JP2003294908A - Antireflection film, method for manufacturing the same, polarizing plate and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin antireflection film with excellent visibility, a polarizing plate using the film and an image display device using the polarizing plate. <P>SOLUTION: In the antireflection film having structure layers including an antireflection layer on a supporting body comprising cellulose acylate, the supporting body has 10 to 70 μm thickness and the layer in contact with the supporting body in the structural layers is formed from a coating liquid containing a solvent which does not dissolve the supporting body. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antireflection film, a method for producing the same, a polarizing plate using the same, and an image display device.

[0002]

2. Description of the Related Art Antireflection films are used in liquid crystal display devices (L
It is provided in various image display devices such as a CD), a plasma display panel (PDP), an electroluminescence display (ELD) and a cathode ray tube display (CRT). Anti-reflection film is also provided on the glasses and the lens of the camera. Above all, an antireflection film made of cellulose acylate has been widely used for various applications, particularly as a protective film for a polarizing plate for a liquid crystal display device.
Japanese Patent Application Laid-Open No. 11-6902 discloses a film having a three-layer antireflection film formed by wet coating, which uses a layer in which at least two inorganic fine particles are stacked in a low refractive index layer to contain microvoids. There is. A technique for providing an antireflection film that achieves both film strength and low reflectance at an inexpensive manufacturing cost by all-wet coating has been disclosed. However, the conventional support made of cellulose acylate has a large thickness of 80 μm, and it has been required to further thin the antireflection film in order to reduce the thickness of the liquid crystal display device. However, when the thickness of the support made of cellulose acylate is reduced, it becomes difficult to maintain the smoothness of the film surface when a coating layer having a necessary function is provided thereon, and there is a problem that visibility is deteriorated. It was In particular, in an antireflection film using thin film interference, deterioration of the smoothness of the film surface leads to unevenness of the film thickness, so that the antireflection performance and the visibility are significantly deteriorated.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin antireflection film having excellent visibility, a polarizing plate using the same, and an image display device using the polarizing plate.

[0004]

According to the present invention, an antireflection film, a polarizing plate, and a liquid crystal display device having the following constitutions are provided to achieve the above object of the present invention. 1. On a support made of cellulose acylate, in an antireflection film having a constituent layer containing an antireflection layer,
An antireflection film, wherein the support has a thickness of 10 to 70 μm, and among the constituent layers, a layer in contact with the support is formed from a coating solution containing a solvent that does not dissolve the support. 2. In a method for producing an antireflection film, which comprises coating a constituent layer including an antireflection layer on a support made of cellulose acylate, a coating solution containing a solvent in which the support has a thickness of 10 to 70 μm and does not dissolve the support. On the support,
A method for producing an antireflection film, which comprises the step of being formed by drying. 3. 2. The antireflection film as described in 1 above, wherein the layer in contact with the support is a hard coat layer. 4. 4. The antireflection film as described in 1 or 3 above, which does not include an antiglare layer containing matte particles. From specular reflectance of 450 nm at 5.5 degree incidence to 65 nm
CI in the wavelength range from 380 nm to 780 nm with an average value of 0.5% or less in the wavelength range up to 0 nm
E The tint of the specular reflection light with respect to the 5 degree incident light of the standard light source D65 is such that the a * and b * values of the CIE1976L * a * b * color space are −7 ≦ a * ≦ 7 and −10 ≦ b *, respectively. ≤10
Within the range of 1, 3, or 4 above
The antireflection film as described in any of 1. 6. Each layer of the antireflection film is formed by coating a coating composition containing a film-forming solute and at least one solvent, drying the solvent, and curing with heat and / or ionizing radiation. The antireflection film as described in any one of the items 1 and 3 to 5, which is characterized. 7. The cellulose acylate containing 1% by volume or more and 99% by volume or less of a metal oxide having an average particle size of 1 nm or more and 400 nm or less in the support, the above-mentioned 1, 3 to 6
The antireflection film as described in any of 1. 8. Cellulose acylate is cellulose triacetate, The antireflection film in any one of said 1, 3-7 characterized by the above-mentioned. 9. A polarizing plate using the antireflection film as described in any one of 1 and 3 to 8 as a protective film on at least one surface. Ten. An image display device comprising at least one polarizing plate as described in 9 above. 11. T having at least one polarizing plate described in 9 above
A transmissive, reflective, or transflective liquid crystal display device in N, STN, VA, IPS, OCB, and ECB modes.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The basic constitution of the antireflection film made of the cellulose acylate of the invention will be described with reference to the drawings.

[Structure of Antireflection Film] FIG. 1 is a schematic sectional view showing a basic layer structure of the antireflection film used in the present invention. The embodiment shown in FIG. 1 shows an antireflection film comprising a support 1 made of cellulose acylate, a hard coat layer 2, a medium refractive index layer 3, a high refractive index layer 4 and a low refractive index layer 5. In such an antireflection film having a three-layer structure, the optical film thickness of each of the medium refractive index layer, the high refractive index layer, and the low refractive index layer, that is, the product of the refractive index and the film thickness, with respect to the design wavelength λ It is described in JP-A-59-50401 that nλ / 4 is preferable or a multiple thereof. However, in order to realize the low reflectance and the reflectance characteristic in which the tint of the reflected light is reduced according to the present invention, the medium refractive index layer has the following formula (I) for the design wavelength λ (= 500 nm). It is preferable that the high refractive index layer satisfies the following formula (II) and the low refractive index layer satisfies the following formula (III).

[0007]   lλ / 4 × 0.80 <n1d1 <lλ / 4 × 1.00 (I)

[0008]   mλ / 4 × 0.75 <n2d2 <mλ / 4 × 0.95 (II)

[0009]   nλ / 4 × 0.95 <n3d3 <nλ / 4 × 1.05 (III)

Where l is 1, n1 is the refractive index of the medium refractive index layer, and d1 is the thickness of the medium refractive index layer (n
m), m is 2, n2 is the refractive index of the high refractive index layer, and d2 is the layer thickness (nm) of the high refractive index layer, n is 1 and n3 is low refractive index. Is the refractive index of the index layer,
And d3 is the layer thickness (nm) of the low refractive index layer. Furthermore, for example, triacetyl cellulose (refractive index: 1.4
For a transparent support consisting of 9) having a refractive index of 1.45 to 1.55, n1 is 1.60 to 1.65 and n2 is 1.8.
5 to 1.95 and n3 must have a refractive index of 1.35 to 1.45, for example, a refractive index of 1.55 to 1.65 made of polyethylene terephthalate (refractive index: 1.66).
N1 is 1.65 to 1.7.
5, n2 is 1.85 to 2.05, and n3 is 1.35 to 1.5.
It should have a refractive index of 45. When the material for the medium-refractive index layer or high-refractive index layer having the above-mentioned refractive index cannot be selected, it is equivalent to combining a layer having a higher refractive index and a layer having a lower refractive index than the set refractive index. It is well known that the principle of a film can be used to form a layer that is substantially optically equivalent to a medium-refractive index layer or a high-refractive index layer having a set refractive index, and also for realizing the reflectance characteristics of the present invention. Can be used. The “substantially three layers” of the present invention also includes four or five antireflection layers using such an equivalent film.

