KR20190048916A - Composition for window film, flexible window film prepared using the same and optical display comprising the same - Google Patents

Abstract

Provided are: a composition for a window film comprising an epoxy-based silicone resin of chemical formula 1: (R^1SiO_3/2)_x(R^2SiO_3/2)_y(R^3R^4SiO_2/2)_z(SiO_4/2)_w; an epoxy-based monomer, a (meth) acrylate monomer, and an initiator, wherein the (meth) acrylate monomer is non-reactive with respect to each of the epoxy-based silicone resin and the epoxy-based monomer, and a total epoxy-based silicone resin and the epoxy-based monomer: a weight ratio of the (meth) acrylate-based monomer is 80:20 to 99.5:0.5, based on 100 parts by weight of the sum of the epoxy-based silicone resin, the epoxy-based monomer, and the (meth) acrylate-based monomer; a flexible window film formed from the same; and an optical display device comprising the same. The present invention provides the composition for the window film capable of realizing a coating layer excellent in hardness and flexibility.

Description

TECHNICAL FIELD [0001] The present invention relates to a composition for a window film, a flexible window film formed therefrom, and an optical display device including the window film. BACKGROUND OF THE INVENTION 1. Field of the Invention [0002]

The present invention relates to a composition for a window film, a flexible window film formed therefrom, and an optical display device comprising the same.

Flexible display devices have been developed that can be folded and unfolded while replacing a glass substrate or a hardened substrate with a film in a display device. The flexible display device is thin, light, strong against impact, and can be folded and unfolded.

Since the window film is located at the outermost portion of the display device, flexibility and hardness of the window film should be high when used in a flexible display device. The window film is composed of a base layer and a coating layer. When used in a flexible display device, the window film should be foldable towards the substrate layer or coating layer. In particular, if the window film is well folded toward the substrate layer, the display will be highly effective when it is folded toward the coating layer because not only a single viewer but also a plurality of viewers can see the display at the same time. Further, the window film is located at the outermost of the display devices. Therefore, when the scratch resistance is low, scratches may be caused by external scratches, which may deteriorate the screen quality. Particularly, when a display device is used, fine scratches caused by a hand or the like may not only deteriorate the screen quality but may deteriorate the appearance.

The background art of the present invention is disclosed in Japanese Laid-Open Patent Application No. 2007-176542.

An object of the present invention is to provide a composition for a window film capable of realizing a coating layer excellent in hardness and flexibility.

Another object of the present invention is to provide a specimen including a coating layer and a substrate layer, wherein when the specimen is folded so that the coating layer is outward and the base layer is inward, cracks are not generated in the coating layer, And to provide a composition for a film.

It is still another object of the present invention to provide a composition for a window film capable of realizing a coating layer excellent in scratch resistance.

It is still another object of the present invention to provide a flexible window film comprising a coating layer formed from the composition for a window film of the present invention.

The composition for a window film of the present invention comprises an epoxy-based silicone resin, an epoxy-based monomer, a (meth) acrylate-based monomer and an initiator represented by the following formula (1)

≪ Formula 1 >

(R ¹ SiO _3/2 ) _x (R ² SiO _3/2 ) _y (R ³ R ⁴ SiO _2/2 ) _z (SiO _4/2 ) _w

(Wherein R ¹ , R ² , R ³ , R ⁴ , x, y, z and w are as defined in the description of the present invention)

The (meth) acrylate-based monomer is non-reactive with respect to the epoxy-based silicone resin and the epoxy-based monomer, and the total sum of the epoxy-based silicone resin and the epoxy-based monomer: the weight ratio of the (meth) May be 80:20 to 99.5: 0.5 based on 100 parts by weight of the total amount of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate-based monomer.

The flexible window film of the present invention comprises a base layer and a coating layer formed on the base layer, wherein the flexible window film can have an indentation hardness of more than 45 mN / mm ² and a crack strain of 2.5% or more.

The optical display device of the present invention can include the flexible window film of the present invention.

The present invention provides a composition for a window film capable of realizing a coating layer excellent in hardness and flexibility.

The present invention relates to a composition for a window film in which a specimen including a coating layer and a substrate layer is capable of realizing a coating layer having excellent flexibility because no crack is generated in the coating layer when the coating layer is folded out so that the coating layer is inward and the substrate layer is inward Lt; / RTI >

The present invention provides a composition for a window film capable of realizing a coating layer excellent in scratch resistance.

The present invention provides a flexible window film comprising a coating layer formed from the composition for a window film of the present invention.

1 is a cross-sectional view of a flexible window film according to an embodiment of the present invention.
2 is a cross-sectional view of a flexible window film according to another embodiment of the present invention.
3 is a cross-sectional view of a flexible window film according to another embodiment of the present invention.
4 is a cross-sectional view of a display device according to an embodiment of the present invention.
5 is a cross-sectional view of a display device according to another embodiment of the present invention.
6 is a cross-sectional view of a display device according to another embodiment of the present invention.

The present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the scope of the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

The terms "upper" and "lower" in this specification are defined with reference to the drawings, wherein "upper" may be changed to "lower", "lower" What is referred to as " on " may include not only superposition, but also intervening other structures in the middle. On the other hand, what is referred to as " directly on " or " directly above "

As used herein, "(meth) acrylate" means acrylate and / or methacrylate.

As used herein, unless specifically stated otherwise, at least one hydrogen atom of the functional group may be replaced by a hydroxyl group, an unsubstituted C1 to C10 alkyl group, a C1 to C10 alkoxy group, a C3 to C10 cycloalkyl group, C20 aryl group, a C7 to C20 arylalkyl group, a C6 to C20 aryl group substituted with a C1 to C10 alkyl group, or a C1 to C10 alkyl group substituted with a C1 to C10 alkoxy group.

As used herein, " halogen " means fluorine, chlorine, bromine or iodine. In the present specification, "Ec" is a 2- (3,4-epoxycyclohexyl) ethyl group and "Gp" is a 3-glycidoxypropyl group.

In this specification, the "modulus" of the adhesive layer is a storage modulus and is measured using a dynamic viscoelasticity measuring device ARES (Anton Paar MCR-501) at a shear rate of 1 rad / sec, strain 1% The viscoelasticity was measured. After removing the release film, the adhesive layer was laminated to a thickness of 500 mu m and the laminate was punched with a perforator having a diameter of 8 mm and used as a specimen. The measurement was carried out at a temperature rise rate of 5 DEG C / min in a temperature range of -60 DEG C to 90 DEG C using an 8 mm jig, and the modulus was recorded at -20 DEG C, 25 DEG C and 80 DEG C, respectively.

The " average particle diameter " of the organic nanoparticles in the present specification is the particle diameter of the organic nanoparticles expressed by the Z-average value measured by a Zetasizer nano-ZS instrument of Malvern, .

Hereinafter, a composition for a window film according to an embodiment of the present invention will be described.

The composition for a window film may include an epoxy-based silicone resin represented by the following formula (1), an epoxy-based monomer, a (meth) acrylate-based monomer, and an initiator.

The (meth) acrylate-based monomer is non-reactive with respect to the epoxy-based silicone resin and the epoxy-based monomer, and the sum of the epoxy-based silicone resin and the epoxy-based monomer: May be in a weight ratio of 80:20 to 99.5: 0.5 based on 100 parts by weight of the sum of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate-based monomer. In the weight ratio range, the specimen having the coating layer formed of the composition for the window film on the base layer can have excellent flexibility and hardness and excellent scratch resistance.

The " flexibility " means that when the specimen is stretched at a tensile speed of 10 mm / min, the tensile elongation at the time of cracking occurs in the coating layer, and the higher the tensile elongation, the more excellent the flexibility. The hardness is the hardness measured by pressurizing the coating layer with a microindenter or a nanoindenter at a loading speed of 30 mN under a loading speed of 15 seconds, creeping for 5 seconds, and relaxation for 20 seconds in the specimen as the indentation hardness.

