WO2017030392A1

WO2017030392A1 - Low refractive layer and anti-reflection film comprising same

Info

Publication number: WO2017030392A1
Application number: PCT/KR2016/009111
Authority: WO
Inventors: 김부경; 장영래; 장석훈; 허은규; 변진석
Original assignee: 주식회사 엘지화학
Priority date: 2015-08-18
Filing date: 2016-08-18
Publication date: 2017-02-23

Abstract

The present invention relates to a low refractive layer and an anti-reflection film comprising same. The low refractive layer can exhibit both excellent optical properties, i.e. low reflectance and high light transmittance, and excellent mechanical properties, such as high abrasion resistance and scratch resistance, while having no adverse effect on the color of a polymer resin forming the low refractive layer. In particular, the low refractive layer can maintain said excellent physical properties, even after alkali treatment, due to excellent alkali resistance. Accordingly, in the case of being introduced to a display device, the low refractive layer can simplify the production process and is expected to significantly increase the production rate and output.

Description

【Specification】

[Name of invention]

Low refractive layer and antireflection film comprising the same

Technical Field

Cross Citation with Related Application (s)

This application claims the benefit of priority based on Korean Patent Application No. 10-2015-0116260 dated August 18, 2015 and Korean Patent Application No. 10-2016-0104409 dated August 17, 2016. All content disclosed in the literature is included as part of this specification.

The present invention relates to a low refractive index layer and an antireflection film including the low refractive index layer and a hard coating layer.

Background Art

In general, a flat panel display device such as a PDP or LCD is equipped with an anti-reflection film for minimizing reflection of light incident from the outside.

As a method for minimizing the reflection of light, a method of dispersing a filler of inorganic fine particles in a resin is coated on a base film and imparts irregularities (ant i-glare: AG coating); There are a method of forming a plurality of layers having different refractive indices on a base film to use interference of light (ant i-ref lect ion: AR coating), or a method of using them in common.

Among them, in the case of the AG coating, the absolute amount of reflected light is equivalent to that of a general hard coating, but a low reflection effect can be obtained by reducing the amount of light entering the eye by using light scattering through unevenness. However, since the AG coating has poor screen clarity due to surface irregularities, much research has recently been conducted on AR coatings.

As the film using the AR coating, a multilayer structure in which a hard coating layer (high refractive index layer), a low reflection coating layer, and the like are laminated on a base film is commercialized. However, the method of forming a plurality of layers as described above has a disadvantage in that scratch resistance is inferior due to weak adhesion between the layers (interfacial adhesion) as a separate process of forming each layer.

This reduces the amount of absolute reflection of light incident from the outside, Many studies have been conducted to improve scratch resistance, but the degree of improvement in physical properties is insufficient. In addition, a method of adding an inorganic additive or the like to the polymer film applied to the antireflection film to increase scratch resistance is known. According to this, the alkali resistance of the polymer film is greatly reduced, and thus it is not applicable to the manufacturing process of the polarizing plate. There was a limit to inadequacy.

[Content of invention]

[Problem to solve]

The present invention provides a low refractive index layer that can exhibit excellent optical and mechanical properties.

In addition, the present invention provides an antireflection film including the low refractive layer.

[Measures of problem]

Hereinafter, a low refractive index layer and an antireflection film including the same according to a specific embodiment of the present invention will be described.

According to one embodiment of the invention, there is provided a low refractive layer that satisfies the following formula (1). [Equation 1]

0.5> Ab ^* = \ b-b ^* is

In Equation 1,

b ^* ₀ is the b ^* value of the L ^* a ^* b ^* color coordinate system as determined by the International Lighting Commission of the Low Refractive Layer,

I is the low refractive index layer to an aqueous solution of sodium hydroxide of 10 parts by weight and heated to 30 ^° C>

After immersion for 2 minutes, washed with water and wiped the water, immersed in 10% by weight aqueous sodium hydroxide solution heated to 55 ^° C for 30 seconds, washed with water and wiped to measure b ^* ₀ on the prepared film Measured as in the method, L ^* a ^* b ^* b ^* value of the color coordinate system. As used herein, the term low refractive index layer may mean a layer having a low refractive index, for example, a layer exhibiting a refractive index of about 1.2 to 1.6. The low refractive index layer according to the embodiment has excellent mechanical properties such as scratch resistance and optical properties such as reflectance and color for the visible light region. Accordingly, the low refractive index layer can be used in a display device to remarkably improve the glare caused by light incident from the outside of the device without degrading the image quality, and can effectively protect the surface of the device from external stratified black stimulation. have. In addition, the low refractive layer has a very small change in physical properties even when exposed to alkali. Due to this high alkali resistance, the low refractive index layer can omit the attachment and desorption process of the protective film which is essentially performed to protect the low refractive index during the manufacturing process of the display device, thereby eliminating the production process of the display device Simplify and lower production costs. In particular, the low refractive index layer is also excellent in alkali resistance at high temperature is expected to be able to greatly improve the production speed and productivity without reducing the quality of the device by adjusting the manufacturing conditions of the manufacturing process of the display device to more severe conditions.

More specifically, the low refractive layer may satisfy the above formula (1). In Equation 1, b ^* ₀ is a value capable of evaluating the initial color of the low refractive index layer, b is a value capable of evaluating the color of the alkali-treated low refractive index layer. At this time, the low refractive layer is treated with alkali twice, in particular, the second alkali treatment is performed by a high temperature aqueous sodium hydroxide solution. Thereby, alkali resistance at the high temperature of the low refractive layer can be evaluated through the degree of color change of the low refractive layer before and after the alkali treatment of the formula (1). The alkali treatment conditions are the same as those described in Equation 1, and for the details related to the alkali treatment, reference may be made to the experimental examples described later. Further, detailed examples related to the evaluation method of the b ^* value of the L ^* a ^* b ^* color coordinate system for the low refractive layer before and after the alkali treatment may be referred to the experimental example described later.

The low refractive index layer according to an embodiment may have a color change degree (Ab ^* ) of 0.5 or less, 0.45 or less, or 0.4 or less before and after alkali treatment due to excellent alkali resistance. Since the low refractive index layer may have no color change even after high temperature alkali treatment, Ab ^* of Equation 1 may be zero.

In order to exhibit low reflectance in the visible light region or to improve scratch resistance, the conventional low refractive layer has been added with an inorganic layer agent. However, these inorganic fillers greatly reduced the alkali resistance of the low refractive index layer, making it difficult to apply the low refractive index layer to the manufacturing process of the display device which essentially involves an alkali treatment process, and color the low refractive layer to image quality of the display device. There was a problem that adversely affects.

However, the low refractive index layer according to the embodiment has excellent scratch resistance and no color change or minimizes color change of the polymer resin included in the low refractive layer. Properties such as alkali resistance can be exhibited. For example, the b ^* value (b ^* ₀ value of Equation 1) before the alkali treatment of the low refractive layer may be 1 to -8 or 1 to -5.

In the I / a ^* b ^* color coordinate system, a value of 1 represents a color biased to yellow if it is positive, and a color biased to blue if negative. Accordingly, the low refractive index layer according to the embodiment may exhibit the color coordinate values as described above, thereby effectively preventing the glare while transmitting the image as it is without changing the quality of the display device image.

