JPH10319210A - Antireflection film and display device with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a low reflectance in a wide wavelength range, to improve film strength, durability, antifouling property and heat resistance and to enable low-cost production over a large area in large quantities by curing a layer contg. specified fine polymer particles, a specified binder and a polymn. initiator by irradiation with UV to form a low refractive index layer. SOLUTION: A layer contg. fine polymer particles having <=200 nm average particle diameter and polymerizable functional groups, a binder having at least one polymerizable functional group copolymerizable with the polymerizable functional groups in one molecule and a polymn. initiator is cured by irradiation with UV to form a low refractive index layer and an antireflection film with the low refractive index layer as the top layer is used. The polymn. initiator is a photopolymn. initiator which generates a polymn. initiator by irradiation with UV.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-reflection film which is excellent in mass productivity and anti-contamination properties, and at the same time, realizes high film strength, and a display device having the anti-reflection film.

[0002]

2. Description of the Related Art In recent years, with the spread of liquid crystal display devices, enlargement and outdoor use, toughness under use conditions, for example, improvement in resistance to reflected light (ensure visibility), antifouling property and heat resistance. Is required. Improving the visibility of a display device is an issue related to the main function of the device, and naturally has high importance, and measures for improving the visibility are being actively studied. Generally, visibility is reduced by the reflection of scenery due to surface reflection of external light, and as a countermeasure against this, a method of providing an antireflection film on the outermost surface is generally performed. However,
Since this antireflection film is provided on the outermost surface in order to exhibit its function, many issues of high quality are inevitably concentrated on the performance of the antireflection film from the viewpoint of toughness. For example, reduction of reflectance to the limit (reflectance of 1% or less), prevention of adhesion of fingerprints and fats and oils, easy removal, and maintenance of various performances in a high temperature environment such as under the sun or in a car interior. In general, to obtain an antireflection film, a method of providing an ultrathin layer having a refractive index as low as possible on the outermost surface of a substrate is known. As a method for providing an antireflection film having such a low refractive index layer at a low cost, and in a large amount and a method suitable for large-area production,
Japanese Patent Application No. 8-34661 describes a technique relating to an antireflection film formed by laminating fluoropolymer fine particles.
However, since the antireflection film actively reduces the refractive index of the particle laminated layer by actively leaving voids between the particles, the polymer constituting the particles necessarily has a high glass transition point to prevent deformation. It has been found that there is a problem that the film strength is reduced due to embrittlement of the film. In addition, since the fluorine content is high, the affinity between the particle surfaces or between the particle surface and the binder is poor, and these also contribute to a decrease in film strength.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to exhibit a uniformly low reflectance (reflectance of 1% or less) over a wide wavelength range, and at the same time, to obtain film strength, durability, adhesion to dirt, and heat resistance. An object of the present invention is to provide an antireflection film excellent in low cost at low cost and in a method suitable for large-scale and large-area production.

[0004]

The above-mentioned problems are solved by the following antireflection film. (1) Polymer fine particles having a polymerizable functional group having an average particle diameter of 200 nm or less, a binder having at least one polymerizable functional group copolymerizable with the polymerizable functional group in one molecule, and a polymerization initiator Wherein the layer is a low refractive index layer cured by ultraviolet irradiation. (2) The antireflection film according to the above (1), wherein the low refractive index layer contains at least 3% by volume of voids. (3) The antireflection film according to the above (1) or (2), wherein the polymerizable functional group of the fine particles is an epoxy group. (4) The antireflection film according to the above (1) or (2), wherein the reactive functional group of the fine particles is a vinyl group. (5) The antireflection film according to any one of (1) to (4), wherein the fine particles have a core-shell structure. (6) The low refractive layer thus formed contains at least 0.3% by weight or more of fluorine atoms.
(5) The antireflection film as described in (5). (7) The above (1) to (6), wherein the low refractive index layer is formed on a layer having a higher refractive index.
The antireflection film according to the above. (8) The antireflection film according to any one of (1) to (7), wherein the haze value of the antireflection film is 3 to 30%. (9) A display device provided with the antireflection film according to any one of (1) to (8).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The excellent antireflection film obtained by the antireflection film of the present invention will be described below. In the following description, voids in the antireflection film obtained by forming the fine particles having a polymerizable group of the present invention are referred to as “microvoids”.

