JP2005301246A - Antireflection film, polarizing plate, and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection film which will not cause white blurs, image blurs, and garish phenomenon, a polarizing plate which has high visibility and a larger field angle (specially, a downward field angle) and is nearly free of contrast decrease, gradation or black-and-white inversion, color phase variation, etc., due to field angle variation, and to provide a liquid crystal display which uses the antireflection film and polarizing plate. <P>SOLUTION: The antireflection film has a hard coat layer and a low-refractive-index layer on a transparent base, and the hard coat layer contains a binder and translucent particles having a different refractive index from the binder; and the antireflection film has ≤0.10 μm surface roughness Ra, and the low-refractive-index layer contains hollow silica particulates of 5 to 200 nm in mean particle size and 1.17 to 1.40 in refractive index. The polarizing plate uses this antireflection film as one protective film, and the liquid crystal display device uses the antireflection film or polarizing plate for the outermost layer of a display. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display element used for image display such as a computer, a word processor, and a television, and more particularly to an antireflection film, a polarizing plate, and a liquid crystal display device for improving display quality.

  In general, an antireflection film is used in a display device such as a cathode ray tube display (CRT), a plasma display (PDP), an electroluminescence display (ELD), or a liquid crystal display (LCD) to reduce contrast or reduce an image due to reflection of external light. In order to prevent reflection and improve the visibility of the image, it is placed on the outermost surface of the display using the principle of light diffusion and optical interference.

As a conventional antireflection film, there is an antiglare antireflection film that suppresses regular reflection of external light and diffuses external environment by diffusing surface reflection light. For example, in the antireflection film of Patent Document 1, appropriate fine particles are contained in the hard coat layer to give unevenness to the surface to diffuse external light, thereby reducing the glare of the screen. In addition, in the antireflection films of Patent Documents 2 and 3, a low refractive index layer is provided on an antiglare hard coat layer having a fine surface roughness, and in addition to the diffusion of external light on the surface, the light interference The reflectivity is suppressed using the principle. Furthermore, in the antireflection film of Patent Document 4, a high refractive index layer is provided under the low refractive index layer, and light interference is effectively used to reduce external light reflection.
However, these antiglare antireflection films diffuse external light with fine irregularities on the surface, and at the same time, the display screen becomes white (white blurring), and the sharpness of the image decreases (image blurring). However, the problem of glare caused by the lens effect of the fine uneven structure is inevitable. For these problems, attempts have been made to improve the antiglare layer by controlling the haze, image definition, fine unevenness, etc., but satisfactory results have not been obtained.

  On the other hand, an antireflection film having a very small surface unevenness or a flat surface has been proposed as an antireflection film having high image clarity and no white blurring or glare phenomenon. Patent Document 5 proposes an antireflection film in which a laminated structure is formed in the order of a medium refractive index layer, a high refractive index layer, and a low refractive index layer on a base film, and there is no surface fine uneven structure and only optical interference is used. ing. Further, Patent Document 6 proposes an antireflection film capable of improving the viewing angle characteristics while providing a sharp image by imparting internal scattering to the hard coat layer while keeping the surface roughness very small. However, the refractive index of the low refractive index layer on the outermost surface is not so low, and the level of visibility in the bright room is still not satisfactory.

Attempts have also been made to increase the antireflection performance by lowering the refractive index of the outermost low refractive index layer. Conventionally, in order to lower the refractive index of the layer, means have been taken to increase the fluorine content of the material used or to reduce the density in the layer, such as introducing voids. This causes a problem that the adhesion to the resin is impaired and the scratch resistance is lowered. Therefore, in Patent Document 7, a low refractive index layer containing hollow silica fine particles is coated on a hard coat layer having a smooth surface that does not contain any particles, thereby preventing reflection by reducing the refractive index of hollow silica. An antireflection film has been proposed that improves the properties and also improves the film strength by the strength of hollow silica.
However, in recent years, various displays have been used in various environments, and there has been a higher level of demand for display quality. However, in addition to these performances, it is difficult to say that it has been achieved at a high level at the same time in terms of image clarity and viewing angle characteristics.

JP 2000-338310 A JP 2002-196117 A JP 2003-161816 A JP 2003-121620 A JP 2003-75603 A JP 2002-317152 A JP 2003-57415 A

An object of the present invention is to improve the visibility of a display such as a liquid crystal display device, thereby preventing reflection of external light, no whitening, image blurring, or glare, and anti-reflection with improved scratch resistance. To provide a film.
Another object of the present invention is that the antireflection film has a high degree of visibility, further increases the viewing angle (particularly the downward viewing angle), and reduces contrast, gradation or black-and-white reversal, and hue due to changes in viewing angle. An object of the present invention is to provide a polarizing plate that hardly undergoes changes and the like, and a liquid crystal display device using the polarizing plate.

The above objects of the present invention are achieved by the following antireflection films 1 to 5, the following polarizing plates 6 and 7, and the following liquid crystal display device 8.
1. An antireflection film having, on a transparent support, at least one hard coat layer and a low refractive index layer located on the outermost layer,
(I) The hard coat layer contains a binder and at least one kind of translucent particles having a refractive index different from that of the binder,
(Ii) The surface roughness Ra (centerline average roughness) of the antireflection film is 0.10 μm or less, and (iii) the low refractive index layer has an average particle diameter of 5 to 200 nm and a refractive index. Contains hollow silica fine particles having 1.17 to 1.40,
An antireflection film characterized by that.
2. 2. The antireflection film as described in 1 above, wherein the transmitted image definition of the antireflection film is 60% or more.
3. 3. The antireflection film as described in 1 or 2 above, wherein the haze is 10% or more.
4). 1 above, wherein the scattered light intensity at an output angle of 30 ° with respect to the light intensity at an output angle of 0 ° of the scattered light profile measured with a goniophotometer of the hard coat layer is 0.01% to 0.2%. The antireflection film according to any one of to 3.
5). 5. The antireflection film as described in any one of 1 to 4 above, which has at least one high refractive index layer having a higher refractive index than that of the transparent support on the hard coat layer.
6). A polarizing plate having both surfaces of a polarizing film sandwiched between protective films, wherein the antireflection film according to any one of the above 1 to 5 is used for one protective film.
7. The protective film in which the antireflection film is not used among the two protective films is an optical compensation film having an optically anisotropic layer, and the optically anisotropic layer contains a compound having a discotic structural unit. The disc surface of the discotic structural unit is inclined with respect to the protective film surface, and the angle formed by the disc surface of the discotic structural unit and the protective film surface changes in the depth direction of the optical anisotropic layer. 7. The polarizing plate as described in 6 above, wherein
8). 6. A liquid crystal display device comprising the antireflection film according to any one of 1 to 5 or the polarizing plate according to any one of 6 and 7 as an outermost layer of a display.

According to the present invention, reflection of external light can be prevented, the visibility of a display such as a liquid crystal display device free from white blurring, image blurring, and glare can be improved, and anti-reflection with improved scratch resistance. A film can be provided.
The antireflection film of the present invention can be used as a protective film for a polarizing plate. The antireflection film and polarizing plate of the present invention have a high degree of visibility when used in a liquid crystal display device. Further, the viewing angle, in particular, the downward viewing angle is enlarged, and the contrast is lowered due to the change in viewing angle. Alternatively, it is possible to provide a liquid crystal display device in which black-white inversion, hue change, and the like hardly occur.

Hereinafter, first, embodiments of the antireflection film of the present invention will be described with reference to the drawings.
1-3, the structural example of the antireflection film of this invention is typically shown with sectional drawing. As shown in FIG. 1, the antireflection film 10 of the present invention contains a transparent support 1, a hard coat layer 2A containing translucent particles 4A capable of imparting internal scattering properties, and hollow silica fine particles in the outermost layer. The low refractive index layer 3 is laminated. The mode of each layer and the layer configuration of the film can be changed as appropriate. For example, as shown in the antireflection film 20 of FIG. 2, the hard coat layer 2B further contains other kinds of translucent particles 4B. Alternatively, as shown in the antireflection film 30 of FIG. 3, a medium refractive index layer 5 and a high refractive index layer 6 are provided on the hard coat layer 2A for the purpose of enhancing the antireflection property due to light interference. The low refractive index layer 3 may be disposed as the outermost layer.

Next, each layer constituting the antireflection film of the present invention will be described in detail. In the present specification, the description “(numerical value A) to (numerical value B)” representing a physical property value or a characteristic value means “(numerical value A) or more and (numerical value B) or less”.
(Transparent support)
The transparent support of the antireflection film of the present invention is not particularly limited, such as a transparent resin film, a transparent resin plate, a transparent resin sheet, and transparent glass. Transparent resin films include cellulose acylate films (for example, cellulose triacetate film (refractive index 1.48), cellulose diacetate film, cellulose acetate butyrate film, cellulose acetate propionate film), polyethylene terephthalate film, polyethersulfone. Films, polyacrylic resin films, polyurethane resin films, polyester films, polycarbonate films, polysulfone films, polyether films, polymethylpentene films, polyetherketone films, (meth) acrylonitrile films, and the like can be used.
Among them, a cellulose acylate film having high transparency, optically low birefringence, easy production, and generally used as a protective film for a polarizing plate is preferable, and a cellulose triacetate film is particularly preferable. The thickness of the transparent support is usually about 25 μm to 1000 μm.

For the cellulose acylate film of the present invention, it is preferable to use cellulose acetate having an acetylation degree of 59.0 to 61.5%.
The degree of acetylation means the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation follows the measurement and calculation of the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like).
The viscosity average degree of polymerization (DP) of cellulose acylate is preferably 250 or more, and more preferably 290 or more.
The cellulose acylate used in the present invention has a Mw / Mn (Mw is a mass average molecular weight, Mn is a number average molecular weight) value by gel permeation chromatography close to 1.0, in other words, a molecular weight distribution. Narrow is preferred. The specific value of Mw / Mn is preferably 1.0 to 1.7, more preferably 1.3 to 1.65, and most preferably 1.4 to 1.6. preferable.

In general, the 2, 3, and 6 hydroxyl groups of cellulose acylate are not evenly distributed by 1/3 of the total substitution degree, and the substitution degree of the 6-position hydroxyl group tends to be small. In the present invention, it is preferable that the substitution degree of the 6-position hydroxyl group of cellulose acylate is larger than that of the 2- and 3-positions.
The hydroxyl group at the 6-position with respect to the total substitution degree is preferably substituted with 32% or more of an acyl group, more preferably 33% or more, and particularly preferably 34% or more. Furthermore, the substitution degree of the 6-position acyl group of cellulose acylate is preferably 0.88 or more. The 6-position hydroxyl group may be substituted with a propionyl group, butyroyl group, valeroyl group, benzoyl group, acryloyl group or the like, which is an acyl group having 3 or more carbon atoms, in addition to the acetyl group. The degree of substitution at each position can be determined by NMR.
As the cellulose acylate of the present invention, paragraphs “0043” to “0044” [Example] [Synthesis Example 1], paragraphs “0048” to “0049” [Synthesis Example 2], and paragraph “ Cellulose acetate obtained by the method described in “0051” to “0052” [Synthesis Example 3] can be used.

(Manufacture of cellulose acylate film)
The cellulose acylate film of the present invention can be produced by a solution casting method (solvent casting method). In the solvent cast method, a film is produced using a solution (dope) in which cellulose acylate is dissolved in an organic solvent.

  The organic solvent is a solvent selected from ethers having 3 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 3 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 6 carbon atoms. It is preferable to contain. Two or more organic solvents may be mixed and used.

  The ether, ketone and ester may have a cyclic structure. A compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and —COO—) can also be used as the organic solvent. The organic solvent may have another functional group such as an alcoholic hydroxyl group. In the case of an organic solvent having two or more types of functional groups, the preferred number of carbon atoms may be within the range of the preferred number of carbon atoms specified above for the compound having any functional group.

Examples of the ether having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole.
Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone.
Examples of the esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate.

  Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

  The number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, and most preferably 1. The halogen of the halogenated hydrocarbon is preferably chlorine. The proportion of halogenated hydrocarbon hydrogen atoms substituted with halogen is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and more preferably 35 to 65 mol%. More preferably, it is 40 to 60 mol%, and most preferably. Methylene chloride is a representative halogenated hydrocarbon.

The cellulose acylate solution (dope) can be prepared by a general method. The general method means that the treatment is performed at a temperature of 0 ° C. or higher (room temperature or high temperature). The solution can be prepared using a dope preparation method and apparatus in a normal solvent cast method. In the case of a general method, it is preferable to use a halogenated hydrocarbon (particularly methylene chloride) as the organic solvent. A non-chlorine solvent can also be used, and examples thereof include those described in the published technical report 2001-1745.
The amount of cellulose acylate is adjusted so that it is contained in an amount of 10 to 40% by mass in the resulting solution. The amount of cellulose acylate is more preferably 10 to 30% by mass. Arbitrary additives described later may be added to the organic solvent (main solvent).
The solution can be prepared by stirring cellulose acylate and an organic solvent at room temperature (0 to 40 ° C.). High concentration solutions may be stirred under pressure and heating conditions.
Specifically, the cellulose acylate and the organic solvent are placed in a pressure vessel and sealed, and stirred while being heated to a temperature equal to or higher than the boiling point of the solvent at normal temperature and in a range where the solvent does not boil. The heating temperature is usually 40 ° C. or higher, preferably 60 to 200 ° C., more preferably 80 to 110 ° C.

Each component may be coarsely mixed in advance and then placed in a container. Moreover, you may put into a container sequentially. The container needs to be configured so that it can be stirred. The container can be pressurized by injecting an inert gas such as nitrogen gas. Moreover, you may utilize the raise of the vapor pressure of the solvent by heating. Or after sealing a container, you may add each component under pressure.
When heating, it is preferable to heat from the outside of the container. For example, a jacket type heating device can be used. The entire container can also be heated by providing a plate heater outside the container and piping to circulate the liquid.
It is preferable to provide a stirring blade inside the container and stir using this. The stirring blade preferably has a length that reaches the vicinity of the wall of the container. A scraping blade is preferably provided at the end of the stirring blade in order to renew the liquid film on the vessel wall.
Instruments such as a pressure gauge and a thermometer may be installed in the container. Each component is dissolved in a solvent in the container. The prepared dope is taken out of the container after cooling, or taken out and then cooled using a heat exchanger or the like.

A solution can also be prepared by a cooling dissolution method. In the cooling dissolution method, cellulose acylate can be dissolved in an organic solvent that is difficult to dissolve by a normal dissolution method. In addition, even if it is a solvent which can melt | dissolve a cellulose acetate with a normal melt | dissolution method, there exists an effect that a uniform solution can be obtained rapidly according to a cooling melt | dissolution method.
In the cooling dissolution method, first, cellulose acylate is gradually added to an organic solvent at room temperature while stirring.
The amount of cellulose acylate is preferably adjusted so as to be contained in the mixture in an amount of 10 to 40% by mass. The amount of cellulose acylate is more preferably 10 to 30% by mass. Furthermore, you may add the arbitrary additive mentioned later in a mixture.

The mixture is then cooled to -100 to -10 ° C (preferably -80 to -10 ° C, more preferably -50 to -20 ° C, most preferably -50 to -30 ° C). The cooling can be performed, for example, in a dry ice / methanol bath (−75 ° C.) or a cooled diethylene glycol solution (−30 to −20 ° C.). When cooled in this way, the mixture of cellulose acetate and organic solvent solidifies.
The cooling rate is preferably 4 ° C./min or more, more preferably 8 ° C./min or more, and most preferably 12 ° C./min or more. The faster the cooling rate, the better. However, 10,000 ° C./second is the theoretical upper limit, 1000 ° C./second is the technical upper limit, and 100 ° C./second is the practical upper limit. The cooling rate is a value obtained by dividing the difference between the temperature at the start of cooling and the final cooling temperature by the time from the start of cooling to the final cooling temperature.

Furthermore, when this is heated to 0 to 200 ° C. (preferably 0 to 150 ° C., more preferably 0 to 120 ° C., most preferably 0 to 50 ° C.), cellulose acetate is dissolved in the organic solvent. The temperature can be raised by simply leaving it at room temperature or in a warm bath.
The heating rate is preferably 4 ° C./min or more, more preferably 8 ° C./min or more, and most preferably 12 ° C./min or more. The higher the heating rate, the better. However, 10,000 ° C./second is the theoretical upper limit, 1000 ° C./second is the technical upper limit, and 100 ° C./second is the practical upper limit. The heating rate is a value obtained by dividing the difference between the temperature at the start of heating and the final heating temperature by the time from the start of heating until the final heating temperature is reached. .
A uniform solution is obtained as described above. If the dissolution is insufficient, the cooling and heating operations may be repeated. Whether or not the dissolution is sufficient can be determined by merely observing the appearance of the solution with the naked eye.

In the cooling dissolution method, it is desirable to use a sealed container in order to avoid moisture mixing due to condensation during cooling. In the cooling and heating operation, if the pressure is applied during cooling and the pressure is reduced during heating, the dissolution time can be shortened. In order to perform pressurization and decompression, it is desirable to use a pressure-resistant container.
In addition, according to differential scanning calorimetry (DSC), a 20 mass% solution obtained by dissolving cellulose acetate (acetylation degree: 60.9%, viscosity average polymerization degree: 299) in methyl acetate by the cooling dissolution method is 33 There exists a quasi-phase transition point between a sol state and a gel state in the vicinity of ° C., and a uniform gel state is obtained below this temperature. Therefore, this solution needs to be maintained at a temperature equal to or higher than the pseudo phase transition temperature, preferably about 10 ° C. plus the gel phase transition temperature. However, this pseudo phase transition temperature varies depending on the degree of acetylation of cellulose acetate, the degree of viscosity average polymerization, the concentration of the solution, and the organic solvent used.

A cellulose acylate film is produced from the prepared cellulose acylate solution (dope) by a solvent cast method.
The dope is cast on a drum or band and the solvent is evaporated to form a film. It is preferable to adjust the concentration of the dope before casting so that the solid content is 18 to 35%. The surface of the drum or band is preferably finished in a mirror state. For casting and drying methods in the solvent casting method, U.S. Pat. It is described in each specification of JP 736892 A, Japanese Patent Publication Nos. 45-4554, 49-5614, and 62-1115035.
The dope is preferably cast on a drum or band having a surface temperature of 10 ° C. or less. After casting, it is preferable to dry it by applying air for 2 seconds or more. The obtained film can be peeled off from the drum or band and further dried with high-temperature air whose temperature is successively changed from 100 to 160 ° C. to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, it is possible to shorten the time from casting to stripping. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting.

