JP2000275401A - Antireflection film and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection film having anti-reflection and -glare functions equal to that composed of an evaporation layer, even if it contains a low refractive index layer as an application layer. SOLUTION: In an antireflection coating formed of a laminate of a transparent base material 13, an undercoat layer 16, a hard coat layer 12, and a low refractive index layer 11, and containing the low refractive index layer 11 as an application layer having a lower refractive index than the transparent base material 13, the undercoat layer 16 is doped with a polymer containing not less than 10 wt. % of repeating units derived from monoacrylic ester or monomethacrylic ester, so that surface roughness on the low refractive index layer 11 side is 0.05-2 μm on arithmetic average.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film and an image display using the same.

[0002]

2. Description of the Related Art An antireflection film is used for a liquid crystal display (LC).
D), a plasma display panel (PDP), an electroluminescence display (ELD), and a cathode ray tube display (CRT). Glasses and camera lenses are also provided with an antireflection film. As the antireflection film, a multilayer film in which a transparent thin film of a metal oxide is laminated has conventionally been commonly used. The reason for using a plurality of transparent thin films is to prevent reflection of light of various wavelengths. The transparent thin film of a metal oxide is formed by a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method, in particular, a vacuum vapor deposition method which is a kind of the physical vapor deposition method.
Although a transparent thin film of a metal oxide has excellent optical properties as an antireflection film, the method of forming by vapor deposition has low productivity and is not suitable for mass production. The antireflection film formed by the PVD method may be formed on a support having antiglare properties due to surface irregularities depending on the application. Although the parallel light transmittance is lower than that formed on a smooth support, the reflection of the background is scattered by the surface unevenness and decreases, so it exhibits anti-glare properties, and together with the anti-reflection effect, image formation When applied to the device, the display quality is significantly improved.

[0005] Instead of a vapor deposition method, a method of forming an antireflection film by applying inorganic fine particles has been proposed. Tokunosho 6
Japanese Patent Application No. 0-59250 discloses an antireflection layer having fine pores and a particulate inorganic substance. The antireflection layer is formed by coating. The micropores are formed by performing an activation gas treatment after the application of the layer, and the gas is released from the layer. JP-A-59-50401 discloses an antireflection film in which a support, a high refractive index layer and a low refractive index layer are laminated in this order. This publication also discloses an antireflection film in which a medium refractive index layer is provided between a support and a high refractive index layer. The low refractive index layer is formed by applying a polymer or inorganic fine particles.

Japanese Patent Application Laid-Open No. 2-245702 discloses an antireflection film in which two or more kinds of ultrafine particles (for example, MgF 2 and SiO ₂ ) are mixed and the mixing ratio is changed in the film thickness direction. . The refractive index is changed by changing the mixing ratio to obtain the same optical properties as the antireflection film provided with the high refractive index layer and the low refractive index layer described in JP-A-59-50401. ing. The ultrafine particles are adhered by SiO2 generated by thermal decomposition of ethyl silicate. In the thermal decomposition of ethyl silicate, carbon dioxide and water vapor are also generated by burning the ethyl portion. JP-A-2-
As shown in FIG. 1 of Japanese Patent No. 245702, a gap is formed between the ultrafine particles due to the separation of carbon dioxide and water vapor from the layer. JP-A-5-13021 discloses that the gap between ultrafine particles existing in the antireflection film described in JP-A-2-245702 is filled with a binder. JP-A-7-48527 discloses an antireflection film containing a binder and an inorganic fine powder made of porous silica.

[0005] As means for imparting antiglare properties to the antireflection film formed by the above-mentioned coating, there are a method of applying an antireflection layer on a support having surface irregularities, and a method of reflecting mat particles for forming surface irregularities. A method of adding the compound to a coating solution for forming the prevention layer has been studied. However, in the former method,
The coating liquid of the anti-reflection layer flows from the convex portion to the concave portion, causing in-plane film thickness unevenness, and the problem that the anti-reflection performance is significantly deteriorated as compared with the coating film on the smooth surface. is there. Further, in the latter method, mat particles having a particle size of about 1 micron or more necessary to exhibit sufficient antiglare properties are embedded in a thin film having a thickness of about 0.1 to 0.3 microns. As a result, the problem of mat particles falling off occurs. For the above reasons, there has been no coating type antireflection film satisfying simultaneously the antiglare property, the antireflection property and the film strength.

