Hard coat film and image display device having the same

Abstract

A hard coat film includes: a substrate; and a hard coat layer formed on at least one surface of the substrate, wherein the hard coat layer is formed from a hard coat layer composition including a hydroxyl group-containing light-transmissive resin, a fluorine-based compound containing a UV-curable functional group, a photoinitiator, and a solvent, and when a surface of the hard coat layer is measured by X-ray photoelectron spectroscopy (XPS), the atomic percentage of elemental fluorine (F) on the surface of the hard coat layer is 10 to 55 atomic %. The hard coat film controls the atomic percentage of elemental fluorine (F) on the surface of the hard coat layer to a specific range using a hard coat layer composition including a hydroxyl group-containing light-transmissive resin and a fluorine-based compound containing a UV-curable functional group, thereby providing excellent stain resistance as well as good abrasion resistance, scratch resistance, and bending resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to a hard coat film and an image display device having the same. In particular, the present application provides a hard coat film having excellent stain resistance, abrasion resistance, scratch resistance, and bending resistance, and an image display device having the same. BACKGROUND

[0002] Hard coat films have been used to protect the surface of various image display devices, including liquid crystal display devices (LCDs), electroluminescent (EL) displays, plasma displays (PDs), field emission displays (FEDs), and the like.

[0003] Such a hard coat film should have high hardness and good scratch resistance, and should not be curled at its end portion during its production or use. Recently, flexible displays or foldable displays are attracting attention as next-generation display devices because they apply a flexible material such as plastic or ultra-thin glass (UTG) instead of a glass substrate that is not flexible, thereby maintaining display performance even if it is bent like paper. Therefore, the hard coat film also needs to have appropriate bending resistance to be applicable to the flexible displays or foldable displays, thereby preventing cracks from being generated.

[0004] Since the hard coat film is generally used by being disposed at the outermost portion of the display, mechanical properties such as abrasion resistance and scratch resistance, and stain resistance and / or easy removability related to traces of fingerprints, markers, and the like are also required as main properties.

[0005] Korean Patent Application Publication No. 10-2005-0010064 discloses an object having a composite hard coat layer and a method of forming the same. The object specifically includes a hard coat layer disposed on the surface of the object and a stain-resistant surface layer disposed on the surface of the hard coat layer. The hard coat layer is a cured product of a hard coat composition containing a living energy ray-curable compound, and the stain-resistant surface layer is a cured product of a surface material containing a fluorine-containing multifunctional (meth)acrylate compound and a fluorine-containing monofunctional (meth)acrylate compound, the stain-resistant surface layer being adhered to the hard coat layer.

[0006] However, in the case of the above-described technology, since the hard coat layer and the stain-resistant layer must be separately introduced on the polymer-based film, the process is complicated, and there is a problem of price increase due to a decrease in yield and an increase in process cost.

[0007] In addition, as the demand for ultra-thin displays increases, there is a need to develop a hard coat film having a hard coat layer as a single layer, which is capable of simultaneously exhibiting stain resistance, and abrasion resistance and scratch resistance. SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] An object of the present application is to provide a hard coat film having excellent stain resistance and good abrasion resistance, scratch resistance, and bending resistance.

[0010] Another object of the present application is to provide an image display device having a hard coat film.

[0011]

Technical Solution

[0012] According to one aspect of the present application, there is provided a hard coat film, comprising:

[0013] a substrate; and

[0014] a hard coat layer formed on at least one surface of the substrate,

[0015] wherein the hard coat layer is formed from a hard coat layer composition comprising a hydroxyl group-containing light-transmissive resin, a fluorine-based UV-curable functional group-containing compound, a photoinitiator, and a solvent, and

[0016] When a surface of the hard coat layer is measured by X-ray photoelectron spectroscopy (XPS), the atomic percentage of element fluorine (F) on the surface of the hard coat layer is 10 to 55 atomic %.

[0017] In one embodiment of the present application, the hydroxyl group-containing light-transmissive resin can include a hydroxyl group-containing (meth)acrylate compound.

[0018] In one embodiment of the present application, the content of the hydroxyl group-containing light-transmissive resin can be 1 to 50% by weight, based on 100% by weight of the total hard coat layer composition.

