JP2008122837A - Antiglare antireflection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antiglare antireflection film which has both excellent transmission image clearness and an antiglare characteristic. <P>SOLUTION: The antiglare antireflection film has a low refractive index layer on at least one surface of a transparent film and the low refractive index layer has very loose and minute irregularity and a specific shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antiglare antireflection film.

In various image display devices such as a liquid crystal display device (LCD) and a plasma display panel (PDP), it may be difficult to see a display image due to reflection of light incident from the outside on the screen. Particularly in recent years, with the increase in the size of image display devices, it has become increasingly important to solve the above problems.
In order to solve such a problem, the antiglare treatment is performed on the LCD by forming fine irregularities on the surface. Conventionally, as an anti-glare treatment method, sandblasting, embossing, formation of a coating film containing fine particles, and the like have been performed. For example, as a method for producing an anti-glare hard coat film with controlled transmission light scattering characteristics and improved glare, an active energy ray curable resin is applied to a transparent plastic substrate and irradiated with active energy rays. There has been proposed a method of curing and forming an active energy ray-curable resin layer and then subjecting the coating to either sandblasting or embossing. (Patent Document 1)
In addition, when forming an antiglare layer of an antiglare film with a coating liquid composed of a light-transmitting fine particle, a light-transmitting resin, and a good solvent and a poor solvent of the light-transmitting resin, the light-transmitting effect is caused by the action of the poor solvent during the drying process Disclosed is a method for forming a good concavo-convex structure by gelling conductive fine particles and translucent resin. (Patent Document 2)

On the other hand, in a PDP, an antireflection film using light interference is often installed. Specifically, in the case of a single-layer antireflection film, when the refractive index of the substrate is n _s , and the refractive index of the single-layer film is n and n _s > n, the reflectance R is set to a minimum value ( _ns − ^{_{n 2) 2 / (n s}} + n 2) 2 utilize to ^take, reducing the reflectance close to the refractive index n of the single-layer film such that n 2 = _{n s} in _(n ^{s) 1/2} It is something to be made. Currently, many commercially available optical members having an antireflection film have a luminous reflectance around 2% in the visible light region. There are various low-refractive-index materials for such an antireflection film, and a fluororesin is generally known as a material for forming a low-refractive-index film by a coating method. (Patent Document 3)
As a method of forming a low refractive index film, hollow silica fine particles are used for the low refractive index layer, and a space between the hollow silica fine particles is filled with a second binder to reinforce the bond between the hollow silica fine particles and increase the wear resistance. A method of improving (Patent Document 4) is disclosed. The method for producing hollow silica fine particles is described in detail, for example, in (Patent Document 5).

However, in the PDP, the reflectance of external light can be lowered by an antireflection film, but the image of what is reflected is clear, so the visibility of what is desired to be displayed is not sufficient. On the other hand, when the anti-glare processing used for LCDs is applied to the PDP, although the sharpness of what is reflected by the reflection of outside light is low, the transmitted image itself that is originally intended to be projected is blurred by the anti-glare processing. There was a problem. This is because PDP differs from LCD in that PDP has to install an anti-glare treatment or an antireflection film on the surface of the optical filter that is far from the light emitting part.
That is, in PDP, it is very difficult to achieve both contradictory functions such that the reflection by external light and the transmitted image are clear.

Japanese Patent Laid-Open No. 11-352899 JP 2000-338310 A JP-A-4-355401 JP 2004-258267 A JP 2006-21938 A

  That is, an object of the present invention is to provide an antiglare antireflection film that solves the above-mentioned problems and has excellent transmitted image definition and also has excellent antiglare properties.

As a result of intensive studies in order to solve the above problems, the present inventors have anti-glare reflection in which a low refractive index layer having a refractive index lower than that of the transparent film is provided on at least one surface of the transparent film. The anti-glare antireflection film provided with a low refractive index layer having a very gentle and fine irregularities and a specific shape can be achieved in the anti-reflection film, and based on this finding, the present invention It came to complete.
That is, the present invention
(1) In an antiglare antireflection film in which a low refractive index layer having a refractive index lower than the refractive index of the transparent film is provided on at least one surface of the transparent film, the low refractive index layer has a centerline average An antiglare antireflection film having a roughness Ra of 0.005 to 0.05 μm, an average gradient Δa of 0.005 to 0.05 rad, and a surface shape having a droplet-like structure.

(2) The antiglare antireflection film according to claim 1, wherein the droplets having the droplet-like structure have an average diameter of 1 to 150 μm and an average distance between the droplet centers of 5 to 300 μm.
(3) The anti-glare antireflection film according to claim 1 or 2, wherein the low refractive index layer contains silica fine particles and a binder, and the average particle size of the silica fine particles is 3 to 200 nm.
(4) The thickness of the low refractive index layer is 50 to 300 nm, the minimum reflectance at an incident angle of 5 degrees is 2% or less, and the minimum reflectance wavelength is in the range of 500 to 750 nm. The anti-glare antireflection film according to any one of 1 to 3.

  According to the present invention, since it is possible to provide an antiglare antireflection film having excellent transmitted image definition and having excellent antiglare properties, it can be used to reflect external light in various image display devices, particularly PDPs. On the other hand, it is useful and is excellent in transmitted image definition, so that visibility can be increased.

The present invention will be specifically described below.
As a transparent film that can be used in the present invention, for example, polyethylene film, polypropylene film, cellulose acetate film such as triacetyl cellulose, cellulose acetate propionate, polyester film such as stretched polyethylene terephthalate, polyethylene naphthalate, Examples thereof include a polycarbonate film, a norbornene film, a polysulfone film, a polyethersulfone film, and a polyarylate film. The transparent film has a haze of preferably 0.01% or more and 2.0% or less, and more preferably 0.01% or more and 1.0% or less, from the viewpoint of utilization of transmitted light.

The antiglare antireflection film of the present invention can be provided with an antireflection function by sticking to the surface using an adhesive or the like on the surface on which antireflection is desired. As the surface to which an antireflection function is desired, glass is the most, and it can also be used for acrylic resins. Therefore, from the viewpoint of the antireflection function, a transparent film having a refractive index of 1.45 or more and 1.69 or less, and a triacetyl cellulose film or a polyethylene terephthalate film is preferably used.
Among these transparent films, a triacetyl cellulose film (hereinafter referred to as a TAC film) has excellent optical properties from the viewpoint of wavelength dispersion, and therefore, when continuously producing the antiglare antireflection film of the present invention. Most preferably used. The thickness of the TAC film is preferably 25 μm or more from the viewpoint of uniformity of the thickness of the low refractive index layer and handleability as an optical substrate. The upper limit with the preferable thickness of a TAC film is 200 micrometers from a viewpoint of light transmittance and the utilization efficiency of light.

In the antiglare antireflection film of the present invention, a low refractive index layer having a refractive index lower than the refractive index of the transparent film is provided on at least one surface of the transparent film. By providing this low refractive index layer, the reflectance of external light reflection can be reduced, and at the same time, a reflected image due to external light can be blurred. The low refractive index layer has a lower refractive index than the lower layer in order to reduce the reflectance of external light, and the thickness of the low refractive index layer is preferably 50 to 300 nm.
Here, the thickness of the low refractive index layer is an average value of thicknesses obtained by observing an arbitrary 30 points of the cross section of the antiglare antireflection film with an electron microscope. If the thickness is too thin or too thick, the antireflection effect in the visible light region is reduced.

