JP2007164151A - Optical film, antireflection film, polarizing plate, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film having excellent optical properties and a high surface hardness, and also to provide an antireflection film, a polarizing plate and an image display device using the optical film. <P>SOLUTION: The optical film has a light-diffusing layer containing at least one kind of resin particles having a particle size of from 0.5 μm to 5 μm and a binder matrix on a transparent support, wherein the resin particles have a compressive strength of from 2 to 10 kg/mm<SP>2</SP>. An antireflection film, a polarizing plate and an image display device are also disclosed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical film, an antireflection film using the optical film, a polarizing plate, and an image display device.

In recent years, liquid crystal display devices (LCDs) have been increased in screen size, and liquid crystal display devices provided with an optical film, for example, an antireflection film, have been increasing.
Antireflection films are used in various image display devices such as liquid crystal display devices (LCD), plasma display panels (PDP), electroluminescence displays (ELD), and cathode ray tube display devices (CRT) to reflect external light and In order to prevent a decrease in contrast due to reflection, it is arranged on the surface of the display. A light diffusing layer is installed as one means for imparting antireflection ability to the antireflection film. This layer usually contains particles, which reduce the reflection of the image, such as by imparting irregularities to the surface or scattering the reflected light on the particle surface.

Since the antireflection film is applied to the outermost surface of the display, as another function, high film hardness is required so as not to impair the visibility due to a scratch or a scratch.
As a film having high hardness, a high refractive index layer film having a reactive outer layer in the highly cross-linked core part (see, for example, Patent Document 1), and containing resin particles whose volume swelling rate is regulated to a certain value or less by containing a crosslinking agent A film (for example, see Patent Document 2), a film containing inorganic fine particles and defining the thickness of the hard coat layer within a certain range (for example, see Patent Document 3), etc. are disclosed. Improvement is demanded.
JP-A-7-92306 JP 2004-226832 A JP 2000-112379 A

  An object of the present invention is to stably provide an optical film having excellent optical performance and high surface hardness. Another object of the present invention is to provide an antireflection film using an optical film, a polarizing plate, and an image display device.

  The said subject was achieved by the optical film of the following structure, an antireflection film, a polarizing plate, and an image display apparatus.

(1) It has a light diffusion layer containing at least one kind of resin particles having a particle size of 0.5 μm to 5 μm and a binder matrix on a transparent support, and the compressive strength of the resin particles is 2 kgf / mm ² to
An optical film characterized by being 10 kgf / mm ² .
(2) The optical film as described in 1 above, wherein the center line average roughness (Ra) of the outermost surface on the light diffusion layer coating side is 0.12 μm or more.
(3) The optical film as described in 1 or 2 above, wherein the swelling rate after the resin particles are immersed in a dispersion solvent is 20% by volume or less.
(4) The resin particles are cross-linked with a bifunctional or higher monomer, and the content of the crosslinkable monomer is 15% by mass or more based on the total monomers for forming the resin particles. 4. The optical film according to any one of 3.
(5) The above 1 to 3, wherein the resin particles are crosslinked with a trifunctional or higher monomer, and the content of the crosslinkable monomer is 15% by mass or more based on the total monomers for forming the resin particles. 4. The optical film according to any one of 4 above.
(6) The optical film as described in any one of 1 to 5 above, wherein a difference in refractive index between the resin particles and the binder matrix is 0 to 0.20.
(7) The optical film as described in any one of (1) to (6) above, wherein the resin particles are resin particles obtained by polymerizing a (meth) acrylic acid ester monomer.
(8) The light diffusing layer contains 20 to 100% by mass of an epoxy resin having two or more epoxy groups in one molecule as a binder with respect to all binders. The optical film in any one.
(9) The image clarity according to JIS K7105 of the optical film is 5% to 50% when measured at an optical comb width of 0.5 mm, as described in any one of 1 to 8 above Optical film.
(10) The antireflection film, wherein the optical film according to any one of 1 to 9 is an antireflection film.
(11) A polarizing plate, wherein the antireflection film as described in 10 above is used for at least one of two protective films of a polarizing film.
(12) An image display device, wherein the optical film according to any one of 1 to 9, the antireflection film according to 10 or the polarizing plate according to 11 is disposed on an image display surface. .
(13) The image display device as described in (12) above, wherein the image display device is a TN, STN, IPS, VA or OCB mode transmissive, reflective or transflective liquid crystal display device.

  According to the present invention, by having resin particles having a specific compressive strength in the light diffusion layer, it is possible to provide a film having excellent optical performance such as antireflection performance and high surface hardness. In addition, since the optical film is used for an antireflection film, a polarizing plate, and an image display device, a high-quality image with excellent visibility can be obtained.

  In this specification, when a numerical value represents a physical property value, a characteristic value, or the like, the description “(numerical value I) to (numerical value II)” means “(numerical value I) to (numerical value II)”. The description “(meth) acryloyl” means “at least one of acryloyl and methacryloyl”. The same applies to “(meth) acrylate”, “(meth) acrylic acid” and the like.

Hereinafter, the present invention will be described in more detail. The optical film of the present invention has a light diffusion layer containing at least one kind of resin particles having a particle size of 0.5 μm to 5 μm and a binder matrix on a transparent support, and the compressive strength of the resin particles is 2 to 10 kgf / It is mm ² .

(Light diffusion layer)
The light diffusing layer according to the present invention includes a case where resin particles are included in a layer that affects optical performance. For example, this corresponds to a case where resin particles are contained in a high refractive index layer, a medium refractive index layer, a low refractive index layer, an antiglare layer, an antiglare antireflection layer, an intermediate layer, a hard coat layer, or the like.
The light diffusion layer is, for example, a main binder (translucent polymer formed by curing monomers and / or polymers with heat and / or ionizing radiation, etc.), translucent particles, and addition for increasing the film strength. And, if necessary, an inorganic fine particle filler for adjusting the refractive index, a polymer compound for controlling antiglare properties and coating liquid physical properties, and the like.
In the present invention, the improvement in the compressive strength of the resin particles is achieved because the elastic modulus of the entire film is increased by including in the light diffusion layer resin particles having an increased number of crosslinks compared to conventional low-crosslinked particles. The

  The thickness of the light diffusion layer is usually about 2 μm to 25 μm, preferably 3 μm to 20 μm, and more preferably 4 μm to 15 μm. When the thickness is in the above range, defects such as curl, haze value, and high cost are small, and adjustment of antiglare property, light diffusion effect, and the like is easy.

(Main binder)
The main matrix-forming binder for forming the light diffusion layer (hereinafter also simply referred to as a binder) is not particularly limited, but is a light-transmitting material formed by curing monomers and / or polymers with heat and / or ionizing radiation. It is preferably a light-transmitting polymer having a saturated hydrocarbon chain or a polyether chain as a main chain after curing with heat and / or ionizing radiation. The cured main binder polymer preferably has a crosslinked structure.

  The binder polymer having a saturated hydrocarbon chain as the main chain after curing includes an ethylenically unsaturated monomer and a polymer thereof (first group of compounds), and the polymer having a polyether chain as the main chain is an epoxy monomer. And polymers obtained by ring-opening thereof (compound of the second group) are preferred. Furthermore, a polymer of a mixture of these monomers is also preferable. Hereinafter, these compounds will be described in detail.

(First group of compounds)
As the binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure, a (co) polymer of monomers having two or more ethylenically unsaturated groups is preferable. In order to obtain a high refractive index, the monomer structure preferably contains at least one selected from an aromatic ring, a halogen atom other than fluorine, a sulfur atom, a phosphorus atom, and a nitrogen atom.

  As a monomer having two or more ethylenically unsaturated groups used in a binder polymer for forming a light diffusion layer, an ester of a polyhydric alcohol and (meth) acrylic acid {for example, ethylene glycol di (meth) Acrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) ) Acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-chlorohexanetetrameta Relate, polyurethane polyacrylate, polyester polyacrylate}, vinylbenzene and its derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone (eg, , Divinylsulfone), (meth) acrylamide (for example, methylenebisacrylamide) and the like.

  Furthermore, resins having two or more ethylenically unsaturated groups, such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins And oligomers or prepolymers such as polyfunctional compounds such as polyhydric alcohols. Two or more of these monomers may be used in combination, and the resin having two or more ethylenically unsaturated groups is preferably contained in an amount of 10 to 90% based on the total amount of the binder.

Polymerization of the monomer having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photoradical polymerization initiator or a thermal radical polymerization initiator. Therefore, a monomer having an ethylenically unsaturated group, a radical photopolymerization initiator or a thermal radical polymerization initiator, and resin particles, if necessary, an inorganic filler, a coating aid, other additives, and at least two kinds of organic solvents. A coating solution to be contained is prepared, and after coating the coating solution on a transparent support, it is cured by a polymerization reaction with ionizing radiation or heat to form a light diffusion layer. It is also preferable to perform ionizing radiation curing and thermal curing together. Commercially available compounds can be used as the photo and thermal polymerization initiators, and they are described in “Latest UV Curing Technology” (p. 159, publisher: Kazuhiro Takahisa, publisher; Technical Information Association, 1991). Issued) and Ciba Specialty Chemicals catalog.

(Second group of compounds)
In order to reduce the curing shrinkage of the cured film, it is preferable to use an epoxy compound described below. As these monomers having an epoxy group, monomers having two or more epoxy groups in one molecule are preferable, and examples thereof include JP-A Nos. 2004-264563, 2004-264564, and 2005-37737, Examples thereof include epoxy monomers described in JP-A-2005-37738, JP-A-2005-140862, JP-A-2005-140862, JP-A-2005-140863, and JP-A-2002-322430. Monomers having an epoxy group (preferably an epoxy resin having two or more epoxy groups in one molecule) are contained in an amount of 20 to 100% by mass with respect to all binders constituting the layer in order to reduce curing shrinkage. Preferably, the content is 35 to 100% by mass, and more preferably 50 to 100% by mass.

Photoacid generators that generate cations by the action of light for polymerizing epoxy monomers and compounds include ionic compounds such as triarylsulfonium salts and diaryliodonium salts, and nitrobenzyl esters of sulfonic acids. Nonionic compounds and the like can be used, and various known photoacid generators such as compounds described in “Organic Materials for Imaging” published by Bunshin Publishing Co., Ltd. (1997) can be used. . Among these, a sulfonium salt or an iodonium salt is particularly preferable, and PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , B (C ₆ F ₅ ) ₄ ^{− and the} like are preferable as a counter ion.

  These polymerization initiators are 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 monomers. . It is also preferable to use the above-mentioned first group of compounds and the second group of compounds in combination with the polymer compound described below.

(Polymer compound)
The light diffusion layer according to the present invention may contain a polymer compound. The polymer compound has already formed a polymer when it is added to the coating composition, and mainly adjusts the viscosity of the coating composition related to the dispersion stability (cohesiveness) of the resin particles and the polarity of the solidified product during the drying process. It is contained for the purpose of changing the agglomeration behavior of the resin particles by controlling the pH, or reducing drying unevenness in the drying process.