Out-folding of the specimen including the coating layer and the base layer such that the coating layer is outward and the base layer is inward is more effective than in-folding in which the coating layer is inward and the base layer is outward More flexible properties are required. Thus, the composition of the present invention satisfied the predetermined range when the tensile strength was evaluated by the above-mentioned tensile strength evaluation method, and thus it was possible to realize a coating layer having excellent flexibility, which is sufficiently high even in the case of out-folding. In addition, flexibility and hardness are difficult to satisfy both flexibility and hardness in a trade-off relationship. However, according to the tensile strength evaluation method, the composition of the present invention satisfies a predetermined range, thereby realizing a coating layer having excellent flexibility and sufficiently high hardness even in the case of out-folding. Particularly, when the specimen is out-folded, the coating layer is exposed to the outer surface. However, according to the scratch resistance evaluation method described below, the composition of the present invention can provide a coating layer having excellent scratch resistance.

Hereinafter, each component of the composition for a window film of the present invention will be described in detail.

Epoxy-based silicone resin

The epoxy-based silicone resin may include an epoxy-based silicone resin represented by the following Formula 1:

≪ Formula 1 >

(R ¹ SiO _3/2 ) _x (R ² SiO _3/2 ) _y (R ³ R ⁴ SiO _2/2 ) _z (SiO _4/2 ) _w

(Wherein R ¹ represents an alicyclic epoxy group-containing functional group,

R ² is a glycidyl group-containing functional group,

R ³ and R ⁴ are each independently hydrogen, an alicyclic epoxy group-containing functional group, a glycidyl group-containing functional group, an unsubstituted or substituted C 1 to C 20 alkyl group, an unsubstituted or substituted C 5 to C 20 cycloalkyl group, A substituted C6 to C20 aryl group,

0 &lt; y < 1, 0 < z &

The epoxy-based silicone resin can improve hardness and scratch resistance by reacting with an epoxy-based monomer. However, the epoxy-based silicone resin is a non-reactive resin that does not react with the (meth) acrylate-based monomer. Through this, the flexibility of the coating layer formed of the composition can be improved.

In the formula (1), 0 <y? 0.5, 0 <y? 0.3, 0 <y? 0.2, specifically 0.01? Y? 0.15. In the above range, the hardness can be high and the scratch resistance can be excellent. In particular, when 0.01? Y? 0.15, a window film having good optical transparency can be realized because the refractive index difference between the substrate layer and the substrate layer is small.

Specifically, R ¹ may be an unsubstituted or substituted C 1 to C 10 alkyl group having an alicyclic epoxy group, more specifically, an epoxycyclohexylethyl group, an epoxycyclohexylmethyl group, or an epoxycyclohexylpropyl group. The " alicyclic epoxy group " is a C5 to C10 epoxidized alicyclic group. Specifically, R ² may be an unsubstituted or substituted C 1 to C 10 alkyl group having a glycodoxy group, more specifically a glycidoxypropyl group. Specifically, R ³ and R ⁴ may each independently be a methyl group, an ethyl group, a phenyl group, an epoxycyclohexylmethyl group, an epoxycyclohexylethyl group, an epoxycyclohexylpropyl group, or a glycidoxypropyl group.

In one embodiment, the epoxy-based silicone resin of Formula 1 may be represented by Formula 1-1:

&Lt; Formula 1-1 >

(R ¹ SiO _3/2 ) _x (R ² SiO _3/2 ) _y

(Wherein R ¹ is an alicyclic epoxy group-containing functional group,

R ² is a glycidyl group-containing functional group,

0.5? X <1, 0 <y? 0.5, x + y = 1).

Preferably, 0.70? X <1, 0? Y? 0.30, specifically 0.80? X <1, 0? Y? 0.20, more specifically 0.85? X? 0.99, 0.15. In the above range, a window film having good hardness and flexibility and excellent scratch resistance can be realized. Specifically, the siloxane resin of formula (1-1) may be (EcSiO _3/2 ) _x (GpSiO _3/2 ) _y .

The epoxy-based silicone resin may have a weight average molecular weight of 1,000 g / mol to 10,000 g / mol, specifically 5,000 g / mol to 10,000 g / mol, more specifically 5,000 g / mol to 7,000 g / mol. The coating layer of the window film is supported in the above range, and the scratch resistance can be improved. The epoxy-based silicone resin may have a polydispersity (PDI) of 1.0 to 4.0, specifically 1.5 to 3.0, and an epoxy equivalent of 0.1 to 100 mol, particularly 0.3 mol / 100 g to 0.8 mol / 100 g . The coating properties are good in the range of the polydispersity and the epoxy equivalent, and the coating properties may be stable.

The epoxy-based silicone resin is preferably used in an amount of 20 to 90 parts by weight, preferably 35 to 75 parts by weight, more preferably 20 to 90 parts by weight, based on 100 parts by weight of the total of the epoxy-based silicone resin, epoxy-based monomer and (meth) 45 parts by weight to 60 parts by weight. Within the above range, the coating layer can be excellent in hardness and flexibility and excellent in scratch resistance.

The epoxy-based silicone resin may be contained in an amount of 20 to 80 parts by weight, preferably 30 to 70 parts by weight, based on 100 parts by weight of the total of the epoxy-based silicone resin and the epoxy-based monomer. Within the above range, the coating layer can be excellent in hardness and flexibility and excellent in scratch resistance.

Epoxy silicone resins (R ¹ SiO _3/2) and the silicone monomers to _{^{provide, (R 2 SiO 3/2}} ) a mixture of the silicone monomers to provide a, or said mixture and _{^{(R 3 R 4 SiO 2/}} 2) silicone monomer, to provide a (SiO _4/2) can be prepared by hydrolysis and condensation of a mixture comprising at least one of the silicon monomer to provide. Silicone monomers to provide a (R ¹ SiO _3/2) may be used for products that are sold commercially and synthesized by a conventional method, or known to those skilled in the art. For example, a trialkoxysilane compound having an R ¹ group can be used. Silicone monomers to provide a (R _² SiO _^3/2) may be used for products that are sold commercially and synthesized by a conventional method, or known to those skilled in the art. For example, a trialkoxysilane compound having an R ² group can be used. The hydrolysis and condensation reaction of the monomer mixture can be carried out according to a conventional method for producing a silicone resin. Hydrolysis may comprise reacting the monomer mixture with water and a mixture of one or more of the desired acids and bases. Specifically, the acid may be HCl, HNO ₃ , acetic acid, para-toluenesulfonic acid, and the base may be NaOH, KOH, or the like. The hydrolysis is carried out at 20 ° C to 100 ° C for 10 minutes to 10 hours, and the condensation reaction can be carried out at 20 ° C to 100 ° C for 10 minutes to 12 hours under the same conditions as the hydrolysis. The production yield of the silicone resin in the above range may be high.

Epoxy-based monomer

The epoxy-based monomer can improve the hardness and scratch resistance by reacting with the epoxy-based silicone resin. However, the epoxy-based monomer is a non-reactive monomer that does not react with the (meth) acrylate-based monomer. Through this, the (meth) acrylate-based monomer can improve the flexibility of the coating layer formed from the composition.

The epoxy-based monomer is a monomer having at least one epoxy group and is a non-silicon monomer having no silicon (Si). The epoxy-based monomer may include at least one of a chained aliphatic epoxy-based monomer, a cyclic aliphatic epoxy-based monomer, and a hydrogenated aromatic hydrocarbon epoxy-based monomer, and these may be included singly or in combination.

Examples of the chain-like aliphatic epoxy-based monomer include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol di Glycidyl ether, glycerin triglycidyl ether, polypropylene glycol diglycidyl ether; Polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin; Diglycidyl esters of aliphatic long chain dibasic acids; Monoglycidyl ethers of aliphatic higher alcohols; Glycidyl ethers of higher fatty acids; Epoxidized soybean oil; Butyl stearate; Octyl stearate; Epoxidized linseed oil; Epoxylated polybutadiene, and the like.

