JP2006113561A - Producing method of light-scattering film, polarizing plate comprising light-scattering film and liquid crystal display device comprising the polarizing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a producing method capable of producing a light-scattering film or an antireflection film excellent in uniformity of light-scattering property in the surface of broad width sample and to provide a polarizing plate and a display device using the light-scattering film and the antireflection film produced by the producing method. <P>SOLUTION: In the producing method of light scattering film, a light-scattering layer is applied on a transparent support as follow: a land 18 of a forward end lip 17 of a slot die 13 is disposed close to the surface of a web W, and a coating composition 14 is applied on the web W through a slot 16 of the forward end lip 17, wherein the web W is supported by a backup roller 11 and, at the same time, runs continuously, and wherein the coating composition 14 comprises a light-transmitting fine particle, a light-transmitting resin and a solvent, and the coating composition satisfies the relation (1); (σ-ρ)×d<SP>2</SP>≤1.5 (1), wherein σ is density (g/cm<SP>2</SP>) of the light-transmitting fine particle, ρ is density (g/cm<SP>2</SP>) of the coating composition and (d) is average particle size (μm) of the light-transmitting fine particle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a light-scattering film, and more specifically, a film surface on which high productivity can be realized by applying a coating composition with controlled sedimentation of translucent fine particles using a die coater. It is related with the manufacturing method of the light-scattering film which has a uniform scattering property in the inside. The present invention also relates to a polarizing plate using the light scattering film and a liquid crystal display device using the polarizing plate.

  The light scattering film is roughly classified into an antiglare film having a surface scattering property and an internal scattering film having a scattering property only inside. Antiglare films are generally used in display devices such as CRT, plasma display (PDP), electroluminescence display (ELD) and liquid crystal display (LCD) to prevent reflection of images due to reflection of external light. Arranged on the outermost surface of the display. In addition, as a means for improving minute brightness unevenness (referred to as glare) due to the anti-glare film in recent years, especially with the increase in the definition of display devices, there is a technique related to an anti-glare film having internal scattering in addition to surface scattering. (Patent Documents 1 to 5).

  On the other hand, there is disclosed a technique relating to a scattering film that improves the viewing angle characteristics of an LCD by having only surface scattering and not internal scattering (Patent Document 6). Further, as disclosed in Patent Documents 6 and 7, etc., when a light scattering film is used on the outermost surface of the display device, the reflection has an effect of suppressing surface reflection of external light in a bright room. It is known that a film having a prevention function is preferable.

  The light scattering film as described above has been conventionally produced by using a bar coating method, a gravure method, a micro gravure method, etc., but in recent years, a relatively wet coating amount capable of achieving higher productivity. A technique relating to a die coating method that can be suitably used in a region having a small amount is disclosed in Patent Document 8 and the like.

  However, in the coating composition for the light scattering layer disclosed in the above-mentioned patent document, translucent fine particles accumulate in the pockets inside the die coater or are discharged in the width direction of the slot when applied by the die coating method. Unevenness in the surface of the light-scattering film due to the non-uniform density of the light-transmitting fine particles in the coating composition is a problem, and countermeasures have been difficult.

JP 2000-304648 A Japanese Patent No. 3507719 Japanese Patent Laid-Open No. 11-3276608 Japanese Patent No. 3515401 Japanese Patent No. 3515426 JP 2003-121606 A JP 2003-270409 A JP 2003-236434 A

In short, the present situation is that no method for producing a light-scattering film having a uniform scattering property in the film plane by a die coating method that satisfies high productivity has been proposed.
Accordingly, an object of the present invention is to produce a light scattering film having a uniform scattering property in the film plane, and further to produce an antireflection film with high productivity.

As a result of intensive studies to solve the above-mentioned problems, the present inventors consider that the cause of the problem is that the sedimentation rate of the translucent fine particles is too high, and the sedimentation rate of the translucent microparticles in the coating composition. It is found that the above-mentioned problems can be solved and the object can be achieved by adjusting the density of the light-transmitting fine particles, the density of the coating composition, and the average particle size factor of the light-transmitting fine particles. It came to complete.
That is, the present invention achieves the object by the following configuration.

[1]
In the method for producing a light scattering film having a light scattering layer on a transparent support,
A coating composition for the light scattering layer, comprising translucent fine particles, a translucent resin, and a solvent, wherein the settling rate of the translucent fine particles is controlled by satisfying the formula (1) The light scattering layer is coated on the transparent support by applying the composition from the slot of the tip lip of the slot die in close proximity to the surface of a continuously running web supported by a backup roll. The manufacturing method of the light-scattering film characterized by including the process to apply.
Formula (1) (σ−ρ) × d ² ≦ 1.5
(Where, σ: density of translucent fine particles (g / cm ² ), ρ: density of coating composition (g / cm ² ), d: average particle diameter of translucent fine particles (μm))
[2]
In the said coating composition, when the said translucent fine particle swells with the said solvent, (sigma), (rho), and d after swelling satisfy | fill said Formula (1), It is characterized by the above-mentioned. A method for producing a light-scattering film.
[3]
The translucent fine particles have an average particle diameter of 0.5 to 5 μm, the difference in refractive index between the translucent fine particles and the translucent resin is 0.01 to 0.2, and the translucency The method for producing a light-scattering film according to [1] or [2], wherein fine particles are contained in an amount of 3 to 30% by mass in the total solid content of the light-scattering layer.
[4]
The translucent fine particles are crosslinked polystyrene, crosslinked poly (acryl-styrene), crosslinked poly ((meth) acrylate), or a mixture thereof, and the solvent is at least one selected from ketones, toluene, xylene, and esters. It consists of a kind of solvent, The manufacturing method of the light-scattering film in any one of [1]-[3] characterized by the above-mentioned.
[5]
The light scattering film is an antireflection film in which a low refractive index layer having a refractive index lower than that of the support is formed on the light scattering layer directly or via another layer. The manufacturing method of the light-scattering film in any one of [1]-[4].
[6]
By applying the land of the tip lip of the slot die close to the surface of the web supported by the backup roll and continuously running from the slot of the tip lip, on the transparent support, the light scattering layer, In the method for producing a light-scattering film in which a low refractive index layer or other layer is applied,
A slot die having a land length at a tip lip on the web traveling direction side of the slot die of 30 μm or more and 100 μm or less, and when the slot die is installed at a coating position, It is applied using a slot die having an overbite shape such that the gap between the tip lip opposite to the web traveling direction and the gap between the web and the web is smaller by 30 μm or more and 120 μm or less [1] The manufacturing method of the light-scattering film in any one of-[5].
[7]
In the polarizing plate formed by laminating a polarizing film and two protective films for protecting both the front side and the back side of the polarizing film, the polarizing film was produced by the production method according to any one of [1] to [6]. A polarizing plate using a light scattering film as a protective film on one side.
[8]
Of the two protective films for forming the polarizing plate, the film other than the light-scattering film includes an optically anisotropic layer on the surface opposite to the surface to be bonded to the polarizing film. An optical compensation film having an optical compensation layer, wherein the optical anisotropic layer is a layer made of a compound having a discotic structural unit, and the disc surface of the discotic structural unit is inclined with respect to the protective film surface. And the angle formed by the disc surface of the discotic structural unit and the surface of the protective film varies in the depth direction of the optically anisotropic layer. .
[9]
It has a light-scattering film manufactured with the manufacturing method in any one of [1]-[6], The image display apparatus characterized by the above-mentioned.
[10]
A liquid crystal display device comprising at least one light-scattering film produced by the production method according to any one of [1] to [6] or the polarizing plate according to claim 7 or 8.
[11]
The liquid crystal cell according to any one of [1] to [6], having a polarizer on both surfaces of the liquid crystal cell, and having at least one phase difference compensation element between the liquid crystal cell and the polarizer. It has a light-scattering film manufactured with the manufacturing method, The liquid crystal display device characterized by the above-mentioned.

  The method for producing a light-scattering film of the present invention allows the density of the light-transmitting fine particles, the density of the coating composition, By applying a coating composition containing translucent fine particles, a translucent resin, and a solvent adjusted by paying attention to the factor of the average particle diameter of the light fine particles, to the surface of the transparent support by a die coating method, Even by a die coating method that satisfies high productivity, it was possible to provide a method for producing a light-scattering film having no unevenness in the light-scattering film surface and having uniform scattering properties in the film surface.

  Hereinafter, the present invention will be described in more detail. In the present specification, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”. . Moreover, in this specification, description with "(meth) acrylate" represents the meaning of "at least one of an acrylate and a methacrylate." The same applies to “(meth) acrylic acid” and the like.

A basic configuration of a preferred embodiment of a light-scattering film produced by the production method of the present invention (hereinafter also referred to as “light-scattering film of the present invention”) will be described with reference to the drawings.
Here, FIG. 1 is a cross-sectional view schematically showing a preferred embodiment of the light-scattering film of the present invention. Although FIG. 1 shows an example of antiglare property having surface irregularities, a light scattering film not having antiglare properties having no surface irregularities is also preferably used.
A light scattering film 1 according to this embodiment shown in FIG. 1 includes a transparent support 2, a light scattering layer 3 formed on the transparent support 2, and a low refractive index layer formed on the light scattering layer 3. It consists of four. Forming a low refractive index layer on the light scattering layer with a film thickness of about ¼ of the wavelength of light is more preferable because surface reflection can be reduced by the principle of thin film interference.
The light scattering layer 3 includes a translucent resin and translucent fine particles 5 dispersed in the translucent resin.
The refractive index of each layer constituting the light-scattering film having an antireflection layer in the present invention preferably satisfies the following relationship.
Refractive index of light scattering layer> refractive index of transparent support> refractive index of low refractive index layer In the present invention, the light scattering layer preferably has antiglare properties and / or hard coat properties. In FIG. 1, although formed by one layer is illustrated, it may be composed of a plurality of layers, for example, two to four layers. Moreover, although you may provide directly on a transparent support body like this embodiment, you may provide via other layers, such as an antistatic layer and a moisture-proof layer.

When the anti-glare property is imparted to the light-scattering film of the present invention, the center line average roughness Ra is 0.08 to 0.40 μm and the 10-point average roughness Rz is 10 times or less of Ra as the surface irregularity shape. The average deviation between the peaks and valleys Sm is 1 to 100 μm, the standard deviation of the height of the convex part from the deepest part of the irregularities is 0.5 μm or less, the standard deviation of the average mountain valley distance Sm based on the center line is 20 μm or less, and the inclination angle is 0 to 5 It is preferable to design so that the degree of surface is 10% or more because sufficient anti-glare property and visual uniform mat feeling can be achieved.
Further, the minimum reflectance of the reflected light in the CIE 1976 L ^* a ^* b ^* color space under the C light source is in the range of a ^* value −2 to 2, b ^* value −3 to 3, 380 nm to 780 nm. A ratio between the value and the maximum value of 0.5 to 0.99 is preferable because the color of the reflected light becomes neutral. Moreover, when the b ^* value of the transmitted light under the C light source is set to 0 to 3, the yellow color of white display when applied to a display device is reduced, which is preferable. In addition, when a 120 μm × 40 μm grid is inserted between the surface light source and the antireflection film of the present invention and the luminance distribution is measured on the film, the standard deviation of the luminance distribution is set to 20 or less. The glare when the film of the invention is applied is reduced, which is preferable.

  On the other hand, the light scattering film having only the internal scattering property of the present invention preferably has a center line average roughness Ra of 0.10 or less as its surface irregularity shape, and has substantially no antiglare property. . Since there are many regions with different refractive indexes inside the light scattering layer, it has internal scattering properties, so that the effect of improving viewing angle characteristics when applied to the outermost surface of a liquid crystal display device can be obtained. It is preferred to optimize the scattering properties.

  Further, the light scattering film having the antireflection layer of the present invention has an optical characteristic of a specular reflectance of 2.5% or less and a transmittance of 90% or more. Is preferable. The haze is preferably 1% to 60%, more preferably 20% to 60%, and particularly preferably 20% to 50%. Internal haze / total haze value of 0.3 to 1, lowering of haze value after formation of low refractive index layer from haze value to light scattering layer within 15%, transmitted image sharpness at comb width of 0.5 mm 10% to 70% vertical transmission light / transmission ratio in the direction of 2 degrees tilt from vertical is 1.5 to 5.0, which prevents glare on a high-definition LCD panel and reduces blurring of characters, etc. Therefore, it is preferable. In addition, when not aiming at provision of anti-glare property, 65-99% of transmitted image definition is used preferably.

