KR20170019120A - Hard Coating Composition and Hard Coating Film Using the Same - Google Patents

Abstract

Provided is a hard coating composition which comprises: cellulose having a (meth)acrylate group; polyfunctional urethane (meth)acrylate having a cyclohexyl group; polyfunctional (meth)acrylate having an ethylene glycol group; a photoinitiator; and a solvent. Also, provided are a hard coating film formed by using the same, and an image display device having the hard coating film. According to the present invention, the hard coating film exhibits excellent high hardness and outstanding abrasion resistance as well as excellent adhesiveness and curling and crack properties.

Description

[0001] The present invention relates to a hard coating composition and a hard coating film using the same,

The present invention relates to a hard coating composition and a hard coating film using the hard coating composition. More particularly, the present invention relates to a hard coating composition having excellent hardness and flexibility and a hard coating film formed using the hard coating composition, .

The hard coating film is used for surface protection for image display devices such as a liquid crystal display device, an electroluminescence (EL) display device, a plasma display (PD), and a field emission display (FED).

In recent years, a flexible display device capable of maintaining the display performance even if bent like paper by using a flexible material such as plastic instead of a conventional glass substrate has rapidly emerged as a next-generation display device, and hardness There is a demand for a hard coating film which is high in high abrasion resistance, does not cause a curl phenomenon at the edge of the film during the production process or use, and has appropriate flexibility and does not crack.

Korean Patent Laid-Open Publication No. 2011-0114304 discloses that a water-repellent hard coating composition comprising a (meth) acrylate compound, a photoinitiator, a light transmitting particle, a cellulose compound and a solvent improves the dispersibility of the fine particles and has excellent coating uniformity .

However, the hard coating composition has a problem that it is difficult to secure sufficient hardness and flexibility to be applicable to a flexible display device.

Korean Patent Publication No. 2011-0114304

It is an object of the present invention to provide a hard coating composition which can be used for producing a hard coating film having excellent hardness and flexibility.

It is another object of the present invention to provide a hardcoat film formed using the hardcoat composition.

It is still another object of the present invention to provide an image display device provided with the hard coating film.

On the other hand, the present invention relates to a hard coating composition comprising a cellulose having a (meth) acrylate group, a polyfunctional (meth) acrylate having a cyclohexyl group and a polyfunctional (meth) acrylate having an ethylene glycol group, a photoinitiator and a solvent .

In one embodiment of the present invention, the cellulose having the (meth) acrylate group may be a compound represented by the following formula (1).

[Chemical Formula 1]

Wherein R ₁ , R ₂ and R ₃ are each independently hydrogen or a (meth) acryloyl group,

At least one of R ₁ , R ₂ and R ₃ is a (meth) acryloyl group,

n is an integer from 2 to 50;

In one embodiment of the present invention, the polyfunctional urethane (meth) acrylate having a cyclohexyl group can be prepared by a condensation reaction between a diisocyanate having a cyclohexyl group and a polyfunctional (meth) acrylate having a hydroxy group.

In one embodiment of the present invention, the polyfunctional (meth) acrylate having an ethylene glycol group is obtained by subjecting a polyhydric alcohol to an addition reaction with ethylene oxide to obtain a polyfunctional alcohol having an ethylene glycol group, and adding (meth) acrylic acid Can be produced by a condensation reaction.

The hard coating composition according to one embodiment of the present invention may further comprise inorganic nanoparticles.

On the other hand, the present invention provides a hard coating film formed using the hard coating composition.

On the other hand, the present invention provides an image display device provided with the hard coating film.

The hard coating film formed using the hard coating composition according to the present invention has high hardness and excellent scratch resistance as well as excellent adhesiveness, curling and cracking properties, and thus can be effectively used for a window of a flexible display device.

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

One embodiment of the present invention relates to a hard coating (coating) comprising a cellulose having a (meth) acrylate group, a polyfunctional (meth) acrylate having a cyclohexyl group and a polyfunctional (meth) acrylate having an ethylene glycol group, a photoinitiator and a solvent ≪ / RTI >

In one embodiment of the present invention, the cellulose having the (meth) acrylate group has a cyclic structure with a (meth) acrylate group capable of participating in the photo-curing, so that the shrinkage after curing is reduced, curl is reduced, A hard hard coating layer can be obtained.

