WO2018110950A1

WO2018110950A1 - Optical film and image display device comprising same

Info

Publication number: WO2018110950A1
Application number: PCT/KR2017/014573
Authority: WO
Inventors: 서정현; 장영래; 박진영; 이한나
Original assignee: 주식회사 엘지화학
Priority date: 2016-12-12
Filing date: 2017-12-12
Publication date: 2018-06-21
Also published as: CN110050206A; CN110050206B; CN110050206B9

Abstract

The present invention relates to an optical film comprising a light transmissive base film, such as a polyester base film, and an anti-glare layer. The present invention relates to an optical film and an image display device comprising same, the optical film enabling effective inhibition of interference pattern occurrences from a base film, showing excellent anti-glare properties, and having excellent scratch resistance, adhesiveness between the base film and an anti-glare layer and the like.

Description

[Name of invention]

Optical film and image display device including the same

Technical Field

Cross Citation with Related Application (s)

This application is filed with Korean Patent Application No. 10-2016-December 12, 2016.

0168858 and Korean Patent Application No. 10-2017-December 11, 2017

Claiming the benefit of priority based on 0169719, all contents disclosed in the literature of the relevant Korean patent applications are incorporated as part of this specification.

The present invention relates to an optical film including a transparent base film and an antiglare layer, such as a polyester-based base film, can effectively suppress the occurrence of interference fringes derived from the base film, it is possible to implement excellent anti-glare characteristics, The present invention relates to an optical film excellent in scratch resistance, adhesion between the base film and the antiglare layer, and an image display device including the same.

[Background]

In an image display device such as an organic electroluminescent element (OELD) or a liquid crystal display element (LCD), it is required to prevent a decrease in contrast and a decrease in visibility due to reflection or reflection of external light. To this end, in order to reduce image reflection and reflection by using light scattering or optical interference, an optical laminated film such as an antireflection film is formed on the surface of the image display device.

For example, in a liquid crystal display element etc., the optical red film containing an anti-glare layer has been generally formed before. The anti-glare layer mainly includes a binder and fine particles contained in the binder, and these fine particles are usually formed so that a part of the anti-glare surface protrudes from the binder surface. That is, the anti-glare layer can suppress the visibility deterioration of the image display device by controlling the light scattering / light reflection, etc. of the fine particles protruding on the binder surface.

However, in the case of the previously known antiglare layer and the optical film, the glossiness of the surface is often high, and in many cases, reflection of external light is still difficult to be suppressed, which is sufficient to reduce the contrast drop of the image display device. Could not be suppressed. Moreover, in the previous anti-glare layer and the optical film, as the crosslinking density of the binder was not sufficient, the scratch resistance of the surface was also insufficient in many cases.

On the other hand, optical films known from the prior art generally have a form in which an antiglare layer is formed on a transparent substrate film, and as such a transparent substrate film, a cellulose ester-based film represented by triacetyl cellulose (TAC) This is the most widely used. Such a cellulose ester-based film has advantages such as excellent transparency and optical isotropy, almost no retardation in the plane, so that no interference fringes are generated, and there is little adverse effect on the display quality of the display device. However, as the Austrian selreul ester film is not only a ^{cost-disadvantage,} material, there is a drawback with high moisture permeability poor water resistance. Due to this high moisture permeability / poor water resistance, a considerable amount of moisture permeation can occur continuously during use, causing the phenomenon of lifting, which can cause light leakage.

Due to the shortcomings of such cellulose ester-based films, in recent years, attempts have been made to replace polyester-based films such as polyethylene terephthalate-based films as base films of the polarizer protective optical films. Such a polyester-based film is inexpensive, has excellent water resistance, hardly causes light leakage, and has excellent mechanical properties.

However, such a polyester-based film includes an aromatic ring having a high refractive index in the structure, and has a disadvantage in that it exhibits anisotropy due to the difference in elongation of MD / TD in the film forming process. As a result, when the polyester-based film is applied as the base film of the optical film, interference fringes are generated due to the transmission / reflection of light, which causes a problem that the visibility of the display device is lowered.

In addition, the anti-glare layer formed on the light-transmissive base film usually includes a (meth) acrylate-based binder, and when the polyester-based film is applied as the base film of the optical film, such a base film and the anti-glare layer The adhesiveness between them was also not enough.

[Detailed Description of the Invention]

[Technical problem]

Accordingly, the present invention is an optical film including a light-transmissive base film and an anti-glare layer, which can effectively suppress the occurrence of interference fringes derived from the base film, can realize excellent anti-glare properties, scratch resistance, the base film And an optical film having excellent adhesion between the antiglare layers.

This invention also provides the image display apparatus containing the said optical film.

[Technical solution]

The present invention is a polyester base film; And

An antiglare layer comprising a binder containing a (meth) acrylate-based crosslinked polymer, a micron scale organic fine particle dispersed on the binder, and a nano (nm) scale inorganic fine particle dispersed on the binder. And, wherein the (meth) acrylate-based crosslinked polymer is 100 parts by weight of the binder _. On the basis of 0 to 20 parts by weight of a monofunctional (meth) acrylate-based compound and a crosslinked polymer of a trifunctional or higher polyfunctional (meth) acrylate-based compound,

The absolute value of the refractive index difference of the said organic fine particle and a binder is less than 0.15, The absolute value of the refractive index difference of the said inorganic fine particle and a binder is less than 0.15,

An optical film having a 20 ^° glossiness of 50% to 70% and a 60 ^° glossiness of 75% to 90% of the surface of the antiglare layer is provided.