The low refractive index layer of the present invention is characterized in that the center line average roughness Ra is in the range of 0.005 to 0.05 μm and the average inclination gradient Δa is in the range of 0.005 to 0.05 rad. When the center average roughness Ra is smaller than 0.005 μm, the reflected image definition cannot be lowered, and it is difficult to sufficiently reduce the reflection. On the other hand, if the center line average roughness Ra is larger than 0.05 μm, the transmitted image definition is lowered, which is not preferable.
When the average inclination gradient Δa is smaller than 0.005 rad, the reflected image definition cannot be lowered, and it is difficult to sufficiently reduce the reflection. If the average inclination gradient Δa is greater than 0.05 rad, the reflection of the reflected image can be reduced, but it is not preferable because it looks whitish in appearance and the transmitted image sharpness decreases. The centerline average roughness Ra and the average slope gradient Δa are measured by the methods described in the examples.

  The low refractive index layer of the present invention has a center line average roughness Ra of 0.005 to 0.05 μm and an average inclination gradient Δa of 0.005 to 0.05 rad, and further has a droplet-like structure as a macro shape. It is characterized by having. The droplet-like structure refers to a pattern in which minute droplets are dispersed on the surface of the low refractive index layer. FIG. 1 shows an example of a surface shape difference differential image of a droplet-like structure. The average droplet diameter of the droplet-like structure (a in FIG. 1) is preferably 1 to 150 μm, more preferably 5 to 130 μm, and most preferably 10 to 100 μm. Here, the average droplet diameter is an average value of the diameters of 20 arbitrarily selected droplet structures. The average center distance between adjacent droplets (b in FIG. 1) is preferably 5 to 300 μm, more preferably 10 to 200 μm. Here, the average center-to-center distance is an average value of the center-to-center distances of 20 arbitrarily selected droplets. When the average droplet diameter and average center-to-center distance of the droplet-like structure are in a specific range, the antiglare effect and the sharpness of the transmitted image are further preferable. As a tendency, if the average center-to-center distance is larger than 300 μm, the reflected image becomes difficult to blur and the effect of sufficiently reducing the transfer of outside light becomes low. When the average center-to-center distance is smaller than 5 μm, white blurring tends to occur on the antiglare antireflection film surface.

It is preferable that the droplet area occupied ratio of the droplet-like structure is 10 to 75%. By setting the content to 10 to 75%, excellent transmitted image clarity and antiglare properties are exhibited. Here, the droplet portion area occupancy is the occupancy of the total area occupied by the droplet-like structure with respect to the measurement area of the surface shape height difference differential image.
In the antiglare antireflection film of the present invention, the sum of transmitted image sharpness measured with four types of optical combs defined in JIS K7105 is preferably 350% or more and 400% or less, and more preferably 370% or more and 399% or less. The sum of the 45-degree reflected image definition is preferably 5% or more and 300% or less, and more preferably 20% or more and 250% or less. If the sum of the transmitted image sharpness is less than 350%, the resolution of the transmitted image tends to decrease. If the sum of the 45-degree reflected image sharpness exceeds 300%, the anti-glare property decreases, and external light Since the sharpness of the image due to the reflection is high, the visibility of the display image tends to decrease.

  The low refractive index layer preferably has a configuration containing silica fine particles and a binder. The combination of the silica particles and the binder makes it easy to control the surface shape of the low refractive index layer. Silica fine particles may or may not have cavities inside. In view of dispersibility, surface properties of the resulting layer, and mechanical strength, it is preferable to use those having an average particle size of 200 nm or less. When the average particle diameter exceeds 200 nm, haze increases, and white blurring tends to occur on the antiglare antireflection film surface.

  The use of hollow silica fine particles having cavities inside the particles as the silica fine particles is preferable because the refractive index of the low refractive index layer can be lowered. Since the cavity is surrounded by the outer shell, the binder does not enter the cavity. The presence of the cavity can reduce the refractive index, and the blocking of the binder from entering the cavity can prevent an increase in the refractive index. A refractive index can be lowered in the refractive index layer. The average particle diameter of the hollow silica fine particles is preferably 40 to 200 nm. When the hollow silica fine particle diameter is larger than 200 nm, the refractive index decreases when the thickness of the outer shell surrounding the cavity is almost constant, but the strength of the hollow silica fine particle tends to be weak, and the surface When the unevenness becomes too large, the transmitted image definition tends to decrease, or the haze increases and white blurring of the antiglare antireflection film surface tends to occur. If the hollow silica fine particles are smaller than 40 nm, the strength is increased, but it is difficult to lower the refractive index. The refractive index is a very large factor because it correlates with the cube of the particle diameter. From these viewpoints, those having an average particle diameter of 60 to 200 nm are particularly preferably used.

The refractive index of the hollow silica fine particles is preferably 1.40 or less from the viewpoint of lowering the refractive index of the low refractive index layer. When the refractive index is greater than 1.40, the effect of reducing the refractive index is low. A refractive index of 1.10 to 1.35 is preferably used. The refractive index of the hollow silica fine particles is measured by the method described in the examples.
The refractive index can also be controlled by the thickness of the outer shell surrounding the hollow silica fine particle cavity. As the thickness of the outer shell, a dense one having a thickness of 3 nm or more, particularly 4 nm or more and 12 nm or less is preferably used. When the thickness is thin, the refractive index of the hollow silica fine particles can be lowered, but there is a case where destruction occurs from the viewpoint of the strength of the hollow silica fine particles themselves. On the other hand, since the refractive index of the thick outer shell does not become low, the effect of lowering the refractive index is low.

The average particle size of silica fine particles having no voids inside is usually expressed by the average particle size (nm) = (2720 / specific surface area) from the specific surface area (m ² / g) measured by the nitrogen adsorption method (BET method). The value given by the expression. The average particle diameter of the hollow silica fine particles refers to the particle diameter determined with a transmission electron microscope. The magnification was the magnification at which 5 or more particles entered the photograph, the outer diameters of all the particles present on the screen were measured, and the average value was obtained.
Two or more types of silica fine particles or hollow silica fine particles may be used in combination.
Next, the binder contained in the low refractive index layer will be described.
The binder may be used alone or in combination. The following are mentioned as a preferable binder.

