JP2002006104A - High refractive index coating composition, high refractive index coated film, image display device and antireflecting film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating material that can form a high quality thin film with a high refractive index, a coated film formed by using the coating material, an antireflecting film in which the coated film is used, and an image display device to which the antireflecting film is applied. SOLUTION: The high refractive index coating composition contains (1) metal oxide superfine particles with an average particle diameter of 1200 nm and a refractive index 1.60 or more, (2) a binder component possessing a hydrogen bond-forming group, (3) a metal compound which can form cross-linking between molecules of the binder component and (4) a solvent. The high refractive index coated film formed by using this coating composition is suitable for forming, among others, a high refractive index layer 19 which is one of the layers constituting a mono-layer type or a multi-layer type antireflecting film 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

It has been conventionally known that the reflectance is reduced by coating the surface of a transparent object with a transparent film having a small refractive index, and a high refractive index layer or a medium refractive index layer is formed on the display surface of an image display device. Is formed, and a low-refractive-index layer is further formed thereon to prevent reflection.

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

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

[0006] On the other hand, when the spraying method is used as a coating method, there are problems such as poor utilization efficiency of the coating liquid and difficulty in controlling film forming conditions. In the case of using the immersion method or the screen printing method, the use efficiency of the film forming material is good, and there are advantages in mass production and equipment cost. The refractive index layer has a problem that its function and quality are inferior to those obtained by a gas phase method.

[0007] In recent years, as a coating method capable of forming a thin film of a high refractive index layer and a medium refractive index layer having excellent quality, ultrafine particles of high refractive index such as titanium oxide and tin oxide are dispersed in a solution of a binder composed of an organic substance. There has been proposed a method of applying a dispersed coating liquid on a substrate to form a coating film. In this method, it is necessary to add a large amount of high refractive index ultrafine particles to the binder solution in order to increase the refractive index. Since a strong agglomerate is generated and the stability of the coating liquid is impaired, there is a problem that the addition amount of the high refractive index ultrafine particles is limited.

Further, a method has been proposed in which a hydrolyzate of a metal compound such as a metal alkoxide is applied onto a substrate to form a high refractive index thin film such as a titania thin film. Since the coating film generated from the hydrolyzate of the metal compound contains almost no organic matter, a coating film having a high refractive index can be easily obtained as compared with a coating film formed using the dispersion liquid of the high refractive index ultrafine particles. . However, the 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 the film is easily peeled off at the boundary between the substrate and the low-refractive-index layer after film formation.

[0009]

SUMMARY OF THE INVENTION The present invention has been accomplished in view of the above circumstances, and a first object of the present invention 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 suitably used for forming an antireflection film. A third object of the present invention is to provide an antireflection film suitably applied to a display surface of an image display device. A fourth object of the present invention is to provide an image display device having a display surface covered with such an antireflection film. The present invention
Solve at least one of these objectives.

[0010]

The high refractive index coating composition according to the present invention comprises at least (1) ultrafine metal oxide particles having an average particle diameter of 1 to 200 nm and a refractive index of 1.60 or more; (3) a binder component having a hydrogen bond-forming group, (3) a metal compound capable of forming a cross-link between molecules of the binder component, and (4) a solvent.

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 a hydrogen bond forming group of the binder component. Disperses uniformly and has excellent dispersion stability. In addition, the metal compound may be condensed with two or more binder components in the state of a single molecule or a polycondensate, or may be formed by polymerization of the binder component.
It condenses with the above binder molecules to form crosslinks between the molecules of the binder. The metal compound removes an organic group in such a crosslinking reaction and a polycondensation reaction, and changes into a reaction product (crosslinked structure, polycondensed structure) having a large refractive index and good transparency. The refractive index coating composition can form a coating film having a higher refractive index than when the metal compound is not blended. 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 formed by polymerization of the binder component, so that the coating film strength is not reduced, but rather the coating film strength is reduced. May improve. Therefore, the high refractive index coating composition according to the present invention can form a coating film having the same or higher coating strength as compared with the case where the metal compound is not blended.

It is preferable that the metal compound be capable of forming a cross-linking between the molecules of the binder component and be capable of polycondensation between the metal compounds, because the coating film strength is improved. As the metal compound capable of polycondensation itself, a compound selected from the group consisting of alkoxides having two or more alkoxyl groups directly bonded to metal atoms, and chelates thereof can be used. Particularly preferred are titanium alkoxide, zirconium alkoxide,
And a chelate thereof, and a metal compound selected from the group consisting of:

The chelating agent forming the chelated product is 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 contains 0.1 to 2 mol of a chelating agent per 1 mol of a metal atom of the metal compound.

At least a part of the binder component is
A compound having two or more polymerizable groups in one molecule is preferable. By using a bifunctional or higher polyfunctional monomer as the binder component, the binder molecules are not only crosslinked via a metal compound or a condensate thereof, but also directly crosslinked, so that the coating film strength is improved.

The hydrogen bond forming group of the binder component is
The functional group is preferably a functional group capable of forming a crosslink with the metal compound.

In the high refractive index coating composition of the present invention, 10 to 80% by weight of the ultrafine metal oxide particles and 0.1% of the binder component are essential components based on the total weight of the components excluding the solvent. And 50 to 50% by weight, and 0.1 to 50% by weight in terms of a solid content remaining after heating the metal compound at 200 ° C. for 1 hour in the air, and other components as necessary. Is preferred. If the mixing ratio of any of the essential components is out of this range, either the coating strength or the refractive index often becomes insufficient.

The high refractive index coating composition of the present invention is applied so as to have a coating amount of 0.2 g / m ² ,
It is preferable that the gel fraction when heated for 10 minutes is 10% or more. When the gel fraction is 10% or more, it can be said that a sufficient amount of cross-linking via the metal compound or its polycondensate is formed between the molecules of the binder component. Does not occur.

The first high-refractive-index coating film according to the present invention is obtained by applying the above-mentioned high-refractive-index coating composition on a substrate, drying and photo-curing, and then heating at 30 ° C. or more for 1 hour or more. It is obtained by doing.

The second high refractive index coating film according to the present invention has a mean particle diameter 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 using the high-refractive-index coating composition according to the present invention. Is excellent, the coating film strength is excellent, the refractive index is high, the transparent film is substantially transparent, and it can be suitably used as a layer constituting an antireflection film, particularly 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. In addition, the high refractive index coating film according to the present invention has a high refractive index of 0.1 μm on the substrate directly or via another layer.
After coating and curing to a final film thickness of 1 μm, JIS K
The coating film strength measured with a 1 kg load by a pencil hardness test based on 5600 can be H or more.

