JPWO2008010376A1 - Antireflection film - Google Patents

Abstract

In an antireflection film having at least a low refractive index layer on a transparent support directly or via another layer, the low refractive index layer contains at least two types of silica fine particles, and one type of silica fine particles is contained inside Is a hollow silica-based fine particle having a porous or hollow shape, and the other one type of silica fine particle is colloidal silica, and the average particle size of the colloidal silica is 1.1 to 20 of the average particle size of the hollow silica-based fine particle. An antireflection film having an arithmetic average roughness (Ra) of an outermost surface of less than 40 times and less than 40 to 500 nm.

Description

  The present invention relates to an antireflection film, and particularly relates to an antireflection film having excellent scratch resistance, low reflectance, and excellent visibility when used in a display device.

  For an antireflection film used on the outermost surface of an image display device such as a liquid crystal, a technique has been proposed in which an antireflection layer of an optical interference system is provided to achieve a low reflectance.

  As a technique for reducing the reflectance, there is a method of reducing the refractive index of the low refractive index layer on the outermost surface, and a low refractive index material or a method of reducing the refractive index by increasing the number of voids has been proposed. However, in any technique, the film strength and scratch resistance are weak points.

  A recently proposed technique using hollow silica-based fine particles having a porous or hollow interior (see, for example, Patent Documents 1 to 3) is a technique for improving film strength while maintaining a decrease in refractive index due to voids. is there. Nevertheless, the film strength is insufficient, and the low refractive index layer containing 20 mass% or more of hollow silica-based fine particles has a problem that the film strength falls below the practical film strength. In addition, the dispersion of hollow silica-based fine particles is subject to variations in pH between lots, so that the viscosity of the low refractive index layer coating composition is likely to vary, and it is applied after the low refractive index layer coating composition is prepared. In the meantime, alkali components such as ammonia are eluted from the inside of the hollow silica fine particles, and there is a problem that the viscosity of the low refractive index layer coating composition varies (increases).

  In addition, a method of forming a metal oxide film by applying a metal alkoxide typified by titanium alkoxide or silane alkoxide on the surface of a support, drying, and heating has been performed. However, this method requires a high heating temperature of 300 ° C. or higher and damages the support, and the heating temperature as described in JP-A-8-75904 has a relatively low heating temperature of 100 ° C. A long time was required for the production, and both had problems.

  On the other hand, as a method of forming a metal oxide film, for example, a method of forming a silica-based film as a base film of a functional film by a so-called sol-gel method (see Patent Document 4), A method of forming by a sol-gel method (see Patent Document 5) is known. However, this method also had insufficient scratch resistance.

In addition, the technique using a fluorine-based resin as a binder component (see, for example, Patent Documents 6 to 8) also has a problem that the film strength is weak although the refractive index is lowered. That is, there is a trade-off relationship between lowering the refractive index and film strength, and there is a need for improvement.
Japanese Patent Laid-Open No. 2001-167637 JP 2001-233611 A JP 2002-79616 A JP-A-11-269657 JP 2000-910 A JP 2003-236970 A JP 2003-240906 A JP 2003-255103 A

  The present invention has been made in view of the above problems, and an object thereof is to provide an antireflection film having excellent scratch resistance, low reflectance, and excellent visibility when used in a display device.

The above object of the present invention is achieved by the following configurations.
1. In an antireflection film having at least a low refractive index layer on a transparent support directly or via another layer, the low refractive index layer contains at least two types of silica fine particles, and one type of silica fine particles is contained inside Is a hollow silica-based fine particle having a porous or hollow shape, and the other one type of silica fine particle is colloidal silica, and the average particle size of the colloidal silica is 1.1 to 20 of the average particle size of the hollow silica-based fine particle. An antireflection film having an arithmetic average roughness (Ra) of an outermost surface of less than 40 times and less than 40 to 500 nm.
2. 2. The antireflection according to the item 1, wherein the transparent support has a hard coat layer and a low refractive index layer, and the arithmetic average roughness (Ra) of the surface of the hard coat layer is less than 60 to 700 nm. the film.
3. 3. The antireflection film as described in 1 or 2 above, wherein the surface of the transparent support has an arithmetic average roughness (Ra) of less than 50 to 1000 nm.
4). 4. The antireflection film as described in any one of 1 to 3 above, wherein the hard coat layer contains fluorine-containing acrylic resin fine particles.

  According to the present invention, it is possible to provide an antireflection film having excellent scratch resistance, low reflectance, and excellent visibility when used in a display device.

It is the schematic of the uneven | corrugated surface forming apparatus using an uneven | corrugated roller. It is the schematic of the uneven surface forming apparatus in a drying apparatus. It is the schematic which shows an example of the thin film formation apparatus of a 1 frequency high frequency voltage application system useful for this invention. It is the schematic which shows an example of the thin film formation apparatus of a 2 frequency high frequency voltage application system useful for this invention. It is a perspective view which shows an example of the structure of the electroconductive metal base material of a roll electrode, and the dielectric material coat | covered on it. It is a perspective view which shows an example of the structure of the electroconductive metal preform | base_material of a rectangular tube type electrode, and the dielectric material coat | covered on it.

Explanation of symbols

F base film G discharge gas G 'excited discharge gas P liquid feed pump 1 die 2 belt for casting 3, 3' uneven roller 4 back roll 5 tenter 6 film drying device 7 take-up roll 10 static electricity removing device 35a roll electrode 35A, 36A Metal base material 35A, 36B Dielectric 36a Square tube electrode 130 Atmospheric pressure plasma processing device 131 Atmospheric pressure plasma processing vessel 132 Discharge space 135 Roll electrode (first electrode)
136 Square tube electrode group (second electrode)
140 Electric field application means 141 First power supply 142 Second power supply 143 First filter 144 Second filter 150 Gas supply means 151 Gas generator 152 Air supply port 153 Exhaust port 160 Electrode temperature control means 161 Piping 164, 167 Guide rolls 165, 166 Nip roll 168, 169 Partition plate

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  Conventionally, there is a technique of using hollow silica-based fine particles in the low refractive index layer in order to reduce the reflectance, but in order to further reduce the reflectance by this method, it is necessary to increase the content of the hollow silica-based fine particles. there were. However, since the hollow silica-based fine particles are easily broken by an external pressure, the surface properties, particularly the surface hardness, of the antireflection film are lowered.

  As a result of diligent study, the present inventor, in an antireflection film having at least a low refractive index layer on the transparent support directly or via another layer, silica fine particles having different specific types and particle sizes in the low refractive index layer It has been found that the reflectance can be reduced without lowering the surface hardness of the antireflection film.

  Surprisingly, mixing different kinds of silica fine particles not only increases the content of one kind of hollow silica fine particles, but also has a greater effect of reducing the reflectance as well as the surface hardness. The other layers are various functional layers such as a hard coat layer and a high refractive index layer described later.

  About the mechanism in which such an effect is expressed, it is guessed as follows. By reducing the content of hollow silica-based fine particles that reduce surface physical properties, particularly surface hardness, and using colloidal silica that is difficult to reduce surface hardness, a decrease in surface hardness of the antireflection film is prevented. Moreover, by including silica fine particles having different types and particle sizes, voids are formed in the dried coating film, and the refractive index is reduced. Antiglare base material (Antiglare film whose arithmetic average roughness (Ra) of the surface of the transparent support is less than 50 to 1000 nm, or a hard coat layer on the transparent support, When an antireflection layer is formed on an antiglare film having a surface arithmetic average roughness (Ra) of less than 60 to 700 nm, colloidal silica having an average particle size larger than the average particle size of the hollow silica-based fine particles is mixed. Then, leveling during drying is hindered, and the film thickness becomes substantially uniform and the refractive index is reduced. At the same time, the antiglare irregularities are stored on the outermost surface of the antireflection film, and the antiglare property is not impaired.

  Hereinafter, the present invention will be described in detail.

(Low refractive index layer)
The refractive index of the low refractive index layer according to the present invention is lower than the refractive index of the transparent support that is the support, and is preferably in the range of 1.30 to 1.45 at 23 ° C. and a wavelength of 550 nm.

  The film thickness of the low refractive index layer is preferably 5 nm to 0.5 μm, more preferably 10 nm to 0.3 μm, and even more preferably 30 nm to 0.2 μm.

  The composition for forming a low refractive index layer used in the present invention contains at least two types of silica fine particles, and one of the silica fine particles is a hollow silica-based fine particle having a porous or hollow interior, One type of silica fine particles is colloidal silica, and the average particle size of the colloidal silica is 1.1 to less than 20 times the average particle size of the hollow silica-based fine particles.

(Hollow silica fine particles)
The hollow silica-based fine particles (hereinafter also simply referred to as hollow fine particles) in which the inside is porous or hollow will be described.

  The hollow fine particles are: (I) a composite particle comprising a porous particle and a coating layer provided on the surface of the porous particle, or (II) a cavity inside, and the content is a solvent, gas or porous substance It is a hollow particle filled with.

  The hollow particles are particles having cavities inside, and the cavities are surrounded by particle walls. The cavity is filled with contents such as a solvent, a gas, or a porous material used at the time of preparation. The average particle size of such hollow fine particles is 5 to 200 nm, preferably 10 to 70 nm. The particle diameter of the hollow fine particles is preferably monodispersed with a coefficient of variation of 1 to 40%. The average particle diameter can be measured from an electron micrograph taken with a scanning electron microscope (SEM) or the like. You may measure by the particle size distribution meter etc. which utilize a dynamic light scattering method, a static light scattering method, etc. The average particle size of the hollow fine particles to be used is appropriately selected according to the thickness of the transparent coating of the low refractive index layer to be formed, and is preferably 2/3 to 1/10 of the thickness of the transparent coating. These hollow fine particles are preferably used in a state of being dispersed in an appropriate medium in order to form a low refractive index layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol), ketone (for example, methyl ethyl ketone, methyl isobutyl ketone), and ketone alcohol (for example, diacetone alcohol) are preferable.

  The thickness of the coating layer of the composite particles or the thickness of the particle walls of the hollow particles is 1 to 20 nm, preferably 2 to 15 nm. In the case of composite particles, if the thickness of the coating layer is less than 1 nm, the particles may not be completely covered, and the coating liquid component can easily enter the composite particles to reduce the internal porosity. However, the effect of lowering the refractive index may not be obtained sufficiently. In addition, when the thickness of the coating layer exceeds 20 nm, the coating liquid component does not enter the inside, but the porosity (pore volume) of the composite particles is lowered and the effect of lowering the refractive index is sufficiently obtained. It may disappear. In the case of hollow particles, when the particle wall thickness is less than 1 nm, the particle shape may not be maintained, and even when the thickness exceeds 20 nm, the effect of lowering the refractive index may not be sufficiently exhibited. is there.

The coating layer of the composite particles or the particle wall of the hollow particles is preferably composed mainly of silica. In addition, components other than silica may be contained. Specifically, Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , WO _{3 and the} like. Examples of the porous particles constituting the composite particles include those made of silica, those made of silica and an inorganic compound other than silica, and those made of CaF ₂ , NaF, NaAlF ₆ , MgF, and the like. Among these, porous particles made of a composite oxide of silica and an inorganic compound other than silica are particularly preferable. Examples of inorganic compounds other than silica include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , WO _{3 and the} like. 1 type or 2 types or more can be mentioned. In such porous particles, the molar ratio MO _X / SiO ₂ when the silica is expressed by SiO ₂ and the inorganic compound other than silica is expressed in terms of oxide (MO _X ) is 0.0001 to 1.0, Preferably it is in the range of 0.001 to 0.3. It is difficult to obtain a porous particle having a molar ratio MO _X / SiO ₂ of less than 0.0001. Even if it is obtained, particles having a small pore volume and a low refractive index cannot be obtained. In addition, when the molar ratio MO _X / SiO _{2 of} the porous particles exceeds 1.0, the ratio of silica decreases, so that the pore volume increases and it is difficult to obtain a low refractive index. is there.

  The pore volume of such porous particles is desirably in the range of 0.1 to 1.5 ml / g, preferably 0.2 to 1.5 ml / g. If the pore volume is less than 0.1 ml / g, particles having a sufficiently reduced refractive index cannot be obtained. If the pore volume exceeds 1.5 ml / g, the strength of the fine particles is lowered, and the strength of the resulting coating may be lowered. is there.

  In addition, the pore volume of such porous particles can be determined by a mercury intrusion method. Examples of the contents of the hollow particles include a solvent, a gas, and a porous substance used at the time of preparing the particles. The solvent may contain an unreacted particle precursor used when preparing the hollow particles, the catalyst used, and the like. Moreover, what consists of the compound illustrated by the said porous particle as a porous substance is mentioned. These contents may be composed of a single component or may be a mixture of a plurality of components.

  As a method for producing such hollow fine particles, for example, the method for preparing composite oxide colloidal particles disclosed in paragraphs [0010] to [0033] of JP-A-7-133105 is suitably employed. Specifically, when the composite particles are composed of silica and an inorganic compound other than silica, hollow fine particles are produced from the following first to third steps.

First Step: Preparation of Porous Particle Precursor In the first step, an alkali aqueous solution of a silica raw material and an inorganic compound raw material other than silica is separately prepared in advance, or a silica raw material and an inorganic compound raw material other than silica are prepared in advance. A mixed aqueous solution is prepared, and this aqueous solution is gradually added to an aqueous alkaline solution having a pH of 10 or more while stirring according to the composite ratio of the target composite oxide to prepare a porous particle precursor.

  As the silica raw material, alkali metal, ammonium or organic base silicate is used. Sodium silicate (water glass) or potassium silicate is used as the alkali metal silicate. Examples of the organic base include quaternary ammonium salts such as tetraethylammonium salt, and amines such as monoethanolamine, diethanolamine, and triethanolamine. The ammonium silicate or the organic base silicate includes an alkaline solution obtained by adding ammonia, a quaternary ammonium hydroxide, an amine compound or the like to a silicic acid solution.

  In addition, alkali-soluble inorganic compounds are used as raw materials for inorganic compounds other than silica. Specifically, an oxo acid of an element selected from Al, B, Ti, Zr, Sn, Ce, P, Sb, Mo, Zn, W, etc., an alkali metal salt or alkaline earth metal salt of the oxo acid, ammonium And salts and quaternary ammonium salts. More specifically, sodium aluminate, sodium tetraborate, zirconyl ammonium carbonate, potassium antimonate, potassium stannate, sodium aluminosilicate, sodium molybdate, cerium ammonium nitrate, and sodium phosphate are suitable.

Although the pH value of the mixed aqueous solution changes simultaneously with the addition of these aqueous solutions, an operation for controlling the pH value within a predetermined range is not particularly required. The aqueous solution finally has a pH value determined by the type of inorganic oxide and the mixing ratio thereof. There is no restriction | limiting in particular in the addition rate of the aqueous solution at this time. Further, in the production of composite oxide particles, a dispersion of seed particles can be used as a starting material. The seed particles are not particularly limited, but inorganic oxides such as SiO ₂ , Al ₂ O ₃ , TiO ₂ or ZrO ₂ or fine particles of these composite oxides are used. Usually, these sols are used. Can do. Furthermore, the porous particle precursor dispersion obtained by the above production method may be used as a seed particle dispersion. When using a seed particle dispersion, the pH of the seed particle dispersion is adjusted to 10 or higher, and then an aqueous solution of the compound is added to the above-mentioned alkaline aqueous solution while stirring. Also in this case, it is not always necessary to control the pH of the dispersion. When seed particles are used in this way, it is easy to control the particle size of the porous particles to be prepared, and particles with uniform particle sizes can be obtained.

  The silica raw material and the inorganic compound raw material described above have high solubility on the alkali side. However, when both are mixed in this highly soluble pH region, the solubility of oxo acid ions such as silicate ions and aluminate ions decreases, and these composites precipitate and grow into fine particles, or seed particles. It grows on the top and particle growth occurs. Therefore, it is not always necessary to perform pH control as in the conventional method for precipitation and growth of fine particles.

The composite ratio of the silica and the inorganic compound other than silica in the first step is calculated by converting the inorganic compound to silica into an oxide (MO _X ), and the molar ratio of MO _X / SiO ₂ is 0.05 to 2.0, Preferably it is in the range of 0.2-2.0. Within this range, the pore volume of the porous particles increases as the proportion of silica decreases. However, even when the molar ratio exceeds 2.0, the pore volume of the porous particles hardly increases. On the other hand, when the molar ratio is less than 0.05, the pore volume becomes small. When preparing the hollow particles, the molar ratio of MO _X / SiO ₂ is desirably in the range of 0.25 to 2.0.

Second step: Removal of inorganic compound other than silica from porous particles In the second step, inorganic compounds other than silica (elements other than silicon and oxygen) are obtained from the porous particle precursor obtained in the first step. At least a portion is selectively removed. As a specific removal method, the inorganic compound in the porous particle precursor is dissolved and removed using a mineral acid or an organic acid, or is contacted with a cation exchange resin for ion exchange removal.

  The porous particle precursor obtained in the first step is a particle having a network structure in which silicon and an inorganic compound constituent element are bonded through oxygen. By removing the inorganic compound (elements other than silicon and oxygen) from the porous particle precursor in this way, porous particles having a larger porosity and a larger pore volume can be obtained. Further, if the amount of removing the inorganic oxide (elements other than silicon and oxygen) from the porous particle precursor is increased, the hollow particles can be prepared.

  In addition, prior to removing inorganic compounds other than silica from the porous particle precursor, fluorine-substituted, obtained by dealkalizing an alkali metal salt of silica into the porous particle precursor dispersion obtained in the first step. It is preferable to add a silicic acid solution containing an alkyl group-containing silane compound or a hydrolyzable organosilicon compound to form a silica protective film. The thickness of the silica protective film may be 0.5 to 15 nm. Even if the silica protective film is formed, the protective film in this step is porous and thin, so that it is possible to remove inorganic compounds other than silica described above from the porous particle precursor.

  By forming such a silica protective film, inorganic compounds other than silica described above can be removed from the porous particle precursor while maintaining the particle shape. Further, when forming the silica coating layer described later, the pores of the porous particles are not blocked by the coating layer, and therefore the silica coating layer described later is formed without reducing the pore volume. Can do. Note that when the amount of the inorganic compound to be removed is small, the particles are not broken, and thus it is not always necessary to form a protective film.

  When preparing hollow particles, it is desirable to form this silica protective film. When preparing the hollow particles, the inorganic compound is removed to obtain a hollow particle precursor composed of a silica protective film, a solvent in the silica protective film, and an undissolved porous solid content. When a coating layer to be described later is formed on the precursor, the formed coating layer becomes a particle wall to form hollow particles.