The cellulose having the (meth) acrylate group may be contained in an amount of 10 to 40% by weight, preferably 20 to 30% by weight based on 100% by weight of the entire acrylate monomer. If it is less than 10% by weight, it is difficult to exhibit the bending property, and when it is more than 40% by weight, it may be difficult to impart hardness characteristics to the coating layer due to the presence of unreacted functional groups due to the steric hindrance effect.

In one embodiment of the present invention, the cellulose having the (meth) acrylate group may be a compound represented by the following formula (1).

[Chemical Formula 1]

Wherein R ₁ , R ₂ and R ₃ are each independently hydrogen or a (meth) acryloyl group,

At least one of R ₁ , R ₂ and R ₃ is a (meth) acryloyl group,

n is an integer from 2 to 50;

The cellulose having the (meth) acrylate group may have a number average molecular weight of 10,000 to 100,000 and a diameter of 10 to 60 탆.

The cellulose having the (meth) acrylate group can be prepared by condensation reaction of (meth) acrylic acid with the hydroxyl group of cellulose.

The cellulose may be commercially available or may be extracted from coconut, corn, cotton, hemp, etc. according to methods known in the art.

In one embodiment of the present invention, the polyfunctional urethane (meth) acrylate having a cyclohexyl group is used as a component for improving mechanical properties, particularly hardness, of a film to be coated, To 70% by weight. If it is less than 10% by weight, mechanical properties, especially hardness, may be lowered. If it is more than 70% by weight, shrinkage may be increased and curling, breakage or cracking of the film may occur.

The polyfunctional urethane (meth) acrylate having a cyclohexyl group can be prepared by condensation reaction of a diisocyanate having a cyclohexyl group with a polyfunctional (meth) acrylate having a hydroxy group.

The diisocyanate having a cyclohexyl group may be 1,4-cyclohexyl diisocyanate, isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and the like, but is not limited thereto.

The polyfunctional (meth) acrylate having a hydroxy group may be specifically exemplified by trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, no.

In one embodiment of the present invention, the polyfunctional urethane (meth) acrylate having a cyclohexyl group may include at least one member selected from the group consisting of compounds represented by the following formulas (2) to (3).

(2)

(3)

In one embodiment of the present invention, the polyfunctional (meth) acrylate having an ethylene glycol group is a component for imparting flexibility to a film to be coated, and is contained in an amount of 10 to 40% by weight based on 100% by weight of the entire acrylate monomer . If it is less than 10% by weight, flexibility may be insufficient, and breakage or cracking of the coating film may occur. If it is more than 40% by weight, mechanical properties may be deteriorated and surface scratches and pencil hardness may be lowered.

The polyfunctional (meth) acrylate having an ethylene glycol group can be produced by subjecting a polyhydric alcohol to an addition reaction with ethylene oxide to obtain a polyfunctional alcohol having an ethylene glycol group and subjecting the polyfunctional alcohol to a condensation reaction with (meth) acrylic acid .

Specific examples of the polyhydric alcohol include, but are not limited to, glycerol, trimethylol propane, pentaerythritol, dipentaerythritol and the like.

Specific examples of the polyfunctional (meth) acrylate having an ethylene glycol group include trimethylolpropane (EO) ₃ Tri (meth) acrylate, trimethylolpropane (EO) ₆ Tri (meth) acrylate, trimethylolpropane (EO) ₉ Tri (meth) acrylate, glycerin (EO) ₃ Tri (meth) acrylate, glycerin (EO) ₆ Tri (meth) acrylate, glycerin (EO) ₉ Pentaerythritol (EO) ₄ tetra (meth) acrylate, pentaerythritol (EO) ₈ tetra (meth) acrylate, pentaerythritol (EO) ₁₂ Such as tetra (meth) acrylate, dipentaerythritol (EO) ₆ hexa (meth) acrylate, dipentaerythritol (EO) ₁₂ hexa (meth) acrylate, dipentaerythritol (EO) ₁₈ hexa (meth) acrylate have.

In one embodiment of the present invention, the polyfunctional (meth) acrylate having an ethylene glycol group may include at least one member selected from the group consisting of compounds represented by the following formulas (4) to (5).