The antireflection film according to the present invention is formed by laminating two or more light transmitting layers having light transmittance and different in refractive index from each other, and at least one of the light transmitting layers is according to the present invention. The high refractive index coating film is characterized.

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

An image display device according to the present invention is an image display device having a display surface covered with an anti-reflection film, wherein the anti-reflection film has a light-transmitting layer 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 comprises:
On one side of a base film having light transmittance, two or more light-transmitting layers having light-transmitting properties and having different refractive indexes are laminated, and at least one of the light-transmitting layers is used in the present invention. Such a high refractive index coating film is characterized.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present specification, the coating composition belonging to the present invention, and the coating film belonging 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 description of the invention, and the scope of the coating composition and the coating film belonging to the present invention is not limited by the term “high refractive index”.

The high refractive index coating composition according to the present invention has at least the following essential components: (1) an average particle diameter of 1 to 200 nm and a refractive index of 1.60.
Coating comprising the above ultrafine metal oxide particles, (2) a binder component having a hydrogen bond-forming group, (3) a metal compound capable of forming a cross-linking between molecules of the binder component, and (4) a solvent. It is a material and may contain other components as needed. 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 is particularly suitable for forming a high refractive index layer of a multilayer antireflection film.

Of the above essential components, ultrafine metal oxide particles are the main components for imparting a high refractive index to the high refractive index coating composition. Metal oxide has a high refractive index,
And because it is colorless or hardly colored,
It is suitable as a component for providing a high refractive index. The reason why the ultrafine particles of the metal oxide are used in the present invention is that transparency is not reduced when the particles of the metal oxide are dispersed in a coating film having a high refractive index. Here, "ultra fine particles"
Generally, particles on the order of submicron, and are generally called "fine particles" from several micrometers to several hundred micrometers.
It means that the particle size is smaller than the particles having a particle size of m.

The ultrafine metal oxide particles have an average particle diameter of 1n.
m or more, preferably 10 nm or more, and 200
nm, preferably 150 nm or less.
When the average particle diameter is less than 1 nm, it is difficult to uniformly disperse the compound in the high refractive index coating composition, and as a result, a coating film in which metal oxide particles are uniformly dispersed cannot be obtained. Further, those having an average particle diameter of more than 200 nm are not preferred because they impair the transparency of the coating film. The average particle diameter of the metal oxide ultrafine particles is determined by scanning electron microscope (SEM)
Or the like, or may be mechanically measured by a particle size distribution meter using a dynamic light scattering method, a static light scattering method, or the like.

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

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 high refractive index layer of an antireflection film can be formed. Further, by blending ultrafine metal oxide particles having a refractive index of 1.80 or more with 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. Therefore, the refractive index of the coating film cannot be sufficiently increased only by dispersing the metal oxide ultrafine particles in the binder, but the coating composition according to the present invention is required to have a considerably high refractive index in design. However, a coating film having a high refractive index that meets the conditions can be formed.

As the ultrafine metal oxide particles having a refractive index of 1.60 or more, for example, titanium oxide, zirconium oxide,
Zinc oxide, cerium oxide, tin-doped indium oxide (I
Ultrafine particles of metal oxides such as TO), tin-doped antimony oxide (ATO), and tin oxide can be used. When conductive fine particles such as ITO, ATO, and tin oxide are used as the metal oxide ultrafine particles, it is possible to impart antistatic performance to the high refractive index coating film. It can be particularly preferably used when it is desired to prevent adhesion or when it is desired to prevent driving failure of the liquid crystal caused by charging on the panel.

The binder component having a hydrogen bond-forming group is blended as an essential component in order to give the high refractive index coating composition according to the present invention film formability and adhesion to a substrate and a low refractive index layer. You.

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 metal oxide ultrafine particles is improved and the metal oxide ultrafine particles can be uniformly dispersed. Moisture is adsorbed on the surface of the metal oxide ultrafine particles to form hydroxyl groups, and since the hydroxyl groups form hydrogen bonds with the hydrogen bond forming groups of the binder component, the wettability of the metal oxide ultrafine particles to the binder component is improved. It is presumed that the dispersion stability of the metal oxide ultrafine particles is improved.

The hydrogen bond-forming group of the binder component may be a polar group having no chemical reactivity, but it undergoes a condensation reaction with a metal compound described later to form a metal compound or its condensation between the binder molecules. It is preferably a functional group capable of forming a crosslinked structure via a substance. The metal compound, which is one of the essential components, may be cross-linked 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 metal oxide ultrafine particles, and a metal compound. When the cross-linking bond forming groups forming the cross-linking bond are the same functional group, the binder component has a simple molecular structure, so that it is easy to obtain and handle.

The binder component may be a monomer that has not yet been polymerized or a polymer that has already been polymerized, as long as it has a hydrogen bond-forming group. From the viewpoint of imparting excellent coating properties to the coating composition, it is preferable to use a monomer as a binder component and polymerize it by a suitable method such as photopolymerization after coating 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, acrylamide; diacrylates such as pentaerythritol triacrylate, ethylene glycol diacrylate, pentaerythritol diacrylate monostearate; trimethylolpropane triacrylate, pentaerythritol triacrylate Such as tri (meth) acrylate, pentaerythritol tetraacrylate derivatives and dipentaerythritol Polyfunctional (meth) acrylates such Lumpur pentaacrylate are preferred. Here, “(meth) acrylate” means acrylate and / or methacrylate. Specific examples of the polymer used as the binder component include, in addition to the polymer of one or more monomers exemplified above, a phenol resin, a urea resin, a diallyl phthalate resin, a melamine resin, a guanamine resin, and an unsaturated polyester. Resins, polyamide resins, polyimide resins, polyurethane resins, epoxy resins, amino alkyd resins, melamine-urea co-condensation resins, silicon resins, polysiloxane resins, and the like can be given.

As the monomer as a binder component, it is preferable to use a compound having two or more polymerizable groups such as a vinylic double bond in one molecule, that is, a polyfunctional monomer having two or more functional groups from the viewpoint of coating film strength. . By using a polyfunctional monomer having two or more functional groups, the binder molecules are crosslinked via a metal compound or a condensate thereof and further directly crosslinked, so that the coating film strength is improved.

