin comprises a hydroxyl group-containing (meth)acrylate compound.

3. The fluorine-based UV-curable functional group-containing compound comprises one or more selected from the group consisting of (meth)acrylate containing a perfluoroalkyl group, (meth)acrylate containing a perfluoropolyether group, (meth)acrylate containing a perfluorocyclic aliphatic group, and (meth)acrylate containing a perfluoroaromatic group, as described in claim 1, for a hard coating film for a flexible display device.

4. The hard coating layer has a water contact angle of 100° or more after being rubbed 3000 times with an eraser and a weight under a load of 1 kg, as described in claim 1.

5. An image display device comprising a hard coating film for a flexible display device according to any one of claims 1 to 4.

6. A window for a flexible display device, comprising a hard coating film for flexible display devices according to any one of claims 1 to 4.

7. A polarizing plate comprising a hard coating film for a flexible display device according to any one of claims 1 to 4.

8. A touch sensor comprising a hard coating film for a flexible display device according to any one of claims 1 to 4.

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