  A film can also be produced by casting two or more layers by a solvent casting method using a plurality of prepared cellulose acylate solutions (dope). In this case, the dope is cast on a drum or band and the solvent is evaporated to form a film. The dope before casting is preferably adjusted in concentration so that the solid content is 10 to 40%. The surface of the drum or band is preferably finished in a mirror state.

  When casting a plurality of cellulose acylate liquids of two or more layers, it is possible to cast a plurality of cellulose acylate solutions, and cellulose is supplied from a plurality of casting openings provided at intervals in the traveling direction of the support. A film may be produced by casting and laminating a solution containing an acylate, for example, a method described in JP-A-61-158414, JP-A-1-122419, JP-A-11-198285, etc. Can be adapted. Further, it may be formed into a film by casting a cellulose acylate solution from two casting ports. For example, JP-B-60-27562, JP-A-61-94724, JP-A-61-104813, It can be carried out by the methods described in JP-A Nos. 61-158413 and 6-134933. Further, a cellulose acylate film flow in which a flow of a high-viscosity cellulose acylate solution described in JP-A-56-162617 is wrapped with a low-viscosity cellulose acylate solution and the high- and low-viscosity cellulose acylate solutions are simultaneously extruded. The extending method may be used.

  Alternatively, by using two casting ports, the film cast on the support is peeled off by the first casting port, and the second casting is performed on the side that is in contact with the support surface, so that the film is removed. For example, it is a method described in Japanese Patent Publication No. 44-20235. The cellulose acylate solutions to be cast may be the same solution or different cellulose acylate solutions, and are not particularly limited. In order to give a function to a plurality of cellulose acylate layers, a cellulose acylate solution corresponding to the function may be extruded from each casting port.

  Furthermore, in the present invention, the cellulose acylate solution is cast simultaneously with a solution for forming other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing layer, etc.) Simultaneous formation of the layer and film formation can also be carried out.

  In a single-layer solution, it is necessary to extrude a high-concentration and high-viscosity cellulose acylate solution to obtain the required film thickness. In this case, the stability of the cellulose acylate solution is poor and solids are generated. In many cases, however, it becomes a problem due to a failure or poor flatness. As this solution, a plurality of cellulose acylate solutions are cast from a casting port. As a result, it is possible to extrude a highly viscous solution onto the support at the same time, not only can the flatness be improved and an excellent planar film can be produced, but also a concentrated cellulose acylate solution can be used to reduce the drying load. Reduction can be achieved, and film production speed can be increased.

A plasticizer can be added to the cellulose acylate film in order to improve the mechanical properties or to improve the drying rate after casting during film production. As the plasticizer, phosphoric acid ester or carboxylic acid ester is used. Examples of phosphate esters include triphenyl phosphate (TPP), diphenyl biphenyl phosphate, and tricresyl phosphate (TCP). Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethylhexyl phthalate (DEHP). Examples of citrate esters include triethyl O-acetylcitrate (OACTE) and tributyl O-acetylcitrate (OACTB). Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phthalate plasticizers (DMP, DEP, DBP, DOP, DPP, DEHP) are preferably used. DEP and DPP are particularly preferred.
The addition amount of the plasticizer is preferably 0.1 to 25% by mass, more preferably 1 to 20% by mass, and most preferably 3 to 15% by mass of the amount of cellulose acylate.

  The cellulose acylate film may be added with an ultraviolet absorber and a deterioration inhibitor (eg, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine). The deterioration inhibitors are described in JP-A-3-199201, JP-A-597073, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854. The addition amount of the deterioration preventing agent is preferably 0.01 to 1% by mass of the solution (dope) to be prepared in consideration of the effect of the deterioration preventing agent and bleeding out (bleeding out) to the film surface. More preferably, the content is 0.01 to 0.2% by mass. Examples of particularly preferred deterioration inhibitors include butylated hydroxytoluene (BHT) and tribenzylamine (TBA). For these additives, use the compounds described in the lower column from the right column on page 16 to the left column on page 18 of JIII Journal of Technical Disclosure No. 2001-1745 (issued on March 15, 2001). Can do.

In the cellulose acylate film, a retardation increasing agent can be used as necessary in order to adjust the retardation of the film. The retardation of the film is preferably 0 to 300 nm in the film thickness direction and 0 to 1000 nm in the in-plane direction.
An aromatic compound having at least two aromatic rings is preferred as a retardation increasing agent, and the aromatic compound is used in an amount of 0.01 to 20 parts by mass with respect to 100 parts by mass of cellulose acylate. The aromatic compound is preferably used in the range of 0.05 to 15 parts by mass, more preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of cellulose acetate. Two or more aromatic compounds may be used in combination.
Details are described in JP-A Nos. 2000-1111914, 2000-275434, 2002-236215, PCT / JP00 / 02619, and the like.

(Stretching treatment of cellulose acylate film)
The produced cellulose acylate film can further improve drying unevenness, uneven film thickness caused by drying shrinkage, and surface unevenness by stretching treatment. The stretching treatment is also used for adjusting the retardation.
Although there is no limitation in particular in the method of the width direction extending | stretching process, the extending | stretching method by a tenter is mentioned as the example.
More preferably, the longitudinal stretching is performed in the longitudinal direction of the roll, and the longitudinal stretching is performed by adjusting the draw ratio of each pass roll (rotational ratio between the pass rolls) between the pass rolls that transport the roll film. Is possible.

(Surface treatment of cellulose acylate film)
The cellulose acylate film is preferably subjected to a surface treatment. Specific examples include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment, and ultraviolet irradiation treatment. In addition, as described in JP-A-7-333433, it is preferable to provide an undercoat layer.
From the viewpoint of maintaining the flatness of the film, the temperature of the cellulose acylate film in these treatments is preferably Tg or less, specifically 150 ° C. or less.
When the cellulose acylate film is adhered to the polarizing film as in the case of using the antireflection film of the present invention as a protective film for a polarizing plate, from the viewpoint of adhesiveness with the polarizing film, acid treatment or alkali treatment, that is, It is particularly preferable to carry out a saponification treatment on cellulose acylate.
From the viewpoint of adhesiveness and the like, the surface energy of the cellulose acylate film is preferably 55 mN / m or more, more preferably 60 mN / m or more and 75 mN / m or less, and it can be adjusted by the surface treatment. .
The surface energy of a solid can be determined by a contact angle method, a wet heat method, and an adsorption method as described in “Basics and Applications of Wetting” (issued by Realize 1989.12.10). In the case of the cellulose acylate film of the present invention, it is preferable to use a contact angle method.
Specifically, two kinds of solutions having known surface energies are dropped on the cellulose acylate film, and at the intersection between the surface of the droplet and the film surface, the angle formed between the tangent line drawn on the droplet and the film surface, The surface angle of the film can be calculated by defining the angle containing the droplet as the contact angle.

Hereinafter, the surface treatment will be specifically described with an alkali saponification treatment as an example.
The film surface is preferably immersed in an alkaline solution, then neutralized with an acidic solution, washed with water and dried.
Examples of the alkaline solution include potassium hydroxide solution and sodium hydroxide solution, and the concentration of these alkalis is preferably 0.1 mol / l to 3.0 mol / l, and preferably 0.5 mol / l to 2.0 mol. More preferably, it is / l. The alkaline solution temperature is preferably in the range of room temperature to 90 ° C, more preferably 40 ° C to 70 ° C.
From the viewpoint of productivity, it is preferable to apply an alkali solution and remove the alkali from the film surface by washing with water after saponification treatment. From the viewpoint of wettability, the coating solvent is preferably an alcohol such as IPA, n-butanol, methanol, and ethanol, and it is preferably used to add water, propylene glycol, ethylene glycol, or the like as an alkali dissolution aid.

(Hard coat layer)
The antireflection film of the present invention is provided with a hard coat layer on at least one surface of the transparent support in order to impart the physical strength of the film. In the present invention, a low refractive index layer is provided on the hard coat layer, and preferably an intermediate refractive index layer and a high refractive index layer are provided between the hard coat layer and the low refractive index layer. Construct a film.

  The antireflection film of the present invention must have a flat surface in order to improve white blurring, image blurring, and glare. Specifically, among the characteristics indicating the surface roughness, the center line average roughness (Ra) is set to 0.10 μm or less. Ra is more preferably 0.09 μm or less, and still more preferably 0.08 μm or less. In the antireflection film of the present invention, the surface unevenness of the hard coat layer is dominant in the surface unevenness of the film, and the center line average roughness of the hard coat layer is in the above range, whereby the center line of the antireflection film The average roughness can be in the above range.

The transmitted image definition of the antireflection film of the present invention is preferably 60% or more. The transmitted image clarity is generally an index indicating the degree of blurring of an image reflected through a film, and the larger this value, the clearer and better the image viewed through the film. The transmitted image definition is preferably 70% or more, and more preferably 80% or more.
Here, the transmitted image definition can be measured using an optical comb having a slit width of 0.5 mm with a image clarity measuring instrument (ICM-2D type) manufactured by Suga Test Instruments Co., Ltd. according to JIS K 7105.

  The refractive index of the hard coat layer of the present invention is preferably in the range of 1.48 to 2.00, more preferably 1.50 to 1, from the optical design for obtaining an antireflection film. .90, more preferably 1.50 to 1.80. In the present invention, since there is at least one low refractive index layer on the hard coat layer, if the refractive index is too small, the antireflection property is lowered, and if it is too large, the color of the reflected light tends to be strong. is there.

From the viewpoint of imparting sufficient durability and impact resistance to the film, the thickness of the hard coat layer is usually about 0.5 μm to 50 μm, preferably 1 μm to 20 μm, more preferably 2 μm. 10 μm, most preferably 3 μm to 7 μm.
Further, the strength of the hard coat layer is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test according to JIS K5400.
Furthermore, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound. For example, it may be formed by applying a coating composition containing an ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer on a transparent support and subjecting the polyfunctional monomer or polyfunctional oligomer to a crosslinking reaction or a polymerization reaction. it can.
The functional group of the ionizing radiation curable polyfunctional monomer or polyfunctional oligomer is preferably a light, electron beam, or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable.
Examples of the photopolymerizable functional group include unsaturated polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group is preferable.

As a specific example of a photopolymerizable polyfunctional monomer having a photopolymerizable functional group,
(Meth) acrylic acid diesters of alkylene glycol such as neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyoxyalkylene glycols such as triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyhydric alcohols such as pentaerythritol di (meth) acrylate;
(Meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts such as 2,2-bis {4- (acryloxy-diethoxy) phenyl} propane, 2-2-2bis {4- (acryloxy-polypropoxy) phenyl} propane ;
Etc.

  Furthermore, epoxy (meth) acrylates, urethane (meth) acrylates, and polyester (meth) acrylates are also preferably used as the photopolymerizable polyfunctional monomer.

  Among these, esters of polyhydric alcohol and (meth) acrylic acid are preferable. More preferably, a polyfunctional monomer having 3 or more (meth) acryloyl groups in one molecule is preferable. Specifically, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, 1,2,4-cyclohexanetetra (meth) acrylate, pentaglycerol triacrylate, pentaerythritol tetra (meth) acrylate, penta Erythritol tri (meth) acrylate, (di) pentaerythritol triacrylate, (di) pentaerythritol pentaacrylate, (di) pentaerythritol tetra (meth) acrylate, (di) pentaerythritol hexa (meth) acrylate, tripentaerythritol triacrylate , Tripentaerythritol hexatriacrylate and the like. In the present specification, “(meth) acrylate”, “(meth) acrylic acid”, and “(meth) acryloyl” represent “acrylate or methacrylate”, “acrylic acid or methacrylic acid”, and “acryloyl or methacryloyl”, respectively. .

Two or more polyfunctional 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 polymerization initiator or a thermal radical polymerization initiator.
As radical photopolymerization initiators, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds , Fluoroamine compounds, aromatic sulfoniums, lophine dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, coumarins and the like.

Examples of acetophenones include 2,2-dimethoxyacetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxy-dimethylphenylketone, 1-hydroxy-dimethyl-p-isopropylphenylketone, 1-hydroxy Cyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, 4-phenoxydichloroacetophenone, 4-t- Butyl-dichloroacetophenone.
Examples of benzoins include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl dimethyl ketal, benzoin benzene sulfonate, benzoin toluene sulfonate, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether It is.
Examples of benzophenones include benzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone, 4,4'-dimethylaminobenzophenone (Michler's ketone), 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone and the like.
Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
Examples of active esters include 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], sulfonic acid esters, cyclic active ester compounds, and the like.
Examples of onium salts include aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts.
Examples of the borate salts include ion complexes with cationic dyes.
Examples of active halogens include S-triazine and oxathiazol compounds,
2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p -Styrylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3-Br-4-di (ethyl acetate) amino) phenyl) -4,6-bis (trichloromethyl) -s -Triazine, 2-trihalomethyl-5- (p-methoxyphenyl) -1,3,4-oxadiazole.
Examples of inorganic complexes include bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium. It is done.
Examples of coumarins include 3-ketocoumarin.
These initiators may be used alone or in combination.
“Latest UV Curing Technology”, Technical Information Association, 1991, p. Various examples are also described in 159 and are useful in the present invention.

  Commercially available photo radical polymerization initiators include KAYACURE (DETX-S, BP-100, BDKM, CTX, BMS, 2-EAQ, ABQ, CPTX, EPD, ITX, QTX, BTC, manufactured by Nippon Kayaku Co., Ltd. MCA etc.), Irgacure (651, 184, 819, 500, 907, 369, 1173, 2959, 4265, 4263, etc.) manufactured by Ciba Specialty Chemicals Co., Ltd., Esacure (KIP100F, KB1, EB3, etc.) manufactured by Sartomer BP, X33, KT046, KT37, KIP150, TZT) and the like.

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. Examples of commercially available photosensitizers include KAYACURE (DMBI, EPA) manufactured by Nippon Kayaku Co., Ltd.
The photopolymerization reaction is preferably performed by ultraviolet irradiation after the hard coat layer is applied and dried.

As the thermal radical polymerization 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. Diazo compounds such as ammonium sulfate, potassium persulfate and the like, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (propionitrile), 1,1′-azobis (cyclohexanecarbonitrile), etc. And diazoaminobenzene, p-nitrobenzenediazonium and the like.

The polymer having a polyether as the main chain is preferably a ring-opening polymer of a polyfunctional epoxy compound. 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.
Accordingly, a coating liquid containing a polyfunctional epoxy compound, a photoacid generator or a thermal acid generator, translucent fine particles and an inorganic filler is prepared, and the coating liquid is applied onto a transparent support and then polymerized by ionizing radiation or heat. It can be cured by reaction to form a hard coat layer.

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.

  The binder in which the hard coat layer is crosslinked or polymerized has a structure in which the main chain of the polymer is crosslinked or polymerized. Examples of the polymer main chain include polyolefin (saturated hydrocarbon), polyether, polyurea, polyurethane, polyester, polyamine, polyamide and melamine resin. A polyolefin main chain, a polyether main chain and a polyurea main chain are preferable, a polyolefin main chain and a polyether main chain are more preferable, and a polyolefin main chain is most preferable.

  The polyolefin main chain is composed of a saturated hydrocarbon. The polyolefin main chain is obtained, for example, by an addition polymerization reaction of an unsaturated polymerizable group. The polyether main chain has repeating units bonded by an ether bond (—O—). The polyether main chain is obtained, for example, by a ring-opening polymerization reaction of an epoxy group. In the polyurea main chain, repeating units are bonded by a urea bond (—NH—CO—NH—). The polyurea main chain is obtained, for example, by a condensation polymerization reaction between an isocyanate group and an amino group. The polyurethane main chain has repeating units bonded by urethane bonds (—NH—CO—O—). The polyurethane main chain is obtained, for example, by a polycondensation reaction between an isocyanate group and a hydroxyl group (including an N-methylol group). The polyester main chain has repeating units bonded by an ester bond (—CO—O—). The polyester main chain is obtained, for example, by a polycondensation reaction between a carboxyl group (including an acid halide group) and a hydroxyl group (including an N-methylol group). In the polyamine main chain, repeating units are bonded by an imino bond (—NH—). The polyamine main chain is obtained, for example, by a ring-opening polymerization reaction of an ethyleneimine group. The polyamide main chain has repeating units bonded by an amide bond (—NH—CO—). The polyamide main chain is obtained, for example, by a reaction between an isocyanate group and a carboxyl group (including an acid halide group). The melamine resin main chain is obtained, for example, by a polycondensation reaction between a triazine group (eg, melamine) and an aldehyde (eg, formaldehyde). In the melamine resin, the main chain itself has a crosslinked or polymerized structure.

  For the purpose of controlling the refractive index of the hard coat layer, a high refractive index monomer, inorganic fine particles, or both can be added to the binder of the hard coat layer. In addition to the effect of controlling the refractive index, the inorganic fine particles also have an effect of suppressing curing shrinkage due to a crosslinking reaction. In the present invention, after the hard coat layer is formed, the polyfunctional monomer and / or the polymer formed by polymerizing the high refractive index monomer and the like and the inorganic fine particles dispersed therein are referred to as a binder.

  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.

Examples of the inorganic fine particles include oxides of at least one metal selected from silicon, zirconium, titanium, aluminum, indium, zinc, tin, and antimony, and BaSO ₄ , CaCO ₃ , talc, and kaolin. The particle size is 100 nm or less, preferably 50 nm or less. By miniaturizing the inorganic fine particles to 100 nm or less, a hard coat layer that does not impair the transparency can be formed.
For the purpose of increasing the refractive index of the hard coat layer, the inorganic fine particles are preferably oxide ultrafine particles of at least one metal selected from Al, Zr, Zn, Ti, In and Sn. ZrO ₂ , TiO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and the like. Among these, ZrO ₂ is particularly preferably used.
The addition amount of the high refractive index monomer or inorganic fine particles is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, based on the total mass of the binder. Two or more kinds of inorganic fine particles may be used in the hard coat layer.

