KR20180090453A - Hard coating film and flexible display window including a touch semsor using the same - Google Patents

Abstract

A hard coating film according to the present invention includes a substrate, a coating layer formed on one side of the substrate, and an antistatic coating layer provided on the other side of the substrate and having a surface resistance of 10E+11Ω/□ or less. Yellow index (YI) of the hard coating film is 1.2 or less.

Description

TECHNICAL FIELD [0001] The present invention relates to a flexible display window including a hard coating film and a touch sensor having the hard coating film.

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

With the recent development of mobile devices such as smart phones and tablet PCs, thinner and slimmer display substrates have been required. Glass or tempered glass is generally used as a material having excellent mechanical properties on a display window or a front plate of such a mobile device. However, glass causes a heavy weight of the mobile device due to its own weight, and there is a problem of breakage due to an external impact, and it is difficult to realize a flexible display.

Plastic resins are being studied as a substitute for glass. The plastic resin composition is lightweight and less likely to be broken, and is most suitable for a flexible and flexible mobile device. Particularly, substrate films capable of touch driving, preventing dust adhesion, and having properties of surface resistance, pencil hardness and flexural resistance are being studied, and polyimide films are emerging as an alternative. However, such a hard coating film based on a polyimide film also has a high YI (yellow index) value.

Typically, a hardcoat film comprises a substrate and a hardcoat layer. If the YI value is high, there is a problem that the image display device such as LCD and LED equipped with the hard coating film can not display the desired color and the quality is degraded. Therefore, it is necessary to increase the amount of backlight to compensate the YI value or to adjust the color balance Which can also cause the battery to run down

Korean Unexamined Patent Publication No. 1998-0020031 relates to a hard coating composition for antistatic photo-curing and a coating method for the same, wherein an antistatic hard coating composition for a transparent plastic comprises 10-60% by weight of hexafunctional acrylic monomer, A photoinitiator, 3 to 7% by weight of a photoinitiator, 3 to 40% by weight of a permanent antistatic agent for ultraviolet ray curing, 0 to 10% by weight of conductive titania, and 4 to 20% by weight of a UV stabilizer And an antistatic photo-curing hard coating composition.

However, the above literature also fails to provide an alternative for YI reduction. Therefore, development of a hard coating film capable of reducing YI as well as prevention of adsorption of static electricity is required.

Korean Patent Publication No. 1998-0020031 (Jun. 25, 1998)

An object of the present invention is to provide a hard coating 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 aforementioned hard coating film.

The hard coating film of the present invention for achieving the above object 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 + 11? /? Or less, wherein YI (yellow index) is 1.2 or less.

The present invention also provides a window cover film of a flexible display device provided with the above-mentioned hard coating film.

The present invention also provides an image display apparatus including the above-described window cover film.

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

Further, the image display device including the hard coating film according to the present invention has an advantage that the YI value is low.

Figures 1 to 3 illustrate hard coating films according to some embodiments of the present invention.

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

When a member is referred to as being " on "another member in the present invention, this includes not only when a member is in contact with another member but also when another member exists between the two members.

Whenever a part is referred to as "including " an element in the present invention, it is to be understood that it may include other elements as well, without departing from the other elements unless specifically stated otherwise.

< Hard coating  Film>

One aspect of the present invention relates to an article comprising a substrate 10; A functional coating layer 20 provided on one surface of the substrate 10; And an antistatic coating layer 30 provided on the other surface of the substrate 10 and having a surface resistance of 10E + 11? /? Or less, and 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 which are commonly used in the art within the scope of not impairing the object of the present invention.

In the present invention, the base material (10) is not limited as long as it is a transparent base material and is a transparent polymer film.

In the present invention, the term "transparent" means that the transmittance of the visible ray 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, polyether imide, polyacryl, polyimide, polymethyl methacrylate, polyethylene terephthalate, polycarbonate However, the present invention is not limited thereto, and the polymers may be used alone or in combination of two or more.

The substrate 10 may be subjected to a plasma or corona treatment, but the present invention 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 contacting the substrate 10 and the antistatic coating layer 30 is increased.

