KR102314512B1 - Composition for making hard coating layer - Google Patents

Abstract

The present invention relates to a composition for forming a hard coat layer, and more particularly, to a crosslinking agent containing a compound represented by Formula 1; Colloidal silica containing an epoxy group on the surface and having an average particle diameter of 1 to 100 nm; an epoxy siloxane resin having a weight average molecular weight of 500 to 30,000; And by including a photoinitiator, it has remarkably improved hardness, it relates to a composition for forming a hard coat layer that can form a hard coat layer with minimized curl due to excellent flexibility.

Description

Composition for forming a hard coating layer {COMPOSITION FOR MAKING HARD COATING LAYER}

The present invention relates to a composition for forming a hard coat layer.

Recently, a thin display device using a flat panel display such as a liquid crystal display or an organic light emitting diode display has received great attention. In particular, these thin display devices are implemented in the form of a touch screen panel, and are characterized by portability to various wearable devices as well as smart phones and tablet PCs. It is widely used in various smart devices.

Such portable touch screen panel-based display devices have a window cover for display protection on the display panel to protect the display panel from scratches or external impact, and in most cases, tempered glass for display is used as the window cover. Tempered glass for display is thinner than general glass, but it has high strength and is strong against scratches.

However, tempered glass has the disadvantage that it is not suitable for reducing the weight of portable devices because it is heavy in weight, and it is difficult to implement unbreakable properties because it is vulnerable to external shocks, and it is not bent over a certain level and is bendable. It is not suitable as a flexible display material having a foldable function.

Recently, various studies have been conducted on optical plastic covers that have strength or scratch resistance corresponding to tempered glass while securing flexibility and impact resistance. In general, the optical transparent plastic cover material that has more flexibility than tempered glass is polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polyacrylate (PAR), polycarbonate (PC). , polyimide (PI), and polyaramid (PA). However, in the case of these polymer plastic substrates, compared to tempered glass used as a window cover for display protection, not only exhibit insufficient physical properties in terms of hardness and scratch resistance, but also insufficient impact resistance. Therefore, various attempts are being made to supplement the physical properties required by coating the composite resin composition on these plastic substrates.

In the case of a general hard coating, a composition consisting of a resin containing a photocurable functional group such as (metha)acrylate or epoxy, a curing agent or a curing catalyst and other additives is used, and in particular, In the case of a composite resin, it can be used as a display protection window with improved hardness and scratch resistance by coating it on an optical plastic base film.

However, in the case of general (meth)acrylate or epoxy high-functional group photocurable composite resin, it is difficult to realize high hardness corresponding to tempered glass, and curl phenomenon due to shrinkage occurs greatly during curing, and flexibility is also There is a disadvantage in that it is not sufficient as a protective window substrate for application to a flexible display.

Korean Patent Application Laid-Open No. 2013-74167 discloses a plastic substrate.

Korea Patent Publication No. 2013-74167

An object of the present invention is to provide a composition capable of forming a hard coating layer having significantly improved hardness.

In addition, an object of the present invention is to provide a composition capable of forming a hard coating layer having excellent flexibility.

In addition, an object of the present invention is to provide a composition capable of forming a hard coating layer that does not cause defects due to curling.

In addition, an object of the present invention is to provide a hard coat film having the hard coat layer.

1. A crosslinking agent containing a compound represented by the following formula (1);

Colloidal silica containing an epoxy group on the surface and having an average particle diameter of 1 to 200 nm;

an epoxy siloxane resin having a weight average molecular weight of 500 to 30,000;

And a composition for forming a hard coat layer comprising a photoinitiator:

[Formula 1]

(Wherein, R ₁ and R ₂ are each independently a linear or branched alkyl group having 1 to 5 carbon atoms,

X is a single bond; carbonyl group; carbonate group; ether group; thioether group; ester group; amide group; a linear or branched alkylene group having 1 to 18 carbon atoms, an alkylidene group, or an alkoxyylene group; a cycloalkylene group or cycloalkylidene group having 1 to 6 carbon atoms; or a linking group thereof; may be).

2. The composition for forming a hard coat layer according to the above 1, wherein the crosslinking agent is at least one selected from the group consisting of compounds represented by the following Chemical Formulas 2 to 10:

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

(Wherein, R is a linear or branched alkylene group having 1 to 8 carbon atoms,

l and m are each independently an integer from 1 to 30).

3. The composition for forming a hard coat layer according to the above 1, wherein the colloidal silica containing an epoxy group on the surface is surface-treated with at least one of functional groups represented by the following Chemical Formulas 11 and 12:

[Formula 11]

[Formula 12]

(Wherein, A and B are each independently 2 to 6 straight-chain or branched alkylene groups,

"*" is a bond).

4. The composition of the above 1, wherein the siloxane resin has a polydispersity index (PDI) of 2.0 to 4.0.

5. The composition of the above 1, wherein the siloxane resin has a weight average molecular weight of 1,000 to 20,000.

6. The composition of the above 1, wherein the siloxane resin has a weight average molecular weight of 5,000 to 15,000.

7. The composition of the above 1, wherein the siloxane resin has an epoxy group equivalent of 3.0 to 6.3 mmol/g.

8. The composition for forming a hard coating layer according to the above 1, wherein the siloxane resin is polymerized by including a monomer having an aryl group in an amount of 10% by weight or less based on the total weight of the monomer.

9. The composition for forming a hard coating layer according to the above 1, wherein the siloxane resin has a UV absorption spectrum peak having a maximum absorbance at a wavelength of 200 to 250 nm.