The haze value of the hard coat layer is preferably 10% or more, more preferably 20% to 80%, still more preferably 30% to 70%, and most preferably 35% in order to improve the viewing angle characteristics by scattering. ~ 60%.
The antireflection film of the present invention is a film having very little or almost no surface unevenness and almost no surface haze. When haze is imparted, it is preferably provided as an internal haze. Therefore, the hard coat layer has an internal haze, that is, has an internal scattering property. As a result, the haze value of the antireflection film is preferably 10% or more, more preferably 20% to 80%, still more preferably 30%. ~ 70%, most preferably 35% -60%.

In order to provide a viewing angle expansion function, in addition to adjusting the haze value, it is important to adjust the intensity distribution (scattered light profile) of scattered light measured with a goniophotometer of the hard coat layer. . For example, in the case of a liquid crystal display, the viewing angle characteristics are improved as the light emitted from the backlight is diffused by the antireflection film installed on the surface of the polarizing plate on the viewing side. However, if it is diffused too much, backscattering will increase and the front luminance will decrease, or the scattering will be too great and the image clarity will deteriorate. Therefore, it is necessary to control the scattered light intensity distribution of the hard coat layer within a certain range. In order to achieve the desired visual characteristics, the scattered light intensity at an output angle of 30 °, which correlates with the effect of improving the viewing angle in particular, is 0.01% to 0.2% with respect to the light intensity at the output angle of 0 ° of the scattered light profile. %, 0.02% to 0.15% is more preferable, and 0.02% to 0.1% is most preferable.
The scattered light profile can be measured by using an automatic goniophotometer GP-5 manufactured by Murakami Color Research Laboratory Co., Ltd. for an antireflection film provided with a hard coat layer.

As a method of imparting internal scattering properties to the hard coat layer or a method of imparting a desired scattering profile, a light transmitting material having a refractive index different from that of the binder is contained in a binder (including the inorganic particles capable of adjusting the refractive index). It is preferable to contain conductive particles. The refractive index difference between the binder and the translucent particles is preferably 0.02 to 0.20. The difference in refractive index within the above range causes an appropriate light diffusion effect and does not cause the entire film to be whitened due to an excessive light diffusion effect. The refractive index difference is more preferably 0.03 to 0.15, and most preferably 0.04 to 0.13.
The combination of the binder and the translucent particles can be appropriately selected for the purpose of adjusting the refractive index difference.

  The particle diameter of the translucent particles is preferably 0.5 μm to 5 μm. If the particle size is in the above range, the light diffusion effect is moderate, the backscattering is small, the light utilization efficiency is sufficient, the surface irregularities are small, and white blurring and glare phenomenon hardly occur. The particle size of the translucent particles is preferably 0.7 μm to 4.5 μm, and most preferably 1.0 μm to 4.0 μm.

  When the light-transmitting particles are contained in the hard coat layer, it is necessary to adjust the film thickness of the hard coat layer so that surface irregularities due to the particles are not generated. Usually, the surface roughness Ra (centerline average roughness) can be reduced to 0.10 μm or less by increasing the film thickness so that the protrusions of the particles do not protrude from the hard coat surface.

The translucent particles may be organic particles or inorganic particles. As the particle size is not more varied, the scattering characteristics are less varied and the design of the haze value is facilitated. As the translucent fine particles, plastic beads are preferable, and those having high transparency and a difference in refractive index from the binder as described above are preferable.
Organic particles include polymethyl methacrylate beads (refractive index 1.49), acrylic-styrene copolymer beads (refractive index 1.54), melamine beads (refractive index 1.57), polycarbonate beads (refractive index 1.57). ), Styrene beads (refractive index 1.60), cross-linked polystyrene beads (refractive index 1.61), polyvinyl chloride beads (refractive index 1.60), benzoguanamine-melamine formaldehyde beads (refractive index 1.68), etc. It is done.
As the inorganic particles, silica beads (refractive index 1.44), alumina beads (refractive index 1.63), and the like are used.

  As described above, the particle size of the translucent particles may be appropriately selected from 0.5 to 5 μm, and may be used in combination of two or more, and may be used in an amount of 5 to 30 with respect to 100 parts by mass of the binder. It is good to contain a mass part.

  In the case of the above translucent particles, the translucent particles easily settle in the binder, and therefore an inorganic filler such as silica may be added to prevent sedimentation. As the amount of the inorganic filler added increases, it is more effective in preventing the sedimentation of the translucent fine particles, but adversely affects the transparency of the coating film. Therefore, preferably, an inorganic filler having a particle size of 0.5 μm or less is contained in an amount of less than 0.1% by mass so as not to impair the transparency of the coating film with respect to the binder.

<Surfactant for hard coat layer>
The hard coat layer of the present invention is a fluorine-based or silicone-based surfactant in order to improve surface failure such as uneven coating, uneven drying, point defects, etc., and to ensure surface uniformity, or Both of them are preferably contained in the coating composition for forming the light diffusion layer. In particular, a fluorine-based surfactant is preferably used because an effect of improving surface defects such as coating unevenness, drying unevenness, and point defects of the antireflection film of the present invention appears in a smaller addition amount.
The purpose is to increase productivity by giving high-speed coating suitability while improving the surface uniformity.

  Preferable examples of the fluorosurfactant include a fluoroaliphatic group-containing copolymer (sometimes abbreviated as “fluorine polymer”), and the fluoropolymer includes the following monomer (i): An acrylic resin, a methacrylic resin, and a vinyl monomer copolymerizable therewith, characterized by containing a corresponding repeating unit, or containing a repeating unit corresponding to the monomer (ii) below: Copolymers are useful.

(I) Fluoroaliphatic group-containing monomer represented by the following general formula

General formula

In the general formula A, R ¹¹ represents a hydrogen atom or a methyl group, X represents an oxygen atom, a sulfur atom or —N (R ¹² ) —, m is an integer of 1-6, and n is an integer of 2-4. Represent. R ¹² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, specifically a methyl group, an ethyl group, a propyl group or a butyl group, preferably a hydrogen atom or a methyl group. X is preferably an oxygen atom.

(Ii) a monomer represented by the following general formula (b) copolymerizable with (i) above

General formula

In general formula B, R ¹³ represents a hydrogen atom or a methyl group, Y represents an oxygen atom, a sulfur atom or —N (R ¹⁵ ) —, R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, specifically Specifically, it represents a methyl group, an ethyl group, a propyl group, or a butyl group, preferably a hydrogen atom or a methyl group. Y is an oxygen atom, -N (H) -, and -N (CH ₃₎ - it is preferred.
R ¹⁴ represents a linear, branched or cyclic alkyl group having 4 to 20 carbon atoms which may have a substituent. Examples of the substituent for the alkyl group of R ¹⁴ include a hydroxyl group, an alkylcarbonyl group, an arylcarbonyl group, a carboxyl group, an alkyl ether group, an aryl ether group, a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom, a nitro group, and a cyano group. , Amino groups and the like, but not limited thereto. Examples of the linear, branched or cyclic alkyl group having 4 to 20 carbon atoms include a butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and undecyl group which may be linear or branched. , Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, octadecyl group, eicosanyl group, etc., and monocyclic cycloalkyl groups such as cyclohexyl group, cycloheptyl group and bicycloheptyl group, bicyclodecyl group, tricycloundecyl group, A polycyclic cycloalkyl group such as a tetracyclododecyl group, an adamantyl group, a norbornyl group, a tetracyclodecyl group, or the like is preferably used.

  The amount of the fluoroaliphatic group-containing monomer represented by the general formula (a) used in the fluoropolymer used in the present invention is 10 mol% or more based on each monomer of the fluoropolymer, preferably Is 15 to 70 mol%, more preferably in the range of 20 to 60 mol%.

The preferred weight average molecular weight of the fluoropolymer used in the present invention is preferably 3000 to 100,000, more preferably 5,000 to 80,000.
Furthermore, the preferable addition amount of the fluoropolymer used in the present invention is in the range of 0.001 to 5% by mass, preferably in the range of 0.005 to 3% by mass, and more preferably, with respect to the coating solution. It is the range of 0.01-1 mass%. If the addition amount of the fluorine-based polymer is less than 0.001% by mass, the effect is insufficient. Adversely affect the scratch resistance).

  Examples of the specific structure of the fluoropolymer composed of the fluoroaliphatic group-containing monomer represented by the general formula (i) are shown below, but this is not restrictive. In addition, the number in a formula shows the molar ratio of each monomer component. Mw represents a mass average molecular weight.

However, the use of such a fluorine-based polymer reduces the surface energy of the antiglare layer due to segregation of functional groups containing F atoms on the surface of the hard coat layer, resulting in low refraction on the hard coat layer. When the rate layer is overcoated, there arises a problem that the antireflection performance deteriorates. This is presumably because minute unevenness that cannot be visually detected in the low refractive index layer deteriorates because the wettability of the curable composition used for forming the low refractive index layer deteriorates. To solve such problems, by adjusting the structure and amount of the fluorine-based polymer, the surface energy of the hard coat layer preferably in ^{20mN · m -1 ~50mN · m -1} , more preferably it was found that it is effective to control the ^{30mN · m -1 ~40mN · m -1} . In order to realize the surface energy as described above, F / C, which is a ratio of a peak derived from a fluorine atom and a peak derived from a carbon atom, measured by X-ray photoelectron spectroscopy is 0.1 to 1.5. is required.

  Alternatively, by selecting a fluorine-based polymer that is extracted by the solvent that forms the upper layer when the upper layer is applied, it is not unevenly distributed on the lower layer surface (= interface), so that the adhesion between the upper layer and the lower layer is provided. The surface energy of the hard coat layer before application of the low refractive index layer can be reduced by preventing the reduction of surface free energy that can provide an antireflection film having high surface resistance even in high-speed application and having high scratch resistance. The purpose can also be achieved by controlling the range. Examples of such materials include an acrylic resin, a methacrylic resin, and a vinyl monomer copolymerizable therewith, containing a repeating unit corresponding to a fluoroaliphatic group-containing monomer represented by the following general formula C And a copolymer.

(Iii) A fluoroaliphatic group-containing monomer represented by the following general formula C

General formula C

In the general formula C, R ²¹ represents a hydrogen atom, a halogen atom or a methyl group, and more preferably a hydrogen atom or a methyl group. X ² represents an oxygen atom, a sulfur atom or —N (R ²² ) —, more preferably an oxygen atom or —N (R ²² ) —, and still more preferably an oxygen atom. m is an integer from 1 to 6 (more preferably from 1 to 3, more preferably 1), and n is an integer from 1 to 18 (more preferably from 4 to 12, and even more preferably from 6 to 8). Represents. R ²² represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms which may have a substituent, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and further preferably a hydrogen atom or a methyl group. X ² is preferably an oxygen atom.
In addition, two or more kinds of fluoroaliphatic group-containing monomers represented by the general formula C may be contained in the fluorine-based polymer as constituent components.

(Iv) a monomer represented by the following general formula D copolymerizable with the above (iii)

General formula D

In the general formula D, R ²³ represents a hydrogen atom, a halogen atom or a methyl group, more preferably a hydrogen atom or a methyl group. Y ² represents an oxygen atom, a sulfur atom or —N (R ²⁵ ) —, more preferably an oxygen atom or —N (R ²⁵ ) —, and still more preferably an oxygen atom. R ²⁵ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and still more preferably a hydrogen atom or a methyl group.
R ²⁴ is an optionally substituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an alkyl group containing a poly (alkyleneoxy) group, and an optionally substituted aromatic group. (For example, a phenyl group or a naphthyl group). A linear, branched or cyclic alkyl group having 1 to 12 carbon atoms or an aromatic group having 6 to 18 carbon atoms is more preferable, and a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms is more preferable. .

  Hereinafter, examples of specific structures of fluoropolymers containing a repeating unit corresponding to the fluoroaliphatic group-containing monomer represented by formula (c) are shown, but the present invention is not limited thereto. In addition, the number in a formula shows the molar ratio of each monomer component. Mw represents a mass average molecular weight.

  Further, if the reduction of the surface energy is prevented when the low refractive index layer is overcoated on the hard coat layer, the deterioration of the antireflection performance can be prevented. When coating the hard coat layer, the surface tension of the coating solution is lowered by using a fluoropolymer to improve surface uniformity and maintain high productivity by high-speed coating. After coating the hard coat layer, corona treatment, UV treatment, heat treatment, saponification Corona treatment is particularly preferred using surface treatment methods such as treatment and solvent treatment, but the surface energy of the hard coat layer before application of the low refractive index layer is controlled within the above range by preventing the reduction of surface free energy. You can also achieve your goals.

  Moreover, you may add a thixotropic agent in the coating composition for forming the hard-coat layer of this invention. Examples of the thixotropic agent include silica and mica of 0.1 μm or less. In general, the content of these additives is preferably about 1 to 10 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin.

  When the hard coat layer and the transparent support are in contact, the solvent of the coating solution for forming the hard coat layer is used to control the unevenness of the hard coat layer surface (reducing unevenness or flattening) and the transparent support and hard support. In order to achieve both adhesion with the coat layer, it is composed of at least one solvent that dissolves the transparent support (for example, triacetylcellulose support) and at least one solvent that does not dissolve the transparent support. Is preferred. More preferably, at least one of the solvents that do not dissolve the transparent support preferably has a higher boiling point than at least one of the solvents that dissolve the transparent support. More preferably, the difference in boiling point temperature between the solvent having the highest boiling point among the solvents that do not dissolve the transparent support and the solvent having the highest boiling point among the solvents that dissolve the transparent support is 30 ° C. or more, Preferably it is 50 degreeC or more.

As a solvent for dissolving the transparent support (preferably triacetyl cellulose),
Ethers having 3 to 12 carbon atoms: Specifically, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5- Trioxane, tetrahydrofuran, anisole and phenetole, etc.
Ketones having 3 to 12 carbon atoms: specifically, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone,
Esters having 3 to 12 carbon atoms: Specifically, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, propion brewed ethyl, n-pentyl acetate, γ-ptyrolactone, etc. ,
Organic solvent having two or more kinds of functional groups: Specifically, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-methoxyethanol, 2-propoxyethanol 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, and ethyl acetoacetate.
These can be used alone or in combination of two or more. The solvent for dissolving the transparent support is preferably a ketone solvent.

As a solvent that does not dissolve the transparent support (preferably triacetylcellulose), methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2 -Butanol, cyclohexanol, isobutyl acetate, methyl isobutyl ketone, 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-pentanone, 3-heptanone, 4-heptanone.
These can be used alone or in combination of two or more.

  The mass ratio (A / B) of the total amount (A) of the solvent that dissolves the transparent support and the total amount (B) of the solvent that does not dissolve the transparent support is preferably 5/95 to 50/50, more preferably 10 / It is 90-40 / 60, More preferably, it is 15 / 85-30 / 70.

(Low refractive index layer)
The antireflection film of the present invention has a low refractive index layer as the outermost layer. The refractive index of the low refractive index layer is preferably 1.20 to 1.46, more preferably 1.25 to 1.41, and most preferably 1.30 to 1.39. Further, the low refractive index layer preferably satisfies the following formula (1) from the viewpoint of reducing the reflectance.

Formula (1): (m ₁ /4)λ×0.7<n ₁ d ₁ <(m ₁ /4)λ×1.3

In the above formula (1), m ₁ is a positive odd number, n ₁ is the refractive index of the low refractive index layer, and d ₁ is the film thickness (nm) of the low refractive index layer. Further, λ is a wavelength, which is a value in the range of 500 to 550 nm. Note that satisfies the above equation (1), it means that m ₁ satisfying the formula (1) in the above range wavelengths (positive odd number, usually 1) is present.

  In the low refractive index layer, a binder is used for dispersing and fixing the hollow silica particles of the present invention. As the binder, the binder described in the hard coat layer can be used, but it is preferable to use a fluorine-containing polymer having a low refractive index or a fluorine-containing sol-gel material. The fluorine-containing polymer or fluorine-containing sol-gel is a material that has a dynamic friction coefficient of 0.03 to 0.15 on the surface of the low refractive index layer formed by crosslinking with heat or ionizing radiation and a contact angle of 90 to 120 ° with water. Is preferred.

[Fluoropolymer]
Examples of the fluorine-containing polymer used in the low refractive index layer include hydrolysis and dehydration condensate of perfluoroalkyl group-containing silane compounds (for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane). And a fluorine-containing copolymer having a fluorine-containing monomer unit and a structural unit for imparting crosslinking reactivity as structural components.

  Specific examples of the fluorine-containing monomer unit include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.), (meta ) A part of acrylic acid or a fully fluorinated alkyl ester derivative (for example, Biscoat 6FM (manufactured by Osaka Organic Chemical) or M-2020 (manufactured by Daikin)), a complete or partially fluorinated vinyl ether, and the like. From the viewpoint of refractive index, solubility, transparency, availability, etc., hexafluoropropylene is particularly preferable.

Examples of the structural unit for imparting crosslinking reactivity include units represented by the following (A), (B), and (C).
(A): a structural unit obtained by polymerization of a monomer having a self-crosslinkable functional group in the molecule in advance such as glycidyl (meth) acrylate or glycidyl vinyl ether,
(B): Monomer having a carboxyl group, hydroxy group, amino group, sulfo group, etc. (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether) , Maleic acid, crotonic acid, etc.)
(C): A group having a crosslinkable functional group separately from a group that reacts with the functional groups (A) and (B) in the molecule and a structural unit of the above (A) and (B). Examples of the structural unit to be obtained include (for example, a structural unit that can be synthesized by a technique such as allowing acrylic acid chloride to act on a hydroxyl group).

  In the constitutional unit (C), particularly in the present invention, the crosslinkable functional group is preferably a photopolymerizable group. Here, examples of the photopolymerizable group include (meth) acryloyl group, alkenyl group, cinnamoyl group, cinnamylideneacetyl group, benzalacetophenone group, styrylpyridine group, α-phenylmaleimide group, phenylazide group, sulfonylazide. Group, carbonyl azide group, diazo group, o-quinonediazide group, furylacryloyl group, coumarin group, pyrone group, anthracene group, benzophenone group, stilbene group, dithiocarbamate group, xanthate group, 1,2,3-thiadiazole group, cyclo A propene group, an azadioxabicyclo group, etc. can be mentioned, These may be not only 1 type but 2 or more types. Of these, a (meth) acryloyl group and a cinnamoyl group are preferable, and a (meth) acryloyl group is particularly preferable.