The metal compound capable of forming a crosslink between the molecules of the binder component is one of the essential components of the high refractive index coating composition according to the present invention, and is formed using the high refractive index coating composition. It is used to increase or adjust the refractive index of the coated film to a desired value, and to prevent or reduce the strength of the coated film.

The above-mentioned metal oxide ultrafine particles are a main component for increasing the refractive index. As the blending ratio of the metal oxide ultrafine particles in the coating composition increases, the refractive index increases, and the metal oxide ultrafine particles increase. Although it approaches the refractive index of itself, if the blending ratio of the metal oxide ultrafine particles is too large, the amount of the binder component becomes insufficient, so that the strength of the coating film and the adhesion are reduced. Therefore, the blending amount of the metal oxide ultrafine particles 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 molecules of a binder component as an auxiliary component for increasing and adjusting the refractive index. Is blended. The metal compound may be used in the form of a single molecule or a polycondensate.
It condenses with the above-mentioned binder component or condenses with two or more binder molecules generated by polymerization of the binder component to form a cross-linking between the molecules of the binder. The metal compound removes an organic group in such a crosslinking reaction and a polycondensation reaction, and changes into a reaction product (crosslinked structure, polycondensed structure) having a large refractive index and good transparency. The refractive index coating composition can form a coating film having a higher refractive index than when the metal compound is not blended. 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 formed by polymerization of the binder component, so that the coating film strength is not reduced, but rather the coating film strength is reduced. May improve. Therefore, the high refractive index coating composition according to the present invention can form a coating film having the same or higher coating strength as compared with the case where the metal compound is not blended.

It is preferable that the metal compound be capable of forming a cross-linking between the molecules of the binder component and be capable of polycondensation between the metal compounds because the coating film strength is improved. It is preferable to use a metal compound capable of forming a cross-linking bond with the hydrogen bond-forming group of the binder component, since it is not necessary to use a binder component having a complicated molecular structure. Further, when the metal compound has a functional group capable of forming a cross-linking bond with the hydrogen bond forming group of the binder component and capable of polycondensing the metal compounds, the molecular structure of the metal compound is Since it is relatively simple, it is preferable because it is easy to obtain and handle.

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 (wherein, 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 chloro atom, an ester group, and an amide group. The metal compound belonging to the above formula (1) includes an alkoxide having two or more alkoxyl groups directly bonded to a metal atom, or a chelated product thereof. Preferred metal compounds include titanium alkoxides, zirconium alkoxides, and chelates thereof from the viewpoints of the reinforcing effect of the refractive index and coating film strength, ease of handling, material cost, and the like. Note that titanium alkoxide and zirconium alkoxide are also raw material compounds of titanium oxide and zirconium oxide, which are preferred ultrafine metal oxide particles. When an alkoxide or a chelated product thereof corresponding to the raw material of the metal oxide ultrafine particles to be used can be obtained, the alkoxide or the chelated product corresponding to the metal oxide ultrafine particles is usually used as the metal compound as an auxiliary component. 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 having 1 to 1 carbon atoms.
Represents 10 alkyl groups. Specifically, tetramethoxytitanium, tetraethoxytitanium, tetra-iso-propoxytitanium, tetra-n
-Propoxytitanium, tetra-n-butoxytitanium, tetra-sec-butoxytitanium, tetra-tert-butoxytitanium and the like.

Zirconium alkoxide is a compound represented by the following formula (3). Formula (3): Zr (OR) ₄ (R in Formula (3) is an alkyl group, preferably having 1 to 1 carbon atoms.
Represents 10 alkyl groups. Specifically, tetramethoxy zirconium, tetraethoxy zirconium, tetra-iso-propoxy zirconium, tetra-n-propoxy zirconium, tetra-n-butoxy zirconium, tetra-sec-butoxy zirconium, tetra-tert-butoxy zirconium, etc. No.

Preferred chelating agents for forming a chelate by coordination with a free metal compound include alkanolamines such as diethanolamine and triethanolamine; glycols such as ethylene glycol, diethylene glycol and propylene glycol; acetylacetone 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 that is stable against mixing of water and the like and is excellent in the effect of reinforcing the coating film.

The above-mentioned chelating agent is preferably used in a ratio of 0.1 mol to 2 mol per 1 mol of the metal atom of the free metal compound which coordinates the chelating agent. When the proportion of the chelating agent is less than 0.1 mol, the effect of stabilization is insufficient. If the ratio of the chelating agent is more than 2 mol, the chelating agent not consumed for the formation of the chelate exists in the solution as an impurity of the organic substance, so that the strength and the transparency of the coating film are liable to decrease.

The above-mentioned metal compound has an effect of crosslinking or polycondensation between the molecules of the binder component even when used as it is. However, if necessary, a partial hydrolysis treatment may be performed intentionally to improve the effect. A strong and high-refractive-index coating film can be formed. The partial hydrolysis treatment of the metal compound
It may be performed before mixing with other components, or may be performed after mixing.

The preferred metal compounds mentioned above, ie titanium alkoxide, zirconium alkoxide or
When the chelate is partially hydrolyzed, it is preferable to add water in an amount of 2 mol or less per 1 mol of the metal compound. If more than 2 mole times of water is added to these metal compounds, hydrolysis proceeds excessively, and the stability of the coating composition and the adhesion of the resulting coating film are extremely reduced, which is not preferable.

The partial hydrolysis is usually performed 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 30 ° C. or lower.
This is carried out with continuous stirring for at least one minute and usually at most three hours, preferably at most one hour.

For the partial hydrolysis, a dilute acid catalyst can be used. Preferred acid catalysts include, for example, hydrochloric acid,
Acids such as nitric acid, sulfuric acid, or acetic acid can be used.
These acids are used in an amount of usually 0.001 N or more, preferably 0.1 N or more.
005N or more and usually 20.0N or less, preferably 1N or less, and added to a metal compound before mixing with other components or a mixture of a metal compound and other components. Of water is used for hydrolysis. Depending on the conditions, it may not be necessary to add more water.

The high refractive index coating composition of the present invention may contain other components, if necessary, in addition to the above essential components. As the desired component, for example, a photopolymerization initiator is used when the binder component is to be photopolymerized, or a dispersant is used when the dispersibility of the metal oxide ultrafine particles is to be improved.

As the photopolymerization initiator, 1-hydroxycyclohexylphenyl 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.

When a heating means is used for the curing treatment, a thermal polymerization initiator such as benzoyl peroxide which generates radicals by heating to start polymerization of the polymerizable compound is added. Is also good.