In general, a method for providing an antireflection function by providing an ultrathin layer having a refractive index as low as possible on the outermost surface of a substrate is known. In the present invention, fine particles having a polymerizable functional group in the outermost surface layer (low refractive index layer) (hereinafter referred to as polymerizable fine particles) and a polymerizable group having a copolymerizability with the polymerizable functional group are contained in one molecule. (Hereinafter, referred to as a polymerizable binder), and a polymerization initiator (hereinafter, referred to as a photopolymerization initiator) that generates a polymerization initiator upon irradiation with ultraviolet rays. In FIG.
1 shows an antireflection film containing fine particles as a main component. In the figure, 1 is a layer (microvoid-containing layer) in which air generated by microvoids between particles is mixed with a particle-forming polymer and a binder component forming a film, and 3 is a substrate. The microvoids are uniformly dispersed in one layer. Also,
This microvoid layer is provided on the outermost surface of the transparent substrate on which antireflection is to be performed.

The fine particle layer having such a low refractive index is
Not only the single-layer film shown in FIG. 1 but also the uppermost layer of the multilayer film can be used. FIG. 2 shows an antireflection film in which a layer 2 having a refractive index higher than the refractive index of the substrate is provided on the substrate film, and the low refractive index layer of the present invention is further provided thereon. Obtaining an effective antireflection film in a wider wavelength range by forming a multilayer in this way is based on the same principle as that of the prior art. For example, JP-A-59-50401
In the two-layer film, the refractive index n ₁ and the film thickness d ₁ of the film of the first layer in contact with the base material, and the refractive index n ₂ of the second layer in contact with the first layer are different from those of the two-layer film. By making the thickness d ₂ satisfy the following relationship, the action as the antireflection film is optimized. The antireflection conditions for such a multilayer film have been known for a long time. First layer mλ / 4 × 0.7 <n ₁ d ₁ <mλ / 4 × 1.3 Second layer nλ / 4 × 0.7 <n ₂ d ₂ <nλ / 4 × 1.3 where m is A positive integer, n is an odd positive integer.

The present invention is characterized in that the microvoids carried by the polymerizable fine particles and held in the film are uniform, and that the microvoids have a size that does not scatter light. In other words, the low refractive index layer is microscopically a microvoid-containing porous film, but can be regarded as an optically or macroscopically uniform film.
For this reason, the macroscopic refractive index of the microvoided film becomes lower by an amount corresponding to the volume fraction of air introduced by converting the polymer into polymerizable fine particles. That is, the refractive index of this film is represented by the volume average of the refractive index of the binder component forming the film (having a value larger than 1) and the refractive index of the introduced air (which is 1.00). , Resulting in a value lower than the refractive index of the binder component used.

In order to form the microvoid-containing film, it is essential that the constituent fine particles are hard and the microvoids do not disappear due to particle deformation. For this reason, it is essential that the polymer component constituting the fine particles has a glass transition temperature (Tg) higher than the coating film forming temperature or the use temperature, and for such a purpose, the polymer usually has a high Tg.
Or a crosslinked monomer copolymerization is carried out. However, the film containing the hard fine particles is usually very brittle and the film quality is insufficient. Further, in order to reduce the refractive index to a level having a sufficient performance as an antireflection film, it is usually necessary to increase the fluorine content in the film as much as possible. For this reason, a material having a high fluorine content is usually used as the microvoid-containing film constituting fine particles. This is disadvantageous in terms of film quality due to insufficient properties, and the film containing fluorine-containing fine particles was insufficient in film quality.

The inventors of the present invention have introduced a polymerizable functional group into fine particles to solve the above-mentioned problems, and when used in combination with a polymerizable binder, have a microvoid-containing low refractive index layer that achieves both optical performance and film quality performance. Was obtained, and the low refractive index layer of the present invention was obtained. The particle size of the polymerizable fine particles used in the present invention is 200 nm or less. If the particle diameter increases, forward scattering increases, and if it exceeds 200 nm, the scattered light is undesirably colored. Further, preferably,
The thickness is 70 nm or less from the viewpoint of optical performance and film quality, and particularly preferably 50 nm or less. Such fine particles can be manufactured and obtained as a polymer latex.

Hereinafter, the polymerizable fine particles of the present invention will be described. The monomer forming the polymerizable fine particles of the present invention is not particularly limited as long as it has a polymerizable group,
Those having a commercially available or synthetic polymerizable unsaturated group can be suitably used. The polymerizable functional group is not particularly limited as long as it is a functional group capable of reacting with a radical initiator, a cationic initiator, or an anionic initiator to perform a polymerization reaction, and examples thereof include an epoxy group and a vinyl group. Examples of the monomer having a polymerizable functional group as described above include, but are not limited to, glycidyl acrylate having an epoxy group, glycidyl methacrylate, and allyl methacrylate having a vinyl group. From the viewpoint of lowering the refractive index of the formed low refractive index layer, it is also preferable to use a polymerizable functional group-containing monomer containing a fluorine atom.

