JP2002371236A - Coating composition, its coating film, antireflection coating, antireflection film, and image display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition which is excellent in dispersibility, dispersion stability, storage stability, and applicability and can form a coating film having a low haze value and free from or resistant to the degradation caused by a photocatalytic action; a coating film, an antireflection coating, and an antireflection film formed from the composition; and an image display having the display surface covered with the antireflection coating. SOLUTION: This coating composition at least comprises (1) a finely particulate metal oxide having a primary diameter in the range of 0.01-0.1 μm, (2) a binder component curable with an ionizing radiation, (3) a dispersant having an anionic polar group, (4) an organic solvent, and (5) a zinc chelate compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition having excellent dispersibility, dispersion stability, and coating suitability, and a coating film formed using the coating composition. Specifically, a coating composition having improved light resistance, which is suitable for forming a layer constituting an antireflection film covering a display surface of an LCD, a CRT, or the like, particularly, a medium refractive index layer or a high refractive index layer. The present invention relates to an antireflection film having a coating layer formed using the coating composition, an antireflection film to which the antireflection film is applied, and an image display device.

[0002]

2. Description of the Related Art A display surface of an image display device such as a liquid crystal display (LCD) or a cathode ray tube display device (CRT) reflects light emitted from an external light source such as a fluorescent lamp in order to enhance its visibility. Less is required.

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 formed on the display surface of an image display device. It is known that the antireflection effect is improved by forming a low refractive index layer thereon.

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

[0005] In the case of the vapor phase method, it is possible to form a high-refractive index layer and a medium-refractive index layer of a high-performance and high-quality thin film, but it is necessary to precisely control the atmosphere in a high vacuum system. In addition, a special heating device or an ion generation accelerating device is required, which causes a problem that the manufacturing cost is inevitably increased because the manufacturing device is complicated and large. In addition, it is difficult to increase the area of the thin film of the high refractive index layer and the medium refractive index layer or to form the thin film to a uniform thickness on the surface of a film having a complicated shape.

[0006] On the other hand, when the spraying method is used as a coating method, there are problems such as poor utilization efficiency of the coating liquid and difficulty in controlling film forming conditions. When using a roll coating method, a gravure coating method, a slurry coating method, an immersion method, a screen printing method, or the like, the use efficiency of the film forming material is good, and there is an advantage in mass production and equipment cost, but there is a general advantage. In addition, there is a problem that the high refractive index layer and the medium refractive index layer obtained by the coating method are inferior in function and quality as compared with those obtained by the gas phase method.

In recent years, as a coating method capable of forming a thin film of a high refractive index layer and a medium refractive index layer having excellent quality, a metal oxide having a high refractive index such as titanium oxide or tin oxide in a solution of an organic binder is used. There has been proposed a method of applying a coating liquid in which fine particles are dispersed on a substrate to form a high refractive index coating film or a medium refractive index coating film.

[0008]

When a coating film is formed with the above-mentioned coating liquid containing the metal oxide fine particles having a high refractive index, the metal oxide fine particles having a high refractive index become photocatalytically actuated.
There is a problem that the coating film is deteriorated. In addition, when the solid components of such a coating liquid aggregate, there is a disadvantage that the haze value of the obtained coating film increases. Therefore, it is required that the coating films of the high refractive index layer and the medium refractive index layer do not deteriorate due to light. Further, the coating liquid for forming the high refractive index layer and the medium refractive index layer is required to have sufficient dispersibility in order to form a uniform coating film having a small haze value. Further, the coating liquid is required to have sufficient dispersion stability so that it can be easily stored for a long period of time. Further, the coating liquid is required to have a coating aptitude so that a large-area thin film can be easily formed from the viewpoint of mass production, which can be applied uniformly and thinly at the time of coating, and that drying unevenness does not occur. Can be

In view of the above technical requirements, an object of the present invention is to provide a coating composition having excellent dispersibility and dispersion stability of a coating solution, excellent storage stability, and excellent coating applicability. If the haze value is small, it can eliminate or suppress the deterioration due to photocatalysis, a coating composition,
An object of the present invention is to provide a coating film, an antireflection film, and an antireflection film formed using the coating composition, and further provide an image display device in which a display surface is covered with the antireflection film.

[0010]

The coating composition of the present invention for solving the above-mentioned problems comprises at least (1)
Metal oxide fine particles having a primary particle size in the range of 0.01 to 0.1 μm, (2) an ionizing radiation-curable binder component, (3) a dispersant having an anionic polar group, (4)
It is characterized by comprising an organic solvent and (5) a zinc chelate.

In the coating composition of the present invention, the embodiment in which the metal oxide fine particles and the zinc chelate coexist is at least (1) a metal oxide having a primary particle diameter in the range of 0.01 to 0.1 μm. (5) zinc chelate is added to a dispersion containing (2) an ionizing radiation-curable binder component, (3) a dispersant having an anionic polar group, and (4) an organic solvent. It is characterized by being prepared.