In addition, the present invention is a light-transmitting base film; And

A antiglare layer formed on the base film, the antiglare layer comprising a binder comprising a (meth) acrylate-based crosslinked polymer, and one or more fine particles having a sub-micron (suborn) scale dispersed on the binder,

The (meth) acrylate-based crosslinked polymer is a binder of the antiglare layer It is a crosslinked polymer of 0-20 weight part of monofunctional (meth) acrylate type compound with a trifunctional or more than trifunctional polyfunctional (meth) acrylate type compound based on 100 weight part,

The absolute value of the difference in refractive index between the fine particles and the binder of the antiglare layer is less than 0.15,

The polyfunctional (meth) acrylate-based compound is a polyurethane-based polymer having a (meth) acrylate-based compound having a 3-6 functional monomolecular form and / or a (meth) acrylate-based functional group having 10 or more functional groups, poly (meth) Provided are an optical film comprising an acrylic polymer or a polyester polymer.

This invention also provides the image display apparatus containing the said optical film. Hereinafter, an optical film and an image display device including the same according to a specific embodiment of the present invention will be described.

As used herein, micron (/) scale refers to having a particle size or particle size of less than 1 mm, ie, less than 1000 mm 3, and referred to as nano (nm) scale ^. Refers to a particle size or particle size of less than 1 μη \, ie, less than 1000 nm, and refers to a sub- / zm scale, referred to as a micron scale or nanoscale particle size or particle size. .

In addition, the photopolymerizable compound is collectively referred to as a compound that causes crosslinking, curing or polymerization reaction when light is irradiated, for example, visible light or ultraviolet light.

In addition, (meth) acryl [(meth) acryl] is meant to include both acryl and methacryl.

Also, a (co) polymer is meant to include both co-pdymers and homo-polymers.

Also, silica hollow particles are silica particles derived from a silicon compound or an organosilicon compound. It means a particle in the form of empty space on the surface and / or inside of the particle. According to one embodiment of the invention, the polyester-based substrate film; And

An antiglare layer comprising a binder containing a (meth) acrylate-based crosslinked polymer, micron (/) scale organic fine particles dispersed on the binder, and nano (nm) scale inorganic fine particles dispersed on the binder; To include, the (meth) acrylate-based crosslinked polymer, based on 100 parts by weight of the binder, 0 to 20 parts by weight of a monofunctional (meth) acrylate-based compound, and a trifunctional or higher polyfunctional (meth) acrylate-based Crosslinked polymer of the compound,

The absolute value of the refractive index difference of the organic fine particles and the binder is less than 0.15, The absolute value of the refractive index difference of the inorganic fine particles and the binder is less than 0.15,

According to the inventors and the results of continuous experiments, the anti-glare layer (meth) acrylate type ^; Together with the binder, one or more fine particles, for example, organic and inorganic fine particles having a particle size of a predetermined scale are included, respectively, while the difference between the refractive index of the binder and the refractive index of each fine particle is less than 0.15, for example, 0. It has been confirmed that the antiglare characteristics of the antiglare and the optical film can be improved by controlling the amount to 0.12, black from 0.01 to 0.12, and black from 0.02 to 0.12.

This is presumed to be because the gloss H of the surface of the antiglare layer can be reduced as a result of controlling the difference in refractive index between each fine particle and the binder in the above-described range, and as a result, reflection of external light can be effectively controlled. In addition, it has been confirmed that generation of interference fringes derived from a light-transmitting base film such as the polyester base film can also be effectively suppressed by such refractive index control / gloss reduction.

_. In addition, the optical film of the embodiment is a (meth) acrylate-based In forming the binder, based on 100 parts by weight of the total binder, 0 to 20 parts by weight of the monofunctional (meth) acrylate-based compound, trifunctional or higher polyfunctional (meth) acrylate-based compound, more specifically, 3 to A binder is formed as a crosslinked (co) polymer of a 6-functional monomolecular (meth) acrylate compound and a compound (polymer) having 10 or more functional (meth) acrylate-based functional groups. As such, crosslinking a reduced content of a monofunctional (meth) acrylate-based compound with a relatively large amount of a trifunctional or higher polyfunctional (meth) acrylate-based compound, in particular a multifunctional compound comprising a compound of 10 or more functionalities ( By using the co-polymerized binder, it was confirmed that the adhesion between the substrate and the antiglare layer of the optical film can be improved and the scratch resistance of the optical film can be improved. This is presumably because the crosslinking density, hardness, etc. of a binder become higher by use of the above-mentioned binder. Furthermore, it has been confirmed that the use of such a specific binder can further reduce the glossiness of the surface of the antiglare layer, and as a result, it is possible to more effectively control the reflection of external light and the like. Therefore, generation | occurrence | production of the interference fringe derived from the light transmissive base film like the said polyester base film can also be suppressed further.

Accordingly, the optical film of the above-described embodiment can exhibit excellent scratch resistance while improving visibility and the like of the image display element. Hereinafter, the optical film of one embodiment will be described in detail for each element.

The optical film of the embodiment includes a light-transmitting base film exhibiting at least light transmittance to visible light, and representatively includes a polyester-based base film. In this polyester-based ^material, the film can be applied to both a film comprising any of a polyester resin known to be applicable to the substrate film of the optical film from the previous without limitation.

However, in consideration of the excellent mechanical properties, water resistance and the like of the base film, the polyester base film is 30 to 200 ^ ηι, or 40 to 150 A polyethylene terephthalate (PET) based material film has a thickness adequate to the ^"search.

