JP2006215096A - Antireflection film, polarizing plate using the same and image display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection film having low moisture permeability, excellent in scratch resistances, antireflection effect, curl, and antifouling property, a polarizing plate using the antireflection film, and an image display unit. <P>SOLUTION: The antireflection film is obtained by laminating at least a low-moisture-permeability hardened layer and a low-refractive-index layer in this order on a transparent base film, and moisture permeability of the antireflection film measured according to JIS-Z-0208 in an atmosphere at 60°C and 95% RH is ≤1,000 g/m<SP>2</SP>×day. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device such as an antireflection film, a polarizing plate, and a liquid crystal display device (hereinafter referred to as LCD).

  Anti-reflection films are generally used in display devices such as cathode ray tube display (CRT), plasma display (PDP), electroluminescence display (ELD), and liquid crystal display (LCD) to reduce contrast and reflect images. In order to prevent engraving, it is placed on the outermost surface of the display so as to reduce reflectivity using the principle of optical interference.

  Such an antireflection film has a low refractive index layer having an appropriate film thickness on the outermost surface on the support, and optionally a high refractive index layer, a medium refractive index layer, between the support and the low refractive index layer, It can be produced by forming a hard coat layer or the like. In order to realize a low reflectance, a material having a refractive index as low as possible is desired for the low refractive index layer. Further, since the antireflection film is used on the outermost surface of the display, a function as a protective film of the image display device is expected. It is required that dirt and dust are difficult to adhere and that scratch resistance is strong.

In order to lower the refractive index of the low refractive index layer, there are means of introducing an organic group containing a fluorine atom into the binder or lowering the density (introducing voids). When an organic group containing a fluorine atom is used for the binder, the cohesive force of the binder itself is reduced, and there is a limit in reducing the refractive index practically by introducing a necessary linking group to compensate for it. It was difficult to make it 1.40 or less. On the other hand, the method of reducing the refractive index by introducing microscopic voids in the low refractive index layer can be less than 1.40, but the film strength is weak, and defects such as fingerprints and oil are liable to enter. was there.
For example, Patent Documents 1 to 3 attempt to reduce the refractive index by forming microvoids in the binder. Patent Document 4 has an attempt to lower the refractive index using porous silica. None of these were practically satisfactory in terms of film strength, fingerprint contamination, and the like.
Patent Documents 5 to 9 describe an antireflection film containing hollow silica particles in a low refractive index layer.

  On the other hand, when the antireflection film is used for a cathode ray tube display (CRT), a plasma display (PDP), an electroluminescence display (ELD), or a liquid crystal display (LCD), the curling process is performed when the antireflection film remains. Will cause trouble. Therefore, it is desired that the curl of the antireflection film is small.

  Since LCD TVs are often in use for a long time at all times, the mounted polarizing plate is susceptible to physical damage, and if it is damaged, the display image quality is impaired. Strengthening of is desired. Furthermore, long-term durability has been demanded so that the image quality of the LCD does not deteriorate even when used for a long time in an environment having temperature and humidity changes.

  In the polarizing plate, a protective layer is generally bonded to both surfaces or one surface of a polarizer having polarizing ability via an adhesive layer. Polyvinyl alcohol (hereinafter referred to as PVA) is mainly used as a material for the polarizer, and the PVA film is stretched uniaxially and then dyed with iodine or a dichroic dye, or stretched and then boron. A polarizer is formed by crosslinking with a compound. As the protective layer, cellulose triacetate (hereinafter referred to as TAC) is mainly used because it is optically transparent and has low birefringence and a smooth surface.

However, when cellulose triacetate is used as a protective layer, there has been a problem that the polarizing performance of the polarizer deteriorates under a long-term high-temperature and high-humidity environment.
JP-A-6-3501 JP-A-9-222502 Japanese Patent Laid-Open No. 9-222503 JP 7-48527 A JP 2001-233611 A JP 2002-79616 A JP 2002-317152 A JP 2003-202406 A JP 2003-292831 A

An object of the present invention is to provide an antireflection film having low moisture permeability and excellent scratch resistance and antireflection effect. Furthermore, an object of the present invention is to provide an antireflection film excellent in curling and antifouling properties in addition to the above characteristics.
Another object of the present invention is to provide a polarizing plate and an image display device provided with the antireflection film.

As a result of intensive studies, the present inventors have found that the above-described problems can be solved by the present invention described below.
(1) Moisture permeability measured in an atmosphere of 60 ° C. and 95% relative humidity according to JIS-Z-0208, at least a low moisture permeability cured layer and a low refractive index layer are laminated in this order on a transparent substrate film. Is 1000 g / m ² · day or less.
(2) The antireflection film as described in (1) above, wherein the refractive index of the low refractive index layer is 1.46 or less.
(3) The low moisture permeability cured layer is
A curable composition containing at least one compound selected from the compound represented by the following general formula (A) and the compound represented by the following general formula (B) is coated and dried on a transparent substrate film, The antireflection film as described in (1) or (2) above, which is obtained by curing this.
Formula (A)

（式中Ｒ１は水素原子または炭素数１〜３のアルキル基、Ｒ２は炭素数１〜５のアルキレン基またはアルキレンオキサイド基、Ｒ３は水素原子または炭素数１〜３のアルキル基、ｎは１または２の整数）
一般式（Ｂ）

(Wherein R1 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R2 is an alkylene group or alkylene oxide group having 1 to 5 carbon atoms, R3 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n is 1 or An integer of 2)
General formula (B)

（式中Ｒ１、Ｒ３およびｎは上記一般式（Ａ）と同じ意味である）
（４）前記低屈折率層が、フッ化アルキル部を有する成分と、粒子サイズが２０〜１００ｎｍであり、屈折率が１．４０以下である中空シリカ微粒子を含有することを特徴とする上記（１）〜（３）のいずれかに記載の反射防止フィルム。
（５）前記低屈折率層が、ジアルキルシロキサン部を有する成分と、粒子サイズが２０〜１００ｎｍであり、屈折率が１．４０以下である中空シリカ微粒子を含有することを特徴とする上記（１）〜（４）のいずれかに記載の反射防止フィルム。
（６）前記透明基材フィルムがセルロースアシレート類であることを特徴とする上記（１）〜（５）のいずれかに記載の反射防止フィルム。
（７）前記セルロースアシレート類が、セルロースアセテート、セルロースアセテートプロピオネート、またはセルロースアセテートブチレートであることを特徴とする上記（１）〜（６）のいずれかに記載の反射防止フィルム。
（８）前記低透湿性硬化層の膜厚が１〜１０μｍであることを特徴とする上記（１）〜（７）のいずれかに記載の反射防止フィルム。
（９）上記（１）〜（８）のいずれかに記載の反射防止フィルムを偏光子の保護層として用いたことを特徴とする偏光板。
（１０）上記（９）に記載の偏光板を有することを特徴とする画像表示装置。

(Wherein R1, R3 and n have the same meaning as in the above general formula (A))
(4) The above, wherein the low refractive index layer contains a component having an alkyl fluoride part, and hollow silica fine particles having a particle size of 20 to 100 nm and a refractive index of 1.40 or less ( The antireflection film according to any one of 1) to (3).
(5) The above-mentioned (1), wherein the low refractive index layer contains a component having a dialkylsiloxane part and hollow silica fine particles having a particle size of 20 to 100 nm and a refractive index of 1.40 or less. ) To (4).
(6) The antireflection film as described in any one of (1) to (5) above, wherein the transparent substrate film is a cellulose acylate.
(7) The antireflection film as described in any one of (1) to (6) above, wherein the cellulose acylates are cellulose acetate, cellulose acetate propionate, or cellulose acetate butyrate.
(8) The antireflection film as described in any one of (1) to (7) above, wherein the low moisture-permeable cured layer has a thickness of 1 to 10 μm.
(9) A polarizing plate using the antireflection film according to any one of (1) to (8) as a protective layer of a polarizer.
(10) An image display device comprising the polarizing plate according to (9).

Since the antireflection film of the present invention has a low moisture permeability cured layer and a low refractive index layer on a transparent substrate film, it has low moisture permeability and is excellent in scratch resistance and antireflection effect. In addition to the above properties, the antireflection film of the present invention has small curl and excellent antifouling properties.
The polarizing plate comprising the antireflection film of the present invention as a protective layer has excellent high temperature and humidity durability, and can maintain the display image quality of a display such as a liquid crystal display device (hereinafter referred to as LCD) for a long period of time. . When the antireflection film of the present invention is not applied as a protective layer for a polarizer, but is bonded to the surface of a cathode ray tube display (CRT), plasma display (PDP), electroluminescence display (ELD) or liquid crystal display (LCD). Since the curl is small, the workability is remarkably improved, which is useful.

In the antireflection film of the present invention, at least a low moisture permeability cured layer and a low refractive index layer are laminated in this order on a transparent substrate film, and in an atmosphere of 60 ° C. and 95% relative humidity in accordance with JIS-Z-0208. The measured moisture permeability is 1000 g / m ² · day or less.

[Low moisture permeability cured layer]
Hereinafter, the low moisture-permeable cured layer used for the functional film of the present invention will be described in detail. In the present specification, the description “(meth) acryloyl” represents the meaning of “at least one of acryloyl and methacryloyl”. The same applies to “(meth) acrylate”, “(meth) acrylic acid” and the like. In addition, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”.

The low moisture-permeable cured layer in the present invention preferably contains a hydrophobic portion, and has an I / O value (Yoshio Koda, “Organic Conceptual Diagram-Fundamentals and Applications”, Sankyo Publishing (1984)) of 0.8 or less, The cured layer preferably comprises 0.7 or less, more preferably 0.6 or less polymerized units.
The low moisture-permeable cured layer most preferably includes a polymer unit derived from at least one compound selected from the group of compounds represented by formulas (A) and (B). It is presumed that the alicyclic structure contained in the structure of the polymerized unit has the effect of reducing the moisture permeability.

  In general formula (A) and general formula (B), R1 represents a hydrogen atom or a C1-C3 alkyl group, Preferably, a hydrogen atom, a methyl group, and an ethyl group are represented. R2 represents an alkylene group having 1 to 5 carbon atoms or an alkylene oxide group, preferably a methylene group, an ethylene group, a methylene oxide group, or an ethylene oxide group. R3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and preferably represents a hydrogen atom, a methyl group, or an ethyl group.

  Although the preferable specific example of a compound represented by general formula (A) is shown, this invention is not limited to these.

  Preferable specific examples of the compound represented by formula (B) are shown below, but the present invention is not limited thereto.

  The compounds represented by the general formulas (A) and (B) are described in JP-A-60-152515.