The reflectance characteristics of the present patent, which are achieved by the above-mentioned layer structure, can achieve both low reflection and reduction of the tint of reflected light, and therefore, for example, on the outermost surface of a liquid crystal display device. When applied, a display device having unprecedented high visibility can be obtained. Since the average value of the specular reflectance at wavelengths of 5 degrees from 450 nm to 650 nm is 0.5% or less, the reduction in visibility due to the reflection of external light on the display device surface is prevented to a sufficient level. it can. Further, the tint of specular reflection light with respect to the 5 degree incident light of the CIE standard light source D65 in the wavelength range of 380 nm to 780 nm is a in the CIE1976L * a * b * color space.
* And b * values are −7 ≦ a * ≦ 7 and −10 ≦, respectively.
By setting it within the range of b * ≦ 10, the tint of the reddish purple to blue-violet reflected light, which has been a problem in the conventional multilayer antireflection film, is reduced, and 0 ≦ a * ≦ 5 and − 7 ≦
By setting it within the range of b * ≦ 0, it is significantly reduced, and when applied to a liquid crystal display device, the tint when a high-luminance external light such as an indoor fluorescent lamp is slightly reflected is neutral. ,I do not mind.

[Support] Among the cellulose acylates used for the support of the present invention, triacetyl cellulose is preferred, and the one disclosed in JP-A No. 2001-1745 is particularly preferred.

For the purpose of increasing the surface hardness of the support,
The metal oxide fine particles can be added to the dope of cellulose acylate. As the metal oxide fine particles used in the present invention, metal oxide particles having a Mohs hardness of 7 or more are preferable. Specific examples include silicon dioxide, titanium diacid, zirconium oxide, and aluminum oxide.
Silicon dioxide and aluminum oxide, which have a small difference in refractive index from cellulose acylate, are more preferable.

The average particle diameter of these metal oxide fine particles is 1 nm or more and 400 nm or less, more preferably 5 nm.
Or more and 200 nm or less, more preferably 10 nm or more 1
00 nm or less is preferable. If it is less than 1 nm, it is difficult to disperse, and agglomerated particles are likely to be formed.

The amount of these fine particles added is 1 to 99% by volume of cellulose acylate, preferably 5 to 80% by volume, more preferably 5 to 50% by volume, and 5 to 20% by volume. % Is particularly preferable.

Generally, metal oxide fine particles have a large surface hydrophilicity and a poor affinity with cellulose acylate, so that the interface is easily broken and the film is cracked and scratch resistance is not improved simply by mixing the two. Have difficulty. In order to improve the affinity between the inorganic fine particles and cellulose acylate,
The surface of the inorganic fine particles is preferably surface-treated with a surface modifier containing an organic segment.

The surface modifier is required to form a bond with the inorganic fine particles on the one hand and have a high affinity with the cellulose acylate on the other hand, and the functional group capable of forming a bond with the metal is silane or aluminum. Preferred are metal alkoxide compounds such as titanium and zirconium, compounds having anionic groups such as phosphoric acid, sulfonic acid and carboxylic acid groups, compounds having amino groups and compounds having amide groups. The organic segment preferably has a structure having an affinity for cellulose acylate, and more preferably contains a polar group such as an ester group, an epoxy group, or an ether group. Particularly preferred is a metal alkoxide compound, or a surface modifier having an anionic group and an ester group, an epoxy group or an ether group.

Representative examples of these surface modifiers are listed below. Silane coupling agent _{H 2 C = C (CH 3} ) COOC 3 H 6 Si (OCH 3) 3 H 2 C = CHCOOC 3 H 6 Si (OCH 3) 3

[0019]

[Chemical 1]

ClCH ₂ CH ₂ —CH ₂ OC ₃ H ₆ Si (OCH ₃ ) ₃ R (OCH ₂ CH ₂ ) _n OC ₃ H ₆ Si (OCH ₃ ) ₃ R (OCH ₂ CH (CH ₃ )) _n OC ₃ H ₆ Si (OCH ₃ )
₃ ROCO (CH ₂ ) _n Si (OCH ₃ ) ₃ (n = 1 is an integer of 1 to 10, R is an alkyl group such as methyl, ethyl, propyl, butyl) CH ₃ COCH ₂ COOC ₃ H ₆ Si (OCH ₃ ) _{3 (CH 3 CH 2 O) 3} POC 3 H 6 Si (OCH 2 CH 3) 3 such as titanate coupling agent _{C 17 H 35 COOTi (OCH (} CH 3) 2) 3 specifically Ajinomoto Co. Plane Act (KRTTS,
KR46B, KR55, KR41B, KR38S, KR
138S, KR238S, 338X, KR44, KR9
SA) Aluminum coupling agent Specifically, Planeact AL-M (manufactured by Ajinomoto Co., Inc.)
Saturated carboxylic acid CH ₃ COOH, C ₂ H ₅ COOH, etc. C _n H _{2n + 1} COOH (n = 1 to 10) Unsaturated carboxylic acid Oleic acid, etc. Hydroxycarboxylic acid Citric acid, Tartaric acid, etc. Dibasic acid Oxalic acid, Malon Aromatic carboxylic acid such as acid, succinic acid, etc. Terminal carboxylic acid ester compound such as benzoic acid RCOO (C ₅ H ₁₀ COO) _n H (n = 1 to 5), H ₂ C = CHCOO (C ₅ H ₁₀ COO) _n H ( n = 1,
2,3) etc. Phosphoric acid H ₂ C = C (CH ₃ ) COOC ₂ H ₄ OCOC ₅ H ₁₀ OPO
(OH) ₂ (H ₂ C = C (CH ₃ ) COOC ₂ H ₄ OCOC ₅ H ₁₀ O) ₂
POOH, etc. Phosphonic acid Phenylphosphonic acid, etc. Sulfonic acid Benzenesulfonic acid H ₂ C = C (CH ₃ ) COOC ₂ H ₄ OSO ₃ H, etc. Polyoxyethylene derivative Polyoxyethylene aryl ether Polyoxyethylene alkyl ether Polyoxyethylene aryl ester Poly Oxyethylene alkyl ester, etc.

The surface modification of these fine particles is preferably performed in a solution. Fine particles are added to the solution in which the surface modifier is dissolved, and ultrasonic waves, a stirrer, a homogenizer,
It is preferable to use a dissolver, a planetary mixer, a paint shaker, a sand grinder, a kneader, etc. while stirring and dispersing.

The solution for dissolving the surface modifier is preferably an organic solvent having a large polarity. Specific examples thereof include known solvents such as alcohols, ketones, and esters, but a solvent having the same composition as the solvent for the cellulose acylate dope is preferable.