In the coating composition of the present invention, another embodiment of the coexistence of the metal oxide fine particles and the zinc chelate is as follows. Metal oxide fine particles having a primary particle diameter in the range of 0.1 μm, (2) an ionizing radiation-curable binder component, (3) a dispersant having an anionic polar group, and (4) an organic solvent. Features.

The coating composition of the present invention comprises titanium oxide (refractive index: 2.70), zirconium oxide (refractive index:
2.10), zinc oxide (refractive index: 1.95), tin oxide (refractive index: 2.00), cerium oxide (refractive index: 2.2)
0), antimony oxide (refractive index: 2.04), indium tin mixed oxide (refractive index: 1.95 to 2.00) and antimony tin mixed oxide (refractive index: 1.75 to 1.85)
Can be selected from the group of high-refractive-index metal oxide fine particles consisting of one or more of these. Since one or more of these are contained, by changing the type or amount of metal oxide fine particles, The refractive index of the film can be easily adjusted within a range from a medium refractive index to a high refractive index.

[0014] In the coating composition of the present invention,
Since the zinc chelate coexists with the metal oxide fine particles that increase the refractive index of the coating film, the photocatalytic action of the metal oxide fine particles is eliminated or suppressed by the zinc chelate,
When a coating film is formed, the deterioration of the coating film due to the photocatalytic action is eliminated or suppressed. Therefore, a decrease in the strength of the coating film due to the deterioration of the coating film of the binder component and a yellowing phenomenon are unlikely to occur.

Since the coating composition of the present invention contains a dispersant having an anionic polar group, it has excellent dispersibility and dispersion stability of the metal oxide fine particles, and has a refractive index of A transparent film having a small haze value adjusted to a medium to high refractive index can be formed, and the pot life is long.

Further, the coating composition of the present invention is excellent in coating suitability and can easily form a uniform large-area thin film.

The coating film of the present invention can be obtained by applying the coating composition of the present invention on the surface of a body to be coated and curing. The cured coating is a zinc chelate that reduces or eliminates photocatalytic activity, metal oxide fine particles having a primary particle size in the range of 0.01 to 0.1 μm, and a dispersant having an anionic polar group Are uniformly mixed in the cured binder.

This coating film has a high transparency, a small haze value, and the refractive index can be adjusted by controlling the amount of the metal oxide fine particles, so that one or more layers constituting the antireflection film can be formed. It can be suitably used as a light transmitting layer.

According to the present invention, the film thickness after curing is 0.05 to
When a coating film of 0.2 μm was formed, the refractive index was 1.55 to 1.55.
It is adjusted to the range of 2.00 and JIS-K7361-
The haze value measured in an integrated state with the substrate according to the provisions of 1 is not different from the haze value of the substrate alone, or the difference between the haze value of the substrate alone and the haze value can be suppressed to within 1%. is there.

The antireflection film of the present invention is formed by laminating two or more light transmissive layers having light transmissivity and different in refractive index from each other. It is a coating film.

The anti-reflection film of the present invention comprises at least one surface of a light-transmitting substrate film and two or more light-transmitting layers having light-transmitting properties and different refractive indices laminated on each other. At least one of the light transmitting layers is the coating film of the present invention.

The image display device of the present invention is an image display device in which the display surface is covered with an antireflection film, wherein the antireflection film has two light transmission layers having light transmittance and different refractive indexes from each other. It is characterized in that at least one of the light transmitting layers is the coating film of the present invention.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

Metal oxide fine particles Among the above essential components, metal oxide fine particles are a main component for adjusting the refractive index of a coating film formed using the coating composition of the present invention to a desired value. Each of the metal oxide fine particles described above has a high refractive index and is colorless or hardly colored, and thus 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 lower the transparency of the coating film. Here, “ultra-fine particles” are generally particles in the order of submicrons, and have a particle size smaller than particles having a particle size of several μm to several hundred μm which are generally called “fine particles”. Meaning small. That is, in the present invention, the metal oxide fine particles have a primary particle diameter of 0.01
A material having a thickness of not less than μm and not more than 0.1 μm, preferably not more than 0.03 μm is used. Average particle size is 0.0
If it is less than 1 μm, it is difficult to uniformly disperse it in the coating composition, and as a result, a coating film in which metal oxide fine particles are uniformly dispersed cannot be obtained. Further, those having an average particle diameter of more than 0.1 μm are not preferred because the transparency of the coating film is impaired.

