KR102374305B1 - Composition for window film, flexible window film prepared using the same and flexible display apparatus comprising the same - Google Patents

Abstract

A composition for a window film comprising the siloxane resin of Formula 1, a crosslinking agent, and an initiator, a flexible window film formed therefrom, and a flexible display device including the same are provided.

Description

Composition for a window film, a flexible window film formed therefrom, and a flexible display device comprising the same

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

Recently, while replacing a glass substrate or a high hardness substrate with a film in a display device, a flexible display device having the flexibility to be folded and unfolded has been developed. Flexible display devices are thin, light, and resistant to shock, and can be folded and unfolded, so they can be manufactured in various shapes.

In the flexible display device, not only the substrate but also various elements included in the device must have flexibility. Since the window film is located at the outermost part of the display device, it must have excellent hardness and flexibility. In particular, the window film consists of a base layer and a coating layer, and when flexibility is excellent in both the base layer direction and the coating layer direction, the usability can be increased. In addition, since the window film is located at the outermost part of the display device, it is necessary to have excellent impact resistance to prevent damage to the panel, which is a weak part of the display.

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

An object of the present invention is to provide a composition for a window film capable of realizing a flexible window film having excellent hardness and impact resistance.

Another object of the present invention is to provide a composition for a window film capable of realizing a flexible window film having excellent flexibility in both the compression direction and the tensile direction.

Another object of the present invention is to provide a composition for a window film capable of realizing a flexible window film having a low haze.

The composition for a window film of the present invention may include a siloxane resin represented by the following Chemical Formula 1, a crosslinking agent, and an initiator:

<Formula 1>

(R ¹ SiO _3/2 ) _x (R ² R ³ SiO _2/2 ) _y (R ⁴ -[-O-(C=O)NH-R ⁵ -SiO _3/2 ] _n ) _z

(In Formula 1, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , n, x, y, and z are as defined in the detailed description below).

The flexible window film of the present invention may include a base layer and a coating layer formed on the base layer, and the coating layer may be formed of the composition for the window film.

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

The present invention provides a composition for a window film capable of realizing a flexible window film having excellent hardness and impact resistance.

The present invention provides a composition for a window film capable of realizing a flexible window film having excellent flexibility in both the compression direction and the tensile direction.

The present invention provides a composition for a window film capable of realizing a flexible window film having a low haze.

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 flexible display device according to an embodiment of the present invention.
5 is a cross-sectional view of a flexible display device according to another embodiment of the present invention.
6 is a cross-sectional view of a flexible display device according to another embodiment of the present invention.

With reference to the accompanying drawings, the embodiments will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In this specification, "upper" and "lower" are defined based on the drawings, and depending on the perspective of the city, "upper" may be changed to "lower" and "lower" to "upper", and "on" or What is referred to as “on” may include cases where other structures are interposed in the middle as well as immediately above. On the other hand, "directly on" or "directly on" means that other structures are not interposed therebetween.

In the present specification, "pencil hardness" is measured by the JIS K5400 method using a pencil hardness meter (Heidon) for the coating layer of the window film. For measuring pencil hardness, Mitsubishi's 6B to 9H pencils were used. The load of the pencil with respect to the coating layer was 1 kg, the angle of drawing a pencil was 45 degrees, and the speed of drawing a pencil was 60 mm/min. If scratch occurs more than once after evaluating 5 times, it is measured using a pencil of the lower level of pencil hardness, and when evaluated 5 times, it is the maximum pencil hardness value when there are no scratches in all 5 times.

As used herein, "radius of curvature" means winding a window film specimen on a JIG (CFT-200R, COVOTECH Co.) for a radius of curvature test, maintaining the wound state for 5 seconds, unwinding the test piece, and visually inspecting whether a crack has occurred in the test piece. It means the minimum radius of the JIG where cracks do not occur by checking. The radius of curvature in the compression direction was measured with the coating layer in the window film in contact with the JIG surface. The radius of curvature in the tensile direction was measured by assuming that the base layer in the window film was in contact with the JIG.

As used herein, "alicyclic epoxy group" means an epoxidized C4 to C20 cycloalkyl group. For example, the alicyclic epoxy group may be an epoxycyclohexyl group. As used herein, the "functional group containing an alicyclic epoxy group" refers to a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C5 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 group having an alicyclic epoxy group. means an aryl group. For example, the functional group containing an alicyclic epoxy group may be an epoxycyclohexylethyl group or an epoxycyclohexylmethyl group.

As used herein, "glycidyl group-containing functional group" refers to a substituted or unsubstituted C1 to C20 alkyl group having a glycidyl group, a glycidyl group or a glycidoxy group, a substituted or unsubstituted C5 having a glycidyl group or a glycidoxy group. to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group having a glycidyl group or a glycidoxy group. For example, the functional group containing a glycidyl group may be a glycidoxypropyl group.

As used herein, "(meth) acryl" means acryl or methacrylic. As used herein, "(meth)acryl-containing functional group" refers to a substituted or unsubstituted C1 to C20 alkyl group having (meth)acryl. For example, it may be a substituted or unsubstituted C1 to C5 alkyl group having (meth)acryl.

As used herein, "(meth)acryloxy group-containing functional group" refers to a substituted or unsubstituted C1 to C20 alkyl group having a (meth)acryloxy group. For example, it may be a substituted or unsubstituted C1 to C5 alkyl group having a (meth)acryloxy group. For example, the (meth)acryloxy group-containing functional group may be a (meth)acryloxypropyl group or a (meth)acryloxyethyl group.

In the present specification, unless otherwise specified, "substituted" means that at least one hydrogen atom of a functional group is a hydroxyl group, an unsubstituted C1 to C10 alkyl group, a C1 to C10 alkoxy group, a C3 to C10 cycloalkyl group, an unsubstituted C6 to It means substituted with a C1 to C10 alkyl group substituted with a C20 aryl group, a C7 to C20 arylalkyl group, a benzophenone group, a C1 to C10 alkyl group, or a C1 to C10 alkoxy group. do.

As used herein, "halogen" means fluorine, chlorine, bromine or iodine.

As used herein, "Ec" refers to a 2-(3,4-epoxycyclohexyl)ethyl group, and "Gp" refers to a 3-glycidoxypropyl group. "Et" means an ethyl group. "Pr" means a propyl group.

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

The composition for a window film according to an embodiment of the present invention may include a siloxane resin of Formula 1 below, a crosslinking agent, and an initiator:

<Formula 1>

(R ¹ SiO _3/2 ) _x (R ² R ³ SiO _2/2 ) _y (R ⁴ -[-O-(C=O)NH-R ⁵ -SiO _3/2 ] _n ) _z

(In Formula 1, R ¹ is an alicyclic epoxy group, an alicyclic epoxy group-containing functional group, a glycidyl group, a glycidyl group-containing functional group, a (meth)acryl group, a (meth)acryloxy group, a (meth)acryl group-containing functional group, or (meth) acryloxy group-containing functional group,

R ² and R ³ are each independently an alicyclic epoxy group, an alicyclic epoxy group-containing functional group, a glycidyl group, a glycidyl group-containing functional group, a (meth)acryl group, a (meth)acryloxy group, a (meth)acryl group-containing functional group , a (meth) acryloxy group-containing functional group, or a substituted or unsubstituted C1 to C10 alkyl group,

R ⁴ is a substituted or unsubstituted C2 to C20 alkylene group or (R ⁶ -O-)mR ⁷ (R ⁶ and R ⁷ are each independently a substituted or unsubstituted C2 to C5 alkylene group, m is 1 to an integer of 5), and

R ⁵ is a substituted or unsubstituted C1 to C12 alkylene group

n is an integer from 2 to 4,

0≤x<1, 0≤y<1, 0<z<1, x+y+z=1, x+y≠0,

When x is 0, at least one of R ² and R ³ is an alicyclic epoxy group, a functional group containing an alicyclic epoxy group, a glycidyl group, a functional group containing a glycidyl group, a (meth)acryl group, a (meth)acryloxy group, ( a functional group containing a meth)acryl group or a functional group containing a (meth)acryloxy group).

The composition for a window film according to the present embodiment includes a siloxane resin including (R ⁴ -[-O-(C=O)NH-R ⁵ -SiO _{3 / 2} ] _n ). It is a siloxane unit having a urethane bond and a bridge structure at the same time. Accordingly, the composition for a window film may have improved radius of curvature in the tensile direction and impact resistance, and may prevent gelation during manufacturing of the siloxane resin. instead of the siloxane resin comprising (R ⁴ -[-O-(C=O)NH-R ⁵ -SiO _3/2 ] _n ), (R ¹ SiO _{3 /2} ) Units, (R ² R ³ SiO _{2 /2} ) A composition for a window film in which a siloxane resin composed of at least one unit and a urethane-containing compound is simply mixed may cause cloudiness or cracks during the aging process during the window film manufacturing process. The effect of lowering the radius of curvature cannot be obtained either.