In addition to the polymerizable functional group-containing monomer, a monomer having no polymerizable functional group may be used in combination.
In order to reduce the refractive index of the formed low refractive layer to a desired refractive index, it is preferable to use a monomer containing a fluorine atom. Specific examples of these monomers include, for example, fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoro-
2,2-dimethyl-1,3-dioxole), acrylic or methacrylic acid partially or fully fluorinated alkyl ester derivatives represented by the following general formula, fully or partially fluorinated vinyl ethers, and the like. The desired polymer can be obtained by copolymerization by combining the above monomers in an arbitrary ratio.

[0013]

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As the monomer having no polymerizable functional group, a monomer containing no fluorine atom may be used in addition to the above-mentioned fluorine-containing monomer. There is no particular limitation on the monomer units that can be used in combination, and for example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylates (methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, etc.) ), Methacrylates (such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate),
Styrene derivatives (styrene, vinyltoluene, α-methylstyrene, etc.) can be exemplified.

The refractive index of the polymer obtained when the above-mentioned fluorine-containing monomer is used decreases as the content of fluorine atoms in all the monomers used increases. In order to sufficiently lower the refractive index of the antireflection film for the purpose of the present invention, the polymer preferably contains 15% by weight to 80% by weight of fluorine atoms, particularly preferably 25% by weight to 7% by weight.
5% by weight.

In addition to the above monofunctional monomers, polyfunctional monomers can also be preferably used. The polyfunctional monomers are not particularly limited, and those having a plurality of polymerizable unsaturated groups in one molecule of a commercially available or synthesized molecule If so, this can be suitably used. From the viewpoint of lowering the refractive index of the low refractive layer to be formed, it is also preferable to use the one in which the polyfunctional monomer contains a fluorine atom. Specific examples of the above polyfunctional monomer include, for example, olefins (eg, butadiene, pentadiene, divinylcyclohexane, etc.), acrylates (ethylene glycol diacrylate, 1,4-cyclohexane diacrylate,
Dipentaerythritol hexaacrylate, etc.), methacrylates (ethylene glycol dimethacrylate, 1,2,4-cyclohexanetetramethacrylate, pentaerythritol tetramethacrylate, etc.), styrene derivatives (1,4-divinylbenzene, 4
-Vinylbenzoic acid-2-acryloylethyl ester), vinyl sulfones (such as divinyl sulfone), acrylamides (such as methylenebisacrylamide),
Methacrylamides and the like can be mentioned.

The optimum content of the polyfunctional monomer varies depending on the type and combination of the monofunctional monomers used in combination.
Preferably it is 0 to 50% by weight, more preferably 3 to 30% by weight of the copolymer component. When a monomer having a fluorine atom is used, the refractive index of the above-mentioned crosslinked polymer fine particles decreases as the content of the fluorine atom in the polymer increases.

The polymer forming the reactive fine particles of the present invention may be either crystalline or amorphous.
The glass transition point (Tg) of the fine particle polymer is not particularly limited, but Tg is preferably equal to or higher than the film forming temperature from the viewpoint of maintaining voids during film formation.

The polymerizable functional groups of the polymerizable fine particles of the present invention may be introduced in the form of core-shell structured fine particles having the above-mentioned polymerizable functional group-containing monomer as a shell component. The polymerizable functional group of the polymerizable fine particles of the present invention is preferably distributed in large amounts on the particle surface, and when introduced in the form of the core-shell fine particles, the core component does not necessarily need to contain a polymerizable functional group. . The glass transition point (Tg) of the core polymer of the core-shell fine particles is not particularly limited, but Tg is preferably equal to or higher than the film formation temperature from the viewpoint of maintaining voids during film formation. The volume fraction of the shell polymer in the core-shell fine particles is not particularly limited. However, when the shell polymer is deformed at the film forming temperature (Tg of the shell polymer is equal to or lower than the film forming temperature), microvoids decrease. , 0.4 or less, particularly preferably 0.25 or less. When a monomer having a fluorine atom is used, the refractive index of the core-shell fine particles decreases as the content of the fluorine atom in the polymer increases. In order to sufficiently reduce the refractive index of the antireflection film for the purpose of the present invention,
Preferably, the polymer contains from 15% to 80% by weight of fluorine atoms, particularly preferably from 25% to 75% by weight.

The polymerizable fine particles of the present invention can be prepared as a polymer latex by a generally well-known emulsion polymerization method. For the emulsion polymerization method, Soichi Muroi:
Chemistry of Polymer Latex (Polymer Publishing Association) [1970]
It is described in detail in. In the emulsion polymerization method, for example, water or a mixed solvent of water and an organic solvent miscible with water (eg, methanol, ethanol, acetone, etc.) is used as a dispersion medium, and a monomer mixture of 5 to 40% by weight based on the dispersion medium is used. Using 0.05 to 5% by weight of a polymerization initiator and 0.1 to 20% by weight of a dispersant with respect to a monomer;
C., preferably 60 to 90.degree. C. for 3 to 8 hours with stirring. Conditions such as the dispersion medium, the concentration of the monomer, the amount of the initiator, the amount of the dispersant, the reaction temperature, and the time may be appropriately set in consideration of the average particle diameter of the target particles.