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

As the metal oxide fine particles usable in the present invention, titanium oxide, zirconium oxide, zinc oxide, tin oxide, cerium oxide, antimony oxide, indium tin mixed oxide and antimony tin mixed oxide more or less have a photocatalytic activity. Therefore, when a coating film is formed using a coating composition containing only these metal oxide fine particles, the chemical bond between the binder resins forming the coating film by photocatalysis is broken, and the coating film strength is increased. And the haze value is liable to increase because the transparency of the coating film is lowered due to a decrease in the haze value. In the present invention, in order to eliminate such inconveniences, zinc chelates coexist in the metal oxide fine particles to reduce or eliminate the photocatalytic activity of the metal oxide fine particles.

A preferred method for coexisting a zinc chelate in the metal oxide fine particles is to add a zinc chelate to a dispersion liquid in which the metal oxide fine particles are dispersed in an organic solvent, and if necessary, adjust the pH and / or pH. Alternatively, there is a method in which a desired zinc chelate is physicochemically adsorbed on the surface of the metal oxide fine particles to coexist by changing the temperature conditions, or a method in which the metal oxide fine particles are coated with the zinc chelate. In order to coat the surface of the metal oxide fine particles with the zinc chelate, the zinc chelate is dissolved in an organic solvent, and after the metal oxide fine particles are dispersed in the solution, the organic solvent is completely evaporated and removed. By doing
Can be coated.

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.

Since the anionic polar group has a high affinity for the titanium oxide fine particles as described later in order to disperse the metal oxide fine particles, the addition of a dispersant having an anionic polar group makes it possible to disperse the metal oxide fine particles. Substance fine particles, particularly, titanium oxide fine particles can be efficiently dispersed.

[0031]Zinc chelate The zinc chelates that can be used in the present invention include zinc acetylene.
Ruacetonate Zn (CH_ThreeCOCHCOC
H_Three)_Two, Zinc benzoate Zn (C₆H_FiveCOO)_Two,
Zinc acetate Zn (CH_ThreeCOO)_Two, 2-ethylhexyl
Zinc acetate Zn (CH _Three(CH_Two)_ThreeCH (C
_TwoH_Five) COO)_TwoAnd the like.

Binder Component The ionizing radiation-curable binder component in the coating composition of the present invention is indispensable for imparting film formability to the coating composition of the present invention and adhesion to a substrate or an adjacent layer. It is blended as an ingredient. Since the ionizing radiation-curable binder component is present in the coating composition in the form of a monomer or oligomer that has not been polymerized, the coating composition has excellent coatability and is easy to 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 which causes a polymerization reaction directly by irradiation of ionizing radiation such as ultraviolet rays or electron beams or indirectly by the action of an initiator is used. Can be used. In the present invention, a radically polymerizable monomer or oligomer having an ethylenic double bond can be mainly used, and a photoinitiator is combined as needed. 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. A cationic photopolymerization initiator is used in combination with the cationic photopolymerizable binder component, if necessary. The monomer or oligomer as the binder component is preferably a polyfunctional binder component having two or more polymerizable functional groups so that cross-linking occurs between molecules of the binder component.

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

Of the ionizing radiation-curable binder components, it is preferable to use a binder component having a hydroxyl group remaining 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 titanium oxide in the coating composition and the coating film is improved, and the use amount of the dispersant is reduced. Since the dispersant does not function as a binder, the strength of the coating film can be improved by reducing the proportion of the dispersant.

As the binder component having a hydroxyl group remaining in the molecule, pentaerythritol polyfunctional (meth) acrylate or dipentaerythritol polyfunctional (meth) acrylate having a skeleton of the binder resin and having the hydroxyl group remaining in the molecule is used. 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)
Although acrylic acid is ester-bonded, a part of the hydroxyl group originally present in the molecule of pentaerythritol or dipentaerythritol is left 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 a high coating strength is 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, benzyldimethylketone, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2
-Methyl-1-phenylpropan-1-one, 1- (4
-Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, penzophenone and the like. Among them, 1-hydroxy-cyclohexyl-phenyl-ketone and 2-methyl-1 [4-
(Methylthio) phenyl] -2-morpholinopropan-1-one is preferably used in the present invention since it initiates and accelerates the polymerization reaction by irradiation with ionizing radiation even in a small amount. Any of these can be used alone or in combination of both. These are also present in commercial products, for example, 1-hydroxy-cyclohexyl-
Phenyl-ketone is Irgacure 184 (Irga
cure 184) from Nippon Ciba Geigy.

The dispersant having an anionic polar group has an anionic polar group having a high affinity for metal oxide fine particles, particularly, titanium oxide fine particles. 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 phosphate group, a hydroxyl group, and the like.

Specific examples of the dispersant having an anionic polar group include a product group supplied by Big Chemie Japan under the trade name of Dispervic, that is, Dispervik.
byk-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 and the like.

Among these, a molecular structure in which a side chain comprising 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, It is preferable to use a compound having a number average molecular weight of 2,000 to 20,000 because particularly good dispersibility can be obtained. The number average molecular weight can be measured by a GPC (gel permeation chromatography) method.
In order to meet such conditions, Disperbyk 163 (Disperbyk-
163).