The cyclic aliphatic epoxy-based monomer is a compound having at least one epoxy group in the alicyclic group, and may specifically include an alicyclic epoxy carboxylate, an alicyclic epoxy (meth) acrylate, and the like. More specifically, (3,4-epoxycyclohexyl) methyl-3 ', 4'-epoxycyclohexanecarboxylate, diglycidyl 1,2-cyclohexanedicarboxylate, 2- (3,4- Epoxycyclohexyl) -5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxy-6-methylcyclohexyl) adipate, 3,4- Cyclohexylmethyl-3 ', 4'-epoxy-6'-methylcyclohexanecarboxylate, ε-caprolactone modified 3,4-epoxycyclohexylmethyl-3', 4'-epoxycyclohexanecarboxylate, trimethyl Caprolactone-modified 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, β-methyl-δ-valerolactone-modified 3,4-epoxycyclohexylmethyl- Epoxycyclohexanecarboxylate, 1,4-cyclohexanedimethanol bis (3,4-epoxycyclohexanecarboxylate), di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3, 4-epoxycyclohexane (3,4-epoxycyclohexylmethyl) adipate, 4-vinylcyclohexene-oxide, vinylcyclohexene monoxide (vinylcyclohexylmethoxide) And the like.

The hydrogenated aromatic hydrocarbon epoxy monomer means a compound obtained by selectively hydrogenating an aromatic epoxy monomer under a pressure in the presence of a catalyst. Aromatic epoxy monomers include, for example, bisphenol-type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl ether of bisphenol S and the like; Novolak type epoxy resins such as phenol novolak epoxy resin, cresol novolak epoxy resin, and hydroxybenzaldehyde phenol novolak epoxy resin; Glycidyl ethers of tetrahydroxyphenylmethane, glycidyl ethers of tetrahydroxybenzophenone, and epoxy polyvinylphenols, and the like.

Preferably, the epoxy-based monomer may include a cyclic aliphatic epoxy-based monomer.

The epoxy-based monomer is used in an amount of 5 to 60 parts by weight, preferably 20 to 50 parts by weight, more preferably 20 to 50 parts by weight, based on 100 parts by weight of the total of the epoxy-based silicone resin, epoxy-based monomer and (meth) By weight to 40 parts by weight. Within the above range, the coating layer can be excellent in hardness and flexibility and excellent in scratch resistance.

The epoxy-based monomer may be contained in an amount of 20 to 80 parts by weight, preferably 30 to 70 parts by weight, based on 100 parts by weight of the total of the epoxy-based silicone resin and the epoxy-based monomer. Within the above range, the coating layer can be excellent in hardness and flexibility and excellent in scratch resistance.

( Mat ) Acrylate series  Monomer

The (meth) acrylate-based monomer is a non-reactive monomer which does not react with each of the epoxy-based silicone resin and the epoxy-based monomer. (Meth) acrylate monomer does not have a functional group capable of reacting with an epoxy group, such as a hydroxyl group (non-hydroxyl group), a carboxylic acid group (non-carboxylic acid group), or an epoxy group (non-epoxy group). Through this, the (meth) acrylate-based monomer can undergo self-curing reaction, thereby enhancing the flexibility in the method of evaluating tensile strength of the present invention.

The (meth) acrylate-based monomer may include at least one of monofunctional (meth) acrylate and bifunctional (meth) acrylate. Preferably, the flexibility of the coating layer can be further improved by using monofunctional (meth) acrylate.

(Meth) acrylate having a C1 to C20 linear or branched alkyl group, a (meth) acrylate having a C3 to C20 cycloalkyl group, a (meth) acrylate having at least one heteroatom such as S, (Meth) acrylate having a C3 to C20 cycloalkyl group having 1 to 20 carbon atoms, O or N, and (meth) acrylate having an C6 to C20 aromatic group. For example, the monofunctional (meth) acrylate is at least one selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (Meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl Acrylate, cyclohexyl (meth) acrylate, boron (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate. (Meth) acrylate having a C3 to C20 cycloalkyl group, (meth) acrylate having a branched C6 to C15 alkyl group, and the like.

The bifunctional (meth) acrylate may be at least one selected from the group consisting of 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (Meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di (meth) acrylate, di Acrylate, trimethylolpropane di (meth) acrylate, (meth) acryloxyethyl isocyanurate, allyl cyclohexyl di (meth) acrylate, tricyclodecane dimethanol Acrylate, neopentyl glycol-modified trimethylpropane di (meth) acrylate, adamantane di (meth) acrylate, tricyclodecane dimethanol (meth) Dimethacrylate, 9,9-bis [4- (2-oxy-acrylic) phenyl] may include one or more of the fluorene.

The (meth) acrylate-based monomer may be contained in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the total of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate-based monomer. Within this range, the coating layer may have excellent flexibility and excellent hardness and scratch resistance.

Initiator

The initiator may include two kinds of initiators different from each other as the initiator for curing the epoxy-based silicone resin and the epoxy-based monomer, and the initiator for curing the (meth) acrylate-based monomer. The initiator may comprise a mixture of a light-ion initiator and a photo-radical initiator.

As the Gwangyang ionic initiator, any one ordinarily known to those skilled in the art can be used, and onium salts including cations and anions can be used. Specifically, the cation is at least one selected from the group consisting of diphenyl iodonium, 4-methoxydiphenyl iodonium, bis (4-methylphenyl) iodonium, bis (4-tert- butylphenyl) iodonium, bis (dodecylphenyl) Triarylsulfonium such as diaryliodonium such as [methylphenyl] [4- (2-methylpropyl) phenyl] iodonium, triphenylsulfonium and diphenyl-4-thiophenoxyphenylsulfonium, bis [4 - (diphenylsulfonio) phenyl] sulfide, and the anions include hexafluorophosphate, tetrafluoroborate, hexafluoroantimonate, hexafluoroarsenate, hexachloroantimonate, etc. . The Gwangyang ionic initiator may be included in an amount of 1 part by weight to 10 parts by weight, preferably 1 part by weight to 5 parts by weight, based on 100 parts by weight of the total amount of the epoxy siloxane resin and the epoxy monomer. Within the above range, the epoxy siloxane resin and the epoxy-based monomer can be sufficiently cured and the transparency of the remaining amount of the initiator can be prevented from being lowered.

As the photo-radical initiator, those conventionally known to those skilled in the art can be used. For example, as the photo radical initiator, a hydroxy ketone base, a phosphine oxide base, a benzoin base, an aminoketone base photo radical initiator and the like can be used. Specific examples include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenyl-phosphine oxide, benzoin, benzoin methyl ether, benzoin ethyl ether , Benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, 2,2-dimethoxy-2-phenylacetophenone, 2,2'-diethoxyacetophenone, 2,2'-dibutoxy Acetophenone, 2-hydroxy-2-methylpropiophenone, pt-butyl trichloroacetophenone, pt-butyldichloroacetophenone, 4-chloroacetophenone, 2,2'- Acetophenone compounds such as dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy- 1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1-hydroxycyclohexyl phenyl ketone, Thio) phenyl] -2-morpholino-propan-l- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-nonocydiethylaminobenzophenone, dichlorobenzophenone, 2 2-ethyl anthraquinone, 2-t-butyl anthraquinone, 2-amino anthraquinone, thioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4- Diethyl thioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethyl amino benzoic acid ester, oligo [2-hydroxy-2-methyl-1- [4- ) Phenyl] propanone] and the like. The photo radical initiator may be included in an amount of 1 part by weight to 10 parts by weight, preferably 1 part by weight to 5 parts by weight, based on 100 parts by weight of the (meth) acrylate monomer. Within this range, it is possible to prevent the (meth) acrylate-based monomer from being sufficiently cured and lowering the transparency to the remaining amount of the initiator.

The initiator may be included in an amount of 1 part by weight to 10 parts by weight, preferably 1 part by weight to 5 parts by weight, based on 100 parts by weight of the total amount of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate-based monomer. Within this range, it is possible to prevent the composition from being cured sufficiently and the transparency as a residual amount of initiator being lowered.

The composition for a window film according to this embodiment may further include nanoparticles.

Nanoparticles can further increase the hardness of the window film. The nanoparticles may include, but are not limited to, one or more of silica, aluminum oxide, zirconium oxide, and titanium oxide. The nanoparticles may be surface treated with some or all of the surface of the silicone compound for mixing with the silicone resin. Nanoparticles are not limited in shape and size. Specifically, the nanoparticles may include spherical, plate-like, amorphous, etc. particles. The nanoparticles may have an average particle diameter (D50) of 1 nm to 200 nm, specifically 10 nm to 50 nm. The hardness of the window film can be increased without affecting the surface roughness and transparency of the window film in the above range. The nanoparticles may be contained in an amount of 0.1 to 60 parts by weight, specifically 10 to 50 parts by weight per 100 parts by weight of the total of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate-based monomer. The hardness of the window film can be increased without affecting the surface roughness and transparency of the window film in the above range.