In addition, the optical film of one embodiment includes an antiglare layer formed on the base film. As described above, by controlling the composition of the binder included in the antiglare, the refractive index, and the difference between the refractive index and the binder refractive index of the fine particles included therein, the anti-glare and scratch resistance of the anti-glare layer and the optical film is excellent Can be expressed, and interference fringes derived from the base film can be reduced.

In this anti-glare layer, the binder is 0 to 20 parts by weight, or 0 to 18 parts by weight, or 3 to 17 parts by weight of the monofunctional (meth) acrylate-based compound and the remaining amount of the polyfunctional (meth) acrylate-based compound Crosslinked (co) polymers. In a more specific example, as the multifunctional (meth) acrylate-based compound having a tri- or higher-functional (meth) acrylate group, a (meth) acrylate-based compound and / or 10 or more functional groups of 3 to 6 functional monomolecular forms Polyurethane-based polymers having a (meth) acrylate-based functional group, poly (meth) acrylic-based polymers or polyester-based polymers may be used together.

By the composition of such a binder, the difference in refractive index of the binder and the refractive index with the fine particles can be controlled to a more appropriate level. Moreover, it can contribute to maintaining the haze characteristic of the said glare-proof layer and an optical film at an appropriate level, and to improve image sharpness more. If only 3 to 6 functional monomolecular (meth) acrylate-based compounds are used, the haze characteristics may be out of an appropriate range, or the image sharpness may be lowered.

Examples of the monofunctional (meth) acrylate-based compound include a compound having a monomolecular form having 0-phenyl phenoxyethyl acrylate and one (meth) acrylate-based functional group and an aromatic ring, or hydroxy (meth) An acrylate compound etc. are mentioned.

Moreover, as a specific example of the said (3) -functional monomolecular-type (meth) acrylate type compound, the (meth) acrylate type of 3-6 molecular weights Compounds in the form of monomolecules having functional groups and aromatic rings (e.g., UA-306T, etc., used in the examples below), pentaerythritol, tri (meth) acrylate or trialkylpropanetri (meth) acrylate Etc. can be mentioned.

And as a polyurethane type polymer, a poly (meth) acrylic-type polymerizer, or a polyester type polymer which has the said (functional) acrylate-type functional group or more, the main chain of a polyurethane type polymer poly (meth) acrylic type polymer or polyester type polymer An average of 10 to 80, or an average of 10 to 50 (meth) acrylate-based functional groups are combined, the polymer may have a weight average molecular weight of 1000 to 200000. In addition, the (meth) acrylate type compound of the said 3-6 functional monomolecular form, and the polymer which has the (meth) acrylate type functional group of the said 10 functional or more, for example, increase by 1: 1-10: 1 Can be used as a ratio.

By using the above-described composition to obtain a binder in the form of a crosslinked (co) polymer, the refractive index of the binder is controlled to, for example, 1.50 to 1.60, or 1.50 to 1.56, or 1.51 to 1.55 in an appropriate range. It is possible to more effectively control the appropriate refractive index difference with each fine particle included in the layer, reduce the external reflection of the antiglare layer and the optical film, and further improve the haze characteristics and image sharpness.

In the anti-glare layer, on the other hand, one or more kinds of fine particles having a sub-micron scale dispersed on a binder, for example, micro particles of organic fine particles, and nano (nm) scale Inorganic fine particles are included. As each of the fine particles has a refractive index such that the absolute value of the difference in refractive index with the above-described binder is less than 0.15, the antiglare layer can exhibit low glossiness and excellent antiglare properties, and interference fringes derived from the base film can be reduced. Can be.

As the organic fine particles, all resin particles previously known to be usable in the antiglare layer and the like can be used without particular limitation, and specific examples thereof include polystyrene resin, poly (meth) acrylate resin or poly (meth) acrylate. Resin including -co-styrene-based copolymer resin Particulates are mentioned.

In addition, such organic fine particles are spherical particles having a particle size of 1 to 5 j¾ni, black to 1.5 to 1.5, or 1.5 to 1.57, or 1.53 to 1.57, or

It may be one having a refractive index of 1.54 to 1.56.

As the inorganic fine particles, metal oxide fine particles including silica, alumina, zirconia, or titania may be used. For example,

As spherical particles having a particle diameter of 10 nm to 300 nm, or 50 to 200 nm, from 1.4 to 1.75, black is from 1.4 to 1.65, or from 1.42 to 1.48, or from 1.42 to 1.

It may have a refractive index of 1.45.

Such one or more fine particles, for example, the organic and inorganic fine particles described above may be included in an amount of 0.1 to 10 parts by weight, and black to 0.2 to 8 parts by weight based on 100 parts by weight of the total weight of the antiglare layer.

In addition, the anti-glare layer may have a thickness of 1 to 10 μηι, or 2 to 8, and each of the above-described fine particles may be dispersed in the anti-glare layer, or may suppress reflection or scattering of the light by protruding at least a part thereof. .

The anti-glare layer formed with the above-described composition and thickness may have excellent anti-glare properties by properly suppressing reflection because it is scattering of external light, and exhibits excellent scratch resistance on the surface thereof, and effectively suppresses interference fringes derived from the base film. can do. The excellent optical properties of these antiglare layers can be defined by their low glossiness. For example, the antiglare layer has a 20 ^° glossiness of 50% to 70%, or 58% to 68%, or 59% to 66%,

60 ^° glossiness 75% to 90%, or 80% to 88%, or 83% to

It can be 87%.