Next, the light scattering layer will be described below.
<Light scattering layer>
The light scattering layer is formed for the purpose of contributing to the film light diffusibility due to surface scattering and / or internal scattering, and preferably hard coat properties for improving the scratch resistance of the film. Therefore, it preferably contains a translucent resin capable of imparting hard coat properties, translucent fine particles for imparting light diffusibility, and a solvent as essential components. Further, by controlling the sedimentation rate of the light-transmitting fine particles by satisfying the above formula (1), coating can be performed on the transparent support with high in-plane uniformity by a die coating method having high productivity. It becomes possible. The left side of the above formula (1) is a term relating to the density, particle size and density of the coating composition in the sedimentation velocity formula (2) of the particles in the fluid derived from the Stokes formula. When it is 1.5 or less, it becomes easy to avoid the above-mentioned various troubles caused by the sedimentation rate of the translucent fine particles being too high in the coating step by the die coating method, preferably 1.0 or less, more preferably 0 .5 or less is more preferable. When this value is negative, the translucent fine particles become a floating substance after a long time, but this is not a big problem when continuously fed, but it is preferably close to zero.
In addition to the above, the viscosity of the coating composition can be cited as a factor for controlling the sedimentation rate of the light-transmitting fine particles. From the viewpoint of the sedimentation rate, a higher viscosity is preferable, but the viscosity of the coating composition is from the viewpoint of high-speed coating suitability. 20 × 10 ⁻³ (Pa · s) or less, preferably 15 × 10 ⁻³ (Pa · s) or less, and more preferably 10 × 10 ⁻³ (Pa · s) or less. From the viewpoint of preventing drying unevenness, 1 × 10 ⁻³ (Pa · s) or more is preferable, 3 × 10 ⁻³ (Pa · s) or more is particularly preferable, and 5 × 10 ⁻³ (Pa · s) or more is particularly preferable. . 3-15 × 10 ⁻³ (Pa · s) is preferable in order to control the particle sedimentation property while achieving both high-speed application suitability and drying unevenness, and 5 to 10 × 10 ⁻³ (Pa · s) is particularly preferable. preferable.

Formula (2) Sedimentation velocity Vs = (1/18) × (σ−ρ) × (g / μ) × d ²
(Where, σ: density of translucent fine particles (g / cm ² ), ρ: density of coating composition (g / cm ² ), g: acceleration of gravity, d: average particle diameter of translucent fine particles (μm) , Μ: Viscosity of coating composition (Pa · s))

  In the coating composition for forming the light-scattering film of the present invention, when the light-transmitting fine particles are swollen to some extent by the solvent, the density of the light-transmitting fine particles and the density of the coating composition are apparently close to each other. Since the absolute value of (σ−ρ) in 1) is small, the sedimentation (floating) speed is slow, which is preferable. As a combination in which the light-transmitting fine particles are easily swollen by a solvent, the light-transmitting fine particles are cross-linked polystyrene, cross-linked poly (acryl-styrene), cross-linked poly ((meth) acrylate), or a mixture thereof, and the solvent is a ketone. It is preferably composed of at least one solvent selected from toluene, xylene and esters. The swelling of the light-transmitting fine particles can be controlled by the crosslinking density of the particles, and can be adjusted by a combination with the solvent used.

<Translucent fine particles>
The average particle diameter of the translucent fine particles is preferably 0.5 to 5 μm, more preferably 1.0 to 4.0 μm. If the average particle size is less than 0.5 μm, the light scattering angle distribution spreads to a wide angle, which causes a decrease in character resolution of the display, which is not preferable. On the other hand, if it exceeds 5 μm, the absolute value of the above formula (1) becomes too large, so that the sedimentation speed becomes fast, it is necessary to increase the thickness of the light scattering layer, the curl becomes large, and the material cost increases. Problems occur.
Specific examples of the translucent fine particles are not particularly limited as long as they are coating compositions satisfying the relationship of the formula (1). For example, particles of inorganic compounds such as silica particles and TiO ₂ particles; poly ((meth) acrylates ) Particles, cross-linked poly ((meth) acrylate) particles, polystyrene particles, cross-linked polystyrene particles, cross-linked poly (acryl-styrene) particles, melamine resin particles, benzoguanamine resin particles and the like are preferred, but generally inorganic Since the specific gravity of the particles is large, it is not preferable to use them, and resin particles are preferably used. Of these, crosslinked polystyrene particles, crosslinked poly ((meth) acrylate) particles, and crosslinked poly (acryl-styrene) particles are preferable.
The shape of the translucent fine particles is preferably spherical. An indefinite shape can be used, but since the shape factor in the sedimentation velocity formula is different from that of a sphere, the preferred range on the left side of the formula (1) is different for each shape.

  Further, two or more kinds of translucent fine particles having different particle diameters may be used in combination. It is possible to impart an antiglare property with a light-transmitting fine particle having a larger particle size and to impart another optical characteristic with a light-transmitting fine particle having a smaller particle size. For example, when an antireflection film is attached to a high-definition display of 133 ppi or higher, it is required that there is no problem in optical performance called glare as described above. Glare originates from the fact that pixels are enlarged or reduced due to unevenness existing on the film surface (contributing to anti-glare properties), resulting in loss of brightness uniformity, but smaller particles than translucent fine particles that impart anti-glare properties. The diameter can be greatly improved by using light-transmitting fine particles different from the refractive index of the binder.

The translucent fine particles are blended in the formed light scattering layer so as to be contained in an amount of 3 to 30% by mass in the total solid content of the light scattering layer. More preferably, it is 5-20 mass%. When the amount is less than 3% by mass, the light scattering effect is insufficient, and when it exceeds 30% by mass, problems such as a reduction in image resolution, surface turbidity and glare occur.
Moreover, the density of the translucent fine particles is preferably 10 to 1000 mg / m ² , more preferably 100 to 700 mg / m ² .
The particle size distribution of the translucent fine particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution.

The bulk refractive index of the mixture of the translucent resin and translucent fine particles in the present invention is preferably 1.48 to 2.00, more preferably 1.50 to 1.80. In order to set the refractive index within the above range, the kind and amount ratio of the light-transmitting resin and the light-transmitting fine particles may be appropriately selected. How to select can be easily known experimentally in advance.
In the present invention, the difference in refractive index between the translucent resin and the translucent fine particles (the refractive index of the translucent fine particles−the refractive index of the translucent resin) is preferably 0.01 to 0.2. More preferably, it is 0.02-0.2, More preferably, it is 0.05-0.15. If this difference is less than 0.02, the effect of internal scattering is insufficient and the glare deteriorates. If it exceeds 0.2, the problem of cloudiness on the film surface arises.
The refractive index of the translucent resin is preferably 1.45 to 2.00, and more preferably 1.48 to 1.60.
The refractive index of the translucent fine particles is preferably 1.40 to 1.80, more preferably 1.48 to 1.70.
Here, the refractive index of the translucent resin can be quantitatively evaluated by directly measuring the refractive index with an Abbe refractometer or by measuring a spectral reflection spectrum or a spectral ellipsometry.

  The film thickness of the light scattering layer is preferably 1 to 10 μm, and more preferably 1.2 to 8 μm. If it is too thin, the hard property is insufficient, and if it is too thick, curling and brittleness may be deteriorated and workability may be lowered.

<Translucent resin>
The translucent resin is preferably a binder polymer having a saturated hydrocarbon chain or a polyether chain as a main chain, and more preferably a binder polymer having a saturated hydrocarbon chain as a main chain. The binder polymer preferably has a crosslinked structure.
As the binder polymer having a saturated hydrocarbon chain as a main chain, a polymer of an ethylenically unsaturated monomer is preferable. As the binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure, a (co) polymer of monomers having two or more ethylenically unsaturated groups is preferable.
In order to increase the refractive index of the binder polymer, the monomer structure has a high refractive index including at least one atom selected from an aromatic ring, a halogen atom other than fluorine, a sulfur atom, a phosphorus atom, and a nitrogen atom. The rate monomer can also be selected.

  Examples of the monomer having two or more ethylenically unsaturated groups include esters of polyhydric alcohol and (meth) acrylic acid [for example, ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di ( (Meth) acrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (Meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3- Chlorohexane tetramethacrylate, polyurethane polyacrylate, polyester polyacrylate], modified ethylene oxide of the above ester, vinylbenzene and derivatives thereof (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone], vinylsulfone (eg, divinylsulfone), acrylamide (eg, methylenebisacrylamide) and methacrylamide. Two or more of these monomers may be used in combination.

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

Polymerization of the monomer having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator.
Therefore, the light scattering layer is composed of a monomer for forming a translucent resin such as the above-mentioned ethylenically unsaturated monomer, a photo radical initiator or a thermal radical initiator, translucent fine particles, and an inorganic material as described later if necessary. It can be formed by preparing a coating liquid containing a filler and curing the coating liquid on a transparent support by ionizing radiation or a polymerization reaction with heat.

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

As the thermal radical initiator, organic or inorganic peroxides, organic azo, diazo compounds, and the like can be used.
Specifically, benzoyl peroxide, halogen benzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide, butyl hydroperoxide as organic peroxides, hydrogen peroxide, peroxides as inorganic peroxides. Ammonium sulfate, potassium persulfate, etc., 2-azo-bis-isobutyronitrile, 2-azo-bis-propionitrile, 2-azo-bis-cyclohexanedinitrile, etc. as diazo compounds, diazoaminobenzene, p -Nitrobenzenediazonium etc. can be mentioned.

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

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

In order to increase the refractive index of the layer, the light-scattering layer is oxidized with at least one metal selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony in addition to the light-transmitting fine particles. An inorganic filler having an average particle diameter of 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less may be contained.
Conversely, in order to increase the difference in refractive index from the translucent fine particles, the light scattering layer using the high refractive index translucent fine particles uses a silicon oxide to keep the refractive index of the layer low. You can also The preferred particle size is the same as that of the aforementioned inorganic filler. Since these inorganic fillers generally have a specific gravity higher than that of organic substances and can increase the density of the coating composition, they also have the effect of slowing the sedimentation rate of the light-transmitting fine particles.
The surface of the inorganic filler used in the light scattering layer is preferably subjected to a silane coupling treatment or a titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.
When using these inorganic fillers, the addition amount is preferably 10 to 90% of the total mass of the light scattering layer, more preferably 20 to 80%, and particularly preferably 30 to 75%.
Such an inorganic filler does not scatter because its particle size is sufficiently smaller than the wavelength of light, and a dispersion in which the filler is dispersed in a binder polymer behaves as an optically uniform substance.
An organosilane compound can be used for the light scattering layer. The addition amount of the organosilane compound is preferably 0.001 to 50% by mass, more preferably 0.01 to 20% by mass, and still more preferably 0.05 to 10% by mass, based on the total solid content of the containing layer (addition layer). 0.1 to 5% by mass is particularly preferable.

<Surfactant for light scattering layer>
The light scattering layer of the present invention is formed with a light diffusing layer in order to ensure surface uniformity such as coating unevenness, drying unevenness, point defects, etc. Contained in the coating composition. In particular, a fluorine-based surfactant is preferably used because an effect of improving surface defects such as coating unevenness, drying unevenness, and point defects of the antireflection film of the present invention appears in a smaller addition amount.
The purpose is to increase productivity by giving high-speed coating suitability while improving surface uniformity.

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

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

General formula

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

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

General formula

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

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

The preferred weight average molecular weight of the fluoropolymer used in the present invention is preferably 3000 to 100,000, more preferably 5,000 to 80,000.
Furthermore, the preferable addition amount of the fluoropolymer used in the present invention is in the range of 0.001 to 5% by mass, preferably in the range of 0.005 to 3% by mass, and more preferably, with respect to the coating solution. It is the range of 0.01-1 mass%. If the addition amount of the fluorine-based polymer is less than 0.001% by mass, the effect is insufficient, and if it exceeds 5% by mass, the coating film may not be sufficiently dried or the performance as a coating film (for example, reflectance) Adversely affect the scratch resistance).

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

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

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

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

General formula C

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

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

General formula D

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

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

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

In addition, the present inventors have confirmed that the intensity distribution of scattered light measured with a goniophotometer correlates with the viewing angle improvement effect. That is, the more the light emitted from the backlight is diffused by the light diffusion film installed on the polarizing plate surface on the viewing side, the better the viewing angle characteristics. However, if it is diffused too much, backscattering will increase and the front luminance will decrease, or the scattering will be too great and the image clarity will deteriorate. Therefore, it is necessary to control the scattered light intensity distribution within a certain range. Therefore, as a result of intensive studies, in order to achieve the desired visual characteristics, the scattered light intensity at 30 °, which correlates particularly with the visual angle improvement effect, is 0.01 relative to the light intensity at the outgoing angle 0 ° of the scattered light profile. % To 0.2% is preferable, and 0.02% to 0.15% is more preferable.
The scattered light profile can be measured for the created light scattering film using an automatic goniophotometer GP-5 manufactured by Murakami Color Research Laboratory.

