WO2018143554A1 - Hard coating film and flexible display window comprising touch sensor having same - Google Patents

Abstract

A hard coating film according to the present invention comprises: a substrate; a functional coating layer provided on one surface of the substrate; and an antistatic coating layer provided on the other surface of the substrate and having a surface resistance of 10E+11Ω/□ or lower, wherein the yellow index (YI) is 1.2 or lower.

Description

Flexible display window comprising a hard coating film and a touch sensor having the same

The present invention relates to a hard coating film having excellent YI (yellow index) reduction and antistatic function and an image display device including the same.

Recently, with the development of mobile devices such as smartphones and tablet PCs, thinning and slimming of the display base material are required. Glass or tempered glass is generally used as a material having excellent mechanical properties in the display window or the front plate of the mobile device. However, the glass causes the mobile device to be heavier due to its weight, and there is a problem of breakage due to external impact, and it is difficult to implement a flexible display.

Therefore, plastic resin is being researched as a substitute material for glass. The plastic resin composition is lightweight and less likely to be broken, and above all, it is possible to implement flexible and suitable for the trend toward a lighter mobile device. Particularly, touch driving is possible and dust adhesion can be prevented, as well as base films having characteristics of surface resistance, pencil hardness and flex resistance, and researches have been made, and polyimide films have emerged as alternatives. However, such a polyimide film-based hard coat film also has a problem of having a high YI (yellow index) value.

Typically, the hard coat film comprises a substrate and a hard coat layer. If the YI value is high, image display devices such as LCDs and LEDs with hard coating films do not display the desired color, and there is a problem of degrading the quality. Therefore, it is necessary to increase the amount of backlight light to compensate for the YI value or to adjust the color balance. This can also cause a drop in battery life.

Republic of Korea Patent Publication No. 1998-0020031 relates to an antistatic photocuring hard coating composition and a coating method thereof, in the antistatic hard coating composition of a transparent plastic, 10 to 60% by weight, tri-functional acrylic monomer 4-20% by weight of acrylic monomer, 20-60% by weight of bifunctional acrylmonomer, 3-7% by weight of photoinitiator, 3-40% by weight of antistatic agent for UV curing, 0-10% by weight of conductive titania and small amount of UV stabilizer Disclosed is a content of an antistatic photocuring hard coating agent composition comprising a.

However, the above documents also do not present an alternative for reducing YI. Therefore, there is a demand for the development of a hard coating film capable of preventing static adsorption as well as reducing YI.

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) Republic of Korea Patent Publication No. 1998-0020031 (1998.06.25.)

An object of the present invention to provide a hard coat film capable of antistatic function and YI reduction.

It is also an object of the present invention to provide a window of an image display device or a display device including the hard coat film described above.

Hard coating film of the present invention for achieving the above object is a substrate; A functional coating layer provided on one surface of the substrate; And an antistatic coating layer having a surface resistance of 10E + 11Ω / □ or less provided on the other surface of the substrate, wherein YI (yellow index) is 1.2 or less.

In addition, the present invention provides a window cover film of a flexible display device having the above-described hard coating film.

In addition, the present invention provides an image display device including the window cover film described above.

The hard coating film according to the present invention has an YI value of 1.2 or less, and includes an antistatic coating layer having a surface resistance of 10E + 11Ω / □ or less, and a functional coating layer. It is advantageous in terms of process and has a low YI value.

In addition, the image display device including the hard coat film according to the present invention has a low YI value.

1 to 3 illustrate hard coat films in accordance with some embodiments of the invention.

Hereinafter, the present invention will be described in more detail.

In the present invention, when a member is located "on" another member, this includes not only when one member is in contact with another member but also when another member exists between the two members.

In the present invention, when a part "includes" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.

<Hard Coating Film>

One aspect of the present invention, substrate 10; A functional coating layer 20 provided on one surface of the substrate 10; And an antistatic coating layer 30 having a surface resistance of 10E + 11Ω / □ or less provided on the other surface of the substrate 10, and relates to a hard coating film 100 having a YI (yellow index) of 1.2 or less.

The hard coating film 100 may further include a protective film layer, a pressure-sensitive adhesive layer, an adhesive layer and the like commonly used in the art within a range that does not impair the purpose of the present invention.

In the present invention, the substrate 10 is a transparent substrate, and is not limited as long as it is a transparent polymer film.

In the present invention, the "transparent" means that the visible light transmittance is 80% or more.