(1) Tetramethoxysilane, tetraethoxysilane, tetra (i-propoxy) silane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxy Silane, propyltriethoxysilane, isobutyltriethoxysilane, methyltri-iso-propoxysilane, ethyltri-iso-propoxysilane, dimethoxysilane, diethoxysilane, methyldimethoxysilane, methyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane Diethyldimethoxysilane, diethyldiethoxysilane, diethyldi (i-propoxy) silane, methylethyldimethoxysilane, methylethyldiethoxysilane , Methylethyldi (i-propoxy) silane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, methylpropyldi (i-propoxy) silane, methoxysilane, ethoxysilane, methylmethoxysilane, methylethoxysilane, dimethylmethoxysilane, dimethyl Ethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, trimethyl (i-propoxy) silane, triethylmethoxysilane, triethylethoxysilane, triethyl (i-propoxy) silane, tripropylmethoxysilane, tripropylethoxysilane, tripropyl (i- Propoxy) silane, methyldiethylmethoxysilane, methyldiethylethoxysilane, methyldiethyl (i-propoxy) silane, methyldipropylmeth Sisilane, methyldipropylethoxysilane, methyldipropyl (i-propoxy) silane, ethyldimethylethoxysilane, ethyldimethyl (i-propoxy) silane, ethyldipropylmethoxysilane, ethyldipropylethoxysilane, ethyldipropyl (i- Propoxy) silane, propyldimethylmethoxysilane, propyldimethylethoxysilane, propyldimethyl (i-propoxy) silane, propyldiethylmethoxysilane, propyldiethylethoxysilane, propyldiethyl (i-propoxy) silane, bis (trimethoxysilyl) methane, Bis (triethoxysilyl) methane, bis (trimethoxysilyl) ethane, bis (triethoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,3-bis ( Triethoxysilyl) propane, hexamethoxydisiloxane, hexaethoxydisiloxane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- Mercaptopropyltriethoxysilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltri Ethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, tetraacetoxysilane, tetrakis (trichloroacetoxy) silane, tetrakis (trifluoroacetate) Xyl) silane, triacetoxysilane, tris (trichloroacetoxy) silane, tris (trifluoroacetoxy) silane, methyltriacetoxysilane, methyltris (trichloroacetoxy) silane, methyltris (trifluoroacetoxy) silane, methyldiacetoxysilane, methylbis ( Trichloroacetoxy) silane, methylbis (trifluoroacetoxy) silane, dimethylbis (trichloroacetoxy) silane, dimethylbis (trifluoroacetoxy) silane, methylacetoxysilane, methyl (trichloroacetoxy) silane, methyl (trifluoroacetoxy) silane, dimethyl Acetoxysilane, dimethyl (trichloroacetoxy) silane, dimethyl (trifluoroacetoxy) silane, trimethylacetoxy Run, trimethyl (trichloroacetoxy) silane, trimethyl (trifluoroacetoxy) silane, tetrachlorosilane, tetrabromosilane, tetrafluorosilane, trichlorosilane, tribromosilane, trifluorosilane, methyltrichlorosilane, methyltribromosilane, methyltri Fluorosilane, methyldichlorosilane, methyldibromosilane, methyldifluorosilane, dimethyldichlorosilane, dimethyldibromosilane, dimethyldifluorosilane, methylchlorosilane, methylbromosilane, methylfluorosilane, dimethylchlorosilane, dimethylbromosilane, dimethylfluorosilane, trimethyl Hydrolyzable silanes such as chlorosilane, trimethylbromosilane, and trimethylfluorosilane.

(2) 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltriacetoxysilane, 3-acryloxypropyltris (trichloroacetoxy) silane, 3-acryloxypropyltris (trifluoroacetoxy) silane, 3-methacryloxypropyltriacetoxy Silane, 3-methacryloxypropyltris (trichloroacetoxy) silane, 3-methacryloxypropyltris (trifluoroacetoxy) silane, 3-glycidoxypropyltriacetoxysila 3-glycidoxypropyltris (trichloroacetoxy) silane, 3-glycidoxypropyltris (trifluoroacetoxy) silane, 3-acryloxypropyltrichlorosilane, 3-acryloxypropyltribromosilane, 3-acryloxypropyl Trifluorosilane, 3-methacryloxypropyltrichlorosilane, 3-methacryloxypropyltribromosilane, 3-methacryloxypropyltrifluorosilane, 3-glycidoxypropyltrichlorosilane, 3-glycidoxypropyltribromosilane, A reactive silane compound having both a polymerizable functional group and a functional group capable of forming a covalent bond with silica particles in the same molecule, such as 3-glycidoxypropyltrifluorosilane.

(3) Silicic acid, trimethylsilanol, triphenylsilanol, dimethylsilanediol, diphenylsilanediol, silanol terminated polydimethylsiloxane, silanol terminated polydiphenylsiloxane, silanol terminated polymethylphenylsiloxane, silanol terminated polymethyl ladder siloxane, silanol terminated poly Silicon compounds containing silanol groups such as phenyl ladder siloxane and octahydroxy octasilsesquioxane.
(4) Water glass, sodium orthosilicate, potassium orthosilicate, lithium orthosilicate, sodium metasilicate, potassium metasilicate, lithium metasilicate, tetramethylammonium orthosilicate, tetrapropylammonium orthosilicate, tetramethylammonium metasilicate, metasilicate Active silica obtained by bringing a silicate such as tetrapropylammonium into contact with an acid or ion exchange resin.

(5) Polyethers such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, polyacrylamide derivatives, polymethacrylamide derivatives, amides such as poly (N-vinylpyrrolidone) and poly (N-acylethyleneimine), polyvinyl Organic polymers such as alcohols, polyvinyl acetate, polyacrylic acid derivatives, polymethacrylic acid derivatives, esters such as polycaprolactone, polyimides, polyurethanes, polyureas, and polycarbonates. These organic polymers may have a polymerizable functional group at the terminal or main chain.

(6) alkyl (meth) acrylate, alkylene bis (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Polymerized acrylic monomers such as dipentaerythritol hexa (meth) acrylate. Polymerizable monomers such as alkylene bisglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, pentaerythritol tetraglycidyl ether, vinylcyclohexene diepoxide. Here, (meth) acrylate refers to both acrylate and methacrylate. These are polymers.

(7) Curable resin. For example, (meth) acrylic UV curable resin, moisture curable silicone resin, thermosetting silicone resin, epoxy resin, phenoxy resin, novolac resin, silicone acrylate resin, melamine resin, phenol resin, unsaturated polyester resin , Polyimide resin, urethane resin, urea resin and the like.
(8) The alkyl groups and hydrogen groups in the above (1) to (7) can be substituted with fluorine. Those substituted with fluorine have a low refractive index and excellent optical performance. However, since it may be mechanically weak alone, it can be used by mixing with inorganic fine particles.

The binder may be used alone or in combination. In particular, a reactive silane compound having both a polymerizable functional group and a functional group capable of forming a covalent bond with a silica particle in the same molecule listed in (2), a polymerizable monomer listed in (6), or The combined use of the fluorine-substituted products (2) and (6) is effective in improving the mechanical strength.
The kind of the polymerizable monomer is appropriately selected according to the form and speed of the reaction. When using a polymerizable monomer or one having a functional group, it is effective to add a polymerization initiator as an additive. As the polymerization initiator, a known one such as a thermal radical generator, a photo radical generator, a thermal acid generator, or a photo acid generator can be selected according to the reaction mode of the above polymerizable functional group or polymerizable monomer. it can.

  Specific examples of the heat / photo radical generator include Irgacure (registered trademark) and Darocur (registered trademark) acetophenone-based, benzophenone-based, phosphine oxide-based, and titanocene-based commercially available from Ciba Specialty Chemicals Co., Ltd. Each polymerization initiator, a thioxanthone polymerization initiator, a diazo polymerization initiator, an o-acyloxime polymerization initiator, and the like can be mentioned. Among these, polymerization initiators having an amino group and / or a morpholino group in the molecule such as Irgacure (registered trademark) 907, Irgacure (registered trademark) 369, and Irgacure (registered trademark) 379 are particularly preferable. Specific examples of the heat / photoacid generator include Sun Aid (trademark) SI series commercially available from Sanshin Chemical Industry Co., Ltd., WPI series, WPAG series, and Sigma Aldrich commercially available from Wako Pure Chemical Industries, Ltd. Examples thereof include sulfonium-based, iodonium-based, and diazomethane-based polymerization initiators represented by the PAGs series commercially available from Japan Corporation.

