WO2018212547A1 - Hard coating film and image display apparatus comprising same - Google Patents

Abstract

The present invention relates to: a hard coating film which comprises the cured product of a hard coating composition on at least one surface of a polyimide-based substrate film, is controlled such that the refractive index difference between the substrate film and the cured product of the hard coating composition is at most 0.03, and thus can be applied to a flexible image display apparatus and prevent the occurrence of an interference pattern; and an image display apparatus comprising the hard coating film.

Description

Hard coating film and an image display device comprising the same

The present invention relates to a hard coat film and an image display device including the same.

In an image display device such as a cathode ray tube display device (CRT), a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), or an electronic paper, the image display surface is exposed to light emitted from an external light source. It is required to reduce the reflection and to increase the visibility. In this connection, by using an optical laminate (for example, an antireflective laminate) in which an anti-glare layer or an antireflection layer is formed on a light transmissive substrate, the reflection of the image display surface of the image display apparatus can be reduced and the visibility can be improved. The method is generally done.

However, when the refractive index of the light transmissive substrate and the refractive index of the hard coating layer are different, there is a problem that an interference fringe may occur, and researches for improving this have been conducted.

In this regard, the Republic of Korea Patent No. 10-1063902 is configured to suppress the occurrence of the interference fringe as described above comprises a plurality of transparent layers having different refractive indices, the ten-point average roughness of the contact interface between the plurality of transparent layers (Rz) is characterized in that the light-scattering interface of 0.72㎛ ≤ Rz ≤ 3.5㎛, but this has a problem that the manufacturing process is complicated and the manufacturing time is increased because a plurality of transparent layers to be formed.

In addition, Korean Patent Laid-Open No. 10-2013-0117694 includes a base film containing a (meth) acrylic resin as a main component and a hard coating layer as a structure for suppressing occurrence of the interference fringe as described above, and on the side of the hard coating layer. Although a commercial layer in which the material constituting the base film and the material constituting the hard coating layer are formed in the vicinity of an interface is formed, the acrylic resin is vulnerable to a flexible property to which repetitive stress is applied. However, there is a problem that cannot be applied to a flexible image display device that is recently developed in various fields.

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) Republic of Korea Patent No. 10-1063902 (2011.09.02.)

(Patent Document 2) Republic of Korea Patent Publication No. 10-2013-0117694 (2013.10.28.)

An object of the present invention is to provide a hard coating film which can be applied to a flexible image display device and can prevent generation of interference fringes, and an image display device including the same.

Hard coating film of the present invention for achieving the above object comprises a cured product of the hard coating composition on at least one side of the polyimide-based substrate, the difference between the refractive index of the substrate; and the cured product of the hard coating composition; 0.03 or less It is characterized by.

In addition, the image display device of the present invention is characterized in that it comprises the above-described hard coating film.

The hard coating film according to the present invention can be applied to a flexible image display device by including a polyimide base material having excellent bending durability, wherein the difference in refractive index between the polyimide base material and the cured product of the hard coating composition is 0.03. By controlling below, the occurrence of interference fringes is prevented and hardness and adhesion are also excellent.

In addition, the image display apparatus according to the present invention may be a flexible image display apparatus by including the above-described hard coating film, there is an advantage that interference fringes are also prevented.

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

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

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

<Hard Coating Film>

Hard coating film according to an aspect of the present invention comprises a cured product of the hard coating composition on at least one surface of the polyimide-based substrate, the difference between the refractive index of the substrate; and the cured product of the hard coating composition; adjusted to 0.03 or less Characterized in that. Moreover, according to one embodiment of the present invention, the difference in refractive index is more preferably less than 0.02. As described above, the hard coating film of the present invention can be applied to a flexible image display device using a polyimide-based substrate having excellent bending durability as a substrate, and the difference between the refractive index of the cured product of the substrate and the hard coating composition is 0.03 or less. By adjusting to prevent the occurrence of interference fringes, there is also an advantage in hardness and adhesion is also excellent.

Polyimide base material

The hard coat film according to one aspect of the present invention includes a polyimide substrate.

As described above, the hard coating film according to an embodiment of the present invention includes a polyimide-based substrate having excellent durability (bending durability) against repeated bending, and thus, there is an advantage that it can be applied to a flexible image display apparatus.

In the present invention, the polyimide base material means a base material containing a polyimide compound as a main component, and examples thereof include, but are not limited to, polyimide, polyamide imide, and the like. Can be used without particular limitation.

As an example, the polyimide substrate may be obtained by polymerizing a monomer including tetracarboxylic dianhydride and diamine.