The curable composition used for forming the low moisture-permeable cured layer in the antireflection film of the present invention contains the following polymerizable compound in addition to the compounds represented by the general formulas (A) and (B). Can do.
For example, as a compound having two or more ethylenically unsaturated groups, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxytri (meta) ) Acrylate, ditrimethylolpropane tetra (meth) acrylate, glycene polypropoxytri (meth) acrylate, di (meth) acrylate of ε-caprolactone adduct of hydroxypenic acid neopenglycol (eg Nippon Kayaku Co., Ltd.) KAYARAD HX-220, HX-620, etc.), pentaerythritol tetra (meth) acrylate, poly (meth) acrylate of dipentaerythritol and ε-caprolactone reaction product, dipentaerythritol Hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol octa (meth) acrylate, tripentaerythritol hepta (meth) acrylate, polyglycidyl compounds (polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1 , 6-hexanediol diglycidyl ether, hexahydrophthalic acid diglycidyl ester, glycerin polyglycidyl ether, glycerin polyethoxyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolpropane polyethoxypolyglycidyl ether, etc.) and (meth) Epoxy (meth) acrylate, which is a reaction product of acrylic acid, and polyfunctional (meth) acrylate containing hydroxyl group And polyisocyanate compounds (tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate) , P-phenylene diisocyanate, etc.) and a polyfunctional urethane acrylate. You may use these individually or in mixture of 2 or more types.

  Furthermore, as vinyl monomers, esters derived from acrylic acid or α-alkylacrylic acid (for example, methacrylic acid), or amides (for example, Ni-propylacrylamide, Nn-butylacrylamide, N- t-butylacrylamide, N, N-dimethylacrylamide, N-methylmethacrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylamidopropyltrimethylammonium chloride, methacrylamide, diacetone acrylamide, acryloylmorpholine, N-methylol Acrylamide, N-methylol methacrylamide, methyl acrylate, ethyl acrylate, hydroxyethyl acrylate, n-propyl acrylate, i-propyl acrylate 2-hydroxypropyl acrylate, 2-methyl-2-nitropropyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, t-pentyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-methoxymethoxyethyl acrylate, 2,2,2-trifluoroethyl acrylate, 2,2-dimethylbutyl acrylate, 3-methoxybutyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, n-pentyl acrylate, 3-pentyl acrylate , Octafluoropentyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, cyclopentyl acrylate, cetyl acrylate, benzyl acrylate Benzyl methacrylate, methoxypolyethylene glycol methacrylate, n-octyl acrylate, 2-ethylhexyl acrylate, 4-methyl-2-propylpentyl acrylate, heptadecafluorodecyl acrylate, n-octadecyl acrylate, methyl methacrylate, 2,2,2 -Trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, hexafluoropropyl methacrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, sec-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate , 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate Benzyl methacrylate, heptadecafluorodecyl methacrylate, n-octadecyl methacrylate, 2-isobornyl methacrylate, 2-norbornylmethyl methacrylate, 5-norbornen-2-ylmethyl methacrylate, 3-methyl-2-norbol Nylmethyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentanyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentanyl methacrylate, pentamethylpiperidyl methacrylate, tetramethylpiperidyl methacrylate, dimethylaminoethyl methacrylate, etc. ), Acrylic acid or α-alkyl acrylic acid (acrylic acid, methacrylic acid, itaconic acid, etc.),

  Vinyl esters (eg, vinyl acetate), esters derived from maleic acid or fumaric acid (dimethyl maleate, dibutyl maleate, diethyl fumarate, etc.), maleimides (N-phenylmaleimide, etc.), maleic acid, fumaric acid , Sodium salt of p-styrenesulfonic acid, acrylonitrile, methacrylonitrile, dienes (eg butadiene, cyclopentadiene, isoprene), aromatic vinyl compounds (eg styrene, p-chlorostyrene, t-butylstyrene, α-methyl) Styrene, sodium styrenesulfonate), N-vinylpyrrolidone, N-vinyloxazolidone, N-vinylsuccinimide, N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methyl Cetamide, 1-vinylimidazole, 4-vinylpyridine, vinyl sulfonic acid, sodium vinyl sulfonate, sodium allyl sulfonate, sodium methallyl sulfonate, vinylidene chloride, vinyl alkyl ethers (eg methyl vinyl ether), ethylene, propylene, 1 -Butene, isobutene, etc. are mentioned. Two or more of these vinyl monomers may be used in combination. Vinyl monomers other than these are listed in Research Disclosure No. 1955 (1980, July), JP-A-63-243108, high performance liquid polymer material (Maruzen Co., Ltd., issued on May 20, 1990) Chapter 14 may be used. it can. In the present invention, esters derived from acrylic acid or methacrylic acid, amides, and aromatic vinyl curable resins are particularly preferably used vinyl monomers.

  The compound having two or more ethylenically unsaturated groups and the vinyl monomer are from Nippon Kayaku Co., Ltd. under the trade name of KAYARAD, and from Daiichi Kogyo Seiyaku Co., Ltd. under the trade name of New Frontier. It can be obtained under the trade name of Aronix from Co., Ltd. and under the trade name of Funkrill from Hitachi Chemical Co., Ltd.

  The amount of the compound having two or more ethylenically unsaturated groups or the vinyl monomer added to the compound represented by the general formulas (A) and (B) is the required moisture permeability, pencil hardness, refractive index, and transparency. The total mass of the compound of the general formulas (A) and (B), the compound having two or more ethylenically unsaturated groups, and the vinyl monomer can be selected depending on the properties, adhesion to the polarizer, etc. On the other hand, the mass of the compound having two or more ethylenically unsaturated groups and / or the vinyl monomer is preferably 70% by mass or less, more preferably 50% by mass or less, and most preferably 30% by mass or less.

<Initiator>
In order to obtain a low moisture-permeable cured layer, the curable composition contains a polymerization initiator.
(I) When performing heat curing, benzoyl peroxide, dicumyl peroxide, or the like is added.
(Ii) Add benzoyl peroxide / dimethylaniline, cumene hydroperoxide / vanadium accelerator, etc. when performing redox system room temperature curing.
(Iii) In the case of anaerobic curing, hydroperoxide / tertiary amine / sulfimide is added.
(Iv) In the present invention, ultraviolet curing is most preferred and will be described in detail.

  Examples of polymerization initiators that generate radicals by ultraviolet rays include known radical generators such as acetophenones, benzophenones, Michler's ketone, benzoylbenzoate, benzoins, α-acyloxime esters, tetramethylthiuram monosulfide, and thioxanthone. Can be used. In general, sulfonium salts and iodonium salts used as photoacid generators also act as radical generators upon irradiation with ultraviolet rays, and these may be used alone in the present invention. In addition to a polymerization initiator, a sensitizer may be used for the purpose of increasing sensitivity. Examples of the sensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, and thioxanthone derivatives.

  The addition amount of the polymerization initiator is preferably 0.1 to 15% by mass based on the total mass of the ethylenically unsaturated group-containing curable resin contained in the curable composition, preferably 1 to More preferably, it is used in the range of 10% by mass.

  In addition, the metal oxide used by the hard-coat layer mentioned later can be introduce | transduced into a low moisture-permeable cured layer, and a low moisture-permeable cured layer can also serve as a high refractive index layer.

  After applying and drying a curable composition containing at least one compound selected from the compounds represented by the general formula (A) or (B) and an initiator on the transparent base film, the low moisture-permeable cured layer is applied. It can be formed by curing by a method such as heat curing, redox system room temperature curing, anaerobic curing or ultraviolet curing.

[Low refractive index layer]
Hereinafter, preferred low refractive index layers in the present invention will be described in detail.
<Introduction of fine pores into the antireflection film constituent layer>
In the present invention, in order to sufficiently lower the refractive index of the low refractive index layer, it is preferable to introduce fine vacancies in the layer, and there is no particular limitation on the method, but for example, bubbles are generated in the layer. Fixing the binder by curing, a method of using voids formed between the particles that are introduced into the layer, a method of introducing porous fine particles into the layer, a hollow fine particle The method to introduce | transduce etc. can be mentioned. From the viewpoint of production stability and the like, the method of introducing porous fine particles into the layer and the method of introducing hollow fine particles are preferable.

In the hollow fine particles, the void ratio x is expressed by the following formula (1), where r _{i is} the radius of the cavity in the particle and r _o is the radius of the particle outer shell.
Formula (1): x = (r _i / r _o ) ³ × 100 (%)
The porosity of the hollow fine particles is preferably 10 to 60%, more preferably 20 to 60%, and most preferably 30 to 60%. It is preferable that the void ratio of the hollow fine particles be in the above range from the viewpoint of lowering the refractive index and maintaining the durability of the particles.

<Method for preparing pore-containing fine particles>
When these pore-containing fine particles (porous or hollow fine particles) are used, the structure and type are not limited, but porous inorganic oxide fine particles, hollow organic polymer latex or hollow inorganic oxide It is preferable to use solid particles, and it is more preferable to use hollow organic polymer latex or hollow inorganic oxide fine particles. When inorganic oxide fine particles are used, fine particles mainly composed of aluminum oxide, silicon oxide, and tin oxide are preferable. The main component refers to a component having a content of 80% by mass or more among the components constituting the fine particles. In the present invention, it is preferable to use hollow silica fine particles.
A preferred method for producing hollow fine particles comprises the following steps. The first step is the formation of core particles that can be removed by post-treatment, the second step is the formation of a shell layer, the third step is the dissolution of core particles, and the fourth step is the formation of an additional shell phase if necessary. Specifically, the production of hollow fine particles can be performed in accordance with the method for producing hollow silica fine particles described in, for example, JP-A-2001-233611.
A preferred method for producing porous fine particles is to produce porous core particles by controlling the degree of hydrolysis and condensation of alkoxide and the type and amount of coexisting substances as the first step, and a shell layer on the surface as the second step. It is a method of forming. Specifically, the production of porous particles can be performed by the methods described in JP-A Nos. 2003-327424, 2003-335515, 2003-226516, 2003-238140, and the like. it can.

<Measurement of particle size of pore-containing fine particles>
In the measurement of the size of the pore-containing fine particles of the present invention, the particles were observed with a transmission electron microscope, and the equivalent circle diameter was calculated as an average of 1,000 particles. The diameter is preferably 20 to 100 nm, more preferably 35 to 100 nm, and most preferably 45 to 80 nm. If the particle size is too small, an increase in the refractive index and an increase in the amount of adsorbed water are observed, which is not preferable.
In the present invention, the pore-containing fine particles may have a size distribution, and the coefficient of variation thereof is preferably 60% to 5%, more preferably 50% to 10%. In addition, two or more kinds of particles having different average particle sizes can be mixed and used.