For example, the substrate 10 may be a film formed of a polymer such as triacetyl cellulose, acetyl cellulose butyrate, polyamide, polyetherimide, polyacryl, polyimide, polymethyl methacrylate, polyethylene terephthalate, polycarbonate, or the like. However, the present invention is not limited thereto, and the polymer may be used alone or in combination of two or more thereof.

The substrate 10 may be a plasma or corona treatment, but is not limited thereto. However, when the substrate 10 subjected to the plasma or corona treatment is used, the adhesion between the functional coating layer 20 and the antistatic coating layer 30 in contact with the substrate 10 is preferably increased.

In order to use the hard coating film 100 as a window cover film, when the post-treatment such as black matrix or anti-finger treatment is performed, it must be able to withstand high temperature processes and flexible foldable, so it is required to have excellent bending resistance. Most preferably, a mid film is used.

The thickness of the substrate 10 film may be 8 ~ 1000㎛, specifically 40 ~ 100㎛. When the thickness of the film of the base material 10 is within the above range, the film has high strength, and thus, excellent workability may be prevented, and a phenomenon in which transparency is lowered may be prevented, and the hard coating film 100 may be reduced in weight.

Referring to FIG. 1, one surface of the substrate 10 is provided with a functional coating layer 20, and the other surface of the substrate 10, that is, one surface of the substrate 10 that is not provided with the functional coating layer 20. The antistatic coating layer 30 is provided.

The hard coating film 100 has a YI (yellow index) of 1.2 or less, and the antistatic coating layer 30 has a surface resistance of 10E + 11Ω / □ or less.

One embodiment of the present invention, the functional coating layer 20 relates to a hard coat film 100 comprising a cured product of the functional composition containing a color compensator.

Specifically, the functional coating layer 20 is formed using a functional composition, and the method of manufacturing the functional coating layer 20 using the functional composition is not limited in the present invention.

For example, the functional coating layer 20 may form the functional composition through a die coater, air knife, reverse roll, spray, blade, casting, gravure, micro gravure and spin coating.

In another embodiment of the present invention, the color compensating agent may include a blue-based anthraquinone dye. Since the functional coating layer 20 according to the present invention includes a color compensator, specifically a blue-based anthraquinone dye, the YI of the hard coating film 100 including the functional coating layer 20 is 1.2 or less, specifically, 0.9 or less, more specifically 0.7 or less.

When the blue anthraquinone-based dye is included in the functional coating layer 20, the functional coating layer emits blue light as a whole, thereby reducing YI due to the action of reducing yellowness of the entire film.

The blue anthraquinone dye is a dye containing a compound having an anthraquinone skeleton in a molecule.

The blue anthraquinone dyes are, for example, MACROLEXTM Violet B commercially available from 1-hydroxy-4- (p-toluidino) anthraquinone Lanxess And DIARESIN Violet D, DIARESIN Blue G, and DIARESIN commercially available from MACROLEX Blue 3R, SUMIPLAST Violet RR, SUMIPLAST Violet B, SUMIPLAST Blue OR, Mitsubishi Chemical, commercially available from MACROLEX Blue RR, Sumitomo Chemical Co., Ltd. Blue N and the like, but is not limited thereto.

Preferably, the anthraquinone dye is preferably dissolved in an organic solvent, and 1-hydroxy-4- (p-toluidino) anthraquinone is preferably SUMIPLAST Violet B as a commercial item.

In another embodiment of the present invention, the color compensating agent may be included in 100 to 1000 ppm, preferably 200 to 1000 ppm, more preferably 300 to 1000 ppm relative to the total solids of the functional composition.

When the color compensator is included in the above range, it is preferable because it satisfies the flexural resistance and the like, and the YI reduction is maximized. If the color compensator is included in less than the above range may be slightly reduced YI, when the color compensator is exceeded there is a problem in that the excess of the low solubility of the color compensator has to be put in excess, and also such as precipitation or poor coating It is preferable to satisfy the above range as it may occur.

Another embodiment of the present invention relates to a hard coat film 100 wherein the antistatic coating layer 30 comprises a cured product of an antistatic composition comprising a lithium ion compound.

Specifically, the antistatic coating layer 30 is formed using an antistatic composition, and the method of manufacturing the antistatic coating layer 30 using the antistatic composition is not limited in the present invention.

For example, the antistatic coating layer 30 may form the antistatic composition through a die coater, air knife, reverse roll, spray, blade, casting, gravure, micro gravure.

