JPH10221506A - Antireflection film and display having it arranged thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve film strength, durability, stain sticking resistance, and heat resistance by providing a layer containing polymer particles whose mean grain size is specific value or less and providing a low refractive index layer composed of a specific polymer. SOLUTION: It is an antireflection film layer which has polymer particles of means grain size 200nm or less, at least, a kind of the particles is α-fluoro- acrylic acid ester copolymer, and has a low refractive index layer. To provide this antireflection film with sufficient low refractive index, the quantity of microvoids (voids in the antireflection film) contained in a layer, which is composed of the α-fluoroacrylic acid ester copolymer particles, is preferable to be 3vol.%-50vol.%, more preferably 5vol.%-35vol.%. The film with the voids is manufactured by coating the film with the particles obtained by polymerization of the α-fluoroacrylic acid ester so that its fluorine content is improved and the low refractive index can be provided despite of being in the same porosity.

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.

Conventionally, as an antireflection film having a wide wavelength range and a low reflectance having a performance capable of covering the entire wavelength range of visible light, a multilayer film formed by laminating a transparent thin film such as a metal oxide has been used. Although a single-layer film is effective for monochromatic light, it cannot effectively prevent reflection of light having a certain wavelength range, whereas in such a multilayer film, the larger the number of layers, the wider the wavelength range. This is because it becomes an effective antireflection film. However, such an anti-reflection film formed by laminating three or more layers of metal oxides or the like by means of physical vapor deposition or the like is formed in accordance with the relationship between the refractive index and the film thickness of each layer which is optimally designed in advance. It was necessary to perform physical vapor deposition with the thickness controlled with high precision many times, it was very expensive, and it was not suitable for mass production, which was very difficult to obtain a large area film. . In addition, these multilayer deposition type antireflection films have poor anti-staining properties such as scratch resistance or fingerprint adhesion on the surface, and for this improvement, for example, a new layer made of a fluorine-containing resin is applied. Processing that could sacrifice antireflection was essential.

On the other hand, in addition to the above-described method using a multilayer film, a method for obtaining an effective anti-reflection effect by a film whose refractive index gradually changes at the interface with air is conventionally known. For example, JP-A-2-245702 discloses that
The SiO ₂ ultrafine particles and MgF ₂ ultrafine particles having an intermediate refractive index of the glass substrate and the MgF ₂ were mixed and applied to a glass substrate, gradually SiO toward the coating film surface from the glass substrate surface
_{It is described that when} the mixing ratio of MgF ₂ is increased by decreasing the mixing ratio of ₂ , the change in the refractive index at the interface between the coating surface and the glass substrate becomes gentle, and an antireflection effect is obtained. Further, JP-A-5-13021 discloses an antireflection film using ultrafine particles having a low refractive index, such as MgF ₂ or SiO _2, which has the smallest reflection when the ultrafine particles are regularly arranged on a substrate. It is stated that a rate is obtained.

In each of the above-mentioned methods, it is possible to provide a surface layer having a low reflectance.
Since the antireflection film described in JP-A-02-02206 can be obtained by stacking coating films having different mixing ratios in multiple layers, there is a problem that the film is complicated and difficult to control the refractive index.
In the antireflection film of JP-A-5-13021, it is difficult to gradually change the refractive index because the ultrafine particles in the outermost layer are covered with the binder, and the baking temperature is high. There were problems such as that the base material used was limited and that a sufficient antireflection effect could not be obtained.

[0006]

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.

[0007]

The above-mentioned problems are solved by the following antireflection film. (1) Reflection comprising a layer containing polymer fine particles having an average particle diameter of 200 nm or less, and at least one of the fine particles having a low refractive index layer which is an ester polymer of α-fluoroacrylic acid. Prevention film. (2) The antireflection film according to the above (1) or (2), wherein the formed low refractive layer contains voids of at least 3 volume percent or more. (3) The antireflection film according to the above (1) or (2), wherein at least one of the fine particles comprises a polymer containing a crosslinkable group. (4) The antireflection film according to the above (1) or (2), wherein at least one of the fine particles has a core-shell structure. (5) The antireflection film as described in (1) above, wherein the formed low refractive layer contains at least 0.3% by weight or more of fluorine atoms. (6) The antireflection film according to (1), wherein the low refractive index layer is formed on a layer having a higher refractive index. (7) The anti-reflection film according to the above (1), wherein the surface is subjected to anti-glare treatment. (8) A display device in which the antireflection film of (1) is arranged.