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

Next, the low refractive index layer will be described below.
<Low refractive index layer>
The refractive index of the low refractive index layer in the antireflection film of the present invention is 1.30 to 1.55, preferably 1.35 to 1.45.
When the refractive index is less than 1.30, the antireflection performance is improved, but the mechanical strength of the film is lowered, and when it exceeds 1.55, the antireflection performance is remarkably deteriorated.
Further, the low refractive index layer preferably satisfies the following formula (I) from the viewpoint of reducing the reflectance.
Formula (I)
(M / 4) × 0.7 <n1 × d1 <(m / 4) × 1.3
In the formula, m is a positive odd number, n1 is the refractive index of the low refractive index layer, and d1 is the film thickness (nm) of the low refractive index layer. Further, λ is a wavelength, which is a value in the range of 500 to 550 nm.
In addition, satisfy | filling said numerical formula (I) means that m (positive odd number, usually 1) which satisfy | fills numerical formula (I) exists in the said wavelength range.

The material for forming the low refractive index layer will be described below.
The low refractive index layer is a cured film formed, for example, by applying, drying and curing a curable composition containing a fluorine-containing polymer as a main component.
<Fluoropolymer for low refractive index layer>
The fluoropolymer has a cured film with a coefficient of dynamic friction of 0.03 to 0.20, a contact angle with water of 90 to 120 °, and a sliding angle of pure water of 70 ° or less, and heat or ionization. A polymer that is cross-linked by radiation is preferable in terms of improving productivity in the case of coating and curing a roll film while transporting the web.
In addition, when the antireflection film of the present invention is mounted on an image display device, the lower the peel strength from a commercially available adhesive tape, the easier it is to peel off after sticking a seal or memo, so the peel strength is preferably 500 gf or less, 300 gf or less is more preferable, and 100 gf or less is most preferable. Further, the higher the surface hardness measured with a microhardness meter, the harder it is to scratch. Therefore, the surface hardness is preferably 0.3 GPa or more, and more preferably 0.5 GPa or more.

  The fluorine-containing polymer used for the low refractive index layer is a fluorine-containing polymer containing a fluorine atom in a range of 35 to 80% by mass and containing a crosslinkable or polymerizable functional group, for example, containing a perfluoroalkyl group In addition to hydrolysates and dehydration condensates of silane compounds [for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane], fluorinated monomer units and crosslinking reactive units are used as constituent units. A fluorine-containing copolymer is mentioned. In the case of a fluorinated copolymer, the main chain preferably consists of only carbon atoms. That is, it is preferable that the main chain skeleton does not have an oxygen atom or a nitrogen atom.

  Specific examples of the fluorine-containing monomer unit include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, perfluorooctylethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3- Dioxoles, etc.), (meth) acrylic acid partial or fully fluorinated alkyl ester derivatives (for example, Biscoat 6FM (manufactured by Osaka Organic Chemicals) and M-2020 (manufactured by Daikin)), fully or partially fluorinated vinyl ethers, etc. However, perfluoroolefins are preferable, and hexafluoropropylene is particularly preferable from the viewpoint of refractive index, solubility, transparency, availability, and the like.

  Examples of the crosslinking reactive unit include a structural unit obtained by polymerization of a monomer having a self-crosslinking functional group in the molecule such as glycidyl (meth) acrylate and glycidyl vinyl ether; carboxyl group, hydroxy group, amino group, sulfo group A structural unit obtained by polymerization of a monomer having, for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, maleic acid, crotonic acid, etc. And a structural unit in which a crosslinkable reactive group such as a (meth) acryloyl group is introduced by a polymer reaction (for example, it can be introduced by a technique such as allowing acrylic acid chloride to act on a hydroxy group).

  In addition to the fluorine-containing monomer unit and the cross-linking reactive unit, from the viewpoint of solubility in a solvent, film transparency, and the like, a monomer not containing a fluorine atom is appropriately copolymerized to introduce another polymerization unit. You can also There are no particular limitations on the monomer units that can be used in combination, such as olefins [ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.], acrylic esters [methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid 2 -Ethylhexyl], methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyl toluene, α-methylstyrene, etc.), vinyl ethers (methyl) Vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, etc.], vinyl esters [vinyl acetate, vinyl propionate, vinyl cinnamate, etc.], acrylamides [N-tertbutylacrylamide, N-silane] B hexyl acrylamide], methacrylamides, and acrylonitrile derivatives.

  As described in JP-A-10-25388 and JP-A-10-147739, a curing agent may be appropriately used in combination with the fluoropolymer.

The fluorine-containing polymer particularly useful in the present invention is a random copolymer of perfluoroolefin and vinyl ethers or vinyl esters. In particular, it preferably has a group capable of undergoing crosslinking reaction alone (radical reactive group such as (meth) acryloyl group, ring-opening polymerizable group such as epoxy group and oxetanyl group).
These crosslinkable group-containing polymerized units preferably occupy 5 to 70 mol%, particularly preferably 30 to 60 mol% of the total polymerized units of the polymer.

  A preferred form of the fluorine-containing polymer for the low refractive index layer used in the present invention is a copolymer represented by the general formula 1.

In General Formula 1, L represents a linking group having 1 to 10 carbon atoms, more preferably a linking group having 1 to 6 carbon atoms, particularly preferably a linking group having 2 to 4 carbon atoms, It may have a branched structure, may have a ring structure, or may have a heteroatom selected from O, N and S.
Preferred examples include * — (CH ₂ ) ₂ —O — **, * — (CH ₂ ) ₂ —NH — **, * — (CH ₂ ) ₄ —O — **, * — (CH ₂ ). _{6 -O - **, * - (} CH 2) 2 -O- (CH 2) 2 -O - **, * - CONH- (CH 2) 3 -O - **, * -CH 2 CH (OH ) CH ₂ —O — **, * —CH ₂ CH ₂ OCONH (CH ₂ ) ₃ —O — ** (* represents the connecting site on the polymer main chain side, and ** represents the connecting on the (meth) acryloyl group side) Represents a part). m represents 0 or 1;

  In general formula 1, X represents a hydrogen atom or a methyl group. From the viewpoint of curing reactivity, a hydrogen atom is more preferable.

  In the general formula 1, A represents a repeating unit derived from an arbitrary vinyl monomer, and is not particularly limited as long as it is a constituent component of a monomer copolymerizable with hexafluoropropylene. Tg (contributes to film hardness), solubility in solvents, transparency, slipperiness, dust / antifouling properties, etc., can be selected as appropriate, depending on the purpose, depending on the single or multiple vinyl monomers It may be configured.

  Preferred examples include methyl vinyl ether, ethyl vinyl ether, t-butyl vinyl ether, cyclohexyl vinyl ether, isopropyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, glycidyl vinyl ether, vinyl ethers such as allyl vinyl ether, vinyl acetate, vinyl propionate, butyric acid. (Meth) such as vinyl esters such as vinyl, methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, glycidyl methacrylate, allyl (meth) acrylate, (meth) acryloyloxypropyltrimethoxysilane Acrylates, styrene, styrene derivatives such as p-hydroxymethylstyrene, crotonic acid, maleic acid, itaconic acid Can be mentioned unsaturated carboxylic acids and derivatives thereof, more preferably ether derivatives, vinyl ester derivatives, particularly preferably a vinyl ether derivative.

x, y, and z represent the mol% of each constituent component, and preferably 30 ≦ x ≦ 60, 5 ≦ y ≦ 70, and 0 ≦ z ≦ 65, and more preferably 35 ≦ x ≦ 55 and 30 ≦ y ≦. 60, 0 ≦ z ≦ 20, particularly preferably 40 ≦ x ≦ 55, 40 ≦ y ≦ 55, and 0 ≦ z ≦ 10. However, x + y + z = 100.
A particularly preferred form of the copolymer used in the present invention is General Formula 2.

In General Formula 2, X represents the same meaning as in General Formula 1, and the preferred range is also the same.
n represents an integer of 2 ≦ n ≦ 10, preferably 2 ≦ n ≦ 6, and particularly preferably 2 ≦ n ≦ 4.
B represents a unit of a repeating unit derived from an arbitrary vinyl monomer, and may be composed of a single composition or a plurality of compositions. As an example, what was demonstrated as an example of A in the said General formula 1 is applicable.
x, y, z1 and z2 represent mol% of each repeating unit, and x and y preferably satisfy 30 ≦ x ≦ 60 and 5 ≦ y ≦ 70, respectively, more preferably 35 ≦ x ≦ 55. 30 ≦ y ≦ 60, particularly preferably 40 ≦ x ≦ 55 and 40 ≦ y ≦ 55. z1 and z2 preferably satisfy 0 ≦ z1 ≦ 65 and 0 ≦ z2 ≦ 65, more preferably 0 ≦ z1 ≦ 30 and 0 ≦ z2 ≦ 10, and 0 ≦ z1 ≦ 10, 0 It is particularly preferable that ≦ z2 ≦ 5. However, x + y + z1 + z2 = 100.
The copolymer represented by the general formula 1 or 2 is obtained, for example, by introducing a (meth) acryloyl group into a copolymer comprising a hexafluoropropylene component and a hydroxyalkyl vinyl ether component by any of the above-described methods. Can be synthesized. As the reprecipitation solvent used in this case, isopropanol, hexane, methanol and the like are preferable.
Preferable specific examples of the copolymer represented by the general formula 1 or 2 include those described in [0035] to [0047] of JP-A-2004-45462, and the method described in the publication Can be synthesized.

The curable composition preferably contains (A) the fluoropolymer, (B) inorganic fine particles, and (C) an organosilane compound described later.
<Inorganic fine particles for low refractive index layer>
The amount of the inorganic fine particles is preferably ^{1mg / m 2 ~100mg / m 2} , more preferably ^{5mg / m 2 ~80mg / m 2} , more preferably from ^{10mg / m 2 ~60mg / m 2} . If the amount is too small, the effect of improving the scratch resistance is reduced. It is preferable to be inside.
Since the inorganic fine particles are contained in the low refractive index layer, it is desirable that the inorganic fine particles have a low refractive index. Examples thereof include fine particles of magnesium fluoride and silica. In particular, silica fine particles are preferable in terms of refractive index, dispersion stability, and cost.
The average particle diameter of the inorganic fine particles is preferably 30% or more and 100% or less, more preferably 35% or more and 80% or less, and still more preferably 40% or more and 60% or less of the thickness of the low refractive index layer. That is, when the thickness of the low refractive index layer is 100 nm, the particle size of the silica fine particles is preferably 30 nm to 100 nm, more preferably 35 nm to 80 nm, and still more preferably 40 nm to 60 nm.
If the particle size of the inorganic fine particles is too small, the effect of improving the scratch resistance is reduced. Therefore, it is preferable to be within the above range. The inorganic fine particles may be either crystalline or amorphous, and may be monodispersed particles or aggregated particles as long as a predetermined particle size is satisfied. The shape is most preferably a spherical diameter, but there is no problem even if the shape is indefinite.
Here, the average particle diameter of the inorganic fine particles is measured by a Coulter counter.

In order to further reduce the increase in the refractive index of the low refractive index layer, the inorganic fine particles preferably have a hollow structure, and the refractive index of the inorganic fine particles is 1.17 to 1.40, more preferably 1. It is 17-1.35, More preferably, it is 1.17-1.30. Here, the refractive index represents the refractive index of the whole particle, and does not represent the refractive index of only the inorganic material of the outer shell in the case of hollow structure inorganic fine particles. At this time, when the radius of the cavity in the particle is a and the radius of the particle outer shell is b, the porosity x represented by the following formula (II) is (formula II)
^{x = (4πa 3/3)} / (4πb 3/3) × 100
Preferably it is 10 to 60%, More preferably, it is 20 to 60%, Most preferably, it is 30 to 60%.
If the refractive index of the hollow inorganic fine particles is made lower and the porosity is increased, the thickness of the outer shell becomes thinner and the strength of the particles becomes weaker. From the viewpoint of scratch resistance, the refractive index is 1 Particles with a low refractive index of less than .17 do not hold.
The refractive index of the inorganic fine particles was measured with an Abbe refractometer (manufactured by Atago Co., Ltd.).

