KR20170103391A - Hard coating composition and hard coating film formed therefrom - Google Patents

Abstract

The present invention relates to a hard coating composition and a hard coating film using the same, and more particularly, to a hard coating composition containing an antioxidant compound represented by chemical formula 1 or 2, an acrylate compound, and a photoinitiator; and to a hard coat film formed therefrom.

Description

TECHNICAL FIELD [0001] The present invention relates to a hard coating composition and a hard coating film formed therefrom. BACKGROUND OF THE INVENTION < RTI ID = 0.0 >

The present invention relates to a hard coating composition capable of forming a hard coating film protecting the display of an image display apparatus and a hard coating film formed therefrom.

Mobile devices that can bend or fold beyond curved smartphones that are simply curved in the near future will appear on the market. This is a product that adopts a flexible display type which is one step advanced from the commercialized curved display. Flexible display technology can be simply bent bendable in a bent curved, foldable in a foldable form, and finally rolled or rolled into a foldable form. It is expected to evolve into a stretchable form that can be increased or decreased.

Foldable display is a display that can be folded in half like a book or notebook, and various companies have proposed various technologies and patents. When the display is designed to be foldable, it can be used as a tablet when it is folded, and it can be used as a smartphone if it is folded. It can be used as a single product of different size. Devices can be doubled if they can be folded and carried.

Normally, in the case of a display, a cover window made of a glass material is provided at the outermost side to protect the display. However, in the case of glass, it is not applicable to a foldable display, and a hard hard coating film having high hardness and abrasion resistance to replace glass is used.

In order to ensure hardness of the glass level, it is necessary to increase the thickness of the hard coat layer in the hard coat film. As the thickness of the hard coat layer increases, the surface hardness can be increased. However, the hard coat layer is hardened and shrunk, Crack (or cracking) or peeling of the coating layer tends to occur, so that it is not easy to apply it practically.

Korean Patent Laid-Open Publication No. 2014-0016650 relates to a colored photosensitive resin composition comprising (A) at least one pigment and at least one dye, wherein at least one of the pigment or dye is a blue-based colorant, (B) An alkali-soluble resin having an acid value of 30 to 150 mgKOH / g, (C) a photopolymerizable compound, (D) a photopolymerization initiator comprising a photopolymerization initiator represented by the following general formula (1), (E) An antioxidant having both an antioxidant functional group and a phenolic antioxidant functional group and a sulfur-based antioxidant functional group at the same time, and (F) a solvent. However, It is hard to apply and flexibility.

Korean Patent Publication No. 2012-0080143 relates to a curable composition comprising an alkenyl group bonded to a silicon atom and containing siloxane units of the general formulas 1 to 3, wherein the number of mols of the siloxane unit of the general formula (1) And the number of moles of the siloxane unit represented by the formula (3) is 0.005 to 0.05 times the total number of moles of the siloxane units represented by the formula (1) and (2), and a linear polysiloxane having a hydrogen atom bonded to the silicon atom The content of the curable composition containing a silicon compound is disclosed. However, when the coating is performed using the curable composition, a phenomenon that the composition is oxidized after coating occurs causes a problem that the YI (Yellowness Index) have.

Therefore, there is a demand for a hardcoat film capable of preventing oxidation and reducing the YI value, as well as flexibility and hardness.

Korean Patent Publication No. 2014-0016650 (Feb. Korea Open Patent No. 2012-0080143 (July 16, 2012)

It is an object of the present invention to provide a hard coating composition capable of preventing oxidation or reducing the YI value.

It is also an object of the present invention to provide a hardcoat composition capable of producing a hardcoat film excellent in hardness and flexibility.

It is also an object of the present invention to provide a hard coat film having low oxidation resistance or low YI value.

Another object of the present invention is to provide a hard coating film excellent in hardness and flexibility.

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.

In order to accomplish the above object, the present invention provides a hard coating composition comprising: an antioxidant compound represented by Formula 1 or 2; Acrylate compounds; And a photoinitiator.

