JP2000241603A - Antireflection film, and display device with antireflection film arranged thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection coating low in reflectance in a wide range of wavelengths, high in coating strength, and excellent in manufacturing suitability. SOLUTION: This antireflection film has a low refractive index layer provided by applying to a base material a composition consisting of a homogeneous mixture of a methacrylate polymer particulate which contains not less than 70 wt.% of repeating units provided by polymerizing a methacrylic acid ester monomer and which can be decomposed by an electron beam, and an acrylate polymer particulate which contains not less than 70 wt.% of repeating units provided by polymerizing an acrylic acid ester or α-fluoroacrylic acid ester monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display (L).
The present invention relates to an antireflection film effective for lowering the reflectance of the surface of an image display device such as a CD) and an image display device having the antireflection film. In particular, the present invention relates to an antireflection film realizing mass productivity and high film strength, and a display device provided with the antireflection 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, resistance to reflected light (visibility assurance), durability (scratch resistance, stain resistance) And heat resistance) are required to be improved. 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 anti-reflection film is provided on the outermost surface in order to exhibit its function, many high quality issues are inevitably concentrated on the performance of the anti-reflection film from the viewpoint of toughness. For example, reduction of reflectance to the limit, difficulty of scratching, prevention of adhesion of fingerprints and fats and oils, easy removal, maintenance of various performances in a high temperature environment such as under the sun or in a car interior.

Conventionally, as an antireflection film of a wide wavelength range / low reflectance having a performance capable of covering the entire wavelength range of visible light, a transparent thin film of a metal oxide such as MgF ₂ or silicon dioxide is formed by a method such as vapor deposition. Stacked multilayer films have been used. The production of a multilayer film by vapor deposition or the like requires a number of operations to control the film thickness with high precision, is very expensive, and it is very difficult to obtain a film with a large area. It was poor in suitability for mass production. On the other hand, although an antireflection film by a coating method has been developed, there is a problem how to lower the refractive index of the uppermost layer (air interface side) of the film and enhance the physical characteristics of the film. Conventionally, development of a low refractive index polymer containing a fluorine atom has been earnestly advanced.
Further, attempts have been made to provide minute air holes (microvoids) in the film to lower the refractive index of the film. For example, JP-A-9
JP-A-222502 describes a method of mixing two types of latex having different Tg (glass transition point) to fuse a latex having a low Tg to form a film having voids between particles. Japanese Patent Application Laid-Open No. Hei 6-3501 describes that an optical material having a lower refractive index than that of a matrix material can be obtained by dispersing minute pores. It is described that a substance generating a gas is contained in a matrix. Although these methods are relatively simple methods, they have problems that it is difficult to control the size and distribution of the voids and it is difficult to obtain a film having uniform optical properties.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an antireflection film having a low reflectance (reflectance of 1% or less) over a wide range of wavelengths and having excellent film strength and durability. It is to provide in a cost-effective and large-scale and large-area manufacturing suitable manner. Another object of the present invention is to provide a display device provided with the antireflection film.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a methacrylate polymer fine particle containing at least 70% by weight of a repeating unit obtained by polymerizing a methacrylate monomer and decomposable by electron beam irradiation; Alternatively, a low-refractive-index layer obtained by applying a composition obtained by uniformly coating a composition obtained by uniformly mixing acrylate polymer fine particles containing at least 70% by weight of a repeating unit obtained by polymerizing an α-fluoroacrylic acid ester monomer on a support. This has been attained by an antireflection film characterized by having:

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the antireflection film of the present invention will be described below, but the present invention is not limited to these. (1) A methacrylate polymer fine particle containing 70% by weight or more of a repeating unit obtained by polymerizing a methacrylate monomer and decomposable by electron beam irradiation is polymerized with an acrylate or α-fluoroacrylate monomer. An antireflection film comprising a low refractive index layer obtained by applying a composition obtained by uniformly mixing a resulting acrylate polymer fine particle containing at least 70% by weight of a repeating unit on a support. (2) The antireflection film according to item 1, wherein the methacrylate polymer fine particles have an average particle diameter of 200 nm or less. (3) The antireflection film according to item 1 or 2, wherein the acrylate polymer fine particles have an average particle diameter of 200 nm or less. (4) The antireflection film according to any one of Items 1 to 3, wherein the acrylate polymer fine particles contain a fluorine atom. (5) The amount of the acrylate polymer fine particles in the composition is
Item 5. The antireflection film according to any one of Items 1 to 4, wherein the content is 50 to 90% by weight based on the total solid weight. (6) The antireflection film according to any one of Items 1 to 5, wherein the amount of the methacrylate polymer fine particles in the composition is 10 to 50% by weight based on the total solid weight. (7) The antireflection film, wherein the antireflection film comprises the low refractive index layer according to any one of Items 1 to 6 and a high refractive index layer having a refractive index of 1.7 or more adjacent thereto. film. (8) A medium refractive index layer having a middle refractive index layer having a refractive index of 1.7 or less between the support and the high refractive index layer.
8. The antireflection film according to any one of items 1 to 7. (9) 70% by weight of a methacrylate polymer fine particle containing at least 70% by weight of a repeating unit obtained by polymerizing a methacrylate monomer and a repeating unit obtained by polymerizing an acrylate or α-fluoroacrylate monomer; % Of an acrylate polymer fine particle containing at least 1% by weight of an antireflection film having a low refractive index layer, wherein the composition is coated on a support, dried, and then irradiated with an electron beam to form voids. Production method. (10) An image display device comprising the antireflection film according to any one of Items 1 to 9 on a front surface of the image display device.