[0008]

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, “fine particles obtained by polymerizing an ester of α-fluoroacrylic acid” of the present invention are referred to as “fine particles”, and voids in an antireflection film obtained by forming the fine particles are referred to as “microvoids”.

In general, a method for providing an antireflection function by providing an ultra-thin layer having a refractive index as low as possible on the outermost surface of a substrate is known. In the present invention, the outermost surface layer (low refractive index layer)
-It is characterized in that fine particles obtained by polymerizing fluoroacrylic acid ester are used. FIG. 1 shows an antireflection film made of fine particles. In the figure, 1 is a layer in which air generated by microvoids between particles is mixed with a particle-forming polymer and a binder component forming a film (microvoid-containing layer).
And 3 is a substrate. The microvoids are uniformly dispersed in one layer. In addition, this microvoid layer
It is provided on the outermost surface of the transparent substrate to be subjected to antireflection.

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. In FIG. 2, a layer 2 having a refractive index higher than the refractive index of the substrate is provided on the substrate film, and further contains polymer fine particles obtained by polymerizing the α-fluoroacrylate ester of the present invention. 3 shows an antireflection film provided with a layer. 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-59-5
As disclosed in Japanese Patent Application Laid-Open No. 0401, the two-layer film has a refractive index n ₁ and a film thickness d ₁ of the first layer film in contact with the base material and a refractive index n ₂ of the second layer in contact with the first layer. 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 and n is an odd positive integer.

The present invention is characterized in that the microvoids introduced between the 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 microvoid-containing film is lowered by an amount corresponding to the use of the low refractive index α-fluoroacrylate polymer and the volume fraction of air introduced by the polymer fine particles. That is, the refractive index of this film is the refractive index of the component forming the film (having a value larger than 1) and the refractive index of the introduced air (which is 1.00).
And the result is a value lower than the refractive index of the used film-forming component.

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 monomer units of the α-fluoroacrylate polymer forming the fine particles of the present invention are those wherein the monomer is α
There is no particular limitation as long as it contains a fluorine atom at the position. As these monomers, those represented by the following formula can be preferably used. CH ₂ ＣＦCF—COOR In the formula, R represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms (eg, a methyl group, an ethyl group, an n-propyl group,
Isopropyl group, n-butyl group, isobutyl group, tert-
Butyl group, amyl group, cyclohexyl group, octyl group,
Dodecyl group, octadecyl group, 2-methoxyethyl group,
2,2,2-trifluoroethyl group, hexafluoroisopropyl group, 1H, 1H-perfluorooctyl group,
Perfluorocyclohexylmethyl group, 1H, 1H, 2
H, 2H-perfluorodecyl group, etc., and substituted or unsubstituted aryl groups (eg, phenyl group, naphthyl group, perfluorophenyl group, perfluorononylphenyl group, etc.).

The polymer forming the fine particles of the present invention includes, in addition to the above-mentioned α-fluoroacrylate monomer, α
A monomer having no fluorine atom at the position may be used in combination. 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 (eg, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate), styrene derivatives (eg, styrene, divinylbenzene, vinyltoluene, α-methylstyrene), and vinylyl ethers (eg, methyl vinyl ether) ), Vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tertbutylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides, Or the like can be mentioned acrylonitrile derivatives. Further, those containing a fluorine atom in the monomer can also be suitably used.

Specific examples of these monomers include, for example, fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.) Acrylic represented by the following general formula, partially or fully fluorinated alkyl ester derivatives of methacrylic acid, fully or partially fluorinated vinyl ethers, and the like. A polymer can be obtained.