[Chemical Formula 4]

[Chemical Formula 5]

In one embodiment of the present invention, the photoinitiator may be used without limitation as long as it is used in the technical field. Type 1 type photoinitiator, in which radicals are generated by decomposition of molecules due to difference in chemical structure or molecular binding energy, and type 2 photoinitiator, which is a hydrogen reclamation type, coexisting with tertiary amines. Specific examples of the Type 1 type photoinitiator include 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyl trichloroacetophenone, diethoxyacetophenone, 2-hydroxy- 2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone and the like, benzoin, benzoin methyl Benzoin ethers such as benzoin ethyl ether and benzyldimethyl ketal, acylphosphine oxides, and titanocene compounds. Specific examples of the Type 2 type photoinitiator include benzophenone, benzoyl benzoic acid, benzoyl benzoic acid methyl ether, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3 ' Benzophenones such as methyl-4-methoxybenzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, and isopropylthioxanthone Oxanone, and the like. These may be used alone or in combination of two or more. The Type 1 type photoinitiator and the Type 2 type photoinitiator may be used alone or in combination.

The photoinitiator may be included in an amount of 0.1 to 10% by weight based on 100% by weight of the entire hard coating composition. If the amount is less than 0.1% by weight, the curing may not proceed sufficiently, and the mechanical properties and adhesiveness of the finally obtained coating film may be deteriorated. If it exceeds 10% by weight, cracking and curling due to curing shrinkage may occur.

In one embodiment of the present invention, the solvent can be used without limitation as long as it is used in the technical field. Specific examples of the solvent include alcohols such as methanol, ethanol, isopropanol, butanol and propylene glycol methoxy alcohol, ketones such as methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone and dipropyl ketone, (Such as methyl acetate, ethyl acetate, butyl acetate and propylene glycol methoxy acetate), cellosolves (methyl cellosolve, ethyl cellosolve and propyl cellosolve), hydrocarbons (normal hexane, normal heptane, benzene, toluene, Etc.). These solvents may be used alone or in combination of two or more.

The solvent may be included in an amount of 5 to 90% by weight, preferably 20 to 70% by weight based on 100% by weight of the entire hard coat composition. When the amount is less than 5% by weight, the viscosity is high and the workability is poor. When the amount is more than 90% by weight, the thickness of the coating film is difficult to adjust, and drying unevenness occurs.

The hard coating composition according to one embodiment of the present invention may further comprise inorganic nanoparticles to further improve the mechanical properties.

The inorganic nanoparticles may have an average particle diameter of 1 to 100 nm, preferably 5 to 50 nm. These inorganic nanoparticles are uniformly formed in the coating film, and can improve mechanical properties such as abrasion resistance, scratch resistance and pencil hardness. If the particle size is less than the above range, agglomeration occurs in the composition and a uniform coating film can not be formed. As a result, the above effect can not be expected. On the other hand, if the particle size exceeds the above range, The mechanical properties may be deteriorated.

The material of the inorganic nanoparticles may be a metal oxide and may be a metal oxide such as 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- in Al, Nb ₂ O _3, SnO, MgO, and combinations thereof may be used one selected, preferably the like can be used _{Al 2 O 3, SiO 2,} ZrO 2. The inorganic nanoparticles can be manufactured directly or commercially available. In the case of commercially available products, those dispersed in an organic solvent at a concentration of 10 to 80% by weight can be used.

The inorganic nanoparticles may be included in an amount of 5 to 40% by weight based on 100% by weight of the entire hard coating composition. If it is less than 5% by weight, mechanical properties such as abrasion resistance, scratch resistance and pencil hardness may not be sufficient. If it is more than 40% by weight, mechanical properties may be deteriorated and appearance may be deteriorated.

The hard coating composition according to one embodiment of the present invention may contain, in addition to the above-mentioned components, components commonly used in the art such as leveling agents, ultraviolet stabilizers, heat stabilizers, antioxidants, UV absorbers, surfactants, A lubricant, an antifouling agent, and the like may be additionally included.

The leveling agent may be used to impart smoothness and coatability of the coating film when the hard coating composition is coated. Examples of the leveling agent include BYK-323, BYK-331, BYK-333, and BYK-333 manufactured by BYK Corporation, TEGO Glide 411, TEGO Glide 415, TEGO Glide 420, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 440, TEGO Glide 412, BYK- Glide 450, TEGO Glide 455, TEGO Rad 2100, TEGO Rad 2200N, TEGO Rad 2250, TEGO Rad 2300, TEGO Rad 2500, 3M FC-4430 and FC-4432. The leveling agent is preferably used in an amount of 3 to 5% by weight based on 100% by weight of the entire hard coat composition.