The lithium ion compound may be, for example, lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium hexafluoroalsenate (LiAsF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), and Lithium trifluoromethanesulfonate (LiTf), lithium bistrifluoromethanesulfonimide (LiTFSI), lithium bistrifluoromethanesulfonimide (LiBETI), lithium bifluoro Sulfonylamide (LiFSI), superacid lithium salt system (LiSA: C _n F _{2n + 1} SO ₃ Li, n = 4,8,10), lithium polyanion salt system, 1,2,3-dithiazolidine-4 Lithium-4,5-dicyano-2 as 4,5,5-tetrafluoro-1,1,3,3-tetraoxide (LiCTFSI), lithium bisoxalate borate (LiBOB), imidazole-based lithium salt -Trifluoromethylimidazole (LiTDI), lithium-4,5-dicyano-2-pentafluoroethylimidazole (LiPDI), lithium fluorine-free lithium salt , 5-dicyano-1,2,3-triazolate (LiDCTA), lithium tetracyanoborate (LiB (CN) ₄ ) and the like, but is not limited thereto, and may be used alone or in combination of two or more thereof. Can be.

Although not wishing to be bound by theory, the lithium ion compound combines with oxygen atoms in the translucent resin to be described later to perform a function of improving the electrical conductivity of the hard coat layer 40. In addition, at the same time, rather than covalent bonds in the hard coat layer 40 to form a floating ion bonding site (site) acts as a semi-crosslinking bond when measuring the hardness to improve the hardness and at the same time unlike the covalent bond in the flexural test The effect of freely dissociating bonds and then recombining at other sites is to enhance flexibility, thereby improving both hardness and flexibility.

In short, the antistatic coating layer 30 according to the present invention has the advantage that the surface resistance is 10E + 11Ω / □ or less by including the lithium ion compound. Therefore, there is less foreign matter defects due to static electricity has an excellent advantage in terms of process and cost.

The lithium ion compound may be included in an amount of 2 to 5 parts by weight, preferably 3 to 5 parts by weight, based on 100 parts by weight of the total antistatic composition. In this case, there is an advantage in that antistatic performance and surface coating properties can be simultaneously implemented. . When the lithium ion compound is included in the range below the anti-electricity improvement may be inadequate due to the lack of the electrical conductivity improvement, if it exceeds the above range, the antistatic coating layer is prepared as the content of the light-transmissive resin to be described later is reduced Since the mechanical properties of the 30 may be lowered, it is preferable to be included within the above range.

In another embodiment of the present invention, the functional composition may further include one or more selected from the group consisting of a light transmitting resin, a solvent, an initiator and an additive.

In another embodiment of the present invention, the antistatic composition may further include one or more selected from the group consisting of a light transmitting resin, a solvent, an initiator and an additive.

Translucent resin, solvent, initiator and additives that can be included in the functional composition and the antistatic composition may apply the same content. The translucent resin, the solvent, the initiator, and the additive that may be included in the functional composition and the antistatic composition may be the same or different from each other.

The light transmissive resin may use a photocurable resin, and the photocurable resin may include a (meth) acrylate oligomer and / or a monomer commonly used in the art, but is not limited thereto.

As the photocurable (meth) acrylate oligomer, oligomers commonly used in the art such as epoxy (meth) acrylate and urethane (meth) acrylate can be used, but urethane (meth) acrylate is more preferable.

Although the said urethane (meth) acrylate can manufacture and use the polyfunctional (meth) acrylate which has a hydroxyl group in a molecule | numerator, and the compound which has an isocyanate group in presence of a catalyst, you may purchase and use what is commercially available.

Examples of the (meth) acrylate having a hydroxy group in the molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and caprolactone One or more selected from the group consisting of ring-opening hydroxyacrylate, pentaerythritol tri / tetra (meth) acrylate mixture, and dipentaerythritol penta / hexa (meth) acrylate mixture may be selected, but is not limited thereto.

Moreover, the compound which has the said isocyanate group is, for example, 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 (cyclohexyl isocyanate), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethylxylene-1,3- Derived from diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis (2,6-dimethylphenylisocyanate), 4,4'-oxybis (phenylisocyanate), hexamethylene diisocyanate Trifunctional isocyanate, and trimethane propanol adduct toluene diisocyanae It is at least one selected from the group consisting of, but also not so limited.

As the monomer is commonly used in the art, those having a unsaturated group such as a (meth) acryloyl group, a vinyl group, a styryl group, an allyl group, etc. as a photocurable functional group may be used, and a (meth) acryloyl group may be used. desirable.

Examples of the monomer having a (meth) acryloyl group 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, trimethylol ethane tri (meth) acrylate, 1 , 2,4-cyclohexane tetra (meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate , Dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Ripentaerythritol tri (meth) acrylate, tripentaerythritol hexatri (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (meth) acrylate, hydroxyethyl (meth) acrylate, hydr Oxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth) acrylate, iso-decyl (meth) acrylate, stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylic It may be selected from the group consisting of latex, phenoxyethyl (meth) acrylate, isobornol (meth) acrylate.