The components of the present invention will be described in detail. (a) Methacrylate polymer fine particles (hereinafter referred to as “methacrylate particles”) The methacrylate polymer fine particles used in the present invention contain a methacrylate ester monomer as a main constituent monomer.
There is no particular limitation as long as it is a methacrylate fine particle polymer having 0% by weight or more. In the composition of the present invention, the composition is cleaved radically by irradiation with an electron beam, and functions to form fine voids (hereinafter referred to as voids) in the low refractive index layer. As these methacrylic acid ester monomers, those described below can be preferably used. General formula (I)

[0008]

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In the formula, R ₁ is an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms (eg, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, hexyl) Group, cyclohexyl group,
n-octyl group, n-decyl group, n-dodecyl group, n-
Octadecyl group, 2-hydroxyethyl group, 2-chloroethyl group, 2-ethylhexyl group, ω-hydroxypolyoxyethylene group, fluoroalkyl group represented by the following formula (II) or (III):

[0010]

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(Wherein, X ₁ represents a hydrogen atom or a fluorine atom; p represents an integer of 1 to 2; n represents an integer of 1 to 10) General formula (III)

[0012]

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(Where X is_TwoAnd X_ThreeAre each independently water
Represents an element atom or a fluorine atom. m ₁, And m_TwoIs it
Each independently represents an integer of 1 to 10. ), Etc.)
Is an unsubstituted or substituted ant having 6 to 10 carbon atoms
Phenyl group, p-toluyl group, p-methoyl group
Xyphenyl group, p-chlorophenyl group, α-naphthyl
Group, β-naphthyl group, p-nonylphenyl group, etc.)
I forgot. Preferably, C 1 to C 10 alky as defined above.
A kill group and an aryl group as defined above having 6 to 10 carbon atoms
And particularly preferably one having the above definition having 1 to 6 carbon atoms.
An alkyl group and a phenyl group. Of these monomers
Any two or more kinds may be used in combination.

In the methacrylate particles of the present invention, in addition to the above-mentioned methacrylate monomer, a copolymer monomer may be used in combination as long as the void-forming ability of the particles is not impaired. There are no particular restrictions on the monomer units that can be used, and for example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylates (methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, etc.) ), Α-chloroacrylic esters, styrene derivatives (styrene, divinylbenzene, vinyltoluene, etc.), vinyl ethers (methyl vinyl ether, etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tertbutylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides, acrylonitrile derivatives and the like. The preferred copolymerization amount of these comonomers varies depending on the type of the monomer used, but is preferably about 0 to 20% by weight, particularly preferably 0 to 10% by weight based on the total weight of the methacrylate particles.

The particle size of the 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, the thickness is preferably 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.

The specific method of emulsion polymerization for obtaining a polymer latex is described in detail in a book such as "Experimental Method for Polymer Science" edited by The Society of Polymer Science, Tokyo Kagaku Dojin (1981). And these equivalent methods can be used.

Preferred specific examples of the methacrylate particles used in the present invention are shown below, but the present invention is not limited to these. Examples of methacrylate particles MP-1 Polymethyl methacrylate average particle diameter 47 nm MP-2 Polybutyl methacrylate average particle diameter 102 nm MP-3 Polytetrafluoroisopropyl methacrylate average particle diameter 34 nm MP-4 Poly (methyl methacrylate-co- MP-5 Poly (methyl methacrylate-co-methyacrylate-2-hydroxyethyl) (trifluoromethyl methacrylate) (copolymerization ratio: 95/5% by weight) Average particle size: 23 nm Particle size 61nm MP-6 poly (butyl methacrylate-co-methacrylic acid) (copolymerization ratio 93/7 wt%) Average particle size 53nm MP-7 poly (ethyl methacrylate-co-α-ethyl chloroacrylate (co Polymerization ratio 85/15% by weight) Average particle size 50nm MP-8 Poly (methyl methacrylate-co-methacrylic acid-n-butyl-co-methacrylic acid) (copolymerization ratio 50/40/10% by weight) Average particle size 74nm MP-9 poly ( Methyl methacrylate-co-styrene-co-2-ethylhexyl methacrylate (copolymerization ratio 45/15/40% by weight) Average particle diameter 42 nm MP-10 poly (n-butyl methacrylate-co-methacrylonitrile) ( (Copolymerization ratio 95/5% by weight) Average particle size 34nm

(B) Acrylate polymer fine particles (hereinafter referred to as acrylate particles) The acrylate particles used in the present invention are not particularly limited as long as they are fine particle polymers containing 70% by weight or more of an acrylate monomer as a main constituent monomer. There is no. The composition of the present invention functions to give a crosslinked binder structure of the low refractive index layer by generating and recombining radicals by irradiation with an electron beam. As these acrylic acid ester monomers, those described below can be preferably used. General formula (IV)

[0019]

Embedded image

Where R_TwoRepresents a hydrogen atom or a fluorine atom
I forgot. R_ThreeIs the R of the above general formula (I) ₁Same as the group defined in
Righteousness.