Although it does not restrict | limit especially as said tetracarboxylic dianhydride, Aliphatic tetracarboxylic dianhydride and aromatic tetracarboxylic dianhydride are mentioned.

Examples of the aliphatic tetracarboxylic dianhydride include bicyclo [2.2.2] octo-7-ene-2,3,5,6-tetracarboxylic dianhydride and bicyclo [2.2.2] octane-2,3 , 5,6-tetracarboxylic dianhydride, 5- (dioxotetrahydrofuryl-3-methyl) -3-cyclohexene-1,2-dicarboxylic acid anhydride, 4- (2,5-dioxo Tetrahydrofuran-3-yl) -tetraline-1,2-dicarboxylic anhydride, tetrahydrofuran-2,3,4,5-tetracarboxylic dianhydride, bicyclo-3,3 ', 4,4'-tetracarboxylic dianhydride, 3c-carboxymethylcyclopentane-1r, 2c, 4c-tricarboxylic acid 1,4,2,3- dianhydride, 1,2,4,5-cyclohexane Tetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, and the like.

Moreover, as said aromatic tetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyl tetracarboxylic dianhydride, 2,2', 3,3'-biphenyl tetracarboxylic dianhydride, 2,3 ', 3,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, oxydiphthalic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3 ', 4,4'-diphenylsulfontetracarboxylic dianhydride, m-terphenyl-3,3', 4,4'-tetracarboxylic dianhydride, 4,4 '-(2, 2-hexafluoroisopropylene) diphthalic dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, Bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6, 7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2-bis (3, 4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3 , 3-hexafluoropropane dianhydride, (1,1 ': 3', 1 "-terphenyl) -3,3", 4,4 "-tetracarboxylic dianhydride, 4,4 '-(dimethyl Siladiyl) diphthalic dianhydride, 4,4 '-(1,4-phenylenebis (oxy)) diphthalic dianhydride, etc. are mentioned.

It is preferable that it is aromatic tetracarboxylic dianhydride from a viewpoint of obtaining the polyimide base material which has the outstanding chemical and physical property among the tetracarboxylic dianhydrides mentioned above, and it is more preferable that it is biphenyl tetracarboxylic dianhydride. And 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 2,3 ', 3,4'- It is more preferable that it is biphenyl tetracarboxylic dianhydride.

In addition, the above-mentioned tetracarboxylic dianhydride may be used independently, and may be used in combination of 2 or more type.

Although it does not restrict | limit especially as said diamine, Aliphatic diamine and aromatic diamine are mentioned.

Examples of the aliphatic diamines include diaminobutane, diaminopentane, diaminohexane, diaminoheptane, diaminooctane, diaminononane, diaminodecane, diaminoundecane, diaminododecane, and 1,4-diaminocyclo. Hexane, 1,3-diaminocyclohexane, 1,2-diaminocyclohexane, 3-methyl-1,4-diaminocyclohexane, 5,5-dimethylcyclohexylamine, 1,3-bisaminomethylcyclo Hexane, bis (4,4'-aminocyclohexyl) methane, bis (3,3'-methyl-4,4'-aminocyclohexyl) methane, bis (aminomethyl) norbornane, bis (aminomethyl)- Tricyclo [5, 2, 1, 0] decane, isophorone diamine, 1, 3- diamino adamantane, etc. are mentioned.

As the aromatic diamine, p-phenylenediamine, metaphenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 4,4'-diaminodiphenylmethane, 4,4'-dia Minodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-bis ( 4-aminophenyl) sulfide, 4,4'-diaminodiphenylsulfone, 4,4'-diaminobenzanilide, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4 -Aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) Biphenyl, 2,2-bis (4-aminophenoxyphenyl) propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2, 2-bis [4- (4-aminophenoxy) phenyl] hexafluoroprop It can be given.

From the viewpoint of obtaining a polyimide base material having excellent chemical and physical properties among the above-described diamines, aromatic diamines are preferred, and p-phenylenediamines are more preferred.

In addition, the diamine mentioned above may be used independently and may be used in combination of 2 or more type.

As mentioned above, a polyimide base material can be obtained by superposing | polymerizing the monomer containing tetracarboxylic dianhydride and diamine. In more detail, (1) tetracarboxylic dianhydride and diamine are made to react in an organic solvent, a polyamic acid is synthesize | combined, and (2) a polyimide base material can be manufactured by imidating the obtained polyamic acid. .

(1) Synthesis of Polyamic Acid

The polyamic acid can be synthesized by reacting tetracarboxylic dianhydride and diamine in an organic solvent.

It is preferable to perform this reaction by melt | dissolving a diamine in the organic solvent and gradually adding tetracarboxylic dianhydride, stirring the obtained diamine solution.