[0016]

Embedded image

The refractive index of the polymer particles of the present invention decreases as the content of fluorine atoms in all the monomers used increases.
In order to sufficiently lower the refractive index of the anti-reflection coating of the present invention, it is preferable that the polymer contains 35 to 80% by weight of fluorine atoms, particularly preferably 45 to 75% by weight. .

The α-fluoroacrylic acid ester monomer used in the present invention can be prepared by the methods described in JP-A-7-188852, Japanese Patent No. 2509593, etc., and the corresponding α-fluoroacrylic acid derivatives and alcohols by the methods equivalent thereto. It can be easily synthesized from a class. The α-fluoroacrylic acid ester polymer fine particles used in the present invention can be easily synthesized by ordinary emulsion polymerization. Specific methods of emulsion polymerization are described in detail in books such as "Experimental Methods for Polymer Science" edited by The Society of Polymer Science, Tokyo Kagaku Dojin (1981), and these methods and methods equivalent thereto must be used. Can be.

As described above, the refractive index of the layer decreases as the content of microvoids increases. For this reason, in order for the antireflection film of the present invention to have a sufficiently low refractive index, the amount of microvoids contained in the layer composed of the α-fluoroacrylate polymer fine particles of the present invention is preferably 3% by volume to 50% by volume. Preferred, particularly preferred is 5% to 35% by volume.
% By volume.

As the polymer particles of the antireflection film in the present invention, either crystalline or amorphous polymer particles can be used.
In addition, the glass transition point (T
g) is not particularly limited, and from the viewpoint of maintaining voids during film formation,
It is preferable that Tg is equal to or higher than the film forming temperature. However, if the Tg is higher than the film forming temperature, the fusion of the particles is hindered, a continuous film is not formed, and there is a concern that the film strength is deteriorated. It is desirable to use a material whose effect is adjusted to an optimum region by Tg.

The α-fluoroacrylic acid ester 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.
Further, the α-fluoroacrylic acid ester polymer fine particles of the present invention may be used in combination with fine particles outside the present invention. In this case, the polymer fine particles outside the present invention to be used in combination are 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, It may be a water-soluble polymer (hereinafter referred to as a binder). The mixing ratio of the binder used in combination with the fine particles of the present invention is not particularly limited, but from the viewpoint of enhancing the film quality and introducing effective voids into the film, the fine particles of the present invention are preferably 30% by weight to 90% by weight. % By weight to 80% by weight are particularly preferred.

Further, the Tg of the binder used in combination is preferably lower than the Tg of the polymer component forming the fine particles of the present invention. Thereby, the binder used together is deformed at the time of film formation and serves as a binder between the fine particles of the present invention,
Sufficient film strength can be expected. However, the Tg of the binder used in combination is the Tg of the polymer component forming the fine particles of the present invention.
g, the microparticles of the present invention are deformed and microvoids are reduced. Therefore, the Tg of the binder used in combination is preferably 5 ° C. or more lower than the particles of the present invention.
It is particularly preferable that the temperature is lower than 20 ° C. in consideration of the width of g and the fluctuation of the film forming temperature.

Also, the fine particles and the combined binder can react with each other by radiation energy such as light or electron beam or heat energy such as heating or electromagnetic wave to introduce a crosslinkable functional group, thereby also causing a cross-linkage between particles. The film strength can be improved by the formation of covalent bonds. The thing which can be suitably used as a crosslinkable group is not particularly limited as long as it is a functional group which reacts by radiation or heat, and examples thereof include an isocyanate group, a block isocyanate group, an epoxy group, an aziridine group, an oxazoline group, and an aldehyde group. , Carbonyl group, hydrazine group, carboxyl group, methylol group, in addition to compounds having an active methylene group, vinyl sulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester, functional group selected from urethane and the like Including particles. Further, in the present invention, the cross-linking group is not limited to the above-mentioned compound, but may be one which shows reactivity as a result of decomposition of the above-mentioned functional group. The crosslinkable compound to be used may be a combination of two or more compounds having a group capable of reacting with each other, or a compound having a plurality of self-crosslinkable groups such as a vinyl group and an active methylene group in a molecule. May be. Further, it is preferable that the fine particles have a core-shell structure and the shell has a crosslinkable group.