[Chemical Formula 1]

(2)

In formulas (1) and (2)

R1 to R28 each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms,

Each of L1 to L5 independently represents a linear or branched alkylene having 1 to 10 carbon atoms.

The present invention also provides a hardcoat film comprising a cured product of the hardcoat composition described above.

Further, the present invention provides an image display device provided with the above-mentioned hard coating film.

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

The hard coating composition according to the present invention can provide a hard coating composition capable of preventing oxidation or reducing the YI value because it contains a specific antioxidant compound.

Further, by using the hard coating composition described above, it is possible to produce a hard coating film excellent in hardness and flexibility and low in oxidation resistance or YI value, and thus can be applied to a window of a flexible display device as well as an image display device .

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  Composition>

An embodiment of the present invention is an antioxidant compound represented by the following general formula (1) or (2): Acrylate compounds; And a hard coat composition comprising a photoinitiator.

The hard coating composition of the present invention may further contain additives and solvents such as inorganic nanoparticles having a reactive functional group.

The total solids content of the hard coating composition in the present invention means the total content of the remaining components excluding the solvent from the hard coating composition.

For example, when the inorganic nanoparticles are dispersed, only the inorganic nanoparticles are considered in the total solid content of the hard coating composition.

Antioxidant compound

The hard coating composition of the present invention comprises an antioxidant compound represented by the following general formula (1) or (2).

[Chemical Formula 1]

(2)

In formulas (1) and (2)

R1 to R28 each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms,

Each of L1 to L5 independently represents a linear or branched alkylene having 1 to 10 carbon atoms.

In the present invention, the number of carbon atoms of the alkyl group may be 1 to 10, preferably 1 to 6. Specific examples include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec- N-pentyl, 3-dimethylbutyl, 2-ethylbutyl, heptyl, n-hexyl, N-octyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethyl Heptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl and the like.

In the present invention, the content of the above-mentioned "alkyl group" is applicable except that the alkylene is divalent.

In general, phenolic antioxidants are known to act as active radical scavengers to prevent the deterioration of the resin during curing of the coating composition. The P-type antioxidant plays a role of preventing the discoloration of the resin after curing as a release of the peroxide, and the S-type antioxidant is known to decompose and neutralize the peroxide generated by the natural oxidation of the crosslinked product. And to prevent discoloration.

The composition for hard coating according to the present invention has an advantage of being more excellent in preventing discoloration since it contains an antioxidant compound having a phenolic functional group and a P-based or S-based functional group at the same time.

The formula 1 may be represented by the following formula 1-1, but is not limited thereto.

[Formula 1-1]

The formula (2) may be represented by the following formula (2-1), but is not limited thereto.

[Formula 2-1]

The antioxidant compound represented by Chemical Formula 1 or Chemical Formula 2 may be prepared and used, and commercially available products may be used, but the present invention is not limited thereto.

Examples of commercially available products of the antioxidant compound represented by the above formula (1), that is, antioxidant compounds having both phenolic and P-based functional groups include Irganox 1425 (BASF) and Sumilizer GP (Sumitomo) (Such as Irganox 1035, Irganox 1081, and Irganox 1726 (BASF)) as antioxidant compounds having antioxidant properties, that is, antioxidant compounds having both a phenolic functional group and an S functional group at the same time.

In one embodiment of the present invention, the antioxidant is contained in an amount of 0.05 to 100 parts by weight, preferably 1 to 80 parts by weight, more preferably 2 to 50 parts by weight, based on 100 parts by weight of the photoinitiator, . If the antioxidant compound is contained in an amount of less than 0.05 part by weight based on 100 parts by weight of the photoinitiator, the effect of preventing discoloration may not be sufficient. If the antioxidant compound is used in an amount exceeding 100 parts by weight, sufficient cured coating film may be somewhat difficult to secure.

Acrylate series  compound

The hard coat composition of the present invention comprises an acrylate-based compound.