Examples of the initiator include inorganic peroxides such as potassium persulfate and ammonium persulfate; azonitrile compounds such as sodium salt of azobiscyanovaleric acid; and azoamidines such as 2,2'-azobis (2-methylpropionamide) hydrochloride. Compounds, cyclic azoamidine compounds such as 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] hydrochloride, 2,2'-azobis {2-
Methyl-N- [1,1'-bis (hydroxymethyl)-
Azoamide compounds such as [2-hydroxyethyl] propionamide}. Among them, potassium persulfate,
Ammonium persulfate is preferred. As the dispersant, any of an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant can be used, and an anionic surfactant is preferable.

When the polymerizable fine particles of the present invention have a core-shell structure, they can be prepared as a core-shell polymer latex by a seed emulsion polymerization method. The core-shell polymer latex can be easily obtained by a seed emulsion polymerization method in which a monomer for forming a shell is added or dropped at a time to an aqueous dispersion obtained by emulsion polymerization of a core latex polymer and emulsion polymerization is further performed. The core latex can be obtained by the above emulsion polymerization, or a commercially available product may be used. When adding a shell monomer in the presence of a core latex in seed emulsion polymerization, a dispersing agent may or may not be added, but the system is not destabilized by the shell monomer addition polymerization. As far as possible, an excess of the dispersant causes another particle to be generated, so it is preferable not to add the dispersant. It is also preferable to remove excess dispersant by dialysis in order to prevent generation of another particle. The polymerizable fine particles of the present invention can be obtained as an aqueous dispersion by the above-mentioned emulsion polymerization method or seed emulsion polymerization method, but can also be made into fine particle powder while maintaining the particle form. Such powdering methods include freeze-drying, coagulation using a strong acid or salt, filtration,
Alternatively, a known method such as coagulation by repeated freezing and thawing of a latex solution and a filtration method can be used.

The amount of voids introduced into the film by the polymerizable fine particles of the present invention is not particularly limited, but is preferably 3% by volume or more and 50% by volume or less from the viewpoint of introducing effective voids into the film. Is from 5% by volume to 35% by volume.

The polymerizable fine particles used in the present invention may be used by mixing arbitrary two or more kinds of particles in an arbitrary ratio in one antireflection film. Further, the polymerizable fine particles of the present invention and the fine particles outside the present invention may be used in combination. In this case, the polymer other than the present invention to be used in combination is not particularly limited, but may be particles obtained by ordinary emulsion polymerization, or may be an emulsion of a water-insoluble polymer obtained by separately prepared organic solvent-based solution polymerization.

The polymerizable binder used in the present invention is not particularly limited as long as it has at least one polymerizable group in one molecule which can be copolymerized with the polymerizable functional group of the polymerizable fine particles. Commercially available or synthetic polymerizable binders can be suitably used. As the polymerizable group, an epoxy group and a vinyl group are preferably used. Monofunctional monomers, polyfunctional monomers, polyfunctional oligomers, polyfunctional polymers, polyfunctional polymer latexes and the like having the above functional groups are preferably used, and more preferably polyfunctional oligomers.
Further, two or more kinds of polymerizable binders may be used as a mixture. Both water-soluble and oil-soluble polymerizable binders can be preferably used. Since the polymerizable fine particles of the present invention are usually used as an aqueous dispersion, when the polymerizable binder is oil-soluble, it is used after emulsification, or a method in which the polymerizable fine particles are dried and then redispersed in an organic solvent is used. Can be

[0026]

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[0027]

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[0028]

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The mixing ratio of the polymerizable fine particles and the polymerizable binder of the present invention is not particularly limited, but the polymerizable fine particles may be contained in an amount of 30% by weight to 95% by weight from the viewpoint of enhancing the film quality and introducing effective voids into the film. Is preferably 50% by weight to 95% by weight.
% By weight is particularly preferred.

When the polymerizable binder is a polyfunctional polymer latex, the Tg is preferably lower than the Tg of the polymer component forming the polymerizable fine particles of the present invention. As a result, the polymerizable binder latex is deformed at the time of film formation and serves as a binder between the polymerizable fine particles, and sufficient film strength can be expected. However, the polymerizable binder T
If g is very close to the Tg of the polymer component forming the polymerizable fine particles, the polymerizable fine particles are deformed and microvoids are reduced, so that the Tg of the polymerizable binder is 5 ° C. or more lower than the Tg of the polymerizable fine particle polymer. Preferably,
It is particularly preferable that the temperature is lower than 20 ° C. in consideration of the width of Tg and the fluctuation of the film forming temperature.

