JP2007069471A - Optical film, antireflection film, polarizing plate, and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film which is improved in dispersibility of fine inorganic oxide particles without spoiling performance including reflectance and scratch resistance, prevents the deterioration of a film surface state by the aggregation of the inorganic oxide particles, and is good in production efficiency. <P>SOLUTION: In the optical film, an optical function layer is formed on a transparent support by the application of an optical function layer forming coating solution. The coating solution contains the fine silanized inorganic oxide particles. The surface of the inorganic oxide particle has at least 1.4 silyl groups per 1 nm<SP>2</SP>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device such as a liquid crystal display, a plasma display, and a CRT, and more particularly to an antireflection film excellent in antireflection and visibility, and a polarizing plate using the same.

  Optical films, especially antireflection films, are generally used in cathode ray tube display (CRT), plasma display (PDP), electroluminescent display (ELD), and liquid crystal display (LCD) display devices to reduce contrast due to reflection of external light. In order to prevent reflection of images and images, it is arranged on the outermost surface of the display in order to reduce reflectivity using the principle of optical interference.

  Such an antireflection film has a low refractive index layer having an appropriate thickness on the outermost surface, and optionally a high refractive index layer, a medium refractive index layer, a hard coat layer, an antiglare layer, and an antistatic layer. It can be produced by forming a layer, a light diffusion layer, or the like. In order to realize a low reflectance, a material having a refractive index as low as possible is desired for the low refractive index layer. Further, since the antireflection film is used on the outermost surface of the display, high scratch resistance is required. In order to realize high scratch resistance in a thin film having a thickness of around 100 nm, the strength of the coating itself is necessary.

  In order to lower the refractive index of the material, there is a means of using a fluorine-containing polymer as a binder resin, but the film strength is impaired and the scratch resistance is lowered, and it is difficult to achieve both low refractive index and high scratch resistance. Met.

  Therefore, there is a means for improving the scratch resistance by increasing the hardness of the coating surface by containing an appropriate amount of inorganic oxide fine particles in the low refractive index layer made of a fluorine-containing polymer. This means was effective in improving the low reflectance and scratch resistance, but there was a problem that the inorganic oxide fine particles were aggregated in the low refractive index layer and the film surface was deteriorated.

  In addition to further reducing reflectivity and image reflectivity, as well as providing hard coat properties and dustproof properties, a high refractive index layer and a medium refractive index layer are appropriately provided between the low refractive index layer and the support. In some cases, an antiglare layer, a hard coat layer, an antistatic layer or the like is formed. In general, a method of containing inorganic oxide fine particles in a layer is used as means for adjusting the refractive index of the layer, forming irregularities on the layer surface, increasing the hardness of the layer, and imparting conductivity. However, as described above, there is a problem that the inorganic oxide fine particles aggregate in the layer and the film surface state deteriorates.

  In general, it is important that inorganic oxide fine particles are stably dispersed in an organic solvent so as not to cause aggregation in the organic solvent. Specifically, it is important to control hydrophilicity / hydrophobicity and steric hindrance on the surface of the inorganic oxide fine particles, and it is known that the inorganic oxide fine particles are surface-treated using alkoxysilane. For example, Non-Patent Document 1 describes a method of dispersing inorganic particles in an organic solvent using a silane coupling agent. Further, Patent Documents 1 to 3 describe that the scratch resistance and the strength of the layer are improved by surface-treating inorganic fine particles in advance. Further, Patent Document 4 also describes the effect on storage stability against the aggregation of inorganic fine particles in the coating solution. However, in the drying process in which the optical functional layer forming coating liquid containing the inorganic oxide fine particles is applied to form the optical functional layer, the organic solvent volatilizes and the concentration of the inorganic oxide fine particles increases, thereby promoting aggregation. For this reason, the level of stability of particle dispersion in the formed optical functional layer is still insufficient.

On the other hand, as means for improving the mechanical dispersibility, there is a means for forming a functional fine particle-containing layer by applying ultrasonic treatment to a liquid in which fine particles are dispersed, and applying and drying the dispersion (see Patent Document 5). The dispersion before coating is surely effective in improving dispersibility. However, as described above, the organic solvent volatilizes during the drying process and the concentration of the inorganic oxide fine particles increases, so that there is almost no effect in terms of improving the fine particle dispersibility in the formed layer.
Japanese Unexamined Patent Publication No. 2000-9908 (page 3) JP 2001-310423 (page 3) JP 2001-100013 A (page 3) JP 2001-272502 A (page 3) JP 2001-327917 (pages 4-5) "Pigment Dispersion Technology Surface Treatment, Dispersant Usage and Dispersibility Evaluation" (Technical Information Association, 1999 edition)

  The present inventors apply a coating liquid for forming an optical functional layer containing inorganic oxide fine particles on a transparent support, and the inorganic oxide fine particles aggregate in the drying process to form the optical functional layer. I learned that there was a problem that the surface condition worsened.

The object of the present invention is to improve the dispersibility of the inorganic oxide fine particles without impairing the performance such as reflectance and scratch resistance, and to prevent the deterioration of the film surface due to the aggregation of the inorganic oxide fine particles. The object is to provide a film (particularly an antireflection film).
Another object of the present invention is to provide a polarizing plate and a display device comprising the optical film (particularly, an antireflection film).

  As a result of intensive studies, the present inventor has found that the above object of the present invention is achieved by an optical film and an antireflection film having the following constitution.

(1) In an optical film having at least one hard coat layer on a transparent support and further having an optical functional layer containing inorganic fine particles as an upper layer, the surface energy of the hard coat layer is 45 mJ / m ² or less. The inorganic fine particles contained in the optical functional layer contain 1.1 or more silyl groups per 1 nm ^{2 of} the surface area.
(2) The optical film, wherein the hard coat layer according to (1) contains a fluorine-based leveling agent or a silicone-based leveling agent.
(3) The optical film, wherein the hard coat layer according to the above (1) or (2) contains a polymer that does not substantially contain a fluorine atom and a silicon atom.
(4) The antireflection film as described in any one of (1) to (3) above, wherein the inorganic fine particles are hollow inorganic oxide particles.
(5) The antireflection film as described in any one of (1) to (4) above, wherein the optical functional layer is a low refractive index layer.
(6) In the polarizing plate formed by sandwiching a polarizer between two protective films, one protective film of the polarizing plate is the optical film according to any one of the above (1) to (3) or the above (4) to (5) A polarizing plate, which is the antireflection film according to any one of (5).
(7) A display device comprising the polarizing plate according to (6).
(8) A display device comprising the optical film according to any one of (1) to (3) or the antireflection film according to any one of (4) to (5).

  The optical film of the present invention, particularly the antireflection film, does not impair the performance such as reflectance and scratch resistance, and the dispersibility of the inorganic oxide fine particles in the coating solution for forming the optical functional layer and in the optical functional layer. As a result of the improvement, the film surface state is not deteriorated due to the aggregation of the inorganic oxide fine particles, and the production efficiency is good. The polarizing plate using the optical film and the antireflection film of the present invention has the above-described excellent performance. Furthermore, the display device including the optical film and the antireflection film of the present invention has very high visibility because there is little reflection of external light and reflection of the background.

  Hereinafter, the present invention will be described in detail. In the present specification, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”. .

In the optical film of the present invention, the inorganic oxide fine particles of the optical functional layer contain 1.1 or more silyl groups per 1 nm ^{2 of} the surface area.

  The transparent support, which is the support for the optical film, is composed of a single layer or a plurality of layers, and may be formed by drum casting or band casting, or may be formed by coating on the transparent support. The optical film may have a plurality of optical functional layers.

The coating liquid for forming an optical functional layer contains fine particles as appropriate for the purpose of imparting hard coat properties and scratch resistance, adjusting the refractive index, imparting conductivity, and imparting surface irregularities, and has high strength and refractive index. Inorganic oxide fine particles are preferred from the standpoints of selection range, conductivity, and colorlessness. It is preferable that the inorganic oxide fine particles do not aggregate in the coating solution for forming the optical functional layer and are stably dispersed. Further, after coating the coating solution, the fine particle concentration increases in the drying process due to volatilization of the organic solvent. It is important that the film does not aggregate even when the optical film is manufactured, without impairing the film surface shape of the optical film and producing an optical film with good production efficiency.
In order for inorganic oxide fine particles to be stably dispersed in an organic solvent, it is necessary to make the surface of the fine particles hydrophobic. As a method of hydrophobizing treatment, there is a method of esterifying hydroxyl groups on the surface of fine particles by heating in the presence of excess alcohol, but this reaction requires a high temperature, or when a high boiling alcohol is used. Excessive alcohol removal is difficult. Further, the hydrophobic fine particles obtained by this esterification method have a drawback that the hydrophobicity is easily lost due to hydrolysis of the alkoxy group.
On the other hand, there is a method of treating the surface of the inorganic oxide fine particles with a silylating agent as another method, which is preferable because it can be treated under mild conditions when compared with the esterification method.
In order to prevent agglomeration even when the concentration of fine particles is increased during the drying process after coating a coating solution containing fine particles, 1.1 or more silyl per 1 nm ² of surface area of the silylated inorganic oxide fine particles It is necessary that the groups are bonded, and preferably 1.4 or more, and more preferably 1.6 or more. If the number is less than 1.1, fine particles aggregate in the drying process, the reflectance increases, and the antireflection ability deteriorates.
On the other hand, there is no upper limit on the number of silyl groups bonded per 1 nm ² of surface area of the fine particles due to the characteristics of the optical film, but a large amount of silylating agent is required to bond more than 3.0 silyl groups, and 100 ° C. Since the treatment is required at the above high temperature, it is not industrially efficient.

