JP2003096400A - Coating composition, its coating film, antireflective membrane, antireflective film, image display device, and method for preparing coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating composition which excels in the dispersibility of a coating liquid even when fine particles of a metal oxide having a primary particle diameter of <=30 nm are used, and excels in transparency (a small haze value) when formed into a coating film, a coating film formed by using the coating composition, an antireflective membrane, an antireflective film, and a method for preparing the coating composition. SOLUTION: The coating composition comprises at least the fine particles of the metal oxide having the primary particle diameter of 1-30 nm, an ionization radiation curable binder component, a dispersing agent having an anionic polar group, an organic solvent, and a titanate based or aluminum based coupling agent. It is preferred that the components other than the coupling agent are firstly mixed to get compatible, and then the coupling agent is added to effect mixing.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating composition in which metal oxide fine particles having a primary particle diameter in the range of 1 to 30 nm are suppressed and dispersed, and particularly, a medium refractive index layer to a high refractive index layer. 1-30, suitable for forming layers
Coating composition realizing dispersibility of metal oxide fine particles having a primary particle size in the range of nm, antireflection film having a layer of a coating film excellent in transparency formed using the coating composition, and the reflection The present invention relates to an antireflection film to which an antireflection film is applied, an image display device, and a method for producing a coating composition.

[0002]

2. Description of the Related Art The display surface of an image display device such as a liquid crystal display (LCD) or a cathode ray tube display device (CRT) is provided with a reflection of a light beam emitted from an external light source such as a fluorescent lamp in order to enhance its visibility. It is required to be small.

It has been conventionally known that the reflectance is reduced by coating the surface of a transparent object with a transparent film having a small refractive index, and a high refractive index layer or a medium refractive index layer is provided on the display surface of an image display device. It is known that the antireflection effect is improved by forming a layer and further forming a low refractive index layer thereon.

The method of forming such a high refractive index layer or medium refractive index layer of the antireflection film is generally classified into a vapor phase method and a coating method. The vapor phase method includes a vacuum vapor deposition method and a sputtering method. There are a physical method and a chemical method such as a CVD method, and a coating method includes a roll coating method, a gravure coating method, a slide coating method, a spray method, a dipping method, and a screen printing method.

In the case of using the vapor phase method, it is possible to form a high-performance and high-quality thin film high-refractive index layer and medium-refractive index layer, but it is necessary to precisely control the atmosphere in a high vacuum system. Further, there is a problem that a special heating device or an ion generation accelerating device is required, which inevitably increases the manufacturing cost because the manufacturing device is complicated and large. Further, it is difficult to increase the area of the thin films of the high refractive index layer and the medium refractive index layer, or to form the thin films of uniform thickness on the surface of a film having a complicated shape.

On the other hand, in the case of using the spray method among the coating methods, there are problems that the utilization efficiency of the coating liquid is poor and it is difficult to control the film forming conditions. When the roll coating method, the gravure coating method, the slide coating method, the dipping method, the screen printing method and the like are used, the film forming raw materials are efficiently used and are advantageous in terms of mass production and equipment cost. The high refractive index layer and the medium refractive index layer obtained by the coating method are inferior in function and quality to those obtained by the vapor phase method.

In recent years, as a coating method capable of forming thin films of a high-refractive index layer and a medium-refractive index layer having excellent quality, metal oxides such as titanium oxide and tin oxide having a high refractive index are dissolved in a solution of a binder made of an organic substance. There is proposed a method of forming a high refractive index coating film or a medium refractive index coating film by coating a coating liquid in which fine particles are dispersed on a substrate.

[0008]

When a coating film is formed from a coating solution containing the above-described high-to-medium-refractive-index metal oxide fine particles, metal oxide fine particles having a particle diameter as small as possible are uniformly formed. It is desirable to use a dispersed coating solution in order to form a high-refractive index coating film or a medium-refractive index coating film having excellent transparency. However, the smaller the particle size of the metal oxide fine particles, the larger the interaction between particles and the more easily they aggregate in the coating liquid. Therefore, in particular, the metal oxide fine particles having a primary particle diameter of less than 30 nm are It was difficult to disperse inside.

The particle diameter of the metal oxide fine particles contained in the coating liquid for forming the coating film for the conventional high refractive index layer and medium refractive index layer is from 30 nm, which is in the range of good dispersibility. Since it is large, the obtained coating film has a problem in transparency, and particularly, the high refractive index layer and the medium refractive index layer, which are thick films having a thickness after curing of 0.2 to 10.0 μm, are transparent. There was a problem of low.

In view of the above problems, the object of the present invention is 30
A coating composition having excellent dispersibility of a coating solution even when using metal oxide fine particles having a primary particle size of nm or less and having excellent transparency (small haze value) when formed into a coating film, the coating composition An object of the present invention is to provide a method for producing a coating film, an antireflection film, an antireflection film and a coating composition formed by using the coating composition.

[0011]

[Means for Solving the Problems] The coating composition of the present invention for solving the above problems comprises at least (1)
Metal oxide fine particles having a primary particle diameter in the range of 1 to 30 nm, (2) an ionizing radiation-curable binder component,
(3) A dispersant having an anionic polar group, (4) an organic solvent, and (5) a titanate-based or aluminum-based coupling agent.