The silanes represented by (1) and (2) are preferably used after partial hydrolysis / dehydration condensation. Partial hydrolysis and dehydration condensation reactions are carried out by reacting hydrolyzable silane with water, but as catalysts, acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, formic acid, acetic acid, ammonia, trialkylamine Alkalis such as sodium hydroxide, potassium hydroxide, choline and tetraalkylammonium hydroxide, and tin compounds such as dibutyltin dilaurate may be used. In that case, the hydrolysis / dehydration condensation reaction may be performed in the presence of silica fine particles or hollow silica fine particles.
From the viewpoint of the surface shape of the low refractive index layer, the mechanical strength, and the antireflection performance, the amount of the binder is 0.5 or more and 5.0 by weight ratio when the combined weight of the silica fine particles and the hollow silica fine particles is 1. The following is preferred.
The binder itself preferably has a refractive index of 1.3 to 1.55. By using a material having a relatively low refractive index, a low refractive index layer having a very low refractive index can be obtained.

The antiglare antireflection film in the present invention includes various additives such as an antistatic agent, an ultraviolet absorber, an infrared absorber, a leveling agent, a dye, a metal salt, a surfactant, and a release agent. It is also possible to contain in the range which does not impair.
The thickness of the low refractive index layer is 50 to 300 nm, but from the viewpoint of antireflection performance in the visible light region, it is usually preferable that the minimum reflectance wavelength at an incident angle of 5 degrees is in the range of 500 to 750 nm. . FIG. 2 shows an example of a reflectance spectrum at an incident angle of 5 degrees of the antiglare antireflection film of the present invention. For the refractive index of the low refractive index layer, it is important to control the amount of silica fine particles, the amount of hollow silica fine particles, and the amount of binder so that the minimum reflectance at an incident angle of 5 degrees is 2% or less. Thereby, the reflection of external light can be significantly reduced by a synergistic effect with the anti-glare property.

In the present invention, the surface of silica fine particles or hollow silica fine particles is preferably treated with a reactive silane compound. A reactive silane compound is a compound having both a polymerizable functional group and a functional group capable of forming a covalent bond with a silica particle in the same molecule. Since the surface of the hollow silica fine particles and the reactive silane compound are covalently bonded and a reaction with the binder occurs, the adhesion between the silica fine particles or the hollow silica fine particles and the binder can be improved. Moreover, since the surface slipperiness of silica fine particles or hollow silica fine particles can be improved, a low refractive index layer having high pencil hardness can be obtained. The polymerizable functional group is not particularly limited, and examples thereof include an unsaturated double bond such as a vinyl group, an acryl group, and a methacryl group, an epoxy group, and a hydroxyl group. .
The reactive silane compound having both a polymerizable functional group and a functional group capable of forming a covalent bond in the same molecule can also be used as a binder for an antiglare antireflection layer (2) Alternatively, those in which these alkyl groups or hydrogen groups are substituted with fluorine can be used. Specific examples include the following.

  For example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3 -Methacryloxypropyltriethoxysilane, 3-acryloxypropyltriacetoxysilane, 3-acryloxypropyltris (trichloroacetoxy) silane, 3-acryloxypropyltris (trifluoroacetoxy) silane, 3-methacryloxypropyltriacetoxysilane 3-methacryloxypropyltris (trichloroacetoxy) silane, 3-methacryloxypropyltris (trifluoroacetoxy) silane, 3-glycidoxypropyltriacetoxy 3-glycidoxypropyltris (trichloroacetoxy) silane, 3-glycidoxypropyltris (trifluoroacetoxy) silane, 3-acryloxypropyltrichlorosilane, 3-acryloxypropyltribromosilane, 3-acryloxy Propyltrifluorosilane, 3-methacryloxypropyltrichlorosilane, 3-methacryloxypropyltribromosilane, 3-methacryloxypropyltrifluorosilane, 3-glycidoxypropyltrichlorosilane, 3-glycidoxypropyltribromosilane , Compounds such as 3-glycidoxypropyl trifluorosilane, those in which these alkyl groups and hydrogen groups are substituted with fluorine, and those obtained by reaction thereof.

  As a method for treating the surface of silica fine particles or hollow silica fine particles with a reactive silane compound, it is preferable to use a functional group that forms a covalent bond with the silica particles of the reactive silane compound by partial hydrolysis and dehydration condensation. Partial hydrolysis and dehydration condensation reactions are carried out by reacting hydrolyzable silane with water, but as catalysts, acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, formic acid, acetic acid, ammonia, trialkylamine Alkalis such as sodium hydroxide, potassium hydroxide, choline and tetraalkylammonium hydroxide, and tin compounds such as dibutyltin dilaurate may be used.

The surface of silica fine particles or hollow silica fine particles often has 0.1 to 100 OH groups per 1 nm ² , and ^1/2 of the surface of silica fine particles or hollow silica fine particles in the treatment with a reactive silane compound. It is a preferred embodiment that 20 or more OH group-corresponding portions are reacted with the reactive silane compound, and further, a treatment in combination with fluoroalkyl (trialkoxy) silane is also a preferred embodiment. The treatment with fluoroalkyl (trialkoxy) silane may be performed in the presence of silica fine particles, hollow silica fine particles and a reactive silane compound, or may be performed separately.

As fluoroalkyl (trialkoxy) silane, for example,
_{CF 3 (CF 2) xCH 2} CH 2 Si (OR) 3
R: an alkyl group such as —CH ₃ , —C ₂ H ₅ , and —isopropyl group x: an integer of 1 to 10 can be used. In the treatment with the fluoroalkyl (trialkoxy) silane, it is preferable to react and bond more than 1/20 or more of the surface of the silica fine particles or hollow silica fine particles corresponding to the OH group. This can further improve the wear resistance of the antiglare antireflection layer, improve the antifouling property of the surface, and improve the wiping property of fingerprints.
From the viewpoint of reactivity of fluoroalkyl (trialkoxy) silane with silica fine particles and hollow silica fine particles, R: —CH ₃ is preferable, and x is preferably 3 to 7.

As a method of reacting a reactive silane compound and fluoroalkyl (trialkoxy) silane with silica fine particles or hollow silica fine particles, a reactive silane compound and fluoroalkyl (trialkoxy) silane are dispersed in a dispersion of silica fine particles or hollow silica fine particles. As a catalyst, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, formic acid, acetic acid and other acids, ammonia, trialkylamine, sodium hydroxide, potassium hydroxide, choline, tetraalkylammonium hydroxide, etc. The reaction can be carried out by adding a tin compound such as dibutyltin dilaurate and adjusting the appropriate temperature and time. In addition, by setting the total number of moles of the reactive silane compound and fluoroalkyl (trialkoxy) silane to be approximately equivalent to the total amount of surface OH groups, the silica particles of the reactive silane compound and fluoroalkyl (trialkoxy) silane It is possible to correspond to the quantity ratio on the surface of the hollow silica fine particles. The ratio of the reactive silane compound and the fluoroalkyl (trialkoxy) silane is preferably used in a weight ratio of 10: 1 to 1:10.
The low refractive index layer of the present invention can contain various additives such as an antistatic agent, an ultraviolet absorber, an infrared absorber, a leveling agent, a dye, a metal salt, a surfactant, and a release agent.
The low refractive index layer of the present invention can be obtained, for example, by applying and curing on a substrate in a state where silica fine particles, a binder, an additive and the like are dispersed in an appropriate dispersion medium. The dispersion medium to be used is not limited as long as silica fine particles, binders, additives and the like are substantially stably dispersed.