The amount of silyl groups bonded to the inorganic oxide fine particles can be known by a method of measuring the carbon content by elemental analysis of the silylated inorganic oxide fine particles. The number of silyl groups per unit surface area can be calculated by dividing by the specific surface area of the fine particles determined by the BET method.
If the inorganic oxide fine particles are already dispersed in an organic solvent or the like, the inorganic oxide fine particles can be isolated by a centrifugal method or the like. It is possible to know the bonding amount of the group. When the composition contains a plurality of types of inorganic oxide fine particles and cannot be isolated individually, the average value obtained by simultaneously measuring a plurality of mixed fine particles is defined as the silyl group bond amount.
When the inorganic oxide fine particles are contained in the optical film, the inorganic oxide fine particles can be isolated by decomposing the binder component or the support with nitric acid, diluting with water, and centrifuging. . The amount of silyl group bonded can be determined by measuring the carbon content as described above.

(Silylation treatment)
The silylation treatment of the inorganic oxide fine particles can be performed by allowing the silica gel represented by the general formula (I) to act on the surface of the inorganic oxide fine particles.
Formula (I)
R ¹⁰ _m Si (X) _4-m
(In the formula, R ¹⁰ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. X represents a hydroxyl group or a hydrolyzable group. M represents an integer of 1 to 3.)

[Silylating agent]
The silylating agent of the present invention will be described in detail.
In the general formula (I), R ¹⁰ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, hexyl, t-butyl, sec-butyl, hexyl, decyl, hexadecyl and the like. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Examples of the aryl group include phenyl and naphthyl, and a phenyl group is preferable.

X represents a hydroxyl group or a hydrolyzable group. Examples of the hydrolyzable group include an alkoxy group (an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group and an ethoxy group), a halogen atom (for example, Cl, Br, I and the like), and R ^2. COO (R ² is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples include CH ₃ COO, C ₂ H ₅ COO, etc.), preferably an alkoxy group, particularly preferably a methoxy group. Or it is an ethoxy group.
m represents an integer of 1 to 3. When R ¹⁰ or X there are a plurality, a plurality of R ¹⁰ or X groups may be different, even the same, respectively. m is preferably 1 or 2, particularly preferably 1.

The substituent contained in R ¹⁰ is not particularly limited, but is a halogen atom (fluorine atom, chlorine atom, bromine atom, etc.), hydroxyl group, mercapto group, carboxyl group, epoxy group, alkyl group (methyl, ethyl, i-propyl). , Propyl, t-butyl, etc.), aryl groups (phenyl, naphthyl, etc.), aromatic heterocyclic groups (furyl, pyrazolyl, pyridyl, etc.), alkoxy groups (methoxy, ethoxy, i-propoxy, hexyloxy, etc.), aryloxy (Phenoxy, etc.), alkylthio groups (methylthio, ethylthio, etc.), arylthio groups (phenylthio, etc.), alkenyl groups (vinyl, 1-propenyl, etc.), acyloxy groups (acetoxy, acryloyloxy, methacryloyloxy, etc.), alkoxycarbonyl groups (methoxy) Carbonyl, ethoxycarbonyl, etc.), aryl Oxycarbonyl groups (such as phenoxycarbonyl), carbamoyl groups (such as carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-methyl-N-octylcarbamoyl), acylamino groups (acetylamino, benzoylamino, acrylicamino, methacrylic) Amino) and the like, and these substituents may be further substituted. In the present specification, even if a hydrogen atom is replaced by a single atom, it is treated as a substituent for convenience.
When there are a plurality of R ¹⁰ , at least one is preferably a substituted alkyl group or a substituted aryl group, and among them, an organosilane compound having a vinyl polymerizable substituent represented by the following general formula (II) is preferable. .

Formula (II)

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

L represents a divalent linking chain. For example, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group having a linking group (for example, ether, ester, amide, etc.) therein, a substituted or unsubstituted alkylene group having a linking group inside An unsubstituted arylene group is exemplified, and a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, and an alkylene group having a linking group therein are preferred, an unsubstituted alkylene group, an unsubstituted arylene group, and an inside An alkylene group having an ether or ester linking group is more preferred, an unsubstituted alkylene group, and an alkylene group having an ether or ester linking group inside is particularly preferred. Examples of the substituent include a halogen, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, and an aryl group, and these substituents may be further substituted.
In the general formula (II), l (small L) and m represent a mole fraction, and l is l = 10.
It represents a number that satisfies the mathematical formula 0-m, and m represents a number from 0 to 50. As for m, the number of 0-40 is more preferable, and the number of 0-30 is especially preferable. When m is more than 50, solid content is generated, the liquid becomes cloudy, the pot life is deteriorated, the molecular weight is difficult to control (increase in molecular weight), or the content of the polymerizable group is small. This is not preferable because it is difficult to improve the performance (for example, the scratch resistance of the antireflection film) when the treatment is performed.

The weight average molecular weight of the organosilane compound having a vinyl polymerizable substituent represented by the general formula (II) is preferably 450 to 20,000, more preferably 500 to 10,000, still more preferably 550 to 5,000, and 600 to 3,000. Is more preferable.
Here, the weight average molecular weight is expressed in terms of polystyrene by GTH analyzer using a column of TSKgel GMHxL, TSKgel G4000HxL, TSKgel G2000HxL (both trade names manufactured by Tosoh Corporation) and solvent THF and differential refractometer detection. Molecular weight.

R ^{2 to} R ⁴ represent a halogen atom, a hydroxyl group, an unsubstituted alkoxy group, or an unsubstituted alkyl group. R ^{2 to} R ⁴ 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 particularly preferably a hydroxyl group or a methoxy group.
R ⁵ represents a hydrogen atom or an alkyl group. R ⁵ is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, particularly preferably a hydrogen atom or a methyl group.

R ⁶ 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, Most preferably, it is a C1-C6 thing. Specific examples of the alkyl group include methyl, ethyl, propyl, isopropyl, hexyl, decyl, hexadecyl and the like. Examples of the aryl group include phenyl and naphthyl, and a phenyl group is preferable. The substituent contained in R ⁶ is not particularly limited, but a halogen atom (fluorine, chlorine, bromine, etc.), hydroxyl group, mercapto group, carboxyl group, epoxy group, alkyl group (methyl, ethyl, i-propyl, propyl, t-butyl etc.), aryl groups (phenyl, naphthyl etc.), aromatic heterocyclic groups (furyl, pyrazolyl, pyridyl etc.), alkoxy groups (methoxy, ethoxy, i-propoxy, hexyloxy etc.), aryloxy (phenoxy etc.) ), Alkylthio groups (methylthio, ethylthio, etc.), arylthio groups (phenylthio, etc.), alkenyl groups (vinyl, 1-propenyl, etc.), acyloxy groups (acetoxy, acryloyloxy, methacryloyloxy, etc.), alkoxycarbonyl groups (methoxycarbonyl, ethoxy) Carbonyl, etc.), aryloxy Carbonyl groups (phenoxycarbonyl, etc.), carbamoyl groups (carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-methyl-N-octylcarbamoyl, etc.), acylamino groups (acetylamino, benzoylamino, acrylicamino, methacrylamino) Etc.), and these substituents may be further substituted. A polymerizable functional group other than the vinyl polymerizable group such as an epoxy group or an isocyanate group is also preferable as a substituent. As the substituent for R ⁶ , a hydroxyl group or an unsubstituted alkyl group is more preferred, a hydroxyl group or an alkyl group having 1 to 3 carbon atoms is more preferred, and a hydroxyl group or a methyl group is particularly preferred.

  The compound of general formula (II) is synthesized using one or more silane compounds as starting materials. Although the specific example of the silane compound used as the starting material of general formula (II) below is shown, it is not limited.

Among these, it is particularly preferable to use (M-1), (M-2), (M-25), (M-48), and (M-49) as starting materials.
In the present invention, the amount of the silylating agent represented by the general formula (I) is not particularly limited, but is preferably 0.1% by mass to 150% by mass, more preferably 0.8%, per inorganic oxide fine particle. It is 3 mass%-100 mass%, Most preferably, it is 1 mass%-75 mass%. In terms of the surface area of the inorganic oxide fine particles, 0.1 to 10 mmol / 100 m ^{2 of} fine particle surface area is preferable, more preferably 0.3 to 5 mmol / 100 m ^{2 of} fine particle surface area, and most preferably 0.5 to 3 mmol / 100 m ^{2 of} fine particle surface area. It is. When the amount of the silylating agent used is in the above range, a sufficient stabilizing effect of the dispersion can be obtained, and the film strength is also great when forming a coating film.

[Inorganic oxide fine particles]
Next, inorganic oxide fine particles that can be used in the present invention will be described.
The inorganic oxide fine particles are at least one selected from the group consisting of silicon, aluminum, zirconium, titanium, zinc, germanium, indium, tin, antimony and cerium from the viewpoint of the colorlessness of the cured film of the resulting curable composition. Elemental oxide particles are preferred.

  Examples of these inorganic oxide fine particles include particles such as silica, alumina, zirconia, titanium oxide, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, and cerium oxide. be able to. Of these, particles of silica, alumina, zirconia and antimony oxide are preferred from the viewpoint of high hardness. These can be used alone or in combination of two or more. Furthermore, the inorganic oxide fine particles are preferably used as an organic solvent dispersion. When used as an organic solvent dispersion, the dispersion medium is preferably an organic solvent from the viewpoint of compatibility with other components and dispersibility. Examples of such an organic solvent include alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, butyl acetate, ethyl lactate, and γ-butyrolactone. , Esters such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate; ethers such as ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; aromatic hydrocarbons such as benzene, toluene and xylene; dimethylformamide, dimethylacetamide, Examples thereof include amides such as N-methylpyrrolidone. Of these, methanol, isopropanol, butanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, toluene and xylene are preferred.

  The number average particle diameter of the inorganic oxide fine particles is 1 nm to 5000 nm, but when contained in the low refractive index layer, 3 nm to 200 nm is preferable, and 5 nm to 100 nm is more preferable. Moreover, when containing in a hard-coat layer, 3 nm-3000 nm are preferable, and 5 nm-2000 nm are more preferable. When the number average particle diameter exceeds 5000 nm, the transparency of the cured product tends to decrease, or the surface state of the coating tends to deteriorate. Various surfactants and amines may be added to improve the dispersibility of the particles.