In addition, at least one kind of inorganic fine particles (hereinafter referred to as “small size inorganic fine particles”) having an average particle size of less than 25% of the thickness of the low refractive index layer is referred to as “inorganic fine particles (hereinafter referred to as“ small size inorganic fine particles ”). It may be used in combination with “large-size inorganic fine particles”.
Since the small-sized inorganic fine particles can be present in the gaps between the large-sized inorganic fine particles, they can contribute as a retaining agent for the large-sized inorganic fine particles.
When the low refractive index layer is 100 nm, the average particle size of the small-sized inorganic fine particles is preferably 1 nm to 20 nm, more preferably 5 nm to 15 nm, and particularly preferably 10 nm to 15 nm. Use of such inorganic fine particles is preferable in terms of raw material costs and a retaining agent effect.
As described above, the inorganic fine particles have an average particle diameter of 30 to 100% of the thickness of the low refractive index layer as described above, have a hollow structure, and have a refractive index of 1.17 to 1. What is 40 is used especially preferably.

Inorganic fine particles are treated with physical surface treatment such as plasma discharge treatment or corona discharge treatment in order to stabilize dispersion in the dispersion or coating solution, or to improve the affinity and binding properties with the binder component. Further, chemical surface treatment with a surfactant, a coupling agent or the like may be performed. Of these, the use of a coupling agent is particularly preferred. As the coupling agent, an alkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. Of these, silane coupling treatment is particularly effective.
The coupling agent is used as a surface treatment agent for the inorganic fine particles of the low refractive index layer in advance for surface treatment prior to the preparation of the layer coating solution, and is further added as an additive during preparation of the layer coating solution. It is preferable to make it contain in a layer.
The inorganic fine particles are preferably dispersed in the medium in advance before the surface treatment in order to reduce the load of the surface treatment.

Next, (C) the organosilane compound will be described.
<Organosilane compound for low refractive index layer>
The curable composition contains a hydrolyzate of an organosilane compound and / or a partial condensate thereof (hereinafter, the obtained reaction solution is also referred to as a “sol component”). In particular, it is preferable in terms of achieving both the antireflection ability and the scratch resistance.
This sol component functions as a binder for the low refractive index layer by applying the curable composition and then condensing in a drying and heating process to form a cured product. Moreover, in this invention, since it has the said fluorine-containing polymer, the binder which has a three-dimensional structure is formed by irradiation of actinic light.
The organosilane compound is preferably represented by the following general formula [A].
Formula [A]
(R ¹⁰ ) _m -Si (X) _4-m

In the general formula [A], R ¹⁰ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, hexyl, decyl, hexadecyl and the like. The alkyl group is preferably an alkyl group having 1 to 30 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Examples of the aryl group include phenyl and naphthyl, and a phenyl group is preferable.
X represents a hydroxyl group or a hydrolyzable group, for example, an alkoxy group (preferably an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group or an ethoxy group), a halogen atom (for example, Cl, Br, I or the like). ), And R ² COO (R ² is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, such as CH ₃ COO, C ₂ H ₅ COO, etc.), preferably An alkoxy group, particularly preferably a methoxy group or an ethoxy group.
m represents an integer of 1 to 3, preferably 1 or 2, and particularly preferably 1.

When R ¹⁰ or X there are a plurality, a plurality of R ¹⁰ or X groups may be different, even the same, respectively.
The substituent contained in R ¹⁰ is not particularly limited, but a halogen atom (fluorine, chlorine, bromine, etc.), hydroxyl group, mercapto group, carboxyl group, epoxy group, alkyl group (methyl, ethyl, i-propyl, propyl, t-butyl etc.), aryl groups (phenyl, naphthyl etc.), aromatic heterocyclic groups (furyl, pyrazolyl, pyridyl etc.), alkoxy groups (methoxy, ethoxy, i-propoxy, hexyloxy etc.), aryloxy (phenoxy etc.) ), Alkylthio groups (methylthio, ethylthio, etc.), arylthio groups (phenylthio, etc.), alkenyl groups (vinyl, 1-propenyl, etc.), acyloxy groups (acetoxy, acryloyloxy, methacryloyloxy, etc.), alkoxycarbonyl groups (methoxycarbonyl, ethoxy) Carbonyl, etc.), aryloxy Carbonyl groups (phenoxycarbonyl, etc.), carbamoyl groups (carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-methyl-N-octylcarbamoyl, etc.), acylamino groups (acetylamino, benzoylamino, acrylicamino, methacrylamino) Etc.), and these substituents may be further substituted.

When there are a plurality of R ^{10 s} , at least one is preferably a substituted alkyl group or a substituted aryl group.
Among the organosilane compounds represented by the general formula [A], an organosilane compound having a vinyl polymerizable substituent represented by the following general formula [B] is preferable.

General formula [B]

In the general formula [B], R ¹ represents a hydrogen atom, a methyl group, a methoxy group, an alkoxycarbonyl group, a cyano group, a fluorine atom, or a chlorine atom. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group. A hydrogen atom, a methyl group, a methoxy group, a methoxycarbonyl group, a cyano group, a fluorine atom and a chlorine atom are preferred, a hydrogen atom, a methyl group, a methoxycarbonyl group, a fluorine atom and a chlorine atom are more preferred, and a hydrogen atom and a methyl group Is particularly preferred.
Y represents a single bond or * -COO-**, * -CONH-** or * -O-**, preferably a single bond, * -COO-** or * -CONH-**, * -COO-** is more preferable, and * -COO-** is particularly preferable. * Represents a position bonded to ═C (R ¹ ) —, and ** represents a position bonded to L.

  L represents a divalent linking chain. Specifically, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group having a linking group (for example, ether, ester, amide, etc.) inside, and a linking group inside. A substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, an alkylene group having a linking group therein is preferred, an unsubstituted alkylene group, an unsubstituted arylene group Further, an alkylene group having an ether or ester linking group inside is more preferable, an unsubstituted alkylene group, and an alkylene group having an ether or ester linking group inside is particularly preferable. Examples of the substituent include a halogen, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, and an aryl group, and these substituents may be further substituted.

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

  Two or more compounds of the general formula [A] and general formula [B] may be used in combination. Although the specific example of a compound represented by general formula [A] and general formula [B] is shown below, it is not limited.

  Of these, (M-1), (M-2), and (M-5) are particularly preferable.

  The hydrolyzate and / or partial condensate of the organosilane compound is generally produced by treating the organosilane compound in the presence of a catalyst. Catalysts include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid; organic acids such as oxalic acid, acetic acid, formic acid, methanesulfonic acid and toluenesulfonic acid; inorganic bases such as sodium hydroxide, potassium hydroxide and ammonia; triethylamine, Examples thereof include organic bases such as pyridine; metal alkoxides such as triisopropoxyaluminum and tetrabutoxyzirconium; metal chelate compounds having a metal such as Zr, Ti or Al as a central metal. In the present invention, it is preferable to use a metal chelate compound, an acid catalyst of inorganic acids and organic acids. Inorganic acids are preferably hydrochloric acid and sulfuric acid, and organic acids are preferably those having an acid dissociation constant (pKa value (25 ° C.)) of 4.5 or less in water, and further, acid dissociation constants in hydrochloric acid, sulfuric acid and water. Is preferably an organic acid having an acid dissociation constant of 2.5 or less in hydrochloric acid, sulfuric acid or water, more preferably an organic acid having an acid dissociation constant of 2.5 or less in water. Specifically, methanesulfonic acid, oxalic acid, phthalic acid, and malonic acid are more preferable, and oxalic acid is particularly preferable.

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

Specific examples of these metal chelate compounds include tri-n-butoxyethylacetoacetate zirconium, di-n-butoxybis (ethylacetoacetate) zirconium, n-butoxytris (ethylacetoacetate) zirconium, tetrakis (n-propylacetate). Zirconium chelate compounds such as acetate) zirconium, tetrakis (acetylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium; diisopropoxy bis (ethylacetoacetate) titanium, diisopropoxy bis (acetylacetate) titanium, diiso Titanium chelate compounds such as propoxy bis (acetylacetone) titanium; diisopropoxyethyl acetoacetate aluminum, diisopropyl Poxyacetylacetonate aluminum, isopropoxybis (ethylacetoacetate) aluminum, isopropoxybis (acetylacetonate) aluminum, tris (ethylacetoacetate) aluminum, tris (acetylacetonate) aluminum, monoacetylacetonate bis (ethyl) An aluminum chelate compound such as acetoacetate) aluminum.
Among these metal chelate compounds, tri-n-butoxyethyl acetoacetate zirconium, diisopropoxybis (acetylacetonate) titanium, diisopropoxyethyl acetoacetate aluminum, and tris (ethyl acetoacetate) aluminum are preferable. These metal chelate compounds can be used individually by 1 type or in mixture of 2 or more types. Moreover, the partial hydrolyzate of these metal chelate compounds can also be used.

  In the present invention, it is preferable that a β-diketone compound and / or a β-ketoester compound is further added to the curable composition. This will be further described below.

The β-diketone compound and / or β-ketoester compound represented by the general formula R ⁴ COCH ₂ COR ⁵ is used in the present invention, and is used as a stability improver for the curable composition used in the present invention. It works. Here, R ⁴ represents an alkyl group having 1 to 10 carbon atoms, and R ⁵ represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms. That is, by coordinating with a metal atom in the metal chelate compound (zirconium, titanium and / or aluminum compound), the condensation reaction of the hydrolyzate and / or partial condensate of the organosilane compound by these metal chelate compounds is performed. It is considered that the promoting action is suppressed and the storage stability of the resulting composition is improved. R ⁴ and R ⁵ constituting the β- diketone compound and / or β- ketoester compound are the same as R ⁴ and R ⁵ constituting the metal chelate compound.

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

The compounding amount of the organosilane compound is preferably 0.1 to 50% by mass, more preferably 0.5 to 20% by mass, and most preferably 1 to 10% by mass based on the total solid content of the low refractive index layer.
The organosilane compound may be added directly to the curable composition (coating liquid for light scattering layer, low refractive index layer, etc.), but the organosilane compound is treated in the presence of a catalyst in advance. It is preferable to prepare a hydrolyzate and / or partial condensate of a silane compound and prepare the curable composition using the obtained reaction solution (sol solution). In the present invention, first, the organosilane compound A composition containing a hydrolyzate and / or a partial condensate and a metal chelate compound is prepared, and a liquid obtained by adding a β-diketone compound and / or a β-ketoester compound thereto is added to at least a light scattering layer or a low refractive index layer. It is preferable to coat it in a single layer coating solution.

  5-100 mass% is preferable, the usage-amount of the sol component of the organosilane with respect to a fluorine-containing polymer in a low refractive index layer has more preferable 5-40 mass%, 8-35 mass% is still more preferable, 10-30 mass % Is particularly preferred. If the amount used is small, it is difficult to obtain the effect of the present invention, and if the amount used is too large, the refractive index increases or the shape / surface shape of the film deteriorates.

  An inorganic filler other than the above-described inorganic fine particles can be added to the curable composition in an addition amount within a range that does not impair the desired effect of the present invention. Details of the inorganic filler will be described later.

(Sol-gel material)
Various sol-gel materials can also be used as the material for the low refractive index layer. As such a sol-gel material, metal alcoholates (alcohols such as silane, titanium, aluminum, and zirconium), organoalkoxy metal compounds, and hydrolysates thereof can be used. In particular, alkoxysilane, organoalkoxysilane and its hydrolyzate are preferable. Examples of these include tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, etc.), alkyltrialkoxysilane (methyltrimethoxysilane, ethyltrimethoxysilane, etc.), aryltrialkoxysilane (phenyltrimethoxysilane, etc.), dialkyl. Examples thereof include dialkoxysilane and diaryl dialkoxysilane. In addition, organoalkoxysilanes having various functional groups (vinyl trialkoxysilane, methylvinyl dialkoxysilane, γ-glycidyloxypropyltrialkoxysilane, γ-glycidyloxypropylmethyl dialkoxysilane, β- (3,4-epoxy) Dicyclohexyl) ethyltrialkoxysilane, γ-methacryloyloxypropyltrialkoxysilane, γ-aminopropyltrialkoxysilane, γ-mercaptopropyltrialkoxysilane, γ-chloropropyltrialkoxysilane, etc.), perfluoroalkyl group-containing silane compounds ( For example, it is also preferable to use (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, etc.). In particular, the use of a fluorine-containing silane compound is preferable in terms of lowering the refractive index of the layer and imparting water and oil repellency.

[Other substances contained in curable composition for low refractive index layer]
The curable composition is prepared by adding various additives, a radical polymerization initiator, and a cationic polymerization initiator to the (A) fluorine-containing polymer, (B) inorganic fine particles, and (C) the organosilane compound as necessary. Further, they are prepared by dissolving them in a suitable solvent. At this time, the concentration of the solid content is appropriately selected according to the use, but is generally about 0.01 to 60% by mass, preferably 0.5 to 50% by mass, particularly preferably 1% to 20% by mass. %.