The amount of the silica source added for forming the silica protective film is preferably small as long as the particle shape can be maintained. If the amount of the silica source is too large, the silica protective film becomes too thick, and it may be difficult to remove inorganic compounds other than silica from the porous particle precursor. The hydrolyzable organic silicon compound used for the silica protective film formed of the general formula _{R n Si (OR ') 4} -n [R, R': an alkyl group, an aryl group, a vinyl group, such as acrylic group An alkoxysilane represented by a hydrocarbon group, n = 0, 1, 2, or 3] can be used. In particular, tetraalkoxysilanes such as fluorine-substituted tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

  As an addition method, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilane, pure water, and alcohol is added to the dispersion of the porous particles, and the alkoxysilane is hydrolyzed. The produced silicic acid polymer is deposited on the surface of the inorganic oxide particles. At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

  When the dispersion medium of the porous particle precursor is water alone or when the ratio of water to the organic solvent is high, a silica protective film can be formed using a silicic acid solution. When a silicic acid solution is used, a predetermined amount of the silicic acid solution is added to the dispersion, and at the same time an alkali is added to deposit the silicic acid solution on the surface of the porous particles. In addition, you may produce a silica protective film together using a silicic acid liquid and the said alkoxysilane.

Third step: Formation of silica coating layer In the third step, the porous particle dispersion prepared in the second step (in the case of hollow particles, the hollow particle precursor dispersion) contains a fluorine-substituted alkyl group-containing silane compound. By adding a hydrolyzable organosilicon compound or silicic acid solution, the surface of the particles is coated with a polymer such as a hydrolyzable organosilicon compound or silicic acid solution to form a silica coating layer.

The hydrolyzable organic silicon compound used for the silica coating layer formed, the above-mentioned such general formula _{R n Si (OR ') 4} -n [R, R': an alkyl group, an aryl group, a vinyl group, An alkoxysilane represented by a hydrocarbon group such as an acryl group, n = 0, 1, 2, or 3] can be used. In particular, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

As an addition method, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilane, pure water, and alcohol is used as a dispersion of the porous particles (in the case of hollow particles, a hollow particle precursor). In addition, the silicic acid polymer produced by hydrolyzing alkoxysilane is deposited on the surface of the porous particles (in the case of hollow particles, hollow particle precursors). At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

  When the dispersion medium of porous particles (in the case of hollow particles, the hollow particle precursor) is water alone or a mixed solvent with an organic solvent and the mixed solvent has a high ratio of water to the organic solvent, a silicate solution You may form a coating layer using. The silicic acid solution is an aqueous solution of a low silicic acid polymer obtained by dealkalizing an aqueous solution of an alkali metal silicate such as water glass by ion exchange treatment.

  The silicic acid solution is added to the dispersion of porous particles (in the case of hollow particles, hollow particle precursors), and at the same time, alkali is added to make the low-silicic acid polymer into porous particles (in the case of hollow particles, hollow particle precursors). ) Deposit on the surface. In addition, you may use a silicic acid liquid for the coating layer formation in combination with the said alkoxysilane. The addition amount of the organosilicon compound or silicic acid solution used for forming the coating layer only needs to be sufficient to cover the surface of the colloidal particles, and the finally obtained silica coating layer has a thickness of 1 to 20 nm. In such an amount, it is added in a dispersion of porous particles (in the case of hollow particles, hollow particle precursor) in a dispersion. When the silica protective film is formed, the organosilicon compound or the silicate solution is added in such an amount that the total thickness of the silica protective film and the silica coating layer is in the range of 1 to 20 nm.

  Next, the dispersion liquid of the particles on which the coating layer is formed is heat-treated. By the heat treatment, in the case of porous particles, the silica coating layer covering the surface of the porous particles is densified, and a dispersion of composite particles in which the porous particles are coated with the silica coating layer is obtained. In the case of a hollow particle precursor, the formed coating layer is densified to form hollow particle walls, and a dispersion of hollow particles having cavities filled with a solvent, gas, or porous solid content is obtained.

  The heat treatment temperature at this time is not particularly limited as long as it can close the fine pores of the silica coating layer, and is preferably in the range of 80 to 300 ° C. When the heat treatment temperature is less than 80 ° C., the fine pores of the silica coating layer may not be completely closed and densified, and the treatment time may take a long time. Further, when the heat treatment temperature exceeds 300 ° C. for a long time, fine particles may be formed, and the effect of lowering the refractive index may not be obtained.

  The refractive index of the inorganic fine particles thus obtained is as low as less than 1.42. Such inorganic fine particles are presumed to have a low refractive index because the porosity inside the porous particles is maintained or the inside is hollow.

  The content of hollow fine particles having a porous or hollow interior in the low refractive index layer is preferably 10 to 40% by mass. In order to obtain the effect of lowering the refractive index, the content is preferably 15% by mass or more, and when it exceeds 40% by mass, the binder component is decreased and the film strength becomes insufficient. Most preferably, it is 20-40 mass%.

(Colloidal silica)
The colloidal silica used in the present invention is obtained by dispersing silicon dioxide in a colloidal form in water or an organic solvent, and is spherical, acicular or beaded. The average particle size of the colloidal silica needs to be 1.1 to less than 20 times the average particle size of the hollow fine particles, and preferably 1.5 to 5.0 times. Therefore, the average particle diameter of colloidal silica is preferably in the range of 50 to 300 nm. The particle size of colloidal silica is preferably monodispersed with a coefficient of variation of 1 to 40%. The average particle diameter can be measured from an electron micrograph taken with a scanning electron microscope (SEM) or the like. You may measure by the particle size distribution meter etc. which utilize a dynamic light scattering method, a static light scattering method, etc. However, when the ratio between the average particle size of colloidal silica and the average particle size of the hollow fine particles is obtained, the same measurement method must be used.

  Such colloidal silica used in the present invention is commercially available, and examples thereof include the Snowtex series of Nissan Chemical Industries, the Cataloid-S series of Catalytic Chemical Industry, and the Rebacil series of Bayer. Also, beaded colloidal silica in which primary particles of cation-modified with alumina sol or aluminum hydroxide are bonded in a bead shape by bonding the particles with divalent or higher metal ions. There are beaded colloidal silicas such as SNOWTEX-AK series, SNOWTEX-PS series, SNOWTEX-UP series of Nissan Chemical Industries.

  The content of the colloidal silica in the low refractive index layer is preferably 30 to 60% by mass with respect to the solid content in the low refractive index layer. In order to obtain the effect of lowering the refractive index, it is preferably 30% by mass or more, and when it exceeds 40% by mass, the binder component is decreased and the film strength becomes insufficient.

  The content ratio between the hollow fine particles and the colloidal silica in the low refractive index layer is selected from the viewpoint of the reflectance reduction effect and the surface hardness, but is preferably 1: 0.1 to 10, more preferably 1: 0.8 to 5. preferable.

(binder)
The low refractive index layer preferably contains 5 to 80% by mass of binder as a whole. The binder has a function of adhering silica fine particles and maintaining the structure of the low refractive index layer including voids. The usage-amount of a binder is adjusted so that the intensity | strength of a low refractive index layer can be maintained, without filling a space | gap. Examples of the binder include an organosilicon compound represented by the following general formula (1), a hydrolyzate thereof, or a polycondensate thereof.

General formula (1) Si (OR) ₄
In formula, R is an alkyl group, Preferably it is a C1-C4 alkyl group. As specific compound compounds, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used.

  The low refractive index layer may contain a silane coupling agent as a binder. Silane coupling agents include methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane. Ethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltri Acetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltri Ethoxysilane, γ- (β-glycidyloxyethoxy) propyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ- Acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, N- Examples include β- (aminoethyl) -γ-aminopropyltrimethoxysilane and β-cyanoethyltriethoxysilane.

  Examples of silane coupling agents having a disubstituted alkyl group with respect to silicon include dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, and γ-glycidyloxypropylmethyldiethoxysilane. Γ-glycidyloxypropylmethyldimethoxysilane, γ-glycidyloxypropylphenyldiethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldi Ethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimeth Shishiran, .gamma.-mercaptopropyl methyl diethoxy silane, .gamma.-aminopropyl methyl dimethoxy silane, .gamma.-aminopropyl methyl diethoxy silane, methyl vinyl dimethoxy silane, and methyl vinyl diethoxy silane.

  Among these, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane having a double bond in the molecule. Γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, and γ-methacryloyloxypropylmethyldiethoxy having a disubstituted alkyl group with respect to silicon Silane, methylvinyldimethoxysilane and methylvinyldiethoxysilane are preferred, and γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxyp Particularly preferred are propyltrimethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane and γ-methacryloyloxypropylmethyldiethoxysilane.

  Two or more coupling agents may be used in combination. In addition to the silane coupling agents shown above, other silane coupling agents may be used. Other silane coupling agents include alkyl esters of orthosilicate (eg, methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, i-propyl orthosilicate, n-butyl orthosilicate, sec-butyl orthosilicate, orthosilicate). Acid t-butyl) and its hydrolyzate.

  Examples of other binders for the low refractive index layer include polyvinyl alcohol, polyoxyethylene, polymethyl methacrylate, polymethyl acrylate, diacetyl cellulose, triacetyl cellulose, nitrocellulose, polyester, and alkyd resin.

(solvent)
The low refractive index layer coating composition according to the present invention preferably contains an organic solvent. Specific examples of organic solvents include alcohols (eg, methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), esters (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 Group hydrocarbon (eg, benzene, toluene, xylene), amide (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ether (eg, diethyl ether, dioxane, tetrahydrofuran), ether alcohol (eg, 1-methoxy-2-propanol). Of these, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol are particularly preferable.

  The solid content concentration in the low refractive index layer coating composition is preferably 1 to 4% by mass. By making the solid content concentration 4% by mass or less, coating unevenness is less likely to occur, and the content is 1% by mass or more. By doing so, the drying load is reduced.

(Fluorine or silicone surfactant)
The low refractive index layer preferably contains a fluorine-based or silicone-based surfactant. Inclusion of the surfactant is effective for reducing coating unevenness and improving the antifouling property of the film surface.

  Fluorosurfactants include perfluoroalkyl group-containing monomers, oligomers, and polymers as the core, and include derivatives such as polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, and polyoxyethylene. It is done.

  Commercially available products may be used as the fluorosurfactant, for example, Surflon “S-381”, “S-382”, “SC-101”, “SC-102”, “SC-103”, “SC-104”. (All manufactured by Asahi Glass Co., Ltd.), Florard “FC-430”, “FC-431”, “FC-173” (all manufactured by Fluorochemical-Sumitomo 3M), Ftop “EF352”, “EF301”, “EF303” (both manufactured by Shin-Akita Kasei Co., Ltd.), Schwego Fluer “8035”, “8036” (both manufactured by Schwegman), “BM1000”, “BM1100” (all manufactured by BM Himmy) , MegaFuck “F-171”, “F-470” (both manufactured by Dainippon Ink & Chemicals, Inc.), and the like.

  The fluorine content of the fluorosurfactant in the present invention is 0.05 to 2% by mass, preferably 0.1 to 1% by mass. The above-mentioned fluorosurfactants can be used alone or in combination of two or more, and can be used in combination with other surfactants.

  The silicone oil or silicone surfactant will be described.

  Silicone oils used in the present invention can be broadly classified into straight silicone oils and modified silicone oils depending on the type of organic groups bonded to silicon atoms. Straight silicone oil refers to those bonded with a methyl group, a phenyl group, or a hydrogen atom as a substituent. A modified silicone oil is one having a component that is secondarily derived from a straight silicone oil. On the other hand, it can be classified from the reactivity of silicone oil. These are summarized as follows.

Silicone oil Straight silicone oil 1-1. Non-reactive silicone oil: dimethyl, methylphenyl substitution, etc. 1-2. Reactive silicone oil: methyl hydrogen substitution, etc. Modified silicone oil Modified silicone oil was born by introducing various organic groups into dimethyl silicone oil 2-1. Non-reactive silicone oil: alkyl, alkyl / aralkyl, alkyl / polyether, polyether, higher fatty acid ester substitution, etc.
Alkyl / aralkyl-modified silicone oil is a silicone oil in which a part of methyl group of dimethyl silicone oil is replaced with a long-chain alkyl group or a phenylalkyl group,
Polyether-modified silicone oil is a silicone-based polymer surfactant in which hydrophilic polyoxyalkylene is introduced into hydrophobic dimethyl silicone,
Higher fatty acid-modified silicone oil is a silicone oil in which a part of methyl group of dimethyl silicone oil is replaced with higher fatty acid ester,
Amino-modified silicone oil is a silicone oil having a structure in which a part of methyl group of silicone oil is substituted with aminoalkyl group,
The epoxy-modified silicone oil is a silicone oil having a structure in which a part of the methyl group of the silicone oil is replaced with an epoxy group-containing alkyl group,
The carboxyl-modified or alcohol-modified silicone oil is a silicone oil having a structure in which a part of the methyl group of the silicone oil is substituted with a carboxyl group or a hydroxyl group-containing alkyl group 2-2. Reactive silicone oil: amino, epoxy, carboxyl, alcohol substitution, etc. Of these, polyether-modified silicone oil is preferably added. The number average molecular weight of the polyether-modified silicone oil is, for example, 1,000 to 100,000, preferably 2,000 to 50,000. When the number average molecular weight is less than 1,000, the drying property of the coating film On the contrary, when the number average molecular weight exceeds 100,000, it tends to be difficult to bleed out on the surface of the coating film.

  Specific products include L-45, L-9300, FZ-3704, FZ-3703, FZ-3720, FZ-3786, FZ-3501, FZ-3504, FZ-3508, FZ of Nippon Unicar Co., Ltd. -3705, FZ-3707, FZ-3710, FZ-3750, FZ-3760, FZ-3785, FZ-3785, Y-7499, Shin-Etsu Chemical KF96L, KF96, KF96H, KF99, KF54, KF965, KF968, KF56 KF995, KF351, KF352, KF353, KF354, KF355, KF615, KF618, KF945, KF6004, FL100 and the like.

  The silicone surfactant used in the present invention is a surfactant obtained by substituting a part of the methyl group of the silicone oil with a hydrophilic group. The position of substitution includes a side chain of silicone oil, both ends, one end, both end side chains, and the like. Examples of the hydrophilic group include polyether, polyglycerin, pyrrolidone, betaine, sulfate, phosphate, and quaternary salt.

  As the silicone surfactant, a nonionic surfactant having a hydrophobic group composed of dimethylpolysiloxane and a hydrophilic group composed of polyoxyalkylene is preferable.

  A nonionic surfactant is a generic term for surfactants that do not have a group capable of dissociating into ions in an aqueous solution. In addition to a hydrophobic group, a hydrophilic group includes a hydroxyl group of a polyhydric alcohol, a polyoxyalkylene chain (poly Oxyethylene) or the like as a hydrophilic group. The hydrophilicity becomes stronger as the number of alcoholic hydroxyl groups increases and as the polyoxyalkylene chain (polyoxyethylene chain) becomes longer. The nonionic surfactant according to the present invention is characterized by having dimethylpolysiloxane as a hydrophobic group.

  When a nonionic surfactant composed of a dimethylpolysiloxane having a hydrophobic group and a polyoxyalkylene having a hydrophilic group is used, the unevenness of the low refractive index layer and the antifouling property of the film surface are improved. It is thought that the hydrophobic group made of polymethylsiloxane is oriented on the surface and forms a film surface that is not easily soiled. This effect cannot be obtained by using other surfactants.

  Specific examples of these nonionic surfactants include, for example, Nippon Unicar Co., Ltd., silicone surfactants SILWET L-77, L-720, L-7001, L-7002, L-7604, Y-7006, FZ-2101, FZ-2104, FZ-2105, FZ-2110, FZ-2118, FZ-2120, FZ-2122, FZ-2123, FZ-2130, FZ-2154, FZ-2161, FZ-2162, FZ- 2163, FZ-2164, FZ-2166, FZ-2191 and the like.

  Moreover, SUPERSILWET SS-2801, SS-2802, SS-2803, SS-2804, SS-2805, etc. are mentioned.

  Further, as a preferable structure of the nonionic surfactant in which the hydrophobic group is composed of dimethylpolysiloxane and the hydrophilic group is composed of polyoxyalkylene, the dimethylpolysiloxane structure portion and the polyoxyalkylene chain are alternately and repeatedly bonded. It is preferably a linear block copolymer. Since the main chain skeleton has a long chain length and a linear structure, it is excellent. This is considered to be due to the fact that one activator molecule can be adsorbed on the surface of the silica fine particle at a plurality of locations so as to cover the surface of the silica fine particle by being a block copolymer in which hydrophilic groups and hydrophobic groups are alternately repeated.

  Specific examples include silicone surfactants ABN SILWET FZ-2203, FZ-2207, FZ-2208, and FZ-2222 manufactured by Nippon Unicar Co., Ltd.

  Among these silicone oils or silicone surfactants, those having a polyether group are preferred.

  Further, surfactant BYK series, BYK-300 / 302, BYK-306, BYK-307, BYK-310, BYK-315, BYK-320, BYK-322, BYK-323, manufactured by BYK Japan 325, BYK-330, BYK-331, BYK-333, BYK-337, BYK-340, BYK-344, BYK-370, BYK-375, BYK-377, BYK-352, BYK-354, BYK-355 / 356, BYK-358N / 361N, BYK-357, BYK-390, BYK-392, BYK-UV3500, BYK-UV3510, BYK-UV3570, BYK-Silclean3700, dimethyl silicone series manufactured by GE Toshiba Silicone, XC96-723, YF380 , It can be preferably used XF3905, YF3057, YF3807, YF3802, YF3897.

  Other surfactants may also be used in combination. For example, anionic surfactants such as sulfonates, sulfates, phosphates, etc., and ethers having polyoxyethylene chain hydrophilic groups Type, ether ester type nonionic surfactants and the like may be used in combination.

  In the present invention, these silicone oils or silicone surfactants are preferably used in the low refractive index layer and the layer adjacent to the low refractive index layer, specifically, the hard coat layer and the high refractive index layer. When the low refractive index layer is the outermost surface layer of the antireflection film, it not only improves the water repellency, oil repellency and antifouling properties of the coating film, but also exhibits an effect on the scratch resistance of the surface. The content in the low refractive index layer coating solution is preferably 0.05 to 2.0% by mass. If it is less than 0.05% by mass, the crack resistance effect is insufficient, and if it exceeds 2.0% by mass, uneven coating may occur.

(acid)
In the present invention, by adding an acid to the low refractive index layer coating composition, alkaline components such as ammonia are eluted from the inside of the hollow fine particles, and the coating layer of the low refractive index layer is coated after the coating solution is prepared and applied. It can also prevent the viscosity from increasing.

  Examples of the acid to be added include known inorganic acids and organic acids. In the present invention, organic acids are preferable. Examples of the organic acid include acetic acid, formic acid, propionic acid, etc. Among them, acetic acid is preferable. The addition amount of the organic acid is an amount corresponding to an alkali component such as ammonia from the inside of the hollow fine particles, and an acid, for example, acetic acid, for example, 5 to 100 mass% is added to the solid content in the hollow fine particle dispersion. Depending on the concentration of the hollow fine particle dispersion, it is usually preferable to add the acid in the range of 0.5 to 30.0% by mass of the hollow fine particle dispersion.