Examples of products that are commercially available as silicon oxide fine particle dispersions (for example, silica particles) include colloidal silica, methanol silica sol manufactured by Nissan Chemical Industries, Ltd., MA-ST-MS, IPA-ST, IPA- ST-MS, IPA-ST-L, IPA-ST-ZL, IPA-ST-UP, EG-ST, NPC-ST-30, MEK-ST, MEK-ST-L, MIBK-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, ST-OL, etc. ) Hollow silica CS60-IPA and the like.
As the powder silica, KE-P150, KE-P250 manufactured by Nippon Shokubai Co., Ltd., Aerosil 130 manufactured by Nippon Aerosil Co., Ltd., Aerosil 300, Aerosil 380, Aerosil TT600, Aerosil OX50, Sildex H31 manufactured by Asahi Glass Co., Ltd. , H32, H51, H52, H121, H122, Nippon Silica Industry Co., Ltd. E220A, E220, Fuji Silysia Co., Ltd. SYLYSIA470, Nippon Sheet Glass Co., Ltd. SG flakes, etc. can be mentioned.

  Further, as the aqueous dispersion of alumina fine particles, alumina sol-100, -200, -520 manufactured by Nissan Chemical Industries, Ltd .; as the isopropanol dispersion of alumina, AS-150I manufactured by Sumitomo Osaka Cement Co., Ltd .; toluene of alumina As a dispersion, AS-150T manufactured by Sumitomo Osaka Cement Co., Ltd. As a toluene dispersion of zirconia, HXU-110JC manufactured by Sumitomo Osaka Cement Co., Ltd .; As a water dispersion of zinc antimonate powder, Nissan Chemical Industries ( CELNAX Co., Ltd .; Nanotech made by Cai Kasei Co., Ltd. for powders and solvent dispersions of alumina, titanium oxide, tin oxide, indium oxide, zinc oxide, etc .; Ishihara Sangyo for water dispersion sol of antimony-doped tin oxide SN-100D manufactured by Mitsubishi Materials Corporation, manufactured by Mitsubishi Materials Corporation, oxidized The helium aqueous dispersion, mention may be made of Taki Chemical Co., Ltd. Nidoraru like.

The inorganic oxide fine particles have a spherical shape, a hollow shape, a porous shape, a rod shape, a plate shape, a fiber shape, or an indefinite shape, and preferably a spherical shape or a hollow shape. The hollow silica particles will be described later. The specific surface area of the inorganic oxide fine particles (by the BET specific surface area measurement method using nitrogen) is preferably 10 to 1000 m ² / g, and more preferably 100 to 500 m ² / g. These inorganic oxide fine particles can be obtained by dispersing powder in a dry state in an organic solvent. For example, a dispersion of fine oxide particles known in the art as a solvent dispersion sol of the above oxide is directly used. Can be used.

[Sililation solvent]
The silylation treatment can be performed without a solvent or in a solvent. When a solvent is used, the concentration of the silylating agent can be appropriately determined. As the solvent, an organic solvent is preferably used in order to uniformly mix the components. For example, alcohols, aromatic hydrocarbons, ethers, ketones, esters and the like are preferable.
The solvent preferably dissolves the silylating agent. In addition, it is preferable in the process that an organic solvent is used as a coating solution or a part of the coating solution, and those that do not impair the solubility or dispersibility when mixed with other materials such as a fluorine-containing polymer are preferable.

Among these, examples of the alcohols include monohydric alcohols and dihydric alcohols. Among these, monohydric alcohols are preferably saturated aliphatic alcohols having 1 to 8 carbon atoms. Specific examples of these alcohols include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol. Examples thereof include monobutyl ether and ethylene glycol monoethyl ether acetate.
Specific examples of aromatic hydrocarbons include benzene, toluene and xylene, specific examples of ethers include tetrahydrofuran and dioxane, and specific examples of ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Specific examples of esters such as diisobutylketone and the like include ethyl acetate, propyl acetate, butyl acetate, and propylene carbonate.

  These organic solvents can be used alone or in combination of two or more. The concentration of the silylating agent relative to the solvent in the treatment is not particularly limited, but is usually in the range of 0.1% by mass to 70% by mass, and preferably in the range of 1% by mass to 50% by mass.

  In the present invention, it is preferable to disperse the inorganic oxide fine particles with an alcohol solvent and then perform a dispersibility improvement treatment, and subsequently replace the dispersion solvent with an aromatic hydrocarbon solvent or a ketone solvent. Substitution with a ketone solvent is preferable from the viewpoint of improving the affinity with the binder used at the time of coating and the stability of the dispersion itself.

  An optical functional layer can be formed by applying the coating composition for forming an optical functional layer in combination with a binder composition using the inorganic oxide fine particles whose surface is silylated on the surface of the present invention described above. . In particular, it is suitable for forming a low refractive index layer of an antireflection film.

[Silylation reaction]
The silylation reaction proceeds at room temperature after the addition of the silylating agent, but can be accelerated by heating. In normal temperature, it is preferable to make it react for 1 day or more. In the case of heating, the reaction time is usually several hours. The heating is preferably performed at a temperature lower than the boiling point of the reaction medium, and more preferably performed at 40 to 100 ° C.

(Layer structure of optical film)
Examples of the optical functional layer in the present invention include an antireflection layer and an intermediate layer in which the refractive index is controlled. Specifically, the antireflection layer has a refractive index and a film thickness so that the reflectance is reduced by optical interference. A controlled low refractive index layer may be mentioned. The optical functional layer in the present invention is most preferably a low refractive index layer.
The optical film of the present invention, particularly the antireflection film, has a hard coat layer to be described later on a transparent base material (support), and has a refractive index and a film thickness so that the reflectance is reduced by optical interference thereon. The layers are stacked in consideration of the number of layers, the layer order, and the like. In order to reduce the reflectance of the low-reflection laminate, the antireflection layer is formed by combining a high refractive index layer having a higher refractive index than that of the base material and a low refractive index layer having a lower refractive index than that of the base material. It is preferable. Examples of configurations include two layers of a high refractive index layer / low refractive index layer from the base material side, and three layers having different refractive indices, a medium refractive index layer (having a higher refractive index than the base material or the hard coat layer). , A layer having a lower refractive index than a high refractive index layer) / a high refractive index layer / a low refractive index layer, and the like. Especially, it is preferable to apply | coat in order of a middle refractive index layer / high refractive index layer / low refractive index layer on the base material which has a hard-coat layer from durability, an optical characteristic, cost, productivity, etc.

The hard coat layer may be an anti-glare hard coat layer (also referred to as “anti-glare layer”) having an uneven surface.
The optical functional layer may be any of a low refractive index layer, a medium refractive index layer, and a high refractive index layer. Furthermore, there may be a different layer between the (antiglare) hard coat layer and the optical functional layer, but the (antiglare) hard coat layer and the optical functional layer are in direct contact with each other from the viewpoint of productivity. preferable.

Examples of preferred layer configurations of the low reflection laminate of the present invention are shown below.
In the following layer configuration, the optical functional layer may be any of a low refractive index layer, a medium refractive index layer, and a high refractive index layer.
Base film / (anti-glare) hard coat layer / low refractive index layer Base film / hard coat layer / (anti-glare) hard coat layer / low refractive index layer Base film / (anti-glare) hard coat layer / High refractive index layer / Low refractive index layer Base film / (Anti-glare) Hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer Base film / Antistatic layer / (Anti-glare) Hard coat layer / low refractive index layer Antistatic layer / base film / (antiglare) hard coat layer / low refractive index layer base film / antistatic layer / (antiglare) hard coat layer / medium refractive index layer / High refractive index layer / Low refractive index layer Antistatic layer / Base film / (Anti-glare) hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer

As long as the reflectance can be reduced by optical interference, it is not limited to these layer configurations. The hard coat layer may be an antiglare hard coat layer imparted with an antiglare function. The hard coat layer may be a light diffusive hard coat layer having no antiglare function and having a light diffusion function. Further, the high refractive index layer and the middle refractive index layer may be provided with an antiglare function, a hard coat function, and a light diffusion function. The antistatic layer is preferably a layer containing conductive polymer particles or metal oxide fine particles (for example, SnO ₂ , ITO), and can be provided by coating or atmospheric pressure plasma treatment.

[Material for low refractive index layer]
The low refractive index layer is preferably formed by a cured film of a copolymer having a repeating unit derived from a fluorine-containing vinyl monomer and a repeating unit having a (meth) acryloyl group in the side chain as essential constituent components. The copolymer-derived component preferably occupies 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 80% by mass or more. From the viewpoint of achieving both low refractive index and film hardness, a curing agent such as polyfunctional (meth) acrylate is also preferably used in an addition amount within a range that does not impair the compatibility.

The refractive index of the low refractive index layer is preferably 1.20 to 1.46, more preferably 1.25 to 1.46, and particularly preferably 1.30 to 1.46.
The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 100 nm. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less. The specific strength of the low refractive index layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test under a 500 g load.
In order to improve the antifouling performance of the optical film, it is preferable that the contact angle of the surface with respect to water is 90 ° or more. More preferably, it is 95 ° or more, and particularly preferably 100 ° or more.

The copolymer preferably used for the low refractive index layer of the present invention will be described below.
Examples of the fluorine-containing vinyl monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, etc.), (meth) acrylic acid moieties or fully fluorinated alkyl ester derivatives (for example, biscoat 6FM (trade name) , Osaka Organic Chemical Co., Ltd.) and R-2020 (trade name, manufactured by Daikin Co., Ltd.), fully or partially fluorinated vinyl ethers, and the like. Preferred are perfluoroolefins, refractive index, solubility, and transparency. From the viewpoint of availability, hexafluoropropylene is particularly preferable. Increasing the composition ratio of these fluorinated vinyl monomers can lower the refractive index but lowers the film strength. In the present invention, 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%. This is a case of mass%.

