KR102384287B1 - Optical film, method for preparing optical film, and polarizer comprising the same - Google Patents

Abstract

The present invention is a light-transmitting substrate; and an anti-glare layer comprising a binder resin and two or more kinds of organic particulates dispersed in the binder resin, wherein one kind of organic particulates among the two or more kinds of organic particulates is an optical film, an optical film manufacturing method, and the same It relates to a polarizing plate including.

Description

Optical film, optical film manufacturing method, and a polarizing plate comprising the same

The present invention relates to an optical film, a method for manufacturing an optical film, and a polarizing plate comprising the same.

In an image display apparatus like an organic electroluminescent element (OLED) or a liquid crystal display element (LCD), it is calculated|required to prevent the fall of the contrast by reflection of external light or the reflection of an image, and the fall of visibility. For this purpose, an optical laminated film such as an antireflection film is formed on the surface of an image display device in order to reduce reflection or reflection of an image using light scattering or optical interference.

For example, in a liquid crystal display element etc., the optical laminated|multilayer film containing a glare-proof layer has been generally formed from before. The anti-glare layer mainly includes a binder and fine particles contained in the binder, and these fine particles are usually formed with irregularities so that a part protrudes from the surface of the binder. That is, since the anti-glare layer has a surface asperity due to the fine particles protruding from the surface of the binder, it is possible to control light scattering/light reflection and the like to suppress a decrease in visibility of the image display device.

However, in the case of the previously known optical film including an anti-glare layer, organic particles and inorganic nanoparticles were used together to form irregularities on the surface, but inorganic nanoparticles have low dispersibility in binders and solvents, so that inorganic nanoparticles There was a problem that aggregation occurred. In particular, the inorganic nanoparticles induce aggregation of organic particles while surrounding the surface of the organic particles. There is a problem in that a lot of irregularities are formed. In addition, due to such irregularities, the optical properties of the anti-glare layer are rather deteriorated, and the anti-glare properties that control light scattering/light reflection, etc., are not properly expressed. Do.

In addition, in the process of manufacturing an optical film including an anti-glare layer, aggregation occurs between inorganic nanoparticles and/or between organic particles surrounded by inorganic nanoparticles, which requires work such as filter replacement, thereby reducing productivity.

The present invention provides an anti-glare layer with improved dispersion stability of two or more organic particulates, and excellent optical properties such as low gloss, high contrast ratio, excellent image brightness and excellent anti-glare properties, including the same, and at the same time scratch resistance and stain resistance, etc. Its physical properties are also to provide an excellent optical film.

In addition, the present invention provides a method of manufacturing an optical film with improved productivity by preventing additional work due to particle agglomeration.

Another object of the present invention is to provide a polarizing plate including an optical film.

In the present specification, the light-transmitting substrate; and an anti-glare layer comprising a binder resin and two or more kinds of organic particulates dispersed in the binder resin, wherein one kind of organic particulates among the two or more kinds of organic particulates is cellulose particulates. An optical film may be provided.

In addition, in the present specification, on the light-transmitting substrate, cellulose fine particles; at least one organic fine particle different from the cellulose fine particle; and a reactive monomer or oligomer; and coating and curing the curable coating composition including the method may be provided.

Also, in the present specification, a polarizing plate including an optical film may be provided.

Hereinafter, an optical film, an optical film manufacturing method, and a polarizing plate including the same according to specific embodiments of the present invention will be described in more detail.

In this specification, the (meth)acrylate [(Meth)acrylate] is meant to include both acrylate and methacrylate.

In addition, the photocurable compound refers to a compound that causes a polymerization reaction when irradiated with light, for example, when irradiated with visible light or ultraviolet light.

In addition, unless it is specified that the steps constituting the manufacturing method described in this specification are sequential or sequential or there is another special order, one step and another step constituting one manufacturing method are in the order described in the specification. are not to be construed as limited. Accordingly, the order of the constituent steps of the manufacturing method may be changed within a range that can be easily understood by those skilled in the art, and in this case, changes apparent to those skilled in the art accompanying the same are included in the scope of the present invention.

According to one embodiment of the invention, a light-transmitting substrate; and an anti-glare layer comprising a binder resin and two or more kinds of organic particulates dispersed in the binder resin, wherein one kind of organic particulates among the two or more kinds of organic particulates is cellulose particulates. An optical film may be provided.

Accordingly, the present inventors have conducted research on an optical film, and an optical film comprising an anti-glare layer comprising two or more kinds of organic particulates, in particular, one kind of organic particulates among the two or more kinds of organic particulates is cellulose particulates, Through experiments, it was confirmed through experiments that it exhibits excellent optical properties such as low glossiness, high contrast ratio, excellent image clarity and excellent anti-glare properties, and at the same time physical properties such as scratch resistance and stain resistance, and completed the invention.