[0006]

SUMMARY OF THE INVENTION The present inventor has conducted research on a low refractive index layer formed by applying inorganic fine particles. According to the study of the present inventor, it has been found that when microvoids are formed between the fine particles by stacking at least two or more inorganic fine particles, the refractive index of the layer is reduced. By forming microvoids between the fine particles, a low refractive index layer having a very low refractive index can be obtained. JP-A-2-245
In the anti-reflection film described in Japanese Patent Application Laid-Open No. 702, a gap is formed between the stacked ultrafine particles. However, the publication only suggests a gap in FIG. 1, but does not describe the optical function of the gap at all. Further, there is a problem that the low refractive index layer having voids has low strength. The low refractive index layer is disposed on the display surface of the image display device or on the outer surface of the lens. Therefore, the low refractive index layer is required to have a certain strength. The antireflection film described in JP-A-2-245702 is substantially composed of only an inorganic compound,
It is a hard but very brittle film. JP-A-5-1302
As described in Japanese Patent Publication No. 1 (1993), if the voids between the fine particles are filled with a binder, the problem of strength can be solved. However, according to the research of the present inventor, when the voids between the fine particles are filled with the binder, the optical function of the voids that lowers the refractive index of the layer is lost. Subsequently, a method of imparting anti-glare properties for further effectively reducing the reflection of the background was examined.
As a result of intensive studies including the conventional method as described above, in order to simultaneously satisfy anti-glare properties, low reflectance and film strength with a coating type, it is most appropriate to provide an anti-glare property after forming an anti-reflection film. I found it. Among the most preferred methods,
After forming an antireflection film by coating, a method of producing an antireflection film having an antiglare property by performing a step of forming surface irregularities on at least one surface of the transparent support by external pressure in this order. I came to find. The purpose of the present invention is to have a low refractive index layer as a coating layer,
An object of the present invention is to provide an anti-reflection film having an anti-reflection function and an anti-glare function comparable to an anti-reflection film made of a vapor-deposited layer. Another object of the present invention is to provide a manufacturing method capable of forming surface irregularities similar to those of a vapor-deposited layer on a coating layer surface of an antireflection film without deteriorating the antireflection function.

[0007]

The object of the present invention has been attained by the following (1) to (6) antireflection films and the following (7) antireflection film manufacturing methods. (1) A transparent support, an undercoat layer, a hard coat layer and a low refractive index layer are laminated in this order, and the low refractive index layer is a coating layer, and the refractive index of the lower refractive index layer is lower than that of the transparent support. Low refractive index anti-reflection film, the surface on the low refractive index layer side,
The undercoat layer contains a polymer having an arithmetic average roughness of 0.05 to 2 μm, and having at least 10% by weight of a repeating unit derived from a monoacrylate or monomethacrylate of alcohol or phenol. Anti-reflective coating. (2) The antireflection film according to (1), wherein the glass transition temperature of the polymer contained in the undercoat layer is 60 to 130 ° C. (3) The antireflection film according to (1), wherein the thickness of the undercoat layer, the hard coat layer, and the low refractive index layer is substantially uniform. (4) The antireflection film according to (1), wherein the low refractive index layer contains fine particles having an average particle diameter of 10 to 100 nm, and has a gap between or within the fine particles. (5) The high refractive index layer according to (1), wherein a high refractive index layer is further laminated between the hard coat layer and the low refractive index layer, and the refractive index of the high refractive index layer is higher than that of the transparent support. Anti-reflection film. (6) A middle refractive index layer is further laminated between the hard coat layer and the high refractive index layer, and the refractive index of the middle refractive index layer is higher than that of the transparent support, and The antireflection film according to (5), wherein the middle refractive index layer has a lower refractive index than the refractive index. (7) An undercoat layer, a hard coat layer, and a low refractive index layer containing a polymer having a repeating unit derived from an alcohol or phenol monoacrylate or monomethacrylate of 10% by weight or more on a transparent support. Step of forming sequentially or simultaneously by coating,
Then, a process for embossing the surface on the side of the low refractive index layer to form irregularities on the surface on the side of the low refractive index layer.

[0008]

The present inventor has studied means for bringing the surface of the coating layer into the above-mentioned surface roughness state without using fine particles as a mat material, and using a simple means such as embossing, the thickness of the coating layer is reduced. The surface roughness described above was successfully achieved while maintaining the uniformity. Therefore, the antireflection film of the present invention,
Although the low refractive index layer is a coating layer, it has an antireflection function and an antiglare function comparable to an antireflection film made of a vapor-deposited layer. The antireflection film of the present invention can be manufactured by simple steps of coating and embossing. Therefore,
It is suitable for mass production, unlike an antireflection film made of a vapor-deposited layer. By using the antireflection film as described above, reflection of external light on the image display surface of the image display device can be effectively prevented, and at the same time, background reflection can be effectively reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic structure of an antireflection film having antiglare properties according to the present invention will be described with reference to the drawings. FIG. 1 shows an example of a method of imparting an antiglare property to a coating type antireflection film. In the figure, anti-reflection film (1)
By pressing the surface on the antireflection layer (3) side with an embossing roll (4) and a backup roll (5) to form irregularities on at least one surface, anti-glare properties are exhibited without impairing anti-reflective properties I do. The substantial uniformity of the film required to maintain the anti-reflection property depends on the number and design of the light interference layers. For example, in the case of a three-layer design in which a low-refractive-index layer, a high-refractive-index layer, and a medium-refractive-index layer are stacked in this order from the air interface side with a thickness of λ / 4n, the uniformity of the film thickness of each layer Is an upper limit of ± 3%, and if it is more than 3%, the antireflection performance is remarkably deteriorated. The degree of anti-glare property is determined by film surface temperature, press pressure,
Although it can be controlled by the process conditions such as the processing speed and the mechanical properties of the transparent support having the antireflection film, the operation under milder conditions can be controlled from the viewpoint of film flatness, process stability, cost, etc. preferable.