In still another embodiment of the present invention, the acrylate compound is selected from the group consisting of a urethane (meth) acrylate compound containing a cycloalkyl moiety and a polyfunctional (meth) acrylate compound containing an oxyethylene group (Meth) acrylate-based compound containing the cycloalkyl moiety and a polyfunctional (meth) acrylate-based compound containing the oxyethylene group in view of flexibility and hardness Are preferably included.

(One) Cycloalkyl  Containing part Urethane (meth) acrylate series  compound

When the urethane (meth) acrylate compound is contained in the hard coating composition, sufficient hardness and scratch resistance can be secured.

The hard coating composition may comprise a urethane (meth) acrylate based compound comprising a cycloalkyl moiety. The term "including a cycloalkyl moiety" may refer to a case where a part of the compound includes a cycloalkyl moiety. For example, the cycloalkyl moiety may be a monovalent cycloalkyl group, or a divalent cycloalkylene group, and the cycloalkyl moiety may be mono- or polysubstituted or unsubstituted. When the cycloalkyl moiety is substituted, the substituent may be an alkyl group such as methyl, ethyl, propyl, or a halogen group such as fluoro, chloro or bromo. The urethane (meth) acrylate resin containing the cycloalkyl moiety may be a polyfunctional compound.

The cycloalkyl group is not particularly limited, but preferably has 3 to 40 carbon atoms. Specific examples include cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, and the like, but are not limited thereto.

The cycloalkylene group is not particularly limited, but preferably has 3 to 40 carbon atoms. Specifically, the cycloalkylene group may be a cyclic alkylene group such as cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene, methylcyclopentylene, dimethylcyclopentylene, methylcyclohexylene, dimethylcyclohexylene , Cyclohexylene, and the description of the above-mentioned cycloalkyl group can be applied, except that the cycloalkylene group is a divalent group.

When the hard coating composition comprises a urethane (meth) acrylate-based compound containing the cycloalkyl moiety, it is possible to produce a hard coat film having improved mechanical properties. Specifically, when a hard coat film containing a hard coat layer containing a urethane (meth) acrylate compound containing the cycloalkyl moiety is prepared, it is possible to produce a hard coat film having an improved hardness.

The urethane (meth) acrylate compound containing the cycloalkyl moiety may be prepared by condensation reaction of a diisocyanate having a cycloalkyl group with a polyfunctional (meth) acrylate having a hydroxy group, but is not limited thereto.

The diisocyanate may include at least one of the group consisting of 1,4-cyclohexyl diisocyanate, isophorone diisocyanate, and 4,4-dicyclohexylmethane diisocyanate.

The polyfunctional (meth) acrylate containing the hydroxy group may include at least one of trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate .

The cycloalkyl group may be a cyclohexyl group. That is, the urethane (meth) acrylate compound containing the cycloalkyl moiety of the present invention may be a urethane (meth) acrylate compound containing a cyclohexyl group.

The urethane (meth) acrylate compound containing the cycloalkyl moiety may be represented by the following general formula (3) or (4).

(3)

[Chemical Formula 4]

When the urethane (meth) acrylate contains the cycloalkyl moiety, there is an advantage that the hardness can be improved due to the rigidity of the molecular structure of the cycloalkyl group. In addition, since the compound is stable to light as compared with an aryl group such as a phenyl group, there is an advantage that a hard coat composition having excellent optical characteristics can be produced.

In still another embodiment of the present invention, the urethane (meth) acrylate-based compound containing the cycloalkyl moiety is contained in an amount of 30 to 60 parts by weight, preferably 30 to 50 parts by weight, Preferably 35 to 45 parts by weight, in terms of mechanical properties. If the urethane (meth) acrylate-based compound containing the cycloalkyl moiety is less than 10 parts by weight, the mechanical properties such as hardness may be somewhat lowered. When the amount is more than 60 parts by weight, the shrinkage force is somewhat increased, Cracks and the like may occur.

(2) Oxyethylene group  Included Multifunctional  ( Mat ) Acrylate series  compound

The polyfunctional (meth) acrylate-based compound containing the oxyethylene group is included for imparting flexibility.