10. The composition for forming a hard coat layer according to 1 above, wherein the crosslinking agent is included in an amount of 5 to 70% by weight of the total weight of the composition for forming a hard coat layer.

11. The composition for forming a hard coat layer according to the above 1, wherein the colloidal silica is included in an amount of 5 to 70% by weight of the total weight of the composition for forming a hard coat layer.

12. A hard coat film comprising a substrate having a hard coat layer formed of the composition for forming a hard coat layer of any one of claims 1 to 11 on at least one surface.

13. The hard coating film of the above 12, wherein the rate of change of the chromaticity b value before and after leaving the hard coat layer at 85° C. and 90% relative humidity for 1,000 hours is within 5%.

14. An image display device having the hard coating film of 12 above.

The composition of the present invention can form a hard coating layer having significantly improved hardness.

In addition, the composition of the present invention has excellent flexibility and can form a hard coating layer that can significantly suppress curing shrinkage. Accordingly, the hard coating film having a hard coating layer of the present invention can secure excellent flexibility without a separate curl suppression layer.

1 is a schematic cross-sectional view of a hard coat film having a hard coat layer formed of the composition for forming a hard coat layer of the present invention.
Figure 2 schematically shows one embodiment of performing a bending test on a hard coating film having a hard coating layer formed of the composition for forming a hard coating layer of the present invention.
Figure 3 schematically shows an embodiment of performing a bending test on a hard coating film having a hard coating layer formed of the composition for forming a hard coating layer of the present invention.

The present invention relates to a crosslinking agent containing a compound represented by Formula 1; Colloidal silica containing an epoxy group on the surface and having an average particle diameter of 1 to 200 nm; an epoxy siloxane resin having a weight average molecular weight of 500 to 30,000; And by including a photoinitiator, it has remarkably improved hardness, it relates to a composition for forming a hard coat layer that can form a hard coat layer with minimized curl due to excellent flexibility.

Hereinafter, the present invention will be described in detail.

<Composition for forming a hard coat layer>

The composition for forming a hard coat layer of the present invention includes a crosslinking agent, colloidal silica, an epoxy siloxane resin, and a photoinitiator.

crosslinking agent

The crosslinking agent according to the present invention includes a compound represented by the following Chemical Formula 1, and is a component that promotes crosslinking and allows the composition to maintain an appropriate viscosity.

[Formula 1]

In the formula, R ₁ and R ₂ are each independently a linear or branched alkyl group having 1 to 5 carbon atoms, and X is a single bond; carbonyl group; carbonate group; ether group; thioether group; ester group; amide group; a linear or branched alkylene group having 1 to 18 carbon atoms, an alkylidene group, or an alkoxyylene group; a cycloalkylene group or cycloalkylidene group having 1 to 6 carbon atoms; or a linking group thereof;

As used herein, "single bond" means a structure directly connected without other functional groups, for example, in Chemical Formula 1, two cyclic epoxy structures are directly connected, and, in the present invention, "linking group" means , means that two or more of the aforementioned substituents are connected.

In addition, in Formula 1, _{the substitution position of R 1} and R ₂ is not particularly limited, but is more preferably substituted at the 3-position based on the carbon to which the epoxy group is connected.

By having the structure of Formula 1, the above-mentioned compounds may lower the viscosity of the composition to an appropriate range while including a cyclic epoxy structure in the molecule. This decrease in viscosity not only improves the applicability of the composition, but also further improves the reactivity of the epoxy group, and it is determined that the curing reaction can be accelerated. In addition, it is determined that they can implement high hardness and discoloration prevention through reaction with the epoxy siloxane resin of the present invention.

A specific example of the compound used in the present invention may be a compound represented by the following Chemical Formulas 2 to 10, but is not limited thereto, and these may be used alone or in a mixture of two or more.

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

In the formula, R is a linear or branched alkylene group having 1 to 8 carbon atoms, and l and m are each independently an integer of 1 to 30.

In addition, the composition for forming a hard coat layer of the present invention has better hardness and flexural properties without using a separate thermosetting agent including the epoxy compound according to the present invention.

The content of the crosslinking agent is not particularly limited, and for example, may be included in an amount of 5 to 70% by weight based on the total weight of the composition for forming a hard coat layer. When the content of the epoxy compound is within the above range, it is possible to further improve the curing efficiency of the composition to form a hard coating layer having excellent flexural properties and preventing curl while having excellent hardness.

colloidal silica

The composition for forming a hard coat layer of the present invention includes an epoxy group on the surface and colloidal silica having an average particle diameter of 1 to 200 nm, thereby significantly improving hardness while maintaining excellent transparency of the hard coat layer.

The colloidal silica according to the present invention includes an epoxy group on the surface and forms a covalent bond between the epoxy group of the epoxy siloxane resin and the epoxy group of the colloidal silica, which will be described later. .

The colloidal silica according to the present invention can be used without particular limitation as long as it contains an epoxy group on the surface. For example, a colloidal solution in which colloidal silica is dispersed in a solvent or fine powder colloidal silica that does not contain a dispersion solvent contains an epoxy group. The thing surface-treated so that it may be mentioned is mentioned.

Examples of the solvent for dispersing colloidal silica include alcohols such as water, methanol, ethanol, isopropanol, and n-butanol; polyhydric alcohols and derivatives thereof such as ethylene glycol, ethylene glycol monoethyl ether, and propylene glycol monomethyl ether; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; non-polar solvents such as toluene and xylene; (meth)acrylates such as 2-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate: and other organic solvents can be used. have.

