JP2003041198A - High refractive coating composition, method for manufacturing the same, high refractive painted membrane, reflection preventive membrane, image- displaying device and reflection preventive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a painting material capable of forming a high-quality thin membrane having high refractive index, method for manufacturing the painting material, a painted membrane formed by using the painting material, a reflection preventive membrane using the painted membrane and an image- displaying device using the reflection preventive membrane. SOLUTION: A high refractive coating composition contains (a) super fine particles of metal oxide having an average particle size of 1-200 nm and a refractive index of >=1.60, (b) a complex formed by crosslinking molecules of a binder component having hydrogen bond forming groups via a metal compound and (c) a solvent. A high refractive painted membrane formed by using the coating composition is suitable for forming a layer, especially a high- refractive layer 19 which constitutes a reflection preventive membrane 17 of a monolayer-type or a multilayer-type.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating composition capable of easily forming a coating film having a high refractive index under low-temperature working conditions, a method for producing the coating composition, and the coating composition. Regarding coating film. More specifically,
A coating composition suitable for forming a layer constituting an antireflection film for covering a display surface such as LCD and CRT, particularly a high refractive index layer, a method for producing the same, a coating film formed by using the coating composition, The present invention relates to an antireflection film having a layer composed of the coating film, and an image display device and an antireflection film to which such an antireflection film is applied.

[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 known that the reflectance is reduced by coating the surface of a transparent object with a transparent film having a small refractive index. An antireflection film utilizing such a phenomenon is displayed on an image display device. It can be provided on the surface to improve the visibility. The antireflection film has a single-layer structure in which a low refractive index layer having a small refractive index is provided on the display surface, or a medium to high refractive index layer is formed on the display surface in order to further improve the antireflection effect. It has a multilayer structure in which a plurality of layers are provided and a low refractive index layer for reducing the refractive index of the outermost surface is provided on the middle to high refractive index layer.

When the above antireflection film or antistatic film is provided on a plastic whose surface is soft and is easily scratched, a hard coat layer is formed as a base on the substrate and the hard coat layer is used for reflection. It is desirable to provide an antistatic film or an antistatic film, but in this case, the hard coat layer is also required to have transparency.

Methods for forming a transparent thin film layer such as a high refractive index layer, a medium refractive index layer and a hard coat layer contained in such an antireflection film are generally classified into a vapor phase method and a coating method. Physical methods such as vacuum deposition method and sputtering method,
There is a chemical method such as a CVD method, and the coating method includes a spray method, a dipping method, and a screen printing method.

In the case of the vapor phase method, it is possible to form a highly functional and high quality transparent thin film, but it is necessary to control the atmosphere accurately in a high vacuum system, and a special heating device or ion There is a problem in that the generation acceleration device is required, and the manufacturing device is complicated and large in size, which inevitably increases the manufacturing cost. In addition, it is difficult to make the transparent thin film such as the high refractive index layer have a large area or have a complicated shape.

On the other hand, when the spray method is used among the coating methods, there are problems such that the utilization efficiency of the coating liquid is poor and it is difficult to control the film forming conditions. When the dipping method and the screen printing method are used, the efficiency of using the film-forming raw material is good, which is advantageous in terms of mass production and equipment cost.However, in general, the transparent thin film obtained by the coating method has a gas phase There is a problem that the function and quality are inferior to those obtained by the method.

In recent years, as a coating method capable of forming a high-refractive-index layer and a medium-refractive-index layer having excellent quality, fine particles of high-refractive index such as titanium oxide or tin oxide are dispersed in a solution of a binder made of an organic material. Apply the applied coating solution on the substrate,
A method of forming a coating film has been proposed.

Since it is essential that the coating film forming the medium to high refractive index layer is transparent in the visible light region, so-called ultrafine particles having a primary particle diameter of not more than the wavelength of visible light are used as the high refractive index fine particles. In addition to being used, it is necessary to uniformly disperse the high-refractive-index ultrafine particles in the coating liquid and the coating film. However, generally, as the particle size of the particles is reduced, the surface area of the particles increases, and the cohesive force between the particles increases. When the solid components of the coating liquid aggregate, the haze of the resulting coating film deteriorates. Therefore, the coating liquid for forming the thin films of the high refractive index layer and the medium refractive index layer is required to have sufficient dispersibility to form a uniform coating film with a small haze. Further, the coating liquid is required to have sufficient dispersion stability so that it can be easily stored for a long period of time. Therefore, there is a problem that the addition amount of the high refractive index ultrafine particles is limited.

The problem of agglomeration of ultrafine particles can be solved by using a dispersant having good dispersibility for the ultrafine particles. The dispersant is adsorbed on the surface of the fine particles while penetrating between the fine particles to be agglomerated, and enables the uniform dispersion in the solvent while loosening the agglomerated state during the dispersion treatment. However, since the surface area of the ultrafine particles is increased, a large amount of dispersant is required to uniformly disperse the ultrafine particles in the coating liquid and to stabilize the ultrafine particles to withstand long-term storage. When a large amount of a dispersant is added to the coating liquid, a large amount of the dispersant also exists in the coating film formed by using the coating liquid, the dispersant hinders the curing of the binder component, and the coating film strength is Extremely lower.

Further, from the viewpoint of mass production, a large-area thin film can be easily formed on the coating liquid so that the coating liquid can be uniformly thinly coated at the time of coating, and coating unevenness does not occur. Aptitude is required.

Further, a method has been proposed in which a hydrolyzate of a metal compound such as metal alkoxide is applied on a substrate to form a high refractive index thin film such as a titania thin film. Since a coating film formed from a hydrolyzate of a metal compound contains almost no organic matter, a coating film having a high refractive index can be easily obtained as compared with the coating film formed by using the dispersion liquid of the high refractive index ultrafine particles. . However, the service life of the coating liquid used in this method is short. Further, the coating film formed by this method has poor adhesion to the substrate and the thin film of the low refractive index layer, and there is also a problem that after the film is formed, it easily peels off at the boundary with the substrate and the low refractive index layer.

[0013]

The present invention has been accomplished in view of the above circumstances, and a first object thereof is to provide a coating material capable of forming a high quality thin film having a high refractive index. It is in. A second object of the present invention is to provide a coating film that is preferably used for forming an antireflection film. A third object of the present invention is to provide an antireflection film that is suitably applied to the display surface of an image display device. A fourth object of the present invention is to provide an image display device whose display surface is covered with such an antireflection film. The present invention is
Solve at least one of these objectives.

[0014]

The high refractive index coating composition according to the present invention comprises at least (a) ultrafine metal oxide particles having an average particle size of 1 to 200 nm and a refractive index of 1.60 or more, (b) ) A composite comprising a binder component having a hydrogen bond-forming group and having intermolecular crosslinking through a metal compound, and (c) a solvent.

The metal oxide ultrafine particles (a) are a main component for imparting a high refractive index to the high refractive index coating composition. Water is adsorbed on the surface of the metal oxide ultrafine particles to form a hydroxyl group, and the hydroxyl group forms a hydrogen bond with the hydrogen bond-forming group of the binder component. Therefore, the metal oxide ultrafine particles are uniformly dispersed in the binder. Disperses and has excellent dispersion stability.

Further, the metal compound replaces a part of the binder component to assist the film forming property, and also reduces the dilution effect of the metal oxide ultrafine particles (a) by the binder to improve the refractive index. It is an ingredient. That is,
In the coating composition, the metal compound is condensed in the state of a single molecule or in the state of a polycondensate with two or more binder components or with two or more binder molecules produced by polymerization of the binder components, Crosslinks are formed between the molecules of the binder. A metal compound is a reaction product (crosslinked structure, polycondensed structure) having a large refractive index and a high transparency by eliminating an organic group in such a crosslinking reaction and a polycondensation reaction to increase the content ratio of an inorganic component. Change to. Therefore, the high refractive index coating composition according to the present invention can form a coating film having a high refractive index as compared with the case where the metal compound is not mixed. At the same time, the metal compound or its polycondensate crosslinks between the molecules of the binder component or between the molecules of the binder produced by the polymerization of the binder component, and thus does not cause a decrease in the coating strength, rather the coating strength or The coating film hardness may be improved in some cases.
Therefore, the high refractive index coating composition according to the present invention,
It is possible to form a coating film having a coating strength equal to or higher than that in the case where the metal compound is not mixed.

When the binder component and the metal compound are present in the coating composition in separate forms that are not a complex, the binder component and the metal compound are present in the coating composition or the coating film thereof. When the and are crosslinked, the distribution of the metal compound may not be sufficiently uniform. In particular, when a metal compound capable of being hydrolyzed and polycondensed is blended in the coating composition and the metal compound in the coating composition or the coating film is hydrolyzed, crosslinking between the binder component and the metal compound is performed. Since the polycondensation reaction between the metal compounds proceeds more predominantly than the bonding, the polycondensate of the metal compound pushes away the binder component and easily aggregates, resulting in a decrease in optical uniformity and film strength.

On the other hand, in the present invention, the binder component and the metal compound are allowed to exist in the coating composition in the form of a complex in which the molecules of the binder component are cross-linked through the metal compound. Since the metal compound can be fixed in a state of being uniformly distributed in the binder component and the aggregation of the metal compound or its polycondensate can be prevented, the uniformity of the coating composition and the coating prepared using the coating composition. The optical uniformity and film strength of the film can be sufficiently improved.

It is preferable that the metal compound is capable of forming a cross-linking bond between the molecules of the binder component and capable of polycondensation between the metal compounds because the coating film strength is improved. Further, when the metal compound forming the composite is partially hydrolyzed and / or polycondensed between the metal compounds, the reactivity of the coating composition is high, and therefore, after forming a coating film. The polycondensation reaction can be carried out in a short time with a small amount of energy, and the productivity of the coating film can be improved.

As the metal compound capable of undergoing polycondensation itself, a compound selected from the group consisting of alkoxides having two or more alkoxyl groups directly bonded to a metal atom, and chelated products thereof can be used. Particularly preferred is a metal compound selected from the group consisting of titanium alkoxides, zirconium alkoxides, silicon alkoxides, silane coupling agents, and chelate products thereof. The alkoxide having two or more alkoxyl groups also has an action of selectively adsorbing to the metal oxide ultrafine particles to improve the dispersibility and stability of the ultrafine particles.

As the chelating agent for forming the chelate, a compound selected from the group consisting of alkanolamines, glycols, acetylacetone, and ethyl acetoacetate each having a molecular weight of 10,000 or less. Can be used.

It is preferable that the chelate compound contains a chelating agent in an amount of 0.1 to 2 mol per mol of the metal atom of the metal compound.

The hydrogen bond-forming group of the binder component is
It is also preferably a functional group capable of forming a cross-linkage with the metal compound. As the functional group that is a hydrogen bond-forming group and can also form a cross-linking bond with a metal compound, for example, a hydroxyl group can be mentioned.