Specifically, the siloxane resin of Formula 1 (R ⁴ -[-O-(C=O)NH-R ⁵ -SiO _{3 / 2} ] _n ) is more than 0 mol% and 20 mol% or less, specifically 1 mol% to 20 mol%, It may be included in an amount of 1 mol% to 10 mol%. In addition, the siloxane resin of Chemical Formula 1 (R ¹ SiO _{3 /2} ), (R ² R ³ SiO _{2 / 2} ) is prepared by adjusting the ratio of each silicone monomer for, increasing the hardness of the window film, the hardness and It can facilitate the adjustment of flexibility.

Specifically, in Formula 1, R ⁴ is a substituted or unsubstituted C2 to C10 alkylene group or (R ⁶ -O-)mR ⁷ (R ⁶ and R ⁷ are each independently a substituted or unsubstituted C2 to C5 alkylene group, m is an integer of 1 to 5), more specifically, a propylene group, a butylene group, (CH ₂ CH ₂ -O-)-CH ₂ CH ₂ , (CH ₂ CH ₂ -O-) ₂ -CH ₂ CH ₂ , (CH ₂ CH ₂ -O-) ₃ -CH ₂ CH ₂ and the like.

Specifically, in Formula 1, R ⁵ may be a substituted or unsubstituted C1 to C5 alkylene group, for example, a propylene group, and n may be an integer from 2 to 4, for example, 2, 3, or 4.

R ¹ of Formula 1 may provide cross-linking properties to the composition for a window film and reduce curling of the window film. Specifically, R ¹ is an alicyclic epoxy group-containing functional group, a glycidyl group-containing functional group, more specifically, (3,4-epoxycyclohexyl)methyl group, (3,4-epoxycyclohexyl)ethyl group, 3-glycidoxypropyl group It can be a flag, etc. R ¹ may be a (meth)acryloxy group-containing functional group, more specifically, a (meth)acryloxypropyl group, (meth)acryloxyethyl group, or the like. Through this, the effect of increasing the hardness and flexibility of the window film and lowering the curl may be greater.

R ² and R ³ of Formula 1 may provide cross-linking properties, increase hardness and flexibility of the window film, reduce curl, and improve coating properties of the composition for a window film to improve the appearance of the film. Specifically, R ² and R ³ are an alicyclic epoxy group-containing functional group, more specifically, a (3,4-epoxycyclohexyl)methyl group, a (3,4-epoxycyclohexyl)ethyl group, a (meth)acryloxy group-containing functional group, More specifically, it may be an unsubstituted C1 to C5 alkyl group such as a (meth)acryloxypropyl group, a (meth)acryloxyethyl group, a methyl group or an ethyl group.

Specifically, in Formula 1, 0.80≤x≤0.99, y=0, 0.01≤z≤0.20, x+y+z=1, more specifically 0.90≤x≤0.99, y=0, 0.01≤z≤0.10, It can be x+y+z=1. In addition, in Formula 1, x=0, 0.80≤y≤0.99, 0.01≤z≤0.20, x+y+z=1, more specifically, x=0, 0.90≤y≤0.99, 0.01≤z≤0.10, x It can be +y+z=1. Within the above range, the window film may have good hardness, flexibility and appearance, and excellent impact resistance.

Specifically, the siloxane resin of Formula 1 may include any one of Formulas 1-1 to 1-6, but is not limited thereto:

<Formula 1-1>

(EcSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-OC ₄ H ₈ -O-(C=O)NH-C ₃ H ₆ -SiO _3/2 ) _z

<Formula 1-2>

(EcSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-O-(CH ₂ CH ₂ O) ₂ -CH ₂ CH ₂ -O-(C=O)NH- C ₃ H ₆ -SiO _3/2 ) _z

<Formula 1-3>

((meth)acryloxy-PrSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-OC ₄ H ₈ -O-(C=O)NH _- C ₃ H ₆ - SiO _{3 / 2} ) _z

<Formula 1-4>

((meth)acryloxy-PrSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-O-(CH ₂ CH ₂ O) ₂ -CH ₂ CH ₂ -O- ₍ C=O)NH-C ₃ H ₆ -SiO _3/2 ) _z

<Formula 1-5>

(GpSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-OC ₄ H ₈ -O-(C=O)NH-C ₃ H ₆ -SiO _3/2 ) _z

<Formula 1-6>

(GpSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-O-(CH ₂ CH ₂ O) ₂ -CH ₂ CH ₂ -O-(C=O)NH- C ₃ H ₆ -SiO _3/2 ) _z

(In Formulas 1-1 to 1-6, x, y, and z are the same as defined in Formula 1).

The siloxane resin of Formula 1 may have a weight average molecular weight of 5,000 to 100,000, specifically 5,000 to 25,000. In the above range, the siloxane resin may be easily manufactured and may have excellent hardness and flexibility. The siloxane resin of Formula 1 may have a polydispersity (PDI) of 1.0 to 3.0, specifically 1.5 to 2.5. In the above range, the coating property of the composition for a window film may be good and the coating properties may have a stable effect.

The siloxane resin of Formula 1 is at least one (R ¹ SiO _{3 /2} ), one or more (R ² R ³ SiO _{2 /2} ), and one or more (R ⁴ -[-O-(C=O)NH-R ⁵ -SiO _{3 / 2} ] _n ). The siloxane resin of Formula 1 may be included in the composition for a window film alone or in combination of two or more.

The siloxane resin of Formula 1 may include at least one of a first silicone monomer and a second silicone monomer; And it may be prepared by hydrolysis and condensation reaction of a monomer mixture including a third silicone monomer.

The first silicone monomer may be a silane compound having an R ¹ group of Formula 1 above. Specifically, the first silicone monomer may be represented by Formula 2 below. These may be used alone or in combination of two or more:

<Formula 2>

SiR ¹ R ⁸ R ⁹ R ¹⁰

(In Formula 2, R ¹ is as defined in Formula 1, and R ⁸ , R ⁹ and R ¹⁰ are each independently halogen, a hydroxyl group, or a C1 to C10 alkoxy group). More specifically, the first silicone monomer is 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltri methoxysilane, 3-glycidoxypropyltriethoxysilane, and the like.

The second silicone monomer may be a silane compound having R ² and R ³ of Formula 1 above. Specifically, the second silicone monomer may be represented by the following Chemical Formula 3: These may be used alone or in mixture of two or more:

<Formula 3>

SiR ² R ³ R ¹¹ R ¹²

(In Formula 3, R ² and R ³ are as defined in Formula 1, and R ¹¹ and R ¹² are each independently halogen, a hydroxyl group, or a C1 to C10 alkoxy group). More specifically, the second silicone monomer may be dimethyldimethoxysilane, diethylmethoxyethoxysilane, ethylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldimethoxysilane, or the like.

The third silicone monomer may be represented by the following formula (4), and may be included alone or in a mixture of two or more:

<Formula 4>

R ⁴ -[-O-(C=O)NH-R ⁵ -SiR ¹³ R ¹⁴ R ¹⁵ ] _n

(In Formula 4, R ⁴ , R ⁵ , and n are as defined in Formula 1 above, and R ¹³ , R ¹⁴ , R ¹⁵ is each independently a halogen, a hydroxyl group, or a C1 to C10 alkoxy group).

As the third silicone monomer, commercially available products may be used or may be obtained by synthesis. For example, the third silicone monomer may be prepared by reacting a polyol having 2 to 4 OH groups with trialkoxysilane having an isocyanate group. As a catalyst for increasing the reaction yield and catalyzing the reaction, a tin catalyst such as dibutyltin dilaurate may be used. The polyol may be propanediol, butanediol, diethylene glycol, triethylene glycol, or the like. The trialkoxysilane having an isocyanate group may be isocyanatopropyltriethoxysilane or the like. The present invention is not limited thereto.

The hydrolysis and condensation reaction of the monomer may be performed according to a conventional method for preparing a siloxane resin. Hydrolysis may comprise reacting the monomer mixture in water and a mixture of one or more of the desired acids, bases. Specifically, the acid may be acetic acid, formic acid, hydrochloric acid, and the base may be NaOH, KOH, K ₂ CO ₃ , or the like. Hydrolysis may be performed at 20°C to 100°C for 10 minutes to 7 hours. In the above range, it is possible to increase the hydrolysis efficiency. The condensation reaction may be performed at 20°C to 100°C for 10 minutes to 12 hours under the same or different conditions as hydrolysis. In the above range, it is possible to increase the efficiency of the condensation reaction.

The crosslinking agent may further increase the hardness of the window film by containing a crosslinkable functional group. The crosslinking agent may further increase the flexibility of the window film. Specifically, the crosslinking agent may include at least one of a monomer having an epoxy group, a monomer having a (meth)acryl group, and a monomer having a (meth)acryloxy group. When y=0 in Formula 1, a monomer having an epoxy group may be used as a crosslinking agent. When x=0 in Formula 1, the crosslinking agent may include at least one of a monomer having a (meth)acryl group and a monomer having a (meth)acryloxy group.

