WO2021246716A1 - Composition for forming easy-adhesion layer, and hard coating film using same - Google Patents

Abstract

The present invention provides a composition for forming an easy-adhesion layer, a hard coating film formed by using same, and an image display device provided with the hard coating film, the composition for forming an easy-adhesion layer comprising: a polysiloxane compound having a hydroxyl group on a side chain thereof; a light-transmissive resin; a photoinitiator; and a solvent. The composition for forming an easy-adhesion layer, according to the present invention, comprises the polysiloxane compound having the hydroxyl group on the side chain thereof, and the light-transmissive resin, and thus enables the enhancement of tight adhesion between a cycloolefin polymer substrate and a hard coating layer, thereby enabling the improvement of the bending resistance of the hard coating film.

Description

Composition for forming easily adhesive layer and hard coating film using same

The present invention relates to a composition for forming an easily adhesive layer and a hard coating film using the same, and more particularly, it is possible to improve the adhesion between the cycloolefin polymer substrate and the hard coating layer, and thus the flex resistance of the hard coating film can be improved. It relates to a composition for forming an easily adhesive layer, a hard coating film formed using the same, and an image display device provided with the hard coating film.

The hard coating film is used for the purpose of surface protection in image display devices such as liquid crystal displays, electroluminescence (EL) displays, plasma displays (PD), and field emission displays (FEDs).

Recently, a flexible display device that can maintain display performance even when bent like paper by using a flexible material such as plastic instead of the existing inflexible glass substrate is rapidly emerging as a next-generation display device, and hardness is increasing. Research is being conducted on hard coating films that are not only high in scratch resistance, but also do not have curls at the edges of the film during the manufacturing process or use, and have adequate flexibility to prevent cracks.

On the other hand, cycloolefin polymer (COP) has excellent transparency, heat resistance, dimensional stability, low hygroscopicity, low birefringence and optical isotropy, so it is expected to be used as a base material for a hard coating film. However, unlike an acrylic film or a polyester film, the cycloolefin polymer film has a small number of polar groups on the surface of the film, so the adhesion between the base film and the hard coating layer is poor.

Accordingly, Korean Patent Application Laid-Open No. 10-2017-0107995 discloses a hard coating film manufactured by interposing an easy-to-adhesive layer containing a mixture of a polyolefin-based resin and a styrene-acrylic resin.

However, the hard coating film has a problem in that it is difficult to exhibit sufficient adhesion between the cycloolefin polymer substrate and the hard coating layer because the easy-to-adhesive layer contains a resin component and the degree of crosslinking is low, and when applied to the hard coating film, the bending resistance is poor.

One object of the present invention is to provide a composition for forming an easily adhesive layer capable of improving the adhesion between the cycloolefin polymer substrate and the hard coating layer.

Another object of the present invention is to provide a hard coating film having improved bending resistance by being formed using the composition for forming an easily adhesive layer.

Another object of the present invention is to provide an image display device provided with the hard coating film.

On the other hand, the present invention provides a composition for forming an easily adhesive layer comprising a polysiloxane compound having a hydroxyl group in a side chain, a light-transmitting resin, a photoinitiator, and a solvent.

In one embodiment of the present invention, the polysiloxane compound having a hydroxyl group in the side chain may be included in an amount of 10 to 90% by weight based on 100% by weight of the total solid content in the composition for forming an easily adhesive layer.

In one embodiment of the present invention, the light-transmitting resin may include at least one selected from the group consisting of photocurable (meth)acrylate oligomers and monomers.

The composition for forming an easily adhesive layer according to an embodiment of the present invention may be used between the cycloolefin polymer substrate and the hard coating layer.

On the other hand, the present invention

a cycloolefin polymer substrate;

An easily adhesive layer formed on at least one surface of the cycloolefin polymer substrate, and

As a hard coating film comprising a hard coating layer formed on the easily adhesive layer,

It provides a hard coating film that the easily adhesive layer is formed using the composition for forming the easily adhesive layer.

The hard coating film according to an embodiment of the present invention has a total light transmittance of 90% or more, and the hard coating film is folded 200,000 times with a radius of curvature of 1 mm so that the hard coating layer is folded inside. Peeling of the coating layer may not occur.

In one embodiment of the present invention, the cycloolefin polymer substrate may be hydrophilized.

In one embodiment of the present invention, the hard coating layer may be formed using a hard coating composition comprising a light-transmitting resin, a photoinitiator and a solvent.

In one embodiment of the present invention, the light-transmitting resin may include at least one selected from the group consisting of photocurable (meth)acrylate oligomers and monomers.

On the other hand, the present invention provides an image display device provided with the hard coating film.

On the other hand, the present invention provides a window of a flexible display device provided with the hard coating film.

On the other hand, the present invention provides a polarizing plate provided with the hard coating film.

On the other hand, the present invention provides a touch sensor provided with the hard coating film.

The composition for forming an easily adhesive layer according to the present invention may include a polysiloxane compound having a hydroxyl group in a side chain and a light-transmitting resin to improve the adhesion between the cycloolefin polymer substrate and the hard coating layer, and thus the flex resistance of the hard coating film can be improved. have.

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

One embodiment of the present invention relates to a composition for forming an easily adhesive layer comprising a polysiloxane compound having a hydroxyl group in a side chain, a light-transmitting resin, a photoinitiator, and a solvent.