The coating film of the present invention obtained by applying the coating composition of the present invention to the surface of an article to be coated and curing it has a film thickness after curing of 0.2 to 10.0 μm, preferably 3. When the thickness is 0 to 8.0 μm, the refractive index is 1.60 to 2.
00, and the haze value specified in JIS-K7361-1 does not differ from the haze value of the substrate alone, or the difference from the haze value of the substrate alone is within 1%. It is a medium to high refractive index coating film excellent in

The antireflection film of the present invention is formed by laminating two or more light transmitting layers having light transmitting properties and different refractive indexes from each other, and at least one of the light transmitting layers has the medium refractive index or It is characterized by being a high refractive index coating film.

The antireflection film of the present invention comprises two or more light-transmitting layers having light-transmitting properties and different refractive indexes, which are laminated on at least one side of a light-transmitting substrate film. At least one of the light transmitting layers is a coating film having a medium to high refractive index according to the present invention.

The image display device of the present invention is characterized in that the display surface is covered with the antireflection film.

In the method for producing the coating composition of the present invention, (1) an ionizing radiation-curable binder component, a dispersant having an anionic polar group, an organic solvent, a titanate-based or aluminum-based coupling agent are mixed and stirred. Thus, a mixture in which the coupling agent and the binder component are well blended is formed, and (2) the metal oxide fine particles having a primary particle diameter in the range of 1 to 30 nm are added to and dispersed in the mixture.

In the coating composition of the present invention, the titanate-based or aluminum-based coupling agent serves to reduce the surface energy of the metal oxide fine particles and improve the wettability at the interface between the metal oxide fine particles and the binder resin. There is. Therefore, the titanate-based or aluminum-based coupling agent makes the surface of the metal oxide fine particles hydrophobic, strengthens the affinity with the interface with the binder resin, and improves the dispersibility of the metal oxide fine particles in the coating composition. As a result, the voids between the metal oxide fine particles and the binder resin are reduced, and the transparency of the obtained coating film is increased. When the coating film is used as an antireflection film, it becomes an antireflection film having high transparency. Further, the antireflection film provided with the antireflection film on at least one surface side of the base film having light transmittance becomes an antireflection film having high transparency. Further, the image display device whose display surface is covered with the antireflection film has a highly transparent display surface.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.

Metal Oxide Fine Particles Of the above essential components, the metal oxide fine particles are the main components for adjusting the refractive index of the coating film formed using the coating composition of the present invention to a desired value. Each of the above-mentioned metal oxide fine particles has a high refractive index of medium to high, and is colorless or scarcely colored, so that it is suitable as a component for adjusting the refractive index.

As the metal oxide fine particles, those having a so-called ultrafine particle size are used so as not to reduce the transparency of the coating film. The primary particle diameter of the metal oxide fine particles in the present invention is
1 to 30 nm. It is preferably 30 nm or less. If the average particle size is less than 1 nm, it is difficult to uniformly disperse it in the coating composition, and it becomes impossible to obtain a coating film in which the metal oxide fine particles are uniformly dispersed. Also, if the average particle size exceeds 30 nm,
It is not the object of the present invention as it impairs the transparency of the coating.

The primary particle size of the metal oxide fine particles may be visually measured by a scanning electron microscope (SEM) or the like,
Mechanical measurement may be performed by a particle size distribution meter or the like using a dynamic light scattering method or a static light scattering method. As long as the primary particle diameter of the metal oxide fine particles is within the above range, the particle shape can be spherical or needle-like, and any other shape can be used in the present invention.

Examples of the metal oxide fine particles usable in the present invention include titanium oxide, zirconium oxide, zinc oxide, tin oxide, cerium oxide, antimony oxide, indium tin mixed oxide and antimony tin mixed oxide.

Titanium oxide as a preferable example of the metal oxide fine particles includes rutile type, anatase type and amorphous type. In the present invention, rutile type titanium oxide has a higher refractive index than anatase type and amorphous type. Therefore, it can be preferably used.

Binder Component The ionizing radiation-curable binder component in the coating composition of the present invention imparts the coating composition of the present invention with functions such as film-forming property and adhesion to a substrate or an adjacent layer. Therefore, it is blended as an essential component. Since the ionizing radiation-curable binder component exists in the state of unpolymerized monomer or oligomer in the coating composition, it is excellent in coating suitability of the coating composition and can easily form a uniform large-area thin film. In addition, a sufficient coating film strength can be obtained by polymerizing and curing the binder component in the coating film after coating.

As the ionizing radiation-curable binder component, a monomer or oligomer having a functional group that directly or indirectly upon irradiation with ionizing radiation such as ultraviolet rays or electron beams causes a polymerization reaction by the action of an initiator is used. Can be used. In the present invention, a radical-polymerizable monomer or oligomer having an ethylenic double bond can be mainly used, and a photoinitiator is combined if necessary. However, it is also possible to use other ionizing radiation-curable binder components, for example, a photocationically polymerizable monomer or oligomer such as an epoxy group-containing compound may be used. If necessary, a cationic photopolymerization initiator is used in combination with the cationic photopolymerizable binder component. The monomer or oligomer serving as the binder component is preferably a polyfunctional binder component having two or more polymerizable functional groups so that cross-linking occurs between the molecules of the binder component.

Specific examples of the radically polymerizable monomer and oligomer having an ethylenic double bond include 2
-Monofunctional (hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, carboxypolycaprolactone acrylate, acrylic acid, methacrylic acid, acrylamide, etc. (Meth) acrylates; diacrylates such as pentaerythritol triacrylate, ethylene glycol diacrylate, pentaerythritol diacrylate monostearate; tri (meth) acrylates such as trimethylolpropane triacrylate, pentaerythritol triacrylate; pentaerythritol tetraacrylate derivatives and Polyfunctional (meth) acrylates such as dipentaerythritol pentaacrylate, or their radicals Le polymerizable monomer can be exemplified oligomers polymerized. Here, “(meth) acrylate” means acrylate and / or methacrylate.