[0019] In one embodiment of the present application, the fluorine-based UV-curable functional group-containing compound can include one or more selected from the group consisting of a (meth)acrylate containing a perfluoroalkyl group, a (meth)acrylate containing a perfluoropolyether group, a (meth)acrylate containing a perfluorocycloaliphatic group, and a (meth)acrylate containing a perfluoroaromatic group.

[0020] In one embodiment of the present application, the content of the fluorine-based UV-curable functional group-containing compound can be 1 to 40% by weight, based on 100% by weight of the total hard coat layer composition.

[0021] In one embodiment of the present application, the water contact angle of the hard coat layer can be 100° or more after rubbing with an eraser 3000 times under a load of 1 kg weight.

[0022] According to another aspect of the present application, there is provided an image display device having the above hard coat film.

[0023] According to still another aspect of the present application, there is provided a window of a flexible display device having the hard coat film described above.

[0024] According to still another aspect of the present application, there is provided a polarizing plate having the hard coat film described above.

[0025] According to still another aspect of the present application, there is provided a touch sensor having the hard coat film described above.

[0026]

Advantageous Effects

[0027] The hard coat film of the present application controls the atomic percentage of elemental fluorine (F) on the surface of the hard coat layer to a specific range using a hard coat layer composition including a hydroxyl group-containing light-transmissive resin and a fluorine-based UV-curing functional group-containing compound, thereby providing excellent stain resistance as well as good abrasion resistance and scratch resistance. The hard coat film according to the embodiment of the present application has excellent bending resistance, and thus it can be effectively used in a flexible display device or a foldable display device. DETAILED DESCRIPTION

[0028] The present application is described in more detail hereinafter.

[0029] One embodiment of the present application relates to a hard coat film including a substrate and a hard coat layer formed on at least one surface of the substrate,

[0030] wherein the hard coat layer is formed of a hard coat layer composition including a hydroxyl group-containing light-transmissive resin, a fluorine-based UV-curing functional group-containing compound, a photoinitiator, and a solvent, and

[0031] When the surface of the hard coat layer is measured by X-ray photoelectron spectroscopy (XPS), the atomic percentage of elemental fluorine (F) on the surface of the hard coat layer is 10-55 atomic %.

[0032] The hard coat film according to one embodiment of the present application forms a hard coat layer using a hard coat layer composition including a hydroxyl group-containing light-transmissive resin and a fluorine-based UV-curing functional group-containing compound, thereby providing stain resistance as well as good abrasion resistance. Specifically, the hydroxyl group of the hydroxyl group-containing light-transmissive resin repels the fluorine atom of the fluorine-based UV-curing functional group-containing compound, so that the fluorine atom is oriented toward the surface of the hard coat layer, which controls the atomic percentage of elemental fluorine (F) on the surface of the hard coat layer to a level of 10-55 atomic %. Thus, not only stain resistance but also abrasion resistance and scratch resistance can be exhibited. In particular, the hydroxyl group-containing light-transmissive resin can improve the abrasion resistance of the hard coat layer by forming a matrix of the hard coat layer through photocuring.

[0033] Accordingly, the hard coat film according to one embodiment of the present application can have a hard coat layer capable of simultaneously exhibiting stain resistance as well as abrasion resistance and scratch resistance as a single layer, which can be advantageously applied to an ultra-thin display.

[0034] In addition, the hard coat film according to one embodiment of the present application has excellent resistance to bending, and thus even if the film is repeatedly folded and unfolded 200,000 times with a radius of curvature of 1 mm with the hard coat layer folded inward, film breakage or hard coat layer peeling does not occur, which can be advantageously applied to flexible displays or foldable displays.

[0035] In the hard coat film according to one embodiment of the present application, the atomic percentage of the element fluorine (F) on the surface of the hard coat layer is 10 to 55 atomic %, preferably 15 to 55 atomic %, and more preferably 15 to 50 atomic % when measured on the surface of the hard coat layer by X-ray photoelectron spectroscopy (XPS). If the atomic percentage of the element fluorine (F) on the surface of the hard coat layer is less than 10 atomic %, the stain resistance and the abrasion resistance can be deteriorated, and if it exceeds 55 atomic %, the scratch resistance can be deteriorated.