In one embodiment of the present invention, the polysiloxane compound having a hydroxyl group in the side chain is a component that imparts adhesion between the cycloolefin polymer substrate and the hard coating layer, and is a compound having a polysiloxane skeleton and a hydroxyl group in the side chain.

The polysiloxane compound having a hydroxyl group in the side chain may improve adhesion by hydrogen bonding with the hydroxyl group on the surface of the cycloolefin polymer substrate in which the hydroxyl group in the molecule has been hydrophilized.

The polysiloxane compound having a hydroxyl group in the side chain is a hydrolyzable trialkoxysilane or tetraalkoxysilane condensation polymer, and is not particularly limited as long as it has a hydroxyl group in the side chain, but a tetraalkoxysilane condensation polymer is preferable in terms of securing adhesion.

Examples of the hydrolyzable trialkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, Butyltriethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dode monoalkyltrialkoxysilanes such as siltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, and octadecyltriethoxysilane; monoaryltrialkoxysilanes such as phenyltrimethoxysilane and phenyltriethoxysilane; monovinyl trialkoxy silanes such as vinyl trimethoxysilane and vinyl triethoxysilane; monoaminoalkyl trialkoxysilanes such as γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane; monoepoxyalkyl trialkoxysilanes such as γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane; Mono (meth)acryloxyalkyl trialkoxysilane, such as (gamma)-methacryloxypropyl trimethoxysilane and (gamma)-methacryloxypropyl triethoxysilane, etc. are mentioned.

Examples of the hydrolyzable tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

The polysiloxane compound having a hydroxyl group in the side chain may be obtained and used commercially or may be prepared and used according to a known polycondensation method.

Specifically, in the polysiloxane compound having a hydroxyl group in the side chain, hydrolyzable trialkoxysilane or tetraalkoxysilane is put in an alcohol solvent (eg, methanol, ethanol, etc.), and polycondensation reaction in the presence of water and an acid catalyst (hydrochloric acid, nitric acid, etc.) It can be obtained by

Examples of commercially available products of the polysiloxane compound having a hydroxyl group in the side chain include Colcoat N-103X and Colcoat PX from Colcoat.

The polysiloxane compound having a hydroxyl group in the side chain may be included in an amount of 10 to 90 wt%, preferably 15 to 80 wt%, based on 100 wt% of the total solid content in the composition for forming an easily adhesive layer. If the content of the polysiloxane compound having a hydroxyl group in the side chain is less than 10% by weight, a sufficient bond with the cycloolefin-based substrate may not be formed and poor adhesion may occur, and if it exceeds 90% by weight, a sufficient bond with the hard coating layer cannot be formed Adhesion failure may occur.

In one embodiment of the present invention, the light-transmitting resin is a photocurable resin, and the photocurable resin may include a photocurable (meth)acrylate oligomer and/or monomer.

As the photocurable (meth)acrylate oligomer, epoxy (meth)acrylate, urethane (meth)acrylate, etc. are commonly used, and urethane (meth)acrylate is preferable. Urethane (meth)acrylate can be prepared by reacting (meth)acrylate having a hydroxyl group in a molecule and a compound having an isocyanate group in the presence of a catalyst. Specific 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, caprolactone ring-opened hydroxy acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. In addition, specific examples of the compound having an isocyanate group include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, 1, 5-diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis(isocyanatomethyl)cyclohexane, trans-1,4-cyclohexene diisocyanate, 4,4 '-Methylenebis(cyclohexyl isocyanate), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethylxylene-1, 3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenylisocyanate), 4,4'-oxybis(phenylisocyanate), hexamethylenediisocyanate There are trifunctional isocyanates derived from , trimethanol propanol adduct toluene diisocyanate, and the like.

As the monomer, those commonly used can be used without limitation, and a monomer having an unsaturated group such as a (meth)acryloyl group, a vinyl group, a styryl group, and an allyl group in the molecule as a photocurable functional group is preferable, and among them, (meth) A monomer having an acryloyl group is preferred.

The monomer having the (meth) acryloyl group is, for example, neopentyl glycol acrylate, 1,6-hexanediol di (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylic Rate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate , pentaglycerol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipenta Erythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tri(meth)acrylate, tripentaerythritol hexa(meth)acrylate, bis(2-hydroxyethyl)isocyanurate Di (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth) acrylate, isodexyl (meth) acrylate, At least one member may be selected from the group consisting of stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (meth) acrylate and isoborneol (meth) acrylate.

The light-transmitting resin exemplified above may be used alone or in combination of two or more of the photocurable (meth)acrylate oligomer and monomer.

The light-transmitting resin is not particularly limited, but may be included in an amount of 1 to 80% by weight based on 100% by weight of the total solid content in the composition for forming an easily adhesive layer. If the content of the light-transmitting resin is less than 1 wt %, a sufficient bond with the hard coating layer may not be formed, resulting in poor adhesion. A sufficient bond with the substrate may not be formed, and thus poor adhesion may occur.

In one embodiment of the present invention, the photoinitiator may be used without limitation as long as it is used in the art as one capable of forming a radical by irradiation with light. For example, hydroxy ketones, amino ketones, hydrogen recovery type photoinitiators, etc. can be used.

Specifically, the photoinitiator is 2-methyl-1-[4-(methylthio)phenyl]2-morpholinepropanone-1, diphenylketone, benzyldimethylketal, 2-hydroxy-2-methyl-1- Phenyl-1-one, 2,2-dimethoxy-2-phenyl-acetophenone, anthraquinone, fluorene, triphenylamine, carbazole, 3-methylacetophenone, 4-chloroacetophenone, 4,4-dime oxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexylphenyl ketone, benzophenone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and the like. The photoinitiators exemplified above may be used alone or in mixture of two or more.

