KR20160002171A - Hard Coating Composition and Hard Coating Film Using the Same - Google Patents

Abstract

The present invention provides a hard coating composition and a hard coating film on which a hard coating layer is formed by spreading the composition. The hard coating composition of the present invention comprises: a urethane acrylate oligomer; a photocurable material; and a photopolymerization initiator, wherein the urethane acrylate oligomer further comprises: isocyanate; a polyol compound; and an acrylate monomer. In addition, the polyol compound comprises 30-100 wt% of an aromatic acrylate monomer with respect to the total weight of the polyol compound based on solid, and the acrylate monomer comprises 30-100 wt% of the aromatic acrylate monomer with respect to the total weight of the acrylate monomer based on solid.

Description

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

The present invention relates to a hard coating composition and a hard coating film using the hard coating composition, and more particularly, to a hard coating composition for producing a hard coating film for display protection and a hard coating film for display protection using the hard coating composition will be.

In general, important commercial products, including optical functional products such as windows for various electronic products, touch screens for computers, lenses for automobiles, automobile sunroofs, optical screens, light guide plates and LED front plates have been widely used as glass in the past, And the defect rate in the processing of the product was considerably high.

Thermoplastic and thermosetting polymers have been used to replace them, and they have been used to form various structures because of their high hardness and high light transmittance.

However, since many thermosetting and thermoplastic polymers as described above are excellent in stiffness, dimensional stability, transparency, and impact resistance, structures made from the above polymers are less prone to scratches, abrasion, hardness And the like.

Therefore, it is used by using tempered glass or by coating a plastic surface with a wear-resistant hard coat layer to protect the resin products from physical or mechanical damage.

As a composition for forming the hard coat layer, Korean Patent Laid-Open No. 10-2013-0135151 discloses a binder for a binder comprising a 3- to 6-functional acrylate monomer; Inorganic fine particles; Photoinitiators; And an organic solvent, wherein a weight ratio of the solid content: the organic solvent to the solid content including the binder monomer, the inorganic fine particles, and the photoinitiator is from 70:30 to 99: 1 .

However, when the conventional hard coat layer composition as described above is applied to a plastic surface, the weather resistance is poor and the yellow hardness is high and the hardness is excellent, but the mechanical strength (tensile strength and elongation) such as abrasion resistance, And exposed to various problems such as fragility which is easy to be broken after coating, resulting in defective product processing.

Korean Patent Publication No. 10-2013-0135151

The present invention has been made in order to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a composition for hard coating of a hard coating film for display protection, which has improved physical properties such as hardness, adhesion, flexural resistance and abrasion resistance, In particular, a hard coating composition capable of forming a hard coating layer having a high refractive index.

The present invention also aims to provide a hard coat film comprising a hard coat layer made of the hard coat composition and having a high refractive index with improved chemical properties such as hardness, adhesion, flexural resistance and abrasion resistance, and chemical resistance .

According to the present invention,

A urethane acrylate oligomer, a photocurable material and a photopolymerization initiator,

The urethane acrylate oligomer comprises an isocyanate, a polyol compound and an acrylate monomer,

Wherein the polyol compound comprises an aromatic polyol compound in an amount of 30 to 100 wt% based on the total weight of the polyol compound based on the solid content, and the acrylate monomer has an aromatic acrylate monomer in an amount of 30 to 100 wt% based on the total weight of the acrylate monomer, By weight based on 100% by weight of the hard coat composition.

In addition,

There is provided a hard coat film comprising a hard coat layer formed by applying the hard coat composition on one side or both sides of a substrate.

The hard coating composition according to the present invention is excellent in physical properties such as hardness, adhesion, bending resistance, abrasion resistance, and chemical resistance when it is coated on the surface of a plastic substrate and is environmentally friendly, And in particular, a hard coating layer having a high refractive index can be formed.