The copolymer of the present invention preferably has a repeating unit having a (meth) acryloyl group in the side chain as an essential component. If the composition ratio of these (meth) acryloyl group-containing repeating units is increased, the film strength is improved, but the refractive index is also increased. Generally, the (meth) acryloyl group-containing repeating unit preferably accounts for 5 to 90% by mass, more preferably 30 to 70% by mass, although it varies depending on the type of repeating unit derived from the fluorine-containing vinyl monomer. It is particularly preferred to account for ~ 60% by weight.
In the copolymer useful for the present invention, in addition to the repeating unit derived from the above-mentioned fluorine-containing vinyl monomer and the repeating unit having a (meth) acryloyl group in the side chain, it contributes to adhesion to the substrate and Tg of the polymer (film hardness). And other vinyl monomers can be copolymerized as appropriate from various viewpoints such as solubility in a solvent, transparency, slipperiness, dust resistance and antifouling properties. A plurality of these vinyl monomers may be combined depending on the purpose, and are preferably introduced in the range of 0 to 65 mol% in the copolymer in total, and in the range of 0 to 40 mol%. More preferably, it is particularly preferably in the range of 0 to 30 mol%.

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

In the present invention, inorganic particles that can be preferably used for the low refractive index layer of the antireflection film will be described.
The coating amount of the inorganic fine particles is preferably ^{1mg / m 2 ~100mg / m 2} , more preferably ^{5mg / m 2 ~80mg / m 2} , more preferably from ^{10mg / m 2 ~60mg / m 2} . If the amount is too small, the effect of improving the scratch resistance is reduced. If the amount is too large, fine irregularities are formed on the surface of the low refractive index layer, and the appearance such as black tightening and the integrated reflectance are deteriorated. Since the inorganic fine particles are contained in the low refractive index layer, it is desirable that the inorganic fine particles have a low refractive index.
Specifically, inorganic oxide particles or hollow inorganic oxide particles that have been subjected to dispersibility improving treatment by the silylation treatment described above, and those having a low refractive index are preferably used. For example, fine particles of silica or hollow silica can be mentioned. The average particle diameter of the silica fine particles is preferably 30% to 150% of the thickness of the low refractive index layer, more preferably 35% to 80%, and still more preferably 40% to 60%. That is, when the thickness of the low refractive index layer is 100 nm, the particle diameter of the silica fine particles is preferably 30 nm to 150 nm, more preferably 35 nm to 80 nm, and still more preferably 40 nm to 60 nm.

If the particle size of the silica fine particles is too small, the effect of improving the scratch resistance is reduced. If it is too large, fine irregularities are formed on the surface of the low refractive index layer, and the appearance such as black tightening and the integrated reflectance are deteriorated. The silica fine particles may be either crystalline or amorphous, and may be monodispersed particles or aggregated particles as long as a predetermined particle size is satisfied. The shape is most preferably a spherical diameter, but there is no problem even if the shape is indefinite.
In order to lower the refractive index of the low refractive index layer, it is preferable to use hollow silica fine particles. The hollow silica fine particles have a refractive index of 1.17 to 1.40, more preferably 1.17 to 1.35, and still more preferably 1.17 to 1.30. The refractive index here represents the refractive index of the entire particle, and does not represent the refractive index of only the outer shell silica forming the hollow silica particles. At this time, when the radius of the cavity in the particle is a and the radius of the particle outer shell is b, the porosity x is calculated by the following formula (I).

(Formula ^{I) x = (4πa 3/} 3) / (4πb 3/3) × 100

The porosity x is preferably 10 to 60%, more preferably 20 to 60%, and most preferably 30 to 60%. If the hollow silica particles are made to have a lower refractive index and a higher porosity, the thickness of the outer shell becomes thinner and the strength of the particles becomes weaker. Rate particles do not hold.
The refractive index of these hollow silica particles was measured with an Abbe refractometer (manufactured by Atago Co., Ltd.).
Moreover, the refractive index of this layer can be reduced by containing hollow particles in the low refractive index layer. When the hollow particles are used, the refractive index of the layer is preferably 1.20 or more and 1.46 or less, more preferably 1.25 or more and 1.41 or less, and most preferably 1.30 or more and 1.39 or less. It is.

Further, at least one kind of silica fine particles having an average particle size of less than 25% of the thickness of the low refractive index layer (referred to as “small size particle size silica particles”) is used as silica fine particles having the above particle size (“large size particles”). It is preferably used in combination with “silica fine particles having a diameter”. Since the fine silica particles having a small particle size can exist in the gaps between the fine silica particles having a large particle size, they can contribute as a retaining agent for the fine silica particles having a large particle size.
When the low refractive index layer is 100 nm, the average particle size of the silica fine particles having a small size is preferably from 1 nm to 20 nm, more preferably from 5 nm to 15 nm, and particularly preferably from 10 nm to 15 nm. Use of such silica fine particles is preferable in terms of raw material costs and a retaining agent effect.

  In the present invention, it is preferable to reduce the surface free energy on the surface of the antireflection film from the viewpoint of improving the antifouling property. Specifically, it is preferable to use a fluorine-containing compound or a compound having a polysiloxane structure for the low refractive index layer. Examples of additives having a polysiloxane structure include reactive group-containing polysiloxanes (for example, KF-100T, X-22-169AS, KF-102, X-22-3701IE, X-22-164B, X-22-5002, X-22-173B, X-22-174D, X-22-167B, X-22-161AS (above product names, manufactured by Shin-Etsu Chemical Co., Ltd.), AK-5, AK-30, AK-32 (above product names) , Manufactured by Toa Gosei Co., Ltd.), Silaplane FM0725, Silaplane FM0721 (named above, trade name, manufactured by Chisso Corporation), etc.) are also preferably added. In addition, silicone compounds described in Tables 2 and 3 of JP-A No. 2003-112383 can also be preferably used. These polysiloxanes are preferably added in the range of 0.1 to 10% by mass of the total solid content of the low refractive index layer, particularly preferably 1 to 5% by mass.

[Material for hard coat layer]
The optical film of the present invention has a hard coat layer. The hard coat layer can be formed of a binder, matte particles for imparting an antiglare function and a light diffusion function, and inorganic fine particles for increasing the refractive index, preventing crosslinking shrinkage, and increasing the strength.
It is preferable to use a compound having an ethylenically unsaturated group as the binder component in terms of film strength, coating solution stability, coating film productivity, and the like. The main film-forming binder refers to one that accounts for 10% by mass or more of the film-forming components excluding inorganic fine particles. Preferably, they are 20 mass% or more and 100 mass% or less, More preferably, they are 30 mass% or more and 95% or less.
A polymer having a saturated hydrocarbon chain or a polyether chain as a main chain is preferable, and a polymer having a saturated hydrocarbon chain as a main chain is more preferable. As the binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure, a (co) polymer of monomers having two or more ethylenically unsaturated groups is preferable.
In order to obtain a high refractive index, the monomer structure preferably contains an aromatic ring or at least one atom selected from halogen atoms other than fluorine, sulfur atoms, phosphorus atoms, and nitrogen atoms.
Examples of the monomer having two or more ethylenically unsaturated groups include esters of polyhydric alcohol and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetra ( (Meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, di Pentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polymer Acrylate), vinylbenzene and its derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (eg, divinylsulfone), acrylamide (eg, , Methylenebisacrylamide) and methacrylamide. Two or more of these monomers may be used in combination. In the present specification, “(meth) acrylate” represents “acrylate or methacrylate”.

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

Polymerization of these monomers having an ethylenically unsaturated group can be carried out by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator.
Photo radical polymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds And fluoroamine compounds and aromatic sulfoniums. Examples of acetophenones include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone and 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone is included. Examples of benzoins include benzoin benzene sulfonate, benzoin toluene sulfonate, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether. Examples of the benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone. Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
Various examples are described in the latest UV curing technology (P.159, issuer; Kazuhiro Takashiro, publisher; Technical Information Association, Inc., published in 1991), which is useful for the present invention.
Preferable examples of commercially available photocleavable photoradical polymerization initiators include Irgacure (651, 184, 907) manufactured by Nippon Ciba-Geigy Co., Ltd.
It is preferable to use a photoinitiator in the range of 0.1-15 mass parts with respect to 100 mass parts of polyfunctional monomers, More preferably, it is the range of 1-10 mass parts.

In addition to the photopolymerization initiator, a photosensitizer may be used. Specific examples of the photosensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, Michler's ketone and thioxanthone.
As the thermal radical initiator, organic or inorganic peroxides, organic azo, diazo compounds, and the like can be used.
Specifically, benzoyl peroxide, halogen benzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide, butyl hydroperoxide as organic peroxides, hydrogen peroxide, peroxides as inorganic peroxides. Ammonium sulfate, potassium persulfate, etc., 2-azo-bis-isobutyronitrile, 2-azo-bis-propionitrile, 2-azo-bis-cyclohexanedinitrile, etc. as diazo compounds, diazoaminobenzene, p -Nitrobenzenediazonium etc. can be mentioned.

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

  For the purpose of imparting antiglare properties, the hard coat layer contains matte particles having an average particle size of 0.1 to 5.0 μm, preferably 1.5 to 3.5 μm, such as inorganic compound particles or resin particles. be able to. If the difference in refractive index between the matte particles and the binder is too large, the film becomes cloudy, and if it is too small, a sufficient light diffusion effect cannot be obtained, so 0.02 to 0.20 is preferable, and 0.04 to Particularly preferred is 0.10. Similarly to the refractive index, the addition amount of the matting particles with respect to the binder is too large, the film becomes cloudy, and if it is too small, a sufficient light diffusion effect cannot be obtained. A percentage is particularly preferred.

As specific examples of the mat particles, inorganic particles such as silica particles and TiO ₂ particles; resin particles such as acrylic particles, crosslinked acrylic particles, polystyrene particles, crosslinked styrene particles, melamine resin particles, and benzoguanamine resin particles are preferable. Can be mentioned. Of these, crosslinked styrene particles, crosslinked acrylic particles, and silica particles are preferred.
As the shape of the mat particle, either a true sphere or an indefinite shape can be used.