Specific methods for preparing the photopolymerizable group-containing copolymer include, but are not limited to, the following methods.
(1) A method of esterifying a crosslinkable functional group-containing copolymer containing a hydroxyl group by reacting (meth) acrylic acid chloride,
(2) A method of urethanizing a crosslinkable functional group-containing copolymer containing a hydroxyl group by reacting an isocyanate group-containing (meth) acrylic ester,
(3) A method of esterifying by reacting (meth) acrylic acid with a crosslinkable functional group-containing copolymer containing an epoxy group,
(4) A method in which a crosslinkable functional group-containing copolymer containing a carboxyl group is esterified by reacting a containing (meth) acrylic acid ester containing an epoxy group.
The amount of the photopolymerizable group introduced can be arbitrarily adjusted. From the viewpoints of surface stability of the coating film, reduction of surface failure when coexisting with inorganic fine particles, and improvement of film strength, carboxyl groups, hydroxyl groups, etc. It is also preferable to leave a certain amount.

  In addition to the above-mentioned fluorine-containing monomer units and structural units for imparting crosslinking reactivity, monomers not containing fluorine atoms can be copolymerized as appropriate from the viewpoints of solubility in solvents and film transparency. There are no particular limitations on the monomer units that can be used in combination, such as olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate), Methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyltoluene, α-methylstyrene, etc.), vinyl ethers (methyl vinyl ether, ethyl vinyl ether) , Cyclohexyl vinyl ether, etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tertbutylacrylamide, N-cyclohexyl acrylic) Amides), methacrylamides, and acrylonitrile derivatives.

  The fluorine-containing polymer particularly useful in the present invention is a random copolymer of perfluoroolefin and vinyl ethers or vinyl esters. In particular, it preferably has a group capable of undergoing a crosslinking reaction alone (a radical reactive group such as a (meth) acryloyl group, a ring-opening polymerizable group such as an epoxy group or an oxetanyl group). These crosslinkable group-containing polymerized units preferably occupy 5 to 70 mol% of the total polymerized units of the polymer, particularly preferably 30 to 60 mol%. Regarding preferred polymers, JP-A-2002-243907, JP-A-2002-372601, JP-A-2003-26732, JP-A-2003-222702, JP-A-2003-294911, JP-A-2003-329804, JP-A-2004. -4444 and JP, 2004-45462, A can be mentioned.

  In addition, a polysiloxane structure is preferably introduced into the fluorine-containing polymer of the present invention for the purpose of imparting antifouling properties. There is no limitation on the method for introducing the polysiloxane structure, but for example, as described in JP-A-11-189621, JP-A-11-228631, and JP-A-2000-313709, a polysiloxane block using a silicone macroazo initiator is used. A method of introducing a copolymer component and a method of introducing a polysiloxane graft copolymer component using a silicone macromer as described in JP-A-2-251555 and JP-A-2-308806 are preferred. These polysiloxane components are preferably 0.5 to 10% by mass, particularly preferably 1 to 5% by mass in the polymer.

  In addition to the above, reactive group-containing polysiloxanes (for example, KF-100T, X-22-169AS, KF-102, X-22-3701IE, X-22-164B, X-22- 5002, X-22-173B, X-22-174D, X-22-167B, X-22-161AS (above trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), AK-5, AK-30, AK-32 (above A product name, manufactured by Toa Gosei Co., Ltd.), Silaplane FM0275, Silaplane FM0721 (manufactured by Chisso), etc.) is also preferred. In this case, these polysiloxanes are preferably added in the range of 0.5 to 10% by mass of the total solid content of the low refractive index layer, and particularly preferably 1 to 5% by mass.

  The preferred molecular weight of the polymer that can be preferably used in the present invention is a mass average molecular weight of 5,000 or more, preferably 10,000 to 500,000, most preferably 15,000 to 200,000. By using polymers having different average molecular weights in combination, it is possible to improve the coating surface condition and scratch resistance.

  As described in JP-A-10-25388 and JP-A-10-147739, a curing agent may be suitably used in combination with the above polymer. A combination with a compound having a fluorine-containing polyfunctional polymerizable unsaturated group as described in JP-A-2000-17028 and JP-A-2002-145952 is also preferred. Preferable examples include the polyfunctional monomers described in the hard coat layer.

[Fluorine-containing silane compounds]
In the low refractive index layer using the hollow silica of the present invention, a hydrolyzate of an organosilane compound and / or a condensate thereof having a high affinity with silica can be used as a binder. Specific examples of the binder include those described in JP-A No. 2002-79616, JP-A No. 2002-265866, JP-A No. 2002-317152, and the like. From the viewpoint of antifouling properties, it is also preferable to provide an antifouling layer as described in JP-A-2002-277604.

[Hollow silica fine particles]
In the low refractive index layer of the present invention, hollow silica fine particles are contained for the purpose of achieving both low refractive index and scratch resistance.
The refractive index of the hollow silica fine particles is preferably 1.15 to 1.40, more preferably 1.17 to 1.35, and most preferably 1.17 to 1.30. The refractive index here represents the refractive index of the whole particle, and does not represent the refractive index of only the outer shell silica forming the hollow silica fine particles. At this time, when the radius of the cavity in the particle is a and the radius of the particle outer shell is b, the porosity x is calculated by the following formula (VIII).
(Formula VIII)
^{x = (4πa 3/3)} / (4πb 3/3) × 100
The porosity x is preferably 10 to 60%, more preferably 20 to 60%, and most preferably 30 to 60%. If hollow silica fine particles are made to have a lower refractive index and a higher porosity, the thickness of the outer shell becomes thinner and the strength of the particles becomes weaker. Rate particles are not preferred.
A method for producing hollow silica fine particles is described in, for example, Japanese Patent Application Laid-Open Nos. 2001-233611 and 2002-79616. In particular, particles having cavities inside the shell and having fine pores in the shell are particularly preferred. The refractive index of these hollow silica particles can be calculated by the method described in JP-A-2002-79616.

The coating amount of the hollow silica fine particles is preferably ^{1mg / m 2 ~100mg / m 2} , more preferably ^{5mg / m 2 ~80mg / m 2} , more preferably from ^{10mg / m 2 ~60mg / m 2} . When the coating amount is in the above range, the effect of lowering the refractive index and the effect of improving the scratch resistance are exhibited, and fine irregularities are not generated on the surface of the low refractive index layer. There is no worry that the reflectance will deteriorate.
The average particle size of the hollow silica fine particles is 5 nm to 200 nm, preferably 20 nm to 150 nm, more preferably 30 nm to 80 nm, and still more preferably 40 nm to 65 nm.
If the particle size of the hollow silica fine particles is within the above range, the ratio of the cavity portion is moderate, the refractive index is lowered, and the appearance such as black tightening based on fine irregularities on the surface of the low refractive index layer is deteriorated, and the integrated reflectance is deteriorated. There is no.

The silica in the outer shell part of the hollow silica fine particles may be either crystalline or amorphous. The size distribution of the hollow silica fine particles is preferably monodispersed particles, but may be polydispersed particles or aggregated particles as long as a predetermined particle size is satisfied. The shape is most preferably spherical, but there is no problem even if it is indefinite.
Moreover, two or more types of hollow silica having different particle average particle sizes can be used in combination.
Here, the average particle diameter of the hollow silica fine particles can be determined from an electron micrograph.
The specific surface area of the hollow silica in the present invention is preferably from 20 to 300 m ² / g, more preferably 30~120m ² / g, most preferably 40~90m ² / g. The surface area can be determined by the BET method using nitrogen.

In the present invention, for the purpose of improving the scratch resistance, other inorganic fillers can be contained in combination with the hollow silica fine particles.
Since the inorganic filler is contained in the low refractive index layer, it is desirable that the inorganic filler has a low refractive index. Examples include magnesium fluoride and silica. In particular, silica fine particles having no voids are preferable in terms of refractive index, dispersion stability, and cost. The preferred particle size of the silica fine particles without voids is 30 nm to 150 nm, more preferably 35 nm to 80 nm, and most preferably 40 nm to 60 nm.
Further, at least one kind of silica fine particles having an average particle size of less than 25% of the thickness of the low refractive index layer (referred to as “small size particle size silica particles”) is used as silica fine particles having the above particle size (“large size particles”). It is preferably used in combination with “silica fine particles having a diameter”.
Since the fine silica particles having a small size can be present in the gaps between the fine silica particles having a large size, the fine particles can contribute as a retaining agent for the fine silica particles having a large size.
The average particle diameter of the silica fine particles having a small size is preferably 1 nm to 20 nm, more preferably 5 nm to 15 nm, and particularly preferably 10 nm to 15 nm. Use of such silica fine particles is preferable in terms of raw material costs and a retaining agent effect.

  Silica fine particles are treated by physical surface treatment such as plasma discharge treatment or corona discharge treatment in order to stabilize dispersion in the dispersion or coating solution, or to improve the affinity and binding to the binder component. Chemical surface treatment with a surfactant, a coupling agent, or the like may be performed. The use of a coupling agent is particularly preferred. As the coupling agent, an alkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. Of these, silane coupling agents are preferred, organosilane compounds represented by general formulas (2) and (3) described later are preferred, and treatment with a silane coupling agent having an acryloyl group or a methacryloyl group is particularly effective.

The above coupling agent may be used as a surface treatment agent for the inorganic filler of the low refractive index layer in advance for surface treatment prior to the preparation of the layer coating solution. It is preferably contained in the layer.
The silica fine particles are preferably dispersed in the medium in advance before the surface treatment in order to reduce the load of the surface treatment. Specific examples of the surface treatment agent and the catalyst that can be preferably used in the present invention include organosilane compounds and catalysts described in WO 2004/017105.

  In the present invention, at least one of the hard coat layer and the low refractive index layer contains at least one of a hydrolyzate of an organosilane compound and a partial condensate thereof, a so-called sol component (hereinafter referred to as this). It is preferable from the viewpoint of scratch resistance, and it is more preferable to contain it in both the hard coat layer and the low refractive index layer.

  The organosilane compound used can be represented by the following general formula (2).

Formula _{^{(2) :( R 10) m}} -Si (X) 4-m

In the general formula (2), R ¹⁰ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.
X represents a hydrolyzable group, for example, an alkoxy group (preferably an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group or an ethoxy group), halogen (for example, Cl, Br, I, etc.), or R ² COO (R ² is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, such as CH ₃ COO, C ₂ H ₅ COO, etc.), preferably an alkoxy group, particularly preferably methoxy. Group or 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 may be different even in the same, respectively. m is preferably 1 or 2, particularly preferably 1.

The substituent contained in R ¹⁰ is not particularly limited, but is halogen (fluorine, chlorine, bromine, etc.), hydroxyl group, mercapto group, carboxyl group, epoxy group, alkyl group (methyl, ethyl, i-propyl, propyl, t -Butyl etc.), aryl groups (phenyl, naphthyl etc.), aromatic heterocyclic groups (furyl, pyrazolyl, pyridyl etc.), alkoxy groups (methoxy, ethoxy, i-propoxy, hexyloxy etc.), aryloxy (phenoxy etc.) , Alkylthio groups (such as methylthio, ethylthio), arylthio groups (such as phenylthio), alkenyl groups (such as vinyl and 1-propenyl), acyloxy groups (such as acetoxy, acryloyloxy, methacryloyloxy), alkoxycarbonyl groups (methoxycarbonyl, ethoxycarbonyl) Etc.), aryloxyca Bonyl group (phenoxycarbonyl etc.), carbamoyl group (carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-methyl-N-octylcarbamoyl etc.), acylamino group (acetylamino, benzoylamino, acrylicamino, methacrylamino) Etc.), and these substituents may be further substituted.

When there are a plurality of R ^{10 s} , at least one of them is preferably a substituted alkyl group or a substituted aryl group.

Among the organosilane compounds represented by the general formula (2), an organosilane compound having a vinyl polymerizable substituent represented by the following general formula (3) is preferable.
General formula (3)

In the general formula (3), R ¹ represents a hydrogen atom, an alkyl group (such as a methyl group or an ethyl group), an alkoxy group (such as a methoxy group or an ethoxy group), an alkoxycarbonyl group (such as a methoxycarbonyl group or an ethoxycarbonyl group), cyano A group, a halogen atom (fluorine atom, chlorine atom, etc.); Among these, a hydrogen atom, a methyl group, a methoxy group, a methoxycarbonyl group, a cyano group, a fluorine atom, and a chlorine atom are preferable, a hydrogen atom, a methyl group, a methoxycarbonyl group, a fluorine atom, and a chlorine atom are more preferable, and a hydrogen 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. Of these, a single bond, an ester group, and an amide group are preferable, a single bond and an ester group are more preferable, and an ester group is particularly preferable.

  L represents a divalent linking group. Specifically, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group having a linking group (for example, ether, ester, amide, etc.) inside, and a linking group inside. And a substituted or unsubstituted arylene group. Of these, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, and an alkylene group having a linking group therein are preferred, and an unsubstituted alkylene group, an unsubstituted arylene group, and an ether or ester inside. An alkylene group having a linking group is more preferred, and an unsubstituted alkylene group and an alkylene group having a linking group consisting of an ether or ester 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 a plurality of X are present, the plurality of X may be the same or different. n is preferably 0.
R ¹⁰ has the same meaning as in formula (2), 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 in formula (2), preferably a halogen, a hydroxyl group, and an unsubstituted alkoxy group, more preferably a chlorine atom, a hydroxyl group, and an unsubstituted alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, and An alkoxy group having 1 to 3 carbon atoms is more preferable, and a methoxy group is particularly preferable.

  As the organosilane compound, two or more compounds represented by the general formula (2) and the general formula (3) may be used in combination. Specific examples of the compounds represented by general formula (2) and general formula (3) are shown below, but the present invention is not limited thereto.

  The organosilane hydrolysis / condensation reaction can be carried out in the absence of a solvent or in a solvent, but an organic solvent is preferably used in order to mix the components uniformly. For example, alcohols, aromatic hydrocarbons, ethers, Ketones and esters are preferred.

  The solvent is preferably one that dissolves the organosilane and the catalyst. In addition, it is preferable in the process to use an organic solvent as a coating liquid or a part of the coating liquid, and those that do not impair the solubility or dispersibility when mixed with other materials such as a fluorine-containing polymer are preferable.

  Among these, examples of the alcohols include monohydric alcohols and dihydric alcohols. Among these, monohydric alcohols are preferably saturated aliphatic alcohols having 1 to 8 carbon atoms. Specific examples of these alcohols include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol. Examples thereof include monobutyl ether and ethylene glycol monoethyl ether acetate.

Specific examples of aromatic hydrocarbons include benzene, toluene, xylene and the like. Specific examples of ethers include tetrahydrofuran and dioxane. Specific examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, Specific examples of esters such as diisobutyl ketone include ethyl acetate, propyl acetate, butyl acetate, and propylene carbonate.
These organic solvents can be used alone or in combination of two or more.
The concentration of the solid content in the reaction is not particularly limited, but is usually in the range of 1% to 90%, preferably in the range of 20% to 70%.

  The hydrolysis / condensation reaction of organosilane 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, Organic bases such as pyridine; metal alkoxides such as triisopropoxyaluminum and tetrabutoxyzirconium; metal chelate compounds, and the like. From the viewpoint of production stability of the sol solution and storage stability of the sol solution, an acid catalyst ( Inorganic acids, organic acids) and metal chelate compounds are preferred. As an acid catalyst, an acid dissociation constant in water (pKa value (25 ° C.)) of 4.5 or less is preferable for inorganic acids such as hydrochloric acid and sulfuric acid, and an organic acid, and acid dissociation constant in hydrochloric acid, sulfuric acid and water. Is more preferably an organic acid having an acid dissociation constant of 2.5 or less in hydrochloric acid, sulfuric acid or water, and an organic acid having an acid dissociation constant in water of 2.5 or less is further preferred. Preferably, methanesulfonic acid, oxalic acid, phthalic acid, and malonic acid are more preferable, and oxalic acid is particularly preferable.

The hydrolysis / condensation reaction is usually performed by adding 0.3 to 2 mol, preferably 0.5 to 1 mol of water to 1 mol of the hydrolyzable group of organosilane, and in the presence or absence of the solvent. Under stirring and preferably in the presence of a catalyst at 25-100 ° C.
When the hydrolyzable group is an alkoxide and the catalyst is an organic acid, the carboxyl group or sulfo group of the organic acid supplies protons, so the amount of water added can be reduced, and the amount of the alkoxide group of the organosilane can be reduced to 1 mol. The amount of water added 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. When alcohol is used as the solvent, it is also preferred that substantially no water is added.

The catalyst is used in an amount of 0.01 to 10 mol%, preferably 0.1 to 5 mol% based on the hydrolyzable group when the catalyst is an inorganic acid, and when the catalyst is an organic acid, The optimum amount used varies depending on the amount of water added, but in the case of adding water, it is 0.01 to 10 mol%, preferably 0.1 to 5 mol% with respect to the hydrolyzable group. When water is not added, it is 1 to 500 mol%, preferably 10 to 200 mol%, more preferably 20 to 200 mol%, still more preferably 50 to 150 mol%, based on the hydrolyzable group. And particularly preferably 50 to 120 mol%.
Although the reaction is carried out by stirring at 25 to 100 ° C., it is preferably adjusted as appropriate depending on the reactivity of the organosilane.

The metal chelate compound includes an alcohol represented by the general formula R ³ OH (wherein R ³ represents an alkyl group having 1 to 10 carbon atoms) and R ⁴ COCH ₂ COR ⁵ (wherein R ⁴ is 1 carbon atom). -10 alkyl group, R ⁵ is an alkyl group having 1 to 10 carbon atoms or a compound represented by an alkoxy group having 1 to 10 carbon atoms), and is selected from Zr, Ti, and Al. Any metal having a metal as a central metal can be suitably used without particular limitation. Within this category, two or more metal chelate compounds may be used in combination. The metal chelate compound used in the present invention has the general formula Zr (OR ³ ) _p1 (R ⁴ COCHCOR ⁵ ) _p2 , Ti (OR ³ ) _q1 (R ⁴ COCHCOR ⁵ ) _q2 , and Al (OR ³ ) _r1 (R ⁴ Those selected from the group of compounds represented by COCHCOR ⁵ ) _r2 are preferred and serve to promote the condensation reaction of the hydrolyzate and / or partial condensate of the organosilane compound.
R ³ and R ⁴ in the metal chelate compound may be the same or different and each is an alkyl group having 1 to 10 carbon atoms, specifically an ethyl group, n-propyl group, i-propyl group, n-butyl group, sec -Butyl group, t-butyl group, n-pentyl group, phenyl group and the like. R ⁵ represents an alkyl group having 1 to 10 carbon atoms as described above, or an alkoxy group having 1 to 10 carbon atoms such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, and n-butoxy. Group, sec-butoxy group, t-butoxy group and the like. Moreover, p1, p2, q1, q2, r1, and r2 in the metal chelate compound represent integers determined so as to be p1 + p2 = 4, q1 + q2 = 4, and r1 + r2 = 3, respectively.