In the acrylate particles of the present invention, in addition to the above-mentioned acrylate ester monomers, a copolymerization monomer may be used in combination as long as the strength of the crosslinked structure formed by electron beam irradiation of the particles is not impaired. . There is no particular limitation on the monomer units that can be used in combination, for example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc.), Styrene derivatives (styrene, vinyl toluene, α
-Methylstyrene, etc.), vinyliethers (eg, methyl vinyl ether), vinyl esters (vinyl acetate,
Vinyl propionate, etc.), acrylamides (Nt
tert-butylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides, acrylonitrile derivatives and the like.

In order to supplement the strength of the crosslinked structure formed by the acrylate particles, the acrylate particles preferably contain a polyfunctional monomer.

The polyfunctional monomer is not particularly limited and may be suitably used as long as it is commercially available or has a plurality of polymerizable unsaturated groups in one molecule of the synthesis. 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,
For example, olefins (eg, butadiene, pentadiene, divinylcyclohexane, etc.), acrylates (eg, ethylene glycol diacrylate, 1,4-cyclohexane diacrylate, dipentaerythritol hexaacrylate), styrene derivatives (1,4-
Examples thereof include divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, and the like, vinyl sulfones (such as divinyl sulfone), acrylamides (such as methylenebisacrylamide), and methacrylamides.

The content of the comonomer in the acrylate fine particles of the present invention varies depending on the type and combination of the comonomers used in combination, but is preferably 20 mol% or less of the total monomer units, particularly preferably 10 mol% or less of the total monomer units.
Mol% or less. When the refractive index of the acrylate fine particles described above is a monomer having a fluorine atom,
It decreases as the content of fluorine atoms in the polymer increases. In order to sufficiently lower the refractive index of the antireflection film for the purpose of the present invention, the polymer preferably contains 35% by weight to 80% by weight of fluorine atoms, particularly preferably 45% by weight.
% To 75% by weight.

Preferred examples of the acrylate particles used in the present invention will be shown below, but the present invention is not limited to these. AP-1 Methyl polyacrylate average particle size 35nm AP-2 Polytrifluoroacrylate trifluoropropyl average particle size 26nm AP-3 Polyheptadecafluorodecyl polyacrylate average particle size 55nm AP-4 Poly (heptadecafluorodecyl acrylate) (Co-methyl acrylate) (copolymerization ratio 80/20 wt%) Average particle size 44 nm AP-5 poly (hexafluoroisopropyl acrylate-co-α-methyl fluoroacrylate) (copolymerization ratio 50/50 wt%) Average particle size 47 nm AP-6 poly (hexafluoroisopropyl acrylate-co-hydroxyethyl acrylate) (copolymerization ratio 75/25% by weight) Average particle size 35 nm AP-7 poly (heptadecafluorodecyl acrylate) (Co-acrylic acid) (copolymerization ratio 95/5% by weight) Average particle size 61nm AP-8 Poly (hexafluoroisopropyl acrylate-co-ethylene glycol diacrylate) (copolymerization) 95/5 weight%) Average particle size 46nm AP-9 Poly (hexafluoroisopropyl acrylate-co-styrene-co-2-ethylhexyl acrylate) (copolymerization ratio 45/10/45 weight%) Average particle size 81nm AP-10 Poly (heptadecafluorodecyl acrylate-co-acrylonitrile (copolymerization ratio 98/2% by weight) Average particle size 56nm

The acrylate polymer fine particles used in the present invention may be used by mixing two or more kinds of arbitrary particles in an arbitrary ratio in one antireflection film. The Tg of the acrylate polymer fine particles is preferably lower than the Tg of the methacrylate polymer fine particles of the present invention. As a result, the acrylate particles serve as a binder that deforms during film formation to form a continuous phase, and sufficient film strength can be expected. The Tg of the acrylate polymer fine particles is preferably lower by 5 ° C. or more than the Tg of the methacrylate polymer fine particles of the present invention, and particularly preferably 20 ° C. or more in consideration of the Tg width and the fluctuation of the film forming temperature.

The above components (a) and (b) are essential constituents of the composition of the present invention, but various compounds other than those described above can be added to the composition of the present invention as required. . The following is a description of the main materials for hei.

(C) Solvent The solvent uniformly mixes the components (a) and (b) in the composition, adjusts the solid content of the composition of the present invention, and enables the composition to be applied to various coating methods. It improves the dispersion stability and storage stability of the composition. These solvents are not particularly limited as long as they can achieve the above objects. Preferred examples of these solvents include, for example, water, alcohols, aromatic hydrocarbons, ethers, ketones,
Esters and the like are preferred. Particularly, water and alcohols or a mixed solvent thereof are preferably used.

Among them, the alcohols include, for example, monohydric alcohols and dihydric alcohols. Among them, the monohydric alcohol is preferably a saturated aliphatic alcohol having 1 to 8 carbon atoms. Specific examples of these alcohols include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, and ethylene glycol. Monobutyl ether and ethylene glycol monoethyl ether acetate can be exemplified.

(D) Filler It is also possible to add colloidal inorganic fine particles, for example, colloidal silica or colloidal magnesium fluoride, to the composition of the present invention for the purpose of improving the hardness of the resulting coating film. These colloidal inorganic fine particles are aqueous colloids,
An organic solvent-dispersed colloid such as methanol or isopropyl alcohol is preferably used.