On the other hand, the upper anti-glare layer may be formed by a composition comprising a photopolymerizable compound, a photoinitiator, and an organic solvent including a (meth) acrylate-based compound having a composition as described above.

In such compositions, conventionally known photoinitiators can be used as the photoinitiator without great limitation. Examples of the photoinitiator include 1-hydroxycyclonucleophenylphenyl ketone, benzyl dimethyl ketal, hydroxydimethylacetophenone, Single or a mixture of two or more selected from benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin butyl ether.

In this case, the photoinitiator may be added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the photopolymerizable compound of the (meth) acrylate compound. When the photoinitiator is included in less than 0.1 parts by weight based on 100 parts by weight of the photopolymerizable compound, sufficient photocuring may not occur due to ultraviolet irradiation, and when included in excess of 10 parts by weight based on 100 parts by weight of the photopolymerizable compound. The adhesion of the antiglare layer and the base film may be reduced. Furthermore, when the photoinitiator is included in an excessively large amount, by the reaction agent over time. The antiglare layer and the optical film including the same may exhibit yellowing, thereby deteriorating optical properties of the optical film.

In addition, the additive composition may further include an organic solvent. When such an organic solvent is added, there is no limitation in the constitution, but in view of securing the proper viscosity and final formation of the composition, the film strength of the film to be formed, the photopolymerizable compound

With respect to 100 parts by weight, preferably 50 to 700 parts by weight, more preferably ^. 100 to 500 parts by weight, most preferably 150 to 450 parts by weight can be used.

In this case, the use, but the kind of the organic solvent is _i Limited Castle obtain the _i, lower alcohols having a carbon number of 1 to 0.6, acetates, ketones, cellosolves, dimethylformamide, tetrahydrofuran, propylene glycol monomethyl ether One or more mixtures selected from the group consisting of, toluene and xylene can be used.

In this case, the lower alcohols may be exemplified by methanol, ethanol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, or diacetone alcohol. The acetates may be methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, or cellosolve acetate, and the ketones are methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, Or acetone may be used.

Meanwhile, the composition for forming an antiglare layer may further include at least one additive selected from the group consisting of a dispersant, a leveling agent, a wetting agent, an antifoaming agent, and an antistatic agent. In this case, the additive may be added in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the photopolymerizable compound, respectively.

The anti-glare layer may be formed by applying the above-described composition to one surface of a light-transmissive base film such as a polyester-based base film and proceeding drying and photocuring. Such drying and photocuring conditions may be formed in a general process of forming an anti-glare layer. Conditions may be varied and specific process conditions are also described in the following examples.

On the other hand, the optical film of the above-described embodiment may further include a primer layer formed between the base film and the antiglare layer, the primer layer having a refractive index smaller than the refractive index of the base film and larger than the binder of the antiglare layer. It is possible to further improve the adhesion between the base film and the antiglare layer by using such a primer layer. Furthermore, as the refractive index of the primer layer is adjusted to be smaller than the refractive index of the base film and larger than the antiglare layer, the difference in refractive index between adjacent layers is reduced, thereby further generating the interference fringe by the polyester base film. Can be reduced.

To this end, the primer charge may have a refractive index of 1.51 to 1.62, in order to achieve such a refractive index, a binder layer containing a polymer resin or an organic compound, and high refractive nanoparticles having a refractive index of 1.57 or more dispersed on the binder layer It may include. At this time, examples of applicable high refractive nanoparticles include titania ^' particles (Ti0 ₂ ), zirconia particles (Zr ₂ 0 ₃ ) or high refractive nano silica particles having a diameter of 200 nm or less, or a diameter of 10 to 200 nm. .

In addition, in order to suitably improve the adhesion between the antiglare layer and the base film, the primer worms do not inhibit the interference suppression effect (offset interference effect) according to the thickness of the antiglare layer, for example, 20 nm to 500 nm, or 30 nm to 500 nm, black may have a thickness of 30 to 300 nm. Except for the above-described matters related to the proper refractive index and thickness, the primer layer may be formed by applying the proper composition and process of the primer layer, which is conventionally applied to the optical film, and thus, further description thereof will be omitted. .

On the other hand, the optical film of the above-described embodiment may further include a low refractive layer formed on the anti-glare layer. The low refractive index layer may include a binder resin including a (co) polymer of a photopolymerizable compound and hollow silica particles dispersed in the binder resin.

By including such a low refractive layer, the reflection itself in the light-transmitting base film, such as the polyester-based base film can be reduced, as a result can further reduce the occurrence of interference fringes in the optical film of one embodiment. In addition, by using such a low refractive index layer, it is possible to reduce diffuse reflection on the display surface of the image display device to improve resolution and visibility.

The low refractive index layer may have a refractive index of 1.3 to 1.5 and have a thickness of 1 to 300 nm, for example, in order to effectively suppress reflection in the base film or diffuse reflection on the display surface of the display device. have.

On the other hand, the low refractive index layer may be formed from a photocurable coating composition for forming a low refractive index including a photopolymerizable compound and hollow silica: particles. Specifically, the low refractive index layer may contain a hollow silica ¾ dispersed in the binder resin and the binder resin containing a (co) polymer of the photopolymerizable compound. ^"

A photopolymerizable compound contained in the low refractive index layer can include a ^"monomer or oligomer containing (meth) acrylate or vinyl group. Specifically, the photopolymerizable compound may include a monomer or oligomer containing (meth) acrylate or vinyl group of one or more, two or more, or three or more.