Among the ionizing radiation-curable binder components, it is preferable to use a binder component having a hydroxyl group left in the molecule. Since the hydroxyl group is also an anionic polar group, the binder component has a high affinity for the metal oxide fine particles and acts as a dispersion aid. Therefore, when the binder component is used, the dispersibility of the metal oxide fine particles in the coating composition and the coating film is improved, and the amount of the dispersant used is reduced. Since the dispersant does not function as a binder, the coating strength can be improved by reducing the blending ratio of the dispersant.

As the binder component having a hydroxyl group left in the molecule, pentaerythritol polyfunctional (meth) acrylate or dipentaerythritol polyfunctional (meth) acrylate is used as the skeleton of the binder resin and a hydroxyl group is left in the molecule. Can be used. That is, such a binder component is composed of one molecule of pentaerythritol or dipentaerythritol and two or more molecules of (meth).
Acrylic acid is ester-bonded, but some of the hydroxyl groups originally present in the molecule of pentaerythritol or dipentaerythritol remain unesterified, and for example, pentaerythritol triacrylate can be exemplified. . Since pentaerythritol polyfunctional acrylate and dipentaerythritol polyfunctional acrylate have two or more ethylenic double bonds in one molecule, a cross-linking reaction occurs during polymerization, and high coating strength can be obtained.

Photoinitiator As a photoinitiator for initiating radical polymerization, for example,
1-hydroxy-cyclohexyl-phenyl-ketone,
2-Methyl-1 [4- (methylthio) phenyl] -2-
Morpholinopropan-1-one, benzyl dimethyl ketone, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2
-Methyl-1-phenylpropan-1-one, 1- (4
Examples include -isopropylphenyl) -2-hydroxy-2-methylpropan-1-one and benzophenone. Among these, 1-hydroxy-cyclohexyl-phenyl-ketone and 2-methyl-1 [4-
(Methylthio) phenyl] -2-morpholinopropan-1-one is preferably used in the present invention because even a small amount initiates and accelerates the polymerization reaction upon irradiation with ionizing radiation. These can be used alone or in combination of both. These also exist in commercial products, for example, 1-hydroxy-cyclohexyl-
Phenyl-ketone is available from Irgacure 184 (Irga
Cure 184) under the trade name of Cuba Geigy.

Dispersant The dispersant having an anionic polar group has an anionic polar group having a high affinity for the metal oxide fine particles, particularly titanium oxide fine particles. It is added in order to impart dispersibility to the metal oxide fine particles in the above. Examples of the anionic polar group include a carboxyl group, a phosphoric acid group, and a hydroxyl group.

As the dispersant having an anionic polar group, specifically, a product group supplied by Big Chemie Japan under the trade name of Disperbic, that is, Disper
byk-1 11, Disperbyk −110, Disperbyk −116, Dis
perbyk −140, Disperbyk −161, Disperbyk −162,
Disperbyk −163, Disperbyk −164, Disperbyk −170
, Disperbyk −171, Disperbyk −174, Disperbyk
-180, Disperbyk-182, etc. can be illustrated.

Among these, a main chain having an ethylene oxide chain skeleton has a molecular structure in which a side chain having an anionic polar group or a side chain having an anionic polar group as described above is bonded. , Number average molecular weight of 2,000
It is preferable to use a compound of from 20,000 to 20,000 because particularly good dispersibility is obtained. The number average molecular weight can be measured by the GPC (gel permeation chromatography) method. In order to meet such a condition, Disperbic 163 (Disperbic
byk-163).

Organic Solvent The organic solvent for dissolving and dispersing the solid component of the coating composition of the present invention is not particularly limited, and various ones, for example, alcohols such as isopropyl alcohol, methanol, ethanol; methyl ethyl ketone, methyl isobutyl ketone. , Ketones such as cyclohexanone; esters such as ethyl acetate and butyl acetate; halogenated hydrocarbons;
Aromatic hydrocarbons such as toluene and xylene; or mixtures thereof can be used.

In the present invention, it is preferable to use a ketone type organic solvent. When the coating composition of the present invention is prepared using a ketone-based solvent, it can be easily and uniformly applied to the surface of a substrate, and the evaporation rate of the solvent after application is moderate, and thus uneven drying is unlikely to occur. Therefore, a large-area coating film having a uniform thickness can be easily obtained. As the ketone-based solvent, a single solvent composed of one kind of ketone, a mixed solvent composed of two or more kinds of ketones, and another solvent together with one or more kinds of ketones are contained, and the property as a ketone solvent is lost. It is possible to use one that does not exist. It is preferable to use a ketone solvent in which 70% by weight or more, particularly 80% by weight or more, of the solvent is occupied by one or more ketones.

A ketone solvent is used as the organic solvent, and the surface of the metal oxide fine particles is mixed with the above-mentioned organic compound and / or
Alternatively, by coating with an organometallic compound, a coating composition having particularly excellent coating suitability can be obtained, and a uniform large-area thin film can be easily formed. Even in this case, an ethylene oxide-based dispersant as described above as a dispersant having an anionic polar group, that is, a main chain having a skeleton of an ethylene oxide chain, a side chain or an anionic polar group It is more preferable to use a compound having a molecular structure in which a side chain having a polar group of is bonded and having a number average molecular weight of 2,000 to 20,000.

Titanate or aluminum cups
Coupling agents titanate, general functions of the aluminum coupling agents, viscosity reduction of the metal oxide dispersion of the improved and the coating composition of the fine particles, the improvement of workability, highly filled of the metal oxide particles, the interface gap (Reduction of aggregates).