At least a part of the binder component is
A compound having two or more polymerizable groups in one molecule is preferable. Bifunctional or higher functional compound as a binder component,
In particular, by using a polyfunctional monomer or oligomer, the binder molecules are directly crosslinked in addition to being crosslinked through the metal compound or a condensate thereof, so that the coating film strength is improved. The binder component may be a photocurable compound having a photopolymerizable group.

The above-mentioned complex has a reaction equivalence ratio of an alkoxide having at least two alkoxyl groups directly bonded to a metal atom or a chelate thereof (b2) to a binder component (b1) having a hydroxyl group as a hydrogen bond-forming group. (B
It is preferable that 2 / b1) is crosslinked at a ratio of 1 or less, because aggregation of a polycondensate of alkoxides is small.

In the high refractive index coating composition of the present invention, 10 to 95% by weight of the metal oxide ultrafine particles and 5 to 5% of the composite are essential components with respect to the total weight of the components excluding the solvent. It is preferably contained in a ratio of 90 and optionally other components.

The high refractive index coating composition of the present invention comprises
It is preferable that the gel fraction when applied at a coating amount of 0.2 g / m ² and heated at 120 ° C. for 2 minutes is 10% or more. When the gel fraction is 10% or more, it can be said that a sufficient amount of cross-linking bonds are formed between the molecules of the binder component through the metal compound or its polycondensate, and thus the coating film strength is insufficient. Does not happen.

Next, the first method for producing the high refractive index coating composition according to the present invention is the alkoxyl group directly bonded to a metal atom for the binder component (b1) having a hydroxyl group as a hydrogen bond forming group. An alkoxide or a chelate thereof (b2) having two or more of
After the polycondensation reaction is restricted to 1 or less with 2 / b1) to form a complex in which the molecules of the binder component having a hydrogen bond-forming group are crosslinked through a metal compound,
At least (a) an average particle diameter of 1 to 200 nm and a refractive index of 1.60 or more, ultrafine metal oxide particles, (b) the composite, and (c) a solvent are mixed.

The second method for producing a high-refractive index coating composition according to the present invention comprises at least (a) ultrafine metal oxide particles having an average particle size of 1 to 200 nm and a refractive index of 1.60 or more, ( b1) a binder component having a hydroxyl group as a hydrogen bond-forming group, and (b2) an alkoxide having at least two alkoxyl groups directly bonded to a metal atom or a chelate thereof at a reaction equivalent ratio (b2 / b1) to the binder component. Having a hydrogen bond-forming group by polycondensing the binder component and the metal compound or its chelate in the mixture after preparing a mixture by mixing an amount of 1 or less and (c) a solvent. It is characterized by forming a complex in which the molecules of the binder component are crosslinked through a metal compound.

The first high refractive index coating film according to the present invention is obtained by applying the above-mentioned high refractive index coating composition onto the surface of an article to be coated.

The second high refractive index coating film according to the present invention has an average particle size of 1 to 200 nm in a binder obtained by crosslinking a polymer having a hydrogen bond forming group with a metal compound or a polycondensate thereof. It is characterized in that ultrafine metal oxide particles having a refractive index of 1.60 or more are dispersed.

These first and second high-refractive-index coating films can be formed by using the high-refractive-index coating composition according to the present invention, and have good adhesion to a substrate or a low-refractive-index layer. Is favorable, has excellent coating strength, has a high refractive index, is substantially transparent, and can be suitably used as a layer constituting the antireflection film, particularly as a medium to high refractive index layer and a high refractive index hard coat layer. .

Further, in the high refractive index coating film according to the present invention, the tensile strength of the coating film can be significantly improved by forming a cross-linking bond in a state where the metal compound is uniformly distributed between the binder components. it can. Specifically, using the above high refractive index coating composition according to the present invention, JIS K7
When a test piece of a coating film was prepared based on 113 and a breaking strength was measured by a tensile test, a coating composition having a composition obtained by removing a metal compound from the high refractive index coating composition was used as a comparative sample. It is possible to obtain a breaking strength value of 1.3 times or more of the breaking strength measured by performing a tensile test.

The high refractive index coating film according to the present invention can have a refractive index of 1.65 or more. In addition, the high refractive index coating film according to the present invention has a high refractive index of 0.
After coating and curing to a final film thickness of 1 μm, JIS K
The hardness of the coating film measured by a pencil hardness test based on 5600 under a load of 1 kg can be H or higher.

The antireflection film according to the present invention is formed by laminating two or more light transmitting layers having light transmitting properties and different refractive indexes, and at least one of the light transmitting layers is according to the present invention. It is characterized in that it is the high refractive index coating film.

A material having a lower refractive index than that of the high refractive index coating film according to the present invention is applied or laminated by a film forming method such as vacuum film forming such as vapor deposition to form a low refractive index layer. When forming the adjacent layer of, the high refractive index coating film according to the present invention,
Good adhesion is exhibited with respect to the adjacent layer formed by either method. The high-refractive-index coating film according to the present invention exhibits good adhesion to an adjacent layer such as a coating film or a vapor deposition film by the action of a hydrogen bond-forming group of a binder component, and an inorganic bond composed of an inorganic metal. Conceivable.

The present invention provides an image display device and an antireflection film to which the antireflection film of the present invention is applied.

An image display device according to the present invention is an image display device in which a display surface is covered with an antireflection film, wherein the antireflection film has light transmitting layers having light transmitting properties and different refractive indexes from each other. Two or more layers are laminated, and at least one of the light transmitting layers is the high refractive index coating film according to the present invention.

The antireflection film according to the present invention is
On one surface side of the base film having a light-transmitting property, two or more light-transmitting layers having a light-transmitting property and different refractive indexes are laminated, and at least one of the light-transmitting layers is used in the present invention. It is characterized in that it is the above-mentioned high refractive index coating film.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. In the present specification, the coating composition according to the present invention, and the coating film according to the present invention are referred to as "high refractive index coating composition" and "high refractive index coating film", respectively. Only such expressions are used for convenience of explanation of the invention, and the scope of the coating composition and the coating film which belong to the present invention is not limited by the term “high refractive index”.

Further, in the present specification, "(meth) acryloyl" means acryloyl and methacryloyl,
“(Meth) acrylate” means acrylate and methacrylate, and “(meth) acrylic” means acrylic and methacrylic.

The high refractive index coating composition according to the present invention has at least the following essential components: (a) An average particle size of 1 to 200 nm and a refractive index of 1.60.
A coating material comprising the above metal oxide ultrafine particles, (b) a complex in which the molecules of a binder component having a hydrogen bond-forming group are crosslinked through a metal compound, and (c) a solvent. Depending on, it may contain other ingredients.

Since the high refractive index coating composition of the present invention can form a coating film having a high refractive index, at least one of the layers constituting the single-layer type antireflection film or the multilayer type antireflection film is formed. It can be suitably used for forming, and is particularly suitable for forming a middle or high refractive index layer and a high refractive index hard coat layer of a multilayer antireflection film.

Among the above essential components, the metal oxide ultrafine particles (a) are the main components for imparting a high refractive index to the high refractive index coating composition. Since the metal oxide is colorless or hardly colored, those having a high refractive index are suitable as a component for imparting a high refractive index to the coating film. The reason why the so-called ultrafine particle size metal oxide is used in the present invention is that the transparency is not deteriorated when the metal oxide particles are dispersed in the coating film. Here, the “ultrafine particles” are generally particles on the order of submicrons, and have a particle size smaller than that of particles generally called “fine particles” having a particle size of several μm to several hundred μm. It means a small one.

The ultrafine metal oxide particles have an average particle size of 1 n.
m or more, preferably 10 nm or more, and 200
The wavelength is not more than nm, preferably 150 nm or less.
If the average particle size is less than 1 nm, it is difficult to uniformly disperse it in the high refractive index coating composition, and it becomes impossible to obtain a coating film in which the metal oxide particles are uniformly dispersed. Also, if the average particle size exceeds 200 nm, the transparency of the coating film is impaired, which is not preferable. The average particle diameter of the ultrafine metal oxide particles is determined by scanning electron microscope (SEM).
It may be visually measured from an image photograph of secondary electron emission obtained by, for example, or it may be mechanically measured by a particle size distribution meter utilizing a dynamic light scattering method or a static light scattering method.

As long as the average particle diameter of the ultrafine metal oxide particles is within the above range, the particle shape may be spherical or acicular, and any other shape may be used in the present invention. You can

Ultrafine metal oxide particles having a refractive index of 1.60 or more are used. By adding ultrafine metal oxide particles having a refractive index of 1.60 or more to the coating composition of the present invention, a coating film that can be used as a middle or high refractive index layer and a high refractive index hard coat layer of an antireflection film is obtained. Can be formed. Further, by adding metal oxide ultrafine particles having a refractive index of 1.80 or more to the coating composition according to the present invention, a high refractive index coating film having a refractive index of 1.80 or more can be easily obtained. Even if ultrafine metal oxide particles having a high refractive index are selected and used, simply dispersing them in a binder cannot sufficiently increase the refractive index of the coating film due to the dilution effect of the binder. . On the other hand, the coating composition according to the present invention enhances the refractive index improving effect by the metal oxide ultrafine particles because a part of the binder is replaced by the metal compound, and even when a considerably high refractive index is required in the design, It is possible to form a coating film having a high refractive index that meets the conditions.

Examples of the metal oxide ultrafine particles having a refractive index of 1.60 or more include titanium oxide, zirconium oxide,
Zinc oxide, cerium oxide, tin-doped indium oxide (ITO), antimony-doped tin oxide (AT
O), ultrafine particles of a metal oxide such as tin oxide can be used. As metal oxide ultrafine particles, ITO, AT
When conductive fine particles such as O and tin oxide are used, it becomes possible to impart antistatic performance to the high refractive index coating film, and thus when it is desired to prevent dust or the like from adhering to the antireflection film, or It can be used particularly preferably when it is desired to prevent liquid crystal driving failure caused by charging on the panel.

The composite (b) obtained by crosslinking the molecules of the binder component (b1) having a hydrogen bond-forming group through the metal compound (b2) forms a coating film using the coating composition of the present invention. After being dried, solidified, and optionally cured by heating or light irradiation, it is a component that becomes a binder of the coating film.

The binder component (b1) constituting the composite (b) is for imparting film-forming property or adhesion to a substrate or a low refractive index layer to the high refractive index coating composition according to the present invention. Is a component of. As the binder component, those having a hydrogen bond-forming group and a functional group capable of forming a crosslink with a metal compound, or having a hydrogen bond-forming group capable of forming a crosslink with a metal compound To use.

When the molecule of the binder component has a hydrogen bond-forming group such as a hydroxyl group, a carboxyl group, or an amide group, the dispersion stability of the ultrafine metal oxide particles is improved and can be uniformly dispersed. Water is adsorbed on the surface of the ultrafine metal oxide particles to form a hydroxyl group, and this hydroxyl group forms a hydrogen bond with the hydrogen bond forming group of the binder component, which improves the wettability of the ultrafine metal oxide particle with the binder component. It is estimated that the dispersion stability of the metal oxide ultrafine particles is improved.