The photopolymerization initiator of the present invention is not particularly limited as long as it is a compound that generates a polymerization initiator species upon irradiation with light, and a commercially available or synthetic photopolymerization initiator can be suitably used. The photopolymerization initiator is described in detail in Polymer Society of Japan: Synthesis and Reaction of Polymer (1), pages 448 to 464 (Kyoritsu Shuppan). As a photoradical polymerization initiator, aromatic ketones, acetophenones, carbonyl compounds such as diketones, sulfur compounds such as disulfides, organic peroxides such as benzoyl peroxide, azo compounds such as azobisisobutyronitrile, Examples of the photocationic polymerization initiator include onium salts such as diaryliodonium salts, triarylsulfonium salts, and aromatic diazonium salts. Among them, acetophenones are used as the photoradical polymerization initiator, and diaryl is used as the photocationic polymerization initiator. An iodonium salt is preferably used. A sensitizing dye can also be preferably used in combination with the above photopolymerization initiator. The addition amount of the photopolymerization initiator is preferably from 0.1 to 10% by weight, more preferably from 0.5 to 7% by weight, based on the weight of the solid content (particles and binder) in the layer.

As the substrate on which the antireflection film of the present invention is formed, various plastic films can be used, and cellulose derivatives (for example, triacetyl- (TAC), diacetyl-, propionyl-, butanoyl-, acetylpropionyl-acetate) can be used. , Nitro-, etc.), polyamides,
Polycarbonate, polyester described in JP-B-48-40414 (especially polyethylene terephthalate, poly-1,4-cyclohexane dimethylene terephthalate,
Polyethylene 1,2-diphenoxyethane-4,4-dicarboxylate, polybutylene terephthalate, polyethylene naphthalate, etc.), polystyrene, polypropylene, polyethylene, polymethylpentene, polysulfone, polyethersulfone, polyarylate, polyetherimide Various transparent resins such as polymethyl methacrylate and the like are preferably used.

When used as a multilayer film, the following materials can be used as the material of the high refractive index layer provided below the low refractive index layer of the present invention.

As the organic material, a film-forming substance having a relatively high refractive index, for example, polystyrene, a polystyrene copolymer, polycarbonate, an aromatic ring other than polystyrene,
Various polymer compositions having a heterocyclic ring, an alicyclic cyclic group, or a halogen group other than fluorine, various thermosetting resin-forming compositions using a melamine resin, a phenol resin, or an epoxy resin as a curing agent, an alicyclic ring A urethane-forming composition comprising a formula or an aromatic isocyanate and / or a polyol thereof and a polyol, and a composition containing various modified resins or prepolymers capable of radical curing by introducing a double bond into the above compound. It is preferably used. In addition, as the organic material in which the inorganic fine particles are dispersed, a material having a lower refractive index than that in the case where the organic material is used alone is generally used because the inorganic fine particles have a high refractive index. In addition to the organic materials described above, acrylic-based vinyl copolymers, polyester (including alkyd) -based polymers, cellulose-based polymers, urethane-based polymers, and various curing agents for curing these, Various organic materials having transparency and stably dispersing inorganic fine particles, such as a composition having a curable functional group, can be used. Further, an organic-substituted silicon-based compound can be included therein.

These silicon compounds have the general formula R ¹ _a R ² _b SiX _{4- (a + b)} (where R ¹ and R ² are an alkyl group, an alkenyl group,
Allyl group, or halogen group, epoxy group, amino group,
Hydrocarbon groups having a mercapto group, a methacryloxy group or a cyano group. X is a hydrolyzable substituent selected from alkoxyl, alkoxyalkoxyl, halogen and acyloxy groups. a and b are each an integer of 0 to 2, and a + b is 1 or 2. ) Or a hydrolysis product thereof.

As the inorganic compound dispersed therein, oxides of metal elements such as aluminum, titanium, zirconium and antimony are preferably used. These may be provided in finely divided form as a powder or as a colloidal dispersion in water and / or other solvents. These are mixed and dispersed in the above organic material or organosilicon compound.