  Curing agents such as polyfunctional (meth) acrylate compounds, polyfunctional epoxy compounds, polyisocyanate compounds, aminoplasts, polybasic acids or anhydrides thereof from the viewpoint of interfacial adhesion with the lower layer directly in contact with the low refractive index layer Can also be added in small amounts. When adding these, it is preferable to set it as the range of 30 mass% or less with respect to the total solid of a low-refractive-index layer film, It is more preferable to set it as the range of 20 mass% or less, The range of 10 mass% or less It is particularly preferable that

  In addition, for the purpose of imparting properties such as antifouling properties, water resistance, chemical resistance, and slipping properties, a known silicone compound or fluorine compound antifouling agent, slipping agent, and the like may be appropriately added. When these additives are added, it is preferably added in the range of 0.01 to 20% by mass of the total solid content of the low refractive index layer, more preferably in the range of 0.05 to 10% by mass. Particularly preferred is 0.1 to 5% by mass.

  Preferable examples of the silicone compound include those having a substituent at the terminal and / or side chain of a compound chain containing a plurality of dimethylsilyloxy units as repeating units. The compound chain containing dimethylsilyloxy as a repeating unit may contain a structural unit other than dimethylsilyloxy. The substituents may be the same or different, and a plurality of substituents are preferable. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, fluoroalkyl group, polyoxyalkylene group, carboxyl group, amino group and the like. It is done. Although there is no restriction | limiting in particular in molecular weight, It is preferable that it is 100,000 or less, It is especially preferable that it is 50,000 or less, It is most preferable that it is 3000-30000. Although there is no restriction | limiting in particular in silicone atom content of a silicone type compound, it is preferable that it is 18.0 mass% or more, it is especially preferable that it is 25.0-37.8 mass%, and 30.0-37.0. Most preferably, it is mass%. Examples of preferred silicone compounds are X-22-174DX, X-22-2426, X-22-164B, X22-164C, X-22-170DX, X-22-176D, X, manufactured by Shin-Etsu Chemical Co., Ltd. -22-1821 (named above), Chisso Corporation, FM-0725, FM-7725, FM-4421, FM-5521, FM6621, FM-1121, Gelest DMS-U22, RMS-033, RMS- 083, UMS-182, DMS-H21, DMS-H31, HMS-301, FMS121, FMS123, FMS131, FMS141, FMS221 (named above) but not limited thereto.

As the fluorine compound, a compound having a fluoroalkyl group is preferable. The fluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and a straight chain (for example, —CF ₂ CF ₃ , —CH ₂ (CF ₂ ) ₄ H, —CH ₂ (CF ₂ ) ₈ CF ₃ , —CH ₂ CH ₂ (CF ₂ ) ₄ H, etc.), even branched structures (eg, —CH (CF ₃ ) ₂ , —CH ₂ CF (CF ₃ ) ₂ , —CH (CH ₃ ) CF ₂ CF ₃ , —CH (CH ₃ ) (CF ₂ ) ₅ CF ₂ H, etc.), but alicyclic structures (preferably 5-membered or 6-membered rings such as perfluorocyclohexyl groups) , A perfluorocyclopentyl group or an alkyl group substituted with these, and may have an ether bond (for example, —CH ₂ OCH ₂ CF ₂ CF ₃ , —CH ₂ CH ₂ OCH ₂ C). ₄ F ₈ H, —CH ₂ CH ₂ OCH ₂ CH ₂ C ₈ F ₁₇ , —CH ₂ C H ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ H, etc.). A plurality of the fluoroalkyl groups may be contained in the same molecule.
It is preferable that the fluorine-based compound further has a substituent that contributes to bond formation or compatibility with the low refractive index layer film. The substituents may be the same or different, and a plurality of substituents are preferable. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, polyoxyalkylene group, carboxyl group, amino group and the like. The fluorine-based compound may be a polymer or an oligomer with a compound not containing a fluorine atom, and the molecular weight is not particularly limited. Although there is no restriction | limiting in particular in fluorine atom content of a fluorine-type compound, It is preferable that it is 20 mass% or more, It is especially preferable that it is 30-70 mass%, It is most preferable that it is 40-70 mass%. Examples of preferred fluorine-based compounds include Daikin Chemical Industries, R-2020, M-2020, R-3833, M-3833 (named above), Dainippon Ink, Megafac F-171. , F-172, F-179A, defender MCF-300 (trade name), etc., but are not limited thereto.

  For the purpose of imparting properties such as dust resistance and antistatic properties, a known cationic surfactant or a dustproof agent such as a polyoxyalkylene compound, an antistatic agent, or the like can be appropriately added. These dustproofing agent and antistatic agent may contain the structural unit as a part of the function in the above-mentioned silicone compound or fluorine compound. When these are added as additives, it is preferably added in the range of 0.01 to 20% by mass, more preferably in the range of 0.05 to 10% by mass of the total solid content of the low n layer. Particularly preferably 0.1 to 5% by mass. Examples of preferred compounds include, but are not limited to, Dainippon Ink Co., Ltd., Megafac F-150 (trade name), Toray Dow Corning Co., Ltd., SH-3748 (trade name), and the like. Do not mean.

<Transparent support>
A plastic film is preferably used as the transparent support of the light scattering film or antireflection film of the present invention. As the polymer forming the plastic film, cellulose acylate (eg, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, typically TAC-TD80U, TD80UL, etc. manufactured by Fuji Photo Film), Polyamide, polycarbonate, polyester (eg, polyethylene terephthalate, polyethylene naphthalate), polystyrene, polyolefin, norbornene resin (Arton: trade name, manufactured by JSR), amorphous polyolefin (ZEONEX: trade name, manufactured by ZEON Corporation), Etc. Among these, triacetyl cellulose, polyethylene terephthalate, norbornene resin, and amorphous polyolefin are preferable, and triacetyl cellulose is particularly preferable.
Cellulose acylate consists of a single layer or a plurality of layers. A single-layer cellulose acylate is prepared by drum casting or band casting disclosed in Japanese Patent Application Laid-Open No. 7-11055, and the latter cellulose acylate is a feature of the published patent publication. It is prepared by the so-called co-casting method disclosed in Japanese Utility Model Publication Nos. 61-94725 and 62-43846. That is, the raw material flakes are solvents such as halogenated hydrocarbons (dichloromethane, alcohols (methanol, ethanol, butanol, etc.), esters (methyl formate, methyl acetate, etc.), ethers (dioxane, dioxolane, diethyl ether, etc.), etc. A solution (called a dope) with various additives such as a plasticizer, an ultraviolet absorber, an anti-degradation agent, a slipping agent, and a peeling accelerator is added to the horizontal endless as necessary. When casting by a dope supply means (called a die) on a support composed of a metal belt or a rotating drum, a single dope is cast in a single layer if it is a single layer, and a high concentration in the case of multiple layers. A low-concentration dope is co-cast on both sides of the cellulose ester dope, and the film is dried to some extent on the support to release the rigid film, and then peeled off from the support. A process comprising passed through a drying section by species of the conveying means to remove the solvent.

  A typical solvent for dissolving cellulose acylate as described above is dichloromethane. However, from the viewpoint of the global environment and working environment, the solvent preferably does not substantially contain a halogenated hydrocarbon such as dichloromethane. “Substantially free” means that the proportion of halogenated hydrocarbon in the organic solvent is less than 5% by mass (preferably less than 2% by mass).

  Various cellulose acylate films as described above (films made of triacetyl cellulose and the like) and production methods thereof are described in JIII Journal of Technical Disclosure No. 2001-1745 (issued on March 15, 2001). Yes.

The thickness of the cellulose acylate film is preferably 40 μm to 120 μm. In consideration of handling suitability, coating suitability, etc., about 80 μm is preferable. However, due to the recent trend of thinning display devices, there is a great need for thinning of the polarizing plate. When such a thin cellulose acylate film is used as a transparent support for the light scattering film or antireflection film of the present invention, the solvent, film thickness, crosslinking shrinkage ratio, etc. of the layer directly applied to the cellulose acylate film It is preferable to avoid problems such as handling and application suitability by optimizing the above.
<About other layers>
As another layer that may be provided between the transparent support and the light scattering layer of the present invention, an antistatic layer (when there is a request to reduce the surface resistance value from the display side, there is a problem of dust on the surface, etc. And a hard coat layer (when the light scattering layer alone is insufficient in hardness), a moisture-proof layer, an adhesion improving layer, a rainbow unevenness (interference unevenness) preventing layer, and the like.
These layers can be formed by a known method.

Although the light-scattering film of this invention can be formed with the following method, it is not restrict | limited to this method.
[Adjustment of coating solution]

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

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

[Application]
Next, a coating solution for forming a light scattering layer and, if necessary, a low refractive index layer is applied on the surface of a continuously running web by an extrusion method (die coating method), and then coated on a transparent support. Heat and dry. Thereafter, the monomer for forming the light scattering layer or the low refractive index layer is polymerized and cured by light irradiation and / or heating. Thereby, a light scattering layer and a low refractive index layer are formed. Note that the light scattering layer may be formed of one layer or a plurality of layers, for example, two to four layers. Moreover, although you may provide directly on a transparent support body, you may provide through other layers, such as an antistatic layer and a moisture-proof layer.

In general, the extrusion method (die coating method) is preferably used from the viewpoint of a high production rate. In particular, a die coater that can be preferably used in a region with a small amount of wet coating (20 cc / m ² or less) such as the light scattering layer or the antireflection layer of the present invention will be described below.
<Die coater configuration>

  FIG. 2 is a sectional view of a coater using a slot die embodying the present invention. The coater 10 is applied to the web W supported by the backup roll 11 and continuously applied from the slot die 13 as a bead 14a to form a coating film 14b on the web W.

  Inside the slot die 13, a pocket 15 and a slot 16 are formed. The cross section of the pocket 15 is configured by a curve and a straight line. For example, the pocket 15 may be substantially circular as shown in FIG. 2 or may be semicircular. The pocket 15 is a liquid storage space for the coating liquid extended in the width direction of the slot die 13 with its cross-sectional shape, and the length of the effective extension is generally equal to or slightly longer than the coating width. The supply of the coating liquid 14 to the pocket 15 is performed from the side surface of the slot die 13 or from the center of the surface opposite to the slot opening 16a. The pocket 15 is provided with a stopper that prevents the coating liquid 14 from leaking out.

  The slot 16 is a flow path of the coating liquid 14 from the pocket 15 to the web W, and has a cross-sectional shape in the width direction of the slot die 13 similarly to the pocket 15, and the opening 16a located on the web side is generally Using a width regulating plate (not shown), the width is adjusted to be approximately the same as the coating width. The angle between the slot tip of the slot 16 and the tangent in the web running direction of the backup roll 11 is preferably 30 ° or more and 90 ° or less.

  The tip lip 17 of the slot die 13 where the opening 16a of the slot 16 is located is tapered, and the tip is a flat part 18 called a land. In the land 18, the upstream side in the traveling direction of the web W with respect to the slot 16 is referred to as an upstream lip land 18 a and the downstream side is referred to as a downstream lip land 18 b.

FIG. 3 shows a cross-sectional shape of the slot die 13 in comparison with a conventional one, (A) shows the slot die 13 of the present invention, and (B) shows a conventional slot die 30. In the conventional slot die 30, the distance between the upstream lip land 31a and the web of the downstream lip land 31b is equal. Reference numeral 32 denotes a pocket, and 33 denotes a slot. On the other hand, in the slot die 13 of the present invention, the downstream side lip land length I _LO is shortened, whereby the wet film thickness of 20 μm or less can be applied with high accuracy. Even when the wet film thickness is 20 μm or more, the coated surface can be made more favorable.

The land length I _UP of the upstream lip land 18a is not particularly limited, but is preferably used in the range of 500 μm to 1 mm. The land length I _LO of the downstream lip land 18b is not less than 30 μm and not more than 100 μm, preferably not less than 30 μm and not more than 80 μm, more preferably not less than 30 μm and not more than 60 μm. If the land length I _LO of the downstream lip is shorter than 30 μm, the edge or land of the tip lip is likely to be chipped, streaks are likely to occur in the coating film, and consequently application is impossible. In addition, it becomes difficult to set the position of the wetting line on the downstream side, and there is a problem that the coating liquid tends to spread on the downstream side. It has been conventionally known that this spreading of the coating liquid on the downstream side means non-uniform wetting lines and leads to a problem of causing a defective shape such as a streak on the coating surface. On the other hand, when the land length I _LO of the downstream lip is longer than 100 μm, the bead itself cannot be formed, so that it is impossible to apply the thin layer.