[Surface Roughness] The surface roughness of the antireflection film can be evaluated by analyzing data obtained by observing the uneven surface of the sample provided with antiglare properties with a scanning microscope. The evaluation method of arithmetic average roughness (Ra) is based on JIS-B-
0601. In the present invention, the arithmetic average roughness (Ra) of the surface of the antireflection film is in the range of 0.05 to 2 μm.
Ra is preferably in the range of 0.07 to 1.5 μm, more preferably in the range of 0.09 to 1.2 μm, and most preferably in the range of 0.1 to 1 μm. If Ra is less than 0.05 μm, a sufficient anti-glare function cannot be obtained. When Ra exceeds 2 μm, the resolution is reduced, and the image shines white when exposed to external light.

[Formation of Antireflection Film] FIG. 2 is an example of a schematic sectional view of a low refractive index layer of the antiglare antireflection film used in the present invention. The upper side of the anti-reflection film in FIG. 2 is the surface, and the lower side is the image display device. In the example shown in FIG. 2, the low refractive index layer (11) is a porous layer. In the low refractive index layer (11), the inorganic fine particles (2) having an average particle size of 0.5 to 200 nm are used.
1) are stacked at least two or more (three in FIG. 1). And microvoids (22) are formed between the inorganic fine particles (21). Low refractive index layer (11)
Further comprises the polymer (23) in an amount of 5 to 50% by weight. The polymer (23) adheres the inorganic fine particles (21) but does not fill the microvoids (22).
The low refractive index layer (11) may be a layer made of a fluoropolymer in addition to the porous layer as in the example. As the fluorine-containing polymer, those having a high fluorine content or those having a large free volume are preferable from the viewpoint of a low refractive index, and those having crosslinkability from the viewpoint of adhesion are preferable. Regarding the type of crosslinking, a thermosetting type and an ionizing radiation curing type are commercially available.

FIG. 3 is a schematic sectional view showing various layer configurations of the antireflection film. In the embodiment shown in FIG. 3A, the transparent support (13), the undercoat phase (16), the hard coat layer (1)
2) and a low refractive index layer (11). The mode shown in FIG. 3B is a transparent support (13),
It has a layer structure of an undercoat layer (16), a hard coat layer (12), a high refractive index layer (14), and a low refractive index layer (11) in this order. As shown in (b), an antireflection film having a high refractive index layer (14) and a low refractive index layer (11) is disclosed in
As described in JP-A-50501, it is preferable that the high refractive index layer satisfies the following formula (I) and the low refractive index layer satisfies the following formula (II).

[0013]

(Equation 1)

Wherein m is a positive integer (generally 1, 2 or 3), n1 is the refractive index of the high refractive index layer, and d1 is the layer thickness (nm) of the high refractive index layer. .

[0015]

(Equation 2)

Wherein n is a positive odd number (generally 1);
n2 is the refractive index of the low refractive index layer, and d2 is the layer thickness (nm) of the low refractive index layer. The embodiment shown in FIG. 3 (c) includes a transparent support (13), an undercoat layer (16), a hard coat layer (12), a medium refractive index layer (15), and a high refractive index layer (1).
4) and a low refractive index layer (11). As shown in (c), an antireflection film having a middle refractive index layer (15), a high refractive index layer (14) and a low refractive index layer (11) is described in JP-A-59-50401. It is preferable that the middle refractive index layer satisfies the following formula (III), the high refractive index layer satisfies the following formula (IV), and the low refractive index layer satisfies the following formula (V).

[0017]

(Equation 3)

In the formula, h is a positive integer (generally 1, 2 or 3), n3 is the refractive index of the medium refractive index layer, and d3 is the thickness (nm) of the medium refractive index layer. .

[0019]

(Equation 4)

Where j is a positive integer (generally 1, 2 or 3), n4 is the refractive index of the high refractive index layer, and d4 is the layer thickness (nm) of the high refractive index layer. .

[0021]

(Equation 5)

Where k is a positive odd number (generally 1);
n5 is the refractive index of the low refractive index layer, and d5 is the layer thickness (nm) of the low refractive index layer.

It is preferable to use a plastic film as the transparent support. Examples of plastic film materials include cellulose esters (eg, triacetyl cellulose, diacetyl cellulose, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, nitrocellulose), polyamides, polycarbonates, polyesters (eg, polyethylene terephthalate, polyethylene naphthalate) , Poly-1,4-cyclohexane dimethylene terephthalate, polyethylene
1,2-diphenoxyethane-4,4′-dicarboxylate, polybutylene terephthalate), polystyrene (eg, syndiotactic polystyrene), polyolefin (eg, polypropylene, polyethylene, polymethylpentene), polysulfone, polyethersulfone , Polyarylates, polyetherimides, polymethyl methacrylates and polyether ketones. Triacetyl cellulose, polycarbonate and polyethylene terephthalate are preferred. The light transmittance of the transparent support is
It is preferably at least 80%, more preferably at least 86%. The haze of the transparent support is 2.0%
Or less, and more preferably 1.0% or less. The refractive index of the transparent support is preferably from 1.4 to 1.7.