The ultraviolet stabilizer is an additive added for the purpose of protecting the coating film by blocking or absorbing ultraviolet rays because the surface of the cured coating film is decomposed by continuous ultraviolet ray exposure to be discolored and crumbled. The ultraviolet stabilizer may be classified into an absorbent, a quencher, and a hindered amine light stabilizer (HALS) according to the action mechanism. Also, depending on the chemical structure, it is possible to use Phenyl salicylate (absorbent), Benzophenone (absorbent), Benzotriazole (absorber), Nickel derivative (quencher), Radical Scavenger . The ultraviolet stabilizer is not particularly limited as long as it does not significantly change the initial color of the coating film.

The heat stabilizer is a commercially applicable product, and it can be used either alone or in combination with a polyphenol as a primary heat stabilizer, a phosphite as a secondary heat stabilizer, and a lactone system.

The ultraviolet stabilizer and the heat stabilizer can be appropriately used at a level at which the ultraviolet curing property is not affected.

One embodiment of the present invention is directed to a hardcoat film formed using the hardcoat composition described above. The hard coating film according to an embodiment of the present invention is characterized in that a coating layer containing a cured product of the hard coating composition described above is formed on one side or both sides of the transparent substrate.

As the transparent substrate, any plastic film having transparency can be used. For example, cycloolefin-based derivatives having units of monomers including cycloolefins such as norbornene and polycyclic norbornene monomers, cellulose (such as diacetylcellulose, triacetylcellulose, acetylcellulose butylate, isobutylestercellulose, Propylene cellulose, butyryl cellulose and acetyl propionyl cellulose), ethylene vinyl acetate copolymer, polyester, polystyrene, polyamide, polyether imide, polyacryl, polyimide, polyether sulfone, polysulfone, polyethylene, polypropylene, Polyolefins such as polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyethersulfone, polymethylmethacrylate, polyethylene terephthalate, polybutylene terephthalate, Polyethylene naphthalate Polyesters, polycarbonates, polyurethanes, and epoxies. Unstretched, uniaxially or biaxially stretched films can be used.

The thickness of the transparent substrate is not particularly limited, but may be 8 to 1000 탆, specifically 20 to 150 탆. If the thickness of the transparent base material is less than 8 占 퐉, the strength of the film is lowered and the workability is lowered. If the thickness is more than 1000 占 퐉, the transparency is lowered or the weight of the hard coating film is increased.

The hard coating film according to one embodiment of the present invention can be produced by applying the hard coating composition of the present invention to one side or both sides of a transparent substrate and curing to form a coating layer.

The hard coating composition according to an embodiment of the present invention may be coated on a transparent substrate by appropriately using a known method such as die coater, air knife, reverse roll, spray, blade, casting, gravure, microgravure, ) Is possible.

After the hard coating composition is applied to the transparent substrate, volatiles are evaporated at a temperature of 30 to 150 ° C for 10 seconds to 1 hour, more specifically for 30 seconds to 30 minutes, And cured. The irradiation amount of the UV light may be about 0.01 to 10 J / cm 2, and more specifically, about 0.1 to 2 J / cm 2.

At this time, the thickness of the formed coating layer may be specifically 2 to 30 탆, more specifically 3 to 20 탆. When the thickness of the coating layer is within the above range, an excellent hardness effect can be obtained.

One embodiment of the present invention relates to an image display apparatus provided with the above-mentioned hard coating film. For example, the hard coating film of the present invention can be attached to an image display apparatus, particularly a window of a flexible display apparatus.

The hard coating film according to one embodiment of the present invention can be used in reflective, transmissive, semi-transmissive LCD or various driving LCDs such as TN type, STN type, OCB type, HAN type, VA type and IPS type. The hard coating film according to one embodiment of the present invention can also be used in various image display devices such as a plasma display, a field emission display, an organic EL display, an inorganic EL display, and an electronic paper.

Hereinafter, the present invention will be described more specifically with reference to Examples, Comparative Examples and Experimental Examples. It should be apparent to those skilled in the art that these examples, comparative examples and experimental examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

Production Example 1 : Acrylate group  Synthesis of Cellulose with

The natural cellulose fibers were put into a reactor, and subjected to primary decompression at 60 torr, followed by the addition of an aqueous solution of sodium hydroxide and a separating catalyst to obtain alkali cellulose. Then, the reactor was subjected to a second decompression, the reactor temperature was adjusted to 60 ° C, and the reaction was performed. Then, the temperature was raised to 80 ° C to synthesize cellulose. The low boiling point material was recovered and the resulting cellulose was filtered, and 3 mol of acrylic acid was condensed according to 1: 1 equivalent ratio to prepare cellulose having an acrylate group.