Specific examples of the dispersion medium include water, monohydric alcohols having 1 to 6 carbon atoms, dihydric alcohols having 1 to 6 carbon atoms, alcohols such as glycerin, formamide, N-methylformamide, N-ethylformamide, N , N-dimethylformamide, N, N-diethylformamide, N-methylacetamide, N-ethylacetamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone and other amides, tetrahydrofuran, diethyl ether , Ethers such as di (n-propyl) ether, diisopropyl ether, diglyme, 1,4-dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, ethylene glycol monomethyl ether Teranol, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether and other alkanol ethers, ethyl formate, acetic acid Methyl, ethyl acetate, ethyl lactate, ethylene glycol monomethyl ether acetate, ethylene glycol diacetate, propylene glycol monomethyl ether acetate, diethyl carbonate, ethylene carbonate, propylene carbonate, γ-butyrolactone, ethyl acetoacetate esters, acetone, methyl ethyl ketone, Methyl propyl ketone, methyl (n-butyl) ketone , Ketones such as methyl isobutyl ketone, methyl amyl ketone, acetylacetone, cyclopentanone and cyclohexanone, nitriles such as acetonitrile, propionitrile, n-butyronitrile and isobutyronitrile, dimethyl sulfoxide, dimethyl sulfone and sulfolane are suitable. Used for.

More preferable dispersion media are monohydric alcohols having 1 to 6 carbon atoms, and ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol monopropyl Ethers, alkanol ethers such as ethylene glycol monobutyl ether, propylene glycol monobutyl ether, acetone, methyl ethyl ketone, methyl propyl ketone, methyl (n-butyl) ketone, methyl isobutyl ketone, methyl amyl ketone, acetylacetone, cyclopentanone, cyclohexanone, etc. Ketones.
These dispersion media may be mixed or any other solvent or additive may be mixed as long as the object of the present invention is not impaired.

In applying the above dispersion to a substrate, it is also effective to add a known leveling agent or a binding aid (coupling agent) in order to increase the coating performance and the adhesion to the substrate.
The method for producing the low refractive index layer is, when applied using a coating composition, the content of inorganic particles such as silica fine particles, the concentration of the coating liquid, the types of binders and additives and their concentrations, the coating method, and the coating. It can be manufactured by controlling conditions and the like.
The concentration of the coating solution is, for example, 0.1 to 20 parts by weight as a reactive silane compound and 0.1 to 20 parts by weight of fluoroalkyl (trialkoxy) silane when the solid content of the hollow silica fine particles is 100 parts by weight. It is a preferable embodiment to adjust the content of the binder and the binder component in the range of 50 to 500 parts by weight.

  Application of the coating composition is a known dipping, spin coater, knife coater, bar coater, blade coater, squeeze coater, reverse roll coater, gravure roll coater, slide coater, curtain coater, spray coater, die coater, cap coater, etc. It can be implemented using a method. Of these, knife coaters, bar coaters, blade coaters, squeeze coaters, reverse roll coaters, gravure roll coaters, slide coaters, curtain coaters, spray coaters, die coaters and cap coaters that can be continuously applied are preferably used.

The environmental humidity during application is preferably 40% or more and 99% or less, particularly 45% or more and 95% or less. By setting the humidity to 40% or more, the condensed water generated on the coating film diffuses into the film due to the heat of vaporization caused by evaporation of the dispersion medium. A droplet-like structure can be formed by the interaction between the condensed water and the composition constituting the low refractive index layer, and the surface shape of the present invention can be formed. This droplet-like structure can also be controlled by the type of dispersion medium of the coating composition used and the environmental humidity.
After applying the above coating composition, it is effective to heat in order to volatilize the dispersion medium and to condense and crosslink the reactive silane compound and binder component. The heating temperature and time are determined by the heat resistance of the substrate. For example, when a transparent plastic film is used, the heating temperature is selected from 50 ° C. to 200 ° C., and the time is selected from 1 second to 1 hour, preferably 80 ° C. to 150 ° C., and 10 seconds to 3 minutes. Moreover, when the said binder has radiation curability, an ultraviolet-ray, an electron beam, etc. are irradiated by a well-known method.

Next, the hard coat layer will be described.
In the antiglare antireflection film of the present invention, a hard coat layer can be provided between the transparent film and the low refractive index layer. By providing the hard coat layer, the surface layer of a display or the like can be strengthened and the surface can be hardly damaged. As the hard coat layer, those having a pencil strength of H or higher in the pencil hardness test according to JIS K5400 are preferably used, and those of 2H or higher are more preferable. On the other hand, from the viewpoint of dust adhesion on the display surface, the surface resistivity is preferably 10 ¹⁶ Ω / □ or less, and more preferably 10 ¹⁴ Ω / □ or less.

The refractive index of the hard coat layer is preferable because the occurrence of interference fringes can be suppressed by making the difference from the refractive index of the transparent film used 0.001 or more and 0.05 or less. That is, by suppressing reflection from the interface between the optical base material and the antistatic hard coat layer, the amplitude of the reflection spectrum in the visible light region can be reduced, and the occurrence of interference fringes can be suppressed.
In order to satisfy all of pencil hardness, surface resistance, and prevention of interference fringes as the hard coat layer, it is preferable to use an antistatic hard coat. The surface resistivity is preferably 10 ³ to 10 ¹⁶ Ω / □ from the viewpoint of the refractive index.

For example, when a TAC film having a refractive index of 1.49 is used to form a TAC film / hard coat layer / low refractive index layer, the refractive index of the hard coat layer is from the viewpoint of reflectance and interference fringe prevention. It is preferable to set it to 1.44-1.54. In the case of this configuration, it is preferable to provide an antistatic function in the hard coat layer. By mixing conductive fine particles and inorganic particles having a low refractive index, the antistatic function and the refractive index can be adjusted, and the pencil hardness can be set to H or higher.
As a representative material of the hard coat layer, melamine type, acrylic radical type, acrylic silicone type, alkoxysilane type are preferable, and organic and / or inorganic fine particles dispersed using these hard coat materials as a matrix (hereinafter referred to as “the hard coat layer”). It is also possible to use an organic / inorganic particle dispersion system).

Among the above hard coat materials, the acrylic radical system is preferably a polymer obtained by polymerizing a polyfunctional acrylate oligomer and / or a polyfunctional acrylate monomer. Examples of the polyfunctional acrylate monomer include dipentaerythritol hexaacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and ditrimethylolpropane tetraacrylate.
Polyfunctional acrylate oligomers include epoxy acrylates that are acrylate-modified novolak-type and bisphenol-type epoxy resins, urethane acrylates that are acrylate-modified products of urethane compounds obtained by reacting polyisocyanates and polyols, and polyester acrylates that are acrylate-modified polyester resins. Etc.

In the acrylic silicone type, those in which an acrylic group is covalently bonded to a silicone resin are preferable.
Moreover, in the alkoxysilane type | system | group, what contains the condensate which has the silanol group obtained by carrying out the hydrolysis polycondensation of alkoxysilane is preferable. A silanol group is converted into a siloxane bond by thermosetting after coating, and a cured film is obtained.
The hard coat layer is preferably a hard coat material capable of performing heat curing, ultraviolet curing, and electron beam curing. The hard coat material preferably contains a photopolymerization initiator, a thermal polymerization initiator, an additive, a solvent and the like depending on the curing method.

Examples of inorganic particles used in the above organic / inorganic particle dispersion include silicon dioxide particles, titanium dioxide particles, aluminum oxide particles, zirconium oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc, kaolin and sulfuric acid. A calcium particle is mentioned. Examples of organic particles include methacrylic acid-methyl acrylate copolymer, silicone resin, polystyrene, polycarbonate, acrylic acid-styrene copolymer, benzoguanamine resin, melamine resin, polyolefin, polyester, polyamide, polyimide, and polyfluorinated ethylene. The average particle diameter of these particles is preferably 0.01 to 5 μm, and more preferably 0.01 to 0.3 μm. A plurality of organic particles and inorganic particles may be mixed and used, or a mixture of organic particles and inorganic particles may be used.