Further, the downstream lip land 18b has an overbite shape closer to the web W than the upstream lip land 18a. Therefore, the degree of decompression can be lowered, and a bead suitable for thin film coating can be formed. The difference in distance between the downstream side lip land 18b and the web W of the upstream side lip land 18a (hereinafter referred to as overbit length LO) is preferably 30 μm or more and 120 μm or less, more preferably 30 μm or more and 100 μm or less, and most preferably 30 μm. It is 80 μm or less. When the slot die 13 has an overbite shape, the gap _GL between the tip lip 17 and the web W indicates the gap between the downstream lip land 18b and the web W.

FIG. 4 is a perspective view showing the slot die and its periphery in the coating process in which the present invention is implemented. On the opposite side of the web W in the direction of travel, the decompression chamber 40 is installed at a position where it does not come into contact with the bead 14a so that sufficient decompression adjustment can be performed. The decompression chamber 40 is provided with a back plate 40a and a side plate 40b for maintaining its operating efficiency, and there are gaps G _B , G between the back plate 40a and the web W and between the side plate 40b and the web W, respectively. _S exists. 5 and 6 are cross-sectional views showing the decompression chamber 40 and the web W that are close to each other. The side plate and the back plate may be integrated with the chamber main body as shown in FIG. 5, or may have a structure fastened to the chamber with screws 40c or the like so that the gap can be appropriately changed as shown in FIG. In any structure, portions that are actually opened between the back plate 40a and the web W and between the side plate 40b and the web W are defined as gaps G _B and G _S , respectively. The gap G _B between the back plate 40a and the web W of the decompression chamber 40, when the vacuum chamber 40 is placed under the web W and the slot die 13 as shown in FIG. 4, from the uppermost end of the back plate 40a to the web W Indicates the gap.

Is preferably placed in the gap G _B between the back plate 40a and the web W is larger than the gap G _L between the end lip 17 and the web W of the slot die 13, beads vicinity due to the eccentricity of the backup roll 11 thereby The change in the degree of decompression can be suppressed. For example, when the gap G _L between the end lip 17 and the web W of the slot die 13 is 30μm or more 100μm or less, the gap G _B between the back plate 40a and the web W is preferably 100μm or 500μm or less.

<Material and accuracy>
The longer the length of the tip lip on the traveling direction side of the web in the web traveling direction, the more disadvantageous it is for bead formation.If this length varies between arbitrary locations in the slot die width direction, It becomes unstable. Therefore, it is preferable that the fluctuation width in the slot die width direction is within 20 μm.
Further, regarding the material of the tip lip of the slot die, if a material such as stainless steel is used, the length of the slot die tip lip in the web running direction is set to 30 to 100 μm as described above. Even within this range, the accuracy of the tip lip cannot be satisfied. Therefore, in order to maintain high processing accuracy, it is important to use a cemented carbide material as described in Japanese Patent No. 2817053. Specifically, at least the tip lip of the slot die is preferably made of a cemented carbide formed by bonding carbide crystals having an average particle size of 5 μm or less. Cemented carbides include carbide carbide particles such as tungsten carbide (hereinafter referred to as WC) bonded by a bonding metal such as cobalt, and other bonding metals include titanium, tantalum, niobium, and mixed metals thereof. Can also be used. The average particle size of the WC crystal is more preferably 3 μm or less.
In order to realize high-precision coating, the length of the land on the web traveling direction side of the tip lip and the variation in the slot die width direction of the gap with the web are also important factors. It is desirable to achieve a combination of these two factors, that is, straightness within a range in which the fluctuation range of the gap can be suppressed to some extent. Preferably, the straightness of the tip lip and the backup roll is set so that the fluctuation width of the gap in the slot die width direction is 5 μm or less.

<Application speed>
By achieving the accuracy of the backup roll and the tip lip as described above, the coating method preferably used in the present invention has high film thickness stability during high-speed coating. Furthermore, since the coating method of the present invention is a pre-measuring method, it is easy to ensure a stable film thickness even during high-speed coating. The coating method of the present invention can be applied at high speed and with good film thickness stability to a coating solution having a low coating amount such as the antireflection film of the present invention. Although coating is possible with other coating methods, the dip coating method inevitably causes vibration of the coating liquid in the liquid receiving tank, and stepped unevenness is likely to occur. In the reverse roll coating method, stepped unevenness is likely to occur due to eccentricity or deflection of the roll related to coating. In addition, since these coating methods are post-measuring methods, it is difficult to ensure a stable film thickness. From the viewpoint of productivity, it is preferable to apply at a rate of 25 m / min or more by using the production method of the present invention.

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

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

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

[Curing]
After the solvent drying zone, the coating is cured by passing through a zone where the coating is cured by ionizing radiation and / or heat on the web. For example, if the coating film is UV curable, it is to cure each layer by irradiating an irradiation amount of ultraviolet rays of 10mJ / cm ² ~1000mJ / cm ² by an ultraviolet lamp preferred. At that time, the irradiation distribution in the width direction of the web is preferably 50 to 100%, more preferably 80 to 100%, including both ends with respect to the central maximum irradiation. Further, when it is necessary to purge nitrogen gas or the like to lower the oxygen concentration in order to promote surface hardening, the oxygen concentration is preferably 0.01% to 5%, and the distribution in the width direction is 2% or less in terms of oxygen concentration. Is preferred.

  In addition, when the curing rate (100-residual functional group content) of the light scattering layer becomes a certain value less than 100%, the low refractive index layer of the present invention is provided on the light scattering layer to reduce the light scattering layer by ionizing radiation and / or heat. When the refractive index layer is cured, if the curing rate of the lower light scattering layer is higher than before the low refractive index layer is provided, the adhesion between the light scattering layer and the low refractive index layer is improved, which is preferable.

The light-scattering film and antireflection film of the present invention produced as described above can be used for a liquid crystal display device by forming a polarizing plate using the film. In this case, it arrange | positions on the outermost surface of a display by providing an adhesive layer on one side. The antireflection film of the present invention is preferably used for at least one of the two protective films sandwiching the polarizing film in the polarizing plate from both sides.
Since the antireflection film of the present invention also serves as a protective film, the production cost of the polarizing plate can be reduced. Further, by using the antireflection film of the present invention as the outermost layer, reflection of external light and the like can be prevented, and a polarizing plate having excellent scratch resistance, antifouling property and the like can be obtained.

  When creating a polarizing plate using the light-scattering film or antireflection film of the present invention as one of the surface protective films of two polarizing films, the antireflection film is provided on the side having an antireflection structure. It is preferable to improve the adhesion on the adhesive surface by hydrophilizing the surface of the transparent support opposite to the surface, that is, the surface to be bonded to the polarizing film.

[Saponification]
(1) Method of immersing in an alkali solution A method of saponifying all surfaces having reactivity with alkali on the entire surface of the film by immersing a light-scattering film or an antireflection film in an alkali solution under appropriate conditions. There is no need for special equipment, which is preferable from the viewpoint of cost. The alkaline liquid is preferably a sodium hydroxide aqueous solution. A preferred concentration is 0.5 to 3 mol / L, particularly preferably 1 to 2 mol / L. The liquid temperature of a preferable alkali liquid is 30-75 degreeC, Most preferably, it is 40-60 degreeC.
The combination of the saponification conditions is preferably a combination of relatively mild conditions, but can be set according to the material and configuration of the light scattering film and the antireflection film, and the target contact angle.
After being immersed in the alkaline solution, it is preferable to sufficiently wash with water or neutralize the alkaline component by immersing in a dilute acid so that the alkaline component does not remain in the film.

By saponification treatment, the surface of the transparent support opposite to the surface having the light scattering layer or antireflection layer is hydrophilized. The protective film for polarizing plate is used by adhering the hydrophilic surface of the transparent support to the polarizing film.
The hydrophilized surface is effective for improving the adhesiveness with the adhesive layer mainly composed of polyvinyl alcohol.
In the saponification treatment, the lower the contact angle with respect to the surface of the transparent support on the side opposite to the side having the light scattering layer or the low refractive index layer, the better from the viewpoint of adhesion to the polarizing film. At the same time, since it is damaged by alkali from the surface having the light scattering layer and the low refractive index layer to the inside, it is important to set the necessary minimum reaction conditions. When the contact angle to water of the transparent support on the opposite surface is used as an index of damage to each layer due to alkali, particularly when the transparent support is triacetylcellulose, preferably 10 to 50 degrees, more preferably Is 30 to 50 degrees, more preferably 40 to 50 degrees. If it is 50 degrees or more, there is a problem in the adhesion to the polarizing film, which is not preferable. On the other hand, if it is less than 10 degrees, the damage received by the antireflection film is too large, and physical strength is impaired, which is not preferable.

(2) Method of applying alkaline solution As a means for avoiding damage to each film in the above-mentioned immersion method, the alkaline solution is applied only to the surface opposite to the surface having the light scattering layer or antireflection film under appropriate conditions. An alkaline solution coating method of heating, washing with water and drying is preferably used. The application in this case means that an alkaline solution or the like is brought into contact only with the surface to be saponified, and in addition to the application, spraying, contact with a belt containing the solution, or the like may be performed. Including. By adopting these methods, a separate facility and process for applying an alkaline solution are required, which is inferior to the immersion method (1) from the viewpoint of cost. On the other hand, since the alkali solution contacts only the surface to be saponified, the opposite surface can have a layer using a material that is weak against the alkali solution. For example, vapor deposition films and sol-gel films have various effects such as corrosion, dissolution, and peeling due to alkali solution, so it is not desirable to use the immersion method. Is possible.

  In any of the saponification methods (1) and (2), it can be carried out after each layer is formed by unwinding from a roll-shaped support, so that it is added after the light scattering film or antireflection film manufacturing step. It may be performed by a series of operations. Furthermore, the polarizing plate can be produced more efficiently than the same operation with a single wafer by continuously performing the pasting step with the polarizing plate made of the unwound support.

(3) Method of protecting and saponifying a light scattering layer and an antireflection layer with a laminate film When the light scattering layer and / or the low refractive index layer is insufficient in resistance to an alkaline solution as in the above (2) Then, after forming the final layer, the laminate film is bonded to the surface on which the final layer is formed and then immersed in an alkaline solution to hydrophilize only the surface of the triacetyl cellulose opposite to the surface on which the final layer is formed. After being laminated, the laminate film can be peeled off. Even in this method, only the surface opposite to the surface on which the final layer of the triacetyl cellulose film is formed is subjected to the hydrophilization treatment necessary for the polarizing plate protective film without damaging the light scattering layer and the low refractive index layer. Can do. Compared with the method (2), the laminate film is generated as waste, but there is an advantage that a device for applying a special alkaline solution is unnecessary.

(4) Method of immersing in an alkali solution after forming up to the light scattering layer Although the light scattering layer is resistant to the alkaline solution, if the low refractive index layer is insufficiently resistant to the alkaline solution, after forming up to the light scattering layer It is also possible to soak both surfaces in an alkaline solution to hydrophilize both sides, and then form a low refractive index layer on the light scattering layer. Although the manufacturing process is complicated, there is an advantage that the interlayer adhesion between the light scattering layer and the low refractive index layer is improved particularly when the low refractive index layer has a hydrophilic group such as a fluorine-containing sol-gel film.

(5) Method of forming a light scattering layer or an antireflection layer on a previously saponified triacetyl cellulose film The saponification of the triacetyl cellulose film by immersing it in an alkaline solution in advance, either directly or on the other side You may form a light-scattering layer and a low-refractive-index layer through a layer. In the case of saponification by dipping in an alkali solution, interlayer adhesion between the light scattering layer or other layers and the triacetyl cellulose surface hydrophilized by saponification may deteriorate. In such a case, after the saponification, only the surface on which the light scattering layer or other layer is formed is treated with corona discharge, glow discharge or the like to remove the hydrophilic surface, and then the light scattering layer or other layer. Can be dealt with by forming Further, when the light scattering layer or other layer has a hydrophilic group, the interlayer adhesion may be good.

Below, the polarizing plate using the light-scattering film or antireflection film of this invention and the liquid crystal display device using this polarizing plate are demonstrated.
[Polarizer]
The preferable polarizing plate of this invention has the light-scattering film or antireflection film of this invention as at least one of the protective film (polarizing plate protective film) of a polarizing film. As described above, the protective film for polarizing plate has a contact angle with water of 10 ° on the surface of the transparent support opposite to the side having the light scattering layer and the antireflection layer, that is, the surface to be bonded to the polarizing film. It is preferably in the range of ˜50 degrees.
By using the light scattering film or antireflection film of the present invention as a protective film for a polarizing plate, a light scattering function with excellent physical strength and light resistance, or a polarizing plate having an antireflection function can be produced, resulting in significant cost reduction. Therefore, the display device can be thinned.
In addition, a polarizing plate using the light-scattering film or antireflection film of the present invention as one of the protective films for a polarizing plate and an optical compensation film having optical anisotropy described later as the other protective film of the polarizing film is prepared. By doing so, the visibility and contrast in the bright room of a liquid crystal display device can be improved, and the polarizing plate which can expand the viewing angle of the upper and lower, right and left very much can be produced.