As the dispersant, an optimal 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 there is a polar group such as an ethylene oxide chain, it is preferable to use a dispersant having an anionic group such as a phosphoric acid group, a sulfonic acid group, an amino group, and an ammonium group in the molecular chain and the terminal. preferable. Such a dispersant is preferably used because it is selectively adsorbed on the surface of the metal oxide ultrafine particles to improve affinity with the binder component and prevent reaggregation of the ultrafine particles.

Solvents for dissolving or dispersing each of the above essential components and other components used as required are not particularly limited. For example, alcohols such as isopropyl alcohol, methanol and ethanol; methyl ethyl ketone and methyl isobutyl ketone; 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 appropriately adjusted. Preferably, the metal oxide ultrafine particles as an essential component are added to the total weight of the mixing components excluding the solvent.
To 80% by weight, 0.1 to 50% by weight of the binder component, and 0.1% by converting the metal compound into a solid content remaining after heating the metal compound in air at 200 ° C. for 1 hour. It is preferable that the portion containing less than 50% by weight and less than the total amount has a composition occupied by a dispersant and other components incorporated as necessary. If the mixing ratio of any of the essential components is out of this range, either the coating strength or the refractive index often becomes 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 the metal oxide ultrafine 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 only by adding a small amount of a dispersant.

The amount of the solvent is such that each component is uniformly dissolved,
It is appropriately adjusted so that it can be dispersed, does not cause agglomeration during storage after preparation, and has a concentration that is not too low during coating. Prepare a high-concentration coating composition by reducing the amount of solvent used within the range that satisfies this condition, store it in a state that does not take up the volume, take out the necessary amount at the time of use, and obtain a concentration suitable for coating work It is preferred to dilute.

In order to prepare the high refractive index coating composition according to the present invention using the above components, dispersion treatment may be performed according to a general method for preparing a coating solution. For example, by mixing each essential component and each desired component in an arbitrary order, adding a medium such as beads to the obtained mixture, and appropriately dispersing the mixture with a paint shaker, a bead mill, or the like, thereby obtaining a high refractive index coating composition. Is obtained.

The high refractive index coating composition thus obtained comprises metal oxide ultrafine particles, a binder component having a hydrogen bond-forming group, a metal compound capable of forming a crosslink between molecules of the binder component, and Other components, such as a dispersant, are dissolved or dispersed in a solvent accordingly. In the coating composition, part or all of the metal oxide fine particles are uniformly dispersed by hydrogen bonding to the binder component, and the metal compound is usually partially hydrolyzed, but is completely hydrolyzed. You do not have to.

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. Excellent coating suitability.

In order to form a coating film having sufficient coating film strength using the high refractive index coating composition of the present invention,
It is desirable that the following conditions are satisfied. That is,
Coating amount of 0.2 g of the high refractive index coating composition of the present invention
/ M ² , 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” refers to a solvent that can uniformly dissolve the binder component in a concentration range that can be used 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 cross-linking via the metal compound or its polycondensate is formed between the molecules of the binder component. Therefore, the shortage of the coating film strength due to the shortage of the binder component does not occur.

By applying the high refractive index coating composition of the present invention to the surface of an object to be coated such as a substrate, drying, polycondensation and curing, a substantially colorless and transparent high refractive index coating film is obtained. Can be formed.

The substrate on which the high refractive index coating composition of the present invention is applied is not particularly limited. Preferred substrates include, for example, a glass plate; triacetate cellulose (TAC), polyethylene terephthalate (PET),
Films formed from various resins such as diacetyl cellulose, acetate butyrate cellulose, polyether sulfone, acrylic resin; polyurethane resin; polyester; polycarbonate; polysulfone; polyether; trimethylpentene; polyether ketone; (meth) acrylonitrile; Can be exemplified. The thickness is usually about 25 μm to 1000 μm.

The high refractive index coating composition is, for example,
Spin coating, dipping, spraying, slide coating, bar coating, roll coating, meniscus coating, flexographic printing, screen printing, bead coating, etc. it can.

After the high refractive index coating composition of the present invention is applied to the surface of an object to be coated such as a substrate at a desired coating amount, the coating is usually heated and dried by a heating means such as an oven to obtain a solvent. The hydrolysis condensation reaction proceeds while removing
The metal compound is polycondensed, and a cross-link is formed between the molecules of the binder component by the molecular structure of the metal compound or the polycondensate thereof. The polycondensation of the metal compound and the hydrolysis / condensation reaction for forming the intermolecular cross-linking of the binder component are usually performed under the condition of heating at 30 ° C. or more for 1 hour or more. When a polymer that has been polymerized from the beginning is used as the binder component, a coating film having a high refractive index is obtained when the hydrolysis-condensation reaction is completed.

When a monomer is used as the binder component, usually, after the coating film of the high refractive index coating composition is heated and dried, ultraviolet (UV) or ionizing radiation (E) is used.
B) or the like, or by polymerizing the binder component by other appropriate polymerization method to produce a high molecular binder, and then heating for a certain period of time to allow the hydrolysis and condensation reaction to proceed, and the metal compound To form an intermolecular cross-linking of the binder component. In the case of using a photopolymerizable binder component such as a monomer containing an ethylenic double bond, usually, after heating and drying the coating film, the binder component is photocured by irradiation with ionizing radiation (EB), and then The hydrolysis and condensation reaction is performed by heating at 30 ° C. or more for 1 hour or more. When the binder component is a polyfunctional monomer, a cross-linking that directly bonds between the binder molecules is also formed by a polymerization reaction between the binder components, and the coating film strength is improved. When a monomer is used as the binder component, a high refractive index coating film is obtained by completing the above-mentioned hydrolysis-condensation reaction and the polymerization reaction of the binder component.

In this way, a 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 obtained by dispersing ultrafine particles, other components may be contained as necessary. Examples of the other components include components such as a dispersant blended as needed in 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 a part of the metal oxide ultrafine particles are hydrogen bonded to a hydrogen bond forming group of the binder.

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

The metal compound has two or more of the same functional groups, and the functional groups are capable of cross-linking with the hydrogen bond-forming groups present in the polymer portion constituting the binder, and the functional groups are superposed. Condensation may be 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 through a metal compound or a polycondensate thereof, The other part reacts between the functional groups to polycondensate the metal compound to form an amorphous polycondensed portion.