The composition of the present invention contains the above-mentioned colloidal inorganic material in order to exhibit various properties such as coloring of the resulting coating film, imparting irregularities, preventing ultraviolet light transmission to the base, imparting corrosion resistance, and heat resistance. It is also possible to add and disperse a filler in addition to the fine particles. As the filler, for example, an organic pigment,
Examples include water-insoluble pigments such as inorganic pigments, and particulate, fibrous or flaky metals and alloys other than pigments, and oxides, hydroxides, carbides, nitrides, and sulfides thereof. Specific examples of the filler include particles,
Fibrous or scaly iron, copper, aluminum, nickel, silver, zinc, ferrite, carbon black, stainless steel, silicon dioxide, titanium oxide, aluminum oxide, chromium oxide, manganese oxide, iron oxide, zirconium oxide, cobalt oxide, Synthetic mullite, aluminum hydroxide, iron hydroxide, silicon carbide, silicon nitride, boron nitride,
Clay, diatomaceous earth, slaked lime, gypsum, talc, barium carbonate, calcium carbonate, magnesium carbonate, barium sulfate, bentonite, mica, zinc green, chrome green, cobalt green, viridian, guinea green, cobalt chrome green, shale green, green top , Manganese green, pigment green, ultramarine,
Navy blue, Pigment green, Rock ultramarine, Cobalt blue, Cerulean blue, Copper borate, Molybdenum blue, Copper sulfide, Cobalt purple, Mars purple, Manganese purple, Pigment violet, Lead oxide, Calcium plumbate, Zinc yellow, Lead sulfide, Chromium Yellow, loess, cadmium yellow, strontium yellow, titanium yellow, litharge, pigment yellow, cuprous oxide, cadmium red, selenium red, chrome vermillion, red iron, zinc white, antimony white, basic lead sulfate, titanium white, lithopone, Lead silicate, zircon oxide, tungsten white, lead zinc white, bunchison white, lead phthalate, manganese white, lead sulfate, graphite, bone black, diamond black,
Examples include thermatomic black, vegetable black, potassium titanate whisker, and molybdenum disulfide.

The average particle size or average length of these fillers is usually 5 to 200 nm, preferably 10 to 100 nm. When the filler is used, the proportion in the composition is as follows:
10 to 3 with respect to 100 parts by weight of the total solid content of the component (d).
It is about 0 parts by weight.

(E) Other additives In the composition of the present invention, additives such as various surfactants, silane coupling agents, titanium coupling agents, dyes, dispersants, thickeners and leveling agents are added. You can also.

The composition of the present invention is applied to a transparent film or a high or medium refractive index layer by a coating method such as curtain flow coating, dip coating, spin coating, roll coating, etc., and dried at room temperature, or 200
By heating at a temperature of about 1 ° C. for about 1 minute to 100 hours, it is coated on the support.

In the case of simultaneous multi-layer coating, the discharge flow rate is adjusted so that each of the lower layer coating liquid and the upper layer coating liquid has a required coating amount on a slide greaser having a multistage discharge port, and the formed multilayer flow is Is preferably applied to the support continuously and dried (simultaneous layering method).

The purpose of the electron beam irradiation, which constitutes a constituent feature of the present invention, is to simultaneously cause a cross-linking reaction of acrylate particles and a decomposition reaction of methacrylate particles, and as a result, a cross-linked structure and voids are simultaneously formed in a layer. The irradiation dose is not particularly limited as long as the above purpose can be achieved. Preferably the intensity of from 30 mJ / cm ² no 500 mJ / cm ^2,
Particularly preferably, it is 50 mJ / cm ² to 400 mJ / cm ² . The electron beam irradiation temperature is preferably 20 ° C to 200 ° C.
° C, particularly preferably 50 ° C to 120 ° C.

In the antireflection film of the present invention, the low refractive index layer (1) formed by coating the composition by the above method is different from the high refractive index layer (2) having a higher refractive index. It is preferable that it is formed on the upper surface and is composed of two or more layers. The refractive index of the low refractive index layer is preferably 1.45 or less, particularly 1.4.
0 or less is preferable. The refractive index of the high refractive index layer is preferably 1.7 or more, and particularly preferably 1.75 or more. Further, it is preferable that these layers are provided on a support, preferably a transparent film.

In the antireflection film of the present invention, the low-refractive-index layer (1) formed by applying the composition by the above-mentioned method is different from the high-refractive-index layer (2) having a higher refractive index. ), Adjacent to the high-refractive-index layer (2), opposite the low-refractive-index layer (1), to a middle-refractive-index layer (3), and further to a layer (4) (such as a support undercoat). 4. A high refractive index layer is formed on a middle refractive index layer having a refractive index intermediate between the refractive index of the high refractive index layer and that of the high refractive index layer.
It is particularly preferred that it is composed of layers. The refractive index of the high refractive index layer adjacent to the low refractive index layer is preferably 1.7 or more, and particularly preferably 1.75 or more. Further, it is preferable that these layers are provided on a support, preferably a transparent film.