In addition, the low refractive index layer according to the embodiment exhibits excellent alkali resistance as described above, and has a characteristic of almost no color change even when exposed to high temperature alkali. As an example, the b ^* value (1A value of Equation 1) after alkali treatment of the low refractive index layer may be 1.5 to -8.5, 1 to -8, 0 to -8 or 1.5 to -5.5. On the other hand, the low refractive index layer according to the embodiment may satisfy the following formula 2 due to the excellent alkali resistance.

[Equation 2]

30%> AS = [(So-S ^ / So] X 100

In Equation 2,

So is the maximum load that does not cause scratch when the steel wool of # 0000 grade is loaded and reciprocated 10 times at the speed of 24rpm and rubbed the surface of the low refractive layer.

¾ immersed the low refractive layer in 10% aqueous sodium hydroxide solution heated to 30 ^° C for 2 minutes, washed with water and wiped dry, and then 30 in 10 weight percent sodium hydroxide aqueous solution heated to 55 ^° C After immersion for a second, the maximum load at which no scratches were generated as in the method of measuring S ₀ on the film prepared by washing with water and wiping off the moisture.

The unit of the load of Equation 2 is g / (2 * 2 cm ² ), which means the weight (g) per area (2 * 2 cm ² ) of 2 cm horizontal, 2 cm vertical.

In Equation 2, So is a value that can evaluate the initial scratch resistance of the low refractive index layer, ^ is a value that can evaluate the scratch resistance of the alkali-treated low refractive layer. At this time, the alkali treatment conditions are the same as in Equation 1, the scratch resistance to the low refractive layer before and after the alkali treatment can be evaluated as described in Equation 2, the details of the scratch resistance evaluation method will be described later in the experimental example Can refer to have.

The low refractive index layer according to the embodiment may have a change rate (AS) of scratch resistance before and after alkali treatment of Formula 2 due to excellent alkali resistance of 30% or less, 25% or less, 20% or less or 15% or less. In addition, since the low refractive index layer may exhibit unchanged scratch resistance even after high-temperature alkali treatment, AS of Formula 2 may be.

On the other hand, as described above, the low refractive layer has excellent mechanical properties such as scratch resistance. For example, the scratch resistance (S ₀ value in Equation 2) before the alkali treatment of the low refractive index layer may be about 250 to 800 g / (2 * 2cm ² ) black about 300 to 800 g / (2 * 2cm ² ). . In addition, the low refractive layer may exhibit excellent scratch resistance even after alkali treatment due to the excellent alkali resistance. For example, the scratch resistance (value of Equation 2) after alkali treatment of the low refractive index layer may be about 200 to 800 g / (2 * 2 cm ² ) or about 230 to 800 g / (2 * 2 cm ² ).

The low refractive index layer according to the embodiment may exhibit the minimum reflectance in the visible light region together with the excellent optical and mechanical properties described above. More specifically, the low refractive index layer exhibits a minimum reflectance in a wavelength region of about 480 to 680 nm or a wavelength region of about 500 to 580 nm, thereby effectively preventing glare of the display device.

In addition, the low refractive layer according to the embodiment may exhibit a very low reflectance in the visible light region. More specifically, the low refractive index layer may have an average reflectance of 0.9 to 2.5%, 0.9 to 2.2%, 0.9 to 2.0%, 0.9 to 1.5¾> black and 1 to 1.3% for light in the wavelength range of 380 to 780 nm. . Accordingly, when the low refractive index layer is introduced into the display device, glare caused by light incident from the outside may be prevented.

The average reflectance and color coordinate values of the low refractive index layer may be measured using a spectrophotometer. Specifically, at room temperature, the sampling interval 1 nm (preferably 2 nm or less, but can also be adjusted to 5 nm), t ime constant 0.1 sec, slit width 20 nm, fixing the measurement conditions at medium scanning speed, The opposite side of the surface to be irradiated with light of both sides is darkened so as not to transmit light, and the reflectance and color coordinate values may be measured by irradiating the other surface with light in a wavelength region of 380 nm to 780 nm. At this time, the low refractive index layer is a base film; Or on a base film as mentioned later If it is formed in the formed hard coating layer, the low refractive black of the base film may darken the surface on which the hard coating layer is not formed so that light cannot be transmitted. For example, the darkening may be performed by attaching a black tape to a corresponding surface.

In addition, when the low refractive layer has a flat surface free from irregularities, the light is irradiated ^at an angle of incidence of 5 ^° and the light reflected ^at a angle of reflection of 5 ^° is provided to provide a standard sample material (BaS0 ₄ and 95% A1 mirror, provided by Shimadzu. Based on the measured value of), the reflectance according to the wavelength of the low refractive layer is measured (measure mode). The average reflectance and color coordinate values may be derived from the reflectance through the UV-240 IPC color analyzer program.

On the other hand, when the low refractive layer has a surface with irregularities, the light is incident perpendicularly to the low refractive layer and scattered in all directions to measure the reflected light to measure the standard sample material (BaS0 ₄ , provided by Shimadzu). Based on this, the reflectance according to the wavelength of the low refractive layer is measured (10 T mode). The average reflectance and color coordinate values may be derived from the reflectance through the UV-2401PC color analyzer program. As described above, the low refractive index layer according to the embodiment, which may exhibit excellent optical and mechanical properties, may include a photopolymerizable compound and a polysilsesquioxane substituted with at least one semi-ungsung functional group (polysi sesquioxane), -0_CF ₂ CF _It may include a photocured obtained by photocuring a photocurable coating composition comprising a fluorine-based compound, ₂ -0-CF ₃ , including inorganic particles and a photopolymerization initiator.

In the present specification, a photopolymerizable compound is collectively referred to as a compound causing polymerization reaction when light is irradiated, for example, visible light or ultraviolet light.

The photocurable coating composition may include a monomer or oligomer comprising a (meth) acryloyl group or a vinyl group as the photopolymerizable compound. The monomer or oligomer may include one or more, two or more or three or more (meth) acryloyl groups or vinyl groups. In the present specification, (meth) acryl [(meth) acryl] is meant to include both acryl and methacryl.

Specific examples of the monomer or oligomer containing the (meth) acryloyl group include pentaerythritol tri (meth) acrylate, pentaerythrite tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Nucleate (meth) acrylate, dipentaerythrate, hepta (meth) acrylate, trimethyl-propane tri (meth) acrylate, trimethylolpropane polyhydroxy tri (meth) acrylate, ethylene glycol di (Meth) acrylate, butanediol di (meth) acrylate, ethylnuclear (meth) acrylate, butyl (meth) acrylate or two or more kinds thereof, or urethane-modified acrylate oligomers, epoxide acrylate oligomers , Ether acrylate oligomers, dendritic acrylate oligomers or two or more kinds thereof.

And specific examples of the monomer or oligomer containing the vinyl group include divinylbenzene, styrene, paramethyl styrene or oligomers obtained by combining one or more of them. The molecular weight of the oligomer in the above can be adjusted to 1, 000 to 10,000g / niol.