[Optical compensation layer]
By providing the polarizing plate with an optical compensation layer (retardation layer), the viewing angle characteristics of the liquid crystal display screen can be improved.
As the optical compensation layer, a known layer can be used. However, in terms of widening the viewing angle, the optical compensation layer has a layer having optical anisotropy made of a compound having a discotic structural unit, and is transparent to the discotic compound. An optical compensation layer characterized in that the angle formed with the support varies with the distance from the transparent support.
The angle preferably increases as the distance from the transparent support surface side of the optically anisotropic layer made of the discotic compound increases.
When the optical compensation layer is used as a protective film for a polarizing film, the surface on the side to be bonded to the polarizing film is preferably saponified, and is preferably performed according to the saponifying process.

[Polarizing film]
As the polarizing film, a known polarizing film or a polarizing film cut out from a long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction may be used. A long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction is produced by the following method.
That is, a polarizing film stretched by applying tension while holding both ends of a continuously supplied polymer film by a holding means, stretched at least 1.1 to 20.0 times in the film width direction, The progress of the film is such that the difference between the moving speeds in the longitudinal direction of the holding device is within 3%, and the angle formed by the film moving direction at the exit of the step of holding both ends of the film and the substantial stretching direction of the film is inclined by 20 to 70 °. The film can be produced by a stretching method in which the direction is bent while holding both ends of the film. In particular, those inclined by 45 ° are preferably used from the viewpoint of productivity.

  The method for stretching the polymer film is described in detail in paragraphs 0020 to 0030 of JP-A-2002-86554.

<Image display device>
The light-scattering film and antireflection film produced by the production method of the present invention are liquid crystal display devices (LCD), plasma display panels (PDP), electroluminescence displays (ELD), cathode ray tube display devices (CRT), field emission displays. (FED) and surface electric field display (SED) can be applied to an image display device, but it is particularly preferably applicable to a liquid crystal display device (LCD).

<Liquid crystal display device>
When the light-scattering film and the antireflection film produced by the production method of the present invention are used as one side of the surface protective film of the polarizing film, twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA) ), In-plane switching (IPS), optically compensated bend cell (OCB), and other modes of transmissive, reflective, or transflective liquid crystal display devices.

  The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). 176625 (in Japanese Patent Publication No. 176625), and (2) a liquid crystal cell (SID97, Digest of tech. Papers (Proceedings) 28 (1997) 845 in which the VA mode is converted into a multi-domain (for MVA mode) in order to enlarge the viewing angle. ), (3) A liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Preliminary collections 58-59 of the Japan Liquid Crystal Society) (1998)) and (4) SURVAVAL mode liquid crystal cells (announced at LCD International 98).

  The OCB mode liquid crystal cell is a liquid crystal display device using a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between the upper part and the lower part of the liquid crystal cell. It is disclosed in the specifications of Japanese Patent Nos. 45882525 and 5410422. Since the rod-like liquid crystal molecules are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. For this reason, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.

  In an ECB mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and is most frequently used as a color TFT liquid crystal display device, and is described in many documents. For example, it is described in “EL, PDP, LCD display” published by Toray Research Center (2001).

  In particular, for TN mode and IPS mode liquid crystal display devices, as described in JP-A-2001-100043, an optical compensation film having a viewing angle widening effect is included in the two protective films on the back and front of the polarizing film. By using it on the surface opposite to the antireflection film of the present invention, a polarizing plate having an antireflection effect and a viewing angle expansion effect can be obtained with the thickness of one polarizing plate, which is particularly preferable.

  In order to describe the present invention in detail, examples will be described below, but the present invention is not limited thereto. Unless otherwise specified, “part” and “%” are based on mass.

(Synthesis of perfluoroolefin copolymer (1))

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

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

(Preparation of sol liquid b)
After cooling to room temperature after the reaction, a sol solution b was obtained in the same manner as the sol solution a except that 6 parts of acetylacetone was added.

(Preparation of coating solution A for light scattering layer)
50 g of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (PET-30, manufactured by Nippon Kayaku Co., Ltd.) was diluted with 40 g of toluene. Further, 2 g of a polymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) was added and mixed and stirred. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.51.
Further, a 30% toluene dispersion of crosslinked polystyrene particles having an average particle size of 3.5 μm (refractive index 1.61, SX-350, manufactured by Soken Chemical Co., Ltd.) dispersed in this solution for 20 minutes at 10,000 rpm with a Polytron disperser. Add 13.3 g of 30% toluene dispersion of 1.7 g and crosslinked acrylic-styrene particles having an average particle size of 3.5 μm (refractive index 1.55, manufactured by Soken Chemical Co., Ltd.), and finally, fluorine-based surface modification 0.75 g of an agent (FP-149) and 10 g of a silane coupling agent (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to obtain a finished solution.
The mixed solution was filtered through a polypropylene filter having a pore diameter of 30 μm to prepare a coating solution A for a light scattering layer.
The liquid density of this coating composition was 0.99, and the density of the translucent fine particles was 1.06. Therefore, (σ−ρ) × d ² = 0.86.

(Preparation of coating solution B for light scattering layer)
285 g of commercially available zirconia-containing UV curable hard coat liquid (Desolite Z7404, manufactured by JSR Corporation, solid content concentration of about 61%, ZrO ₂ content of solid content of about 70%, polymerizable monomer, polymerization initiator contained), dipenta 85 g of a mixture of erythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was mixed, and further diluted with 60 g of methyl isobutyl ketone and 17 g of methyl ethyl ketone. Furthermore, 28 g of a silane coupling agent (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed and stirred. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.61.
Further, a 30% methyl isobutyl ketone dispersion of classified strengthened crosslinked PMMA particles (refractive index: 1.49, MXS-300, manufactured by Soken Chemical Co., Ltd.) having an average particle size of 3.0 μm was added to this solution at 10,000 rpm with a Polytron disperser. 34 g of a dispersion dispersed for 20 minutes was added, and then a 30% methyl ethyl ketone dispersion of silica particles having an average particle diameter of 1.5 μm (refractive index 1.46, Seahoster KE-P150, manufactured by Nippon Shokubai Co., Ltd.) 90 g of a dispersion dispersed at 10,000 rpm for 30 minutes was added, and finally 0.12 g of a fluorine-based surface modifier (FP-1) was mixed and stirred to obtain a finished solution.
The mixed solution was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution B for a light scattering layer.
The liquid density of the present coating composition is 1.15, and the density of the light-transmitting fine particles is PMMA: 1.18 and silica: 2.0. PMMA swells with a solvent in the coating composition, and the average particle diameter is Since it increased by about 30%, the apparent density was 1.17, and thus PMMA: (σ−ρ) × d ² = 0.30 and silica: 1.91.

(Preparation of coating solution C for light scattering layer)
In the light scattering layer coating solution B, instead of silica particles having an average particle diameter of 1.5 μm, classified reinforcing highly crosslinked PMMA particles having an average particle diameter of 1.5 μm (MXS-150H, a crosslinking agent ethylene glycol dimethacrylate, an amount of crosslinking agent of 30 %, A coating solution C for a light scattering layer was prepared in the same manner as the coating liquid A, including the addition amount, except that 120 g of 30% methyl ethyl ketone dispersion having a refractive index of 1.49) manufactured by Soken Chemical Co., Ltd. was used. .
The liquid density of the present coating composition was 1.15, and the density of the light-transmitting fine particles was 1.18, but both were swollen by the solvent in the coating composition, and the average particle size was increased by about 30%. Apparently, the density was 1.17, so 1.5 μm particles: (σ−ρ) × d ² = 0.076, 3 μm particles: (σ−ρ) × d ² = 0.30.

(Adjustment of coating solution A for low refractive index layer)
Thermally crosslinkable fluorine-containing polymer having a refractive index of 1.42 containing polysiloxane and hydroxyl group (JN7228A, solid content concentration 6%, manufactured by JSR Corporation), 15 g silica sol (silica, MEK-ST, average particle size 15 nm, solid Partial concentration 30%, Nissan Chemical Co., Ltd. 0.6 g, silica sol (silica, MEK-ST particle size difference, average particle size 45 nm, solid content concentration 30%, Nissan Chemical Co., Ltd.) 0.8 g, sol solution a 0.4 g, 3 g of methyl ethyl ketone and 0.6 g of cyclohexano were added, stirred, and then filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating solution A for a low refractive index layer. The refractive index of the layer formed with this coating solution was 1.43.

(Adjustment of coating liquid B for low refractive index layer)
In the coating liquid A for the low refractive index layer, the coating liquid including the addition amount was used except that 1.95 g of hollow silica sol (refractive index 1.31, average particle size 60 nm, solid content concentration 20%) was used instead of silica sol. In the same manner as A, a coating solution B for a low refractive index layer was prepared. The refractive index of the layer formed by this coating solution was 1.38.

(Preparation of coating solution C for low refractive index layer)
15.2 g of perfluoroolefin copolymer (1), silica sol (silica, MEK-ST with different particle size, average particle size 45 nm, solid content concentration 30%, manufactured by Nissan Chemical Co., Ltd.) 1.4 g, reactive silicone X-22-164B (trade name; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.3 g, sol solution a 7.3 g, photopolymerization initiator (Irgacure 907 (trade name), manufactured by Ciba Specialty Chemicals Co., Ltd.) 76 g, methyl ethyl ketone 301 g and cyclohexanone 9.0 g were added, and after stirring, the mixture was filtered through a polypropylene filter having a pore size of 5 μm to prepare a coating solution D for a low refractive index layer. The refractive index of the layer formed with this coating solution was 1.44.

(Adjustment of coating liquid D for low refractive index layer)
In the coating liquid C for the low refractive index layer, the coating liquid including the addition amount is used except that 1.95 g of hollow silica sol (refractive index 1.31, average particle size 60 nm, solid content concentration 20%) is used instead of silica sol. In the same manner as D, a coating solution D for a low refractive index layer was prepared. The refractive index of the layer formed by this coating solution was 1.40.

(Adjustment of coating liquid E for low refractive index layer)
In the coating liquid A for the low refractive index layer, the coating liquid A including the addition amount was used except that JTA113 (solid content concentration 6%, manufactured by JSR Corporation) was used instead of the thermally crosslinkable fluorine-containing polymer JN7228A. Similarly, a coating liquid E for a low refractive index layer was prepared. JTA113 is a thermally crosslinkable fluorine-containing polymer having a refractive index of 1.44, which is further improved in scratch resistance than JN7228A. The refractive index of the layer formed with this coating solution was 1.45.

[Example 1]
(1) Coating of light scattering layer A 80 μm-thick triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) is unrolled in a roll form, and the die coat shown by the following apparatus configuration and coating conditions The coating solution A for the light scattering layer was applied by the method, dried at 30 ° C. for 15 seconds and at 90 ° C. for 20 seconds, and then air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm under a nitrogen purge. The coating layer was cured by irradiating with ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 90 mJ / cm ² to form a 6 μm thick anti-glare light scattering layer and wound up. This is Example 1-1.
A light scattering layer was formed and wound in the same manner except that the light scattering layer coating liquid A was changed to light scattering layer coating liquids B and C and the wet coating amount was changed to 10 cc / m ² . The one coated with the light scattering layer coating liquid B is referred to as Comparative Example 1-1, and the one coated with the light scattering layer coating liquid C is referred to as Example 1-2.

Basic conditions: The slot die 13 has an upstream lip land length I _UP of 0.5 mm, a downstream lip land length I _LO of 50 μm, a length of the opening of the slot 16 in the web running direction of 150 μm, and the length of the slot 16 The one with a length of 50 mm was used. The gap between the upstream lip land 18a and the web W is 50 μm longer than the gap between the downstream lip land 18b and the web W (hereinafter referred to as an overbite length of 50 μm), and the gap between the downstream lip land 18b and the web W _GL was set to 50 μm. Further, the gap G _B between the gap G _S, and the back plate 40a and the web W between the side plate 40b and the web W in the vacuum chamber 40 were both 200 [mu] m. According to the liquid physical properties of each coating solution, light scattering layer: coating speed = 50 m / min, wet coating amount = 17 ml / m ² , low refractive index layer: coating speed = 40 m / min, wet coating amount = 5 ml / m Application was performed at m ² . The application width was 1300 mm and the effective width was 1280 mm.