The thickness of each layer is 50 to 2 for layer (1).
00 nm, layer (2) 50-200 nm, layer (3) 50-20
0 nm, the layer (4) preferably has a thickness of 1 μm to 100 μm, more preferably the layer (1) has a thickness of 60 to 150 nm and the layer (2) has a thickness of 50 to 15
0 nm, layer (3) 60-150 nm, layer (4) 5-20 μm
m, particularly preferably 60 to 120 nm for layer (1), 50 to 100 nm for layer (2), 60 to 120 nm for layer (3), and 5 for layer (4).
〜１０10 μm. The layer (4) preferably has a refractive index of 1.60 or less, and the layer (3) preferably has an intermediate refractive index between the layers (2) and (4).

FIG. 1 shows a typical example of the antireflection film of the present invention. A high refractive index layer 12 is formed on a transparent film (support) 13, and a low refractive index layer 11 is formed on the high refractive index layer 12. The increase in the number of layers constituting the anti-reflection film
Generally, the wavelength range of light to which the antireflection film can be applied is expanded.
This is based on the conventional principle of forming a multilayer film using a metal compound.

In the antireflection film having the two layers, the high refractive index layer 12 and the low refractive index layer 11 have the following conditions (1).
And (2) are generally satisfied. mλ / 4 × 0.7 <n ₁ d ₁ <mλ / 4 × 1.3 (1) nλ / 4 × 0.7 <n ₂ d ₂ <nλ / 4 × 1.3 (2) And m is a positive integer (generally 1, 2, or 3)
Where n ₁ represents the refractive index of the high refractive index layer, d ₁ represents the layer thickness (nm) of the high refractive index layer, and n is a positive odd number (generally,
1), n ₂ represents the refractive index of the low refractive index layer, and d ₂ represents the layer thickness (nm) of the low refractive index layer. The refractive index n ₁ of the high refractive index layer is generally at least 0.0
5 and the refractive index n ₂ of the low refractive index layer is generally at least 0.1 lower than the refractive index of the high refractive index layer and at least 0.05 lower than the transparent film. Furthermore, the refractive index n ₁ of the high refractive index layer is generally in the range of 1.7 to 2.2.
The above conditions (1) and (2) are conventionally well-known conditions, and are described, for example, in JP-A-59-50401.

FIG. 2 shows another typical example of the antireflection film of the present invention. An undercoat layer 20 and a medium refractive index layer 22 are formed on a transparent film (support) 23, and a high refractive index layer 24 is formed on the medium refractive layer 2.
2 and the low refractive index layer 21 is further formed on the high refractive index layer 2.
4 is formed. The refractive index of the medium refractive index 22 has a value between the high refractive index layer 24 and the undercoat layer 20. The antireflection film of FIG. 2 has a wider applicable wavelength range of light than the antireflection film of FIG.

In the case of an antireflection film having three layers, the medium, high and low refractive index layers generally satisfy the following conditions (3) to (5), respectively. hλ / 4 × 0.7 <n ₃ d ₃ <hλ / 4 × 1.3 (3) kλ / 4 × 0.7 <n ₄ d ₄ <kλ / 4 × 1.3 (4) jλ / 4 × 0.7 <n ₅ d ₅ <jλ / 4 × 1.3 (5) In the above formula, h is a positive integer (generally 1, 2, or 3)
And n ₃ represents the refractive index of the medium refractive index layer, d ₃ represents the layer thickness (nm) of the medium refractive index layer, and k is a positive integer (generally,
1, 2 or 3), n ₄ represents the refractive index of the high refractive index layer, d ₄ represents the layer thickness (nm) of the high refractive index layer, and j represents a positive odd number (generally, 1). , N ₅ represent the refractive index of the low refractive index layer, and d ₅ represents the layer thickness (nm) of the low refractive index layer. Refractive index n ₃ of the intermediate refractive index layer is generally in the range of 1.5 to 1.7, the refractive index n ₄ of the high refractive index layer is generally 1.7 to
It is in the range of 2.2.

The antireflection film of the present invention generally comprises a support and a low refractive index layer provided thereon. The support is usually a transparent film. Materials for forming the transparent film include cellulose derivatives (eg, diacetyl cellulose, triacetyl cellulose (TAC), propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, and nitrocellulose), polyamides, polycarbonates (eg, US Pat. No. 023,101), polyesters (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, poly-1,4-cyclohexane dimethylene terephthalate, polyethylene-1,2-diphenoxyethane-4,4'-di) Carboxylates and Tokiko Sho48
Patent No. -40414), polystyrene, polyolefins (eg, polyethylene, polypropylene and polymethylpentene), polymethylmethacrylate, syndiotactic polystyrene, polysulfone, polyethersulfone, polyetherketone, polyetherimide and polyoxy. Ethylene can be mentioned. Triacetyl cellulose, polycarbonate and polyethylene terephthalate are preferred. The refractive index of the transparent film is preferably from 1.40 to 1.60.