As a specific example of the monomer or oligomer containing the said (meth) acrylate, a pentaerythri is tri (meth) acrylate, a pentaerythri (tetra) (meth) acrylate, and a dipentaerythritol is a penta (meth) acrylate ， Dipentaerythritol nucleated (meth) acrylate, tripentaereras to hepta (meth) acrylate, triylene diisocyanate, xylene diisocyanate nucleated methylene diisocyanate, trimethylolpropane tri (meth) acrylate, trimethylolpropane Polyethoxy tri (meth) acrylate, trimethyl propane trimethacrylate,. Ethylene glycol dimethacrylate, butanediol dimethacrylate, nuxaethyl methacrylate, butyl methacrylate or two or more kinds thereof, or urethane modified acrylate oligomers, epoxide acrylate oligomers, ether acrylate oligomers And a dendritic acrylate oligomer or a combination of two or more thereof. In this case, the molecular weight of the oligomer is preferably 1,000 to 10,000.

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

Meanwhile, the photocurable coating composition for forming the low refractive index layer may further include a fluorine-based compound including a photoreactive functional group. Accordingly, the binder resin of the low refractive index layer may include a crosslinked polymer between the photopolymerizable compound and the fluorine-based compound including the photoreactive functional group.

The bloso-based compound including the photoreactive functional group may include or replace one or more photoreactive functional groups, and the photoreactive functional group may participate in the polymerization reaction by irradiation of light, for example, by irradiation of visible light or ultraviolet light. Means functional groups. The photoreactive functional group may include various functional groups known to be able to participate in a polymerization reaction by irradiation of light, and specific examples thereof may include (meth) acrylate groups, epoxide groups, vinyl groups, or thiol groups ( Thi)).

The fluorine-based compound including the photoreactive functional group is 1 weight ⁰ /.

It can have a fluorine content of 25 weight ⁰ /. When the content of fluorine is too small in the fluorine-based compound including the photoreactive functional group, it may be difficult to sufficiently secure physical properties such as contamination resistance and alkali resistance of the low refractive index layer. In addition, when the content of fluorine in the fluorine-based compound including the photoreactive functional group is too large, surface properties such as scratch resistance of the low refractive index layer may be reduced. The fluorine-based compound including the photoreactive functional group may further include silicon or a silicon compound. That is, the fluorine-based compound including the photoreactive functional group may optionally contain a silicon or silicon compound therein.

The fluorine-based compound including the photoreactive functional group may have a weight average molecular weight (weight average molecular weight in terms of polystyrene measured by GPC method) of 2,000 to 200,000. If the weight average molecular weight of the fluorine-based compound including the photoreactive functional group is too small, the low refractive layer obtained from the photocurable coating composition of the embodiment may not have a layered alkali resistance. In addition, when the weight average molecular weight of the fluorine-based compound including the photoreactive functional group is too large, the low refractive index layer obtained from the photocurable coating composition of the embodiment may not have sufficient durability or scratch resistance. The photocurable coating composition may include 0.1 to 10 parts by weight of the fluorine-based compound including the photoreactive functional group based on 100 parts by weight of the photopolymerizable compound of the monomer or oligomer including the (meth) acrylate or vinyl group. When the fluorine-based compound including the photoreactive functional group is added in excess to the photopolymerizable compound, the coating property of the photocurable coating composition is reduced or the photocurable coating ^. The low refractive layer obtained from the composition may not have a layered durability or scratch resistance. Further, if the amount of the fluorine-based compound that contains the photopolymerizable compound than the photoreactive functional group is too small, the optical path may not have the sufficient alkali ^{"characteristic} low refractive index layer obtained from the conversion coating composition.

On the other hand, the above-mentioned hollow silica particles mean silica particles having a maximum diameter of less than 200 ran and having a void space on the surface and / or inside thereof. The hollow silica particles may have a diameter of 1 to 200 ηηι, or 10 to 100 nm.

As the hollow silica particles, hollow silica whose surface is coated with a fluorine compound alone, or whose surface is not coated with a fluorine compound, is used. It may be used in combination with the particles. Coating the surface of the hollow silica particles with a fluorine-based compound can lower the surface energy, thereby more uniform distribution of the hollow silica particles in the photocurable coating composition, the film obtained from the photocurable coating composition Durability and scratch resistance can be further improved.

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

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 jaylene; 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 may include 10 to 500 parts by weight, or 50 to 400 parts by weight of the hollow silica particles, based on 100 parts by weight of the photopolymerizable compound. If the hollow silica particles are added in an excess amount it is a ^"due scratch resistance and wear resistance of the coating film to decrease the content of the binder may decrease. In addition, when the hollow silica particles are added in a small amount, a uniform film formation of the hollow silica particles may not be achieved, and a desired effect may not be properly exhibited due to a high reflectance and a refractive index.

The photopolymerization initiator may be used without any limitation as long as it is a compound known to be used in the photocurable coating composition. Specifically, a benzophenone compound, acetophenone compound, biimidazole compound, triazine compound, or oxime compound Or two or more kinds thereof. 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.