[0036] The atomic percentage of the element fluorine (F) on the surface of the hard coat layer is a value measured on the surface of the hard coat layer by X-ray photoelectron spectroscopy (XPS) according to the method described in Experimental Example, which will be described later.

[0037] The hard coat film according to one embodiment of the present application includes a substrate and a hard coat layer formed on at least one surface of the substrate.

[0038] In one embodiment of the present application, the substrate is not limited as long as it is a substrate used in the art, and specifically, a film having good transparency, mechanical strength, thermal stability, moisture resistance, isotropy, and the like can be used. Specific examples of the substrate can include a film made of a thermoplastic resin, such as a polyester resin, for example, polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; a cellulose resin, for example, diacetyl cellulose and triacetyl cellulose; a polycarbonate resin; an acrylate resin, for example, poly(methyl) methyl acrylate and poly(methyl) ethyl acrylate; a styrene resin, for example, polystyrene and acrylonitrile-styrene copolymer; a polyolefin resin, for example, polyethylene, polypropylene, a polyolefin having a cyclic or norbornene structure, and ethylene-propylene copolymer; a vinyl chloride resin; an amide resin, for example, nylon and aromatic polyamide; an imide resin; a sulfone resin; a polyether sulfone resin; a polyether ether ketone resin; a polyphenylene sulfide resin; a vinyl alcohol resin; a vinylidene chloride resin; a vinyl butyral resin; an allyl resin; a polyformaldehyde resin; and an epoxy resin. In addition, a film composed of a blend of thermoplastic resins can be used. Furthermore, a film made of an ultraviolet-curable resin or a thermosetting resin such as (meth)acryl urethane, acryl urethane, an epoxy resin, or silicone or UTG (ultra-thin glass) can be used. According to one embodiment of the present application, a polyimide-based resin or a polyester-based resin having excellent durability against repeated bending can be used to be easily applied to a flexible display device.

[0039] The thickness of the substrate is not particularly limited, but can be 8 to 1000 μm, and specifically, 20 to 150 μm. If the thickness of the substrate is less than 8 μm, the strength of the film is reduced, so that the processability is deteriorated, and when it exceeds 1000 μm, there is a problem that the transparency is reduced or the weight of the hard coat film is increased.

[0040] In one embodiment of the present application, the hard coat layer can be formed by applying a hard coat layer composition on at least one surface of the substrate.

[0041] Since the hard coat layer exhibits stain resistance, it can be difficult to attach to an optical layer or a panel disposed thereunder when it is formed on the opposite surface of the viewing side of the substrate. Therefore, the hard coat layer can be preferably formed as a single layer on the viewing side of the substrate.

[0042] In one embodiment of the present application, the hard coat layer composition comprises a hydroxyl group-containing light-transmissive resin, a fluorine-based compound containing a UV-curable functional group, a photoinitiator, and a solvent.

[0043] In one embodiment of the present application, the hydroxyl group-containing light-transmissive resin is a photocurable resin, and the photocurable resin can include a hydroxyl group-containing (meth)acrylate compound.

[0044] Examples of the hydroxyl group-containing (meth)acrylate compound can include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 1,4-butanediol mono(meth)acrylate, 2-hydroxyalkyl (meth)acryloyl phosphate (in this context, the alkyl group is, for example, methyl, ethyl, or propyl), 4-hydroxycyclohexyl (meth)acrylate, 1,6-hexanediol mono(meth)acrylate, neopentyl glycol mono(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolethane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and the like. These can be used alone or in combination of two or more.

[0045] The content of the hydroxyl group-containing light-transmitting resin can be 1 to 50% by weight, preferably 5 to 50% by weight, based on 100% by weight of the total hard coat composition. If the content of the hydroxyl group-containing light-transmitting resin is less than 1% by weight, the abrasion resistance can be deteriorated, and it can be difficult to achieve sufficient improvement in hardness. If it exceeds 50% by weight, the curling problem can become serious.