Two or more different kinds of mat particles may be used in combination. When two or more kinds of mat particles are used, the difference in refractive index is preferably 0.02 or more and 0.10 or less in order to effectively exert the refractive index control by mixing the two, and 0.03 or more. Is particularly preferably 0.07 or less. Further, it is possible to impart an antiglare property with mat particles having a larger particle size and to impart another optical characteristic with mat particles having a smaller particle size. For example, when an optical film is attached to a high-definition display of 133 ppi or more, it is required that there is no problem in optical performance called glare. Glare originates from the fact that the pixels are enlarged or reduced due to unevenness existing on the film surface (contributing to anti-glare properties) and lose uniformity of brightness, but with a particle size smaller than that of mat particles that provide anti-glare properties. It can be greatly improved by using mat particles having a different refractive index from the binder.
Furthermore, the particle size distribution of the mat particles is most preferably monodisperse, and the particle sizes of the particles are preferably closer to each other. For example, when particles having a particle size of 20% or more than the average particle size are defined as coarse particles, the proportion of coarse particles is preferably 1% or less of the total number of particles, more preferably 0.1%. Or less, more preferably 0.01% or less. Matt particles having such a particle size distribution are obtained by classification after a normal synthesis reaction, and a matting agent having a more preferable distribution can be obtained by increasing the number of classifications or increasing the degree of classification.
The mat particles are contained in the hard coat layer so that the amount of the mat particles in the formed hard coat layer is preferably 10 to 1000 mg / m ² , more preferably 100 to 700 mg / m ² .
The particle size distribution of the mat particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution.

The hard coat layer has at least one selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony, in addition to the above mat particles, in order to increase the refractive index of the layer and to reduce cure shrinkage. It is preferable to contain inorganic fine particles made of one kind of metal oxide and having an average particle size of 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less.
In order to increase the difference in refractive index from the mat particles, it is also preferable to use a silicon oxide in order to keep the refractive index of the hard coat layer using the high refractive index mat particles low. The preferred particle size is the same as that of the aforementioned inorganic fine particles.
Specific examples of the inorganic fine particles used for the hard coat layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and SiO ₂ . TiO ₂ and ZrO ₂ are particularly preferable from the viewpoint of increasing the refractive index. The surface of the inorganic fine particles is preferably treated with a silylating agent, and a surface treating agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.
The amount of these inorganic fine particles added is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and particularly preferably 30 to 70% by mass with respect to the total mass of the hard coat layer.
Such a filler does not scatter because the particle size is sufficiently smaller than the wavelength of light, and a dispersion in which the filler is dispersed in a binder polymer behaves as an optically uniform substance.

The bulk refractive index of the mixture of the binder and inorganic fine particles of the hard coat layer of the present invention is preferably 1.48 to 2.00, more preferably 1.50 to 1.80. In order to make the refractive index within the above range, the type and amount ratio of the binder and the inorganic fine particles may be appropriately selected. How to select can be easily known experimentally in advance.
The optical film of the present invention thus formed has a haze value of 3 to 70%, preferably 4 to 60%, and an average reflectance of 450 nm to 650 nm is 3.0% or less, preferably 2.5% or less.
When the optical film of the present invention has a haze value and an average reflectance in the above ranges, good antiglare properties and antireflection properties can be obtained without causing deterioration of the transmitted image.

The hard coat layer preferably uses various leveling agents for the purpose of preventing unevenness. Specifically, as the leveling agent, a fluorine-based leveling agent or a silicone-based leveling agent is preferable, and in particular, a fluorine-based leveling agent is preferable because of its high unevenness preventing ability.
In the present invention, the leveling agent is preferably an oligomer or polymer rather than a low molecular weight compound because of its high unevenness preventing ability.
When a leveling agent is added to the hard coat layer, the leveling agent is quickly unevenly distributed on the surface of the applied liquid film, and the leveling agent is unevenly distributed on the surface even after the hard coat layer is dried. The surface energy is reduced by the leveling agent.
Therefore, it is preferable that the surface energy of the hard coat layer is low from the viewpoint of preventing unevenness of the hard coat layer.

The surface energy of hard coat layer (γs ^v : unit, mJ / m ² ) is experimental on antiglare hard coat layer with reference to DKOwens: J.Appl.Polym.Sci., 13,1941 (1969) is represented by the sum of pure water between H ₂ O and methylene iodide CH ₂ respective contact angle theta _{H2 O} of I _2, where theta following simultaneous equations from _CH2I2 (1) (2) from the obtained gamma] s ^d and gamma] s ^h obtained in This is an energy conversion value of the surface tension of the antiglare hard coat layer defined by the value γs ^v (= γs ^d + γs ^h ). (The mN / m unit is mJ / m ² unit.) Before the sample is measured, it is necessary to adjust the humidity for a certain period of time under a predetermined temperature and humidity condition. The temperature at this time is preferably in the range of 20 ° C. to 27 ° C., the humidity is preferably in the range of 50 RH% to 65 RH%, and the humidity conditioning time is preferably 2 hours or more.

(1) 1 + cos θH ₂ O = 2√γs ^d (√γH ₂ Od / γH ₂ Ov) + 2√γs ^h (√γH ₂ Oh / γH ₂ Ov)
(2) 1 + cos θCH ₂ I ₂ = 2√γs ^d (√γCH ₂ I ₂ d / γCH ₂ I ₂ v) + 2√γs ^h (√γCH ₂ I ₂ h / γCH ₂ I ₂ v)
Here, γ _H2O ^d = 21.8 °, γ _H2O ^h = 51.0 °, γ _H2O ^v = 72.8 °, γ _CH2I2 ^d = 49.5 °, γ _CH2I2 ^h = 1.3 °, and γ _CH2I2 ^v = 50.8 °.

The surface energy of the hard coat layer is in the range of 45 mJ / m ² or less, preferably in the range of 20~45mJ / m ^2, and most preferred range of 25~40mJ / m ^2.
By setting the surface energy of the hard coat layer to 45 mJ / m ² or less, it is possible to obtain an effect that uneven coating of the hard coat layer hardly occurs.
However, since an upper layer such as a low refractive index layer is further coated on the hard coat layer, the leveling agent is preferably eluted into the upper layer, and the hard coat layer is coated with a solvent (for example, methyl ethyl ketone) in the hard coat layer upper layer coating solution. It is preferable that the surface energy of the hard coat layer after the immersion is rather high, and it is preferable that the surface energy is 35 to 70 mJ / m ² .

  Hereinafter, in the present invention, a preferred fluorine-based leveling agent as a leveling agent for the hard coat layer will be described. The silicone leveling agent will be described later.

As the fluorine-based leveling agent, a polymer having a fluoroaliphatic group is preferable, and a polymer of a repeating unit (polymerization unit) corresponding to the monomer (i) below, or a repeating unit corresponding to the monomer (i) below. An acrylic resin, a methacrylic resin, and a copolymer with a vinyl monomer copolymerizable therewith are useful, including (polymerized unit) and a repeating unit (polymerized unit) corresponding to the monomer (ii) below. Examples of such monomers include Polymer Handbook 2nd ed. , J .; Brandrup, Wiley Interscience (1975) Chapter 2, Pages 1-483 can be used.
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.

  (I) Fluoroaliphatic group-containing monomer represented by the following general formula 1

  General formula 1

In the general formula 1, R ¹ represents a hydrogen atom, a halogen atom or a methyl group, preferably a hydrogen atom or a methyl group. X represents an oxygen atom, a sulfur atom or —N (R ¹² ) —, more preferably an oxygen atom or —N (R ¹² ) —, and still more preferably an oxygen atom. R ¹² represents a hydrogen atom or an optionally substituted alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and further preferably a hydrogen atom or a methyl group. R _f represents —CF ₃ or —CF ₂ H.
M in the general formula 1 represents an integer of 1 to 6, more preferably 1 to 3, and still more preferably 1.
N in the general formula 1 represents an integer of 1 to 11, more preferably 1 to 9, and still more preferably 1 to 6. R _f is preferably —CF ₂ H.
In addition, two or more kinds of polymer units derived from the fluoroaliphatic group-containing monomer represented by the general formula 1 may be contained in the fluorine-based polymer as a constituent component.

  (Ii) Monomer represented by the following general formula 2 copolymerizable with the above (i)

  General formula 2

In the above general formula 2, R ¹³ represents a hydrogen atom, a halogen atom or a methyl group, more preferably a hydrogen atom or a methyl group. Y represents an oxygen atom, a sulfur atom or —N (R ¹⁵ ) —, more preferably an oxygen atom or —N (R ¹⁵ ) —, and still more preferably an oxygen atom. R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and further preferably a hydrogen atom or a methyl group.
R ¹⁴ is a linear, branched or cyclic alkyl group having 1 to 60 carbon atoms which may have a substituent, or an aromatic group which may have a substituent (for example, a phenyl group or a naphthyl group). ). The alkyl group may include a poly (alkyleneoxy) group. A linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, an alkyl group containing a poly (alkyleneoxy) group having 5 to 40 carbon atoms, or an aromatic group having 6 to 18 carbon atoms is more preferable. Alkyl groups including 8 linear, branched, or cyclic alkyl groups and poly (alkyleneoxy) groups having 5 to 30 carbon atoms are highly preferred. The poly (alkyleneoxy) group will be described below.

Poly (alkyleneoxy) groups can be represented by (OR) x, R is 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 — or —CH (CH ₃ ) CH (CH ₃ ) — is preferred. x represents 2-30, 2-20 are preferable and 4-15 are more preferable.

  The oxyalkylene units in the poly (oxyalkylene) group may be the same as in poly (oxypropylene), or two or more different oxyalkylenes may be randomly distributed. It may be a linear or branched oxypropylene or oxyethylene unit, or a linear or branched oxypropylene unit block and an oxyethylene unit block.

The poly (oxyalkylene) chain may also include those linked by one or more chain bonds (for example, —CONH—Ph—NHCO—, —S—, etc .: Ph represents a phenylene group). If the chain bond has a valence of 3 or more, this provides a means for obtaining branched oxyalkylene units. When this copolymer is used in the present invention, the molecular weight of the poly (oxyalkylene) group is suitably from 250 to 3,000.
Poly (oxyalkylene) acrylates and methacrylates are commercially available hydroxypoly (oxyalkylene) materials such as trade name “Pluronic” (manufactured by Asahi Denka Kogyo Co., Ltd.), Adeka polyether (manufactured by Asahi Denka Kogyo Co., Ltd.). ) "Carbowax (Glyco Products)", "Triton" [Toriton (Rohm and Haas) and PEG (Daiichi Kogyo Seiyaku Co., Ltd.) Can be produced by reacting them with acrylic acid, methacrylic acid, acrylic chloride, methacrylic chloride or acrylic anhydride, etc. Separately, poly (oxyalkylene) diacrylate produced by a known method is used. You can also.