Meanwhile, the photocurable coating composition may further include an organic solvent. Non-limiting examples of the organic solvent include ketones, alcohols, acetates and ethers, or a combination of two or more thereof. Specific examples of such organic solvents include ketones such as methyl ethyl kenone, methyl isobutyl ketone, acetylacetone or isobutyl ketone; Methane includes alcohols such as ethanol, n-propanol, i-propanol, n-butanol, i-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 may be included in the photocurable coating composition while being added at the time of mixing each component included in the photocurable coating composition or in the state in which each component is dispersed or mixed in the organic solvent. Meanwhile, . The low refractive layer included in the optical film of one embodiment can be obtained by applying the above-mentioned photocurable coating composition on the antiglare layer and drying and photocuring the applied resultant. This can follow the low refractive caterpillars specific process conditions are the conditions apparent to those skilled in the art, _and: Moro have been described in detail in the following embodiment, and thus ^pipe> further explanation will be omitted. ^ᅵ

Another example of the above-described optical film is a light-transmissive base film; And

An antiglare comprising a binder formed on the base film, the binder including a (meth) acrylate-based crosslinked polymer, and one or more fine particles having a sub-micron scale dispersed on the binder,

Optionally, it may further include a primer layer formed between the base film and the antiglare layer and a low refractive layer formed on the antiglare layer.

In addition, in such an optical film, the (meth) acrylate-based crosslinked polymer of the antiglare layer is 0 to 20 parts by weight of a monofunctional (meth) acrylate-based compound and trifunctional based on 100 parts by weight of the binder of the antiglare layer. It can be a crosslinked polymer of the above polyfunctional (meth) acrylate-based compound, the polyfunctional (meth) acrylate-based compound is a (meth) acrylate-based compound in the form of 3 to 6 functional monomolecular, 10 functional or more (Meth) acrylate type It may include a polyurethane-based polymer having a functional group, a poly (meth) acrylic polymer or a polyester-based polymer, the absolute value of the refractive index difference between the fine particles of the anti-glare layer and the binder may be less than 0.15.

As described above, such an optical film can effectively suppress excellent anti-glare properties, in particular, scattering or reflection of external light on the surface of an image display device. While it is possible to minimize the occurrence of interference fringes derived from the base film, it can exhibit excellent scratch resistance and the like. Moreover, the haze characteristic, image sharpness, etc. of an anti-glare layer and an optical film can further be improved. Therefore, such an optical film can be very preferably used in various image display devices.

. On the other hand, according to another embodiment of the invention, there is provided an image display device including the optical film described above.

An example of such an image display apparatus can be made as follows. The image display device includes a pair of polarizing plates facing each other; A thin film transistor, a color filter, and a liquid crystal cell sequentially stacked between the pair of polarizing plates; And a liquid crystal display device including a backlight unit, and the optical film of the above-described embodiment may be included in the image display surface side of the liquid crystal display device.

【Effects of the Invention】

According to the invention, excellent antiglare properties, in particular _i, hwaksang display device it can be suppressed effectively the ambient light scattered or reflected, standing ⁱ on the surface, to minimize the occurrence of gansip pattern derived from the base film, yet, excellent scratch An optical film that can exhibit excellent adhesion between the antiglare layer and the base film can be provided.

Such an optical film is preferably used in various image display devices, and can greatly improve the visibility and the like.

[Form for implementation of invention]

Specific embodiments of the invention are described in more detail in the following examples. However, the following examples are merely to illustrate specific embodiments of the invention, The content of specific embodiments of the invention is not limited by the following examples.

(1) Preparation of antiglare layer forming composition

The components of Table 1 were uniformly mixed to prepare a composition for forming an antiglare layer. The content of all components used in Table 1 is expressed in parts by weight.

TABLE 1

(1.43)

Initiator 1184 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Dispersant BYK300 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

IPA 33.2 22.1 33.1 22.2 33.0 32.8 33.2 Solvent

EtOH 33.2 66.0 44.2 33.2 44.2 33.0 33.0 33.2 Binder * 1.51 1.55 1.52 1.53 1.51 1.58 1.52 1.51 Organic Fine Particles

1.56 1.54 1.56 1.56 0 1.56 1.56 1.56 (Average)

Inorganic particulates

1.43 1.43 1.43 1.43 1.43 1.43 1.43 1.43 (Average)

Refractive index difference

Refractive index absolute

0.05 0.01 0.04 0.03 1.51 0.02 0.04 0.05 (Binder &

Organic particles)

Refractive index difference

Absolute value

0.08 0.12 0.09 0.10 0.08 0.15 0.09 0.08 (Binder &

Inorganic particles)

Total 00 100 100 100 100 100 100 100

^* The honey cutting rate of the binder is measured after crosslinking (co) polymerization according to the above composition and the preparation examples described later.

1) OPPEA: 0-phenylphenoxyethyl acrylate

2) HEA: 2-hydroxyethane acrylate

3) UA-306T (Kyoeisha): 6-functional acrylate compound formed by reacting two pentaerythriritriacrylates with toluene diisocyanate

4) Beamset 371 (ARAKAWA CHEMICAL):

Polyurethane / ester backbones with polymers of about 50 functional epoxy acrylate functional groups

5) 8BR-500 (TAISEI FINE CHEMICAL): A polymer in which a polyacryl main chain is bound to around 40 functional urethane acrylate functional groups.

6) TMPTA: trimethylolpropane triacrylate

7) PETA: Pentaerythritol triacrylate

8) I184 (lrgacure 184): photoinitiator, manufactured by Ciba.