[0046] In one embodiment of the present application, the fluorine-based compound containing a UV-curable functional group is a component that imparts stain resistance, abrasion resistance, and chemical resistance. The fluorine-based compound containing a UV-curable functional group is not particularly limited as long as it contains fluorine and a UV-curable functional group so as to chemically bond with the hydroxyl group-containing light-transmitting resin of the matrix forming the hard coat.

[0047] As the fluorine-based compound containing a UV-curable functional group, one or more selected from the group consisting of a (meth)acrylate containing a perfluoroalkyl group, a (meth)acrylate containing a perfluoropolyether group, a (meth)acrylate containing a perfluorocycloaliphatic group, and a (meth)acrylate containing a perfluoroaromatic group can be used. In this case, it exhibits excellent stain resistance while having the advantage of excellent durability by chemically bonding with the hard coat to maintain the stain resistance for a long time even after repeated use.

[0048] The fluorine-based compound containing a UV-curable functional group preferably has 1 to 6 UV-curable functional groups.

[0049] The content of the fluorine-based UV-curable functional group-containing compound can be 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 coat composition. If the content of the fluorine-based UV-curable functional group-containing compound is within the above range, excellent abrasion resistance and stain resistance can be preferably imparted. When the content of the UV-curable functional group-containing compound is less than the above range, it can be difficult to sufficiently improve the abrasion resistance or the stain resistance, and when it exceeds the above range, the hardness and / or the scratch resistance can be reduced.

[0050] In one embodiment of the present application, a photoinitiator is included to induce photocuring of the hard coat composition, and it can include, for example, a photoradical initiator capable of forming radicals by irradiation with light.

[0051] Examples of the photoinitiator can include a Type I initiator in which radicals are generated by molecular decomposition due to differences in chemical structure or molecular binding energy, a Type II initiator in which a tertiary amine is introduced as a co-initiator to induce hydrogen abstraction, and the like.

[0052] For example, the Type I initiator can include acetophenone-based compounds such as 4-phenoxydichloroacetophenone, 4-tert-butyl-dichloroacetophenone, 4-tert-butyltrichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, and the like; benzoin-based compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzyl dimethyl ketal; phosphine oxide; and titanocene compounds.

[0053] For example, the Type II initiator can include benzophenone-based compounds such as benzophenone, benzoylbenzoic acid, benzoylbenzoic acid methyl ether, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl diphenyl sulfide, 3,3'-methyl-4-methoxybenzophenone, and the like; or thioxanthone-based compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, and the like.

[0054] These photoinitiators can be used alone or in combination of two or more. In addition, the Type I initiator and the Type II initiator can be used alone or together.

[0055] The content of the photoinitiator can be 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on 100% by weight of the total hard coat composition. If the amount of the photoinitiator is less than 0.1% by weight, curing cannot be sufficiently performed, and thus it can be difficult to achieve mechanical properties and adhesive strength of the hard coat film or hard coat layer. If the amount of the photoinitiator exceeds 10% by weight, cracks, curling, and adhesive failure due to curing shrinkage can occur.

[0056] In one embodiment of the present application, the solvent can be, but is not limited to, any one of the solvents known in the art capable of dissolving or dispersing the above composition. In addition, the solvent serves to provide time for the fluorine-based compound containing a UV-curable functional group to float to the outermost surface of the coating layer due to the difference in surface tension during the process of applying the hard coat composition to the substrate and drying it.

[0057] Examples of the solvent can include 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, t-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, methoxyamyl acetate, etc.), hexanes (hexane, heptane, octane, etc.), benzenes (benzene, toluene, xylene, etc.), ethers (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, etc.). These solvents can be used alone or in combination of two or more.

[0058] The content of the solvent can be 10 to 50% by weight, preferably 20 to 50% by weight, based on 100% by weight of the total hard coat composition. If the content of the solvent is less than the above range, not only the processability is deteriorated due to high viscosity, but also the swelling of the substrate cannot be sufficiently performed. On the contrary, when it exceeds the above range, the drying process takes a large amount of time, and the economic efficiency is low. Therefore, the solvent can be appropriately used within the above range.

[0059] In one embodiment of the present application, the hard coat composition can further include another light-transmissive resin in addition to the light-transmissive resin containing a hydroxyl group.

[0060] The other light-transmissive resin can include a photocurable (meth)acrylate oligomer and / or monomer.

