KR20170103647A - Hard coating composition - Google Patents

Abstract

An objective of the present invention is to provide a hard coating composition which exhibits excellent impact resistance and flexure resistance. The hard coating composition according to the present invention for achieving the objective comprises a high elongation oligomer having an elastic modulus of 10 to 3000 MPa and a rupture elongation of 30 to 150%. The hard coating composition according to the present invention has an effect of improving impact resistance and flexure resistance by comprising a high elongation oligomer having specific ranges of the elastic modulus and the rupture elongation.

Description

[0001] HARD COATING COMPOSITION [0002]

The present invention relates to a hard coating composition having excellent impact resistance and bending resistance.

With the recent development of mobile devices such as smart phones and tablet PCs, thinner and slimmer display substrates have been required. Glass or tempered glass is generally used as a material having excellent mechanical properties on a display window or a front plate of such a mobile device. However, the glass causes the weight of the mobile device to be heavy due to its own weight, and has a problem of breakage due to an external impact.

Plastic resins are being studied as a substitute for glass. The plastic resin composition is suitable for the trend of seeking a lighter mobile device because it is less likely to break even though it is lightweight. In particular, a composition for coating a hard coating layer on a supporting substrate to achieve a composition having properties of hardness and abrasion resistance has been proposed.

A method of increasing the thickness of the hard coat layer by a method of improving the surface hardness of the hard coat layer can be considered. In order to secure enough surface hardness to replace glass, it is necessary to implement a certain hard coating layer thickness.

However, as the thickness of the hard coat layer is increased, the surface hardness can be increased. However, since the hard coat layer is hardened and shrunk, wrinkles and curls are increased and the hard coat layer is easily cracked or peeled. Is not easy.

Recently, several methods have been proposed for realizing the hardening of the hard coating film and solving the problem of curling due to cracking or hardening shrinkage of the hard coating layer.

Korean Patent Laid-Open Publication No. 2014-0027022 discloses a hard coat composition having improved impact resistance including an acrylate monomer and a photo-curable elastomer having a certain range of elongation. However, the hard coating compositions disclosed above are not sufficient for flex resistance and impact resistance to replace the glass panel of the display.

Korean Patent Laid-Open Publication No. 2011-0078783 discloses a hard coating composition having improved surface hardness and impact resistance by containing 5 to 80 wt% of an alkylene glycol-based acrylic monomer. However, the hard coating compositions disclosed above are also not sufficient for impact resistance to replace the glass panel of the display.

Korean Patent Publication No. 2014-0027022 (April 31, 2014, LG Chemical Co., Ltd.) Korea Open Patent No. 2011-0078783 (2011.07.07, Cheil Industries Co., Ltd.)

It is an object of the present invention to provide a hard coating composition exhibiting excellent impact resistance and bending resistance.

In order to accomplish the above object, the hard coating composition according to the present invention is characterized by comprising a high-stretch oligomer having a modulus of elasticity of 10 to 3000 MPa and a elongation at break of 30 to 150%.

The hard coating composition according to the present invention has the effect of improving impact resistance and flex resistance by including a highly stretched oligomer having a specific range of elastic modulus and elongation at break.

Whenever a part is referred to as "including " an element in the present invention, it is to be understood that it may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Hereinafter, preferred embodiments of the present invention will be described in detail.

< Hard coating  Composition>

The hard coating composition according to one embodiment of the present invention comprises a high-stretch oligomer having a modulus of elasticity of 10 to 3000 MPa and a elongation at break of 30 to 150%. When the modulus of elasticity and elongation at break of the hard coating composition satisfy the above ranges, excellent flexing resistance and impact resistance are exhibited.

High elongation  Oligomer

The hard coating composition according to the present invention comprises a high stretch oligomer.

The high-stretch oligomer comprises a photocurable (meth) acrylate oligomer.

The photocurable (meth) acrylate oligomer may include at least one selected from the group consisting of epoxy (meth) acrylate, urethane (meth) acrylate and polyester (meth) acrylate.

The epoxy (meth) acrylate can be obtained by reacting an epoxy compound with a carboxylic acid having a (meth) acryloyl group. Specific examples of the epoxy compound include glycidyl (meth) acrylate, a hindered glycidyl ether of a straight chain alcohol having 1 to 12 carbon atoms, diethylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, Bisphenol A diglycidyl ether, ethylene oxide-modified bisphenol A diglycidyl ether, propylene oxide-modified bisphenol A diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, hydrogenated bisphenol A Diglycidyl ether, glycerin diglycidyl ether, and the like. Examples of the carboxylic acid having a (meth) acryloyl group include (meth) acrylic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxyethylhexahydrophthalic acid and the like.

