JP2016188996A - Composition for forming hard coat and optical film and image display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for forming a hard coat that can achieve high hardness and excellent stain resistance.SOLUTION: The present invention relates to a composition for forming a hard coat that comprises, on its surface, silica nano particles including a fluorine-based silane substituent and an acrylic substituent, a photopolymerizable compound, a photopolymerization initiator, and a solvent to ensure better hardness of the silica nano particles, has an excellent antifouling property due to a substituent effect of the silica nano particles, and is excellent in compatibility with other components.SELECTED DRAWING: None

Description

The present invention relates to a composition for forming a hard coat, an optical film using the same, and an image display device, and more specifically, a composition capable of forming a hard coat excellent in hardness and antifouling property, and produced using the same. The present invention relates to an optical film and an image display device.

In recent years, a thin display device using a flat panel display device such as a liquid crystal display device or an organic light emitting diode display device has attracted attention. In particular, these thin display devices are realized in the form of touch screen panels, ranging from smart phones and tablet PCs to various wearable devices, Widely used in various smart devices characterized by portability.

These portable touch screen panel-based display devices have a display protection window cover on the display panel to protect the display panel from scratches and external shocks, and in most cases display Tempered glass is used as the window cover. Although the tempered glass for display is thinner than normal glass, it has characteristics of being strong and resistant to scratches.

However, tempered glass is not only suitable for reducing the weight of mobile devices, but also because it is vulnerable to external impacts, it is difficult to achieve an unbreakable property and is constant. It will not bend above the standard. For this reason, tempered glass is not suitable as a material for a flexible display having a bendable or foldable function.

Recently, active investigations have been made on optical plastic covers that have the strength and scratch resistance equivalent to tempered glass while ensuring flexibility and impact resistance. In general, as a material of an optical transparent plastic cover having flexibility as compared with tempered glass, polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polyacrylate (PAR), polycarbonate (PC ) And polyimide (PI). However, these polymer plastic substrates not only exhibit insufficient physical properties in terms of hardness and scratch resistance, but also have insufficient impact resistance compared to tempered glass used as a window cover for display protection. . For this reason, various attempts have been made to supplement the required physical properties by coating these plastic substrates with a composite resin composition.

In addition, the display protection window cover further includes an antifouling layer or the like that facilitates prevention and removal of contamination due to fingerprints or foreign matters from the viewpoint of improving image visibility. However, the antifouling layer that prevents surface contamination has a multilayer structure of inorganic fine particles with extremely high hydrophilicity, so it is easily contaminated during use, and it is not easy to remove contaminants. When removing pollutants using a different solvent, there is a problem in that the display surface is damaged.

Korean Published Patent No. 2013-74167 (Patent Document 1) discloses a plastic substrate.

Korean Published Patent No. 2013-74167

An object of this invention is to provide the composition for hard-coat formation which can implement | achieve high hardness and the outstanding stain | pollution property.

Moreover, an object of this invention is to provide an optical film provided with the hard-coat layer formed from the said composition for hard-coat formation.

Furthermore, an object of this invention is to provide an image display apparatus provided with the said optical film.

1. A composition for forming a hard coat, comprising silica nanoparticles having a fluorine-based silane substituent and an acrylic substituent on the surface, a photopolymerizable compound, a photopolymerization initiator, and a solvent.

（式中、前記ｎは１〜３の整数、ｍは１〜１５の整数、ｌは０〜１０の整数であり、
Ｒ_１及びＲ_２は、それぞれ独立に、炭素数１〜１０の直鎖又は分岐鎖のアルキル基、若しくは炭素数６〜１２のアリール基であり、
Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６及びＲ_７は、それぞれ独立に、水素原子、フッ素原子、又はフッ素で置換された炭素数１〜３のアルキル基であり、全てが水素原子であることはない。） 2. In the item 1, the composition for forming a hard coat, wherein the fluorine-based silane substituent is derived from a compound represented by the following chemical formula 1.

(In the formula, n is an integer of 1 to 3, m is an integer of 1 to 15, l is an integer of 0 to 10,
R ₁ and R ₂ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
R ₃ , R ₄ , R ₅ , R ₆ and R ₇ are each independently a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 3 carbon atoms substituted with fluorine, and all are hydrogen atoms. There is no. )

（式中、前記ｎは、それぞれ独立に１〜３の整数であり、ｍは、それぞれ独立に１〜１５の整数であり、
前記Ｒ_６、Ｒ_７、Ｒ_９、Ｒ_１０、Ｒ_１３及びＲ_１４は、それぞれ独立に、炭素数１〜１０の直鎖又は分岐鎖のアルキル基、若しくは炭素数６〜１２のアリール基であり、
Ｒ_８及びＲ_１２は、それぞれ独立に、少なくとも一つの（メタ）アクリルオキシ基で置換された炭素数１〜１０の直鎖又は分岐鎖のアルキル基であり、
Ｒ_１１は、炭素数１〜１０の直鎖又は分岐鎖のアルキレン基、炭素数６〜３０のシクロアルキレン基又はアリーレン基であり、
前記アルキレン基又はアリーレン基は、水酸基、カルボキシ基、若しくは炭素数１〜１０の直鎖又は分岐鎖のアルキル基で置換されてもよく、前記アルキル基は、エステル結合で中断されてもよく、
Ｒ_１５は、水素原子又はメチル基である。） 3. In the item 1, the acrylic substituent is a composition for forming a hard coat, which is derived from any of the compounds represented by the following chemical formulas 2 to 4.