The composition for a window film according to this embodiment may further include an additive. The additive may provide additional functionality to the window film. The additive may include an additive typically added to the window film. Specifically, the additive may include, but is not limited to, at least one of a UV absorber, a reaction inhibitor, an adhesion improver, a thixotropic agent, a conductivity-imparting agent, a colorant-adjusting agent, a stabilizer, an antistatic agent and an antioxidant. The reaction inhibitor may include ethynylcyclohexane. The adhesion improver may include a silane compound having an epoxy or alkoxysilyl group. The thixotropic agent may include pyrous silica and the like. The conductivity-imparting agent may include a metal powder such as silver, copper aluminum and the like. The colorant-adjusting agent may include a pigment, a dye, and the like. The UV absorber can increase the light reliability of the window film. The UV absorbers can be conventional absorbents known to those skilled in the art. Specifically, the UV absorber may include, but is not limited to, one or more UV absorbers based on triazine, benzimidazole, benzophenone, and benzotriazole. The additive may be added in an amount of 0.01 to 5 parts by weight, specifically 0.1 to 2.5 parts by weight based on 100 parts by weight of the total of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate-based monomer. In this range, the hardness and flexibility of the window film can be improved and the additive effect can be realized.

The composition for a window film according to this embodiment may further include a solvent to facilitate coating, coating or processability. The solvent may include, but is not limited to, one or more of methyl ethyl ketone (MEK, methylethylketone), methyl isobutyl ketone, and propylene glycol monomethyl ether acetate.

Hereinafter, a flexible window film according to an embodiment of the present invention will be described with reference to FIG. 1 is a cross-sectional view of a flexible window film according to an embodiment of the present invention.

Referring to FIG. 1, the flexible window film 100 includes a base layer 110 and a coating layer 120, and the coating layer 120 may be formed of a composition for a window film according to embodiments of the present invention.

The substrate layer 110 supports the flexible window film 100 and the coating layer 120 to increase the mechanical strength of the flexible window film 100. The base layer 110 may be adhered to a display portion, a touch screen panel, or a polarizing plate by an adhesive layer or the like.

The substrate layer 110 may be formed of an optically transparent and flexible resin. For example, the resin includes a polyester resin including a polyethylene terephthalate, a polyethylene naphthalate, a polybutylene terephthalate, a polybutylene naphthalate, etc., a polycarbonate resin, a polyimide resin, a polystyrene resin, polymethylmethacrylate A poly (meth) acrylate resin, a cycloolefin polymer resin, and a polyamide resin. The resin may be contained in the base layer 110 alone or in combination.

The base layer 110 may have a thickness of 10 占 퐉 to 200 占 퐉, specifically, 20 占 퐉 to 150 占 퐉, more specifically, 50 占 퐉 to 100 占 퐉. Can be used in the flexible window film in the above range.

The coating layer 120 is formed on the base layer 110 to protect the base layer 110, the display portion, the touch screen panel or the polarizing plate, improve the appearance, have high flexibility and high hardness and can be used in a flexible display device can do. The coating layer 120 may have a thickness of 5 占 퐉 to 100 占 퐉, specifically 10 占 퐉 to 80 占 퐉, more specifically 10 占 퐉 to 50 占 퐉. Can be used in the flexible window film in the above range.

Although not shown in FIG. 1, a functional surface layer such as an antireflection layer, an antiglare layer, a hard coat layer, a translucent layer, and an antiglare layer may be further formed on the other surface of the coating layer 120 to provide additional functions to the flexible window film . 1, a coating layer 120 may be further formed on the other surface of the substrate layer 110. [

The flexible window film 100 may have a light transmittance of 88% or more and specifically 88% to 100% in a visible light region specifically at a wavelength of 400 nm to 800 nm. It can be used as a flexible window film in the above range.

A flexible window film 100 may indentation hardness can be 45mN / mm ^2, greater than specifically 45mN / mm ² exceeding 100mN / mm ² or less. Within this range, the hardness is good and can be used as a window film.

Flexible window films may have a flexibility of 2.5% or more, preferably 2.5% to 5.0%, when evaluating the flexibility by tensile strength. In the above range, since the flexibility is excellent, cracking may not occur even when the window film is folded out-folding.

The flexible window film 100 was placed on a window coating layer with a tip equipped with a steel wool (for example, Liberon Steel wool # 0000), and then placed on the window coating layer surface with a load of 1.5 kg, a speed of 60 mm / The number of scratches that occurred when moved could be less than 5. In the above range, scratch resistance is good and appearance can be good.

The flexible window film 100 may have a thickness of 5 占 퐉 to 300 占 퐉. It can be used as a flexible window film in the above range.

Hereinafter, a flexible window film according to another embodiment of the present invention will be described with reference to FIG. 2 is a cross-sectional view of a flexible window film according to another embodiment of the present invention.

2, the flexible window film 200 includes an adhesive layer 130 formed on the other surface of the base layer 110 such that the adhesive layer 130, the base layer 110, and the window coating layer 120 are sequentially The flexible window film 100 is substantially the same as the flexible window film 100 except that the flexible window film 100 is laminated. The adhesive layer 130 is further formed on the other surface of the base layer 110, so that adhesion between the flexible window film and the touch screen panel, the polarizing plate, or the display portion can be facilitated. Is substantially the same as the flexible window film according to an embodiment of the present invention, except that an adhesive layer is further formed. Hereinafter, only the adhesive layer 130 will be described.

The adhesive layer 130 adheres to a polarizing plate, a touch screen panel, or a display unit that can be disposed under the flexible window film 200, and may be formed of a composition for a pressure-sensitive adhesive layer.

In one embodiment, the adhesive layer 130 may be formed of a composition for a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive resin such as a (meth) acrylic resin, a urethane resin, a silicone resin, and an epoxy resin, a curing agent, a photoinitiator and a silane coupling agent.

The (meth) acrylic resin is a (meth) acrylic copolymer having an alkyl group, a hydroxyl group, an aromatic group, a carboxylic acid group, an alicyclic group, a heteroalicyclic group, or the like and may include a conventional (meth) acrylic copolymer. Specifically, a (meth) acrylic monomer having an unsubstituted C1 to C10 alkyl group, a (meth) acrylic monomer having a C1 to C10 alkyl group having at least one hydroxyl group, a (meth) acrylic monomer having an C6 to C20 aromatic group (Meth) acrylic monomer having a carboxylic acid group, a (meth) acrylic monomer having a C3 to C20 alicyclic group, a C3 to C10 heteroalicyclic group having at least one of nitrogen (N), oxygen (O) (Meth) acryl-based monomer having at least one group selected from the group consisting of (meth) acryl-based monomers.

The curing agent may be a bifunctional (meth) acrylate such as hexanediol diacrylate as a polyfunctional (meth) acrylate; Trifunctional (meth) acrylates of trimethylolpropane tri (meth) acrylate; Tetrafunctional (meth) acrylates such as pentaerythritol tetra (meth) acrylate; Pentafunctional (meth) acrylates such as dipentaerythritol penta (meth) acrylate; (Meth) acrylate such as dipentaerythritol hexa (meth) acrylate, but are not limited thereto.

The photoinitiator may include the above-described photoinitiator as a conventional photoinitiator.

The silane coupling agent may include a silane coupling agent having an acryl group such as 3-acryloxypropyltrimethoxysilane and the like.

The composition for the adhesive layer may comprise 100 parts by weight of a (meth) acrylic resin, 0.1 to 30 parts by weight of a curing agent, 0.1 to 10 parts by weight of a photoinitiator, and 0.1 to 20 parts by weight of a silane coupling agent. Within this range, the flexible window film can be adhered well onto the display portion, the touch screen panel or the polarizing plate.

In another embodiment, the adhesive layer 130 may be the adhesive layer 110c described below.

The thickness of the adhesive layer 130 may be 10 占 퐉 to 100 占 퐉. In the above range, the optical element such as the flexible window film and the polarizing plate can be sufficiently adhered.