The organic particles and inorganic particles that can be used in the present invention may or may not be chemically bonded to the hard coat material used as a matrix. The organic / inorganic particle-dispersed hard coat material has a function of increasing the hardness of the hard coat layer and suppressing curing shrinkage by dispersing the particles in the hard coat material.
Specific examples of the inorganic particle dispersion system include an acrylic radical system in which inorganic fine particles are dispersed, an organic polymer system in which inorganic fine particles are dispersed, an organoalkoxysilane system in which inorganic fine particles are dispersed, and the like. What disperse | distributed silica, titanium oxide, an alumina, etc. is preferable. Further, it is also preferable to use fine particles in which the surface of the silica particles is modified with an acryloyl group or the like.
In addition to the hard coat layer, colorants (pigments, dyes), antifoaming agents, thickeners, leveling agents, flame retardants, UV absorbers, antistatic agents, antioxidants and modifying resins are added. Also good.

As the antistatic agent for imparting antistatic properties, a known antistatic agent such as a surfactant or an ionic polymer, or conductive fine particles dispersed in a binder is used. Examples of the conductive fine particles include oxide or composite oxide fine particles such as indium, zinc, tin, molybdenum, antimony, and gallium, copper, silver, nickel, low melting point alloy (solder, etc.) metal fine particles, and a metal-coated polymer. Known materials such as fine particles, various kinds of carbon black, conductive polymer particles such as polypyrrole and polyaniline, metal fibers, and carbon fibers can be used. Among these, ITO (tin-containing indium oxide) particles, ATO (tin-containing antimony oxide) particles, and antimony pentoxide particles are particularly preferable because they can exhibit high transparency and conductivity. Further, in order to prevent interference fringes, when conductive fine particles are used, it is used in combination with low refractive index inorganic particles having a refractive index of 1.50 or less such as silica particles. It can be made 05 or less. Moreover, since the inorganic particles are used, the pencil hardness can be improved. A combination of silica particles and antimony pentoxide particles is a preferred embodiment.
It is also preferable when the hard coat layer is surface-modified. Surface modification treatment is preferably corona treatment, deep-UV irradiation, excimer lamp irradiation, vacuum plasma treatment, atmospheric pressure plasma treatment, electron beam irradiation, primer treatment containing a silane coupling agent, etc. In particular, the corona treatment is preferably used industrially.

For coating the hard coat layer, a composition obtained by adding additives as necessary to the above hard coat material is applied on a transparent plastic substrate as a coating solution using a solvent as necessary, and is formed and cured. Can be manufactured. Solvents include water, methanol, ethanol, isopropanol, butanol, benzyl alcohol and other alcohols, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and other ketones, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, Esters such as ethyl formate, propyl formate and butyl formate, aliphatic hydrocarbons such as hexane and cyclohexane, halogenated hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride, and aromatic carbonization such as benzene, toluene and xylene Hydrogens, amides such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, diethyl ether, dioxane, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol dimethyl Ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, solvent ethers such as propylene glycol dimethyl ether, preferably toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol.

The hard coat layer can be obtained by coating and drying and then heating and curing at 80 to 150 ° C. or curing using light or an electron beam.
The hard coat material that can be used in the present invention has been described above, but as the hard coat material that can be used in the present invention, a commercially available silicone hard coat, (meth) acrylic hard coat, epoxy hard coat, Known materials such as urethane hard coat, epoxy acrylate hard coat, and urethane acrylate hard coat can be used. Specifically, Shin-Etsu Chemical Co., Ltd. UV curable silicone hard coat agent X-12 series, GE Toshiba Silicone Co., Ltd. UV curable silicone hard coat agent UVHC series, thermosetting silicone hard coat agent SHC series, stock A thermosetting silicone hard coat agent Solguard NP series manufactured by Nippon Dacro Shamrock Co., Ltd. and a UV curable hard coat agent KAYANOVA FOP series manufactured by Nippon Kayaku Co., Ltd. are preferred. In addition, it can be formed by applying a coating liquid containing a polyfunctional monomer and a polymerization initiator and polymerizing the polyfunctional monomer. The thickness of the hard coat layer is usually set to 0.1 μm to 10 μm.

  Application of the coating composition is a known dipping, spin coater, knife coater, bar coater, blade coater, squeeze coater, reverse roll coater, gravure roll coater, slide coater, curtain coater, spray coater, die coater, cap coater, etc. It can be implemented using a method. Of these, knife coaters, bar coaters, blade coaters, squeeze coaters, reverse roll coaters, gravure roll coaters, slide coaters, curtain coaters, spray coaters, die coaters and cap coaters that can be continuously applied are preferably used.

  The antiglare antireflection film of the present invention may have a configuration of transparent film / hard coat layer / high refractive index layer / low refractive index layer. In the case of this configuration, an antistatic function can be imparted to the high refractive index layer. As the high refractive index layer, for example, known inorganic fine particles such as oxides or composite oxides made of metals such as titanium, zirconium, zinc, antimony, indium, tin, cerium, tantalum, yttrium, hafnium, aluminum, and magnesium, Those dispersed in a binder are used. As the binder, those listed in the above (1) to (8) can be used as the binder of the low refractive index layer, but among them, the organic polymer described in (5) is preferably polymerized on the side chain or terminal. A polymerizable monomer described in (6), and a curable resin described in (7). As the kind and amount of these binders, known binders can be used depending on the desired refractive index, strength, light resistance, yellowing and the like. The refractive index of the high refractive index layer is preferably 1.55 to 1.68 in terms of antireflection performance, and particularly preferably 1.57 to 1.65. The thickness of the high refractive index layer is preferably 50 to 300 nm, particularly preferably 120 to 180 nm. By controlling the thickness, it is possible to control the reflectance and the color of the antireflection film.

  The antiglare antireflection film of the present invention may be provided with a coating layer in order to impart slipperiness or antifouling property to the surface. The coating layer is, for example, a fluororesin, a moisture curable silicone resin, a thermosetting silicone resin, silicon dioxide, a (meth) acrylic resin, a (meth) acrylic UV curable resin, an epoxy resin, a phenoxy resin, a novolac resin, It is made of any known material such as silicone acrylate resin, melamine resin, phenol resin, unsaturated polyester resin, polyimide resin, urethane resin, urea resin. The film thickness of the coating layer is usually 50 nm or less, preferably 10 nm or less. The coating layer may be composed of a single layer or a plurality of layers. Among these, a fluororesin, a moisture curable silicone resin, and a thermosetting silicone resin are preferable in order to exhibit an antifouling effect.

Although the manufacturing method of the anti-glare antireflection film of the present invention is not limited, the anti-glare antireflection film may be manufactured via a transfer foil.
The antiglare antireflection film of the present invention preferably has a natural color as the reflection color. When the chromaticity coordinates x and y (JIS Z 8722-2000) of the XYZ color system based on the double field of view are used as the reflection color expression, x = 0.22 to 0.42 as an antiglare antireflection film, A range of y = 0.20 to 0.42 is preferable, and x = 0.23 to 0.39 and y = 0.23 to 0.39 are particularly preferable. Since the reflectance is low and it has such a natural reflection color, when the antiglare antireflection film of the present invention is used on the display surface, the color of transmitted light becomes natural and the reflection of external light Since there is no coloring due to, color display with excellent color reproducibility is possible in any state.