(In the formula, each n is independently an integer of 1 to 3, m is each independently an integer of 1 to 15,
R ₆ , R ₇ , R ₉ , R ₁₀ , R ₁₃ and R ₁₄ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms. ,
R ₈ and R ₁₂ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms substituted with at least one (meth) acryloxy group;
R ₁₁ is a linear or branched alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 6 to 30 carbon atoms, or an arylene group,
The alkylene group or arylene group may be substituted with a hydroxyl group, a carboxy group, or a linear or branched alkyl group having 1 to 10 carbon atoms, and the alkyl group may be interrupted with an ester bond,
R ₁₅ is a hydrogen atom or a methyl group. )

4). In said item 1, the said silica nanoparticle is a composition for hard-coat formation whose average particle diameter is 10-100 nm.

5. In the item 1, the composition for forming a hard coat, wherein the silica nanoparticles are contained in an amount of 10 to 60 parts by weight with respect to a total of 100 parts by weight of the composition based on the solid content.

6). In the item 1, the photopolymerizable compound is selected from the group consisting of oligoester (meth) acrylate, oligoether (meth) acrylate, oligourethane (meth) acrylate, oligoepoxy (meth) acrylate, and oligomelamine (meth) acrylate. A composition for forming a hard coat, which is at least one selected from the group consisting of a selected oligomer and a monomer containing 1 to 6 (meth) acrylate functional groups.

7). The composition for hard coat formation according to item 1, wherein the photopolymerizable compound is contained in an amount of 10 to 90 parts by weight with respect to a total of 100 parts by weight of the composition based on the solid content.

8). The composition for hard coat formation according to item 1, wherein the photopolymerization initiator is at least one selected from the group consisting of an acetophenone photoinitiator and an aminoketone photoinitiator.

9. In said item 1, the said photoinitiator is a composition for hard-coat formation contained in 0.1-10 weight part with respect to a total of 100 weight part of a composition on the basis of solid content.

10. In the item 1, the hard coat forming composition, wherein the solvent is at least one selected from the group consisting of a ketone solvent, an acetate solvent, an alcohol solvent and a hydrocarbon solvent.

11. In said item 1, the said solvent is a composition for hard-coat formation contained in 5-80 weight part with respect to a total of 100 weight part of a composition.

12 The hard coat forming composition according to item 1, further comprising at least one additive selected from the group consisting of a leveling agent, a heat stabilizer, and an ultraviolet light stabilizer.

13. An optical film provided with the coat layer formed from the composition for hard-coat formation as described in any one of said item 1-12 on the at least one surface of a base film.

14 A polarizing plate comprising the optical film according to item 13.

15. The window film for touchscreens provided with the optical film of the said item 13.

16. An image display device comprising the optical film according to item 13.

The hard coat-forming composition of the present invention contains silica nanoparticles, exhibits excellent hardness, and is excellent in antifouling property due to the substituent effect on the surface of the silica nanoparticles.

Further, the silica nanoparticles are excellent in compatibility with other components, and can greatly improve the durability of the antifouling property of the hard coat film.

The present invention relates to a composition for forming a hard coat, and more specifically, includes silica nanoparticles having a fluorine-based silane substituent and an acrylic substituent on the surface, a photopolymerizable compound, a photopolymerization initiator, and a solvent. Thus, the present invention relates to a composition for forming a hard coat which ensures excellent hardness by silica nanoparticles, is excellent in antifouling property due to the substituent effect of silica nanoparticles, and is excellent in compatibility with other components.

The present invention will be described in detail below.

A technique of applying a silicone-based or fluorine-based additive to impart antifouling properties to the hard coat layer is a well-known technique. Usually, fluorine-based additives are superior to silicon-based in imparting antifouling properties, but their compatibility with other components in the composition is low, so their optical properties are reduced and antifouling properties are maintained. There was a problem that could not be realized.

<Composition for forming hard coat layer>
The composition for forming a hard coat layer of the present invention contains silica nanoparticles, a photopolymerizable compound, a photopolymerization initiator, and a solvent.

Silica nanoparticles The silica nanoparticles according to the present invention include a fluorine-based silane substituent and an acrylic substituent on the surface.

The silica nanoparticles are components that are applied to a hard coat film to achieve an excellent surface hardness. A fluorinated silane substituent is introduced on the surface of the particles, and the hard coat is characterized by the characteristics of a fluorine compound having a low surface energy. Since the antifouling effect of the layer can be expected and the compatibility with other compositions is excellent, the antifouling property can be realized continuously. Furthermore, by including a crosslinkable acrylic substituent at the same time, the mechanical strength can be realized in an appropriate range.

In the present invention, the fluorine-based silane substituent may be derived from a compound represented by the following chemical formula 1.

（式中、前記ｎは１〜３の整数、ｍは１〜１５の整数、ｌは０〜１０の整数であり、
Ｒ_１及びＲ_２は、それぞれ独立に、炭素数１〜１０の直鎖又は分岐鎖のアルキル基、若しくは炭素数６〜１２のアリール基であり、
Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６及びＲ_７は、それぞれ独立に、水素原子、フッ素原子又はフッ素で置換された炭素数１〜３のアルキル基であり、全てが水素原子であることはない。）

(In the formula, n is an integer of 1 to 3, m is an integer of 1 to 15, l is an integer of 0 to 10,
R ₁ and R ₂ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
R ₃ , R ₄ , R ₅ , R ₆ and R ₇ are each independently a hydrogen atom, a fluorine atom or an alkyl group having 1 to 3 carbon atoms substituted with fluorine, and all of them are hydrogen atoms. Absent. )

In the present invention, the acrylic substituent may be derived from any of the compounds represented by the following chemical formulas 2 to 4.