  Examples of the polymer compound include cellulose esters (for example, cellulose triacetate, cellulose diacetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate, and cellulose nitrate), urethane acrylates, polyester acrylates, ( (Meth) acrylic acid esters (for example, methyl methacrylate / (meth) methyl acrylate copolymer, methyl methacrylate / (meth) ethyl acrylate copolymer, methyl methacrylate / butyl (meth) acrylate copolymer) , Methyl methacrylate / styrene copolymer, methyl methacrylate / (meth) acrylic acid copolymer, polymethyl methacrylate, etc.), polystyrene and the like are preferably used.

From the viewpoint of the expression of the viscosity increasing effect of the coating composition and the film strength maintenance of the containing layer,
Preferably it is 3 to 40 mass% with respect to all the binders contained in the layer containing a high molecular compound, More preferably, it contains in the range of 5 to 30 mass%.
The molecular weight of the polymer compound is preferably from 30,000 to 400,000 in terms of mass average, more preferably from 50,000 to 300,000. When the molecular weight is within this range, the effect of increasing the viscosity of the coating composition is sufficiently exhibited, the dissolution time is short, and there are few insolubles.

The light diffusing layer is preferably formed by applying a coating solution to a support, and then carrying out light irradiation, electron beam irradiation, heat treatment, etc. to cause crosslinking or polymerization reaction. In the case of ultraviolet irradiation, ultraviolet rays emitted from light such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, etc. can be used.
Curing with ultraviolet rays is preferably performed by nitrogen purge or the like with an oxygen concentration of 4% by volume or less, more preferably 2% by volume or less, and most preferably 0.5% by volume or less.

(Resin particles)
The light diffusion layer contains resin particles having an average particle diameter of 0.5 μm to 5 μm, preferably 1 μm to 4.5 μm, and more preferably 1.5 μm to 4 μm. This increases the film hardness, scatters and weakens the external light reflected on the display surface, expands the viewing angle of the liquid crystal display (especially the downward viewing angle), and reduces the contrast even if the viewing angle changes. It is used for the purpose of making black-white reversal or hue change difficult to occur. When the average particle size is in the above range, the antiglare effect is exhibited and the graininess does not occur.

Compressive strength of the resin particles according to the present invention is ^{2kgf / mm 2 ~10kgf / mm 2} (19.6N / mm 2 ~98.1N / mm 2), 4kgf / mm 2 ~9kgf / mm 2 (39.2N / mm ^{2 to} 88.3 N / mm ² ), preferably 5 kgf / mm ^{2 to} 8 kgf / mm ² (49.0 N / mm ^{2 to} 78.5 N / mm ² ). Within this range, there is also a contribution to increasing the film hardness, and particle breakage due to deterioration in brittleness is unlikely to occur.

In the present invention, the compressive strength refers to the compressive strength when the particle diameter is deformed by 10%. The compressive strength when the particle size is deformed by 10% is the particle compressive strength (S10 strength), and is obtained by introducing the load when the particle size is deformed by 10% and the particle size before compression into the following equation. Value.
S10 strength (kgf / mm ² ) = 2.8 × load (kgf) / {(π × particle diameter (mm) × particle diameter (mm))
The measurement of the compressive strength is not particularly limited as long as it is a measurement method that requires the above parameters. For example, the compressive strength can be obtained by performing a compression test at a constant load speed of the resin particles alone using a micro compression tester MCT-W201 manufactured by Shimadzu Corporation.

In the present invention, the swelling rate is determined by dispersing resin particles in toluene at a concentration of 30% by mass, measuring the particle diameter (r1) measured within 3 hours after the dispersion is completed, and allowing the dispersion to stand at room temperature (25 ° C.). From the particle size (r2) when the increase in particle size stopped over time and the equilibrium state was reached, the following equation was used.
Swelling ratio (% by volume) = {(r2 / r1) ³ −1} × 100
The swelling rate is preferably 20% by volume or less, more preferably 15% by volume or less, and still more preferably 10% by volume or less.

  The refractive index difference between the resin particles and the translucent resin as the binder is preferably 0 to 0.20, preferably 0 to 0.10, from the viewpoint that the film does not become cloudy or obtains a light diffusion effect depending on the type. More preferably, 0 to 0.08 is particularly preferable.

From the same viewpoint, the preferable amount of the resin particles added to the translucent resin is determined. The content of the resin particles in the layer is preferably 3% by mass to 40% by mass, and more preferably 5% by mass to 25% by mass in the total solid content of the optical function layer. The optical functional layer means a layer such as a high refractive index layer, a middle refractive index layer, a low refractive index layer, an antiglare layer, an antiglare antireflection layer, an intermediate layer, or a hard coat layer.
The coating amount of the resin particles is preferably 10 mg / m ^{2 to} 10000 mg / m ² , more preferably 50 mg / m ^{2 to} 4000 mg / m ² , and most preferably 100 mg / m ² to the amount of particles in the formed optical function. It is contained in the containing layer so as to be 1500 mg / m ² .
The relationship between the particle diameter of the resin particles and the film thickness of the contained layer is preferably 20% to 110%, more preferably 30% to 100% of the film thickness of the layer containing the average particle diameter of the resin particles. 35% to 80% is most preferable. When the average particle size is within this range, the screen is excellent in blackening and the antiglare property is also excellent.
The particle size distribution of the particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution. The average particle size is calculated from the obtained particle distribution.

  The resin particles may be used in combination of two or more kinds of resin particles having different compositions, shapes, average particle diameters, dispersities, refractive indices and the like. When two or more types of resin particles are used, in order to effectively exert the refractive index control by mixing a plurality of types of particles, the resin particles having the highest refractive index and the resin particles having the lowest refractive index are used. The difference in refractive index is preferably 0.01 to 0.1 or less, particularly preferably 0.02 or more and 0.07 or less. Further, the antiglare property may be imparted with resin particles having a large particle size, and another optical characteristic may be imparted with resin particles having a small particle size. For example, it is possible to improve unevenness in luminance due to unevenness (contributing to antiglare property) on the film surface called glare, which is particularly problematic in an antireflection film for high-definition displays of 133 ppi or higher.

The crosslinking rate of the resin particles of the present invention is preferably higher for improving the film hardness, but from the viewpoint of avoiding particle hardness and deterioration of brittleness, the crosslinkable monomer content of the resin particles is 15% by mass or more, preferably 20% by mass to 95% by mass, and more preferably 30% by mass to 90% by mass is preferable for achieving both properties.
Further, the number of polymerizable functional groups per molecule of the monomer is preferably trifunctional or more, more preferably tetrafunctional or more from the viewpoint of increasing the crosslinking point.
Further, the gel fraction of the resin particles according to the present invention is preferably 80% by mass to 99% by mass for improving the film hardness. The gel fraction is determined by the following method.
After a certain amount of particle powder has been heated and stirred in methyl ethyl ketone for a certain period of time, the particles are separated by a filtration method, and the liquid after filtration is dried to obtain the residue mass. From this value, methyl ethyl ketone is obtained relative to the original mass. Calculate the ratio of the solid content that remains without eluting.

Specific examples of the crosslinkable monomer constituting the resin particles according to the present invention include styrene, divinylbenzene, trivinylbenzene, divinyltoluene, divinylxylene, ethyldivinylbenzene, divinylnaphthalene, divinylalkylbenzenes, divinylphenanthrene. , Aromatic monomers such as divinylbiphenyl, divinyldiphenylmethane, divinylbenzyl, divinylphenyl ether, divinyldiphenyl sulfide,
Oxygen-containing monomers such as divinylfuran, sulfur-containing monomers such as divinyl sulfide and divinyl sulfone, aliphatic monomers such as butadiene, isoprene and pentadiene,
Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol Di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, octanediol di (meth) acrylate, decanediol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) Acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol di (meth) acrylate , Dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, N, N'-methylenebis (meth) acrylamide, triallyl isocyanurate, triallylamine, tetraallyloxyethane, and hydroquinone, catechol, resorcinol And ester compounds of polyhydric alcohols such as sorbitol and acrylic acid or methacrylic acid. These may be used alone or in combination of two or more.
Among these, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, divinylbenzene, trivinylbenzene, divinylnaphthalene and the like are preferable. .

  Specific examples of the resin particles according to the present invention include, for example, crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles, crosslinked polystyrene particles, crosslinked methyl methacrylate-methyl acrylate copolymer particles, and crosslinked acrylate-styrene. Resin particles such as copolymer particle particles are preferred. Of these, crosslinked styrene particles, crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles, and the like are preferable.

The method for producing the resin particles according to the present invention may be produced by any method such as suspension polymerization, emulsion polymerization, soap-free emulsion polymerization, dispersion polymerization, and seed polymerization. These production methods are described in, for example, “Experimental Methods for Polymer Synthesis” (Takayuki Otsu and Masaaki Kinoshita, Chemical Dojinsha), pages 130 and 146 to 147, “Synthetic Polymers” 1 246 to 290, 31 to 108, etc., and Patent Nos. 2543503, 3508304, 2746275, 3521560, 3580320, JP-A-10-1561, JP-A-7-2908. Reference can be made to the methods described in JP-A-5-297506, JP-A-2002-145919, and the like.
For example, emulsion polymerization and suspension polymerization include, for example, a method in which a monomer is refined in an aqueous medium for polymerization. As dispersion-stabilizing surfactants, anionic surfactants such as dodecylbenzenesulfonate, dodecylsulfate, laurylsulfate, dialkylsulfosuccinate, and nonionics such as polyoxyethylene nonylphenyl ether and polyethylene glycol monostearate Surfactant etc. can be mentioned. Further, examples of the dispersion stabilizer include polymers and oligomers such as polyvinyl alcohol, sodium polyacrylate, hydrolyzate of styrene-maleic anhydride copolymer, sodium alginate, and a water-soluble cellulose derivative. In addition, in the method of performing an addition polymerization reaction initiated with an oil-soluble polymerization initiator using water as a dispersion medium in the presence of inorganic salts and / or dispersion stabilizers, examples of water-soluble salts include sodium chloride, potassium chloride, and calcium chloride. Magnesium sulfate or the like can also be used. Examples of the polymerization initiator include azobis compounds (azobisisobutyronitrile, azobis [cyclohexane-1-carbonitrile], etc.), peroxides (benzoyl peroxide, t-butyl peroxide, etc.) and the like.
Furthermore, a so-called multi-stage polymerization method is also preferred, in which a micropolymer is prepared in advance and the particles are impregnated to thicken the particles.

As the shape of the resin particles, either a true sphere or an indefinite shape can be used. The particle size distribution is preferably monodisperse particles because of the haze value, controllability of diffusibility, and uniformity of the coated surface. For example, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the proportion of the coarse particle is preferably 1% or less of the total number of particles, more preferably 0.1% or less. Yes, more preferably 0.01% or less. Particles having such a particle size distribution are obtained by classification after a normal synthesis reaction, and particles having a more preferable distribution can be obtained by increasing the number of classifications or increasing the degree of classification.