A fine concavo-convex shape may be formed on the surface of the anti-glare layer. Conventionally, organic particles and inorganic nanoparticles are used together in the anti-glare layer to form a concave-convex shape, so that the organic particles surrounded by the inorganic nanoparticles are excessively aggregated in a direction perpendicular to the surface of the anti-glare layer, or the dispersion stability of the inorganic nanoparticles is poor. Due to the low problem, excessive aggregation of the inorganic nanoparticles occurred, and the unevenness defect in which the unevenness was excessively large or formed on the surface of the anti-glare layer occurred. In addition, due to the unevenness, the optical properties are lowered, and the anti-glare properties for controlling light scattering/light reflection, etc., are not properly expressed, and the image is distorted at the site, resulting in deterioration of image clarity.

However, the anti-glare layer included in the optical film according to the embodiment does not use inorganic nanoparticles, and contains cellulose fine particles and other organic fine particles other than the cellulose fine particles (hereinafter referred to as “second organic fine particles”). By using only the two or more types of organic particulates, the dispersion stability of the organic particulates in the binder resin of the anti-glare layer is improved, thereby preventing the occurrence of problems such as irregularities in the related art.

In addition, when only the second organic fine particles other than the cellulose fine particles are used, the particles are evenly dispersed in the coating layer without aggregation between the particles, so that irregularities are not formed on the surface of the anti-glare layer, so that the anti-glare properties are not implemented.

On the other hand, since the cellulose fine particles have hydrophilicity due to the hydroxyl group on the surface, they may agglomerate or come into contact with the second organic fine particles due to strong attractive force. In addition, since the attractive force between the cellulose fine particles and the second organic fine particles is significantly greater than the attractive force between the second organic fine particles, aggregation between the cellulose fine particles and the second organic fine particles is likely to occur, but the aggregation between the second organic fine particles does not occur. It can be difficult.

Furthermore, since the cellulose fine particles are smaller in size (diameter of cross-section) than the second organic fine particles, when cellulose fine particles having different sizes and the second organic fine particles are aggregated to form irregularities, the second organic fine particles having a relatively large size Since the cellulose fine particles having a relatively small size are filled in the gaps formed by them, it is possible to prevent irregularities in which the irregularities are too large or too many are formed.

Therefore, when the cellulose fine particles are included in the anti-glare layer, it is possible to prevent unevenness defects and to form surface irregularities capable of improving the optical properties of the anti-glare layer. For this reason, the optical film exhibits excellent optical properties such as low gloss, high contrast ratio, excellent image sharpness and excellent anti-glare properties, and at the same time exhibits physical properties such as scratch resistance and stain resistance. there is.

In addition, on the surface of the anti-glare layer, since the second organic particulates aggregate in a direction parallel to the surface of the anti-glare layer to form irregularities, the irregularities include the entire second organic particulates or a part of the second organic particulates. It may be included, for example, 50% by volume or less of the second organic fine particles may be included.

The second organic fine particles are, for example, polystyrene, polymethyl methacrylate, polymethyl acrylate, polyacrylate, polyacrylate-co-styrene, polymethyl acrylate-co-styrene, polymethyl methacrylate -co-styrene, polycarbonate, polyvinyl chloride, polybutylene terephthalate, polyethylene terephthalate, polyamide, polyimide, polysulfone, polyphenylene oxide, polyacetal, epoxy resin, phenol resin, silicone resin, One selected from the group consisting of melamine resin, benzoguanine, polydivinylbenzene, polydivinylbenzene-co-styrene, polydivinylbenzene-co-acrylate, polydiallyl phthalate and triallyl isocyanurate polymer It may include the above polymer, but is not limited thereto.

The content of the cellulose fine particles relative to 100 parts by weight of the second organic fine particles may be 20 to 50 parts by weight, 25 to 45 parts by weight, or 30 to 40 parts by weight. When the content of the cellulose fine particles is less than 20 parts by weight relative to 100 parts by weight of the second organic fine particles, the two or more kinds of organic particles do not agglomerate, As a result, irregularities are not formed on the surface of the anti-glare layer. Anti-glare properties may be reduced, and when it exceeds 50 parts by weight, the aggregation of the two or more types of organic particles becomes excessive and the surface of the anti-glare layer becomes rough. image clarity, etc. Optical properties may be degraded.

The ratio of the cross-sectional diameter of the cellulose fine particles to the cross-sectional diameter of the second organic fine particles may be less than 1, 0.2 to 0.8, or 0.3 to 0.5. When the ratio of the cross-sectional diameter of the cellulose fine particles to the cross-sectional diameter of the second organic fine particles is 1 or more, the size of the aggregate of the cellulose fine particles and the second organic fine particles or the size of the aggregate of the cellulose fine particles and the cellulose fine particles increases, thereby causing irregularities As a result, the surface of the anti-glare layer may be rough, and optical properties such as image sharpness may be deteriorated.