(2) Coating of low refractive index layer The triacetyl cellulose film coated with the light scattering layer coating liquids A, B, and C is unwound again to apply the low refractive index layer. Liquid A was applied under the above basic conditions, dried at 120 ° C. for 150 seconds, further dried at 140 ° C. for 8 minutes, and then air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) at 240 W / cm under a nitrogen purge. Was used to irradiate ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 900 mJ / cm ² to form a low refractive index layer having a thickness of 100 nm and wound up.
(Saponification treatment of antireflection film)
After the film formation, the sample 1 was subjected to the following treatment.
A 1.5 mol / l aqueous sodium hydroxide solution was prepared and kept at 55 ° C. A 0.01 mol / l dilute sulfuric acid aqueous solution was prepared and kept at 35 ° C. The prepared antireflection film was immersed in the aqueous sodium hydroxide solution for 2 minutes, and then immersed in water to sufficiently wash away the aqueous sodium hydroxide solution. Subsequently, after being immersed in the dilute sulfuric acid aqueous solution for 1 minute, it was immersed in water to sufficiently wash away the dilute sulfuric acid aqueous solution. Finally, the sample was thoroughly dried at 120 ° C.
In this way, a saponified antireflection film was produced. These are referred to as Example 1-3, Comparative Example 1-2, and Example 1-4.

(Evaluation of light scattering film)
About the obtained film, the following items were evaluated. The results are shown in Table 1.

(1) Average reflectance The back side of the film was treated with a black ink after making the back surface, and the surface side was 380 to 380 with a spectrophotometer (manufactured by JASCO Corporation) in a state where the back side reflection was eliminated. Spectral reflectance at an incident angle of 5 ° was measured in the wavelength region of 780 nm. The arithmetic average value of the specular reflectance of 450-650 nm was used for the result.

(2) Light Scattering Variation 500 mm was cut in the longitudinal direction of a 1340 mm wide film, and the light scattering variation in the width direction was visually inspected in the transmission mode, and evaluated according to the following criteria.
Variations are extremely small, and unevenness cannot be seen visually: ◎
Small variation and almost no unevenness can be seen visually: ○
Slightly large variation and visually visible unevenness: △
Large variation and unevenness at a glance: ×

As shown in Table 1, Example 1-3 (antireflection film coated with coating solution A for light scattering layer, coating solution A for low refractive index layer), Example 1-4 (coating solution C for light scattering layer) The antireflective film coated with the coating liquid A for the low refractive index layer) was prepared in the same manner as in Examples 1-3 and 1-4 except that the coating liquid for the low refractive index layer was changed to BE. And evaluated. These are referred to as Example 1-5 to Example 1-12. The results are shown in Table 1. The coating solutions C and D for the low refractive index layer were coated, dried at 120 ° C. for 30 seconds, and then air-cooled with a 240 W / cm air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) under nitrogen purge A low refractive index layer was formed by irradiating ultraviolet rays at 400 mW / cm ² and an irradiation amount of 900 mJ / cm ² .

From the results shown in Table 1, the following is clear.
In the method for producing a light-scattering film of the present invention, since the sedimentation rate of the light-transmitting fine particles is controlled by satisfying the formula (1), the inside of the pocket, which is a problem particularly when applied by a die coating method, is used. There is no sedimentation of translucent fine particles on the film, and the obtained film is excellent in light scattering uniformity within the wide sample surface. In addition, the die coating method of the present invention has a high productivity because it is excellent in high-speed coating suitability particularly with a wet coating amount of 20 cc / cm ² or less.

In Examples 1-1 to 1-12, when the diluent solvent used in the coating liquids A and C for the light scattering layer has a solvent composition of toluene / cyclohexanone = 85/15 and toluene / cyclohexanone = 70/30 instead of toluene, As the ratio of cyclohexanone increased, the adhesion strength of the transparent support / light scattering layer was enhanced and the scratch resistance was improved.
In Examples 1-1 to 1-12, when b was used in place of the organosilane sol liquid a used in the low refractive index layer coating liquid, the temporal stability of the coating liquid was improved, and continuous coating was performed. The suitability for became higher.
Further, 10 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was added to the low refractive index layer coating liquids C and D. Improved significantly.

In Examples 1-1 to 1-12, an acrylic polymer (for the coating liquid A as a thickener was used so that the coating liquids A and C for the light scattering layer had a viscosity of 7 × 10 ⁻³ Pa · s. For molecular weight 75,000, manufactured by Mitsubishi Rayon) and coating liquid C, cellulose acetate butyrate having a molecular weight of 40,000 (CAB-531-1, manufactured by Eastman Chemical Co., Ltd.) is added to increase the viscosity. Went. The gap _GL between the downstream lip land 18b and the web W was set to 40 μm. As a result, it was found that the particle sedimentation was further improved and the particle sedimentation in a part of the liquid delivery pipe after 24 hours application observed in the coating solution before thickening was not observed, and the continuous productivity was further improved. .
As a result of adding a thickener and increasing the viscosity of the coating liquids A and C to 13 cp, it was confirmed that the particle sedimentation was further slowed in a stationary state, but the coating speed was only applied up to 30 m / min. The high-speed coating suitability was slightly inferior.

[Example 2]
80 μm-thick triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.), which was immersed in an aqueous 1.5 mol / L, 55 ° C. NaOH solution for 2 minutes, then neutralized and washed with water, and Examples 1 was adsorbed to polyvinyl alcohol using the light-scattering films (Example 1-1, Example 1-2) and the antireflection film (saponified: Examples 1-3 to 1-12) prepared in 1. A polarizing plate was prepared by adhering and protecting both sides of a polarizer prepared by stretching. Using these polarizing plates, a transmissive TN liquid crystal display device in which a light scattering layer or an antireflection layer is arranged on the outermost layer was produced. As a result, there was no reflection of external light, and the visibility was excellent. What was used had a better visibility since the amount of reflected external light was reduced and the contrast was improved.

[Example 3]
As the protective film on the liquid crystal cell side of the polarizing plate on the viewing side of the transmission type TN liquid crystal cell of Example 2 and the protective film on the liquid crystal cell side of the polarizing plate on the backlight side, a viewing angle widening film (wide view film SA 12B, When Fuji Photo Film Co., Ltd. was used, a liquid crystal display device with a very wide viewing angle in the vertical and horizontal directions, excellent visibility, and high display quality was obtained.
Further, using an automatic goniophotometer GP-5 type (manufactured by Murakami Color Research Laboratory Co., Ltd.), the film was placed perpendicular to the incident light, and the scattered light profile was measured in all directions. From this profile, the scattered light intensity at 30 ° C. with respect to an emission angle of 0 ° was obtained. Examples 1-2, 1-4, 1-9 to 1-12 (samples using the coating solution C for the light scattering layer) have a scattered light intensity of 30 ° with respect to an emission angle of 0 ° of 0.06%. The light diffusibility particularly improved the viewing angle in the downward direction and the yellowness in the left and right direction, and was a very good liquid crystal display device.
Further, when a 110 ppi high-definition cell is used as the transmission type TN liquid crystal cell of Example 2, particularly those using the samples of Examples 1-1, 1-3, and 1-5 to 1-8 are antiglare layers. The so-called glare caused by non-uniform enlargement / reduction of each pixel due to the lens effect was so high that the high-definition suitability was high.

It is sectional drawing which shows typically one preferable embodiment (layer structure of an antireflection film) of the light-scattering film of this invention. It is sectional drawing of the coater 10 using the slot die 13 which implemented this invention. (A) shows the cross-sectional shape of the slot die 13 of the present invention, and (B) shows the cross-sectional shape of the conventional slot die 30. It is a perspective view which shows the slot die 13 of the application | coating process which implemented this invention, and its periphery. It is sectional drawing which shows the pressure reduction chamber 40 and the web W which are adjoining. (The back plate 40a is integrated with the main body of the chamber 40) Same (back plate 40a fastened to chamber 40 with screw 40c)

Explanation of symbols

1 Light-scattering film (antireflection film)
2 Transparent Support 3 Light Scattering Layer 4 Low Refractive Index Layer 5 Translucent Fine Particle 10 Coater 11 Backup Roll W Web 13 Slot Die 14 Coating Solution 14a Bead 14b Coating 15 Pocket 16 Slot 17 Tip Lip 18 Land 18a Upstream Lip Land 18b Downstream lip land I _UP Land length I of upstream lip land 18a Land length of _LO downstream lip land 18b LO Over bit length (distance between downstream lip land 18b and web W of upstream lip land 18a Difference)
G _L Tip lip 17 and web W gap (downstream lip land 18b and web W gap)
30 the gap G _S side plate 40b and the web W between the conventional slot-die 31a upstream lip land 31b downstream lip land 32 pocket 33 slot 40 vacuum chamber 40a back plate 40b side plate 40c screws G _B back plate 40a and the web W Gap between

Claims (11)

In the method for producing a light scattering film having a light scattering layer on a transparent support,
A coating composition for the light scattering layer, comprising translucent fine particles, a translucent resin, and a solvent, wherein the settling rate of the translucent fine particles is controlled by satisfying the formula (1) The light scattering layer is coated on the transparent support by applying the composition from the slot of the tip lip of the slot die in close proximity to the surface of a continuously running web supported by a backup roll. The manufacturing method of the light-scattering film characterized by including the process to apply.
Formula (1) (σ−ρ) × d ² ≦ 1.5
(Where, σ: density of translucent fine particles (g / cm ² ), ρ: density of coating composition (g / cm ² ), d: average particle diameter of translucent fine particles (μm))   The σ, ρ, d after swelling satisfy the formula (1) when the translucent fine particles are swollen by the solvent in the coating composition. A method for producing a light-scattering film.   The translucent fine particles have an average particle diameter of 0.5 to 5 μm, the difference in refractive index between the translucent fine particles and the translucent resin is 0.01 to 0.2, and the translucency The method for producing a light-scattering film according to claim 1, wherein fine particles are contained in an amount of 3 to 30% by mass in the total solid content of the light-scattering layer.   The translucent fine particles are crosslinked polystyrene, crosslinked poly (acryl-styrene), crosslinked poly ((meth) acrylate), or a mixture thereof, and the solvent is at least one selected from ketones, toluene, xylene, and esters. It consists of a kind of solvent, The manufacturing method of the light-scattering film in any one of Claims 1-3 characterized by the above-mentioned.   The light scattering film is an antireflection film in which a low refractive index layer having a lower refractive index than that of the support is formed on the light scattering layer directly or via another layer. Item 5. A method for producing a light-scattering film according to any one of Items 1 to 4. By applying the land of the tip lip of the slot die close to the surface of the web supported by the backup roll and continuously running from the slot of the tip lip, on the transparent support, the light scattering layer, In the method for producing a light-scattering film in which a low refractive index layer or other layer is applied,
A slot die having a land length at a tip lip on the web traveling direction side of the slot die of 30 μm or more and 100 μm or less, and when the slot die is installed at a coating position, the tip lip on the web traveling direction side and the web 2. The coating is performed using an overbite-shaped slot die in which the gap between the tip end lip opposite to the web traveling direction and the gap between the web is 30 μm or more and 120 μm or less. The manufacturing method of the light-scattering film in any one of -5.   In the polarizing plate which bonds together the polarizing film and the two protective films which protect both the front side and back side of this polarizing film, the light scattering manufactured with the manufacturing method in any one of Claims 1-6 A polarizing plate characterized by using a conductive film as a protective film on one side.   Of the two protective films for forming the polarizing plate, the film other than the light-scattering film includes an optically anisotropic layer on the surface opposite to the surface to be bonded to the polarizing film. An optical compensation film having an optical compensation layer, wherein the optical anisotropic layer is a layer made of a compound having a discotic structural unit, and the disc surface of the discotic structural unit is inclined with respect to the protective film surface. The polarizing plate according to claim 7, wherein an angle formed by the disc surface of the discotic structural unit and the surface of the protective film changes in the depth direction of the optically anisotropic layer. .   An image display device comprising a light-scattering film produced by the production method according to claim 1.   A liquid crystal display device comprising at least one light-scattering film produced by the production method according to claim 1 or at least one polarizing plate according to claim 7 or 8.   The manufacturing method according to claim 1, wherein a polarizer is provided on both surfaces of the liquid crystal cell, and the liquid crystal display device has at least one phase difference compensation element between the liquid crystal cell and the polarizer. A liquid crystal display device comprising a light-scattering film manufactured in (1).

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