The polyfunctional (meth) acrylate-based compound containing oxyethylene group can be used without any limitations as commonly used in the art. The polyfunctional (meth) acrylate-based compound containing oxyethylene group may be at least one selected from the group consisting of trimethylol propane (EO) ₃ tri (meth) acrylate, trimethylol propane (EO) ₆ tri (meth) acrylate, trimethylol propane (EO) ₉ tri (meth) acrylate, glycerin (EO) ₃ tri (meth) acrylate, glycerin (EO) ₆ tri (meth) acrylate, glycerin (EO) ₉ tri (meth) acrylate, pentaerythritol (EO) ₄ tetra (meth) acrylate, pentaerythritol (EO) _8-tetra (meth) acrylate, pentaerythritol (EO) _12-tetra (meth) acrylate, dipentaerythritol (EO) ₆ hexa (meth) acrylate, dipentaerythritol (EO) ₁₂ hexa (meth) acrylate and dipentaerythritol (EO) ₁₈ hexa (meth) acrylate.

Specifically, the polyfunctional (meth) acrylate-based compound containing an oxyethylene 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 then condensing (meth) acrylic acid with the polyfunctional alcohol But it is not limited thereto.

The polyfunctional alcohol may be a polyhydric alcohol and may be specifically glycerol, trimethylol propane, pentaerythritol, or dipentaerythritol, but is not limited thereto.

The polyfunctional (meth) acrylate compound having oxyethylene group may be represented by the following general formula (5) or (6).

[Chemical Formula 5]

[Chemical Formula 6]

When the hard coating composition includes the polyfunctional (meth) acrylate compound, there is an advantage that a coating layer having improved durability can be produced. When the polyfunctional (meth) acrylate compound includes the oxyethylene group, flexibility There is also an advantage that can be given.

In another embodiment of the present invention, the polyfunctional (meth) acrylate-based compound containing the oxyethylene group is contained in an amount of 20 to 45 parts by weight, preferably 25 to 35 parts by weight, based on the total solid content of the hard coating composition But is not limited thereto.

When the oxyalkylene group-containing polyfunctional (meth) acrylate compound is contained within the above range, it is possible to produce a hard coating film having excellent durability and flexibility. When the amount of the polyfunctional (meth) acrylate compound containing oxyethylene group is less than 20 parts by weight, the impartation of flexibility may be somewhat deteriorated. When the amount is more than 45 parts by weight, securing of hardness may be somewhat difficult. .

Photoinitiator

The photoinitiator is used for the photocuring of the hard coating composition, and can be applied without limitation as long as it is generally used in the art. Specifically, the photoinitiator may be 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 hydrogen recycle type Type 2 initiator coexisting with a tertiary amine.

Specific examples of the Type 1 initiator include 4-phenoxy dichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyl trichloroacetophenone, diethoxyacetophenone, 2- Methylpropane-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2- Acetophenones such as methylpropane-1-one, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone and 1-hydroxycyclohexylphenylketone, benzoin, Benzoates such as methyl ether, benzoin ethyl ether and benzyl dimethyl 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 ' 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.

The photoinitiator may be contained in an amount of 0.1 to 5 parts by weight, preferably 1 to 4 parts by weight, based on the total solid content of the hard coat composition. When the photoinitiator is included within the above range, there is an advantage that hardness can be improved through polymerization between the compounds contained in the hard coating composition without affecting flexibility. In addition, there is an advantage that productivity can be improved by giving an appropriate curing time. Particularly, when a sufficient curing time is given, the final obtained coating film is excellent in mechanical properties, excellent adhesion can be achieved, curing shrinkage phenomenon can be prevented, and problems such as poor adhesion, breakage and curling can be prevented have.

solvent

The solvent is not limited as long as it is capable of dissolving or dispersing the above-mentioned composition and is known as a solvent of a composition for forming a coating layer 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 parts by weight, specifically 10 to 80 parts by weight, more specifically 20 to 70 parts by weight, based on the total weight of the hard coating composition. When the solvent is included within the above range, it is preferable in terms of workability. If the amount of the solvent is less than 5 parts by weight, the viscosity may be somewhat high and the workability may be deteriorated. If the amount is more than 90 parts by weight, it is difficult to control the thickness of the coating film.