On the other hand, the diameter of the cross section of the cellulose fine particles may be 0.2 to 10㎛, 0.3㎛ to 8㎛, or 0.4 to 5㎛, or 0.5 to 2㎛. If the diameter of the cellulose fine particles is less than 0.2㎛ The problem that the dispersibility of the particles is lowered and agglomeration of the cellulose fine particles occurs may occur, and if it exceeds 10 μm, As the particle agglomeration size increases, the surface becomes rough, which may cause a problem in that optical properties are deteriorated.

The diameters of the cellulose fine particles and the second organic fine particles can be measured, for example, by dynamic light scattering method, laser diffraction method, centrifugal sedimentation method, FFF (Field Flow Fractionation) method, pore electrical resistance method, etc. there is.

The two or more kinds of organic fine particles included in the anti-glare layer may be spherical, and in particular, the cellulose fine particles may be spherical. Due to the characteristic that the organic fine particles are spherical, unlike rod-shaped or amorphous, surface irregularities are formed evenly through agglomeration, so that excellent contrast ratio, image sharpness and anti-glare properties can be realized.

The binder resin in the anti-glare layer according to the embodiment is selected from the group consisting of a vinyl-based monomer, a vinyl-based oligomer, a (meth)acrylate-based monomer, a (meth)acrylate-based oligomer, and a (meth)acrylate-based polymer. one or more polymers or copolymers.

The vinyl-based monomer/oligomer or (meth)acrylate-based monomer/oligomer/polymer may include one or more, two or more, or three or more (meth)acrylate or vinyl groups.

Specific examples of the monomer or oligomer containing the (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) ) acrylate, tripentaerythritol hepta (meth) acrylate, torylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylic Late, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, butanediol dimethacrylate, hexaethyl methacrylate, butyl methacrylate, or a mixture of two or more thereof, or urethane-modified acrylate oligomer, epoxy side acrylate oligomers, ether acrylate oligomers, dendritic acrylate oligomers, or mixtures of two or more thereof. In this case, the weight average molecular weight of the oligomer may be 1,000 to 10,000.

Specific examples of the monomer or oligomer including the vinyl group include divinylbenzene, styrene, or paramethylstyrene.

In addition, the polymer or copolymer included in the binder resin may include a reactive acrylate oligomer group consisting of a urethane acrylate oligomer, an epoxy acrylate oligomer, a polyester acrylate, and a polyether acrylate; and dipentaerythritol hexaacrylate, dipentaerythritol hydroxy pentaacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, trimethylene propyl triacrylate, propoxylated glycerol triacrylate, trimethylpropane ethoxy tri At least one selected from the group consisting of polyfunctional acrylate monomers consisting of acrylate, 1,6-hexanediol diacrylate, propoxylated glycero triacrylate, tripropylene glycol diacrylate, and ethylene glycol diacrylate. It may further include a moiety derived from a monomer.

The (meth)acrylate-based polymer may be a polyfunctional (meth)acrylate-based polymer including two or more functional groups. The polyfunctional (meth)acrylate polymer has, for example, a weight average molecular weight of about 10,000 to about 800,000 g/mol, about 20,000 to about 700,000 g/mol, or about 30,000 to about 650,000 g/mol. can

The anti-glare layer may include 0.1 to 10 parts by weight, 0.2 to 9 parts by weight, or 0.3 to 8 parts by weight of the cellulose fine particles relative to 100 parts by weight of the binder resin. When the amount of the cellulose fine particles is less than 0.1 parts by weight relative to 100 parts by weight of the binder resin, the fine particles do not agglomerate and irregularities may not be formed on the surface of the anti-glare layer. If it is included in an amount exceeding 10 parts by weight, excessive aggregation of the fine particles may cause a problem in that the surface of the anti-glare layer is rough and optical properties such as image clarity are deteriorated.

The light-transmitting substrate included in the optical film according to the embodiment may use a plastic film having transparency. For example, it may be a cellulose ester-based substrate film, a polyester-based substrate film, a poly(meth)acrylate-based substrate film, a polycarbonate-based substrate film, a cycloolefin-based (COP) substrate film, or an acryl-based substrate film. However, the present invention is not limited thereto, and may be applied without any particular limitation to a substrate generally used for protecting the polarizer.

The optical film according to the exemplary embodiment may further include an adhesion promotion layer positioned between the light-transmitting substrate and the anti-glare layer, and formed in a form that erodes the light-transmitting substrate.

Due to the provision of the adhesion promoting layer, it has high hardness, high transparency, and high scratch resistance, and while thinning is possible, the adhesion between the adhesion promoting layer and the substrate may be excellent. Due to this, a stretched film with reduced adhesion due to polymer rearrangement in the stretching process, for example, a polyester film (PET), a cyclic olefin polymer film (COP), a polycarbonate film (PC), a polynorbornene-based film (PNB) ), and even when an acrylic film is used as a light-transmitting substrate, it can be applied without a separate primer treatment.