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.

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 are preferable. 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, vinyl copolymers including acrylics, polyester (including alkyd) polymers,
Various organic materials that can stably disperse inorganic fine particles such as cellulose polymer, urethane polymer, and various curing agents that cure them, and compositions having curable functional groups can be used. is there. 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.

Examples of 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.

The layers forming the anti-reflection layer of the present invention may be formed by generally known methods, for example, dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, or US It can be applied by an extrusion coating method using a hopper described in Japanese Patent No. 2,681,294. Also, if necessary, U.S. Pat.
No. 761,791, 3,508,947, 2,94
No. 1,898 and 3,526,528, and two or more layers can be coated simultaneously 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 scenery and the like. The anti-reflection film may be used alone or in combination with an anti-glare effect in a liquid crystal display (LCD),
Plasma display (PDP), electroluminescence display (ELD), cathode ray tube display (CR
By applying the present invention to an image display device such as T) and preventing reflection of external light, visibility can be significantly improved.

[0033]

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 α-fluoroacrylate monomer (FM-2)) 1) Synthesis of hexafluoroisopropyl α-fluoroacrylate One liter was placed in a two-liter three-necked flask equipped with a cooling tube, a thermometer and a stirrer. Of xylene, 20 g of dimethylacetamide and 112.0 g (1.0 mol
l) α-Fluoroacrylic acid sodium salt is added and stirred at room temperature. 51.0 g of thionyl chloride was added to this mixture.
(0.43 mol) is added dropwise over 1 hour. Next, the reaction mixture was reacted at 80 ° C. for 2 hours, cooled to 0 ° C., and treated with 180.0 g of hexafluoroisopropanol.
(1.07 mol) and 108.1 g of triethylamine
(1.07 mol) was added dropwise over 1 hour. After stirring the obtained reaction solution at room temperature for 30 minutes, insolubles were removed, 0.5 g of p-methoxyphenol was added, and the mixture was distilled to obtain 121.3 g of a colorless transparent liquid having a boiling point of 95 ° C to 100 ° C. Obtained as a fraction. Yield 50.5%.

The other α-fluoroacrylic acid ester monomers of the present invention could be easily synthesized by the same method as described above or a method analogous thereto. The α-fluoroacrylic acid ester monomers of the present invention synthesized by these methods are summarized below.

FM-1 Methyl α-fluoroacrylate FM-2 Hexafluoroisopropyl α-fluoroacrylate FM-3 Tert-butyl α-fluoroacrylate FM-4 Cyclohexyl α-fluoroacrylate FM-5 α-Fluoroacryl 2,2,2-trifluoroethyl acid FM-6 α-fluoroacrylic acid 1H, 1H, 2H,
2H-perfluorodecyl FM-7 perfluorocyclohexylmethyl α-fluoroacrylate FM-8 1H, 1H-perfluorooctyl FM-9 FM-9 ethyl glycol-di-α-fluoroacrylate FM-10 α-fluoro Perfluoro-tert-acrylate
-Butyl

(Synthesis of Polymer Fine Particles) 1) Synthesis of FP1 20 g of sodium dodecyl sulfate was placed in a 2 liter three-necked flask equipped with a cooling pipe and a stirrer, and distilled water (1350 m) was used.
of the solution dissolved in α-fluoroacrylic acid hexafluoroisopropyl ester 180 g (0.1 g).
75 mol) and 18 g (0.14 mol) of divinylbenzene
Was added and stirred at a speed of 200 rpm under a nitrogen stream. This reaction vessel was heated to 75 ° C., and 40 ml of an 8% aqueous solution of sodium persulfate was added to carry out polymerization for 2 hours. Further, 40 ml of an 8% aqueous sodium persulfate solution was added, and polymerization was performed 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. 2160 g of an aqueous solution was obtained. This solution was a fine latex liquid containing 9.1% by weight of nonvolatile components and having an average particle diameter of 36 nm. The particle size was evaluated by a dynamic light scattering method using a Coulter particle measuring device N4.