The colloidal silica having an epoxy group on the surface of the present invention may be surface-treated with at least one of functional groups represented by the following Chemical Formulas 11 and 12.

[Formula 11]

[Formula 12]

(Wherein, A and B are each independently 2 to 6 straight-chain or branched alkylene groups,

"*" is a bond).

As a method of surface-treating colloidal silica to include an epoxy group on the silica surface, a known method may be used without any particular limitation, and examples thereof include a dry method and a wet method. The dry method is a method in which silica powder is stirred at high speed using a stirrer and uniformly dispersed with a treatment agent such as a coupling agent for treatment. The wet method is a method of processing by adding a processing agent such as a coupling agent to a slurry obtained by dispersing silica in a solvent and stirring.

More specifically, a method of surface-treating colloidal silica to include an epoxy group on the surface of the silica using a silane coupling agent or the like having an epoxy group on the surface thereof is exemplified.

The silane coupling agent may be used without any particular limitation that it contains an epoxy group, and for example, may be a compound represented by the following Chemical Formula 13.

[Formula 13]

R ₃ Si(OR ₄ ) ₃

(Wherein, R ₃ is a substituent having an epoxy group, and R ₄ is an alkyl group having 1 to 4 carbon atoms).

R ₃ is not particularly limited as long as it is a substituent having an epoxy group, but preferably an alkyl group having 1 to 4 carbon atoms substituted with a glycidoxy alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms having an epoxy structure. can Specifically, for example, β-glycidoxy ethyl group, γ-glycidoxy propyl group, γ-glycidoxy butyl group, β-(3,4-epoxy cyclohexyl)ethyl group, γ-(3,4- Epoxy cyclohexyl) propyl group, β-(3,4-epoxy cycloheptyl) ethyl group, β-(3,4-epoxy cyclohexyl) propyl group, β-(3,4-epoxy cyclohexyl) butyl group, β- (3,4-epoxy cyclohexyl) pentyl group, etc. are mentioned. More preferably, a glycidoxy alkyl group having 2 to 3 carbon atoms or an alkyl group having 1 to 2 carbon atoms substituted with a cycloalkyl group having 5 to 6 carbon atoms having an epoxy structure is mentioned. Specifically, β-glycidoxy ethyl group, γ- A glycidoxy propyl group, the (beta)-(3,4-epoxy cyclohexyl) ethyl group, etc. are mentioned.

R ₃ is a glycidoxy alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms having an epoxy structure. A compound having an alkyl group having 1 to 4 carbon atoms or an epoxy group may be used alone or in combination.

As R2 in the alkoxy silicon compound which has an epoxy group of Formula (1), a (C1-C4) alkyl group is mentioned, Specifically, For example, a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl group group, s-butyl group, t-butyl group, and the like, and preferably a methyl group or an ethyl group from the viewpoint of reactivity in the following condensation reaction.

Examples of the silane coupling agent having an epoxy group represented by the formula (13) include β-glycidoxy ethyltrimethoxysilane, β-glycidoxy ethyltriethoxysilane, and γ-glycidoxy propyltrimethoxysilane. , γ-glycidoxy propyltriethoxysilane, β-(3,4-epoxy cyclohexyl) ethyltrimethoxysilane, β-(3,4-epoxy cyclohexyl) ethyltriethoxysilane, etc. are mentioned. .

These silane coupling agent compounds can be used individually or in mixture of 2 or more types.

In addition, the colloidal silica according to the present invention has an average particle diameter of 1 to 200 nm, and by including such nano-sized silica particles, the transmittance is not affected, thereby improving the hardness while maintaining excellent transparency. If the average particle diameter is less than 1 nm, the hardness improvement effect is insignificant, and if it exceeds 200 nm, it may act as a foreign material of the hard coating layer. The average particle diameter of the colloidal silica may be preferably 1 to 100 nm, and more preferably 5 to 30 nm. In the above range, it is possible to prevent a decrease in transparency while having an excellent effect of improving hardness.

The content of colloidal silica according to the present invention is not particularly limited, and may be included, for example, in an amount of 5 to 70% by weight based on the total weight of the composition for forming a hard coat layer. When the content of colloidal silica is within the above range, a hardness improvement effect is exhibited, an appropriate viscosity is maintained, an excellent coating property is exhibited, and a hard coating layer with excellent flexural properties and curling resistance can be formed.

epoxy siloxane profit

The epoxy siloxane resin of the present invention means a siloxane resin having an epoxy group, and the epoxy group may be an alicyclic epoxy group, an aliphatic epoxy group, an aromatic epoxy group, or a mixture thereof, preferably silsesquioxane having an epoxy group. .

The epoxy siloxane resin according to the present invention has a weight average molecular weight of 500 to 30,000, preferably 1,000 to 20,000, and more preferably 5,000 to 15,000 in terms of securing high hardness and fairness at the same time.

Preferably, the polydispersity index (PDI) of the epoxy siloxane resin may be 2.0 to 4.0. If the polydispersity index is less than 2.0, it is difficult to simultaneously satisfy both the hardness and ductility of the hard coating layer, and if it exceeds 4.0, the physical properties related to ductility are overexpressed.

The composition for forming a hard coat layer of the present invention can significantly improve hardness by using an epoxy siloxane resin having a weight average molecular weight and a polydispersity index in the specific range. In addition, flexibility is remarkably improved, and bending deformation can be suppressed.