The adhesion promoting layer may include a cured resin of a photocurable monofunctional monomer having a reactive group capable of hydrogen bonding. The photocurable monofunctional monomer having a reactive group capable of hydrogen bonding is less evaporated than a solvent, and has good reactivity, so that it can be eroded on the light-transmitting substrate regardless of the characteristics of the light-transmitting substrate.

Due to such substrate erosion, chemical bonding between the light-transmitting substrate and the adhesion enhancing layer is possible after substrate erosion, so even if an additional adhesive or cross-linking agent is not included, excellent adhesion can be maintained regardless of the characteristics of the light-transmitting substrate. there is.

The adhesion promoting layer is preferably formed in a form in which about 20 to about 50% of the total thickness of the adhesion promoting layer including the light-transmitting substrate erosion portion erodes the substrate. When the erosion thickness of the light-transmitting substrate by the adhesion promoting layer is within the above range, the adhesion promoting layer can maintain excellent adhesion, and the optical film can maintain excellent mechanical properties such as high hardness and high transparency. .

The adhesion promoting layer has a reactive group capable of hydrogen bonding in the cured resin, and intermolecular hydrogen bonding is possible within the interface between the adhesion promoting layer and the light-transmitting substrate after curing, so that the adhesion with the substrate becomes more excellent. can

The reactive group capable of hydrogen bonding is not particularly limited as long as it is a reactive group or residue capable of hydrogen bonding, and for example, -OH group, -NH ₂ group, -NHR group, -COOH group, -CONH ₂ group, -NHOH Residues, such as a reactive group, such as a group, or -NHCO- bond, -NH- bond, -CONHCO- bond, -NH-NH- bond, in a molecule|numerator are mentioned. In addition, even the sites included on different resins are not particularly limited as hydrogen bonding sites as long as hydrogen bonding is possible with each other, for example, a reactive group or residue containing N or O -OH group or -NH ₂ If hydrogen bonding is possible with the group, it may be viewed as the hydrogen bonding site. In the above, R may be an aliphatic hydrocarbon, an aromatic hydrocarbon, and derivatives thereof, for example, an aliphatic hydrocarbon having 1 to 16 carbon atoms or 1 to 9 carbon atoms, an aromatic hydrocarbon having 5 to 30 carbon atoms or 5 to 16 carbon atoms, and their It may be a derivative.

The photocurable monofunctional monomer having such a reactive group capable of hydrogen bonding is not particularly limited, but for example, an amino group-containing monomer such as N-substituted (meth)acrylate or N,N-substituted (meth)acrylate, vinyl acetate or a hydroxyl group-containing monomer such as hydroxyalkyl (meth)acrylate, (meth)acrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propyl acid, 4-(meth) Carboxyl group-containing monomers such as acryloyloxy butyric acid, acrylic acid duplex, itaconic acid, maleic acid, or maleic anhydride, heterocyclic compounds such as vinyl pyrrolidone or acryloyl morpholine, 2-ureido-pyri It may be a midinone group-containing monomer or the like. Specifically, for example, tetrahydrofurfurylacrylate (THFA), tetrahydrofurfurylmethacrylate (THFMA), hydroxyethylacrylate (HEA), hydroxyethylmethacrylate (hydroxyethylmethacrylate HEMA) ), carboxyethylacrylate, carboxyethylmethacrylate, etc. may preferably be used, but is not limited thereto, and a photocurable monofunctional monomer having a reactive group capable of hydrogen bonding as described above. can be used without any special restrictions.

The photocurable monofunctional monomer may include a monofunctional monomer having a straight-chain structure or a branched-chain structure together with a monofunctional dilution monomer having a cyclic structure, and may be used alone or in combination of different types.

The adhesion promoting layer may include a cured resin of a photocurable monofunctional monomer and a polyfunctional acrylate-based monomer having a reactive group capable of hydrogen bonding. As described above, a polyfunctional acrylate-based monomer is polymerized with a photocurable monofunctional monomer having a reactive group capable of hydrogen bonding to form various types of bonds, and thus the adhesion promoting layer has better adhesion and scratch resistance. can have

The polyfunctional acrylate-based monomer is hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (tripropyleneglycoldiacrylate, TPGDA), ethylene glycol diacrylate (ethyleneglycoldiacrylate, EGDA), trimethylolpropane triacrylate ( trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxylated triacrylate (TMPEOTA), glycerol propoxylated triacrylate (GPTA), pentaerythritol tetraacrylate (PETA), And dipentaerythritol hexaacrylate (dipentaerythritol hexaacrylate, DPHA) may be mentioned, but is not limited thereto, and polyfunctional acrylate-based monomers commonly used in the field may be used without particular limitation.

When the cured resin is a cured resin of a photocurable monofunctional monomer and a polyfunctional acrylate-based monomer having a reactive group capable of hydrogen bonding, the total amount of the photocurable monofunctional monomer having a reactive group capable of hydrogen bonding is about 100 parts by weight. The polyfunctional acrylate-based monomer may be cured in an amount of about 10 to about 150 parts by weight. When the cured resin is cured within the above range, the optical film may have sufficient flexibility and adhesion without deterioration of physical and optical properties.