2) Synthesis of FP2 In a 2 liter three-necked flask equipped with a cooling tube and a stirrer, 50 g of sodium dodecyl sulfate was placed in 1350 m of distilled water.
of α-fluoroacrylic acid 1H, 1H-perfluorooctyl ester 150 g
(0.32 mol), 45 g (0.32 mol) of methacrylic acid tert-butyl ester and 30 g of divinylbenzene
(0.23 mol), and the mixture was added under nitrogen stream for 20 minutes.
The mixture was stirred at a speed of 0 rpm. This reaction vessel was heated to 75 ° C., and 30 ml of an 8% aqueous solution of sodium persulfate was added to carry out polymerization for 2 hours. Furthermore, after adding 50 ml of an 8% aqueous sodium persulfate solution and polymerizing for 2 hours, the reaction solution was cooled to room temperature and dialyzed using a cellulose membrane having a molecular weight cut off of 10,000 to remove excess surfactant and inorganic salts. The insoluble matter was removed by filtration and filtration to obtain 2960 g of a fine milky white aqueous solution.
This solution had an average particle size of 57% containing 7.6% by weight of nonvolatile components.
It was a fine latex liquid of nm. The particle size was evaluated by a dynamic light scattering method using a Coulter particle measuring device N4.

The other void particles used in the present invention could be easily synthesized by the same method as the above-mentioned emulsion polymerization method or a method similar thereto. The void microparticles (FP1 to FP7) of the present invention synthesized by these methods are summarized in Table 1 below.

[0040]

[Table 1]

Example 1 (Coating of antireflection layer and evaluation of performance)

Using the fine particles shown in Table 1 above, Table 2
Aqueous solutions (E1 to E10) prepared by the above composition were applied onto a triacetylcellulose (hereinafter referred to as TAC) film using a spin coater, dried at 80 ° C. for 60 minutes, and dried.
A low refractive index layer of 00 nm was formed. The obtained film (X1
For X10), the measurement of the refractive index, the porosity, the luminous reflectance and the film surface strength were performed. For the porosity of the low refractive index layer, the refractive index of the layer was measured, and the volume fraction of air was calculated backward from the difference from the calculated value of the refractive index of the layer obtained from the composition of the layer components used. The surface strength of the film was determined by rubbing with a fingertip, a tissue, and an eraser, visually observing, xx for those that were scratched by rubbing the fingertip, x for those that were scratched by rubbing the tissue, and △ for those that were scratched by rubbing the eraser. A sample in which no was observed was evaluated as ○. The results are shown in Table 3.

[0043]

[Table 2]

[0044]

[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 NP2) outside the present invention as shown in Table 2, and the comparative sample solution coating solution (F1 to F4) was prepared and formed into a film under the same conditions to obtain comparative samples (Y1 to Y4). The obtained film was subjected to the same method as in Example 1 to obtain a film having a refractive index and a luminous reflectance (a light wavelength of 400).
(mean reflectance value from nm to 800 nm) and film strength measurement with a sapphire needle. The results are shown in Table 3.

Example 2 (Preparation of multilayer antireflection film) (1) Coating of first layer (hard coat layer) A TAC film having a thickness of 90 μm was coated with 5% by weight of dipentaerythritol hexaacrylate and light. Polymerization initiator (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:
HP1) 100 g and tin oxide fine particles (obtained from Ishihara Sangyo Co., Ltd.) 25 g were mixed, further, dipentaerythritol hexaacrylate 6 g, and a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Geigy) 0 .5
g, 0.2 g of a photosensitizer (trade name: Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) An emulsion liquid obtained by emulsifying and dispersing 20 g of ethyl acetate in 100 g of water using 1 g of sodium dodecylbenzenesulfonate was mixed and stirred. A coating solution was prepared.
This liquid was applied to a thickness of 0.16 μm on the first layer prepared above using a wire bar, and after drying,
C. and cross-linked by irradiating with ultraviolet rays for 1 minute using a 12 W / cm high-pressure mercury lamp, and then allowed to cool to room temperature.