When the antireflection film of the present invention is a multilayer film, the low-refractive-index layer generally has at least one layer having a higher refractive index than the low-refractive-index layer. (Refractive index layer). As an organic material for forming a layer having a higher refractive index than the above, a thermoplastic resin (eg, polystyrene, polystyrene copolymer,
A polymer having an aromatic ring, a heterocyclic ring, an alicyclic group other than polycarbonate or polystyrene, or a polymer having a halogen group other than fluorine); a thermosetting resin composition (eg, a melamine resin, a phenol resin, or an epoxy resin) A curing agent); a urethane-forming composition (eg, a combination of an alicyclic or aromatic isocyanate and a polyol); and a radically polymerizable composition (a double bond is formed in the above compound (polymer or the like). A composition containing a modified resin or a prepolymer which is capable of radical curing by being introduced). Materials having high film forming properties are preferred. For the layer having a higher refractive index than the above, inorganic fine particles dispersed in an organic material can also be used. As the organic material used in the above, an inorganic fine particle generally has a high refractive index, so that a material having a lower refractive index than that when the organic material is used alone can also be used. As such materials, in addition to the organic materials described above, vinyl copolymers including acrylics, polyesters, alkyd resins, cellulose polymers,
Examples thereof include various organic materials which are transparent and stably disperse inorganic fine particles, such as urethane resins, various curing agents for curing these, and compositions having a curable functional group.

Further, an organic-substituted silicon-based compound can be included therein. These silicon compounds have the general formula: R ⁵¹ _m R ⁵² _n SiZ _(4-mn) (where R ⁵¹ and R ⁵² are an alkyl group, an alkenyl group, an allyl group, or a halogen, epoxy, amino, mercapto, Represents a hydrocarbon group substituted with methacryloyl or cyano, Z represents a hydrolyzable group selected from an alkoxyl group, an alkoxyalkoxyl group, a halogen atom and an acyloxy group, and under the condition that m + n is 1 or 2, , M and n are each 0, 1, or 2) or a hydrolysis product thereof.

Preferred inorganic compounds of the inorganic fine particles dispersed therein include oxides of metal elements such as aluminum, titanium, zirconium, and antimony. These compounds are commercially available in particulate form, ie, as a powder or as a colloidal dispersion in water and / or other solvents. These are further mixed and dispersed in the above organic material or organosilicon compound for use.

As the material for forming the layer having a higher refractive index, inorganic materials which are film-forming and can be dispersed in a solvent or are themselves liquid (eg, alkoxides of various elements, salts of organic acids, A coordination compound (eg, a chelate compound) bonded to a coordination compound, an active inorganic polymer) can be exemplified. Preferred examples thereof 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 Metal alcoholate compounds such as tetra-sec-butoxide and zirconium tetra-tert-butoxide; diisopropoxytitanium bis (acetylacetonate), dibutoxytitanium bis (acetylacetonate), diethoxytitanium bis (acetylacetonate), Bis (acetylacetone zirconium), aluminum acetylacetonate, aluminum di-n-butoxide monoethylacetoacetate,
Chelating compounds such as aluminum di-i-propoxide monomethyl acetoacetate and tri-n-butoxide zirconium monoethyl acetoacetate; and active inorganic polymers containing zirconium ammonium or zirconium as a main component. In addition to those described above, various alkyl silicates or hydrolysates thereof, particularly fine particles of silica, particularly silica gel dispersed in a colloidal form can be used as those having a relatively low refractive index but which can be used in combination with the above compounds. .

The antireflection film of the present invention can be treated so that the surface has an antiglare function (ie, a function of scattering incident light on the surface to prevent a scene around the film from shifting to the film surface). . For example, an antireflection film having such a function forms fine irregularities on the surface of a transparent film, and forms an antireflection film (eg, a low refractive index layer, etc.) on the surface.
Is obtained. The formation of the fine irregularities is performed, for example, by forming a layer containing inorganic or organic fine particles on the surface of the transparent film. 50nm ~ 2
The fine particles having a particle size of μm are added to the coating liquid for forming the low refractive index layer,
It may be introduced in an amount of 0.1 to 50% by weight to form irregularities on the uppermost layer of the antireflection film. An anti-reflection coating having an anti-glare function (ie, anti-glare treatment) generally has a haze of 3 to 30%.

The antireflection film of the present invention (preferably an antireflection film having an antiglare function) is used for a liquid crystal display (LC).
D), an image display device such as a plasma display (PDP), an electroluminescence display (ELD), and a cathode ray tube display (CRT).
In the image display device having such an antireflection film, reflection of incident light is prevented, and visibility is remarkably improved. A liquid crystal display (LCD) provided with the antireflection film of the present invention has, for example, the following configuration. A liquid crystal display comprising a pair of substrates having transparent electrodes, a nematic liquid crystal sealed between the substrates, and a polarizing plate disposed on both sides of the liquid crystal cell, wherein at least one of the polarizing plates has a surface on which the present invention is applied. Liquid crystal display device having an anti-reflection film.

In the present invention, a hard coat layer, a moisture proof layer, an electromagnetic wave absorbing layer, an antistatic layer and the like may be provided on the transparent film as an intermediate layer. As the hard coat layer, in addition to acrylic-based, urethane-based, and epoxy-based polymers and / or oligomers and monomers (eg, an ultraviolet curable resin), a silica-based material can also be used.

[0052]

The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.
In Examples, parts and% are by weight unless otherwise specified.