The monomer having an epoxy group may include at least one of a non-cyclic aliphatic epoxy monomer, a cyclic aliphatic epoxy monomer, an aromatic epoxy monomer, and a hydrogenated aromatic epoxy monomer.

Non-cyclic aliphatic epoxy monomers include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, glycerin triglycidyl ether, polypropylene glycol diglycidyl ether; polyglycidyl ethers of polyether polyols obtained by adding one or more kinds of 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 epoxystearate; octyl epoxy stearate; epoxidized linseed oil; Epoxidation polybutadiene etc. are mentioned.

The cyclic aliphatic epoxy monomer is a compound having one or more epoxy groups in the alicyclic group, and specifically, may 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, bis(3,4-epoxy-6-methylcyclohexyl)adipate, 3,4-epoxy-6 -Methylcyclohexylmethyl-3',4'-epoxy-6'-methylcyclohexanecarboxylate, ε-caprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate , trimethylcaprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, β-methyl-δ-valerolactone-modified 3,4-epoxycyclohexylmethyl-3'4, '-Epoxycyclohexanecarboxylate, 1,4-cyclohexanedimethanol bis(3,4-epoxycyclohexanecarboxylate), di(3,4-epoxycyclohexylmethyl)ether of ethylene glycol, ethylenebis( 3,4-epoxycyclohexanecarboxylate)), 3,4-epoxycyclohexylmethyl (meth)acrylate, bis (3,4-epoxycyclohexylmethyl) adipate, 4-vinylcyclohexene dioxide, Vinyl cyclohexene monooxide etc. are mentioned.

Examples of the aromatic epoxy monomer include bisphenol-type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S; novolak-type epoxy resins such as phenol novolac epoxy resins, cresol novolac epoxy resins, and hydroxybenzaldehyde phenol novolac epoxy resins; and polyfunctional epoxy resins such as glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, and epoxidized polyvinyl phenol.

The hydrogenated aromatic epoxy monomer means a monomer obtained by selectively hydrogenating an aromatic epoxy monomer under pressure in the presence of a catalyst. The aromatic epoxy monomer for the hydrogenated aromatic epoxy monomer may include the aforementioned aromatic epoxy monomer.

The monomer having a (meth)acryl group and the monomer having a (meth)acryloxy group may include one or more, preferably two or more, 2 to 6 (meth)acryl groups or monomers having a (meth)acryloxy group. there is. For example, a monomer having a (meth)acryl group and a monomer having a (meth)acryloxy group include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentylglycol di (meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate , Ethylene oxide-modified di(meth)acrylate, di(meth)acryloxy ethyl isocyanurate, allylated cyclohexyl di(meth)acrylate, tricyclodecanedimethanol (meth)acrylate, dimethylol dicyclo Pentane di (meth) acrylate, ethylene oxide-modified hexahydrophthalic acid di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, neopentyl glycol-modified trimethyl propane di (meth) acrylate, adamantane ( adamantane) di(meth)acrylate or difunctional (meth)acrylate such as 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene; Trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxyray Ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide, including tide (6) trimethylolpropane tri(meth)acrylate, ethoxylated (9) trimethylolpropane tri(meth)acrylate, etc. trifunctional (meth)acrylates such as seed-modified trimethylolpropane tri(meth)acrylate, trifunctional urethane (meth)acrylate, or tris(meth)acryloxyethyl isocyanurate; tetrafunctional (meth)acrylates such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; 5-functional (meth)acrylates, such as dipentaerythritol penta (meth)acrylate; And dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate or urethane (meth) acrylate (ex. isocyanate monomer and trimethylolpropane tri (meth) acrylate 6-functional (meth)acrylates such as reactants may be mentioned, but the present invention is not limited thereto.

The crosslinking agent may be included in an amount of 0.1 parts by weight to 50 parts by weight, specifically 1 part by weight to 40 parts by weight, and more specifically 5 parts by weight to 30 parts by weight based on 100 parts by weight of the siloxane resin of Formula 1. In the above range, there may be an effect of increasing the flexibility and hardness of the window film.

The initiator may cure the siloxane resin of Formula 1 and the crosslinking agent. The initiator may include at least one of a photocationic initiator and a photoradical initiator. The initiator may be used alone or in combination of two or more.

As the photocationic initiator, those commonly known to those skilled in the art may be used. Specifically, the photocationic initiator may include at least one onium salt including a cation and an anion. Specifically, the cation is diphenyliodonium, 4-methoxydiphenyliodonium, bis(4-methylphenyl)iodonium, bis(4-tert-butylphenyl)iodonium, bis(dodecylphenyl)iodonium, (4 -methylphenyl)[(4-(2-methylpropyl)phenyl)diaryliodonium such as iodonium, triphenylsulfonium, diphenyl-4-thiophenylphenylsulfonium, diphenyl-4-thiophenoxyphenyl triarylsulfonium, such as sulfonium, bis[4-(diphenylsulfonio)phenyl]sulfide, etc. are mentioned. Specifically, the anion is hexafluorophosphate (PF ₆ ^- ), tetrafluoroborate (BF ₄ ^- ), hexafluoroantimonate (SbF ₆ ^- ), hexafluoroarsenate (AsF ₆ ^- ), hexa and chloroantimonate (SbCl ₆ ⁻ ).

As the photoradical initiator, those commonly known to those skilled in the art may be used. Specifically, the photoradical initiator may include at least one of a hydroxyketone-based, thioxanthone-based, phosphorus-based, triazine-based, acetophenone-based, benzophenone-based, benzoin-based, and oxime-based initiator. For example, the photoradical initiator is 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'-diethoxy acetophenone, 2,2 '-dibutoxy acetophenone, 2-hydroxy-2-methyl propiophenone, pt-butyl trichloro acetophenone, pt-butyl dichloro acetophenone, 4-chloro acetophenone, 2,2'-dichloro-4-phenoxy Acetophenone compounds such as acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl- 1-phenylpropan-1one, 2-benzyl-2-dimethyl amino-1-(4-morpholino phenyl)-butan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[ 4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenyl Benzophenone, 4,4-noncydiethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2 -Ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethylketal, p-dimethylamino benzoic acid ester, oligo[2-hydroxy -2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] and the like.

The initiator may be included in an amount of 0.01 parts by weight to 10 parts by weight, specifically 1 part by weight to 5 parts by weight, based on 100 parts by weight of the siloxane resin of Formula 1. In the above range, the siloxane resin may be sufficiently cured, and the remaining amount of the initiator may prevent deterioration of transparency and light resistance of the window film.

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

The nanoparticles may 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. Part or all of the surface of the nanoparticles may be surface-treated with a silicone compound for mixing with the siloxane resin. Nanoparticles are not limited in shape or size. Specifically, the nanoparticles may include particles having a shape such as a spherical shape, a plate shape, or an amorphous shape. The nanoparticles may have an average particle diameter of 1 nm to 200 nm, specifically 10 nm to 50 nm. Within the above range, the hardness of the window film may be increased without affecting the surface roughness and transparency of the window film. The nanoparticles may be included in an amount of 0.1 parts by weight to 60 parts by weight, specifically 10 parts by weight to 50 parts by weight, based on 100 parts by weight of the siloxane resin of Formula 1. Within the above range, the hardness of the window film may be increased without affecting the surface roughness and transparency of the window film.

The composition for a window film according to the present embodiment may further include an additive. Additives may provide additional functionality to the window film. The additive may include an additive that is conventionally 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 enhancer, a thixotropic agent, a conductivity-imparting agent, a color adjuster, a stabilizer, an antistatic agent, an antioxidant, and a leveling agent does not The reaction inhibitor may include ethynylcyclohexane. The adhesion improving agent may include a silane compound having an epoxy or alkoxysilyl group. The thixotropic agent may include fumed silica and the like. The conductivity-imparting agent may include a metal powder such as silver or copper aluminum. The color adjusting agent may include a pigment, a dye, and the like. The UV absorber may increase the light resistance reliability of the window film. As the UV absorber, conventional absorbers known to those skilled in the art may be used. Specifically, the UV absorber may include at least one of a triazine-based, benzimidazole-based, benzophenone-based, and benzotriazole-based UV absorber, but is not limited thereto. The additive may be included in an amount of 0.01 parts by weight to 5 parts by weight, specifically 0.1 parts by weight to 2.5 parts by weight, based on 100 parts by weight of the siloxane resin of Formula 1. In the above range, it is possible to improve the hardness and flexibility of the window film and implement the additive effect.

The composition for a window film according to the present embodiment may further include a solvent to facilitate coatability, coatability, or processability. The solvent may include, but is not limited to, one or more of methyl ethyl ketone, methyl isobutyl ketone, and propylene glycol monomethyl ether acetate.