Inorganic nanoparticles having a reactive functional group

In another embodiment of the present invention, inorganic nanoparticles having a reactive functional group may be further included. The inorganic nanoparticles having the reactive functional group may be selectively added to improve the hardness of the hard coat layer. Specifically, when the inorganic nanoparticles are included in the coating composition, the inorganic nanoparticles have an advantage of being able to further improve their mechanical properties. When the inorganic nanoparticles have the reactive functional groups, they can participate in the photo-curing reaction, There is an advantage that improvement can be made.

The reactive functional group may be a vinyl group such as an acryloyl group, a methacryloyl group or a vinyl ether, but is not limited thereto. The "inorganic nanoparticle having a reactive functional group" Substituted with a reactive functional group.

More specifically, the inorganic nanoparticle having a reactive functional group may have a surface substituted with a (meth) acryl functional group, and in this case, the inorganic nanoparticle having a characteristic capable of participating in the photocuring reaction. In addition, the inorganic nanoparticles are uniformly formed in the coating film, and the mechanical properties such as abrasion resistance, scratch resistance and pencil hardness can be improved.

The inorganic nanoparticles may have an average particle diameter of 1 to 100 nm, specifically 1 to 80 nm, more specifically 5 to 50 nm. When the average particle diameter of the inorganic nanoparticles satisfies the above range, there is an advantage that a uniform coating film can be formed by preventing coagulation in the composition. Further, it is possible to prevent the problem that the optical properties and the mechanical properties of the coating film are deteriorated.

The inorganic nanoparticles may be formed of at least one of 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 however comprise one or more of the group consisting of, and not limited to this may include a metal oxide that is commonly used in the art.

Specifically, the inorganic nanoparticles may be Al ₂ O ₃ , SiO ₂ , or ZrO ₂ , the surface of which is substituted with a (meth) acryl functional group. The inorganic nanoparticles may be prepared directly or commercially available ones. In the case of commercially available products, the inorganic nanoparticles may be dispersed in an organic solvent at a concentration of 10 to 80% by weight. Commercially available products include, but are not limited to, MEK-AC-2140Z, MEK-AC-4130Y and MEK-AC-5140Z (Nissan chemical).

The inorganic nanoparticles having a reactive functional group can be prepared by surface modification using the above-mentioned reactive functional group, i.e., a compound containing a (meth) acrylic functional group. The surface modification treatment can be carried out by a conventional method such as chemical modification. Specifically, the surface modification treatment can be carried out by mixing the compound containing the reactive functional group and the inorganic nanoparticles selectively in a solvent, and heating and stirring.

In some embodiments of the present invention, the inorganic nanoparticles may be included in an amount of 1 to 25 parts by weight, preferably 5 to 20 parts by weight, more preferably 5 to 15 parts by weight based on 100 parts by weight of the entire hard coating composition have. When the inorganic nanoparticles are contained in the above range, it is preferable in terms of imparting mechanical strength. If the amount of the inorganic nanoparticles is less than 1 part by weight, the mechanical properties such as abrasion resistance, scratch resistance and pencil hardness may not be sufficient. If the amount exceeds 25 parts by weight, the curability may be deteriorated and the mechanical properties may deteriorate, .

additive

The hard coating composition according to the present invention may further comprise an additive, and the additive may include, but is not limited to, one or more of the group consisting of a leveling agent and a stabilizer.

(Leveling agent)

The leveling agent may include at least one of a silicone leveling agent, a fluorine leveling agent, and an acrylic leveling agent. When the leveling agent is included in the hard coating composition, smoothness and coating properties can be imparted when the coating film is formed.