Organic Solvent The organic solvent for dissolving and dispersing the solid components of the coating composition of the present invention is not particularly limited, and various organic solvents such as alcohols such as isopropyl alcohol, methanol and ethanol; methyl ethyl ketone and methyl isobutyl ketone And 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-based 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 the substrate, and the evaporation rate of the solvent after coating is not likely to cause uneven drying. A large-area coating film having a uniform thickness can be easily obtained. As a ketone solvent, a single solvent composed of one kind of ketone, a mixed solvent composed of two or more kinds of ketones, and one or more kinds of ketones containing other solvents and losing properties as a ketone solvent. None can be used. Preferably, 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 is used.

Using a ketone-based solvent as the organic solvent, the surface of the metal oxide fine particles was treated 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, the ethylene oxide-based dispersant as described above as a dispersant having an anionic polar group, that is, a side chain or an anionic having an anionic polar group in a main chain having a skeleton of an ethylene oxide chain. It has a molecular structure in which side chains having a polar group are bonded, and has a number average molecular weight of 2,000 to 2
It is more preferred to use a compound of 000.

Other Components The coating composition of the present invention contains , if necessary, a polymerization initiator of an ionizing radiation-curable binder component in addition to the above-mentioned essential components. Is also good. For example, if necessary, an ultraviolet shielding agent, an ultraviolet absorbing agent, a surface conditioner (leveling agent) and the like can be used.

The mixing ratio of each component can be appropriately adjusted, but generally, 4 to 20 parts by weight of the binder component and 10 to 10 parts by weight of titanium oxide, The dispersant having a group is mixed in a ratio of 4 to 10 parts by weight. However, when a binder component having a hydroxyl group remaining in the molecule is used, since the binder component acts as a dispersing aid, the amount of the dispersant having an anionic polar group can be significantly reduced. it can. The dispersant having an anionic polar group can be blended at a low ratio of 2 to 4 parts by weight. Since the dispersant does not function as a binder, the strength of the coating film can be improved by reducing the proportion of the dispersant.

When a photoinitiator is contained in the coating composition of the present invention, the photoinitiator can be added usually in an amount of 3 to 8 parts by weight based on 100 parts by weight of the binder component.

The amount of the organic solvent is appropriately adjusted so that each component can be uniformly dissolved and dispersed, does not cause agglomeration at the time of storage after preparation, and has a concentration not too dilute at the time of coating. Adjust. Prepare a high concentration coating composition by reducing the amount of solvent used within the range where this condition is satisfied,
It is preferable that the solution is stored in a state where the volume is not taken, and a necessary amount is taken out at the time of use and diluted to a concentration suitable for a coating operation.

The ratio of the organic solvent is 0.1% of the total solid content of the coating composition of the present invention when the total amount of the solid content and the organic solvent in the coating composition of the present invention is 100 parts by weight.
The organic solvent is used in an amount of 50 to 99.
It is preferable to mix at a ratio of 5 parts by weight, and more preferably, the total solid content of the coating composition of the present invention is 10 to 3 parts.
By using 70 to 90 parts by weight of the organic solvent with respect to 0 parts by weight, a coating composition having excellent dispersion stability and suitable for long-term storage can be obtained.

Preparation of Coating Composition In order to prepare the coating composition of the present invention using each of the above-mentioned components, dispersion treatment may be carried out according to a general method for preparing a coating solution. For example, a coating composition is 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, a bead mill, or the like. .

Characteristics of Coating Composition The thus obtained coating composition of the present invention has, as an essential component, a predetermined primary particle size, and a zinc chelate uniformly coexists with metal oxide fine particles. The preferable coexistence state includes a state in which the zinc chelate is physically and chemically adsorbed on the surface of the metal oxide fine particles and a state in which the metal oxide fine particles are coated with the zinc chelate. The coating composition of the present invention is such that the zinc chelate and metal oxide fine particles in the coexisting state are uniformly dispersed in a solution containing an ionizing radiation-curable binder component, a dispersant having an anionic polar group, and an organic solvent. Are distributed.

Therefore, the coating composition of the present invention is characterized in that the haze value is extremely small when formed into a coating film, since the metal oxide fine particles, which are factors inhibiting transparency, are uniformly dispersed. That is, the refractive index is adjusted by controlling the amount of the metal oxide fine particles in the coating composition of the present invention, and the coating composition is applied to the surface of an object to be coated such as a substrate, dried, and cured. Thereby, a coating film having a predetermined refractive index, high transparency, and a small haze value can be obtained. Therefore, the coating composition of the present invention is suitable for forming one or more layers constituting an antireflection film, and particularly, from the range of the refractive index which can be adjusted by changing the blending amount of the metal oxide fine particles. Considering this, it is suitable for forming a medium to high refractive index layer.