The metal oxide fine particles can be mixed with the cellulose acylate by adding the metal oxide fine particles to the dope of the cellulose acylate and mixing / dispersing the metal oxide. The metal oxide finely dispersed by surface treatment in advance. A method of adding fine particles to the dope of cellulose acylate is preferable. It is preferable to further disperse after addition, a dissolver, a planetary mixer, a sand grinder, a kneader,
It is preferable to uniformly mix and disperse with a roll mill or the like.

The thickness of the finished (after dried) cellulose acylate film is in the range of 10 to 70 μm in the antireflection film of the present invention. Preferably 20-60μ
The range is m, and the range of 30 to 50 μm is more preferable.

The light transmittance of the support is preferably 80% or more, more preferably 86% or more. The haze of the transparent support is preferably 2.0% or less, more preferably 1.0% or less.
The transparent support preferably has a refractive index of 1.4 to 1.7. In the present invention, the constituent layer in contact with the support is formed from a coating solution containing a solvent that does not dissolve the support. Examples of such a constituent layer include a hard coat layer, an adhesion layer, a hard coat layer also serving as a high refractive index or high refractive index layer, a medium refractive index layer, and a hard coat layer serving also as a medium refractive index layer, which will be described later.

Solvents that do not dissolve triacetyl cellulose include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol, Cyclohexanol, isobutyl acetate, methyl isobutyl ketone, 2-octanone, 2
-Pentanone, 2-hexanone, 2-heptanone, 3-
Examples include pentanone, 3-heptanone, and 4-heptanone. These can be used alone or in combination of two or more.

The solvent for the layer includes a solvent that does not dissolve the support, but a solvent that dissolves the support may be mixed and used. As a solvent for dissolving triacetyl cellulose, ethers having 3 to 12 carbon atoms: specifically, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide,
1,4-dioxane, 1,3-dioxolane, 1,3,5
-Ketones having 3 to 12 carbon atoms such as trioxane, tetrahydrofuran, anisole and phenetole: specifically, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, and methyl Cyclohexanone etc. has 3 to 1 carbon atoms
Esters of 2: specifically, two or more kinds such as ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, n-pentyl acetate, and γ-ptyrolactone. Organic solvent having a functional group: Specifically, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-methoxyethanol, 2-propoxyethanol, 2-butoxy. Examples thereof include ethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate and the like. These can be used alone or in combination of two or more.

The weight ratio (A / B) of the total amount (A) of the solvent that dissolves triacetyl cellulose and the total amount (B) of the solvent that does not dissolve triacetyl cellulose is 5/95 to 50.
/ 50 is preferable, and more preferably 10/90 to 40 /
It is 60, and more preferably 15/85 to 30/70.

[Hard Coat Layer] The hard coat layer is provided to impart 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 above it. The hard coat layer was obtained by adding an inorganic filler such as silica or alumina to a composition prepared by dissolving a polyfunctional acrylic monomer, urethane acrylate, an oligomer such as epoxy acrylate, or a polymerization initiator in a solvent, if necessary. It is preferably formed by coating the coating composition, drying the solvent, and curing with heat and / or ionizing radiation.

When the hard coat layer and the support are in contact with each other, if the solvent of the coating solution for forming the hard coat layer is a solvent that corrodes the support, the smoothness of the film surface will be impaired. It is preferred that the component is a solvent that does not dissolve the support. Furthermore, when the adhesion between the support and the hard coat layer is required, at least one solvent that dissolves the cellulose acylate support,
It is preferable to be composed of at least one solvent that does not dissolve the cellulose acylate support. More preferably, at least one of the solvents that does not dissolve the cellulose acylate support has a boiling point higher than that of at least one of the solvents that dissolves the cellulose acylate. More preferably, the boiling point temperature difference between the solvent having the highest boiling point among the solvents that does not dissolve the cellulose acylate support and the highest boiling point solvent that dissolves the cellulose acylate support is 30 ° C. or more. That is, most preferably it is 50 ° C. or higher.

[High and Medium Refractive Index Layer] The medium and high refractive index layers are coated with a coating composition containing inorganic fine particles having a high refractive index, a heat or ionizing radiation curable monomer, an initiator and a solvent. Formed by drying the solvent, curing with heat and / or ionizing radiation. As inorganic fine particles,
It is preferable to use at least one metal oxide selected from oxides of Ti, Zr, In, Zn, Sn, and Sb. The medium-refractive index layer and the high-refractive index layer thus formed are excellent in scratch resistance and adhesion as compared with those obtained by coating and drying a polymer solution having a high refractive index. In order to secure dispersion stability and film strength after curing, etc., JP-A-11-153703 and US Pat. No. 6,210,858B
It is preferable that a polyfunctional (meth) acrylate monomer and an anionic group-containing (meth) acrylate dispersant as described in 1) are included in the coating composition.

The average particle diameter of the inorganic fine particles is 1 to 100 nm in terms of the average particle diameter measured by the Coulter counter method.
Is preferred. If it is 1 nm or less, the specific surface area is too large, and the stability in the dispersion is poor, which is not preferable. When it is 100 nm or more, visible light is scattered due to the difference in refractive index with the binder, which is not preferable. The haze of the high refractive index layer and the medium refractive index layer is preferably 3% or less, and more preferably 1% or less.

[Low Refractive Index Layer] For the low refractive index layer, a fluorine-containing compound that is cured by heat or ionizing radiation is used.
The dynamic friction coefficient of the cured product is preferably 0.03 to 0.1.
5. The contact angle with pure water is preferably 100 to 120 degrees. If the coefficient of kinetic friction is higher than 0.15, scratches are likely to occur when the surface is rubbed, which is not preferable. If the contact angle to pure water is less than 100 degrees, fingerprints, oil stains and the like are likely to adhere, which is not preferable from the viewpoint of antifouling property. Examples of the curable fluorine-containing polymer compound include a perfluoroalkyl group-containing silane compound (for example, (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane), a fluorine-containing monomer and a crosslinkable group. Examples thereof include a fluorinated copolymer having a monomer for imparting a constitutional unit. Specific examples of the fluorine-containing monomer unit include, for example, fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc. ),
Partial or fully fluorinated alkyl ester derivatives of (meth) acrylic acid (for example, biscoat 6FM (Osaka Organic Chemicals) or M-2020 (Daikin)), fully or partially fluorinated vinyl ethers, and the like. However, hexafluoropropylene is particularly preferable from the viewpoint of low refractive index and easy handling of the monomer. Examples of the monomer for imparting a crosslinkable group include a (meth) acrylate monomer having a crosslinkable functional group in advance in the molecule such as glycidyl methacrylate, as well as a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, and the like (meth ) Acrylate monomers (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, etc.) can be mentioned. The latter is capable of introducing a crosslinked structure after copolymerization, which is disclosed in JP-A-10-25388 and JP-A-10-147.
No. 739, which is particularly preferable.