(High refractive index layer)
Various functional layers can be provided between the transparent support and the low refractive index layer. A typical example of the high refractive index layer will be described.

(Metal oxide fine particles of high refractive index layer)
The high refractive index layer preferably contains metal oxide fine particles. The kind of metal oxide fine particles is not particularly limited, and Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P and S A metal oxide having at least one element selected from the group consisting of Al, In, Sn, Sb, Nb, a halogen element, Ta and the like is doped with a trace amount of atoms. May be. A mixture of these may also be used. In the present invention, at least one metal oxide fine particle selected from among zirconium oxide, antimony oxide, tin oxide, zinc oxide, indium-tin oxide (ITO), antimony-doped tin oxide (ATO), and zinc antimonate is used. It is preferably used as a main component, particularly preferably zinc antimonate.

  The average particle size of primary particles of these metal oxide fine particles is preferably 10 to 200 nm, more preferably 10 to 150 nm. The average particle diameter of the metal oxide fine particles can be measured from an electron micrograph taken with a scanning electron microscope (SEM) or the like. You may measure by the particle size distribution meter etc. which utilize a dynamic light scattering method, a static light scattering method, etc. If the particle size is too small, aggregation tends to occur and the dispersibility deteriorates. If the particle size is too large, the haze is remarkably increased. The shape of the metal oxide fine particles is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape, a needle shape, or an indefinite shape.

  Specifically, the refractive index of the high refractive index layer is higher than the refractive index of the transparent support that is the support, and is preferably in the range of 1.50 to 1.90 when measured at 23 ° C. and a wavelength of 550 nm. As a means for adjusting the refractive index of the high refractive index layer, the kind and addition amount of the metal oxide fine particles are dominant, and therefore the refractive index of the metal oxide fine particles is preferably 1.80 to 2.60.

  The metal oxide fine particles may be surface-treated with an organic compound. By modifying the surface of the metal oxide fine particles with an organic compound, the dispersion stability in an organic solvent is improved, the dispersion particle size can be easily controlled, and aggregation and sedimentation over time can be suppressed. . For this reason, the surface modification amount with a preferable organic compound is 0.1-5 mass% with respect to metal oxide particle, More preferably, it is 0.5-3 mass%. Examples of the organic compound used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents, and titanate coupling agents. Among these, the silane coupling agent mentioned later is preferable. Two or more kinds of surface treatments may be combined.

  The thickness of the high refractive index layer containing the metal oxide fine particles is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm.

  The ratio of the metal oxide fine particles to be used and a binder such as an ionizing radiation curable resin, which will be described later, varies depending on the type and particle size of the metal oxide fine particles, but the volume ratio of the former 1 to the latter 2 to the former 2 The latter one is preferable.

  The amount of the metal oxide fine particles used in the present invention is preferably 5 to 85% by mass, more preferably 10 to 80% by mass, and still more preferably 20 to 75% by mass in the high refractive index layer. If the amount used is small, the desired refractive index and the effect of the present invention cannot be obtained, and if it is too large, the film strength is deteriorated.

  The metal oxide fine particles are supplied to a coating solution for forming a high refractive index layer in a dispersion state dispersed in a medium. As a dispersion medium for metal oxide particles, it is preferable to use a liquid having a boiling point of 60 to 170 ° C. Specific examples of the dispersion solvent include water, alcohol (eg, methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketone (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), ketone alcohol (eg, diacetone alcohol). , Esters (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 hydrocarbons (eg, benzene, toluene, xylene), amides (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ethers (eg, diethyl ether, dioxane, Tiger hydrofuran), ether alcohols (e.g., 1-methoxy-2-propanol). Of these, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol are particularly preferable.

  The metal oxide fine particles can be dispersed in the medium using a disperser. Examples of the disperser include a sand grinder mill (eg, a bead mill with pins), a high-speed impeller mill, a pebble mill, a roller mill, an attritor, and a colloid mill. 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.

  In the present invention, metal oxide fine particles having a core / shell structure may be further contained. One layer of the shell may be formed around the core, or a plurality of layers may be formed in order to further improve the light resistance. The core is preferably completely covered by the shell.

  As the core, titanium oxide (rutile type, anatase type, amorphous type, etc.), zirconium oxide, zinc oxide, cerium oxide, indium oxide doped with tin, tin oxide doped with antimony, or the like can be used.

  The shell is preferably formed of a metal oxide or sulfide containing an inorganic compound other than titanium oxide as a main component. For example, an inorganic compound mainly composed of silicon dioxide (silica), aluminum oxide (alumina) zirconium oxide, zinc oxide, tin oxide, antimony oxide, indium oxide, iron oxide, zinc sulfide, or the like is used. Of these, alumina, silica, and zirconia (zirconium oxide) are preferable. A mixture of these may also be used.

  The coating amount of the shell with respect to the core is 2 to 50% by mass as an average coating amount. Preferably it is 3-40 mass%, More preferably, it is 4-25 mass%. When the coating amount of the shell is large, the refractive index of the fine particles is lowered, and when the coating amount is too small, the light resistance is deteriorated. Two or more inorganic fine particles may be used in combination.

  The titanium oxide used as a core can use what was produced by the liquid phase method or the gaseous-phase method. As a method for forming the shell around the core, for example, U.S. Pat. No. 3,410,708, JP-B-58-47061, U.S. Pat. No. 2,885,366, and U.S. Pat. No. 1, British Patent No. 1,134,249, US Pat. No. 3,383,231, British Patent No. 2,629,953, No. 1,365,999, etc. Can do.

(Ionizing radiation curable resin)
The ionizing radiation curable resin is added as a binder for the metal oxide fine particles to improve the film formability and physical properties of the coating film. As the ionizing radiation curable resin, a monomer or oligomer having two or more functional groups that cause polymerization reaction directly by irradiation of ionizing radiation such as ultraviolet rays or electron beams or indirectly by the action of a photopolymerization initiator is used. Can be used. Examples of the functional group include a group having an unsaturated double bond such as a (meth) acryloyloxy group, an epoxy group, and a silanol group. Among these, radically polymerizable monomers and oligomers having two or more unsaturated double bonds can be preferably used. You may combine a photoinitiator as needed. Examples of such ionizing radiation curable resins include polyfunctional acrylate compounds and the like, and the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. It is preferable that it is a compound chosen from these. Here, the polyfunctional acrylate compound is a compound having two or more acryloyloxy groups and / or methacryloyloxy groups in the molecule.

  Examples of the monomer of the polyfunctional acrylate compound include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethanetriacrylate. Acrylate, tetramethylol methane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, glycerin triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, Dipen Erythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetra Methylol methane trimethacrylate, tetramethylol methane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerin trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol te La methacrylate, dipentaerythritol penta methacrylate, dipentaerythritol hexa methacrylate preferred. These compounds are used alone or in admixture of two or more. Moreover, oligomers, such as a dimer and a trimer of the said monomer, may be sufficient.

  The addition amount of the ionizing radiation curable resin is preferably 15% by mass or more and less than 50% by mass in the solid content in the high refractive index composition.

  In order to accelerate the curing of the ionizing radiation curable resin, a photopolymerization initiator and an acrylic compound having two or more polymerizable unsaturated bonds in the molecule may be contained in a mass ratio of 3: 7 to 1: 9. preferable.

  Specific examples of the photopolymerization initiator include acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto.

(solvent)
Examples of the organic solvent used for coating the high refractive index layer include alcohols (for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol). , Benzyl alcohol, etc.), polyhydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thio Diglycol, etc.), polyhydric alcohol ethers (eg, ethylene glycol monomethyl ether, Lenglycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl Ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.), amines (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ether) Range amine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.), amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.) ), Heterocyclic rings (for example, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone), sulfoxides (for example, dimethyl sulfoxide) , Sulfones (e.g., sulfolane), urea, acetonitrile, acetone and the like, and alcohols, polyhydric alcohols, and polyhydric alcohol ethers are particularly preferable.

[Hard coat layer]
In the antireflection film of the present invention, a hard coat layer is preferably provided between the transparent support and an antireflection layer such as a high refractive index layer or a low refractive index layer. The hard coat layer is preferably an active energy ray curable resin layer.

  The active energy ray-curable resin layer refers to a layer mainly composed of a resin that is cured through a crosslinking reaction or the like by irradiation with active rays such as ultraviolet rays or electron beams. As the active energy ray curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the active energy ray curable resin layer is cured by irradiation with an active ray such as an ultraviolet ray or an electron beam. It is formed. Typical examples of the active energy ray curable resin include an ultraviolet curable resin and an electron beam curable resin, and a resin curable by ultraviolet irradiation is preferable.

  As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable epoxy resin is preferable. Used. Of these, ultraviolet curable acrylate resins are preferred.

  The UV curable acrylic urethane resin generally includes 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as acrylate) in addition to a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer. It can be easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate. For example, those described in JP-A-59-151110 can be used.

  For example, a mixture of 100 parts Unidic 17-806 (Dainippon Ink Chemical Co., Ltd.) and 1 part Coronate L (Nihon Polyurethane Co., Ltd.) is preferably used.

  Examples of UV curable polyester acrylate resins include those which are easily formed when 2-hydroxyethyl acrylate and 2-hydroxy acrylate monomers are generally reacted with polyester polyols. JP-A-59-151112 Can be used.

  Specific examples of the ultraviolet curable epoxy acrylate resin include an epoxy acrylate as an oligomer, a reactive diluent and a photopolymerization initiator added thereto, and reacted to form an oligomer. Those described in US Pat. No. 105738 can be used.

  Specific examples of UV curable polyol acrylate resins include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, etc. Can be mentioned.

  Specific examples of photopolymerization initiators for these ultraviolet curable resins include benzoin and its derivatives, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof. You may use with a photosensitizer. The photopolymerization initiator can also be used as a photosensitizer. In addition, when using an epoxy acrylate photopolymerization initiator, a sensitizer such as n-butylamine, triethylamine, tri-n-butylphosphine can be used. The photopolymerization initiator or photosensitizer used in the ultraviolet curable resin composition is 0.1 to 15 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the composition.

  Examples of the resin monomer may include general monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, vinyl acetate, and styrene as monomers having one unsaturated double bond. In addition, monomers having two or more unsaturated double bonds include ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane diacrylate, 1,4-cyclohexyldimethyl adiacrylate, and the above trimethylolpropane. Examples thereof include triacrylate and pentaerythritol tetraacryl ester.

Examples of commercially available ultraviolet curable resins that can be used in the present invention include ADEKA OPTMER KR / BY series: KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (Asahi Denka ( Co., Ltd.); Koeihard A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T-102, D-102, NS -101, FT-102Q8, MAG-1-P20, AG-106, M-101-C (manufactured by Guangei Chemical Co., Ltd.); Seika Beam PHC2210 (S), PHC X-9 (K-3), PHC2213, DP -10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (manufactured by Dainichi Seika Kogyo Co., Ltd.) KRM7033, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202 (manufactured by Daicel UCB); RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC-5102, RC-5120 , RC-5122, RC-51
52, RC-5171, RC-5180, RC-5181 (Dainippon Ink Chemical Co., Ltd.); 340 clear (manufactured by China Paint Co., Ltd.); Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (manufactured by Sanyo Chemical Industries); SP -1509, SP-1507 (manufactured by Showa Polymer Co., Ltd.); RCC-15C (manufactured by Grace Japan Co., Ltd.), Aronix M-6100, M-8030, M-8060 (manufactured by Toagosei Co., Ltd.); NK hardware B-420, B-500 (manufactured by Shin-Nakamura Chemical Co., Ltd.) and the like can be appropriately selected and used.

  Examples of specific compounds include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, and the like. .

  The cured resin layer thus obtained may contain fine particles of an inorganic compound or an organic compound in order to adjust the scratch resistance, slipperiness and refractive index, and to impart antiglare properties to the produced antireflection film.

  Examples of inorganic fine particles used in the hard coat layer include silicon oxide, titanium oxide, aluminum oxide, tin oxide, indium oxide, ITO, zinc oxide, zirconium oxide, magnesium oxide, calcium carbonate, calcium carbonate, talc, clay, and calcined kaolin. And calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. In particular, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide and the like are preferably used.

  Organic particles include polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, silicone resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine resin powder, and melamine resin powder. Polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, or polyfluoroethylene resin powder can be added to the ultraviolet curable resin composition. Particularly preferred are cross-linked polystyrene particles (for example, SX-130H, SX-200H, SX-350H, manufactured by Soken Chemical) and polymethyl methacrylate-based particles (for example, MX150, MX300, manufactured by Soken Chemical).

  The average particle size of these fine particle powders is preferably 0.01 to 5 μm, more preferably 0.1 to 5.0 μm, and particularly preferably 0.1 to 4.0 μm. Moreover, it is preferable to contain 2 or more types of microparticles | fine-particles from which a particle size differs. The proportion of the ultraviolet curable resin composition and the fine particles is desirably blended so as to be 0.1 to 30 parts by mass with respect to 100 parts by mass of the resin composition.

  These hard coat layers can be coated by a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, or an ink jet method. After application, it is heat-dried and UV-cured.

As a light source for curing an ultraviolet curable resin by a photocuring reaction to form a cured film layer, any light source that generates ultraviolet rays can be used without limitation. 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. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 150 mJ / cm ² , and particularly preferably 20 to 100 mJ / cm ² .

  Moreover, when irradiating actinic radiation, it is preferable to carry out while applying tension | tensile_strength in the conveyance direction of a film, More preferably, it is performing applying tension | tensile_strength also in the width direction. The tension to be applied is preferably 30 to 300 N / m. The method for applying tension is not particularly limited, and tension may be applied in the transport direction on the back roll, or tension may be applied in the width direction or biaxial direction by a tenter. This makes it possible to obtain a film having further excellent flatness.

  The hard coat layer coating solution may contain a solvent, or may be appropriately contained and diluted as necessary. Examples of the organic solvent contained in the coating liquid include hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone), These may be appropriately selected from esters (methyl acetate, ethyl acetate, methyl lactate), glycol ethers, and other organic solvents, or may be used by mixing them. Propylene glycol monoalkyl ether (1 to 4 carbon atoms of the alkyl group) or propylene glycol monoalkyl ether acetate ester (1 to 4 carbon atoms of the alkyl group) is 5% by mass or more, more preferably 5 to 80%. It is preferable to use the organic solvent containing at least mass%.

(Anti-glare)
The antireflection film of the present invention is preferably antiglare. The anti-glare property reduces the visibility of the reflected image by blurring the outline of the image reflected on the surface, and the reflected image is reflected when using an image display device such as a liquid crystal display, an organic EL display, or a plasma display. It's something you don't mind. By providing appropriate unevenness on the surface, such a property can be provided.

  As a method for forming such irregularities, processing to a transparent support, processing to a hard coat layer, processing to an antireflection film after applying an antireflection layer, etc. can be selected. In the present invention, since the projections of the concavo-convex shape may break through the antireflection layer or deform the antireflection layer to impair the antireflection effect, in the present invention, processing to a transparent support, processing to a hard coat layer Is preferred.

  Examples of the concavo-convex shape referred to in the present invention include structures selected from right cones, oblique cones, pyramids, oblique pyramids, wedge shapes, convex polygons, hemispheres, and the like, and structures having these partial shapes. Note that the hemispherical shape does not necessarily have a true spherical shape, and may be an ellipsoidal shape or a more deformed convex curved shape. Moreover, the prism shape, the lenticular lens shape, and the Fresnel lens shape in which the ridge line of the concavo-convex shape extends linearly can also be mentioned. The slope from the ridge line to the valley line may be flat, curved, or a combination of both.

  The hard coat layer is preferably an antiglare hard coat layer having an arithmetic average roughness (Ra) defined by JIS B 0601: 2001 of 60 to 700 nm, preferably 80 to 400 nm. When Ra is less than 60 nm, the antiglare effect is weak, and when it exceeds 700 nm, an impression that is too coarse is visually observed. The arithmetic average roughness (Ra) is preferably measured with an optical interference type surface roughness measuring instrument, and can be measured using, for example, an optical interference type surface roughness meter RST / PLUS (manufactured by WYKO).

Examples of a method for forming a concavo-convex shape on the surface of the hard coat layer and the transparent support described later include the following methods.
(1) A method in which a negative shape having a desired shape is formed on a roll or master, and the shape is given by embossing.
(2) A method in which a negative mold having a desired shape is formed on a roll or a master, a thermosetting resin is filled into the negative mold, and the film is peeled off from the negative mold after heat curing.
(3) A negative shape of a desired shape is formed on a roll or a master, and after applying ultraviolet rays or electron beam curable resin and filling the concave portions, ultraviolet rays are applied while the transparent support is coated on the intaglio via a resin liquid. Alternatively, a method in which the cured resin and the transparent support to which it is adhered are peeled from the negative mold by irradiation with an electron beam.
(4) A solvent casting method in which a negative shape having a desired shape is formed on a casting belt and the desired shape is imparted during casting.
(5) A method in which a resin that is cured by light or heating is relief-printed on a transparent substrate and is cured by light or heating to form irregularities.
(6) A method in which a resin that is cured by light or heating is printed on the surface of the transparent support by an ink jet method, and the surface of the transparent support is made uneven by curing by light or heating.
(7) A method of cutting the surface with a machine tool or the like.
(8) A method in which particles of various shapes such as spheres and polygons are pressed and integrated so as to be partially buried in the surface of the transparent support to make the surface of the transparent support uneven.
(9) A method in which particles of various shapes such as spheres and polygons dispersed in a small amount of binder are applied to the surface of the transparent support to make the surface of the transparent support uneven.
(10) A method in which a binder is applied to the surface of the transparent support, and particles of various shapes such as spheres and polygons are dispersed thereon to make the surface of the transparent support uneven.

  In order to make the hard coat layer antiglare, there is a method of adding the fine particles to the coating solution.

In the present invention, as the antiglare fine particles, for example, fluorine-containing acrylic resin fine particles are preferable in addition to the inorganic fine particles or organic fine particles. As the fluorine-containing acrylic resin fine particles, for example, a fluorine-containing acrylic ester or methacrylate ester monomer or Fine particles formed from a polymer.
Specific examples of the fluorine-containing acrylic ester or methacrylic ester include 1H, 1H, 3H-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 1H, 1H, 7H- Dodecafluoroheptyl (meth) acrylate, 1H, 1H, 9H-hexadecafluorononyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3,3-pentafluoropropyl (Meth) acrylate, 2- (perfluorobutyl) ethyl (meth) acrylate, 2- (perfluorohexyl) ethyl (meth) acrylate, 2- (perfluorooctyl) ethyl) (meth) acrylate, 2-perfluorodecyl Ethyl (meth) acrylate, 3-par Fluorobutyl-2-hydroxypropyl (meth) acrylate, 3-perfluorohexyl-2-hydroxypropyl (meth) acrylate, 3-perfluorooctyl-2-hydroxypropyl (meth) acrylate, 2- (perfluoro-3-methylbutyl) ) Ethyl (meth) acrylate, 2- (perfluoro-5-methylhexyl) ethyl (meth) acrylate, 2- (perfluoro-7-methyloctyl) ethyl (meth) acrylate, 3- (perfluoro-3-methylbutyl) 2-hydroxypropyl (meth) acrylate, 3- (perfluoro-5-methylhexyl) -2-hydroxypropyl (meth) acrylate, 3- (perfluoro-7-methyloctyl) -2-hydroxypropyl (meth) Acrylate, 1H-1- ( Trifluoromethyl) trifluoroethyl (meth) acrylate, 1H, 1H, 3H-hexafluorobutyl (meth) acrylate, trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, perfluorooctylethyl acrylate, 2- (perfluorobutyl) ethyl -Α-fluoroacrylate.