In order to increase the refractive index of the layer, the light diffusion layer is made of an oxide of at least one metal selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony, in addition to the above particles, It is also preferable to contain a fine inorganic filler having an average primary particle size of 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less. The fine inorganic filler is preferably sufficiently shorter than the wavelength of light as the particle size of the dispersion since the dispersion in which the filler is dispersed in the binder polymer has optically uniform material properties.
Conversely, in a light diffusion layer using resin particles having a high refractive index, it is also preferable to lower the refractive index of the binder in order to increase the difference in refractive index from the particles. For this purpose, it is also preferable to contain silica fine particles, hollow silica fine particles and the like. The preferred particle size is the same as that of the above-mentioned high refractive index fine inorganic filler.
Specific examples of the fine inorganic filler used for the light diffusion layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and SiO ₂ . TiO ₂ and ZrO ₂ are particularly preferable in terms of increasing the refractive index. The surface of the inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.
The addition amount of these fine inorganic fillers is preferably 10 to 90%, more preferably 20 to 80%, and particularly preferably 30 to 75% of the total mass of the layer to be contained.

(Low refractive index layer)
The low refractive index layer contains a fluorine-containing compound. In particular, it is preferable to construct a low refractive index layer mainly composed of a fluorine-containing compound. The low refractive index layer mainly composed of a fluorine-containing compound is usually positioned as the outermost layer of the antireflection film and also has a function as an antifouling layer. Here, “mainly containing a fluorine-containing compound” means that the mass ratio of the fluorine-containing compound is the largest among the components contained in the low refractive index layer, and the content of the fluorine-containing compound is It is preferable that it is 50 mass% or more with respect to the total mass of a low refractive index layer, and it is more preferable that 60 mass% or more is contained.

  The fluorine-containing compound of the low refractive index layer is preferably formed by heating a fluorine-containing compound having a crosslinkable or polymerizable functional group, or a crosslinking or polymerization reaction by ionizing radiation curing. The fluorine-containing compound may be a commercially available product and is not particularly limited, but a preferable composition is described below.

(Fluorine-containing compounds)
The refractive index of the fluorine-containing compound contained in the low refractive index layer is preferably 1.35 to 1.50. More preferably, it is 1.36-1.47, More preferably, it is 1.38-1.45.
Examples of the fluorine-containing compound include a fluorine-containing polymer, a fluorine-containing silane compound, a fluorine-containing surfactant, and a fluorine-containing ether.
Examples of the fluorine-containing polymer include those synthesized by crosslinking or polymerization reaction of ethylenically unsaturated monomers containing fluorine atoms. Examples of ethylenically unsaturated monomers containing fluorine atoms include fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole), Fluorinated vinyl ethers and esters of fluorine-substituted alcohols with acrylic acid or methacrylic acid are included.

As the fluorine-containing polymer, a copolymer comprising a repeating structural unit containing a fluorine atom and a repeating structural unit not containing a fluorine atom can also be used. The copolymer can be obtained by a polymerization reaction of an ethylenically unsaturated monomer containing a fluorine atom and an ethylenically unsaturated monomer not containing a fluorine atom.
Examples of the ethylenically unsaturated monomer containing no fluorine atom include olefin, acrylic ester, methacrylic ester, styrene and derivatives thereof, vinyl ether, vinyl ester, acrylamide, N-cyclohexyl acrylamide, etc.), methacrylamide and acrylonitrile.

Examples of the fluorine-containing silane compound include silane compounds containing a perfluoroalkyl group.
Fluorine-containing surfactants are those in which part or all of the hydrocarbon hydrogen atoms constituting the hydrophobic part are replaced by fluorine atoms, and the hydrophilic part is anionic, cationic, nonionic and amphoteric. Any of these may be used.
Examples of the fluorinated ether include compounds generally used as a lubricant, and examples thereof include perfluoropolyether.

As the fluorine-containing compound of the low refractive index layer, a fluorine-containing polymer into which a crosslinked or polymerized structure is introduced is particularly preferable. The fluorine-containing polymer into which a crosslinked or polymerized structure is introduced can be obtained by crosslinking or polymerizing a fluorine-containing compound having a crosslinked or polymerizable functional group.
The fluorine-containing compound having a crosslinkable or polymerizable functional group can be obtained by introducing a crosslinkable or polymerizable functional group as a side chain into a fluorine-containing compound having no crosslinkable or polymerizable functional group. Examples of the crosslinkable or polymerizable functional group include groups such as (meth) acryloyl, isocyanate, epoxy, aziridine, oxazoline, aldehyde, carbonyl, hydrazine, carboxyl, methylol, and active methylene. Furthermore, you may have groups, such as hydroxy, amino, and sulfo. Commercial products may be used for these compounds.

  The fluorine-containing compound of the low refractive index layer preferably contains as a main component a copolymer comprising a repeating unit derived from a fluorine-containing vinyl monomer and a repeating unit having a (meth) acryloyl group in the side chain. The component derived from the copolymer is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more, based on the total mass of the outermost layer. Below, the said copolymer preferable to be used for a low refractive index layer is demonstrated.

Fluorine-containing vinyl monomers include fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, etc.), (meth) acrylic acid moieties or fully fluorinated alkyl ester derivatives (eg, biscoat) 6FM (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd.), M-2020 (trade name, manufactured by Daikin Industries, Ltd.) and the like, and fully or partially fluorinated vinyl ethers, etc. are preferable. From the viewpoints of refractive index, solubility, transparency, availability, etc., hexafluoropropylene is particularly preferred.
The fluorine-containing vinyl monomer is preferably introduced so that the fluorine content of the copolymer is 20 to 60% by mass, more preferably 25 to 55% by mass, and particularly preferably 30 to 50% by mass.

The copolymer may have a repeating unit having a (meth) acryloyl group.
The repeating unit having a (meth) acryloyl group in the side chain preferably occupies 5 to 90% by mass, more preferably 30 to 70% by mass, and 40 to 60% by mass in the copolymer. It is particularly preferred.

In addition to the repeating unit derived from the fluorine-containing vinyl monomer and the repeating unit having a (meth) acryloyl group in the side chain, other vinyl monomers can be appropriately copolymerized with the copolymer. A plurality of these vinyl monomers may be combined depending on the purpose, and are preferably introduced in the range of 0 to 65 mol% in the copolymer, more preferably 0 to 40 mol%, particularly preferably 0. ˜30 mol%.
The vinyl monomer unit that can be used in combination is not particularly limited. For example, olefins, acrylic esters, methacrylic esters, styrene derivatives, vinyl ethers, vinyl esters, unsaturated carboxylic acids, acrylamides, methacrylamides, acrylonitrile. Derivatives and the like can be mentioned.

As a preferred form of a copolymer composed of a repeating unit derived from the fluorine-containing vinyl monomer used in the present invention and a repeating unit having a (meth) acryloyl group in the side chain, one represented by the following general formula (1) is exemplified. It is done.
General formula (1)

In the 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, linear or branched. , May have a ring structure, and may have a heteroatom selected from O, N, and S.
Preferred _{examples, * - (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 a connecting site on the polymer main chain side, and ** represents a connecting site on the (meth) acryloyl group side) And the like. 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 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. It can be appropriately selected from various viewpoints such as adhesion, Tg of polymer (contributing to film hardness), solubility in solvent, transparency, slipperiness, dustproof / antifouling property, and can be selected according to the purpose. You may be comprised by the some vinyl monomer.

  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 mol% of each constituent component, and represent values satisfying 30 ≦ x ≦ 60, 5 ≦ y ≦ 70, and 0 ≦ z ≦ 65. Preferably, 35 ≦ x ≦ 55, 30 ≦ y ≦ 60, and 0 ≦ z ≦ 20, and particularly preferably 40 ≦ x ≦ 55, 40 ≦ y ≦ 55, and 0 ≦ z ≦ 10.

Furthermore, what is represented by General formula (2) is mentioned as an especially preferable form of the said copolymer.
General formula (2)

In general formula (2), X, x, and y are each synonymous with general formula (1), and their preferred ranges are also the same.
n represents an integer of 2 ≦ n ≦ 10, preferably 2 ≦ n ≦ 6, and particularly preferably 2 ≦ n ≦ 4.
B represents 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.
z1 and z2 represent mol% of each repeating unit, and represent values satisfying 0 ≦ z1 ≦ 65 and 0 ≦ z2 ≦ 65. It is preferable that 0 ≦ z1 ≦ 30 and 0 ≦ z2 ≦ 10 respectively, and it is particularly preferable that 0 ≦ z1 ≦ 10 and 0 ≦ z2 ≦ 5. As the copolymer represented by the general formula (2), those satisfying 40 ≦ x ≦ 60, 30 ≦ y ≦ 60, and z2 = 0 are particularly preferable.

  Preferred specific examples and synthesis methods of the copolymer represented by the general formula (1) or (2) include those described in paragraphs [0043] to [0047] of JP-A-2004-45462. .

  In addition, a polysiloxane structure may be introduced into the fluorine-containing compound for the purpose of imparting antifouling properties. The introduction is preferably block copolymerization or graft copolymerization. A polysiloxane component is 0.5 mass%-10 mass% in a compound, Preferably it is 1 mass%-5 mass%.

  In the present invention, the concentration of the fluorine-containing compound in the coating solution is appropriately selected depending on the use, but is preferably 0.01% by mass to 60% by mass, more preferably 0.5 to 50% by mass, and particularly preferably. It is about 1% to 20% by mass.

The low refractive index layer is made up of fillers (for example, inorganic fine particles and organic fine particles), slip agents (polysiloxane compounds such as dimethyl silicone), organosilane compounds and derivatives thereof, binders, surfactants, etc. Additives can be included. In particular, it is preferable to add a filler (for example, inorganic fine particles and organic fine particles) and a slipping agent (polysiloxane compound such as dimethyl silicone).
Hereinafter, preferred fillers, slip agents and the like used for the low refractive index layer will be described.

(Preferable filler for low refractive index layer)
It is preferable to add a filler (for example, inorganic fine particles or organic fine particles) in terms of improving the physical strength (such as scratch resistance) of the low refractive index layer. As the filler added to the low refractive index layer, inorganic fine particles are preferable. Among them, silicon dioxide (silica) having a low refractive index, hollow silica, silica having pores, fluorine-containing particles (magnesium fluoride, calcium fluoride, fluorine). Barium fluoride) and the like are preferable. Particularly preferred are silicon dioxide (silica) and hollow silica. These may be subjected to chemical surface treatment.
The addition amount of the filler is preferably 5% by mass to 70% by mass, more preferably 10% by mass to 50% by mass with respect to the total mass of the low refractive index layer from the viewpoint of physical strength, avoidance of cloudiness, and the like. Especially preferably, it is 20 mass%-40 mass%.
The average particle diameter of the filler is preferably 20% to 100%, more preferably 30% to 80%, and particularly preferably 30% to 50% with respect to the film thickness of the low refractive index layer.
Two or more kinds of fillers may be used in combination.