Hereinafter, a window film according to another embodiment of the present invention will be described with reference to FIG. 3 is a cross-sectional view of a window film according to another embodiment of the present invention.

3, the flexible window film 150 includes a base layer 110A instead of the base layer 110, except that the base layer 110A and the window coating layer 120 are sequentially laminated Is substantially the same as the flexible window film (100).

The base layer 110A includes a first film 110a, a second film 110b and an adhesive layer 110c formed between the first film 110a and the second film 110b. By including the base layer 110A, the flexible window film can have an effect of improving the flexibility and further improving the impact resistance as compared to the window film including the base layer 100. [

The first film 110a and the second film 110b may support the flexible window film 150, respectively. The first film 110a and the second film 110b may be formed of the optically transparent and flexible resin, respectively. The first film 110a and the second film 110b may be formed of the same or different resins. For example, the first film 110a and the second film 110b may be formed of at least one of a polyester resin, a polycarbonate resin, a polyimide resin, a poly (meth) acrylate resin, and a cyclic olefin polymer resin, respectively Film.

The first film 110a and the second film 110b may have different thicknesses or the same thickness. Each of the first film 110a and the second film 110b may have a thickness of 10 mu m to 100 mu m, preferably 30 mu m to 50 mu m. Within the above range, there can be obtained an effect of excellent flexibility and impact resistance.

The base layer 110A may have a thickness of 10 mu m to 275 mu m, specifically 20 mu m to 200 mu m, more specifically 50 mu m to 110 mu m. Can be used in the flexible window film in the above range.

3 shows a case where the coating layer 120 is directly formed on the second film 110b. In the case where the coating layer 120 is formed directly on the first film 110a, that is, when the second film 110b, 110c, the first film 110a, and the coating layer 120 may be sequentially formed.

The adhesive layer 110c may be formed between the first film 110a and the second film 110b to adhere them to each other. The adhesive layer 110c can improve the bending reliability at the time of repeated folding of the window film and can increase the impact strength of the window film.

The thickness of the adhesive layer 110c may be 10 占 퐉 to 75 占 퐉. Within the above range, there can be obtained an effect of excellent flexibility and impact resistance. Preferably, the thickness of the adhesive layer 110c may be 10 占 퐉 to 50 占 퐉 and 10 占 퐉 to 30 占 퐉.

The adhesive layer 110c may have a haze of 5% or less, specifically 3% or less, more specifically 1% or less, in the visible light region at a thickness of 100 占 퐉. In the above-mentioned range, when the adhesive layer is used in an optical display device, it exhibits excellent transparency.

The adhesive layer 110c may be formed of a transparent clear adhesive (OCA). The adhesive layer 110c is a monomer mixture for a (meth) acrylic copolymer having a hydroxyl group; Initiator; And a composition for a pressure-sensitive adhesive layer containing at least one of macromonomer and organic nanoparticles. The monomer mixture may be contained in the pressure-sensitive adhesive composition in the state of a monomer mixture in which polymerization is not carried out at all, but the monomer mixture may be contained as a partially polymerized partial polymer. Preferably, the composition for a pressure-sensitive adhesive layer comprises a monomer mixture for a (meth) acrylic copolymer having a hydroxyl group; Initiator; And organic nanoparticles.

The monomer mixture may be composed of a hydroxyl group-containing (meth) acrylate and an alkyl group-containing (meth) acrylate.

The hydroxyl group-containing (meth) acrylate can provide the adhesion of the adhesive layer. The hydroxyl group-containing (meth) acrylate may be a (meth) acrylate containing at least one hydroxyl group. For example, the hydroxyl group-containing (meth) acrylate may be at least one selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, (Meth) acrylate, diethylene glycol mono (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (Meth) acrylate, trimethylolethane di (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4- Hydroxycyclopentyl (meth) acrylate (Meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, and the like. The hydroxyl group-containing (meth) acrylate is used in an amount of 5 wt% to 40 wt%, such as 8 wt% to 30 wt%, 10 wt% to 30 wt% of the total of the hydroxyl group-containing (meth) acrylate and alkyl group- % &Lt; / RTI &gt; by weight. The adhesive strength and endurance reliability of the adhesive layer in the above range can be further improved.

The alkyl group-containing (meth) acrylate may become a copolymer to form a matrix of an adhesive layer. The alkyl group-containing (meth) acrylate may include an unsubstituted linear or branched alkyl (meth) acrylate having 1 to 20 carbon atoms. (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, (Meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, ethylhexyl (meth) acrylate, octyl (Meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, and isobonyl (meth) acrylate. The alkyl group-containing (meth) acrylate is used in an amount of 60 to 95% by weight, such as 65 to 92% by weight, 68 to 90% by weight, based on the total of the hydroxyl group-containing (meth) acrylate and alkyl group- By weight, and 70% by weight to 90% by weight. The adhesive strength and endurance reliability of the adhesive layer in the above range can be further improved.

The monomer mixture may further comprise copolymerizable monomers. The copolymerizable monomer may be contained in the (meth) acrylic copolymer to provide additional effects to the (meth) acrylic copolymer, the pressure sensitive adhesive composition or the pressure sensitive adhesive layer. The copolymerizable monomer is a monomer having an ethylene oxide, a monomer having propylene oxide, a monomer having an amine group, a monomer having an alkoxy group, a monomer having a phosphoric acid group, or a monomer having an alkyl group (meth) , A monomer having a sulfonic acid group, a monomer having a phenyl group, a monomer having a silane group, a monomer having a carboxylic acid group, and an amide group-containing (meth) acrylate.

The copolymerizable monomer is contained in an amount of not more than 15 parts by weight, specifically not more than 10 parts by weight, more specifically 0.05 to 8 parts by weight, based on 100 parts by weight of the sum of the hydroxyl group-containing (meth) acrylate and alkyl group-containing (meth) . In the above range, the pressure-sensitive adhesive composition can further improve the adhesive force and the recoverability of the pressure-sensitive adhesive film.

Initiators can be used to cure (partially polymerize) the monomer mixture into a (meth) acrylic copolymer or to cure a viscous liquid into a film. The initiator may include at least one of a photopolymerization initiator and a thermal polymerization initiator. The photopolymerization initiator may include the above-mentioned photopolymerization initiator. The thermal polymerization initiator is not particularly limited as long as it has the above-mentioned physical properties, and ordinary initiators can be used. The initiator is used in an amount of 0.0001 to 5 parts by weight, specifically 0.001 to 3 parts by weight per 100 parts by weight of the sum of the hydroxyl group-containing (meth) acrylate and alkyl group-containing (meth) acrylate constituting the (meth) . In the above range, the curing reaction can be completely carried out, and the remaining amount of the initiator remains, the permeability can be prevented from being lowered, the bubble generation can be lowered, and the reactivity can be improved.

The macromonomer may have a functional group curable by an active energy ray and may be polymerized with a hydroxyl group-containing (meth) acrylate and an alkyl group-containing (meth) acrylate. Specifically, the macromonomer can be represented by the following formula (2): &lt; EMI ID =

(2)

(In the formula 2, R ₁ is hydrogen or a methyl group, X represents a single bond or a divalent coupler, Y is methyl (meth) acrylate, ethyl (meth) acrylate, n- butyl (meth) acrylate, iso- butyl (Meth) acrylate, t-butyl (meth) acrylate, styrene, and (meth) acrylonitrile.

The macromonomer may have a number average molecular weight of 2,000 to 20,000, specifically 2,000 to 10,000, more specifically 4,000 to 8,000. Within the above range, sufficient adhesive strength can be obtained, heat resistance is excellent, and deterioration of workability due to an increase in viscosity of the pressure-sensitive adhesive composition can be suppressed. The macromonomer may have a glass transition temperature of from 40 캜 to 150 캜, specifically from 60 캜 to 140 캜, more specifically from 80 캜 to 130 캜. In this range, the pressure-sensitive adhesive layer can exhibit a sufficient cohesive force, and can suppress the degree of stickiness and deterioration of the adhesive force.

2 the coupler is an arylene group, -NR a C1 to C10 alkyl groups, C7 to C13 aryl alkyl group, C6 to C12 ² - (wherein, R ² is an alkyl group of hydrogen, or a C1 to C5), COO-, - _{O-, -S-, -SO 2 NH-,} -NHSO 2 -, may be a group derived from -NHCOO-, -OCONH, or heterocyclic.