Inorganic materials which are film-forming and can be dispersed in a solvent or are themselves liquid include alkoxides of various elements, salts of organic acids, and coordination compounds bonded to coordination compounds. Examples include titanium tetraethoxide, titanium tetra-i-propoxide, titanium tetra-n-propoxide, titanium tetra-n-butoxide,
Titanium tetra-sec-butoxide, titanium tetra-tert
-Butoxide, aluminum triethoxide, aluminum tri-i-propoxide, aluminum tributoxide, antimony triethoxide, antimony tributoxide, zirconium tetraethoxide, zirconium tetra-i-propoxide, zirconium tetra-n-
Propoxide, zirconium tetra-n-butoxide,
Zirconium tetra-sec-butoxide, metal alcoholate compounds such as zirconium tetra-tert-butoxide, further di-isopropoxytitanium bisacetylacetonate, di-butoxytitanium bisacetylacetonate, di-ethoxytitanium bisacetylacetonate, Bisacetylacetone zirconium, aluminum acetylacetonate, aluminum di-n-
Chelate compounds such as butoxide monoethyl acetoacetate, aluminum di-i-propoxide monomethyl acetoacetate, and tri-n-butoxide zirconium monoethyl acetoacetate, and further active inorganic polymers containing zirconium ammonium carbonate or zirconium as a main component Can be given. In addition to those described above, various alkyl silicates or hydrolysates thereof, and finely divided silica, particularly silica gel dispersed in a colloidal form, are used as those which have a relatively low refractive index but can be used in combination with the above compounds.

Each of the layers forming the antireflection film of the present invention may be formed by a generally known method, for example, a dip coating method.
Coating by air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, or extrusion coating using a hopper described in U.S. Pat. No. 2,681,294. Can be. Also, if necessary, U.S. Pat. Nos. 2,761,791, 3,508,947, 2,9
No. 41,898 and 3,526,528, two or more layers can be simultaneously coated by the method described in Yuji Harazaki, “Coating Engineering”, page 253 (published by Asakura Shoten in 1973). .

The low-refractive-index antireflection layer of the present invention may be provided with a hard coat layer, a moisture-proof, antistatic layer and the like as an intermediate layer. As the hard coat layer, silica-based compounds can be used in addition to acrylic-based, urethane-based, and epoxy-based polymers.

The surface of the low-refractive-index antireflection film layer of the present invention can be formed with an organic or inorganic compound to provide an anti-glare effect of scattering external light to prevent reflection of a scenery or the like. However, it is preferable that the haze value of the antireflection film is 3 to 30%. The antireflection film is used alone or in combination with the anti-glare effect in image display devices such as a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), and a cathode ray tube display (CRT). However, visibility can be significantly improved by preventing reflection of external light.

[0041]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. (Synthesis of Polymerizable Fine Particles) 1) Synthesis of Epoxy Group-Containing Fine Particles (FP1) A solution prepared by dissolving 30 g of sodium dodecyl sulfate in 2.7 liters of distilled water was placed in a 5-liter three-necked flask equipped with a cooling tube and a stirrer. Hexafluoroisopropyl methacrylate 480 g, divinylbenzene 60
g and glycidyl methacrylate (60 g) were added, and the mixture was stirred at a speed of 200 rpm under a nitrogen stream. The reaction vessel was heated to 75 ° C., and an initiator solution obtained by dissolving 12 g of potassium persulfate in 150 ml of water was added, followed by polymerization for 5 hours. The reaction solution was cooled to room temperature, dialyzed using a cellulose membrane having a molecular weight cut off of 10,000 to remove excess surfactants and inorganic salts, and then filtered to remove insolubles to obtain 4500 g of a milky white dispersion. I got This dispersion has a non-volatile content of 13.
It was a fine latex liquid containing 3% by weight and having an average particle diameter of 30 nm. The particle size is measured by Coulter's particle analyzer N4
Was evaluated by the dynamic light scattering method.

(Synthesis of Polymerizable Core-Shell Fine Particles) 2-1) Synthesis of Core Fine Particles A solution prepared by dissolving 30 g of sodium dodecyl sulfate in 2.7 liters of distilled water was placed in a 5-liter three-necked flask equipped with a cooling tube and a stirrer. Next, 480 g of hexafluoroisopropyl methacrylate and divinylbenzene 12
0 g of the mixed solution was added, and the mixture was stirred at a speed of 200 rpm under a nitrogen stream. The reaction vessel was heated to 75 ° C., and an initiator solution obtained by dissolving 12 g of potassium persulfate in 150 ml of water was added, followed by polymerization for 5 hours. The reaction solution was cooled to room temperature, dialyzed using a cellulose membrane having a molecular weight cut-off of 10,000 to remove excess surfactants and inorganic salts, and then filtered to remove insolubles, thereby obtaining 4510 g of a milky white dispersion. I got This dispersion had an average particle diameter of 20 n containing 13.2% by weight of nonvolatile components.
m latex liquid.

2-2) Synthesis of Epoxy Group-Containing Core-Shell Microparticles (FP8) 75.7 g of the core latex synthesized in 2-1) above in a 100 ml three-necked flask equipped with a cooling tube and a stirrer.
(Solid content: 13.2% by weight, solid content: 10 g) and an initiator solution obtained by dissolving 0.022 g of potassium persulfate in 10 ml of water, and then adding 0.5 g of n-butyl methacrylate.
A mixed solution of 5 g of glycidyl methacrylate and 0.55 g of glycidyl methacrylate was added, and the mixture was stirred at 75 ° C. for 4 hours under a nitrogen stream at a speed of 200 rpm to perform polymerization. The reaction solution was cooled to room temperature, and insoluble components were removed by filtration to obtain 90.3 g of a white dispersion.
I got This dispersion was a fine latex liquid containing 11.6% by weight of nonvolatile components and having an average particle diameter of 25 nm.