The composition for a window film according to the present embodiment may have a viscosity of 50 cP to 2000 cP at 25°C. Formation of the window film in the above range may be easy.

Hereinafter, a flexible window film according to an embodiment of the present invention will be described with reference to FIG. 1 . 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 the composition for a window film according to an embodiment of the present invention.

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

The base layer 110 may be formed of an optically transparent and flexible resin. For example, the resin includes a polyester resin including polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polycarbonate resin, polyimide resin, polystyrene resin, polymethyl methacrylate, etc. It may include at least one of a poly (meth) acrylate resin and a cycloolefin polymer resin. The resin may be included in the base layer 110 alone or in combination.

The base layer 110 may have a thickness of 10 μm to 200 μm, specifically 20 μm to 150 μm, and more specifically 30 μm to 100 μm. It 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 and the display unit, the touch screen panel or the polarizing plate, and has high flexibility and high hardness, so that it can be used in a flexible display device.

The coating layer 120 may have a thickness of 5 μm to 100 μm, specifically 10 μm to 80 μm, and more specifically 10 μm to 50 μm. It may be used in a flexible window film in the above range, and the hardness of the window film may be good.

Although not shown in FIG. 1 , a functional surface layer such as an anti-reflection layer, an anti-glare layer, and a hard coating layer is further formed on the other surface of the coating layer 120 to provide an additional function to the flexible window film. In addition, although not shown in FIG. 1 , the coating layer 120 may be further formed on the other surface of the base layer 110 .

Since the flexible window film 100 is optically transparent, it can be used in a transparent display device. Specifically, the flexible window film 100 may have a haze of 3% or less, specifically 2% or less, and 1% or less in a visible light region, specifically, a wavelength of 400 nm to 800 nm. It can be used as a flexible window film in the above range.

The flexible window film 100 may have a pencil hardness of 3H or more and a radius of curvature in the tensile direction of 5.0 mm or less and a radius of curvature in the compression direction of less than 2.5 mm. Within the above range, it may be used as a flexible window film having good hardness and flexibility. The "radius of curvature in the tensile direction" is a radius of curvature measured when the window film is folded toward the base layer after the base layer of the window film is in contact with the jig for measuring the radius of curvature. The "compression direction radius of curvature" is a radius of curvature measured when the window film is folded toward the window coating layer after the window coating layer of the window film is in contact with the jig for measuring the radius of curvature. Specifically, the flexible window film 100 may have a pencil hardness of 3H to 9H, a radius of curvature in the tensile direction of 2 mm or less, and a radius of curvature in the compression direction of 1.0 mm or less.

The flexible window film 100 may have an impact resistance of 5 cm or more according to the PEN DROP TEST below. Within the above range, it is possible to prevent damage to the panel when mounted on an OLED panel due to good impact resistance. In this case, the OLED panel may include an OELD panel commonly used by those skilled in the art. For example, the impact resistance may be 5 mm to 20 mm.

The flexible window film 100 may have a thickness of 50 μm to 300 μm. It can be used as a flexible window film in the above range.

The flexible window film 100 may be manufactured by a method of manufacturing a flexible window film including coating and curing the composition for a window film according to an embodiment of the present invention on the base layer 110 .

A method of coating the composition for a window film on the base layer 110 is not particularly limited. For example, it may be bar coating, spin coating, dip coating, roll coating, flow coating, die coating, and the like. The composition for a window film may be coated on the base layer 110 to a thickness of 5 μm to 100 μm. A desired coating layer may be secured within the above range, and there may be an effect of excellent hardness, flexibility, and reliability.

Curing is to form a coating layer by curing the composition for a window film, and may include at least one of photocuring and thermal curing. Photocuring may include irradiating with a light quantity of 10 mJ/cm ² to 1000mJ/cm ² at a wavelength of 400 nm or less. Thermal curing may include treatment at 40° C. to 200° C. for 1 hour to 30 hours. In the above range, the composition for a window film may be sufficiently cured. For example, it may be thermally cured after photocuring, and as a result, the hardness of the coating layer may be further increased.

After coating the composition for a window film on the base layer 110 and before curing the composition, the method may further include drying the composition for a window film. By curing after drying, it is possible to prevent the surface roughness of the coating layer from increasing due to long-term photocuring and thermal curing. Drying may be performed at 40° C. to 200° C. for 1 minute to 30 hours, but is not limited thereto.

Hereinafter, a flexible window film according to another embodiment of the present invention will be described with reference to FIG. 2 . 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 a base layer 110, a coating layer 120 formed on one surface of the base layer 110, and an adhesive layer 130 formed on the other surface of the base layer 110, The coating layer 120 may be formed of the composition for a window film according to an embodiment of the present invention.

By further forming the adhesive layer 130 on the other surface of the substrate layer 110, it is possible to facilitate adhesion between the flexible window film and the touch screen panel, the polarizing plate, or the display unit. It 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. Accordingly, only the adhesive layer 130 will be described below.

The adhesive layer 130 adheres to a polarizing plate, a touch screen panel, or a display that may be disposed under the flexible window film 200 , and may be formed of a composition for an adhesive layer. Specifically, the adhesive layer 130 may be formed of a composition for an adhesive layer including a (meth)acrylic resin, a urethane resin, a silicone resin, an adhesive resin such as 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, and the like, and may include a conventional (meth)acrylic copolymer. Specifically, a (meth)acrylic monomer having a C1 to C10 unsubstituted alkyl group, a (meth)acrylic monomer having a C1 to C10 alkyl group having one or more hydroxyl groups, a C6 to C20 aromatic group (meth)acrylic monomer , a (meth)acrylic monomer having a carboxylic acid group, a (meth)acrylic monomer having a C3 to C20 alicyclic group, nitrogen (N), oxygen (O), sulfur (S) having at least one of C3 to C10 heteroalicyclic It may be formed of a monomer mixture comprising at least one of (meth)acrylic monomers having a group.

The curing agent is a polyfunctional (meth)acrylate, and may be a bifunctional (meth)acrylate such as hexanediol diacrylate; trifunctional (meth)acrylate of trimethylolpropane tri(meth)acrylate; tetrafunctional (meth)acrylates such as pentaerythritol tetra(meth)acrylate; 5-functional (meth)acrylates, such as dipentaerythritol penta (meth)acrylate; It may include, but is not limited to, a hexa-functional (meth)acrylate such as dipentaerythritol hexa(meth)acrylate.

The photoinitiator may include the above-mentioned photoradical initiator as a conventional photoinitiator.

The silane coupling agent may include a silane coupling agent having an epoxy group, such as 3-glycidoxypropyltrimethoxysilane.

The composition for an adhesive layer may include 100 parts by weight of a (meth)acrylic resin, 0.1 parts by weight to 30 parts by weight of a curing agent, 0.1 parts by weight to 10 parts by weight of a photoinitiator, and 0.1 parts by weight to 20 parts by weight of a silane coupling agent. In the above range, the flexible window film may be well attached to the display unit, the touch screen panel or the polarizing plate.

The adhesive layer 130 may have a thickness of 10 μm to 100 μm. In the above range, it is possible to sufficiently adhere an optical element such as a flexible window film and a polarizing plate.

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

Referring to FIG. 3 , the flexible window film 150 is substantially the same as the flexible window film 100 according to the present embodiment, except that the substrate layer 110A is included instead of the substrate layer 110 . .

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 may have excellent flexibility and further improved impact resistance compared to the case of using the base layer 110 .

The first film 110a and the second film 110b may support the flexible window film 150 , respectively. Each of the first film 110a and the second film 110b may be formed of the optically transparent and flexible resin. The first film 110a and the second film 110b may be formed of the same or different types of resin. For example, each of the first film 110a and the second film 110b is 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. It may be a film.

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

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

3 shows a case in which the coating layer 120 is directly formed on the second film 110b, but when the coating layer 120 is directly formed on the first film 110a, that is, the second film 110b, the adhesive layer ( 110c), a case in which the first film 110a, and the coating layer 120 are sequentially formed may also be included in the scope of the present invention.

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 may increase reliability in bending during repeated folding of the window film, and may increase the impact strength of the window film.

The adhesive layer 110c may have a modulus of 10 kPa to 1000 kPa at 25°C. Within the above range, the impact resistance of the window film may be increased, and reliability may be good even when the window film is folded once or repeatedly at room temperature. Preferably, the adhesive layer 120 may have a modulus of 10 kPa to 800 kPa at 25°C.

The adhesive layer 110c may have a modulus of 10 kPa to 1000 kPa at 80°C. Within the above range, the impact resistance of the window film may be increased, and reliability may be good even in one or repeated folding of the window film at high temperature and high humidity. Preferably, the adhesive layer 110c may have a modulus of 10 kPa to 800 kPa at 80°C.