The hydrogen bond-forming group of the binder component can also form a hydrogen bond with the metal compound (b2), which also contributes to the uniform distribution of the metal compound.

Further, when the binder component has a hydrogen bond-forming group, in addition to improving the dispersion stability of the metal oxide ultrafine particles, a hydrogen bond causes a hard coat layer, a low refractive index layer, and a transparent electrode layer. It is possible to improve the adhesion to the adjacent layer such as.

For example, when a medium to high refractive index layer is formed using a coating composition containing a binder component having a hydrogen bond-forming group, a hard coat layer formed from a coating solution by a so-called wet method or a low-coating layer is formed. Excellent adhesion can be obtained for both the refractive index layer and the low refractive index layer formed by a so-called dry method such as vapor deposition.

As the low refractive index layer, a silicon oxide (SiOx) film may be formed by a vapor deposition method which is a dry method or a sol-gel reaction which is a wet method. Although the silicon oxide film contains a silanol group and can form a hydrogen bond,
For such a film containing a hydrogen bond forming group, the binder component having a hydrogen bond forming group is particularly effective in improving the adhesiveness.

Conventionally, a medium-sized film formed by the wet method is used.
When forming a silicon oxide film on the high refractive index layer by vapor deposition, sufficient adhesion was not obtained, and the silicon oxide vapor deposition film was easy to peel off, while a binder component having a hydrogen bond forming group was used. Medium with the blended coating composition
When forming a high refractive index layer, a silicon oxide (SiOx) vapor-deposited film can be formed on the medium to high refractive index layer with good adhesion, which is very useful.

Further, for the purpose of antistatic, I was added to the antireflection film.
In some cases, a transparent conductive layer such as a TO vapor deposition film or an ATO vapor deposition film is provided, and a hard coat layer is formed on the transparent conductive layer. Even in such a case, by using a coating composition containing a binder component having a hydrogen bond-forming group, a high refractive index hard coat layer can be formed with good adhesion, which is very useful.

The hydrogen bond-forming group of the binder component may be a polar group having no chemical reactivity, but it reacts with a metal compound described below to form a metal compound or a condensate thereof between the binder molecule and the binder molecule. It is preferably a functional group capable of forming a crosslinked structure via. That is, the metal compound, which is one of the essential components, may be crosslinked to a functional group other than the hydrogen bond-forming group of the binder component, but a hydrogen bond-forming group that forms a hydrogen bond with the ultrafine metal oxide particles, and a metal When the cross-linking group that forms a cross-link with the compound has the same functional group, the molecular structure of the binder component is simple, so that it is easy to obtain and handle.

As long as the binder component has a hydrogen bond-forming group, it may be a reaction-curable compound such as a monomer, an oligomer or a polymer capable of undergoing a polymerization reaction, or a polymer which is not already reaction-curable. Good, from the viewpoint of imparting excellent coatability to the high refractive index coating composition according to the present invention, using a reaction curable monomer or oligomer as a binder component, by a suitable method such as photopolymerization after coating. It is preferable to polymerize it to form a binder.

Examples of the monomer that can be used as the binder component include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and carboxypolycaprolactone. Monofunctional (meth) acrylates such as acrylate, acrylic acid, methacrylic acid and acrylamide; diacrylates such as pentaerythritol triacrylate, ethylene glycol diacrylate, pentaerythritol diacrylate monostearate; trimethylolpropane triacrylate, pentaerythritol triacrylate Such as tri (meth) acrylate, pentaerythritol tetraacrylate derivative and dipentaerythritol Polyfunctional (meth) acrylates such Lumpur pentaacrylate are preferred. Specific examples of the oligomer or polymer used as the binder component include a phenol resin, a urea resin, a diallyl phthalate resin, a melamine resin, a guanamine resin, in addition to a polymer of one or more kinds of monomers exemplified above.
Examples thereof include unsaturated polyester resin, polyamide resin, polyimide resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea co-condensation resin, silicon resin and polysiloxane resin.

The reaction-curable compound as the binder component is a compound having two or more polymerizable groups such as ethylenic double bonds in one molecule, that is, a bifunctional or more polyfunctional polymerizable compound, from the viewpoint of coating strength. Is preferably used. Two
A polyfunctional polymerizable compound having a functionality or higher, and in particular, by using a monomer or an oligomer among them, in addition to the fact that the molecules of the binder component are crosslinked through the metal compound or a condensate thereof, the molecules of the binder component are Since the cross-linking bond is directly formed, the coating film strength is improved.

The metal compound (b) forming the composite (b) together with the binder component (b1) having a hydrogen bond forming group.
2) is a component which is replaced with a part of the binder component for the purpose of reducing the adverse effect that the concentration of the metal oxide fine particles in the coating composition is diluted by mixing with the binder component, and the high refractive index coating composition of the present invention. It has an effect of increasing the refractive index of the coating film formed by using the material or adjusting it to a desired value of the refractive index, and at the same time, not decreasing or improving the strength of the coating film.

The metal compound (b2) used in the present invention will be described in detail below. The above-mentioned metal oxide ultrafine particles are the main components for increasing the refractive index of the coating composition and the coating film in the present invention, and the larger the mixing ratio of the metal oxide ultrafine particles in the coating composition, the higher the refractive index. However, the refractive index of the metal oxide ultrafine particles itself approaches, but if the mixing ratio of the metal oxide ultrafine particles is too large, the amount of the binder component becomes insufficient, resulting in a decrease in coating film strength and a decrease in adhesion. I will leave.
Therefore, the amount of ultrafine metal oxide particles to be blended cannot be increased beyond a certain level.

In order to solve such a problem, the high refractive index coating composition of the present invention comprises a metal compound capable of forming a crosslink between the molecules of the binder component as an auxiliary component for increasing and adjusting the refractive index. To use. The metal compound, in the form of a single molecule or in the state of a polycondensate, condenses with two or more binder components or with two or more binder molecules produced by polymerization of the binder components,
Crosslinks are formed between the molecules of the binder. A metal compound is a reaction product (crosslinked structure, polycondensed structure) having a large refractive index and a high transparency by eliminating an organic group in such a crosslinking reaction and a polycondensation reaction to increase the content ratio of an inorganic component. Change to. Therefore, the high refractive index coating composition according to the present invention can form a coating film having a high refractive index as compared with the case where the metal compound is not used. At the same time, the metal compound or its polycondensate crosslinks between the molecules of the binder component or between the molecules of the binder produced by the polymerization of the binder component, and thus does not cause a decrease in the coating strength, rather the coating strength or The coating film hardness may be improved in some cases. Therefore, the high refractive index coating composition according to the present invention can form a coating film having coating strength and coating hardness equal to or higher than that in the case where the metal compound is not used.

It is preferable that the metal compound is capable of forming a cross-linking bond between the molecules of the binder component and capable of polycondensation between the metal compounds because the coating film strength is improved. Further, it is preferable that a part of the metal compound forming the composite is already hydrolyzed or polycondensed with the metal compound when it is present in the coating composition before coating. When a metal compound is cross-linked with the binder component and a complex that is partially hydrolyzed or partially polycondensed with the metal compound is added to the coating composition, the reactivity of the coating composition is high. Therefore, the polycondensation reaction after forming a coating film can be carried out in a short time with a small amount of energy, and the productivity of the coating film can be improved.

It is preferable to select and use as the metal compound a compound capable of forming a crosslink with the hydrogen bond forming group of the binder component, because it is not necessary to use a binder component having a complicated molecular structure. Further, when the crosslink-forming group of the metal compound is capable of forming a crosslink with the hydrogen-bond forming group of the binder component and is also a functional group capable of polycondensing the metal compounds, the metal compound Since the molecular structure of the compound is relatively simple, it is easy to obtain and handle, which is preferable.

For example, as the binder component, a binder component having a hydroxyl group as a hydrogen bond forming group such as a polyfunctional (meth) acrylate monomer having a hydroxyl group is used, and as the metal compound, two or more alkoxyl groups directly bonded to a metal atom are used. The combination using the alkoxide or the chelate thereof can be exemplified. In this combination, the alkoxyl group of the alkoxide is dealcoholized and polycondensed with the hydroxyl group of the binder component to form a crosslinking bond to form a complex, and the alkoxyl groups are also dehydrated and polycondensed to directly polycondense the alkoxides. Structures can be formed in the complex. Further, the alkoxide having two or more alkoxyl groups also has the function of selectively adsorbing to the metal oxide ultrafine particles to improve the dispersibility and stability of the ultrafine particles.

The metal compounds usable in the present invention include:
A compound represented by the following formula (1) or a chelated product thereof can be used. Formula (1): AnMBx-n (In Formula (1), M is a metal atom, A is a hydrolyzable functional group or a hydrocarbon group having a hydrolyzable functional group, B
Represents an atomic group covalently or ionically bonded to the metal atom M. x represents the valence of the metal atom M, and n represents an integer of 2 or more and x or less. ) Examples of the hydrolyzable functional group A include an alkoxyl group, a halogen such as a chlorine atom, an ester group, and an amide group. The metal compound belonging to the above formula (1) includes an alkoxide having two or more alkoxy groups directly bonded to a metal atom, or a chelate thereof. Preferred metal compounds include a titanium alkoxide, a zirconium alkoxide, a silicon alkoxide, a silane coupling agent, from the viewpoint of refractive index and reinforcing effect of coating film strength, ease of handling, material cost, and the like.
Alternatively, chelate products thereof can be exemplified. Note that titanium alkoxide and zirconium alkoxide are also raw material compounds of titanium oxide and zirconium oxide, which are preferable ultrafine particles of metal oxide. When an alkoxide corresponding to the raw material of the metal oxide ultrafine particles to be used or a chelate thereof is available, the alkoxide corresponding to the metal oxide ultrafine particles or a chelate thereof is usually used as the auxiliary metal compound. use.

Titanium alkoxide is a compound represented by the following formula (2). Formula (2): Ti (OR) ₄ (R in the formula (2) is an alkyl group, preferably 1 to 1 carbon atoms.
Represents 10 alkyl groups. ) Specifically, tetramethoxy titanium, tetraethoxy titanium, tetra-iso-propoxy titanium, tetra-n
-Propoxy titanium, tetra-n-butoxy titanium, tetra-sec-butoxy titanium, tetra-tert-butoxy titanium and the like can be mentioned.

Zirconium alkoxide is a compound represented by the following formula (3). Formula (3): Zr (OR) ₄ (R in the formula (3) is an alkyl group, preferably 1 to 1 carbon atoms.
Represents 10 alkyl groups. ) Specifically, tetramethoxyzirconium, tetraethoxyzirconium, tetra-iso-propoxyzirconium, tetra-n-propoxyzirconium, tetra-n-butoxyzirconium, tetra-sec-butoxyzirconium, tetra-tert-butoxyzirconium, etc. Can be mentioned.