In order to use the hard coating film 100 as a window cover film, it is required to be able to withstand a high-temperature process in the case of post-processing such as black matrix or anti-fingering process, It is most preferable to use a mid film.

The thickness of the film of the substrate 10 may be 8 to 1000 탆, specifically 40 to 100 탆. When the thickness of the film of the base material 10 is in the above range, the strength of the film is high, so that the workability is excellent and the transparency is prevented from being lowered, and the hard coating film 100 can be lightened.

1, a functional coating layer 20 is provided on one surface of the substrate 10, and a surface of the substrate 10 on which the functional coating layer 20 is not provided, An antistatic coating layer 30 is provided.

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

An embodiment of the present invention relates to a hard coating film (100), wherein the functional coating layer (20) comprises a cured product of a functional composition comprising a color compensation agent.

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

For example, the functional coating layer 20 may be formed by a method such as die coater, air knife, reverse roll, spray, blade, casting, gravure, microgravure, and spin coating.

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

When the blue-based anthraquinone-based dye is included in the functional coating layer 20, the functional coating layer emits blue light as a whole, and YI can be reduced because the overall yellowness of the film is reduced.

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

The blue series of anthraquinone dyes include, for example, MACROLEX (TM) Violet B (commercially available from 1-Hydroxy-4- (p-toluidino) anthraquinone) Lanxess And MACROLEX Blue RR, commercially available from Sumitomo Chemical Co., Ltd., MACROLEX Blue 3R, SUMIPLAST Violet RR, SUMIPLAST Violet B, SUMIPLAST Blue OR, DIARESIN Violet D commercially available from Mitsubishi Chemical, DIARESIN Blue G, Blue N, and the like.

Preferably, the anthraquinone-based dye is dissolved in an organic solvent, and 1-hydroxy-4- (p-toluidine) anthraquinone is preferable, and SUMIPLAST Violet B is a commercially available product.

In another embodiment of the present invention, the color compensation agent may be contained in an amount of 100 to 1000 ppm, preferably 200 to 1000 ppm, more preferably 300 to 1000 ppm, based on the total solid content of the functional composition.

When the color-compensating agent is contained within the above-mentioned range, it is advantageous because it is advantageous in that the YI reduction is maximized while satisfying flexural resistance and the like. When the color compensating agent is contained in an amount less than the above range, the reduction of YI may be somewhat insufficient. If the color compensating agent is contained in the above range, the solubility of the color compensating agent is low and an excess amount is required. It is preferable to satisfy the above range.

Another embodiment of the present invention relates to a hard coating 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 for manufacturing the antistatic coating layer 30 using the antistatic composition is not limited to the present invention.

For example, the antistatic coating layer 30 may be formed by a die coater, an air knife, a reverse roll, a spray, a blade, a casting, a gravure, a microgravure, or the like.

Examples of the lithium ion compound include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium hexafluoroarsenate (LiAsF ₆ ), lithium tetrafluoroborate (LiBF ₄ ) (LiTF), lithium bistrifluoromethanesulfonimidate (LiTFSI), lithium bistrifluoromethanesulfonimide (LiBETI), and lithium bisfluoro (perfluoroalkylsulfonic acid) (LiFSI), super acid lithium salt (LiSA: C _n F _{2n + 1} SO ₃ Li, n = 4,8,10), lithium polyanion salt system, 1,2,3-dithiazolidin- , 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), a fluorine-containing lithium salt, lithium-4 , 5-dicyano-1,2,3-triazolate (LiDCTA), lithium tetracyanoborate (LiB (CN) ₄ ) and the like, but not limited thereto, .

Although not wishing to be bound by theory, the lithium ion compound functions to improve the electrical conductivity of the hard coat layer 40 by bonding with oxygen atoms in a light-transmitting resin to be described later. At the same time, at the same time, a flexible ion-binding site is formed not in the covalent bond in the hard coat layer 40, thereby acting as a semi-crosslinked bond in hardness measurement to improve the hardness and at the same time, It is possible to simultaneously improve the hardness and flexibility by exhibiting the effect of improving the flexibility due to the effect that the bonds are separated freely and are recombined at other sites.