The optical film may further include a hard coating layer between the adhesion promoting layer and the anti-glare layer. The hard coating layer is for increasing the hardness of the optical film, and if it is a hard coating layer generally used in the art, it may be used without any particular limitation.

The higher the haze value of the optical film according to the embodiment, the greater the degree of diffusion of external light and the excellent anti-glare effect. may appear. In contrast, the optical film of the embodiment may control the haze to 50% or less, 45% or less, 40% or less, or 35% or less, thereby improving the anti-glare effect, and preventing the contrast ratio from lowering.

According to another embodiment of the invention, on the light-transmitting substrate, cellulose fine particles; at least one organic fine particle different from the cellulose fine particle; and reactive monomers or oligomers; and coating and curing the curable coating composition comprising a.

The light-transmitting substrate is the same as described above for the optical film.

Conventionally, a coating composition was prepared including organic fine particles and inorganic nanoparticles, but due to inorganic nanoparticles having low dispersibility in binders and solvents, aggregation of inorganic nanoparticles occurred, and additional work such as filter replacement was required to reduce productivity. There was a problem.

However, in the curable coating composition of the other embodiment, the dispersion stability of the organic fine particles in the composition is improved by using only two or more kinds of organic fine particles including cellulose fine particles and second organic fine particles without using inorganic nanoparticles. This eliminates the need for additional work, improving productivity. In addition, as described above, the optical film including the anti-glare layer prepared from such a curable coating composition exhibits excellent optical properties such as low gloss, high contrast ratio, excellent image brightness and excellent anti-glare properties, and at the same time scratch resistance and resistance Physical properties such as contamination may be indicated.

On the other hand, the type of the second organic fine particles, the content of the cellulose fine particles relative to 100 parts by weight of the second organic fine particles, the diameter/density ratio of the cellulose fine particles to the second organic fine particles, the diameter/shape of the cellulose fine particles, etc. is the same as described above for the optical film.

The curable coating composition comprises a reactive monomer, a reactive oligomer or It may contain a reactive polymer.

The curable coating composition may be photocurable or thermosetting, and may have both photocurable and thermosetting properties. When the curable coating composition is photocurable, the curable coating composition may further include a photoinitiator, and the curable coating composition may further include a thermosetting agent or a curing catalyst.

said reactive monomer, reactive oligomer or The reactive polymer may be, for example, a vinyl-based monomer or oligomer or a (meth)acrylate-based monomer, oligomer or polymer, and a vinyl-based monomer/oligomer or (meth)acrylate-based step/oligomer/polymer is optical As described above in the film.

Meanwhile, the photoinitiator is, for example, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1-[4-( 2-Hydroxyethoxy)phenyl]-2-methyl-1-propanone, methylbenzoylformate, α,α-dimethoxy-α-phenylacetophenone, 2-benzoyl-2-(dimethylamino)-1- [4-(4-morpholinyl)phenyl]-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone di Phenyl(2,4,6-trimethylbenzoyl)-phosphine oxide or bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide may be exemplified, but the present invention is not limited thereto. In addition, products currently on the market include Irgacure 184, Irgacure 500, Irgacure 651, Irgacure 369, Irgacure 907, Darocur 1173, Darocur MBF, Irgacure 819, Darocur TPO, Irgacure 907, Esacure KIP 100F, and the like. These photoinitiators may be used alone or in mixture of two or more different types.

The curable coating composition may include an organic solvent, and the organic solvent includes an alcohol-based solvent such as methanol, ethanol, isopropyl alcohol, butanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy- Alkoxy alcohol solvents such as 2-propanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, and cyclohexanone, propylene glycol monopropyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether , Ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethyl glycol monoethyl ether, diethyl glycol monopropyl ether, diethyl glycol monobutyl ether, diethylene glycol-2-ethylhexyl ether An ether-based solvent such as benzene, toluene, or an aromatic solvent such as xylene may be used alone or in combination.

The method of applying the curable coating composition is not particularly limited as long as it can be used in the technical field to which the present technology belongs, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, micro gravure A coating method, a comma coating method, a slot die coating method, or a lip coating method may be used.

In the case of forming the anti-glare layer by irradiating the curable coating composition with ultraviolet rays, the irradiation amount of ultraviolet rays may be, for example, about 20 to about 600 mJ/cm ² . The light source of the ultraviolet irradiation is not particularly limited as long as it can be used in the technical field to which the present technology belongs, and for example, a high-pressure mercury lamp, a metal halide lamp, a black light fluorescent lamp, etc. may be used.

In the optical film manufacturing method according to another embodiment, before the step of coating and curing the curable coating composition, the composition for forming an adhesion promoting layer is applied on a light-transmitting substrate and irradiated with ultraviolet rays to form an adhesion promoting layer It may include further steps.