The silicon alkoxide and the silane coupling agent are compounds represented by the following formula (4). Formula (4): RmSi (OR ') n (R in Formula (4) is an alkyl group (preferably having a carbon number of 1 to 1).
10 alkyl group) or a reactive group such as a vinyl group, a (meth) acryloyl group, an epoxy group, an amide group, a sulfonyl group, a hydroxyl group, a carboxyl group or an alkoxyl group, and R ′ is an alkyl group (preferably a carbon group). The alkyl group of the numbers 1 to 10), and m + n is an integer of 4. ) Specifically, tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n
-Propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, tetrapentaethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-
Propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldi Ethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, dimethylbutoxysilane, methyldimethoxysilane, methyldiethoxysilane, hexyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glyce Sidoxypropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) trimethoxysilane and the like can be mentioned.

Preferred chelating agents for forming a chelate by coordinating with a free metal compound include alkanolamines such as diethanolamine and triethanolamine; glycols such as ethylene glycol, diethylene glycol and propylene glycol; acetylacetone. Examples thereof include ethyl acetoacetate and the like having a molecular weight of 10,000 or less. By using these chelating agents, it is possible to form a chelated product which is stable against the inclusion of water and has an excellent reinforcing effect on the coating film.

The above chelating agent is preferably used in a proportion of 0.1 to 2 mol per 1 mol of metal atom of the free metal compound for coordinating the chelating agent. If the ratio of the chelating agent is less than 0.1 mol, the stabilizing effect is insufficient. On the other hand, if the ratio of the chelating agent exceeds 2 mols, the chelating agent that has not been consumed for the formation of the chelated product is present in the solution as an impurity of the organic substance, so that the strength and the transparency of the coating film are likely to decrease.

In the present invention, the binder component (b1) having a hydrogen bond-forming group and the metal compound (b2) capable of forming a crosslink between the molecules of the binder component.
Is present in the coating composition in the form of a composite in which the two are crosslinked, rather than in separate form. The reason why the binder component (b1) and the metal compound (b2) are used in the form of a composite will be described in detail below.

When the binder component having a hydrogen bond-forming group and the metal compound capable of being crosslinked with the binder component are present in the coating composition in separate forms which are not a composite, the coating composition When the binder component and the metal compound are crosslinked in the product or the coating film thereof, the distribution of the metal compound may not be sufficiently uniform. In particular, when a metal compound capable of being hydrolyzed and polycondensed is blended in the coating composition and the metal compound in the coating composition or the coating film is hydrolyzed, crosslinking between the binder component and the metal compound is performed. Since the polycondensation reaction between the metal compounds proceeds more predominantly than the bonding, the polycondensate of the metal compound pushes away the binder component and easily aggregates, resulting in a decrease in optical uniformity and film strength.

On the other hand, in the present invention, the binder component and the metal compound are present in the coating composition in the form of a complex in which the molecules of the binder component are cross-linked through the metal compound. Fix the metal compound in the binder component in a uniformly distributed state,
Since it is possible to prevent the aggregation of the metal compound or its polycondensate,
It is possible to sufficiently improve the uniformity of the coating composition and the optical uniformity and the film strength of the coating film formed using the coating composition.

A method for forming a complex by using a binder component (b1) having a hydrogen bond-forming group and a metal compound (b2) capable of forming a crosslink bond between molecules of the binder component is a method of forming a crosslink bond. There are various types of reaction that can be performed. In particular, when a metal compound having polycondensation reactivity is used, the crosslinking reaction between the binder component and the metal compound is carried out so that the distribution of the metal compound or its polycondensate becomes uniform. It must proceed predominantly over the reaction.

For example, the combination of using a binder component having a hydroxyl group as a hydrogen bond-forming group and an alkoxide having two or more alkoxyl groups directly bonded to a metal atom or a chelate thereof is a binder having an alkoxyl group of an alkoxide as described above. Since it is possible to form a structure in which the alkoxyl groups are dehydrated and polycondensed with each other to form a direct polycondensation of the alkoxides with each other, it is preferable to form a complex by dealcohol polycondensation with the hydroxyl group of the component to form a cross-linking bond. It is a combination. However, in this combination, dealcohol polycondensation that causes cross-linking between the alkoxide and the binder component and dehydration polycondensation that occurs between the molecules of the alkoxide become competitive reactions. In this case, in order to predominantly promote the cross-linking of the alkoxide and the binder component to prevent aggregation of the polycondensate of the alkoxides with each other, and to add a hydroxyl group to the hydrogen of the metal oxide ultrafine particles to the binder component molecule. In order to leave it, the amount of the alkoxide (b2) used with respect to the binder component (b1) is limited to 1 or less at the reaction equivalent ratio (b2 / b1) to carry out the crosslinking reaction.

For the production of the complex, for example, a transesterification reaction is carried out in a system free from water while the alcohol produced by heating is distilled off. The reaction temperature is usually 70 ° C or higher,
Preferably, the temperature is 80 ° C. or higher, and usually 150 ° C. or lower,
The temperature is preferably 130 ° C. or lower, and usually 20 hours or less, preferably 15 hours or less with continuous stirring. Further, since the dehydration polycondensation reaction between metal compounds is promoted by hydrolysis, it is preferable to substantially eliminate water from the crosslinking reaction system.

By controlling the reaction equivalents to carry out the reaction in this way, the crosslinking reaction between the binder component and the alkoxide is selectively advanced, and the alkoxides are not polycondensed at all or only partially polycondensed. It becomes possible to stop, and a complex in which the molecules of the binder component are cross-linked through the alkoxide or its partial polycondensate is obtained.

The cross-linking reaction between the binder component and the metal compound may be carried out in the coexistence of other components of the coating composition, for example, ultrafine metal oxide particles and other components which are optionally incorporated. In addition, when the amount of the metal compound to be cross-linked with the binder component is limited to an amount smaller than the amount of the metal compound to be finally blended in the coating composition, the insufficient amount of the metal compound causes the cross-linking reaction to occur. It may be additionally compounded in the finished composite or in the coating composition.

In addition to the above-mentioned essential components, other components may be added to the high refractive index coating composition of the present invention, if necessary. As the desired component, for example, a photopolymerization initiator is used when it is desired to photopolymerize the binder component, and a dispersant is used when it is desired to improve the dispersibility of the metal oxide ultrafine particles.

As the photopolymerization initiator, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4-
(Methylthio) phenyl) -2-morpholinopropan-1-one, 2- (dimethylamino) -1- (4- (morpholinyl) phenyl) -2-phenylrotyl) -1
-Butanone and the like are preferred.

Further, when a heating means is used for the curing treatment, a thermal polymerization initiator such as benzoyl peroxide is added by heating to generate radicals to initiate the polymerization of the polymerizable compound. Is also good.

The dispersant is appropriately selected and used depending on the surface condition of the metal oxide ultrafine particles to be used and the solvent used for dispersion. Since such polar groups are present, it is preferable to use a dispersant having an ethylene oxide chain and having an anionic group such as a phosphoric acid group, a sulfonic acid group, an amino group, or an ammonium group at the molecular chain and terminal. preferable. Such a dispersant is preferably used because it is selectively adsorbed on the surface of the ultrafine metal oxide particles, improves the affinity with the binder component, and at the same time prevents reaggregation of the ultrafine particles.

The solvent that dissolves or disperses each of the above essential components and other components that are used as necessary is not particularly limited, but examples thereof include alcohols such as isopropyl alcohol, methanol and ethanol; methyl ethyl ketone, methyl isobutyl ketone, and the like. Ketones; Esters such as ethyl acetate and butyl acetate; Halogenated hydrocarbons;
Aromatic hydrocarbons such as toluene and xylene; or mixtures thereof can be used.

The mixing ratio of each component can be adjusted appropriately, but preferably, the metal oxide ultrafine particles are added as an essential component to 10 parts by weight based on the total weight of the mixing components excluding the solvent.
It is preferable that the content of the dispersant and other components is contained in an amount of ˜95% by weight, and 5 to 90% by weight of the composite, and the total amount is less than the total amount. If the blending ratio of any of the essential components is out of this range, either the coating strength or the refractive index is often insufficient.

When a dispersant is further added to the high refractive index coating composition of the present invention, an effective amount of 30% by weight or less based on the amount of ultrafine metal oxide particles is added. In the present invention, since the binder component has a hydrogen bond-forming group, the dispersion stability of the metal oxide ultrafine particles can be considerably improved even by adding a small amount of a dispersant.

The amount of solvent is such that each component is uniformly dissolved,
The concentration is adjusted so that it can be dispersed, does not cause aggregation during storage after preparation, and is not too dilute at the time of coating. Within the range where this condition is satisfied, reduce the amount of solvent used to prepare a high-concentration coating composition, store it in a state that does not take up the volume, and take out the necessary amount at the time of use to obtain a concentration suitable for coating work. It is preferably diluted.

In order to prepare the high refractive index coating composition according to the present invention using the above components, the dispersion treatment may be carried out according to a general method for preparing a coating liquid. For example, ultrafine metal oxide particles, a composite of a binder component and a metal compound, an additional amount of the metal compound, a solvent, and other desired components are mixed in any order, and a medium such as beads is added to the obtained mixture. Then, a high-refractive-index coating composition can be obtained by performing an appropriate dispersion treatment with a paint shaker, a bead mill, or the like.

Further, ultrafine metal oxide particles, a binder component, a metal compound, a solvent, and other desired components are mixed in an arbitrary order to prepare a mixture, and the binder component and the metal compound in this mixture are selected. The coating composition of the present invention can also be prepared by subjecting the composite to a cross-linking reaction to form a composite, and then additionally blending the deficiency of the metal compound.

In the case where the metal compound has hydrolysis / polycondensation properties, after the coating composition of the present invention is prepared, the metal compound present in the composition in a free or complex state is removed. Further, partial hydrolysis and / or partial polycondensation is preferable because hydrolysis and polycondensation after coating can be carried out in a short time and with low energy. At this stage, the cross-linking bond between the binder component and the metal compound has already been sufficiently formed, and the metal compound or the partial polycondensate thereof is uniformly distributed among the molecules of the binder component to form a complex. Therefore, even if the metal compound is additionally partially hydrolyzed and polycondensed, the uniformity of the coating composition and the coating film is not easily impaired.

Metal compounds such as titanium alkoxides,
When the zirconium alkoxide, silicon alkoxide, silane coupling agent, or chelate thereof is partially hydrolyzed, it is preferable to add water in an amount of 2 mol or less per 1 mol of the metal compound. Addition of water in excess of 2 mole times to these metal compounds is not preferable because the hydrolysis proceeds excessively and the stability of the coating composition and the adhesion of the resulting coating film are extremely reduced.