Specific examples of these metal chelate compounds include tri-n-butoxyethylacetoacetate zirconium, di-n-butoxybis (ethylacetoacetate) zirconium, n-butoxytris (ethylacetoacetate) zirconium, tetrakis (n-propylacetate). Zirconium chelate compounds such as acetate) zirconium, tetrakis (acetylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium; diisopropoxy bis (ethylacetoacetate) titanium, diisopropoxy bis (acetylacetate) titanium, diiso Titanium chelate compounds such as propoxy bis (acetylacetone) titanium; diisopropoxyethyl acetoacetate aluminum, diisopropyl Poxyacetylacetonate aluminum, isopropoxybis (ethylacetoacetate) aluminum, isopropoxybis (acetylacetonate) aluminum, tris (ethylacetoacetate) aluminum, tris (acetylacetonate) aluminum, monoacetylacetonate bis (ethyl) An aluminum chelate compound such as 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.

  The metal chelate compound of the present invention is preferably 0.01 to 50% by mass, more preferably 0.1 to 50%, based on the organosilane, from the viewpoint of the speed of the condensation reaction and the film strength when formed into a coating film. It is used at a ratio of 0.5% by mass, more preferably 0.5-10% by mass.

  The appropriate content of the organosilane sol differs depending on the layer to be added, but the addition amount to the low refractive index layer is preferably 0.1 to 50% by mass of the total solid content of the low refractive index layer, 0.5 -20 mass% is more preferable, and 1-10 mass% is especially preferable. The amount added to the layers other than the low refractive index layer is preferably 0.001 to 50 mass%, more preferably 0.01 to 20 mass%, and more preferably 0.05 to 10 mass% of the total solid content of the containing layer (addition layer). More preferably, it is 0.1 to 5% by mass.

  In the low refractive index layer, the amount of the organosilane sol used relative to the fluorine-containing polymer is 5 to 100% by mass from the viewpoint of the effect of using the sol, the refractive index of the layer, and the shape / planar shape of the layer to be formed. Is preferable, 5-40 mass% is more preferable, 8-35 mass% is still more preferable, and 10-30 mass% is especially preferable.

  The solvent composition of the coating solution used for forming the low refractive index layer according to the present invention may be either single or mixed, and when mixed, the solvent having a boiling point of 100 ° C. or lower is 50 to 100%. Is preferable, more preferably 80 to 100%, more preferably 90 to 100%, and still more preferably 100%. When the solvent having a boiling point of 100 ° C. or lower is in the above range, the drying speed is fast, the coated surface is good, and the coated film thickness is uniform, so that the optical characteristics such as reflectance are also good.

  Examples of the solvent having a boiling point of 100 ° C. or lower include hexane (boiling point 68.7 ° C., hereinafter “° C.” is omitted), heptane (98.4), cyclohexane (80.7), benzene (80.1), and the like. Hydrocarbons such as dichloromethane (39.8), chloroform (61.2), carbon tetrachloride (76.8), 1,2-dichloroethane (83.5), trichloroethylene (87.2), etc. Hydrogens, diethyl ether (34.6), diisopropyl ether (68.5), dipropyl ether (90.5), ethers such as tetrahydrofuran (66), ethyl formate (54.2), methyl acetate (57. 8), esters such as ethyl acetate (77.1) and isopropyl acetate (89), acetone (56.1), 2-butanone (= methyl ethyl ketone, 9.6), alcohols such as methanol (64.5), ethanol (78.3), 2-propanol (82.4), 1-propanol (97.2), acetonitrile (81.6) ), Cyano compounds such as propionitrile (97.4), carbon disulfide (46.2), and the like. Of these, ketones and esters are preferable, and ketones are particularly preferable. Among the ketones, 2-butanone is particularly preferable.

  Examples of the solvent having a boiling point of 100 ° C. or higher include, for example, octane (125.7), toluene (110.6), xylene (138), tetrachloroethylene (121.2), chlorobenzene (131.7), dioxane (101.3). ), Dibutyl ether (142.4), isobutyl acetate (118), cyclohexanone (155.7), 2-methyl-4-pentanone (= MIBK, 115.9), 1-butanol (117.7), N, N-dimethylformamide (153), N, N-dimethylacetamide (166), dimethyl sulfoxide (189), and the like. Cyclohexanone and 2-methyl-4-pentanone are preferable.

  A coating solution for a low refractive index layer is prepared by diluting the low refractive index layer component with the solvent having the above-mentioned composition. The concentration of the coating solution is preferably adjusted as appropriate in consideration of the viscosity of the coating solution and the specific gravity of the layer material, but is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass.

(High refractive index layer)
The antireflection film of the present invention can be provided with a high refractive index layer and a medium refractive index layer on the hard coat layer to enhance the antireflection property. The refractive index of the high refractive index layer and the middle refractive index layer of the present invention is preferably 1.55 to 2.40. In the following specification, the high refractive index layer and the medium refractive index layer may be collectively referred to as a high refractive index layer. In the present invention, “high”, “medium”, and “low” in the high refractive index layer, the medium refractive index layer, and the low refractive index layer represent the relative refractive index relationship between the layers. In terms of the relationship with the transparent support, the refractive index preferably satisfies the relationship of transparent support> low refractive index layer, high refractive index layer> transparent support.

The high refractive index layer of the present invention preferably contains inorganic fine particles mainly composed of titanium dioxide containing at least one element selected from cobalt, aluminum, and zirconium. The main component means a component having the largest content (mass%) among the components constituting the particles.
The inorganic fine particles mainly composed of titanium dioxide in the present invention preferably have a refractive index of 1.90 to 2.80, more preferably 2.10 to 2.80, and 2.20 to 2.80. 80 is most preferred.
The mass average diameter of primary particles of inorganic fine particles mainly composed of titanium dioxide is preferably 1 to 200 nm, more preferably 1 to 150 nm, still more preferably 1 to 100 nm, and particularly preferably 1 to 80 nm.

The particle diameter of the inorganic fine particles can be measured by a light scattering method or an electron micrograph. The specific surface area of the inorganic fine particles is preferably 10 to 400 m ² / g, more preferably from 20 to 200 m ² / g, and most preferably from 30 to 150 m ² / g.
The crystal structure of the inorganic fine particles containing titanium dioxide as a main component is preferably a rutile, rutile / anatase mixed crystal, anatase or amorphous structure, particularly preferably a rutile structure. The main component means a component having the largest content (mass%) among the components constituting the particles.

By containing at least one element selected from Co (cobalt), Al (aluminum) and Zr (zirconium) in the inorganic fine particles mainly composed of titanium dioxide, the photocatalytic activity of titanium dioxide can be suppressed, The weather resistance of the high refractive index layer of the present invention can be improved.
A particularly preferable element is Co (cobalt). It is also preferable to use two or more types in combination.
The content of Co (cobalt), Al (aluminum) or Zr (zirconium) with respect to Ti (titanium) is preferably 0.05 to 30% by mass, more preferably 0.1 to 10% with respect to Ti. % By mass, more preferably 0.2-7% by mass, particularly preferably 0.3-5% by mass, most preferably 0.5-3% by mass.

Co (cobalt), Al (aluminum), and Zr (zirconium) can be present in at least one of the inside and the surface of the inorganic fine particles mainly composed of titanium dioxide, but the inorganic fine particles mainly composed of titanium dioxide. It is preferable to exist in the inside of the inside, and it is most preferable to exist in both the inside and the surface.
There are various methods for causing Co (cobalt), Al (aluminum), and Zr (zirconium) to be present (for example, doped) in the inorganic fine particles mainly composed of titanium dioxide. For example, ion implantation (Vol.18, No.5, pp.262-268, 1998; Yasushi Aoki), published patent publications JP-A-11-263620, JP-A-11-512336, published in Europe. Examples thereof include those described in Japanese Patent No. 0335773 and JP-A-5-330825.
Techniques for introducing Co (cobalt), Al (aluminum), and Zr (zirconium) in the process of forming inorganic fine particles containing titanium dioxide as a main component (for example, Japanese Patent Publication No. 11-512336, European Patent No. 0335773) No. 5, described in JP-A-5-330825) is particularly preferable.

  Co (cobalt), Al (aluminum), and Zr (zirconium) are also preferably present as oxides.

  The inorganic fine particles containing titanium dioxide as the main component can further contain other elements depending on the purpose. Other elements may be included as impurities. Examples of other elements include Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Mg, Si, P, and S.

The inorganic fine particles mainly composed of titanium dioxide used in the present invention may be surface-treated. The surface treatment is performed using an inorganic compound or an organic compound. Examples of inorganic compounds used for the surface treatment include inorganic compounds containing cobalt (CoO ₂ , Co ₂ O ₃ , Co ₃ O _4, etc.), inorganic compounds containing aluminum (Al ₂ O ₃ , Al (OH) _{3, etc.} Etc.), inorganic compounds containing zirconium (ZrO ₂ , Zr (OH) ₄ etc.), inorganic compounds containing silicon (SiO ₂ etc.), inorganic compounds containing iron (Fe ₂ O ₃ etc.), etc. .
Inorganic compounds containing cobalt, inorganic compounds containing aluminum, and inorganic compounds containing zirconium are particularly preferred, and inorganic compounds containing cobalt, Al (OH) ₃ , and Zr (OH) ₄ are most preferred.
Examples of the organic compound used for the surface treatment include a silane coupling agent and a titanate coupling agent. Of these, a silane coupling agent is most preferable, and examples thereof include a silane coupling agent represented by the general formula (2) or the general formula (3).

  The content of the silane coupling agent is preferably 1 to 90% by mass, more preferably 2 to 80% by mass, and particularly preferably 5 to 50% by mass of the total solid content of the high refractive index layer.

  Examples of titanate coupling agents include metal alkoxides such as tetramethoxy titanium, tetraethoxy titanium, and throat tetraisopropoxy titanium, preneact (KR-TTS, KR-46B, KR-55, KR-41B, etc .; Ajinomoto Co., Inc. ))).

Examples of other organic compounds used for the surface treatment include polyols, alkanolamines, and other organic compounds having an anionic group, and particularly preferable are organic compounds having a carboxyl group, a sulfonic acid group, or a phosphoric acid group. A compound.
Stearic acid, lauric acid, oleic acid, linoleic acid, linolenic acid and the like can be preferably used.
The organic compound used for the surface treatment preferably further has a crosslinked or polymerizable functional group. Crosslinkable or polymerizable functional groups include ethylenically unsaturated groups (for example, (meth) acrylic groups, allyl groups, styryl groups, vinyloxy groups, etc.) that can undergo addition reactions and polymerization reactions with radical species, cationic polymerizable groups (Epoxy groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups) and the like can be mentioned, and groups having an ethylenically unsaturated group are preferred.

Two or more kinds of these surface treatments can be used in combination. It is particularly preferable to use an inorganic compound containing aluminum and an inorganic compound containing zirconium in combination.
The inorganic fine particles mainly composed of titanium dioxide of the present invention may have a core / shell structure by surface treatment as described in JP-A No. 2001-166104.

  The shape of the inorganic fine particles mainly composed of titanium dioxide contained in the high refractive index layer is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape or an indefinite shape, and particularly preferably an indefinite shape or a spindle shape. is there.

(Dispersant)
A dispersant can be used to disperse the inorganic fine particles mainly composed of titanium dioxide used in the high refractive index layer of the present invention.
In order to disperse the inorganic fine particles mainly composed of titanium dioxide of the present invention, it is particularly 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 (and a sulfo group), a phosphoric acid group (and a phosphono group), or a sulfonamide group, or a salt thereof is effective. A sulfonic acid group, a phosphoric acid group and a salt thereof are preferable, and a carboxyl group and a phosphoric acid group are particularly preferable. The number of anionic groups contained in the dispersant per molecule may be one or more.
A plurality of anionic groups may be contained for the purpose of further improving the dispersibility of the inorganic fine particles. 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 preferably further contains a crosslinkable 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 (epoxies). 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.

A preferred dispersant used for dispersion of inorganic fine particles mainly composed of titanium dioxide used in the high refractive index layer of the present invention has an anionic group and a crosslinkable or polymerizable functional group, and the crosslinkable or polymerizable functional group. In the side chain.
The weight average molecular weight (Mw) of the dispersant having an anionic group and a crosslinkable or polymerizable functional group and having the crosslinkable or polymerizable functional group in the side chain is not particularly limited, but is preferably 1000 or more. . The more preferable mass average molecular weight (Mw) of the dispersant is 2000 to 1000000, more preferably 5000 to 200000, and particularly preferably 10000 to 100000.

  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. The average number of anionic groups contained in the dispersant per molecule 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 having an anionic group and a crosslinkable or polymerizable functional group and having the crosslinkable or polymerizable functional group in the side chain has the anionic group in the side chain or terminal. Examples of the method for introducing an anionic group into the side chain include an anionic group-containing monomer (for example, (meth) acrylic acid, maleic acid, partially esterified maleic acid, itaconic acid, crotonic acid, 2-carboxyethyl (meth) acrylate. , Polymer reaction such as a method of polymerizing 2-sulfoethyl (meth) acrylate, mono-2- (meth) acryloyloxyethyl ester of phosphoric acid, a method of allowing an acid anhydride to act on a polymer having a hydroxyl group, an amino group, etc. Can be synthesized by using

In the dispersant having an anionic group in the side chain, the composition of the anionic group-containing repeating unit is in the range of 10 ^{−4 to} 100 mol%, preferably 1 to 50 mol%, particularly preferably 5 among all repeating units. ˜20 mol%.
On the other hand, as a technique for introducing an anionic group at the terminal, a technique for carrying out a polymerization reaction in the presence of an anionic group-containing chain transfer agent (for example, thioglycolic acid), an anionic group-containing polymerization initiator (for example, Wako Pure Chemical Industries, Ltd.) It can be synthesized by a technique of conducting a polymerization reaction using industrial V-501).
Particularly preferred dispersants are those having an anionic group in the side chain.

  Examples of the cross-linkable or polymerizable functional group include ethylenically unsaturated groups (for example, (meth) acryl group, allyl group, styryl group, vinyloxy group, etc.) capable of addition reaction / polymerization reaction with radical species, cationic polymerizable group (epoxy) Groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups), and the like. Preferred are groups having an ethylenically unsaturated group.

  The average number of cross-linkable or polymerizable functional groups contained in the dispersant per molecule is preferably 2 or more, more preferably 5 or more, and particularly preferably 10 or more. Moreover, the crosslinking or polymerizable functional group contained in the dispersant may contain a plurality of types in one molecule.

In the preferred dispersant for use in the present invention, examples of the repeating unit having an ethylenically unsaturated group in the side chain include poly-1,2-butadiene and poly-1,2-isoprene structures or (meth) acrylic acid. An ester or amide repeating unit having a specific residue (the -COOR or -CONHR R group) bound thereto can be used. Examples of the specific residue (R _{group), - (CH 2) n} -CR 1 = CR 2 R 3, - (CH 2 O) n-CH 2 CR 1 = CR 2 R 3, - (CH ₂ CH ₂ O) n-CH ₂ CR ₁ = CR ₂ R ₃ ,-(CH ₂ ) n-NH-CO-O-CH ₂ CR ₁ = CR ₂ R ₃ ,-(CH ₂ ) n-O-CO -CR ₁ = CR ₂ R ₃ and-(CH ₂ CH ₂ O) ₂ -X (R _{1 to} R ₃ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, or an alkoxy group. A group, an aryloxy group, R ₁ and R ₂ or R ₃ may combine with each other to form a ring, n is an integer of 1 to 10, and X is a dicyclopentadienyl residue. There are). Specific examples of the ester _{residue, -CH 2 CH = CH 2,} -CH 2 CH 2 O-CH 2 CH = CH 2, -CH 2 CH 2 OCOCH = CH 2, -CH 2 CH 2 OCOC (CH 3 _{) = CH 2, -CH 2 C} (CH 3) = CH 2, -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 -NHCOO -CH ₂ CH = CH ₂ and _{-CH 2 CH 2 O-X (} X is a dicyclopentadienyl residue) are included. Specific examples of the amide _{residue, -CH 2 CH = CH 2,} -CH 2 CH 2 -Y (Y is 1-cyclohexenyl residue) and _{-CH 2 CH 2 -OCO-CH =} CH 2, -CH ₂ CH ₂ —OCO—C (CH ₃ ) ═CH ₂ is included.

  In the dispersant having an ethylenically unsaturated group, a free radical (a polymerization initiation radical or a growth radical of a polymerization process of a polymerizable compound) is added to the unsaturated bond group, and the polymer compound is directly or between molecules. Addition polymerization is carried out through the polymerization chain, and a crosslink is formed between the molecules to cure. Alternatively, atoms in the molecule (for example, hydrogen atoms on carbon atoms adjacent to the unsaturated bond group) are extracted by free radicals to form polymer radicals that are bonded together to form a bridge between the molecules. Harden.

  A method for introducing a cross-linkable or polymerizable functional group into the side chain is, for example, as described in JP-A-3-249653, etc., a crosslinkable or polymerizable functional group-containing monomer (for example, allyl (meth) acrylate, glycidyl (meth) acrylate, Copolymerization of trialkoxysilylpropyl methacrylate, etc., copolymerization of butadiene or isoprene, copolymerization of vinyl monomers having a 3-chloropropionic acid ester moiety followed by dehydrochlorination, crosslinking or polymerization by polymer reaction Can be synthesized by introduction of a functional group (for example, polymer reaction of an epoxy group-containing vinyl monomer to a carboxyl group-containing polymer).