The above-mentioned (meth) acrylate oligomers and monomers may be used alone or in combination of two or more.

The light transmitting resin may be included in an amount of 1 to 80 parts by weight based on 100 parts by weight of the functional composition and the antistatic composition, respectively, but is not limited thereto. However, when included in the above range, the hardness is excellent, there is an advantage that can suppress the curling phenomenon. If less than the above range, the hardness of each coating layer may be slightly lowered, and if it exceeds the above range, curling may occur, so it is preferably included within the above range.

The solvent is capable of dissolving or dispersing the above-mentioned composition, so long as it is commonly used in the art can be used without limitation. For example, the solvent may be alcohol-based (methanol, ethanol, isopropanol, butanol, methylcellulose, ethyl solusorb, etc.), ketone-based (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone , Cyclohexanone, etc.), acetate type (ethyl acetate, propyl acetate, normal butyl acetate, tertiary 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.), hexane type (hexane, heptane, octane, etc.), benzene type (benzene, toluene, xylene, etc.), ether type (diethylene glycol dimethyl) Ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propyl Glycol monomethyl ether, etc.) and the like, may be used either alone or in combination of two or more.

The solvent may be used in an amount of 10 to 95 parts by weight based on 100 parts by weight of the functional composition and the antistatic composition, respectively, but is not limited thereto. However, when the solvent is included in the above range, there is an advantage in excellent workability and excellent economic efficiency. When the solvent is included in less than the above range, the viscosity of the composition may be slightly higher, the workability may be lowered slightly. If the solvent exceeds the above range, there is a problem in that the economy is inferior due to time-consuming drying process. It is preferable to use it suitably.

The initiator is used for curing the functional composition and the antistatic composition, and may be a photoinitiator, and the photoinitiator may be used without limitation as long as it is commonly used in the art. For example, one or more selected from the group consisting of hydroxyketones, aminoketones, hydrogen decyclic photoinitiators, and combinations thereof can be used.

Specifically, the photoinitiator is 2-methyl-1- [4- (methylthio) phenyl] 2-morpholinepropanone-1, diphenylketone, benzyldimethyl 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-ke Noloacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexylphenylketone, benzophenone, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide and One or more selected from the group consisting of a combination of these may be used, but is not limited thereto.

The photoinitiator may be used in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of each of the functional composition and the antistatic composition. If it is less than the above range, the curing rate of each composition is slightly slow, and mechanical properties may also be somewhat reduced as uncuring occurs, and if it exceeds the above range, cracks may occur in the coating due to overcuring, so that it is included in the above range. desirable.

The functional composition and the antistatic composition according to the present invention may each include additives commonly used in the art.

Specifically, each of the functional composition and the antistatic composition according to the present invention may include a leveling agent. The leveling agent may be used to impart the smoothness and coating properties of the coating film when coating each of the functional composition and the antistatic composition. For example, the leveling agent may be used by selecting a commercially available leveling agent in the form of silicon, a leveling agent in the form of fluorine, a leveling agent in the form of an acrylic polymer, and more specifically, BYK-323, BYK-331, BYK of BK Chemical Co., Ltd. -333, BYK-337, BYK-373, BYK-375, BYK-377, BYK-378, TEGO Glide 410, TEGO Glide 411, TEGO Glide 415, TEGO Glide 420, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 455, TEGO Rad 2100, TEGO Rad 2200N, TEGO Rad 2250, TEGO Rad 2300, TEGO Rad 2500, 3M's FC-4430, FC-4432, etc. may be used, but is not limited thereto.

In addition, the composition according to the present invention, that is, the functional composition and each of the antistatic composition may further include inorganic nanoparticles that are commonly used to further reinforce the hardness of the coating layer is prepared.

Additives such as the leveling agent and inorganic nanoparticles can be suitably used within the scope of not impairing the object of the present invention, for example, leveling with respect to 100 parts by weight of the total of each of the composition, that is, the functional composition and the antistatic composition. The agent may be used in the range of 0.1 to 1 part by weight, and the inorganic nanoparticles in the range of 1 to 70 parts by weight. The inorganic nanoparticles may be used in a form dispersed in a dispersion medium, and specifically, the inorganic nanoparticles may be nanosilica sol.

In another embodiment of the present invention, a hard coat layer 40 may be further provided on the functional coating layer 20 not in contact with the substrate 10. This is shown in FIG.