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

Furthermore, the coating composition of the present invention
It is excellent in coating aptitude, can be easily and thinly and widely and uniformly applied on the surface of a body to be coated, and can form a uniform large-area thin film. In particular, when a ketone-based solvent is used, the evaporation rate is moderate and unevenness in drying of the coating film hardly occurs, so that a uniform large-area thin film is particularly easily formed.

Applying the coating composition of the present invention to the surface of an object to be coated such as a substrate, drying and curing with ionizing radiation to form a substantially colorless and transparent coating film having a small haze value. Can be.

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

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

After the coating composition of the present invention is applied to a surface of a substrate such as a substrate in a desired coating amount, the coating composition is usually dried by heating with a heating means such as an oven, and then, ultraviolet rays or electron beams. A coating film is formed by radiating ionizing radiation such as that described above and curing.

Characteristics of Coating Film The coating film obtained as described above contains a zinc chelate as a substance for reducing or eliminating photocatalytic activity in the presence of metal oxide fine particles. Zinc chelates are physically adsorbed and coexist on the surface of the fine particles, or metal oxide fine particles are coated with the zinc chelates and coexist, and the zinc chelates in such a coexisting state, The metal oxide fine particles are uniformly dispersed in the cured coating film by the dispersant having an anionic polar group. Therefore, an increase in the haze value of the coating film can be suppressed.

The coating film of the present invention comprises an antireflection film 1
Or, it can be suitably used as two or more layers. In particular, considering the range of the refractive index that can be adjusted by changing the type and blending amount of the metal oxide ultrafine particles, forming the medium refractive index layer to the high refractive index layer 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 (light transmitting layers) having light transmittance and different refractive indexes from each other. Can be. 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 indexes. The layer having the refractive index is called a medium refractive index layer.

According to the present invention, the film thickness after curing is 0.05 to
When a coating film of 0.2 μm is formed, the refractive index is 1.55 to
Adjusted to the range of 2.00, and the haze value measured integrally with the substrate according to the provisions of JIS-K7361,
It is possible to keep the same haze value as that of the base material alone or to suppress the difference from the haze value of the base material only to within 1%.

Further, even if only a coating film of the present invention is provided on a surface coated with an antireflection film, for example, a display surface of an image display device, the refractive index of the coated surface itself and the refractive index of the coating film of the present invention can be improved. When 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 in some cases.

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

[0063] Application Example Figure 1 of the coating, which an example of a cross section of a liquid crystal display device 101 which covers the display surface by inclusive multilayered antireflection film coating of the present invention as a light transmitting layer shown schematically It is. The liquid crystal display device 101 prepares a color filter 4 in which an RGB pixel portion 2 (2R, 2G, 2B) and a black matrix layer 3 are formed on one surface of a glass substrate 1 on a display surface side, and a pixel of the color filter is prepared. The transparent electrode layer 5 is provided on the portion 2, the 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 arranged such that the transparent electrode layers 5 and 7 face each other. The gap is sealed with a sealing material 8, the liquid crystal L is sealed in the gap, an alignment film 9 is formed on the outer surface of the glass substrate 6 on the back side, and the glass substrate on the display surface side is formed. 1, a polarizing film 10 is attached to the outer surface, and a backlight unit 11
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. In the polarizing film 10 on the display surface side, a polarizing element 12 made of polyvinyl alcohol (PVA) or the like is coated on both sides with protective films 13 and 14 made of triacetyl cellulose (TAC) or the like, and an adhesive layer 15 is provided on the back side. A hard coat layer 16 and a multilayer antireflection film 17 are sequentially formed on the viewing side, and are adhered to the glass substrate 1 on the display surface side via an adhesive layer 15.

Here, in order to diffuse the light emitted from the inside of the liquid crystal display device and reduce glare, the surface of the hard coat layer 16 may be formed in an uneven shape, or the hard coat layer 16 may be made of an inorganic or inorganic material. An organic filler may be dispersed to serve as an antiglare layer (antiglare layer) having a function of scattering light inside the hard coat layer 16.

The portion of the multilayer type anti-reflection film 17 is formed on the middle refractive index layer 1 from the backlight unit 11 side toward the viewing side.
8, a high refractive index layer 19 and a low refractive index layer 20 are sequentially laminated. 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 laminated. When the surface of the hard coat layer 16 is formed in an uneven shape, the multilayer antireflection film 17 formed thereon is generally also formed in an uneven shape as shown in FIG.

The low refractive index layer 20 is formed using a coating film having a refractive index of 1.46 or less obtained from a coating liquid containing an inorganic substance such as silica or magnesium fluoride, a fluorine-based resin, or the like. be able to. The middle 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 middle refractive index layer 18 has a refractive index of 1.4.
A light transmitting layer having a refractive index of 1.65 or more is used for the light transmitting 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 reflection of the scenery and the fluorescent lamp is reduced, and the visibility of the display is improved. Further, since the hard coat layer 16 can also serve as a muffler layer, since the straight light from the inside and the external light are scattered, the glare of reflection is reduced, and the visibility of display is reduced. Further improve.