The content of the photopolymerizable compound in the photocurable coating composition is 20% by weight to 80% by weight, 30% by weight to 70% by weight, based on the solid content of the photocurable coating composition in consideration of the mechanical properties of the low refractive layer to be finally produced. Or 30% to 65% by weight.

Solid content of the photocurable coating composition means only a solid component excluding components of the photocurable coating composition thickening liquid, for example, an organic solvent or the like that may be optionally included as described below.

The photocurable coating composition includes polysilsesquioxane in which one or more semi-functional functional groups are substituted, and can realize low reflectivity and high light transmittance without coloring, improve alkali resistance, and at the same time, excellent wear resistance or It is possible to provide a low refractive index layer that can secure scratch resistance.

The polysilsesquioxane substituted with at least one semi-functional functional group may be included in an amount of 0.5 to 25 parts by weight, 1 to 20 parts by weight, 1.5 to 19 parts by weight, or 2 to 15 parts by weight with respect to 100 parts by weight of the photopolymerizable compound. In addition, the content of the polysilsesquioxane substituted with at least one semi-cyclic functional group in the photocurable coating composition is 1% by weight to 25% by weight, 1% by weight to 20% by weight, based on the solid content of the photocurable coating composition. », 1% by weight to 15% by weight black may be adjusted to 1% by weight to 10% by weight. If the content of the polysilsesquioxane substituted with at least one semi-functional functional group is less than the above-mentioned range, the alkali resistance or scratch resistance of the coating film or the polymer resin formed during photocuring of the photocurable coating composition is sufficiently secured. It can be difficult to do. On the other hand, when the content of the polysilsesquioxane substituted with at least one semi-functional functional group exceeds the above-mentioned range, the transparency of the low refractive layer prepared from the photocurable coating composition may be lowered, and scratch resistance is rather deteriorated. Can be.

The semi-functional groups which may be substituted in the polysilsesquioxane include alcohols, amines, carboxylic acids, epoxides, imides, (meth) acrylates, nitriles, norbornenes, olefins [al ly, cyclo] Alkenyl (cyc loalkenyl) or vinyldimethylsilyl, etc.], polyethyleneglycol, thiol, and a vinyl group may include one or more functional groups selected from the group, and may preferably include an epoxide or (meth) acrylate. have.

More specifically, when the semi-functional group is an epoxide, 2- [3,4-epoxycyclonuclear] ethyl group or 3-glycidoxypropyl group may be introduced as the semi-functional group. In the case of (meth) acrylate, a (meth) acryloyloxyalkyl group (in this case, the alkyl group may have 1 to 6 carbon atoms) or the like may be introduced as a semi-active functional group.

In the present specification, even though the polysilsesquioxane employs the same functional group as the photopolymerizable compound as a semi-functional functional group, the polysilsesquioxane having a siloxane bond (-Si-0-) as a skeleton is not included in the photopolymerizable compound. It is prescribed. On the other hand, the polysilsesquioxane substituted with one or more of the semi-cyclic functional group is a linear or branched alkyl group of 1 to 30 carbon atoms, a cycloalkyl group of 6 to 30 carbon atoms and an aryl group of 6 to 30 carbon atoms in addition to the above-mentioned semi-functional functional group It may be further substituted with one or more non-banung functional groups selected from the group consisting of. As described above, the surface of the polysilsesquioxane is substituted with a semi-active functional group and a non-cyclic functional group, so that the siloxane bond (-Si-0-) is in the molecule in the polysilsesquioxane in which the semi-functional functional group is substituted with at least one. While not being exposed to the outside while being located in the alkali resistance of the coating film or polymer resin formed during the photocuring of the photocurable coating composition can be further improved. In particular, the non-banung functional group introduced into the polysilsesquioxane together with the semi-aromatic functional group is a linear or branched alkyl group having 6 or more carbon atoms; Linear or branched alkyl groups having 6 to 30 carbon atoms; Or in the case of a C6-C30 cycloalkyl group, the alkali resistance of a low refractive layer can be improved more.

The polysilsesquioxane may be represented as (! ^ ^ ^; ^ (Where n is 4 to 30 or 8 to 20, R is each independently a semi-functional group; or a straight chain having 1 to 30 carbon atoms or A non-acyclic functional group selected from the group consisting of a branched alkyl group, a cycloalkyl group having 6 to 30 carbon atoms, and an aryl group having 6 to 30 carbon atoms), a random structure, a ladder, a cage, and a partial cage. It can have

Among them, in order to further improve the above-described characteristics, a polysilsesquioxane in which the semi-maleic functional group is substituted with one or more, polyhedral oligomeric yarn substituted with one or more semi-maleic functional groups and having a cage structure Sesquioxane (Polyhedral 01 igomeric Si l sesquioxane) can be used.

More specifically, the polyhedral oligomeric silsesquioxane may comprise 8 to 20 silicon in the molecule.

Examples of polyhedral oligomer silsesquioxanes (Posihedral 01 igomeric Si l sesquioxane, POSS), which are substituted with one or more semi-active functional groups and have a cage structure, include TMP Diol Isobutyl POSS, Cyclohexanediol Isobutyl POSS, 1,2 POSS with one or more alcohol substitutions, such as Propanediol Isobutyl POSS, Oct a (3 hydroxy ᅳ 3 methylbutyldimethyl sioxy) POSS; POSS substituted with one or more amines such as Ami nopropyl Isobutyl POSS, Aminopropyl Isooctyl POSS, Aminoethylaminopropyl Isobutyl POSS, N ᅳ Phenyl ami nopropyl POSS, N ᅳ Methyl ami nopropyl Isobutyl POSS, OctaAmmonium POSS, Am inophenyl Cyclohexyl POSS, Aminophenyl Isobutyl POSS; POSS in which at least one carboxylic acid is substituted, such as Maleamic Acid-Cyclohexyl POSS, Maleamic Acid-Isobutyl POSS, Oct a Maleamic Ac POSS; POSS substituted with at least one epoxide such as EpoxyCyclohexyl Isobutyl POSS, Epoxycyclohexyl POSS, Glycidyl POSS, GlycidylEthyl POSS, Glycidyl Isobutyl POSS, Glycidyl Isooctyl POSS; POSS in which at least one imide such as POSS Maleimide Cyclohexyl and POSS Maleimide Isobutyl is substituted; Acrylolsobutyl POSS, (Meth) acryl Isobutyl POSS, (Meth) acrylate Cyclohexyl POSS, (Meth) acrylate Isobutyl POSS, (Meth) acrylate Ethyl POSS, (Meth) acrylEthyl POSS, POSS in which one or more (meth) acrylates are substituted, such as (Meth) acrylate Isooctyl POSS, (Meth) acryl Isooctyl POSS, (Meth) acrylPhenyl POSS, (Meth) acryl POSS, and Acrylo POSS; P0SS in which at least one nitrile group such as Cyanopropyl lsobutyl POSS is substituted; POSS in which at least one norbornene group is substituted, such as NorbornenylethylEthyl POSS, Norbornenylethyl Isobutyl POSS, Nor bornenyl ethyl DiSi lanoIsobutyl POSS, and Tr snor bornenyl Isobutyl POSS; POSS substituted with one or more vinyl groups such as Al lyl Isobutyl POSS, MonoVinyl Isobutyl POSS, OctaCyclohexenyldimethyl silyl POSS, OctaVinyldimethyl silyl POSS, OctaVinyl POSS; POSS in which at least one olefin such as Al lyl Isobutyl POSS, MonoVinyl Isobutyl POSS, OctaCyclohexenyldimethyl silyl POSS, OctaVinyldimethyl siyl POSS, OctaVinyl POSS is substituted; POSS substituted with PEG of 5 to 30 carbon atoms; Or POSS in which one or more thiol groups such as Mercaptopropyl Isobutyl POSS or Mercaptopropyl Isooctyl POSS are substituted; Etc. can be mentioned.