As shown in FIG. 3B, a high refractive index layer may be provided between the low refractive index layer and the transparent support. Also,
As shown in FIG. 3C, a middle refractive index layer may be provided between the high refractive index layer and the transparent support. The high refractive index layer preferably has a refractive index of 1.65 to 2.40.
More preferably, it is 70 to 2.20. The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is 1.55 to 1 .80.

The middle refractive index layer and the high refractive index layer are preferably formed using a polymer having a relatively high refractive index.
Examples of high refractive index polymers include polystyrene, styrene copolymers, polycarbonates, melamine resins, phenolic resins, epoxy resins, and polyurethanes obtained by reacting cyclic (alicyclic or aromatic) isocyanates with polyols. . Other polymers having a cyclic (aromatic, heterocyclic, alicyclic) group and polymers having a halogen atom other than fluorine as a substituent also have a high refractive index. A polymer may be formed by a polymerization reaction of a monomer capable of radical curing by introducing a double bond. It is more preferable that the inorganic fine particles having a high refractive index are dispersed in the monomer and the initiator to be added to the above-mentioned low refractive index layer or in the polymer. As the inorganic fine particles, a metal (eg, aluminum, titanium, zirconium, antimony) oxide is preferable. When a monomer and an initiator are used, a medium-refractive-index layer or a high-refractive-index layer having excellent scratch resistance and adhesion can be formed by curing the monomer by polymerization reaction using ionizing radiation or heat after coating.

An organically substituted silicon compound may be added to the high or middle refractive index layer. As the silicon compound, a silane coupling agent or a hydrolyzate thereof used for the surface treatment of the inorganic fine particles in the low refractive index layer is preferably used. As the inorganic fine particles, a metal (eg, aluminum, titanium, zirconium, antimony) oxide is preferable. A powder or colloidal dispersion of inorganic fine particles is mixed with the above-mentioned polymer or organosilicon compound and used. The average particle size of the inorganic fine particles is 10 to 10
It is preferably 0 nm. A high refractive index layer or a medium refractive index layer may be formed from an organometallic compound having a film forming ability. It is preferable that the organometallic compound can be dispersed in an appropriate medium or is in a liquid state. The haze of the high refractive index layer and the medium refractive index layer is preferably 3% or less.

The undercoat layer contains a polymer having 10% by weight or more of a repeating unit derived from a monoacrylate or monomethacrylate of alcohol or phenol. Monoacrylates or monomethacrylates are esters of an alcohol or phenol with one acrylic or methacrylic acid. That is, the ester (monomer) has one ethylenically unsaturated group. Preferred repeating units derived from a monoacrylate or monomethacrylate of alcohol or phenol are represented by the following formula (I).

[0028]

Embedded image

In the formula (I), R ¹ is a hydrogen atom or methyl, and R ² is an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group. R ² is
It is preferably an alkyl group or a substituted alkyl group, and most preferably an (unsubstituted) alkyl group. . The number of carbon atoms of the alkyl group is preferably 1 to 12, more preferably 1 to 8, and 1 to 8.
More preferably, it is from 6 to 6, and most preferably from 1 to 4. The alkyl group may have a branch. The alkyl part of the substituted alkyl group is the same as the above-mentioned alkyl group. Examples of the substituent of the substituted alkyl group include nitro, hydroxyl, cyano, sulfo, alkoxy, aryloxy, acyloxy, sulfonamide, and epoxyalkyl groups. The aryl group preferably has 6 to 20 carbon atoms. The aryl group is preferably phenyl or naphthyl,
More preferably, it is phenyl. The aryl part of the substituted aryl group is the same as the above-mentioned aryl group. Examples of substituents on substituted aryl groups include nitro, hydroxyl,
Includes cyano, sulfo, alkyl, alkoxy, aryloxy, acyloxy, sulfonamide and epoxyalkyl groups.

The polymer has at least 10% by weight of a repeating unit derived from a monoacrylate or a monomethacrylate of an alcohol or a phenol. The proportion of the repeating unit derived from a monoacrylate or monomethacrylate of alcohol or phenol is preferably at least 20% by weight, more preferably at least 40% by weight, and more preferably 60% by weight.
It is more preferably at least 80% by weight, most preferably at least 80% by weight. It consists only of a repeating unit derived from a monoacrylate or monomethacrylate of alcohol or phenol (1
(00% by weight) of a homopolymer. The other repeating unit contained in the polymer is preferably derived from a monomer having one ethylenically unsaturated group. Examples of monomers having one ethylenically unsaturated group include acrylic acid and methacrylic acid. The molecular weight (or degree of polymerization) of the polymer is determined in consideration of the glass transition temperature of the polymer. The glass transition temperature of the polymer contained in the undercoat layer is preferably from 60 to 130 ° C, more preferably from 80 to 110 ° C.