Examples of the titanate-based or aluminum-based coupling agent include carboxyl type, pyrophosphate type, phosphite type, and amino type coupling agents, which have the property of transitioning from hydrophobic to hydrophilic in this order. Which type of coupling agent is selected depends on the nature of the surface of the metal oxide fine particles (surface-treated product) to be used.

A coating composition containing a titanate-based or aluminum-based coupling agent is hydrolyzed to be used as a paint because it is released from the metal oxide fine particles due to hydrolysis and loses the dispersibility function when left standing for a long time in the presence of water. A slower one is desirable.

The titanate coupling agent has a hydrophilic group containing Ti that interacts with the metal oxide fine particles and a hydrophobic group that interacts with the resin or solvent matrix, and is, for example, manufactured by Ajinomoto Co., Inc. Product group provided by Titanate Coupling Agent Prenact under the trade name, namely KR-TTS, KR-46B, KR-5
5, KR-41B, KR-38S, KR-138S, K
R-238S, 338X, KR-44, and KR9SA are mentioned. For example, in the case of alkyl titanate, one having a long alkyl chain, one forming a stable complex, and one having a high molecular weight in the polymer are desirable.

As the aluminum-based coupling agent,
Aluminum isopropylate, mono sec-butoxy aluminum diisopropylate, aluminum sec
-Butyrate, aluminum ethylate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethylacetoacetate), alkylacetoacetate aluminum diisopropylate, aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum tris (acetylacetonate) , Aluminum = monoisopropoxy monooleoxyethyl acetoacetate, cyclic aluminum oxide isopropylate.

Other Components In addition to the above-mentioned essential components, the coating composition of the present invention contains a polymerization initiator as an ionizing radiation-curable binder component, if necessary, and further contains other components. Good. For example, if necessary, an ultraviolet shielding agent, an ultraviolet absorbing agent, a surface conditioner (leveling agent), etc. can be used.

Mixing ratio of each component In the coating composition of the present invention, it is desirable that the coupling agent is contained in an amount of 1 to 15% by weight, more preferably 3 to 10% by weight, based on the total solid content. If the amount of the coupling agent is less than 1% by weight, the coupling agent does not work effectively with respect to the binder component, so that the dispersibility is not improved. If the coupling agent exceeds 15% by weight, the coating film strength is reduced.

In the coating composition of the present invention, the organic solvent is 5 parts by weight based on 0.5 to 50 parts by weight of the total solid content.
It is desirable to be blended in a proportion of 0 to 99.5 parts by weight. When the organic solvent is less than 50% by weight, the pigment and the binder component cannot be stably and uniformly dispersed, and when the organic solvent exceeds 99.5% by weight, it does not make sense as a pigment dispersion liquid.

The metal oxide fine particles are 30% of the total solid content.
˜65 wt% is desirable. If it is 30% by weight or less, the desired refractive index cannot be reached, and if it is 65% by weight or more, it becomes difficult to obtain a stable dispersion liquid, and the mechanical strength when formed into a coating becomes weak.

The dispersant is preferably 10 to 20% by weight based on the total solid content. When it is 10% by weight or less, it becomes difficult to obtain a stable dispersion liquid, and when it is 20% by weight or more, the mechanical strength when formed into a coating becomes weak.

The binder component is 20 to 20 based on the total solid content.
60% by weight is desirable. If it is 20% by weight or less, the mechanical strength of the coating film becomes weak, and if it is 60% by weight or more, a desired refractive index cannot be obtained.

Preparation of Coating Liquid In order to prepare the coating composition of the present invention using the above components, dispersion treatment may be carried out according to a general method for preparing a coating liquid. For example, a coating composition can be obtained by mixing each essential component and each desired component in an arbitrary order, adding a medium such as beads to the obtained mixture, and appropriately dispersing the mixture with a paint shaker or a bead mill. .

A preferred method for producing the coating composition of the present invention is to mix and stir an ionizing radiation-curable binder component, a dispersant having an anionic polar group, an organic solvent, a titanate-based or aluminum-based coupling agent. A method of forming a mixture in which a coupling agent and a binder component are well blended, and then adding metal oxide fine particles having a primary particle diameter in the range of 1 to 30 nm to the mixture and dispersing the mixture to obtain a coating composition. .

Characteristics of Coating Composition The coating composition of the present invention thus obtained has, as an essential component, metal oxide fine particles having an extremely small primary particle size in the range of 1 to 30 nm, which are titanate-based or aluminum-based. The use of a system coupling agent enables uniform dispersion.

Therefore, the coating composition of the present invention has an extremely small primary particle size excellent in transparency, that is,
Since a coating composition is used in which metal oxide fine particles having a primary particle diameter in the range of 1 to 30 nm are used and in addition metal oxide fine particles which become a factor of impairing transparency are uniformly dispersed, The characteristic is that the haze value is extremely small. That is, the blending amount of the metal oxide fine particles in the coating composition of the present invention is controlled to adjust the refractive index, and the coating composition is applied to the surface of a substrate such as a substrate, dried and cured. As a result, a coating film having a predetermined refractive index, high transparency, and a small haze value can be obtained.

The coating composition of the present invention is suitable for forming one or more layers constituting an antireflection film, and in particular, it has a refractive index range that can be adjusted by changing the compounding amount of metal oxide fine particles. Considering from the above, it is suitable for forming the medium refractive index layer to the high refractive index layer.

Further, since the coating composition of the present invention is excellent in dispersion stability over a long period of time, it has a long pot life and is highly transparent even when used after being stored for a long period of time and has a small haze value. A film can be formed.