The content of the photoinitiator is not particularly limited, and for example, 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 solid content in the composition for forming an easily adhesive layer. If the content of the photoinitiator is less than 0.1% by weight, the curing rate of the composition is slow and non-curing occurs, and the mechanical properties of the coating layer are deteriorated. If it is more than 10% by weight, cracks may occur in the coating film due to overcuring.

The solvent may be used without limitation as long as it is used in the art. Specifically, alcohol-based (methanol, ethanol, isopropanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), ketone-based (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), acetates (ethyl acetate, propyl acetate, normal butyl acetate, tert-butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, Propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate, etc.), hexane (hexane, heptane, octane, etc.), benzene type (benzene, toluene, xylene, etc.), ether (diethylene glycol dimethyl ether) , diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, etc.) may be used. Each of the solvents exemplified above may be used alone or in combination of two or more.

The solvent may be included in an amount of 10 to 95% by weight based on 100% by weight of the total composition for forming an easily adhesive layer. When the content of the solvent is less than 10% by weight, the viscosity is high, so workability is deteriorated, and the swelling of the base film cannot be sufficiently progressed. There is this.

The composition for forming an easily adhesive layer according to an embodiment of the present invention may further include a leveling agent in order to impart smoothness and coatability of the coating film during coating.

As the leveling agent, commercially available silicone type leveling agents, fluorine type leveling agents, acrylic polymer type leveling agents, etc. may be used, for example, BYK-306, BYK-307, BYK-310, BYK of BYK Chem. -313, BYK-323, BYK-331, BYK-333, BYK-337, BYK-371, BYK-373, BYK-375, BYK-377, BYK-378, BYK-3440, BYK-3570, BYK-UV3500 , BYK-UV3530, BYK-UV3570, TEGO Glide 410, TEGO Glide 411, TEGO Glide 415, TEGO Glide 420, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 455, TEGO Rad 2100 , TEGO Rad 2200N, TEGO Rad 2250, TEGO Rad 2300, TEGO Rad 2500, 3M's FC-4430, FC-4432, etc. can be used. The leveling agent may be included in an amount of 0.1 to 3% by weight based on 100% by weight of the total composition for forming an easily adhesive layer.

The composition for forming an easily adhesive layer according to an embodiment of the present invention may be used between the cycloolefin polymer substrate and the hard coating layer. The composition for forming an easily adhesive layer according to an embodiment of the present invention includes a polysiloxane compound having a hydroxyl group in a side chain and a light-transmitting resin, thereby securing adhesion through hydrogen bonding between the hydroxyl group and the hydroxyl group of the polysiloxane on the surface of the hydrophilic treated cycloolefin polymer substrate. At the same time, the unreacted light-transmitting resin of the easily adhesive layer participates in the UV curing reaction when the hard coating layer is formed to secure adhesion with the hard coating layer. Accordingly, by applying the composition for forming an easily adhesive layer according to an embodiment of the present invention between the cycloolefin polymer substrate and the hard coating layer, it is possible to provide a hard coating film having excellent flex resistance.

Accordingly, one embodiment of the present invention relates to a hard coating film formed using the above-described composition for forming an easily adhesive layer.

Hard coating film according to an embodiment of the present invention

a cycloolefin polymer substrate;

An easily adhesive layer formed on at least one surface of the cycloolefin polymer substrate, and

As a hard coating film comprising a hard coating layer formed on the easily adhesive layer,

The easily-adhesive layer is formed using the above-described composition for forming an easily-adhesive layer.

The hard coating film according to an embodiment of the present invention has excellent transmittance characteristics and bending resistance. Specifically, the hard coating film according to an embodiment of the present invention has a total light transmittance of 90% or more, and the hard coating film is repeated 200,000 times with a radius of curvature of 1 mm so that the hard coating layer is folded inward. Breakage or peeling of the hard coating layer may not occur.

The total light transmittance (Tt, %) is calculated by Equation 1 below by measuring the _{incident light intensity (T 0} ) and the total light intensity (T _{1 ) transmitted through the hard coating film.}

[Equation 1]

Total light transmittance (Tt, %) = (T ₁ /T ₀ )×100

The total light transmittance may be measured using, for example, a haze meter (Murakami Corporation) according to the method described in Experimental Examples to be described later.

In one embodiment of the present invention, the cycloolefin polymer substrate serves as a base substrate of the hard coating film, and includes a cycloolefin polymer (Cyclo Olefin Polymer, COP) and has excellent transparency.

The COP is a general term for a resin prepared through polymerization of a cyclic olefin as a monomer, and specific examples thereof include a ring-opened (co)polymer of a cyclic olefin; addition polymers of cyclic olefins; copolymers of cyclic olefins and ?-olefins such as ethylene or propylene (usually random copolymers); graft-modified products each modified with an unsaturated carboxylic acid or a derivative thereof; and hydrides thereof. Specific examples of the cyclic olefin include a norbornene-based monomer.

Specifically, the COP may be a polymer obtained by selectively hydrogenating one or more of the monomers represented by the following Chemical Formulas 1 to 3 through a ring-opening metathesis polymerization.

[Formula 1]

[Formula 2]

[Formula 3]

The process of preparing COP from ring-opening polymerization of one or more of the monomers represented by Chemical Formulas 1 to 3 can be easily performed according to a conventional method.