The above polymer and another polymer may be used in combination. Examples of other polymers include gelatin, polyvinyl alcohol, polyalginic acid and its salts, cellulose esters (eg, triacetyl cellulose, diacetyl cellulose, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, nitrocellulose, hydroxyethyl cellulose, hydroxypropyl Cellulose), polystyrene and polyetherketone. Even when used in combination with another polymer, the undercoat layer preferably contains 50% by weight or more of an acrylate or methacrylate ester-based polymer, more preferably 60% by weight or more. , 70% by weight or more, and most preferably 80% by weight or more. In addition, a conventional undercoat layer for the purpose of improving adhesiveness, such as a gelatin undercoat layer, may be provided between the transparent support and the undercoat layer of the present invention.

FIG. 3 is a schematic sectional view showing the state of the antireflection film after embossing. The embodiment shown in FIG. 3A has a layer structure in the order of a transparent support (13), an undercoat layer (16), a hard coat layer (12), and a low refractive index layer (11). In the embodiment shown in FIG. 3B, the transparent support (13), the undercoat layer (16), the hard coat layer (1)
2), high refractive index layer (14), and low refractive index layer (11)
In the following order. The mode shown in FIG.
Transparent support (13), undercoat layer (16), hard coat layer (12), medium refractive index layer (15), high refractive index layer (1
4) and a low refractive index layer (11). As shown in FIG. 3, the deformation due to the embossing is concentrated on the undercoat layer, and the thickness of the hard coat layer and the antireflection layer is almost parallel. The support is slightly deformed.

The antireflection film may further be provided with a hard coat layer, a moisture proof layer, an antistatic layer and a protective layer. The hard coat layer is provided for imparting scratch resistance to the transparent support. The hard coat layer also has a function of enhancing the adhesion between the transparent support and the layer thereon. The hard coat layer can be formed using an acrylic polymer, a urethane polymer, an epoxy polymer, or a silica compound.
A pigment may be added to the hard coat layer. As a material used for the hard coat, a polymer having a saturated hydrocarbon or polyether as a main chain is preferable, a polymer having a saturated hydrocarbon as a main chain is more preferable, and a cross-linked structure is preferable. The polymer having a saturated hydrocarbon as a main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. In order to obtain a crosslinked polymer, it is preferable to use a monomer having two or more ethylenically unsaturated groups.

Examples of the monomer having two or more ethylenically unsaturated groups include esters of polyhydric alcohol and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate, 1,4-dichlorohexane diacrylate) Pentaerythritol tetra (meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethanetri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta ( (Meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinylbenzene and the like. Derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (eg, divinylsulfone), acrylamide (eg, methylenebisacrylamide) and methacryl Amides are included.

Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, a crosslinked structure may be introduced by a reaction of a crosslinkable group. Examples of crosslinkable functional groups include isocyanate groups, epoxy groups, aziridine groups, oxazoline groups, aldehyde groups, carbonyl groups, hydrazine anoacrylate derivatives, melamine, etherified methylol, esters, and urethanes to introduce a crosslinked structure. Can be used as a monomer. A functional group that exhibits crosslinkability as a result of a decomposition reaction, such as a block isocyanate group, may be used. 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 hard coat layer is preferably formed by dissolving a monomer and a polymerization initiator in a solvent and performing a polymerization reaction (and, if necessary, a crosslinking reaction) after coating. As the polymerization initiator, it is preferable to add a hydrogen abstraction type such as a benzophenone type or a radical opening type such as an acetophenone type or a triazine type alone or in combination with a monomer to a coating solution. A small amount of polymer (eg, polymethyl methacrylate, polymethyl acrylate, diacetyl cellulose, triacetyl cellulose, nitrocellulose, polyester, alkyd resin) may be added to the coating solution for the hard coat layer.

A protective layer may be provided on the low refractive index layer. The protective layer functions as a slip layer or an antifouling layer. Examples of the sliding agent used for the sliding layer include polyorganosiloxanes (eg, polydimethylsiloxane, polydiethylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, alkyl-modified polydimethylsiloxane), natural waxes (eg, carnauba wax, Candelilla wax, jojoba oil, rice wax, wood wax,
Beeswax, lanolin, whale wax, montan wax), petroleum wax (eg, paraffin wax, microcrystalline wax), synthetic wax (eg, polyethylene wax, Fischer-Tropsch wax), higher fatty acid amide (eg, stearamide, oleinamide) ,
N, N'-methylenebisstearamide), higher fatty acid esters (eg, methyl stearate, butyl stearate, glycerin monostearate, sorbitan monooleate), metal salts of higher fatty acids (eg, zinc stearate)
And fluorine-containing polymers (eg, perfluoro main chain type perfluoropolyether, perfluoro side chain type perfluoropolyether, alcohol-modified perfluoropolyether, isocyanate-modified perfluoropolyether). A fluorinated hydrophobic compound (eg, fluorinated polymer, fluorinated surfactant, fluorinated oil) is added to the stain prevention layer. The thickness of the protective layer is preferably 20 nm or less so as not to affect the antireflection function.