The epoxy group equivalent of the epoxy siloxane resin is not particularly limited, and may be, for example, 3.0 to 6.3 mmol/g. When the epoxy group equivalent is within the above range, it is possible to significantly improve hardness by forming dense crosslinking during polymerization.

The epoxy siloxane resin according to the present invention can be prepared through hydrolysis and condensation reaction between an alkoxy silane having an epoxy group alone or an alkoxy silane having an epoxy group and a heterogeneous alkoxy silane in the presence of water.

Schemes 1 to 3 below schematically show hydrolysis and condensation reactions of alkoxysilanes in the presence of water and a catalyst.

[Scheme 1]

[Scheme 2]

[Scheme 3]

In Schemes 1 to 3, R is a linear or branched alkyl group having 1 to 7 carbon atoms, R' is a straight or branched chain alkyl group having 1 to 20 carbon atoms including an epoxy group, a cycloalkyl group having 3 to 8 carbon atoms, and carbon number 3-20 alkenyl group, C2-20 alkynyl group, C6-20 aryl group, acrylic group, methacryl group, halogen group, amino group, mercapto group, ether group, ester group, carbonyl group, carboxyl group, vinyl group, It may include at least one functional group selected from the group consisting of a nitro group, a sulfone group, and an alkyd group.

Scheme 1 above shows that the alkoxy group of the alkoxy silane as a starting material is hydrolyzed by water to form a hydroxyl group. The hydroxyl group formed through this forms a siloxane bond through a condensation reaction between the hydroxyl groups or alkoxy groups of other silanes, as shown in Scheme 2 or Scheme 3. Therefore, the weight average molecular weight and molecular weight distribution (PDI) of the finally formed siloxane compound can be controlled by controlling the reaction rate, and the reaction temperature, the amount, type, and solvent of the catalyst can be major factors.

A catalyst is used to prepare an epoxy siloxane resin having a weight average molecular weight of 500 to 30,000 and a polydispersity index of 2.0 to 4.0 using the above reaction formula. Examples of the usable catalyst include acid catalysts such as hydrochloric acid, acetic acid, hydrogen fluoride, nitric acid, sulfuric acid chlorosulfonic acid, iodic acid, and phyllophosphoric acid; base catalysts such as ammonia, potassium hydroxide, sodium hydroxide, barium hydroxide, imidazole, n-butylamine, di-n-butylamine, tri-n-butylamine, ammonium perchlorate, and tetramethyl-ammonium hydroxide; and ion exchange resins such as Amberite IRA-400 and IRA-67, and may also be selected from the group consisting of combinations thereof.

The amount of the catalyst is not particularly limited, but in the case of an acid catalyst and a base catalyst, about 0.0001 to about 0.01 parts by weight may be added based on about 100 parts by weight of the alkoxy silane, and in the case of an ion exchange resin, about 1 to about 100 parts by weight of the alkoxy silane to about 10 parts by weight may be added, but may not be limited thereto.

The hydrolysis and condensation reaction may be carried out by stirring at room temperature for about 12 hours to about 7 days, but in order to promote the reaction, stirring may be performed at about 60° C. to about 100° C. for about 2 hours to about 72 hours. , which may not be limited thereto.

As can be seen in Schemes 1 to 3, when the reaction occurs, alcohol and water, which are by-products, are generated. By removing these, a reverse reaction can be reduced and a forward reaction can be induced, thereby controlling the reaction rate. In addition, when the reaction is completed, alcohol and water remaining in the siloxane resin may be removed by applying a condition of about 60° C. to about 100° C. under reduced pressure for about 10 minutes to about 60 minutes, but may not be limited thereto.

The alkoxy silane having an epoxy group used in the preparation of the epoxy siloxane resin according to an embodiment of the present invention may be exemplified by the following Chemical Formula 14:

[Formula 14]

R ¹ _n Si(OR ² ) _4-n

(Wherein, R ¹ is a linear or branched alkyl group having 1 to 6 carbon atoms substituted with an epoxycycloalkyl group having 3 to 6 carbon atoms or an oxiranyl group, and may be interrupted by oxygen,

R ² is a straight-chain or branched alkyl group having 1 to 7 carbon atoms,

n is an integer from 1 to 3).

The alkoxysilane represented by Formula 14 is not particularly limited, and for example, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane , 3-glycidoxypropyl trimethoxysilane, and the like. These can be used individually or in mixture of 2 or more types.

In one embodiment of the present application, the epoxy siloxane resin may be prepared by an alkoxysilane having an epoxy group alone, but also may be prepared through hydrolysis and condensation reaction between an alkoxysilane having an epoxy group and a heterogeneous alkoxysilane, but, may not be limited.

The heterogeneous alkoxy silane may be used by selecting one or more types from the alkoxy silanes represented by the following formula (15):

[Formula 15]

R ³ _m Si(OR ⁴ ) _4-m ;

(Wherein, R ³ is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an acrylic group, methacryl group It may include at least one functional group selected from the group consisting of a group, a halogen group, an amino group, a mercapto group, an ether group, an ester group, a carbonyl group, a carboxyl group, a vinyl group, a nitro group, a sulfone group and an alkyd group,

R ⁴ is a straight-chain or branched alkyl group having 1 to 7 carbon atoms, and m is an integer of 0 to 3).