  The antiglare antireflection film of the present invention preferably has a haze value of 3.0% or less. In particular, those of 0.01% or more and 2.0% or less are preferably used. When the haze value is very small as described above, the transmitted image of the PDP is clear and it is easy to obtain a clear and high contrast image. In the present invention, since the reflection of external light is controlled by the surface shape of the very thin low refractive index layer, it is easy to reduce the haze and easily maintain the clearness of the transmitted image of the PDP. be able to.

The antiglare antireflection film of the present invention is capable of observing silica fine particles by preparing a thin film slice of the cross section and taking a cross-sectional photograph with a transmission electron microscope. When hollow silica fine particles are used, the vicinity of the center of the particles is hollow, so it looks bright in the photograph.
As a preferred embodiment of the present invention, an embodiment in which a TAC film is used as a transparent film and an antistatic hard coat layer, silica fine particles or / and hollow silica fine particles and a low refractive index layer containing a binder are sequentially laminated thereon is preferably used. . Such a laminate can also be bonded to a member such as glass via an adhesive or a thermoplastic resin.

The anti-glare antireflection film of the present invention can be preferably used particularly on the outermost surface of an optical filter of PDP, but in addition, for example, eyeglass field such as eyeglass lenses, goggles, contact lenses; car windows, instrument panels, navigation Automotive fields such as systems; Housing and architectural fields such as window glass; Agricultural fields such as light-transmitting films and sheets of houses; Energy fields such as solar cells, photovoltaic cells and lasers; TV cathode ray tubes, notebook computers, electronic notebooks, touch panels, Liquid crystal television, liquid crystal display, in-vehicle television, liquid crystal video, projection television, plasma addressed liquid crystal display, field emission display, organic / inorganic EL display, light emitting diode display, optical fiber, optical disc, etc .; Household goods such as lights, mirrors and watches; business cases such as showcases, foreheads, semiconductor lithography and copy machines; prevention of reflections and / or entertainment in liquid crystal game machines, pachinko machine glass, game machines and other entertainment fields Or it can be used for a very wide range of applications that require improved light transmission.
Hereinafter, examples will be described in order to further clarify the present invention.

[Various measurement methods]
-Minimum reflectance and minimum reflectance wavelength at an incident angle of 5 degrees;
An antiglare antireflection film consisting of a transparent film / hard coat layer / low refractive index layer is attached to a glass plate (NA Techno Glass, NA35, 0.70 mm, for TFT) with an acrylic optical adhesive, and the glass plate In order to cut off the reflected light on the back surface (surface without the low refractive index layer), the back surface was roughed with sandpaper and then painted with black ink. Then, using a spectrophotometer UV-2450 / MPC2200 type 5 ° absolute reflectance measuring device (manufactured by Shimadzu Corporation), the reflectance spectrum in the wavelength range of 300 nm to 800 nm is measured at 0.5 nm intervals, and the lowest The reflectance was defined as the minimum reflectance, and the wavelength at that time was defined as the minimum reflectance wavelength (see FIG. 2).
For the visibility reflectance, the visibility reflectance for the D65 light source defined in JIS Z8720 was calculated from the measured reflectance spectrum.
Further, from the measured reflectance spectrum, chromaticity coordinates xy of the XYZ color system defined in JIS Z8722 as a reflected color were calculated.

-Transmission image sharpness: JIS using a image clarity measuring device ICM-1T manufactured by Suga Test Instruments Co., Ltd.
Measurement was performed in accordance with K7105, and the total value of transmitted image clarity in the four types of optical combs was defined as the sum of transmitted image clarity.
-45 degree reflection image sharpness: Antiglare property consisting of transparent film / hard coat layer / low refractive index layer with acrylic optical adhesive on glass plate (NA Techno Glass, NA35, 0.70mmt, for TFT) An antireflection film was attached, and the back surface of the glass plate (surface without the low refractive index layer) was cut with a black ink after roughening the back surface with sandpaper. Then, using Suga Test Instruments Co., Ltd. image clarity measuring device ICM-1T, it measured based on JIS K7105, and the 45 degree reflected image definition of the 45 degree reflected image sharpness in four types of optical combs was carried out. The sum of

Center line average roughness (Ra): A glass plate (NA Techno Glass, NA35, 0.70 mmt, for TFT) with acrylic optical adhesive, and a transparent film / hard coat layer / low refractive index layer A dazzling antireflection film was applied, and measurement was performed in accordance with JIS B0601 using a high-accuracy fine shape measuring device Surfcoder ET4000 manufactured by Kosaka Laboratory. Note that the reference length conforms to JIS B0633.
Average slope gradient (Δa): Glass plate (NA Techno Glass, NA35, 0.70mmt, for TFT) with acrylic optical adhesive, antiglare consisting of transparent film / hard coat layer / low refractive index layer An antireflection film was applied, and measurement was performed in accordance with ASME B46.1: 1995 using a high-accuracy fine shape measuring device Surfcoder ET4000 manufactured by Kosaka Laboratory.

Pencil hardness: Using a test pencil specified in JIS S6006, the pencil hardness at a load of 500 g was evaluated according to the pencil hardness evaluation method specified in JIS K5400.
(7) Method for estimating the refractive index of powder: A small amount of powder is placed on a slide glass, and a few drops of a liquid having a known refractive index are dropped into this and mixed with the powder. When the mixed liquid became transparent in this state, the known liquid and the powder were considered to have the same refractive index.
(8) Measurement of total light transmittance and haze: Using a turbidimeter (cloudiness meter) NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd., it was measured by the method defined in JIS K7361-1.
(9) PDP transmission image sharpness: An antiglare antireflection film was attached to a front plate filter of a PDP display device having a front filter using an adhesive LS0280 (manufactured by Lintec Corporation) on the outer surface. Then, an image was displayed on the PDP display device, and the clarity of the transmitted image was visually determined according to the following criteria.
○ ・ ・ ・ Transparent image is sharpness × ・ ・ ・ Transparent image is blurred and unclear

(10) Anti-glare property of PDP: An anti-glare antireflection film was attached to the outer surface of a front plate filter of a PDP display device having a front filter using an adhesive LS0280 (manufactured by Lintec Corporation). The light of the fluorescent lamp emitting light on the side on which the antiglare antireflection film was formed was directly reflected, and the image of the reflected fluorescent lamp image was visually determined according to the following criteria.
○ ・ ・ ・ The image of the fluorescent light is blurred.
Δ: The image of the fluorescent lamp is slightly blurred.
X: The image of the fluorescent lamp can be clearly recognized.

[Adjustment of coating solution]
(Hard coat layer coating solution HC-A)
MIBK-ST (manufactured by Nissan Chemical Industries, Ltd., SiO ₂ , particle size of 10 to 15 nm) with respect to 100 parts by weight of UV curable hard coat paint P-4560 (manufactured by Catalyst Kasei Kogyo Co., Ltd., Sb ₂ O ₅ + UV resin) , 30 wt% MIBK dispersion) was mixed to prepare hard coat layer coating solution HC-A.
When this hard coat coating solution HC-A was applied to an acrylic plate having a known refractive index, dried and UV cured, the refractive index was examined.