Each layer of the antireflection film is formed by a dip coating method,
It can be formed by coating by an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method or an extrusion coating method (US Pat. No. 2,681,294). Two or more layers may be applied simultaneously. The method of simultaneous coating is described in U.S. Pat. Nos. 2,761,791 and 2,918,898.
Nos. 3,508,947 and 3,526,528, and in Yuji Harazaki, Coating Engineering, page 253, Asakura Shoten (1973).

The anti-reflection film includes a liquid crystal display (LCD),
The present invention is applied to an image display device such as a plasma display panel (PDP), an electroluminescence display (ELD), and a cathode ray tube display (CRT). When the antireflection film has a transparent support, the transparent support side is adhered to the image display surface of the image display device.

[0039]

Example 1 (Preparation of Undercoat Layer Coating Solution) In a 500 ml glass three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, 235 ml of distilled water, dioctyl sulfosuccinate sodium salt (surfactant) 0.57 g of a 70% by weight aqueous solution of
And 1.1 g of potassium hydroxide, and stirred. 0.128 g of potassium persulfate (polymerization initiator) was added to 8 m of distilled water
The solution dissolved in 1 was further added, and immediately, a mixture of 24 g of methyl methacrylate, 4.5 g of ethyl acrylate and 1.5 g of acrylic acid was added dropwise over 3 hours. After completion of the dropwise addition, an aqueous solution of potassium persulfate was added again,
Continue heating and stirring at 80 ° C. for 3 hours to complete the polymerization reaction,
A polymer dispersion having a solid content of 25% by weight was obtained. The glass transition temperature of the obtained polymer was 91.1 ° C. 60 g of methanol was added to the polymer dispersion and stirred at room temperature for 1 hour. This was filtered through a polypropylene filter having a pore size of 10 μm to prepare an undercoat layer coating solution.

(Formation of Undercoat Layer) A gelatin undercoat layer was provided on a triacetyl cellulose film (TAC-TD80U, Fuji Photo Film Co., Ltd.) having a thickness of 80 μm, and the undercoat layer was formed on the gelatin undercoat layer. The coating solution was applied using a bar coater and dried at 120 ° C. to form an undercoat layer having a thickness of 2 μm.

(Preparation of Hard Coat Layer Coating Solution) 250 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was dissolved in 439 g of industrially modified ethanol. To the obtained solution, 7.5 g of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) and a photosensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.)
A solution of 5.0 g dissolved in 49 g of methyl ethyl ketone was added. After stirring the mixture, the mixture was filtered through a 1 μm mesh filter to prepare a coating solution for a hard coat layer.

(Formation of Hard Coat Layer) On the undercoat layer, the above-mentioned hard coat layer coating solution was applied using a bar coater and dried at 120 ° C. Next, the coating layer was cured by irradiating ultraviolet rays to form a hard coat layer having a thickness of 6 μm.

(Preparation of coating solution for low refractive index layer) A silane coupling agent (KBM-) was added to 200 g of a methanol dispersion of silica fine particles (methanol silica sol, manufactured by Nissan Chemical Industries, Ltd.).
503, manufactured by Shin-Etsu Silicone Co., Ltd.) 10 g and 0.1
After adding 2 g of N hydrochloric acid and stirring at room temperature for 5 hours, the mixture was left at room temperature for 4 days to prepare a dispersion of silane-coupled silica fine particles. To 149 g of the dispersion, 789 g of isopropyl alcohol and 450 g of methanol were added. 3.21 g of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) and a photosensitizer (Kayacure DET)
X, manufactured by Nippon Kayaku Co., Ltd.) in a solution of 1.605 g in 31.62 g of isopropyl alcohol, and further a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DP
A solution prepared by dissolving 2.17 g of HA (produced by Nippon Kayaku Co., Ltd.) in 78.13 g of isopropyl alcohol was added. The mixture was stirred at room temperature for 20 minutes, and filtered through a 1 μm mesh filter to prepare a coating solution for a low refractive index layer.

(Formation of Low Refractive Index Layer) On the hard coat layer, a low refractive index layer coating solution is applied using a bar coater.
After drying at 120 ° C., the coating layer was cured by irradiating ultraviolet rays to form a low refractive index layer (thickness: 0.1 μm).

(Embossing) The embossing roll prepared as described above and a backup roll whose surface was covered with a polyamide material were set on a single-sided embossing calender (made by Yuri Roll Co., Ltd.). The pressing pressure is 600 kg / cm, the preheat roll temperature is 90 ° C., the emboss roll temperature is 120 ° C., and the processing speed is 2 so that the low refractive index layer formed as described above contacts the emboss roll surface.
Embossing was performed under the conditions of m / min. Thus, an antireflection film was produced. About the obtained antireflection film, the average reflectance at a wavelength of 450 to 650 nm,
When the haze value and the pencil hardness of the surface were measured, the average reflectance was 1.0%, the haze was 1.5%, and the pencil hardness was H. Further, the surface of the antireflection film was 0.12 μm and had a high texture without any roughness when viewed with Ra. Also,
When the thickness of each layer was examined, the thickness of each layer was substantially uniform (average value of layer thickness ± 1% or less).