When the filler added to the low refractive index layer is silicon dioxide fine particles, it is particularly preferable to use hollow silicon dioxide fine particles. The hollow silicon dioxide fine particles preferably have a refractive index of 1.17 to 1.45, more preferably 1.17 to 1.40, and still more preferably 1.17 to 1.37. Here, the refractive index of the hollow silicon dioxide fine particles represents the refractive index of the entire particle, and thereby the refractive index of the low refractive index layer can be lowered.
For hollow silicon dioxide fine particles, the void ratio x is expressed by the following formula (1), where a is the radius of the cavity in the particle and b is the radius of the outer shell of the particle.

Equation ^{(1) x = (4πa 3} /3) / (4πb 3/3) × 100

The porosity x is preferably 10 to 60%, more preferably 20 to 60%, and most preferably 30 to 60%.

(Preferable slip agent for low refractive index layer)
The slip agent is preferably added from the viewpoint of improving the physical strength (such as scratch resistance) and antifouling property of the low refractive index layer.
Examples of the slip agent include fluorine-containing ether compounds (perfluoropolyether and derivatives thereof), polysiloxane compounds (dimethylpolysiloxane and derivatives thereof), and the like. Polysiloxane compounds are preferred.
Preferable examples of the polysiloxane compound include those having a substituent at at least one of a terminal and a side chain of a compound containing a plurality of dimethylsilyloxy units as repeating units.
The compound containing a dimethylsilyloxy unit as a repeating unit may contain a structural unit (substituent) other than the dimethylsilyloxy unit. The substituents may be the same or different, and a plurality of substituents are preferable.
Examples of preferred substituents include groups containing (meth) acryloyl 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 the molecular weight of a slip agent, 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 Si atom content of a siloxane compound, it is preferable that it is 5 mass% or more, it is especially preferable that it is 10-60 mass%, and it is most preferable that it is 15-50 mass%.

Specific compounds of polysiloxane are commercially available, for example, KF-100T, X-22-169AS
, KF-102, X-22-3701IE, X-22-164B, X-22-164C, X-22-5002, X-22-173B, X-22-174D, X-22-167B, X-22 -161AS, X-22-174DX, X-22-2426, X-22-170DX, X-22-176D, X-22-1821 (manufactured by Shin-Etsu Chemical Co., Ltd.), AK-5, AK-30, AK-32 (manufactured by Toa Gosei Chemical Co., Ltd.), Silaplane F
M-0275, FM-0721, FM-0725, FM-7725, DMS-U22, RMS-033, RMS-083, UMS-182 (manufactured by Chisso Corporation) and the like. Moreover, it can also produce by introduce | transducing a crosslinking or a polymerizable functional group into the hydroxyl group, amino group, mercapto group, etc. which a commercially available polysiloxane compound contains.

  Specific examples of preferable polysiloxane compounds include those described in JP-A 2003-329804, [0041] to [0045], but are not limited thereto.

  The addition amount of at least one of the polysiloxane compound and its derivative is preferably 0.05 to 30% by mass, more preferably 0.1 to 20% by mass, based on the total solid content of the outermost layer.

The low refractive index layer is prepared by applying a paint in which at least one of the above-mentioned fluorine-containing compound and, if necessary, the above-mentioned filler, the above-mentioned polysiloxane compound and its derivative is dissolved or dispersed in a solvent. Is preferred.
Preferred solvents include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, butyl acetate, etc.), ethers (tetrahydrofuran, 1,4-dioxane, etc.), alcohols (methanol, ethanol, etc.) Isopropyl alcohol, butanol, ethylene glycol, etc.), aromatic hydrocarbons (toluene, xylene, etc.), water and the like.
Particularly preferred solvents are ketones, aromatic hydrocarbons and esters, and most preferred solvents are ketones. Of the ketones, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone are particularly preferable. The solvent preferably has a ketone solvent content of 10% by mass or more of the total solvent contained in the paint. Preferably it is 30 mass% or more, More preferably, it is 60 mass% or more.
Two or more kinds of solvents can be used in combination.

In the case of a fluorine-containing compound having a crosslinkable or polymerizable functional group, it is preferable to produce a low refractive index layer by crosslinking or polymerizing the fluorine-containing compound simultaneously with or after the application of the low refractive index layer.
As the radical polymerization initiator, those that generate radicals by the action of heat or those that generate radicals by the action of light are preferable. As these polymerization initiators, those described in the section of the layer can be used, and it is preferable to perform thermosetting or photoradical curing after coating in the same manner as the light diffusion layer. Moreover, if it has a functional group which crosslinks or polymerizes with a cation, it is preferable to carry out a crosslinking or polymerization reaction using a cationic polymerization initiator, particularly a photocationic polymerization initiator.

  As the binder, other than the fluorine-containing compound, for example, a polymer compound containing no fluorine, monomers having a polymerizable group, and the like may be used.

  The film thickness of the low refractive index layer is preferably 30 to 200 nm, more preferably 50 to 150 nm, and particularly preferably 60 to 120 nm. When the low refractive index layer is used as an antifouling layer, the film thickness is preferably 3 to 50 nm, more preferably 5 to 35 nm, and particularly preferably 7 to 25 nm.

In addition to the above components (fluorine-containing compounds, polymerization initiators, photosensitizers, fillers, slip agents, binders, etc.), the low refractive index layer contains surfactants, antistatic agents, coupling agents, and thickeners. Agents, anti-coloring agents, coloring agents (pigments, dyes), antifoaming agents, leveling agents, flame retardants, ultraviolet absorbers, infrared absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modifiers, etc. Can also be added. Furthermore, in the low refractive index layer, an organosilane compound represented by the following general formula (a), and
It is also preferable to contain a compound selected from the group consisting of derivatives thereof (hydrolyzate and crosslinked silicon compound produced by condensation of the hydrolyzate).

(Various characteristics of low refractive index layer)
The low refractive index layer preferably has a surface dynamic friction coefficient of 0.25 or less in order to improve the physical strength of the optical film. The measurement conditions for the dynamic friction coefficient are as described below.
The contact angle with respect to water on the surface of the low refractive index layer is preferably 90 ° or more. More preferably, it is 95 ° or more, and particularly preferably 100 ° or more.
The haze of the low refractive index layer is preferably as low as possible. It is preferably 3% or less, more preferably 2% or less, and particularly preferably 1% or less.

  The strength of the low refractive index layer is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test according to the conditions described below. Further, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

  The refractive index of the low refractive index layer is preferably 1.20 to 1.55. More preferably, it is 1.30-1.50, More preferably, it is 1.35-1.48, Most preferably, it is 1.37-1.45.

(Antistatic layer)
In the optical film of the present invention, in order to prevent dust (dust etc.) from adhering to the surface, tin oxide, antimony-doped tin oxide (ATO), indium oxide, tin-doped indium oxide (ITO) is used as a conductive material. It is also preferred to use an antistatic layer using zinc oxide, zinc oxide doped with aluminum, or the like. The dust resistance is expressed by lowering the surface resistance value of the surface. The surface resistance value is preferably 1 × 10 ¹³ Ω / □ or less, more preferably 1 × 10 ¹² Ω / □ or less, and further preferably 1 × 10 ¹⁰ Ω / □ or less.
The antistatic layer is preferably provided between the antiglare layer and the low refractive index layer, or between the transparent support and the antiglare layer.

(About other coating layers)
In the optical film of the present invention, it is also preferable to provide a hard coat layer between the transparent support and the outermost layer in order to impart physical strength.
The hard coat layer is preferably formed by a crosslinking or polymerization reaction of an ionizing radiation curable compound. For example, a coating containing ionizing radiation-curable polyfunctional monomers or polyfunctional oligomers such as (meth) acryloyl group, vinyl group, styryl group, allyl group, etc. is applied on a transparent support and formed by crosslinking or polymerization reaction. can do.

(Transparent support)
The transparent support is preferably a plastic film. As the plastic film, cellulose ester (eg, triacetyl cellulose, diacetyl cellulose, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, nitrocellulose), polyamide, polycarbonate, polyester (eg, polyethylene terephthalate, polyethylene naphthalate, poly-1, 4-cyclohexanedimethylene terephthalate, polyethylene-1,2-diphenoxyethane-4,4′-dicarboxylate, polybutylene terephthalate), polystyrene (eg, syndiotactic polystyrene), polyolefin (eg, polypropylene, polyethylene, poly Methylpentene), polysulfone, polyethersulfone, polyarylate, polyetherimide, polymethylmethacrylate And polyether ketones. Triacetyl cellulose, polycarbonate, polyethylene terephthalate and polyethylene naphthalate are preferable, and by containing a retardation reducing compound, Re ₍ λ ₎ and Rth ₍ λ ₎ defined by the following formulas (I) and (II ₎ are: A cellulose acylate film characterized by satisfying the following formulas (III) and (IV) may be used.
(I) Re ₍ λ ₎ = (nx−ny) × d
(II) Rth ₍ λ ₎ = {(nx + ny) / 2−nz} × d
(III) 0 ≦ Re ₍₆₃₀₎ ≦ 10 and | Rth ₍₆₃₀₎ | ≦ 25
(IV) | Re ₍₄₀₀₎ −Re ₍₇₀₀₎ | ≦ 10 and | Rth ₍₄₀₀₎ −Rth ₍₇₀₀₎ | ≦ 35
[Wherein, Re ₍ λ ₎ is a front retardation value (unit: nm) at a wavelength λnm, and Rth ₍ λ ₎ is a retardation value (unit: nm) in a film thickness direction at a wavelength λnm. Further, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the thickness of the film. That's it. Of these, triacetylcellulose is preferred when used in a liquid crystal display device.

  When the transparent support is a triacetyl cellulose film, a triacetyl cellulose dope prepared by dissolving triacetyl cellulose in a solvent is prepared by a single layer casting method or a multi-layer co-casting method. A cellulose film is preferred.

In particular, from the viewpoint of environmental conservation, a triacetyl cellulose film prepared using a triacetyl cellulose dope prepared by dissolving triacetyl cellulose in a solvent substantially free of dichloromethane by a low temperature dissolution method or a high temperature dissolution method is preferable. .
The triacetylcellulose film preferably used in the present invention is exemplified in the Japan Society for Invention and Innovation (public technical number 2001-1745).

The film thickness of the transparent support is not particularly limited, but the film thickness is preferably 1 to 300 μm, preferably 30 to 150 μm, particularly preferably 40 to 120 μm, and most preferably 40 to 100 μm.
The light transmittance of the transparent support is preferably 80% or more, and more preferably 86% or more.
The haze of the transparent support is preferably low. It is preferably 2.0% or less, and more preferably 1.0% or less.
The refractive index of the transparent support is preferably 1.40 to 1.70.

An infrared absorber or an ultraviolet absorber may be added to the transparent support. The addition amount of the infrared absorber is preferably 0.01 to 20% by mass of the transparent support, and more preferably 0.05 to 10% by mass.
In addition, an inert inorganic compound particle may be added to the transparent support as a slipping agent. Examples of the inorganic _{compound, SiO 2, TiO 2, BaSO} 4, CaCO 3, talc and kaolin.

  A surface treatment may be performed on the transparent support. Examples of the surface treatment include chemical treatment, mechanical treatment, corona discharge treatment, flame treatment, ultraviolet irradiation treatment, high frequency treatment, glow discharge treatment, active plasma treatment, laser treatment, mixed acid treatment and ozone oxidation treatment. Glow discharge treatment, ultraviolet irradiation treatment, corona discharge treatment and flame treatment are preferred, and glow discharge treatment and corona discharge treatment are particularly preferred.