<Measurement of refractive index of pore-containing fine particles>
The refractive index of the pore-containing fine particles that can be preferably used in the present invention is preferably 1.15 to 1.40, more preferably 1.15 to 1.35, and most preferably 1.18 to 1.30. . The refractive index of the particles can be determined by the following method.
(1) Preparation of matrix forming component liquid A mixed solution of 55 g of tetraethoxysilane (TEOS) (SiO ₂ concentration 28 mass%), 200 g of ethanol, 1.4 g of concentrated nitric acid and 34 g of water was stirred at room temperature for 5 hours. A liquid (M-1) containing a matrix-forming component was prepared by adjusting the amount of ethanol so that the concentration when converted to SiO ₂ was 5% by mass.
(2) Preparation of coating film The matrix-forming component liquid (M-1) and the pore-containing fine particles are converted into an oxide-converted mass ratio [matrix (SiO ₂ ): pore-containing fine particles (MO _x + SiO ₂ )]. The coating solutions for refractive index measurement were prepared so as to be 100: 0, 90:10, 80:20, 60:40, 50:50, and 25:75, respectively. Here, inorganic compounds other than silica are represented by MO _X. Each coating solution was formed on a silicon wafer whose surface was maintained at 50 ° C. by a spinner method at 300 rpm, and then heat-treated at 160 ° C. for 30 minutes, and then formed with an ellipsometer (manufactured by JASCO Corporation). The refractive index of the film for refractive index measurement was measured.
(3) Calculation of refractive index Next, the obtained refractive index and particle mixing ratio (particle: (MO _x + SiO ₂ ) / [particle: (MO _x + SiO ₂ ) + matrix: SiO ₂ ]) are plotted and extrapolated. Was used to determine the refractive index when the particles were 100%. If the percentage of pore-containing fine particles is too large, voids may occur in the coating for measurement and the refractive index of the coating may be lowered. Eliminated.

<Surface treatment method for pore-containing fine particles>
Next, a method for treating the surface of pore-containing fine particles (porous or hollow inorganic fine particles) will be described. In order to improve dispersibility in a binder for a low refractive index layer containing an alkyl fluoride portion and / or a dimethylsiloxane portion, which will be described later, the surface of the inorganic fine particles is hydrolyzed with an organosilane represented by the following general formula (I). It is preferable that the decomposition product and / or the partial condensate thereof are used for the treatment, and it is more preferable to use either an acid catalyst or a metal chelate compound or both during the treatment.

<Organosilane compound>
The organosilane compound used in the present invention will be described in detail.
Formula (I)
(R ¹⁰ ) _m -Si (X) _4-m
In the general formula (I), R ¹⁰ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a hexyl group, Examples include t-butyl group, sec-butyl group, hexyl group, decyl group, hexadecyl group and the like. Examples of the aryl group include a phenyl group and a naphthyl group, and a phenyl group is preferable.
X represents a hydroxyl group or a hydrolyzable group. As the hydrolyzable group, for example, an alkoxy group (preferably an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group and an ethoxy group), a halogen atom (for example, Cl, Br, I and the like), and R ^{2 are used.} COO groups (R ² is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples include CH ₃ COO groups and C ₂ H ₅ COO groups), preferably alkoxy groups, particularly preferably. Is a methoxy group or an ethoxy group.
m represents an integer of 1 to 3. When R ¹⁰ or X there are a plurality, a plurality of R ¹⁰ or X groups may be different, even the same, respectively. m is preferably 1 or 2, particularly preferably 1.

There are no particular limitations on the substituents contained in R ^10, a halogen atom (fluorine atom, chlorine atom, bromine atom, etc.), a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group (methyl group, Echimoto, i -Propyl group, propyl group, t-butyl group etc.), aryl group (phenyl group, naphthyl group etc.), aromatic heterocyclic group (furyl group, pyrazolyl group, pyridyl group etc.), alkoxy group (methoxy group, ethoxy group) , I-propoxy group, hexyloxy group etc.), aryloxy group (phenoxy group etc.), alkylthio group (methylthio group, ethylthio group etc.), arylthio group (phenylthio group etc.), alkenyl group (vinyl group, 1-propenyl group) Etc.), acyloxy group (acetoxy group, acryloyloxy group, methacryloyloxy group, etc.), alkoxycarbonyl group (meth) Xycarbonyl group, ethoxycarbonyl group, etc.), aryloxycarbonyl group (phenoxycarbonyl group, etc.), carbamoyl group (carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N-methyl-N-octylcarbamoyl group) Etc.), acylamino groups (acetylamino group, benzoylamino group, acrylamino group, methacrylamino group, etc.) and the like, and these substituents may be further substituted. In the present specification, even if a hydrogen atom is replaced by a single atom, it is treated as a substituent for convenience.
When there are a plurality of R ¹⁰ , at least one is preferably a substituted alkyl group or a substituted aryl group. Among these, the substituted alkyl group or substituted aryl group preferably further has a vinyl polymerizable group. In this case, the compound represented by the general formula (I) is a vinyl polymerizable compound represented by the following general formula (II). It can be expressed as an organosilane compound having a substituent.

Formula (II)

In the general formula (II), R ¹ represents a hydrogen atom, a methyl group, a methoxy group, an alkoxycarbonyl group, a cyano group, a fluorine atom or a chlorine atom. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group. R ¹ is preferably a hydrogen atom, a methyl group, a methoxy group, a methoxycarbonyl group, a cyano group, a fluorine atom or a chlorine atom, more preferably a hydrogen atom, a methyl group, a methoxycarbonyl group, a fluorine atom or a chlorine atom, And methyl groups are particularly preferred.
Y represents a single bond, an ester group, an amide group, an ether group or a urea group. Single bonds, ester groups and amide groups are preferred, single bonds and ester groups are more preferred, and ester groups are particularly preferred.

  L is a divalent linking chain, specifically, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, and a linking group (for example, an ether group, an ester group, an amide group) inside. A substituted or unsubstituted alkylene group, or a substituted or unsubstituted arylene group having a linking group therein, among which a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted carbon number 6 An alkylene group having 2 to 20 arylene groups and an alkylene group having 2 to 10 carbon atoms having a linking group therein is preferable, and an alkylene group having an unsubstituted alkylene group, an unsubstituted arylene group, and an ether linking group or an ester linking group inside is further included. An unsubstituted alkylene group and an alkylene group having an ether linking group or an ester linking group therein are particularly preferred. Examples of the substituent include a halogen, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, and an aryl group, and these substituents may be further substituted.

n represents 0 or 1. When there are a plurality of Xs, the plurality of Xs may be the same or different. n is preferably 0.
R ¹⁰ has the same meaning as R ^{10 in} formula (I), preferably a substituted or unsubstituted alkyl group or an unsubstituted aryl group, and more preferably an unsubstituted alkyl group or an unsubstituted aryl group.
X has the same meaning as X in formula (I), preferably a halogen, a hydroxyl group or an unsubstituted alkoxy group, more preferably a chlorine, a hydroxyl group or an unsubstituted alkoxy group having 1 to 6 carbon atoms, a hydroxyl group or a carbon number. 1-3 alkoxy groups are more preferable, and a methoxy group is particularly preferable.

As the organosilane compound used in the present invention, those represented by the following general formula (III) are also preferred.
Formula _{(III) (Rf-L 1} ) n -Si (X 1) 4-n
In the above formula, Rf represents a linear, branched or cyclic fluorinated alkyl group having 1 to 20 carbon atoms or a fluorinated aromatic group having 6 to 14 carbon atoms. Rf is preferably a linear, branched or cyclic fluoroalkyl group having 3 to 10 carbon atoms, and more preferably a linear fluoroalkyl group having 4 to 8 carbon atoms. L ₁ represents a divalent linking group having 10 or less carbon atoms, preferably an alkylene group having 1 to 10 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms. The alkylene group is a linear or branched, substituted or unsubstituted alkylene group which may have a linking group (for example, ether, ester, amide) inside. The alkylene group may have a substituent, and preferable substituents in that case include a halogen atom, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, and an aryl group. X ₁ has the same meaning as X in formula (I), preferably a halogen, a hydroxyl group or an unsubstituted alkoxy group, more preferably a chlorine, a hydroxyl group or an unsubstituted alkoxy group having 1 to 6 carbon atoms, a hydroxyl group or a carbon number. 1-3 alkoxy groups are more preferable, and a methoxy group is particularly preferable.
n represents an integer of 1 to 3, preferably 1 or 2, and more preferably 1.

Next, among the organosilane compounds (fluorinated silane coupling agents) represented by the general formula (III), the fluorine-containing silane coupling agents represented by the following general formula (IV) are preferable.
Formula _{(IV) C n F 2n +} 1 - (CH 2) m -Si (X 2) 3
In the above formula, n represents an integer of 1 to 10, and m represents an integer of 1 to 5. n is preferably 4 to 10, m is preferably 1 to 3, and X ₂ represents a methoxy group, an ethoxy group, and a chlorine atom.

  Two or more compounds represented by general formula (I) to general formula (IV) may be used in combination. Specific examples of the compounds represented by general formula (I) to general formula (IV) are shown below, but the present invention is not limited thereto.

Among these specific examples, (M-1), (M-2), (M-30), (M-35), (M-49), (M-51), (M-56), (M-57) and the like are particularly preferable. Further, the compounds of A, B and C described in [Reference Example] of Japanese Patent No. 3474330 are also excellent in dispersion stability and preferable. In the present invention, the amount of the organosilane compound represented by the general formula (I) to the general formula (IV) is not particularly limited, but is preferably 1% by mass to 300% by mass, more preferably, per inorganic fine particle. It is 3 mass%-100 mass%, Most preferably, it is 5 mass%-50 mass%. The molar concentration based on the hydroxyl group on the surface of the inorganic oxide is preferably 1 to 300 mol%, more preferably 5 to 300 mol%, and most preferably 10 to 200 mol%.
When the amount of the organosilane compound used is in the above range, a sufficient stabilizing effect of the dispersion can be obtained, and the film strength is also increased during coating film formation. It is also preferable to use a plurality of types of organosilane compounds in combination, and a plurality of types of compounds can be added at the same time, or the reaction can be carried out by shifting the addition time. Also, it is preferable to add a plurality of kinds of compounds in the form of partial condensates in advance because the reaction control is easy.

In the present invention, the dispersibility of the inorganic fine particles can be improved by allowing the organosilane to hydrolyze and / or its partial condensate to act on the surface of the inorganic fine particles.
In the hydrolysis condensation reaction, 0.3 to 2.0 mol, preferably 0.5 to 1.0 mol of water is added to 1 mol of the hydrolyzable group (X, X ₁ , X ₂ ). It is preferably carried out by stirring at 15 to 100 ° C. in the presence of the acid catalyst or metal chelate compound used in the invention.

<Catalyst for improving dispersibility>
The treatment for improving the dispersibility by the hydrolyzate of organosilane and / or the condensation reaction product is preferably performed in the presence of a catalyst. Catalysts include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid; organic acids such as oxalic acid, acetic acid, formic acid, methanesulfonic acid and toluenesulfonic acid; inorganic bases such as sodium hydroxide, potassium hydroxide and ammonia; triethylamine, Examples include organic bases such as pyridine; metal alkoxides such as triisopropoxyaluminum and tetrabutoxyzirconium. From the viewpoint of production stability and storage stability of the inorganic oxide fine particle liquid, an acid catalyst is used in the present invention. It is preferable to use (inorganic acids, organic acids) and / or metal chelate compounds. Among inorganic acids, hydrochloric acid, sulfuric acid, and organic acids preferably have an acid dissociation constant in water (pKa value (25 ° C.)) of 4.5 or less, and an acid dissociation constant in hydrochloric acid, sulfuric acid, or water of 3.0 or less. More preferred is an organic acid having an acid dissociation constant of 2.5 or less in hydrochloric acid, sulfuric acid or water, more preferred is an organic acid having an acid dissociation constant of 2.5 or less in water, and methanesulfonic acid. Further, oxalic acid, phthalic acid, and malonic acid are more preferable, and oxalic acid is particularly preferable.