For example, when an alkoxide having two or more alkoxyl groups directly bonded to a metal atom or a chelated product thereof is used as the metal compound, a part of the alkoxyl group of the metal compound becomes part of the hydrogen bond forming group of the polymer. A high-refractive-index coating film having a structure in which a part is hydrolyzed and condensed to form a cross-linking bond, and the other part is hydrolyzed and condensed between the alkoxyl groups to polycondensate an alkoxide. As an alkoxide having two or more alkoxyl groups directly bonded to a metal atom or a chelated product thereof,
Examples thereof include titanium alkoxides, zirconium alkoxides, chelates thereof, and mixtures thereof.

The high-refractive-index coating film according to the present invention has good adhesion to a substrate, a low-refractive-index layer, and the like, has excellent coating film strength, has a high refractive index, is substantially transparent, and has antireflection. It can be suitably used as a layer constituting a 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 form an antireflection film in combination with one or more layers having different refractive indexes. 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. By appropriately selecting and adjusting the type and the amount of the metal compound that crosslinks the binder component together with the type and the amount of the metal oxide ultrafine particles, the refractive index of the high refractive index layer according to the present invention is set to 1. It can be easily adjusted to a high value of 65 or more or 1.80 or more and a specific value (predetermined value) preset in relation to the refractive index of another layer such as a low refractive index layer.

Further, the adhesion of the high refractive index coating film according to the present invention is 10 × 1 specified in JIS K 5600-5-6.
When the cross-cut cellophane tape peel test of 0 was performed, 1
The number of pieces to be peeled out of the 00 grid may be 1 or less.

The coating strength of the high-refractive-index coating film according to the present invention is determined according to the JIS standard after coating or curing to a final thickness of 0.1 μm on a substrate directly or through another layer. K 5600
It can be H or more when measured with a 1 kg load by a pencil hardness test based on -5-4.

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.
In the range of 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 multilayer antireflection film formed by laminating two or more layers (light-transmitting layers) having light transmittance and different refractive indexes from each other. Can be used. The high refractive index coating film according to the present invention is mainly used as a high refractive index layer, but can also be used as a medium refractive index layer. In addition, the layer having the highest refractive index in the multilayer antireflection film is referred to as a high refractive index layer, the layer having the lowest refractive index is referred to as a low refractive index layer, and the other layers having intermediate refractive indices are referred to. It is called a medium refractive index layer.

Further, even if only a single high-refractive-index coating according to the present invention is provided on a surface coated with an anti-reflection film, for example, a display surface of an image display device, the refractive index of the coated surface itself and the refractive index of the present invention can be reduced. When the balance between the refractive indices of the high refractive index coating film is just right, an antireflection effect is obtained. Therefore, the high refractive index coating film according to the present invention may effectively function as a single-layer antireflection film in some cases.

The high refractive index coating film according to the present invention is particularly useful for image display devices such as a liquid crystal display (LCD), a cathode ray tube display (CRT), a plasma display panel (PDP), and an electroluminescence display (ELD). It is suitably used for forming at least one layer of a multilayer antireflection film covering a display surface, particularly, a high refractive index layer.

FIG. 1 schematically shows a cross section of an example (101) of a liquid crystal display device having a display surface covered with a multilayer antireflection film containing a high refractive index coating film according to the present invention. The liquid crystal display device 101 has a color filter 4 in which RGB pixel portions 2 (2R, 2G, 2B) and a black matrix layer 3 are formed on one surface of a glass substrate 1 on the display surface side.
Is provided, a transparent electrode layer 5 is provided on the pixel portion 2 of the color filter, a transparent electrode layer 7 is provided on one surface of the backlight-side glass substrate 6, and the backlight-side glass substrate and the color filter are transparent. The electrode layers 5 and 7 are opposed to each other with a predetermined gap so as to face each other, the periphery is adhered with a sealant 8, the liquid crystal L is sealed in the gap, and an alignment film 9 is formed on the outer surface of the glass substrate 6 on the back side. 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 disposed behind.

FIG. 2 schematically shows a cross section of the polarizing film 10 attached to the outer surface of the glass substrate 1 on the display surface side. In the polarizing film 10 on the display surface side, a polarizing element 12 made of polyvinyl alcohol (PVA) or the like is coated on both sides with protective films 13 and 14 made of triacetyl cellulose (TAC) or the like, and an adhesive layer 15 is provided on the back side. A hard coat layer 16 and a multilayer anti-reflection film 1717 are sequentially formed on the viewer side.
Is adhered to the glass substrate 1 on the display surface side.

In order to reduce glare by diffusing light emitted from the inside as in a liquid crystal display device or the like, the hard coat layer 16 is formed by forming the surface of the hard coat layer into an uneven shape, or An anti-glare layer (anti-glare layer) having a function of scattering light inside the hard coat layer by dispersing an inorganic or organic filler inside the hard coat layer may be used.

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 laminated. 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 shown.

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. Can be. The middle refractive index layer 18 and the high refractive index layer 19 can be formed using the high refractive index coating film according to the present invention, and the middle refractive index layer 18 has a refractive index of 1.46 to
In the range of 1.80, the high refractive index layer 19 has a refractive index of 1.6.
Five or more are used.

The antireflection film reduces the reflectance of light emitted from an external light source, thereby reducing the reflection of scenery and fluorescent lights, and improving the visibility of display. In addition, by using the hard coat layer 16 as an anti-glare layer, since straight light and external light from inside are scattered,
The glare of reflection is reduced, and the visibility of 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 so that the refractive index is 1.46 to 1.80. , A high refractive index layer 19 whose refractive index is adjusted to 1.65 or more, and a low refractive index layer 20 can be further provided. Then, the polarizing film 10 including the antireflection film 17 can be stuck on the glass substrate 1 on the viewing side via the adhesive layer 15.

On the other hand, since an alignment plate is not attached to the display surface of the CRT, it is necessary to directly provide an 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 operation.
In such a case, an anti-reflection film containing the high refractive index coating film according to the present invention is prepared, and the anti-reflection film is attached to the display surface to form an anti-reflection film. Need not be applied.

Two or more light-transmitting layers having a light-transmitting property and different refractive indexes are laminated on one surface side of a base film having a light-transmitting property, and at least one of the light-transmitting layers is provided. Is formed with the high refractive index coating film according to the present invention, whereby an antireflection film can be obtained. The base film and the light transmission layer need to have a light transmittance that can be used as a material for the antireflection film, and are preferably as transparent as possible.