The urethane (meth) acrylate can be produced in the presence of a catalyst having a polyfunctional (meth) acrylate having a hydroxyl group in the molecule and an isocyanate group.

Examples of the (meth) acrylate having a hydroxyl group in the molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate mixture, and a mixture of dipentaerythritol penta / hexa (meth) acrylate can be used.

Examples of the compound having an isocyanate group in the molecule include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, Diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis (isocyanatomethyl) cyclohexane, trans-1,4-cyclohexane diisocyanate, Methylenebis (cyclohexylisocyanate), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethyl xylene- Diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis (2,6-dimethylphenyl isocyanate), 4,4'-oxybis (phenylisocyanate), hexamethylene diisocyanate Trifunctional isocyanate, and trimethane propanol adduct. Toluene diisocyanate May be used.

Specific examples of the polyester (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di Propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di Diacrylate such as 1,6-hexanediol di (meth) acrylate, tricyclodecanediol (meth) acrylate and bisphenol A di (meth) acrylate, trimethylolpropane tri (meth) (Meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol Other (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris (2- (meth) acryloyl oxyethyl) isocyanurate.

It is preferable to use a mixture of urethane (meth) acrylate and polyester (meth) acrylate, or to have both a polyester and a urethane group in one molecule.

In particular, by using an acrylate oligomer having a linear structure, it is possible to form a hard coat film having an elongation of 30% or more, preferably a polyester (meth) acrylate having a linear structure and having excellent flexibility It is more preferable to use it.

The high-stretch oligomer may be contained in an amount of 1 to 90% by weight, preferably 5 to 80% by weight based on 100% by weight of the entire hard coating composition. When the content of the high-stretch oligomer is less than 1% by weight, it is difficult to form a hard coat composition having a sufficient level of impact resistance even if the formation of the coat is difficult or even if it is formed. When the content of the hard coat composition exceeds 90% There may arise a problem that the uniformity of the coating film is lowered due to the high viscosity during the production of the film.

An embodiment of the present invention may further comprise at least one of the hard coating composition selected from the group consisting of a solvent, a photoinitiator and an additive.

solvent

The above-mentioned solvent can dissolve or disperse the above-mentioned composition and can be used without limitation as long as it is known as a solvent for the hard coating composition in the technical field.

Specific examples of the solvent include alcohols (methanol, ethanol, isopropanol, butanol, methylcellulose, ethylcellulose etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, Cyclohexanone and the like), an acetate type (ethyl acetate, propyl acetate, n-butyl acetate, tertiary butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, Benzene or derivatives thereof (benzene, toluene, xylene, etc.), ethers (such as diethylene glycol, propylene glycol monopropyl ether acetate, methoxybutyl acetate and methoxypentyl acetate) Glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether , A propylene glycol monomethyl ether and the like) can be preferably used. These solvents may be used alone or in combination of two or more.

The solvent can be easily removed from the substrate after curing of the hard coating composition by using a solvent having a low solubility for the substrate to which the hard coating composition of the present invention is applied.

The solvent may include 10 to 95% by weight based on 100% by weight of the total hard coat composition. When the content of the solvent is less than 10% by weight, the viscosity increases and the workability is poor. When the content of the solvent is more than 95% by weight, a long time is required in the drying process and the economical efficiency is low.

Photoinitiator

The photoinitiator may be any one as long as it is used in the technical field, and may be at least one selected from the group consisting of hydroxy ketones, aminoketones, and hydrogen recycling photoinitiators.

Specifically, 2-methyl-1- [4- (methylthio) phenyl] 2-morpholinopropanone-1, diphenyl ketone, benzyldimethyl ketal, 2-hydroxy- , 4-hydroxycyclophenyl ketone, 2,2-dimethoxy-2-phenyl-acetophenone, anthraquinone, fluorene, triphenylamine, carbazole, 3-methylacetophenone, 4-dimethoxybenzophenone, 1-hydroxycyclohexyl phenyl ketone, benzophenone, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, etc., Or a combination of two or more.

The photoinitiator may be included in an amount of 0.1 to 10% by weight, preferably 1 to 5% by weight based on 100% by weight of the total hard coat composition. If the content of the photoinitiator is less than 0.1% by weight, the curing speed of the hard coating composition is slowed down and uncured and mechanical properties are deteriorated. If the content of the photoinitiator exceeds 10% by weight, cracks may occur in the coating due to overcuring.

additive

The additive may include at least one selected from the group consisting of inorganic nanoparticles, leveling agents, and stabilizers.