Specifically, the leveling agent may be selected from the group consisting of BYK-323, BYK-331, BYK-333, BYK-337, BYK-373, BYK-375, BYK-377, BYK-378, BYK-SILCLEAN 3700, TEGO Glide 410, TEGO Glide 411, TEGO Glide 415, TEGO Glide 420, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 455, TEGO Rad 2100, TEGO Rad 2200N, 2300, TEGO Rad 2500, 3M FC-4430, FC-4432, etc., but the present invention is not limited thereto, and a leveling agent conventionally used in the art can be applied.

The leveling agent may be included in an amount of 0.1 to 1 part by weight based on the total weight of the hard coating composition, but is not limited thereto. However, when the leveling agent is contained in the hard coating composition within the above range, the smoothness and coatability of the coating film are maximized, and the hardness and flexibility can be maintained excellent.

(stabilizator)

The stabilizer may be a hindered amine type; Phenyl salicylate system; Benzophenone type; Benzotriazole systems; Nickel derivatives; Radical scavenger; Polyphenolics; Phosphite system; And a lactone-based stabilizer.

In the present invention, the ultraviolet stabilizer means an additive added for the purpose of shielding or absorbing ultraviolet rays to protect the hard coating composition, since 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 Salicylates (absorbent), Benzophenone (absorbent), Benzotriazole (absorber), Nickel derivative (quencher), Radical Scavenger .

In the present invention, there is no particular limitation as long as it is an ultraviolet stabilizer that does not greatly change the initial color of the hard coating composition.

The heat stabilizer is a commercially applicable product, and can be used either singly or as a mixture of 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.

The stabilizer may be included in an amount of 0.1 to 10 parts by weight based on the total solid content of the hard coating composition, but is not limited thereto. When the stabilizer is contained in the above range of the total solid content of the hard coating composition, it is possible to prevent the surface of the cured coating film from being decomposed by the ultraviolet rays without lowering the hardness and flexibility, There is an advantage.

The hard coating composition according to the present invention has an antioxidant effect because it contains an antioxidant compound containing a specific functional group, specifically, a phenolic functional group and a P-based functional group or an S-based functional group. When the composition is cured to produce a film There is an advantage that the oxidation is prevented and the YI value is reduced.

The hard coating composition according to the present invention may contain, in addition to the above-mentioned components, a polymer compound, a light stimulant, an antioxidant, a UV absorber, a thermal polymerization inhibitor, An activator, a lubricant, an antifouling agent, and the like. At this time, selection and content control of each additive can be suitably selected by those skilled in the art.

< Hard coating  Film>

Another aspect of the invention relates to a hardcoat film comprising a cured product of the hardcoat composition described above.

For example, the hard coating film may be formed by applying the hard coating composition described above to one side or both sides of a transparent base film and curing the same.

The hard coating film prepared using the hard coating composition according to the present invention exhibits excellent hardness and flexibility.

The base film is not limited as long as it is a transparent polymer film.

In the present invention, the term "transparent" means that the transmittance of the visible ray is 70% or more or 80% or more. Incidentally, the case where the entire area is not transparent and the aperture ratio is 60% or more may be included.

The polymer film may be manufactured by a film-forming method or an extrusion method according to a manufacturing method, but is not limited thereto. Specifically, the transparent polymer film may be a cycloolefin-based derivative having a unit of a monomer including a cycloolefin such as norbornene or a polycyclic norbornene monomer, a cellulose (diacetylcellulose, triacetylcellulose, acetylcellulose butyrate, iso Propyl cellulose, butyryl cellulose, acetyl propionyl cellulose), ethylene vinyl acetate copolymer, polyester, polystyrene, polyamide, polyetherimide, polyacryl, polyimide, polyether sulfone, polysulfone, polyethylene , Polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyethersulfone, polymethyl methacrylate, polyethylene terephthalate, polybutyl Ren Terephthal Sites may be used polyethylene naphthalate, polycarbonate, polyurethane, and can be selected from among epoxy, non-stretched, uniaxially or biaxially stretched film.