FIG. 3 schematically shows a cross section of an example (102) of an antireflection film including a high refractive index coating film according to the present invention. The antireflection film 102 is formed by applying the high-refractive-index coating composition according to the present invention to one surface of the base film 21 having a light-transmitting property.
Is formed, and the low refractive index layer 23 is formed on the high refractive index layer.
Is provided. In this example, there are only two light transmission layers with different refractive indices, a high refractive index layer and a low refractive index layer,
Three or more light transmitting layers may be provided. In that case, not only the high refractive index layer but also the middle refractive index layer can be formed by applying the high refractive index coating composition according to the present invention.

[0093]

EXAMPLES (1) Preparation of High Refractive Index Coating Composition (Example 1) The following components were put into a mayonnaise bottle and shaken for 7 hours using a zirconia bead as a medium with a paint shaker to disperse titania ultrafine particles. A liquid (high refractive index coating composition) was obtained.

<Composition of Titania Ultrafine Particle Dispersion> Titania ultrafine particles (average particle diameter by scanning electron microscope observation: 30 nm, trade name: TTO51 (C), manufactured by Ishihara Techno Co., Ltd.): 10 parts by weight (Trade name: Dispervic 163, manufactured by BYK Chemie KK): 2 parts by weight ・ Pentaerythritol tetraacrylate: 10 parts by weight ・ Titanium-2-butoxide (residue amount after heating at 200 ° C. for 1 hour in the atmosphere: 0.94 g) ): 4 parts by weight Photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 0.4 parts by weight Methyl isobutyl ketone: 198 parts by weight

(Example 2) The following components were put in a mayonnaise bottle, and the mixture was shaken for 7 hours with a paint shaker using zirconia beads as a medium to partially hydrolyze titanium-2-butoxide, thereby dispersing ultrafine titania particles. (High refractive index coating composition) was obtained.

<Composition of Titania Ultrafine Particle Dispersion> Titania ultrafine particles (average particle diameter by scanning electron microscope observation: 30 nm, trade name: TTO51 (C), manufactured by Ishihara Techno Co., Ltd.): 10 parts by weight (Trade name: Dispervic 163, manufactured by BYK Chemie KK): 2 parts by weight ・ Pentaerythritol tetraacrylate: 2 parts by weight ・ Dipentaerythritol pentaacrylate: 10 parts by weight ・ Titanium-2-butoxide (at 200 ° C. in air for 1 hour) Residual amount after heating: 0.47 g): 2 parts by weight 0.1 mol / liter hydrochloric acid water: 0.01 part by weight Photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 0 0.4 parts by weight Methyl isobutyl ketone: 198 parts by weight

Example 3 The following components were put into a mayonnaise bottle, and the mixture was shaken for 7 hours with a paint shaker using zirconia beads as a medium to obtain a titania ultrafine particle dispersion (high refractive index coating composition). .

<Composition of Titania Ultrafine Particle Dispersion> Ultrafine titania particles (average particle diameter by scanning electron microscope observation: 30 nm, trade name: TTO51 (C), manufactured by Ishihara Techno Co., Ltd.): 10 parts by weight (Trade name: Dispervic 163, manufactured by Big Chemie Co., Ltd.): 2 parts by weight ・ Pentaerythritol tetraacrylate: 2 parts by weight / Chelating agent = 1/1, 20 in air
Residual amount after heating at 0 ° C. for 1 hour: 0.27 g): 2
Parts by weight Photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 0.4 parts by weight Methyl isobutyl ketone: 198 parts by weight

Comparative Example 1 The procedure of Example 1 was repeated except that no titanium-2-butoxide was added, to obtain a titania ultrafine particle dispersion containing no metal compound capable of crosslinking the binder component. Prepared. Further, using this dispersion, the same procedure as in Example 1 was carried out to produce a high refractive index coating film of Comparative Example and an antireflection film of Comparative Example.

(2) Measurement of Refractive Index of Coated Film (Example 4) The dispersion liquid of ultrafine titania particles obtained in Examples 1 to 3 was coated on a silicon wafer by a spin coater, and was applied to a UV irradiation apparatus (fusion). Using an H bulb of UV Systems Japan Co., Ltd.) as a light source, the composition was cured at an irradiation amount of 500 mJ to obtain a coating film having a 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 cured film was measured for refractive index using a spectroscopic ellipsometer (UVISEL, manufactured by Joban-Evon Co., Ltd.) at a wavelength of helium-neon laser light of 6
The refractive index at 33 nm was measured. Table 1 shows the measurement results.

(Comparative Example 2)
In the same manner as in Example 4, except that the titania ultrafine particle dispersion obtained in Comparative Example 1 was used instead of the titania ultrafine particle dispersion obtained in Comparative Examples 1 to 3, a coating film was formed. The rate was measured. Table 1 shows the measurement results.

[0103]

[Table 1]

(3) Measurement of Gel Fraction of Coated Film (Example 5) The titania ultrafine particle dispersions obtained in Examples 1 to 3 were coated on a PET substrate having a thickness of 188 μm by a coating amount of 0.2.
g / m ² with a bar coater and 120 ° C
After heating for 2 minutes at, the resin was peeled off from the PET substrate and filled in a cylindrical filter paper weighed in advance in an amount of 1.0 g. 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 by the following equation from the weight of the residue remaining inside the filter paper. Gel fraction (%) = remaining amount (g) after extraction / filling amount (g) before extraction × 100 The measurement results are shown in Table 2.

(Comparative Example 3)
In the same manner as in Example 5 except that a coating film was formed using the titania ultrafine particle dispersion obtained in Comparative Example 1 in place of the titania ultrafine particle dispersion obtained in The gel fraction was measured. Table 2 shows the measurement results.

[0106]

[Table 2]

(4) Preparation of Three-Layer Anti-Reflection Film (Example 6) (6-a) Preparation of Transparent Hard Coat Film (1) A 188 μm-thick PET base material (A-4350) having one surface treated to improve adhesion. Co., Ltd., manufactured by Toyobo Co., Ltd.) was coated with a hard coat coating solution (1) having the following composition using a bar coater, and after drying the solvent, a UV irradiation device (Fusion UV Systems Japan Co., Ltd.) Is cured with an irradiation amount of 500 mJ using the H bulb of
A μm transparent hard coat film was formed to obtain a hard coat substrate (1).