（式中、前記ｎは、それぞれ独立に１〜３の整数、ｍは、それぞれ独立に１〜１５の整数であり、
前記Ｒ_６、Ｒ_７、Ｒ_９、Ｒ_１０、Ｒ_１３及びＲ_１４は、それぞれ独立に、炭素数１〜１０の直鎖又は分岐鎖のアルキル基、若しくは炭素数６〜１２のアリール基であり、
Ｒ_８及びＲ_１２は、それぞれ独立に、少なくとも一つの（メタ）アクリルオキシ基で置換された炭素数１〜１０の直鎖又は分岐鎖のアルキル基であり、
Ｒ_１１は、炭素数１〜１０の直鎖又は分岐鎖のアルキレン基、炭素数６〜３０のシクロアルキレン基又はアリーレン基であり、
前記アルキレン基又はアリーレン基は、水酸基、カルボキシ基、又は炭素数１〜１０の直鎖又は分岐鎖のアルキル基で置換されてもよく、前記アルキル基は、エステル結合で中断されてもよく、
Ｒ_１５は、水素原子又はメチル基である。）

(In the formula, n is each independently an integer of 1 to 3, m is each independently an integer of 1 to 15,
R ₆ , R ₇ , R ₉ , R ₁₀ , R ₁₃ and R ₁₄ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms. ,
R ₈ and R ₁₂ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms substituted with at least one (meth) acryloxy group;
R ₁₁ is a linear or branched alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 6 to 30 carbon atoms, or an arylene group,
The alkylene group or arylene group may be substituted with a hydroxyl group, a carboxy group, or a linear or branched alkyl group having 1 to 10 carbon atoms, and the alkyl group may be interrupted with an ester bond,
R ₁₅ is a hydrogen atom or a methyl group. )

Method for introducing surface substituents of silica nanoparticles Silica nanoparticles containing fluorine-based silane substituents and acrylic substituents on the surface according to the present invention introduce hydroxyl groups present on the surface of silica nanoparticles into the substituents. It can be formed by reacting with a surface treatment agent.

The order of the surface treatment reaction is not particularly limited, but when the acrylic substituent is introduced first, the reaction of the fluorine-based silane substituent causes a competitive reaction with the hydroxyl group of the silica nanoparticles due to the reactivity of the acrylic substituent itself. Since a reaction can occur, it is preferable to introduce the fluorine-based silane substituent first.

First, the silica nanoparticles before introducing the substituent of the present invention can be used without particular limitation as long as they are usually used in this field, but dispersed in an organic solvent in order to facilitate the reaction described later. It is more preferable to use a colloidal silica sol.

Examples of commercially available silica nanoparticles include methyl ethyl ketone silica sol (MEK-ST, manufactured by Nissan Chemical, particle average size is 22 nm, silica content is 30%), silica powder particles (Aerosil TT600, Aerosil, particle average size 40 nm), Methyl isobutyl ketone silica sol (MIBK-ST, manufactured by Nissan Chemical, particle average size is 22 nm, silica content is 30%), isopropanol silica sol (IPA-ST, manufactured by Nissan Chemical, average particle size is 22 nm, silica content is 30%), etc. Is mentioned. These can be used alone or in admixture of two or more.

Solvents used for the production of the silica sol include alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, and the like An ester such as ethylene glycol monomethyl ether or diethylene glycol monobutyl ether; an aromatic hydrocarbon such as benzene, toluene or xylene; an amide such as dimethylformamide, dimethylacetamide or N-methylpyrrolidone; These can be used alone or in admixture of two or more.

Next, the above-mentioned silica nanoparticles can be reacted with the above-mentioned compound of Formula 1, and a fluorine-based silane substituent can be introduced by reaction with the hydroxyl groups on the surface of the silica nanoparticles.

Specific examples of the compound of Formula 1 include (3,3,3-trifluoropropyl) trimethoxysilane, (3,3,3-trifluoropropyl) triethoxysilane, and 4-methyl- (perfluorohexylethyl). ) Propyltrimethoxysilane, ((5S) -5,6,7,8,8,8-hexafluoro-5,7-bis (trifluoromethyl) octyl) trimethoxysilane, dodecylfluoro-heptyl-propyltrimethoxy Silane, ((5S) -5,6,7,8,8,8-hexafluoro-5,7-bis (trifluoromethyl) octyl) methyldimethoxysilane, dodecylfluoro-heptyl-propylmethyldimethoxysilane, (( 5S) -5,6,7,8,8,8-hexafluoro-5,7-bis (trifluoromethyl) octyl) Methyldiethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltrimethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane Etc. These can be used alone or in admixture of two or more.

Next, the silica nanoparticle having the fluorine-based silane substituent introduced therein is reacted with the compound selected from Chemical Formulas 2 to 4 described above, and the acrylic substituent is introduced by reaction with the hydroxyl group on the surface of the silica nanoparticle. Can do.

The compound of Chemical Formula 2 can be produced by a urethane reaction between an alkoxysilane isocyanate compound and a (meth) acrylate containing a hydroxyl group.

Examples of the alkoxysilane isocyanate compound include γ-isocyanatepropyltrimethoxysilane (GE Toshiba, A-Link 25), γ-isocyanatepropyltriethoxysilane (GE Toshiba, A-Link 35, Shin-Etsu). KBE-9007) and the like, but are not limited thereto.

Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, caprolactone-modified (meth) acrylate, polyethylene (propylene ) Glycol-modified (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and the like, but are not limited thereto.

At this time, the reaction between the alkoxysilane isocyanate compound and the (meth) acrylate having a hydroxyl group may proceed with an excessive amount of the (meth) acrylate having a hydroxyl group. Most preferably, it proceeds at a molar ratio of

The compound of Formula 3 can be produced by reacting the isocyanate group of the diisocyanate compound with an alkoxysilane mercaptan compound and a (meth) acrylate compound substituted with a hydroxyl group, respectively.

Examples of the diisocyanate compound include toluene-2,4-diisocyanate and isomers, xylene diisocyanate, isophorone diisocyanate, tetramethylxylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, 2,2-bis-4′-propane isocyanate, 6-isopropyl-1,3-phenyl diisocyanate, bis (2-isocyanatoethyl) -fumarate, 1,6-hexane diisocyanate, 4,4′-biphenylene diisocyanate, 3,3′-dimethylphenylene diisocyanate, 3,3′- Dimethyl-4,4′-diphenylmethane diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4 -Xylene diisocyanate, 1,3-xylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate and the like.