More specifically, among the transparent substrates exemplified above, monoaxially or biaxially stretched polyester films excellent in transparency and heat resistance, cycloolefin-based derivative films excellent in transparency and heat resistance and capable of coping with the enlargement of the film, transparent and optically anisotropic A triacetylcellulose film having no transparency and a low transparency and a low cost acrylic copolymer film can be suitably used. However, the present invention is not limited thereto, and a substrate including a transparent plastic generally used in the art can be appropriately selected and used .

Plasma or corona treatment may be performed before forming the coating layer on the base film, but the present invention is not limited thereto. When the pretreatment such as plasma or corona treatment is performed on the base film, adhesion between the coating layer and the base film is increased. The plasma or corona treatment may be performed by a method commonly used in the art.

The thickness of the base film may be 8 to 1000 탆, specifically 40 to 100 탆. When the thickness of the base film is in the above-mentioned 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 can be lightened.

The coating layer can be produced using the hard coating composition described above. Specifically, the coating layer may be formed by a suitable method such as die coater, air knife, reverse roll, spray, blade, casting, gravure, microgravure, and spin coating.

The thickness of the coating layer may be 3 占 퐉 to 200 占 퐉, specifically 10 占 퐉 to 100 占 퐉, more specifically, 20 占 퐉 to 30 占 퐉, but is not limited thereto. However, when the thickness of the coating layer satisfies the above range, there is an advantage that a hard coating film having excellent hardness, flexibility, thinning, and hardly causing curling phenomenon can be produced. The thickness of the coating layer may be referred to as the thickness after drying.

After the hard coating composition is applied, it is dried at a temperature of 30 to 150 ° C. for 10 seconds to 1 hour, specifically for 30 seconds to 10 minutes by evaporation of volatiles. The hard coating composition is then cured by irradiation with UV light. The irradiation amount of the UV light may be about 0.01 to 10 J / cm ² , and may be 0.1 to 2 J / cm ² .

The hard coating film may be used for a flexible display. Specifically, the hard coating film may be used for a display such as LCD, OLED, LED, FED, various mobile communication terminals using the same, a cover glass for a touch panel of a smart phone or a tablet PC, Or as a functional layer.

Another aspect of the present invention relates to an image display apparatus including the above-mentioned hard coating 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.

Further, another aspect of the present invention relates to a window of a flexible display device including the aforementioned hard coating film.

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.

Example  1 to 8 and Comparative Example  One : Hard coating  Preparation of composition

Hard coating compositions were prepared with the ingredients as shown in Table 1 below. At this time, Sumilizer GP (Sumitomo Company) was used as the antioxidant compound represented by the formula (1), CP-4 (Mitsunobu specialty Chemical Co., Ltd.) was used as the photoinitiator, and MEK-AC-2140Z MEK (methyl ethyl ketone) was used as an external solvent.

Antioxidant compound Photoinitiator Urethane (meth) acrylate compound The polyfunctional (meth) acrylate compound Inorganic nanoparticle solvent (1-1) 2-1 CP-4 SOU-1700B DPEA-126 M-340 MEK-AC-2140Z Methyl ethyl ketone Example 1 0.5 - 3 40 20 5 8 23.5 Example 2 One - 3 40 20 5 8 23 Example 3 1.5 - 3 35 20 - 12 28.5 Example 4 0.01 - 3 35 25 5 10 21.99 Example 5 2 - 3 40 40 5 2 8 Example 6 - One 3 40 20 5 10 21 Example 7 - 0.5 3 40 20 5 10 21.5 Example 8 - 1.5 3 40 20 5 10 20.5 Comparative Example 1 - - 3 45 35 15 - 2

[Formula 1-1]

[Formula 2-1]

SOU-1700B (Shin-A T & C):

DPEA-126 (Japan Chemical):

M-340 (Miwon Specialty Chemical):

Hard coating  Production of film

Each of the hard coating compositions prepared in Examples and Comparative Examples was dried on one side of a polyimide film for optical use (Mitsubishi Gas Chemical Co., Ltd., 100 占 퐉, L-3430), and then coated in an oven at 110 占 폚 for 5 minutes After drying, a hard coat film was prepared by curing the metal halide lamp at a light amount of 1.5J.