The crosslinkable or polymerizable functional group-containing unit may constitute all repeating units other than the anionic group-containing repeating unit, but preferably 5 to 50 mol% of all the crosslinking or repeating units, particularly Preferably it is 5-30 mol%.
A preferable dispersant of the present invention may be a copolymer with a suitable monomer other than a monomer having a crosslinkable or polymerizable functional group or an anionic group. Although it does not specifically limit regarding a copolymerization component, It selects from various viewpoints, such as dispersion stability, compatibility with another monomer component, and the intensity | strength of a formed film. Preferable examples include methyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, styrene and the like.
The form of the preferable dispersant of the present invention is not particularly limited, but is preferably a block copolymer or a random copolymer, and particularly preferably a random copolymer from the viewpoint of cost and synthetic ease.

  Specific examples of the dispersant preferably used in the present invention are shown below, but the dispersant for the present invention is not limited thereto. Unless otherwise specified, it represents a random copolymer.

  The amount of the dispersant used with respect to the inorganic fine particles mainly composed of titanium dioxide is preferably in the range of 1 to 50% by mass, more preferably in the range of 5 to 30% by mass, and 5 to 20% by mass. Most preferably it is. Two or more dispersants may be used in combination.

(High refractive index layer and formation method thereof)
The inorganic fine particles mainly composed of titanium dioxide used for the high refractive index layer are used for forming the high refractive index layer in a dispersion state. In the dispersion of the inorganic fine particles, it is dispersed in a dispersion medium in the presence of the dispersant.
As the dispersion medium, a liquid having a boiling point of 60 to 170 ° C. is preferably used. Examples of dispersion media include water, alcohol (eg, methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketone (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), ester (eg, methyl acetate, ethyl acetate, Propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate), aliphatic hydrocarbons (eg, hexane, cyclohexane), halogenated hydrocarbons (eg, methylene chloride, chloroform, carbon tetrachloride), aromatic Hydrocarbon (eg, benzene, toluene, xylene), amide (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ether (eg, diethyl ether, dioxane, tetrahydrofuran), ether alcohol (eg, 1-methyl) Carboxymethyl-2-propanol) are included. Toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol are preferred.
Particularly preferred dispersion media are methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

The inorganic fine particles are dispersed using a disperser. Examples of dispersers include sand grinder mills (eg, pin bead mills), high speed impeller mills, pebble mills, roller mills, attritors and colloid mills. A sand grinder mill and a high-speed impeller mill are particularly preferred. Further, preliminary dispersion processing may be performed. Examples of the disperser used for the preliminary dispersion treatment include a ball mill, a three-roll mill, a kneader, and an extruder.
The inorganic fine particles are preferably made as fine as possible in the dispersion medium, and have a mass average diameter of 1 to 200 nm. Preferably it is 5-150 nm, More preferably, it is 10-100 nm, Most preferably, it is 10-80 nm.
By refining the inorganic fine particles to 200 nm or less, a high refractive index layer that does not impair the transparency can be formed.

  The high refractive index layer used in the present invention is prepared by adding a binder (for example, an ionizing radiation curable polyfunctional monomer or a polyfunctional monomer exemplified in the description of the hard coat layer) to a dispersion obtained by dispersing inorganic fine particles in a dispersion medium as described above. Functional oligomer, etc.), photopolymerization initiator, sensitizer, coating solvent, etc. are added to form a coating composition for forming a high refractive index layer, and a coating composition for forming a high refractive index layer is applied on the hard coat layer. Thus, it is preferably formed by curing by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound (for example, a polyfunctional monomer or a polyfunctional oligomer). As specific examples of the binder, the photopolymerization initiator, the sensitizer, and the coating solvent, the compounds exemplified in the hard coat layer can be used.

Further, it is preferable to cause the binder of the high refractive index layer to undergo a crosslinking reaction or a polymerization reaction with the dispersant simultaneously with or after the application of the layer.
The binder of the high refractive index layer thus prepared is, for example, the above-mentioned preferred dispersant and an ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer cross-linked or polymerized, and the binder is anionic. The base is incorporated. Furthermore, the binder of the high refractive index layer has a function in which the anionic group maintains the dispersed state of the inorganic fine particles, and the cross-linked or polymerized structure imparts a film forming ability to the binder to contain the inorganic fine particles. Improves physical strength, chemical resistance, and weather resistance.

The inorganic fine particles have a function of controlling the refractive index of the high refractive index layer and a function of suppressing curing shrinkage.
In the high refractive index layer, the inorganic fine particles are preferably dispersed as finely as possible, and the mass average diameter is 1 to 200 nm. The mass average diameter of the inorganic fine particles in the high refractive index layer is preferably 5 to 150 nm, more preferably 10 to 100 nm, and most preferably 10 to 80 nm.
By refining the inorganic fine particles to 200 nm or less, a high refractive index layer that does not impair the transparency can be formed.

The content of the inorganic fine particles in the high refractive index layer is preferably 10 to 90% by mass, more preferably 15 to 80% by mass, and particularly preferably 15 to 75% by mass with respect to the mass of the high refractive index layer. . Two or more inorganic fine particles may be used in combination in the high refractive index layer.
Since the low refractive index layer is provided on the high refractive index layer, the refractive index of the high refractive index layer is preferably higher than the refractive index of the transparent support.
The high refractive index layer contains an ionizing radiation curable compound containing an aromatic ring, an ionizing radiation curable compound containing a halogenated element other than fluorine (for example, Br, I, Cl, etc.), and atoms such as S, N, P, etc. Binders obtained by crosslinking or polymerization reaction such as ionizing radiation curable compounds can also be preferably used.
The refractive index of the high refractive index layer is preferably 1.55 to 2.40, more preferably 1.60 to 2.20, still more preferably 1.65 to 2.10, and most preferably 1.80. ~ 2.00.
For example, when three layers of a medium refractive index layer, a high refractive index layer, and a low refractive index layer are provided in this order on the hard coat layer, the refractive index of the medium refractive index layer is 1.55-1.80, and the refractive index of the high refractive index layer The refractive index is preferably 1.80 to 2.40, and the refractive index of the low refractive index layer is preferably 1.20 to 1.46.

In addition to the above components (inorganic fine particles, polymerization initiators, photosensitizers, etc.), the high refractive index layer includes resins, surfactants, antistatic agents, coupling agents, thickeners, anti-coloring agents, and coloring. Agents (pigments, dyes), antifoaming agents, leveling agents, flame retardants, UV absorbers, infrared absorbers, adhesion-imparting agents, polymerization inhibitors, antioxidants, surface modifiers, conductive metal particles, etc. It can also be added.
The film thickness of the high refractive index layer can be appropriately designed depending on the application. When using a high refractive index layer as an optical interference layer described later, the thickness is preferably 30 to 200 nm, more preferably 50 to 170 nm, and particularly preferably 60 to 150 nm.

(Other layers of antireflection film)
In order to produce an antireflection film having better antireflection performance, it is preferable to provide an intermediate refractive index layer having a refractive index between the refractive index of the high refractive index layer and the refractive index of the transparent support.
The medium refractive index layer is preferably produced in the same manner as described in the high refractive index layer of the present invention, and the refractive index can be adjusted by controlling the content of the inorganic fine particles in the film.
The antireflection film may be provided with layers other than those described above. For example, an adhesive layer, a shield layer, an antifouling layer, a sliding layer or an antistatic layer may be provided. The shield layer is provided to shield electromagnetic waves and infrared rays.

  The antireflection film of the present invention can be formed by the following method, but is not limited to this method.

[Adjustment of coating solution]
First, a coating solution containing components for forming each layer is prepared. In that case, the raise of the moisture content in a coating liquid can be suppressed by suppressing the volatilization amount of a solvent to the minimum. The moisture content in the coating solution is preferably 5% or less, more preferably 2% or less. The suppression of the volatilization amount of the solvent is achieved by improving the sealing property at the time of stirring after putting each material into the tank, minimizing the air contact area of the coating liquid at the time of liquid transfer operation, and the like. Moreover, you may provide the means to reduce the moisture content in a coating liquid during application | coating, or before and behind that.

  Filtration capable of removing almost all foreign substances (pointing to 90% or more) corresponding to the dry film thickness (about 50 nm to 120 nm) of the low refractive index layer directly formed on the coating liquid for forming the hard coat layer It is preferable to Since the light-transmitting fine particles for imparting light diffusivity are equal to or greater than the film thickness of the low refractive index layer, the filtration is performed on the intermediate liquid to which all materials other than the light-transmitting fine particles are added. Is preferred. In addition, when a filter capable of removing foreign substances having a small particle diameter as described above is not available, almost all foreign substances corresponding to the wet film thickness (about 1 to 10 μm) of the layer directly formed thereon are removed. It is preferable to perform filtration. By such means, the point defects of the layer formed directly thereon can be reduced.

[Coating method]
Each layer of the antireflection film of the present invention can be formed by the following coating method, but is not limited to this method.
Known methods such as dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, extrusion coating (see US Pat. No. 2,681,294), and micro gravure coating are available. Of these, the micro gravure coating method is preferred.

  The micro gravure coating method used in the present invention is a gravure roll having a diameter of about 10 to 100 mm, preferably about 20 to 50 mm and engraved with a gravure pattern on the entire circumference, below the support and in the transport direction of the support. The gravure roll is rotated in reverse with respect to the gravure roll, the excess coating liquid is scraped off from the surface of the gravure roll by a doctor blade, and a fixed amount of the coating liquid is removed from the support in a position where the upper surface of the support is in a free state. The coating method is characterized in that the coating liquid is transferred onto the lower surface for coating. A roll-shaped transparent support is continuously unwound, and at least one layer of at least one of a hard coat layer or a low refractive index layer containing a fluorine-containing polymer is provided on one side of the unwound support. Can be applied by.

  As coating conditions by the micro gravure coating method, the number of gravure patterns engraved on the gravure roll is preferably 50 to 800 / inch, more preferably 100 to 300 / inch, and the depth of the gravure pattern is 1 to 600 μm. Is preferable, 5 to 200 μm is more preferable, the rotation speed of the gravure roll is preferably 3 to 800 rpm, more preferably 5 to 200 rpm, and the conveyance speed of the support is 0.5 to 100 m / min. It is preferably 1 to 50 m / min.

<Wet application amount>
When forming the hard coat layer, it is preferable to apply the coating liquid in the range of 3 to 30 μm as the wet coating thickness directly or via another layer on the base film, from the viewpoint of preventing drying unevenness. Furthermore, the range of 6-20 micrometers is more preferable. Moreover, when forming a low refractive index layer, it is preferable to apply | coat a coating composition in the range of 1-10 micrometers as wet coating film thickness directly on an anti-glare layer or via another layer, More preferably, it is applied in the range of 5 μm.

[Dry]
The hard coat layer and the low refractive index layer are applied on the base film directly or via other layers, and then conveyed by a web to a heated zone to dry the solvent. The temperature of the drying zone at that time is preferably 25 ° C. to 140 ° C., the first half of the drying zone is preferably a relatively low temperature, and the latter half is preferably a relatively high temperature. However, it is preferably below the temperature at which components other than the solvent contained in the coating composition of each layer start to volatilize. For example, some commercially available photo radical generators used in combination with ultraviolet curable resins may volatilize around several tens of percent within a few minutes in warm air at 120 ° C. Some acrylate monomers and the like undergo volatilization in hot air at 100 ° C. In such a case, it is preferable that it is below the temperature at which components other than the solvent contained in the coating composition of each layer start to volatilize as described above.

Moreover, the dry wind after apply | coating the coating composition of each layer on a base film is 0.1-2 m / sec on the surface of a coating film, when the solid content concentration of the said coating composition is 1 to 50%. It is preferable to be in the range in order to prevent drying unevenness.
Moreover, after apply | coating the coating composition of each layer on a base film, the temperature difference of the conveyance roll and base film which contacts the surface opposite to the coating surface of a base film in a drying zone is 0 degreeC-20. Within the range of ° C., drying unevenness due to heat transfer unevenness on the transport roll can be prevented, which is preferable.

[Curing]
After the solvent drying zone, the coating is cured by passing through a zone where the coating is cured by ionizing radiation and / or heat on the web. The ionizing radiation used in the present invention can be used without limitation as long as the compound can be activated and cured by crosslinking with ultraviolet rays, electron beams, γ rays, etc., but ultraviolet rays and electron beams are preferable, and handling is particularly simple and high energy. UV rays are preferred in that they can be easily obtained. As the ultraviolet light source for photopolymerizing the ultraviolet reactive compound, any light source that generates ultraviolet light can be used. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used. Irradiation conditions vary depending on each lamp, but the irradiation light amount is preferably 10 mJ / cm ² or more, more preferably 50 mJ / cm ^{2 to} 10000 mJ / cm ² , and particularly preferably 50 mJ / cm ^{2 to} 2000 mJ / cm ^2. It is. At that time, the irradiation distribution in the width direction of the web is preferably 50 to 100%, more preferably 80 to 100%, including both ends with respect to the central maximum irradiation.

  The ultraviolet irradiation may be performed every time one layer is provided for each of a plurality of layers (medium refractive index layer, high refractive index layer, low refractive index layer) constituting the antireflection layer, or after lamination. Also good. Or you may irradiate combining these. From the viewpoint of productivity, it is preferable to irradiate ultraviolet rays after laminating multiple layers.

  Further, when the hard coat layer has a curing rate (100-residual functional group content) of a value of less than 100%, the low refractive index layer of the present invention is provided on the hard coat layer to reduce it by ionizing radiation and / or heat. When the refractive index layer is cured, it is preferable that the lower hard coat layer has a higher curing rate than before the low refractive index layer is provided, because the adhesion between the hard coat layer and the low refractive index layer is improved.

  Moreover, an electron beam can be used similarly. As an electron beam, 50 to 1000 keV, preferably 100 to 100, emitted from various electron beam accelerators such as a cockroft Walton type, a bandegraph type, a resonance transformation type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. An electron beam having an energy of 300 keV can be given.

When each layer is formed by a crosslinking reaction or a polymerization reaction with the ionizing radiation, the crosslinking reaction or the polymerization reaction is preferably performed in an atmosphere having an oxygen concentration of 10% by volume or less. By forming in an atmosphere having an oxygen concentration of 10% by volume or less, a layer having excellent physical strength and chemical resistance can be formed.
Preferably, it is formed by a crosslinking reaction or polymerization reaction of an ionizing radiation curable compound in an atmosphere having an oxygen concentration of 6% by volume or less, more preferably an oxygen concentration of 4% by volume or less, particularly preferably an oxygen concentration of 2 Volume% or less, most preferably 1 volume% or less.

  As a method of reducing the oxygen concentration to 10% by volume or less, it is preferable to replace the atmosphere (nitrogen concentration of about 79% by volume, oxygen concentration of about 21% by volume) with another gas, particularly preferably replacement with nitrogen (nitrogen purge). It is to be.

(Polarizer)
The polarizing plate of the present invention comprises a polarizing film and two protective films arranged on both sides thereof. As one protective film, the antireflection film of the present invention can be used. As the other protective film, a normal cellulose acetate film may be used. It is preferable to use it.
Furthermore, in the polarizing plate of the present invention, the other protective film is preferably an optical compensation film having an optically anisotropic layer made of a liquid crystalline compound with respect to the antireflection film.

Examples of the polarizing film include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. The iodine polarizing film and the dye polarizing film are generally produced using a polyvinyl alcohol film.
The slow support axis of the antireflection film or the cellulose acetate film and the transmission axis of the polarizing film are arranged so as to be substantially parallel.

The moisture permeability of the protective film is important for the productivity of the polarizing plate. The polarizing film and the protective film are bonded together with an aqueous adhesive, and the adhesive solvent is dried by diffusing in the protective film. The higher the moisture permeability of the protective film, the faster the drying and the higher the productivity. However, if the protective film is too high, moisture will enter the polarizing film depending on the usage environment (high humidity) of the liquid crystal display device. Polarization ability decreases.
The moisture permeability of the protective film is determined by the thickness, free volume, hydrophilicity / hydrophobicity, etc. of the transparent support or polymer film (and polymerizable liquid crystal compound).
When the light diffusion film and antireflection film of the present invention are used as a protective film for a polarizing plate, the moisture permeability is preferably 100 to 1000 g / m ² · 24 hrs, and more preferably 300 to 700 g / m ² · 24 hrs. preferable.
In the case of film formation, the thickness of the transparent support can be adjusted by lip flow rate and line speed, or stretching and compression. Since the moisture permeability varies depending on the main material to be used, it is possible to make a preferable range by adjusting the thickness.
In the case of film formation, the free volume of the transparent support can be adjusted by drying temperature and time. Also in this case, moisture permeability varies depending on the main material to be used, so that a preferable range can be obtained by adjusting the free volume.
The hydrophilicity / hydrophobicity of the transparent support can be adjusted by an additive. The moisture permeability can be increased by adding a hydrophilic additive to the free volume, and conversely, the moisture permeability can be lowered by adding a hydrophobic additive.
By independently controlling the moisture permeability, a polarizing plate having an optical compensation ability can be manufactured at low cost with high productivity.

(Optical compensation film)
The liquid crystal compound used in the optically anisotropic layer of the optical compensation film of the present invention may be a rod-like liquid crystal or a discotic liquid crystal. Including those that no longer show liquid crystallinity. The most preferable liquid crystal compound is a discotic liquid crystal.

Preferable examples of the rod-like liquid crystal include those described in JP 2000-304932A.
Examples of discotic liquid crystals include C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics Lett. A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), azacrown type, phenylacetylene type macrocycle, etc. can be mentioned.
The discotic liquid crystal generally has a structure in which these are used as a mother nucleus at the center of a molecule, and a linear alkyl group, an alkoxy group, a substituted benzoyloxy group, and the like are radially substituted, and exhibits liquid crystallinity. However, the molecule itself is not limited to the above description as long as the molecule itself has negative uniaxiality and can give a certain orientation.
In the present invention, the compound having a discotic structural unit in the optically anisotropic layer does not require that the compound finally formed in the optically anisotropic layer is a discotic compound. The molecular discotic liquid crystal has a group that reacts with heat, light or the like, and as a result, polymerized or cross-linked by reaction with heat, light or the like to have a high molecular weight and lose liquid crystallinity. Preferred examples of the discotic liquid crystal are described in JP-A-8-50206.

  The optically anisotropic layer of the present invention is a layer comprising a compound having a discotic structural unit, and the disc surface of the discotic structural unit is inclined with respect to the transparent support surface (that is, the protective film surface), and The angle formed by the disc surface of the discotic structural unit and the transparent support surface (that is, the protective film surface) is preferably changed in the depth direction of the optical anisotropic layer.