Examples of the alkoxysilane mercaptan compounds include 3-mercaptopropylmethyldimethoxysilane (manufactured by Shin-Etsu Co., Ltd., KBM-802), 3-mercaptopropyl trimethoxysilane (GE Toshiba Corporation, A-189, Shin-Etsu Co., Ltd., KBM- 803) and the like, but are not limited thereto.

The same compound as the compound used at the time of manufacture of Chemical formula 2 can be used for the (meth) acrylate containing the hydroxyl group.

At this time, the molar ratio of the diisocyanate compound and the hydroxyl group-containing (meth) acrylate is preferably an excess of the hydroxyl group-containing (meth) acrylate, and a molar ratio of 1: 1.05 to 1: 1.2. Is most preferable.

Examples of the compound of Formula 4 include 3-methacryloxypropylmethyldimethoxysilane (manufactured by Shin-Etsu Co., Ltd., KBM-502), 3-methacryloxyoxypropyltrimethoxysilane (manufactured by Shin-Etsu Co., Ltd., KBM-503), 3- Methacryloxypropylmethyldiethoxysilane (KBE-502 manufactured by Shin-Etsu Co., Ltd., A-174 manufactured by Toshiba), 3-methacryloxypropyl triethoxysilane (KBE-503 manufactured by Shin-Etsu Co., Ltd., Y manufactured by GE Toshiba Corp.) -9936), 3-acryloxypropylmethyldimethoxysilane (manufactured by Shin-Etsu Co., Ltd., KBE-5103) and the like, but are not limited thereto.

The introduction reaction of the substituent can be performed in the form of a silane sol in which silica nanoparticles are dispersed in a solvent, and an acid or a base may be used as a catalyst in the reaction.

Acids used as reaction catalysts include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid, methanesulfonic acid, toluenesulfonic acid, phthalic acid, malonic acid, formic acid, acetic acid, oxalic acid, methacrylic acid, acrylic acid, itacone Examples of the base include ammonium salts such as tetramethylammonium chloride and tetrabutylammonium chloride, water-soluble ammonia; primary, secondary or tertiary aliphatic amines such as diethylamine, triethylamine, and the like. Dibutylamine and cyclohexylamine; aromatic amines such as pyridine; sodium hydroxide, potassium hydroxide; tertiary ammonium hydroxides such as tetramethylammonium hydroxide, tetrabutylammonium hydroxide and the like.

Further, a dehydrogenating agent can be further used for the purpose of promoting the reaction. Specific examples of the dehydrogenating agent include inorganic compounds such as zeolite, anhydrous silica and anhydrous alumina, and organic compounds such as methyl orthoformate, ethyl orthoformate, tetraethoxymethane, and tetrabutoxymethane.

Although the magnitude | size of the silica nanoparticle which has a substituent on the surface by this invention is not specifically limited, For example, an average particle diameter may be 10-100 nm, Preferably it may be 15-50 nm. When the particle size is in the above range, the effect of preventing curing shrinkage can be realized, excellent hardness can be ensured, and appropriate transparency can be realized, which is more preferable.

The content range of the silica nanoparticles according to the present invention is not particularly limited. For example, the silica nanoparticles may be included in an amount of 10 to 60 parts by weight based on the solid content with respect to 100 parts by weight of the total composition. If it is included in the above range, the effect of preventing curing shrinkage can be realized, excellent hardness can be ensured, and appropriate transparency can be realized, which is more preferable.

Photopolymerizable compound The photopolymerizable compound according to the present invention includes, for example, a compound having 4 or more polymerizable unsaturated groups in the molecule, and 1 to 3 polymerizable unsaturated groups in the molecule. The compound which has may be sufficient and these can be used individually or in mixture of 2 or more types.

The compound having four or more polymerizable unsaturated groups in the molecule is a component that increases the crosslink density during curing so that excellent hardness of the hard coat layer can be realized.

Specific examples include monomers containing 1 to 6 (meth) acrylate functional groups such as dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrile. Methylolpropane tetra (meth) acrylate, ethylene oxide or propylene oxide additive compound of the above (meth) acrylate; oligoester (meth) acrylate having 4 or more (meth) acryloyl groups in the molecule, oligoether (meth) acrylate, oligo Examples include urethane (meth) acrylate, oligoepoxy (meth) acrylate, and oligomelamine (meth) acrylate.

Among these, dipentaerythritol hexa (meth) acrylate, dipentaerythritol hydroxypenta (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and the like are preferable.

As an example of a commercial item, Aronix M-400, M-408, M-450 (above, Toagosei Co., Ltd. make), KAYARAD D-310, D-330, DPHA, DPCA-20, DPCA-30, DPCA-60 DPCA-120, SR-295, SR-355, SR-399E, SR-494, SR-9041 (above, manufactured by Nippon Kayaku Co., Ltd.), Light Acrylate PE-4A, DPE-6A, DTMP-4A (above, Kyoeisha Chemical Co., Ltd.).

The compound having 1 to 3 polymerizable unsaturated groups in the molecule is a component that improves the curling characteristics of the cured product without reducing the crosslinking density upon curing.

As the polymerizable unsaturated group, a compound having a (meth) acryloyl group or a vinyl group is preferable. Specific examples thereof include (meth) acrylic acid esters, N-vinyl compounds, vinyl-substituted aromatic compounds, vinyl ethers, and vinyl esters.