  Among the fluorine-containing acrylic resin fine particles, fine particles composed of 2- (perfluorobutyl) ethyl-α-fluoroacrylate, fluorine-containing polymethyl methacrylate fine particles, fluorine-containing methacrylic acid in the presence of a crosslinking agent, a vinyl monomer Fine particles copolymerized with fluorinated polymethyl methacrylate are more preferred.

The vinyl monomer copolymerizable with fluorine-containing (meth) acrylic acid is not particularly limited as long as it has a vinyl group. Specifically, alkyl methacrylates such as methyl methacrylate and butyl methacrylate, and methyl acrylate. , Alkyl acrylates such as ethyl acrylate, and styrenes such as styrene and α-methylstyrene. These may be used alone or in combination.
The crosslinking agent used in the polymerization reaction is not particularly limited, but those having two or more unsaturated groups are preferably used. For example, bifunctional dimethacrylates such as ethylene glycol dimethacrylate and polyethylene glycol dimethacrylate are used. And trimethylolpropane trimethacrylate, divinylbenzene and the like.

In the present invention, the polymerization reaction for producing the fluorine-containing polymethyl methacrylate fine particles may be either random copolymerization or block copolymerization.
Specifically, for example, the method described in JP-A No. 2000-169658 can be mentioned, and examples of commercially available products include commercially available products such as Nippon Paint: FS-701 and Negami Kogyo: MF-0043. Can be mentioned.
Note that these fluorine-containing acrylic resin fine particles may be used alone or in combination of two or more. Moreover, the state of these fluorine-containing acrylic resin fine particles may be added in any state such as powder or emulsion.
The average particle diameter of the fluorine-containing acrylic resin fine particle powder is preferably 0.01 to 5 μm, more preferably 0.1 to 5.0 μm, and particularly preferably 0.1 to 4.0 μm.
Further, it is preferable to contain two or more kinds of fine particles having different particle diameters. The proportion of the ultraviolet curable resin composition and the fine particles is desirably blended so as to be 0.1 to 30 parts by mass with respect to 100 parts by mass of the resin composition.

  Furthermore, it is also preferable that the hard coat layer contains the fluorine-based or silicone-based surfactant. These improve the applicability to the lower layer. These components are preferably added in a range of 0.01 to 3% by mass with respect to the solid component in the coating solution. Specific examples of the silicone-based surfactant include the surfactant BYK series manufactured by Big Chemie Japan Co., Ltd. described for the low refractive index layer.

  The hard coat layer has a multilayer structure of two or more layers, and one of the layers may be a so-called antistatic layer containing, for example, conductive fine particles or an ionic polymer. As a color correction filter for the element, a color tone adjusting agent having a color tone adjusting function may be contained, and it is preferable to contain an electromagnetic wave blocking agent or an infrared absorber so as to have each function.

  As the coating method of the hard coat layer coating solution, the above-described methods can be used. The coating amount is suitably 0.1 to 30 μm, preferably 0.5 to 15 μm, as the wet film thickness. Moreover, as a dry film thickness, it is an average film thickness of 0.1-15 micrometers, Preferably it is 1-8 micrometers.

  The hard coat layer is preferably irradiated with ultraviolet rays after coating and drying, and the irradiation time for obtaining the necessary amount of active ray irradiation is preferably about 0.1 second to 1 minute, and the curing efficiency of the ultraviolet curable resin Or from the viewpoint of work efficiency, 0.1 to 10 seconds is more preferable.

Moreover, it is preferable that the illuminance of these active ray irradiation parts is 50-150 mW / m < ² >.

[Back coat layer]
In the antireflection film of the present invention, it is preferable to provide a backcoat layer on the surface opposite to the side on which the active energy ray-curable resin layer of the cellulose ester film serving as the transparent support is provided. The back coat layer is provided in order to correct curl caused by providing an active energy ray-curable resin layer or other layers. That is, the degree of curling can be balanced by imparting the property of being rounded with the surface on which the backcoat layer is provided facing inward. The back coat layer is preferably applied also as an anti-blocking layer. In this case, it is preferable that fine particles are added to the back coat layer coating composition in order to provide an anti-blocking function.

  As fine particles added to the back coat layer, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, tin oxide, and oxidation. Mention may be made of indium, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Fine particles containing silicon are preferable in terms of low haze, and silicon dioxide is particularly preferable.

  These fine particles are commercially available under the trade names of, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 (manufactured by Nippon Aerosil Co., Ltd.). . Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used. Examples of the polymer include silicone resin, fluororesin, and acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large anti-blocking effect while keeping haze low. The antireflection film used in the present invention preferably has a dynamic friction coefficient on the back side of the active energy ray-curable resin layer of 0.9 or less, particularly 0.1 to 0.9.

  The fine particles contained in the backcoat layer are 0.1 to 50% by weight, preferably 0.1 to 10% by weight, based on the binder. When the back coat layer is provided, the increase in haze is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.0 to 0.1%.

  Specifically, the back coat layer is formed by applying a composition containing a solvent for dissolving or swelling a cellulose ester film. The solvent to be used may include a solvent to be dissolved and / or a solvent to be swollen in addition to a solvent to be dissolved, a composition in which these are mixed at an appropriate ratio depending on the curl degree of the transparent resin film and the type of the resin, and This is done using the coating amount.

  In order to enhance the curl prevention function, it is effective to increase the mixing ratio of the solvent for dissolving the solvent composition to be used and / or the solvent for swelling, and to decrease the ratio of the solvent not to be dissolved. This mixing ratio is preferably (solvent to be dissolved and / or solvent to be swollen) :( solvent to be dissolved) = 10: 0 to 1: 9. Examples of the solvent for dissolving or swelling the transparent resin film contained in such a mixed composition include dioxane, acetone, methyl ethyl ketone, N, N-dimethylformamide, methyl acetate, ethyl acetate, trichloroethylene, methylene chloride, and ethylene chloride. , Tetrachloroethane, trichloroethane, chloroform and the like. Examples of the solvent that does not dissolve include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butanol, cyclohexanol, and hydrocarbons (toluene, xylene).

  These coating compositions are preferably applied to the surface of the transparent resin film with a wet film thickness of 1 to 100 μm using a gravure coater, dip coater, reverse coater, wire bar coater, die coater, spray coating, ink jet coating or the like. Is particularly preferably 5 to 30 μm. Examples of the resin used as the binder of the backcoat layer include vinyl chloride-vinyl acetate copolymer, vinyl chloride resin, vinyl acetate resin, vinyl acetate-vinyl alcohol copolymer, partially hydrolyzed vinyl chloride-vinyl acetate copolymer. Polymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, ethylene-vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, etc. Vinyl polymer or copolymer, nitrocellulose, cellulose acetate propionate (preferably acetyl group substitution degree 1.8-2.3, propionyl group substitution degree 0.1-1.0), diacetyl cellulose, cellulose Cellulose derivatives such as acetate butyrate resin, maleic acid and / or Or acrylic acid copolymer, acrylic ester copolymer, acrylonitrile-styrene copolymer, chlorinated polyethylene, acrylonitrile-chlorinated polyethylene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, acrylic resin Rubber resins such as polyvinyl acetal resin, polyvinyl butyral resin, polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, polyether resin, polyamide resin, amino resin, styrene-butadiene resin, butadiene-acrylonitrile resin, Examples thereof include, but are not limited to, silicone resins and fluorine resins. For example, as an acrylic resin, Acrypet MD, VH, MF, V (manufactured by Mitsubishi Rayon Co., Ltd.), Hyperl M-4003, M-4005, M-4006, M-4202, M-5000, M-5001, M-4501 (manufactured by Negami Kogyo Co., Ltd.), Dialnal BR-50, BR-52, BR-53, BR-60, BR-64, BR-73, BR-75, BR-77, BR-79, BR -80, BR-82, BR-83, BR-85, BR-87, BR-88, BR-90, BR-93, BR-95, BR-100, BR-101, BR-102, BR-105 BR-106, BR-107, BR-108, BR-112, BR-113, BR-115, BR-116, BR-117, BR-118, etc. (Mitsubishi Rayon Co., Ltd.) acrylic and The methacrylic monomers are commercially available various homopolymers and copolymers, etc. was prepared as a raw material, it is also possible to select a preferred mono from this appropriate.

  Particularly preferred are cellulose resin layers such as diacetylcellulose and cellulose acetate propionate.

  The order of coating the backcoat layer may be before or after coating the active energy ray-curable resin layer of the cellulose ester film, but when the backcoat layer also serves as an antiblocking layer, it is desirable to coat it first. . Alternatively, the backcoat layer can be applied in two or more steps.

  The surfactant BYK series manufactured by Big Chemie Japan Co., Ltd. and the dimethyl silicone series manufactured by GE Toshiba Silicone Co., Ltd. described in the low refractive index layer can be preferably used for an antireflection layer other than the low refractive index layer.

(Transparent support)
Next, the transparent support that can be used in the present invention will be described.

  The transparent support used in the present invention is easy to manufacture, has good adhesion to the actinic radiation curable resin layer, is optically isotropic, is optically transparent, etc. Is a preferable requirement.

  The term “transparent” as used in the present invention means that the visible light transmittance is 60% or more, preferably 80% or more, and particularly preferably 90% or more.

  Although it will not specifically limit if it has said property, For example, a cellulose-ester type film, a polyester-type film, a polycarbonate-type film, a polyarylate-type film, a polysulfone (a polyether sulfone is also included) type film, a polyethylene terephthalate, polyethylene Polyester film such as naphthalate, polyethylene film, polypropylene film, cellophane, cellulose diacetate film, cellulose triacetate, cellulose acetate propionate film, cellulose acetate butyrate film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, Syndiotactic polystyrene film, polycarbonate film, cycloolefin Polymer film (Arton (manufactured by JSR), ZEONEX, ZEONOR (manufactured by ZEON CORPORATION)), polymethylpentene film, polyetherketone film, polyetherketoneimide film, polyamide film, fluororesin film, nylon film, poly A methyl methacrylate film, an acrylic film, a glass plate, etc. can be mentioned. Among them, cellulose triacetate film, polycarbonate film, and polysulfone (including polyethersulfone) are preferable, and in the present invention, cellulose ester film (for example, Konica Minoltack, product names KC8UX2MW, KC4UX2MW, KC8UY, KC4UNY, KC5UN, KC12UR, KC8UCR-3, KC8UCR-4, and KC8UCR-5 (manufactured by Konica Minolta Opto Co., Ltd.) are preferably used from the viewpoints of production, cost, transparency, isotropic properties, adhesiveness, and the like. These films may be films produced by melt casting film formation or films produced by solution casting film formation.

(Cellulose ester)
In the present invention, it is preferable to use a cellulose ester film as the transparent support. As the cellulose ester, cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate are preferable. Among them, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose acetate propionate are preferably used.

  In particular, when the substitution degree of acetyl group is X and the substitution degree of propionyl group or butyryl group is Y, X and Y are active ray curable resin layers on a transparent support having a mixed fatty acid ester of cellulose in the following range And a low reflection laminate provided with an antireflection layer is preferably used.

2.3 ≦ X + Y ≦ 3.0
0.1 ≦ Y ≦ 1.2
In particular, 2.5 ≦ X + Y ≦ 2.9
It is preferable that 0.3 ≦ Y ≦ 1.2.

  When cellulose ester is used as the transparent support used in the present invention, the cellulose used as the raw material for the cellulose ester is not particularly limited, but examples include cotton linters, wood pulp (derived from coniferous trees, derived from hardwoods), kenaf and the like. it can. Moreover, the cellulose ester obtained from them can be mixed and used in arbitrary ratios, respectively. When the acylating agent is an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride), these cellulose esters use an organic solvent such as acetic acid or an organic solvent such as methylene chloride, and It can be obtained by reacting with a cellulose raw material using a protic catalyst.

When the acylating agent is acid chloride (CH ₃ COCl, C ₂ H ₅ COCl, C ₃ H ₇ COCl), the reaction is carried out using a basic compound such as an amine as a catalyst. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804. In addition, the cellulose ester used in the present invention is obtained by mixing and reacting the amount of the acylating agent in accordance with the degree of substitution. In the cellulose ester, these acylating agents react with hydroxyl groups of cellulose molecules. Cellulose molecules are composed of many glucose units linked together, and the glucose unit has three hydroxyl groups. The number of acyl groups derived from these three hydroxyl groups is called the degree of substitution (mol%). For example, cellulose triacetate has acetyl groups bonded to all three hydroxyl groups of the glucose unit (actually 2.6 to 3.0).

  As the cellulose ester used in the present invention, a mixed fatty acid ester of cellulose in which a propionate group or a butyrate group is bonded in addition to an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, or cellulose acetate propionate butyrate Is particularly preferably used. The butyryl group that forms butyrate may be linear or branched.

  Cellulose acetate propionate containing a propionate group as a substituent has excellent water resistance and is useful as a film for liquid crystal image display devices.

  The measuring method of the substitution degree of an acyl group can be measured according to the rule of ASTM-D817-96.

  The number average molecular weight of the cellulose ester is preferably 70000 to 250,000, since it has high mechanical strength when molded and an appropriate dope viscosity, and more preferably 80000 to 150,000.

  These cellulose ester films are prepared by applying a cellulose ester solution (dope) generally called a solution casting film forming method onto, for example, an endless metal belt for infinite transfer or a support for casting of a rotating metal drum. It is preferable to manufacture the dope from a pressure die by casting (casting).

(Organic solvent)
The organic solvent used for preparing these dopes is preferably capable of dissolving cellulose ester and having an appropriate boiling point, for example, methylene chloride, methyl acetate, ethyl acetate, amyl acetate, methyl acetoacetate, acetone, tetrahydrofuran 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol, 1,3-difluoro-2 -Propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3 , 3,3-pentafluoro-1-propanol, nitroethane, 1,3-dimethyl-2-imidazolidinone, etc. Can, organic halogen compounds such as methylene chloride, dioxolane derivatives, methyl acetate, ethyl acetate, acetone, methyl acetoacetate, and the like are preferable organic solvents (i.e., good solvent), and as.

  Moreover, as shown in the following film forming process, it is used from the viewpoint of preventing foaming in the web when the solvent is dried from the web (dope film) formed on the casting support in the solvent evaporation process. The boiling point of the organic solvent is preferably 30 to 80 ° C. For example, the good solvent described above has a boiling point of methylene chloride (boiling point 40.4 ° C), methyl acetate (boiling point 56.32 ° C), acetone (boiling point 56.56 ° C). 3 ° C.), ethyl acetate (boiling point 76.82 ° C.) and the like.

  Among the good solvents described above, methylene chloride or methyl acetate, which is excellent in solubility, is preferably used.

  In addition to the organic solvent, it is preferable to contain 0.1 to 40% by mass of an alcohol having 1 to 4 carbon atoms. It is particularly preferable that the alcohol is contained at 5 to 30% by mass. After casting the dope described above onto a casting support, the solvent starts to evaporate and the alcohol ratio increases and the web (dope film) gels, making the web strong and peeling from the casting support. It is also used as a gelling solvent for facilitating the dissolution, and when these ratios are small, it also has a role of promoting dissolution of the cellulose ester of the non-chlorine organic solvent.

  Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol and the like.

  Of these solvents, ethanol is preferred because it has good dope stability, relatively low boiling point, good drying properties, and no toxicity. It is preferable to use a solvent containing 5 to 30% by mass of ethanol with respect to 70 to 95% by mass of methylene chloride. Methyl acetate can be used in place of methylene chloride. At this time, the dope may be prepared by a cooling dissolution method.

(Plasticizer)
When a cellulose ester film is used for the antireflection film of the present invention, it is preferable to contain the following plasticizer. Examples of plasticizers include phosphate ester plasticizers, phthalate ester plasticizers, trimellitic acid ester plasticizers, pyromellitic acid plasticizers, glycolate plasticizers, citrate ester plasticizers, and polyesters. A plasticizer or the like can be preferably used.

  For phosphate plasticizers, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenylbiphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. For phthalate ester plasticizers, diethyl phthalate, dimethoxy For trimellitic acid plasticizers such as ethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, diphenyl phthalate, dicyclohexyl phthalate, tributyl trimellitate, triphenyl trimellitate, triethyl For pyromellitic acid ester plasticizers such as trimellitate, tetrabutylpyromellitate, In the case of glycolate plasticizers such as lupyromelitate and tetraethylpyromellitate, triacetin, tributyrin, ethylphthalylethyl glycolate, methylphthalylethyl glycolate, butylphthalylbutyl glycolate, etc. Citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2-ethylhexyl) citrate and the like can be preferably used. Examples of other carboxylic acid esters include trimethylolpropane tribenzoate, butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters.

  As the polyester plasticizer, a copolymer of a dibasic acid and a glycol such as an aliphatic dibasic acid, an alicyclic dibasic acid, or an aromatic dibasic acid can be used. The aliphatic dibasic acid is not particularly limited, and adipic acid, sebacic acid, phthalic acid, terephthalic acid, 1,4-cyclohexyl dicarboxylic acid, and the like can be used. As glycol, ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol and the like can be used. These dibasic acids and glycols may be used alone or in combination of two or more.

  The amount of these plasticizers used is preferably from 1 to 20% by mass, particularly preferably from 3 to 13% by mass, based on the cellulose ester, in terms of film performance, processability and the like.

(UV absorber)
For the long film for the low reflection laminate of the present invention, an ultraviolet absorber is preferably used.

  As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having a small absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties.

  Specific examples of the ultraviolet absorber preferably used in the present invention include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. However, it is not limited to these.

  Specific examples of the benzotriazole-based ultraviolet absorbers include the following ultraviolet absorbers, but the present invention is not limited thereto.

UV-1: 2- (2'-hydroxy-5'-methylphenyl) benzotriazole UV-2: 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole UV-3 : 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole UV-4: 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl)- 5-Chlorobenzotriazole UV-5: 2- (2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl) benzotriazole UV-6: 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol)
UV-7: 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole UV-8: 2- (2H-benzotriazol-2-yl) -6 (Linear and side chain dodecyl) -4-methylphenol (TINUVIN171, manufactured by Ciba)
UV-9: Octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl- Mixture of 4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate (TINUVIN 109, manufactured by Ciba)
Moreover, although the following specific example is shown as a benzophenone series ultraviolet absorber, this invention is not limited to these.