This partial hydrolysis is usually carried out at a temperature of 5 ° C. or higher, preferably 10 ° C. or higher, and usually 50 ° C. or lower, preferably 30 ° C. or lower, usually for 5 minutes or longer, preferably for 30 minutes.
It is carried out for a minute or more and usually 3 hours or less, preferably 1 hour or less with continuous stirring.

A dilute acid catalyst can be used for the partial hydrolysis. Preferred acid catalysts include, for example, hydrochloric acid,
Acids such as nitric acid, sulfuric acid, or acetic acid can be used.
These acids are usually added in an amount of 0.001 N or more, preferably 0.
An acid catalyst aqueous solution is obtained by preparing an aqueous solution of 005 N or more and usually 20.0 N or less, preferably 1 N or less and adding it to the metal compound before mixing with other components or the mixture of the metal compound and other components. Is used for hydrolysis. Depending on the conditions, it may not be necessary to add more water.

The high-refractive-index coating composition thus obtained is a composite in which the molecules of the metal oxide ultrafine particles and the binder component having a hydrogen bond-forming group are cross-linked through a metal compound or a partial polycondensate thereof. And, if necessary, other components such as a dispersant are dissolved or dispersed in a solvent. In the coating composition, a part or all of the metal oxide fine particles are hydrogen-bonded through the hydrogen bond-forming groups remaining in the binder component constituting the composite and uniformly dispersed.

The high refractive index coating composition according to the present invention is a milky white liquid, can maintain a stable solution state for several months, has a long pot life, and has good wettability to a substrate. It has excellent coating suitability.

In order to form a coating film having sufficient coating strength using the high refractive index coating composition of the present invention,
It is desirable to meet the following conditions. That is,
0.2 g of coating amount of the high refractive index coating composition of the present invention
/ M ² and heated at 120 ° C. for 2 minutes, and then extracted with a good solvent for the binder component, the weight ratio of the solid content remaining after extraction to the solid content before extraction,
That is, it is desirable that the gel fraction be 10% or more.
Here, the "good solvent for the binder component" is a solvent capable of uniformly dissolving the binder component in the concentration range usable in the present invention. When the gel fraction measured under the above test conditions is 10% or more, it can be said that a sufficient amount of crosslinking bonds are formed between the molecules of the binder component via the metal compound or its polycondensate. Therefore, insufficient coating strength does not occur due to insufficient binder components.

The high refractive index coating composition of the present invention is applied to the surface of an article to be coated such as a substrate, dried, and optionally polycondensed and cured to give a substantially colorless and transparent high refractive index composition. A rate coating film can be formed.

The substrate to which the high refractive index coating composition of the present invention is applied is not particularly limited. Preferred base materials include, for example, glass plates; triacetate cellulose (TAC), polyethylene terephthalate (PET),
Diacetyl cellulose, acetate butyrate cellulose, polyether sulfone, acrylic resin; polyurethane resin; polyester; polycarbonate; polysulfone; polyether; trimethylpentene; polyetherketone; films formed of various resins such as (meth) acrylonitrile Can be illustrated. The thickness is usually about 25 μm to 1000 μm.

High refractive index coating compositions include, for example:
It can be applied on the substrate by various methods such as spin coating, dipping, spraying, slide coating, bar coating, roll coater, meniscus coater, flexo printing, screen printing and bead coater. it can.

The high-refractive-index coating composition of the present invention is applied on the surface of an article to be coated such as a substrate in a desired coating amount, and then usually dried by heating with a heating means such as an oven. When the metal compound forming the complex can be hydrolyzed and polycondensed, the hydrolysis and condensation reaction is allowed to proceed while removing the solvent in this heating and drying step. The hydrolysis-condensation reaction between metal compounds is usually carried out under the condition of heating at 30 ° C. or higher for 1 hour or longer. When a polymer that has been polymerized from the beginning is used as the binder component, a coating film having a high refractive index can be obtained when this hydrolysis condensation reaction is completed.

When a reaction-curable compound is used as the binder component, the coating film of the high refractive index coating composition is usually heated and dried and then irradiated with ultraviolet rays (UV) or ionizing radiation (EB). By photopolymerization or other suitable polymerization method to polymerize the binder component to produce a polymeric binder, and then heat for a certain period of time to promote the hydrolysis-condensation reaction to remove the metal compound in the complex. Polycondensate. When a photopolymerizable binder component such as an ethylenic double bond-containing monomer is used, usually, after the coating film is dried by heating, the binder component is photocured by irradiation with ionizing radiation (EB),
Then, the hydrolysis condensation reaction is performed by heating at 30 ° C. or higher for 1 hour or longer. When the binder component is a polyfunctional reaction-curable compound, a cross-linking bond that directly bonds between the binder molecules is also formed by the polymerization reaction of the binder components, and the coating film strength is improved. When a reaction-curable compound is used as the binder component, a high-refractive index coating film can be obtained by completing the above-mentioned hydrolysis condensation reaction and polymerization reaction of the binder component.

Thus, the high refractive index coating film according to the present invention is obtained. The high refractive index coating film is a metal oxide having an average particle diameter of 1 to 200 nm and a refractive index of 1.60 or more in a binder obtained by crosslinking a polymer having a hydrogen bond forming group with a metal compound or a polycondensate thereof. Although it is formed by dispersing ultrafine particles, it may contain other components as necessary. Examples of the other component include components such as a dispersant which is optionally blended with the coating composition.

In the high-refractive index coating film according to the present invention, the metal oxide ultrafine particles are uniformly dispersed in a state in which all or part of them are hydrogen-bonded to the hydrogen-bond forming group of the binder.

The binder is composed of a polymer portion having a hydrogen bond-forming group and a metal compound or polycondensation portion thereof which crosslinks the molecules of the polymer.
The molecules of the polymer having a hydrogen bond-forming group may be cross-linked with each other via the molecular structure of the metal compound or its polycondensate and may be further directly cross-linked.
It is preferable that such a direct cross-linking bond is present between the molecules of the polymer having a hydrogen bond-forming group, because the coating film strength is excellent. As described above, when a polyfunctional reaction-curable compound having a hydrogen bond-forming group is used as the binder component, a cross-linking bond that directly bonds the molecules of the polymer having the hydrogen bond-forming group is formed.

The metal compound has two or more of the same functional groups, the functional groups can be cross-linked with the hydrogen bond-forming group present in the polymer portion constituting the binder, and the functional groups are also heavy. In some cases condensation is possible. In such a case, as described above, a part of the functional group reacts with a part of the hydrogen bond-forming group of the polymer to form a cross-link bond through a metal compound or a polycondensate thereof, The other part reacts with the functional groups to form a polycondensed part of the metal compound in an amorphous form.

For example, when an alkoxide having two or more alkoxyl groups directly bonded to a metal atom or a chelate thereof is used as the metal compound, a part of the alkoxyl group of the metal compound is a hydrogen bond forming group of the polymer. It is possible to obtain a high refractive index coating film having a structure in which a part of them is condensed to form a cross-linking bond and the other part is hydrolyzed and condensed between the alkoxyl groups to polycondense the alkoxide. Examples of the alkoxide having two or more alkoxy groups directly bonded to a metal atom or a chelate thereof include titanium alkoxide, zirconium alkoxide, silicon alkoxide, silane coupling agent, any chelate thereof, or a mixture thereof. You can

The high-refractive-index coating film according to the present invention has good adhesion to a substrate, a low-refractive-index layer, etc., is excellent in coating strength, has a high refractive index, is substantially transparent, and is antireflection. It can be suitably used as a layer constituting the film, particularly as a high refractive index layer.

The high refractive index coating film according to the present invention can have a refractive index of 1.65 or more, and can be combined with one or more layers having different refractive indexes to form an antireflection film. Even when a particularly high refractive index is required in relation to the low refractive index layer, the high refractive index coating film according to the present invention can adjust the refractive index to a high value of 1.80 or more. Then, the refractive index of the high refractive index layer according to the present invention is 1. by appropriately selecting and adjusting the type and blending amount of the metal oxide ultrafine particles as well as the type and blending amount of the metal compound that crosslinks the binder component. It can be easily adjusted to a high value of 65 or more or 1.80 or more, and a specific value (predetermined value) set in advance in relation to the refractive index of another layer such as the low refractive index layer.

Further, for the high refractive index coating film according to the present invention,
When a material having a lower refractive index than that is applied or laminated by a film forming method such as vacuum film formation such as vapor deposition to form an adjacent layer such as a low refractive index layer, a high refractive index according to the present invention The coating film exhibits good adhesion to the adjacent layer formed by any method. The high-refractive-index coating film according to the present invention exhibits good adhesion to an adjacent layer such as a coating film or a vapor deposition film by the action of a hydrogen bond-forming group of a binder component, and an inorganic bond composed of an inorganic metal. Conceivable. The adhesiveness of the high refractive index coating film according to the present invention is 1 in 100 cross-cuts when the cross-cut cellophane tape peeling test of 10 × 10 specified in JIS K 5600-5-6 is performed. It can be less than or equal to an individual.

The coating hardness of the high refractive index coating film according to the present invention is such that the coating composition according to the present invention is applied directly or through another layer to a final film thickness of 0.1 μm. After curing, the pencil hardness test based on JIS K 5600-5-4 can be set to H or higher when measured with a load of 1 kg.

Further, in the high refractive index coating film according to the present invention, the tensile strength of the coating film can be significantly improved by forming a cross-linking bond in the state where the metal compound is uniformly distributed between the binder components. it can. Specifically, using the coating composition according to the present invention as a test sample, the JIS
A test piece was prepared based on K7113, and a tensile test was performed to measure the breaking strength, and a coating composition having a composition obtained by removing a metal compound from the coating composition of the test sample was used as a comparative sample.
It is possible to improve the strength by 1.3 times or more as compared with the breaking strength measured by preparing a test piece based on SK7113 and performing a tensile test.

Further, the colorless transparency of the high refractive index coating film according to the present invention is 500 to 800 nm when measured with a spectrophotometer.
The transmittance in the range can be 90% or more.

The high refractive index coating film according to the present invention can be suitably used for forming an antireflection film. The high-refractive-index coating film according to the present invention forms one layer of a multi-layered antireflection film formed by laminating two or more layers having a light-transmitting property and different refractive indexes (light-transmitting layers). Can be used for. The high refractive index coating film according to the present invention can be used mainly as a high refractive index layer or a medium refractive index layer. The high refractive index coating film according to the present invention can also be used as a hard coat layer capable of functioning as a medium to high refractive index, that is, a high refractive index hard coat layer. In the multilayer antireflection film, the layer having the highest refractive index 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 a layer having an intermediate refractive index other than that is It is called a medium refractive index layer.

Further, even if only one layer of the high refractive index coating film according to 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 present invention can be improved. An antireflection effect can be obtained when the refractive index of the high refractive index coating film is just well balanced. Therefore, the high refractive index coating film according to the present invention may function effectively as a single-layer antireflection film.