As (meth) acrylic acid ester, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, glycerol tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, ethylene glycol di (Meth) acrylate, propylene glycol (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl Glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, bis (2-hydroxy ester) L) Isocyanurate di (meth) acrylate, poly (meth) acrylate with ethylene oxide or propylene oxide added to the (meth) acrylic acid ester; oligoester (meth) acrylate having 1 to 3 (meth) acryloyl groups in the molecule , Oligoether (meth) acrylic acid ester, oligourethane (meth) acrylic acid ester, oligoepoxy (meth) acrylic acid ester; hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, Products added with ethylene oxide or propylene oxide to (meth) acrylic acid ester; mono (meth) acrylic acid ester, iso-octyl (meth) acrylate, iso-decyl (meth) acrylate, stearyl Meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (meth) acrylate. Examples of the N-vinyl compound include N-vinyl pyrrolidone, N-vinyl caprolactam, N-vinyl phthalimide, and N-vinyl succinimide. Examples of the vinyl-substituted aromatic product include styrene, divinylbenzene, chloromethylstyrene, hydroxystyrene, α-methylstyrene, bromomethylstyrene, and tribromomethylstyrene. Examples of the vinyl ether include diethylene glycol monomethyl vinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether. Examples of the vinyl ester include vinyl acetate, vinyl propionate, and vinyl benzoate.

As an example of a commercial item, brand names Aronix M-101, M-102, M-110, M-111, M-113, M-117, M-120, M-150, M-156, M-208, M-210, M-215, M-220, M-225, M-233, M-240, M-245, M-260, M-270, M-305, M-309, M-310, M- 315, M-320, M-350, M-360 (above, manufactured by Toagosei Co., Ltd.), KAYARAD TC-110S, TC-120S, R-128, HDDA, NPGDA, TPGDA, PEG400DA, MANDA, HX-220, HX -620, R-551, R-712, R-167, TMPTA, KS-HDDA, KS-TPGDA, KS-TMPTA, SR-256, SR-257, SR-285, R-335, SR-339A, SR-395, SR-440, SR-489, SR-495, SR-504, SR-111, SR-212, SR-213, SR-230, SR-259, SR- 268, SR-272, SR-344, SR-349, SR-601, SR-602, SR-610, SR-9003, SR-368, SR-415, SR-444, SR-454, SR-492, SR-499, SR-502, SR-9020, SR-9035 (manufactured by Nippon Kayaku Co., Ltd.) and the like.

In the present invention, the content of the photopolymerizable compound is not particularly limited, but may be 10 to 90 parts by weight, preferably 30 to 85 parts by weight with respect to 100 parts by weight of the total composition. When the above range is satisfied, the hardness of the cured product is excellent and the occurrence of curling can be reduced.

Photopolymerization initiator The photopolymerization initiator according to the present invention is not particularly limited as long as it can form radicals by light irradiation.

Examples of the photopolymerization initiator include acetophenone photoinitiators and aminoketone photoinitiators. These can be used alone or in combination of two or more.

Examples of the acetophenone photoinitiator include 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1- ON, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2 -Hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone and the like.

Examples of the aminoketone photoinitiator include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 2-methyl-1- [4- (methoxy) phenyl] -2-morpholino. Propanone-1,2-methyl-1- [4- (2-hydroxyethoxy) phenyl-2-morpholinopropanone-1,2-methyl-1- [4- (dimethylamino) phenyl-2-morpholinopro Panone-1,2-methyl-1- [4- (diphenylamino) phenyl] -2-morpholinopropanone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 3,6-bis (2-methyl-2-morpholinopropionyl) -9-N-octylcarbazole and the like can be mentioned.

Examples of commercially available products include Irgacure 184, 127, 500, 2959, 369, 907, and Darkure 1173 (manufactured by BASF).

When both the acetophenone photoinitiator and aminoketone photoinitiator are used, the weight ratio is preferably 1: 9 to 9: 1, and more preferably 4: 6 to 8: 2.

In this invention, content of a photoinitiator is although it does not specifically limit, 0.1-10 weight part may be sufficient with respect to a total of 100 weight part of a composition on the basis of solid content. If the said range is satisfy | filled, it will be excellent in the hardness of hardened | cured material and can implement | achieve a uniform hardening density in the whole hardening layer.

Solvent The solvent according to the present invention can be used without particular limitation as long as it can dissolve or disperse the aforementioned components.

Specific examples include alcohols (methanol, ethanol, isopropanol, butanol, propylene glycol methoxy alcohol, etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, etc.), acetates (methyl acetate) , Ethyl acetate, butyl acetate, propylene glycol methoxyacetate), cellosolve (methyl cellosolve, ethyl cellosolve, propyl cellosolve, etc.), hydrocarbon (normal hexane, normal heptane, benzene, toluene, xylene, etc.) and the like. These can be used alone or in admixture of two or more.

In the present invention, the content of the solvent is not particularly limited, but may be 5 to 80 parts by weight, preferably 30 to 60 parts by weight with respect to 100 parts by weight of the total composition.

Additives The composition for forming a hard coat according to the present invention may further contain additives such as a leveling agent, an ultraviolet stabilizer, and a heat stabilizer, if necessary, in addition to the components described above.

The leveling agent is added in order to improve the smoothness and applicability of the coating film when the composition is applied, and a silicon leveling agent, a fluorine leveling agent, an acrylic leveling agent, or the like can be used. Commercially available products of the leveling agent include BYK-323, BYK-331, BYK-333, BYK-337, BYK-373, BYK-375, BYK-377, BYK-378, manufactured by BYK-Chem Corp., TEGO Glide 410 manufactured by TEGO. , 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 2100, Rad 2500, 3M FC-4430, FC-4432, etc. can be used.

The UV stabilizer is added to prevent the surface of the coating from being discolored or easily broken by continuous UV irradiation, and plays a role in blocking or absorbing UV rays. The UV stabilizers can be classified into absorbers, quenchers, and hindered amine light stabilizers (HALS) according to the mechanism of action. For example, phenyl salicylates (Phenyl Salicylates, absorbent), benzophenone (Benzophenone, absorbent), benzotriazole (Benzotriazole, absorbent), nickel derivative (quenching agent), free radical scavenger, and the like.