In another embodiment of the present invention, a hard coat layer 40 may be further provided on the antistatic coating layer 30 that is not in contact with the substrate 10.

In another embodiment of the present invention, a hard coat layer 40 may be further provided on the functional coating layer 20 and the antistatic coating layer 30 which are not in contact with the substrate 10.

In other words, referring to FIG. 2, the hard coat film 100 according to the present invention may have a hard coat layer 40 on a functional coating layer 20 and / or an antistatic coating layer 30 not in contact with the substrate 10. It may be further provided, preferably, the hard coat film 100 according to the present invention is a hard coat layer 40 on the functional coating layer 20 and the antistatic coating layer 30 not in contact with the substrate 10 It may be further provided, which is shown in FIG.

More specifically, the hard coating film 100 according to the present invention is provided with a hard coat layer 40 on both sides of the outermost and between the functional coating layer 20 and the antistatic coating layer 30, the functional The substrate 10 may be provided between the coating layer 20 and the antistatic coating layer 30.

When the hard coating film 100 is further provided with a hard coat layer 40 there is an advantage that the pencil hardness can be excellent while maintaining the flex resistance.

The hard coat layer 40 may be used commonly used in the art, it does not limit the configuration and manufacturing method of the hard coat layer 40 in the present invention. For example, the hard coat layer 40 may be formed using a method such as a die coater, air knife, reverse roll, spray, blade, casting, gravure, micro gravure.

The hard coat layer 40 may include one or more selected from the group consisting of, for example, acrylic oligomers, inorganic nanoparticles, photoinitiators and solvents. In this case, the photoinitiator and the solvent included in the hard coat layer 40 may be distinguished from the initiator and the solvent, that is, the initiator and the solvent contained in the functional composition or the antistatic composition.

The acryl oligomer may include a polyfunctional (urethane) acrylate, specifically, it is preferable to include a trifunctional or more (urethane) acrylate. When the acrylic oligomer is included in the hard coat layer 40, the hard coat layer 40 may be manufactured with excellent pencil hardness and flex resistance and excellent surface smoothness.

The acrylic oligomer may be included in an amount of 1 to 90 parts by weight, preferably 5 to 85 parts by weight, based on 100 parts by weight of the total hard coat composition. If the acrylic oligomer is included in less than the above range, the hard coat layer 40 may not have sufficient impact resistance, and if it exceeds the above range, it may be somewhat difficult to form a uniform cured coating film due to high viscosity, so within the above range It is preferable to include.

The inorganic nanoparticles may be added to improve the durability of the coating film. The inorganic nanoparticles may have an average particle diameter of 1 to 100 nm, preferably 5 to 50 nm.

When the average particle diameter of the inorganic nanoparticles is less than the above range, aggregation may occur in the composition to form a uniform coating film, and may be somewhat difficult to obtain a desired effect. When the average particle diameter of the inorganic nanoparticles exceeds the above range, since the optical properties of the finally obtained coating film may be slightly lowered, it is preferable to include within the above range.

The material of the inorganic nanoparticles may be a metal oxide, for example Al ₂ O ₃ , SiO ₂ , ZnO, ZrO ₂ , BaTiO ₃ , TiO ₂ , Ta ₂ O ₅ , Ti ₃ O ₅ , ITO, IZO, ATO, ZnO One kind selected from the group consisting of -Al, Nb ₂ O ₃ , SnO, MgO, and combinations thereof may be used, and preferably Al ₂ O ₃ , SiO ₂ , ZrO _2, etc. may be used, but is not limited thereto. .

The inorganic nanoparticles can be prepared and used directly or commercially available. In particular, it is preferable to use commercially available inorganic nanoparticles dispersed in a monomer. Specifically, it is preferable to use a nano silica sol which is SiO ₂ as the inorganic nanoparticles.

The inorganic nanoparticles may be used in an amount of 1 to 70 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the total hard coat composition. If the content of the inorganic nanoparticles is less than the above range, the hardness improvement effect is insignificant, and if it exceeds the above range, cracks may occur on the hardened surface, and thus it is preferably included within the above range.