The hard coating film prepared using the hard coating composition is excellent in physical properties such as hardness, adhesion, bending resistance and abrasion resistance of the hard coating layer, has excellent chemical resistance, and has a high refractive index. . Particularly, it is possible to prevent breakage, which is a disadvantage of tempered glass, and to lighten the product, so that it can be variously applied to a product using conventional tempered glass.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is well known and commonly used in the art.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

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

The present invention relates to a composition comprising a urethane acrylate oligomer, a photocurable material and a photopolymerization initiator,

The urethane acrylate oligomer comprises an isocyanate, a polyol compound and an acrylate monomer,

Wherein the polyol compound comprises an aromatic polyol compound in an amount of 30 to 100 wt% based on the total weight of the polyol compound based on the solid content, and the acrylate monomer has an aromatic acrylate monomer in an amount of 30 to 100 wt% based on the total weight of the acrylate monomer, To 100% by weight of the hard coat composition.

When the aromatic polyol compound is contained in an amount of less than 30 wt% based on the total weight of the polyol compound based on the solid content, or when the aromatic acrylate monomer is contained in an amount of less than 30 wt% based on the total weight of the acrylate monomer based on the solid content, It is difficult to expect improvement in chemical resistance and refractive index of the composition.

Preferably, the polyol compound contains an aromatic polyol compound in an amount of 30 to 60 wt% based on the total weight of the polyol compound based on the solid content, and the acrylate monomer is an aromatic acrylate based on the total weight of the acrylate monomer, It is preferable that the monomer is contained in an amount of 50 to 80% by weight.

More preferably, the polyol compound comprises an aromatic polyol compound in an amount of 35 to 45% by weight based on the solid content of the polyol compound, and the acrylate monomer is an aromatic acrylate based on the total weight of the acrylate monomer, It is preferable to contain 60 to 70% by weight of the monomer. If the amount of the aromatic polyol compound exceeds 45% by weight, polymerization of the urethane acrylate may be difficult and gelation may occur. If the aromatic acrylate monomer is more than 70% by weight, viscosity may increase and handling may be difficult have.

The present invention is characterized in that the aromatic polyol compound and the aromatic acrylate monomer are used together to improve the chemical resistance and refractive index as well as other physical properties of the hard coating composition.

The hard coating composition may contain 20 to 60 parts by weight of a photocurable material and 3 to 10 parts by weight of a photopolymerization initiator based on 100 parts by weight of urethane acrylate oligomer based on solid content. If the photo-curable material is contained in an amount of less than 20 parts by weight based on 100 parts by weight of the urethane acrylate oligomer, hardness suitable for the hard coat layer can not be obtained. If it exceeds 60 parts by weight, There is a problem of poor sex. If the photopolymerization initiator is contained in an amount of less than 3 parts by weight based on 100 parts by weight of the urethane acrylate oligomer, photo-curing may not be properly performed and a blocking phenomenon may occur. When the amount exceeds 10 parts by weight, There may arise a problem that an initiator is precipitated on the surface when left standing for a long time by the initiator.

The urethane acrylate oligomer may include 10 to 20 wt% of isocyanate, 10 to 40 wt% of polyol compound, and 50 to 80 wt% of acrylate monomer based on the total weight of the oligomer based on the solid content.

If the content of isocyanate is less than 10% by weight, the problem of chemical resistance may occur. If the content of isocyanate is more than 20% by weight, problems of polymer formation may occur.

When the content of the polyol compound is less than 10% by weight, the effect of improving the hardness, heat resistance and flexibility is low due to a low increase in the degree of crosslinking for improving the hardness. When the content exceeds 40% by weight, It may be difficult to process the film.

The hard coating composition of the present invention may further contain 60 to 140 parts by weight of inorganic particles per 100 parts by weight of the urethane acrylate oligomer based on the solid content. The inorganic particles are included for controlling the refractive index of the hard coating composition, and inorganic particles known in this field can be used without limitation.

As the aromatic polyol compound to be included in the polyol compound used in the present invention, a compound known in this field can be used, and typical examples thereof include bisphenol series such as bisphenol A, bisphenol F and methylene bis (4-hydroxyphenyl) Selected from the group consisting of resorcinol, dihydroxynaphthalene, dihydroxybiphenyl, dihydroxyphenylethanol, dihydroxypyridine, dihydroxyquinazoline, dihydroxytetrahydronaphthalene, dihydroxypyrimidine, etc. May be used.