(Organosilane compound)
Any layer on the transparent support containing at least one compound selected from organosilane compounds and derivatives thereof in terms of improving the physical strength of the film (such as scratch resistance) and the adhesion between the film and the layer adjacent to the film. It is preferable to add to.

  As the organosilane compound and derivatives thereof, compounds represented by the following general formula (a) and derivatives thereof can be used. Preferred are organosilane compounds containing a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, an alkoxysilyl group, an acyloxy group, and an acylamino group, and particularly preferred are an epoxy group and a polymerizable acyloxy group (( (Meth) acryloyl, etc.), polymerizable acylamino groups (acrylamino, methacrylamino, etc.), and alkyl groups.

Formula _{^{(a) :( R 10) S}} -Si (Z) 4-S

In the general formula (a),
R ¹⁰ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. As an alkyl group, a C1-C30 alkyl group is preferable, More preferably, it is C1-C16.
Z represents a hydroxyl group or a hydrolyzable group. Z is 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 (such as Cl, Br, or I), or R ^2. COO (R ² is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples include CH ₃ COO, C ₂ H ₅ COO, etc.), preferably an alkoxy group, particularly preferably. A methoxy group or an ethoxy group; s represents an integer of 1 to 3, and is preferably 1 or 2.

When R ¹⁰ and Z there are a plurality, a plurality of R ¹⁰ and Z may be different from each other be the same.
There are no particular limitations on the substituents contained in R ^10, a halogen atom, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group (methyl, ethyl, i- propyl, propyl, t- butyl, etc.), an aryl group , Aromatic heterocyclic groups, alkoxy groups, aryloxy, alkylthio groups, arylthio groups, alkenyl groups, acyloxy groups, alkoxycarbonyl groups, aryloxycarbonyl groups, carbamoyl groups, acylamino groups, cycloalkyl groups, and the like. The group may be further substituted.

The general formula (a) is also preferably an organosilane compound having a vinyl polymerizable substituent represented by the following general formula (b).
General formula (b)

In the general formula (b),
R ₂ represents a hydrogen atom, a methyl group, a methoxy group, an alkoxycarbonyl group, a cyano group, a fluorine atom, or a chlorine atom. A hydrogen atom, a methyl group, a methoxy group, a methoxycarbonyl group, a cyano group, a fluorine atom, and a chlorine atom are preferable, a hydrogen atom, a methyl group, a methoxycarbonyl group, a fluorine atom, and a chlorine atom are more preferable, and a hydrogen atom and a methyl group Is particularly preferred.
Y represents a single bond, * -COO-**, * -CONH-**, or * -O-**, preferably a single bond, * -COO-**, or * -CONH-**. Bonds or * -COO-** are more preferred, and * -COO-** is particularly preferred. * Represents a position bonded to ═C (R ₂ ) —, and ** represents a position bonded to L.

  L represents a divalent linking chain. Specifically, a substituted or unsubstituted alkylene group or a substituted or unsubstituted arylene group is preferable. Examples of the substituent include a halogen atom, 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.

l represents a number (molar fraction) satisfying l = 100-m, and m represents a number (molar fraction) of 0 to 50. As for m, the number of 0-40 is more preferable, and the number of 0-30 is especially preferable.
R _{3 to} R ₅ represent a monovalent group, preferably a halogen atom, a hydroxyl group, an unsubstituted alkoxy group, or an unsubstituted alkyl group. R _{3 to} R ₅ are more preferably a chlorine atom, a hydroxyl group, or an unsubstituted alkoxy group having 1 to 6 carbon atoms, more preferably a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms, and a hydroxyl group or methoxy group. Particularly preferred is a group.
R ₆ represents a hydrogen atom or an alkyl group. The alkyl group is preferably a methyl group or an ethyl group. R ₆ is particularly preferably a hydrogen atom or a methyl group.
R ₇ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. As an alkyl group, a C1-C30 alkyl group is preferable, More preferably, it is C1-C16.
R _{4, R 5,} and _{when R 7} there are a plurality, even more of _R 4, _{R 5,} and _{R 7} are respectively the same or different.

  Two or more compounds of the general formula (a) may be used in combination. In particular, the compound of the general formula (b) is synthesized using two kinds of compounds of the general formula (a) as starting materials. Specific examples of the starting materials for the compounds represented by general formula (a) and general formula (b) are shown below, but the present invention is not limited thereto.

M-48: CH ₃ —Si (OCH ₃ ) ₃
M-49: C ₂ H ₅ —Si (OCH ₃ ) _{3
M-50: t-C 4} H 9 -Si (OCH 3) 3

  Of these, (M-1), (M-2), (M-25), (M-48), and (M-49) are particularly preferable.

  In order to obtain the effect of the present invention, the content of the organosilane containing the vinyl polymerizable group in the hydrolyzate of organosilane and / or its partial condensate is preferably 30% by mass to 100% by mass, More preferably, it is more preferably from 100% by weight to 100% by weight, even more preferably from 70% by weight to 100% by weight, and particularly preferably from 90% by weight to 100% by weight. From the viewpoints of solid content generation, liquid turbidity, deterioration of pot life, control of molecular weight, etc., and performance when polymerized due to low content of polymerizable groups (for example, scratch resistance of antireflection film) The content of the organosilane containing a vinyl polymerizable group is preferably 30% by mass or more.

The sol component used in the present invention is prepared by hydrolysis and / or partial condensation of the organosilane.
In at least one of the hydrolyzate of organosilane and the partial condensate thereof according to the present invention, the mass average molecular weight of the hydrolyzate of organosilane containing a vinyl polymerizable group and the partial condensate thereof is less than 300. When excluding the above components, 450 to 20000 is preferable.

  Preferred layers for adding the organosilane compound are an antistatic layer, a hard coat layer, an antiglare layer, a light diffusion layer, a high refractive index layer, a low refractive index layer, and an outermost layer, more preferably a hard coat layer. , An antiglare layer, a light diffusion layer, a low refractive index layer, and an outermost layer, particularly preferably an outermost layer and an adjacent layer of the outermost layer.

(Optical film formation method, etc.)
In the present invention, each layer constituting the optical film is preferably prepared by a coating method. When formed by coating, each layer is formed by dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, micro gravure coating or extrusion coating (US Pat. No. 2,681, 294 specification) or a die coating method (described in Japanese Patent Application Laid-Open Nos. 2003-20097, 2003-211052, 2003-236434, 2003-260400, 2003-260402, etc.). . Two or more layers may be applied simultaneously. For the simultaneous application method, US Pat. Nos. 2,761,791, 2,941,898, 3,508,947, 3,526,528 and Yuji Harasaki, “Coating Engineering ", page 253, Asakura Shoten (1973). Wire bar coating, gravure coating, micro gravure coating and die coating are preferred. In particular, the micro gravure coating method and the die coating method are preferable, and the die coating method is most preferable.

  The micro gravure coating method is a gravure roll having a diameter of about 10 to 100 mm, preferably about 20 to 50 mm and having a gravure pattern engraved on the entire circumference, below the support and in the transport direction of the support. In addition, the coating method is characterized in that the coating is reversely rotated, the excess coating solution is scraped off from the surface of the gravure roll by a doctor blade, and a fixed amount of coating solution is transferred to the support.

  In the die coating method, a coating film is formed on a web by applying a coating liquid as a bead from a slot die in which pockets are formed on a web that is continuously supported by a backup roller. By appropriately adjusting the distance between the tip of the slot die and the web on the upstream side and the downstream side of the slot member with respect to the web traveling direction, it is possible to accurately apply a wet film thickness of several tens of μm or less.

  When each layer of the optical film is prepared by a coating method, it is preferable to add a surface conditioner to the coating material used for preparing the layer. Hereinafter, the surface conditioner will be described.

(Surface improver)
In order to improve the surface failure (coating unevenness, drying unevenness, point defect, etc.), the paint used for producing any layer on the transparent support of the present invention is at least one of fluorine and silicone. It is preferable to add such a surface conditioner.

The surface conditioner preferably changes the surface tension of the paint by 1 mN / m or more. Here, the surface tension of the paint changes by 1 mN / m or more when the surface tension of the paint after the addition of the surface conditioner is added, including the concentration process during coating / drying. It means that it changes by 1 mN / m or more as compared with the surface tension of the paint.
Preferably, it is a surface improver that has an effect of lowering the surface tension of the paint by 1 mN / m or more, more preferably a surface improver that lowers by 2 mN / m or more, and particularly preferably a surface improver that lowers by 3 mN / m or more.

Preferable examples of the fluorine-based surface improving agent include compounds containing a fluoroaliphatic group (abbreviated as “fluorine surface improving agent”). In particular, an acrylic resin, a methacrylic resin, and a vinyl monomer copolymerizable with the repeating unit corresponding to the monomer of the following general formula (i) and the repeating unit corresponding to the monomer of the following general formula (ii) And a copolymer are preferred.
Such monomers include Polymer Handbook 2nd ed. , J .; Brandrup, Wiley lnterscience (1975) Chapter
It is preferable to use those described in r 2, Page 1-483.
For example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. I can give you.

Formula (i)

In the general formula (i), R ²¹ represents a hydrogen atom, a halogen atom or a methyl group, more preferably a hydrogen atom or a methyl group. X ² represents an oxygen atom, a sulfur atom or —N (R ²² ) —, more preferably an oxygen atom or —N (R ²² ) —, and particularly preferably an oxygen atom. R ²² represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, particularly preferably a hydrogen atom or a methyl group. a represents an integer of 1 to 6, more preferably 1 to 3, and particularly preferably 1. b represents an integer of 1 to 18, 4 to 12 is more preferable, and 6 to 8 is particularly preferable.
Two or more types of fluoroaliphatic group-containing monomers represented by the general formula (i) may be contained in the fluorine-based surface improver as a constituent component.

  Formula (ii)

In the general formula (ii), 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 particularly preferably an oxygen atom. R ²⁵ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, particularly preferably a hydrogen atom or a methyl group.
R ²⁴ is a hydrogen atom, a substituted or unsubstituted straight-chain having 1 to 20 carbon atoms, branched or cyclic alkyl group, polyalkyl group containing (alkyleneoxy) group, or a substituted or unsubstituted aromatic group (e.g., 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 in total is more preferable, and a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms is still more preferable. The poly (alkyleneoxy) group will be described below.

Poly (alkyleneoxy) group, - (OR) - a group in which a repeating unit, R represents an alkylene group having 2 to 4 carbon atoms, such as _{-CH 2 CH 2 -, - CH} 2 CH 2 CH ₂ −
_{, -CH (CH 3) CH 2} -, - CH (CH 3) CH (CH 3) - and the like.
The oxyalkylene units (-OR-) in the poly (oxyalkylene) group may be the same as in poly (oxypropylene), and two or more different oxyalkylenes are randomly distributed. It may be a linear or branched oxypropylene or oxyethylene unit, or a linear or branched oxypropylene unit block or an oxyethylene unit block. May be.