  When the hydrolyzable group of the organosilane is an alkoxy group and the acid catalyst is an organic acid, the amount of water added can be reduced because the carboxyl group or sulfo group of the organic acid supplies protons. The amount of water added to 1 mol of the alkoxide group of the organosilane is 0 to 2 mol, preferably 0 to 1.5 mol, more preferably 0 to 1 mol, and particularly preferably 0 to 0.5 mol. Further, when alcohol is used as a solvent, it is also preferable that water is not substantially added.

In the present invention, the metal chelate compound used for improving the dispersibility by the hydrolyzate and / or condensation reaction product of organosilane has a general formula R ³ OH (wherein R ³ represents an alkyl group having 1 to 10 carbon atoms). And an alcohol represented by the general formula R ⁴ COCH ₂ COR ⁵ (wherein R ⁴ is an alkyl group having 1 to 10 carbon atoms, R ⁵ is an alkyl group having 1 to 10 carbon atoms or 1 to 1 carbon atoms). And at least one metal chelate compound having a metal selected from Zr, Ti, and Al as a central metal, wherein the compound represented by 10) is a ligand.
The metal chelate compound can be suitably used without particular limitation as long as it has a metal selected from Zr, Ti, or Al as a central metal. Within this category, two or more metal chelate compounds may be used in combination. Specific examples of the metal chelate compound used in the present invention include tri-n-butoxyethyl acetoacetate zirconium, di-n-butoxybis (ethylacetoacetate) zirconium, n-butoxytris (ethylacetoacetate) zirconium, tetrakis (n Zirconium chelate compounds such as propylacetoacetate) zirconium, tetrakis (acetylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium; diisopropoxy bis (ethylacetoacetate) titanium, diisopropoxy bis (acetylacetate) titanium , Titanium chelate compounds such as diisopropoxy bis (acetylacetone) titanium; diisopropoxyethyl acetoacetate aluminum Diisopropoxyacetylacetonate aluminum, isopropoxybis (ethylacetoacetate) aluminum, isopropoxybis (acetylacetonate) aluminum, tris (ethylacetoacetate) aluminum, tris (acetylacetonato) aluminum, monoacetylacetonate bis Examples thereof include aluminum chelate compounds such as (ethyl acetoacetate) aluminum.
Among these metal chelate compounds, tri-n-butoxyethyl acetoacetate zirconium, diisopropoxybis (acetylacetonate) titanium, diisopropoxyethyl acetoacetate aluminum, and tris (ethyl acetoacetate) aluminum are preferable. These metal chelate compounds can be used individually by 1 type or in mixture of 2 or more types. Moreover, the partial hydrolyzate of these metal chelate compounds can also be used.

<Dispersant>
In the present invention, a dispersant may be used to prepare inorganic fine particles by dispersing them from a powder in a solvent. In the present invention, it is preferable to use a dispersant having an anionic group.
As the anionic group, a group having an acidic proton such as a carboxyl group, a sulfonic acid group (sulfo), a phosphoric acid group (phosphono), a sulfonamide group, or a salt thereof is effective, and in particular, a carboxyl group, a sulfonic acid group, A phosphoric acid group or a salt thereof is preferable, and a carboxyl group and a phosphoric acid group are particularly preferable. A plurality of anionic groups may be contained for the purpose of further improving the dispersibility. The average number is preferably 2 or more, more preferably 5 or more, and particularly preferably 10 or more. Moreover, the anionic group contained in a dispersing agent may contain multiple types in 1 molecule.
The dispersant may further contain a crosslinking or polymerizable functional group. Crosslinkable or polymerizable functional groups include ethylenically unsaturated groups (for example, (meth) acryloyl groups, allyl groups, styryl groups, vinyloxy groups, etc.) that can undergo addition reactions and polymerization reactions with radical species, and cationic polymerizable groups (epoxy Groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups) and the like, and functional groups having an ethylenically unsaturated group are preferred.

<Low refractive index layer material>
Hereinafter, other materials preferably used for the low refractive index layer of the present invention will be described. The low refractive index layer of the antireflection film of the present invention is preferably formed by applying, drying and curing the curable composition containing the pore-containing fine particles.
In the present invention, from the viewpoint of lowering the refractive index of the low refractive index layer and lowering the refractive index of the antireflection film, the curable composition preferably contains a component having an alkyl fluoride moiety. As the component having an alkyl fluoride part, the following polymer having an alkyl fluoride part is preferably used.
Fluorinated vinyl monomers for introducing an alkyl fluoride moiety include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, etc.), (meth) acrylic acid moieties or fully fluorinated alkyl esters Derivatives (for example, Biscoat 6FM (trade name, manufactured by Osaka Organic Chemical Co., Ltd.), R-2020 (trade name, manufactured by Daikin) and the like, and fully or partially fluorinated vinyl ethers, etc. may be mentioned, but perfluoroolefins are preferred. From the viewpoints of refractive index, solubility, transparency, availability, etc., hexafluoropropylene is particularly preferred. Increasing the composition ratio of these fluorine-containing vinyl monomers can lower the refractive index but lowers the film strength. In the present invention, it is preferable to introduce the fluorine-containing vinyl monomer so that the fluorine content of the copolymer is 20 to 60% by mass, more preferably 25 to 55% by mass, and particularly preferably 30 to 50% by mass. This is a case of mass%.

  The polymer having an alkyl fluoride portion preferably has a repeating unit having a (meth) acryloyl group in the side chain as an essential constituent component. If the composition ratio of these (meth) acryloyl group-containing repeating units is increased, the film strength is improved, but the refractive index is also increased. Generally, the (meth) acryloyl group-containing repeating unit preferably occupies 5 to 90% by mass and preferably 30 to 70% by mass, although it varies depending on the type of repeating unit derived from the fluorine-containing vinyl monomer. Is more preferable, and it is particularly preferable to occupy 40 to 60% by mass.

  In addition to the repeating units derived from the above-mentioned fluorine-containing vinyl monomers and the repeating units having a (meth) acryloyl group in the side chain, the polymer having an alkyl fluoride moiety contributes to adhesion to the substrate and Tg of the polymer (film hardness) And other vinyl monomers can be copolymerized as appropriate from various viewpoints such as solubility in a solvent, transparency, slipperiness, dust resistance and antifouling properties. A plurality of these vinyl monomers may be combined depending on the purpose, and are preferably introduced in the range of 0 to 65 mol% in the copolymer in total, and in the range of 0 to 40 mol%. More preferably, it is particularly preferably in the range of 0 to 30 mol%.

  The vinyl monomer unit that can be used in combination is not particularly limited. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid) 2-ethylhexyl, 2-hydroxyethyl acrylate), methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate, etc.), styrene derivatives (styrene, p-hydroxymethylstyrene, p -Methoxystyrene, etc.), vinyl ethers (methyl vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, etc.), vinyl esters (vinyl acetate) Vinyl propionate, vinyl cinnamate, etc.), unsaturated carboxylic acids (acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, etc.), acrylamides (N, N-dimethylacrylamide, N-tert-butylacrylamide, N -Cyclohexyl acrylamide, etc.), methacrylamides (N, N-dimethylmethacrylamide), acrylonitrile and the like.

From the viewpoint of lowering the refractive index of the low refractive index layer and excellent scratch resistance, the polymer having an alkyl fluoride moiety used in the present invention is represented by General Formula 1 and General Formula 2 of JP-A-2004-45462. The polymer is particularly preferable, and specific examples and synthesis methods thereof are described in [0043] to [0053] and [0079] to [0082] of the publication.
The alkyl fluoride part is preferably 1 to 60% by mass, and more preferably 3 to 50% by mass, based on the total solid content of the low refractive index layer.

  As a material for constituting the low refractive index layer, a curable composition containing the pore-containing fine particles and a film-forming binder described later (for example, a monomer having two or more ethylenically unsaturated groups) is also preferable. When the curable composition for constituting the low refractive index layer is an ionizing radiation curable type, the curable composition is a photo radical polymerization initiator or a thermal radical polymerization initiator described later in the section of the film forming binder. It is preferable to contain.

Instead of or in addition to a polymer having an alkyl fluoride moiety or a monomer having two or more ethylenically unsaturated groups, a monomer having a crosslinkable functional group is used to introduce a crosslinkable functional group into the polymer. The crosslinked structure may be introduced into the binder polymer by the reaction of the crosslinkable functional group.
Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. That is, in the present invention, the crosslinkable functional group may not react immediately but may exhibit reactivity as a result of decomposition.
These binder polymers having a crosslinkable functional group can form a crosslinked structure by heating after coating.
The monomer having the crosslinkable functional group may react with the polymer main body before the application of the antireflection film to form a crosslinkable polymer, but may be crosslinked with the polymer main body only after application to form a matrix. it can.

  In the present invention, a hydrolyzate of organosilane and / or a partial condensate thereof is added to the curable composition from the viewpoint that the film strength can be improved in combination with the ionizing radiation or thermosetting binder described above. It is preferable. For the synthesis of the partial condensate (abbreviated as sol) of the organosilane compound, the organosilane compound used in the treatment for improving the dispersibility of the inorganic oxide fine particles of the present invention and the acid and / or metal chelate compound as a catalyst are used. be able to.

In the present invention, the binder that can be preferably used in addition to the above-mentioned light or thermosetting binder is a hydrolyzate of the organosilane compound represented by the general formulas (I) to (IV) and / or its The partial condensate itself can be mentioned. When the organosilane compound has an alkyl fluoride part, it is preferable from the viewpoint of a decrease in refractive index. Examples of preferred binders are described in, for example, JP-A Nos. 2002-202406, 2002-265866, and 317152.
The amount of organosilane sol used for the polymer having an alkyl fluoride moiety in the low refractive index layer is 5 from the viewpoints of the effect of using the sol, the refractive index of the layer, and the shape and surface shape of the layer to be formed. -100 mass% is preferable, 5-40 mass% is more preferable, 8-35 mass% is still more preferable, 10-30 mass% is especially preferable.

  In the present invention, it is preferable that a β-diketone compound and / or a β-ketoester compound is further added to the curable composition for forming a low refractive index layer. Specific examples of the β-diketone compound and / or β-ketoester compound include acetylacetone, methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, acetoacetate-i-propyl, acetoacetate-n-butyl, acetoacetate. Acetic acid-sec-butyl, acetoacetic acid-t-butyl, 2,4-hexane-dione, 2,4-heptane-dione, 3,5-heptane-dione, 2,4-octane-dione, 2,4-nonane -Dione, 5-methyl-hexane-dione and the like can be mentioned. Of these, ethyl acetoacetate and acetylacetone are preferred, and acetylacetone is particularly preferred. These β-diketone compounds and / or β-ketoester compounds may be used alone or in combination of two or more. In the present invention, the β-diketone compound and / or β-ketoester compound is preferably used in an amount of 2 mol or more, more preferably 3 to 20 mol, per 1 mol of the metal chelate compound. If it is less than 2 mol, the storage stability of the resulting composition may be inferior, which is not preferable.