Example 2 (Preparation of Undercoat Layer Coating Solution) The polymer dispersion prepared in Example 1 was freeze-dried to obtain a polymer powder. 30 g of the polymer powder was dissolved in 135 g of cyclohexanone and 135 g of methyl ethyl ketone, and the solution was filtered through a polypropylene filter having a pore size of 10 μm to prepare a coating solution for an undercoat layer.

(Preparation of Titanium Dioxide Dispersion) Titanium dioxide (primary particle weight average particle diameter: 50 nm, refractive index: 2.7)
0) 30 parts by weight, the following anionic monomer (1) 3 parts by weight, the following anionic monomer (2) 3 parts by weight, the following cationic monomer 1 part by weight, and methyl ethyl ketone 63 parts by weight were dispersed by a sand grinder. , A titanium dioxide dispersion was prepared.

[0048]

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[0049]

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[0050]

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

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

(Preparation of antireflection film) Triacetyl cellulose film (TAC-TD80U, 80 μm thick)
Fuji Photo Film Co., Ltd.) was provided with a gelatin undercoat layer, and the above undercoat layer coating solution was coated on the gelatin undercoat layer using a bar coater, dried at 120 ° C., and dried to a thickness of 1 μm. An undercoat layer was formed. The hard coat layer coating solution prepared in Example 1 was applied on the undercoat layer using a bar coater, and dried at 120 ° C. Next, the coating layer was cured by irradiating ultraviolet rays to form a hard coat layer having a thickness of 6 μm. On the hard coat layer, a medium refractive index layer coating solution is applied using a bar coater,
Then, the coating layer was cured by irradiating ultraviolet rays to provide a medium refractive index layer (thickness: 0.081 μm). On the middle refractive index layer, a coating liquid for a high refractive index layer is applied using a bar coater, dried at 120 ° C., and then irradiated with ultraviolet rays to cure the coating layer, thereby forming a high refractive index layer (thickness: 0.053 μm). The coating solution for the low refractive index layer used in Example 1 was applied on the high refractive index layer using a bar coater, dried at 120 ° C., and then irradiated with ultraviolet rays to cure the coating layer, thereby obtaining a low refractive index. A rate layer (thickness: 0.092 μm) was provided. An embossing treatment was performed in the same manner as in Example 1 except that a backup roll whose surface was covered with a silicone rubber material was used, to produce an antireflection film.

Regarding the obtained antireflection film, 450 to 6
When the average reflectance, haze value, surface pencil hardness and surface contact angle with water at a wavelength of 50 nm were measured, the average reflectance was 0.25%, the haze value was 1.5%, the pencil hardness was 2H, and the contact angle was 35 °. there were. Further, the surface of the antireflection film had a high texture of Ra 0.15 μm without any roughness by visual observation. Further, when the thickness of each layer was examined, the thickness of each layer was substantially uniform (average value of layer thickness ± 1% or less).

Example 3 The thickness of the low refractive index layer was 0.07
Except that the thickness was changed to 2 μm, an undercoat layer, a hard coat layer, a medium refractive index layer,
A high refractive index layer and a low refractive index layer were provided. A solution of a crosslinkable fluoropolymer is applied on the low refractive index layer,
C. to form an overcoat layer having a thickness of 0.02 μm. After the preparation of the sample, embossing was performed in the same manner as in Example 1. About 450-650 about the obtained antireflection film
When the average reflectance, haze value and pencil hardness of the surface at a wavelength of nm were measured, the average reflectance was 1.0%, the haze was 1.5%, and the pencil hardness was H. The average reflectance, haze value, pencil hardness of the surface, and surface contact angle with water of the obtained antireflection film at a wavelength of 450 to 650 nm were measured. The average reflectance was 0.35%, and the haze value was 1.5%. , Pencil hardness 2H and contact angle 106 °.
The surface of the antireflection film had a Ra of 0.10 μm and had a high texture without any roughness. Further, when the thickness of each layer was examined, the thickness of each layer was substantially uniform (average value of layer thickness ± 1% or less). A personal computer (PC982)
When attached to the surface of a liquid crystal display device of 1NS / 340W (manufactured by NEC Corporation), it was possible to obtain a display of high display quality with very little reflection of external light and reduced reflection of the background. In addition, fingerprints are hardly attached to the surface,
Even if it adhered, it could be easily wiped off with a cleaning cloth.