Further, not only a polymer having the above-mentioned fluorine-containing monomer as a constitutional unit, but also a copolymer with a monomer not containing a fluorine atom may be used. The monomer unit that can be used in combination is not particularly limited, and examples thereof include olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic acid esters (methyl acrylate,
Methyl acrylate, ethyl acrylate, acrylic acid 2-
Ethylhexyl), methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyltoluene, α-methylstyrene, etc.), vinyl ethers (methyl vinyl ether) Etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tert-butyl acrylamide, N-cyclohexyl acrylamide, etc.), methacrylamides, acrylonitrile derivatives, and the like. JP-A-10-25388 and JP-A-10-147.
It is disclosed by Japanese Patent No. 739.

Further, as a means for lowering the dynamic friction coefficient in order to impart scratch resistance, it is possible to introduce a copolymerized unit capable of improving slipperiness. A method for introducing a polydimethylsiloxane segment into the main chain is disclosed in JP-A-11-228.
It is disclosed in Japanese Patent No. 631 and is particularly preferable.

The fluorine-containing resin used for forming the low refractive index layer is preferably added with ultrafine Si oxide particles in order to impart scratch resistance. From the viewpoint of antireflection property, the lower the refractive index, the more preferable, but as the refractive index of the fluororesin is lowered, the scratch resistance deteriorates. Therefore, by optimizing the refractive index of the fluorine-containing resin and the addition amount of the Si oxide ultrafine particles, it is possible to find the best balance between scratch resistance and low refractive index. As Si oxide ultrafine particles,
The silica sol dispersed in a commercially available organic solvent may be added to the coating composition as it is, or various commercially available silica powders may be dispersed in an organic solvent and used.

[Layer Provided If Desired] The antireflection film may be further provided with a forward scattering layer, an antistatic layer or a protective layer.

The forward scattering layer is provided in order to provide the effect of improving the viewing angle when the viewing angle is tilted vertically and horizontally when applied to a liquid crystal display device. By dispersing fine particles having different refractive indexes in the hard coat layer, the hard coat layer can also serve as a hard coat function.

When a multilayer antireflection film obtained by wet-coating the coating composition of the present invention is provided with surface irregularities to obscure background reflection and impart antiglare properties, matte particles as generally used are contained. Rather than forming an antireflection layer on a layer with surface irregularities, forming the surface irregularity structure after forming the antireflection layer by an embossing method improves the film thickness uniformity and improves the antireflection performance. Therefore, it is preferable.

Each layer of the antireflection film is formed by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, a microgravure method or an extrusion coating method (US Pat. No. 2,681,294). ), It can be formed by coating. The microgravure method and the gravure method are preferable from the viewpoint of eliminating drying unevenness by minimizing the wet coating amount, and the gravure method is particularly preferable from the viewpoint of film thickness uniformity in the width direction. Two or more layers may be applied simultaneously. For the simultaneous coating method, see US Pat.
61791, 2941898, and 3508947.
Nos. 3526528 and Yuji Harasaki,
Coating Engineering, page 253, Asakura Shoten (1973). The microgravure coating method is particularly preferable.

In the microgravure coating method used in the present invention, a gravure roll having a diameter of about 20 to 50 mm and engraved with a gravure pattern on the entire circumference is provided below the support.
And, while rotating the gravure roll in the reverse direction with respect to the transport direction of the support, the doctor blade scrapes off the excess coating liquid from the surface of the gravure roll, and the fixed amount of the coating liquid is on the upper surface of the support. The coating method is characterized in that the coating liquid is transferred to the lower surface of the support at a position to perform coating.

In order to prevent streak failure on the coating surface, a bead portion of the coating liquid is provided between the roll surface of the gravure roll to which the coating liquid is excessively supplied and the flexible support which continuously runs. In the gravure coating apparatus that applies a desired amount of coating liquid to the flexible support by pressing the flexible support against the gravure roll using a backup roll while forming, in the vicinity of the upstream side of the gravure roll rotation direction of the bead portion. It is preferable that a liquid supply means is provided in and the coating liquid is supplied from the liquid supply means to the gravure roll. In this case, the liquid supply means has an inclined surface which is inclined downward in the roll surface direction of the gravure roll, and the coating liquid is made to flow down to the inclined surface to supply the liquid, and between the tip of the inclined surface and the roll surface. Is 0
It is preferable to have a gap of more than 400 μm and less than 400 μm. This is because the coating liquid is allowed to flow down to the inclined surface, so that stable liquid supply to the roll surface can be performed, and a gap of more than 0 μm and 400 μm or less is provided between the tip of the inclined surface and the roll surface. By forming it, the tip of the inclined surface does not come into contact with the roll surface, and the blocking effect of the coating liquid described above can be exerted. It is more preferable that this gap is more than 0 μm and 200 μm or less. By setting the upper limit of the gap to 200 μm or less, it is possible to reliably prevent the coating liquid from flowing down from the gap, and thus it is possible to reliably prevent the coating liquid from returning. It is important to prevent the excess coating liquid in the bead portion from being immediately dammed and flowing down to the lower portion of the gravure roll even when the liquid returns. Therefore, the roll side tip position of the inclined surface is drawn from the center of the gravure roll toward the contact point where the flexible support contacts the gravure roll, and the line drawn toward the roll surface side tip of the inclined surface. It is preferable that the center angle formed by and is 45 ° or less. Further, if the angle of the inclined surface of the liquid supply means is too large, the coating liquid flowing through the inclined surface is disturbed, so it is preferable that the downward inclination angle of the inclined surface does not exceed 15 ° with respect to the horizontal.

It is preferable to form a multi-layer coating film by one-time conveyance from the delivery of the strip-shaped support to the winding. Multi-layer coating for producing a multi-layer coating film in which multiple coating layers are formed on the strip-shaped support. In a membrane manufacturing apparatus, in a casing having an inlet and an outlet of the strip-shaped support between a feeder for the strip-shaped support and a winder for winding the strip-shaped support arranged on a floor surface of a production chamber. A feed roller that conveys the belt-shaped support along a conveyance path, an applicator that is provided in the conveyance path to form one coating layer on the belt-shaped support, and a dryer that dries the coating layer. It is preferable to arrange as many coating devices as a unit by incorporating them integrally as many as the number of multilayer coating layers formed on the belt-shaped support.

In the manufacturing apparatus, a feed roller that conveys the belt-shaped support along a conveyance path is provided in a casing having an inlet and an outlet of the belt-shaped support, and dust of the belt-shaped support is provided in the conveyance path. A dust remover for removing the dust, a dust remover configured as a unit by at least integrally incorporating it, and a feed roller for conveying the belt-shaped support along a conveyance path in a casing having an inlet and an outlet of the belt-shaped support, A heat treatment apparatus which is provided in the transport path and heat-treats the belt-shaped support, and which is configured as a unit by at least integrally incorporating it, and the belt-shaped support in a casing having an inlet and an outlet of the belt-shaped support. At least a feed roller for transporting the sheet along the transport path, and a surface inspection device provided on the transport path for inspecting the coated surface state of the belt-shaped support. A surface inspection device that is physically incorporated and configured as a unit, the dust removing device is disposed between the delivery device and the coating device, and the strip-shaped support is provided between the coating device and the winding device. It is preferable that the heat treatment apparatus and the surface inspection apparatus are arranged in this order from the upstream side in the body transport direction.