In addition, at least one or more of the silicon of the polyhedral oligomeric silsesquioxane may be introduced with a semi-functional functional group, and the above-described non-acyclic functional group may be substituted with the silicone having no semi-functional functional group introduced therein.

When a semi-functional group is introduced into at least one of the polyhedral oligomeric silsesquioxane silicones, the mechanical properties of the coating film or the polymer resin formed during photocuring of the photocurable coating composition may be greatly improved. In addition, when non-acyclic functional groups are introduced into the remaining silicon, molecular structural steric hindrance (Ster i c hinderance) may occur, thereby greatly reducing the possibility of exposing the siloxane bond (-Si-0-) to the outside. Accordingly, the alkali resistance of the coating film or the polymer resin formed during photocuring of the photocurable coating composition can be greatly improved.

More specifically, when the reactive functional group and the non-banung functional group are substituted together in the polysilsesquioxane, the molar ratio of the semi-ung functional group to the non-banung functional group substituted in the polysilsesquioxane Molar number of the male functional group) may be 0.20 or more or 0.30 or more, and may also be 0.20 to 6.00, 0.30 to 4.00 or 0.40 to 3.00.

When the ratio between the semi- and semi-cyclic functional groups substituted by the polysilsesquioxane is within the above range, steric hindrance in the polysilsesquioxane molecule may be maximized, and thus, siloxane bond (-Si-0-) Will be exposed outside Concerns are significantly reduced so that the mechanical properties and alkali resistance of the coating film or polymer resin formed during photocuring of the photocurable coating composition can be greatly improved. The photocurable coating composition includes a fluorine-based compound including -0—CF ₂ CF ₂ -0-CF ₃ .

In the present specification, the fluorine-based compound refers to a compound having a weight average molecular weight of 2,000 g / mol or more and substituted with fluorine, and such a compound is not included in the definition of the photopolymerizable compound.

In particular, the fluorine-based compound includes -0-CF ₂ CF ₂ -0-CF ₃ , the low refractive layer prepared from the photocurable coating composition may have a lower reflectance and improved light transmittance and also improved alkali resistance and It can exhibit scratch resistance. The fluorine-based compound is 0-with _{_{-0-CF 2 CF 2 -0-}} CF 3 (CF 2) n -0- ( wherein n is an integer from 1 to 3), and -0-CF _₂ CF ₂ CF ₃ Including the physical properties can be further improved.

At least one photoreactive functional group is introduced into the fluorine-based compound, and the photoreactive functional group means a functional group capable of participating in the polymerization reaction by irradiation of light, for example, visible light or ultraviolet radiation. The photoreactive functional group may include various functional groups known to be able to participate in the polymerization reaction by irradiation of light, and specific examples thereof include (meth) acryloyl groups, epoxy groups, vinyl (vinyl) groups, or merapto. And the like can be mentioned.

The fluorine-based compound may have a fluorine content of 1% by weight to 25% by weight. If the content of fluorine in the fluorine-based compound is less than the above range, it may be difficult to sufficiently secure physical properties such as alkali resistance because the fluorine component may not be arranged on the surface of the final resultant obtained from the photocurable coating composition. In addition, when the content of fluorine in the fluorine-based compound exceeds the above range, the surface properties of the final resultant obtained from the photocurable coating composition may be lowered or defects may be increased during the post-process to obtain the final resultant.

The fluorine compound is silicon; Or the side chain black derived from a silicon compound may further contain a repeating unit. When the fluorine-based compound contains a side chain or repeating unit derived from silicon or a silicon compound, the content of silicon is relative to the fluorine-based compound. 0.1 weight to 20 weight ¾>. Silicon contained in the fluorine-based compound may serve to prevent haze from occurring in the low refractive layer obtained from the photocurable coating composition of the embodiment, thereby increasing transparency. On the other hand, when the content of silicon in the fluorine-based compound exceeds the above range, the alkali resistance of the low refractive layer obtained from the photocurable coating composition may be lowered.

The fluorine-based compound may have a weight average molecular weight of 2,000 to 200, 000 g / m. If the weight average molecular weight of the fluorine-based compound is too small, the low refractive layer obtained from the photocurable coating composition may not have layered alkali resistance. In addition, when the weight average molecular weight of the fluorine-based compound is too large, the low refractive index layer obtained from the photocurable coating composition may not have a layered durability or scratch resistance. As used herein, the weight average molecular weight means a conversion value for standard polystyrene measured by GPCX Gel Permeat ion Chromatograph.

Specifically, the fluorine-based compound is i) an aliphatic compound or an aliphatic ring compound substituted with one or more photoreactive functional groups, at least one hydrogen is substituted with fluorine; ii) silicon-based compounds in which at least one carbon of the aliphatic compound or aliphatic ring compound is substituted with silicon; Hi) a siloxane compound in which at least one carbon of the aliphatic compound or aliphatic ring compound is substituted with silicon and at least one -c¾- is substituted with oxygen; iv) a fluoropolyether wherein at least one -CH ₂ -of said aliphatic compound or aliphatic ring compound is substituted with oxygen; Or a combination of two or more thereof or a copolymer.

In order for the low refractive index layer to exhibit high alkali resistance to satisfy Equation 1 above, a sufficient amount of fluorine should be distributed on the surface of the low refractive layer so that the alkaline solution does not penetrate or be absorbed into the low refractive layer. Even if the alkaline solution penetrates or is absorbed into the layer, the crosslinking density must be high to withstand the alkaline solution.

The cured product of the bloso-based compound is distributed on the surface of the low refractive layer of the present invention, and even if the low refractive layer is treated with alkali, it is possible to prevent the alkaline solution from penetrating into or absorbing into the low refractive layer. However, since the fluorine-based compound has a higher molecular weight than the above-mentioned photopolymerizable compound and has a smaller amount of photoreactive functional groups for the same volume or weight, the content of the photopolymerizable compound is higher. When it decreases and the content of a fluorine compound increases, the crosslinking density of a low refractive layer tends to fall.

Therefore, when an excessive amount of hardened | cured material of the said fluorine-type compound exists from the surface to the inside of a low refractive layer, the crosslinking density of a low refractive layer will fall and it will be hard to show the outstanding alkali resistance.