<Addition of low surface free energy component>
In the present invention, it is preferable to reduce the surface free energy on the surface of the antireflection film from the viewpoint of improving the antifouling property. Specifically, it is preferable to use a fluorine-containing compound or a compound having a dialkylsiloxane part in the low refractive index layer. Examples of the additive having a polysiloxane structure having a dialkylsiloxane portion include reactive group-containing polysiloxanes (for example, X-22-174DX, X-22-2426, X-22-164B, X22 manufactured by Shin-Etsu Chemical Co., Ltd.). -164C, X-22-170DX, X-22-176D, X-22-1821 (named above) and Chisso Corporation, FM-0725, FM-7725, FM-4421, FM-5521, FM6621, FM-1121, Gelest DMS-U22, RMS-033, RMS-083, UMS-182, DMS-H21, DMS-H31, HMS-301, FMS121, FMS123, FMS131, FMS141, FMS221 (and above) It is also preferable to add. Further, silicone compounds described in Tables 2 and 3 of JP-A-2003-112383 can also be preferably used. These polysiloxanes are preferably added in the range of 0.1 to 10% by mass of the total solid content of the low refractive index layer, particularly preferably 1 to 5% by mass.
It is also preferable to provide an antifouling layer of a silane coupling agent containing a perfluoroether group as described in JP-A No. 2002-277604.

<Physical properties of low refractive index layer>
The refractive index of the low refractive index layer in the present invention is preferably 1.46 or less, more preferably 1.20 to 1.46, still more preferably 1.25 to 1.40, and particularly preferably. Is particularly preferably 1.25 to 1.38.
The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 120 nm. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less. The specific strength of the low refractive index layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test under a 500 g load.
Moreover, in order to improve the antifouling performance of the antireflection film, it is preferable that the contact angle of water on the surface is 90 ° or more. More preferably, it is 95 ° or more, and particularly preferably 100 ° or more.

[Layer structure of antireflection film]
The antireflection film of the present invention has a low moisture-permeable cured layer on a transparent substrate film (hereinafter also referred to as “substrate”), and has a refractive index so that the reflectance is reduced by optical interference, The antireflection layer is laminated in consideration of the film thickness, the number of layers, the layer order, and the like. Moreover, you may have a hard-coat layer as needed, and you may provide a hard-coat function to a low moisture-permeable cured layer. The antireflective film of the present invention has a low refractive index layer in the antireflective layer, and in the simplest structure, only a low moisture permeable cured layer and a low refractive index layer are coated in this order on the transparent substrate film. is there. The outermost surface of the antireflection film is preferably a low refractive index layer. In order to further reduce the reflectance, the antireflection layer is preferably composed of a combination of a high refractive index layer having a higher refractive index than the substrate and a low refractive index layer having a lower refractive index than the substrate. Examples of the configuration of the antireflection layer include two layers of a high refractive index layer / low refractive index layer from the base material side, and three layers having different refractive indices, a medium refractive index layer (base material, low moisture permeability cured layer). Or a layer having a refractive index higher than that of the hard coat layer and lower than that of the high refractive index layer) / high refractive index layer / low refractive index layer. A laminate of these has also been proposed. Especially, it is preferable to apply | coat in order of a middle refractive index layer / high refractive index layer / low refractive index layer on the base material which has a low moisture-permeable cured layer from durability, an optical characteristic, cost, productivity, etc.

The example of the preferable layer structure of the antireflection film of this invention is shown below. In the following configuration, the transparent substrate film functions as a support.
-Transparent substrate film / low moisture permeability cured layer / antiglare layer / low refractive index layer,
Transparent substrate film / low moisture permeability cured layer / antiglare layer / antistatic layer / low refractive index layer Transparent substrate film / low moisture permeability cured layer / antistatic layer / antiglare layer / low refractive index layer Transparent Base film / low moisture permeability cured layer / high refractive index layer / low refractive index layer,
Transparent substrate film / low moisture permeability cured layer / antistatic layer / high refractive index layer / low refractive index layerTransparent substrate film / low moisture permeability cured layer / medium refractive index layer / high refractive index layer / low refractive index Layer Transparent substrate film / low moisture permeability cured layer / antiglare layer / high refractive index layer / low refractive index layer,
-Transparent base film / Low moisture permeability cured layer / Anti-glare layer / Medium refractive index layer / High refractive index layer / Low refractive index layer,
-Transparent base film / Antistatic layer / Low moisture permeability cured layer / Medium refractive index layer / High refractive index layer / Low refractive index layer,
Antistatic layer / transparent substrate film / low moisture permeability cured layer / medium refractive index layer / high refractive index layer / low refractive index layer,
・ Base film / low moisture permeability cured layer / antistatic layer / antiglare layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Antistatic layer / transparent substrate film / low moisture permeability cured layer / antiglare layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Antistatic layer / transparent substrate film / low moisture permeability cured layer / antiglare layer / high refractive index layer / low refractive index layer / high refractive index layer / low refractive index layer.
When the low moisture-permeable cured layer does not have a hard coat function, a hard coat layer may be laminated on the low moisture-permeable cured layer as necessary.
As long as the reflectance can be reduced by optical interference, it is not limited to these layer configurations. The high refractive index layer may be a light diffusing layer having no antiglare property. It is also possible to design the low moisture-permeable cured layer or hard coat layer as a high refractive index medium refractive index layer and reduce the number of layers.
The antistatic layer is preferably a layer containing conductive polymer particles or metal oxide fine particles (for example, ATO, ITO), and can be provided by coating or atmospheric pressure plasma treatment.

[Film-forming binder]
In the present invention, as the main film-forming binder component of the film-forming composition for forming each layer such as a high (medium) refractive index layer, it is possible to use a compound having an ethylenically unsaturated group as the film strength, It is preferable in terms of stability, coating film productivity, and the like. The main film-forming binder refers to one that accounts for 10% by mass or more of the film-forming components excluding inorganic fine particles. Preferably, they are 20 mass% or more and 100 mass% or less, More preferably, they are 30 mass% or more and 95% or less.
A polymer having a saturated hydrocarbon chain or a polyether chain as a main chain is preferable, and a polymer having a saturated hydrocarbon chain as a main chain is more preferable. As the binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure, a (co) polymer of monomers having two or more ethylenically unsaturated groups is preferable.
In order to obtain a high refractive index layer, it is preferable that the monomer structure contains at least one kind of atom selected from an aromatic ring, a halogen atom other than fluorine, a sulfur atom, a phosphorus atom, and a nitrogen atom.

  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-cyclohexanediacrylate, pentaerythritol tetra ( (Meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, di Pentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polymer Acrylate), vinylbenzene and its derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (eg, divinylsulfone), acrylamide (eg, , Methylenebisacrylamide) and methacrylamide. Two or more of these monomers may be used in combination.

  Specific examples of the high refractive index monomer include bis (4-methacryloylthiophenyl) sulfide, vinyl naphthalene, vinyl phenyl sulfide, 4-methacryloxyphenyl-4′-methoxyphenyl thioether, and the like. Two or more of these monomers may be used in combination.

  Polymerization of the monomer having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator.

Photo radical polymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds , Fluoroamine compounds and aromatic sulfoniums. Examples of acetophenones include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone and 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone is included. Examples of benzoins include benzoin benzene sulfonate, benzoin toluene sulfonate, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether. Examples of the benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone. Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
Various examples are also described in the latest UV curing technology (P.159, issuer: Kazuhiro Takasagi, publisher; Technical Information Association, Inc., published in 1991), which is useful for the present invention.
Preferable examples of commercially available photocleavable photoradical polymerization initiators include Irgacure (651, 184, 907) manufactured by Nippon Ciba-Geigy Co., Ltd.
It is preferable to use a photoinitiator in the range of 0.1-15 mass parts with respect to 100 mass parts of polyfunctional monomers, More preferably, it is the range of 1-10 mass parts.
In addition to the photopolymerization initiator, a photosensitizer may be used. Specific examples of the photosensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, Michler's ketone and thioxanthone.

As the thermal radical initiator, organic or inorganic peroxides, organic azo, diazo compounds, and the like can be used.
Specifically, benzoyl peroxide, halogen benzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide, butyl hydroperoxide as organic peroxides, hydrogen peroxide, peroxides as inorganic peroxides. 2,2′-azobis (isobutyronitrile), 2,2′-azobis (propionitrile), 1,1′-azobis (cyclohexanecarbonitrile), etc. as diazo compounds such as ammonium sulfate and potassium persulfate Examples of the compound include diazoaminobenzene and p-nitrobenzenediazonium.

In the present invention, a polymer having a polyether as a main chain can also be used.
A ring-opening polymer of a polyfunctional epoxy compound is preferred. The ring-opening polymerization of the polyfunctional epoxy compound can be performed by irradiation with ionizing radiation or heating in the presence of a photoacid generator or a thermal acid generator.

Instead of or in addition to a monomer having two or more ethylenically unsaturated groups, a monomer having a crosslinkable functional group is used to introduce a crosslinkable functional group into the polymer, and by reaction of this crosslinkable functional group, A crosslinked structure may be introduced into the binder polymer.
Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. That is, in the present invention, the crosslinkable functional group may not react immediately but may exhibit reactivity as a result of decomposition.
These binder polymers having a crosslinkable functional group can form a crosslinked structure by heating after coating.

[Material for high refractive index layer]
In the present invention, it is preferable to provide a high refractive index layer. The high refractive index layer is formed from the above-mentioned film forming binder, matte particles for imparting antiglare properties or internal scattering properties, and inorganic fillers for increasing the refractive index, preventing crosslinking shrinkage, and increasing the strength. be able to.

For the purpose of imparting antiglare properties, the high refractive index layer has matte particles larger than filler particles and an average particle size of 0.1 to 5.0 μm, preferably 1.5 to 3.5 μm, such as inorganic compound particles. Alternatively, resin particles can be contained. If the refractive index difference between the matte particles and the binder is too large, the film becomes cloudy, and if it is too small, a sufficient light diffusing effect cannot be obtained, so 0.02 to 0.20 is preferable, and 0.04 to Particularly preferred is 0.10. If the addition amount of the mat particles to the binder is too large, the film becomes cloudy if it is too large, and if it is too small, a sufficient light diffusion effect cannot be obtained. A percentage is particularly preferred.
As specific examples of the mat particles, inorganic particles such as silica particles and TiO ₂ particles; resin particles such as acrylic particles, cross-linked acrylic particles, polystyrene particles, cross-linked styrene particles, melamine resin particles, and benzoguanamine resin particles are preferable. Can be mentioned. Of these, crosslinked styrene particles, crosslinked acrylic particles, and silica particles are preferred.
The shape of the mat particles can be either a true sphere or an indefinite shape.