The organic solvent that can be used is not particularly limited, but may be an amide solvent such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, or N, N-diethylacetamide. ; cyclic ester solvents such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, and α-methyl-γ-butyrolactone; Carbonate solvents such as ethylene carbonate and propylene carbonate; Glycol solvents such as triethylene glycol; phenol solvents such as m-cresol, p-cresol, 3-chlorophenol and 4-chlorophenol; Acetophenone; 1,3-dimethyl-2-imidazolidinone; Sulfolane; Dimethyl sulfoxide, etc. are mentioned. In addition, phenol, O-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cello Solvate, tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol And general organic solvents such as ethanol, xylene, toluene, chlorobenzene, terpene, mineral spirit, and petroleum naphtha solvent.

It is preferable to use an amide solvent among these, The said organic solvent may be used independently and can be used in combination of 2 or more type.

(2) Preparation of Polyimide Substrate

A polyimide base material can be manufactured by imidating the polyamic acid obtained by said (1).

Production of a polyimide substrate can be carried out by, for example, casting a solution containing polyamic acid on a support and heating it.

The solution containing the polyamic acid may include a polyamic acid and an organic solvent, and may further include an imidization catalyst, an organic phosphorus-containing compound, inorganic fine particles, and the like, as necessary.

As the polyamic acid, one obtained in the above (1) can be used. Under the present circumstances, polyamic acid may be used independently and may be used in combination of 2 or more type. Moreover, it is preferable that content of polyamic acid is 10-30 mass% with respect to the solution whole quantity containing polyamic acid.

As the solvent, the above-mentioned organic solvent may be used.

The imidization catalyst may play a role of improving physical properties (elongation, heat insulation resistance, etc.) of the polyimide film.

Specifically, the imidation catalyst may be a substituted or unsubstituted nitrogen-containing heterocyclic compound and an N-oxide compound; Substituted or unsubstituted amino acid compound; Aromatic hydrocarbon compounds having a hydroxyl group; An aromatic heterocyclic compound is mentioned, but it is not limited to this.

More specifically, 1,2-dimethylimidazole, N-methylimidazole, N-benzyl-2-methylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 5 -Methylbenzimidazole, N-benzyl-2-methylimidazole, isoquinoline, 3,5-dimethylpyridine, 3,4-dimethylpyridine, 2,5-dimethylpyridine, 2,4-dimethylpyridine, 4- n-propylpyridine and the like.

Specific examples of the organic phosphorus-containing compound include monocaproyl phosphate ester, monooctyl phosphate ester, monolauryl phosphate ester, monomyristyl phosphate ester, monocetyl phosphate ester, monostearyl phosphate ester and triethylene glycol monotridecyl ether. Monophosphate ester, tetraethylene glycol monolauryl ether, monophosphate ester of diethylene glycol monostearyl ether, dicaproyl phosphate ester, dioctyl phosphate ester, dicapryl phosphate ester, dilauryl phosphate ester, Dimyristyl phosphate ester, dicetyl phosphate ester, distearyl phosphate ester, diphosphate ester of tetraethylene glycol mononeopentyl ether, diphosphate ester of triethylene glycol monotridecyl ether, diethylene glycol monolauryl ether Phosphate Ester, Diethylene Glycol The phosphoric acid esters, amine salts of these phosphoric acid esters such as di-phosphate esters of noseute aryl ethers can be used. As the amine salt, ammonia, monomethylamine, monoethylamine, monopropylamine, monobutylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, trimethylamine, triethylamine, tripropylamine, tributyl Amine salts, such as amine, monoethanolamine, ethanolamine, and triethanolamine, are mentioned, but it is not limited to these. The said organic phosphorus containing compound may be used independently and may be used in combination of 2 or more type.

Specific examples of the inorganic fine particles include inorganic oxide powders such as fine titanium dioxide powder, silicon dioxide (silica) powder, magnesium oxide powder, aluminum oxide (alumina) powder, and zinc oxide powder; Inorganic nitride powders such as particulate silicon nitride powder and titanium nitride powder; Inorganic carbide powders such as silicon carbide powder; Inorganic salt powders such as particulate calcium carbonate powder, calcium sulfate powder, and barium sulfate powder, but are not limited thereto. These inorganic fine particles may be used alone, or may be used in combination of two or more thereof. In addition, in order to uniformly disperse the inorganic fine particles in the solution containing the polyamic acid, a means known per se can be applied.

As a support for softening the solution containing the polyamic acid, a known support such as a stainless steel substrate and a stainless steel belt may be used, but is not limited thereto. At this time, the support is preferably smooth, and from the viewpoint of enabling continuous production, it is preferable that the support is an endless support such as an endless belt.