In the case of the liquid crystal display device 101, the coating composition of the present invention is 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 or more.
The medium refractive index layer 18 whose refractive index is adjusted to 1.80 and the high refractive index layer 19 whose refractive index is adjusted to 1.65 or more can be formed, and the low refractive index layer 20 can be further provided. Then, the polarizing film 10 including the multilayer antireflection film 17 is bonded to the adhesive layer 1.
5 can be attached to the glass substrate 1 on the viewing side.

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 an antireflection film. However, applying the coating composition of the present invention to the display surface of a CRT is a complicated operation. In such a case, an anti-reflection film containing the coating film of the present invention is prepared, and the anti-reflection film is formed by attaching the film to the display surface, so that the coating composition of the present invention is formed on the display surface. Need not be applied.

Two or more light-transmitting layers having light-transmitting properties and different in refractive index are laminated on one side or both sides of a light-transmitting substrate film, and at least one of the light-transmitting layers By forming one layer with the coating film of the present invention, an antireflection film can be obtained. The base film and the light transmission layer need to have a light transmittance that can be used as a material for the antireflection film, and are preferably as transparent as possible.

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

[0073]

EXAMPLES Example 1 Preparation of Coating Solution and Formation of Coating Film 1) Preparation of Titanium Oxide Dispersion As a high refractive index material, the content of rutile type titanium oxide is 79-8.
5%, surface treatment with Al ₂ O ₃ and stearic acid, primary particle size 0.01 to 0.03 μm, specific surface area 50 to 6
0 m ² / g, an oil absorption of 24 to 30 g / 100 g, and a water-repellent rutile type titanium oxide (TTO51 (C):
(Trade name, manufactured by Ishihara Sangyo Co., Ltd.). As an ionizing radiation curable binder component, pentaerythritol triacrylate (PET30: trade name, manufactured by Nippon Kayaku Co., Ltd.) was prepared. As a dispersant having an anionic polar group, a block copolymer having an affinity for a pigment (Dispervic 163: trade name, manufactured by BYK Japan KK) was prepared. As a photoinitiator, 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184: trade name, manufactured by Nippon Ciba Geigy) was prepared. Methyl isobutyl ketone was prepared as the organic solvent.

Rutile-type titanium oxide, pentaerythritol triacrylate, dispersant (Dispervic 16
3, brand name, manufactured by Big Chemie Japan), and
Put methyl isobutyl ketone in a mayonnaise bottle and use a paint shaker (trade name, Asada Tekko Co., Ltd.) using zirconia beads (φ0.3 mm) about 4 times the amount of the mixture as a medium.
), And a photoinitiator (Irgacure 184: trade name, manufactured by Nippon Ciba Geigy) was added after stirring to obtain a titanium oxide dispersion having the following composition. The composition of the obtained titanium oxide dispersion is as follows.

(Composition of Titanium Oxide Dispersion) Rutile Titanium Oxide: TTO51 (C) (trade name, manufactured by Ishihara Sangyo Co., Ltd.) 10 parts by weight Dispersant: Disperbyk 163 (trade name, manufactured by Big Chemie Japan Co., Ltd.) 2 parts by weight Photocurable resin: PET30 (trade name, manufactured by Nippon Kayaku Co., Ltd.) 4 parts by weight Photoinitiator: IRGACURE184 (trade name, manufactured by Nippon Ciba Geigy) 0.2 part by weight Solvent: MIBK (trade name, manufactured by Junsei Chemical Co., Ltd.) 37.3 parts by weight

2) Addition of Zinc Chelate Zinc acetylacetonate (manufactured by Matsumoto Kosho Co., Ltd.) was dissolved in methanol as a zinc chelate, and the resulting solution was added to titanium oxide in the titanium oxide dispersion by 10%.
% By weight (1 part by weight) was added to the titanium oxide dispersion and stirred with a stirrer for 30 minutes to obtain a coating composition.

3) Method of forming coating film The coating composition immediately after the preparation in the above-mentioned process was applied to a film having a thickness of 50
Coating with a bar coater # 2 on a μm surface-untreated TAC substrate (FT-T80UZ, trade name, manufactured by Fuji Film Co., Ltd.), and drying by heating at 60 ° C. for 1 minute, a UV irradiation device (Fusion UV Systems Japan) Using an H bulb (manufactured by Co., Ltd.) as a light source, the composition was cured at an irradiation amount of 500 mJ to form a transparent film having a thickness of 0.1 μm after curing.