  Two or more different kinds of mat particles may be used in combination. When two or more kinds of mat particles are used, the difference in refractive index is preferably 0.02 or more and 0.10 or less in order to effectively exert the refractive index control by mixing the two, and 0.03 or more. Is particularly preferably 0.07 or less. Further, it is possible to impart an antiglare property with mat particles having a larger particle size and to impart another optical characteristic with mat particles having a smaller particle size. For example, when an optical film is attached to a high-definition display of 133 ppi or more, it is required that there is no problem in optical performance called glare. Glare originates from the fact that the pixels are enlarged or reduced due to unevenness existing on the film surface (contributing to anti-glare properties) and lose uniformity of brightness, but with a particle size smaller than that of mat particles that provide anti-glare properties. It can be greatly improved by using mat particles having a different refractive index from the binder.

  Furthermore, the particle size distribution of the mat particles is most preferably monodisperse, and the particle sizes of the particles are preferably closer to each other. For example, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the proportion of the coarse particle is preferably 1% or less, more preferably 0.1% of the total number of particles. Or less, more preferably 0.01% or less. Matt particles having such a particle size distribution are obtained by classification after a normal synthesis reaction, and a matting agent having a more preferable distribution can be obtained by increasing the number of classifications or increasing the degree of classification.

The mat particles are contained so that the amount of mat particles in the formed high refractive index layer is preferably 10 to 1000 mg / m ² , more preferably 100 to 700 mg / m ² .
The particle size distribution of the mat particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution.

The high refractive index layer includes an oxide of at least one metal selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony in order to increase the refractive index of the layer and to reduce cure shrinkage. It is preferable that an inorganic filler having an average particle size of 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less is contained.
In order to increase the difference in refractive index from the mat particles, in order to keep the refractive index of the high refractive index layer using the high refractive index mat particles low, a silicon oxide may be used as a filler. preferable. The preferred particle size is the same as that of the aforementioned inorganic filler. For this purpose, the aforementioned pore-containing fine particles preferably used in the present invention can also be used.
Specific examples of the inorganic filler used for the high refractive index layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and SiO ₂ . TiO ₂ and ZrO ₂ are particularly preferable from the viewpoint of increasing the refractive index. The surface of the inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.
The amount of these inorganic fillers added is preferably 10 to 90% of the total mass of the high refractive index layer, more preferably 20 to 80%, and particularly preferably 30 to 70%.
In addition, since such a filler has a particle size sufficiently smaller than the wavelength of light, scattering does not occur, and a dispersion in which the filler is dispersed in a binder polymer behaves as an optically uniform substance.

  The bulk refractive index of the mixture of the binder and inorganic filler of the high refractive index layer of the present invention is preferably 1.48 to 2.00, more preferably 1.50 to 1.80. In order to make the refractive index within the above range, the kind and amount ratio of the binder and the inorganic filler may be appropriately selected. How to select can be easily known experimentally in advance.

  The antireflective film of the present invention is preferably provided with a medium refractive index layer having a refractive index lower than that of the high refractive index layer and higher than that of the support, and the medium refractive index layer is used as a high refractive index layer. It can be formed in the same manner as the high refractive index layer by adjusting the amount of the refractive index filler or the high refractive index monomer used.

[Hard coat layer]
The hard coat layer may be provided on the low moisture-permeable cured layer in order to impart physical strength to the antireflection film.

  The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of a light and / or heat curable compound. The curable functional group is preferably a photopolymerizable functional group, and the hydrolyzable functional group-containing organometallic compound is preferably an organic alkoxysilyl compound. Specific examples of the composition of the hard coat layer include those described in JP-A Nos. 2002-144913, 2000-9908, and WO 00/46617.

  The film thickness of the hard coat layer can be appropriately designed depending on the application. The film thickness of the hard coat layer is preferably 0.2 to 10 μm, more preferably 0.5 to 7 μm.

  The hardness of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K-5400 (however, load 4.9 N).

[Transparent substrate film]
The transparent substrate film used in the present invention is preferably a transparent film-like sheet or plate-like plastic. Specific examples include polyesters such as polyethylene terephthalate and polyethylene naphthalate, cellulose acylate films, polycarbonate, polymethyl methacrylate, polysulfone, polyethersulfone, polyarylate, and cycloolefin polymers. A cellulose acylate film is preferably used because it is optically uniform, has a smooth surface, and has good secondary workability in producing a polarizing plate. The cellulose acylate film is preferably a film made of cellulose acylates, more preferably a film made of cellulose acetate, cellulose acetate propionate, or cellulose acetate butyrate. 20-300 micrometers is preferable and, as for the thickness of a transparent base film, 40-200 micrometers is more preferable. When the thickness of the base film is too thin, the film strength is weak, and when it is thick, the rigidity becomes too large.

The antireflection film of the present invention thus formed has a haze value of 3 to 70%, preferably 4 to 60%, and an average reflectance of 450 nm to 650 nm of 3.0% or less, preferably Is 2.5% or less.
When the antireflection film of the present invention has a haze value and an average reflectance in the above range, good antiglare property or internal scattering property and antireflection property can be obtained without causing deterioration of the transmitted image.

  In the antireflection film of the present invention, a low moisture-permeable cured layer is formed on a transparent substrate film, and the thickness thereof is 1 to 10 μm, preferably 1 to 5 μm. When a low moisture-permeable cured layer is provided on the transparent substrate film, the moisture permeability decreases when the thickness is increased, but the curl increases, and the subsequent step of producing a polarizing plate, for example, an adhesion process with a polarizer, This causes trouble in handling. Further, not only the manufacturing process but also the curling of the polarizing plate is not preferable because it causes display unevenness in the LCD. Therefore, the upper limit of the film thickness of the low moisture-permeable cured layer is preferably in the above range in order to reduce the curl to such an extent that it does not occur or is practically unproblematic. On the other hand, the lower limit of the film thickness is defined by a range more preferable than physical properties such as moisture permeability and pencil hardness, and is preferably 1 μm or more. The low moisture-permeable cured layer is composed of at least one layer, and two or more layers are also possible.

Since the antireflection film of the present invention has a low moisture permeability cured layer, the moisture permeability at JIS-Z-0208 (60 ° C./95% relative humidity) is 1000 g / m ² · day or less. A commercially available cellulose acetate film has a thickness of 80 μm and a moisture permeability of 1400 to 1500 g / m ² · day under the above conditions. When a polarizing plate is produced when the moisture permeability is high, there is a problem that water vapor enters the polarizer through the cellulose acetate protective layer under a high temperature and high humidity environment, and the degree of polarization decreases. As a result of intensive studies, the present inventors have achieved performance as a polarizing plate by setting the moisture permeability to 1000 g / m ² · day or less, preferably 800 g / m ² · day or less, more preferably 700 g / m ² · day or less. It was found that (polarization degree, single plate transmittance) is practically useful without deterioration.

  The pencil hardness of the antireflection film of the present invention is preferably H or higher, more preferably 2H or higher. The pencil hardness can be controlled by adjusting the thickness and composition of the low moisture permeability cured layer and the hard coat layer. In addition, the surface elastic modulus of the low moisture permeability cured layer and the hard coat layer in the present invention is preferably 4.0 GPa or more and 10 GPa or less, more preferably 4.5 GPa or more and 9 or less, in order to obtain sufficient pencil hardness and scratch resistance. 0.0 GPa or less. Also, it is widely practiced to increase the surface elastic modulus by adding inorganic fine particles, but the brittleness deteriorates as inorganic fine particles are added. When the surface elastic modulus is in the above range, preferable results are obtained in pencil hardness, scratch resistance and brittleness. The surface elastic modulus of the low moisture-permeable cured layer and the hard coat layer can be controlled by adjusting the composition of the curable composition.

  An inorganic layered compound can also be added to the low moisture-permeable cured layer used in the antireflection film of the present invention. For curing the layered compound, synthetic mica and synthetic smectite are preferably used. Specific examples of synthetic mica include Micromica, MK-100, MK-200, MK-300, Somasif ME-100, MAE, MTE, MEE, MPE, manufactured by Corp Chemical Co., Ltd. , SWN, SAN, STN, SEN, SPN. Synthetic smectites STN and SPN are preferred from the transparency of the cured product and dispersibility in the curable composition.

In the antireflection film of the present invention, the value when curl is represented by the following formula B is preferably in the range of minus 15 to plus 15, more preferably in the range of minus 12 to plus 12. Is minus 10 to plus 10. In this case, the measurement direction of the curl in the sample is measured in the conveyance direction of the base material in the case of application in a web form.
Formula B: Curl = 1 / R R is the radius of curvature (m)
Curl is an important characteristic for preventing cracks and film peeling in the production, processing, and market handling of a film having a cured layer such as a low moisture permeability cured layer or a hard coat layer according to the present invention. It is preferable that the curl value is in the above range and the curl is small. The curl can be reduced within the above range and the high surface hardness can be achieved by setting the volume shrinkage ratio before and after curing of the curable composition for forming a cured layer to 15% or less. The curl is measured by using the curl measurement template of Method A in “Measurement Method of Curling of Photographic Film” of JIS K7619-1988. The measurement conditions are 25 ° C., relative humidity 60%, and humidity control time 10 hours. Here, “curl plus” means a curl in which the cured layer coating side of the film is inside the curve, and “minus” means a curl in which the coating side is outside the curve.

  In the antireflection film of the present invention, when only the relative humidity is changed from 80% to 10% based on the curl measurement method, the absolute value of the difference between the curl values is preferably 24 to 0, and 15 to 0. Is more preferable, and 8 to 0 is most preferable. This is a property related to handling, peeling, and cracking when films are attached under various humidity.

  The anti-cracking property of the antireflection film of the present invention is preferably such that the radius of curvature at which cracking occurs when rolled with the cured layer coating side of the support facing outward is preferably 30 mm or less, more preferably 25 mm or less. 20 mm or less is most preferable. About the crack of an edge part, it is preferable that there is no crack or the length of a crack is less than 1 mm on average. This crack resistance is an important characteristic for preventing crack defects in handling such as coating, processing, cutting, and sticking of a film having a cured layer.

[Coating method]
The antireflection film of the present invention can be formed by the following method, but is not limited to this method.
First, a coating solution containing components for forming each layer is prepared. The coating solution is applied onto the transparent substrate film by dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating or extrusion coating (see US Pat. No. 2,681,294). Apply, heat and dry. Of these coating methods, coating by gravure coating is preferable because a coating solution with a small coating amount such as each layer of the antireflection film can be applied with high film thickness uniformity. Among the gravure coating methods, the micro gravure method has a high film thickness uniformity and is more preferable.
In addition, a coating solution with a small coating amount can be applied with high film thickness uniformity even by using a die coating method. Further, since the die coating method is a pre-measuring method, film thickness control is relatively easy, and the solvent in the coating part Is preferred because of less transpiration. As a method for applying a thin layer coating solution having a wet film thickness of several tens of microns or less to a plastic film using a specific slot die or a coating method, for example, Japanese Patent Application Laid-Open Nos. 2003-200097, 2003-211052, and 2003 No. 230862, No. 2003-236434, No. 2003-236451, No. 2003-245595, No. 2003-251260, No. 2003-260400, No. 2003-260402, No. 2003-275562, No. 2004-141806 The methods described in the above publications are also preferable. Two or more layers may be applied simultaneously. The method of simultaneous application is described in US Pat. Nos. 2,761,791, 2,941,898, 3,508,947, and 3,526,528 and Yuji Harasaki, Coating Engineering, page 253, Asakura Shoten (1973).