Example  1 to 5 and Comparative Example  1 to 4: Hard coating  Preparation of composition

Table 1 Composition of (meth) The polyfunctional urethane (meth) to give the acrylate and polyfunctional (meth) acrylate-based monomer mixture is a mixture of acrylates having an ethylene glycol with a cellulose, a cyclohexyl group having an acrylate (Unit: wt%).

Then, 30% by weight of the obtained acrylate-based monomer mixture, 30% by weight of silica inorganic nanoparticles Nanopol 784 (Ebonic acid, 20 nm silica sol diluted with PGMEA 50%), 5% by weight of a photoinitiator IgA cure 184 A hard coating composition was prepared by mixing 3 wt% of leveling agent BYK-333, 30 wt% of methyl ethyl ketone, and 10 wt% of toluene.

Production Example 1 (2) (3) UA-306H Formula 4 Formula 5 M-340 Example 1 25 40 35 Example 2 25 40 35 Example 3 20 40 40 Example 4 30 30 40 Example 5 30 60 10 Example 6 30 60 10 Example 7 30 10 40 20 Example 8 30 20 20 20 10 Comparative Example 1 40 15 35 10 Comparative Example 2 25 40 35 Comparative Example 3 25 40 35 Comparative Example 4 25 40 35

The compound of formula 2 (Shin-A < RTI ID = 0.0 > T &

The compound of the formula (3) (Shin-A < (R) > SOU-1290)

UA-306H (Public Corporation)

The compound of formula 4 (MWS M4004)

The compound of formula 5 (Japanese DPTA126)

M-340 (Miwon Specialty Chemical)

Experimental Example  One:

The hard coating compositions prepared in Examples and Comparative Examples were coated on one side of an optical polyimide film (Mitsubishi Gas Chemical Co., Ltd., 100 占 퐉, L-3430) so as to have a thickness of 20 占 퐉, Dried and cured at a light quantity of 350 mJ / cm 2 in a high pressure mercury lamp to produce a hard coating film.

The physical properties of the hard coating film thus prepared were measured by a method described later, and the results are shown in Tables 2 and 3 below.

(1) Pencil Hardness

The pencil hardness was measured by applying a load of 500 g using a pencil hardness tester (PHT, Korea Science and Engineering Corp.). The pencil was made using Mitsubishi products and was performed five times per pencil hardness. If two or more pieces of gas were judged to be defective.

<Evaluation Criteria>

Kiss 0: OK

Kiss 1: OK

Gas 2 or higher: NG

(2) Abrasion resistance

And scratch resistance was tested by reciprocating ten times under 1 kg / (2 cm x 2 cm) using a steel wool tester (WT-LCM100, Korea Protec Co.). Steel wool used # 0000.

<Evaluation Criteria>

S: 0 scratches

A: 1 to 10 scratches

B: 11-20 scratches

C: 21 ~ 30 scratches

D: More than 31 scratches

(3) Adhesion

11 straight lines were drawn on the coated surface of the film at intervals of 1 mm to form 100 squares, and then peel test was performed three times using a tape (CT-24, Nichii Co., Ltd.). Three 100 squares were tested and the average was recorded. The adhesion was recorded as follows.

Adhesion = n / 100

n: the number of rectangles that are not to be peeled out of the entire rectangle

100: total number of squares

Therefore, when none of them were peeled off, 100/100 was recorded.

(4) Curl

A sample cut into a square shape of A4 size (29.7 x 21.0 cm) was placed on a flat glass plate with the coated side of the film facing up, and the distance from the four-sided glass plate was measured at 25 DEG C and 50% As a measurement value.