The aliphatic polyol compound that may be used together with the aromatic polyol compound is not particularly limited and a compound known in the art may be used. For example, there can be mentioned 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl- Diol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonene diol, 1,10-decene diol, 1,4-cyclohexane Dimethanol, 1,3-cyclohexane dimethanol, 1,4-cyclohexane diol, 1,3-cyclohexane diol, tricyclohexane dimethanol, pentacyclopentadecane dimethanol, 1, Alkylene diols having 2 to 12 carbon atoms such as 4-butanediol, 1,6-hexanediol and 1,12-dodecane diol; There may be mentioned polyethers such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, and polydecamethylene glycol. Diol.

Among the acrylate monomers used in the present invention, the aromatic acrylate monomers include Compounds known in the art may be used, and at least one selected from the group consisting of bisphenol A-based acrylate, naphthalene-based acrylate, isobornyl acrylate, amanthyl-based acrylate and the like may be used .

Representative examples of the naphthalene-based acrylate include naphthalene-1,5-diacrylate, 1-naphthyl acrylate, and C1-C5 alkyl acrylates substituted with a naphthyl group.

The aliphatic acrylate monomers that can be used together with the aromatic acrylate monomers are not particularly limited, and compounds known in the art may be used. If the urethane acrylate oligomer does not contain an aliphatic acrylate monomer, the problem of hardness may cause a problem of insufficient hardness.

Examples of the aliphatic acrylate monomer include hydroxyethyl acrylate, hydroxypropyl methacrylate, methoxypolyethylene glycol acrylate, ethoxypolyethylene glycol acrylate, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl methacrylate Acrylate, and aliphatic modified acrylate, among which glycidyl methacrylate can be more preferably used.

As the isocyanate used in the present invention, those known in the art may be used, for example, 4,4'-diphenylmethane diisocyanate (MDI), 2,6- and 2 , 2,6-toluene diisocyante (TDI), tetramethyl-1,3-xylene diisocyanate (TMXDI), and the like.

The urethane acrylate oligomer according to the present invention preferably has a weight average molecular weight of 6,000 to 10,000 g / mol in consideration of the hardness of the hard coat film. If the weight average molecular weight is less than 6,000 g / mol, the hard coat layer is softened The hard coating function such as scratch resistance and film strength may be deteriorated. When the weight average molecular weight exceeds 10,000 g / mol, scratch resistance and the like are excellent, but hardening shrinkage becomes large, There is a problem such as deterioration of workability due to a considerably high problem and viscosity.

The urethane acrylate oligomer according to the present invention can be obtained by preparing a urethane prepolymer having an isocyanate end by using a reaction catalyst such as a polyhydric alcohol, dibutyl tin dilaurate and the like and an isocyanate and then reacting the urethane acrylate oligomer with an aliphatic acrylate monomer and an aromatic acrylate monomer And then reacting until the terminal isocyanate is completely consumed.

The photo-curable material included in the hard coating composition of the present invention is not particularly limited, and examples thereof include dipentaerythritol pentaacrylate, trihydroxy ethyl isocyanurate triacrylate, isocyanurate di (meth) acrylate, trimethyl (Meth) acrylate, propylene oxide modified trimethylol propane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, and caprolactone-modified dipentaerythritol hexa (meth) acrylate, tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (Meth) acrylate, and the like, and a polyfunctional acrylate selected from the group consisting of Can be used in the or in combination of two or more.

The photopolymerization initiator included in the hard coating composition of the present invention can be divided into a photopolymerizable prepolymer of the radical polymerization type or a photopolymerization initiator for the photopolymerizable monomer and a photopolymerization initiator for the cation polymerizable photopolymerizable prepolymer.

The photopolymerization initiator for the radical polymerizable type photopolymerizable prepolymer or the photopolymerizable monomer may be at least one selected from the group consisting of benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin- , Acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy- 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) Phenyl-2 (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methyl anthraquinone, 2-aminothraxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethyl Thio Wherein the photopolymerization initiator for the cationic polymerization type photopolymerizable prepolymer is a mixture of one or more selected from the group consisting of aromatic oxysulfonium Ion, aromatic iodonium ion and the like, and an anion such as tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, or the like. .