For example, palladium (II) acetylacetonate [Pd(acac) ₂ ] and tricyclohexylphosphine are used as polymerization catalysts, and dimethylanilinium tetrakis (pentafluorophenyl) borate [dimethylanilinium tetrakiss ( pentafluorophenyl)borate] can be used to carry out the polymerization process.

In one embodiment of the present invention, the COP may be prepared by mixing other ring-opening polymerizable cyclic olefins other than the norbornene-based monomer without detracting from the object of the present invention. Specific examples of such cyclic olefins include compounds having one reactive double bond, such as cyclopentene, cyclooctene, and 5,6-dihydrodicyclopentadiene.

The COP may be further hydrogenated after ring opening polymerization. The hydrogenation may be carried out by reacting with hydrogen gas in the presence of a hydrogenation catalyst according to a method known in the art. The hydrogenation rate is preferably 90% or more, more preferably 95% or more, still more preferably 99% or more. A hydrogenation rate within the above range may provide excellent heat degradation resistance, light degradation resistance, and the like.

For the above COP, various products are commercially available. Specific examples of the COP include trade names "ZF-16", "ZEONEX" and "ZEONOR" manufactured by ZEON CORPORATION, respectively, trade names "Arton" manufactured by JSR Corporation, trade names "TOPAS" manufactured by TICONA Corporation, and the trade name "APEL" manufactured by Mitsui Chemicals, Inc.

Any suitable molding method may be employed as a method of forming the base film from the above COP. Specific examples thereof include a compression molding method, a transfer molding method, an injection molding method, an extrusion molding method, a blow molding method, a powder molding method, a FRP molding method, and a casting method. The extrusion molding method and the casting method are preferable because the obtained film can have improved smoothness and good optical uniformity. Molding conditions may be appropriately set according to the composition or type of the resin used, properties desired for the optical film, and the like.

The thickness of the cycloolefin polymer substrate is not particularly limited, but may be 10 to 1000 μm, specifically 20 to 150 μm. If the thickness of the transparent substrate is less than 10㎛, the strength of the film is lowered and workability is deteriorated, and if it exceeds 1000㎛, there is a problem that the transparency is lowered or the weight of the hard coating film is increased.

In one embodiment of the present invention, the cycloolefin polymer substrate may be hydrophilized.

The hydrophilic treatment may be performed by a surface treatment method such as corona or plasma treatment.

In one embodiment of the present invention, the above-described composition for forming an easily adhesive layer is applied to at least one surface of the cycloolefin polymer substrate and cured to form an easily adhesive layer.

The composition for forming an easily adhesive layer according to an embodiment of the present invention is coated on a substrate by appropriately using known methods such as die coater, air knife, reverse roll, spray, blade, casting, gravure, micro gravure, spin coating, etc. process) is possible.

After the composition for forming an easily adhesive layer is applied to the substrate, the solvent is evaporated to dryness, and then cured by irradiating UV light. The irradiation amount of the UV light may specifically be about 10 to 500 mJ/cm 2 , more specifically 50 to 400 mJ/cm 2 .

At this time, the thickness of the easily-adhesive layer to be formed may be specifically 0.1 to 5㎛, more specifically 0.3 to 3㎛. When the thickness of the easily adhesive layer is included within the above range, excellent adhesion and bending resistance can be obtained.

In one embodiment of the present invention, the hard coating layer may be formed using a hard coating composition comprising a light-transmitting resin, a photoinitiator and a solvent.

The light-transmitting resin may be a photo-curable resin, and the photo-curable resin may include a photo-curable (meth)acrylate oligomer and/or monomer. The light-transmitting resin preferably includes at least one selected from the group consisting of a photocurable (meth)acrylate oligomer and a monomer having a (meth)acryloyl group in terms of adhesion to the easily adhesive layer.

Specific types of the photocurable (meth)acrylate oligomer and the monomer having a (meth)acryloyl group may be the same as those used in the composition for forming an easily adhesive layer described above.

In addition, as the monomer having a (meth)acryloyl group, a dendrimer compound having a (meth)acrylate end group may be used.

The dendrimer compound having the (meth) acrylate end group may be used for UV curing by replacing the end of the branched structure with a (meth) acrylate group, and the center thereof is completely aliphatic and has a structural feature consisting of a tertiary ester bond. . Therefore, the dendrimer compound having the (meth) acrylate end group has a structural feature of having more functional groups compared to molecular weight with the increase of generation compared to general polyfunctional acrylate monomers, and the core portion during curing by distributing functional groups at the ends This can contribute to the improvement of the bending property. Accordingly, it is possible to obtain a high hardness hard coating film with improved curl and flexibility.

The dendrimer compound having the (meth)acrylate end group may be obtained commercially or may be prepared according to a method known in the art. For example, a first-generation dendrimer structure is formed by condensation reaction with dimethylolpropionic acid using a specific polyhydric alcohol as a central skeleton, and then the dimethylolpropionic acid as a branched structure is repeatedly subjected to condensation reaction to grow into a second-generation or higher structure. , it is possible to obtain a dendrimer compound highly branched and substituted with a plurality of (meth)acrylate groups at the terminal groups by condensation reaction of acrylic acid.

The light-transmitting resin is not particularly limited, but may be included in an amount of 1 to 80% by weight based on 100% by weight of the total hard coating composition. If it is less than 1% by weight, it is difficult to achieve sufficient hardness improvement, and if it exceeds 80% by weight, there is a problem in that curling becomes severe.