[Polarizer]
The antireflection film of the present invention can also be used as a protective layer (hereinafter also referred to as “protective film”) for polarizing plates such as LCDs. When used as a protective layer, a low moisture-permeable cured layer and an antireflection layer according to the present invention are formed on one side of a cellulose acylate film (such as TAC) and then alkaline (for example, 1.0 to 3.0 mol / The TAC is saponified by immersing it in a (liter sodium hydroxide aqueous solution) bath. After neutralization and washing with water, the TAC surface is bonded to a polarizer (made of polyvinyl alcohol, iodine, boric acid) with a polyvinyl alcohol adhesive. The cellulose acylate film subjected to the saponification treatment and the polarizer are firmly bonded to each other, which is superior to the case of using the norbornene resin disclosed in JP-A-10-101907. Moreover, since the low moisture-permeable cured layer concerning this invention is formed, deterioration of a polarizer can be suppressed because moisture permeability is small.

[Image display device]
The image display device of the present invention is characterized in that the antireflection film of the present invention described above or a polarizing plate having the antireflection film as a protective layer is disposed on the image display surface. Thus, the antireflection film of the present invention or the polarizing plate having the antireflection film as a protective film can be applied to an image display device such as a liquid crystal display device (LCD) or an organic EL display. The image display device of the present invention is preferably applied to a transmissive, reflective, or transflective liquid crystal display device in any one of TN, STN, IPS, VA, and OCB modes. This will be further described below.

  Any conventionally known liquid crystal display device can be used. For example, supervised by Tatsuo Uchida, “Reflective Color LCD Comprehensive Technology” [CMC, 1999], “New Development of Flat Panel Display” [Toray Research Center, Inc., Research Division, 1996], “Liquid Crystal Related Markets” And the future prospects (first volume), (second volume) "[Fuji Chimera Research Institute, Inc., published in 2003], and the like.

  Specifically, for example, a transmissive type or a reflective type such as twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically compensated bend cell (OCB), etc. It can be preferably used for a liquid crystal display device of a type or a transflective type.

  In addition, the antireflection film of the present invention has a good contrast and a wide viewing angle even when the size of the attached display image of the liquid crystal display device is 17 inches or more, and prevents hue change and transfer of external light. Is preferable.

<TN mode liquid crystal display device>
The TN mode liquid crystal cell is most frequently used as a color TFT liquid crystal display device, and many publications are cited. The alignment state in the liquid crystal cell in the TN mode black display is an alignment state in which the rod-like liquid crystalline molecules rise at the center of the cell and the rod-like liquid crystalline molecules lie in the vicinity of the cell substrate.

<OCB mode liquid crystal display device>
The OCB mode liquid crystal cell is a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between an upper portion and a lower portion of the liquid crystal cell. Since the liquid crystal display device using the bend alignment mode liquid crystal cell is aligned symmetrically between the upper part and the lower part of the liquid crystal cell, the devices disclosed in the specifications of US Pat. Nos. 4,583,825 and 5,410,422 are provided. The bend alignment mode liquid crystal cell has a self-optical compensation function. For this reason, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode.

  Similarly to the TN mode, the liquid crystal cell in the OCB mode is in a black display, and the alignment state in the liquid crystal cell is such that the rod-like liquid crystal molecules rise in the center of the cell and the rod-like liquid crystal molecules lie in the vicinity of the cell substrate. .

<VA mode liquid crystal display device>
In a VA mode liquid crystal cell, rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied.

  The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). (2) In addition to the liquid crystal cell [SID97, Digest of Tech. Papers 28 (1997) 845], (3) Liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied. [Preliminary collections 58-59 (1998) of the Japanese Liquid Crystal Discussion Group] and (4) SURVAVAL mode liquid crystal cells (presented at LCD International 98).

<IPS mode liquid crystal display device>
In the IPS mode liquid crystal cell, the liquid crystal molecules are always rotated in a horizontal plane with respect to the substrate, and the liquid crystal molecules are aligned to have a slight angle with respect to the longitudinal direction of the electrode when no electric field is applied. When an electric field is applied, the liquid crystal molecules change direction in the direction of the electric field. The light transmittance can be changed by arranging the polarizing plates sandwiching the liquid crystal cell at a predetermined angle. As the liquid crystal molecules, nematic liquid crystal having a positive dielectric anisotropy Δε is used. The thickness (gap) of the liquid crystal layer is more than 2.8 μm and less than 4.5 μm. This is because when the retardation Δn · d is more than 0.25 μm and less than 0.32 μm, a transmittance characteristic having almost no wavelength dependency within the visible light range can be obtained. By combining with a polarizing plate, the maximum transmittance can be obtained when the liquid crystal molecules are rotated 45 ° from the rubbing direction to the electric field direction. The thickness (gap) of the liquid crystal layer is controlled by polymer beads. Of course, the same gap can be obtained even with glass bead fiber and resin columnar spacers. The liquid crystal molecules are not particularly limited as long as they are nematic liquid crystals. The larger the value of the dielectric anisotropy Δε, the lower the drive voltage. When the refractive index anisotropy Δn is small, the thickness (gap) of the liquid crystal layer can be increased, the liquid crystal sealing time can be shortened, and the gap variation can be reduced.

<Other LCD mode>
The STN mode liquid crystal display device can be provided with the polarizing plate of the present invention in the same manner as described above. The same applies to the ECB mode.

  Further, by combining the antireflection film of the present invention with a λ / 4 plate, it can be used as a polarizing plate for reflective liquid crystal or a surface protective plate for organic EL display to reduce reflected light from the surface and inside. it can.

  The present invention will be specifically described based on examples, but the present invention is not limited to the examples (in the following examples, “part” represents “part by mass”).

(Preparation of coating liquid H-1 for forming a low moisture-permeable cured layer)
Compound K-5 4.85 g
(Kyarad R-684, manufactured by Nippon Kayaku Co., Ltd.)
MEK (methyl ethyl ketone) 4.50g
Cyclohexanone 0.50g
Photoradical polymerization initiator 0.15g
(Irgacure 907, manufactured by Ciba Geigy)
Were mixed and stirred to obtain a hard coat coating solution.

(Preparation of low moisture-permeable cured layer forming coating solution H-2)
Compound K-5 3.88 g
(Kyarad R-684, manufactured by Nippon Kayaku Co., Ltd.)
Multifunctional acrylate DPCA-20 (Nippon Kayaku Co., Ltd.) 0.97g
MEK (methyl ethyl ketone) 4.50g
Cyclohexanone 0.50g
Photoradical polymerization initiator 0.15g
(Irgacure 907, manufactured by Ciba Geigy)
Were mixed and stirred to obtain a hard coat coating solution.

(Preparation of low moisture permeability cured layer formation H-3)
Compound K-5 2.91 g
(Kyarad R-684, manufactured by Nippon Kayaku Co., Ltd.)
DPCA-20 (Nippon Kayaku Co., Ltd.) 1.94g
MEK (methyl ethyl ketone) 4.50g
Cyclohexanone 0.50g
Photoradical polymerization initiator 0.15g
(Irgacure 907, manufactured by Ciba Geigy)
Were mixed and stirred to obtain a hard coat coating solution.

(Preparation of hard coat layer forming coating solution H-4)
DPCA-20 (Nippon Kayaku Co., Ltd.) 4.85g
MEK (methyl ethyl ketone) 4.50g
Cyclohexanone 0.50g
Photoradical polymerization initiator 0.15g
(Irgacure 907, manufactured by Ciba Geigy)
Were mixed and stirred to obtain a hard coat coating solution.

(Preparation of high refractive index coating liquid A)
Desolite Z7404 (zirconia fine particle-containing hard coat composition, manufactured by JSR Corporation) 100 parts by mass, DPHA (UV curable resin: manufactured by Nippon Kayaku Co., Ltd.) 31 parts by mass, KBM-5103 (silane coupling agent: Shin-Etsu) (Chemical Industry Co., Ltd.) 10 parts by mass, 29 parts by mass of methyl ethyl ketone, 13 parts by mass of methyl isobutyl ketone, and 5 parts by mass of cyclohexanone were placed in a mixing tank and stirred to obtain a high refractive index coating liquid A.

(Preparation of coating solution for low refractive index layer)
(Preparation of sol solution a)
A stirrer, a reactor equipped with a reflux condenser, 120 parts of methyl ethyl ketone, 100 parts of acryloyloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts of diisopropoxyaluminum ethyl acetoacetate were added and mixed. Thereafter, 30 parts of ion-exchanged water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature to obtain sol solution a. The mass average molecular weight was 1600, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all. A sol solution a was prepared with methyl ethyl ketone so that the solid content concentration was 29%.

(Preparation of dispersion A-1)
Hollow silica fine particle sol (Isopropyl alcohol silica sol, average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20% by mass, silica particle refractive index 1.31, change the size according to [Preparation Example 4] of JP-A-2002-79616. 500 parts, 30 parts of acryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) and 1.5 parts of diisopropoxyaluminum ethyl acetate were added and mixed, and then 9 parts of ion-exchanged water was added. . After reacting at 60 ° C. for 8 hours, the mixture was cooled to room temperature, and 1.8 parts of acetylacetone was added. While adding cyclohexanone to 500 g of this dispersion so that the silica content was almost constant, solvent substitution was performed by distillation under reduced pressure at a pressure of 20 kPa. There was no generation of foreign matter in the dispersion, and the viscosity when the solid content concentration was adjusted to 20% by mass with cyclohexanone was 5 mPa · s at 25 ° C. When the residual amount of isopropyl alcohol in the obtained dispersion A-1 was analyzed by gas chromatography, it was 1.5%.

(Preparation of coating solution for low refractive index layer (L-1))
Dispersion A-1 with respect to 783.3 parts by mass (47.0 parts by mass as the solid content) of OPSTAR JTA113 (thermally crosslinkable fluorine-containing silicone polymer composition liquid (solid content: 6%): manufactured by JSR Corporation) 195 parts by mass (silica + 39.0 parts by mass as surface treatment agent solids), colloidal silica dispersion (silica, MEK-ST particle size difference, average particle size 45 nm, solid content concentration 30%, Nissan Chemical ( 30.0 parts by mass (9.0 parts by mass as solids) and 17.2 parts by mass of sol liquid a (5.0 parts by mass as solids) were added. The coating liquid (L-1) was prepared by diluting with cyclohexane and methyl ethyl ketone so that the solid content concentration of the entire coating liquid was 6% by mass and the ratio of cyclohexane and methyl ethyl ketone was 10:90.

(Preparation of coating solution for low refractive index layer (L-2))
Opstar JTA113 (thermally crosslinkable fluorine-containing silicone polymer composition liquid (solid content: 6%): manufactured by JSR Corporation) 941.7 parts by mass (56.5 parts by mass as solids), colloidal silica dispersion ( Silica, MEK-ST particle size difference product, average particle size 45 nm, solid content concentration 30%, manufactured by Nissan Chemical Co., Ltd.) 100.0 parts by mass (30.0 parts by mass as solids), sol solution a46.6 Part by mass (13.5 parts by mass as a solid content) was added. The coating liquid (L-2) was prepared by diluting with cyclohexane and methyl ethyl ketone so that the solid content concentration of the entire coating liquid was 6% by mass and the ratio of cyclohexane and methyl ethyl ketone was 10:90.