Example 1 (Synthesis of polymer particles) 1) Synthesis of methacrylate polymer particles (MP-8) 20 g of sodium dodecyl sulfate was dissolved in 1350 ml of distilled water in a two-liter three-necked flask equipped with a cooling pipe and a stirrer. Put the solution, then 100 g of methyl methacrylate
(1.00 mol), 80 g of n-butyl methacrylate
(0.56 mol) and 20 g (0.23 mol) of methacrylic acid 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 40 ml of an 8% aqueous sodium persulfate solution was added to carry out polymerization for 2 hours. Further, 40 ml of an 8% aqueous solution of sodium persulfate was added to carry out polymerization for 2 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 remove a fine milky white color. 2381 g of a liquid were obtained. This liquid was a fine latex liquid containing 8.4% by weight of nonvolatile components and having an average particle diameter of 74 nm. The particle size was evaluated by a dynamic light scattering method using a Coulter particle measuring device N4.

2) Acrylate polymer particles (AP-6)
A solution prepared by dissolving 50 g of sodium dodecyl sulfate in 1350 ml of distilled water was placed in a two-liter three-necked flask equipped with a cooling tube and a stirrer, and then 150 g (0.68 mol) of hexafluoroisopropyl acrylate and 2-acrylic acid
A mixed solution of 50 g (0.39 mol) of ethylhexyl 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 30 ml of an 8% aqueous sodium persulfate solution was added to carry out polymerization for 2 hours. Further, 50 ml of an 8% aqueous sodium persulfate solution was added, and polymerization was carried out for 2 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 removed by filtration to remove insoluble components to obtain a fine milky white liquid 212.
8 g were obtained. This liquid was a fine latex liquid containing 9.4% by weight of nonvolatile components and having an average particle diameter of 35 nm. The particle size was evaluated by a dynamic light scattering method using a Coulter particle measuring device N4.

The other acrylate particles and methacrylate particles used in the present invention can be easily synthesized by the same method as or a method similar to the above-mentioned emulsion polymerization method. (Formation of Hard Coat Layer) Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) 250
g was dissolved in 439 g of industrial denatured ethanol. A solution prepared by dissolving 7.5 g of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) and 5.0 g of a photosensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) in 49 g of methyl ethyl ketone was added to the obtained solution. added. After stirring the mixture, the mixture was filtered through a 1 μm mesh filter to prepare a coating solution for the hard coat layer. A triacetylcellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm is provided with a gelatin undercoat layer. The coating solution for the hard coat layer is coated on the gelatin undercoat layer with a bar coater. And dried at 120 ° C. Next, the coating layer was cured by irradiating ultraviolet rays to form a hard coat layer having a thickness of 6 μm.

(Preparation of low refractive index layer coating solution) 23.8 g of the methacrylate polymer particle liquid (MP-8) and 85.1 g of an acrylate polymer particle liquid (AP-6) were mixed.
191.1 g of water, 100 g of isopropyl alcohol and 100 g of methanol were added, stirred at room temperature, and filtered with a 1 μm mesh filter to prepare a coating solution for a low refractive index layer.

(Preparation of Antireflection Film) A coating liquid for a low refractive index layer is applied on the hard coat layer using a bar coater, dried at 120 ° C., and irradiated with an electron beam to cure the applied layer. Thus, a low refractive index layer (thickness: 0.1 μm) was formed. The electron beam was irradiated so as to have an illuminance of 15 Mrad using an electro-curtain laboratory machine CB-175 manufactured by Iwasaki Electric Co., Ltd.

(Preparation of Emboss Roll) Roll Diameter 100
After performing sand blasting of # 120 alumina particles on a polishing roll of mm and material S45C, hard chrome plating is applied to form a relatively long period irregularity rich shape with an in-plane irregularity pitch of 10 to 100 microns. did.
Subsequently, surface irregularities having a relatively short-period irregularity having an in-plane irregularity pitch of 1 to 10 μm on relatively long-period irregularities were formed on the roll by sandblasting of # 200 alumina particles. . A replica of the obtained embossing roll was prepared using a replica film of an acetylcellulose material (Bioden RFA 0.08 mm, obtained from Oken Trading Co., Ltd.), and evaluated by a scanning probe microscope. R
a is determined by Roughness analysis, and the ratio of the unevenness strength of 1 to 10 microns to the total unevenness strength is determined by Power Spectral Density.
As a result of quantification by analysis, 0.5 micron and 40 micron respectively
%Met.

(Providing Antiglare Property)
Single-sided embossing calendar machine (Yuri Roll Co., Ltd.)
Under the conditions of a press pressure of 1000 kg / cm, a preheat roll temperature of 100 ° C., an emboss roll temperature of 140 ° C., and a processing speed of 2 m / min, a steel emboss roll and a backup roll covered with a polyamide material were set. The embossing process was performed using the embossing roll made by the manufacturing method of the above. With respect to the obtained antiglare antireflection film, the average reflectance at a wavelength of 450 to 650 nm, the haze value and the pencil hardness of the surface were measured. As a result, the average reflectance was 1.0%, the haze was 1.5%, and the pencil hardness was H. And had a high texture without any visual roughness.

Example 2 (Preparation of titanium dioxide dispersion) 30 parts by weight of titanium dioxide (primary particle weight average particle diameter: 50 nm, refractive index: 2.70), anionic acrylate monomer (PM21, Nippon Kayaku Co., Ltd.) 4.5 parts by weight, 0.3 parts by weight of a cationic methacrylate monomer (DMAEMA, manufactured by Kojin Co., Ltd.) and 63 parts by weight of methyl ethyl ketone were dispersed by a sand grinder to prepare a titanium dioxide dispersion.