The adhesive layer 110c may have a modulus of 10 kPa to 1000 kPa at -20°C. In the above range, the impact resistance of the window film may be increased, and reliability may be good even in one or repeated folding of the window film at a low temperature. Preferably, the adhesive layer 110c may have a modulus of 10 kPa to 500 kPa at -20°C.

The adhesive layer 110c may have a thickness of 10 μm to 75 μm. Within the above range, there may be an effect excellent in flexibility and impact resistance. Preferably, the adhesive layer 110c may have a thickness of 10 μm to 50 μm or 10 μm to 30 μm.

The adhesive layer 110c may be formed of an optical clear adhesive (OCA). The adhesive layer 110c may include a monomer mixture for a (meth)acrylic copolymer having a hydroxyl group; initiator; And it may be formed of a composition for an adhesive layer comprising at least one of a macromonomer and organic nanoparticles. The monomer mixture may be included in the pressure-sensitive adhesive composition in the form of a non-polymerized monomer mixture, but the monomer mixture may be included as a partially polymerized partial polymer. Preferably, the composition for the adhesive layer includes 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 may provide 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 is 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 1,4-cyclohexanedimethanol mono (meth)acrylate, 1-chloro-2-hydr Roxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, Neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4- It may be at least one of hydroxycyclopentyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, and cyclohexanedimethanol mono(meth)acrylate. The hydroxyl group-containing (meth)acrylate is 5 wt% to 40 wt%, for example, 8 wt% to 30 wt%, 10 wt% to 30 wt% of the total of the hydroxyl group-containing (meth)acrylate and the alkyl group-containing (meth)acrylate It may be included in weight %. In the above range, adhesion and durability reliability of the adhesive layer may be further improved.

The alkyl group-containing (meth)acrylate may be a copolymer to form a matrix of the adhesive layer. The alkyl group-containing (meth)acrylate may include an unsubstituted linear or branched alkyl (meth)acrylic acid ester having 1 to 20 carbon atoms. For example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, iso-butyl (meth)acrylic Rate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, and isobornyl (meth)acrylate. The alkyl group-containing (meth)acrylate is 60 wt% to 95 wt%, for example 65 wt% to 92 wt%, 68 wt% to 90 wt% of the total of the hydroxyl group-containing (meth)acrylate and the alkyl group-containing (meth)acrylate Weight %, may be included in 70% to 90% by weight. In the above range, adhesion and durability reliability of the adhesive layer may be further improved.

The monomer mixture may further include a copolymerizable monomer. The copolymerizable monomer may be included in the (meth)acrylic copolymer to provide an additional effect to the (meth)acrylic copolymer, the pressure-sensitive adhesive composition or the pressure-sensitive adhesive layer. The copolymerizable monomer is a monomer different from the hydroxyl group-containing (meth)acrylate and the alkyl group-containing (meth)acrylate, a monomer having 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 , may include at least one of 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.

As the monomer having ethylene oxide, one or more (meth)acrylate-based monomers containing an ethylene oxide group (-CH ₂ CH ₂ O-) may be used. For example, polyethylene oxide monomethyl ether (meth) acrylate, polyethylene oxide monoethyl ether (meth) acrylate, polyethylene oxide monopropyl ether (meth) acrylate, polyethylene oxide monobutyl ether (meth) acrylate, polyethylene oxide mono Pentyl ether (meth) acrylate, polyethylene oxide dimethyl ether (meth) acrylate, polyethylene oxide diethyl ether (meth) acrylate, polyethylene oxide monoisopropyl ether (meth) acrylate, polyethylene oxide monoisobutyl ether (meth) It may be polyethylene oxide alkyl ether (meth) acrylate, such as acrylate, polyethylene oxide monotertbutyl ether (meth) acrylate, but is not necessarily limited thereto.

Monomers having propylene oxide include polypropylene oxide monomethyl ether (meth) acrylate, polypropylene oxide monoethyl ether (meth) acrylate, polypropylene oxide monopropyl ether (meth) acrylate, polypropylene oxide monobutyl ether (meth) ) acrylate, polypropylene oxide monopentyl ether (meth) acrylate, polypropylene oxide dimethyl ether (meth) acrylate, polypropylene oxide diethyl ether (meth) acrylate, polypropylene oxide monoisopropyl ether (meth) acrylic rate, polypropylene oxide monoisobutyl ether (meth) acrylate, polypropylene oxide alkyl ether (meth) acrylate, such as polypropylene oxide monotertbutyl ether (meth) acrylate, but is not necessarily limited thereto not.

The monomer having an amine group is monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, monoethylaminopropyl (meth)acrylate, dimethylaminoethyl (meth)acrylate ) Acrylate, diethylaminoethyl (meth)acrylate, N-tert-butylaminoethyl (meth)acrylate, (meth)acryloxyethyltrimethylammonium chloride (meth)acrylate containing amine groups (meth) It may be an acrylic monomer, but is not necessarily limited thereto.

The monomer having an alkoxy group is 2-methoxy ethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, 2-ethoxypropyl (meth) acrylate, 2-butoxypropyl (meth) acrylate, 2 -Methoxypentyl (meth)acrylate, 2-ethoxypentyl (meth)acrylate, 2-butoxyhexyl (meth)acrylate, 3-methoxypentyl (meth)acrylate, 3-ethoxypentyl (meth) ) acrylate or 3-butoxyhexyl (meth) acrylate, but is not necessarily limited thereto.

Monomers having a phosphoric acid group include 2-methacryloyloxyethyldiphenylphosphate (meth)acrylate, trimacryloyloxyethylphosphate (meth)acrylate, triacryloyloxyethylphosphate (meth)acrylate, etc. It may be an acrylic monomer having a phosphoric acid group, but is not necessarily limited thereto.

The monomer having a sulfonic acid group may be an acrylic monomer having a sulfonic acid group, such as sodium sulfopropyl (meth) acrylate, sodium 2-sulfoethyl (meth) acrylate, and sodium 2-acrylamido-2-methylpropanesulfonate. However, it is not necessarily limited thereto.

The monomer having a phenyl group may be an acrylic vinyl monomer having a phenyl group, such as p-tert-butylphenyl (meth) acrylate, o-biphenyl (meth) acrylate, phenoxyethyl (meth) acrylate, but must be limited thereto it is not going to be

The monomer having a silane group is 2-acetoacetoxyethyl (meth) acrylate, vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tris (2-methoxyethyl) silane, vinyl triacetoxysilane, (meth) acryl It may be a vinyl monomer having a silane group, such as royloxypropyltrimethoxysilane, but is not necessarily limited thereto.

The monomer having a carboxylic acid group is (meth)acrylic acid, 2-carboxyethyl (meth)acrylate, 3-carboxypropyl (meth)acrylate, 4-carboxybutyl (meth)acrylate, itaconic acid, crotonic acid, maleic acid, fumaric acid and maleic anhydride, but is not necessarily limited thereto.

Amide group-containing (meth)acrylate is (meth)acrylamide, N-methyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N,N-methylene bis(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, and N,N-diethyl(meth)acrylamide.

The copolymerizable monomer is included in an amount of 15 parts by weight or less, specifically 10 parts by weight or less, more specifically 0.05 to 8 parts by weight, based on 100 parts by weight of the total of 100 parts by weight of the hydroxyl group-containing (meth)acrylate and the alkyl group-containing (meth)acrylate. can In the above range, the pressure-sensitive adhesive composition may further improve the adhesion and recovery properties of the pressure-sensitive adhesive film.

The initiator may be used to cure (partial polymerization) 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. As the photopolymerization initiator, any one can be used as long as it can induce a polymerization reaction of the radically polymerizable compound described below in the curing process by light irradiation or the like. For example, a benzoin-based, hydroxy ketone-based, aminoketone-based or phosphine oxide-based photoinitiator may be used. The thermal polymerization initiator is not particularly limited as long as it has the above-described physical properties, and for example, a conventional initiator such as an azo-based compound, a peroxide-based compound, or a redox-based compound may be used. The initiator is 0.0001 parts by weight to 5 parts by weight, specifically 0.001 parts by weight to 3 parts by weight, based on 100 parts by weight of the total of the hydroxyl group-containing (meth)acrylate and the alkyl group-containing (meth)acrylate constituting the (meth)acrylic copolymer. may be included. In the above range, the curing reaction may proceed completely, and a residual amount of the initiator may be left to prevent a decrease in transmittance, and also, the generation of bubbles may be reduced and excellent reactivity may be obtained.

The macromonomer has a functional group curable by active energy ray and can be polymerized with hydroxyl group-containing (meth)acrylate and alkyl group-containing (meth)acrylate. Specifically, the macromonomer may be represented by the following Chemical Formula 5:

<Formula 5>

(In Formula 5, R ¹ is hydrogen or a methyl group, X is a single bond or a divalent bond group, Y is methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (a polymer chain obtained by polymerizing one or two or more selected from (meth)acrylate, t-butyl (meth)acrylate, styrene, and (meth)acrylonitrile).