Further, the coating composition of the present invention comprises
It is excellent in coating suitability and can be easily and thinly and widely and uniformly applied to the surface of an object to be coated, and a uniform large-area thin film can be formed. In particular, when a ketone-based solvent is used, the evaporation rate is appropriate and the unevenness of the coating film is unlikely to occur, so that a uniform large-area thin film is particularly easy to form.

The coating composition of the present invention is applied to the surface of an article to be coated such as a substrate, dried, and cured by ionizing radiation to form a substantially colorless and transparent coating film having a small haze value. You can

Article to be coated The substrate to which the coating composition of the present invention is applied is not particularly limited. As a preferable substrate, for example, a glass plate,
Triacetate cellulose (TAC), polyethylene terephthalate (PET), diacetyl cellulose, acetate butyrate cellulose, polyether sulfone,
Acrylic resin, polyurethane resin, polyester,
Examples thereof include films formed of various resins such as polycarbonate, polysulfone, polyether, trimethylpentene, polyether ketone, and (meth) acrylonitrile. The thickness of the substrate is usually 25 μm to 100
It is about 0 μm.

Coating Film Forming Method The coating composition of the present invention is, for example, a spin coating method, a dipping method, a spraying method, a slide coating method, a bar coating method, a roll coater method, a meniscus coater method,
It can be applied onto the substrate by various methods such as a flexographic printing method, a screen printing method and a bead coater method.

The coating composition of the present invention is applied to the surface of an article to be coated such as a substrate in a desired coating amount, and then it is usually dried by heating with a heating means such as an oven, and then ultraviolet rays or an electron beam is applied. A coating film is formed by irradiating with ionizing radiation such as to cure.

Characteristics of coating film The coating film obtained as described above has finely dispersed metal oxide fine particles. Therefore, an increase in the haze value of the coating film can be suppressed.

The coating film of the present invention constitutes an antireflection film.
Alternatively, it can be preferably used as two or more layers, and in particular, in view of the range of the refractive index that can be adjusted by changing the type and blending amount of the ultrafine metal oxide particles, the medium refractive index layer to the high refractive index layer are formed. Suitable to do. The coating film of the present invention is used for forming at least one layer of a multilayer antireflection film formed by laminating two or more layers having light transmittance and different refractive indexes (light transmitting layers). You can In this specification, the layer having the highest refractive index in the multilayer antireflection film is referred to as a high refractive index layer, the layer having the lowest refractive index is referred to as a low refractive index layer, and other intermediate refractive index The layer having a refractive index is called a medium refractive index layer.

The cured coating film of the present invention has a thickness of 0.
Refractive index of 1.60 to 2.00 when 2-10.0 μm
And, the haze value measured in a state of being integrated with the base material according to the regulations of JIS-K7361 is not different from the haze value of the base material only, or the difference from the haze value of the base material is within 1%. It is possible to suppress.

Further, even if only one coating film of the present invention is provided on the surface coated with the antireflection film, for example, the display surface of the image display device, the refractive index of the coated surface itself and the refractive index of the coating film of the present invention are reduced. If the balance is just right, an antireflection effect can be obtained. Therefore, the coating film of the present invention may function effectively as a single-layer antireflection film.

The coating film of the present invention is particularly suitable for liquid crystal display devices (L
CD), cathode ray tube display (CRT), plasma display panel (PDP), electroluminescence display (ELD), and the like. It is preferably used for forming.

Application Example of Coating Film FIG. 1 schematically shows a cross section of an example of a liquid crystal display device 101 whose display surface is covered with a multilayer antireflection film containing the coating film of the present invention as a light transmitting layer. Is. The liquid crystal display device 101 prepares a color filter 4 formed by forming RGB pixel portions 2 (2R, 2G, 2B) and a black matrix layer 3 on one surface of the glass substrate 1 on the display surface side. The transparent electrode layer 5 is provided on the pixel portion 2,
A transparent electrode layer 7 is provided on one surface of the rear glass substrate 6, and the rear glass substrate 6 and the color filter 4 are opposed to each other with a predetermined gap so that the transparent electrode layers 5 and 7 face each other. The periphery is adhered with a sealing material 8, the liquid crystal L is sealed in the gap, the alignment film 9 is formed on the outer surface of the glass substrate 6 on the back side, and the polarizing film 10 is attached on the outer surface of the glass substrate 1 on the display surface side. Backlight unit 1 behind
1 is arranged.

FIG. 2 schematically shows a cross section of the polarizing film 10 attached to the outer surface of the glass substrate 1 on the display surface side. The polarizing film 10 includes a protective film 13 made of triacetyl cellulose (TAC) or the like on both sides of a polarizing element 12 made of polyvinyl alcohol (PVA) or the like.
14 is provided, an adhesive layer 15 is provided on the back side thereof, and a hard coat layer 16 and a multilayer antireflection film 17 are sequentially formed on the viewing side of the adhesive layer 15. It is attached to the glass substrate 1.

In order to diffuse the light emitted from the inside of the liquid crystal display device 101 and reduce the glare, the surface of the hard coat layer 16 is formed in an uneven shape, or the inside of the hard coat layer 16 is made of an inorganic or organic substance. It may also serve as an antiglare layer (antiglare layer) having a function of dispersing a filler to scatter light inside the hard coat layer 16.