(Preparation of coating solution for medium refractive index layer) A photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) was added to 172 g of cyclohexanone and 43 g of methyl ethyl ketone.
0.18 g and 0.059 g of a photosensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) were dissolved. Further, 15.8 g of titanium dioxide dispersion and a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.)
3.1 g), and stirred at room temperature for 30 minutes.
The mixture was filtered through a filter having a mesh of m 2 to prepare a coating solution for a medium refractive index layer.

(Preparation of Coating Solution for High Refractive Index Layer) A photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) was added to 183 g of cyclohexanone and 46 g of methyl ethyl ketone.
0.085 g and a photosensitizer (Kayacure DETX,
0.028 g of Nippon Kayaku Co., Ltd.) was dissolved. further,
17.9 g of titanium dioxide dispersion and a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.)
1.0 g), and stirred at room temperature for 30 minutes.
The mixture was filtered through a filter having a mesh of m 2 to prepare a coating liquid for a high refractive index layer.

(Preparation of Antiglare Antireflection Film) On the hard coat layer formed in Example 1, a coating solution for a medium refractive index layer was applied using a bar coater, dried at 120 ° C., and then exposed to ultraviolet light. To cure the coating layer, the medium refractive index layer (thickness:
0.081 μm). A high-refractive-index layer coating solution is applied on the middle-refractive-index layer using a bar coater.
After drying, the coating layer was cured by irradiating ultraviolet rays to provide a high refractive index layer (thickness: 0.053 μm). On the high refractive index layer, the coating liquid for the low refractive index layer used in Example 1 was similarly applied using a bar coater, dried at 120 ° C., and irradiated with an electron beam to cure the coating layer. And a low refractive index layer (thickness: 0.092 μm). Thus, an antireflection film was formed. An antiglare property was imparted to the antireflection film by the same embossing treatment as in Example 1 except that a backup roll whose surface was covered with a silicone rubber material was used as the backup roll. About the obtained anti-reflection film,
The average reflectance, haze value, and pencil hardness of the surface at a wavelength of 450 to 650 nm were measured.
It had a haze value of 24%, a haze value of 2.0%, and a pencil hardness of 2H. The reflection of the background was greatly reduced, and the texture was high and there was no roughness on the visual perception.

Examples 3 to 10 The antiglare antireflection films 3-1 were prepared in the same manner as in Example 2 except that the compositions shown in Table 1 below were used for the coating solution for the low refractive index layer.
0 was created. Similarly, Comparative Examples 1 to 3 were prepared.
Table 1 also shows the results of measuring the average reflectance, the haze value, and the pencil hardness of the surface of the obtained film at a wavelength of 450 to 650 nm. Each of the antireflection films of the present invention was excellent in antireflection performance and surface hardness.

[0065]

[Table 1]

Example 11 The antiglare antireflection film prepared in Example 2 was adhered to the surface of a liquid crystal display device of a personal computer PC9821NS / 340W (manufactured by NEC Corporation). A high-quality display with reduced reflection of the background was obtained.

[0067]

According to the present invention, a composition containing (a) methacrylate monomer polymer particles and (b) acrylate monomer polymer particles simultaneously is applied, dried, and then irradiated with an electron beam to form a low refractive index layer. By forming the layer and setting the refractive index of the layer immediately below the layer to 1.7 or more, a large-area antireflection film having good optical characteristics and excellent film strength can be provided at low cost and in a form having suitability for production.

[Brief description of the drawings]

FIG. 1 shows a cross-sectional view of a typical example of an antireflection film of the present invention.

FIG. 2 is a cross-sectional view of another typical example of the antireflection film of the present invention.

[Explanation of symbols]

 11, 21: low refractive index layer 12, 24: high refractive index layer 22: medium refractive index layer 13, 23: transparent film 20: lower layer

Claims (6)

[Claims] 1. A methacrylate polymer fine particle containing at least 70% by weight of a repeating unit obtained by polymerizing a methacrylate monomer and decomposable by electron beam irradiation;
A composition obtained by uniformly mixing a composition containing acrylate polymer fine particles containing at least 70% by weight of a repeating unit obtained by polymerizing an acrylate or α-fluoroacrylate monomer on a support. An antireflection film having a refractive index layer. 2. The method according to claim 1, wherein the methacrylate polymer fine particles have a particle size of 200.
2. The composition according to claim 1, wherein said particles have an average particle size of not more than nm.
2. The antireflection film according to 1. 3. The method according to claim 1, wherein the acrylate polymer fine particles have a particle size of 200 n.
The anti-reflection film according to claim 1, wherein the anti-reflection film has an average particle size of not more than m. 4. The antireflection film according to claim 1, wherein the acrylate polymer fine particles contain a fluorine atom. 5. A methacrylate polymer fine particle containing 70% by weight or more of a repeating unit obtained by polymerizing a methacrylate monomer, and an acrylate or α
-After mixing with an acrylate polymer fine particle containing 70% by weight or more of a repeating unit obtained by polymerizing a fluoroacrylate monomer, coating on a support, drying, and then irradiating with an electron beam to form a void. A method for producing an antireflection film having a low refractive index layer, characterized by comprising: 6. An image display device comprising the antireflection film according to claim 1 on a front surface of an image display device.