Although it does not restrict | limit especially as a casting | flow_spread method of the solution containing polyamic acid, It is preferable that they are extrusion coating and melt coating.

If the solution containing polyamic acid is cast | flow_spread to a support body, the coating film which has self-supportability can be obtained.

At this time, the solution containing a surface treating agent can also be apply | coated to the single side | surface or both surfaces of the coating film which has obtained self-supportability as needed. In addition, in this specification, the process of the polyimide base material with the said surface treating agent is not included in the "surface treatment of a polyimide base material" mentioned later.

The solution containing the surface treating agent may include a surface treating agent and an organic solvent.

Specific examples of the surface treating agent include a silane coupling agent, a borane coupling agent, an aluminum coupling agent, an aluminum chelating agent, a titanate coupling agent, an iron coupling agent, a copper coupling agent, and the like, but are not limited thereto. Among these, it is preferable to use a silane coupling agent and a titanate coupling agent.

Specific examples of the silane coupling agent include epoxysilanes such as γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyl diethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Coupling agents; Vinylsilane-based coupling agents such as vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane and vinyltrimethoxysilane; acrylic silane coupling agents such as γ-methacryloxypropyl trimethoxysilane; N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ Aminosilane-based coupling agents such as aminopropyltrimethoxysilane; γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, and the like, but are not limited thereto.

Moreover, as said titanate coupling agent, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraisopropyl bis (dioctyl force Fight) Titanate, tetra (2, 2-diallyloxymethyl-1-butyl) bis (di-tridecyl) phosphite titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pi Phosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyl tricumylphenyl titanate, and the like, but is not limited thereto.

It is preferable to use an aminosilane coupling agent among the surface treating agents mentioned above, and (gamma) -aminopropyl-triethoxysilane, N- (beta)-(aminoethyl)-(gamma) -aminopropyl- triethoxysilane, and N- (amino Carbonyl) -γ-aminopropyltriethoxysilane, N- [β- (phenylamino) -ethyl] -γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, N- It is more preferable to use phenyl-γ-aminopropyltrimethoxysilane, and still more preferably to use N-phenyl-γ-aminopropyltrimethoxysilane.

The surface treatment agent mentioned above can also be used individually or in combination of 2 or more types.

Specific examples of the organic solvent, the specific examples of the organic solvent used in the synthesis of the polyamic acid described above may be equally applied.

As a coating method to the coating film which has the self-support of the solution containing the said surface treating agent, for example, the gravure coating method, the spin coating method, the silk screen method, the dip coating method, the spray coating method, the bar coating method, the knife coating method And known coating methods such as a roll coating method, a blade coating method and a die coating method.

The imidation of polyamic acid generate | occur | produces by heating the coating film obtained by apply | coating the coating film which has thus obtained self-support, or the solution containing the coating film which has self-support, and a surface treating agent, and produces a polyimide base material. Can be.

Although the heating temperature of the said imidation will not be restrict | limited especially if it is temperature which imidation advances, It is preferable that it is 100-550 degreeC, and it is more preferable that it is 100-400 degreeC. At this time, it is preferable to perform heating stepwise, for example, it heats to 100-170 degreeC as a 1st heat processing, heats it to 170-220 degreeC as a 2nd heat processing, and 220-220 as a 3rd heating process. It can heat to 400 degreeC and can heat to 400-550 degreeC as a 4th heat processing.

At the time of heating, you may extend | stretch a film as needed. Thereby, physical properties, such as a thermal expansion coefficient of a polyimide base material, can be controlled suitably. At this time, the stretching method may be biaxial stretching such as sequential biaxial stretching, simultaneous biaxial stretching, or uniaxial stretching. It is preferable that a draw ratio is 2 to 10 times, respectively in a vertical axis direction and a horizontal axis direction. Moreover, you may perform a relaxation process after extending | stretching from a viewpoint of improving the dimensional stability of a polyimide base material.

The imidation of the polyamic acid may be performed by chemical imidation instead of the heating or with heating.

Although the specific method of the said chemical imidation is not restrict | limited, For example, it can carry out by casting | flow_spreading on the support body the solution obtained by further adding a dehydrating agent and a catalyst to the solution containing the polyamic acid mentioned above, and performing it.

Although it does not restrict | limit especially as said dehydrating agent, Aliphatic acid anhydride, aromatic acid anhydride, alicyclic acid anhydride, heterocyclic acid anhydride, etc. are mentioned. Specific examples include acetic anhydride, propionic anhydride, butyric anhydride, formic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, benzoic anhydride, picolinic anhydride, and the like. Among these, it is preferable to use acetic anhydride. In addition, the said dehydrating agent may be used independently and can also be used in combination of 2 or more type.