9) BYK 300: PDMS dispersant

10) 103BQ (XX-103BQ, manufactured by Sekisui Plastic): Refractive index of 1.515 (about 1.52) _; PMMA-PS crosslinked copolymer fine particles with an average particle diameter of 2

1 1) 1 13BQ (XX-1 13BQ, manufactured by Sekisui Plastic): refractive index 1 .555 (about 1.56) _; PMMA-PS crosslinked copolymer fine particles having an average particle diameter of 2 μs

12) 3.5 μηι / 1 .555: spherical acrylic / styrene copolymer resin fine particles having a volume average particle diameter of 3 / and a refractive index of 1.555 (about 1.56) (XX-68BQ. Manufactured by Sekisui Plastic)

13) 9600A: spherical silica fine particles having a volume average particle diameter of 100 nm and a refractive index of 1.43 (X24-9600A; manufactured by Shinetsu)

14) MA-ST: Spherical silica fine particles with a volume average particle diameter of 12 nm and a refractive index of 43 (produced by Nissan Chemica)

Examples and Comparative Examples: Preparation of Optical Film

As shown in Table 2 below, a primer layer having a thickness of 100 nm is coated, and on the PET base film having a thickness of 100 and a refractive index of 1.6 to 1.7, the Preparation Examples 1 to 4 or Comparative Preparation Examples 1 to 3 After applying the anti-glare composition prepared in each and dried at 90 ° C. for 1 minute, the anti-glare layer was weed by irradiation with 150 mJ / cuf of ultraviolet light.

Experimental Example: Measurement of Physical Properties of Optical Film

The physical properties of the prepared optical film were measured according to the following method, which is shown together in Table 2 below. 1. Refractive Index Measurement

Refractive index of the binder, antiglare, etc. included in the optical film was measured by coating on the wafer using an ellipsometer, respectively. More specifically, the refractive index of the binder or the antiglare layer was applied to a 3 cm x 3 cm wafer, and the coating was performed using a spin coater (coating condition: 1500 rpm, 30 seconds), followed by drying at 90 ^° C for 2 minutes. And under ultraviolet purging, ultraviolet rays were irradiated under conditions of 180 mJ / cm ² . This formed each coating layer having a thickness of 100nm.

For this coating layer, a 70 ^° incidence angle was applied using a refractive index measuring apparatus (model name: M-2000) of A. Woollam Co., and linearly polarized light was measured in the wavelength range of 380 nm to 1000 nm. The measured linear light measurement data (ellipsometry data (Ψ, Δ)) was optimized to a MSE of 3 or less with a Cauchy model of the following general formula 1 using Complete EASE software.

, 、 B C

Λ Λ

In the above formula, η (λ) is the refractive index at the λ wavelength (300nm ~ 1800nm), A,

B, C, are Kosh parameters.

In addition, the refractive index of the base film and each fine particle used the information provided about a commercial item, 2. The evaluation of the interference fringe generation degree-the measurement of the rainbow stain generation degree / remin rainbow variation rate

In the optical films prepared in Examples and Comparative Examples, a black tape (Vinyl tape 472 Black, manufactured by 3M Co., Ltd.) was attached to prevent light from passing through the surface where the anti-glare layer was not formed, and then a reflection image was taken using a three wavelength light source. It was. The size of the captured image was 640 480 pixels (15cm x i 0cm), and the amount of light was adjusted to 70% of the maximum amount of light emitted from the three-wavelength lamp.

The presence of rainbow spots present on the surface of the optical film in the images used was evaluated according to the following criteria. The evaluation results are shown in Table 2 together. <Measurement standard>

0: No rainbow spots exist or rainbow intervals are 0.2 mm or less and no rainbows are observed in contrast to the complementary colors of red and green.

X: Rainbow interval is 0.2 mm or more, and rainbow is compared with the complementary color which is the same red and green. Rainbow is also visible in ordinary fluorescent light sources.

3. Overall / Internal Haze Rating

An optical film specimen of 4 cm × 4 cm was prepared and measured three times with a haze meter (HM-150, A light source, Murakamisa) to calculate an average value, which was calculated as the total haze value. The measurement, the transmittance JIS K 7361 standard, to rise was measured by ^"in JIS K 7105 standard. At the time of measuring internal haze, after attaching an adhesive film having a total haze of 0 to the coating surface of the optical film to be measured to make the surface irregularities flat, the internal haze was measured in the same manner as the above whole haze. 4. Gloss Rating

The glossiness of 20 ^° / 60 ^° was measured by using BYK Gardner's micro-TRI-gloss. Black tape _(3M) was attached to the surface where the coating layer of the base film was not formed during the measurement, and 20 ^° / 60 ^° glossiness was measured by changing the incident angle of light to 20 ^° / 60 ^° , respectively. The average value measured more than once was computed as each gloss value.

5. Scratch resistance evaluation

The optical film to be measured was cut into a width of 4 cm and a length of 15 cm and fixed to a scratch measuring instrument. After applying a constant load, the coated film was rubbed 10 times in a reciprocating manner to observe whether the surface was scratched. As the load was increased in units of 100 g, the maximum load without scratching was calculated as a result of the scratch resistance evaluation.

TABLE 2 Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Base Film PET PET PET PET PET PET PET PET Base Film 1.6-1.7 1.6-1.7 1.6-1.7 1.6-1.7 1.6- 1.7 1.6-1.7 1.6-1.7 Refractive index (birefringence) (birefringence) (birefringence) (birefringence) (birefringence) (birefringence) (birefringence) (birefringence) Comparative Manufacturing Comparative Manufacturing Comparative Manufacturing Comparison

Antiglare Layer Composition Manufacture Example 1 Manufacture Example 2. Preparation Example 3 Preparation Example 4 Example Example Example 1 Example 2

3 4 Formation of primer worm Formation formation Formation formation ¾ Formation primer layer

100 100 00 100 100 100 100 100 Thickness (nm)

Rainbow 0 0 0 0 X X X X Total Haze

3.2 2.7 2.5 2.8 1.2 2.8 2.2 5.2 (%)

Internal haze ^.