That is, the antistatic coating layer 30 according to the present invention has an advantage that the surface resistance is 10E + 11? /? Or less by including the lithium ion compound. Therefore, there is little foreign matter caused by static electricity, which is advantageous in terms of process and cost.

The lithium ion compound may be contained 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, antistatic performance and surface coating property can be simultaneously achieved . If the amount of the lithium ion compound is less than the above range, the improvement of the electrical conductivity may be insufficient and the antistatic function may be insufficient. When the amount exceeds the above range, the antistatic coating layer The mechanical properties of the resin layer 30 may be deteriorated.

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

In still another embodiment of the present invention, the antistatic composition may further comprise at least one member selected from the group consisting of a light-transmitting resin, a solvent, an initiator and an additive.

The same contents can be applied to the light-transmitting resin, solvent, initiator and additive which can be contained in the functional composition and the antistatic composition. The light-transmitting resin, solvent, initiator, and additive that may be contained in the functional composition and the antistatic composition may be the same or different, respectively.

 The light transmitting resin may be a photocurable resin, and the photocurable resin may include (meth) acrylate oligomer and / or a monomer commonly used in the art.

As the photo-curable (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.

The urethane (meth) acrylate can be prepared by using a compound having a polyfunctional (meth) acrylate having a hydroxyl group in the molecule and an isocyanate group in the presence of a catalyst, but commercially available urethane (meth) acrylate may be used.

The (meth) acrylate having a hydroxy group in the molecule includes, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 4-hydroxybutyl A mixture of pentaerythritol tetra (meth) acrylate, and a mixture of dipentaerythritol penta / hexa (meth) acrylate, may be used.

Examples of the compound having an isocyanate group 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-cyclohexane diisocyanate, Methylenebis (cyclohexylisocyanate), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethyl xylene- Diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis (2,6-dimethylphenyl isocyanate), 4,4'-oxybis (phenylisocyanate), hexamethylene diisocyanate And trifunctional isocyanate, and trimethanepropanol adduct. Toluene diisocyanate It is at least one selected from the group consisting of, but also not so limited.

The monomer may be a photo-curable functional group having an unsaturated group such as a (meth) acryloyl group, a vinyl group, a styryl group or an allyl group in the molecule, and the (meth) acryloyl group may be a 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) (Meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipropylene glycol di (Meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tetra , Dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (Meth) acrylate, stearyl (meth) acrylate, tetrahydroperfuryl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, isobornole (meth) acrylate, and the like.

The (meth) acrylate oligomer and the monomer exemplified above may be used alone or in combination of two or more.

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

The above-mentioned solvent is capable of dissolving or dispersing the above-mentioned composition, and is not limited as long as it is commonly used in the art. For example, the solvent may be at least one selected from the group consisting of alcohols (methanol, ethanol, isopropanol, butanol, methylcellulose, ethylsorbox, etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, , Cyclohexanone and the like), an acetate type (ethyl acetate, propyl acetate, n-butyl acetate, tertiary butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate Hexane, heptane, and octane), benzene (benzene, toluene, xylene, and the like), ether (diethylene glycol dimethyl (meth) acrylate and the like), propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate, 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 total of the functional composition and the antistatic composition, but is not limited thereto. However, when the solvent is contained within the above range, there is an advantage in that the workability is excellent and the economical efficiency is excellent. If the amount of the solvent is less than the above range, the viscosity of the composition may be somewhat high and the workability may be somewhat lowered. If the amount of the solvent is more than the above range, It is preferable to use them appropriately.

The initiator is used for curing each of the functional composition and the antistatic composition. The initiator may be a photoinitiator, and the photoinitiator may be used without limitation if it is conventionally used in the art. For example, at least one selected from the group consisting of hydroxy ketones, aminoketones, hydrogen recycling type photoinitiators, and combinations thereof can be used.

Specific examples of the photoinitiator include 2-methyl-1- [4- (methylthio) phenyl] 2-morpholinepropanone-1, diphenyl ketone, benzyldimethyl ketal, 2- Phenyl-1-one, 4-hydroxycyclophenyl ketone, 2,2-dimethoxy-2-phenyl-acetophenone, anthraquinone, fluorene, triphenylamine, carbazole, Phenol, 4,4-diaminobenzophenone, 1-hydroxycyclohexyl phenyl ketone, benzophenone, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide and And combinations thereof. However, the present invention 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 the total of the functional composition and the antistatic composition. If the amount is less than the above range, the curing speed of each composition is somewhat late and unstructured, mechanical properties may be somewhat lowered. If the amount is out of the above range, cracks may occur in the coating due to overcuring, desirable.