The divalent bonding group is a C1 to C10 alkylene group, a C7 to C13 arylalkylene group, a C6 to C12 arylene group, -NR ² - (in this case, R ² is hydrogen or a C1 to C5 alkyl group), COO-, - It may be O-, -S-, -SO ₂ NH-, -NHSO ₂ -, -NHCOO-, -OCONH, or a group derived from a heterocycle.

In addition, the divalent bonding group may be represented by the following Chemical Formulas 5a to 5d:

<Formula 5a>

<Formula 5b>

<Formula 5c>

<Formula 5d>

(In Formulas 5a to 5d, * is a connection site of an element)

As the macromonomer, a commercially available product can be used. For example, a macromonomer whose terminal is a methacryloyl group and the segment corresponding to Y is methyl methacrylate, the segment corresponding to Y is a macromonomer whose segment is styrene, and the segment corresponding to Y is styrene/acrylic A macromonomer whose segment is ronitrile, a macromonomer whose segment corresponds to Y is butyl acrylate, and the like can be used.

The macromonomer is 20 parts by weight or less, specifically 0.1 to 20 parts by weight, 0.1 to 10 parts by weight, 0.5 parts by weight based on the total of 100 parts by weight of the hydroxyl group-containing (meth)acrylate and the alkyl group-containing (meth)acrylate. It may be included in parts by weight to 5 parts by weight. In the above range, it is possible to balance the viscoelasticity, modulus, and restoring force of the adhesive layer, and prevent haze increase of the adhesive layer.

The organic nanoparticles may have an average particle diameter of 10 nm to 400 nm, specifically 10 nm to 300 nm, more specifically 30 nm to 280 nm, and more specifically 50 nm to 280 nm. In the above range, it does not affect the folding of the adhesive layer, and the total light transmittance in the visible region is 90% or more, so that the transparency of the adhesive layer may be good.

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

The organic nanoparticles may include simple nanoparticles such as a core-shell type as well as a bead type, but is not limited thereto. In the case of the core-shell type, the core and the shell may satisfy Equation 1 below: That is, both the core and the shell may be nanoparticles of an organic material. In the case of having the particle shape as described above, the foldability of the adhesive layer is good, and there may be an effect on the balance properties of elasticity and flexibility.

<Equation 1>

Tg(c) < Tg(s)

(In Equation 1, Tg(c) is the glass transition temperature of the core (unit: °C), and Tg(s) is the glass transition temperature of the shell (unit: °C).

As used herein, the term “shell” refers to the outermost layer among organic nanoparticles. The core may be a single spherical particle. However, if the core has the above glass transition temperature, it may further include an additional layer surrounding the spherical particles.

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. In the above range, there may be a low-temperature and/or room-temperature viscoelastic effect of the adhesive layer. The core may include at least one of polyalkyl (meth)acrylate, polysiloxane, and polybutadiene having the above glass transition temperature.

Polyalkyl (meth) acrylate is polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, polybutyl acrylate, polyisopropyl acrylate, polyhexyl acrylate, polyhexyl methacrylate, polyethylhexyl acrylate And it may include one or more of polyethylhexyl methacrylate and polysiloxane, but is not necessarily limited thereto.

The polysiloxane can be, for example, an organosiloxane (co)polymer. Non-crosslinked organosiloxane (co)polymer may be used, or crosslinked (co)polymer may be used. A crosslinked organosiloxane (co)polymer may be used for impact resistance and colorability. This is a cross-linked organosiloxane, and specifically, cross-linked dimethylsiloxane, methylphenylsiloxane, diphenylsiloxane, or a mixture of two or more thereof may be used. By using a copolymerized form of two or more organosiloxanes, the refractive index of 1.41 to 1.50 can be adjusted.

The crosslinking state of the organosiloxane (co)polymer can be judged by the degree of dissolution by various organic solvents. The deeper the crosslinking state, the smaller the degree of dissolution by the solvent. Acetone or toluene may be used as a solvent for determining the crosslinking state, and specifically, the organosiloxane (co)polymer may have a portion that is not dissolved by acetone or toluene. The insoluble component in toluene of the organosiloxane copolymer may be 30% or more.

Additionally, the organosiloxane (co)polymer may further include an alkyl acrylate cross-linked polymer. The alkyl acrylate cross-linked polymer may be methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, or the like. 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 15 °C to 150 °C, specifically 35 °C to 150 °C, more specifically 50 °C to 140 °C. In the above range, the dispersibility of the organic nanoparticles in the (meth)acrylic copolymer may be excellent. The shell may include polyalkyl methacrylate having the glass transition temperature. For example, polymethyl methacrylate (PMMA), polyethyl methacrylate, polypropyl methacrylate, polybutyl methacrylate, polyisopropyl methacrylate, polyisobutyl methacrylate and polycyclohexyl methacrylate. rate may include, but is not necessarily limited to.

The core may be included in an amount of 30 wt% to 99 wt%, specifically 40 wt% to 95 wt%, and more specifically 50 wt% to 90 wt% of the organic nanoparticles. In the above range, the foldability of the adhesive layer may be good in a wide temperature range. The shell may be included in an amount of 1 wt% to 70 wt%, specifically 5 wt% to 60 wt%, and more specifically 10 wt% to 50 wt% of the organic nanoparticles. In the above range, the foldability of the adhesive layer may be good in a wide temperature range.

Organic nanoparticles are 0.1 parts by weight to 20 parts by weight, specifically 0.5 parts by weight to 10 parts by weight, specifically 0.5 parts by weight to 100 parts by weight of the total of 100 parts by weight of the hydroxyl group-containing (meth)acrylate and the alkyl group-containing (meth)acrylate It may be included in 8 parts by weight. In the above range, the modulus of the adhesive layer at high temperature may be increased, the foldability of the adhesive layer at room temperature and high temperature may be improved, and the low temperature and/or room temperature viscoelasticity of the adhesive layer may be excellent.

Organic nanoparticles may be prepared by conventional emulsion polymerization, suspension polymerization, and solution polymerization methods.

The pressure-sensitive adhesive layer composition may further include a silane coupling agent. As a silane coupling agent, a conventional one known to those skilled in the art may be used. For example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyl dimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltri silicon compounds having an epoxy structure such as methoxysilane; Polymerizable unsaturated group containing silicon compounds, such as vinyl trimethoxy silane, vinyl triethoxy silane, and (meth)acryloxy propyl trimethoxysilane; Silicon compounds containing amino groups, such as 3-aminopropyl trimethoxysilane, N-(2-aminoethyl)-3-aminopropyl trimethoxysilane, and N-(2-aminoethyl)-3-aminopropyl methyl dimethoxysilane ; And it may include one or more selected from the group consisting of 3-chloro propyl trimethoxysilane and the like, but is not limited thereto. The silane coupling agent may be included in an amount of 0.01 to 3 parts by weight, specifically 0.01 to 1 part by weight, based on 100 parts by weight of the total of the hydroxyl group-containing (meth)acrylate and the alkyl group-containing (meth)acrylate. In the above range, reliability may be secured in the bending state at high temperature and high humidity described above, and the difference in peel force between low temperature, room temperature, and high temperature may be low.

The composition for the adhesive layer may further include a crosslinking agent. The crosslinking agent may increase the degree of crosslinking of the composition for an adhesive layer to increase the mechanical strength of the adhesive layer. The crosslinking agent may include a polyfunctional (meth) acrylate that can be cured with active energy rays, for example, a bifunctional (meth) acrylate such as hexanediol diacrylate, or a trifunctional to hexafunctional (meth) acrylate. can The crosslinking agent is 0.001 parts by weight to 5 parts by weight, specifically 0.003 parts by weight to 3 parts by weight, specifically 0.005 parts by weight to 1 parts by weight, based on 100 parts by weight of the total of the hydroxyl group-containing (meth)acrylate and the alkyl group-containing (meth)acrylate may be included as a part. In the above range, there is an effect of excellent adhesion and reliability increase.

3 shows a case in which the base layer is a film laminate in which the first film 110a and the second film 110b are laminated by the adhesive layer 110c. However, a case in which the base layer includes three or more films and at least two or more of them are laminated on each other by the adhesive layer 110c may also 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 . 4 is a cross-sectional view of a flexible display device according to an embodiment of the present invention.

Referring to FIG. 4 , the flexible display device 300 includes a display unit 350a, an adhesive layer 360 , a polarizing plate 370 , a touch screen panel 380 , and a flexible window film 390 , and a flexible window film. 390 may include 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 a substrate and an optical element including an OLED, LED, or LCD element formed on the substrate. The display unit 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 protective film, and an insulating film.

The lower substrate supports the display unit, 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, 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, or a polyacrylate substrate, but is not limited thereto.