As the heat stabilizer, polyphenol-based, phosphite-based, and lactone-based heat stabilizers can be used. The ultraviolet stabilizer and the heat stabilizer can be mixed and used in an appropriate content at a level that does not affect the ultraviolet curability.

The additive is preferably used in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the total composition.

<Optical film>
Moreover, this invention provides the optical film provided with the hard-coat layer formed from the said composition for hard-coat layer formation.

The optical film of this invention contains the base film provided with the hard-coat layer formed from the said composition at least on one surface.

The base film can be used without particular limitation as long as it is a transparent polymer film. For example, triacetyl cellulose, acetyl cellulose butyrate, ethylene-vinyl acetate copolymer, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, polyester, Polystyrene, polyamide, polyetherimide, polyacryl, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, Polyethersulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene It may be a film formed from a polymer such as carbonate. These polymers can be used alone or in admixture of two or more.

Among base film, crystalline polymer base film, engineering plastic base, difficult to impart adhesion after coating, polymer base film whose surface is changed to hydrophilic by hydrolysis or saponification are usually used. When the composition for forming a hard coat layer is used, it is difficult to increase the adhesion, or the mechanical properties may be lowered due to this. However, the above-described composition for forming a hard coat layer of the present invention can realize excellent adhesion without deteriorating mechanical properties even for these base films.

The base film may be subjected to a surface treatment such as plasma treatment or corona treatment in order to improve the adhesion with the hard coat layer.

The hard coat layer is formed by applying a hard coat layer forming composition on a base film and curing it. For coating, slit coating method, knife coating method, spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, spray coating method, screen Known methods such as a printing method, a gravure printing method, a flexographic printing method, an offset printing method, an inkjet coating method, a dispenser printing method, a nozzle coating method, and a capillary coating method can be used.

The thickness of a hard-coat layer is not specifically limited, For example, 5-100 micrometers may be sufficient. When the thickness is within the above range, excellent hardness and flexibility can be exhibited, and the curling phenomenon can be prevented.

Moreover, this invention relates to the polarizing plate provided with the said optical film, and the window film for touchscreens.

<Image display device>
Furthermore, this invention provides the image display apparatus provided with the said hard coat film.

Since the hard coat film of the present invention is excellent in hardness and flexibility, it can be used, for example, as a window cover on the outermost surface of an image display device, and can be suitably applied to a flexible image display device.

The image display device may be various image display devices such as a normal liquid crystal display device, an electroluminescence display device, a plasma display device, and a field emission display device.

In the following, preferred examples are presented to assist the understanding of the present invention, but these examples merely illustrate the present invention and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments within the scope of the technical idea, and such changes and modifications are within the scope of the appended claims. Of course it belongs.

Synthesis Example-Synthesis of Surface Treatment Agent
Synthesis Example 1: Surface treatment agent having an acrylic substituent (a1)
In a 2 L three-necked flask equipped with a mechanical stirrer, heating mantel, and cooling tube, 222 parts of IPDI (isophorone diisocyanate, Bayer), KBM-803 (manufactured by Shin-Etsu Co., Mercaptopropyltrimethoxysilane) A solution obtained by mixing 157 parts and 0.1 part of dibutyltin dilaurate as a catalyst was stirred in dry air at 50 ° C. for 1 hour.

The mixture had self-heating, and the reaction was carried out with stirring for another 3 hours while maintaining the reaction temperature at 60 ° C. Thereafter, the reaction temperature was lowered to 30 ° C., 715 parts of M340 (manufactured by Miwon Specialty Chemical, pentaerythritol triacrylate) was added, and the mixture was further stirred at 60 ° C. for 3 hours while heating to obtain a specific organic compound. It was.

Infrared absorption spectrum of the product (FT-IR) has disappeared absorption peak at 2260 cm ^-1 which is characteristic to the 2550 cm ^-1, and an isocyanate group is characterized by a mercapto group of the starting material in, [- O-C (= O) -NH-] and [-S-C (= O) 1660cm -1 , which is characteristic to a carbonyl group in -NH-], the absorption peak at 1720 cm ^-1 which is characteristic to an acryloyl group were observed. This is a specific organic compound (a1) having an acryloyl group, [—O—C (═O) —NH—] group and [—S—C (═O) —NH—] group as polymerizable unsaturated groups. Is shown.

Synthesis Example 2: Surface treatment agent having acrylic substituent (a2)
In a 2 L three-necked flask equipped with a mechanical stirrer, a heating mantle, and a condenser tube, 247.4 parts of KBE-9007 (isocyanatopropylethoxysilane, manufactured by Shin-Etsu Co., Ltd.) and M340 (manufactured by Miwon Specialty Chemical Co., pentaerythritol triacrylate) ) A mixture of 656 parts and 0.1 part of dibutyltin dilaurate as a catalyst was reacted for 6 hours while stirring in dry air at 60 ° C. to obtain a specific organic compound.

In the infrared absorption spectrum (FT-IR) of the product, the absorption peak disappears at 2260 cm ⁻¹ , which is characterized by the isocyanate group in the raw material, and it is characterized by [—O—C (═O) —NH—] and carbonyl group. 1660 cm ^-1 is, as well as absorption peak at 1720 cm ^-1 which is characteristic to an acryloyl group were observed. This shows the production | generation of the specific organic compound (a2) which has an acryloyl group and a [-O-C (= O) -NH-] group as a polymerizable unsaturated group.