A fan filter unit is provided at the air outlet formed on the ceiling surface of the casing of each of the above devices, and an air exhaust port is formed at the bottom of the casing so that clean air blown from the fan filter unit into the casing. Is preferably exhausted from the air exhaust port.

The transport path of the belt-shaped support in each of the above-mentioned devices has a box-shaped or tubular transport path case having an inlet and an outlet of the belt-shaped support along the transport path and an air inlet and an air outlet. It is preferable that clean air is supplied to the air introduction port.

The dryer of the coating apparatus is divided into three or more drying zones along the transport direction of the belt-like support, and a supply means and a discharge means for supplying dry air are provided for each drying zone. In addition, it is preferable that a fine pressure difference meter is provided for controlling the static pressure between the drying zones.

The coating machine is any one of a direct gravure coater, a reverse coater, a kiss coater, a micro gravure coater, a bar coater and an extrusion coater, and the coating machines are preferably interchangeable with each other.

The coating machine in the coating apparatus is preferably arranged so as to be located on or near the floor surface.

In order to cure the layer which is cured by ionizing radiation, it is preferable to reduce the oxygen concentration by nitrogen purging. The oxygen concentration is preferably 6% or less, and 4%
It is more preferably at most, and even more preferably at most 1%.

When the antireflection film of the present invention is used as one side of the surface protective film of a polarizer, the surface of the transparent support opposite to the surface on which the antireflection layer is formed may be saponified with alkali. is necessary. Specific means for the alkali saponification treatment can be selected from the following two. (1) is superior in that it can be processed in the same process as a general-purpose triacetyl cellulose film, but since the antireflection film surface is saponified, the surface is alkali-hydrolyzed and the film deteriorates. A problem may be that when the liquid remains, it becomes dirty. In that case, although it is a special step, (2) or (3) is excellent. (1) After the antireflection layer is formed on the transparent support, the back surface of the film is saponified by dipping it at least once in an alkaline solution. (2) Before the antireflection layer is formed on the transparent support. Alternatively, after that, an alkali solution is applied to the surface of the antireflection film opposite to the surface on which the antireflection film is formed, and then heated, washed with water and / or neutralized to saponify only the back surface of the film ( 3) By dipping the support in an alkaline solution at least once to saponify both sides and then form an antireflection layer

As the saponification treatment of (1) or (3),
It is preferable to perform saponification treatment with 1.0 to 2.5 N, 40 to 80 ° C. NaOH or KOH aqueous solution for 1 to 3 minutes, and 1.5 to 2.0 N, 40 to 60 ° C. NaOH or KOH aqueous solution. It is more preferable to perform saponification treatment for 1-2 minutes. Further, the saponification treatment of (2) includes 0.
5 ~ 2.0N NaOH or KOH aqueous solution #
Apply at 2 ~ # 5 bar, 5 ~ at film surface temperature 50 ~ 90 ° C
After treating for 30 seconds, it is preferable to wash with water and dry,
It is more preferable to apply 1.0 to 2.0 N NaOH or KOH aqueous solution with a # 3 to # 5 bar, treat at a film surface temperature of 50 to 70 ° C. for 5 to 20 seconds, and then wash with water and dry.

The antireflection film of the present invention, when used as one side of a surface protective film of a polarizer, is twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS). ), An optically compensated bend cell (OCB), and other modes of transmission type, reflection type, or semi-transmission type liquid crystal display device. Particularly for a liquid crystal display device of TN mode or IPS mode, as described in JP 2001-100043 A, an optical compensation film having a viewing angle widening effect is used as one of the two protective films on the front and back of the polarizer. By using on the surface opposite to the antireflection film of the present invention, a polarizing plate having an antireflection effect and a viewing angle widening effect can be obtained with the thickness of one polarizing plate, which is particularly preferable.

As the polarizing film, any polarizing film can be applied. For example, when a polyvinyl alcohol-based film is continuously supplied and the both ends of the film are stretched by applying tension while being held by the holding means, the locus of the holding means from the substantial holding start point to the substantial holding release point at one end of the film L1 and the locus L2 of the holding means from the substantial holding start point at the other end to the substantial holding release point have the relationship of the following equation (2) with respect to the distance W between the left and right substantial holding release points, and the left and right substantial The straight line connecting the holding start points shall be substantially orthogonal to the center line of the film introduced into the holding step, and the straight line connecting the left and right substantial holding release points should be substantially orthogonal to the center line of the film sent to the next step. And may be stretched (see US Patent Publication No. 2002-8840).
Formula (2) | L2-L1 |> 0.4W When used in a transmissive or semi-transmissive liquid crystal display device, a commercially available brightness enhancement film (polarization separation film having a polarization selection layer, such as Sumitomo 3M ( D-BEF manufactured by K.K.) can be used together with a display device having higher visibility. Further, by combining with a λ / 4 plate, it can be used as a surface protection plate for an organic EL display to reduce light reflected from the surface and inside. Furthermore, the antireflection layer of the present invention can be formed on a transparent support such as PET or PEN and applied to an image display device such as a plasma display panel (PDP) or a cathode ray tube display device (CRT).

[0055]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

<Preparation of support 1> (Preparation of fine particle dispersion a) Silica (Aerosil R972 manufactured by Nippon Aerosil Co., Ltd.) 0.67% by mass Cellulose acetate (Acetylated number 2 of hydroxyl groups of cellulose) .8) 2.93 mass% triphenyl phosphate 0.23 mass% biphenyldiphenyl phosphate 0.12 mass% methylene chloride 88.37 mass% methanol 7.68 mass% A solution was prepared and was prepared with an attritor. Dispersion was performed so that the volume average particle diameter was 0.7 μm, and a fine particle dispersion a was prepared.

(Preparation of Raw Material Dope) Cellulose triacetate (Number of acetylated hydroxyl groups of cellulose 2.8) 89.3% by mass Triphenyl phosphate 7.1% by mass Biphenyldiphenylphosphate 3.6% by mass 17.9 parts by mass of the fine particle dispersion a was added to 100 parts by mass of the solid content of 100% by mass, and a mixed solvent of methylene chloride 92% by mass methanol 8% by mass was appropriately added and dissolved by stirring to prepare a dope. The solid content concentration of the dope was (18.5)%.
The dope was filtered through a filter paper (Toyo Roshi Kaisha, Ltd., # 63), and then a sintered metal filter (Nippon Seisen Co., Ltd. 06) was used.
N, nominal pore diameter 10 μm), and then a mesh filter (RM manufactured by Nippon Pall Ltd., nominal pore diameter 45 μ).