  The amount of the fluoroaliphatic group-containing monomer represented by the general formula 1 used in the production of the fluoropolymer used in the present invention is 10% by mass or more based on the total amount of the monomer of the fluoropolymer, Preferably it is 50 mass% or more, More preferably, it is 70-100 mass%, More preferably, it is the range of 80-100 mass%.

Hereinafter, examples of specific structures of the fluorine-based polymer according to the present invention are shown, but the present invention is not limited thereto.
In addition, the number in a formula shows the molar ratio of each monomer component. Mw represents a mass average molecular weight.

  The amount of the polymerization unit of the fluoroaliphatic group-containing monomer constituting the fluoropolymer used in the present invention is preferably more than 10% by mass, more preferably 50 to 100% by mass, and unevenness of the hard coat layer If the viewpoint of preventing the above is emphasized, it is most preferably 75 to 100% by mass, and when the low refractive index layer is applied on the hard coat layer, it is most preferably 50 to 75% by mass. (Described in all polymer units constituting the fluoropolymer)

Next, the silicone leveling agent will be described.
Examples of the silicone-based leveling agent include polydimethylsiloxane having various substituents such as oligomers such as ethylene glycol and propylene glycol, and the side chain and the terminal of the main chain are modified. KF-96 manufactured by Shin-Etsu Chemical Co., Ltd. X-22-945.

In addition, a nonionic surfactant having a hydrophobic group composed of dimethylpolysiloxane and a hydrophilic group composed of polyoxyalkylene can also be preferably used.
Specific examples of these nonionic surfactants include, for example, Nippon Unicar Co., Ltd., silicone surfactants SILWET L-77, L-720, L-7001, L-7002, L-7604, Y-7006, FZ-2101, FZ-2104, FZ-2105, FZ-2110, FZ-2118, FZ-2120, FZ-2122, FZ-2123, FZ-2130, FZ-2154, FZ-2161, FZ-2162, FZ- 2163, FZ-2164, FZ-2166, FZ-2191, and SUPERSILWET SS-2801, SS-2802, SS-2803, SS-2804, SS-2805, and the like.
In addition, as a preferable structure of the nonionic surfactant in which the hydrophobic group is composed of dimethylpolysiloxane and the hydrophilic group is composed of polyoxyalkylene, a dimethylpolysiloxane structure portion and a polyoxyalkylene chain are alternately and repeatedly bonded. A linear block copolymer is preferred, and JP-A-6-49486 can be referred to.
Specific examples thereof include, for example, silicone surfactants ABN SILWET FZ-2203, FZ-2207, FZ-2208 and the like manufactured by Nippon Unicar Co., Ltd.

  The amount of the fluorine-containing leveling agent and silicone leveling agent added to the coating solution is preferably 0.001% by mass to 1.0% by mass, more preferably 0.01% by mass to 0.2% by mass. It is.

-Thickener for hard coat layer A thickener may be used for the hard coat layer in order to adjust the viscosity of the coating solution.
The term “thickener” as used herein means that the viscosity of the liquid is increased by adding it, and is preferably 0.05 to 50 cP as the magnitude of increase in the viscosity of the coating liquid by adding it. More preferably, it is 0.10-20 cP, Most preferably, it is 0.10-10 cP.
It is preferable that the polymer used as the thickener does not substantially contain a fluorine atom and / or a silicon atom. Here, “substantially” means that the content of fluorine atoms and / or silicon atoms in the mass of the polymer is 0.1% by mass or less, preferably 0.01% by mass or less.

Such a thickener is preferably a high molecular polymer, and specific examples include, but are not limited to, the following.
Polyacrylic acid ester Polymethacrylic acid ester Polyvinyl acetate Polyvinyl propionate Polyvinyl butyrate Polyvinyl butyral Polyvinyl formal Polyvinyl acetal Polyvinyl propanal Polyvinyl hexanal Polyvinyl pyrrolidone Cellulose acetate Cellulose propionate Cellulose acetate butyrate Among these, especially polymethacrylic acid ester ( Specifically, polymethyl methacrylate, polyethyl methacrylate), polyvinyl acetate, polyvinyl propionate, cellulose propionate, and cellulose acetate butyrate are preferable.
Further, those having a mass average molecular weight of 100,000 to 1,000,000 are preferable.

  Other known viscosity modifiers such as smectite, tetrasilica mica, bentonite, silica, montmorillonite and sodium polyacrylate, JP-A-10-219136, ethyl cellulose, polyacrylic acid, and organic clay described in JP-A-8-325491. Or a thixotropic agent can be used.

[Support]
A plastic film is preferably used as the transparent support of the optical film of the present invention. Examples of the polymer forming the plastic film include cellulose esters (eg, triacetyl cellulose, diacetyl cellulose, typically TAC-TD80U, TD80UF, etc. manufactured by Fuji Photo Film), polyamides, polycarbonates, polyesters (eg, polyethylene terephthalate, polyethylene). Naphthalate), polystyrene, polyolefin, norbornene resin (Arton: trade name, manufactured by JSR), amorphous polyolefin (ZEONEX: trade name, manufactured by Nippon Zeon), and the like. Of these, triacetyl cellulose, polyethylene terephthalate, and polyethylene naphthalate are preferable, and triacetyl cellulose is particularly preferable. In addition, the cellulose acylate film substantially free of halogenated hydrocarbons such as dichloromethane and the process for producing the same are disclosed in the JIII Journal of Technical Disclosure (Publication No. 2001-1745, published on March 15, 2001; The cellulose acylate described herein can also be preferably used in the present invention.

(Method for producing optical film)
[Method for forming optical functional layer]
The optical film of the present invention can be formed by the following method, but is not limited to this method.
First, a coating solution containing components for forming each layer is prepared. The coating solution is applied onto a transparent support by dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating or extrusion coating (see US Pat. No. 2,681,294). Heat and dry. Among these coating methods, it is preferable to apply the gravure coating method because a coating solution with a small coating amount such as each layer of the antireflection film can be applied with high film thickness uniformity. Among the gravure coating methods, the micro gravure method has a high film thickness uniformity and is more preferable.
In addition, a coating solution with a small coating amount can be applied with high film thickness uniformity even by using a die coating method. Further, since the die coating method is a pre-measuring method, film thickness control is relatively easy, and the solvent in the coating part Is preferred because of less transpiration. Two or more layers may be applied simultaneously. The method of simultaneous application is described in US Pat. Nos. 2,761,791, 2,941,898, 3,508,947, and 3,526,528 and Yuji Harasaki, Coating Engineering, page 253, Asakura Shoten (1973).

[Saponification]
When the optical film of the present invention is used in a liquid crystal display device, it is disposed on the outermost surface of the display by providing an adhesive layer on one side. When the transparent support is triacetyl cellulose, triacetyl cellulose is used as a protective film for protecting the polarizing layer of the polarizing plate. Therefore, it is preferable in terms of cost to use the optical film of the present invention as it is for the protective film.
When the optical film of the present invention is disposed on the outermost surface of a display by providing an adhesive layer on one side or used as it is as a protective film for a polarizing plate, the optical film on the transparent support is sufficient for adhesion. It is preferable to perform a saponification treatment after forming an outermost layer mainly composed of a fluorine-containing polymer. The saponification treatment is performed by a known method, for example, by immersing the film in an alkali solution for an appropriate time. After being immersed in the alkaline solution, it is preferable to sufficiently wash with water or neutralize the alkaline component by dipping in a dilute acid so that the alkaline component does not remain in the film.
By saponification treatment, the surface of the transparent support opposite to the side having the outermost layer is hydrophilized.
The hydrophilized surface is particularly effective for improving the adhesion with a polarizing film containing polyvinyl alcohol as a main component. In addition, the hydrophilic surface makes it difficult for dust in the air to adhere to it, making it difficult for dust to enter between the polarizing film and the optical film when bonded to the polarizing film, and is effective in preventing point defects caused by dust. It is.
The saponification treatment is preferably carried out so that the contact angle of water on the surface of the transparent support opposite to the side having the outermost layer is 40 ° or less. More preferably, it is 30 ° or less, particularly preferably 20 ° or less.

Specific means for the alkali saponification treatment can be selected from the following two means (1) and (2). Hereinafter, an antireflection film will be described as an example. (1) is superior in that it can be processed in the same process as a general-purpose triacetyl cellulose film, but since the saponification treatment is performed up to the antireflection layer surface, the surface is alkali-hydrolyzed and the film deteriorates. If it remains, it becomes a problem that it becomes dirty. In that case, although it becomes a special process, (2) is excellent.
(1) After the antireflection layer is formed on the transparent support, the back surface of the film is saponified by immersing it in an alkaline solution at least once.
(2) Before or after forming the antireflection layer on the transparent support, an alkaline solution is applied to the surface of the optical film opposite to the surface on which the optical film is formed, and is heated, washed and / or neutralized. Thus, only the back surface of the film is saponified.

[Polarizer]
The polarizing plate is mainly composed of two protective films that sandwich the polarizing film from both sides. The optical film of the present invention is preferably used for at least one of the two protective films sandwiching the polarizing film from both sides. The manufacturing cost of a polarizing plate can be reduced because the optical film of the present invention also serves as a protective film. In addition, by using the optical film of the present invention, particularly the antireflection film, as the outermost layer, reflection of external light and the like can be prevented, and a polarizing plate having excellent scratch resistance and antifouling properties can be obtained.
As the polarizing film, a known polarizing film or a polarizing film cut out from a long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction may be used. A long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction is produced by the following method.
That is, a polarizing film stretched by applying tension while holding both ends of a continuously supplied polymer film by a holding means, stretched at least 1.1 to 20.0 times in the film width direction, The progress of the film is such that the difference between the moving speeds in the longitudinal direction of the holding device is within 3%, and the angle formed by the film moving direction at the exit of the step of holding both ends of the film and the substantial stretching direction of the film is inclined by 20 to 70 °. The film can be produced by a stretching method in which the direction is bent while holding both ends of the film. In particular, those inclined by 45 ° are preferably used from the viewpoint of productivity.
The method for stretching the polymer film is described in detail in paragraphs 0020 to 0030 of JP-A-2002-86554.