In the fluorine-based surface improver used in the present invention, the amount of the fluoroaliphatic group-containing monomer represented by the general formula (i) with respect to the total amount of monomers used for forming the fluorine-based surface improver is 50 mol% or more. It is preferable that there is, more preferably 70 to 100 mol%, particularly preferably in the range of 80 to 100 mol%.

The preferred weight average molecular weight of the fluorine-based surface improver used in the present invention is preferably 3000 to 100,000, more preferably 6,000 to 80,000, and still more preferably 8,000 to 60,000.
Furthermore, the preferable addition amount of the fluorine-type surface improving agent used by this invention is the range of 0.001-5 mass% with respect to the coating material of the layer to add, Preferably it is the range of 0.005-3 mass%. More preferably, it is the range of 0.01-1 mass%.

  Hereinafter, although the example of the specific structure of the fluorine-type surface improvement agent by this invention is shown, this invention is not limited to these. In addition, the number in a formula shows the molar ratio of each monomer component. Mw represents a mass average molecular weight.

The surface conditioner of the present invention includes ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ester solvents (ethyl acetate, butyl acetate, etc.),
It is preferable to use for paints containing ethers (tetrahydrofuran, 1,4-dioxane, etc.) and aromatic hydrocarbon solvents (toluene, xylene, etc.).

  In the coating of the layer formed on the transparent support, it is particularly preferable to add a surface conditioner to form a hard coat layer, an antiglare layer, an antistatic layer, a high refractive index layer, and a low refractive index layer. The paint for forming a hard coat layer and an antiglare layer is particularly preferred.

(Physical performance of optical film)
In the optical film of the present invention, the center line average roughness (Ra) of the outermost surface on the side on which the light diffusion layer is coated is preferably 0.12 μm or more from the viewpoint of providing appropriate antiglare properties, and preferably 0.15 μm to 0. .35 μm is more preferable, and 0.18 μm to 0.30 μm is even more preferable. Within this range, it is preferable because the reflection of light on the back surface is not dazzling when the display is viewed and the whiteness of the black image is small.
Centerline average roughness (Ra) is a numerical value defined by JIS B0601-1982. Also, Jiro Nara, Techno Compact Series (6) "Measurement and Evaluation Method of Surface Roughness" (Comprehensive Technology Co., Ltd.) Center).
This index is a value related to the antiglare property of the antireflection film, and is mainly controlled by the resin particle size, dispersion degree, particle frequency, cohesiveness, layer thickness, drying conditions, etc. contained in the light diffusion layer. .

The optical film of the present invention has an image sharpness according to JIS K7105 with an optical comb width of 0.5 m.
When measured by m, it is preferably 5% to 50%, more preferably 10% to 40%, in order to reduce the glare of the reflected light and reduce the whitening of the black image.
In addition, the optical film of the present invention has a light amount I ⁴⁵ ° reflected in a direction inclined + 45 ° with respect to the incident light amount I ₀ inclined by −60 ° with respect to the vertical direction from the light diffusion layer side. It is preferable to satisfy the above condition in order to reduce whitening of the black image.
Formula (11) 5.0 ≧ −LOG ₁₀ (I ⁴⁵ ° / I ₀ ) ≧ 4.0

The strength of the optical film of the present invention is preferably 4H or more, preferably 5H or more in the pencil hardness test according to JIS K5400, except that the surface hardness of the light diffusion layer coating side is as follows. More preferably, it is most preferably 6H or more. (Room temperature at 25 ° C, relative humidity 60% RH for 2 hours or more. Load 500g)
In the optical film of the present invention, in order to improve physical strength (such as scratch resistance), the dynamic friction coefficient of the surface having the coated outermost layer is preferably 0.25 or less. The coefficient of dynamic friction is as follows. When a load of 0.98 N is applied to a stainless hard sphere having a diameter of 5 mm and the surface having the outermost layer is moved at a speed of 60 cm / min, the surface having the outermost layer and the stainless hard sphere having a diameter of 5 mm The coefficient of dynamic friction between Preferably it is 0.17 or less, Most preferably, it is 0.15 or less.
Further, in order to improve the antifouling performance, the optical film preferably has a contact angle with water of the surface having the outermost layer of 80 ° or more. More preferably, it is 90 ° or more, and particularly preferably 100 ° or more. Further, it is desirable that the contact angle of the surface of the low refractive index layer with respect to water does not change before and after the saponification treatment described later, and the amount of change before and after the saponification treatment is preferably within 10 °, more preferably within 5 °.
Furthermore, the haze of the optical film of the present invention is preferably 0.5 to 60%, more preferably 1 to 50%, and most preferably 1 to 40%.
Furthermore, the reflectance of the optical film of the present invention is preferably as low as possible, preferably 3.0% or less, more preferably 2.5% or less, still more preferably 2.0% or less, and particularly preferably 1.5% or less. is there.

(Protective film for polarizing plate)
The optical film of the present invention can be used as a protective film for a polarizing film (protective film for polarizing plate). In this case, the contact angle with respect to water of the surface of the transparent support opposite to the side having the outermost layer, that is, the surface to be bonded to the polarizing film is preferably 40 ° or less. More preferably, it is 30 ° or less, and particularly preferably 25 ° or less. Setting the contact angle to 40 ° or less is effective in improving the adhesion with a polarizing film containing polyvinyl alcohol as a main component. This contact angle can be adjusted by the following saponification treatment conditions.

  As the transparent support of the antireflection film used as the protective film for polarizing plate, it is particularly preferable to use a triacetyl cellulose film.

The following two methods are mentioned as a method of producing the protective film for polarizing plates in this invention.
(1) On one surface of the saponified transparent support, each of the above layers (eg, antistatic layer, hard coat layer, antiglare layer as light diffusion layer, low refractive index layer, high refractive index layer, A method of coating the outermost layer.
(2) After coating each of the above layers (eg, antistatic layer, hard coat layer, antiglare layer, low refractive index layer, outermost layer, etc.) on one surface of the transparent support, the side to be bonded to the polarizing film Saponification treatment method.

  The saponification treatment is carried out after antireflection performance is imparted on the protective film, whereby the cost can be further reduced, and the method (2) is particularly preferable in that the protective film for polarizing plate can be produced at a low cost.

Protective films for polarizing plates have optical performance (low reflection performance, antiglare performance, etc.), physical performance (such as scratch resistance), chemical resistance, antifouling performance (contamination resistance, etc.), and weather resistance (moisture and heat resistance, light resistance). ) And dustproof performance, it is preferable to satisfy the performance described in the optical film of the present invention.
Accordingly, the surface resistance value of the surface having the outermost layer is preferably 1 × 10 ¹³ Ω / □ or less, more preferably 1 × 10 ¹² Ω / □ or less, and 1 × 10 ¹⁰ Ω / □. More preferably, it is as follows.
The coefficient of dynamic friction on the surface having the outermost layer is preferably 0.25 or less. Preferably it is 0.17 or less, Most preferably, it is 0.15 or less.
Further, the contact angle with respect to water on the surface having the outermost layer is preferably 90 ° or more. More preferably, it is 95 ° or more, and particularly preferably 100 ° or more.

(Saponification treatment)
The saponification treatment is preferably carried out by a known method, for example, by immersing the transparent support or the optical film in an alkali solution for an appropriate time.
The alkaline liquid is preferably a potassium hydroxide aqueous solution and / or 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 30-70 degreeC, Most preferably, it is 40-60 degreeC.
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 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 adhesion with a polarizing film containing polyvinyl alcohol as a main component.
The saponification treatment is preferably carried out so that the contact angle with water on the surface of the transparent support opposite to the side having the antiglare layer or the low refractive index layer is 40 ° or less. More preferably, it is 30 ° or less, particularly preferably 25 ° or less.

(Polarizer)
The polarizing plate of this invention has the optical film of this invention in at least one of the protective film (protective film for polarizing plates) of a deflection | deviation film | membrane. As described above, the polarizing plate protective film has a water contact angle of 40 ° or less on the surface of the transparent support opposite to the side having the outermost layer, that is, the surface to be bonded to the polarizing film. preferable.

By using the optical film of the present invention as a protective film for a polarizing plate, a polarizing plate having an antireflection function can be produced, and the cost can be greatly reduced and the display device can be thinned.
Further, the polarizing plate using the optical film of the present invention as one of the two protective films and the optical compensation film having optical anisotropy described later as the other is further provided with a contrast in a bright room of a liquid crystal display device. This is preferable because the viewing angle in the vertical and horizontal directions can be greatly widened.

(Optical compensation film)
The optical compensation film (retardation film) can improve viewing angle characteristics of a liquid crystal display screen.
As the optical compensation film, a known film can be used, but in terms of widening the viewing angle, an optically anisotropic layer made of a compound having a discotic structural unit described in JP-A-2001-100042 is disclosed. An optical compensation film characterized in that the angle formed by the discotic compound and the film surface changes in the depth direction of the optically anisotropic layer is preferable. That is, the orientation state of the compound having a discotic structural unit is preferably, for example, a hybrid orientation, a bent orientation, a twist orientation, a homogeneous orientation, a homeotropic orientation, or the like, and particularly preferably a hybrid orientation. It is preferable that the angle generally increases with an increase in the distance from the support surface side of the optical compensation film in the optically anisotropic layer when viewed in the entire layer.
When the optical compensation film is used as a protective film for the 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.

  Also, an embodiment in which the optically anisotropic layer further contains a cellulose ester, an embodiment in which an alignment layer is formed between the optically anisotropic layer and the transparent support of the optical compensation film, and the optically anisotropic layer An embodiment in which the transparent support of the optical compensation film has an optically negative uniaxial property and an optical axis in the normal direction of the surface of the transparent support, and an embodiment satisfying the following conditions are also preferable.

  20 ≦ {(nx + ny) / 2−nz} × d ≦ 400

In the equation, nx is a refractive index in the slow axis direction in the plane (maximum refractive index in the plane), ny is a refractive index in the direction perpendicular to the slow axis in the plane, and nz is a refractive index in the direction perpendicular to the plane. Rate. D is the thickness (nm) of the optically anisotropic layer.

(Image display device)
The optical film can be applied to an image display device such as a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), or a cathode ray tube display device (CRT). The antireflection film adheres the transparent support side of the antireflection film to the image display surface of the image display device.
The optical film and polarizing plate used in the present invention are twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically compensated bend cell (OCB), etc. This mode can be preferably used for a transmissive, reflective, or transflective liquid crystal display device. Especially for liquid crystal display devices in TN mode and IPS mode, Japanese Patent Laid-Open No. 2001-1000.
As described in JP-A-43 and the like, the viewing angle characteristic and the antireflection characteristic can be greatly improved by using a polarizing plate having the optical compensation film and the optical film as a protective film.
Further, by using in combination with a commercially available brightness enhancement film (a polarized light separation film having a polarization selection layer, such as D-BEF manufactured by Sumitomo 3M Co., Ltd.), in a transmissive or transflective liquid crystal display device, Furthermore, a display device with high visibility can be obtained.
Further, by combining with a λ / 4 plate, it can be used to reduce reflected light from the surface and the inside as a polarizing plate for reflective liquid crystal or a surface protective plate for organic EL display.