The photoinitiator may be the same as that used in the composition for forming an easily adhesive layer described above.

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 coating composition. When the content of the photoinitiator is less than 0.1% by weight, the curing rate of the composition is slow and non-curing occurs, so that mechanical properties are deteriorated, and when the content of the photoinitiator is more than 10% by weight, cracks may occur in the coating film due to overcuring.

The solvent may be the same as that used in the composition for forming an easily adhesive layer described above.

In addition, the solvent may include a fluorine-based solvent. The fluorine-based solvent increases the solubility of the fluorine-based UV-curable functional group-containing compound, which will be described later, and thus not only maintains the wetting properties of the prepared hard coating film and the coating film state of the film, but also enhances the fluorine-based UV-curable functional group in the coating and drying process. It can serve to form a high-concentration fluorine component layer on the surface of the prepared hard coat layer by aligning it to the surface of the hard coat layer.

As the fluorine-based solvent, perfluorohexylethyl alcohol, perfluoroether, perfluorohexane, etc. can be used, and commercially available products include 3M's HFE-7100, HFE-7300, HFE-7500, FC-3283, FC- 40, FC-770, and C6FOH-BF from Nika Corporation, but are not limited thereto.

The solvent may be included in an amount of 5 to 90% by weight, preferably 7 to 85% by weight, based on 100% by weight of the total hard coating composition. If it is less than 5% by weight, the viscosity is high and workability is lowered, and if it is more than 90% by weight, it is difficult to adjust the thickness of the coating film, and there is a disadvantage that the appearance is poor due to the occurrence of dry stains.

In one embodiment of the present invention, the hard coating composition may further include a fluorine-based UV-curable functional group-containing compound.

The fluorine-based UV-curable functional group-containing compound is not particularly limited as long as it contains fluorine and has a UV-curable functional group as a component imparting antifouling and abrasion resistance.

The fluorine-based UV-curable functional group-containing compound is (meth)acrylate containing a perfluoroalkyl group, (meth)acrylate containing a perfluoropolyether group, and (meth)acrylate containing a perfluorocyclic aliphatic group And one or more selected from the group consisting of (meth)acrylate containing a perfluoroaromatic group can be used, and in this case, it shows excellent antifouling performance and at the same time forms a chemical bond with the hard coating layer to improve antifouling performance even after repeated use It is preferable because it has the advantage of excellent durability to be maintained for a long time.

The fluorine-based UV-curable functional group-containing compound may be included in an amount of 0.01 to 30% by weight, preferably 0.01 to 20% by weight, more preferably 0.01 to 10% by weight based on 100% by weight of the total solid content in the hard coating composition. can When the fluorine-based UV-curable functional group-containing compound is included within the above range, it is preferable because excellent abrasion resistance and antifouling effect can be imparted. When the content of the UV-curable functional group-containing compound is less than the above range, it may be somewhat difficult to sufficiently achieve abrasion resistance or antifouling properties, and if it exceeds the above range, film hardness or scratch resistance may be slightly reduced.

In addition to the above components, the hard coating composition may further include components commonly used in the art, for example, a leveling agent, a UV stabilizer, a heat stabilizer, an antioxidant, a surfactant, a lubricant, an antifouling agent, and the like. .

The hard coating film according to an embodiment of the present invention may be prepared by applying and curing the hard coating composition on an easily adhesive layer formed on at least one surface of a cycloolefin polymer substrate to form a hard coating layer.

The hard coating composition can be coated on the easily adhesive layer by appropriately using a known method such as a die coater, an air knife, a reverse roll, spray, blade, casting, gravure, micro gravure, or spin coating.

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

At this time, the thickness of the formed hard coating layer may be specifically 2 to 30㎛, more specifically 3 to 20㎛. When the thickness of the hard coating layer is included in the above range, excellent hardness and bending resistance can be obtained.

One embodiment of the present invention relates to an image display device provided with the above-described hard coating film. As an example, the hard coating film of the present invention may be used as a window of an image display device, particularly a flexible display device or a foldable display device. In addition, the hard coating film of the present invention may be used by attaching it to a polarizing plate, a touch sensor, or the like.

The hard coating film according to an embodiment of the present invention may be used in LCDs of various driving methods such as reflective, transmissive, transflective LCD or TN type, STN type, OCB type, HAN type, VA type, IPS type, and the like. In addition, the hard coating film according to an embodiment of the present invention may be used in various image display devices such as a plasma display, a field emission display, an organic EL display, an inorganic EL display, and electronic paper.

Hereinafter, the present invention will be described in more detail by way of Examples, Comparative Examples and Experimental Examples. These Examples, Comparative Examples, and Experimental Examples are only for illustrating the present invention, and it is apparent to those skilled in the art that the scope of the present invention is not limited thereto.

Preparation Example 1: Preparation of a composition for forming an easily adhesive layer

60 parts by weight polysiloxane compound having a hydroxyl group in the side chain (Colcoat, Colcoat N-103X, solid content 2% by weight), 6 parts by weight trifunctional acrylate monomer (Miwon, Miramer M340), 33.4 parts by weight methyl ethyl ketone, 0.3 weight Part 1-hydroxycyclohexylphenyl ketone and 0.3 parts by weight of a leveling agent (BYK, BYK UV-3530) were blended using a stirrer and filtered using a PP filter to prepare a composition for forming an easily adhesive layer.