[0061] As the photocurable (meth)acrylate oligomer, an epoxy (meth)acrylate, a urethane (meth)acrylate, or the like is generally used, and a urethane (meth)acrylate is preferred. The urethane (meth)acrylate can be prepared by reacting a (meth)acrylate having a hydroxyl group in the molecule with a compound having an isocyanate group in the presence of a catalyst. Specific examples of the (meth)acrylate having a hydroxyl group in the molecule can include 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone ring-opening hydroxy acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like. In addition, specific examples of the compound having an isocyanate group can include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, 1,5-diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis(isocyanatomethyl)cyclohexane, trans-1,4-cyclohexene diisocyanate, 4,4'-methylenebis(isocyanatocyclohexane), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethyl xylene-1,3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenyl isocyanate), 4,4'-oxybis(isocyanatophenyl), a trifunctional isocyanate derived from hexamethylene diisocyanate, and trimethylolpropane-toluene diisocyanate adduct, and the like.

[0062] The monomer is not limited as long as it is generally used in the art. It is preferred that the monomer has an unsaturated group such as a (meth)acryloyl group, a vinyl group, a styryl group, an allyl group, or the like as a photocurable functional group in the molecule, and a monomer having a (meth)acryloyl group is preferred.

[0063] Specific examples of the monomer having a (meth)acryloyl group can include 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, trimethyloloethane tri(meth)acrylate, 1,2,4-cyclohexane tetra(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, isobornyl (meth)acrylate, and the like.

[0064] The above exemplified photocurable (meth)acrylate oligomers and monomers can be used alone or in combination of two or more thereof.

[0065] The amount of the other light-transmitting resin is not particularly limited based on 100% by weight of the total hard coat composition, but the content thereof can be equal to or less than 50% by weight, for example, 1 to 50% by weight. When the content of the other light-transmitting resin exceeds 50% by weight, it can be difficult to control the atomic percentage of the element fluorine (F) on the surface of the hard coat layer to a level of 10 to 55%, or a serious curling problem can occur.

[0066] If desired, the hard coat composition can further include other components conventionally used in the art, such as a leveling agent, a UV stabilizer, a heat stabilizer, an antioxidant, a surfactant, a lubricant, a stain preventing agent, and the like.

[0067] The hard coat layer can be formed by applying the hard coat composition on one or both surfaces of the substrate, and then drying and UV-curing.

[0068] The hard coat composition can be applied on the substrate by appropriately using a known coating method such as a die coater, an air knife, a reverse roll, a spray, a doctor blade, a casting, a gravure printing, a microgravure printing, a spin coating, and the like.

[0069] After the hard coat composition is applied on the substrate, a drying process can be performed at a temperature of 30 to 150°C by evaporating the volatile matter for 10 seconds to 1 hour, more specifically, 30 seconds to 30 minutes, and then UV-curing is performed. The amount of irradiation of UV light can be specifically about 0.01 to 10 J / cm 2 , more specifically, 0.1 to 2 J / cm 2 .

[0070] At this time, the thickness of the hard coat layer to be formed can be specifically 2 to 30 μm, more specifically, 3 to 20 μm, preferably, 2 to 8 μm, more preferably, 2 to 7 μm. When the thickness of the hard coat layer is included in the above range, excellent hardness and bending resistance can be obtained.

[0071] One embodiment of the present application relates to an image display device having the above hard coat film. For example, the hard coat film of the present application can be used as a window of an image display device, particularly a flexible display device or a foldable display device. In addition, the hard coat film of the present application can be used by being attached to a polarizing plate or a touch sensor, particularly a polarizing plate or a touch sensor for a flexible display device or a foldable display device.

[0072] The hard coat film according to one embodiment of the present application can be used for a reflective, transmissive, and transflective liquid crystal device (LCD); or an LCD of various operation modes, including a twisted nematic (TN), a super twisted nematic (STN), an optically compensated birefringence (OCB), a hybrid aligned nematic (HAN), a vertical alignment (VA), and an in-plane switching (IPS). In addition, the hard coat film according to one embodiment of the present application can be used for various image display devices including a plasma display, a field emission display, an organic EL display, an inorganic EL display, electronic paper, and the like.