2.8 2.4 2.3 2.7 1 2.6 2 4.7 (%)

Glossiness (20 degrees) 60.5 65 61.8 59.8 72.5 56.5 72 39.2

73.5 Glossiness (60 degrees) 86 86.9 85.5 83.2 92.3 83.5 91.7 Scratch resistance

1200 1200 1500 1300 1300 200 900 1200 (9)

Referring to Table 2, it was confirmed that the optical film of the example not only suppresses the interference fringe (rainbow) derived from the base film, but also exhibits excellent optical properties such as low glossiness and haze, high scratch resistance, and the like.

However, in Comparative Examples 1 to 4, the monofunctional (meth) acrylate-based compound is used in an excessively high content in the formation of the binder, the difference in refractive index between the fine particles and the binder becomes 0.15 or more, or no compound of 10 or more functionalities is used. As the binder was formed, its scratch resistance or optical properties were lowered, or it was confirmed that the occurrence of interference fringes increased.

Claims

[Claim]

[Claim 1]

Polyester base film; And

An antiglare layer comprising a binder containing a (meth) acrylate-based crosslinked polymer, a micron () scale organic fine particle dispersed on the binder, and a nano (nm) scale inorganic fine particle dispersed on the binder; The (meth) acrylate crosslinked polymer may include 0 to 20 parts by weight of a monofunctional (meth) acrylate compound and a trifunctional or higher polyfunctional (meth) acrylate compound based on 100 parts by weight of the binder. It is a crosslinked polymer of

20 ^° glossiness of the surface of the antiglare layer is 50% to 70%, 60 ^° glossiness of 75% to 90%.

[Claim 2]

The optical film according to claim 1, wherein the polyester-based base film is a polyethylene terephthalate (PET) -based base film having a thickness of 30 to 20 (Γμηι.

[Claim 3]

The method of claim 1, wherein the polyfunctional (meth) acrylate compound is a (meth) acrylate compound of the monomolecular form of 3 to 6 functional,

An optical film comprising a polyurethane-based polymer, a poly (meth) acrylic-based polymer or a polyester-based polymer having 10 or more functional (meth) acrylate-based functional groups.

[Claim 4] The optical film of claim 1, wherein the binder has a refractive index of about 1.50 to about 1.60.

[Claim 5]

The optical film of claim 1, wherein the organic fine particles are resin fine particles including a polystyrene resin, a poly (meth) acrylate resin, or a poly (meth) acrylate-co-styrene copolymer resin.

[Claim 6]

The spherical particles as in, with the above organic fine particle is from 1 to 5 particle size comes to ^1,. An optical film having a refractive index of 1.5 to 1.57.

[Claim 7]

The optical film of claim 1, wherein the inorganic fine particles are metal oxide fine particles including silica, alumina, zirconia, or titania.

[Claim 8]

The optical film of claim 1, wherein the ^' inorganic fine particles are spherical particles having a particle diameter of 10 nm to 300 nm, and have a refractive index of 1.4 to 1.75.

[Claim 9]

The optical method of claim 1, wherein the organic and inorganic fine particles are included in an amount of 0.1 to 10 parts by weight, respectively, based on 100 parts by weight of the total weight of the antiglare layer.

3 a3 porn

ㅁ-

[Claim 10]

According to claim 1, wherein the anti-glare layer is an optical having a thickness of 1 to 10

Hi porn

Iii. ㅁ,

[Claim 11]

The optical film of claim 1, further comprising a primer layer formed between the base film and the antiglare layer, the primer layer being smaller than the refractive index of the base film and larger than the binder of the antiglare layer.

[Claim 12]

The optical film of claim 11, wherein the primer layer has a thickness of 20 nm to 500 nm.

[Claim 13]

The optical film according to claim 1, further comprising a binder resin formed on the antiglare layer and comprising a (co) polymer of a photopolymerizable compound and a low refractive layer containing hollow silica particles dispersed in the binder resin. .

[Claim 14]

The optical film of claim 13, wherein the low refractive index has a refractive index of 1.3 to 1.5 and a thickness of 1 to 300 nm.

[Claim 15]

Light-transmissive base film; And

A antiglare layer formed on the base film, the antiglare layer comprising a binder comprising a (meth) acrylate-based crosslinked polymer, and one or more fine particles having a sub-micron scale dispersed on the binder;

The (meth) acrylate-based crosslinked polymer may include 0 to 20 parts by weight of a monofunctional (meth) acrylate compound, a trifunctional or higher polyfunctional (meth) acrylate compound, based on 100 parts by weight of the binder of the antiglare layer. Crosslinked polymer,

The absolute value of the difference in refractive index between the fine particles and the binder of the antiglare layer is less than 0.15, The polyfunctional (meth) acrylate-based compound is a polyurethane-based polymer having a (meth) acrylate-based compound having a 3- to 6-functional monomolecular form and a (meth) acrylate-based functional group having 10 or more functional groups, and a poly (meth) acrylic-based compound. Optics Including Polymers or Polyester-Based Polymers

3ί porn

a σ ·

[Claim 16]

The optical film of claim 15, wherein the 20 ^° glossiness of the surface of the antiglare layer is 50% to 70%, and the 60 ^° glossiness is 75% to 90%.

[Claim 17]

An image display device comprising the optical film of claim 1.