The other fine particles used in the present invention were synthesized by the same method as that described above or a method similar thereto. The reactive fine particles of the present invention (FP1 to FP1) synthesized by these methods
0) is shown below. In the formula, the monomer content is expressed in% by weight. For the core-shell fine particles (FP8 to FP10), the content of the monomer in the core polymer (% by weight) and the content of the monomer in the shell polymer (% by weight) are represented in the formulas, respectively. The numbers in parentheses indicate the core-shell weight ratio.

[0045]

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[0046]

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Further, comparative fine particles were also synthesized by the same method as that described above or a method similar thereto. Fine particles for comparison (NP
1 to NP3) are shown below.

[0048]

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The polymerizable fine particles of the present invention (FP1 to FP
Table 1 summarizes the particle size and fluorine content of 10) and the comparative fine particles (NP1 to NP3).

[0050]

[Table 1]

Example 1 (Coating of antireflection layer and evaluation of performance) Using the polymerizable fine particles shown in Table 1, coating solutions (E1 to E14) having the compositions shown in Table 2 were prepared. However, when the polymerizable binders (B1 to B3) were used together, the following additives were added. B1 and B3: Photocationic polymerization initiator (diphenyliodonium hexafluorophosphate) 5
% By weight vs. binder. B2: 5% by weight of a photo-radical polymerization initiator (trade name: Irgacure 907, manufactured by Ciba Geigy) to binder, photosensitizer (trade name: Kayacure DE)
TX, manufactured by Nippon Kayaku Co., Ltd.) 1.3% by weight to binder, emulsifier (sodium dodecylbenzenesulfonate) 5% by weight
Binder, 300% by weight of ethyl acetate vs. binder.
A coating solution shown in Table 2 was prepared using triacetyl cellulose (hereinafter referred to as TA).
C) on the film using a spin coater,
After drying at 100 ° C. for 10 minutes, a low refractive index layer having a thickness of 100 nm was formed. Further, ultraviolet irradiation was performed for 1 minute using a high-pressure mercury lamp of 12 W / cm. The obtained film (X1 to X1
4) About refractive index, luminous reflectance (light wavelength 400nm ~
(Average reflectance value at 800 nm), porosity measurement and film surface strength measurement. The porosity of the low refractive index layer was calculated by measuring the refractive index of the layer and assuming that the difference from the calculated value of the refractive index of the layer obtained from the composition of the layer constituting components used was caused by air. The film surface strength was rubbed with a tissue and an eraser, respectively, and visually observed. ○: Those which were not damaged by any of the methods, △: Those which were not damaged by the tissue but were damaged by the eraser,
Those that were damaged by any of the methods were evaluated as x. The results are shown in Table 3.

[0052]

[Table 2]

[0053]

[Table 3]

The same procedure as in Example 1 was repeated except that the fine particles of the present invention used in Example 1 were replaced with particles (NP1 to NP3) outside the present invention as shown in Table 2, and the comparative sample solution coating solution (F1 to F3) was used. F6) was prepared and formed into a film under the same conditions to obtain comparative samples (Y1 to Y6). The same measurement as in Example 1 was performed on the obtained film. The results are shown in Table 3.

Example 2 (Preparation of multilayer antireflection film) (1) Coating of first layer (hard coat layer) 5% by weight of dipentaerythritol hexaacrylate on a TAC film having a thickness of 90 μm and photopolymerization initiation Agent (trade name: Irgacure 907, manufactured by Ciba Geigy)
0.5% by weight, photosensitizer (trade name: Kaya Cure DET)
X, manufactured by Nippon Kayaku Co.) A toluene solution containing 0.2% by weight was applied to a thickness of 8 μm using a wire bar, dried, heated to 100 ° C., and a high-pressure mercury lamp of 12 W / cm was used. For 1 minute to crosslink. Then, it was allowed to cool to room temperature.