(Preparation of antireflection film 001)
(1) The above H-1 was coated with a # 6 bar on a cellulose acetate film (Fujitac TD80, 80 μm thickness, manufactured by Fuji Photo Film Co., Ltd.). After drying at 70 ° C. for 2 minutes, it was cured by irradiation with ultraviolet rays (100 mJ / cm ² ) in a nitrogen atmosphere. The film thickness of the obtained low moisture-permeable cured layer was 4.6 μm.
(2) The film having the low moisture-permeable cured layer is conveyed using a microgravure roll with a diameter of 50 mm having a gravure pattern of 135 lines / inch and a depth of 60 μm and a doctor blade. After coating at a speed of 10 m / min and drying at 60 ° C. for 150 seconds, the coating layer was cured by irradiating with an ultraviolet ray with a dose of 100 mJ / cm ² under a nitrogen purge. The rotation speed of the gravure roll was adjusted so that the thickness of the high refractive index layer after curing was 4.0 μm.
(3) An antireflection film 001 was produced by adjusting the film thickness of the low refractive index layer to 90 nm using the coating liquid for low refractive index layer (L-1). The drying condition of the low refractive index layer was 110 ° C. for 10 minutes, and the ultraviolet curing condition was an irradiation amount of 240 mJ / cm ² while purging with nitrogen so that the atmosphere had an oxygen concentration of 0.01% by volume or less.

(Preparation of antireflection films 002 and 003)
Antireflection films 002 and 003 were produced in the same manner as the antireflection film 001 using the coating liquids H-2 to H-3 for forming a low moisture permeability cured layer and the coating liquid L-1 for a low refractive index layer. The contents are shown in the table.

(Preparation of antireflection film 004 (comparative sample))
An antireflection film 004 (comparative sample) was produced in the same manner as the antireflection film 001 using the coating liquid H-4 for forming a hard coat layer and the coating liquid L-1 for a low refractive index layer. The contents are shown in the table.

(Preparation of antireflection film 005)
An antireflection film 005 was produced in the same manner as the antireflection film 001 using the coating liquid H-1 for forming a low moisture permeability cured layer and the coating liquid L-2 for a low refractive index layer. The contents are shown in the table.

An adhesive (SK-2057, manufactured by Soken Chemical Co., Ltd.) is bonded to the cellulose acetate side of the antireflective film 001 of the present invention and the antireflective film 004 of the comparative sample, and further a PET film for a separator (100 μm) is further formed thereon. Were pasted together.
When this film was allowed to stand for 24 hours in an environment at 25 ° C. and a relative humidity of 80%, and then only the relative humidity was set to 10%, the curl value defined in Formula B was 7 in the case of the antireflection film 001 of the present invention. . On the other hand, it was 31 in the case of the antireflection film 004 of the comparative sample.
In addition, the antireflection film using 001 having a small curl value is excellent in handling properties, but the antireflection film using 004 has poor handling properties.

(Preparation of polarizing plate)
(Saponification treatment)
A 1.5 mol / L aqueous sodium hydroxide solution was prepared and kept at 50 ° C. A 0.005 mol / L dilute sulfuric acid aqueous solution was prepared.
The antireflection film 001 was immersed in the aqueous sodium hydroxide solution for 2 minutes, and then immersed in water to sufficiently wash away the aqueous sodium hydroxide solution. Subsequently, after being immersed in the above-mentioned dilute sulfuric acid aqueous solution for 1 minute, it was immersed in water to sufficiently wash away the dilute sulfuric acid aqueous solution and sufficiently dried at 100 ° C. Thus, the single side | surface saponification processing film by which the cellulose acetate film side was saponified was obtained.

(Production of polarizer)
Polyvinyl alcohol casting Polyvinyl alcohol (PVA) having an average polymerization degree of 4000 and a saponification degree of 99.8 mol% was dissolved in water to obtain a 4.0% aqueous solution. This solution was cast and dried, peeled off from the band, and an unstretched polyvinyl alcohol film was obtained.
・ Iodine impregnation Unstretched polyvinyl alcohol film was immersed in an aqueous solution of 2.0 g / liter of iodine and 4.0 g / liter of potassium iodide at 25 ° C. for 240 seconds, and further 60 ° C. in an aqueous solution of boric acid 10 g / liter at 25 ° C. After dipping for 2 seconds, it was washed with water at 20 ° C. for 10 seconds in a water washing tank.
Stretching The iodine impregnated film was stretched 5.3 times at 80 ° C. without being dried.
After stretching, the film was dried at 80 ° C. for 5 minutes to obtain a long polarizer. The thickness was 20 μm.

(Attachment of protective film for polarizing plate)
Using a polarizer with a 3% by weight aqueous solution of polyvinyl alcohol (PVA-117H, manufactured by Kuraray Co., Ltd.) as an adhesive, one sheet is an antireflective film 001, and a cellulose acetate film (Fujitac TD80 is saponified on the opposite side) ) Was attached. In addition, the adhesion surface with the polarizer of the antireflection film 001 is the triacetyl cellulose side. This polarizing plate was adhered to a glass plate using an adhesive (SK-2057, manufactured by Soken Chemical Co., Ltd.) to obtain a test sample.
In the same manner as described above, test samples were also prepared for the antireflection films 002 to 005.

(Measurement of degree of polarization)
The polarizing plate obtained as described above was left in an environment of 60 ° C. and 95% for 1000 hours, and the degree of polarization was measured. The degree of polarization can be obtained from the following equation. (Wavelength 550nm)
In this example, the degree of polarization was measured using a spectrophotometer (MPC-3100, manufactured by Shimadzu Corporation).

Evaluation of polarization degree There is no problem when the polarization degree is 99% or more. ○
There is no practical problem when the degree of polarization is 98% or more and less than 99%. △
The degree of polarization is less than 98%, which is a problem. ×

(Measurement of average reflectance)
Using a spectrophotometer (manufactured by JASCO Corporation; V-550), spectral reflectance at an incident angle of 5 ° was measured using an integrating sphere in a wavelength region of 380 to 780 nm. In the evaluation of the average reflectance, an average reflectance of 450 to 650 nm was used.
In addition, the measurement sample used what was processed into the polarizing plate.

(Magic wipeability evaluation)
Magic ink No. 700 (black, manufactured by Teranishi Chemical Industry Co., Ltd.) was used to draw and paint a circle having a diameter of 1 cm on the antireflection film sample. The sample was first dried at 25 ° C. and 55% relative humidity for 30 minutes and then allowed to stand at 40 ° C. and 80% relative humidity for 24 hours. Thereafter, the sample was taken out under conditions of 25 ° C. and 55%, allowed to stand for 30 minutes or more, and then rubbed with Bencot (manufactured by Asahi Kasei Co., Ltd.) to evaluate whether or not the magic was wiped off.
○: Even if you look very carefully, you can't see any magic marks.
○ △: A trace of magic is visible.
Δ ×: A mark that does not disappear is detected.
×: Can hardly be wiped off.

(Moisture permeability)
The moisture permeability (g / m ² · day) of the obtained antireflection film sample was measured according to JIS-Z-0208 (however, 60 ° C., 95% relative humidity).

(Steel wool scratch resistance evaluation)
A rubbing test was performed using a rubbing tester under the following conditions.
Evaluation environmental conditions: 25 ° C., 60% RH
Rubbing material: Steel wool “No. 0000” (manufactured by Nippon Steel Wool Co., Ltd.) was wound around the tip (1 cm × 1 cm) of the rubbing of the tester that was in contact with the sample, and the band was fixed so as not to move.
Moving distance (one way): 13 cm, rubbing speed: 13 cm / sec, load: 500 g / cm ² , tip contact area: 1 cm × 1 cm, rubbing frequency: 10 reciprocations.

An oil-based black ink was applied to the back side of the rubbed sample and visually observed with reflected light, and scratches on the rubbed portion were evaluated according to the following criteria.
○: Even when viewed very carefully, no scratches are visible.
○ △: Slightly weak scratches are seen when viewed very carefully.
Δ: A weak scratch is visible.
Δ ×: moderate scratches are visible.
X: There are scratches that can be seen at first glance.

  As shown above, the antireflection film of the present invention has low moisture permeability, small curl, and excellent scratch resistance, antireflection effect and antifouling property. Moreover, it turned out that the polarizing plate which comprised the antireflection film of this invention was excellent in durability under high temperature and humidity.

  The polarizing plate using the antireflection film 001 of the present invention was bonded to a liquid crystal panel (CR-L26WA manufactured by LG Electronics Japan) from which the polarizing plate was peeled off using an adhesive. Similarly, the antireflection films 004 and 005 were bonded to the liquid crystal panel. When the reflected light of the fluorescent lamp was visually observed, the reflection of the fluorescent lamp was good for both 001, 004 and 005. In particular, those using 001,004 were excellent. When the low refractive index layer was not laminated, the reflection of the fluorescent lamp was conspicuous and hindered viewing of the image.

Claims (10)

On the transparent substrate film, at least a low moisture permeability cured layer and a low refractive index layer are laminated in this order, and the moisture permeability measured in an atmosphere of 60 ° C. and 95% relative humidity in accordance with JIS-Z-0208 is 1000 g. An antireflection film characterized by being less than / m ² · day.   The antireflection film according to claim 1, wherein a refractive index of the low refractive index layer is 1.46 or less. The low moisture permeability cured layer is
A curable composition containing at least one compound selected from the compound represented by the following general formula (A) and the compound represented by the following general formula (B) is coated and dried on a transparent substrate film, The antireflection film according to claim 1, wherein the antireflection film is obtained by curing the same.
Formula (A)

(Wherein R1 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R2 is an alkylene group or alkylene oxide group having 1 to 5 carbon atoms, R3 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n is 1 or An integer of 2)
General formula (B)

(Wherein R1, R3 and n have the same meaning as in the above general formula (A))   The low refractive index layer contains a component having an alkyl fluoride portion, and hollow silica fine particles having a particle size of 20 to 100 nm and a refractive index of 1.40 or less. The antireflection film according to any one of the above.   The low-refractive index layer contains a component having a dialkylsiloxane part, and hollow silica fine particles having a particle size of 20 to 100 nm and a refractive index of 1.40 or less. The antireflection film according to any one of the above.   The antireflection film according to claim 1, wherein the transparent substrate film is a cellulose acylate.   The antireflection film according to claim 1, wherein the cellulose acylates are cellulose acetate, cellulose acetate propionate, or cellulose acetate butyrate.   The film thickness of the said low moisture-permeable cured layer is 1-10 micrometers, The antireflection film in any one of Claims 1-7 characterized by the above-mentioned.   A polarizing plate comprising the antireflection film according to claim 1 as a protective layer for a polarizer.   An image display device comprising the polarizing plate according to claim 9.