The portion of the multilayer antireflection film 17 is the middle refractive index layer 1 from the backlight unit 11 side toward the viewing side.
8 has a three-layer structure in which a high refractive index layer 19 and a low refractive index layer 20 are sequentially stacked. The multilayer antireflection film 17 may have a two-layer structure in which a high refractive index layer 19 and a low refractive index layer 20 are sequentially stacked. When the surface of the hard coat layer 16 is formed in a concavo-convex shape, the multilayer antireflection film 17 formed thereon is also generally in a concavo-convex shape as shown in FIG.

The low refractive index layer 20 is formed by using a coating film having a refractive index of 1.46 or less obtained from a coating liquid containing an inorganic material such as silica or magnesium fluoride, a fluorine resin or the like. be able to. The medium refractive index layer 18 and the high refractive index layer 19 can be formed by coating the coating composition of the present invention, and the medium refractive index layer 18 has a refractive index of 1.4.
A light transmission layer having a refractive index of 1.65 or more is used for the light transmission layer in the range of 6 to 1.80 and the high refractive index layer 19.

By the action of the multilayer antireflection film 17,
Since the reflectance of the light emitted from the external light source is reduced, the scenery and the fluorescent lamp are less reflected and the visibility of the display is improved. Further, since the hard coat layer 16 can also serve as an antiglare layer, the glare of reflection is reduced and the visibility of the display is reduced because the straight traveling light and the external light from the inside are scattered. Further improve.

In the liquid crystal display device 101 shown in FIG. 1, the coating composition of the present invention was applied to a laminate composed of the polarizing element 12 and the protective films 13 and 14 to have a refractive index of 1.46.
It is possible to form the medium refractive index layer 18 adjusted in the range of 1.80 to 1.80, the high refractive index layer 19 adjusted to the refractive index of 1.65 or more, and further provide the low refractive index layer 20. Then, the polarizing film 10 including the multilayer antireflection film 17 is attached to the adhesive layer 1
It can be adhered to the glass substrate 1 on the display surface side via 5.

On the other hand, since the polarizing film 10 is not attached to the display surface of the CRT, it is necessary to directly provide the antireflection film. However, applying the coating composition of the present invention to the display surface of a CRT is a complicated task. In such a case, an antireflection film containing the coating film of the present invention is produced, and the antireflection film is formed by adhering it to the display surface. Therefore, the coating composition of the present invention is formed on the display surface. No need to apply.

At least one of the light-transmitting layers is formed by laminating two or more light-transmitting layers having light-transmitting properties and different refractive indexes on one surface or both surfaces of the light-transmitting substrate film. An antireflection film is obtained by forming one layer with the coating film of the present invention. The base film and the light-transmitting layer need to have a light-transmitting property such that they can be used as a material for the antireflection film, and those that are as transparent as possible are preferable.

FIG. 3 schematically shows a cross section of an example of the antireflection film 102 containing the coating film of the present invention. The antireflection film 102 has a high refractive index layer 22 formed by applying the coating composition of the present invention to one surface side of the base film 21 having light transmittance, and further having a low refractive index on the high refractive index layer 22. The rate layer 23 is provided. In this example, the light transmitting layers having different refractive indexes are the high refractive index layers 22.
Although only two layers of the low refractive index layer 23 and the low refractive index layer 23 are provided, three or more light transmitting layers may be provided. In that case, not only the high refractive index layer 22 but also the medium refractive index layer 23 can be formed by applying the coating composition of the present invention.

[0073]

[Example] [Example 1] Titania ultrafine particles having a primary particle diameter of 10 to 13 nm were titrated.
In the case of dispersion using a glass coupling agent 1) Preparation of titania ultrafine particle dispersion liquid Rutile titanium oxide was used as a metal oxide having a high refractive index. Surface treated with Al ₂ O ₃ , aluminum hydroxide and stearic acid, the content of rutile titanium oxide is 73%,
Primary particle size is 10 to 13 nm and specific surface area is 60 to 80 m ^2.
/ G, rutile-type titanium oxide (MT-0
1, manufactured by Teika Co., Ltd.) was prepared. As an ionizing radiation-curable binder component, pentaerythritol triacrylate (PET30: trade name, manufactured by Nippon Kayaku Co., Ltd.) was prepared.
As the dispersant having an anionic polar group, a block copolymer having an affinity for a pigment (Disperseick 16
3: product name, manufactured by Big Chemie Japan Co., Ltd.) was prepared. As a titanate coupling agent, tetranormal butyl titanate (Organix TA-25: trade name, manufactured by Matsumoto Kosho Co., Ltd.) was prepared. 1 as a photopolymerization agent
-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184: trade name, manufactured by Ciba-Geigy Japan) was prepared. Methyl isobutyl ketone was prepared as the organic solvent.

First, tetranormal butyl titanate,
Pentaerythritol triacrylate and a dispersant (Disperbic 163: trade name, manufactured by Big Chemie Japan Co., Ltd.) were added to methyl isobutyl ketone, and dissolved by stirring with a stirrer for 30 minutes.

Next, rutile titanium oxide was added to the solution obtained in the above step, and the mixture was placed in a mayonnaise bottle and about 4 parts of the mixture was added.
A double amount of zirconia beads (φ0.3 mm) was used as a medium and stirred with a paint shaker for 10 hours. After stirring, a photoinitiator (IRGAGUAR 184: trade name, manufactured by Ciba-Geigy Co., Ltd.) was added to give a coating composition having the following composition Obtained.