The physical properties of the thus-prepared hard coating film were measured as follows, and the results are shown in Table 2 below.

(1) Pencil Hardness

Pencil hardness was measured by applying a load of 1 kg using a pencil hardness tester (PHT, Kobo Scientific Co., Ltd.). The pencil was made of Mitsubishi product and was performed five times per pencil hardness. When two or more pieces of cigarettes were found to be defective, the maximum hardness determined as good was recorded.

Good 0: Good

Kith 1: Good

Gas 2 or higher: Bad

(2) Abrasion resistance

The 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 # 0000 was used and it was judged whether or not the surface was scratched.

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 their average values were recorded and the results are shown in Table 2 below. The adhesion measurement standard is as follows. That is, if none of them were peeled off, they were recorded as 100/100.

Adhesion = n / 100

n: Number of unfixed rectangles of the entire rectangle

100: total number of squares

(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 glass plates was measured at 25 DEG C and 50% RH, The results are shown in Table 2 below.

(5) Mandrell

In order to evaluate the flexibility and the cracking property of the coating film, 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 folded by hand, The smallest diameter is indicated.

(6) YI

CM-3600d (Konica Corporation, Japan) was used to evaluate the yellowness index (YI) value. The measurement light source was D65, the viewing angle was 2 degrees, and the measurement area was D1925 mode. The YI value of the coated film sample cut to 5 cm x 5 cm was measured and shown in Table 2 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Pencil hardness 5H 5H 5H 5H 4H 4H 5H 5H 2B Abrasion resistance A A A A A A A A D Adhesiveness 100/100 100/100 100/100 100/100 100/100 100/100 100/100 100/100 92/100 curl 8mm 6mm 7mm 8mm 7mm 7mm 8mm 7mm 14mm Mandrell 6φ 6φ 8φ 7φ 6φ 8φ 7φ 7φ 12φ YI 2.0 1.7 1.5 2.1 1.9 1.8 1.9 1.8 3.5

Referring to Table 2, the hard coating film according to the Example exhibited excellent effects both in pencil hardness, scratch resistance, adhesion, curl and mandol test, and in particular, it exhibited a small YI value, It was found that the composition exhibited excellent color fading resistance.

Claims (11)

An antioxidant compound represented by Formula 1 or 2; Acrylate compounds; And a hard coat composition comprising a photoinitiator:
[Chemical Formula 1]

(2)

In formulas (1) and (2)
R1 to R28 each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms,
Each of L1 to L5 independently represents a linear or branched alkylene having 1 to 10 carbon atoms. The method according to claim 1,
Wherein the antioxidant compound is contained in an amount of 0.05 to 100 parts by weight based on 100 parts by weight of the photoinitiator. The method according to claim 1,
Wherein the photoinitiator is included in an amount of 0.1 to 5 parts by weight based on the total solid content of the hard coat composition. The method according to claim 1,
Wherein the acrylate compound is at least one member selected from the group consisting of a urethane (meth) acrylate compound containing a cycloalkyl moiety and a polyfunctional (meth) acrylate compound containing an oxyethylene group. 5. The method of claim 4,
Wherein the urethane (meth) acrylate-based compound containing the cycloalkyl moiety is contained in an amount of 30 to 60 parts by weight based on the total solid content of the hard coat composition. 5. The method of claim 4,
Wherein the oxyethylene group-containing polyfunctional (meth) acrylate compound is contained in an amount of 20 to 45 parts by weight based on the total solid content of the hard coating composition. The method according to claim 1,
And further comprising inorganic nanoparticles having reactive functional groups. 8. The method of claim 7,
Wherein the inorganic nanoparticles are contained in an amount of 1 to 25 parts by weight based on 100 parts by weight of the entire hard coating composition. A hardcoat film comprising a cured product of the hard coating composition of any one of claims 1 to 8. An image display device comprising the hard coating film according to claim 9. A window of a flexible display device comprising a hard coating film according to claim 9.