(Preparation of Ultraviolet Absorber Solution b) 2 (2′-Hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole 5.83% by Mass 2 (2′-hydroxy- 3 ', 5'-di-tert-amylphenyl) benzotriazole 11.66% by mass Cellulose acetate (acetylated number of cellulose hydroxyl groups 2.8) 1.48% by mass triphenyl phosphate 10% by mass Biphenyldiphenylphosphate 0.05% by mass Methylene chloride 74.38% by mass Methanol 6.47% by mass An ultraviolet absorbent solution was prepared according to the above formulation, and filtered with an Astropore 10 filter manufactured by Fuji Photo Film Co., Ltd. To prepare an ultraviolet absorbent solution b.

(Preparation of Support 1) For the above dope,
Using a static mixer, the above ultraviolet absorbent solution b
The amount of the ultraviolet absorber is 1.04 with respect to the solid content in the dope.
While adjusting the content to be mass%, the dope was added and mixed in the piping route. This dope was cast on an endless support, dried with hot air until it had a self-supporting property, and peeled as a film. The residual solvent at the time of peeling was 21% by mass. This film was introduced into a tenter dryer, dried while holding both ends and applying tension, and the residual solvent was 9% by mass.
Dried until. Thereafter, it was dried in a roller drying zone until the residual solvent became 0.1% by mass. The film thickness of the completed support 1 was 40 μm, and its refractive index was 1.48.

<Preparation of Support 2> (Adjustment of Dope) 20 L stainless steel dissolving tank having a stirring blade (previously washed with methylene chloride)
To the above, the following mixed solvent was added, and the cellulose triacetate powder (average size 2 mm) was gradually added while stirring well, and the whole was charged to 10 kg. After the addition, the mixture is allowed to stand at room temperature (25 ° C.) for 3 hours to swell the cellulose triacetate, and the resulting non-uniform gel-like solution is cooled at −70 ° C. for 6 hours, then heated to 50 ° C. and stirred. I adjusted the dope. -Cellulose triacetate (number of acetylated hydroxyl groups of cellulose 2.8, viscosity average degree of polymerization 320) 20 parts by mass-methyl acetate 48 parts by mass-cyclopentanone 10 parts by mass-methanol 5 parts by mass-ethanol 5 Parts by mass Plasticizer A (dipentaerythritol hexaacetate) 5.5 parts by mass Plasticizer B (triphenyl phosphate) 6.5 parts by mass Fine particles (silica (particle size 20 nm)) 0.1 parts by mass UV Agent a: (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine 0.1 part by mass UV agent b : 2 (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole 0.1 parts by mass UV agent c: 2 (2'-hydroxy-3', 5'- The -Tert. - amyl phenyl) -5-chloro-benzotriazole 0.1 parts by mass _{· C 12 H 25 OCH 2 CH} 2 O-P (= O) - (OK) 2 0.05 parts by weight

(Preparation of Support 2) The obtained dope was mixed with 50
At 0 ° C., filtration was performed with a filter paper having an absolute filtration accuracy of 0.01 mm (# 63 manufactured by Toyo Roshi Kaisha, Ltd.), and an absolute filtration accuracy of 0.
It was filtered with 0025 mm filter paper (FH025, manufactured by Pall).

The filtered dope was cast on a glass plate so that the dry film thickness was 40 μm. Dry at 70 ° C for 3
After 5 minutes at 130 ° C. for 5 minutes, the film was peeled off from the glass plate and dried in stages at 160 ° C. for 30 minutes to evaporate the solvent, thereby preparing the support 2. The refractive index of this support was 1.49.

<Preparation of support 3> (Preparation of cellulose triacetate solution) Methyl acetate /
Cellulose triacetate (degree of substitution = 2.7, viscosity average degree of polymerization = 310) was gradually added (16% by weight) to a mixed solution of acetone / methanol (81/14/5;% by weight) while stirring well, It was left to swell at room temperature (25 ° C.) for 3 hours. The resulting swelling mixture was slowly stirred and cooled to -30 ° C at -8 ° C / min, then -70 ° C.
After cooling for 6 hours, the temperature was raised at + 8 ° C./min, and when the sol formation of the content had progressed to a certain extent, stirring of the content was started and heated to 50 ° C. to obtain a dope. The cellulose triacetate dope contains silica particles (particle size 20
nm), triphenyl phosphate / biphenyl diphenyl phosphate (1/2), 2,4-bis- (n
-Octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine was added to each of 0.5% by mass of cellulose acylate and 1
0 mass% and 1.0 mass% were added.

(Adjustment of Filler-Filled Cellulose Triacetate Dope) Alumina having a particle size of about 13 nm (Nippon Aerosil Co., Ltd.) was used so that the filler concentration in the cellulose triacetate was 5% by volume and the treatment amount of the surface modifier was 10% by weight. Made of aluminum oxide C) and CH ₃ COO
(C ₅ H ₁₀ COO) ₂ H was added to a mixed solution of methyl acetate / acetone / methanol (81/14/5; mass%),
A liquid dispersed by a sand grinder mill using glass beads was prepared, added to the above cellulose triacetate dope, and further shear-mixed with a kneader to prepare a filler-filled dope.

Then, the obtained dope was filtered at 50 ° C. with an absolute filtration accuracy of 0.01 mm (# 6 manufactured by Toyo Roshi Kaisha, Ltd.).
It was filtered with 3) and further filtered with a filter paper (FH025, manufactured by Pall) with an absolute filtration accuracy of 0.0025 mm.

(Preparation of Support 3) The solution was cast into a band shape using a band casting machine having an effective length of 6 m, and after drying, the film was peeled from the band. Further, it was dried in an environment of 120 ° C. for 30 minutes and the solvent was evaporated to obtain a cellulose acylate film. The film thickness was adjusted to 40 μm. The refractive index of this support was 1.50.

(Preparation of coating liquid A for hard coat layer) 306 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 51 parts by mass of methyl ethyl ketone and 148 It was dissolved in a mixed solvent of parts by mass of methyl isobutyl ketone. After adding 7.5 parts by mass of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) to the obtained solution and stirring until dissolved, 450 parts by mass of MIBK-ST (average particle size 10 to 20 nm, solid content). A methyl isobutyl ketone dispersion of SiO ₂ sol having a concentration of 30% by mass, manufactured by Nissan Kagaku Co., Ltd. was added and the mixture was stirred to obtain a polypropylene filter having a pore size of 3 μm (PPE).
-03) was filtered to prepare a coating liquid A for hard coat layer.

(Preparation of Hard Coat Layer Coating Liquid B) 1000 parts by mass of the above hard coat layer coating liquid A (refractive index after solvent drying and UV curing: 1.51) had an average particle size of 1.
Particles with forward scattering property made of 3 μm cross-linked polystyrene (SX-130H, refractive index: 1.61, Soken Chemical Co., Ltd.)
(Manufactured) 150 parts by mass is added, and 10 parts are added with an air dispersion.
The mixture was stirred for a minute to obtain a mixture, and the mixture was filtered through a polypropylene filter (PPE-03) having a pore size of 3 μm to prepare a coating solution B for hard coat layer having forward scattering property.