<Composition of Hard Coat Coating Solution (1)> Dipentaerythritol pentaacrylate: 7 parts by weight Colloidal silica dispersion (solid content: 25% by weight, MEK)
-ST, manufactured by Nissan Chemical Co., Ltd.): 12 parts by weight-Photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.): 0.3 parts by weight-Methyl isobutyl ketone: 20 parts by weight

(6-b) Preparation of Transparent Hard Coat Film (2) A hard coat coating solution (2) having the following composition was applied on a triacetyl cellulose substrate with a bar coater, and the solvent was dried. 300 m using the H bulb of a UV irradiation device (manufactured by Fusion UV Systems Japan Co., Ltd.) as a light source
By curing with the irradiation amount of J, a transparent hard coat film having a thickness of 4 μm was formed, and a hard coat substrate (2) was obtained.

<Composition of Hard Coat Coating Solution (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

(6-c) Preparation of Anti-Glare-Providing Hard Coat Film (3) A hard coat coating solution (3) having the following composition was applied on a triacetyl cellulose substrate with a bar coater, and the solvent was removed. After drying, 300 m using an H bulb of a UV irradiation apparatus (manufactured by Fusion UV Systems Japan) as a light source.
The composition was cured with the irradiation amount of J to form a hard coat film having a thickness of 4 μm and having an antiglare property, thereby obtaining a hard coat substrate (3).

<Composition of Hard Coat Coating Solution (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 ・ Methyl isobutyl ketone: 72.0 parts by weight

(6-d) Formation of Medium Refractive Index Layer The titania ultrafine particle dispersion obtained in Example 3 was applied to the hard coat film side of each of the hard coat substrates (1), (2) and (3). After coating with a bar coater and drying the solvent,
Using an H bulb of a UV irradiator (manufactured by Fusion UV Systems Japan Co., Ltd.) as a light source, the composition was cured with an irradiation amount of 300 mJ, and then heated in an oven at 40 ° C. for 6 hours to obtain a medium refractive index layer. The thickness of the medium refractive index layer was 550 when the reflectance was measured by a spectrophotometer (manufactured by Shimadzu Corporation).
The maximum reflectance was set near nm.

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

(6-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 by a bar coater, and the solvent was dried.
Using an H bulb of a UV irradiation apparatus (manufactured by Fusion UV Systems Japan Co., Ltd.) as a light source, the composition was cured at an irradiation amount of 300 mJ to form a low refractive index layer. The thickness of the low-refractive-index layer was set so that the minimum reflectance was near 550 nm when the reflectance was measured by a spectrophotometer (manufactured by Shimadzu Corporation). Through the above steps, a three-layer antireflection film was obtained.

<Composition of Coating Liquid for Low Refractive Index Layer> Polyvinylidene fluoride containing 10% silicon (TM00
4, JSR Corporation): 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

(Embodiment 7) In Embodiment 6, Embodiment 1
In the same manner as in Example 6, except that the titania ultrafine particle dispersion obtained in Example 2 was used instead of the titania ultrafine particle dispersion obtained in Example 2, a three-layer antireflection was performed. A membrane was obtained.

(Comparative Example 4)
The procedure of Example 6 was repeated, except that the titania ultrafine particle dispersion obtained in Comparative Example 1 was used instead of the titania ultrafine particle dispersion obtained in Example 1 to form a coating film. Obtained.

(5) Preparation of Two-Layer Anti-Reflection Film (Example 8) (8-a) Formation of High Refractive Index Layer The titania ultrafine particle dispersion obtained in Example 1 was prepared in the same manner as in Example 6. The hard coat film side of each of the coated substrates (1), (2) and (3) is coated with a bar coater, the solvent is dried, and then a UV irradiation device (fusion U)
V Systems Japan Co., Ltd.) using an H bulb as a light source and curing at an irradiation dose of 300 mJ, followed by an oven.
By heating at 0 ° C. for 6 hours, a high refractive index layer was formed. The thickness of the high refractive index layer was set so that the maximum reflectance was at around 550 nm when the reflectance was measured with a spectrophotometer (manufactured by Shimadzu Corporation).

(8-b) Formation of Low Refractive Index Layer The coating liquid for low refractive index prepared in Example 6 was coated on the high refractive index layer formed in the above step with a bar coater, and a solvent was applied. After drying, 300 mJ was measured using an H bulb of a UV irradiation device (manufactured by Fusion UV Systems Japan) as a light source.
To form a low refractive index layer. The thickness of the low-refractive-index layer was set so that the minimum reflectance was near 550 nm when the reflectance was measured by a spectrophotometer (manufactured by Shimadzu Corporation). Through the above steps, a two-layer antireflection film was obtained.

(Embodiment 9) In Embodiment 8, Embodiment 1
The procedure of Example 8 was repeated except that the titania ultrafine particle dispersion obtained in Example 2 was used instead of the titania ultrafine particle dispersion obtained in Example 2 to form a high refractive index layer. A membrane was obtained.

(Comparative Example 5) In Example 8, Example 1
The procedure of Example 8 was repeated, except that the titania ultrafine particle dispersion obtained in Comparative Example 1 was used instead of the titania ultrafine particle dispersion obtained in Example 1 to form a coating film. Obtained.

(Evaluation Method) (1) Stability of Dispersion Liquid 100 cm ³ of the titania ultrafine particle dispersion liquid was placed in a measuring cylinder having a capacity of 100 cm ³ , and allowed to stand at 25 ° C., and after a certain period of time, the supernatant liquid 1.0 cm ³ At 120 ° C
The solid content concentration was determined from the difference in weight before and after heating for an hour.
Then, the solid content concentration of the supernatant liquid immediately after standing was 10
The stability after a certain period of time was evaluated as 0%. That is, it can be said that a dispersion having a large decrease in the solid content concentration of the supernatant is liable to precipitate, and thus has poor stability.

(2) Total light transmittance Using a spectrophotometer, based on the test method for the total light transmittance of the transparent material specified in JIS K7361-1, the total light transmittance of the coating film including the base material was measured. The rate was determined.

(3) Coating strength The antireflection coatings produced in the examples and comparative examples were:
A pencil hardness test based on JIS K5600-5-4 was carried out, and where no scratches could be visually observed under a load of 1 kg was marked with a corresponding pencil type.

(4) Adhesion test Regarding the antireflection film produced in each of Examples and Comparative Examples,
A cellophane tape peeling test (cross-cut method) by a 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 Table 3 shows the stability of the titania ultrafine particle dispersions obtained in Examples 1 to 3 and Comparative Example 1.