The divalent linking group may be represented by the following general formulas (2a) to (2d):

&Lt; EMI ID =

(2b)

(2c)

(2d)

(In the above Chemical Formulas (2a) to (2d), * denotes the connecting site of the element)

Commercial macromonomers may be used. For example, a macromonomer wherein the terminal is methacryloyl group and the segment corresponding to Y is methyl methacrylate, the segment corresponding to Y is styrene, the segment corresponding to Y is a styrene / acryl Macromonomers in which the segment corresponding to Y is butyl acrylate, and the like can be used.

The macromonomer is used in an amount of 20 parts by weight or less, specifically 0.1 part by weight to 20 parts by weight, 0.1 part by weight to 10 parts by weight, 0.5 part by weight (meth) acrylate based on 100 parts by weight of the sum of the hydroxyl group-containing (meth) To 5 parts by weight. Within the above range, the viscoelasticity of the adhesive layer can be balanced with the modulus and the restoring force, and the increase in haze of the adhesive layer can be prevented.

The average particle diameter of the organic nanoparticles may be 10 nm to 400 nm, specifically 10 nm to 300 nm, more specifically 30 nm to 280 nm, more specifically 50 nm to 280 nm. In the above range, the transparency of the adhesive layer may be good with the total light transmittance of not less than 90% in the visible light region without affecting the folding of the adhesive layer.

The refractive index difference between the organic nanoparticles and the (meth) acrylic copolymer having a hydroxyl group may be 0.1 or less, specifically 0 or more and 0.05 or less, specifically 0 or more and 0.02 or less. In the above range, the transparency of the adhesive layer can be excellent. The refractive index of the organic nanoparticles may be 1.35 to 1.70, specifically 1.40 to 1.60. Within this range, the transparency of the adhesive layer may be excellent.

The organic nanoparticles may include, but are not limited to, core-shell type and simple nanoparticles such as a bead type. In the case of a core-shell type, the core and the shell may satisfy the following formula 1: that is, both the core and the shell may be nanoparticles that are organic materials. When the above-mentioned particle form is used, the adhesive property of the adhesive layer is good, and the balance property of elasticity and flexibility can be effective.

<Formula 1>

Tg (c) < Tg (s)

(Unit: 占 폚), and Tg (s) is the glass transition temperature (unit: 占 폚) of the shell.

As used herein, the term " shell " means the outermost layer of the organic nanoparticles. The core may be a single spherical particle. However, the core may further comprise additional layers surrounding the spherical particles if they have the above glass transition temperature.

Specifically, the glass transition temperature of the core may be -150 ° C to 10 ° C, specifically -150 ° C to -5 ° C, more specifically -150 ° C to -20 ° C. Within this range, there may be a low temperature and / or room temperature viscoelastic effect of the adhesive layer. The core may contain at least one of polyalkyl (meth) acrylate, polysiloxane or polybutadiene having the above glass transition temperature.

The polyalkyl (meth) acrylate may be at least one selected from the group consisting of polymethyl acrylate, polyethylacrylate, polypropyl acrylate, polybutyl acrylate, polyisopropyl acrylate, polyhexyl acrylate, polyhexyl methacrylate, polyethylhexyl acrylate And polyethylhexyl methacrylate, polysiloxane, and is not necessarily limited thereto.

The polysiloxane can be, for example, an organosiloxane (co) polymer. The organosiloxane (co) polymer may be one which is not cross-linked, or a cross-linked (co) polymer may be used. In order to impart impact resistance and colorability, an organosiloxane (co) polymer in a crosslinked state can be used. It is a crosslinked form of organosiloxane, specifically crosslinked dimethylsiloxane, methylphenylsiloxane, diphenylsiloxane or a mixture of two or more thereof. By using a copolymerized form of two or more organosiloxanes, the refractive index can be adjusted from 1.41 to 1.50.

The crosslinking state of the organosiloxane (co) polymer can be determined by the degree of dissolution by various organic solvents. As the crosslinking state deepens, the degree of dissolution by the solvent becomes smaller. As the solvent for determining the crosslinking state, acetone, toluene and the like can be used. Specifically, the organosiloxane (co) polymer may have a portion which is not dissolved by acetone or toluene. The insoluble matter to the toluene of the organosiloxane copolymer may be 30% or more.

Additionally, the organosiloxane (co) polymer may further comprise an alkyl acrylate crosspolymer. The alkyl acrylate crosslinked polymer may be selected from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. For example, n-butyl acrylate or 2-ethylhexyl acrylate having a low glass transition temperature may be used.

Specifically, the glass transition temperature of the shell may be from 15 캜 to 150 캜, specifically from 35 캜 to 150 캜, more specifically from 50 캜 to 140 캜. In the above range, the dispersibility of the organic nanoparticles in the (meth) acrylic copolymer may be excellent. The shell may comprise a polyalkyl methacrylate having said glass transition temperature. For example, it is possible to use polymethylmethacrylate (PMMA), polyethylmethacrylate, polypropylmethacrylate, polybutylmethacrylate, polyisopropylmethacrylate, polyisobutylmethacrylate and polycyclohexylmethacrylate Rate, &lt; / RTI &gt; but is not necessarily limited thereto.

The core may comprise from 30 wt% to 99 wt%, specifically from 40 wt% to 95 wt%, and more specifically from 50 wt% to 90 wt%, of the organic nanoparticles. Within the above range, the folding property of the adhesive layer may be good in a wide temperature range. The shell may comprise from 1 wt% to 70 wt%, specifically from 5 wt% to 60 wt%, more specifically from 10 wt% to 50 wt%, of the organic nanoparticles. Within the above range, the folding property of the adhesive layer may be good in a wide temperature range.

The organic nanoparticles are added in an amount of 0.1 part by weight to 20 parts by weight, specifically 0.5 part by weight to 10 parts by weight, specifically 0.5 part by weight to 100 parts by weight, based on 100 parts by weight of the sum of the hydroxyl group-containing (meth) acrylate and alkyl group- 8 parts by weight. Within the above range, the modulus of the pressure-sensitive adhesive layer at high temperature can be increased, the folding property of the pressure-sensitive adhesive layer at room temperature and high temperature can be improved, and the low temperature and / or room temperature viscoelasticity of the pressure-

The organic nanoparticles can be prepared by conventional emulsion polymerization, suspension polymerization, or solution polymerization.

The adhesive layer composition may further comprise a silane coupling agent. The composition for a pressure-sensitive adhesive layer may further comprise a crosslinking agent. The crosslinking agent can increase the degree of crosslinking of the composition for a pressure-sensitive adhesive layer to increase the mechanical strength of the pressure-sensitive adhesive layer. The crosslinking agent may be a bifunctional (meth) acrylate such as a polyfunctional (meth) acrylate capable of being cured with an active energy ray, such as hexanediol diacrylate, or a trifunctional to hexafunctional (meth) acrylate .

3 shows a case where the base film is a film laminate in which the first film 110a and the second film 110b are laminated by the adhesive layer 110c. However, the case where the base layer includes three or more films and at least two or more of them are laminated with each other by the adhesive layer 110c can be included in the scope of the present invention.

Hereinafter, a flexible display device according to an embodiment of the present invention will be described with reference to FIG. 4 is a cross-sectional view of a flexible display device according to an embodiment of the present invention.

4, the flexible display device 300 includes a display portion 350a, an adhesive layer 360, a polarizing plate 370, a touch screen panel 380, and a flexible window film 390, (390) may comprise a flexible window film according to embodiments of the present invention.

The display unit 350a is for driving the flexible display device 300 and may include an optical element including an OLED, an LED, or an LCD device formed on a substrate and a substrate. The display portion 350a may include a conventional structure known to those skilled in the art, and may include a lower substrate, a thin film transistor, an organic light emitting diode, a planarization layer, a protection layer, and an insulation layer.