The photoinitiator may be used for photocuring the hard coat composition, and may be selected without limitation as long as it is commonly used in the art. The photoinitiator can be classified into a type 1 initiator and a tertiary amine covalently generated by the decomposition of molecules due to the difference in chemical structure or molecular bond energy, and can be classified into a hydrogen decyclic type 2 initiator, and a specific example of a type 1 initiator. Is 4-phenoxydichloroacetphenone, 4-t-butyldichloroacetphenone, 4-t-butyltrichloroacetphenone, diethoxy acetphenone, 2-hydroxy-2-methyl-l-phenylpropan-1-one , 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-l-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 4 Acetphenones such as-(2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone and 1-hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, Benzoin, such as benzyl dimethyl ketal, an acylpocipine oxide, a titanocene compound, etc. are mentioned. Specific examples of Type 2 type photoinitiators include benzophenone, benzoylbenzoic acid, benzoyl benzoic acid methyl ether, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzol-4'-methyldiphenyl sulfide, 3,3 '. Tees such as benzophenones such as -methyl-4-methoxy benzophenone, thioxanthone, 2-chlorothioxanthone, 2-methyl thioxanthone, 2, 4-dimethyl thioxanthone and isopropyl thioxanthone Oxanthone etc. are mentioned.

The photoinitiator may be used in one kind or may be used in combination of two or more kinds. In addition, Type 1 and Type 2 may be used alone or in combination. Such a photoinitiator is used in a content capable of sufficiently proceeding photopolymerization, for example, 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight relative to the total solid of the acrylic oligomer. If the content is less than the above range hardening does not proceed sufficiently, it is difficult to implement the mechanical properties or adhesion of the final coating film, on the contrary, if it exceeds the above range may result in poor adhesion or cracking and curling phenomenon due to curing shrinkage It can use suitably within the said range.

The solvent may be used without limitation as long as it is commonly used in the art, for example, alcohol-based (methanol, ethanol, isopropanol, butanol, propylene glycol methoxy alcohol, etc.), ketone-based (methyl ethyl ketone, methyl butyl ketone, Methyl isobutyl ketone, diethyl ketone, dipropyl ketone, etc.), acetates (methyl acetate, ethyl acetate, butyl acetate, propylene glycol methoxy acetate, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, propyl cellosolve Etc.), hydrocarbon type (normal hexane, normal heptane, benzene, toluene, xylene, etc.), etc. are mentioned.

The solvent may be included in 5 to 90 parts by weight, preferably 20 to 70 parts by weight based on 100 parts by weight of the total hard coat composition. When the solvent is less than the above range, the viscosity may be high and the workability may be somewhat reduced. When the solvent exceeds the above range, thickness control of the hard coat layer 40 may be somewhat difficult, and a dry stain may occur, resulting in poor appearance.

The hard coat layer 40 according to the present invention may further include a compound such as urethane acrylate, additives commonly used in the art, and may include, for example, a leveling agent. The leveling agent may be the same as described above, that is, the same content as the leveling agent that can be included in the functional composition and the antistatic composition, the content is 3 to 5 based on 100 parts by weight of the total solid content of the hard coat composition It may be used in parts by weight, but is not limited thereto.

Another aspect of the present invention relates to a window cover film of a flexible display device including the hard coat film 100 described above.

Moreover, another aspect of this invention relates to the image display apparatus containing the window cover film mentioned above.

The image display device may include a liquid crystal display device, an OLED, a flexible display, and the like, but is not limited thereto. Examples of the image display device may include all image display devices known in the art.

The hard coat film 100 according to the present invention has a yellow index (YI) of 1.2 or less, specifically 0.9 or less, more specifically 0.7 or less; Since it includes a functional coating layer 20 and an antistatic coating layer 30 having a surface resistance of 10E + 11Ω / □ or less, when applied to various image display apparatuses, the quality is excellent due to the color compensation function, and due to dust adhesion in the manufacturing process. There is an advantage that the foreign matter defect can be suppressed, the pencil hardness is excellent, and the bending resistance is excellent.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the embodiments according to the present disclosure may be modified in various other forms, and the scope of the present specification is not to be interpreted as being limited to the embodiments described below. The embodiments of the present specification are provided to more fully describe the present specification to those skilled in the art. In addition, "%" and "part" which show content below are a basis of weight unless there is particular notice.

Production Example  One: Hard coat  Composition

To prepare a hard coat composition in the configuration and content according to Table 1. Specifically, 20.5 parts by weight of urethane acrylate (10 functional, Miwon Specialty Chemical, Miramer MU9500), polyfunctional acrylate (trifunctional, Miwon Specialty Chemical, Miramer M3160), 20 weight, containing 20 parts by weight of ethylene oxide as monomo Part nano silica sol (12 nm, 40% solids), 37 parts by weight propylene glycol monomethyl ether, 2 parts by weight photoinitiator (Ciba, I-184), 0.5 parts by weight leveling agent (BYK Chemisa, BYK3570) using a stirrer And blended with a PP filter to prepare a hard coat composition.