The functional composition and the antistatic composition according to the present invention may each contain additives conventionally 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 smoothness and coatability of a coating film when each of the functional composition and the antistatic composition is coated. For example, the leveling agent can be selected from commercially available silicone type leveling agents, fluorine type leveling agents and acrylic polymer type leveling agents. More specifically, BYK-323, BYK-331, BYK TEGO Glide 411, TEGO Glide 415, TEGO Glide 420, TEGO Glide 432, TEGO Glide 435, TEGO Glide 435, BYK-377 But are not limited to, Glide 440, TEGO Glide 450, TEGO Glide 455, TEGO Rad 2100, TEGO Rad 2200N, TEGO Rad 2250, TEGO Rad 2300, TEGO Rad 2500, FC-4430 and FC-4432 from 3M.

In addition, each of the compositions according to the present invention, that is, the functional composition and the antistatic composition may further include inorganic nanoparticles conventionally used to further reinforce the hardness of the coating layer to be produced.

Additives such as the leveling agent and inorganic nanoparticles can be suitably used within a range that does not impair the object of the present invention. For example, when the leveling agent is added to 100 parts by weight of the composition, that is, the entirety of each of the functional composition and the antistatic composition, 0.1 to 1 part by weight of the inorganic nanoparticles, and 1 to 70 parts by weight of the inorganic nanoparticles. The inorganic nanoparticles may be dispersed in a dispersion medium. Specifically, the inorganic nanoparticles may be nanosilica sol.

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

The 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.

2, the hard coating film 100 according to the present invention includes a hard coat layer 40 on the functional coating layer 20 not in contact with the substrate 10 and / or on the antistatic coating layer 30, The hard coating film 100 according to the present invention preferably includes a hard coat layer 40 on the functional coating layer 20 not in contact with the substrate 10 and the antistatic coating layer 30, 3, which is shown in Fig.

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

When the hard coating film 100 further includes the hard coat layer 40, it has an advantage that the pencil hardness is excellent and the bending resistance can be maintained.

The hard coat layer 40 may be one that is commonly used in the art, and the present invention does not limit the structure and the manufacturing method of the hard coat layer 40. For example, the hard coat layer 40 may be formed using a die coater, an air knife, a reverse roll, a spray, a blade, casting, gravure, microgravure, or the like.

The hard coat layer 40 may include at least one selected from the group consisting of, for example, acrylic oligomers, inorganic nanoparticles, photoinitiators and solvents. At this time, the photoinitiator and the solvent contained in the hard coat layer 40 may be distinguished from the initiators and the solvents mentioned above, that is, the initiators and the solvents contained in the functional composition or the antistatic composition.

The acryl oligomer may include a polyfunctional (urethane) acrylate, and more preferably a trifunctional or more (urethane) acrylate. When the acryl oligomer is included in the hard coat layer 40, the hard coat layer 40 having excellent pencil hardness and flexural resistance and excellent surface smoothness can be produced.

The acrylic oligomer may be contained 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 entire hard coat composition. When the acryl oligomer is contained in the range below the above range, the hard coat layer 40 can not have sufficient impact resistance, and if it exceeds the above range, formation of a uniform cured coating film due to high viscosity may be somewhat difficult. .

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.

If the average particle diameter of the inorganic nanoparticles is less than the above range, aggregation may occur in the composition and it may be difficult to form a uniform coating film, and it may be difficult to obtain the desired effect. When the average particle diameter of the inorganic nanoparticles exceeds the above range, the optical characteristics of the finally obtained coating film may be somewhat lowered, so that it is preferable to include the inorganic nanoparticles 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 -Al, Nb ₂ O _3, SnO, MgO, and may be used one selected from the group consisting of, but preferably be used as the _{Al 2 O 3, SiO 2,} ZrO 2 are not limited to, .