In order for the low refractive index layer to exhibit high temperature alkali resistance enough to satisfy the above formula 1, the cured product of the fluorine-based compound should exist mostly on the surface of the low refractive layer. It is important to control the content of the fluorine-based compound in the photocurable coating composition in order for the cured product of the fluorine-based compound to exist mostly on the surface of the low refractive index layer.

Specifically, the photocurable coating composition may contain 1 to 75 parts by weight, 1 to 50 parts by weight, 1 to 30 parts by weight, 1 to 20 parts by weight or 1 to 15 parts by weight with respect to 100 parts by weight of the photopolymerizable compound. It may include. In addition, the content of the fluorine-based compound in the photocurable coating composition is 0.5% by weight to 50% by weight, 0.5% by weight to 30% by weight, 0.5% by weight to 20% by weight or 1% by weight relative to the solid content of the photocurable coating composition. To 15% by weight.

When the fluorine-based compound is added in excess of the photopolymerizable compound, the coating property of the photocurable coating composition is lowered or the crosslinking density of the low refractive layer obtained from the photocurable coating composition is lowered, thereby providing sufficient alkali resistance, durability, and scratch resistance. Or the like. In addition, if the amount of the fluorine-based compound is too small compared to the photopolymerizable compound, the fluorine in a layered content is not distributed on the surface of the low refractive layer obtained from the photocurable coating composition, the low refractive layer may not have sufficient alkali resistance. .

On the other hand, the photocurable coating composition includes inorganic particles having a diameter in nanometer or micrometer units.

Specifically, the inorganic particles may be hollow silica particles having a number average particle diameter of 10 to 100 nm. The hollow silica particles are silica particles derived from silicon compounds or organosilicon compounds, and mean silica particles having empty spaces on and / or inside the particles. The hollow silica particles have a lower refraction than the hollow particles to provide excellent antireflection properties. Can be represented.

The inorganic particles may have a number average particle diameter of 10 to 100 nm, 20 to 70 nm, or 30 to 70 nm, and the shape of the particles is preferably spherical, but may be amorphous.

In addition, as the inorganic particles, those whose surfaces are coated with a fluorine-based compound may be used alone, or may be used in combination with inorganic particles whose surfaces are not coated with the fluorine-based compound. Coating the surface of the inorganic particles with a fluorine-based compound may lower the surface energy, and more uniform distribution of the inorganic particles in the photocurable coating composition. Accordingly, the film obtained from the photocurable coating composition containing such inorganic particles may exhibit more improved durability or scratch resistance.

Particle coating methods or polymerization methods commonly known as coating the fluorine-based compound on the surface of the inorganic particles may be used without particular limitation. As a non-limiting example, a method in which the inorganic particles and the fluorine compound are sol-gel reacted in the presence of water and a catalyst to bind the fluorine compound to the surface of the inorganic particle through hydrolysis and condensation reaction may be used.

In addition, the inorganic particles may be included in the composition in the form of a colloid dispersed in a predetermined dispersion medium. The colloidal phase including the inorganic particles may include an organic solvent as a dispersion medium.

The solid content of the inorganic particles in the colloidal phase of the inorganic particles may be determined in consideration of the content range of the inorganic particles in the photocurable coating composition or the viscosity of the photocurable coating composition. For example, the solid content of the inorganic particles in the colloidal phase may be 5% by weight to 60% by weight.

Herein, examples of the organic solvent in the dispersion medium include alcohols such as methanol, isopropyl alcohol, ethylene glycol and butanol; Ketones such as methyl ethyl ketone and methyl isobutyl ketone; Aromatic hydrocarbons such as toluene and xylene; Dimethylformamide. Amides such as dimethylacetamide and N-methylpyridone; Esters such as ethyl acetate, butyl acetate and gamma butyrolactone; Ethers such as tetrahydrofuran and 1,4-dioxane; Or combinations thereof.

The photocurable coating composition is based on 100 parts by weight of the photopolymerizable compound The inorganic particles may comprise 10 to 320 parts by weight, 20 to 200 parts by weight or 30 to 200 parts by weight. In addition, the content of the inorganic particles in the photocurable coating composition may be adjusted to 10% by weight to 80% by weight, 20% by weight to 70% by weight or 20% by weight to 60% by weight with respect to the solid content of the photocurable coating composition. Can be. If the inorganic particles are added in an excessive amount, scratch resistance or abrasion resistance of the coating film may decrease due to a decrease in the content of the polymer resin.

The photopolymerization initiator may be used without particular limitation as long as it is a compound known to be used in the photocurable coating composition, and specifically, a benzophenone compound, acetophenone compound, biimidazole compound, triazine compound, oxime compound, or the like. Two or more kinds thereof may be used.

For 100 parts by weight of the photopolymerizable compound, the photopolymerization initiator may be used in an amount of 1 to 100 parts by weight, 1 to 50 parts by weight, and 1 to 20 parts by weight of black silver. In addition, the content of the photopolymerization initiator in the photocurable coating composition is 0.1% by weight to 15% by weight, 1% by weight to 10% by weight or 3% by weight to 7% by weight relative to the solids of the photocurable coating composition. Can be adjusted.

If the amount of the photopolymerization initiator is too small, an uncured material remaining in the photocuring step of the photocurable coating composition may occur. If the amount of the photopolymerization initiator is too large, the non-aqueous initiator may remain as an impurity or have a low crosslinking density, thereby lowering mechanical properties or reflectance of the film.

Meanwhile, the photocurable coating composition may further include an organic solvent. Non-limiting examples of the organic solvents include ketones, alcohols, acetates and ethers, or combinations of two or more thereof. Specific examples of such organic solvents include ketones such as methyl ethyl ketone, methyl isobutyl ketone, acetylacetone or isobutyl ketone; Alcohols such as methanol, ethane, n-propane, i so-propanol, n-butane, i so-butanol, or t-butanol; Acetates such as ethyl acetate, i-propyl acetate, or polyethylene glycol monomethyl ether acetate; Ethers such as tetrahydrofuran or propylene glycol monomethyl ether; Or two or more kinds thereof.

The organic solvent is a component of the photocurable coating composition It may be included in the photocurable coating composition as it is added at the time of mixing or the components are added in a dispersed or mixed state in an organic solvent. When the content of the organic solvent in the photocurable coating composition is too small, a defect may occur such that the flowability of the photocurable coating composition is lowered, resulting in streaks in the final manufactured film. In addition, when the excessive amount of the organic solvent is added, the solid content is lowered, coating and film formation are not divided, the physical properties and surface properties of the film may be lowered, and defects may occur in the drying and curing process. Accordingly, the photocurable coating composition may include an organic solvent such that the concentration of the total solids of the components included is from 1 to 50 wt%, or from 2 to 20 wt%.

Such photocurable coating compositions may be applied and photocured according to methods known in the art to provide the above-described low refractive layer.

First, the photocurable coating composition may be applied on a predetermined substrate. At this time, the specific type or thickness of the substrate is not particularly limited, and the substrate known to be used for the manufacture of the low refractive layer may be used without particular limitation.

The photocurable coating composition may be applied using a method and apparatus known in the art, for example, bar coating method such as Meyer bar, gravure coating method, 2 roll l reverse coating method, vacuum s It can be applied by lot die coating or 2 roll coating.