The alkoxysilane represented by Formula 15 is not particularly limited, and for example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, dimethyldimethoxy Silane, dimethyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, triphenylmethoxysilane, triphenylethoxysilane, ethyltrie Toxysilane, propylethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltrimethoxy silane, N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane, N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltripropoxysilane, 3-acryloxypropylmethylbis(trimethoxy)silane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropyltripropoxysilane, 3-(meth)acryl Oxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropyltripropoxysilane, N-(aminoethyl-3-aminopropyl)trimethoxysilane, N -(2-Aminoethyl-3-aminopropyl)triethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, chloropropyltrimethoxysilane, chloropropyltriethoxysilane, hepta Decafluordecyltrimethoxysilane etc. are mentioned. These can be used individually or in mixture of 2 or more types.

Preferably, the epoxy siloxane resin according to the present invention may be polymerized by including a small amount of a monomer having an aryl group. For example, the monomer having an aryl group may be polymerized by including 10% by weight or less of the total weight of the monomer. If the content of the monomer having an aryl group is more than 10% by weight based on the total weight of the monomer, yellowing of the hard coating layer may occur.

The epoxy siloxane resin according to the present invention may be polymerized without including a monomer having an aryl group in a small amount, and most preferably, a monomer having an aryl group in order to suppress yellowing.

In addition, the epoxy siloxane resin may have a UV absorption spectrum peak exhibiting a maximum absorbance at a wavelength of 200 to 250 nm. When the maximum absorbance is shown at the above wavelength, yellowing of the hard coating layer prepared with the composition of the present invention can be minimized.

The content of the epoxy siloxane resin is not particularly limited, and for example, may be included in an amount of 5 to 70% by weight based on the total weight of the composition for forming a hard coat layer. When the content of the epoxy siloxane resin is within the above range, it is possible to exhibit the effect of improving hardness and form a hard coating layer having excellent bending properties and preventing curl.

photoinitiator

As the photoinitiator, a photocationic initiator capable of initiating polymerization of the epoxy siloxane resin and the epoxy-based monomer may be used.

The photocationic initiator may be, for example, an onium salt and/or an organometallic salt, but is not limited thereto. For example, diaryliodonium salts, triarylsulfonium salts, aryldiazonium salts, iron-arene complexes and the like can be used. These can be used individually or in mixture of 2 or more types.

The content of the photoinitiator is not particularly limited, and for example, may be included in an amount of 0.1 to 20% by weight of the total weight of the composition for forming a hard coating layer. When the content of the photoinitiator is within the above range, it is possible to maintain excellent curing efficiency of the composition and prevent deterioration of physical properties due to residual components after curing.

The composition for forming a hard coat layer of the present invention may further include a solvent.

The solvent according to the present invention is not particularly limited, and solvents known in the art may be used, for example, alcohol-based (methanol, ethanol, isopropanol, butanol, methyl cellulose, ethyl sol-sorb, etc.), ketone-based (methyl Ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), hexane type (hexane, heptane, octane, etc.), benzene type (benzene, toluene, xylene, etc.) can be used These can be used individually or in mixture of 2 or more types.

The content of the solvent according to the present invention is not particularly limited, and for example, may be included in an amount of 10 to 60% by weight of the total weight of the composition for forming a hard coat layer. When the content of the solvent is within the above range, it is possible to maintain an appropriate viscosity, so that the workability is excellent, the thickness control of the coating film is easy, and the process speed can be improved.

If necessary, the composition for forming a hard coat layer of the present invention may further include a lubricant to improve winding efficiency, blocking resistance, abrasion resistance, and scratch resistance.

The type of lubricant according to the present invention is not particularly limited, and examples thereof include waxes such as polyethylene wax, paraffin wax, synthetic wax or montan wax; synthetic resins such as silicone-based resins and fluorine-based resins; and the like. These can be used individually or in mixture of 2 or more types.

The content of the lubricant according to the present invention is not particularly limited, and for example, may be included in an amount of 0.1 to 5% by weight based on the total weight of the composition for forming a hard coat layer. When the content is within the above range, while imparting excellent blocking resistance, friction resistance and scratch resistance, the transparency can also be excellently maintained.

In addition, if necessary, additives such as antioxidants, UV absorbers, light stabilizers, thermal polymerization inhibitors, leveling agents, surfactants, lubricants, and antifouling agents may be further included.

<Hard coating film>

In addition, the present invention provides a hard coating film 100 comprising a substrate 110 having a hard coating layer 120 formed of the composition for forming a hard coating layer on at least one surface.

The substrate 110 according to the present invention preferably has excellent transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, etc., for example, a polyester-based resin such as polyethylene terephthalate, polyethylene isophthalate, and polybutylene terephthalate. ; Cellulose resins, such as a diacetyl cellulose and a triacetyl cellulose; polycarbonate-based resin; acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; styrenic resins such as polystyrene acrylonitrile-styrene copolymer; polyolefin-based resins such as polyethylene, polypropylene, polyolefin-based resins having a cyclo-based or norbornene structure, and ethylenepropylene copolymers; polyimide-based resin; polyaramid-based resin; polyether sulfone-based resin; It may be a substrate made of a sulfone-based resin or the like. These resins can be used individually or in mixture of 2 or more types.

The thickness of the substrate 110 is not particularly limited, and may be, for example, 10 to 250 μm.

The hard coat layer 120 is formed by applying and curing the composition for forming the hard coat layer, and the application is performed by a known method such as a die coater, air knife, reverse roll, spray, blade, casting, gravure, spin coating, etc. can be

In the case of curing, the method is not particularly limited, and for example, photocuring or thermal curing may be performed alone, or thermal curing after photocuring, photocuring after thermal curing, or the like may be used.