Thereafter, after the curable coating composition is applied on the adhesion promoting layer, an anti-glare layer may be formed. That is, since the adhesion promoting layer is formed in the form of erosion on the light-transmitting substrate, it may be formed before forming the anti-glare layer.

The composition for forming the adhesion promoting layer may include a photocurable monofunctional monomer having a reactive group capable of hydrogen bonding, and the photocurable monofunctional monomer having a reactive group capable of hydrogen bonding is as described above for the optical film.

In addition, the composition for forming the adhesion promoting layer may include a photopolymerization initiator and an organic solvent, which may use the photopolymerization initiator and the organic solvent included in the anti-glare base film.

The composition for forming the adhesion promoting layer is applied to a light-transmitting substrate and then photocured to form an adhesion promoting layer, wherein the photocuring is a photocurable monofunctional monomer and/or the polyfunctional acrylate having a reactive group capable of hydrogen bonding. This may be carried out until some of the monomers are cross-linked. Partially crosslinked means that the photocurable monofunctional monomer having a reactive group capable of hydrogen bonding and the polyfunctional acrylate-based monomer are partially crosslinked less than 100% when 100% is fully crosslinked. . For example, when about 30 to about 60 mol%, or about 40 to about 50 mol% of the functional groups included in the photocurable monofunctional monomer and the polyfunctional acrylate-based monomer having a reactive group capable of hydrogen bonding are crosslinked can be done up to After photo-curing in which only a portion is cross-linked, adhesion to the photo-curing substrate can be more sufficiently secured through application of the composition for forming an anti-glare layer and photo-curing process, and curling or curing shrinkage that may occur during the photo-curing process is prevented can do.

According to another embodiment of the present invention, there is provided a polarizing plate including the above-described optical film.

The optical film may act as, for example, a polarizer protective film to exhibit the excellent properties described above. Accordingly, it is possible to provide a polarizing plate including a polarizer and an optical film provided on at least one surface of the polarizer to act as a polarizer protective film.

The polarizer exhibits a characteristic of extracting only light vibrating in one direction from incident light while vibrating in several directions. These properties can be achieved by stretching polyvinyl alcohol (PVA), which has absorbed iodine, with strong tension. For example, more specifically, a step of swelling the PVA film by immersing it in an aqueous solution to swell, dyeing the swollen PVA film with a dichroic material that imparts polarization, stretching the dyed PVA film ) to form a polarizer through a stretching step of arranging the dichroic dye material side by side in the stretching direction, and a complementary color step of correcting the color of the PVA film that has undergone the stretching step.

The optical film may be attached to both surfaces of the polarizer, or may include a general-purpose protective film that is attached to only one surface of the polarizer and is typically used for protecting the polarizer, such as TAC, on the other surface.

The flat plate may be used as an upper polarizing plate of a liquid crystal display device, and due to the excellent optical properties of the optical film, it is possible to prevent a decrease in contrast or a decrease in visibility due to reflection of external light or reflection of an image in the liquid crystal display device. .

According to the present invention, the dispersion stability of two or more kinds of organic fine particles contained in the anti-glare layer is improved, and excellent optical properties such as low gloss, high contrast ratio, excellent image brightness and excellent anti-glare properties are exhibited, and at the same time scratch resistance and resistance to scratches An optical film excellent in physical properties such as staining properties and a polarizing plate including the same may be provided. In addition, the present invention may provide a method for manufacturing an optical film with improved productivity by preventing additional operations due to particle agglomeration.

The invention is described in more detail in the following examples. However, the following examples only illustrate the present invention, and the content of the present invention is not limited by the following examples.

< production example : anti-glare layer Preparation of Forming Composition>

(One) production example One

100 parts by weight of pentaerythritol triacrylate, 6.2 parts by weight of Irgacure 184 as a photopolymerization initiator based on 100 parts by weight of the pentaerythritol triacrylate, 100 parts by weight of ethyl alcohol as an organic solvent, polymethylmethacrylate-co-styrene fine particles ( A composition for forming an anti-glare layer was prepared by mixing 4.0 parts by weight of spherical PMMA/PS fine particles, refractive index (n)=1.555, diameter: 2.0 μm), and 1.5 parts by weight of cellulose fine particles (spherical shape, diameter of cross-section: 1 μm).

(2) Preparation Example 2

100 parts by weight of pentaerythritol triacrylate, 6.2 parts by weight of Irgacure 184 as a photopolymerization initiator based on 100 parts by weight of the pentaerythritol triacrylate, 50 parts by weight of ethyl alcohol as an organic solvent, 50 parts by weight of 2-butyl alcohol, polymethyl meta An anti-glare layer by mixing 2.8 parts by weight of acrylate-co-styrene fine particles (spherical PMMA/PS fine particles, refractive index (n) = 1.555, diameter: 2.0 μm) and 1.1 parts by weight of cellulose fine particles (spherical shape, diameter of cross section: 1 μm) A composition for forming was prepared.