The light resistance test of the obtained coating film was carried out by using a sunshine weather meter at a temperature of 63 ° C. under rainfall.
Time, 120 hours, about the coating film after 200 hours,
$ 200 steel wool, 200g load, 2
The steel wool resistance was evaluated by rubbing the surface 0 times. The results are shown in Table 1 below. According to Table 1, 10% by weight of zinc chelate was used based on titanium oxide.
It was confirmed that the addition improves the light resistance.

Example 2 Preparation of Coating Solution Zinc acetylacetonate (manufactured by Matsumoto Kosho Co., Ltd.) as a zinc chelate was dissolved in methanol so that the concentration became 5% by weight (0.5 part by weight) with respect to titanium oxide. After the liquid was adjusted, titanium oxide fine particles were added, and the mixture was stirred with a stirrer for 1 hour. After that, a heat treatment at 70 ° C. was performed in an oven to remove the solvent (methanol), and the methanol was completely removed to obtain titanium oxide fine particles coated with a zinc chelate. Thereafter, titanium oxide fine particles coated with the zinc chelate obtained in the above step were added to a composition in which a dispersant, a photocurable resin, a photoinitiator, and a solvent were blended to have the same composition as in Example 1, and the above-described procedure was performed. Using zirconia beads as a medium, the mixture was stirred for 10 hours using a paint shaker in the same manner as in Example 1. After the stirring, a photoinitiator was added to obtain a coating composition. The composition of the obtained coating composition is as follows.

Rutile-type titanium oxide: TTO51 (C) (trade name, manufactured by Ishihara Sangyo Co., Ltd.) 10 parts by weight Zinc acetylacetonate (trade name, manufactured by Matsumoto Kosho Co., Ltd.) 0.5 parts by weight Dispersant: Disperbyk 163 (trade name, BYK Chemie Co., Ltd.) Japan Co., Ltd.) 2 parts by weight Photocurable resin: PET30 (trade name, manufactured by Nippon Kayaku Co., Ltd.) 4 parts by weight Photoinitiator: IRGACURE184 (trade name, manufactured by Nippon Ciba Geigy Co., Ltd.) 0.2 parts by weight Solvent: MIBK (products) Name, manufactured by Junsei Chemical Co., Ltd.) 37.3 parts by weight

Preparation Method of Coating Film The coating composition immediately after the preparation in the above step was subjected to the same method as in Example 1 to obtain a 50 μm thick surface-untreated TAC substrate (FT-T80UZ, trade name, manufactured by Fuji Film Co., Ltd.). It was applied on the substrate to obtain a coating film of Example 2. The obtained coating film was subjected to a light resistance test in the same manner as in Example 1. The results obtained are shown in Table 1 below. According to Table 1, by coating the titanium oxide according to Example 2 with the zinc chelate, the amount of the zinc chelate is half that of the titanium oxide dispersion of Example 1 compared to simply adding the zinc chelate. It can be seen that the same effect was obtained.

[Comparative Example 1] The same as in Example 1 except that rutile-type titanium oxide surface-treated with stearic acid was used in order to ensure only dispersibility on the surface of titanium oxide, and no zinc chelate was used. In the same manner, a coating composition was prepared, and a coating film was formed using the coating composition in the same manner as in Example 1. The obtained coating film was subjected to a light resistance test in the same manner as in Example 1. The results obtained are shown in Table 1 below. According to Table 1, in the light resistance test of the obtained coating film, it deteriorated at 60 hours.

Comparative Example 2 For the purpose of suppressing the photocatalytic activity of titanium oxide, all of the above were used except that rutile-type titanium oxide surface-treated with Al ₂ O ₃ and stearic acid was used, and no zinc chelate was used. A coating composition was prepared in the same manner as in Example 1, and a coating film was formed using the coating composition in the same manner as in Example 1. The obtained coating film was subjected to a light resistance test in the same manner as in Example 1. The results obtained are shown in Table 1 below. According to Table 1, in the light resistance test of the obtained coating film, 60
Although the adhesion is maintained until the time, the deterioration after 120 hours becomes remarkable.

[0084]

[Table 1]

[0085]

The coating composition of the present invention has excellent dispersibility as a coating liquid, excellent dispersion stability, excellent storage stability, and excellent coating applicability. The formed coating film has a small haze value and can eliminate or suppress the deterioration of the coating film due to the photocatalytic action of the metal oxide fine particles added as the high refractive index fine particles. The coating film of the present invention can be suitably applied to an antireflection film and an antireflection film, and the present invention provides an antireflection film in which the deterioration of the coating film has been eliminated or suppressed, or an image display device using the antireflection film. Can be provided.