Examples of the catalyst include aliphatic tertiary amines, aromatic tertiary amines, heterocyclic tertiary amines, and the like. Specifically, trimethylamine, triethylamine, dimethylaniline, pyridine, β-picolin, isoquinoline, Quinoline etc. are mentioned, Among these, it is preferable to use isoquinoline, but it is not limited to this.

About casting and heating to the said support body, a polyimide base material can be manufactured by carrying out by a method similar to the above.

Moreover, as a polyimide base material, the well-known polyimide base material manufactured by making tetracarboxylic dianhydride and diisocyanato react, besides what was mentioned above can also be used, for example.

Hard coating  Composition

Hard coating film according to an aspect of the present invention comprises a cured product of the hard coating composition, and adjusts the difference between the refractive index of the cured product of the hard coating composition and the above-described polyimide-based substrate to 0.03 or less, preferably less than 0.02 This prevents the occurrence of interference fringes, and also has excellent advantages in hardness and adhesion.

High refractive index  Suzy

According to one embodiment of the present invention, the hard coating composition has an advantage of reducing the difference in refractive index between the cured product of the hard coating composition comprising the same and the polyimide-based substrate by including a high refractive resin. According to one embodiment of the present invention, in order to minimize the difference in refractive index with the polyimide-based substrate, the refractive index after curing of the high refractive resin is preferably 1.55 or more.

In the present invention, the kind of the high refractive resin is not particularly limited, but specifically, may be a polymer resin or a photocurable (meth) acrylate oligomer or monomer, and more specifically, thioether, sulfone, cyclic thiophene, Resin containing sulfur such as thiadiazole type, thianthrene type and the like; Halogen derivative resins containing bromine, iodine groups and the like; Resins containing phosphorus such as carbazole-based, phosphonate-based, phosphazene-based and the like; Fluorene derivative resins; Biphenol derivative resins; And cardo-based derivative resins; It may be to include one or more selected from the group consisting of.

The content of the above-mentioned high refractive resin is relatively controlled to adjust the refractive index of the cured product of the hard coating composition including the same, but is not particularly limited in the present invention, but according to an embodiment of the present invention, the total weight of the hard coating composition is 100% by weight. It may be included in 10 to 100% by weight, preferably 20 to 100% by weight, more preferably 30 to 100% by weight relative to%. When the content of the high refractive resin satisfies the above range, there is an advantage in that it is easy to reduce the difference in refractive index with the polyimide substrate used together by increasing the refractive index of the cured product of the hard coating composition including the same.

According to one embodiment of the present invention, the hard coating composition may further include one or more selected from the group consisting of a light transmitting resin, a solvent and a photoinitiator.

Translucent  Suzy

The hard coating composition of the present invention may further include a translucent resin, and the translucent resin may include a photocurable (meth) acrylate oligomer or (meth) acrylate monomer that is curable by ultraviolet rays.

The photocurable (meth) acrylate oligomers may be commercially available epoxy (meth) acrylate oligomers, urethane (meth) acrylate oligomers, and the like, and preferably include urethane (meth) acrylate oligomers.

The urethane (meth) acrylate oligomer may be used in the art without limitation, but is preferably prepared by urethane reaction of a polyfunctional (meth) acrylate having an hydroxy group in a molecule with a compound having an isocyanate group in the presence of a catalyst You can also use

Specific examples of the (meth) acrylate having a hydroxy group in the molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and capro Lactone ring-opening hydroxyacrylates, pentaerythritol tri / tetra (meth) acrylate mixtures, and dipentaerythritol penta / hexa (meth) acrylate mixtures, and the like, but are not limited thereto. The above can be used in combination.

Specific examples of the compound having an isocyanate group in the molecule include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, 1, 5-diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis (isocyanatomethyl) cyclohexane, trans-1,4-cyclohexene diisocyanate, 4,4 '-Methylenebis (cyclohexyl isocyanate), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethylxylene-1, 3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis (2,6-dimethylphenylisocyanate), 4,4'-oxybis (phenylisocyanate), hexamethylene diisocyanate Trifunctional Isocyanates and Trimethanepropanol Adducts Toluenedi Derived from SOCCIA but are the carbonate or the like, not limited to this, and these may be used alone or in combination of two or more.

Said photocurable (meth) acrylate monomer means having a unsaturated group, such as a (meth) acryloyl group, a vinyl group, a styryl group, an allyl group, in a molecule | numerator, and including a (meth) acryloyl group as a photocurable functional group. desirable.