A plurality of driving wirings (not shown) and sensor wirings (not shown) intersect to define a plurality of pixel regions in the display region of the lower substrate, and each pixel region includes a thin film transistor and an organic light emitting diode connected to the thin film transistor An organic light emitting diode array can be formed. In the 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 unit may be formed on one side or both sides of the display area.

The thin film transistor controls a current flowing through a semiconductor by applying an electric field perpendicular thereto, and may be formed on a lower substrate. The thin film transistor may include a gate electrode, a gate insulating layer, a semiconductor layer, a source electrode, and a drain electrode. The thin film transistor is an oxide thin film transistor using an oxide such as indium gallium zinc oxide (IGZO), ZnO, or TiO 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, Alternatively, it may be a polycrystalline silicon thin film transistor using polycrystalline silicon as a semiconductor layer.

The planarization layer may cover the thin film transistor and the circuit unit to planarize the upper surface of the thin film transistor and the circuit unit to form an 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 implements a display by emitting light by itself, and may include a first electrode, an organic light emitting layer, and a second electrode stacked in sequence. Adjacent organic light emitting diodes may be separated through an insulating layer. The organic light emitting diode may include a bottom light emitting structure in which light generated from the organic light emitting layer is emitted through a lower substrate or a top light emitting structure in which light generated from the organic light emitting layer is emitted upward.

The protective film covers the organic light emitting diode to protect the organic light emitting diode. The protective film includes inorganic materials such as SiOx, SiNx, SiC, SiON, SiONC and aC (amorphous carbon), (meth)acrylate, epoxy-based polymer, and imide-based polymer. and the like. Specifically, the passivation layer 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 back to FIG. 4 , the adhesive layer 360 adheres the display unit 350a and the polarizing plate 370 , and is formed of a pressure-sensitive adhesive composition including a (meth)acrylate-based resin, a curing agent, an initiator, and a silane coupling agent. can be

The polarizing plate 370 may implement polarization of internal light or prevent reflection of external light to implement a display or increase the contrast ratio of the display. The polarizing plate may be composed of a polarizer alone. Alternatively, the polarizing plate may include a polarizer and a protective film formed on one or both surfaces of the polarizer. Alternatively, the polarizing plate may include a polarizer and a protective coating layer formed on one or both surfaces of the polarizer. As the polarizer, the protective film, and the protective coating layer, conventional ones known to those skilled in the art may be used.

The touch screen panel 380 detects a change in capacitance generated when a human body or a conductor such as a stylus touches the touch screen panel 380 to generate an electrical signal, and the display unit 350a may be driven by this signal. The touch screen panel 380 is formed by patterning a flexible and conductive conductor, and may include a first sensor electrode and a second sensor electrode that is formed between the first sensor electrode and intersects the first sensor electrode. there is. 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 polarizing plate 370 and the touch screen panel 380 and/or between the touch screen panel 380 and the flexible window film 390 , such that a polarizing plate, a touch screen panel, and a flexible The bond between the window films can be strengthened. The pressure-sensitive adhesive layer may be formed of a pressure-sensitive adhesive composition including a (meth)acrylate-based resin, a curing agent, an initiator, and a silane coupling agent. In addition, the adhesive layer may be an adhesive layer including the organic nanoparticles. In addition, although not shown in FIG. 4 , a polarizing plate is further formed under the display unit 350a to realize polarization of internal light.

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

Referring to FIG. 5 , the flexible display device 400 includes a display unit 350a, a touch screen panel 380 , a polarizing plate 370 , and a flexible window film 390 , and the flexible window film 390 is the present invention. It may include a flexible window film according to embodiments of the. The flexible display according to an embodiment of the present invention, except that the touch screen panel 380 is not formed directly on the flexible window film 390 and the touch screen panel 380 is formed under the polarizing plate 370 . substantially identical to the device. Also, at this time, the touch screen panel 380 may be formed together with the display unit 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 is thinner and brighter than the flexible display device according to an embodiment of the present invention, so that visibility may be good. Also, in this case, the touch screen panel 380 may be formed by deposition, but is not limited thereto. Although not shown in FIG. 5 , between the display unit 350a and the touch screen panel 380 and/or between the touch screen panel 380 and the polarizing plate 370 and/or between the polarizing plate 370 and the flexible window film 390 . By further forming an adhesive layer on the surface, the mechanical strength of the display device can be increased. The pressure-sensitive adhesive layer may be formed of a pressure-sensitive adhesive composition including a (meth)acrylate-based resin, a curing agent, an initiator, and a silane coupling agent. In addition, the adhesive layer may be an adhesive layer including the organic nanoparticles. In addition, although not shown in FIG. 5 , a polarizing plate is further formed under the display unit 350a to induce polarization of internal 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 . 6 is a cross-sectional view of a flexible display device according to another embodiment of the present invention. Referring to FIG. 6 , the flexible display device 500 includes a display unit 350b, an adhesive layer 360 , and a flexible window film 390 , and the flexible window film 390 according to embodiments of the present invention It may include a flexible window film. It is substantially the same as the flexible display device according to an embodiment of the present invention, except that the device can be driven only by the display unit 350b and the polarizing plate and the touch screen panel are excluded.

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

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

production example One

A mixture of 3-isocyanatopropyltriethoxysilane (KBE-9007, Shin-Etsu) and 1,4-butanediol (Daejeong Hwageum) in a molar ratio of 2: 1 was placed in a 500 ml 3-neck flask. . To the mixture, 0.2 wt % of a dibutyltindilaurate (DBTDL) catalyst compared to 3-isocyanatopropyltriethoxysilane was added, and stirred at 25° C. for 5 hours to prepare a compound of Formula A below.

<Formula A>

(OEt) ₃ Si-C ₃ H ₆ -NHC(=O)-OC ₄ H ₈ -O-(C=O)NH-C ₃ H ₆ -Si(OEt) ₃

production example 2

A mixture of 3-isocyanatopropyltriethoxysilane (KBE-9007, Shin-Etsu) and triethylene glycol (Daejeong Hwageum) in a molar ratio of 2: 1 was placed in a 500ml 3-neck flask. To the mixture, 0.2% by weight of a dibutyltindilaurate (DBTDL) catalyst compared to 3-isocyanatopropyltriethoxysilane was added and stirred at 25° C. for 5 hours to prepare a compound of Formula B below.

<Formula B>

(OEt) ₃ Si-C ₃ H ₆ -NHC(=O)-O-(CH ₂ CH ₂ O) ₂ -CH ₂ CH ₂ -O-(C=O)NH-C ₃ H ₆ -Si(OEt) ) ₃

Example One

A silicone monomer mixture containing 5 mol% of the compound of Formula A of Preparation Example 1 and 95 mol% of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (Shin-Etsu) was placed in a 500ml 3-neck flask. put To the monomer mixture, 0.5 mol% of KOH relative to the monomer mixture and 100 mol% of water relative to the alkoxy group in the monomer mixture were added, followed by stirring at 25° C. for 2 hours, and stirring at 50° C. for 6 hours. By washing with water, the reaction catalyst and by-products are removed, and the solvent remaining in the vacuum distillation apparatus is removed to remove the silicone resin (EcSiO _3/2 ) _0.95 (O _3/2 Si-C ₃ H ₆ -NHC(=O)-OC ₄ H ₈ -O-(C=O)NH-C ₃ H ₆ -SiO _3/2 ) _0.05 (weight average molecular weight: 15300, by gel permeation chromatography (GPC)) was prepared.

100 parts by weight of the prepared silicone resin, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 20 parts by weight, initiator diphenyliodonium hexafluoroantimonate (DPI-PF6, TCI) ) by adding 2 parts by weight to prepare a composition for a window film. The prepared composition for a window film was bar-coated on a polyimide film having a thickness of 80 μm, dried at 80° C. for 4 minutes, irradiated with UV of 500 mJ/cm ² , and heated at 100° C. for 24 hours, the window coating layer thickness A window film of 10 μm was prepared.

Example 2

In Example 1, a silicone monomer mixture containing 5 mol% of the compound of Formula B of Preparation Example 2 and 95 mol% of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (Shin-Etsu) was used. A window film was prepared in the same manner as in Example 1, except that.

Example 3

In Example 1, the silicone resin ((meth)acrylic Oxy-PrSiO _{3 / 2} ) _0.95 (O _3/2 Si-C ₃ H ₆ -NHC(=O)-OC ₄ H ₈ -O-(C=O)NH-C ₃ H ₆ -SiO _3/2 ) _0.05 was prepared.

A composition for a window film was prepared by adding 100 parts by weight of the prepared silicone resin, 20 parts by weight of a crosslinking agent ethoxylated tetraacrylate (SR499, Sartomer), and 2 parts by weight of an initiator Irgacure-184 (I-184, BASF). . The prepared composition for a window film was bar-coated on a polyimide film having a thickness of 80 μm, dried at 80° C. for 4 minutes, and irradiated with UV of 500 mJ/cm ² to prepare a window film having a window coating layer thickness of 10 μm. .