  In order to describe the present invention in detail, examples will be described below, but the present invention is not limited thereto.

(Synthesis of perfluoroolefin copolymer PF-1)

A stainless steel autoclave equipped with a stirrer was charged with 40 parts by mass of ethyl acetate, 14.7 parts by mass of hydroxyethyl vinyl ether, and 0.55 parts by mass of dilauroyl peroxide, and the system was deaerated and replaced with nitrogen gas. Further, 25 parts by mass 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 5.4 kg / cm ² (529 kPa). The reaction was continued for 8 hours while maintaining the temperature, and when the pressure reached 3.2 kg / cm ² (314 kPa), 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 parts by mass of the polymer product was obtained.
Next, 20 parts by mass of the polymer product was dissolved in 100 parts by mass of N, N-dimethylacetamide, and 11.4 parts by mass 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 and washed with water. The organic layer was extracted and concentrated, and the obtained polymer was reprecipitated with hexane to obtain 19 parts by mass of the perfluoroolefin copolymer PF-1. The resulting perfluoroolefin copolymer had a refractive index of 1.42.
The perfluoroolefin copolymer PF-1 was dissolved in methyl ethyl ketone to obtain a solution having a solid content concentration of 30%.

(Preparation of organosilane compound A solution)
In a 1,000 ml reaction vessel equipped with a thermometer, a nitrogen inlet tube and a dropping funnel, 187 g (0.80 mol) of acryloxyoxypropyltrimethoxysilane, 29.0 g (0.21 mol) of methyltrimethoxysilane, 320 g (10 mol) of methanol ) And KF 0.06g (0
. In addition, 17.0 g (0.94 mol) of water was slowly added dropwise at room temperature with stirring. After completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours, and then heated and stirred for 2 hours under methanol reflux. Then, 120 g of organosilane compound A solutions were obtained by depressurizingly distilling a low boiling point component and further filtering. As a result of GPC measurement of the substance thus obtained, the mass average molecular weight was 1500, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 30%.

Moreover, from the measurement result of 1H-NMR, the structure of the obtained substance has an average composition formula: (CH _{2
= COO-C 3 H 6)} 0.8 (CH 3) was a structure represented by _{0.2 SiO 0.86 (OCH 3) 1.28} . Furthermore, the condensation rate α as determined by ²⁹ Si-NMR was 0.59. From this analysis result, it was found that the silane coupling agent sol was mostly composed of a linear structure. From the gas chromatography analysis, the raw material acryloxypropyltrimethoxysilane had a residual rate of 5% or less.

  A reactor equipped with a stirrer and a reflux condenser, 120 parts by mass of methyl ethyl ketone, 100 parts by mass of 3-acryloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts by mass of diisopropoxyaluminum ethyl acetoacetate After adding a part and mixing, 30 mass parts of ion-exchange water was added, and it was made to react at 60 degreeC for 4 hours. The solution was cooled to room temperature to obtain a solution of organosilane compound 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, when analyzed by gas chromatography, the raw material 3-acryloxypropyltrimethoxysilane hardly remained.

(Preparation of resin particles (J-1))
A reactor equipped with a stirrer and a reflux condenser was charged with 600 parts by mass of water, and 0.7 parts by mass of polyvinyl alcohol and 2.7 parts by mass of sodium dodecylbenzenesulfonate were added thereto and dissolved. Next, a mixed liquid of 95.0 parts by mass of methyl methacrylate, 10.0 parts by mass of ethylene glycol dimethacrylate, and 2.0 parts by mass of benzoyl peroxide was added and stirred. This mixed solution was dispersed and homogenized at 9000 rpm for 15 minutes using a homogenizer. Next, stirring was continued at 75 ° C. for 4 hours while blowing nitrogen gas. Thereafter, it was dehydrated lightly by centrifugation, and the product was washed with water and dried. The obtained crosslinked methyl methacrylate resin particles (J-1) had an average particle size of 3.5 μm and a refractive index of 1.50.

For the resin particles J-1, the type and amount (unit: part by mass) of the binder main monomer and the type and amount of the crosslinkable monomer were changed to prepare the crosslinkable resin particles of the present invention and the resin particles of the comparative example. . The particle size of the particles was adjusted by changing the number of rotations of the homogenizer.
Tables 1 and 2 show the types and amounts of monomers and the characteristic values of the prepared particles. In Tables 1 and 2, the swelling rate indicates the swelling rate when a 30% by mass dispersion of toluene was prepared and the change in particle size disappeared over time. The calculation formula is as described in the text.

  Compressive strength is 25 ° C., 65% RH, test indenter: FLAT 20, test load: 19.6 (mN), load speed: 0.710982 (mN / sec) using a micro compression tester MCT-W201 manufactured by Shimadzu Corporation ), Displacement full scale: It was obtained by the above-described equation from a test of 10% displacement when conducted on a single particle under the condition of 5 (μm).

(Preparation of coating solution H-1 for light diffusion layer)
To 45.0 parts by mass of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (KAYARAD PET-30, manufactured by Nippon Kayaku Co., Ltd.), a polymerization initiator (
Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) 2.0 parts by mass, 0.75 parts by mass of fluorine-based surface conditioner (F-12), organosilane compound (KBM-5103, Shin-Etsu Chemical Co., Ltd.) 10.0 parts by mass, polymethyl methacrylate 20% by mass toluene solution (mass average molecular weight 120,000, Sigma-Aldrich Japan Co., Ltd.) 8.5 parts by mass, toluene 34.5 parts by mass were added and stirred. . After applying this solution, the refractive index of the coating film obtained by ultraviolet curing was 1.51. Furthermore, 25.5 parts by mass of a 30% toluene dispersion of resin particles J-1 dispersed at 10,000 rpm with a Polytron disperser was added and stirred. A light diffusion layer coating solution H-1 was prepared by filtration through a polypropylene filter having a pore size of 30 μm.

(Preparation of coating liquids H-2 to H-20 and RH-1 (comparative) to RH-5 (comparative) for light diffusion layer)
The light diffusion layer coating liquid H-2 is the same as the coating liquid H-1, except that the resin particles J-1 are changed to J-2 to J-23 with respect to the coating liquid H-1 for the light diffusion layer. ~ H-18, RH-1 (comparative) to RH-5 (comparative) were prepared. Furthermore, the binder component and the photopolymerization initiator were replaced with equal parts by mass of H-1 to prepare light diffusion layer coating liquids H-19 to H-20. The combinations of the compositions of the coating solutions are as shown in Table 3.

HP-7200: Dicyclopentadiene type epoxy resin (Dainippon Ink Chemical Co., Ltd.)
GT-401: Epolide GT-401, tetrafunctional epoxy compound (manufactured by Daicel Chemical Industries, Ltd.)
UVI-6990: Cationic polymerization initiator (manufactured by Ciba Specialty Chemicals)

(Preparation of coating solution L-1 for low refractive index layer)
In 15.0 parts by mass of a heat-crosslinkable fluorine-containing polymer having a refractive index of 1.42 (JN7228A, solid content concentration 6%, manufactured by JSR Corporation), a MEK dispersion of silica fine particles (MEK-ST, average particle size 15 nm, Solid content concentration 30%, manufactured by Nissan Chemical Industries, Ltd.) 0.6 parts by mass, M of silica fine particles
EK dispersion (MEK-ST-L, average particle size 45 nm, solid content concentration 30%, manufactured by Nissan Chemical Industries, Ltd.) 0.8 part by mass, organosilane compound A solution 0.4 part by mass, and methyl ethyl ketone 3 0.0 parts by mass and 0.6 parts by mass of cyclohexanone were added and stirred. The solution was filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating solution L-2 for a low refractive index layer. The refractive index of the coating film by this coating solution was 1.42.

(Preparation of MEK dispersion of hollow silica fine particles)
Hollow silica fine particle sol (Isopropyl alcohol silica sol, manufactured by Catalyst Chemical Industry Co., Ltd., average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20 mass%, silica particle refractive index 1.31, Preparation Example 4 of JP-A-2002-79616 500 parts by weight, 30 parts acryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.), and diisopropoxyaluminum ethyl acetate (trade names: Kerope EP-12, Hope Pharmaceutical ( 9 parts of ion-exchanged water was added after adding and mixing 1.5 parts). After reacting at 60 ° C. for 8 hours, the mixture was cooled to room temperature, and 1.8 parts of acetylacetone was added. While adding methyl ethyl ketone so that the content of silica was almost constant in 500 g of this dispersion, solvent substitution by vacuum distillation was performed at a pressure of 20 kPa. There was no generation of foreign matter in the dispersion, and the viscosity when the solid content concentration was adjusted to 20% by mass with methyl ethyl ketone was 5 mPa · s at 25 ° C. When the residual amount of isopropyl alcohol in the obtained dispersion A-1 was analyzed by gas chromatography, it was 1.5%.

(Preparation of coating liquid L-2 for low refractive index layer)
13.0 parts by mass of a heat-crosslinkable fluorine-containing polymer having a refractive index of 1.42 (JN7228A, solid content concentration 6%, manufactured by JSR Corporation) was added to the MEK dispersion of the above-described hollow silica fine particles (refractive index 1.31, 1.95 parts by mass (average particle size 60 nm, solid content concentration 20%), 0.6 parts by mass of the organosilane compound A solution, 4.35 parts by mass of methyl ethyl ketone, and 0.6 parts by mass of cyclohexanone were added and stirred. The mixture was filtered through a polypropylene filter having a pore diameter of 1 μm to prepare a coating solution L-3 for a low refractive index layer. The refractive index of the coating film by this coating solution was 1.40.

(Preparation of coating liquid L-3 for low refractive index layer)
In 10.5 parts by mass of the above-mentioned perfluoroolefin copolymer PF-1 (solid content concentration 30%), silica fine particle methyl ethyl ketone dispersion (MEK-ST-L, average particle size 45 nm, solid content concentration 30%, Nissan Chemical Industries, Ltd.) 4.5 parts by mass, polysiloxane compound having an acryloyl group (X-22-164C, Shin-Etsu Chemical Co., Ltd.) 0.15 parts by mass, photopolymerization initiator (Irgacure 907, Ciba Specialty Chemicals Co., Ltd.) 0.23 parts by mass, 2.0 parts by mass of the organosilane compound A solution, 81.2 parts by mass of methyl ethyl ketone, and 2.8 parts by mass of cyclohexanone were added and stirred. The solution was filtered through a polypropylene filter having a pore diameter of 1 μm to prepare a coating solution L-5 for a low refractive index layer. The refractive index of the coating film by this coating solution was 1.44.

[Example 1]
On a triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd., refractive index 1.48) having a thickness of 80 μm and a width of 1340 mm, a light diffusion layer coating solution (H-1 to H-20), comparison Coating liquids (RH-1 to RH-5) were applied by a slot die coating method with the film thickness adjusted by the coating amount under the condition of a conveyance speed of 25 m / min.
After dried for 150 seconds at 60 ° C., with a nitrogen purge (hereinafter oxygen concentration of 0.5%), using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co.), illuminance 400 mW / cm ^2, irradiation A film sample having a light diffusing layer was prepared by irradiating an ultraviolet ray having an amount of 250 mJ / cm ² to cure the coating layer.