Production Example  2 to 5: functional composition

To prepare a hard coat composition in the configuration and content according to Table 1. Specifically, 0.5 parts by weight of Smiplast Violet B was added as a color compensator to 100 parts by weight of methyl ethyl ketone and dissolved using a stirrer.

Thereafter, the hard coat compositions prepared in the same manner as in Preparation Example 1 were prepared, and the color compensators were 300 ppm (Preparation Example 2), 1000 ppm (Preparation Example 3), 40 ppm (Preparation Example 4), and 1200 ppm (preparation) of the total solids of the hard coat composition. Example 5) was added and blended again using a stirrer and then filtered using a filter made of PP material to prepare a functional composition according to Preparation Examples 2 to 5.

Hard Coat Composition Functional composition Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Preparation Example 5 Urethane Acrylate 20.5 20.5 20.5 20.5 20.5 Monomer 20 20 20 20 20 Nano Silica Sol 20 20 20 20 20 solvent 37 37 37 37 37 Photoinitiator 2 2 2 2 2 Leveling agent 0.5 0.5 0.5 0.5 0.5 Sum 100 100 100 100 100 Color compensator (total solids) 0 300 ppm 1000 ppm 40 ppm 1200 ppm

Production Example  6 to 9: antistatic composition

28 parts by weight urethane acrylate (10 functional, Miwon Specialty Chemical, Miramer MU9500), polyfunctional acrylate (trifunctional, Mione Specialty Chemical, Miramer M3160) containing 29 parts by weight of ethylene oxide as monomo, lithium bistrifluoro 5 parts by weight of methanesulfonimide (LiTFSI), 35 parts by weight of propylene glycol monomethyl ether, 2.5 parts by weight of photoinitiator (Ciba, I-184), 0.5 parts by weight of leveling agent (BYK Chemi, BYK3570) using a stirrer Mixing and filtration using a filter of PP material to prepare an antistatic composition according to 6, Preparation Examples 7 to 9 were prepared using the same method as Preparation Example 6 using the configuration and composition of Table 2.

Antistatic composition Preparation Example 6 Preparation Example 7 Preparation Example 8 Preparation Example 9 Urethane Acrylate 28 28 27 30 Monomer 29 29 28 31 Antistatic agent LiTFSI ^* 5 LiPF ₆ ^** 5 LiTFSI 7 LiTFSI 1 solvent 35 35 35 35 Photoinitiator 2.5 2.5 2.5 2.5 Leveling agent 0.5 0.5 0.5 0.5 Sum 100 100 100 100

Lithium bistrifluoromethanesulfonimidate (LiTFSI)

** Lithium hexafluorophosphate (LiPF ₆ )

Hard coating  Manufacture of film: Example  1 to 5 and Comparative example  1, 2

Example 1

To prepare a hard coating film in the configuration according to Table 3. Specifically, after curing the functional composition of Preparation Example 2 on one surface of the optical polyimide film (Mitsubishi Chemical, Neoprem L-3430, 100㎛) and coating the functional layer composition so that the thickness is 5㎛ and 80 degree oven After drying for 2 minutes in a high pressure mercury lamp was cured by irradiation with UV accumulated light amount of 500mJ to form a functional layer. Then, after curing the antistatic composition according to Preparation Example 6 on the other side of the substrate to coat the antistatic coating composition so that the thickness is 1㎛, and dried in an oven at 80 degrees for 2 minutes and cured by irradiating UV accumulated light 500mJ with a high pressure mercury lamp. After the antistatic coating layer was formed. By repeating the above process, using the hard coat composition of Preparation Example 1 to coat the hard coating composition to a thickness of 5㎛ after curing on the upper surface of the functional layer, and dried in an 80 degree oven for 2 minutes, UV integration with a high pressure mercury lamp. After irradiating and curing the light amount of 500mJ to form a hard coat layer to prepare an evaluation sample.

[Examples 2 to 5 and Comparative Examples 1 and 2]

Except that the functional composition, the antistatic composition and the hard coating composition were used in the configuration according to Table 3, respectively, the hard coating film was prepared in the same manner as in Example 1 to prepare an evaluation sample.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Construction layer Hard coat layer Preparation Example 1 Preparation Example 1 Preparation Example 1 Preparation Example 1 Preparation Example 1 Preparation Example 1 Preparation Example 1 Functional coating layer Preparation Example 2 Preparation Example 3 Preparation Example 5 Preparation Example 3 Preparation Example 3 Preparation Example 4 Preparation Example 3 materials 100 μm 100 μm 100 μm 100 μm 100 μm 100 μm 100 μm Antistatic coating layer Preparation Example 6 Preparation Example 6 Preparation Example 6 Preparation Example 8 Preparation Example 7 Preparation Example 6 Preparation Example 9 Evaluation results Hard Coating Film YI Value 1.2 0.5 0.3 0.5 0.5 1.7 0.5 Functional layer surface defect ○ ○ × ○ ○ ○ ○ Antistatic layer surface resistance (Ω / sq) 4.0E + 10 4.0E + 10 4.0E + 10 1.0E + 10 7.0E + 10 4.0E + 10 8.0E + 13 Antistatic layer surface defect ○ ○ ○ × ○ ○ ○ Pencil hardness 4H 4H 4H 4H 4H 4H 4H Flex resistance ○ ○ × × ○ ○ ○