The refractive index of the hard coating composition of the present invention may be 1.35 to 1.70. Therefore, it can be more usefully used when the refractive index is 1.58 to 1.70, which is difficult to manufacture with conventional compositions.

When the hard coating composition of the present invention is used, there is an advantage that the required refractive index can be obtained even when the inorganic particles are not used or at least used.

The method for preparing the hard coating composition according to the present invention can be produced by mixing the urethane acrylate oligomer, the photo-curable material and the photopolymerization initiator into a solvent.

Examples of the solvent include alcohols such as methanol, ethanol, propanol and isopropanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as methyl acetate and ethyl acetate; aromatic compounds such as toluene, benzene and xylene; , And the solvent may be used in any amount as long as it can sufficiently dissolve the polyurethane-containing urethane acrylate oligomer, photo-curable material and photopolymerization initiator.

The present invention also relates to a hard coating film formed with a hard coating layer formed by applying the hard coating composition on one side or both sides of a substrate.

The hard coating film according to the present invention can be produced by applying the hard coating composition prepared as described above to one side or both sides of the substrate and irradiating ultraviolet rays. The hard coating composition may be applied to the substrate by any one of spraying, dip coating, spin coating, screen coating, inkjet printing, pad printing, knife coating, kiss coating, bar coating and gravure coating And the thickness of the hard coating layer formed of the hard coating composition can be easily controlled depending on the kind of the substrate, application, etc. However, it is preferably 2 to 10 占 퐉 in terms of securing the hardness and flexibility of the hard coating layer at the same time.

In addition, the substrate may be formed of inorganic materials such as glass, quartz, glass wafers, silicon wafers and the like, polyethylene sulfonate (PES) film, polyethylene terephthalate (PET) film, polycarbonate (PC) and polymethylmethacrylate , Surlyn (manufactured by BFGoodrich of the United States), and the like can be coated on various transparent substrates such as organic synthetic resin films.

In particular, the hard coating composition according to one embodiment of the present invention can be used to coat plastic liquid crystal display material surfaces and flat panel display liquid crystal screen surfaces, computer monitor screens and safety screen surfaces, other glass, polycarbonate and acrylic plates, polyethylene phthalate or polyethylene sulphonate films And the like.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are intended to further illustrate the present invention, and the scope of the present invention is not limited by the following examples. The following examples can be suitably modified or changed by those skilled in the art within the scope of the present invention.

Manufacturing example  1 to 4 and comparison Manufacturing example  1 to 3: urethane Acrylate Oligomer  synthesis

Urethane acrylate oligomer was synthesized according to the following method according to the components and contents in Table 1 below.

The polyol compound and the reaction catalyst were put into a 5,000-μl four-necked flask equipped with an oil bath, a thermometer, a reflux condenser and a dropping funnel, and the mixture was stirred at 70 ° C for 30 minutes. The isocyanate compound was added in three steps Then, the reaction was carried out for 3 hours to prepare a urethane prepolymer having an isocyanate terminal. At this time, the value of R (N = C = O / OH, ratio of isocyanate group to hydroxyl group) of the urethane prepolymer having isocyanate terminal was 1.91.

Thereafter, the temperature of the reactor was dropped to 50 캜 to prevent thermal polymerization of the vinyl group, and then the acrylate compound was added thereto, and the mixture was stirred for 5 hours until the isocyanate group was completely consumed. Using the FT-IR spectrum, it was confirmed that the residual isocyanate was not present at the characteristic peak of N = C = O in the vicinity of 2270 cm ^-1 , and the reaction was terminated to prepare a urethane acrylate oligomer.