Production Example-Synthesis of Silica Nanoparticles
(1) Production Example 1
5.7 parts by weight of Synthesis Example 1, 3 parts by weight of SiSiB (R) PC9757 (Tridecafluorooctyltrimethoxy silane, manufactured by SiSiB Silicone), methyl ethyl ketone silica sol (MEK-ST, manufactured by Nissan Chemical Industries, number average particle size: 0.022 μm, silica content : 30%) A solution obtained by mixing 91.3 parts by weight, 0.2 parts by weight of isopropyl alcohol, and 0.1 parts by weight of distilled water was stirred at 80 ° C. for 3 hours in a nitrogen atmosphere to obtain methyl orthoformate 1. 4 parts by weight were added. While heating the mixture at the same temperature, the mixture was further stirred for 1 hour to obtain a colorless and transparent dispersion of silica sol (A1) surface-treated with a fluorine silane substituent.

2 g of the dispersion was placed on an aluminum pan, weighed and dried on a hot plate at 120 ° C. for 1 hour, and then the weight was confirmed to confirm that the solid content was 36%.

(2) Production Example 2
A colorless and transparent dispersion of silica sol (A2) surface-treated with a fluorine silane substituent was obtained in the same manner as in Production Example 1 except that 5.7 parts by weight of Synthesis Example 2 was used.
2 g of the dispersion was placed on an aluminum dish and weighed, dried on a hot plate at 120 ° C. for 1 hour, and then checked for weight to confirm that the solid content was 35%.

(3) Production Example 3
The same as Production Example 1 except that 3.7 parts by weight of 3-acryloxypropyltriethoxysilane (manufactured by Shin-Etsu Co., Ltd., KBE-5103) and 5 parts by weight of SiSiB (R) PC9757 (manufactured by Tridecafluorooctyltrimethoxysilane, SiSiB Silicone) were used. Thus, a colorless transparent dispersion of silica sol (A3) surface-treated with a fluorine silane substituent was obtained.
2 g of the dispersion was placed on an aluminum dish and weighed and dried on a hot plate at 120 ° C. for 1 hour, and then the weight of the substance was confirmed to confirm that the solid content was 37%.

(4) Production Example 4
Manufacture except that 8.7 parts by weight of 3-acryloxypropyltriethoxysilane (manufactured by Shin-Etsu Co., Ltd., KBE-5103) was used instead of Synthesis Example 1 and SiSiB® PC9757 (Tridecafluorooctyltrimethoxysilane, manufactured by SiSiB Silicone). In the same manner as in Example 1, a colorless and transparent dispersion of silica sol (A5) surface-treated with an acrylic substituent was obtained.
2 g of the dispersion was placed on an aluminum pan, weighed and dried on a hot plate at 120 ° C. for 1 hour, and then the weight of the substance was confirmed to confirm that the solid content was 35%.

(5) Production Example 5
Instead of Synthesis Example 1, surface treatment was performed with a fluorine silane substituent in the same manner as in Production Example 1 except that only 8.7 parts by weight of SiSiB (R) PC9757 (Tridecafluorooctyltrimethoxysilane, manufactured by SiSiB Silicone) was used. A colorless and transparent dispersion of silica sol (A4) was obtained.
2 g of the dispersion was placed on an aluminum dish and weighed and dried on a hot plate at 120 ° C. for 1 hour, and then the weight of the substance was confirmed to confirm that the solid content was 36%.

Examples and comparative examples According to the components and contents shown in Table 1 below, compositions for forming a hard coat were produced. The solvent was added so that the total composition would satisfy 100 parts by weight.

Test method The hard coat forming compositions of Examples and Comparative Examples were applied to an 80 μm optical polyimide film (Mitsubishi Gas Chemical Co., Ltd., 100 μm, L-3430) using a bar coater. A wet coating was formed. Then, after drying in an oven at 80 ° C. for 1 minute, after irradiation at 500 mJ / cm ² using a conveyor type high-pressure mercury lamp, a hard coat film is manufactured so that the final hard coat layer has a thickness of 4 μm. did.

(1) Evaluation of surface smoothness By illuminating the surface on which the hard coat layers of the films of Examples and Comparative Examples were applied with electric light and observing from a direction of inclination of 20 to 30 °, The presence or absence of unevenness and wrinkles that were considered to be caused by uniformity (presence / absence of micro-aggregation) and surface properties of the hard coat layer was confirmed.
<Evaluation criteria>
A: The surface layer has no micro-aggregation and is uniform, and the hard coat layer has no irregularities or wrinkles.
B: Although micro-aggregation is observed in the surface layer, it is very slight, and irregularities and wrinkles are not confirmed in the hard coat layer.
C: Microaggregation is observed in the surface layer, but no irregularities or wrinkles are observed in the hard coat layer.
D: Micro-aggregation is remarkably observed in the surface layer, and irregularities and wrinkles are confirmed in the hard coat layer.

(2) Evaluation of pencil hardness Pencil hardness was measured by applying a load of 500 g to the films of Examples and Comparative Examples using a pencil hardness tester (PHT, manufactured by Korea Sokbo Science Co., Ltd.). For the pencil, Mitsubishi products were used, and the experiment was conducted 5 times for each pencil hardness, and the maximum pencil hardness at which the scratch was shown 1 time or less was defined as the pencil hardness of the hard coat layer.

(3) Evaluation of scratch resistance The film of the example and the comparative example was reciprocated 10 times under 1 kg / (2 cm × 2 cm) using a steel wool tester (WT-LCM100, manufactured by Korea Protect). Exercise and test for scratch resistance. # 0000 was used as the steel wool.
<Evaluation criteria>
S: 0 scratches A: 1-10 scratches B: 11-20 scratches C: 21-30 scratches D: 31 or more scratches

(4) Evaluation of adhesion The surface of the film of Examples and Comparative Examples, on which the hard coat layer was applied, was cut at 11 mm intervals at 1 mm intervals to create 100 regular squares. . Thereafter, a peel test was performed three times using a tape (CT-24, manufactured by Nippon Nichiban Co., Ltd.), and the average value of the number of squares peeled off was recorded.
Adhesion was recorded as follows.
Adhesiveness = n / 100
(N: the number of squares not peeled out of the whole squares, 100: the number of whole squares)
In addition, when neither peeled, it recorded on 100/100.