Preparation Example 2: Preparation of a composition for forming an easily adhesive layer

90 parts by weight polysiloxane compound having a hydroxyl group in the side chain (Colcoat, Colcoat N-103X, solid content 2% by weight), 6 parts by weight trifunctional acrylate monomer (Miwon, Miramer M340), 3.4 parts by weight methyl ethyl ketone, 0.3 weight Part 1-hydroxycyclohexylphenyl ketone and 0.3 parts by weight of a leveling agent (BYK, BYK UV-3530) were blended using a stirrer and filtered using a PP filter to prepare a composition for forming an easily adhesive layer.

Preparation Example 3: Preparation of a composition for forming an easily adhesive layer

60 parts by weight polysiloxane compound having a hydroxyl group in the side chain (Colcoat, Colcoat PX, solid content 2% by weight), 6 parts by weight trifunctional acrylate monomer (Miwon, Miramer M340), 33.4 parts by weight methyl ethyl ketone, 0.3 parts by weight 1 -Hydroxycyclohexylphenylketone and 0.3 parts by weight of a leveling agent (BYK, BYK UV-3530) were blended using a stirrer and filtered using a PP filter to prepare a composition for forming an easily adhesive layer.

Preparation Example 4: Preparation of a composition for forming an easily adhesive layer

90 parts by weight polysiloxane compound having a hydroxyl group in the side chain (Colcoat, Colcoat PX, solid content 2% by weight), 6 parts by weight trifunctional acrylate monomer (Miwon, Miramer M340), 3.4 parts by weight methyl ethyl ketone, 0.3 parts by weight 1 -Hydroxycyclohexylphenylketone and 0.3 parts by weight of a leveling agent (BYK, BYK UV-3530) were blended using a stirrer and filtered using a PP filter to prepare a composition for forming an easily adhesive layer.

Preparation Example 5: Preparation of a composition for forming an easily adhesive layer

100 parts by weight of a polysiloxane compound having a hydroxyl group in the side chain (Colcoat, Colcoat N-103X, solid content 2% by weight) was filtered using a PP filter to prepare a composition for forming an easily adhesive layer.

Preparation 6: Preparation of a composition for forming an easily adhesive layer

100 parts by weight of a polysiloxane compound having a hydroxyl group in the side chain (Colcoat, Colcoat PX, solid content 2% by weight) was filtered using a PP filter to prepare a composition for forming an easily adhesive layer.

Preparation Example 7: Preparation of a composition for forming an easily adhesive layer

10 parts by weight polysiloxane compound having a hydroxyl group in the side chain (Colcoat, Colcoat N-103X, solid content 2% by weight), 6 parts by weight trifunctional acrylate monomer (Miwon, Miramer M340), 83.4 parts by weight methyl ethyl ketone, 0.3 weight Part 1-hydroxycyclohexylphenyl ketone and 0.3 parts by weight of a leveling agent (BYK, BYK UV-3530) were blended using a stirrer and filtered using a PP filter to prepare a composition for forming an easily adhesive layer.

Preparation Example 8: Preparation of a composition for forming an easily adhesive layer

10 parts by weight polysiloxane compound having a hydroxyl group in the side chain (Colcoat, Colcoat PX, solid content 2% by weight), 6 parts by weight trifunctional acrylate monomer (Miwon, Miramer M340), 83.4 parts by weight methyl ethyl ketone, 0.3 parts by weight 1 -Hydroxycyclohexylphenylketone and 0.3 parts by weight of a leveling agent (BYK, BYK UV-3530) were blended using a stirrer and filtered using a PP filter to prepare a composition for forming an easily adhesive layer.

Preparation Example 9: Preparation of a hard coating composition

23 parts by weight 6-functional urethane acrylate (Shin-Nakamura Chemical, U-6LPA), 23 parts by weight 14-functional acrylate (Osaka Yuki Chemical, VISCOAT #1000), 5 parts by weight fluorine-based solvent (Nika, C6FOH-BF), 45 Methyl ethyl ketone, 3.5 parts by weight 1-hydroxycyclohexylphenyl ketone, and 0.5 parts by weight fluorine-based UV-curable functional group-containing compound (Shin-Etsu Corporation, KY-1203) are blended using a stirrer and filtered using a PP filter. to prepare a hard coating composition.

Example 1: Preparation of easily adhesive film

After curing the composition for forming an easily adhesive layer of Preparation Example 1 on a film whose surface water contact angle was adjusted to a level of 65 degrees by corona treatment of a cycloolefin film (COP, ZF-14, 23 μm by Xeon Corporation), a thickness of 0.5 μm was obtained. After coating as much as possible, drying the solvent, and irradiating 300 mJ/cm 2 of accumulated UV light in a nitrogen atmosphere to prepare an easily adhesive film.

Example 2: Preparation of easily adhesive film

An easily adhesive film was prepared in the same manner as in Example 1, except that the composition for forming an easily adhesive layer of Preparation Example 2 was used instead of the composition for forming an easily adhesive layer of Preparation Example 1.

Example 3: Preparation of easily adhesive film

An easily adhesive film was prepared in the same manner as in Example 1, except that the composition for forming an easily adhesive layer of Preparation Example 3 was used instead of the composition for forming an easily adhesive layer of Preparation Example 1.

Example 4: Preparation of easily adhesive film

An easily adhesive film was prepared in the same manner as in Example 1, except that the composition for forming an easily adhesive layer of Preparation Example 4 was used instead of the composition for forming an easily adhesive layer of Preparation Example 1.