(1) Inorganic nanoparticles

The inorganic nanoparticles may be optionally added to improve the hardness of the hard coating film. Specifically, when the inorganic nanoparticles are included in the hard coating composition, there is an advantage that the mechanical properties can be further improved. More specifically, the inorganic nanoparticles are uniformly formed in the coating film, and the mechanical properties such as abrasion resistance, scratch resistance and pencil hardness can be improved.

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

The inorganic nanoparticles are _{Al 2 O 3, SiO 2,} ZnO, ZrO 2, BaTiO 3, TiO 2, Ta 2 O 5, Ti 3 O 5, ITO, IZO, ATO, ZnO-Al, Nb 2 O 3, SnO , MgO, and combinations thereof. The metal oxide may include, but is not limited to, metal oxides commonly used in the art.

Specifically, the inorganic nanoparticles may be Al ₂ O ₃ , SiO ₂ , or ZrO ₂ . The inorganic nanoparticles may be prepared directly or commercially available ones. In the case of commercially available products, the inorganic nanoparticles may be dispersed in an organic solvent at a concentration of 10 to 80% by weight.

(2) Leveling agent

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

Specifically, the leveling agent may be selected from the group consisting of BYK-323, BYK-331, BYK-333, BYK-337, BYK-375, BYK-377, BYK-378, TEGO Glide 410, TEGO Glide 411, TEGO Glide 415, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 455, TEGO Rad 2100, TEGO Rad 2200N, TEGO Rad 2250, TEGO Rad 2300, , FC-4430 and FC-4432 manufactured by 3M Company. However, the present invention is not limited thereto, and leveling agents conventionally used in the art can be applied.

(3) Stabilizer

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

In the present invention, the ultraviolet stabilizer means an additive added for the purpose of blocking or absorbing ultraviolet rays to protect the adhesive since the surface of the cured coating film is decomposed by continuous ultraviolet ray exposure to be discolored and crumbled.

The ultraviolet stabilizer may be classified into an absorbent, a quencher, and a hindered amine light stabilizer (HALS) according to the action mechanism. Also, depending on the chemical structure, it is possible to use Phenyl Salicylates (absorbent), Benzophenone (absorbent), Benzotriazole (absorber), Nickel derivative (quencher), Radical Scavenger .

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

The heat stabilizer is a commercially applicable product, and can be used either singly or as a mixture of a polyphenol as a primary heat stabilizer, a phosphite as a secondary heat stabilizer, and a lactone system. The ultraviolet stabilizer and the heat stabilizer can be appropriately used at a level at which the ultraviolet curing property is not affected.

< Hard coating  Film>

Another embodiment of the present invention is also capable of forming a hard coating film by forming a cured product of the hard coating composition on a transparent substrate.

In this case, the thickness of the cured product of the hard coating composition is 50 to 300 mu m. When the thickness of the cured product of the hard coating composition is less than 50 탆, the impact resistance may be lowered, and when the thickness exceeds 300 탆, the flexing resistance may be lowered.

materials

The hard coating composition according to the present invention can be applied to one surface of a substrate, then cured, and then peeled and transferred to another desired substrate.

In addition, the hard coating composition according to the present invention can be applied on one side of a substrate, then cured, and then peeled and used on another desired substrate using a pressure-sensitive adhesive or an adhesive.

In the present invention, the substrate to which the hard coating composition is applied may be any substrate as used in the art. For example, a transparent substrate may be used.

The transparent substrate may be any polymer film having transparency.

Specific examples thereof include cycloolefin-based derivatives having units of monomers including cycloolefins such as norbornene or polycyclic norbornene monomers, cellulose (including diacetylcellulose, triacetylcellulose, acetylcellulose butyrate, isobutylester cellulose, Polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinyl pyrrolidone, Polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene Naftal A film formed of a polymer such as acrylate, polycarbonate, polyurethane, or epoxy, and an unstretched uniaxial or biaxially oriented film may be used. These polymers may be used alone or in combination of two or more.

Among the above-mentioned transparent materials, preferred are monoaxially or biaxially oriented polyester films excellent in transparency and heat resistance, cycloolefin derivative films excellent in transparency and heat resistance, capable of coping with the enlargement of the film, polymethyl methacrylate films, Triacetylcellulose and isobutylester cellulose films having no transparency and optically anisotropy can be used.

The hard coating composition according to the present invention can be used in the form of a base material hard coat layer obtained by applying the composition on one side of the base material and removing the base material after curing and the inorganic material hard coating layer can be used as a rigid or flexible display Can be used. Specifically, it can be used as a substitute for a cover glass of a display such as LCD, OLED, LED, FED, various mobile communication terminals, a touch panel of a smart phone or a tablet PC, a total paper, or the like.