The inorganic nanoparticles can be manufactured directly or commercially available. Particularly, commercially available inorganic nano-particles are preferably dispersed in monomers. Specifically, it is preferable to use nano-silica sol of 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 fine particles is less than the above range, the effect of improving the hardness is insufficient. If the content is above the above range, cracks may occur in the light screen, and therefore, the content is preferably 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 may be classified into a Type 1 initiator in which a radical is generated by decomposition of a molecule due to a difference in chemical structure or molecular binding energy and a Type 2 initiator of a hydrogen recycling type in combination with a tertiary amine. Specific examples of the Type 1 initiator include 4-t-butyldichloroacetophenone, 4-t-butyl trichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan- , 1- (4-dodecylphenyl) -2-hydroxypropyl-2-methylpropan-1- Acetophenones such as - (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone and 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, And benzyl dimethyl ketal; acylphosphine oxides; and titanocene compounds. Specific examples of the Type 2 type photosensitizer include benzophenone, benzoyl benzoic acid, benzoyl benzoic acid methyl ether, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3 ' Methyl-4-methoxybenzophenone and the like, benzophenones such as thioxanthone, 2-chromothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone and isopropylthioxanthone Oxanone, and the like.

These photoinitiators may be used alone or in combination of two or more. Type 1 and Type 2 may be used alone or in combination. Such a photoinitiator is used in an amount sufficient to promote photopolymerization. For example, it is used in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on the total solid content of the acrylic oligomer. If the content is less than the above range, hardening does not proceed sufficiently and it is difficult to realize the mechanical properties and adhesive force of the finally obtained coating film. On the other hand, if the content exceeds the above range, poor adhesion, cracking and curling due to hardening shrinkage may occur , And can be appropriately used within the above range.

The solvent is not limited as long as it is commonly used in the art, and examples thereof include alcohols (methanol, ethanol, isopropanol, butanol, propylene glycol methoxy alcohol and the like), ketones (methyl ethyl ketone, methyl butyl ketone, Methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone and dipropyl ketone), acetate type (methyl acetate, ethyl acetate, butyl acetate, propylene glycol methoxy acetate and the like), cellosolve type (methyl cellosolve, ethyl cellosolve, Etc.), hydrocarbons (normal hexane, normal heptane, benzene, toluene, xylene and the like).

The solvent may be included in an amount of 5 to 90 parts by weight, preferably 20 to 70 parts by weight, based on 100 parts by weight of the entire hard coat composition. If the amount of the solvent is less than the above range, the workability may be lowered due to the high viscosity. If the amount of the solvent is more than the above range, the thickness of the hard coat layer 40 may be somewhat difficult to control, and drying unevenness may occur.

The hard coat layer 40 according to the present invention may further comprise a compound such as urethane acrylate commonly used in the art, an additive, for example, a leveling agent. The leveling agent may be the same as the leveling agent described above, that is, the leveling agent that can be contained in the functional composition and the antistatic composition, and the content thereof is preferably 3 to 5 parts by weight per 100 parts by weight of the total solid content of the hard coat composition. But it is not limited thereto.

Another aspect of the invention relates to a window cover film of a flexible display device comprising the hard coating film 100 described above.

Further, another aspect of the present invention relates to an image display apparatus including the above-described window cover film.

The image display device may include a liquid crystal display device, an OLED, a flexible display, and the like. However, the present invention is not limited thereto, and any image display device known in the art can be applied.

The hard coating film 100 according to the present invention has a YI (yellow index) of 1.2 or less, specifically 0.9 or less, more specifically 0.7 or less; The functional coating layer 20 and the antistatic coating layer 30 having a surface resistance of 10E + 11? /? Or less are superior in quality due to the color compensation function when applied to various image display devices, It is possible to suppress foreign matter defects, an excellent pencil hardness, and an excellent flexural resistance.

Hereinafter, the present invention will be described in detail by way of examples to illustrate the present invention. However, the embodiments according to the present disclosure can be modified in various other forms, and the scope of the present specification is not construed as being limited to the above-described embodiments. Embodiments of the present disclosure are provided to more fully describe the present disclosure to those of ordinary skill in the art. In the following, "%" and "part" representing the content are by weight unless otherwise specified.