[0073] Hereinafter, the present application will be described in more detail with reference to Examples, Comparative Examples, and Experimental Examples. It will be obvious to those skilled in the art that these Examples, Comparative Examples, and Experimental Examples are for illustrative purposes only and are not intended to limit the scope of the present application.

[0074] Preparation Examples and Comparative Preparation Examples: Preparation of Hard Coat Composition

[0075] Each component of the composition of Tables 1 and 2 below was mixed using a stirrer, and then filtered with a polypropylene (PP) filter to prepare a hard coat composition (wt%).

[0076] Table 1

[0077]

[0078]

[0079] Table 2

[0080]

[0081] A-1: 3-functional acrylate (Miramer M340 from Miwon Specialty Chemical)

[0082] A-2: 5-functional acrylate (SR399LV NS from Sartomer)

[0083] B-1: 6-functional urethane acrylate (UA-110H from Shin-Nakamura Chemical)

[0084] B-2: 6-functional acrylate (DPHA NS from Sartomer)

[0085] B-3: 6-functional acrylate (UA-1100H from Shin-Nakamura Chemical)

[0086] C-1: Fluorine-based compound containing UV-curable functional group (KY-1203 from Shin-Etsu Chemical, 80 wt% MEK (methyl ethyl ketone) dilution, solid content 20 wt%)

[0087] C-2: Fluorine-based compound containing UV-curable functional group (DAC-HP from Daikin, 80 wt% mixed solvent of fluorine-based solvent (1,1,2,2,3,4-heptafluorocyclopentane) and solvent (1-methoxy-2-propanol) (50 wt% and 30 wt% respectively) dilution, solid content 20 wt%)

[0088] C-3: Fluorine-based compound containing UV-curable functional group (FS-7026 from Fluoro Technology)

[0089] C-4: Silicone-based compound containing UV-curable functional group (BYK UV3570 from BYK Chemie)

[0090] D-1: 1-hydroxycyclohexyl phenyl ketone

[0091] E-1: Methyl ethyl ketone

[0092] Example 1: Preparation of hard coat film

[0093] The hard coat composition prepared in Preparation Example 1 was coated on a polyester film (PET, 50 μm) so as to have a thickness of 5 μm after curing, the solvent was dried, and the composition was cured by irradiation with UV light of an integrated amount (600 mJ / cm2) to produce a hard coat film. 2 ) of UV light to produce a hard coat film.

[0094] Example 2: Preparation of hard coat film

[0095] A hard coat film was prepared in the same manner as in Example 1, except that the hard coat composition of Preparation Example 2 was used instead of the hard coat composition of Preparation Example 1.

[0096] Example 3: Preparation of hard coat film

[0097] A hard coat film was prepared in the same manner as in Example 1, except that the hard coat composition of Preparation Example 3 was used instead of the hard coat composition of Preparation Example 1.

[0098] Example 4: Preparation of hard coat film

[0099] A hard coat film was prepared in the same manner as in Example 1, except that the hard coat composition of Preparation Example 4 was used instead of the hard coat composition of Preparation Example 1.

[0100] Example 5: Preparation of hard coat film

[0101] A hard coat film was produced in the same manner as in Example 1, except that the hard coat composition of Production Example 5 was used instead of the hard coat composition of Production Example 1.

[0102] Example 6: Production of a Hard Coat Film

[0103] A hard coat film was produced in the same manner as in Example 1, except that the hard coat composition of Production Example 6 was used instead of the hard coat composition of Production Example 1.

[0104] Example 7: Production of a Hard Coat Film

[0105] A hard coat film was produced in the same manner as in Example 1, except that the hard coat composition of Production Example 7 was used instead of the hard coat composition of Production Example 1.

[0106] Comparative Example 1: Production of a Hard Coat Film

[0107] A hard coat film was produced in the same manner as in Example 1, except that the hard coat composition of Comparative Production Example 1 was used instead of the hard coat composition of Production Example 1.

[0108] Comparative Example 2: Production of a Hard Coat Film

[0109] A hard coat film was produced in the same manner as in Example 1, except that the hard coat composition of Comparative Production Example 2 was used instead of the hard coat composition of Production Example 1.