The low refractive layer may have a thickness of lnm to 300nm or 50nm to 200nm. Accordingly, the thickness of the photocurable coating composition applied on the predetermined substrate may be adjusted to about lnm to 300ran, or 50nm to 200ηιη.

After applying the photocurable coating composition on the substrate as described above, the photocurable coating composition may be photocured by irradiating ultraviolet or visible light in the wavelength range of 200 to 400nm. At this time, the exposure amount of the irradiated light may be adjusted in the range of 100 to 4, 000 mJ / cm ² , the exposure time may be appropriately adjusted according to the exposure apparatus, the wavelength of the irradiation light or the exposure amount used.

The photocuring step may be performed under a nitrogen atmosphere. Accordingly, nitrogen purging may be further performed before or during the photocuring step. The low refractive index layer prepared from the photocurable coating composition as described above is a photopolymerizable compound, polysilsesquioxane substituted with at least one reactive functional group, and -0-CF ₂ CF ₂ -0-CF ₃ It may include a polymer resin comprising a cross-linked polymer between fluorine-based compounds and inorganic particles dispersed in the polymer resin.

However, the low refractive index layer of the present invention is not formed only by the above-described components and compositions, and may be formed with various components and compositions with reference to the above contents if the formula 1 is satisfied.

On the other hand, according to another embodiment of the invention, the low refractive layer; And a hard coat layer formed on one surface of the low refractive layer. Since the low refractive index layer has been described in detail above, a detailed description thereof will be omitted.

As the hard coating layer, a commonly known hard coating layer may be employed without particular limitation.

For example, the hard coating layer is a photocurable resin and a weight average molecular weight

Binder resin containing a (co) polymer (hereinafter referred to as a high molecular weight (co) polymer) of 10, 000 g / mol or more; And it may include organic or inorganic fine particles dispersed in the binder resin. As used herein, (co) polymer is meant to include both co-polymers and homo-polymers.

The high molecular weight (co) polymer may include at least one polymer selected from the group consisting of cellulose-based polymers, acrylic polymers, styrene-based polymers, epoxide-based polymers, nylon-based polymers, urethane-based polymers, and polyolefin-based polymers. Can be.

The photocurable resin included in the hard coating layer is a polymer of a photopolymerizable compound that may cause polymerization reaction when light such as ultraviolet rays is irradiated, and may be one commonly used in the art. Specifically, the photopolymerizable compound may include a semi-aromatic acrylate oligomer group consisting of urethane acrylate oligomer, epoxide acrylate oligomer, polyester acrylate, and polyether acrylate; And dipentaerythri nucleoacrylate, dipentaerythri pentaacrylate, pentaerythri tetraacrylate, pentaerythri triacrylate, trimethyl to propane triacrylate, glycerin propoxylate triacrylate, Trimethylpropane ethoxylate triacrylate, 1,6-nucleic acid diol. Diacrylate, tripropylene glycol One or more selected from the group of polyfunctional acrylate monomers consisting of diacrylate and ethylene glycol diacrylate can be used. The organic or inorganic fine particles may have a particle diameter of 1 to 10 mm 3.

The organic or inorganic fine particles are organic fine particles selected from the group consisting of acrylic resins, styrene resins, epoxy resins and nylon resins or inorganic particles selected from the group consisting of silicon oxide, titanium dioxide, indium oxide, tin oxide, zirconium oxide and zinc oxide. It may be particulate.

The hard coating layer may be formed from a coating composition comprising organic or inorganic fine particles, a photopolymerizable compound, a photoinitiator, and a high molecular weight (co) polymer. The anti-reflection film including such a hard coating layer is excellent in anti-glare effect.

Meanwhile, another example of the hard coating layer may include a binder resin including a photocurable resin; And an antistatic agent dispersed in the binder resin.

The photocurable resin included in the hard coating layer is a polymer of a photopolymerizable compound that may cause polymerization reaction when light such as ultraviolet rays is irradiated, and may be one commonly used in the art. Specifically, as the photopolymerizable compound, a polyfunctional (meth) acrylate-based monomer or oligomer may be used, wherein the number of (meth) acrylate-based functional groups is 2 to 10, 2 to 8 black is adjusted to 2 to 7 It is possible to secure the desired physical properties of the hard coating layer. More specifically, as the photopolymerizable compound, pentaerythri tri (meth) acrylate, pentaerythri tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythrocyte nucleus (Meth) acrylates, tripentaerythrates, hepta (meth) acrylates, toluene diisocyanates, xylene diisocyanates, nusamethylene diisocyanates, trimethylolpropane tri (meth) acrylates and trimethylolpropane polyhydroxy tri One or more selected from the group consisting of (meth) acrylates can be used. The antistatic agent may be a quaternary ammonium salt compound, a conductive polymer or a combination thereof. Here, the quaternary ammonium salt compound may be a compound having one or more quaternary ammonium salt groups in the molecule, it can be used without limitation low molecular type or polymer type. In addition, the conductive polymer is a low molecular type or a polymer type It can be used without limitation, and the kind thereof may be conventional in the art to which the present invention pertains, and is not particularly limited.

Binder resin of the photocurable resin; And the hard coating layer comprising an antistatic agent dispersed in the binder resin may further comprise at least one compound selected from the group consisting of alkoxy silane oligomer and metal alkoxide oligomer. The alkoxy silane compound may be conventional in the art, but preferably tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methacryloxypropyl It may be at least one compound selected from the group consisting of trimethoxysilane, glycidoxypropyl trimethoxysilane, and glycidoxypropyl trioxysilane.

In addition, the metal alkoxide-based oligomer may be prepared through the sol-gel reaction of the composition comprising a metal alkoxide-based compound and water. The sol-gel reaction can be carried out by a method similar to the method for producing an alkoxy silane oligomer described above. However, since the metal alkoxide compound may react rapidly with water, the sol-gel reaction may be performed by diluting the metal alkoxide compound in an organic solvent and slowly dropping water. At this time, in consideration of reaction efficiency, the molar ratio of the metal alkoxide compound to water (based on metal ions) is preferably adjusted within the range of 3 to 170.

Here, the metal alkoxide-based compound may be at least one compound selected from the group consisting of titanium tetra-isopropoxide, zirconium isopropoxide and aluminum isopropoxide.

On the other hand, the anti-reflection film may further include a substrate bonded to the other surface of the hard coating layer. The substrate may have a light transmittance of 90% or more and a haze of 1% or less. In addition, the material of the substrate may be triacetyl salose, cycloolefin polymer, polyacrylate, polycarbonate, polyethylene terephthalate and the like. In addition, the thickness of the base film may be 10 to 300 in consideration of productivity. However, the present invention is not limited thereto.

【Effects of the Invention】

Low refractive index layer according to an embodiment of the invention adversely affects the color of the polymer resin It can exhibit excellent optical properties such as low reflectance and high light transmittance and excellent mechanical properties such as high abrasion resistance and scratch resistance. In particular, the low refractive index layer may exhibit the above-described excellent physical properties even after alkali treatment, due to its excellent alkali resistance. Accordingly, when the low refractive index layer is introduced into the display device, it is expected that the manufacturing process can be simplified and the production speed and the yield will be significantly increased.