On the light diffusion layer, the coating solution for low refractive index layer (L-1 to L-3) is adjusted by a slot die coating method so that the film thickness becomes 100 nm under the condition of a conveyance speed of 25 m / min. And applied.
Thereafter, the drying and curing conditions for L-1 to L-2 were as follows.
After drying at 120 ° C. for 150 seconds and further drying at 140 ° C. for 8 minutes, a 240 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) is used while purging with nitrogen (oxygen concentration 0.5% or less). Then, the coating layer was cured by irradiating 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 (outermost layer).
The drying and curing conditions for L-3 were as follows.
After drying at 90 ° C. for 30 seconds, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with a nitrogen purge (oxygen concentration of 0.5% or less), an illuminance of 600 mW / cm ² and an irradiation amount The coating layer was cured by irradiating 600 mJ / cm ² of ultraviolet rays to form a low refractive index layer (outermost layer).

  The coating combination and film thickness of the light diffusion layer and the low refractive index layer of the optical film sample according to the present invention were performed as described in Table 4.

  Film thickness: Indicates the film thickness of each coating layer after UV irradiation or after heat treatment.

(Evaluation of optical film)
About the obtained optical film sample, the following items were evaluated. The results are shown in Table 5.

(1) Antiglare property The entire surface of the produced optical film sample opposite to the light diffusion layer coating side was painted with black oil-based ink. Project the exposed fluorescent lamp (8000 cd / cm ² ) without the louver on the light diffusion layer coating side,
The degree of blur of the reflected image and the whiteness of the entire surface were evaluated according to the following criteria.
A: The outline of the fluorescent lamp is hardly understood.
○: The outline of the fluorescent lamp is slightly understood.
△: The fluorescent lamp appears whitish but the outline can be identified (within tolerance)
× (1): The fluorescent lamp looks clear and the reflected light is dazzling.
× (2): The outline of the fluorescent lamp is not known at all, but the entire surface is whitish.
(2) Evaluation of average reflectance Using a spectrophotometer (manufactured by JASCO Corporation; V-550), in the wavelength region of 380 to 780 nm, using a integrating sphere, the spectral reflectance at an incident angle of 5 ° is calculated. It was measured. In the evaluation of the spectral reflectance, an average reflectance of 450 to 650 nm was used.

(3) Pencil Hardness Pencil hardness was evaluated according to JIS K 5400, except for the following condition changes, on the light diffusion layer coating side. The antireflection film was conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, and then subjected to a hardness test at a load of 500 g using a 3H-8H test pencil specified in JIS S 6006. The test was performed from a soft hardness pencil, and the test was repeated 5 times under the same conditions. Among the pencil hardnesses where the number of scratches that were not visible was 3 or more, the highest pencil hardness was taken as the hardness of the sample.

(4) Steel wool resistance On the light diffusion layer coating side, a rubbing test with steel wool was performed using a rubbing tester. Steel wool (grade No. 0000, manufactured by Nippon Steel Wool Co., Ltd.) is used as the scraping material, braking distance (one way) 13 cm, rubbing speed 13 cm / sec, load 4.9 N / cm ² , contact area 1 cm × 1 cm, rubbing The number of times was 10 round trips. The scratches on the surface of the outermost layer were visually observed and evaluated in the following four stages.
◎: Even if you look carefully, no scratches are visible.
○: Slight scratches are visible when carefully viewed.
Δ: Weak scratches are visible.
X: A noticeable scratch can be seen at first glance.

(5) Curling degree The optical film sample was cut into a size of 20 cm × 20 cm, and placed on a horizontal desk in an environment of 25 ° C. and 60% RH with the surfaces where the four corners were raised facing upward. After 24 hours, the lifting distance from the desk surface at each of the four corners was measured with a ruler, and the average of the four corners was taken. The average values were classified and evaluated according to the following criteria.
◎: Less than 5 mm ○: Less than 5-10 mm ○ △: Less than 10-20 mm Δ: Less than 20-40 mm ×: 40 mm or more (6) Centerline average roughness (Ra)
According to JIS-B0601, the centerline average roughness Ra of the film was measured at a cutoff value of 0.25 mm and a magnification of 10,000 times. As a measuring device, Kosaka Laboratory Co., Ltd., universal surface shape measuring device MODEL SE-3F was used.
(7) Image clarity The transmitted image clarity was measured with an optical comb width of 0.5 mm according to JIS K7105.

From the results in Table 5, it can be seen that both the antiglare property and the pencil hardness are excellent when the particle size of the resin particles according to the present invention is in the particle size range defined by the present invention. (Samples 101 and 126, 132 to 136 with respect to Samples 130 and 131) When the particle size deviates from the range defined in the present invention, the larger particle size is too anti-glare and has an increase in whiteness. If it is too small, the antiglare effect is weakened.
It can also be seen that when the compressive strength is 2 kgf / mm ² or more, the pencil hardness is excellent. (Samples 101-126 and 132-136 with respect to Samples 127-129)
It was first demonstrated by the present invention that the coating film hardness can be increased by using particles having high compressive strength.

[Example 2]
(Evaluation of image display device)
The optical films of the samples 101 to 126 and 132 to 136 of Example 1 are transferred to an image display device (transmission type, reflection type or transflective type liquid crystal display device in TN, STN, IPS, VA, or OCB mode, and The plasma display panel (PDP), the electroluminescence display (ELD), and the cathode ray tube display (CRT) were mounted on the display surface. The image display device using the optical film of the present invention was excellent in antireflection properties, surface hardness, scratch resistance, and antifouling properties.
Furthermore, there is no recess with a cut surface area of 100 μm ² or more, and the pixel size is 100 p.
There was no glare failure in the image display device at pi (100 pixels / inch: 100 pixels per inch length).

[Example 3]
(Preparation of protective film for polarizing plate)
A saponification solution was prepared by keeping a 1.5N sodium hydroxide aqueous solution at 50 ° C. Further, a 0.01N dilute sulfuric acid aqueous solution was prepared.
In the antireflection films of Samples 101 to 126 and 132 to 136 of Example 1, the surface of the transparent support opposite to the side having the low refractive index layer (outermost layer) was saponified using the saponification solution. .
The sodium hydroxide aqueous solution on the surface of the saponified transparent support is thoroughly washed with water, then washed with the above diluted sulfuric acid aqueous solution, and further, the diluted sulfuric acid aqueous solution is thoroughly washed with water and sufficiently dried at 100 ° C. I let you.
When the contact angle of the surface of the saponified transparent support on the side opposite to the side having the low refractive index layer (outermost layer) of the optical film was evaluated, it was 40 ° or less. Thus, the protective film for polarizing plates was produced.

(Preparation of polarizing plate)
An antireflection film of the present invention (protective film for polarizing plate) is prepared by using a PVA (PVA-117H manufactured by Kuraray Co., Ltd.) 3% aqueous solution as an adhesive on one surface of a deflection film described in JP-A-2002-86554. The saponified triacetyl cellulose surface of the film) was bonded together. Further, a triacetyl cellulose film (Fuji Photo Film Co., Ltd., Fujitac, retardation value 3.0 nm) saponified in the same manner as above was bonded to the other surface of the polarizing film using the same adhesive. . Thus, the polarizing plate of this invention was produced.

(Evaluation of image display device)
The TN, STN, IPS, VA, OCB mode transmission type, reflection type, or semi-transmission type liquid crystal display device equipped with the polarizing plate of the present invention thus produced has antireflection properties, dustproof properties, Excellent scratch resistance and antifouling properties.
Similar results were obtained with polarizing plates produced in the same manner as described above using various known deflection films.

[Example 4]
(Preparation of polarizing plate)
The surface of the optical compensation film (Wide View Film SA 12B, manufactured by Fuji Photo Film Co., Ltd.) opposite to the side having the optically anisotropic layer was saponified under the same conditions as in Example 3. In the same manner as in Example 3, the saponified triacetyl cellulose surface of the optical film (protective film for polarizing plate) produced in Example 3 was bonded to one surface of the polarizing film. Further, the triacetyl cellulose surface of the saponified optical compensation film was bonded to the other surface of the polarizing film in the same manner.

(Evaluation of image display device)
The TN, STN, IPS, VA, OCB mode transmission type, reflection type, or semi-transmission type liquid crystal display device equipped with the polarizing plate of the present invention thus manufactured does not use an optical compensation film. Compared with a liquid crystal display device equipped with a polarizing plate, it had excellent contrast in a bright room, wide viewing angles in the vertical and horizontal directions, and was excellent in antireflection, surface hardness, scratch resistance, and antifouling properties.
In particular, due to the light scattering effect of the resin particles, the viewing angle in the downward direction is remarkably widened, and the yellowness in the horizontal direction is improved.
Similar results were obtained with polarizing plates produced in the same manner as described above using various known deflection films.

[Example 5]
(Evaluation of image display device)
When the antireflection films of Samples 101 to 126 and 132 to 136 of Example 1 were mounted on an organic EL display device, they were excellent in antireflection properties, dust resistance, scratch resistance, and antifouling properties.
In addition, a polarizing plate protective film prepared in Example 4 on one surface of the polarizing film and a polarizing plate having a λ / 4 plate on the other surface were prepared in the same manner as in Example 4. When the above polarizing plate was mounted on an organic EL display device, reflection of light from the glass surface on which the polarizing plate was attached was also cut, and a display device with extremely high visibility was obtained.

Claims (10)

The transparent support has a light diffusion layer containing at least one kind of resin particles having a particle diameter of 0.5 μm to 5 μm and a binder matrix, and the compressive strength of the resin particles is 2 kgf / mm ² to 10
An optical film characterized by being kgf / mm ² .   2. The optical film according to claim 1, wherein the center line average roughness (Ra) of the outermost surface on the light diffusion layer coating side is 0.12 μm or more.   3. The optical film according to claim 1, wherein the swelling rate after the resin particles are immersed in the dispersion solvent is 20% by volume or less.   The resin particles are crosslinked with a bifunctional or higher monomer, and the content of the crosslinkable monomer is 15% by mass or more based on the total monomers for forming the resin particles. The optical film in any one.   The optical film according to claim 1, wherein a difference in refractive index between the resin particles and the binder matrix is 0 to 0.20.   6. The optical film according to claim 1, wherein the resin particles are resin particles obtained by polymerizing a (meth) acrylic acid ester monomer.   The light diffusion layer contains 20 to 100% by mass of an epoxy resin having two or more epoxy groups in one molecule as a binder with respect to the total binder. The optical film described in 1.   The optical film in any one of Claims 1-7 is an antireflection film, The antireflection film characterized by the above-mentioned.   A polarizing plate, wherein the antireflection film according to claim 8 is used for at least one of two protective films of a polarizing film.   An optical display according to any one of claims 1 to 7, an antireflection film according to claim 8, or a polarizing plate according to claim 9 is disposed on an image display surface. .