(3) Preparation 3

100 parts by weight of trimethylol propyl triacrylate, 6.2 parts by weight of Irgacure 184 as a photopolymerization initiator based on 100 parts by weight of trimethylol propyl triacrylate, 50 parts by weight of ethyl alcohol as an organic solvent, 50 parts by weight of 2-butyl alcohol, polymethyl meta An anti-glare layer by mixing 4.7 parts by weight of acrylate-co-styrene fine particles (spherical PMMA/PS fine particles, refractive index (n) = 1.555, diameter: 3.5 μm) and 1.0 parts by weight of cellulose fine particles (spherical shape, diameter of cross section: 2 μm) A composition for forming was prepared.

(4) comparison Preparation Example 1

A composition for forming an anti-glare layer was prepared in the same manner as in Preparation Example 1, except that the cellulose fine particles were not used.

(5) comparison Preparation Example 2

A composition for forming an anti-glare layer was prepared in the same manner as in Preparation Example 1, except that the polymethyl methacrylate-co-styrene fine particles were not used, and 4.0 parts by weight of the cellulose fine particles were used.

(6) comparison Preparation 3

Instead of 2.8 parts by weight of the polymethyl methacrylate-co-styrene fine particles and 1.1 parts by weight of the cellulose fine particles, 4.0 parts by weight of the polymethyl methacrylate-co-styrene fine particles and 0.8 parts by weight of silica nanoparticles (30% solids in isopropyl alcohol) A composition for forming an anti-glare layer was prepared in the same manner as in Preparation Example 2, except that part was used.

(7) comparison Preparation 4

2.8 parts by weight of the polymethyl methacrylate-co-styrene fine particles and 1.1 parts by weight of cellulose fine particles instead of 4.0 parts by weight of cellulose fine particles and 0.8 parts by weight of silica nanoparticles (30% solids in isopropyl alcohol) except that 0.8 parts by weight was used, A composition for forming an anti-glare layer was prepared in the same manner as in Preparation Example 2.

(8) comparison Production Example 5

A composition for forming an anti-glare layer was prepared in the same manner as in Preparation Example 2, except that 0.8 parts by weight of silica nanoparticles (30% solids in isopropyl alcohol) were further used.

< Example and comparative example : Manufacture of optical film>

As shown in Table 1 below, on a triacetyl cellulose (TAC) base film having a thickness of 60 μm, the compositions prepared in Preparation Examples 1 to 3 and Comparative Preparation Examples 1 to 5, respectively, were coated with a bar coating method as an anti-glare layer After drying, it was applied so that the thickness was 4~5um. Thereafter, after drying at 90° C. for 2 minutes, ultraviolet rays of 200 mJ/cm ² were irradiated with a mercury lamp to prepare an anti-glare layer.

< Experimental example : Optical Film Evaluation>

The prepared optical film was measured according to the following method, and the results are shown in Table 1 below.

One. haze Measure

A specimen of 4 cm × 4 cm was prepared from the optical film obtained in each of the Examples and Comparative Examples and measured three times with a haze meter (HM-150, light source A, Murakami Corporation) to calculate the average value, which was calculated as the total haze value . Haze was measured according to JIS K 7136 standard.

2. anti-glare evaluation

When the optical film obtained in each of Examples and Comparative Examples was illuminated under a fluorescent lamp, the anti-glare effect of the lamp was visually confirmed, and the evaluation criteria are as follows.

Good: Lamp has anti-glare effect

Bad: The lamp image is clearly formed

3. Gloss measurement

For the optical films obtained in each of Examples and Comparative Examples, glossiness was measured at a light incident angle of 60° using a photometer (Gloss Meter, BYK).

4. Evaluation of surface irregularities

On the surface of the 30 cm × 30 cm area of the optical film obtained in each of the Examples and Comparative Examples, the number of irregularities protruding non-uniformly convexly was counted to evaluate the properties of the irregularities formed on the surface of the optical film. Specifically, the evaluation results of 5 inspectors skilled in the visual evaluation of irregularities were averaged, and the evaluation criteria are as follows. On the other hand, in Table 1 below, when unevenness is not generated on the surface, it is indicated by '-'.

Good: less than 10

Bad: 10 or more

5. Pencil hardness

The optical film obtained in each of Examples and Comparative Examples was reciprocated 5 times with a load of 500 g according to the measurement standard JIS K5400 using a pencil hardness measuring instrument, and then pencil hardness without scratches was confirmed.

6. scratch resistance

For the optical film obtained in each of the Examples and Comparative Examples, a 500 g load was applied to Steel wool #0000 and rubbed 10 times by reciprocating, and then visually averaged to see if scratches occurred, and the evaluation criteria are as follows.