Example 5: Preparation of hard coating film

After curing the hard coating composition of Preparation Example 9 on the easily-adhesive layer of the easily-adhesive film prepared in Example 1, the coating was coated to a thickness of 5 μm, the solvent was dried, and the UV accumulated light amount of 600 mJ/cm 2 was irradiated under a nitrogen atmosphere. to prepare a hard coating film.

Example 6: Preparation of hard coating film

A hard coating film was prepared in the same manner as in Example 5, except that the easily adhesive film prepared in Example 2 was used instead of the easily adhesive film prepared in Example 1 above.

Example 7: Preparation of hard coating film

A hard coating film was prepared in the same manner as in Example 5, except that the easily adhesive film prepared in Example 3 was used instead of the easily adhesive film prepared in Example 1 above.

Example 8: Preparation of hard coating film

A hard coating film was prepared in the same manner as in Example 5, except that the easily adhesive film prepared in Example 4 was used instead of the easily adhesive film prepared in Example 1 above.

Comparative Example 1: Preparation of easily adhesive film

An easily adhesive film was prepared in the same manner as in Example 1, except that the composition for forming an easily adhesive layer of Preparation Example 5 was used instead of the composition for forming an easily adhesive layer of Preparation Example 1.

Comparative Example 2: Preparation of an easily adhesive film

An easily adhesive film was prepared in the same manner as in Example 1, except that the composition for forming an easily adhesive layer of Preparation Example 6 was used instead of the composition for forming an easily adhesive layer of Preparation Example 1.

Comparative Example 3: Preparation of easily adhesive film

An easily adhesive film was prepared in the same manner as in Example 1, except that the composition for forming an easily adhesive layer of Preparation Example 7 was used instead of the composition for forming an easily adhesive layer of Preparation Example 1.

Comparative Example 4: Preparation of an easily adhesive film

An easily adhesive film was prepared in the same manner as in Example 1, except that the composition for forming an easily adhesive layer of Preparation Example 8 was used instead of the composition for forming an easily adhesive layer of Preparation Example 1.

Comparative Example 5: Preparation of hard coating film

A hard coating film was prepared in the same manner as in Example 5, except that the easily adhesive film prepared in Comparative Example 1 was used instead of the easily adhesive film prepared in Example 1 above.

Comparative Example 6: Preparation of hard coating film

A hard coating film was prepared in the same manner as in Example 5, except that the easily adhesive film prepared in Comparative Example 2 was used instead of the easily adhesive film prepared in Example 1 above.

Comparative Example 7: Preparation of hard coating film

A hard coating film was prepared in the same manner as in Example 5, except that the easily adhesive film prepared in Comparative Example 3 was used instead of the easily adhesive film prepared in Example 1 above.

Comparative Example 8: Preparation of hard coating film

A hard coating film was prepared in the same manner as in Example 5, except that the easily adhesive film prepared in Comparative Example 4 was used instead of the easily adhesive film prepared in Example 1 above.

Experimental Example 1:

The physical properties of the films prepared in Examples and Comparative Examples were measured by the method described below, and the results are shown in Table 1 below.

(1) Adhesion

After bonding the base film to the glass using a transparent adhesive so that the coated side goes upward, use a cutter knife to make scratches on the coated side in the form of 100 horizontal and vertical squares at 1 mm intervals, and then use 3 A spin adhesive test was performed.

The evaluation result was expressed as "the number of squares that are OK after the adhesion test/100".

(2) Total light transmittance (Tt) and haze

The total light transmittance (%) and haze (%) of the coating film were measured using a haze meter HM-150 manufactured by Murakami Corporation.

(3) Water contact angle

The contact angle of water was measured using KRUSS's contact angle measuring instrument DSA100. At room temperature, the amount of droplet was 3 μl.

(4) wear resistance

Measurements were made using a wear-resistance measuring device of Daesung Precision Co., Ltd. The contact angle was measured after rubbing the coating surface 3000 times using an abrasion-resistant eraser and 500 g of weight. In this case, the case where the contact angle of water is 100° or more as the evaluation criterion was selected as the abrasion resistance acceptance criterion.

<Evaluation criteria>

○: contact angle of 100˚ or more

×: the contact angle is less than 100˚

(5) Chemical resistance

Measurements were made using a wear-resistance measuring device of Daesung Precision Co., Ltd. After adding 99.9% ethanol dropwise to the coating surface, the area where the ethanol fell was rubbed 3000 times using an abrasion-resistant eraser and 500 g of weight, and then the contact angle was measured. Ethanol was continuously added dropwise to prevent ethanol volatilization during evaluation. After the evaluation was completed, ethanol was removed and the water contact angle was measured. In this case, the case where the contact angle of water is 95˚ or more as the evaluation criterion was selected as the chemical resistance acceptance criterion.

<Evaluation criteria>

○: contact angle of 95˚ or more

×: the contact angle is less than 95˚

(6) scratch resistance

After bonding the base film to the glass using a transparent adhesive so that the coating surface is on the top, using steel wool (#0000) at a load of 500 g/cm 2 and reciprocating friction 10 times, the measuring part is transmitted and reflected by a three-wavelength lamp Thus, scratches were observed. The scratch resistance was evaluated according to the following evaluation criteria.

<Evaluation criteria>

○: Scratch is not recognized or less than 10 scratches are recognized

×: more than 10 scratches were recognized

(7) Flexural resistance

By repeating the film folding and unfolding test 200,000 times with a radius of curvature of 1 mm so that the hard coating layer is folded inward, whether the film is broken and whether the hard coating layer is peeled off was observed. Flexural resistance was evaluated according to the following evaluation criteria.