The monomer containing a (meth) acryloyl group as mentioned above specifically, neopentyl glycol acrylate, 1, 6- hexanediol (meth) acrylate, a propylene glycol di (meth) acrylate, triethylene glycol di (meth) ) Acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylol ethane tri (meth) Acrylate, 1,2,4-cyclohexanetetra (meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tree ( Meta) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth ) Acrylate, tripentaerythritol tri (meth) acrylate, tripentaerythritol hexatri (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth) acrylate, iso-decyl (meth) acrylate , Stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (meth) acrylate, isobornol (meth) acrylate, and the like, but are not limited to these, these are each It can be used individually or in combination of 2 or more types.

The content of the translucent resin is not particularly limited in the present invention, but may be included in an amount of 1 to 80% by weight based on 100% by weight of the total hard coating composition including the same. When the light-transmitting resin is included in the above range, the hardness is improved, there is an advantage that can suppress the curl generation.

Photoinitiator

The hard coating composition of the present invention may further include a photoinitiator.

The photoinitiator serves to change the liquid hard coating liquid to a solid phase, and any photoinitiator used in the art may be used without particular limitation.

Specifically, hydroxy ketones, amino ketones, hydrogen decyclic photoinitiator, etc. are mentioned, More specifically, 2-methyl-1- [4- (methylthio) phenyl] 2-morpholine propanone-1, diphenyl Ketone, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenyl-1-one, 4-hydroxycyclophenylketone, 2,2-dimethoxy-2-phenyl-acetophenone, anthraquinone, fluorene , Triphenylamine, carbazole, 3-methylacetophenone, 4-knoloacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexylphenylketone, benzophenone , Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide and the like, but are not limited thereto, and these may be used alone or in combination of two or more thereof.

The content of the photoinitiator is not particularly limited in the present invention, but is preferably included in 0.1 to 10% by weight, specifically 1 to 5% by weight relative to the total 100% by weight of the hard coating composition comprising the same. When the photoinitiator satisfies the above range, physical properties of the cured product of the hard coating composition may be improved due to sufficient degree of curing.

solvent

The hard coating composition of the present invention may further include a solvent.

The solvent may dissolve or disperse the aforementioned components, and any solvent may be used without particular limitation as long as it is used as a solvent in the art.

Specific examples of the solvent include alcohols (methanol, ethanol, isopropanol, butanol, methyl cellulose, ethyl cellulose, etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, and diethyl ketone). , Dipropyl ketone, cyclohexanone, etc.), acetate type (ethyl acetate, propyl acetate, normal butyl acetate, tertiary butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol Monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxy butyl acetate, methoxypentyl acetate, etc.), hexane type (hexane, heptane, octane etc.), benzene type (benzene, toluene, xylene etc.), ether type ( Diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether Le, propylene glycol monomethyl ether, etc.) may be preferably used, but is not limited thereto, and these may be used alone or in combination of two or more thereof.

The content of the solvent in the present invention is not particularly limited, but may be included in 10 to 95% by weight relative to the total 100% by weight of the hard coating composition comprising the same. When the content of the solvent is included in the above range, it is easy to control the viscosity of the hard coating composition to improve the workability, it is possible to sufficiently proceed the swelling of the base film used together, and can save time during the drying process economical This is an excellent advantage.

In addition, the hard coating composition of the present invention may further include additives such as other polymer compounds, curing agents, leveling agents, adhesion promoters, antioxidants, ultraviolet absorbers, anti-agglomerating agents as necessary.

As described above, the hard coat film according to an aspect of the present invention comprises a cured product of the hard coating composition on at least one side of the polyimide-based substrate, the difference between the refractive index of the cured product of the substrate and the hard coating composition is 0.03 or less It is characterized by adjusting to. Moreover, according to one embodiment of the present invention, the difference in refractive index is more preferably less than 0.02. As described above, the hard coating film of the present invention can be applied to a flexible image display device using a polyimide-based substrate having excellent bending durability as a substrate, and the difference between the refractive index of the cured product of the substrate and the hard coating composition is 0.03 or less. By adjusting to prevent the occurrence of interference fringes, there is also an advantage in hardness and adhesion is also excellent.

<Image display device>

Another aspect of the present invention is an image display apparatus including the above-described hard coating film.

The image display device is not particularly limited, and examples thereof include liquid crystal display (LCD), field emission display (FED), plasma display (PDP), organic light emitting device (OLED), flexible display, and the like. Can be.

In particular, the image display device according to an embodiment of the present invention includes a hard coating film having a polyimide-based base material having excellent bending durability, which is more advantageous when applied to the flexible image display device.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it is apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. Naturally, such modifications and variations fall within the scope of the appended claims. In the following Examples and Comparative Examples, "%" and "parts" indicating contents are by weight unless otherwise specified.