Good: no scratches

Bad: Scratches

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 composition Preparation Example 1 Preparation Example 2 Preparation 3 Comparative Preparation Example 1 Comparative Preparation Example 2 Comparative Preparation Example 3 Comparative Preparation Example 4 Comparative Preparation Example 5 haze 4.2 3.2 21.0 3.8 2.7 3.5 2.8 5.3 anti-glare Good Good Good error error Good error Good Glossiness (60°) 82 85 52 89 90 85 90 75 Concave-convex characteristics Good Good Good - - error - error pencil hardness 3H 3H 3H 3H 3H 3H 3H 3H scratch resistance Good Good Good Good Good Good Good Good

According to Table 1, it was confirmed that the optical films of Examples 1 to 3 were excellent in anti-glare properties and unevenness properties, compared to the optical films of Comparative Examples 1 to 5.

On the other hand, since the anti-glare layer of Comparative Example 1 includes only the second organic particles, it was confirmed that agglomeration was not made with only the second organic particles, so that irregularities were not formed on the surface, and the anti-glare layer of Comparative Example 2 contained only cellulose particles, , it was confirmed that sufficient agglomeration was not made so that irregularities could be formed on the surface. In addition, since the anti-glare layer of Comparative Example 3 includes the second organic fine particles and inorganic nanoparticles, it was confirmed that the particles were excessively agglomerated in the thickness direction of the anti-glare layer to have poor concavo-convex properties, and the anti-glare layer of Comparative Example 4 was It was confirmed that since only cellulose fine particles and inorganic nanoparticles were included, sufficient agglomeration to form irregularities on the surface was not achieved. In addition, since the anti-glare layer of Comparative Example 5 additionally contains inorganic fine particles, it was confirmed that the particles were excessively agglomerated in the thickness direction of the anti-glare layer, resulting in poor concavo-convex characteristics.

Claims (14)

light transmissive substrate; and an anti-glare layer comprising a binder resin and two or more different types of organic particles dispersed in the binder resin;
One type of organic fine particles among the two or more different types of organic fine particles is cellulose fine particles, an optical film.
According to claim 1,
The anti-glare layer is polystyrene, polymethyl methacrylate, polymethyl acrylate, polyacrylate, polyacrylate-co-styrene, polymethyl acrylate-co-styrene, polymethyl methacrylate-co-styrene, polycarbonate , polyvinyl chloride, polybutylene terephthalate, polyethylene terephthalate, polyamide, polyimide, polysulfone, polyphenylene oxide, polyacetal, epoxy resin, phenol resin, silicone resin, melamine resin, benzoguamine, A second containing at least one polymer selected from the group consisting of polydivinylbenzene, polydivinylbenzene-co-styrene, polydivinylbenzene-co-acrylate, polydiallyl phthalate and triallyl isocyanurate polymer containing organic particulates,
The second organic fine particles are included in the two or more different types of organic fine particles, an optical film.

3. The method of claim 2,
The content of the cellulose fine particles relative to 100 parts by weight of the second organic fine particles is 20 to 50 parts by weight, the optical film.
3. The method of claim 2,
The ratio of the cross-sectional diameter of the cellulose fine particles to the cross-sectional diameter of the second organic fine particles is less than 1, the optical film.
5. The method of claim 4,
The ratio of the cross-sectional diameter of the cellulose fine particles to the cross-sectional diameter of the second organic fine particles is 0.2 to 0.8, the optical film.
According to claim 1,
The diameter of the cross section of the cellulose fine particles is 0.2 to 10㎛, the optical film.
According to claim 1,
The at least two different types of organic fine particles are spherical, optical film.
According to claim 1,
The light-transmitting substrate is a cellulose ester-based substrate film, a polyester-based substrate film, a poly(meth)acrylate-based substrate film, a polycarbonate-based substrate film, a cycloolefin-based (COP) substrate film, or an acrylic (Acryl)-based substrate film. , optical film.
According to claim 1,
The binder resin is one or more polymers or copolymers selected from the group consisting of a vinyl-based monomer, a vinyl-based oligomer, a (meth)acrylate-based monomer, a (meth)acrylate-based oligomer, and a (meth)acrylate-based polymer. comprising, an optical film.
According to claim 1,
Positioned between the light-transmitting substrate and the anti-glare layer, the optical film further comprising an adhesion promoting layer formed in the form of eroding the light-transmitting substrate.
A polarizing plate comprising the optical film of claim 1.
on the light-transmitting substrate,
cellulose microparticles; at least one organic fine particle different from the cellulose fine particle; And reactive monomers, reactive oligomers or reactive polymers; and coating and curing the curable coating composition comprising the, the method of claim 1 .
13. The method of claim 12,
Before the step of coating and curing the curable coating composition,
Forming an adhesion promoting layer by applying a composition for forming an adhesion promoting layer on a light-transmitting substrate and irradiating ultraviolet rays to form an adhesion promoting layer; further comprising, an optical film manufacturing method.
14. The method of claim 13,
The composition for forming the adhesion promoting layer comprises a photocurable monofunctional monomer having a reactive group capable of hydrogen bonding and a photopolymerization initiator, an optical film manufacturing method.