Isocyanate Polyol compound Acrylate monomer catalyst ingredient content
(g) ingredient content
(g) ingredient content
(g) ingredient content
(g) Production Example 1 TMXDI 225 1,5-dihydroxynaphthalene 525 Bisphenol A ethoxylate diacrylate 760 Dibutyl tin dilaurate 0.03 Production Example 2 TMXDI 225 1,5-dihydroxynaphthalene 263 Bisphenol A ethoxylate diacrylate 380 Dibutyl tin dilaurate 0.03 Pentaerythritol 263 Hydroxyethyl acrylate 380 Production Example 3 MDI 225 Resorcinol 263 1-naphthyl
Acrylate 380 Dibutyl tin dilaurate 0.03 Pentaerythritol 263 Hydroxyethyl acrylate 380 Production Example 4 MDI 225 1,5-dihydroxynaphthalene 263 1-naphthyl
Acrylate 380 Dibutyl tin dilaurate 0.03 Pentaerythritol 263 380 Comparative Preparation Example 1
Hexamethylene diisocyanate 225 The carbonate diol (PCDL) 263 Hydroxyethyl acrylate 380 Dibutyl tin dilaurate 0.03 Pentaerythritol 263 Comparative Production Example 2
TMXDI 225 1,5-dihydroxynaphthalene 263 Glycidyl methacrylate 380 Dibutyl tin dilaurate 0.03 Pentaerythritol 263 Comparative Production Example 3
TMXDI 225 The carbonate diol (PCDL) 263 Bisphenol A ethoxylate diacrylate 380 Dibutyl tin dilaurate 0.03 Pentaerythritol 263 Hydroxyethyl acrylate 380

week)

TMXDI: Tetramethyl-1,3-xylene diisocyanate

MDI: Methylene Diphenyl Diisocyanate

Example  1 to 4: Hard coating  Composition manufacturing

33.3 parts by weight of dipentaerythritol pentaacrylate (Donga Synthesis, M-402), 30.3 parts by weight of trihydroxyethyl isocyanurate triacrylate (manufactured by Eastman Chemical Co., Ltd.), and 100 parts by weight of the urethane acrylate oligomer synthesized in Production Examples 1 to 4 , M-315) 16.6 parts by weight of, as a photopolymerization initiator 1-hydroxycyclohexyl phenyl ketone, 5 parts by weight of inorganic particles, 100 parts by weight of ZrO _2, and a hard mixed for one hour 234 parts by weight of methyl ethyl ketone as a solvent at 60 ℃ Coating composition.

Comparative Example  1 to 3: Hard coating  Composition manufacturing

A hard coat composition was prepared in the same manner as in Example 1 except that the urethane acrylate oligomer synthesized in Comparative Production Examples 1 to 3 was used.

Example  1-1 to 4-1: Hard coating  Film manufacturing

The hard coating compositions prepared in Examples 1 to 4 were coated on one surface of polyethylene terephthalate (KOLON, thickness: 50 탆) as a substrate, dried in an oven at 80 캜 for 3 minutes, and irradiated with ultraviolet rays (Fusion, 600 mJ / Cm < 2 >) and irradiated with 500 mJ / cm < 2 > in the direction in which the hard coating composition was applied to prepare a hard coating film (thickness: 53 m).

Comparative Example  1-1 to 3-1: Hard coating  Composition manufacturing

Hard coating films were prepared in the same manner as in Example 1-1 except that the hard coating compositions prepared in Comparative Examples 1 to 3 were used.

Test Example : Hard coating  Evaluation of physical properties of film

(1) Pencil Hardness

The hard coating films prepared in the Examples and Comparative Examples were measured for hardness by using a pencil hardness tester of IMOTO, Japan, and the results are shown in Table 2 below.

 [Measuring conditions]

a. Speed of 30mm / min

b. The loads are 500gf and 750gf

c. Japan's IMOTO pencil hardness tester

 (2) Scratch resistance

When the hard coating films prepared in Examples and Comparative Examples were subjected to minimal pressure using the basis weight of a Big Heart test apparatus manufactured by IMOTO, Japan, scratches of the hard coating films were measured. The degree of damage due to the occurrence of scratches was judged by naked eyes, and the results are shown in Table 2 below.

<Evaluation Criteria>

Poor scratch resistance ← X <Δ <○ <◎ → excellent scratch resistance

 (3) Adhesion ( Cross Cut )

Using the knife on the coating film of the hard coating film prepared in the above Examples and Comparative Examples, 11 straight lines were drawn at intervals of 1 mm to form 100 squares, followed by peeling test using a tape (3M Scotch Magic Tape) And the results are shown in Table 2 below.