Production Example : Hard coating  Preparation of the composition

Production Example  One.

Pentaerythritol triacrylate 25% by weight, fluorene-based high refractive acrylate (Osaka Chemical Co., OGSOL EA-F5003, refractive index after curing 1.58) 25% by weight, methyl ethyl ketone (large crystal) 10% by weight, propylene glycol 37 weight% of monomethyl ether (a gold refiner company), 2.5 weight% of 1-hydroxy cyclohexyl phenyl- ketones, and 0.5 weight% of a leveling agent (BYK Chemi Co., BYK3570) were mix | blended using a stirrer, and polypropylene A hard coating composition was prepared by filtration using a filter made of (PP) material.

Production Example  2.

Pentaerythritol triacrylate 25% by weight, cardo-based high refractive acrylate (Taoka Chemical Co., Ltd., TBIS-MPEC, refractive index after curing 1.59) 25% by weight, 10% by weight of methyl ethyl ketone (large gold), propylene glycol monomethyl 37 weight% of ether (a fine gold company), 2.5 weight% of 1-hydroxy cyclohexyl phenyl- ketones, and 0.5 weight% of a leveling agent (BYK Chemi Co., BYK3570) were mix | blended using a stirrer, polypropylene (PP A hard coating composition was prepared by filtration using a filter made of) material.

Production Example  3.

25% by weight pentaerythritol triacrylate, 25% by weight of bisfluorene-based high refractive acrylate (Miwon Specialty Chemical Co., HR6042, refractive index after curing 1.61), 10% by weight methyl ethyl ketone (large gold company), propylene glycol monomethyl 37 weight% of ether (a fine gold company), 2.5 weight% of 1-hydroxy cyclohexyl phenyl- ketones, and 0.5 weight% of a leveling agent (BYK Chemi Co., BYK3570) were mix | blended using a stirrer, polypropylene (PP A hard coating composition was prepared by filtration using a filter made of) material.

Production Example  4.

50% by weight pentaerythritol triacrylate, 10% by weight methyl ethyl ketone (fine gold), 37% by weight propylene glycol monomethyl ether (large gold), 1-hydroxycyclohexyl-phenyl-ketone 2.5% %, 0.5% by weight of leveling agent (BYK Chemie, BYK3570) using a stirrer and filtered using a filter made of polypropylene (PP) to prepare a hard coating composition.

Example  And Comparative example : Hard coating  Manufacture of film

Example  One.

Using the hard coating composition of Preparation Example 1, the coating was applied on a polyimide (PI) film (refractive index of 1.55) of 80㎛ thickness after the curing to 10㎛ thickness, and then the solvent was dried at 80 ℃ for 2 minutes , UV accumulated light amount was irradiated to 1J / cm ² and cured to prepare a hard coat film. In this case, the refractive index after curing of the cured product of the hard coating composition was 1.545, and the difference in refractive index of the cured product of the polyimide base film and the hard coating composition was 0.005.

At this time, the refractive index after coating the hard coating composition to a silicon wafer thickness of 1㎛ after curing, the refractive index of 589nm wavelength was measured using a reflectometer (STX-4000, Kmac).

Example  2.

Instead of using the hard coating composition of Preparation Example 1 in Example 1, a hard coating film was prepared in the same configuration and method as in Example 1 except for using the hard coating composition of Preparation Example 2. In this case, the refractive index after curing of the cured product of the hard coating composition was 1.55, and the difference in refractive index of the cured product of the polyimide base film and the hard coating composition was 0.

At this time, the method of measuring the refractive index was measured in the same manner as in Example 1 described above.

Example  3.

Instead of using the hard coating composition of Preparation Example 1 in Example 1, a hard coating film was prepared in the same configuration and method as in Example 1 except for using the hard coating composition of Preparation Example 3. In this case, the refractive index after curing of the cured product of the hard coat composition was 1.56, and the difference in refractive index of the cured product of the polyimide base film and the hard coat composition was 0.01.

At this time, the method of measuring the refractive index was measured in the same manner as in Example 1 described above.

Comparative example  One.

Instead of using the hard coating composition of Preparation Example 1 in Example 1, a hard coating film was prepared in the same configuration and method as in Example 1 except for using the hard coating composition of Preparation Example 4. At this time, the refractive index after hardening of the hardened | cured material of a hard-coating composition was 1.51, and the difference of the refractive index of the hardened | cured material of the said polyimide base film and the hard-coating composition was 0.04.

Comparative example  2.