(5) Crack resistance

In order to evaluate the cracking property, a coated film sample cut into a size of 1 cm × 10 cm was placed on a steel rod of each diameter (2φ to 10φ), and the coating layer was turned upside down to show the smallest diameter Respectively.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Pencil hardness 6H 5H 6H 5H 5H 5H 3H 5H Abrasion resistance S S S S S S A A Adhesiveness 100/100 100/100 100/100 100/100 100/100 100/100 100/100 100/100 curl 4mm 3mm 4mm 4mm 3mm 4mm 6mm 3mm Mandrell 4φ 3φ 4φ 3φ 4φ 3φ 5φ 6φ

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Pencil hardness 2B 2B 3B 3B Abrasion resistance C C C C Adhesiveness 80/100 80/100 75/100 74/100 curl 25mm 23mm 23mm 22mm Mandrell 20φ 18φ 19φ 18φ

As shown in Tables 2 and 3, the hard coating films prepared using the hard coating compositions of Examples 1 to 8 according to the present invention were excellent in hardness, scratch resistance, adhesion, curl and crack resistance. On the other hand, the hard coating films prepared using the hard coating compositions of Comparative Examples 1 to 4 showed that the hardness, scratch resistance, adhesion, curling property or crack resistance were deteriorated.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Do. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

Claims (14)

(Meth) acrylate group, a polyfunctional urethane (meth) acrylate having a cyclohexyl group, and a polyfunctional (meth) acrylate having an ethylene glycol group, a photoinitiator and a solvent. The hard coating composition according to claim 1, wherein the cellulose having a (meth) acrylate group is a compound represented by the following formula (1):
[Chemical Formula 1]

Wherein R ₁ , R ₂ and R ₃ are each independently hydrogen or a (meth) acryloyl group,
At least one of R ₁ , R ₂ and R ₃ is a (meth) acryloyl group,
n is an integer from 2 to 50; The hard coat composition according to claim 1, wherein the polyfunctional urethane (meth) acrylate having a cyclohexyl group is prepared by condensation reaction of a diisocyanate having a cyclohexyl group with a polyfunctional (meth) acrylate having a hydroxy group. 4. The hard-coating composition according to claim 3, wherein the diisocyanate having a cyclohexyl group is 1,4-cyclohexyl diisocyanate, isophorone diisocyanate or 4,4-dicyclohexylmethane diisocyanate. The hard coating composition according to claim 3, wherein the polyfunctional (meth) acrylate having a hydroxyl group is trimethylol propane di (meth) acrylate, pentaerythritol tri (meth) acrylate or dipentaerythritol penta (meth) acrylate. The hard coating composition according to claim 1, wherein the polyfunctional urethane (meth) acrylate having a cyclohexyl group is at least one selected from the group consisting of compounds represented by the following formulas (2) to (3)
(2)

(3)

The polyfunctional (meth) acrylate having an ethylene glycol group according to claim 1, wherein the polyfunctional (meth) acrylate having an ethylene glycol group is obtained by subjecting a polyhydric alcohol to an addition reaction with ethylene oxide to obtain a polyfunctional alcohol having an ethylene glycol group, &Lt; / RTI &gt; 8. The hard-coating composition according to claim 7, wherein the polyhydric alcohol is glycerol, trimethylol propane, pentaerythritol or dipentaerythritol. The polyfunctional (meth) acrylate according to claim 1, wherein the polyfunctional (meth) acrylate having an ethylene glycol group is trimethylolpropane (EO) ₃ Tri (meth) acrylate, trimethylolpropane (EO) ₆ Tri (meth) acrylate, trimethylolpropane (EO) ₉ Tri (meth) acrylate, glycerin (EO) ₃ Tri (meth) acrylate, glycerin (EO) ₆ Tri (meth) acrylate, glycerin (EO) ₉ Pentaerythritol (EO) ₄ tetra (meth) acrylate, pentaerythritol (EO) ₈ tetra (meth) acrylate, pentaerythritol (EO) ₁₂ (Meth) acrylate, dipentaerythritol (EO) ₆ hexa (meth) acrylate, dipentaerythritol (EO) ₁₂ hexa (meth) acrylate and dipentaerythritol (EO) ₁₈ hexa Lt; RTI ID = 0.0 &gt; 1, &lt; / RTI &gt; The hard coating composition according to claim 1, wherein the polyfunctional (meth) acrylate having an ethylene glycol group is at least one selected from the group consisting of compounds represented by the following formulas (4) to (5)
[Chemical Formula 4]

[Chemical Formula 5]

The hard coating composition of claim 1, further comprising inorganic nanoparticles. A hardcoat film formed using the hardcoat composition according to any one of the preceding claims. An image display apparatus comprising the hard coating film according to claim 12. A window of a flexible display device comprising a hard coating film according to claim 12.