[0110] Comparative Example 3: Production of a Hard Coat Film

[0111] A hard coat film was produced in the same manner as in Example 1, except that the hard coat composition of Comparative Production Example 3 was used instead of the hard coat composition of Production Example 1.

[0112] Comparative Example 4: Production of a Hard Coat Film

[0113] A hard coat film was produced in the same manner as in Example 1, except that the hard coat composition of Comparative Production Example 4 was used instead of the hard coat composition of Production Example 1.

[0114] Comparative Example 5: Production of a Hard Coat Film

[0115] A hard coat film was produced in the same manner as in Example 1, except that the hard coat composition of Comparative Production Example 5 was used instead of the hard coat composition of Production Example 1.

[0116] Comparative Example 6: Production of a Hard Coat Film

[0117] A hard coat film was produced in the same manner as in Example 1, except that the hard coat composition of Comparative Production Example 6 was used instead of the hard coat composition of Production Example 1.

[0118] Experimental Example 1:

[0119] The physical properties of the films prepared in the examples and comparative examples were measured by the following methods, and the results are shown in Table 3 below.

[0120] (1) Surface elemental fluorine (F) content

[0121] The surface elemental fluorine (F) content was measured using a Quantera II (Ulvac-PHI) XPS instrument. After preparing a sample of 2 cm x 2 cm, it was attached to an XPS dedicated plate with a carbon tape. At this time, the measurement surface was made to face upward. The sample was placed in the Intro and kept for 1 hour or more under a vacuum degree of 1 x 10 -4 Pa. After that, it was moved to the main chamber using an arm, and then kept for 1 hour or more under a vacuum degree of 1 x 10 -7 Pa. After keeping under high vacuum for 1 hour or more, 3 measurements were made on an arbitrary position of the surface of the sample under X-ray conditions (measurement area 200 micrometers / 25 W / 15 kV), and surface data was obtained.

[0122] (2) Contact angle

[0123] The water contact angle was measured using a contact angle meter DSA100 from KRUSS. The volume of the droplet was 3 μl at room temperature.

[0124] (3) Abrasion resistance

[0125] The abrasion resistance was measured using an abrasion resistance meter from Daesung Precision Machine. After rubbing the coating surface with an abrasion eraser under a load of 1 kg for 3000 times, the water contact angle was measured.

[0126] (4) Scratch resistance

[0127] The substrate film was attached to glass using a transparent adhesive so that the coating surface faced upward, and reciprocating rubbing was performed 10 times using steel wool (#0000) under a load of 500 g / cm 2 , and then scratches were observed by transmitting and reflecting the measurement part using a three-wavelength lamp. The scratch resistance was evaluated according to the following evaluation criteria.

[0128] <Evaluation Criteria>

[0129] O: Scratches were not visible, or 10 or less scratches were visible

[0130] X: More than 10 scratches were visible

[0131] (5) Adhesion

[0132] The substrate film was attached to the glass using a transparent adhesive so that the coating surface faced upward, a cutting knife was used to form a 100-square grid on the coating surface at 1 mm intervals, and 3 adhesion tests were performed using Nichiban tape.

[0133] The evaluation results are expressed as "number of squares OK after the adhesion test / 100."

[0134] (6) Flexibility

[0135] The film was repeatedly folded and unfolded 200,000 times with a radius of curvature of 1 mm so that the hard coating was folded inward, and whether the film was broken and the hard coating was peeled off was observed. The flexibility was evaluated according to the following evaluation criteria.

[0136] <evaluation criteria>

[0137] O: No film breakage and hard coating peeling occurred

[0138] X: Film breakage or hard coating peeling occurred

[0139] Table 3

[0140] Surface elemental fluorine (F) content Contact angle Wear resistance Scratch resistance Adhesion Bending resistance Example 1 35 109 100 ○ 100 / 100 ○ Example 2 20.27 110 101 ○ 100 / 100 ○ Example 3 30.11 111 102 ○ 100 / 100 ○ Example 4 20.27 109 100 ○ 100 / 100 ○ Example 5 41.2 113 104 ○ 100 / 100 ○ Example 6 25.12 110 103 ○ 100 / 100 ○ Example 7 48.7 117 105 ○ 100 / 100 ○ Comparative Example 1 5.9 106 89 ○ 100 / 100 ○ Comparative Example 2 7 107 93 × 100 / 100 ○ Comparative Example 3 0 97 65 ○ 100 / 100 ○ Comparative Example 4 60 111 85 × 100 / 100 ○ Comparative Example 5 0 98 61 × 100 / 100 ○ Comparative Example 6 9 108 92 × 100 / 100 ○