The present invention provides an image display device provided with the inorganic material hard coat layer.

Further, the present invention provides a window of a flexible display device having the inorganic material hard coat layer.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims. In the following Examples and Comparative Examples, "%" and "part" representing the contents are by weight unless otherwise specified.

Manufacturing example  1 to 7: Hard coating  Preparation of composition

Manufacturing example  One

70 parts by weight of urethane acrylate (product of Shin Nakamura, UA-122P), 25 parts by weight of methyl ethyl ketone, 4.5 parts by weight of a photoinitiator (1-hydroxy-cyclohexyl-phenyl-ketone, ) And 0.5 part by weight of a leveling agent (BYK-MEMS, BYK-3570) were mixed using a stirrer and filtered using a filter made of polypropylene (PP) to prepare a hard coating composition. At this time, the modulus of elasticity of the urethane acrylate was 2070 MPa and the elongation at break was 58%.

Manufacturing example  2

 70 parts by weight of urethane acrylate (Shin Nakamura, UA-232P), 25 parts by weight of methyl ethyl ketone, 4.5 parts by weight of a photoinitiator (1-hydroxy-cyclohexyl-phenyl-ketone, ) And 0.5 part by weight of a leveling agent (BYK-MEMA, BYK-3570) were mixed using a stirrer and filtered using a filter made of polypropylene (PP) to prepare a hardcoat composition. At this time, the modulus of elasticity of the urethane acrylate was 1320 MPa and the elongation at break was 135%.

Manufacturing example  3

70 parts by weight of urethane acrylate (product of Shin Nakamura, UA-122P), 25 parts by weight of methyl ethyl ketone, 4.5 parts by weight of a photoinitiator (1-hydroxy-cyclohexyl-phenyl-ketone, ) And 0.5 part by weight of a leveling agent (BYK-MEMS, BYK-3570) were mixed using a stirrer and filtered using a filter made of polypropylene (PP) to prepare a hard coating composition. At this time, the modulus of elasticity of the urethane acrylate was 2570 MPa and the elongation at break was 67%.

Manufacturing example  4

20 parts by weight of pentaerythritol triacrylate, 25 parts by weight of methyl ethyl ketone, 4.5 parts by weight of a photoinitiator (1-hydroxy-cyclohexyl-phenyl-ketone, 1-hydroxy-cyclohexyl-phenyl-ketone) and 0.5 parts by weight of a leveling agent (BYK-MEMS, BYK-3570) were mixed using a stirrer and filtered using a polypropylene (PP) Respectively. At this time, the modulus of elasticity of the mixture of urethane acrylate and pentaerythritol triacrylate was 3220 MPa and the elongation at break was 12%.

Manufacturing example  5

35 parts by weight of urethane acrylate (product of Shin Nakamura, UA-122P), 35 parts by weight of pentaerythritol triacrylate, 25 parts by weight of methyl ethyl ketone, 4.5 parts by weight of photoinitiator (1 -hydroxy-cyclohexyl- 1-hydroxy-cyclohexyl-phenyl-ketone) and 0.5 parts by weight of a leveling agent (BYK-MEMS, BYK-3570) were mixed using a stirrer and filtered using a polypropylene (PP) Respectively. At this time, the modulus of elasticity of the mixture of acrylate and pentaerythritol triacrylate was 3705 MPa and the elongation at break was 7%.

Manufacturing example  6

20 parts by weight of urethane acrylate (product of Shin Nakamura, UA-122P), 50 parts by weight of pentaerythritol triacrylate, 25 parts by weight of methyl ethyl ketone, 4.5 parts by weight of a photoinitiator (1 -hydroxy-cyclohexyl- 1-hydroxy-cyclohexyl-phenyl-ketone) and 0.5 parts by weight of a leveling agent (BYK-MEMS, BYK-3570) were mixed using a stirrer and filtered using a polypropylene (PP) Respectively. At this time, the modulus of elasticity of the mixture of acrylate and pentaerythritol triacrylate was 4210 MPa and elongation at break was 5%.

Manufacturing example  7

35 parts by weight of urethane acrylate (product of Shin Nakamura, UA-122P), 35 parts by weight of dipentaerythritol hexaacrylate, 25 parts by weight of methyl ethyl ketone, 4.5 parts by weight of a photoinitiator (1 -hydroxy-cyclohexyl- , 1-hydroxy-cyclohexyl-phenyl-ketone) and 0.5 parts by weight of a leveling agent (BYK-MEMS, BYK-3570) were mixed using a stirrer and filtered using a polypropylene (PP) . At this time, the modulus of elasticity of the mixture of acrylate and dipentaerythritol hexaacrylate was 4570 MPa and elongation at break was 3%.