Except for using the polyimide substrate of Preparation Example 1 in Example 1, the same configuration and method as in Example 1 except for using a polymethyl methacrylate (PMMA) film (refractive index 1.5) of 80 ㎛ thickness To prepare a hard coat film. In this case, the refractive index after curing of the cured product of the hard coating composition was 1.545, and the difference in refractive index of the cured product of the polymethylmethacrylate base film and the hard coating composition was 0.045.

Comparative example  3.

Instead of using the polyimide substrate of Preparation Example 1 in Example 1, except using a 80 μm-thick polymethyl methacrylate (PMMA) film (refractive index 1.5), using the hard coating composition of Preparation Example 4 And to prepare a hard coat film in the same configuration and method as in Example 1. In this case, the refractive index after curing of the cured product of the hard coating composition was 1.51, and the difference in refractive index of the cured product of the polymethyl methacrylate base film and the hard coating composition was 0.01.

Experimental Example

Experimental Example  1: Evaluation of interference pattern prevention

The base film surface was bonded to the black acrylic plate by using a transparent adhesive so that the hard coating layer surface of the hard coating film prepared in Examples 1 to 3 and Comparative Examples 1 to 3 to the top. Under the three-wavelength lamp, the interference fringe generation level of the hard coating layer surface was visually evaluated as follows, and the results are shown in Table 1 below.

<Evaluation Criteria>

○: interference fringes are not visible

△: interference pattern is weakly recognized

×: Interference pattern is clearly recognized

Experimental Example  2: pencil hardness experiment

In the hard coating film of Examples 1 to 3 and Comparative Examples 1 to 3, after fixing the substrate film surface to the glass so that the hard coating layer surface to the upper side, using a pencil hardness tester (PHT, Korea Stone Company), 1kg load The pencil hardness was measured under. Using a pencil of the same hardness, the test was carried out five times at a length of 1cm, and the hardness that does not appear even after performing four times or more is described in Table 1 as the pencil hardness.

Experimental Example  3: adhesion test

In the hard coating films of Examples 1 to 3 and Comparative Examples 1 to 3, the base film surface was bonded to the glass using a transparent adhesive so that the hard coating layer faced upwards, and then in a square shape of 100 horizontally and vertically at 1 mm intervals. After scratching the hard-coated surface using a cutter knife, the adhesion test was carried out three times using a nichibang tape. The results are shown in Table 1 below, and the numerical values shown in Table 1 below are expressed as "number of squares left unremoved after the adhesion test".

Experimental Example  4: Bending durability

In the hard coating films of Examples 1 to 3 and Comparative Examples 1 to 3 were repeated 200,000 times the repeated bending test to fold and stretch the surface of the hard coating layer outward so that the distance between the film is 5mm, and evaluated as follows Are listed in Table 1 below.

<Evaluation Criteria>

○: no film break

×: film breaking

Interference prevention Pencil hardness Adhesion Bending durability Example 1 ○ 3H 100/100 ○ Example 2 ○ 3H 100/100 ○ Example 3 △ 3H 100/100 ○ Comparative Example 1 × 3H 100/100 ○ Comparative Example 2 × 3H 100/100 × Comparative Example 3 ○ 3H 100/100 ×

Referring to Table 1, when the difference in the refractive index of the cured product of the polyimide base film and the hard coating composition is less than 0.03 to satisfy the scope of the present invention (Examples 1 to 3), the difference in the refractive index is greater than 0.03 It can be seen that the generation of interference fringes is suppressed without deterioration of hardness and adhesiveness than in the case of departing from the scope of the present invention (Comparative Examples 1 to 2), and even if the difference in refractive index satisfies the scope of the present invention, the polyimide base film When using films other than (Comparative Examples 2 and 3), it can be confirmed that durability against repeated bending is poor.

Claims (7)

In the hard-coating film containing the hardened | cured material of a hard-coating composition on at least one surface of a polyimide base material, Hard substrate film, characterized in that the difference between the refractive index of the substrate; and the cured product of the hard coating composition; 0.03 or less. The method of claim 1, The hard coating composition is a hard coating film, characterized in that it comprises a high refractive resin. The method of claim 2, The hard coating film, characterized in that the refractive index after curing of the high refractive resin is 1.55 or more. The method of claim 2, The hard coating composition further comprises at least one selected from the group consisting of a translucent resin, a photoinitiator and a solvent. The method of claim 2, The content of the high refractive resin is a hard coating film, characterized in that contained in 10 to 100% by weight relative to the total 100% by weight of the hard coating composition comprising the same. An image display apparatus comprising the hard coat film of any one of claims 1 to 5. The method of claim 6, And the image display device is a flexible image display device.