<Evaluation criteria>

○: Film breakage and hard coating layer peeling did not occur

×: film breakage or hard coating layer peeling occurred

	adhesion	Tt (%)	Haze (%)	Water contact angle (°)	wear resistance	chemical resistance	scratch resistance	Flexibility
Example 1	100/100	-	-	-	-	-	-	-
Example 2	100/100	-	-	-	-	-	-	-
Example 3	100/100	-	-	-	-	-	-	-
Example 4	100/100	-	-	-	-	-	-	-
Example 5	100/100	90.8	0.3	111.2	○	○	○	○
Example 6	100/100	91.2	0.2	110.5	○	○	○	○
Example 7	100/100	90.5	0.2	112.1	○	○	○	○
Example 8	100/100	90.6	0.3	111.8	○	○	○	○
Comparative Example 1	100/100	-	-	-	-	-	-	-
Comparative Example 2	100/100	-	-	-	-	-	-	-
Comparative Example 3	15/100	-	-	-	-	-	-	-
Comparative Example 4	20/100	-	-	-	-	-	-	-
Comparative Example 5	0/100	90.4	0.2	111.5	○	○	○	×
Comparative Example 6	0/100	90.8	0.3	112.2	○	○	○	×
Comparative Example 7	17/100	91.1	0.3	111.4	○	○	○	×
Comparative Example 8	18/100	91.2	0.3	110.6	○	○	○	×

As shown in Table 1, according to the present invention, the easily adhesive films of Examples 1 to 4 prepared by using the composition for forming an easily adhesive layer of Preparation Examples 1 to 4 comprising a polysiloxane compound having a hydroxyl group in a side chain and a light-transmitting resin according to the present invention. It can be seen that the adhesion of the coating surface is excellent. In addition, it can be confirmed that the hard coating films of Examples 5 to 8, in which the hard coating layer is formed on the easily adhesive film of Examples 1 to 4, are excellent in water contact angle, abrasion resistance, chemical resistance, scratch resistance and bending resistance as well as adhesion. there was.

On the other hand, the easily adhesive films of Comparative Examples 1 and 2 prepared by using the compositions for forming an easily adhesive layer of Preparation Examples 5 to 6 that include a polysiloxane compound having a hydroxyl group in the side chain but do not include a light-transmitting resin have good adhesion to the coating surface. However, it was confirmed that the hard coating films of Comparative Examples 5 to 6, in which the hard coating layer was formed on the easily adhesive film of Comparative Examples 1 and 2, were inferior in not only adhesion of the coating surface but also in bending resistance. In addition, the easily adhesive films of Comparative Examples 3 to 4 prepared using the compositions for forming an easily adhesive layer of Preparation Examples 7 to 8 having a low content of the polysiloxane compound having a hydroxyl group in the side chain have poor adhesion to the coating surface, Comparative Example 3 It was confirmed that the hard coating films of Comparative Examples 7 to 8 in which the hard coating layer was formed on the easily adhesive film of to 4 were not only adhesive of the coating surface but also had poor bending resistance.

As the specific part of the present invention has been described in detail above, for those of ordinary skill in the art to which the present invention pertains, it is clear that these specific techniques are only preferred embodiments, and the scope of the present invention is not limited thereto. do. Those of ordinary skill in the art to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above contents.

Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (13)

1. A composition for forming an easily adhesive layer comprising a polysiloxane compound having a hydroxyl group in a side chain, a light-transmitting resin, a photoinitiator, and a solvent.
2. The composition for forming an easily adhesive layer according to claim 1, wherein the polysiloxane compound having a hydroxyl group in the side chain is included in an amount of 10 to 90 wt% based on 100 wt% of the total solid content of the composition for forming an easily adhesive layer.
3. The composition for forming an easily adhesive layer according to claim 1, wherein the light-transmitting resin comprises at least one selected from the group consisting of photocurable (meth)acrylate oligomers and monomers.
4. The composition for forming an easily adhesive layer according to claim 1, wherein the composition for forming an easily adhesive layer is used between the cycloolefin polymer substrate and the hard coating layer.
5. a cycloolefin polymer substrate;

   An easily adhesive layer formed on at least one surface of the cycloolefin polymer substrate, and

   As a hard coating film comprising a hard coating layer formed on the easily adhesive layer,

   The hard coating film that the easily adhesive layer is formed using the composition for forming an easily adhesive layer according to any one of claims 1 to 4.
6. The method according to claim 5, wherein the total light transmittance is 90% or more,

   A hard coating film that does not cause breakage of the hard coating film or peeling of the hard coating layer after folding and unfolding the hard coating film by repeating 200,000 times with a radius of curvature of 1 mm so that the hard coating layer is folded inward.
7. The hard coating film of claim 5, wherein the cycloolefin polymer substrate is hydrophilic treated.
8. The hard coating film of claim 5, wherein the hard coating layer is formed using a hard coating composition comprising a light-transmitting resin, a photoinitiator, and a solvent.
9. The hard coating film of claim 8, wherein the light-transmitting resin comprises at least one selected from the group consisting of photocurable (meth)acrylate oligomers and monomers.
10. An image display device provided with the hard coating film according to claim 5 .
11. A window of a flexible display device provided with the hard coating film according to claim 5 .
12. A polarizing plate provided with the hard coating film according to claim 5 .
13. A touch sensor having a hard coating film according to claim 5 .