Manufacturing example  One: Hard coat  Composition

Hard coat compositions were prepared according to the compositions and contents shown in Table 1 below. Specifically, 20.5 parts by weight of urethane acrylate (10-functional, Miryour Specialty Chemicals, Miramer MU9500), 20 parts by weight of ethylene oxide as a mono-functional polyfunctional acrylate (trifunctional functional group, Miramer M3160) 37 parts by weight of propylene glycol monomethyl ether, 2 parts by weight of photoinitiator (Shibasa, I-184), and 0.5 parts by weight of leveling agent (BYK Chemicals, BYK3570) The mixture was filtered using a PP filter to produce a hard coat composition.

Manufacturing example  2 to 5: Functional composition

Hard coat compositions were prepared according to the compositions and contents shown in Table 1 below. Specifically, 0.5 parts by weight of Sumiplast Violet B as a color compensation agent was added to 100 parts by weight of methyl ethyl ketone and dissolved using a stirrer.

Then, the hard coat compositions prepared in the same manner as in Preparation Example 1 were respectively prepared. The hard coat compositions were prepared in the same manner as in Preparation Example 1 except that the color compensators were 300 ppm (Production Example 2), 1000 ppm (Production Example 3), 40 ppm Example 5). The mixture was blended again using a stirrer, and then filtered using a PP-made filter to prepare functional compositions according to Production Examples 2 to 5.

Hard coat composition Functional composition Production Example 1 Production Example 2 Production Example 3 Production Example 4 Production 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 Compensation (relative to total solids) 0 300ppm 1000ppm 40 ppm 1200ppm

Manufacturing example  6 to 9: antistatic composition

28 parts by weight of urethane acrylate (10-functional, Miryer Specialty Chemicals, Miramer MU9500), 29 parts by weight of ethylene oxide as a mono-functional polyfunctional acrylate (trifunctional, Miwon Specialty Chemicals, Miramer M3160), lithium bistrifluoro 5 parts by weight of methanesulfonimidate (LiTFSI), 35 parts by weight of propylene glycol monomethyl ether, 2.5 parts by weight of photoinitiator (Shibasai, I-184) and 0.5 parts by weight of leveling agent (BYKEMASA, BYK3570) And an antistatic composition according to item 6 was prepared by filtration using a PP filter. Production examples 7 to 9 were produced using the same method as in production example 6, using the composition and composition of the following table 2.

Antistatic composition Production Example 6 Production Example 7 Production Example 8 Production Example 9 Urethane acrylate 28 28 27 30 Monomer 29 29 28 31 Antistatic agent LiTFSI ^*
5 LiPF ₆ ^**
5 LiTFSI
7 LiTFSI
One 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 bistrifluoromethane sulfonimidate (LiTFSI)

** Lithium hexafluorophosphate (LiPF ₆ )

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

[Example 1]

Hard coating films were prepared in accordance with Table 3 below. Specifically, a functional layer composition was coated on one surface of an optical polyimide film (Mitsubishi Gas Chemical, Neoprim L-3430, 100 μm) to cure the functional composition of Preparation Example 2 to a thickness of 5 μm, For 2 minutes, and irradiated with a UV light intensity of 500 mJ with a high-pressure mercury lamp, followed by curing to form a functional layer. Then, the antistatic composition according to Production Example 6 was coated on the other side of the base material after curing so as to have a thickness of 1 占 퐉, dried in an oven at 80 ° C for 2 minutes, irradiated with a UV light intensity of 500 mJ with a high pressure mercury lamp, To form an antistatic coating layer. The above process was repeated to coat the hard coat composition on the upper surface of the functional layer using the hard coat composition of Preparation Example 1 so as to have a thickness of 5 占 퐉 and then dried in an oven at 80 ° C for 2 minutes. Irradiated with light of 500 mJ and cured, and then a hard coat layer was formed to prepare an evaluation sample.