Example 4

A window film was prepared in the same manner as in Example 3, except that in Example 3, a silicone monomer mixture containing 5 mol% of the compound of Formula B of Preparation Example 2 and 95 mol% of methacryloxypropyltrimethoxysilane was used. did

comparative example One

A window film was prepared in the same manner as in Example 1, except that a silicone monomer mixture containing 100 mol% of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (Shin-Etsu) was used.

comparative example 2

A window film was prepared in the same manner as in Example 3, except that a silicone monomer mixture containing 100 mol% of methacryloxypropyltrimethoxysilane was used.

comparative example 3

Polydimethylsiloxane PDMS having an OH group in Example 1 (DMS-15, Gelest, weight average molecular weight: 1500, no urethane bond) 5 mol%, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane (Shin -Etsu) A window film was prepared in the same manner as in Example 1, except that a silicone monomer mixture containing 95 mol% was used.

The composition of the composition for a window film of Examples and Comparative Examples is shown in Table 1 below.

Example comparative example One 2 3 4 One 2 3 silicone monomer
(mol%)

silicone monomer 1 95 95 - - 100 - 95 silicone monomer 2 - - 95 95 - 100 - Preparation Example 1 5 - 5 - - - - Preparation 2 - 5 - 5 - - - silicone monomer 3 - - - - - - 5 crosslinking agent
(parts by weight) crosslinking agent 1 20 20 - - 20 - 20 Crosslinker 2 - - 20 20 - 20 - initiator
(parts by weight) Initiator 1 2 2 - - 2 - 2 Initiator 2 - - 2 2 - 2 -

* In Table 1, silicone monomer 1: 2-(3,4-epoxycyclohexyl) ethyltriethoxysilane, silicone monomer 2: methacryloxypropyltrimethoxysilane, silicone monomer 3: polydimethylsiloxane PDMS having an OH group; Crosslinking agent 1: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, crosslinking agent 2: ethoxylated tetraacrylate, initiator 1: diphenyliodonium hexafluoroantimonate, initiator 2 : Irgacure-184.

The following physical properties (1) to (4) were measured for the window films prepared in Examples and Comparative Examples, and are shown in Table 2 below.

(1) Pencil hardness: It is measured by the JIS K5400 method using a pencil hardness meter (Heidon) for the coating layer of the window film. When measuring the pencil hardness, Mitsubishi's 6B to 9H pencils were used. The load of the pencil with respect to the coating layer was 1 kg, the angle of drawing a pencil was 45 degrees, and the speed of drawing a pencil was 60 mm/min. If it is evaluated 5 times and scratches occur more than once, the pencil hardness is measured using a pencil of the lower level, and when evaluated 5 times, it is the maximum pencil hardness value when there are no scratches in all 5 times.

(2) Impact resistance (pen-drop test): An adhesive film (thickness: 50 μm, 3M company OCA 8146) was attached to the window films of Examples and Comparative Examples, and the window film was coated with a polyethylene terephthalate (PET) film (thickness: 100). ㎛, Mitsubishi) was fixed so that the coating layer was on top. A specimen was prepared by sequentially placing an aluminum foil and a stainless plate (SUS plate) on the lower surface of the PET film.

Among the specimens, a pen weighing 5.8 g and having a ball size (diameter) of PEN of 0.7 mm was dropped from a predetermined height from the coating layer, and the initial height at which visible marks were made on the surface of the aluminum foil and the coating layer was evaluated. The average value was obtained by repeating 5 times. The higher the initial height, the higher the impact resistance of the window film.

(3) Radius of curvature: Wind the window film (width x length x thickness, 3cm x 15cm x 90㎛, base layer thickness: 80㎛, coating layer thickness: 10㎛) on the JIG for curvature test, and maintain the wound state for more than 5 seconds. Then, it was visually evaluated whether cracks occurred in the film when unwrapped in JIG. The radius of curvature was measured by making the coating layer contact the JIG in the compression direction (in-folding direction), and starting from the maximum radius of the JIG, gradually decreasing the diameter of the JIG. The minimum radius was determined as the radius of curvature. The radius of curvature was measured by making the base layer contact the JIG in the tensile direction (out-folding direction), starting from the maximum radius of the JIG and gradually decreasing the diameter of the JIG. The minimum radius of was determined as the radius of curvature.

(4) Haze: Haze (%) was measured for the window films of Examples and Comparative Examples using NDH2000 manufactured by NIPPON DENSHOKU.

Example comparative example One 2 3 4 One 2 3 pencil hardness 4H 4H 4H 4H 5H 5H 3H impact resistance
(cm) 10 12 5 8 4 One 10 curvature
radius
(mm) Compression direction <1 <1 <1 <1 <1 <1 <1 Tensile direction 1.5 One 2 1.5 8 15 2.5 Haze (%) 0.8 0.9 0.7 0.8 0.8 0.6 3.5

As shown in Table 2, the composition for a window film according to an embodiment of the present invention has excellent pencil hardness and impact resistance, and has a low radius of curvature in both the compression direction and the tensile direction to provide a window film with excellent flexibility and low haze. can be implemented

However, (R ⁴ -[-O-(C=O)NH-R ⁵ -SiO _{3 / 2} ] _n ) in Formula 1 is not included. Comparative Examples 1 and 2 containing the siloxane resin had poor impact resistance and a radius of curvature in the tensile direction. In addition, Comparative Example 3 without a urethane bond cannot be used as a film because the haze is not good.

Simple modifications or changes of the present invention can be easily carried out by those of ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (13)

a siloxane resin, a crosslinking agent and an initiator;
The siloxane resin is a composition for a window film comprising at least one of the following Chemical Formulas 1-1 to 1-6:
<Formula 1-1>
(EcSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-OC ₄ H ₈ -O-(C=O)NH-C ₃ H ₆ -SiO _3/2 ) _z
<Formula 1-2>
(EcSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-O-(CH ₂ CH ₂ O) ₂ -CH ₂ CH ₂ -O-(C=O)NH- C ₃ H ₆ -SiO _3/2 ) _z
<Formula 1-3>
((meth)acryloxy-PrSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-OC ₄ H ₈ -O-(C=O)NH-C ₃ H ₆ - SiO _3/2 ) _z
<Formula 1-4>
((meth)acryloxy-PrSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-O-(CH ₂ CH ₂ O) ₂ -CH ₂ CH ₂ -O-( C=O)NH-C ₃ H ₆ -SiO _3/2 ) _z
<Formula 1-5>
(GpSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-OC ₄ H ₈ -O-(C=O)NH-C ₃ H ₆ -SiO _3/2 ) _z
<Formula 1-6>
(GpSiO _3/2 ) _x (O _3/2 Si-C ₃ H ₆ -NHC(=O)-O-(CH ₂ CH ₂ O) ₂ -CH ₂ CH ₂ -O-(C=O)NH- C ₃ H ₆ -SiO _3/2 ) _z
(In Formulas 1-1 to 1-6,
Ec is a (3,4-epoxycyclohexyl)ethyl group, Gp is a glydoxypropyl group, Pr is a propylene group,
0<x<1, 0<z<1, x+z=1).
According to claim 1, In Chemical Formulas 1-1 to 1-6, 0.80≤x≤0.99, 0.01≤z≤0.20, x+z=1, the composition for a window film.
The method of claim 1, wherein the crosslinking agent comprises at least one of a non-cyclic aliphatic epoxy monomer, a cyclic aliphatic epoxy monomer, an aromatic epoxy monomer, a monomer having a (meth)acryl group, and a monomer having a (meth)acryloxy group. Phosphorus, a composition for a window film.
The composition for a window film according to claim 3, wherein the aromatic epoxy monomer comprises a hydrogenated aromatic epoxy monomer.
A flexible window film comprising a base layer and a coating layer formed on one surface of the base layer, wherein the coating layer is formed of the composition for a window film of any one of claims 1 to 4.
The flexible window film of claim 5 , wherein the base layer comprises a polyimide film.
The flexible window film of claim 5, wherein an adhesive layer is further formed on the other surface of the base layer.
According to claim 5, wherein the base layer comprises a film laminate,
The film laminate is a flexible window film in which two or more films are laminated by an adhesive layer.
The flexible window film according to claim 8, wherein the film laminate is a first film, a second film, and the first film and the second film are laminated by the adhesive layer.
The film according to claim 9, wherein the first film and the second film are each 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. That is, a flexible window film.
The method according to claim 9, wherein the adhesive layer comprises: a monomer mixture for a (meth)acrylic copolymer having a hydroxyl group; initiator; and a composition for an adhesive layer comprising at least one of a macromonomer and organic nanoparticles.
The flexible window film of claim 11 , wherein the organic nanoparticles comprise core-shell particles.
A flexible display device comprising the flexible window film of claim 5 .

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