(Preparation of coating liquid C for hard coat layer) 306 parts by weight of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 16 parts by weight of methyl ethyl ketone and 220 It was dissolved in a mixed solvent of parts by mass of cyclohexanone. After adding 7.5 parts by mass of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) to the obtained solution and stirring until dissolved, 450 parts by mass of ME was added.
K-ST (average particle size 10 to 20 nm, methyl ethyl ketone dispersion of SiO ₂ sol having a solid content concentration of 30% by mass, manufactured by Nissan Kagaku Co., Ltd.) was added and stirred to obtain a mixture having a pore size of 3
A coating liquid C for the hard coat layer was prepared by filtering with a polypropylene filter (PPE-03) having a thickness of μm.

(Preparation of titanium dioxide dispersion) Ultrafine titanium dioxide particles (TTO-55B, manufactured by Ishihara Sangyo Co., Ltd.) 25
0 g, crosslinking reactive group-containing anionic polymer (Chemical Formula 2) 3
7.5 g, cationic monomer (DMAEA, Kojin Co., Ltd.)
2.5 g of cyclohexanone and 710 g of cyclohexanone were dispersed by Dynomill to prepare a titanium dioxide dispersion liquid having a mass average diameter of 65 nm.

[0071]

[Chemical 2]

(Preparation of Coating Solution for Medium Refractive Index Layer) A mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was added to 155.2 g of the above titanium dioxide dispersion.
89.5 g, photopolymerization initiator (IRGACURE 907, manufactured by Ciba-Geigy Co., Ltd.) 4.68 g, photosensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.56 g, methyl ethyl ketone 770.4 g, and cyclohexanone 2983.0 g was added and stirred. A polypropylene filter having a pore size of 0.4 μm was filtered to prepare a coating solution for the medium refractive index layer.

(Preparation of coating liquid for high refractive index layer) A mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was added to 985.7 g of the above titanium dioxide dispersion.
48.8 g, acrylic-containing silane coupling agent 33.
5 g (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), photopolymerization initiator (Irgacure 907, manufactured by Nippon Ciba-Geigy Co., Ltd.) 4.03 g, photosensitizer (Kayacure DET)
X, manufactured by Nippon Kayaku Co., Ltd.) 1.35 g, methyl ethyl ketone 622.5 g, and cyclohexanone 1865.0
g and stirred. The coating liquid for the high refractive index layer was prepared by filtering with a polypropylene filter having a pore size of 0.4 μm.

(Preparation of coating liquid for low refractive index layer) Refractive index 1.
42 thermally crosslinkable fluorine-containing polymer (OPSTAR JN72
28, solid content concentration 6% by mass, manufactured by JSR Corporation, 93.0
g of silica fine particles in methyl ethyl ketone dispersion (MEK
-ST, solid content concentration 30% by mass, manufactured by Nissan Chemical Co., Ltd.
8.0 g, acrylic group-containing silane coupling agent 8.0
g (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 100.0 g of methyl ethyl ketone and 5.0 g of cyclohexanone were added and stirred. The coating liquid for the low refractive index layer was prepared by filtering with a polypropylene filter having a pore size of 1 μm.

Example 1 (Preparation of Antireflection Film) On the support 1 having a thickness of 40 μm prepared above, the above coating solution A for hard coat layer was formed.
Was applied using a gravure coater and dried at 100 ° C. for 2 minutes. Next, the coating layer is cured by irradiating with ultraviolet rays, and the hard coat layer (refractive index: 1.51, film thickness: 6μ
m) was formed. Subsequently, the above-mentioned coating liquid for a medium refractive index layer was applied using a gravure coater, dried at 100 ° C., and then irradiated with ultraviolet rays to cure the coating layer, and the medium refractive index layer (refractive index: 1.63 , Film thickness: 67 nm). The above-mentioned coating liquid for high refractive index layer was applied onto the medium refractive index layer using a gravure coater, dried at 100 ° C., and then irradiated with ultraviolet rays to cure the coating layer, and the high refractive index layer (refractive index rate:
1.90, film thickness: 107 nm). Furthermore, the coating liquid for a low refractive index layer was applied onto the high refractive index layer using a gravure coater, and the coating layer was cured at 120 ° C. for 8 minutes to obtain a low refractive index layer (refractive index: 1.43 , Film thickness: 86 nm
) Is provided. In this way, antireflection film A was prepared. Further, antireflection films B and C were prepared in the same manner as the antireflection film A except that the supports 2 and 3 having a thickness of 40 μm prepared above were used as the support.

(Evaluation of Antireflection Film) The obtained film was evaluated for the following items. (1) The specular reflectance and tint spectrophotometer V-550 (manufactured by JASCO Corporation) was equipped with an adapter ARV-474, and an emission angle of -5 at an incident angle of 5 ° in a wavelength range of 380 to 780 nm. The specular reflectance was measured, the average reflectance from 450 to 650 nm was calculated, and the antireflection property was evaluated. Further, from the measured reflection spectrum, CIE1976L * a showing the tint of specular reflection light with respect to the 5 degree incident light of the CIE standard light source D65.
The L * value, a * value, and b * value in the * b * color space were calculated, and the tint of the reflected light was evaluated. (2) Pencil hardness evaluation As an index of scratch resistance, the pencil hardness evaluation described in JIS K 5400 was performed. Anti-reflection film temperature 25 ℃, humidity 60
After conditioning the humidity for 2 hours at% RH, using a test pencil of 2H to 5H defined in JIS S 6006, the load is 500 g, the evaluation is as follows, and the highest hardness that is OK is evaluated. Value. No scratches to one scratch in the evaluation of n = 5: OK Three or more scratches in the evaluation of n = 5: NG (3) Smoothness evaluation The evaluation was made according to the following judgments. Line-shaped defects cannot be visually recognized: ○ Line-shaped defects can be visually recognized: ×

Comparative Example 1 A comparative antireflection film was prepared in the same manner as the antireflection film A except that a triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm was used. It was created and evaluated in the same manner as in Example 1.

Comparative Example 2 An antireflection film for comparison was prepared in the same manner as in Example 1 except that the coating liquid C for the hard coat layer was used instead of the coating liquid A for the hard coat of the antireflection film A. Then, the same evaluation as in Example 1 was performed.

The antireflection films A, B and C are the same as Comparative Example 1.
The anti-reflection film of is about 80 μm, while about 4
It was possible to reduce the thickness to 0 μm. Further, the antireflection film of Comparative Example 2 has a smoothness evaluation of x, while the antireflection films A, B, and C are all good because the solvent of the coating liquid for the hard coat layer does not attack the support. Met. Further, the antireflection films A, B, and C all have an average reflectance of 0.28%, a * = 2, and b * = − 6, and both low reflectance and reduction of tint are compatible, and highly preferable reflection. Have characteristics. Furthermore, the pencil hardness is 3H for antireflection films A and B,
The antireflection film C is as high as 4H and is hard to be scratched.