The high refractive index coating film according to the present invention is particularly suitable for image display devices such as liquid crystal display devices (LCD), cathode ray tube display devices (CRT), plasma display panels (PDP), and electroluminescence displays (ELD). It is preferably used for forming at least one layer, especially a high refractive index layer, of a multi-layered antireflection film that covers the display surface.

FIG. 1 schematically shows a cross section of an example (101) of a liquid crystal display device in which a display surface is covered with a multilayer antireflection film containing a high refractive index coating film according to the present invention. The liquid crystal display device 101 includes a color filter 4 formed by forming RGB pixel portions 2 (2R, 2G, 2B) and a black matrix layer 3 on one surface of a glass substrate 1 on the display surface side.
The transparent electrode layer 5 is provided on the pixel portion 2 of the color filter, the transparent electrode layer 7 is provided on one surface of the glass substrate 6 on the backlight side, and the glass substrate on the backlight side and the color filter are transparent. The electrode layers 5 and 7 are opposed to each other with a predetermined gap therebetween, and the periphery is adhered with a sealing material 8, the liquid crystal L is sealed in the gap, and the alignment film 9 is provided on the outer surface of the glass substrate 6 on the back side. The polarizing film 10 is formed, the polarizing film 10 is attached to the outer surface of the glass substrate 1 on the display surface side, and the backlight unit 11 is arranged in the rear.

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, both surfaces of a polarizing element 12 made of polyvinyl alcohol (PVA) or the like are covered with protective films 13 and 14 made of triacetyl cellulose (TAC) or the like, and an adhesive layer 15 is provided on the back surface side. The hard coat layer 16 and the multilayer antireflection film 17 are sequentially formed on the viewing side, and the hard coat layer 16 and the multilayer antireflection film 17 are attached to the glass substrate 1 on the display surface side via the adhesive layer 15.

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

The multilayer antireflection film 17 has a three-layer structure in which a middle refractive index layer 18, a high refractive index layer 19 and a low refractive index layer 20 are sequentially laminated from the backlight side to the viewing side. ing. 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 an uneven shape, the multilayer antireflection film 17 formed thereon also has an uneven shape as illustrated.

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 substance such as silica or magnesium fluoride, a fluororesin or the like. You can The medium refractive index layer 18 and the high refractive index layer 19 can be formed by using the high refractive index coating film according to the present invention, and the medium refractive index layer 18 has a refractive index of 1.46 to.
1.80 in the range, the high refractive index layer 19 has a refractive index of 1.6
Five or more are used.

By the action of this antireflection film, the reflectance of the light emitted from the external light source is reduced, so that the reflection of scenery and fluorescent lamps is reduced and the visibility of the display is improved. Further, by using the hard coat layer 16 as an antiglare layer, straight traveling light and external light from the inside are scattered,
The glare of reflection is reduced, and the visibility of the display is further improved.

In the case of the liquid crystal display device 101, the high refractive index coating composition according to the present invention is applied to a laminate composed of the polarizing element 12 and the protective films 13 and 14 to adjust the refractive index to 1.46 to 1.80. It is possible to form the middle refractive index layer 18 and the high refractive index layer 19 with the refractive index adjusted to 1.65 or more, and further to provide the low refractive index layer 20. Then, the polarizing film 10 including the antireflection film 17 can be attached to the viewing-side glass substrate 1 via the adhesive layer 15.

On the other hand, since the orientation plate is not attached to the display surface of the CRT, it is necessary to directly provide the antireflection film.
However, applying the high refractive index coating composition according to the present invention to the display surface of a CRT is a complicated task.
In such a case, an antireflection film containing the high-refractive index coating film according to the present invention is produced, and the antireflection film is formed by adhering it to the display surface. It is not necessary to apply the high refractive index coating composition according to the present invention.

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 side of the light-transmitting substrate film. An antireflection film can be obtained by forming the film with the high refractive index coating film according to 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 (102) of the antireflection film containing the high refractive index coating film according to the present invention. In the antireflection film 102, the high refractive index layer 22 is formed by applying the high refractive index coating composition according to the present invention on one surface side of the base film 21 having light transmittance.
And a low refractive index layer 23 on the high refractive index layer.
Is provided. In this example, the light transmission layers having different refractive indices are only two layers, a high refractive index layer and a low refractive index layer,
You may provide three or more light transmission layers. In that case, not only the high refractive index layer but also the medium refractive index layer can be formed by applying the high refractive index coating composition according to the present invention.

[0128]

Examples (Example 1) (1) Preparation of complex 10.0 parts by weight of pentaerythritol triacrylate (PET30, manufactured by Nippon Kayaku Co., Ltd.), which is a binder component, and titanium-n-butoxide 9.14. A part was added (0.8 mol amount based on the hydroxyl group of pentaerythritol triacrylate), and a butanol reaction was performed at 110 ° C. for 1 hour to prepare a complex.

(2): Preparation of High Refractive Index Coating Composition The following components including the above complex were put in a mayonnaise bottle, and zirconia beads were used as a medium to a paint shaker.
The mixture was shaken for a time to obtain a titania ultrafine particle dispersion liquid (high refractive index coating composition).

<Composition of titania ultrafine particle dispersion> Titania ultrafine particles (average particle diameter 30 nm by scanning electron microscope observation, trade name TTO51 (C), manufactured by Ishihara Techno Co., Ltd.): 10 parts by weight dispersant (Brand name Disperbic 163, manufactured by Big Chemie Co., Ltd.): 2 parts by weight-Complex: 4 parts by weight-Photoinitiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 0.2 parts by weight-Methyl Isobutyl ketone: 135 parts by weight (Example 2) (1) Preparation of complex 10.0 parts by weight of pentaerythritol triacrylate (PET30, manufactured by Nippon Kayaku Co., Ltd.) as a binder component, and titanium-n-butoxide 5 .71 parts by weight (1 to the hydroxyl group of pentaerythritol triacrylate
(2 mol amount) was added, and a butanol removal reaction was performed at 110 ° C. for 1 hour to prepare a complex.

(2) Preparation of High Refractive Index Coating Composition The following components including the above composite were placed in a mayonnaise bottle, and zirconia beads were used as a medium to a paint shaker.
The mixture was shaken for a time to obtain a titania ultrafine particle dispersion liquid (high refractive index coating composition).

<Composition of titania ultrafine particle dispersion> Titania ultrafine particles (average particle size 30 nm by scanning electron microscope observation, trade name TTO51 (C), manufactured by Ishihara Techno Co., Ltd.): 10 parts by weight Dispersant (Brand name Disperbic 163, manufactured by Big Chemie Co., Ltd.): 2 parts by weight-Complex: 4 parts by weight-Photoinitiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 0.2 parts by weight-Methyl Isobutyl ketone: 135 parts by weight (Example 3) (1) Preparation of complex 10.0 parts by weight of pentaerythritol triacrylate (PET30, manufactured by Nippon Kayaku Co., Ltd.), which is a binder component, and zirconium-n-butoxide 6 were added. Add 0.43 parts by weight (1/2 molar amount based on the hydroxyl group of pentaerythritol triacrylate) and remove the butanone at 110 ° C for 1 hour. It was prepared a complex effect a reaction.

(2): Preparation of high-refractive index coating composition The following components including the above complex were put in a mayonnaise bottle, and zirconia beads were used as a medium to a paint shaker.
The mixture was shaken for a time to obtain a titania ultrafine particle dispersion liquid (high refractive index coating composition).

<Composition of titania ultrafine particle dispersion liquid> Titania ultrafine particles (average particle size 30 nm by scanning electron microscope observation, trade name TTO51 (C), manufactured by Ishihara Techno Co., Ltd.): 10 parts by weight dispersant (Brand name Disperbic 163, manufactured by Big Chemie Co., Ltd.): 2 parts by weight-Complex: 4 parts by weight-Photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 0.2 parts by weight- Methyl isobutyl ketone: 135 parts by weight (Comparative Example 1) Except for the fact that titanium-n-butoxide was not added in Example 1, the same procedure as in Example 1 above was carried out to obtain a titania-free metal compound capable of crosslinking the binder component. A fine particle dispersion was prepared. That is, the following components were placed in a mayonnaise bottle and shaken for 7 hours with a paint shaker using zirconia beads as a medium to obtain a titania ultrafine particle dispersion liquid (high refractive index coating composition).

<Composition of titania ultrafine particle dispersion> Titan ultrafine particles (average particle size 30 nm by scanning electron microscope observation, trade name TTO51 (C), manufactured by Ishihara Techno Co., Ltd.): 10 parts by weight dispersant (Brand name Disperbic 163, manufactured by Big Chemie Co., Ltd.): 2 parts by weight pentaerythritol triacrylate (PET3)
0, manufactured by Nippon Kayaku Co., Ltd .: 4.0 parts by weight Photoinitiator (IRGACURE 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 0.2 parts by weight Methyl isobutyl ketone: 135 parts by weight (Comparative Example) 2) A titania ultrafine particle dispersion having the same composition as in Example 1 was prepared without preliminarily preparing the composite.
That is, the following components were placed in a mayonnaise bottle and shaken for 7 hours with a paint shaker using zirconia beads as a medium to obtain a titania ultrafine particle dispersion liquid (high refractive index coating composition).

<Composition of titania ultrafine particle dispersion> Titan ultrafine particles (average particle size 30 nm by scanning electron microscope observation, trade name TTO51 (C), manufactured by Ishihara Techno Co., Ltd.): 10 parts by weight dispersant (Brand name Disperbic 163, manufactured by Big Chemie Co., Ltd.): 2 parts by weight pentaerythritol triacrylate (PET3)
0, manufactured by Nippon Kayaku Co., Ltd .: 2.1 parts by weight Titanium-n-butoxide: 1.9 parts by weight (0.8 with respect to the hydroxyl group of pentaerythritol triacrylate).
Molar amount) -Photoinitiator (IRGACURE 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 0.2 parts by weight-Methyl isobutyl ketone: 135 parts by weight (Example 4: Preparation of three-layer antireflection film) (4- a) Preparation of transparent hard coat film (1) Prepare a PET substrate (A-4350, manufactured by Toyobo Co., Ltd.) having a thickness of 188 μm, one surface of which is subjected to the treatment for improving the adhesiveness, and apply the following composition to the surface of the easily adhesive treatment. Hard coating solution (1) is applied with a bar coater, the solvent is dried, and then UV irradiation device (Fusion UV Systems Japan Co., Ltd.)
(Manufactured by Hamamatsu Co., Ltd.) was used as a light source to cure the H valve at a dose of 500 mJ to form a transparent hard coat film having a thickness of 10 μm to obtain a hard coat substrate (1).