The thickness of the hard coating layer 120 is not particularly limited, and may be, for example, 10 to 100 μm. When the thickness is within the above range, the curling phenomenon hardly occurs and the hard coating layer 120 having excellent hardness can be obtained.

The hard coating layer 120 according to the present invention is formed of the composition for forming the hard coating layer and has significantly improved hardness. The hardness may vary depending on the content, type, etc. of the individual compositions, but the pencil hardness may be 5H or more, and may be 9H or more at the maximum when each of the above-described compositions is used in combination in a desired amount.

In addition, the flexibility is remarkably improved, and the bending deformation is very small.

In addition, even when exposed to high temperature and high humidity conditions for a long time, it is possible to minimize the occurrence of yellowing. For example, the rate of change of the chromaticity b value before and after standing for 1,000 hours in a moist heat resistant condition of 85° C. and 90% relative humidity may be within 5%.

The hard coating film 100 of the present invention has a very high surface hardness and at the same time has a hard coating layer 120 having excellent flexibility, and is lighter than tempered glass and has excellent impact resistance, so it is used as a window substrate on the outermost surface of a display panel. It can be used preferably.

In addition, the present invention provides an image display device having the hard coating film (100).

The hard coating film 100 may be used as an outermost window substrate of an image display device, and the image display device is a conventional liquid crystal display device, an electroluminescence display device, a plasma display device, a field emission display device, etc. Various image display devices. can

Hereinafter, examples will be given to describe the present invention in detail.

manufacturing example One

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.64g: 2.70g (0.1mol: 0.15mol) It was placed in a 250 mL 2 neck flask. Then, 0.1 mL of tetramethylammonium hydroxide as a catalyst and 100 mL of methyl ethyl ketone (MEK) were added to the mixture, followed by stirring at 60° C. for 36 hours. Then, it was filtered using a 0.45 ㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 2

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI) and water (H ₂ O, Sigma-Aldrich) in a ratio of 24.64g: 2.70g (0.1mol: 0.15mol) The mixture was put into a 250 mL 2 neck flask. After that, 0.1 mL of tetramethylammonium hydroxide was added to the mixture, a catalyst and 50 mL of MEK, and the mixture was stirred at 70° C. for 24 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 3

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.64g: 2.70g (0.1mol: 0.15mol) It was placed in a 100 mL 2 neck flask. Then, 0.1 mL of tetramethylammonium hydroxide was added to the mixture as a catalyst, and the mixture was stirred at 80° C. for 24 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 4

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.64g: 2.70g (0.1mol: 0.15mol) It was placed in a 100 mL 2 neck flask. Then, 0.1 mL of tetramethylammonium hydroxide was added to the mixture and 100 mL of MEK was added, followed by stirring at 60° C. for 36 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 5

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.64g: 2.70g (0.1mol: 0.15mol) It was placed in a 100 mL 2 neck flask. Then, 1.0 mL of tetramethylammonium hydroxide was added to the mixture as a catalyst, and the mixture was stirred at 70° C. for 36 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 6

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.64g: 2.70g (0.1mol: 0.15mol) It was placed in a 100 mL 2 neck flask. Then, 0.2 mL of tetramethylammonium hydroxide was added to the mixture and 50 mL of MEK was added, followed by stirring at 60° C. for 36 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 7

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI), diphenylsilanediol (DPSD, TCI), and water (H ₂ O, Sigma-Aldrich) 24.64g: 2.164 g: 2.7 g (0.1 mol: 0.01 mol: 0.15 mol) was mixed in a ratio and put into a 100 mL 2 neck flask. Then, 0.2 mL of tetramethylammonium hydroxide was added to the mixture and 50 mL of MEK was added, followed by stirring at 60° C. for 36 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 8

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI), diphenylsilanediol (DPSD, TCI), and water (H ₂ O, Sigma-Aldrich) 24.64g: 3.246 g: 2.7 g (0.1 mol: 0.015 mol: 0.15 mol) was mixed in a ratio and put into a 100 mL 2 neck flask. Then, 0.2 mL of tetramethylammonium hydroxide was added to the mixture and 50 mL of MEK was added, followed by stirring at 60° C. for 36 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 9

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI): 24.64g of diphenylsilanediol (DPSD, TCI), water (H ₂ O, Sigma-Aldrich): 10.82 g: 2.7 g (0.1 mol: 0.05 mol: 0.15 mol) was mixed in a ratio and put in a 100 mL 2 neck flask. Then, 0.2 mL of tetramethylammonium hydroxide was added to the mixture and 50 mL of MEK was added, followed by stirring at 60° C. for 36 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 10

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.64g: 2.70g (0.1mol: 0.15mol) It was placed in a 100 mL 2 neck flask. Then, 0.05 mL of tetramethylammonium hydroxide was added to the mixture and 50 mL of MEK was added, followed by stirring at 70° C. for 36 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 11

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.64g: 2.70g (0.1mol: 0.15mol) It was placed in a 100 mL 2 neck flask. Then, 0.5 mL of tetramethylammonium hydroxide was added to the mixture and 50 mL of MEK was added, followed by stirring at 70° C. for 24 hours. Then, it was filtered using a 0.45㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 12

2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI), phenyltrimethoxysilane (PTMS, Sigma-Aldrich), and water (H ₂ O, Sigma-Aldrich) were mixed with 11.09 g: 13.22 g: 2.70 g (0.045 mol: 0.055 mol: 0.15 mol) was mixed in the ratio of the mixture was put into a 250 mL 2 neck flask. Then, 0.1 mL of tetramethylammonium hydroxide was added to the mixture, a catalyst and 50 mL of MEK, and the mixture was stirred at 80° C. for 24 hours. Then, it was filtered using a 0.45 ㎛ Teflon filter (Teflon filter) to obtain an alicyclic epoxy silsesquioxane resin. The molecular weight of the alicyclic epoxy silsesquioxane resin was measured using gel permeation chromatography (GPC).