[Example 2] The antireflection film A was prepared in the same manner as in 2.
Iodine is adsorbed to polyvinyl alcohol by a film in which the triacetyl cellulose surface on the back side of the film is saponified by immersing it in a 0N, 55 ° C NaOH aqueous solution for 2 minutes, and a film in which the support 1 is saponified under the same conditions. Then, both sides of the polarizer prepared by stretching are adhered and protected, and the polarizer A
It was created. Further, the antireflection film A was saponified by applying a 1.0 N KOH aqueous solution to the back surface of the antireflection film with a # 3 bar, treated at a film surface temperature of 60 ° C. for 10 seconds, then washed with water and dried. Using the film
Polarizing plate B was prepared in the same manner. The polarizing plates A and B are liquid crystal display devices of a notebook computer equipped with a transmissive TN liquid crystal display device such that the antireflection film side is the outermost surface (D manufactured by Sumitomo 3M Co., Ltd., which is a polarization separation film having a polarization selection layer). −
When a BEF having a BEF between the backlight and the liquid crystal cell) was replaced with the polarizing plate on the viewing side, a display device having a very low display quality and a very high display quality was obtained.

[Comparative Example 3] In the polarizing plate A, instead of the antireflection film A and the support 1, the antireflection film of Comparative Example 1 and a triacetyl cellulose film having a thickness of 80 μm (TAC-TD80U, Fuji Photo Film) were used. (stock)
A polarizing plate was prepared in the same manner as the polarizing plate A, except that

The polarizing plates A and B could be thinned to about 160 μm, while the polarizing plate of Comparative Example 3 had a thickness of about 230 μm. In addition, it had excellent smoothness and had very preferable reflection characteristics.

[Example 3] As a protective film on the liquid crystal cell side of the polarizing plate on the viewing side of the transmissive TN liquid crystal cell to which the antireflection film A was attached and a protective film on the liquid crystal cell side of the polarizing plate on the backlight side, The disc surface of the discotic structural unit is inclined with respect to the transparent support surface, and the angle formed by the disc surface of the discotic structural unit and the transparent support surface changes in the depth direction of the optically anisotropic layer. When a viewing angle widening film having an optical compensation layer (Wide View Film SA-12B, manufactured by Fuji Photo Film Co., Ltd.) was used, the contrast in a bright room was excellent, and the viewing angles in the vertical and horizontal directions were very wide, A liquid crystal display device having extremely high visibility and high display quality was obtained.

Example 4 A forward scattering function was obtained in the same manner as in antireflection film A except that coating liquid B for hard coat layer was used instead of coating liquid A for hard coat of antireflection film A of Example 1. Was prepared in the same manner as in Example 3, and the forward scattering antireflection film was formed on the outermost surface side, and the viewing angle widening film wide view film (WV-12A, Fuji Photo Film ( A transparent type TN liquid crystal display device was prepared in which a polarizing plate having a product manufactured by K.K. In the liquid crystal display device thus manufactured, the limit angle at which gradation inversion occurs when the viewing angle is tilted downward is improved from 40 degrees to 60 degrees as compared with Example 3, and the visibility and display quality are improved. It was very good at.

[Example 5] The antireflection film A prepared in Example 1 was adhered to a glass plate on the surface of an organic EL display device with an adhesive, whereby reflection on the glass surface was suppressed and visibility was improved. A high-quality display device was obtained.

Example 6 A glass plate on the surface of an organic EL display device was prepared by laminating a λ / 4 plate on the opposite surface of the polarizing plate having the antireflection film A on one surface to the side having the antireflection film. When it was attached to, the surface reflection and the reflection from the inside of the surface glass were cut, and a display with extremely high visibility was obtained.

Example 7 A polarizing plate was prepared in the same manner as the polarizing plate A of Example 2 except that the polarizer prepared by adsorbing iodine on polyvinyl alcohol and stretching was replaced with the polarizer prepared by the following method. Created. The PVA film was dipped in an aqueous solution containing 5.0 g / l iodine and 10.0 g / l potassium iodide at 25 ° C. for 90 seconds, and further dipped in an aqueous solution containing 10 g / l boric acid at 25 ° C. for 60 seconds. Public 20th
It was introduced into the tenter stretching machine of the form of No. 02-8840A1 shown in Fig. 2, once stretched to 7.0 times and then shrunk to 5.3 times, and after that, the width was kept constant and after drying at 70 ° C, the tenter was used. I left. The difference in transport speed between the left and right tenter clips is less than 0.05%, and the angle between the center line of the film introduced and the center line of the film sent to the next step is 0.
It was °. Here, both | L1-L2 | and W were 0.7 m. Wrinkles and film deformation at the tenter exit were not observed. The absorption axis direction of the obtained polarizing plate was inclined by 45 ° with respect to the longitudinal direction. 550n of this polarizing plate
The transmittance at m is 43.3% and the polarization degree is 99.98%.
Met. It was possible to obtain a thin polarizing plate with an antireflection function, which has good area efficiency and whose absorption axis is inclined by 45 ° with respect to the side.

[0088]

INDUSTRIAL APPLICABILITY The antireflection film of the present invention can form an antireflection layer while maintaining the smoothness of the surface of a support even when a cellulose acylate having a thin thickness, which has not been heretofore used, is used as the support. Therefore, the deterioration of visibility due to the reflection of external light can be prevented at a high level. Further, even when a high-luminance light source such as a fluorescent lamp on the back of the user who faces the display is reflected on the display surface, it is not colored in reddish purple or bluish purple, and the display quality is not significantly deteriorated. When this is applied to a polarizing plate and arranged in a display device such as a liquid crystal display device, a thin liquid crystal display device having excellent visibility is obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing a specific example of an antireflection film of the present invention.

[Explanation of symbols]

1 support 2 Hard coat layer 3 Middle refractive index layer 4 High refractive index layer 5 Low refractive index layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme coat (reference) G02F 1/1335 520 G02B 1/10 AF term (reference) 2H049 BA02 BA27 BB33 BB43 BB65 BC22 2H091 FA08X FA08Z FA37X FB02 FB08 FB13 FC01 FC07 FC22 FC24 FC30 HA06 HA07 HA09 HA10 KA01 KA02 KA10 LA02 LA11 LA16 LA17 LA18 LA19 LA20 2K009 AA06 AA15 BB28 CC03 CC26 CC42 DD02 4F100 AA20 AJ05A AK17 AK21 AK25 AR00A BA30 BAYY GB90 JN90

Claims (4)

[Claims] 1. An antireflection film having a constitutional layer containing an antireflection layer on a support made of cellulose acylate, wherein the thickness of the support is 10 to 70 μm, and the layer in contact with the support is one of the constitutional layers. An antireflection film formed from a coating solution containing a solvent that does not dissolve the support. 2. In a method for producing an antireflection film, which comprises coating a constituent layer containing an antireflection layer on a support made of cellulose acylate, the thickness of the support is 10 to 70 μm.
And a method for producing an antireflection film, which comprises the steps of coating a coating solution containing a solvent that does not dissolve the support on the support and drying the coating. 3. A polarizing plate comprising the antireflection film according to claim 1 as a protective film on at least one surface. 4. At least one polarizing plate according to claim 3.
Image display device having one sheet.