<Composition of hard coat coating liquid (1)> Dipentaerythritol pentaacrylate: 7 parts by weight Colloidal silica dispersion (solid content 25% by weight, MEK
-ST, Nissan Chemical Co., Ltd .: 12 parts by weight Photoinitiator (Irgacure 184, Ciba Specialty Chemicals Co., Ltd.): 0.3 parts by weight Methyl isobutyl ketone: 20 parts by weight (4-b) ) Preparation of transparent hard coat film (2) A hard coat coating solution (2) having the following composition is coated on a triacetyl cellulose substrate with a bar coater, the solvent is dried, and then a UV irradiation device (Fusion UV Systems) is used. 300m using H bulb of Japan Co., Ltd. as a light source
It was cured at an irradiation dose of J to form a transparent hard coat film having a thickness of 4 μm to obtain a hard coat substrate (2).

<Composition of hard coat coating liquid (2)> Pentaerythritol tetraacrylate: 20 parts by weight Photopolymerization initiator (IRGACURE 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 1 part by weight Methyl isobutyl ketone : 80 parts by weight (4-c) Preparation of antiglare-imparting hard coat film (3) A hard coat coating solution (3) having the following composition was coated on a triacetyl cellulose substrate with a bar coater to prepare a solvent. After drying, the H bulb of a UV irradiation device (Fusion UV Systems Japan KK) was used as a light source for 300 m.
The coating was cured at an irradiation dose of J to form a hard coat film having an antiglare property with a thickness of 4 μm to obtain a hard coat base material (3).

<Composition of Hard Coat Coating Liquid (3)> Pentaerythritol tetraacrylate: 30.0
Parts by weight-Cellulose acetate propionate: 0.4 parts by weight-Polystyrene bead paste (SX-130, manufactured by Soken Chemical Co., Ltd.): 10.0 parts by weight-Photopolymerization initiator (Irgacure 184, Ciba Specialty Chemicals ( Co., Ltd.): 2.7 parts by weight Methylisobutylketone: 72.0 parts by weight (4-d) Formation of medium refractive index layer The titania ultrafine particle dispersion obtained in Example 3 was used as a hard coat substrate ( Each of 1), (2) and (3) is coated with a bar coater on the hard coat film side, dried with a solvent, and then U
An H bulb of a V irradiation device (manufactured by Fusion UV Systems Japan Co., Ltd.) was used as a light source to cure at an irradiation amount of 300 mJ, and then heated at 40 ° C. for 6 hours in an oven to obtain a medium refractive index layer. The thickness of the medium refractive index layer is 550 when the reflectance is measured with a spectrophotometer (manufactured by Shimadzu Corporation).
It was set so that the minimum reflectance would be around nm.

(4-e) Formation of High Refractive Index Layer The titania ultrafine particle dispersion obtained in Example 1 was coated on the medium refractive index layer formed in the above step with a bar coater,
After drying the solvent, the H bulb of a UV irradiation device (Fusion UV Systems Japan Co., Ltd.) was used as a light source for 30 minutes.
After curing with a dose of 0 mJ, in an oven at 40 ° C for 6
It heated for time and formed the high refractive index layer. The film thickness of the high refractive index layer was set so that the minimum reflectance was around 550 nm when the reflectance was measured with a spectrophotometer (manufactured by Shimadzu Corporation).

(4-f) Formation of Low Refractive Index Layer A coating liquid for low refractive index having the following composition was applied on the high refractive index layer formed in the above step with a bar coater, and after drying the solvent,
An H bulb of a UV irradiation device (manufactured by Fusion UV Systems Japan Co., Ltd.) was used as a light source and cured at an irradiation dose of 300 mJ to form a low refractive index layer. The film thickness of the low refractive index layer was set so that the minimum reflectance was around 550 nm when the reflectance was measured with a spectrophotometer (manufactured by Shimadzu Corporation). A three-layer antireflection film was obtained through the above steps.

<Composition of coating liquid for low refractive index layer> Polyvinylidene fluoride containing 10% silicon (TM00
4, JSR Co., Ltd .: 2 parts by weight, dipentaerythritol pentaacrylate: 2 parts by weight, photopolymerization initiator (IRGACURE 184, Ciba Specialty Chemicals Co., Ltd.): 0.01 parts by weight, methyl isobutyl ketone : 10 parts by weight (Example 5: Preparation of three-layer antireflection film) In Example 4, instead of the titania ultrafine particle dispersion obtained in Example 1, the titania ultrafine particle dispersion obtained in Example 2 was used. A three-layer antireflection film was obtained in the same manner as in Example 6 except that the high refractive index layer was formed using.

(Comparative Example 3: Preparation of three-layer antireflection film) In Example 4, the titania ultrafine particle dispersion liquid obtained in Comparative Example 1 was used instead of the titania ultrafine particle dispersion liquid obtained in Example 1. A three-layer antireflection film was obtained in the same manner as in Example 4 except that a coating film was formed using the above.

(Comparative Example 4: Preparation of three-layer antireflection film) In Example 4, the titania ultrafine particle dispersion obtained in Comparative Example 2 was used in place of the titania ultrafine particle dispersion obtained in Example 1. A three-layer antireflection film was obtained in the same manner as in Example 4 except that a coating film was formed using the above.

Example 6 Preparation of Two-Layer Antireflection Film (6-a) Formation of High Refractive Index Layer The titania ultrafine particle dispersion obtained in Example 1 was prepared using the hard coat group prepared in Example 4. The hard coat film side of each of the materials (1), (2) and (3) is coated with a bar coater, and after drying the solvent, a UV irradiation device (fusion UV)
System Japan Co., Ltd. H bulb was used as a light source to cure at an irradiation dose of 300 mJ, and then cured in an oven.
It heated at 6 degreeC for 6 hours, and formed the high refractive index layer. The film thickness of the high refractive index layer was set so that the minimum reflectance was around 550 nm when the reflectance was measured with a spectrophotometer (manufactured by Shimadzu Corporation).

(6-b) Formation of Low Refractive Index Layer The coating liquid for low refractive index prepared in Example 4 was coated on the high refractive index layer formed in the above step with a bar coater, and a solvent was added. After drying, the H bulb of a UV irradiator (Fusion UV Systems Japan Co., Ltd.) was used as a light source to obtain 300 mJ.
And a low refractive index layer was formed. The film thickness of the low refractive index layer was set so that the minimum reflectance was around 550 nm when the reflectance was measured with a spectrophotometer (manufactured by Shimadzu Corporation). A two-layer antireflection film was obtained through the above steps.

(Example 7: Preparation of two-layer antireflection film) In Example 6, instead of the titania ultrafine particle dispersion obtained in Example 1, the titania ultrafine particle dispersion obtained in Example 2 was used. A two-layer antireflection film was obtained in the same manner as in Example 6 except that a high refractive index layer was formed using the same.

(Comparative Example 5: Preparation of a two-layer antireflection film) In Example 6, instead of the titania ultrafine particle dispersion obtained in Example 1, the titania ultrafine particle dispersion obtained in Comparative Example 1 was used. A two-layer antireflection film was obtained in the same manner as in Example 6 except that a coating film was formed using the above.

(Comparative Example 6: Preparation of two-layer antireflection film) In Example 6, the titania ultrafine particle dispersion liquid obtained in Comparative Example 2 was used instead of the titania ultrafine particle dispersion liquid obtained in Example 1. A two-layer antireflection film was obtained in the same manner as in Example 6 except that a coating film was formed using the above.

[0150] (Evaluation method) (1) Put titania ultrafine particle dispersion liquid 100 cm ³ stability measuring cylinder capacity 100 cm ³ of the dispersion was allowed to stand at 25 ° C., the supernatant 1.0 cm ³ after a predetermined time And take 1 at 120 ° C
The solid content concentration was examined from the weight difference before and after heating for an hour.
Then, the solid content concentration of the supernatant immediately after standing was set to 10
The stability was evaluated as 0% after a certain period of time. That is, it can be said that the stability of the dispersion liquid is poor because the dispersion liquid in which the solid content concentration of the supernatant liquid is large decreases easily.

(2) The coating liquid of the titania ultrafine particles of the refractive index of the coating film was coated on a silicon wafer with a spin coater, and the H bulb of a UV irradiation device (Fusion UV Systems Japan Co., Ltd.) was used as a light source. The film was cured at an irradiation dose of 500 mJ to obtain a coating film having a film thickness of 0.1 μm. The obtained coating film was heated in an oven at 40 ° C. for 6 hours to carry out a polycondensation reaction.

The refractive index of the coating film after curing was measured using a spectroscopic ellipsometer (UVISEL, manufactured by Jobin-Evon Co.) at a wavelength of 633 nm of helium neon laser light. The measurement results are shown in Table 1.

(3) Gel Fraction of Coating Film The titania ultrafine particle dispersion liquid was coated on a PET substrate having a thickness of 188 μm by a bar coater so that the coating amount was 0.2 g / m ^2, and the temperature was 120 ° C. After being heated for 2 minutes at 1.0, it was peeled off from the PET base material, and 1.0 g was filled in a cylindrical filter paper which was weighed in advance.
Next, the cylindrical filter paper was set in a Soxhlet extractor and extracted with methyl isobutyl ketone at 80 ° C. for 24 hours.
After the extraction treatment, the cylindrical filter paper was dried, and the gel fraction was calculated from the weight of the residue remaining inside the filter paper by the following formula. Gel fraction (%) = remaining amount after extraction (g) / filling amount before extraction (g) × 100 (4) Breaking strength of coating film Using titania ultrafine particle dispersion, No. 1 based on JIS K7113 A test piece was prepared and the breaking strength was measured with a tensile tester (Instron 5565, manufactured by Inslon). Further, the breaking strength of the test piece using the coating composition of Example 1 and the test piece using the coating composition of Comparative Example 2 having the same composition as in Example 1 but without preliminarily preparing the composite. Regarding the breaking strength of, the ratio when the breaking strength of the test piece using the coating composition of Comparative Example 1 having a composition obtained by removing the metal compound from the coating composition of Example 1 was set to 1 was calculated. It is considered that the larger the ratio, the more uniform the distribution of the metal compound, and the more cross-linking bonds are formed between the binders.

(5) Total light transmittance Using a spectrophotometer, based on the test method for the total light transmittance of transparent materials specified in JIS K 7361-1, the total light transmittance of a coating film including a base material is measured. The rate was determined.

(6) Coating Hardness With respect to the antireflection film produced in each Example and each Comparative Example,
A pencil hardness test based on JIS K5600-5-4 was conducted, and a portion where no scratch could be visually confirmed under a load of 1 Kg was marked with the corresponding pencil type.

(7) Adhesion Test Regarding the antireflection films produced in each Example and each Comparative Example,
A cellophane tape peeling test (cross-cut method) based on the cross-cut method based on JIS K5600-5-6 was performed to confirm the presence or absence of peeling.