[Brief Description of Drawings]

1 is a graph showing reflectance according to the wavelength of the antireflection film prepared in Example 1. FIG.

2 is a graph showing reflectance according to the wavelength of the antireflection film prepared in Example 2. FIG.

3 is a graph showing reflectance according to the wavelength of the antireflection film prepared in Example 3. FIG.

4 is a graph showing reflectance according to the wavelength of the antireflection film prepared in Comparative Example 1. FIG.

5 is a graph showing reflectance according to the wavelength of the antireflection film prepared in Comparative Example 2. FIG.

6 is a graph showing reflectance according to the wavelength of the antireflective film prepared in Comparative Example 3. FIG.

7 is a graph showing reflectance according to the wavelength of the reflective film prepared in Comparative Example 4. FIG.

8 is a reflection prepared in Comparative Example 5

It is a graph which shows the reflectance according to the wavelength of a film.

[Specific contents to carry out invention]

Hereinafter, the operation and effects of the invention will be described in more detail with reference to specific embodiments of the invention. However, this is presented as an example of the invention, whereby the scope of the invention is not limited in any sense.

Preparation Example 1 Preparation of Hard Coating Film 1 (HD1) KYOEISHA salt type antistatic hard coating solution (50 wt% solids, product name: LJD-1000) was coated with triacetylcell film with # 10 mayer bar and dried at 90 ^° C for 1 minute, and then 150 mJ / cm ² UV light was irradiated to prepare a hard coat film (HD1) having a thickness of 5 / m. Preparation Example 2 Preparation of Hard Coating Film 2 (HD2)

30 g of pentaerythritriacrylate, 2.5 g of high molecular weight copolymers (BEAMSET 371, Arakawa, Epoxy Acrylate, molecular weight 40, 000), 20 g of methyl ethyl ketone and 0.5 g of leveling agent (Tego wet 270) After the addition, 2 g of an acrylic-styrene copolymer (volume average particle diameter: ΛΠ, manufactured by Seki sui Plast ic) as fine particles having a refractive index of 1.525 was added to prepare a hard coating composition. The hard coating composition thus obtained was coated on a triacetylcell film with # 10 mayer bar and dried at 90 ^° C. for 1 minute. 150 mJ / cm ² was irradiated to the dried material to prepare a hard coating film (HD2) having a thickness of 5 // m. Preparation Example 3 Preparation of Polysilsesquioxane 1

1L semi-unggi with nitrogen gas introduction tube, condenser and stirrer, i.ococtyl tr imethoxy si lane 36.57 g (0.156 mol), 3-methacryloxypropyl trimethoxysilane 23.34 g (0.094 mol) of (3-methacyloxypropyl tr imethoxysi lane) and 500 mL of methane were added thereto, followed by stirring at room temperature for 10 minutes. Thereafter, 280 g (0.77 mol, 25 wt% in methanol) of tetramethylammonium hydroxide was added thereto, and the reactor temperature was raised to 60 ^° C. under a nitrogen atmosphere, and reaction was performed for 8 hours. 15g of polyhedral oligomeric sesquioxane (P0SS) substituted with i-sooctyl group and methacryloxypropyl group were obtained by column chromatography and recrystallization. As a result of GP Chromatography, it was confirmed that the molar ratio (moles of methacryloxypropyl group / moles of i sooctyl group) of the methacryloxypropyl group to the i sooctyl group substituted in the silicon of polysilsesquioxane was about 0.6 to 1.67. Preparation Example 4 Preparation of Fluorine Compound 2

After thoroughly replacing a 2.0 L stainless steel autoclave with an electronic stirrer with nitrogen gas, 400 g of ethyl acetate, 53.2 g of perfluoro (propyl vinyl ether), 36.1 g of ethyl vinyl ether, 44.0 g of hydroxyethyl vinyl ether, 1.00 g of lauroyl peroxide, azo group-containing polydimethylsiloxane represented by the following formula (VPS1001 (trade name), ffako Pure Chemical Industries, Ltd. Geo 1) 6.0 g and a nonionic semi-ung emulsifier (NE-30 (trade name) ， 20.0 g of Asahi Toyo Kogyo Co., Ltd. was added, and after stirring down to -50 degrees C with dry ice methanol, the oxygen in the system was removed again with nitrogen gas.

Then 120.0 g of nucleus fluoropropylene were added and the win was started. When the temperature in the autoclave reached 60 ° C., the pressure was 5.3 × 10 ⁵ Pa. Then, the reaction was continued under stirring at 70 ° C. for 20 hours, and the reaction was stopped by subjecting the autoclave to the point where the pressure dropped to 1.7 × 10 ⁵ Pa. After reaching room temperature, the autoclave was opened after releasing unreacted monomer to obtain a polymer solution having a solid content of 26.4%. The obtained polymer solution was added to methanol to precipitate the polymer, and then washed with methanol and dried in vacuo at 50 ° C. to obtain 220 g of hydroxyl group-containing fluorine-containing polymer.

Into a 1-liter flask equipped with an electronic stirrer, glass shell and thermometer, 50.0 g of the hydroxyl group-containing fluorine polymer prepared previously, 0.01 g of 2,6-di-t-butylmethyl phenol and methyl iso as a polymerization inhibitor 370 g of butyl ketone (MIBK) were added and stirred at 20 ° C. until the hydroxyl group-containing fluorine polymer was dissolved in MIBK and the solution became clear.

Then 13.7 g of 2-acryloyloxyethyl isocyanate was added to the system, stirred until the solution became homogeneous, 0.1 g of dibutyltin dilaurate was added, and the temperature of the system was 55 5 ° C. By stirring for 5 hours, a MIBK solution of an ethylenically unsaturated group-containing fluorine-containing polymer (acrylic-modified fluorine-containing polymer) was obtained. 2 g of this solution was weighed and dropped into an aluminum dish, dried on a hot plate at 150 ^° C. for 5 minutes, and then reweighed to calculate the solid content. The solid content was 15.0 wt%.

(1) Preparation of photocurable coating composition for low refractive layer production

The components shown in Table 1 were mixed, and reacted with a solid content of 3% by weight in a solvent of MIBK methyl i sobutyl ketone).

Table 1

(Unit: g; Figures in parentheses vary between solids and content.)

1) Hollow silica dispersion: THRULYA 4320 (catalyzed product) in which hollow silica particles having a number average diameter of 50 nm were dispersed in MIBK at 20% by weight.

2) Polysilsesquioxane 1: Polysilsesquioxane 1 prepared according to Preparation Example 3 3) Polysilsesquioxane 2: T0AGOSEI CO. , Ltd. MAOSQ-F

4) Fluorine compound 1: A fluorine compound containing a photoreactive functional group, -0-CF ₂ CF ₂ -0-CF ₃ , -0- (CF ₂ ) ₃ -0- and -0-CF ₂ CF ₂ CF ₃ D907 RS907 dilutes 30% by weight in MIBK

5) Fluorine compound 2: Fluorine compound 2 prepared according to Preparation Example 4, and dispersed in MIBK at 15% by weight of solids (2) Preparation of low refractive layer and antireflection film (Examples 1 to 3 and Comparative Examples 1 to 5)

On the hard coat film described in Table 2 below, the photocurable coating composition obtained in Table 1 was coated with # 3 mayer bar and dried at 60 ^° C. for 1 minute. In addition, an antireflection film was prepared by irradiating 180 mJ / cm ² ultraviolet rays to the dried material under nitrogen purge to form a low refractive layer having a thickness of llOnm.