manufacturing example 13

90 wt% of MEK-ST (Nissan Chemical Industry Co., Ltd., organo silica sol (solid content 30%)) and 10 wt% of 3-glycidoxypropyltrimethoxysilane were added to a round-bottom flask equipped with a stirrer and cooling tube. It was stirred at room temperature for 6 hours to obtain colloidal silica having an average particle diameter of 12 nm including an epoxy group on the surface.

manufacturing example 14

MEK-ST (Nissan Chemical Industry Co., Ltd., organo silica sol (solid content 30%)) 90% by weight, 2-(3,4-epoxycyclohexyl)ethyl trime in a round-bottom flask equipped with a stirrer and cooling tube 10 wt% of toxysilane was stirred at room temperature for 6 hours to obtain colloidal silica having an average particle diameter of 12 nm including an epoxy group on the surface.

division Mn Mw PDI (Mw/Mn) Epoxy group equivalent (mmol/g) Maximum UV absorption wavelength (nm) Preparation Example 1 650 1980 3.05 6.3 220nm Preparation 2 2300 5500 2.39 6.3 217nm Preparation 3 3645 11745 3.22 6.3 220nm Preparation 4 972 2430 2.50 6.3 225nm Preparation 5 4210 8700 2.07 6.3 223nm Preparation 6 1740 6800 3.91 6.3 220nm Preparation 7 1771 5500 3.11 5.2 245nm Preparation 8 3560 8560 2.40 4.8 270nm Preparation 9 2590 10500 4.05 6.3 227nm Preparation 10 2804 5206 1.86 6.3 224nm Preparation 11 1210 5320 4.40 6.3 220nm Preparation 12 1700 5000 2.94 2.84 219nm

Example and comparative example

A composition for forming a hard coat layer having the composition and content shown in Table 2 was prepared.

division Siloxane resin photoinitiator crosslinking agent colloidal silica menstruum ingredient weight% ingredient weight% ingredient weight% ingredient weight% ingredient weight% Example 1 Preparation Example 1 20 A 5 B-1 20 C-1 30 D 25 Example 2 Preparation 2 20 A 5 B-1 20 C-2 30 D 25 Example 3 Preparation 3 20 A 5 B-1 20 C-1 30 D 25 Example 4 Preparation 4 20 A 5 B-2 20 C-1 30 D 25 Example 5 Preparation 5 20 A 5 B-1 20 C-2 30 D 25 Example 6 Preparation 6 20 A 5 B-2 20 C-2 30 D 25 Example 7 Preparation 7 20 A 5 B-1 20 C-1 30 D 25 Example 8 Preparation 8 20 A 5 B-1 20 C-1 35 D 25 Example 9 Preparation 9 20 A 5 B-1 20 C-1 5 D 25 Example 10 Preparation 10 20 A 5 B-1 20 C-1 30 D 25 Example 11 Preparation 11 20 A 5 B-1 20 C-1 30 D 25 Example 12 Preparation 12 20 A 5 B-1 20 C-1 30 D 25 Example 13 Preparation 3 8 A One B-1 75 C-1 8 D 8 Example 14 Preparation 3 8 A One B-1 8 C-1 75 D 8 Comparative Example 1 Preparation Example 1 20 A 5 B-3 20 C-1 30 D 25 Comparative Example 2 Preparation Example 1 20 A 5 B-1 20 C-3 30 D 25 Comparative Example 3 Preparation 2 20 A 5 - - C-1 30 D 25 Comparative Example 4 Preparation 3 20 A 5 B-1 20 - - D 25

B-3:

C-1: 제조예 13의 콜로이드 실리카
C-2: 제조예 14의 콜로이드 실리카
C-3: 표면 처리되지 않은 평균 입경 12㎚의 콜로이드 실리카(아엘로질社)
D: 메틸에틸케톤A: (4-methylphenyl) [4- (2-methylpropyl) phenyl] iodonium hexafluorophosphate
B-1: compound of formula 2
B-2:

B-3:

C-1: Colloidal silica of Preparation Example 13
C-2: colloidal silica of Preparation 14
C-3: Colloidal silica with an average particle diameter of 12 nm without surface treatment (Aelozil)
D: methyl ethyl ketone

Experimental example

The composition for forming the hard coating layer of Examples and Comparative Examples was applied to a 125um PET film (SKC) using a Meyer bar, cured at 100°C for 10 minutes, and UV-irradiated at 1J/cm2 using a high-pressure mercury lamp, followed by UV irradiation at 150°C for 10 minutes. After curing for minutes, a hard coating layer having a thickness of 50 μm was obtained.

(1) Curl due to curing shrinkage ( Curl ) measurement

After sampling the samples prepared in the Examples and Comparative Examples to a size of 10 mm * 10 mm, the hard coating layer is placed on the upper surface on a flat glass plate, and the maximum value of the distance at which one side of each corner is spaced apart from the plane is 25 ℃, 55 Measured in % relative humidity.

(2) Measurement of pencil hardness

The hardness of the hard coating layer was measured using a pencil hardness meter according to JIS K5600.