  When the optical film of the present invention is used as one side of a surface protective film of a polarizing film, it is twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically. It can be preferably used for a transmissive, reflective, or transflective liquid crystal display device in a mode such as a compensated bend cell (OCB).

The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). (2) In addition to (2) Liquid crystal cell (SID97, Digest of tech. Papers (Preliminary Collection) 28 (1997) 845 in which the VA mode is converted into a multi-domain (MVA mode) for viewing angle expansion ), (3) A liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Preliminary collections 58-59 of the Japan Liquid Crystal Society) (1998)) and (4) SURVAVAL mode liquid crystal cells (announced at LCD International 98).
For a VA mode liquid crystal cell, a polarizing plate prepared by combining a triacetyl cellulose film stretched biaxially with the optical film of the present invention is preferably used. As for the method for producing a biaxially stretched triacetyl cellulose film, for example, the methods described in JP-A Nos. 2001-249223 and 2003-170492 are preferably used.

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

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

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

  Examples of the present invention will be described below, but the present invention is not limited thereto. In the following examples, “part” means “part by mass”.

Silylation of inorganic oxide fine particles
(Preparation of dispersion P-1)
Silica fine particle sol (isopropyl alcohol silica sol, IPA-ST-L manufactured by Nissan Chemical Industries, Ltd., average particle diameter 45 nm, silica concentration 30%), 500 parts, trimethylmethoxysilane 27.2 parts (2.9 mmol / silica sol A silica surface area of 100 m ² ) was added and mixed with stirring. Thereafter, the mixture was reacted at 60 ° C. for 2 hours to obtain a silylated silica sol. While adding methyl ethyl ketone to the silylation-treated silica sol, the solvent was replaced by vacuum distillation at a pressure of 100 Torr so that the total liquid amount was constant. The amount of residual isopropanol in the obtained dispersion was 1.0% or less as analyzed by gas chromatography. The solid content concentration of this solvent-substituted silylation-treated silica sol was adjusted to 30% with methyl ethyl ketone to obtain dispersion P-1.
This dispersion P-1 was dried under reduced pressure at 50 ° C., pulverized, further dried at 110 ° C. for 1 hour, and subjected to elemental analysis. The carbon content was 0.62% by weight. It corresponds to 1.72 per 1 nm ^{2 of} surface area.

In the dispersion P-1, except that the silylation treatment agent represented by the general formula (I), the silylation treatment time, and the addition amount of the silylation treatment agent were changed as shown in Table 1, P- A dispersion of 2 to P-6 was prepared. The number of silyl groups per 1 nm ^{2 of the} fine particle surface area was evaluated by the same method as described above for the obtained dispersion.

(Adjustment of dispersion Q-1)
In 500 parts of silica fine particle sol (isopropyl alcohol silica sol, IPA-ST-ZL, average particle diameter 100 nm, silica concentration 30%, manufactured by Nissan Chemical Industries, Ltd.), 6.1 parts of trimethylmethoxysilane (1.4 mmol / silica sol A silica surface area of 100 m ² ) was added and mixed with stirring. Thereafter, the mixture was reacted at 60 ° C. for 2 hours to obtain a silylated silica sol. While adding methyl ethyl ketone to the silylation-treated silica sol, the solvent was replaced by vacuum distillation at a pressure of 100 Torr so that the total liquid amount was constant. The amount of residual isopropanol in the obtained dispersion was 1.0% or less as analyzed by gas chromatography. The solid content concentration of the solvent-substituted silylation-treated silica sol was adjusted to 30% with methyl ethyl ketone to obtain dispersion Q-1.
This dispersion Q-1 was dried under reduced pressure at 50 ° C., pulverized, further dried at 110 ° C. for 1 hour, and subjected to elemental analysis. As a result, the carbon content was 0.26% by weight. This corresponds to 1.62 per 1 nm ^{2 of} surface area.

(Preparation of dispersion R-1)
Hollow silica fine particle sol (Isopropyl alcohol silica sol, CS60-IPA manufactured by Catalytic Chemical Industry Co., Ltd., average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20%), 500 parts, trimethylmethoxysilane 25 parts (2.9 mmol / silica sol) Of silica having a surface area of 100 m ² ) was added and mixed with stirring. Thereafter, the mixture was reacted at 60 ° C. for 2 hours to obtain a silylated silica sol. While adding methyl ethyl ketone to the silylation-treated silica sol, the solvent was replaced by vacuum distillation at a pressure of 100 Torr so that the total liquid amount was constant. The amount of residual isopropanol in the obtained dispersion was 1.0% or less as analyzed by gas chromatography. The solid content concentration of this solvent-substituted silylation-treated silica sol was adjusted to 30% with methyl ethyl ketone to obtain dispersion R-1.
This dispersion R-1 was dried at 50 ° C. under reduced pressure, pulverized, further dried at 110 ° C. for 1 hour, and subjected to elemental analysis. The carbon content was 0.88% by weight. This corresponds to 1.76 per 1 nm ^{2 of} surface area.

In the dispersion R-1, R- is exactly the same except that the silylation treatment agent represented by the general formula (I), the silylation treatment time, and the addition amount of the silylation treatment agent are changed as shown in Table 1. A dispersion of 2 to R-4 was prepared. The number of silyl groups per 1 nm ^{2 of the} fine particle surface area was evaluated by the same method as described above for the obtained dispersion.

[Example 1]
(Preparation of sol solution)
A stirrer, a reactor equipped with a reflux condenser, 120 parts of methyl ethyl ketone, 100 parts of acryloyloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts of diisopropoxyaluminum ethyl acetoacetate were added and mixed. Thereafter, 30 parts of ion-exchanged water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature to obtain sol solution a. The mass average molecular weight was 1600, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.

(Preparation of coating solution A for antiglare layer)
285.0 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.) was diluted with 175.0 g of methyl isobutyl ketone. Furthermore, 15.0 g of a polymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) was added and mixed and stirred. Subsequently, 60.0 g of a silane coupling agent (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred for 120 minutes with an air disper to completely dissolve the solute.
Finally, 30 of crosslinked poly (acryl-styrene) particles having an average particle diameter of 3.5 μm (copolymerization composition ratio = 50/50, refractive index 1.536) dispersed in this solution for 20 minutes at 10,000 rpm with a Polytron disperser. After adding 240.0 g of% methyl isobutyl ketone dispersion, 0.5 g of fluorine leveling agent FP-7, 112.5 g of methyl ethyl ketone and 112.5 g of propylene glycol were added, and the mixture was stirred with an air disper for 10 minutes.
The mixed solution was filtered through a polypropylene filter having a pore diameter of 30 μm to prepare a coating solution A for an antiglare layer.

(Adjustment of coating solution A for low refractive index layer)
12.5 g of a heat-crosslinkable fluorine-containing polymer having a refractive index of 1.44 containing polysiloxane and a hydroxyl group (JTA113, solid content concentration 6%, manufactured by JSR Corporation), a 30% dispersion of silica fine particles synthesized above 1.3 g, 0.6 g of sol solution a, 7.0 g of methyl ethyl ketone, and 0.6 g of cyclohexanone were added. After stirring, the solution was filtered through a polypropylene filter having a pore size of 1 μm to prepare a low refractive index layer coating solution A. The refractive index of the layer formed with this coating solution was 1.45.

(1) Coating of antiglare layer (antiglare hard coat layer) Using a slot die coater described in FIG. 1 of JP-A No. 2003-211052, a triacetylcellulose film (TAC-TD80U having a thickness of 80 μm). , Manufactured by Fuji Photo Film Co., Ltd.) in the form of a roll, and coated with an antiglare layer coating solution A at 17.3 g / m ² and dried at 30 ° C. for 15 seconds and 90 ° C. for 20 seconds. Thereafter, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm under a nitrogen purge, the coating layer was cured by irradiating ultraviolet rays with an irradiation amount of 90 mJ / cm ² , and having a thickness of 6 μm. An antiglare layer having antiglare properties was formed and wound up.
(2) Coating of low refractive index layer The triacetyl cellulose film coated with the antiglare layer coating liquid A and coated with the antiglare layer is unwound again, and the low refractive index layer coating liquid is applied with a bar coater. A was applied at 3.5 g / m ^2, dried at 120 ° C. for 150 seconds, further dried at 140 ° C. for 8 minutes, and then purged with nitrogen to 240 W / cm air-cooled metal halide lamp in an atmosphere with an oxygen concentration of 0.1%. (Igraphics Co., Ltd.) was used to irradiate ultraviolet rays having an irradiation amount of 300 mJ / cm ² to form a low refractive index layer having a thickness of 100 nm and wound up.
The antireflection film obtained by the above method was designated 1-1.

(Evaluation of hard coat film and antireflection film)
About these obtained samples, the following items were evaluated. The results are shown in Table 2.
(1) Evaluation of surface condition of hard coat film A sample having a coating width of 1.34 m × length of 25 cm coated only with a hard coat layer is black-coated on the back surface, and visually observed with reflected light. The degree was evaluated according to the following criteria.
A: Even if looked very carefully, no unevenness was seen.
○: Slightly weak unevenness is seen when viewed very carefully.
Δ: Weak unevenness is visible.
X: Medium unevenness is visible.
XX: Unevenness that can be seen at first glance.