Example  1 to 5 and Comparative Example  1 to 6: The hard coat layer  Produce

Example  One

The hard coating composition prepared in Preparation Example 1 was cured on a polyester (PET) base film having a thickness of 50 탆 and then coated to a thickness of 200 탆. After coating, the solvent was dried and irradiated with UV light intensity of 500 mJ / cm ² to cure the composition to produce a hard coating film, and then a polyester (PET) base film was peeled off to produce an impact resistant hard coating layer of an inorganic material.

Example  2

The procedure of Example 1 was repeated except that the hard coating composition prepared in Preparation Example 2 was used.

Example  3

The procedure of Example 1 was repeated except that the hard coating composition prepared in Preparation Example 3 was used.

Example  4

The procedure of Example 1 was repeated except that the hard coat layer after curing had a thickness of 70 탆.

Example  5

The procedure of Example 1 was repeated, except that the thickness of the hard coat layer after curing was 250 占 퐉.

Comparative Example  One

The procedure of Example 1 was repeated except that the hard coating composition prepared in Preparation Example 4 was used.

Comparative Example  2

The procedure of Example 1 was repeated except that the hard coating composition prepared in Preparation Example 5 was used.

Comparative Example  3

The procedure of Example 1 was repeated except that the hard coating composition prepared in Preparation Example 6 was used.

Comparative Example  4

The procedure of Example 1 was repeated except that the hard coating composition prepared in Preparation Example 7 was used.

Comparative Example  5

The procedure of Example 1 was repeated except that the hard coat layer after curing had a thickness of 10 mu m.

Comparative Example  6

The procedure of Example 1 was repeated except that the hard coat layer after curing had a thickness of 350 占 퐉.

Experimental Example

The physical properties of the hard coat layer prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were measured by the following methods, and the results are shown in Table 1. The measuring method and evaluation method used in the present invention are as follows.

(1) Flexibility

The hard coat layer prepared in Examples and Comparative Examples was folded in half so that the gap between the faces was 6 mm, and then cracks were observed in the folded portion when the hard coat layer was spread again. The results are shown in Table 1 below.

Good: cracking of folded parts

Poor: cracks in the fold

(2) Impact resistance

The hard coat layer prepared in Examples and Comparative Examples was bonded to a glass with 50 탆 OCA (elastic modulus 0.08 MPa), and then peeled off at a height of 50 cm from the surface of the hard coat layer to determine the weight of the peak metal Were measured. The results are shown in Table 1 below.

Flexibility Impact resistance Example 1 Good 35g Example 2 Good 50g Example 3 Good 40g Example 4 Good 35g Example 5 Good ≥65g Comparative Example 1 Good 15g Comparative Example 2 Bad 10g Comparative Example 3 Bad 5g Comparative Example 4 Bad 5g Comparative Example 5 - - Comparative Example 6 Bad ≥65g

With reference to Table 1, Examples 1 to 5 having the modulus of elasticity and elongation at break of the present invention were superior in flex resistance and impact resistance to those of Comparative Examples 1 to 4, which were out of the range of the modulus of elasticity and elongation at break .

Further, when the thickness of the cured product of the hard coating composition satisfies the preferable thickness range (50 to 300 탆) in the present invention (Examples 1 to 5), when the thickness of the cured product of the hard coating composition exceeds the above- (Comparative Example 6), the thickness of the hard coating composition was less than the thickness range (Comparative Example 5), the thickness of the hard coating composition was insufficient, and the hard coating composition Could not be peeled off.

Claims (10)

A high-stretch oligomer having a modulus of elasticity of 10 to 3000 MPa and a elongation at break of 30 to 150%. The method according to claim 1,
Wherein the hard coating composition further comprises at least one of a solvent, a photoinitiator and an additive. The method according to claim 1,
Wherein the high-stretch oligomer comprises a photocurable (meth) acrylate oligomer. The method of claim 3,
(Meth) acrylate oligomer is selected from the group consisting of an epoxy (meth) acrylate, a urethane (meth) acrylate, a polyester (meth) acrylate and a By weight of the hard coat composition. The method according to claim 1,
Wherein the high-stretch oligomer is contained in an amount of 1 to 90% by weight based on 100% by weight of the entire hard coating composition. A hardcoat film comprising a cured product of the hard coating composition of any one of claims 1 to 5. The method according to claim 6,
Wherein the thickness of the cured product of the hard coating composition is 50 to 300 占 퐉. A window comprising a hardcoat film according to claim 6. An image display device comprising a window according to claim 8. 10. The method of claim 9,
Wherein the image display device is a flexible image display device.