(Evaluation Results) (1) Stability of Dispersion Liquid Table 1 shows the stability of the titania ultrafine particle dispersion liquids obtained in Examples 1 to 3 and Comparative Examples 1 and 2.

[0158]

[Table 1]

(2) Refractive Index of Coated Film Table 2 shows the refractive index of the coating film prepared by using the titania ultrafine particle dispersions obtained in Examples 1 to 3 and Comparative Examples 1 and 2.

[0160]

[Table 2]

(3) Gel Fraction of Coating Film Table 3 shows the gel fraction of coating films prepared by using the titania ultrafine particle dispersions obtained in Examples 1 to 3 and Comparative Examples 1 and 2. .

[0162]

[Table 3]

(4) Breaking Strength of Coating Film Breaking strength of test pieces prepared using the titania ultrafine particle dispersions obtained in Examples 1 to 3 and Comparative Examples 1 and 2, and the test piece of Comparative Example 1 Table 4 shows the ratio of the breaking strength of the other test pieces to the breaking strength of.

[0164]

[Table 4]

(5) reflectance, total light transmittance, coating film hardness,
Table 3 shows the layer constitution, minimum reflectance, total light transmittance, coating film hardness and adhesion of the three-layer antireflection coatings obtained in Examples 4 to 5 and Comparative Examples 3 to 4. Table 6 shows the layer structure, minimum reflectance, total light transmittance, coating film hardness and adhesion of the two-layer antireflection films obtained in Examples 6 to 7 and Comparative Examples 5 to 6.

[0166]

[Table 5]

[0167]

[Table 6]

*: Coating liquid for low refractive index prepared in Example 4 (4-f)

[0169]

[Table 7]

[0170]

[Table 8]

*: Coating liquid for low refractive index prepared in Example 4 (4-f)

[0172]

As described above, the high refractive index coating composition according to the present invention is a milky white liquid, can maintain a stable solution state for several months, and has a long pot life, It has good wettability to the substrate and excellent coating suitability.

In particular, the high refractive index coating composition according to the present invention assists the binder component for imparting film-forming property and adhesion to the coating film, and the refractive index increasing and adjusting action by the ultrafine metal oxide particles. Since it is used in the form of a composite by cross-linking with a metal compound for the purpose of preventing the aggregation of the metal compound or its polycondensate, the uniformity of the coating composition, and the use of the coating composition. The optical uniformity and film strength of the formed coating film can be sufficiently improved.

By the coating method using this coating composition, it is possible to mass-produce a coating film having a high refractive index and high quality at a low cost.

The high refractive index coating film according to the present invention is formed by using the above high refractive index coating composition according to the present invention, and has good adhesion to a substrate, a low refractive index layer and the like. It has excellent coating film strength, high refractive index, and is substantially transparent, and can be suitably used as a high refractive index layer or a medium refractive index layer of an antireflection film. The antireflection film containing the high refractive index coating film according to the present invention is a liquid crystal display device or C
It is preferably applied to a display surface such as an RT.

[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 high refractive index coating film according to the present invention, and a diagram schematically showing a cross section thereof.

FIG. 2 is an example of an alignment plate provided with a multilayer antireflection film including a high refractive index coating film according to the present invention, and a diagram schematically showing a cross section thereof.

FIG. 3 is an example of an antireflection film including a high-refractive index coating film according to the present invention, and is a diagram schematically showing a cross section thereof.

[Explanation of symbols]

101 ... Liquid crystal display device 102 ... Antireflection film 1 ... Glass substrate on display 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 15 ... Adhesive layer 16 ... Hard coat layer 17 ... Multilayer antireflection film 18 ... Middle refractive index layer 19 ... High refractive index layer 20 ... Low refractive index layer 21 ... Base film 22 ... High refractive index layer 23 ... Low refractive index layer

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2K009 AA03 AA05 AA06 AA15 BB11                       CC09 CC24 CC26 CC42 DD02                       DD05                 4F100 AA17A AK01A AT00B BA02                       CA23A CA23H EH46 EJ05A                       GB41 JK12 JN18                 4J038 FA011 FA111 FA221 GA03                       HA216 JC32 JC38 KA06                       KA20

Claims (28)

[Claims] 1. At least (a) an average particle size of 1 to 2
From ultrafine metal oxide particles having a refractive index of 1.60 or more at 00 nm, (b) a complex in which the molecules of a binder component having a hydrogen bond-forming group are crosslinked through a metal compound, and (c) a solvent A high-refractive-index coating composition comprising: 2. The high-refractive-index coating composition according to claim 1, wherein the metal compound forming the composite is capable of undergoing a polycondensation reaction between the metal compounds. 3. The high refractive index according to claim 2, wherein the metal compound forming the composite is partially hydrolyzed and / or polycondensed between the metal compounds. Coating composition. 4. The compound according to claim 2, wherein the metal compound is a compound selected from the group consisting of an alkoxide having two or more alkoxyl groups directly bonded to a metal atom, and a chelate thereof. The high refractive index coating composition according to. 5. The metal compound is titanium alkoxide, zirconium alkoxide, silicon alkoxide,
Silane coupling agent and chelate thereof,
The high refractive index coating composition according to claim 4, which is a compound selected from the group consisting of: 6. A compound selected from the group consisting of alkanolamines, glycols, acetylacetone, and ethyl acetoacetate, each of which has a molecular weight of 10,000 or less, as the chelating agent forming the chelate. The high refractive index coating composition according to claim 4 or 5, wherein 7. The high refractive index according to claim 4, wherein the chelate contains 0.1 to 2 moles of a chelating agent per 1 mole of metal atom of the metal compound. Coating composition. 8. The high refractive index coating composition according to claim 1, wherein a crosslink bond is formed between the hydrogen bond forming group of the binder component and the metal compound. object. 9. The high refractive index coating composition according to claim 1, wherein the hydrogen bond forming group of the binder component is a hydroxyl group. 10. A gel fraction of 10% when applied at a coating amount of 0.2 g / m ² and heated at 120 ° C. for 2 minutes.
It is above, The high refractive index coating composition in any one of Claim 1 thru | or 9 characterized by the above-mentioned. 11. The high refractive index coating composition according to claim 1, wherein at least a part of the binder component is a compound having two or more polymerizable groups in one molecule. . 12. The high refractive index coating composition according to claim 11, wherein at least a part of the binder component is a compound having two or more photopolymerizable groups in one molecule. 13. The above-mentioned complex is prepared by reacting a binder component (b1) having a hydroxyl group as a hydrogen bond-forming group with an alkoxide having two or more alkoxyl groups directly bonded to a metal atom or a chelate (b2) thereof. The high refractive index coating composition according to any one of claims 1 to 12, which is crosslinked at an equivalent ratio (b2 / b1) of 1 or less. 14. The metal oxide ultrafine particles are contained as an essential component in an amount of 10 to 10 with respect to the total weight of the components excluding the solvent.
The high-refractive-index coating composition according to any one of claims 1 to 13, characterized in that it contains 95% by weight of the composite in an amount of 5 to 90% by weight, and optionally contains other components. object. 15. The reaction equivalence ratio (b2 //) of an alkoxide having at least two alkoxyl groups directly bonded to a metal atom or a chelate (b2) thereof to the binder component (b1) having a hydroxyl group as a hydrogen bond-forming group. b1)
After the polycondensation reaction is limited to 1 or less, the complex between the molecules of the binder component having a hydrogen bond-forming group is crosslinked through the metal compound, and then at least (a) the average particle size is Refractive index of 1.60 at 1 to 200 nm
The above metal oxide ultrafine particles, (b) the composite, and
(C) A method for producing a high refractive index coating composition, which comprises mixing a solvent. 16. At least (a) an average particle size of 1 to 2
Ultrafine metal oxide particles having a refractive index of 1.60 or more at 00 nm, (b1) a binder component having a hydroxyl group as a hydrogen bond forming group, (b2) an alkoxide having two or more alkoxyl groups directly bonded to a metal atom, or a chelate thereof. Reaction equivalent ratio (b2 /
b1) and an amount of 1 or less, and (c) a solvent are mixed to prepare a mixture, and then the binder component and the metal compound or a chelate thereof are polycondensed in the mixture to form a hydrogen bond. A method for producing a high refractive index coating composition, which comprises forming a complex in which the molecules of a binder component having a group are crosslinked through a metal compound. 17. A high-refractive-index coating film obtained by applying the high-refractive-index coating composition according to any one of claims 1 to 14 onto the surface of an article to be coated. 18. A high-refractive-index coating composition obtained by applying the high refractive index coating composition according to claim 12 on the surface of an article to be coated, drying and photocuring, and then heating at 30 ° C. or higher for 1 hour or longer. Refractive index coating. 19. When a coating film test piece is prepared based on JIS K7113 using the high refractive index coating composition, and a breaking strength is measured by a tensile test, a metal is removed from the high refractive index coating composition. Using a coating composition having a composition excluding the compound as a comparative sample, the breaking strength measured by the same tensile test was 1.
The high refractive index coating film according to claim 17 or 18, which has a breaking strength value of 3 times or more. 20. An ultrafine metal oxide particle having an average particle diameter of 1 to 200 nm and a refractive index of 1.60 or more in a binder obtained by crosslinking a polymer having a hydrogen bond forming group with a metal compound or a polycondensate thereof. A high refractive index coating film characterized by being dispersed. 21. The high-refractive index according to claim 20, wherein the binder forms a cross-linkage between the metal compound or a polycondensate thereof and a hydrogen bond-forming group of the polymer. Rate coating. 22. The metal compound is titanium alkoxide, zirconium alkoxide, silicon alkoxide,
Silane coupling agent and chelate thereof,
22. The high refractive index coating film according to claim 20, which is a compound selected from the group consisting of: 23. The high refractive index coating film according to claim 20, wherein the binder further has a cross-linking bond that directly bonds the polymers having the hydrogen bond forming group. . 24. The high refractive index coating film according to claim 17, which has a refractive index of 1.65 or more. 25. Directly on the substrate or through another layer.
After coating and curing to a final film thickness of 1 μm, JIS K
The high-refractive index coating film according to any one of claims 17 to 24, characterized in that the coating film strength measured by a pencil hardness test based on 5600 under a load of 1 Kg is H or more. 26. The light transmitting layer according to claim 17, wherein two or more light transmitting layers having light transmitting properties and different refractive indexes are laminated, at least one of the light transmitting layers. An antireflection film, which is a high refractive index coating film. 27. An image display device having a display surface covered with an antireflection film, wherein the antireflection film is formed by laminating two or more light transmission layers having light transmission properties and different refractive indexes from each other. An image display device, wherein at least one of the light transmitting layers is the high refractive index coating film according to any one of claims 17 to 25. 28. Two or more light-transmitting layers having light-transmitting properties and different refractive indexes are laminated on one surface side of the light-transmitting substrate film, and at least one of the light-transmitting layers is formed. An antireflection film, one of which is the high refractive index coating film according to any one of claims 17 to 25.