UV-10: 2,4-dihydroxybenzophenone UV-11: 2,2'-dihydroxy-4-methoxybenzophenone UV-12: 2-hydroxy-4-methoxy-5-sulfobenzophenone UV-13: Bis (2-methoxy -4-hydroxy-5-benzoylphenylmethane)
As the ultraviolet absorber preferably used in the present invention, a benzotriazole-based ultraviolet absorber and a benzophenone-based ultraviolet absorber that are highly transparent and excellent in preventing the deterioration of the polarizing plate and the liquid crystal are preferable, and unnecessary coloring is less. A benzotriazole-based ultraviolet absorber is particularly preferably used.

  Moreover, the ultraviolet absorber whose distribution coefficient described in Unexamined-Japanese-Patent No. 2001-187825 is 9.2 or more improves the surface quality of a long film, and is excellent also in applicability | paintability. In particular, it is preferable to use an ultraviolet absorber having a distribution coefficient of 10.1 or more.

  Further, the polymer ultraviolet absorber described in the general formula (1) or general formula (2) described in JP-A-6-148430 and the general formulas (2), (6), and (7) described in Japanese Patent Application No. 2000-156039 (Or UV-absorbing polymer) is also preferably used. As a polymer ultraviolet absorber, PUVA-30M (manufactured by Otsuka Chemical Co., Ltd.) and the like are commercially available.

(Fine particles)
Moreover, in order to provide slipperiness to the cellulose-ester film used for this invention, the microparticles | fine-particles similar to what is described with the coating layer containing the below-mentioned actinic radiation curable resin can be used.

  As fine particles, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, Mention may be made of magnesium silicate and calcium phosphate. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable.

  The average primary particle size of the fine particles is preferably 5 to 50 nm, and more preferably 7 to 20 nm. These are preferably contained mainly as secondary aggregates having a particle size of 0.05 to 0.3 μm. The content of these fine particles in the cellulose ester film is preferably 0.05 to 1% by mass, particularly preferably 0.1 to 0.5% by mass. In the case of a cellulose ester film having a multilayer structure by the co-casting method, it is preferable to contain fine particles of this addition amount on the surface.

  Silicon dioxide fine particles are commercially available, for example, under the trade names Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.). it can.

  Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used.

  Examples of the polymer include silicone resin, fluororesin, and acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large effect of reducing the friction coefficient while keeping the turbidity of the cellulose ester film low. In the cellulose ester film used in the present invention, the dynamic friction coefficient on the back side of the active energy ray-curable resin layer is preferably 1.0 or less.

(Method for producing cellulose ester film)
Next, the manufacturing method of a cellulose-ester film is demonstrated.

  The cellulose ester film is produced by dissolving the cellulose ester and additives in a solvent to prepare a dope, casting the dope on a belt-like or drum-like metal support, and drying the cast dope as a web. It is performed by the process of carrying out, the process of peeling from a metal support body, the process of extending | stretching or maintaining width, the process of drying further, and the process of winding up the finished film.

  The process for preparing the dope will be described. The concentration of cellulose ester in the dope is preferably higher because the drying load after casting on the metal support can be reduced. However, if the concentration of cellulose ester is too high, the load during filtration increases and the filtration accuracy increases. Becomes worse. The concentration for achieving both of these is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass.

  The solvent used in the dope may be used alone or in combination of two or more, but it is preferable to use a mixture of a good solvent and a poor solvent of cellulose ester in terms of production efficiency, and there are many good solvents. This is preferable from the viewpoint of the solubility of the cellulose ester. The preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass for the good solvent and 2 to 30% by mass for the poor solvent. With a good solvent and a poor solvent, what dissolve | melts the cellulose ester to be used independently is defined as a good solvent, and what poorly swells or does not melt | dissolve is defined as a poor solvent. Therefore, depending on the acyl group substitution degree of the cellulose ester, the good solvent and the poor solvent change. For example, when acetone is used as the solvent, the cellulose ester acetate ester (acetyl group substitution degree 2.4) and cellulose acetate propionate are good. As a solvent, cellulose acetate (acetyl group substitution degree 2.8) is a poor solvent.

  Although the good solvent used for this invention is not specifically limited, Organic halogen compounds, such as a methylene chloride, dioxolanes, acetone, methyl acetate, methyl acetoacetate, etc. are mentioned. Particularly preferred is methylene chloride or methyl acetate.

  Moreover, although the poor solvent used for this invention is not specifically limited, For example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone, etc. are used preferably. Moreover, it is preferable that 0.01-2 mass% of water contains in dope.

  A general method can be used as a dissolution method of the cellulose ester when preparing the dope described above. When heating and pressurization are combined, it is possible to heat above the boiling point at normal pressure. It is preferable to stir and dissolve while heating at a temperature that is equal to or higher than the boiling point of the solvent at normal pressure and that the solvent does not boil under pressure, in order to prevent the generation of massive undissolved materials called gels and mamacos. Moreover, after mixing a cellulose ester with a poor solvent and making it wet or swell, the method of adding a good solvent and melt | dissolving is also used preferably.

  The pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside. For example, a jacket type is preferable because temperature control is easy.

  The heating temperature with the addition of the solvent is preferably higher from the viewpoint of the solubility of the cellulose ester, but if the heating temperature is too high, the required pressure increases and the productivity deteriorates. A preferable heating temperature is 45 to 120 ° C, more preferably 60 to 110 ° C, and still more preferably 70 ° C to 105 ° C. The pressure is adjusted so that the solvent does not boil at the set temperature.

  Alternatively, a cooling dissolution method is also preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.

  Next, this cellulose ester solution is filtered using a suitable filter medium such as filter paper. As the filter medium, it is preferable that the absolute filtration accuracy is small in order to remove insoluble matters and the like. However, if the absolute filtration accuracy is too small, there is a problem that the filter medium is likely to be clogged. For this reason, a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium with 0.001 to 0.008 mm is more preferable, and a filter medium with 0.003 to 0.006 mm is more preferable.

  There are no particular restrictions on the material of the filter medium, and ordinary filter media can be used. However, plastic filter media such as polypropylene and Teflon (registered trademark), and metal filter media such as stainless steel do not drop off fibers. preferable. It is preferable to remove and reduce impurities, particularly bright spot foreign matter, contained in the raw material cellulose ester by filtration.

A bright spot foreign substance is when two polarizing plates are placed in a crossed Nicol state, a cellulose ester film is placed between them, light is applied from the side of one polarizing plate, and observed from the side of the other polarizing plate. It is a point (foreign matter) where light from the opposite side appears to leak, and the number of bright spots having a diameter of 0.01 mm or more is preferably 200 / cm ² or less. More preferably, it is 100 pieces / cm < ² > or less, More preferably, it is 50 pieces / m < ² > or less, More preferably, it is 0-10 pieces / cm < ² > or less. Further, it is preferable that the number of bright spots of 0.01 mm or less is small.

  The dope can be filtered by a normal method, but the method of filtering while heating at a temperature not lower than the boiling point of the solvent at normal pressure and in a range where the solvent does not boil under pressure is the filtration pressure before and after filtration. The increase in the difference (referred to as differential pressure) is small and preferable. A preferred temperature is 45 to 120 ° C, more preferably 45 to 70 ° C, and even more preferably 45 to 55 ° C.

  A smaller filtration pressure is preferred. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.

  Here, the dope casting will be described.

  The metal support in the casting (casting) step preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support. The cast width can be 1 to 4 m. The surface temperature of the metal support in the casting step is set to −50 ° C. to a temperature at which the solvent boils and does not foam. A higher temperature is preferred because the web can be dried faster, but if it is too high, the web may foam or the flatness may deteriorate. A preferable metal support temperature is appropriately determined at 0 to 100 ° C, and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short. When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming. . In particular, it is preferable to efficiently dry by changing the temperature of the metal support and the temperature of the drying air during the period from casting to peeling.

  In order for the cellulose ester film to exhibit good flatness, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. Especially preferably, it is 20-30 mass% or 70-120 mass%.

  In the present invention, the amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Note that M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  Further, in the drying step of the cellulose ester film, the web is peeled off from the metal support, and further dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, Especially preferably, it is 0-0.01 mass% or less.

  In the film drying process, generally, a roll drying method (a method in which a plurality of rolls arranged on the upper and lower sides are alternately passed through and dried) or a tenter method is used while drying the web.

  In order to produce the cellulose ester film for the antireflection film of the present invention, the web is stretched in the conveying direction where the residual solvent amount of the web immediately after peeling from the metal support is large, and both ends of the web are gripped with clips or the like. It is particularly preferable to perform stretching in the width direction by a tenter method. A preferable draw ratio in both the machine direction and the transverse direction is 1.05 to 1.3 times, and more preferably 1.05 to 1.15 times. It is preferable that the area is 1.12 to 1.44 times, and preferably 1.15 to 1.32 times due to longitudinal and lateral stretching. This can be determined by the draw ratio in the longitudinal direction × the draw ratio in the transverse direction. If one of the draw ratios in the machine direction and the transverse direction is less than 1.05 times, the deterioration of flatness due to ultraviolet irradiation when forming the active energy ray-curable resin layer is unfavorable. Moreover, even if a draw ratio exceeds 1.3 times, since planarity deteriorates and haze also increases, it is not preferable.

  In order to stretch in the machine direction immediately after peeling, it is preferable to stretch by peeling tension and subsequent transport tension. For example, it is preferable to peel at a peeling tension of 210 N / m or more, and particularly preferably 220 to 300 N / m.

  The means for drying the web is not particularly limited, and can be generally performed with hot air, infrared rays, a heating roll, microwave, or the like, but is preferably performed with hot air in terms of simplicity.

  The drying temperature in the web drying step is preferably increased stepwise from 30 to 150 ° C, and more preferably from 50 to 140 ° C in order to improve dimensional stability.

  Although the film thickness of a cellulose-ester film is not specifically limited, 10-200 micrometers is used preferably. In particular, it was difficult to obtain an antireflection film excellent in flatness and hardness with a thin film of 10 to 70 μm, but according to the present invention, a thin antireflection film excellent in flatness and hardness was obtained, Moreover, since it is excellent also in productivity, it is especially preferable that the film thickness of a cellulose-ester film is 10-70 micrometers. More preferably, it is 20-60 micrometers. Most preferably, it is 35-60 micrometers. Moreover, the cellulose ester film made into the multilayer structure by the co-casting method can also be used preferably. Even when the cellulose ester has a multilayer structure, it has a layer containing an ultraviolet absorber and a plasticizer, and it may be a core layer, a skin layer, or both.

  The antireflection film of the present invention preferably has a width of 1.4 to 5 m. The surface of the cellulose ester film (transparent support), particularly the surface on which the low refractive index layer is provided, has an arithmetic average roughness (Ra) of 50 to less than 1000 nm, preferably 80 to 600 nm. When Ra is less than 50 nm, the antiglare effect is weak, and when it exceeds 1000 nm, an impression that is too coarse is visually observed. Arithmetic average roughness (Ra) is preferably measured with an optical interference type surface roughness measuring device in the same manner as the hard coat layer. For example, an optical interference type surface roughness meter RST / PLUS (manufactured by WYKO) is used. Can be measured.

  The method for forming an uneven shape having an arithmetic average roughness (Ra) of less than 50 to 1000 nm on the surface of the transparent support has been described in the section of antiglare property. An embossing method that is preferably used as a method for forming an uneven shape on the surface of the transparent support will be described below.

  First, in the film forming process of the transparent support, a method of pressing the concavo-convex roller as a mold on the film surface to form the concavo-convex on the front or back surface will be described with reference to the drawings. The figure shows an example, and the present invention is not limited to these.

  Examples of the mold include a concavo-convex roller having a concavo-convex surface, but a plate-shaped, film-shaped, or belt-shaped mold may also be used.

  FIG. 1 is a schematic view of an uneven surface forming apparatus using an uneven roller. A preliminarily prepared resin solution is cast from a die 1 onto a casting belt 2 to form a web (a film containing a residual solvent after casting a dope on a metal support is referred to as a web), After peeling, a concavo-convex surface is formed on the web by the concavo-convex roller 3 for forming the concavo-convex surface and the back roll 4 facing it. Next, in the same manner, an uneven surface is formed on the back surface of the web by the uneven surface forming uneven roller 3 ′ having an uneven shape on the opposite surface of the web and the back roll 4, and then the web is stretched by the tenter 5. The film is dried by a film drying device 6 and wound by a winding roll 7.

  Further, the uneven surface may be formed after the tenter 5 in FIG. 1, in the drying device 6 in FIG. 1, or after the drying is completed. Although unevenness formation is performed by arranging a roller and a back roll, a plurality of uneven rollers and a back roll may be used.

  FIG. 2 shows a schematic view of an uneven surface forming apparatus in the drying apparatus. In this case, the amount of residual solvent is significantly lower than in the case of FIG. 1, but the temperature of the transparent support surface can be set to a desired temperature by controlling the heating conditions with the drying device, so that the unevenness can be formed with high accuracy. There are advantages you can do.

  After returning the film to room temperature, a concavo-convex surface forming apparatus using a concavo-convex roller can be used in another line. However, in this case, if the residual solvent or temperature is low, the concavo-convex surface formation is not stable. In addition, there is a risk of dust and foreign matter adhering to the uneven roller by the uneven roller, and as shown in FIGS. Is also easy to form.

  As the concavo-convex type roller used for the formation of the concavo-convex surface, it is possible to select and apply as appropriate to fine rugged and rough rugged, pattern, mat shape, lenticular lens shape, concave or convex portion consisting of part of a spherical surface, prism shape Can be used in which the embosses for forming the irregularities are regularly or randomly arranged. For example, a concave portion or a convex portion made of a part of a sphere having a diameter of the convex portion or the concave portion of 5 to 100 μm and a height of 0.1 to 2 μm can be mentioned, and these may combine large unevenness and small unevenness. .

  The material of the concavo-convex roller and the back roll can be metal, stainless steel, carbon steel, aluminum alloy, titanium alloy, ceramic, hard rubber, reinforced plastic, or a combination of these materials. From this point, the concavo-convex roller is preferably a metal. In particular, the ease of cleaning and durability are also important, and it is preferable to use a stainless uneven roller. Particularly preferably, the surface-side uneven shape is formed of a metal material and a ceramic material for the viewing side, and the surface uneven shape is formed of a rubber material for the back side. By using concavo-convex rollers made of different materials, concavo-convex shapes having slightly different concavo-convex shapes (shapes such as peaks, valleys, and ridge lines) can be formed, and glare can be effectively prevented.

  Further, the surface may be subjected to water repellency or water repellency treatment. As a method of forming a desired concavo-convex surface on the concavo-convex roller, it can be formed by using an etching method, a sand blasting method, a mechanical processing method, a mold, or the like. As the back roll, hard rubber or metal is preferably used.

  The surface temperature T1 of the concavo-convex roller is preferably T2 + 10 ° C. to T2 + 55 ° C., preferably T2 + 30 ° C. to T2 + 50 ° C., with respect to the thermal deformation temperature T2 of the resin used. The heat distortion temperature T2 is a value measured according to ASTM D-648.

  If the surface temperature T1 of the concavo-convex roller is lower than the thermal deformation temperature T2, it becomes difficult to form a fine concavo-convex shape. When the surface temperature T1 exceeds 55 ° C. than the thermal deformation temperature T2, the flatness of the obtained film tends to deteriorate. The surface temperature T1 of the concavo-convex roller can be controlled by setting the temperature of the concavo-convex roller itself, the ambient temperature, the film temperature for forming the concavo-convex, the residual solvent amount of the film, and the concavo-convex forming speed. The temperature of the concavo-convex roller itself can be controlled by circulating a temperature-controlled gas or liquid medium in the concavo-convex roller. For example, it is selected according to the type of resin and the uneven shape to be formed in the range of 40 to 300 ° C., preferably 50 to 250 ° C. At that time, it is preferable to prevent the residual solvent in the film from foaming, and even if the surface of the concavo-convex roller is at a temperature equal to or higher than the boiling point of the residual solvent, foaming can be prevented if the concavo-convex formation speed is high. . For example, the unevenness can be formed at a speed of 10 m / min or more.

  It is preferable to control the temperature of the back roll in the same manner, and it is preferable to set the temperature to be equal to or lower than that of the uneven roller.

  The roll pressure at the time of forming the unevenness is appropriately determined from a linear pressure of 5 to 500 N / cm, more preferably from 30 to 500 N / cm in consideration of the type of the thermoplastic resin, the shape of the unevenness to be formed, the temperature, and the like. .

  When the width of the cellulose ester film becomes wider, the illuminance unevenness of the irradiated light during UV curing cannot be ignored, not only the flatness deteriorates but also the hardness unevenness. When the antireflection layer is formed on this, the reflection unevenness There was a problem that became prominent. Since the antireflection film of the present invention can provide sufficient hardness with a small amount of irradiation, even if there is unevenness of the irradiation amount in the width direction of the irradiation light, unevenness of the hardness in the width direction is unlikely to occur, and the flatness is excellent. Since an antireflection film is obtained, a remarkable effect is recognized with a wide cellulose ester film. In particular, those having a width of 1.4 to 4 m are preferably used, and particularly preferably 1.4 to 3 m. If it exceeds 4 m, conveyance becomes difficult.

(Antireflection layer)
In the present invention, a method for providing an antireflection layer such as a low refractive index layer is not particularly limited, but it is preferably formed by coating.

  In the present invention, it is preferable to produce an antireflection layer by sequentially coating other functional layers on the cellulose ester film provided with a hard coat layer, using the above-described low refractive index layer composition.

  Although the structure of a preferable antireflection film is shown below, it is not limited to these.

  Here, the hard coat layer means the aforementioned active energy ray-curable resin layer.

Transparent support / hard coat layer / low refractive index layer Transparent support / hard coat layer / high refractive index layer / low refractive index layer Transparent support / antistatic layer / hard coat layer / high refractive index layer / low refractive index layer Transparent support / antiglare hard coat layer / high refractive index layer / low refractive index layer Transparent support / antistatic layer / antiglare hard coat layer / high refractive index layer / low refractive index layer Outer surface of antireflection film The arithmetic average roughness (Ra) is preferably 40 to less than 500 nm, preferably 60 to 300 nm.

  As a method of forming such unevenness on the outermost surface of the antireflection film, there is a method of processing the unevenness to the antireflection film after applying the antireflection layer as described above. In the present invention, processing to a transparent support and processing to a hard coat layer are preferred because the antireflection layer may be broken or the antireflection layer may be deformed to impair the antireflection effect. Unevenness is also formed on the outermost surface of the antireflection film by processing to the transparent support and processing to the hard coat layer.