(Hard coat layer coating solution HC-B)
100 parts by weight of urethane acrylate (Unidic 17-806, manufactured by Dainippon Ink & Chemicals, Inc.) and 86 parts by weight of 5.85 wt% Irgacure 907 / toluene solution were mixed, and then a fluorine leveling agent (Dainippon Ink and Chemicals, Inc.) 0.5 part by weight, manufactured by Co., Ltd., MegaFuck F470) was added and mixed. Next, 7 parts by weight of acrylic beads (manufactured by Soken Chemical Co., Ltd., cross-linked acrylic monodispersed particles, MX-300, average particle diameter 3 μm), and styrene beads (manufactured by Soken Chemical Co., Ltd., cross-linked polystyrene monodispersed particles, SX-350H, 7 parts by weight of an average particle size of 3.5 μm was added and ultrasonically dispersed to prepare a hard coat layer coating solution HC-B.

(Low refractive index layer coating liquid LA)
As the hollow silica fine particles, an isopropanol (hereinafter referred to as IPA) dispersion having an average particle diameter of 100 nm, a refractive index of 1.20, and a solid content of 20 wt% was used as a hollow silica fine particle. When the hollow silica fine particles were observed with a transmission electron microscope, the wall thickness was about 9 nm. The hollow silica fine particle IPA dispersion was diluted with IPA to prepare a hollow silica / IPA dispersion having a solid content of 8.16 wt%. To 100 parts by weight of this hollow silica / IPA dispersion, 13.5 parts by weight of 3-methacryloxypropyltrimethoxysilane as a reactive silane compound was added dropwise with stirring. Then, 5.6 parts by weight of 0.1N aqueous nitric acid solution was added dropwise with stirring, and then hydrolyzed at room temperature for 4 hours. Thereafter, 875 parts by weight of 0.23 wt% Irgacure 369 / ethanol solution was added with stirring to obtain a low refractive index layer coating solution LA having a solid content of 2 wt%.

(Low refractive index layer coating liquid LB)
To 100 parts by weight of low refractive index layer coating liquid LA, 0.2 part by weight of a methacryl-modified silicone compound (X-22-2404 manufactured by Shin-Etsu Silicone Co., Ltd.) was added with stirring, and the low refractive index layer It was set as coating liquid LB.
(Low refractive index coating liquid LC)
Low-refractive index coating liquid L-, except that an isopropanol (hereinafter referred to as IPA) dispersion having a mean particle size of 60 nm, a refractive index of 1.30, and a solid content of 20 wt% was used as hollow silica fine particles. In the same manner as A, a low refractive index coating liquid LC was prepared.

(Low refractive index coating liquid LD)
As the hollow silica fine particles, an isopropanol (hereinafter referred to as IPA) dispersion having an average particle diameter of 60 nm, a refractive index of 1.30, and a solid content of 20 wt% was used as the hollow silica fine particles. The hollow silica fine particle IPA dispersion was diluted with IPA to prepare a hollow silica / IPA dispersion having a solid content of 8.16 wt%. To 100 parts by weight of this hollow silica / IPA dispersion, 5 parts by weight of 3-methacryloxypropyltrimethoxysilane as a reactive silane compound was added dropwise with stirring. Subsequently, 2 parts by weight of a 0.1N aqueous nitric acid solution was added dropwise with stirring, followed by hydrolysis at room temperature for 4 hours. Thereafter, 518 parts by weight of 0.14 wt% Irgacure 369 / ethanol solution was added with stirring, and the low refractive index layer coating liquid L- with a solid content of 2 wt% was added.
D.
(Low refractive index coating liquid LE)
100 parts by weight of a fluorine-based low-refractive material (manufactured by JSR Corporation, Opstar TU2085, solid content 10.5 wt%) is diluted with 425 parts by weight of propylene glycol monomethyl ether acetate / t-butanol = 25/75 (weight ratio) to obtain a solid A low refractive index coating liquid LE with a content of 2 wt% was prepared.

[Example 1]
(Formation of hard coat layer)
As an optical substrate (transparent film), a TAC film (thickness 80 μm) TDY80UL containing a UV absorber manufactured by Fuji Photo Film Co., Ltd. was used, and the “hard coat layer coating solution HC-A” was dried using a bar coater. Coating was performed so that the subsequent thickness was 1.8 to 2.0 μm. After drying the film after coating with a bar coater at 80 ° C. for 1 minute, using a UV exposure apparatus (H bulb) manufactured by Fusion UV Systems Japan Co., Ltd., with an illuminance of 2600 mW / cm ² and a light intensity of 750 mJ / cm ² Hardened to form a hard coat layer.

(Formation of a low refractive index layer)
The “low refractive index layer coating solution LA” was applied to the transparent film with a hard coat layer using a bar coater under an atmosphere of 65 RH%. After the film after a bar coater coating was dried for 1 minute at 120 ° C., using a Fusion UV Systems Japan Ltd. UV exposure apparatus (H bulb), illumination 2600mW / cm ^2, curing light quantity 1500 mJ / cm ² Thus, a low refractive index layer (thickness: 110 nm) was formed to obtain an antiglare antireflection film.
(Evaluation of antiglare antireflection film)
The obtained antiglare antireflection film was evaluated by the methods described in “Various measurement methods”. The results from this evaluation method are summarized in Table 1.

[Examples 2-3, Comparative Examples 1-2]
The hard coat layer and the low refractive index layer were formed in the same manner as in Example 1 except for the coating liquid to be used. As the transparent film, a TAC film was used in the same manner as in Example 1.
The obtained antiglare antireflection film was evaluated in the same manner as in Example 1, and the results are summarized in Table 1.

[Comparative Example 3]
The hard coat layer was formed in the same manner as in Example 1 except for the coating solution to be used. The low refractive index layer was formed by applying “low refractive index layer coating solution LE” to a transparent film with a hard coat using a bar coater. Then, after drying at 80 ° C. for 3 minutes, using a UV exposure apparatus (H bulb) manufactured by Fusion UV Systems Japan Co., Ltd., it is cured at an oxygen concentration of 100 ppm or less, an illuminance of 2600 mW / cm ² , and a light intensity of 1500 mJ / cm ^2. Thus, a low refractive index layer was formed to obtain an antiglare antireflection film.
The obtained antiglare antireflection film was evaluated in the same manner as in Example 1, and the results are summarized in Table 1.

  The antiglare antireflection film of the present invention is excellent in transmitted image definition and antiglare properties, and is expected to be used as an antiglare antireflection film for PDPs.

Surface shape height difference differential image of droplet-like structure Reflectance spectrum of an antiglare antireflection film at an incident angle of 5 degrees

Explanation of symbols

a: Droplet diameter (μm) of the droplet-like structure
b: Distance between centers of droplets having a droplet-like structure (μm)
R: reflectance λ: wavelength

Claims (4)

  In the antiglare antireflection film in which a low refractive index layer having a refractive index lower than the refractive index of the transparent film is provided on at least one surface of the transparent film, the low refractive index layer has a centerline average roughness Ra. Is an antiglare antireflection film characterized by having an average inclination gradient Δa of 0.005 to 0.05 rad and a surface shape having a droplet-like structure.   2. The antiglare antireflection film according to claim 1, wherein the droplets having a droplet-like structure have an average diameter of 1 to 150 μm and an average distance between the droplet centers of 5 to 300 μm.   The antiglare antireflection film according to claim 1 or 2, wherein the low refractive index layer contains silica fine particles and a binder, and the average particle size of the silica fine particles is 3 to 200 nm.   The thickness of the low refractive index layer is 50 to 300 nm, the minimum reflectance at an incident angle of 5 degrees is 2% or less, and the minimum reflectance wavelength is in the range of 500 to 750 nm. The anti-glare antireflection film according to any one of the above.

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