  The angle (tilt angle) of the surface of the discotic structural unit generally increases or decreases in the depth direction of the optical anisotropic layer and with increasing distance from the bottom surface of the optical anisotropic layer. The tilt angle preferably increases with increasing distance. Furthermore, the change in the inclination angle includes continuous increase, continuous decrease, intermittent increase, intermittent decrease, change including continuous increase and continuous decrease, and intermittent change including increase and decrease. it can. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if the inclination angle includes a region that does not change, it is preferable that the inclination angle increases or decreases as a whole. Further, the inclination angle is preferably increased as a whole, and particularly preferably continuously changed.

  The optically anisotropic layer is generally formed by applying a solution obtained by dissolving a discotic compound and other compounds in a solvent onto an alignment film, drying, then heating to a discotic nematic phase formation temperature, and then aligning the discotic nematic phase (discotic nematic phase). ) Is maintained and cooled. Alternatively, the optically anisotropic layer is formed by applying a solution in which a discotic compound and other compounds (for example, a polymerizable monomer and a photopolymerization initiator) are dissolved in a solvent, drying the coating, and then drying the discotic nematic phase. It is obtained by heating to the formation temperature, followed by polymerization (by irradiation with UV light, etc.) and further cooling. The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline compound used in the present invention is preferably 70 to 300 ° C, particularly preferably 70 to 170 ° C.

  The tilt angle of the discotic unit on the support side can be generally adjusted by selecting a discotic compound or a material for the alignment film, or by selecting a rubbing treatment method. The inclination angle of the discotic unit on the surface side (air side) is generally selected from the discotic compound or other compounds (eg, plasticizer, surfactant, polymerizable monomer and polymer) used together with the discotic compound. Can be adjusted. Furthermore, the degree of change in the tilt angle can also be adjusted by the above selection.

  As the plasticizer, surfactant and polymerizable monomer, any compound is used as long as it has compatibility with the discotic compound and can change the tilt angle of the liquid crystalline discotic compound or does not inhibit the alignment. Can also be used. Among these, polymerizable monomers (eg, compounds having a vinyl group, a vinyloxy group, an acryloyl group, and a methacryloyl group) are preferable. The above compound is generally used in an amount of 1 to 50% by mass (preferably 5 to 30% by mass) based on the discotic compound. Furthermore, a polyfunctional acrylate is mentioned as an example of a preferable polymerizable monomer. The number of functional groups is preferably 3 or more, more preferably 4 or more. Most preferred is a hexafunctional monomer. A preferred example of the hexafunctional monomer is dipentaerythritol hexaacrylate. It is also possible to use a mixture of these polyfunctional monomers having different numbers of functional groups.

Any polymer can be used as the polymer as long as it is compatible with the discotic compound and can change the tilt angle of the liquid crystalline discotic compound. Examples of polymers include cellulose esters. Preferred examples of the cellulose ester include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose, and cellulose acetate butyrate. The polymer is generally 0.1 to 10% by mass (preferably 0.1 to 8% by mass, particularly 0.1 to 5% by mass) based on the discotic compound so as not to inhibit the alignment of the liquid crystalline discotic compound. ).
In the present invention, the optically anisotropic layer is composed of a discotic liquid crystal formed on an alignment film provided on a protective film (for example, a cellulose acetate film) or the like, and a rubbing composed of a polymer in which the alignment film is crosslinked. A treated membrane is preferred.

(Alignment film)
In the present invention, the alignment film provided for adjusting the alignment of the liquid crystalline compound of the optically anisotropic layer is preferably a layer composed of two kinds of crosslinked polymers. It is preferable to use at least one of the two types of a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent. The alignment film is formed by reacting a polymer having a functional group or a polymer having a functional group introduced therein with light, heat, pH change, or the like, or a cross-linking that is a compound having a high reaction activity. It can be formed by introducing a bonding group derived from a crosslinking agent between the polymers using an agent and crosslinking the polymers.

  Such crosslinking is usually carried out by applying a coating liquid containing the above polymer or a mixture of a polymer and a crosslinking agent on a transparent support, followed by heating or the like. As long as it can be ensured, a cross-linking treatment may be performed at any stage after the alignment film is coated on the support until the final polarizing plate is obtained. When the optically anisotropic layer formed on the alignment film is formed of a discotic compound, it is preferable to sufficiently crosslink after aligning the compound, considering the orientation of the discotic compound. That is, when a coating solution containing a polymer and a crosslinking agent capable of crosslinking the polymer is applied on the support, after heating and drying (in general, crosslinking is performed, but when the heating temperature is low, discotic nematic When the film is heated to the phase formation temperature, the crosslinking further proceeds), a rubbing treatment is performed to form an alignment film, and then a coating solution containing a compound having a disk-like structural unit is applied onto the alignment film, and the discotic nematic phase After heating above the formation temperature, the optical anisotropic layer is formed by cooling.

  As the polymer used in the alignment film in the present invention, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used. Of course, some polymers are possible. Examples of the polymer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleimide copolymer, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylolacrylamide), styrene / vinyl toluene copolymer. , Chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethyl cellulose, polyethylene, polypropylene and polycarbonate, gelatin, etc. Examples thereof include compounds such as polymers and silane coupling agents. Examples of preferred polymers are water-soluble polymers such as poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyville alcohol, and modified polyvinyl alcohol, and gelatin, polyville alcohol, and modified polyvinyl alcohol are preferred. Mention may be made of bil alcohol and modified polyvinyl alcohol.

Among the above polymers, polyvinyl alcohol or modified polyvinyl alcohol is preferable, and two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization are most preferably used in combination.
The polyvinyl alcohol has, for example, a saponification degree of 70 to 100%, generally a saponification degree of 80 to 100%, and more preferably a saponification degree of 85 to 95%. As a polymerization degree, the range of 100-3000 is preferable. Examples of the modified polyvinyl alcohol include those modified by copolymerization (for example, COONa, Si (OX) ₄ , N (CH ₃ ) ₃ .Cl, C ₉ H ₁₉ COO, SO ₃ , Na, C ₁₂ H ₂₅ Etc.), modified by chain transfer (modified groups such as COONa, SH, C ₁₂ H ₂₅ etc. are introduced), modified by block polymerization (modified groups such as , COOH, CONH ₂ , COOR, C ₆ H _{5 and the} like are introduced). Among these, unmodified or modified polyvinyl alcohol having a saponification degree of 80 to 100% is preferable, and unmodified or alkylthio-modified polyvinyl alcohol having a saponification degree of 85 to 95% is more preferable.
A method for synthesizing these modified polymers, a method for measuring a visible absorption spectrum, a method for determining the introduction rate, and the like are described in detail in JP-A-8-338913.

  Specific examples of the crosslinking agent used together with the polymer such as polyvinyl alcohol include the following, and these include the above water-soluble polymers, particularly polyvinyl alcohol and modified polyvinyl alcohol (including the above-mentioned specific modified products). It is preferable when used in combination with. For example, activating aldehydes (eg, formaldehyde, glyoxal and glutaraldehyde), N-methylol compounds (eg, dimethylolurea and methyloldimethylhydantoin), dioxane derivatives (eg, 2,3-dihydroxydioxane), carboxyl groups (Eg, carbenium, 2-naphthalenesulfonate, 1,1-bispyrrolidino-1-chloropyridinium and 1-morpholinocarbonyl-3- (sulfonatoaminomethyl)), active vinyl compounds (eg, 1,3) , 5-triacroyl-hexahydro-s-triazine, bis (vinylsulfone) methane and N, N′-methylenebis- [β- (vinylsulfonyl) propionamide]), active halogen compounds (eg, 2,4-dichloro-6 -Hydroxy -S- triazine), isoxazole compounds, and dialdehyde starches, and the like. These can be used alone or in combination. In view of productivity, it is preferable to use an aldehyde having a high reaction activity, particularly glutaraldehyde.

  There is no particular limitation on the cross-linking agent, and the amount of the additive added tends to improve as the moisture resistance is increased. However, 0.1 to 20% by mass is preferable, and 0.5 to 15% by mass is particularly preferable because the alignment ability as the alignment film is lowered when 50% by mass or more is added to the polymer. In this case, the alignment film may contain some crosslinking agent that has not reacted even after the crosslinking reaction is completed, but the amount of the crosslinking agent may be 1.0% by mass or less in the alignment film. Preferably, it is particularly preferably 0.5% by mass or less. If the cross-linking agent is contained in the alignment film in an amount exceeding 1.0 mass, sufficient durability cannot be obtained. That is, when used in a liquid crystal display device, reticulation may occur when used for a long time or when left in a high temperature and high humidity atmosphere for a long time.

The alignment film of the present invention can be formed by applying a coating liquid containing the polymer and the crosslinking agent, which are alignment film forming materials, on a transparent support, followed by drying by heating (crosslinking) and rubbing treatment. it can. As described above, the crosslinking reaction may be performed at an arbitrary time after coating on the transparent support. And when using water-soluble polymers, such as said polyvinyl alcohol, as an orientation film formation material, it is preferred that a coating liquid is a mixed solvent of organic solvents, such as methanol and water, which has a defoaming action, and the ratio is mass. The ratio of water: methanol is generally 0: 100 to 99: 1, preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an alignment film and also an optically anisotropic layer reduces remarkably. Examples of the coating method include a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a bar coating method, and an E type coating method. The E-type coating method is particularly preferable. The film thickness is preferably 0.1 to 10 μm.
Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours. Preferably, it is 5 minutes to 30 minutes. The pH is also preferably set to an optimum value for the cross-linking agent to be used. When glutaraldehyde is used as the cross-linking agent, the pH is preferably 4.5 to 5.5, particularly preferably 5.

The alignment film is provided on the transparent support or through an undercoat layer that can adhere the transparent support and the alignment film. The undercoat layer is not particularly limited as long as it can improve the adhesion between the transparent support and the alignment film.
The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above. The alignment film functions so as to define the alignment direction of the liquid crystalline discotic compound provided thereon.

  For the rubbing treatment, a treatment method widely used as a liquid crystal alignment treatment process of the LCD can be used. That is, a method of obtaining alignment by rubbing the surface of the alignment film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are planted on average.

(Transparent support on which optically anisotropic layer is coated)
The transparent support on which the optically anisotropic layer is provided is preferably a cellulose acetate film and may be optically uniaxial or biaxial.
Since the transparent support on which the optically anisotropic layer is coated itself plays an optically important role, the Re retardation value of the transparent support is 0 to 200 nm, and the Rth retardation value is 70. It is preferable to adjust to 400 nm.
When two optically anisotropic cellulose acetate films are used in the liquid crystal display device, the Rth retardation value of the film is preferably 70 to 250 nm.
When one optically anisotropic cellulose acetate film is used for the liquid crystal display device, the Rth retardation value of the film is preferably 150 to 400 nm.

  In addition, it is preferable that the birefringence ((DELTA) n: nx-ny) of a cellulose acetate film is 0.00 thru | or 0.002. The birefringence {(nx + ny) / 2−nz} in the thickness direction of the cellulose acetate film is preferably 0.001 to 0.04.

  The retardation value (Re) is calculated according to the following mathematical formula (2).

  Formula (2): Re retardation value = (nx−ny) × d

  In the formula, nx is the refractive index in the slow axis direction in the plane of the retardation plate (maximum refractive index in the plane), and ny is the refraction in the direction perpendicular to the slow axis in the plane of the retardation plate. Rate. d is the thickness of the film whose unit is nm.

  The Rth retardation value is calculated according to the following mathematical formula (3).

  Formula (3): Rth retardation value = {(nx + ny) / 2−nz} × d

  In the formula, nx is the refractive index in the slow axis direction (the direction in which the refractive index is maximum) in the film plane. ny is the refractive index in the fast axis direction (direction in which the refractive index is minimized) in the film plane. nz is the refractive index in the thickness direction of the film. d is the thickness of the film whose unit is nm.

(Liquid crystal display device)
The antireflection film and polarizing plate of the present invention can be advantageously used in image display devices such as liquid crystal display devices, and are preferably used as the outermost layer of the display.
The liquid crystal display device has a liquid crystal cell and two polarizing plates arranged on both sides thereof, and the liquid crystal cell carries a liquid crystal between two electrode substrates. Further, one optically anisotropic layer may be disposed between the liquid crystal cell and one polarizing plate, or two optically anisotropic layers may be disposed between the liquid crystal cell and both polarizing plates.

  The liquid crystal cell is preferably in TN mode, VA mode, OCB mode, IPS mode or ECB mode.

In a TN mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and are twisted and aligned at 60 to 120 °.
The TN mode liquid crystal cell is most frequently used as a color TFT liquid crystal display device, and is described in many documents.

In a VA mode liquid crystal cell, rod-like liquid crystal 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) Liquid crystal cell (SID97, Digestof Tech. Papers (preliminary report) 28 (1997) 845) in which the VA mode is converted into a multi-domain (MVA mode) in order to expand the viewing angle (3) A 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 of the Japan Liquid Crystal Society) 1998)) and (4) SURVAVAL mode liquid crystal cells (presented at LCD International 98).

  The OCB mode liquid crystal cell is a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in substantially opposite directions (symmetrically) in the upper and lower portions of the liquid crystal cell. US Pat. Nos. 4,583,825 and 5,410,422. It is disclosed in each specification. Since the rod-like liquid crystal molecules are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. Therefore, this liquid crystal mode is called an OCB (Optically Compensatory Bend) liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.

  The IPS mode liquid crystal cell is a type in which a nematic liquid crystal is switched by applying a lateral electric field. IDRC (Asia Display '95), pp. 577-580 and pp. 707-710.

  In the ECB mode liquid crystal cell, rod-like liquid crystalline molecules are substantially horizontally aligned when no voltage is applied. The ECB mode is one of the liquid crystal display modes having the simplest structure, and is described in detail in, for example, Japanese Patent Laid-Open No. 5-203946.

The present invention will be specifically described in the following examples, but the present invention is not limited thereto.
(Example 1)
(Preparation of coating liquid A for hard coat layer)
The following composition was put into a mixing tank and stirred to obtain a hard coat layer coating solution A.

(Coating liquid A composition for hard coat layer)
Desolite Z7404 100 parts by mass (Zirconia fine particle-containing hard coat composition liquid: solid content concentration 60 wt%, zirconia fine particle content 70 wt% vs. solid content, average particle diameter of about 20 nm, solvent composition MIBK: MEK = 9: 1, manufactured by JSR Corporation )
31 parts by mass of DPHA (UV curable resin: manufactured by Nippon Kayaku Co., Ltd.)
KBM-5103 10 parts by mass (Silane coupling agent: Shin-Etsu Chemical Co., Ltd.)
KE-P150 8.9 parts by mass (1.5 μm silica particles: manufactured by Nippon Shokubai Co., Ltd.)
MXS-300 3.4 parts by mass (3.0 μm crosslinked PMMA particles: manufactured by Soken Chemical Co., Ltd.)
Methyl ethyl ketone (MEK) 29 parts by mass Methyl isobutyl ketone (MIBK) 13 parts by mass The above 1.5 μm silica particles mean silica particles having an average particle size of 1.5 μm, and 3.0 μm crosslinked PMMA particles have an average particle size of 3. It means 0 μm cross-linked polymethylmethacrylate particles. These particles are translucent particles.

(Preparation of coating liquid B for hard coat layer)
The following composition was put into a mixing tank and stirred to obtain a hard coat layer coating solution B.

Desolite Z7404 100 parts by mass (Zirconia fine particle-containing hard coat composition liquid: solid content concentration 60 wt%, zirconia fine particle content 70 wt% vs. solid content, average particle diameter of about 20 nm, solvent composition MIBK: MEK = 9: 1, manufactured by JSR Corporation )
31 parts by mass of DPHA (UV curable resin: manufactured by Nippon Kayaku Co., Ltd.)
KBM-5103 10 parts by mass (Silane coupling agent: Shin-Etsu Chemical Co., Ltd.)
KE-P150 4.3 parts by mass (1.5 μm silica particles: manufactured by Nippon Shokubai Co., Ltd.)
Methyl ethyl ketone (MEK) 29 parts by weight Methyl isobutyl ketone (MIBK) 13 parts by weight

(Preparation of titanium dioxide fine particle dispersion)
As titanium dioxide fine particles, titanium dioxide fine particles (MPT-129C, manufactured by Ishihara Sangyo Co., Ltd.) containing cobalt and surface-treated with aluminum hydroxide and zirconium hydroxide were used.
The following dispersant (38.6 g) and cyclohexanone (704.3 g) were added to 257.1 g of the particles and dispersed by dynomill to prepare a titanium dioxide dispersion having a mass average diameter of 70 nm.

Dispersant

(Preparation of coating solution for medium refractive index layer)
The following composition was put into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a coating solution for a medium refractive index layer.

(Medium refractive index layer coating solution composition)
Titanium dioxide fine particle dispersion 100 parts by mass DPHA 66 parts by mass (UV curable resin: manufactured by Nippon Kayaku Co., Ltd.)
Irgacure 907 3.5 parts by mass (photopolymerization initiator: manufactured by Ciba Geigy)
Kaya Cure DETX 1.2 parts by mass (photosensitizer: Nippon Kayaku Co., Ltd.)
Methyl ethyl ketone (MEK) 543 parts by mass Cyclohexanone 2103 parts by mass

(Preparation of coating solution for high refractive index layer)
The following composition was put into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a coating solution for a high refractive index layer.

(Coating solution composition for high refractive index layer)
Titanium dioxide fine particle dispersion 100 parts by mass DPHA 8.2 parts by mass (UV curable resin: manufactured by Nippon Kayaku Co., Ltd.)
Irgacure 907 0.68 parts by mass (photopolymerization initiator: Ciba Geigy)
Kaya Cure DETX 0.22 parts by mass (photosensitizer: Nippon Kayaku Co., Ltd.)
Methyl ethyl ketone (MEK) 78 parts by mass Cyclohexanone 243 parts by mass

(Preparation of sol solution a)
A reactor equipped with a stirrer and a reflux condenser, 120 parts by mass of methyl ethyl ketone, 100 parts by mass of acryloyloxypropyltrimethoxysilane (KBM-5103 (trade name); manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts by mass of diisopropoxyaluminum ethyl acetoacetate After adding a part and mixing, 30 mass parts of ion-exchange water was added, and it was made to react at 60 degreeC for 4 hours, Then, it cooled to room temperature, and obtained the sol liquid a. The mass average molecular weight was 1800, 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.