[0076] (Composition of coating composition) Rutile type titanium oxide: MT-01 (trade name, manufactured by Teika) 10 parts by weight Dispersant: Disperbic 163 (trade name, manufactured by Big Chemie Japan)                                                               2 parts by weight Photocurable resin: PET30 (trade name, manufactured by Nippon Kayaku Co., Ltd.) 4 parts by weight Titanate coupling agent: TA-25 (trade name, manufactured by Matsumoto Kosho Co.) 1.28 parts by weight Photoinitiator: IRGACURE 184 (trade name, manufactured by Nippon Ciba Geigy)                                                           0.2 parts by weight Methyl isobutyl ketone 17.48 parts by weight

2) Method for forming coating film The coating composition immediately after preparation obtained in the above step 1) was treated with a surface-untreated TAC substrate (FT-T8) having a thickness of 80 μm.
(0UZ: trade name, manufactured by Fuji Film Co., Ltd.) is coated with a bar coater # 16, heated and dried at 60 ° C. for 1 minute, and then UV.
Irradiator (Fusion UV Systems Japan Co., Ltd.)
(Manufactured by Hamamatsu Co., Ltd.) was used as a light source to cure at a dose of 500 mJ / cm ² to form a transparent film having a thickness of 8.0 μm after curing.

The film thickness after curing formed from each of the as-prepared coating compositions obtained in the above step 1) was 8.0.
The haze and the refractive index of the transparent film of μm were measured. The haze was measured using a turbidimeter NDH2000 (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.). The refractive index of the coating film after curing was measured using a spectroscopic ellipsometer (UVSEL: trade name, manufactured by Jobin-Evon Co.) at a wavelength of 633 nm of helium laser light.

The results are shown in Table 1 below. Example 1
According to the above, the coating composition of Example 1 had good dispersibility, and the transparency at the time of thick film was almost the same as that of the substrate, showing good results. The refractive index was 1.80.

[Comparative Example 1] Fine particles of titania were dispersed without a titanate coupling agent.
In that case, a coating film was formed in the same manner as in Example 1 except that the titanate coupling agent was not added. The results are shown in Table 1 below. According to Comparative Example 1,
The coating composition of Comparative Example 1 has poor dispersibility and easily gels.

Comparative Example 2 Dispersion of Titania Fine Particles with Large Particle Size As rutile type titanium oxide with a large particle size, rutile type titanium oxide having an average primary particle size of 50 nm was prepared. Rutile titanium oxide content is 85%, surface treated with Al ₂ O ₃ and zirconia, average primary particle size 50 nm, specific surface area 4
A rutile-type titanium oxide (MT-700HD: trade name, manufactured by Teika) having a hydrophilic surface of 0 to 60 m ² / g was prepared. The same binder, dispersant, and photoinitiator as those in Example 1 were used, and a coating film was formed in the same manner as in Example 1. The particle size of the rutile type titanium oxide used in the coating composition of Comparative Example 2 is within the range (1 to 1) of the present invention.
30 nm) and the surface energy is small,
It was possible to disperse without adding a titanate coupling agent when dispersing. The results are shown in Table 1 below. Comparative example 2
According to the above, the dispersibility is good, but the haze value when forming a thick film is high because the particle size is large. Since the titanium oxide content is high, the refractive index is higher than that of the first embodiment.

[0082]

[Table 1]

Example 2 The titania dispersion liquid obtained in Example 1 (coating)
When the composition) is used as a medium-refractive index hard coat layer, the titania dispersion liquid 1 having a refractive index of 1.80 obtained in Example 1 is obtained.
For 0 parts, 1 part of dipentaerythritol pentaacrylic paste (SR399E: trade name, manufactured by Nippon Kayaku Co., Ltd.)
A titania dispersion liquid having a refractive index of 1.76 was prepared.

8 μm of the above titania dispersion liquid on the TAC substrate
m, and after curing to a level where UV tack does not remain, a low-refractive-index layer having a refractive index of 1.40 made of a silicon-containing polyvinylidene fluoride copolymer is 90 nm on the obtained coating film.
It was possible to obtain an antireflection film having a reflectance of 0.4% at a wavelength of 550 nm at which human beings are most likely to feel glare, by coating it on and completely curing it with UV. This film has a pencil hardness of 2H.

Example 3 The titania dispersion obtained in Example 1 (coating
When the composition) is used as an antiglare layer having a high refractive index, an acrylic paste (pentaerythritol triacrylate / styrene beads having a particle diameter of 3.5 μm ) is added to the titania dispersion liquid having a refractive index of 1.80 obtained in Example 1 above. 6/4), cellulose acetate propionate (ethyl acetate solution,
Solid content 10%), toluene, photopolymerization initiator (IRGAC
URE651: trade name, manufactured by Ciba-Geigy Co., Ltd.) was added to prepare a matte hard coat material having a refractive index of 1.76 with a compounding ratio shown in Table 2 below.

The above matte hard coat material was applied on a TAC substrate in an amount of 5 μm and cured by UV to a level at which tack was not left, and then the resulting coating film had a refractive index of 1. containing a polyvinylidene fluoride copolymer containing silicon. 40 low refractive index layers 9
By coating to 0 nm and completely curing with UV, it was possible to obtain an antireflection film having a reflectance of 0.6% at a wavelength of 550 nm, which is most dazzling to human eyes. This film has a pencil hardness of 2H.

[0087]

[Table 2]

[0088]

The coating composition of the present invention is 1 to 3
Despite using the metal oxide fine particles having a primary particle diameter in the range of 0 nm, the coating liquid has excellent dispersibility, dispersion stability, storage stability, and coating suitability. The coating film formed using the coating composition of the present invention uses metal oxide fine particles having a primary particle diameter in the range of 1 to 30 nm, and thus has a small haze value.