Experimental Example (Evaluation results)

(1) surface resistance

The functional coating layer and the antistatic coating layer according to Examples and Comparative Examples were measured by applying a 500 V voltage using a surface high resistance measuring instrument (Hiresta-up, MCP-HT450, Mitsubishi Corp.) URS probe to measure the surface resistance.

(2) pencil hardness

After setting a pencil in 45 degree-direction under a load of 750g, after fixing a coating film on glass and evaluating 5 times with the pencil which has each pencil hardness, pencil hardness was described by the hardness which does not scratch more than 4 times.

(3) yellowness

Yellowness index was measured using an integrated sphere reflectance meter (Konica Minolta CM-3700D). At this time, the light source uses C and the calculation equation is as follows.

(X, Y, Z means tristimulus values.)

(4) Poor coating surface

After completion of the coating, the coating surface, the coating surface after drying, the functional coating layer after UV curing, and the surface of the antistatic coating layer were evaluated by checking whether bubbles, agglomeration, cracks, etc. occurred.

○: Surface is smooth and nothing is wrong

×: When bubble / lump / crack occurs

(5) flex resistance

The hard coat layer of the hard coat film was turned inward, and folded in half so that the gap between the film planes was 6 mm, and then visually confirmed whether cracks occurred in the folded part when unfolded.

○: No folded part crack

×: folded part crack generation

Referring to Table 3, Examples 1 to 5 have excellent YI values of 0.3 to 1.2, and if the color compensator is used too little as in Comparative Example 1, the YI value will be 1.5 or more. In addition, if the color compensator is used more or less as in Example 3, there is a problem in the coating property of the functional coating layer itself, it is somewhat difficult to obtain a clean coating surface, thereby causing a slight crack during the evaluation of flex resistance. In the case of antistatic performance, Examples 1 to 5 all exhibit 10E + 10 (Ω / sq) or less, and if the content of the antistatic agent is too small as in Comparative Example 2, the antistatic performance is 10E + 13 (Ω / sq). If the amount of the antistatic agent is not used as much as in Example 4, the coating layer is somewhat clean due to the surface defect of the antistatic layer, and it can be seen that cracking occurs in the flex resistance.

[Description of the code]

10: description

20: functional coating layer

30: antistatic coating layer

40: hard coat layer

100: hard coating film

Claims (13)

materials; A functional coating layer provided on one surface of the substrate; And And an antistatic coating layer having a surface resistance of 10E + 11Ω / □ or less provided on the other surface of the substrate. Hard coating film having a YI (yellow index) of 1.2 or less. The method of claim 1, The functional coating layer is a hard coating film comprising a cured product of the functional composition comprising a color compensator. The method of claim 2, The color compensator is a hard coating film containing a blue anthraquinone-based dye. The method of claim 2, The color compensator is a hard coating film that is included in 100 to 1000ppm with respect to the functional composition as a whole. The method of claim 2, The functional composition is a hard coating film further comprises one or more selected from the group consisting of a light-transmissive resin, a solvent, an initiator and an additive. The method of claim 1, The antistatic coating layer is a hard coating film comprising a cured product of the antistatic composition containing a lithium ion compound. The method of claim 6, The lithium ion compound is a hard coating film containing 2 to 5 parts by weight based on 100 parts by weight of the total antistatic composition. The method of claim 6, The antistatic composition is a hard coating film further comprising one or more selected from the group consisting of a light-transmissive resin, a solvent, an initiator and an additive. The method of claim 1, Hard coating film is further provided with a hard coat layer on the functional coating layer not in contact with the substrate.  The method of claim 1, Hard coating film is further provided with a hard coat layer on the antistatic coating layer not in contact with the substrate. The method of claim 1, Hard coating film is further provided with a hard coat layer on the functional coating layer and the antistatic coating layer not in contact with the substrate. A window cover film of a flexible display device comprising the hard coat film according to any one of claims 1 to 11. An image display device comprising the window cover film of claim 12.

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