  The arithmetic average roughness (Ra) of the outermost surface of the antireflection film can be measured using, for example, an optical interference type surface roughness meter RST / PLUS (manufactured by WYKO) in the same manner as the hard coat layer.

  In any case, the back coat layer described above is preferably provided on the surface of the transparent support opposite to the side on which the low refractive index layer is applied.

  In the present invention, after the hard coat layer is formed, the surface of the hard coat layer is preferably subjected to surface treatment, and the low refractive index layer according to the present invention is formed on the surface of the hard coat layer subjected to the surface treatment.

  The reflectance of the antireflection film according to the present invention can be measured with a spectrophotometer. At that time, after the surface on the measurement side of the sample is roughened, the light absorption treatment is performed using a black spray, and then the reflected light in the visible light region (400 to 700 nm) is measured. The reflectance is preferably as low as possible, but the average value in the visible light wavelength is preferably 1.5% or less, and the minimum reflectance is preferably 0.8% or less. Moreover, it is preferable to have a flat reflection spectrum in the visible light wavelength region.

  In addition, the reflection hue on the surface of the polarizing plate that has undergone antireflection treatment is often colored red or blue due to the high reflectance in the short wavelength region and long wavelength region in the visible light region due to the design of the antireflection film. The color tone of the reflected light varies depending on the application, and when used on the outermost surface of an FPD television or the like, a neutral color tone is desired. In this case, generally preferred reflection hue ranges are 0.17 ≦ x ≦ 0.27 and 0.07 ≦ y ≦ 0.17 on the XYZ color system (CIE1931 color system).

  The film thickness of the low refractive index layer can be obtained by calculation according to a conventional method in consideration of the reflectance and the color of reflected light rather than the refractive index of the layer.

  Examples of the surface treatment of the hard coat layer include a cleaning method, an alkali treatment method, a flame plasma treatment method, a high frequency discharge plasma method, an electron beam method, an ion beam method, a sputtering method, an acid treatment, a corona treatment method, and an atmospheric pressure plasma method. The alkali treatment method, the corona treatment method, and the atmospheric pressure plasma method are preferable, and the atmospheric pressure plasma method is particularly preferable.

(Corona treatment method)
The corona treatment is a treatment performed by applying a high voltage of 1 kV or higher between the electrodes under atmospheric pressure and discharging it. An apparatus commercially available from Kasuga Electric Co., Ltd. or Toyo Electric Co., Ltd. Can be used. The intensity of the corona discharge treatment depends on the distance between the electrodes, the output per unit area, and the generator frequency. As one electrode (A electrode) of the corona treatment apparatus, a commercially available one can be used, but the material can be selected from aluminum, stainless steel and the like. The other is an electrode (B electrode) for holding a plastic film, and is a roll electrode installed at a certain distance from the A electrode so that the corona treatment is carried out stably and uniformly. A commercially available one can also be used, and the material is preferably a roll made of aluminum, stainless steel, or a metal thereof and lined with ceramic, silicone, EPT rubber, hyperon rubber, or the like. It is done. The frequency used for the corona treatment used in the present invention is a frequency of 20 to 100 kHz, and a frequency of 30 to 60 kHz is preferable. When the frequency is lowered, the uniformity of the corona treatment is deteriorated and unevenness of the corona treatment occurs. In addition, when the frequency is increased, there is no particular problem when performing high-output corona treatment, but when performing low-output corona treatment, it is difficult to perform stable processing, resulting in uneven processing. Occurs. The output of the corona treatment is 1 to 5 w · min. / M ² but ² to 4 w · min. An output of / m ² is preferred. The distance between the electrode and the film is 5 to 50 mm, preferably 10 to 35 mm. When the gap is opened, a higher voltage is required to maintain a constant output, and unevenness is likely to occur. On the other hand, if the gap is too narrow, the applied voltage becomes too low and unevenness is likely to occur. Furthermore, when the film is transported and continuously processed, the film comes into contact with the electrodes and scratches are generated.

(Alkaline treatment method)
The alkali treatment method is not particularly limited as long as it is a method in which a film coated with a hard coat layer is immersed in an alkaline aqueous solution.

  As the aqueous alkali solution, an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, an aqueous ammonia solution or the like can be used, and an aqueous sodium hydroxide solution is particularly preferable.

  The alkali concentration of the aqueous alkali solution, for example, sodium hydroxide concentration is preferably 0.1 to 25% by mass, and more preferably 0.5 to 15% by mass.

  The alkali treatment temperature is usually 10 to 80 ° C, preferably 20 to 60 ° C.

  The alkali treatment time is 5 seconds to 5 minutes, preferably 30 seconds to 3 minutes. The film after the alkali treatment is preferably neutralized with acidic water and then thoroughly washed with water.

(Atmospheric pressure plasma method)
In the present invention, a discharge is formed by applying a high-frequency voltage having a frequency of 50 kHz to 150 MHz between opposing electrodes under atmospheric pressure or a pressure in the vicinity thereof, and the excitation gas formed by the discharge is transferred to a transparent support. Or after making it contact the surface of the film which has a hard-coat layer on a transparent support body, it is preferable to form an antireflection layer by application | coating.

  The frequency is preferably 50 kHz to 27 MHz.

  The opposed electrodes are composed of a first electrode and a second electrode, and the frequency of the high-frequency voltage applied to either one of the electrodes is preferably 50 kHz to 150 MHz. Moreover, it is preferable that the frequency of the high frequency voltage applied to the first electrode is 1 to 200 kHz, and the frequency of the high frequency voltage applied to the second electrode is 800 kHz to 150 MHz.

  Hereinafter, the plasma discharge treatment performed under atmospheric pressure or a pressure in the vicinity thereof is also simply referred to as an atmospheric pressure plasma method.

That is, the present invention provides a transparent electrode or a film having a hard coat layer on the transparent substrate between a counter electrode composed of a first electrode and a second electrode under atmospheric pressure or a pressure near the first electrode. A high frequency voltage having a voltage component of the first frequency ω ₁ is applied to the second electrode, and a high frequency voltage having a voltage component of the second frequency ω ₂ is applied to the second electrode to form a discharge. After bringing the surface of the transparent support into contact with the excitation gas, an antireflection layer is formed thereon.

  As the atmospheric pressure plasma method applicable to the present invention, JP-A-11-133205, JP-A-2000-185362, JP-A-11-61406, JP-A-2000-147209, 2000-121804 are disclosed. The technology disclosed in the above can be referred to.

  The atmospheric pressure plasma method used in the present invention will be described.

  First, an atmospheric pressure plasma method and apparatus useful for the present invention will be described.

  In the present invention, a gas is supplied to the discharge space (between the counter electrodes) at atmospheric pressure or in the vicinity thereof, a high-frequency voltage is applied to the discharge space, and the gas is excited into a plasma state. A transparent support or the surface of a film having a hard coat layer on the transparent support is exposed to a state gas. The high frequency voltage applied to the discharge space formed between the counter electrodes may be a high frequency of one frequency, or may be a high frequency of two or more frequencies.

  In the present invention, the atmospheric pressure plasma treatment is performed under atmospheric pressure or a pressure in the vicinity thereof, and the atmospheric pressure or the pressure in the vicinity thereof is about 20 to 110 kPa, so that the good effects described in the present invention can be obtained. Is preferably 93 to 104 kPa.

  In the present invention, the gas supplied between the counter electrodes (discharge space) is at least an excitation gas excited by a high-frequency voltage, or a gas that receives an excitation gas excited by a high-frequency voltage and its energy and enters a plasma state or an excited state. Including. The high frequency as used in this invention means what has a frequency of at least 0.5 kHz.

  When plasma discharge treatment is performed with a high-frequency voltage of one frequency (sometimes referred to as a one-frequency high-frequency voltage application method), or plasma discharge treatment is performed with a high-frequency voltage of two frequencies (sometimes referred to as a two-frequency high-frequency voltage application method). The same electrodes can be used, and the apparatus itself is not significantly different. The difference is that there are two high-frequency power supplies and a filter associated therewith, and furthermore, a high-frequency voltage is applied from both electrodes of the counter electrode.

  In the case of the one-frequency high-frequency voltage application method useful in the present invention, one of the counter electrodes is a ground electrode, and the other is an application electrode. A high-frequency power source is connected to the application electrode, and the ground is grounded to the ground electrode. Has been.

  The thin film forming apparatus (atmospheric pressure plasma processing apparatus) of each of the 1-frequency high-frequency voltage application method and the 2-frequency high-frequency voltage application method will be described using the drawings.

  FIG. 3 is a schematic view showing an example of a 1-frequency high-frequency voltage application type thin film forming apparatus useful for the present invention.

  A counter electrode is formed by an application electrode (square tube electrode) 136 for applying a high-frequency voltage inside the plasma discharge vessel 130 and a roll-type ground electrode 135 around which the base film F is wound. Any number of application electrodes 136 may be arranged. The gas G is supplied from the gas supply port 152 of the plasma discharge vessel 10, passes through a mesh for uniformizing the gas G, passes between the application electrodes 136 and along the inner wall of the application electrode and the plasma discharge vessel 131, and The discharge space 13 is filled with the gas G. A high frequency voltage is applied to the application electrode 136 by the high frequency power source 21, and the base film F is exposed to the gas G excited in the discharge space 132. The frequency of the high frequency voltage to be applied is preferably 50 kHz or more. More preferably, it is in the range of 50 kHz to 150 MHz.

  If it is less than 50 kHz, the effect of the present invention cannot be obtained. Further, a frequency exceeding 150 MHz is not suitable for the present invention because it is difficult to form a discharge and complicated equipment is required, and because nonuniform processing occurs due to potential distribution generation, making it unsuitable for large area processing. Conceivable.

  While the base film F is exposed to the excited gas G, the electrode is heated or cooled via the pipe from the electrode temperature adjusting means 160. As the temperature control medium, an insulating material such as distilled water or oil is preferably used. During the plasma discharge treatment, it is desirable to uniformly adjust the temperature inside the electrode so that the temperature unevenness of the substrate in the width direction or the longitudinal direction does not occur as much as possible.

  In the present invention, the base film F is the transparent support film, that is, the base film, a film in which a hard coat layer is coated on the base film, or a high refractive index layer and / or a medium thereon. It may be a film coated with a refractive index layer.

  FIG. 4 is a schematic view showing another example of a thin film forming apparatus of a two-frequency high-frequency voltage application system useful for the present invention. In the same manner as in FIG. 3, the base film F is subjected to plasma discharge treatment between the opposed electrodes (discharge space) 132 between the roll electrode (first electrode) 135 and the square tube electrode group (second electrode) 136. is there.

In the discharge space (between the counter electrodes) 132 between the roll electrode (first electrode) 135 and the rectangular tube electrode group (second electrode) 136, the roll electrode (first electrode) 135 has a frequency from the first electrode 141. A high frequency voltage V ₁ is applied to ω ₁ , and a high frequency voltage V ₂ having a frequency ω ₂ from the second power source 142 is applied to the rectangular tube electrode group (second electrode) 136.

  A first filter 143 is installed between the roll electrode (first electrode) 135 and the first power supply 141 so that the current from the first power supply 141 flows toward the roll electrode (first electrode) 135. The first filter is designed to make it difficult for the current from the first power source 141 to pass through and to easily pass the current from the second power source 142. Also, a second filter 144 is installed between the square tube electrode group (second electrode) 136 and the second power source 142 so that the current from the second power source flows toward the second electrode, The second filter 144 is designed to make it difficult for the current from the second power supply 142 to pass through and to easily pass the current from the first power supply 141. Here, being difficult to pass means that it preferably passes only 20% or less of the current, more preferably 10% or less. On the contrary, being easy to pass means preferably passing 80% or more of the current, more preferably 90% or more.

  In the present invention, any filter having the above properties can be used without limitation. For example, as the first filter, a capacitor of several tens to several tens of thousands pF or a coil of about several μH can be used according to the frequency of the second power source. As the second filter, a coil of 10 μH or more is used according to the frequency of the first power supply, and it can be used as a filter by grounding through these coils or capacitors.

In the present invention, the roll electrode 135 may be the second electrode, and the rectangular tube electrode group 136 may be the first electrode. In any case, the first power source is connected to the first electrode, and the second power source is connected to the second electrode. Furthermore, the first power source only needs to have the ability to apply a higher frequency voltage (V ₁ > V ₂ ) than the second power source. Moreover, the frequency should just have the capability to become (omega) ₁ <(omega) ₂ .

  The gas G generated by the gas supply device 151 of the gas supply means 150 is introduced into the plasma discharge processing vessel 131 through the air supply port 152 while controlling the flow rate. The discharge space 132 and the plasma discharge treatment container 131 are filled with the gas G.

  The base film F is unwound from the original winding which is unwound and is transported, or is transported from the previous step, and is accompanied by the base film by the nip roll 165 via the guide roll 164, etc. , And while being in contact with the roll electrode 135, it is transferred to and from the rectangular tube electrode group 136, and both the roll electrode (first electrode) 135 and the rectangular tube electrode group (second electrode) 136 are transferred. A voltage is applied from above to generate discharge plasma between the counter electrodes (discharge space) 132. The base film F is exposed to a plasma state gas while being wound while being in contact with the roll electrode 135. The base film F passes through the nip roll 166 and the guide roll 167, and is taken up by a winder (not shown) or transferred to the next step.

  Discharged treated exhaust gas G ′ is discharged from the exhaust port 153.

  During exposure to the plasma state gas, in order to heat or cool the roll electrode (first electrode) 135 and the rectangular tube electrode group (second electrode) 136, a medium whose temperature is adjusted by the electrode temperature adjusting means 160 is used. It sends to both electrodes through the piping 161 with the liquid feeding pump P, and adjusts temperature from the electrode inner side. Reference numerals 165 and 166 denote partition plates that partition the plasma discharge processing vessel 131 from the outside.

  In the present invention, the high-frequency voltage to be applied may be an intermittent pulse wave or a continuous sine wave, and is not limited to the applied voltage waveform. Sine waves are preferred for forming the thin film.

  In the present invention, the frequency of the high frequency voltage applied to the first electrode is preferably 1 to 200 kHz, and the frequency of the high frequency voltage applied to the second electrode is preferably 800 kHz or more.

The power density at that time is preferably 1 to 50 W / cm ² (where, denominator cm ² is the area where discharge occurs), more preferably 1.2 to 30 W / cm ² .

  Examples of the high-frequency power source useful in the present invention include 100 kHz * (manufactured by HEIDEN Laboratory), 200 kHz, 800 kHz, 2 MHz, 13.56 MHz, 27 MHz, and 150 MHz (all manufactured by Pearl Industry). In addition, * mark is HEIDEN Laboratory impulse high frequency power supply (100 kHz in continuous mode).

  In the present invention, it is necessary to employ an electrode capable of maintaining a uniform glow discharge state described below by applying such a voltage to the plasma discharge processing apparatus.

  FIG. 5 is a perspective view showing an example of the structure of the conductive metallic base material of the roll electrode shown in the figure and the dielectric material coated thereon.

  In FIG. 5, a roll electrode 35a is formed by covering a conductive metallic base material 35A and a dielectric 35B thereon. The inside is a hollow jacket, and the temperature is adjusted.

  FIG. 6 is a perspective view showing an example of the structure of the conductive metallic base material of the rectangular tube electrode shown in FIGS. 3 and 4 and the dielectric material coated thereon.

  In FIG. 6, a rectangular tube electrode 36a has a coating of a dielectric 36B similar to that of FIG. 5 on a conductive metallic base material 36A, and the structure of the electrode is a metallic pipe. , It becomes a jacket so that the temperature can be adjusted during discharge.

  In addition, the number of the rectangular tube-shaped electrodes is set in plural along the circumference larger than the circumference of the roll electrode, and the discharge area of the electrodes is a full-square tube electrode surface facing the roll electrode 35. It is represented by the sum of the areas.

  The rectangular tube electrode 36a shown in FIG. 6 may be a cylindrical electrode, but the rectangular tube electrode has an effect of expanding the discharge range (discharge area) as compared with the cylindrical electrode, and thus is preferably used in the present invention. .

  3 and 4, a roll electrode 35a and a rectangular tube electrode 36a are formed by spraying ceramics as dielectrics 35B and 36B on conductive metallic base materials 35A and 36A, respectively, and then sealing the inorganic compound sealing material. Used and sealed. The ceramic dielectric may be covered by about 1 mm with a single wall. As the ceramic material used for thermal spraying, alumina, silicon nitride, or the like is preferably used. Among these, alumina is particularly preferable because it is easily processed. Further, the dielectric layer may be a lining-processed dielectric provided with an inorganic material by glass lining.

  As the conductive metallic base materials 35A and 36A, a metal such as titanium or a titanium alloy, silver, platinum, stainless steel, aluminum, or iron, a composite material of iron and ceramics, or a composite material of aluminum and ceramics is used. Although it can mention, titanium or a titanium alloy is especially preferable for the reason mentioned below.

  The distance between the two electrodes (electrode gap) is determined in consideration of the thickness of the dielectric provided on the conductive metallic base material, the magnitude of the applied voltage, the purpose of using plasma, etc. The shortest distance between the dielectric surface when a dielectric is provided on one of the electrodes and the surface of the conductive metallic base material, and the distance between the dielectric surfaces when a dielectric is provided on both of the electrodes, In this case, the thickness is preferably from 0.1 to 20 mm, particularly preferably from 0.5 to 2 mm, from the viewpoint of uniform discharge.

  The plasma discharge treatment vessel 10 or 31 is preferably a treatment vessel made of Pyrex (registered trademark) glass or the like, but may be made of metal as long as it can be insulated from the electrodes. For example, polyimide resin or the like may be attached to the inner surface of an aluminum or stainless steel frame, and the metal frame may be thermally sprayed to obtain insulation. In FIG. 6, it is preferable to cover both side surfaces (up to the vicinity of the base material surface) of both parallel electrodes with an object made of the material as described above.

  Details of the conductive metallic base material and dielectric useful in the present invention will be described.

  An electrode used for such a high-power atmospheric pressure plasma method must be able to withstand severe conditions in terms of structure and performance. Such an electrode is preferably a metal base material coated with a dielectric.

In the dielectric-coated electrode used in the present invention, it is preferable that the characteristics match between various metallic base materials and dielectrics. One of the characteristics is linear thermal expansion between the metallic base material and the dielectric. The combination is such that the difference in coefficient is 10 × 10 ⁻⁶ / ° C. or less. It is preferably 8 × 10 ⁻⁶ / ° C. or less, more preferably 5 × 10 ⁻⁶ / ° C. or less, and further preferably 2 × 10 ⁻⁶ / ° C. or less. The linear thermal expansion coefficient is a well-known physical property value of a material.