[0141] As shown in Table 3 above, the hard coat films according to Examples 1 to 7 of the present application, in which the hard coating layer was formed from a hard coat composition including at least one of a light-transmitting resin containing a hydroxyl group and a fluorine-based compound containing a UV-curable functional group, and the atomic percentage of elemental fluorine (F) on the surface of the hard coating layer was 10 to 55 atomic %, confirmed that the hard coat films had excellent stain resistance (contact angle) and excellent abrasion resistance, scratch resistance, and flexibility.

[0142] On the other hand, the hard coat films of Comparative Examples 1 to 6, in which the hard coating layer was formed from a hard coat composition not including at least one of a light-transmitting resin containing a hydroxyl group and a fluorine-based UV-curable functional group, or had an atomic percentage of elemental fluorine (F) on the surface of the hard coating layer outside the range of 10 to 55 atomic %, could not simultaneously achieve stain resistance, abrasion resistance, and scratch resistance.

[0143] Specifically, the hard coat films of Comparative Examples 1, 2 and 6, in which the atomic percentage of elemental fluorine (F) on the surface of the hard coat layer is less than 10 atomic %, have poor stain resistance and abrasion resistance, while Comparative Example 4, which exceeds 55 atomic %, has poor scratch resistance. In particular, in the hard coat film of Comparative Example 2, which does not contain a light-transmitting resin containing a hydroxyl group, the atomic percentage of elemental fluorine (F) on the surface of the hard coat layer is less than 10 atomic %, even though it contains an appropriate amount of a fluorine-based compound containing a UV-curable functional group. Furthermore, the hard coat films of Comparative Examples 3 and 5, which use a compound containing a UV-curable functional group based on silicone instead of a fluorine-based compound containing a UV-curable functional group, have poor stain resistance, abrasion resistance and / or scratch resistance.

[0144] While particular embodiments of the present application have been shown and described in detail, it will be understood by those skilled in the art that the application can be implemented differently without departing from the spirit and scope of the present application, and that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the present application.

[0145] Therefore, the true scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A hard coating film, comprising: substrate; and A hard coating layer is formed on at least one surface of the substrate. The hard coating is formed from a hard coating composition comprising: a hydroxyl-containing transparent resin, a fluorinated compound containing UV-curable functional groups, a photoinitiator, and a solvent. When the surface of the hard coating is measured by X-ray photoelectron spectroscopy (XPS), the atomic percentage of fluorine (F) on the surface of the hard coating is 10–55 atomic%. The hydroxyl-containing light-transmitting resin, in a total hard coating composition of 100% by weight, comprises 1 to 50% by weight. In the total hard coating composition (100% by weight), the content of the fluorine-based UV-curable functional group compound is 10-40% by weight. After 3000 rubs with a scrubber under a 1kg load, the water contact angle of the hard coating is 100° or greater. The thickness of the hard coating is 2 μm to 7 μm.

2. The hard coating film according to claim 1, wherein the hydroxyl-containing light-transmitting resin comprises a hydroxyl-containing (meth)acrylate compound.

3. The hard coating film according to claim 1, wherein the fluorine-based UV-curable functional group compound comprises one or more selected from the group consisting of: (meth)acrylates containing perfluoroalkyl groups, (meth)acrylates containing perfluoropolyether groups, (meth)acrylates containing perfluorocycloaliphatic groups, and (meth)acrylates containing perfluoroaromatic groups.

4. An image display device having a hard coating according to any one of claims 1 to 3.

5. A window of a flexible display device having a hard coating according to any one of claims 1 to 3.

6. A polarizing plate having a hard coating according to any one of claims 1 to 3.

7. A touch sensor having a hard coating according to any one of claims 1 to 3.

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