The lower substrate supports the display portion, and a thin film transistor and an organic light emitting diode may be formed on the lower substrate. A flexible printed circuit board for driving the touch screen panel may be formed on the lower substrate. The flexible printed circuit board may further include a timing controller for driving the organic light emitting diode array, a power supply unit, and the like. The lower substrate may include a substrate formed of a flexible resin. Specifically, the lower substrate may include a flexible substrate such as a silicon substrate, a polyimide substrate, a polycarbonate substrate, and a polyacrylate substrate, but is not limited thereto.

A plurality of pixel regions are defined by a plurality of driving wirings (not shown) and sensor wirings (not shown) crossing the display region of the lower substrate, and an organic light emitting diode connected to the thin film transistors and the thin film transistors is included in each pixel region An organic light emitting diode array may be formed. In a non-display area of the lower substrate, a gate driver for applying an electrical signal to the driving wiring may be formed in the form of a gate in panel. The gate-in panel circuit portion may be formed on one side or both sides of the display region.

The thin film transistor can be formed on the lower substrate by controlling the electric current flowing in the semiconductor by applying an electric field perpendicular thereto. The thin film transistor may include a gate electrode, a gate insulating film, a semiconductor layer, a source electrode, and a drain electrode. The thin film transistor includes an oxide thin film transistor using an oxide such as indium gallium zinc oxide (IGZO), ZnO, or TiO.sub.2 as a semiconductor layer, an organic thin film transistor using an organic material as a semiconductor layer, an amorphous silicon thin film transistor using amorphous silicon as a semiconductor layer, Or a polycrystalline silicon thin film transistor using polycrystalline silicon as a semiconductor layer.

The planarization layer may be formed by flattening the top surface of the thin film transistor and the circuit part by covering the thin film transistor and the circuit part, thereby forming the organic light emitting diode. The planarization layer may be formed of a spin-on-glass (SOG) film, a polyimide-based polymer, a polyacrylic polymer, or the like, but is not limited thereto.

The organic light emitting diode emits light by self-emission, and may include a first electrode, an organic light emitting layer, and a second electrode sequentially stacked. The adjacent organic light emitting diodes can be separated by an insulating film. The organic light emitting diode may include a bottom emission structure in which light generated in the organic emission layer is emitted through the bottom substrate, or a top emission structure in which light generated in the organic emission layer is emitted upward.

The protective film may cover the organic light emitting diode to protect the organic light emitting diode. The protective film may be formed of an inorganic material such as SiOx, SiNx, SiC, SiON, SiONC and aC (amorphous carbon) and an organic material such as (meth) acrylate, And the like. Specifically, the protective film may include an encapsulation layer in which a layer formed of an inorganic material and a layer formed of an organic material are sequentially stacked one or more times.

Referring again to FIG. 4, the adhesive layer 360 is formed of a pressure-sensitive adhesive composition comprising a (meth) acrylate resin, a curing agent, an initiator and a silane coupling agent to adhere the display portion 350a and the polarizing plate 370 .

The polarizing plate 370 can implement polarizing of the inner light or prevent reflection of the external light to realize the display or to increase the contrast ratio of the display. The polarizing plate may be composed of a polarizer alone. Or the polarizing plate may include a polarizing film and a protective film formed on one or both sides of the polarizing film. Or the polarizing plate may include a polarizer and a protective coating layer formed on one or both sides of the polarizer. The polarizer, the protective film, and the protective coating layer may be conventional ones known to those skilled in the art.

The touch screen panel 380 senses a change in capacitance generated when a conductor such as a human body or a stylus touches, and generates an electrical signal. The display unit 350a can be driven by this signal. The touch screen panel 380 is formed by patterning a flexible conductive conductive material. The touch screen panel 380 may include a first sensor electrode and a second sensor electrode formed between the first sensor electrode and the first sensor electrode. have. The conductor for the touch screen panel 380 may include, but is not limited to, metal nanowires, conductive polymers, carbon nanotubes, and the like.

The flexible window film 390 may be formed at the outermost portion of the flexible display device 300 to protect the display device.

Although not shown in FIG. 4, an adhesive layer is further formed between the polarizer 370 and the touch screen panel 380 and / or between the touch screen panel 380 and the flexible window film 390 to form a polarizing plate, a touch screen panel, It is possible to strengthen the bonding between the window films. The pressure-sensitive adhesive layer may be formed of a pressure-sensitive adhesive composition comprising a (meth) acrylate resin, a curing agent, an initiator, and a silane coupling agent. Or the adhesive layer may be an adhesive layer containing the organic nanoparticles. Although not shown in FIG. 6, a polarizing plate is further provided under the display unit 350a, so that polarized light can be realized.

Hereinafter, a flexible display device according to another embodiment of the present invention will be described with reference to FIG. 5 is a cross-sectional view of a flexible display device according to another embodiment of the present invention.

5, the flexible display device 400 includes a display portion 350a, a touch screen panel 380, a polarizing plate 370, and a flexible window film 390, and the flexible window film 390 includes the present invention May include a flexible window film according to embodiments of the invention. Except that the touch screen panel 380 is not directly formed on the flexible window film 390 but the touch screen panel 380 is formed below the polarizer 370. In this case, Device. At this time, the touch screen panel 380 may be formed together with the display portion 350a. In this case, since the touch screen panel 380 is formed on the display unit 350a together with the display unit 350a, the thickness of the touch screen panel 380 can be thinner and brighter than that of the flexible display device according to an embodiment of the present invention. In this case, the touch screen panel 380 can be formed by deposition or the like, but is not limited thereto. Although not shown in FIG. 5, a gap between the display portion 350a and the touch screen panel 380 and / or between the touch screen panel 380 and the polarizer 370 and / or between the polarizer 370 and the flexible window film 390 An adhesive layer is further formed, thereby increasing the mechanical strength of the display device. The pressure-sensitive adhesive layer may be formed of a pressure-sensitive adhesive composition comprising a (meth) acrylate resin, a curing agent, an initiator, and a silane coupling agent. Or the adhesive layer may be an adhesive layer containing the organic nanoparticles. Although not shown in FIG. 5, a polarizing plate is further provided under the display unit 350a to thereby guide polarized light to improve the display image.

Hereinafter, a flexible display device according to another embodiment of the present invention will be described with reference to FIG. 6 is a cross-sectional view of a flexible display device according to another embodiment of the present invention.

6, the flexible display device 500 includes a display portion 350b, an adhesive layer 360, and a flexible window film 390, and the flexible window film 390 includes a flexible window film 390 according to embodiments of the present invention. And may include a flexible window film. Is substantially the same as the flexible display device according to an embodiment of the present invention, except that only the display portion 350b is capable of driving the device and the polarizing plate and the touch screen panel are excluded.

The display portion 350b may include an LCD, an OLED, or an optical element including an LED element formed on the substrate, and the display portion 350b may have a touch screen panel formed therein.

Hereinafter, a method of manufacturing a window film according to an embodiment of the present invention will be described.

The flexible window film 100 can be manufactured by a method of manufacturing a flexible window film including coating and curing a composition for a window film according to embodiments of the present invention on a substrate layer 110. [

The method for coating the composition for a window film on a base layer may be, but not limited to, bar coating, spin coating, dip coating, roll coating, flow coating, die coating and the like. A composition for a window film may be coated on the base layer to a thickness of 5 to 100 탆. It is possible to secure a desired coating layer within the above range, and to have an excellent hardness and flexibility. Curing is the curing of the composition for the window film to form a coating layer, which may include photo-curing. Photocuring may involve irradiation with light amount of 10 mJ / cm ² to 1,000mJ / cm ² at a wavelength of 400nm or less. Within this range, the composition for a window film can be sufficiently cured. As described above, the composition for a window film of the present invention can produce a window film having sufficient hardness by photocuring only after photocuring and without additional heat treatment or aging, thereby improving the processability. The method may further comprise drying the composition for the window film before coating the composition for the window film on the substrate layer and then curing the composition. By drying and curing, it is possible to prevent the surface roughness of the coating layer from becoming high due to long-time photocuring. The drying may be performed at 40 캜 to 200 캜 for 1 minute to 30 hours, but is not limited thereto.