As a combination of a conductive metallic base material and a dielectric whose difference in linear thermal expansion coefficient is within this range,
Metal matrix Dielectric (1) Pure titanium or titanium alloy Ceramic sprayed coating (2) Pure titanium or titanium alloy Glass lining (3) Stainless steel Ceramic sprayed coating (4) Stainless steel Glass lining (5) Composite material of ceramics and iron Ceramic sprayed coating (6) Composite material of ceramic and iron Glass lining (7) Composite material of ceramic and aluminum Ceramic sprayed coating (8) Composite material of ceramic and aluminum Glass lining and the like. From the viewpoint of the difference in linear thermal expansion coefficient, the above (1) or (2) and (5) to (8) are preferable, and (1) is particularly preferable.

  In the present invention, titanium or a titanium alloy is particularly useful as the metallic base material from the above characteristics. By using titanium or a titanium alloy as the metal base material, the dielectric is used as described above, so that there is no deterioration of the electrode in use, especially cracking, peeling, dropping off, etc., and it can be used for a long time under harsh conditions. Can withstand.

  The metallic base material of the electrode useful for the present invention is a titanium alloy or titanium containing 70% by mass or more of titanium. In the present invention, the titanium alloy or titanium in the titanium can be used without any problem as long as it is 70% by mass or more, but preferably contains 80% by mass or more of titanium. As the titanium alloy or titanium useful in the present invention, those generally used as industrial pure titanium, corrosion resistant titanium, high strength titanium and the like can be used. Examples of pure titanium for industrial use include TIA, TIB, TIC, TID, etc., all of which contain a very small amount of iron atom, carbon atom, nitrogen atom, oxygen atom, hydrogen atom, etc. As content, it has 99 mass% or more. As the corrosion-resistant titanium alloy, T15PB can be preferably used, and it contains lead in addition to the above-described atoms, and the titanium content is 98% by mass or more. Further, as the titanium alloy, T64, T325, T525, TA3, etc. containing aluminum and vanadium or tin other than the above atoms except lead can be preferably used. As a quantity, it contains 85 mass% or more. These titanium alloys or titanium have a thermal expansion coefficient about 1/2 smaller than that of stainless steel, such as AISI 316, and are well combined with a later-described dielectric applied on the titanium alloy or titanium as a metallic base material. Can withstand use at high temperature for a long time.

  On the other hand, as a required characteristic of the dielectric, specifically, an inorganic compound having a relative dielectric constant of 6 to 45 is preferable, and examples of such a dielectric include ceramics such as alumina and silicon nitride, Alternatively, there are glass lining materials such as silicate glass and borate glass. In this, what sprayed the ceramics mentioned later and the thing provided by glass lining are preferable. In particular, a dielectric provided by spraying alumina is preferable.

  Alternatively, as one of the specifications that can withstand high power as described above, the porosity of the dielectric is 10% by volume or less, preferably 8% by volume or less, preferably more than 0% by volume and 5% by volume or less. It is. The porosity of the dielectric can be measured by a BET adsorption method or a mercury porosimeter. In the examples described later, the porosity is measured using a dielectric fragment covered with a metallic base material by a mercury porosimeter manufactured by Shimadzu Corporation. High durability is achieved because the dielectric has a low porosity. Examples of the dielectric having such a void and a low void ratio include a high-density, high-adhesion ceramic spray coating by an atmospheric plasma spraying method described later. In order to further reduce the porosity, it is preferable to perform a sealing treatment.

  The above-mentioned atmospheric plasma spraying method is a technique in which fine powder such as ceramics, wire, or the like is put into a plasma heat source and sprayed onto a metallic base material to be coated as fine particles in a molten or semi-molten state to form a film. A plasma heat source is a high-temperature plasma gas in which a molecular gas is heated to a high temperature, dissociated into atoms, and energy is given to emit electrons. This plasma gas injection speed is high, and since the sprayed material collides with the metallic base material at a higher speed than conventional arc spraying or flame spraying, it is possible to obtain a coating film with high adhesion strength and high density. Specifically, reference can be made to a thermal spraying method for forming a heat shielding film on a high-temperature exposed member described in JP-A-2000-301655. By this method, the porosity of the dielectric (ceramic sprayed film) to be coated can be obtained.

  Another preferable specification that can withstand high power is that the thickness of the dielectric is 0.5 to 3 mm. The film thickness variation is desirably 5% or less, preferably 3% or less, and more preferably 1% or less.

In order to further reduce the porosity of the dielectric, it is preferable to further perform a sealing treatment with an inorganic compound on the sprayed film such as ceramics as described above. As the inorganic compound, a metal oxide is preferable, and among these, a compound containing silicon oxide (SiO _x ) as a main component is particularly preferable.

  The inorganic compound for sealing treatment is preferably formed by curing by a sol-gel reaction. In the case where the inorganic compound for sealing treatment contains a metal oxide as a main component, a metal alkoxide or the like is applied as a sealing liquid on the ceramic sprayed film and cured by a sol-gel reaction. When the inorganic compound is mainly composed of silica, it is preferable to use alkoxysilane as the sealing liquid.

  Here, it is preferable to use energy treatment for promoting the sol-gel reaction. Examples of the energy treatment include thermosetting (preferably 200 ° C. or lower), ultraviolet irradiation, and the like. Furthermore, as a method of sealing treatment, when the sealing liquid is diluted and coating and curing are sequentially repeated several times, the mineralization is further improved and a dense electrode without deterioration can be obtained.

When a ceramic sprayed coating is applied to a ceramic sprayed film using a metal alkoxide or the like of a dielectric-coated electrode as a sealing liquid, the content of the metal oxide after curing is 60 mol% or more when cured by a sol-gel reaction. Preferably there is. When alkoxysilane is used as the metal alkoxide of the sealing liquid, the content of SiO _x (x is 2 or less) after curing is preferably 60 mol% or more. The content of SiO _x after curing is measured by analyzing a fault of the dielectric layer by XPS.

  In the present invention, it is described in the present invention that the maximum height (Rmax) of the surface roughness defined by JIS B 0601: 2001 on the side in contact with at least the substrate of the electrode is adjusted to 10 μm or less. Although it is preferable from the viewpoint of obtaining an effect, the maximum value of the surface roughness is more preferably 8 μm or less, and particularly preferably adjusted to 7 μm or less. In this way, the dielectric surface of the dielectric-coated electrode can be polished to keep the dielectric thickness and the gap between the electrodes constant, the discharge state can be stabilized, and the heat shrinkage difference and residual Distortion and cracking due to stress can be eliminated, and durability can be greatly improved with high accuracy. The polishing finish of the dielectric surface is preferably performed at least on the dielectric in contact with the substrate. Further, the arithmetic average roughness (Ra) defined by JIS B 0601: 2001 is preferably 0.5 μm or less, and more preferably 0.1 μm or less.

  In the dielectric-coated electrode used in the present invention, another preferred specification that can withstand high power is that the heat-resistant temperature is 100 ° C. or higher. More preferably, it is 120 degreeC or more, Most preferably, it is 150 degreeC or more. The upper limit is 500 ° C. Note that the heat-resistant temperature refers to the highest temperature that can be withstood in a state in which dielectric breakdown does not occur and can be normally discharged. Such heat-resistant temperature can be applied by using the above-mentioned ceramic spraying or dielectric materials provided by layered glass linings with different amounts of bubbles, or within the range of the difference in linear thermal expansion coefficient between the metallic base material and the dielectric material below. This can be achieved by appropriately combining means for appropriately selecting the materials.

  In the present invention, it is necessary to employ an electrode capable of maintaining a uniform glow discharge state by applying such a voltage in a plasma discharge processing apparatus.

In the present invention, the power applied between the opposing electrodes supplies a power density of 1 to 50 W / cm ² to the second electrode, excites the discharge gas to generate plasma, and gives energy to the thin film forming gas. A thin film is formed. Preferably it is 1.2-30 W / cm < ² >.

  Here, regarding the method of applying the high frequency power source, either a continuous sine wave continuous oscillation mode called a continuous mode or an intermittent oscillation mode called ON / OFF intermittently called a pulse mode may be adopted. On the two-electrode side, a continuous sine wave is preferable because a denser and better quality film can be obtained.

Discharge conditions, the discharge space between the first electrode and the second electrode facing the high-frequency voltage is applied, the high frequency voltage, a first frequency omega ₁ of the voltage components higher than the first frequency omega ₁ It is preferable to have at least a component obtained by superimposing the voltage component of the second frequency ω ₂ .

The high-frequency voltage is a component obtained by superimposing the voltage component of the first frequency ω _{1 and} the voltage component of the second frequency ω ₂ higher than the first frequency ω ₁ , and the waveform is a sign of the frequency ω ₁ . The waveform is a sine wave of ω ₁ in which a sine wave of higher frequency ω ₂ is superimposed on the wave. It is not limited to a waveform in which a sine wave is superimposed, and both pulse waves may be used, one may be a sine wave and the other may be a pulse wave. Furthermore, it may have a third voltage component. However, in the present invention, as in the single-frequency high-frequency voltage application method, a continuous sine wave at least on the second electrode side can provide a denser and better quality film.

  In the present invention, the discharge start voltage refers to the lowest voltage that can cause discharge in the discharge space (electrode configuration, etc.) and reaction conditions (gas conditions, etc.) actually used. The discharge start voltage varies somewhat depending on the gas type supplied to the discharge space, the dielectric type of the electrode, and the like, but may be considered to be substantially the same as the discharge start voltage of the discharge gas alone.

  It is presumed that by applying a high-frequency voltage as described above between the counter electrodes (discharge space), discharge can be caused and high-density plasma can be generated.

In the present invention, a specific method for applying a high-frequency voltage to the discharge space is as follows: a first power source that applies a first high-frequency voltage having a frequency ω ₁ and a voltage V ₁ to the first electrode constituting the counter electrode. And a thin film forming apparatus (atmospheric pressure plasma processing apparatus) in which a second power source that applies a second high-frequency voltage having a frequency ω ₂ and a voltage V ₂ is connected to the second electrode.

Application of a high-frequency voltage from such two high-frequency power sources is necessary to start the discharge of the discharge gas having a high discharge start voltage on the first frequency ω ₁ side, and the second frequency ω _2. It is important that the side is necessary to increase the plasma density and form a dense and good quality thin film.

  In the present invention, it is preferable to apply a high frequency voltage of about 1 to 200 kHz from the first electrode using the first power source and a high frequency voltage of about 800 kHz to 15 MHz from the second electrode using the second power source. . In this case, the applied high-frequency voltage of 1 to 200 kHz excites a discharge gas having a high discharge start voltage to generate plasma.

  Furthermore, it is preferable that the first power source has a capability of applying a higher frequency voltage than the second power source.

As another discharge condition in the present invention, a high frequency voltage is applied between the opposed first electrode and second electrode, and the high frequency voltage is applied to the first high frequency voltage V ₁ and the second high frequency voltage. When V ₂ is superimposed and the discharge start voltage is IV,
V ₁ ≧ IV> V ₂
Or V ₁ > IV ≧ V ₂
Meet. More preferably,
V ₁ >IV> V ₂
Is to satisfy.

  The definition of the high frequency and the discharge start voltage and the specific method for applying the high frequency voltage between the counter electrodes (discharge space) are the same as those described above.

  Here, the high frequency voltage (applied voltage) and the discharge start voltage are those measured by the following method.

Measuring method of high-frequency voltages V ₁ and V ₂ (unit: kV / mm):
A high-frequency probe (P6015A) for each electrode part is installed, and the high-frequency probe is connected to an oscilloscope (Tektronix, TDS3012B) to measure the voltage.

Measuring method of discharge start voltage IV (unit: kV / mm):
A discharge gas is supplied between the electrodes, the voltage between the electrodes is increased, and a voltage at which discharge starts is defined as a discharge start voltage IV. The measuring instrument is the same as the above high-frequency voltage measurement.

  By adopting a discharge condition in which a high voltage is applied, even a discharge gas having a high discharge start voltage such as nitrogen gas can start the discharge gas and maintain a high density and stable plasma state.

When the discharge gas is nitrogen gas according to the above measurement, the discharge start voltage IV is about 3.7 kV / mm. Therefore, in the above relationship, the first high-frequency voltage is V ₁ ≧ 3.7 k.
By applying it as V / mm, nitrogen gas can be excited and put into a plasma state.

  The discharge gas includes noble gases such as nitrogen, helium and argon, air, hydrogen, oxygen and the like. These may be used alone as a discharge gas or mixed, but nitrogen gas should be used. However, it is particularly preferable because a high economic efficiency of the discharge gas can be obtained as compared with the case where a rare gas such as helium or argon is used.

  The high-frequency power source installed in the atmospheric pressure plasma processing apparatus is the same as that described above, but is divided into a first power source (high-frequency power source) and a second power source (high-frequency power source) as follows.

As the first power supply,
High frequency power supply code Manufacturer Frequency A1 Shinko Electric 3kHz
A2 Shinko Electric 5kHz
A3 Kasuga Electric 15kHz
A4 Shinko Electric 50kHz
A5 HEIDEN Laboratory 100kHz *
A6 Pearl Industry 200kHz
In addition, * mark is HEIDEN Laboratory impulse high frequency power supply (100 kHz in continuous mode).

As the second power source (high frequency power source),
High frequency power supply symbol Manufacturer Frequency B1 Pearl Industry 800kHz
B2 Pearl Industry 2MHz
B3 Pearl Industry 13.56MHz
B4 Pearl Industry 27MHz
B5 Pearl Industry 150MHz
And the like, and any of them can be preferably used.

  It is preferable that at least one of the counter electrodes includes a gas supply unit that supplies a discharge gas between the counter electrodes. Furthermore, it is preferable to have an electrode temperature control means for controlling the temperature of the electrode.

  Moreover, although the metal base material and the dielectric are not shown in the electrodes of FIGS. 6 and 7, it goes without saying that the same dielectric is coated on the metal base material of the electrodes as in FIGS. Absent.

  The high-frequency voltage applied between the counter electrodes may be an intermittent pulse wave or a continuous sine wave, but in order to obtain the effect of the present invention, it is a continuous sine wave. Is preferred.

  In the present invention, the distance between the electrodes is determined in consideration of the thickness of the dielectric disposed on the metal base material of the electrodes, the magnitude of the applied voltage, and the like. The shortest distance between the dielectric when the dielectric is placed on one of the electrodes and the distance between the dielectrics when the dielectric is placed on both of the electrodes 0.5 to 20 mm is preferable, more preferably 0.5 to 5 mm, still more preferably 0.5 to 3 mm, and particularly preferably 1 mm ± 0.5 mm.

  Each layer of the antireflection layer uses a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, a micro gravure coating method and an extrusion coating method on a transparent support. And can be formed by coating. At the time of coating, it is preferable that the transparent support is unwound in a roll shape with a width of 1.4 to 4 m, and is wound up in a roll shape after performing the above-described coating, drying and curing treatment. .

  Furthermore, the antireflection film of the present invention is preferably produced by a production method in which an antireflection layer or the like is laminated on a transparent support and then heat-treated at 50 to 160 ° C. while being wound up in a roll shape. The period of the heat treatment may be appropriately determined depending on the set temperature. For example, if it is 50 ° C., it preferably ranges from 3 days to less than 30 days, and if it is 160 ° C., it ranges from 10 minutes to 1 day. preferable. Usually, it is preferably set at a relatively low temperature so that the heat treatment effect at the outside of the winding, the center of the winding, and the core is not biased, and is preferably performed at around 50 to 60 ° C. for about 7 days.

  In order to stably perform the heat treatment, it is necessary to perform in a place where the temperature and humidity can be adjusted, and it is preferable to perform in a heat treatment chamber such as a clean room without dust.

  The winding core for winding the antireflection film into a roll is not particularly limited as long as it is a cylindrical core, but is preferably a hollow plastic core, and the plastic material is a heat resistant plastic that can withstand heat treatment temperatures. For example, resins such as phenol resin, xylene resin, melamine resin, polyester resin, and epoxy resin can be used. A thermosetting resin reinforced with a filler such as glass fiber is preferred.

  The number of windings on these winding cores is preferably 100 windings or more, more preferably 500 windings or more, and the winding thickness is preferably 5 cm or more.

  Thus, when the heat treatment is performed in a state where the long antireflection film is wound up, it is preferable to rotate the roll, and the rotation is preferably performed at a speed of 1 rotation or less per minute, even if it is continuous. It may be a good intermittent rotation. Moreover, it is preferable to perform rewinding of the roll once or more during the heating period.

  In order to rotate the long antireflection film wound around the core during the heat treatment, it is preferable to provide a dedicated turntable in the heat treatment chamber.

  In the case of intermittent rotation, it is preferable that the stop time is within 10 hours, the stop position is preferably made uniform in the circumferential direction, and the stop time is within 10 minutes. More preferred. Most preferred is continuous rotation.

  As for the rotation speed in continuous rotation, the time required for one rotation is preferably 10 hours or less, and if it is early, it becomes a burden on the apparatus, so the range of 15 minutes to 2 hours is substantially preferable.

  In the case of a dedicated carriage having a rotation function, it is preferable that the optical film roll can be rotated during movement and storage. In this case, rotation is effective as a countermeasure against black bands that occur when the storage period is long. Function.

〔Polarizer〕
A polarizing plate using the antireflection film of the present invention will be described.

  The polarizing plate can be produced by a general method. The back surface side of the antireflection film of the present invention is subjected to alkali saponification treatment, and a completely saponified polyvinyl alcohol aqueous solution is used on at least one surface of a polarizing film prepared by immersing and stretching the treated antireflection film in an iodine solution. It is preferable to bond them together. The antireflection film may be used on the other surface, or another polarizing plate protective film may be used. With respect to the antireflection film of the present invention, the polarizing plate protective film used on the other surface has an in-plane retardation Ro of 590 nm, an optical compensation film having a phase difference of 20 to 70 nm and Rt of 100 to 400 nm. A phase difference film). These can be prepared, for example, by the methods described in JP-A No. 2002-71957 and Japanese Patent Application No. 2002-155395. Alternatively, it is preferable to use a polarizing plate protective film that also serves as an optical compensation film having an optically anisotropic layer formed by aligning a liquid crystal compound such as a discotic liquid crystal. For example, the optically anisotropic layer can be formed by the method described in JP-A-2003-98348. By using in combination with the antireflection film of the present invention, a polarizing plate having excellent planarity and a stable viewing angle expansion effect can be obtained.

  As a polarizing plate protective film used on the back side, as a commercially available cellulose ester film, KC8UX2MW, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5 (manufactured by Konica Minolta Opto Co., Ltd.) Etc.) are preferably used.

  The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are ones in which iodine is dyed on a system film and ones in which a dichroic dye is dyed, but it is not limited to this. As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound. A polarizing film having a thickness of 5 to 30 μm, preferably 8 to 15 μm, is preferably used. On the surface of the polarizing film, one side of the antireflection film of the present invention is bonded to form a polarizing plate. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

(Image display device)
By incorporating the antireflection film surface of the polarizing plate using the antireflection film of the present invention into the viewing surface side of the image display device, various image display devices with excellent visibility can be produced. The antireflection film of the present invention is a reflection type, transmission type, transflective type LCD or LCD of various drive systems such as TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type), IPS type, etc. Preferably used. In addition, the antireflection film of the present invention has significantly less color unevenness in the reflected light of the antireflection layer, and has a low reflectance and excellent flatness, and is a plasma display, field emission display, organic EL display, inorganic EL display, electronic It is also preferably used for various display devices such as paper. In particular, an image display device having a large screen of 30 or more screens has an effect that there is little color unevenness and wavy unevenness, and eyes are not tired even during long-time viewing.