[0128]

[Table 3]

(2) Reflectivity, total light transmittance, coating strength,
Table 4 shows the reflectance, total light transmittance, coating film hardness, and adhesion (cellotape test) of the three-layer antireflection films obtained in Examples 6 to 7 and Comparative Example 4. Table 5 shows the reflectance, total light transmittance, coating film hardness, and adhesion of the two-layer antireflection films obtained in Examples 8 to 9 and Comparative Example 5.

[0130]

[Table 4]

[0131]

[Table 5] *: Coating liquid for low refractive index prepared in Example 6 (6-f)

[0132]

[Table 6]

[0133]

[Table 7] *: Coating liquid for low refractive index prepared in Example 6 (6-f)

[0134]

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, has a long pot life, It has good wettability to the substrate and excellent application suitability. Then, by a coating method using this coating composition, a high-quality coating film having a high refractive index can be mass-produced at low cost.

The high-refractive-index coating film according to the present invention is formed using the 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. Which is excellent in coating film strength, has a high refractive index, 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 a C
It is suitably applied to a display surface such as an RT.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 ... Liquid crystal display device 102 ... Anti-reflection film 1 ... Glass substrate on display surface side 2 ... Pixel part 3 ... Black matrix layer 4 ... Color filter 5, 7 ... Transparent electrode layer 6 ... Glass substrate on back side 8 ... Seal material 9 ... Orientation 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 ... Medium 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

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C09D 185/00 C09D 201/00 201/00 C03C 17/25 Z G02B 1/10 G02B 1/10 A // C03C 17/25 Z F term (reference) 2K009 AA05 AA12 AA15 BB02 BB14 BB24 BB25 BB28 CC02 CC03 CC06 CC24 CC26 CC45 DD02 DD05 4F100 AA17A AA17H AA21A AA27A AK25A AR00C AS00A AT00B01BA01 BA01 BA01 BA01 BA01 BA01 BA01 BA01 BA01 BA01 BA01 JN18A JN18C YY00A YY00H 4G059 AA07 AA08 AC04 AC09 EA01 EA02 EA03 EA04 4J011 CA01 CA02 CA08 CC10 PA07 PA25 PA27 PA30 PA36 PB22 PB30 QA02 QA03 QA06 QA13 QA17 QA22 QA23 UA01 GW01 FA03 012 JA16 JC38 KA03 KA06 KA20 NA11 NA17 NA19 PA17 PA19 PB08 PC03

Claims (20)

[Claims] At least (1) the average particle size is 1 to 2
Ultrafine metal oxide particles having a refractive index of 1.60 or more at 00 nm, (2) a binder component having a hydrogen bond-forming group, (3) a metal compound capable of forming a cross-linking between molecules of the binder component, and ( 4) A high refractive index coating composition comprising: a solvent. 2. The high refractive index coating composition according to claim 1, wherein the metal compound is capable of undergoing a polycondensation reaction between the metal compounds. 3. The compound according to claim 2, wherein the metal compound is a compound selected from the group consisting of alkoxides having two or more alkoxyl groups directly bonded to metal atoms, and chelates thereof. High refractive index coating composition. 4. The high refractive index coating composition according to claim 3, wherein the metal compound is a compound selected from the group consisting of titanium alkoxide, zirconium alkoxide, and chelates thereof. . 5. The chelating agent forming the chelated product is a compound selected from the group consisting of alkanolamines, glycols, acetylacetone, and ethyl acetoacetate, each having a molecular weight of 10,000 or less. The high refractive index coating composition according to claim 4, wherein 6. The high refractive index coating composition according to claim 4, wherein the chelate contains 0.1 to 2 moles of a chelating agent per mole of metal atom of the metal compound. 7. 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. 8. The high refractive index coating composition according to claim 1, wherein the hydrogen bond forming group of the binder component is a functional group capable of forming a crosslink with the metal compound. 9. The method according to claim 1, wherein the total weight of the components excluding the solvent is
As an essential component, the metal oxide ultrafine particles are 10 to 80
% By weight, 0.1 to 50% by weight of the binder component, and 0.1 to 50% by weight in terms of a solid content remaining after heating the metal compound at 200 ° C. for 1 hour in the air. The high-refractive-index coating composition according to claim 1, further comprising other components according to the following. 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.
The high refractive index coating composition according to claim 1, wherein: 11. A high refractive index coating composition according to any one of claims 1 to 10, which is applied on a substrate, dried and photocured, and then heated at 30 ° C. or more for 1 hour or more. High refractive index coating. 12. A binder obtained by crosslinking a polymer having a hydrogen bond-forming group with a metal compound or a polycondensate thereof,
Characterized in that metal oxide ultrafine particles having an average particle diameter of 1 to 200 nm and a refractive index of 1.60 or more are dispersed.
High refractive index coating. 13. The high-refractive-index coating film according to claim 12, wherein the binder further has a cross-linking for directly bonding the polymers having the hydrogen bond-forming group to each other. 14. The binder uses, as the metal compound, an alkoxide having two or more alkoxyl groups directly bonded to a metal atom or a chelated product thereof, and a part of the alkoxyl group of the metal compound forms a hydrogen bond of the polymer. A part of the group is hydrolyzed and condensed to form a cross-link, and the other part is hydrolyzed and condensed between the alkoxyl groups to polycondensate the alkoxide, The high-refractive-index coating film described in the above. 15. The high-refractive-index coating film according to claim 14, wherein the metal compound is a compound selected from the group consisting of titanium alkoxide, zirconium alkoxide, and chelates thereof. 16. The high refractive index coating film according to claim 11, having a refractive index of 1.65 or more. 17. The method of claim 1 wherein the substrate is directly or via 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 11 to 16, wherein the coating film strength measured by a pencil hardness test based on 5600 under a load of 1 kg is H or more. 18. The light transmission layer according to claim 11, wherein two or more light transmission layers having light transmission properties and different refractive indices are laminated, and at least one of said light transmission layers is provided. An antireflection film, which is a high refractive index coating film. 19. An image display device having a display surface covered with an anti-reflection film, wherein the anti-reflection film is formed by laminating two or more light-transmitting layers having light transmittance 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 11 to 17. 20. One or more light-transmitting layers having light-transmitting properties and different refractive indexes are laminated on one surface side of a base film having light-transmitting property, and at least one of the light-transmitting layers is 18. An anti-reflection film, characterized in that one is the high refractive index coating film according to any one of claims 11 to 17.