(Synthesis of perfluoroolefin copolymer (1))
Into a stainless steel autoclave with a stirrer of 100 ml, 40 ml of ethyl acetate, 14.7 g of hydroxyethyl vinyl ether and 0.55 g of dilauroyl peroxide were charged, and the inside of the system was deaerated and replaced with nitrogen gas. Furthermore, 25 g of hexafluoropropylene (HFP) was introduced into the autoclave and the temperature was raised to 65 ° C. The pressure when the temperature in the autoclave reached 65 ° C. was 0.53 MPa (5.4 kg / cm ² ). The reaction was continued for 8 hours while maintaining the temperature, and when the pressure reached 0.31 MPa (3.2 kg / cm ² ), the heating was stopped and the mixture was allowed to cool. When the internal temperature dropped to room temperature, unreacted monomers were driven out, the autoclave was opened, and the reaction solution was taken out. The obtained reaction solution was poured into a large excess of hexane, and the polymer was precipitated by removing the solvent by decantation. Further, this polymer was dissolved in a small amount of ethyl acetate and reprecipitated twice from hexane to completely remove the residual monomer. After drying, 28 g of polymer was obtained. Next, 20 g of the polymer was dissolved in 100 ml of N, N-dimethylacetamide, and 11.4 g of acrylic acid chloride was added dropwise under ice cooling, followed by stirring at room temperature for 10 hours. Ethyl acetate was added to the reaction solution, washed with water, the organic layer was extracted and concentrated, and the resulting polymer was reprecipitated with hexane to obtain 19 g of perfluoroolefin copolymer (1). The resulting polymer had a refractive index of 1.421.

(Preparation of hollow silica fine particle dispersion)
Hollow silica fine particle sol (Isopropyl alcohol silica sol, CS60-IPA manufactured by Catalyst Chemical Industry Co., Ltd., average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20%, silica particle refractive index 1.31) in 500 parts, acryloyloxypropyl After adding 30 parts of trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-5103) and 1.5 parts of diisopropoxyaluminum ethyl acetate, 9 parts of ion-exchanged water were added. After reacting at 60 ° C. for 8 hours, the mixture was cooled to room temperature, and 1.8 parts of acetylacetone was added to obtain a hollow silica dispersion. The resulting hollow silica dispersion had a solid content concentration of 18% by mass and a refractive index after solvent drying of 1.31.

(Preparation of coating solution A for low refractive index layer)
The following composition was put into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore diameter of 1 μm to prepare a coating solution A for a low refractive index layer.

(Composition of coating liquid A for low refractive index layer)
DPHA (UV curable resin: Nippon Kayaku Co., Ltd.) 1.4 parts by mass Perfluoroolefin copolymer (1) 5.6 parts by mass Hollow silica fine particle dispersion 20.0 parts by mass RMS-033 0.7 Mass parts (reactive silicone: manufactured by Gelest Co., Ltd.)
Irgacure 907 0.2 parts by mass (photopolymerization initiator: manufactured by Ciba Geigy)
Sol liquid a 6.2 parts by mass Methyl ethyl ketone (MEK) 306.9 parts by mass Cyclohexanone 9.0 parts by mass

(Preparation of coating solution B for low refractive index layer)
The following composition was put into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore diameter of 1 μm to prepare a coating solution B for a low refractive index layer.

(Composition of coating liquid B for low refractive index layer)
DPHA 1.4 parts by mass (UV curable resin: Nippon Kayaku Co., Ltd.)
Perfluoroolefin copolymer (1) 5.6 parts by mass Silica fine particle dispersion 12.0 parts by mass (Products with different particle sizes of MEK-ST, average particle size 45 nm: manufactured by Nissan Chemical Co., Ltd.)
RMS-033 0.7 parts by mass (reactive silicone: manufactured by Gelest Co., Ltd.)
Irgacure 907 0.2 parts by mass (photopolymerization initiator: manufactured by Ciba Geigy)
Sol liquid a 6.2 parts by mass Methyl ethyl ketone (MEK) 306.9 parts by mass Cyclohexanone 9.0 parts by mass

(Preparation of coating solution C for low refractive index layer)
The following composition was put into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating solution C for a low refractive index layer.

(Composition of coating liquid C for low refractive index layer)
Perfluoroolefin copolymer (1) 13.4 parts by mass RMS-033 0.7 parts by mass (reactive silicone: manufactured by Gelest Co., Ltd.)
Irgacure 907 0.2 parts by mass (photopolymerization initiator: manufactured by Ciba Geigy)
Methyl ethyl ketone (MEK) 306.9 parts by mass Cyclohexanone 9.0 parts by mass

(Preparation of antireflection film A-01)
A cellulose triacetate film (TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm is unwound as a support in the form of a roll, and the above-mentioned coating liquid A for hard coat layer is 135 lines / inch on the support. Using a micro gravure roll having a diameter of 60 mm and a doctor blade having a gravure pattern with a depth of 60 μm, coating was performed at a conveyance speed of 10 m / min, drying at 60 ° C. for 150 seconds, and further 160 W / cm under nitrogen purge. Using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.), the coating layer is cured by irradiating with ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 250 mJ / cm ² to form a hard coat layer 1 and winding It was. After curing, the rotation speed of the gravure roll was adjusted so that the thickness of the hard coat layer was 3.5 μm.
The refractive indexes of the binder containing zirconia fine particles constituting the hard coat layer 1, 1.5 μm silica particles, and 3.0 μm crosslinked PMMA particles were 1.62, 1.44, and 1.49, respectively.

The support coated with the hard coat layer 1 is unwound again, and the coating liquid A for the low refractive index layer is a micro gravure roll having a diameter of 180 lines / inch and a gravure pattern with a depth of 40 μm and a doctor blade. , Applied at a transfer speed of 10 m / min, dried at 120 ° C. for 150 seconds, further dried at 140 ° C. for 8 minutes, and then air-cooled metal halide lamp (I graphics ( The low refractive index layer 1 was formed and wound up by irradiating ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 900 mJ / cm ² . After curing, the rotation speed of the gravure roll was adjusted so that the thickness of the low refractive index layer was 100 nm.

(Preparation of antireflection film A-02 to 05)
The addition amount of KE-P150 (silica 1.5 μm particles) in the coating liquid A for hard coat layer is 7.0 parts by mass, 4.6 parts by mass, 2.1 parts by mass, and 0 parts by mass (without addition). The antireflection films A-02, A-03, A-04, and A-05 were respectively the same as the antireflection film A-01 except that the hard coat layers 2, 3, 4, and 5 were formed by changing. Produced.

(Preparation of antireflection film A-06-08)
The amount of KE-P150 (silica 1.5 μm particles) added to the coating liquid A for hard coat layer was changed to 4.6 parts by mass, and the thickness of the hard coat layer was 3.2 μm, 3.0 μm, and 2.7 μm. Antireflection films A-06, A-07, and A-08 were produced in the same manner as the antireflection film A-01, except that the hard coat layers 6, 7, and 8 were formed as described above. The antireflection films A-07 and A-08 have a thin film thickness, and a concavo-convex structure of 3.0 μm crosslinked PMMA particles is formed on the surface of the hard coat layer. As a result, the surface roughness Ra of the antireflection film is 0.00. This is a comparative example exceeding 12 μm, 0.15 μm and 0.10 μm.

(Preparation of antireflection film A-09)
An antireflection film A-09 was produced in the same manner as the antireflection film A-01, except that the hard coat layer 9 was formed using the coating liquid B for hard coat layer.
The refractive index of the binder containing the zirconia fine particles constituting the hard coat layer 9 and the silica 1.5 μm particles was 1.62 and 1.44, respectively.

(Preparation of antireflection films A-10 and 11)
Hard coat layers 10 and 11 were formed by changing the addition amount of KE-P150 (silica 1.5 μm particles) in hard coat layer coating liquid B to 2.0 parts by mass and 0 parts by mass (without addition). Except that, antireflection films A-10 and A-11 were respectively produced in the same manner as antireflection film A-01. Antireflection film A-11 is a comparative example in which the hard coat layer does not contain translucent particles.

(Preparation of antireflection films A-12 and 13)
Antireflection is performed in the same manner as the antireflection films A-03 and A-09 except that the low refractive index layer 2 is formed on the hard coat layers 3 and 9 using the coating liquid B for low refractive index layer. Films A-12 and A-13 were produced. These antireflection films are comparative examples in which the hollow silica particles are not contained in the low refractive index layer.

(Preparation of antireflection films A-14 and 15)
Antireflection is performed in the same manner as the antireflection films A-03 and A-09 except that the low refractive index layer 3 is formed on the hard coat layers 3 and 9 using the coating liquid C for low refractive index layer. Films A-14 and A-15 were produced. These antireflection films are comparative examples in which the hollow silica particles are not contained in the low refractive index layer.

(Preparation of antireflection film A-16)
In the same manner as the antireflection film A-09, only the hard coat layer 9 was formed, and the film not formed with the low refractive index layer was designated as an antireflection film A-16 (Comparative Example).

(Preparation of antireflection film A-17)
A cellulose triacetate film (TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm was unwound as a support in a roll form, and a hard coat layer coating solution B was applied onto the support using a gravure coater. . After drying at 100 ° C., an irradiance of 400 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. ² , the coating layer was cured by irradiating with an irradiation dose of 300 mJ / cm ² to form a hard coat layer 12 having a thickness of 3.5 μm.

On the hard coat layer 12, a medium refractive index layer coating solution was coated using a gravure coater. After drying at 100 ° C., an illuminance of 550 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 240 W / cm while purging with nitrogen so that the atmosphere has an oxygen concentration of 1.0% by volume or less. ^2. An ultraviolet ray with an irradiation amount of 600 mJ / cm ² was irradiated to cure the coating layer to form a medium refractive index layer (refractive index 1.65, film thickness 67 nm).

On the medium refractive index layer, a coating solution for a high refractive index layer was applied using a gravure coater. After drying at 100 ° C., an illuminance of 550 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 240 W / cm while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. ^{2. The} coating layer was cured by irradiating with an ultraviolet ray having an irradiation amount of 600 mJ / cm ² to form a high refractive index layer (refractive index 1.93, film thickness 107 nm).

On the high refractive index layer, the coating liquid A for low refractive index layer was applied using a gravure coater. After drying at 80 ° C. and using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less, the illuminance is 550 mW / A low refractive index layer (refractive index: 1.43, film thickness: 86 nm) was formed by irradiating ultraviolet rays with a cm ² and an irradiation amount of 600 mJ / cm ² . Thus, the antireflection layer 3 was formed on the hard coat layer, and an antireflection film A-17 was produced.

(Preparation of antireflection films A-18 and 19)
Antireflective in the same manner as antireflective film A-09, except that Irgacure 907 contained in coating solution A for low refractive index layer was replaced with Irgacure 184 (photopolymerization initiator: manufactured by Ciba Geigy) or Exemplified Compound 21. Films A-18 and A-19 were respectively produced.

(Exemplary Compound 21)

  Further, for a series of antireflection films A-01 to A-19, TD80U as a support, Tinuvin327 (UV absorber: manufactured by Ciba Specialty Chemicals Co., Ltd.) contained in TD80U, and Tinuvin326 (UV absorber: Ciba Specialty) Antireflection films B-01 to B-19 were produced using a cellulose triacetate film produced by substituting Chemicals Co., Ltd.

(Saponification treatment of antireflection film)
A 1.5 mol / l aqueous sodium hydroxide solution was prepared and kept at 55 ° C. A 0.005 mol / l dilute sulfuric acid aqueous solution was prepared and kept at 35 ° C. The prepared antireflection film 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. Finally, the sample was thoroughly dried at 120 ° C.
In this way, a saponified antireflection film was produced.

(Preparation of polarizing plate PA-01 to 17 with antireflection film)
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. Affixed to one side of the polarizing film so that the support side (triacetyl cellulose) of the antireflective film is on the polarizing film side using a polyvinyl alcohol-based adhesive on the saponified antireflective films A-01 to A-17. I attached. Further, the disc surface of the discotic structural unit is inclined with respect to the film surface, and the angle formed by the disc surface of the discotic structural unit and the film surface changes in the depth direction of the optical anisotropic layer. A viewing angle widening film having an optical compensation layer (Wide View Film Super Ace, manufactured by Fuji Photo Film Co., Ltd.) was saponified and attached to the other side of the polarizing film using a polyvinyl alcohol adhesive. In this way, polarizing plates PA-01 to 17 were produced.

(Evaluation of antireflection film and polarizing plate)
The following items were evaluated about the obtained antireflection film and polarizing plate. The results are shown in Table 1.
(1) Centerline average roughness Ra
The surface roughness of the antireflection film was measured with an atomic force microscope (AFM: Atomic Force Microscope, SPI3800N, manufactured by Seiko Instruments Inc.).

(2) Haze The haze of the antireflection film was measured using a haze meter MODEL 1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.).

(3) Transmission image definition The transmission image definition of the antireflection film was measured with an optical comb of 0.5 mm using an image clarity measuring instrument (ICM-2D type) manufactured by Suga Test Instruments Co., Ltd.

(4) Integral reflectance The antireflection film is attached to an integrating sphere of a spectrophotometer V-550 (manufactured by JASCO Corporation), and the integral reflectance is measured in a wavelength region of 380 to 780 nm. The average reflectance at 650 nm was calculated and the antireflection property was evaluated.

(5) White blur The viewing-side polarizing plate provided in the liquid crystal display device (TH-15TA2, manufactured by Matsushita Electric Industrial Co., Ltd.) using a TN type liquid crystal cell is peeled off, and polarizing plates PA-01 to 17 are used instead. Was attached via an adhesive so that the antireflection film side was on the viewing side and the transmission axis of the polarizing plate was coincident with the polarizing plate attached to the product. The liquid crystal display device was displayed in black in a 1000 lux bright room, and was evaluated by the following criteria visually from various viewing angles.

(Judgment criteria for white-headedness)
A: No whitening at all B: Little whitening C: There is weak whitening D: There is strong whitening

(6) Goniophotometer Scattering Intensity Ratio Using an automatic goniophotometer GP-5 (manufactured by Murakami Color Research Laboratory Co., Ltd.), an anti-reflection film is placed perpendicular to the incident light, and in all directions The scattered light profile was measured across. The scattered light intensity at an exit angle of 30 ° was determined with respect to the light intensity at an exit angle of 0 °.

(7) Left and right color change About the liquid crystal display device created by the above-mentioned evaluation of white blurring, the yellow coloration degree of white display when the viewing angle is tilted to the left and right was visually evaluated according to the following criteria.

(Judgment criteria for left-right color change)
A: Do not feel yellow coloring B: Slightly yellow C: Slightly yellow D: Strongly yellow

(8) Viewing angle About the liquid crystal display device created by the evaluation of the above white blurring, the viewing angle of contrast 10 was calculated from the measurement of black display and white display using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM). .

(9) Steel wool scratch resistance Using a rubbing tester, a rubbing test was conducted under the following conditions.
Evaluation environmental conditions: 25 ° C., 60% RH
Rubbing material: Steel wool (manufactured by Nippon Steel Wool Co., Ltd., No. 0000) was wound around the rubbing tip (1 cm × 1 cm) of a tester 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.
A: Even if you look very carefully, no scratches are visible.
B: A weak wound is visible.
C: A moderate crack is visible.
D: There is a scratch that can be seen at first glance.

  From the results shown in Table 1, the following is clear. It was used for a liquid crystal display device by an anti-reflection film comprising a light-transmitting hard coat layer having internal scattering properties and a low refractive index layer containing hollow silica fine particles, and having an Ra of 0.10 μm or less. At the same time, anti-reflection, white blurring, and viewing angle characteristics have been improved to a very high level. Further, by stacking a middle / high / low refractive index layer and a multilayer optical interference layer, extremely excellent antireflection properties are exhibited.

  Further, with respect to the antireflection films A-09, A-18, and A-19, the number of rubbing in the steel wool scratch resistance evaluation was changed to 20 reciprocations. Gave superior results.

  Similar results were obtained for all of the antireflection films B-01 to B-19.

It is a schematic sectional drawing which shows the structural example of the antireflection film of this invention. It is a schematic sectional drawing which shows the structural example of the antireflection film of this invention. It is a schematic sectional drawing which shows the structural example of the antireflection film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent support body 2A, 2B Hard-coat layer 3 Low-refractive-index layer 4A, 4B Translucent particle 5 Middle refractive-index layer 6 High-refractive-index layer 10 Antireflection film 20 Antireflection film 30 Antireflection film

Claims (8)

An antireflection film having, on a transparent support, at least one hard coat layer and a low refractive index layer located on the outermost layer,
(I) The hard coat layer contains a binder and at least one kind of translucent particles having a refractive index different from that of the binder,
(Ii) The surface roughness Ra (centerline average roughness) of the antireflection film is 0.10 μm or less, and (iii) the low refractive index layer has an average particle diameter of 5 to 200 nm and a refractive index. Contains hollow silica fine particles having 1.17 to 1.40,
An antireflection film characterized by that.   The antireflection film according to claim 1, wherein the transmitted image definition of the antireflection film is 60% or more.   The antireflection film according to claim 1, wherein the haze is 10% or more.   The scattered light intensity at an output angle of 30 ° with respect to the light intensity at an output angle of 0 ° of the scattered light profile measured with a goniophotometer of the hard coat layer is 0.01% to 0.2%. Antireflection film in any one of 1-3.   The antireflection film according to any one of claims 1 to 4, further comprising at least one high refractive index layer having a higher refractive index than that of the transparent support on the hard coat layer.   A polarizing plate having both surfaces of a polarizing film sandwiched between protective films, wherein the antireflection film according to claim 1 is used for one protective film.   Of the two protective films, the protective film in which the antireflection film is not used is an optical compensation film having an optically anisotropic layer, and the optically anisotropic layer is a layer containing a compound having a discotic structural unit. Yes, the disc surface of the discotic structural unit is inclined with respect to the protective film surface, and the angle formed by the disc surface of the discotic structural unit and the protective film surface changes in the depth direction of the optical anisotropic layer. The polarizing plate according to claim 6.   A liquid crystal display device using the antireflection film according to any one of claims 1 to 5 or the polarizing plate according to any one of claims 6 and 7 as an outermost layer of a display.

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