  Hereinafter, although an example is given and the present invention is explained, the present invention is not limited to this. Unless otherwise specified, “%” in the examples represents “mass%”.

Example 1
<< Preparation of antireflection film 1 >>
<Preparation of transparent support>
A transparent support of a transparent cellulose triacetate film (film thickness 80 μm, width 1330 mm) was produced as described below.

(Dope composition)
Cellulose triacetate (average degree of acetylation 61.0%) 100 parts by weight Triphenyl phosphate 8 parts by weight 2- [5-Chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (t-butyl ) Phenol 1 part by weight 2-[(2H) -benzotriazol-2-yl] -4,6-di-t-pentylphenol 1 part by weight Methylene chloride 430 parts by weight Methanol 90 parts by weight The above composition is put into a sealed container. The solution was kept at 80 ° C. under pressure and dissolved completely with stirring to obtain a dope composition.

  Next, the dope composition is filtered, cooled and kept at 33 ° C., and uniformly cast on a stainless steel band. After the solvent is evaporated until peeling becomes possible, the dope composition is peeled off from the stainless steel band. It was dried while being conveyed to obtain a transparent support having a film thickness of 80 μm.

  The surface in contact with the stainless steel band is defined as b-plane and the other surface is defined as a-plane. In addition, b side was used for hard-coat layer formation.

<Formation of hard coat layer>
The prepared transparent support was die-coated with the following hard coat layer coating solution with a coating width of 1.4 m, dried at 80 ° C., and then irradiated with 120 mJ / cm ² of ultraviolet light with a high-pressure mercury lamp to a film thickness after curing of 6 μm. A hard coat layer was provided.

(Hard coat layer coating solution)
Acetone 45 parts by weight Ethyl acetate 45 parts by weight PGME (propylene glycol monomethyl ether) 10 parts by weight Pentaerythritol triacrylate 30 parts by weight Pentaerythritol tetraacrylate 45 parts by weight Urethane acrylate (trade name U-4HA, manufactured by Shin-Nakamura Chemical Co., Ltd.) 25 1 part by mass 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals) 5 parts by mass 2-methyl-1- [4- (methylthio) phenyl] -2-monoforino-1-one (Irgacure 907, manufactured by Ciba Specialty Chemicals) 3 parts by weight BYK-331 (silicone surfactant, manufactured by Big Chemie Japan)
0.5 parts by mass of fluorine-containing polymethyl methacrylate fine particles (manufactured by Negami Kogyo), average particle size 3.5 μm
20 parts by mass
<Formation of back coat layer>
On the opposite side of the surface on which the hard coat layer was applied, the following back coat layer coating solution was die-coated so as to have a wet film thickness of 14 μm, dried at 85 ° C. and wound to provide a back coat layer.

(Coating solution for back coat layer)
Acetone 30 parts by mass Ethyl acetate 45 parts by mass Isopropyl alcohol 10 parts by mass Diacetyl cellulose 0.6 parts by mass Ultrafine silica 2% acetone dispersion (Aerosil 200V manufactured by Nippon Aerosil Co., Ltd.)
0.2 parts by mass <Atmospheric pressure plasma treatment>
The atmospheric pressure plasma treatment apparatus described in FIG. 7 of Japanese Patent Application No. 2005-351829 was used, and the following atmospheric pressure plasma treatment was performed on the hard coat layer surface.

The electrode gap is 0.5 mm, the discharge gas shown below is supplied to the discharge space, and a high frequency power source manufactured by Shinko Electric Co., Ltd. is used, the frequency is 13.5 MHz, the applied voltage Vp = 9.5 kV, and the output density is 1.5 W / Surface treatment was performed by forming a discharge as cm ² .

(Discharge gas)
Nitrogen gas 80.0% by volume
Oxygen gas 20.0% by volume
<Formation of high refractive index layer>
The surface of the hard coat layer is die-coated with the following high refractive index layer coating solution, dried at 80 ° C., and then irradiated with 120 mJ / cm ² of ultraviolet light with a high-pressure mercury lamp so that the cured film thickness becomes 110 nm. A high refractive index layer was provided. The refractive index of the high refractive index layer was 1.60.

(High refractive index layer coating solution)
PGME (propylene glycol monomethyl ether) 40 parts by mass Isopropyl alcohol 25 parts by mass Methyl ethyl ketone 25 parts by mass Pentaerythritol triacrylate 0.9 parts by mass Pentaerythritol tetraacrylate 1.0 part by mass Urethane acrylate (trade name: U-4HA, Shin Nakamura Chemical) 0.6 parts by mass Particle dispersion A (below) 20 parts by mass 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals) 0.4 parts by mass 2-methyl-1 -[4- (Methylthio) phenyl] -2-monoforinopropan-1-one (Irgacure 907, manufactured by Ciba Specialty Chemicals) 0.2 parts by mass FZ-2207 (10% propylene glycol monomethyl ether) Solution, manufactured by Nippon Unicar Co., Ltd.) 0.4 parts by mass (Preparation of particle dispersion A)
While stirring 12.0 kg of isopropyl alcohol in 6.0 kg of methanol-dispersed antimony double oxide colloid (solid content 60%, manufactured by Nissan Chemical Industries, Ltd., zinc antimonate sol, trade name: CELNAX CX-Z610M-F2) Gradually added to prepare a particle dispersion A.

<Formation of low refractive index layer>
The following low refractive index layer coating solution is die-coated on the high refractive index layer, dried at 80 ° C., and then irradiated with 120 mJ / cm ² of ultraviolet light with a high pressure mercury lamp so that the film thickness becomes 92 nm. An antireflection film 1 was prepared by providing a rate layer. The refractive index of the low refractive index layer was 1.38.

  The refractive index of the refractive index layer was obtained from the measurement result of the spectral reflectance of the spectrophotometer. The spectrophotometer uses U-4000 type (manufactured by Hitachi, Ltd.), and after roughening the back side of the measurement side of the sample, light absorption treatment is performed with a black spray to prevent reflection of light on the back side. The reflectance in the visible light region (400 to 700 nm) was measured under the condition of regular reflection at 5 degrees.

(Low refractive index layer coating solution)
Propylene glycol monomethyl ether 430 parts by mass Isopropyl alcohol 430 parts by mass Tetraethoxysilane hydrolyzate A (following, solid content 21% conversion) 120 parts by mass γ-methacryloxypropyltrimethoxysilane (trade name: KBM503, Shin-Etsu Chemical Co., Ltd.) Product) 3.0 parts by mass Isopropyl alcohol-dispersed hollow silica fine particles 1 (below, solid content 20%, average particle size 45 nm, particle size variation coefficient 30%) 40 parts by mass Aluminum ethyl acetoacetate diisopropylate (Kawaken Fine Chemical) ALCH) 3.0 parts by mass FZ-2207 (10% propylene glycol monomethyl ether solution, manufactured by Nihon Unicar) 3.0 parts by mass (Preparation of tetraethoxysilane hydrolyzate A)
After mixing 230 g of tetraethoxysilane (trade name: KBE04, manufactured by Shin-Etsu Chemical Co., Ltd.) and 440 g of ethanol and adding 120 g of a 2% aqueous acetic acid solution thereto, the mixture is stirred for 28 hours at room temperature (25 ° C.). Silane hydrolyzate A was prepared.

(Preparation of isopropyl alcohol-dispersed hollow silica fine particles 1)
A mixture of 100 g of silica sol having an average particle diameter of 5 nm and a SiO ₂ concentration of 20% by mass and 1900 g of pure water was heated to 80 ° C. The pH of this reaction mother liquor was 10.5, and 9000 g of 0.98 mass% sodium silicate aqueous solution as SiO ₂ and 9000 g of 1.02 mass% sodium aluminate aqueous solution as Al ₂ O ₃ were simultaneously added to the mother liquor. did. Meanwhile, the temperature of the reaction solution was kept at 80 ° C. The pH of the reaction solution rose to 12.5 immediately after the addition and hardly changed thereafter. After completion of the addition, the reaction solution was cooled to room temperature and washed with an ultrafiltration membrane to prepare a SiO ₂ .Al ₂ O ₃ core particle dispersion having a solid content concentration of 20% by mass. (Process (a))
1700 g of pure water is added to 500 g of this core particle dispersion and heated to 98 ° C., and while maintaining this temperature, a silicic acid solution (SiO ₂₎ obtained by dealkalizing a sodium silicate aqueous solution with a cation exchange resin. A dispersion of core particles in which 3000 g (concentration of 3.5% by mass) was added to form a first silica coating layer was obtained. (Process (b))
Next, 1125 g of pure water is added to 500 g of the core particle dispersion liquid that has been washed with an ultrafiltration membrane to form a first silica coating layer having a solid concentration of 13% by mass, and concentrated hydrochloric acid (35.5%) is further added dropwise. The pH was adjusted to 1.0 and dealumination was performed. Next, the aluminum salt dissolved in the ultrafiltration membrane was separated while adding 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water, and SiO ₂ · Al from which some of the constituent components of the core particles forming the first silica coating layer were removed. A dispersion of ₂ O ₃ porous particles was prepared (step (c)). A mixture of 1500 g of the above porous particle dispersion, 500 g of pure water, 1,750 g of ethanol, and 626 g of 28% ammonia water is heated to 35 ° C., and then 104 g of ethyl silicate (SiO ₂ 28 mass%) is added. The surface of the porous particles on which the first silica coating layer was formed was coated with a hydrolyzed polycondensate of ethyl silicate to form a second silica coating layer. Next, a dispersion of hollow silica-based fine particles 1 having a solid content concentration of 20% by mass was prepared by replacing the solvent with isopropyl alcohol using an ultrafiltration membrane.

The thickness of the first silica coating layer of the hollow silica-based fine particles was 3 nm, the average particle size was 45 nm, MOx / SiO ₂ (molar ratio) was 0.0017, and the refractive index was 1.28. Here, the average particle diameter and the coefficient of variation of the particle diameter were measured by a dynamic light scattering method.

<< Preparation of antireflection film 2 >>
In the production of the antireflection film 1, the amount of the isopropyl alcohol-dispersed hollow silica-based fine particles 1 in the low refractive index layer coating solution was changed to 120 parts by mass, and the antireflection film 2 was produced in the same manner.

<< Preparation of antireflection film 3 >>
In the production of the antireflection film 1, the following was further added to the coating solution for the low refractive index layer, and the antireflection film 3 was produced in the same manner as the others.

Isopropyl alcohol-dispersed spherical colloidal silica 1 (solid content 20%, average particle size 20 nm, particle size variation coefficient 30%, commercially available product) 80 parts by mass << Preparation of antireflection film 4 >>
In the production of the antireflection film 1, the following was further added to the coating solution for the low refractive index layer, and the antireflection film 4 was produced in the same manner as the others.

Isopropyl alcohol-dispersed spherical colloidal silica 2 (solid content 20%, average particle size 45 nm, particle size variation coefficient 30%, commercially available product) 80 parts by mass << Preparation of antireflection film 5 >>
In the production of the antireflection film 1, the following was further added to the coating solution for the low refractive index layer, and the antireflection film 5 was produced in the same manner as others.

Isopropyl alcohol-dispersed spherical colloidal silica 3 (solid content 20%, average particle size 90 nm, particle size variation coefficient 30%, commercially available product) 20 parts by mass << Preparation of antireflection film 6 >>
In the production of the antireflection film 5, the amount of the isopropyl alcohol-dispersed spherical colloidal silica 3 in the low refractive index layer coating solution was changed to 80 parts by mass, and the others were similarly produced.

<< Preparation of antireflection film 7 >>
In the production of the antireflection film 5, the amount of the isopropyl alcohol-dispersed spherical colloidal silica 3 in the low refractive index layer coating solution was changed to 140 parts by mass, and the antireflection film 7 was produced in the same manner.

<< Preparation of antireflection film 8 >>
In the production of the antireflection film 1, the following was further added to the coating solution for the low refractive index layer, and an antireflection film 8 was produced in the same manner as others.

Isopropyl alcohol-dispersed spherical colloidal silica 4 (solid content 20%, average particle size 200 nm, particle size variation coefficient 30%, commercially available product) 80 parts by mass << Preparation of antireflection film 9 >>
In the production of the antireflection film 1, the following was further added to the coating solution for the low refractive index layer, and an antireflection film 9 was produced in the same manner as others.

Isopropyl alcohol-dispersed spherical colloidal silica 5 (solid content 20%, average particle size 9500 nm, particle size variation coefficient 30%, commercially available product) 80 parts by mass << Preparation of antireflection film 10 >>
In the production of the antireflection film 6, the isopropyl alcohol-dispersed hollow silica fine particles 1 and the isopropyl alcohol-dispersed spherical colloidal silica 3 in the low refractive index layer coating solution were changed to the following, and the antireflection film 9 was produced in the same manner. .

Isopropyl alcohol-dispersed hollow silica-based fine particles 2 (prepared by adjusting the production conditions of the above-mentioned isopropyl alcohol-dispersed hollow silica-based fine particles 1 with a solid content of 20%, an average particle size of 45 nm, a particle size variation coefficient of 10%, and 40 parts by mass of isopropyl Alcohol-dispersed spherical colloidal silica 6 (solid content 20%, average particle size 90 nm, particle size variation coefficient 10%, commercial product) 80 parts by mass << Preparation of antireflection film 11 >>
In the production of the antireflection film 6, the following was further added to the coating solution for the low refractive index layer, and the antireflection film 11 was produced in the same manner as the others.

Isopropyl alcohol-dispersed acicular colloidal silica 7 (solid content 20%, average particle size 90 nm, particle size variation coefficient 50%, commercially available product) 40 parts by mass << Preparation of antireflection film 12 >>
In the production of the antireflection film 6, the antireflection film 12 was produced in the same manner except that the PMMA fine particles were removed from the hard coat layer coating solution.

<Evaluation of antireflection film>
The produced antireflection film was evaluated for reflectivity and scratch resistance as follows.

(Reflectance)
In order to prevent back surface reflection, the sample was affixed on a black acrylic plate with a substrate-less double-sided tape, and the reflectance was measured with SPECTROPHOMETER CM-2500d manufactured by Minolta.

(Abrasion)
A sample was subjected to a load of 250 g / cm ^{2 on} # 0000 steel wool (SW) in an environment of 23 ° C. and 55% RH, and the number of scratches per 1 cm width was measured after 10 reciprocations. In addition, the number of scratches is measured at a place where the number of scratches is the largest among the portions where the load is applied. If it is 10 / cm or less, there is no practical problem, but 5 / cm or less is preferable, and 3 / cm or less is more preferable.

  The evaluation results are shown in Table 1.

  From the table, it can be seen that the sample of the present invention is improved in both reflectance and scratch resistance. It can be seen that a larger amount of colloidal silica is preferable and a larger particle size is preferable.

Example 2
<< Preparation of antireflection film 13 >>
In the production of the antireflection film 6 of Example 1, the atmospheric pressure plasma treatment was not performed on the surface of the hard coat layer, and an antireflection film 13 was produced in the same manner except that.

<< Preparation of antireflection film 14 >>
In the production of the antireflection film 6 of Example 1, the antireflection film 14 was produced in the same manner except that the PMMA fine particles in the hard coat layer coating solution were changed to those having an average particle diameter of 2 μm.

<< Preparation of antireflection film 15 >>
In the production of the antireflection film 12 of Example 1, the hard coat layer coating solution was die-coated and temporarily dried at 50 ° C., then the surface of the hard coat layer was embossed with a roll with protrusions, and then the film was heated at 80 ° C. The antireflection film 15 was produced in the same manner as above except for drying.

<< Preparation of antireflection film 16 >>
In the production of the antireflection film 12 of Example 1, the dope composition was cast on a stainless steel band, and after the solvent was evaporated, the roll was peeled off from the stainless steel band, and then the surface of the transparent support b surface was provided with a protrusion. The antireflection film 16 was produced in the same manner as described above.

<Evaluation of antireflection film>
About the produced anti-reflective film, together with the anti-reflective films 6 and 12 produced in Example 1, it is reflected as an index of arithmetic mean roughness and visibility when used in a display device as follows, and sharp And transmission image clarity were evaluated.

(Arithmetic mean roughness)
According to JIS B 0601: 2001, using an optical interference type surface roughness meter RST / PLUS (manufactured by WYKO), each surface of the transparent support (b surface), the hard coat layer and the antireflection film is 1.2 mm. Arithmetic mean roughness was determined for an area of × 0.9 mm.

(Reflection, sharpness)
Each sample was affixed on a monitor with a substrate-less double-sided tape, and 30 persons performed image sensory and sensory evaluation of sharpness, and the average score was obtained. Ten points are the best, with little reflection or high sharpness. One point is the worst. Five or more points are acceptable levels.

(Transparency mapping)
The transmission image clarity at a comb width of 2.5 mm was measured with a image clarity measuring device ICM-IDP of Suga Test Instruments Co., Ltd. Transmission image clarity is a parameter that correlates with sharpness.

  The evaluation results are shown in Table 2.

  From the table, the antireflection films 6 and 13 to 16 corresponding to any one of claims 2 to 4 correspond to claim 1 but also to any of claims 2 to 4. Compared with the antireflection film 12 which does not correspond, the reflection on the screen is small and good, and the antireflection film 14 which does not fall within the scope of claim 3 and the antireflection film which has not been subjected to atmospheric pressure plasma treatment on the hard coat layer surface It turns out that 13 is somewhat inferior. Further, the antireflection film 12 that falls under claim 1 but does not fall under claim 2 is considerably inferior. It can be seen that the antireflection film 16 corresponding to claim 4 is as good as the antireflection film 12 in sharpness and transmission image clarity.

Claims (4)

In an antireflection film having at least a low refractive index layer on a transparent support directly or via another layer, the low refractive index layer contains at least two types of silica fine particles, and one type of silica fine particles is contained inside Is a hollow silica-based fine particle having a porous or hollow shape, and the other one type of silica fine particle is colloidal silica, and the average particle size of the colloidal silica is 1.1 to 20 of the average particle size of the hollow silica-based fine particle. An antireflection film having an arithmetic average roughness (Ra) of an outermost surface of less than 40 times and less than 40 to 500 nm. The hard coat layer and the low refractive index layer are provided on the transparent support, and the arithmetic average roughness (Ra) of the surface of the hard coat layer is less than 60 to 700 nm. The antireflection film as described. 3. The antireflection film according to claim 1, wherein an arithmetic average roughness (Ra) of the surface of the transparent support is less than 50 to 1000 nm. 4. The antireflection film according to claim 1, wherein the hard coat layer contains fluorine-containing acrylic resin fine particles. 5.