(3) flexibility evaluation

As shown in FIG. 2, the hard coating film prepared in the experimental example was _{wound 180° on a cylinder with a bottom radius of R 1} so that the hard coating layer was on the inside, and then returned to the original position. _{The minimum R 1 in} which no flexural deformation was observed was recorded.

And, as shown in FIG. 3 , it was wound at 180° so that the hard coating layer came to the outside of the cylinder of the _{base radius R 2 , and then returned to the original position, and then the minimum R 2 in} which no bending deformation was observed was recorded.

(4) UV absorption peak

The absorbance of each UV wavelength band of the silsesquioxane resin prepared in Preparation Example was measured using a UV-Vis spectrometer (Shimadzu).

(5) yellowing Whether the phenomenon occurs

Samples prepared in Examples and Comparative Examples were sampled in a size of 10 mm * 10 mm and left for 1,000 hours in a high-temperature, high-humidity chamber at 85 ° C. and 90% relative humidity. was measured using

division curl amount
(mm) pencil hardness Flexibility (mm) Chromaticity b value change rate (%) R ₁ R ₂ Example 1 -2 9H 8 17 1.3 Example 2 -4 9H 6 15 2.1 Example 3 -5 9H 9 19 1.7 Example 4 -3 9H 6 14 1.6 Example 5 -5 9H 10 20 2.3 Example 6 -4 9H 7 15 2.0 Example 7 +4 8H 12 29 4.1 Example 8 +5 8H 14 31 4.7 Example 9 -10 8H 16 38 2.3 Example 10 -7 7H 14 33 2.1 Example 11 -8 7H 12 20 2.1 Example 12 +6 7H 15 24 7.2 Example 13 -13 9H 14 35 1.9 Example 14 -10 9H 15 27 2.6 Comparative Example 1 +46 4H 20 41 2.3 Comparative Example 2 -35 4H 22 45 1.8 Comparative Example 3 -52 3H 26 51 2.0 Comparative Example 4 -63 3H 38 73 2.1

Referring to Table 3, the hard coating film having a hard coating layer prepared from the compositions of Examples 1 to 14 exhibited excellent curling properties, hardness and flexibility. In addition, it was confirmed that the yellowing phenomenon was minimized because the change rate of the chromaticity b value was small even after heat-and-moisture treatment.

However, the hard coating film having a hard coating layer prepared from the compositions of Comparative Examples 1 to 6 was shrinkage after curing, and curling occurred, and hardness and flexibility were remarkably deteriorated.

100: hard coating film 110: substrate
120: hard coating layer

Claims (14)

a crosslinking agent containing a compound represented by the formula (1);
Colloidal silica containing an epoxy group on the surface and having an average particle diameter of 1 to 200 nm;
an epoxy siloxane resin having a weight average molecular weight of 500 to 30,000 and a polydispersity index (PDI) of 2.0 to 4.0; and
a photoinitiator;
The siloxane resin has an epoxy group equivalent of 3.0 to 6.3 mmol/g,
After curing, the composition for forming a hard coat layer has a curl amount of -5 mm to +5 mm at 25° C. and 55% relative humidity after curing, the composition for forming a hard coat layer:
[Formula 1]

(Wherein, R ₁ and R ₂ are each independently a linear or branched alkyl group having 1 to 5 carbon atoms,
X is a single bond; carbonyl group; carbonate group; ether group; ester group; a linear or branched alkylene group having 1 to 18 carbon atoms, or an alkoxyylene group; or a linking group thereof; may be).
The composition for forming a hard coating layer according to claim 1, wherein the crosslinking agent is at least one selected from the group consisting of compounds represented by the following Chemical Formulas 2 to 5, Chemical Formula 7, Chemical Formula 9 and Chemical Formula 10:
[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 7]

[Formula 9]

[Formula 10]

(Wherein, R is a linear or branched alkylene group having 1 to 8 carbon atoms,
l and m are each independently an integer from 1 to 30).
The composition for forming a hard coating layer according to claim 1, wherein the colloidal silica having an epoxy group on the surface is surface-treated with at least one of functional groups represented by the following Chemical Formulas 11 and 12:
[Formula 11]

[Formula 12]

(Wherein, A and B are each independently 2 to 6 straight-chain or branched alkylene groups,
"*" is a bond).
delete The composition of claim 1, wherein the siloxane resin has a weight average molecular weight of 1,000 to 20,000.
The composition of claim 1, wherein the siloxane resin has a weight average molecular weight of 5,000 to 15,000.
delete The composition for forming a hard coat layer according to claim 1, wherein the siloxane resin is polymerized by including a monomer having an aryl group in an amount of 10% by weight or less based on the total weight of the monomer.
The composition for forming a hard coating layer according to claim 1, wherein the siloxane resin has a UV absorption spectrum peak having a maximum absorbance at a wavelength of 200 to 250 nm.
The composition for forming a hard coat layer according to claim 1, wherein the crosslinking agent is included in an amount of 5 to 70% by weight of the total weight of the composition for forming a hard coat layer.
The composition for forming a hard coat layer according to claim 1, wherein the colloidal silica is included in an amount of 5 to 70% by weight of the total weight of the composition for forming a hard coat layer.
A hard coating film comprising a substrate having a hard coat layer formed of the composition for forming a hard coat layer of any one of claims 1 to 3, 5, 6, and 8 to 11 on at least one surface.
The method according to claim 12, The hard coating layer is 85 ℃, 90% relative humidity conditions before and after 1,000 hours of chromaticity b value change rate of less than 5%, the hard coating film.
An image display device having the hard coating film of claim 12 .

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