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

A hard coating film was produced in the same manner as in Example 1 except that the functional composition, the antistatic composition and the hard coating composition were respectively used in the compositions shown in Table 3 below to prepare evaluation samples.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Constituent layer Hard coat layer Production Example 1 Production Example 1 Production Example 1 Production Example 1 Production Example 1 Production Example 1 Production Example 1 Functional coating layer Production Example 2 Production Example 3 Production Example 5 Production Example 3 Production Example 3 Production Example 4 Production Example 3 materials 100 탆 100 탆 100 탆 100 탆 100 탆 100 탆 100 탆 Antistatic coating layer Production Example 6 Production Example 6 Production Example 6 Production Example 8 Production Example 7 Production Example 6 Production 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 defective ○ ○ ○ × ○ ○ ○ Pencil hardness 4H 4H 4H 4H 4H 4H 4H Flexibility ○ ○ × × ○ ○ ○

Experimental Example (Evaluation results)

(1) Surface resistance

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

(2) Pencil hardness

After setting the pencil in a direction of 45 degrees under a load of 750 g, the coating film was fixed on a glass, and after the evaluation with a pencil having each pencil hardness, the pencil hardness was indicated by hardness not scratching four or more times.

(3) Yellowness

The Yellow Index was measured using an integral spherical reflectance meter (Konica Minolta CM-3700D). At this time, the light source uses C, and the calculation formula is as follows.

(X, Y, and Z represent tristimulus values.)

(4) Poor surface of coating layer

After completion of the coating, the coating surface and the surface after drying, the functional coating layer after the UV curing, and the surface of the antistatic coating layer were checked for bubbles, lumps, and cracks.

○: Surface condition is smooth and there is no abnormality

X: Bubbles / aggregation / cracks occurred

(5) Flexibility

The hard coat layer of the hard coating film was oriented inward and folded in half so that the gap between the film faces was 6 mm. Then, when the hard coat layer was spread again, it was visually confirmed whether cracks occurred in the folded portions.

O: Creased cracks in the folded part

X: Crease of folded portion

Referring to Table 3, the YI value of Examples 1 to 5 is as high as 0.3 to 1.2, and when the color compensating agent is used too little as in Comparative Example 1, the YI value becomes 1.5 or more. Also, if the color compensating agent is used in a somewhat larger amount as in Example 3, there is a problem in coatability of the functional coating layer itself, and it is somewhat difficult to obtain a clean coated surface, thereby causing a crack to be generated even when evaluating the bending resistance. In the case of the antistatic performance, Examples 1 to 5 all show 10E + 10 (Ω / sq) or less. When the content of the antistatic agent is too small as in Comparative Example 2, 10E + 13 (Ω / If the content of the antistatic agent is slightly higher than that of the antistatic agent as in Example 4, the coating layer is not clean due to the surface defects of the antistatic layer, and cracking occurs in the bending resistance.

10: substrate
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 provided on the other surface of the substrate and having a surface resistance of 10E + 11? /? Or less,
A hard coating film having a YI (yellow index) of 1.2 or less. The method according to claim 1,
Wherein the functional coating layer comprises a cured product of a functional composition comprising a color compensation agent. 3. The method of claim 2,
Wherein the color compensation agent comprises a blue series of anthraquinone dyes. 3. The method of claim 2,
Wherein the color compensation agent is contained in an amount of 100 to 1000 ppm relative to the entirety of the functional composition. 3. The method of claim 2,
Wherein the functional composition further comprises at least one selected from the group consisting of a light transmitting resin, a solvent, an initiator and an additive. The method according to claim 1,
Wherein the antistatic coating layer comprises a cured product of an antistatic composition comprising a lithium ion compound. The method according to claim 6,
Wherein the lithium ion compound is contained in an amount of 2 to 5 parts by weight based on 100 parts by weight of the total antistatic composition. The method according to claim 6,
Wherein the antistatic composition further comprises at least one selected from the group consisting of a light transmitting resin, a solvent, an initiator, and an additive. The method according to claim 1,
And a hard coat layer is further provided on the functional coating layer not in contact with the substrate. The method according to claim 1,
And a hard coat layer is further provided on the antistatic coating layer not in contact with the substrate. The method according to claim 1,
And a hard coat layer is further provided on the functional coating layer and the antistatic coating layer which are 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 a window cover film according to claim 12.

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