(3) Preparation of Third Layer (Low Refractive Index Layer) 6 g of dipentaerythritol hexaacrylate, 0.5 g of photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba-Geigy), photosensitizer ( Product Name: Kaya Cure DE
TX, manufactured by Nippon Kayaku Co., Ltd.) 0.2 g of ethyl acetate 20 g of sodium dodecylbenzenesulfonate in 10 g of water
A coating solution was prepared by mixing and stirring 100 g of the previously synthesized latex FP1 and the emulsion liquid emulsified and dispersed in 0 g. This liquid was applied to a thickness of 0.10 μm using a wire bar on the second layer prepared above, and after drying,
The mixture was heated to 100 ° C. and irradiated with ultraviolet rays for 1 minute using a high-pressure mercury lamp of 12 W / cm for crosslinking. Then, it was allowed to cool to room temperature. The thus-obtained film coated with the first to third layers exhibits a surface reflectance of 0.4% of the visual perception, and the surface physical properties of the film surface strength に よ る (by the method described in Example 1). (Anti-reflection film: ARF1).

The antireflection film A was prepared in the same manner as in the above example except that HP1 and FP1 were made of the materials shown in Table 4 below, and the amount of liquid preparation was changed so that the solid content concentration of the coating solution was the same.
RF2 to 6 were obtained. Table 4 shows the surface performance of these films.
Are shown together. At the same time, the compound used for the third layer was changed to particles NP1 to NP3 outside the present invention, and the amount of the liquid preparation was changed so that the solid content concentration of the coating solution was the same. 3 was obtained. These surface performances are also shown in Table 4.

[0050]

[Table 4]

As is clear from this example, the antireflection film of the present invention not only has a very low reflectance and an excellent antireflection performance having 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 X2 prepared in Example 2 was obtained from a personal computer PC obtained from NEC Corporation.
A sample was attached to the surface of a 9821NS / 340W liquid crystal display to prepare a display device sample, and the degree of reflection of the scenery by surface reflection was visually evaluated. Similarly, display device samples were prepared using the films X3, X5, Y1, and Y3 prepared in Example 2 as the antireflection films used in the above method. The antireflection films X2, X3 of the present invention,
The display device on which X5 was installed showed almost no reflection of the surrounding scenery and showed comfortable visibility, whereas the comparison film X
2. The display device with X3 installed has many reflections around it,
The visibility was poor.

[0053]

According to the present invention, the fluorine content in the film is improved by forming a film having voids by coating the film with fine particles obtained by polymerizing α-fluoroacrylate. Even with the same porosity, a film having a lower refractive index can be obtained. 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 made of a layer comprising a fluoropolymer fine particle of the present invention.

FIG. 2 shows a layer comprising the fluoropolymer fine particles of the present invention,
FIG. 2 shows a cross-sectional view of an antireflection film made of a layer having a higher refractive index than a substrate.

[Explanation of symbols]

 1 low refractive index layer 2 high refractive index layer 3 substrate

Claims (8)

[Claims] 1. A low refractive index layer having a layer containing polymer fine particles having an average particle diameter of 200 nm or less, wherein at least one of the fine particles is a polymer obtained by polymerizing an ester of α-fluoroacrylic acid. An anti-reflection film comprising: 2. The antireflection film according to claim 1, wherein the formed low refractive index layer contains at least 3% by volume of voids. 3. The antireflection film according to claim 1, wherein at least one of the fine particles is made of a polymer containing a crosslinkable group. 4. The anti-reflection film according to claim 1, wherein at least one of the fine particles has a core-shell structure. 5. The method according to claim 1, wherein the formed low refractive layer has a thickness of at least 0.3.
2. The antireflection film according to claim 1, wherein the antireflection film contains a fluorine atom in a weight fraction or more. 6. The antireflection film according to claim 1, wherein said low refractive index layer is formed on a layer having a higher refractive index. 7. The anti-reflection film according to claim 1, wherein the surface is subjected to an anti-glare treatment. 8. A low refractive index layer having a layer containing polymer fine particles having an average particle size of 200 nm or less, wherein at least one of the fine particles is a polymer obtained by polymerizing an ester of α-fluoroacrylic acid. A display device comprising an anti-reflection film having the following.