(5) Evaluation of curl A sample cut to A4 size (29.7 × 21.0 cm) was placed on a flat glass plate with the surface coated with the hard coat layer of the films of Examples and Comparative Examples on top. The distance away from the square glass plate was measured at 25 ° C. and 50% RH, and the average value was taken as the measured value.
<Evaluation criteria>
Very good: 0-15mm
Good: Over 15 mm to 30 mm
Defect: over 30mm to 50mm
Very bad: over 50mm

(6) Evaluation of contact angle with water After dropping water droplets on the surface of the films of Examples and Comparative Examples at room temperature (25C), a contact angle measuring device (CAM100 manufactured by KSV) was used after 1 minute. The contact angle with respect to water droplets was measured. For the contact angle, the left and right contact angles of water droplets were measured five times with the same sample, and the average value was used.

(7) Evaluation of antifouling property The film of the example and the comparative example was scribbled on the coating surface with a black oil pen made by Monami, and the surface was cleaned with clean paper (ULTIMAII, HANSONG) Was wiped lightly 10 times and evaluated as follows.
<Evaluation criteria>
A: Characters cannot be written and the surface can be easily wiped off (very good antifouling property)
B: Cannot write characters, but surface is not easy to wipe off (good antifouling property)
C: Characters can be written well, but the surface can be easily wiped (poor antifouling property)
D: Characters can be written well, and wiping the surface is not easy (antifouling property is extremely poor)

As can be seen from Table 2 above, the examples using the silica nanoparticles according to the present invention were able to ensure both mechanical properties and antifouling properties at the same time.

Moreover, Example 1 using the silica nanoparticle dispersion liquid of Production Example 1 has improved durability by including an aromatic ring in the molecule, and realizes the most excellent pencil hardness compared with the same content. I was able to confirm that.

However, in the case of a comparative example using silica nanoparticles that do not contain a fluorine-based substituent, it is difficult to achieve antifouling properties, and mechanical properties differ depending on the content of silica sol, but the effect was lower than in the examples. .

Further, in Comparative Example 9 using only the fluorine-based substituent, the antifouling property showed a level equivalent to that of the Example, but the pencil hardness was 2H, and it is judged that it is not suitable for the hard coat.

Claims (16)

A composition for forming a hard coat, comprising silica nanoparticles having a fluorine-based silane substituent and an acrylic substituent on the surface, a photopolymerizable compound, a photopolymerization initiator, and a solvent. The composition for forming a hard coat according to claim 1, wherein the fluorine-based silane substituent is derived from a compound represented by the following chemical formula 1.

(In the formula, n is an integer of 1 to 3, m is an integer of 1 to 15, l is an integer of 0 to 10,
R ₁ and R ₂ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
R ₃ , R ₄ , R ₅ , R ₆ and R ₇ are each independently a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 3 carbon atoms substituted with fluorine, and all are hydrogen atoms. There is no. ) The composition for forming a hard coat according to claim 1, wherein the acrylic substituent is derived from any one of compounds represented by the following chemical formulas 2 to 4.

(In the formula, each n is independently an integer of 1 to 3, m is each independently an integer of 1 to 15,
R ₆ , R ₇ , R ₉ , R ₁₀ , R ₁₃ and R ₁₄ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms. ,
R ₈ and R ₁₂ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms substituted with at least one (meth) acryloxy group;
R ₁₁ is a linear or branched alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 6 to 30 carbon atoms, or an arylene group,
The alkylene group or arylene group may be substituted with a hydroxyl group, a carboxy group, or a linear or branched alkyl group having 1 to 10 carbon atoms, and the alkyl group may be interrupted with an ester bond,
R ₁₅ is a hydrogen atom or a methyl group. ) The composition for forming a hard coat according to claim 1, wherein the silica nanoparticles have an average particle diameter of 10 to 100 nm. The composition for forming a hard coat according to claim 1, wherein the silica nanoparticles are contained in an amount of 10 to 60 parts by weight with respect to a total of 100 parts by weight of the composition based on the solid content. The photopolymerizable compound is an oligomer selected from the group consisting of oligoester (meth) acrylate, oligoether (meth) acrylate, oligourethane (meth) acrylate, oligoepoxy (meth) acrylate, oligomelamine (meth) acrylate, 2. The composition for forming a hard coat according to claim 1, which is at least one selected from the group consisting of monomers containing 1 to 6 (meth) acrylate functional groups. The said photopolymerizable compound is a composition for hard-coat formation of Claim 1 contained by 10-90 weight part with respect to a total of 100 weight part of a composition on the basis of solid content. The composition for forming a hard coat according to claim 1, wherein the photopolymerization initiator is at least one selected from the group consisting of an acetophenone photoinitiator and an aminoketone photoinitiator. The said photoinitiator is a composition for hard-coat formation of Claim 1 contained by 0.1-10 weight part with respect to a total of 100 weight part of a composition on the basis of solid content. 2. The composition for forming a hard coat according to claim 1, wherein the solvent is at least one selected from the group consisting of a ketone solvent, an acetate solvent, an alcohol solvent, and a hydrocarbon solvent. The said solvent is a composition for hard-coat formation of Claim 1 contained by 5-80 weight part with respect to a total of 100 weight part of a composition. The composition for forming a hard coat according to claim 1, further comprising at least one additive selected from the group consisting of a leveling agent, a heat stabilizer, and an ultraviolet light stabilizer. An optical film provided with the coating layer formed from the composition for hard-coat formation as described in any one of Claims 1-12 in at least one surface of a base film. A polarizing plate comprising the optical film according to claim 13. A window film for a touch panel, comprising the optical film according to claim 13. An image display device comprising the optical film according to claim 13.