<Evaluation Criteria>

Adhesion poor ← X <Δ <○ <◎ → Good adhesion

 (4) Flexibility

The hard coating film prepared in the above Examples and Comparative Examples was wound around a 20-mm rod to observe cracks on the surface. The results are shown in Table 2 below.

<Evaluation Criteria>

Flexibility poor ← X <△ <○ <◎ → Flexibility

(5) Chemical resistance

The hard coat films prepared in the Examples and Comparative Examples were measured for their chemical resistance (ΔR = reflectance before dipping - reflectivity after dipping) by measuring the reflectance before and after dipping in a 5% NaON solution at 40 ° C. for 30 minutes, The results are shown in Table 2 below.

(6) Refractive index  Measure

The refractive indexes of the hard coating films prepared in Examples and Comparative Examples were measured using an Abbe refractometer and the results are shown in Table 2 below.

division Pencil hardness
(Load: 500 gf) Scratch resistance Adhesiveness Flexibility Chemical resistance Refractive index Example 1-1 H ○ ◎ ○ 0.4 1.570 Example 2-1 H ○ ◎ ◎ 0.8 1.580 Example 3-1 H ○ ○ △ 0.4 1.590 Example 4-1 H ○ ◎ ○ 0.3 1.610 Comparative Example 1-1 H △ ○ ○ 0.8 1.520 Comparative Example 2-1 H ○ ○ ○ 0.8 1.520 Example 3-1 H △ ◎ ○ 0.4 1.520

As shown in Table 1, the hard coating films prepared in the Examples were superior in hardness, scratch resistance, adhesion, and flexibility as compared with the hard coating films prepared in Comparative Examples. In particular, it was confirmed that the chemical resistance and the refractive index were very excellent. Therefore, the hard coating film prepared using the hard coating composition according to the present invention can be applied as a display protective film requiring excellent physical properties and high refractive index.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (8)

A urethane acrylate oligomer, a photocurable material and a photopolymerization initiator,
The urethane acrylate oligomer comprises an isocyanate, a polyol compound and an acrylate monomer,
Wherein the polyol compound comprises an aromatic polyol compound in an amount of 30 to 100 wt% based on the total weight of the polyol compound based on the solid content, and the acrylate monomer has an aromatic acrylate monomer in an amount of 30 to 100 wt% based on the total weight of the acrylate monomer, By weight based on the total weight of the composition. The method according to claim 1,
20 to 60 parts by weight of a photocurable material and 3 to 10 parts by weight of a photopolymerization initiator based on 100 parts by weight of a urethane acrylate oligomer on the basis of a solid content;
Wherein said urethane acrylate oligomer comprises from 10 to 20% by weight of isocyanate, from 10 to 40% by weight of polyol compound and from 50 to 80% by weight of acrylate monomer based on the total weight of oligomer based on solids content. The method of claim 2,
Further comprising 60 to 140 parts by weight of inorganic particles based on 100 parts by weight of the urethane acrylate oligomer based on the solid content. The method according to claim 1,
Wherein the polyol compound comprises an aromatic polyol compound in an amount of 35 to 45% by weight based on the solid content of the polyol compound, and the acrylate monomer has an aromatic acrylate monomer in an amount of 60 to 60% by weight based on the solid content, &Lt; / RTI &gt; by weight of the composition. The method according to claim 1,
Wherein the aromatic polyol compound is selected from the group consisting of bisphenol A, bisphenol F, methylene bis (4-hydroxyphenyl), resorcinol, dihydroxynaphthalene, dihydroxybiphenyl, dihydroxyphenylethanol, dihydroxypyridine, dihydroxy At least one selected from the group consisting of quinoxaline, dihydroxytetrahydronaphthalene, and dihydroxypyrimidine;
Wherein the aromatic acrylate monomer is at least one selected from the group consisting of bisphenol A acrylate, naphthalene acrylate, isobornyl acrylate, and amanthyl acrylate. The method according to claim 1,
Wherein the urethane acrylate oligomer has a weight average molecular weight of from 6,000 to 10,000 g / mol. The method according to claim 1,
Wherein the hard coating composition has a refractive index of 1.35 to 1.70. A hard coating film formed by applying a hard coating composition according to any one of claims 1 to 7 on one side or both sides of a substrate to form a hard coating layer.