(2) Coating of Second Layer (High Refractive Index Layer) Separately synthesized poly (n-butyl methacrylate-co-methacrylic acid) latex (copolymer composition weight ratio: 80: 2)
0, average particle diameter 63 nm, solid content concentration 12.5% by weight)
100 g and tin oxide fine particles (obtained from Ishihara Sangyo Co., Ltd.) 25 g were mixed, and dipentaerythritol hexaacrylate 6 g, a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Geigy) 0.5 g, light Sensitizer (trade name: Kaya Cure DETX, manufactured by Nippon Kayaku)
An emulsion liquid obtained by emulsifying and dispersing 0.2 g of ethyl acetate and 20 g of ethyl acetate in 100 g of water using 1 g of sodium dodecylbenzenesulfonate was mixed and stirred to prepare a coating solution. This solution was applied on the first layer prepared above to a thickness of 0.16 μm using a wire bar, dried, heated to 100 ° C., and irradiated with ultraviolet light for 1 minute using a 12 W / cm high-pressure mercury lamp. Irradiation was carried out to crosslink, and then allowed to cool to room temperature. A high refractive index layer having a refractive index of 1.55 was obtained by the above method.

(3) Preparation of Third Layer (Low Refractive Index Layer) The coating liquids (E1 to E14) described in Table 2 of Example 1 were applied on the second layer prepared above using a wire bar. It was applied to a thickness of 0.10 μm and dried at 100 ° C. for 10 minutes. Further, ultraviolet irradiation was performed for 1 minute using a high-pressure mercury lamp of 12 W / cm. Thereafter, the mixture was allowed to cool to room temperature to obtain multilayer antireflection films ARF1 to ARF14. Table 4 shows the surface performance of these films. As comparative examples, the coating films (F1 to F6) shown in Table 2 of Example 1 were used for the third layer to obtain comparative films CF1 to CF6. These surface performances are also shown in Table 4.

[0058]

[Table 4]

As is clear from this example, the antireflection film of the present invention not only has excellent antireflection performance having a very low reflectance and a wide wavelength range, but also has a sufficiently strong film strength. You can see that it is.

Example 3 (Preparation of a display device provided with an antireflection film) The antireflection film ARF1 prepared in Example 2 was attached to a liquid crystal display surface of a personal computer PC9821Ns / 340W obtained from NEC Corporation. A display device sample was prepared, and the degree of scenery reflection due to surface reflection was visually evaluated. Similarly, the antireflection films used in the above method were the films ARF4, ARF11, ARF13, CF prepared in Example 2.
1. A display device sample was prepared using CF2. Antireflection films ARF1, ARF4, ARF1 of the present invention
1. The display device provided with the ARF 13 showed comfortable visibility with almost no surrounding scenery reflected, whereas the display device provided with the comparative film CF1 showed many surrounding scenery reflections, resulting in poor visibility. Was something. Further, the display device provided with the comparative film CF2 had excellent visibility but had low surface strength and was not practically usable.

Example 4 (Anti-glare-treated antireflection film) Example 2 was carried out using Sumicaran AG2 (manufactured by Sumitomo Chemical Co., Ltd., haze value: 9%) as a polarizing plate having a surface subjected to anti-glare treatment. Was formed (Haze value: 9%). When the polarizing plate subjected to the anti-reflection treatment was incorporated into the surface side of a liquid crystal display (LCD), reflection of external light and reflection of scenery were greatly reduced, and a display with high display quality could be obtained. .

[0062]

According to the present invention, by applying a film using polymerizable fine particles, the adhesion between particles can be improved without impairing the voids. As a result, very good optical properties are exhibited as an anti-reflection film, and a low-cost, large-area anti-reflection film having excellent film properties such as film strength and scratch resistance can be provided in a form having suitability for production. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an antireflection film formed of a layer composed of fine particles having a polymerizable group of the present invention.

FIG. 2 is a cross-sectional view of an antireflection film including a layer made of fine particles having a polymerizable group of the present invention and a layer having a refractive index higher than that of a substrate.

[Explanation of symbols]

 1: Low refractive index layer 2: High refractive index layer 3: Base material

Claims (6)

[Claims] 1. A polymer fine particle having a polymerizable functional group having an average particle diameter of 200 nm or less, a binder having at least one polymerizable functional group copolymerizable with the polymerizable functional group in one molecule, and polymerization. An antireflection film, comprising a layer containing an initiator, wherein the layer is a low refractive index layer cured by ultraviolet irradiation. 2. The antireflection film according to claim 1, wherein the low refractive index layer contains at least 3% by volume or more of voids. 3. The fine particle according to claim 1, wherein the polymerizable functional group is an epoxy group or a vinyl group.
2. The antireflection film according to 1. 4. The antireflection film according to claim 1, wherein said fine particles have a core-shell structure. 5. The haze value of the antireflection film is 3 to 3
5. The antireflection film according to claim 1, wherein the content is 0%. 6. A polymer fine particle having a polymerizable functional group having an average particle size of 200 nm or less, a binder having at least one polymerizable functional group copolymerizable with the polymerizable functional group in one molecule, and polymerization. A display device comprising a layer containing an initiator, and an antireflection film, which is a low-refractive-index layer cured by irradiation with ultraviolet light, disposed on the layer.