Experimental Example: Measurement of Physical Properties of Antireflection Film

The antireflection films obtained in the Examples and Comparative Examples were subjected to the experiments as follows.

1. Alkali pretreatment

Soak each of the antireflective films obtained in Examples 1 to 3 and Comparative Examples 1 to 5 for 2 minutes in an aqueous NaOH solution ^at 30 ^° C (diluted with 10 weight ¾> in distilled water), wash with running water, and wipe dry. gave. Subsequently, the anti-reflective film wiped with water was immersed in a 55 ^° C. aqueous NaOH solution (a solution of NaOH diluted in distilled water 10 times ¾) for 30 seconds, washed with running water, and then wiped dry. 2. Measurement of reflectance (Y) and color coordinate (b ^* )

Using the Sol idSpec 3700 (SHIMADZU) before and after the alkali pretreatment, the average reflectance and color coordinate values of the antireflective films prepared in Examples and Comparative Examples were measured.

Specifically, attaching a black tape to prevent light transmission on the surface where the hard coating layer of the base film is not formed, and immediately conditions at a sampling interval 1 nm, t ime constant 0.1 sec, sl it width 20 nm, medium scanning speed After fixing, the light of 380nm to 780nm wavelength region was irradiated to the low refractive layer of the antireflection film at room temperature.

When HD2 is used as the hard coat film, 100% T mode is applied, and when the hard coat film is ΗΕ ⁾ 1, the Measure mode is applied to 380ran to 780nm wavelength. The reflectance in the area was measured. Reflectance measurement results for the wavelength range of 380ran to 780nm of the antireflection films prepared in Examples and Comparative Examples are shown in FIGS. 1 to 8. The dotted lines in Figs. 1 to 8 are graphs showing the reflectance (y-axis) according to the wavelength (X axis) of the antireflection diameter before alkali treatment, and the solid line (——) is the wavelength of the antireflection film after alkali treatment. This graph shows the reflectance (y-axis) along the (x-axis).

In addition, the average reflectance and color coordinate values (b ^* ) in the wavelength range of 380iim to 780nm were derived from the reflectance through the UV-2401PC color analyzer program and are shown in Table 2.

3. Scratch resistance measurement

At the time before and after the pretreatment, the surface of the antireflection film obtained in Examples and Comparative Examples was rubbed with a steel wool of # 0000 grade and reciprocated 10 times at a speed of 24 rpm. The maximum load at which no scratches were observed visually under the LED 50W ceiling light was measured. The load is defined as the weight (g) per area (2 * 2 cm ² ) of 2 cm width and 2 cm length.

Table 2

/ S ₀ ] X 100

Referring to Table 2 and FIGS. 1 to 8, the antireflective films of Examples 1 and 2 exhibit significantly low reflectance and high scratch resistance in the visible light region (480 to 680 nm). It is confirmed that it is maintained at an excellent level. In contrast, the antireflective films of Comparative Examples 1 to 3 exhibit poor scratch resistance, and in particular, it is confirmed that scratch resistance remarkably decreases after alkali treatment.

On the other hand, the anti-reflection films of Examples 3 and 4 and 5 reduced the content of the vaporized silica contained in the low refractive index layer to achieve high scratch resistance, but similarly the anti-reflection films of Comparative Examples 4 and 5 after alkali treatment It is confirmed that scratch resistance is remarkably lowered.

Thereby, it is confirmed that the antireflection film can be provided that exhibits excellent alkali resistance only when the low refractive index layer that satisfies the specific conditions of the present invention is less than before and after alkali treatment. In particular, the low refractive index layer does not significantly decrease the optical properties such as reflectance or transmittance and the mechanical properties such as abrasion resistance or scratch resistance even when exposed to alkali depending on the manufacturing process of the polarizing plate. Application can be omitted, which simplifies the production process and reduces production costs. In addition, the low refractive layer is expected to contribute significantly to the production speed and productivity by maintaining excellent optical and mechanical properties even in the high temperature alkali treatment process.

Claims

[Claim]

[Claim 1]

Low refractive layer satisfying the following formula 1:

[Equation 1]

0.5> Ah ^* = \ b-b ^* ₀ l

In Equation 1,

b ' ₀ is the b ^* value of the color coordinate system set by the International Illumination Committee of the low refractive index layer,

I immersed the low refractive layer in a 10% by weight aqueous sodium hydroxide solution heated to 30 ^° C for 2 minutes, washed with water and wiped dry, and then 30 in a 10% by weight aqueous sodium hydroxide solution heated to 55 ^° C It is b ^* value of L ^* a ^* b ^* color coordinate system measured like the method of measuring b ^* ₀ with respect to the film prepared after immersing for a second and wash | cleaning with water, and wiped off water.

[Claim 2]

The low refractive index layer according to claim 1, wherein the b ^* ₀ value of Equation 1 is 1 to ᅳ 8. [Claim 3]

The low refractive index layer according to claim 1, wherein the value of Equation 1 is 1.5 to -8.5. [Claim 4]

The low refractive layer according to claim 1, which satisfies Equation 2:

[Equation 2]

30%> AS = [(So-Si) / S ₀ ] X 100

In Equation 2,

S ₀ is the maximum load that does not cause scratch when the steel wool of # 0000 grade is loaded and reciprocated 10 times at the speed of 24rpm and rubbed the surface of the low refractive layer.

¾ immersed the low refractive layer in a 10% by weight aqueous sodium hydroxide solution heated to 30 ^° C for 2 minutes, washed with water and wiped the water, and then 30 in a 10% by weight aqueous sodium hydroxide solution heated to 55 ^° C After immersion for a second, the scratches measured by the method of measuring So are not generated with respect to the film prepared by washing with water and wiping off the moisture. Maximum load.

[Claim 5]

The low refractive index layer according to claim 4, wherein the So value of the formula (2) is 250 to 800 g.

[Claim 6]

The low refractive index layer according to claim 4, wherein the value of Equation 2 is 200 to 800 g. [Claim 7]

The low refractive index layer according to claim 1, which exhibits a minimum reflectance in the wavelength region of 480 to 680 nm.

[Claim 8]

The low refractive index layer according to claim 1, wherein an average reflectance of light in a wavelength region of 380 to 780 nm is 0.9 to 2.5%.

[Claim 9]

The method of claim 1, wherein the photopolymerizable compound, a polysilsesquioxane substituted with at least one semi-aromatic functional group, a fluorine-based compound containing -0-CF ₂ CF ₂ -CF ₃ , inorganic particles and a photopolymerization initiator A low refractive index layer comprising a photocured product obtained by photocuring a photocurable coating composition.

[Claim 10]

The low refractive layer of claim 1; And a hard coating layer formed on one surface of the low refractive layer.