[Brief description of the drawings]

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

FIG. 2 schematically shows a cross section of a polarizing film 10 attached to an outer surface of a glass substrate 1 on a 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 a diagram schematically showing a cross section thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate on the display surface side 2 Pixel part 3 Black matrix layer 4 Color filter 5, 7 Transparent electrode layer 6 Glass substrate on the back side 8 Sealing material 9 Alignment film 10 Polarizing film 11 Backlight unit 12 Polarizing element 13, 14 Protective film DESCRIPTION OF SYMBOLS 15 Adhesive layer 16 Hard coat layer 17 Multilayer type antireflection film 18 Medium refractive index layer 19, 22 High refractive index layer 20, 23 Low refractive index layer 21 Base film 101 Liquid crystal display device 102 Antireflection film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 2/50 C08F 2/50 5G435 C09C 1/00 C09C 1/00 3/08 3/08 C09D 4/00 C09D 4/00 5/00 5/00 Z 7/12 7/12 171/00 171/00 201/02 201/02 G02B 1/11 G09F 9/00 313 G09F 9/00 313 G02B 1/10 A F term (Ref.) RA12 SA61 SA78 SA83 UA01 UA04 WA02 4J037 AA08 AA22 CB26 DD05 DD30 EE03 EE25 EE28 EE43 FF21 4J038 CE052 CG031 CG141 CG171 CH021 CH121 CH181 GA03 GA06 GA14 HA216 JA03 JA07 JA17 JA32 J A55 JC38 KA03 KA06 KA09 KA12 KA20 LA03 MA02 MA09 MA12 MA14 NA01 NA03 NA17 NA24 NA26 PA17 PB11 PC03 PC08 5G435 AA01 GG11 HH01 HH03 HH20 KK07

Claims (15)

[Claims] 1. At least (1) 0.01 to 0.1 μm
metal oxide fine particles having a primary particle diameter in the range of m
A coating composition comprising (2) an ionizing radiation-curable binder component, (3) a dispersant having an anionic polar group, (4) an organic solvent, and (5) a zinc chelate. 2. At least (1) 0.01 to 0.1 μm
metal oxide fine particles having a primary particle diameter in the range of m
(5) A zinc chelate is added to a dispersion containing (2) an ionizing radiation-curable binder component, (3) a dispersant having an anionic polar group, and (4) an organic solvent. A coating composition, characterized in that: 3. At least (1) metal oxide fine particles having a primary particle diameter in the range of 0.01 to 0.1 μm coated with a zinc chelate, (2) an ionizing radiation-curable binder component, 3) A coating composition comprising: a dispersant having an anionic polar group; and (4) an organic solvent. 4. The metal oxide fine particles include titanium oxide,
Zirconium oxide, zinc oxide, tin oxide, cerium oxide,
4. One or two or more metal oxide fine particles selected from the group of high refractive index metal oxide fine particles consisting of antimony oxide, indium tin mixed oxide and antimony tin mixed oxide. A coating composition as described. 5. The dispersant has a molecular structure in which a side chain comprising an anionic polar group or a side chain having an anionic polar group is bonded to a main chain having an ethylene oxide chain skeleton, and 4. The coating composition according to claim 1, wherein the compound has a molecular weight of 2,000 to 20,000. 6. The coating composition according to claim 1, wherein the binder component is a binder component having a hydroxyl group left in a molecule. 7. The binder component having a hydroxyl group remaining in the molecule is selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate.
7. The composition according to claim 6, which is a species or two or more components.
A coating composition as described. 8. The method according to claim 1, wherein the binder component is contained in an amount of 4 to 20 parts by weight and the dispersant is contained in an amount of 2 to 4 parts by weight based on 10 parts by weight of the metal oxide fine particles. 4. The coating composition according to 2, 3 or 4. 9. The coating composition according to claim 1, wherein the organic solvent is a ketone-based solvent. 10. A photoinitiator comprising 1-hydroxy-cyclohexyl-phenyl-ketone and / or 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one. The coating composition according to claim 1, 2 or 3, wherein: 11. The organic solvent may be used in an amount of 50 to 99.50 parts by weight based on 0.5 to 50 parts by weight of the total solid content of the coating composition.
4. The coating composition according to claim 1, wherein the coating composition is blended in an amount of 5 parts by weight. 12. A coating composition obtained according to any one of claims 1 to 11, which is obtained by applying the composition to a surface of an object to be coated and curing the composition, and having a thickness of 0.05 to 0.05 after curing.
At a time of 0.2 μm, the haze value measured in a state where the refractive index is 1.55 to 2.00 and integrated with the base material according to JIS-K7361-1 is different from the haze value of only the base material. A coating film having no or a difference from the haze value of only the substrate within 1%. 13. The light-transmitting layer according to claim 12, wherein two or more light-transmitting layers having a light-transmitting property and different refractive indexes are laminated. Characteristic anti-reflection film. 14. At least one surface of a light-transmitting base film is formed by laminating two or more light-transmitting layers having light-transmitting properties and having different refractive indexes from each other. An antireflection film, wherein at least one layer is the coating film according to claim 12. 15. An image display device comprising the coating film according to claim 12 applied to a surface of a liquid display device.