In the present invention, the film thickness after curing is thick (0.2 to 1).
0.0 μm), the refractive index is 1.60 to 2.00
And, the haze value specified in JIS-K7361-1 does not differ from the haze value of the substrate alone, or the difference between the haze value of the substrate alone is 1% or less, and an excellent antireflection film having transparency, It is possible to provide an antireflection film or an image display device to which the antireflection film is applied.

[Brief description of drawings]

FIG. 1 is an example of a liquid crystal display device in which a display surface is covered with a multilayer antireflection film containing a coating film of the present invention as a light transmission layer, and a diagram schematically showing a cross section thereof.

FIG. 2 is a view schematically showing a cross section of a polarizing film attached to the outer surface of a glass substrate on the display surface side in the liquid crystal display device of FIG.

FIG. 3 is an example of an antireflection film including a coating film of the present invention, and is a diagram schematically showing a cross section thereof.

[Explanation of symbols]

1 Display side glass substrate 2 pixels 3 Black matrix layer 4 color filters 5,7 Transparent electrode layer 6 Glass substrate on the back side 8 Seal material 9 Alignment film 10 Polarizing film 11 Backlight unit 12 Polarizing element 13,14 Protective film 15 Adhesive layer 16 Hard coat layer 17 Multi-layer antireflection film 18 Middle refractive index layer 19, 22 High refractive index layer 20, 23 Low refractive index layer 21 Base film 101 liquid crystal display device 102 Anti-reflection film

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 5/00 C09D 5/00 Z 5G435 7/12 7/12 G02B 1/11 G03F 7/004 501 G03F 7 / 004 501 7/085 7/085 G09F 9/00 313 G09F 9/00 313 338 338 342 Z 342 H04N 5/72 A H04N 5/72 G02B 1/10 A F term (reference) 2H025 AA00 AB14 AC01 AD01 BC13 BC43 BC82 BC86 CA04 CA28 CB45 CC03 CC06 CC20 DA34 2K009 AA02 AA12 BB02 BB28 CC03 CC09 DD02 4F100 AA17B AA19B AA21B AA25B AA27B AA28B AA29B AA33B AH10B AJ06 AK25B AK54B AL05B AR00C AT00A BA03 BA07 BA10A BA10B CA30B DE01B EJ67B GB41 JA07B JB14B JN01 JN06 JN08C JN18 JN30 4J038 DF002 FA151 GA03 HA216 JA32 JC38 KA03 KA06 KA09 KA20 NA19 PA17 PB08 PB09 PC08 5C058 DA01 DA03 5G435 AA02 AA17 FF04 HH02 HH05 KK05 KK07

Claims (14)

[Claims] 1. A metal oxide fine particle having a primary particle diameter of at least (1) 1 to 30 nm, (2) an ionizing radiation-curable binder component, (3) a dispersant having an anionic polar group, A coating composition comprising (4) an organic solvent and (5) a titanate-based or aluminum-based coupling agent. 2. The metal oxide fine particles are titanium oxide,
Zirconium oxide, zinc oxide, tin oxide, cerium oxide,
The coating composition according to claim 1, wherein the coating composition is one or more selected from the group of high-refractive-index metal oxide fine particles composed of antimony oxide, indium tin mixed oxide, and antimony tin mixed oxide. 3. The dispersant has a molecular structure in which a side chain composed of an anionic polar group or a side chain having an anionic polar group is bonded to a main chain having a skeleton of an ethylene oxide chain, Average molecular weight of 2,000 to 20,000
The coating composition according to claim 1, which is a compound of 4. The coating composition according to claim 1, wherein the binder component is a binder component in which a hydroxyl group remains in the molecule. 5. The binder component having a hydroxyl group left in the molecule is selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. The coating composition according to claim 4, which is one or more components. 6. The coating composition according to claim 1, wherein the organic solvent is a ketone solvent. 7. The coating composition according to claim 1, wherein
As a photoinitiator, 1-hydroxy-cyclohexyl-phenyl-ketone and / or 2-methyl-1 [4-
A coating composition further comprising (methylthio) phenyl] -2-morpholinopropan-1-one. 8. The coating composition according to claim 1, wherein the Gappling agent is contained in an amount of 1 to 15% by weight based on the total solid content. 9. Total solids content of 0.5 in the coating composition.
50 to 99.5 parts by weight of the organic solvent.
The coating composition according to claim 1, wherein the coating composition is blended in a ratio of parts by weight. 10. A coating composition obtained by applying the coating composition according to claim 1 to a surface of a substrate to be coated and curing the coating composition, and having a film thickness after curing of 0.2 to 10.0.
Refractive index is 1.60 to 2.00 when μm, and JI
A coating film characterized in that the haze value specified in S-K7361-1 does not differ from the haze value of the substrate alone or the difference from the haze value of the substrate alone is within 1%. 11. The coating film according to claim 10, wherein two or more light transmitting layers having light transmitting properties and different refractive indexes are laminated, and at least one of the light transmitting layers is the coating film according to claim 10. Characteristic anti-reflection film. 12. A light-transmitting base film, comprising two or more light-transmitting layers having light-transmitting properties and different refractive indexes, which are laminated on at least one surface side of the light-transmitting substrate film. At least one is the coating film of Claim 10, The antireflection film characterized by the above-mentioned. 13. An image display device, wherein a display surface is covered with the antireflection film according to claim 11. 14. (1) An ionizing radiation-curable binder component, an anionic polar group-containing dispersant, an organic solvent,
A titanate-based or aluminum-based coupling agent is mixed and stirred to form a mixture in which the coupling agent and the binder component are well blended, and (2) the metal oxide fine particles having a primary particle diameter in the range of 1 to 30 nm A method for producing a coating composition, which comprises adding and dispersing.