Hereinafter, the present invention will be described in more detail by way of examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Manufacturing example : Epoxy-based silicone resin

85 mol% of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (KBM-303, Shinrytsu) and 15 mol% of (3-glycidoxypropyl) trimethoxysilane (KBM- Was placed in a 1 L 3-neck flask. It was added to the silicone monomer mixture compared to 0.1mol% of KOH and 1 equivalent of the total silicon monomer compared to water, and stirred at 65 ℃ for 8 hours, followed by washing with water and concentrated with _{toluene, (EcSiO 3/2) 0.85} (GpSiO 3 _{/ 2} ) _{0 . 15} epoxy-based silicone resin (weight average molecular weight by gel permeation chromatography (GPC): 5,500 g / mol).

Specific specifications of the components used in the following examples and comparative examples are as follows.

(A) Silicone resin: Epoxy-based silicone resin

(B) Epoxy-based monomer: Celloxide 2021P, Sartomer Co.

(C1) SR506, Sartomer (monofunctional acrylate, isobornyl acrylate), (C2) SR440, Sartomer (monofunctional acrylate, isooctyl acrylate)

(D) Initiator: (D1) IK-1 (Sanapro), (D2) Irgacure 184 (Ciba)

Example  One

Epoxy silicone resin, epoxy-based monomer, (meth) acrylate-based monomer, and initiator in the amounts shown in Table 1 were mixed with a solvent methyl ethyl ketone in an amount of 60 parts by weight, respectively, to prepare a composition for a coating layer . The prepared composition for a coating layer was coated on a polyimide film (PI film, Samsung SDI, thickness: 80 탆), dried at 100 캜 for 4 minutes, irradiated with UV at 500 mJ / cm ² under a nitrogen atmosphere, A window film having a coating layer of 10 mu m was prepared.

Example  2 to Example  4

A window film was prepared in the same manner as in Example 1, except that the epoxy-based silicone resin, the epoxy-based monomer, the (meth) acrylate-based monomer and the initiator were changed in kind and / or content as shown in Table 1 below.

Comparative Example  1 to Comparative Example  3

A window film was prepared in the same manner as in Example 1, except that the epoxy-based silicone resin, the epoxy-based monomer, the (meth) acrylate-based monomer and the initiator were changed in kind and / or content as shown in Table 1 below.

The following properties of the window films prepared in Examples and Comparative Examples were measured and are shown in Table 1 below.

(1) Indentation hardness: The window film is placed at the top of the window coating layer on a soda lime glass plate of 2T thickness at 25 ° C. The window coating layer was pressed with a constant force of 30 mN under a load of 15 seconds, creeped for 5 seconds, relaxed for 20 seconds, and indentation hardness was measured with micro indentor (Vicker particle) in the form of a straight diamond pyramid having a square base. Indentation hardness was measured using HM2000LT Micro Indentor (Fisher). 5 times and the average value was obtained. Can be used as window film when indentation hardness exceeds 45mN / mm ² .

(2) Scuff test (Scratch resistance test): A tip (diameter: 20 mm) equipped with a steel wool (Ribenon # 0000) was placed on a window coating layer of a window film using a scuff tester, A speed of 60 mm / sec, and a moving distance of 40 mm. Record the number of scratches that occurred after repeating this 10 times. The lower the number, the better the scratch resistance. If the number is less than 5, it can be used as window film.

(3) Crack strain: The tensile strength was evaluated using a universal testing system (UTM). The window film was cut into a rectangle having a width of x 10 mm x 100 mm to prepare a specimen. The tensile strength of the specimen was measured when the specimen was pulled from both sides at a tensile speed of 10 mm / min and cracks were generated in the coating layer. Can be used as window film when crack strain is 2.5% or more.

Example Comparative Example One 2 3 4 One 2 3 (A) 59.7 48 59.7 48 60 59.9 45 (B) 39.8 32 39.8 32 40 40 30 (C1) 0.5 20 - - - 0.1 25 (C2) - - 0.5 20 - - - (D1) 2 2 2 2 2 2 2 (D2) 2 2 2 2 - 2 2 Indentation
Hardness (mN / mm ² ) 59 51 57 49 61.0 60 45 Scuff test () 0 3 One 5 0 0 10 Crack Strain (%) 2.5 3.3 2.8 3.5 1.8 2.0 4.0

As shown in Table 1, the composition for a window film of the present invention has excellent softness due to an indentation hardness of more than 45 mN / mm &lt; ² &gt; and a crack strain of 2.5% Respectively.

On the other hand, Comparative Example 2, Comparative Example 3, and Comparative Example 1, which did not contain the (meth) acrylate monomer of the present invention, showed improvement in flexibility, indentation hardness and scratch resistance of the present invention I could not get it all.

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 (16)

An epoxy resin composition comprising an epoxy-based silicone resin, an epoxy-based monomer, a (meth) acrylate-based monomer and an initiator,
&Lt; Formula 1 >
(R ¹ SiO _3/2 ) _x (R ² SiO _3/2 ) _y (R ³ R ⁴ SiO _2/2 ) _z (SiO _4/2 ) _w
(Wherein R ¹ represents an alicyclic epoxy group-containing functional group,
R ² is a glycidyl group-containing functional group,
R ³ and R ⁴ are each independently hydrogen, an alicyclic epoxy group-containing functional group, a glycidyl group-containing functional group, an unsubstituted or substituted C 1 to C 20 alkyl group, an unsubstituted or substituted C 5 to C 20 cycloalkyl group, A substituted C6 to C20 aryl group,
0 &lt; y < 1, 0 < z &
The (meth) acrylate-based monomer is non-reactive with respect to the epoxy-based silicone resin and the epoxy-based monomer,
Based on 100 parts by weight of the sum of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate-based monomer, the sum of the epoxy-based silicone resin and the epoxy-based monomer: the weight ratio of the (meth) Is from 80:20 to 99.5: 0.5.
The composition for a window film according to claim 1, wherein the epoxy-based silicone resin is represented by the following formula (1-1):
&Lt; Formula 1-1 >
(R ¹ SiO _3/2 ) _x (R ² SiO _3/2 ) _y
(Wherein R ¹ is an alicyclic epoxy group-containing functional group,
R ² is a glycidyl group-containing functional group,
0.5? X <1, 0 <y? 0.5, x + y = 1).
The composition for a window film according to claim 2, wherein 0.85? X? 0.99 and 0.01? Y? 0.15.
The composition according to claim 1, wherein the (meth) acrylate-based monomer comprises at least one of (meth) acrylate having a C3 to C20 cycloalkyl group, (meth) acrylate having a branched C6 to C15 alkyl group &Lt; / RTI &gt;
The composition for a window film according to claim 1, wherein the (meth) acrylate-based monomer comprises at least one of isobornyl (meth) acrylate and isooctyl (meth) acrylate.
The composition for a window film according to claim 1, wherein the epoxy-based monomer comprises a cyclic aliphatic epoxy-based monomer.
The epoxy resin composition according to claim 1, wherein the epoxy-based silicone resin is contained in an amount of 20 to 90 parts by weight in 100 parts by weight of the total of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate- Composition for film.
The epoxy resin composition according to claim 1, wherein the epoxy-based monomer is contained in an amount of 5 to 60 parts by weight based on 100 parts by weight of the total of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate- / RTI &gt;
The composition according to claim 1, wherein the (meth) acrylate monomer is contained in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the total of the epoxy-based silicone resin, the epoxy-based monomer and the (meth) acrylate- By weight based on the total weight of the composition.
2. The composition of claim 1, wherein the initiator comprises a mixture of a photo radical initiator and a photoion initiator.
Wherein the flexible window film has an indentation hardness of more than 45 mN / mm &lt; ² &gt; and a crack strain of 2.5% or more.
The flexible window film according to claim 11, wherein the coating layer is formed from the composition for a window film according to any one of claims 1 to 10.
12. The method of claim 11, wherein the substrate layer comprises a film laminate,
Wherein the film laminate is a laminate of two or more films laminated by an adhesive layer.
The flexible window film of claim 11, wherein the film laminate is a laminate of a first film, a second film, and the first film and the second film by the adhesive layer.
15. The method of claim 14, wherein the adhesive layer comprises a monomer mixture for a (meth) acrylic copolymer having a hydroxyl group; Initiator; And a composition for a pressure-sensitive adhesive layer comprising at least one of a macromonomer and an organic nanoparticle.
An optical display device comprising the flexible window film of claim 11.

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