Comparative Example 1 A triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm was provided with a gelatin undercoat layer, and a (methacrylic acid-based polymer) was formed on the gelatin undercoat layer. Except that a hard coat layer was provided directly (without an undercoat layer containing
Embossing was performed in the same manner as in Example 1 to produce an antireflection film. About 450-650 nm about the obtained antireflection film
The average reflectance, the haze value and the pencil hardness of the surface at the wavelength of were measured. The average reflectance was 1.2%, the haze was 0.2%, and the pencil hardness was H at Ra 0.02 μm. The anti-reflection film did not have an anti-glare (anti-glare) function.

Comparative Example 2 A gelatin undercoat layer was provided on a triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm, and a (methacrylic acid-based polymer) was formed on the gelatin undercoat layer. Except that a hard coat layer was provided directly (without an undercoat layer containing
Embossing was performed in the same manner as in Example 2 to produce an antireflection film. About 450-650 nm about the obtained antireflection film
The average reflectance, haze value and pencil hardness of the surface at a wavelength of were measured, and the average reflectance was 0.55%, the haze was 0.4%, and the pencil hardness was H at Ra 0.02 μm. The anti-reflection film did not have an anti-glare (anti-glare) function.

Comparative Example 3 Crosslinked polymethyl methacrylate particles (MX-5) having a particle size of 3 μm were added to the coating liquid for the hard coat layer.
(00H, manufactured by Soken Chemical Co., Ltd.) Except for adding 5.0 g, an undercoat layer, a hard coat layer containing fine particles, and a low refractive index layer were sequentially formed on the transparent support in the same manner as in Example 1.
An anti-reflective coating was made (without embossing). As a result, a remarkable distribution occurs in the thickness of the low refractive index layer,
The average reflectance at a wavelength of 50 nm is 2.0%,
No sufficient antireflection effect was obtained. Ra is 0.18
μm. When the thickness of each layer was examined, the thickness of each layer was uneven (average value of layer thickness ± 5).
%).

Comparative Example 4 Crosslinked polymethyl methacrylate particles (MX-5) having a particle size of 3 μm were added to the coating solution for the hard coat layer.
00H, manufactured by Soken Chemical Co., Ltd.) In the same manner as in Example 2 except that 5.0 g was added, an undercoat layer, a hard coat layer containing fine particles, a medium refractive index layer, a high refractive index layer, and a low refractive index layer were sequentially formed. To form an anti-reflective coating (without embossing).
As a result, a remarkable distribution occurs in the thickness of the low refractive index layer,
The average reflectance at a wavelength of 0 to 650 nm was 2.0%, and a sufficient antireflection effect was not obtained. Ra was 0.14 μm. Further, when the thickness of each layer was examined, the thickness of each layer was non-uniform (some portions exceeded the average value of layer thickness ± 5%).

[Brief description of the drawings]

FIG. 1 is a schematic view showing a method for imparting antiglare properties to an antireflection film.

FIG. 2 is a schematic cross-sectional view of an example of a low refractive index layer of an antireflection film.

FIG. 3 is a schematic sectional view showing a state of an antireflection film after embossing.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 antireflection film 2 transparent support 3 antireflection layer 4 embossing roll 5 backup roll 11 low refractive index layer 12 hard coat layer 13 transparent support 14 high refractive index layer 15 medium refractive index layer 16 undercoat layer 21 inorganic fine particles 22 microvoid 23 polymer

Claims (7)

[Claims] 1. A transparent support, an undercoat layer, a hard coat layer and a low refractive index layer are laminated in this order, wherein the low refractive index layer is a coating layer, and the refractive index layer is lower than the refractive index of the transparent support. Wherein the surface on the low refractive index layer side has an arithmetic average roughness of 0.05 to 2 μm, and the undercoat layer is a monoacrylate or monomethacrylate of alcohol or phenol. An antireflection film comprising a polymer having a repeating unit derived from an acid ester in an amount of 10% by weight or more. 2. The antireflection film according to claim 1, wherein the polymer contained in the undercoat layer has a glass transition temperature of 60 to 130 ° C. 3. The antireflection film according to claim 1, wherein the thicknesses of the undercoat layer, the hard coat layer and the low refractive index layer are substantially uniform. 4. The low refractive index layer has an average particle size of 10 to 100.
The anti-reflection film according to claim 1, wherein the anti-reflection film contains fine particles having a particle size of nm and has a gap between the fine particles or within the fine particles. 5. A method according to claim 1, wherein the hard coat layer and the low refractive index layer have
The antireflection film according to claim 1, further comprising a high refractive index layer laminated thereon, wherein the refractive index of the high refractive index layer is higher than that of the transparent support. 6. Between the hard coat layer and the high refractive index layer,
6. A refractive index of the middle refractive index layer is higher than a refractive index of the transparent support, and a refractive index of the middle refractive index layer is lower than a refractive index of the high refractive index layer. 2. The antireflection film according to 1. 7. An undercoat layer, a hard coat layer, and a low refractive index containing a polymer having a repeating unit derived from an alcohol or phenol monoacrylate or monomethacrylate at 10% by weight or more on a transparent support. A method for producing an antireflection film, comprising the steps of sequentially or simultaneously forming layers by coating, and embossing the surface on the low refractive index layer side to form irregularities on the surface on the low refractive index layer side.