(2) Fine particle aggregation observation Using an electron microscope, the coated surface side of each sample (sample coated with a coating solution for low refractive index layer containing inorganic oxide fine particles) was observed at a magnification of 5000 times to form a mesh. The degree of agglomeration of fine particles spreading to the surface was evaluated according to the following criteria.
A: No network-like fine particle aggregation is seen.
○: Although it does not spread in a mesh shape, slightly small particle aggregation can be seen.
Δ: Weak network-like fine particle aggregation is visible.
×: Clear fine mesh-like fine particle aggregates are visible. ××: Clear thick mesh-like fine particle aggregates are visible.

(3) Evaluation of average reflectance The spectrophotometer V-550 (manufactured by JASCO Corporation) is equipped with an adapter ARV-474, and in the wavelength region of 380 to 780 nm, the output angle is -5 degrees at the incident angle of 5 degrees. The specular reflectance was measured, an average reflectance of 450 to 650 nm was calculated, and antireflection properties were evaluated.

(4) Steel wool rubbing resistance evaluation A rubbing test was performed using a rubbing tester under the following conditions.
Evaluation environmental conditions: 25 ° C., 60% RH
Rub material: Steel wool (manufactured by Nippon Steel Wool Co., Ltd., Gelade No. 0000) was wound around the rubbing tip (1 cm × 1 cm) of a tester that was in contact with the sample, and the band was fixed so as not to move.
Moving distance (one way): 13 cm, rubbing speed: 13 cm / sec, load: 500 g / cm ² , tip contact area: 1 cm × 1 cm, rubbing frequency: 10 reciprocations.
An oil-based black ink was applied to the back side of the rubbed sample and visually observed with reflected light, and scratches on the rubbed portion were evaluated according to the following criteria.
A: Even if looked very carefully, no scratches were visible.
○: Slightly weak scratches are visible when viewed very carefully.
Δ: Weak scratches are visible.
X: A moderate crack is visible.
XX: There are scratches that can be seen at first glance.

When a fluorine-containing leveling agent is added to the antiglare layer, the surface shape is improved by the thickening effect. However, when a low refractive index layer using a comparative silica sol is applied as an upper layer, the reflectance increases, and the scratch resistance deteriorates. The application surface shape of the antiglare layer is not compatible with low reflectance and scratch resistance. It is considered that this is because the fluorine-containing leveling agent in the antiglare layer is eluted into the low refractive index layer and the silica particles are aggregated in a network.
When silica sol is used as a product of the present invention, there is no increase in reflectance, good scratch resistance, and no aggregation.
The antireflection film of the present invention is excellent in the surface shape of the antiglare layer, has no increase in reflectance, and has good scratch resistance.

[Example 2]
An antiglare layer was produced in exactly the same manner as the antiglare layer 1-1 except that various fluorine leveling agents were added to the antiglare layer, and a polymer polymer not containing fluorine atoms was further added.
These antiglare layers and low refractive index layers were combined as shown in Table 3 to complete an antireflection film.

When a fluorine leveling agent is added to the antiglare layer and the surface energy of the antiglare layer is 45 mJ / m ² or less, the coated surface shape is improved.
However, when a low refractive index layer using a comparative silica sol is applied as an upper layer, the reflectance increases, and the scratch resistance deteriorates. The application surface shape of the antiglare layer is not compatible with low reflectance and scratch resistance. This is thought to be because the surface energy of the antiglare layer is low due to the use of a fluorine leveling agent, and thus the silica particles of the low refractive index layer are aggregated in a network form during coating.
When silica sol is used as a product of the present invention, there is no increase in reflectance, good scratch resistance, and no aggregation.
The antireflection film of the present invention is excellent in the surface shape of the antiglare layer, has no increase in reflectance, and has good scratch resistance.
In addition, when a high molecular polymer not containing a fluorine atom was used in combination, a preferable antireflection film was obtained without any further improvement in the surface shape of the antiglare layer and without any increase in reflectance or deterioration of scratch resistance.

[Example 3]
An 80 μm-thick triacetylcellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.), which was immersed in an aqueous 1.5 mol / L, 55 ° C. NaOH solution for 2 minutes, then neutralized and washed with water, and Examples A polarizing plate was prepared by adhering and protecting both surfaces of a polarizing film prepared by adsorbing iodine to polyvinyl alcohol and stretching the film on one sample of the present invention (saponified). A liquid crystal display device of a notebook personal computer equipped with a transmissive TN liquid crystal display device (Sumitomo 3M Co., Ltd., which is a polarization separation film having a polarization selection layer) so that the anti-reflection film side is the outermost surface. When the polarizing plate on the viewing side of D-BEF made of the product between the backlight and the liquid crystal cell was replaced, a display device with very high display quality was obtained with very little background reflection.

[Example 4]
The PVA film was immersed in an aqueous solution of 2.0 g / l iodine and 4.0 g / l potassium iodide at 25 ° C. for 240 seconds, and further immersed in an aqueous solution of boric acid 10 g / l at 25 ° C. for 60 seconds. It introduced into the tenter drawing machine of the form of FIG. 2 described in 2002-86554, it extended | stretched 5.3 time, the tenter was bent like FIG. 2 with respect to the extending | stretching direction, and the width | variety was kept constant hereafter. After drying in an atmosphere of 80 ° C., it was detached from the tenter. The difference in transport speed between the left and right tenter clips was less than 0.05%, and the angle formed by the center line of the introduced film and the center line of the film sent to the next process was 46 °. Here, | L1-L2 | is 0.7 m, W is 0.7 m, and | L1-L2 | = W. The substantial stretching direction Ax-Cx at the tenter outlet was inclined by 45 ° with respect to the center line 22 of the film sent to the next process. Wrinkles and film deformation at the tenter exit were not observed.
Furthermore, it was bonded to Fuji Photo Film Co., Ltd. Fujitac (cellulose triacetate, retardation value 3.0 nm), which was saponified with an aqueous solution of PVA (Pura-117H, Kuraray Co., Ltd.) 3%, and further 80 ° C. And dried to obtain a polarizing plate having an effective width of 650 mm. The absorption axis direction of the obtained polarizing plate was inclined 45 ° with respect to the longitudinal direction. The polarizing plate had a transmittance at 550 nm of 43.7% and a polarization degree of 99.97%. Further, when the substrate was cut into a size of 310 × 233 mm, a polarizing plate having a 45 ° absorption axis inclined with respect to the side with an area efficiency of 91.5% was obtained.
Next, each film of the inventive sample of Example 1 (saponified) was bonded to the above polarizing plate to produce a polarizing plate with antireflection. Using this polarizing plate, a liquid crystal display device having an antireflection layer as the outermost layer was produced. As a result, there was no reflection of external light, and an excellent contrast was obtained, and the reflected image was not noticeable and had excellent visibility. Was.

[Example 5]
As a protective film on the liquid crystal cell side of the polarizing plate on the viewing side of the transmission type TN liquid crystal cell to which the sample of the present invention of Example 1 was attached, and as a protective film on the liquid crystal cell side of the polarizing plate on the backlight side, an optical compensation film ( Using Wide View Film Ace (Fuji Photo Film Co., Ltd.), a liquid crystal display device with excellent contrast in a bright room, extremely wide viewing angles in the top, bottom, left and right, extremely excellent visibility, and high display quality was gotten.

[Example 6]
Using cellulose acylate having an acetyl substitution degree of 2.94, the following optical anisotropy reducing agent X was 49.3% (vs. cellulose acylate), and the following chromatic dispersion adjusting agent Y was 7.6% (vs. cellulose acylate). ) To prepare a cellulose acylate sample 201 having a thickness of 80 μm by the same film forming method as in Example 1. The retardation Re of the obtained film was −1.0 nm (negative because of the slow axis in the TD direction), and the retardation Rth in the thickness direction was −2.0 nm, both sufficiently small values. This cellulose acylate film sample was used as a transparent support for the protective film on the cell side of the two protective films of the polarizer, and Example 1 of the present invention was used as the protective film on the viewing side of the polarizer. Liquid crystal display device described in Example 1 of Japanese Patent Publication No. JP-A-9-26572, an optically anisotropic layer containing discotic liquid crystal molecules described in Example 1 of Japanese Patent Application Laid-Open No. 9-26572, an alignment film coated with polyvinyl alcohol, -154261 in FIGS. 2 to 9 of the VA type liquid crystal display device and JP2000-154261 of the OCB type liquid crystal display device in FIGS. Performance with good contrast viewing angle was obtained.

[Example 7]
When the inventive sample of Example 1 was bonded to the glass plate on the surface of the organic EL display device via an adhesive, reflection on the glass surface was suppressed, and a display device with high visibility was obtained.

[Example 8]
Using the sample of the present invention of Example 1, a polarizing plate with a single-sided antireflection film was prepared, and a λ / 4 plate was laminated on the opposite side of the polarizing plate on the side having the antireflection film, with the antireflection film side closest to the antireflection film side. When attached to the glass plate on the surface of the organic EL display device so as to be on the surface, the surface reflection and the reflection from the inside of the surface glass were cut, and a display with extremely high visibility was obtained.

Claims (8)

In an optical film having at least one hard coat layer on a transparent support and further having an optical functional layer containing inorganic fine particles as an upper layer, the surface energy of the hard coat layer is 45 mJ / m ² or less, and An optical film characterized in that the inorganic fine particles contained in the optical functional layer contain 1.1 or more silyl groups per 1 nm ^{2 of} the surface area.   The said hard-coat layer of Claim 1 contains a fluorine-type leveling agent or a silicone type leveling agent, The optical film characterized by the above-mentioned.   The optical film, wherein the hard coat layer according to claim 1 or 2 contains a high molecular polymer substantially free of fluorine atoms and silicon atoms.   The antireflection film according to claim 1, wherein the inorganic fine particles are hollow inorganic oxide particles.   The anti-reflection film according to claim 1, wherein the optical functional layer is a low refractive index layer.   In the polarizing plate formed by sandwiching a polarizer between two protective films, one protective film of the polarizing plate is the optical film according to any one of claims 1 to 3 or any one of claims 4 to 5. A polarizing plate, which is an antireflection film.   A display device comprising the polarizing plate according to claim 6.   A display device comprising the optical film according to claim 1 or the antireflection film according to any one of claims 4 to 5.